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Sample records for acid accumulation limits

  1. Investigation of fatty acid accumulation in the engineered Saccharomyces cerevisiae under nitrogen limited culture condition.

    Tang, Xiaoling; Chen, Wei Ning

    2014-06-01

    In this study, the Saccharomyces cerevisiae wild type strain and engineered strain with an overexpressed heterologous ATP-citrate lyase (acl) were cultured in medium with different carbon and nitrogen concentrations, and their fatty acid production levels were investigated. The results showed that when the S. cerevisiae engineered strain was cultivated under nitrogen limited culture condition, the yield of mono-unsaturated fatty acids showed higher than that under non-nitrogen limited condition; with the carbon concentration increased, the accumulation become more apparent, whereas in the wild type strain, no such correlation was found. Besides, the citrate level in the S. cerevisiae under nitrogen limited condition was found to be much higher than that under non-nitrogen limited condition, which indicated a relationship between the diminution of nitrogen and accumulation of citrate in the S. cerevisiae. The accumulated citrate could be further cleaved by acl to provide substrate for fatty acid synthesis. PMID:24755317

  2. Supply of fatty acid is one limiting factor in the accumulation of triacylglycerol in developing embryos

    Bao, X.; Ohlrogge, J.

    1999-08-01

    The metabolic factors that determine oil yield in seeds are still not well understood. To begin to examine the limits on triacylglycerol (TAG) production, developing Cuphea lanceolata, Ulmus carpinifolia, and Ulmus parvifolia embryos were incubated with factors whose availability might limit oil accumulation. The addition of glycerol or sucrose did not significantly influence the rate of TAG synthesis. However, the rate of {sup 14}C-TAG synthesis upon addition of 2.1 mM {sup 14}C-decanoic acid (10:0) was approximately four times higher than the in vivo rate of TAG accumulation in C. lanceolata and two times higher than the in vivo rate in U. carpinifolia and U. parvifolia. In C. lanceolata embryos, the highest rate of {sup 14}C-TAG synthesis (14.3 nmol h{sup {minus}1} embryo {sup {minus}1}) was achieved with the addition of 3.6 mM decanoic acid. {sup 14}C-Decanoic acid was incorporated equally well in all three acyl positions of TAG. The results suggest that C. lancelata, U. Carpinifolia, and U. parvifolia embryos have sufficient acyltransferase activities and glycerol-3-phosphate levels to support rates of TAG synthesis in excess of those found in vivo. Consequently, the amount of TAG synthesized in these oilseeds may be in part determined by the amount of fatty acid produced in plastids.

  3. Combined nitrogen limitation and cadmium stress stimulate total carbohydrates, lipids, protein and amino acid accumulation in Chlorella vulgaris (Trebouxiophyceae)

    Chia, Mathias Ahii, E-mail: chia28us@yahoo.com [Department of Botany, Federal University of São Carlos, Rodovia Washington Luis km 235, São Carlos, SP Cep 13565905 (Brazil); Lombardi, Ana Teresa [Department of Botany, Federal University of São Carlos, Rodovia Washington Luis km 235, São Carlos, SP Cep 13565905 (Brazil); Graça Gama Melão, Maria da [Department of Hydrobiology, Federal University of São Carlos, Rodovia Washington Luis km 235, São Carlos, SP Cep 13565905 (Brazil); Parrish, Christopher C. [Department of Ocean Sciences, Memorial University of Newfoundland, St. John’s, Newfoundland A1C 5S7 (Canada)

    2015-03-15

    Highlights: • Chlorella vulgaris was exposed to Cd under varying N concentrations. • Growth rate and cell density decreased with increasing Cd stress and N limitation. • Dry weight, chlorophyll a, total lipid, carbohydrate and protein were accumulated. • Amino acids like proline and glutamine were accumulated under N and Cd stress. • Changes in amino acid composition are sensitive biomarkers for Cd and N stress. - Abstract: Metals have interactive effects on the uptake and metabolism of nutrients in microalgae. However, the effect of trace metal toxicity on amino acid composition of Chlorella vulgaris as a function of varying nitrogen concentrations is not known. In this research, C. vulgaris was used to investigate the influence of cadmium (10{sup −7} and 2.0 × 10{sup −8} mol L{sup −1} Cd) under varying nitrogen (2.9 × 10{sup −6}, 1.1 × 10{sup −5} and 1.1 × 10{sup −3} mol L{sup −1} N) concentrations on its growth rate, biomass and biochemical composition. Total carbohydrates, total proteins, total lipids, as well as individual amino acid proportions were determined. The combination of Cd stress and N limitation significantly inhibited growth rate and cell density of C. vulgaris. However, increasing N limitation and Cd stress stimulated higher dry weight and chlorophyll a production per cell. Furthermore, biomolecules like total proteins, carbohydrates and lipids increased with increasing N limitation and Cd stress. Ketogenic and glucogenic amino acids were accumulated under the stress conditions investigated in the present study. Amino acids involved in metal chelation like proline, histidine and glutamine were significantly increased after exposure to combined Cd stress and N limitation. We conclude that N limitation and Cd stress affects the physiology of C. vulgaris by not only decreasing its growth but also stimulating biomolecule production.

  4. Combined nitrogen limitation and cadmium stress stimulate total carbohydrates, lipids, protein and amino acid accumulation in Chlorella vulgaris (Trebouxiophyceae)

    Highlights: • Chlorella vulgaris was exposed to Cd under varying N concentrations. • Growth rate and cell density decreased with increasing Cd stress and N limitation. • Dry weight, chlorophyll a, total lipid, carbohydrate and protein were accumulated. • Amino acids like proline and glutamine were accumulated under N and Cd stress. • Changes in amino acid composition are sensitive biomarkers for Cd and N stress. - Abstract: Metals have interactive effects on the uptake and metabolism of nutrients in microalgae. However, the effect of trace metal toxicity on amino acid composition of Chlorella vulgaris as a function of varying nitrogen concentrations is not known. In this research, C. vulgaris was used to investigate the influence of cadmium (10−7 and 2.0 × 10−8 mol L−1 Cd) under varying nitrogen (2.9 × 10−6, 1.1 × 10−5 and 1.1 × 10−3 mol L−1 N) concentrations on its growth rate, biomass and biochemical composition. Total carbohydrates, total proteins, total lipids, as well as individual amino acid proportions were determined. The combination of Cd stress and N limitation significantly inhibited growth rate and cell density of C. vulgaris. However, increasing N limitation and Cd stress stimulated higher dry weight and chlorophyll a production per cell. Furthermore, biomolecules like total proteins, carbohydrates and lipids increased with increasing N limitation and Cd stress. Ketogenic and glucogenic amino acids were accumulated under the stress conditions investigated in the present study. Amino acids involved in metal chelation like proline, histidine and glutamine were significantly increased after exposure to combined Cd stress and N limitation. We conclude that N limitation and Cd stress affects the physiology of C. vulgaris by not only decreasing its growth but also stimulating biomolecule production

  5. Bromine accumulation in acidic black colluvial soils

    Cortizas, Antonio Martínez; Vázquez, Cruz Ferro; Kaal, Joeri; Biester, Harald; Casais, Manuela Costa; Rodríguez, Teresa Taboada; Lado, Luis Rodríguez

    2016-02-01

    Recent investigations showed that bromine is incorporated to soil organic matter (SOM), its content increasing with humification. But few research was done on its long-term accumulation and the role played by pedogenetic processes, as those involved in organic matter stabilization. We investigated bromine content and distribution in four deep, acidic, organic-rich, Holocene soils from an oceanic area of Western Europe. Bromine concentrations (93-778 μg g-1) in the silt + clay (area, and total estimated retention was low (6-16%). The degree of SOM bromination, expressed as the Br/C molar ratio, varied between 0.03 and 1.20 mmol Br/mol C. The ratio was highly correlated (n = 23, r2 0.88, p pool of metal-clay-stabilized organic matter.

  6. Using lead-acid accumulators in hybrid electric vehicle regime

    Hejdiš, Roman

    2010-01-01

    The master´s thesis discuss characteristics of hybrid electric vehicles and lead-acid accumulators applied in car industry. It compares classic and alternative drive in cars, descibes classification of hybrid drives and its characteristics. Further work disscus lead-acid accumulators which focuses on VRLA accumulators applied in hybrid electric cars. Practical part contains a construction description of negative electrode and experiment, which studied influence of various amount addition of c...

  7. Surface-atmosphere decoupling limits accumulation at Summit, Greenland.

    Berkelhammer, Max; Noone, David C; Steen-Larsen, Hans Christian; Bailey, Adriana; Cox, Christopher J; O'Neill, Michael S; Schneider, David; Steffen, Konrad; White, James W C

    2016-04-01

    Despite rapid melting in the coastal regions of the Greenland Ice Sheet, a significant area (~40%) of the ice sheet rarely experiences surface melting. In these regions, the controls on annual accumulation are poorly constrained owing to surface conditions (for example, surface clouds, blowing snow, and surface inversions), which render moisture flux estimates from myriad approaches (that is, eddy covariance, remote sensing, and direct observations) highly uncertain. Accumulation is partially determined by the temperature dependence of saturation vapor pressure, which influences the maximum humidity of air parcels reaching the ice sheet interior. However, independent proxies for surface temperature and accumulation from ice cores show that the response of accumulation to temperature is variable and not generally consistent with a purely thermodynamic control. Using three years of stable water vapor isotope profiles from a high altitude site on the Greenland Ice Sheet, we show that as the boundary layer becomes increasingly stable, a decoupling between the ice sheet and atmosphere occurs. The limited interaction between the ice sheet surface and free tropospheric air reduces the capacity for surface condensation to achieve the rate set by the humidity of the air parcels reaching interior Greenland. The isolation of the surface also acts to recycle sublimated moisture by recondensing it onto fog particles, which returns the moisture back to the surface through gravitational settling. The observations highlight a unique mechanism by which ice sheet mass is conserved, which has implications for understanding both past and future changes in accumulation rate and the isotopic signal in ice cores from Greenland. PMID:27386509

  8. Targeting acid sphingomyelinase reduces cardiac ceramide accumulation in the post-ischemic heart.

    Klevstig, Martina; Ståhlman, Marcus; Lundqvist, Annika; Scharin Täng, Margareta; Fogelstrand, Per; Adiels, Martin; Andersson, Linda; Kolesnick, Richard; Jeppsson, Anders; Borén, Jan; Levin, Malin C

    2016-04-01

    Ceramide accumulation is known to accompany acute myocardial ischemia, but its role in the pathogenesis of ischemic heart disease is unclear. In this study, we aimed to determine how ceramides accumulate in the ischemic heart and to determine if cardiac function following ischemia can be improved by reducing ceramide accumulation. To investigate the association between ceramide accumulation and heart function, we analyzed myocardial left ventricle biopsies from subjects with chronic ischemia and found that ceramide levels were higher in biopsies from subjects with reduced heart function. Ceramides are produced by either de novo synthesis or hydrolysis of sphingomyelin catalyzed by acid and/or neutral sphingomyelinase. We used cultured HL-1 cardiomyocytes to investigate these pathways and showed that acid sphingomyelinase activity rather than neutral sphingomyelinase activity or de novo sphingolipid synthesis was important for hypoxia-induced ceramide accumulation. We also used mice with a partial deficiency in acid sphingomyelinase (Smpd1(+/-) mice) to investigate if limiting ceramide accumulation under ischemic conditions would have a beneficial effect on heart function and survival. Although we showed that cardiac ceramide accumulation was reduced in Smpd1(+/-) mice 24h after an induced myocardial infarction, this reduction was not accompanied by an improvement in heart function or survival. Our findings show that accumulation of cardiac ceramides in the post-ischemic heart is mediated by acid sphingomyelinase. However, targeting ceramide accumulation in the ischemic heart may not be a beneficial treatment strategy. PMID:26930027

  9. Acid Rain Limits Global Warming

    Will Knight; 张林玲

    2004-01-01

    @@ Acid rain restricts global warming by reducing methane① emissions from natural wetland areas, suggests a global climate study. Acid rain is the result of industrial pollution,which causes rainwater to carry small quantities of acidic compoumds② such as sulphuric and nitric acid③. Contaminated rainwater can upset rivers and lakes, killing fish and other organisms and also damage plants, trees and buildings.

  10. Cholic acid is accumulated spontaneously, driven by membrane Delta pH, in many lactobacilli

    Kurdi, P; van Veen, HW; Tanaka, H; Mierau, [No Value; Konings, WN; Tannock, GW; Tomita, F; Yokota, A

    2000-01-01

    Many lactobacilli from various origins were found to apparently lack cholic acid extrusion activity. Cholic acid was accumulated spontaneously, driven by the transmembrane proton gradient. Accumulation is a newly identified kind of interaction between intestinal microbes and unconjugated bile acids

  11. Susceptibility of riparian wetland plants to perfluorooctanoic acid (PFOA) accumulation.

    Mudumbi, J B N; Ntwampe, S K O; Muganza, M; Okonkwo, J O

    2014-01-01

    As plants have been shown to accumulate organic compounds from contaminated sediments, there is a potential for long-lasting ecological impact as a result of contaminant accumulation in riparian areas of wetlands, particularly the accumulation of non-biodegradable contaminants such as perfluorooctanoic acid (PFOA). In this study, commonly found riparian wetland plants including reeds, i.e., Xanthium strumarium, Phragmites australis, Schoenoplectus corymbosus, Ruppia maritime; Populus canescens, Polygonum salicifolium, Cyperus congestus; Persicaria amphibian, Ficus carica, Artemisia schmidtiana, Eichhornia crassipes, were studied to determine their susceptibility to PFOA accumulation from PFOA contaminated riparian sediment with a known PFOA concentration, using liquid chromatography/tandem mass spectrometry (LC/MS/MS). The bioconcentration factor (BCF) indicated that the plants affinity to PFOA accumulation was; E. crassipes, > P. sali-cifolium, > C. congestus, > P. x canescens, > P. amphibian, > F. carica, > A. schmidtiana, > X. strumarium,> P. australis, > R. maritime, > S. corymbosus. The concentration of PFOA in the plants and/or reeds was in the range 11.7 to 38 ng/g, with a BCF range of 0.05 to 0.37. The highest BCF was observed in sediment for which its core water had a high salinity, total organic carbon and a pH which was near neutral. As the studied plants had a higher affinity for PFOA, the resultant effect is that riparian plants such as E. crassipes, X. strumarium, and P. salicifolium, typified by a fibrous rooting system, which grow closer to the water edge, exacerbate the accumulation of PFOA in riparian wetlands. PMID:24933893

  12. Limited accumulation of copper in heavy metal adapted mosses.

    Antreich, Sebastian; Sassmann, Stefan; Lang, Ingeborg

    2016-04-01

    Copper is an essential micronutrient but has toxic effects at high concentrations. Bryophytes are remarkably tolerant to elevated levels of copper but we wondered if this tolerance might be species dependent. Therefore, in three moss species, Physcomitrella patens, Mielichhoferia elongata and Pohlia drummondii, the accumulation of copper was compared with semiquantitative SEM-EDX analyses after six weeks of cultivation on copper containing media. We investigated the role of the copper-linked anion and applied copper as CuCl2, CuSO4 and CuEDTA, respectively. Line scans along the growth axis of moss gametophores allowed for a detailed analysis of copper detection from the base towards the tip. Mosses originating from metal-containing habitats (i.e. M. elongata and P. drummondii) revealed a lower accumulation of copper when compared to the non-adapted P. patens. CuEDTA had a shielding effect in all three species and copper levels differed greatly from CuCl2 or CuSO4. The detection of reactive oxygen species (ROS), H2O2 and O2(-), was further used to indicate stress levels in the gametophore stems. ROS staining was increased along the whole stem and the tip in the non-adapted species P. patens whereas the tolerant species M. elongata and P. drummondii generally showed less staining located mainly at the base of the stem. We discuss the relation between metal accumulation and ROS production using indicator dyes in the three moss species. As moss gametophores are very delicate structures, ROS staining provide an excellent alternative to spectrophotometric analyses to estimate stress levels. PMID:26878481

  13. Global southern limit of flowering plants and moss peat accumulation

    Peter Convey

    2011-10-01

    Full Text Available The ecosystems of the western Antarctic Peninsula, experiencing amongst the most rapid trends of regional climate warming worldwide, are important “early warning” indicators for responses expected in more complex systems elsewhere. Central among responses attributed to this regional warming are widely reported population and range expansions of the two native Antarctic flowering plants, Deschampsia antarctica and Colobanthus quitensis. However, confirmation of the predictions of range expansion requires baseline knowledge of species distributions. We report a significant southwards and westwards extension of the known natural distributions of both plant species in this region, along with several range extensions in an unusual moss community, based on a new survey work in a previously unexamined and un-named low altitude peninsula at 69°22.0′S 71°50.7′W in Lazarev Bay, north-west Alexander Island, southern Antarctic Peninsula. These plant species therefore have a significantly larger natural range in the Antarctic than previously thought. This site provides a potentially important monitoring location near the southern boundary of the region currently demonstrated to be under the influence of rapidly changing climate trends. Combined radiocarbon and lead isotope radiometric dating suggests that this location was most likely deglaciated sufficiently to allow peat to start accumulating towards the end of the 19th century, which we tentatively link to a phase of post-1870 climate amelioration. We conclude that the establishment of vegetation in this location is unlikely to be linked to the rapid regional warming trends recorded along the Antarctic Peninsula since the mid-20th century.

