Serotonergic modulation of hippocampal pyramidal cells in euthermic, cold-acclimated, and hibernating hamsters

Science.gov (United States)

Horrigan, D. J.; Horwitz, B. A.; Horowitz, J. M.

1997-01-01

Serotonergic fibers project to the hippocampus, a brain area previously shown to have distinctive changes in electroencephalograph (EEG) activity during entrance into and arousal from hibernation. The EEG activity is generated by pyramidal cells in both hibernating and nonhibernating species. Using the brain slice preparation, we characterized serotonergic responses of these CA1 pyramidal cells in euthermic, cold-acclimated, and hibernating Syrian hamsters. Stimulation of Shaffer-collateral/commissural fibers evoked fast synaptic excitation of CA1 pyramidal cells, a response monitored by recording population spikes (the synchronous generation of action potentials). Neuromodulation by serotonin (5-HT) decreased population spike amplitude by 54% in cold-acclimated animals, 80% in hibernating hamsters, and 63% in euthermic animals. The depression was significantly greater in slices from hibernators than from cold-acclimated animals. In slices from euthermic animals, changes in extracellular K+ concentration between 2.5 and 5.0 mM did not significantly alter serotonergic responses. The 5-HT1A agonist 8-hydroxy-2(di-n-propylamino)tetralin mimicked serotonergic inhibition in euthermic hamsters. Results show that 5-HT is a robust neuromodulator not only in euthermic animals but also in cold-acclimated and hibernating hamsters.

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

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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.

Effect of photoperiod prior to cold acclimation on freezing tolerance and carbohydrate metabolism in alfalfa (Medicago sativa L.).

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Bertrand, Annick; Bipfubusa, Marie; Claessens, Annie; Rocher, Solen; Castonguay, Yves

2017-11-01

Cold acclimation proceeds sequentially in response to decreases in photoperiod and temperature. This study aimed at assessing the impact of photoperiod prior to cold acclimation on freezing tolerance and related biochemical and molecular responses in two alfalfa cultivars. The fall dormant cultivar Evolution and semi-dormant cultivar 6010 were grown in growth chambers under different photoperiods (8, 10, 12, 14 or 16h) prior to cold acclimation. Freezing tolerance was evaluated as well as carbohydrate concentrations, levels of transcripts encoding enzymes of carbohydrate metabolism as well as a K-3dehydrin, before and after cold acclimation. The fall dormant cultivar Evolution had a better freezing tolerance than the semi-dormant cultivar 6010. The effect of photoperiod prior to cold acclimation on the level of freezing tolerance differed between the two cultivars: an 8h-photoperiod induced the highest level of freezing tolerance in Evolution and the lowest in 6010. In Evolution, the 8h-induced superior freezing tolerance was associated with higher concentration of raffinose-family oligosaccharides (RFO). The transcript levels of sucrose synthase (SuSy) decreased whereas those of sucrose phosphatase synthase (SPS) and galactinol synthase (GaS) increased in response to cold acclimation in both cultivars. Our results indicate that RFO metabolism could be involved in short photoperiod-induced freezing tolerance in dormant alfalfa cultivars. Crown Copyright © 2017. Published by Elsevier B.V. All rights reserved.

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...... using the ability of field released Drosophila melanogaster to find a resource as a proxy of fitness. Measurements were carried out on two continents across a range of temperatures. Cold acclimation improved the flies' ability to find resources at low temperatures. However, this came at a cost at higher...

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

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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

Effects of prolonged acclimation to cold on the extra--and intracellular acid-base status in the land snail Helix lucorum (L.).

Science.gov (United States)

Staikou, A; Stiakakis, M; Michaelidis, B

2001-01-01

The aim of this study was to examine the effect of prolonged acclimation to cold on the acid-base status of extra- and intracellular fluids in the land snail Helix lucorum. For this purpose, acid-base parameters in the hemolymph and tissues were determined. In addition, the buffer values of hemolymph and tissues were determined in order to examine whether they change in the snails during acclimation to cold. According to the results presented, there is an inverse pH-temperature relationship in the hemolymph within the first day of acclimation, which is consistent with alphastat regulation. The Pco2 decreased, and pH in the hemolymph (pH(e)) increased by 0.32 U within the first day of acclimation to cold, which corresponds to a change of 0.013 U degrees C(-1). After the first day of acclimation, Pco2 increased in the hemolymph, resulting in a significant drop in pH(e) by 90 d of acclimation to cold. Acclimation of snails to low temperatures did not change the buffer value of the hemolymph. Also, intracellular pH (pH(i)) and intracellular buffer values remained stable during acclimation to cold for prolonged periods. The latter results in conjunction with those obtained by the in vitro determination of the passive component of intracellular fluids indicate an active regulation of pH(i) in H. lucorum during acclimation to cold.

Metabolite profiling during cold acclimation of Lolium perenne genotypes distinct in the level of frost tolerance.

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Bocian, Aleksandra; Zwierzykowski, Zbigniew; Rapacz, Marcin; Koczyk, Grzegorz; Ciesiołka, Danuta; Kosmala, Arkadiusz

2015-11-01

Abiotic stresses, including low temperature, can significantly reduce plant yielding. The knowledge on the molecular basis of stress tolerance could help to improve its level in species of relatively high importance to agriculture. Unfortunately, the complex research performed so far mainly on model species and also, to some extent, on cereals does not fully cover the demands of other agricultural plants of temperate climate, including forage grasses. Two Lolium perenne (perennial ryegrass) genotypes with contrasting levels of frost tolerance, the high frost tolerant (HFT) and the low frost tolerant (LFT) genotypes, were selected for comparative metabolomic research. The work focused on the analysis of leaf metabolite accumulation before and after seven separate time points of cold acclimation. Gas chromatography-mass spectrometry (GC/MS) was used to identify amino acids (alanine, proline, glycine, glutamic and aspartic acid, serine, lysine and asparagine), carbohydrates (fructose, glucose, sucrose, raffinose and trehalose) and their derivatives (mannitol, sorbitol and inositol) accumulated in leaves in low temperature. The observed differences in the level of frost tolerance between the analysed genotypes could be partially due to the time point of cold acclimation at which the accumulation level of crucial metabolite started to increase. In the HFT genotype, earlier accumulation was observed for proline and asparagine. The increased amounts of alanine, glutamic and aspartic acids, and asparagine during cold acclimation could be involved in the regulation of photosynthesis intensity in L. perenne. Among the analysed carbohydrates, only raffinose revealed a significant association with the acclimation process in this species.

OeFAD8, OeLIP and OeOSM expression and activity in cold-acclimation of Olea europaea, a perennial dicot without winter-dormancy.

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D'Angeli, Simone; Matteucci, Maya; Fattorini, Laura; Gismondi, Angelo; Ludovici, Matteo; Canini, Antonella; Altamura, Maria Maddalena

2016-05-01

Cold-acclimation genes in woody dicots without winter-dormancy, e.g., olive-tree, need investigation. Positive relationships between OeFAD8, OeOSM , and OeLIP19 and olive-tree cold-acclimation exist, and couple with increased lipid unsaturation and cutinisation. Olive-tree is a woody species with no winter-dormancy and low frost-tolerance. However, cold-tolerant genotypes were empirically selected, highlighting that cold-acclimation might be acquired. Proteins needed for olive-tree cold-acclimation are unknown, even if roles for osmotin (OeOSM) as leaf cryoprotectant, and seed lipid-transfer protein for endosperm cutinisation under cold, were demonstrated. In other species, FAD8, coding a desaturase producing α-linolenic acid, is activated by temperature-lowering, concomitantly with bZIP-LIP19 genes. The research was focussed on finding OeLIP19 gene(s) in olive-tree genome, and analyze it/their expression, and that of OeFAD8 and OeOSM, in drupes and leaves under different cold-conditions/developmental stages/genotypes, in comparison with changes in unsaturated lipids and cell wall cutinisation. Cold-induced cytosolic calcium transients always occurred in leaves/drupes of some genotypes, e.g., Moraiolo, but ceased in others, e.g., Canino, at specific drupe stages/cold-treatments, suggesting cold-acclimation acquisition only in the latter genotypes. Canino and Moraiolo were selected for further analyses. Cold-acclimation in Canino was confirmed by an electrolyte leakage from leaf/drupe membranes highly reduced in comparison with Moraiolo. Strong increases in fruit-epicarp/leaf-epidermis cutinisation characterized cold-acclimated Canino, and positively coupled with OeOSM expression, and immunolocalization of the coded protein. OeFAD8 expression increased with cold-acclimation, as the production of α-linolenic acid, and related compounds. An OeLIP19 gene was isolated. Its levels changed with a trend similar to OeFAD8. All together, results sustain a positive

Prefoldins Negatively Regulate Cold Acclimation in Arabidopsis thaliana by Promoting Nuclear Proteasome-Mediated HY5 Degradation.

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Perea-Resa, Carlos; Rodríguez-Milla, Miguel A; Iniesto, Elisa; Rubio, Vicente; Salinas, Julio

2017-06-05

The process of cold acclimation is an important adaptive response whereby many plants from temperate regions increase their freezing tolerance after being exposed to low non-freezing temperatures. The correct development of this response relies on proper accumulation of a number of transcription factors that regulate expression patterns of cold-responsive genes. Multiple studies have revealed a variety of molecular mechanisms involved in promoting the accumulation of these transcription factors. Interestingly, however, the mechanisms implicated in controlling such accumulation to ensure their adequate levels remain largely unknown. In this work, we demonstrate that prefoldins (PFDs) control the levels of HY5, an Arabidopsis transcription factor with a key role in cold acclimation by activating anthocyanin biosynthesis, in response to low temperature. Our results show that, under cold conditions, PFDs accumulate into the nucleus through a DELLA-dependent mechanism, where they interact with HY5, triggering its ubiquitination and subsequent degradation. The degradation of HY5 would result, in turn, in anthocyanin biosynthesis attenuation, ensuring the accurate development of cold acclimation. These findings uncover an unanticipated nuclear function for PFDs in plant responses to abiotic stresses. Copyright © 2017 The Author. Published by Elsevier Inc. All rights reserved.

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

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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.

Cold acclimation improves chill tolerance in the migratory locust through preservation of ion balance and membrane potential

DEFF Research Database (Denmark)

Andersen, Mads; Folkersen, Rasmus; MacMillan, Heath Andrew

2017-01-01

potential (Vm). Several studies have therefore suggested a link between preservation of Vm and cellular survival after cold stress, but none has measured Vm in this context. We tested this hypothesis by acclimating locusts (Locusta migratoria) to high (31°C) and low temperature (11°C) for 4 days before...... revealed that cellular injury during cold exposure occurs when Vm becomes severely depolarized. Interestingly, we found that cellular sensitivity to hypothermic hyperkalaemia was lower in cold-acclimated locusts that were better able to defend Vm whilst exposed to high extracellular [K+]. Together...

Investigating trehalose synthesis genes after cold acclimation in the Antarctic nematode Panagrolaimus sp. DAW1

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Anna C. Seybold

2017-12-01

Full Text Available Panagrolaimus sp. DAW1 is a freeze-tolerant Antarctic nematode which survives extensive intracellular ice formation. The molecular mechanisms of this extreme adaptation are still poorly understood. We recently showed that desiccation-enhanced RNA interference (RNAi soaking can be used in conjunction with quantitative polymerase chain reaction (qPCR to screen for phenotypes associated with reduced expression of candidate genes in Panagrolaimus sp. DAW1. Here, we present the use of this approach to investigate the role of trehalose synthesis genes in this remarkable organism. Previous studies have shown that acclimating Panagrolaimus sp. DAW1 at 5°C before freezing or desiccation substantially enhances survival. In this study, the expression of tps-2 and other genes associated with trehalose metabolism, as well as lea-1, hsp-70 and gpx-1, in cold-acclimated and non-acclimated nematodes was analyzed using qPCR. Pd-tps-2 and Pd-lea-1 were significantly upregulated after cold acclimation, indicating an inducible expression in the cold adaptation of Panagrolaimus sp. DAW1. The role of trehalose synthesis genes in Panagrolaimus sp. DAW1 was further investigated by RNAi. Compared to the controls, Pd-tps-2a(RNAi-treated and cold-acclimated nematodes showed a significant decrease in mRNA, but no change in trehalose content or freezing survival. The involvement of two other trehalose synthesis genes (tps-2b and gob-1 was also investigated. These findings provide the first functional genomic investigation of trehalose synthesis genes in the non-model organism Panagrolaimus sp. DAW1. The presence of several trehalose synthesis genes with different RNAi sensitivities suggests the existence of multiple backup systems in Panagrolaimus sp. DAW1, underlining the importance of this sugar in preparation for freezing.

Impact of abiotic factors on frost resistance and cold acclimation in Salix species and clones

Energy Technology Data Exchange (ETDEWEB)

Fircks, H. von [Swedish Univ. of Agricultural Sciences, Uppsala (Sweden). Dept. of Short Rotation Forestry

1996-12-31

The effects of mineral nitrogen, photoperiod and day-night temperature on frost resistance and growth cessation in Salix species and clones are discussed. Increased nitrogen supply and imbalances between nitrogen and other elements might cause extensive frost damage in plants of Salix. Vegetation frosts below -3 deg C reduces the level of annual yield. Although Salix clones differ in resistance to freezing stress, the capacity to recover and grow after frosts are equal essential properties which affect the growth and biomass production of shoots after night frosts in June. Early autumn frosts causing freezing damage not only may delay the onset of growth cessation and cold acclimation, but also affect the winter survival of shoots. Increased nitrogen supply prior to cold acclimation postponed growth cessation and cold acclimation. Differences in nutrient status in plants cause also differences in retranslocation of mineral nutrients. Absence of damaging autumn frosts allow plants irrespective of nitrogen status to develop a frost resistance of at least - 80 deg C. 21 refs, 1 fig, 3 tabs

Cold stress and acclimation – what is important for metabolic adjustment?

Czech Academy of Sciences Publication Activity Database

Janská, A.; Maršík, Petr; Zelenková, S.; Ovesná, J.

2010-01-01

Roč. 12, č. 3 (2010), s. 395-405 ISSN 1435-8603 R&D Projects: GA MZe QH81287; GA AV ČR KJB400550705 Institutional research plan: CEZ:AV0Z50380511 Keywords : Cold acclimation * crops * metabolomics Subject RIV: GE - Plant Breeding Impact factor: 2.409, year: 2010

Two key temporally distinguishable molecular and cellular components of white adipose tissue browning during cold acclimation.

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Jankovic, Aleksandra; Golic, Igor; Markelic, Milica; Stancic, Ana; Otasevic, Vesna; Buzadzic, Biljana; Korac, Aleksandra; Korac, Bato

2015-08-01

White to brown adipose tissue conversion and thermogenesis can be ignited by different conditions or agents and its sustainability over the long term is still unclear. Browning of rat retroperitoneal white adipose tissue (rpWAT) during cold acclimation involves two temporally apparent components: (1) a predominant non-selective browning of most adipocytes and an initial sharp but transient induction of uncoupling protein 1, peroxisome proliferator-activated receptor (PPAR) coactivator-1α, PPARγ and PPARα expression, and (2) the subsistence of relatively few thermogenically competent adipocytes after 45 days of cold acclimation. The different behaviours of two rpWAT beige/brown adipocyte subsets control temporal aspects of the browning process, and thus regulation of both components may influence body weight and the potential successfulness of anti-obesity therapies. Conversion of white into brown adipose tissue may have important implications in obesity resistance and treatment. Several browning agents or conditions ignite thermogenesis in white adipose tissue (WAT). To reveal the capacity of WAT to function in a brownish/burning mode over the long term, we investigated the progression of the rat retroperitoneal WAT (rpWAT) browning during 45 days of cold acclimation. During the early stages of cold acclimation, the majority of rpWAT adipocytes underwent multilocularization and thermogenic-profile induction, as demonstrated by the presence of a multitude of uncoupling protein 1 (UCP1)-immunopositive paucilocular adipocytes containing peroxisome proliferator-activated receptor (PPAR) coactivator-1α (PGC-1α) and PR domain-containing 16 (PRDM16) in their nuclei. After 45 days, all adipocytes remained PRDM16 immunopositive, but only a few multilocular adipocytes rich in mitochondria remained UCP1/PGC-1α immunopositive. Molecular evidence showed that thermogenic recruitment of rpWAT occurred following cold exposure, but returned to starting levels after cold

Time course of physiological and psychological responses in humans during a 20-day severe-cold-acclimation programme.

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Marius Brazaitis

Full Text Available The time course of physiological and psychological markers during cold acclimation (CA was explored. The experiment included 17 controlled (i.e., until the rectal temperature reached 35.5°C or 170 min had elapsed; for the CA-17 session, the subjects (n = 14 were immersed in water for the same amount of time as that used in the CA-1 session head-out water immersions at a temperature of 14°C over 20 days. The data obtained in this study suggest that the subjects exhibited a thermoregulatory shift from peripheral-to-central to solely central input thermoregulation, as well as from shivering to non-shivering thermogenesis throughout the CA. In the first six CA sessions, a hypothermic type of acclimation was found; further CA (CA-7 to CA-16 led to a transitional shift to a hypothermic-insulative type of acclimation. Interestingly, when the subjects were immersed in water for the same time as that used in the CA-1 session (CA-17, the CA led to a hypothermic type of acclimation. The presence of a metabolic type of thermogenesis was evident only under thermoneutral conditions. Cold-water immersion decreased the concentration of cold-stress markers, reduced the activity of the innate immune system, suppressed specific immunity to a lesser degree and yielded less discomfort and cold sensation. We found a negative correlation between body mass index and Δ metabolic heat production before and after CA.

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.

Deciphering the Metabolic Changes Associated with Diapause Syndrome and Cold Acclimation in the Two-Spotted Spider Mite Tetranychus urticae

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Khodayari, Samira; Moharramipour, Saeid; Larvor, Vanessa; Hidalgo, Kévin; Renault, David

2013-01-01

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 provide novel

The study of the peptide composition of the supernatants from mealworm Tenebrio molitor larvae and goldfish Carassius auratus during cold acclimation

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А. К. Гулевский

2016-11-01

Full Text Available The molecular-mass distribution of peptides from supernatants, obtained from the tissues of larvae Tenebrio molitor and goldfish Carassius auratus during cold acclimation, has been determined by chromatography. The results showed that peptide spectrum of the supernatants from larvae T. molitor and C. auratus varied during cold acclimation. The supernatants from non-acclimated larvae of T. molitor and deacclimated fish possessed the highest number of peptide fractions. Furthermore, the cold-acclimated larvae of T. molitor had the peptide fractions of the low molecular weight (ca. 5.4×102 ÷22.6×102 Da, and non-acclimated insects had the peptides of the high molecular weight (ca. 46.8×102÷66×102 Da. Next, the organ-specific changes of the peptide composition of the goldfish during winter deacclimation have been revealed. Specifically, the low molecular weight peptides (ca. (14.1 ± 0.3×102 and (6.75 ± 0.25×102 Da, have been detected in the C. auratus muscles, and both the high (ca. (67.83 ± 0.21×102 ( ca. 64.16 ± 0.26×102 Da and low (ca. (34.1 ± 1.0×102 and (14.29 ± 0.15×102 Da molecular weight peptides have been detected in the liver. Quantitative and qualitative changes in the peptide spectra from supernatants of the T. molitor and C. auratus during cold acclimation could be one of the mechanisms of their natural adaptation to low temperatures.

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

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

Generation and analysis of blueberry transcriptome sequences from leaves, developing fruit, and flower buds from cold acclimation through deacclimation

Science.gov (United States)

2012-01-01

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 with adequate flanking

Chlorophyll fluorescence imaging accurately quantifies freezing damage and cold acclimation responses in Arabidopsis leaves

Directory of Open Access Journals (Sweden)

Hincha Dirk K

2008-05-01

Full Text Available Abstract Background Freezing tolerance is an important factor in the geographical distribution of plants and strongly influences crop yield. Many plants increase their freezing tolerance during exposure to low, nonfreezing temperatures in a process termed cold acclimation. There is considerable natural variation in the cold acclimation capacity of Arabidopsis that has been used to study the molecular basis of this trait. Accurate methods for the quantitation of freezing damage in leaves that include spatial information about the distribution of damage and the possibility to screen large populations of plants are necessary, but currently not available. In addition, currently used standard methods such as electrolyte leakage assays are very laborious and therefore not easily applicable for large-scale screening purposes. Results We have performed freezing experiments with the Arabidopsis accessions C24 and Tenela, which differ strongly in their freezing tolerance, both before and after cold acclimation. Freezing tolerance of detached leaves was investigated using the well established electrolyte leakage assay as a reference. Chlorophyll fluorescence imaging was used as an alternative method that provides spatial resolution of freezing damage over the leaf area. With both methods, LT50 values (i.e. temperature where 50% damage occurred could be derived as quantitative measures of leaf freezing tolerance. Both methods revealed the expected differences between acclimated and nonacclimated plants and between the two accessions and LT50 values were tightly correlated. However, electrolyte leakage assays consistently yielded higher LT50 values than chlorophyll fluorescence imaging. This was to a large part due to the incubation of leaves for electrolyte leakage measurements in distilled water, which apparently led to secondary damage, while this pre-incubation was not necessary for the chlorophyll fluorescence measurements. Conclusion Chlorophyll

Molecular cloning and expression analysis of KIN10 and cold-acclimation related genes in wild banana 'Huanxi' (Musa itinerans).

Science.gov (United States)

Liu, Weihua; Cheng, Chunzhen; Lai, Gongti; Lin, Yuling; Lai, Zhongxiong

2015-01-01

Banana cultivars may experience chilling or freezing injury in some of their cultivated regions, where wild banana can still grow very well. The clarification of the cold-resistant mechanism of wild banana is vital for cold-resistant banana breeding. In this study, the central stress integrator gene KIN10 and some cold-acclimation related genes (HOS1 and ICE1s) from the cold-resistant wild banana 'Huanxi' (Musa itinerans) were cloned and their expression patterns under different temperature treatments were analyzed. Thirteen full-length cDNA transcripts including 6 KIN10s, 1 HOS1 and 6 ICE1s were successfully cloned. Quantitative real-time PCR (qRT-PCR) results showed that all these genes had the highest expression levels at the critical temperature of banana (13 °C). Under chilling temperature (4 °C), the expression level of KIN10 reduced significantly but the expression of HOS1 was still higher than that at the optimal temperature (28 °C, control). Both KIN10 and HOS1 showed the lowest expression levels at 0 °C, the expression level of ICE1, however, was higher than control. As sucrose plays role in plant cold-acclimation and in regulation of KIN10 and HOS1 bioactivities, the sucrose contents of wild banana under different temperatures were detected. Results showed that the sucrose content increased as temperature lowered. Our result suggested that KIN10 may participate in cold stress response via regulating sucrose biosynthesis, which is helpful in regulating cold acclimation pathway in wild banana.

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.

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

2017-06-01

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 (60µg T 4 /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. Copyright © 2017 Elsevier Inc. All rights reserved.

ESKIMO1 is a key gene involved in water economy as well as cold acclimation and salt tolerance

DEFF Research Database (Denmark)

Bouchabke-Coussa, O.; Quashie, M.L.; Seoane, Jose Miguel

2008-01-01

'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......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...... 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...

Effects of freezing and cold acclimation on the plasma membrane of isolated protoplasts. [Annual report], May 16, 1993--January 29, 1994

Energy Technology Data Exchange (ETDEWEB)

Steponkus, P.L.

1994-06-01

Our aim 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 established that destabilization of the plasma membrane of winter rye, the most freezing-tolerant winter cereal, can result from several different lesions: expansion induced lysis, lamellar-to-hexagonal II phase transitions, and the fracture-jump lesion. The occurrence and incidence of these various lesions, depends on the freeze/thaw protocol and the stage of cold acclimation. In non-acclimated leaves and protoplasts, expansion-induced lysis is the predominant lesion at temperatures between {minus}2 and {minus}5{degree}C, whereas freeze-induced formation of the H{sub II} phase is the predominant lesion at temperatures below {minus}10{degree}C. We investigated whether the difference in freezing tolerance and the threshold temperatures at which the lesions occur in rye and oat are a consequence of differences in the lipid composition of the plasma membrane. There are substantial differences between rye and oat cell membranes both before and after cold acclimation. The plasma membrane of oat contains greater proportions of acylated sterylglucosides and cerebrosides than that of rye, and there is little change in these two lipid classes during cold acclimation. The lyotropic phase behavior of lipid mixtures that resemble the plasma membrane of rye and oat was studied. The differences in lipid composition of rye and oat are of mechanistic significance because of their influence on the hydration characteristics of the plasma membrane, the propensity for dehydration-induced lipid-lipid demixing, and the intrinsic curvature of the lipid monolayers. These studies suggest that strategies for improving the freezing tolerance of winter cereals should include approaches to modify membrane lipid composition.

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

Science.gov (United States)

Abeynayake, Shamila W.; Etzerodt, Thomas P.; Jonavičienė, Kristina; Byrne, Stephen; Asp, Torben; Boelt, Birte

2015-01-01

Perennial ryegrass (Lolium perenne L.) produces high levels of fructans as a mixture of oligosaccharides and polysaccharides with different degrees of polymerization (DP). The present study describes the analysis of the compositional changes in the full spectrum of fructans, fructan distribution between above ground 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, especially DP = 4, in both the top and the roots of “Veyo” and “Falster” in response to low-temperature stress. The accumulation of DP > 50 fructans was only apparent in the top tissues where the Lp1-FFT expression is higher compared to the roots in both “Veyo” and “Falster.” Our results also show the accumulation and depolymerization of fructans with different DP, together with the induction of genes encoding fructosyltransferases and fructan exohydrolases in both “Veyo” and “Falster” during cold acclimation, supporting the hypothesis that fructan synthesis and depolymerization occurring simultaneously. The ecotype “Falster,” adapted to cold climates, increased total fructan content and produced more DP > 7 fructans in the roots than the variety “Veyo,” adapted to warmer climates. This indicates that high-DP fructan accumulation in roots may be an adaptive trait for plant recovery after abiotic stresses. PMID:26029229

Comparative transcriptomic analysis of the response to cold acclimation in Eucalyptus dunnii.

Directory of Open Access Journals (Sweden)

Yiqing Liu

Full Text Available Eucalyptus dunnii is an important macrophanerophyte with high economic value. However, low temperature stress limits its productivity and distribution. To study the cold response mechanisms of E. dunnii, 5 cDNA libraries were constructed from mRNA extracted from leaves exposed to cold stress for varying lengths of time and were evaluated by RNA-Seq analysis. The assembly of the Illumina datasets was optimized using various assembly programs and parameters. The final optimized assembly generated 205,325 transcripts with an average length of 1,701 bp and N50 of 2,627 bp, representing 349.38 Mb of the E. dunnii transcriptome. Among these transcripts, 134,358 transcripts (65.4% were annotated in the Nr database. According to the differential analysis results, most transcripts were up-regulated as the cold stress prolonging, suggesting that these transcripts may be involved in the response to cold stress. In addition, the cold-relevant GO categories, such as 'response to stress' and 'translational initiation', were the markedly enriched GO terms. The assembly of the E. dunnii gene index and the GO classification performed in this study will serve as useful genomic resources for the genetic improvement of E. dunnii and also provide insights into the molecular mechanisms of cold acclimation in E. dunnii.

Intraspecies differences in cold hardiness, carbohydrate content and β-amylase gene expression of Vaccinium corymbosum during cold acclimation and deacclimation.

Science.gov (United States)

Lee, Jun Hyung; Yu, Duk Jun; Kim, Su Jin; Choi, Doil; Lee, Hee Jae

2012-12-01

Changes in cold hardiness, carbohydrate content and β-amylase gene expression were monitored in the shoots of the highbush blueberry (Vaccinium corymbosum L.) cultivars 'Sharpblue' and 'Jersey' during cold acclimation (CA) and deacclimation (DA). The seasonal patterns were similar in both cultivars, but the levels of cold hardiness determined by electrolyte leakage analysis were significantly different; 'Jersey' was hardier than 'Sharpblue'. Cold hardiness was closely related to total soluble sugar content (r = -0.98** and -0.99** for 'Sharpblue' and 'Jersey', respectively). In 'Jersey', more soluble sugars accumulated during CA. Of the detected soluble sugars, glucose, fructose and raffinose contents were significantly associated with cold hardiness in both cultivars. Sucrose was abundant in both cultivars, and stachyose content changed significantly during CA and DA. However, they were not associated with cold hardiness. A sharp decrease in starch contents in the middle of CA coincided with β-amylase gene (VcBMY) expression, indicating the conversion of starch into soluble sugars. During CA, VcBMY was expressed up to twofold higher in 'Jersey' than in 'Sharpblue'. These results suggest that intraspecies differences in the cold hardiness of highbush blueberries are associated with total soluble sugar content, which is driven partly by differential expression of VcBMY.

Inducing Cold-Sensitivity in the Frigophilic Fly Drosophila montana by RNAi.

Directory of Open Access Journals (Sweden)

Felipe M Vigoder

Full Text Available Cold acclimation is a critical physiological adaptation for coping with seasonal cold. By increasing their cold tolerance individuals can remain active for longer at the onset of winter and can recover more quickly from a cold shock. In insects, despite many physiological studies, little is known about the genetic basis of cold acclimation. Recently, transcriptomic analyses in Drosophila virilis and D. montana revealed candidate genes for cold acclimation by identifying genes upregulated during exposure to cold. Here, we test the role of myo-inositol-1-phosphate synthase (Inos, in cold tolerance in D. montana using an RNAi approach. D. montana has a circumpolar distribution and overwinters as an adult in northern latitudes with extreme cold. We assessed cold tolerance of dsRNA knock-down flies using two metrics: chill-coma recovery time (CCRT and mortality rate after cold acclimation. Injection of dsRNAInos did not alter CCRT, either overall or in interaction with the cold treatment, however it did induced cold-specific mortality, with high levels of mortality observed in injected flies acclimated at 5°C but not at 19°C. Overall, injection with dsRNAInos induced a temperature-sensitive mortality rate of over 60% in this normally cold-tolerant species. qPCR analysis confirmed that dsRNA injection successfully reduced gene expression of Inos. Thus, our results demonstrate the involvement of Inos in increasing cold tolerance in D. montana. The potential mechanisms involved by which Inos increases cold tolerance are also discussed.

Cold-acclimation limits low temperature induced photoinhibition by promoting a higher photochemical quantum yield and a more effective PSII restoration in darkness in the Antarctic rather than the Andean ecotype of Colobanthus quitensis Kunt Bartl (Cariophyllaceae

Directory of Open Access Journals (Sweden)

Bascuñán-Godoy Luisa

2012-07-01

Full Text Available Abstract Background Ecotypes of Colobanthus quitensis Kunt Bartl (Cariophyllaceae from Andes Mountains and Maritime Antarctic grow under contrasting photoinhibitory conditions, reaching differential cold tolerance upon cold acclimation. Photoinhibition depends on the extent of photodamage and recovery capability. We propose that cold acclimation increases resistance to low-temperature-induced photoinhibition, limiting photodamage and promoting recovery under cold. Therefore, the Antarctic ecotype (cold hardiest should be less photoinhibited and have better recovery from low-temperature-induced photoinhibition than the Andean ecotype. Both ecotypes were exposed to cold induced photoinhibitory treatment (PhT. Photoinhibition and recovery of photosystem II (PSII was followed by fluorescence, CO2 exchange, and immunoblotting analyses. Results The same reduction (25% in maximum PSII efficiency (Fv/Fm was observed in both cold-acclimated (CA and non-acclimated (NA plants under PhT. A full recovery was observed in CA plants of both ecotypes under dark conditions, but CA Antarctic plants recover faster than the Andean ecotype. Under PhT, CA plants maintain their quantum yield of PSII, while NA plants reduced it strongly (50% and 73% for Andean and Antarctic plants respectively. Cold acclimation induced the maintenance of PsaA and Cyt b6/f and reduced a 41% the excitation pressure in Antarctic plants, exhibiting the lowest level under PhT. xCold acclimation decreased significantly NPQs in both ecotypes, and reduced chlorophylls and D1 degradation in Andean plants under PhT. NA and CA plants were able to fully restore their normal photosynthesis, while CA Antarctic plants reached 50% higher photosynthetic rates after recovery, which was associated to electron fluxes maintenance under photoinhibitory conditions. Conclusions Cold acclimation has a greater importance on the recovery process than on limiting photodamage. Cold acclimation determined the

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

. 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......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...... 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...

The effect of temperature and thermal acclimation on the sustainable performance of swimming scup.

Science.gov (United States)

Rome, Lawrence C

2007-11-29

There is a significant reduction in overall maximum power output of muscle at low temperatures due to reduced steady-state (i.e. maximum activation) power-generating capabilities of muscle. However, during cyclical locomotion, a further reduction in power is due to the interplay between non-steady-state contractile properties of muscle (i.e. rates of activation and relaxation) and the stimulation and the length-change pattern muscle undergoes in vivo. In particular, even though the relaxation rate of scup red muscle is slowed greatly at cold temperatures (10 degrees C), warm-acclimated scup swim with the same stimulus duty cycles at cold as they do at warm temperature, not affording slow-relaxing muscle any additional time to relax. Hence, at 10 degrees C, red muscle generates extremely low or negative work in most parts of the body, at all but the slowest swimming speeds. Do scup shorten their stimulation duration and increase muscle relaxation rate during cold acclimation? At 10 degrees C, electromyography (EMG) duty cycles were 18% shorter in cold-acclimated scup than in warm-acclimated scup. But contrary to the expectations, the red muscle did not have a faster relaxation rate, rather, cold-acclimated muscle had an approximately 50% faster activation rate. By driving cold- and warm-acclimated muscle through cold- and warm-acclimated conditions, we found a very large increase in red muscle power during swimming at 10 degrees C. As expected, reducing stimulation duration markedly increased power output. However, the increased rate of activation alone produced an even greater effect. Hence, to fully understand thermal acclimation, it is necessary to examine the whole system under realistic physiological conditions.

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.

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

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...... the ability to respond adaptively to temperature acclimation, and (3) tropical species with low basal resistance show stronger adaptive plastic responses to developmental acclimation compared to widespread species...

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.

Acclimation increases freezing stress response of Arabidopsis thaliana at proteome level

KAUST Repository

Fanucchi, Francesca; Alpi, Emanuele; Olivieri, Stefano; Cannistraci, Carlo; Bachi, Angela; Alpi, Amedeo; Alessio, Massimo

2012-01-01

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.

Effects of fasting on maximum thermogenesis in temperature-acclimated rats

Science.gov (United States)

Wang, L. C. H.

1981-09-01

To further investigate the limiting effect of substrates on maximum thermogenesis in acute cold exposure, the present study examined the prevalence of this effect at different thermogenic capabilities consequent to cold- or warm-acclimation. Male Sprague-Dawley rats (n=11) were acclimated to 6, 16 and 26‡C, in succession, their thermogenic capabilities after each acclimation temperature were measured under helium-oxygen (21% oxygen, balance helium) at -10‡C after overnight fasting or feeding. Regardless of feeding conditions, both maximum and total heat production were significantly greater in 6>16>26‡C-acclimated conditions. In the fed state, the total heat production was significantly greater than that in the fasted state at all acclimating temperatures but the maximum thermogenesis was significant greater only in the 6 and 16‡C-acclimated states. The results indicate that the limiting effect of substrates on maximum and total thermogenesis is independent of the magnitude of thermogenic capability, suggesting a substrate-dependent component in restricting the effective expression of existing aerobic metabolic capability even under severe stress.

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

and the composition of membrane GPLs in adult Drosophila melanogaster. Long-term cold survival was significantly improved by low acclimation temperature. After 60h at 0 degrees C, more than 80% of the 15 degrees C-acclimated flies survived while none of the 25 degrees C-acclimated flies survived. Cold shock tolerance...... acclimation temperature and correlated with the changes in GPL composition in membranes of adult D. melanogaster. Udgivelsesdato: 2008-Mar...

Alterations in membrane protein-profile during cold treatment of alfalfa

International Nuclear Information System (INIS)

Mohapatra, S.S.; Poole, R.J.; Dhindsa, R.S.

1988-01-01

Changes in pattern of membrane proteins during cold acclimation of alfalfa have been examined. Cold acclimation for 2 to 3 days increases membrane protein content. Labeling of membrane proteins in vivo with [ 35 S]methionine indicates increases in the rate of incorporation as acclimation progresses. Cold acclimation induces the synthesis of about 10 new polypeptides as shown by SDS-PAGE and fluorography of membrane proteins labeled in vivo

Brassinosteroids increase winter survival of winter rye (Secale cereale L.) by affecting photosynthetic capacity and carbohydrate metabolism during the cold acclimation process

Czech Academy of Sciences Publication Activity Database

Pociecha, E.; Dziurka, M.; Oklešťková, Jana; Janeczko, A.

2016-01-01

Roč. 80, č. 2 (2016), s. 127-135 ISSN 0167-6903 R&D Projects: GA ČR GA14-34792S Institutional support: RVO:61389030 Keywords : Chlorophyll a fluorescence * Cold acclimation * Frost tolerance Subject RIV: CB - Analytical Chemistry, Separation Impact factor: 2.646, year: 2016

Physiological role of glucose-6-phosphate dehydrogenase in cold acclimation of strawberry (Fragaria × ananassa)

Science.gov (United States)

Zhang, Yong; Yu, Dingqun; Luo, Ya; Wang, Xiaorong; Chen, Qing; Sun, Bo; Wang, Yan; Liu, Zejing; Tang, Haoru

2018-04-01

In recent years, there has been an increasing interest in study of new resistance mechanism in fruit trees. All these regard the climate change and subsequent fruit production. Glucose-6-phosphate dehydrogenase (G6PDH) catalyzes the first and rate-limiting step of the oxidative pentose phosphate pathway (OPPP), and the expression of this enzyme is related to different biotic and abiotic stresses. Under accumulation of low temperature stress, the significant increase in G6PDH activity was found to be closely correlated to the levels of antioxidant enzymes, malondialdehyde (MDA) contents, sugar contents as well as changes of superoxide (O2•-). It is suggested that the enhancement of cold resistance of strawberry, which induced by cold acclimation, related to the significant increase in G6PDH activity. On one hand, G6PDH activates NADPH oxidase to generate reactive oxygen species (ROS); on the other hand, it may be involved in the activation of antioxidant enzymes, and accelerates many other important NADPH-dependent enzymatic reactions. Then further result in the elevation of membrane stability and cold resistance of strawberry. Interestingly, even though the plants were placed again under a temperature of 25°C for 1 d, the higher cold resistance, enzyme activities and soluble sugar content acquired.

Cold induced changes of adenosine levels in common eelpout (Zoarces viviparus): a role in modulating cytochrome c oxidase expression.

Science.gov (United States)

Eckerle, L G; Lucassen, M; Hirse, T; Pörtner, H O

2008-04-01

Exposure of ectothermic organisms to variations in temperatures causes a transient mismatch between energy supply and demand, which needs to be compensated for during acclimation. Adenosine accumulation from ATP breakdown indicates such an imbalance and its reversal reflects a restoration of energy status. We monitored adenosine levels in blood serum and liver of common eelpout (Zoarces viviparus) during cold exposure in vivo. Furthermore, we tested its effect on the pattern of thermal acclimation in hepatocytes isolated from cold- (4 degrees C) versus warm- (11 degrees C) exposed fish. Adenosine levels increased during cold exposure in vivo and reached a transient maximum after 24 h in serum, but remained permanently elevated in liver. Whole animal cold acclimation induced a rise of liver citrate synthase activity by 44+/-15%, but left cytochrome c oxidase activity (COX) and RNA expression of the respective genes unchanged. Cold incubation of hepatocytes from warm-acclimated fish failed to cause an increase of mitochondrial enzyme activities despite increased COX4 mRNA levels. Conversely, warm acclimation of hepatocytes from cold-acclimated fish reduced both enzyme activities and COX2 and COX4 mRNA levels by 26-37%. Adenosine treatment of both warm- and cold-acclimated hepatocytes suppressed COX activities but activated COX mRNA expression. These effects were not receptor mediated. The present findings indicate that adenosine has the potential to regulate mitochondrial functioning in vivo, albeit the pathways resulting in the contrasting effects on expression and activity need to be identified.

Is BMR repeatable in deer mice? Organ mass correlates and the effects of cold acclimation and natal altitude.

Science.gov (United States)

Russell, G A; Chappell, M A

2007-01-01

Basal metabolic rate (BMR) is probably the most studied aspect of energy metabolism in vertebrate endotherms. Numerous papers have explored its mass allometry, phylogenetic and ecological relationships, and ontogeny. Implicit in many of these studies (and explicit in some) is the view that BMR responds to selection, which requires repeatability and heritability. However, BMR is highly plastic in response to numerous behavioral and environmental factors and there are surprisingly few data on its repeatability. Moreover, the mechanistic underpinnings of variation in BMR are unclear, despite considerable research. We studied BMR repeatability in deer mice (Peromyscus maniculatus) across intervals of 30-60 days, and also examined the influence of birth altitude (3,800 m versus 340 m) and temperature acclimation (to approximately 5 or approximately 20 degrees C) on BMR, and the relationship between BMR and organ size. Neither acclimation temperature nor natal altitude alone influenced BMR, but the combination of birth at high altitude and cold acclimation significantly increased BMR. Few visceral organ masses were correlated to BMR and most were inconsistent across natal altitudes and acclimation temperatures, indicating that no single organ 'controls' variation in BMR. In several treatment groups, the mass of the 'running motor' (combined musculoskeletal mass) was negatively correlated to BMR and the summed mass of visceral organs was positively correlated to BMR. We found no repeatability of BMR in any treatment group. That finding-in sharp contrast to high repeatability of BMR in several other small endotherms-suggests little potential for direct selection to drive BMR evolution in deer mice.

Overexpression of a Panax ginseng tonoplast aquaporin alters salt tolerance, drought tolerance and cold acclimation ability in transgenic Arabidopsis plants.

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Peng, Yanhui; Lin, Wuling; Cai, Weiming; Arora, Rajeev

2007-08-01

Water movement across cellular membranes is regulated largely by a family of water channel proteins called aquaporins (AQPs). Since several abiotic stresses such as, drought, salinity and freezing, manifest themselves via altering water status of plant cells and are linked by the fact that they all result in cellular dehydration, we overexpressed an AQP (tonoplast intrinsic protein) from Panax ginseng, PgTIP1, in transgenic Arabidopsis thaliana plants to test its role in plant's response to drought, salinity and cold acclimation (induced freezing tolerance). Under favorable conditions, PgTIP1 overexpression significantly increased plant growth as determined by the biomass production, and leaf and root morphology. PgTIP1 overexpression had beneficial effect on salt-stress tolerance as indicated by superior growth status and seed germination of transgenic plants under salt stress; shoots of salt-stressed transgenic plants also accumulated greater amounts of Na(+) compared to wild-type plants. Whereas PgTIP1 overexpression diminished the water-deficit tolerance of plants grown in shallow (10 cm deep) pots, the transgenic plants were significantly more tolerant to water stress when grown in 45 cm deep pots. The rationale for this contrasting response, apparently, comes from the differences in the root morphology and leaf water channel activity (speed of dehydration/rehydration) between the transgenic and wild-type plants. Plants overexpressed with PgTIP1 exhibited lower (relative to wild-type control) cold acclimation ability; however, this response was independent of cold-regulated gene expression. Our results demonstrate a significant function of PgTIP1 in growth and development of plant cells, and suggest that the water movement across tonoplast (via AQP) represents a rate-limiting factor for plant vigor under favorable growth conditions and also significantly affect responses of plant to drought, salt and cold stresses.

Insights from the cold transcriptome and metabolome of Dendrobium officinale: global reprogramming of metabolic and gene regulation networks during cold acclimation

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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.

Transcriptome response mediated by cold stress in Lotus japonicus

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Pablo Ignacio Calzadilla

2016-03-01

Full Text Available Members of the Lotus genus are important as agricultural forage sources under marginal environmental conditions given their high nutritional value and tolerance of various abiotic stresses. However, their dry matter production is drastically reduced in cooler seasons, while their response to such conditions is not well studied. This paper analyzes cold acclimation of the genus by studying Lotus japonicus over a stress period of 24 h. High-throughput RNA sequencing was used to identify and classify 1077 differentially expressed genes, of which 713 were up-regulated and 364 were down-regulated. Up-regulated genes were principally related to lipid, cell wall, phenylpropanoid, sugar, and proline regulation, while down-regulated genes affected the photosynthetic process and chloroplast development. Together, a total of 41 cold-inducible transcription factors were identified, including members of the AP2/ERF, NAC, MYB, and WRKY families; two of them were described as putative novel transcription factors. Finally, DREB1/CBFs were described with respect to their cold stress expression profiles. This is the first transcriptome profiling of the model legume L. japonicus under cold stress. Data obtained may be useful in identifying candidate genes for breeding modified species of forage legumes that more readily acclimate to low temperatures

Osmotic versus adrenergic control of ion transport by ionocytes of Fundulus heteroclitus in the cold.

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Tait, Janet C; Mercer, Evan W; Gerber, Lucie; Robertson, George N; Marshall, William S

2017-01-01

In eurythermic vertebrates, acclimation to the cold may produce changes in physiological control systems. We hypothesize that relatively direct osmosensitive control will operate better than adrenergic receptor mediated control of ion transport in cold vs. warm conditions. Fish were acclimated to full strength seawater (SW) at 21°C and 5°C for four weeks, gill samples and blood were taken and opercular epithelia mounted in Ussing style chambers. Short-circuit current (I sc ) at 21°C and 5°C (measured at acclimation temperature), was significantly inhibited by the α 2 -adrenergic agonist clonidine but the ED 50 dose was significantly higher in cold conditions (93.8±16.4nM) than in warm epithelia (47.8±8.1nM) and the maximum inhibition was significantly lower in cold (-66.1±2.2%) vs. warm conditions (-85.6±1.3%), indicating lower sensitivity in the cold. β-Adrenergic responses were unchanged. Hypotonic inhibition of I sc , was higher in warm acclimated (-95%), compared to cold acclimated fish (-75%), while hypertonic stimulations were the same, indicating equal responsiveness to hyperosmotic stimuli. Plasma osmolality was significantly elevated in cold acclimated fish and, by TEM, gill ionocytes from cold acclimated fish had significantly shorter mitochondria. These data are consistent with a shift in these eurythermic animals from complex adrenergic control to relatively simple biomechanical osmotic control of ion secretion in the cold. Copyright © 2016. Published by Elsevier Inc.

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.

Acclimation temperature affects the metabolic response of amphibian skeletal muscle to insulin.

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Petersen, Ann M; Gleeson, Todd T

2011-09-01

Frog skeletal muscle mainly utilizes the substrates glucose and lactate for energy metabolism. The goal of this study was to determine the effect of insulin on the uptake and metabolic fate of lactate and glucose at rest in skeletal muscle of the American bullfrog, Lithobates catesbeiana, under varying temperature regimens. We hypothesize that lactate and glucose metabolic pathways will respond differently to the presence of insulin in cold versus warm acclimated frog tissues, suggesting an interaction between temperature and metabolism under varying environmental conditions. We employed radiolabeled tracer techniques to measure in vitro uptake, oxidation, and incorporation of glucose and lactate into glycogen by isolated muscles from bullfrogs acclimated to 5 °C (cold) or 25 °C (warm). Isolated bundles from Sartorius muscles were incubated at 5 °C, 15 °C, or 25 °C, and in the presence and absence of 0.05 IU/mL bovine insulin. Insulin treatment in the warm acclimated and incubated frogs resulted in an increase in glucose incorporation into glycogen, and an increase in intracellular [glucose] of 0.5 μmol/g (Pmuscle. When compared to the warm treatment group, cold acclimation and incubation resulted in increased rates of glucose oxidation and glycogen synthesis, and a reduction in free intracellular glucose levels (Pmuscles from either acclimation group were incubated at an intermediate temperature of 15 °C, insulin's effect on substrate metabolism was attenuated or even reversed. Therefore, a significant interaction between insulin and acclimation condition in controlling skeletal muscle metabolism appears to exist. Our findings further suggest that one of insulin's actions in frog muscle is to increase glucose incorporation into glycogen, and to reduce reliance on lactate as the primary metabolic fuel. Copyright © 2011 Elsevier Inc. All rights reserved.

Plant plasma membrane proteomics for improving cold tolerance

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Daisuke eTakahashi

2013-04-01

Full Text Available Plants are always exposed to various stresses. We have focused on freezing stress, which causes serious problems for agricultural management. When plants suffer freeze-induced damage, the plasma membrane is thought to be the primary site of injury because of its central role in regulation of various cellular processes. Cold tolerant species, however, adapt to such freezing conditions by modifying cellular components and functions (cold acclimation. One of the most important adaptation mechanisms to freezing is alteration of plasma membrane compositions and functions. Advanced proteomic technologies have succeeded in identification of many candidates that may play roles in adaptation of the plasma membrane to freezing stress. Proteomics results suggest that adaptations of plasma membrane functions to low temperature are associated with alterations of protein compositions during cold acclimation. Some of proteins identified by proteomic approaches have been verified their functional roles in freezing tolerance mechanisms further. Thus, accumulation of proteomic results in the plasma membrane is of importance for application to molecular breeding efforts to increase cold tolerance in crops.

Human whole body cold adaptation.

NARCIS (Netherlands)

Daanen, Hein A.M.; Van Marken Lichtenbelt, Wouter D.

2016-01-01

Reviews on whole body human cold adaptation generally do not distinguish between population studies and dedicated acclimation studies, leading to confusing results. Population studies show that indigenous black Africans have reduced shivering thermogenesis in the cold and poor cold induced

Relationships of self-identified cold tolerance and cold-induced vasodilatation in the finger

Science.gov (United States)

Park, Joonhee; Lee, Joo-Young

2016-04-01

This study was conducted to investigate relationships of self-identified cold tolerance and cold-induced vasodilatation (CIVD) in the finger. Nine males and 34 females participated in the following 2 tests: a CIVD test and a self-reported survey. The CIVD test was conducted 30-min cold-water immersion (3.8 ± 0.3 °C) of the middle finger at an air temperature of 27.9 ± 0.1 °C. The self-reported questionnaire consisted of 28 questions about whole and local body cold and heat tolerances. By a cluster analysis on the survey results, the participants were divided into two groups: high self-identified cold tolerance (HSCT, n = 25) and low self-identified cold tolerance (LSCT, n = 18). LSCT had lower self-identified cold tolerance ( P cold or heat tolerance had relationships with cold tolerance index, T max, and amplitude ( P cold tolerance classified through a standardized survey could be a good index to predict physiological cold tolerance.

Effects of thyroid status on cold-adaptive thermogenesis in Brandt's vole, Microtus brandti.

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Liu, X T; LI, Q F; Huang, C X; Sun, R Y

1997-01-01

Hyper- and hypothyroidism were induced by subcutaneous injection of thyroxine and by oral administration of methimazol in Brandt's voles. The effects of the two treatments on metabolic thermogenesis at 25 degrees C and 4 degrees C were investigated. The level of resting metabolic rate was closely related to thyroid status: high in the hyperthyroid case and low in the hypothyroid case. However, no increase in resting metabolic rate occurred in either case during further cold acclimation. Hyperthyroidism resulted in an increased nonshivering thermogenesis, which was much enhanced by lower temperature, but hypothyroidism led to a suppressed nonshivering thermogenesis in the cold. The state-4 and state-3 respirations and the activities of cytochrome-c oxidase of liver mitochondria were elevated in hyperthyroid animals but attenuated in hypothyroid ones. However, these levels were scarcely changed after further cold acclimation. Both hyperthyroidism and cold acclimation induced the recruitment of brown adipose tissue, but brown adipose tissue was different biochemically in the two cases: in hyperthyroidism, the total protein was reduced, while fat content increased; in cold acclimation, the total and mitochondrial proteins were increased. However, in hypothyroid voles, the normal adaptive changes in brown adipose tissue were impaired in further cold acclimation. The activity of cytochromec oxidase in brown adipose tissue was increased by hyperthyroidism and enhanced in further cold. In contrast, its activity was inhibited in hypothyroid animals, though activated to some extent in cold. These results demonstrate that normal thyroid function is essential for the cold-induced increase of resting metabolic rate and nonshivering thermogenesis and that there is a synergism between thyroid hormone and cold acclimation in the regulation of nonshivering thermogenesis in Brandt's vole. In addition, the blunted response of brown adipocytes to the cold may be the cytological

ESKIMO1 is a key gene involved in water economy as well as cold acclimation and salt tolerance

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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

Direct effects of cold shock: bioassays with three Columbia River organisms

International Nuclear Information System (INIS)

Becker, C.D.; Schneider, M.J.

1975-01-01

Results of studies of the direct effects of cold shock on the pumpkinseed sunfish (representing a warmwater fish), the rainbow trout (representing a coldwater fish), and the common crayfish showed that resistance to cold shock varies between species, is dependent on acclimation temperature, and resistance to temperature declines is dependent on the decline rate. Severe cold shock at a sublethal level is accompanied by disorientation, loss of equilibrium, and immobilization. Pumpkinseed, the warm water species, are most susceptible. Rainbow, the cold water species, are less susceptible; at an acclimation 10 0 C, rainbow survive abrupt shock to levels slightly above freezing. Crayfish, the decapod crustacean, are most resistant; at an acclimation of 15 0 C, crayfish survive abrupt shock to the point just above freezing

The effect of cold priming on the fitness of Arabidopsis thaliana accessions under natural and controlled conditions

DEFF Research Database (Denmark)

Cvetkovic, Jelena; Müller, Klaus; Baier, Margarete

2017-01-01

Priming improves an organism's performance upon a future stress. To test whether cold priming supports protection in spring and how it is affected by cold acclimation, we compared seven Arabidopsis accessions with different cold acclimation potentials in the field and in the greenhouse for growth......, photosynthetic performance and reproductive fitness in March and May after a 14 day long cold-pretreatment at 4 °C. In the plants transferred to the field in May, the effect of the cold pretreatment on the seed yield correlated with the cold acclimation potential of the accessions. In the March transferred...

