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Sample records for acclimation affects clinal

  1.     Developmental acclimation affects clinal variation in stress resistance traits in Drosophila buzzatii

    DEFF Research Database (Denmark)

    Sarup, Pernille Merete; Loeschcke, Volker

    2010-01-01

    -down resistance after development at either constant or fluctuating temperatures in nine Drosophila buzzatii populations collected along an altitudinal gradient in Tenerife, Spain. Flies that developed at fluctuating temperatures had higher stress resistance despite experiencing a slightly lower average...

  2. Diet affects resting, but not basal metabolic rate of normothermic Siberian hamsters acclimated to winter.

    Science.gov (United States)

    Gutowski, Jakub P; Wojciechowski, Michał S; Jefimow, Małgorzata

    2011-12-01

    We examined the effect of different dietary supplements on seasonal changes in body mass (m(b)), metabolic rate (MR) and nonshivering thermogenesis (NST) capacity in normothermic Siberian hamsters housed under semi-natural conditions. Once a week standard hamster food was supplemented with either sunflower and flax seeds, rich in polyunsaturated fatty acids (FA), or mealworms, rich in saturated and monounsaturated FA. We found that neither of these dietary supplements affected the hamsters' normal winter decrease in m(b) and fat content nor their basal MR or NST capacity. NST capacity of summer-acclimated hamsters was lower than that of winter-acclimated ones. The composition of total body fat reflected the fat composition of the dietary supplements. Resting MR below the lower critical temperature of the hamsters, and their total serum cholesterol concentration were lower in hamsters fed a diet supplemented with mealworms than in hamsters fed a diet supplemented with seeds. These results indicate that in mealworm-fed hamsters energy expenditure in the cold is lower than in animals eating a seed-supplemented diet, and that the degree of FA unsaturation of diet affects energetics of heterotherms, not only during torpor, but also during normothermy.

  3. Thermal acclimation and nutritional history affect the oxidation of different classes of exogenous nutrients in Siberian hamsters, Phodopus sungorus.

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    McCue, Marshall D; Voigt, Christian C; Jefimow, Małgorzata; Wojciechowski, Michał S

    2014-11-01

    During acclimatization to winter, changes in morphology and physiology combined with changes in diet may affect how animals use the nutrients they ingest. To study (a) how thermal acclimation and (b) nutritional history affect the rates at which Siberian hamsters (Phodopus sungorus) oxidize different classes of dietary nutrients, we conducted two trials in which we fed hamsters one of three (13) C-labeled compounds, that is, glucose, leucine, or palmitic acid. We predicted that under acute cold stress (3 hr at 2°C) hamsters previously acclimated to cold temperatures (10°C) for 3 weeks would have higher resting metabolic rate (RMR) and would oxidize a greater proportion of dietary fatty acids than animals acclimated to 21°C. We also investigated how chronic nutritional stress affects how hamsters use dietary nutrients. To examine this, hamsters were fed four different diets (control, low protein, low lipid, and low-glycemic index) for 2 weeks. During cold challenges, hamsters previously acclimated to cold exhibited higher thermal conductance and RMR, and also oxidized more exogenous palmitic acid during the postprandial phase than animals acclimated to 21°C. In the nutritional stress trial, hamsters fed the low protein diet oxidized more exogenous glucose, but not more exogenous palmitic acid than the control group. The use of (13) C-labeled metabolic tracers combined with breath testing demonstrated that both thermal and nutritional history results in significant changes in the extent to which animals oxidize dietary nutrients during the postprandial period.

  4. Does acclimation at higher temperatures affect the locomotor performance of one of the southernmost reptiles in the world?

    Directory of Open Access Journals (Sweden)

    Jimena B. Fernández

    2012-12-01

    Full Text Available When an animal in the laboratory experiences a change in temperature, physiological processes are affected but they stabilize under the new temperature condition over a few weeks by a process of phenotypic plasticity called acclimation, but whether an organism can acclimate or not depends on the trait and the taxon. Liolaemus sarmientoi is one of the southernmost reptiles in the world, inhabiting the extreme and arid environment of Patagonia, Argentina, characterised by great seasonal climatic variation and cold air temperatures throughout the year (mean air temperature of 8 °C; ranging from 1.2 to 14.1 °C. However, these lizards prefer body temperatures in the laboratory ranging from 26.3 to 37.8 °C (mean Tpref = 34.4 ± 0.28 °C, temperatures that they rarely achieve in nature. Herein, we explore the effects of thermal acclimation on performance of L. sarmientoi at a temperature higher than their mean natural environmental temperature during their activity period (austral spring-summer. We analysed the speed in sprint and long runs at medium and high temperatures in the field and again after a period of acclimation of 20 days at 21 °C. Acclimation to higher and constant temperature resulted in a decrease in running speed in both long and sprint runs, suggesting potentially negative effects for natural populations if environmental temperature increases.

  5. Elevated temperature and acclimation time affect metabolic performance in the heavily exploited Nile perch of Lake Victoria.

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    Nyboer, Elizabeth A; Chapman, Lauren J

    2017-08-18

    Increasing water temperatures due to anthropogenic climate change are predicted to negatively impact the aerobic metabolic performance of aquatic ectotherms. Specifically, it has been hypothesized that thermal increases result in reductions in aerobic scope (AS), which lead to decreases in energy available for essential fitness and performance functions. Consequences of warming are anticipated to be especially severe for warm-adapted tropical species as they are thought to have narrow thermal windows and limited plasticity for coping with elevated temperatures. In this study we test how predicted warming may affect the aerobic performance of Nile perch (Lates niloticus), a commercially-harvested fish species in the Lake Victoria basin of East Africa. We measured critical thermal maxima (CTmax) and key metabolic variables such as AS and excess post-exercise oxygen consumption (EPOC) across a range of temperatures, and compared responses between acute (3-day) exposures and 3-week acclimations. CTmax increased with acclimation temperature, however 3-week acclimated fish had higher overall CTmax than acutely-exposed individuals. Nile perch also showed the capacity to increase or maintain high AS even at temperatures well beyond their current range, however acclimated Nile perch had lower AS compared to acutely-exposed fish. These changes were accompanied by lower EPOC, suggesting that drops in AS may reflect improved energy utilization after acclimation, a finding that is supported by improvements in growth at high temperatures over the acclimation period. Overall, the results challenge predictions that tropical species have limited thermal plasticity, and that high temperatures will be detrimental due to limitations in AS. © 2017. Published by The Company of Biologists Ltd.

  6. The DnaJ-like zinc finger domain protein PSA2 affects light acclimation and chloroplast development in Arabidopsis thaliana

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    Yan-Wen eWang

    2016-03-01

    Full Text Available The biosynthesis of chlorophylls and carotenoids and the assembly of thylakoid membranes are critical for the photoautotrophic growth of plants. Different factors are involved in these two processes. In recent years, members of the DnaJ-like zinc finger domain proteins have been found to take part in the biogenesis and/or the maintenance of plastids. One member of this family of proteins, PSA2, was recently found to localize to the thylakoid lumen and regulate the accumulation of photosystem I. In this study, we report that the silencing of PSA2 in Arabidopsis thaliana resulted in variegated leaves and retarded growth. Although both chlorophylls and total carotenoids decreased in the psa2 mutant, violaxanthin and zeaxanthin accumulated in the mutant seedlings grown under growth condition. Lower levels of non-photochemical quenching and electron transport rate were also found in the psa2 mutant seedlings under growth condition compared with those of the wild-type plants, indicating an impaired capability to acclimate to normal light irradiance when PSA2 was silenced. Moreover, we also observed an abnormal assembly of grana thylakoids and poorly developed stroma thylakoids in psa2 chloroplasts. Taken together, our results demonstrate that PSA2 is a member of the DnaJ-like zinc finger domain protein family that affects light acclimation and chloroplast development.

  7. Long-Term Acclimation to Different Thermal Regimes Affects Molecular Responses to Heat Stress in a Freshwater Clam Corbicula Fluminea

    Science.gov (United States)

    Falfushynska, Halina I.; Phan, Tuan; Sokolova, Inna M.

    2016-12-01

    Global climate change (GCC) can negatively affect freshwater ecosystems. However, the degree to which freshwater populations can acclimate to long-term warming and the underlying molecular mechanisms are not yet fully understood. We used the cooling water discharge (CWD) area of a power plant as a model for long-term warming. Survival and molecular stress responses (expression of molecular chaperones, antioxidants, bioenergetic and protein synthesis biomarkers) to experimental warming (20–41 °C, +1.5 °C per day) were assessed in invasive clams Corbicula fluminea from two pristine populations and a CWD population. CWD clams had considerably higher (by ~8–12 °C) lethal temperature thresholds than clams from the pristine areas. High thermal tolerance of CWD clams was associated with overexpression of heat shock proteins HSP70, HSP90 and HSP60 and activation of protein synthesis at 38 °C. Heat shock response was prioritized over the oxidative stress response resulting in accumulation of oxidative lesions and ubiquitinated proteins during heat stress in CWD clams. Future studies should determine whether the increase in thermal tolerance in CWD clams are due to genetic adaptation and/or phenotypic plasticity. Overall, our findings indicate that C. fluminea has potential to survive and increase its invasive range during warming such as expected during GCC.

  8. Stress acclimation and particulate matter accumulation in Pinus sylvestris saplings affected by moderate combinations of urban stressors.

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    Hanslin, Hans Martin; Przybysz, Arkadiusz; Slimestad, Rune; Sæbø, Arne

    2017-09-01

    To predict how the function of urban vegetation and the provision of ecosystem services respond to combinations of natural and anthropogenic drivers, a better understanding of multiple stress interactions is required. This study tested combined effects of moderate levels of drought, soil salinity and exposure to diesel exhaust on parameters of physiology, metabolism, morphology and growth of Pinus sylvestris L. saplings. We found that plant responses were primarily dominated by single stressors and a few two-way interactions. Stressor combinations did not have considerable additional negative effects on plant performance compared to single stressors. Hence, synergistic and antagonistic interactions were rare and additive effects frequent. Drought cycles caused most negative effects, from chlorophyll a fluorescence and epicuticular wax content to growth responses, while soil salinity caused fewer negative effects but contributed to reduction in fine root growth and fluorescence parameters at low air contamination. Interestingly, the air contamination alone had only marginal effects on plant morphology and growth, but contributed an antagonistic effect, dampening the negative effect of drought and salinity on the maximum quantum efficiency of PSII photochemistry (Fv/Fm) and fine root biomass. Although, these effects were moderate, it appears that exhaust exposure had a cross-acclimation effect on plant responses to drought and salinity. We also found that salinity had a negative effect on the accumulation of particulate matter on shoots, illustrating that the plant stress situation can affect the provisioning of certain ecosystem services like pollution attenuation. These findings have implications for the understanding of the complex natural and anthropogenic stress situation of urban, and how to maintain the ecological functions and delivery of ecosystem services. Copyright © 2017 Elsevier B.V. All rights reserved.

  9. Daily Acclimation Handling Does Not Affect Hippocampal Long-Term Potentiation or Cause Chronic Sleep Deprivation in Mice

    NARCIS (Netherlands)

    Vecsey, Christopher G.; Wimmer, Mathieu E. J.; Havekes, Robbert; Park, Alan J.; Perron, Isaac J.; Meerlo, Peter; Abel, Ted

    2013-01-01

    Study Objectives: Gentle handling is commonly used to perform brief sleep deprivation in rodents. It was recently reported that daily acclimation handling, which is often used before behavioral assays, causes alterations in sleep, stress, and levels of N-methyl-D-aspartate receptor subunits prior to

  10. Daily Acclimation Handling Does Not Affect Hippocampal Long-Term Potentiation or Cause Chronic Sleep Deprivation in Mice

    NARCIS (Netherlands)

    Vecsey, Christopher G.; Wimmer, Mathieu E. J.; Havekes, Robbert; Park, Alan J.; Perron, Isaac J.; Meerlo, Peter; Abel, Ted

    2013-01-01

    Study Objectives: Gentle handling is commonly used to perform brief sleep deprivation in rodents. It was recently reported that daily acclimation handling, which is often used before behavioral assays, causes alterations in sleep, stress, and levels of N-methyl-D-aspartate receptor subunits prior to

  11. Daily acclimation handling does not affect hippocampal long-term potentiation or cause chronic sleep deprivation in mice.

    Science.gov (United States)

    Vecsey, Christopher G; Wimmer, Mathieu E J; Havekes, Robbert; Park, Alan J; Perron, Isaac J; Meerlo, Peter; Abel, Ted

    2013-04-01

    Gentle handling is commonly used to perform brief sleep deprivation in rodents. It was recently reported that daily acclimation handling, which is often used before behavioral assays, causes alterations in sleep, stress, and levels of N-methyl-D-aspartate receptor subunits prior to the actual period of sleep deprivation. It was therefore suggested that acclimation handling could mediate some of the observed effects of subsequent sleep deprivation. Here, we examine whether acclimation handling, performed as in our sleep deprivation studies, alters sleep/wake behavior, stress, or forms of hippocampal synaptic plasticity that are impaired by sleep deprivation. Adult C57BL/6J mice were either handled daily for 6 days or were left undisturbed in their home cages. On the day after the 6(th) day of handling, long-term potentiation (LTP) was induced in hippocampal slices with spaced four-train stimulation, which we previously demonstrated to be impaired by brief sleep deprivation. Basal synaptic properties were also assessed. In three other sets of animals, activity monitoring, polysomnography, and stress hormone measurements were performed during the 6 days of handling. Daily gentle handling alone does not alter LTP, rest/activity patterns, or sleep/wake architecture. Handling initially induces a minimal stress response, but by the 6(th) day, stress hormone levels are unaltered by handling. It is possible to handle mice daily to accustom them to the researcher without causing alterations in sleep, stress, or synaptic plasticity in the hippocampus. Therefore, effects of acclimation handling cannot explain the impairments in signaling mechanisms, synaptic plasticity, and memory that result from brief sleep deprivation.

  12. Cr(Vi) reduction capacity of activated sludge as affected by nitrogen and carbon sources, microbial acclimation and cell multiplication

    Energy Technology Data Exchange (ETDEWEB)

    Ferro Orozco, A.M., E-mail: mferro@cidca.org.ar [Centro de Investigacion y Desarrollo en Criotecnologia de Alimentos (CIDCA) CCT La Plata CONICET - Fac. de Cs. Exactas, UNLP. 47 y 116 (B1900AJJ) La Plata (Argentina); Contreras, E.M.; Zaritzky, N.E. [Centro de Investigacion y Desarrollo en Criotecnologia de Alimentos (CIDCA) CCT La Plata CONICET - Fac. de Cs. Exactas, UNLP. 47 y 116 (B1900AJJ) La Plata (Argentina); Fac. de Ingenieria, UNLP. 47 y 1 (B1900AJJ) - La Plata (Argentina)

    2010-04-15

    The objectives of the present work were: (i) to analyze the capacity of activated sludge to reduce hexavalent chromium using different carbon sources as electron donors in batch reactors, (ii) to determine the relationship between biomass growth and the amount of Cr(VI) reduced considering the effect of the nitrogen to carbon source ratio, and (iii) to determine the effect of the Cr(VI) acclimation stage on the performance of the biological chromium reduction assessing the stability of the Cr(VI) reduction capacity of the activated sludge. The highest specific Cr(VI) removal rate (q{sub Cr}) was attained with cheese whey or lactose as electron donors decreasing in the following order: cheese whey {approx} lactose > glucose > citrate > acetate. Batch assays with different nitrogen to carbon source ratio demonstrated that biological Cr(VI) reduction is associated to the cell multiplication phase; as a result, maximum Cr(VI) removal rates occur when there is no substrate limitation. The biomass can be acclimated to the presence of Cr(VI) and generate new cells that maintain the ability to reduce chromate. Therefore, the activated sludge process could be applied to a continuous Cr(VI) removal process.

  13. Bacterial Acclimation Inside an Aqueous Battery.

    Directory of Open Access Journals (Sweden)

    Dexian Dong

    Full Text Available Specific environmental stresses may lead to induced genomic instability in bacteria, generating beneficial mutants and potentially accelerating the breeding of industrial microorganisms. The environmental stresses inside the aqueous battery may be derived from such conditions as ion shuttle, pH gradient, free radical reaction and electric field. In most industrial and medical applications, electric fields and direct currents are used to kill bacteria and yeast. However, the present study focused on increasing bacterial survival inside an operating battery. Using a bacterial acclimation strategy, both Escherichia coli and Bacillus subtilis were acclimated for 10 battery operation cycles and survived in the battery for over 3 days. The acclimated bacteria changed in cell shape, growth rate and colony color. Further analysis indicated that electrolyte concentration could be one of the major factors determining bacterial survival inside an aqueous battery. The acclimation process significantly improved the viability of both bacteria E. coli and B. subtilis. The viability of acclimated strains was not affected under battery cycle conditions of 0.18-0.80 mA cm(-2 and 1.4-2.1 V. Bacterial addition within 1.0×10(10 cells mL(-1 did not significantly affect battery performance. Because the environmental stress inside the aqueous battery is specific, the use of this battery acclimation strategy may be of great potential for the breeding of industrial microorganisms.

  14. Bacterial Acclimation Inside an Aqueous Battery.

    Science.gov (United States)

    Dong, Dexian; Chen, Baoling; Chen, P

    2015-01-01

    Specific environmental stresses may lead to induced genomic instability in bacteria, generating beneficial mutants and potentially accelerating the breeding of industrial microorganisms. The environmental stresses inside the aqueous battery may be derived from such conditions as ion shuttle, pH gradient, free radical reaction and electric field. In most industrial and medical applications, electric fields and direct currents are used to kill bacteria and yeast. However, the present study focused on increasing bacterial survival inside an operating battery. Using a bacterial acclimation strategy, both Escherichia coli and Bacillus subtilis were acclimated for 10 battery operation cycles and survived in the battery for over 3 days. The acclimated bacteria changed in cell shape, growth rate and colony color. Further analysis indicated that electrolyte concentration could be one of the major factors determining bacterial survival inside an aqueous battery. The acclimation process significantly improved the viability of both bacteria E. coli and B. subtilis. The viability of acclimated strains was not affected under battery cycle conditions of 0.18-0.80 mA cm(-2) and 1.4-2.1 V. Bacterial addition within 1.0×10(10) cells mL(-1) did not significantly affect battery performance. Because the environmental stress inside the aqueous battery is specific, the use of this battery acclimation strategy may be of great potential for the breeding of industrial microorganisms.

  15. Arabidopsis thaliana populations show clinal variation in a climatic gradient associated with altitude.

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    Montesinos-Navarro, Alicia; Wig, Jennifer; Pico, F Xavier; Tonsor, Stephen J

    2011-01-01

    • Understanding the adaptive basis of life history variation is a central goal in evolutionary ecology. The use of model species enables the combination of molecular mechanistic knowledge with ecological and evolutionary questions, but the study of life history variation in natural environments is required to merge these disciplines. • Here, we tested for clinal variation in life history and associated traits along an environmental and altitudinal gradient in the model species Arabidopsis thaliana. Seventeen natural populations of A. thaliana were geo-referenced in north-eastern Spain on a gradient in which precipitation increases but maximum spring temperature and minimum winter temperature decrease with altitude. • One hundred and eighty-nine genotypes from the 17 populations were grown under uniform controlled conditions. Variations in traits related to biomass allocation, fecundity, phenology and vegetative growth were tested for relationships with the altitude and climatic variables associated with the home sites. Above-ground mass, number of rosette leaves at bolting, developmental time and seed weight increased with the home site's altitude. Root allocation, vegetative growth during winter and number of seeds decreased with altitude. • We suggest that the differences among home sites provide clues to the variation in adaptive strategies associated with the climatic gradient. We compared these results with adaptations and clinal relationships reported for other species and with molecular mechanisms described in Arabidopsis.

  16. Integrating landscape genomics and spatially explicit approaches to detect loci under selection in clinal populations.

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    Jones, Matthew R; Forester, Brenna R; Teufel, Ashley I; Adams, Rachael V; Anstett, Daniel N; Goodrich, Betsy A; Landguth, Erin L; Joost, Stéphane; Manel, Stéphanie

    2013-12-01

    Uncovering the genetic basis of adaptation hinges on the ability to detect loci under selection. However, population genomics outlier approaches to detect selected loci may be inappropriate for clinal populations or those with unclear population structure because they require that individuals be clustered into populations. An alternate approach, landscape genomics, uses individual-based approaches to detect loci under selection and reveal potential environmental drivers of selection. We tested four landscape genomics methods on a simulated clinal population to determine their effectiveness at identifying a locus under varying selection strengths along an environmental gradient. We found all methods produced very low type I error rates across all selection strengths, but elevated type II error rates under "weak" selection. We then applied these methods to an AFLP genome scan of an alpine plant, Campanula barbata, and identified five highly supported candidate loci associated with precipitation variables. These loci also showed spatial autocorrelation and cline patterns indicative of selection along a precipitation gradient. Our results suggest that landscape genomics in combination with other spatial analyses provides a powerful approach for identifying loci potentially under selection and explaining spatially complex interactions between species and their environment.

  17. Clinal variation at phenology-related genes in spruce: parallel evolution in FTL2 and Gigantea?

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    Chen, Jun; Tsuda, Yoshiaki; Stocks, Michael; Källman, Thomas; Xu, Nannan; Kärkkäinen, Katri; Huotari, Tea; Semerikov, Vladimir L; Vendramin, Giovanni G; Lascoux, Martin

    2014-07-01

    Parallel clines in different species, or in different geographical regions of the same species, are an important source of information on the genetic basis of local adaptation. We recently detected latitudinal clines in SNPs frequencies and gene expression of candidate genes for growth cessation in Scandinavian populations of Norway spruce (Picea abies). Here we test whether the same clines are also present in Siberian spruce (P. obovata), a close relative of Norway spruce with a different Quaternary history. We sequenced nine candidate genes and 27 control loci and genotyped 14 SSR loci in six populations of P. obovata located along the Yenisei river from latitude 56°N to latitude 67°N. In contrast to Scandinavian Norway spruce that both departs from the standard neutral model (SNM) and shows a clear population structure, Siberian spruce populations along the Yenisei do not depart from the SNM and are genetically unstructured. Nonetheless, as in Norway spruce, growth cessation is significantly clinal. Polymorphisms in photoperiodic (FTL2) and circadian clock (Gigantea, GI, PRR3) genes also show significant clinal variation and/or evidence of local selection. In GI, one of the variants is the same as in Norway spruce. Finally, a strong cline in gene expression is observed for FTL2, but not for GI. These results, together with recent physiological studies, confirm the key role played by FTL2 and circadian clock genes in the control of growth cessation in spruce species and suggest the presence of parallel adaptation in these two species.

  18. Maintenance of clinal variation for shell colour phenotype in the flat periwinkle Littorina obtusata.

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    Phifer-Rixey, M; Heckman, M; Trussell, G C; Schmidt, P S

    2008-07-01

    Clines can signal spatially varying selection and therefore have long been used to investigate the role of environmental heterogeneity in maintaining genetic variation. However, clinal patterns alone are not sufficient to reject neutrality or to establish the mechanism of selection. Indirect, inferential methods can be used to address neutrality and mechanism, but fully understanding the adaptive significance of clinal variation ultimately requires a direct approach. Ecological model systems such as the rocky intertidal provide a useful context for direct experimentation and can serve as a complement to studies in more traditional genetic model systems. In this study, we use indirect and direct approaches to investigate the role of environmental heterogeneity in the maintenance of shell colour polymorphism in the flat periwinkle snail, Littorina obtusata. We document replicated clines in shell colour morph frequencies over thermal gradients at two spatial scales, contrasting with patterns at previously reported microsatellite loci. In addition, experimental results demonstrate that that shell colour has predictable effects on shell temperature and that these differences in temperature, in turn, coincide with patterns of survivorship under episodic thermal stress. Direct manipulation of shell colour revealed that shell colour, and not a correlated character, was the target of selection. Our study provides evidence that spatially varying selection via thermal regime contributes to the maintenance of shell colour phenotype variation in L. obtusata in the sampled areas of the Gulf of Maine.

  19. Effect of thermal acclimation on thermal preference, resistance and locomotor performance of hatchling soft-shelled turtle

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    Mei-Xian WU,Ling-Jun HU, Wei DANG, Hong-Liang LU, Wei-Guo DU

    2013-12-01

    Full Text Available The significant influence of thermal acclimation on physiological and behavioral performance has been documented in many ectothermic animals, but such studies are still limited in turtle species. We acclimated hatchling soft-shelled turtles Pelodiscus sinensis under three thermal conditions (10, 20 and 30 °C for 4 weeks, and then measured selected body temperature (Tsel, critical thermal minimum (CTMin and maximum (CTMax, and locomotor performance at different body temperatures. Thermal acclimation significantly affected thermal preference and resistance of P. sinensis hatchlings. Hatchling turtles acclimated to 10 °C selected relatively lower body temperatures and were less resistant to high temperatures than those acclimated to 20 °C and 30 °C. The turtles’ resistance to low temperatures increased with a decreasing acclimation temperature. The thermal resistance range (i.e. the difference between CTMax and CTMin, TRR was widest in turtles acclimated to 20 °C, and narrowest in those acclimated to 10 °C. The locomotor performance of turtles was affected by both body temperature and acclimation temperature. Hatchling turtles acclimated to relatively higher temperatures swam faster than did those acclimated to lower temperatures. Accordingly, hatchling turtles acclimated to a particular temperature may not enhance the performance at that temperature. Instead, hatchlings acclimated to relatively warm temperatures have a better performance, supporting the “hotter is better” hypothesis [Current Zoology 59 (6 : 718–724, 2013 ].

  20. Seawater Acclimation of Spirulina

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    Shaochen GUAN; Yixuan LI; Gan WANG; Lang QIN; Yi ZHU; Yunbo LUO

    2012-01-01

    Abstract [Objective] This study aimed to seek the cultivation method for Spirulina with seawater. [Method] Spirulina was habituated culture progressively with pre- pared seawater acclimation solution. The morphological changes of Spirulina were observed and its biochemical indicators were measured. [Result] A new algae species was obtained, which had better stability and greater average length than Spirulina in fresh water. Compared with the Spirulina in fresh water, the new al- gae species showed no significant change in chlorophyll content, but a 62.8% in- crease in the concentration of phycocyanin. [Conclusion] The method could save resources and cost, which lays the foundation for large scale production and processing of Spirulina.

  1. Distribution and clinal trends of the ABO and Rh genes in select Middle Eastern countries.

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    AlSuhaibani, E S; Kizilbash, N A; Afshan, K; Malik, S

    2015-09-09

    An understanding of the ABO and Rh blood group systems is important for blood transfusions and is also pertinent due to their potential association with certain morbidities and susceptibilities to infections. To investigate the diversity and differentiation of the ABO and Rh loci in Middle Eastern populations, data from twelve representative Middle Eastern populations were analyzed. Six populations were in conformity with Hardy-Weinberg equilibrium at the ABO locus. The pooled heterozygosity at both loci was calculated to be highest in the sample from Jordan and lowest in Bahrain. Heterogeneity was pronounced in the Northern compared to the Southern Middle Eastern populations. Overall, the absolute gene diversity was 0.0046 and gene differentiation was calculated to be 0.0100. Genetic diversity of the studied loci across all populations (HT) was estimated to be 0.4594, while the diversity within the populations (HS) was 0.4548. Nei's genetic distance analyses revealed highest affinities between the populations of Kuwait and Qatar, Oman and Yemen, and between Qatar and the United Arab Emirates. These results were displayed through a UGPMA dendrogram and principal component analyses, which established clustering of certain populations. Clinal trends of the allelic systems were observed by generating contour maps that allow a detailed appreciation of the distributions of alleles across the geography of the Arabian Peninsula and the Middle East. Taken together, these analyses are helpful in understanding the differentiation of blood group loci and for designing prospective studies for establishing the associations of these loci with health variables in the populations studied.

  2. Clinal adaptation and adaptive plasticity in Artemisia californica: implications for the response of a foundation species to predicted climate change.

    Science.gov (United States)

    Pratt, Jessica D; Mooney, Kailen A

    2013-08-01

    Local adaptation and plasticity pose significant obstacles to predicting plant responses to future climates. Although local adaptation and plasticity in plant functional traits have been documented for many species, less is known about population-level variation in plasticity and whether such variation is driven by adaptation to environmental variation. We examined clinal variation in traits and performance - and plastic responses to environmental change - for the shrub Artemisia californica along a 700 km gradient characterized (from south to north) by a fourfold increase in precipitation and a 61% decrease in interannual precipitation variation. Plants cloned from five populations along this gradient were grown for 3 years in treatments approximating the precipitation regimes of the north and south range margins. Most traits varying among populations did so clinally; northern populations (vs. southern) had higher water-use efficiencies and lower growth rates, C : N ratios and terpene concentrations. Notably, there was variation in plasticity for plant performance that was strongly correlated with source site interannual precipitation variability. The high-precipitation treatment (vs. low) increased growth and flower production more for plants from southern populations (181% and 279%, respectively) than northern populations (47% and 20%, respectively). Overall, precipitation variability at population source sites predicted 86% and 99% of variation in plasticity in growth and flowering, respectively. These striking, clinal patterns in plant traits and plasticity are indicative of adaptation to both the mean and variability of environmental conditions. Furthermore, our analysis of long-term coastal climate data in turn indicates an increase in interannual precipitation variation consistent with most global change models and, unexpectedly, this increased variation is especially pronounced at historically stable, northern sites. Our findings demonstrate the

  3. Sublethal toxicity of chlorpyrifos to salmonid olfaction after hypersaline acclimation.

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    Maryoung, Lindley A; Blunt, Brian; Tierney, Keith B; Schlenk, Daniel

    2015-04-01

    Salmonid habitats can be impacted by several environmental factors, such as salinization, which can also affect salmonid tolerance to anthropogenic stressors, such as pesticides. Previous studies have shown that hypersaline acclimation enhances the acute toxicity of certain organophosphate and carbamate pesticides to euryhaline fish; however, sublethal impacts have been far less studied. The current study aims to determine how hypersaline acclimation and exposure to the organophosphate chlorpyrifos (CPF) impact salmonid olfaction. Combined acclimation and exposure to CPF was shown to impact rainbow trout olfaction at the molecular, physiological, and behavioral levels. Concurrent exposure to hypersalinity and 0.5μg/L CPF upregulated four genes (chloride intracellular channel 4, G protein zgc:101761, calcium calmodulin dependent protein kinase II delta, and adrenergic alpha 2C receptor) that inhibit olfactory signal transduction. At the physiological level, hypersalinity and chlorpyrifos caused a decrease in sensory response to the amino acid l-serine and the bile salt taurocholic acid. Combined acclimation and exposure also negatively impacted behavior and reduced the avoidance of a predator cue (l-serine). Thus, acclimation to hypersaline conditions and exposure to environmentally relevant concentrations of chlorpyrifos caused an inhibition of olfactory signal transduction leading to a decreased response to odorants and impairment of olfactory mediated behaviors.

  4. A new species of slender coralsnake from Colombia, and its clinal an ontogenetic variation (Serpentes, Elapidae: Leptomicrurus).

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    Lamar, William W

    2003-01-01

    Leptomicrurus renjifoi is described from tropical semi-deciduous forest of the eastern Colombian Ilanos. It is one of the smallest species in the genus, is most similar to L. scutiventris, and it may be distinguished from known congeners by a combination of color, pattern, and scale characters. Evidence for the recognition of Leptomicrurus is convincing, although its members were recently thought to comprise a closely related assemblage within Micrurus. A supposedly aberrant specimen of L. scutiventris may indicate clinal or ontogenetic variation in pattern.

  5. Y-Chromosomal Diversity in Europe Is Clinal and Influenced Primarily by Geography, Rather than by Language

    Science.gov (United States)

    Rosser, Zoë H.; Zerjal, Tatiana; Hurles, Matthew E.; Adojaan, Maarja; Alavantic, Dragan; Amorim, António; Amos, William; Armenteros, Manuel; Arroyo, Eduardo; Barbujani, Guido; Beckman, Gunhild; Beckman, Lars; Bertranpetit, Jaume; Bosch, Elena; Bradley, Daniel G.; Brede, Gaute; Cooper, Gillian; Côrte-Real, Helena B. S. M.; de Knijff, Peter; Decorte, Ronny; Dubrova, Yuri E.; Evgrafov, Oleg; Gilissen, Anja; Glisic, Sanja; Gölge, Mukaddes; Hill, Emmeline W.; Jeziorowska, Anna; Kalaydjieva, Luba; Kayser, Manfred; Kivisild, Toomas; Kravchenko, Sergey A.; Krumina, Astrida; Kučinskas, Vaidutis; Lavinha, João; Livshits, Ludmila A.; Malaspina, Patrizia; Maria, Syrrou; McElreavey, Ken; Meitinger, Thomas A.; Mikelsaar, Aavo-Valdur; Mitchell, R. John; Nafa, Khedoudja; Nicholson, Jayne; Nørby, Søren; Pandya, Arpita; Parik, Jüri; Patsalis, Philippos C.; Pereira, Luísa; Peterlin, Borut; Pielberg, Gerli; Prata, Maria João; Previderé, Carlo; Roewer, Lutz; Rootsi, Siiri; Rubinsztein, D. C.; Saillard, Juliette; Santos, Fabrício R.; Stefanescu, Gheorghe; Sykes, Bryan C.; Tolun, Aslihan; Villems, Richard; Tyler-Smith, Chris; Jobling, Mark A.

    2000-01-01

    Clinal patterns of autosomal genetic diversity within Europe have been interpreted in previous studies in terms of a Neolithic demic diffusion model for the spread of agriculture; in contrast, studies using mtDNA have traced many founding lineages to the Paleolithic and have not shown strongly clinal variation. We have used 11 human Y-chromosomal biallelic polymorphisms, defining 10 haplogroups, to analyze a sample of 3,616 Y chromosomes belonging to 47 European and circum-European populations. Patterns of geographic differentiation are highly nonrandom, and, when they are assessed using spatial autocorrelation analysis, they show significant clines for five of six haplogroups analyzed. Clines for two haplogroups, representing 45% of the chromosomes, are continentwide and consistent with the demic diffusion hypothesis. Clines for three other haplogroups each have different foci and are more regionally restricted and are likely to reflect distinct population movements, including one from north of the Black Sea. Principal-components analysis suggests that populations are related primarily on the basis of geography, rather than on the basis of linguistic affinity. This is confirmed in Mantel tests, which show a strong and highly significant partial correlation between genetics and geography but a low, nonsignificant partial correlation between genetics and language. Genetic-barrier analysis also indicates the primacy of geography in the shaping of patterns of variation. These patterns retain a strong signal of expansion from the Near East but also suggest that the demographic history of Europe has been complex and influenced by other major population movements, as well as by linguistic and geographic heterogeneities and the effects of drift. PMID:11078479

  6. Effects of climate warming and declining species richness in grassland model ecosystems: acclimation of CO2 fluxes

    Directory of Open Access Journals (Sweden)

    A. S. Kowalski

    2006-09-01

    Full Text Available To study the effects of warming and declining species richness on the carbon balance of grassland communities, model ecosystems containing one, three or nine species were exposed to ambient and elevated (ambient +3°C air temperature. In this paper, we analyze measured ecosystem CO2 fluxes to test whether ecosystem photosynthesis and respiration had acclimated to warming after 28 months of continuous heating, and whether the degree of acclimation depended on species richness. At first sight, we found no signs of acclimation in photosynthesis or respiration. However, because plant cover was significantly higher in the heated treatment, normalization for plant cover revealed down-regulation of both photosynthesis and respiration. Although CO2 fluxes were larger in communities with higher species richness, species richness did not affect the degree of acclimation to warming. These results imply that models need to take into account thermal acclimation to simulate photosynthesis and respiration in a warmer world.

  7. Effects of Acclimation on Poststocking Dispersal and Physiological Condition of Age-1 Pallid Sturgeon

    Energy Technology Data Exchange (ETDEWEB)

    Oldenburg, Eric W.; Guy, Christopher S.; Cureton, Eli S.; Webb, Molly H.; Gardner, William M.

    2011-03-28

    A propagation program for pallid sturgeon Scaphirhynchus albus in the upper Missouri River was implemented by the U. S. Fish and Wildlife Service in 1997. Preliminary research indicated that many hatchery-reared pallid sturgeon were experiencing significant downstream poststocking dispersal, negatively affecting their recruitment. Therefore, the objective of this study was to evaluate the effects of acclimation to flow and site-specific physicochemical water conditions on poststocking dispersal and physiological condition of age-1 pallid sturgeon. Fish from three acclimation treatments were radio-tagged, released at two locations (Missouri River and Marias River), and monitored using passive telemetry stations. Marias treatment was acclimated to flow and site-specific physicochemical conditions, Bozeman treatment was acclimated to flow only, and traditional treatment had no acclimation (reared under traditional protocol). During both years fish released in the Missouri River dispersed less than fish released in the Marias River. In 2005, Marias treatment dispersed less and nearly twice as many fish remained in the Missouri River reach than traditional treatment. In 2006, pallid sturgeon dispersed similarly among treatments and fish remaining in the Missouri River reach were similar among all treatments. Differences in poststocking dispersal between years may be related to fin curl. Fin curl was present in all fish in 2005 and 27% of the fish in 2006. Pallid sturgeon from all treatments in both years had a greater affinity for the lower reaches of the Missouri River than the upper reaches. Thus, habitat at release site influenced poststocking dispersal more than acclimation treatment. No difference was observed in relative growth rate among treatments in 2006. However, acclimation to flow (i.e., exercise conditioning) may reduce liver fat content. Acclimation conditions used in this study may not benefit pallid sturgeon unless physiological maladies are present

  8. Toxaphene detoxification and acclimation in Daphnia magna: do cytochrome P-450 enzymes play a role?

    Science.gov (United States)

    Kashian, Donna R

    2004-01-01

    Toxaphene is a persistent environmental contaminant that has been shown to alter male production in Daphnia magna and to induce P-450 activity in mammals. Cytochrome P-450-mediated metabolism may lead to xenobiotic detoxification resulting in acclimation. To determine if D. magna acclimate to toxaphene via P-450 pathways, chronic and acute toxicity tests were conducted with D. magna exposed to toxaphene in the presence and absence of piperonyl butoxide (PBO), an inhibitor of cytochrome P-450 enzymes. Toxaphene exposure increased male production in acute but not chronic assays, indicating that D. magna may acclimate to chronic toxaphene exposure. Upon co-administration of toxaphene and PBO in chronic tests, D. magna exhibited a decline in growth rate, fecundity and survival. The observed toxaphene acclimation in chronic tests, along with its increased toxicity in the presence of a P-450 suppressor, suggests that P-450 enzymes may contribute to detoxification and subsequent acclimation of D. magna to chronic toxaphene exposure. Additional chronic toxicity tests indicated that toxaphene acclimation occurs between 7 and 12 days following initial exposure, at which time sex determination is no longer affected. Thus, sublethal toxaphene toxicity effects such as reproductive impairments may be detectable with acute but not chronic tests, potentially due to the upregulation of P-450 isozymes.

  9. Physiological and morphological acclimation to height in cupressoid leaves of 100-year-old Chamaecyparis obtusa.

    Science.gov (United States)

    Shiraki, Ayumi; Azuma, Wakana; Kuroda, Keiko; Ishii, H Roaki

    2016-10-15

    Cupressoid (scale-like) leaves are morphologically and functionally intermediate between stems and leaves. While past studies on height acclimation of cupressoid leaves have focused on acclimation to the vertical light gradient, the relationship between morphology and hydraulic function remains unexplored. Here, we compared physiological and morphological characteristics between treetop and lower-crown leaves of 100-year-old Chamaecyparis obtusa Endl. trees (~27 m tall) to investigate whether height-acclimation compensates for hydraulic constraints. We found that physiological acclimation of leaves was determined by light, which drove the vertical gradient of evaporative demand, while leaf morphology and anatomy were determined by height. Compared with lower-crown leaves, treetop leaves were physiologically acclimated to water stress. Leaf hydraulic conductance was not affected by height, and this contributed to higher photosynthetic rates of treetop leaves. Treetop leaves had higher leaf area density and greater leaf mass per area, which increase light interception but could also decrease hydraulic efficiency. We inferred that transfusion tissue flanking the leaf vein, which was more developed in the treetop leaves, contributes to water-stress acclimation and maintenance of leaf hydraulic conductance by facilitating osmotic adjustment of leaf water potential and efficient water transport from xylem to mesophyll. Our findings may represent anatomical adaptation that compensates for hydraulic constraints on physiological function with increasing height.

  10. Branchial ionocyte organization and ion-transport protein expression in juvenile alewives acclimated to freshwater or seawater

    Science.gov (United States)

    Christensen, A.K.; Hiroi, J.; Schultz, E.T.; McCormick, S.D.

    2012-01-01

    The alewife (Alosa pseudoharengus) is a clupeid that undergoes larval and juvenile development in freshwater preceding marine habitation. The purpose of this study was to investigate osmoregulatory mechanisms in alewives that permit homeostasis in different salinities. To this end, we measured physiological, branchial biochemical and cellular responses in juvenile alewives acclimated to freshwater (0.5p.p.t.) or seawater (35.0p.p.t.). Plasma chloride concentration was higher in seawater-acclimated than freshwater-acclimated individuals (141mmoll -1 vs 134mmoll -1), but the hematocrit remained unchanged. In seawateracclimated individuals, branchial Na +/K +-ATPase (NKA) activity was higher by 75%. Western blot analysis indicated that the abundance of the NKA subunit and a Na+/K+/2Cl- cotransporter (NKCC1) were greater in seawater-acclimated individuals by 40% and 200%, respectively. NKA and NKCC1 were localized on the basolateral surface and tubular network of ionocytes in both acclimation groups. Immunohistochemical labeling for the cystic fibrosis transmembrane conductance regulator (CFTR) was restricted to the apical crypt of ionocytes in seawater-acclimated individuals, whereas sodium/hydrogen exchanger 3 (NHE3) labeling was present on the apical surface of ionocytes in both acclimation groups. Ionocytes were concentrated on the trailing edge of the gill filament, evenly distributed along the proximal 75% of the filamental axis and reduced distally. Ionocyte size and number on the gill filament were not affected by salinity; however, the number of lamellar ionocytes was significantly lower in seawater-acclimated fish. Confocal z-series reconstructions revealed that mature ionocytes in seawater-acclimated alewives occurred in multicellular complexes. These complexes might reduce paracellular Na + resistance, hence facilitating Na+ extrusion in hypo-osmoregulating juvenile alewives after seaward migration. ?? 2012. Published by The Company of Biologists Ltd.

  11. The temperature acclimation potential of tropical bryophytes.

    Science.gov (United States)

    Wagner, S; Zotz, G; Bader, M Y

    2014-01-01

    Bryophyte biomass and diversity in tropical moist forests decrease dramatically from higher altitudes towards the lowlands. High respiratory carbon losses at high temperatures may partly explain this pattern, if montane species are unable to acclimatise their metabolic rates to lowland temperatures. We transplanted ten bryophyte species from two altitudes (1200 and 500 m a.s.l.) to lower (warmer) altitudes (500 m and sea level) in Panama. We studied short-term temperature acclimation of CO2 exchange for 2.5 months, and survival and growth for 21 months following transplantation. Short-term acclimation did not occur, and on a longer time scale mortality was highest and growth lowest in the transplanted samples. A few transplanted samples of most species, however, survived the whole experiment and finished with growth rates similar to controls. This recovery of growth rate suggests temperature acclimation, in spite of no measurable metabolic changes in smaller random samples. This acclimation even compensated for shorter periods of CO2 uptake due to more rapid drying. Nevertheless, these species are not abundant in lowland forests, perhaps due to dispersal or establishment limitation. The apparent heterogeneity of the acclimation potential within species may allow populations to adapt locally and avoid being forced uphill under climatic warming.

  12. Impact of acclimation methods on microbial communities and performance of anaerobic fluidized bed membrane bioreactors

    KAUST Repository

    Labarge, Nicole

    2016-10-17

    An anaerobic fluidized bed membrane bioreactor (AFMBR) is a new and effective method for energy-efficient treatment of low strength wastewater, but the factors that affect performance are not well known. Different inocula and acclimation methods of the granular activated carbon (GAC) used in the reactor were examined here to determine their impact on chemical oxygen demand (COD) removal and microbial community composition of domestic wastewater-fed AFMBRs. AFMBRs inoculated with anaerobic digester sludge (D) or domestic wastewater (W) and fed domestic wastewater, or inoculated with a microbiologically diverse anaerobic bog sediment and acclimated using methanol (M), all produced the same COD removal of 63 ± 12% using a diluted wastewater feed (100 ± 21 mg L−1 COD). However, an AFMBR with GAC inoculated with anaerobic digester sludge and acclimated using acetate (A) showed significantly increased wastewater COD removal to 84 ± 6%. In addition, feeding the AFMBR with the M-acclimated GAC with an acetate medium for one week subsequently increased COD removal to 70 ± 6%. Microbial communities enriched on the GAC included Geobacter, sulfur-reducing bacteria, Syntrophaceae, and Chlorobiaceae, with reactor A having the highest relative abundance of Geobacter. These results showed that acetate was the most useful substrate for acclimation of GAC communities, and GAC harbors unique communities relative to those in the AFMBR influent and recirculated solution.

  13. Effects of heat acclimation on time perception.

    Science.gov (United States)

    Tamm, Maria; Jakobson, Ainika; Havik, Merle; Timpmann, Saima; Burk, Andres; Ööpik, Vahur; Allik, Jüri; Kreegipuu, Kairi

    2015-03-01

    Cognitive performance is impaired during prolonged exercise in hot environment compared to temperate conditions. These effects are related to both peripheral markers of heats stress and alterations in CNS functioning. Repeated-exposure to heat stress results in physiological adaptations, and therefore improvement in exercise capacity and cognitive functioning are observed. The objective of the current study was to clarify the factors contributing to time perception under heat stress and examine the effect of heat acclimation. 20 young healthy male subjects completed three exercise tests on a treadmill: H1 (at 60% VO(2)peak until exhaustion at 42°C), N (at 22°C; duration equal to H1) and H2 (walk until exhaustion at 42°C) following a 10-day heat acclimation program. Core temperature (T(C)) and heart rate (HR), ratings of perceived fatigue and exertion were obtained continuously during the exercise, and blood samples of hormones were taken before, during and after the exercise test for estimating the prolactin, growth hormone and cortisol response to acute exercise-heat stress. Interval production task was performed before, during and after the exercise test. Lower rate of rise in core temperature, heart rate, hormone response and subjective ratings indicated that the subjects had successfully acclimated. Before heat acclimation, significant distortions in produced intervals occurred after 60 minutes of exercise relative to pre-trial coefficients, indicating speeded temporal processing. However, this effect was absent after in acclimated subjects. Blood prolactin concentration predicted temporal performance in both conditions. Heat acclimation slows down the increase in physiological measures, and improvement in temporal processing is also evident. The results are explained within the internal clock model in terms of the pacemaker-accumulator functioning. Copyright © 2014 Elsevier B.V. All rights reserved.

  14. Characterization of Medicago populations under cold acclimation by ...

    African Journals Online (AJOL)

    SAM

    2014-07-02

    Jul 2, 2014 ... acclimation by morphological traits and microsatellite. (SSR) markers ... acclimation, which will encourage for a study of association between cold acclimation and molecular ... Phenotypic assessment can provide a direct and easy ...... cold stress in two contrasting varieties of rape seed (Brassica napus. L.).

  15. Embryonic developmental temperatures modulate thermal acclimation of performance curves in tadpoles of the frog Limnodynastes peronii.

    Directory of Open Access Journals (Sweden)

    Frank Seebacher

    Full Text Available Performance curves of physiological rates are not fixed, and determining the extent to which thermal performance curves can change in response to environmental signals is essential to understand the effect of climate variability on populations. The aim of this study was to determine whether and how temperatures experienced during early embryonic development affect thermal performance curves of later life history stages in the frog Limnodynastes peronii. We tested the hypotheses that a the embryonic environment affects mean trait values only; b temperature at which performance of tadpoles is maximal shifts with egg incubation temperatures so that performance is maximised at the incubation temperatures, and c incubation temperatures modulate the capacity for reversible acclimation in tadpoles. Growth rates were greater in warm (25°C compared to cold (15°C acclimated (6 weeks tadpoles regardless of egg developmental temperatures (15°C or 25°C, representing seasonal means. The breadth of the performance curve of burst locomotor performance (measured at 10, 15, 20, 25, and 30°C, representing annual range is greatest when egg developmental and acclimation temperatures coincide. The mode of the performance curves shifted with acclimation conditions and maximum performance was always at higher temperatures than acclimation conditions. Performance curves of glycolytic (lactate dehydrogenase activities and mitochondrial (citrate synthase and cytochrome c oxidase enzymes were modulated by interactions between egg incubation and acclimation temperatures. Lactate dehydrogenase activity paralleled patterns seen in burst locomotor performance, but oxygen consumption rates and mitochondrial enzyme activities did not mirror growth or locomotor performance. We show that embryonic developmental conditions can modulate performance curves of later life-history stages, thereby conferring flexibilty to respond to environmental conditions later in life.

  16. Molecular biology of cyanobacterial salt acclimation.

    Science.gov (United States)

    Hagemann, Martin

    2011-01-01

    High and changing salt concentrations represent major abiotic factors limiting the growth of microorganisms. During their long evolution, cyanobacteria have adapted to aquatic habitats with various salt concentrations. High salt concentrations in the medium challenge the cell with reduced water availability and high contents of inorganic ions. The basic mechanism of salt acclimation involves the active extrusion of toxic inorganic ions and the accumulation of compatible solutes, including sucrose, trehalose, glucosylglycerol, and glycine betaine. The kinetics of these physiological processes has been exceptionally well studied in the model Synechocystis 6803, leading to the definition of five subsequent phases in reaching a new salt acclimation steady state. Recent '-omics' technologies using the advanced model Synechocystis 6803 have revealed a comprehensive picture of the dynamic process of salt acclimation involving the differential expression of hundreds of genes. However, the mechanisms involved in sensing specific salt stress signals are not well resolved. In the future, analysis of cyanobacterial salt acclimation will be directed toward defining the functions of the many unknown proteins upregulated in salt-stressed cells, identifying specific salt-sensing mechanisms, using salt-resistant strains of cyanobacteria for the production of bioenergy, and applying cyanobacterial stress genes to improve the salt tolerance of sensitive organisms.

  17. Effects of climate warming and declining species richness in grassland model ecosystems: acclimation of CO2 fluxes

    Directory of Open Access Journals (Sweden)

    S. Vicca

    2007-01-01

    Full Text Available To study the effects of warming and declining species richness on the carbon balance of grassland communities, model ecosystems containing one, three or nine species were exposed to ambient and elevated (ambient +3°C air temperature. In this paper, we analyze measured ecosystem CO2 fluxes to test whether ecosystem photosynthesis and respiration had acclimated to warming after 28 months of continuous heating, and whether the degree of acclimation depended on species richness. In order to test whether acclimation occurred, short term temperature response curves were established for all communities in both treatments. At similar temperatures, lower flux rates in the heated communities as compared to the unheated communities would indicate thermal acclimation. Because plant cover was significantly higher in the heated treatment, we normalized the data for plant cover. Subsequently, down-regulation of both photosynthesis and respiration was observed. Although CO2 fluxes were larger in communities with higher species richness, species richness did not affect the degree of acclimation to warming. These results imply that models need to take thermal acclimation into account to simulate photosynthesis and respiration in a warmer world.

  18. Mitochondrial acclimation capacities to ocean warming and acidification are limited in the antarctic Nototheniid Fish, Notothenia rossii and Lepidonotothen squamifrons.

    Science.gov (United States)

    Strobel, Anneli; Graeve, Martin; Poertner, Hans O; Mark, Felix C

    2013-01-01

    Antarctic notothenioid fish are characterized by their evolutionary adaptation to the cold, thermostable Southern Ocean, which is associated with unique physiological adaptations to withstand the cold and reduce energetic requirements but also entails limited compensation capacities to environmental change. This study compares the capacities of mitochondrial acclimation to ocean warming and acidification between the Antarctic nototheniid Notothenia rossii and the sub-Antarctic Lepidonotothen squamifrons, which share a similar ecology, but different habitat temperatures. After acclimation of L. squamifrons to 9°C and N. rossii to 7°C (normocapnic/hypercapnic, 0.2 kPa CO2/2000 ppm CO2) for 4-6 weeks, we compared the capacities of their mitochondrial respiratory complexes I (CI) and II (CII), their P/O ratios (phosphorylation efficiency), proton leak capacities and mitochondrial membrane fatty acid compositions. Our results reveal reduced CII respiration rates in warm-acclimated L. squamifrons and cold hypercapnia-acclimated N. rossii. Generally, L. squamifrons displayed a greater ability to increase CI contribution during acute warming and after warm-acclimation than N. rossii. Membrane unsaturation was not altered by warm or hypercapnia-acclimation in both species, but membrane fatty acids of warm-acclimated L. squamifrons were less saturated than in warm normocapnia-/hypercapnia-acclimated N. rossii. Proton leak capacities were not affected by warm or hypercapnia-acclimation of N. rossii. We conclude that an acclimatory response of mitochondrial capacities may include higher thermal plasticity of CI supported by enhanced utilization of anaplerotic substrates (via oxidative decarboxylation reactions) feeding into the citrate cycle. L. squamifrons possesses higher relative CI plasticities than N. rossii, which may facilitate the usage of energy efficient NADH-related substrates under conditions of elevated energy demand, possibly induced by ocean warming and

  19. Mitochondrial acclimation capacities to ocean warming and acidification are limited in the antarctic Nototheniid Fish, Notothenia rossii and Lepidonotothen squamifrons.

    Directory of Open Access Journals (Sweden)

    Anneli Strobel

    Full Text Available Antarctic notothenioid fish are characterized by their evolutionary adaptation to the cold, thermostable Southern Ocean, which is associated with unique physiological adaptations to withstand the cold and reduce energetic requirements but also entails limited compensation capacities to environmental change. This study compares the capacities of mitochondrial acclimation to ocean warming and acidification between the Antarctic nototheniid Notothenia rossii and the sub-Antarctic Lepidonotothen squamifrons, which share a similar ecology, but different habitat temperatures. After acclimation of L. squamifrons to 9°C and N. rossii to 7°C (normocapnic/hypercapnic, 0.2 kPa CO2/2000 ppm CO2 for 4-6 weeks, we compared the capacities of their mitochondrial respiratory complexes I (CI and II (CII, their P/O ratios (phosphorylation efficiency, proton leak capacities and mitochondrial membrane fatty acid compositions. Our results reveal reduced CII respiration rates in warm-acclimated L. squamifrons and cold hypercapnia-acclimated N. rossii. Generally, L. squamifrons displayed a greater ability to increase CI contribution during acute warming and after warm-acclimation than N. rossii. Membrane unsaturation was not altered by warm or hypercapnia-acclimation in both species, but membrane fatty acids of warm-acclimated L. squamifrons were less saturated than in warm normocapnia-/hypercapnia-acclimated N. rossii. Proton leak capacities were not affected by warm or hypercapnia-acclimation of N. rossii. We conclude that an acclimatory response of mitochondrial capacities may include higher thermal plasticity of CI supported by enhanced utilization of anaplerotic substrates (via oxidative decarboxylation reactions feeding into the citrate cycle. L. squamifrons possesses higher relative CI plasticities than N. rossii, which may facilitate the usage of energy efficient NADH-related substrates under conditions of elevated energy demand, possibly induced by ocean

  20. Light acclimation in Porphyridium purpureum (Rhodophyta): Growth, photosynthesis, and phycobilisomes

    Energy Technology Data Exchange (ETDEWEB)

    Levy, I.; Gantt, E. (Smithsonian Institution, WA (USA))

    1988-12-01

    Acclimation to three photon flux densities 10, 35, 180 {mu}E{center dot}m{sup {minus}2}{center dot}s{sup {minus}1} was determined in laboratory cultures of Porphyridium purpureum Bory, Drew and Ross. Cultures grown at low, medium, and high PPFDs had compensation points of <3, 6, and 20 {mu}E{center dot}m{sup {minus}2}{center dot}s{sup {minus}1}, respectively, and saturating irradiances in the initial log phase of 90, 115, 175 {mu}E{center dot}m{sup {minus}2}{center dot}s{sup {minus}1} and up to 240 {mu}E{center dot}m{sup {minus}2}{center dot}s{sup {minus}1} in late log phase. High light cells had the smallest photosynthetic unit size (phycobiliproteins plus chlorophyll), the highest photosynthetic capacity, and the highest growth rates. Photosystem I reaction centers (P700) per cell remained proportional to chlorophyll at ca. 110 chl/P700. However, phycobiliprotein content decreased as did the phycobilisome number (ca. 50%) in high light cells, whereas the phycobilisome size remained the same as in medium and low light cells. We concluded that acclimation of this red alga to varied PPFDs was manifested by the plasticity of the photosystem II antennae with little, if any, affect noted on photosystem I.

  1. Thermoregulation in hypergravity-acclimated rats

    Science.gov (United States)

    Monson, Conrad B.; Patterson, Susan L.; Horowitz, John M.; Oyama, Jiro

    1989-01-01

    The effect of acclimation to hypergravity on thermoregulatory responses of rats was determined by comparing data on core temperature, T(c), tail temperature, and O2 consumption in rats raised at 1 G (C) and at 2.1 G. It was found that, when C rats were exposed to an ambient temperature of 9 C concurrently with exposure to 2.1 G, the T(c) fell by about 6 C, while in rats acclimated to 2.1 G, the T(c) fell only by 1 C. Results of O2 consumption measurements showed that C rats exposed simultaneously to cold and hypergravity were not activating their thermogenic mechanism sufficiently to prevent a fall in T(c). In other experiments, rats acclimated to either 1 or 2.1 G were found to lack the ability to maintain their T(c) when exposed to a 5.8-G field or when cold-stressed at 1 G for extended times.

  2. Salicylic acid and heat acclimation pretreatment protects Laminaria japonica sporophyte (Phaeophyceae) from heat stress

    Science.gov (United States)

    Zhou, Bin; Tang, Xuexi; Wang, You

    2010-07-01

    Possible mediatory roles of heat acclimation and salicylic acid in protecting the sporophyte of marine macroalga Laminaria japonica (Phaeophyceae) from heat stress were studied. Heat stress resulted in oxidative injury in the kelp blades. Under heat stress significant accumulation of hydrogen peroxide (H2O2) and malonaldehyde (MDA), a membrane lipid peroxidation product, and a drastic decrease in chlorophyll a content were recorded. Activity of the enzymatic antioxidant system was drastically affected by heat stress. The activity of superoxide dismutase (SOD) was significantly increased while peroxidase (POD), catalase (CAT) and glutathione peroxidase (GPX) were greatly inhibited and, simultaneously, phenylalanine ammonia-lyase was activated while polyphenol oxidase (PPO) was inhibited. Both heat acclimation pretreatment and exogenous application of salicylic acid alleviated oxidative damage in kelp blades. Blades receiving heat acclimation pretreatment and exogenous salicylic acid prior to heat stress exhibited a reduced increase in H2O2 and MDA content, and a lower reduction in chlorophyll a content. Pretreatment with heat acclimation and salicylic acid elevated activities of SOD, POD, CAT, GPX and PPO. Considering these results collectively, we speculate that the inhibition of antioxidant enzymes is a possible cause of the heat-stress-induced oxidative stress in L. japonica, and enhanced thermotolerance may be associated, at least in part, with the elevated activity of the enzymatic antioxidant system.

  3. Thermal Acclimation of Respiration and Photosynthesis in the Marine Macroalga Gracilaria lemaneiformis (Gracilariales, Rhodophyta).

    Science.gov (United States)

    Zou, Dinghui; Gao, Kunshan

    2013-02-01

    The responses of respiration and photosynthesis to temperature fluctuations in marine macroalgae have the potential to significantly affect coastal carbon fluxes and sequestration. In this study, the marine red macroalga Gracilaria lemaneiformis was cultured at three different temperatures (12, 19, and 26°C) and at high- and low-nitrogen (N) availability, to investigate the acclimation potential of respiration and photosynthesis to temperature change. Measurements of respiratory and photosynthetic rates were made at five temperatures (7°C-33°C). An instantaneous change in temperature resulted in a change in the rates of respiration and photosynthesis, and the temperature sensitivities (i.e., the Q10 value) for both the metabolic processes were lower in 26°C-grown algae than 12°C- or 19°C-grown algae. Both respiration and photosynthesis acclimated to long-term changes in temperature, irrespective of the N availability under which the algae were grown; respiration displayed strong acclimation, whereas photosynthesis only exhibited a partial acclimation response to changing growth temperatures. The ratio of respiration to gross photosynthesis was higher in 12°C-grown algae, but displayed little difference between the algae grown at 19°C and 26°C. We propose that it is unlikely that respiration in G. lemaneiformis would increase significantly with global warming, although photosynthesis would increase at moderately elevated temperatures.

  4. Effects of cadmium exposure on the gill proteome of Cottus gobio: Modulatory effects of prior thermal acclimation

    Energy Technology Data Exchange (ETDEWEB)

    Dorts, Jennifer, E-mail: jennifer.dorts@unamur.be [Research Unit in Environmental and Evolutionary Biology (URBE), University of Namur, Rue de Bruxelles 61, B-5000 Namur (Belgium); Kestemont, Patrick [Research Unit in Environmental and Evolutionary Biology (URBE), University of Namur, Rue de Bruxelles 61, B-5000 Namur (Belgium); Thézenas, Marie-Laetitia; Raes, Martine [Research Unit in Cell Biology (URBC) (NARILIS), University of Namur, Rue de Bruxelles 61, B-5000 Namur (Belgium); Silvestre, Frédéric [Research Unit in Environmental and Evolutionary Biology (URBE), University of Namur, Rue de Bruxelles 61, B-5000 Namur (Belgium)

    2014-09-15

    Highlights: • Fish acclimated to elevated temperature were subsequently exposed to cadmium. • Interaction of both stressors on LDH activity and protein expression was complex. • Both stressors have opposite effects at branchial protein expression level. • Proteins belonging to the same functional class exhibited differing responses. • Prior acclimation to elevated temperature modulated the effects of cadmium exposure. - Abstract: Temperature and trace metals are common environmental stressors, and their importance is increasing due to global climate change and anthropogenic pollution. The aim of the present study was to investigate whether acclimation to elevated temperature affects the response of the European bullhead (Cottus gobio) to subsequent cadmium (Cd) exposure by using enzymatic and proteomic approaches. Fish acclimated to 15 (standard temperature), 18 or 21 °C for 28 days were exposed to 1 mg Cd/L for 4 days at the respective acclimation temperature. First, exposure to Cd significantly decreased the activity of the lactate dehydrogenase (LDH) in gills of fish acclimated to 15 or 18 °C. However, an acclimation to 21 °C suppressed the inhibitory effect of Cd. Second, using a proteomic analysis by 2D-DIGE, we observed that thermal acclimation was the first parameter affecting the protein expression profile in gills of C. gobio, while subsequent Cd exposure seemed to attenuate this temperature effect. Moreover, our results showed opposite effects of these two environmental stressors at protein expression level. From the 52 protein spots displaying significant interaction effects of temperature and Cd exposure, a total of 28 different proteins were identified using nano LC–MS/MS and the Peptide and Protein Prophet algorithms of Scaffold software. The identified differentially expressed proteins can be categorized into diverse functional classes, related to protein turnover, folding and chaperoning, metabolic process, ion transport, cell

  5. Limited capacity for developmental thermal acclimation in three tropical wrasses

    Science.gov (United States)

    Motson, K.; Donelson, J. M.

    2017-06-01

    For effective conservation and management of marine systems, it is essential that we understand the biological impacts of and capacity for acclimation to increased ocean temperatures. This study investigated for the first time the effects of developing in projected warmer ocean conditions in the tropical wrasse species: Halichoeres melanurus, Halichoeres miniatus and Thalassoma amblycephalum. New recruits were reared for 11 weeks in control (29 °C) and +2 °C (31 °C) temperature treatments, consistent with predicted increases in sea surface temperature by 2100. A broad range of key attributes and performance parameters was tested, including aerobic metabolism, swimming ability, burst escape performance and physical condition. Response latency of burst performance was the only performance parameter in which evidence of beneficial thermal developmental acclimation was found, observed only in H. melanurus. Generally, development in the +2 °C treatment came at a significant cost to all species, resulting in reduced growth and physical condition, as well as metabolic and swimming performance relative to controls. Development in +2 °C conditions exacerbated the effects of warming on aerobic metabolism and swimming ability, compared to short-term warming effects. Burst escape performance parameters were only mildly affected by development at +2 °C, with non-locomotor performance (response latency) showing greater thermal sensitivity than locomotor performance parameters. These results indicate that the effects of future climate change on tropical wrasses would be underestimated with short-term testing. This study highlights the importance of holistic, longer-term developmental experimental approaches, with warming found to yield significant, species-specific responses in all parameters tested.

  6. Influence of arbuscular mycorrhizal colonization on whole-plant respiration and thermal acclimation of tropical tree seedlings.

    Science.gov (United States)

    Fahey, Catherine; Winter, Klaus; Slot, Martijn; Kitajima, Kaoru

    2016-02-01

    Symbiotic arbuscular mycorrhizal fungi (AMF) are ubiquitous in tropical forests. AMF play a role in the forest carbon cycle because they can increase nutrient acquisition and biomass of host plants, but also incur a carbon cost to the plant. Through their interactions with their host plants they have the potential to affect how plants respond to environmental perturbation such as global warming. Our objective was to experimentally determine how plant respiration rates and responses to warmer environment are affected by AMF colonization in seedlings of five tropical tree species at the whole plant level. We evaluated the interaction between AMF colonization and temperature on plant respiration against four possible outcomes; acclimation does or does not occur regardless of AMF, or AMF can increase or decrease respiratory acclimation. Seedlings were inoculated with AMF spores or sterilized inoculum and grown at ambient or elevated nighttime temperature. We measured whole plant and belowground respiration rates, as well as plant growth and biomass allocation. There was an overall increase in whole plant, root, and shoot respiration rate with AMF colonization, whereas temperature acclimation varied among species, showing support for three of the four possible responses. The influence of AMF colonization on growth and allocation also varied among plant species. This study shows that the effect of AMF colonization on acclimation differs among plant species. Given the cosmopolitan nature of AMF and the importance of plant acclimation for predicting climate feedbacks a better understanding of the patterns and mechanisms of acclimation is essential for improving predictions of how climate warming may influence vegetation feedbacks.

  7. Acclimation to constant and variable temperatures in plethodontid salamanders--I. Rates of oxygen consumption.

    Science.gov (United States)

    Feder, M E

    1985-01-01

    In preliminary experiments, salamanders of three species (Desmognathus ochrophaeus, Plethodon cinereus and Plethodon jordani) required 5-11 days to complete metabolic acclimation to a constant warm temperature; the rate of oxygen consumption (VO2) decreased 16-28% during acclimation. Unfed animals of each species underwent cyclic exposure to 5 and 21 degrees C at three different cycle periods (12 hr, 4-5 days, 51 days), or constant exposure to 14 degrees C for 102 days. The experimental treatments significantly affected the VO2 measured at 5, 14, 17.5 and 21 degrees C. The direction and magnitude of the acclimatory effects upon VO2 were inconsistent among species and among experimental temperatures, and resulted in little energy saving. The VO2 during exposure to cyclic temperatures averaged only 83% of that during preliminary experiments, perhaps as a response to starvation.

  8. Biophysical consequences of photosynthetic temperature acclimation for climate

    Science.gov (United States)

    Smith, Nicholas G.; Lombardozzi, Danica; Tawfik, Ahmed; Bonan, Gordon; Dukes, Jeffrey S.

    2017-03-01

    Photosynthetic temperature acclimation is a commonly observed process that is increasingly being incorporated into Earth System Models (ESMs). While short-term acclimation has been shown to increase carbon storage in the future, it is uncertain whether acclimation will directly influence simulated future climate through biophysical mechanisms. Here, we used coupled atmosphere-biosphere simulations using the Community Earth System Model (CESM) to assess how acclimation-induced changes in photosynthesis influence global climate under present-day and future (RCP 8.5) conditions. We ran four 30 year simulations that differed only in sea surface temperatures and atmospheric CO2 (present or future) and whether a mechanism for photosynthetic temperature acclimation was included (yes or no). Acclimation increased future photosynthesis and, consequently, the proportion of energy returned to the atmosphere as latent heat, resulting in reduced surface air temperatures in areas and seasons where acclimation caused the biggest increase in photosynthesis. However, this was partially offset by temperature increases elsewhere, resulting in a small, but significant, global cooling of 0.05°C in the future, similar to that expected from acclimation-induced increases in future land carbon storage found in previous studies. In the present-day simulations, the photosynthetic response was not as strong and cooling in highly vegetated regions was less than warming elsewhere, leading to a net global increase in temperatures of 0.04°C. Precipitation responses were variable and rates did not change globally in either time period. These results, combined with carbon-cycle effects, suggest that models without acclimation may be overestimating positive feedbacks between climate and the land surface in the future.

  9. Thermal acclimation of leaf respiration of tropical trees and lianas: response to experimental canopy warming, and consequences for tropical forest carbon balance.

    Science.gov (United States)

    Slot, Martijn; Rey-Sánchez, Camilo; Gerber, Stefan; Lichstein, Jeremy W; Winter, Klaus; Kitajima, Kaoru

    2014-09-01

    Climate warming is expected to increase respiration rates of tropical forest trees and lianas, which may negatively affect the carbon balance of tropical forests. Thermal acclimation could mitigate the expected respiration increase, but the thermal acclimation potential of tropical forests remains largely unknown. In a tropical forest in Panama, we experimentally increased nighttime temperatures of upper canopy leaves of three tree and two liana species by on average 3 °C for 1 week, and quantified temperature responses of leaf dark respiration. Respiration at 25 °C (R25 ) decreased with increasing leaf temperature, but acclimation did not result in perfect homeostasis of respiration across temperatures. In contrast, Q10 of treatment and control leaves exhibited similarly high values (range 2.5-3.0) without evidence of acclimation. The decrease in R25 was not caused by respiratory substrate depletion, as warming did not reduce leaf carbohydrate concentration. To evaluate the wider implications of our experimental results, we simulated the carbon cycle of tropical latitudes (24°S-24°N) from 2000 to 2100 using a dynamic global vegetation model (LM3VN) modified to account for acclimation. Acclimation reduced the degree to which respiration increases with climate warming in the model relative to a no-acclimation scenario, leading to 21% greater increase in net primary productivity and 18% greater increase in biomass carbon storage over the 21st century. We conclude that leaf respiration of tropical forest plants can acclimate to nighttime warming, thereby reducing the magnitude of the positive feedback between climate change and the carbon cycle. © 2014 John Wiley & Sons Ltd.

  10. Forest trees filter chronic wind-signals to acclimate to high winds.

    Science.gov (United States)

    Bonnesoeur, Vivien; Constant, Thiéry; Moulia, Bruno; Fournier, Meriem

    2016-05-01

    Controlled experiments have shown that trees acclimate thigmomorphogenetically to wind-loads by sensing their deformation (strain). However, the strain regime in nature is exposed to a full spectrum of winds. We hypothesized that trees avoid overreacting by responding only to winds which bring information on local climate and/or wind exposure. Additionally, competition for light dependent on tree social status also likely affects thigmomorphogenesis. We monitored and manipulated quantitatively the strain regimes of 15 pairs of beech (Fagus sylvatica) trees of contrasting social status in an acclimated stand, and quantified the effects of these regimes on the radial growth over a vegetative season. Trees exposed to artificial bending, the intensity of which corresponds to the strongest wind-induced strains, enhanced their secondary growth by at least 80%. Surprisingly, this reaction was even greater - relatively - for suppressed trees than for dominant ones. Acclimated trees did not sense the different types of wind events in the same way. Daily wind speed peaks due to thermal winds were filtered out. Thigmomorphogenesis was therefore driven by intense storms. Thigmomorphogenesis is also likely to be involved in determining social status.

  11. Intraspecific variation in thermal acclimation of photosynthesis across a range of temperatures in a perennial crop

    Science.gov (United States)

    Zaka, Serge; Frak, Ela; Julier, Bernadette; Gastal, François; Louarn, Gaëtan

    2016-01-01

    Interest in the thermal acclimation of photosynthesis has been stimulated by the increasing relevance of climate change. However, little is known about intra-specific variations in thermal acclimation and its potential for breeding. In this article, we examined the difference in thermal acclimation between alfalfa (Medicago sativa) cultivars originating from contrasting origins, and sought to analyze the mechanisms in play. A series of experiments was carried out at seven growth temperatures between 5 and 35 °C using four cultivars from temperate and Mediterranean origin. Leaf traits, the photosynthetic rate at 25 °C (A40025), the photosynthetic rate at optimal temperature (A400opt), the thermal optimum of photosynthesis (Topt), and the photosynthetic parameters from the Farqhuar model were determined. Irrespective of cultivar origin, a clear shift in the temperature responses of photosynthesis was observed as a function of growth temperature, affecting thermal optimum of photosynthesis, photosynthetic rate at optimal temperature and photosynthetic rate at 25 °C. For both cultivars, Topt values increased linearly in leaves grown between 5 and 35 °C. Relative homeostasis of A40025 and A400opt was found between 10 °C and 30 °C growth temperatures, but sharp declines were recorded at 5 and 35 °C. This homeostasis was achieved in part through modifications to leaf nitrogen content, which increased at extreme temperatures. Significant changes were also recorded regarding nitrogen partitioning in the photosynthetic apparatus and in the temperature dependence of photosynthetic parameters. The cultivars differed only in terms of the temperature response of photosynthetic parameters, with Mediterranean genotypes displaying a greater sensitivity of the maximum rate of Rubisco carboxylation to elevated temperatures. It was concluded that intra-specific variations in the temperature acclimation of photosynthesis exist among alfalfa cultivars, but that

  12. Heat acclimation and physical training adaptations of young women using different contraceptive hormones.

    Science.gov (United States)

    Armstrong, Lawrence E; Maresh, Carl M; Keith, Nicole R; Elliott, Tabatha A; Vanheest, Jaci L; Scheett, Timothy P; Stoppani, James; Judelson, Daniel A; De Souza, Mary Jane

    2005-05-01

    Although endogenous and exogenous steroid hormones affect numerous physiological processes, the interactions of reproductive hormones, chronic exercise training, and heat acclimation are unknown. This investigation evaluated the responses and adaptations of 36 inactive females [age 21 +/- 3 (SD) yr] as they undertook a 7- to 8-wk program [heat acclimation and physical training (HAPT)] of indoor heat acclimation (90 min/day, 3 days/wk) and outdoor physical training (3 days/wk) while using either an oral estradiol-progestin contraceptive (ORAL, n = 15), a contraceptive injection of depot medroxyprogesterone acetate (DEPO, n = 7), or no contraceptive (EU-OV, n = 14; control). Standardized physical fitness and exercise-heat tolerance tests (36.5 degrees C, 37% relative humidity), administered before and after HAPT, demonstrated that the three subject groups successfully (P muscular endurance (i.e., sit-ups, push-ups, 4.6-km run time) and body composition characteristics. The stress of HAPT did not disrupt the menstrual cycle length/phase characteristics, ovulation, or plasma hormone concentrations of EU-OV. No between-group differences (P > 0.05) existed for rectal and skin temperatures or metabolic, cardiorespiratory, muscular endurance, or body composition variables. A significant difference post-HAPT in the onset temperature of local sweating, ORAL (37.2 +/- 0.4 degrees C) vs. DEPO (37.7 +/- 0.2 degrees C), suggested that steroid hormones influenced this adaptation. In summary, virtually all adaptations of ORAL and DEPO were similar to EU-OV, suggesting that exogenous reproductive hormones neither enhanced nor impaired the ability of women to complete 7-8 wk of strenuous physical training and heat acclimation.

  13. Effect of neonatal or adult heat acclimation on testicular and epididymal morphometry and sperm production in rats.

    Science.gov (United States)

    Kurowicka, B; Dietrich, G J; Kotwica, G

    2015-03-01

    The accessory gland weight, testicular and epididymal morphometry and sperm production were analyzed in four groups of rats housed at 20 or 34°C: (1) control rats (CR) kept at 20°C from birth to day 90; (2) adult heat-acclimated rats (AHA) kept at 20°C from birth to day 45 followed by 34°C to day 90; (3) neonatal heat-acclimated rats (NHA) kept at 34°C from birth to day 90 and (4) de-acclimated rats (DA) kept at 34°C from birth to day 45 followed by 20°C to day 90. In NHA and DA rats, accessory gland weight was higher than in controls. Despite the lack of differences in testicular and epididymal morphometry, curvilinear velocity of spermatozoa was lower in the NHA group compared to controls. Areas of seminiferous tubules were lower in the DA than in CR and NHA groups, however, sperm concentration and motility were not affected by the treatment in this group. In AHA rats, epithelium of approximately 20% of seminiferous tubules was degenerated and Sertoli cell number was lower in the remaining tubules. In contrast to sperm motility, epididymal duct area, area of the duct occupied by spermatozoa and cauda epididymis sperm concentration were lower in AHA rats than in the other groups. In conclusion, neonatal heat acclimation did not affect the testicular morphometry and epididymal sperm concentration, suggesting adjustment to high ambient temperature. On the contrary, adult heat acclimation of rats affected the examined parameters, leading to decreased sperm concentration.

  14. Salt acclimation of cyanobacteria and their application in biotechnology.

    Science.gov (United States)

    Pade, Nadin; Hagemann, Martin

    2014-12-29

    The long evolutionary history and photo-autotrophic lifestyle of cyanobacteria has allowed them to colonize almost all photic habitats on Earth, including environments with high or fluctuating salinity. Their basal salt acclimation strategy includes two principal reactions, the active export of ions and the accumulation of compatible solutes. Cyanobacterial salt acclimation has been characterized in much detail using selected model cyanobacteria, but their salt sensing and regulatory mechanisms are less well understood. Here, we briefly review recent advances in the identification of salt acclimation processes and the essential genes/proteins involved in acclimation to high salt. This knowledge is of increasing importance because the necessary mass cultivation of cyanobacteria for future use in biotechnology will be performed in sea water. In addition, cyanobacterial salt resistance genes also can be applied to improve the salt tolerance of salt sensitive organisms, such as crop plants.

  15. Salt Acclimation of Cyanobacteria and Their Application in Biotechnology

    Directory of Open Access Journals (Sweden)

    Nadin Pade

    2014-12-01

    Full Text Available The long evolutionary history and photo-autotrophic lifestyle of cyanobacteria has allowed them to colonize almost all photic habitats on Earth, including environments with high or fluctuating salinity. Their basal salt acclimation strategy includes two principal reactions, the active export of ions and the accumulation of compatible solutes. Cyanobacterial salt acclimation has been characterized in much detail using selected model cyanobacteria, but their salt sensing and regulatory mechanisms are less well understood. Here, we briefly review recent advances in the identification of salt acclimation processes and the essential genes/proteins involved in acclimation to high salt. This knowledge is of increasing importance because the necessary mass cultivation of cyanobacteria for future use in biotechnology will be performed in sea water. In addition, cyanobacterial salt resistance genes also can be applied to improve the salt tolerance of salt sensitive organisms, such as crop plants.

  16. Salt Acclimation of Cyanobacteria and Their Application in Biotechnology

    OpenAIRE

    Nadin Pade; Martin Hagemann

    2014-01-01

    The long evolutionary history and photo-autotrophic lifestyle of cyanobacteria has allowed them to colonize almost all photic habitats on Earth, including environments with high or fluctuating salinity. Their basal salt acclimation strategy includes two principal reactions, the active export of ions and the accumulation of compatible solutes. Cyanobacterial salt acclimation has been characterized in much detail using selected model cyanobacteria, but their salt sensing and regulatory mechanis...

  17. Effects of acclimation to human interaction on performance, temperament, physiological responses, and pregnancy rates of Brahman-crossbred cows.

    Science.gov (United States)

    Cooke, R F; Arthington, J D; Araujo, D B; Lamb, G C

    2009-12-01

    The objective of this study was to evaluate, over 2 consecutive years, the effects of acclimation to human interaction on performance, temperament, plasma concentrations of hormones and metabolites, and pregnancy rates of Brahman-crossbred cows. A total of 160 Braford and 235 Brahman x British cows were assigned to the 2-yr study. Approximately 45 d after weaning (August 2006) in yr 1, cows were evaluated for BW, BCS, and temperament (chute score, pen score, and exit velocity), stratified by these measurements in addition to breed and age, and randomly allocated to 14 groups (Braford = 8; Brahman x British = 6). Groups were randomly assigned to the control or acclimation treatment. In yr 2, cows were reevaluated within 45 d after weaning (August 2007) for BW, BCS, and temperament, stratified, and divided into 14 groups similarly as in yr 1, but in such a way that cows received the same treatment assigned in yr 1. Cows were acclimated to human interaction from August to January, and the acclimation process consisted of the same person visiting groups twice weekly and offering approximately 0.05 kg of range cubes per cow (as-fed basis). In January of both years, cow temperament, BW, and BCS were reassessed and cows were exposed to a 90-d breeding season. Blood samples were collected at the beginning of the acclimation period (August) and breeding season (January) for determination of plasma cortisol, IGF-I, and acute phase proteins. A treatment x breed interaction was detected during yr 1 (P < 0.01) for pregnancy analysis because acclimated Braford cows conceived earlier and at a greater percentage (P < 0.01) compared with control cows. According to values obtained at the beginning of breeding and pooled across treatments and breeds, IGF-I concentrations and BCS affected quadratically (P < 0.05), and concentrations of ceruloplasmin and haptoglobin decreased linearly (P < 0.05), the probability of pregnancy during both years. Temperament and cortisol concentrations

  18. Foliar temperature acclimation reduces simulated carbon sensitivity to climate

    Science.gov (United States)

    Smith, Nicholas G.; Malyshev, Sergey L.; Shevliakova, Elena; Kattge, Jens; Dukes, Jeffrey S.