  14. Caffeoylquinic Acids Generated In Vitro in a High-Anthocyanin-Accumulating Sweet potato Cell Line

    Izabela Konczak; Shigenori Okuno; Makoto Yoshimoto; Osamu Yamakawa

    2004-01-01

    Accumulation of phenolic compounds has been monitored in a suspension culture of anthocyanin-accumulating sweet potato cell line grown under the conditions of modified Murashige and Skoog high-anthocyanin production medium (APM) over a period of 24 days. Tissue samples extracted with 15% acetic acid were analysed using HPLC at a detection wavelength of 326 nm. Among others, the following derivatives of caffeoylquinic acids were detected: 4,5-dicaffeoylquinic acid, 3,5-dicaffeoylquinic acid, 3...

  15. Phosphate limitation promotes unsaturated fatty acids and arachidonic acid biosynthesis by microalgae Porphyridium purpureum.

    Su, Gaomin; Jiao, Kailin; Li, Zheng; Guo, Xiaoyi; Chang, Jingyu; Ndikubwimana, Theoneste; Sun, Yong; Zeng, Xianhai; Lu, Yinghua; Lin, Lu

    2016-07-01

    Polyunsaturated fatty acids (PUFAs) are highly appreciated on their nutritive value for human health and aquaculture. P. purpureum, one of the red microalgae acknowledged as a promising accumulator of ARA, was chosen as the target algae in the present research. Effects of sodium bicarbonate (0.04-1.2 g/L), temperature (25, 30 and 33 °C) and phosphate (0.00-0.14 g/L) on biomass yield, total fatty acids (TFA) and arachidonic acid (ARA) accumulation were investigated systemically. NaHCO3 dose of 0.8 g/L and moderate temperature of 30 °C were preferred. In addition, TFA and ARA production were significantly enhanced by an appropriate concentration of phosphate, and the highest TFA yield of 666.38 mg/L and ARA yield of 159.74 mg/L were obtained at a phosphate concentration of 0.035 g/L. Interestingly, with phosphate concentration continuing to fall, UFA/TFA and ARA/EPA ratios were increased accordingly, suggesting that phosphate limitation promoted unsaturated fatty acids and arachidonic acid biosynthesis. Low concentration of phosphate may be favored to increase the enzymatic activities of ∆6-desaturase, which played a key role in catalyzing the conversion of C16:0 to C18:2, and thus the selectivity of UFA increased. Meanwhile, the increase of ARA selectivity could be attributed to ω6 pathway promotion and ∆17-desaturase activity inhibition with phosphate limitation. Phosphate limitation strategy enhanced unsaturated fatty acids and ARA biosynthesis in P. purpureum, and can be applied in commercial scale manufacturing and commercialization of ARA. PMID:27004948

  16. Avoiding propionic acid accumulation in the anaerobic process for biohydrogen production

    The accumulation of propionic acid in the anaerobic process will result in low efficiency of the methanogenic phase due to the low acetogenic rate of propionic acid, and hence low wastewater treatment efficiency. The reasons for propionic acid accumulation in the acidogenic phase and the relationship between the accumulation and biohydrogen generation were studied and a strategy for avoiding propionic acid accumulation in the anaerobic process for biohydrogen generation is also introduced. The experimental results indicate that changing pH and oxidation-reduction potential (ORP) can result in the variation of fermentation type, and maintaining lower ORP and avoiding pH of 5.5 will reduce the accumulation of propionic acid in the anaerobic process. Higher biohydrogen generation rate is not always accompanied with the accumulation of propionic acid. In the acidogenic reactor of two-phase separated anaerobic process, ethanol type fermentation, in which pH at 4.5 below, can produce much more biohydrogen but without accumulation of propionic acid. Thus, ethanol-type fermentation is a better selection when using an acidogenic reactor of a two-phase separated anaerobic process to efficiently produce biohydrogen with simultaneous organic wastewater pre-treatment

  17. Oil and fatty acid accumulation during coriander (Coriandrum sativum L. fruit ripening under organic cultivation

    Quang-Hung Nguyen

    2015-08-01

    Full Text Available To evaluate the accumulation of oil and fatty acids in coriander during fruit ripening, a field experiment was conducted under organic cultivation conditions in Auch (near Toulouse, southwestern France during the 2009 cropping season. The percentage and composition of the fatty acids of coriander were determined by gas chromatography. Our results showed that rapid oil accumulation started in early stages (two days after flowering, DAF. Twelve fatty acids were identified. Saturated and polyunsaturated acids were the dominant fatty acids at earlier stages (2–12 DAF, but decreased after this date. After this stage, petroselinic acid increased to its highest amount at 18 DAF. In contrast, palmitic acid followed the opposite trend. Saturated and polyunsaturated fatty acids decreased markedly and monounsaturated fatty acids increased during fruit maturation. It appears that the fruit of coriander may be harvested before full maturity.

  18. Influence of Climatic Conditions on Accumulation of α-acids in Hop Clones

    Siniša Srečec

    2008-09-01

    Full Text Available The influence of climatic conditions on accumulation of α-acids was determined during the six years (2001 – 2006 of stationary experiment in hop cultivar Aurora. The research results show that increasing sum of effective temperatures during the technological maturity stay in negative correlation with accumulation of α-acids in hop cones (r = - 0.39*, whereas total rainfalls stays in positive one (r = 0.46* At the same time sum of hours of sun shining stay in not significant negative correlation with the accumulation of α-acids (r = - 0.38. The results of factorial analysis show significant positive multiple correlation between sum of effective temperatures and total rainfalls with α-acids accumulation (multiple r = 0.6232** and at the same time show a significant positive multiple correlation between total rainfalls and sunshine hours with α-acids accumulation (multiple r = 0.5492*. However, there was a very strong negative influence of reference crop evapotranspiration during the phenological phase of hop cones formation on yield of hop cones and of α-acids (rs = - 0.75* and – 0.88*, respectively. The total rainfalls during the hop vegetation in interval of [212.1; 391.8] mm and also the sum of effective temperature in interval of [1601.74; 2000] ºC caused the α-acids accumulation in hop cones of cultivar Aurora in interval of [7.41; 12.35] % in dry matter. It is important to point out that the level of provided tillage, plant protection measures and fertilization was the same in all six experimental years, which excluded their effects on accumulation of α-acids. These results could possibly contribute in creating a model of predication of α-acids accumulation and beginning of hop harvest.

  19. Ammonia activates pacC and patulin accumulation in an acidic environment during apple colonization by Penicillium expansum.

    Barad, Shiri; Espeso, Eduardo A; Sherman, Amir; Prusky, Dov

    2016-06-01

    Penicillium expansum, the causal agent of blue mould rot, causes severe post-harvest fruit maceration simultaneously with the secretion of d-gluconic acid (GLA) and the mycotoxin patulin in colonized tissue. The factor(s) inducing patulin biosynthesis during colonization of the host acidic environment is unclear. During the colonization of apple fruit in vivo and growth in culture, P. expansum secretes pH-modulating GLA and ammonia. Although patulin and its possible opportunistic precursor GLA accumulate together during fungal development, ammonia is detected on the colonized tissue's leading edge and after extended culture, close to patulin accumulation. Here, we demonstrate ammonia-induced transcript activation of the global pH modulator PacC and patulin accumulation in the presence of GLA by: (i) direct exogenous treatment of P. expansum growing on solid medium; (ii) direct exogenous treatment on colonized apple tissue; (iii) growth under self-ammonia production conditions with limited carbon; and (iv) analysis of the transcriptional response to ammonia of the patulin biosynthesis cluster. Ammonia induced patulin accumulation concurrently with the transcript activation of pacC and patulin biosynthesis cluster genes, indicating the regulatory effect of ammonia on pacC transcript expression under acidic conditions. Electrophoretic mobility shift assays using P. expansum PacC and antibodies to the different cleaved proteins showed that PacC is not protected against proteolytic signalling at pH 4.5 relative to pH 7.0, but NH4 addition did not further enhance its proteolytic cleavage. Ammonia enhanced the activation of palF transcript in the Pal pathway under acidic conditions. Ammonia accumulation in the host environment by the pathogen under acidic pH may be a regulatory cue for pacC activation, towards the accumulation of secondary metabolites, such as patulin. PMID:26420024

  20. Limited Resources, Limited Opportunities, and the Accumulation of Disadvantage: Evidence from the Global Survey of Physicists

    Ivie, Rachel

    2012-03-01

    Using the results of the Global Survey of Physicists, which we conducted in collaboration with the International Union of Pure and Applied Physics Working Group on Women, we document the effect of limited resources and opportunities on women physicists' careers. We find that women respondents are less likely than men to report access to a variety of resources and opportunities that would be helpful in advancing a scientific career. These include access to funding, travel money, lab and office space, equipment, clerical support, and availability of employees or students to help with research. When asked about specific opportunities, women report fewer invited talks and overseas research opportunities. Women who responded are less likely to have been journal editors, acted as bosses or managers, advised graduate students, served on thesis or dissertation committees, and served on committees for grant agencies. We also show the disproportionate effects of children on women physicists' careers. Women who responded are more likely than men to have changed their work situations upon becoming parents. Mothers are more likely than men and women without children to report that their careers have progressed more slowly than colleagues who finished their degrees at the same time. Furthermore, women are more likely than men to report that their careers affected the decisions they made about marriage and children. The results of this survey draw attention to the need to focus on factors other than representation when discussing the situation of women in physics. 15,000 physicists in 130 countries answered this survey, and across all these countries, women have fewer resources and opportunities and are more affected by cultural expectations concerning child care. Cultural expectations about home and family are difficult to change. However, for women to have successful outcomes and advance in physics, they must have equal access to resources and opportunities.

  1. Hyperosmosis and its combination with nutrient-limitation are novel environmental stressors for induction of triacylglycerol accumulation in cells of Chlorella kessleri.

    Hirai, Kazuho; Hayashi, Taihei; Hasegawa, Yuri; Sato, Atsushi; Tsuzuki, Mikio; Sato, Norihiro

    2016-01-01

    Triacylglycerols of oleaginous algae are promising for production of food oils and biodiesel fuel. Air-drying of cells induces triacylglycerol accumulation in a freshwater green alga, Chlorella kessleri, therefore, it seems that dehydration, i.e., intracellular hyperosmosis, and/or nutrient-limitation are key stressors. We explored this possibility in liquid-culturing C. kessleri cells. Strong hyperosmosis with 0.9 M sorbitol or 0.45 M NaCl for two days caused cells to increase the triacylglycerol content in total lipids from 1.5 to 48.5 and 75.3 mol%, respectively, on a fatty acid basis, whereas nutrient-limitation caused its accumulation to 41.4 mol%. Even weak hyperosmosis with 0.3 M sorbitol or 0.15 M NaCl, when nutrient-limitation was simultaneously imposed, induced triacylglycerol accumulation to 61.9 and 65.7 mol%, respectively. Furthermore, culturing in three-fold diluted seawater, the chemical composition of which resembled that of the medium for the combinatory stress, enabled the cells to accumulate triacylglycerol up to 24.7 weight% of dry cells in only three days. Consequently, it was found that hyperosmosis is a novel stressor for triacylglycerol accumulation, and that weak hyperosmosis, together with nutrient-limitation, exerts a strong stimulating effect on triacylglycerol accumulation. A similar combinatory stress would contribute to the triacylglycerol accumulation in air-dried C. kessleri cells. PMID:27184595

  2. Concomitant extracellular accumulation of alpha-keto acids and higher alcohols by Zygosaccharomyces rouxii.

    Van Der Sluis, Catrinus; Rahardjo, Yovita S P; Smit, Bart A; Kroon, Pieter J; Hartmans, Sybe; Ter Schure, Eelko G; Tramper, Johannes; Wijffels, Renéh

    2002-01-01

    Alpha-keto acids are key intermediates in the formation of higher alcohols, important flavor components in soy sauce, and produced by the salt-tolerant yeast Zygosaccharomyces rouxii. Unlike most of the higher alcohols, the alpha-keto acids are usually not extracellularly accumulated by Z. rouxii when it is cultivated with ammonium as the sole nitrogen source. To facilitate extracellular accumulation of the alpha-keto acids from aspartate-derived amino acid metabolism, the amino acids valine, leucine, threonine and methionine were exogenously supplied during batch and A-star cultivations of (routants of) Z. rouxii. It was shown that all alpha-keto acids from the aspartate-derived amino acid metabolism, except alpha-ketobutyrate, could be extracellularly accumulated. In addition, it appeared from the concomitant extracellular accumulation of alpha-keto acids and higher alcohols that in Z. rouxii, valine, leucine and methionine were converted via Ehrlich pathways similar to those in Saccharomyces cerevisiae. Unlike these amino acids, threonine was converted via both the Ehrlich and amino acid biosynthetic pathways in Z. rouxii. PMID:16233175

  3. AtNOA1 modulates nitric oxide accumulation and stomatal closure induced by salicylic acid in Arabidopsis

    Sun, Li Rong; Hao, Fu Shun; Lu, Bao Shi; Ma, Li Ya

    2010-01-01

    Phytohormone salicylic acid (SA) has been documented to induce nitric oxide (NO) generation and stomatal closure in plants. However, the cellular components mediating these processes are limited. Here, we report that NO synthesis in guard cells and stomatal closure are markedly induced by SA in Arabidopsis wild type plants, whereas these effects caused by SA are suppressed significantly in noa1 T-DNA mutant plants. These results suggest that AtNOA1 regulates SA-triggered NO accumulation and s...

  4. Mechanism and controlling strategy of the production and accumulation of propionic acid for anaerobic wastewater treatment

    任南琪; 李建政; 赵丹; 陈晓蕾

    2002-01-01

    The production and accumulation of propionic acid affect significantly anaerobic wastewater treatment system, but the reasons are not approached until now. Based on the results of continuous-flow tests and the analysis of biochemistry and ecology, two mechanisms of producing propionic acid have been put forward. It is demonstrated that the reasons of propionic acid production and accumulation are not caused by higher hydrogen partial pressure. The combination of specific pH value and ORP is the ecological factor affecting propionic acid production, and the equilibrium regulation of NADH/NAD+ ratio in cells is the physiological factor. Meanwhile, it is put forward that using the two-phase anaerobic treatment process and the ethanol type fermentation in anaerobic reactor to avoid propionic acid accumulation are efficient methods.

  5. Improved cadmium uptake and accumulation in the hyperaccumulator Sedum alfredii: the impact of citric acid and tartaric acid* #

    Lu, Ling-li; Tian, Sheng-ke; Yang, Xiao-e; Peng, Hong-yun; Li, Ting-qiang

    2013-01-01

    The elucidation of a natural strategy for metal hyperaccumulation enables the rational design of technologies for the clean-up of metal-contaminated soils. Organic acid has been suggested to be involved in toxic metallic element tolerance, translocation, and accumulation in plants. The impact of exogenous organic acids on cadmium (Cd) uptake and translocation in the zinc (Zn)/Cd co-hyperaccumulator Sedum alfredii was investigated in the present study. By the addition of organic acids, short-t...

  6. The relationship between lumenal and limiting membranes in swollen late endocytic compartments formed after wortmannin treatment or sucrose accumulation.