Effect of thermal acclimation on locomotor energetics and locomotor performance in a lungless salamander, Desmognathus ochrophaeus.

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Feder, M E

1986-03-01

To determine the effects of thermal acclimation upon locomotor performance and the rate of oxygen consumption (MO2) during activity, small (less than 3 g), lungless salamanders, Desmognathus ochrophaeus Cope, were acclimated to three temperatures (5, 13 and 21 degrees C) and exercised at various controlled speeds within an exercise wheel while their MO2 was measured. MO2 increased with speed at low speeds (less than 14 cm min-1). Although animals could sustain greater speeds, MO2 did not increase further. These small, exclusively skin-breathing salamanders could increase their MO2 9-11 times during exercise and could sustain nearly half of the oxygen flux expected across a similar surface area of the mammalian lung. However, their maximum aerobic speed was remarkably slow (14 cm min-1) and their net cost of transport remarkably large (15-17 ml O2 g-1 km-1). Thermal acclimation affected MO2 during activity, the maximum sustainable speed and locomotor stamina in different ways. During exercise at 13 degrees C, cold-acclimated animals had a significantly greater MO2 than warm-acclimated animals, but did not differ in stamina or the maximum sustainable speed. During exercise at 21 degrees C, cold acclimation did not affect the MO2 significantly, but it decreased the stamina and increased the rate of lactate accumulation. Thus, these results suggest that thermal acclimation of the MO2 is not tightly coupled to thermal acclimation of locomotor performance in salamanders.

Frequent extreme cold exposure and brown fat and cold-induced thermogenesis: A study in a monozygotic twin

NARCIS (Netherlands)

M.J. Vosselman (Maarten J.); G.H.E.J. Vijgen (Guy H. E. J.); B.R.M. Kingma (Boris R. M.); B. Brans (Boudewijn); W.D. Van Marken Lichtenbelt (Wouter D.)

2014-01-01

textabstractIntroduction: Mild cold acclimation is known to increase brown adipose tissue (BAT) activity and cold-induced thermogenesis (CIT) in humans. We here tested the effect of a lifestyle with frequent exposure to extreme cold on BAT and CIT in a Dutch man known as 'the Iceman', who has

Human whole body cold adaptation.

OpenAIRE

Daanen, Hein A.M.; Van Marken Lichtenbelt, Wouter D.

2016-01-01

ABSTRACT Reviews on whole body human cold adaptation generally do not distinguish between population studies and dedicated acclimation studies, leading to confusing results. Population studies show that indigenous black Africans have reduced shivering thermogenesis in the cold and poor cold induced vasodilation in fingers and toes compared to Caucasians and Inuit. About 40,000?y after humans left Africa, natives in cold terrestrial areas seems to have developed not only behavioral adaptations...

Bibliography on Cold Regions Science and Technology. Volume 51, Part 2.

Science.gov (United States)

1997-12-01

1997, eng] 51-2291 PäIsson,O.P. Statistical methods in district heating in Iceland [1997, eng] 51-4259 Palta ,J.P. Molecular mechanisms of...Molecular mechanisms of herbaceous plant cold acclimation. Palta , J.P., et al, [I993,eng) 51-664 Mutations affecting freezing tolerance of plant tissues...51-2692 Molecular mechanisms of herbaceous plant cold acclimation. Palta , J.P, et al, [1993,eng] 51-664 Nitrification and denitrification enzyme

Cold temperatures increase cold hardiness in the next generation Ophraella communa beetles.

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Zhong-Shi Zhou

Full Text Available The leaf beetle, Ophraella communa, has been introduced to control the spread of the common ragweed, Ambrosia artemisiifolia, in China. We hypothesized that the beetle, to be able to track host-range expansion into colder climates, can phenotypically adapt to cold temperatures across generations. Therefore, we questioned whether parental experience of colder temperatures increases cold tolerance of the progeny. Specifically, we studied the demography, including development, fecundity, and survival, as well as physiological traits, including supercooling point (SCP, water content, and glycerol content of O. communa progeny whose parents were maintained at different temperature regimes. Overall, the entire immature stage decreased survival of about 0.2%-4.2% when parents experienced cold temperatures compared to control individuals obtained from parents raised at room temperature. However, intrinsic capacity for increase (r, net reproductive rate (R 0 and finite rate of increase (λ of progeny O. communa were maximum when parents experienced cold temperatures. Glycerol contents of both female and male in progeny was significantly higher when maternal and paternal adults were cold acclimated as compared to other treatments. This resulted in the supercooling point of the progeny adults being significantly lower compared to beetles emerging from parents that experienced room temperatures. These results suggest that cold hardiness of O. communa can be promoted by cold acclimation in previous generation, and it might counter-balance reduced survival in the next generation, especially when insects are tracking their host-plants into colder climates.

Reproductive arrest and stress resistance in winter-acclimated Drosophila suzukii.

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Toxopeus, Jantina; Jakobs, Ruth; Ferguson, Laura V; Gariepy, Tara D; Sinclair, Brent J

2016-06-01

Overwintering insects must survive the multiple-stress environment of winter, which includes low temperatures, reduced food and water availability, and cold-active pathogens. Many insects overwinter in diapause, a developmental arrest associated with high stress tolerance. Drosophila suzukii (Diptera: Drosophilidae), spotted wing drosophila, is an invasive agricultural pest worldwide. Its ability to overwinter and therefore establish in temperate regions could have severe implications for fruit crop industries. We demonstrate here that laboratory populations of Canadian D. suzukii larvae reared under short-day, low temperature, conditions develop into dark 'winter morph' adults similar to those reported globally from field captures, and observed by us in southern Ontario, Canada. These winter-acclimated adults have delayed reproductive maturity, enhanced cold tolerance, and can remain active at low temperatures, although they do not have the increased desiccation tolerance or survival of fungal pathogen challenges that might be expected from a more heavily melanised cuticle. Winter-acclimated female D. suzukii have underdeveloped ovaries and altered transcript levels of several genes associated with reproduction and stress. While superficially indicative of reproductive diapause, the delayed reproductive maturity of winter-acclimated D. suzukii appears to be temperature-dependent, not regulated by photoperiod, and is thus unlikely to be 'true' diapause. The traits of this 'winter morph', however, likely facilitate overwintering in southern Canada, and have probably contributed to the global success of this fly as an invasive species. Copyright © 2016 Elsevier Ltd. All rights reserved.

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

Susceptibility to hypoxia and breathing control changes after short-term cold exposures

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Lyudmila T. Kovtun

2013-08-01

Full Text Available Background . Hypoxia is the reduction of oxygen availability due to external or internal causes. There is large individual variability of response to hypoxia. Objective . The aim of this study was to define individual and typological features in susceptibility to hypoxia, its interrelation with hypoxic and hypercapnic ventilatory responses (HVR and HCVR, respectively and their changes after cold acclimation. Design . Twenty-four healthy men were tested. HVR and HCVR were measured by the rebreathing method during hypoxic and hypercapnic tests, respectively. These tests were carried out in thermoneutral conditions before and after cold exposures (nude, at 13°C, 2 h daily, for 10 days. Susceptibility to hypoxia (sSaO2 was determined as haemoglobin saturation slope during hypoxic test. Results . It was found that HVR and HCVR significantly increased and susceptibility to hypoxia (sSaO2 tended to decrease after cold acclimation. According to sSaO2 results before cold exposures, the group was divided into 3: Group 1 – with high susceptibility to hypoxia, Group 2 – medium and Group 3 – low susceptibility. Analysis of variances (MANOVA shows the key role of susceptibility to hypoxia and cold exposures and their interrelation. Posterior analysis (Fisher LSD showed significant difference in susceptibility to hypoxia between the groups prior to cold acclimation, while HVR and HCVR did not differ between the groups. After cold acclimation, susceptibility to hypoxia was not significantly different between the groups, while HCVR significantly increased in Groups 1 and 3, HVR significantly increased in Group 3 and HCVR, HVR did not change in Group 2. Conclusions . Short-term cold exposures caused an increase in functional reserves and improved oxygen supply of tissues in Group 1. Cold exposure hypoxia has caused energy loss in Group 3. Group 2 showed the most appropriate energy conservation reaction mode to cold exposures. No relation was found between

Cold-acclimation leads to differential regulation of the steelhead trout (Oncorhynchus mykiss) coronary microcirculation

Science.gov (United States)

Costa, Isabel A. S. F.; Hein, Travis W.

2015-01-01

The regulation of vascular resistance in fishes has largely been studied using isolated large conductance vessels, yet changes in tissue perfusion/vascular resistance are primarily mediated by the dilation/constriction of small arterioles. Thus we adapted mammalian isolated microvessel techniques for use in fish and examined how several agents affected the tone/resistance of isolated coronary arterioles (trout (Oncorhynchus mykiss) acclimated to 1, 5, and 10°C. At 10°C, the vessels showed a concentration-dependent dilation to adenosine (ADE; 61 ± 8%), sodium nitroprusside (SNP; 35 ± 10%), and serotonin (SER; 27 ± 2%) (all values maximum responses). A biphasic response (mild contraction then dilation) was observed in vessels exposed to increasing concentrations of epinephrine (EPI; 34 ± 9% dilation) and norepinephrine (NE; 32 ± 7% dilation), whereas the effect was less pronounced with bradykinin (BK; 12.5 ± 3.5% constriction vs. 6 ± 6% dilation). Finally, a mild constriction was observed after exposure to acetylcholine (ACh; 6.5 ± 1.4%), while endothelin (ET)-1 caused a strong dose-dependent increase in tone (79 ± 5% constriction). Acclimation temperature had varying effects on the responsiveness of vessels. The dilations induced by EPI, ADE, SER, and SNP were reduced/eliminated at 5°C and/or 1°C as compared with 10°C. In contrast, acclimation to 5 and 1°C increased the maximum constriction induced by ACh and the sensitivity of vessels to ET-1 (but not the maximum response) at 1°C was greater. Acclimation temperature had no effect on the response to NE, and responsiveness to BK was variable. PMID:25715834

Biochemical and molecular characterization of the antioxidative system of Coffea sp. under cold conditions in genotypes with contrasting tolerance.

Science.gov (United States)

Fortunato, Ana S; Lidon, Fernando C; Batista-Santos, Paula; Leitão, António Eduardo; Pais, Isabel P; Ribeiro, Ana I; Ramalho, José Cochicho

2010-03-15

Low positive temperature (chilling) is frequently linked to the promotion of oxidative stress conditions, and is of particular importance in the coffee plant due to its severe impact on growth, development, photosynthesis and production. Nevertheless, some acclimation ability has been reported within the Coffea genus, and is possibly related to oxidative stress control. Using an integrated biochemical and molecular approach, the characterization of the antioxidative system of genotypes with different cold acclimation abilities was performed. Experiments were carried out using 1.5-year-old coffee seedlings of Coffea canephora cv. Apoatã, C. arabica cv. Catuaí, C. dewevrei and 2 hybrids, Icatu (C. arabicaxC. canephora) and Piatã (C. dewevreixC. arabica) subjected to a gradual cold treatment and a recovery period. Icatu showed the greatest ability to control oxidative stress, as reflected by the enhancement of several antioxidative components (Cu,Zn-SOD and APX activities; ascorbate, alpha-tocopherol and chlorogenic acids (CGAs) contents) and lower reactive oxygen species contents (H(2)O(2) and OH). Gene expression studies show that GRed, DHAR and class III and IV chitinases might also be involved in the cold acclimation ability of Icatu. Catuaí showed intermediate acclimation ability through the reinforcement of some antioxidative molecules, usually to a lesser extent than that observed in Icatu. On the other hand, C. dewevrei showed the poorest response in terms of antioxidant accumulation, and also showed the greatest increase in OH values. The difference in the triggering of antioxidative traits supports the hypothesis of its importance to cold (and photoinhibition) tolerance in Coffea sp. and could provide a useful probe to identify tolerant genotypes. Copyright 2009 Elsevier GmbH. All rights reserved.

Cold hardiness increases with age in juvenile Rhododendron populations

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Rajeev eArora

2014-10-01

Full Text Available Winter survival in woody plants is controlled by environmental and genetic factors that affect the plant's ability to cold acclimate. Because woody perennials are long-lived and often have a prolonged juvenile (pre-flowering phase, it is conceivable that both chronological and physiological age factors influence adaptive traits such as stress tolerance. This study investigated annual cold hardiness (CH changes in several hybrid Rhododendron populations based on Tmax, an estimate of the maximum rate of freezing injury (ion leakage in cold-acclimated leaves from juvenile progeny. Data from F2 and backcross populations derived from R. catawbiense and R. fortunei parents indicated significant annual increases in Tmax ranging from 3.7 to to 6.4 C as the seedlings aged from 3 to 5 years old. A similar yearly increase (6.7° C was observed in comparisons of 1- and 2-year-old F1 progenies from a R. catawbiense x R. dichroanthum cross. In contrast, CH of the mature parent plants (> 10 years old did not change significantly over the same evaluation period. In leaf samples from a natural population of R. maximum, CH evaluations over two years resulted in an average Tmax value for juvenile 2- to 3- year- old plants that was 9.2 C lower than the average for mature (~30 years old plants. . A reduction in CH was also observed in three hybrid rhododendron cultivars clonally propagated by rooted cuttings (ramets - Tmax of 4-year-old ramets was significantly lower than the Tmax estimates for the 30- to 40-year-old source plants (ortets. In both the wild R. maximum population and the hybrid cultivar group, higher accumulation of a cold-acclimation responsive 25kDa leaf dehydrin was associated with older plants and higher CH. The feasibility of identifying hardy phenotypes at juvenile period and research implications of age-dependent changes in CH are discussed.

Sll0528, a Site-2-Protease, Is Critically Involved in Cold, Salt and Hyperosmotic Stress Acclimation of Cyanobacterium Synechocystis sp. PCC 6803

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Haijin Lei

2014-12-01

Full Text Available Site-2-proteases (S2Ps mediated proteolysis of transmembrane transcriptional regulators is a conserved mechanism to regulate transmembrane signaling. The universal presence of S2P homologs in different cyanobacterial genomes suggest conserved and fundamental functions, though limited data has been available. Here we provide the first evidence that Sll0528, a site-2-protease in Synechocystis sp. PCC 6803 is crucial for salt, cold and hyperosmotic stress acclimation. Remarkable induction of sll0528 gene expression was observed under salt, cold and hyperosmotic stress, much higher than induction of the other three S2Ps. Knock-out of sll0528 gene in wild type Synechocystis sp. PCC 6803 increased their sensitivity to salt, cold and hyperosmotic stress, as revealed by retarded growth, reduced pigments and disrupted photosystems. The sll0528 gene was induced to a much smaller extent by high light and mixotrophic growth with glucose. Similar growth responses of the sll0528 knockout mutant and wild type under high light and mixotrophic growth indicated that sll0528 was dispensable for these conditions. Recombinant Sll0528 protein could cleave beta-casein into smaller fragments. These results together suggest that the Sll0528 metalloprotease plays a role in the stress response and lays the foundation for further investigation of its mechanism, as well as providing hints for the functional analysis of other S2Ps in cyanobacteria.

Pleiotropic effect of chromosome 5A and the mvp mutation on the metabolite profile during cold acclimation and the vegetative/generative transition in wheat.

Science.gov (United States)

Juhász, Zsófia; Boldizsár, Ákos; Nagy, Tibor; Kocsy, Gábor; Marincs, Ferenc; Galiba, Gábor; Bánfalvi, Zsófia

2015-02-19

Wheat is the leading source of vegetable protein in the human diet, and metabolites are crucial for both plant development and human nutrition. The recent advances in metabolomics provided an opportunity to perform an untargeted metabolite analysis in this important crop. Wheat was characterised at the metabolite level during cold acclimation and transition from the vegetative to the generative phase. The relationship between these changes and chromosome 5A and the maintained vegetative phase (mvp) mutation was also investigated. Samples were taken from the shoots and crowns during four developmental stages: plants grown at 20/17°C, after cold treatment but still during the vegetative phase, at the double ridge and during spikelet formation. The levels of 47 compounds were identified by gas chromatography-mass spectrometry, of which 38 were annotated. The cold treatment, in general, increased the concentrations of osmolites but not in all lines and not equally in the shoots and crowns. The accumulation of proline was not associated with the vernalisation process or with frost tolerance. The mvp mutation and chromosome 5A substitutions altered the amounts of several metabolites compared to those of the Tm and CS, respectively, during each developmental stage. The Ch5A substitution resulted in more substantial changes at the metabolite level than did the Tsp5A substitution. While Ch5A mainly influenced the sugar concentrations, Tsp5A altered the level of tricarboxylic acid cycle intermediates during the vegetative/generative transition. A much higher trehalose, proline, glutamine, asparagine, and unidentified m/z 186 content was detected in crowns than in shoots that may contribute to the frost tolerance of crowns. Substantial influences of chromosome 5A and the mvp mutation on metabolism during four different developmental stages were demonstrated. The distinct and overlapping accumulation patterns of metabolites suggest the complex genetic regulation of metabolism

Survey on Mycoplasma hyopneumoniae gilt acclimation practices in Europe.

Science.gov (United States)

Garza-Moreno, Laura; Segalés, Joaquim; Pieters, Maria; Romagosa, Anna; Sibila, Marina

2017-01-01

Gilts are considered to play a key role in Mycoplasma hyopneumoniae (M. hyopneumoniae) transmission and control. An effective gilt acclimation program should ideally reduce M. hyopneumoniae shedding at first farrowing, decreasing pre-weaning colonization prevalence and potential respiratory problems in fatteners. However, information on gilt acclimation practices is scarce in Europe . The aim of this study was to identify current acclimation strategies for M. hyopneumoniae in Europe using a questionnaire designed to assess 15 questions focused on gilt replacement status, acclimation strategies and methods used to ascertain its effect. A total of 321 questionnaires (representing 321 farms) were voluntarily completed by 108 veterinarians (from 18 European countries). From these farms, 280 out of 321 (87.2%) were aware of the health status of gilts on arrival. From these 280 farms, 161 (57.5%) introduced M. hyopneumoniae positive replacements. In addition, 249 out of 321 (77.6%) farms applied an acclimation process using different strategies, being M. hyopneumoniae vaccination (145 out of 249, 58.2%) and the combination of vaccine and exposure to sows selected for slaughter (53 out of 249, 21.3%) the most commonly used. Notwithstanding, only 53 out of 224 (23.6%) farms, knowing the M. hyopneumoniae initial status and performing acclimation strategies against it, verified the effect of the acclimation by ELISA (22 out of 53, 41.5%), PCR (4 out of 53, 7.5%) or both (27 out of 53, 50.9%). This study showed that three fourths of the farms represented in this European survey have M. hyopneumoniae acclimation strategies for gilts, and one fifth of them verify to some extent the effect of the process. Taking into account that the assessment of acclimation efficacy could help in optimizing replacement gilt introduction into the breeding herd, it seems these practices for M. hyopneumoniae are still poorly developed in Europe.

Plant resistance to cold stress: Mechanisms and environmental ...

Indian Academy of Sciences (India)

Unknown

Cold acclimation of plants; environmental signals; frost hardening; photoperiod; phytochrome; Scots pine http://www.ias.ac.in/jbiosci .... radical scavenging potential of the cells (Tao et al 1998; ...... tion in cell–free extracts; FEBS Lett. 410 206– ...

Temperature studies with the Asian citrus psyllid, Diaphorina citri: cold hardiness and temperature thresholds for oviposition.

Science.gov (United States)

Hall, David G; Wenninger, Erik J; Hentz, Matthew G

2011-01-01

This study was conducted to obtain information on the cold hardiness of the Asian citrus psyllid, Diaphorina citri Kuwayama (Hemiptera: Psyllidae), in Florida and to assess upper and lower temperature thresholds for oviposition. The psyllid is an important pest in citrus because it transmits the bacterial pathogens responsible for citrus greening disease, Huanglongbing, considered the most serious citrus disease worldwide. D. citri was first found in Florida during 1998, and the disease was discovered during 2005. Little was known regarding cold hardiness of D. citri, but Florida citrus is occasionally subjected to notable freeze events. Temperature and duration were each significant sources of variation in percent mortality of D. citri subjected to freeze events. Relatively large percentages of adults and nymphs survived after being exposed for several hours to temperatures as low as -5 to -6 °C. Relatively large percentages of eggs hatched after being exposed for several hours to temperatures as low as -8 °C. Research results indicated that adult D. citri become cold acclimated during the winter through exposure to cooler winter temperatures. There was no evidence that eggs became cold acclimated during winter. Cold acclimation in nymphs was not investigated. Research with adult D. citri from laboratory and greenhouse colonies revealed that mild to moderate freeze events were usually nonlethal to the D. citri irrespective of whether they were cold acclimated or not. Upper and lower temperature thresholds for oviposition were investigated because such information may be valuable in explaining the geographic distribution and potential spread of the pest from Florida as well as how cooler winter temperatures might limit population growth. The estimated lower and upper thresholds for oviposition were 16.0 and 41.6 °C, respectively; the estimated temperature of peak oviposition over a 48 h period was 29.6 °C.

Human whole body cold adaptation.

Science.gov (United States)

Daanen, Hein A M; Van Marken Lichtenbelt, Wouter D

2016-01-01

Reviews on whole body human cold adaptation generally do not distinguish between population studies and dedicated acclimation studies, leading to confusing results. Population studies show that indigenous black Africans have reduced shivering thermogenesis in the cold and poor cold induced vasodilation in fingers and toes compared to Caucasians and Inuit. About 40,000 y after humans left Africa, natives in cold terrestrial areas seems to have developed not only behavioral adaptations, but also physiological adaptations to cold. Dedicated studies show that repeated whole body exposure of individual volunteers, mainly Caucasians, to severe cold results in reduced cold sensation but no major physiological changes. Repeated cold water immersion seems to slightly reduce metabolic heat production, while repeated exposure to milder cold conditions shows some increase in metabolic heat production, in particular non-shivering thermogenesis. In conclusion, human cold adaptation in the form of increased metabolism and insulation seems to have occurred during recent evolution in populations, but cannot be developed during a lifetime in cold conditions as encountered in temperate and arctic regions. Therefore, we mainly depend on our behavioral skills to live in and survive the cold.

Up-regulation of avian uncoupling protein in cold-acclimated and hyperthyroid ducklings prevents reactive oxygen species production by skeletal muscle mitochondria

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Servais Stéphane

2010-04-01

Full Text Available Abstract Background Although identified in several bird species, the biological role of the avian homolog of mammalian uncoupling proteins (avUCP remains extensively debated. In the present study, the functional properties of isolated mitochondria were examined in physiological or pharmacological situations that induce large changes in avUCP expression in duckling skeletal muscle. Results The abundance of avUCP mRNA, as detected by RT-PCR in gastrocnemius muscle but not in the liver, was markedly increased by cold acclimation (CA or pharmacological hyperthyroidism but was down-regulated by hypothyroidism. Activators of UCPs, such as superoxide with low doses of fatty acids, stimulated a GDP-sensitive proton conductance across the inner membrane of muscle mitochondria from CA or hyperthyroid ducklings. The stimulation was much weaker in controls and not observed in hypothyroid ducklings or in any liver mitochondrial preparations. The production of endogenous mitochondrial reactive oxygen species (ROS was much lower in muscle mitochondria from CA and hyperthyroid ducklings than in the control or hypothyroid groups. The addition of GDP markedly increased the mitochondrial ROS production of CA or hyperthyroid birds up to, or above, the level of control or hypothyroid ducklings. Differences in ROS production among groups could not be attributed to changes in antioxidant enzyme activities (superoxide dismutase or glutathione peroxidase. Conclusion This work provides the first functional in vitro evidence that avian UCP regulates mitochondrial ROS production in situations of enhanced metabolic activity.

Up-regulation of avian uncoupling protein in cold-acclimated and hyperthyroid ducklings prevents reactive oxygen species production by skeletal muscle mitochondria.

Science.gov (United States)

Rey, Benjamin; Roussel, Damien; Romestaing, Caroline; Belouze, Maud; Rouanet, Jean-Louis; Desplanches, Dominique; Sibille, Brigitte; Servais, Stéphane; Duchamp, Claude

2010-04-28

Although identified in several bird species, the biological role of the avian homolog of mammalian uncoupling proteins (avUCP) remains extensively debated. In the present study, the functional properties of isolated mitochondria were examined in physiological or pharmacological situations that induce large changes in avUCP expression in duckling skeletal muscle. The abundance of avUCP mRNA, as detected by RT-PCR in gastrocnemius muscle but not in the liver, was markedly increased by cold acclimation (CA) or pharmacological hyperthyroidism but was down-regulated by hypothyroidism. Activators of UCPs, such as superoxide with low doses of fatty acids, stimulated a GDP-sensitive proton conductance across the inner membrane of muscle mitochondria from CA or hyperthyroid ducklings. The stimulation was much weaker in controls and not observed in hypothyroid ducklings or in any liver mitochondrial preparations. The production of endogenous mitochondrial reactive oxygen species (ROS) was much lower in muscle mitochondria from CA and hyperthyroid ducklings than in the control or hypothyroid groups. The addition of GDP markedly increased the mitochondrial ROS production of CA or hyperthyroid birds up to, or above, the level of control or hypothyroid ducklings. Differences in ROS production among groups could not be attributed to changes in antioxidant enzyme activities (superoxide dismutase or glutathione peroxidase). This work provides the first functional in vitro evidence that avian UCP regulates mitochondrial ROS production in situations of enhanced metabolic activity.

Acclimation responses to temperature vary with vertical stratification: implications for vulnerability of soil-dwelling species to extreme temperature events.

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van Dooremalen, Coby; Berg, Matty P; Ellers, Jacintha

2013-03-01

The occurrence of summer heat waves is predicted to increase in amplitude and frequency in the near future, but the consequences of such extreme events are largely unknown, especially for belowground organisms. Soil organisms usually exhibit strong vertical stratification, resulting in more frequent exposure to extreme temperatures for surface-dwelling species than for soil-dwelling species. Therefore soil-dwelling species are expected to have poor acclimation responses to cope with temperature changes. We used five species of surface-dwelling and four species of soil-dwelling Collembola that habituate different depths in the soil. We tested for differences in tolerance to extreme temperatures after acclimation to warm and cold conditions. We also tested for differences in acclimation of the underlying physiology by looking at changes in membrane lipid composition. Chill coma recovery time, heat knockdown time and fatty acid profiles were determined after 1 week of acclimation to either 5 or 20 °C. Our results showed that surface-dwelling Collembola better maintained increased heat tolerance across acclimation temperatures, but no such response was found for cold tolerance. Concordantly, four of the five surface-dwelling Collembola showed up to fourfold changes in relative abundance of fatty acids after 1 week of acclimation, whereas none of the soil-dwelling species showed a significant adjustment in fatty acid composition. Strong physiological responses to temperature fluctuations may have become redundant in soil-dwelling species due to the relative thermal stability of their subterranean habitat. Based on the results of the four species studied, we expect that unless soil-dwelling species can temporarily retreat to avoid extreme temperatures, the predicted increase in heat waves under climatic change renders these soil-dwelling species more vulnerable to extinction than species with better physiological capabilities. Being able to act under a larger thermal

RNA-Seq-based analysis of cold shock response in Thermoanaerobacter tengcongensis, a bacterium harboring a single cold shock protein encoding gene.

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Bo Liu

Full Text Available BACKGROUND: Although cold shock responses and the roles of cold shock proteins in microorganisms containing multiple cold shock protein genes have been well characterized, related studies on bacteria possessing a single cold shock protein gene have not been reported. Thermoanaerobacter tengcongensis MB4, a thermophile harboring only one known cold shock protein gene (TtescpC, can survive from 50° to 80 °C, but has poor natural competence under cold shock at 50 °C. We therefore examined cold shock responses and their effect on natural competence in this bacterium. RESULTS: The transcriptomes of T. tengcongensis before and after cold shock were analyzed by RNA-seq and over 1200 differentially expressed genes were successfully identified. These genes were involved in a wide range of biological processes, including modulation of DNA replication, recombination, and repair; energy metabolism; production of cold shock protein; synthesis of branched amino acids and branched-chain fatty acids; and sporulation. RNA-seq analysis also suggested that T. tengcongensis initiates cell wall and membrane remodeling processes, flagellar assembly, and sporulation in response to low temperature. Expression profiles of TtecspC and failed attempts to produce a TtecspC knockout strain confirmed the essential role of TteCspC in the cold shock response, and also suggested a role of this protein in survival at optimum growth temperature. Repression of genes encoding ComEA and ComEC and low energy metabolism levels in cold-shocked cells are the likely basis of poor natural competence at low temperature. CONCLUSION: Our study demonstrated changes in global gene expression under cold shock and identified several candidate genes related to cold shock in T. tengcongensis. At the same time, the relationship between cold shock response and poor natural competence at low temperature was preliminarily elucidated. These findings provide a foundation for future studies on genetic

Effects of freezing and cold acclimation on the plasma membrane of isolated protoplasts. Summary progress report, May 16, 1987--June 1, 1991

Energy Technology Data Exchange (ETDEWEB)

Steponkus, P.L.

1991-12-31

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.

Effect of short-term exercise-heat acclimation on ventilatory and cerebral blood flow responses to passive heating at rest in humans.

Science.gov (United States)

Fujii, Naoto; Tsuji, Bun; Honda, Yasushi; Kondo, Narihiko; Nishiyasu, Takeshi

2015-09-01

Hyperthermia induces hyperventilation and cerebral hypoperfusion in resting humans. We tested the hypothesis that short-term exercise-heat acclimation would alleviate those effects. Twenty healthy male subjects were divided into two groups that performed exercise training in the heat (TR-HEAT, n = 10) or cold (TR-COLD, n = 10). Before and after the training, the subjects in both groups participated in passive-heat tests at rest. Training was performed at 37°C (TR-HEAT) or 10°C (TR-COLD) and entailed four 20-min bouts of cycling at 50% peak oxygen uptake separated by 10-min recoveries daily for 6 consecutive days. After TR-HEAT, esophageal temperature was lowered when measured before and during passive heating, as was the esophageal temperature threshold for cutaneous active vasodilation, whereas plasma volume was increased (all P heat acclimation were not all induced by TR-COLD (all P > 0.05). TR-HEAT had no significant effect on passive heating-induced increases in minute ventilation, even when evaluated as the esophageal temperature threshold for increases in minute ventilation and the slope relating minute ventilation to esophageal temperature (all P > 0.05). By contrast, TR-HEAT attenuated the passive heating-induced reduction in the cerebral vascular conductance index (middle cerebral artery mean blood velocity/mean arterial pressure) (all P heating (all P > 0.05). These data suggest that in resting heated humans, short-term heat acclimation achieved through moderate-intensity exercise training (i.e., 50% peak oxygen uptake) in the heat does not influence hyperthermia-induced hyperventilation, but it does potentially attenuate cerebral hypoperfusion. Copyright © 2015 the American Physiological Society.

End of the century pCO₂ levels do not impact calcification in Mediterranean cold-water corals.

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Cornelia Maier

Full Text Available Ocean acidification caused by anthropogenic uptake of CO₂ is perceived to be a major threat to calcifying organisms. Cold-water corals were thought to be strongly affected by a decrease in ocean pH due to their abundance in deep and cold waters which, in contrast to tropical coral reef waters, will soon become corrosive to calcium carbonate. Calcification rates of two Mediterranean cold-water coral species, Lophelia pertusa and Madrepora oculata, were measured under variable partial pressure of CO₂ (pCO₂ that ranged between 380 µatm for present-day conditions and 930 µatm for the end of the century. The present study addressed both short- and long-term responses by repeatedly determining calcification rates on the same specimens over a period of 9 months. Besides studying the direct, short-term response to elevated pCO₂ levels, the study aimed to elucidate the potential for acclimation of calcification of cold-water corals to ocean acidification. Net calcification of both species was unaffected by the levels of pCO₂ investigated and revealed no short-term shock and, therefore, no long-term acclimation in calcification to changes in the carbonate chemistry. There was an effect of time during repeated experiments with increasing net calcification rates for both species, however, as this pattern was found in all treatments, there is no indication that acclimation of calcification to ocean acidification occurred. The use of controls (initial and ambient net calcification rates indicated that this increase was not caused by acclimation in calcification response to higher pCO₂. An extrapolation of these data suggests that calcification of these two cold-water corals will not be affected by the pCO₂ level projected at the end of the century.

Characterization of Medicago populations under cold acclimation by ...

African Journals Online (AJOL)

SAM

2014-07-02

Jul 2, 2014 ... their metabolism and basic cell functioning biophysical constraints imposed by the transition to ... Plant material, growth conditions and cold stress treatment. The study was carried on four annuals ... and the root (LR) were measured at the end of each treatment on both the treated and control lots. LR and ...

UV-B Perception and Acclimation in Chlamydomonas reinhardtii[OPEN

Science.gov (United States)

Chappuis, Richard; Allorent, Guillaume

2016-01-01

Plants perceive UV-B, an intrinsic component of sunlight, via a signaling pathway that is mediated by the photoreceptor UV RESISTANCE LOCUS8 (UVR8) and induces UV-B acclimation. To test whether similar UV-B perception mechanisms exist in the evolutionarily distant green alga Chlamydomonas reinhardtii, we identified Chlamydomonas orthologs of UVR8 and the key signaling factor CONSTITUTIVELY PHOTOMORPHOGENIC1 (COP1). Cr-UVR8 shares sequence and structural similarity to Arabidopsis thaliana UVR8, has conserved tryptophan residues for UV-B photoreception, monomerizes upon UV-B exposure, and interacts with Cr-COP1 in a UV-B-dependent manner. Moreover, Cr-UVR8 can interact with At-COP1 and complement the Arabidopsis uvr8 mutant, demonstrating that it is a functional UV-B photoreceptor. Chlamydomonas shows apparent UV-B acclimation in colony survival and photosynthetic efficiency assays. UV-B exposure, at low levels that induce acclimation, led to broad changes in the Chlamydomonas transcriptome, including in genes related to photosynthesis. Impaired UV-B-induced activation in the Cr-COP1 mutant hit1 indicates that UVR8-COP1 signaling induces transcriptome changes in response to UV-B. Also, hit1 mutants are impaired in UV-B acclimation. Chlamydomonas UV-B acclimation preserved the photosystem II core proteins D1 and D2 under UV-B stress, which mitigated UV-B-induced photoinhibition. These findings highlight the early evolution of UVR8 photoreceptor signaling in the green lineage to induce UV-B acclimation and protection. PMID:27020958

De Novo Assembly and Transcriptome Analysis of Bulb Onion (Allium cepa L.) during Cold Acclimation Using Contrasting Genotypes.

Science.gov (United States)

Han, Jeongsukhyeon; Thamilarasan, Senthil Kumar; Natarajan, Sathishkumar; Park, Jong-In; Chung, Mi-Young; Nou, Ill-Sup

2016-01-01

Bulb onion (Allium cepa) is the second most widely cultivated and consumed vegetable crop in the world. During winter, cold injury can limit the production of bulb onion. Genomic resources available for bulb onion are still very limited. To date, no studies on heritably durable cold and freezing tolerance have been carried out in bulb onion genotypes. We applied high-throughput sequencing technology to cold (2°C), freezing (-5 and -15°C), and control (25°C)-treated samples of cold tolerant (CT) and cold susceptible (CS) genotypes of A. cepa lines. A total of 452 million paired-end reads were de novo assembled into 54,047 genes with an average length of 1,331 bp. Based on similarity searches, these genes were aligned with entries in the public non-redundant (nr) database, as well as KEGG and COG database. Differentially expressed genes (DEGs) were identified using log10 values with the FPKM method. Among 5,167DEGs, 491 genes were differentially expressed at freezing temperature compared to the control temperature in both CT and CS libraries. The DEG results were validated with qRT-PCR. We performed GO and KEGG pathway enrichment analyses of all DEGs and iPath interactive analysis found 31 pathways including those related to metabolism of carbohydrate, nucleotide, energy, cofactors and vitamins, other amino acids and xenobiotics biodegradation. Furthermore, a large number of molecular markers were identified from the assembled genes, including simple sequence repeats (SSRs) 4,437 and SNP substitutions of transition and transversion types of CT and CS. Our study is the first to provide a transcriptome sequence resource for Allium spp. with regard to cold and freezing stress. We identified a large set of genes and determined their DEG profiles under cold and freezing conditions using two different genotypes. These data represent a valuable resource for genetic and genomic studies of Allium spp.

De Novo Assembly and Transcriptome Analysis of Bulb Onion (Allium cepa L. during Cold Acclimation Using Contrasting Genotypes.

Directory of Open Access Journals (Sweden)

Jeongsukhyeon Han

Full Text Available Bulb onion (Allium cepa is the second most widely cultivated and consumed vegetable crop in the world. During winter, cold injury can limit the production of bulb onion. Genomic resources available for bulb onion are still very limited. To date, no studies on heritably durable cold and freezing tolerance have been carried out in bulb onion genotypes. We applied high-throughput sequencing technology to cold (2°C, freezing (-5 and -15°C, and control (25°C-treated samples of cold tolerant (CT and cold susceptible (CS genotypes of A. cepa lines. A total of 452 million paired-end reads were de novo assembled into 54,047 genes with an average length of 1,331 bp. Based on similarity searches, these genes were aligned with entries in the public non-redundant (nr database, as well as KEGG and COG database. Differentially expressed genes (DEGs were identified using log10 values with the FPKM method. Among 5,167DEGs, 491 genes were differentially expressed at freezing temperature compared to the control temperature in both CT and CS libraries. The DEG results were validated with qRT-PCR. We performed GO and KEGG pathway enrichment analyses of all DEGs and iPath interactive analysis found 31 pathways including those related to metabolism of carbohydrate, nucleotide, energy, cofactors and vitamins, other amino acids and xenobiotics biodegradation. Furthermore, a large number of molecular markers were identified from the assembled genes, including simple sequence repeats (SSRs 4,437 and SNP substitutions of transition and transversion types of CT and CS. Our study is the first to provide a transcriptome sequence resource for Allium spp. with regard to cold and freezing stress. We identified a large set of genes and determined their DEG profiles under cold and freezing conditions using two different genotypes. These data represent a valuable resource for genetic and genomic studies of Allium spp.

Bioleaching in batch tests for improving sludge dewaterability and metal removal using Acidithiobacillus ferrooxidans and Acidithiobacillus thiooxidans after cold acclimation.

Science.gov (United States)

Zhou, Qingyang; Gao, Jingqing; Li, Yonghong; Zhu, Songfeng; He, Lulu; Nie, Wei; Zhang, Ruiqin

2017-09-01

Bioleaching is a promising technology for removal of metals from sludge and improvement of its dewaterability. Most of the previous studies of bioleaching were focused on removal of metals; bioleaching in cold environments has not been studied extensively. In this study, Acidithiobacillus ferrooxidans and Acidithiobacillus thiooxidans were acclimated at 15 °C and co-inoculated to explore the optimal conditions for improvement of sludge dewaterability and removal of metals by the sequencing batch reactors. The data show after 6 days of bioleaching at 15 °C, 89.6% of Zn, 72.8% of Cu and 39.4% of Pb were removed and the specific resistance to filtration (SRF) was reduced to ∼12%. In addition, the best conditions for bioleaching are an initial pH of 6, a 15% (v/v) inoculum concentration, and A. thiooxidans and A. ferrooxidans mixed in a ratio of 4:1. We found that bioleaching of heavy metals is closely related to final pH, while the sludge SRF is dominated by other factors. Bioleaching can be completed in 6 days, and the sludge dewaterability and removal of metals at 15 °C meet the requirements of most sewage treatment plants.

Low acclimation capacity of narrow-ranging thermal specialists exposes susceptibility to global climate change.

Science.gov (United States)

Markle, Tricia M; Kozak, Kenneth H

2018-05-01

Thermal acclimation is hypothesized to offer a selective advantage in seasonal habitats and may underlie disparities in geographic range size among closely-related species with similar ecologies. Understanding this relationship is also critical for identifying species that are more sensitive to warming climates. Here, we study North American plethodontid salamanders to investigate whether acclimation ability is associated with species' latitudinal extents and the thermal range of the environments they inhabit. We quantified variation in thermal physiology by measuring standard metabolic rate (SMR) at different test and acclimation temperatures for 16 species of salamanders with varying latitudinal extents. A phylogenetically-controlled Markov chain Monte Carlo generalized linear mixed model (MCMCglmm) was then employed to determine whether there are differences in SMR between wide- and narrow-ranging species at different acclimation temperatures. In addition, we tested for a relationship between the acclimation ability of species and the environmental temperature ranges they inhabit. Further, we investigated if there is a trade-off between critical thermal maximum (CTMax) and thermal acclimation ability. MCMCglmm results show a significant difference in acclimation ability between wide and narrow-ranging temperate salamanders. Salamanders with wide latitudinal distributions maintain or slightly increase SMR when subjected to higher test and acclimation temperatures, whereas several narrow-ranging species show significant metabolic depression. We also found significant, positive relationships between acclimation ability and environmental thermal range, and between acclimation ability and CTMax. Wide-ranging salamander species exhibit a greater capacity for thermal acclimation than narrow-ranging species, suggesting that selection for acclimation ability may have been a key factor enabling geographic expansion into areas with greater thermal variability. Further

Molecular processes of transgenerational acclimation to a warming ocean

KAUST Repository

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

2015-01-01

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.

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.

Development of a model system to identify differences in spring and winter oat.

Science.gov (United States)

Chawade, Aakash; Lindén, Pernilla; Bräutigam, Marcus; Jonsson, Rickard; Jonsson, Anders; Moritz, Thomas; Olsson, Olof

2012-01-01

Our long-term goal is to develop a Swedish winter oat (Avena sativa). To identify molecular differences that correlate with winter hardiness, a winter oat model comprising of both non-hardy spring lines and winter hardy lines is needed. To achieve this, we selected 294 oat breeding lines, originating from various Russian, German, and American winter oat breeding programs and tested them in the field in south- and western Sweden. By assaying for winter survival and agricultural properties during four consecutive seasons, we identified 14 breeding lines of different origins that not only survived the winter but also were agronomically better than the rest. Laboratory tests including electrolytic leakage, controlled crown freezing assay, expression analysis of the AsVrn1 gene and monitoring of flowering time suggested that the American lines had the highest freezing tolerance, although the German lines performed better in the field. Finally, six lines constituting the two most freezing tolerant lines, two intermediate lines and two spring cultivars were chosen to build a winter oat model system. Metabolic profiling of non-acclimated and cold acclimated leaf tissue samples isolated from the six selected lines revealed differential expression patterns of 245 metabolites including several sugars, amino acids, organic acids and 181 hitherto unknown metabolites. The expression patterns of 107 metabolites showed significant interactions with either a cultivar or a time-point. Further identification, characterisation and validation of these metabolites will lead to an increased understanding of the cold acclimation process in oats. Furthermore, by using the winter oat model system, differential sequencing of crown mRNA populations would lead to identification of various biomarkers to facilitate winter oat breeding.

Differential cold-shock resistance among acclimated European mussel populations

NARCIS (Netherlands)

Jansen, J.M.; Wendelaar Bonga, S.E.; Hummel, H.

2007-01-01

To study differential cold-shock resistance of marine mussel populations (Mytilus spp.) from different climatic regions in Europe, we sampled 12 populations, ranging from 43 to 58°N. Minimum critical temperatures for aerobic metabolism (CTmin) were determined before and after 3 months of common

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.

Copper and hypoxia modulate transcriptional and mitochondrial functional-biochemical responses in warm acclimated rainbow trout (Oncorhynchus mykiss)

International Nuclear Information System (INIS)

Sappal, Ravinder; Fast, Mark; Purcell, Sara; MacDonald, Nicole; Stevens, Don; Kibenge, Fred; Siah, Ahmed; Kamunde, Collins

2016-01-01

To survive in changing environments fish utilize a wide range of biological responses that require energy. We examined the effect of warm acclimation on the electron transport system (ETS) enzymes and transcriptional responses to hypoxia and copper (Cu) exposure in fish. Rainbow trout (Oncorhynchus mykiss) were acclimated to cold (11 °C; control) and warm (20 °C) temperatures for 3 weeks followed by exposure to Cu, hypoxia or both for 24 h. Activities of ETS enzyme complexes I-IV (CI–CIV) were measured in liver and gill mitochondria. Analyses of transcripts encoding for proteins involved in mitochondrial respiration (cytochrome c oxidase subunits 4-1 and 2: COX4-1 and COX4-2), metal detoxification/stress response (metallothioneins A and B: MT-A and MT-B) and energy sensing (AMP-activated protein kinase α1: AMPKα1) were done in liver mitochondria, and in whole liver and gill tissues by RT-qPCR. Warm acclimation inhibited activities of ETS enzymes while effects of Cu and hypoxia depended on the enzyme and thermal acclimation status. The genes encoding for COX4-1, COX4-2, MT-A, MT-B and AMPKα1 were strongly and tissue-dependently altered by warm acclimation. While Cu and hypoxia clearly increased MT-A and MT-B transcript levels in all tissues, their effects on COX4-1, COX4-2 and AMPKα1 mRNA levels were less pronounced. Importantly, warm acclimation differentially altered COX4-2/COX4-1 ratio in liver mitochondria and gill tissue. The three stressors showed both independent and joint actions on activities of ETS enzymes and transcription of genes involved in energy metabolism, stress response and metals homeostasis. Overall, we unveiled novel interactive effects that should not be overlooked in real world situations wherein fish normally encounter multiple stress factors. - Highlights: • Joint and individual effects of copper, hypoxia and warm acclimation differ quantitatively. • Energy metabolism genes are differentially altered by multiple stressors. �

A novel behavioral assay for measuring cold sensation in mice.

Science.gov (United States)

Brenner, Daniel S; Golden, Judith P; Gereau, Robert W

2012-01-01

Behavioral models of cold responses are important tools for exploring the molecular mechanisms of cold sensation. To complement the currently cold behavioral assays and allow further studies of these mechanisms, we have developed a new technique to measure the cold response threshold, the cold plantar assay. In this assay, animals are acclimated on a glass plate and a cold stimulus is applied to the hindpaw through the glass using a pellet of compressed dry ice. The latency to withdrawal from the cooled glass is used as a measure of the cold response threshold of the rodents, and the dry ice pellet provides a ramping cold stimulus on the glass that allows the correlation of withdrawal latency values to rough estimates of the cold response threshold temperature. The assay is highly sensitive to manipulations including morphine-induced analgesia, Complete Freund's Adjuvant-induced inflammatory allodynia, and Spinal Nerve Ligation-induced neuropathic allodynia.

Overexpression of a peach CBF gene in apple: a model for understanding the integration of growth, dormancy, and cold hardiness in woody plants

Science.gov (United States)

The timing of cold acclimation and de-acclimation, dormancy, and bud break play an integral role in the life cycle of woody plants. The molecular events that regulate these parameters have been the subject of much study, however, in most studies these events have been investigated independently of ...

Cu uptake and turnover in both Cu-acclimated and non-acclimated rainbow trout (Oncorhynchus mykiss)

DEFF Research Database (Denmark)

Grosell, M.; Hogstrand, C.; Wood, C.M.

1997-01-01

-acclimation clearly involves changes in copper accumulation kinetics in the plasma. The acclimated fish showed a 65% reduced Cu-64 accumulation after 65 h and an increased turnover of Cu in the plasma compared to the non-acclimated fish. Total Cu in the plasma increased by 59% after 3 h of exposure in the non...... aortic catheter. By measuring both Cu-64 accumulation and total Cu concentrations, we were able to analyse the ongoing uptake and turnover of ambient Cu, independent of any Cu already present in the fish. Plasma accounted for at least 90% of the Cu-64 labelled Cu present in the blood and Cu...... h of exposure. Acclimation did not have an unambiguous effect on branchial Cu uptake and differences in branchial uptake could not explain the reduced accumulation in the plasma. The rapidly exchangeable Cu pools were 54% in the gills and 33% in the liver, suggesting a considerable hepatic Cu...

Arabidopsis COLD SHOCK DOMAIN PROTEIN2 is a RNA chaperone that is regulated by cold and developmental signals

International Nuclear Information System (INIS)

Sasaki, Kentaro; Kim, Myung-Hee; Imai, Ryozo

2007-01-01

Bacterial cold shock proteins (CSPs) are RNA chaperones that unwind RNA secondary structures. Arabidopsis COLD SHOCK DOMAIN PROTEIN2 (AtCSP2) contains a domain that is shared with bacterial CSPs. Here we showed that AtCSP2 binds to RNA and unwinds nucleic acid duplex. Heterologous expression of AtCSP2 complemented cold sensitivity of an Escherichia coli csp quadruple mutant, indicating that AtCSP2 function as a RNA chaperone in E. coli. AtCSP2 mRNA and protein levels increased during cold acclimation, but the protein accumulation was most prominent after 10 days of cold treatment. AtCSP2 promoter::GUS transgenic plants revealed that AtCSP2 is expressed only in root and shoot apical regions during vegetative growth but is expressed in reproductive organs such as pollens, ovules and embryos. These data indicated that AtCSP2 is involved in developmental processes as well as cold adaptation. Localization of AtCSP2::GFP in nucleolus and cytoplasm suggested different nuclear and cytosolic RNA targets

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.

A novel behavioral assay for measuring cold sensation in mice.

Directory of Open Access Journals (Sweden)

Daniel S Brenner

Full Text Available Behavioral models of cold responses are important tools for exploring the molecular mechanisms of cold sensation. To complement the currently cold behavioral assays and allow further studies of these mechanisms, we have developed a new technique to measure the cold response threshold, the cold plantar assay. In this assay, animals are acclimated on a glass plate and a cold stimulus is applied to the hindpaw through the glass using a pellet of compressed dry ice. The latency to withdrawal from the cooled glass is used as a measure of the cold response threshold of the rodents, and the dry ice pellet provides a ramping cold stimulus on the glass that allows the correlation of withdrawal latency values to rough estimates of the cold response threshold temperature. The assay is highly sensitive to manipulations including morphine-induced analgesia, Complete Freund's Adjuvant-induced inflammatory allodynia, and Spinal Nerve Ligation-induced neuropathic allodynia.

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

International Nuclear Information System (INIS)

Sappal, Ravinder; Fast, Mark; Stevens, Don; Kibenge, Fred; Siah, Ahmed; Kamunde, Collins

2015-01-01

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

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

Multi-generation cadmium acclimation and tolerance in Daphnia magna Straus

International Nuclear Information System (INIS)

Muyssen, Brita T.A.; Janssen, Colin R.

2004-01-01

The cladoceran Daphnia magna was acclimated for seven generations to cadmium concentrations ranging from 0 (control) to 250 μg/l Cd (corresponding to a free ion activity of 4.60 nM Cd 2+ ). Acute and chronic cadmium tolerance as well as cadmium accumulation were monitored as a function of acclimation time. After two to three generations of acclimation to concentrations ranging from 0.23 to 1.11 nM Cd 2+ increases in acute tolerance were maximal (factor 7.2) and significant. Acclimation for seven generations to the same acclimation concentrations did result in an increased chronic cadmium tolerance (21 days EC 50 values increased). Organisms acclimated to 1.93 nM Cd 2+ were equally or more sensitive than non-acclimated daphnids in acute and chronic toxicity tests. Cadmium contents in D. magna increased significantly as a function of the acclimation concentration. Maximum body burdens of 236±30 μg Cd/g dry weight were measured in organisms exposed to 4.60 nM Cd 2+ , but detoxification mechanisms were only successful up to 82±20 μg Cd/g dry weight as this concentration did not cause major decreases in survival and reproduction in chronic toxicity tests. As the potential positive effect of acclimation on cadmium tolerance disappeared with successive acclimation generations and increasing acclimation concentrations, it is concluded that multi-generation acclimation studies are important for the evaluation of the long-term effects of environmental toxicants. - Multi-generation acclimation studies are important for evaluating long-term effects of aquatic pollutants

Disentangling dormancy and cold-hardiness in wine grape cultivars Cabernet Sauvignon and Chardonnay

Science.gov (United States)

Cold-hardiness of bud and cane tissue was monitored throughout para, endo and ecodormancy in field-grown vines using differential thermal analysis to generate lethal temperature exotherms (LTE). Deacclimation and re-acclimation rates were measured during ecodormancy to determine the depth of dorm...

A simple and inexpensive method for determining cold sensitivity and adaptation in mice.

Science.gov (United States)

Brenner, Daniel S; Golden, Judith P; Vogt, Sherri K; Gereau, Robert W

2015-03-17

Cold hypersensitivity is a serious clinical problem, affecting a broad subset of patients and causing significant decreases in quality of life. The cold plantar assay allows the objective and inexpensive assessment of cold sensitivity in mice, and can quantify both analgesia and hypersensitivity. Mice are acclimated on a glass plate, and a compressed dry ice pellet is held against the glass surface underneath the hindpaw. The latency to withdrawal from the cooling glass is used as a measure of cold sensitivity. Cold sensation is also important for survival in regions with seasonal temperature shifts, and in order to maintain sensitivity animals must be able to adjust their thermal response thresholds to match the ambient temperature. The Cold Plantar Assay (CPA) also allows the study of adaptation to changes in ambient temperature by testing the cold sensitivity of mice at temperatures ranging from 30 °C to 5 °C. Mice are acclimated as described above, but the glass plate is cooled to the desired starting temperature using aluminum boxes (or aluminum foil packets) filled with hot water, wet ice, or dry ice. The temperature of the plate is measured at the center using a filament T-type thermocouple probe. Once the plate has reached the desired starting temperature, the animals are tested as described above. This assay allows testing of mice at temperatures ranging from innocuous to noxious. The CPA yields unambiguous and consistent behavioral responses in uninjured mice and can be used to quantify both hypersensitivity and analgesia. This protocol describes how to use the CPA to measure cold hypersensitivity, analgesia, and adaptation in mice.