    2016-04-01

    Plant photosynthesis and respiration are the largest carbon fluxes between the terrestrial biosphere and the atmosphere, and their parameterizations represent large sources of uncertainty in projections of land carbon uptake in Earth system models (ESMs). The incorporation of temperature acclimation of photosynthesis and foliar respiration, commonly observed processes, into ESMs has been proposed as a way to reduce this uncertainty. Here we show that, across 15 flux tower sites spanning multiple biomes at various locations worldwide (10° S-67° N), acclimation parameterizations improve a model's ability to reproduce observed net ecosystem exchange of CO2. This improvement is most notable in tropical biomes, where photosynthetic acclimation increased model performance by 36%. The consequences of acclimation for simulated terrestrial carbon uptake depend on the process, region and time period evaluated. Globally, including acclimation has a net effect of increasing carbon assimilation and storage, an effect that diminishes with time, but persists well into the future. Our results suggest that land models omitting foliar temperature acclimation are likely to overestimate the temperature sensitivity of terrestrial carbon exchange, thus biasing projections of future carbon storage and estimates of policy indicators such as the transient climate response to cumulative carbon emissions.

  19. Passive heat acclimation improves skeletal muscle contractility in humans.

    Science.gov (United States)

    Racinais, S; Wilson, M G; Périard, J D

    2017-01-01

    The aim of this study was to investigate the effect of repeated passive heat exposure (i.e., acclimation) on muscle contractility in humans. Fourteen nonheat-acclimated males completed two trials including electrically evoked twitches and voluntary contractions in thermoneutral conditions [Cool: 24°C, 40% relative humidity (RH)] and hot ambient conditions in the hyperthermic state (Hot: 44-50°C, 50% RH) on consecutive days in a counterbalanced order. Rectal temperature was ~36.5°C in Cool and was maintained at ~39°C throughout Hot. Both trials were repeated after 11 days of passive heat acclimation (1 h per day, 48-50°C, 50% RH). Heat acclimation decreased core temperature in Cool (-0.2°C, P heat acclimation improved skeletal muscle contractility as evidenced by an increase in evoked peak twitch amplitude both in Cool (20.5 ± 3.6 vs. 22.0 ± 4.0 N·m) and Hot (20.5 ± 4.7 vs. 22.0 ± 4.0 N·m) (+9%, P heat acclimation improves skeletal muscle contractile function during electrically evoked and voluntary muscle contractions of different intensities both in Cool and Hot. These results suggest that repeated heat exposure may have important implications to passively maintain or even improve muscle function in a variety of performance and clinical settings. Copyright © 2017 the American Physiological Society.

  20. Transgenerational acclimation of fishes to climate change and ocean acidification.

    Science.gov (United States)

    Munday, Philip L

    2014-01-01

    There is growing concern about the impacts of climate change and ocean acidification on marine organisms and ecosystems, yet the potential for acclimation and adaptation to these threats is poorly understood. Whereas many short-term experiments report negative biological effects of ocean warming and acidification, new studies show that some marine species have the capacity to acclimate to warmer and more acidic environments across generations. Consequently, transgenerational plasticity may be a powerful mechanism by which populations of some species will be able to adjust to projected climate change. Here, I review recent advances in understanding transgenerational acclimation in fishes. Research over the past 2 to 3 years shows that transgenerational acclimation can partially or fully ameliorate negative effects of warming, acidification, and hypoxia in a range of different species. The molecular and cellular pathways underpinning transgenerational acclimation are currently unknown, but modern genetic methods provide the tools to explore these mechanisms. Despite the potential benefits of transgenerational acclimation, there could be limitations to the phenotypic traits that respond transgenerationally, and trade-offs between life stages, that need to be investigated. Future studies should also test the potential interactions between transgenerational plasticity and genetic evolution to determine how these two processes will shape adaptive responses to environmental change over coming decades.

  1. Interaction with diurnal and circadian regulation results in dynamic metabolic and transcriptional changes during cold acclimation in Arabidopsis.

    Directory of Open Access Journals (Sweden)

    Carmen Espinoza

    Full Text Available In plants, there is a large overlap between cold and circadian regulated genes and in Arabidopsis, we have shown that cold (4°C affects the expression of clock oscillator genes. However, a broader insight into the significance of diurnal and/or circadian regulation of cold responses, particularly for metabolic pathways, and their physiological relevance is lacking. Here, we performed an integrated analysis of transcripts and primary metabolites using microarrays and gas chromatography-mass spectrometry. As expected, expression of diurnally regulated genes was massively affected during cold acclimation. Our data indicate that disruption of clock function at the transcriptional level extends to metabolic regulation. About 80% of metabolites that showed diurnal cycles maintained these during cold treatment. In particular, maltose content showed a massive night-specific increase in the cold. However, under free-running conditions, maltose was the only metabolite that maintained any oscillations in the cold. Furthermore, although starch accumulates during cold acclimation we show it is still degraded at night, indicating significance beyond the previously demonstrated role of maltose and starch breakdown in the initial phase of cold acclimation. Levels of some conventional cold induced metabolites, such as γ-aminobutyric acid, galactinol, raffinose and putrescine, exhibited diurnal and circadian oscillations and transcripts encoding their biosynthetic enzymes often also cycled and preceded their cold-induction, in agreement with transcriptional regulation. However, the accumulation of other cold-responsive metabolites, for instance homoserine, methionine and maltose, did not have consistent transcriptional regulation, implying that metabolic reconfiguration involves complex transcriptional and post-transcriptional mechanisms. These data demonstrate the importance of understanding cold acclimation in the correct day-night context, and are further

  2. Temperature acclimation of photosynthesis has only minor effects on gross primary productivity (GPP) in an Earth System Model (ESM)

    Science.gov (United States)

    Goll, Daniel; Brovkin, Victor; Kattge, Jens; Zaehle, Soenke; Reick, Christian

    2013-04-01

    are small, the model performance does not differ significantly between the different temperature photosynthesis formulation when compared to eddy covariance data. As Booth et al. (2012) did not account for acclimation but varied the short-term optimum temperature of photosynthesis they might have overestimated the importance of the optimum temperature. We conclude that long-term projections done with the MPI-ESM, as for example for the CMIP5 project, would not be strongly affected by the omission of acclimation, unlike suggested by Booth. Kattge, J. and Knorr, W. (2007),Temperature acclimation in a biochemical model of photosynthesis: a reanalysis of data from 36 species, Plant, Cell and Environment, 30, 1176-1190. Booth, B. B. B., Jones C. D., Collins, M., Totterdell, I. J., Cox, P. M., Sitch, S., Huntingford, C., Betts, R. A., Harris, G. R., Lloyd, J. (2012), High sensitivity of future global warming to land carbon cycle processes, Environmental Research Letters 7 (2), 024002.

  3. Thermal de-acclimation: how permanent are leaf phenotypes when cold-acclimated plants experience warming?

    Science.gov (United States)

    Gorsuch, Peter A; Pandey, Subedar; Atkin, Owen K

    2010-07-01

    We quantified a broad range of Arabidopsis thaliana (Col-0) leaf phenotypes for initially warm-grown (25/20 degrees C day/night) plants that were exposed to cold (5 degrees C) for periods of a few hours to 45 d before being transferred back to the warm, where leaves were allowed to mature. This allowed us to address the following questions: (1) For how long do warm-grown plants have to experience cold before developing leaves become irreversibly cold acclimated? (2) To what extent is the de-acclimation process associated with changes in leaf anatomy and physiology? We show that leaves that experience cold for extended periods during early development exhibit little plasticity in either photosynthesis or respiration, and they do not revert to a warm-associated carbohydrate profile. The eventual expansion rate in the warm was inversely related to the duration of previous cold treatment. Moreover, cold exposure of immature/developing leaves for as little as 5 d resulted in irreversible changes in the morphology of leaves that subsequently matured in the warm, with 15 d cold being sufficient for a permanent alteration of leaf anatomy. Collectively, these results highlight the impact of transitory cold during early leaf development in determining the eventual phenotype of leaves that mature in the warm.

  4. Short Duration Heat Acclimation in Australian Football Players

    Science.gov (United States)

    Kelly, Monica; Gastin, Paul B.; Dwyer, Daniel B; Sostaric, Simon; Snow, Rodney J.

    2016-01-01

    This study examined if five sessions of short duration (27 min), high intensity, interval training (HIIT) in the heat over a nine day period would induce heat acclimation in Australian football (AF) players. Fourteen professional AF players were matched for VO2peak (mL·kg-1·min-1) and randomly allocated into either a heat acclimation (Acc) (n = 7) or Control (Con) group (n = 7). The Acc completed five cycle ergometer HIIT sessions within a nine day period on a cycle ergometer in the heat (38.7 ± 0.5 °C; 34.4 ± 1.3 % RH), whereas Con trained in thermo-neutral conditions (22.3 ± 0.2 °C; 35.8 ± 0. % RH). Four days prior and two days post HIIT participants undertook a 30 min constant load cycling test at 60% V̇O2peak in the heat (37.9 ± 0.1 °C; 28.5 ± 0.7 % RH) during which VO2, blood lactate concentration ([Lac-]), heart rate (HR), rating of perceived exertion (RPE), thermal comfort, core and skin temperatures were measured. Heat acclimation resulted in reduced RPE, thermal comfort and [Lac-] (all p HIIT, in both groups. Heat acclimation did not influence any other measured variables. In conclusion, five short duration HIIT sessions in hot dry conditions induced limited heat acclimation responses in AF players during the in-season competition phase. In practice, the heat acclimation protocol can be implemented in a professional team environment; however the physiological adaptations resulting from such a protocol were limited. Key points Some minor heat acclimation adaptations can be induced in professional AF players with five 27 min non-consecutive, short duration HIIT sessions in the heat. The heat acclimation protocol employed in this study was able to be implemented in a professional team sport environment during an actual competitive season. Elevating and maintaining a high core temperature sufficient for heat acclimation likely requires a longer heat training session or some pre-heating prior to exercise. PMID:26957934

  5. Drinking and water balance during exercise and heat acclimation

    Science.gov (United States)

    Greenleaf, J. E.; Brock, P. J.; Keil, L. C.; Morse, J. T.

    1983-01-01

    The interactions between fluid intake and balance, and plasma ion, osmotic, and endocrine responses during dehydration produced by exercise in cool and warm environments during acclimation are explored. Two groups of five male subjects performed 8 days of ergometer exercise in hot and thermoneutral conditions, respectively. The exercise trials lasted 2 hr each. Monitoring was carried out on the PV, osmotic, sodium, and endocrine concentrations, voluntary fluid intake, fluid balances, and fluid deficits. A negative correlation was observed between the plasma sodium and osmolality during acclimation. The presence of hypervolemia during acclimation is suggested as a cause of drinking, while the vasopressin concentration was not found to be a significant factor stimulating drinking. Finally, the predominant mechanism in fluid intake during exercise and heat exposure is concluded to be the renin-angiotensin II system in the presence of reductions in total body water and extracellular plasma volumes.

  6. Short Duration Heat Acclimation in Australian Football Players

    Directory of Open Access Journals (Sweden)

    Monica Kelly, Paul B. Gastin, Daniel B Dwyer, Simon Sostaric, Rodney J. Snow

    2016-03-01

    Full Text Available This study examined if five sessions of short duration (27 min, high intensity, interval training (HIIT in the heat over a nine day period would induce heat acclimation in Australian football (AF players. Fourteen professional AF players were matched for VO2peak (mL·kg-1·min-1 and randomly allocated into either a heat acclimation (Acc (n = 7 or Control (Con group (n = 7. The Acc completed five cycle ergometer HIIT sessions within a nine day period on a cycle ergometer in the heat (38.7 ± 0.5 °C; 34.4 ± 1.3 % RH, whereas Con trained in thermo-neutral conditions (22.3 ± 0.2 °C; 35.8 ± 0. % RH. Four days prior and two days post HIIT participants undertook a 30 min constant load cycling test at 60% VO2peak in the heat (37.9 ± 0.1 °C; 28.5 ± 0.7 % RH during which VO2, blood lactate concentration ([Lac-], heart rate (HR, rating of perceived exertion (RPE, thermal comfort, core and skin temperatures were measured. Heat acclimation resulted in reduced RPE, thermal comfort and [Lac-] (all p < 0.05 during the submaximal exercise test in the heat. Heart rate was lower (p = 0.007 after HIIT, in both groups. Heat acclimation did not influence any other measured variables. In conclusion, five short duration HIIT sessions in hot dry conditions induced limited heat acclimation responses in AF players during the in-season competition phase. In practice, the heat acclimation protocol can be implemented in a professional team environment; however the physiological adaptations resulting from such a protocol were limited.

  7. Influence of ozone on cold acclimation in sugar maple seedlings

    Energy Technology Data Exchange (ETDEWEB)

    Bertrand, A. [Agriculture and Agri-Food Canada, Sainte-Foy, PQ (Canada) Research Station; Robitaille, G. [Natural Resources Canada, Ste. Foy, PQ (Canada) Canadian Forest Service; Nadeau, P.; Castonguay, Y. [Agriculture and Agri-Food Canada, Sainte-Foy, PQ (Canada) Research Station

    1999-07-01

    A study was carried out with the aim of determining: a) if exposure to ozone gas induces changes in the key parts of cold acclimation in maple seedlings; and b) if the putative changes effect the process of cold acclimation. Two year old seedlings were exposed to two concentrations of ozone, ambient ozone (low ozone), and threefold ambient ozone concentrations (high ozone) from June to September. During the fall, winter and spring, the seedlings were left outdoors to acclimate to natural winter conditions. The freezing tolerance of stems and root tissues was determined for high ozone and low ozone treated seedlings over the winter period. Concomitant determination of the concentrations of starch, sucrose, raffinose, and stachyose in the sugar maple roots as well as ABA concentration in the xylem sap were carried out to assess the molecular changes associated with the cold acclimation of seedlings in the two treatments. Exposure to high concentrations of ozone did not decrease the freezing tolerance of sugar maple roots and improved the freezing tolerance of the stems in the fall. During the period of cold acclimation, an eightfold increase in sucrose concentration occurred in roots and stems, while starch concentration decreased. In roots, the accumulation of soluble sugars coincided with the period of lowest soil temperature. This showed that temperature has a major influence on the amount of sugar formed and the degree of freezing tolerance. There were no ozone treatment effects on either starch hydrolysis or sucrose accumulation in roots. Sucrose is a membrane and protein stabilizer during winter drying. In roots, the concentrations of the galactose containing oligosaccharides, raffinose and stachyose, were higher in the high ozone treatment than in the low ozone treatment, and stachyose indicated a similar response in stems. There is a relation between the increase in ABA concentration and cold acclimation in the sugar maple. 29 refs., 7 figs.

  8. Unlocking the Constraints of Cyanobacterial Productivity: Acclimations Enabling Ultrafast Growth

    Energy Technology Data Exchange (ETDEWEB)

    Bernstein, Hans C.; McClure, Ryan S.; Hill, Eric A.; Markillie, Lye Meng; Chrisler, William B.; Romine, Margie F.; McDermott, Jason E.; Posewitz, Matthew C.; Bryant, Donald A.; Konopka, Allan E.; Fredrickson, James K.; Beliaev, Alexander S.

    2016-07-26

    ABSTRACT

    Harnessing the metabolic potential of photosynthetic microbes for next-generation biotechnology objectives requires detailed scientific understanding of the physiological constraints and regulatory controls affecting carbon partitioning between biomass, metabolite storage pools, and bioproduct synthesis. We dissected the cellular mechanisms underlying the remarkable physiological robustness of the euryhaline unicellular cyanobacteriumSynechococcussp. strain PCC 7002 (Synechococcus7002) and identify key mechanisms that allow cyanobacteria to achieve unprecedented photoautotrophic productivities (~2.5-h doubling time). Ultrafast growth ofSynechococcus7002 was supported by high rates of photosynthetic electron transfer and linked to significantly elevated transcription of precursor biosynthesis and protein translation machinery. Notably, no growth or photosynthesis inhibition signatures were observed under any of the tested experimental conditions. Finally, the ultrafast growth inSynechococcus7002 was also linked to a 300% expansion of average cell volume. We hypothesize that this cellular adaptation is required at high irradiances to support higher cell division rates and reduce deleterious effects, corresponding to high light, through increased carbon and reductant sequestration.

    IMPORTANCEEfficient coupling between photosynthesis and productivity is central to the development of biotechnology based on solar energy. Therefore, understanding the factors constraining maximum rates of carbon processing is necessary to identify regulatory mechanisms and devise strategies to overcome productivity constraints. Here, we interrogate the molecular mechanisms that operate at a systems level to allow cyanobacteria to achieve ultrafast growth. This was done by considering growth and photosynthetic kinetics with global transcription patterns. We have delineated

  9. Thermal acclimation of photosynthesis: on the importance of adjusting our definitions and accounting for thermal acclimation of respiration.

    Science.gov (United States)

    Way, Danielle A; Yamori, Wataru

    2014-02-01

    While interest in photosynthetic thermal acclimation has been stimulated by climate warming, comparing results across studies requires consistent terminology. We identify five types of photosynthetic adjustments in warming experiments: photosynthesis as measured at the high growth temperature, the growth temperature, and the thermal optimum; the photosynthetic thermal optimum; and leaf-level photosynthetic capacity. Adjustments of any one of these variables need not mean a concurrent adjustment in others, which may resolve apparently contradictory results in papers using different indicators of photosynthetic acclimation. We argue that photosynthetic thermal acclimation (i.e., that benefits a plant in its new growth environment) should include adjustments of both the photosynthetic thermal optimum (T opt) and photosynthetic rates at the growth temperature (A growth), a combination termed constructive adjustment. However, many species show reduced photosynthesis when grown at elevated temperatures, despite adjustment of some photosynthetic variables, a phenomenon we term detractive adjustment. An analysis of 70 studies on 103 species shows that adjustment of T opt and A growth are more common than adjustment of other photosynthetic variables, but only half of the data demonstrate constructive adjustment. No systematic differences in these patterns were found between different plant functional groups. We also discuss the importance of thermal acclimation of respiration for net photosynthesis measurements, as respiratory temperature acclimation can generate apparent acclimation of photosynthetic processes, even if photosynthesis is unaltered. We show that while dark respiration is often used to estimate light respiration, the ratio of light to dark respiration shifts in a non-predictable manner with a change in leaf temperature.

  10. The hidden function of photosynthesis: a sensing system for environmental conditions that regulates plant acclimation responses.

    Science.gov (United States)

    Pfannschmidt, Thomas; Yang, Chunhong

    2012-06-01

    Plants convert light energy from the sun into chemical energy by photosynthesis. Since they are sessile, they have to deal with a wide range of conditions in their immediate environment. Many abiotic and biotic parameters exhibit considerable fluctuations which can have detrimental effects especially on the efficiency of photosynthetic light harvesting. During evolution, plants, therefore, evolved a number of acclimation processes which help them to adapt photosynthesis to such environmental changes. This includes protective mechanisms such as excess energy dissipation and processes supporting energy redistribution, e.g. state transitions or photosystem stoichiometry adjustment. Intriguingly, all these responses are triggered by photosynthesis itself via the interplay of its light reaction and the Calvin-Benson cycle with the residing environmental condition. Thus, besides its primary function in harnessing and converting light energy, photosynthesis acts as a sensing system for environmental changes that controls molecular acclimation responses which adapt the photosynthetic function to the environmental change. Important signalling parameters directly or indirectly affected by the environment are the pH gradient across the thylakoid membrane and the redox states of components of the photosynthetic electron transport chain and/or electron end acceptors coupled to it. Recent advances demonstrate that these signals control post-translational modifications of the photosynthetic protein complexes and also affect plastid and nuclear gene expression machineries as well as metabolic pathways providing a regulatory framework for an integrated response of the plant to the environment at all cellular levels.

  11. Isopods failed to acclimate their thermal sensitivity of locomotor performance during predictable or stochastic cooling.

    Directory of Open Access Journals (Sweden)

    Matthew S Schuler

    Full Text Available Most organisms experience environments that vary continuously over time, yet researchers generally study phenotypic responses to abrupt and sustained changes in environmental conditions. Gradual environmental changes, whether predictable or stochastic, might affect organisms differently than do abrupt changes. To explore this possibility, we exposed terrestrial isopods (Porcellio scaber collected from a highly seasonal environment to four thermal treatments: (1 a constant 20°C; (2 a constant 10°C; (3 a steady decline from 20° to 10°C; and (4 a stochastic decline from 20° to 10°C that mimicked natural conditions during autumn. After 45 days, we measured thermal sensitivities of running speed and thermal tolerances (critical thermal maximum and chill-coma recovery time. Contrary to our expectation, thermal treatments did not affect the thermal sensitivity of locomotion; isopods from all treatments ran fastest at 33° to 34°C and achieved more than 80% of their maximal speed over a range of 10° to 11°C. Isopods exposed to a stochastic decline in temperature tolerated cold the best, and isopods exposed to a constant temperature of 20°C tolerated cold the worst. No significant variation in heat tolerance was observed among groups. Therefore, thermal sensitivity and heat tolerance failed to acclimate to any type of thermal change, whereas cold tolerance acclimated more during stochastic change than it did during abrupt change.

  12. High temperature acclimation of C4 photosynthesis is linked to changes in photosynthetic biochemistry.

    Science.gov (United States)

    Dwyer, Simon A; Ghannoum, Oula; Nicotra, Adrienne; von Caemmerer, Susanne

    2007-01-01

    With average global temperatures predicted to increase over the next century, it is important to understand the extent and mechanisms of C4 photosynthetic acclimation to modest increases in growth temperature. To this end, we compared the photosynthetic responses of two C4 grasses (Panicum coloratum and Cenchrus ciliaris) and one C4 dicot (Flaveria bidentis) to growth at moderate (25/20 degrees C, day/night) or high (35/30 degrees C, day/night) temperatures. In all three C4 species, CO2 assimilation rates (A) underwent significant thermal acclimation, such that when compared at growth temperatures, A increased less than what would be expected given the strong response of A to short-term changes in leaf temperature. Thermal photosynthetic acclimation was further manifested by an increase in the temperature optima of A, and a decrease in leaf nitrogen content and leaf mass per area in the high- relative to the moderate-temperature-grown plants. Reduced photosynthetic capacity at the higher growth temperature was underpinned by selective changes in photosynthetic components. Plants grown at the higher temperature had lower amounts of ribulose-1,5-bisphosphate carboxylase/oxygenase and cytochrome f and activity of carbonic anhydrase. The activities of photosystem II (PSII) and phosphoenolpyruvate carboxylase were not affected by growth temperature. Chlorophyll fluorescence measurements of F. bidentis showed a corresponding decrease in the quantum yield of PSII (phi(PSII)) and an increase in non-photochemical quenching (phi(NPQ)). It is concluded that through these biochemical changes, C4 plants maintain the balance between the various photosynthetic components at each growth temperature, despite the differing temperature dependence of each process. As such, at higher temperatures photosynthetic nitrogen use efficiency increases more than A. Our results suggest C4 plants will show only modest changes in photosynthetic rates in response to changes in growth temperature

  13. Enzymatic activity of rodents acclimated to cold and long scotophase

    Science.gov (United States)

    Fourie, F. Le R.; Haim, A.

    1980-09-01

    Rodents representative of a diurnal species ( Rhabdomys pumilio) as well as a nocturnal species ( Praomys natalensis) were acclimated to cold (Ta = 8°C) at a photoperiod of LD 12:12 and a long scotophase (LD 8; 16) at a temperature of 25° C(Ta). Control groups were kept for both species at Ta = 25° C and LD 12:12 and winter acclimated individuals were obtained during July and August to serve as further reference. Blood samples obtained from the tail were analysed for enzymes representative of three major biochemical pathways. The enzymatic activity of LDH (glycolytic pathway), MDH (Krebs cycle) and G6PDH (hexose monophosphate shunt, as an indicator of gonadal activity) were monitored to represent metabolic activity of the respective cycles. Cold acclimated as well as winter acclimatized mice revealed similar enzymatic patterns for both species and significant increases in LDH and MDH were recorded with a concurrent decrease in G6PDH activity. Specimens exposed to long scotophase exhibited similar enzymatic patterns for both species studied, but enzymatic activity was higher than those of cold acclimated individuals. From these results it is concluded that cold as well as long scotophase induce metabolic adaptations through biochemical activity in the experimental animals. The effect of long scotophase is assumed to be an important factor in the induction of winter acclimatization.

  14. Molecular processes of transgenerational acclimation to a warming ocean

    Science.gov (United States)

    Veilleux, Heather D.; Ryu, Taewoo; Donelson, Jennifer M.; van Herwerden, Lynne; Seridi, Loqmane; Ghosheh, Yanal; Berumen, Michael L.; Leggat, William; Ravasi, Timothy; Munday, Philip L.

    2015-12-01

    Some animals have the remarkable capacity to acclimate across generations to projected future climate change; however, the underlying molecular processes are unknown. We sequenced and assembled de novo transcriptomes of adult tropical reef fish exposed developmentally or transgenerationally to projected future ocean temperatures and correlated the resulting expression profiles with acclimated metabolic traits from the same fish. We identified 69 contigs representing 53 key genes involved in thermal acclimation of aerobic capacity. Metabolic genes were among the most upregulated transgenerationally, suggesting shifts in energy production for maintaining performance at elevated temperatures. Furthermore, immune- and stress-responsive genes were upregulated transgenerationally, indicating a new complement of genes allowing the second generation of fish to better cope with elevated temperatures. Other differentially expressed genes were involved with tissue development and transcriptional regulation. Overall, we found a similar suite of differentially expressed genes among developmental and transgenerational treatments. Heat-shock protein genes were surprisingly unresponsive, indicating that short-term heat-stress responses may not be a good indicator of long-term acclimation capacity. Our results are the first to reveal the molecular processes that may enable marine fishes to adjust to a future warmer environment over multiple generations.

  15. Molecular processes of transgenerational acclimation to a warming ocean

    KAUST Repository

    Veilleux, Heather D.

    2015-07-20

    Some animals have the remarkable capacity to acclimate across generations to projected future climate change1, 2, 3, 4; however, the underlying molecular processes are unknown. We sequenced and assembled de novo transcriptomes of adult tropical reef fish exposed developmentally or transgenerationally to projected future ocean temperatures and correlated the resulting expression profiles with acclimated metabolic traits from the same fish. We identified 69 contigs representing 53 key genes involved in thermal acclimation of aerobic capacity. Metabolic genes were among the most upregulated transgenerationally, suggesting shifts in energy production for maintaining performance at elevated temperatures. Furthermore, immune- and stress-responsive genes were upregulated transgenerationally, indicating a new complement of genes allowing the second generation of fish to better cope with elevated temperatures. Other differentially expressed genes were involved with tissue development and transcriptional regulation. Overall, we found a similar suite of differentially expressed genes among developmental and transgenerational treatments. Heat-shock protein genes were surprisingly unresponsive, indicating that short-term heat-stress responses may not be a good indicator of long-term acclimation capacity. Our results are the first to reveal the molecular processes that may enable marine fishes to adjust to a future warmer environment over multiple generations.

  16. Response of superoxide dismutase isoenzymes in tomato plants (Lycopersicon esculentum) during thermo-acclimation of the photosynthetic apparatus.

    Science.gov (United States)

    Camejo, Daymi; Martí, María del C; Nicolás, Emilio; Alarcón, Juan J; Jiménez, Ana; Sevilla, Francisca

    2007-11-01

    Seedlings of Lycopersicon esculentum Mill. var. Amalia were grown in a growth chamber under a photoperiod of 16 h light at 25 degrees C and 8 h dark at 20 degrees C. Five different treatments were applied to 30-day-old plants: Control treatment (plants maintained in the normal growth conditions throughout the experimental time), heat acclimation (plants exposed to 35 degrees C for 4 h in dark for 3 days), dark treatment (plants exposed to 25 degrees C for 4 h in dark for 3 days), heat acclimation plus heat shock (plants that previously received the heat acclimation treatment were exposed to 45 degrees C air temperature for 3 h in the light) and dark treatment plus heat shock (plants that previously received the dark treatment were exposed to 45 degrees C air temperature for 3 h in the light). Only the heat acclimation treatment increased the thermotolerance of the photosynthesis apparatus when the heat shock (45 degrees C) was imposed. In these plants, the CO(2) assimilation rate was not affected by heat shock and there was a slight and non-significant reduction in maximum carboxylation velocity of Rubisco (V(cmax)) and maximum electron transport rate contributing to Rubisco regeneration (J(max)). However, the plants exposed to dark treatment plus heat shock showed a significant reduction in the CO(2) assimilation rate and also in the values of V(cmax) and J(max). Chlorophyll fluorescence measurements showed increased thermotolerance in heat-acclimated plants. The values of maximum chlorophyll fluorescence (F(m)) were not modified by heat shock in these plants, while in the dark-treated plants that received the heat shock, the F(m) values were reduced, which provoked a significant reduction in the efficiency of photosystem II. A slight rise in the total superoxide dismutase (SOD) activity was found in the plants that had been subjected to both heat acclimation and heat shock, and this SOD activity was significantly higher than that found in the plants subjected to

  17. Diatom proteomics reveals unique acclimation strategies to mitigate Fe limitation.

    Directory of Open Access Journals (Sweden)

    Brook L Nunn

    Full Text Available Phytoplankton growth rates are limited by the supply of iron (Fe in approximately one third of the open ocean, with major implications for carbon dioxide sequestration and carbon (C biogeochemistry. To date, understanding how alteration of Fe supply changes phytoplankton physiology has focused on traditional metrics such as growth rate, elemental composition, and biophysical measurements such as photosynthetic competence (Fv/Fm. Researchers have subsequently employed transcriptomics to probe relationships between changes in Fe supply and phytoplankton physiology. Recently, studies have investigated longer-term (i.e. following acclimation responses of phytoplankton to various Fe conditions. In the present study, the coastal diatom, Thalassiosira pseudonana, was acclimated (10 generations to either low or high Fe conditions, i.e. Fe-limiting and Fe-replete. Quantitative proteomics and a newly developed proteomic profiling technique that identifies low abundance proteins were employed to examine the full complement of expressed proteins and consequently the metabolic pathways utilized by the diatom under the two Fe conditions. A total of 1850 proteins were confidently identified, nearly tripling previous identifications made from differential expression in diatoms. Given sufficient time to acclimate to Fe limitation, T. pseudonana up-regulates proteins involved in pathways associated with intracellular protein recycling, thereby decreasing dependence on extracellular nitrogen (N, C and Fe. The relative increase in the abundance of photorespiration and pentose phosphate pathway proteins reveal novel metabolic shifts, which create substrates that could support other well-established physiological responses, such as heavily silicified frustules observed for Fe-limited diatoms. Here, we discovered that proteins and hence pathways observed to be down-regulated in short-term Fe starvation studies are constitutively expressed when T. pseudonana is

  18. A cell-based model for the photoacclimation and CO(2)-acclimation of the photosynthetic apparatus.

    Science.gov (United States)

    Papadakis, I A; Kotzabasis, K; Lika, K

    2005-06-30

    We have developed a mathematical model based on the underlying mechanisms concerning the responses of the photosynthetic apparatus of a microalga cell which grows under constant incident light intensity and ambient CO(2) concentration. Photosynthesis involves light and carbon-fixation reactions which are mutually dependent and affect each other, but existing models for photosynthesis don't account for both reactions at once. Our modeling approach allows us to derive distinct equations for the rates of oxygen production, NADPH production, carbon dioxide fixation, carbohydrate production, and rejected energy, which are generally different. The production rates of the photosynthesis products are hyperbolic functions of light and CO(2) concentration. The model predicts that in the absence of photoinhibition, CO(2)-inhibition, photorespiration, and chlororespiration, a cell acclimated to high light and/or CO(2) concentration has higher photosynthetic capacity and lower photosynthetic efficiency than does a cell acclimated to low conditions. This results in crossing between the two curves which represent the oxygen production rates and carbon fixation rates in low and high conditions. Finally, in the absence of photoinhibition and CO(2)-inhibition, the model predicts the carbohydrate production rate in terms of both light intensity and CO(2) concentration.

  19. Integration of genome-scale modeling and transcript profiling reveals metabolic pathways underlying light and temperature acclimation in Arabidopsis.

    Science.gov (United States)

    Töpfer, Nadine; Caldana, Camila; Grimbs, Sergio; Willmitzer, Lothar; Fernie, Alisdair R; Nikoloski, Zoran

    2013-04-01

    Understanding metabolic acclimation of plants to challenging environmental conditions is essential for dissecting the role of metabolic pathways in growth and survival. As stresses involve simultaneous physiological alterations across all levels of cellular organization, a comprehensive characterization of the role of metabolic pathways in acclimation necessitates integration of genome-scale models with high-throughput data. Here, we present an integrative optimization-based approach, which, by coupling a plant metabolic network model and transcriptomics data, can predict the metabolic pathways affected in a single, carefully controlled experiment. Moreover, we propose three optimization-based indices that characterize different aspects of metabolic pathway behavior in the context of the entire metabolic network. We demonstrate that the proposed approach and indices facilitate quantitative comparisons and characterization of the plant metabolic response under eight different light and/or temperature conditions. The predictions of the metabolic functions involved in metabolic acclimation of Arabidopsis thaliana to the changing conditions are in line with experimental evidence and result in a hypothesis about the role of homocysteine-to-Cys interconversion and Asn biosynthesis. The approach can also be used to reveal the role of particular metabolic pathways in other scenarios, while taking into consideration the entirety of characterized plant metabolism.

  20. Single-cell C(4) photosynthesis: efficiency and acclimation of Bienertia sinuspersici to growth under low light.

    Science.gov (United States)

    Stutz, Samantha S; Edwards, Gerald E; Cousins, Asaph B

    2014-04-01

    Traditionally, it was believed that C(4) photosynthesis required two types of chlorenchyma cells to concentrate CO(2) within the leaf. However, several species have been identified that perform C(4) photosynthesis using dimorphic chloroplasts within an individual cell. The goal of this research was to determine how growth under limited light affects leaf structure, biochemistry and efficiency of the single-cell CO(2) -concentrating mechanism in Bienertia sinuspersici. Measurements of rates of CO(2) assimilation and CO(2) isotope exchange in response to light intensity and O(2) were used to determine the efficiency of the CO(2) -concentrating mechanism in plants grown under moderate and low light. In addition, enzyme assays, chlorophyll content and light microscopy of leaves were used to characterize acclimation to light-limited growth conditions. There was acclimation to growth under low light with a decrease in capacity for photosynthesis when exposed to high light. This was associated with a decreased investment in biochemistry for carbon assimilation with only subtle changes in leaf structure and anatomy. The capture and assimilation of CO(2) delivered by the C(4) cycle was lower in low-light-grown plants. Low-light-grown plants were able to acclimate to maintain structural and functional features for the performance of efficient single-cell C(4) photosynthesis.

  1. Above-Ground Dimensions and Acclimation Explain Variation in Drought Mortality of Scots Pine Seedlings from Various Provenances.

    Science.gov (United States)

    Seidel, Hannes; Menzel, Annette

    2016-01-01

    Seedling establishment is a critical part of the life cycle, thus seedling survival might be even more important for forest persistence under recent and future climate change. Scots pine forests have been disproportionally more affected by climate change triggered forest-dieback. Nevertheless, some Scots pine provenances might prove resilient to future drought events because of the species' large distributional range, genetic diversity, and adaptation potential. However, there is a lack of knowledge on provenance-specific survival under severe drought events and on how acclimation alters survival rates in Scots pine seedlings. We therefore conducted two drought-induced mortality experiments with potted Scots pine seedlings in a greenhouse. In the first experiment, 760 three-year-old seedlings from 12 different provenances of the south-western distribution range were subjected to the same treatment followed by the mortality experiment in 2014. In the second experiment, we addressed the question of whether acclimation to re-occurring drought stress events and to elevated temperature might decrease mortality rates. Thus, 139 four-year-old seedlings from France, Germany, and Poland were subjected to different temperature regimes (2012-2014) and drought treatments (2013-2014) before the mortality experiment in 2015. Provenances clearly differed in their hazard of drought-induced mortality, which was only partly related to the climate of their origin. Drought acclimation decreased the hazard of drought-induced mortality. Above-ground dry weight and height were the main determinants for the hazard of mortality, i.e., heavier and taller seedlings were more prone to mortality. Consequently, Scots pine seedlings exhibit a considerable provenance-specific acclimation potential against drought mortality and the selection of suitable provenances might thus facilitate seedling establishment and the persistence of Scots pine forest.

  2. Acclimation increases freezing stress response of Arabidopsis thaliana at proteome level

    KAUST Repository

    Fanucchi, Francesca

    2012-06-01

    This study used 2DE to investigate how Arabidopsis thaliana modulates protein levels in response to freezing stress after sub-lethal exposure at - 10 °C, both in cold-acclimated and in non-acclimated plants. A map was implemented in which 62 spots, corresponding to 44 proteins, were identified. Twenty-two spots were modulated upon treatments, and the corresponding proteins proved to be related to photosynthesis, energy metabolism, and stress response. Proteins demonstrated differences between control and acclimation conditions. Most of the acclimation-responsive proteins were either not further modulated or they were down-modulated by freezing treatment, indicating that the levels reached during acclimation were sufficient to deal with freezing. Anabolic metabolism appeared to be down-regulated in favor of catabolic metabolism. Acclimated plants and plants submitted to freezing after acclimation showed greater reciprocal similarity in protein profiles than either showed when compared both to control plants and to plants frozen without acclimation. The response of non-acclimated plants was aimed at re-modulating photosynthetic apparatus activity, and at increasing the levels of proteins with antioxidant-, molecular chaperone-, or post-transcriptional regulative functions. These changes, even less effective than the acclimation strategy, might allow the injured plastids to minimize the production of non-useful metabolites and might counteract photosynthetic apparatus injuries. © 2012 Elsevier B.V. All rights reserved.

  3. Acclimation of microalgae to wastewater environments involves increased oxidative stress tolerance activity.

    Science.gov (United States)

    Osundeko, Olumayowa; Dean, Andrew P; Davies, Helena; Pittman, Jon K

    2014-10-01

    A wastewater environment can be particularly toxic to eukaryotic microalgae. Microalgae can adapt to these conditions but the specific mechanisms that allow strains to tolerate wastewater environments are unclear. Furthermore, it is unknown whether the ability to acclimate microalgae to tolerate wastewater is an innate or species-specific characteristic. Six different species of microalgae (Chlamydomonas debaryana, Chlorella luteoviridis, Chlorella vulgaris, Desmodesmus intermedius, Hindakia tetrachotoma and Parachlorella kessleri) that had never previously been exposed to wastewater conditions were acclimated over an 8-week period in secondary-treated municipal wastewater. With the exception of C. debaryana, acclimation to wastewater resulted in significantly higher growth rate and biomass productivity. With the exception of C. vulgaris, total chlorophyll content was significantly increased in all acclimated strains, while all acclimated strains showed significantly increased photosynthetic activity. The ability of strains to acclimate was species-specific, with two species, C. luteoviridis and P. kessleri, able to acclimate more efficiently to the stress than C. debaryana and D. intermedius. Metabolic fingerprinting of the acclimated and non-acclimated microalgae using Fourier transform infrared spectroscopy was able to differentiate strains on the basis of metabolic responses to the stress. In particular, strains exhibiting greater stress response and altered accumulation of lipids and carbohydrates could be distinguished. The acclimation to wastewater tolerance was correlated with higher accumulation of carotenoid pigments and increased ascorbate peroxidase activity.

  4. Cold acclimation induced genes of trifoliate orange (Poncirus trifoliata).

    Science.gov (United States)

    Zhang, Can-kui; Lang, Ping; Dane, Fenny; Ebel, Robert C; Singh, Narendra K; Locy, Robert D; Dozier, William A

    2005-03-01

    Commercial citrus varieties are sensitive to low temperature. Poncirus trifoliata is a close relative of Citrus species and has been widely used as a cold-hardy rootstock for citrus production in low-temperature environments. mRNA differential display-reverse transcription (DDRT)-PCR and quantitative relative-RT-PCR were used to study gene expression of P. trifoliata under a gradual cold-acclimation temperature regime. Eight up-regulated cDNA fragments were isolated and sequenced. These fragments showed high similarities at the amino acid level to the following genes with known functions: betaine/proline transporter, water channel protein, aldo-keto reductase, early light-induced protein, nitrate transporter, tetratricopeptide-repeat protein, F-box protein, and ribosomal protein L15. These cold-acclimation up-regulated genes in P. trifoliata are also regulated by osmotic and photo-oxidative signals in other plants.

  5. The Transcriptional Responses and Metabolic Consequences of Acclimation to Elevated Light Exposure in Grapevine Berries

    Directory of Open Access Journals (Sweden)

    Kari du Plessis

    2017-07-01

    Full Text Available An increasing number of field studies that focus on grapevine berry development and ripening implement systems biology approaches; the results are highlighting not only the intricacies of the developmental programming/reprogramming that occurs, but also the complexity of how profoundly the microclimate influences the metabolism of the berry throughout the different stages of development. In a previous study we confirmed that a leaf removal treatment to Sauvignon Blanc grapes, grown in a highly characterized vineyard, primarily affected the level of light exposure to the berries throughout their development. A full transcriptomic analysis of berries from this model vineyard details the underlying molecular responses of the berries in reaction to the exposure and show how the berries acclimated to the imposing light stress. Gene expression involved in the protection of the photosynthetic machinery through rapid protein-turnover and the expression of photoprotective flavonoid compounds were most significantly affected in green berries. Overall, the transcriptome analysis showed that the berries implemented multiple stress-mitigation strategies in parallel and metabolite analysis was used to support the main findings. Combining the transcriptome data and amino acid profiling provided evidence that amino acid catabolism probably contributed to the mitigation of a likely energetic deficit created by the upregulation of (energetically costly stress defense mechanisms. Furthermore, the rapid turnover of essential proteins involved in the maintenance of primary metabolism and growth in the photosynthetically active grapes appeared to provide precursors for the production of protective secondary metabolites such as apocarotenoids and flavonols in the ripening stages of the berries. Taken together, these results confirmed that the green grape berries responded to light stress much like other vegetative organs and were able to acclimate to the increased

  6. No Inbreeding depression for low temperature developmental acclimation across multiple drosophila species

    DEFF Research Database (Denmark)

    Kristensen, Torsten Nygård; Loeschcke, Volker; Bilde, Trine

    2011-01-01

    is highly species specific, and differs among ecotypes (e.g., tropical and widespread species). Apart from being exposed to thermal stress many small and fragmented populations face genetic challenges due to, for example, inbreeding. Inbreeding has been shown to reduce inherent resistance levels toward......Populations are from time to time exposed to stressful temperatures. Their thermal resistance levels are determined by inherent and plastic mechanisms, which are both likely to be under selection in natural populations. Previous studies on Drosophila species have shown that inherent resistance...... stressful temperatures, but whether adaptation to thermal stress through plastic responses also is affected by inbreeding is so far not clear. In this study, we test inherent cold resistance and the ability to respond plastically to temperature changes through developmental cold acclimation in inbred...

  7. Costs and benefits of cold acclimation in field released Drosophila

    DEFF Research Database (Denmark)

    Kristensen, Torsten N; Hoffmann, Ary A; Overgaard, Johannes

    2008-01-01

    One way animals can counter the effects of climatic extremes is via physiological acclimation, but acclimating to one extreme might decrease performance under different conditions. Here, we use field releases of Drosophila melanogaster on two continents across a range of temperatures to test...... acclimation that standard laboratory assays do not detect. Thus, although physiological acclimation may dramatically improve fitness over a narrow set of thermal conditions, it may have the opposite effect once conditions extend outside this range, an increasingly likely scenario as temperature variability...

  8. Reproductive acclimation to increased water temperature in a tropical reef fish.

    Science.gov (United States)

    Donelson, Jennifer M; McCormick, Mark I; Booth, David J; Munday, Philip L

    2014-01-01

    Understanding the capacity of organisms to cope with projected global warming through acclimation and adaptation is critical to predicting their likely future persistence. While recent research has shown that developmental acclimation of metabolic attributes to ocean warming is possible, our understanding of the plasticity of key fitness-associated traits, such as reproductive performance, is lacking. We show that while the reproductive ability of a tropical reef fish is highly sensitive to increases in water temperature, reproductive capacity at +1.5°C above present-day was improved to match fish maintained at present-day temperatures when fish complete their development at the higher temperature. However, reproductive acclimation was not observed in fish reared at +3.0°C warmer than present-day, suggesting limitations to the acclimation possible within one generation. Surprisingly, the improvements seen in reproduction were not predicted by the oxygen- and capacity-limited thermal tolerance hypothesis. Specifically, pairs reared at +1.5°C, which showed the greatest capacity for reproductive acclimation, exhibited no acclimation of metabolic attributes. Conversely, pairs reared at +3.0°C, which exhibited acclimation in resting metabolic rate, demonstrated little capacity for reproductive acclimation. Our study suggests that understanding the acclimation capacity of reproductive performance will be critically important to predicting the impacts of climate change on biological systems.

  9. Rapid transcriptional acclimation following transgenerational exposure of oysters to ocean acidification.

    Science.gov (United States)

    Goncalves, Priscila; Anderson, Kelli; Thompson, Emma L; Melwani, Aroon; Parker, Laura M; Ross, Pauline M; Raftos, David A

    2016-10-01

    Marine organisms need to adapt in order to cope with the adverse effects of ocean acidification and warming. Transgenerational exposure to CO2 stress has been shown to enhance resilience to ocean acidification in offspring from a number of species. However, the molecular basis underlying such adaptive responses is currently unknown. Here, we compared the transcriptional profiles of two genetically distinct oyster breeding lines following transgenerational exposure to elevated CO2 in order to explore the molecular basis of acclimation or adaptation to ocean acidification in these organisms. The expression of key target genes associated with antioxidant defence, metabolism and the cytoskeleton was assessed in oysters exposed to elevated CO2 over three consecutive generations. This set of target genes was chosen specifically to test whether altered responsiveness of intracellular stress mechanisms contributes to the differential acclimation of oyster populations to climate stressors. Transgenerational exposure to elevated CO2 resulted in changes to both basal and inducible expression of those key target genes (e.g. ecSOD, catalase and peroxiredoxin 6), particularly in oysters derived from the disease-resistant, fast-growing B2 line. Exposure to CO2 stress over consecutive generations produced opposite and less evident effects on transcription in a second population that was derived from wild-type (nonselected) oysters. The analysis of key target genes revealed that the acute responses of oysters to CO2 stress appear to be affected by population-specific genetic and/or phenotypic traits and by the CO2 conditions to which their parents had been exposed. This supports the contention that the capacity for heritable change in response to ocean acidification varies between oyster breeding lines and is mediated by parental conditioning. © 2016 John Wiley & Sons Ltd.

  10. Cold resistance depends on acclimation and behavioral caste in a temperate ant

    Science.gov (United States)

    Modlmeier, Andreas P.; Pamminger, Tobias; Foitzik, Susanne; Scharf, Inon

    2012-10-01

    Adjusting to low temperatures is important for animals living in cold environments. We studied the chill-coma recovery time in temperate ant workers ( Temnothorax nylanderi) from colonies collected in autumn and spring in Germany. We experimentally acclimated these ant colonies to cold temperatures followed by warm temperatures. As expected, cold-acclimated workers recovered faster from freezing temperatures, but subsequent heat acclimation did not change the short recovery times observed after cold acclimation. Hence, either heat acclimation improves cold tolerance, possibly as a general response to stress, or at least it does not negate enhanced cold tolerance following cold acclimation. Colonies collected in spring showed similar cold tolerance levels to cold-acclimated colonies in the laboratory. Next, we compared the chill-coma recovery time of different worker castes and found that exterior workers recovered faster than interior workers. This difference may be related to their more frequent exposure to cold, higher activity level, or distinct physiology. Interior workers were also heavier and showed a higher gaster-to-head ratio and thorax ratio compared to exterior workers. An obvious difference between exterior and interior workers is activity level, but we found no link between activity and cold tolerance. This suggests that physiology rather than behavioral differences could cause the increased cold tolerance of exterior workers. Our study reveals the importance of acclimation for cold tolerance under natural and standardized conditions and demonstrates differences in cold tolerance and body dimensions in monomorphic behavioral castes of an ant.

  11. The impact of anode acclimation strategy on microbial electrolysis cell treating hydrogen fermentation effluent

    DEFF Research Database (Denmark)

    Li, Xiaohu; Zhang, Ruizhe; Qian, Yawei

    2017-01-01

    The impact of different anode acclimation methods for enhancing hydrogen production in microbial electrolysis cell (MEC) was investigated in this study. The anodes were first acclimated in microbial fuel cells using acetate, butyrate and corn stalk fermentation effluent (CSFE) as substrate before...

  12. Low salinity acclimation and thyroid hormone metabolizing enzymes in gilthead seabream (Sparus auratus)

    NARCIS (Netherlands)

    Klaren, P.H.M.; Guzman, J.M.; Reutelingsperger, S.J.; Mancera, J.M.; Flik, G.

    2007-01-01

    We investigated the effect of acclimation to low salinity water of gilthead seabream (Sparus auratus), a euryhaline seawater teleost, on the activities of thyroid hormone-metabolizing enzymes in gills, kidney, and liver. Following acclimation to low salinity water, the plasma free thyroxine (T(4))

  13. Low salinity acclimation and thyroid hormone metabolizing enzymes in gilthead seabream (Sparus auratus)

    NARCIS (Netherlands)

    Klaren, P.H.M.; Guzman, J.M.; Reutelingsperger, S.J.; Mancera, J.M.; Flik, G.

    2007-01-01

    We investigated the effect of acclimation to low salinity water of gilthead seabream (Sparus auratus), a euryhaline seawater teleost, on the activities of thyroid hormone-metabolizing enzymes in gills, kidney, and liver. Following acclimation to low salinity water, the plasma free thyroxine (T(4)) c

  14. Heat and cold acclimation in helium-cold hypothermia in the hamster.

    Science.gov (United States)

    Musacchia, X. J.

    1972-01-01

    A study was made of the effects of acclimation of hamsters to high (34-35 C) and low (4-5 C) temperatures for periods up to 6 weeks on the induction of hypothermia in hamsters. Hypothermia was achieved by exposing hamsters to a helox mixture of 80% helium and 20% oxygen at 0 C. Hypothermic induction was most rapid (2-3 hr) in heat-acclimated hamsters and slowest (6-12 hr) in cold-acclimated hamsters. The induction period was intermediate (5-8 hr) in room temperature nonacclimated animals (controls). Survival time in hypothermia was relatable to previous temperature acclimations. The hypothesis that thermogenesis in cold-acclimated hamsters would accentuate resistance to induction of hypothermia was substantiated.

  15. Role of Leptin in Metabolic Adaptation During Cold Acclimation

    Directory of Open Access Journals (Sweden)

    Gang-Bin Tang

    2013-11-01

    Full Text Available Chronic cold exposure stimulates thermogenesis in brown adipose tissue, resulting in fat mobilization and compensatory hyperphagia. Mostly, these physiological events are accompanied by a remarkable reduction in serum leptin levels. However, the physiological roles of hypoleptinemia in cold adaptation are still not fully clear. We hypothesized that leptin is the keystone of the regulatory systems linking energy balance to cold adaptation. Leptin treatment (5μg/day decreased food intake, body weight, serum ghrelin levels and hypothalamic melanin-concentrating hormone (MCH gene expression. Food restriction in the pair-fed group mimicked most of the effects induced by leptin treatment. Central coadministration of ghrelin (1.2 μg/day partially reversed the effect of leptin on hypothalamic MCH mRNA, but it did not block the reducing effects of leptin on food intake, body weight and serum ghrelin levels. In addition, hypothalamic pro-opiomelanocortin gene expression increased significantly in response to the coadministration of leptin and ghrelin. Collectively, we conclude that the regulatory effects of leptin on energy balance in cold-acclimated rats are dependent on feeding, which may involve the reduction of hypothalamic MCH gene expression. We found no evidence for ghrelin involvement in the regulation of leptin on food intake and body weight during cold acclimation.

  16. Low-temperature acclimation of barley cultivars used as parents in mapping populations: response to photoperiod, vernalization and phenological development.

    Science.gov (United States)

    Limin, Allen; Corey, Ann; Hayes, Patrick; Fowler, D Brian

    2007-06-01

    Six barley (Hordeum vulgare L.) accessions, previously used as parents of mapping populations, were evaluated for characters potentially affecting the location of low-temperature (LT) tolerance QTLs. Three were of winter growth habit (Kompolti Korai, Nure, and Strider), one was facultative (Dicktoo) and two were spring (Morex and Tremois). Final leaf number (FLN) and LT(50 )were determined at weekly intervals from 0 to 98 days of LT acclimation/vernalization under both long day (LD) and short day (SD) photoperiods. The point of vegetative/reproductive transition was determined from measurements of double ridge (DR) formation and FLN. With the exception of Nure, SD delayed development by increasing leaf production. Dicktoo was extremely SD sensitive lengthening its vegetative phase by more than 63 days relative to the LD photoperiod. SD had the opposite effect on Nure, causing an accelerating of flowering exhibiting the characteristic of 'short day vernalization'. All accessions except Dicktoo and Kompolti Korai acclimated rapidly in the first 7 days of LT exposure, approaching their maximum LT tolerance in 14-21 days. Dicktoo and Kompolti Korai continued to slowly acclimate until reproductive transition. The results emphasize two important points: (1) the location of QTLs for LT tolerance, and as a consequence the identification of putative candidate genes, will be a function of the genotypes sampled, the experimental conditions used, and the quality of the phenotypic data and (2) the barley LT tolerance pathway reaches an early impediment relative to closely related more hardy members of the Triticeae such as wheat and rye.

  17. Carbon fluxes acclimate more strongly to elevated growth temperatures than to elevated CO2 concentrations in a northern conifer.

    Science.gov (United States)

    Kroner, Yulia; Way, Danielle A

    2016-08-01

    Increasing temperatures and atmospheric CO2 concentrations will affect tree carbon fluxes, generating potential feedbacks between forests and the global climate system. We studied how elevated temperatures and CO2 impacted leaf carbon dynamics in Norway spruce (Picea abies), a dominant northern forest species, to improve predictions of future photosynthetic and respiratory fluxes from high-latitude conifers. Seedlings were grown under ambient (AC, c. 435 μmol mol(-1) ) or elevated (EC, 750 μmol mol(-1) ) CO2 concentrations at ambient, +4 °C, or +8 °C growing temperatures. Photosynthetic rates (Asat ) were high in +4 °C/EC seedlings and lowest in +8 °C spruce, implying that moderate, but not extreme, climate change may stimulate carbon uptake. Asat , dark respiration (Rdark ), and light respiration (Rlight ) rates acclimated to temperature, but not CO2 : the thermal optimum of Asat increased, and Rdark and Rlight were suppressed under warming. In all treatments, the Q10 of Rlight (the relative increase in respiration for a 10 °C increase in leaf temperature) was 35% higher than the Q10 of Rdark , so the ratio of Rlight to Rdark increased with rising leaf temperature. However, across all treatments and a range of 10-40 °C leaf temperatures, a consistent relationship between Rlight and Rdark was found, which could be used to model Rlight in future climates. Acclimation reduced daily modeled respiratory losses from warm-grown seedlings by 22-56%. When Rlight was modeled as a constant fraction of Rdark , modeled daily respiratory losses were 11-65% greater than when using measured values of Rlight . Our findings highlight the impact of acclimation to future climates on predictions of carbon uptake and losses in northern trees, in particular the need to model daytime respiratory losses from direct measurements of Rlight or appropriate relationships with Rdark .

  18. Responses and acclimation of Chinese cork oak (Quercus variabilis Bl.) to metal stress: the inducible antimony tolerance in oak trees.

    Science.gov (United States)

    Zhao, Xiulian; Zheng, Lingyu; Xia, Xinli; Yin, Weilun; Lei, Jingpin; Shi, Shengqing; Shi, Xiang; Li, Huiqing; Li, Qinghe; Wei, Yuan; Chang, Ermei; Jiang, Zeping; Liu, Jianfeng

    2015-08-01

    Antimony (Sb) pollution has become a pressing environmental problem in recent years. Trees have been proven to have great potential for the feasible phytomanagement; however, little is known about Sb retention and tolerance in trees. The Chinese cork oak (Quercus variabilis Bl.) is known to be capable of growth in soils containing high concentrations of Sb. This study explored in detail the retention and acclimation of Q. variabilis under moderate and high external Sb levels. Results revealed that Q. variabilis could tolerate and accumulate high Sb (1623.39 mg kg(-1) DW) in roots. Dynamics of Sb retention in leaves, stems, and roots of Q. variabilis were different. Leaf Sb remained at a certain level for several weeks, while in roots and stems, Sb concentrations continued to increase. Sb damaged tree's PSII reaction cores but elicited defense mechanism at the donor side of PSII. It affected the electron transport flow after QA (-) more strongly than the oxygen-evolving complex and light-harvesting pigment-protein complex II. Sb also decreased leaf chlorophyll concentrations and therefore inhibited plant growth. During acclimation to Sb toxicity, Sb concentrations in leaves, stems, and roots decreased, with photosynthetic activity and pigments recovering to normal levels by the end of the experiment. These findings suggest that Sb tolerance in Q. variabilis is inducible. Acclimation seems to be related to homeostasis of Sb in plants. Results of this study can provide useful information for trees breeding and selection of Sb phytomanagement strategies, exploiting the established ability of Q. variabilis to transport, delocalize in the leaves, and tolerate Sb pollutions.

  19. Trait Acclimation Mitigates Mortality Risks of Tropical Canopy Trees under Global Warming.

    Science.gov (United States)

    Sterck, Frank; Anten, Niels P R; Schieving, Feike; Zuidema, Pieter A

    2016-01-01

    There is a heated debate about the effect of global change on tropical forests. Many scientists predict large-scale tree mortality while others point to mitigating roles of CO2 fertilization and - the notoriously unknown - physiological trait acclimation of trees. In this opinion article we provided a first quantification of the potential of trait acclimation to mitigate the negative effects of warming on tropical canopy tree growth and survival. We applied a physiological tree growth model that incorporates trait acclimation through an optimization approach. Our model estimated the maximum effect of acclimation when trees optimize traits that are strongly plastic on a week to annual time scale (leaf photosynthetic capacity, total leaf area, stem sapwood area) to maximize carbon gain. We simulated tree carbon gain for temperatures (25-35°C) and ambient CO2 concentrations (390-800 ppm) predicted for the 21st century. Full trait acclimation increased simulated carbon gain by up to 10-20% and the maximum tolerated temperature by up to 2°C, thus reducing risks of tree death under predicted warming. Functional trait acclimation may thus increase the resilience of tropical trees to warming, but cannot prevent tree death during extremely hot and dry years at current CO2 levels. We call for incorporating trait acclimation in field and experimental studies of plant functional traits, and in models that predict responses of tropical forests to climate change.

  20. Trait acclimation mitigates mortality risks of tropical canopy trees under global warming

    Directory of Open Access Journals (Sweden)

    Frank eSterck

    2016-05-01

    Full Text Available There is a heated debate about the effect of global change on tropical forests. Many scientists predict large-scale tree mortality while others point to mitigating roles of CO2 fertilization and – the notoriously unknown – physiological trait acclimation of trees. In this opinion article we provided a first quantification of the potential of trait acclimation to mitigate the negative effects of warming on tropical canopy tree growth and survival. We applied a physiological tree growth model that incorporates trait acclimation through an optimization approach. Our model estimated the maximum effect of acclimation when trees optimize traits that are strongly plastic on a week to annual time scale (leaf photosynthetic capacity, total leaf area, stem sapwood area to maximize carbon gain. We simulated tree carbon gain for temperatures (25-35ºC and ambient CO2 concentrations (390-800 ppm predicted for the 21st century. Full trait acclimation increased simulated carbon gain by up to 10-20% and the maximum tolerated temperature by up to 2ºC, thus reducing risks of tree death under predicted warming. Functional trait acclimation may thus increase the resilience of tropical trees to warming, but cannot prevent tree death during extremely hot and dry years at current CO2 levels. We call for incorporating trait acclimation in field and experimental studies of plant functional traits, and in models that predict responses of tropical forests to climate change.

  1. Global convergence in leaf respiration from estimates of thermal acclimation across time and space.

    Science.gov (United States)

    Vanderwel, Mark C; Slot, Martijn; Lichstein, Jeremy W; Reich, Peter B; Kattge, Jens; Atkin, Owen K; Bloomfield, Keith J; Tjoelker, Mark G; Kitajima, Kaoru

    2015-09-01

    Recent compilations of experimental and observational data have documented global temperature-dependent patterns of variation in leaf dark respiration (R), but it remains unclear whether local adjustments in respiration over time (through thermal acclimation) are consistent with the patterns in R found across geographical temperature gradients. We integrated results from two global empirical syntheses into a simple temperature-dependent respiration framework to compare the measured effects of respiration acclimation-over-time and variation-across-space to one another, and to a null model in which acclimation is ignored. Using these models, we projected the influence of thermal acclimation on: seasonal variation in R; spatial variation in mean annual R across a global temperature gradient; and future increases in R under climate change. The measured strength of acclimation-over-time produces differences in annual R across spatial temperature gradients that agree well with global variation-across-space. Our models further project that acclimation effects could potentially halve increases in R (compared with the null model) as the climate warms over the 21st Century. Convergence in global temperature-dependent patterns of R indicates that physiological adjustments arising from thermal acclimation are capable of explaining observed variation in leaf respiration at ambient growth temperatures across the globe. © 2015 The Authors. New Phytologist © 2015 New Phytologist Trust.

  2. Thermal sensitivity does not determine acclimation capacity for a tropical reef fish.

    Science.gov (United States)

    Donelson, Jennifer M; Munday, Philip L

    2012-09-01

    1. Short-term measures of metabolic responses to warmer environments are expected to indicate the sensitivity of species to regional warming. However, given time, species may be able to acclimate to increasing temperature. Thus, it is useful to determine if short-term responses provide a good predictor for long-term acclimation ability. 2. The tropical reef fish Acanthochromis polyacanthus was used to test whether the ability for developmental thermal acclimation of two populations was indicated by their short-term metabolic response to temperature. 3. While both populations exhibited similar short-term responses of resting metabolic rate (RMR) to temperature, fish from the higher-latitude population were able to fully acclimate RMR, while the lower-latitude population could only partially compensate RMR at the warmest temperature. These differences in acclimation ability are most likely due to genetic differences between the populations rather than differences in thermal regimes. 4. This research indicates that acclimation ability may vary greatly between populations and that understanding such variation will be critical for predicting the impacts of warming environmental temperatures. Moreover, the thermal metabolic reaction norm does not appear to be a good predictor of long-term acclimation ability.

  3. The effects of acclimation and rates of temperature change on critical thermal limits in Tenebrio molitor (Tenebrionidae) and Cyrtobagous salviniae (Curculionidae).

    Science.gov (United States)

    Allen, Jessica L; Clusella-Trullas, Susana; Chown, Steven L

    2012-05-01

    Critical thermal limits provide an indication of the range of temperatures across which organisms may survive, and the extent of the lability of these limits offers insights into the likely impacts of changing thermal environments on such survival. However, investigations of these limits may be affected by the circumstances under which trials are undertaken. Only a few studies have examined these effects, and typically not for beetles. This group has also not been considered in the context of the time courses of acclimation and its reversal, both of which are important for estimating the responses of species to transient temperature changes. Here we therefore examine the effects of rate of temperature change on critical thermal maxima (CT(max)) and minima (CT(min)), as well as the time course of the acclimation response and its reversal in two beetle species, Tenebrio molitor and Cyrtobagous salviniae. Increasing rates of temperature change had opposite effects on T. molitor and C. salviniae. In T. molitor, faster rates of change reduced both CT(max) (c. 2°C) and CT(min) (c. 3°C), while in C. salviniae faster rates of change increased both CT(max) (c. 6°C) and CT(min) (c. 4°C). CT(max) in T. molitor showed little response to acclimation, while the response to acclimation of CT(min) was most pronounced following exposure to 35°C (from 25°C) and was complete within 24 h. The time course of acclimation of CT(max) in C. salviniae was 2 days when exposed to 36°C (from c. 26°C), while that of CT(min) was less than 3 days when exposed to 18°C. In T. molitor, the time course of reacclimation to 25°C after treatments at 15°C and 35°C at 75% RH was longer than the time course of acclimation, and varied from 3-6 days for CT(max) and 6 days for CT(min). In C. salviniae, little change in CT(max) and CT(min) (molitor and C. salviniae may be restricted in their ability to respond to transient temperature changes at short-time scales, and instead may have to rely on

  4. An integrated analysis of molecular acclimation to high light in the marine diatom Phaeodactylum tricornutum.

    Directory of Open Access Journals (Sweden)

    Marianne Nymark

    Full Text Available Photosynthetic diatoms are exposed to rapid and unpredictable changes in irradiance and spectral quality, and must be able to acclimate their light harvesting systems to varying light conditions. Molecular mechanisms behind light acclimation in diatoms are largely unknown. We set out to investigate the mechanisms of high light acclimation in Phaeodactylum tricornutum using an integrated approach involving global transcriptional profiling, metabolite profiling and variable fluorescence technique. Algae cultures were acclimated to low light (LL, after which the cultures were transferred to high light (HL. Molecular, metabolic and physiological responses were studied at time points 0.5 h, 3 h, 6 h, 12 h, 24 h and 48 h after transfer to HL conditions. The integrated results indicate that the acclimation mechanisms in diatoms can be divided into an initial response phase (0-0.5 h, an intermediate acclimation phase (3-12 h and a late acclimation phase (12-48 h. The initial phase is recognized by strong and rapid regulation of genes encoding proteins involved in photosynthesis, pigment metabolism and reactive oxygen species (ROS scavenging systems. A significant increase in light protecting metabolites occur together with the induction of transcriptional processes involved in protection of cellular structures at this early phase. During the following phases, the metabolite profiling display a pronounced decrease in light harvesting pigments, whereas the variable fluorescence measurements show that the photosynthetic capacity increases strongly during the late acclimation phase. We show that P. tricornutum is capable of swift and efficient execution of photoprotective mechanisms, followed by changes in the composition of the photosynthetic machinery that enable the diatoms to utilize the excess energy available in HL. Central molecular players in light protection and acclimation to high irradiance have been identified.

  5. Sucrose Synthase Expression during Cold Acclimation in Wheat 1

    Science.gov (United States)

    Crespi, Martin D.; Zabaleta, Eduardo J.; Pontis, Horacio G.; Salerno, Graciela L.

    1991-01-01

    When wheat (Triticum aestivum) seedlings are exposed to a cold temperature (2-4°C) above 0°C, sucrose accumulates and sucrose synthase activity increases. The effect of a cold period on the level of sucrose synthase (SS) was investigated. Using antibodies against wheat germ SS, Western blots studies showed that the amount of the SS peptide increased during 14 days in the cold, when plants were moved from 23°C to 4°C. The level of SS diminished when plants were moved back to 23°C. Northern blots of poly(A)+ RNA, confirmed a five- to sixfold induction of SS in wheat leaves during cold acclimation. These results indicate that SS is involved in the plant response to a chilling stress. ImagesFigure 1Figure 2Figure 3 PMID:16668270

  6. Unusual features of the high light acclimation of Chromera velia.

    Science.gov (United States)

    Mann, Marcus; Hoppenz, Paul; Jakob, Torsten; Weisheit, Wolfram; Mittag, Maria; Wilhelm, Christian; Goss, Reimund

    2014-11-01

    In the present study, the high light (HL) acclimation of Chromera velia (Chromerida) was studied. HL-grown cells exhibited an increased cell volume and dry weight compared to cells grown at medium light (ML). The chlorophyll (Chl) a-specific absorption spectra ([Formula: see text]) of the HL cells showed an increased absorption efficiency over a wavelength range from 400 to 750 nm, possibly due to differences in the packaging of Chl a molecules. In HL cells, the size of the violaxanthin (V) cycle pigment pool was strongly increased. Despite a higher concentration of de-epoxidized V cycle pigments, non-photochemical quenching (NPQ) of the HL cells was slightly reduced compared to ML cells. The analysis of NPQ recovery during low light (LL) after a short illumination with excess light showed a fast NPQ relaxation and zeaxanthin epoxidation. Purification of the pigment-protein complexes demonstrated that the HL-synthesized V was associated with the chromera light-harvesting complex (CLH). However, the difference absorption spectrum of HL minus ML CLH, together with the 77 K fluorescence excitation spectra, suggested that the additional V was not protein bound but localized in a lipid phase associated with the CLH. The polypeptide analysis of the pigment-protein complexes showed that one out of three known LHCr proteins was associated in higher concentration with photosystem I in the HL cells, whereas in ML cells, it was enriched in the CLH fraction. In conclusion, the acclimation of C. velia to HL illumination shows features that are comparable to those of diatoms, while other characteristics more closely resemble those of higher plants and green algae.

  7. Early and delayed long-term transcriptional changes and short-term transient responses during cold acclimation in olive leaves

    Science.gov (United States)

    Leyva-Pérez, María de la O; Valverde-Corredor, Antonio; Valderrama, Raquel; Jiménez-Ruiz, Jaime; Muñoz-Merida, Antonio; Trelles, Oswaldo; Barroso, Juan Bautista; Mercado-Blanco, Jesús; Luque, Francisco

    2015-01-01

    Low temperature severely affects plant growth and development. To overcome this constraint, several plant species from regions having a cool season have evolved an adaptive response, called cold acclimation. We have studied this response in olive tree (Olea europaea L.) cv. Picual. Biochemical stress markers and cold-stress symptoms were detected after the first 24 h as sagging leaves. After 5 days, the plants were found to have completely recovered. Control and cold-stressed plants were sequenced by Illumina HiSeq 1000 paired-end technique. We also assembled a new olive transcriptome comprising 157,799 unigenes and found 6,309 unigenes differentially expressed in response to cold. Three types of response that led to cold acclimation were found: short-term transient response, early long-term response, and late long-term response. These subsets of unigenes were related to different biological processes. Early responses involved many cold-stress-responsive genes coding for, among many other things, C-repeat binding factor transcription factors, fatty acid desaturases, wax synthesis, and oligosaccharide metabolism. After long-term exposure to cold, a large proportion of gene down-regulation was found, including photosynthesis and plant growth genes. Up-regulated genes after long-term cold exposure were related to organelle fusion, nucleus organization, and DNA integration, including retrotransposons. PMID:25324298

  8. A systems biology approach for the analysis of carbohydrate dynamics during acclimation to low temperature in Arabidopsis thaliana.

    Science.gov (United States)

    Nägele, Thomas; Kandel, Benjamin A; Frana, Sabine; Meissner, Meike; Heyer, Arnd G

    2011-02-01

    Low temperature is an important environmental factor affecting the performance and distribution of plants. During the so-called process of cold acclimation, many plants are able to develop low-temperature tolerance, associated with the reprogramming of a large part of their metabolism. In this study, we present a systems biology approach based on mathematical modelling to determine interactions between the reprogramming of central carbohydrate metabolism and the development of freezing tolerance in two accessions of Arabidopsis thaliana. Different regulation strategies were observed for (a) photosynthesis, (b) soluble carbohydrate metabolism and (c) enzyme activities of central metabolite interconversions. Metabolism of the storage compound starch was found to be independent of accession-specific reprogramming of soluble sugar metabolism in the cold. Mathematical modelling and simulation of cold-induced metabolic reprogramming indicated major differences in the rates of interconversion between the pools of hexoses and sucrose, as well as the rate of assimilate export to sink organs. A comprehensive overview of interconversion rates is presented, from which accession-specific regulation strategies during exposure to low temperature can be derived. We propose this concept as a tool for predicting metabolic engineering strategies to optimize plant freezing tolerance. We confirm that a significant improvement in freezing tolerance in plants involves multiple regulatory instances in sucrose metabolism, and provide evidence for a pivotal role of sucrose-hexose interconversion in increasing the cold acclimation output. © 2010 The Authors Journal compilation © 2010 FEBS.

  9. De Novo Synthesis and Degradation of Lx and V Cycle Pigments during Shade and Sun Acclimation in Avocado Leaves1

    Science.gov (United States)

    Förster, Britta; Osmond, C. Barry; Pogson, Barry J.

    2009-01-01

    The photoprotective role of the universal violaxanthin cycle that interconverts violaxanthin (V), antheraxanthin (A), and zeaxanthin (Z) is well established, but functions of the analogous conversions of lutein-5,6-epoxide (Lx) and lutein (L) in the selectively occurring Lx cycle are still unclear. We investigated carotenoid pools in Lx-rich leaves of avocado (Persea americana) during sun or shade acclimation at different developmental stages. During sun exposure of mature shade leaves, an unusual decrease in L preceded the deepoxidation of Lx to L and of V to A+Z. In addition to deepoxidation, de novo synthesis increased the L and A+Z pools. Epoxidation of L was exceptionally slow, requiring about 40 d in the shade to restore the Lx pool, and residual A+Z usually persisted overnight. In young shade leaves, the Lx cycle was reversed initially, with Lx accumulating in the sun and declining in the shade. De novo synthesis of xanthophylls did not affect α- and β-carotene pools on the first day, but during long-term acclimation α-carotene pools changed noticeably. Nonetheless, the total change in α- and β-branch carotenoid pools was equal. We discuss the implications for regulation of metabolic flux through the α- and β-branches of carotenoid biosynthesis and potential roles for L in photoprotection and Lx in energy transfer to photosystem II and explore physiological roles of both xanthophyll cycles as determinants of photosystem II efficiency. PMID:19060099

  10. The trade-off between the light-harvesting and photoprotective functions of fucoxanthin-chlorophyll proteins dominates light acclimation in Emiliania huxleyi (clone CCMP 1516).

    Science.gov (United States)

    McKew, Boyd A; Davey, Phillip; Finch, Stewart J; Hopkins, Jason; Lefebvre, Stephane C; Metodiev, Metodi V; Oxborough, Kevin; Raines, Christine A; Lawson, Tracy; Geider, Richard J

    2013-10-01

    Mechanistic understanding of the costs and benefits of photoacclimation requires knowledge of how photophysiology is affected by changes in the molecular structure of the chloroplast. We tested the hypothesis that changes in the light dependencies of photosynthesis, nonphotochemical quenching and PSII photoinactivation arises from changes in the abundances of chloroplast proteins in Emiliania huxleyi strain CCMP 1516 grown at 30 (Low Light; LL) and 1000 (High Light; HL) μmol photons m(-2) s(-1) photon flux densities. Carbon-specific light-saturated gross photosynthesis rates were not significantly different between cells acclimated to LL and HL. Acclimation to LL benefited cells by increasing biomass-specific light absorption and gross photosynthesis rates under low light, whereas acclimation to HL benefited cells by reducing the rate of photoinactivation of PSII under high light. Differences in the relative abundances of proteins assigned to light-harvesting (Lhcf), photoprotection (LI818-like), and the photosystem II (PSII) core complex accompanied differences in photophysiology: specifically, Lhcf:PSII was greater under LL, whereas LI818:PSII was greater in HL. Thus, photoacclimation in E. huxleyi involved a trade-off amongst the characteristics of light absorption and photoprotection, which could be attributed to changes in the abundance and composition of proteins in the light-harvesting antenna of PSII.

  11. Gelation in protein extracts from cold acclimated and non-acclimated winter rye (Secale cereale L. cv Musketeer).

    Science.gov (United States)

    Lim, Ze Long; Low, Nicholas H; Moffatt, Barbara A; Gray, Gordon R

    2013-04-01

    A protein gel is a three-dimensional network consisting of molecular interactions between biopolymers that entrap a significant volume of a continuous liquid phase (water). Molecular interactions in gels occur at junction zones within and between protein molecules through electrostatic forces, hydrogen bonding, hydrophobic associations (van der Waals attractions) and covalent bonding. Gels have the physicochemical properties of both solids and liquids, and are extremely important in the production and stability of a variety of foods, bioproducts and pharmaceuticals. In this study, gelation was induced in phenol extracted protein fractions from non-acclimated (NA) and cold-acclimated (CA) winter rye (Secale cereale L. cv Musketeer) leaf tissue after repeated freeze-thaw treatments. Gel formation only occurred at high pH (pH 12.0) and a minimum of 3-4 freeze-thaw cycles were required. The gel was thermally stable and only a specific combination of chemical treatments could disrupt the gel network. SDS-PAGE analysis identified ribulose-1,5-bisphosphate carboxylase oxygenase (Rubisco) as the major protein component in the gel, although Rubisco itself did not appear to be a factor in gelation. Raman spectroscopy suggested changes in protein secondary structure during freeze-thaw cycles. Overall, the NA and CA gels were similar in composition and structure, with the exception that the CA gel appeared to be amyloidic in nature based on thioflavin T (ThT) fluorescence. Protein gelation, particularly in the apoplast, may confer protection against freeze-induced dehydration and potentially have a commercial application to improve frozen food quality. Copyright © 2013 Elsevier Inc. All rights reserved.

  12. Myo-inositol phosphate synthase expression in the European eel (Anguilla anguilla) and Nile tilapia (Oreochromis niloticus): effect of seawater acclimation.

    Science.gov (United States)

    Kalujnaia, Svetlana; Hazon, Neil; Cramb, Gordon

    2016-08-01

    A single MIPS gene (Isyna1/Ino1) exists in eel and tilapia genomes with a single myo-d-inositol 3-phosphate synthase (MIPS) transcript identified in all eel tissues, although two MIPS spliced variants [termed MIPS(s) and MIPS(l)] are found in all tilapia tissues. The larger tilapia transcript [MIPS(l)] results from the inclusion of the 87-nucleotide intron between exons 5 and 6 in the genomic sequence. In most tilapia tissues, the MIPS(s) transcript exhibits much higher abundance (generally >10-fold) with the exception of white skeletal muscle and oocytes, in which the MIPS(l) transcript predominates. SW acclimation resulted in large (6- to 32-fold) increases in mRNA expression for both MIPS(s) and MIPS(l) in all tilapia tissues tested, whereas in the eel, changes in expression were limited to a more modest 2.5-fold increase and only in the kidney. Western blots identified a number of species- and tissue-specific immunoreactive MIPS proteins ranging from 40 to 67 kDa molecular weight. SW acclimation failed to affect the abundance of any immunoreactive protein in any tissue tested from the eel. However, a major 67-kDa immunoreactive protein (presumed to be MIPS) found in tilapia tissues exhibited 11- and 54-fold increases in expression in gill and fin samples from SW-acclimated fish. Immunohistochemical investigations revealed specific immunoreactivity in the gill, fin, skin, and intestine taken from only SW-acclimated tilapia. Immunofluorescence indicated that MIPS was expressed within gill chondrocytes and epithelial cells of the primary filaments, basal epithelial cell layers of the skin and fin, the cytosol of columnar intestinal epithelial and mucous cells, as well as unknown entero-endocrine-like cells.

  13. Low-temperature effect on enzyme activities involved in sucrose-starch partitioning in salt-stressed and salt-acclimated cotyledons of quinoa (Chenopodium quinoa Willd.) seedlings.

    Science.gov (United States)

    Rosa, Mariana; Hilal, Mirna; González, Juan A; Prado, Fernando E

    2009-04-01

    The effect of low temperature on growth, sucrose-starch partitioning and related enzymes in salt-stressed and salt-acclimated cotyledons of quinoa (Chenopodium quinoa Willd.) was studied. The growth of cotyledons and growing axes in seedlings grown at 25/20 degrees C (light/dark) and shifted to 5/5 degrees C was lower than in those only growing at 25/20 degrees C (unstressed). However, there were no significant differences between low-temperature control and salt-treated seedlings. The higher activities of sucrose phosphate synthase (SPS, EC 2.4.1.14) and soluble acid invertase (acid INV, EC 3.2.1.25) were observed in salt-stressed cotyledons; however, the highest acid INV activity was observed in unstressed cotyledons. ADP-glucose pyrophosphorylase (ADP-GPPase, EC 2.7.7.27) was higher in unstressed cotyledons than in stressed ones. However, between 0 and 4days the highest value was observed in salt-stressed cotyledons. The lowest value of ADP-GPPase was observed in salt-acclimated cotyledons. Low temperature also affected sucrose synthase (SuSy, EC 2.4.1.13) activity in salt-treated cotyledons. Sucrose and glucose were higher in salt-stressed cotyledons, but fructose was essentially higher in low-temperature control. Starch was higher in low-temperature control; however, the highest content was observed at 0day in salt-acclimated cotyledons. Results demonstrated that low temperature induces different responses on sucrose-starch partitioning in salt-stressed and salt-acclimated cotyledons. Data also suggest that in salt-treated cotyledons source-sink relations (SSR) are changed in order to supply soluble sugars and proline for the osmotic adjustment. Relationships between starch formation and SuSy activity are also discussed.