    Bright, N A; Lindsay, M R; Stewart, A; Luzio, J P

    2001-09-01

    Immunofluorescence and electron microscopy were used to evaluate the formation of swollen endosomes in NRK cells after treatment with wortmannin or sucrose and to study the relationship between lumenal and limiting membrane. Both treatments resulted in the formation of two populations of swollen late endocytic vacuoles, positive for lysosomal glycoproteins or cation-independent mannose 6-phosphate receptors, but those induced by wortmannin were characterised by time-dependent accumulation of lumenal vesicles, whereas those induced by sucrose uptake did not accumulate lumenal vesicles. In both cases, the distribution of the late endosomal marker, lysobisphosphatidic acid, remained unchanged and was present within the lumen of the swollen vacuoles. Consumption of plasma membrane and peripheral early endosomes, and the appearance of transferrin receptors in swollen late endosomes, indicated that continued membrane influx from early endocytic compartments, together with inhibition of membrane traffic out of the swollen compartments, is sufficient to account for the observed phenotype of cells treated with wortmannin. The accumulation of organelles with the characteristic morphology of endocytic carrier vesicles in cells that have taken up sucrose offers an explanation for the paucity of lumenal vesicles in swollen sucrosomes. Our data suggest that in fibroblast cells the swollen endosome phenotype induced by wortmannin is a consequence of endocytic membrane influx, coupled with the failure to recycle membrane to other cellular destinations, and not the inhibition of multivesicular body biogenesis. PMID:11555417

  7. Detoxification and Accumulation of Cadmium and Arsenic in Plants : : Implications for Phytoremediation and Limiting Accumulation in Foods

    Jobe, Timothy O.

    2013-01-01

    Many of the metals and metalloids commonly used by our modern society are extremely toxic and can pose a significant health risk if consumed. However, unlike animals, some plants are often extremely tolerant to the toxic effects of these metals and can accumulate large amounts in various tissues. Because some plants can bioaccumulate toxic metals, a number of bioremediation strategies using plants have been proposed. However, accumulation of toxic metals in agronomic crops is not desirable. I...

  8. Intracellular boron accumulation in CHO-K1 cells using amino acid transport control

    BPA used in BNCT has a similar structure to some essential amino acids and is transported into tumor cells by amino acid transport systems. Previous study groups have tried various techniques of loading BPA to increase intracellular boron concentration. CHO-K1 cells demonstrate system L (LAT1) activity and are suitable for specifying the transport system of a neutral amino acid. In this study, we examined the intracellular accumulation of boron in CHO-K1 cells by amino acid transport control, which involves co-loading with L-type amino acid esters. Intracellular boron accumulation in CHO-K1 cells showed the greatest increased upon co-loading 1.0 mM BPA, with 1.0 mM L-Tyr-O-Et and incubating for 60 min. This increase is caused by activation of a system L amino acid exchanger between BPA and L-Tyr. The amino acid esters are metabolized to amino acids by intracellular hydrolytic enzymes that increase the concentrations of intracellular amino acids and stimulate exchange transportation. We expect that this amino acid transport control will be useful for enhancing intracellular boron accumulation. - Highlights: • We examined optimal L-p-boronophenylalanine (BPA) loading in CHO-K1 cells. • Optimal BPA loading parameters were 1.0 mM and incubation for 60 min. • Intracellular boron accumulation increased upon co-loading BPA with L-Tyr-O-Et. • Optimal L-Tyr-O-Et loading parameters were 1.0 mM and incubation for 60 min. • Co-loading BPA with L-Tyr-O-Et can increase intracellular boron accumulation

  9. Rhodobacter sphaeroides mutants which accumulate 5-aminolevulinic acid under aerobic and dark conditions.

    Nishikawa, S; Watanabe, K; Tanaka, T; Miyachi, N; Hotta, Y; Murooka, Y

    1999-01-01

    The photosynthetic bacterium Rhodobacter sphaeroides accumulates 5-aminolevulinic acid (ALA), which is a precursor in tetrapyrrole biosynthesis, under light illumination and upon addition of levulinic acid as an inhibitor of ALA dehydratase. To generate an industrial strain which produces ALA in the absence of light, we sequentially mutated R. sphaeroides CR-286 using N-methyl-N'-nitro-N-nitrosoguanidine (NTG). The mutant strains were screened by cultivating in the absence of light and assayed for ALA by the Ehrlich reaction in a 96-well microtiter plate. The mutant strain CR-386, derived from R. sphaeroides CR-286, was selected as a mutant that exhibited significant ALA accumulation. While CR-286 required light illumination for ALA production, CR-386 was able to accumulate 1.5 mM ALA in the presence of 50 mM glucose, 60 mM glycine, 15 mM levulinic acid and 1.0% (w/v) yeast extract under conditions of agitation in the absence of light. The mutant strain CR-450, derived from strain CR-386, was selected further as a mutant that exhibited significant ALA accumulation but no accumulation of aminoacetone, analogue of ALA. CR-450 accumulated 3.8 mM ALA under the same conditions. In the presence of 50 mM glucose, 60 mM glycine, 5 mM levulinic acid and 1.0% (w/v) yeast extract, the mutant strain CR-520, derived from strain CR-450, and strain CR-606, derived from strain CR-520, accumulated 8.1 mM and 11.2 mM ALA, respectively. In batch fermentation, the strain CR-606 accumulated 20 mM ALA over 18 h after the addition of glycine, levulinic acid, glucose and yeast extract. PMID:16232557

  10. Effect of acetic acid on lipid accumulation by glucose-fed activated sludge cultures

    Mondala, Andro; Hernandez, Rafael; French, Todd; McFarland, Linda; Sparks, Darrell; Holmes, William; Haque, Monica

    2012-01-01

    The effect of acetic acid, a lignocellulose hydrolysis by-product, on lipid accumulation by activated sludge cultures grown on glucose was investigated. This was done to assess the possible application of lignocellulose as low-cost and renewable fermentation substrates for biofuel feedstock production. Results: Biomass yield was reduced by around 54% at a 2 g L -1 acetic acid dosage but was increased by around 18% at 10 g L -1 acetic acid dosage relative to the control run. The final gravimetric lipid contents at 2 and 10 g L -1 acetic acid levels were 12.5 + 0.7% and 8.8 + 3.2% w/w, respectively, which were lower than the control (17.8 + 2.8% w/w). However, biodiesel yields from activated sludge grown with acetic acid (5.6 + 0.6% w/w for 2 g L -1 acetic acid and 4.2 + 3.0% w/w for 10 g L -1 acetic acid) were higher than in raw activated sludge (1-2% w/w). The fatty acid profiles of the accumulated lipids were similar with conventional plant oil biodiesel feedstocks. Conclusions: Acetic acid enhanced biomass production by activated sludge at high levels but reduced lipid production. Further studies are needed to enhance acetic acid utilization by activated sludge microorganisms for lipid biosynthesis.

  11. Influence of earthworm mucus and amino acids on tomato seedling growth and cadmium accumulation

    The effects on the growth of tomato seedlings and cadmium accumulation of earthworm mucus and a solution of amino acids matching those in earthworm mucus was studied through a hydroponic experiment. The experiment included four treatments: 5 mg Cd L-1 (CC), 5 mg Cd L-1 + 100 mL L-1 earthworm mucus (CE), 5 mg Cd L-1 + 100 mL L-1 amino acids solution (CA) and the control (CK). Results showed that, compared with CC treatment, either earthworm mucus or amino acids significantly increased tomato seedling growth and Cd accumulation but the increase was much higher in the CE treatment compared with the CA treatment. This may be due to earthworm mucus and amino acids significantly increasing the chlorophyll content, antioxidative enzyme activities, and essential microelement uptake and transport in the tomato seedlings. The much greater increase in the effect of earthworm mucus compared with amino acid treatments may be due to IAA-like substances in earthworm mucus. - Earthworm mucus increased tomato seedlings growth and Cd accumulation through increasing chlorophyll content, antioxidative enzyme activities, and essential microelement accumulation.

  12. Influence of earthworm mucus and amino acids on tomato seedling growth and cadmium accumulation

    Zhang Shujie [College of Resources and Environmental Sciences, Nanjing Agricultural University, Nanjing 210095 (China); Hu Feng, E-mail: fenghu@njau.edu.c [College of Resources and Environmental Sciences, Nanjing Agricultural University, Nanjing 210095 (China); Li Huixin; Li Xiuqiang [College of Resources and Environmental Sciences, Nanjing Agricultural University, Nanjing 210095 (China)

    2009-10-15

    The effects on the growth of tomato seedlings and cadmium accumulation of earthworm mucus and a solution of amino acids matching those in earthworm mucus was studied through a hydroponic experiment. The experiment included four treatments: 5 mg Cd L{sup -1} (CC), 5 mg Cd L{sup -1} + 100 mL L{sup -1} earthworm mucus (CE), 5 mg Cd L{sup -1} + 100 mL L{sup -1} amino acids solution (CA) and the control (CK). Results showed that, compared with CC treatment, either earthworm mucus or amino acids significantly increased tomato seedling growth and Cd accumulation but the increase was much higher in the CE treatment compared with the CA treatment. This may be due to earthworm mucus and amino acids significantly increasing the chlorophyll content, antioxidative enzyme activities, and essential microelement uptake and transport in the tomato seedlings. The much greater increase in the effect of earthworm mucus compared with amino acid treatments may be due to IAA-like substances in earthworm mucus. - Earthworm mucus increased tomato seedlings growth and Cd accumulation through increasing chlorophyll content, antioxidative enzyme activities, and essential microelement accumulation.

  13. Exogenous malic and acetic acids reduce cadmium phytotoxicity and enhance cadmium accumulation in roots of sunflower plants.

    Hawrylak-Nowak, Barbara; Dresler, Sławomir; Matraszek, Renata

    2015-09-01

    There is increasing evidence showing that low molecular weight organic acids (LMWOA) are involved in heavy metal resistance mechanisms in plants. The aim of this study was to investigate the effects of exogenous malic (MA) or acetic (AA) acids on the toxicity and accumulation of cadmium (Cd) in sunflower (Helianthus annuus L.). For this purpose, plants were grown in hydroponics under controlled conditions. Single Cd stress (5 μM Cd for 14 days) induced strong phytotoxic effects, as indicated by a decrease in all growth parameters, concentration of photosynthetic pigments, and root activity, as well as a high level of hydrogen peroxide (H2O2) accumulation. Exogenous MA or AA (250 or 500 μM) applied to the Cd-containing medium enhanced the accumulation of Cd by the roots and limited Cd translocation to the shoots. Moreover, the MA or AA applied more or less reduced Cd phytotoxicity by increasing the growth parameters, photosynthetic pigment concentrations, decreasing accumulation of H2O2, and improving the root activity. Of the studied organic acids, MA was much more efficient in mitigation of Cd toxicity than AA, probably by its antioxidant effects, which were stronger than those of AA. Plant response to Cd involved decreased production of endogenous LMWOA, probably as a consequence of severe Cd toxicity. The addition of MA or AA to the medium increased endogenous accumulation of LMWOA, especially in the roots, which could be beneficial for plant metabolism. These results imply that especially MA may be involved in the processes of Cd uptake, translocation, and tolerance in plants. PMID:26115548

  14. Systems biology and metabolic modelling unveils limitations to polyhydroxybutyrate accumulation in sugarcane leaves; lessons for C4 engineering.

    McQualter, Richard B; Bellasio, Chandra; Gebbie, Leigh K; Petrasovits, Lars A; Palfreyman, Robin W; Hodson, Mark P; Plan, Manuel R; Blackman, Deborah M; Brumbley, Stevens M; Nielsen, Lars K

    2016-02-01

    In planta production of the bioplastic polyhydroxybutyrate (PHB) is one important way in which plant biotechnology can address environmental problems and emerging issues related to peak oil. However, high biomass C4 plants such as maize, switch grass and sugarcane develop adverse phenotypes including stunting, chlorosis and reduced biomass as PHB levels in leaves increase. In this study, we explore limitations to PHB accumulation in sugarcane chloroplasts using a systems biology approach, coupled with a metabolic model of C4 photosynthesis. Decreased assimilation was evident in high PHB-producing sugarcane plants, which also showed a dramatic decrease in sucrose and starch content of leaves. A subtle decrease in the C/N ratio was found which was not associated with a decrease in total protein content. An increase in amino acids used for nitrogen recapture was also observed. Based on the accumulation of substrates of ATP-dependent reactions, we hypothesized ATP starvation in bundle sheath chloroplasts. This was supported by mRNA differential expression patterns. The disruption in ATP supply in bundle sheath cells appears to be linked to the physical presence of the PHB polymer which may disrupt photosynthesis by scattering photosynthetically active radiation and/or physically disrupting thylakoid membranes. PMID:26015295

  15. Expression of fatty acid synthesis genes and fatty acid accumulation in haematococcus pluvialis under different stressors

    Lei Anping

    2012-03-01

    Full Text Available Abstract Background Biofuel has been the focus of intensive global research over the past few years. The development of 4th generation biofuel production (algae-to-biofuels based on metabolic engineering of algae is still in its infancy, one of the main barriers is our lacking of understanding of microalgal growth, metabolism and biofuel production. Although fatty acid (FA biosynthesis pathway genes have been all cloned and biosynthesis pathway was built up in some higher plants, the molecular mechanism for its regulation in microalgae is far away from elucidation. Results We cloned main key genes for FA biosynthesis in Haematococcus pluvialis, a green microalga as a potential biodiesel feedstock, and investigated the correlations between their expression alternation and FA composition and content detected by GC-MS under different stress treatments, such as nitrogen depletion, salinity, high or low temperature. Our results showed that high temperature, high salinity, and nitrogen depletion treatments played significant roles in promoting microalgal FA synthesis, while FA qualities were not changed much. Correlation analysis showed that acyl carrier protein (ACP, 3-ketoacyl-ACP-synthase (KAS, and acyl-ACP thioesterase (FATA gene expression had significant correlations with monounsaturated FA (MUFA synthesis and polyunsaturated FA (PUFA synthesis. Conclusions We proposed that ACP, KAS, and FATA in H. pluvialis may play an important role in FA synthesis and may be rate limiting genes, which probably could be modified for the further study of metabolic engineering to improve microalgal biofuel quality and production.

  16. Transcriptional and antioxidative responses to endogenous polyunsaturated fatty acid accumulation in yeast.

    Andrisic, Luka; Collinson, Emma J; Tehlivets, Oksana; Perak, Eleonora; Zarkovic, Tomislav; Dawes, Ian W; Zarkovic, Neven; Cipak Gasparovic, Ana

    2015-01-01

    Pathophysiology of polyunsaturated fatty acids (PUFAs) is associated with aberrant lipid and oxygen metabolism. In particular, under oxidative stress, PUFAs are prone to autocatalytic degradation via peroxidation, leading to formation of reactive aldehydes with numerous potentially harmful effects. However, the pathological and compensatory mechanisms induced by lipid peroxidation are very complex and not sufficiently understood. In our study, we have used yeast capable of endogenous PUFA synthesis in order to understand the effects triggered by PUFA accumulation on cellular physiology of a eukaryotic organism. The mechanisms induced by PUFA accumulation in S. cerevisiae expressing Hevea brasiliensis Δ12-fatty acid desaturase include down-regulation of components of electron transport chain in mitochondria as well as up-regulation of pentose-phosphate pathway and fatty acid β-oxidation at the transcriptional level. Interestingly, while no changes were observed at the transcriptional level, activities of two important enzymatic antioxidants, catalase and glutathione-S-transferase, were altered in response to PUFA accumulation. Increased intracellular glutathione levels further suggest an endogenous oxidative stress and activation of antioxidative defense mechanisms under conditions of PUFA accumulation. Finally, our data suggest that PUFA in cell membrane causes metabolic changes which in turn lead to adaptation to endogenous oxidative stress. PMID:25280400

  17. Gama-aminobutyric acid accumulation in Elsholtzia splendens in response to copper toxicity

    YANG Xiao-e; PENG Hong-yun; TIAN Sheng-ke

    2005-01-01

    A solution with different Cu supply levels was cultured to investigate gama-aminobutyric acid (GABA) accumulation in Elsholtzia splendens, a native Chinese Cu-tolerant and accumulating plant species. Increasing Cu from 0.25 to 500 ?mol/L significantly enhanced levels of GABA and histidine (His), but considerably decreased levels of aspartate (Asp) and glutamate (Glu) in the leaves. The leaf Asp level negatively correlated with leaf Cu level, while leaf GABA level positively correlated with leaf Cu level. The leaf Glu level negatively correlated with leaf GABA level in Elsholtzia splendens. The depletion of leaf Glu may be related to the enhanced synthesis ofleafGABA under Cu stress.