Linking the salt transcriptome with physiological responses of a salt-resistant Populus species as a strategy to identify genes important for stress acclimation.

Science.gov (United States)

Brinker, Monika; Brosché, Mikael; Vinocur, Basia; Abo-Ogiala, Atef; Fayyaz, Payam; Janz, Dennis; Ottow, Eric A; Cullmann, Andreas D; Saborowski, Joachim; Kangasjärvi, Jaakko; Altman, Arie; Polle, Andrea

2010-12-01

To investigate early salt acclimation mechanisms in a salt-tolerant poplar species (Populus euphratica), the kinetics of molecular, metabolic, and physiological changes during a 24-h salt exposure were measured. Three distinct phases of salt stress were identified by analyses of the osmotic pressure and the shoot water potential: dehydration, salt accumulation, and osmotic restoration associated with ionic stress. The duration and intensity of these phases differed between leaves and roots. Transcriptome analysis using P. euphratica-specific microarrays revealed clusters of coexpressed genes in these phases, with only 3% overlapping salt-responsive genes in leaves and roots. Acclimation of cellular metabolism to high salt concentrations involved remodeling of amino acid and protein biosynthesis and increased expression of molecular chaperones (dehydrins, osmotin). Leaves suffered initially from dehydration, which resulted in changes in transcript levels of mitochondrial and photosynthetic genes, indicating adjustment of energy metabolism. Initially, decreases in stress-related genes were found, whereas increases occurred only when leaves had restored the osmotic balance by salt accumulation. Comparative in silico analysis of the poplar stress regulon with Arabidopsis (Arabidopsis thaliana) orthologs was used as a strategy to reduce the number of candidate genes for functional analysis. Analysis of Arabidopsis knockout lines identified a lipocalin-like gene (AtTIL) and a gene encoding a protein with previously unknown functions (AtSIS) to play roles in salt tolerance. In conclusion, by dissecting the stress transcriptome of tolerant species, novel genes important for salt endurance can be identified.

Cadmium accumulation, gill Cd binding, acclimation, and physiological effects during long term sublethal Cd exposure in rainbow trout

Energy Technology Data Exchange (ETDEWEB)

Hollis, L.; McGeer, J.C.; McDonald, D.G.; Wood, C.M. [Department of Biology, McMaster University, Hamilton, Ontario (Canada)

1999-07-01

acclimated fish. Acclimated trout internalized less {sup 109}Cd than control fish, but interpretation was complicated by the possibility of radioisotopic exchange and specific activity dilution in the large 'cold' Cd pool on the gills. We conclude that gill Cd burden is not predictive of mortality in acclimated fish, that the present gill modelling approach does not work in acclimated fish, and that longer term {sup 109}Cd turnover studies are needed for this purpose. (Copyright (c) 1999 Elsevier Science B.V., Amsterdam. All rights reserved.)

Cadmium accumulation, gill Cd binding, acclimation, and physiological effects during long term sublethal Cd exposure in rainbow trout

International Nuclear Information System (INIS)

Hollis, L.; McGeer, J.C.; McDonald, D.G.; Wood, C.M.

1999-01-01

interpretation was complicated by the possibility of radioisotopic exchange and specific activity dilution in the large 'cold' Cd pool on the gills. We conclude that gill Cd burden is not predictive of mortality in acclimated fish, that the present gill modelling approach does not work in acclimated fish, and that longer term 109 Cd turnover studies are needed for this purpose. (Copyright (c) 1999 Elsevier Science B.V., Amsterdam. All rights reserved.)

Thermophysiological adaptations to passive mild heat acclimation

NARCIS (Netherlands)

Pallubinsky, H; Schellen, L; Kingma, B R M; Dautzenberg, B; van Baak, M A; van Marken Lichtenbelt, W D

Passive mild heat acclimation (PMHA) reflects realistic temperature challenges encountered in everyday life. Active heat acclimation, combining heat exposure and exercise, influences several important thermophysiological parameters; for example, it decreases core temperature and enhances heat

Expression analysis and functional characterization of a novel cold-responsive gene CbCOR15a from Capsella bursa-pastoris.

Science.gov (United States)

Zhou, Mingqi; Wu, Lihua; Liang, Jing; Shen, Chen; Lin, Juan

2012-05-01

The cold-responsive (COR) genes involved in C-repeat binding factor signaling pathway function essentially in cold acclimation of higher plants. A novel COR gene CbCOR15a from shepherd's purse (Capsella bursa-pastoris) was predicted to be a homolog of COR15 in Arabidopsis. The analysis of tissue specific expression pattern as well as characterization of the CbCOR15a promoter revealed that the expression of CbCOR15a was induced by coldness not only in leaves and stem but also in roots. Sequence analysis showed that a 909 bp promoter region of CbCOR15a contained two CRT/DRE elements, two ABRE elements, one auxin-responsive TGA-element and one MeJA-responsive CGTCA-motif. In young seedlings the expression of CbCOR15a could be apparently increased by SA, ABA, MeJA and IAA, and transiently increased by GA(3) accompanied by obvious feedback suppression. According to the altered physiological index values in tobacco under cold treatments, the overexpression of CbCOR15a significantly increased the cold tolerance of transgenic tobacco plants. It can be suggested that CbCOR15a was involved in cold response of Capsella bursa-pastoris associated with SA, ABA, MeJA, IAA and GA(3) regulation and confers enhanced cold acclimation in transgenic plants.

Regulation of energy partitioning and alternative electron transport pathways during cold acclimation of lodgepole pine is oxygen dependent.

Science.gov (United States)

Savitch, Leonid V; Ivanov, Alexander G; Krol, Marianna; Sprott, David P; Oquist, Gunnar; Huner, Norman P A

2010-09-01

Second year needles of Lodgepole pine (Pinus contorta L.) were exposed for 6 weeks to either simulated control summer ['summer'; 25 °C/250 photon flux denisty (PFD)], autumn ('autumn'; 15°C/250 PFD) or winter conditions ('winter'; 5 °C/250 PFD). We report that the proportion of linear electron transport utilized in carbon assimilation (ETR(CO2)) was 40% lower in both 'autumn' and 'winter' pine when compared with the 'summer' pine. In contrast, the proportion of excess photosynthetic linear electron transport (ETR(excess)) not used for carbon assimilation within the total ETR(Jf) increased by 30% in both 'autumn' and 'winter' pine. In 'autumn' pine acclimated to 15°C, the increased amounts of 'excess' electrons were directed equally to 21  kPa O2-dependent and 2  kPa O2-dependent alternative electron transport pathways and the fractions of excitation light energy utilized by PSII photochemistry (Φ(PSII)), thermally dissipated through Φ(NPQ) and dissipated by additional quenching mechanism(s) (Φ(f,D)) were similar to those in 'summer' pine. In contrast, in 'winter' needles acclimated to 5 °C, 60% of photosynthetically generated 'excess' electrons were utilized through the 2  kPa O2-dependent electron sink and only 15% by the photorespiratory (21  kPa O2) electron pathway. Needles exposed to 'winter' conditions led to a 3-fold lower Φ(PSII), only a marginal increase in Φ(NPQ) and a 2-fold higher Φ(f,D), which was O2 dependent compared with the 'summer' and 'autumn' pine. Our results demonstrate that the employment of a variety of alternative pathways for utilization of photosynthetically generated electrons by Lodgepole pine depends on the acclimation temperature. Furthermore, dissipation of excess light energy through constitutive non-photochemical quenching mechanisms is O2 dependent.

Cold stress increases salt tolerance of the extremophytes Eutrema salsugineum (Thellungiella salsuginea) and Eutrema (Thellungiella) botschantzevii

NARCIS (Netherlands)

Shamustakimova, A. O.; Leonova, G.; Taranov, V. V.; de Boer, A. H.; Babakov, A. V.

2017-01-01

A comparative study was performed to analyze the effect of cold acclimation on improving the resistance of Arabidopsis thaliana, Eutrema salsugineum and Eutrema botschantzevii plants to salt stress. Shoot FW, sodium and potassium accumulation, metabolite content, expression of proton pump genes

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

International Nuclear Information System (INIS)

Dorts, Jennifer; Kestemont, Patrick; Thézenas, Marie-Laetitia; Raes, Martine; Silvestre, Frédéric

2014-01-01

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

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

A novel cold-inducible zinc finger protein from soybean, SCOF-1, enhances cold tolerance in transgenic plants.

Science.gov (United States)

Kim, J C; Lee, S H; Cheong, Y H; Yoo, C M; Lee, S I; Chun, H J; Yun, D J; Hong, J C; Lee, S Y; Lim, C O; Cho, M J

2001-02-01

Cold stress on plants induces changes in the transcription of cold response genes. A cDNA clone encoding C2H2-type zinc finger protein, SCOF-1, was isolated from soybean. The transcription of SCOF-1 is specifically induced by low temperature and abscisic acid (ABA) but not by dehydration or high salinity. Constitutive overexpression of SCOF-1 induced cold-regulated (COR) gene expression and enhanced cold tolerance of non-acclimated transgenic Arabidopsis and tobacco plants. SCOF-1 localized to the nucleus but did not bind directly to either C-repeat/dehydration (CRT/DRE) or ABA responsive element (ABRE), cis-acting DNA regulatory elements present in COR gene promoters. However, SCOF-1 greatly enhanced the DNA binding activity of SGBF-1, a soybean G-box binding bZIP transcription factor, to ABRE in vitro. SCOF-1 also interacted with SGBF-1 in a yeast two-hybrid system. The SGBF-1 transactivated the beta-glucuronidase reporter gene driven by the ABRE element in Arabidopsis leaf protoplasts. Furthermore, the SCOF-1 enhanced ABRE-dependent gene expression mediated by SGBF-1. These results suggest that SCOF-1 may function as a positive regulator of COR gene expression mediated by ABRE via protein-protein interaction, which in turn enhances cold tolerance of plants.

The epigenetic landscape of transgenerational acclimation to ocean warming

KAUST Repository

Ryu, Tae Woo; Veilleux, Heather D.; Donelson, Jennifer M.; Munday, Philip L.; Ravasi, Timothy

2018-01-01

Epigenetic inheritance is a potential mechanism by which the environment in one generation can influence the performance of future generations1. Rapid climate change threatens the survival of many organisms; however, recent studies show that some species can adjust to climate-related stress when both parents and their offspring experience the same environmental change2,3. Whether such transgenerational acclimation could have an epigenetic basis is unknown. Here, by sequencing the liver genome, methylomes and transcriptomes of the coral reef fish, Acanthochromis polyacanthus, exposed to current day (+0 °C) or future ocean temperatures (+3 °C) for one generation, two generations and incrementally across generations, we identified 2,467 differentially methylated regions (DMRs) and 1,870 associated genes that respond to higher temperatures within and between generations. Of these genes, 193 were significantly correlated to the transgenerationally acclimating phenotypic trait, aerobic scope, with functions in insulin response, energy homeostasis, mitochondrial activity, oxygen consumption and angiogenesis. These genes may therefore play a key role in restoring performance across generations in fish exposed to increased temperatures associated with climate change. Our study is the first to demonstrate a possible association between DNA methylation and transgenerational acclimation to climate change in a vertebrate.

The epigenetic landscape of transgenerational acclimation to ocean warming

KAUST Repository

Ryu, Tae Woo

2018-04-26

Epigenetic inheritance is a potential mechanism by which the environment in one generation can influence the performance of future generations1. Rapid climate change threatens the survival of many organisms; however, recent studies show that some species can adjust to climate-related stress when both parents and their offspring experience the same environmental change2,3. Whether such transgenerational acclimation could have an epigenetic basis is unknown. Here, by sequencing the liver genome, methylomes and transcriptomes of the coral reef fish, Acanthochromis polyacanthus, exposed to current day (+0 °C) or future ocean temperatures (+3 °C) for one generation, two generations and incrementally across generations, we identified 2,467 differentially methylated regions (DMRs) and 1,870 associated genes that respond to higher temperatures within and between generations. Of these genes, 193 were significantly correlated to the transgenerationally acclimating phenotypic trait, aerobic scope, with functions in insulin response, energy homeostasis, mitochondrial activity, oxygen consumption and angiogenesis. These genes may therefore play a key role in restoring performance across generations in fish exposed to increased temperatures associated with climate change. Our study is the first to demonstrate a possible association between DNA methylation and transgenerational acclimation to climate change in a vertebrate.

Preliminary acclimation strategies for successful startup in conventional biofilters.

Science.gov (United States)

Elías, Ana; Barona, Astrid; Gallastegi, Gorka; Rojo, Naiara; Gurtubay, Luis; Ibarra-Berastegi, Gabriel

2010-08-01

The question of how to obtain the best inocula for conventional biofilters arises when an acclimation/adaptation procedure is to be applied. Bearing in mind that no standardized procedure for acclimating inocula exists, certain preliminary strategies for obtaining an active inoculum from wastewater treatment sludge are proposed in this work. Toluene was the contaminant to be degraded. Concerning the prior separation of sludge phases, no obvious advantage was found in separating the supernatant phase of the sludge before acclimation. As far as a continuous or discontinuous acclimation mode is concerned, the latter is recommended for rapidly obtaining acclimated sludge samples by operating the system for no longer than 1 month. The continuous mode rendered similar degradation rates, although it required longer operating time. Nevertheless, the great advantage of the continuous system lay in the absence of daily maintenance and the ready availability of the activated sample.

Heat death in the crayfish Austropotamobius pallipes: thermal inactivation of muscle membrane-bound ATPases in warm and cold adapted animals

Energy Technology Data Exchange (ETDEWEB)

Gladwell, R T

1976-01-01

The thermal sensitivity of the membrane-bound Mg/sup 2 +/ and Na/sup +/ + K/sup +/ + Mg/sup 2 +/ ATPases from the abdominal flexor muscles of 10 and 25/sup 0/C acclimated animals was investigated. The Mg/sup 2 +/ ATPase was inactivated by milder heat treatments than the Na/sup +/ + K/sup +/ + Mg/sup 2 +/ ATPase. The effect of high lethal temperatures on the Mg/sup 2 +/ ATPase was dependent on the previous thermal history of the animal, the enzyme preparations from 10/sup 0/C acclimated animals being more sensitive than those from 25/sup 0/C acclimated animals. The thermal sensitivity of the Na/sup +/ + K/sup +/ + Mg/sup 2 +/ ATPase was not altered by temperature acclimation. The change in the thermal sensitivity of the Mg/sup 2 +/ ATPase with the acclimation temperature of the whole animal was correlated with the survival times of 10 and 25/sup 0/C acclimated animals. The K/sub m/ and V/sub max/ of the ATPases was investigated and the K/sub m/ of both enzymes was found to decrease with acclimation of the whole animal to lower temperatures, so that enzyme/substrate affinity increased with cold acclimation. It was concluded that the inactivation of the muscle Mg/sup 2 +/ ATPase was the primary lesion of heat death in the crayfish, and that the changes in the kinetic properties of the ATPases were an important mechanism in the process of physiological temperature acclimation.

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

Directory of Open Access Journals (Sweden)

Jennifer M Donelson

Full Text Available 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.

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

2016-03-01

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 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 pointsSome 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.

Exposure of embryos to cyclically cold incubation temperatures durably affects energy metabolism and antioxidant pathways in broiler chickens.

Science.gov (United States)

Loyau, T; Collin, A; Yenisey, C; Crochet, S; Siegel, P B; Akşit, M; Yalçin, S

2014-08-01

Cyclically cold incubation temperatures have been suggested as a means to improve resistance of broiler chickens to ascites; however, the underlying mechanisms are not known. Nine hundred eggs obtained from 48 wk Ross broiler breeders were randomly assigned to 2 incubation treatments: control I eggs were incubated at 37.6°C throughout, whereas for cold I eggs the incubation temperature was reduced by 1°C for 6 h daily from 10 to 18 d of incubation. Thereafter, chickens were reared at standard temperatures or under cold exposure that was associated or not with a postnatal cold acclimation at d 5 posthatch. At hatch, hepatic catalase activity and malondialdehyde content were measured. Serum thyroid hormone and triglyceride concentrations, and muscle expression of several genes involved in the regulation of energy metabolism and oxidative stress were also measured at hatch and 5 and 25 d posthatch. Cold incubation induced modifications in antioxidant pathways with higher catalase activity, but lower expression of avian uncoupling protein 3 at hatch. However, long-term enhancement in the expression of avian uncoupling protein 3 was observed, probably caused by an increase in the expression of the transcription factor peroxisome proliferator activated receptor-γ coactivator-1α. These effects were not systematically associated with an increase in serum triiodothyronine concentrations that were observed only in chickens exposed to both cold incubation and later acclimation at 5 d with cold rearing. Our results suggest that these conditions of cyclically cold incubation resulted in the long-term in changes in antioxidant pathways and energy metabolism, which could enhance the health of chickens reared under cold conditions. © Poultry Science Association Inc.

Branchial Expression Patterns of Claudin Isoforms in Atlantic Salmon During Seawater Acclimation and Smoltification

DEFF Research Database (Denmark)

Tipsmark, Christian K; Kiilerich, Pia; Nilsen, Tom O

2008-01-01

in epithelia. We identified Atlantic salmon genes belonging to the claudin family by screening expressed sequence tag libraries available at NCBI and classification was performed with aid of maximum likelihood and neighbour-joining analysis. In gill libraries, five isoforms (10e, 27a, 28a, 28b and 30) were...... present and QPCR analysis confirmed tissue-specific expression in gill when compared to kidney, intestine, heart, muscle, brain and liver. Expression patterns during acclimation of freshwater salmon to seawater (SW) and during the smoltification process were examined. Acclimation to SW reduced...... induced no significant changes in expression of the other isoforms. This study demonstrates the expression of an array of salmon claudin isoforms and shows that SW acclimation involves inverse regulation, in the gill, of claudin 10e versus claudin 27a and 30. It is possible, that claudin 10e...

Physiology of diapause and cold hardiness in the overwintering pupae of the fall webworm Hyphantria cunea (Lepidoptera: Arctiidae) in Japan.

Science.gov (United States)

Li, Y -P.; Goto, M; Ito, S; Sato, Y; Sasaki, K; Goto, N

2001-09-01

The fall webworm Hyphantria cunea Drury, which was accidentally introduced to Japan in 1945, overwinters on the ground in pupal diapause. Diapause termination, as indicated by the respiration rate and the period required for adult emergence, began in March and ended in April. Cold hardiness (the ability to survive exposure to -15 degrees C) decreased linearly with diapause development from November to the following April under field conditions. Cold hardiness of diapause pupae (DP) decreased as the acclimation temperature decreased from 15 to -10 degrees C, whereas cold hardiness of non-diapause pupae (NDP) remained high as the acclimation temperature decreased from 5 to -5 degrees C. However, H. cunea in Japan can survive exposure to -5 degrees C for two weeks, whether it is in a diapause or non-diapause state. Trehalose was the main sugar detected in the body, but its level was less than 0.8%. Trehalose levels increased in field-collected pupae from January to March. DP accumulated less trehalose than NDP, as the acclimation temperature was decreased from 5 to -5 degrees C. The alanine content in field-collected pupae increased from November to February. Both diapause and low temperature caused an accumulation of alanine. These results suggest that under field conditions, overwintering pupae of H. cunea in Japan do not accumulate high levels of sugars and polyols and do not develop a high level of cold hardiness. Furthermore, DP do not accumulate high levels of sugars and polyols and their ability to survive exposure to -15 degrees C is not greater than that of NDP. The physiological and biochemical bases of diapause in H. cunea from Japan are discussed.

Linking the Salt Transcriptome with Physiological Responses of a Salt-Resistant Populus Species as a Strategy to Identify Genes Important for Stress Acclimation1[W][OA

Science.gov (United States)

Brinker, Monika; Brosché, Mikael; Vinocur, Basia; Abo-Ogiala, Atef; Fayyaz, Payam; Janz, Dennis; Ottow, Eric A.; Cullmann, Andreas D.; Saborowski, Joachim; Kangasjärvi, Jaakko; Altman, Arie; Polle, Andrea

2010-01-01

To investigate early salt acclimation mechanisms in a salt-tolerant poplar species (Populus euphratica), the kinetics of molecular, metabolic, and physiological changes during a 24-h salt exposure were measured. Three distinct phases of salt stress were identified by analyses of the osmotic pressure and the shoot water potential: dehydration, salt accumulation, and osmotic restoration associated with ionic stress. The duration and intensity of these phases differed between leaves and roots. Transcriptome analysis using P. euphratica-specific microarrays revealed clusters of coexpressed genes in these phases, with only 3% overlapping salt-responsive genes in leaves and roots. Acclimation of cellular metabolism to high salt concentrations involved remodeling of amino acid and protein biosynthesis and increased expression of molecular chaperones (dehydrins, osmotin). Leaves suffered initially from dehydration, which resulted in changes in transcript levels of mitochondrial and photosynthetic genes, indicating adjustment of energy metabolism. Initially, decreases in stress-related genes were found, whereas increases occurred only when leaves had restored the osmotic balance by salt accumulation. Comparative in silico analysis of the poplar stress regulon with Arabidopsis (Arabidopsis thaliana) orthologs was used as a strategy to reduce the number of candidate genes for functional analysis. Analysis of Arabidopsis knockout lines identified a lipocalin-like gene (AtTIL) and a gene encoding a protein with previously unknown functions (AtSIS) to play roles in salt tolerance. In conclusion, by dissecting the stress transcriptome of tolerant species, novel genes important for salt endurance can be identified. PMID:20959419

Comparative proteomic and metabolomic analyses reveal mechanisms of improved cold stress tolerance in bermudagrass (Cynodon dactylon (L.) Pers.) by exogenous calcium.

Science.gov (United States)

Shi, Haitao; Ye, Tiantian; Zhong, Bao; Liu, Xun; Chan, Zhulong

2014-11-01

As an important second messenger, calcium is involved in plant cold stress response, including chilling (Cynodon dactylon (L.) Pers.). Physiological analyses showed that CaCl2 treatment alleviated the reactive oxygen species (ROS) burst and cell damage triggered by chilling stress, via activating antioxidant enzymes, non-enzymatic glutathione antioxidant pool, while EGTA treatment had the opposite effects. Additionally, comparative proteomic analysis identified 51 differentially expressed proteins that were enriched in redox, tricarboxylicacid cycle, glycolysis, photosynthesis, oxidative pentose phosphate pathway, and amino acid metabolisms. Consistently, 42 metabolites including amino acids, organic acids, sugars, and sugar alcohols were regulated by CaCl2 treatment under control and cold stress conditions, further confirming the common modulation of CaCl2 treatment in carbon metabolites and amino acid metabolism. Taken together, this study reported first evidence of the essential and protective roles of endogenous and exogenous calcium in bermudagrass response to cold stress, partially via activation of the antioxidants and modulation of several differentially expressed proteins and metabolic homeostasis in the process of cold acclimation. © 2014 Institute of Botany, Chinese Academy of Sciences.

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.

Chlorophyll fluorescence emission as a reporter on cold tolerance in Arabidopsis thaliana accessions

Czech Academy of Sciences Publication Activity Database

Mishra, Anamika; Mishra, Kumud; Höermiller, I. I.; Heyer, A. G.; Nedbal, Ladislav

2011-01-01

Roč. 6, č. 2 (2011), s. 301-310 ISSN 1559-2316 R&D Projects: GA MŠk(CZ) ED1.1.00/02.0073; GA MŠk OC08055; GA MŠk 2B06068 Institutional research plan: CEZ:AV0Z60870520 Keywords : chlorophyll fluorescence * cold acclimation * electrolyte leakage * high - throughput screening * natural accessions Subject RIV: EH - Ecology, Behaviour

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.

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.

Seasonal acclimation and latitudinal adaptation are of the same magnitude in Mytilus edulis and Mytilus trossulus mitochondrial respiration

DEFF Research Database (Denmark)

Thyrring, Jakob; Bundgård, Amanda Marie; Sejr, Mikael Kristian

2017-01-01

Species distribution models often assume homogeneous physiological performance within a species distribution range. This assumption potentially underestimates the distribution as it neglects physiological plasticity and adaptation among species and populations. Better knowledge on the physiological......% after cold acclimation. Combined, our results show that seasonal variation in mitochondrial respiration is of the same magnitude as large-scale (>1000 km) latitudinal variation. The high respiratory plasticity in Mytilus spp. improves fitness in changing temperature environments and supports their large...

ZmCPK1, a calcium-independent kinase member of the Zea mays CDPK gene family, functions as a negative regulator in cold stress signalling.

Science.gov (United States)

Weckwerth, Philipp; Ehlert, Britta; Romeis, Tina

2015-03-01

Calcium-dependent protein kinases (CDPKs) have been shown to play important roles in plant environmental stress signal transduction. We report on the identification of ZmCPK1 as a member of the maize (Zea mays) CDPK gene family involved in the regulation of the maize cold stress response. Based upon in silico analysis of the Z. mays cv. B73 genome, we identified that the maize CDPK gene family consists of 39 members. Two CDPK members were selected whose gene expression was either increased (Zmcpk1) or decreased (Zmcpk25) in response to cold exposure. Biochemical analysis demonstrated that ZmCPK1 displays calcium-independent protein kinase activity. The C-terminal calcium-binding domain of ZmCPK1 was sufficient to mediate calcium independency of a previously calcium-dependent enzyme in chimeric ZmCPK25-CPK1 proteins. Furthermore, co-transfection of maize mesophyll protoplasts with active full-length ZmCPK1 suppressed the expression of a cold-induced marker gene, Zmerf3 (ZmCOI6.21). In accordance, heterologous overexpression of ZmCPK1 in Arabidopsis thaliana yielded plants with altered acclimation-induced frost tolerance. Our results identify ZmCPK1 as a negative regulator of cold stress signalling in maize. © 2014 John Wiley & Sons Ltd.

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.

Acclimation improves salt stress tolerance in Zea mays plants.

Science.gov (United States)

Pandolfi, Camilla; Azzarello, Elisa; Mancuso, Stefano; Shabala, Sergey

2016-08-20

Plants exposure to low level salinity activates an array of processes leading to an improvement of plant stress tolerance. Although the beneficial effect of acclimation was demonstrated in many herbaceous species, underlying mechanisms behind this phenomenon remain poorly understood. In the present study we have addressed this issue by investigating ionic mechanisms underlying the process of plant acclimation to salinity stress in Zea mays. Effect of acclimation were examined in two parallel sets of experiments: a growth experiment for agronomic assessments, sap analysis, stomatal conductance, chlorophyll content, and confocal laser scanning imaging; and a lab experiment for in vivo ion flux measurements from root tissues. Being exposed to salinity, acclimated plants (1) retain more K(+) but accumulate less Na(+) in roots; (2) have better vacuolar Na(+) sequestration ability in leaves and thus are capable of accumulating larger amounts of Na(+) in the shoot without having any detrimental effect on leaf photochemistry; and (3) rely more on Na(+) for osmotic adjustment in the shoot. At the same time, acclimation affect was not related in increased root Na(+) exclusion ability. It appears that even in a such salt-sensitive species as maize, Na(+) exclusion from uptake is of a much less importance compared with the efficient vacuolar Na(+) sequestration in the shoot. Copyright © 2016 Elsevier GmbH. All rights reserved.

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

Directory of Open Access Journals (Sweden)

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 ].

An inorganic carbon transport system responsible for acclimation specific to air levels of CO2 in Chlamydomonas reinhardtii.

Science.gov (United States)

Wang, Yingjun; Spalding, Martin H

2006-06-27

Many photosynthetic microorganisms acclimate to CO(2) limited environments by induction and operation of CO(2)-concentrating mechanisms (CCMs). Despite their central role in CCM function, inorganic carbon (Ci) transport systems never have been identified in eukaryotic photosynthetic organisms. In the green alga Chlamydomonas reinhardtii, a mutant, pmp1, was described in 1983 with deficiencies in Ci transport, and a Pmp1 protein-associated Ci uptake system has been proposed to be responsible for Ci uptake in low CO(2) (air level)-acclimated cells. However, even though pmp1 represents the only clear genetic link to Ci transport in microalgae and is one of only a very few mutants directly affecting the CCM itself, the identity of Pmp1 has remained unknown. Physiological analyses indicate that C. reinhardtii possesses multiple Ci transport systems responsible for acclimation to different levels of limiting CO(2) and that the Pmp1-associated transport system is required specifically for low (air level) CO(2) acclimation. In the current study, we identified and characterized a pmp1 allelic mutant, air dier 1 (ad1) that, like pmp1, cannot grow in low CO(2) (350 ppm) but can grow either in high CO(2) (5% CO(2)) or in very low CO(2) (<200 ppm). Molecular analyses revealed that the Ad1/Pmp1 protein is encoded by LciB, a gene previously identified as a CO(2)-responsive gene. LciB and three related genes in C. reinhardtii compose a unique gene family that encode four closely related, apparently soluble plastid proteins with no clearly identifiable conserved motifs.

Growth response and acclimation of CO2 exchange characteristics to elevated temperatures in tropical tree seedlings.

Science.gov (United States)

Cheesman, Alexander W; Winter, Klaus

2013-09-01

Predictions of how tropical forests will respond to future climate change are constrained by the paucity of data on the performance of tropical species under elevated growth temperatures. In particular, little is known about the potential of tropical species to acclimate physiologically to future increases in temperature. Seedlings of 10 neo-tropical tree species from different functional groups were cultivated in controlled-environment chambers under four day/night temperature regimes between 30/22 °C and 39/31 °C. Under well-watered conditions, all species showed optimal growth at temperatures above those currently found in their native range. While non-pioneer species experienced catastrophic failure or a substantially reduced growth rate under the highest temperature regime employed (i.e. daily average of 35 °C), growth in three lowland pioneers showed only a marginal reduction. In a subsequent experiment, three species (Ficus insipida, Ormosia macrocalyx, and Ochroma pyramidale) were cultivated at two temperatures determined as sub- and superoptimal for growth, but which resulted in similar biomass accumulation despite a 6°C difference in growth temperature. Through reciprocal transfer and temperature adjustment, the role of thermal acclimation in photosynthesis and respiration was investigated. Acclimation potential varied among species, with two distinct patterns of respiration acclimation identified. The study highlights the role of both inherent temperature tolerance and thermal acclimation in determining the ability of tropical tree species to cope with enhanced temperatures.

Functional characterization of the Hyles euphorbiae hawkmoth transcriptome reveals strong expression of phorbol ester detoxification and seasonal cold hardiness genes.

Science.gov (United States)

Barth, M Benjamin; Buchwalder, Katja; Kawahara, Akito Y; Zhou, Xin; Liu, Shanlin; Krezdorn, Nicolas; Rotter, Björn; Horres, Ralf; Hundsdoerfer, Anna K

2018-01-01

The European spurge hawkmoth, Hyles euphorbiae (Lepidoptera, Sphingidae), has been intensively studied as a model organism for insect chemical ecology, cold hardiness and evolution of species delineation. To understand species isolation mechanisms at a molecular level, this study aims at determining genetic factors underlying two adaptive ecological trait candidates, phorbol ester (TPA) detoxification and seasonal cold acclimation. A draft transcriptome of H. euphorbiae was generated using Illumina sequencing, providing the first genomic resource for the hawkmoth subfamily Macroglossinae. RNA expression levels in tissues of experimental TPA feeding larvae and cooled pupae was compared to levels in control larvae and pupae using 26 bp RNA sequence tag libraries (DeepSuperSAGE). Differential gene expression was assessed by homology searches of the tags in the transcriptome. In total, 389 and 605 differentially expressed transcripts for detoxification and cold hardiness, respectively, could be identified and annotated with proteins. The majority (22 of 28) of differentially expressed detox transcripts of the four 'drug metabolism' enzyme groups (cytochrome P450 (CYP), carboxylesterases (CES), glutathione S-transferases (GST) and lipases) are up-regulated. Triacylglycerol lipase was significantly over proportionally annotated among up-regulated detox transcripts. We record several up-regulated lipases, GSTe2, two CESs, CYP9A21, CYP6BD6 and CYP9A17 as candidate genes for further H. euphorbiae TPA detoxification analyses. Differential gene expression of the cold acclimation treatment is marked by metabolic depression with enriched Gene Ontology terms among down-regulated transcripts almost exclusively comprising metabolism, aerobic respiration and dissimilative functions. Down-regulated transcripts include energy expensive respiratory proteins like NADH dehydrogenase, cytochrome oxidase and ATP synthase. Gene expression patterns show shifts in carbohydrate

Frequent extreme cold exposure and brown fat and cold-induced thermogenesis: a study in a monozygotic twin.

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Maarten J Vosselman

Full Text Available INTRODUCTION: Mild cold acclimation is known to increase brown adipose tissue (BAT activity and cold-induced thermogenesis (CIT in humans. We here tested the effect of a lifestyle with frequent exposure to extreme cold on BAT and CIT in a Dutch man known as 'the Iceman', who has multiple world records in withstanding extreme cold challenges. Furthermore, his monozygotic twin brother who has a 'normal' sedentary lifestyle without extreme cold exposures was measured. METHODS: The Iceman (subject A and his brother (subject B were studied during mild cold (13°C and thermoneutral conditions (31°C. Measurements included BAT activity and respiratory muscle activity by [18F]FDG-PET/CT imaging and energy expenditure through indirect calorimetry. In addition, body temperatures, cardiovascular parameters, skin perfusion, and thermal sensation and comfort were measured. Finally, we determined polymorphisms for uncoupling protein-1 and β3-adrenergic receptor. RESULTS: Subjects had comparable BAT activity (A: 1144 SUVtotal and B: 1325 SUVtotal, within the range previously observed in young adult men. They were genotyped with the polymorphism for uncoupling protein-1 (G/G. CIT was relatively high (A: 40.1% and B: 41.9%, but unlike during our previous cold exposure tests in young adult men, here both subjects practiced a g-Tummo like breathing technique, which involves vigorous respiratory muscle activity. This was confirmed by high [18F]FDG-uptake in respiratory muscle. CONCLUSION: No significant differences were found between the two subjects, indicating that a lifestyle with frequent exposures to extreme cold does not seem to affect BAT activity and CIT. In both subjects, BAT was not higher compared to earlier observations, whereas CIT was very high, suggesting that g-Tummo like breathing during cold exposure may cause additional heat production by vigorous isometric respiratory muscle contraction. The results must be interpreted with caution given the

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

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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.

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

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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. PMID:27242814

Perspective Research Progress in Cold Responses of Capsella bursa-pastoris

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Ali Noman

2017-08-01

Full Text Available Plants respond to cold stress by modulating biochemical pathways and array of molecular events. Plant morphology is also affected by the onset of cold conditions culminating at repression in growth as well as yield reduction. As a preventive measure, cascades of complex signal transduction pathways are employed that permit plants to endure freezing or chilling periods. The signaling pathways and related events are regulated by the plant hormonal activity. Recent investigations have provided a prospective understanding about plant response to cold stress by means of developmental pathways e.g., moderate growth involved in cold tolerance. Cold acclimation assays and bioinformatics analyses have revealed the role of potential transcription factors and expression of genes like CBF, COR in response to low temperature stress. Capsella bursa-pastoris is a considerable model plant system for evolutionary and developmental studies. On different occasions it has been proved that C. bursa-pastoris is more capable of tolerating cold than A. thaliana. But, the mechanism for enhanced low or freezing temperature tolerance is still not clear and demands intensive research. Additionally, identification and validation of cold responsive genes in this candidate plant species is imperative for plant stress physiology and molecular breeding studies to improve cold tolerance in crops. We have analyzed the role of different genes and hormones in regulating plant cold resistance with special reference to C. bursa-pastoris. Review of collected data displays potential ability of Capsella as model plant for improvement in cold stress regulation. Information is summarized on cold stress signaling by hormonal control which highlights the substantial achievements and designate gaps that still happen in our understanding.

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

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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.

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

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Dattolo, Emanuela; Gu, Jenny; Bayer, Philipp E; Mazzuca, Silvia; Serra, Ilia A; Spadafora, Antonia; Bernardo, Letizia; Natali, Lucia; Cavallini, Andrea; Procaccini, Gabriele

2013-01-01

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 shallow (-5 m) and deep (-25 m) portions of a single meadow, (i) we generated two reciprocal Expressed Sequences Tags (EST) 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 to be the most involved in depth acclimation in P. oceanica. Their putative rules in acclimation to depth were discussed.

Dicty_cDB: SSB177 [Dicty_cDB

Lifescience Database Archive (English)

Full Text Available strain AX4, complete sequence. 428 e-116 1 CB293485 |CB293485.1 UCRCS01_06ag01_g1 Washington Navel orange cold acclimate...ered pieces. 42 4.0 1 CB291576 |CB291576.1 UCRCS01_03af02_b1 Washington Navel orange cold acclimated flavedo...42 4.0 1 CB293416 |CB293416.1 UCRCS01_06ac11_b1 Washington Navel orange cold acclimated flavedo & albedo cDN...dg03_g1 Washington Navel orange cold acclimated flavedo & albedo cDNA library Cit

Cold exposure potentiates the effect of insulin on in vivo glucose uptake

International Nuclear Information System (INIS)

Vallerand, A.L.; Perusse, F.; Bukowiecki, L.J.

1987-01-01

The effects of cold exposure and insulin injection on the rates of net 2-[ 3 H]deoxyglucose uptake (K i ) in peripheral tissues were investigated in warm-acclimated rats. Cold exposure and insulin treatment independently increased K i values in skeletal muscles, heart, white adipose tissue, and brown adipose tissue. The effects of cold exposure were particularly evident in brown adipose tissue where the K i increased >100 times. When the two treatments were combined, it was found that cold exposure synergistically enhanced the maximal insulin responses for glucose uptake in brown adipose tissue, all white adipose tissue depots, and skeletal muscles investigated. The results indicate that cold exposure induces an insulin-like effect on K i that does not appear to be specifically associated with shivering thermogenesis in skeletal muscles, because that effect was observed in all insulin-sensitive tissues. The data also demonstrate that cold exposure significantly potentiates the maximal insulin responses for glucose uptake in the same tissues. This potentialization may result from (1) an enhanced responsiveness of peripheral tissues to insulin, possibly occurring at metabolic steps lying beyond the insulin receptor and (2) an increased tissue blood flow augmenting glucose and insulin availability and thereby amplifying glucose uptake

Thyroid transcriptome analysis reveals different adaptive responses to cold environmental conditions between two chicken breeds.

Science.gov (United States)

Xie, Shanshan; Yang, Xukai; Wang, Dehe; Zhu, Feng; Yang, Ning; Hou, Zhuocheng; Ning, Zhonghua

2018-01-01

, and showed higher responsiveness in BS compared with RIR chickens, suggesting greater adaptability of the thyroid in BS chickens. Moreover, 10,053 differential splicing events were revealed among the groups, with RNA splicing and processing, gene expression, transport, and metabolism being the main affected biological processes, identifying a valuable alternative splicing repertoire for the chicken thyroid. A short isoform of TPO (encoding thyroid peroxidase) containing multiple open reading frames was generated in both breeds by skipping exons 4 and 5 in the cold environment. These findings provide novel clues for future studies of the molecular mechanisms underlying cold adaptation and/or acclimation in chickens.

Short-term acclimation to warmer temperatures accelerates leaf carbon exchange processes across plant types.

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Smith, Nicholas G; Dukes, Jeffrey S

2017-11-01

While temperature responses of photosynthesis and plant respiration are known to acclimate over time in many species, few studies have been designed to directly compare process-level differences in acclimation capacity among plant types. We assessed short-term (7 day) temperature acclimation of the maximum rate of Rubisco carboxylation (V cmax ), the maximum rate of electron transport (J max ), the maximum rate of phosphoenolpyruvate carboxylase carboxylation (V pmax ), and foliar dark respiration (R d ) in 22 plant species that varied in lifespan (annual and perennial), photosynthetic pathway (C 3 and C 4 ), and climate of origin (tropical and nontropical) grown under fertilized, well-watered conditions. In general, acclimation to warmer temperatures increased the rate of each process. The relative increase in different photosynthetic processes varied by plant type, with C 3 species tending to preferentially accelerate CO 2 -limited photosynthetic processes and respiration and C 4 species tending to preferentially accelerate light-limited photosynthetic processes under warmer conditions. R d acclimation to warmer temperatures caused a reduction in temperature sensitivity that resulted in slower rates at high leaf temperatures. R d acclimation was similar across plant types. These results suggest that temperature acclimation of the biochemical processes that underlie plant carbon exchange is common across different plant types, but that acclimation to warmer temperatures tends to have a relatively greater positive effect on the processes most limiting to carbon assimilation, which differ by plant type. The acclimation responses observed here suggest that warmer conditions should lead to increased rates of carbon assimilation when water and nutrients are not limiting. © 2017 John Wiley & Sons Ltd.

The acclimation of Chlorella to high-level nitrite for potential application in biological NOx removal from industrial flue gases.

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Li, Tianpei; Xu, Gang; Rong, Junfeng; Chen, Hui; He, Chenliu; Giordano, Mario; Wang, Qiang

2016-05-20

Nitrogen oxides (NOx) are the components of fossil flue gas that give rise to the greatest environmental concerns. This study evaluated the ability of the green algae Chlorella to acclimate to high level of NOx and the potential utilization of Chlorella strains in biological NOx removal (DeNOx) from industrial flue gases. Fifteen Chlorella strains were subject to high-level of nitrite (HN, 176.5 mmolL(-1) nitrite) to simulate exposure to high NOx. These strains were subsequently divided into four groups with respect to their ability to tolerate nitrite (excellent, good, fair, and poor). One strain from each group was selected to evaluate their photosynthetic response to HN condition, and the nitrite adaptability of the four Chlorella strains were further identified by using chlorophyll fluorescence. The outcome of our experiments shows that, although high concentrations of nitrite overall negatively affect growth and photosynthesis of Chlorella strains, the degree of nitrite tolerance is a strain-specific feature. Some Chlorella strains have an appreciably higher ability to acclimate to high-level of nitrite. Acclimation is achieved through a three-step process of restrict, acclimate, and thriving. Notably, Chlorella sp. C2 was found to have a high tolerance and to rapidly acclimate to high concentrations of nitrite; it is therefore a promising candidate for microalgae-based biological NOx removal. Copyright © 2016 Elsevier GmbH. All rights reserved.

The Rate of Seasonal Changes in Temperature Alters Acclimation of Performance under Climate Change.

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Nilsson-Örtman, Viktor; Johansson, Frank

2017-12-01

How the ability to acclimate will impact individual performance and ecological interactions under climate change remains poorly understood. Theory predicts that the benefit an organism can gain from acclimating depends on the rate at which temperatures change relative to the time it takes to induce beneficial acclimation. Here, we present a conceptual model showing how slower seasonal changes under climate change can alter species' relative performance when they differ in acclimation rate and magnitude. To test predictions from theory, we performed a microcosm experiment where we reared a mid- and a high-latitude damselfly species alone or together under the rapid seasonality currently experienced at 62°N and the slower seasonality predicted for this latitude under climate change and measured larval growth and survival. To separate acclimation effects from fixed thermal responses, we simulated growth trajectories based on species' growth rates at constant temperatures and quantified how much and how fast species needed to acclimate to match the observed growth trajectories. Consistent with our predictions, the results showed that the midlatitude species had a greater capacity for acclimation than the high-latitude species. Furthermore, since acclimation occurred at a slower rate than seasonal temperature changes, the midlatitude species had a small growth advantage over the high-latitude species under the current seasonality but a greater growth advantage under the slower seasonality predicted for this latitude under climate change. In addition, the two species did not differ in survival under the current seasonality, but the midlatitude species had higher survival under the predicted climate change scenario, possibly because rates of cannibalism were lower when smaller heterospecifics were present. These findings highlight the need to incorporate acclimation rates in ecological models.

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 H 2 /L CSFE) was higher than that pre-acclimated with acetate (4.22±0.19L H 2 /L CSFE) and CSFE (4.55±0.14L H 2 /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.

Possible biphasic sweating response during short-term heat acclimation protocol for tropical natives.

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Magalhães, Flávio de Castro; Machado-Moreira, Christiano Antônio; Vimieiro-Gomes, Ana Carolina; Silami-Garcia, Emerson; Lima, Nilo Resende Viana; Rodrigues, Luiz Oswaldo Carneiro

2006-05-01

The aim of the present study was to evaluate the sweat loss response during short-term heat acclimation in tropical natives. Six healthy young male subjects, inhabitants of a tropical region, were heat acclimated by means of nine days of one-hour heat-exercise treatments (40+/-0 degrees C and 32+/-1% relative humidity; 50% (.)VO(2peak) on a cycle ergometer). On days 1 to 9 of heat acclimation whole-body sweat loss was calculated by body weight variation corrected for body surface area. On days 1 and 9 rectal temperature (T(re)) and heart rate (HR) were measured continuously, and rating of perceived exertion (RPE) every 4 minutes. Heat acclimation was confirmed by reduced HR (day 1 rest: 77+/-5 b.min(-1); day 9 rest: 68+/-3 b.min(-1); day 1 final exercise: 161+/-15 b.min(-1); day 9 final exercise: 145+/-11 b.min(-1), p0.05) of the protocol. These findings are consistent with the heat acclimation induced adaptations and suggest a biphasic sweat response (an increase in the sweat rate in the middle of the protocol followed by return to initial values by the end of it) during short-term heat acclimation in tropical natives.

Acclimation of Saccharomyces cerevisiae to low temperature: a chemostat-based transcriptome analysis.

Science.gov (United States)

Tai, Siew Leng; Daran-Lapujade, Pascale; Walsh, Michael C; Pronk, Jack T; Daran, Jean-Marc

2007-12-01

Effects of suboptimal temperatures on transcriptional regulation in yeast have been extensively studied in batch cultures. To eliminate indirect effects of specific growth rates that are inherent to batch-cultivation studies, genome-wide transcriptional responses to low temperatures were analyzed in steady-state chemostats, grown at a fixed specific growth rate (0.03 h(-1)). Although in vivo metabolic fluxes were essentially the same in cultures grown at 12 and at 30 degrees C, concentrations of the growth-limiting nutrients (glucose or ammonia) were higher at 12 degrees C. This difference was reflected by transcript levels of genes that encode transporters for the growth-limiting nutrients. Several transcriptional responses to low temperature occurred under both nutrient-limitation regimes. Increased transcription of ribosome-biogenesis genes emphasized the importance of adapting protein-synthesis capacity to low temperature. In contrast to observations in cold-shock and batch-culture studies, transcript levels of environmental stress response genes were reduced at 12 degrees C. Transcription of trehalose-biosynthesis genes and intracellular trehalose levels indicated that, in contrast to its role in cold-shock adaptation, trehalose is not involved in steady-state low-temperature adaptation. Comparison of the chemostat-based transcriptome data with literature data revealed large differences between transcriptional reprogramming during long-term low-temperature acclimation and the transcriptional responses to a rapid transition to low temperature.

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

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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.

Similarities in temperature-dependent gene expression plasticity across timescales in threespine stickleback (Gasterosteus aculeatus).

Science.gov (United States)

Metzger, David C H; Schulte, Patricia M

2018-04-14

Phenotypic plasticity occurs at a variety of timescales, but little is known about the degree to which plastic responses at different timescales are associated with similar underlying molecular processes, which is critical for assessing the effects of plasticity on evolutionary trajectories. To address this issue, we identified differential gene expression in response to developmental temperature in the muscle transcriptome of adult threespine stickleback (Gasterosteus aculeatus) exposed to 12, 18 and 24°C until hatch and then held at 18°C for 9 months and compared these results to differential gene expression in response to adult thermal acclimation in stickleback developed at 18°C and then acclimated to 5 and 25°C as adults. Adult thermal acclimation affected the expression of 7,940 and 7,015 genes in response to cold and warm acclimation, respectively, and 4,851 of these genes responded in both treatments. In contrast, the expression of only 33 and 29 genes was affected by cold and warm development, respectively. The majority of the genes affected by developmental temperature were also affected by adult acclimation temperature. Many genes that were differentially expressed as a result of adult acclimation were associated with previously identified temperature-dependent effects on DNA methylation patterns, suggesting a role of epigenetic mechanisms in regulating gene expression plasticity during acclimation. Taken together, these results demonstrate similarities between the persistent effects of developmental plasticity on gene expression and the effects of adult thermal acclimation, emphasizing the potential for mechanistic links between plasticity acting at these different life stages. © 2018 John Wiley & Sons Ltd.

Understanding and quantifying foliar temperature acclimation for Earth System Models

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Smith, N. G.; Dukes, J.

2015-12-01

Photosynthesis and respiration on land are the two largest carbon fluxes between the atmosphere and Earth's surface. The parameterization of these processes represent major uncertainties in the terrestrial component of the Earth System Models used to project future climate change. Research has shown that much of this uncertainty is due to the parameterization of the temperature responses of leaf photosynthesis and autotrophic respiration, which are typically based on short-term empirical responses. Here, we show that including longer-term responses to temperature, such as temperature acclimation, can help to reduce this uncertainty and improve model performance, leading to drastic changes in future land-atmosphere carbon feedbacks across multiple models. However, these acclimation formulations have many flaws, including an underrepresentation of many important global flora. In addition, these parameterizations were done using multiple studies that employed differing methodology. As such, we used a consistent methodology to quantify the short- and long-term temperature responses of maximum Rubisco carboxylation (Vcmax), maximum rate of Ribulos-1,5-bisphosphate regeneration (Jmax), and dark respiration (Rd) in multiple species representing each of the plant functional types used in global-scale land surface models. Short-term temperature responses of each process were measured in individuals acclimated for 7 days at one of 5 temperatures (15-35°C). The comparison of short-term curves in plants acclimated to different temperatures were used to evaluate long-term responses. Our analyses indicated that the instantaneous response of each parameter was highly sensitive to the temperature at which they were acclimated. However, we found that this sensitivity was larger in species whose leaves typically experience a greater range of temperatures over the course of their lifespan. These data indicate that models using previous acclimation formulations are likely incorrectly

Acclimation of Chlamydomonas reinhardtii to ultraviolet radiation and its impact on chemical toxicity

Energy Technology Data Exchange (ETDEWEB)

Korkaric, Muris; Xiao, Mao [Eawag, Swiss Federal Institute of Aquatic Science and Technology, Department of Environmental Toxicology, 8600 Duebendorf (Switzerland); ETH Zürich, Institute of Biogeochemistry and Pollutant Dynamics, 8092 Zürich (Switzerland); Behra, Renata [Eawag, Swiss Federal Institute of Aquatic Science and Technology, Department of Environmental Toxicology, 8600 Duebendorf (Switzerland); Eggen, Rik I.L., E-mail: rik.eggen@eawag.ch [Eawag, Swiss Federal Institute of Aquatic Science and Technology, Department of Environmental Toxicology, 8600 Duebendorf (Switzerland); ETH Zürich, Institute of Biogeochemistry and Pollutant Dynamics, 8092 Zürich (Switzerland)

2015-10-15

Highlights: • Systematic study of UVR acclimation and its impact on chemical toxicity in C. reinhardtii. • UVR acclimation is mediated through fast and reversible physiological defense mechanisms. • Pigment analysis suggests a role of lutein in UVR acclimation. • Co-tolerance to rose bengal suggests a role of singlet oxygen defense in UVR acclimation. • Knowledge on the toxic mechanism of chemicals needed to predict co-tolerance. - Abstract: The toxicity of chemical pollutants can be modulated under stressful environmental conditions, such as increased temperature, salinity or ultraviolet radiation (UVR), due to the interaction of effects during simultaneous stressor exposure. However, organisms may acclimate to such conditions by activation of physiological and biochemical defence mechanisms. In sequential exposures, organisms acclimated to environmental stressors may display an increased sensitivity or co-tolerance towards chemical pollutants. It has been suggested that co-tolerance might be expected for similarly acting stressors due to common defence mechanisms. To test this for combinations of UVR and chemical stressors, we first acclimatized the model green alga Chlamydomonas reinhardtii to UVR and subsequently compared the sensitivity of UVR pre-exposed and control algae towards chemicals. Selected chemicals all act on photosynthesis and thus share a common physiological target, but display distinct toxicity mechanisms. Results showed that UVR pre-exposure for four days partially inhibited algal growth and photosynthesis, but also increased algal tolerance to higher UVR levels, confirming UVR acclimation. HPLC analysis of algal pigments indicated that UVR acclimation might in part be explained by the protective function of lutein while the contribution of UVR absorbing compounds was less clear. Challenge exposure to chemicals in the absence of UVR showed that acclimated algae were co-tolerant to the photosensitizer rose bengal, but not to the

Acclimation of Chlamydomonas reinhardtii to ultraviolet radiation and its impact on chemical toxicity

International Nuclear Information System (INIS)

Korkaric, Muris; Xiao, Mao; Behra, Renata; Eggen, Rik I.L.