  14. Self-regulating genomic island encoding tandem regulators confers chromatic acclimation to marine Synechococcus

    National Research Council Canada - National Science Library

    Sanfilippo, Joseph E; Nguyen, Adam A; Karty, Jonathan A; Shukla, Animesh; Schluchter, Wendy M; Garczarek, Laurence; Partensky, Frédéric; Kehoe, David M

    2016-01-01

    ..., which are attached to antennae proteins called phycoerythrins. Many strains can alter phycoerythrin chromophore ratios to optimize photon capture in changing blue-green environments using type IV chromatic acclimation (CA4...

  15. Norepinephrine turnover in heart and spleen of 7-, 22-, and 34 C-acclimated hamsters

    Science.gov (United States)

    Jones, S. B.; Musacchia, X. J.

    1976-01-01

    The relationship of norepinephrine (NE) concentration and endogenous turnover rates in both myocardial and spleen tissues in the golden hamster is examined as a function of chronic exposure to either high or low ambient temperatures. Changes in myocardial and spleen NE turnover values are discussed in terms of functional alterations in sympathetic nerve activity and the importance of such changes in temperature acclimation. It is found that acclimation of hamsters to 7 C for 7-10 weeks results in decreased myocardial NE concentration and an apparent increase in myocardial NE turnover. In contrast, exposure to 34 C for 6-8 weeks results in increased myocardial NE concentration and an apparent decrease in NE turnover in both myocardial and spleen tissues. The implication of altered NE synthesis is that sympathetic nerve activity is reduced with heat acclimation and is enhanced with cold acclimation.

  16. Heat shock response of the blue crab Portunus pelagicus:thermal stress and acclimation

    Institute of Scientific and Technical Information of China (English)

    Suhaila Qari

    2014-01-01

    Objective:To determine the effect of prior heat shock on the CTMax of differently acclimated Portunus pelagicus (P. pelagicus) as well as the time course of the changes in CTMax post heat shock. Methods: Crabs P. pelagicus were held in laboratory aquaria in tanks, which were supplied with filtered and aerated seawater. Crabs were acclimated at 20 °C, 25 °C, 30 °C and 35 °C for 3 weeks before their CTMax was determined. The CTMax was recorded for each crab as the median temperature during the 5 min period when a crab was not able to right itself, the average CTMax was calculated. The effect of heat shock on subsequent CTMax was measured. Crabs were heat shocked at temperature 1 °C lower than the CTMax for 20 min, followed by either 0.5 h, 1 h or 1.5 h recovery at 20 °C. The same procedure was repeated at other acclimation temperatures (25 °C, 30 °C and 35 °C). Results: Temperature acclimation of P. pelargicus from 20-35 °C progressively increased the CTMax. Acclimation at 35 °C the CTMax was 42.66 °C, whereas acclimation at 20 °C the CTMax was 39.8 °C. In P. pelagicus acclimated, at 20 °C the CTMax values after heat shock were significantly higher than crabs in control for 30 min, 1 h and 1.5 h after heat shock. In the 25 °C and 30 °C acclimated crabs, the CTMax values after heat shock were significantly higher than control only in 30 min and 1 h after heat shock. No significant differences in 35 °C acclimated crabs between control and heat shocked crabs were found after recovery for 30 min, 1 h, or 1.5 h. Conclusions: Heat shock caused significant rises in the CTMax, however, this increase was progressively reduced with longer recovery times at the acclimation temperature. For 20 °C acclimated crabs, the increased CTMax was still evident after 90 min, but for 25 °C and 30 °C crabs, the response was over after 90 min. Heat shock of 35 °C crabs was problematical, the CTMax gave no increased thermotolerance. It must be concluded that the

  17. Hypohydration and Acclimation: Effects on Hormone Responses to Excercise/Heat Stress.

    Science.gov (United States)

    1983-03-15

    increased rectal temperature and heart rate and decreased sweat rate (19). Gaebelein and Senay (9) also demonstrated an increased physiological cost ( heart ... increased plasma volume associated with heat acclimation (21), assuming that the increased plasma volume would permit an elevated sweat rate and more...AD-A127 855 HYPOHYDRATION AND ACCLIMATION: EFFECTS ON HORMONE i/I RESPONSES TO EXCERCISE /..(U) ARMY RESEARCH INST OF ENVIRONMENTAL MEDICINE NATICK MR

  18. Distinct Testicular Steroidogenic Response Mechanisms Between Neonatal and Adult Heat-Acclimated Male Rats

    Directory of Open Access Journals (Sweden)

    Beata Kurowicka

    2015-03-01

    Full Text Available Background: In comparison to short-term gonad heat exposure, little is known about the molecular mechanisms that regulate testicular steroidogenesis during long-term whole body heat acclimation. Material and Methods: Testicular slices from neonatal (NHA and adult (AHA heat-acclimated Wistar rats were analysed in vitro to assess the mRNA expression and enzymatic activity of steroidogenic enzymes under basal and luteinising hormone (LH or prolactin (PRL stimulated conditions compared with control rats (CR. Furthermore, a de-acclimated group (DA was created by transferring adult NHA rats to control conditions. Results: Heat acclimation significantly increased plasma LH levels in the AHA group and LH and PRL in the NHA group compared with the CR group; however, after heat acclimation, the T and E2 levels did not differ from the control levels. All heat-acclimated groups showed high basal intra-testicular steroid production in vitro. Moreover, basal Cyp11a1 and Hsd3b1 levels were upregulated in vitro in the NHA and DA groups versus the CR group. LH in vitro stimulation upregulated Cyp11a1 expression in the NHA and AHA groups and PRL stimulation upregulated Cyp17a1 levels in the NHA and DA groups compared with the basal expression levels. In the AHA group, decreased basal Star and CYP11A activities but increased HSD3B1 and CYP17A1 activities were found. Conclusion: Our data revealed that despite the similar steroid levels in plasma and secreted in vitro by neonatal and adult heat-acclimated rat testicular slices, the molecular mechanisms underlying the steroidogenic response to heat acclimation during these different developmental stages were distinct.

  19. UVR8 mediated plant protective responses under low UV-B radiation leading to photosynthetic acclimation.

    Science.gov (United States)

    Singh, Suruchi; Agrawal, S B; Agrawal, Madhoolika

    2014-08-01

    The UV-B photoreceptor UVR8 regulates the expression of several genes leading to acclimation responses in plants. Direct role of UVR8 in maintaining the photosynthesis is not defined but it is known to increase the expression of some chloroplastic proteins like SIG5 and ELIP. It provides indirect protection to photosynthesis by regulating the synthesis of secondary metabolites and photomorphogenesis. Signaling cascades controlled by UVR8 mediate many protective responses thus promotes plant acclimation against stress and secures its survival.

  20. Boreal and temperate trees show strong acclimation of respiration to warming.

    Science.gov (United States)

    Reich, Peter B; Sendall, Kerrie M; Stefanski, Artur; Wei, Xiaorong; Rich, Roy L; Montgomery, Rebecca A

    2016-03-31

    Plant respiration results in an annual flux of carbon dioxide (CO2) to the atmosphere that is six times as large as that due to the emissions from fossil fuel burning, so changes in either will impact future climate. As plant respiration responds positively to temperature, a warming world may result in additional respiratory CO2 release, and hence further atmospheric warming. Plant respiration can acclimate to altered temperatures, however, weakening the positive feedback of plant respiration to rising global air temperature, but a lack of evidence on long-term (weeks to years) acclimation to climate warming in field settings currently hinders realistic predictions of respiratory release of CO2 under future climatic conditions. Here we demonstrate strong acclimation of leaf respiration to both experimental warming and seasonal temperature variation for juveniles of ten North American tree species growing for several years in forest conditions. Plants grown and measured at 3.4 °C above ambient temperature increased leaf respiration by an average of 5% compared to plants grown and measured at ambient temperature; without acclimation, these increases would have been 23%. Thus, acclimation eliminated 80% of the expected increase in leaf respiration of non-acclimated plants. Acclimation of leaf respiration per degree temperature change was similar for experimental warming and seasonal temperature variation. Moreover, the observed increase in leaf respiration per degree increase in temperature was less than half as large as the average reported for previous studies, which were conducted largely over shorter time scales in laboratory settings. If such dampening effects of leaf thermal acclimation occur generally, the increase in respiration rates of terrestrial plants in response to climate warming may be less than predicted, and thus may not raise atmospheric CO2 concentrations as much as anticipated.

  1. Effects of acclimation to handling on performance, reproductive, and physiological responses of Brahman-crossbred heifers.

    Science.gov (United States)

    Cooke, R F; Arthington, J D; Austin, B R; Yelich, J V

    2009-10-01

    The objective of this study was to evaluate the effects of acclimation to handling on growth, plasma concentrations of progesterone (P4) and cortisol, temperament, and reproductive performance of Brahman-crossbred heifers. Over 2 consecutive years, 37 Braford and 43 Brahman x Angus heifers were initially evaluated, within 30 d after weaning, for BW and puberty status via transrectal ultrasonography and plasma P4 concentrations (d 0 and 10), and for temperament by measurements of chute score, pen score, and exit velocity (d 10 only). On d 11, heifers were stratified by breed, puberty status, temperament score, BW, and age and randomly assigned to receive or not (control) the acclimation treatment. Acclimated heifers were exposed to a handling process 3 times weekly (Mondays, Wednesdays, and Fridays) for 4 wk (d 11 to 39 of the experiment). The acclimation treatment was applied individually to heifers by processing them through a handling facility, whereas control heifers remained undisturbed on pasture. Heifer puberty status, evaluated via plasma P4 concentrations and transrectal ultrasonography, and BW were assessed again on d 40 and 50, d 80 and 90, and d 120 and 130. Blood samples collected before (d 10) and at the end of the acclimation period (d 40) were also analyzed for plasma concentrations of cortisol. Heifer temperament was assessed again on d 40 of the study. No interactions containing the effects of treatment, breed, and year were detected. Acclimated heifers had reduced (P Brahman-crossbred heifers.

  2. Phosphoprotein SAK1 is a regulator of acclimation to singlet oxygen in Chlamydomonas reinhardtii.

    Science.gov (United States)

    Wakao, Setsuko; Chin, Brian L; Ledford, Heidi K; Dent, Rachel M; Casero, David; Pellegrini, Matteo; Merchant, Sabeeha S; Niyogi, Krishna K

    2014-05-23

    Singlet oxygen is a highly toxic and inevitable byproduct of oxygenic photosynthesis. The unicellular green alga Chlamydomonas reinhardtii is capable of acclimating specifically to singlet oxygen stress, but the retrograde signaling pathway from the chloroplast to the nucleus mediating this response is unknown. Here we describe a mutant, singlet oxygen acclimation knocked-out 1 (sak1), that lacks the acclimation response to singlet oxygen. Analysis of genome-wide changes in RNA abundance during acclimation to singlet oxygen revealed that SAK1 is a key regulator of the gene expression response during acclimation. The SAK1 gene encodes an uncharacterized protein with a domain conserved among chlorophytes and present in some bZIP transcription factors. The SAK1 protein is located in the cytosol, and it is induced and phosphorylated upon exposure to singlet oxygen, suggesting that it is a critical intermediate component of the retrograde signal transduction pathway leading to singlet oxygen acclimation.DOI: http://dx.doi.org/10.7554/eLife.02286.001.

  3. Phosphoprotein SAK1 is a regulator of acclimation to singlet oxygen in Chlamydomonas reinhardtii

    Science.gov (United States)

    Wakao, Setsuko; Chin, Brian L; Ledford, Heidi K; Dent, Rachel M; Casero, David; Pellegrini, Matteo; Merchant, Sabeeha S; Niyogi, Krishna K

    2014-01-01

    Singlet oxygen is a highly toxic and inevitable byproduct of oxygenic photosynthesis. The unicellular green alga Chlamydomonas reinhardtii is capable of acclimating specifically to singlet oxygen stress, but the retrograde signaling pathway from the chloroplast to the nucleus mediating this response is unknown. Here we describe a mutant, singlet oxygen acclimation knocked-out 1 (sak1), that lacks the acclimation response to singlet oxygen. Analysis of genome-wide changes in RNA abundance during acclimation to singlet oxygen revealed that SAK1 is a key regulator of the gene expression response during acclimation. The SAK1 gene encodes an uncharacterized protein with a domain conserved among chlorophytes and present in some bZIP transcription factors. The SAK1 protein is located in the cytosol, and it is induced and phosphorylated upon exposure to singlet oxygen, suggesting that it is a critical intermediate component of the retrograde signal transduction pathway leading to singlet oxygen acclimation. DOI: http://dx.doi.org/10.7554/eLife.02286.001 PMID:24859755

  4. Interaction between heat acclimation and exogenous insulin in brown adipose tissue of rats

    Science.gov (United States)

    Ohno, H.; Yamashita, H.; Sato, N.; Habara, Y.; Gasa, S.; Nagasawa, J.; Sato, Y.; Ishikawa, M.; Segawa, M.; Yamamoto, M.

    1992-09-01

    Seventy-one male Wistar strain rats (7 weeks old) were kept at 5, 25, or 34° C, respectively, for 2 weeks with or without insulin administration. Insulin (Novo Lente MC) was given subcutaneously in a dose of 3.62 nmol/125 µl saline per 100 g body weight. An apparent effect of insulin treatment was noted only in heat-exposed rats, resulting in a remarkable gain in inter-scapular brown adipose tissue (BAT) mass of heat-acclimated, insulin-treated rats in terms of weight or weight per unit body weight. The BAT from heat-acclimated, insulin-treated rats had significantly higher levels of protein, DNA, RNA, and triglyceride than BAT from heat-acclimated, saline-treated rats. Therefore, it seems likely that the growth of BAT in heat-acclimated, insulin-treated rats was mostly due to the anabolic effects of insulin. The uncoupling protein mRNA was, however, present in BAT of heat-acclimated, insulin-treated rats at rather a depressed level, explaining a corresponding decrease in cold tolerance. On the other hand, the expression of insulin receptor mRNA was attenuated in BAT of rats from all the insulin-treated groups, possibly due to the down-regulation of insulin. Thus, there appeared to be some linkage among BAT, heat acclimation, and insulin.

  5. Swimming performance and thermal resistance of juvenile and adult newts acclimated to different temperatures

    Directory of Open Access Journals (Sweden)

    Hong-Liang Lu

    2016-12-01

    Full Text Available Thermal acclimatory adjustments of locomotor performance and thermal tolerance occur commonly in ectothermic animals. However, few studies have investigated ontogenetic differences in these acclimatory responses, and thus, their causes remain unclear. In this study, juvenile and adult Chinese fire-bellied newts (Cynops orientalis were acclimated to one of two temperatures (16 or 24 °C for 4 weeks to examine ontogenetic differences in acclimation effect on burst swimming speed, and critical thermal minimum (CTMin and maximum (CTMax. Swimming performance was thermally acclimated in both juvenile and adult C. orientalis. Adult newts had greater absolute swimming speeds than juveniles, which may simply result from their larger sizes. Cold acclimation enhanced low-temperature resistance, and warm acclimation enhanced high-temperature resistance in both juveniles and adults. Despite no ontogenetic difference in CTMin, adult newts had greater CTMax and acclimation response ratio than juveniles, indicating their greater abilities to withstand extreme high temperatures and manage rapid temperature shifts. Ontogenetic change in the thermal acclimatory responses of newts may be related to changes in the thermal environment they experience.

  6. The impact of anode acclimation strategy on microbial electrolysis cell treating hydrogen fermentation effluent.

    Science.gov (United States)

    Li, Xiaohu; Zhang, Ruizhe; Qian, Yawei; Angelidaki, Irini; Zhang, Yifeng

    2017-07-01

    The impact of different anode acclimation methods for enhancing hydrogen production in microbial electrolysis cell (MEC) was investigated in this study. The anodes were first acclimated in microbial fuel cells using acetate, butyrate and corn stalk fermentation effluent (CSFE) as substrate before moving into MECs, respectively. Subsequently, CSFE was used as feedstock in all the three MECs. The maximum hydrogen yield with the anode pre-acclimated with butyrate (5.21±0.24L H2/L CSFE) was higher than that pre-acclimated with acetate (4.22±0.19L H2/L CSFE) and CSFE (4.55±0.14L H2/L CSFE). The current density (480±11A/m(3)) and hydrogen production rate (4.52±0.13m(3)/m(3)/d) with the anode pre-acclimated with butyrate were also higher that another two reactors. These results demonstrated that the anode biofilm pre-acclimated with butyrate has significant advantages in CSFE treatment and could improve the performance of hydrogen production in MEC. Copyright © 2017 Elsevier Ltd. All rights reserved.

  7. Effect of pre-acclimation of granular activated carbon on microbial electrolysis cell startup and performance.

    Science.gov (United States)

    LaBarge, Nicole; Yilmazel, Yasemin Dilsad; Hong, Pei-Ying; Logan, Bruce E

    2017-02-01

    Microbial electrolysis cells (MECs) can generate methane by fixing carbon dioxide without using expensive catalysts, but the impact of acclimation procedures on subsequent performance has not been investigated. Granular activated carbon (GAC) was used to pre-enrich electrotrophic methanogenic communities, as GAC has been shown to stimulate direct transfer of electrons between different microbial species. MEC startup times using pre-acclimated GAC were improved compared to controls (without pre-acclimation or without GAC), and after three fed batch cycles methane generation rates were similar (P>0.4) for GAC acclimated to hydrogen (22±9.3nmolcm(-3)d(-1)), methanol (25±9.7nmolcm(-3)d(-1)), and a volatile fatty acid (VFA) mix (22±11nmolcm(-3)d(-1)). However, MECs started with GAC but no pre-acclimation had lower methane generation rates (13±4.1nmolcm(-3)d(-1)), and MECs without GAC had the lowest rates (0.7±0.8nmolcm(-3)d(-1) after cycle 2). Microbes previously found in methanogenic MECs, or previously shown to be capable of exocellular electron transfer, were enriched on the GAC. Pre-acclimation using GAC is therefore a simple approach to enrich electroactive communities, improve methane generation rates, and decrease startup times in MECs. Copyright © 2016 Elsevier B.V. All rights reserved.

  8. Seasonal acclimation of preferred body temperatures improves the opportunity for thermoregulation in newts.

    Science.gov (United States)

    Hadamová, Markéta; Gvoždík, Lumír

    2011-01-01

    Seasonal acclimation and thermoregulation represent major components of complex thermal strategies by which ectotherms cope with the heterogeneity of their thermal environment. Some ectotherms possess the acclimatory capacity to shift seasonally their thermoregulatory behavior, but the frequent use of constant acclimation temperatures during experiments and the lack of information about thermal heterogeneity in the field obscures the ecological relevance of this plastic response. We examined the experimentally induced seasonal acclimation of preferred body temperatures (T(p)) in alpine newts Ichthyosaura (formerly Triturus) alpestris subjected to a gradual increase in acclimation temperature from 5°C during the winter to a constant 15°C or diel fluctuations between 10° and 20°C during the spring/summer. Both the mean and range of T(p) followed the increase in mean acclimation temperature without the influence of diel temperature fluctuations. The direction and magnitude of this acclimatory capacity has the potential to increase the time window available for thermoregulation. Although thermoregulation and thermal acclimation are often considered as separate but coadapted adjustments to thermal heterogeneity, their combined response is employed by newts to tackle seasonal variation in a thermoregulatory-challenging aquatic environment.

  9. Thioredoxins Play a Crucial Role in Dynamic Acclimation of Photosynthesis in Fluctuating Light.

    Science.gov (United States)

    Thormählen, Ina; Zupok, Arkadiusz; Rescher, Josephin; Leger, Jochen; Weissenberger, Stefan; Groysman, Julia; Orwat, Anne; Chatel-Innocenti, Gilles; Issakidis-Bourguet, Emmanuelle; Armbruster, Ute; Geigenberger, Peter

    2017-01-09

    Sunlight represents the energy source for photosynthesis and plant growth. When growing in the field, plant photosynthesis has to manage strong fluctuations in light intensities. Regulation based on the thioredoxin (Trx) system is believed to ensure light-responsive control of photosynthetic reactions in the chloroplast. However, direct evidence for a role of this system in regulating dynamic acclimation of photosynthesis in fluctuating conditions is largely lacking. In this report we show that the ferredoxin-dependent Trxs m1 and m2 as well as the NADPH-dependent NTRC are both indispensable for photosynthetic acclimation in fluctuating light intensities. Arabidopsis mutants with combined deficiency in Trxs m1 and m2 show wild-type growth and photosynthesis under constant light condition, while photosynthetic parameters are strongly modified in rapidly alternating high and low light. Two independent trxm1m2 mutants show lower photosynthetic efficiency in high light, but surprisingly significantly higher photosynthetic efficiency in low light. Our data suggest that a main target of Trx m1 and m2 is the NADP-malate dehydrogenase involved in export of excess reductive power from the chloroplast. The decreased photosynthetic efficiency in the high-light peaks may thus be explained by a reduced capacity of the trxm1m2 mutants in the rapid light activation of this enzyme. In the ntrc mutant, dynamic responses of non-photochemical quenching of excitation energy and plastoquinone reduction state both were strongly attenuated in fluctuating light intensities, leading to a massive decrease in PSII quantum efficiency and a specific decrease in plant growth under these conditions. This is likely due to the decreased ability of the ntrc mutant to control the stromal NADP(H) redox poise. Taken together, our results indicate that NTRC is indispensable in ensuring the full range of dynamic responses of photosynthesis to optimize photosynthesis and maintain growth in fluctuating

  10. An isotopomer strategy to detect plant acclimation to increasing atmospheric CO2

    Science.gov (United States)

    Augusti, A.; Betson, T. R.; Schleucher, J.

    2009-04-01

    Abundances of deuterium (D) and 18O in precipitation carry climate signals. Both isotopes are incorporated into leaf photosynthate, and in a second step into tree rings. Strikingly, while D and 18O climate signals in precipitation are related, tree-ring records of both isotopes do not generally go in parallel. This contribution investigates this discrepancy, based on a comparison of the fractionation mechanisms for both isotopes. We present a strategy to detect plant acclimation on time scales of centuries from intramolecular deuterium distributions (D isotopomers). We showed recently that specific C-H groups of glucose units exchange with water during cellulose synthesis in tree trunks, in agreement with the biochemistry of cellulose formation. Most importantly, this result allows separating influences of source water and of D fractionations in the plant, and hence to isolate climate signals and physiological signals. NMR measurements of intramolecular D distributions of glucose demonstrate that each C-H group has a distinct abundance (each D isotopomer), corresponding to its unique biochemical history, and can serve as independent information channel. Therefore, isotopomers increase the information content of isotopes several-fold. Thus, using D isotopomers, a situation may be achieved where experimental quantities overdetermine the number of variables to be reconstructed. This increased information content can be retrieved along the following strategies. Similar to C-O groups that exchange during cellulose synthesis, D isotopomers of C-H groups which heavily exchange should adopt the D abundance of source water and associated climate signals. We will present tree-ring results that support the feasibility of this approach. C-H groups that are not affected by isotope exchange are passed from leaves to the trunk, and can therefore transmit leaf-level information to tree rings. On the leaf level, overall D abundance of photosynthate is influenced by transpiration

  11. Toxic effects of the herbicide Roundup in the guppy Poecilia vivipara acclimated to fresh water.

    Science.gov (United States)

    Harayashiki, Cyntia Ayumi Yokota; Varela, Antonio Sergio; Machado, Anderson Abel de Souza; Cabrera, Liziara da Costa; Primel, Ednei Gilberto; Bianchini, Adalto; Corcini, Carine Dahl

    2013-10-15

    Although it is believed that glyphosate-based herbicides are relatively nontoxic to humans, its broad use in agriculture and consequent contamination of aquatic systems is a concern. In the present study, reproductive (sperm quality) and biochemical parameters (acetylcholinesterase and glutathione S-transferase activity, lipoperoxidation, and antioxidant capacity against peroxyl radicals) were evaluated in adult guppies (Poecilia vivipara) acclimated to fresh water and exposed (96 h) to environmentally realistic concentrations of glyphosate (130 and 700 μg L(-1)) as the commercial formulation Roundup. Male guppies exposed to Roundup showed a poorer sperm quality, measured as reduced plasmatic membrane integrity, mitochondrial functionality, DNA integrity, motility, motility period and concentration of spermatic cells, than those kept under control condition (no Roundup addition to the water). Most of the spermatic parameters analyzed showed strong association to each other, which may help to understand the mechanisms underlying the observed reduction in sperm quality. Exposure to Roundup did not alter the biochemical parameters analyzed, though differences between genders were observed and deserve further investigations. Findings from the present study suggest that exposure to environmentally relevant concentrations of Roundup may negatively affect at long-term the reproduction of P. vivipara, with consequent changes in fish populations inhabiting environments contaminated with the herbicide.

  12. Acclimation and soil moisture constrain sugar maple root respiration in experimentally warmed soil.

    Science.gov (United States)

    Jarvi, Mickey P; Burton, Andrew J

    2013-09-01

    The response of root respiration to warmer soil can affect ecosystem carbon (C) allocation and the strength of positive feedbacks between climatic warming and soil CO2 efflux. This study sought to determine whether fine-root (respiration in a sugar maple (Acer saccharum Marsh.)-dominated northern hardwood forest would adjust to experimentally warmed soil, reducing C return to the atmosphere at the ecosystem scale to levels lower than that would be expected using an exponential temperature response function. Infrared heating lamps were used to warm the soil (+4 to +5 °C) in a mature sugar maple forest in a fully factorial design, including water additions used to offset the effects of warming-induced dry soil. Fine-root-specific respiration rates, root biomass, root nitrogen (N) concentration, soil temperature and soil moisture were measured from 2009 to 2011, with experimental treatments conducted from late 2010 to 2011. Partial acclimation of fine-root respiration to soil warming occurred, with soil moisture deficit further constraining specific respiration rates in heated plots. Fine-root biomass and N concentration remained unchanged. Over the 2011 growing season, ecosystem root respiration was not significantly greater in warmed soil. This result would not be predicted by models that allow respiration to increase exponentially with temperature and do not directly reduce root respiration in drier soil.

  13. Effect of neonatal or adult heat acclimation on plasma fT3 level, testicular thyroid receptors expression in male rats and testicular steroidogenesis in vitro in response to triiodothyronine treatment.

    Science.gov (United States)

    Kurowicka, B; Chrusciel, M; Zmijewska, A; Kotwica, G

    2016-01-01

    This study aimed to evaluate the effect of heat acclimation of neonatal and adult rats on their testes response to in vitro treatment with triiodothyronine (T3). Four groups of rats were housed from birth as: 1) control (CR) at 20°C for 90 days, 2) neonatal heat-acclimated (NHA) at 34°C for 90 days, 3) adult heat-acclimated (AHA) at 20°C for 45 days followed by 45 days at 34°C and 4) de-acclimated (DA) at 34°C for 45 days followed by 45 days at 20°C. Blood plasma and both testes were harvested from 90-day old rats. Testicular slices were then submitted to in vitro treatment with T3 (100 ng/ml) for 8 h. Plasma fT3 level was lower in AHA, NHA and DA groups than in CR group. Basal thyroid hormone receptor α1 (Thra1) expression was higher in testes of NHA and DA and β1 receptor (Thrb1) in DA rats vs. other groups. In the in vitro experiment, T3: 1) decreased Thra1 expression in all groups and Thrb1 in DA group, 2) increased Star expression in CR, NHA and DA groups, and Hsd17b3 expression in NHA group, 3) decreased the expression of Cyp11a1 in NHA and DA groups, and Cyp19a1 in all the groups, 4) did not affect the activity of steroidogenic enzymes and steroid secretion (A4, T, E2) in all the groups. These results indicate, that heat acclimation of rats, depending on their age, mainly affects the testicular expression of steroidogenic enzymes in response to short-lasting treatment with T3.

  14. Molecular programs induced by heat acclimation confer neuroprotection against TBI and hypoxic insults via cross-tolerance mechanisms

    Directory of Open Access Journals (Sweden)

    Michal eHorowitz

    2015-07-01

    Full Text Available Neuroprotection following prolonged exposure to high ambient temperatures (heat acclimation HA develops via altered molecular programs such as cross-tolerance (Heat Acclimation -Neuroprotection Cross-Tolerance -HANCT. The mechanisms underlying cross-tolerance depend on enhanced on-demand protective pathways evolving during acclimation. The protection achieved is long lasting and limits the need for de novo recruitment of cytoprotective pathways upon exposure to novel stressors. Using mouse and rat acclimated phenotypes, we will focus on the impact of heat acclimation on Angiotensin II-AT2 receptors in neurogenesis and on HIF-1 as key mediators in spontaneous recovery and HANCT after traumatic brain injury (TBI. The neuroprotective consequences of heat acclimation on NMDA and AMPA receptors will be discussed using the global hypoxia model. A behavioral-molecular link will be crystallized. The differences between HANCT and consensus preconditioning will be reviewed.

  15. Transcriptome characterization of Ishige okamurae (Phaeophyceae) shows strong environmental acclimation

    Institute of Scientific and Technical Information of China (English)

    QU Jieqiong; WANG Xumin; CHI Shan; WU Shuangxiu; SUN Jing; LIU Cui; CHEN Shengping; YU Jun; LIU Tao

    2014-01-01

    Ishige okamurae, with leathery branched narrow fronds consisting of cylindrical hairs, is the typical species of the genus Ishige, which is considered as one of the most basal genera in the phylogeny of the Phaeophy-ceae. Apart from great public interest from the evolutionary respect, more attention has been brought on the abundant bioactive compounds in I. okamurae for therapeutic or economic considerations, such as di-phlorethohydroxycarmalol and ishigoside. Yet little is known about related key genes or metabolic pathways involved in I. okamurae, which calls upon us to carry out global analyses of transcriptome by next generation sequencing. Altogether, we obtained 78 583 assembled scaffolds with N50 of 1 709 nucleotides, and 25 357 unigenes with significant BLAST matches (E-value cutoff of 10-5). In terms of characterization of the tran-scriptome of I. okamurae, we focused on anti-stress metabolic pathways and synthetic routes of bioactive compounds in an attempt to obtain a better understanding of the interactive organism-environment regula-tory networks. Pathway-based analysis helped us to deepen our comprehension of the interaction between I. okamurae and its surroundings, with MAPK signal pathway as an example. Furthermore, we discovered a wide range of novel putative functional proteins that could be of wide application, such as Rab family, using sequence-based transcriptome. In conclusion, transcriptome characterization of I. okamurae (Phaeophy-ceae) shows strong environmental acclimation.

  16. Temporal heterogeneity of cold acclimation phenotypes in Arabidopsis leaves.

    Science.gov (United States)

    Gorsuch, Peter A; Pandey, Subedar; Atkin, Owen K

    2010-02-01

    To predict the effects of temperature changes on plant growth and performance, it is crucial to understand the impact of thermal history on leaf morphology, anatomy and physiology. Here, we document a comprehensive range of leaf phenotypes in 25/20 degrees C-grown Arabidopsis thaliana plants that were shifted to 5 degrees C for up to 2 months. When warm-grown, pre-existing (PE) leaves were exposed to cold, leaf thickness increased due to an increase in mesophyll cell size. Leaves that were entirely cold-developed (CD) were twice as thick (eight cell layers) as their warm-developed (WD) counterparts (six layers), and also had higher epidermal and stomatal cell densities. After 4 d of cold, PE leaves accumulated high levels of total non-structural carbohydrates (TNC). However, glucose and starch levels declined thereafter, and after 45 d in the cold, PE leaves exhibited similar TNC to CD leaves. A similar phenomenon was observed in delta(13)C and a range of photosynthetic parameters. In cold-treated PE leaves, an increase in respiration (R(dark)) with cold exposure time was evident when measured at 25 degrees C but not 5 degrees C. Cold acclimation was associated with a large increase in the ratio of leaf R(dark) to photosynthesis. The data highlight the importance of understanding developmental thermal history in determining individual phenotypic traits.

  17. INHIBITION KINETICS DURING THE OXIDATION OF BINARY MIXTURES OF PHENOL WITH CATECHOL, RESORCINOL AND HYDROQUINONE BY PHENOL ACCLIMATED ACTIVATED SLUDGE

    Directory of Open Access Journals (Sweden)

    C. C. Lobo

    Full Text Available Abstract In this work the aerobic degradation of phenol (PH, catechol (CA, resorcinol (RE, hydroquinone (HY and of the binary mixtures PH+CA, PH+RE, PH+HY by phenol-acclimated activated sludge was studied. Single substrate experiments show a Haldane-type dependence of the respiration rate on PH, RE and HY, while CA corresponded to the Monod model. Binary substrate experiments demonstrated that the presence of a second substrate only affected the kinetics, but not the stoichiometry of the oxidation of the compounds tested. While CA inhibited the oxidation of PH, PH inhibited the oxidation of RE and HY. A mathematical model was developed to represent the aerobic biodegradation of the phenolic compounds tested. The agreement between the proposed model and the experimental data indicates that the proposed model can be useful for predicting substrate and dissolved oxygen concentrations in bioreactors treating phenolic wastewaters.

  18. Study of the Effect of SRT on Microbial Diversity in Laboratory-scale Sequencing Batch Reactors Using Acclimated and Non-Acclimated Seed

    KAUST Repository

    Tellez, Berenice

    2011-07-07

    Solids Retention Time (SRT) is an important design parameter in activated sludge wastewater treatment systems. In this study, the effect of SRT on the bacterial community structure and diversity was examined in replicate lab-scale activated sludge sequencing batch reactors were operated for a period of 8 weeks and seeded with acclimated or non-acclimated sludge. Four SBRs (acclimated) were set up as duplicates and operated at an SRT of 2 days, and another set of four SBRs (non-acclimated) were operated at an SRT of 10 days. To characterize the microbial community in the SBRs, 16S rRNA gene pyrosequencing was used to measure biodiversity and to assess the reproducibility and stability of the bacterial community structure in replicate reactors. Diversity results showed that SBRs operated at an SRT of 10 days are more diverse than SBRs operated at an SRT of 2 days. This suggests that engineering decision could enhance diversity in activated sludge systems. Cluster analysis based on phylogenetic information revealed that the bacterial community structure was not stable and replicated SBRs evolved differently.

  19. A novel technology for quick acclimation of an anaerobic microbial consortia used for biodegrading teraphthalic acid(TA)

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    The seed sludge originated from a methane fermentation reactor was enriched and acclimated with TA as sole carbon source under nitrate respiration mode first for 6 week, and then can be turned to methane fermentation conditions. After 6 weeks processing, the specific rate acclimation. Aftera total of 90 days for the enrichment and acclimation, the fermentative bacteria which originally existed in the seed sludge nearly disappeared, and instead of them, the TA reductive and cleaving bacteria group was formed in the new consortia, which was confirmed by the MPN counts and roll tube counts. Compared with the control experiment, the acclimation period can be shortened by about 50%.

  20. Effect of thermal acclimation on action potentials and sarcolemmal K+ channels from Pacific bluefin tuna cardiomyocytes.

    Science.gov (United States)

    Galli, G L J; Lipnick, M S; Block, B A

    2009-08-01

    To sustain cardiac muscle contractility relatively independent of temperature, some fish species are capable of temporarily altering excitation-contraction coupling processes to meet the demands of their environment. The Pacific bluefin tuna, Thunnus orientalis, is a partially endothermic fish that inhabits a wide range of thermal niches. The present study examined the effects of temperature and thermal acclimation on sarcolemmal K(+) currents and their role in action potential (AP) generation in bluefin tuna cardiomyocytes. Atrial and ventricular myocytes were enzymatically isolated from cold (14 degrees C)- and warm (24 degrees C)-acclimated bluefin tuna. APs and current-voltage relations of K(+) channels were measured using the whole cell current and voltage clamp techniques, respectively. Data were collected either at the cardiomyocytes' respective acclimation temperature of 14 or 24 degrees C or at a common test temperature of 19 degrees C (to reveal the effects of acclimation). AP duration (APD) was prolonged in cold-acclimated (CA) cardiomyocytes tested at 14 degrees C compared with 19 degrees C and in warm-acclimated (WA) cardiomyocytes tested at 19 degrees C compared with 24 degrees C. This effect was mirrored by a decrease in the density of the delayed-rectifier current (I(Kr)), whereas the density of the background inward-rectifier current (I(K1)) was unchanged. When CA and WA cardiomyocytes were tested at a common temperature of 19 degrees C, no significant effects of temperature acclimation on AP shape or duration were observed, whereas I(Kr) density was markedly increased in CA cardiomyocytes. I(K1) density was unaffected in CA ventricular myocytes but was significantly reduced in CA atrial myocytes, resulting in a depolarization of atrial resting membrane potential. Our results indicate the bluefin AP is relatively short compared with other teleosts, which may allow the bluefin heart to function at cold temperatures without the necessity for thermal

  1. Progressive acclimation alters interaction between salinity and temperature in experimental Daphnia populations.

    Science.gov (United States)

    Loureiro, Cláudia; Cuco, Ana P; Claro, Maria Teresa; Santos, Joana I; Pedrosa, M Arminda; Gonçalves, Fernando; Castro, Bruno B

    2015-11-01

    Environmental stressors rarely act in isolation, giving rise to interacting environmental change scenarios. However, the impacts of such interactions on natural populations must consider the ability of organisms to adapt to environmental changes. The phenotypic adaptability of a Daphnia galeata clone to temperature rise and salinisation was investigated in this study, by evaluating its halotolerance at two different temperatures, along a short multigenerational acclimation scenario. Daphniids were acclimated to different temperatures (20°C and 25°C) and salinities (0gL(-1) and 1gL(-1), using NaCl as a proxy) in a fully crossed design. The objective was to understand whether acclimation to environmental stress (combinations of temperature and salinity) influenced the response to the latter exposure to these stressors. We hypothesize that acclimation to different temperature×salinity regimes should elicit an acclimation response of daphniids to saline stress or its interaction with temperature. Acute (survival time) and chronic (juvenile growth) halotolerance measures were obtained at discrete timings along the acclimation period (generations F1, F3 and F9). Overall, exposure temperature was the main determinant of the acute and chronic toxicity of NaCl: daphniid sensitivity (measured as the decrease of survival time or juvenile growth) was consistently higher at the highest temperature, irrespective of background conditions. However, this temperature-dependent effect was nullified after nine generations, but only when animals had been acclimated to both stressors (high salinity and high temperature). Such complex interaction scenarios should be taken in consideration in risk assessment practices.

  2. Hypoxia acclimation and subsequent reoxygenation partially prevent Mn-induced damage in silver catfish.

    Science.gov (United States)

    Dolci, G S; Rosa, H Z; Barcelos, R C S; Vey, L T; Santos, A; DallaVechia, P; Bizzi, C; Cunha, M A; Baldisserotto, B; Burger, M E

    2017-01-01

    This study investigated if hypoxia acclimation modifies the hematological and oxidative profiles in tissues of Mn-exposed silver catfish (Rhamdia quelen), and if such modifications persist upon subsequent reoxygenation. Silver catfish acclimated to hypoxia (~3mgL(-1)) for 10days and subsequently exposed to Mn (~8.1mgL(-1)) for additional 10days exhibited lower Mn accumulation in plasma, liver and kidney, even after reoxygenation, as compared to normoxia-acclimated fish. Hypoxia acclimation increased per se red blood cells count and hematocrit, suggesting adaptations under hypoxia, while the reoxygenation process was also related to increased hematocrit and hemoglobin per se. Fish exposed to Mn under normoxia for 20days showed decreased red blood cells count and hematocrit, while reoxygenation subsequent to hypoxia increased red blood cells count. Hypoxia acclimation also prevented Mn-induced oxidative damage, observed by increased reactive species generation and higher protein carbonyl levels in both liver and kidney under normoxia. Mn-exposed fish under hypoxia and after reoxygenation showed decreased plasma transaminases in relation to the normoxia group. Moreover, acclimation to hypoxia increased reduced glutathione levels, catalase activity and Na(+)/K(+)-ATPase activity in liver and kidney during Mn exposure, remaining increased even after reoxygenation. These findings show that previous acclimation to hypoxia generates physiological adjustments, which drive coordinated responses that ameliorate the antioxidant status even after reoxygenation. Such responses represent a physiological regulation of this teleost fish against oxygen restriction and/or Mn toxicity in order to preserve the stability of a particular tissue or system. Copyright © 2016 Elsevier Inc. All rights reserved.

  3. Fresh water acclimation elicits a decrease in plasma corticosteroids in the euryhaline Atlantic stingray, Dasyatis sabina.

    Science.gov (United States)

    Evans, Andrew N; Nunez, B Scott

    2015-10-01

    It is thought that the elasmobranch corticosteroid hormone 1α-hydroxycorticosterone (1α-B) functions as both a glucocorticoid (GC) and mineralocorticoid (MC). Classical antinatriuretic MC activities would run counter to the osmoregulatory strategy of euryhaline elasmobranchs acclimating to fresh water (FW). Therefore we hypothesize that FW acclimation will be accompanied by a decrease in plasma corticosteroids in these animals. However, events that activate the "fight-or-flight" response could mask changes associated with acclimation to lower salinities. To better define the MC role of corticosteroids in elasmobranchs, we designed a transfer system that allows the acclimation of Atlantic stingrays (Dasyatis sabina) from seawater (SW) to FW over 12h while minimizing other extraneous stressors. Blood and interrenal glands were sampled from one group of stingrays 24h after FW transfer, while another group was sampled two weeks after FW transfer. Two other groups served as mock-transfer controls in that they were treated and sampled in the same way, but remained in SW for the entire period. Plasma corticosteroids, osmolality, chloride, and urea were significantly lower in FW-acclimated stingrays (compared to mock-transfer stingrays) 24h after FW transfer. This pattern remained after two weeks in FW, with the exception that plasma corticosteroids returned to pre-acclimation levels. There were no significant differences between experimental groups in interrenal levels of mRNAs encoding key steroidogenic proteins (steroidogenic acute regulatory protein and cholesterol side chain cleavage enzyme). Temporally decreased corticosteroid levels during FW acclimation are consistent with the unique strategy of euryhaline elasmobranchs, whereby lower plasma osmolality is maintained in FW vs. SW environments to reduce hydromineral gradients.

  4. Light acclimation and pH perturbations affect photosynthetic performance in

    NARCIS (Netherlands)

    Ihnken, S.; Beardall, J.; Kromkamp, J.C.; Gómez Serrano, C.; Torres, M.A.; Masojídek, J.; Malpartida, I.; Abdala, R.; Gil Jerez, C.; Malapascua, J.R.; Navarro, E.; Rico, R.M.; Peralta, E.; Ferreira Ezequil, J.P.; Lopez Figueroa, F

    2014-01-01

    Chlorella spp. are robust chlorophyte microalgal species frequently used in mass culture. The pH optimum for growth is close to neutrality; at this pH, theoretically little energy is required to maintain homeostasis. In the present study, we grew Chlorella fusca cells in an open, outdoor, thin-layer

  5. Fall Chinook Acclimation Project; Pittsburg Landing, Captain John Rapids, and Big Canyon, Annual Report 2003.

    Energy Technology Data Exchange (ETDEWEB)

    McLeod, Bruce

    2004-01-01

    Fisheries co-managers of U.S. v Oregon supported and directed the construction and operation of acclimation and release facilities for Snake River fall Chinook from Lyons Ferry Hatchery at three sites above Lower Granite Dam. In 1996, Congress instructed the U.S. Army Corps of Engineers (USCOE) to construct, under the Lower Snake River Compensation Plan (LSRCP), final rearing and acclimation facilities for fall Chinook in the Snake River basin to complement their activities and efforts in compensating for fish lost due to construction of the lower Snake River dams. The Nez Perce Tribe (NPT) played a key role in securing funding and selecting acclimation sites, then assumed responsibility for operation and maintenance of the facilities. In 1997, Bonneville Power Administrative (BPA) was directed to fund operations and maintenance (O&M) for the facilities. Two acclimation facilities, Captain John Rapids and Pittsburg Landing, were located on the Snake River between Asotin, WA and Hells Canyon Dam and one facility, Big Canyon, was located on the Clearwater River at Peck. The Capt. John Rapids facility is a single pond while the Pittsburg Landing and Big Canyon sites consist of portable fish rearing tanks assembled and disassembled each year. Acclimation of 450,000 yearling smolts (150,000 each facility) begins in March and ends 6 weeks later. When available, an additional 2,400,000 fall Chinook sub-yearlings may be acclimated for 6 weeks, following the smolt release. The project goal is to increase the naturally spawning population of Snake River fall Chinook salmon upstream of Lower Granite Dam. This is a supplementation project; in that hatchery produced fish are acclimated and released into the natural spawning habitat for the purpose of returning a greater number of spawners to increase natural production. Only Snake River stock is used and production of juveniles occurs at Lyons Ferry Hatchery. This is a long-term project, targeted to work towards achieving

  6. Steady-state effects of temperature acclimation on the transcriptome of the rainbow trout heart.

    Science.gov (United States)

    Vornanen, Matti; Hassinen, Minna; Koskinen, Heikki; Krasnov, Aleksei

    2005-10-01

    Cold-acclimated (CA) phenotype of trout heart was induced by 4-wk acclimation at 4 degrees C and was characterized by 32.7% increase in relative heart mass and 49.8% increase in ventricular myocyte size compared with warm-acclimated (WA; 18 degrees C) fish (P temperature acclimation on transcriptome of the rainbow trout heart was examined using species-specific microarray chips containing 1,380 genes. After 4 wk of temperature acclimation, 8.8% (122) of the genes were differently expressed in CA and WA hearts, and most of them (82%) were upregulated in the cold (P collagen genes may be indicative of a reduced contribution of extracellular matrix to the remodeling of the CA fish heart. Temperature-related changes in transcripts of metabolic enzymes suggest that at mRNA level, glycolytic energy production from carbohydrates is compensated in the heart of CA rainbow trout, while metabolic compensation is absent in mitochondria. In addition, the analysis revealed three candidate genes: muscle LIM protein, atrial natriuretic peptide B, and myosin light chain 2, which might be central for induction and maintenance of the hypertrophic phenotype of the CA trout heart. These findings indicate that extensive modification of gene expression is needed to maintain the temperature-specific phenotype of the fish heart.

  7. Dynamic Acclimation to High Light in Arabidopsis thaliana Involves Widespread Reengineering of the Leaf Proteome

    Directory of Open Access Journals (Sweden)

    Matthew A. E. Miller

    2017-07-01

    Full Text Available Leaves of Arabidopsis thaliana transferred from low to high light increase their capacity for photosynthesis, a process of dynamic acclimation. A mutant, gpt2, lacking a chloroplast glucose-6-phosphate/phosphate translocator, is deficient in its ability to acclimate to increased light. Here, we have used a label-free proteomics approach, to perform relative quantitation of 1993 proteins from Arabidopsis wild type and gpt2 leaves exposed to increased light. Data are available via ProteomeXchange with identifier PXD006598. Acclimation to light is shown to involve increases in electron transport and carbon metabolism but no change in the abundance of photosynthetic reaction centers. The gpt2 mutant shows a similar increase in total protein content to wild type but differences in the extent of change of certain proteins, including in the relative abundance of the cytochrome b6f complex and plastocyanin, the thylakoid ATPase and selected Benson-Calvin cycle enzymes. Changes in leaf metabolite content as plants acclimate can be explained by changes in the abundance of enzymes involved in metabolism, which were reduced in gpt2 in some cases. Plants of gpt2 invest more in stress-related proteins, suggesting that their reduced ability to acclimate photosynthetic capacity results in increased stress.

  8. Role of CBFs as Integrators of Chloroplast Redox, Phytochrome and Plant Hormone Signaling during Cold Acclimation

    Directory of Open Access Journals (Sweden)

    Norman P. A. Hüner

    2013-06-01

    Full Text Available Cold acclimation of winter cereals and other winter hardy species is a prerequisite to increase subsequent freezing tolerance. Low temperatures upregulate the expression of C-repeat/dehydration-responsive element binding transcription factors (CBF/DREB1 which in turn induce the expression of COLD-REGULATED (COR genes. We summarize evidence which indicates that the integration of these interactions is responsible for the dwarf phenotype and enhanced photosynthetic performance associated with cold-acclimated and CBF-overexpressing plants. Plants overexpressing CBFs but grown at warm temperatures mimic the cold-tolerant, dwarf, compact phenotype; increased photosynthetic performance; and biomass accumulation typically associated with cold-acclimated plants. In this review, we propose a model whereby the cold acclimation signal is perceived by plants through an integration of low temperature and changes in light intensity, as well as changes in light quality. Such integration leads to the activation of the CBF-regulon and subsequent upregulation of COR gene and GA 2-oxidase (GA2ox expression which results in a dwarf phenotype coupled with increased freezing tolerance and enhanced photosynthetic performance. We conclude that, due to their photoautotrophic nature, plants do not rely on a single low temperature sensor, but integrate changes in light intensity, light quality, and membrane viscosity in order to establish the cold-acclimated state. CBFs appear to act as master regulators of these interconnecting sensing/signaling pathways.

  9. β-cyclocitral upregulates salicylic acid signalling to enhance excess light acclimation in Arabidopsis.

    Science.gov (United States)

    Lv, Feifei; Zhou, Jun; Zeng, Lizhang; Xing, Da

    2015-08-01

    β-cyclocitral (β-CC), a volatile oxidized derivative of β-carotene, can upregulate the expression of defence genes to enhance excess light (EL) acclimation. However, the signalling cascades underlying this process remain unclear. In this study, salicylic acid (SA) is involved in alleviating damage to promote β-CC-enhanced EL acclimation. In early stages of EL illumination, β-CC pretreatment induced SA accumulation and impeded reactive oxygen species (ROS) production in the chloroplast. A comparative analysis of two SA synthesis pathways in Arabidopsis revealed that SA concentration mainly increased via the isochorismate synthase 1 (ICS1)-mediated isochorismate pathway, which depended on essential regulative function of enhanced disease susceptibility 1 (EDS1). Further results showed that, in the process of β-CC-enhanced EL acclimation, nuclear localization of nonexpressor of pathogenesis-related genes 1 (NPR1) was regulated by SA accumulation and NPR1 induced subsequent transcriptional reprogramming of gluthathione-S-transferase 5 (GST5) and GST13 implicated in detoxification. In summary, β-CC-induced SA synthesis contributes to EL acclimation response by decreasing ROS production in the chloroplast, promoting nuclear localization of NPR1, and upregulating GST transcriptional expression. This process is a possible molecular regulative mechanism of β-CC-enhanced EL acclimation.

  10. Mathematical Modeling of Acclimation Processes of the Photosynthetic Chain

    Directory of Open Access Journals (Sweden)

    S Heidari

    2016-10-01

    Full Text Available Introduction Photosynthetic energy conversion efficiency is characteristic of a system which is determined by interactions between various components of the system. The complex process of photosynthesis has been studied as a whole system which enables in silico examination of a large number of candidate genes for genetic engineering for a higher photosynthetic energy conversion efficiency. One of the most important environmental factors which influence the photosynthesis efficiency is light regime which can cause producing ROS components. To acclimate to such fluctuations, plants have evolved adaptive mechanisms to minimize damage of the photosynthetic apparatus excess light. A fast compatibility response to high light stresses is non-photochemical quenching process (NPQ, dissipating excessive energy to heat. Light harvested state switches into a quenched state by a conformational change of light harvesting complex (LHCII that regulated by xanthophylls and the PsbS protein within seconds. Low lumen pH activates xanthophyll synthesis via a xanthophyll cycle which consists of the de-epoxidation of violaxanthin to zeaxanthin by violaxanthin de-epoxidase in high light and inversely by zeaxanthin epoxidase in low light which occurs more slowly. Materials and Methods Thale cress (Arabidopsis thaliana (Chlombia-0 were grown on soil at 25/22 °C day/night temperature, with a 16/8 h photoperiod, and 40-70% (depend of plant species relative humidity. The light intensity was 150–200 µE m-2s-1 white light. Intensity of chlorophyll fluorescence was measured with PAM-2000 fluorometer (Heinz Walz, Germany and the manufacturer’s software (PamWin v.2. Results and Discussion In the present study, a dynamic kinetics amplified mathematical model was developed based on differential equations in order to predict short-term changes in NPQ in the process of adaptation to different light conditions. We investigated the stationary and dynamic behavior of the model

  11. Partial heat acclimation of athletes with spinal cord lesion.

    Science.gov (United States)

    Castle, Paul C; Kularatne, B Pasan; Brewer, John; Mauger, Alexis R; Austen, Ross A; Tuttle, James A; Sculthorpe, Nick; Mackenzie, Richard W; Maxwell, Neil S; Webborn, Anthony D J

    2013-01-01

    Heat acclimation (HA) can improve thermoregulatory stability in able-bodied athletes in part by an enhanced sweat response. Athletes with spinal cord lesion are unable to sweat below the lesion and it is unknown if they can HA. Five paralympic shooting athletes with spinal cord lesion completed seven consecutive days HA in hot conditions (33.4 ± 0.6 °C, 64.8 ± 3.7 %rh). Each HA session consisted of 20 min arm crank exercise at 50 % [Formula: see text] followed by 40 min rest, or simulated shooting. Aural temperature (T (aur)) was recorded throughout. Body mass was assessed before and after each session and a sweat collection swab was fixed to T12 of the spine. Fingertip whole blood was sampled at rest on days 1 and 7 for estimation of the change in plasma volume. Resting T (aur) declined from 36.3 ± 0.2 °C on day 1 to 36.0 ± 0.2 °C by day 6 (P < 0.05). During the HA sessions mean, T (aur) declined from 37.2 ± 0.2 °C on day 1, to 36.7 ± 0.3 °C on day 7 (P < 0.05). Plasma volume increased from day 1 by 1.5 ± 0.6 % on day 7 (P < 0.05). No sweat secretion was detected or changes in body mass observed from any participant. Repeated hyperthermia combined with limited evaporative heat loss was sufficient to increase plasma volume, probably by alterations in fluid regulatory hormones. In conclusion, we found that although no sweat response was observed, athletes with spinal cord lesion could partially HA.

  12. Acclimating international graduate students to professional engineering ethics.

    Science.gov (United States)

    Newberry, Byron; Austin, Katherine; Lawson, William; Gorsuch, Greta; Darwin, Thomas

    2011-03-01

    This article describes the education portion of an ongoing grant-sponsored education and research project designed to help graduate students in all engineering disciplines learn about the basic ethical principles, rules, and obligations associated with engineering practice in the United States. While the curriculum developed for this project is used for both domestic and international students, the educational materials were designed to be sensitive to the specific needs of international graduate students. In recent years, engineering programs in the United States have sought to develop a larger role for professional ethics education in the curriculum. Accreditation requirements, as well as pressures from the private sector, have helped facilitate this shift in focus. Almost half of all engineering graduate students in the U.S. are international students. Further, research indicates that the majority of these students will remain in the U.S. to work post-graduation. It is therefore in the interest of the profession that these students, coming from diverse backgrounds, receive some formal exposure to the professional and ethical expectations and norms of the engineering profession in the United States to help ensure that they have the knowledge and skills--non-technical as well as technical--required in today's engineering profession. In becoming acculturated to professional norms in a host country, international students face challenges that domestic students do not encounter; such as cultural competency, language proficiency, and acculturation stress. Mitigating these challenges must be a consideration in the development of any effective education materials. The present article discusses the project rationale and describes the development of on-line instructional materials aimed at helping international engineering graduate students acclimate to professional engineering ethics standards in the United States. Finally, a brief data summary of students' perceptions

  13. Effectiveness of exercise-heat acclimation for preventing heat illness in the workplace.

    Science.gov (United States)

    Yamazaki, Fumio

    2013-09-01

    The incidence of heat-related illness in the workplace is linked to whether or not workers have acclimated to a hot environment. Heat acclimation improves endurance work performance in the heat and thermal comfort at a given work rate. These improvements are achieved by increased sweating and skin blood flow responses, better fluid balance and cardiovascular stability. As a practical means of acclimatizing the body to heat stress, daily aerobic exercise training is recommended since thermoregulatory capacity and blood volume increase with physical fitness. In workers wearing personal protective suits in hot environments, however, little psychophysiological benefit is received from short-term exercise training and/or heat acclimation because of the ineffectiveness of sweating for heat dissipation and the aggravation of thermal discomfort with the accumulation of sweat within the suit. For a manual laborer who works under uncompensable heat stress, better management of the work rate, the work environment and health is required.

  14. An integrated analysis of molecular acclimation to high light in the marine diatom Phaeodactylum tricornutum

    DEFF Research Database (Denmark)

    Nymark, Marianne; Valle, Kristin C; Brembu, Tore

    2009-01-01

    Photosynthetic diatoms are exposed to rapid and unpredictable changes in irradiance and spectral quality, and must be able to acclimate their light harvesting systems to varying light conditions. Molecular mechanisms behind light acclimation in diatoms are largely unknown. We set out to investigate...... phase (3-12 h) and a late acclimation phase (12-48 h). The initial phase is recognized by strong and rapid regulation of genes encoding proteins involved in photosynthesis, pigment metabolism and reactive oxygen species (ROS) scavenging systems. A significant increase in light protecting metabolites...... occur together with the induction of transcriptional processes involved in protection of cellular structures at this early phase. During the following phases, the metabolite profiling display a pronounced decrease in light harvesting pigments, whereas the variable fluorescence measurements show...

  15. Acclimation to extremely high ammonia levels in continuous biomethanation process and the associated microbial community dynamics

    DEFF Research Database (Denmark)

    Tian, Hailin; Fotidis, Ioannis; Mancini, Enrico

    2017-01-01

    Acclimatized anaerobic communities to high ammonia levels can offer a solution to the ammonia toxicity problem in biogas reactors. In the current study, a stepwise acclimation strategy up to 10 g NH4+-N L−1, was performed in mesophilic (37 ± 1 °C) continuously stirred tank reactors. The reactors...... were co-digesting (20/80 based on volatile solid) cattle slurry and microalgae, a protein-rich, 3rd generation biomass. Throughout the acclimation period, methane production was stable with more than 95% of the uninhibited yield. Next generation 16S rRNA gene sequencing revealed a dramatic microbiome...... change throughout the ammonia acclimation process. Clostridium ultunense, a syntrophic acetate oxidizing bacteria, increased significantly alongside with hydrogenotrophic methanogen Methanoculleus spp., indicating strong hydrogenotrophic methanogenic activity at extreme ammonia levels (>7 g NH4+-N L−1...

  16. Costs and benefits of cold acclimation in field released Drosophila – Associating laboratory and field results.

    DEFF Research Database (Denmark)

    Overgaard, Johannes; Sørensen, Jesper Givskov; A. Hoffmann, Ary

    2008-01-01

    Physiological and evolutionary responses to thermal variation are often investigated under controlled laboratory conditions. However, this approach may fail to account for the complexity of natural environments. Here we investigated the costs and benefits of developmental or adult cold acclimation...... temperatures where cold acclimated flies were up to 36 times less likely to find a resource under warm conditions. These costs were not detected in standard laboratory tests but indicate that physiological acclimation may improve fitness only over a narrow set of thermal conditions while it may have...... that the ability to locate a field resource has a genetic basis with a high heritability since only round of selection on parental flies (F0) revealed clear differences in the ability of offspring (F1 and F2) to locate field resources at cold temperatures. Again we found a poor association between field...

  17. Acclimation of tree function and structure to climate change and implications to forest carbon and nutrient balances

    Energy Technology Data Exchange (ETDEWEB)

    Hari, P.; Nissinen, A.; Berninger, F. [Helsinki Univ. (Finland). Dept. of Forest Ecology] [and others

    1996-12-31

    Before large-scale anthropogenetic emissions the environmental factors have been rather stable for thousands of years, varying yearly, seasonally and daily in rather regular manners around some mean values. In this century the emissions of CO{sub 2}, sulphur and nitrogen from society to atmosphere are changing both atmospheric and soil environment at rates not experienced before. The fluxes to soil affect the contents of plant available nutrients and solubility of toxic compounds in the forest soil. Additionally, the chemical state of soil environment is coupled to tree growth, litter production and nutrient uptake as well as to the activity of biological organisms in soil, which decompose litter and release nutrients from it. Trees have developed effective regulation systems to cope with the environment during the evolution. The resulting acclimations improve the functioning of the trees if the environmental factors remain within their range of variation during the evolution. Outside the range the results of the regulation are unpredictable. The acclimative changes caused by the action of the regulation system may considerably change the response of trees to present environmental change. The analysis of the effects of present environmental change on forests requires simultaneous treatment of the atmosphere, forest soils and trees. Each of these components is dominated by its own features. The analyze of material and energy fluxes connect them to each other. The aim of this research is to analyse changes in the forest soils and reactions of trees to changes in the atmosphere and forest soils under a common theoretical framework, enabling combination of the obtained results into a holistic analysis of the response of forests to the present environmental change

  18. Sensitivity of Scenedesmus obliquus and Microcystis aeruginosa to atrazine: effects of acclimation and mixed cultures, and their removal ability.

    Science.gov (United States)

    Chalifour, Annie; LeBlanc, André; Sleno, Lekha; Juneau, Philippe

    2016-12-01

    Atrazine is an herbicide frequently detected in watercourses that can affect the phytoplankton community, thus impacting the whole food chain. This study aims, firstly, to measure the sensitivity of monocultures of the green alga Scenedemus obliquus and toxic and non-toxic strains of the cyanobacteria Microcystis aeruginosa before, during and after a 30-day acclimation period to 0.1 µM of atrazine. Secondly, the sensitivity of S. obliquus and M. aeruginosa to atrazine in mixed cultures was evaluated. Finally, the ability of these strains to remove atrazine from the media was measured. We demonstrated that both strains of M. aeruginosa had higher growth rate-based EC50 values than S. obliquus when exposed to atrazine, even though their photosynthesis-based EC50 values were lower. After being exposed to 0.1 µM of atrazine for 1 month, only the photosynthesis-based EC50 of S. obliquus increased significantly. In mixed cultures, the growth rate of the non-toxic strain of M. aeruginosa was higher than S. obliquus at high concentrations of atrazine, resulting in a ratio of M. aeruginosa to total cell count of 0.6. This lower sensitivity might be related to the higher growth rate of cyanobacteria at low light intensity. Finally, a negligible fraction of atrazine was removed from the culture media by S. obliquus or M. aeruginosa over 6 days. These results bring new insights on the acclimation of some phytoplankton species to atrazine and its effect on the competition between S. obliquus and M. aeruginosa in mixed cultures.

  19. Effect of operational strategies on activated sludge’s acclimation to phenol, subsequent aerobic granulation, and accumulation of polyhydoxyalkanoates

    Energy Technology Data Exchange (ETDEWEB)

    Wosman, Afrida; Lu, Yuhao; Sun, Supu; Liu, Xiang [Department of Environmental Science and Engineering, Fudan University, 220 Handan Road, Yangpu District, Shanghai, 200433 (China); Wan, Chunli, E-mail: hitwan@163.com [Department of Environmental Science and Engineering, Fudan University, 220 Handan Road, Yangpu District, Shanghai, 200433 (China); Zhang, Yi, E-mail: sybil_zhang@yahoo.com [Department of Environmental Science and Engineering, Fudan University, 220 Handan Road, Yangpu District, Shanghai, 200433 (China); Lee, Duu-Jong [Department of Chemical Engineering, National Taiwan University of Science and Technology, Taipei 106, Taiwan (China); Tay, JooHwa [Department of Civil Engineering, University of Calgary, Calgary, AB T2N 1N4 (Canada)

    2016-11-05

    Highlights: • Activated sludge was acclimated to phenol with 2 different strategies. • Acclimated sludge later underwent aerobic granulation process. • Sludge acclimated with phenol only degraded phenol and formed granules faster. • Sludge acclimated with phenol + acetate formed more stable and robust granules. • Both sludge exhibited significant PHA accumulation in early granulation stage. - Abstract: Aerobic granules, a relative novel form of microbial aggregate, are capable of degrading many toxic organic pollutants. Appropriate strategy is needed to acclimate seed sludge to the toxic compounds for successful granulation. In this study, two distinct strategies, i.e. mixed or single carbon sources, were experimented to obtain phenol-acclimated sludge. Their effects on reactor performance, biomass characteristics, microbial population and the granulation process were analyzed. Sludge fed with phenol alone exhibited faster acclimation and earlier appearance of granules, but possibly lower microbial diversity and reactor stability. Using a mixture of acetate and phenol in the acclimation stage, on the other hand, led to a reactor with slower phenol degradation and granulation, but eventual formation of strong and stable aerobic granules. In addition, the content of intracellular polyhydoxyakanoates (PHA) was also monitored, and significant accumulation was observed during the pre-granulation stage, where PHA >50% of dry weight was observed in both reactors.

  20. [Study on biodegradation of 2,4-DCP by anaerobic sludge acclimated by mixed mono-chlorphenols].

    Science.gov (United States)

    Zhang, Wen; Chen, Ling; Ji, Jun-Ping; Xia, Si-Qing

    2007-06-01

    Purpose of this study was to determine the treatability of 2,4-dichlorophenol (2,4-DCP) by anaerobic granular sludge which was acclimated by mixed mono-chlorphenols (2-CP, 4-MCP). The characteristic of degradation of 2,4-DCP by anaerobic sludge acclimated by mixed mono-chlorphenols was investigated through shake flask study and performance of continuous flow anaerobic bioreactors. The difference of degradation of 2,4-DCP by acclimated and unacclimated sludge was also compared. 2,4-DCP was degraded at 50 h and 180 h respectively for acclimated and unacclimated sludge, which testified that acclimated sludge could more effectively degrade 2,4-DCP. Although the intermediate product 4-MCP was present in both reaction system, 4-MCP could be degraded completely after 400 h in the acclimated sludge but accumulated in the unacclimated sludge. Therefore, acclimation by the mixed mono-chlorphenols (2-CP, 4-MCP) could enhance the ability of para- and meta-dechlorination for anaerobic sludge and increase the treatability of 2,4-DCP. The results of continuous anaerobic sludge-suspended carrier bioreactor (ASSCB) indicate that inoculation of the acclimated sludge by mixed mono-chlorphenols can degrade two mono-chlorphenols simultaneously, shorten the setup period, and increase the efficiency of degrading 2,4-DCP. 2-CP was easily degraded with removal rate of over 80% . While the removal rate of 4-MCP was fluctuating within 30% - 80% with changes of its influent concentration.

  1. General patterns of acclimation of leaf respiration to elevated temperatures across biomes and plant types.

    Science.gov (United States)

    Slot, Martijn; Kitajima, Kaoru

    2015-03-01

    Respiration is instrumental for survival and growth of plants, but increasing costs of maintenance processes with warming have the potential to change the balance between photosynthetic carbon uptake and respiratory carbon release from leaves. Climate warming may cause substantial increases of leaf respiratory carbon fluxes, which would further impact the carbon balance of terrestrial vegetation. However, downregulation of respiratory physiology via thermal acclimation may mitigate this impact. We have conducted a meta-analysis with data collected from 43 independent studies to assess quantitatively the thermal acclimation capacity of leaf dark respiration to warming of terrestrial plant species from across the globe. In total, 282 temperature contrasts were included in the meta-analysis, representing 103 species of forbs, graminoids, shrubs, trees and lianas native to arctic, boreal, temperate and tropical ecosystems. Acclimation to warming was found to decrease respiration at a set temperature in the majority of the observations, regardless of the biome of origin and growth form, but respiration was not completely homeostatic across temperatures in the majority of cases. Leaves that developed at a new temperature had a greater capacity for acclimation than those transferred to a new temperature. We conclude that leaf respiration of most terrestrial plants can acclimate to gradual warming, potentially reducing the magnitude of the positive feedback between climate and the carbon cycle in a warming world. More empirical data are, however, needed to improve our understanding of interspecific variation in thermal acclimation capacity, and to better predict patterns in respiratory carbon fluxes both within and across biomes in the face of ongoing global warming.

  2. Effect of pre-acclimation of granular activated carbon on microbial electrolysis cell startup and performance

    KAUST Repository

    LaBarge, Nicole

    2016-09-09

    Microbial electrolysis cells (MECs) can generate methane by fixing carbon dioxide without using expensive catalysts, but the impact of acclimation procedures on subsequent performance has not been investigated. Granular activated carbon (GAC) was used to pre-enrich electrotrophic methanogenic communities, as GAC has been shown to stimulate direct transfer of electrons between different microbial species. MEC startup times using pre-acclimated GAC were improved compared to controls (without pre-acclimation or without GAC), and after three fed batch cycles methane generation rates were similar (P > 0.4) for GAC acclimated to hydrogen (22 ± 9.3 nmol cm− 3 d− 1), methanol (25 ± 9.7 nmol cm− 3 d− 1), and a volatile fatty acid (VFA) mix (22 ± 11 nmol cm− 3 d− 1). However, MECs started with GAC but no pre-acclimation had lower methane generation rates (13 ± 4.1 nmol cm− 3 d− 1), and MECs without GAC had the lowest rates (0.7 ± 0.8 nmol cm− 3 d− 1 after cycle 2). Microbes previously found in methanogenic MECs, or previously shown to be capable of exocellular electron transfer, were enriched on the GAC. Pre-acclimation using GAC is therefore a simple approach to enrich electroactive communities, improve methane generation rates, and decrease startup times in MECs. © 2016 Elsevier B.V.

  3. The role of antioxidant system in freezing acclimation-induced freezing resistance of Populus suaveolens cuttings

    Institute of Scientific and Technical Information of China (English)

    Luo Lei; Lin Shan-zhi; Zheng Hui-quan; Lei Yang; Zhang Qian; Zhang Zhi-yi

    2007-01-01

    We investigated the changes in the contents of H2O2, malonaldehyde (MDA) and endogenous antioxidants, the activities of protective enzymes and some critical enzymes involved in the ascorbate-glutathione (ASA-GSH) cycle as well as freezing resistance(expressed as LT50) and correlations mentioned above, in detail using Populus suaveolens cuttings. The purpose was to explore the physiological mechanism of the enhancement of freezing resistance induced by freezing acclimation at -20℃, and to elucidate the physiological mechanisms by which trees adapt to freezing. The results showed that freezing acclimation enhanced the activities of superoxide dismutase (SOD), peroxidase (POD), catalase (CAT), monodehydroascorbate reductase (MDAR), ascorbate peroxidase(APX), dehydroascorbate reductase (DHAR) and glutathione reductase (GR). And it increased the contents of reduced ascorbate(ASA), reduced glutathione (GSH), dehydroascorbate (DHA) and oxidized glutathione (GSSG). However, H2O2 and MDA contents and LT50 of cuttings were decreased. LT50 in cuttings was found to be closely correlated to the levels of SOD, POD, CAT, APX,DHAR, MDAR, GR, H2O2, MDA, ASA, GSH, DHA and GSSG during freezing acclimation. This suggested that the enhancement of freezing resistance of cuttings induced by freezing acclimation may relate to the distinct increase for the levels of SOD, POD, CAT,APX, DHAR, MDAR,GR,ASA, GSH, DHA, and GSSG. In addition, the observed levels of APX, DHAR, MDAR, GR, ASA, DHA,GSH and GSSG were higher than those of SOD, POD and CAT during freezing acclimation. It indicated that a higher capacity of the ASA-GSH cycle is required for H2O2 detoxification, and growth and development of cuttings. Based on the obtained results, it can be concluded that the ASA-GSH cycle plays an important role in enhancement of freezing resistance of P. suaveolens cuttings during freezing acclimation.

  4. Seasonal acclimation in metabolism reduces light requirements of eelgrass (Zostera marina)

    DEFF Research Database (Denmark)

    Stæhr, Peter A.; Borum, Jens

    2011-01-01

    We investigated the ability of eelgrass (Zostera marina) to adjust light requirements to seasonal changes in temperature, light and nutrient conditions through changes in metabolism, pigment and nutrient content. In agreement with expectations we found that rates of respiration and light saturated...... photosynthesis of summer acclimated plants peaked at higher temperatures (5 °C and 2 °C higher, respectively), and were lower than of winter acclimated plants, both at sub- and supra-optimal temperatures. Moreover respiration rates were generally more sensitive to increasing temperatures than photosynthetic...

  5. IGF-I and branchial IGF receptor expression and localization during salinity acclimation in striped bass

    DEFF Research Database (Denmark)

    Tipsmark, Christian Kølbaek; Luckenbach, John Adam; Madsen, Steffen

    2007-01-01

    The initial response of the IGF-I system and the expression and cellular localization of IGF type-I receptor (IGF-IR) were studied in the gill of a euryhaline teleost during salinity acclimation. Exposure of striped bass (Morone saxatilis) to hyperosmotic and hypoosmotic challenges induced small...... in either plasma IGF-I, liver, or gill IGF-I mRNA, or gill IGF-IR mRNA levels. In a separate experiment, FW-acclimated fish were injected with saline or IGF-I prior to a 24-h SW challenge. Rapid regain of osmotic balance following SW transfer was hindered by IGF-I. Immunohistochemistry revealed...

  6. Acclimation of a terrestrial plant to submergence facilitates gas exchange under water

    DEFF Research Database (Denmark)

    Mommer, L.; Pedersen, O.; Visser, E. J. W.

    2004-01-01

    . The present study demonstrates that the internal oxygen pressure in the petioles of Rumex palustris plants under water is indeed well above the critical oxygen pressure for aerobic respiration, provided that the air-saturated water is not completely stagnant. The beneficial effect of shoot acclimation...... of this terrestrial plant species to submergence for gas exchange capacity is also shown. Shoot acclimation to submergence involved a reduction of the diffusion resistance to gases, which was not only functional by increasing diffusion of oxygen into the plant, but also by increasing influx of CO2, which enhances...

  7. Sensitivity of cold acclimation to elevated autumn temperature in field-grown Pinus strobus seedlings

    Directory of Open Access Journals (Sweden)

    Christine Yao-Yun Chang

    2015-03-01

    Full Text Available Climate change will increase autumn air temperature, while photoperiod decrease will remain unaffected. We assessed the effect of increased autumn air temperature on timing and development of cold acclimation and freezing resistance in Eastern white pine (EWP, Pinus strobus under field conditions. For this purpose we simulated projected warmer temperatures for southern Ontario in a Temperature Free-Air-Controlled Enhancement (T-FACE experiment and exposed EWP seedlings to ambient (Control or elevated temperature (ET, +1.5°C/+3°C during day/night. Photosynthetic gas exchange, chlorophyll fluorescence, photoprotective pigments, leaf non-structural carbohydrates (NSC, and cold hardiness were assessed over two consecutive autumns. Nighttime temperature below 10°C and photoperiod below 12h initiated downregulation of assimilation in both treatments. When temperature further decreased to 0°C and photoperiod became shorter than 10h, downregulation of the light reactions and upregulation of photoprotective mechanisms occurred in both treatments. While ET seedlings did not delay the timing of the downregulation of assimilation, stomatal conductance in ET seedlings was decreased by 20-30% between August and early October. In both treatments leaf NSC composition changed considerably during autumn but differences between Control and ET seedlings were not significant. Similarly, development of freezing resistance was induced by exposure to low temperature during autumn, but the timing was not delayed in ET seedlings compared to Control seedlings. Our results indicate that EWP is most sensitive to temperature changes during October and November when downregulation of photosynthesis , enhancement of photoprotection, synthesis of cold-associated NSCs and development of freezing resistance occur. However, we also conclude that the timing of the development of freezing resistance in EWP seedlings is not affected by moderate temperature increases used in our

  8. Synechococcus sp. strain PCC 7002 transcriptome: acclimation to temperature, salinity, oxidative stress and mixotrophic growth conditions

    Directory of Open Access Journals (Sweden)

    Marcus eLudwig

    2012-10-01

    Full Text Available Synechococcus sp. strain PCC 7002 is a unicellular, euryhaline cyanobacterium. It is a model organism for studies of cyanobacterial metabolism and has great potential for biotechnological applications. It exhibits an exceptional tolerance of high light irradiation and shows very rapid growth. The habitats from which this and closely related strains were isolated are subject to changes in several environmental factors, including light, nutrient supply, temperature, and salinity. In this study global transcriptome profiling via RNAseq has been used to perform a comparative and integrated study of global changes in cells grown at different temperatures, at different salinities and under mixotrophic conditions, when a metabolizable organic carbon source was present. Furthermore, the transcriptomes were investigated for cells that were subjected to a heat shock and that were exposed to oxidative stress. Lower growth temperatures caused relatively minor changes of the transcriptome; the most prominent changes affected fatty acid desaturases. A heat shock caused severe changes of the transcriptome pattern; transcripts for genes associated with major metabolic pathways declined and those for different chaperones increased dramatically. Oxidative stress, however, left the transcript pattern almost unaffected. When grown at high salinity, Synechococcus sp. PCC 7002 had increased expression of genes involved in compatible solute biosynthesis and showed increased mRNA levels for several genes involved in electron transport. Transcripts of two adjacent genes dramatically increased upon growth at high salinity; the respective proteins are putatively involved in coping with oxidative stress and in triggering ion channels. Only minor changes were observed when cells were grown at low salinity or when the growth medium was supplemented with glycerol. However, the transcriptome data suggest that cells must acclimate to excess reducing equivalents when a reduced C

  9. Liver transcriptome changes in zebrafish during acclimation to transport-associated stress.

    Directory of Open Access Journals (Sweden)

    Anusha K S Dhanasiri

    Full Text Available Liver plays a key role during the stress acclimation, and liver transcriptome analysis of shipped zebrafish could reveal the molecular adjustments that occur in the organ. Transcriptional changes in liver were analyzed with a 44 K oligo array using total RNA from fish prior to transport and during a mock transport process--immediately after packing (0 h, at 48 and 72 h. Large numbers of genes related to a variety of biological processes and pathways were regulated, mainly during transport (at 48/72 h. Immediately after packing, transcripts of genes related to both gluconeogenesis and glycolysis were induced. During transport, induction of gluconeogenesis-linked genes and reduction of glycolysis-related genes may be supporting the increase in blood glucose levels. Inhibition of genes involved in fatty acid beta-oxidation may be pointing to the poor ability of fish to utilize energy from fatty acids, under transport conditions. Genes involved in some of the mechanisms that regulate body ammonia were also affected. Even though genes associated with certain transaminases were inhibited in liver, sustained glutamate deamination may have led to high ammonia accumulation in liver/body. Enhanced levels of gene transcripts in ubiquitination and MAPK signalling cascade and reduced levels of gene transcripts related to ROS generation via peroxisomal enzymes as well as xenobiotic metabolism may be signifying the importance of such cellular and tissue responses to maintain homeostasis. Furthermore, transcripts connected with stress and thyroid hormones were also regulated. Moreover, suppression of genes related to specific immune components may be denoting the deleterious impact of transport on fish health. Thus, this study has revealed the complex molecular adjustments that occur in zebrafish when they are transported.

  10. Unsaturated Lipids Change in Olive Tree Drupe and Seed during Fruit Development and in Response to Cold-Stress and Acclimation

    Directory of Open Access Journals (Sweden)

    Simone D’Angeli

    2016-11-01

    Full Text Available The olive tree is a plant of economic value for the oil of its drupe. It is a cultigen complex composed of genotypes with differences in cold-hardiness. About 90% of the oil is stored in oil bodies (OBs in the drupe during the oleogenic phase. Phenols and lipids contribute to oil quality, but the unsaturated fatty acid (FA fraction is emerging as the most important for quality, because of the very high content in oleic acid, the presence of ω6-linoleic acid and ω3-linolenic acid, and the very low saturated FA content. Another 10% of oil is produced by the seed. Differences in unsaturated FA-enriched lipids exist among seed coat, endosperm, and embryo. Olive oil quality is also affected by the environmental conditions during fruit growth and genotype peculiarities. Production of linoleic and α-linolenic acids, fruit growth, fruit and leaf responses to low temperatures, including cuticle formation, and cold-acclimation are related processes. The levels of unsaturated FAs are changed by FA-desaturase (FAD activities, involving the functioning of chloroplasts and endoplasmic reticulum. Cold induces lipid changes during drupe and seed development, affecting FADs, but its effect is related to the genotype capability to acclimate to the cold.

  11. Unsaturated Lipids Change in Olive Tree Drupe and Seed during Fruit Development and in Response to Cold-Stress and Acclimation.