  18. Accumulation of aluminium and iron by bryophytes in streams affected by acid-mine drainage

    Engleman, C.J.; McDiffett, W.F. [Bucknell University, Lewisburg, PA (United States). Dept. of Biology

    1996-12-31

    This paper examines the accumulation of two heavy metals (Al and Fe) by bryophytes in a northern Pennsylvania stream system affected by acid-mine drainage. Four sites within one watershed were selected on the basis of their pH and dissolved metal concentrations. Significant differences among sites were found with regard to bioaccumulation of Al an Fe. A negative relationship between pH and Fe concentrations in bryophyte tissues was found, with the highest accumulation of Fe observed at the most acidic site (pH 3.5), whereas accumulation of Al was highest at a site with an intermediate pH of 5.2. Bryophytes transplanted from a circum-neutral site to acidic sites showed highly significant increases in Fe and Al concentrations in tissues after 6 weeks, and transplants from more acidic sites to a circum-neutral site generally showed highly significant declines in Fe and Al concentration in tissues after the incubation period.

  19. [Relationships between cadmium accumulation and organic acids in leaves of Solanum nigrum L. as a cadmium-hyperaccumulator].

    Sun, Rui-lian; Zhou, Qi-xing; Wang, Xin

    2006-04-01

    The influence of different cadmium concentrations on the organic acid level in leaves of the Cd hyperaccumulator, Solanum nigrum L., in particular, the relationship of organic acids with Cd accumulation in S. nigrum was investigated based on the pot-culture experiment. The results showed that the Cd concentration in S. nigrum leaves exceeded 100 microg x g(-1), the threshold value used to define Cd-hyperaccumulators, and the bioaccumulation coefficient of cadmium in shoots of S. nigrum was higher than 1 when Cd concentration in soil was 25 microg x g(-1). The level of organic acids in leaves of S. nigrum had significant differences between the seedling stage and the mature stage. At the seedling stage, the sequence of organic acids in leaves of S. nigrum was acetic acid> tartaric acid> malic acid> citric acid. On the contrary, the accumulation of organic acids in S. nigrum at the mature stage was approximately in the following sequence malic acid> tartaric acid, acetic acid> citric acid. The significant positive correlation between Cd accumulation in leaves of S. nigrum and the concentration of tartaric acid in leaves of S. nigrum was observed at the seedling stage, whereas there was a significant positive correlation between Cd accumulation in leaves of S. nigrum and both acetic and citric acid concentrations at the mature stage. These results indicated that tartaric, acetic and citric acids in leaves of S. nigrum might act as the indication of Cd hyperaccumulation. PMID:16768003

  20. Identity of the Growth-Limiting Nutrient Strongly Affects Storage Carbohydrate Accumulation in Anaerobic Chemostat Cultures of Saccharomyces cerevisiae

    Hazelwood, L.A.; Walsh, M.C.; Luttik, M.A.H.; Daran-Lapujade, P.; Pronk, J.T.; Daran, J.M.

    2009-01-01

    OA Fund TU Delft Accumulation of glycogen and trehalose in nutrient-limited cultures of Saccharomyces cerevisiae is negatively correlated with the specific growth rate. Additionally, glucose-excess conditions (i.e., growth limitation by nutrients other than glucose) are often implicated in high-lev

  1. Accumulation of the Antibiotic Phenazine-1-Carboxylic Acid in the Rhizosphere of Dryland Cereals

    Mavrodi, Dmitri V; Mavrodi, Olga V; Parejko, James A.; Bonsall, Robert F.; Kwak, Youn-Sig; Paulitz, Timothy C.; Thomashow, Linda S.; Weller, David M

    2012-01-01

    Natural antibiotics are thought to function in the defense, fitness, competitiveness, biocontrol activity, communication, and gene regulation of microorganisms. However, the scale and quantitative aspects of antibiotic production in natural settings are poorly understood. We addressed these fundamental questions by assessing the geographic distribution of indigenous phenazine-producing (Phz+) Pseudomonas spp. and the accumulation of the broad-spectrum antibiotic phenazine-1-carboxylic acid (P...

  2. Prolonged acid rain facilitates soil organic carbon accumulation in a mature forest in Southern China.

    Wu, Jianping; Liang, Guohua; Hui, Dafeng; Deng, Qi; Xiong, Xin; Qiu, Qingyan; Liu, Juxiu; Chu, Guowei; Zhou, Guoyi; Zhang, Deqiang

    2016-02-15

    With the continuing increase in anthropogenic activities, acid rain remains a serious environmental threat, especially in the fast developing areas such as southern China. To detect how prolonged deposition of acid rain would influence soil organic carbon accumulation in mature subtropical forests, we conducted a field experiment with simulated acid rain (SAR) treatments in a monsoon evergreen broadleaf forest at Dinghushan National Nature Reserve in southern China. Four levels of SAR treatments were set by irrigating plants with water of different pH values: CK (the control, local lake water, pH ≈ 4.5), T1 (water pH=4.0), T2 (water pH=3.5), and T3 (water pH=3.0). Results showed reduced pH measurements in the topsoil exposed to simulated acid rains due to soil acidification. Soil respiration, soil microbial biomass and litter decomposition rates were significantly decreased by the SAR treatments. As a result, T3 treatment significantly increased the total organic carbon by 24.5% in the topsoil compared to the control. Furthermore, surface soil became more stable as more recalcitrant organic matter was generated under the SAR treatments. Our results suggest that prolonged acid rain exposure may have the potential to facilitate soil organic carbon accumulation in the subtropical forest in southern China. PMID:26657252

  3. Effects of Aeration Treatment on γ-Aminobutyric Acid Accumulation in Germinated Tartary Buckwheat (Fagopyrum tataricum

    Yuanxin Guo

    2016-01-01

    Full Text Available To explore the optimum condition of γ-aminobutyric acid (GABA accumulation in germinated tartary buckwheat, effects of some factors including aeration treatment, physiological indexes, air flow rate, culture temperature, and pH value of cultivating solution under hypoxia on GABA in germinated tartary buckwheat were investigated. The results showed that the dark cultures with distilled water at 30°C, 2 days, and aeration stress with 1.0 L/min air flow rate at 30°C were optimal for GABA accumulation. Under these conditions, the predicted content of GABA was up to 371.98 μg/g DW. The analysis of correlation indicated that there was a significant correlation (P<0.01 between GABA accumulation and physiological indexes. Box-Behnken experimental analysis revealed that optimal conditions with aeration treatment for GABA accumulation in germinated tartary buckwheat were air flow rate of 1.04 L/min, culture temperature of 31.25°C, and a pH value of 4.21. Under these conditions, the GABA content was predicted as high as 386.20 μg/g DW, which was close to the measured value (379.00±9.30 μg/g DW. The variance analysis and validation test suggested that this established regression model could predict GABA accumulation in tartary buckwheat during germination.

  4. Competing mechanisms for perfluoroalkyl acid accumulation in plants revealed using an Arabidopsis model system.

    Müller, Claudia E; LeFevre, Gregory H; Timofte, Anca E; Hussain, Fatima A; Sattely, Elizabeth S; Luthy, Richard G

    2016-05-01

    Perfluoroalkyl acids (PFAAs) bioaccumulate in plants, presenting a human exposure route if present in irrigation water. Curiously, accumulation of PFAAs in plant tissues is greatest for both the short-chain and long-chain PFAAs, generating a U-shaped relationship with chain length. In the present study, the authors decouple competing mechanisms of PFAA accumulation using a hydroponic model plant system (Arabidopsis thaliana) exposed to a suite of 10 PFAAs to determine uptake, depuration, and translocation kinetics. Rapid saturation of root concentrations occurred for all PFAAs except perfluorobutanoate, the least-sorptive (shortest-chain) PFAA. Shoot concentrations increased continuously, indicating that PFAAs are efficiently transported and accumulate in shoots. Tissue concentrations of PFAAs during depuration rapidly declined in roots but remained constant in shoots, demonstrating irreversibility of the translocation process. Root and shoot concentration factors followed the U-shaped trend with perfluoroalkyl chain length; however, when normalized to dead-tissue sorption, this relationship linearized. The authors therefore introduce a novel term, the "sorption normalized concentration factor," to describe PFAA accumulation in plants; because of their hydrophobicity, sorption is the determining factor for long-chain PFAAs, whereas the shortest-chain PFAAs are most effectively transported in the plant. The present study provides a mechanistic explanation for previously unexplained PFAA accumulation trends in plants and suggests that shorter-chained PFAAs may bioaccumulate more readily in edible portions. Environ Toxicol Chem 2016;35:1138-1147. © 2015 SETAC. PMID:26383989

  5. Modelling metal accumulation using humic acid as a surrogate for plant roots.

    Le, T T Yen; Swartjes, Frank; Römkens, Paul; Groenenberg, Jan E; Wang, Peng; Lofts, Stephen; Hendriks, A Jan

    2015-04-01

    Metal accumulation in roots was modelled with WHAM VII using humic acid (HA) as a surrogate for root surface. Metal accumulation was simulated as a function of computed metal binding to HA, with a correction term (E(HA)) to account for the differences in binding site density between HA and root surface. The approach was able to model metal accumulation in roots to within one order of magnitude for 95% of the data points. Total concentrations of Mn in roots of Vigna unguiculata, total concentrations of Ni, Zn, Cu and Cd in roots of Pisum sativum, as well as internalized concentrations of Cd, Ni, Pb and Zn in roots of Lolium perenne, were significantly correlated to the computed metal binding to HA. The method was less successful at modelling metal accumulation at low concentrations and in soil experiments. Measured concentrations of Cu internalized in L. perenne roots were not related to Cu binding to HA modelled and deviated from the predictions by over one order of magnitude. The results indicate that metal uptake by roots may under certain conditions be influenced by conditional physiological processes that cannot simulated by geochemical equilibrium. Processes occurring in chronic exposure of plants grown in soil to metals at low concentrations complicate the relationship between computed metal binding to HA and measured metal accumulation in roots. PMID:25482978

  6. Multidrug Efflux Transporters Limit Accumulation of Inorganic, but Not Organic, Mercury in Sea Urchin Embryos

    BOŠNJAK, IVANA; Uhlinger, Kevin R.; Heim, Wesley; Smital, Tvrtko; Franekić-Čolić, Jasna; Coale, Kenneth; Epel, David; Hamdoun, Amro

    2009-01-01

    Mercuric compounds are persistent global pollutants that accumulate in marine organisms and in humans who consume them. While the chemical cycles and speciation of mercury in the oceans are relatively well described, the cellular mechanisms that govern which forms of mercury accumulate in cells and why they persist are less understood. In this study we examined the role of multidrug efflux transport in the differential accumulation of inorganic (HgCl2) and organic (CH3HgCl) mercury in sea urc...

  7. Dry matter accumulation in citrus fruit is not limited by transport capacity of the pedicel.

    Garcia-Luis, A; Oliveira, M E M; Bordon, Y; Siqueira, D L; Tominaga, S; Guardiola, J L

    2002-12-01

    The vascularization of the pedicel in Marisol clementine (Citrus clementina Hort. ex Tanaka) has been characterized in relation to fruit growth. Phloem and xylem formation occurred during the first half of the period of fruit growth. Phloem cross-sectional area reached its maximum value by the end of fruitlet abscission, 78 d after anthesis (DAA), shortly after the rate of accumulation of dry matter in fruitlets reached its maximum value. Secondary xylem formation occurred until day 93, well after the end of fruitlet abscission. At fruit maturity, xylem accounted for 42-46 % of the cross-section of the pedicel. Vessels differentiated in this late-formed xylem. Formation of phloem and early xylem was directly related to fruitlet size (and growth rate). Differences in the rate of formation of conductive tissues in the pedicel of the developing fruitlets followed rather than preceded the differences in growth rate. Specific mass transfer (SMT) in the phloem was highest in the fastest growing fruitlets, and peaked during the late stages of fruitlet abscission (72-78 DAA) and during the main period of fruit growth (107-121 DAA). Application of a synthetic auxin to developing fruits, either at the end of flowering (2,4-D) or by day 64 after flowering (2,4-DP), increased the growth rate of the fruit and fruit size at maturity (8-13 % increase in fruit diameter at maturity). These auxin applications also enhanced the formation of conductive tissues in the pedicel, with a specific effect on phloem formation. Applying auxin at flowering resulted in a reduction in the phloem SMT by days 72-78, whereas auxin application on day 64 increased this parameter. Despite this difference in behaviour, which resulted from the different time-course of the growth response of the fruit to auxin applications, these applications increased fruit size to a similar extent. Severing 37 % of the phloem of the pedicel during the main period of fruit growth resulted in an increase in the specific

  8. Conjugated Linoleic Acid Accumulation via 10-Hydroxy-12-Octadecaenoic Acid during Microaerobic Transformation of Linoleic Acid by Lactobacillus acidophilus

    Ogawa, Jun; Matsumura, Kenji; Kishino, Shigenobu; Omura, Yoriko; Shimizu, Sakayu

    2001-01-01

    Specific isomers of conjugated linoleic acid (CLA), a fatty acid with potentially beneficial physiological and anticarcinogenic effects, were efficiently produced from linoleic acid by washed cells of Lactobacillus acidophilus AKU 1137 under microaerobic conditions, and the metabolic pathway of CLA production from linoleic acid is explained for the first time. The CLA isomers produced were identified as cis-9, trans-11- or trans-9, cis-11-octadecadienoic acid and trans-9, trans-11-octadecadie...

  9. Regulation and limitations to fatty acid oxidation during exercise

    Jeppesen, Jacob; Kiens, Bente

    2012-01-01

    turn is trapped by carnitine. This will lead to less availability of free carnitine for fatty acid transport into mitochondria. This review summarizes our present view on how FA metabolism is regulated during exercise with a special focus on the limitations in FA oxidation in the transition from...

  10. Improved cadmium uptake and accumulation in the hyperaccumulator Sedum alfredii: the impact of citric acid and tartaric acid.

    Lu, Ling-li; Tian, Sheng-ke; Yang, Xiao-e; Peng, Hong-yun; Li, Ting-qiang

    2013-02-01

    The elucidation of a natural strategy for metal hyperaccumulation enables the rational design of technologies for the clean-up of metal-contaminated soils. Organic acid has been suggested to be involved in toxic metallic element tolerance, translocation, and accumulation in plants. The impact of exogenous organic acids on cadmium (Cd) uptake and translocation in the zinc (Zn)/Cd co-hyperaccumulator Sedum alfredii was investigated in the present study. By the addition of organic acids, short-term (2 h) root uptake of (109)Cd increased significantly, and higher (109)Cd contents in roots and shoots were noted 24 h after uptake, when compared to controls. About 85% of the (109)Cd taken up was distributed to the shoots in plants with citric acid (CA) treatments, as compared with 75% within controls. No such effect was observed for tartaric acid (TA). Reduced growth under Cd stress was significantly alleviated by low CA. Long-term application of the two organic acids both resulted in elevated Cd in plants, but the effects varied with exposure time and levels. The results imply that CA may be involved in the processes of Cd uptake, translocation and tolerance in S. alfredii, whereas the impact of TA is mainly on the root uptake of Cd. PMID:23365009

  11. Improved cadmium uptake and accumulation in the hyperaccumulator Sedum alfredii:the impact of citric acid and tartaric acid

    Ling-li LU; Sheng-ke TIAN; Xiao-e YANG; Hong-yun PENG; Ting-qiang LI

    2013-01-01

    The elucidation of a natural strategy for metal hyperaccumulation enables the rational design of technologies for the clean-up of metal-contaminated soils.Organic acid has been suggested to be involved in toxic metallic element tolerance,translocation,and accumulation in plants.The impact of exogenous organic acids on cadmium(Cd)uptake and translocation in the zinc(Zn)/Cd co-hyperaccumulator Sedum alfredii was investigated in the present study.By the addition of organic acids,short-term(2 h)root uptake of 109Cd increased significantly,and higher 109Cd contents in roots and shoots were noted 24 h after uptake,when compared to controls.About 85% of the 109Cd taken up was distributed to the shoots in plants with citric acid(CA)treatments,as compared with 75% within controls.No such effect was observed for tartaric acid(TA).Reduced growth under Cd stress was significantly alleviated by low CA.Long-term application of the two organic acids both resulted in elevated Cd in plants,but the effects varied with exposure time and levels.The results imply that CA may be involved in the processes of Cd uptake,translocation and tolerance in S.alfredii,whereas the impact of TA is mainly on the root uptake of Cd.