2015-01-01

Highlights: • Systematic study of UVR acclimation and its impact on chemical toxicity in C. reinhardtii. • UVR acclimation is mediated through fast and reversible physiological defense mechanisms. • Pigment analysis suggests a role of lutein in UVR acclimation. • Co-tolerance to rose bengal suggests a role of singlet oxygen defense in UVR acclimation. • Knowledge on the toxic mechanism of chemicals needed to predict co-tolerance. - Abstract: The toxicity of chemical pollutants can be modulated under stressful environmental conditions, such as increased temperature, salinity or ultraviolet radiation (UVR), due to the interaction of effects during simultaneous stressor exposure. However, organisms may acclimate to such conditions by activation of physiological and biochemical defence mechanisms. In sequential exposures, organisms acclimated to environmental stressors may display an increased sensitivity or co-tolerance towards chemical pollutants. It has been suggested that co-tolerance might be expected for similarly acting stressors due to common defence mechanisms. To test this for combinations of UVR and chemical stressors, we first acclimatized the model green alga Chlamydomonas reinhardtii to UVR and subsequently compared the sensitivity of UVR pre-exposed and control algae towards chemicals. Selected chemicals all act on photosynthesis and thus share a common physiological target, but display distinct toxicity mechanisms. Results showed that UVR pre-exposure for four days partially inhibited algal growth and photosynthesis, but also increased algal tolerance to higher UVR levels, confirming UVR acclimation. HPLC analysis of algal pigments indicated that UVR acclimation might in part be explained by the protective function of lutein while the contribution of UVR absorbing compounds was less clear. Challenge exposure to chemicals in the absence of UVR showed that acclimated algae were co-tolerant to the photosensitizer rose bengal, but not to the

Effects of acclimation on poststocking dispersal and physiological condition of age-1 pallid sturgeon

Science.gov (United States)

Oldenburg, E.W.; Guy, C.S.; Cureton, E.S.; Webb, M.A.H.; Gardner, W.M.

2011-01-01

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 hatchery-reared 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 controls had no acclimation (reared under traditional conservation propagation 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 as compared to control fish. In 2006, pallid sturgeon dispersed similarly among treatments and the number of fish remaining in the Missouri River reach was similar among all treatments. Differences in poststocking dispersal between years were related to fin curl which was present in all fish in 2005 and only 26% 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, release site influenced poststocking dispersal more than acclimation treatment. No difference was observed in relative growth rate among treatments. However, acclimation to flow (i.e., exercise conditioning) prevented fat accumulation from rupturing hepatocytes. Acclimation conditions used in this study did not benefit pallid sturgeon unless physiological maladies were present. Overriding all treatment effects was stocking location; thus, natural resource agencies need to consider stocking location carefully to reduce poststocking dispersal. ?? 2011 Blackwell Verlag, Berlin.

No effects of acclimation to heat on immune and hormonal responses to passive heating in healthy volunteers

Science.gov (United States)

Kanikowska, Dominika; Sato, Maki; Sugenoya, Junichi; Iwase, Satoshi; Shimizu, Yuuki; Nishimura, Naoki; Inukai, Yoko

2012-01-01

Heat acclimation results in whole body-adaptations that increase heat tolerance, and might also result in changed immune responses. We hypothesized that, after heat acclimation, tumor necrosis factor alpha, interleukin 6 and the lymphocyte count would be altered. Heat acclimation was induced in 6 healthy men by 100 min of heat exposure for 9 days. Heat exposure consisted of (1) 10 min of immersion up to chest-level in water at 42°C and (2) 90 min of passive heating by a warm blanket to maintain tympanic temperature at 37.5°C. The climatic chamber was maintained at 40°C and a relative humidity of 50%. Blood samples were analyzed before and after heat acclimation for natural killer (NK) cell activity, counts of lymphocytes B and T, before and after heat acclimation for peripheral blood morphology, interleukin 6, tumor necrosis factor alpha, and cortisol. A Japanese version of the profile of mood states questionnaire was also administered before and after acclimation. The concentrations of white blood cells, lymphocytes B and T, cortisol, interleukin 6, tumor necrosis factor alpha and NK cell activity showed no significant differences between pre- and post-acclimation, but there was a significantly lower platelet count after acclimation and, with the profile of mood states questionnaire, there was a significant rise in anger after acclimation. It is concluded that heat acclimation by passive heating does not induce alterations in immune or endocrine responses.

Transgenerational acclimation of fishes to climate change and ocean acidification

OpenAIRE

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...

Dicty_cDB: SSL481 [Dicty_cDB

Lifescience Database Archive (English)

Full Text Available 1442.1 UCRCS01_02dg03_g1 Washington Navel orange cold acclimated flavedo & albedo cDNA library Citrus sinens...is cDNA clone UCRCS01_02dg03, mRNA sequence. 42 5.2 1 CB293485 |CB293485.1 UCRCS01_06ag01_g1 Washington Navel orange cold acclimate... UCRCS01_06ag01, mRNA sequence. 42 5.2 1 CB293416 |CB293416.1 UCRCS01_06ac11_b1 Washington Navel orange cold acclimate... CB291577 |CB291577.1 UCRCS01_03af02_g1 Washington Navel orange cold acclimated f

Differential metabolic rearrangements after cold storage are correlated with chilling injury resistance of peach fruits

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Claudia A Bustamante

2016-09-01

Full Text Available Reconfiguration of the metabolome is a key component involved in the acclimation to cold in plants; however, few studies have been devoted to the analysis of the overall metabolite changes after cold storage of fruits prior to consumption. Here, metabolite profiling of six peach varieties with differential susceptibility to develop mealiness, a chilling-injury (CI symptom, was performed. According to metabolic content at harvest; after cold treatment; and after ripening, either following cold treatment or not; peach fruits clustered in distinct groups, depending on harvest-time, cold treatment, and ripening state. Both common and distinct metabolic responses among the six varieties were found; common changes including dramatic galactinol and raffinose rise; GABA, Asp and Phe increase; and 2-oxo-glutarate and succinate decrease. Raffinose content after long cold treatment quantitatively correlated to the degree of mealiness resistance of the different peach varieties; and thus, raffinose emerges as a candidate biomarker of this CI disorder. Xylose increase after cold treatment was found only in the susceptible genotypes, indicating a particular cell wall reconfiguration of these varieties while being cold-stored. Overall, results indicate that peach fruit differential metabolic rearrangements due to cold treatment, rather than differential metabolic priming before cold, are better related with CI resistance. The plasticity of peach fruit metabolism renders it possible to induce a diverse metabolite array after cold, which is successful, in some genotypes, to avoid CI

Alleviation of cold damage to photosystem II and metabolisms by melatonin in Bermudagrass

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Jibiao eFan

2015-11-01

Full Text Available As a typical warm-season grass, Bermudagrass [Cynodon dactylon (L.Pers.] is widely applied in turf systems and animal husbandry. However, cold temperature is a key factor limiting resource utilization for Bermudagrass. Therefore, it is relevant to study the mechanisms by which Burmudagrass responds to cold. Melatonin is a crucial animal and plant hormone that is responsible for plant abiotic stress responses. The objective of this study was to investigate the role of melatonin in cold stress response of Bermudagrass. Wild Bermudagrass pre-treated with 100 μM melatonin was subjected to different cold stress treatments (-5 °C for 8 h with or without cold acclimation. The results showed lower malondialdehyde (MDA and electrolyte leakage (EL values, higher levels of chlorophyll, and greater superoxide dismutase and peroxidase activities after melatonin treatment than those in non-melatonin treatment under cold stress. Analysis of chlorophyll a revealed that the chlorophyll fluorescence transient (OJIP curves were higher after treatment with melatonin than that of non-melatonin treated plants under cold stress. The values of photosynthetic fluorescence parameters increased after treatment with melatonin under cold stress. The analysis of metabolism showed alterations in 46 metabolites in cold-stressed plants after melatonin treatment. Among the measured metabolites, five sugars (arabinose, mannose, glucopyranose, maltose, turanose and one organic acid (propanoic acid were significantly increased. However, valine and threonic acid contents were reduced in melatonin-treated plants. In summary, melatonin maintained cell membrane stability, increased antioxidant enzymes activities, improved the process of photosystem II, and induced alterations in Bermudagrass metabolism under cold stress.

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.

Cold hardiness research on agricultural and horticultural crops in Finland

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L. LINDÉN

2008-12-01

Full Text Available This paper represents an overview of cold hardiness research conducted on agricultural and horticultural crops, as well as on amenity plants in Finland. Inadequate freezing tolerance and/or winter hardiness often prevents introduction of new species and cultivars to Finland. Field observations on winter hardiness and more recently the results from laboratory freezing tests, have assisted breeders to select hardy genotypes. Research approaches for agricultural crops have evolved from observations on winter and frost damage to studies on molecular mechanisms of cold acclimation and freezing injury. The results of experiments on survival of winter cereals, grasses and clovers and frost tolerance of potato and turnip rape are discussed. The studies conducted on horticultural crops, including apple, strawberry, raspberry, currants, blueberry, sea buckthorn, perennial herbs as well as on ornamental trees and shrubs have included field evaluations of cultivars, or selections for winter hardiness, and studies on the effects of cultural management practices on winter survival. During the last decade detailed studies including controlled freezing tests have provided tools to assist in explanation of the underlying mechanisms of cold hardiness also in horticultural plants. ;

Temperature selection of goldfish (Carassius auratus L. ) and brook trout (Salvelinus fontinalis Mitch. ) after heterogeneous temperature acclimation

Energy Technology Data Exchange (ETDEWEB)

Mueller, R.

1977-01-01

Goldfish and brook trout were acclimated heterogeneously to temperature by exposing the head and tail simultaneously to different temperatures. The temperature selection of heterogeneously acclimated fish was tested in a vertical temperature gradient and compared to that of homogeneously acclimated fish. All fish selected temperatures essentially corresponding to the state of acclimation of their head. It is concluded that the brain acts as the main control of temperature selection in fish.

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

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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.

The effects of fasting and cold exposure on metabolic rate and mitochondrial proton leak in liver and skeletal muscle of an amphibian, the cane toad Bufo marinus.

Science.gov (United States)

Trzcionka, M; Withers, K W; Klingenspor, M; Jastroch, M

2008-06-01

Futile cycling of protons across the mitochondrial inner membrane contributes significantly to standard metabolic rate in a variety of ectothermic and endothermic animals, but adaptations of the mitochondrial bioenergetics to different environmental conditions have rarely been studied in ectotherms. Changes in ambient temperature and nutritional status have a great effect on the physiological demands of ectothermic amphibians and may require the adjustment of mitochondrial efficiency. In order to investigate the effect of temperature and nutritional status on the mitochondrial level, we exposed male cane toads to either 10 degrees C or 30 degrees C and fasted half of the animals in each group. Cold exposure resulted in a fourfold reduction of the resting metabolic rate whereas nutritional status had only minor effects. The mitochondrial adjustments to each condition were observed by comparing the proton leak kinetics of isolated liver and skeletal muscle mitochondria at 25 degrees C. In response to cold exposure, liver mitochondria showed a decrease in proton conductance while skeletal muscle mitochondria were unchanged. Additional food deprivation had minor effects in skeletal muscle, but in liver we uncovered surprising differences in energy saving mechanisms between the acclimation temperatures: in warm-acclimated toads, fasting resulted in a decrease of the proton conductance whereas in cold-acclimated toads, the activity of the respiratory chain was reduced. To investigate the molecular mechanism underlying mitochondrial proton leakage, we determined the adenine-nucleotide transporter (ANT) content, which explained tissue-specific differences in the basal proton leak, but neither the ANT nor uncoupling protein (UCP) gene expression correlated with alterations of the proton leak in response to physiological stimuli.

Dynamic reorganization of photosynthetic supercomplexes during environmental acclimation

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Jun eMinagawa

2013-12-01

Full Text Available Plants and algae have acquired the ability to acclimate to ever-changing environments in order to survive. During photosynthesis, light energy is converted by several membrane protein supercomplexes into electrochemical energy, which is eventually used to assimilate CO2. The efficiency of photosynthesis is modulated by many environmental factors such as quality and quantity of light, temperature, drought, and CO2 concentration, among others. Accumulating evidence indicates that photosynthetic supercomplexes undergo supramolecular reorganization within a short timeframe during acclimation to an environmental change. This reorganization includes state transitions that balance the excitation of photosystem I and II by shuttling peripheral antenna proteins between the two, thermal energy dissipation that occurs at energy-quenching sites within the light-harvesting antenna generated for negative feedback when excess light is absorbed, and cyclic electron flow that is facilitated between photosystem I and the cytochrome bf complex when cells demand more ATP and/or need to activate energy dissipation. This review will highlight the recent findings regarding these environmental acclimation events in model organisms with particular attention to the unicellular green alga C. reinhardtii and with reference to the vascular plant A. thaliana, which offers a glimpse into the dynamic behavior of photosynthetic machineries in nature.

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.

A Novel Protocol to Assess Acclimation Rate in Bos taurus Heifers during Yard Weaning

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Jessica E. Monk

2018-04-01

Full Text Available The speed with which animals acclimate to a new environment could be an important measure of ability to cope with management induced stress. This study developed a measure of acclimation rate in a group of 50 Bos taurus heifers during yard weaning over nine days. We recorded the time and order in which heifers moved through a novel funnel structure into a feeding yard daily. We hypothesised that addition of an obstacle at the entrance would increase the time it took heifers to move through the funnel, but that they would acclimate to the obstacle over a three-day period. The change in latency to move through could then be used as a measure of acclimation rate. We hypothesised that individuals which acclimated to obstacles at a faster rate might display favourable temperament as assessed by flight time. All heifers took longer to move through the funnel after a novel object was introduced, then latency decreased over the following two days while the object was present. This indicates the protocol could be useful for measuring acclimation rate at a group level. Individual acclimation rate variables, measured as change in times and orders of heifers between test days, did not appear to have any consistent relationships with flight time or weight change during or post-weaning (p > 0.05. We concluded that the protocol was inappropriate for assessing acclimation rate at an individual level, due to social effects while testing heifers as a group. Heifers which were consistently one of the first 20 to move through the funnel had a significantly greater average weight 5 and 10 months post-weaning (345 ± 9 kg and 518 ± 10 kg respectively than heifers which were consistently one of the last 20 through the funnel (311 ± 8 kg and 484 ± 8 kg respectively; p < 0.001. This may indicate order of movement through the funnel was related to feeding motivation or another aspect of temperament not reflected by flight time.

Complex phytohormone responses during the cold acclimation of two wheat cultivars differing in cold tolerance, winter Samanta and spring Sandra

Czech Academy of Sciences Publication Activity Database

Kosová, K.; Prášil, I.T.; Vítámvás, P.; Dobrev, Petre; Motyka, Václav; Floková, Kristýna; Novák, Ondřej; Turečková, Veronika; Rolčík, Jakub; Pešek, Bedřich; Trávníčková, Alena; Gaudinová, Alena; Galiba, G.; Janda, T.; Vlasáková, E.; Prášilová, P.; Vaňková, Radomíra

2012-01-01

Roč. 169, č. 6 (2012), s. 567-576 ISSN 0176-1617 R&D Projects: GA ČR GA522/09/2058; GA MŠk MEB040713; GA MŠk MEB040924 Grant - others:GA ČR(CZ) GPP501/11/P637 Program:GP Institutional research plan: CEZ:AV0Z50380511 Keywords : Cold stress * Dehydrin * Frost tolerance Subject RIV: ED - Physiology Impact factor: 2.699, year: 2012

Salt acclimation process: a comparison between a sensitive and a tolerant Olea europaea cultivar.

Science.gov (United States)

Pandolfi, Camilla; Bazihizina, Nadia; Giordano, Cristiana; Mancuso, Stefano; Azzarello, Elisa

2017-03-01

Saline soils are highly heterogeneous in time and space, and this is a critical factor influencing plant physiology and productivity. Temporal changes in soil salinity can alter plant responses to salinity, and pre-treating plants with low NaCl concentrations has been found to substantially increase salt tolerance in different species in a process called acclimation. However, it still remains unclear whether this process is common to all plants or is only expressed in certain genotypes. We addressed this question by assessing the physiological changes to 100 mM NaCl in two contrasting olive cultivars (the salt-sensitive Leccino and the salt-tolerant Frantoio), following a 1-month acclimation period with 5 or 25 mM NaCl. The acclimation improved salt tolerance in both cultivars, but activated substantially different physiological adjustments in the tolerant and the sensitive cultivars. In the tolerant Frantoio the acclimation with 5 mM NaCl was more effective in increasing plant salt tolerance, with a 47% increase in total plant dry mass compared with non-acclimated saline plants. This enhanced biomass accumulation was associated with a 50% increase in K+ retention ability in roots. On the other hand, in the sensitive Leccino, although the acclimation process did not improve performance in terms of plant growth, pre-treatment with 5 and 25 mM NaCl substantially decreased salt-induced leaf cell ultrastructural changes, with leaf cell relatively similar to those of control plants. Taken together these results suggest that in the tolerant cultivar the acclimation took place primarily in the root tissues, while in the sensitive they occurred mainly at the shoot level. © The Author 2017. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

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

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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.

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

International Nuclear Information System (INIS)

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

2016-01-01

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.

Conserved TRAM Domain Functions as an Archaeal Cold Shock Protein via RNA Chaperone Activity

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Bo Zhang

2017-08-01

Full Text Available Cold shock proteins (Csps enable organisms to acclimate to and survive in cold environments and the bacterial CspA family exerts the cold protection via its RNA chaperone activity. However, most Archaea do not contain orthologs to the bacterial csp. TRAM, a conserved domain among RNA modification proteins ubiquitously distributed in organisms, occurs as an individual protein in most archaeal phyla and has a structural similarity to Csp proteins, yet its biological functions remain unknown. Through physiological and biochemical studies on four TRAM proteins from a cold adaptive archaeon Methanolobus psychrophilus R15, this work demonstrated that TRAM is an archaeal Csp and exhibits RNA chaperone activity. Three TRAM encoding genes (Mpsy_0643, Mpsy_3043, and Mpsy_3066 exhibited remarkable cold-shock induced transcription and were preferentially translated at lower temperature (18°C, while the fourth (Mpsy_2002 was constitutively expressed. They were all able to complement the cspABGE mutant of Escherichia coli BX04 that does not grow in cold temperatures and showed transcriptional antitermination. TRAM3066 (gene product of Mpsy_3066 and TRAM2002 (gene product of Mpsy_2002 displayed sequence-non-specific RNA but not DNA binding activity, and TRAM3066 assisted RNases in degradation of structured RNA, thus validating the RNA chaperone activity of TRAMs. Given the chaperone activity, TRAM is predicted to function beyond a Csp.

Acclimation and tolerance of Artemia salina to copper salts

Energy Technology Data Exchange (ETDEWEB)

Saliba, L.J.; Krzyz, R.M.

1976-01-01

The brine shrimp Artemia salina L. was acclimated in sea water with cupric chloride, acetate, carbonate, and sulfate, each at concentrations of 0.1, 0.05 and 0.025 ppM Cu/sup + +/, together with sea water controls. Growth inhibition was observed in all four compounds, generally in direct relationship to the concentration. It was least in sulfate, and increased progressively in chloride, acetate and carbonate in that order. In toxicity tests, 2-week old larvae from each solution were exposed to concentrations of 10, 7.5, 5, 2.5 and 1 ppM Cu/sup + +/ of the same compounds, together with unacclimated larvae of the same age. Similar tests were held with 6-week old adults. Toxicity to unacclimated larvae and adults differed with the compounds, carbonate being the least toxic, followed by sulfate, chloride and acetate in increasing order. Larvae acclimated in chloride and sulfate showed an increased tolerance to 1 and 2.5 ppM Cu/sup + +/ compared to untreated controls. Tolerance was not enhanced from 5 ppM Cu/sup + +/ upwards. In both compounds, adults acclimated in 0.1 ppM Cu/sup + +/ showed an increased tolerance to concentrations between 1 and 7.5 ppM Cu/sup + +/ compared to controls. Considerable precipitation occurred with the high levels of this compound, thus effecting the ''final'' concentrations. No acclimation effect was observed in acetate for either larvae or adults. It is suggested that in A. salina, copper toxicity depends on the particular form of the metal, and that this difference is also evident in growth inhibition and in the potential acquisition of increased tolerance through exposure to low concentrations.

Photosynthetic acclimation of WS and WS-gpt2 in Arabidopsis thaliana under fluctuating natural light condition

Science.gov (United States)

Pa'ee, Furzani; Johnson, Giles

2017-10-01

Photoacclimation is a process by which photosynthetic capacity is regulated in response to environmental adjustments in terms of light regime. Photoacclimation is essential in determining the photosynthetic capacity to optimize light use and to avoid potentially damaging effects. Previous work in our laboratory has identified a gene, gpt2 (At1g61800) that is essential for plants to acclimate to an increase and decrease of growth irradiance, separately. To investigate the photoacclimation ability towards fluctuating natural light condition in Arabidopsis thaliana, photosynthetic capacity was measured in plants of the accession Wassileskija (WS) and in plants lacking expression of the gene At1g61800 (WS-gpt2). The experiment was carried out over a time span from early Autumn to early Spring season in 2010-2011 and 2011-2012. The seedlings were grown in an unheated greenhouse in Manchester, UK without supplementary lighting. Gas exchange measurements and chlorophyll content estimation were performed on WS and WS-gpt2 and it showed that both sets of plants were able to acclimate to fluctuating natural light condition. Therefore, it is suggested that the mechanisms of acclimation in a separate growth light condition is mechanistically distinct than the mechanism under fluctuating natural light condition.

Arabidopsis dynamin-related protein 1E in sphingolipid-enriched plasma membrane domains is associated with the development of freezing tolerance.

Science.gov (United States)

Minami, Anzu; Tominaga, Yoko; Furuto, Akari; Kondo, Mariko; Kawamura, Yukio; Uemura, Matsuo

2015-08-01

The freezing tolerance of Arabidopsis thaliana is enhanced by cold acclimation, resulting in changes in the compositions and function of the plasma membrane. Here, we show that a dynamin-related protein 1E (DRP1E), which is thought to function in the vesicle trafficking pathway in cells, is related to an increase in freezing tolerance during cold acclimation. DRP1E accumulated in sphingolipid and sterol-enriched plasma membrane domains after cold acclimation. Analysis of drp1e mutants clearly showed that DRP1E is required for full development of freezing tolerance after cold acclimation. DRP1E fused with green fluorescent protein was visible as small foci that overlapped with fluorescent dye-labelled plasma membrane, providing evidence that DRP1E localizes non-uniformly in specific areas of the plasma membrane. These results suggest that DRP1E accumulates in sphingolipid and sterol-enriched plasma membrane domains and plays a role in freezing tolerance development during cold acclimation. © 2015 The Authors The Plant Journal © 2015 John Wiley & Sons Ltd.

Heat Acclimation-Mediated Cross-Tolerance: Origins in within-Life Epigenetics?

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Michal Horowitz

2017-07-01

Full Text Available The primary outcome of heat acclimation is increased thermotolerance, which stems from enhancement of innate cytoprotective pathways. These pathways produce “ON CALL” molecules that can combat stressors to which the body has never been exposed, via cross-tolerance mechanisms (heat acclimation-mediated cross-tolerance—HACT. The foundation of HACT lies in the sharing of generic stress signaling, combined with tissue/organ- specific protective responses. HACT becomes apparent when acclimatory homeostasis is achieved, lasts for several weeks, and has a memory. HACT differs from other forms of temporal protective mechanisms activated by exposure to lower “doses” of the stressor, which induce adaptation to higher “doses” of the same/different stressor; e.g., preconditioning, hormesis. These terms have been adopted by biochemists, toxicologists, and physiologists to describe the rapid cellular strategies ensuring homeostasis. HACT employs two major protective avenues: constitutive injury attenuation and abrupt post-insult release of help signals enhanced by acclimation. To date, the injury-attenuating features seen in all organs studied include fast-responding, enlarged cytoprotective reserves with HSPs, anti-oxidative, anti-apoptotic molecules, and HIF-1α nuclear and mitochondrial target gene products. Using cardiac ischemia and brain hypoxia models as a guide to the broader framework of phenotypic plasticity, HACT is enabled by a metabolic shift induced by HIF-1α and there are less injuries caused by Ca+2 overload, via channel or complex-protein remodeling, or decreased channel abundance. Epigenetic markers such as post-translational histone modification and altered levels of chromatin modifiers during acclimation and its decline suggest that dynamic epigenetic mechanisms controlling gene expression induce HACT and acclimation memory, to enable the rapid return of the protected phenotype. In this review the link between in vivo

Gastrointestinal uptake and fate of cadmium in rainbow trout acclimated to sublethal dietary cadmium

International Nuclear Information System (INIS)

Chowdhury, M.J.; McDonald, D.G.; Wood, C.M.

2004-01-01

Adult rainbow trout were pre-exposed to a sublethal concentration of dietary Cd (500 mg/kg dry wt.) for 30 days to induce acclimation. A gastrointestinal dose of radiolabeled Cd (276 μg/kg wet wt.) was infused into the stomach of non-acclimated and Cd-acclimated trout through a stomach catheter. Repetitive blood samples over 24 h and terminal tissue samples were taken to investigate the gastrointestinal uptake, plasma clearance kinetics, and tissue distribution of Cd. Only a small fraction of the infused dose (non-acclimated: 2.4%; Cd-acclimated: 6.6%) was internalized across the gut wall, while most was bound in the gut tissues (10-24%) or remained in the lumen (16-33%) or lost from the fish (∼50%) over 24 h. Cadmium loading during pre-exposure produced a profound increase of total Cd in the blood plasma (∼28-fold) and red blood cells (RBC; ∼20-fold). The plasma Cd-time profiles consisted of an apparent rising (uptake) phase and a declining (clearance) phase with a maximum value of uptake in 4 h, suggesting that uptake of gastrointestinally infused Cd was very rapid. Acclimation to dietary Cd did not affect plasma Cd clearance (∼0.5 ml/min), but enhanced new Cd levels in the plasma (but not in the RBC), and resulted in a longer half-life for plasma Cd. Tissue total and new Cd levels varied in different regions of the gastrointestinal tract, and overall levels in gut tissues were much greater than in non-gut tissues, reflecting the Cd exposure route. Dietary Cd, but not the infused Cd, greatly increased total Cd levels of all gut tissues in the order posterior-intestine (640-fold) > cecae (180-fold) > mid-intestine (94-fold) > stomach (53-fold) in Cd-acclimated fish relative to naieve fish. Among non-gut tissues in the Cd-acclimated fish, the great increases of total Cd levels were observed in the liver (73-fold), kidney (39-fold), carcass (35-fold), and gills (30-fold). The results provide some clear conclusions that may be useful for environmental risk

Integrative omic analysis reveals distinctive cold responses in leaves and roots of strawberry, Fragaria × ananassa ‘Korona’

Directory of Open Access Journals (Sweden)

Gage eKoehler

2015-10-01

Full Text Available To assess underlying metabolic processes and regulatory mechanisms during cold exposure of strawberry, integrative omic approaches were applied to Fragaria × ananassa Duch. ‘Korona’. Both root and leaf tissues were examined for responses to the cold acclimation processes. Levels of metabolites, proteins, and transcripts in tissues from plants grown at 18°C were compared to those following 1 to 10 days of cold (2°C exposure. Overall, ‘Korona’ showed a modest increase of protective metabolites such as amino acids (aspartic acid, leucine, isoleucine, and valine, pentoses, phosphorylated and non-phosphorylated hexoses, and distinct compounds of the raffinose pathway (galactinol and raffinose. By 2DE proteomics a total of 845 spots were observed in leaves; 4.6% changed significantly in response to cold.Transcript levels in leaves were determined by microarray, where dozens of cold associated transcripts were quantitatively characterized, and levels of several potential key contributors (e.g., the dehydrin COR47 and GADb to cold tolerance were confirmed by qRT-PCR. Cold responses are placed within the existing knowledge base of low temperature stress change in plants, allowing an evaluation of the uniqueness or generality of Fragaria responses in photosynthetic tissues. Overall, the cold response characteristics of ‘Korona’ are consistent with a moderately cold tolerant plant.

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.

Acclimation to and recovery from cadmium and zinc exposure by a freshwater cyanobacterium, Microcystis aeruginosa

International Nuclear Information System (INIS)

Zeng Jin; Yang Liuyan; Wang Wenxiong

2009-01-01

To understand the metal tolerance of a bloom-forming cyanobacterium, Microcystis aeruginosa, we investigated its acclimation to and recovery from cadmium (Cd) and zinc (Zn) exposure. The intracellular Cd and Zn (intra-Cd and intra-Zn) quotas increased upon acclimation to increased metal concentrations and were reduced following 1-day or 5-day recovery. Different acclimation to varying metal concentrations or durations (5 days or 15 days) did not have significant effects on the short-term uptake of Cd or Zn, whereas a 1-day recovery period promoted Cd or Zn uptake significantly. The values of median growth-inhibition concentrations (free ion concentration or intracellular quota) increased when the cyanobacterial cells were acclimated to higher Cd or Zn concentrations, indicating that M. aeruginosa became more tolerant to these metals. Consistent with the significant increase in metal uptake, the cyanobacteria become very sensitive to metals following 1-day recovery. A longer recovery (5 days) led to comparable uptake and toxicity responses to the controls. The efflux rate constants were not significantly different following metal acclimation. In the subcellular metal measurements, Cd was mostly distributed in the soluble fraction, whereas Zn was distributed evenly in the adsorbed, insoluble and soluble fractions of the cells. This study suggested the strong ability of these cyanobacteria to acclimate to different environments.

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...

Mechanisms and fitness implications of photomorphogenesis during chromatic acclimation in cyanobacteria.

Science.gov (United States)

Montgomery, Beronda L

2016-07-01

Photosynthetic organisms absorb photons and convert light energy to chemical energy through the process of photosynthesis. Photosynthetic efficiency is tuned in response to the availability of light, carbon dioxide and nutrients to promote maximal levels of carbon fixation, while simultaneously limiting the potential for light-associated damage or phototoxicity. Given the central dependence on light for energy production, photosynthetic organisms possess abilities to tune their growth, development and metabolism to external light cues in the process of photomorphogenesis. Photosynthetic organisms perceive light intensity and distinct wavelengths or colors of light to promote organismal acclimation. Cyanobacteria are oxygenic photosynthetic prokaryotes that exhibit abilities to alter specific aspects of growth, including photosynthetic pigment composition and morphology, in responses to changes in available wavelengths and intensity of light. This form of photomorphogenesis is known as chromatic acclimation and has been widely studied. Recent insights into the photosensory photoreceptors found in cyanobacteria and developments in our understanding of the molecular mechanisms initiated by light sensing to affect the changes characteristic of chromatic acclimation are discussed. I consider cyanobacterial responses to light, the broad diversity of photoreceptors encoded by these organisms, specific mechanisms of photomorphogenesis, and associated fitness implications in chromatically acclimating cyanobacteria. © The Author 2016. Published by Oxford University Press on behalf of the Society for Experimental Biology. All rights reserved. For permissions, please email: journals.permissions@oup.com.

Higher plant acclimation to solar ultraviolet-B radiation

International Nuclear Information System (INIS)

Robberecht, R.

1981-01-01

The objectives of this study were to determine: (1) the relationship between plant sensitivity and epidermal uv attenuation, (2) the effect of phenotypic changes in the leaf epidermis, resulting from uv-B exposure, on plant sensitivity to uv radiation, and (3) the platicity of these changes in the epidermis leading to plant acclimation to uv-B radiation. A mechanism of uv-B attenuation, possibly involving the biosynthesis of uv-absorbing flavonoid compounds in the epidermis and mesophyll under the stress of uv-B radiation, and a subsequent increase in the uv-B attenuation capacity of the epidermis, is suggested. The degree of plant sensitivity and acclimation to natural and intensified solar uv-B radiation may involve a dynamic balance between the capacity for uv-B attenuation and uv-radiation-repair mechanisms in the leaf

Adaptations and mechanisms of human heat acclimation: Applications for competitive athletes and sports.

Science.gov (United States)

Périard, J D; Racinais, S; Sawka, M N

2015-06-01

Exercise heat acclimation induces physiological adaptations that improve thermoregulation, attenuate physiological strain, reduce the risk of serious heat illness, and improve aerobic performance in warm-hot environments and potentially in temperate environments. The adaptations include improved sweating, improved skin blood flow, lowered body temperatures, reduced cardiovascular strain, improved fluid balance, altered metabolism, and enhanced cellular protection. The magnitudes of adaptations are determined by the intensity, duration, frequency, and number of heat exposures, as well as the environmental conditions (i.e., dry or humid heat). Evidence is emerging that controlled hyperthermia regimens where a target core temperature is maintained, enable more rapid and complete adaptations relative to the traditional constant work rate exercise heat acclimation regimens. Furthermore, inducing heat acclimation outdoors in a natural field setting may provide more specific adaptations based on direct exposure to the exact environmental and exercise conditions to be encountered during competition. This review initially examines the physiological adaptations associated with heat acclimation induction regimens, and subsequently emphasizes their application to competitive athletes and sports. © 2015 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Lipid-induced thermogenesis is up-regulated by the first cold-water immersions in juvenile penguins.

Science.gov (United States)

Teulier, Loïc; Rey, Benjamin; Tornos, Jérémy; Le Coadic, Marion; Monternier, Pierre-Axel; Bourguignon, Aurore; Dolmazon, Virginie; Romestaing, Caroline; Rouanet, Jean-Louis; Duchamp, Claude; Roussel, Damien

2016-07-01

The passage from shore to marine life is a critical step in the development of juvenile penguins and is characterized by a fuel selection towards lipid oxidation concomitant to an enhancement of lipid-induced thermogenesis. However, mechanisms of such thermogenic improvement at fledging remain undefined. We used two different groups of pre-fledging king penguins (Aptenodytes patagonicus) to investigate the specific contribution of cold exposure during water immersion to lipid metabolism. Terrestrial penguins that had never been immersed in cold water were compared with experimentally cold-water immersed juveniles. Experimentally immersed penguins underwent ten successive immersions at approximately 9-10 °C for 5 h over 3 weeks. We evaluated adaptive thermogenesis by measuring body temperature, metabolic rate and shivering activity in fully immersed penguins exposed to water temperatures ranging from 12 to 29 °C. Both never-immersed and experimentally immersed penguins were able to maintain their homeothermy in cold water, exhibiting similar thermogenic activity. In vivo, perfusion of lipid emulsion at thermoneutrality induced a twofold larger calorigenic response in experimentally immersed than in never-immersed birds. In vitro, the respiratory rates and the oxidative phosphorylation efficiency of isolated muscle mitochondria were not improved with cold-water immersions. The present study shows that acclimation to cold water only partially reproduced the fuel selection towards lipid oxidation that characterizes penguin acclimatization to marine life.

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

DEFF Research Database (Denmark)

Staehr, Peter Anton; 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 saturate...... in a future climate scenario, suggested that expected increases in temperature and nutrient run-off have synergistic negative effects, especially in clear waters, stressing the importance of continued efforts to improve water clarity of coastal waters.......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...... a positive carbon balance increased exponentially with increasing temperature but less so for summer-acclimated than for winter-acclimated plants. However, combining EC vs temperature models for whole-plants with data on daily light availability showed that seasonal acclimation in metabolism increased...

Genotype-dependent Burst of Transposable Element Expression in Crowns of Hexaploid Wheat (Triticum aestivum L. during Cold Acclimation

Directory of Open Access Journals (Sweden)

Debbie Laudencia-Chingcuanco

2012-01-01

Full Text Available The expression of 1,613 transposable elements (TEs represented in the Affymetrix Wheat Genome Chip was examined during cold treatment in crowns of four hexaploid wheat genotypes that vary in tolerance to cold and in flowering time. The TE expression profiles showed a constant level of expression throughout the experiment in three of the genotypes. In winter Norstar, the most cold-hardy of the four genotypes, a subset of the TEs showed a burst of expression after vernalization saturation was achieved. About 47% of the TEs were expressed, and both Class I (retrotransposons and Class II (DNA transposons types were well represented. Gypsy and Copia were the most represented among the retrotransposons while CACTA and Mariner were the most represented DNA transposons. The data suggests that the Vrn-A1 region plays a role in the stage-specific induction of TE expression in this genotype.

[Adenosine triphosphatase activity in the organs of the crab Hemigrapsus sanguineus, acclimated to sea water of different salinity].

Science.gov (United States)

Busev, V M

1977-01-01

In crabs acclimated to low salinity, the activity of Na, K-ATPase from the gills increases; the activity also increases in the antennal glands after acclimation of the animals to high salinity. The activity of Na, K-ATPase in the abdominal ganglion and in the heart does not depend on the salinity to which crabs had been acclimated. Changes in the activity of Mg-ATPase in the gills and antennal glands associated with acclimation of crabs to sea water with different salinity correspond to those in the activity of Na, K-ATPase.

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. Copyright © 2016 the American Physiological Society.

De Novo Transcriptome Sequencing in Passiflora edulis Sims to Identify Genes and Signaling Pathways Involved in Cold Tolerance

Directory of Open Access Journals (Sweden)

Sian Liu

2017-11-01

Full Text Available The passion fruit (Passiflora edulis Sims, also known as the purple granadilla, is widely cultivated as the new darling of the fruit market throughout southern China. This exotic and perennial climber is adapted to warm and humid climates, and thus is generally intolerant of cold. There is limited information about gene regulation and signaling pathways related to the cold stress response in this species. In this study, two transcriptome libraries (KEDU_AP vs. GX_AP were constructed from the aerial parts of cold-tolerant and cold-susceptible varieties of P. edulis, respectively. Overall, 126,284,018 clean reads were obtained, and 86,880 unigenes with a mean size of 1449 bp were assembled. Of these, there were 64,067 (73.74% unigenes with significant similarity to publicly available plant protein sequences. Expression profiles were generated, and 3045 genes were found to be significantly differentially expressed between the KEDU_AP and GX_AP libraries, including 1075 (35.3% up-regulated and 1970 (64.7% down-regulated. These included 36 genes in enriched pathways of plant hormone signal transduction, and 56 genes encoding putative transcription factors. Six genes involved in the ICE1–CBF–COR pathway were induced in the cold-tolerant variety, and their expression levels were further verified using quantitative real-time PCR. This report is the first to identify genes and signaling pathways involved in cold tolerance using high-throughput transcriptome sequencing in P. edulis. These findings may provide useful insights into the molecular mechanisms regulating cold tolerance and genetic breeding in Passiflora spp.

RNA-seq reveals a diminished acclimation response to the combined effects of ocean acidification and elevated seawater temperature in Pagothenia borchgrevinki.

Science.gov (United States)

Huth, Troy J; Place, Sean P

2016-08-01

The IPCC has reasserted the strong influence of anthropogenic CO2 contributions on global climate change and highlighted the polar-regions as highly vulnerable. With these predictions the cold adapted fauna endemic to the Southern Ocean, which is dominated by fishes of the sub-order Notothenioidei, will face considerable challenges in the near future. Recent physiological studies have demonstrated that the synergistic stressors of elevated temperature and ocean acidification have a considerable, although variable, impact on notothenioid fishes. The present study explored the transcriptomic response of Pagothenia borchgrevinki to increased temperatures and pCO2 after 7, 28 and 56days of acclimation. We compared this response to short term studies assessing heat stress alone and foretell the potential impacts of these stressors on P. borchgrevinki's ability to survive a changing Southern Ocean. P. borchgrevinki did demonstrate a coordinated stress response to the dual-stressor condition, and even indicated that some level of inducible heat shock response may be conserved in this notothenioid species. However, the stress response of P. borchgrevinki was considerably less robust than that observed previously in the closely related notothenioid, Trematomus bernacchii, and varied considerably when compared across different acclimation time-points. Furthermore, the molecular response of these fish under multiple stressors displayed distinct differences compared to their response to short term heat stress alone. When exposed to increased sea surface temperatures, combined with ocean acidification, P. borchgrevinki demonstrated a coordinated stress response that has already peaked by 7days of acclimation and quickly diminished over time. However, this response is less dramatic than other closely related notothenioids under identical conditions, supporting previous research suggesting that this notothenioid species is less sensitive to environmental variation. Copyright �

A specific glycerol kinase induces rapid cold hardening of the diamondback moth, Plutella xylostella.

Science.gov (United States)

Park, Youngjin; Kim, Yonggyun

2014-08-01

Insects in temperate zones survive low temperatures by migrating or tolerating the cold. The diamondback moth, Plutella xylostella, is a serious insect pest on cabbage and other cruciferous crops worldwide. We showed that P. xylostella became cold-tolerant by expressing rapid cold hardiness (RCH) in response to a brief exposure to moderately low temperature (4°C) for 7h along with glycerol accumulation in hemolymph. Glycerol played a crucial role in the cold-hardening process because exogenously supplying glycerol significantly increased the cold tolerance of P. xylostella larvae without cold acclimation. To determine the genetic factor(s) responsible for RCH and the increase of glycerol, four glycerol kinases (GKs), and glycerol-3-phosphate dehydrogenase (PxGPDH) were predicted from the whole P. xylostella genome and analyzed for their function associated with glycerol biosynthesis. All predicted genes were expressed, but differed in their expression during different developmental stages and in different tissues. Expression of the predicted genes was individually suppressed by RNA interference (RNAi) using double-stranded RNAs specific to target genes. RNAi of PxGPDH expression significantly suppressed RCH and glycerol accumulation. Only PxGK1 among the four GKs was responsible for RCH and glycerol accumulation. Furthermore, PxGK1 expression was significantly enhanced during RCH. These results indicate that a specific GK, the terminal enzyme to produce glycerol, is specifically inducible during RCH to accumulate the main cryoprotectant. Copyright © 2014 Elsevier Ltd. All rights reserved.

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 investiga...

Heat Acclimation and Water-Immersion Deconditioning: Responses to Exercise

Science.gov (United States)

Shvartz, E.; Bhattacharya, A.; Sperinde, S. J.; Brock, P. J.; Sciaraffa, D.; Haines, R. F.; Greenleaf, J. E.

1977-01-01

Simulated subgravity conditions, such as bed rest and water immersion, cause a decrease in a acceleration tolerance (3, 4), tilt tolerance (3, 9, 10), work capacity (5, 7), and plasma volume (1, 8-10). Moderate exercise training performed during bed rest (4) and prior to water immersion (5) provides some protection against the adverse effects of deconditioning, but the relationship between exercise and changes due to deconditioning remains unclear. Heat acclimation increases plasma and interstitial volumes, total body water, stroke volume (11), and tilt tolerance (6) and may, therefore, be a more efficient method of ameliorating deconditioning than physical training alone. The present study was undertaken to determine the effects of heat acclimation and moderate physical training, performed in cool conditions, on water-immersion deconditioning.

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.

Cardiorespiratory upregulation during seawater acclimation in rainbow trout: effects on gastrointestinal perfusion and postprandial responses.

Science.gov (United States)

Brijs, Jeroen; Gräns, Albin; Ekström, Andreas; Olsson, Catharina; Axelsson, Michael; Sandblom, Erik

2016-05-01

Increased gastrointestinal blood flow is essential for euryhaline fishes to maintain osmotic homeostasis during the initial phase of a transition from freshwater to seawater. However, the cardiorespiratory responses and hemodynamic changes required for a successful long-term transition to seawater remain largely unknown. In the present study, we simultaneously measured oxygen consumption rate (ṀO2), cardiac output (CO), heart rate (HR), and gastrointestinal blood flow (GBF) in rainbow trout (Oncorhynchus mykiss) acclimated to either freshwater or seawater for at least 6 wk. Seawater-acclimated trout displayed significantly elevated ṀO2 (day: 18%, night: 19%), CO (day: 22%, night: 48%), and GBF (day: 96%, night: 147%), demonstrating that an overall cardiorespiratory upregulation occurs during seawater acclimation. The elevated GBF was achieved via a combination of increased CO, mediated through elevated stroke volume (SV), and a redistribution of blood flow to the gastrointestinal tract. Interestingly, virtually all of the increase in CO of seawater-acclimated trout was directed to the gastrointestinal tract. Although unfed seawater-acclimated trout displayed substantially elevated cardiorespiratory activity, the ingestion of a meal resulted in a similar specific dynamic action (SDA) and postprandial GBF response as in freshwater-acclimated fish. This indicates that the capacity for the transportation of absorbed nutrients, gastrointestinal tissue oxygen delivery, and acid-base regulation is maintained during digestion in seawater. The novel findings presented in this study clearly demonstrate that euryhaline fish upregulate cardiovascular function when in seawater, while retaining sufficient capacity for the metabolic and cardiovascular changes associated with the postprandial response. Copyright © 2016 the American Physiological Society.

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.

Temperature acclimation of photosynthesis and respiration: A key uncertainty in the carbon cycle-climate feedback

Science.gov (United States)

Lombardozzi, Danica L.; Bonan, Gordon B.; Smith, Nicholas G.; Dukes, Jeffrey S.; Fisher, Rosie A.

2015-10-01

Earth System Models typically use static responses to temperature to calculate photosynthesis and respiration, but experimental evidence suggests that many plants acclimate to prevailing temperatures. We incorporated representations of photosynthetic and leaf respiratory temperature acclimation into the Community Land Model, the terrestrial component of the Community Earth System Model. These processes increased terrestrial carbon pools by 20 Pg C (22%) at the end of the 21st century under a business-as-usual (Representative Concentration Pathway 8.5) climate scenario. Including the less certain estimates of stem and root respiration acclimation increased terrestrial carbon pools by an additional 17 Pg C (~40% overall increase). High latitudes gained the most carbon with acclimation, and tropical carbon pools increased least. However, results from both of these regions remain uncertain; few relevant data exist for tropical and boreal plants or for extreme temperatures. Constraining these uncertainties will produce more realistic estimates of land carbon feedbacks throughout the 21st century.

Dicty_cDB: SSK863 [Dicty_cDB

Lifescience Database Archive (English)

Full Text Available 54 0.003 1 CB290208 |CB290208.1 UCRCS01_01aa10_g1 Washington Navel orange cold acclimated flavedo & albedo ...01_04cd07_g1 Washington Navel orange cold acclimated flavedo & albedo cDNA librar

Ethanol production from the seaweed Gelidium amansii, using specific sugar acclimated yeasts.

Science.gov (United States)

Cho, Hyeyoung; Ra, Chae-Hun; Kim, Sung-Koo

2014-02-28

For the production of ethanol from seaweed as the source material, thermal acid hydrolysis and enzymatic saccharification were carried out for monosugars production of 25.5 g/l galactose and 7.6 g/l glucose using Gelidium amansii. The fermentation was performed with Pichia stipitis KCTC 7228 or Saccharomyces cerevisiae KCCM 1129. When wild P. stipitis and S. cerevisiae were used, the ethanol productions of 11.2 g/l and 6.9 g/l were produced, respectively. The ethanol productions of 16.6 g/l and 14.6 g/l were produced using P. stipitis and S. cerevisiae acclimated to high concentration of galactose, respectively. The yields of ethanol fermentation increased to 0.5 and 0.44 from 0.34 and 0.21 using acclimated P. stipitis and S. cerevisiae, respectively. Therefore, acclimation of yeasts to a specific sugar such as galactose reduced the glucose-induced repression on the transport of galactose.

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.

Acclimation of photosynthesis to lightflecks in tomato leaves: interaction with progressive shading in a growing canopy

NARCIS (Netherlands)

Kaiser, M.E.; Matsubara, Shizue; Harbinson, J.; Heuvelink, E.; Marcelis, L.F.M.

2018-01-01

Plants in natural environments are often exposed to fluctuations in light intensity, and leaf-level acclimation to light may be affected by those fluctuations. Concurrently, leaves acclimated to a given light climate can become progressively shaded as new leaves emerge and grow above them.

Adenylate control contributes to thermal acclimation of sugar maple fine-root respiration in experimentally warmed soil.

Science.gov (United States)

Jarvi, Mickey P; Burton, Andrew J

2018-03-01

We investigated the occurrence of and mechanisms responsible for acclimation of fine-root respiration of mature sugar maple (Acer saccharum) after 3+ years of experimental soil warming (+4 to 5 °C) in a factorial combination with soil moisture addition. Potential mechanisms for thermal respiratory acclimation included changes in enzymatic capacity, as indicated by root N concentration; substrate limitation, assessed by examining nonstructural carbohydrates and effects of exogenous sugar additions; and adenylate control, examined as responses of root respiration to a respiratory uncoupling agent. Partial acclimation of fine-root respiration occurred in response to soil warming, causing specific root respiration to increase to a much lesser degree (14% to 26%) than would be expected for a 4 to 5 °C temperature increase (approximately 55%). Acclimation was greatest when ambient soil temperature was warmer or soil moisture availability was low. We found no evidence that enzyme or substrate limitation caused acclimation but did find evidence supporting adenylate control. The uncoupling agent caused a 1.4 times greater stimulation of respiration in roots from warmed soil. Sugar maple fine-root respiration in warmed soil was at least partially constrained by adenylate use, helping constrain respiration to that needed to support work being performed by the roots. © 2017 John Wiley & Sons Ltd.

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. © 2016 The Authors. New Phytologist © 2016 New Phytologist Trust.

The effect of chlorpyrifos on salinity acclimation of juvenile rainbow trout (Oncorhynchus mykiss).

Science.gov (United States)

Amiri, Bagher Mojazi; Xu, Elvis Genbo; Kupsco, Allison; Giroux, Marissa; Hoseinzadeh, Mahbubeh; Schlenk, Daniel

2018-02-01

As a part of their unique life cycle, most salmonids undergo a transition from fresh water to salt water requiring various adjustments in metabolism, osmoregulation and ion regulation. Exposure to pesticides may affect the acclimation of juvenile salmonids to salt water during downstream migration to estuaries. Using the Caspian Sea as a model waterbody, the present study aimed to determine how the toxicity of the organophosphate pesticide chlorpyrifos (CPF) impacts saline acclimation of rainbow trout (Oncorhynchus mykiss). We pre-exposed 4-month-old fish to nominal concentrations of 0, 20, 40, 80, 160 μg/L of CPF for seven days, and then gradually to salinity (12 ppt) for another seven days. Mortality, levels of cortisol, T3 and T4 in serum, and expression of genes involved in gill ion transport (Na + /K + ATPase α1a and α1b) and liver xenobiotic detoxification (Glutathione-S-Transferase pi, GST) were measured at day fourteen. Cortisol concentrations in serum were not changed by CPF exposure in freshwater, but serum T3 increased up to three fold relative to controls in freshwater. Following salinity acclimation, T3 and T4 concentrations in the serum were both increased up to 2.5 and 8.8 fold in animals treated with CPF followed by saltwater. Na+/K + ATPase α1a and α1b mRNA in gill were unchanged by CPF treatment in freshwater but trended higher in CPF-treated animals after salinity acclimation. Hepatic mRNA of GST was significantly increased following exposure to CPF but was unchanged after saltwater exposure. Although saltwater treatment reduced the acute lethality of CPF, changes in T3/T4 suggest sublethal impacts may occur in CPF-treated fish after they acclimate to Caspian seawater. Copyright © 2017 Elsevier B.V. All rights reserved.

Dicty_cDB: VSD136 [Dicty_cDB

Lifescience Database Archive (English)

Full Text Available 8 |CB290208.1 UCRCS01_01aa10_g1 Washington Navel orange cold acclimated flavedo & albedo cDNA library Citrus....1 UCRCS01_04cd07_g1 Washington Navel orange cold acclimated flavedo & albedo cDNA library Citrus sinensis c

Dicty_cDB: VFD555 [Dicty_cDB

Lifescience Database Archive (English)

Full Text Available ashington Navel orange cold acclimated flavedo & albedo cDNA library Citrus sinensis cDNA clone UCRCS01_01aa...10, mRNA sequence. 54 0.003 1 CB292489 |CB292489.1 UCRCS01_04cd07_g1 Washington Navel orange cold acclimated

Mechanisms of fenthion activation in rainbow trout (Oncorhynchus mykiss) acclimated to hypersaline environments

International Nuclear Information System (INIS)

Lavado, Ramon; Rimoldi, John M.; Schlenk, Daniel

2009-01-01

Previous studies in rainbow trout have shown that acclimation to hypersaline environments enhances the toxicity to thioether organophosphate and carbamate pesticides. In order to determine the role of biotransformation in this process, the metabolism of the thioether organophosphate biocide, fenthion was evaluated in microsomes from gills, liver and olfactory tissues in rainbow trout (Oncorhynchus mykiss) acclimated to freshwater and 17 per mille salinity. Hypersalinity acclimation increased the formation of fenoxon and fenoxon sulfoxide from fenthion in liver microsomes from rainbow trout, but not in gills or in olfactory tissues. NADPH-dependent and independent hydrolysis was observed in all tissues, but only NADPH-dependent fenthion cleavage was differentially modulated by hypersalinity in liver (inhibited) and gills (induced). Enantiomers of fenthion sulfoxide (65% and 35% R- and S-fenthion sulfoxide, respectively) were formed in liver and gills. The predominant pathway of fenthion activation in freshwater appears to be initiated through initial formation of fenoxon which may be subsequently converted to the most toxic metabolite fenoxon R-sulfoxide. However, in hypersaline conditions both fenoxon and fenthion sulfoxide formation may precede fenoxon sulfoxide formation. Stereochemical evaluation of sulfoxide formation, cytochrome P450 inhibition studies with ketoconazole and immunoblots indicated that CYP3A27 was primarily involved in the enhancement of fenthion activation in hypersaline-acclimated fish with limited contribution of FMO to initial sulfoxidation

Acclimation capability of Calamagrostis epigejos and C. arundinacea to changes in radiation environment

Energy Technology Data Exchange (ETDEWEB)

Gloser, V.; Gloser, J. [Masarykova Univ., Brno (Czech Republic)

1996-03-15

Three different approaches were used in quantification of acclimation capability of perennial grasses colonizing deforested areas: (a) nondestructive estimation of their relative growth rate (RGR), (b) analysis of photosynthetic and respiratory characteristics of individual organs, (c) measurement and calculation of the whole plant carbon balance over the 24 h cycle. The experiments were made in controlled conditions with plants growing continuously in extremely low photosynthetic photon flux (PPF), 25 mu-mol m{sup -2} s{sup -1}, and at moderately high PPF (200 mu-mol m{sup -2} s{sup -1}). Responses of plants to reciprocal transfer between low and high PPF environment were also studied. Fully acclimated plants of both species grew successfully at low PPF (LI) with RGR of about 20 to 40 g kg{sup -1} d{sup -1}, and increased their RGR three to five times immediately after transfer to high PPF (HI). Lowered respiration rate and acclimation to LI. Variation in the net photosynthetic rates per unit leaf area (P{sub N}) did not contribute significantly to acclimation. C. epigejos had considerably higher RGR under both irradiances, although its photosynthetic characteristics (P{sub N} and apparent quantum yield) were not better than those of C. arundinacea. Higher values of SLA were of key importance for better performance of C. epigejos under both LI and HI. (author)

Acclimation of mechanical and hydraulic functions in trees:Impact of the thigmomorphogenetic process

Directory of Open Access Journals (Sweden)

Eric eBadel

2015-04-01

Full Text Available The secondary xylem (wood of trees mediates several functions including water transport and storage, mechanical support and storage of photosynthates. The optimal structures for each of these functions will most likely differ. The complex structure and function of xylem could lead to trade-offs between conductive efficiency, resistance to embolism and mechanical strength needed to count for mechanical loading due to gravity and wind. This has been referred to as the trade-off triangle, with the different optimal solutions to the structure/function problems depending on the environmental constraints as well as taxonomic histories. Thus, the optimisation of each function will lead to drastically different anatomical structures. Trees are able to acclimate the internal structure of their trunk and branches according to the stress they experience. These acclimations lead to specific structures that favour the efficiency or the safety of one function but can be antagonistic with other functions. Currently, there are no means to predict the way a tree will acclimate or optimize its internal structure in support of its various functions under differing environmental conditions. In this review, we will focus on the acclimation of xylem anatomy and its resulting mechanical and hydraulic functions to recurrent mechanical strain that usually result from wind-induced thigmomorphogenesis with a special focus on the construction cost and the possible trade-off between wood functions.