    Science.gov (United States)

    D'Angeli, Simone; Altamura, Maria Maddalena

    2016-11-12

    The olive tree is a plant of economic value for the oil of its drupe. It is a cultigen complex composed of genotypes with differences in cold-hardiness. About 90% of the oil is stored in oil bodies (OBs) in the drupe during the oleogenic phase. Phenols and lipids contribute to oil quality, but the unsaturated fatty acid (FA) fraction is emerging as the most important for quality, because of the very high content in oleic acid, the presence of ω6-linoleic acid and ω3-linolenic acid, and the very low saturated FA content. Another 10% of oil is produced by the seed. Differences in unsaturated FA-enriched lipids exist among seed coat, endosperm, and embryo. Olive oil quality is also affected by the environmental conditions during fruit growth and genotype peculiarities. Production of linoleic and α-linolenic acids, fruit growth, fruit and leaf responses to low temperatures, including cuticle formation, and cold-acclimation are related processes. The levels of unsaturated FAs are changed by FA-desaturase (FAD) activities, involving the functioning of chloroplasts and endoplasmic reticulum. Cold induces lipid changes during drupe and seed development, affecting FADs, but its effect is related to the genotype capability to acclimate to the cold.

  12. Thermal fluctuations affect the transcriptome through mechanisms independent of average temperature.

    Science.gov (United States)

    Sørensen, Jesper Givskov; Schou, Mads Fristrup; Kristensen, Torsten Nygaard; Loeschcke, Volker

    2016-08-04

    Terrestrial ectotherms are challenged by variation in both mean and variance of temperature. Phenotypic plasticity (thermal acclimation) might mitigate adverse effects, however, we lack a fundamental understanding of the molecular mechanisms of thermal acclimation and how they are affected by fluctuating temperature. Here we investigated the effect of thermal acclimation in Drosophila melanogaster on critical thermal maxima (CTmax) and associated global gene expression profiles as induced by two constant and two ecologically relevant (non-stressful) diurnally fluctuating temperature regimes. Both mean and fluctuation of temperature contributed to thermal acclimation and affected the transcriptome. The transcriptomic response to mean temperatures comprised modification of a major part of the transcriptome, while the response to fluctuations affected a much smaller set of genes, which was highly independent of both the response to a change in mean temperature and to the classic heat shock response. Although the independent transcriptional effects caused by fluctuations were relatively small, they are likely to contribute to our understanding of thermal adaptation. We provide evidence that environmental sensing, particularly phototransduction, is a central mechanism underlying the regulation of thermal acclimation to fluctuating temperatures. Thus, genes and pathways involved in phototransduction are likely of importance in fluctuating climates.

  13. The temperature response of CO2 assimilation, photochemical activities and Rubisco activation in Camelina sativa, a potential bioenergy crop with limited capacity for acclimation to heat stress.

    Science.gov (United States)

    Carmo-Silva, A Elizabete; Salvucci, Michael E

    2012-11-01

    The temperature optimum of photosynthesis coincides with the average daytime temperature in a species' native environment. Moderate heat stress occurs when temperatures exceed the optimum, inhibiting photosynthesis and decreasing productivity. In the present study, the temperature response of photosynthesis and the potential for heat acclimation was evaluated for Camelina sativa, a bioenergy crop. The temperature optimum of net CO(2) assimilation rate (A) under atmospheric conditions was 30-32 °C and was only slightly higher under non-photorespiratory conditions. The activation state of Rubisco was closely correlated with A at supra-optimal temperatures, exhibiting a parallel decrease with increasing leaf temperature. At both control and elevated temperatures, the modeled response of A to intercellular CO(2) concentration was consistent with Rubisco limiting A at ambient CO(2). Rubisco activation and photochemical activities were affected by moderate heat stress at lower temperatures in camelina than in the warm-adapted species cotton and tobacco. Growth under conditions that imposed a daily interval of moderate heat stress caused a 63 % reduction in camelina seed yield. Levels of cpn60 protein were elevated under the higher growth temperature, but acclimation of photosynthesis was minimal. Inactivation of Rubisco in camelina at temperatures above 35 °C was consistent with the temperature response of Rubisco activase activity and indicated that Rubisco activase was a prime target of inhibition by moderate heat stress in camelina. That photosynthesis exhibited no acclimation to moderate heat stress will likely impact the development of camelina and other cool season Brassicaceae as sources of bioenergy in a warmer world.

  14. Antioxidative responses of two marine microalgae during acclimation to static and fluctuating natural UV radiation

    NARCIS (Netherlands)

    Janknegt, Paul J.; de Graaff, C. Marco; van de Poll, Willem H.; Visser, Ronald J. W.; Walter Helbling, E.; Buma, Anita G. J.

    2009-01-01

    Photoacclimation properties were investigated in two marine microalgae exposed to four ambient irradiance conditions: static photosynthetically active radiation (PAR: 400-700 nm), static PAR + UVR (280-700 nm), dynamic PAR and dynamic PAR + UVR. High light acclimated cultures of Thalassiosira weissf

  15. Light acclimation strategies change from summer green to spring ephemeral as wild-leek plants age.

    Science.gov (United States)

    Dion, Pierre-Paul; Brisson, Jacques; Fontaine, Bastien; Lapointe, Line

    2016-05-01

    Spring-ephemeral forest-herbs emerge early to take advantage of the high-light conditions preceding canopy closure; they complete their life cycle in a few weeks, then senesce as the tree canopy closes. Summer greens acclimate their leaves to shade and thus manage to maintain a net carbon gain throughout summer. Differences in phenology among life stages within a species have been reported in tree saplings, whose leaf activity may extend beyond the period of shade conditions caused by mature trees. Similar phenological acclimation has seldom been studied in forest herbs. We compared wild-leek bulb growth and leaf phenology among plants from seedling to maturity and from under 4 to 60% natural light availability. We also compared leaf chlorophyll content and chl a/b ratio among seedlings and adult plants in a natural population as an indicator of photosynthetic capacity and acclimation to light environment. Overall, younger plants senesced later than mature ones. Increasing light availability delayed senescence in mature plants, while hastening seedling senescence. In natural populations, only seedlings acclimated to the natural reduction in light availability through time. Wild-leek seedlings exhibit a summer-green phenology, whereas mature plants behave as true spring ephemerals. Growth appears to be more source-limited in seedlings than in mature plants. This modulation of phenological strategy, if confirmed in other species, would require a review of the current classification of species as either spring ephemerals, summer greens, wintergreens, or evergreens. © 2016 Botanical Society of America.

  16. Effect of acclimation temperature and pH on contraction of frog sartorius muscle.

    Science.gov (United States)

    Renaud, J M; Stevens, E D

    1981-05-01

    The effect of acclimation temperature and pH on the isometric twitch and tetanus of sartorius muscle from frog, Rana pipiens, was studied at different experimental temperatures. Seven variables were measured, namely: tension, latent period, time to maximum tension, half-relaxation time, mean rate, maximum rate, and maximum acceleration of tension development. The effect of experimental temperature was similar to that reported in the literature. The effects of acclimation temperature were small and were not compensatory. Different pH's were obtained by varying CO2 in the gas phase, while the HCO3- concentration was kept constant. The main effects of a decrease in pH on the isometric twitch and tetanus were a reduction in tension and rate of tension development and an increase in latent period. A decrease in pH had no effect on the time to maximum tension or the half-relaxation time. Analysis of variance showed that the test temperature had the greatest effect of all three treatments on each variable, the effects of test and acclimation temperature were dependent on neither the test nor the acclimation temperatures. The in vivo relationships between these three treatments are discussed.

  17. Trait Acclimation Mitigates Mortality Risks of Tropical Canopy Trees under Global Warming

    NARCIS (Netherlands)

    Sterck, Frank; Anten, Niels P.R.; Schieving, Feike; Zuidema, Pieter A.

    2016-01-01

    There is a heated debate about the effect of global change on tropical forests. Many scientists predict large-scale tree mortality while others point to mitigating roles of CO2 fertilization and – the notoriously unknown – physiological trait acclimation of trees. In this opinion article we provided

  18. Consequences of acclimation to Microcystis on the selective feeding behavior of the calanoid copepod Eudiaptomus gracilis

    NARCIS (Netherlands)

    Ger, K.A.; Panosso, R.; Lürling, M.F.L.L.W.

    2011-01-01

    We tested the hypothesis that calanoid copepods would adapt to extended periods of Microcystis exposure by increasing selective feeding on alternative food. Copepod (Eudiaptomus gracilis) clearance rates were compared before and after a 5-d acclimation to Microcystis aeruginosa using paired food mix

  19. Winter wheat morphology response to cold temperature stress during autumn acclimation

    Directory of Open Access Journals (Sweden)

    Ligita Baležentienė

    2012-03-01

    Full Text Available Winter wheat (Triticum aestivum L. abilities depend on development during autumn acclimation. The plant ability of acclimation to low temperatures is closely associated with the photosynthesis level, leaf area index (LAI, root system development. This study investigated the effect of liquid humic fertilizers (LHF on biometric characteristics, namely LAI, root and shoot development. The fertilizers were applied in conventional and organic growth technologies of w. wheat to adapt to the low temperatures during autumn acclimation. Winter wheat «Širvinta 1 » was grown in different rotation fields of conventional (CF; Albi-EpihypogleyicLuvisol, LVg-p-w-ab and organic (OF; Hapli-EpihypogleyicLuvisol, LVg-p-w-ha farming of Training Farm at Aleksandras Stulginskis University (ASU during 2010–2011. The obtained results confirmed the significant LHF influence on enhancing winter wheat biometrical indices and seedling growth. Nonetheless, seed felting exhibited stronger effect on LAI (increased by 0.7-1.1 g m -1 day -1 in OF and 0.25-0.7 g m -1 day -1 in CF, root length (increased by 1166 mm in OF and 1182.55 mm in CF and area (increased by 72.45 mm 2 in OF and 588.7 mm 2 in CF during autumn acclimation rather than seedling spraying.

  20. Sugar-Mediated Acclimation: The Importance of Sucrose Metabolism in Meristems

    NARCIS (Netherlands)

    Carpentier, S.C.; Vertommen, A.; Swennen, R.; Witters, E.; Fortes, C.; Souza, M.T.; Panis, B.

    2010-01-01

    We have designed an in vitro experimental setup to study the role of sucrose in sugar-mediated acclimation of banana meristems using established highly proliferating meristem cultures. It is a first step toward the systems biology of a meristem and the understanding of how it can survive severe

  1. Oxygen Consumption and Swimming Performance in Hypoxia-Acclimated Rainbow Trout Salmo Gairdneri

    DEFF Research Database (Denmark)

    BUSHNELL, PG; STEFFENSEN, JF; JOHANSEN, K

    1984-01-01

    1. Swimming performance and oxygen consumption of normoxic (control) and hypoxia-acclimated (P002=40 mmHg) rainbow trout, Salmo gairdneri Richardson, were monitored at >145, 60 and 40mmHg. 2. Maximum swimming velocity at 40mmHg was reduced from >54.8cm s-1 to 41.4cm s1 in controls and to 40.6 cm s......Hg did not significantly change oxygen consumption in control animals, although no fish (control or hypoxia acclimated) completed swimming trials at 54.8cm s-1 in 40mmHg. 5. Oxygen consumption of hypoxia-acclimated fish at 5.5cm s-1 and 40 mmHg was significantly higher than oxygen uptake in normoxia...... at the same speed. This relative increase was not maintained, however, as oxygen consumption at higher swimming speeds was similar to that in normoxia. 6. Blood studies showed that hypoxia-acclimated fish had lower ATP concentrations and P50 values. While these factors may increase the blood oxygen loading...

  2. Trait Acclimation Mitigates Mortality Risks of Tropical Canopy Trees under Global Warming

    NARCIS (Netherlands)

    Sterck, Frank; Anten, Niels P.R.; Schieving, Feike; Zuidema, Pieter A.

    2016-01-01

    There is a heated debate about the effect of global change on tropical forests. Many scientists predict large-scale tree mortality while others point to mitigating roles of CO2 fertilization and – the notoriously unknown – physiological trait acclimation of trees. In this opinion article we provided

  3. Short-term cold acclimation improves insulin sensitivity in patients with type 2 diabetes mellitus

    NARCIS (Netherlands)

    Hanssen, M.J.W.; Hoeks, J.; Brans, B.; Boekschoten, M.V.; Kersten, A.H.

    2015-01-01

    Cold exposure may be a potential therapy for diabetes by increasing brown adipose tissue (BAT) mass and activity. Here we report that 10 d of cold acclimation (14–15 °C) increased peripheral insulin sensitivity by ~43% in eight type 2 diabetes subjects. Basal skeletal muscle GLUT4 translocation mark

  4. Acclimation effects on critical and lethal thermal limits of workers of the Argentine ant, Linepithema humile.

    Science.gov (United States)

    Jumbam, Keafon R; Jackson, Susan; Terblanche, John S; McGeoch, Melodie A; Chown, Steven L

    2008-06-01

    For the Argentine ant Linepithema humile, bioclimatic models often predict narrower optimal temperature ranges than those suggested by behavioural and physiological studies. Although water balance characteristics of workers of this species have been thoroughly studied, gaps exist in current understanding of its thermal limits. We investigated critical thermal minima and maxima and upper and lower lethal limits following acclimation to four temperatures (15, 20, 25, 30 degrees C; 12L:12D photoperiod) in adult workers of the Argentine ant, L. humile, collected from Stellenbosch, South Africa. At an ecologically relevant rate of temperature change of 0.05 degrees Cmin(-1), CTMax varied between 38 and 40 degrees C, and CTMin varied between 0 and 0.8 degrees C. In both cases the response to acclimation was weak. A significant time by exposure temperature interaction was found for upper and lower lethal limits, with a more pronounced effect of acclimation at longer exposure durations. Upper lethal limits varied between 37 and 44 degrees C, whilst lower lethal limits varied between -4 and -10.5 degrees C, with an acclimation effect more pronounced for upper than lower lethal limits. A thermal envelope for workers of the Argentine ant is provided, demonstrating that upper thermal limits do likely contribute to distributional limits, but that lower lethal limits and limits to activity likely do not, or at least for workers who are not exposed simultaneously to the demands of load carriage and successful foraging behaviour.

  5. The relationship among metabolic rate of tree shrews (Tupaia belangeri under cold acclimation

    Directory of Open Access Journals (Sweden)

    Lin Zhang

    2012-11-01

    Full Text Available Many small mammals inhabiting cold environments display enhanced capacity for seasonal changes in nonshivering thermogenesis (NST and thermoregulatory maximum metabolic rate (MMR. However, it is not known how this plasticity remains in a mammal that rarely experiences extreme cold fluctuations. In order to answer this question, we determined body mass ( Mb, basal metabolic rate (BMR, NST, and MMR on a tree shrews (Tupaia belangeri, acclimated to cold (5 ºC conditions. NST was measured as the maximum response of metabolic rate (NSTmax after injection of norepinephrine (NE in thermoneutrality minus BMR. Maximum metabolic rate was assessed in animals exposed to enhanced heat-loss atmosphere (He-O2 connected with an open-flow respirometer. Body mass and metabolic variables increased significantly after cold acclimation with respect to control group but to a high extent (BMR, 87.97%; NST, 69.77%; and MMR, 32.35%. However, aerobic scope (MMR/BMR, and calculated shivering thermogenesis (ST did not significantly change with control group. Our data suggest: 1. The body mass and the capacity of heat production in the cold acclimated group were higher; 2. The increase of BMR and MMR during cold acclimation was the main pattern of heat production in the tree shrews.

  6. Fall Chinook Acclimation Project; Pittsburg Landing, Captain John Rapids, and Big Canyon, Annual Report 2002.

    Energy Technology Data Exchange (ETDEWEB)

    McLeod, Bruce

    2003-01-01

    Fisheries co-managers of U.S. v Oregon supported and directed the construction and operation of acclimation and release facilities for Snake River fall Chinook from Lyons Ferry Hatchery at three sites above Lower Granite Dam. In 1996, Congress instructed the U.S. Army Corps of Engineers (USCOE) to construct, under the Lower Snake River Compensation Plan (LSRCP), final rearing and acclimation facilities for fall Chinook in the Snake River basin to complement their activities and efforts in compensating for fish lost due to construction of the lower Snake River dams. The Nez Perce Tribe (NPT) played a key role in securing funding and selecting acclimation sites, then assumed responsibility for operation and maintenance of the facilities. In 1997, Bonneville Power Administrative (BPA) was directed to fund operations and maintenance (O&M) for the facilities. Two acclimation facilities, Captain John Rapids and Pittsburg Landing, are located on the Snake River between Asotin, WA and Hells Canyon Dam and one facility, Big Canyon, is located on the Clearwater River at Peck. The Capt. John Rapids facility is a single pond while the Pittsburg Landing and Big Canyon sites consist of portable fish rearing tanks assembled and disassembled each year. Acclimation of 450,000 yearling smolts (150,000 each facility) begins in March and ends 6 weeks later. When available, an additional 2,400,000 fall Chinook sub-yearlings may be acclimated for 6 weeks, following the smolt release. The project goal is to increase the naturally spawning population of Snake River fall Chinook salmon upstream of Lower Granite Dam. This is a supplementation project; in that hatchery produced fish are acclimated and released into the natural spawning habitat for the purpose of returning a greater number of spawners to increase natural production. Only Snake River stock is used and production of juveniles occurs at Lyons Ferry Hatchery. This is a long-term project, targeted to work towards achieving

  7. Does cold acclimation induce nonshivering thermogenesis in juvenile birds? Experiments with Pekin ducklings and Japanese quail chicks.

    Science.gov (United States)

    Marjoniemi, K; Hohtola, E

    2000-11-01

    The capability to produce heat in cold by nonshivering thermogenesis (NST) was studied in Pekin ducklings and Japanese quail chicks acclimated to cold for 3 weeks using indirect calorimetry (oxygen consumption) and electromyography from breast (M. pectoralis) and leg muscles (quails: M. gastrocnemius; ducklings: M. gastrocnemius, M. iliofibularis). Respiration of muscles in vitro was studied by measuring cytochrome c oxidase activity. In both species, cold acclimation induced clear morphometric and physiological changes, but no clear evidence of nonshivering thermogenesis. This was evident because increased shivering at least in one muscle coincided with increased oxygen consumption. In ducklings, however, amplitudes of shivering EMGs were low (muscles studied in both the control and cold-acclimated groups. Ducklings reacted to cold mainly by means of increasing body weight (1796 g in control, 2095 g in cold-acclimated) and circulatory changes. Acclimation did not change oxygen consumption either in vivo or in vitro. In quails, in addition to increased body weight (78.1 g control, 89.9 g cold-acclimated), improved insulation and metabolic adaptation to cold (increased respiration in vivo and in M. pectoralis in vitro) was also utilized. In Japanese quail chicks, 3 weeks of cold acclimation does not seem to induce NST, while in Pekin ducklings the existence of NST could not be totally excluded because of weak overall shivering activity.

  8. Effects of acclimation salinity on the expression of selenoproteins in the tilapia, Oreochromis mossambicus.

    Science.gov (United States)

    Seale, Lucia A; Gilman, Christy L; Moorman, Benjamin P; Berry, Marla J; Grau, E Gordon; Seale, Andre P

    2014-07-01

    Selenoproteins are ubiquitously expressed, act on a variety of physiological redox-related processes, and are mostly regulated by selenium levels in animals. To date, the expression of most selenoproteins has not been verified in euryhaline fish models. The Mozambique tilapia, Oreochromis mossambicus, a euryhaline cichlid fish, has a high tolerance for changes in salinity and survives in fresh water (FW) and seawater (SW) environments which differ greatly in selenium availability. In the present study, we searched EST databases for cichlid selenoprotein mRNAs and screened for their differential expression in FW and SW-acclimated tilapia. The expression of mRNAs encoding iodothyronine deiodinases 1, 2 and 3 (Dio1, Dio2, Dio3), Fep15, glutathione peroxidase 2, selenoproteins J, K, L, M, P, S, and W, was measured in the brain, eye, gill, kidney, liver, pituitary, muscle, and intraperitoneal white adipose tissue. Gene expression of selenophosphate synthetase 1, Secp43, and selenocysteine lyase, factors involved in selenoprotein synthesis or in selenium metabolism, were also measured. The highest variation in selenoprotein and synthesis factor mRNA expression between FW- and SW-acclimated fish was found in gill and kidney. While the branchial expression of Dio3 was increased upon transferring tilapia from SW to FW, the inverse effect was observed when fish were transferred from FW to SW. Protein content of Dio3 was higher in fish acclimated to FW than in those acclimated to SW. Together, these results outline tissue distribution of selenoproteins in FW and SW-acclimated tilapia, and indicate that at least Dio3 expression is regulated by environmental salinity.

  9. Thermal acclimation to cold alters myosin content and contractile properties of rainbow smelt, Osmerus mordax, red muscle.

    Science.gov (United States)

    Coughlin, David J; Shiels, Lisa P; Nuthakki, Seshuvardhan; Shuman, Jacie L

    2016-06-01

    Rainbow smelt (Osmerus mordax), a eurythermal fish, live in environments from -1.8 to 20°C, with some populations facing substantial annual variation in environmental temperature. These different temperature regimes pose distinct challenges to locomotion by smelt. Steady swimming performance, red muscle function and muscle myosin content were examined to assess the prediction that cold acclimation by smelt will lead to improved steady swimming performance and that any performance shift will be associated with changes in red muscle function and in its myosin heavy chain composition. Cold acclimated (4°C) smelt had a faster maximum steady swimming speed and swam with a higher tailbeat frequency than warm acclimated (10°C) smelt when tested at the same temperature (10°C). Muscle mechanics experiments demonstrated faster contractile properties in the cold acclimated fish when tested at 10°C. The red muscle of cold acclimated smelt had a shorter twitch times, a shorter relaxation times and a higher maximum shortening velocity. In addition, red muscle from cold acclimated fish displayed reduced thermal sensitivity to cold, maintaining higher force levels at 4°C compared to red muscle from warm acclimated fish. Immunohistochemistry suggests shifts in muscle myosin composition and a decrease in muscle cross-sectional area with cold acclimation. Dot blot analysis confirmed a shift in myosin content. Rainbow smelt do show a significant thermal acclimation response to cold. An examination of published values of maximum muscle shortening velocity in fishes suggests that smelt are particularly well suited to high levels of activity in very cold water. Copyright © 2016 Elsevier Inc. All rights reserved.

  10. Effects of copper, hypoxia and acute temperature shifts on mitochondrial oxidation in rainbow trout (Oncorhynchus mykiss) acclimated to warm temperature

    Energy Technology Data Exchange (ETDEWEB)

    Sappal, Ravinder [Department of Pathology and Microbiology, Atlantic Veterinary College, University of Prince Edward Island, Charlottetown, Prince Edward Island C1A 4P3 (Canada); Department of Biomedical Sciences, Atlantic Veterinary College, University of Prince Edward Island, Charlottetown, Prince Edward Island C1A 4P3 (Canada); Fast, Mark [Department of Pathology and Microbiology, Atlantic Veterinary College, University of Prince Edward Island, Charlottetown, Prince Edward Island C1A 4P3 (Canada); Stevens, Don [Department of Biomedical Sciences, Atlantic Veterinary College, University of Prince Edward Island, Charlottetown, Prince Edward Island C1A 4P3 (Canada); Kibenge, Fred [Department of Pathology and Microbiology, Atlantic Veterinary College, University of Prince Edward Island, Charlottetown, Prince Edward Island C1A 4P3 (Canada); Siah, Ahmed [British Columbia Centre for Aquatic Health Sciences, 871A Island Highway, Campbell River, British Columbia V9W 2C2 (Canada); Kamunde, Collins, E-mail: ckamunde@upei.ca [Department of Biomedical Sciences, Atlantic Veterinary College, University of Prince Edward Island, Charlottetown, Prince Edward Island C1A 4P3 (Canada)

    2015-12-15

    Highlights: • Warm acclimation reduced the electron transport system (ETS) efficiency. • Warm acclimation altered the effects of acute temperature shift, hypoxia and Cu on ETS. • Warm acclimation increased thermal sensitivity of state 3 and reduced that of state 4. • Cu stimulated while hypoxia inhibited ETS respiratory activity. • Interactions of Cu and hypoxia on the ETS and plasma metabolites were antagonistic. - Abstract: Temperature fluctuations, hypoxia and metals pollution frequently occur simultaneously or sequentially in aquatic systems and their interactions may confound interpretation of their biological impacts. With a focus on energy homeostasis, the present study examined how warm acclimation influences the responses and interactions of acute temperature shift, hypoxia and copper (Cu) exposure in fish. Rainbow trout (Oncorhynchus mykiss) were acclimated to cold (11 °C; control) and warm (20 °C) temperature for 3 weeks followed by exposure to environmentally realistic levels of Cu and hypoxia for 24 h. Subsequently, mitochondrial electron transport system (ETS) respiratory activity supported by complexes I–IV (CI–IV), plasma metabolites and condition indices were measured. Warm acclimation reduced fish condition, induced aerobic metabolism and altered the responses of fish to acute temperature shift, hypoxia and Cu. Whereas warm acclimation decelerated the ETS and increased the sensitivity of maximal oxidation rates of the proximal (CI and II) complexes to acute temperature shift, it reduced the thermal sensitivity of state 4 (proton leak). Effects of Cu with and without hypoxia were variable depending on the acclimation status and functional index. Notably, Cu stimulated respiratory activity in the proximal ETS segments, while hypoxia was mostly inhibitory and minimized the stimulatory effect of Cu. The effects of Cu and hypoxia were modified by temperature and showed reciprocal antagonistic interaction on the ETS and plasma

  11. The effects of diel-cycling hypoxia acclimation on the hypoxia tolerance, swimming capacity and growth performance of southern catfish (Silurus meridionalis).

    Science.gov (United States)

    Yang, Han; Cao, Zhen-Dong; Fu, Shi-Jian

    2013-06-01

    To investigate the effects of diel-cycling hypoxia acclimation on the hypoxia tolerance, swimming and growth performance of juvenile southern catfish, we initially measured the critical oxygen tension (P(crit)), oxygen thresholds of aquatic surface respiration (ASR) and loss of equilibrium (LOE) of diel-cycling hypoxia-acclimated (15 d, 7:00-21:00, dissolved oxygen level (DO) = 7.0 ± 0.2 mg L(-1); 21:00-7:00, DO = 3.0 ± 0.2 mg L(-1)) and non-acclimated (15 d, DO = 7.0 ± 0.2 mg L(-1)) southern catfish at 25 °C. We then measured the critical swimming speed (U(crit)) and metabolic rate (MR) of hypoxia-acclimated and non-acclimated fish (under both hypoxic and normoxic conditions). The feeding rate (FR), feeding efficiency (FE) and specific growth rate (SGR) of fish in hypoxia-acclimated and non-acclimated groups were also measured. The P(crit), ASR and LOE of hypoxia-acclimated fish were significantly lower than those of non-acclimated fish. Hypoxia acclimation resulted in a significantly higher U(crit) when the individuals swam in hypoxia. The U(crit), maximum metabolic rate (MMR) and metabolic scope (MS) of both the hypoxia-acclimated and non-acclimated fish all decreased with the decrease of DO. However, the U(crit), MMR and MS decreased by 31, 43 and 54%, respectively, in non-acclimated fish, whereas these values decreased by 15, 28 and 29%, respectively, in hypoxia-acclimated fish, which suggests that hypoxia-acclimated fish were less sensitive to the DO decrease. The FR, FE and SGR all decreased by 21, 20 and 45%, respectively, in the hypoxia-acclimated group compared to the non-acclimated group. This result suggests that diel-cycling hypoxia acclimation improved the hypoxia tolerance and aerobic swimming performance of southern catfish, whereas impaired the growth performance. The high hypoxia tolerance and physiological plasticity to hypoxia-acclimated southern catfish may be related to its lower maintenance energy expenditure, sit-and-wait lifestyle and

  12. Acclimation of fine root respiration to soil warming involves starch deposition in very fine and fine roots: a case study in Fagus sylvatica saplings.

    Science.gov (United States)

    Di Iorio, Antonino; Giacomuzzi, Valentino; Chiatante, Donato

    2016-03-01

    Root activities in terms of respiration and non-structural carbohydrates (NSC) storage and mobilization have been suggested as major physiological roles in fine root lifespan. As more frequent heat waves and drought periods within the next decades are expected, to what extent does thermal acclimation in fine roots represent a mechanism to cope with such upcoming climatic conditions? In this study, the possible changes in very fine (diameter Fagus sylvatica saplings subjected to a simulated long-lasting heat wave event and to co-occurring soil drying. For both very fine and fine roots, soil temperature (ST) resulted inversely correlated with specific root length, respiration rates and SSs concentration, but directly correlated with root mass, root tissue density and starch concentration. In particular, starch concentration increased under 28 °C for successively decreasing under 21 °C ST. These findings showed that thermal acclimation in very fine and fine roots due to 24 days exposure to high ST (∼ 28 °C), induced starch accumulation. Such 'carbon-savings strategy' should bear the maintenance costs associated to the recovery process in case of restored favorable environmental conditions, such as those occurring at the end of a heat wave event. Drought condition seems to affect the fine root vitality much more under moderate than high temperature condition, making the temporary exposure to high ST less threatening to root vitality than expected.

  13. Effects of temperament and acclimation to handling on reproductive performance of Bos taurus beef females.

    Science.gov (United States)

    Cooke, R F; Bohnert, D W; Cappellozza, B I; Mueller, C J; Delcurto, T

    2012-10-01

    Two experiments evaluated the effects of temperament and acclimation to handling on reproductive performance of Bos taurus beef females. In Exp. 1, 433 multiparous, lactating Angus × Hereford cows were sampled for blood and evaluated for temperament before the breeding season. Cow temperament was assessed by chute score and exit velocity. Chute score was assessed on a 5-point scale according to behavioral responses during chute restraining. Exit score was calculated by dividing exit velocity into quintiles and assigning cows with a score from 1 to 5 (1 = slowest, 5 = fastest cows). Temperament score was calculated by averaging chute and exit scores. Cows were classified for temperament type according to temperament score (≤ 3 = adequate, > 3 = aggressive). Plasma cortisol concentrations were greater (P temperament. Cows with aggressive temperament had reduced (P ≤ 0.05) pregnancy and calving rate and tended to have reduced (P = 0.09) weaning rate compared with cows with adequate temperament. Hence, kilogram of calf born per cow was reduced (P = 0.05) and kilogram of calf weaned per cow tended to be reduced (P = 0.08) in aggressive cows. In Exp. 2, 88 Angus × Hereford heifers (initial age = 206 ± 2 d) were weighed (d 0 and 10) and evaluated for temperament score (d 10). On d 11, heifers were ranked by these variables and assigned to receive or not (control) an acclimation treatment. Acclimated heifers were processed through a handling facility 3 times weekly for 4 wk (d 11 to 39; Mondays, Wednesdays, and Fridays), whereas control heifers remained undisturbed on pasture. Heifer puberty status, evaluated via plasma progesterone concentrations, was assessed on d 0 and 10, d 40 and 50, 70 and 80, 100 and 110, 130 and 140, 160 and 170, and 190 and 200. Blood samples collected on d 10 and 40 were also analyzed for plasma concentrations of cortisol and haptoglobin. Temperament score was assessed again on d 40 and d 200. Acclimated heifers had reduced (P = 0

  14. Local cold acclimation of the hand impairs thermal responses of the finger without improving hand neuromuscular function.

    Science.gov (United States)

    Geurts, C L M; Sleivert, G G; Cheung, S S

    2005-01-01

    To investigate the effects of cold acclimation on the thermal response and neuromuscular function of the hand. Ten healthy subjects [three female, seven male, age (mean +/- SD): 27.9 +/- 7.9 years] immersed their right hand in 8 degrees C water for 30 min, 5 days a week for 3 weeks. On the first and the last day, neuromuscular function of the first dorsal interosseus (FDI) muscle was tested. There was no significant change in maximal voluntary contraction strength or evoked contractile characteristics of the FDI after cold acclimation. Minimum finger temperature decreased significantly from 10.6 +/- 1.2 to 9.3 +/- 0.8 degrees C after 3 weeks (P cold acclimation (P cold-induced vasodilatation increased from 446 +/- 171 to 736 +/- 384 s (P cold acclimation does not enhance hand temperature or function but may put the hands at a greater risk of cold injury when exposed to the cold.

  15. Effects of acclimation temperature on thermal tolerance and membrane phospholipid composition in the fruit fly Drosophila melanogaster

    DEFF Research Database (Denmark)

    Overgaard, Johannes; Tomcala, Ales; Sørensen, Jesper G

    2008-01-01

    Adaptative responses of ectothermic organisms to thermal variation typically involve the reorganization of membrane glycerophospholipids (GPLs) to maintain membrane function. We investigated how acclimation at 15, 20 and 25 degrees C during preimaginal development influences the thermal tolerance...

  16. Consequences of acclimation on the resistance to acute thermal stress: Proteomic focus on mussels from pristine site.

    Science.gov (United States)

    Péden, Romain; Rocher, Béatrice; Chan, Philippe; Vaudry, David; Poret, Agnès; Olivier, Stéphanie; Le Foll, Frank; Bultelle, Florence

    2016-10-01

    Climate change constitutes an additional threat for intertidal species that already have to cope with a challenging environment. The present study focuses on the blue mussel Mytilus edulis and aims at investigating the importance of thermal acclimation in heat stress response. Microcosm exposures were performed with mussels submitted to an identical acute thermal stress following two thermal summer acclimations standing for present or future temperature conditions. Gill proteomes were analyzed by 2DE and 96 differentially expressed proteoforms were identified. Our results show that cell integrity appears to be maintained by the rise in molecular protective systems (i.e. Heat Shock Proteins), and by the reallocation of energy production via a switch to anaerobic metabolism and the setting up of alternative energy pathways. Finally, our results indicate that the response of mussels to acute thermal stress is conditioned by the acclimation temperature with an improved response in organisms acclimated to higher temperatures.

  17. Intraspecific variation in thermal tolerance and acclimation capacity in brook trout (Salvelinus fontinalis): physiological implications for climate change.

    Science.gov (United States)

    Stitt, Bradley C; Burness, Gary; Burgomaster, Kirsten A; Currie, Suzanne; McDermid, Jenni L; Wilson, Chris C

    2014-01-01

    Cold-water fishes are becoming increasingly vulnerable as changing thermal conditions threaten their future sustainability. Thermal stress and habitat loss from increasing water temperatures are expected to impact population viability, particularly for inland populations with limited adaptive resources. Although the long-term persistence of cold-adapted species will depend on their ability to cope with and adapt to changing thermal conditions, very little is known about the scope and variation of thermal tolerance within and among conspecific populations and evolutionary lineages. We studied the upper thermal tolerance and capacity for acclimation in three captive populations of brook trout (Salvelinus fontinalis) from different ancestral thermal environments. Populations differed in their upper thermal tolerance and capacity for acclimation, consistent with their ancestry: the northernmost strain (Lake Nipigon) had the lowest thermal tolerance, while the strain with the most southern ancestry (Hill's Lake) had the highest thermal tolerance. Standard metabolic rate increased following acclimation to warm temperatures, but the response to acclimation varied among strains, suggesting that climatic warming may have differential effects across populations. Swimming performance varied among strains and among acclimation temperatures, but strains responded in a similar way to temperature acclimation. To explore potential physiological mechanisms underlying intraspecific differences in thermal tolerance, we quantified inducible and constitutive heat shock proteins (HSP70 and HSC70, respectively). HSPs were associated with variation in thermal tolerance among strains and acclimation temperatures; HSP70 in cardiac and white muscle tissues exhibited similar patterns, whereas expression in hepatic tissue varied among acclimation temperatures but not strains. Taken together, these results suggest that populations of brook trout will vary in their ability to cope with a

  18. Heat acclimation improves intermittent sprinting in the heat but additional pre-cooling offers no further ergogenic effect.

    Science.gov (United States)

    Castle, Paul; Mackenzie, Richard W; Maxwell, Neil; Webborn, Anthony D J; Watt, Peter W

    2011-08-01

    The aim of this study was to determine the effect of 10 days of heat acclimation with and without pre-cooling on intermittent sprint exercise performance in the heat. Eight males completed three intermittent cycling sprint protocols before and after 10 days of heat acclimation. Before acclimation, one sprint protocol was conducted in control conditions (21.8 ± 2.2°C, 42.8 ± 6.7% relative humidity) and two sprint protocols in hot, humid conditions (33.3 ± 0.6°C, 52.2 ± 6.8% relative humidity) in a randomized order. One hot, humid condition was preceded by 20 min of thigh pre-cooling with ice packs (-16.2 ± 4.5°C). After heat acclimation, the two hot, humid sprint protocols were repeated. Before heat acclimation, peak power output declined in the heat (P < 0.05) but pre-cooling prevented this. Ten days of heat acclimation reduced resting rectal temperature from 37.8 ± 0.3°C to 37.4 ± 0.3°C (P < 0.01). When acclimated, peak power output increased by ∼2% (P < 0.05, main effect) and no reductions in individual sprint peak power output were observed. Additional pre-cooling offered no further ergogenic effect. Unacclimated athletes competing in the heat should pre-cool to prevent reductions in peak power output, but heat acclimate for an increased peak power output.

  19. Tracing the evolution of degraders in activated sludge during the sludge’s acclimation to a xenobiotic organic

    Science.gov (United States)

    Chong, N. M.; Fan, C. H.; Yang, Y. C.

    2017-01-01

    The molecular biology method of high-throughput pyrosequencing was employed to examine the change of activated sludge community structures during the process in which activated sludge was acclimated to and degraded a target xenobiotic. The sample xenobiotic organic compound used as the activated sludge acclimation target was the herbicide 2,4-dichlorphenoxyacetic acid (2,4-D). Indigenous activated sludge microorganisms were acclimated to 2,4-D as the sole carbon source in both the batch and the continuous-flow reaction modes. Sludge masses at multiple time points during the course of acclimation were subjected to pyrosequencing targeting the microorganisms’ 16S rRNA genes. With the bacterial 16S rRNA sequencing results the genera that increased in abundance were checked with degradative pathway databases or literature to confirm that they are commonly seen as potent degraders of 2,4-D. From this systematic examination of degrader changes at time points during activated sludge acclimation and degradation of the target xenobiotic, the trend of degrader evolution in activated sludge over the sludge’s acclimation process to a xenobiotic was traced.

  20. Photosynthetic acclimation to enriched CO{sub 2} concentrations in Pinus Ponderosa

    Energy Technology Data Exchange (ETDEWEB)

    Torres, M.P. [California State Univ., Humbolt, CA (United States)

    1995-11-01

    By the middle of the 21st century earth`s ambient CO{sub 2} level is expected to increase two-fold ({approximately}350 umol/L). Higher levels of CO{sub 2} are expected to cause major changes in the morphological, physiological, and biochemical traits of the world`s vegetation. Therefore, we constructed an experiment designed to measure the long-term acclimation processes of Pinus Ponderosa. As a prominent forest conifer, Pinus Ponderosa is useful when assessing a large scale global carbon budget. Eighteen genetically variable families were exposed to 3 different levels of CO{sub 2} (350 umol/L, 525 umol/L, 700 umol/L), for three years. Acclimation responses were quantified by assays of photosynthetic rate, chlorophyll fluorescence, and chlorophyll pigment concentrations.

  1. Temperature acclimation of growth, photosynthesis and respiration in two mesophilic phytoplankton species

    DEFF Research Database (Denmark)

    Stæhr, P. A.; Birkeland, M. J.

    2006-01-01

    Temperature acclimation in two mesophilic microalgae, Microcystis aeruginosa (Cyanobacteriales) and Scenedesmus acutus (Chlorococcales), was studied by measuring growth rate, photosynthesis, respiration, cell size, cellular pigment content and Chl a-specific light absorption. Phytoplankton were...... grown as nutrient-replete semicontinuous cultures for 2 weeks at 5, 15 and 25°C, during which growth rate was determined from changes in Chl a. Gross photosynthesis (GP) was measured as 14C assimilation at saturating light and respiration (R) was measured as O2 uptake along a temperature gradient from 0...... to 40°C. Net photosynthesis (NP) was determined as the difference between GP and R. For both species, acclimation to increasing growth temperatures resulted in increasing growth rate, cellular pigment content and decreasing cell size and Chl a-specific light absorption. Scenedesmus acutus and M...

  2. Biodegradation of toluene diamine (TDA) in activated sludge acclimated with aniline and TDA.

    Science.gov (United States)

    Asakura, S; Okazaki, S

    1995-06-01

    The biodegradability of toluene diamine (TDA) which has been regarded as a "recalcitrant compound" was examined in activated sludges. In this study, a microorganic-enzyme system which metabolized TDA was obtained by acclimating the activated sludge with aniline and TDA. In the sludge subject to be 200 days' acclimation, the considerable increase in respiration rate with the addition of TDA, accompanied the sharp decrease in its concentration. This indicated that TDA was metabolized fortuitously. The rate of biodegradation of TDA in the absence of aniline was first order with respect to its concentration when the initial TDA concentration was less than about 5 mg/l. The rate constant in this relation was proportional to mixed liquor suspended solid (MLSS). However, when the initial TDA concentration exceeded 5 mg/l, the plots were deviated from a first order rate equation.

  3. Sodium and chloride transport in soft water and hard water acclimated zebrafish (Danio rerio)

    DEFF Research Database (Denmark)

    Boisen, A M Z; Amstrup, J; Novak, I;

    2003-01-01

    While the zebrafish is commonly used for studies of developmental biology and toxicology, very little is known about their osmoregulatory physiology. The present investigation of Na(+) and Cl(-) transport revealed that the zebrafish is able to tolerate extremely low ambient ion concentrations...... and that this is achieved at least in part by a greatly enhanced apparent uptake capacity and affinity for both ions. Zebrafish maintain plasma and whole body electrolyte concentrations similar to most other freshwater teleosts even in deionized water containing only 35 microM NaCl, i.e soft water. We recorded an extremely...... inhibitor was more variable. Differential response of Na(+) uptake to amiloride depending on acclimation medium suggests that different Na(+) transport mechanisms are employed by zebrafish acclimated to soft and hard water....

  4. Thermopreference, tolerance and metabolic rate of early stages juvenile Octopus maya acclimated to different temperatures.

    Science.gov (United States)

    Noyola, Javier; Caamal-Monsreal, Claudia; Díaz, Fernando; Re, Denisse; Sánchez, Adolfo; Rosas, Carlos

    2013-01-01

    Thermopreference, tolerance and oxygen consumption rates of early juveniles Octopus maya (O. maya; weight range 0.38-0.78g) were determined after acclimating the octopuses to temperatures (18, 22, 26, and 30°C) for 20 days. The results indicated a direct relationship between preferred temperature (PT) and acclimated temperature, the PT was 23.4°C. Critical Thermal Maxima, (CTMax; 31.8±1.2, 32.7±0.9, 34.8±1.4 and 36.5±1.0) and Critical Thermal Minima, (CTMin; 11.6±0.2, 12.8±0.6, 13.7±1.0, 19.00±0.9) increased significantly (P<0.05) with increasing acclimation temperatures. The endpoint for CTMax was ink release and for CTMin was tentacles curled, respectively. A thermal tolerance polygon over the range of 18-30°C resulted in a calculated area of 210.0°C(2). The oxygen consumption rate increased significantly α=0.05 with increasing acclimation temperatures between 18 and 30°C. Maximum and minimum temperature quotients (Q10) were observed between 26-30°C and 22-26°C as 3.03 and 1.71, respectively. These results suggest that O. maya has an increased capability for adapting to moderate temperatures, and suggest increased culture potential in subtropical regions southeast of México.

  5. Photosynthetic acclimation responses of maize seedlings grown under artificial laboratory light gradients mimicking natural canopy conditions

    Directory of Open Access Journals (Sweden)

    Matthias eHirth

    2013-09-01

    Full Text Available In this study we assessed the ability of the C4 plant maize to perform long-term photosynthetic acclimation in an artificial light quality system previously used for analysing short-term and long-term acclimation responses (LTR in C3 plants. We aimed to test if this light system could be used as a tool for analysing redox-regulated acclimation processes in maize seedlings. Photosynthetic parameters obtained from maize samples harvested in the field were used as control. The results indicated that field grown maize performed a pronounced LTR with significant differences between the top and the bottom levels of the plant stand corresponding to the strong light gradients occurring in it. We compared these data to results obtained from maize seedlings grown under artificial light sources preferentially exciting either photosystem II or photosystem I. In C3 plants, this light system induces redox signals within the photosynthetic electron transport chain which trigger state transitions and differential phosphorylation of light harvesting complexes of photosystem II (LHCII. The LTR to these redox signals induces changes in the accumulation of plastid psaA transcripts, in chlorophyll (Chl fluorescence values Fs/Fm, in Chl a/b ratios and in transient starch accumulation in C3 plants. Maize seedlings grown in this light system exhibited a pronounced ability to perform both short-term and long-term acclimation at the level of psaA transcripts, Chl fluorescence values Fs/Fm and Chl a/b ratios. Interestingly, maize seedlings did not exhibit redox-controlled variations of starch accumulation probably because of its specific differences in energy metabolism. In summary, the artificial laboratory light system was found to be well-suited to mimic field light conditions and provides a physiological tool for studying the molecular regulation of the LTR of maize in more detail.

  6. Constraints to hydraulic acclimation under reduced light in two contrasting Phaseolus vulgaris cultivars.

    Science.gov (United States)

    Matzner, Steven L; Rettedal, David D; Harmon, Derek A; Beukelman, MacKenzie R

    2014-08-01

    Two cultivars of Phaseolus vulgaris L. were grown under three light levels to determine if hydraulic acclimation to light occurs in herbaceous annuals and whether intraspecific trade-offs constrain hydraulic traits. Acclimation occurred in response to reduced light and included decreased stomatal density (SD) and increased specific leaf area (SLA). Reduced light resulted in lower wood density (WD); decreased cavitation resistance, measured as the xylem pressure causing a 50 % reduction in stem conductivity (P50); and increased hydraulic capacity, measured as average leaf mass specific transpiration (E(LM)). Significant or marginally significant trade-offs between P50 and WD, WD and E(LM), and E(LM) and P50 reflected variation due to both genotype and environmental effects. A trade-off between WD and P50 within one cultivar indicated that morphological adjustment was constrained. Coordinated changes in WD, P50, and E(LM) within each cultivar in response to light were consistent with trade-offs constraining plasticity. A water-use efficiency (WUE, measured as δ(13)C) versus hydraulic capacity (E(LM)) trade-off was observed within each cultivar, further indicating that hydraulic trade-offs can constrain acclimation. Larger plants had lower hydraulic capacity (E(LM)) but greater cavitation resistance, WD, and WUE. Distinct hydraulic strategies were observed with the cultivar adapted to irrigated conditions having higher stomatal conductance and stem flow rates. The cultivar adapted to rain-fed conditions had higher leaf area and greater cavitation resistance. Hydraulic trade-offs were observed within the herbaceous P. vulgaris resulting from both genotype and environmental effects. Trade-offs within a cultivar reflected constraints to hydraulic acclimation in response to changing light.

  7. Dynamic changes in plant secondary metabolites during UV acclimation in Arabidopsis thaliana.

    Science.gov (United States)

    Hectors, Kathleen; Van Oevelen, Sandra; Geuns, Jan; Guisez, Yves; Jansen, Marcel A K; Prinsen, Els

    2014-10-01

    Plants respond to environmental stress by synthesizing a range of secondary metabolites for defense purposes. Here we report on the effect of chronic ultraviolet (UV) radiation on the accumulation of plant secondary metabolites in Arabidopsis thaliana leaves. In the natural environment, UV is a highly dynamic environmental parameter and therefore we hypothesized that plants are continuously readjusting levels of secondary metabolites. Our data show distinct kinetic profiles for accumulation of tocopherols, polyamines and flavonoids upon UV acclimation. The lipid-soluble antioxidant α-tocopherol accumulated fast and remained elevated. Polyamines accumulated fast and transiently. This fast response implies a role for α-tocopherol and polyamines in short-term UV response. In contrast, an additional sustained accumulation of flavonols took place. The distinct accumulation patterns of these secondary metabolites confirm that the UV acclimation process is a dynamic process, and indicates that commonly used single time-point analyses do not reveal the full extent of UV acclimation. We demonstrate that UV stimulates the accumulation of specific flavonol glycosides, i.e. kaempferol and (to a lesser extent) quercetin di- and triglycosides, all specifically rhamnosylated at position seven. All metabolites were identified by Ultra Performance Liquid Chromatography (UPLC)-coupled tandem mass spectrometry. Some of these flavonol glycosides reached steady-state levels in 3-4 days, while concentrations of others are still increasing after 12  days of UV exposure. A biochemical pathway for these glycosides is postulated involving 7-O-rhamnosylation for the synthesis of all eight metabolites identified. We postulate that this 7-O-rhamnosylation has an important function in UV acclimation.

  8. THE RELATIONSHIP AMONG METABOLIC RATE OF TREE SHREWS (TUPAIA BELANGERI) UNDER COLD ACCLIMATION

    OpenAIRE

    Lin Zhang; Wenrong Gao; Wenxiu Jiang; Zhengkun Wang

    2012-01-01

    Many small mammals inhabiting cold environments display enhanced capacity for seasonal changes in nonshivering thermogenesis (NST) and thermoregulatory maximum metabolic rate (MMR). However, it is not known how this plasticity remains in a mammal that rarely experiences extreme cold fluctuations. In order to answer this question, we determined body mass ( Mb), basal metabolic rate (BMR), NST, and MMR on a tree shrews (Tupaia belangeri), acclimated to cold (5 ºC) conditions. NST was measured a...

  9. Chromatic acclimation and population dynamics of green sulfur bacteria grown with spectrally tailored light

    OpenAIRE

    Saikin, Semion K.; Yadana Khin; Joonsuk Huh; Moataz Hannout; Yaya Wang; Farrokh Zare; Alán Aspuru-Guzik; Joseph Kuo-Hsiang Tang

    2014-01-01

    Living organisms have to adjust to their surrounding in order to survive in stressful conditions. We study this mechanism in one of most primitive creatures - photosynthetic green sulfur bacteria. These bacteria absorb photons very efficiently using the chlorosome antenna complexes and perform photosynthesis in extreme low-light environments. How the chlorosomes in green sulfur bacteria are acclimated to the stressful light conditions, for instance, if the spectrum of light is not optimal for...

  10. Chromatic acclimation and population dynamics of green sulfur bacteria grown with spectrally tailored light

    OpenAIRE

    Saikin, Semion K.; Khin, Yadana; Huh, Joonsuk; Hannout, Moataz; Wang, Yaya; Zare, Farrokh; Aspuru-Guzik, Alán; Tang, Joseph Kuo-Hsiang

    2014-01-01

    Living organisms have to adjust to their surrounding in order to survive in stressful conditions. We study this mechanism in one of most primitive creatures – photosynthetic green sulfur bacteria. These bacteria absorb photons very efficiently using the chlorosome antenna complexes and perform photosynthesis in extreme low-light environments. How the chlorosomes in green sulfur bacteria are acclimated to the stressful light conditions, for instance, if the spectrum of light is not optimal for...

  11. Growth and consumption of L-malic acid in wine-like medium by acclimated and non-acclimated cultures of Patagonian Oenococcus oeni strains.

    Science.gov (United States)

    Bravo-Ferrada, Bárbara Mercedes; Hollmann, Axel; Brizuela, Natalia; La Hens, Danay Valdés; Tymczyszyn, Elizabeth; Semorile, Liliana

    2016-09-01

    Five Oenococcus oeni strains, selected from spontaneous malolactic fermentation (MLF) of Patagonic Pinot noir wine, were assessed for their use as MLF starter cultures. After the individual evaluation of tolerance to some stress conditions, usually found in wine (pH, ethanol, SO2, and lysozyme), the behavior of the strains was analyzed in MLO broth with 14 % ethanol and pH 3.5 in order to test for the synergistic effect of high ethanol level and low pH and, finally, in a wine-like medium. Although the five strains were able to grow in MLO broth under low pH and/or high ethanol, they must be acclimated to grow in a wine-like medium. Additionally, glycosidase and tannase activities were evaluated, showing differences among the strains. The potential of the strains to ferment citrate was tested and two of the five strains showed the ability to metabolize this substrate. We did not detect the presence of genes encoding histidine, tyrosine descarboxylase, and putrescine carbamoyltransferase. All the strains tested exhibited good growth capacity and ability to consume L-malic acid in a wine-like medium after cell acclimation, and each of them showed a particular enzyme profile, which might confer different organoleptic properties to the wine.

  12. FUM2, a Cytosolic Fumarase, Is Essential for Acclimation to Low Temperature in Arabidopsis thaliana.

    Science.gov (United States)

    Dyson, Beth C; Miller, Matthew A E; Feil, Regina; Rattray, Nicholas; Bowsher, Caroline G; Goodacre, Royston; Lunn, John E; Johnson, Giles N

    2016-09-01

    Although cold acclimation is a key process in plants from temperate climates, the mechanisms sensing low temperature remain obscure. Here, we show that the accumulation of the organic acid fumaric acid, mediated by the cytosolic fumarase FUM2, is essential for cold acclimation of metabolism in the cold-tolerant model species Arabidopsis (Arabidopsis thaliana). A nontargeted metabolomic approach, using gas chromatography-mass spectrometry, identifies fumarate as a key component of the cold response in this species. Plants of T-DNA insertion mutants, lacking FUM2, show marked differences in their response to cold, with contrasting responses both in terms of metabolite concentrations and gene expression. The fum2 plants accumulated higher concentrations of phosphorylated sugar intermediates and of starch and malate. Transcripts for proteins involved in photosynthesis were markedly down-regulated in fum2.2 but not in wild-type Columbia-0. Plants of fum2 show a complete loss of the ability to acclimate photosynthesis to low temperature. We conclude that fumarate accumulation plays an essential role in low temperature sensing in Arabidopsis, either indirectly modulating metabolic or redox signals or possibly being itself directly involved in cold sensing.

  13. Does physiological acclimation to climate warming stabilize the ratio of canopy respiration to photosynthesis?

    Science.gov (United States)

    Drake, John E; Tjoelker, Mark G; Aspinwall, Michael J; Reich, Peter B; Barton, Craig V M; Medlyn, Belinda E; Duursma, Remko A

    2016-08-01

    Given the contrasting short-term temperature dependences of gross primary production (GPP) and autotrophic respiration, the fraction of GPP respired by trees is predicted to increase with warming, providing a positive feedback to climate change. However, physiological acclimation may dampen or eliminate this response. We measured the fluxes of aboveground respiration (Ra ), GPP and their ratio (Ra /GPP) in large, field-grown Eucalyptus tereticornis trees exposed to ambient or warmed air temperatures (+3°C). We report continuous measurements of whole-canopy CO2 exchange, direct temperature response curves of leaf and canopy respiration, leaf and branch wood respiration, and diurnal photosynthetic measurements. Warming reduced photosynthesis, whereas physiological acclimation prevented a coincident increase in Ra . Ambient and warmed trees had a common nonlinear relationship between the fraction of GPP that was respired above ground (Ra /GPP) and the mean daily temperature. Thus, warming significantly increased Ra /GPP by moving plants to higher positions on the shared Ra /GPP vs daily temperature relationship, but this effect was modest and only notable during hot conditions. Despite the physiological acclimation of autotrophic respiration to warming, increases in temperature and the frequency of heat waves may modestly increase tree Ra /GPP, contributing to a positive feedback between climate warming and atmospheric CO2 accumulation.

  14. Rediscovering leaf optical properties: New insights into plant acclimation to solar UV radiation.

    Science.gov (United States)

    Barnes, Paul W; Flint, Stephan D; Ryel, Ronald J; Tobler, Mark A; Barkley, Anne E; Wargent, Jason J

    2015-08-01

    The accumulation of UV-absorbing compounds (flavonoids and other phenylpropanoid derivatives) and resultant decrease in the UV transmittance of the epidermis in leaves (TUV), is a primary protective mechanism against the potentially deleterious effects of UV radiation and is a critical component of the overall acclimation response of plants to changing UV environments. Traditional measurements of TUV were laborious, time-consuming and destructive or invasive, thus limiting their ability to efficiently make multiple measurements of the optical properties of plants in the field. The development of rapid, nondestructive optical methods of determining TUV has permitted the examination of UV optical properties of leaves with increased replication, on a finer time scale, and enabled repeated sampling of the same leaf over time. This technology has therefore allowed for studies examining acclimation responses to UV in plants in ways not previously possible. Here we provide a brief review of these earlier studies examining leaf UV optical properties and some of their important contributions, describe the principles by which the newer non-invasive measurements of epidermal UV transmittance are made, and highlight several case studies that reveal how this technique is providing new insights into this UV acclimation response in plants, which is far more plastic and dynamic than previously thought.

  15. Effect of the fatty acid composition of acclimated oenological Lactobacillus plantarum on the resistance to ethanol.

    Science.gov (United States)

    Bravo-Ferrada, B M; Gómez-Zavaglia, A; Semorile, L; Tymczyszyn, E E

    2015-02-01

    The aim of this work was to evaluate the changes due to acclimation to ethanol on the fatty acid composition of three oenological Lactobacillus plantarum strains and their effect on the resistance to ethanol and malic acid consumption (MAC). Lactobacillus plantarum UNQLp 133, UNQLp 65.3 and UNQLp 155 were acclimated in the presence of 6 or 10% v/v ethanol, for 48 h at 28°C. Lipids were extracted to obtain fatty acid methyl esters and analysed by gas chromatography interfaced with mass spectroscopy. The influence of change in fatty acid composition on the viability and MAC in synthetic wine was analysed by determining the Pearson correlation coefficient. Acclimated strains showed a significant change in the fatty composition with regard to the nonacclimated strains. Adaptation to ethanol led to a decrease in the unsaturated/saturated ratio, mainly resulting from an increase in the contribution of short-length fatty acid C12:0 and a decrease of C18:1. The content of C12:0 was related to a higher viability after inoculation of synthetic wine. The MAC increased at higher contents in saturated fatty acid, but its efficiency was strain dependent.

  16. Differential remodeling of the lipidome during cold acclimation in natural accessions of Arabidopsis thaliana.

    Science.gov (United States)

    Degenkolbe, Thomas; Giavalisco, Patrick; Zuther, Ellen; Seiwert, Bettina; Hincha, Dirk K; Willmitzer, Lothar

    2012-12-01

    Freezing injury is a major factor limiting the geographical distribution of plant species and the growth and yield of crop plants. Plants from temperate climates are able to increase their freezing tolerance during exposure to low but non-freezing temperatures in a process termed cold acclimation. Damage to cellular membranes is the major cause of freezing injury in plants, and membrane lipid composition is strongly modified during cold acclimation. Forward and reverse genetic approaches have been used to probe the role of specific lipid-modifying enzymes in the freezing tolerance of plants. In the present paper we describe an alternative ecological genomics approach that relies on the natural genetic variation within a species. Arabidopsis thaliana has a wide geographical range throughout the Northern Hemisphere with significant natural variation in freezing tolerance that was used for a comparative analysis of the lipidomes of 15 Arabidopsis accessions using ultra-performance liquid chromatography coupled to Fourier-transform mass spectrometry, allowing the detection of 180 lipid species. After 14 days of cold acclimation at 4°C the plants from most accessions had accumulated massive amounts of storage lipids, with most of the changes in long-chain unsaturated triacylglycerides, while the total amount of membrane lipids was only slightly changed. Nevertheless, major changes in the relative amounts of different membrane lipids were also evident. The relative abundance of several lipid species was highly correlated with the freezing tolerance of the accessions, allowing the identification of possible marker lipids for plant freezing tolerance.

  17. Can leaf net carbon gain acclimate to keep up with global warming?

    Science.gov (United States)

    Vico, Giulia; Manzoni, Stefano; Way, Danielle; Hurry, Vaughan

    2016-04-01

    Plants are able to adjust their physiological activity to fluctuations and long-term changes in their growing environment. Nevertheless, projected increases in temperature will occur with unprecedented speed. Will global warming exceed the thermal acclimation capacity of leaves, thus reducing net CO2 assimilation? Such a reduction in net CO2 assimilation rate (Anet) in response to warming may deplete ecosystems' net primary productivity, with global impacts on the carbon cycling. Here we combine data on net photosynthetic thermal acclimation to changes in temperature with a probabilistic description of leaf temperature variability. We analytically obtain the probability distribution of the net CO2 assimilation rate as a function of species-specific leaf traits and growing conditions. Using this approach, we study the effects of mean leaf temperature and its variability on average Anet and the frequency of occurrence of sub-optimal thermal conditions. To maximize the net CO2 assimilation in warmer conditions, the thermal optimum for Anet (Topt) must track the growing temperature. Observations suggest that plants' thermal acclimation capacity is limited, so that growing temperatures cannot be tracked by the Topt. It is thus likely that net CO2 assimilation rates will decline in the future. Furthermore, for set leaf traits, large fluctuations in leaf temperature reduce average Anet and increase the frequency of occurrence of sub-optimal conditions for net CO2 assimilation.

  18. Co-acclimation of bacterial communities under stresses of hydrocarbons with different structures

    Science.gov (United States)

    Wang, Hui; Wang, Bin; Dong, Wenwen; Hu, Xiaoke

    2016-10-01

    Crude oil is a complex mixture of hydrocarbons with different structures; its components vary in bioavailability and toxicity. It is important to understand how bacterial communities response to different hydrocarbons and their co-acclimation in the process of degradation. In this study, microcosms with the addition of structurally different hydrocarbons were setup to investigate the successions of bacterial communities and the interactions between different bacterial taxa. Hydrocarbons were effectively degraded in all microcosms after 40 days. High-throughput sequencing offered a great quantity of data for analyzing successions of bacterial communities. The results indicated that the bacterial communities responded dramatically different to various hydrocarbons. KEGG database and PICRUSt were applied to predict functions of individual bacterial taxa and networks were constructed to analyze co-acclimations between functional bacterial groups. Almost all functional genes catalyzing degradation of different hydrocarbons were predicted in bacterial communities. Most of bacterial taxa were believed to conduct biodegradation processes via interactions with each other. This study addressed a few investigated area of bacterial community responses to structurally different organic pollutants and their co-acclimation and interactions in the process of biodegradation. The study could provide useful information to guide the bioremediation of crude oil pollution.

  19. Acclimation and adaptation to common marine pollutants in the copepod Tigriopus californicus.

    Science.gov (United States)

    Sun, Patrick Y; Foley, Helen B; Handschumacher, Lisa; Suzuki, Amanda; Karamanukyan, Tigran; Edmands, Suzanne

    2014-10-01

    Establishing water quality criteria using bioassays is complicated by variation in chemical tolerance between populations. Two major contributors to this variation are acclimation and adaptation, which are both linked to exposure history, but differ in how long their effects are maintained. Our study examines how tolerance changes over multiple generations of exposure to two common marine pollutants, copper (Cu) and tributyltin oxide (TBTO), in a sexually reproducing marine copepod, Tigriopus californicus. Lines of T. californicus were chronically exposed to sub-lethal levels of Cu and TBTO for 12 generations followed by a recovery period of 3 generations in seawater control conditions. At each generation, the average number of offspring produced and survived to 28 d was determined and used as the metric of tolerance. Lines exposed to Cu and TBTO showed an overall increase in tolerance over time. Increased Cu tolerance arose by generation 3 in the chronically exposed lines and was lost after 3 generations in seawater control conditions. Increased TBTO tolerance was detected at generation 7 and was maintained even after 3 generations in seawater control conditions. It was concluded from this study that tolerance to Cu is consistent with acclimation, a quick gain and loss of tolerance. In contrast, TBTO tolerance is consistent with adaptation, in which onset of tolerance was delayed relative to an acclimation response and maintained in the absence of exposure. These findings illustrate that consideration of exposure history is necessary when using bioassays to measure chemical tolerance.

  20. Effects of freezing and cold acclimation on the plasma membrane of isolated protoplasts, progress report

    Energy Technology Data Exchange (ETDEWEB)

    Steponkus, P L

    1993-01-01

    Our goal is to provide a mechanistic understanding of the cellular and molecular aspects of freezing injury and cold acclimation from a perspective of the structural and functional integrity of the plasma membrane -- the primary site of freezing injury in winter cereals. We have utilized protoplasts isolated from leaves of winter rye (Secale cereale L. cv Puma) to study the cryobehavior of the plasma membrane during a freeze/thaw cycle. The focus of our current studies is on lesions in the plasma membrane that result from severe freeze-induced dehydration and result in the alteration of the semipermeable characteristics of the plasma membrane so that the protoplasts are osmotically unresponsive. In protoplasts isolated from non-acclimated rye leaves (NA protoplasts), injury is associated with the formation of aparticulate domains in the plasma membrane, aparticulate lamellae subtending the plasma membrane, and lamellar-to-hexagonal II phase transitions in the plasma membrane and the subtending lamellae. However, lamellar-to-hexagonal II phase transitions are not observed following severe dehydration of protoplasts isolated from cold-acclimated rye leaves (ACC protoplasts). Rather, injury is associated with the fracture-jump lesion,'' which, in freeze-fracture electron microscopy studies, is manifested as localized deviations in the fracture face of the plasma membrane. The fracture plane jumps'' from the plasma membrane to either subtending aparticulate lamellae or aparticulate regions of various endomembranes (predominantly chloroplast envelopes) that are in close apposition with the plasma membrane.

  1. Cold acclimation induced accumulation of phenolic compounds and freezing tolerance in Ammopiptanthus mongolicus

    Institute of Scientific and Technical Information of China (English)

    Liu Mei-qin; Chen Yi-yin; Lu Cun-fu; Zhang Hui; Yin Wei-lun

    2007-01-01

    Ammopiptanthus mongolicus, the only freezing tolerant evergreen broad-leaved shrub, local species of the Alashan desert,northwest sand area of China, can survive -30℃ or even lower temperature in winter. In the present study, the secondary products phenolics in A. mongolicus cotyledons were determined to study the effects ofphenolics on cold tolerance. Cytochemical localization of phenolics in cotyledon cells was observed by electron microscopy and the content of phenolic compounds was assayed by spectrophotometric measurement. The results showed that the freezing tolerance of A. mongolicus seedlings increased after acclimation at 2-6℃ for 14 days, which accompanied the increase of the content of phenolic compounds in cotyledons. Cytochemical observation showed that phenolic deposits were mainly localized in vacuoles and in close proximity to tonoplast, and also in the cytoplasm. The amount and the size of phenolics droplets increased obviously in cytoplasm and vacuoles after cold acclimation, predominantly aggregated along membranes of vacuoles and tonoplast. No phenolic deposits were found in cell walls. As hydrogen- or electron-donating agents, phenolics may protect plant cells against reactive oxygen species formed during chilling or freezing stress and improve the freezing tolerance of cold-acclimated A. mongolicus seedlings.

  2. Study of kinetics of degradation of cyclohexane carboxylic acid by acclimated activated sludge.

    Science.gov (United States)

    Wang, Chunhua; Shi, Shuian; Chen, Hongyan

    2016-01-01

    Activated sludge contains complex microorganisms, which are highly effective biodegrading agents. In this study, the kinetics of biodegradation of cyclohexane carboxylic acid (CHCA) by an acclimated aerobic activated sludge were investigated. The results showed that after 180 days of acclimation, the activated sludge could steadily degrade >90% of the CHCA in 120 h. The degradation of CHCA by the acclimated activated sludge could be modeled using a first-order kinetics equation. The equations for the degradation kinetics for different initial CHCA concentrations were also obtained. The kinetics constant, kd, decreased with an increase in the CHCA concentration, indicating that, at high concentrations, CHCA had an inhibiting effect on the microorganisms in the activated sludge. The effects of pH on the degradation kinetics of CHCA were also investigated. The results showed that a pH of 10 afforded the highest degradation rate, indicating that basic conditions significantly promoted the degradation of CHCA. Moreover, it was found that the degradation efficiency for CHCA increased with an increase in temperature and concentration of dissolved oxygen under the experimental conditions.

  3. Biological removal of phenol from saline wastewater using a moving bed biofilm reactor containing acclimated mixed consortia.

    Science.gov (United States)

    Nakhli, Seyyed Ali Akbar; Ahmadizadeh, Kimia; Fereshtehnejad, Mahmood; Rostami, Mohammad Hossein; Safari, Mojtaba; Borghei, Seyyed Mehdi

    2014-01-01

    In this study, the performance of an aerobic moving bed biofilm reactor (MBBR) was assessed for the removal of phenol as the sole substrate from saline wastewater. The effect of several parameters namely inlet phenol concentration (200-1200 mg/L), hydraulic retention time (8-24 h), inlet salt content (10-70 g/L), phenol shock loading, hydraulic shock loading and salt shock loading on the performance of the 10 L MBBR inoculated with a mixed culture of active biomass gradually acclimated to phenol and salt were evaluated in terms of phenol and chemical oxygen demand (COD) removal efficiencies. The results indicated that phenol and COD removal efficiencies are affected by HRT, phenol and salt concentration in the bioreactor saline feed. The MBBR could remove up to 99% of phenol and COD from the feed saline wastewater at inlet phenol concentrations up to 800 mg/L, HRT of 18 h and inlet salt contents up to 40 g/L. The reactor could also resist strong shock loads. Furthermore, measuring biological quantitative parameters indicated that the biofilm plays a main role in phenol removal. Overall, the results of this investigation revealed that the developed MBBR system with high concentration of the active mixed biomass can play a prominent role in order to treat saline wastewaters containing phenol in industrial applications as a very efficient and flexible technology.

  4. Effects of heat acclimation on hand cooling efficacy following exercise in the heat.

    Science.gov (United States)

    Adams, Elizabeth L; Vandermark, Lesley W; Pryor, J Luke; Pryor, Riana R; VanScoy, Rachel M; Denegar, Craig R; Huggins, Robert A; Casa, Douglas J

    2017-05-01

    This study examined the separate and combined effects of heat acclimation and hand cooling on post-exercise cooling rates following bouts of exercise in the heat. Seventeen non-heat acclimated (NHA) males (mean ± SE; age, 23 ± 1 y; mass, 75.30 ± 2.27 kg; maximal oxygen consumption [VO2 max], 54.1 ± 1.3 ml·kg(-1)·min(-1)) completed 2 heat stress tests (HST) when NHA, then 10 days of heat acclimation, then 2 HST once heat acclimated (HA) in an environmental chamber (40°C; 40%RH). HSTs were 2 60-min bouts of treadmill exercise (45% VO2 max; 2% grade) each followed by 10 min of hand cooling (C) or no cooling (NC). Heat acclimation sessions were 90-240 min of treadmill or stationary bike exercise (60-80% VO2 max). Repeated measures ANOVA with Fishers LSD post hoc (α < 0.05) identified differences. When NHA, C (0.020 ± 0.003°C·min(-1)) had a greater cooling rate than NC (0.013 ± 0.003°C·min(-1)) (mean difference [95%CI]; 0.007°C [0.001,0.013], P = 0.035). Once HA, C (0.021 ± 0.002°C·min(-1)) was similar to NC (0.025 ± 0.002°C·min(-1)) (0.004°C [-0.003,0.011], P = 0.216). Hand cooling when HA (0.021 ± 0.002°C·min(-1)) was similar to when NHA (0.020 ± 0.003°C·min(-1)) (P = 0.77). In conclusion, when NHA, C provided greater cooling rates than NC. Once HA, C and NC provided similar cooling rates.

  5. Exogenous thyroid hormones regulate the activity of citrate synthase and cytochrome c oxidase in warm- but not cold-acclimated lake whitefish (Coregonus clupeaformis)

    Science.gov (United States)

    Zak, Megan A.; Regish, Amy M.; McCormick, Stephen; Manzon, Richard G.

    2017-01-01

    Thermal acclimation is known to elicit metabolic adjustments in ectotherms, but the cellular mechanisms and endocrine control of these shifts have not been fully elucidated. Here we examined the relationship between thermal acclimation, thyroid hormones and oxidative metabolism in juvenile lake whitefish. Impacts of thermal acclimation above (19 °C) or below (8 °C) the thermal optimum (13 °C) and exposure to exogenous thyroid hormone (60 µg T4/g body weight) were assessed by quantifying citrate synthase and cytochrome c oxidase activities in liver, red muscle, white muscle and heart. Warm acclimation decreased citrate synthase activity in liver and elevated both citrate synthase and cytochrome c oxidase activities in red muscle. In contrast, induction of hyperthyroidism in warm-acclimated fish stimulated a significant increase in liver citrate synthase and heart cytochrome c oxidase activities, and a decrease in the activity of both enzymes in red muscle. No change in citrate synthase or cytochrome c oxidase activities was observed following cold acclimation in either the presence or absence of exogenous thyroid hormones. Collectively, our results indicate that thyroid hormones influence the activity of oxidative enzymes more strongly in warm-acclimated than in cold-acclimated lake whitefish, and they may play a role in mediating metabolic adjustments observed during thermal acclimation.

  6. Exogenous thyroid hormones regulate the activity of citrate synthase and cytochrome c oxidase in warm- but not cold-acclimated lake whitefish (Coregonus clupeaformis).

    Science.gov (United States)

    Zak, Megan A; Regish, Amy M; McCormick, Stephen D; Manzon, Richard G

    2017-02-14

    Thermal acclimation is known to elicit metabolic adjustments in ectotherms, but the cellular mechanisms and endocrine control of these shifts have not been fully elucidated. Here we examined the relationship between thermal acclimation, thyroid hormones and oxidative metabolism in juvenile lake whitefish. Impacts of thermal acclimation above (19 °C) or below (8 °C) the thermal optimum (13 °C) and exposure to exogenous thyroid hormone (60 µg T4/g body weight) were assessed by quantifying citrate synthase and cytochrome c oxidase activities in liver, red muscle, white muscle and heart. Warm acclimation decreased citrate synthase activity in liver and elevated both citrate synthase and cytochrome c oxidase activities in red muscle. In contrast, induction of hyperthyroidism in warm-acclimated fish stimulated a significant increase in liver citrate synthase and heart cytochrome c oxidase activities, and a decrease in the activity of both enzymes in red muscle. No change in citrate synthase or cytochrome c oxidase activities was observed following cold acclimation in either the presence or absence of exogenous thyroid hormones. Collectively, our results indicate that thyroid hormones influence the activity of oxidative enzymes more strongly in warm-acclimated than in cold-acclimated lake whitefish, and they may play a role in mediating metabolic adjustments observed during thermal acclimation.

  7. Responses of action potential and K+ currents to temperature acclimation in fish hearts: phylogeny or thermal preferences?

    Science.gov (United States)

    Haverinen, Jaakko; Vornanen, Matti

    2009-01-01

    Electrical activity of the heart is assumed to be one of the key factors that set thermal tolerance limits for ectothermic vertebrates. Therefore, we hypothesized that in thermal acclimation--the duration of cardiac action potential and the repolarizing K+ currents that regulate action potential duration (APD)--the rapid component of the delayed rectifier K+ current (I(Kr)) and the inward rectifier K+ current (I(K1)) are more plastic in eurythermal than in stenothermal fish species. The hypothesis was tested in six freshwater teleosts representing four different fish orders (Cadiformes, Cypriniformes, Perciformes, Salmoniformes) acclimated at +4 degrees C (cold acclimation) or +18 degrees C (warm acclimation). In cold acclimation, a compensatory shortening of APD occurred in all species regardless of thermal tolerances, life styles, or phylogenies of the fish, suggesting that this response is a common characteristic of the teleost heart. The strength of the response did not, however, obey simple eurythermy-stenothermy gradation but differed among the phylogenetic groups. Salmoniformes fish showed the greatest acclimation capacity of cardiac electrical activity, whereas the weakest response appeared in the perch (Perciformes) heart. The underlying ionic mechanisms were also partly phylogeny dependent. Modification of the I(Kr) current was al- most ubiquitously involved in acclimation response of fish cardiac myocytes to temperature, while the ability to change the I(K1) current under chronic thermal stress was absent or showed inverse compensation in Salmoniformes species. Thus, in Salmoniformes fish, the thermal plasticity of APD is strongly based on I(Kr), while other fish groups rely on both I(Kr) and I(K1).

  8. Plasma membrane lipid alterations associated with cold acclimation of winter rye seedlings (Secale cereale L. cv Puma)

    Energy Technology Data Exchange (ETDEWEB)

    Lynch, D.V.; Steponkus, P.L. (Cornell Univ., Ithaca, NY (USA))

    1987-01-01

    Highly enriched plasma membrane fractions were isolated from leaves of nonacclimated (NA) and acclimated (ACC) rye (Secale cereale L. cv Puma) seedlings. Collectively, free sterols, steryl glucosides, and acylated steryl glucosides constituted > 50 mole % of the total lipid in both NA and ACC plasma membrane fractions. Glucocerebrosides containing hydroxy fatty acids constituted the major glycolipid class of the plasma membrane, accounting for 16 mole % of the total lipid. Phospholipids, primarily phosphatidylcholine and phosphatidylethanolamine with lesser amounts of phosphatidylglycerol, phosphatidic acid, phosphatidylserine, and phosphatidylinositol, comprised only 32 mole% of the total lipid in NA samples. Following cold acclimation, free sterols increased from 33 to 44 mole %, while steryl glucosides and acylated steryl glucosides decreased from 15 to 6 mole % and 4 to 1 mole %, respectively. Sterol analyses of these lipid classes demonstrated that free {beta}-sitosterol increased from 21 to 32 mole % (accounting for the increase in free sterols as a class) at the expense of sterol derivatives containing {beta}-sitosterol. Glucocerebrosides decreased from 16 to 7 mole % of the total lipid following cold acclimation. In addition, the relative proportions of associated hydroxy fatty acids, including 22:0 (h), 24:0 (h), 22:1 (h), and 24:1 (h) were altered. The phospholipid content of the plasma membrane fraction increased to 42 mole % of the total lipid following cold acclimation. Although the relative proportions of the individual phospholipids did not change appreciably after cold acclimation, there were substantial differences in the molecular species. Di-unsaturated molecular species of phosphatidylcholine and phosphatidylethanolamine increased following acclimation. These results demonstrate that cold acclimation results in substantial changes in the lipid composition of the plasma membrane.

  9. Adaptive modification of membrane phospholipid fatty acid composition and metabolic thermosuppression of brown adipose tissue in heat-acclimated rats

    Science.gov (United States)

    Saha, S. K.; Ohno, T.; Tsuchiya, K.; Kuroshima, A.

    Thermogenesis, especially facultative thermogenesis by brown adipose tissue (BAT), is less important in high ambient temperature and the heat-acclimated animals show a lower metabolic rate. Adaptive changes in the metabolic activity of BAT are generally found to be associated with a modification of membrane phospholipid fatty acid composition. However, the effect of heat acclimation on membrane phospholipid fatty acid composition is as yet unknown. In this study, we examined the thermogenic activity and phospholipid fatty acid composition of interscapular BAT from heat-acclimated rats (control: 25+/-1°C, 50% relative humidity and heat acclimation: 32+/-0.5°C, 50% relative humidity). Basal thermogenesis and the total thermogenic capacity after noradrenaline stimulation, as estimated by in vitro oxygen consumption of BAT (measured polarographically using about 1-mm3 tissue blocks), were smaller in the heat-acclimated group than in the control group. There was no difference in the tissue content of phospholipids between the groups when expressed per microgram of DNA. The phospholipid fatty acid composition was analyzed by a capillary gas chromatograph. The state of phospholipid unsaturation, as estimated by the number of double bonds per fatty acid molecule, was similar between the groups. The saturated fatty acid level was higher in the heat-acclimated group. Among the unsaturated fatty acids, heat acclimation decreased docosahexaenoic acid and oleic acid levels, and increased the arachidonic acid level. The tissue level of docosahexaenoic acid correlated with the basal oxygen consumption of BAT (r=0.6, Pfatty acids, especially the n-3 polyunsaturated fatty acid docosahexaenoic acid, which is possibly involved in the metabolic thermosuppression.

  10. Global Transcriptome Analysis Reveals Acclimation-Primed Processes Involved in the Acquisition of Desiccation Tolerance in Boea hygrometrica.

    Science.gov (United States)

    Zhu, Yan; Wang, Bo; Phillips, Jonathan; Zhang, Zhen-Nan; Du, Hong; Xu, Tao; Huang, Lian-Cheng; Zhang, Xiao-Fei; Xu, Guang-Hui; Li, Wen-Long; Wang, Zhi; Wang, Ling; Liu, Yong-Xiu; Deng, Xin

    2015-07-01

    Boea hygrometrica resurrection plants require a period of acclimation by slow soil-drying in order to survive a subsequent period of rapid desiccation. The molecular basis of this observation was investigated by comparing gene expression profiles under different degrees of water deprivation. Transcripts were clustered according to the expression profiles in plants that were air-dried (rapid desiccation), soil-dried (gradual desiccation), rehydrated (acclimated) and air-dried after acclimation. Although phenotypically indistinguishable, it was shown by principal component analysis that the gene expression profiles in rehydrated, acclimated plants resemble those of desiccated plants more closely than those of hydrated acclimated plants. Enrichment analysis based on gene ontology was performed to deconvolute the processes that accompanied desiccation tolerance. Transcripts associated with autophagy and α-tocopherol accumulation were found to be activated in both air-dried, acclimated plants and soil-dried non-acclimated plants. Furthermore, transcripts associated with biosynthesis of ascorbic acid, cell wall catabolism, chaperone-assisted protein folding, respiration and macromolecule catabolism were activated and maintained during soil-drying and rehydration. Based on these findings, we hypothesize that activation of these processes leads to the establishment of an optimal physiological and cellular state that enables tolerance during rapid air-drying. Our study provides a novel insight into the transcriptional regulation of critical priming responses to enable survival following rapid dehydration in B. hygrometrica. © The Author 2015. Published by Oxford University Press on behalf of Japanese Society of Plant Physiologists. All rights reserved. For permissions, please email: journals.permissions@oup.com.