  12. Improved cadmium uptake and accumulation in the hyperaccumulator Sedum alfredii: the impact of citric acid and tartaric acid* #

    Lu, Ling-li; Tian, Sheng-ke; Yang, Xiao-e; Peng, Hong-yun; Li, Ting-qiang

    2013-01-01

    The elucidation of a natural strategy for metal hyperaccumulation enables the rational design of technologies for the clean-up of metal-contaminated soils. Organic acid has been suggested to be involved in toxic metallic element tolerance, translocation, and accumulation in plants. The impact of exogenous organic acids on cadmium (Cd) uptake and translocation in the zinc (Zn)/Cd co-hyperaccumulator Sedum alfredii was investigated in the present study. By the addition of organic acids, short-term (2 h) root uptake of 109Cd increased significantly, and higher 109Cd contents in roots and shoots were noted 24 h after uptake, when compared to controls. About 85% of the 109Cd taken up was distributed to the shoots in plants with citric acid (CA) treatments, as compared with 75% within controls. No such effect was observed for tartaric acid (TA). Reduced growth under Cd stress was significantly alleviated by low CA. Long-term application of the two organic acids both resulted in elevated Cd in plants, but the effects varied with exposure time and levels. The results imply that CA may be involved in the processes of Cd uptake, translocation and tolerance in S. alfredii, whereas the impact of TA is mainly on the root uptake of Cd. PMID:23365009

  13. ACCUMULATION OF POLYHYDROXYALKANOIC ACIDS BY AZOTOBACTER CHROOCOCCUM MAL-201 FROM ORGANIC WASTE

    Soma Pal Saha

    2013-08-01

    Full Text Available Azotobacter chroococcum MAL-201 (MTCC 3853, a free-living nitrogen-fixing bacterium accumulated intracellular poly(3-hydroxybutyric acid [P(3HB] accounting 69% of cell dry weight (CDW when grown in nitrogrn-free Stockdale medium containing 2% (w/v glucose. It also produced copolymer of poly(3-hydroxybutyrate co-3-hydroxyvalerate [P(3HB-co-3HV] using glucose as primary carbon source and valerate cas cosubstrate. To make the polymer production cost effective four types of waste material of different origin were tested for growth and polymer production. Stockdale medium supplemented with 1% (w/v waste materials failed to yield good growth and polymer accumulation. Two–step cultivation was adopted for better growth and enhanced polymer accumulation. The candy factory waste was most suitable for synthesis of P(3HB accounting 17.8 and 40.58% using single and two-step cultivation conditions respectively. Wastes of domestic and poultry origin produced P(3HB-co-3HV with 3HV content 28.8 and 21.5 mol% respectively in two-step cultivation. Increase concentration of these wastes resulted in further upliftment of 3HV content of polymer with reduced growth and polymer accumulation. However, at optimum incubation the strain MAL-201 cells accumulated P(3HB 48.5% of CDW (at 40h from candy factory waste and P(3HB-co-3HV 24.75 % of CDW with 3HV 34.65 mol % from domestic waste. Intrinsic viscosity, molecular weight and thermal degradation of the polymers accumulated in the cells grown in glucose, glucose with valerate and glucose with waste were compared.

  14. Increased accumulation of the lipophilic cation tetraphenylphosphonium+ by cyclopiazonic acid-treated renal epithelial cells

    Pig kidney renal epithelial cells (LLC-PK1) in culture were used to determine the effects of cyclopiazonic acid (CPA) on the uptake of the transmembrane potential probe, [3H]tetraphenylphosphonium bromide (TPP+). CPA had a significant stimulatory effect on TPP+ accumulation, which occurred in a dose-related manner. TPP+ accumulation in the presence of CPA was significantly reduced by high-potassium media (HK) and carbonylcyanide m-chlorophenylhydrazone (CCCP), but neither HK nor the protonophore CCCP, could completely abolish the stimulatory effect of CPA. The apparent transmembrane potential difference, calculated based on the difference in accumulation of TPP+ in low-potassium and HK media, ranged from -55.9 to -85.7 mV for control cells and -89.4 to -109.0 mV for CPA-treated cells (20 mg CPA/I). The mechanism of CPA stimulation of TPP+ accumulation was not known. However, it was hypothesized that the effect could be a result of alterations in ion pumps or altered membrane permeability

  15. Monochloroacetic acid lethality in the rat in relation to lactic acid accumulation in the cerebrospinal fluid

    Potential antidotes for human exposure to monochloroacetic acid (MCA) were evaluated using a rodent model. Dichloroacetic acid (DCA) and phenobarbital (PB) but not ethanol or phenytoin, were found to be effective antidotes to monochloroacetic acid (MCA) in rats. DCA (110 mg/kg, ip), administered to rats 15 minutes after a LD-80 of MCA (80 mg/kg, iv), consistently reduced mortality to 0%, while PB reduced mortality to less than 20%. Both DCA and PB were found to be similarly effective in mice. The hypothesis that PB reduces mortality in MCA treated rats by altering the metabolic disposition of MCA was evaluated and rejected. Administration of PB to rats treated with a lethal dose of [14C]MCA did not alter the concentrations of MCA or its metabolites in plasma or cerebrospinal fluid (CSF), or the extent of covalent binding between radioactivity equivalent to [14C]MCA and brain proteins. The relationship between altered blood-brain barrier permeability and death in MCA treated rats was investigated. Treatment with MCA (80 mg/kg, iv) was associated with a significant (50%) increase in the permeability of the rat blood-brain barrier to [125I]BSA. The effect was not altered by treatment with PB, however, suggesting that altered blood-brain barrier permeability does not have an important role in the lethal effect of MCA in rats. The effect of MCA on brain carbohydrate metabolism in vivo was investigated. CSF and blood lactic acid concentrations increased in MCA treated rats, and the increase in CSF levels was dose related. In individual MCA treated rats, CSF lactate concentrations paralleled the time course of ataxia and a discrete threshold for death (18 mmol/L) was observed. The relationship between excess brain lactate levels and death in MCA treated rats was investigated further

  16. Trade-Off between Growth and Carbohydrate Accumulation in Nutrient-Limited Arthrospira sp. PCC 8005 Studied by Integrating Transcriptomic and Proteomic Approaches.

    Orily Depraetere

    Full Text Available Cyanobacteria have a strong potential for biofuel production due to their ability to accumulate large amounts of carbohydrates. Nitrogen (N stress can be used to increase the content of carbohydrates in the biomass, but it is expected to reduce biomass productivity. To study this trade-off between carbohydrate accumulation and biomass productivity, we characterized the biomass productivity, biomass composition as well as the transcriptome and proteome of the cyanobacterium Arthrospira sp. PCC 8005 cultured under N-limiting and N-replete conditions. N limitation resulted in a large increase in the carbohydrate content of the biomass (from 14 to 74% and a decrease in the protein content (from 37 to 10%. Analyses of fatty acids indicated that no lipids were accumulated under N-limited conditions. Nevertheless, it did not affect the biomass productivity of the culture up to five days after N was depleted from the culture medium. Transcriptomic and proteomic analysis indicated that de novo protein synthesis was down-regulated in the N-limited culture. Proteins were degraded and partly converted into carbohydrates through gluconeogenesis. Cellular N derived from protein degradation was recycled through the TCA and GS-GOGAT cycles. In addition, photosynthetic energy production and carbon fixation were both down-regulated, while glycogen synthesis was up-regulated. Our results suggested that N limitation resulted in a redirection of photosynthetic energy from protein synthesis to glycogen synthesis. The fact that glycogen synthesis has a lower energy demand than protein synthesis might explain why Arthrospira is able to achieve a similar biomass productivity under N-limited as under N-replete conditions despite the fact that photosynthetic energy production was impaired by N limitation.

  17. Effect of orthosilicic acid on the accumulation of trace metals by the pond snail Lymnaea stagnalis

    Silicon (Si) has a marked affinity for aluminium (Al(III)), but not other trace metals such as cadmium (Cd(II)) and zinc (Zn(II)). Exogenous orthosilicic acid (Si(OH)4) ameliorates the toxicity of Al(III) to the pond snail Lymnaea stagnalis, but its mechanism of action is unclear. Here, studies were conducted to ascertain whether interaction between orthosilicic acid and Al(III) occurs in the water column to prevent Al(III) uptake, or in the tissues to reduce the toxicity of accumulated metal. Silicon did not reduce the accumulation of Al(III) by the digestive gland (the main 'sink' for trace metals in L. stagnalis) following exposure of the snail for 30 days to 500 μg l-1 added Al(III) and 13-fold molar excess of orthosilicic acid. However, Si concentrations correlated well with Al(III) levels in the digestive gland (R2=0.77), giving a ratio of 2.5:1 (Al(III):Si). Exposure to Zn(II) or Cd(II) and 13-fold molar excess of orthosilicic acid did not prevent uptake of these metals, or result in a correlation between metal and Si concentrations of the snail digestive gland. These data show that aquated orthosilicic acid does not prevent Al(III) accumulation by L. stagnalis. However, following exposure, the ratio of Al(III) to Si in the digestive gland is suggestive of the early formation of hydroxyaluminosilicates, probably proto-imogolites (2-3:1 Al(III):Si). Whether hydroxyaluminates are formed ex vivo in the water column and taken up by snails into the digestive gland, or formed in situ within the digestive gland remains to be established. Either way, orthosilicic acid clearly prevents the in vivo toxicity of Al(III) rather than reducing its uptake. Silicon appears to have an important role in the handling Al(III) by the pond snail which may also have wider relevance in understanding the role of Si in ameliorating Al(III) toxicity

  18. Ascorbic acid accumulates as a defense response to Turnip mosaic virus in resistant Brassica rapa cultivars.

    Fujiwara, Ayaka; Togawa, Satoko; Hikawa, Takahiro; Matsuura, Hideyuki; Masuta, Chikara; Inukai, Tsuyoshi

    2016-07-01

    We initially observed that Brassica rapa cultivars containing the Turnip mosaic virus (TuMV) resistance gene, Rnt1-1, accumulated a high level of endogenous ascorbic acid (AS) and dehydroascobic acid (DHA) when infected with TuMV. We here hypothesized a possible contribution of an elevated level of AS+DHA (TAA) to the Rnt1-1-mediated resistance, and conducted a series of experiments using B. rapa and Arabidopsis plants. The application of l-galactose (the key substrate in AS synthesis) to a susceptible cultivar could increase the TAA level ~2-fold, and simultaneously lead to some degree of enhanced viral resistance. To confirm some positive correlation between TAA levels and viral resistance, we analyzed two Arabidopsis knockout mutants (ao and vtc1) in the AS pathways; the TAA levels were significantly increased and decreased in ao and vtc1 plants, respectively. While the ao plants showed enhanced resistance to TuMV, vtc1 plants were more susceptible than the control, supporting our hypothesis. When we analyzed the expression profiles of the genes involved in the AS pathways upon TuMV infection, we found that the observed TAA increase was mainly brought about by the reduction of AS oxidation and activation of AS recycling. We then investigated the secondary signals that regulate endogenous TAA levels in response to viral infection, and found that jasmonic acid (JA) might play an important role in TAA accumulation. In conclusion, we reason that the elevated TAA accumulation in B. rapa plants would be at least partly mediated by the JA-dependent signaling pathway and may significantly contribute to viral resistance. PMID:27255930

  19. Comparative proteomic analysis of engineered Saccharomyces cerevisiae with enhanced free fatty acid accumulation.

    Chen, Liwei; Lee, Jaslyn Jie Lin; Zhang, Jianhua; Chen, Wei Ning

    2016-02-01

    The engineered Saccharomyces cerevisiae strain △faa1△faa4 [Acot5s] was demonstrated to accumulate more free fatty acids (FFA) previously. Here, comparative proteomic analysis was performed to get a global overview of metabolic regulation in the strain. Over 500 proteins were identified, and 82 of those proteins were found to change significantly in the engineered strains. Proteins involved in glycolysis, acetate metabolism, fatty acid synthesis, TCA cycle, glyoxylate cycle, the pentose phosphate pathway, respiration, transportation, and stress response were found to be upregulated in △faa1△faa4 [Acot5s] as compared to the wild type. On the other hand, proteins involved in glycerol, ethanol, ergosterol, and cell wall synthesis were downregulated. Taken together with our metabolite analysis, our results showed that the disruption of Faa1 and Faa4 and expression of Acot5s in the engineered strain △faa1△faa4 [Acot5s] not only relieved the feedback inhibition of fatty acyl-CoAs on fatty acid synthesis, but also caused a major metabolic rearrangement. The rearrangement redirected carbon flux toward the pathways which generate the essential substrates and cofactors for fatty acid synthesis, such as acetyl-CoA, ATP, and NADPH. Therefore, our results help shed light on the mechanism for the increased production of fatty acids in the engineered strains, which is useful in providing information for future studies in biofuel production. PMID:26450510

  20. ACCUMULATION OF POLYHYDROXYALKANOIC ACIDS BY AZOTOBACTER CHROOCOCCUM MAL-201 FROM ORGANIC WASTE

    Soma Pal Saha; A. Patra; P. B. Ghosh; A.K. Paul

    2013-01-01

    Azotobacter chroococcum MAL-201 (MTCC 3853), a free-living nitrogen-fixing bacterium accumulated intracellular poly(3-hydroxybutyric acid) [P(3HB)] accounting 69% of cell dry weight (CDW) when grown in nitrogrn-free Stockdale medium containing 2% (w/v) glucose. It also produced copolymer of poly(3-hydroxybutyrate co-3-hydroxyvalerate) [P(3HB-co-3HV)] using glucose as primary carbon source and valerate cas cosubstrate. To make the polymer production cost effective four types of waste material ...

  1. Determination of dopamine with improved sensitivity by exploiting an accumulation effect at a nano-gold electrode modified with poly(sulfosalicylic acid)

    We describe a glassy carbon electrode modified with nano-gold and a film of poly(sulfosalicylic acid) that was obtained by electropolymerization of sulfosalicylic acid. The electrochemical characteristics of the electrode were investigated by using (a) the anionic hexacyanoferrate, and (b) the cationic ruthenium-trisbipyridyl systems as redox probes. The electrode displayed selective and enhanced electroanalytical response towards dopamine (DA), obviously because DA (which is cationic) is accumulated at the electrode, while anions such as ascorbic acid (AA) do not and in fact are being repelled. A 2000-fold molar excess of AA is tolerated after a 120-s accumulation time followed by stripping detection at pH 6. 5. Response is linear with the concentration of DA in the range from 0. 05 to 5 μM, and the detection limit is 7 nM (at an S/N of 3) even in the presence of 100 μM concentrations of AA. (author)

  2. Vermicompost humic acids modulate the accumulation and metabolism of ROS in rice plants.

    García, Andrés Calderín; Santos, Leandro Azevedo; de Souza, Luiz Gilberto Ambrósio; Tavares, Orlando Carlos Huertas; Zonta, Everaldo; Gomes, Ernane Tarcisio Martins; García-Mina, José Maria; Berbara, Ricardo Luis Louro

    2016-03-15

    This work aims to determine the reactive oxygen species (ROS) accumulation, gene expression, anti-oxidant enzyme activity, and derived effects on membrane lipid peroxidation and certain stress markers (proline and malondialdehyde-MDA) in the roots of unstressed and PEG-stressed rice plants associated with vermicompost humic acid (VCHA) application. The results show that the application of VCHA to the roots of unstressed rice plants caused a slight but significant increase in root ROS accumulation and the gene expression and activity of the major anti-oxidant enzymes (superoxide dismutase and peroxidase). This action did not have negative effects on root development, and an increase in both root growth and root proliferation occurred. However, the root proline and MDA concentrations and the root permeability results indicate the development of a type of mild stress associated with VCHA application. When VCHA was applied to PEG-stressed plants, a clear alleviation of the inhibition in root development linked to PEG-mediated osmotic stress was observed. This was associated with a reduction in root ROS production and anti-oxidant enzymatic activity caused by osmotic stress. This alleviation of stress caused by VCHA was also reflected as a reduction in the PEG-mediated concentration of MDA in the root as well as root permeability. In summary, the beneficial action of VCHA on the root development of unstressed or PEG-stressed rice plants clearly involves the modulation of ROS accumulation in roots. PMID:26851887

  3. Accumulation of Flavonols over Hydroxycinnamic Acids Favors Oxidative Damage Protection under Abiotic Stress

    Martinez, Vicente; Mestre, Teresa C.; Rubio, Francisco; Girones-Vilaplana, Amadeo; Moreno, Diego A.; Mittler, Ron; Rivero, Rosa M.