Working in the Cold

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During the winter, many workers are outdoors, working in cold, wet, icy, or snowy conditions. Learn how to identify symptoms that tell you there may be a problem and protect yourself from cold stress.

Acclimation responses to high light by Guazuma ulmifolia Lam. (Malvaceae) leaves at different stages of development.

Science.gov (United States)

Calzavara, A K; Rocha, J S; Lourenço, G; Sanada, K; Medri, C; Bianchini, E; Pimenta, J A; Stolf-Moreira, R; Oliveira, H C

2017-09-01

The re-composition of deforested environments requires the prior acclimation of seedlings to full sun in nurseries. Seedlings can overcome excess light either through the acclimation of pre-existing fully expanded leaves or through the development of new leaves that are acclimated to the new light environment. Here, we compared the acclimation capacity of mature (MatL, fully expanded at the time of transfer) and newly expanded (NewL, expanded after the light shift) leaves of Guazuma ulmifolia Lam. (Malvaceae) seedlings to high light. The seedlings were initially grown under shade and then transferred to full sunlight. MatL and NewL were used for chlorophyll fluorescence and gas exchange analyses, pigment extraction and morpho-anatomical measurements. After the transfer of seedlings to full sun, the MatL persisted and acclimated to some extent to the new light condition, since they underwent alterations in some morpho-physiological traits and maintained a functional electron transport chain and positive net photosynthesis rate. However, long-term exposure to high light led to chronic photoinhibition in MatL, which could be related to the limited plasticity of leaf morpho-anatomical attributes. However, the NewL showed a high capacity to use the absorbed energy in photochemistry and dissipate excess energy harmlessly, attributes that were favoured by the high structural plasticity exhibited by these leaves. Both the maintenance of mature, photosynthetically active leaves and the production of new leaves with a high capacity to cope with excess energy were important for acclimation of G. ulmifolia seedlings. © 2017 German Botanical Society and The Royal Botanical Society of the Netherlands.

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.

2014-01-01

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. PMID:24854764

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.

Towards improved behavioural testing in aquatic toxicology: Acclimation and observation times are important factors when designing behavioural tests with fish.

Science.gov (United States)

Melvin, Steven D; Petit, Marie A; Duvignacq, Marion C; Sumpter, John P

2017-08-01

The quality and reproducibility of science has recently come under scrutiny, with criticisms spanning disciplines. In aquatic toxicology, behavioural tests are currently an area of controversy since inconsistent findings have been highlighted and attributed to poor quality science. The problem likely relates to limitations to our understanding of basic behavioural patterns, which can influence our ability to design statistically robust experiments yielding ecologically relevant data. The present study takes a first step towards understanding baseline behaviours in fish, including how basic choices in experimental design might influence behavioural outcomes and interpretations in aquatic toxicology. Specifically, we explored how fish acclimate to behavioural arenas and how different lengths of observation time impact estimates of basic swimming parameters (i.e., average, maximum and angular velocity). We performed a semi-quantitative literature review to place our findings in the context of the published literature describing behavioural tests with fish. Our results demonstrate that fish fundamentally change their swimming behaviour over time, and that acclimation and observational timeframes may therefore have implications for influencing both the ecological relevance and statistical robustness of behavioural toxicity tests. Our review identified 165 studies describing behavioural responses in fish exposed to various stressors, and revealed that the majority of publications documenting fish behavioural responses report extremely brief acclimation times and observational durations, which helps explain inconsistencies identified across studies. We recommend that researchers applying behavioural tests with fish, and other species, apply a similar framework to better understand baseline behaviours and the implications of design choices for influencing study outcomes. Copyright © 2017 Elsevier Ltd. All rights reserved.

Thermoregulatory efficiency is increased after heat acclimation in tropical natives.

Science.gov (United States)

Magalhães, Flávio C; Passos, Renata L F; Fonseca, Michele A; Oliveira, Kenya P M; Ferreira-Júnior, João B; Martini, Angelo R P; Lima, Milene R M; Guimarães, Juliana B; Baraúna, Valério G; Silami-Garcia, Emerson; Rodrigues, Luiz O C

2010-01-01

To evaluate the effects of heat acclimation on sweat rate redistribution and thermodynamic parameters, 9 tropical native volunteers were submitted to 11 days of exercise-heat exposures (40+/-0 degrees C and 45.1+/-0.2% relative humidity). Sudomotor function was evaluated by measuring total and local (forehead, chest, arm, forearm, and thigh) sweat rates, local sweat sodium concentration, and mean skin and rectal temperatures. We also calculated heat production (H), heat storage (S), heat exchange by radiation (R) and by convection (C), evaporated sweat (E(sw)), sweating efficiency (eta(sw)), skin wettedness (w(sk)), and the ratio between the heat storage and the sum of heat production and heat gains by radiation and convection (S/(H+R+C)). The heat acclimation increased the whole-body sweat rate and reduced the mean skin temperature. There were changes in the local sweat rate patterns: on the arm, forearm, and thigh it increased significantly from day 1 to day 11 (all p<0.05) and the sweat rates from the forehead and the chest showed a small nonsignificant increase (p=0.34 and 0.17, respectively). The relative increase of local sweat rates on day 11 was not different among the sites; however, when comparing the limbs (arm, forearm, and thigh) with the trunk (forehead and chest), there was a significant higher increase in the limbs (32+/-5%) in comparison to the trunk (11+/-2%, p=0.001). After the heat acclimation period we observed higher w(sk) and E(sw) and reduced S/(H+R+C), meaning greater thermoregulatory efficiency. The increase in the limb sweat rate, but not the increase in the trunk sweat rate, correlated with the increased w(sk), E(sw), and reduced S/(H+R+C) (p<0.05 to all). Altogether, it can be concluded that heat acclimation increased the limbs' sweat rates in tropical natives and that this increase led to increased loss of heat through evaporation of sweat and this higher sweat evaporation was related to higher thermoregulatory efficiency.

Copper regulation and homeostasis of Daphnia magna and Pseudokirchneriella subcapitata: influence of acclimation

International Nuclear Information System (INIS)

Bossuyt, Bart T.A.; Janssen, Colin R.

2005-01-01

This study aimed to evaluate (1) the capacity of the green alga Pseudokirchneriella subcapitata and the waterflea Daphnia magna to regulate copper when exposed to environmentally realistic copper concentrations and (2) the influence of multi-generation acclimation to these copper concentrations on copper bioaccumulation and homeostasis. Based on bioconcentration factors, active copper regulation was observed in algae up to 5 μg Cu L -1 and in daphnids up to 35 μg Cu L -1 . Constant body copper concentrations (13 ± 4 μg Cu g DW -1 ) were observed in algae exposed to 1 through 5 μg Cu L -1 and in daphnids exposed to 1 through 12 μg Cu L -1 . At higher exposure concentrations, there was an increase in internal body copper concentration, while no increase was observed in bioconcentration factors, suggesting the presence of a storage mechanism. At copper concentrations of 100 μg Cu L -1 (P. subcapitata) and 150 μg Cu L -1 (D. magna), the significant increases observed in body copper concentrations and in bioconcentration factors may be related to a failure of this regulation mechanism. For both organisms, internal body copper concentrations lower than 13 μg Cu g DW -1 may result in copper deficiency. For P. subcapitata acclimated to 0.5 and 100 μg Cu L -1 , body copper concentrations ranged (mean ± standard deviation) between 5 ± 2 μg Cu g DW -1 and 1300 ± 197 μg Cu g DW -1 , respectively. For D. magna, this value ranged between 9 ± 2 μg Cu g DW -1 and 175 ± 17 μg Cu g DW -1 for daphnids acclimated to 0.5 and 150 μg Cu L -1 . Multi-generation acclimation to copper concentrations ≥12 μg Cu L -1 resulted in a decrease (up to 40%) in body copper concentrations for both organisms compared to the body copper concentration of the first generation. It can be concluded that there is an indication that P. subcapitata and D. magna can regulate their whole body copper concentration to maintain copper homeostasis within their optimal copper range and

Cold stress alters transcription in meiotic anthers of cold tolerant chickpea (Cicer arietinum L.).

Science.gov (United States)

Sharma, Kamal Dev; Nayyar, Harsh

2014-10-11

Cold stress at reproductive phase in susceptible chickpea (Cicer arietinum L.) leads to pollen sterility induced flower abortion. The tolerant genotypes, on the other hand, produce viable pollen and set seed under cold stress. Genomic information on pollen development in cold-tolerant chickpea under cold stress is currently unavailable. DDRT-PCR analysis was carried out to identify anther genes involved in cold tolerance in chickpea genotype ICC16349 (cold-tolerant). A total of 9205 EST bands were analyzed. Cold stress altered expression of 127 ESTs (90 up-regulated, 37 down-regulated) in anthers, more than two third (92) of which were novel with unknown protein identity and function. Remaining about one third (35) belonged to several functional categories such as pollen development, signal transduction, ion transport, transcription, carbohydrate metabolism, translation, energy and cell division. The categories with more number of transcripts were carbohydrate/triacylglycerol metabolism, signal transduction, pollen development and transport. All but two transcripts in these categories were up-regulated under cold stress. To identify time of regulation after stress and organ specificity, expression levels of 25 differentially regulated transcripts were also studied in anthers at six time points and in four organs (anthers, gynoecium, leaves and roots) at four time points. Limited number of genes were involved in regulating cold tolerance in chickpea anthers. Moreover, the cold tolerance was manifested by up-regulation of majority of the differentially expressed transcripts. The anthers appeared to employ dual cold tolerance mechanism based on their protection from cold by enhancing triacylglycerol and carbohydrate metabolism; and maintenance of normal pollen development by regulating pollen development genes. Functional characterization of about two third of the novel genes is needed to have precise understanding of the cold tolerance mechanisms in chickpea anthers.

Impaired control of body cooling during heterothermia represents the major energetic constraint in an aging non-human primate exposed to cold.

Directory of Open Access Journals (Sweden)

Jeremy Terrien

2009-10-01

Full Text Available Daily heterothermia is used by small mammals for energy and water savings, and seems to be preferentially exhibited during winter rather than during summer. This feature induces a trade-off between the energy saved during daily heterothermia and the energy cost of arousal, which can impact energy balance and survival under harsh environmental conditions. Especially, aging may significantly affect such trade off during cold-induced energy stress, but direct evidences are still lacking. We hypothesized that aging could alter the energetics of daily heterothermia, and that the effects could differ according to season. In the gray mouse lemur (Microcebus murinus, a non-human primate species which exhibits daily heterothermia, we investigated the effects of exposures to 25 and 12 degrees C on body composition, energy balance, patterns of heterothermia and water turnover in adult (N = 8 and aged animals (N = 7 acclimated to winter-like or summer-like photoperiods. Acclimation to summer prevented animals from deep heterothermia, even during aging. During winter, adult animals at 12 degrees C and aged animals at 25 degrees C exhibited low levels of energy expenditure with minor modulations of heterothermia. The major effects of cold were observed during winter, and were particularly pronounced in aged mouse lemurs which exhibited deep heterothermia phases. Body composition was not significantly affected by age and could not explain the age-related differences in heterothermia patterns. However, aging was associated with increased levels of energy expenditure during cold exposure, in concomitance with impaired energy balance. Interestingly, increased energy expenditure and depth of heterothermia phases were strongly correlated. In conclusion, it appeared that the exhibition of shallow heterothermia allowed energy savings during winter in adult animals only. Aged animals exhibited deep heterothermia and increased levels of energy expenditure, impairing

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.

Changes in the microbial community during the acclimation stages of the methane fermentation for the treatment of glycerol

International Nuclear Information System (INIS)

Dinh, Nga Thi; Hatta, Kohei; Kwon, Sang Hagk; Rollon, Analiza P.; Nakasaki, Kiyohiko

2014-01-01

Granular sludge from a full-scale methane reactor treating brewery wastewater was used as a seed for the treatment of glycerol in a laboratory-scale repeated-batch methane reactor, and the change in the microbial community during the acclimation stages was examined. Two types of substrate solutions, a glucose, sodium acetate, and lactic acid mixture, as well as glycerol, were prepared and fed by mixing the two solutions to increase the ratio, in a stepwise manner, of glycerol from 0% to 100%, while keeping a loading of COD at 2.5 kg m −3  d −1 throughout the fermentation process. Vigorous methane gas production, approximately 580 dm 3  m −3  d −1 , was observed during the acclimation stages. Microbial analysis revealed that both bacterial and archaeal communities changed significantly; bacteria (genus Trichococcus and family Syntrophomonadaceae) became dominant rapidly after the start of acclimation, and archaea belonging to the hydrogenotrophic methanogens (genera Methanobacterium and Methanospirillum), increased gradually with the progress of acclimation. - Highlights: • Acclimation stages to the methane fermentation of glycerol were examined. • Vigorous methane gas production, approximately 580 dm 3  m −3  d −1 , was observed. • Both bacteria and archaea, changed significantly during the acclimation stages. • Bacteria belonging to genus Trichococcus and Syntrophomonadaceae became dominant. • Archaea belonging to the hydrogenotrophic methanogens increased gradually

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 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 = 0.01) concentrations of cortisol and haptoglobin on d 40 and reduced (P = 0.02) exit velocity on d 200 compared with control heifers. Puberty was hastened in acclimated heifers compared with control (P = 0.01). Results from this study indicate that B. taurus beef cows with aggressive temperament have impaired reproductive performance compared with cohorts with adequate temperament, whereas acclimation to human handling after weaning hastens reproductive development of

Dicty_cDB: SHH148 [Dicty_cDB

Lifescience Database Archive (English)

Full Text Available ents: (bits) Value N CB292163 |CB292163.1 UCRCS01_04ac07_g1 Washington Navel orange cold acclimated flavedo ...WORKING DRAFT SEQUENCE, in ordered pieces. 34 0.27 2 CB292162 |CB292162.1 UCRCS01_04ac07_b1 Washington Navel orange cold acclimate

Whole-body fluid distribution in humans during dehydration and recovery, before and after humid-heat acclimation induced using controlled hyperthermia.

Science.gov (United States)

Patterson, M J; Stocks, J M; Taylor, N A S

2014-04-01

This experiment was designed to test the hypothesis that the plasma volume is not selectively defended during exercise- and heat-induced dehydration following humid-heat acclimation. Eight physically active males were heat acclimated (39.8 °C, relative humidity 59.2%) using 17 days of controlled hyperthermia (core temperature: 38.5 °C). Inter-compartmental fluid losses and movements were tracked (radioisotopes and Evans blue dye) during progressive dehydration (cycling) in these same conditions and also during a resting recovery without fluid replacement (28 °C), before (day 1), during (day 8) and after heat acclimation (day 22). On days 8 and 22, there were significant increases in total body water, interstitial fluid and plasma volume (P 0.05). The baseline plasma volume remained expanded throughout: 43.4 [±2.6 (day 1)], 49.1 [±2.4 (day 8); P recovery, plasma volume restoration commenced, with the intracellular fluid contribution becoming more pronounced as acclimation progressed. It is concluded that the plasma volume was not defended more vigorously following humid-heat acclimation. Indeed, a greater fluid loss may well underlie the mechanisms for enhancing plasma volume recovery when heat acclimation is induced using the controlled-hyperthermia technique. © 2013 Scandinavian Physiological Society. Published by John Wiley & Sons Ltd.

Acclimation-dependent expression of heat shock protein 70 in Pacific abalone ( Haliotis discus hannai Ino) and its acute response to thermal exposure

Science.gov (United States)

Li, Jiaqi; He, Qingguo; Sun, Hui; Liu, Xiao

2012-01-01

Heat shock protein 70 (Hsp70) is one important member of heat shock protein (Hsp) family that is responsible for various stresses, especially thermal stress. Here we examined the response of Hsp70 gene to both chronic and acute thermal exposure in Pacific abalone ( Haliotis discus hannai Ino). For the chronic exposure, abalones were maintained at 8, 12, 20, and 30°C for four months and their mRNA levels were measured. The highest mRNA level of Hsp70 gene relative to actin gene was detected in the 30°C-acclimated group, followed by the 8°C-acclimated group and then the 12°C- and 20°C-acclimated groups. After the long-term acclimation, gills from each of the above acclimation groups were dissected and exposed to different temperatures between 8°C and 38°C for 30 min. Hsp70 expression in gills acclimated to different temperatures responded differentially to the same temperature exposure. The incubation temperature that induced maximum Hsp70 mRNA expression was higher in the higher temperature acclimation groups than lower temperature groups. Pacific abalones could alter the expression pattern of Hsp70 gene according to environmental thermal conditions, through which they deal with the stress of thermal variations.

Cold Exposure Induces Proliferation of Mature Brown Adipocyte in a ß3-Adrenergic Receptor-Mediated Pathway.

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Fukano, Keigo; Okamatsu-Ogura, Yuko; Tsubota, Ayumi; Nio-Kobayashi, Junko; Kimura, Kazuhiro

2016-01-01

Hyperplasia of brown adipose tissue (BAT) is a fundamental mechanism for adaptation to survive in the cold environment in rodents. To determine which cell types comprising BAT contribute to tissue hyperplasia, immunohistochemical analysis using a proliferative marker Ki67 was performed on the BAT from 6-week-old C57BL/6J mice housed at 23°C (control) or 10°C (cold) for 5 days. Interestingly, in the control group, the cell proliferative marker Ki67 was detected in the nuclei of uncoupling protein 1-positive mature brown adipocytes (7.2% ± 0.4% of brown adipocyte), as well as in the non-adipocyte stromal-vascular (SV) cells (19.6% ± 2.3% of SV cells), which include preadiopocytes. The percentage of Ki67-positive brown adipocytes increased to 25.6% ± 1.8% at Day 1 after cold exposure and was significantly higher than the non-cold acclimated control until Day 5 (21.8% ± 1.7%). On the other hand, the percentage of Ki67-positive SV cells gradually increased by a cold exposure and peaked to 42.1% ± 8.3% at Day 5. Injection of a ß3-adrenergic receptor (ß3-AR) agonist for continuous 5 days increased the number of Ki67-positive brown adipocytes even at Day 1 but not that of SV cells. In addition, the ß3-AR antagonist, but not ß1-AR antagonist, attenuated the cold exposure-induced increase in the number of Ki67-positive brown adipocytes. These results suggest that mature brown adipocytes proliferate immediately after cold exposure in a ß3-AR-mediated pathway. Thus, proliferation of mature brown adipocytes as well as preadipocytes in SV cells may contribute to cold exposure-induced BAT hyperplasia.

The influence of acclimation temperature on the lipid composition of the larval lamprey, Petromyzon marinus, depends on tissue and lipid class.

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Kao, Yung-Hsi; Sheridan, Mark A; Holmes, John A; Youson, John H

2010-11-01

This study was designed to examine the effect of thermal acclimation on the lipid composition of fat depot organs the liver and kidneys of larval sea lamprey, Petromyzon marinus. We found that 21 °C-acclimated larvae possessed lower total lipid amounts in the liver (39% lower) and kidneys (30% lower) than 13 °C-acclimated larvae. Relatively lower lipid contents in the liver and kidneys of 21 °C-acclimated lamprey primarily resulted from a reduction in stored lipid reserve, triacylglycerol, but not the structural lipid, phospholipid. Compared to 21 °C-acclimated larvae, 13 °C-acclimated larvae were found to possess fewer saturated fatty acids (SFAs) and more unsaturated fatty acids (USFAs) in renal triacylglycerol and phospholipid classes, while there were no significant differences in the SFAs and USFAs of hepatic triacylglycerol, phospholipid, cholesteryl ester, fatty acid, and monoacylglycerol classes. Fewer SFAs, found in the kidney triacylglycerol of 13 °C-acclimated lamprey, were due to lower 12:0 and 14:0 fatty acids, but those in the renal phospholipid class were characterized by fewer 14:0, 15:0, and 16:0 fatty acids. More USFAs in renal triacylglycerol, as indicated by a higher unsaturation index, primarily resulted from higher polyunsaturated fatty acids (18:2ω6, 18:3ω3, and 18:4ω3); whereas, in the renal phospholipid class, this was a result of higher monoenes (18:1, 20:1, and 22:1ω9) and ω3 polyunsaturated fatty acids (18:4ω3). These data suggest that the influence of thermal acclimation on the lipid composition of lamprey fat depot organs depends on tissue and lipid class.

The protective effect of rapid cold-hardening develops more quickly in frozen versus supercooled larvae of the Antarctic midge, Belgica antarctica.

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Kawarasaki, Yuta; Teets, Nicholas M; Denlinger, David L; Lee, Richard E

2013-10-15

During the austral summer, larvae of the terrestrial midge Belgica antarctica (Diptera: Chironomidae) experience highly variable and often unpredictable thermal conditions. In addition to remaining freeze tolerant year-round, larvae are capable of swiftly increasing their cold tolerance through the rapid cold-hardening (RCH) response. The present study compared the induction of RCH in frozen versus supercooled larvae. At the same induction temperature, RCH occurred more rapidly and conferred a greater level of cryoprotection in frozen versus supercooled larvae. Furthermore, RCH in frozen larvae could be induced at temperatures as low as -12°C, which is the lowest temperature reported to induce RCH. Remarkably, as little as 15 min at -5°C significantly enhanced larval cold tolerance. Not only is protection from RCH acquired swiftly, but it is also quickly lost after thawing for 2 h at 2°C. Because the primary difference between frozen and supercooled larvae is cellular dehydration caused by freeze concentration of body fluids, we also compared the effects of acclimation in dehydrated versus frozen larvae. Because slow dehydration without chilling significantly increased larval survival to a subsequent cold exposure, we hypothesize that cellular dehydration caused by freeze concentration promotes the rapid acquisition of cold tolerance in frozen larvae.

Cold Pain Threshold Identifies a Subgroup of Individuals With Knee Osteoarthritis That Present With Multimodality Hyperalgesia and Elevated Pain Levels.

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Wright, Anthony; Benson, Heather A E; Will, Rob; Moss, Penny

2017-09-01

Cold hyperalgesia has been established as an important marker of pain severity in a number of conditions. This study aimed to establish the extent to which patients with knee osteoarthritis (OA) demonstrate widespread cold, heat, and pressure hyperalgesia. OA participants with widespread cold hyperalgesia were compared with the remaining OA cohort to determine whether they could be distinguished in terms of hyperalgesia, pain report, pain quality, and physical function. A total of 80 participants with knee OA and 40 matched healthy, pain-free controls participated. OA participants completed a washout of their usual medication. Quantitative sensory testing was completed at 3 sites using standard methods. Cold pain threshold (CPT) and heat pain thresholds (HPT) were tested using a Peltier thermode and pressure pain thresholds (PPT) using a digital algometer. All participants completed the short-form health survey questionnaire and OA participants completed the PainDETECT, Western Ontario and McMaster Universities Osteoarthritis Index of the Knee (WOMAC), and pain quality assessment scale questionnaires. OA participants demonstrated widespread cold hyperalgesia (Ppain, decreased function, and more features of neuropathic pain. This study identified a specific subgroup of patients with knee OA who exhibited widespread, multimodality hyperalgesia, more pain, more features of neuropathic pain, and greater functional impairment. Identification of patients with this pain phenotype may permit more targeted and effective pain management.

Dicty_cDB: SLJ826 [Dicty_cDB

Lifescience Database Archive (English)

Full Text Available 033B22f, mRNA sequence. 50 0.023 1 CB290319 |CB290319.1 UCRCS01_01ag06_g1 Washington Navel orange cold acclimate... mRNA sequence. 50 0.023 1 CB290210 |CB290210.1 UCRCS01_01aa11_g1 Washington Navel orange cold acclimated fl

Long-term water stress leads to acclimation of drought sensitivity of photosynthetic capacity in xeric but not riparian Eucalyptus species.

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Zhou, Shuang-Xi; Medlyn, Belinda E; Prentice, Iain Colin

2016-01-01

Experimental drought is well documented to induce a decline in photosynthetic capacity. However, if given time to acclimate to low water availability, the photosynthetic responses of plants to low soil moisture content may differ from those found in short-term experiments. This study aims to test whether plants acclimate to long-term water stress by modifying the functional relationships between photosynthetic traits and water stress, and whether species of contrasting habitat differ in their degree of acclimation. Three Eucalyptus taxa from xeric and riparian habitats were compared with regard to their gas exchange responses under short- and long-term drought. Photosynthetic parameters were measured after 2 and 4 months of watering treatments, namely field capacity or partial drought. At 4 months, all plants were watered to field capacity, then watering was stopped. Further measurements were made during the subsequent 'drying-down', continuing until stomata were closed. Two months of partial drought consistently reduced assimilation rate, stomatal sensitivity parameters (g1), apparent maximum Rubisco activity (V'(cmax)) and maximum electron transport rate (J'(max)). Eucalyptus occidentalis from the xeric habitat showed the smallest decline in V'(cmax) and J'(max); however, after 4 months, V'(cmax) and J'(max) had recovered. Species differed in their degree of V'(cmax) acclimation. Eucalyptus occidentalis showed significant acclimation of the pre-dawn leaf water potential at which the V'(cmax) and 'true' V(cmax) (accounting for mesophyll conductance) declined most steeply during drying-down. The findings indicate carbon loss under prolonged drought could be over-estimated without accounting for acclimation. In particular, (1) species from contrasting habitats differed in the magnitude of V'(cmax) reduction in short-term drought; (2) long-term drought allowed the possibility of acclimation, such that V'(cmax) reduction was mitigated; (3) xeric species showed a

Physiological responses of horses to a treadmill simulated speed and endurance test in high heat and humidity before and after humid heat acclimation.

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Marlin, D J; Scott, C M; Schroter, R C; Harris, R C; Harris, P A; Roberts, C A; Mills, P C

1999-01-01

To investigate whether horses were able to acclimate to conditions of high temperature and humidity, 5 horses of different breeds were trained for 80 min on 15 consecutive days on a treadmill at 30 degrees C and 80%RH. Training consisted of a combination of long duration low-intensity exercise, medium duration medium intensity exercise and short duration high intensity exercise. Between training sessions the horses were maintained at 11+/-3 degrees C and 74+/-2%RH. Before (PRE-ACC) and after acclimation (POST-ACC) the horses undertook a simulated Competition Exercise Test (CET), designed to represent the Speed and Endurance Test of a 3-day event, at 30 degrees C/80%RH. Maximal oxygen uptake (VO2PEAK) was not changed following acclimation (PRE-ACC 141+/-8 ml/min/kg bwt vs. POST-ACC 145+/-9 ml/min/kg bwt [STPD], P>0.05). Following acclimation, 4 of the 5 horses were able to complete a significantly greater amount of Phase D in the CET (PRE-ACC 6.3+/-0.3 min vs. POST-ACC 7.3+/-0.3 min, P<0.05; target time = 8 min). Resting body temperatures (pulmonary artery [TPA], rectal [TREC] and tail-skin [TTSK] temperatures) were all significantly lower following acclimation. During exercise, metabolic heat production (M) and heat dissipation (HD), for the same exercise duration, were both significantly lower following acclimation (P<0.05), although heat storage (HS) was significantly higher (P<0.05). The higher heat storage following acclimation was associated with a lower TTSK for a given TPA and a decreased total fluid loss (% bodyweight, P<0.05). Plasma volume was not changed following acclimation. The relationship of sweating rate (SR) to TPA or TTSK on either the neck or the gluteal region was not significantly altered by acclimation, although the onset of sweating occurred at a lower TPA or TTSK following acclimation (P<0.05). The horses in the present study showed a number of physiological adaptations to a period of 15 days of exposure to high heat and humidity consistent

Expression dynamics of HSP90 and nitric oxide synthase (NOS) isoforms during heat stress acclimation in Tharparkar cattle

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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 heat stress exposure in Tharparkar cattle.

Precooling With Crushed Ice: As Effective as Heat Acclimation at Improving Cycling Time-Trial Performance in the Heat.

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Zimmermann, Matthew; Landers, Grant; Wallman, Karen; Kent, Georgina

2018-02-01

This study compared the effects of precooling (ice ingestion) and heat-acclimation training on cycling time-trial (CTT) performance in the heat. Fifteen male cyclists/triathletes completed two 800-kJ CTTs in the heat, with a 12-d training program in between. Initially, all participants consumed 7 g/kg of water (22°C) in 30 min before completing an 800-kJ CTT in hot, humid conditions (pre-CTT) (35°C, 50% relative humidity [RH]). Participants were then split into 2 groups, with the precooling group (n = 7) training in thermoneutral conditions and then undergoing precooling with ice ingestion (7 g/kg, 1°C) prior to the final CTT (post-CTT) and the heat-acclimation group (n = 8) training in hot conditions (35°C, 50% RH) and consuming water (7 g/kg) prior to post-CTT. After training in both conditions, improvement in CTT time was deemed a likely positive benefit (precooling -166 ± 133 s, heat acclimation -105 ± 62 s), with this result being similar between conditions (d = 0.22, -0.68-1.08 90% confidence interval [CI]). Core temperature for post-CTT was lower in precooling than in heat acclimation from 20 min into the precooling period until the 100-kJ mark of the CTT (d > 0.98). Sweat onset occurred later in precooling (250 ± 100 s) than in heat acclimation (180 ± 80 s) for post-CTT (d = 0.65, -0.30-1.50 90% CI). Thermal sensation was lower at the end of the precooling period prior to post-CTT for the precooling trial than with heat acclimation (d = 1.24, 0.90-1.58 90% CI). Precooling with ice ingestion offers an alternative method of improving endurance-cycling performance in hot conditions if heat acclimation cannot be attained.

Neuroprotection against oxidative stress by serum from heat acclimated rats.

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Beit-Yannai, E; Trembovler, V; Horowitz, M; Lazarovici, P; Kohen, R; Shohami, E

1998-09-25

Exposure of PC12 cells, to 1% serum derived from normothermic (CON) rats resulted in 79% cell death. Sister cultures treated with 1% serum derived from heat acclimated (ACC) rats, were neuroprotected and expressed a significant reduction in cell death. In PC12 cells exposed to a free radical generator causing an oxidative stress, 90% cell death was measured in CON serum treated cultures, while ACC serum treated cultures were neuroprotected. Xanthine oxidase activity and uric acid (UA) levels were lower in ACC serum compared to CON. Addition of UA to both sera abolished the difference in cell viability, and toxicity of ACC serum reached that of CON. These findings suggest a causal relationship between the lower levels of UA in ACC and the neuroprotective effect observed. The present study proposes heat acclimation as an experimental and/or clinical tool for the achievement of neuroprotection.

Effect of short-term heat acclimation on endurance time and skin blood flow in trained athletes

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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

Resting energy expenditure of rats acclimated to hypergravity

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Wade, Charles E.; Moran, Megan M.; Oyama, Jiro

2002-01-01

BACKGROUND: The use of centrifugation at 1 G has been advocated as a control condition during spaceflight and as a countermeasure to compensate for the adverse effects of spaceflight. Rodents are the primary animal model for the study of the effects of spaceflight and will be used in the evaluation of centrifugation as a countermeasure and means of control at 1 G during flight. HYPOTHESIS: The present study was designed to assess whether resting energy expenditure (EER) of male rats was increased in relation to the magnitude of the level of gravity to which the animals were exposed. The influence of body mass and age on resting energy expenditure (EER) of male rats (n = 42, age 40-400 d) was determined following 2 wk of acclimation to 1, 2.3, or 4.1 G. Hypergravity environments were created by centrifugation. Measurements were made at the gravity level to which the animal was acclimated and during the lights-on period. RESULTS: In rats matched for body mass (approximately 400 g), mean O2 consumption and CO2 production were higher (18% and 27%, respectively) in the 2.3- and 4.1 -G groups than controls. Mean respiratory exchange ratio (RER) increased from 0.80 to 0.87. EER was increased from 47 +/- 0.1 kcal x d(-1) at 1 G, to 57 +/- 1.5 and 58 +/- 2.2 kcal x d(-1) at 2.3 and 4.1 G, respectively. There was no difference in EER between the hypergravity groups. When age differences were considered, EER (kcal x kg(-1) x d(-1)) with increased gravity was 40% higher than at 1 G. The increase in EER was not proportional over gravity levels. CONCLUSION: Acclimation of rats to hypergravity increases their EER, dependent on body mass and age, and may alter substrate metabolism. The increase in EER was not related to the level of gravity increase.

Ice Nucleation, Propagation, and Deep Supercooling: The Lost Tribes of Freezing Studies

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The past twenty years has seen an explosion of research in trying to identify genes involved in cold acclimation. Hundreds of genes are affected by exposure to low temperature but studies have mainly focused on genes that provide cryoprotection or tolerance to dehydrative stress. Some of the genes...

Acclimation of methane production weakens ecosystem response to climate warming in a northern peatland

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MA, S.; Huang, Y.; Jiang, J.; Ricciuto, D. M.; Hanson, P. J.; Luo, Y.

2017-12-01

Warming-induced increases in greenhouse gases from terrestrial ecosystems represent a positive feedback to twenty-first-century climate warming, but the magnitude of this stimulatory effect remains uncertain. Acclimation of soil respiration and photosynthesis have been found to slow down the feedback due to the substrate limitation and thermal adaptation. However, acclimation of ecosystem methane emission to climate warming has not been well illustrated, despite that methane is directly responsible for approximately 20% of global warming since pre-industrial time. In this study, we used the data-model fusion approach to explore the potential acclimation of methane emission to climate warming. We assimilated CH4 static chamber flux data at the Spruce and Peatland Responses Under Climatic and Environmental Change (SPRUCE) experimental site into the ecosystem model, TECO_SPRUCE. The SPRUCE project has been conducted to study the responses of northern peatland to climate warming (+0, +2.25, +4.5, +6.75, +9 °C) and elevated atmospheric CO2 concentration (+0 and +500 ppm). The warming treatments were initiated from June 2014. We estimated parameter values using environmental and flux data in those five warming treatment levels from 2014 to 2016 for the acclimation study. The key parameters that were estimated for methane emissions are the potential ratio of CO2 converted to CH4 (r_me), Q10 for CH4 production (Q10_pro), maximum oxidation rate (Omax) and the factor of transport ability at plant community level (Tveg). Among them, r_me and Q10_pro were well constrained in each treatment plot. Q10 decreased from 3.33 (control) to 1.22 (+9˚C treatment) and r_me decreased from 0.675 (control) to 0.505 (+9˚C treatment). The acclimation will dampen the warming effect on methane production and emission. Current ecosystem models assumed constant Q10 for CH4 production and CH4/CO2 conversion ratio in the future warmed climate. The assumption is likely to overestimate the methane

The Arabidopsis mediator complex subunits MED16, MED14, and MED2 regulate mediator and RNA polymerase II recruitment to CBF-responsive cold-regulated genes.

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Hemsley, Piers A; Hurst, Charlotte H; Kaliyadasa, Ewon; Lamb, Rebecca; Knight, Marc R; De Cothi, Elizabeth A; Steele, John F; Knight, Heather

2014-01-01

The Mediator16 (MED16; formerly termed SENSITIVE TO FREEZING6 [SFR6]) subunit of the plant Mediator transcriptional coactivator complex regulates cold-responsive gene expression in Arabidopsis thaliana, acting downstream of the C-repeat binding factor (CBF) transcription factors to recruit the core Mediator complex to cold-regulated genes. Here, we use loss-of-function mutants to show that RNA polymerase II recruitment to CBF-responsive cold-regulated genes requires MED16, MED2, and MED14 subunits. Transcription of genes known to be regulated via CBFs binding to the C-repeat motif/drought-responsive element promoter motif requires all three Mediator subunits, as does cold acclimation-induced freezing tolerance. In addition, these three subunits are required for low temperature-induced expression of some other, but not all, cold-responsive genes, including genes that are not known targets of CBFs. Genes inducible by darkness also required MED16 but required a different combination of Mediator subunits for their expression than the genes induced by cold. Together, our data illustrate that plants control transcription of specific genes through the action of subsets of Mediator subunits; the specific combination defined by the nature of the stimulus but also by the identity of the gene induced.

Analysis of cold resistance and identification of SSR markers linked to cold resistance genes in Brassica rapa L.

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Huang, Zhen; Zhang, Xuexian; Jiang, Shouhua; Qin, Mengfan; Zhao, Na; Lang, Lina; Liu, Yaping; Tian, Zhengshu; Liu, Xia; Wang, Yang; Zhang, Binbin; Xu, Aixia

2017-06-01

Currently, cold temperatures are one of the main factors threatening rapeseed production worldwide; thus, it is imperative to identify cold-resistant germplasm and to cultivate cold-resistant rapeseed varieties. In this study, the cold resistance of four Brassica rapa varieties was analyzed. The cold resistance of Longyou6 and Longyou7 was better than that of Tianyou2 and Tianyou4. Thus, an F 2 population derived from Longyou6 and Tianyou4 was used to study the correlation of cold resistance and physiological indexes. Our results showed that the degree of frost damage was related to the relative conductivity and MDA content (r1 = 0.558 and r2 = 0.447, respectively). In order to identify the markers related to cold resistance, 504 pairs of SSR (simple sequence repeats) primers were used to screen the two parents and F 2 population. Four and five SSR markers had highly significant positive correlation to relative conductivity and MDA, respectively. In addition, three of these SSR markers had a highly significant positive correlation to both of these two indexes. These three SSR markers were subsequently confirmed to be used to distinguish between cold-resistant and non-cold-resistant varieties. The results of this study will lay a solid foundation for the mapping of cold-resistant genes and molecular markers assisted selection for the cold-resistance.

Gradual plasticity alters population dynamics in variable environments: thermal acclimation in the green alga Chlamydomonas reinhartdii.

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Kremer, Colin T; Fey, Samuel B; Arellano, Aldo A; Vasseur, David A

2018-01-10

Environmental variability is ubiquitous, but its effects on populations are not fully understood or predictable. Recent attention has focused on how rapid evolution can impact ecological dynamics via adaptive trait change. However, the impact of trait change arising from plastic responses has received less attention, and is often assumed to optimize performance and unfold on a separate, faster timescale than ecological dynamics. Challenging these assumptions, we propose that gradual plasticity is important for ecological dynamics, and present a study of the plastic responses of the freshwater green algae Chlamydomonas reinhardtii as it acclimates to temperature changes. First, we show that C. reinhardtii 's gradual acclimation responses can both enhance and suppress its performance after a perturbation, depending on its prior thermal history. Second, we demonstrate that where conventional approaches fail to predict the population dynamics of C. reinhardtii exposed to temperature fluctuations, a new model of gradual acclimation succeeds. Finally, using high-resolution data, we show that phytoplankton in lake ecosystems can experience thermal variation sufficient to make acclimation relevant. These results challenge prevailing assumptions about plasticity's interactions with ecological dynamics. Amidst the current emphasis on rapid evolution, it is critical that we also develop predictive methods accounting for plasticity. © 2018 The Author(s).

Higher acclimation temperature modulates the composition of muscle fatty acid of Tor putitora juveniles

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M.S. Akhtar

2014-08-01

Full Text Available A 30-day acclimation trial was conducted using golden mahseer, Tor putitora juveniles to study its muscle fatty acid composition at five acclimation temperatures (AT. Ninety juveniles of T. putitora were distributed among five treatment groups (20, 23, 26, 29 and 32±0.5 °C. At the end of 30 days trial, highest percentage of monounsaturated fatty acids was found at 20 °C and lowest at 26 °C. The highest percentage of n-6 polyunsaturated fatty acid (PUFA was found at 23 °C and a decreasing trend was observed with increase in AT. However, highest percentage of n-3 PUFA was found at 32 °C and lowest at 29 °C. The maximum n-6 to n-3 ratio was observed at 23 °C and ratio decreased to a minimum at 32 °C. The results revealed that T. putitora juveniles could adapt to higher acclimation temperatures by altering its muscle fatty acid composition mainly by increasing its total saturated fatty acids especially stearic acid.

Influence of acclimation to sublethal temperature on heat tolerance of Tribolium castaneum (Herbst (Coleoptera: Tenebrionidae exposed to 50°C.

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Jianhua Lü

Full Text Available Tribolium castaneum (Herbst (Coleoptera: Tenebrionidae is a serious pest of stored agricultural products and one of the most common insects found in grain storage and food processing facilities. Heat treatment has been revisited to control stored-product insects as a potential alternative to methyl bromide for disinfesting mills and food-processing facilities. The influence of acclimation of T. castaneum adults, pupae, larvae, and eggs to sublethal temperatures of 36, and 42°C on their subsequent susceptibility to lethal temperature of 50°C was respectively investigated. The acclimation of T. castaneum eggs, larvae, pupae, and adults to 36, and 42°C significantly decreased their subsequent susceptibility to lethal high temperature of 50°C. The influence of acclimation to 42°C was significantly greater than that of acclimation to 36°C. The most influential acclimation times at 42°C for mortality of T. castaneum eggs, larvae, pupae, and adults were 15, 5, 5, and 5 h, respectively, and their corresponding mortality were 41.24, 5.59, 20.19, and 4.48%, compared to 100% mortality of T. castaneum eggs, larvae, pupae, and adults without acclimation when exposed to 50°C for 35 min, respectively. The present results have important implications for developing successful heat treatment protocols to control T. castaneum, improving disinfestation effectiveness of heat treatment and understanding insect response to high temperatures.

Social science in the Cold War.

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Engerman, David C

2010-06-01

This essay examines ways in which American social science in the late twentieth century was--and was not--a creature of the Cold War. It identifies important work by historians that calls into question the assumption that all social science during the Cold War amounts to "Cold War social science." These historians attribute significant agency to social scientists, showing how they were enmeshed in both long-running disciplinary discussions and new institutional environments. Key trends in this scholarship include a broadening historical perspective to see social scientists in the Cold War as responding to the ideas of their scholarly predecessors; identifying the institutional legacies of World War II; and examining in close detail the products of extramural--especially governmental--funding. The result is a view of social science in the Cold War in which national security concerns are relevant, but with varied and often unexpected impacts on intellectual life.

A bulk segregant gene expression analysis of a peach population reveals components of the underlying mechanism of the fruit cold response.

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Clara Pons

Full Text Available Peach fruits subjected for long periods of cold storage are primed to develop chilling injury once fruits are shelf ripened at room temperature. Very little is known about the molecular changes occurring in fruits during cold exposure. To get some insight into this process a transcript profiling analyses was performed on fruits from a PopDG population segregating for chilling injury CI responses. A bulked segregant gene expression analysis based on groups of fruits showing extreme CI responses indicated that the transcriptome of peach fruits was modified already during cold storage consistently with eventual CI development. Most peach cold-responsive genes have orthologs in Arabidopsis that participate in cold acclimation and other stresses responses, while some of them showed expression patterns that differs in fruits according to their susceptibility to develop mealiness. Members of ICE1, CBF1/3 and HOS9 regulons seem to have a prominent role in differential cold responses between low and high sensitive fruits. In high sensitive fruits, an alternative cold response program is detected. This program is probably associated with dehydration/osmotic stress and regulated by ABA, auxins and ethylene. In addition, the observation that tolerant siblings showed a series of genes encoding for stress protective activities with higher expression both at harvest and during cold treatment, suggests that preprogrammed mechanisms could shape fruit ability to tolerate postharvest cold-induced stress. A number of genes differentially expressed were validated and extended to individual genotypes by medium-throughput RT-qPCR. Analyses presented here provide a global view of the responses of peach fruits to cold storage and highlights new peach genes that probably play important roles in the tolerance/sensitivity to cold storage. Our results provide a roadmap for further experiments and would help to develop new postharvest protocols and gene directed breeding

A bulk segregant gene expression analysis of a peach population reveals components of the underlying mechanism of the fruit cold response.

Science.gov (United States)

Pons, Clara; Martí, Cristina; Forment, Javier; Crisosto, Carlos H; Dandekar, Abhaya M; Granell, Antonio

2014-01-01

Peach fruits subjected for long periods of cold storage are primed to develop chilling injury once fruits are shelf ripened at room temperature. Very little is known about the molecular changes occurring in fruits during cold exposure. To get some insight into this process a transcript profiling analyses was performed on fruits from a PopDG population segregating for chilling injury CI responses. A bulked segregant gene expression analysis based on groups of fruits showing extreme CI responses indicated that the transcriptome of peach fruits was modified already during cold storage consistently with eventual CI development. Most peach cold-responsive genes have orthologs in Arabidopsis that participate in cold acclimation and other stresses responses, while some of them showed expression patterns that differs in fruits according to their susceptibility to develop mealiness. Members of ICE1, CBF1/3 and HOS9 regulons seem to have a prominent role in differential cold responses between low and high sensitive fruits. In high sensitive fruits, an alternative cold response program is detected. This program is probably associated with dehydration/osmotic stress and regulated by ABA, auxins and ethylene. In addition, the observation that tolerant siblings showed a series of genes encoding for stress protective activities with higher expression both at harvest and during cold treatment, suggests that preprogrammed mechanisms could shape fruit ability to tolerate postharvest cold-induced stress. A number of genes differentially expressed were validated and extended to individual genotypes by medium-throughput RT-qPCR. Analyses presented here provide a global view of the responses of peach fruits to cold storage and highlights new peach genes that probably play important roles in the tolerance/sensitivity to cold storage. Our results provide a roadmap for further experiments and would help to develop new postharvest protocols and gene directed breeding strategies to better

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

Functional evolution of leptin of Ochotona curzoniae in adaptive thermogenesis driven by cold environmental stress.

Directory of Open Access Journals (Sweden)

Jie Yang

Full Text Available BACKGROUND: Environmental stress can accelerate the directional selection and evolutionary rate of specific stress-response proteins to bring about new or altered functions, enhancing an organism's fitness to challenging environments. Plateau pika (Ochotona curzoniae, an endemic and keystone species on Qinghai-Tibetan Plateau, is a high hypoxia and low temperature tolerant mammal with high resting metabolic rate and non-shivering thermogenesis to cope in this harsh plateau environment. Leptin is a key hormone related to how these animals regulate energy homeostasis. Previous molecular evolutionary analysis helped to generate the hypothesis that adaptive evolution of plateau pika leptin may be driven by cold stress. METHODOLOGY/PRINCIPAL FINDINGS: To test the hypothesis, recombinant pika leptin was first purified. The thermogenic characteristics of C57BL/6J mice injected with pika leptin under warm (23±1°C and cold (5±1°C acclimation is investigated. Expression levels of genes regulating adaptive thermogenesis in brown adipose tissue and the hypothalamus are compared between pika leptin and human leptin treatment, suggesting that pika leptin has adaptively and functionally evolved. Our results show that pika leptin regulates energy homeostasis via reduced food intake and increased energy expenditure under both warm and cold conditions. Compared with human leptin, pika leptin demonstrates a superior induced capacity for adaptive thermogenesis, which is reflected in a more enhanced β-oxidation, mitochondrial biogenesis and heat production. Moreover, leptin treatment combined with cold stimulation has a significant synergistic effect on adaptive thermogenesis, more so than is observed with a single cold exposure or single leptin treatment. CONCLUSIONS/SIGNIFICANCE: These findings support the hypothesis that cold stress has driven the functional evolution of plateau pika leptin as an ecological adaptation to the Qinghai-Tibetan Plateau.

Working in the Cold

Centers for Disease Control (CDC) Podcasts

2016-02-08

During the winter, many workers are outdoors, working in cold, wet, icy, or snowy conditions. Learn how to identify symptoms that tell you there may be a problem and protect yourself from cold stress.  Created: 2/8/2016 by National Institute for Occupational Safety and Health (NIOSH).   Date Released: 2/8/2016.

Acclimation of Juglans mandshurica Maxim. and Phellodendron amurense Rupr. in the Middle Volga region

Science.gov (United States)

Tishin, D.; Fardeeva, M.; Chizhikova, N.; Rizatdinov, R.

2018-01-01

This research is the first attempt to analyze the results of acclimation of J. mandshurica and P. amurense in coniferous-deciduous forests under the conditions of the temperate continental climate of the Middle Volga Region. The study has been performed in the Volga-Kama Nature Reserve (Republic of Tatarstan, Russia) and demonstrated that J. mandshurica is a successfully acclimated species. This species naturalized in the forests of the Reserve, being distinguished by a rapid biomass production, high germination capacity of seeds and high number of pre-generative specimens. P. amurense can be characterized by the opposite features.

Increased temperature tolerance of the air-breathing Asian swamp eel Monopterus albus after high-temperature acclimation is not explained by improved cardiorespiratory performance.

Science.gov (United States)

Lefevre, S; Findorf, I; Bayley, M; Huong, D T T; Wang, T

2016-01-01

This study investigated the hypothesis that in the Asian swamp eel Monopterus albus, an air-breathing fish from south-east Asia that uses the buccopharyngeal cavity for oxygen uptake, the upper critical temperature (TU) is increased by acclimation to higher temperature, and that the increased TU is associated with improved cardiovascular and respiratory function. Monopterus albus were therefore acclimated to 27° C (current average) and 32° C (current maximum temperature as well as projected average within 100-200 years), and both the effect of acclimation and acute temperature increments on cardiovascular and respiratory functions were investigated. Two weeks of heat acclimation increased upper tolerated temperature (TU ) by 2° C from 36·9 ± 0·1° C to 38·9 ± 0·1° C (mean ± s.e.). Oxygen uptake (M˙O2) increased with acclimation temperature, accommodated by increases in both aerial and aquatic respiration. Overall, M˙O2 from air (M˙O2a ) was predominant, representing 85% in 27° C acclimated fish and 80% in 32° C acclimated fish. M˙O2 increased with acute increments in temperature and this increase was entirely accommodated by an increase in air-breathing frequency and M˙O2a . Monopterus albus failed to upregulate stroke volume; rather, cardiac output was maintained through increased heart rate with rising temperature. Overall, acclimation of M. albus to 32° C did not improve its cardiovascular and respiratory performance at higher temperatures, and cardiovascular adaptations, therefore, do not appear to contribute to the observed increase in TU. © 2015 The Fisheries Society of the British Isles.

Monitoring the vaccine cold chain.

OpenAIRE

Cheriyan, E

1993-01-01

Maintaining the vaccine cold chain is an essential part of a successful immunisation programme. A continuous electronic temperature monitor helped to identify breaks in the cold chain in the community and the study led to the issue of proper guidelines and replacement of faulty equipment.

Enhanced ethanol production by fermentation of Gelidium amansii hydrolysate using a detoxification process and yeasts acclimated to high-salt concentration.

Science.gov (United States)

Ra, Chae Hun; Jung, Jang Hyun; Sunwoo, In Yung; Jeong, Gwi-Taek; Kim, Sung-Koo

2015-06-01

A total monosaccharide concentration of 59.0 g/L, representing 80.1 % conversion of 73.6 g/L total fermentable sugars from 160 g dw/L G. amansii slurry was obtained by thermal acid hydrolysis and enzymatic hydrolysis. Subsequent adsorption treatment using 5 % activated carbon with an adsorption time of 2 min was used to prevent the inhibitory effect of 5-hydroxymethylfurfural (HMF) >5 g/L in the medium. Ethanol production decreased with increasing salt concentration using C. tropicalis KCTC 7212 non-acclimated or acclimated to a high concentration of salt. Salt concentration of 90 psu was the maximum concentration for cell growth and ethanol production. The levels of ethanol production by C. tropicalis non-acclimated or acclimated to 90 psu high-salt concentration were 13.8 g/L with a yield (YEtOH) of 0.23, and 26.7 g/L with YEtOH of 0.45, respectively.