  11. Temperature response of photosynthesis in C3, C4, and CAM plants: temperature acclimation and temperature adaptation.

    Science.gov (United States)

    Yamori, Wataru; Hikosaka, Kouki; Way, Danielle A

    2014-02-01

    Most plants show considerable capacity to adjust their photosynthetic characteristics to their growth temperatures (temperature acclimation). The most typical case is a shift in the optimum temperature for photosynthesis, which can maximize the photosynthetic rate at the growth temperature. These plastic adjustments can allow plants to photosynthesize more efficiently at their new growth temperatures. In this review article, we summarize the basic differences in photosynthetic reactions in C3, C4, and CAM plants. We review the current understanding of the temperature responses of C3, C4, and CAM photosynthesis, and then discuss the underlying physiological and biochemical mechanisms for temperature acclimation of photosynthesis in each photosynthetic type. Finally, we use the published data to evaluate the extent of photosynthetic temperature acclimation in higher plants, and analyze which plant groups (i.e., photosynthetic types and functional types) have a greater inherent ability for photosynthetic acclimation to temperature than others, since there have been reported interspecific variations in this ability. We found that the inherent ability for temperature acclimation of photosynthesis was different: (1) among C3, C4, and CAM species; and (2) among functional types within C3 plants. C3 plants generally had a greater ability for temperature acclimation of photosynthesis across a broad temperature range, CAM plants acclimated day and night photosynthetic process differentially to temperature, and C4 plants was adapted to warm environments. Moreover, within C3 species, evergreen woody plants and perennial herbaceous plants showed greater temperature homeostasis of photosynthesis (i.e., the photosynthetic rate at high-growth temperature divided by that at low-growth temperature was close to 1.0) than deciduous woody plants and annual herbaceous plants, indicating that photosynthetic acclimation would be particularly important in perennial, long-lived species that

  12. Plant Growth under Natural Light Conditions Provides Highly Flexible Short-Term Acclimation Properties toward High Light Stress

    Science.gov (United States)

    Schumann, Tobias; Paul, Suman; Melzer, Michael; Dörmann, Peter; Jahns, Peter

    2017-01-01

    Efficient acclimation to different growth light intensities is essential for plant fitness. So far, most studies on light acclimation have been conducted with plants grown under different constant light regimes, but more recent work indicated that acclimation to fluctuating light or field conditions may result in different physiological properties of plants. Thale cress (Arabidopsis thaliana) was grown under three different constant light intensities (LL: 25 μmol photons m−2 s−1; NL: 100 μmol photons m−2 s−1; HL: 500 μmol photons m−2 s−1) and under natural fluctuating light (NatL) conditions. We performed a thorough characterization of the morphological, physiological, and biochemical properties focusing on photo-protective mechanisms. Our analyses corroborated the known properties of LL, NL, and HL plants. NatL plants, however, were found to combine characteristics of both LL and HL grown plants, leading to efficient and unique light utilization capacities. Strikingly, the high energy dissipation capacity of NatL plants correlated with increased dynamics of thylakoid membrane reorganization upon short-term acclimation to excess light. We conclude that the thylakoid membrane organization and particularly the light-dependent and reversible unstacking of grana membranes likely represent key factors that provide the basis for the high acclimation capacity of NatL grown plants to rapidly changing light intensities. PMID:28515734

  13. Effects of seawater acclimation on mRNA levels of corticosteroid receptor genes in osmoregulatory and immune systems in trout

    Science.gov (United States)

    Yada, T.; Hyodo, S.; Schreck, C.B.

    2008-01-01

    Influence of environmental salinity on expression of distinct corticosteroid receptor (CR) genes, glucocorticoid receptor (GR)-1 and -2, and mineralcorticoid receptor (MR), was examined in osmoregulatory and hemopoietic organs and leucocytes of steelhead trout (Oncorhynchus mykiss). There was no significant difference in plasma cortisol levels between freshwater (FW)- or seawater (SW)-acclimated trout, whereas Na+, K+-ATPase was activated in gill of SW fish. Plasma lysozyme levels also showed a significant increase after acclimation to SW. In SW-acclimated fish, mRNA levels of GR-1, GR-2, and MR were significantly higher in gill and body kidney than those in FW. Head kidney and spleen showed no significant change in these CR mRNA levels after SW-acclimation. On the other hand, leucocytes isolated from head kidney and peripheral blood showed significant decreases in mRNA levels of CR in SW-acclimated fish. These results showed differential regulation of gene expression of CR between osmoregulatory and immune systems. ?? 2008 Elsevier Inc. All rights reserved.

  14. Photosynthesis acclimation, leaf nitrogen concentration, and growth of four tree species over 3 years in response to elevated carbon dioxide and nitrogen treatment in subtropical China

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Juxiu; Zhou, Guoyi; Duan, Honglang; Li, Yuelin; Zhang, Deqiang [Chinese Academy of Sciences, Guangzhou (China). South China Botanical Garden; Xu, Zhihong [Griffith Univ., Nathan, Brisbane (Australia). Centre for Forestry and Horticultural Research

    2011-10-15

    Up to date, most studies about the plant photosynthetic acclimation responses to elevated carbon dioxide (CO{sub 2}) concentration have been performed in temperate areas, which are often N limited under natural conditions and with low ambient N deposition. It is unclear whether photosynthetic downregulation is alleviated with increased N availability, for example, from increased N deposition due to fossil fuel combustion in the tropics and subtropics. Awareness of plant photosynthetic responses to elevated CO{sub 2} concentration will contribute to the better understanding and prediction of future forest productivity under global change. Four tree species, Schima superba Gardn. et Champ., Ormosia pinnata (Lour.) Merr, Castanopsis hystrix AC. DC., and Acmena acuminatissima (Blume) Merr. et Perry were exposed to a factorial combination of atmospheric CO{sub 2} concentration (ambient and elevated CO{sub 2} concentration at ca. 700 {mu}mol CO{sub 2} mol{sup -1}) and N deposition (ambient and ambient + 100 kg N ha{sup -1} year{sup -1}) in open-top chambers in southern China for 3 years since March 2005. Light-saturated net photosynthetic rate, leaf N concentration, and tree growth of all species were measured. The CO{sub 2} treatments did not affect light-saturated net photosynthetic rate of all species grown with the high N treatment. However, S. superba grown with the low N treatment (ambient) had 23% and 47% greater net photosynthesis in the ambient CO{sub 2} concentration than those in the elevated CO{sub 2} concentration for December 2006 and November 2007 (20 and 31 months after the treatments were applied), respectively, and A. acuminatissima grown with the low N treatment had 173%, 26%, and 121% greater net photosynthesis in trees grown in the ambient CO{sub 2} concentration than those in the elevated CO{sub 2} concentration for July 2006 (16 months after the treatments), December 2006 (20 months), and November 2007 (31 months), respectively, whereas

  15. Unlocking the Constraints of Cyanobacterial Productivity: Acclimations Enabling Ultrafast Growth

    Directory of Open Access Journals (Sweden)

    Hans C. Bernstein

    2016-07-01

    Full Text Available Harnessing the metabolic potential of photosynthetic microbes for next-generation biotechnology objectives requires detailed scientific understanding of the physiological constraints and regulatory controls affecting carbon partitioning between biomass, metabolite storage pools, and bioproduct synthesis. We dissected the cellular mechanisms underlying the remarkable physiological robustness of the euryhaline unicellular cyanobacterium Synechococcus sp. strain PCC 7002 (Synechococcus 7002 and identify key mechanisms that allow cyanobacteria to achieve unprecedented photoautotrophic productivities (~2.5-h doubling time. Ultrafast growth of Synechococcus 7002 was supported by high rates of photosynthetic electron transfer and linked to significantly elevated transcription of precursor biosynthesis and protein translation machinery. Notably, no growth or photosynthesis inhibition signatures were observed under any of the tested experimental conditions. Finally, the ultrafast growth in Synechococcus 7002 was also linked to a 300% expansion of average cell volume. We hypothesize that this cellular adaptation is required at high irradiances to support higher cell division rates and reduce deleterious effects, corresponding to high light, through increased carbon and reductant sequestration.

  16. Ecohydrological responses of dense canopies to environmental variability: 2. Role of acclimation under elevated CO2

    Science.gov (United States)

    Drewry, D. T.; Kumar, P.; Long, S.; Bernacchi, C.; Liang, X.-Z.; Sivapalan, M.

    2010-12-01

    The ability to accurately predict land-atmosphere exchange of mass, energy, and momentum over the coming century requires the consideration of plant biochemical, ecophysiological, and structural acclimation to modifications of the ambient environment. Amongst the most important environmental changes experienced by terrestrial vegetation over the last century has been the increase in ambient carbon dioxide (CO2) concentrations, with a projected doubling in CO2 from preindustrial levels by the middle of this century. This change in atmospheric composition has been demonstrated to significantly alter a variety of leaf and plant properties across a range of species, with the potential to modify land-atmosphere interactions and their associated feedbacks. Free Air Carbon Enrichment (FACE) technology has provided significant insight into the functioning of vegetation in natural conditions under elevated CO2, but remains limited in its ability to quantify the exchange of CO2, water vapor, and energy at the canopy scale. This paper addresses the roles of ecophysiological, biochemical, and structural plant acclimation on canopy-scale exchange of CO2, water vapor, and energy through the application of a multilayer canopy-root-soil model (MLCan) capable of resolving changes induced by elevated CO2 through the canopy and soil systems. Previous validation of MLCan flux estimates were made for soybean and maize in the companion paper using a record of six growing seasons of eddy covariance data from the Bondville Ameriflux site. Observations of leaf-level photosynthesis, stomatal conductance, and surface temperature collected at the SoyFACE experimental facility in central Illinois provide a basis for examining the ability of MLCan to capture vegetation responses to an enriched CO2 environment. Simulations of control (370 [ppm]) and elevated (550 [ppm]) CO2 environments allow for an examination of the vertical variation and canopy-scale responses of vegetation states and fluxes

  17. Acclimation to different depths by the marine angiosperm Posidonia oceanica: transcriptomic and proteomic profiles

    Directory of Open Access Journals (Sweden)

    Emanuela eDattolo

    2013-06-01

    Full Text Available For seagrasses, seasonal and daily variations in light and temperature represent the mains factors driving their distribution along the bathymetric cline. Changes in these environmental factors, due to climatic and anthropogenic effects, can compromise their survival. In a framework of conservation and restoration, it becomes crucial to improve our knowledge about the physiological plasticity of seagrass species along environmental gradients. Here, we aimed to identify differences in transcriptomic and proteomic profiles, involved in the acclimation along the depth gradient in the seagrass Posidonia oceanica, and to improve the available molecular resources in this species, which is an important requisite for the application of eco-genomic approaches. To do that, from plant growing in the shallow (-5m and a deep (-25m portions of a single meadow, (i we generated two reciprocal EST (Expressed Sequences Tags libraries using a Suppressive Subtractive Hybridization (SSH approach, to obtain depth/specific transcriptional profiles, and (ii we identified proteins differentially expressed, using the highly innovative USIS mass spectrometry methodology, coupled with 1D-SDS electrophoresis and labeling free approach. Mass spectra were searched in the open source Global Proteome Machine (GPM engine against plant databases and with the X!Tandem algorithm against a local database. Transcriptional analysis showed both quantitative and qualitative differences between depths. EST libraries had only the 3% of transcripts in common. A total of 315 peptides belonging to 64 proteins were identified by mass spectrometry. ATP synthase subunits were among the most abundant proteins in both conditions. Both approaches identified genes and proteins in pathways related to energy metabolism, transport and genetic information processing, that appear o be the most involved in depth acclimation in P. oceanica. Their putative rules in acclimation to depth were discussed.

  18. Effect of warm-rearing and heat acclimation on pituitary-gonadal axis in male rats.

    Science.gov (United States)

    Kurowicka, B; Gajewska, A; Amarowicz, R; Kotwica, G

    2008-12-01

    Plasma gonadotrophic and testicular hormones concentrations in both immature and adult male rats exposed to 34 degrees C of ambient temperature were determined. In vitro steroidogenic ability of interstitial cells from experimental rats was also studied. Four groups of rats (n = 45) were used. Warm-reared (WR) males were housed in 34 degrees C and control-reared rats in 20 degrees C from birth to adulthood. The other groups were acclimated to 34 degrees C [warm-acclimated (WA) group] or 20 degrees C [deacclimated (DA) group] as adults. Decreased body weight and testis weight (p < 0.05) was found in heat-exposed groups, but relative testis weight was unchanged in WA and increased (p < 0.05) in WR and DA males. Plasma luteinizing hormone (LH) concentration increased in WA and DA males. Increased (p < 0.05) follicle-stimulating hormone (FSH) and prolactin plasma levels were found in DA and WR groups respectively. WA males had decreased testosterone (T) and WR rats androstenedione (A(4)) plasma concentration (p < 0.05). Interstitial cells (43% of them were Leydig cells by 3beta-hydroxysteroid dehydrogenase activity) from heat-exposed males secreted less (p < 0.05) T compared with the control group when incubated without LH (basal conditions). Androstenedione secretion decreased (p < 0.05) in WA rats. Secretion of estradiol-17beta (E(2)) was higher in WR and lower in DA cells under basal conditions. Weaker responsiveness to LH was observed in WR cells. Androgen synthesis from pregnenolone by interstitial cells increased (p < 0.05) in the WA group. We concluded that heat exposure of neonatal and adult male rats caused different pituitary-testicular axis adjustments. It seemed that long-term heat exposure of neonatal rats is less deleterious concerning the activity of pituitary-testicular axis than heat acclimation of adults.

  19. Copper uptake kinetics and regulation in a marine fish after waterborne copper acclimation

    Energy Technology Data Exchange (ETDEWEB)

    Dang Fei; Zhong Huan [AMCE and Department of Biology, Hong Kong University of Science and Technology (HKUST), Clear Water Bay, Kowloon (Hong Kong); Wang Wenxiong, E-mail: wwang@ust.hk [AMCE and Department of Biology, Hong Kong University of Science and Technology (HKUST), Clear Water Bay, Kowloon (Hong Kong)

    2009-09-14

    The uptake kinetics and regulation of copper in a marine predatory fish, the black sea bream Acanthopagrus schlegeli after acclimation to waterborne Cu were examined, using radiotracer techniques. The dissolved Cu uptake followed a linear pattern during the time of exposure, and the calculated uptake rate constant was 6.24 L kg{sup -1} day{sup -1}. The efflux rate constant was 0.091 day{sup -1} following dietary uptake of Cu, and the dietary assimilation efficiency (AE) of Cu varied between 1.7% and 10.9% after the fish were fed with three types of prey (oysters, clams and brine shrimp). After the fish were acclimated at a nominal concentration of 50 {mu}g Cu L{sup -1} for 14 days, the Cu uptake rate and efflux rate constant did not change significantly, but the Cu body concentrations and metallothionein (MT) concentrations in fish tissues increased significantly. Subcellular Cu distributions were also modified. Significant MT induction was observed in response to increased Cu tissue concentrations, indicating that MT rather than the uptake kinetics may play a primary role in Cu regulation during waterborne Cu acclimation in this marine fish. Moreover, the high Cu efflux may also be important in Cu regulation during long-term exposure. Our modeling calculations indicated that dietary uptake was likely to be the main route for Cu bioaccumulation in the fish, and the relative contribution of waterborne and dietary uptake depended on the bioconcentration factor (BCF) of the prey and ingestion rate of fish.

  20. Relative crystallinity of plant biomass: studies on assembly, adaptation and acclimation.

    Directory of Open Access Journals (Sweden)

    Darby Harris

    Full Text Available Plant biomechanical design is central to cell shape, morphogenesis, reproductive performance and protection against environmental and mechanical stress. The cell wall forms the central load bearing support structure for plant design, yet a mechanistic understanding of its synthesis is incomplete. A key tool for studying the structure of cellulose polymorphs has been x-ray diffraction and fourier transform infrared spectroscopy (FTIR. Relative crystallinity index (RCI is based on the x-ray diffraction characteristics of two signature peaks and we used this technique to probe plant assembly, adaptation and acclimation. Confocal microscopy was used to visualize the dynamics of cellulose synthase in transgenic Arabidopsis plants expressing a homozygous YFP::CESA6. Assembly: RCI values for stems and roots were indistinguishable but leaves had 23.4 and 21.6% lower RCI than stems and roots respectively. Adaptation: over 3-fold variability in RCI was apparent in leaves from 35 plant species spanning Ordovician to Cretaceous periods. Within this study, RCI correlated positively with leaf geometric constraints and with mass per unit area, suggestive of allometry. Acclimation: biomass crystallinity was found to decrease under conditions of thigmomorphogenesis in Arabidopsis. Further, in etiolated pea hypocotyls, RCI values also decreased compared to plants that were grown in light, consistent with alterations in FTIR cellulose fingerprint peaks and live cell imaging experiments revealing rapid orientation of the YFP::cellulose synthase-6 array in response to light. Herein, results and technical challenges associated with the structure of the cell wall that gives rise to sample crystallinity are presented and examined with respect to adaptation, acclimation and assembly in ecosystem-level processes.

  1. The involvement of thyroid hormones and cortisol in the osmotic acclimation of Solea senegalensis.

    Science.gov (United States)

    Arjona, F J; Vargas-Chacoff, L; Martín del Río, M P; Flik, G; Mancera, J M; Klaren, P H M

    2008-02-01

    The peripheral conversion of the prohormone 3,5,3',5'-tetraiodothyronine (T4) to the biologically active 3,5,3'-triiodothyronine (T3), via enzymatic deiodination by deiodinases, is an important pathway in thyroid hormone metabolism. The aim of this study was to test if thyroid hormones and cortisol, as well as the outer ring deiodination (ORD) metabolic pathway, are involved in the osmoregulatory response of Senegalese sole (Solea senegalensis, Kaup 1858). We measured osmoregulatory and endocrine parameters in immature juveniles S. senegalensis acclimated to seawater (SW, 38 per thousand) and that were transferred and allowed to acclimate to different salinities (5 per thousand, 15 per thousand, 38 per thousand and 55 per thousand) for 17 days. An adjustment and a chronic regulatory period were identified following acclimation. The adjustment period immediately follows the transfer, and is characterized by altered plasma osmolalities. During this period, plasma cortisol levels increased while plasma free T4 (fT4) levels decreased. Both hormones levels returned to normal values on day 3 post-transfer. In the adjustment period, renal and hepatic ORD activities had increased concomitantly with the decrease in plasma fT4 levels in fishes transferred to extreme salinities (5 per thousand and 55 per thousand). In the chronic regulatory period, where plasma osmolality returned to normal values, plasma cortisol had increased, whereas plasma fT4 levels decreased in animals that were transferred to salinities other than SW. No major changes were observed in branchial ORD activity throughout the experiment. The inverse relationship between plasma cortisol and fT4 suggests an interaction between these hormones during both osmoregulatory periods while ORD pathway can be important in the short-term adjustment period.

  2. Characterization of the peripheral thyroid system of gilthead seabream acclimated to different ambient salinities.

    Science.gov (United States)

    Ruiz-Jarabo, I; Klaren, P H M; Louro, B; Martos-Sitcha, J A; Pinto, P I S; Vargas-Chacoff, L; Flik, G; Martínez-Rodríguez, G; Power, D M; Mancera, J M; Arjona, F J

    2017-01-01

    Thyroid hormones are involved in many developmental and physiological processes, including osmoregulation. The regulation of the thyroid system by environmental salinity in the euryhaline gilthead seabream (Sparus aurata) is still poorly characterized. To this end seabreams were exposed to four different environmental salinities (5, 15, 40 and 55ppt) for 14days, and plasma free thyroid hormones (fT3, fT4), outer ring deiodination and Na(+)/K(+)-ATPase activities in gills and kidney, as well as other osmoregulatory and metabolic parameters were measured. Low salinity conditions (5ppt) elicited a significant increase in fT3 (29%) and fT4 (184%) plasma concentrations compared to control animals (acclimated to 40ppt, natural salinity conditions in the Bay of Cádiz, Spain), while the amount of pituitary thyroid stimulating hormone subunit β (tshb) transcript abundance remained unchanged. In addition, plasma fT4 levels were positively correlated to renal and branchial deiodinase type 2 (dio2) mRNA expression. Gill and kidney T4-outer ring deiodination activities correlated positively with dio2 mRNA expression and the highest values were observed in fish acclimated to low salinities (5 and 15ppt). The high salinity (55ppt) exposure caused a significant increase in tshb expression (65%), but deiodinase gene expression (dio1 and dio2) and activity did not change and were similar to controls (40ppt). In conclusion, acclimation to different salinities led to changes in the peripheral regulation of thyroid hormone metabolism in seabream. Therefore, thyroid hormones are involved in the regulation of ion transport and osmoregulatory physiology in this species. The conclusions derived from this study may also allow aquaculturists to modulate thyroid metabolism in seabream by adjusting culture salinity. Copyright © 2016 Elsevier Inc. All rights reserved.

  3. Sensitivity and Acclimation of Three Canopy-Forming Seaweeds to UVB Radiation and Warming

    KAUST Repository

    Xiao, Xi

    2015-12-02

    Canopy-forming seaweeds, as primary producers and foundation species, provide key ecological services. Their responses to multiple stressors associated with climate change could therefore have important knock-on effects on the functioning of coastal ecosystems. We examined interactive effects of UVB radiation and warming on juveniles of three habitat-forming subtidal seaweeds from Western Australia–Ecklonia radiata, Scytothalia dorycarpa and Sargassum sp. Fronds were incubated for 14 days at 16–30°C with or without UVB radiation and growth, health status, photosynthetic performance, and light absorbance measured. Furthermore, we used empirical models from the metabolic theory of ecology to evaluate the sensitivity of these important seaweeds to ocean warming. Results indicated that responses to UVB and warming were species specific, with Sargassum showing highest tolerance to a broad range of temperatures. Scytothalia was most sensitive to elevated temperature based on the reduced maximum quantum yields of PSII; however, Ecklonia was most sensitive, according to the comparison of activation energy calculated from Arrhenius’ model. UVB radiation caused reduction in the growth, physiological responses and thallus health in all three species. Our findings indicate that Scytothalia was capable of acclimating in response to UVB and increasing its light absorption efficiency in the UV bands, probably by up-regulating synthesis of photoprotective compounds. The other two species did not acclimate over the two weeks of exposure to UVB. Overall, UVB and warming would severely inhibit the growth and photosynthesis of these canopy-forming seaweeds and decrease their coverage. Differences in the sensitivity and acclimation of major seaweed species to temperature and UVB may alter the balance between species in future seaweed communities under climate change.

  4. Sensitivity and Acclimation of Three Canopy-Forming Seaweeds to UVB Radiation and Warming.

    Directory of Open Access Journals (Sweden)

    Xi Xiao

    Full Text Available Canopy-forming seaweeds, as primary producers and foundation species, provide key ecological services. Their responses to multiple stressors associated with climate change could therefore have important knock-on effects on the functioning of coastal ecosystems. We examined interactive effects of UVB radiation and warming on juveniles of three habitat-forming subtidal seaweeds from Western Australia-Ecklonia radiata, Scytothalia dorycarpa and Sargassum sp. Fronds were incubated for 14 days at 16-30°C with or without UVB radiation and growth, health status, photosynthetic performance, and light absorbance measured. Furthermore, we used empirical models from the metabolic theory of ecology to evaluate the sensitivity of these important seaweeds to ocean warming. Results indicated that responses to UVB and warming were species specific, with Sargassum showing highest tolerance to a broad range of temperatures. Scytothalia was most sensitive to elevated temperature based on the reduced maximum quantum yields of PSII; however, Ecklonia was most sensitive, according to the comparison of activation energy calculated from Arrhenius' model. UVB radiation caused reduction in the growth, physiological responses and thallus health in all three species. Our findings indicate that Scytothalia was capable of acclimating in response to UVB and increasing its light absorption efficiency in the UV bands, probably by up-regulating synthesis of photoprotective compounds. The other two species did not acclimate over the two weeks of exposure to UVB. Overall, UVB and warming would severely inhibit the growth and photosynthesis of these canopy-forming seaweeds and decrease their coverage. Differences in the sensitivity and acclimation of major seaweed species to temperature and UVB may alter the balance between species in future seaweed communities under climate change.

  5. High-temperature sensitivity and its acclimation for photosynthetic electron transport reactions of desert succulents.

    Science.gov (United States)

    Chetti, M B; Nobel, P S

    1987-08-01

    Photosynthetic electron transport reactions of succulent plants from hot deserts are able to tolerate extremely high temperatures and to acclimate to seasonal increases in temperature. In this study, we report the influence of relatively long, in vivo, high-temperature treatments on electron transport reactions for two desert succulents, Agave deserti and Opuntia ficus-indica, species which can tolerate 60 degrees C. Whole chain electron transport averaged 3 degrees C more sensitive to a 1-hour high-temperature treatment than did PSII (Photosystem II) which in turn averaged 3 degrees C more sensitive than did PSI. For plants maintained at day/night air temperatures of 30 degrees C/20 degrees C, treatment at 50 degrees C caused these reactions to be inhibited an average of 39% during the first hour, an additional 31% during the next 4 hours, and 100% by 12 hours. Upon shifting the plants from 30 degrees C/20 degrees C to 45 degrees C/35 degrees C, the high temperatures where activity was inhibited 50% increased 3 degrees C to 8 degrees C for the three electron transport reactions, the half-times for acclimation averaging 5 days for A. deserti and 4 days for O. ficus-indica. For the 45 degrees C/35 degrees C plants treated at 60 degrees C for 1 hour, PSI activity was reduced by 54% for A. deserti and 36% for O. ficus-indica. Acclimation leads to a toleration of very high temperatures without substantial disruption of electron transport for these desert succulents, facilitating their survival in hot deserts. Indeed, the electron transport reactions of these species tolerate longer periods at higher temperatures than any other vascular plant so far reported.

  6. High-temperature sensitivity and its acclimation for photosynthetic electron reactions of desert succulents

    Energy Technology Data Exchange (ETDEWEB)

    Chetti, M.B.; Nobel, P.S. (Univ. of California, Los Angeles (USA))

    1987-08-01

    Photosynthetic electron reactions of succulent plants from hot deserts are able to tolerate extremely high temperatures and to acclimate to seasonal increase in temperature. In this study, we report the influence of relatively long, in vivo, high-temperature treatments on electron transport reactions for two desert succulents, Agave deserti and Opuntia ficus-indica, species which can tolerate 60{degree}C. Whole chain electron transport averaged 3{degree}C more sensitive to a 1-hour high-temperature treatment than did PSII (Photosystem II) which in turn averaged 3{degree}C more sensitive than did PSI. For plants maintained at day/night air temperatures of 30{degree}C/20{degree}C, treatment at 50{degree}C cause these reactions to be inhibited an average of 39% during the first hour, an additional 31% during the next 4 hours, and 100% by 12 hours. Upon shifting the plants from 30{degree}C/20{degree}C to 45{degree}C/35{degree}C, the high temperatures where activity was inhibited 50% increased 3{degree}C to 8{degree}C for the three electron transport reactions, the half-times for acclimation averaging 5 days for A. deserti and 4 days for O. ficus-indica. For the 45{degree}C/35{degree}C plants treated at 60{degree}C for 1 hour, PSI activity was reduced by 54% for A. deserti and 36% for O. ficus-indica. Acclimation leads to a toleration of very high temperatures without substantial disruption of electron transport for these desert succulents, facilitating their survival in hot deserts. Indeed, the electron transport reactions of these species tolerate longer periods at higher temperatures than any other vascular plants so far reported.

  7. WCS120 protein family and proteins soluble upon boiling in cold-acclimated winter wheat

    DEFF Research Database (Denmark)

    Vitamvas, P.; Saalbach, Gerhard; Prasil, I.T.

    2007-01-01

    The amount of proteins soluble upon boiling (especially WCS120 proteins) and the ability to develop frost tolerance (FT) after cold acclimation was studied in two frost-tolerant winter wheat cultivars, Mironovskaya 808 and Bezostaya 1. Protein get Not analysis, mass spectrometry (MS) and image...... analysis of total sample of proteins soluble upon boiling showed seven COR proteins in the CA samples and only three COR proteins in the NA samples of cultivar Mironovskaya 808 (MIR). In conclusion, the Level of the accumulation of WCS120, WCS66 and WCS40 distinguished our two frost-tolerant winter wheat...

  8. Stomatal acclimation to vapour pressure deficit doubles transpiration of small tree seedlings with warming

    DEFF Research Database (Denmark)

    Marchin, Renée M.; Broadhead, Alice A.; Bostic, Laura E.

    2016-01-01

    .5-1.3 kPa on transpiration and stomatal conductance (gs ) of tree seedlings in the temperate forest understory (Duke Forest, North Carolina, USA). We observed peaked responses of transpiration to VPD in all seedlings, and the optimum VPD for transpiration (Dopt ) shifted proportionally with increasing...... chamber VPD. Warming increased mean water use of Carya by 140% and Quercus by 150%, but had no significant effect on water use of Acer. Increased water use of ring-porous species was attributed to (1) higher air T and (2) stomatal acclimation to VPD resulting in higher gs and more sensitive stomata...

  9. Can lichen species of BSC acclimate to changing environments?

    Science.gov (United States)

    Williams, Laura; Colesie, Claudia; Büdel, Burkhard

    2015-04-01

    The Soil Crust INternational (SCIN) project aims to achieve improved appreciation of the importance and functioning of Biological Soil Crusts (BSC) in Europe. Four sites throughout Europe were identified for having important, yet diverse BSC communities: Gössenheim in Germany, Almeria in Spain, Öland in Sweden and Hochtor in Austria. These sites vary greatly in geographic and environmental conditions; and constitute, along with cyanobacteria, algae, bryophytes and fungi a host of green algal and cyanobacterial lichen species. Many of the lichen species occur in two-four locations, despite the climatic differences, and it has been observed that species are morphologically distinctive between sites. Lichens may be adapted to different environmental conditions by symbiosis with photobionts that are suited to the local conditions. Therefore, we may expect to find that a lichen species that can survive in diverse habitats to be less photobiont specific than species with a narrow range. In recent years it has been discovered that lichens can switch their photobiont throughout the course of their lives. Whether lichens can associate with an available photobiont and switch when a preferred photobiont becomes available is not conclusively known, or whether as habitats are affected by climate change, lichens will be able to switch to a new photobiont to survive changing conditions. A transplantation experiment of lichens between biomes was installed in each of the SCIN sites to investigate the potential of different lichen species to assimilate to a new environment. Where the same lichen species occurred in 2 or more locations samples were transplanted from their natural location to the foreign for a period of 2 years. Controls were also applied; this consisted of samples being transplanted within their own site to assess the effect of the transplantation itself. The photobionts of key species are sequenced to analyse diversity of photobiont interactions within/between the

  10. Kinetic study on fermentation from CO[sub 2] and H[sub 2] using the acclimated-methanogen in batch culture

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Z.Y.; Maekawa, Takaaki (Tsukuba Univ. (Japan). Inst. of Agricultural and Forest Engineering)

    1993-01-01

    Methane was produced from H[sub 2] and CO[sub 2] using the acclimated-mixed methanogens in a 3.71 fermentor in batch culture at pH 7.2 and 37[sup o]C. The fermentation kinetics parameter for the growth of methanogens, overall mass transfer coefficient of the reactor, and the conversion rate of H[sub 2] and CO[sub 2] to CH[sub 4] by the acclimated-mixed culture were determined. The maximum specific growth rate (mu[sub max]) and H[sub 2] specific consumption rate (q[sub max]) were found to be 0.064 (h[sup -1]) and 104.8 (mmol h[sup -1] g[sup -1]), respectively. Monod saturation constants for growth (Kp) and for inhibition (K'p) were found to be 3.54 (kPa) and 0.57 (kPa), respectively. These findings indicate that without very low dissolved H[sub 2] levels, the fermentation are carried out under [mu][sub max], and the specific uptake rate (q) was almost not affected at any dissolved H[sub 2] level in the range studied. The yield of CH[sub 4] (Yp/s) was calculated to be 0.245 (mol CH[sub 4] mol[sup -1] H[sub 2]), which is near the stoichiometric value of 0.25. DH[sub 2] was also measured using the Teflon tubing method and was in good agreement with those estimated by kinetic calculations. (author)

  11. Quantification of the decay and re-induction of heat acclimation in dry-heat following 12 and 26 days without exposure to heat stress

    NARCIS (Netherlands)

    Weller, A.S.; Linnane, D.M.; Jonkman, A.G.; Daanen, H.A.M.

    2007-01-01

    Compared with the induction of heat acclimation (HA), studies investigating the decay and re-induction of HA (RA) are relatively sparse and have yielded conflicting results. Therefore, 16 semi-nude men were acclimated to dry-heat by undertaking an exercise protocol in a hot chamber (dry-bulb tempera

  12. Effects of both ecdysone and the acclimation to low temperature, on growth and metabolic rate of juvenile freshwater crayfish Cherax quadricarinatus (Decapoda, Parastacidae

    Directory of Open Access Journals (Sweden)

    Anouk Chaulet

    2013-06-01

    Full Text Available Growth, metabolic rate, and energy reserves of Cherax quadricarinatus (von Martens, 1868 juveniles were evaluated in crayfish acclimated for 16 weeks to either 25ºC (temperature near optimum or 20ºC (marginal for the species. Additionally, the modulating effect of ecdsyone on acclimation was studied. After 12 weeks of exposure, weight gain of both experimental groups acclimated to 25ºC (control: C25, and ecdysone treated: E25 was significantly higher than that of those groups acclimated to 20ºC (C20 and E20. A total compensation in metabolic rate was seen after acclimation from 25ºC to 20ºC; for both the control group and the group treated with ecdysone. A Q10value significantly higher was only observed in the group acclimated to 20ºC and treated with ecdysone. A reduction of glycogen reserves in both hepatopancreas and muscle, as well as a lower protein content in muscle, was seen in both groups acclimated to 20ºC. Correspondingly, glycemia was always higher in these groups. Increased lipid levels were seen in the hepatopancreas of animals acclimated to 20ºC, while a higher lipid level was also observed in muscle at 20ºC, but only in ecdysone-treated crayfish.

  13. Ascorbic Acid Biosynthesis and Brackish Water Acclimation in the Euryhaline Freshwater White-Rimmed Stingray, Himantura signifer.

    Directory of Open Access Journals (Sweden)

    Samuel Z H Wong

    Full Text Available L-gulono-γ-lactone oxidase (Gulo catalyzes the last step of ascorbic acid biosynthesis, which occurs in the kidney of elasmobranchs. This study aimed to clone and sequence gulonolactone oxidase (gulo from the kidney of the euryhaline freshwater stingray, Himantura signifer, and to determine the effects of acclimation from freshwater to brackish water (salinity 20 on its renal gulo mRNA expression and Gulo activity. We also examined the effects of brackish water acclimation on concentrations of ascorbate, dehydroascorbate and ascorbate + dehydroascorbate in the kidney, brain and gill. The complete cDNA coding sequence of gulo from the kidney of H. signifer contained 1323 bp coding for 440 amino acids. The expression of gulo was kidney-specific, and renal gulo expression decreased significantly by 67% and 50% in fish acclimated to brackish water for 1 day and 6 days, respectively. There was also a significant decrease in renal Gulo activity after 6 days of acclimation to brackish water. Hence, brackish water acclimation led to a decrease in the ascorbic acid synthetic capacity in the kidney of H. signifer. However, there were significant increases in concentrations of ascorbate and ascorbate + dehydroascorbate in the gills (after 1 or 6 days, and a significant increase in the concentration of ascorbate and a significant decrease in the concentration of dehydroascorbate in the brain (after 1 day of fish acclimated to brackish water. Taken together, our results indicate that H. signifer might experience greater salinity-induced oxidative stress in freshwater than in brackish water, possibly related to its short history of freshwater invasion. These results also suggest for the first time a possible relationship between the successful invasion of the freshwater environment by some euryhaline marine elasmobranchs and the ability of these elasmobranchs to increase the capacity of ascorbic acid synthesis in response to hyposalinity stress.

  14. Ascorbic Acid Biosynthesis and Brackish Water Acclimation in the Euryhaline Freshwater White-Rimmed Stingray, Himantura signifer.

    Science.gov (United States)

    Wong, Samuel Z H; Ching, Biyun; Chng, You R; Wong, Wai P; Chew, Shit F; Ip, Yuen K

    2013-01-01

    L-gulono-γ-lactone oxidase (Gulo) catalyzes the last step of ascorbic acid biosynthesis, which occurs in the kidney of elasmobranchs. This study aimed to clone and sequence gulonolactone oxidase (gulo) from the kidney of the euryhaline freshwater stingray, Himantura signifer, and to determine the effects of acclimation from freshwater to brackish water (salinity 20) on its renal gulo mRNA expression and Gulo activity. We also examined the effects of brackish water acclimation on concentrations of ascorbate, dehydroascorbate and ascorbate + dehydroascorbate in the kidney, brain and gill. The complete cDNA coding sequence of gulo from the kidney of H. signifer contained 1323 bp coding for 440 amino acids. The expression of gulo was kidney-specific, and renal gulo expression decreased significantly by 67% and 50% in fish acclimated to brackish water for 1 day and 6 days, respectively. There was also a significant decrease in renal Gulo activity after 6 days of acclimation to brackish water. Hence, brackish water acclimation led to a decrease in the ascorbic acid synthetic capacity in the kidney of H. signifer. However, there were significant increases in concentrations of ascorbate and ascorbate + dehydroascorbate in the gills (after 1 or 6 days), and a significant increase in the concentration of ascorbate and a significant decrease in the concentration of dehydroascorbate in the brain (after 1 day) of fish acclimated to brackish water. Taken together, our results indicate that H. signifer might experience greater salinity-induced oxidative stress in freshwater than in brackish water, possibly related to its short history of freshwater invasion. These results also suggest for the first time a possible relationship between the successful invasion of the freshwater environment by some euryhaline marine elasmobranchs and the ability of these elasmobranchs to increase the capacity of ascorbic acid synthesis in response to hyposalinity stress.

  15. Effect of protective agents and previous acclimation on ethanol resistance of frozen and freeze-dried Lactobacillus plantarum strains.

    Science.gov (United States)

    Bravo-Ferrada, Bárbara Mercedes; Brizuela, Natalia; Gerbino, Esteban; Gómez-Zavaglia, Andrea; Semorile, Liliana; Tymczyszyn, E Elizabeth

    2015-12-01

    The aim of this work was to study the protective effect of sucrose, trehalose and glutamate during freezing and freeze-drying of three oenological Lactobacillus plantarum strains previously acclimated in the presence of ethanol. The efficiency of protective agents was assessed by analyses of membrane integrity and bacterial cultivability in a synthetic wine after the preservation processes. No significant differences in the cultivability, with respect to the controls cells, were observed after freezing at -80 °C and -20 °C, and pre-acclimated cells were more resistant to freeze-drying than non-acclimated ones. The results of multiparametric flow cytometry showed a significant level of membrane damage after freeze-drying in two of the three strains. The cultivability was determined after incubation in wine-like medium containing 13 or 14% v/v ethanol at 21 °C for 24 h and the results were interpreted using principal component analysis (PCA). Acclimation was the most important factor for preservation, increasing the bacterial resistance to ethanol after freezing and freeze-drying. Freeze-drying was the most drastic method of preservation, followed by freezing at -20 °C. The increase of ethanol concentration from 6 to 10% v/v in the acclimation medium improved the recovery of two of the three strains. In turn, the increase of ethanol content in the synthetic wine led to a dramatic decrease of viable cells in the three strains investigated. The results of this study indicate that a successful inoculation of dehydrated L. plantarum in wine depends not only on the use of protective agents, but also on the cell acclimation process prior to preservation, and on the ethanol content of wine.

  16. Heat acclimation responses of an ultra-endurance running group preparing for hot desert-based competition.

    Science.gov (United States)

    Costa, Ricardo J S; Crockford, Michael J; Moore, Jonathan P; Walsh, Neil P

    2014-01-01

    Heat acclimation induces adaptations that improve exercise tolerance in hot conditions. Here we report novel findings into the effects of ultra-marathon specific exercise load in increasing hot ambient conditions on indices of heat acclimation. Six male ultra-endurance runners completed a standard pre-acclimation protocol at 20°C ambient temperature (T amb), followed by a heat acclimation protocol consisting of six 2 h running exercise-heat exposures (EH) at 60% VO2max on a motorised treadmill in an environmental chamber. Three EH were performed at 30°C T amb, followed by another three EH at 35°C T amb. EH were separated by 48 h within T amb and 72 h between T amb. Nude body mass (NBM), blood and urine samples were collected pre-exercise; while NBM and urine were collected post-exercise. Rectal temperature (T re), heart rate (HR), thermal comfort rating (TCR) and rating of perceived exertion were measured pre-exercise and monitored every 5 min during exercise. Water was provided ad libitum during exercise. Data were analysed using a repeated measures and one-way analysis of variance (ANOVA), with post hoc Tukey's HSD. Significance was accepted as Pheat acclimation in all ultra-endurance runners. Further, heat acclimation responses occurred with increasing EH to 35°C T amb. Preventing exertional heat illnesses and optimising performance outcomes in ultra-endurance runners may occur with exposure to at least 2 h of exercise-heat stress on at least two occasions in the days leading up to multi-stage ultra-marathon competition in the heat.

  17. Cross-tolerance effects due to adult heat hardening, desiccation and starvation acclimation of tropical drosophilid-Zaprionus indianus.

    Science.gov (United States)

    Kalra, Bhawna; Tamang, Aditya Moktan; Parkash, Ravi

    2017-07-01

    Some insect taxa from polar or temperate habitats have shown cross-tolerance for multiple stressors but tropical insect taxa have received less attention. Accordingly, we considered adult flies of a tropical drosophilid-Zaprionus indianus for testing direct as well as cross-tolerance effects of rapid heat hardening (HH), desiccation acclimation (DA) and starvation acclimation (SA) after rearing under warmer and drier season specific simulated conditions. We observed significant direct acclimation effects of HH, DA and SA; and four cases of cross-tolerance effects but no cross-tolerance between desiccation and starvation. Cross-tolerance due to heat hardening on desiccation showed 20% higher effect than its reciprocal effect. There is greater reduction of water loss in heat hardened flies (due to increase in amount of cuticular lipids) as compared with desiccation acclimated flies. However, cross-tolerance effect of SA on heat knockdown was two times higher than its reciprocal. Heat hardened and desiccation acclimated adult flies showed substantial increase in the level of trehalose and proline while body lipids increased due to heat hardening or starvation acclimation. However, maximum increase in energy metabolites was stressor specific i.e. trehalose due to DA; proline due to HH and total body lipids due to SA. Rapid changes in energy metabolites due to heat hardening seem compensatory for possible depletion of trehalose and proline due to desiccation stress; and body lipids due to starvation stress. Thus, observed cross-tolerance effects in Z. indianus represent physiological changes to cope with multiple stressors related to warmer and drier subtropical habitats. Copyright © 2017 Elsevier Inc. All rights reserved.

  18. Exercise- and methylcholine-induced sweating responses in older and younger men: effect of heat acclimation and aerobic fitness

    Science.gov (United States)

    Inoue, Y.; Havenith, George; Kenney, W. Larry; Loomis, Joseph L.; Buskirk, Elsworth R.

    The purpose of this investigation was to examine the effects of aging and aerobic fitness on exercise- and methylcholine-induced sweating responses during heat acclimation. Five younger [Y group - age: 23+/-1 (SEM) years; maximal oxygen consumption (V.O2max): 47+/-3 ml.kg-1.min-1], four highly fit older (HO group - 63+/-3 years; 48+/-4 ml.kg-1.min-1) and five normally fit older men (NO group - 67+/-3 years; 30+/-1 ml.kg-1.min-1) who were matched for height, body mass and percentage fat, were heat acclimated by daily cycle exercise ( 35% V.O2max for 90 min) in a hot (43°C, 30% RH) environment for 8 days. The heat acclimation regimen increased performance time, lowered final rectal temperature (Tre) and percentage maximal heart rate (%HRmax), improved thermal comfort and decreased sweat sodium concentration similarly in all groups. Although total body sweating rates (M.sw) during acclimation were significantly greater in the Y and HO groups than in the NO group (Prates (m.sw) on chest, back, forearm and thigh changed in all groups by the acclimation. The HO group presented greater forearm m.sw (30-90 min) values and the Y group had greater back and thigh m.sw (early in exercise) values, compared to the other groups (PHO>NO, and on the forearm Y=HO>NO. No group differences were observed for activated sweat gland density at any site. The SGO at the respective sites increased in the post-acclimation test regardless of group (Pincrease was lower in the NO (Pexercised at the same relative exercise intensity. Furthermore, the changes induced by acclimation appear associated with an age-related decrease in V.O2max. However methylcholine-activated SGO and the magnitude of improvement of SGO with acclimation are related not only to V.O2max but also to aging, suggesting that sensitivity to cholinergic stimulation decreases with aging.

  19. Deciphering the ecophysiological traits involved during water stress acclimation and recovery of the threatened wild carnation, Dianthus inoxianus.

    Science.gov (United States)

    López-Jurado, Javier; Balao, Francisco; Mateos-Naranjo, Enrique

    2016-12-01

    Dianthus inoxianus is an endangered species endemic from a small littoral area in the SW Spain, with an unusual flowering season under the adverse conditions of dry Mediterranean summer. A greenhouse experiment was designed to assess the physiological traits involved in drought acclimation and recovery of 3-month-old plants. The evolution of plant water status, leaf gas exchange, chlorophyll fluorescence, photosynthetic pigments concentrations and a quantitative analysis of photosynthesis limitations were followed during water stress and re-watering. Our results indicated that the plant water status, Ψw and RWC, only decreased at the end of the drought period (18th day), together with the net photosynthetic rate, AN. Photosynthetic impair was mainly caused by diffusional limitations (SL and MCL) of CO2, as indicated the joint and marked decrease of gs, gm and Ci during drought period, while Vc,max did not vary. After rewatering, leaf water status recovered faster than photosynthetic one, reaching control values on day 1 after recovery, while AN, gm and Ci took 7 days. Additionally, gs showed the slowest recovery taking 15 days, but gs decrease was enough to keep Ψw and RWC at constant values throughout the experiment. Results suggest a high tolerance and recovery of D. inoxianus from severe drought periods. This drought tolerance was also reflected in the stability of its photochemical apparatus and pigments concentrations, as indicated the constant values of Fv/Fm, ФPSII and pigments concentrations through experimental period. However, prolonged drought events due to global climate change could negatively affect the physiological mechanisms of this species.

  20. A model of canopy photosynthesis incorporating protein distribution through the canopy and its acclimation to light, temperature and CO2

    Science.gov (United States)

    Johnson, Ian R.; Thornley, John H. M.; Frantz, Jonathan M.; Bugbee, Bruce

    2010-01-01

    Background and Aims The distribution of photosynthetic enzymes, or nitrogen, through the canopy affects canopy photosynthesis, as well as plant quality and nitrogen demand. Most canopy photosynthesis models assume an exponential distribution of nitrogen, or protein, through the canopy, although this is rarely consistent with experimental observation. Previous optimization schemes to derive the nitrogen distribution through the canopy generally focus on the distribution of a fixed amount of total nitrogen, which fails to account for the variation in both the actual quantity of nitrogen in response to environmental conditions and the interaction of photosynthesis and respiration at similar levels of complexity. Model A model of canopy photosynthesis is presented for C3 and C4 canopies that considers a balanced approach between photosynthesis and respiration as well as plant carbon partitioning. Protein distribution is related to irradiance in the canopy by a flexible equation for which the exponential distribution is a special case. The model is designed to be simple to parameterize for crop, pasture and ecosystem studies. The amount and distribution of protein that maximizes canopy net photosynthesis is calculated. Key Results The optimum protein distribution is not exponential, but is quite linear near the top of the canopy, which is consistent with experimental observations. The overall concentration within the canopy is dependent on environmental conditions, including the distribution of direct and diffuse components of irradiance. Conclusions The widely used exponential distribution of nitrogen or protein through the canopy is generally inappropriate. The model derives the optimum distribution with characteristics that are consistent with observation, so overcoming limitations of using the exponential distribution. Although canopies may not always operate at an optimum, optimization analysis provides valuable insight into plant acclimation to environmental

  1. Roles of sodium hydrosulfide and sodium nitroprusside as priming molecules during drought acclimation in citrus plants.

    Science.gov (United States)

    Ziogas, Vasileios; Tanou, Georgia; Belghazi, Maya; Filippou, Panagiota; Fotopoulos, Vasileios; Grigorios, Diamantidis; Molassiotis, Athanassios

    2015-11-01

    Emerging evidence suggests that the gaseous molecules hydrogen sulfide (H2S) and nitric oxide (NO) enhances plant acclimation to stress; however, the underlying mechanism remains unclear. In this work, we explored if pretreatment of citrus roots with NaHS (a H2S donor) or sodium nitroprusside (SNP, a NO donor) for 2 days (d) could elicit long-lasting priming effects to subsequent exposure to PEG-associated drought stress for 21 d following a 5 d acclimation period. Detailed physiological study documented that both pretreatments primed plants against drought stress. Analysis of the level of nitrite, NOx, S-nitrosoglutahione reductase, Tyr-nitration and S-nitrosylation along with the expression of genes involved in NO-generation suggested that the nitrosative status of leaves and roots was altered by NaHS and SNP. Using a proteomic approach we characterized S-nitrosylated proteins in citrus leaves exposed to chemical treatments, including well known and novel S-nitrosylated targets. Mass spectrometry analysis also enabled the identification of 42 differentially expressed proteins in PEG alone-treated plants. Several PEG-responsive proteins were down-regulated, especially photosynthetic proteins. Finally, the identification of specific proteins that were regulated by NaHS and SNP under PEG conditions provides novel insight into long-term drought priming in plants and in a fruit crop such as citrus in particular.

  2. Thermal tolerance and preferred temperature range of juvenile meagre acclimated to four temperatures.

    Science.gov (United States)

    Kır, Mehmet; Sunar, Murat Can; Altındağ, Barış Can

    2017-04-01

    The present study reports the temperature tolerance, estimated using dynamic and static methodologies, and preferred temperature range, based on oxygen consumption rate (OCR), of juvenile meagre (Argyrosomus regius) (Asso, 1801) (3.4±0.9g) after 30 days of acclimation at 18, 22, 26 and 30°C. Meagre has dynamic and static thermal tolerance zones of 551°C(2) and 460°C(2), respectively and is a low resistance fish species, with a resistance zone area of 87°C(2). The OCR of juvenile meagre at the above acclimation temperatures was 370, 410, 618 and 642mgh(-1)kg(-)(1), respectively, and is significantly different (P<0.0001, n=20). The fact that OCR increases by rising temperatures and gradually decreases after 26°C indicates that the preferred temperature range of juvenile meagre is between 26 and 30°C. Our study suggests that meagre is unable to respond to low and high temperature variation in aquaculture facilities or its natural habitats. Copyright © 2017 Elsevier Ltd. All rights reserved.

  3. The responses of tropical forest species to global climate change: acclimate, adapt, migrate, or go extinct?

    Directory of Open Access Journals (Sweden)

    Brian Machovina

    2012-06-01

    Full Text Available In the face of ongoing and future climate change, species must acclimate, adapt or shift their geographic distributions (i.e., "migrate" in order to avoid habitat loss and eventual extinction. Perhaps nowhere are the challenges posed by climate change more poignant and daunting than in tropical forests, which harbor the majority of Earth’s species and are facing especially rapid rates of climate change relative to current spatial or temporal variability. Due to the rapid changes in climate predicted for the tropics, coupled with the apparently low capacities of tropical tree species to either acclimate or adapt to sustained changes in environmental conditions, it is believed that the greatest hope for avoiding the loss of biodiversity in tropical forest is species migrations. This is supported by the fact that topical forests responded to historic changes in climate (e.g., post glacial warming through distributional shifts. However, a great deal of uncertainty remains as to if tropical plant and tree species can migrate, and if so, if they can migrate at the rates required to keep pace with accelerating changes in multiple climatic factors in conjunction with ongoing deforestation and other anthropogenic disturbances. In order to resolve this uncertainty, as will be required to predict, and eventually mitigate, the impacts of global climate change on tropical and global biodiversity, more basic data is required on the distributions and ecologies of tens of thousands of plants species in combination with more directed studies and large-scale experimental manipulations.

  4. Dietary fatty acid metabolism of brown adipose tissue in cold-acclimated men

    Science.gov (United States)

    Blondin, Denis P.; Tingelstad, Hans C.; Noll, Christophe; Frisch, Frédérique; Phoenix, Serge; Guérin, Brigitte; Turcotte, Éric E; Richard, Denis; Haman, François; Carpentier, André C.

    2017-01-01

    In rodents, brown adipose tissue (BAT) plays an important role in producing heat to defend against the cold and can metabolize large amounts of dietary fatty acids (DFA). The role of BAT in DFA metabolism in humans is unknown. Here we show that mild cold stimulation (18 °C) results in a significantly greater fractional DFA extraction by BAT relative to skeletal muscle and white adipose tissue in non-cold-acclimated men given a standard liquid meal containing the long-chain fatty acid PET tracer, 14(R,S)-[18F]-fluoro-6-thia-heptadecanoic acid (18FTHA). However, the net contribution of BAT to systemic DFA clearance is comparatively small. Despite a 4-week cold acclimation increasing BAT oxidative metabolism 2.6-fold, BAT DFA uptake does not increase further. These findings show that cold-stimulated BAT can contribute to the clearance of DFA from circulation but its contribution is not as significant as the heart, liver, skeletal muscles or white adipose tissues. PMID:28134339

  5. Light acclimation of leaf gas exchange in two Tunisian cork oak populations from contrasting environmental conditions

    Directory of Open Access Journals (Sweden)

    Rzigui T

    2015-10-01

    Full Text Available Due to diverse environmental conditions, Mediterranean plant populations are exposed to a range of selective pressures that may lead to phenotypic plasticity and local adaptation. We examined the effect of light acclimation on photosynthetic capacity in two Quercus suber (L. populations that are native to different ecological conditions. Low-light adapted seedlings from both populations were exposed to three light treatments: full sunlight (HL, medium light (ML, 43% sunlight and low light (LL, 15% sunlight for one month. Photosynthetic performance was monitored by measuring leaf gas exchange and chlorophyll fluorescence parameters. The light environment influences light-saturated carbon assimilation (Amax in the leaves of the population inhabiting the hot and dry region (from Gaafour. In contrast, there was no significant difference in Amax between leaves grown in high light and low light from Feija (the population native to a cold and humid climate, which suggests an inability of the Feija population to adjust its photosynthesis to respond to higher irradiance. The inability of the Feija population to adjust its photosynthesis did not result from a light acclimation failure in terms of chlorophyll content and ratio compared with the Gaafour population. Instead, it seems to be the consequence of lower stomatal conductance in the Feija population at HL compared to Gaafour.

  6. Rootstock control of scion transpiration and its acclimation to water deficit are controlled by different genes.

    Science.gov (United States)

    Marguerit, Elisa; Brendel, Oliver; Lebon, Eric; Van Leeuwen, Cornelis; Ollat, Nathalie

    2012-04-01

    The stomatal control of transpiration is one of the major strategies by which plants cope with water stress. Here, we investigated the genetic architecture of the rootstock control of scion transpiration-related traits over a period of 3 yr. The rootstocks studied were full sibs from a controlled interspecific cross (Vitis vinifera cv. Cabernet Sauvignon × Vitis riparia cv. Gloire de Montpellier), onto which we grafted a single scion genotype. After 10 d without stress, the water supply was progressively limited over a period of 10 d, and a stable water deficit was then applied for 15 d. Transpiration rate was estimated daily and a mathematical curve was fitted to its response to water deficit intensity. We also determined δ(13) C values in leaves, transpiration efficiency and water extraction capacity. These traits were then analysed in a multienvironment (year and water status) quantitative trait locus (QTL) analysis. Quantitative trait loci, independent of year and water status, were detected for each trait. One genomic region was specifically implicated in the acclimation of scion transpiration induced by the rootstock. The QTLs identified colocalized with genes involved in water deficit responses, such as those relating to ABA and hydraulic regulation. Scion transpiration rate and its acclimation to water deficit are thus controlled genetically by the rootstock, through different genetic architectures. © 2012 INRA. New Phytologist © 2012 New Phytologist Trust.

  7. Coordinated Regulations of mRNA Synthesis and Decay during Cold Acclimation in Arabidopsis Cells.

    KAUST Repository

    Arae, Toshihiro

    2017-04-18

    Plants possess a cold acclimation system to acquire freezing tolerance through pre-exposure to non-freezing low temperatures. The transcriptional cascade of C-repeat binding factors (CBFs)/dehydration response element-binding factors (DREBs) is considered a major transcriptional regulatory pathway during cold acclimation. However, little is known regarding the functional significance of mRNA stability regulation in the response of gene expression to cold stress. The actual level of individual mRNAs is determined by a balance between mRNA synthesis and degradation. Therefore, it is important to assess the regulatory steps to increase our understanding of gene regulation. Here, we analyzed temporal changes in mRNA amounts and half-lives in response to cold stress in Arabidopsis cell cultures based on genome-wide analysis. In this mRNA decay array method, mRNA half-life measurements and microarray analyses were combined. In addition, temporal changes in the integrated value of transcription rates were estimated from the above two parameters using a mathematical approach. Our results showed that several cold-responsive genes, including Cold-regulated 15a, were relatively destabilized, whereas the mRNA amounts were increased during cold treatment by accelerating the transcription rate to overcome the destabilization. Considering the kinetics of mRNA synthesis and degradation, this apparently contradictory result supports that mRNA destabilization is advantageous for the swift increase in CBF-responsive genes in response to cold stress.

  8. Nutrient scavenging and energy management: acclimation responses in nitrogen and sulfur deprived Chlamydomonas.

    Science.gov (United States)

    Saroussi, Shai; Sanz-Luque, Emanuel; Kim, Rick G; Grossman, Arthur R

    2017-10-01

    Photosynthetic organisms have evolved to modulate their metabolism to accommodate the highly dynamic light and nutrient conditions in nature. In this review we discuss ways in which the green alga Chlamydomonas reinhardtii acclimates to nitrogen and sulfur deprivation, conditions that would limit the anabolic use of excitation energy because of a markedly reduced capacity for cell growth and division. Major aspects of this acclimation process are stringently regulated and involve scavenging the limited nutrient from internal and external sources, and the redirection of fixed carbon toward energy storage (e.g. starch, oil). However, photosynthetic organisms have also evolved mechanisms to dissipate excess absorbed light energy, and to eliminate potentially dangerous energetic electrons through the reduction of O2 and H(+) to H2O; this reduction can occur both through photosynthetic electron transport (e.g. Mehler reaction, chlororespiration) and mitochondrial respiration. Furthermore, algal cells likely exploit other energy management pathways that are currently not linked to nutrient limitation responses or that remain to be identified. Copyright © 2017 Elsevier Ltd. All rights reserved.

  9. Assessment of Barotrauma from Rapid Decompression of Depth-Acclimated Juvenile Chinook Salmon Bearing Radiotelemetry Transmitters

    Energy Technology Data Exchange (ETDEWEB)

    Brown, Richard S.; Carlson, Thomas J.; Welch, Abigail E.; Stephenson, John R.; Abernethy, Cary S.; Ebberts, Blaine D.; Langeslay, Mike; Ahmann, Martin L.; Feil, Daniel H.; Skalski, J. R.; Townsend, Richard L.

    2009-11-01

    This study investigated the mortality of and injury to juvenile Chinook salmon Oncorhynchus tshawytscha exposed to simulated pressure changes associated with passage through a large Kaplan hydropower turbine. Mortality and injury varied depending on whether a fish was carrying a transmitter, the method of transmitter implantation, the depth of acclimation, and the size of the fish. Juvenile Chinook salmon implanted with radio transmitters were more likely than those without to die or sustain injuries during simulated turbine passage. Gastric transmitter implantation resulted in higher rates of injury and mortality than surgical implantation. Mortality and injury increased with increasing pressure of acclimation. Injuries were more common in subyearling fish than in yearling fish. Gas emboli in the gills and internal hemorrhaging were the major causes of mortality. Rupture of the swim bladder and emphysema in the fins were also common. This research makes clear that the exposure of juvenile Chinook salmon bearing radiotelemetry transmitters to simulated turbine pressures with a nadir of 8-19 kPa can result in barotrauma, leading to immediate or delayed mortality. The study also identified sublethal barotrauma injuries that may increase susceptibility to predation. These findings have significant implications for many studies that use telemetry devices to estimate the survival and behavior of juvenile salmon as they pass through large Kaplan turbines typical of those within the Columbia River hydropower system. Our results indicate that estimates of turbine passage survival for juvenile Chinook salmon obtained with radiotelemetry devices may be negatively biased.

  10. Adaptive and acclimative responses of cyanobacteria to far-red light.

    Science.gov (United States)

    Gan, Fei; Bryant, Donald A

    2015-10-01

    Cyanobacteria use three major photosynthetic complexes, photosystem (PS) I, PS II and phycobilisomes, to harvest and convert sunlight into chemical energy. Until recently, it was generally thought that cyanobacteria only used light between 400 nm and 700 nm to perform photosynthesis. However, the discovery of chlorophyll (Chl) d in Acaryochloris marina and Chl f in Halomicronema hongdechloris showed that some cyanobacteria could utilize far-red light. The synthesis of Chl f (and Chl d) is part of an extensive acclimation process, far-red light photoacclimation (FaRLiP), which occurs in many cyanobacteria. Organisms performing FaRLiP contain a conserved set of 17 genes encoding paralogous subunits of the three major photosynthetic complexes. Far-red light photoacclimation leads to substantial remodelling of the photosynthetic apparatus and other changes in cellular metabolism through extensive changes in transcription. Far-red light photoacclimation appears to be controlled by a red/far-red photoreceptor, RfpA, as well as two response regulators (RfpB and RfpC), one of which is a DNA-binding protein. The remodelled photosynthetic complexes, including novel phycobiliproteins, absorb light above 700 nm and enable cells to grow in far-red light. A much simpler acclimation response, low-light photoacclimation (LoLiP), occurs in some cyanobacteria that contain the apcD4-apcB3-isiX cluster, which allows cells to grow under low light conditions.

  11. THE RELIABILITY OF ADOLESCENT THERMOREGULATORY RESPONSES DURING A HEAT ACCLIMATION PROTOCOL

    Directory of Open Access Journals (Sweden)

    Craig A. Williams

    2009-12-01

    Full Text Available This study investigated the between trial variation of thermoregulatory measures during a heat acclimation protocol. Eight 14-16 y old boys completed three bouts of 20-min cycling at 45 % peak VO2 in a hot environment (35.1 ± 1.2 °C and 46. 4 ± 1.0 % relative humidity on two occasions separated by a minimum of 24 h. Reliability was assessed through analysis of within-subject variation, the change in the mean, and retest correlation for measurements of aural temperature (Tau, mean skin temperature (Tsk, heart rate (HR and oxygen uptake (VO2. Between trial differences were low for Tau, Tskbout1, Tskbout2and3 and HR with coefficients of variation 0.6 %, 1.5 %, 0.5 % and 4.0 %, respectively. The results demonstrate good reliability that will allow future investigators to precisely determine the extent of heat acclimation protocols in relation to the measurement error

  12. Body mass, Thermogenesis and energy metabolism in Tupaia belangeri during cold acclimation

    Directory of Open Access Journals (Sweden)

    Wan-long Zhu

    2012-05-01

    Full Text Available In order to study the relationship between energy strategies and environmental temperature, basal metabolic rate (BMR, nonshivering thermogenesis (NST, the total protein contents, mitochondrial protein contents, state and state respiratory ability, cytochrome C oxidase activity Ⅲ Ⅳ of liver, heart, diaphragm, gastrocnemius and brown adipose tissue (BAT, serum leptin level and serum thyroid hormone levels were measured in tree shrews (Tupaia belangeri during cold exposure (5±1oC for 1 day, 7 days,14days,21 days. The results showed that body mass increased, BMR and NST increased, the change of liver mitochondrial protein content was more acutely than total protein. The mitochondrial protein content of heart and BAT were significantly increased during cold-exposed, however the skeletal muscle more moderate reaction. The state Ⅲ and state Ⅳ mitochondrial respiration of these tissues were enhanced significantly than the control. The cytochrome C oxidase activity with cold acclimation also significantly increased except the gastrocnemius. Liver, muscle, BAT, heart and other organs were concerned with thermoregulation during the thermal regulation process above cold-exposed. There is a negative correlation between leptin level and body mass. These results suggested that T. belangeri enhanced thermogenic capacity during cold acclimation, and leptin participated in the regulation of energy balance and body weight in T. belangeri.

  13. Thermoregulation in cold- and noncold-acclimated rats cold exposed in hypergravic fields

    Science.gov (United States)

    Horowitz, J. M.; Horwitz, B. A.; Monson, C. B.

    1983-01-01

    The effect of hypergravity on thermoregulation processes is investigated experimentally in rats. Hooded male Long-Evans rats were kept for 6 weeks at 5 or 23 C (cold-acclimated and noncold-acclimated groups, CA and NCA) prior to testing. One test protocol comprised sequential 1-h exposures to 23 C at 1 G, 23 C at 3 G (in a 2.1-m radius centrifuge; -Gx), 8 C at 3 G, 8 C at 1 G, and finally 23 C at 1 G, with continuous measurement of the oxygen consumption. In a second protocol, restrained rats were exposed to 23 C at 1 G, 23 C at 3 G, and 10 C at 3 G, and core temperature changes were monitored. The results are presented in graphs and a table. Oxygen consumption doubled in both CA and NCA rats on exposure to cold at 1 G, but at 3 G NCA consumption decreased while CA consumption remained high. The CA rats were also more able to maintain core temperature at 3 G than the NCA rats. These differences are attributed to the nonshivering thermogenic processes developed in CA rats, which appear to be unaffected by hypergravity.

  14. Thermoregulatory responses during thermal acclimation in pigs divergently selected for residual feed intake

    Science.gov (United States)

    Campos, Paulo Henrique Reis Furtado; Noblet, Jean; Jaguelin-Peyraud, Yolande; Gilbert, Hélène; Mormède, Pierre; de Oliveira Donzele, Rita Flavia Miranda; Donzele, Juarez Lopes; Renaudeau, David

    2014-09-01

    The objective of this study was to evaluate the performance and thermoregulatory responses during acclimation to high ambient temperature (Ta) of pigs from two lines selected for high (RFI+) or low (RFI-) residual feed intake with the hypothesis that RFI- pigs producing less heat would better tolerate high Ta. Pigs (50 kg initial body weight; 17 per line among which 10 of them were catheterized) were individually housed in a climatic-controlled room where Ta was maintained at 24.2 ± 0.4 °C during 7 days and thereafter at 30.4 ± 0.7 °C during 14 days. Irrespective of Ta, RFI- pigs had lower feed intake (ADFI) and similar average daily gain (ADG) than RFI+ pigs. Whatever the line, ADFI, ADG, and feed efficiency decreased with increased Ta. Overall, the Ta increase resulted in an increase in rectal temperature (RT), skin temperature (ST), and respiratory rate (RR) within the first 24-48 h and, subsequently, in a decrease followed by stabilization. The RT decrease during acclimation occurred 24 h earlier in RFI- pigs than in RFI+. Thyroid hormones and cortisol decreased at high Ta and it was similar in both lines. Based on performance and RT, ST, and RR responses, it seems that selection for low RFI tends to ameliorate pigs' tolerance to high Ta. Nevertheless, this selection does not induce significant differences between lines in endocrine and metabolite responses during thermal stress.

  15. Plant acclimation impacts carbon allocation to isoprene emissions: evidence from past to future CO2 levels

    Science.gov (United States)

    de Boer, Hugo J.; van der Laan, Annick; Dekker, Stefan C.; Holzinger, Rupert

    2016-04-01

    Isoprene (C5H8) is produced in plant leaves as a side product of photosynthesis, whereby approximately 0.1-2.0% of the photosynthetic carbon uptake is released back into the atmosphere via isoprene emissions. Isoprene biosynthesis is thought to alleviate oxidative stress, specifically in warm, dry and high-light environments. Moreover, isoprene biosynthesis is influenced by atmospheric CO2 concentrations in the short term (weeks) via acclimation in photosynthetic biochemistry. In order to understand the effects of CO2-induced climate change on carbon allocation in plants it is therefore important to quantify how isoprene biosynthesis and emissions are effected by both short-term responses and long-term acclimation to rising atmospheric CO2 levels. A promising development for modelling CO2-induced changes in isoprene emissions is the Leaf-Energetic-Status model (referred to as LES-model hereafter, see Harrison et al., 2013 and Morfopoulos et al., 2014). This model simulates isoprene emissions based on the hypothesis that isoprene biosynthesis depends on the imbalance between the photosynthetic electron supply of reducing power and the electron demands of carbon fixation. In addition to environmental conditions, this imbalance is determined by the photosynthetic electron transport capacity (Jmax) and the maximum carboxylation capacity of Rubisco (V cmax). Here we compare predictions of the LES-model with observed isoprene emission responses of Quercus robur (pedunculate oak) specimen that acclimated to CO2 levels representative of the last glacial, the present and the end of this century (200, 400 and 800 ppm, respectively) for two growing seasons. Plants were grown in walk-in growth chambers with tight control of light, temperature, humidity and CO2 concentrations. Photosynthetic biochemical parameters V cmax and Jmax were determined with a Licor LI-6400XT photosynthesis system. The relationship between photosynthesis and isoprene emissions was measured by coupling

  16. Differences in acclimation potential of photosynthesis in seven isolates of the tropical to warm temperate macrophyte Valonia utricularis (Chlorophyta)

    NARCIS (Netherlands)

    Eggert, Anja; Visser, Ronald J. W.; Van Hasselt, Philip R.; Breeman, Anneke M.

    2006-01-01

    The potential to acclimate photosynthesis to sub- and supra-optimal temperatures was investigated in seven isolates of Valonia utricularis (Roth) C. Agardh, a green macrophyte with a tropical to warm-temperate distribution. Photosynthesis-light response curves were obtained by measuring chlorophyll

  17. Effect of operational strategies on activated sludge's acclimation to phenol, subsequent aerobic granulation, and accumulation of polyhydoxyalkanoates.

    Science.gov (United States)

    Wosman, Afrida; Lu, Yuhao; Sun, Supu; Liu, Xiang; Wan, Chunli; Zhang, Yi; Lee, Duu-Jong; Tay, JooHwa

    2016-11-05

    Aerobic granules, a relative novel form of microbial aggregate, are capable of degrading many toxic organic pollutants. Appropriate strategy is needed to acclimate seed sludge to the toxic compounds for successful granulation. In this study, two distinct strategies, i.e. mixed or single carbon sources, were experimented to obtain phenol-acclimated sludge. Their effects on reactor performance, biomass characteristics, microbial population and the granulation process were analyzed. Sludge fed with phenol alone exhibited faster acclimation and earlier appearance of granules, but possibly lower microbial diversity and reactor stability. Using a mixture of acetate and phenol in the acclimation stage, on the other hand, led to a reactor with slower phenol degradation and granulation, but eventual formation of strong and stable aerobic granules. In addition, the content of intracellular polyhydoxyakanoates (PHA) was also monitored, and significant accumulation was observed during the pre-granulation stage, where PHA >50% of dry weight was observed in both reactors. Copyright © 2016 Elsevier B.V. All rights reserved.

  18. Molecular and Photosynthetic Responses to Prolonged Darkness and Subsequent Acclimation to Re-Illumination in the Diatom Phaeodactylum tricornutum

    DEFF Research Database (Denmark)

    Nymark, Marianne; Valle, Kristi Collier; Hancke, Kasper

    2013-01-01

    and immediately utilize the available energy in photosynthesis and growth. We have investigated both the response to prolonged darkness and the re-acclimation to moderate intensity white irradiance (E = 100 µmol m−2 s−1) in the diatom Phaeodactylum tricornutum, using an integrated approach involving global...

  19. Acclimation of foliar respiration and photosynthesis in response to experimental warming in a temperate steppe in northern China.

    Directory of Open Access Journals (Sweden)

    Yonggang Chi

    Full Text Available BACKGROUND: Thermal acclimation of foliar respiration and photosynthesis is critical for projection of changes in carbon exchange of terrestrial ecosystems under global warming. METHODOLOGY/PRINCIPAL FINDINGS: A field manipulative experiment was conducted to elevate foliar temperature (Tleaf by 2.07°C in a temperate steppe in northern China. Rd/Tleaf curves (responses of dark respiration to Tleaf, An/Tleaf curves (responses of light-saturated net CO2 assimilation rates to Tleaf, responses of biochemical limitations and diffusion limitations in gross CO2 assimilation rates (Ag to Tleaf, and foliar nitrogen (N concentration in Stipa krylovii Roshev. were measured in 2010 (a dry year and 2011 (a wet year. Significant thermal acclimation of Rd to 6-year experimental warming was found. However, An had a limited ability to acclimate to a warmer climate regime. Thermal acclimation of Rd was associated with not only the direct effects of warming, but also the changes in foliar N concentration induced by warming. CONCLUSIONS/SIGNIFICANCE: Warming decreased the temperature sensitivity (Q10 of the response of Rd/Ag ratio to Tleaf. Our findings may have important implications for improving ecosystem models in simulating carbon cycles and advancing understanding on the interactions between climate change and ecosystem functions.

  20. Influence of acclimation and exposure temperature on the acute toxicity of cadmium to the freshwater snail Potamopyrgus antipodarum (Hydrobiidae)

    Energy Technology Data Exchange (ETDEWEB)

    Moeller, V.; Forbes, V.E.; Depledge, M.H. (Odense Univ. (Denmark). Ecotoxicology Group)

    1994-09-01

    Forty-eight-hour acute toxicity tests were performed to determine the influence of acclimation temperature (5, 15, and 20 C) and exposure temperature (5, 15, and 20 C) on the toxicity of cadmium to the freshwater gastropod Potamopyrgus antipodarum. Mortality varied with cadmium concentration and treatment conditions, but did not conform to conventional sigmoid concentration-response relationships. Because the shapes of the concentration-response curves were treatment dependent, a nontraditional approach for data analysis was employed. Regardless of acclimation temperature, mortality increased with increasing exposure temperature, and at all exposure temperatures snails acclimated at 15 C were most susceptible to cadmium toxicity. Estimated LC50 values were within 1 to 4 mg Cd/L. Although the shapes of the concentration-response curves were different for each treatment, the slopes were generally quite steep, indicating a uniform response for the whole population. At a given Cd concentration, acclimation temperature and exposure temperature accounted for 57 and 40%, respectively, of the variation in mortality, and LC50s changed by a factor of four. The results indicate that changes in environmental variables can alter both the degree of response and the response distribution of a population, and that past as well as prevailing environmental conditions can influence organismic responses to toxicants.

  1. Fructan accumulation and transcription of candidate genes during cold acclimation in three varieties of Poa pratensis

    DEFF Research Database (Denmark)

    Rao, R Shyama Prasad; Andersen, Jeppe Reitan; Dionisio, Giuseppe

    2011-01-01

    Poa pratensis, a type species for the grass family (Poaceae), is an important cool season grass that accumulates fructans as a polysaccharide reserve. We studied fructan contents and expression of candidate fructan metabolism genes during cold acclimation in three varieties of P. pratensis adapte...

  2. Cardiac molecular-acclimation mechanisms in response to swimming-induced exercise in Atlantic salmon.

    Directory of Open Access Journals (Sweden)

    Vicente Castro

    Full Text Available Cardiac muscle is a principal target organ for exercise-induced acclimation mechanisms in fish and mammals, given that sustained aerobic exercise training improves cardiac output. Yet, the molecular mechanisms underlying such cardiac acclimation have been scarcely investigated in teleosts. Consequently, we studied mechanisms related to cardiac growth, contractility, vascularization, energy metabolism and myokine production in Atlantic salmon pre-smolts resulting from 10 weeks exercise-training at three different swimming intensities: 0.32 (control, 0.65 (medium intensity and 1.31 (high intensity body lengths s(-1. Cardiac responses were characterized using growth, immunofluorescence and qPCR analysis of a large number of target genes encoding proteins with significant and well-characterized function. The overall stimulatory effect of exercise on cardiac muscle was dependent on training intensity, with changes elicited by high intensity training being of greater magnitude than either medium intensity or control. Higher protein levels of PCNA were indicative of cardiac growth being driven by cardiomyocyte hyperplasia, while elevated cardiac mRNA levels of MEF2C, GATA4 and ACTA1 suggested cardiomyocyte hypertrophy. In addition, up-regulation of EC coupling-related genes suggested that exercised hearts may have improved contractile function, while higher mRNA levels of EPO and VEGF were suggestive of a more efficient oxygen supply network. Furthermore, higher mRNA levels of PPARα, PGC1α and CPT1 all suggested a higher capacity for lipid oxidation, which along with a significant enlargement of mitochondrial size in cardiac myocytes of the compact layer of fish exercised at high intensity, suggested an enhanced energetic support system. Training also elevated transcription of a set of myokines and other gene products related to the inflammatory process, such as TNFα, NFκB, COX2, IL1RA and TNF decoy receptor. This study provides the first

  3. Infective Juveniles of the Entomopathogenic Nematode, Steinernema feltiae Produce Cryoprotectants in Response to Freezing and Cold Acclimation.

    Science.gov (United States)

    Ali, Farman; Wharton, David A

    2015-01-01

    Steinernema feltiae is a moderately freeze-tolerant entomopathogenic nematode which survives intracellular freezing. We have detected by gas chromatography that infective juveniles of S. feltiae produce cryoprotectants in response to cold acclimation and to freezing. Since the survival of this nematode varies with temperature, we analyzed their cryoprotectant profiles under different acclimation and freezing regimes. The principal cryoprotectants detected were trehalose and glycerol with glucose being the minor component. The amount of cryoprotectants varied with the temperature and duration of exposure. Trehalose was accumulated in higher concentrations when nematodes were acclimated at 5°C for two weeks whereas glycerol level decreased from that of the non-acclimated controls. Nematodes were seeded with a small ice crystal and held at -1°C, a regime that does not produce freezing of the nematodes but their bodies lose water to the surrounding ice (cryoprotective dehydration). This increased the levels of both trehalose and glycerol, with glycerol reaching a higher concentration than trehalose. Nematodes frozen at -3°C, a regime that produces freezing of the nematodes and results in intracellular ice formation, had elevated glycerol levels while trehalose levels did not change. Steinernema feltiae thus has two strategies of cryoprotectant accumulation: one is an acclimation response to low temperature when the body fluids are in a cooled or supercooled state and the infective juveniles produce trehalose before freezing. During this process a portion of the glycerol is converted to trehalose. The second strategy is a rapid response to freezing which induces the production of glycerol but trehalose levels do not change. These low molecular weight compounds are surmised to act as cryoprotectants for this species and to play an important role in its freezing tolerance.

  4. Chromatic acclimation and population dynamics of green sulfur bacteria grown with spectrally tailored light

    CERN Document Server

    Saikin, Semion K; Huh, Joonsuk; Hannout, Moataz; Wang, Yaya; Zare, Farrokh; Aspuru-Guzik, Alan; Tang, Joseph Kuo-Hsiang

    2014-01-01

    Living organisms have to adjust to their surrounding in order to survive in stressful conditions. We study this mechanism in one of most primitive creatures - photosynthetic green sulfur bacteria. These bacteria absorb photons very efficiently using the chlorosome antenna complexes and perform photosynthesis in extreme low-light environments. How the chlorosomes in green sulfur bacteria are acclimated to the stressful light conditions, for instance, if the spectrum of light is not optimal for absorption, is unknown. Studying Chlorobaculum tepidum cultures with far-red to near-infrared light-emitting diodes, we found that these bacteria react to changes in energy flow by regulating the amount of light-absorbing pigments and the size of the chlorosomes. Surprisingly, our results indicate that the bacteria can survive in near-infrared lights capturing low-frequency photons by the intermediate units of the light-harvesting complex. The latter strategy may be used by the species recently found near hydrothermal ve...

  5. Cortisol regulates nitric oxide synthase in freshwater and seawater acclimated rainbow trout, Oncorhynchus mykiss

    DEFF Research Database (Denmark)

    Gerber, Lucie; Madsen, Steffen S; Jensen, Frank B

    2017-01-01

    Cortisol and nitric oxide (NO) are regulators of ion transport and metabolic functions in fish. In the gill, they show opposite effects on Na(+)/K(+)-ATPase (NKA) activity: cortisol stimulates NKA activity while NO inhibits NKA activity. We hypothesized that cortisol may impact NO production...... in osmoregulatory tissues by regulating NO synthase (NOS) expression. We evaluated the influence of cortisol treatment on mRNA expression of Nos1 and Nos2 in gill, kidney and middle intestine of both freshwater (FW) and seawater (SW) acclimated rainbow trout and found both tissue- and salinity-dependent effects....... Nos2 expression was down-regulated in the gill by cortisol injection in both FW and SW trout. This was substantiated by incubating gill tissue with cortisol ex vivo. Similarly, cortisol injection significantly down-regulated Nos2 expression in kidney of SW fish but not in FW fish. In the middle...