    2016-01-01

    Efficient detoxification of reactive oxygen species (ROS) is thought to play a key role in enhancing the tolerance of plants to abiotic stresses. Although multiple pathways, enzymes, and antioxidants are present in plants, their exact roles during different stress responses remain unclear. Here, we report on the characterization of the different antioxidant mechanisms of tomato plants subjected to heat stress, salinity stress, or a combination of both stresses. All the treatments applied induced an increase of oxidative stress, with the salinity treatment being the most aggressive, resulting in plants with the lowest biomass, and the highest levels of H2O2 accumulation, lipid peroxidation, and protein oxidation. However, the results obtained from the transcript expression study and enzymatic activities related to the ascorbate-glutathione pathway did not fully explain the differences in the oxidative damage observed between salinity and the combination of salinity and heat. An exhaustive metabolomics study revealed the differential accumulation of phenolic compounds depending on the type of abiotic stress applied. An analysis at gene and enzyme levels of the phenylpropanoid metabolism concluded that under conditions where flavonols accumulated to a greater degree as compared to hydroxycinnamic acids, the oxidative damage was lower, highlighting the importance of flavonols as powerful antioxidants, and their role in abiotic stress tolerance. PMID:27379130

  4. Transcripts for genes encoding soluble acid invertase and sucrose synthase accumulate in root tip and cortical cells containing mycorrhizal arbuscules.

    Blee, Kristopher A; Anderson, Anne J

    2002-09-01

    Arbuscule formation by the arbuscular mycorrhizal fungus Glomus intraradices (Schenck & Smith) was limited to cortical cells immediately adjacent to the endodermis. Because these cortical cells are the first to intercept photosynthate exiting the vascular cylinder, transcript levels for sucrose metabolizing-enzymes were compared between mycorrhizal and non-mycorrhizal roots. The probes corresponded to genes encoding a soluble acid invertase with potential vacuolar targeting, which we generated from Phaseolus vulgaris roots, a Rhizobium-responsive sucrose synthase of soybean and a cell wall acid invertase of carrot. Transcripts in non-mycorrhizal roots were developmentally regulated and abundant in the root tips for all three probes but in differentiated roots of P. vulgaris they were predominantly located in phloem tissues for sucrose synthase or the endodermis and phloem for soluble acid invertase. In mycorrhizal roots increased accumulations of transcripts for sucrose synthase and vacuolar invertase were both observed in the same cortical cells bearing arbuscules that fluoresce. There was no effect on the expression of the cell wall invertase gene in fluorescent carrot cells containing arbuscules. Thus, it appears that presence of the fungal hyphae in the fluorescent arbusculated cell stimulates discrete alterations in expression of sucrose metabolizing enzymes to increase the sink potential of the cell. PMID:12175013

  5. Electrochemical antimony removal from accumulator acid: Results from removal trials in laboratory cells

    Highlights: ► In non-divided cells, antimony did not deposit at cathode due to oxidation of Sb(III) at anode. ► Copper and graphite were found to be the most suitable electrode materials for antimony deposition. ► Sb species covering electrode lowers deposition efficiency with time. ► Thus, periodical renewal of cathode material is necessary. ► Calculated specific electroenergy consumption was relatively high. ► In contrast, absolute energy consumption was low due to small quantities of antimony removed. - Abstract: Regeneration of spent accumulator acid could be an alternative process for crystallization, neutralisation and disposal. Therefore, for the first time in a study of the possibilities of electrochemical removal of antimony and accumulator acid regeneration on a laboratory scale, two synthetic and several real systems containing sulfuric acid of concentrations ranging between 28% and 36%, and antimony species were tested. Discontinuous electrochemical reactors with anion exchange membranes were successfully used in these experiments, which were conducted at a temperature of 35 °C. Removal of antimony using cells that were not divided by a separator, however, was not possible. In selected experiments, by varying the electrode material, type of electrolyte, and cell current, the concentration of antimony could be reduced from the range of 5 ppm to 0.15 ppm. This resulted in current efficiencies between 0.00002% and 0.001%, and in specific electroenergy demands between 100 Wh L−1 and 2000 Wh L−1. In other experiments on substances with antimony contents up to 3500 mg L−1, the current efficiencies obtained were more than a thousandfold higher. In contrast to the formally high relative energy consumption parameters absolute demand parameters are relatively small and favour the electrochemical method in small scale application. Besides plate electrodes, 3D-cathodes were used. Copper- and graphite cathodes produced the best results.

  6. Presystemic branchial metabolism limits di-2-ethylhexyl phthalate accumulation in fish

    Despite the high lipophilicity of di-2-ethylhexyl phthalate (DEHP), fish do not extensively accumulate this ubiquitous environmental contaminant. Experiments with rainbow trout (Salmo gairdneri) fitted with an indwelling cannula showed that the majority of [14C]DEHP did not reach the systemic circulation of the fish, but was present in the exposure water as metabolites. Pharmacokinetic analysis, using a compartmental model that included the gill as a separate metabolic compartment, indicated that DEHP was extensively metabolized as it diffused from water to blood. Isolated perfused gill arches of trout metabolized DEHP in the exposure bath to monoethylhexyl phthalate, demonstrating the ability of the gill to prevent DEHP entry into the fish. The relationship between metabolic clearance and tissue perfusion further suggests that metabolism in the gill can play an important role in determining the accumulation and toxicity of organic chemical pollutants in fish

  7. Jasmonic Acid Effect on the Fatty Acid and Terpenoid Indole Alkaloid Accumulation in Cell Suspension Cultures of Catharanthus roseus

    Guitele Dalia Goldhaber-Pasillas

    2014-07-01

    Full Text Available The stress response after jasmonic acid (JA treatment was studied in cell suspension cultures of Catharanthus roseus. The effect of JA on the primary and secondary metabolism was based on changes in profiles of fatty acids (FA and terpenoid indole alkaloids (TIA. According to multivariate data analyses (MVDA, three major time events were observed and characterized according to the variations of specific FA and TIA: after 0–30 min of induction FA such as C18:1, C20:0, C22:0 and C24:0 were highly induced by JA; 90–360 min after treatment was characterized by variations of C14:0 and C15:0; and 1440 min after induction JA had the largest effect on both group of metabolites were C18:1, C18:2, C18:3, C16:0, C20:0, C22:0, C24:0, catharanthine, tabersonine-like 1, serpentine, tabersonine and ajmalicine-like had the most significant variations. These results unambiguously demonstrate the profound effect of JA particularly on the accumulation of its own precursor, C18:3 and the accumulation of TIA, which can be considered as late stress response events to JA since they occurred only after 1440 min. These observations show that the early events in the JA response do not involve the de novo biosynthesis of neither its own precursor nor TIA, but is due to an already present biochemical system.

  8. Jasmonic acid effect on the fatty acid and terpenoid indole alkaloid accumulation in cell suspension cultures of Catharanthus roseus.

    Goldhaber-Pasillas, Guitele Dalia; Mustafa, Natali Rianika; Verpoorte, Robert

    2014-01-01

    The stress response after jasmonic acid (JA) treatment was studied in cell suspension cultures of Catharanthus roseus. The effect of JA on the primary and secondary metabolism was based on changes in profiles of fatty acids (FA) and terpenoid indole alkaloids (TIA). According to multivariate data analyses (MVDA), three major time events were observed and characterized according to the variations of specific FA and TIA: after 0-30 min of induction FA such as C18:1, C20:0, C22:0 and C24:0 were highly induced by JA; 90-360 min after treatment was characterized by variations of C14:0 and C15:0; and 1440 min after induction JA had the largest effect on both group of metabolites were C18:1, C18:2, C18:3, C16:0, C20:0, C22:0, C24:0, catharanthine, tabersonine-like 1, serpentine, tabersonine and ajmalicine-like had the most significant variations. These results unambiguously demonstrate the profound effect of JA particularly on the accumulation of its own precursor, C18:3 and the accumulation of TIA, which can be considered as late stress response events to JA since they occurred only after 1440 min. These observations show that the early events in the JA response do not involve the de novo biosynthesis of neither its own precursor nor TIA, but is due to an already present biochemical system. PMID:25029072

  9. Strigolactone regulates anthocyanin accumulation, acid phosphatases production and plant growth under low phosphate condition in Arabidopsis.

    Shinsaku Ito

    Full Text Available Phosphate is an essential macronutrient in plant growth and development; however, the concentration of inorganic phosphate (Pi in soil is often suboptimal for crop performance. Accordingly, plants have developed physiological strategies to adapt to low Pi availability. Here, we report that typical Pi starvation responses in Arabidopsis are partially dependent on the strigolactone (SL signaling pathway. SL treatment induced root hair elongation, anthocyanin accumulation, activation of acid phosphatase, and reduced plant weight, which are characteristic responses to phosphate starvation. Furthermore, the expression profile of SL-response genes correlated with the expression of genes induced by Pi starvation. These results suggest a potential overlap between SL signaling and Pi starvation signaling pathways in plants.

  10. Effect of Nitrogen Sources on the Growth and Docosahexaenoic Acid Accumulation in Crypthecodinium cohnii

    Wang Jufang; Wu Haizhen; Liang Shizhong; Chen Feng

    2002-01-01

    The effect of various nitrogen sources on the growth and docosahexaenoic acid (DHA) yield is determined in Crypthecodinium cohnii ATCC30556. Single nitrogen tryptone and peptone are suitable to growth, the dry weight biomass is up to 2.78 g/L and 2.70g/L respectively on medium containing 0.34 g/L nitrogen. Peptone is a favorable nitrogen source for DHA accumulation, DHA yield increases up to 338.56 mg/L. Using peptone and KNO3 as a multiple nitrogen source, the highest biomass and DHA yield are obtained from media containing 0.34 g/L nitrogen in which the ratio of peptone-N:NO3--N is 1:2,and the biomass and DHA yield are 2.98 g/L(DW) and 527.97mg/L respectively.

  11. Salicylic acid reduces napropamide toxicity by preventing its accumulation in rapeseed (Brassica napus L.).

    Cui, Jing; Zhang, Rui; Wu, Guo Lin; Zhu, Hong Mei; Yang, Hong

    2010-07-01

    Napropamide is a widely used herbicide for controlling weeds in crop production. However, extensive use of the herbicide has led to its accumulation in ecosystems, thus causing toxicity to crops and reducing crop production and quality. Salicylic acid (SA) plays multiple roles in regulating plant adaptive responses to biotic and environmental stresses. However, whether SA regulates plant response to herbicides (or pesticides) was unknown. In this study, we investigated the effect of SA on herbicide napropamide accumulation and biological processes in rapeseed (Brassica napus). Plants exposed to 8 mg kg(-1) napropamide showed growth stunt and oxidative damage. Treatment with 0.1 mM SA improved growth and reduced napropamide levels in plants. Treatment with SA also decreased the abundance of O (2) (-.) and H(2)O(2) as well as activities of superoxide dismutase (SOD), catalase (CAT), and ascorbate peroxidase (APX), and increased activities of guaiacol peroxidase (POD) and glutathione-S-transferase (GST) in napropamide-exposed plants. Analysis of SOD, CAT, and POD activities using nondenaturing polyacrylamide gel electrophoresis (PAGE) confirmed the results. These results may help to understand how SA regulates plant response to organic contaminants and provide a basis to control herbicide/pesticide contamination in crop production. PMID:19967348

  12. Retinoic acid induces nuclear accumulation of Raf1 during differentiation of HL-60 cells

    Smith, James; Bunaciu, Rodica P.; Reiterer, Gudrun [Department of Biomedical Sciences, T4-008 VRT, Cornell University, Ithaca, NY 14853 (United States); Coder, David; George, Thaddeus [Amnis Corporation, Seattle, Washington (United States); Asaly, Michael [Department of Biomedical Sciences, T4-008 VRT, Cornell University, Ithaca, NY 14853 (United States); Yen, Andrew, E-mail: ay13@cornell.edu [Department of Biomedical Sciences, T4-008 VRT, Cornell University, Ithaca, NY 14853 (United States)

    2009-08-01

    All trans-retinoic acid (RA) is a standard therapeutic agent used in differentiation induction therapy treatment of acute promyelocytic leukemia (APL). RA and its metabolites use a diverse set of signal transduction pathways during the differentiation program. In addition to the direct transcriptional targets of the nuclear RAR and RXR receptors, signals derived from membrane receptors and the Raf-MEK-ERK pathway are required. Raf1 phosphorylation and the prolonged activation of Raf1 persisting during the entire differentiation process are required for RA-dependent differentiation of HL-60 cells. Here we identify a nuclear redistribution of Raf1 during the RA-induced differentiation of HL-60 cells. In addition, the nuclear accumulation of Raf1 correlates with an increase in Raf1 phosphorylated at serine 621. The serine 621 phosphorylated Raf1 is predominantly localized in the nucleus. The RA-dependent nuclear accumulation of Raf1 suggests a novel nuclear role for Raf1 during the differentiation process.

  13. Accumulation of some metals by legumes and their extractability from acid mine spoils. [USA - Alabama

    Taylor, R.W.; Ibeabuchi, I.O.; Sistani, K.R.; Shuford, J.W. (Alabama A M University, Normal, AL (USA). Dept. of Plant and Soil Science)

    A greenhouse study was conducted to investigate the growth (dry matter yield) of selected legume cover crops; phytoaccumulation of metals such as Zn, Mn, Pb, Cu, Ni, and Al; the extractability of heavy metals from three different Alabama acid mine spoils. The spoils were amended based on soil test recommended levels of N, P, K, Ca and Mg prior to plant growth. Metals were extracted by three extractants (Mehlich 1, DTPA, and 0.1 M HCl) and values correlated with their accumulation by the selected legumes. Among the cover crops, kobe lespedeza {ital Lespedeza striata} (Thung.) Hook and Arn, sericea lespedeza {ital Lespedeza cuneata} (Dum.) G. Don, and red clover (Trifolium pratense L.) did not survive the stressful conditions of the spoils. However, cowpea (Vigna unguiculata L.) followed by Bragg' soybean {ital Glycine max} (L.) Merr. generally produced the highest dry matter yield while accumulating the largest quantity of metals, except Al, from spoils. The extractability of most metals from the spoils was generally in the order of: 0.1 MHCl {gt} DTPA. Mehlich 1 did not extract Pb and 0.1 M HCl did not extract Ni, whereas DTPA extracted all the metals in a small amount relative to HCl and Mehlich 1. All the extractants were quite effective in removing plant-available Zn from the spoils. In general, the extractants' ability to predict plant-available metals depended on the crop species, spoil type, and extractant used. 28 refs., 4 tabs.