Thermal Acclimation of Photosynthesis and Respiration Differ Across Mature Conifer Species in a Boreal Forest Peatland

Science.gov (United States)

Dusenge, M. E.; Stinziano, J. R.; Warren, J.; Ward, E. J.; Wullschleger, S.; Hanson, P. J.; Way, D.

2017-12-01

Boreal forests are often assumed to be temperature-limited, and warming is therefore expected to stimulate their carbon uptake. However, much of our information on the ability of boreal conifers to acclimate photosynthesis and respiration to rising temperatures comes from seedlings. We measured net CO2 assimilation rates (A) and dark respiration (R) at 25 °C (A25 and R25) and at prevailing growth temperatures (Ag and Rg) in mature Picea mariana (spruce) and Larix laricina (tamarack) exposed to ambient, +2.25, +4.5, +6.75 and +9 °C warming treatments in open top chambers in the field at the SPRUCE experiment (MN, USA). In spruce, A25 and Ag were similar across plots in May and June. In August, spruce in warmer treatments had higher A25, an effect that was offset by warmer leaf temperatures in the Ag data. In tamarack, A25 was stimulated by warming in both June and August, an effect that was mainly offset by higher leaf temperatures when Ag was assessed in June, while in August, Ag was still slightly higher in the warmest treatments (+6.75 and +9) compared to the ambient plots. In spruce, R25 was enhanced in warm-grown trees in May, but was similar across treatments in June and August, indicating little acclimation of R. Rg slightly increased with warming treatments across the season in spruce. In contrast, R in tamarack thermally acclimated, as R25 decreased with warming. But while this acclimation generated homeostatic Rg in June, Rg in August was still highest in the warmest treatments. Our work suggests that the capacity for thermal acclimation in both photosynthesis and respiration varies among boreal tree species, which may lead to shifts in the performance of these species as the climate warms.

Comparing Enchytraeus albidus populations from contrasting climatic environments suggest a link between cold tolerance and metabolic activity.

Science.gov (United States)

Žagar, Anamarija; Holmstrup, Martin; Simčič, Tatjana; Debeljak, Barabara; Slotsbo, Stine

2018-06-06

Basal metabolic activity and freezing of body fluids create reactive oxygen species (ROS) in freeze-tolerant organisms. These sources of ROS can have an additive negative effect via oxidative stress. In cells, antioxidant systems are responsible for removing ROS in order to avoid damage due to oxidative stress. Relatively little is known about the importance of metabolic rate for the survival of freezing, despite a good understanding of several cold tolerance related physiological mechanisms. We hypothesized that low basal metabolism would be selected for in freeze-tolerant organisms where winter survival is important for fitness for two reasons. First, avoidance of the additive effect of ROS production from metabolism and freezing, and second, as an energy-saving mechanism under extended periods of freezing where the animal is metabolically active, but unable to feed. We used the terrestrial oligochaete, Enchytraeus albidus, which is widely distributed from Spain to the high Arctic and compared eight populations originating across a broad geographical and climatic gradient after they had been cold acclimated at 5 °C in a common garden experiment. Cold tolerance (lower lethal temperature: LT50) and the potential metabolic activity (PMA, an estimator of the maximal enzymatic potential of the mitochondrial respiration chain) of eight populations were positively correlated amongst each other and correlated negatively with latitude and positively with average yearly temperature and the average temperature of the coldest month. These results indicate that low PMA in cold tolerant populations is important for survival in extremely cold environments. Copyright © 2018. Published by Elsevier Inc.

Acclimation strategy of Rhodopseudomonas palustris to high light irradiance.

Science.gov (United States)

Muzziotti, Dayana; Adessi, Alessandra; Faraloni, Cecilia; Torzillo, Giuseppe; De Philippis, Roberto

2017-04-01

The ability of Rhodopseudomonas palustris cells to rapidly acclimate to high light irradiance is an essential issue when cells are grown under sunlight. The aim of this study was to investigate the photo-acclimation process in Rhodopseudomonas palustris 42OL under different culturing conditions: (i) anaerobic (AnG), (ii) aerobic (AG), and (iii) under H 2 -producing (HP) conditions both at low (LL) and high light (HL) irradiances. The results obtained clearly showed that the photosynthetic unit was significantly affected by the light irradiance at which Rp. palustris 42OL was grown. The synthesis of carotenoids was affected by both illumination and culturing conditions. At LL, lycopene was the main carotenoid synthetized under all conditions tested, while at HL under HP conditions, it resulted the predominant carotenoid. Oppositely, under AnG and AG at HL, rhodovibrin was the major carotenoid detected. The increase in light intensity produced a deeper variation in light-harvesting complexes (LHC) ratio. These findings are important for understanding the ecological distribution of PNSB in natural environments, mostly characterized by high light intensities, and for its growth outdoors. Copyright © 2017 Elsevier GmbH. All rights reserved.

Acclimation of photosynthetic capacity to irradiance in tree canopies in relation to leaf nitrogen concentration and leaf mass per unit area

NARCIS (Netherlands)

Meir, P.; Kruijt, B.; Broadmeadow, M.; Barbosa, E.; Kull, O.; Carswell, F.; Nobre, A.; Jarvis, P.G.

2002-01-01

The observation of acclimation in leaf photosynthetic capacity to differences in growth irradiance has been widely used as support for a hypothesis that enables a simplification of some soil-vegetation-atmosphere transfer (SVAT) photosynthesis models. The acclimation hypothesis requires that

Hand immersion in cold water alleviating physiological strain and increasing tolerance to uncompensable heat stress.

Science.gov (United States)

Khomenok, Gennadi A; Hadid, Amir; Preiss-Bloom, Orahn; Yanovich, Ran; Erlich, Tomer; Ron-Tal, Osnat; Peled, Amir; Epstein, Yoram; Moran, Daniel S

2008-09-01

The current study examines the use of hand immersion in cold water to alleviate physiological strain caused by exercising in a hot climate while wearing NBC protective garments. Seventeen heat acclimated subjects wearing a semi-permeable NBC protective garment and a light bulletproof vest were exposed to a 125 min exercise-heat stress (35 degrees C, 50% RH; 5 km/h, 5% incline). The heat stress exposure routine included 5 min rest in the chamber followed by two 50:10 min work-rest cycles. During the control trial (CO), there was no intervention, whilst in the intervention condition the subjects immersed their hands and forearms in a 10 degrees C water bath (HI). The results demonstrated that hand immersion in cold water significantly reduced physiological strain. In the CO exposure during the first and second resting periods, the average rectal temperature (T (re)) practically did not decrease. With hand immersion, the mean (SD) T (re) decreased by 0.45 (0.05 degrees C) and 0.48 degrees C (0.06 degrees C) during the first and second rest periods respectively (P immersion in cold water for 10 min is an effective method for decreasing the physiological strain caused by exercising under heat stress while wearing NBC protective garments. The method is convenient, simple, and allows longer working periods in hot or contaminated areas with shorter resting periods.

Freshwater to seawater acclimation of juvenile bull sharks (Carcharhinus leucas): plasma osmolytes and Na+/K+-ATPase activity in gill, rectal gland, kidney and intestine.

Science.gov (United States)

Pillans, Richard D; Good, Jonathan P; Anderson, W Gary; Hazon, Neil; Franklin, Craig E

2005-01-01

This study examined the osmoregulatory status of the euryhaline elasmobranch Carcharhinus leucas acclimated to freshwater (FW) and seawater (SW). Juvenile C. leucas captured in FW (3 mOsm l(-1) kg(-1)) were acclimated to SW (980-1,000 mOsm l(-1) kg(-1)) over 16 days. A FW group was maintained in captivity over a similar time period. In FW, bull sharks were hyper-osmotic regulators, having a plasma osmolarity of 595 mOsm l(-1) kg(-1). In SW, bull sharks had significantly higher plasma osmolarities (940 mOsm l(-1) kg(-1)) than FW-acclimated animals and were slightly hypo-osmotic to the environment. Plasma Na(+), Cl(-), K(+), Mg(2+), Ca(2+), urea and trimethylamine oxide (TMAO) concentrations were all significantly higher in bull sharks acclimated to SW, with urea and TMAO showing the greatest increase. Gill, rectal gland, kidney and intestinal tissue were taken from animals acclimated to FW and SW and analysed for maximal Na(+)/K(+)-ATPase activity. Na(+)/K(+)-ATPase activity in the gills and intestine was less than 1 mmol Pi mg(-1) protein h(-1) and there was no difference in activity between FW- and SW-acclimated animals. In contrast Na(+)/K(+)-ATPase activity in the rectal gland and kidney were significantly higher than gill and intestine and showed significant differences between the FW- and SW-acclimated groups. In FW and SW, rectal gland Na(+)/K(+)-ATPase activity was 5.6+/-0.8 and 9.2+/-0.6 mmol Pi mg(-1) protein h(-1), respectively. Na(+)/K(+)-ATPase activity in the kidney of FW and SW acclimated animals was 8.4+/-1.1 and 3.3+/-1.1 Pi mg(-1) protein h(-1), respectively. Thus juvenile bull sharks have the osmoregulatory plasticity to acclimate to SW; their preference for the upper reaches of rivers where salinity is low is therefore likely to be for predator avoidance and/or increased food abundance rather than because of a physiological constraint.

Molecular characterization of three Hsp90 from Pieris and expression patterns in response to cold and thermal stress in summer and winter diapause of Pieris melete.

Science.gov (United States)

Wu, Yue-Kun; Zou, Chao; Fu, Dao-Meng; Zhang, Wan-Na; Xiao, Hai-Jun

2018-04-01

Heat shock proteins (Hsps) have been linked to stresses and winter diapause in insects, but whether they are components of summer diapause is still unknown. In this study, complementary DNAs of Hsp90 from Pieris melete, Pieris rapae and Pieris canidia named PmHsp90, PrHsp90 and PcHsp90, respectively, were cloned and sequenced. The deduced amino acid sequence consisted of 718 amino acid residues with a putative molecular mass of 82.6, 82.6 and 82.7 kDa, respectively. The amino acid sequences contained all of the five conserved signature motifs in the Hsp90 family and a bHLH protein folding activity region. The differential expression pattern of PmHsp90 in response to summer diapause and winter diapause, which are related to heat/cold stress, was investigated. Cold stress induced Hsp90 up-regulation in summer and winter diapause pupae, but not in non-diapause individuals. Heat shock up-regulated PmHsp90 gradually with an increase in temperature in summer diapause, and PmHsp90 was rapidly up-regulated in winter diapause. After 30 min heat shock at 39°C, substantial up-regulation of PmHsp90 transcript levels were observed both in summer and winter diapause. However, in non-diapause a relatively stable expression was found under different durations of 39°C heat shock. Compared to the optimal treatment of 18°C for diapause development, a high temperature acclimation of 31°C induced PmHsp90 up-regulation in summer diapause, whereas a low temperature acclimation of 4°C induced up-regulation in winter diapause. The current results indicate that Hsp90 may play an important role in response to heat/cold stress both in summer and winter diapause. © 2016 Institute of Zoology, Chinese Academy of Sciences.

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.

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...

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

Extraction of items identifying hiesho (cold disorder) and their utility in young males and females.

Science.gov (United States)

Sakaguchi, Shunji; Kuge, Hiroshi; Mori, Hidetoshi; Miyazaki, Junji; Tanaka, Tim Hideaki; Hanyu, Kazuyo; Takeda, Taro; Sasaki, Kazuro

2016-01-01

Hie (cold sensation) is one of the most common health complaints in Japan. Those who suffer from severe hie are considered as having hiesho (cold disorder). However, exact hiesho symptoms have not been defined clearly and the decision as to whether a person suffers from hiesho is subjective and based on self-awareness. The study was conducted in attempt to develop a standardized hiesho diagnostic scale. Subjects comprised 1 146 students. From the self-awareness of hiesho symptoms, males and females were divided into hiesho and non-hiesho groups. Physical, behavioral and adaptive characteristics were compared using the 24-item questionnaire (four-grade survey) and indicators for hiesho symptoms were extracted. Based on the scores, a receiver operating characteristic curve was drawn for the total ordinal scale score of the extracted items in relation to the presence and absence of hiesho symptoms, and an optimal cutoff value was determined. The self-awareness of having hiesho was found in 23.2% males and in 55.6% females. The sensitivity was 84.5% for males and 83.3% for females in the hiesho groups, and the specificity was 86.0% for males and 85.2% for females in the non-hiesho groups. A questionnaire consisting of the extracted items may be useful to identify hiesho in young males and females with a high level of accuracy.

Acclimation of juvenile Mugil liza Valenciennes, 1836 (Mugiliformes: Mugilidae to different environmental salinities

Directory of Open Access Journals (Sweden)

Viviana Lisboa

Full Text Available Survival and physiological parameters associated with metabolism and osmoregulation were evaluated in juveniles of the Lebranche mullet Mugil liza acclimated to different water salinities (5, 10, 20, 30, and 40‰ for 15 days. Room temperature (25ºC and photoperiod (12L:12D were fixed. Fish were fed twice-a-day with commercial diet (28% crude protein until satiation. After acclimation, whole body oxygen consumption was measured and fish were euthanized and sampled for blood, gills, and liver. Whole body oxygen consumption and plasma osmolality did not change in the range of salinities tested. The isosmotic point was estimated as 412.7 mOsmol kg-1 (13.5‰. Gill Na+,K+-ATPase activity tended to be lower at 20 and 30‰, while liver glycogen content was significantly higher at 20‰ than at 5 and 40‰. These results indicate that juvenile M. liza is able to acclimate for a short-period of time (15 days to a wide range of salinities (5-40‰. This condition is achieved through adjustments in gill Na+,K+-ATPase activity and carbohydrate metabolism to regulate plasma osmolality and aerobic/energy metabolism. Therefore, our findings support the idea of catching juveniles M. liza in sea water and rear them in estuarine and marine waters.

Data on the density of xanthophores in a whole scale of goldfish acclimated to white or black background color

Directory of Open Access Journals (Sweden)

Kanta Mizusawa

2017-10-01

Full Text Available The data presented in this article are related to the research article entitled “Expression of genes for melanotropic peptides and their receptors for morphological color change in goldfish Carassius auratus” (Mizusawa et al., In press [1]. This article describes data on the density of xanthophores in the scales of goldfish acclimated to white or black background color. To determine the effects of acclimation history during long-term background color adaptation, fish were transferred from a white tank to a white or black tank and vice versa halfway through the acclimation process. To observe xanthophores, the iridophore layer was scraped from the scale and the pteridine/carotenoid pigments were aggregated. The number of xanthophores was calculated after image processing.

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.

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

2018-01-01

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...... 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...

Cold thermal injury from cold caps used for the prevention of chemotherapy-induced alopecia.

Science.gov (United States)

Belum, Viswanath Reddy; de Barros Silva, Giselle; Laloni, Mariana Tosello; Ciccolini, Kathryn; Goldfarb, Shari B; Norton, Larry; Sklarin, Nancy T; Lacouture, Mario E

2016-06-01

The use of scalp cooling for the prevention of chemotherapy-induced alopecia (CIA) is increasing. Cold caps are placed onto the hair-bearing areas of the scalp for varying time periods before, during, and after cytotoxic chemotherapy. Although not yet reported, improper application procedures could result in adverse events (AEs). At present, there are no evidence-based scalp cooling protocols, and there is no regulatory oversight of their use. To report the occurrence of cold thermal injury (frostbite) on the scalp, following the use of cold caps for the prevention of CIA. We identified four patients who developed cold thermal injuries on the scalp following the application of cold caps. Medical records were analyzed to retrieve the demographic and clinical characteristics. The cold thermal injuries in our patients were grade 1/2 in severity and improved with topical interventions and interruption of cold cap use, although grade 1 persistent alopecia ensued in 3 patients. The true incidence of such injuries in this setting, however, remains unknown. Cold thermal injuries are likely infrequent and preventable AEs that may result from improper device application procedures during cold cap use. Although these untoward events are usually mild to moderate in severity, the potential occurrence of long-term sequelae (e.g., permanent alopecia and scarring) or the need to discontinue cold cap use, are not known. Prospective studies are needed to further elucidate the risk and standardize healthcare delivery methods, and to improve patient/supportive/healthcare provider education.

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.

Metabolic acclimation to excess light intensity in Chlamydomonas reinhardtii.

Science.gov (United States)

Davis, Maria C; Fiehn, Oliver; Durnford, Dion G

2013-07-01

There are several well-described acclimation responses to excess light in green algae but the effect on metabolism has not been thoroughly investigated. This study examines the metabolic changes during photoacclimation to high-light (HL) stress in Chlamydomonas reinhardtii using nuclear magnetic resonance and mass spectrometry. Using principal component analysis, a clear metabolic response to HL intensity was observed on global metabolite pools, with major changes in the levels of amino acids and related nitrogen metabolites. Amino acid pools increased during short-term photoacclimation, but were especially prominent in HL-acclimated cultures. Unexpectedly, we observed an increase in mitochondrial metabolism through downstream photorespiratory pathways. The expression of two genes encoding key enzymes in the photorespiratory pathway, glycolate dehydrogenase and malate synthase, were highly responsive to the HL stress. We propose that this pathway contributes to metabolite pools involved in nitrogen assimilation and may play a direct role in photoacclimation. Our results suggest that primary and secondary metabolism is highly pliable and plays a critical role in coping with the energetic imbalance during HL exposure and a necessary adjustment to support an increased growth rate that is an effective energy sink for the excess reducing power generated during HL stress. © 2013 John Wiley & Sons Ltd.

Acclimation of Swedish and Italian ecotypes of Arabidopsis thaliana to light intensity.

Science.gov (United States)

Stewart, Jared J; Polutchko, Stephanie K; Adams, William W; Demmig-Adams, Barbara

2017-11-01

This study addressed whether ecotypes of Arabidopsis thaliana from Sweden and Italy exhibited differences in foliar acclimation to high versus low growth light intensity, and compared CO 2 uptake under growth conditions with light- and CO 2 -saturated intrinsic photosynthetic capacity and leaf morphological and vascular features. Differential responses between ecotypes occurred mainly at the scale of leaf architecture, with thicker leaves with higher intrinsic photosynthetic capacities and chlorophyll contents per leaf area, but no difference in photosynthetic capacity on a chlorophyll basis, in high light-grown leaves of the Swedish versus the Italian ecotype. Greater intrinsic photosynthetic capacity per leaf area in the Swedish ecotype was accompanied by a greater capacity of vascular infrastructure for sugar and water transport, but this was not associated with greater CO 2 uptake rates under growth conditions. The Swedish ecotype with its thick leaves is thus constructed for high intrinsic photosynthetic and vascular flux capacity even under growth chamber conditions that may not permit full utilization of this potential. Conversely, the Swedish ecotype was less tolerant of low growth light intensity than the Italian ecotype, with smaller rosette areas and lesser aboveground biomass accumulation in low light-grown plants. Foliar vein density and stomatal density were both enhanced by high growth light intensity with no significant difference between ecotypes, and the ratio of water to sugar conduits was also similar between the two ecotypes during light acclimation. These findings add to the understanding of the foliar vasculature's role in plant photosynthetic acclimation and adaptation.

Does plant trait diversity reduce the ability of herbivores to defend against predators? The plant variability-gut acclimation hypothesis.

Science.gov (United States)

Wetzel, William C; Thaler, Jennifer S

2016-04-01

Variability in plant chemistry has long been believed to suppress populations of insect herbivores by constraining herbivore resource selection behavior in ways that make herbivores more vulnerable to predation. The focus on behavior, however, overlooks the pervasive physiological effects of plant variability on herbivores. Here we propose the plant variability-gut acclimation hypothesis, which posits that plant chemical variability constrains herbivore anti-predator defenses by frequently requiring herbivores to acclimate their guts to changing plant defenses and nutrients. Gut acclimation, including changes to morphology and detoxification enzymes, requires time and nutrients, and we argue these costs will constrain how and when herbivores can mount anti-predator defenses. A consequence of this hypothesis is stronger top-down control of herbivores in heterogeneous plant populations. Copyright © 2016 Elsevier Inc. All rights reserved.

The temporal and species dynamics of photosynthetic acclimation in flag leaves of rice (Oryza sativa) and wheat (Triticum aestivum) under elevated carbon dioxide

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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)

Developmental acclimation to low or high humidity conditions affect starvation and heat resistance of Drosophila melanogaster.

Science.gov (United States)

Parkash, Ravi; Ranga, Poonam; Aggarwal, Dau Dayal

2014-09-01

Several Drosophila species originating from tropical humid localities are more resistant to starvation and heat stress than populations from high latitudes but mechanistic bases of such physiological changes are largely unknown. In order to test whether humidity levels affect starvation and heat resistance, we investigated developmental acclimation effects of low to high humidity conditions on the storage and utilization of energy resources, body mass, starvation survival, heat knockdown and heat survival of D. melanogaster. Isofemale lines reared under higher humidity (85% RH) stored significantly higher level of lipids and showed greater starvation survival hours but smaller in body size. In contrast, lines reared at low humidity evidenced reduced levels of body lipids and starvation resistance. Starvation resistance and lipid storage level were higher in females than males. However, the rate of utilization of lipids under starvation stress was lower for lines reared under higher humidity. Adult flies of lines reared at 65% RH and acclimated under high or low humidity condition for 200 hours also showed changes in resistance to starvation and heat but such effects were significantly lower as compared with developmental acclimation. Isofemale lines reared under higher humidity showed greater heat knockdown time and heat-shock survival. These laboratory observations on developmental and adult acclimation effects of low versus high humidity conditions have helped in explaining seasonal changes in resistance to starvation and heat of the wild-caught flies of D. melanogaster. Thus, we may suggest that wet versus drier conditions significantly affect starvation and heat resistance of D. melanogaster. Copyright © 2014 Elsevier Inc. All rights reserved.

Cold neutron radiography using low power accelerator

International Nuclear Information System (INIS)

Kiyanagi, Yoshiaki; Iwasa, Hirokatu

1993-01-01

A cold neutron source which can be adopted at a low power accelerator was studied. Time-of-flight radiography using the cold neutron source was performed. It is suggested that time-of-flight cold neutron radiography has possibility to distinguish the materials more clearly than the traditional film method since large contrast differences can be obtained by using digital data of the neutron intensity at different energies from thermal to cold region. Material will be identified at the same time by this method. (author)

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.

Effect of moderate hypoxia at three acclimation temperatures on stress responses in Atlantic cod with different haemoglobin types

DEFF Research Database (Denmark)

Methling, Caroline; Aluru, Neelakanteswar; Vijayan, Mathilakath M

2010-01-01

in a difference in stress response to hypoxia exposure. Two hsp70-isoforms (labelled a and b) were detected and they differed in expression in the gills but not in the liver of Atlantic cod. Acclimation temperature significantly affected the expression of hsp70 in the liver, and in an isoform-specific manner...... in the gills. Hypoxia exposure increased the expression of hsp70 in the liver, but not the gills, of cod and this response was not influenced by the acclimation temperature. The expression of hsp70 in both tissues did not differ between fish with different haemoglobin types. Acclimation temperature...... hypoxic exposure influence the organismal and cellular stress responses in Atlantic cod. We hypothesise that HbI-2 fish are more tolerant to short-term hypoxic episodes than HbI-1 fish, and this adaptation may be independent of tissue hsp70 expression....

Effects of acute cold exposure on oxidative balance and total antioxidant capacity in juvenile Chinese soft-shelled turtle, Pelodiscus sinensis.

Science.gov (United States)

Zhang, Wenyi; Niu, Cuijuan; Jia, Hui; Chen, Xutong

2017-09-01

Acute cold exposure may disturb the physiological homeostasis of the body in ectotherms. To date, there has been no information on the effects of cold exposure on homeostasis of reactive oxygen species (ROS) or antioxidant defense response in the Chinese soft-shelled turtle, Pelodiscus sinensis. In this study, P. sinensis juveniles were acclimated at 28 °C, transferred to 8 °C as cold exposure for 12 h, then moved back to 28 °C rewarming for 24 h. We measured the ROS level and total antioxidant capacity (TAC) in the brain, liver, kidney and spleen at 2 and 12 h cold exposure, and at the end of the rewarming period. Malonaldehyde (MDA) and carbonyl protein were used as markers of oxidative damage. Turtles being maintained simultaneously at 28 °C were used as the control group. Cold exposure did not disturb the ROS balance in all 4 tissues, while rewarming raised the ROS level in the brain and kidney of P. sinensis. Cold exposure and rewarming decreased the TAC in the brain, liver and spleen but did not change the TAC in the kidney. MDA and carbonyl protein levels did not increase during the treatment, indicating no oxidative damage in all 4 tissues of P. sinensis. Our results indicated that extreme cold exposure did not impact the inner oxidative balance of P. sinensis, but more ROS was produced during rewarming. P. sinensis showed good tolerance to the harsh temperature change through effective protection of its antioxidant defense system to oxidative damage. This study provides basic data on the stress biology of P. sinensis. © 2016 International Society of Zoological Sciences, Institute of Zoology/Chinese Academy of Sciences and John Wiley & Sons Australia, Ltd.

Grapevine acclimation to water deficit: the adjustment of stomatal and hydraulic conductance differs from petiole embolism vulnerability.

Science.gov (United States)

Hochberg, Uri; Bonel, Andrea Giulia; David-Schwartz, Rakefet; Degu, Asfaw; Fait, Aaron; Cochard, Hervé; Peterlunger, Enrico; Herrera, Jose Carlos

2017-06-01

Drought-acclimated vines maintained higher gas exchange compared to irrigated controls under water deficit; this effect is associated with modified leaf turgor but not with improved petiole vulnerability to cavitation. A key feature for the prosperity of plants under changing environments is the plasticity of their hydraulic system. In the present research we studied the hydraulic regulation in grapevines (Vitis vinifera L.) that were first acclimated for 39 days to well-watered (WW), sustained water deficit (SD), or transient-cycles of dehydration-rehydration-water deficit (TD) conditions, and then subjected to varying degrees of drought. Vine development under SD led to the smallest leaves and petioles, but the TD vines had the smallest mean xylem vessel and calculated specific conductivity (k ts ). Unexpectedly, both the water deficit acclimation treatments resulted in vines more vulnerable to cavitation in comparison to WW, possibly as a result of developmental differences or cavitation fatigue. When exposed to drought, the SD vines maintained the highest stomatal (g s ) and leaf conductance (k leaf ) under low stem water potential (Ψ s ), despite their high xylem vulnerability and in agreement with their lower turgor loss point (Ψ TLP ). These findings suggest that the down-regulation of k leaf and g s is not associated with embolism, and the ability of drought-acclimated vines to maintain hydraulic conductance and gas exchange under stressed conditions is more likely associated with the leaf turgor and membrane permeability.

Public Perception of Extreme Cold Weather-Related Health Risk in a Cold Area of Northeast China.

Science.gov (United States)

Ban, Jie; Lan, Li; Yang, Chao; Wang, Jian; Chen, Chen; Huang, Ganlin; Li, Tiantian

2017-08-01

A need exists for public health strategies regarding extreme weather disasters, which in recent years have become more frequent. This study aimed to understand the public's perception of extreme cold and its related health risks, which may provide detailed information for public health preparedness during an extreme cold weather event. To evaluate public perceptions of cold-related health risk and to identify vulnerable groups, we collected responses from 891 participants in a face-to-face survey in Harbin, China. Public perception was measured by calculating the score for each perception question. Locals perceived that extreme cold weather and related health risks were serious, but thought they could not avoid these risks. The significant difference in perceived acceptance level between age groups suggested that the elderly are a "high health risk, low risk perception" group, meaning that they are relatively more vulnerable owing to their high susceptibility and low awareness of the health risks associated with extreme cold weather. The elderly should be a priority in risk communication and health protective interventions. This study demonstrated that introducing risk perception into the public health field can identify vulnerable groups with greater needs, which may improve the decision-making of public health intervention strategies. (Disaster Med Public Health Preparedness. 2017;11:417-421).

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

International Nuclear Information System (INIS)

Dang Fei; Zhong Huan; Wang Wenxiong

2009-01-01

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 -1 day -1 . The efflux rate constant was 0.091 day -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 μg Cu L -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.

Physiological acclimation dampens initial effects of elevated temperature and atmospheric CO2 concentration in mature boreal Norway spruce.

Science.gov (United States)

Lamba, Shubhangi; Hall, Marianne; Räntfors, Mats; Chaudhary, Nitin; Linder, Sune; Way, Danielle; Uddling, Johan; Wallin, Göran

2018-02-01

Physiological processes of terrestrial plants regulate the land-atmosphere exchange of carbon, water, and energy, yet few studies have explored the acclimation responses of mature boreal conifer trees to climate change. Here we explored the acclimation responses of photosynthesis, respiration, and stomatal conductance to elevated temperature and/or CO 2 concentration ([CO 2 ]) in a 3-year field experiment with mature boreal Norway spruce. We found that elevated [CO 2 ] decreased photosynthetic carboxylation capacity (-23% at 25 °C) and increased shoot respiration (+64% at 15 °C), while warming had no significant effects. Shoot respiration, but not photosynthetic capacity, exhibited seasonal acclimation. Stomatal conductance at light saturation and a vapour pressure deficit of 1 kPa was unaffected by elevated [CO 2 ] but significantly decreased (-27%) by warming, and the ratio of intercellular to ambient [CO 2 ] was enhanced (+17%) by elevated [CO 2 ] and decreased (-12%) by warming. Many of these responses differ from those typically observed in temperate tree species. Our results show that long-term physiological acclimation dampens the initial stimulation of plant net carbon assimilation to elevated [CO 2 ], and of plant water use to warming. Models that do not account for these responses may thus overestimate the impacts of climate change on future boreal vegetation-atmosphere interactions. © 2017 John Wiley & Sons Ltd.

Amphibious fish jump better on land after acclimation to a terrestrial environment.

Science.gov (United States)

Brunt, Emily M; Turko, Andy J; Scott, Graham R; Wright, Patricia A

2016-10-15

Air and water differ dramatically in density and viscosity, posing different biomechanical challenges for animal locomotion. We asked how terrestrial acclimation influences locomotion in amphibious fish, specifically testing the hypothesis that terrestrial tail flip performance is improved by plastic changes in the skeletal muscle. Mangrove rivulus Kryptolebias marmoratus, which remain largely inactive out of water, were exposed to water or air for 14 days and a subgroup of air-exposed fish was also recovered in water. Tail flip jumping performance on land improved dramatically in air-acclimated fish, they had lower lactate levels compared with control fish, and these effects were mostly reversible. Muscle plasticity significantly increased oxidative muscle cross-sectional area and fibre size, as well as the number of capillaries per fibre. Our results show that reversible changes to the oxidative skeletal muscle of K. marmoratus out of water enhance terrestrial locomotory performance, even in the absence of exercise training. © 2016. Published by The Company of Biologists Ltd.

Detection of cold pain, cold allodynia and cold hyperalgesia in freely behaving rats

Directory of Open Access Journals (Sweden)

Woolf Clifford J

2005-12-01

Full Text Available Abstract Background Pain is elicited by cold, and a major feature of many neuropathic pain states is that normally innocuous cool stimuli begin to produce pain (cold allodynia. To expand our understanding of cold induced pain states we have studied cold pain behaviors over a range of temperatures in several animal models of chronic pain. Results We demonstrate that a Peltier-cooled cold plate with ± 1°C sensitivity enables quantitative measurement of a detection withdrawal response to cold stimuli in unrestrained rats. In naïve rats the threshold for eliciting cold pain behavior is 5°C. The withdrawal threshold for cold allodynia is 15°C in both the spared nerve injury and spinal nerve ligation models of neuropathic pain. Cold hyperalgesia is present in the spared nerve injury model animals, manifesting as a reduced latency of withdrawal response threshold at temperatures that elicit cold pain in naïve rats. We also show that following the peripheral inflammation produced by intraplantar injection of complete Freund's adjuvant, a hypersensitivity to cold occurs. Conclusion The peltier-cooled provides an effective means of assaying cold sensitivity in unrestrained rats. Behavioral testing of cold allodynia, hyperalgesia and pain will greatly facilitate the study of the neurobiological mechanisms involved in cold/cool sensations and enable measurement of the efficacy of pharmacological treatments to reduce these symptoms.

Interactive effects of ambient acidity and salinity on thyroid function during acidic and post-acidic acclimation of air-breathing fish (Anabas testudineus Bloch).

Science.gov (United States)

Peter, M C Subhash; Rejitha, V

2011-11-01

The interactive effects of ambient acidity and salinity on thyroid function are less understood in fish particularly in air-breathing fish. We, therefore, examined the thyroid function particularly the osmotic and metabolic competences of freshwater (FW) and salinity-adapted (SA; 20 ppt) air-breathing fish (Anabas testudineus) during acidic and post-acidic acclimation, i.e., during the exposure of fish to either acidified water (pH 4.2 and 5.2) for 48 h or clean water for 96 h after pre-exposure. A substantial rise in plasma T(4) occurred after acidic exposure of both FW and SA fish. Similarly, increased plasma T(3) and T(4) were found in FW fish kept for post-acidic acclimation and these suggest an involvement of THs in short-term acidic and post-acidic acclimation. Water acidification produced significant hyperglycaemia and hyperuremia in FW fish but not in SA fish. The SA fish when kept for post-acclimation, however, produced a significant hypouremia. In both FW and SA fish, gill Na(+), K(+)-ATPase activity decreased but kidney Na(+), K(+)-ATPase activity increased upon acidic acclimation. During post-acidic acclimation, gill Na(+), K(+)-ATPase activity of the FW fish showed a rise while decreasing its activity in the SA fish. Similarly, post-acidic acclimation reduced the Na(+), K(+)-ATPase activity of intestine but elevated its activity in the liver of SA fish. A higher tolerance of the SA fish to water acidification was evident in these fish as they showed tight plasma and tissue mineral status due to the ability of this fish to counteract the ion loss. In contrast, FW fish showed more sensitivity to water acidification as they loose more ions in that medium. The positive correlations of plasma THs with many tested metabolic and hydromineral indices of both FW and SA fish and also with water pH further confirm the involvement of THs in acidic and post-acidic acclimation in these fish. We conclude that thyroid function of this fish is more sensitive to

A transcriptomic analysis of bermudagrass (Cynodon dactylon) provides novel insights into the basis of low temperature tolerance.

Science.gov (United States)

Chen, Liang; Fan, Jibiao; Hu, Longxing; Hu, Zhengrong; Xie, Yan; Zhang, Yingzi; Lou, Yanhong; Nevo, Eviatar; Fu, Jinmin

2015-09-11

Cold stress is regarded as a key factor limiting widespread use for bermudagrass (Cynodon dactylon). Therefore, to improve cold tolerance for bermudagrass, it is urgent to understand molecular mechanisms of bermudagrass response to cold stress. However, our knowledge about the molecular responses of this species to cold stress is largely unknown. The objective of this study was to characterize the transcriptomic response to low temperature in bermudagrass by using RNA-Seq platform. Ten cDNA libraries were generated from RNA samples of leaves from five different treatments in the cold-resistant (R) and the cold-sensitive (S) genotypes, including 4 °C cold acclimation (CA) for 24 h and 48 h, freezing (-5 °C) treatments for 4 h with or without prior CA, and controls. When subjected to cold acclimation, global gene expressions were initiated more quickly in the R genotype than those in the S genotype. The R genotype activated gene expression more effectively in response to freezing temperature after 48 h CA than the S genotype. The differentially expressed genes were identified as low temperature sensing and signaling-related genes, functional proteins and transcription factors, many of which were specifically or predominantly expressed in the R genotype under cold treatments, implying that these genes play important roles in the enhanced cold hardiness of bermudagrass. KEGG pathway enrichment analysis for DEGs revealed that photosynthesis, nitrogen metabolism and carbon fixation pathways play key roles in bermudagrass response to cold stress. The results of this study may contribute to our understanding the molecular mechanism underlying the responses of bermudagrass to cold stress, and also provide important clues for further study and in-depth characterization of cold-resistance breeding candidate genes in bermudagrass.

Renal Cu and Na excretion and hepatic Cu metabolism in both Cu acclimated and non acclimated rainbow trout (Oncorhynchus mykiss)

DEFF Research Database (Denmark)

Grosell, M.; Hogstrand, C.; Wood, C.M.

1998-01-01

protein depending on whether the Cu is derived from recent branchial uptake or is already present in the plasma prior to Cu-64 exposure. The plasma Cu pool derived from recent branchial uptake and the Cu pool present in the plasma prior to Cu-64 exposure is accessible to renal excretion to different...... Na+ efflux decreased by 40%, which was largely due to increased tubular Na+ reabsorption. Renal compensation for the impaired branchial Na+ uptake, seen during Cu exposure, thus seems to be involved in Cu acclimation in rainbow trout. (C) 1998 Elsevier Science B.V....

Pre-anthesis high temperature acclimation alleviates the negative effects of postanthesis heat stress on stem stored carbohydrates remobilization and grain starch accumulation in wheat

DEFF Research Database (Denmark)

Wang, Xiao; Cai, Jian; Liu, Fulai

2012-01-01

The potential role of pre-anthesis high temperature acclimation in alleviating the negative effects of post-anthesis heat stress on stem stored carbohydrate remobilization and grain starch accumulation in wheat was investigated. The treatments included no heat-stress (CC), heat stress at pre...... had much higher starch content, and caused less modified B-type starch granule size indicators than the CH plants. Our results indicated that, compared with the non-acclimated plants, the pre-anthesis high temperature acclimation effectively enhanced carbohydrate remobilization from stems to grains...

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

Alterations in mitochondrial electron transport system activity in response to warm acclimation, hypoxia-reoxygenation and copper in rainbow trout, Oncorhynchus mykiss

International Nuclear Information System (INIS)

Sappal, Ravinder; MacDougald, Michelle; Fast, Mark; Stevens, Don; Kibenge, Fred; Siah, Ahmed; Kamunde, Collins

2015-01-01

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

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

Plasticity and stress tolerance override local adaptation in the responses of Mediterranean holm oak seedlings to drought and cold.

Science.gov (United States)

Gimeno, Teresa E; Pías, Beatriz; Lemos-Filho, José P; Valladares, Fernando

2009-01-01

Plant populations of widely distributed species experience a broad range of environmental conditions that can be faced by phenotypic plasticity or ecotypic differentiation and local adaptation. The strategy chosen will determine a population's ability to respond to climate change. To explore this, we grew Quercus ilex (L.) seedlings from acorns collected at six selected populations from climatically contrasting localities and evaluated their response to drought and late season cold events. Maximum photosynthetic rate (A(max)), instantaneous water use efficiency (iWUE), and thermal tolerance to freeze and heat (estimated from chlorophyll fluorescence versus temperature curves) were measured in 5-month-old seedlings in control (no stress), drought (water-stressed), and cold (low suboptimal temperature) conditions. The observed responses were similar for the six populations: drought decreased A(max) and increased iWUE, and cold reduced A(max) and iWUE. All the seedlings maintained photosynthetic activity under adverse conditions (drought and cold), and rapidly increased their iWUE by closing stomata when exposed to drought. Heat and freeze tolerances were similarly high for seedlings from all the populations, and they were significantly increased by drought and cold, respectively; and were positively related to each other. Differences in seedling performance across populations were primarily induced by maternal effects mediated by seed size and to a lesser extent by idiosyncratic physiologic responses to drought and low temperatures. Tolerance to multiple stresses together with the capacity to physiologically acclimate to heat waves and cold snaps may allow Q. ilex to cope with the increasingly stressful conditions imposed by climate change. Lack of evidence of physiologic seedling adaptation to local climate may reflect opposing selection pressures to complex, multidimensional environmental conditions operating within the distribution range of this species.

Cutaneous vasoregulation during short- and long-term aerial acclimation in the amphibious mangrove rivulus, Kryptolebias marmoratus.

Science.gov (United States)

Cooper, C A; Litwiller, S L; Murrant, C L; Wright, P A

2012-03-01

The mangrove rivulus (Kryptolebias marmoratus) is an amphibious fish and evidence suggests that the cutaneous surface is the primary site of gas exchange during emersion. The aim of this study was to determine whether cutaneous blood vessels were regulated in the caudal fin during the initial transition from water to aerial exposure, and after 10 days of aerial acclimation. Acute changes (first 3 min following emersion) in the cutaneous vessels diameter were measured in real-time on live fish using light microscopy. The data show that under control conditions, only arterioles in the caudal fin were vasoactive. During the first 20s of aerial acclimation the arterioles significantly constricted (-2.1 ± 0.4 μm), which was followed immediately by a relaxation (from 40 to 180 s). This vasoconstriction was eliminated with the addition of phentolamine (50 μmoll(-1)), which indicates that the vasoconstriction was mediated by α-adrenoreceptors. Longer-term changes in the cutaneous surface vasculature were determined using fluorescent immunohistochemistry and antibodies for the endothelial marker, CD31. Fish aerially acclimated for 10 days exhibited significantly higher levels of endothelial fluorescence in the caudal fin when compared to control fish in water, indicating endothelial cell production (i.e. angiogenesis). These data combined show that for every emersion episode, there is an initial α-adrenergic mediated vasoconstriction, which is most likely, a stress response. This is then followed by a long-term acclimation involving an upregulation in endothelial cell production, which would subsequently enhance blood perfusion to the cutaneous surface and potentially increase the capacity for gas exchange with the external environment. Copyright © 2011 Elsevier Inc. All rights reserved.

The cold-induced defensin TAD1 confers resistance against snow mold and Fusarium head blight in transgenic wheat.

Science.gov (United States)

Sasaki, Kentaro; Kuwabara, Chikako; Umeki, Natsuki; Fujioka, Mari; Saburi, Wataru; Matsui, Hirokazu; Abe, Fumitaka; Imai, Ryozo

2016-06-20

TAD1 (Triticum aestivum defensin 1) is induced during cold acclimation in winter wheat and encodes a plant defensin with antimicrobial activity. In this study, we demonstrated that recombinant TAD1 protein inhibits hyphal growth of the snow mold fungus, Typhula ishikariensis in vitro. Transgenic wheat plants overexpressing TAD1 were created and tested for resistance against T. ishikariensis. Leaf inoculation assays revealed that overexpression of TAD1 confers resistance against the snow mold. In addition, the TAD1-overexpressors showed resistance against Fusarium graminearum, which causes Fusarium head blight, a devastating disease in wheat and barley. These results indicate that TAD1 is a candidate gene to improve resistance against multiple fungal diseases in cereal crops. Copyright © 2016 Elsevier B.V. All rights reserved.

Salinity- and population-dependent genome regulatory response during osmotic acclimation in the killifish (Fundulus heteroclitus) gill.

Science.gov (United States)

Whitehead, Andrew; Roach, Jennifer L; Zhang, Shujun; Galvez, Fernando

2012-04-15

The killifish Fundulus heteroclitus is abundant in osmotically dynamic estuaries and it can quickly adjust to extremes in environmental salinity. We performed a comparative osmotic challenge experiment to track the transcriptomic and physiological responses to two salinities throughout a time course of acclimation, and to explore the genome regulatory mechanisms that enable extreme osmotic acclimation. One southern and one northern coastal population, known to differ in their tolerance to hypo-osmotic exposure, were used as our comparative model. Both populations could maintain osmotic homeostasis when transferred from 32 to 0.4 p.p.t., but diverged in their compensatory abilities when challenged down to 0.1 p.p.t., in parallel with divergent transformation of gill morphology. Genes involved in cell volume regulation, nucleosome maintenance, ion transport, energetics, mitochondrion function, transcriptional regulation and apoptosis showed population- and salinity-dependent patterns of expression during acclimation. Network analysis confirmed the role of cytokine and kinase signaling pathways in coordinating the genome regulatory response to osmotic challenge, and also posited the importance of signaling coordinated through the transcription factor HNF-4α. These genome responses support hypotheses of which regulatory mechanisms are particularly relevant for enabling extreme physiological flexibility.

Lichens show that fungi can acclimate their respiration to seasonal changes in temperature.

Science.gov (United States)

Lange, Otto L; Green, T G Allan

2005-01-01

Five species of lichens, the majority members of a soil-crust community ( Cladonia convoluta, Diploschistes muscorum, Fulgensia fulgens, Lecanora muralis, Squamarina lentigera) showed seasonal changes of temperature sensitivity of their dark respiration (DR) to such an extent that several substantially met the definition of full acclimation, i.e. near identical DR under different nocturnal temperature conditions during the course of the year. C. convoluta, for example, had maximal DR at 5 degrees C of -0.42, -1.11 and -0.09 nmol CO(2) g(-1) s(-1) in autumn, winter, and summer, respectively, a tenfold range. However, at the mean night temperatures for the same three seasons, 9.7 degrees C, 4.2 degrees C and 13.6 degrees C, maximal DR were almost identical at -1.11, -0.93, and -1.45 nmol CO(2) g(-1) s(-1). The information was extracted from measurements using automatic cuvettes that continuously recorded a sample lichen's gas exchange every 30 min under near-natural conditions. The longest period (for L. muralis) covered 15 months and 22,000 data sets whilst, for the other species studied, data blocks were available throughout the calendar year. The acclimation of DR means that maximal net carbon fixation rates remain substantially similar throughout the year and are not depressed by increased carbon loss by respiration in warmer seasons. This is especially important for lichens because of their normally high rate of DR compared to net photosynthesis. We suggest that lichens, especially soil-crust species, could be a suitable model for fungi generally, a group of organisms for which little is known about temperature acclimation because of the great difficulty in separating the organism from its growth medium. Fungi, whether saprophytic, symbiotic or parasitic, including soil lichens, are important components of soil ecosystems and contribute much of the respired CO(2) from these systems. Temperature acclimation by fungi would mean that expected increases in carbon

Thermal acclimation and thyroxine treatment modify the electric organ discharge frequency in an electric fish, Apteronotus leptorhynchus.

Science.gov (United States)

Dunlap, K D; Ragazzi, M A

2015-11-01

In ectotherms, the rate of many neural processes is determined externally, by the influence of the thermal environment on body temperature, and internally, by hormones secreted from the thyroid gland. Through thermal acclimation, animals can buffer the influence of the thermal environment by adjusting their physiology to stabilize certain processes in the face of environmental temperature change. The electric organ discharge (EOD) used by weak electric fish for electrocommunication and electrolocation is highly temperature sensitive. In some temperate species that naturally experience large seasonal fluctuations in environmental temperature, the thermal sensitivity (Q10) of the EOD shifts after long-term temperature change. We examined thermal acclimation of EOD frequency in a tropical electric fish, Apteronotus leptorhynchus that naturally experiences much less temperature change. We transferred fish between thermal environments (25.3 and 27.8 °C) and measured EOD frequency and its thermal sensitivity (Q10) over 11 d. After 6d, fish exhibited thermal acclimation to both warming and cooling, adjusting the thermal dependence of EOD frequency to partially compensate for the small change (2.5 °C) in water temperature. In addition, we evaluated the thyroid influence on EOD frequency by treating fish with thyroxine or the anti-thyroid compound propylthiouricil (PTU) to stimulate or inhibit thyroid activity, respectively. Thyroxine treatment significantly increased EOD frequency, but PTU had no effect. Neither thyroxine nor PTU treatment influenced the thermal sensitivity (Q10) of EOD frequency during acute temperature change. Thus, the EOD of Apteronotus shows significant thermal acclimation and responds to elevated thyroxine. Copyright © 2015 Elsevier Inc. All rights reserved.

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.

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.

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.

Carbonic anhydrase (acetazolamide-sensitive esterase) activity in the blood, gill and kidney of the thermally acclimated rainbow trout, Salmo gairdneri

Energy Technology Data Exchange (ETDEWEB)

Houston, A.H.; McCarty, L.S.

1978-04-01

Gill, kidney and blood levels of acetazolamide-sensitive esterase (carbonic anhydrase) activity were estimated at acclimation temperature and at a common temperature (25/sup 0/C) in rainbow trout acclimated to 2, 10, and 18/sup 0/C. Plasma levels of sodium, potassium and chloride were also examined for possible acclimatory variations. Plasma sodium and chloride levels, and the sodium:chloride ratio were unaffected by thermal acclimation; potassium concentrations were significantly elevated at 18/sup 0/C. Significant, but modest changes in renal and branchial carbonic anhydrase activity were observed under physiologically realistic incubation temperature conditions. Blood carbonic anhydrase activity was sharply elevated at higher acclimation temperatures. The data are discussed in relation to the hypothesis that carbonic anhydrase in this relatively stenothermal freshwater salmonid, through its intimate association with the coupled HCO/sub 3//sup -//Cl/sup -/ and H/sup +/ + NH/sub 4//sup +//Na/sup +/ exchange systems may provide for relatively thermostable basal rates of sodium and chloride uptake from the medium and recovery from urine. The renal, and more notably the branchial (Na/sup +//K/sup +/)-simulated ATPase systems, and erythrocytic carbonic anhydrase may then serve primarily as high-temperature amplifiers of sodium and chloride recruitment respectively.

Can acclimation of thermal tolerance, in adults and across generations, act as a buffer against climate change in tropical marine ectotherms?

Science.gov (United States)

Morley, S A; Nguyen, K D; Peck, L S; Lai, C-H; Tan, K S

2017-08-01

Thermal acclimation capacity was investigated in adults of three tropical marine invertebrates, the subtidal barnacle Striatobalanus amaryllis, the intertidal gastropod Volegalea cochlidium and the intertidal barnacle Amphibalanus amphitrite. To test the relative importance of transgenerational acclimation, the developmental acclimation capacity of A. amphitrite was investigated in F 1 and F 2 generations reared at a subset of the same incubation temperatures. The increase in CT max (measured through loss of key behavioural metrics) of F 0 adults across the incubation temperature range 25.4-33.4°C was low: 0.00°C (V. cochlidium), 0.05°C (S. amaryllis) and 0.06°C (A. amphitrite) per 1°C increase in incubation temperature (the acclimation response ratio; ARR). Although the effect of generation was not significant, across the incubation temperature range of 29.4-33.4°C, the increase in CT max in the F 1 (0.30°C) and F 2 (0.15°C) generations of A. amphitrite was greater than in the F 0 (0.10°C). These correspond to ARR's of 0.03°C (F 0 ), 0.08°C (F 1 ) and 0.04°C (F 2 ), respectively. The variability in CT max between individuals in each treatment was maintained across generations, despite the high mortality of progeny. Further research is required to investigate the potential for transgenerational acclimation to provide an extra buffer for tropical marine species facing climate warming. Copyright © 2016 Elsevier Ltd. All rights reserved.

Acclimation-induced changes in toxicity and induction of metallothionein-like proteins in the fathead minnow following sublethal exposure to cobalt, silver, and zinc

International Nuclear Information System (INIS)

Hobson, J.F.

1986-01-01

Increases in tolerance and resistance to metal toxicity by aquatic organisms have been linked to elevated levels of low-molecular-weight metal-binding proteins (e.g., metallothioneins). Acclimation-induced changes in toxic response and the concentration of metallothionein-like proteins (MTP) were studied in laboratory populations of the fathead minnow, Pimephales promelas, following sublethal exposure to Co, Ag, and Zn. Following 7 and 14 days of sublethal exposure, tolerance and resistance, as measured by acute toxicity values, were altered in a dose dependent fashion. Acute toxicity values returned to control levels after 21 days of continuous exposure. Tolerance and resistance of Co- and Zn-acclimated animals were depressed after a 7-day post-acclimation period in control water. Tolerance and resistance of Ag-acclimated animals were temporarily enhanced after 7 days post-acclimation and returned to control levels after 14 days. Accumulation of Co, Ag, and Zn measured as wholebody residues appeared to be regulated in 4 of 6 exposure regimes with residues reaching stable levels after 7 to 14 days of exposure. MTP was induced by exposure to 1.8 mg Zn/L and 0.01 mg Ag/L, however, no sustained (i.e., post 21 days) tolerance or resistance were observed at these dose levels indicating that these two biological responses may not be directly related

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

, acclimation of Lostine River spring Chinook salmon smolts occurred from March 1, 2004 through to April 14, 2004 and a total of 250,249 smolts were acclimated and released. These smolts were produced from the brood year (BY) 2002 egg source and included captive brood (133,781) and conventional (116,468) origin smolts that were all progeny of Lostine River spring Chinook salmon. Operation of the Lostine River adult monitoring and collection facility in 2004 began May 10, the first Chinook was captured on May 19, 2004 and the last Chinook was captured on September 16, 2004. The weir and trap were removed on October 1, 2004. A total of 1,091 adult Chinook, including jacks, were captured during the season. The composition of the run included 299 natural origin fish and 792 hatchery supplementation fish. There were no identified 'stray' hatchery fish from other programs trapped. Of the fish captured, 46 natural and 69 hatchery supplementation adults were retained for broodstock and transported to Lookingglass Hatchery for holding and spawning, 537 adult Chinook were passed or transported above the weir to spawn naturally, and 447 hatchery origin adult Chinook were transported and outplanted in the Wallowa River and Bear Creek to spawn in underseeded habitat. Of the 107 adults retained (eight additional hatchery females were collected and then later returned to the Lostine River to spawn naturally) for broodstock at Lookingglass Hatchery, 22 natural females and 30 supplementation females were represented in spawning. These females produced a total of 221,889 eggs at fertilization. Eye-up was 94.9% which yielded a total of 210,661 conventional program eyed eggs. The fecundity averaged 4,267 eggs per female. These eggs were incubated and at Lookingglass Hatchery until eyed stage and then transferred to Oxbow Hatchery where they will be reared to the fingerling stage. They will then be transported back to LGH and reared to the smolt stage and then transported to the Lostine

Simultaneous enhancement of phenolic compound degradations by Acinetobacter strain V2 via a step-wise continuous acclimation process.