  6. A Preliminary Assessment of Barotrauma Injuries and Acclimation Studies for Three Fish Species

    Energy Technology Data Exchange (ETDEWEB)

    Brown, Richard S. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Walker, Ricardo W. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Stephenson, John R. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States)

    2015-12-15

    Fish that pass hydro structures either through turbine passage, deep spill, or other deep pathways can experience rapid decreases in pressure that can result in barotrauma. In addition to morphology and physiology of the fish’s swim bladder, the severity of barotrauma is directly related to the volume of undissolved gas in fish prior to rapid decompression and the lowest pressure the fish experience as they pass hydro structures (termed the “nadir”). The volume of undissolved gas in fish is influenced by the depth of acclimation (the pressure at which the fish is neutrally buoyant); therefore, determining the depth where fish are neutrally buoyant is a critical precursor to determining the relationship between pressure changes and injury or mortality.

  7. Fructan metabolism and changes in fructan composition during cold acclimation in perennial ryegrass

    DEFF Research Database (Denmark)

    Abeynayake, Shamila; Etzerodt, Thomas; Jonavičienė, Kristina;

    2015-01-01

    biomass (top) and the roots, and the transcription of candidate genes involved in fructan metabolism during cold acclimation in perennial ryegrass variety ‘Veyo’ and ecotype ‘Falster’ from distinct geographical origins. We observed changes in fructan composition and induction of low-DP fructans......Perennial ryegrass (Lolium perenne L.) produces high levels of fructans as a mixture of oligomers with different degrees of polymerization (DP). The present study describes the analysis of the compositional changes in the full spectrum of fructan oligomers, fructan distribution between above ground....... The ecotype ‘Falster’, adapted to cold climates, increased total fructan content and produced more fructans (DP˃7) in the roots than the variety ‘Veyo’, adapted to warmer climates suggesting that accumulation of fructans in roots, especially the high-DP fructans as an adaptive trait for plant recovery after...

  8. CO2 acclimation impacts leaf isoprene emissions: evidence from past to future CO2 levels

    Science.gov (United States)

    de Boer, Hugo; van der Laan, Annick; Dekker, Stefan; Holzinger, Rupert

    2017-04-01

    Isoprene is emitted by many plant species as a side-product of photosynthesis. Once in the atmosphere, isoprene exhibits climate forcing through various feedback mechanisms. In order to quantify the climate feedbacks of biogenic isoprene emission it is crucial to establish how isoprene emissions are effected by plant acclimation to rising atmospheric CO2 levels. A promising development for modelling CO2-induced changes in isoprene emissions is the Leaf-Energetic-Status model (referred to as LES-model hereafter, see Harrison et al., 2013 and Morfopoulos et al., 2014). This model simulates isoprene emissions based on the hypothesis that isoprene biosynthesis depends on the imbalance between the photosynthetic electron supply of reducing power and the electron demands of carbon fixation. The energetic imbalance is critically related to the photosynthetic electron transport capacity (Jmax) and the maximum carboxylation capacity of Rubisco (Vcmax). Here we compare predictions of the LES-model with observed isoprene emission responses of Quercus robur (pedunculate oak) specimen that acclimated to CO2 growth conditions representative of the last glacial, the present and the end of this century (200, 400 and 800 ppm, respectively) for two growing seasons. These plants were grown in walk-in growth chambers with tight control of light, temperature, humidity and CO2 concentrations. Photosynthetic biochemical parameters Vcmax and Jmax were determined with a Licor LI-6400XT photosynthesis system. The relationship between photosynthesis and isoprene emissions was measured by coupling the photosynthesis system with a Proton-Transfer Reaction Time-of-Flight Mass Spectrometer. Our empirical results support the LES-model and show that the fractional allocation of carbon to isoprene biosynthesis is reduced in response to both short-term and long-term CO2 increases. In the short term, an increase in CO2 stimulates photosynthesis through an increase in the leaf interior CO2

  9. Effects of freezing and cold acclimation on the plasma membrane of isolated protoplasts

    Energy Technology Data Exchange (ETDEWEB)

    Steponkus, P.L.

    1991-01-01

    This project focuses on lesions in the plasma membrane of protoplasts that occur during freezing to temperatures below {minus}5{degrees} which result in changes in the semipermeablity of the plasma membrane. This injury, referred to as loss of osmotic responsiveness, is associated with the formation of large, aparticulate domains in the plasma membrane, aparticulate lamellae subtending the plasma membrane, and lamellar-to-hexagonal{sub II} phase transitions in the plasma membrane and subtending lamellar. The goals of this project are to provide a mechanistic understanding of the mechanism by which freeze-induced dehydration effects the formation of aparticulate domains and lamellar-to-hexagonal{sub II} phase transitions and to determine the mechanisms by which cold acclimation and cryoprotectants preclude or diminish these ultrastructural changes. Our working hypothesis is the formation of aparticulate domains and lamellar-to-hexagon{sub II} phase transitions in the plasma membrane and subtending lamellae are manifestations of hydration-dependent bilayer-bilayer interactions.

  10. Whole plant acclimation responses by finger millet to low nitrogen stress

    Directory of Open Access Journals (Sweden)

    Travis Luc Goron

    2015-08-01

    Full Text Available The small grain cereal, finger millet (FM, Eleusine coracana L. Gaertn, is valued by subsistence farmers in India and East Africa as a low-input crop. It is reported by farmers to require no added nitrogen, or only residual N, to produce grain. Exact mechanisms underlying the acclimation responses of FM to low N are largely unknown, both above and below ground. In particular, the responses of FM roots and root hairs to N or any other nutrient have not previously been reported. Given its low N requirement, FM also provides a rare opportunity to study long-term responses to N starvation in a cereal. The objective of this study was to survey the shoot and root morphometric responses of FM, including root hairs, to low N stress. Plants were grown in pails in a semi-hydroponic system on clay containing extremely low background N, supplemented with N or no N. To our surprise, plants grown without deliberately added N grew to maturity, looked relatively normal and produced healthy seed heads. Plants responded to the low N treatment by decreasing shoot, root and seed head biomass. These declines under low N were associated with decreased shoot tiller number, crown root number, total crown root length and total lateral root length, but with no consistent changes in root hair traits. Changes in tiller and crown root number appeared to coordinate the above and below ground acclimation responses to N. We discuss the remarkable ability of FM to grow to maturity without deliberately added N. The results suggest that FM should be further explored to understand this trait. Our observations are consistent with indigenous knowledge from subsistence farmers in Africa and Asia that this crop can survive extreme environments.

  11. Phycoerythrin-specific bilin lyase-isomerase controls blue-green chromatic acclimation in marine Synechococcus.

    Science.gov (United States)

    Shukla, Animesh; Biswas, Avijit; Blot, Nicolas; Partensky, Frédéric; Karty, Jonathan A; Hammad, Loubna A; Garczarek, Laurence; Gutu, Andrian; Schluchter, Wendy M; Kehoe, David M

    2012-12-04

    The marine cyanobacterium Synechococcus is the second most abundant phytoplanktonic organism in the world's oceans. The ubiquity of this genus is in large part due to its use of a diverse set of photosynthetic light-harvesting pigments called phycobiliproteins, which allow it to efficiently exploit a wide range of light colors. Here we uncover a pivotal molecular mechanism underpinning a widespread response among marine Synechococcus cells known as "type IV chromatic acclimation" (CA4). During this process, the pigmentation of the two main phycobiliproteins of this organism, phycoerythrins I and II, is reversibly modified to match changes in the ambient light color so as to maximize photon capture for photosynthesis. CA4 involves the replacement of three molecules of the green light-absorbing chromophore phycoerythrobilin with an equivalent number of the blue light-absorbing chromophore phycourobilin when cells are shifted from green to blue light, and the reverse after a shift from blue to green light. We have identified and characterized MpeZ, an enzyme critical for CA4 in marine Synechococcus. MpeZ attaches phycoerythrobilin to cysteine-83 of the α-subunit of phycoerythrin II and isomerizes it to phycourobilin. mpeZ RNA is six times more abundant in blue light, suggesting that its proper regulation is critical for CA4. Furthermore, mpeZ mutants fail to normally acclimate in blue light. These findings provide insights into the molecular mechanisms controlling an ecologically important photosynthetic process and identify a unique class of phycoerythrin lyase/isomerases, which will further expand the already widespread use of phycoerythrin in biotechnology and cell biology applications.

  12. Local cold acclimation during exercise and its effect on neuromuscular function of the hand.

    Science.gov (United States)

    Geurts, Carla L M; Sleivert, Gordon G; Cheung, Stephen S

    2006-12-01

    Most acclimation research is performed on resting individuals, whereas in real life, cold exposure is often accompanied by physical activity. We examined the effects of 2 weeks of repeated cold exposure of the hand with or without an elevated core temperature from exercise on neuromuscular function of the first dorsal interosseus (FDI) muscle and manual performance of the hand. The experimental group (4 female, 6 male; age, 25.1 +/- 6.9 y) cooled their hands in 8 degrees C water for 30 min daily while cycling (50% of heart rate reserve); the control group (4 female, 4 male; age, 25.1 +/- 5.7 y) remained still. Manual function testing consisted of tactile sensitivity, grip strength, manual dexterity, and evoked twitch force in a custom-made myograph. Thermal sensation, skin temperature of index finger (Tif) and hand (Tfdi), as well as rectal temperature (Tre), were recorded daily. Tre increased significantly during bicycling, by 0.6 +/- 0.2 degrees C. Minimal Tif and Tfdi of the groups combined increased significantly during exposure days from 8.7 +/- 0.7 degrees C and 12.4 +/- 2.8 degrees C to 10.1 +/- 1.3 degrees C and 15.0 +/- 3.0 degrees C, respectively (p=0.04), with no significant difference between groups. Thermal ratings improved significantly on exposure days. Manual function was impaired with cooling, but with no significant difference between groups or across time. Deterioration of twitch characteristics with cooling did not change with repeated cold exposure. Although the increasing core temperature during cold water immersion changed the acute temperature response and thermal ratings, it had no effect on local cold acclimation or manual function.

  13. Photosynthetic recovery and acclimation to excess light intensity in the rehydrated lichen soil crusts

    Science.gov (United States)

    Wu, Li; Lei, Yaping; Lan, Shubin; Hu, Chunxiang

    2017-01-01

    As an important successional stage and main type of biological soil crusts (BSCs) in Shapotou region of China (southeastern edge of Tengger Desert), lichen soil crusts (LSCs) often suffer from many stresses, such as desiccation and excess light intensity. In this study, the chlorophyll fluorescence and CO2 exchange in the rehydrated LSCs were detected under a series of photosynthetically active radiation (PAR) gradients to study the photosynthetic acclimation of LSCs. The results showed that although desiccation leaded to the loss of photosynthetic activity in LSCs, the fluorescence parameters including Fo, Fv and Fv/Fm of LSCs could be well recovered after rehydration. After the recovery of photosynthetic activity, the effective photosynthetic efficiency ΦPSII detected by Imaging PAM had declined to nearly 0 within both the lichen thallus upper and lower layers when the PAR increased to 200 μE m-2 s-1, however the net photosynthesis detected by the CO2 gas analyzer in the LSCs still appeared when the PAR increased to 1000 μE m-2 s-1. Our results indicate that LSCs acclimating to high PAR, on the one hand is ascribed to the special structure in crust lichens, making the incident light into the lichen thallus be weakened; on the other hand the massive accumulation of photosynthetic pigments in LSCs also provides a protective barrier for the photosynthetic organisms against radiation damage. Furthermore, the excessive light energy absorbed by crust lichens is also possibly dissipated by the increasing non-photochemical quenching, therefore to some extent providing some protection for LSCs. PMID:28257469

  14. Acclimation of photosynthetic parameters is not the icing on the cake. It is the cake.

    Science.gov (United States)

    Prentice, Iain Colin; Wang, Han; Togashi, Henrique; Keenan, Trevor; Davis, Tyler; Wright, Ian

    2015-04-01

    Photosynthesis and transpiration are tightly coupled through stomatal behaviour and therefore it is impossible to understand and parsimoniously model one without also considering the other. The ratio of leaf-internal to ambient carbon dioxide concentration (ci:ca ratio) is a measure of the "exchange rate" between water and carbon. We have shown that it is possible to predict the observed dependencies of ci:ca on environmental factors (temperature, vapour pressure deficit and atmospheric pressure) based on the "least-cost hypothesis", which states that plants minimize the sum of the unit costs (respiration per unit assimilation) of maintaining the capacities for carbon fixation (Vcmax) and water transport. Moreover, with the help of the "co-ordination hypothesis" (the long-accepted idea that Rubisco capacity and electron transport tend to co-limit photosynthesis) it is possible to predict not only how ci:ca should vary, but also how Vcmax and electron transport capacity (Jmax) should vary, in space and time. We will present empirical support for this idea based on both ecophysiological measurements at the leaf scale, and analysis of carbon dioxide flux measurements at the ecosystem scale. We conclude that acclimation of photosynthetic parameters is pervasive. This is fundamental because it predicts a quite different set of environmental responses than those that are usually applied in models that incorrectly assume constancy of parameter values with time and within plant functional types (PFTs). In addition, acclimation actually simplifies modelling because it describes universal relationships that apply across all PFTs with the C3 photosynthetic pathway, and it removes the need to specify parameters such as Vcmax and Jmax as if they were properties of PFTs.

  15. Morpholino gene knockdown in adult Fundulus heteroclitus: role of SGK1 in seawater acclimation.

    Directory of Open Access Journals (Sweden)

    Emily G Notch

    Full Text Available The Atlantic killifish (Fundulus heteroclitus is an environmental sentinel organism used extensively for studies on environmental toxicants and salt (NaCl homeostasis. Previous research in our laboratory has shown that rapid acclimation of killifish to seawater is mediated by trafficking of CFTR chloride channels from intracellular vesicles to the plasma membrane in the opercular membrane within the first hour in seawater, which enhances chloride secretion into seawater, thereby contributing to salt homeostasis. Acute transition to seawater is also marked by an increase in both mRNA and protein levels of serum glucocorticoid kinase 1 (SGK1 within 15 minutes of transfer. Although the rise in SGK1 in gill and its functional analog, the opercular membrane, after seawater transfer precedes the increase in membrane CFTR, a direct role of SGK1 in elevating membrane CFTR has not been established in vivo. To test the hypothesis that SGK1 mediates the increase in plasma membrane CFTR we designed two functionally different vivo-morpholinos to knock down SGK1 in gill, and developed and validated a vivo-morpholino knock down technique for adult killifish. Injection (intraperitoneal, IP of the splice blocking SGK1 vivo-morpholino reduced SGK1 mRNA in the gill after transition from fresh to seawater by 66%. The IP injection of the translational blocking and splice blocking vivo-morpholinos reduced gill SGK1 protein abundance in fish transferred from fresh to seawater by 64% and 53%, respectively. Moreover, knock down of SGK1 completely eliminated the seawater induced rise in plasma membrane CFTR, demonstrating that the increase in SGK1 protein is required for the trafficking of CFTR from intracellular vesicles in mitochondrion rich cells to the plasma membrane in the gill during acclimation to seawater. This is the first report of the use of vivo-morpholinos in adult killifish and demonstrates that vivo-morpholinos are a valuable genetic tool for this

  16. Effect of short-term heat acclimation with permissive dehydration on thermoregulation and temperate exercise performance.

    Science.gov (United States)

    Neal, R A; Corbett, J; Massey, H C; Tipton, M J

    2016-08-01

    We examined the effect of short-term heat acclimation with permissive dehydration (STHADe) on heat acclimation (HA) and cycling performance in a temperate environment. Ten trained male cyclists [mean (SD) maximal oxygen uptake: 63.3(4.0) mL/kg/min; peak power output (PPO): 385(40) W; training: 10 (3) h/week] underwent a STHADe program consisting of 5 days of exercise (maximum 90 min/day) in a hot environment (40 °C, 50% RH) to elicit isothermic heat strain [rectal temperature 38.64(0.27) °C]. Participants abstained from fluids during, and 30 min after, HA sessions. Pre- and post-STHADe HA was evaluated during euhydrated fixed-intensity exercise (60 min) in hot conditions; the effect of STHADe on thermoregulation was also examined under temperate conditions (20 min fixed-intensity exercise; 22 °C, 60% RH). Temperate cycling performance was assessed by a graded exercise test (GXT) and 20-km time trial (TT). STHADe reduced thermal and cardiovascular strain in hot and temperate environments. Lactate threshold [Δ = 16 (17) W] and GXT PPO [Δ = 6 (7) W] were improved following STHADe (P  0.05), although there was a trend for a higher mean power (P = 0.06). In conclusion, STHADE can reduce thermal and cardiovascular strain under hot and temperate conditions and there is some evidence of ergogenic potential for temperate exercise, but longer HA regimens may be necessary for this to meaningfully influence performance.

  17. Balancing photosynthetic electron flow is critical for cyanobacterial acclimation to nitrogen limitation.

    Science.gov (United States)

    Salomon, Eitan; Bar-Eyal, Leeat; Sharon, Shir; Keren, Nir

    2013-03-01

    Nitrogen limitation forces photosynthetic organisms to reallocate available nitrogen to essential functions. At the same time, it increases the probability of photo-damage by limiting the rate of energy-demanding metabolic processes, downstream of the photosynthetic apparatus. Non-diazotrophic cyanobacteria cope with this situation by decreasing the size of their phycobilisome antenna and by modifying their photosynthetic apparatus. These changes can serve two purposes: to provide extra amino-acids and to decrease excitation pressure. We examined the effects of nitrogen limitation on the form and function of the photosynthetic apparatus. Our aim was to study which of the two demands serve as the driving force for the remodeling of the photosynthetic apparatus, under different growth conditions. We found that a drastic reduction in light intensity allowed cells to maintain a more functional photosynthetic apparatus: the phycobilisome antenna was bigger, the activity of both photosystems was higher and the levels of photosystem (PS) proteins were higher. Pre-acclimating cells to Mn limitation, under which the activity of both PSI and PSII is diminished, results in a very similar response. The rate of PSII photoinhibition, in nitrogen limited cells, was found to be directly related to the activity of the photosynthetic apparatus. These data indicate that, under our experimental conditions, photo-damage avoidance was the more prominent determinant during the acclimation process. The combinations of limiting factors tested here is by no means artificial. Similar scenarios can take place under environmental conditions and should be taken into account when estimating nutrient limitations in nature.

  18. Emerging Perspectives on the Mechanisms,Regulation, and Distribution of Light Color Acclimation in Cyanobacteria

    Institute of Scientific and Technical Information of China (English)

    Andrian Gutu; David M. Kehoe

    2012-01-01

    Chromatic acclimation (CA) provides many cyanobacteria with the ability to tailor the properties of their lightharvesting antennae to the spectral distribution of ambient light.CA was originally discovered as a result of its dramatic cellular phenotype in red and green light.However,discoveries over the past decade have revealed that many pairs of light colors,ranging from blue to infrared,can trigger CA responses.The capacity to undergo CA is widespread geographically,occurs in most habitats around the world,and is found within all major cyanobacterial groups.In addition,many other cellular activities have been found to be under CA control,resulting in distinct physiological and morphological states for cells under different light-color conditions.Several types of CA appear to be the result of convergent evolution,where different strategies are used to achieve the final goal of optimizing light-harvesting antenna composition to maximize photon capture.The regulation of CA has been found to occur primarily at the level of RNA abundance.The CA-regulatory pathways uncovered thus far are two-component systems that use phytochrome-class photoreceptors with sensor-kinase domains to control response regulators that function as transcription factors.However,there is also at least one CAregulatory pathway that operates at the post-transcriptional level.It is becoming increasingly clear that large numbers of cyanobacterial species have the capacity to acclimate to a wide variety of light colors through the use of a range of different CA processes.

  19. Metabolomic analysis of cold acclimation of Arctic Mesorhizobium sp. strain N33.

    Directory of Open Access Journals (Sweden)

    Abdollah Ghobakhlou

    Full Text Available Arctic Mesorhizobium sp. N33 isolated from nodules of Oxytropis arctobia in Canada's eastern Arctic has a growth temperature range from 0 °C to 30 °C and is a well-known cold-adapted rhizobia. The key molecular mechanisms underlying cold adaptation in Arctic rhizobia remains totally unknown. Since the concentration and contents of metabolites are closely related to stress adaptation, we applied GC-MS and NMR to identify and quantify fatty acids and water soluble compounds possibly related to low temperature acclimation in strain N33. Bacterial cells were grown at three different growing temperatures (4 °C, 10 °C and 21 °C. Cells from 21 °C were also cold-exposed to 4°C for different times (2, 4, 8, 60 and 240 minutes. We identified that poly-unsaturated linoleic acids 18:2 (9, 12 & 18:2 (6, 9 were more abundant in cells growing at 4 or 10 °C, than in cells cultivated at 21 °C. The mono-unsaturated phospho/neutral fatty acids myristoleic acid 14:1(11 were the most significantly overexpressed (45-fold after 1 hour of exposure to 4 °C. As reported in the literature, these fatty acids play important roles in cold adaptability by supplying cell membrane fluidity, and by providing energy to cells. Analysis of water-soluble compounds revealed that isobutyrate, sarcosine, threonine and valine were more accumulated during exposure to 4 °C. These metabolites might play a role in conferring cold acclimation to strain N33 at 4 °C, probably by acting as cryoprotectants. Isobutyrate was highly upregulated (19.4-fold during growth at 4 °C, thus suggesting that this compound is a precursor for the cold-regulated fatty acids modification to low temperature adaptation.

  20. Antioxidant metabolism during acclimation of Begonia x erythrophylla to high light levels.

    Science.gov (United States)

    Burritt, David J; Mackenzie, Susan

    2003-06-01

    This study examined the influence of high light levels on antioxidant metabolism and the photosynthetic properties of Begonia x erythrophylla leaves. The pigment composition of shaded leaves and those developing in full sunlight was typical of shade- and sun-leaves, respectively. After 28 d in full sunlight, the preformed leaves of shade plants transferred to full sunlight (transferred-leaves) showed photo-bleaching with lower Chl (a + b) content and Chl a : Chl b ratios than shade-leaves, with Chl (a + b) : carotenoid ratios not significantly different. The variable/maximal fluorescence (Fv/Fm) of sun-leaves was not significantly different from that of shade-leaves, but transferred-leaves had reduced Fv : Fm ratios. Light response curves for the electron transport rate (ETR), the oxidation state of photosystem II (qP) and non-photochemical quenching (NPQ) showed significant differences between the three leaf types, with transferred-leaves not able to acclimate completely to full sunlight, having lower ETR, qP and NPQ values at high light levels than sun-leaves. Transfer to full sunlight caused a rapid increase in H2O2 and lipid hyperoxides, and a slight increase in protein oxidation. Ascorbate and glutathione levels decreased rapidly, as did the size of the total glutathione pool and, in addition to the general oxidation of proteins, rapid decreases in both the initial and total activities of chloroplastic fructose-1,6-bisphosphatase and glyceraldehyde-3-phosphate dehydrogenase were observed. These results suggest that a more oxidizing cellular environment is the likely cause of the photo-bleaching observed upon transfer of shade-leaves to full sunlight. Acclimation of transferred-leaves to full sunlight involved gradual increases in the activities of enzymes involved in antioxidant metabolism, including superoxide dismutase, catalase, glutathione reductase, ascorbate peroxidase, dehydroascorbate reductase and monodehydroascorbate reductase, but the levels of

  1. Self-regulating genomic island encoding tandem regulators confers chromatic acclimation to marine Synechococcus.

    Science.gov (United States)

    Sanfilippo, Joseph E; Nguyen, Adam A; Karty, Jonathan A; Shukla, Animesh; Schluchter, Wendy M; Garczarek, Laurence; Partensky, Frédéric; Kehoe, David M

    2016-05-24

    The evolutionary success of marine Synechococcus, the second-most abundant phototrophic group in the marine environment, is partly attributable to this group's ability to use the entire visible spectrum of light for photosynthesis. This group possesses a remarkable diversity of light-harvesting pigments, and most of the group's members are orange and pink because of their use of phycourobilin and phycoerythrobilin chromophores, which are attached to antennae proteins called phycoerythrins. Many strains can alter phycoerythrin chromophore ratios to optimize photon capture in changing blue-green environments using type IV chromatic acclimation (CA4). Although CA4 is common in most marine Synechococcus lineages, the regulation of this process remains unexplored. Here, we show that a widely distributed genomic island encoding tandem master regulators named FciA (for type four chromatic acclimation island) and FciB plays a central role in controlling CA4. FciA and FciB have diametric effects on CA4. Interruption of fciA causes a constitutive green light phenotype, and interruption of fciB causes a constitutive blue light phenotype. These proteins regulate all of the molecular responses occurring during CA4, and the proteins' activity is apparently regulated posttranscriptionally, although their cellular ratio appears to be critical for establishing the set point for the blue-green switch in ecologically relevant light environments. Surprisingly, FciA and FciB coregulate only three genes within the Synechococcus genome, all located within the same genomic island as fciA and fciB These findings, along with the widespread distribution of strains possessing this island, suggest that horizontal transfer of a small, self-regulating DNA region has conferred CA4 capability to marine Synechococcus throughout many oceanic areas.

  2. Methane production by fermentation cultures acclimated to waste from cattle fed monensin, lasalocid, salinomycin, or avoparcin

    Energy Technology Data Exchange (ETDEWEB)

    Varel, V.H.; Hashimoto, A.G.

    1982-12-01

    The ability of microorganisms to ferment waste from cattle fed monensin, lasalocid, or salinomycin to methane was determined. Continuously mixed anaerobic fermentors with 3-liter working volumes at 55 degrees C were used; fermentors were fed once per day. Initially, all fermentors were fed waste without antibiotics at 6% volatile solids (VSs, organic matter) and a 20-day retention time (RT) for 60 days. Waste from animals fed monensin, lasalocid, or salinomycin at 29, 20, and 16.5 mg per kg of feed, respectively, was added to duplicate fermentors at the above VSs, and RT. Avoparcin (5 to 45 mg/liter) was not fed to animals but was added directly to duplicate fermentors. Lasalocid and salinomycin had minimal effects of the rate of methane production at RTs of 20 days and later at 6.5 days. Avoparcin caused an increaes in organic acids from 599 to 1,672 mg/liter (as acetate) after 4 weeks, but by 6 weeks, acid concentrations declined and the rate of methane production was similar to controls at 6.5 day RT. The monensin fermentors stopped producing methane 3 weeks after antibiotic addition. However, after a 6-month acclimation period, the microorganisms apparently adapted, and methane production rates of 1.65 and 2.51 liters per liter of fermentor volume per day were obtained with 6% VSs, and RTs of 10 and 6.5 days, respectively. All fermentors that were fed waste containing antibiotics had lower pH values and ammonia and alkalinity concentrations, suggesting less buffering capacity and protein catabolism than in controls. Acclimation results obtained with fermentors at 35 degrees C were similar to those for fermentors at 55 degrees C. These studies indicate that waste from cattle fed these selected growth-promoting antibiotics can be thermophilically fermented to methane at RTs of 6.5 days or longer and VS concentrations of 6%, at rates comparable to waste without antibiotics. (Refs. 21).

  3. Exogenous Abscisic Acid Mimics Cold Acclimation for Cacti Differing in Freezing Tolerance.

    Science.gov (United States)

    Loik, M. E.; Nobel, P. S.

    1993-11-01

    The responses to low temperature were determined for two species of cacti sensitive to freezing, Ferocactus viridescens and Opuntia ficus-indica, and a cold hardy species, Opuntia fragilis. Fourteen days after shifting the plants from day/night air temperatures of 30/20[deg]C to 10/0[deg]C, the chlorenchyma water content decreased only for O. fragilis. This temperature shift caused the freezing tolerance (measured by vital stain uptake) of chlorenchyma cells to be enhanced only by about 2.0[deg]C for F. viridescens and O. ficus-indica but by 14.6[deg]C for O. fragilis. Also, maintenance of high water content by injection of water into plants at 10/0[deg]C reversed the acclimation. The endogenous abscisic acid (ABA) concentration was below 0.4 pmol g-1 fresh weight at 30/20[deg]C, but after 14 d at 10/0[deg]C it increased to 84 pmol g-1 fresh weight for O. ficus-indica and to 49 pmol g-1 fresh weight for O. fragilis. Four days after plants were sprayed with 7.5 x 10-5 M ABA at 30/20[deg]C, freezing tolerance was enhanced by 0.5[deg]C for F. viridescens, 4.1[deg]C for O. ficus-indica, and 23.4[deg]C for O. fragilis. Moreover, the time course for the change in freezing tolerance over 14 d was similar for plants shifted to low temperatures as for plants treated with exogenous ABA at moderate temperatures. Decreases in plant water content and increases in ABA concentration may be important for low-temperature acclimation by cacti, especially O. fragilis, which is widely distributed in Canada and the United States.

  4. Four-week cold acclimation in adult humans shifts uncoupling thermogenesis from skeletal muscles to brown adipose tissue.

    Science.gov (United States)

    Blondin, Denis P; Daoud, Amani; Taylor, Taryn; Tingelstad, Hans C; Bézaire, Véronic; Richard, Denis; Carpentier, André C; Taylor, Albert W; Harper, Mary-Ellen; Aguer, Céline; Haman, François

    2017-03-15

    Muscle-derived thermogenesis during acute cold exposure in humans consists of a combination of cold-induced increases in skeletal muscle proton leak and shivering. Daily cold exposure results in an increase in brown adipose tissue oxidative capacity coupled with a decrease in the cold-induced skeletal muscle proton leak and shivering intensity. Improved coupling between electromyography-determined muscle activity and whole-body heat production following cold acclimation suggests a maintenance of ATPase-dependent thermogenesis and decrease in skeletal muscle ATPase independent thermogenesis. Although daily cold exposure did not change the fibre composition of the vastus lateralis, the fibre composition was a strong predictor of the shivering pattern evoked during acute cold exposure. We previously showed that 4 weeks of daily cold exposure in humans can increase brown adipose tissue (BAT) volume by 45% and oxidative metabolism by 182%. Surprisingly, we did not find a reciprocal reduction in shivering intensity when exposed to a mild cold (18°C). The present study aimed to determine whether changes in skeletal muscle oxidative metabolism or shivering activity could account for these unexpected findings. Nine men participated in a 4 week cold acclimation intervention (10°C water circulating in liquid-conditioned suit, 2 h day(-1) , 5 days week(-1) ). Shivering intensity and pattern were measured continuously during controlled cold exposure (150 min at 4 °C) before and after the acclimation. Muscle biopsies from the m. vastus lateralis were obtained to measure oxygen consumption rate and proton leak of permeabilized muscle fibres. Cold acclimation elicited a modest 21% (P cold acclimation abolished the acute cold-induced increase in proton leak. Although daily cold exposure did not change the fibre composition of the m. vastus lateralis, fibre composition was a strong predictor of the shivering pattern evoked during acute cold. We conclude that muscle

  5. Acclimation to different thermal conditions in a northerly wintering shorebird is driven by body mass-related changes in organ size

    NARCIS (Netherlands)

    Vezina, Francois; Jalvingh, Kirsten M.; Dekinga, Anne; Piersma, Theunis

    2006-01-01

    Seasonal acclimatization and experimental acclimation to cold in birds typically results from increased shivering endurance and elevated thermogenic capacity leading to improved resistance to cold. A wide array of physiological adjustments, ranging from biochemical transformations to organ mass

  6. Cold acclimation of Arabidopsis thaliana results in incomplete recovery of photosynthetic capacity, associated with an increased reduction of the chloroplast stroma.

    Science.gov (United States)

    Savitch, L V; Barker-Astrom, J; Ivanov, A G; Hurry, V; Oquist, G; Huner, N P; Gardeström, P

    2001-12-01

    The effects of short-term cold stress and long-term cold acclimation on the light reactions of photosynthesis were examined in vivo to assess their contributions to photosynthetic acclimation to low temperature in Arabidopsis thaliana (L.) Heynh.. All photosynthetic measurements were made at the temperature of exposure: 23 degrees C for non-acclimated plants and 5 degrees C for cold-stressed and cold-acclimated plants. Three-day cold-stress treatments at 5 degrees C inhibited light-saturated rates of CO2 assimilation and O2 evolution by approximately 75%. The 3-day exposure to 5 degrees C also increased the proportion of reduced QA by 50%, decreased the yield of PSII electron transport by 65% and decreased PSI activity by 31%. In contrast, long-term cold acclimation resulted in a strong but incomplete recovery of light-saturated photosynthesis at 5 degrees C. The rates of light-saturated CO2 and O2 gas exchange and the in vivo yield of PSII activity under light-saturating conditions were only 35-40% lower, and the relative redox state of QA only 20% lower, at 5 degrees C after cold acclimation than in controls at 23 degrees C. PSI activity showed full recovery during long-term cold acclimation. Neither short-term cold stress nor long-term cold acclimation of Arabidopsis was associated with a limitation in ATP, and both treatments resulted in an increase in the ATP/NADPH ratio. This increase in ATP/NADPH was associated with an inhibition of PSI cyclic electron transport but there was no apparent change in the Mehler reaction activity in either cold-stressed or cold-acclimated leaves. Cold acclimation also resulted in an increase in the reduction state of the stroma, as indicated by an increased total activity and activation state of NADP-dependent malate dehydrogenase, and increased light-dependent activities of the major regulatory enzymes of the oxidative pentose-phosphate pathway. We suggest that the photosynthetic capacity during cold stress as well as cold

  7. CyAbrB2 Contributes to the Transcriptional Regulation of Low CO2 Acclimation in Synechocystis sp. PCC 6803.

    Science.gov (United States)

    Orf, Isabel; Schwarz, Doreen; Kaplan, Aaron; Kopka, Joachim; Hess, Wolfgang R; Hagemann, Martin; Klähn, Stephan

    2016-10-01

    Acclimation to low CO2 conditions in cyanobacteria involves the co-ordinated regulation of genes mainly encoding components of the carbon-concentrating mechanism (CCM). Making use of several independent microarray data sets, a core set of CO2-regulated genes was defined for the model strain Synechocystis sp. PCC 6803. On the transcriptional level, the CCM is mainly regulated by the well-characterized transcriptional regulators NdhR (= CcmR) and CmpR. However, the role of an additional regulatory protein, namely cyAbrB2 belonging to the widely distributed AbrB regulator family that was originally characterized in the genus Bacillus, is less defined. Here we present results of transcriptomic and metabolic profiling of the wild type and a ΔcyabrB2 mutant of Synechocystis sp. PCC 6803 after shifts from high CO2 (5% in air, HC) to low CO2 (0.04%, LC). Evaluation of the transcriptomic data revealed that cyAbrB2 is involved in the regulation of several CCM-related genes such as sbtA/B, ndhF3/ndhD3/cupA and cmpABCD under LC conditions, but apparently acts supplementary to NdhR and CmpR. Under HC conditions, cyAbrB2 deletion affects the transcript abundance of PSII subunits, light-harvesting components and Calvin-Benson-Bassham cycle enzymes. These changes are also reflected by down-regulation of primary metabolite pools. The data suggest a role for cyAbrB2 in adjusting primary carbon and nitrogen metabolism to photosynthetic activity under fluctuating environmental conditions. The findings were integrated into the current knowledge about the acquisition of inorganic carbon (Ci), the CCM and parts of its regulation on the transcriptional level. © The Author 2016. Published by Oxford University Press on behalf of Japanese Society of Plant Physiologists. All rights reserved. For permissions, please email: journals.permissions@oup.com.

  8. Effects of diapause and cold-acclimation on the avoidance of freezing injury in fat body tissue of the rice stem borer, Chilo suppressalis Walker.

    Science.gov (United States)

    Izumi, Yohei; Sonoda, Shoji; Tsumuki, Hisaaki

    2007-07-01

    Overwintering freeze-tolerant larvae of Chilo suppressalis can survive at -25 degrees C, but non-diapausing larvae cannot. We reported earlier that to prevent intracellular freezing, which causes death in overwintering larvae of the Saigoku ecotype distributed in southwestern Japan, water leaves and glycerol enters fat body cells through water channels during freezing. However, it is still unclear how diapause and low-temperature exposure are related to the acquisition of freeze tolerance. We compared the extent of tissue damage, accumulation of glycerol, and transport of glycerol and water in fat body tissues between cold-acclimated and non-acclimated non-diapausing and diapausing larvae. The tissue from cold-acclimated diapausing larvae could survive only when frozen in Grace's insect medium with 0.25 M glycerol at -20 degrees C. The protection provided by glycerol was offset by mercuric chloride, which is a water-channel inhibitor. Fat body tissue isolated from non-acclimated diapausing larvae was injured by freezing even though glycerol was added to the medium, but the level of freezing injury was significantly lower than in non-diapausing larvae. Radiotracer assays in cold-acclimated diapausing larvae showed that during freezing, water left the cells into the medium and glycerol entered the cells from the medium at the same time. Therefore, in Saigoku ecotype larvae of the rice stem borer, both diapause and cold-acclimation are essential to accumulate glycerol and activate aquaporin for the avoidance of freezing injury.

  9. Inter and intra-specific variation in photosynthetic acclimation response to long term exposure of elevated carbon dioxide

    Energy Technology Data Exchange (ETDEWEB)

    Wilkinson, M. [Univ. of Essex, Colchester (United Kingdom)]|[Writtle Coll. (United Kingdom)

    1996-08-01

    The response of intra and interspecific variation in photosynthetic acclimation to growth at elevated atmospheric CO{sub 2} concentration (600{micro}mol mol-l) in six important grassland species was investigated. Plants were grown in a background sward of Lolium perenne and measurements were made after four years of growth at elevated C{sub a}. Elevated CO{sub 2} was maintained using a FACE (Free-Air Carbon Enrichment) system. Significant intra and interspecific variation in acclimation response was demonstrated. The response of adaxial and abaxial stomatal conductance to elevated CO{sub 2} was also investigated. The stomatal conductance of both the adaxial and abaxial leaf surfaces was found to be reduced by elevated C{sub a}. Significant asymmetric responses in stomatal conductance was demonstrated in D. glomerata and T. pratense. Analysis of stomatal indices and densities indicated that the observed reductions in stomatal conductance were probably the result of changes in stomatal aperture.

  10. Temperature acclimation and heat tolerance of photosynthesis in Norwegian Saccharina latissima (Laminariales, Phaeophyceae)

    DEFF Research Database (Denmark)

    Sogn Andersen, Guri; Pedersen, Morten Foldager; Nielsen, Søren Laurentius

    2013-01-01

    performance, fluorescence parameters, and pigment concentrations were measured. S. latissima obtained almost identical photosynthetic characteristics when grown at 10 and 15°C, indicating thermal acclimation at these temperatures. In contrast, plants grown at 20°C suffered substantial tissue deterioration......, and showed reduced net photosynthetic capacity caused by a combination of elevated respiration and reduced gross photosynthesis due to lowered pigment concentrations, altered pigment composition, and reduced functionality of Photo-system II. Our results support the hypothesis that extraordinarily high....... We investigated the potential for thermal acclimation and heat tolerance in S. latissima collected from three locations along the south coast of Norway. Plants were kept in laboratory cultures at three different growth temperatures (10, 15, and 20°C) for 4–6 weeks, after which their photosynthetic...

  11. John Day Fall Chinook/Salmon Mitigation Plan Acclimation and Imprinting Site Feasibility Study: Summary Report : Completion Report.

    Energy Technology Data Exchange (ETDEWEB)

    U.S. Fish and Wildlife Service; Sverdrup Corporation; United States. Bonneville Power Administration.

    1987-09-01

    The purpose of this Plan is to replace upriver bright fall chinook salmon which were lost by construction of the John Day Dam. This will be accomplished by releasing salmon fry and smolts, incubated in the Spring Creek and Bonneville Hatcheries, at several upriver locations. Prior to release it is desired to feed and acclimate the juvenile fish to relieve the stress of truck transport, and to imprint them to the release site. This will ultimately produce adult chinook salmon that return to their historic spawning areas through traditional common property fisheries. It will also provide sexually mature broodstock fish that can be captured and spawned to supplement continued hatchery operation. This report summarizes results of an engineering feasibility study done for 10 potential acclimation sites on the Columbia, Yakima and Walla Walla Rivers. A detailed report has been prepared for each site and each is bound separately.

  12. Effect of short-term heat acclimation on endurance time and skin blood flow in trained athletes

    Directory of Open Access Journals (Sweden)

    Chen TI

    2013-06-01

    Full Text Available Tsung-I Chen,1,2 Pu-Hsi Tsai,3 Jui-Hsing Lin,4 Ning-Yuean Lee,5 Michael TC Liang61Graduate Institute of Sport Science, National Taiwan Sport University, Taoyuan, 2Center for Physical Education, Tzu Chi University, Hualien, 3Department of Sport and Leisure, National Quemoy University, Kinmen, 4Department of Physical Education, National Pingtung University of Education, Pingtung, 5College of Living Technology, Tainan University of Technology, Tainan, Taiwan; 6Department of Kinesiology and Health Promotion, California State Polytechnic University, Pomona, CA, USABackground: To examine whether short-term, ie, five daily sessions, vigorous dynamic cycling exercise and heat exposure could achieve heat acclimation in trained athletes and the effect of heat acclimation on cutaneous blood flow in the active and nonactive limb.Methods: Fourteen male badminton and table tennis athletes (age = 19.6 ± 1.2 years were randomized into a heat acclimation (EXP, n = 7 or nonheat acclimation (CON, n = 7 group. For 5 consecutive days, the EXP group was trained using an upright leg cycle ergometer in a hot environment (38.4°C ± 0.4°C, while the CON group trained in a thermoneutral environment (24.1°C ± 0.3°C. For both groups, the training intensity and duration increased from a work rate of 10% below ventilatory threshold (VT and 25 minutes per session on day 1, to 10% above VT and 45 minutes per session on day 5. Subjects performed two incremental leg cycle exercise tests to exhaustion at baseline and post-training in both hot and thermoneutral conditions. Study outcome measurements include: maximum oxygen uptake (VO2max; exercise heart rate (HR; O2 pulse; exercise time to exhaustion (tmax; skin blood flow in the upper arm (SkBFa and quadriceps (SkBFq; and mean skin (Tsk.Results: The significant heat-acclimated outcome measurements obtained during high-intensity leg cycling exercise in the high ambient environment are: (1 56%–100% reduction in cutaneous

  13. Cold-acclimation increases the predatory efficiency of the aphidophagous coccinellid Adalia bipunctata

    DEFF Research Database (Denmark)

    Sørensen, Christian Hougaard; Toft, Søren; Kristensen, Torsten Nygård

    2013-01-01

    Ladybirds are used in integrated pest management and augmentative biological control programs all over the world. Typically, commercial rearing of the commonly used ladybird, Adalia bipunctata, takes place at a constant temperature (25 °C) which maximizes reproductive output and survival in the l......Ladybirds are used in integrated pest management and augmentative biological control programs all over the world. Typically, commercial rearing of the commonly used ladybird, Adalia bipunctata, takes place at a constant temperature (25 °C) which maximizes reproductive output and survival...... in the laboratory. However, insects are known to acclimate via physiological adjustments to their thermal environment and performance is often higher at temperatures to which they are acclimated. Thus rearing A. bipunctata at 25 °C may not be optimal if they are to effectively manage aphid pests under different...

  14. Daily rhythms of core temperature and locomotor activity indicate different adaptive strategies to cold exposure in adult and aged mouse lemurs acclimated to a summer-like photoperiod.

    Science.gov (United States)

    Terrien, Jeremy; Zizzari, Philippe; Epelbaum, Jacques; Perret, Martine; Aujard, Fabienne

    2009-07-01

    Daily variations in core temperature (Tc) within the normothermic range imply thermoregulatory processes that are essential for optimal function and survival. Higher susceptibility towards cold exposure in older animals suggests that these processes are disturbed with age. In the mouse lemur, a long-day breeder, we tested whether aging affected circadian rhythmicity of Tc, locomotor activity (LA), and energy balance under long-day conditions when exposed to cold. Adult (N = 7) and aged (N = 5) mouse lemurs acclimated to LD14/10 were exposed to 10-day periods at 25 and 12 degrees C. Tc and LA rhythms were recorded by telemetry, and caloric intake (CI), body mass changes, and plasma IGF-1 were measured. During exposure to 25 degrees C, both adult and aged mouse lemurs exhibited strong daily variations in Tc. Aged animals exhibited lower levels of nocturnal LA and nocturnal and diurnal Tc levels in comparison to adults. Body mass and IGF-1 levels remained unchanged with aging. Under cold exposure, torpor bout occurrence was never observed whatever the age category. Adult and aged mouse lemurs maintained their Tc in the normothermic range and a positive energy balance. All animals exhibited increase in CI and decrease in IGF-1 in response to cold. The decrease in IGF-1 was delayed in aged mouse lemurs compared to adults. Moreover, both adult and aged animals responded to cold exposure by increasing their diurnal LA compared to those under Ta = 25 degrees C. However, aged animals exhibited a strong decrease in nocturnal LA and Tc, whereas cold effects were only slight in adults. The temporal organization and amplitude of the daily phase of low Tc were particularly well preserved under cold exposure in both age groups. Sexually active mouse lemurs exposed to cold thus seemed to prevent torpor exhibition and temporal disorganization of daily rhythms of Tc, even during aging. However, although energy balance was not impaired with age in mouse lemurs after cold exposure

  15. Expression dynamics of HSP90 and nitric oxide synthase (NOS) isoforms during heat stress acclimation in Tharparkar cattle

    Science.gov (United States)

    Bharati, Jaya; Dangi, S. S.; Bag, S.; Maurya, V. P.; Singh, G.; Kumar, P.; Sarkar, M.

    2017-08-01

    Six male Tharparkar cattle of 2-3 years old were selected for the study. After 15-day acclimation at thermoneutral zone (TNZ) in psychrometric chamber, animals were exposed at 42 °C for 6 h up to 23 days followed by 12 days of recovery period. Blood samples were collected during control period at TNZ (days 1, 5, and 12), after heat stress exposure (day 1, immediate heat stress acclimation (IHSA); days 2 to 10, short-term heat stress acclimation (STHSA); days 15 to 23, long-term heat stress acclimation (LTHSA); days 7 and 12, recovery period), and peripheral blood mononuclear cells (PBMCs) were isolated for RNA and protein extraction. The messenger RNA (mRNA) and protein expression in PBMCs were determined by qPCR and western blot, respectively. Samples at TNZ were taken as control. The mRNA expression of HSP90, iNOS, and eNOS was significantly upregulated ( P < 0.05) on day 1 (ISHA) as compared to control, remained consistent during STHSA, again increased during LTHSA, and finally reduced to basal level during recovery period. The protein expression of HSP90, iNOS, and eNOS were akin to their transcript pattern. PBMC culture study was conducted to study transcriptional abundance of HSP90, iNOS, and eNOS at different temperature-time combinations. The present findings indicate that HSP90, iNOS, and eNOS could possibly play an important role in mitigating thermal insults and confer thermotolerance during long-term heat stress exposure in Tharparkar cattle.

  16. Effects of heat acclimation on photosynthesis, antioxidant enzyme activities, and gene expression in orchardgrass under heat stress.

    Science.gov (United States)

    Zhao, Xin Xin; Huang, Lin Kai; Zhang, Xin Quan; Li, Zhou; Peng, Yan

    2014-09-01

    The present study was designed to examine the effects of heat acclimation on enzymatic activity, transcription levels, the photosynthesis processes associated with thermostability in orchardgrass (Dactylis glomerata L.).The stomatal conductance (Gs), net photosynthetic rate (Pn), and transpiration rates (Tr) of both heat-acclimated (HA) and non-acclimated (NA) plants were drastically reduced during heat treatment [using a 5-day heat stress treatment (38/30 °C ‒ day/night) followed by a 3-day recovery under control conditions (25/20 °C ‒ day/night), in order to consolidate the second cycle was permitted]. Water use efficiency increased more steeply in the HA (4.9 times) versus the NA (1.8 times) plants, and the intercellular CO2 concentration decreased gently in NA (10.9%) and HA (25.3%) plants after 20 d of treatments compared to 0 days'. Furthermore, heat-acclimated plants were able to maintain significant activity levels of superoxide disumutase (SOD), catalase (CAT), guaiacol peroxidase (POD), and transcription levels of genes encoding these enzymes; in addition, HA plants displayed lower malondialdehyde content and lower electrolyte leakage than NA plants. These results suggest that maintenance of activity and transcription levels of antioxidant enzymes as well as photosynthesis are associated with variable thermostability in HA and NA plants. This likely occurs through cellular membrane stabilization and improvements in water use efficiency in the photosynthetic process during heat stress. The association between antioxidant enzyme activity and gene expression, both of which may vary with genetic variation in heat tolerance, is important to further understand the molecular mechanisms that contribute to heat tolerance.

  17. Peripheral Sweat Gland Function, but not Whole-Body Sweat Rate, Increases in Women Following Humid Heat Acclimation

    Science.gov (United States)

    2009-10-01

    Specifically. following heat acclimation (HA) both men and women demonstrate similar reductions in traditional indicators of physiological stress. such as...stress. Environ. Res. 37, 1-11. Lee, J., Bae. J .. Matsumoto, T., Yang. H., Min, Y .. 2009. Tropical malaysians and temperate Koreans exhibit...E.R.W.e. (Eds.). Perspectives in Exercise Sciences and Sports Medicine Volume 6, Exercise. Heat, and Thermoregulation .. Brown Publishers. pp.85-118

  18. Major differences observed in transcript profiles of blueberry during cold acclimation under field and cold room conditions.

    Science.gov (United States)

    Dhanaraj, Anik L; Alkharouf, Nadim W; Beard, Hunter S; Chouikha, Imed B; Matthews, Benjamin F; Wei, Hui; Arora, Rajeev; Rowland, Lisa J

    2007-02-01

    Our laboratory has been working toward increasing our understanding of the genetic control of cold hardiness in blueberry (Vaccinium section Cyanococcus) to ultimately use this information to develop more cold hardy cultivars for the industry. Here, we report using cDNA microarrays to monitor changes in gene expression at multiple times during cold acclimation under field and cold room conditions. Microarrays contained over 2,500 cDNA inserts, approximately half of which had been picked and single-pass sequenced from each of two cDNA libraries that were constructed from cold acclimated floral buds and non-acclimated floral buds of the fairly cold hardy cv. Bluecrop (Vaccinium corymbosum L.). Two biological samples were examined at each time point. Microarray data were analyzed statistically using t tests, ANOVA, clustering algorithms, and online analytical processing (OLAP). Interestingly, more transcripts were found to be upregulated under cold room conditions than under field conditions. Many of the genes induced only under cold room conditions could be divided into three major types: (1) genes associated with stress tolerance; (2) those that encode glycolytic and TCA cycle enzymes, and (3) those associated with protein synthesis machinery. A few of the genes induced only under field conditions appear to be related to light stress. Possible explanations for these differences are discussed in physiological context. Although many similarities exist in how plants respond during cold acclimation in the cold room and in the field environment, there are major differences suggesting caution should be taken in interpreting results based only on artificial, cold room conditions.

  19. Products of lipid peroxidation, but not membrane susceptibility to oxidative damage, are conserved in skeletal muscle following temperature acclimation

    OpenAIRE

    Grim, Jeffrey M.; Semones, Molly C.; Kuhn, Donald E.; Kriska, Tamas; Keszler, Agnes; Crockett, Elizabeth L

    2014-01-01

    Changes in oxidative capacities and phospholipid remodeling accompany temperature acclimation in ectothermic animals. Both responses may alter redox status and membrane susceptibility to lipid peroxidation (LPO). We tested the hypothesis that phospholipid remodeling is sufficient to offset temperature-driven rates of LPO and, thus, membrane susceptibility to LPO is conserved. We also predicted that the content of LPO products is maintained over a range of physiological temperatures. To assess...

  20. Increased photosynthetic acclimation in alfalfa associated with arbuscular mycorrhizal fungi (AMF) and cultivated in greenhouse under elevated CO2.

    Science.gov (United States)

    Goicoechea, Nieves; Baslam, Marouane; Erice, Gorka; Irigoyen, Juan José

    2014-11-15

    Medicago sativa L. (alfalfa) can exhibit photosynthetic down-regulation when grown in greenhouse conditions under elevated atmospheric CO2. This forage legume can establish a double symbiosis with nitrogen fixing bacteria and arbuscular mycorrhizal fungi (AMF), which may increase the carbon sink effect of roots. Our aim was to assess whether the association of alfalfa with AMF can avoid, diminish or delay the photosynthetic acclimation observed in previous studies performed with nodulated plants. The results, however, showed that mycorrhizal (M) alfalfa at the end of their vegetative period had lower carbon (C) discrimination than non-mycorrhizal (NM) controls, indicating photosynthetic acclimation under ECO2 in plants associated with AMF. Decreased C discrimination was due to the acclimation of conductance, since the amount of Rubisco and the expression of genes codifying both large and small subunits of Rubisco were similar or slightly higher in M than in NM plants. Moreover, M alfalfa accumulated a greater amount of soluble sugars in leaves than NM plants, thus favoring a down-regulation effect on photosynthetic rates. The enhanced contents of sugars in leaves coincided with a reduced percentage of arbuscules in roots, suggesting decreased sink of carbohydrates from shoots to roots in M plants. The shorter life cycle of alfalfa associated with AMF in comparison with the NM controls may also be related to the accelerated photosynthetic acclimation in M plants. Further research is needed to clarify to what extent this behavior could be extrapolated to alfalfa cultivated in the field and subjected to periodic cutting of shoots under climatic change scenarios.

  1. Natural Resources Containing Arbutin. Determination of Arbutin in the Leaves of Bergenia crassifolia (L.) Fritsch. acclimated in Romania

    OpenAIRE

    Pop, Carmen; VLASE, LAURIAN; Mircea TAMAS

    2009-01-01

    Bergenia crassifolia (L.) Fritsch. is cited in literature as being one of the richest in arbutin (15-20%), an important pharmaceutical substance with disinfecting properties (in genitourinary diseases) and also depigmentation properties (skin whitening agent). The aim of this study consisted in determination of arbutin content in leaves of Bergenia crassifolia acclimated in Romania. The optimum parameters for the extraction of arbutin and the dynamics of the accumulation of arbutin in Bergeni...

  2. Influence of low- and high-elevation plant genomes on the regulation of autumn cold acclimation in Abies sachalinensis.

    Science.gov (United States)

    Ishizuka, Wataru; Ono, Kiyomi; Hara, Toshihiko; Goto, Susumu

    2015-01-01

    Boreal coniferous species with wide geographic distributions show substantial variation in autumn cold acclimation among populations. To determine how this variation is inherited across generations, we conducted a progeny test and examined the development of cold hardening in open-pollinated second-generation (F2) progeny of Abies sachalinensis. The F1 parents had different genetic backgrounds resulting from reciprocal interpopulational crosses between low-elevation (L) and high-elevation (H) populations: L × L, L × H, H × L, and H × H. Paternity analysis of the F2 progeny using molecular genetic markers showed that 91.3% of the fathers were located in surrounding stands of the F1 planting site (i.e., not in the F1 test population). The remaining fathers were assigned to F1 parents of the L × L cross-type. This indicates that the high-elevation genome in the F1 parents was not inherited by the F2 population via pollen flow. The timing of autumn cold acclimation in the F2 progeny depended on the cross-type of the F1 mother. The progeny of H × H mothers showed less damage in freezing tests than the progeny of other cross-types. Statistical modeling supported a linear effect of genome origin. In the best model, variation in freezing damage was explained by the proportion of maternally inherited high-elevation genome. These results suggest that autumn cold acclimation was partly explained by the additive effect of the responsible maternal genome. Thus, the offspring that inherited a greater proportion of the high-elevation genome developed cold hardiness earlier. Genome-based variation in the regulation of autumn cold acclimation matched the local climatic conditions, which may be a key factor in elevation-dependent adaptation.

  3. Influence of low- and high-elevation plant genomes on the regulation of autumn cold acclimation in Abies sachalinensis

    Directory of Open Access Journals (Sweden)

    Wataru eIshizuka

    2015-10-01

    Full Text Available Boreal coniferous species with wide geographic distributions show substantial variation in autumn cold acclimation among populations. To determine how this variation is inherited across generations, we conducted a progeny test and examined the development of cold hardening in open-pollinated second-generation (F2 progeny of Abies sachalinensis. The F1 parents had different genetic backgrounds resulting from reciprocal interpopulational crosses between low-elevation (L and high-elevation (H populations: L × L, L × H, H × L, and H × H. Paternity analysis of the F2 progeny using molecular genetic markers showed that 91.3% of the fathers were located in surrounding stands of the F1 planting site (i.e., not in the F1 test population. The remaining fathers were assigned to F1 parents of the L × L cross-type. This indicates that the high-elevation genome in the F1 parents was not inherited by the F2 population via pollen flow. The timing of autumn cold acclimation in the F2 progeny depended on the cross-type of the F1 mother. The progeny of H × H mothers showed less damage in freezing tests than the progeny of other cross-types. Statistical modeling supported a linear effect of genome origin. In the best model, variation in freezing damage was explained by the proportion of maternally inherited high-elevation genome. These results suggest that autumn cold acclimation was partly explained by the additive effect of the responsible maternal genome. Thus, the offspring that inherited a greater proportion of the high-elevation genome developed cold hardiness earlier. Genome-based variation in the regulation of autumn cold acclimation matched the local climatic conditions, which may be a key factor in elevation-dependent adaptation.

  4. Antioxidant Metabolism during Acclimation of Begonia × erythrophylla to High Light Levels

    Science.gov (United States)

    BURRITT, DAVID J.; MACKENZIE, SUSAN

    2003-01-01

    This study examined the influence of high light levels on antioxidant metabolism and the photosynthetic properties of Begonia × erythrophylla leaves. The pigment composition of shaded leaves and those developing in full sunlight was typical of shade‐ and sun‐leaves, respectively. After 28 d in full sunlight, the preformed leaves of shade plants transferred to full sunlight (transferred‐leaves) showed photo‐bleaching with lower Chl (a + b) content and Chl a : Chl b ratios than shade‐leaves, with Chl (a + b) : carotenoid ratios not significantly different. The variable/maximal fluorescence (Fv/Fm) of sun‐leaves was not significantly different from that of shade‐leaves, but transferred‐leaves had reduced Fv : Fm ratios. Light response curves for the electron transport rate (ETR), the oxidation state of photosystem II (qP) and non‐photochemical quenching (NPQ) showed significant differences between the three leaf types, with transferred‐leaves not able to acclimate completely to full sunlight, having lower ETR, qP and NPQ values at high light levels than sun‐leaves. Transfer to full sunlight caused a rapid increase in H2O2 and lipid hyperoxides, and a slight increase in protein oxidation. Ascorbate and glutathione levels decreased rapidly, as did the size of the total glutathione pool and, in addition to the general oxidation of proteins, rapid decreases in both the initial and total activities of chloroplastic fructose‐1,6‐bisphosphatase and glyceraldehyde‐3‐phosphate dehydrogenase were observed. These results suggest that a more oxidizing cellular environment is the likely cause of the photo‐bleaching observed upon transfer of shade‐leaves to full sunlight. Acclimation of transferred‐leaves to full sunlight involved gradual increases in the activities of enzymes involved in antioxidant metabolism, including superoxide dismutase, catalase, glutathione reductase, ascorbate peroxidase, dehydroascorbate reductase and

  5. Short-Term Molecular Acclimation Processes of Legume Nodules to Increased External Oxygen Concentration

    Science.gov (United States)

    Avenhaus, Ulrike; Cabeza, Ricardo A.; Liese, Rebecca; Lingner, Annika; Dittert, Klaus; Salinas-Riester, Gabriela; Pommerenke, Claudia; Schulze, Joachim

    2016-01-01

    Nitrogenase is an oxygen labile enzyme. Microaerobic conditions within the infected zone of nodules are maintained primarily by an oxygen diffusion barrier (ODB) located in the nodule cortex. Flexibility of the ODB is important for the acclimation processes of nodules in response to changes in external oxygen concentration. The hypothesis of the present study was that there are additional molecular mechanisms involved. Nodule activity of Medicago truncatula plants were continuously monitored during a change from 21 to 25 or 30% oxygen around root nodules by measuring nodule H2 evolution. Within about 2 min of the increase in oxygen concentration, a steep decline in nitrogenase activity occurred. A quick recovery commenced about 8 min later. A qPCR-based analysis of the expression of genes for nitrogenase components showed a tendency toward upregulation during the recovery. The recovery resulted in a new constant activity after about 30 min, corresponding to approximately 90% of the pre-treatment level. An RNAseq-based comparative transcriptome profiling of nodules at that point in time revealed that genes for nodule-specific cysteine-rich (NCR) peptides, defensins, leghaemoglobin and chalcone and stilbene synthase were significantly upregulated when considered as a gene family. A gene for a nicotianamine synthase-like protein (Medtr1g084050) showed a strong increase in count number. The gene appears to be of importance for nodule functioning, as evidenced by its consistently high expression in nodules and a strong reaction to various environmental cues that influence nodule activity. A Tnt1-mutant that carries an insert in the coding sequence (cds) of that gene showed reduced nitrogen fixation and less efficient acclimation to an increased external oxygen concentration. It was concluded that sudden increases in oxygen concentration around nodules destroy nitrogenase, which is quickly counteracted by an increased neoformation of the enzyme. This reaction might be

  6. FUM2, a Cytosolic Fumarase, Is Essential for Acclimation to Low Temperature in Arabidopsis thaliana1[OPEN

    Science.gov (United States)

    Dyson, Beth C.; Miller, Matthew A.E.; Feil, Regina; Rattray, Nicholas; Bowsher, Caroline G.

    2016-01-01

    Although cold acclimation is a key process in plants from temperate climates, the mechanisms sensing low temperature remain obscure. Here, we show that the accumulation of the organic acid fumaric acid, mediated by the cytosolic fumarase FUM2, is essential for cold acclimation of metabolism in the cold-tolerant model species Arabidopsis (Arabidopsis thaliana). A nontargeted metabolomic approach, using gas chromatography-mass spectrometry, identifies fumarate as a key component of the cold response in this species. Plants of T-DNA insertion mutants, lacking FUM2, show marked differences in their response to cold, with contrasting responses both in terms of metabolite concentrations and gene expression. The fum2 plants accumulated higher concentrations of phosphorylated sugar intermediates and of starch and malate. Transcripts for proteins involved in photosynthesis were markedly down-regulated in fum2.2 but not in wild-type Columbia-0. Plants of fum2 show a complete loss of the ability to acclimate photosynthesis to low temperature. We conclude that fumarate accumulation plays an essential role in low temperature sensing in Arabidopsis, either indirectly modulating metabolic or redox signals or possibly being itself directly involved in cold sensing. PMID:27440755

  7. A novel role for a TonB-family protein and photoregulation of iron acclimation in Fremyella diplosiphon.

    Science.gov (United States)

    Pattanaik, Bagmi; Montgomery, Beronda L

    2010-07-01

    Photosynthetic organisms display adaptations to changes in light and nutrient availability. Iron, which is required for the function of photosynthetic photosystems and other important biochemical processes, is an essential mineral that consequently impacts not only overall photosynthetic efficiency, but also the physiology of organisms in general. Our recent study represents the first functional characterization of a cyanobacterial TonB protein. TonB proteins classically are membrane proteins that support the transport of iron and vitamin B12 into cells. TonB proteins thus generally serve a critical role in organismal iron acclimation. We recently identified FdTonB, a TonB-family protein, in the filamentous freshwater cyanobacterium Fremyella diplosiphon. FdTonB contains conserved TonB residues and domains, as well as novel protein domains. Our recent study, however, supports a novel function for this protein in the photoregulation of morphology, rather than iron acclimation, in F. diplosiphon. Our detailed investigations into the responses of SF33 wild-type and ΔtonB mutant strains did not support a role for FdTonB in organismal responses to iron limitation. However, close examination of our recent results did highlight a novel interaction between light and iron acclimation in F. diplosiphon.

  8. Modulatory effect of betaine on expression dynamics of HSPs during heat stress acclimation in goat (Capra hircus).

    Science.gov (United States)

    Dangi, Satyaveer Singh; Dangi, Saroj K; Chouhan, V S; Verma, M R; Kumar, Puneet; Singh, Gyanendra; Sarkar, Mihir

    2016-01-10

    Changing climatic scenario with expected global rise in surface temperature compelled more focus of research over decoding heat stress response mechanism of animals and mitigation of heat stress. Recently betaine, a trimethyl form of glycine has been found to ameliorate heat stress in some species of animals. To overcome deleterious effect of heat stress, an attempt was taken to investigate the effect of betaine supplementation on heat stress mitigation in goats. Eighteen female Barbari goats were taken and randomly divided into 3 groups (n=6) such as control, HS (Heat stressed), HS+B (Heat stressed administered with betaine). Except for the control group, other groups were exposed to repeated heat stress (42 °C) for 6 h for sixteen consecutive days. Blood samples were collected at the end of heat exposure on day 1 (Initial heat stress acclimation - IHSA), day 6 (Short term heat stress acclimation - STHSA) and day 16 (Long term heat stress acclimation - LTHSA). When the groups were compared between different heat stress acclimatory phases, expression of all HSPs (HSP60, HSP70, HSP90 and HSP105/110) showed a similar pattern with a first peak on IHSA, reaching a basal level on STHSA followed by second peak on LTHSA. The messenger RNA (mRNA) and protein expression of HSPs was observed to be higher (Pbetaine administration was shown to have a dwindling effect on expression of HSPs, suggesting a possible role of this chemical chaperone on heat stress amelioration.

  9. Lipid remodelling in the reef-building honeycomb worm, Sabellaria alveolata, reflects acclimation and local adaptation to temperature

    Science.gov (United States)

    Muir, Anna P.; Nunes, Flavia L. D.; Dubois, Stanislas F.; Pernet, Fabrice

    2016-01-01

    Acclimation and adaptation, which are key to species survival in a changing climate, can be observed in terms of membrane lipid composition. Remodelling membrane lipids, via homeoviscous adaptation (HVA), counteracts membrane dysfunction due to temperature in poikilotherms. In order to assess the potential for acclimation and adaptation in the honeycomb worm, Sabellaria alveolata, a reef-building polychaete that supports high biodiversity, we carried out common-garden experiments using individuals from along its latitudinal range. Individuals were exposed to a stepwise temperature increase from 15 °C to 25 °C and membrane lipid composition assessed. Our results suggest that S. alveolata was able to acclimate to higher temperatures, as observed by a decrease in unsaturation index and 20:5n-3. However, over the long-term at 25 °C, lipid composition patterns are not consistent with HVA expectations and suggest a stress response. Furthermore, unsaturation index of individuals from the two coldest sites were higher than those from the two warmest sites, with individuals from the thermally intermediate site being in-between, likely reflecting local adaptation to temperature. Therefore, lipid remodelling appears limited at the highest temperatures in S. alveolata, suggesting that individuals inhabiting warm environments may be close to their upper thermal tolerance limits and at risk in a changing climate. PMID:27762300

  10. Cryobehavior of the plasma membrane in protoplasts isolated from cold-acclimated Arabidopsis leaves is related to surface area regulation.

    Science.gov (United States)

    Yamazaki, Tomokazu; Kawamura, Yukio; Uemura, Matsuo

    2008-06-01

    Extracellular freezing in plants results in dehydration and mechanical stresses upon the plasma membrane. Plants that acquire enhanced freezing tolerance after cold acclimation can withstand these two physical stresses. To understand the tolerance to freeze-induced physical stresses, the cryobehavior of the plasma membrane was observed using protoplasts isolated from cold-acclimated Arabidopsis thaliana leaves with the combination of a lipophilic fluorescent dye FM 1-43 and cryomicroscopy. We found that many vesicular structures appeared in the cytoplasmic region near the plasma membrane just after extracellular freezing occurred. These structures, referred to as freeze-induced vesicular structures (FIVs), then developed horizontally near the plasma membrane during freezing. There was a strong correlation between the increase in individual FIV size and the decrease in the surface area of the protoplasts during freezing. Some FIVs fused with their neighbors as the temperature decreased. Occasionally, FIVs fused with the plasma membrane, which may be necessary to relax the stress upon the plasma membrane during freezing. Vesicular structures resembling FIVs were also induced when protoplasts were mechanically pressed between a coverslip and slide glass. Fewer FIVs formed when protoplasts were subjected to hyperosmotic solution, suggesting that FIV formation is associated with mechanical stress rather than dehydration. Collectively, these results suggest that cold-acclimated plant cells may balance membrane tension in the plasma membrane by regulating the surface area. This enables plant cells to withstand the direct mechanical stress imposed by extracellular freezing.

  11. Human monocyte heat shock protein 72 responses to acute hypoxic exercise after 3 days of exercise heat acclimation.

    Science.gov (United States)

    Lee, Ben J; Mackenzie, Richard W A; Cox, Valerie; James, Rob S; Thake, Charles D

    2015-01-01

    The aim of this study was to determine whether short-term heat acclimation (STHA) could confer increased cellular tolerance to acute hypoxic exercise in humans as determined via monocyte HSP72 (mHSP72) expression. Sixteen males were separated into two matched groups. The STHA group completed 3 days of exercise heat acclimation; 60 minutes cycling at 50% V̇O2peak in 40°C 20% relative humidity (RH). The control group (CON) completed 3 days of exercise training in 20°C, 40% RH. Each group completed a hypoxic stress test (HST) one week before and 48 hours following the final day of CON or STHA. Percentage changes in HSP72 concentrations were similar between STHA and CON following HST1 (P = 0.97). STHA induced an increase in basal HSP72 (P = 0.03) with no change observed in CON (P = 0.218). Basal mHSP72 remained elevated before HST2 for the STHA group (P 0.05). Percent change in mHSP72 was lower after HST2 in STHA compared to CON (P = 0.02). The mHSP72 response to hypoxic exercise was attenuated following 3 days of heat acclimation. This is indicative of improved tolerance and ability to cope with the hypoxic insult, potentially mediated in part by increased basal reserves of HSP72.

  12. Nature and time course of acclimation to aluminum in juvenile brook trout (Salvelinus fontinalis): II. Gill histology

    Science.gov (United States)

    Mueller, M.E.; Sanchez, D.A.; Bergman, H.L.; McDonald, D.G.; Rhem, R.G.; Wood, C.M.

    1991-01-01

    Gill samples from juvenile brook trout (Salvelinus fontinalis) acclimated to low-level aluminum at pH 5.2 showed severe damage by day 4, with necrosis and fusion of secondary lamellae and hyperplasia and hypertrophy of mucous cells. Over the following 20 d, there was a continual process of repair with proliferation and hypertrophy of mucous cells. Qualitative analysis of gill samples plus physiology and mortality data collected in a companion study indicated progressive development (by day 10 onward) of increasing acclimation to Al. Quantitative analysis of gill samples on day 13 showed that mucous cell volume density had tripled and mucous cell area had doubled in Al-exposed fish compared with control fish. A lamellar fusion index showed evidence of fusion in Al-exposed fish by day 4 with recovery to nearly control levels by day 13. Physiological disturbances appear to be directly related to the histological changes observed in the gill epithelium. At the cellular level, changes in either mucous cell production and secretion or changes in mucus chemistry contribute, in part, to acclimation to Al.

  13. Acclimation of biochemical and diffusive components of photosynthesis in rice, wheat and maize to heat and water deficit: implications for modeling photosynthesis

    Directory of Open Access Journals (Sweden)

    Juan Alejandro Perdomo

    2016-11-01

    Full Text Available The impact of the combined effects of heat stress, increased vapor pressure deficit (VPD and water deficit on the physiology of major crops needs to be better understood to help identifying the expected negative consequences of climate change and heat waves on global agricultural productivity. To address this issue, rice, wheat and maize plants were grown under control temperature (CT, 25°C, VPD 1.8 kPa, and a high temperature (HT, 38°C, VPD 3.5 kPa, both under well-watered (WW and water deficit (WD conditions. Gas-exchange measurements showed that, in general, WD conditions affected the leaf conductance to CO2, while growth at HT had a more marked effect on the biochemistry of photosynthesis. When combined, HT and WD had an additive effect in limiting photosynthesis. The negative impacts of the imposed treatments on the processes governing leaf gas-exchange were species-dependent. Wheat presented a higher sensitivity while rice and maize showed a higher acclimation potential to increased temperature. Rubisco and PEPC kinetic constants determined in vitro at 25°C and 38°C were used to estimate Vcmax, Jmax and Vpmax in the modeling of C3 and C4 photosynthesis. The results here obtained reiterate the need to use species-specific and temperature-specific values for Rubisco and PEPC kinetic constants for a precise parameterization of the photosynthetic response to changing environmental conditions in different crop species.

  14. Chromatic acclimation and population dynamics of green sulfur bacteria grown with spectrally tailored light.

    Science.gov (United States)

    Saikin, Semion K; Khin, Yadana; Huh, Joonsuk; Hannout, Moataz; Wang, Yaya; Zare, Farrokh; Aspuru-Guzik, Alán; Tang, Joseph Kuo-Hsiang

    2014-05-27

    Living organisms have to adjust to their surrounding in order to survive in stressful conditions. We study this mechanism in one of most primitive creatures - photosynthetic green sulfur bacteria. These bacteria absorb photons very efficiently using the chlorosome antenna complexes and perform photosynthesis in extreme low-light environments. How the chlorosomes in green sulfur bacteria are acclimated to the stressful light conditions, for instance, if the spectrum of light is not optimal for absorption, is unknown. Studying Chlorobaculum tepidum cultures with far-red to near-infrared light-emitting diodes, we found that these bacteria react to changes in energy flow by regulating the amount of light-absorbing pigments and the size of the chlorosomes. Surprisingly, our results indicate that the bacteria can survive in near-infrared lights capturing low-frequency photons by the intermediate units of the light-harvesting complex. The latter strategy may be used by the species recently found near hydrothermal vents in the Pacific Ocean.

  15. Diatom acclimation to elevated CO2 via cAMP signalling and coordinated gene expression

    Science.gov (United States)

    Hennon, Gwenn M. M.; Ashworth, Justin; Groussman, Ryan D.; Berthiaume, Chris; Morales, Rhonda L.; Baliga, Nitin S.; Orellana, Mónica V.; Armbrust, E. V.

    2015-08-01

    Diatoms are responsible for ~40% of marine primary productivity, fuelling the oceanic carbon cycle and contributing to natural carbon sequestration in the deep ocean. Diatoms rely on energetically expensive carbon concentrating mechanisms (CCMs) to fix carbon efficiently at modern levels of CO2 (refs , , ). How diatoms may respond over the short and long term to rising atmospheric CO2 remains an open question. Here we use nitrate-limited chemostats to show that the model diatom Thalassiosira pseudonana rapidly responds to increasing CO2 by differentially expressing gene clusters that regulate transcription and chromosome folding, and subsequently reduces transcription of photosynthesis and respiration gene clusters under steady-state elevated CO2. These results suggest that exposure to elevated CO2 first causes a shift in regulation, and then a metabolic rearrangement. Genes in one CO2-responsive cluster included CCM and photorespiration genes that share a putative cAMP-responsive cis-regulatory sequence, implying these genes are co-regulated in response to CO2, with cAMP as an intermediate messenger. We verified cAMP-induced downregulation of CCM gene δ-CA3 in nutrient-replete diatom cultures by inhibiting the hydrolysis of cAMP. These results indicate an important role for cAMP in downregulating CCM and photorespiration genes under elevated CO2 and provide insights into mechanisms of diatom acclimation in response to climate change.

  16. Are sun- and shade-type anatomy required for the acclimation of Neoregelia cruenta?

    Science.gov (United States)

    Reinert, Fernanda; Leal-Costa, Marcos V; Junqueira, Nícia E; Tavares, Eliana S

    2013-01-01

    Sun and shade plants are often discriminated by a number of sun- and shade-type anatomies. Nonetheless, we propose that among tank-bromeliads, changes in rosette architecture satisfy the requirements for coping with contrasting light levels. The tank-bromeliad Neoregelia cruenta naturally colonises sub-habitats ranging from full exposure to direct sunlight, to shaded environments in sand ridge plains. We quantified anatomical and morphological traits of leaves and rosettes of N. cruenta grown under sun and shade conditions. Cells with undulated lateral walls within the water parenchyma are for the first time described for the family. Under high light, leaf blades were wider, shorter, and yellowish. The rosette diameter of sun plants was less than half that of shade plants. Sun leaves overlapped with neighbouring leaves for most of their length, forming a cylindrical rosette where water accumulates. Shade leaves only overlapped in the centre of the rosette. Most anatomical traits were similar under both growth conditions. Stomata were absent from the base of sun leaves, which is probably explained by limited gas exchange at the base of the tight sun-type rosette. Data suggest that the ability of N. cruenta to acclimate to sun and shade is better explained by changes in rosette architecture than by leaf anatomy.

  17. Are sun- and shade-type anatomy required for the acclimation of Neoregelia cruenta?

    Directory of Open Access Journals (Sweden)

    FERNANDA REINERT

    2013-06-01

    Full Text Available Sun and shade plants are often discriminated by a number of sun- and shade-type anatomies. Nonetheless, we propose that among tank-bromeliads, changes in rosette architecture satisfy the requirements for coping with contrasting light levels. The tank-bromeliad Neoregelia cruenta naturally colonises sub-habitats ranging from full exposure to direct sunlight, to shaded environments in sand ridge plains. We quantified anatomical and morphological traits of leaves and rosettes of N. cruenta grown under sun and shade conditions. Cells with undulated lateral walls within the water parenchyma are for the first time described for the family. Under high light, leaf blades were wider, shorter, and yellowish. The rosette diameter of sun plants was less than half that of shade plants. Sun leaves overlapped with neighbouring leaves for most of their length, forming a cylindrical rosette where water accumulates. Shade leaves only overlapped in the centre of the rosette. Most anatomical traits were similar under both growth conditions. Stomata were absent from the base of sun leaves, which is probably explained by limited gas exchange at the base of the tight sun-type rosette. Data suggest that the ability of N. cruenta to acclimate to sun and shade is better explained by changes in rosette architecture than by leaf anatomy.

  18. Changes in membrane lipids and carotenoids during light acclimation in a marine cyanobacterium Synechococcus sp.

    Indian Academy of Sciences (India)

    Olimpio Montero; Alberto Sánchez-Guijo; Luis M Lubián; Gonzalo Martínez-Rodríguez

    2012-09-01

    Time course of carotenoid and membrane lipid variation during high light (HL) acclimation (about 85 mol m−2 s−1), after transfer from low light (LL) (5–10 μmol m−2 s−1), was determined in a marine Synechococcus strain. High-performance liquid chromatography (HPLC) coupled to diode array detector (DAD) or electrospray ionization mass spectrometry (ESI-MS) was used for compound separation and detection. Myxoxanthophyll rose within a time interval of 8 h to 24 h after the onset of exposure to HL. -carotene content started to decrease after 4 h of the onset of exposure to HL. Zeaxanthin content rose with exposure to HL, but it was only significant after 24 h of exposure. Carotenoid changes are in agreement with a coordinated activity of the enzymes of the myxoxanthophyll biosynthetic pathway, with no rate-limiting intermediate steps. Lipid analysis showed all species with a C18:3/C16:0 composition increased their content, the changes of PG(18:3/16:0) and MGDG(18:3/16:0) being primarily significant. Major lipid changes were also found to occur within 24 h. These changes might suggest reduction and reorganization of the thylakoid membrane structure. Hypotheses are also drawn on the role played by lipid molecule shape and their possible effect in membrane fluidity and protein accommodation.

  19. Study on Seawater-acclimation Spirulina%海水驯化螺旋藻研究

    Institute of Scientific and Technical Information of China (English)

    关邵晨; 王璇; 李杰; 秦琅; 董仁杰; 朱毅

    2012-01-01

    [Objective] The aim was to seek Spirulina culture methods with seawater. [Method] Spirulina was habituated culture progressively with prepared seawater-acclimation solution, moreover, the morphological changes of Spirulina were observed and its biochemical indicators were measured. [Result]The new algaes was obtained, it has better stability and average length was greater than Spirulina in fresh water, its chlorophyll content was substantially unchanged, and the concentration of phycocyanin increased by 62.8% compared with Spirulina in fresh water. [Conclusion] The method can save resources and cost, which lay the foundation for large scale production and processing of Spirulina.%[目的]探寻螺旋藻的海水培养方法.[方法]用配制的海水驯化培养液对螺旋藻进行逐级驯化培养,观察螺旋藻的形态学变化并测量其生化指标.[结果]得到了平均长度大于淡水螺旋藻且稳定性良好的藻种,其叶绿素含量基本不变,藻蓝蛋白浓度较淡水培养的螺旋藻增加了62.8%.[结论]该方法可节省资源和成本,为螺旋藻的规模化生产和加工奠定了基础.