  14. Copper accumulation in vineyard soils: Rhizosphere processes and agronomic practices to limit its toxicity.

    Brunetto, Gustavo; Bastos de Melo, George Wellington; Terzano, Roberto; Del Buono, Daniele; Astolfi, Stefania; Tomasi, Nicola; Pii, Youry; Mimmo, Tanja; Cesco, Stefano

    2016-11-01

    Viticulture represents an important agricultural practice in many countries worldwide. Yet, the continuous use of fungicides has caused copper (Cu) accumulation in soils, which represent a major environmental and toxicological concern. Despite being an important micronutrient, Cu can be a potential toxicant at high concentrations since it may cause morphological, anatomical and physiological changes in plants, decreasing both food productivity and quality. Rhizosphere processes can, however, actively control the uptake and translocation of Cu in plants. In particular, root exudates affecting the chemical, physical and biological characteristics of the rhizosphere, might reduce the availability of Cu in the soil and hence its absorption. In addition, this review will aim at discussing the advantages and disadvantages of agronomic practices, such as liming, the use of pesticides, the application of organic matter, biochar and coal fly ashes, the inoculation with bacteria and/or mycorrhizal fungi and the intercropping, in alleviating Cu toxicity symptoms. PMID:27513550

  15. Xanthurenic acid distribution, transport, accumulation and release in the rat brain.

    Gobaille, Serge; Kemmel, Véronique; Brumaru, Daniel; Dugave, Christophe; Aunis, Dominique; Maitre, Michel

    2008-05-01

    Tryptophan metabolism through the kynurenine pathway leads to several neuroactive compounds, including kynurenic and picolinic acids. Xanthurenic acid (Xa) has been generally considered as a substance with no physiological role but possessing toxic and apoptotic properties. In the present work, we present several findings which support a physiological role for endogenous Xa in synaptic signalling in brain. This substance is present in micromolar amounts in most regions of the rat brain with a heterogeneous distribution. An active vesicular synaptic process inhibited by bafilomycin and nigericin accumulates xanthurenate into pre-synaptic terminals. A neuronal transport, partially dependant on adenosine 5'-triphosphate (ATP), sodium and chloride ions exists in NCB-20 neurons which could participate in the clearance of extracellular xanthurenate. Both transports (neuronal and vesicular) are greatly enhanced by the presence of micromolar amounts of zinc ions. Finally, electrical in vivo stimulation of A10-induced Xa release in the extracellular spaces of the rat prefrontal cortex. This phenomenon is reproduced by veratrine, K+ ions and blocked by EGTA and tetrodotoxin. These results strongly argue for a role for Xa in neurotransmission/neuromodulation in the rat brain, thus providing the existence of specific Xa receptors. PMID:18182052

  16. Genome-wide association mapping identifies a new arsenate reductase enzyme critical for limiting arsenic accumulation in plants.

    Dai-Yin Chao

    2014-12-01

    Full Text Available Inorganic arsenic is a carcinogen, and its ingestion through foods such as rice presents a significant risk to human health. Plants chemically reduce arsenate to arsenite. Using genome-wide association (GWA mapping of loci controlling natural variation in arsenic accumulation in Arabidopsis thaliana allowed us to identify the arsenate reductase required for this reduction, which we named High Arsenic Content 1 (HAC1. Complementation verified the identity of HAC1, and expression in Escherichia coli lacking a functional arsenate reductase confirmed the arsenate reductase activity of HAC1. The HAC1 protein accumulates in the epidermis, the outer cell layer of the root, and also in the pericycle cells surrounding the central vascular tissue. Plants lacking HAC1 lose their ability to efflux arsenite from roots, leading to both increased transport of arsenic into the central vascular tissue and on into the shoot. HAC1 therefore functions to reduce arsenate to arsenite in the outer cell layer of the root, facilitating efflux of arsenic as arsenite back into the soil to limit both its accumulation in the root and transport to the shoot. Arsenate reduction by HAC1 in the pericycle may play a role in limiting arsenic loading into the xylem. Loss of HAC1-encoded arsenic reduction leads to a significant increase in arsenic accumulation in shoots, causing an increased sensitivity to arsenate toxicity. We also confirmed the previous observation that the ACR2 arsenate reductase in A. thaliana plays no detectable role in arsenic metabolism. Furthermore, ACR2 does not interact epistatically with HAC1, since arsenic metabolism in the acr2 hac1 double mutant is disrupted in an identical manner to that described for the hac1 single mutant. Our identification of HAC1 and its associated natural variation provides an important new resource for the development of low arsenic-containing food such as rice.

  17. Engineering alfalfa to accumulate useful caffeic acid derivatives and characterization of hydroxycinnamoyl-CoA transferases from legumes

    Some forages crops, such as red clover, accumulate high levels of caffeic acid derivatives. Oxidation of these o-diphenols to quinones by endogenous polyphenol oxidases (PPOs) and the subsequent reactions of these quinones (probably with endogenous plant proteases) result in a significant reduction ...

  18. Effects of Formulated Fertilizer Synergist on Abscisic Acid Accumulation, Proline Content and Photosynthetic Characteristics of Rice under Drought

    WANG Shao-xian; XIA Shi-tou; PENG Ke-qin; KUANG Feng-chun; CAO Yong; XIAO Lang-tao

    2007-01-01

    To investigate the effects of formulated fertilizer synergist on the drought tolerance in rice, pot experiment was conducted to analyze the photosynthetic characteristics and the accumulation of abscisic acid (ABA) and proline in middle-season rice variety Peiliangyou 93. The synergist could improve the net photosynthetic rate, and coordination between the water loss and the CO2 absorption as well as reduce the harmful effect on photosynthetic process under drought conditions. Under drought, the ABA accumulated massively both in roots and leaves, while the ABA content in roots was far higher than that in leaves. The results indicate that synergist could increase the ABA accumulation, but reduce the proline accumulation in rice plant under drought.

  19. Metformin reduces lipid accumulation in macrophages by inhibiting FOXO1-mediated transcription of fatty acid-binding protein 4

    Objective: The accumulation of lipids in macrophages contributes to the development of atherosclerosis. Strategies to reduce lipid accumulation in macrophages may have therapeutic potential for preventing and treating atherosclerosis and cardiovascular complications. The antidiabetic drug metformin has been reported to reduce lipid accumulation in adipocytes. In this study, we examined the effects of metformin on lipid accumulation in macrophages and investigated the mechanisms involved. Methods and results: We observed that metformin significantly reduced palmitic acid (PA)-induced intracellular lipid accumulation in macrophages. Metformin promoted the expression of carnitine palmitoyltransferase I (CPT-1), while reduced the expression of fatty acid-binding protein 4 (FABP4) which was involved in PA-induced lipid accumulation. Quantitative real-time PCR showed that metformin regulates FABP4 expression at the transcriptional level. We identified forkhead transcription factor FOXO1 as a positive regulator of FABP4 expression. Inhibiting FOXO1 expression with FOXO1 siRNA significantly reduced basal and PA-induced FABP4 expression. Overexpression of wild-type FOXO1 and constitutively active FOXO1 significantly increased FABP4 expression, whereas dominant negative FOXO1 dramatically decreased FABP4 expression. Metformin reduced FABP4 expression by promoting FOXO1 nuclear exclusion and subsequently inhibiting its activity. Conclusions: Taken together, these results suggest that metformin reduces lipid accumulation in macrophages by repressing FOXO1-mediated FABP4 transcription. Thus, metformin may have a protective effect against lipid accumulation in macrophages and may serve as a therapeutic agent for preventing and treating atherosclerosis in metabolic syndrome.

  20. Metformin reduces lipid accumulation in macrophages by inhibiting FOXO1-mediated transcription of fatty acid-binding protein 4

    Song, Jun [Qilu Hospital, Shandong University, Jinan, Shandong (China); Division of Cardiothoracic Surgery, Michael E. DeBakey Department of Surgery, Baylor College of Medicine, Houston, TX (United States); Texas Heart Institute at St. Luke' s Episcopal Hospital, Houston, TX (United States); Ren, Pingping; Zhang, Lin [Division of Cardiothoracic Surgery, Michael E. DeBakey Department of Surgery, Baylor College of Medicine, Houston, TX (United States); Texas Heart Institute at St. Luke' s Episcopal Hospital, Houston, TX (United States); Wang, Xing Li [Qilu Hospital, Shandong University, Jinan, Shandong (China); Division of Cardiothoracic Surgery, Michael E. DeBakey Department of Surgery, Baylor College of Medicine, Houston, TX (United States); Texas Heart Institute at St. Luke' s Episcopal Hospital, Houston, TX (United States); Chen, Li [Qilu Hospital, Shandong University, Jinan, Shandong (China); Shen, Ying H., E-mail: hyshen@bcm.edu [Division of Cardiothoracic Surgery, Michael E. DeBakey Department of Surgery, Baylor College of Medicine, Houston, TX (United States); Texas Heart Institute at St. Luke' s Episcopal Hospital, Houston, TX (United States)

    2010-02-26

    Objective: The accumulation of lipids in macrophages contributes to the development of atherosclerosis. Strategies to reduce lipid accumulation in macrophages may have therapeutic potential for preventing and treating atherosclerosis and cardiovascular complications. The antidiabetic drug metformin has been reported to reduce lipid accumulation in adipocytes. In this study, we examined the effects of metformin on lipid accumulation in macrophages and investigated the mechanisms involved. Methods and results: We observed that metformin significantly reduced palmitic acid (PA)-induced intracellular lipid accumulation in macrophages. Metformin promoted the expression of carnitine palmitoyltransferase I (CPT-1), while reduced the expression of fatty acid-binding protein 4 (FABP4) which was involved in PA-induced lipid accumulation. Quantitative real-time PCR showed that metformin regulates FABP4 expression at the transcriptional level. We identified forkhead transcription factor FOXO1 as a positive regulator of FABP4 expression. Inhibiting FOXO1 expression with FOXO1 siRNA significantly reduced basal and PA-induced FABP4 expression. Overexpression of wild-type FOXO1 and constitutively active FOXO1 significantly increased FABP4 expression, whereas dominant negative FOXO1 dramatically decreased FABP4 expression. Metformin reduced FABP4 expression by promoting FOXO1 nuclear exclusion and subsequently inhibiting its activity. Conclusions: Taken together, these results suggest that metformin reduces lipid accumulation in macrophages by repressing FOXO1-mediated FABP4 transcription. Thus, metformin may have a protective effect against lipid accumulation in macrophages and may serve as a therapeutic agent for preventing and treating atherosclerosis in metabolic syndrome.

  1. Identifying nitrogen limitations to organic sediments accumulation in various vegetation types of arctic tundra (Hornsund, Svalbard)

    Skrzypek, G.; Wojtuń, B.; Hua, Q.; Richter, D.; Jakubas, D.; Wojczulanis-Jakubas, K.; Samecka-Cymerman, A.

    2015-12-01

    Arctic and subarctic regions play important roles in the global carbon balance. However, nitrogen (N) deficiency is a major constraint for organic carbon sequestration in the High Arctic. Hence, the identification of the relative contributions from different N-sources is critical for understanding the constraints that limit tundra growth. The stable nitrogen composition of the three main N-sources and numerous plants were analyzed in ten tundra types in the Fuglebekken catchment (Hornsund Fjord, Svalbard, 77°N 15°E). The percentage of the total tundra N-pool provided by seabirds' feces (colonially breeding, planktivorous Alle alle), ranged from 0-21% in Patterned-ground tundra to 100% in Ornithocoprophilous tundra. The total N-pool utilized by tundra plants in the studied catchment was built in 36% by birds, 38% by atmospheric deposition, and 26% by N2-fixation. The results clearly show that N-pool in the tundra is significantly supplemented by nesting seabirds. Thus, if they experienced substantial negative environmental pressure associated with climate change, it would adversely influence the tundra N-budget [1]. The growth rates and the sediment thickness (climatic conditions but also by birds' contribution to the tundra N-pool. [1] Skrzypek G, Wojtuń B, Richter D, Jakubas D, Wojczulanis-Jakubas K, Samecka-Cymerman A, 2015. Diversification of nitrogen sources in various tundra vegetation types in the high Arctic. PLoS ONE (in review).

  2. Redirection of metabolic flux for high levels of omega-7 monounsaturated fatty acid accumulation in camelina seeds.

    Nguyen, Huu Tam; Park, Hyunwoo; Koster, Karen L; Cahoon, Rebecca E; Nguyen, Hanh T M; Shanklin, John; Clemente, Thomas E; Cahoon, Edgar B

    2015-01-01

    Seed oils enriched in omega-7 monounsaturated fatty acids, including palmitoleic acid (16:1∆9) and cis-vaccenic acid (18:1∆11), have nutraceutical and industrial value for polyethylene production and biofuels. Existing oilseed crops accumulate only small amounts (camelina (Camelina sativa) and soybean (Glycine max) that is dependent on redirection of metabolic flux from the typical ∆9 desaturation of stearoyl (18:0)-acyl carrier protein (ACP) to ∆9 desaturation of palmitoyl (16:0)-acyl carrier protein (ACP) and coenzyme A (CoA). This was achieved by seed-specific co-expression of a mutant ∆9-acyl-ACP and an acyl-CoA desaturase with high specificity for 16:0-ACP and CoA substrates, respectively. This strategy was most effective in camelina where seed oils with ~17% omega-7 monounsaturated fatty acids were obtained. Further increases in omega-7 fatty acid accumulation to 60-65% of the total fatty acids in camelina seeds were achieved by inclusion of seed-specific suppression of 3-keto-acyl-ACP synthase II and the FatB 16:0-ACP thioesterase genes to increase substrate pool sizes of 16:0-ACP for the ∆9-acyl-ACP desaturase and by blocking C18 fatty acid elongation. Seeds from these lines also had total saturated fatty acids reduced to ~5% of the seed oil versus ~12% in seeds of nontransformed plants. Consistent with accumulation of triacylglycerol species with shorter fatty acid chain lengths and increased monounsaturation, seed oils from engineered lines had marked shifts in thermotropic properties that may be of value for biofuel applications. PMID:25065607

  3. The expression of the Cuphea palustris thioesterase CpFatB2 in Yarrowia lipolytica triggers oleic acid accumulation.

    Stefan, Alessandra; Hochkoeppler, Alejandro; Ugolini, Luisa; Lazzeri, Luca; Conte, Emanuele

    2016-01-01

    The conversion of industrial by-products into high-value added compounds is a challenging issue. Crude glycerol, a by-product of the biodiesel production chain, could represent an alternative carbon source for the cultivation of oleaginous yeasts. Here, we developed five minimal synthetic glycerol-based media, with different C/N ratios, and we analyzed the production of biomass and fatty acids by Yarrowia lipolytica Po1g strain. We identified two media at the expense of which Y. lipolytica was able to accumulate ∼5 g L(-1) of biomass and 0.8 g L(-1) of fatty acids (0.16 g of fatty acids per g of dry weight). These optimized media contained 0.5 g L(-1) of urea or ammonium sulfate and 20 g L(-1) of glycerol, and were devoid of yeast extract. Moreover, Y. lipolytica was engineered by inserting the FatB2 gene, coding for the CpFatB2 thioesterase from Cuphea palustris, in order to modify the fatty acid composition towards the accumulation of medium-chain fatty acids. Contrary to the expected, the expression of the heterologous gene increased the production of oleic acid, and concomitantly decreased the level of saturated fatty acids. PMID:26518537

  4. Characterization of major ripening events during softening in grape: turgor, sugar accumulation, abscisic acid metabolism, colour development, and their relationship with growth

    Castellarin, Simone D.; Gambetta, Gregory A.; Wada, Hiroshi; Krasnow, Mark N.; Cramer, Grant R.; Peterlunger, Enrico; Shackel, Kenneth A.; Matthews, Mark A.

    2015-01-01

    Highlight The earliest events in ripening are decreases in turgor, softening, and increases in abscisic acid. Later events integral to regulating colour development include growth, further increases in abscisic acid, and sugar accumulation.

  5. A relaxed eddy accumulation system for measuring vertical fluxes of nitrous acid

    X. Ren

    2011-10-01

    Full Text Available A relaxed eddy accumulation (REA system combined with a nitrous acid (HONO analyzer was developed to measure atmospheric HONO vertical fluxes. The system consists of three major components: (1 a fast-response sonic anemometer measuring both vertical wind velocity and air temperature, (2 a fast-response controlling unit separating air motions into updraft and downdraft samplers by the sign of vertical wind velocity, and (3 a highly sensitive HONO analyzer based on aqueous long path absorption photometry that measures HONO concentrations in the updrafts and downdrafts. A dynamic velocity threshold (±0.5σw, where σw is a standard deviation of the vertical wind velocity was used for valve switching determined by the running means and standard deviations of the vertical wind velocity. Using measured temperature as a tracer and the average values from two field deployments, the flux proportionality coefficient, β, was determined to be 0.42 ± 0.02, in good agreement with the theoretical estimation. The REA system was deployed in two ground-based field studies. In the California Research at the Nexus of Air Quality and Climate Change (CalNex study in Bakersfield, California in summer 2010, measured HONO fluxes appeared to be upward during the day and were close to zero at night. The upward HONO flux was highly correlated to the product of NO2 and solar radiation. During the Biosphere Effects on Aerosols and Photochemistry Experiment (BEARPEX 2009 at Blodgett Forest, California in July 2009, the overall HONO fluxes were small in magnitude and were close to zero. Causes for the different HONO fluxes in the two different environments are briefly discussed.