Science.gov (United States)

Lin, Johnson; Sharma, Vikas; Milase, Ridwaan; Mbhense, Ntuthuko

2016-06-01

Phenol degradation enhancement of Acinetobacter strain V2 by a step-wise continuous acclimation process was investigated. At the end of 8 months, three stable adapted strains, designated as R, G, and Y, were developed with the sub-lethal concentration of phenol at 800, 1100, and 1400 mg/L, respectively, from 400 mg/L of V2 parent strain. All strains degraded phenol at their sub-lethal level within 24 h, their growth rate increased as the acclimation process continued and retained their degradation properties even after storing at -80 °C for more than 3 years. All adapted strains appeared coccoid with an ungranulated surface under electron microscope compared to typical rod-shaped parental strain V2 . The adapted Y strain also possessed superior degradation ability against aniline, benzoate, and toluene. This study demonstrated the use of long term acclimation process to develop efficient and better pollutant degrading bacterial strains with potentials in industrial and environmental bioremediation. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Inconsistent effects of developmental temperatureacclimation on low-temperature performance andmetabolism in Drosophila melanogaster

DEFF Research Database (Denmark)

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

2012-01-01

Question: Does acclimation to developmental temperature consistently affect metabolismand low-temperature performance when measured in different laboratory and field assays? Hypothesis: Developmental acclimation reflecting naturally fluctuating thermal conditionsconsistently increases different...... conditions in the field, while constant cool rearingconditions led to high cold resistance. The fluctuating- and low-temperature rearing conditionsresulted in a similar metabolic profile, while the 24C rearing profile was distinct and showeda lack of plasticity. The effects of developmental acclimation...

Effects of Heat Acclimation on Photosynthesis, Antioxidant Enzyme Activities, and Gene Expression in Orchardgrass under Heat Stress

Directory of Open Access Journals (Sweden)

Xin Xin Zhao

2014-09-01

Full Text Available 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.

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. © 2014 The Society for Applied Microbiology.

Multiple cold resistance loci confer the high cold tolerance adaptation of Dongxiang wild rice (Oryza rufipogon) to its high-latitude habitat.

Science.gov (United States)

Mao, Donghai; Yu, Li; Chen, Dazhou; Li, Lanying; Zhu, Yuxing; Xiao, Yeqing; Zhang, Dechun; Chen, Caiyan

2015-07-01

Dongxiang wild rice is phylogenetically close to temperate japonica and contains multiple cold resistance loci conferring its adaptation to high-latitude habitat. Understanding the nature of adaptation in wild populations will benefit crop breeding in the development of climate-resilient crop varieties. Dongxiang wild rice (DXWR), the northernmost common wild rice known, possesses a high degree of cold tolerance and can survive overwintering in its native habitat. However, to date, it is still unclear how DXWR evolved to cope with low-temperature environment, resulting in limited application of DXWR in rice breeding programs. In this study, we carried out both QTL mapping and phylogenetic analysis to discern the genetic mechanism underlying the strong cold resistance. Through a combination of interval mapping and single locus analysis in two genetic populations, at least 13 QTLs for seedling cold tolerance were identified in DXWR. A phylogenetic study using both genome-wide InDel markers and markers associated with cold tolerance loci reveals that DXWR belongs to the Or-III group, which is most closely related to cold-tolerant Japonica rice rather than to the Indica cultivars that are predominant in the habitat where DXWR grows. Our study paves the way toward an understanding of the nature of adaptation to a northern habitat in O. rufipogon. The QTLs identified in DXWR in this study will be useful for molecular breeding of cold-tolerant rice.

Predicting worsening asthma control following the common cold

NARCIS (Netherlands)

Walter, M. J.; Castro, M.; Kunselman, S. J.; Chinchilli, V. M.; Reno, M.; Ramkumar, T. P.; Avila, P. C.; Boushey, H. A.; Ameredes, B. T.; Bleecker, E. R.; Calhoun, W. J.; Cherniack, R. M.; Craig, T. J.; Denlinger, L. C.; Israel, E.; Fahy, J. V.; Jarjour, N. N.; Kraft, M.; Lazarus, S. C.; Lemanske, R. F.; Martin, R. J.; Peters, S. P.; Ramsdell, J. W.; Sorkness, C. A.; Sutherland, E. R.; Szefler, S. J.; Wasserman, S. I.; Wechsler, M. E.

2008-01-01

The asthmatic response to the common cold is highly variable, and early characteristics that predict worsening of asthma control following a cold have not been identified. In this prospective multicentric cohort study of 413 adult subjects with asthma, the mini-Asthma Control Questionnaire

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

KAUST Repository

Xiao, Xi; de Bettignies, Thibaut; Olsen, Ylva S.; Agusti, Susana; Duarte, Carlos M.; Wernberg, Thomas

2015-01-01

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.

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.

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.

Foraging response and acclimation of ambush feeding and feeding-current feeding copepods to toxic dinoflagellates

DEFF Research Database (Denmark)

Xu, Jiayi; Nielsen, Lasse Tor; Kiørboe, Thomas

2018-01-01

reticulatum. We hypothesize (1) that ambush feeders are less affected by toxic algae than feeding-current feeders, (2) that copepods acclimate to the toxic algae, and (3) that phytoplankton cells previously exposed to copepod cues elicit stronger responses. Both copepod species consumed the toxic algae...... to examine the response and temporal acclimation (5 d) of two copepods with different foraging behaviors to toxic dinoflagellates. Feeding-current feeding Temora longicornis and ambush feeding Acartia tonsa were offered three strains of toxic Alexandrium tamarense and a nontoxic control Protoceratium...... at a reduced rate and there was no difference in their net-response, but the mechanisms differed. T. longicornis responded in strain-specific ways by reducing its feeding activity, by rejecting captured algae, or by regurgitating consumed cells. A. tonsa reduced its consumption rate, jump frequency, and jump...

How cold is cold dark matter?

International Nuclear Information System (INIS)

Armendariz-Picon, Cristian; Neelakanta, Jayanth T.

2014-01-01

If cold dark matter consists of particles, these must be non-interacting and non-relativistic by definition. In most cold dark matter models however, dark matter particles inherit a non-vanishing velocity dispersion from interactions in the early universe, a velocity that redshifts with cosmic expansion but certainly remains non-zero. In this article, we place model-independent constraints on the dark matter temperature to mass ratio, whose square root determines the dark matter velocity dispersion. We only assume that dark matter particles decoupled kinetically while non-relativistic, when galactic scales had not entered the horizon yet, and that their momentum distribution has been Maxwellian since that time. Under these assumptions, using cosmic microwave background and matter power spectrum observations, we place upper limits on the temperature to mass ratio of cold dark matter today (away from collapsed structures). These limits imply that the present cold dark matter velocity dispersion has to be smaller than 54 m/s. Cold dark matter has to be quite cold, indeed

Conserved effects of salinity acclimation on thermal tolerance and hsp70 expression in divergent populations of threespine stickleback (Gasterosteus aculeatus).

Science.gov (United States)

Metzger, David C H; Healy, Timothy M; Schulte, Patricia M

2016-10-01

In natural environments, organisms must cope with complex combinations of abiotic stressors. Here, we use threespine stickleback (Gasterosteus aculeatus) to examine how changes in salinity affect tolerance of high temperatures. Threespine stickleback inhabit a range of environments that vary in both salinity and thermal stability making this species an excellent system for investigating interacting stressors. We examined the effects of environmental salinity on maximum thermal tolerance (CTMax) and 70 kDa heat shock protein (hsp70) gene expression using divergent stickleback ecotypes from marine and freshwater habitats. In both ecotypes, the CTMax of fish acclimated to 20 ppt was significantly higher compared to fish acclimated to 2 ppt. The effect of salinity acclimation on the expression of hsp70-1 and hsp70-2 was similar in both the marine and freshwater stickleback ecotype. There were differences in the expression profiles of hsp70-1 and hsp70-2 during heat shock, with hsp70-2 being induced earlier and to a higher level compared to hsp70-1. These data suggest that the two hsp70 isoforms may have functionally different roles in the heat shock response. Lastly, acute salinity challenge coupled with heat shock revealed that the osmoregulatory demands experienced during the heat shock response have a larger effect on the hsp70 expression profile than does the acclimation salinity.

Cold Antimatter Plasmas, and Aspirations for Cold Antihydrogen

Science.gov (United States)

2002-06-24

UNCLASSIFIED Defense Technical Information Center Compilation Part Notice ADP012494 TITLE: Cold Antimatter Plasmas, and Aspirations for Cold...part numbers comprise the compilation report: ADP012489 thru ADP012577 UNCLASSIFIED Cold Antimatter Plasmas, and Aspirations for Cold Antihydrogen G...and positrons. The antiprotons come initially from the new Antiproton Decel- erator facility at CERN. Good control of such cold antimatter plasmas is

Workshop on cold-blanket research

International Nuclear Information System (INIS)

1977-05-01

The objective of the workshop was to identify and discuss cold-plasma blanket systems. In order to minimize the bombardment of the walls by hot neutrals the plasma should be impermeable. This requires a density edge-thickness product of nΔ > 10 15 cm -2 . An impermeable cold plasma-gas blanket surrounding a hot plasma core reduces the plasma wall/limiter interaction. Accumulation of impurities in this blanket can be expected. Fuelling from a blanket may be possible as shown by experimental results, though not fully explained by classical transport of neutrals. Refuelling of a reacting plasma had to be ensured by inward diffusion. Experimental studies of a cold impermeable plasma have been done on the tokamak-like Ringboog device. Simulation calculations for the next generation of large tokamaks using a particular transport model, indicate that the plasma edge profile can be controlled to reduce the production of sputtered impurities to an acceptable level. Impurity control requires a small fraction of the radial space to accomodate the cold-plasma layer. The problem of exhaust is, however, more complicated. If the cold-blanket scheme works as predicted in the model calculations, then α-particles generated by fusion will be transported to the cold outside layer. The Communities' experimental programme of research has been discussed in terms of the tokamaks which are available and planned. Two options present themselves for the continuation of cold-blanket research

Cold regions isotope applications

International Nuclear Information System (INIS)

Perrigo, L.D.; Divine, T.E.

1976-04-01

Pacific Northwest Laboratories (PNL) started the Cold Regions Isotope Applications Program in FY-1975 to identify special conditions in the Arctic and similar geographic areas (Cold Regions) where radioisotope power, heater, or sterilization systems would be desirable and economically viable. Significant progress was made in the first year of this program and all objectives for this initial 12-month period were achieved. The major conclusions and recommendations resulting for this effort are described below. The areas of interest covered include: radiosterilization of sewage; heating of septic tanks; and radioisotope thermoelectric generators as power sources for meteorological instruments and navigational aids

Adenosine monophosphate-activated protein kinase from the mud ...

Indian Academy of Sciences (India)

2016-12-01

Dec 1, 2016 ... to the understanding of the molecular mechanism of acclimation to cold hardiness in S. ... have shown that the stress associated with cold temperature ..... vation by cyclic-AMP-dependent protein kinase, studied using.

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

KAUST Repository

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

2016-01-01

) 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

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

pump activity, changes in abundance and possibly localization of this protein did not appear to contribute to soft water acclimation. Active Cl(-) uptake was strongly dependent on branchial carbonic anhydrase (CA) activity regardless of water type, while the response of Na(+) transport to a CA...

COLD-SAT feasibility study safety analysis

Science.gov (United States)

Mchenry, Steven T.; Yost, James M.

1991-01-01

The Cryogenic On-orbit Liquid Depot-Storage, Acquisition, and Transfer (COLD-SAT) satellite presents some unique safety issues. The feasibility study conducted at NASA-Lewis desired a systems safety program that would be involved from the initial design in order to eliminate and/or control the inherent hazards. Because of this, a hazards analysis method was needed that: (1) identified issues that needed to be addressed for a feasibility assessment; and (2) identified all potential hazards that would need to be controlled and/or eliminated during the detailed design phases. The developed analysis method is presented as well as the results generated for the COLD-SAT system.

Seasonal alteration of sugar metabolism in strawberry ( Fragaria ...

African Journals Online (AJOL)

Plants of strawberry cvs Aromas and Diamante were removed from the field in cold acclimated (CA, January) and non-acclimated (NA, July) stages. Crown parts of the plant were used for analysis. Apoplastic total soluble sugar (TSS), reducing sugars and sucrose contents did not change in both cultivars in both sampling ...

Regulation of H+ Extrusion and Cytoplasmic pH in Maize Root Tips Acclimated to a Low-Oxygen Environment.

Science.gov (United States)

Xia, J. H.; Roberts, JKM.

1996-05-01

We tested the hypothesis that H+ extrusion contributes to cytoplasmic pH regulation and tolerance of anoxia in maize (Zea mays) root tips. We studied root tips of whole seedlings that were acclimated to a low-oxygen environment by pretreatment in 3% (v/v) O2. Acclimated root tips characteristically regulate cytoplasmic pH near neutrality and survive prolonged anoxia, whereas nonacclimated tips undergo severe cytoplasmic acidosis and die much more quickly. We show that the plasma membrane H+-ATPase can operate under anoxia and that net H+ extrusion increases when cytoplasmic pH falls. However, at an external pH near 6.0, H+ extrusion contributes little to cytoplasmic pH regulation. At more acidic external pH values, net H+ flux into root tips increases dramatically, leading to a decrease in cytoplasmic pH and reduced tolerance of anoxia. We present evidence that, under these conditions, H+ pumps are activated to partly offset acidosis due to H+ influx and, thereby, contribute to cytoplasmic pH regulation and tolerance of anoxia. The regulation of H+ extrusion under anoxia is discussed with respect to the acclimation response and mechanisms of intracellular pH regulation in aerobic plant cells.

Effect of acclimation to caging on nephrotoxic response of rats to uranium.

Science.gov (United States)

Damon, E G; Eidson, A F; Hobbs, C H; Hahn, F F

1986-02-01

Animal studies of the toxicity and metabolism of radionuclides and chemicals often require housing of rats in metabolism cages for excreta collection. Response of rats to toxic substances may be affected by environmental factors such as the type of cage used. Dose-response studies were conducted to assess the effects of two types of cages on the nephrotoxic response of rats to uranium from implanted refined uranium ore (yellowcake). The LD50/21 days was 6 mg of uranium ore per kilogram body weight (6 mg U/kg). The 95% confidence limit (C.L.) was 3-8 mg U/kg for rats housed in metabolism cages beginning on the day of implantation (naive rats). However, for rats housed in metabolism cages for 21 days before implantation (acclimated rats) the LD50/21 days was 360 mg U/kg (95% C.L. = 220-650 mg U/kg), which was the same value obtained for rats housed continuously in polycarbonate cages. This significant difference (P less than 0.01) in response of naive rats compared to response of acclimated rats appeared related to a significantly lower water consumption by the naive rats.

Cold Stress

Science.gov (United States)

... Publications and Products Programs Contact NIOSH NIOSH COLD STRESS Recommend on Facebook Tweet Share Compartir Workers who ... cold environments may be at risk of cold stress. Extreme cold weather is a dangerous situation that ...

Acclimation of subsurface microbial communities to mercury

DEFF Research Database (Denmark)

de Lipthay, Julia R; Rasmussen, Lasse D; Øregaard, Gunnar

2008-01-01

of mercury tolerance and functional versatility of bacterial communities in contaminated soils initially were higher for surface soil, compared with the deeper soils. However, following new mercury exposure, no differences between bacterial communities were observed, which indicates a high adaptive potential......We studied the acclimation to mercury of bacterial communities of different depths from contaminated and noncontaminated floodplain soils. The level of mercury tolerance of the bacterial communities from the contaminated site was higher than those of the reference site. Furthermore, the level...... of the subsurface communities, possibly due to differences in the availability of mercury. IncP-1 trfA genes were detected in extracted community DNA from all soil depths of the contaminated site, and this finding was correlated to the isolation of four different mercury-resistance plasmids, all belonging...

Hypersalinity Acclimation Increases the Toxicity of the Insecticide Phorate in Coho Salmon (Oncorhynchus kisutch)

Science.gov (United States)

Lavado, Ramon; Maryoung, Lindley A.; Schlenk, Daniel

2012-01-01

Previous studies in euryhaline fish have shown that acclimation to hypersaline environments enhances the toxicity of thioether organophosphate and carbamate pesticides. To better understand the potential mechanism of enhanced toxicity, the effects of the organophosphate insecticide phorate were evaluated in coho salmon (Oncorhynchus kisutch) maintained in freshwater (salinity-dependent manner. In contrast, formation of phorate-oxon (gill; olfactory tissues), phorate sulfone (liver), and phorate-oxon sulfoxide (liver; olfactory tissues) was significantly enhanced in fish acclimated to higher salinities. From previous studies, it was expected that phorate and phorate sulfoxide would be less potent AChE inhibitors than phorate-oxon, with phorate-oxon sulfoxide being the most potent of the compounds tested. This trend was confirmed in this study. In summary, these results suggest that differential expression and/or catalytic activities of Phase I enzymes may be involved to enhance phorate oxidative metabolism and subsequent toxicity of phorate to coho salmon under hypersaline conditions. The outcome may be enhanced fish susceptibility to anticholineterase oxon sulfoxides. PMID:21488666

Mapping Anomalous Democracies During the Cold War

DEFF Research Database (Denmark)

Seeberg, Michael

2014-01-01

During the Cold War, a number of countries established stable democracies despite low levels of modernization and a relative lack of democratic neighbour countries—factors otherwise consistently related to the endurance of democracy. Meanwhile, the Cold War superpowers often supported autocracies...... are identified, including Bolivia, Botswana, Colombia, Costa Rica, Dominican Republic, Honduras, India, Jamaica, Mauritius, Trinidad and Tobago, and Turkey....

Parallel Changes in H2O2 and Catalase during Thermotolerance Induced by Salicylic Acid or Heat Acclimation in Mustard Seedlings1

Science.gov (United States)

Dat, James F.; Lopez-Delgado, Humberto; Foyer, Christine H.; Scott, Ian M.

1998-01-01

Spraying mustard (Sinapis alba L.) seedlings with salicylic acid (SA) solutions between 10 and 500 μm significantly improved their tolerance to a subsequent heat shock at 55°C for 1.5 h. The effects of SA were concentration dependent, with higher concentrations failing to induce thermotolerance. The time course of thermotolerance induced by 100 μm SA was similar to that obtained with seedlings acclimated at 45°C for 1 h. We examined the hypothesis that induced thermotolerance involved H2O2. Heat shock at 55°C caused a significant increase in endogenous H2O2 and reduced catalase activity. A peak in H2O2 content was observed within 5 min of either SA treatment or transfer to the 45°C acclimation temperature. Between 2 and 3 h after SA treatment or heat acclimation, both H2O2 and catalase activity significantly decreased below control levels. The lowered H2O2 content and catalase activity occurred in the period of maximum thermoprotection. It is suggested that thermoprotection obtained either by spraying SA or by heat acclimation may be achieved by a common signal transduction pathway involving an early increase in H2O2. PMID:9536052

High-light acclimation in Quercus robur L.seedlings upon over-topped a shaded environment

Science.gov (United States)

Anna M. Jensen; Emile S. Gardiner; Kevin C. Vaughn

2012-01-01

High developmental plasticity at the seedling-level during acclimation to the light environment may be an important determinant of seedling establishment and growth in temperate broadleaf forests, especially in dense understories where spatial light availability can vary greatly. Pedunculate oak (Quercus robur L.) seedlings were raised beneath a...

Vertical and horizontal distribution of Desmophyllum dianthus in Comau Fjord, Chile: a cold-water coral thriving at low pH.

Science.gov (United States)

Fillinger, Laura; Richter, Claudio

2013-01-01

Cold-water corals provide an important habitat for a rich fauna along the continental margins and slopes. Although these azooxanthellate corals are considered particularly sensitive to ocean acidification, their responses to natural variations in pH and aragonite saturation are largely unknown due to the difficulty of studying their ecology in deep waters. Previous SCUBA investigations have shown an exceptionally shallow population of the cold-water coral Desmophyllum dianthus in near-surface waters of Comau Fjord, a stratified 480 m deep basin in northern Chilean Patagonia with suboxic deep waters. Here, we use a remotely operated vehicle to quantitatively investigate the distribution of D. dianthus and its physico-chemical drivers in so far uncharted naturally acidified waters. Remarkably, D. dianthus was ubiquitous throughout the fjord, but particularly abundant between 20 and 280 m depth in a pH range of 8.4 to 7.4. The persistence of individuals in aragonite-undersaturated waters suggests that present-day D. dianthus in Comau Fjord may show pre-acclimation or pre-adaptation to conditions of ocean acidification predicted to reach over 70% of the known deep-sea coral locations by the end of the century.

Vertical and horizontal distribution of Desmophyllum dianthus in Comau Fjord, Chile: a cold-water coral thriving at low pH

Directory of Open Access Journals (Sweden)

Laura Fillinger

2013-10-01

Full Text Available Cold-water corals provide an important habitat for a rich fauna along the continental margins and slopes. Although these azooxanthellate corals are considered particularly sensitive to ocean acidification, their responses to natural variations in pH and aragonite saturation are largely unknown due to the difficulty of studying their ecology in deep waters. Previous SCUBA investigations have shown an exceptionally shallow population of the cold-water coral Desmophyllum dianthus in near-surface waters of Comau Fjord, a stratified 480 m deep basin in northern Chilean Patagonia with suboxic deep waters. Here, we use a remotely operated vehicle to quantitatively investigate the distribution of D. dianthus and its physico-chemical drivers in so far uncharted naturally acidified waters. Remarkably, D. dianthus was ubiquitous throughout the fjord, but particularly abundant between 20 and 280 m depth in a pH range of 8.4 to 7.4. The persistence of individuals in aragonite-undersaturated waters suggests that present-day D. dianthus in Comau Fjord may show pre-acclimation or pre-adaptation to conditions of ocean acidification predicted to reach over 70% of the known deep-sea coral locations by the end of the century.

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

Czech Academy of Sciences Publication Activity Database

Hadamová, Markéta; Gvoždík, Lumír

2011-01-01

Roč. 84, č. 2 (2011), s. 166-174 ISSN 1522-2152 R&D Projects: GA ČR GAP506/10/2170; GA MŠk LC06073 Institutional research plan: CEZ:AV0Z60930519 Keywords : thermal acclimation * thermoregulatory behavior * amphibians Subject RIV: EG - Zoology Impact factor: 2.201, year: 2011 http://www.jstor.org/stable/10.1086/658202

Plant phenotyping: a perspective

Czech Academy of Sciences Publication Activity Database

Mishra, Kumud; Mishra, Anamika; Klem, Karel; Govindjee, G.

2016-01-01

Roč. 21, č. 4 (2016), s. 514-527 ISSN 0019-5502 R&D Projects: GA MŠk(CZ) LO1415; GA ČR GA13-28093S Institutional support: RVO:67179843 Keywords : Chlorophyll a fluorescence (ChlF) * Cold acclimation (CA) * Drought acclimation (DA) * Hyperspectral imaging * Infrared thermal imaging Subject RIV: EH - Ecology, Behaviour

Tracking the evolution of a cold stress associated gene family in cold tolerant grasses

DEFF Research Database (Denmark)

Sandve, Simen R; Rudi, Heidi; Asp, Torben

2008-01-01

to the repeat motifs of the IRI-domain in cold tolerant grasses. Finally we show that the LRR-domain of carrot and grass IRI proteins both share homology to an Arabidopsis thaliana LRR-trans membrane protein kinase (LRR-TPK). Conclusion The diverse IRI-like genes identified in this study tell a tale...... of a complex evolutionary history including birth of an ice binding domain, a burst of gene duplication events after cold tolerant grasses radiated from rice, protein domain structure differentiation between paralogs, and sub- and/or neofunctionalisation of IRI-like proteins. From our sequence analysis we...

Improving cold chain systems: Challenges and solutions.

Science.gov (United States)

Ashok, Ashvin; Brison, Michael; LeTallec, Yann

2017-04-19

While a number of new vaccines have been rolled out across the developing world (with more vaccines in the pipeline), cold chain systems are struggling to efficiently support national immunization programs in ensuring the availability of safe and potent vaccines. This article reflects on the Clinton Health Access Initiative, Inc. (CHAI) experience working since 2010 with national immunization programs and partners to improve vaccines cold chains in 10 countries-Ethiopia, Nigeria, Kenya, Malawi, Tanzania, Uganda, Cameroon, Mozambique, Lesotho and India - to identify the root causes and solutions for three common issues limiting cold chain performance. Key recommendations include: Collectively, the solutions detailed in this article chart a path to substantially improving the performance of the cold chain. Combined with an enabling global and in-country environment, it is possible to eliminate cold chain issues as a substantial barrier to effective and full immunization coverage over the next few years. Copyright © 2017. Published by Elsevier Ltd.

Phosphoproteome profiling for cold temperature perception.

Science.gov (United States)

Park, Seyeon; Jang, Mi

2011-02-01

Temperature sensation initiates from the activation of cellular receptors when the cell is exposed to a decrease in temperature. Here, we applied a phosphoproteome profiling approach to the human lung epithelial cell line BEAS-2B to elucidate cellular cold-responsive processes. The primary aim of this study was to determine which intracellular changes of phosphorylation are accompanied by cold sensation. Eighteen protein spots that exhibited differentially phosphorylated changes in cells were identified. Most of the proteins that were phosphorylated after 5 or 10 min were returned to control levels after 30 or 60 min. Identified proteins were mainly RNA-related (i.e., they were involved in RNA binding and splicing). Temperature (18 and 10°C) stimuli showed homologies that were detected for time course changes in phosphoproteome. The data indicated a time-shift between two temperatures. The phosphorylation of putative cold responsive markers, such as ribosomal protein large P0 and heterochromatin-associated proteins 1, were verified by Western blotting in cells transfected with TRPM8 or TRPA1. Copyright © 2010 Wiley-Liss, Inc.

Warm temperature acclimation impacts metabolism of paralytic shellfish toxins from Alexandrium minutum in commercial oysters.

Science.gov (United States)

Farrell, Hazel; Seebacher, Frank; O'Connor, Wayne; Zammit, Anthony; Harwood, D Tim; Murray, Shauna

2015-09-01

Species of Alexandrium produce potent neurotoxins termed paralytic shellfish toxins and are expanding their ranges worldwide, concurrent with increases in sea surface temperature. The metabolism of molluscs is temperature dependent, and increases in ocean temperature may influence both the abundance and distribution of Alexandrium and the dynamics of toxin uptake and depuration in shellfish. Here, we conducted a large-scale study of the effect of temperature on the uptake and depuration of paralytic shellfish toxins in three commercial oysters (Saccostrea glomerata and diploid and triploid Crassostrea gigas, n = 252 per species/ploidy level). Oysters were acclimated to two constant temperatures, reflecting current and predicted climate scenarios (22 and 27 °C), and fed a diet including the paralytic shellfish toxin-producing species Alexandrium minutum. While the oysters fed on A. minutum in similar quantities, concentrations of the toxin analogue GTX1,4 were significantly lower in warm-acclimated S. glomerata and diploid C. gigas after 12 days. Following exposure to A. minutum, toxicity of triploid C. gigas was not affected by temperature. Generally, detoxification rates were reduced in warm-acclimated oysters. The routine metabolism of the oysters was not affected by the toxins, but a significant effect was found at a cellular level in diploid C. gigas. The increasing incidences of Alexandrium blooms worldwide are a challenge for shellfish food safety regulation. Our findings indicate that rising ocean temperatures may reduce paralytic shellfish toxin accumulation in two of the three oyster types; however, they may persist for longer periods in oyster tissue. © 2015 John Wiley & Sons Ltd.

COMPARISON OF THE FROST RESISTANCE OF BARLEY ...

African Journals Online (AJOL)

Preferred Customer

immediate recovery of the photosynthetic quantum yield after freezing. Landraces which showed the highest cold tolerance were found to acclimatize best. Key words/phrases: Barley, chlorophyll fluorescence, cold acclimation, Ethiopia, frost tolerance. INTRODUCTION. Barley (Hordeum vulgare L.) is a traditional crop.

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.

Strong thermal acclimation of photosynthesis in tropical and temperate wet-forest tree species: the importance of altered Rubisco content.

Science.gov (United States)

Scafaro, Andrew P; Xiang, Shuang; Long, Benedict M; Bahar, Nur H A; Weerasinghe, Lasantha K; Creek, Danielle; Evans, John R; Reich, Peter B; Atkin, Owen K

2017-07-01

Understanding of the extent of acclimation of light-saturated net photosynthesis (A n ) to temperature (T), and associated underlying mechanisms, remains limited. This is a key knowledge gap given the importance of thermal acclimation for plant functioning, both under current and future higher temperatures, limiting the accuracy and realism of Earth system model (ESM) predictions. Given this, we analysed and modelled T-dependent changes in photosynthetic capacity in 10 wet-forest tree species: six from temperate forests and four from tropical forests. Temperate and tropical species were each acclimated to three daytime growth temperatures (T growth ): temperate - 15, 20 and 25 °C; tropical - 25, 30 and 35 °C. CO 2 response curves of A n were used to model maximal rates of RuBP (ribulose-1,5-bisphosphate) carboxylation (V cmax ) and electron transport (J max ) at each treatment's respective T growth and at a common measurement T (25 °C). SDS-PAGE gels were used to determine abundance of the CO 2 -fixing enzyme, Rubisco. Leaf chlorophyll, nitrogen (N) and mass per unit leaf area (LMA) were also determined. For all species and T growth , A n at current atmospheric CO 2 partial pressure was Rubisco-limited. Across all species, LMA decreased with increasing T growth . Similarly, area-based rates of V cmax at a measurement T of 25 °C (V cmax 25 ) linearly declined with increasing T growth , linked to a concomitant decline in total leaf protein per unit leaf area and Rubisco as a percentage of leaf N. The decline in Rubisco constrained V cmax and A n for leaves developed at higher T growth and resulted in poor predictions of photosynthesis by currently widely used models that do not account for T growth -mediated changes in Rubisco abundance that underpin the thermal acclimation response of photosynthesis in wet-forest tree species. A new model is proposed that accounts for the effect of T growth -mediated declines in V cmax 25 on A n , complementing current

Effect of acclimation medium on cell viability, membrane integrity and ability to consume malic acid in synthetic wine by oenological Lactobacillus plantarum strains.

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

2014-02-01

The aim of this work was to evaluate the effect of acclimation on the viability, membrane integrity and the ability to consume malic acid of three oenological strains of Lactobacillus plantarum. Cultures in the stationary phase were inoculated in an acclimation medium (Accl.) containing 0, 6 or 10% v/v ethanol and incubated 48 h at 28°C. After incubation, cells were harvested by centrifugation and inoculated in a synthetic wine, containing 14% v/v ethanol and pH 3.5 at 28°C. Viability and membrane integrity were determined by flow cytometry (FC) using carboxyfluorescein diacetate (cFDA) and propidium iodide. Bacterial growth and malic acid consumption were monitored in a synthetic wine during 15 days. In nonacclimated strains, the damage of bacterial membranes produced a dramatic decrease in microbial viability in synthetic wine. In contrast, survival of strains previously acclimated in Accl. with 6 and 10% v/v ethanol was noticeable higher. Therefore, acclimation with ethanol increased the cultivability in synthetic wine and consequently, the consumption of l-malic acid after 15 days of growth. Acclimation of oenological strains in media containing ethanol prior to wine inoculation significantly decreases the membrane damage and improves viability in the harsh wine conditions. The role of membrane integrity is crucial to warrant the degradation of l-malic acid. The efficiency of multiparametric FC in monitoring viability and membrane damage along with the malic acid consumption has a strong impact on winemaking because it represents a useful tool for a quick and highly reliable evaluation of oenological parameters. © 2013 The Society for Applied Microbiology.

Expression of aquaporin 3 in gills of the Atlantic killifish (Fundulus heteroclitus): Effects of seawater acclimation

Science.gov (United States)

Jung, Dawoon; Sato, J. Denry; Shaw, Joseph R.; Stanton, Bruce A.

2011-01-01

Estuarine fish, such as the Atlantic killifish (Fundulus heteroclitus), are constantly and rapidly exposed to changes in salinity. Although ion transport in killifish gills during acclimation to increased salinity has been studied extensively, no studies have examined the role of aquaglyceroporin 3 (AQP3), a water, glycerol, urea, and ammonia transporter, during acclimation to increased salinity in this sentinel environmental model organism. The goal of this study was to test the hypothesis that transfer from freshwater to seawater decreases AQP3 gene and protein expression in the gill of killifish. Transfer from freshwater to seawater decreased AQP3 mRNA in the gill after 1 day, but had no effect on total gill AQP3 protein abundance as determined by western blot. Quantitative confocal immunocytochemistry confirmed western blot studies that transfer from freshwater to seawater did not change total AQP3 abundance in the gill; however, immunocytochemistry revealed that the amount of AQP3 in pillar cells of secondary lamellae decreased in seawater fish, whereas the amount of AQP3 in mitochondrion rich cells (MRC) in primary filaments of the gill increased in seawater fish. This response of AQP3 expression is unique to killifish compared to other teleosts. Although the role of AQP3 in the gill of killifish has not been completely elucidated, these results suggest that AQP3 may play an important role in the ability of killifish to acclimate to increased salinity. PMID:22193757

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

Subcellular pigment distribution is altered under far-red light acclimation in cyanobacteria that contain chlorophyll f.

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Majumder, Erica L-W; Wolf, Benjamin M; Liu, Haijun; Berg, R Howard; Timlin, Jerilyn A; Chen, Min; Blankenship, Robert E

2017-11-01

Far-Red Light (FRL) acclimation is a process that has been observed in cyanobacteria and algae that can grow solely on light above 700 nm. The acclimation to FRL results in rearrangement and synthesis of new pigments and pigment-protein complexes. In this study, cyanobacteria containing chlorophyll f, Synechococcus sp. PCC 7335 and Halomicronema hongdechloris, were imaged as live cells with confocal microscopy. H. hongdechloris was further studied with hyperspectral confocal fluorescence microscopy (HCFM) and freeze-substituted thin-section transmission electron microscopy (TEM). Under FRL, phycocyanin-containing complexes and chlorophyll-containing complexes were determined to be physically separated and the synthesis of red-form phycobilisome and Chl f was increased. The timing of these responses was observed. The heterogeneity and eco-physiological response of the cells was noted. Additionally, a gliding motility for H. hongdechloris is reported.

Cold injuries.

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Kruse, R J

1995-01-01

There are two categories of cold injury. The first is hypothermia, which is a systemic injury to cold, and the second is frostbite, which is a local injury. Throughout history, entire armies, from George Washington to the Germans on the Russian Front in World War II, have fallen prey to prolonged cold exposure. Cold injury is common and can occur in all seasons if ambient temperature is lower than the core body temperature. In the 1985 Boston Marathon, even though it was 76 degrees and sunny, there were 75 runners treated for hypothermia. In general, humans adapt poorly to cold exposure. Children are at particular risk because of their relatively greater surface area/body mass ratio, causing them to cool even more rapidly than adults. Because of this, the human's best defense against cold injury is to limit his/her exposure to cold and to dress appropriately. If cold injury has occurred and is mild, often simple passive rewarming such as dry blankets and a warm room are sufficient treatment.

Chloroplast osmotic adjustment allows for acclimation of photosynthesis to low water potentials

International Nuclear Information System (INIS)

Gupta, A.S.; Berkowitz, G.

1987-01-01

Previously in this laboratory, studies indicated that photosynthesis (PS) of chloroplasts isolated from spinach plants which underwent osmotic adjustment during in situ water deficits was inhibited less at low osmotic potentials (Psi/sub s/) in vitro than PS of plastids isolated from well watered plants. In this study, an attempt was made to determine if chloroplast acclimation to low Psi/sub s/ was associated with in situ stromal solute accumulation. During a 14d stress cycle, in situ stromal volume was estimated by measuring (using the 3 H 2 O, 14 C-sorbitol silicon oil centrifugation technique) the stromal space of plastids in solutions which had the Psi/sub s/ adjusted to the leaf Psi/sub s/. During the first lid of the cycle, stromal volume did not decline, despite a decrease of over 20% in the leaf RWC. After this time, stromal volume dropped rapidly. In situ stromal Psi/sub s/ was also estimated during a stress cycle. These studies indicated that stromal Psi/sub s/ was lowered by net solute accumulation. The data presented in this report suggest that chloroplast acclimation to low Psi/sub s/ may involve stromal solute accumulation and volume maintenance during cell water loss

Deep sequencing of Brachypodium small RNAs at the global genome level identifies microRNAs involved in cold stress response

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Chong Kang

2009-09-01

Full Text Available Abstract Background MicroRNAs (miRNAs are endogenous small RNAs having large-scale regulatory effects on plant development and stress responses. Extensive studies of miRNAs have only been performed in a few model plants. Although miRNAs are proved to be involved in plant cold stress responses, little is known for winter-habit monocots. Brachypodium distachyon, with close evolutionary relationship to cool-season cereals, has recently emerged as a novel model plant. There are few reports of Brachypodium miRNAs. Results High-throughput sequencing and whole-genome-wide data mining led to the identification of 27 conserved miRNAs, as well as 129 predicted miRNAs in Brachypodium. For multiple-member conserved miRNA families, their sizes in Brachypodium were much smaller than those in rice and Populus. The genome organization of miR395 family in Brachypodium was quite different from that in rice. The expression of 3 conserved miRNAs and 25 predicted miRNAs showed significant changes in response to cold stress. Among these miRNAs, some were cold-induced and some were cold-suppressed, but all the conserved miRNAs were up-regulated under cold stress condition. Conclusion Our results suggest that Brachypodium miRNAs are composed of a set of conserved miRNAs and a large proportion of non-conserved miRNAs with low expression levels. Both kinds of miRNAs were involved in cold stress response, but all the conserved miRNAs were up-regulated, implying an important role for cold-induced miRNAs. The different size and genome organization of miRNA families in Brachypodium and rice suggest that the frequency of duplication events or the selection pressure on duplicated miRNAs are different between these two closely related plant species.

Assimilation of water and dietary ions by the gastrointestinal tract during digestion in seawater-acclimated rainbow trout.

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Bucking, Carol; Fitzpatrick, John L; Nadella, Sunita R; McGaw, Iain J; Wood, Chris M

2011-07-01

Recent studies focusing on the consequences of feeding for ion and water balance in freshwater fish have revealed the need for similar comparative studies in seawater fish. A detailed time course sampling of gastrointestinal (GI) tract contents following the ingestion of a single meal of a commercial diet revealed the assimilation of both water and dietary ions (Na(+), Cl(-), K(+), Ca(2+), Mg(2+)) along the GI tract of seawater-acclimated rainbow trout (Oncorhynchus mykiss) which had been fasted for 1 week. Consumption of the meal did not change the drinking rate. There was a large secretion of fluid into the anterior intestine and caecae (presumably bile and/or pancreatic secretions). As a result, net assimilation (63%) of the ingested water along the GI tract was lower than generally reported for fasted trout. Mg(2+) was neither secreted into nor absorbed from the GI tract on a net basis. Only K(+) (93% assimilated) and Ca(2+) (43% assimilated) were absorbed in amounts in excess of those provided by ingested seawater, suggesting that dietary sources of K(+) and Ca(2+) may be important to seawater teleosts. The oesophagus-stomach served as a major site of absorption for Na(+), Cl(-), K(+), Ca(2+), and Mg(2+), and the anterior intestine and caecae as a major site of net secretion for all of these ions, except Cl(-). Despite large absorptive fluxes of these ions, the ionic composition of the plasma was maintained during the digestion of the meal. The results of the present study were compared with previous work on freshwater-acclimated rainbow trout, highlighting some important differences, but also several similarities on the assimilation of water and ions along the gastrointestinal tract during digestion. This study highlights the complicated array of ion and water transport that occurs in the intestine during digestion while revealing the importance of dietary K(+) and Ca(2+) to seawater-acclimated rainbow trout. Additionally, this study reveals that digestion

NH4+ protects tomato plants against Pseudomonas syringae by activation of systemic acquired acclimation.

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Fernández-Crespo, Emma; Scalschi, Loredana; Llorens, Eugenio; García-Agustín, Pilar; Camañes, Gemma

2015-11-01

NH4 (+) nutrition provokes mild toxicity by enhancing H2O2 accumulation, which acts as a signal activating systemic acquired acclimation (SAA). Until now, induced resistance mechanisms in response to an abiotic stimulus and related to SAA were only reported for exposure to a subsequent abiotic stress. Herein, the first evidence is provided that this acclimation to an abiotic stimulus induces resistance to later pathogen infection, since NH4 (+) nutrition (N-NH4 (+))-induced resistance (NH4 (+)-IR) against Pseudomonas syringae pv tomato DC3000 (Pst) in tomato plants was demonstrated. N-NH4 (+) plants displayed basal H2O2, abscisic acid (ABA), and putrescine (Put) accumulation. H2O2 accumulation acted as a signal to induce ABA-dependent signalling pathways required to prevent NH4 (+) toxicity. This acclimatory event provoked an increase in resistance against later pathogen infection. N-NH4 (+) plants displayed basal stomatal closure produced by H2O2 derived from enhanced CuAO and rboh1 activity that may reduce the entry of bacteria into the mesophyll, diminishing the disease symptoms as well as strongly inducing the oxidative burst upon Pst infection, favouring NH4 (+)-IR. Experiments with inhibitors of Put accumulation and the ABA-deficient mutant flacca demonstrated that Put and ABA downstream signalling pathways are required to complete NH4 (+)-IR. The metabolic profile revealed that infected N-NH4 (+) plants showed greater ferulic acid accumulation compared with control plants. Although classical salicylic acid (SA)-dependent responses against biotrophic pathogens were not found, the important role of Put in the resistance of tomato against Pst was demonstrated. Moreover, this work revealed the cross-talk between abiotic stress acclimation (NH4 (+) nutrition) and resistance to subsequent Pst infection. © The Author 2015. Published by Oxford University Press on behalf of the Society for Experimental Biology.

Post-prandial metabolic alkalosis in the seawater-acclimated trout: the alkaline tide comes in.

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Bucking, Carol; Fitzpatrick, John L; Nadella, Sunita R; Wood, Chris M

2009-07-01

The consequences of feeding and digestion on acid-base balance and regulation in a marine teleost (seawater-acclimated steelhead trout; Oncorhynchus mykiss) were investigated by tracking changes in blood pH and [HCO3-], as well as alterations in net acid or base excretion to the water following feeding. Additionally the role of the intestine in the regulation of acid-base balance during feeding was investigated with an in vitro gut sac technique. Feeding did not affect plasma glucose or urea concentrations, however, total plasma ammonia rose during feeding, peaking between 3 and 24 h following the ingestion of a meal, three-fold above resting control values (approximately 300 micromol ml(-1)). This increase in plasma ammonia was accompanied by an increase in net ammonia flux to the water (approximately twofold higher in fed fish versus unfed fish). The arterial blood also became alkaline with increases in pH and plasma [HCO3-] between 3 and 12 h following feeding, representing the first measurement of an alkaline tide in a marine teleost. There was no evidence of respiratory compensation for the measured metabolic alkalosis, as Pa CO2 remained unchanged throughout the post-feeding period. However, in contrast to an earlier study on freshwater-acclimated trout, fed fish did not exhibit a compensating increase in net base excretion, but rather took in additional base from the external seawater, amounting to approximately 8490 micromol kg(-1) over 48 h. In vitro experiments suggest that at least a portion of the alkaline tide was eliminated through increased HCO3- secretion coupled to Cl- absorption in the intestinal tract. This did not occur in the intestine of freshwater-acclimated trout. The marked effects of the external salinity (seawater versus freshwater) on different post-feeding patterns of acid-base balance are discussed.

Worldwide variation in within-canopy photosynthetic acclimation: differences in temporal and environmental controls among plant functional types

Science.gov (United States)

Niinemets, Ülo; Keenan, Trevor

2017-04-01

Major light gradients, characteristically 10- to 50-fold, constitute the most prominent feature of plant canopies. These gradients drive within-canopy variation in foliage structural, chemical and physiological traits. As a key acclimation response to variation in light availability, foliage photosynthetic capacity per area (Aarea) increases with increasing light availability within the canopy, maximizing whole canopy photosynthesis. Recently, a worldwide database including 831 within-canopy gradients with standardized light estimates for 304 species belonging to major vascular plant functional types was constructed and within-canopy variation in photosynthetic acclimation was characterized (Niinemets Ü, Keenan TF, Hallik L (2015) Tansley review. A worldwide analysis of within-canopy variations in leaf structural, chemical and physiological traits across plant functional types. The New Phytologist 205: 973-993). However, the understanding of how within-canopy photosynthetic gradients vary during the growing season and in response to site and stand characteristics is still limited. Here we analyzed temporal, environmental and site (nutrient availability, stand density, ambient CO2 concentration, water availability) sources of variation in within-canopy photosynthetic acclimation in different plant functional types. Variation in key structural (leaf dry mass per unit area, MA), chemical (nitrogen content per dry mass, NM, and area, NA) and physiological (photosynthetic nitrogen use efficiency, EN) photosynthetic capacity per dry mass, Amass and area, Aarea) was examined. The analysis demonstrates major, typically 1.5-2-fold, time-, environment and site-dependent modifications in within-canopy variation in foliage photosynthetic capacity. However, the magnitude and direction of temporal and environmental variations in plasticity significantly varied among functional types. Species with longer leaf life span and low rates of canopy expansion or flush-type canopy

Effects of temperament and acclimation to handling on feedlot performance of Bos taurus feeder cattle originated from a rangeland-based cow-calf system.

Science.gov (United States)

Francisco, C L; Cooke, R F; Marques, R S; Mills, R R; Bohnert, D W

2012-12-01

Two experiments evaluated the effects of temperament and acclimation to handling on performance of Angus × Hereford feeder cattle reared in extensive rangeland systems until weaning. In Exp. 1, 200 calves (n = 97 for yr 1; n = 103 for yr 2) were evaluated for temperament at weaning (average age ± SE = 152 ± 1 d) by chute score and exit velocity. Chute score was assessed on a 5-point scale according to behavior during chute restraining. Exit score was calculated by dividing exit velocity into quintiles and assigning calves a score from 1 (slowest) to 5 (fastest). A temperament score was calculated for each calf by averaging chute and exit scores. Calf temperament was classified according to temperament score as adequate (≤3) or excitable (>3). After weaning, calves were assigned to a 40-d preconditioning followed by growing (139 d) and finishing (117 d) phases until slaughter. Weaning BW was decreased (P = 0.04) in excitable calves compared with adequate calves. No differences were detected (P ≥ 0.21) for ADG during preconditioning, growing, and finishing phases; hence, excitable calves tended (P = 0.09) to have decreased HCW compared with adequate calves. In Exp. 2, 60 steers (initial age ± SE = 198 ± 2 d) were weighed and evaluated for temperament score 35 d after weaning (d -29). On d -28, steers were ranked by these variables and assigned to receive an acclimation treatment or not (control). Acclimated steers were processed through a handling facility twice weekly for 4 wk (d -28 to -1) whereas control steers remained undisturbed on pasture. On d 0, all steers were transported for 24 h and returned to the research facility (d 1). On arrival, steers were ranked by BW within treatment and randomly assigned to 20 feedlot pens for a 28-d feedlot receiving period. Acclimated steers had decreased temperament score and plasma cortisol compared with controls on d 0 (P = 0.02). During feedlot receiving, acclimated steers had decreased ADG (P < 0.01) and G:F (P

Limited capacity for developmental thermal acclimation in three tropical wrasses

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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.

Production of cold antihydrogen in a nested trap

International Nuclear Information System (INIS)

Fujiwara, Makoto

2004-01-01

The ATHENA experiment at CERN produced and detected the first cold antihydrogen atoms. Antiprotons and positrons are mixed in a double Penning trap, known as a nested trap. The production of antihydrogen atoms was identified by detecting their annihilations signatures at trap wall. With the ATHENA results subsequently confirmed by another CERN experiment, ATRAP, cold antihydrogen research is entering an exciting era. (author)

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

Lostine River spring Chinook salmon smolts occurred from March 3, 2003 through to April 14, 2003 and a total of 242,776 smolts were acclimated and released. These smolts were produced from the brood year (BY) 2001 egg source and included captive broodstock (141,860) and conventional broodstock (100,916) origin smolts that were all progeny of Lostine River spring Chinook salmon. Operation of the Lostine River adult monitoring and collection facility in 2003 began April 30th, the first Chinook was captured on May 16, 2003 and the last Chinook was captured on September 21, 2003. The weir and trap were removed on October 1, 2003. A total of 464 adult Chinook, including jacks, were captured during the season. The composition of the run included 239 natural origin fish and 225 hatchery supplementation fish. There were no identified 'stray' hatchery fish from other programs trapped. Of the fish captured, 45 natural and 4 hatchery supplementation adults were retained for broodstock and transported to LGH for holding and spawning, 366 adult Chinook were passed or transported above the weir to spawn naturally, and 49 hatchery origin adult jack Chinook were transported and outplanted in the Wallowa River and Bear Creek to spawn in underseeded habitat. Of the 49 adults retained for broodstock at Lookingglass Hatchery, 21 natural females and no hatchery origin females were represented in spawning. These females produced a total of 106,609 eggs at fertilization. Eye-up was 95.50% which yielded a total of 101,811 conventional program eyed eggs. The fecundity averaged 5,077 eggs per female. These eggs were incubated and at Lookingglass Hatchery until eyed stage. At eye they were transferred to Oxbow Hatchery where they were reared to the fingerling state at which time they were transported back to LGH until they were smolts in the spring of 2005. Captive brood program eggs/fish will be added to the conventional program eggs to make up the entire juvenile release for the Lostine

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

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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 ma...

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.

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

Cold Pain Threshold Identifies a Subgroup of Individuals With Knee Osteoarthritis That Present With Multimodality Hyperalgesia and Elevated Pain Levels

OpenAIRE

Wright, Anthony; Benson, Heather A.E.; Will, Rob; Moss, Penny

2017-01-01

Objectives: Cold hyperalgesia has been established as an important marker of pain severity in a number of conditions. This study aimed to establish the extent to which patients with knee osteoarthritis (OA) demonstrate widespread cold, heat, and pressure hyperalgesia. OA participants with widespread cold hyperalgesia were compared with the remaining OA cohort to determine whether they could be distinguished in terms of hyperalgesia, pain report, pain quality, and physical function. Methods: A...

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

Physiological acclimation to drought stress in Solidago canadensis.

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Nolf, Markus; Pagitz, Konrad; Mayr, Stefan

2014-04-01

Solidago canadensis is an invasive species from North America that is spreading across Europe, Australia and temperate Asia. We hypothesized that the species' wide ecological amplitude is also based on its potential in hydraulic acclimation, and analyzed hydraulic and anatomical properties along a transect with decreasing soil humidity. Stem hydraulic conductivity, vulnerability to drought-induced embolism, stomatal closure during dehydration and xylem-anatomical parameters were quantified at three sites. At the humid site, specific hydraulic conductivity of stems (1.0 ± 0.2 kg m(-1)  MPa(-1)  s(-1)) was about twofold higher, and leaf-specific conductivity about 1.5 times higher (3.1 ± 0.5 kg m(-1)  MPa(-1)  s(-1)) than at the dry site. Water potential (Ψ) at 50% loss of conductivity was -3.7 ± 0.1 MPa at the dry site and -3.1 ± 0.2 MPa at the humid site (September). Vulnerability to drought-induced embolism decreased along the transect and over the vegetation period. At drier sites, stomata started closing at lower Ψ while complete stomatal closure was reached at less negative Ψ (12% of maximum stomatal conductance: -2.5 ± 0.0 and -3.0 ± 0.2 MPa at the dry and humid site). The safety margin between stomatal closure and 50% loss of conductivity was 1.2 and 0.2 MPa at the dry and humid sites. The observed variability indicated an efficient acclimation in hydraulic conductivity and safety: plants at dry sites exhibited lower specific hydraulic conductivity, higher embolism resistance and broader safety margins, signifying a trade-off between the hydraulic safety and efficiency. The observed intraspecific plasticity in hydraulic and anatomical traits may help to explain the invasive potential of this species. © 2013 Scandinavian Plant Physiology Society.

Photosynthetic acclimation in relation to nitrogen allocation in cucumber leaves in response to changes in irradiance

NARCIS (Netherlands)

Trouwborst, G.; Hogewoning, S.W.; Harbinson, J.; Ieperen, van W.

2011-01-01

Leaves deep in canopies can suddenly be exposed to increased irradiances following e.g. gap formation in forests or pruning in crops. Studies on the acclimation of photosynthesis to increased irradiance have mainly focused on the changes in photosynthetic capacity (Amax), although actual irradiance

Food restriction attenuates oxidative stress in brown adipose tissue of striped hamsters acclimated to a warm temperature.

Science.gov (United States)

Zhang, Ji-Ying; Zhao, Xiao-Ya; Wang, Gui-Ying; Wang, Chun-Ming; Zhao, Zhi-Jun

2016-05-01

It has been suggested that the up-regulation of uncoupling proteins (UCPs) decreases reactive oxygen species (ROS) production, in which case there should be a negative relationship between UCPs expression and ROS levels. In this study, the effects of temperature and food restriction on ROS levels and metabolic rate, UCP1 mRNA expression and antioxidant levels were examined in the brown adipose tissue (BAT) of the striped hamsters (Cricetulus barabensis). The metabolic rate and food intake of hamsters which had been restricted to 80% of ad libitum food intake, and acclimated to a warm temperature (30°C), decreased significantly compared to a control group. Hydrogen peroxide (H2O2) levels were 42.9% lower in food restricted hamsters than in the control. Malonadialdehyde (MDA) levels of hamsters acclimated to 30°C that were fed ad libitum were significantly higher than those of the control group, but 60.1% lower than hamsters that had been acclimated to the same temperature but subject to food restriction. There were significantly positive correlations between H2O2 and, MDA levels, catalase activity, and total antioxidant capacity. Cytochrome c oxidase activity and UCP1 mRNA expression significantly decreased in food restricted hamsters compared to the control. These results suggest that warmer temperatures increase oxidative stress in BAT by causing the down-regulation of UCP1 expression and decreased antioxidant activity, but food restriction may attenuate the effects. Copyright © 2016 Elsevier Ltd. All rights reserved.