  20. Global cooling: cold acclimation and the expression of soluble proteins in carp skeletal muscle.

    Science.gov (United States)

    McLean, Lynn; Young, Iain S; Doherty, Mary K; Robertson, Duncan H L; Cossins, Andrew R; Gracey, Andrew Y; Beynon, Robert J; Whitfield, Phillip D

    2007-08-01

    The common carp (Cyprinus carpio) has a well-developed capacity to modify muscle properties in response to changes in temperature. Understanding the mechanisms underpinning this phenotypic response at the protein level may provide fundamental insights into the molecular basis of adaptive processes in skeletal muscle. In this study, common carp were subjected to a cooling regimen and soluble extracts of muscle homogenates were separated by 1-D SDS-PAGE and 2-DE. Proteins were identified using MALDI-TOF-MS and de novo peptide sequencing using LC-MS/MS. The 2-D gel was populated with numerous protein spots that were fragments of all three muscle isoforms (M1, M2 and M3) of carp creatine kinase (CK). The accumulation of the CK fragments was enhanced when the carp were cooled to 10 degrees C. The protein changes observed in the skeletal muscle of carp subjected to cold acclimation were compared to changes described in a previous transcript analysis study. Genes encoding CK isoforms were downregulated and the genes encoding key proteins of the ubiquitin-proteasome pathway were upregulated. These findings are consistent with a specific cold-induced enhancement of proteolysis of CK.

  1. Acclimation of Pistacia integerrima trees to frost in semi-arid environments depends on autumn's drought.

    Science.gov (United States)

    Sperling, Or; Secchi, Francesca; Godfrey, Jessie; Zwieniecki, Maciej A

    2017-03-01

    Main conclusion Cold acclimation is revealed through induced stem respiration during pre-winter frost of native Pistacia integerrima trees in continental semi-arid environments. Semi-arid environments challenge vegetation by simultaneous abiotic stresses. In this study, we examine the combined effects of water stress and frost on the physiology of Pistacia integerrima stems. This species is native to semi-arid environments where drought and frost frequently co-occur. We quantified carbohydrates and proline in P. integerrima stems responding to frost and experiencing water potentials between -0.2 and -1.8 MPa. We report that dehydrated trees (i.e., Ψstem <=-1 MPa) had more soluble sugars and proline than the well-watered trees (-0.2 MPa). The dehydrated trees also froze at lower temperatures and were less damaged by freezing. Interestingly, we observed a significant increase in stem CO2 efflux at near-freezing temperatures that could be linked to frost protection. This novel finding challenges current paradigm of plant respiration-kinetics which predicts, according to Arrhenius equation, lower respiration rates during frost. Our results support the notion that drought and frost are analogous stresses that can independently activate corresponding physiological processes in trees and amplify protection. This inevitable stress response 'collaboration' may be the key to understanding how non-dormant perennial plants survive the highly variable weather patterns of early winters in semi-arid environments.

  2. Methane production from rice straw with acclimated anaerobic sludge: effect of phosphate supplementation.

    Science.gov (United States)

    Lei, Zhongfang; Chen, Jiayi; Zhang, Zhenya; Sugiura, Norio

    2010-06-01

    Rice straw particles were directly used as substrate for anaerobic digestion with acclimated sludge under room temperature and different levels of phosphate. Two obvious biogas production peaks were observed for all reactors, with biogas or methane yields of (0.33-0.35)m(3)/kg-VS loaded or (0.27-0.29)m(3) CH(4)/kg-VS loaded and average methane contents of 75.9-78.2%. A separated two-stage first-order kinetic model was developed in this study and showed a good fit to the experimental data when this complicated process was divided into two stages. The average biogas and methane production rate constants were (0.027-0.031)d(-1) and (0.028-0.033)d(-1), respectively, increased by 2-3 times in the second stages than those in the first. The results indicated that an adequate level of phosphate addition (465 mg-P/L) could accelerate the biogasification process: 7-13 days earlier appearance of the two peaks and shorter time needed for complete biogasification of rice straw.

  3. Construction of a Miniaturized Chromatic Acclimation Sensor from Cyanobacteria with Reversed Response to a Light Signal

    Science.gov (United States)

    Nakajima, Mitsuharu; Ferri, Stefano; Rögner, Matthias; Sode, Koji

    2016-11-01

    Cyanobacteria harbor unique photoreceptors, designated as cyanobacteriochromes (CBCRs). In this study, we attempted to engineer the chromatic acclimation sensor CcaS, a CBCR derived from the cyanobacterium Synechocystis sp. PCC 6803. The wild-type CcaS induces gene expression under green light illumination and represses it under red light illumination. We focused on the domain structure of CcaS, which consists of an N-terminal transmembrane helix; a GAF domain, which serves as the sensor domain; a linker region (L1); two PAS domains; a second linker region (L2); and a C-terminal histidine kinase (HK) domain. Truncated versions of the photoreceptor were constructed by removing the L1 linker region and the two PAS domains, and fusing the GAF and HK domains with a truncated linker region. Thus constructed “miniaturized CcaSs” were grouped into four distinct categories according to their responses toward green and red light illumination, with some showing improved gene regulation compared to the wild type. Remarkably, one of the miniaturized CcaSs induced gene expression under red light and repressed it under green light, a reversed response to the light signal compared to wild type CcaS. These characteristics of engineered photoreceptors were discussed by analyzing the CcaS structural model.

  4. A gene island with two possible configurations is involved in chromatic acclimation in marine Synechococcus.

    Science.gov (United States)

    Humily, Florian; Partensky, Frédéric; Six, Christophe; Farrant, Gregory K; Ratin, Morgane; Marie, Dominique; Garczarek, Laurence

    2013-01-01

    Synechococcus, the second most abundant oxygenic phototroph in the marine environment, harbors the largest pigment diversity known within a single genus of cyanobacteria, allowing it to exploit a wide range of light niches. Some strains are capable of Type IV chromatic acclimation (CA4), a process by which cells can match the phycobilin content of their phycobilisomes to the ambient light quality. Here, we performed extensive genomic comparisons to explore the diversity of this process within the marine Synechococcus radiation. A specific gene island was identified in all CA4-performing strains, containing two genes (fciA/b) coding for possible transcriptional regulators and one gene coding for a phycobilin lyase. However, two distinct configurations of this cluster were observed, depending on the lineage. CA4-A islands contain the mpeZ gene, encoding a recently characterized phycoerythrobilin lyase-isomerase, and a third, small, possible regulator called fciC. In CA4-B islands, the lyase gene encodes an uncharacterized relative of MpeZ, called MpeW. While mpeZ is expressed more in blue light than green light, this is the reverse for mpeW, although only small phenotypic differences were found among chromatic acclimaters possessing either CA4 island type. This study provides novel insights into understanding both diversity and evolution of the CA4 process.

  5. A gene island with two possible configurations is involved in chromatic acclimation in marine Synechococcus.

    Directory of Open Access Journals (Sweden)

    Florian Humily

    Full Text Available Synechococcus, the second most abundant oxygenic phototroph in the marine environment, harbors the largest pigment diversity known within a single genus of cyanobacteria, allowing it to exploit a wide range of light niches. Some strains are capable of Type IV chromatic acclimation (CA4, a process by which cells can match the phycobilin content of their phycobilisomes to the ambient light quality. Here, we performed extensive genomic comparisons to explore the diversity of this process within the marine Synechococcus radiation. A specific gene island was identified in all CA4-performing strains, containing two genes (fciA/b coding for possible transcriptional regulators and one gene coding for a phycobilin lyase. However, two distinct configurations of this cluster were observed, depending on the lineage. CA4-A islands contain the mpeZ gene, encoding a recently characterized phycoerythrobilin lyase-isomerase, and a third, small, possible regulator called fciC. In CA4-B islands, the lyase gene encodes an uncharacterized relative of MpeZ, called MpeW. While mpeZ is expressed more in blue light than green light, this is the reverse for mpeW, although only small phenotypic differences were found among chromatic acclimaters possessing either CA4 island type. This study provides novel insights into understanding both diversity and evolution of the CA4 process.

  6. EFFECTS OF 4-CHLOROPHENOL LOADINGS ON ACCLIMATION OF BIOMASS WITH OPTIMIZED FIXED TIME SEQUENCING BATCH REACTOR

    Directory of Open Access Journals (Sweden)

    H. Movahedyan, A. Assadi, M. M. Amin

    2008-10-01

    Full Text Available Abstract: Chlorinated phenols in many industrial effluents are usually difficult to be removed by conventional biological treatment processes. Performance of the aerobic sequencing batch reactor treating 4-chlorophenol containing wastewater at different loadings rates from 0.0075 to 1.2 g4CP/L.d was evaluated. The sequencing batch reactor was operated with fill, react, settle and decant phases in the order of 10:370:90:10 min, respectively, for a cycle time of 8 h at 10 days solid retention time and 16 h hydraulic retention time in the stable period. The effects of 4-chlorophenol loadings on the 4-chlorophenol and chemical oxygen demand removal percents, yield coefficient (Y, biomass variation and sludge volume index were investigated. High chemical oxygen demand removal efficiencies (95±3.5% and approximately complete 4-chlorophenol removal (>99% were observed even in the absence of growth substrate. The degradation of 4-chlorophenol led to formation of 5-chloro-2-hydroxymuconic semialdehyde, which was more oxidized, indicating complete disappearance of 4-chlorophenol via meta-cleavage pathway. A compact sludge with excellent settleability (sludge volume index=47±6.1 mL/g developed during entire acclimation period. High removal efficiencies with sequencing batch reactor may be due to enforced short term unsteady state conditions coupled with periodic exposure of the microorganisms to defined process conditions which facilitate the required metabolic pathways for treating xenobiotics containing wastewater.

  7. Meta-omic analyses of Baltic Sea cyanobacteria: diversity, community structure and salt acclimation.

    Science.gov (United States)

    Celepli, Narin; Sundh, John; Ekman, Martin; Dupont, Chris L; Yooseph, Shibu; Bergman, Birgitta; Ininbergs, Karolina

    2017-02-01

    Cyanobacteria are important phytoplankton in the Baltic Sea, an estuarine-like environment with pronounced north to south gradients in salinity and nutrient concentrations. Here, we present a metagenomic and -transcriptomic survey, with subsequent analyses targeting the genetic identity, phylogenetic diversity, and spatial distribution of Baltic Sea cyanobacteria. The cyanobacterial community constituted close to 12% of the microbial population sampled during a pre-bloom period (June-July 2009). The community was dominated by unicellular picocyanobacteria, specifically a few highly abundant taxa (Synechococcus and Cyanobium) with a long tail of low abundance representatives, and local peaks of bloom-forming heterocystous taxa. Cyanobacteria in the Baltic Sea differed genetically from those in adjacent limnic and marine waters as well as from cultivated and sequenced picocyanobacterial strains. Diversity peaked at brackish salinities 3.5-16 psu, with low N:P ratios. A shift in community composition from brackish to marine strains was accompanied by a change in the repertoire and expression of genes involved in salt acclimation. Overall, the pre-bloom cyanobacterial population was more genetically diverse, widespread and abundant than previously documented, with unicellular picocyanobacteria being the most abundant clade along the entire Baltic Sea salinity gradient. © 2017 The Authors. Environmental Microbiology published by Society for Applied Microbiology and John Wiley & Sons Ltd.

  8. Wind-acclimated thallus morphogenesis in a lichen (Evernia prunastri, Parmeliaceae) probably favored by grazing.

    Science.gov (United States)

    Prinzing, A J

    1999-02-01

    How does the morphogenesis of a widespread epiphytic lichen interact with the environment, leading to amazingly polymorphic and wind-tolerant fruticose thalli? A series of photographs showed that the normal branches were basically even and flat with isotomic-dichotomous branchings. Numerous deviations from this basic regular pattern were found and traced back to their origins in the asymmetry of the branches' cross sections. This was observed quantitatively (statistically testable) in the field, while the thalli were growing. This large variability in growth of single branches was a prerequisite for the polymorphism seen in complete thallus growth forms. The structure and distribution of the mentioned important asymmetries in branch cross sections can best be explained by the effect of grazing on cortex and phycobiont layer. Very small-scale growth observations and experimental simulation confirmed this. In thalli with many such small-scale variations in branch growth the overall thallus growth form became wind acclimated as a result of the selective effect of wind exposure on the thallus phenotype: branches growing windwardly grew more slowly. Such thalli were well protected from being dislodged by wind, and they desiccate slowly as demonstrated by a previous study.

  9. Reduction of RNA A-to-I editing in Drosophila acclimated to heat shock

    Directory of Open Access Journals (Sweden)

    Joel Stocker

    2013-09-01

    Full Text Available Although an increasing number of RNA adenosine-to-inosine (A-to-I editing sites are being discovered, how the editing frequencies of these sites are modulated to fine-tune protein function in adaptive responses is not well understood. A previous study screening for heat tolerance in Drosophila mutants discovered a hypnos-2 mutant strain that was later found to be defective in dADAR, the Drosophila gene encoding the A-to-I editing enzyme. This supports the hypothesis that cells and organisms respond to stressful environments by ADAR (adenosine deaminase acting on RNA-mediated RNA editing. Here, we investigated changes in the RNA A-to-I editing frequencies of 30 Drosophila nervous system targets in response to heat shock, a stress acclimatization that requires the dADAR function. To our surprise, most of these nervous system editing targets showed reduced editing. Our results suggest that a change in RNA editing pattern is a mechanism by which organisms acclimate to drastic environmental change. However, how RNA editing confers heat resistance is more complicated and requires further investigation.

  10. Archaea and Bacteria Acclimate to High Total Ammonia in a Methanogenic Reactor Treating Swine Waste

    Directory of Open Access Journals (Sweden)

    Sofia Esquivel-Elizondo

    2016-01-01

    Full Text Available Inhibition by ammonium at concentrations above 1000 mgN/L is known to harm the methanogenesis phase of anaerobic digestion. We anaerobically digested swine waste and achieved steady state COD-removal efficiency of around 52% with no fatty-acid or H2 accumulation. As the anaerobic microbial community adapted to the gradual increase of total ammonia-N (NH3-N from 890±295 to 2040±30 mg/L, the Bacterial and Archaeal communities became less diverse. Phylotypes most closely related to hydrogenotrophic Methanoculleus (36.4% and Methanobrevibacter (11.6%, along with acetoclastic Methanosaeta (29.3%, became the most abundant Archaeal sequences during acclimation. This was accompanied by a sharp increase in the relative abundances of phylotypes most closely related to acetogens and fatty-acid producers (Clostridium, Coprococcus, and Sphaerochaeta and syntrophic fatty-acid Bacteria (Syntrophomonas, Clostridium, Clostridiaceae species, and Cloacamonaceae species that have metabolic capabilities for butyrate and propionate fermentation, as well as for reverse acetogenesis. Our results provide evidence countering a prevailing theory that acetoclastic methanogens are selectively inhibited when the total ammonia-N concentration is greater than ~1000 mgN/L. Instead, acetoclastic and hydrogenotrophic methanogens coexisted in the presence of total ammonia-N of ~2000 mgN/L by establishing syntrophic relationships with fatty-acid fermenters, as well as homoacetogens able to carry out forward and reverse acetogenesis.

  11. Chromatic acclimation and population dynamics of green sulfur bacteria grown with spectrally tailored light

    Science.gov (United States)

    Saikin, Semion K.; Khin, Yadana; Huh, Joonsuk; Hannout, Moataz; Wang, Yaya; Zare, Farrokh; Aspuru-Guzik, Alán; Tang, Joseph Kuo-Hsiang

    2014-05-01

    Living organisms have to adjust to their surrounding in order to survive in stressful conditions. We study this mechanism in one of most primitive creatures - photosynthetic green sulfur bacteria. These bacteria absorb photons very efficiently using the chlorosome antenna complexes and perform photosynthesis in extreme low-light environments. How the chlorosomes in green sulfur bacteria are acclimated to the stressful light conditions, for instance, if the spectrum of light is not optimal for absorption, is unknown. Studying Chlorobaculum tepidum cultures with far-red to near-infrared light-emitting diodes, we found that these bacteria react to changes in energy flow by regulating the amount of light-absorbing pigments and the size of the chlorosomes. Surprisingly, our results indicate that the bacteria can survive in near-infrared lights capturing low-frequency photons by the intermediate units of the light-harvesting complex. The latter strategy may be used by the species recently found near hydrothermal vents in the Pacific Ocean.

  12. Toward systems biology in brown algae to explore acclimation and adaptation to the shore environment.

    Science.gov (United States)

    Tonon, Thierry; Eveillard, Damien; Prigent, Sylvain; Bourdon, Jérémie; Potin, Philippe; Boyen, Catherine; Siegel, Anne

    2011-12-01

    Brown algae belong to a phylogenetic lineage distantly related to land plants and animals. They are almost exclusively found in the intertidal zone, a harsh and frequently changing environment where organisms are submitted to marine and terrestrial constraints. In relation with their unique evolutionary history and their habitat, they feature several peculiarities, including at the level of their primary and secondary metabolism. The establishment of Ectocarpus siliculosus as a model organism for brown algae has represented a framework in which several omics techniques have been developed, in particular, to study the response of these organisms to abiotic stresses. With the recent publication of medium to high throughput profiling data, it is now possible to envision integrating observations at the cellular scale to apply systems biology approaches. As a first step, we propose a protocol focusing on integrating heterogeneous knowledge gained on brown algal metabolism. The resulting abstraction of the system will then help understanding how brown algae cope with changes in abiotic parameters within their unique habitat, and to decipher some of the mechanisms underlying their (1) acclimation and (2) adaptation, respectively consequences of (1) the behavior or (2) the topology of the system resulting from the integrative approach.

  13. Grande Ronde Endemic Spring Chinook Salmon Supplementation Project; Lostine River Operations and Maintenance 2004 Smolt Acclimation and Adult Return Report.

    Energy Technology Data Exchange (ETDEWEB)

    Zollman, Richard L.; Eschler, Russell; Sealey, Shawn [Nez Perce Tribe

    2009-03-31

    The Nez Perce Tribe (NPT), through funding provided by the Bonneville Power Administration (BPA), has implemented a Chinook salmon supplementation program (250,000 smolts) on the Lostine River, a tributary to the Grande Ronde River of Oregon. The Grande Ronde Endemic Spring Chinook Salmon Supplementation project, which involves supplementation of the Upper Grande Ronde River and Catherine Creek in addition to the Lostine River, was established to prevent extirpation and increase the number of threatened Snake River spring/summer Chinook salmon (Oncorhynchus tshawytscha) returning to the Grande Ronde River. This report covers the eighth season (1997-2004) of adult Chinook salmon broodstock collection in the Lostine River and the sixth season (1999-2004) of acclimation of resulting Lostine River progeny. Production of Lostine River spring Chinook salmon smolts currently occurs at Lookingglass Fish Hatchery (LGH). The Lostine River supplementation program utilizes two strategies to obtain egg source for production of smolts for supplementation: captive broodstock and conventional broodstock. The captive broodstock strategy involves (1) capture of natural juvenile spring Chinook salmon smolts from the Lostine River, (2) rearing those to adult and spawning them, and (3) rearing the resultant progeny for eventual acclimation and release back into the Lostine River. The conventional broodstock strategy involves (1) capture of natural and hatchery origin adults returning to the Lostine River, (2) holding those adults and spawning them, and (3) rearing the resultant progency for acclimation and release back into the Lostine River. This report focuses on (1) the trapping and collection of adult spring Chinook salmon that return to the Lostine River, which provides the broodstock source for the conventional strategy and (2) the acclimation and release of juvenile spring Chinook salmon produced from the captive broodstock and conventional broodstock strategies. In 2004

  14. The roles of thermal transient receptor potential channels in thermotactic behavior and in thermal acclimation in the red flour beetle, Tribolium castaneum.

    Science.gov (United States)

    Kim, Hong Geun; Margolies, David; Park, Yoonseong

    2015-05-01

    To survive in variable or fluctuating temperature, organisms should show appropriate behavioral and physiological responses which must be mediated through properly attuned thermal sensory mechanisms. Transient receptor potential channels (TRPs) are a family of cation channels a number of which, called thermo-TRPs, are known to function as thermosensors. We investigated the potential role of thermo-TPRs that have been previously identified in the fruit fly, Drosophila melanogaster, in thermotaxis and thermal acclimation in the red flour beetle, Tribolium castaneum. Phylogenetic analysis of the trp genes showed generally one-to-one orthology between those in D. melanogaster and in T. castaneum, although there are putative gene-losses in two TRP subfamilies of D. melanogaster. With RNA interference (RNAi) of T. castaneum thermo-TRP candidates painless, pyrexia and trpA1, we measured thermal avoidance behavior. RNAi of trpA1 resulted in reduced avoidance of high temperatures, 39 and 42 °C. We also measured the effects of RNAi on heat-induced knockout and death under a short exposure to high temperature (1min at 52 °C) either with or without a 10-min acclimation period at 42 °C. Relatively short exposure to high temperature was enough to induce high temperature thermal acclimation. RNAi of trpA1 led to faster knockout at 52 °C. RNAi of painless showed lower recovery rates from heat-induced knockout after thermal acclimation, and RNAi of pyrexia showed lower long-term survivorship without thermal acclimation. Therefore, we concluded that trpA1 is important in high temperature sensing and also in enhanced tolerance to high-temperature induced knockout; painless plays a role in rapid acclimation to high temperature; and pyrexia functions in protecting beetles from acute heat stress without acclimation.

  15. The temporal and species dynamics of photosynthetic acclimation in flag leaves of rice (Oryza sativa) and wheat (Triticum aestivum) under elevated carbon dioxide

    Energy Technology Data Exchange (ETDEWEB)

    Zhu, J.; Zeng, Q.; Xie, Z.; Tang, H.; Zhu, C. (Chinese Academy of Sciences. State Key Lab. of Soil and Sustainable Agriculture, Institute of Soil Science, Nanjing (China)); Hasegawa, T. (National Institute for Agro-Environmental Sciences. Agro-Meteorology Div., Tsukuba (Japan)); Ziska, L. (Crop Systems and Global Change Lab., Beltsville, MD (United States)); Jia, X. (Chinese Academic of Sciences/Nanjing Botanical Garden Memorial Sun Yat-Sen. Jiangsu Institute of Botany, Nanjing (China))

    2012-07-15

    In this study, we tested for the temporal occurrence of photosynthetic acclimation to elevated [CO{sub 2}] in the flag leaf of two important cereal crops, rice and wheat. In order to characterize the temporal onset of acclimation and the basis for any observed decline in photosynthetic rate, we characterized net photosynthesis, g{sub s}, g{sub m}, C{sub i}/C{sub a}, C{sub i}/C{sub c}, V{sub cmax}, J{sub max}, cell wall thickness, content of Rubisco, cytochrome (Cyt) f, N, chlorophyll and carbohydrate, mRNA expression for rbcL and petA, activity for Rubisco, sucrose phosphate synthase (SPS) and sucrose synthase (SS) at full flag expansion, mid-anthesis and the late grain-filling stage. No acclimation was observed for either crop at full flag leaf expansion. However, at the mid-anthesis stage, photosynthetic acclimation in rice was associated with RuBP carboxylation and regeneration limitations, while wheat only had the carboxylation limitation. By grain maturation, the decline of Rubisco content and activity had contributed to RuBP carboxylation limitation of photosynthesis in both crops at elevated [CO{sub 2}]; however, the sharp decrease of Rubisco enzyme activity played a more important role in wheat. Although an increase in non-structural carbohydrates did occur during these later stages, it was not consistently associated with changes in SPS and SS or photosynthetic acclimation. Rather, over time elevated [CO{sub 2}] appeared to enhance the rate of N degradation and senescence so that by late-grain fill, photosynthetic acclimation to elevated [CO{sub 2}] in the flag leaf of either species was complete. These data suggest that the basis for photosynthetic acclimation with elevated [CO{sub 2}] may be more closely associated with enhanced rates of senescence, and, as a consequence, may be temporally dynamic, with significant species variation. (Author)

  16. Structural lipid changes and Na(+)/K(+)-ATPase activity of gill cells' basolateral membranes during saltwater acclimation in sea lamprey (Petromyzon marinus, L.) juveniles.

    Science.gov (United States)

    Lança, Maria João; Machado, Maria; Ferreira, Ana Filipa; Quintella, Bernardo Ruivo; de Almeida, Pedro Raposo

    2015-11-01

    Seawater acclimation is a critical period for anadromous species and a process yet to be understood in lampreys. Considering that changes in lipid composition of the gill cells' basolateral membranes may disrupt the major transporter Na(+)K(+)-ATPase, the goal of this study was to detect changes at this level during juvenile sea lamprey seawater acclimation. The results showed that saltwater acclimation has a direct effect on the fatty acid composition of gill cells basolateral membrane's phospholipids. When held in full-strength seawater, the fatty acid profile of basolateral membrane's phospholipids suffered a restructure by increasing either saturation or the ratio between oleic acid and eicosapentaenoic acid. Simultaneously, the activity of Na(+)K(+)-ATPase revealed a significant and positive correlation with basolateral membrane's cholesterol content in the presence of highest salinity. Our results pointed out for lipid adjustments involving the functional transporter present on the gill cell basolateral membranes to ensure the role played by branchial Na(+)K(+)-ATPase in ion transport during saltwater acclimation process. The responses observed contributed to the strategy adopted by gill cell's basolateral membranes to compensate for osmotic and ionic stressors, to ensure the success of the process of seawater acclimation associated with the downstream trophic migration of juvenile sea lamprey.

  17. Acclimation of aerobic-activated sludge degrading benzene derivatives and co-metabolic degradation activities of trichloroethylene by benzene derivative-grown aerobic sludge.

    Science.gov (United States)

    Wang, Shizong; Yang, Qi; Bai, Zhiyong; Wang, Shidong; Wang, Yeyao; Nowak, Karolina M

    2015-01-01

    The acclimation of aerobic-activated sludge for degradation of benzene derivatives was investigated in batch experiments. Phenol, benzoic acid, toluene, aniline and chlorobenzene were concurrently added to five different bioreactors which contained the aerobic-activated sludge. After the acclimation process ended, the acclimated phenol-, benzoic acid-, toluene-, aniline- and chlorobenzene-grown aerobic-activated sludge were used to explore the co-metabolic degradation activities of trichloroethylene (TCE). Monod equation was employed to simulate the kinetics of co-metabolic degradation of TCE by benzene derivative-grown sludge. At the end of experiments, the mixed microbial communities grown under different conditions were identified. The results showed that the acclimation periods of microorganisms for different benzene derivatives varied. The maximum degradation rates of TCE for phenol-, benzoic acid-, toluene-, aniline- and chlorobenzene-grown aerobic sludge were 0.020, 0.017, 0.016, 0.0089 and 0.0047 mg g SS(-1) h(-1), respectively. The kinetic of TCE degradation in the absence of benzene derivative followed Monod equation well. Also, eight phyla were observed in the acclimated benzene derivative-grown aerobic sludge. Each of benzene derivative-grown aerobic sludge had different microbial community composition. This study can hopefully add new knowledge to the area of TCE co-metabolic by mixed microbial communities, and further the understanding on the function and applicability of aerobic-activated sludge.

  18. Endocrine systems in juvenile anadromous and landlocked Atlantic salmon (Salmo salar): Seasonal development and seawater acclimation

    Science.gov (United States)

    Nilsen, Tom O.; Ebbesson, Lars O.E.; Kiilerich, P.; Bjornsson, B. Th; Madsen, Steffen S.; McCormick, S.D.; Stefansson, S.O.

    2008-01-01

    The present study compares developmental changes in plasma levels of growth hormone (GH), insulin-like growth factor I (IGF-I) and cortisol, and mRNA levels of their receptors and the prolactin receptor (PRLR) in the gill of anadromous and landlocked Atlantic salmon during the spring parr-smolt transformation (smoltification) period and following four days and one month seawater (SW) acclimation. Plasma GH and gill GH receptor (GHR) mRNA levels increased continuously during the spring smoltification period in the anadromous, but not in landlocked salmon. There were no differences in plasma IGF-I levels between strains, or any increase during smoltification. Gill IGF-I and IGF-I receptor (IGF-IR) mRNA levels increased in anadromous salmon during smoltification, with no changes observed in landlocked fish. Gill PRLR mRNA levels remained stable in both strains during spring. Plasma cortisol levels in anadromous salmon increased 5-fold in May and June, but not in landlocked salmon. Gill glucocorticoid receptor (GR) mRNA levels were elevated in both strains at the time of peak smoltification in anadromous salmon, while mineralocorticoid receptor (MR) mRNA levels remained stable. Only anadromous salmon showed an increase of gill 11??-hydroxysteroid dehydrogenase type-2 (11??-HSD2) mRNA levels in May. GH and gill GHR mRNA levels increased in both strains following four days of SW exposure in mid-May, whereas only the anadromous salmon displayed elevated plasma GH and GHR mRNA after one month in SW. Plasma IGF-I increased after four days in SW in both strains, decreasing in both strains after one month in SW. Gill IGF-I mRNA levels were only increased in landlocked salmon after 4 days in SW. Gill IGF-IR mRNA levels in SW did not differ from FW levels in either strain. Gill PRLR mRNA did not change after four days of SW exposure, and decreased in both strains after one month in SW. Plasma cortisol levels did not change following SW exposure in either strain. Gill GR, 11

  19. Juvenile Coffee Leaves Acclimated to Low Light Are Unable to Cope with a Moderate Light Increase.

    Science.gov (United States)

    Campa, Claudine; Urban, Laurent; Mondolot, Laurence; Fabre, Denis; Roques, Sandrine; Lizzi, Yves; Aarrouf, Jawad; Doulbeau, Sylvie; Breitler, Jean-Christophe; Letrez, Céline; Toniutti, Lucile; Bertrand, Benoit; La Fisca, Philippe; Bidel, Luc P R; Etienne, Hervé

    2017-01-01

    The understorey origin of coffee trees and the strong plasticity of Coffea arabica leaves in relation to contrasting light environments have been largely shown. The adaptability of coffee leaves to changes in light was tested under controlled conditions by increasing the illumination rate on C. arabica var. Naryelis seedlings acclimated to low light conditions and observing leaf responses at three different developmental stages (juvenile, growing and mature). Only mature leaves proved capable of adapting to new light conditions. In these leaves, different major mechanisms were found to contribute to maintaining a good photosynthetic level. With increased illumination, a high photosynthetic response was conserved thanks to fast nitrogen remobilization, as indicated by SPAD values and the photorespiration rate. Efficient photoprotection was accompanied by a great ability to export sucrose, which prevented excessive inhibition of the Calvin cycle by hexose accumulation. In contrast, in younger leaves, increased illumination caused photodamage, observable even after 9 days of treatment. One major finding was that young coffee leaves rely on the accumulation of chlorogenic acids, powerful antioxidant phenolic compounds, to deal with the accumulation of reactive oxygen species rather than on antioxidant enzymes. Due to a lack of efficient photoprotection, a poor ability to export sucrose and inadequate antioxidant protection, younger leaves seemed to be unable to cope with increased illumination. In these leaves, an absence of induced antioxidant enzyme activity was accompanied, in growing leaves, by an absence of antioxidant synthesis or, in juvenile leaves, inefficient synthesis of flavonoids because located in some epidermis cells. These observations showed that coffee leaves, at the beginning of their development, are not equipped to withstand quick switches to higher light levels. Our results confirm that coffee trees, even selected for full sunlight conditions

  20. Head-Down Tilt with Balanced Traction as a Model for Simulating Spinal Acclimation to Microgravity

    Science.gov (United States)

    Ballard, R. E.; Styf, J. R.; Watenpaugh, D. E.; Fechner, K.; Haruna, Y.; Kahan, N. J.; Hargens, A. R.

    1994-01-01

    Astronauts experience total body height increases of 4 to 7 cm in microgravity. Thus, stretching of the spinal cord, nerve roots, and muscular and ligamentous tissues may be responsible for the hyperreflexia, back pain, and muscular atrophy associated with exposure to microgravity. Axial compression of the spine makes 6 deg. head-down tilt (HDT) an unsuitable model for spinal acclimation to microgravity. However, this axial compression may be counteracted by balanced traction consisting of 10% body weight (sin 6 deg. = 0.1) applied to the legs. Six healthy male subjects underwent 3 days each of 60 HDT with balanced traction and horizontal bed rest (HBR), with a 2 week recovery period between treatments. Total body and spine length, lumbar disc height, back pain, erector spinae intramuscular pressure, and ankle joint torque were measured before, during and after each treatment. Total body and spine (processes of L5 - C7) lengths increased significantly more during HDT with balanced traction (22 +/- 8 mm and 25 +/- 8 mm, respectively) than during HBR (16 +/- 4 mm and 14 +/- 9 mm, respectively). Back and leg pain were significantly greater during HDT with balanced traction than during HBR. The distance between the lower end plate of L4 and the upper endplate of S1, as measured by sonography, increased significantly in both treatments to the same degree (2.9 +/- 1.9 mm, HDT with balanced traction; 3.3 +/- 1.5 mm, HBR). Intramuscular pressure of the erector spinae muscles and maximal ankle joint torque were unaltered with both models. While neither model increased height to the magnitude observed in microgravity, HDT with balanced traction may be a better model for simulating the body lengthening and back pain experienced in microgravity.

  1. Photosynthetic and Respiratory Acclimation to Experimental Warming for Four Species in a Tallgrass Prairie Ecosystem

    Institute of Scientific and Technical Information of China (English)

    Xuhui Zhou; Xiaozhong Liu; Linda L. Wallace; Yiqi Luo

    2007-01-01

    Global temperature has been increased by 0.6 ℃ over the past century and is predicted to increase by 1.4-5.8 ℃ by the end of this century. It is unclear what impacts global warming will have on tallgrass species. In the present study, we examined leaf net photosynthetic rate (Pn) and leaf respiration rate in darkness (Rd) of Aster ericoides (L.)Nesom, Ambrosia psilostachya DC., Hellanthus mollis Lam., and Sorghastrum nutans (L.) Nash In response to experimental warming in a tallgrass prairie ecosystem of the Great Plains, USA, in the autumn (fall) of 2000 and through 2001. Warming has been implemented with infrared heaters since 21 November 1999. The Pn increased significantly in spring, decreased in early fall, and did not change in summer and late fall in the four species under warming compared with control. The Rd of the four species increased significantly until mid-summer and then did not change under warming. Measured temperature-response curves of Pn showed that warming increased the optimum temperature of Pn (Topt) by 2.32 and 4.59 ℃ for H. mollis and S. nutans, respectively, in August, whereas there were no changes in May and September, and A. ericoides and A. psilostachya also showed no changes in any of the 3 months. However, Pn at optimum temperature (Popt) showed downregulation in September and no regulation in May and August for all four species. The temperature-response curves of Rd illustrate that the temperature sensitivity of Rd, Q10, was lower in the warmed plots compared with the control plots, except for A. ericoides in August, whereas there were no changes in May and September for all four species. The results of the present study indicate that photosynthetic and respiratory acclimation varies with species and among seasons, occurring in the mid-growing season and not in the early and late growing seasons.

  2. Brain and hepatic Hsp70 protein levels in heat-acclimated broiler chickens during heat stress

    Directory of Open Access Journals (Sweden)

    EN Guerreiro

    2004-12-01

    Full Text Available In the present study we have investigated the effects of heat acclimation on brain and hepatic Hsp70 protein levels and body temperature of broiler chickens in response to gradual heat stress. Two groups of broilers were raised up to 47 days of age under distinct temperature conditions: thermoneutral (TN, according to bird age or hot environmental (HS, 31-33°C. At 46 days of age, the birds reared at high ambient temperature were transferred to thermoneutrality conditions. After 18 h, these birds and the birds reared at thermoneutral temperature were submitted to gradual heat stress in a climatic chamber so that environment temperature was increased from 28 to 40ºC at a rate of 2ºC/h. Colonic temperature was measured using a thermometer sensor probe at each two hours, and hepatic and brain tissues were collected immediately after slaughter in order to assess Hsp70 protein level by Western blotting analysis. The colonic temperatures of birds reared at high temperature increased steeply during the first 2 h of heat stress (1.06ºC/h and more slowly thereafter (0.59ºC/h. Broilers reared at thermoneutral temperature showed a small increase in the first 4 h of heat stress (0.18ºC/h and then colonic temperature increased sharply (0.72ºC/h. Nevertheless, both groups presented similar final colonic temperature by the end of the stress period. Hsp70 levels (ng Hsp70 µg total protein-1 did not change in the liver or brain of the birds reared at high temperature. On the other hand, both liver and brain Hsp70 levels increased significantly during heat stress in the animals reared at thermoneutrality, with a higher expression of this peptide in brain tissue.

  3. Influence of photo- and chromatic acclimation on pigment composition in the sea

    Directory of Open Access Journals (Sweden)

    Roman Majchrowski

    2000-06-01

    field characteristics are due to the photo- and chromatic acclimation of natural populations of marine phytoplankton. These relationships can be applied in models of the coefficients of light absorption by phytoplankton.

  4. Effect of Permissive Dehydration on Induction and Decay of Heat Acclimation, and Temperate Exercise Performance

    Science.gov (United States)

    Neal, Rebecca A.; Massey, Heather C.; Tipton, Michael J.; Young, John S.; Corbett, Jo

    2016-01-01

    Purpose: It has been suggested that dehydration is an independent stimulus for heat acclimation (HA), possibly through influencing fluid-regulation mechanisms and increasing plasma volume (PV) expansion. There is also some evidence that HA may be ergogenic in temperate conditions and that this may be linked to PV expansion. We investigated: (i) the influence of dehydration on the time-course of acquisition and decay of HA; (ii) whether dehydration augmented any ergogenic benefits in temperate conditions, particularly those related to PV expansion. Methods: Eight males [VO2max: 56.9(7.2) mL·kg−1·min−1] undertook two HA programmes (balanced cross-over design), once drinking to maintain euhydration (HAEu) and once with restricted fluid-intake (HADe). Days 1, 6, 11, and 18 were 60 min exercise-heat stress tests [HST (40°C; 50% RH)], days 2–5 and 7–10 were 90 min, isothermal-strain (Tre ~ 38.5°C), exercise-heat sessions. Performance parameters [VO2max, lactate threshold, efficiency, peak power output (PPO)] were determined pre and post HA by graded exercise test (22°C; 55%RH). Results: During isothermal-strain sessions hypohydration was achieved in HADe and euhydration maintained in HAEu [average body mass loss −2.71(0.82)% vs. −0.56(0.73)%, P exercise Tre [−0.30(0.27)°C] and exercise heart rate [−12(15) beats.min−1], increased PV [+7.2(6.4)%] and sweat-loss [+0.25(0.22) L.h−1], P exercise Tre [−0.25(0.19)°C] and exercise heart rate [−3(9) beats.min−1], P 5 days to optimize HA. PMID:27932993

  5. Grande Ronde Endemic Spring Chinook Salmon Supplementation Project; Lostine River Operations and Maintenance 2006 Smolt Acclimation and Adult Return Report.

    Energy Technology Data Exchange (ETDEWEB)

    Zollman, Richard L.; Eschler, Russell; Sealey, Shawn [Nez Perce Tribe

    2009-03-31

    The Nez Perce Tribe (NPT), through funding provided by the Bonneville Power Administration (BPA), has implemented a Chinook salmon supplementation program (250,000 smolts) on the Lostine River, a tributary to the Grande Ronde River of Oregon. The Grande Ronde Endemic Spring Chinook Salmon Supplementation project, which involves supplementation of the Upper Grande Ronde River and Catherine Creek in addition to the Lostine River, was established to prevent extirpation and increase the number of threatened Snake River spring/summer Chinook salmon (Oncorhynchus tshawytscha) returning to the Grande Ronde River. This report covers the tenth season (1997-2006) of adult Chinook salmon broodstock collection in the Lostine River and the eighth season (1999-2006) of acclimation of resulting Lostine River progeny. Production of Lostine River spring Chinook salmon smolts currently occurs at Lookingglass Fish Hatchery (LGH). The Lostine River supplementation program utilizes two strategies to obtain egg source for production of smolts for supplementation: captive broodstock and conventional broodstock. The captive broodstock strategy involves (1) capture of natural juvenile spring Chinook salmon smolts from the Lostine River, (2) rearing those to adult and spawning them, and (3) rearing the resultant progeny for eventual acclimation and release back into the Lostine River. The conventional broodstock strategy involves (1) capture of natural and hatchery origin adults returning to the Lostine River, (2) holding those adults and spawning them, and (3) rearing the resultant progeny for acclimation and release back into the Lostine River. This report focuses on (1) the trapping and collection of adult spring Chinook salmon that return to the Lostine River, which provides the broodstock source for the conventional strategy and (2) the acclimation and release of juvenile spring Chinook salmon produced from the captive broodstock and conventional broodstock strategies In 2006

  6. Grande Ronde Endemic Spring Chinook Salmon Supplementation Project; Lostine River Operations and Maintenance 2003 Smolt Acclimation and Adult Return Report.

    Energy Technology Data Exchange (ETDEWEB)

    Zollman, Richard L.; Eschler, Russell; Sealey, Shawn [Nez Perce Tribe

    2009-03-31

    The Nez Perce Tribe (NPT), through funding provided by the Bonneville Power Administration (BPA), has implemented a Chinook salmon supplementation program (250,000 smolts) on the Lostine River, a tributary to the Grande Ronde River of Oregon. The Grande Ronde Endemic Spring Chinook Salmon Supplementation project, which involves supplementation of the Upper Grande Ronde River and Catherine Creek in addition to the Lostine River, was established to prevent extirpation and increase the number of threatened Snake River spring/summer Chinook salmon (Oncorhynchus tshawytscha) returning to the Grande Ronde River. This report covers the seventh season (1997-2003) of adult Chinook salmon broodstock collection in the Lostine River and the fifth season (1999-2003) of acclimating the resultant progeny. Production of Lostine River spring Chinook salmon smolts currently occurs at Lookingglass Fish Hatchery (LGH). The Lostine River supplementation program utilizes two strategies to obtain egg source for production of smolts for supplementation: captive broodstock and conventional broodstock. The captive broodstock strategy involves (1) capture of natural juvenile spring Chinook salmon smolts from the Lostine River, (2) rearing those to adult and spawning them, and (3) rearing the resultant progeny for eventual acclimation and release back into the Lostine River. The conventional broodstock strategy involves (1) capture of natural and hatchery origin adults returning to the Lostine River, (2) holding those adults and spawning them, and (3) rearing the resultant progeny for acclimation and release back into the Lostine River. This report focuses on (1) the trapping and collection of adult spring Chinook salmon that return to the Lostine River, which provides the broodstock source for the conventional strategy and (2) the acclimation and release of juvenile spring Chinook salmon produced from the captive broodstock and conventional broodstock strategies. In 2003, acclimation of

  7. RNA-Seq Analysis of Sulfur-Deprived Chlamydomonas Cells Reveals Aspects of Acclimation Critical for Cell Survival[W

    Science.gov (United States)

    González-Ballester, David; Casero, David; Cokus, Shawn; Pellegrini, Matteo; Merchant, Sabeeha S.; Grossman, Arthur R.

    2010-01-01

    The Chlamydomonas reinhardtii transcriptome was characterized from nutrient-replete and sulfur-depleted wild-type and snrk2.1 mutant cells. This mutant is null for the regulatory Ser-Thr kinase SNRK2.1, which is required for acclimation of the alga to sulfur deprivation. The transcriptome analyses used microarray hybridization and RNA-seq technology. Quantitative RT-PCR evaluation of the results obtained by these techniques showed that RNA-seq reports a larger dynamic range of expression levels than do microarray hybridizations. Transcripts responsive to sulfur deprivation included those encoding proteins involved in sulfur acquisition and assimilation, synthesis of sulfur-containing metabolites, Cys degradation, and sulfur recycling. Furthermore, we noted potential modifications of cellular structures during sulfur deprivation, including the cell wall and complexes associated with the photosynthetic apparatus. Moreover, the data suggest that sulfur-deprived cells accumulate proteins with fewer sulfur-containing amino acids. Most of the sulfur deprivation responses are controlled by the SNRK2.1 protein kinase. The snrk2.1 mutant exhibits a set of unique responses during both sulfur-replete and sulfur-depleted conditions that are not observed in wild-type cells; the inability of this mutant to acclimate to S deprivation probably leads to elevated levels of singlet oxygen and severe oxidative stress, which ultimately causes cell death. The transcriptome results for wild-type and mutant cells strongly suggest the occurrence of massive changes in cellular physiology and metabolism as cells become depleted for sulfur and reveal aspects of acclimation that are likely critical for cell survival. PMID:20587772

  8. Leaves of the Arabidopsis maltose exporter1 mutant exhibit a metabolic profile with features of cold acclimation in the warm.

    Directory of Open Access Journals (Sweden)

    Sarah J Purdy

    Full Text Available BACKGROUND: Arabidopsis plants accumulate maltose from starch breakdown during cold acclimation. The Arabidopsis mutant, maltose excess1-1, accumulates large amounts of maltose in the plastid even in the warm, due to a deficient plastid envelope maltose transporter. We therefore investigated whether the elevated maltose level in mex1-1 in the warm could result in changes in metabolism and physiology typical of WT plants grown in the cold. PRINCIPAL FINDINGS: Grown at 21 °C, mex1-1 plants were much smaller, with fewer leaves, and elevated carbohydrates and amino acids compared to WT. However, after transfer to 4 °C the total soluble sugar pool and amino acid concentration was in equal abundance in both genotypes, although the most abundant sugar in mex1-1 was still maltose whereas sucrose was in greatest abundance in WT. The chlorophyll a/b ratio in WT was much lower in the cold than in the warm, but in mex1-1 it was low in both warm and cold. After prolonged growth at 4 °C, the shoot biomass, rosette diameter and number of leaves at bolting were similar in mex1-1 and WT. CONCLUSIONS: The mex1-1 mutation in warm-grown plants confers aspects of cold acclimation, including elevated levels of sugars and amino acids and low chlorophyll a/b ratio. This may in turn compromise growth of mex1-1 in the warm relative to WT. We suggest that elevated maltose in the plastid could be responsible for key aspects of cold acclimation.

  9. Deciphering the metabolic changes associated with diapause syndrome and cold acclimation in the two-spotted spider mite Tetranychus urticae.

    Directory of Open Access Journals (Sweden)

    Samira Khodayari

    Full Text Available Diapause is a common feature in several arthropod species that are subject to unfavorable growing seasons. The range of environmental cues that trigger the onset and termination of diapause, in addition to associated hormonal, biochemical, and molecular changes, have been studied extensively in recent years; however, such information is only available for a few insect species. Diapause and cold hardening usually occur together in overwintering arthropods, and can be characterized by recording changes to the wealth of molecules present in the tissue, hemolymph, or whole body of organisms. Recent technological advances, such as high throughput screening and quantification of metabolites via chromatographic analyses, are able to identify such molecules. In the present work, we examined the survival ability of diapausing and non-diapausing females of the two-spotted spider mite, Tetranychus urticae, in the presence (0 or 5°C or absence of cold acclimation. Furthermore, we examined the metabolic fingerprints of these specimens via gas chromatography-mass spectrophotometry (GC-MS. Partial Least Square Discriminant Analysis (PLS-DA of metabolites revealed that major metabolic variations were related to diapause, indicating in a clear cut-off between diapausing and non-diapausing females, regardless of acclimation state. Signs of metabolic depression were evident in diapausing females, with most amino acids and TCA cycle intermediates being significantly reduced. Out of the 40 accurately quantified metabolites, seven metabolites remained elevated or were accumulated in diapausing mites, i.e. cadaverine, gluconolactone, glucose, inositol, maltose, mannitol and sorbitol. The capacity to accumulate winter polyols during cold-acclimation was restricted to diapausing females. We conclude that the induction of increased cold hardiness in this species is associated with the diapause syndrome, rather than being a direct effect of low temperature. Our results

  10. Progressive enhancement in the secretory functions of the digestive system of the rat in the course of cold acclimation.

    Science.gov (United States)

    Harada, E; Kanno, T

    1976-09-01

    1. The secretory function of the exocrine pancreas and the stomach have been studied in the course of cold acclimation of rats that had been fed at an ambient temperature of 1 degree C in a climatic room. 2. The secretory responses of pancreatic enzymes evoked by continuous infusion of pancreozymin (PZ, 2-5 mu./kg. hr) and a rapid single injection of PZ (1.7 mu./kg) reached a maximum in the group of rats fed at 1 degree C for 4 weeks, and fell to the control levels after 8 weeks. The increase in the flow of pancreatic juice evoked by single injection of PZ was maximal at 4 weeks and slightly decreased after 8 weeks. 3. The insulin (3-0 i.u./kg) evoked secretion of pancreatic enzymes gradually increased after cold exposure, reached a maximum at 4 weeks and fell to the control levels after 8 weeks. The flow of pancreatic juice after insulin injection was almost the same in every group throughout the course of cold exposure. 4. The ratio of amylase to the total amount of the protein in the pancreatic juice decreased abruptly, in contrast to an increase in the ratio of protease in the process of cold acclimation. The change in the ratio of enzyme activity in the pancreatic juice may reflect parallel changes in enzyme activity in the exocrine pancreas. 5. The gastric secretion in response to insulin and bile secretion in the group fed at 1 degree C for 7 weeks was significantly higher than that in the control group. 6. It was thus concluded that the secretory activities of digestive system were enhanced by prolonged cold exposure and then returned to control level, and that the activites of the pancreatic enzymes were altered in the process of cold acclimation in rats.

  11. The coordination of gene expression within photosynthesis pathway for acclimation of C4 energy crop Miscanthus lutarioriparius

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    Shilai eXing

    2016-02-01

    Full Text Available As a promising candidate for the second-generation C4 energy crop, Miscanthus lutarioriparius has well acclimated to the water-limited and high-light Loess Plateau in China by improving photosynthesis rate and water use efficiency (WUE compared to its native habitat along Yangtze River. Photosynthetic genes were demonstrated as one major category of the candidate genes underlying the physiological superiority. To further study how photosynthetic genes interact to improve the acclimation potential of M. lutarioriparius, population expression patterns within photosynthesis pathway were explored between one mild environment and one harsh environment. We found that 108 transcripts in assembled transcriptome of M. lutarioriparius were highly similar to genes in three Kyoto Encyclopedia of Genes and Genomes (KEGG photosynthesis pathways of sorghum and maize. Phylogenetic analyses using sorghum, maize, rice and Arabidopsis genes of dark reaction identified 23 orthologs and 30 paralogs of M. lutarioriparius photosynthetic genes. These genes were also clustered into two kinds of expression pattern. 87% of transcripts in dark reaction were up-regulated and all 14 chloroplast-encoded transcripts in light reaction increased degradation in the harsh environment compared to the mild environment. Moreover, 80.8 % of photosynthetic transcripts were coordinated at transcription level under the two environments. Interestingly, LHCI and PSI were significantly correlated with F-ATPase and C4 cycle. Overall, this study indicates the coordinated expression between cyclic electron transport (consisting of LHCI, PSI and ATPase and CO2-concentrating mechanism (C4 cycle could account for photosynthesis plasticity on M. lutarioriparius acclimation potential.

  12. Phosphorylation dependent and independent regulation of Helicobacter pylori acid acclimation by the ArsRS two-component system

    Science.gov (United States)

    Marcus, Elizabeth A.; Sachs, George; Wen, Yi; Scott, David R.

    2015-01-01

    Background The pH sensitive Helicobacter pylori ArsRS two-component system (TCS) aids survival of this neutralophile in the gastric environment by directly sensing and responding to environmental acidity. ArsS is required for acid-induced trafficking of urease and its accessory proteins to the inner membrane, allowing rapid, urea-dependent cytoplasmic and periplasmic buffering. Expression of ArsR, but not its phosphorylation, is essential for bacterial viability. The aim of this study is to characterize the roles of ArsS and ArsR in the response of H. pylori to acid. Materials and Methods Wildtype H. pylori and an arsR(D52N) phosphorylation deficient strain were incubated at acidic or neutral pH. Gene and protein expression, survival, membrane trafficking of urease proteins, urease activity, and internal pH were studied. Results Phosphorylation of ArsR is not required for acid survival. ArsS-driven trafficking of urease proteins to the membrane in acid, required for recovery of internal pH, is independent of ArsR phosphorylation. ArsR phosphorylation increases expression of the urease gene cluster, and the loss of negative feedback in a phosphorylation deficient mutant leads to an increase in total urease activity. Conclusions ArsRS has a dual function in acid acclimation: regulation of urease trafficking to UreI at the cytoplasmic membrane, driven by ArsS, and regulation of urease gene cluster expression, driven by phosphorylation of ArsR. ArsS and ArsR work through phosphorylation dependent and independent regulatory mechanisms to impact acid acclimation and allow gastric colonization. Furthering understanding of the intricacies of acid acclimation will impact the future development of targeted, non-antibiotic treatment regimens. PMID:25997502

  13. Re-acclimation performance and microbial characteristics of a thermophilic biofilter for NOx removal from flue gas.

    Science.gov (United States)

    Zhang, Shihan; Chen, Han; Xia, Yinfeng; Zhao, Jingkai; Liu, Nan; Li, Wei

    2015-08-01

    Currently, a novel chemical absorption-biological reduction (CABR) integrated process, employing Fe(II)EDTA as a solvent, is being under development to reduce the cost of NOx removal from flue gas. In this work, the NO removal profile, re-acclimation performance, and microbial characteristics in a thermophilic biofilter were investigated at the conditions typical to CABR process. The biofilter comprised of four layers of packing material with a surface area of 1200 m(2) m(-3). Experimental results revealed that the biofilter could remove 95 % of the fed NO at typical flue gas conditions. As the gas residence time varied from 90 to 15 s, the NO removal efficiency decreased from 100 to 56.5 % due to the NO mass transfer limitation. The longer period of the biofilter shutdown required more time for its re-acclimation. For example, after 8-day shutdown, the biofilter was re-acclimated in 32 h. Denaturing gradient gel electrophoresis analysis of PCR-amplified product showed that Pseudomonas, a group of denitrifier, was dominant in the biofilter. Because the Pseudomonas was abundant at the bottom layer of packed-bed, the bottom layer contributed to 60-70 % of the total NO removal. In addition, Pseudomonas gradually faded away along the gas flow path from the bottom to the top of biofilter, resulting in a significant decrease in NO removal at the other three packed-bed layers. These observed results will provide the process engineering and scale-up data with respect to the biofilter operations to help advance the CABR process to pilot-scale testing.

  14. Changes in Osmotic Pressure and Mucilage during Low-Temperature Acclimation of Opuntia ficus-indica 1

    Science.gov (United States)

    Goldstein, Guillermo; Nobel, Park S.

    1991-01-01

    Opuntia ficus-indica, a Crassulacean acid metabolism plant cultivated for its fruits and cladodes, was used to examine chemical and physiological events accompanying low-temperature acclimation. Changes in osmotic pressure, water content, low molecular weight solutes, and extracellular mucilage were monitored in the photosynthetic chlorenchyma and the water-storage parenchyma when plants maintained at day/night air temperatures of 30/20°C were shifted to 10/0°C. An increase in osmotic pressure of 0.13 megapascal occurred after 13 days at 10/0°C. Synthesis of glucose, fructose, and glycerol accounted for most of the observed increase in osmotic pressure during the low-temperature acclimation. Extracellular mucilage and the relative apoplastic water content increased by 24 and 10%, respectively, during exposure to low temperatures. These increases apparently favor the extracellular nucleation of ice closer to the equilibrium freezing temperature for plants at 10/0°C, which could make the cellular dehydration more gradual and less damaging. Nuclear magnetic resonance studies helped elucidate the cellular processes during ice formation, such as those revealed by changes in the relaxation times of two water fractions in the chlorenchyma. The latter results suggested a restricted mobility of intracellular water and an increased mobility of extracellular water for plants at 10/0°C compared with those at 30/20°C. Increased mobility of extracellular water could facilitate extracellular ice growth and thus delay the potentially lethal intracellular freezing during low-temperature acclimation. PMID:16668536

  15. Effects of acclimation on the toxicity of stream water contaminated with zinc and cadmium to juvenile cutthroat trout

    Science.gov (United States)

    Harper, D.D.; Farag, A.M.; Brumbaugh, W.G.

    2008-01-01

    We investigated the influence of acclimation on results of in situ bioassays with cutthroat trout in metal-contaminated streams. Cutthroat trout (Oncorhynchus clarki) were held for 21 days (1) in live containers at a reference or "clean" site having dissolved metals near detection limits (0.01 ??g/L cadmium [Cd] and 2.8 ??g/L zinc [Zn]; hardness 32 mg/L as CaCO3) and (2) at a site in a mining-impacted watershed having moderately increased metals (0.07 ??g/L Cd and 38 to 40 ??g/L Zn; hardness 50 mg/L as CaCO3). The 96-hour survival of each treatment group was then tested in situ at five sites from September 5 to 9, 2002, and each group exhibited a range of metal concentrations (0.44 to 39 ??g/L arsenic [As], 0.01 to 2.2 ??g/L Cd, and 0.49 to 856 ??g/L Zn). Survival was 100% at three sites for both treatments. However, a higher percentage of metal-acclimated fish survived at the site with the second highest concentrations of Cd and Zn (0.90 and 238 ??g/L, respectively) compared with fish acclimated at the reference site (100% vs. 55%, respectively). Survival was 65% for acclimated fish and 0% for metal-nai??ve fish at the site with the largest metal concentrations (2.2 ??g/L Cd and 856 ??g/L Zn). Water collected from the site with the largest concentrations of dissolved metals (on October 30, 2002) was used in a laboratory serial dilution to determine 96-hour LC50 values. The 96-hour LC50 estimates of nai??ve fish during the in situ and laboratory experiments were similar (0.60 ??g Cd/L and 226 ??g Zn/L for in situ and 0.64 ??g Cd/L and 201 ??g Zn/L for laboratory serial dilutions). However, mortality of nai??ve cutthroat trout tested under laboratory conditions was more rapid in dilutions of 100%, 75%, and 38% site water than in situ experiments. ?? 2007 Springer Science+Business Media, LLC.

  16. The impact of cold acclimation and hibernation on antioxidant defenses in the ground squirrel (Spermophilus citellus): an update.

    Science.gov (United States)

    Vucetic, Milica; Stancic, Ana; Otasevic, Vesna; Jankovic, Aleksandra; Korac, Aleksandra; Markelic, Milica; Velickovic, Ksenija; Golic, Igor; Buzadzic, Biljana; Storey, Kenneth B; Korac, Bato

    2013-12-01

    Any alteration in oxidative metabolism is coupled with a corresponding response by an antioxidant defense (AD) in appropriate subcellular compartments. Seasonal hibernators pass through circannual metabolic adaptations that allow them to either maintain euthermy (cold acclimation) or enter winter torpor with body temperature falling to low values. The present study aimed to investigate the corresponding pattern of AD enzyme protein expressions associated with these strategies in the main tissues involved in whole animal energy homeostasis: brown and white adipose tissues (BAT and WAT, respectively), liver, and skeletal muscle. European ground squirrels (Spermophilus citellus) were exposed to low temperature (4 ± 1 °C) and then divided into two groups: (1) animals fell into torpor (hibernating group) and (2) animals stayed active and euthermic for 1, 3, 7, 12, or 21 days (cold-exposed group). We examined the effects of cold acclimation and hibernation on the tissue-dependent protein expression of four enzymes which catalyze the two-step detoxification of superoxide to water: superoxide dismutase 1 and 2 (SOD 1 and 2), catalase (CAT), and glutathione peroxidase (GSH-Px). The results showed that hibernation induced an increase of AD enzyme protein expressions in BAT and skeletal muscle. However, AD enzyme contents in liver were largely unaffected during torpor. Under these conditions, different WAT depots responded by elevating the amounts of specific enzymes, as follows: SOD 1 in retroperitoneal WAT, GSH-Px in gonadal WAT, and CAT in subcutaneous WAT. Similar perturbations of AD enzymes contents were seen in all tissues during cold acclimation, often in a time-dependent manner. It can be concluded that BAT and muscle AD capacity undergo the most dramatic changes during both cold acclimation and hibernation, while liver is relatively unaffected by either condition. Additionally, this study provides a basis for further metabolic study that will illuminate the causes

  17. Acclimation, adaptation, traits and trade-offs in plankton functional type models – seeking clarity in terminology

    DEFF Research Database (Denmark)

    Flynn, Kevin J.; St. John, Michael; Raven, John A.

    2015-01-01

    We propose definitions in terminology to enhance ongoing collaborations between biologists and modellers on plankton ecology. Organism “functional type” should refer to commonality in ecology not biogeochemistry; the latter is largely an emergent property of the former, while alignment with ecology...... is also consistent with usage in terrestrial science. Adaptation should be confined, as in genetics, to consideration of species inter-generational change; most socalled “adaptive” plankton models are thus acclimative, modifying vital rates in response to stimuli. Trait trade-off approaches should ideally...

  18. Natural Resources Containing Arbutin. Determination of Arbutin in the Leaves of Bergenia crassifolia (L. Fritsch. acclimated in Romania

    Directory of Open Access Journals (Sweden)

    Carmen POP

    2009-06-01

    Full Text Available Bergenia crassifolia (L. Fritsch. is cited in literature as being one of the richest in arbutin (15-20%, an important pharmaceutical substance with disinfecting properties (in genitourinary diseases and also depigmentation properties (skin whitening agent. The aim of this study consisted in determination of arbutin content in leaves of Bergenia crassifolia acclimated in Romania. The optimum parameters for the extraction of arbutin and the dynamics of the accumulation of arbutin in Bergenia crassifolia leaves during the four seasons were also studied. The content of arbutin varied between 17.44% and 22.59% dry weight, values which are similar to those found in literature

  19. Affective Urbanism

    DEFF Research Database (Denmark)

    Samson, Kristine

    Urban design and architecture are increasingly used as material and affective strategies for setting the scene, for manipulation and the production of urban life: The orchestration of atmospheres, the framing and staging of urban actions, the programming for contemplation, involvement, play, expe...... affects can be choreographed and designed intentionally or whether it arises from unpredictable circumstances within urbanity itself....

  20. Affective Maps

    DEFF Research Database (Denmark)

    Salovaara-Moring, Inka

    of environmental knowledge production. It uses InfoAmazonia, the databased platform on Amazon rainforests, as an example of affective geo-visualization within information mapping that enhances embodiment in the experience of the information. Amazonia is defined as a digitally created affective (map)space within...

  1. Effects of Cold Acclimation on Several Enzyme Activities in Euonymus radicans 'Emorald & Gold' and Its Relation to Semi-lethal Temperature

    Institute of Scientific and Technical Information of China (English)

    Guo Huihong; Gao Shumin; Zhao Fengjun; Li Fenglan

    2004-01-01

    The changes in activities of superoxide dismutase (SOD), peroxidase (POD) and ATPase in the leaves of Euonymus radicans were studied when seedlings were cold-acclimated (at 4 ℃) for 1 week, 2 weeks, 3 weeks and then treated for 1 d under low temperature stress (at -5 ℃). The semi-lethal temperatures of acclimated and unacclimated seedlings were also investigated. The results indicated that the activities of the three enzymes in the leaves of the seedlings treated at 4 ℃ for 1, 2 and 3 weeks were all higher than those of unacclimated seedings (treated at 22 ℃ as controls). The activities of SOD and POD increased continuously with the prolongation of the time of cold acclimation, but stepped up to summits then down to the levels of the controls. The activities of SOD culminated at the first week, and the activities of POD at the second week. When acclimated and unacclimated seedlings were both treated at -5 ℃ for 1 d, the activities of the three enzymes in the leaves of acclimated seedlings were a little lower than those before stress, but higher than those of the controls. Moreover, the decrease rate of enzyme activities was greatly lower than that of the controls. The results showed that cold acclimation could enhance the stability of the three enzymes in the leaves of seedlings under low temperature stress; the semi-lethal temperature was -19.1 ℃ when the seedlings were treated at 4 ℃ for 3 weeks, but it was -5.4 ℃ when the seedlings were treated at 22 ℃. The decline of the semi-lethal temperature caused by the adaptive changes of enzyme activities was one of the foundations of enhancing the cold tolerance.

  2. Effects of temperature and thermal acclimation on locomotor performance of Macrobiotus hufelandi Schultze (Tardigrada: Macrobiotidae)%温度和热驯化对胡氏大生熊虫运动行为的影响

    Institute of Scientific and Technical Information of China (English)

    李晓晨; 王立志

    2005-01-01

    The beneficial acclimation hypothesis (BAH) predicts that animals acclimated to a particular temperature have enhanced performance or fitness at that temperature in comparison with animals acclimated to other temperatures. The BAH has been tested by a variety of empirical examinations, and was rejected by some of them. In order to provide new evidences for the BAH, the effects of acute and acclimation temperature (AT) on locomotor performance of Macrobiotus hufelandi (Tardigrada: Macrobiotidae) were investigated. The tardigrades were collected from Nanwutai, Qinling Mountains which traverse from west to east in central China. The subjects were acclimated to either 2℃ or 22℃ for 2 weeks. The animal was transferred onto a frosted slide and allowed to walk freely at the performance temperature (PT) 2℃ or 22℃. Only one individual was tested per test bout, which lasted from three to five minutes. To avoid occurrence of thermal acclimation effect, the standard adaptation time was limited to 1.5 min. Each subject was tested for once at the same PT, and was tested only at one PT. A total of 25 individuals were tested and measured at the same PT. The locomotor performance of the animals was recorded with a digital video camera mounted on a microscope at 4×10 amplification and replayed on a PC. Every subject was identified. Walking speed (WS) and percentage of time moving (PTM) at both PTs (2℃ or 22℃) were selected as the rate parameters of locomotor performance. The two-way repeated measures ANOVA with a significance level of α= 0.05 and Duncan multiple range test were used to analyze the data. WS of the animals acclimated to and tested at the same temperatures was significantly faster than that for animals acclimated to and tested at the different temperatures, similarly, PTM of the animals acclimated to 22℃ and tested at 22℃ was significantly greater than PTM of animals acclimated to 22℃ and tested at 2℃, which indicated that the animals acclimated

  3. Isolation of intact and pure chloroplasts from leaves of Arabidopsis thaliana plants acclimated to low irradiance for studies on Rubisco regulation

    Directory of Open Access Journals (Sweden)

    Magda Grabsztunowicz

    2012-11-01

    Full Text Available A protocol is presented for low-cost and fast isolation of intact and pure chloroplasts from leaves of plants acclimated to low irradiance. The protocol is based on a differential centrifugation of cleared leaf homogenate and omits a centrifugation on Percoll gradient step. The intactness and purity of the chloroplasts isolated from leaves of low irradiance-acclimated plants by using this protocol (confirmed by phase contrast microscopy as well as enzymatic and immunological approaches allows plausible studies on low irradiance-dependent Rubisco regulation.

  4. Pre-anthesis high-temperature acclimation alleviates damage to the flag leaf caused by post-anthesis heat stress in wheat

    DEFF Research Database (Denmark)

    Wang, Xiao; Cai, Jian; Jian, Dong

    2011-01-01

    The objective of this study was to investigate the effect of pre-anthesis high-temperature acclimation on leaf physiology of winter wheat in response to post-anthesis heat stress. The results showed that both pre- and post-anthesis heat stresses significantly depressed flag leaf photosynthesis......, the results indicated that pre-anthesis high-temperature acclimation could effectively alleviate the photosynthetic and oxidative damage caused by post-anthesis heat stress in wheat flag leaves, which was partially attributable to modifications in the expression of the photosythesis-responsive and antioxidant...

  5. Interactive effect of high environmental ammonia and nutritional status on ecophysiological performance of European sea bass (Dicentrarchus labrax) acclimated to reduced seawater salinities

    OpenAIRE

    Sinha, A.K.; Rasoloniriana, R.; Dasan, A.F.; Pipralia, N.; R. Blust; De Boeck, G.

    2015-01-01

    We investigated the interactive effect of ammonia toxicity, salinity challenge and nutritional status on the ecophysiological performance of European sea bass (Dicentrarchus labrax). Fish were progressively acclimated to normal seawater (32 ppt), to brackish water (20 ppt and 10 ppt) and to hyposaline water (2.5 ppt). Following acclimation to different salinities for two weeks, fish were exposed to high environmental ammonia (HEA, 20 mg/L ~1.18 mM representing 50% of 96 h LC50 value for ammon...

  6. Alterations in mitochondrial electron transport system activity in response to warm acclimation, hypoxia-reoxygenation and copper in rainbow trout, Oncorhynchus mykiss

    Energy Technology Data Exchange (ETDEWEB)

    Sappal, Ravinder [Department of Pathology and Microbiology, Atlantic Veterinary College, University of Prince Edward Island, Charlottetown, PE, C1A 4P3 (Canada); Department of Biomedical Sciences, Atlantic Veterinary College, University of Prince Edward Island, Charlottetown, PE, C1A 4P3 (Canada); MacDougald, Michelle [Faculty of Medicine, Memorial University of Newfoundland, Health Sciences Centre, Prince Philip Drive, St. John’s, NL, A1B 3V6 (Canada); Fast, Mark [Department of Pathology and Microbiology, Atlantic Veterinary College, University of Prince Edward Island, Charlottetown, PE, C1A 4P3 (Canada); Stevens, Don [Department of Biomedical Sciences, Atlantic Veterinary College, University of Prince Edward Island, Charlottetown, PE, C1A 4P3 (Canada); Kibenge, Fred [Department of Pathology and Microbiology, Atlantic Veterinary College, University of Prince Edward Island, Charlottetown, PE, C1A 4P3 (Canada); Siah, Ahmed [British Columbia Centre for Aquatic Health Sciences, 871A Island Highway, Campbell River, BC, V9W 2C2 (Canada); Kamunde, Collins, E-mail: ckamunde@upei.ca [Department of Biomedical Sciences, Atlantic Veterinary College, University of Prince Edward Island, Charlottetown, PE, C1A 4P3 (Canada)

    2015-08-15

    Highlights: • Sequential inhibition and activation allows assessment of multiple segments of the electron transport system. • Warm acclimation and hypoxia-reoxygenation have global effects on the electron transport system. • Warm acclimation and hypoxia-reoxygenation sensitize the electron transport system to copper. • Thermal stress, hypoxia-reoxygenation and copper act additively to impair mitochondrial function. - Abstract: Fish expend significant amounts of energy to handle the numerous potentially stressful biotic and abiotic factors that they commonly encounter in aquatic environments. This universal requirement for energy singularizes mitochondria, the primary cellular energy transformers, as fundamental drivers of responses to environmental change. Our study probed the interacting effects of thermal stress, hypoxia-reoxygenation (HRO) and copper (Cu) exposure in rainbow trout to test the prediction that they act jointly to impair mitochondrial function. Rainbow trout were acclimated to 11 (controls) or 20 °C for 2 months. Liver mitochondria were then isolated and their responses in vitro to Cu (0–20 μM) without and with HRO were assessed. Sequential inhibition and activation of mitochondrial electron transport system (ETS) enzyme complexes permitted the measurement of respiratory activities supported by complex I–IV (CI–IV) in one run. The results showed that warm acclimation reduced fish and liver weights but increased mitochondrial protein indicating impairment of energy metabolism, increased synthesis of defense proteins and/or reduced liver water content. Whereas acute rise (11 → 20 °C) in temperature increased mitochondrial oxidation rates supported by CI–IV, warm acclimation reduced the maximal (state 3) and increased the basal (state 4) respiration leading to global uncoupling of oxidative phosphorylation (OXPHOS). HRO profoundly inhibited both maximal and basal respiration rates supported by CI–IV, reduced RCR for all except

  7. Acclimation of photosynthesis to elevated CO sub 2 in five C sub 3 species. [Chenopodium album, Phaseolus vulgaris, Solanum tuberosum, Solanum melongena, Brassica oleracea

    Energy Technology Data Exchange (ETDEWEB)

    Sage, R.F. (Univ. of Georgia, Athens (USA)); Sharkey, T.D. (Univ. of Wisconsin, Madison (USA)); Seemann, J.R. (Univ. of Nevada, Reno (USA))

    1989-02-01

    The effect of long-term (weeks to months) CO{sub 2} enhancement on (a) the gas-exchange characteristics, (b) the content and activation state of ribulose-1,5-bisphosphate carboxylase (rubisco), and (c) leaf nitrogen, chlorophyll, and dry weight per area were studied in five C{sub 3} species (Chenopodium album, Phaseolus vulgaris, Solanum tuberosum, Solanum melongena, and Brassica oleracea) grown at CO{sub 2} partial pressures of 300 or 900 to 1000 microbars. Long-term exposure to elevated CO{sub 2} affected the CO{sub 2} response of photosynthesis in one of three ways: (a) the initial slope of the CO{sub 2} response was unaffected, but the photosynthetic rate at high CO{sub 2} increased (S. tuberosum); (b) the initial slope decreased but the CO{sub 2}-saturated rate of photosynthesis decreased (B. oleracea, S. melongena). In all five species, growth at high CO{sub 2} increased the extent to which photosynthesis was stimulated following a decrease in the partial pressure of O{sub 2} or an increase in measurement CO{sub 2} above 600 microbars. This stimulation indicates that a limitation on photosynthesis by the capacity to regenerate orthophosphate was reduced or absent after acclimation to high CO{sub 2}. Leaf nitrogen per area either increased (S. tuberosum, S. melongena) or was little changed by CO{sub 2} enhancement. The content of rubisco was lower in only two of the fives species, yet its activation state was 19% to 48% lower in all five species following long-term exposure to high CO{sub 2}. These results indicate that during growth in CO{sub 2}-enriched air, leaf rubisco content remains in excess of that required to support the observed photosynthetic rates.

  8. Insights from the cold transcriptome and metabolome of Dendrobium officinale: global reprogramming of metabolic and gene regulation networks during cold acclimation

    Directory of Open Access Journals (Sweden)

    Zhi-Gang Wu

    2016-11-01

    Full Text Available Plant cold acclimation (CA is a genetically complex phenomenon involving gene regulation and expression. Little is known about the cascading pattern of gene regulatroy network and the link between genes and metabolites during CA. Dendrobium officinale (DOKM is an important medicinal and ornamental plant and hypersensitive to low temperature. Here, we used the large scale metabolomic and transcriptomic technologies to reveal the response to CA in DOKM seedlings based on the physiological profile analyses. Lowering temperature from 4 oC to -2 oC resulted in significant increase(P<0.01)in antioxidant activities and electrolyte leakage during 24 h. The fitness CA piont of 0 oC and control (20 oC during 20 h were firstly obtained according to physiological analyses. Subsequently, massive transcriptome and metabolome reprogramming occurred during CA. The gene to metabolite network demonstrated that the CA associated processes are highly energy demanding through activating hydrolysis of sugars, amino acids catabolism and citrate cycle. The expression levels of 2,767 genes were significantly affected by CA, including 153-fold upregulation of CBF transcription factor, 56-fold upregulation of MAPKKK16 protein kinase. Moreover, the gene interaction and regulation network analysis revealed that the CA as an active process, was regulated at the transcriptional, post-transcriptional, translational and post-translational levels. Our findings highligted a comprehensive regulatory mechanism including cold signal transduction, transcriptional regulation and gene expression, which contributes a deeper understanding of the highly complex regulatory program during CA in DOKM. Some marker genes identified in DOKM seedlings will allow us to understand the role of each individual during CA by further functional analyses.

  9. Insights from the Cold Transcriptome and Metabolome of Dendrobium officinale: Global Reprogramming of Metabolic and Gene Regulation Networks during Cold Acclimation.

    Science.gov (United States)

    Wu, Zhi-Gang; Jiang, Wu; Chen, Song-Lin; Mantri, Nitin; Tao, Zheng-Ming; Jiang, Cheng-Xi

    2016-01-01

    Plant cold acclimation (CA) is a genetically complex phenomenon involving gene regulation and expression. Little is known about the cascading pattern of gene regulatroy network and the link between genes and metabolites during CA. Dendrobium officinale (DOKM) is an important medicinal and ornamental plant and hypersensitive to low temperature. Here, we used the large scale metabolomic and transcriptomic technologies to reveal the response to CA in DOKM seedlings based on the physiological profile analyses. Lowering temperature from 4 to -2°C resulted in significant increase (P < 0.01) in antioxidant activities and electrolyte leakage (EL) during 24 h. The fitness CA piont of 0°C and control (20°C) during 20 h were firstly obtained according to physiological analyses. Subsequently, massive transcriptome and metabolome reprogramming occurred during CA. The gene to metabolite network demonstrated that the CA associated processes are highly energy demanding through activating hydrolysis of sugars, amino acids catabolism and citrate cycle. The expression levels of 2,767 genes were significantly affected by CA, including 153-fold upregulation of CBF transcription factor, 56-fold upregulation of MAPKKK16 protein kinase. Moreover, the gene interaction and regulation network analysis revealed that the CA as an active process, was regulated at the transcriptional, post-transcriptional, translational and post-translational levels. Our findings highligted a comprehensive regulatory mechanism including cold signal transduction, transcriptional regulation, and gene expression, which contributes a deeper understanding of the highly complex regulatory program during CA in DOKM. Some marker genes identified in DOKM seedlings will allow us to understand the role of each individual during CA by further functional analyses.

  10. Insights from the Cold Transcriptome and Metabolome of Dendrobium officinale: Global Reprogramming of Metabolic and Gene Regulation Networks during Cold Acclimation

    Science.gov (United States)

    Wu, Zhi-Gang; Jiang, Wu; Chen, Song-Lin; Mantri, Nitin; Tao, Zheng-Ming; Jiang, Cheng-Xi

    2016-01-01

    Plant cold acclimation (CA) is a genetically complex phenomenon involving gene regulation and expression. Little is known about the cascading pattern of gene regulatroy network and the link between genes and metabolites during CA. Dendrobium officinale (DOKM) is an important medicinal and ornamental plant and hypersensitive to low temperature. Here, we used the large scale metabolomic and transcriptomic technologies to reveal the response to CA in DOKM seedlings based on the physiological profile analyses. Lowering temperature from 4 to –2°C resulted in significant increase (P antioxidant activities and electrolyte leakage (EL) during 24 h. The fitness CA piont of 0°C and control (20°C) during 20 h were firstly obtained according to physiological analyses. Subsequently, massive transcriptome and metabolome reprogramming occurred during CA. The gene to metabolite network demonstrated that the CA associated processes are highly energy demanding through activating hydrolysis of sugars, amino acids catabolism and citrate cycle. The expression levels of 2,767 genes were significantly affected by CA, including 153-fold upregulation of CBF transcription factor, 56-fold upregulation of MAPKKK16 protein kinase. Moreover, the gene interaction and regulation network analysis revealed that the CA as an active process, was regulated at the transcriptional, post-transcriptional, translational and post-translational levels. Our findings highligted a comprehensive regulatory mechanism including cold signal transduction, transcriptional regulation, and gene expression, which contributes a deeper understanding of the highly complex regulatory program during CA in DOKM. Some marker genes identified in DOKM seedlings will allow us to understand the role of each individual during CA by further functional analyses. PMID:27877182

  11. RNA-seq transcriptome profiling reveals that Medicago truncatula nodules acclimate N2 fixation before emerging P deficiency reaches the nodules

    Science.gov (United States)

    Cabeza, Ricardo A.; Liese, Rebecca; Lingner, Annika; von Stieglitz, Ilsabe; Neumann, Janice; Salinas-Riester, Gabriela; Pommerenke, Claudia; Dittert, Klaus; Schulze, Joachim

    2014-01-01

    Legume nodules are plant tissues with an exceptionally high concentration of phosphorus (P), which, when there is scarcity of P, is preferentially maintained there rather than being allocated to other plant organs. The hypothesis of this study was that nodules are affected before the P concentration in the organ declines during whole-plant P depletion. Nitrogen (N2) fixation and P concentration in various organs were monitored during a whole-plant P-depletion process in Medicago truncatula. Nodule gene expression was profiled through RNA-seq at day 5 of P depletion. Until that point in time P concentration in leaves reached a lower threshold but was maintained in nodules. N2-fixation activity per plant diverged from that of fully nourished plants beginning at day 5 of the P-depletion process, primarily because fewer nodules were being formed, while the activity of the existing nodules was maintained for as long as two weeks into P depletion. RNA-seq revealed nodule acclimation on a molecular level with a total of 1140 differentially expressed genes. Numerous genes for P remobilization from organic structures were increasingly expressed. Various genes involved in nodule malate formation were upregulated, while genes involved in fermentation were downregulated. The fact that nodule formation was strongly repressed with the onset of P deficiency is reflected in the differential expression of various genes involved in nodulation. It is concluded that plants follow a strategy to maintain N2 fixation and viable leaf tissue as long as possible during whole-plant P depletion to maintain their ability to react to emerging new P sources (e.g. through active P acquisition by roots). PMID:25151618

  12. Limited acclimation in leaf anatomy to experimental drought in tropical rainforest trees.

    Science.gov (United States)

    Binks, Oliver; Meir, Patrick; Rowland, Lucy; da Costa, Antonio Carlos Lola; Vasconcelos, Steel Silva; de Oliveira, Alex Antonio Ribeiro; Ferreira, Leandro; Mencuccini, Maurizio

    2016-12-01

    Dry periods are predicted to become more frequent and severe in the future in some parts of the tropics, including Amazonia, potentially causing reduced productivity, higher tree mortality and increased emissions of stored carbon. Using a long-term (12 year) through-fall exclusion (TFE) experiment in the tropics, we test the hypothesis that trees produce leaves adapted to cope with higher levels of water stress, by examining the following leaf characteristics: area, thickness, leaf mass per area, vein density, stomatal density, the thickness of palisade mesophyll, spongy mesophyll and both of the epidermal layers, internal cavity volume and the average cell sizes of the palisade and spongy mesophyll. We also test whether differences in leaf anatomy are consistent with observed differential drought-induced mortality responses among taxa, and look for relationships between leaf anatomy, and leaf water relations and gas exchange parameters. Our data show that trees do not produce leaves that are more xeromorphic in response to 12 years of soil moisture deficit. However, the drought treatment did result in increases in the thickness of the adaxial epidermis (TFE: 20.5 ± 1.5 µm, control: 16.7 ± 1.0 µm) and the internal cavity volume (TFE: 2.43 ± 0.50 mm(3) cm(-2), control: 1.77 ± 0.30 mm(3) cm(-2)). No consistent differences were detected between drought-resistant and drought-sensitive taxa, although interactions occurred between drought-sensitivity status and drought treatment for the palisade mesophyll thickness (P = 0.034) and the cavity volume of the leaves (P = 0.025). The limited response to water deficit probably reflects a tight co-ordination between leaf morphology, water relations and photosynthetic properties. This suggests that there is little plasticity in these aspects of plant anatomy in these taxa, and that phenotypic plasticity in leaf traits may not facilitate the acclimation of Amazonian trees to the predicted future reductions in

  13. Body temperature regulation during acclimation to cold and hypoxia in rats.

    Science.gov (United States)

    Cadena, V; Tattersall, G J

    2014-12-01

    Extreme environmental conditions present challenges for thermoregulation in homoeothermic organisms such as mammals. Such challenges are exacerbated when two stressors are experienced simultaneously and each stimulus evokes opposing physiological responses. This is the case of cold, which induces an increase in thermogenesis, and hypoxia, which suppresses metabolism conserving oxygen and preventing hypoxaemia. As an initial approach to understanding the thermoregulatory responses to cold and hypoxia in a small mammal, we explored the effects of acclimation to these two stressors on the body temperature (Tb) and the daily and ultradian Tb variations of Sprague-Dawley rats. As Tb is influenced by sleep-wake cycles, these Tb variations reflect underlying adjustments in set-point and thermosensitivity. The Tb of rats decreased precipitously during initial hypoxic exposure which was more pronounced in cold (Tb=33.4 ± 0.13) than in room temperature (Tb=35.74 ± 0.17) conditions. This decline was followed by an increase in Tb stabilising at a new level ~0.5°C and ~1.4°C below normoxic values at room and cold temperatures, respectively. Daily Tb variations were blunted during hypoxia with a greater effect in the cold. Ultradian Tb variations exhibited daily rhythmicity that disappeared under hypoxia, independent of ambient temperature. The adjustments in Tb during hypoxia and/or cold are in agreement with the hypothesis that an initial decrease in the Tb set-point is followed by its partial re-establishment with chronic hypoxia. This rebound of the Tb set-point might reflect cellular adjustments that would allow animals to better deal with low oxygen conditions, diminishing the drive for a lower Tb set-point. Cold and hypoxia are characteristic of high altitude environments. Understanding how mammals cope with changes in oxygen and temperature will shed light into their ability to colonize new environments along altitudinal clines and increase our understanding of how

  14. Derivation of Mortal Injury Metric for Studies of Rapid Decompression of Depth-Acclimated Physostomous Fish

    Energy Technology Data Exchange (ETDEWEB)

    McKinstry, Craig A.; Carlson, Thomas J.; Brown, Richard S.