Efficacy of zinc against common cold viruses: an overview.

Science.gov (United States)

Hulisz, Darrell

2004-01-01

To review the laboratory and clinical evidence of the medicinal value of zinc for the treatment of the common cold. Published articles identified through Medline (1980-2003) using the search terms zinc, rhinovirus, and other pertinent subject headings. Additional sources were identified from the bibliographies of the retrieved articles. By the author. By the author. Human rhinoviruses, by attaching to the nasal epithelium via the intracellular adhesion molecule-1 (ICAM-1) receptor, cause most colds. Ionic zinc, based on its electrical charge, also has an affinity for ICAM-1 receptor sites and may exert an antiviral effect by attaching to the ICAM-1 receptors in the rhinovirus structure and nasal epithelial cells. Clinical tests of zinc for treatment of common colds have been inconsistent, primarily because of study design, blinding, and lozenge contents. Early formulations of lozenges also were unpalatable. In three trials with similar study designs, methodologies, and efficacy assessments, zinc effectively and significantly shortened the duration of the common cold when it was administered within 24 hours of the onset of symptoms. Recent reports of trials with zinc gluconate administered as a nasal gel have supported these findings; in addition, they have shown that treatment with zinc nasal gel is effective in reducing the duration and severity of common cold symptoms in patients with established illness. Clinical trial data support the value of zinc in reducing the duration and severity of symptoms of the common cold when administered within 24 hours of the onset of common cold symptoms. Additional clinical and laboratory evaluations are warranted to further define the role of ionic zinc for the prevention and treatment of the common cold and to elucidate the biochemical mechanisms through which zinc exerts its symptom-relieving effects.

Materials for cold neutron sources: Cryogenic and irradiation effects

International Nuclear Information System (INIS)

Alexander, D.J.

1990-01-01

Materials for the construction of cold neutron sources must satisfy a range of demands. The cryogenic temperature and irradiation create a severe environment. Candidate materials are identified and existing cold sources are briefly surveyed to determine which materials may be used. Aluminum- and magnesium-based alloys are the preferred materials. Existing data for the effects of cryogenic temperature and near-ambient irradiation on the mechanical properties of these alloys are briefly reviewed, and the very limited information on the effects of cryogenic irradiation are outlined. Generating mechanical property data under cold source operating conditions is a daunting prospect. It is clear that the cold source material will be degraded by neutron irradiation, and so the cold source must be designed as a brittle vessel. The continued effective operation of many different cold sources at a number of reactors makes it clear that this can be accomplished. 46 refs., 8 figs., 2 tab

Cold plate

Energy Technology Data Exchange (ETDEWEB)

Marroquin, Christopher M.; O' Connell, Kevin M.; Schultz, Mark D.; Tian, Shurong

2018-02-13

A cold plate, an electronic assembly including a cold plate, and a method for forming a cold plate are provided. The cold plate includes an interface plate and an opposing plate that form a plenum. The cold plate includes a plurality of active areas arranged for alignment over respective heat generating portions of an electronic assembly, and non-active areas between the active areas. A cooling fluid flows through the plenum. The plenum, at the non-active areas, has a reduced width and/or reduced height relative to the plenum at the active areas. The reduced width and/or height of the plenum, and exterior dimensions of cold plate, at the non-active areas allow the non-active areas to flex to accommodate surface variations of the electronics assembly. The reduced width and/or height non-active areas can be specifically shaped to fit between physical features of the electronics assembly.

Higher plants and UV-B radiation: balancing damage, repair and acclimation

International Nuclear Information System (INIS)

Jansen, M.A.K.; Gaba, V.; Greenberg, B.M.

1998-01-01

Although UV-B is a minor component of sunlight, it has a disproportionately damaging effect on higher plants. Ultraviolet-sensitive targets include DNA, proteins and membranes, and these must be protected for normal growth and development. DNA repair and secondary metabolite accumulation during exposure to UV-B have been characterized in considerable detail, but little is known about the recovery of photosynthesis, induction of free-radical scavenging and morphogenic changes. A future challenge is to elucidate how UV-B-exposed plants balance damage, repair, acclimation and adaptation responses in a photobiologically dynamic environment. (author)

Acclimation of Norway spruce photosynthetic apparatus to the combined effect of high irradiance and temperature

Czech Academy of Sciences Publication Activity Database

Štroch, M.; Vrábl, D.; Podolinská, J.; Kalina, J.; Urban, Otmar; Špunda, V.

2010-01-01

Roč. 167, č. 8 (2010), s. 597-605 ISSN 0176-1617 R&D Projects: GA ČR GA522/07/0759 Institutional research plan: CEZ:AV0Z60870520 Keywords : diurnal courses * picea abies * thermal acclimation * thermal energy dissipation * xanthophyll cycle Subject RIV: ED - Physiology Impact factor: 2.677, year: 2010

Overexpression of WsSGTL1 Gene of Withania somnifera Enhances Salt Tolerance, Heat Tolerance and Cold Acclimation Ability in Transgenic Arabidopsis Plants

Science.gov (United States)

Mishra, Manoj K.; Chaturvedi, Pankaj; Singh, Ruchi; Singh, Gaurav; Sharma, Lokendra K.; Pandey, Vibha; Kumari, Nishi; Misra, Pratibha

2013-01-01

Background Sterol glycosyltrnasferases (SGT) are enzymes that glycosylate sterols which play important role in plant adaptation to stress and are medicinally important in plants like Withania somnifera. The present study aims to find the role of WsSGTL1 which is a sterol glycosyltransferase from W. somnifera, in plant’s adaptation to abiotic stress. Methodology The WsSGTL1 gene was transformed in Arabidopsis thaliana through Agrobacterium mediated transformation, using the binary vector pBI121, by floral dip method. The phenotypic and physiological parameters like germination, root length, shoot weight, relative electrolyte conductivity, MDA content, SOD levels, relative electrolyte leakage and chlorophyll measurements were compared between transgenic and wild type Arabidopsis plants under different abiotic stresses - salt, heat and cold. Biochemical analysis was done by HPLC-TLC and radiolabelled enzyme assay. The promoter of the WsSGTL1 gene was cloned by using Genome Walker kit (Clontech, USA) and the 3D structures were predicted by using Discovery Studio Ver. 2.5. Results The WsSGTL1 transgenic plants were confirmed to be single copy by Southern and homozygous by segregation analysis. As compared to WT, the transgenic plants showed better germination, salt tolerance, heat and cold tolerance. The level of the transgene WsSGTL1 was elevated in heat, cold and salt stress along with other marker genes such as HSP70, HSP90, RD29, SOS3 and LEA4-5. Biochemical analysis showed the formation of sterol glycosides and increase in enzyme activity. When the promoter of WsSGTL1 gene was cloned from W. somnifera and sequenced, it contained stress responsive elements. Bioinformatics analysis of the 3D structure of the WsSGTL1 protein showed functional similarity with sterol glycosyltransferase AtSGT of A. thaliana. Conclusions Transformation of WsSGTL1 gene in A. thaliana conferred abiotic stress tolerance. The promoter of the gene in W.somnifera was found to have stress

Cell physiology of plants growing in cold environments.

Science.gov (United States)

Lütz, Cornelius

2010-08-01

UV. Thus, their defense and antioxidant role dominates. Ultrastructural comparisons were unable to find special light adaptations in plants taken from polar regions vs. high alpine species. The only adaptation found at the subcellular level for most alpine and polar plants are protrusions of the chloroplast envelopes. They are seen as a demand for fast membrane transport requiring additional membrane surface area, whereby the increase in stroma volume may help to support carbohydrate formation. Plants forming such protrusions have to cope with a short vegetation time. These observations are connected to the question as to how photosynthesis works quite well even at or under zero temperatures. The interplay between plastids, mitochondria, and peroxisomes, known as photorespiration, seems to be more intense than in lowland plants. This organelle cooperation serves as a valve for a surplus in solar energy input under cold conditions. Additional metabolic acclimations are under investigation, such as the role of an alternative plastid terminal oxidase. Plants from cold environments may also be seen as ideal objects for studying the combined effects of high light plus cold resistance-from the molecular level to the whole plant adaptation. Modern instrumentation makes it possible to perform vital metabolic measurements under outdoor conditions, and research stations in remote polar and alpine areas provide support for scientists in the preparation of samples for later cellular studies in the home laboratory.

Perception of foot temperature in young women with cold constitution: analysis of skin temperature and warm and cold sensation thresholds.

Science.gov (United States)

Sadakata, Mieko; Yamada, Yoshiaki

2007-06-01

To examine the disease state of cold constitution, physiological measurements of the foot were conducted by investigating thermal sensations under an environmental condition of 25 degrees C-26 degrees C (neutral temperature) in 29 young women with and without cold constitution. The subjects were classified into 3 groups according to their experiences with cold constitution: cold constitution, intermediate, and normal groups. Foot skin temperature was measured by thermography. Thermal sensations were measured on the dorsum of the left foot using a thermal stimulator. Cold and warm spots on the dorsum of the right foot were ascertained. Thermal stimulation was delivered by a copper probe. No significant differences in foot skin temperature among these 3 groups were identified as measured in a laboratory under neutral temperature conditions. However, the mean warm sensation threshold was +6.3+/-1.09 degrees C (mean+/-SEM) for the cold constitution group (n=14), +3.4+/-2.10 degrees C (mean+/-SEM) for the intermediate group (n=7), and -0.25+/-1.96 degrees C (mean+/-SEM) for the normal group (n=6). The difference was significant between the cold constitution and normal groups. No significant differences among the 3 groups were found in the cold sensation threshold. This may be attributable to the distribution of thermal receptors and to chronically reduced blood flow in subcutaneous tissues, where the skin temperature receptors responsible for temperature sensation are located.

Dissecting long-term adjustments of photoprotective and photo-oxidative stress acclimation occurring in dynamic light environments

Directory of Open Access Journals (Sweden)

Shizue Matsubara

2016-11-01

Full Text Available Changes in light intensity directly affect the performance of the photosynthetic apparatus. Light energy absorbed in excess of cells’ needs leads to production of reactive oxygen species and photo-oxidative damage. Excess light in both constant and dynamic environments induces photoprotective acclimation in plants. Distinct sets of signals and regulatory mechanisms are involved in acclimatory adjustment of photoprotection and photosynthesis under constant and dynamic (fluctuating light conditions. We are still far away from drawing a comprehensive picture of acclimatory signal transduction pathways, particularly in dynamic environments. In this perspective article, we propose the use of Arabidopsis plants that produce H2O2 in chloroplasts (GO plants under atmospheric CO2 levels as a tool to study the mechanisms of long-term acclimation to photo-oxidative stress. In our opinion there are new avenues to future investigations on acclimatory adjustments and signal transduction occurring in plants under dynamic light environments.

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

Sustainable construction in remote cold regions.

Science.gov (United States)

2015-12-01

The goal of this project was to identify sustainable construction techniques appropriate for remote and cold regions, some of which apply to : operations and maintenance as well. The vast body of literature regarding green construction in warm region...

Introduction: the human sciences and Cold War America.

Science.gov (United States)

Isaac, Joel

2011-01-01

Studies of the history of the human sciences during the Cold War era have proliferated over the past decade--in JHBS and elsewhere. This special issue focuses on the connections between the behavioral sciences and the culture and politics of the Cold War in the United States. In the recent literature, there is a tendency to identify the Cold War human sciences with two main paradigms: that of psychocultural analysis, on the one hand, and of the systems sciences, on the other. The essays in the special issue both extend understanding of each of these interpretive frameworks and help us to grasp their interconnection. © 2011 Wiley Periodicals, Inc.

Conceptualizing Cold Disasters

DEFF Research Database (Denmark)

Lauta, Kristian Cedervall; Dahlberg, Rasmus; Vendelø, Morten Thanning

2017-01-01

In the present article, we explore in more depth the particular circumstances and characteristics of governing what we call ‘cold disasters’, and thereby, the paper sets out to investigate how disasters in cold contexts distinguish themselves from other disasters, and what the implications hereof...... are for the conceptualization and governance of cold disasters. Hence, the paper can also be viewed as a response to Alexander’s (2012a) recent call for new theory in the field of disaster risk reduction. The article is structured in four overall parts. The first part, Cold Context, provides an overview of the specific...... conditions in a cold context, exemplified by the Arctic, and zooms in on Greenland to provide more specific background for the paper. The second part, Disasters in Cold Contexts, discusses “cold disasters” in relation to disaster theory, in order to, elucidate how cold disasters challenge existing...

AP2/EREBP transcription factors are part of gene regulatory networks and integrate metabolic, hormonal and environmental signals in stress acclimation and retrograde signalling.

Science.gov (United States)

Dietz, Karl-Josef; Vogel, Marc Oliver; Viehhauser, Andrea

2010-09-01

To optimize acclimation responses to environmental growth conditions, plants integrate and weigh a diversity of input signals. Signal integration within the signalling networks occurs at different sites including the level of transcription factor activation. Accumulating evidence assigns a major and diversified role in environmental signal integration to the family of APETALA 2/ethylene response element binding protein (AP2/EREBP) transcription factors. Presently, the Plant Transcription Factor Database 3.0 assigns 147 gene loci to this family in Arabidopsis thaliana, 200 in Populus trichocarpa and 163 in Oryza sativa subsp. japonica as compared to 13 to 14 in unicellular algae ( http://plntfdb.bio.uni-potsdam.de/v3.0/ ). AP2/EREBP transcription factors have been implicated in hormone, sugar and redox signalling in context of abiotic stresses such as cold and drought. This review exemplarily addresses present-day knowledge of selected AP2/EREBP with focus on a function in stress signal integration and retrograde signalling and defines AP2/EREBP-linked gene networks from transcriptional profiling-based graphical Gaussian models. The latter approach suggests highly interlinked functions of AP2/EREBPs in retrograde and stress signalling.

The acclimation of Chlorella to high-level nitrite for potential application in biological NOx removal from industrial flue gases

Czech Academy of Sciences Publication Activity Database

Li, T.; Xu, G.; Rong, J.; Chen, H.; He, Ch.; Giordano, Mario; Wang, Q.

2016-01-01

Roč. 195, May (2016), s. 73-79 ISSN 0176-1617 Institutional support: RVO:61388971 Keywords : Acclimation * Biological NOx removal * Chlorella Subject RIV: EF - Botanics Impact factor: 3.121, year: 2016

Study Finds Association between Biological Marker and Susceptibility to the Common Cold

Science.gov (United States)

... W X Y Z Study Finds Association Between Biological Marker and Susceptibility to the Common Cold Share: © ... a cold caused by a particular rhinovirus. The biological marker identified in the study was the length ...

Elevated Temperature and CO2 Stimulate Late-Season Photosynthesis But Impair Cold Hardening in Pine[OPEN

Science.gov (United States)

2016-01-01

Rising global temperature and CO2 levels may sustain late-season net photosynthesis of evergreen conifers but could also impair the development of cold hardiness. Our study investigated how elevated temperature, and the combination of elevated temperature with elevated CO2, affected photosynthetic rates, leaf carbohydrates, freezing tolerance, and proteins involved in photosynthesis and cold hardening in Eastern white pine (Pinus strobus). We designed an experiment where control seedlings were acclimated to long photoperiod (day/night 14/10 h), warm temperature (22°C/15°C), and either ambient (400 μL L−1) or elevated (800 μmol mol−1) CO2, and then shifted seedlings to growth conditions with short photoperiod (8/16 h) and low temperature/ambient CO2 (LTAC), elevated temperature/ambient CO2 (ETAC), or elevated temperature/elevated CO2 (ETEC). Exposure to LTAC induced down-regulation of photosynthesis, development of sustained nonphotochemical quenching, accumulation of soluble carbohydrates, expression of a 16-kD dehydrin absent under long photoperiod, and increased freezing tolerance. In ETAC seedlings, photosynthesis was not down-regulated, while accumulation of soluble carbohydrates, dehydrin expression, and freezing tolerance were impaired. ETEC seedlings revealed increased photosynthesis and improved water use efficiency but impaired dehydrin expression and freezing tolerance similar to ETAC seedlings. Sixteen-kilodalton dehydrin expression strongly correlated with increases in freezing tolerance, suggesting its involvement in the development of cold hardiness in P. strobus. Our findings suggest that exposure to elevated temperature and CO2 during autumn can delay down-regulation of photosynthesis and stimulate late-season net photosynthesis in P. strobus seedlings. However, this comes at the cost of impaired freezing tolerance. Elevated temperature and CO2 also impaired freezing tolerance. However, unless the frequency and timing of extreme low

Field-acclimated Gossypium hirsutum cultivars exhibit genotypic and seasonal differences in photosystem II thermostability.

Science.gov (United States)

Snider, John L; Oosterhuis, Derrick M; Collins, Guy D; Pilon, Cristiane; Fitzsimons, Toby R

2013-03-15

Previous investigations have demonstrated that photosystem II (PSII) thermostability acclimates to prior exposure to heat and drought, but contrasting results have been reported for cotton (Gossypium hirsutum). We hypothesized that PSII thermotolerance in G. hirsutum would acclimate to environmental conditions during the growing season and that there would be differences in PSII thermotolerance between commercially-available U.S. cultivars. To this end, three cotton cultivars were grown under dryland conditions in Tifton Georgia, and two under irrigated conditions in Marianna Arkansas. At Tifton, measurements included PSII thermotolerance (T15, the temperature causing a 15% decline in maximum quantum yield), leaf temperatures, air temperatures, midday (1200 to 1400h) leaf water potentials (ΨMD), leaf-air vapor pressure deficit (VPD), actual quantum yield (ΦPSII) and electron transport rate through PSII (ETR) on three sample dates. At Marianna, T15 was measured on two sample dates. Optimal air and leaf temperatures were observed on all sample dates in Tifton, but PSII thermotolerance increased with water deficit conditions (ΨMD=-3.1MPa), and ETR was either unaffected or increased under water-stress. Additionally, T15 for PHY 499 was ∼5°C higher than for the other cultivars examined (DP 0912 and DP 1050). The Marianna site experienced more extreme high temperature conditions (20-30 days Tmax≥35°C), and showed an increase in T15 with higher average Tmax. When average T15 values for each location and sample date were plotted versus average daily Tmax, strong, positive relationships (r(2) from .954 to .714) were observed between Tmax and T15. For all locations T15 was substantially higher than actual field temperature conditions. We conclude that PSII thermostability in G. hirsutum acclimates to pre-existing environmental conditions; PSII is extremely tolerant to high temperature and water-deficit stress; and differences in PSII thermotolerance exist between

Cold urticaria. Dissociation of cold-evoked histamine release and urticara following cold challenge.

Science.gov (United States)

Keahey, T M; Greaves, M W

1980-02-01

Nine patients with acquired cold urticaria were studied to assess the effects of beta-adrenergic agents, xanthines, and corticosteroids on cold-evoked histamine release from skin in vivo. The patients, in all of whom an immediate urticarial response developed after cooling of the forearm, demonstrated release of histamine into the venous blood draining that forearm. Following treatment with aminophylline and albuterol in combination or prednisone alone, suppression of histamine release occurred in all but one patient. In some patients, this was accompanied by a subjective diminution in pruritus or buring, but there was no significant improvement in the ensuing edema or erythema. In one patient, total suppression of histamine release was achieved without any effect on whealing and erythema in response to cold challenge. Our results suggest that histamine is not central to the pathogenesis of vascular changes in acquired cold urticaria.

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

De Novo Transcriptome Sequencing and the Hypothetical Cold Response Mode of Saussurea involucrata in Extreme Cold Environments.

Science.gov (United States)

Li, Jin; Liu, Hailiang; Xia, Wenwen; Mu, Jianqiang; Feng, Yujie; Liu, Ruina; Yan, Panyao; Wang, Aiying; Lin, Zhongping; Guo, Yong; Zhu, Jianbo; Chen, Xianfeng

2017-06-07

Saussurea involucrata grows in high mountain areas covered by snow throughout the year. The temperature of this habitat can change drastically in one day. To gain a better understanding of the cold response signaling pathways and molecular metabolic reactions involved in cold stress tolerance, genome-wide transcriptional analyses were performed using RNA-Seq technologies. A total of 199,758 transcripts were assembled, producing 138,540 unigenes with 46.8 Gb clean data. Overall, 184,416 (92.32%) transcripts were successfully annotated. The 365 transcription factors identified (292 unigenes) belonged to 49 transcription factor families associated with cold stress responses. A total of 343 transcripts on the signal transduction (132 upregulated and 212 downregulated in at least any one of the conditions) were strongly affected by cold temperature, such as the CBL-interacting serine/threonine-protein kinase ( CIPKs ), receptor-like protein kinases , and protein kinases . The circadian rhythm pathway was activated by cold adaptation, which was necessary to endure the severe temperature changes within a day. There were 346 differentially expressed genes (DEGs) related to transport, of which 138 were upregulated and 22 were downregulated in at least any one of the conditions. Under cold stress conditions, transcriptional regulation, molecular transport, and signal transduction were involved in the adaptation to low temperature in S. involucrata . These findings contribute to our understanding of the adaptation of plants to harsh environments and the survival traits of S. involucrata . In addition, the present study provides insight into the molecular mechanisms of chilling and freezing tolerance.

Impacts of triclosan exposure on zebrafish early-life stage: Toxicity and acclimation mechanisms.

Science.gov (United States)

Falisse, Elodie; Voisin, Anne-Sophie; Silvestre, Frédéric

2017-08-01

Triclosan (TCS) is a broad spectrum antibacterial agent widely used in personal care products and present in most aquatic ecosystems. This study investigated the occurrence of triclosan acclimation and the biological mechanisms underlying the stress response triggered in early-life stage of zebrafish. Zebrafish eggs were first exposed to four different sublethal concentrations of TCS (2, 20, 50 and 100μg/L) for 7days following fertilization and subsequently exposed to a lethal concentration of TCS (1000μg/L). During the time-to-death exposure (TTD), mortality was continuously recorded to evaluate if increased resistance occurred. Overall, larvae exposed to 50μg/L of TCS demonstrated higher sensitivity, with delayed hatching and increased mortality during the sub-lethal exposure and significant lower mean time-to-death (TTD) value compared to the other groups. Interestingly, fish exposed to the highest concentration of TCS (100μg/L) presented a similar mean TTD value as controls and a significantly better survival in comparison with embryos exposed to 50μg/L, suggesting that acclimation process has been triggered at this concentration. Proteomic and enzymatic analyses were conducted on 7days post fertilization (dpf) larvae exposed to 50μg/L and 100μg/L of TCS giving insights into the functional changes triggered at those specific concentrations. TCS seemed to affect proteins involved in cytoskeleton, stress response, eyes and neuronal development. This was endorsed by the enzymatic results, which suggest impairment in glutathione metabolism and acute neurotoxicity. A significant 2.5-fold and 3-fold increase of AChE activity was observed following TCS exposure. Moreover, GPx activity was significantly increased whereas a significant inhibition of GR activity was observed, suggesting that de novo synthesis of reduced GSH might occur in order to maintain the ratio between reduced and oxidized GSH. Proteomic results revealed possible candidate protein involved in

Identification and expression analysis of cold and freezing stress responsive genes of Brassica oleracea.

Science.gov (United States)

Ahmed, Nasar Uddin; Jung, Hee-Jeong; Park, Jong-In; Cho, Yong-Gu; Hur, Yoonkang; Nou, Ill-Sup

2015-01-10

Cold and freezing stress is a major environmental constraint to the production of Brassica crops. Enhancement of tolerance by exploiting cold and freezing tolerance related genes offers the most efficient approach to address this problem. Cold-induced transcriptional profiling is a promising approach to the identification of potential genes related to cold and freezing stress tolerance. In this study, 99 highly expressed genes were identified from a whole genome microarray dataset of Brassica rapa. Blast search analysis of the Brassica oleracea database revealed the corresponding homologous genes. To validate their expression, pre-selected cold tolerant and susceptible cabbage lines were analyzed. Out of 99 BoCRGs, 43 were differentially expressed in response to varying degrees of cold and freezing stress in the contrasting cabbage lines. Among the differentially expressed genes, 18 were highly up-regulated in the tolerant lines, which is consistent with their microarray expression. Additionally, 12 BoCRGs were expressed differentially after cold stress treatment in two contrasting cabbage lines, and BoCRG54, 56, 59, 62, 70, 72 and 99 were predicted to be involved in cold regulatory pathways. Taken together, the cold-responsive genes identified in this study provide additional direction for elucidating the regulatory network of low temperature stress tolerance and developing cold and freezing stress resistant Brassica crops. Copyright © 2014 Elsevier B.V. All rights reserved.

BBGD: an online database for blueberry genomic data

Directory of Open Access Journals (Sweden)

Matthews Benjamin F

2007-01-01

Full Text Available Abstract Background Blueberry is a member of the Ericaceae family, which also includes closely related cranberry and more distantly related rhododendron, azalea, and mountain laurel. Blueberry is a major berry crop in the United States, and one that has great nutritional and economical value. Extreme low temperatures, however, reduce crop yield and cause major losses to US farmers. A better understanding of the genes and biochemical pathways that are up- or down-regulated during cold acclimation is needed to produce blueberry cultivars with enhanced cold hardiness. To that end, the blueberry genomics database (BBDG was developed. Along with the analysis tools and web-based query interfaces, the database serves both the broader Ericaceae research community and the blueberry research community specifically by making available ESTs and gene expression data in searchable formats and in elucidating the underlying mechanisms of cold acclimation and freeze tolerance in blueberry. Description BBGD is the world's first database for blueberry genomics. BBGD is both a sequence and gene expression database. It stores both EST and microarray data and allows scientists to correlate expression profiles with gene function. BBGD is a public online database. Presently, the main focus of the database is the identification of genes in blueberry that are significantly induced or suppressed after low temperature exposure. Conclusion By using the database, researchers have developed EST-based markers for mapping and have identified a number of "candidate" cold tolerance genes that are highly expressed in blueberry flower buds after exposure to low temperatures.

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.

Plant adaptation or acclimation to rising CO2 ? Insight from first multigenerational RNA-Seq transcriptome.

Science.gov (United States)

Watson-Lazowski, Alexander; Lin, Yunan; Miglietta, Franco; Edwards, Richard J; Chapman, Mark A; Taylor, Gail

2016-11-01

Atmospheric carbon dioxide (CO 2 ) directly determines the rate of plant photosynthesis and indirectly effects plant productivity and fitness and may therefore act as a selective pressure driving evolution, but evidence to support this contention is sparse. Using Plantago lanceolata L. seed collected from a naturally high CO 2 spring and adjacent ambient CO 2 control site, we investigated multigenerational response to future, elevated atmospheric CO 2 . Plants were grown in either ambient or elevated CO 2 (700 μmol mol -1 ), enabling for the first time, characterization of the functional and population genomics of plant acclimation and adaptation to elevated CO 2 . This revealed that spring and control plants differed significantly in phenotypic plasticity for traits underpinning fitness including above-ground biomass, leaf size, epidermal cell size and number and stomatal density and index. Gene expression responses to elevated CO 2 (acclimation) were modest [33-131 genes differentially expressed (DE)], whilst those between control and spring plants (adaptation) were considerably larger (689-853 DE genes). In contrast, population genomic analysis showed that genetic differentiation between spring and control plants was close to zero, with no fixed differences, suggesting that plants are adapted to their native CO 2 environment at the level of gene expression. An unusual phenotype of increased stomatal index in spring but not control plants in elevated CO 2 correlated with altered expression of stomatal patterning genes between spring and control plants for three loci (YODA, CDKB1;1 and SCRM2) and between ambient and elevated CO 2 for four loci (ER, YODA, MYB88 and BCA1). We propose that the two positive regulators of stomatal number (SCRM2) and CDKB1;1 when upregulated act as key controllers of stomatal adaptation to elevated CO 2 . Combined with significant transcriptome reprogramming of photosynthetic and dark respiration and enhanced growth in spring plants

Protective mechanisms and acclimation to solar ultraviolet-B radiation in Oenothera stricta

Science.gov (United States)

Robberecht, R.; Caldwell, M. M.

1981-01-01

Plant adaptations ameliorating or repairing the damaging effects of ultraviolet-B (UV-B) radiation on plant tissue were investigated. The degree of phenotype plasticity in UV protective mechanisms and acclimation in relation to the natural solar UV-B radiation flux and in an enhanced UV-B irradiance environment was also examined. Mechanisms by which plants avoid radiation, adaptations altering the path of radiation incident on the leaf, and repair processes were considered. Attenuation of UV-B by tissues, UV-B irradiation into the leaf, and the effects of UV-B on photosynthesis were investigated.

Burning Cold: Involvement of TRPA1 in Noxious Cold Sensation

OpenAIRE

Kwan, Kelvin Y.; Corey, David P.

2009-01-01

Soon after its discovery ten years ago, the ion channel TRPA1 was proposed as a sensor of noxious cold. Evidence for its activation by painfully cold temperatures (below ~15° C) has been mixed, however. Some groups found that cold elicits a nonselective conductance in cells expressing TRPA1; others found no activation, or argued that activation is an indirect effect of elevated \\(Ca^{ 2+}\\) . Sensory cells from the trigeminal and dorsal root ganglia that are activated by cold were sometimes c...

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

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

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.

Freezing avoidance by supercooling in Olea europaea cultivars: the role of apoplastic water, solute content and cell wall rigidity.

Science.gov (United States)

Arias, Nadia S; Bucci, Sandra J; Scholz, Fabian G; Goldstein, Guillermo

2015-10-01

Plants can avoid freezing damage by preventing extracellular ice formation below the equilibrium freezing temperature (supercooling). We used Olea europaea cultivars to assess which traits contribute to avoid ice nucleation at sub-zero temperatures. Seasonal leaf water relations, non-structural carbohydrates, nitrogen and tissue damage and ice nucleation temperatures in different plant parts were determined in five cultivars growing in the Patagonian cold desert. Ice seeding in roots occurred at higher temperatures than in stems and leaves. Leaves of cold acclimated cultivars supercooled down to -13 °C, substantially lower than the minimum air temperatures observed in the study site. During winter, leaf ice nucleation and leaf freezing damage (LT50 ) occurred at similar temperatures, typical of plant tissues that supercool. Higher leaf density and cell wall rigidity were observed during winter, consistent with a substantial acclimation to sub-zero temperatures. Larger supercooling capacity and lower LT50 were observed in cold-acclimated cultivars with higher osmotically active solute content, higher tissue elastic adjustments and lower apoplastic water. Irreversible leaf damage was only observed in laboratory experiments at very low temperatures, but not in the field. A comparative analysis of closely related plants avoids phylogenetic independence bias in a comparative study of adaptations to survive low temperatures. © 2015 John Wiley & Sons Ltd.

Cold-Induced Thermogenesis and Inflammation-Associated Cold-Seeking Behavior Are Represented by Different Dorsomedial Hypothalamic Sites: A Three-Dimensional Functional Topography Study in Conscious Rats.

Science.gov (United States)

Wanner, Samuel P; Almeida, M Camila; Shimansky, Yury P; Oliveira, Daniela L; Eales, Justin R; Coimbra, Cândido C; Romanovsky, Andrej A

2017-07-19

In the past, we showed that large electrolytic lesions of the dorsomedial hypothalamus (DMH) promoted hypothermia in cold-exposed restrained rats, but attenuated hypothermia in rats challenged with a high dose of bacterial lipopolysaccharide (LPS) in a thermogradient apparatus. The goal of this study was to identify the thermoeffector mechanisms and DMH representation of the two phenomena and thus to understand how the same lesion could produce two opposite effects on body temperature. We found that the permissive effect of large electrolytic DMH lesions on cold-induced hypothermia was due to suppressed thermogenesis. DMH-lesioned rats also could not develop fever autonomically: they did not increase thermogenesis in response to a low, pyrogenic dose of LPS (10 μg/kg, i.v.). In contrast, changes in thermogenesis were uninvolved in the attenuation of the hypothermic response to a high, shock-inducing dose of LPS (5000 μg/kg, i.v.); this attenuation was due to a blockade of cold-seeking behavior. To compile DMH maps for the autonomic cold defense and for the cold-seeking response to LPS, we studied rats with small thermal lesions in different parts of the DMH. Cold thermogenesis had the highest representation in the dorsal hypothalamic area. Cold seeking was represented by a site at the ventral border of the dorsomedial nucleus. Because LPS causes both fever and hypothermia, we originally thought that the DMH contained a single thermoregulatory site that worked as a fever-hypothermia switch. Instead, we have found two separate sites: one that drives thermogenesis and the other, previously unknown, that drives inflammation-associated cold seeking. SIGNIFICANCE STATEMENT Cold-seeking behavior is a life-saving response that occurs in severe systemic inflammation. We studied this behavior in rats with lesions in the dorsomedial hypothalamus (DMH) challenged with a shock-inducing dose of bacterial endotoxin. We built functional maps of the DMH and found the strongest

Cold-Hearted or Cool-Headed: Physical Coldness Promotes Utilitarian Moral Judgment

Directory of Open Access Journals (Sweden)

Hiroko eNakamura

2014-10-01

Full Text Available In the current study, we examine the effect of physical coldness on personal moral dilemma judgment. Previous studies have indicated that utilitarian moral judgment—sacrificing a few people to achieve the greater good for others—was facilitated when: (1 participants suppressed an initial emotional response and deliberately thought about the utility of outcomes; (2 participants had a high-level construal mindset and focused on abstract goals (e.g., save many; or (3 there was a decreasing emotional response to sacrificing a few. In two experiments, we exposed participants to extreme cold or typical room temperature and then asked them to make personal moral dilemma judgments. The results of Experiment 1 indicated that coldness prompted utilitarian judgment, but the effect of coldness was independent from deliberate thought or abstract high-level construal mindset. As Experiment 2 revealed, coldness facilitated utilitarian judgment via reduced empathic feelings. Therefore, physical coldness did not affect the cool-headed deliberate process or the abstract high-level construal mindset. Rather, coldness biased people toward being cold-hearted, reduced empathetic concern about a sacrificed victim, and facilitated utilitarian moral judgments.

Individuals' knowledge and practices of the cold chain.

Science.gov (United States)

Uçar, Aslı; Ozçelik, Ayşe Özfer

2013-01-01

This study aims to identify the influence of education on the practices and knowledge of consumers to protect or maintain the cold chain in the Turkish capital of Ankara. Data were gathered by using a questionnaire. Participants were 700 randomly selected volunteering adults. The majority of the participants had a university degree (69.0%) and did not know the definition of cold chain but had some knowledge about it, and differences existed between primary school and university graduates. The scores of consumers' attitudes to maintain cold chain were determined to increase in parallel with education level. The rate of people knowing refrigerator temperature, the coldest part of refrigerator, and controlling whether shops correctly store the products was highest in university graduates. Adults were observed to believe that shop assistants were responsible for maintaining a cold chain. However, the actual importance of consumers in this process reveals the importance of education for individuals.

Physiological acclimation of a desert antelope, Arabian oryx (Oryx leucoryx), to long-term food and water restriction.

Science.gov (United States)

Ostrowski, Stéphane; Williams, Joseph B; Mésochina, Pascal; Sauerwein, Helga

2006-03-01

Desert mammals often experience scarcity of drinking water and food for prolonged periods. In this study, the first long-term acclimation experiment in a non-domesticated desert-adapted ungulate, we investigated the mechanisms used by the Arabian oryx Oryx leucoryx, to adjust its physiology to progressive food and water restriction over 5 months, an experimental regimen and time course chosen to mimic what it typically experiences between spring and late summer in the desert. At the end of the acclimation period, oryx consumed less than one and half of food and water of animals in the control group and lost 8.2+/-2.6% of their initial body mass. Experimental animals reduced their mass-specific resting metabolic rate (RMR) and total evaporative water loss (TEWL) by 16.2 and 25.7%, respectively, and maintained a digestive efficiency of about 70%. We found no support for the idea that reduced RMR in oryx correlated with a decreased thyroid hormone concentration in plasma. At the end of the 5 months acclimation, oryx continued to mobilize fatty acids to fuel metabolism, and did not use protein breakdown as a major source of gluconeogenesis. Oryx in the experimental group reduced their water intake by 70% and maintained constant plasma osmolality. They adjusted their water budget by reducing mass-specific TEWL, increasing urine osmolality and reducing urine volume by 40%, and excreting feces with <50% water content. Oryx have an unusually low TEWL compared with other arid-zone ungulates; both hydrated and water-deprived individuals have TEWL values, 51.7 and 39.3%, respectively, of allometric predictions for arid-zone ungulates.

Aspects of cold intrusions over Greece during autumn

Science.gov (United States)

Mita, Constantina; Marinaki, Aggeliki; Zeini, Konstantina; Konstantara, Metaxia

2010-05-01

This study is focused on the description of atmospheric disturbances that caused intense cold intrusions over Greece during autumn for a period of 25 years (1982-2006). The study was based on data analysis from the meteorological station network of the Hellenic National Meteorological Service (HNMS) and the European Centre for Medium Range Weather Forecasts (ECMWF). Initially, the days with temperature at the isobaric surface of 850 hPa less or equal to the mean temperature for the 10-day period the day under investigation belongs to are isolated, composing a new confined data set which was further used. An event of intense cold intrusion is identified based on a subjective set of criteria, considering the temperature decrease at the level of 850 hPa and its duration. In particular, the criteria that were used to identify a cold intrusion were: temperature variation between two successive days at the isobaric level of 850 hPa being equal or greater than 50 C at least once during the event and duration of the event of at least two successive days with continuous temperature decrease. Additionally, the synoptic analysis of the atmospheric disturbances involved using weather charts from ECMWF, revealed that all cases were related to low pressure systems at the level of 500 hPa, accompanied by cold air masses. Moreover, a methodology proposed to classify the cold intrusions based on general circulation characteristics of the atmosphere, resulted in seven major categories. More than half of the events belong in two categories, originated northwest of the greater Greek area (Greece and parts of neighbouring countries), between 400 and 600 N. Further analysis indicated that the frequency of events increases from September to November and the majority of the events lasted two to three days. Additionally, the non-parametric Mann-Kendall test was used for the investigation of the statistical significance of the trends appearing in the results. The tests revealed that over

Dynamics of cold acclimation and complex phytohormone responses in Triticum monococcum lines G3116 and DV92 differing in vernalization and frost tolerance level

Czech Academy of Sciences Publication Activity Database

Vaňková, Radomíra; Kosová, K.; Dobrev, Petre; Vítámvás, P.; Trávníčková, Alena; Cvikrová, Milena; Pešek, Bedřich; Gaudinová, Alena; Přerostová, Sylva; Musilová, J.; Galiba, G.; Prášil, I.T.

2014-01-01

Roč. 101, MAY 2014 (2014), s. 12-25 ISSN 0098-8472 R&D Projects: GA ČR GA522/09/2058 Grant - others:GA ČR GPP501/11/P637 Program:GP Institutional support: RVO:61389030 Keywords : Cold stress * Dehydrin * Einkorn wheat Subject RIV: ED - Physiology Impact factor: 3.359, year: 2014

Ice recrystallization inhibition proteins (IRIPs) and freeze tolerance in the cryophilic Antarctic hair grass Deschampsia antarctica E. Desv.

Science.gov (United States)

John, Ulrik P; Polotnianka, Renatam M; Sivakumaran, Kailayapillai A; Chew, Orinda; Mackin, Leanne; Kuiper, Micheal J; Talbot, Jonathan P; Nugent, Gregory D; Mautord, Julie; Schrauf, Gustavo E; Spangenberg, German C

2009-04-01

Antarctic hair grass (Deschampsia antarctica E. Desv.), the only grass indigenous to Antarctica, has well-developed freezing tolerance, strongly induced by cold acclimation. Here, we show that in response to low temperatures, D. antarctica expresses potent recrystallization inhibition (RI) activity that, inhibits the growth of small ice crystals into potentially damaging large ones, is proteinaceous and localized to the apoplasm. A gene family from D. antarctica encoding putative homologs of an ice recrystallization inhibition protein (IRIP) has been isolated and characterized. IRIPs are apoplastically targeted proteins with two potential ice-binding motifs: 1-9 leucine-rich repeats (LRRs) and c. 16 'IRIP' repeats. IRIP genes appear to be confined to the grass subfamily Pooideae and their products, exhibit sequence similarity to phytosulphokine receptors and are predicted to adopt conformations with two ice-binding surfaces. D. antarctica IRIP (DaIRIP) transcript levels are greatly enhanced in leaf tissue following cold acclimation. Transgenic Arabidopsis thaliana expressing a DaIRIP has novel RI activity, and purified DaIRIP, when added back to extracts of leaves from non-acclimated D. antarctica, can reconstitute the activity found in acclimated plants. We propose that IRIP-mediated RI activity may contribute to the cryotolerance of D. antarctica, and thus to its unique ability to have colonized Antarctica.

Regulation and acclimation of leaf gas exchange in a piñon-juniper woodland exposed to three different precipitation regimes.

Science.gov (United States)

Limousin, Jean-Marc; Bickford, Christopher P; Dickman, Lee T; Pangle, Robert E; Hudson, Patrick J; Boutz, Amanda L; Gehres, Nathan; Osuna, Jessica L; Pockman, William T; McDowell, Nate G

2013-10-01

Leaf gas-exchange regulation plays a central role in the ability of trees to survive drought, but forecasting the future response of gas exchange to prolonged drought is hampered by our lack of knowledge regarding potential acclimation. To investigate whether leaf gas-exchange rates and sensitivity to drought acclimate to precipitation regimes, we measured the seasonal variations of leaf gas exchange in a mature piñon-juniper Pinus edulis-Juniperus monosperma woodland after 3 years of precipitation manipulation. We compared trees receiving ambient precipitation with those in an irrigated treatment (+30% of ambient precipitation) and a partial rainfall exclusion (-45%). Treatments significantly affected leaf water potential, stomatal conductance and photosynthesis for both isohydric piñon and anisohydric juniper. Leaf gas exchange acclimated to the precipitation regimes in both species. Maximum gas-exchange rates under well-watered conditions, leaf-specific hydraulic conductance and leaf water potential at zero photosynthetic assimilation all decreased with decreasing precipitation. Despite their distinct drought resistance and stomatal regulation strategies, both species experienced hydraulic limitation on leaf gas exchange when precipitation decreased, leading to an intraspecific trade-off between maximum photosynthetic assimilation and resistance of photosynthesis to drought. This response will be most detrimental to the carbon balance of piñon under predicted increases in aridity in the southwestern USA. © 2013 John Wiley & Sons Ltd.

Hyperprolinemic larvae of the drosophilid fly, Chymomyza costata, survive cryopreservation in liquid nitrogen.

Science.gov (United States)

Kostál, Vladimír; Zahradnícková, Helena; Šimek, Petr

2011-08-09

The larva of the drosophilid fly, Chymomyza costata, is probably the most complex metazoan organism that can survive submergence in liquid nitrogen (-196 °C) in a fully hydrated state. We examined the associations between the physiological and biochemical parameters of differently acclimated larvae and their freeze tolerance. Entering diapause is an essential and sufficient prerequisite for attaining high levels of survival in liquid nitrogen (23% survival to adult stage), although cold acclimation further improves this capacity (62% survival). Profiling of 61 different metabolites identified proline as a prominent compound whose concentration increased from 20 to 147 mM during diapause transition and subsequent cold acclimation. This study provides direct evidence for the essential role of proline in high freeze tolerance. We increased the levels of proline in the larval tissues by feeding larvae proline-augmented diets and found that this simple treatment dramatically improved their freeze tolerance. Cell and tissue survival following exposure to liquid nitrogen was evident in proline-fed nondiapause larvae, and survival to adult stage increased from 0% to 36% in proline-fed diapause-destined larvae. A significant statistical correlation was found between the whole-body concentration of proline, either natural or artificial, and survival to the adult stage in liquid nitrogen for diapause larvae. Differential scanning calorimetry analysis suggested that high proline levels, in combination with a relatively low content of osmotically active water and freeze dehydration, increased the propensity of the remaining unfrozen water to undergo a glass-like transition (vitrification) and thus facilitated the prevention of cryoinjury.

THE COLD AND DARK PROCESS AT THE SAVANNAH RIVER SITE

International Nuclear Information System (INIS)

Gilmour, J; William Austin, W; Cathy Sizemore, C

2007-01-01

The deactivation and decommissioning (D and D) of a facility exposes D and D workers to numerous hazards. One of the more serious hazards is coming into contact to hazardous energy sources (e.g. electrical, pressurized steam). At the Savannah River Site (SRS) a formal process for identifying and eliminating sources of hazardous energy was developed and is called ''Cold and Dark''. Several ''near miss'' events involving cutting of energized conductors during D and D work in buildings thought to be isolated identified the need to have a formal process to identify and isolate these potentially hazardous systems. This process was developed using lessons learned from D and D activities at the Rocky Flats Environmental Technology Site (Rocky Flats) in Colorado. The Cold and Dark process defines an isolation boundary (usually a building perimeter) and then systematically identifies all of the penetrations through this boundary. All penetrations that involve hazardous energy sources are then physically air-gapped. The final product is a documented declaration of isolation performed by a team involving operations, engineering, and project management. Once the Cold and Dark declaration is made for a building work can proceed without the usual controls used in an operational facility (e.g. lockout/tagout, arc flash PPE). It is important to note that the Cold and Dark process does not remove all hazards from a facility. Work planning and controls still need to address hazards that can be present from such things as chemicals, radiological contamination, residual liquids, etc., as well as standard industrial hazards

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

and enhanced cell membrane peroxidation, as exemplified by increased O2-• production rate and reduction in activities of antioxiditave enzymes. However, under post-anthesis heat stress, plants with pre-anthesis hightemperature acclimation (HH)showedmuchhigher photosynthetic rates than those without pre...... all up-regulated under HH, whereas a gene encoding a major chlorophyll a/b-binding protein (Cab) was up-regulated by post-anthesis heat stress at 10 DAA, but was down-regulated at 13 DAA. The changes in the expression levels of the HH plants were more pronounced than those for the CH. Collectively......, 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...

Grooved cold moderator tests

International Nuclear Information System (INIS)

Inoue, K.; Kiyanagi, Y.; Iwasa, H.; Watanabe, N.; Ikeda, S.; Carpenter, J.M.; Ishikawa, Y.

1983-01-01

We performed some grooved cold moderator experiments for methane at 20 K by using the Hokkaido University linac to obtain information to be used in the planning of the KENS-I' project. Cold neutron gains, spatial distribution of emitted beams and time distribution of the neutrons in the grooved cold moderator were measured. Furthermore, we assessed the effects of the grooved cold moderator on the performances of the spectrometers presently installed at the KENS-I cold source. We concluded that the grooved cold moderator benefited appreciably the performances of the spectrometers

Trans-life cycle acclimation to experimental ocean acidification affects gastric pH homeostasis and larval recruitment in the sea star Asterias rubens.

Science.gov (United States)

Hu, Marian Y; Lein, Etienne; Bleich, Markus; Melzner, Frank; Stumpp, Meike

2018-04-16

Experimental simulation of near-future ocean acidification (OA) has been demonstrated to affect growth and development of echinoderm larval stages through energy allocation towards ion and pH compensatory processes. To date, it remains largely unknown how major pH regulatory systems and their energetics are affected by trans-generational exposure to near-future acidification levels. Here we used the common sea star Asterias rubens in a reciprocal transplant experiment comprising different combinations of OA scenarios, in order to study trans-generational plasticity using morphological and physiological endpoints. Acclimation of adults to pH T 7.2 (pCO 2 3500μatm) led to reductions in feeding rates, gonad weight, and fecundity. No effects were evident at moderate acidification levels (pH T 7.4; pCO 2 2000μatm). Parental pre-acclimation to pH T 7.2 for 85 days reduced developmental rates even when larvae were raised under moderate and high pH conditions, whereas pre-acclimation to pH T 7.4 did not alter offspring performance. Microelectrode measurements and pharmacological inhibitor studies carried out on larval stages demonstrated that maintenance of alkaline gastric pH represents a substantial energy sink under acidified conditions that may contribute up to 30% to the total energy budget. Parental pre-acclimation to acidification levels that are beyond the pH that is encountered by this population in its natural habitat (e.g. pH T 7.2) negatively affected larval size and development, potentially through reduced energy transfer. Maintenance of alkaline gastric pH and reductions in maternal energy reserves probably constitute the main factors for a reduced juvenile recruitment of this marine keystone species under simulated OA. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.

Species-specific physiological response by the cold-water corals Lophelia pertusa and Madrepora oculata to variations within their natural temperature range

Science.gov (United States)

Naumann, Malik S.; Orejas, Covadonga; Ferrier-Pagès, Christine

2014-01-01

The scleractinian cold-water corals (CWC) Lophelia pertusa and Madrepora oculata represent two major deep-sea reef-forming species that act as key ecosystem engineers over a wide temperature range, extending from the northern Atlantic (ca. 5-9 °C) to the Mediterranean Sea (ca. 11-13 °C). Recent research suggests that environmental parameters, such as food supply, settling substrate availability or aragonite saturation state may represent important precursors controlling habitat suitability for CWC. However, the effect of one principal environmental factor, temperature, on CWC key physiological processes is still unknown. In order to evaluate this effect on calcification, respiration, and dissolved organic carbon (DOC) net flux, colonies of Mediterranean L. pertusa and M. oculata were acclimated in aquaria to three temperatures (12, 9 and 6 °C), by consecutive decrements of 1 month duration. L. pertusa and M. oculata maintained at Mediterranean control conditions (i.e. 12 °C) displayed constant rates, on average respiring 4.8 and 4.0 μmol O2 cm-2 coral surface area d-1, calcifying 22.3 and 12.3 μmol CaCO3 g-1 skeletal dry weight d-1 and net releasing 2.6 and 3.1 μmol DOC cm-2 coral surface area d-1, respectively. Respiration of L. pertusa was not affected by lowered temperatures, while M. oculata respiration declined significantly (by 48%) when temperature decreased to 9 °C and 6 °C relative to controls. L. pertusa calcification at 9 °C was similar to controls, but decreased significantly (by 58%) at 6 °C. For M. oculata, calcification declined by 41% at 9 °C and by 69% at 6 °C. DOC net flux was similar throughout the experiment for both CWC. These findings reveal species-specific physiological responses by CWC within their natural temperature range. L. pertusa shows thermal acclimation in respiration and calcification, while these mechanisms appear largely absent in M. oculata. Conclusively, species-specific thermal acclimation may significantly affect

Excretion of 137 Cs and bio energetic processes in Carp Cyprinus Carpio L. in the time of his acclimation to different concentrations of potassium in the water

International Nuclear Information System (INIS)

Romanenko, V.D.; Solomatina, V.D.; Fomovskij, M.A.; Nasvit, O.I.

1995-01-01

The result of the investigation on the peculiarities of 137 Cs release acclimatized to different potassium concentration in water are reported. The differences in characteristics of ion exchange and bioenergetic processes between fishes acclimated to different potassium concentrations were mainly eliminated to the 28-th day of acclimation period. The dynamics of radiocesium release is characterized by slow and just components. No differences in 137 Cs release rate were observed in experiments with different water potassium concentrations

An RNA-Seq transcriptome analysis of orthophosphate-deficient white lupin reveals novel insights into phosphorus acclimation in plants.

Science.gov (United States)

O'Rourke, Jamie A; Yang, S Samuel; Miller, Susan S; Bucciarelli, Bruna; Liu, Junqi; Rydeen, Ariel; Bozsoki, Zoltan; Uhde-Stone, Claudia; Tu, Zheng Jin; Allan, Deborah; Gronwald, John W; Vance, Carroll P

2013-02-01

Phosphorus, in its orthophosphate form (P(i)), is one of the most limiting macronutrients in soils for plant growth and development. However, the whole-genome molecular mechanisms contributing to plant acclimation to P(i) deficiency remain largely unknown. White lupin (Lupinus albus) has evolved unique adaptations for growth in P(i)-deficient soils, including the development of cluster roots to increase root surface area. In this study, we utilized RNA-Seq technology to assess global gene expression in white lupin cluster roots, normal roots, and leaves in response to P(i) supply. We de novo assembled 277,224,180 Illumina reads from 12 complementary DNA libraries to build what is to our knowledge the first white lupin gene index (LAGI 1.0). This index contains 125,821 unique sequences with an average length of 1,155 bp. Of these sequences, 50,734 were transcriptionally active (reads per kilobase per million reads ≥ 3), representing approximately 7.8% of the white lupin genome, using the predicted genome size of Lupinus angustifolius as a reference. We identified a total of 2,128 sequences differentially expressed in response to P(i) deficiency with a 2-fold or greater change and P ≤ 0.05. Twelve sequences were consistently differentially expressed due to P(i) deficiency stress in three species, Arabidopsis (Arabidopsis thaliana), potato (Solanum tuberosum), and white lupin, making them ideal candidates to monitor the P(i) status of plants. Additionally, classic physiological experiments were coupled with RNA-Seq data to examine the role of cytokinin and gibberellic acid in P(i) deficiency-induced cluster root development. This global gene expression analysis provides new insights into the biochemical and molecular mechanisms involved in the acclimation to P(i) deficiency.