    2007-11-05

    In 2005 the U.S. Army Corps of Engineers (USACE) began a study to investigate the response of hatchery and run-of-the-river (ROR) juvenile Chinook salmon to the effects of rapid decompression during passage through mainstem Federal Columbia River Power System (FCRPS) Kaplan turbines. In laboratory studies conducted by Pacific Northwest National Laboratory (PNNL) for USACE since 2005, juvenile fish have been exposed to rapid decompression in a barometric pressure chamber. An initial study considered the response of juvenile Chinook salmon bearing radio transmitters to rapid decompression resulting from exposure to a pressure time history simulating the worst case condition that might be experienced during passage through an operating turbine. The study in 2005 found that acclimation depth was a very important treatment factor that greatly influenced the significantly higher incidence of injury and mortality of rapidly decompressed Chinook salmon bearing radio telemetry devices. In 2006 we initiated a statistical investigation using data in hand into derivation of a new end-point measure for assessment of the physiological response of juvenile Chinook salmon to rapid decompression. Our goal was a measure that would more fully utilize both mortality and injury data while providing a better assessment of the most likely survival outcome for juvenile physostomous fish exposed to rapid decompression. The conclusion of the analysis process was to classify fish as mortally injured when any of the 8 injuries are present, regardless of whether the fish was last observed alive or not. The mortally injured classification has replaced mortality as the end point metric for our rapid decompression studies. The process described in this report is an example of how a data set may be analyzed to identify decision criterion for objective classification of test fish to a specific end-point. The resulting list of 8 mortal injuries is applicable to assess injuries from rapid

  15. Derivation of Mortal Injury Metric for Studies of Rapid Decompression of Depth-Acclimated Physostomous Fish

    Energy Technology Data Exchange (ETDEWEB)

    McKinstry, Craig A.; Carlson, Thomas J.; Brown, Richard S.

    2007-11-05

    In 2005 the U.S. Army Corps of Engineers (USACE) began a study to investigate the response of hatchery and run-of-the-river (ROR) juvenile Chinook salmon to the effects of rapid decompression during passage through mainstem Federal Columbia River Power System (FCRPS) Kaplan turbines. In laboratory studies conducted by Pacific Northwest National Laboratory (PNNL) for USACE since 2005, juvenile fish have been exposed to rapid decompression in a barometric pressure chamber. An initial study considered the response of juvenile Chinook salmon bearing radio transmitters to rapid decompression resulting from exposure to a pressure time history simulating the worst case condition that might be experienced during passage through an operating turbine. The study in 2005 found that acclimation depth was a very important treatment factor that greatly influenced the significantly higher incidence of injury and mortality of rapidly decompressed Chinook salmon bearing radio telemetry devices. In 2006 we initiated a statistical investigation using data in hand into derivation of a new end-point measure for assessment of the physiological response of juvenile Chinook salmon to rapid decompression. Our goal was a measure that would more fully utilize both mortality and injury data while providing a better assessment of the most likely survival outcome for juvenile physostomous fish exposed to rapid decompression. The conclusion of the analysis process was to classify fish as mortally injured when any of the 8 injuries are present, regardless of whether the fish was last observed alive or not. The mortally injured classification has replaced mortality as the end point metric for our rapid decompression studies. The process described in this report is an example of how a data set may be analyzed to identify decision criterion for objective classification of test fish to a specific end-point. The resulting list of 8 mortal injuries is applicable to assess injuries from rapid

  16. Acclimation of croton and hibiscus seedlings in response to the application of indobultiric acid and humic acid for rooting

    Directory of Open Access Journals (Sweden)

    Lílian Estrela Borges Baldotto

    2015-06-01

    Full Text Available The vegetative propagation of ornamental plants can be accelerated by applying plant growth regulators. Amongst them, the use of auxins, plant hormones with physiological effects on cell elongation and rooting have stood out. Alternatively, the application of humic acids, bioactive fraction of soil organic matter, also results in increases in rooting cuttings of ornamental plants. The objective of this work was to study the growth characteristics and the nutritional contents of croton and hibiscus plants during acclimation of seedlings in response to different concentrations of indolebutyric acid (IBA and humic acid (HA applied to cuttings for rooting. The experiment was conducted in greenhouse, and the apical stem cuttings were treated with solutions with concentrations of 0, 250, 500, 1000 and 2000 mg L-1of IBA and 0, 10, 20, 30 and 40 mg L-1 of C from HA. At 45 days of rooting in carbonized rice husk, they were individually transferred to plastic bags of 2.0 dm3 containing a mixture of soil: sand: manure (2: 1: 1 as substrate. At 90 days of acclimation, the plants were collected for measurement of growth and nutritional variables. The results showed that the application of the IBA stimulates the absorption of nutrients and growth of croton cuttings and transplanted hibiscus, contributing to formation of vigorous seedlings. A similar response occurred with the application of HA in hibiscus cuttings

  17. Enhanced drought tolerance of a soil-dwelling springtail by pre-acclimation to a mild drought stress.

    Science.gov (United States)

    Sjursen, H; Bayley, M; Holmstrup, M

    2001-09-01

    The springtail Folsomia candida has a highly permeable cuticle, but is able to survive several weeks at 98.2%RH. This corresponds to a water potential deficit of about 17bars between the environment and the normal osmotic pressure of the body fluids of this animal. Recent studies have shown a water vapour absorption mechanism by accumulation of sugars and polyols (SP) in F. candida, which explains how this species can survive dehydrating conditions. In the present study, adult F. candida were pre-acclimated at 98.2%RH to induce the accumulation of SP, and were subsequently exposed for additional desiccating conditions from 98 to 94%RH. Activity level, water content, osmotic pressure of body fluids and SP composition were investigated. After the desiccation period, the animals were rehydrated at 100%RH and survival was assessed. The results showed that F. candida survived a more severe drought stress when it had been pre-acclimated to 98.2%RH before exposure to lower humidity. This species was able to maintain hyperosmosity to the surroundings at 95.5%RH, suggesting that it can absorb water vapour down to this limit. Below this limit, trehalose levels increased while myo-inositol levels decreased. We propose that this is a change of survival strategy where F. candida at mild desiccation levels seek to retain water by colligative means (remain hyperosmotic), but at severe desiccation levels switches to an anhydrobiotic strategy.

  18. Intracerebroventricular administration of leptin increase physical activity but has no effect on thermogenesis in cold-acclimated rats.

    Science.gov (United States)

    Tang, Gang-Bin; Tang, Xiang-Fang; Li, Kui; Wang, De-Hua

    2015-06-08

    Most small homotherms display low leptin level in response to chronic cold exposure. Cold-induced hypoleptinemia was proved to induce hyperphagia. However, it is still not clear whether hypoleptinemia regulates energy expenditure in cold condition. We try to answer this question in chronic cold-acclimated rats. Results showed that 5-day intracerebroventricular(ICV) infusion of leptin (5 μg/day) had no effects on basal and adaptive thermogenesis and uncoupling protein 1 expression. Physical activity was increased by leptin treatment. We further determined whether ghrelin could reverse the increasing effect of leptin on physical activity. Coadministration of ghrelin (1.2 μg/day) completely reversed the effect of leptin on physical activity. Collectively, this study indicated the regulation of leptin on energy expenditure during cold acclimation may be mainly mediated by physical activity but not by thermogenesis. Our study outlined behavioral role of leptin during the adaptation to cold, which adds some new knowledge to promote our understanding of cold-induced metabolic adaptation.

  19. Proteomics reveals the overlapping roles of hydrogen peroxide and nitric oxide in the acclimation of citrus plants to salinity.

    Science.gov (United States)

    Tanou, Georgia; Job, Claudette; Rajjou, Loïc; Arc, Erwann; Belghazi, Maya; Diamantidis, Grigorios; Molassiotis, Athannasios; Job, Dominique

    2009-12-01

    Hydrogen peroxide (H(2)O(2)) and nitric oxide (*NO) are key reactive species in signal transduction pathways leading to activation of plant defense against biotic or abiotic stress. Here, we investigated the effect of pre-treating citrus plants (Citrus aurantium L.) with either of these two molecules on plant acclimation to salinity and show that both pre-treatments strongly reduced the detrimental phenotypical and physiological effects accompanying this stress. A proteomic analysis disclosed 85 leaf proteins that underwent significant quantitative variations in plants directly exposed to salt stress. A large part of these changes was not observed with salt-stressed plants pre-treated with either H(2)O(2) or sodium nitroprusside (SNP; a *NO-releasing chemical). We also identified several proteins undergoing changes either in their oxidation (carbonylation; 40 proteins) and/or S-nitrosylation (49 proteins) status in response to salinity stress. Both H(2)O(2) and SNP pre-treatments before salinity stress alleviated salinity-induced protein carbonylation and shifted the accumulation levels of leaf S-nitrosylated proteins to those of unstressed control plants. Altogether, the results indicate an overlap between H(2)O(2)- and *NO-signaling pathways in acclimation to salinity and suggest that the oxidation and S-nitrosylation patterns of leaf proteins are specific molecular signatures of citrus plant vigour under stressful conditions.

  20. Soluble Sugars and Sucrose-Metabolizing Enzymes Related to Cold Acclimation of Sweet Cherry Cultivars Grafted on Different Rootstocks

    Directory of Open Access Journals (Sweden)

    Ece Turhan

    2012-01-01

    Full Text Available The bark tissues were collected from 4-year-old sweet cherry trees cvs. 0900 Ziraat and Lambert grafted on Gisela 5 and Mazzard rootstocks in cold-acclimated (CA and nonacclimated (NA stages. Bark tissues subjected to 4°C and −5°C injured to a limited extent in both stages. However, more than 50% injury occurred by temperatures equal to or colder than −15°C only in NA period. Total soluble sugar (TSS, reducing sugars, and sucrose contents were higher in CA than those in NA stages in all samples. The activities of acid invertase (EC 3.2.1.26 and sucrose synthase (SS (EC 2.4.2.13 enzymes were higher in NA stage than those in CA stage. Considering the rootstocks, reducing sugars were higher in both cultivars grafted on Gisela 5 whereas sucrose contents were higher in both cultivars grafted on Mazzard. However, the enzyme activities of both cultivars were higher on Mazzard rootstock than on Gisela 5. In conclusion, cold hardiness of sweet cherry graft combinations was suggested by increasing their TSS, reducing sugars, and sucrose contents significantly in the CA stage. Moreover, acid invertase and SS are down regulated during cold acclimation. Indeed the results suggested that Mazzard is more cold-hardy rootstock than Gisela 5.

  1. Tests of the contribution of acclimation to geographic variation in water loss rates of the West Indian lizard Anolis cristatellus.

    Science.gov (United States)

    Gunderson, Alex R; Siegel, Jeremy; Leal, Manuel

    2011-10-01

    Phenotypic plasticity can contribute to the process of adaptive radiation by facilitating population persistence in novel environments. West Indian Anolis lizards provide a classic example of an adaptive radiation, in which divergence has occurred along two primary ecological axes: structural microhabitat and climate. Adaptive plasticity in limb morphology is hypothesized to have facilitated divergence along the structural niche axis in Anolis, but very little work has explored plasticity in physiological traits. Here, we experimentally ask whether Puerto Rican Anolis cristatellus from mesic and xeric habitats differ in desiccation rates, and whether these lizards exhibit an acclimation response to changes in relative humidity. We first present microclimatic data collected at lizard perch sites that demonstrate that abiotic conditions experienced by lizards differ between mesic and xeric habitat types. In Experiment 1, we measured desiccation rates of lizards from both habitats maintained under identical laboratory conditions. This experiment demonstrated that desiccation rates differ between populations; xeric lizards lose water more slowly than mesic lizards. In Experiment 2, lizards from each habitat were either maintained under the conditions of Experiment 1, or under extremely low relative humidity. Desiccation rates did not differ between lizards from the same habitat maintained under different treatments and xeric lizards maintained lower desiccation rates than mesic lizards within each treatment. Our results demonstrate that A. cristatellus does not exhibit an acclimation response to abrupt changes of hydric conditions, and suggest that tropical Anolis lizards might be unable to exhibit physiological plasticity in desiccation rates in response to varying climatic conditions.

  2. Assessment of Barotrauma Resulting from Rapid Decompression of Depth Acclimated Juvenile Chinook Salmon Bearing Radio Telemetry Transmitters

    Energy Technology Data Exchange (ETDEWEB)

    Brown, Richard S.; Carlson, Thomas J.; Welch, Abigail E.; Stephenson, John R.; Abernethy, Cary S.; McKinstry, Craig A.; Theriault, Marie-Helene

    2007-09-06

    A multifactor study was conducted by Battelle for the US Army Corps of Engineers to assess the significance of the presence of a radio telemetry transmitter on the effects of rapid decompression from simulated hydro turbine passage on depth acclimated juvenile run-of-the-river Chinook salmon. Study factors were: (1) juvenile chinook salmon age;, subyearling or yearling, (2) radio transmitter present or absent, (3) three transmitter implantation factors: gastric, surgical, and no transmitter, and (4) four acclimation depth factors: 1, 10, 20, and 40 foot submergence equivalent absolute pressure, for a total of 48 unique treatments. Exposed fish were examined for changes in behavior, presence or absence of barotrauma injuries, and immediate or delayed mortality. Logistic models were used to test hypotheses that addressed study objectives. The presence of a radio transmitter was found to significantly increase the risk of barotrauma injury and mortality at exposure to rapid decompression. Gastric implantation was found to present a higher risk than surgical implantation. Fish were exposed within 48 hours of transmitter implantation so surgical incisions were not completely healed. The difference in results obtained for gastric and surgical implantation methods may be the result of study design and the results may have been different if tested fish had completely healed surgical wounds. However, the test did simulate the typical surgical-release time frame for in-river telemetry studies of fish survival so the results are probably representative for fish passing through a turbine shortly following release into the river. The finding of a significant difference in response to rapid decompression between fish bearing radio transmitters and those not implies a bias may exist in estimates of turbine passage survival obtained using radio telemetry. However, the rapid decompression (simulated turbine passage) conditions used for the study represented near worst case exposure

  3. Affect Regulation

    DEFF Research Database (Denmark)

    Pedersen, Signe Holm; Poulsen, Stig Bernt; Lunn, Susanne

    2014-01-01

    Gergely and colleagues’ state that their Social Biofeedback Theory of Parental Affect Mirroring” can be seen as a kind of operationalization of the classical psychoanalytic concepts of holding, containing and mirroring. This article examines to what extent the social biofeedback theory of parental...

  4. Photosynthetic parameters and growth in seedlings of Bertholletia excelsa and Carapa guianensis in response to pre-acclimation to full sunlight and mild water stress

    National Research Council Canada - National Science Library

    Azevedo, Gracilene Fernandes da Costa

    2014-01-01

    .... I used six independent pre-acclimation treatments (0, 90 (11h15-12h45), 180 (10h30-13h30), 360 (09h00-15h00), 540 (07h30-16h30) and 720 min (06h00-18h00)) varying the time of exposure to full sunlight...

  5. Defects in a New Class of Sulfate/Anion Transporter Link Sulfur Acclimation Responses to Intracellular Glutathione Levels and Cell Cycle Control1[W][OPEN

    Science.gov (United States)

    Fang, Su-Chiung; Chung, Chin-Lin; Chen, Chun-Han; Lopez-Paz, Cristina; Umen, James G.

    2014-01-01

    We previously identified a mutation, suppressor of mating type locus3 15-1 (smt15-1), that partially suppresses the cell cycle defects caused by loss of the retinoblastoma tumor suppressor-related protein encoded by the MAT3 gene in Chlamydomonas reinhardtii. smt15-1 single mutants were also found to have a cell cycle defect leading to a small-cell phenotype. SMT15 belongs to a previously uncharacterized subfamily of putative membrane-localized sulfate/anion transporters that contain a sulfate transporter domain and are found in a widely distributed subset of eukaryotes and bacteria. Although we observed that smt15-1 has a defect in acclimation to sulfur-limited growth conditions, sulfur acclimation (sac) mutants, which are more severely defective for acclimation to sulfur limitation, do not have cell cycle defects and cannot suppress mat3. Moreover, we found that smt15-1, but not sac mutants, overaccumulates glutathione. In wild-type cells, glutathione fluctuated during the cell cycle, with highest levels in mid G1 phase and lower levels during S and M phases, while in smt15-1, glutathione levels remained elevated during S and M. In addition to increased total glutathione levels, smt15-1 cells had an increased reduced-to-oxidized glutathione redox ratio throughout the cell cycle. These data suggest a role for SMT15 in maintaining glutathione homeostasis that impacts the cell cycle and sulfur acclimation responses. PMID:25361960

  6. Leptin immunoexpression and innervation in rat interscapular brown adipose tissue of cold-acclimated rats: the effects of L-arginine and L-NAME.

    Science.gov (United States)

    Korac, Aleksandra; Buzadzic, Biljana; Petrovic, Vesna; Vasilijevic, Ana; Jankovic, Aleksandra; Korac, Bato

    2008-01-01

    The aim of the present study was to explore the effect of nitric oxide on leptin immunoexpression and innervation in interscapular brown adipose tissue (IBAT) of room- and cold- acclimated rats. Animals acclimated both to room-temperature (22 +/- 1 degrees C) and cold (4 +/- 1 degrees C) were treated with L-arginine, a substrate for nitric oxide synthases (NOSs), or N?-nitro-L-arginine methyl ester (L-NAME), an inhibitor of NOSs, for 45 days. Leptin expression and localization in brown adipocytes was studied by immunohistochemistry, and innervation stained by the Bodian method. Strong leptin immunopositivity was observed in brown adipocytes cytoplasm of all room-acclimated groups, but nuclear leptin positivity was found only in L-NAME treated rats. In cold-acclimated control and L-NAME treated rats leptin immunopositivity was absent, while L-arginine treatment reversed the cold-induced suppression of leptin expression. Comparing to control, L-arginine, and even more L-NAME, at 22 +/- 1 degrees C induced greater innervation. In conclusion, L-arginine treatment changes leptin expression pattern on cold in rat IBAT.

  7. Leptin immunoexpression and innervation in rat interscapular brown adipose tissue of cold-acclimated rats: the effects of L-arginine and L-NAME.

    Directory of Open Access Journals (Sweden)

    Bato Korac

    2008-02-01

    Full Text Available The aim of the present study was to explore the effect of nitric oxide on leptin immunoexpression and innervation in interscapular brown adipose tissue (IBAT of room- and cold- acclimated rats. Animals acclimated both to room-temperature (22 +/- 1 degrees C and cold (4 +/- 1 degrees C were treated with L-arginine, a substrate for nitric oxide synthases (NOSs, or N?-nitro-L-arginine methyl ester (L-NAME, an inhibitor of NOSs, for 45 days. Leptin expression and localization in brown adipocytes was studied by immunohistochemistry, and innervation stained by the Bodian method. Strong leptin immunopositivity was observed in brown adipocytes cytoplasm of all room-acclimated groups, but nuclear leptin positivity was found only in L-NAME treated rats. In cold-acclimated control and L-NAME treated rats leptin immunopositivity was absent, while L-arginine treatment reversed the cold-induced suppression of leptin expression. Comparing to control, L-arginine, and even more L-NAME, at 22 +/- 1 degrees C induced greater innervation. In conclusion, L-arginine treatment changes leptin expression pattern on cold in rat IBAT.

  8. Proton Gradient Regulation5-Like1-Mediated Cyclic Electron Flow Is Crucial for Acclimation to Anoxia and Complementary to Nonphotochemical Quenching in Stress Adaptation

    DEFF Research Database (Denmark)

    Kukuczka, Bernadeta; Magneschi, Leonardo; Petroutsos, Dimitris

    2014-01-01

    double mutant in the green alga Chlamydomonas reinhardtii lacking both PGRL1 and LHCSR3 expression. Phenotypic comparative analyses of this double mutant, together with the single knockout strains and with the P. patens pgrl1, demonstrated that PGRL1 is crucial for acclimation to high light and anoxia...

  9. Grande Ronde Endemic Spring Chinook Salmon Supplementation Project; Lostine River Operations and Maintenance 2004 Smolt Acclimation and Adult Return Report.

    Energy Technology Data Exchange (ETDEWEB)

    Zollman, Richard L.; Eschler, Russell; Sealey, Shawn [Nez Perce Tribe

    2009-03-31

    The Nez Perce Tribe (NPT), through funding provided by the Bonneville Power Administration (BPA), has implemented a Chinook salmon supplementation program (250,000 smolts) on the Lostine River, a tributary to the Grande Ronde River of Oregon. The Grande Ronde Endemic Spring Chinook Salmon Supplementation project, which involves supplementation of the Upper Grande Ronde River and Catherine Creek in addition to the Lostine River, was established to prevent extirpation and increase the number of threatened Snake River spring/summer Chinook salmon (Oncorhynchus tshawytscha) returning to the Grande Ronde River. This report covers the eighth season (1997-2004) of adult Chinook salmon broodstock collection in the Lostine River and the sixth season (1999-2004) of acclimation of resulting Lostine River progeny. Production of Lostine River spring Chinook salmon smolts currently occurs at Lookingglass Fish Hatchery (LGH). The Lostine River supplementation program utilizes two strategies to obtain egg source for production of smolts for supplementation: captive broodstock and conventional broodstock. The captive broodstock strategy involves (1) capture of natural juvenile spring Chinook salmon smolts from the Lostine River, (2) rearing those to adult and spawning them, and (3) rearing the resultant progeny for eventual acclimation and release back into the Lostine River. The conventional broodstock strategy involves (1) capture of natural and hatchery origin adults returning to the Lostine River, (2) holding those adults and spawning them, and (3) rearing the resultant progency for acclimation and release back into the Lostine River. This report focuses on (1) the trapping and collection of adult spring Chinook salmon that return to the Lostine River, which provides the broodstock source for the conventional strategy and (2) the acclimation and release of juvenile spring Chinook salmon produced from the captive broodstock and conventional broodstock strategies. In 2004

  10. Effects of low temperature acclimation on photosynthesis in three Chilean Proteaceae Efectos de la aclimatación a baja temperatura sobre la fotosíntesis de tres proteáceas chilenas

    Directory of Open Access Journals (Sweden)

    MAURICIO CASTRO-ARÉVALO

    2008-09-01

    Full Text Available Embothrium coccineum, Gevuina avellana, and Lomaría ferruginea grow in habitats contrasting in temperature and light intensity. Embothrium coccineum is a pioneer species that establishes itself in open sites completely exposed to variable sunlight and temperature. Gevuina avellana is usually found in more protected sites. Lomaría ferruginea regenerates under the canopy in sites with low thermal oscillations and high humidity. In order to establish an association of their habitats with functional attributes of each species, we studied their photosynthetic responses to temperature and light intensity. We expected that E. coccineum, which grows at full sun, is able to acclimate much better its photosynthetic apparatus to different temperatures than the shade tolerant L. ferruginea and the semi-shade tolerant G. avellana. One group of plants of each species containing six individuals each was subjected to 4 °C (cold-acclimated plants. Another group with the same number of individuals was subjected to 20 °C (non-acclimated plants. In non-acclimated plants of E. coccineum, the photosynthetic rate as measured by 0(2 evolution presented its maximum at 30 °C (16.5 ^mol 0(2 m"² s"¹ with an optimum between 20 and 35 °C, while in G. avellana and L. ferruginea the highest photosynthetic rate (~13 ^mol 0(2 m"² s" was obtained at 25 °C. Cold acclimation significantly reduced the photosynthetic rates of the investigated species. The Q10 for 0(2 evolution decreased significantly in cold-acclimated E. coccineum and G. avellana but not in L. ferruginea. The fluorescence parameters of PSII showed that E. coccineum presents a higher effective quantum yield (cPPSII at both growth temperatures. Photochemical quenching (qP was more affected by the photosynthetic photon flux density (PPFD in L. ferruginea than in the other species. Lomaría ferruginea presented the highest non-photochemical quenching (NPQ at lower PPFD. Thus, the photosynthetic apparatus of

  11. Blood flow and muscle bio-energetics by 31P-nuclear magnetic resonance after local cold acclimation.

    Science.gov (United States)

    Savourey, G; Clerc, L; Vallerand, A L; Leftheriotis, G; Mehier, H; Bittel, J H

    1992-01-01

    To clarify the origin of local cold adaptation and to define precisely its influence on muscle bio-energetics during local exercise, five subjects were subjected to repeated 5 degrees C cold water immersion of the right hand and forearm. The first aim of our investigation was therefore carried out by measuring local skin temperatures and peripheral blood flow during a cold hand test (5 degrees C, 5 min) followed by a 10-min recovery period. The 31P by nuclear magnetic resonance (31PNMR) muscle bio-energetic changes, indicating possible heat production changes, were measured during the recovery period. The second aim of our investigation was carried out by measuring 31PNMR muscle bioenergetics during handgrip exercise (10% of the maximal voluntary contraction for 5 min followed by a 10-min recovery period) performed both at a comfortable ambient temperature (22 degrees C; E) and after a cold hand test (EC), before and after local cold adaptation. Local cold adaptation, confirmed by warmer skin temperatures of the extremities (+30%, P less than 0.05), was related more to an increased peripheral blood flow, as shown by the smaller decrease in systolic peak [-245 (SEM 30) Hz vs -382 (SEM 95) Hz, P less than 0.05] than to a change in local heat production, because muscle bioenergetics did not vary. Acute local cold immersion decreased the inorganic phosphate:phosphocreatine (PC) ratio during EC compared to E [+0.006 (SEM 0.010) vs +0.078 (SEM 0.002) before acclimation and +0.029 (SEM 0.002) vs +0.090 (SEM 0.002) after acclimation respectively, P less than 0.05] without significant change in the PC:beta-adenosine triphosphate ratio and pH. Local adaptation did not modify these results statistically. The recovery of PC during E increased after acclimation [9.0 (SEM 0.2) min vs 3.0 (SEM 0.4) min, P less than 0.05]. These results suggested that local cold adaptation is related more to peripheral blood flow changes than to increased metabolic heat production in the muscle.

  12. Are sun- and shade-type anatomy required for the acclimation of Neoregelia cruenta?

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    FERNANDA REINERT

    2013-06-01

    Full Text Available Sun and shade plants are often discriminated by a number of sun- and shade-type anatomies. Nonetheless, we propose that among tank-bromeliads, changes in rosette architecture satisfy the requirements for coping with contrasting light levels. The tank-bromeliad Neoregelia cruenta naturally colonises sub-habitats ranging from full exposure to direct sunlight, to shaded environments in sand ridge plains. We quantified anatomical and morphological traits of leaves and rosettes of N. cruenta grown under sun and shade conditions. Cells with undulated lateral walls within the water parenchyma are for the first time described for the family. Under high light, leaf blades were wider, shorter, and yellowish. The rosette diameter of sun plants was less than half that of shade plants. Sun leaves overlapped with neighbouring leaves for most of their length, forming a cylindrical rosette where water accumulates. Shade leaves only overlapped in the centre of the rosette. Most anatomical traits were similar under both growth conditions. Stomata were absent from the base of sun leaves, which is probably explained by limited gas exchange at the base of the tight sun-type rosette. Data suggest that the ability of N. cruenta to acclimate to sun and shade is better explained by changes in rosette architecture than by leaf anatomy.Plantas de sol e sombra são frequentemente distinguíveis por diversos aspectos anatômicos. Não obstante, propomos que entre bromélias-tanque, mudanças na arquitetura da roseta satisfazem os requerimentos que permitem habitar extremos de luminosidade. A bromélia-tanque, Neoregelia cruenta naturalmente coloniza microhabitats que variam da exposição direta ao sol, a ambientes sombreados sob o dossel da vegetação de restinga. Quantifi camos aspectos anatômicos e morfológicos das folhas e rosetas de N. cruenta crescida sob sol e sombra. Células com paredes onduladas no parênquima aquífero são pela primeira vez descritas na fam

  13. The effects of thermal acclimation on lethal temperatures and critical thermal limits in the green vegetable bug, Nezara viridula (L. (Hemiptera: Pentatomidae

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    Pol eChanthy

    2012-12-01

    Full Text Available According to geographical distribution, Nezara viridula (Heteroptera: Pentatomidae can be found across tropical, subtropical and temperate regions and this pattern is assumed to reflect differences in thermal adaptation, particularly in cold tolerance. Here the lethal temperature and critical thermal limits (thermal tolerance are examined for N. viridula. The upper lethal temperature for N. viridula at two contrasting climate locations (Breeza and Grafton, New South Wales, Australia was 40.3ºC with 20% survival under the stress of high temperature. The lower lethal temperature did not differ between these two populations and was -8.0ºC with 20% survival under low temperature stress. Survival of N. viridula increased after acclimation at high temperature for seven days. In contrast, when acclimated at lower temperatures (10 and 15ºC, survival of Breeza and Grafton N. viridula was lower than 20% at -8.0ºC.Control-reared N. viridula adults (25ºC had a mean CTMinOnset (cold stupor of 1.3 ± 2.1ºC and a mean CTMax (heat coma of 45.9 ± 0.9ºC. After 7 days of acclimation at 10, 20, 30, or 35ºC, N. viridula adults exhibited a 1ºC change in CTMax and a ~ 1.5ºC change in CTMinOnset. CTMax and CTMinOnset of Breeza and Grafton N. viridula populations did not differ across acclimation temperatures. These results suggest that short-term temperature acclimation is more important than provenance for determining lethal temperatures and critical thermal limits in N. viridula.

  14. The effects of thermal acclimation on lethal temperatures and critical thermal limits in the green vegetable bug, Nezara viridula (L.) (Hemiptera: Pentatomidae).

    Science.gov (United States)

    Chanthy, Pol; Martin, Robert J; Gunning, Robin V; Andrew, Nigel R

    2012-01-01

    According to geographical distribution, Nezara viridula (Heteroptera: Pentatomidae) can be found across tropical, subtropical, and temperate regions and this pattern is assumed to reflect differences in thermal adaptation, particularly in cold tolerance. Here the lethal temperature (LT) and critical thermal limits (CTL) (thermal tolerance) are examined for N. viridula. The upper LT for N. viridula at two contrasting climate locations (Breeza and Grafton, New South Wales, Australia) was 40.3°C with 20% survival under the stress of high temperature. The lower LT did not differ between these two populations and was -8.0°C with 20% survival under low temperature stress. Survival of N. viridula increased after acclimation at high temperature for 7 days. In contrast, when acclimated at lower temperatures (10 and 15°C), survival of Breeza and Grafton N. viridula was lower than 20% at -8.0°C. Control-reared N. viridula adults (25°C) had a mean CT(MinOnset) (cold stupor) of 1.3 ± 2.1°C and a mean CT(Max) (heat coma) of 45.9 ± 0.9°C. After 7 days of acclimation at 10, 20, 30, or 35°C, N. viridula adults exhibited a 1°C change in CT(Max) and a ~1.5°C change in CT(MinOnset). CT(Max) and CT(MinOnset) of Breeza and Grafton N. viridula populations did not differ across acclimation temperatures. These results suggest that short-term temperature acclimation is more important than provenance for determining LTs and CTL in N. viridula.

  15. Effects of exercise-heat acclimation on fluid, electrolyte, and endocrine responses during tilt and +Gz acceleration in women and men.

    Science.gov (United States)

    Greenleaf, J E; Brock, P J; Sciaraffa, D; Polese, A; Elizondo, R

    1985-07-01

    Plasma fluid, electrolyte, protein, renin, and vasoactive hormone (epinephrine, norepinephrine, vasopressin) responses were measured in six women (21-23 yr) and four men (21-38 yr) before and immediately following an orthostatic tolerance test (70 degrees head-up tilt) and a +Gz (head-to-foot) acceleration tolerance test (0.5 G X min-1 linear ramp to grayout). These tests were conducted before and after 12 consecutive days of exercise-heat acclimation when the subjects exercised on a cycle ergometer at a relative oxygen uptake of 44% to 49% peak oxygen uptake in a hot environment (Ta = 40 degrees C, 42% rh). During acclimation plasma volume increased by 10.6% (p less than 0.05) in the women and by 11.9% (p less than 0.05) in the men; in both groups exercise heart rate decreased significantly. After acclimation, acceleration tolerance was unchanged in both groups (range 3.1 to 3.4 G); the women's tilt tolerance was unchanged (range 33.6 to 39.5 min), but the men's tilt tolerance increased from 30.4 min before to 58.3 min (delta = 91%, p less than 0.05) after acclimation. Since the pattern of fluid, electrolyte, and protein shifts and acceleration tolerances in the women and men were virtually the same, the hormone responses were highly variable, and the men's tilt tolerance increased significantly after acclimation, it is clear that responses to tilting cannot be used to predict responses to acceleration. Analysis of data from the present study and the literature suggests that current exercise training regimes should be unrestricted for astronauts who have not previously been highly endurance trained.(ABSTRACT TRUNCATED AT 250 WORDS)

  16. Affective Networks

    Directory of Open Access Journals (Sweden)

    Jodi Dean

    2010-02-01

    Full Text Available This article sets out the idea of affective networks as a constitutive feature of communicative capitalism. It explores the circulation of intensities in contemporary information and communication networks, arguing that this circulation should be theorized in terms of the psychoanalytic notion of the drive. The article includes critical engagements with theorists such as Guy Debord, Jacques Lacan, Tiziana Terranova, and Slavoj Zizek.

  17. Generation and analysis of blueberry transcriptome sequences from leaves, developing fruit, and flower buds from cold acclimation through deacclimation

    Directory of Open Access Journals (Sweden)

    Rowland Lisa J

    2012-04-01

    Full Text Available Abstract Background There has been increased consumption of blueberries in recent years fueled in part because of their many recognized health benefits. Blueberry fruit is very high in anthocyanins, which have been linked to improved night vision, prevention of macular degeneration, anti-cancer activity, and reduced risk of heart disease. Very few genomic resources have been available for blueberry, however. Further development of genomic resources like expressed sequence tags (ESTs, molecular markers, and genetic linkage maps could lead to more rapid genetic improvement. Marker-assisted selection could be used to combine traits for climatic adaptation with fruit and nutritional quality traits. Results Efforts to sequence the transcriptome of the commercial highbush blueberry (Vaccinium corymbosum cultivar Bluecrop and use the sequences to identify genes associated with cold acclimation and fruit development and develop SSR markers for mapping studies are presented here. Transcriptome sequences were generated from blueberry fruit at different stages of development, flower buds at different stages of cold acclimation, and leaves by next-generation Roche 454 sequencing. Over 600,000 reads were assembled into approximately 15,000 contigs and 124,000 singletons. The assembled sequences were annotated and functionally mapped to Gene Ontology (GO terms. Frequency of the most abundant sequences in each of the libraries was compared across all libraries to identify genes that are potentially differentially expressed during cold acclimation and fruit development. Real-time PCR was performed to confirm their differential expression patterns. Overall, 14 out of 17 of the genes examined had differential expression patterns similar to what was predicted from their reads alone. The assembled sequences were also mined for SSRs. From these sequences, 15,886 blueberry EST-SSR loci were identified. Primers were designed from 7,705 of the SSR-containing sequences

  18. Generation and analysis of blueberry transcriptome sequences from leaves, developing fruit, and flower buds from cold acclimation through deacclimation.

    Science.gov (United States)

    Rowland, Lisa J; Alkharouf, Nadim; Darwish, Omar; Ogden, Elizabeth L; Polashock, James J; Bassil, Nahla V; Main, Dorrie

    2012-04-02

    There has been increased consumption of blueberries in recent years fueled in part because of their many recognized health benefits. Blueberry fruit is very high in anthocyanins, which have been linked to improved night vision, prevention of macular degeneration, anti-cancer activity, and reduced risk of heart disease. Very few genomic resources have been available for blueberry, however. Further development of genomic resources like expressed sequence tags (ESTs), molecular markers, and genetic linkage maps could lead to more rapid genetic improvement. Marker-assisted selection could be used to combine traits for climatic adaptation with fruit and nutritional quality traits. Efforts to sequence the transcriptome of the commercial highbush blueberry (Vaccinium corymbosum) cultivar Bluecrop and use the sequences to identify genes associated with cold acclimation and fruit development and develop SSR markers for mapping studies are presented here. Transcriptome sequences were generated from blueberry fruit at different stages of development, flower buds at different stages of cold acclimation, and leaves by next-generation Roche 454 sequencing. Over 600,000 reads were assembled into approximately 15,000 contigs and 124,000 singletons. The assembled sequences were annotated and functionally mapped to Gene Ontology (GO) terms. Frequency of the most abundant sequences in each of the libraries was compared across all libraries to identify genes that are potentially differentially expressed during cold acclimation and fruit development. Real-time PCR was performed to confirm their differential expression patterns. Overall, 14 out of 17 of the genes examined had differential expression patterns similar to what was predicted from their reads alone. The assembled sequences were also mined for SSRs. From these sequences, 15,886 blueberry EST-SSR loci were identified. Primers were designed from 7,705 of the SSR-containing sequences with adequate flanking sequence. One hundred

  19. High TNT-transforming activity by a mixed culture acclimated and maintained on crude-oil-containing media

    Energy Technology Data Exchange (ETDEWEB)

    Popesku, J. T.; Singh, A.; Ward, O. P. [Waterloo Univ., Dept. of Biology, Waterloo, ON (Canada); Xhao, J-S.; Hawari, J. [National Research Council, Biotechnology Research Inst., Montreal, PQ (Canada)

    2003-05-01

    Results of an investigation of the ability of a culture, which neither originated from a munitions-contaminated site, nor was preselected, nor acclimated to TNT-containing media, to rapidly transform TNT, are presented. Cultivation of a mixed culture in glucose-containing medium for 29 hours resulted in almost complete transformation of 100 ppm TNT, suggesting that some of the enzymes and/or metabolic pathways present in crude-oil-degrading micro-organism have the capacity to transform TNT. Both resting and growing cells were able to transform TNT. When sub-cultured, it was found that TNT was able to support growth of the mixed culture when supplied as sole carbon source, sole nitrogen source, or sole carbon and nitrogen source. It is suggested that high TNT-transforming ability without prior subculture on TNT-containing media may have potential applications in bioremediation of munitions-contaminated soil and wastewater. 20 refs., 3 tabs., 2 figs.

  20. Contrasting effects of cold acclimation versus obesogenic diets on chemerin gene expression in brown and brite adipose tissues.

    Science.gov (United States)

    Hansen, Ida R; Jansson, Kim M; Cannon, Barbara; Nedergaard, Jan

    2014-12-01

    Based on results from a signal sequence trap, we investigated chemerin gene expression in brown adipose tissue. Male NMRI mice were exposed to 30, 22 or 4 °C for 3 weeks, or were fed control (chow) diet, cafeteria diet or high-fat diet at thermoneutrality for the same time. In brown adipose tissue, cold acclimation strongly diminished chemerin gene expression, whereas obesogenic diets augmented expression. Qualitatively, changes in expression were paralleled in brite/beige adipose tissues (e.g. inguinal), whereas white adipose tissue (epididymal) and muscle did not react to these cues. Changes in tissue expression were not directly paralleled by alterations in plasma levels. Both these intact animal studies and brown adipocyte cell culture studies indicated that the gene expression regulation was not congruent with a sympathetic/adrenergic control. The data are discussed in relation to suggested endocrine, paracrine and autocrine effects of chemerin.

  1. Acclimatory responses of the Daphnia pulex proteome to environmental changes. II. Chronic exposure to different temperatures (10 and 20°C mainly affects protein metabolism

    Directory of Open Access Journals (Sweden)

    Madlung Johannes

    2009-04-01

    Full Text Available Abstract Background Temperature affects essentially every aspect of the biology of poikilothermic animals including the energy and mass budgets, activity, growth, and reproduction. While thermal effects in ecologically important groups such as daphnids have been intensively studied at the ecosystem level and at least partly at the organismic level, much less is known about the molecular mechanisms underlying the acclimation to different temperatures. By using 2D gel electrophoresis and mass spectrometry, the present study identified the major elements of the temperature-induced subset of the proteome from differently acclimated Daphnia pulex. Results Specific sets of proteins were found to be differentially expressed in 10°C or 20°C acclimated D. pulex. Most cold-repressed proteins comprised secretory enzymes which are involved in protein digestion (trypsins, chymotrypsins, astacin, carboxypeptidases. The cold-induced sets of proteins included several vitellogenin and actin isoforms (cytoplasmic and muscle-specific, and an AAA+ ATPase. Carbohydrate-modifying enzymes were constitutively expressed or down-regulated in the cold. Conclusion Specific sets of cold-repressed and cold-induced proteins in D. pulex can be related to changes in the cellular demand for amino acids or to the compensatory control of physiological processes. The increase of proteolytic enzyme concentration and the decrease of vitellogenin, actin and total protein concentration between 10°C and 20°C acclimated animals reflect the increased amino-acids demand and the reduced protein reserves in the animal's body. Conversely, the increase of actin concentration in cold-acclimated animals may contribute to a compensatory mechanism which ensures the relative constancy of muscular performance. The sheer number of peptidase genes (serine-peptidase-like: > 200, astacin-like: 36, carboxypeptidase-like: 30 in the D. pulex genome suggests large-scaled gene family expansions that

  2. Acclimation of killifish to thermal extremes of hot spring: Transcription of gonadal and liver heat shock genes.

    Science.gov (United States)

    Akbarzadeh, Arash; Leder, Erica H

    2016-01-01

    In this study, we explored the hypothesis that killifish acclimate to thermal extremes through regulation of genes involved in stress and metabolism. We examined the liver and gonadal transcription of heat shock proteins (hsp70, hsp90a, hsp90b), glucokinase (gck), and high mobility group b1 (hmgb1) protein in wild killifish species from hot springs and rivers using quantitative real-time PCR. Moreover, we exposed a river killifish species to a long-term thermal regime of hot spring (37-40°C) and examined the liver transcription of the heat shock genes. Our results showed that hot spring killifish showed a significant, strong upregulation of liver hsp90a. Moreover, the testicular transcript levels of hsp90a, hsp90b, and hsp70 were higher in hot spring killifish than the river ones. The results of the common garden experiments showed that the transcripts of hsp70, hsp90b, and hmgb1 were mildly induced (> twofold) at the time when temperature reached to 37-40°C, while the transcripts of hsp90a were strongly induced (17-fold increase). The level of hsp90a was dramatically more upregulated when fish were maintained in thermal extreme (42-fold change higher than in ambient temperature). Moreover, a significant downregulation of gck transcripts was observed at the time when temperature was raised to 37-40°C (80-fold decrease) and during exposure to long-term thermal extreme (56-fold decrease). It can be concluded that the regulation of heat shock genes particularly hsp90a might be a key factor of the acclimation of fish to high temperature environments like hot springs.

  3. Photosynthetic acclimation of Symbiodinium in hospite depends on vertical position in the tissue of the scleractinian coral Montastrea curta

    Directory of Open Access Journals (Sweden)

    Mads eLichtenberg

    2016-02-01

    Full Text Available Coral photophysiology has been studied intensively from the colony scale down to the scale of single fluorescent pigment granules as light is one of the key determinants for coral health. We studied the photophysiology of the oral and aboral symbiont band of scleractinian coral Montastrea curta to investigate if different acclimation to light exist in hospite on a polyp scale. By combined use of electrochemical and fiber-optic microsensors for O2, scalar irradiance and variable chlorophyll fluorescence, we could characterize the physical and chemical microenvironment experienced by the symbionts and, for the first time, estimate effective quantum yields of PSII photochemistry and rates of electron transport at the position of the zooxanthellae corrected for the in-tissue gradient of scalar irradiance. The oral- and aboral Symbiodinium layers received ~71% and ~33% of surface scalar irradiance, respectively, and the two symbiont layers experience considerable differences in light exposure. Rates of gross photosynthesis did not differ markedly between the oral- and aboral layer and curves of PSII electron transport rates corrected for scalar irradiance in hospite, showed that the light use efficiency under sub-saturating light conditions were similar between the two layers. However, the aboral Symbiodinium band did not experience photosynthetic saturation, even at the highest investigated irradiance where the oral layer was clearly saturated. We thus found a different light acclimation response for the oral and aboral symbiont bands in hospite, and discuss whether such response could be shaped by spectral shifts caused by tissue gradients of scalar irradiance. Based on our experimental finding, combined with previous knowledge, we present a conceptual model on the photophysiology of Symbiodinium residing inside living coral tissue under natural gradients of light and chemical parameters.

  4. Evaluation of o-xylene and other volatile organic compounds removal using a xylene-acclimated biotrickling filter.

    Science.gov (United States)

    Wang, Xiang-Qian; Lu, Bi-Hong; Zhou, Xue-Xia; Li, Wei

    2013-01-01

    In this study, performance evaluation for the gas-phase o-xylene removal using a xylene-acclimated biotrickling filter (BTF) was conducted. Substrate interactions during aerobic biodegradation of three poorly soluble compounds, both individually and in paired mixtures (namely, o-xylene and ethyl acetate, o-xylene and dichloromethane, which are common solvents used by pharmaceutical industry), were also investigated. Experimental results indicate that a maximum elimination capacity of 99.3 g x m(-3) x h(-1) (70% removal) was obtained at an o-xylene loading rate of 143.0 g x m(-3) x h(-1), while the top packing layer (one-third height of the three packing layers) only contributed about 13% to the total elimination capacity. Kinetic constants for o-xylene biodegradation and the pattern of o-xylene removal performance along the height of the BTF were obtained through the modified Michaelis-Menten kinetics and convection-diffusion reaction model, respectively. A reduction of removal efficiency in o-xylene (83.2-74.5% removal at a loading rate of 40.3 g x m(-3) x h(-1) for the total volatile organic compound (VOC) loading rate of 79 g x m(-3) x h(-1)) in the presence of ethyl acetate (100% removal) was observed, while enhanced o-xylene removal efficiency (71.6-78.6% removal at a loading rate of 45.1 g x m(-3) x h(-1) for the total VOC loading rate of 90 g x m(-3) x h(-1)) was achieved in the presence of dichloromethane (35.6% removal). This work shows that a BTF with xylene-acclimated microbial consortia has the ability to remove several poorly soluble compounds, which would advance the knowledge on the treatment of pharmaceutical VOC emissions.

  5. Comparing biomarker responses during thermal acclimation: A lethal vs non-lethal approach in a tropical reef clownfish.

    Science.gov (United States)

    Madeira, Carolina; Madeira, Diana; Diniz, Mário S; Cabral, Henrique N; Vinagre, Catarina

    2017-02-01

    Knowledge of thermal stress biology for most tropical fish species in reef ecosystems under climate change is still quite limited. Thus, the objective of this study was to measure the time-course changes of thermal stress biomarkers in the commercially exploited coral reef fish Amphiprion ocellaris, during a laboratory simulated event of increased temperature. Heat shock protein 70kDa (Hsp70) and total ubiquitin (Ub) were determined in the muscle (lethal method) and in the fin (non-lethal alternative method) under two temperature treatments (control - 26°C and elevated temperature - 30°C) throughout one month with weekly samplings. Results suggest that biomarker basal levels are tissue-specific and influence the degree of response under temperature exposure. Responses were highly inducible in the muscle but not in fin tissue, indicating that the latter is not reliable for monitoring purposes. Thermal stress was observed in the muscle after one week of exposure (both biomarkers increased significantly) and Ub levels then decreased, suggesting the animals were able to acclimate by maintaining high levels of Hsp70 and through an effective protein turnover. In addition, the results show that mortality rates did not differ between treatments. This indicates that A. ocellaris is capable of displaying a plastic response to elevated temperature by adjusting the protein quality control system to protect cell functions, without decreasing survival. Thus, this coral reef fish species presents a significant acclimation potential under ocean warming scenarios of +4°C. Monitoring of thermal stress through a non-lethal method, fin-clipping, although desirable proved to be inadequate for this species. Copyright © 2016 Elsevier Inc. All rights reserved.

  6. Combined active and passive heat exposure induced heat acclimation in a soccer referee before 2014 FIFA World Cup.

    Science.gov (United States)

    Ruddock, A D; Thompson, S W; Hudson, S A; James, C A; Gibson, O R; Mee, J A

    2016-01-01

    The 2014 FIFA World Cup was held in Brazil, where the climatic conditions presented a significant thermoregulatory and perceptual challenge to those unfamiliar with the heat and humidity. This case report documents the adaptation induced by a novel mixed methods (isothermic and passive) heat acclimation (HA) regime for a northern European professional soccer match official prior to the tournament. The intervention involved 13 HA sessions over an 18 day period comprising five isothermic HA sessions whereby intermittent running was used to target and maintain tympanic temperature (Tytemp) at 38 °C for 90 min, and seven passive HA sessions of 48 °C water bathing for 30 min. The athlete performed a heat stress test (HST) (35 min running at four incremental intensities in 30 °C) and a repeated high-intensity running test (as many 30 s self-paced efforts as possible, to a maximum of 20, with 30 s passive recovery) before and after the intervention. The mixed methods HA regime increased plasma volume (+7.1 %), and sweat loss (+0.9 L h(-1)), reduced exercising Tytemp (-0.6 °C), and mean body temperature (-0.5 °C). High-intensity running performance improved after HA (+29 %), as did the perception of thermal comfort during exercise (-0.3 units). This data evidences the effectiveness of a practical, mixed methods HA strategy, remotely implemented around training and competition, at inducing the heat acclimation phenotype in a high-level soccer match official.

  7. Grande Ronde Endemic Spring Chinook Salmon Supplementation Project; Lostine River Operations and Maintenance 2007 Smolt Acclimation and Adult Return Report.

    Energy Technology Data Exchange (ETDEWEB)

    Zollman, Richard L.; Eschler, Russell; Sealey, Shawn [Nez Perce Tribe

    2009-03-31

    The Nez Perce Tribe (NPT), through funding provided by the Bonneville Power Administration (BPA), has implemented a Chinook salmon supplementation program (250,000 smolts) on the Lostine River, a tributary to the Grande Ronde River of Oregon. The Grande Ronde Endemic Spring Chinook Salmon Supplementation project, which involves supplementation of the Upper Grande Ronde River and Catherine Creek in addition to the Lostine River, was established to prevent extirpation and increase the number of threatened Snake River spring/summer Chinook salmon (Oncorhynchus tshawytscha) returning to the Grande Ronde River. This report covers the eleventh season (1997-2007) of adult Chinook salmon broodstock collection in the Lostine River and the ninth season (1999-2007) of acclimation of resulting Lostine River progeny. Production of Lostine River spring Chinook salmon smolts currently occurs at Lookingglass Fish Hatchery (LGH). The Lostine River supplementation program utilizes two strategies to obtain egg source for production of smolts for supplementation: captive broodstock and conventional broodstock. The captive broodstock strategy involves (1) capture of natural juvenile spring Chinook salmon smolts from the Lostine River, (2) rearing those to adult and spawning them, and (3) rearing the resultant progeny for eventual acclimation and release back into the Lostine River. The conventional broodstock strategy involves (1) capture of natural and hatchery origin adults returning to the Lostine River, (2) holding those adults and spawning them, and (3) rearing the resultant progeny for acclimation and release back into the Lostine River. This report focuses on (1) the trapping and collection of adult spring Chinook salmon that return to the Lostine River, which provides the broodstock source for the conventional strategy and (2) the acclimation and release of juvenile spring Chinook salmon produced from the captive broodstock and conventional broodstock strategies In 2007

  8. Grande Ronde Endemic Spring Chinook Salmon Supplementation Project; Lostine River Operations and Maintenance 2006 Smolt Acclimation and Adult Return Report.

    Energy Technology Data Exchange (ETDEWEB)

    Zollman, Richard L.; Eschler, Russell; Sealey, Shawn [Nez Perce Tribe

    2009-03-31

    The Nez Perce Tribe (NPT), through funding provided by the Bonneville Power Administration (BPA), has implemented a Chinook salmon supplementation program (250,000 smolts) on the Lostine River, a tributary to the Grande Ronde River of Oregon. The Grande Ronde Endemic Spring Chinook Salmon Supplementation project, which involves supplementation of the Upper Grande Ronde River and Catherine Creek in addition to the Lostine River, was established to prevent extirpation and increase the number of threatened Snake River spring/summer Chinook salmon (Oncorhynchus tshawytscha) returning to the Grande Ronde River. This report covers the tenth season (1997-2006) of adult Chinook salmon broodstock collection in the Lostine River and the eighth season (1999-2006) of acclimation of resulting Lostine River progeny. Production of Lostine River spring Chinook salmon smolts currently occurs at Lookingglass Fish Hatchery (LGH). The Lostine River supplementation program utilizes two strategies to obtain egg source for production of smolts for supplementation: captive broodstock and conventional broodstock. The captive broodstock strategy involves (1) capture of natural juvenile spring Chinook salmon smolts from the Lostine River, (2) rearing those to adult and spawning them, and (3) rearing the resultant progeny for eventual acclimation and release back into the Lostine River. The conventional broodstock strategy involves (1) capture of natural and hatchery origin adults returning to the Lostine River, (2) holding those adults and spawning them, and (3) rearing the resultant progeny for acclimation and release back into the Lostine River. This report focuses on (1) the trapping and collection of adult spring Chinook salmon that return to the Lostine River, which provides the broodstock source for the conventional strategy and (2) the acclimation and release of juvenile spring Chinook salmon produced from the captive broodstock and conventional broodstock strategies In 2006

  9. [Affective dependency].

    Science.gov (United States)

    Scantamburlo, G; Pitchot, W; Ansseau, M

    2013-01-01

    Affective dependency is characterized by emotional distress (insecure attachment) and dependency to another person with a low self-esteem and reassurance need. The paper proposes a reflection on the definition of emotional dependency and the confusion caused by various denominations. Overprotective and authoritarian parenting, cultural and socio-environmental factors may contribute to the development of dependent personality. Psychological epigenetic factors, such as early socio-emotional trauma could on neuronal circuits in prefronto-limbic regions that are essential for emotional behaviour.We also focus on the interrelations between dependent personality, domestic violence and addictions. The objective for the clinician is to propose a restoration of self-esteem and therapeutic strategies focused on autonomy.

  10. High School Drinker Typologies Predict Alcohol Involvement and Psychosocial Adjustment during Acclimation to College

    Science.gov (United States)

    Hersh, Matthew A.; Hussong, Andrea M.

    2006-01-01

    This study examined differences among distinct types of high school drinkers on their alcohol involvement and psychosocial adjustment during the first semester of college. Participants were 147 college freshmen (66% female; 86% Caucasian) from a large Southeastern public university who reported on high school drinking and college stress, affect,…

  11. Photosynthesis-dependent physiological and genetic crosstalk between cold acclimation and cold-induced resistance to fungal pathogens in triticale (Triticosecale Wittm.).

    Science.gov (United States)

    Szechyńska-Hebda, Magdalena; Wąsek, Iwona; Gołębiowska-Pikania, Gabriela; Dubas, Ewa; Żur, Iwona; Wędzony, Maria

    2015-04-01

    The breeding for resistance against fungal pathogens in winter triticale (Triticosecale Wittm.) continues to be hindered by a complexity of the resistance mechanisms, strong interaction with environmental conditions, and dependence on the plant genotype. We showed, that temperature below 4 °C induced the plant genotype-dependent resistance against the fungal pathogen Microdochium nivale. The mechanism involved, at least, the adjustment of the reactions in the PSII proximity and photoprotection, followed by an improvement of the growth and development. The genotypes capable to develop the cold-induced resistance, showed a higher maximum quantum yield of PSII and a more efficient integration of the primary photochemistry of light reactions with the dark reactions. Moreover, induction of the photoprotective mechanism, involving at least the peroxidases scavenging hydrogen peroxide, was observed for such genotypes. Adjustment of the photosynthesis and stress acclimation has enabled fast plant growth and avoidance of the developmental stages sensitive to fungal infection. The same mechanisms allowed the quick regrow of plants during the post-disease period. In contrast, genotypes that were unable to develop resistance despite cold hardening had less flexible balancing of the photoprotection and photoinhibition processes. Traits related to: photosynthesis-dependent cold-acclimation and cold-induced resistance; biomass accumulation and growth; as well as protection system involving peroxidases; were integrated also at a genetic level. Analysing 95 lines of the mapping population SaKa3006×Modus we determined region on chromosomes 5B and 7R shared within all tested traits. Moreover, similar expression pattern of a set of the genes related to PSII was determined with the metaanalysis of the multiple microarray experiments. Comparable results for peroxidases, involving APXs and GPXs and followed by PRXs, indicated a similar function during cold acclimation and defense

  12. The acclimation of Phaeodactylum tricornutum to blue and red light does not influence the photosynthetic light reaction but strongly disturbs the carbon allocation pattern.

    Directory of Open Access Journals (Sweden)

    Anne Jungandreas

    Full Text Available Diatoms are major contributors to the aquatic primary productivity and show an efficient acclimation ability to changing light intensities. Here, we investigated the acclimation of Phaeodactylum tricornutum to different light quality with respect to growth rate, photosynthesis rate, macromolecular composition and the metabolic profile by shifting the light quality from red light (RL to blue light (BL and vice versa. Our results show that cultures pre-acclimated to BL and RL exhibited similar growth performance, photosynthesis rates and metabolite profiles. However, light shift experiments revealed rapid and severe changes in the metabolite profile within 15 min as the initial reaction of light acclimation. Thus, during the shift from RL to BL, increased concentrations of amino acids and TCA cycle intermediates were observed whereas during the BL to RL shift the levels of amino acids were decreased and intermediates of glycolysis accumulated. Accordingly, on the time scale of hours the RL to BL shift led to a redirection of carbon into the synthesis of proteins, whereas during the BL to RL shift an accumulation of carbohydrates occurred. Thus, a vast metabolic reorganization of the cells was observed as the initial reaction to changes in light quality. The results are discussed with respect to a putative direct regulation of cellular enzymes by light quality and by transcriptional regulation. Interestingly, the short-term changes in the metabolome were accompanied by changes in the degree of reduction of the plastoquinone pool. Surprisingly, the RL to BL shift led to a severe inhibition of growth within the first 48 h which was not observed during the BL to RL shift. Furthermore, during the phase of growth arrest the photosynthetic performance did not change. We propose arguments that the growth arrest could have been caused by the reorganization of intracellular carbon partitioning.

  13. The acclimation of Phaeodactylum tricornutum to blue and red light does not influence the photosynthetic light reaction but strongly disturbs the carbon allocation pattern.

    Science.gov (United States)

    Jungandreas, Anne; Schellenberger Costa, Benjamin; Jakob, Torsten; von Bergen, Martin; Baumann, Sven; Wilhelm, Christian

    2014-01-01

    Diatoms are major contributors to the aquatic primary productivity and show an efficient acclimation ability to changing light intensities. Here, we investigated the acclimation of Phaeodactylum tricornutum to different light quality with respect to growth rate, photosynthesis rate, macromolecular composition and the metabolic profile by shifting the light quality from red light (RL) to blue light (BL) and vice versa. Our results show that cultures pre-acclimated to BL and RL exhibited similar growth performance, photosynthesis rates and metabolite profiles. However, light shift experiments revealed rapid and severe changes in the metabolite profile within 15 min as the initial reaction of light acclimation. Thus, during the shift from RL to BL, increased concentrations of amino acids and TCA cycle intermediates were observed whereas during the BL to RL shift the levels of amino acids were decreased and intermediates of glycolysis accumulated. Accordingly, on the time scale of hours the RL to BL shift led to a redirection of carbon into the synthesis of proteins, whereas during the BL to RL shift an accumulation of carbohydrates occurred. Thus, a vast metabolic reorganization of the cells was observed as the initial reaction to changes in light quality. The results are discussed with respect to a putative direct regulation of cellular enzymes by light quality and by transcriptional regulation. Interestingly, the short-term changes in the metabolome were accompanied by changes in the degree of reduction of the plastoquinone pool. Surprisingly, the RL to BL shift led to a severe inhibition of growth within the first 48 h which was not observed during the BL to RL shift. Furthermore, during the phase of growth arrest the photosynthetic performance did not change. We propose arguments that the growth arrest could have been caused by the reorganization of intracellular carbon partitioning.

  14. Low-O₂ acclimation shifts the hypoxia avoidance behaviour of snapper (Pagrus auratus) with only subtle changes in aerobic and anaerobic function.

    Science.gov (United States)

    Cook, Denham G; Iftikar, Fathima I; Baker, Daniel W; Hickey, Anthony J R; Herbert, Neill A

    2013-02-01

    It was hypothesised that chronic hypoxia acclimation (preconditioning) would alter the behavioural low-O(2) avoidance strategy of fish as a result of both aerobic and anaerobic physiological adaptations. Avoidance and physiological responses of juvenile snapper (Pagrus auratus) were therefore investigated following a 6 week period of moderate hypoxia exposure (10.2-12.1 kPa P(O(2)), 21 ± 1 °C) and compared with those of normoxic controls (P(O(2))=20-21 kPa, 21 ± 1 °C). The critical oxygen pressure (P(crit)) limit of both groups was unchanged at ~7 kPa, as were standard, routine and maximum metabolic rates. However, hypoxia-acclimated fish showed increased tolerances to hypoxia in behavioural choice chambers by avoiding lower P(O(2)) levels (3.3 ± 0.7 vs 5.3 ± 1.1 kPa) without displaying greater perturbations of lactate or glucose. This behavioural change was associated with unexpected physiological adjustments. For example, a decrease in blood O(2) carrying capacity was observed after hypoxia acclimation. Also unexpected was an increase in whole-blood P(50) following acclimation to low O(2), perhaps facilitating Hb-O(2) off-loading to tissues. In addition, cardiac mitochondria measured in situ using permeabilised fibres showed improved O(2) uptake efficiencies. The proportion of the anaerobic enzyme lactate dehydrogenase, at least relative to the aerobic marker enzyme citrate synthase, also increased in heart and skeletal red muscle, indicating enhanced anaerobic potential, or in situ lactate metabolism, in these tissues. Overall, these data suggest that a prioritization of O(2) delivery and O(2) utilisation over O(2) uptake during long-term hypoxia may convey a significant survival benefit to snapper in terms of behavioural low-O(2) tolerance.

  15. High-to-low CO2 acclimation reveals plasticity of the photorespiratory pathway and indicates regulatory links to cellular metabolism of Arabidopsis.

    Directory of Open Access Journals (Sweden)

    Stefan Timm

    Full Text Available BACKGROUND: Photorespiratory carbon metabolism was long considered as an essentially closed and nonregulated pathway with little interaction to other metabolic routes except nitrogen metabolism and respiration. Most mutants of this pathway cannot survive in ambient air and require CO(2-enriched air for normal growth. Several studies indicate that this CO(2 requirement is very different for individual mutants, suggesting a higher plasticity and more interaction of photorespiratory metabolism as generally thought. To understand this better, we examined a variety of high- and low-level parameters at 1% CO(2 and their alteration during acclimation of wild-type plants and selected photorespiratory mutants to ambient air. METHODOLOGY AND PRINCIPAL FINDINGS: The wild type and four photorespiratory mutants of Arabidopsis thaliana (Arabidopsis were grown to a defined stadium at 1% CO(2 and then transferred to normal air (0.038% CO(2. All other conditions remained unchanged. This approach allowed unbiased side-by-side monitoring of acclimation processes on several levels. For all lines, diel (24 h leaf growth, photosynthetic gas exchange, and PSII fluorescence were monitored. Metabolite profiling was performed for the wild type and two mutants. During acclimation, considerable variation between the individual genotypes was detected in many of the examined parameters, which correlated with the position of the impaired reaction in the photorespiratory pathway. CONCLUSIONS: Photorespiratory carbon metabolism does not operate as a fully closed pathway. Acclimation from high to low CO(2 was typically steady and consistent for a number of features over several days, but we also found unexpected short-term events, such as an intermittent very massive rise of glycine levels after transition of one particular mutant to ambient air. We conclude that photorespiration is possibly exposed to redox regulation beyond known substrate-level effects. Additionally, our data

  16. Screening and acclimation of efficient simultaneous nitrification and denitrification bacteria and their application in biotreatment of high ammonia pharmaceutical wastewater

    Directory of Open Access Journals (Sweden)

    Jinling Ma,

    2015-04-01

    Full Text Available Simultaneous nitrification and denitrification (SND bacteria can complete nitrification and denitrification processes under aerobic conditions simultaneously, which has some obvious advantages in comparison with traditional method for nitrogen removal, such as reducing energy consumption and construction cost. Three SND bacteria strains, YX3, YX4 and YX6 were isolated from a polluted river and identified as Pseudomonas spp. by phylogenetic analysis based on 16S rDNA sequencing. After cultivated in liquid heterotrophic ammoniation medium at 30°C by shaking at 150 rpm for 3 d, the NH4 + -N removal rates of strains YX3,YX4 and YX6 were 93.50%, 91.50% and 91.00%, respectively; and the total nitrogen removal rates of YX3, YX4 and YX6 were reached 85.75%, 87.33% and 90.46%, respectively. The NO3 - -N removal rates of strains YX3, YX4 and YX6 were 87.24%, 89.88% and 88.73%, respectively, after cultivated in liquid denitrification medium at 30°C by shaking at 150 rpm for 3 d. These results show that all these strains were capable of simultaneous nitrification and denitrification. When strains YX3, YX4 and YX6 were faced to high ammonia pharmaceutical wastewater, NH4 + -N concentrations decreased from 500±78.47 to 238.14±63.77mg/L, 155.82±79.95 mg/L and 214.62±92.69 mg/L, respectively, after cultured at 150 rpm and 30°C for 3 d. After four months of acclimation, the NH4 + -N remove rates were improved significantly under the same culture conditions and the NH4 + -N concentrations decreased linearly from 500±81.79 to 151.9±88.70mg/L, 94.73±58.66 mg/L and 114.49±56.84 mg/L of strains YX3, YX4 and YX6, respectively. All the strains showed rather steady features in biodenitrification of high ammonia pharmaceutical wastewater after acclimation under laboratory conditions. This suggests that all the three strains have great application potential in high ammonia nitrogen pharmaceutical wastewater treatment.

  17. ESKIMO1 is a key gene involved in water economy as well as cold acclimation and salt tolerance

    Directory of Open Access Journals (Sweden)

    Yu Agnes

    2008-12-01

    Full Text Available Abstract Background Drought is a major social and economic problem resulting in huge yield reduction in the field. Today's challenge is to develop plants with reduced water requirements and stable yields in fluctuating environmental conditions. Arabidopsis thaliana is an excellent model for identifying potential targets for plant breeding. Drought tolerance in the field was successfully conferred to crops by transferring genes from this model species. While involved in a plant genomics programme, which aims to identify new genes responsible for plant response to abiotic stress, we identified ESKIMO1 as a key gene involved in plant water economy as well as cold acclimation and salt tolerance. Results All esk1 mutants were more tolerant to freezing, after acclimation, than their wild type counterpart. esk1 mutants also showed increased tolerance to mild water deficit for all traits measured. The mutant's improved tolerance to reduced water supply may be explained by its lower transpiration rate and better water use efficiency (WUE, which was assessed by carbon isotope discrimination and gas exchange measurements. esk1 alleles were also shown to be more tolerant to salt stress. Transcriptomic analysis of one mutant line and its wild-type background was carried out. Under control watering conditions a number of genes were differentially expressed between the mutant and the wild type whereas under mild drought stress this list of genes was reduced. Among the genes that were differentially expressed between the wild type and mutant, two functional categories related to the response to stress or biotic and abiotic stimulus were over-represented. Under salt stress conditions, all gene functional categories were represented equally in both the mutant and wild type. Based on this transcriptome analysis we hypothesise that in control conditions the esk1 mutant behaves as if it was exposed to drought stress. Conclusion Overall our findings suggest that the

  18. Inverse metabolic engineering based on transient acclimation of yeast improves acid-containing xylose fermentation and tolerance to formic and acetic acids.

    Science.gov (United States)

    Hasunuma, Tomohisa; Sakamoto, Takatoshi; Kondo, Akihiko

    2016-01-01

    Improving the production of ethanol from xylose is an important goal in metabolic engineering of Saccharomyces cerevisiae. Furthermore, S. cerevisiae must produce ethanol in the presence of weak acids (formate and acetate) generated during pre-treatment of lignocellulosic biomass. In this study, weak acid-containing xylose fermentation was significantly improved using cells that were acclimated to the weak acids during pre-cultivation. Transcriptome analyses showed that levels of transcripts for transcriptional/translational machinery-related genes (RTC3 and ANB1) were enhanced by formate and acetate acclimation. Recombinant yeast strains overexpressing RTC3 and ANB1 demonstrated improved ethanol production from xylose in the presence of the weak acids, along with improved tolerance to the acids. Novel metabolic engineering strategy based on the combination of short-term acclimation and system-wide analysis was developed, which can develop stress-tolerant strains in a short period of time, although conventional evolutionary engineering approach has required long periods of time to isolate inhibitor-adapted strains.

  19. Acclimation to UV-B radiation and visible light in Lactuca sativa involves up-regulation of photosynthetic performance and orchestration of metabolome-wide responses.

    Science.gov (United States)

    Wargent, J J; Nelson, B C W; McGhie, T K; Barnes, P W

    2015-05-01

    UV-B radiation is often viewed as a source of stress for higher plants. In particular, photosynthetic function has been described as a common target for UV-B impairment; yet as our understanding of UV-B photomorphogenesis increases, there are opportunities to expand the emerging paradigm of regulatory UV response. Lactuca sativa is an important dietary crop species and is often subjected to rapid sunlight exposure at field transfer. Acclimation to UV-B and visible light conditions in L. sativa was dissected using gas exchange and chlorophyll fluorescence measurements, in addition to non-destructive assessments of UV epidermal shielding (SUV ). After UV-B treatment, seedlings were subjected to wide-range metabolomic analysis using liquid chromatography hybrid quadrupole time-of-flight high-resolution mass spectrometry (LC-QTOF-HRMS). During the acclimation period, net photosynthetic rate increased in UV-treated plants, epidermal UV shielding increased in both subsets of plants transferred to the acclimatory conditions (UV+/UV- plants) and Fv /Fm declined slightly in UV+/UV- plants. Metabolomic analysis revealed that a key group of secondary compounds was up-regulated by higher light conditions, yet several of these compounds were elevated further by UV-B radiation. In conclusion, acclimation to UV-B radiation involves co-protection from the effects of visible light, and responses to UV-B radiation at a photosynthetic level may not be consistently viewed as damaging to plant development. © 2014 John Wiley & Sons Ltd.

  20. Acclimation of leaf cohorts expanded under light and water stresses: an adaptive mechanism of Eucryphia cordifolia to face changes in climatic conditions?

    Science.gov (United States)

    Morales, Loreto V; Coopman, Rafael E; Rojas, Roke; Escandón, Antonio B; Flexas, Jaume; Galmés, Jeroni; García-Plazaola, José I; Gago, Jorge; Cabrera, Hernán M; Corcuera, Luis J

    2014-12-01

    Eucryphia cordifolia Cav. is a long-lived evergreen tree species, commonly found as a canopy emergent tree in the Chilean temperate rain forest. This species displays successive leaf cohorts throughout the entire growing season. Thus, full leaf expansion occurs under different environmental conditions during growing such as air temperature, vapor pressure deficit and the progress of moderate water stress (WS). These climate variations can be reflected as differences in anatomical and physiological characteristics among leaf cohorts. Thus, we investigated the potential adaptive role of different co-existing leaf cohorts in seedlings grown under shade, drought stress or a combination of the two. Photosynthetic and anatomical traits were measured in the first displayed leaf cohort and in a subsequent leaf cohort generated during the mid-season. Although most anatomical and photosynthetic pigments did not vary between cohorts, photosynthetic acclimation did occur in the leaf cohort and was mainly driven by biochemical processes such as leaf nitrogen content, Rubisco carboxylation capacity and maximal Photosystem II electron transport rather than CO2 diffusion conductance. Cohort acclimation could be relevant in the context of climate change, as this temperate rainforest will likely face some degree of summer WS even under low light conditions. We suggest that the acclimation of the photosynthetic capacity among current leaf cohorts represents a well-tuned mechanism helping E. cordifolia seedlings to face a single stress like shade or drought stress, but is insufficient to cope with simultaneous stresses.

  1. Biochemical acclimation, stomatal limitation and precipitation patterns underlie decreases in photosynthetic stimulation of soybean (Glycine max) at elevated [CO₂] and temperatures under fully open air field conditions.

    Science.gov (United States)

    Rosenthal, David M; Ruiz-Vera, Ursula M; Siebers, Matthew H; Gray, Sharon B; Bernacchi, Carl J; Ort, Donald R

    2014-09-01

    The net effect of elevated [CO2] and temperature on photosynthetic acclimation and plant productivity is poorly resolved. We assessed the effects of canopy warming and fully open air [CO2] enrichment on (1) the acclimation of two biochemical parameters that frequently limit photosynthesis (A), the maximum carboxylation capacity of Rubisco (Vc,max) and the maximum potential linear electron flux through photosystem II (Jmax), (2) the associated responses of leaf structural and chemical properties related to A, as well as (3) the stomatal limitation (l) imposed on A, for soybean over two growing seasons in a conventionally managed agricultural field in Illinois, USA. Acclimation to elevated [CO2] was consistent over two growing seasons with respect to Vc,max and Jmax. However, elevated temperature significantly decreased Jmax contributing to lower photosynthetic stimulation by elevated CO2. Large seasonal differences in precipitation altered soil moisture availability modulating the complex effects of elevated temperature and CO2 on biochemical and structural properties related to A. Elevated temperature also reduced the benefit of elevated [CO2] by eliminating decreases in stomatal limitation at elevated [CO2]. These results highlight the critical importance of considering multiple environmental factors (i.e. temperature, moisture, [CO2]) when trying to predict plant productivity in the context of climate change. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

  2. The increase in fat content in the warm-acclimated striped hamsters is associated with the down-regulated metabolic thermogenesis.

    Science.gov (United States)

    Tan, Song; Wen, Jing; Shi, Lu-Lu; Wang, Chun-Ming; Wang, Gui-Ying; Zhao, Zhi-Jun

    2016-11-01

    It has been well known that metabolic thermogenesis plays an important role in the thermoregulation of small mammals under different temperatures, while its role in fat accumulation is far from clear. In the present study, several physiological, hormonal, and biochemical measures indicative of metabolic thermogenesis were measured in the weaning striped hamsters after acclimated to a warm condition (30°C) for 1, 3 and 4months. The warm-acclimated groups significantly decreased energy intake, and simultaneously decreased nonshivering thermogenesis compared to those housed at 21°C. Body fat content increased by 29.9%, 22.1% and 19.6% in the hamsters acclimated to 1, 3 or 4months, respectively relative to their counterparts maintain at 21°C (Ptissue (BAT) were significantly down-regulated under the warm conditions. COX activity of BAT, liver, heart and muscle were significantly negatively correlated with body fat content, and the correlation between UCP1 expression and body fat content tended to be negative. These findings suggest that the decrease in the energy spent on metabolic thermogenesis plays an important role in the fat accumulation. The attenuation of COX and UCP1-based BAT activity may be involved in body fat accumulation in animals under warm conditions. Copyright © 2016 Elsevier Inc. All rights reserved.

  3. Effects of freezing and cold acclimation on the plasma membrane of isolated protoplasts. Progress report, May 16, 1992--January 9, 1993

    Energy Technology Data Exchange (ETDEWEB)

    Steponkus, P.L.

    1993-05-01

    Our goal is to provide a mechanistic understanding of the cellular and molecular aspects of freezing injury and cold acclimation from a perspective of the structural and functional integrity of the plasma membrane -- the primary site of freezing injury in winter cereals. We have utilized protoplasts isolated from leaves of winter rye (Secale cereale L. cv Puma) to study the cryobehavior of the plasma membrane during a freeze/thaw cycle. The focus of our current studies is on lesions in the plasma membrane that result from severe freeze-induced dehydration and result in the alteration of the semipermeable characteristics of the plasma membrane so that the protoplasts are osmotically unresponsive. In protoplasts isolated from non-acclimated rye leaves (NA protoplasts), injury is associated with the formation of aparticulate domains in the plasma membrane, aparticulate lamellae subtending the plasma membrane, and lamellar-to-hexagonal II phase transitions in the plasma membrane and the subtending lamellae. However, lamellar-to-hexagonal II phase transitions are not observed following severe dehydration of protoplasts isolated from cold-acclimated rye leaves (ACC protoplasts). Rather, injury is associated with the ``fracture-jump lesion,`` which, in freeze-fracture electron microscopy studies, is manifested as localized deviations in the fracture face of the plasma membrane. The fracture plane ``jumps`` from the plasma membrane to either subtending aparticulate lamellae or aparticulate regions of various endomembranes (predominantly chloroplast envelopes) that are in close apposition with the plasma membrane.

  4. How does temperature affect forest "fungus breath"? Diurnal non-exponential temperature-respiration relationship, and possible longer-term acclimation in fungal sporocarps

    Science.gov (United States)

    Erik A. Lilleskov

    2017-01-01

    Fungal respiration contributes substantially to ecosystem respiration, yet its field temperature response is poorly characterized. I hypothesized that at diurnal time scales, temperature-respiration relationships would be better described by unimodal than exponential models, and at longer time scales both Q10 and mass-specific respiration at 10 °...

  5. Expression of key ion transporters in the gill and esophageal-gastrointestinal tract of euryhaline Mozambique tilapia Oreochromis mossambicus acclimated to fresh water, seawater and hypersaline water.

    Directory of Open Access Journals (Sweden)

    Zhengjun Li

    Full Text Available The ability of euryhaline Mozambique tilapia to tolerate extreme environmental salinities makes it an exc