  6. Glucose phosphorylation is not rate limiting for accumulation of glycogen from glucose in perfused livers from fasted rats

    Incorporation of Glc and Fru into glycogen was measured in perfused livers from 24-h fasted rats using [6-3H]Glc and [U-14C]Fru. For the initial 20 min, livers were perfused with low Glc (2 mM) to deplete hepatic glycogen and were perfused for the following 30 min with various combinations of Glc and Fru. With constant Fru (2 mM), increasing perfusate Glc increased the relative contribution of Glc carbons to glycogen (7.2 +/- 0.4, 34.9 +/- 2.8, and 59.1 +/- 2.7% at 2, 10, and 20 mM Glc, respectively; n = 5 for each). During perfusion with substrate levels seen during refeeding (10 mM Glc, 1.8 mumol/g/min gluconeogenic flux from 2 mM Fru), Fru provided 54.7 +/- 2.7% of the carbons for glycogen, while Glc provided only 34.9 +/- 2.8%, consistent with in vivo estimations. However, the estimated rate of Glc phosphorylation was at least 1.10 +/- 0.11 mumol/g/min, which exceeded by at least 4-fold the glycogen accumulation rate (0.28 +/- 0.04 mumol of glucose/g/min). The total rate of glucose 6-phosphate supply via Glc phosphorylation and gluconeogenesis (2.9 mumol/g/min) exceeded reported in vivo rates of glycogen accumulation during refeeding. Thus, in perfused livers of 24-h fasted rats there is an apparent redundancy in glucose 6-phosphate supply. These results suggest that the rate-limiting step for hepatic glycogen accumulation during refeeding is located between glucose 6-phosphate and glycogen, rather than at the step of Glc phosphorylation or in the gluconeogenic pathway

  7. Prey-induced changes in the accumulation of amino acids and phenolic metabolites in the leaves of Drosera capensis L.

    Kováčik, Jozef; Klejdus, Bořivoj; Stork, František; Hedbavny, Josef

    2012-04-01

    Effect of prey feeding (ants Formica fusca) on the quantitative changes in the accumulation of free amino acids, soluble proteins, phenolic metabolites and mineral nutrients in the leaves of carnivorous plant Drosera capensis was studied. Arginine was the most abundant compound in Drosera leaves, while proline was abundant in ants. The amount of the majority of amino acids and their sum were elevated in the fed leaves after 3 and 21 days, and the same, but with further enhancement after 21 days, was observed in ants. Accumulation of amino acids also increased in young non-fed leaves of fed plants. Soluble proteins decreased in ants, but were not enhanced in fed leaves. This confirms the effectiveness of sundew's enzymatic machinery in digestion of prey and suggests that amino acids are not in situ deposited, but rather are allocated within the plant. The content of total soluble phenols, flavonoids and two selected flavonols (quercetin and kaempferol) was not affected by feeding in Drosera leaves, indicating that their high basal level was sufficient for the plant's metabolism and prey-induced changes were mainly N based. The prey also showed to be an important source of other nutrients besides N, and a stimulation of root uptake of some mineral nutrients is assumed (Mg, Cu, Zn). Accumulation of Ca and Na was not affected by feeding. PMID:21140278

  8. Accumulation fatty acids of in Chlorella vulgaris under heterotrophic conditions in relation to activity of acetyl-CoA carboxylase, temperature, and co-immobilization with Azospirillum brasilense

    Leyva, Luis A.; Bashan, Yoav; Mendoza, Alberto; de-Bashan, Luz E.

    2014-10-01

    The relation between fatty acid accumulation, activity of acetyl-CoA carboxylase (ACC), and consequently lipid accumulation was studied in the microalgae Chlorella vulgaris co-immobilized with the plant growth-promoting bacterium Azospirillum brasilense under dark heterotrophic conditions with Na acetate as a carbon source. In C. vulgaris immobilized alone, cultivation experiments for 6 days showed that ACC activity is directly related to fatty acid accumulation, especially in the last 3 days. In co-immobilization experiments, A. brasilense exerted a significant positive effect over ACC activity, increased the quantity in all nine main fatty acids, increased total lipid accumulation in C. vulgaris, and mitigated negative effects of nonoptimal temperature for growth. No correlation between ACC activity and lipid accumulation in the cells was established for three different temperatures. This study demonstrated that the interaction between A. brasilense and C. vulgaris has a significant effect on fatty acid and lipid accumulation in the microalgae.

  9. Accumulation of fatty acids in Chlorella vulgaris under heterotrophic conditions in relation to activity of acetyl-CoAcarboxylase, temperature, and co-immobilization with Azospirillum brasilense [corrected].

    Leyva, Luis A; Bashan, Yoav; Mendoza, Alberto; de-Bashan, Luz E

    2014-10-01

    The relation between fatty acid accumulation, activity of acetyl-CoA carboxylase (ACC), and consequently lipid accumulation was studied in the microalgae Chlorella vulgaris co-immobilized with the plant growth-promoting bacterium Azospirillum brasilense under dark heterotrophic conditions with Na acetate as a carbon source. In C. vulgaris immobilized alone, cultivation experiments for 6 days showed that ACC activity is directly related to fatty acid accumulation, especially in the last 3 days. In co-immobilization experiments, A. brasilense exerted a significant positive effect over ACC activity, increased the quantity in all nine main fatty acids, increased total lipid accumulation in C. vulgaris, and mitigated negative effects of nonoptimal temperature for growth. No correlation between ACC activity and lipid accumulation in the cells was established for three different temperatures. This study demonstrated that the interaction between A. brasilense and C. vulgaris has a significant effect on fatty acid and lipid accumulation in the microalgae. PMID:25129521

  10. Growth and palmitoleic acid accumulation of filamentous oleaginous microalgae Tribonema minus at varying temperatures and light regimes.

    Wang, Hui; Gao, Lili; Zhou, Wenjun; Liu, Tianzhong

    2016-10-01

    Palmitoleic acid (C16:1Δ9), contributes greatly to human health, industrial chemicals and biodiesel. The filamentous oleaginous microalgae Tribonema sp. has been identified as a highly efficient producer of palmitoleic acid. Temperature and light regime were adapted to regulate the palmitoleic acid content in this study. Strain T. minus was able to grow well at all the tested temperatures, even at 5 °C. The optimum temperature for palmitoleic acid accumulation (54.25 % of total fatty acid) was 25 °C. Moreover, both light intensity and photoperiod affect the growth, lipid content and fatty acid files of T. minus. The culture exposed to 240 μmol photons m(-2) s(-1) with a photoperiod of 24:0 showed the highest biomass (6.87 g L(-1)) and biggest lipid content (61.27 % of dry weight), whereas the most amount of palmitoleic acid (50.47 % of total fatty acid) was detected at 120 μmol photons m(-2) s(-1). These findings make tangible contributions to culture T. minus for commercial production of lipid or palmitoleic acid. PMID:27250652

  11. Saxitoxins and okadaic acid group: accumulation and distribution in invertebrate marine vectors from Southern Chile.

    García, Carlos; Pérez, Francisco; Contreras, Cristóbal; Figueroa, Diego; Barriga, Andrés; López-Rivera, Américo; Araneda, Oscar F; Contreras, Héctor R

    2015-01-01

    Harmful algae blooms (HABs) are the main source of marine toxins in the aquatic environment surrounding the austral fjords in Chile. Huichas Island (Aysén) has an history of HABs spanning more than 30 years, but there is limited investigation of the bioaccumulation of marine toxins in the bivalves and gastropods from the Region of Aysén. In this study, bivalves (Mytilus chilenses, Choromytilus chorus, Aulacomya ater, Gari solida, Tagelus dombeii and Venus antiqua) and carnivorous gastropods (Argobuccinum ranelliformes and Concholepas concholepas) were collected from 28 sites. Researchers analysed the accumulation of STX-group toxins using a LC with a derivatisation post column (LC-PCOX), while lipophilic toxins (OA-group, azapiracids, pectenotoxins and yessotoxins) were analysed using LC-MS/MS with electrospray ionisation (+/-) in visceral (hepatopancreas) and non-visceral tissues (mantle, adductor muscle, gills and foot). Levels of STX-group and OA-group toxins varied among individuals from the same site. Among all tissue samples, the highest concentrations of STX-group toxins were noted in the hepatopancreas in V. antiqua (95 ± 0.1 μg STX-eq 100 g(-1)), T. dombeii (148 ± 1.4 μg STX-eq 100 g(-1)) and G. solida (3232 ± 5.2 μg STX-eq 100 g(-1); p mantle > adductor muscle for the STX-group toxins and foot > digestive gland for the OA-group toxins. These results gave a better understanding of the variability and compartmentalisation of STX-group and OA-group toxins in different bivalve and gastropod species from the south of Chile, and the analyses determined that tissues could play an important role in the biotransformation of STX-group toxins and the retention of OA-group toxins. PMID:25769036

  12. Effects of waste activated sludge and surfactant addition on primary sludge hydrolysis and short-chain fatty acids accumulation.

    Ji, Zhouying; Chen, Guanlan; Chen, Yinguang

    2010-05-01

    This paper focused on the effects of waste activated sludge (WAS) and surfactant sodium dodecylbenzene sulfonate (SDBS) addition on primary sludge (PS) hydrolysis and short-chain fatty acids (SCFA) accumulation in fermentation. The results showed that sludge hydrolysis, SCFA accumulation, NH(4)(+)-N and PO(4)(3-)-P release, and volatile suspended solids (VSS) reduction were increased by WAS addition to PS, which were further increased by the addition of SDBS to the mixture of PS and WAS. Acetic, propionic and valeric acids were the top three SCFA in all experiments. Also, the fermentation liquids of PS, PS+WAS, and PS+WAS+SDBS were added, respectively, to municipal wastewater to examine their effects on biological municipal wastewater treatment, and the enhancement of both wastewater nitrogen and phosphorus removals was observed compared with no fermentation liquid addition. PMID:20096564

  13. Effects of LaCl3 on photosynthesis and the accumulation of tanshinones and salvianolic acids in Salvia miltiorrhiza seedlings

    ZHOU Jie; GUO Lanping; ZHANG Ji; ZHOU Shufeng; YANG Guang; ZHAO Manxi; HUANG Luqi

    2011-01-01

    The effects of LaCl3 on the growth, photosynthetic gas-exchange characteristics, chlorophyll fluorescence, and the accumulation of tanshinones and salvianolic acids in Salvia miltiorrhiza seedlings were investigated. The results showed that the increase in photosynthesis induced by LaCl3 might be attributed to the enhanced stomatal conductance of the leaves and the increased level of the photochemical efficiency of PS Ⅱ. The accumulation of tanshinone IIA and cryptotanshinone was markedly increased with the application of LaCl3 at 20 and 60mg/L, while tanshinone I was only slightly increased. The content of salvianolic acid B was, however, decreased with the treatment of LaCl3at 200 mg/L.

  14. Naturally evolved enhanced Cd tolerance of Dianthus carthusianorum L. is not related to accumulation of thiol peptides and organic acids.

    Wójcik, Małgorzata; Dresler, Sławomir; Plak, Andrzej; Tukiendorf, Anna

    2015-05-01

    Two contrasting ecotypes of Dianthus carthusianorum L., metallicolous (M) and nonmetallicolous (NM), were cultivated in hydroponics at 0-50 μM Cd for 14 days to compare their Cd accumulation, sensitivity and tolerance mechanisms. While both ecotypes contained similar concentrations of Cd in the shoots and roots, the M ecotype was more Cd-tolerant (as measured by fresh weight production and root and leaf viability). Both ecotypes accumulated phytochelatins (PCs) in response to Cd with a higher amount thereof found in the NM ecotype. Concentrations of PCs remained unchanged with increasing Cd concentrations in the root tissues, but their content in the shoots increased. The addition of L-buthionine-sulfoximine (BSO) diminished glutathione (GSH) accumulation and arrested PC production, which increased the sensitivity to Cd of the NM, but not M ecotype. Organic acids (malate and citrate) as well as proline accumulation did not change significantly after Cd exposition and was at the same level in both ecotypes. The enhanced Cd tolerance of the M ecotype of D. carthusianorum cannot be explained in terms of restricted Cd uptake and differential production of PCs, organic acids or proline; some other mechanisms must be involved in its adaptation to the high Cd content in the environment. PMID:25510617

  15. Cd and Ni transport and accumulation in the halophyte Sesuvium portulacastrum: implication of organic acids in these processes.

    Mnasri, Mejda; Ghabriche, Rim; Fourati, Emna; Zaier, Hanen; Sabally, Kebba; Barrington, Suzelle; Lutts, Stanley; Abdelly, Chedly; Ghnaya, Tahar

    2015-01-01

    The implication of organic acids in Cd and Ni translocation was studied in the halophyte species Sesuvium portulacastrum. Citric, fumaric, malic, and ascorbic acids were separated and quantified by HPLC technique in shoots, roots and xylem saps of plants grown on nutrient solutions added with 50 μM Cd, 100 μM Ni and the combination of 50 μM Cd + 100 μM Ni. Results showed that Cd had no significant impact on biomass production while Ni and the combination of both metals drastically affected plant development. Cadmium and Ni concentrations in tissues and xylem sap were higher in plants subjected to individual metal application than those subjected to the combined effect of Cd and Ni suggesting a possible competition between these metals for absorption. Both metals applied separately or in combination induced an increase in citrate concentration in shoots and xylem sap but a decrease of this concentration in the roots. However, a minor relationship was observed between metal application and fumaric, malic, and ascorbic acids. Both observations suggest the implication of citric acid in Cd, Ni translocation and shoot accumulation in S. portulacastrum. The relatively high accumulation of citric acid in xylem sap and shoot of S. portulacastrum could be involved in metal chelation and thus contributes to heavy metal tolerance in this species. PMID:25821455

  16. Cd and Ni transport and accumulation in the halophyte Sesuvium portulacastrum: implication of organic acids in these processes

    Tahar eGhnaya

    2015-03-01

    Full Text Available The implication of organic acids in Cd and Ni translocation was studied in the halophyte species Sesuvium portulacastrum. Citric, fumaric, malic and ascorbic acids were separated and quantified by HPLC technique in shoots, roots and xylem saps of plants grown on nutrient solutions added with 50 µM Cd, 100 µM Ni and the combination of 50 µM Cd + 100 µM Ni. Results showed that Cd had no significant impact on biomass production while Ni and the combination of both metals drastically affected plant development. Cadmium and Ni concentrations in tissues and xylem sap were higher in plants individually exposed to heavy metal application than in those subjected to the combined treatment Cd + Ni, suggesting a possible competition between these metals for absorption. Both metals applied separately or in combination induced an increase in citrate concentration in shoots and xylem sap but a decrease of this concentration in the roots. However a minor relationship was observed between metal application and fumaric, malic and ascorbic acids. Both observations suggest the implication of citric acid in Cd, Ni translocation and shoot accumulation in S. portulacastrum. The relatively high accumulation of citric acid in xylem sap and shoot of S. portulacastrum could be involved in metal chelation and thus contributes to heavy metal tolerance in this species.

  17. Fungal biotransformation of chlorogenic and caffeic acids by Fusarium graminearum: New insights in the contribution of phenolic acids to resistance to deoxynivalenol accumulation in cereals.

    Gauthier, Léa; Bonnin-Verdal, Marie-Noelle; Marchegay, Gisèle; Pinson-Gadais, Laetitia; Ducos, Christine; Richard-Forget, Florence; Atanasova-Penichon, Vessela

    2016-03-16

    Fusarium Head Blight and Gibberella Ear Rot, mainly caused by the fungi Fusarium graminearum and Fusarium culmorum, are two of the most devastating diseases of small-grain cereals and maize. In addition to yield loss, these diseases frequently result in contamination of kernels with toxic type B trichothecenes. The potential involvement of chlorogenic acid in cereal resistance to Fusarium Head Blight and Gibberella Ear Rot and to trichothecene accumulation was the focus of this study. The effects of chlorogenic acid and one of its hydrolyzed products, caffeic acid, on fungal growth and type B trichothecenes biosynthesis were studied using concentrations close to physiological amounts quantified in kernels and a set of F. graminearum and F. culmorum strains. Both chlorogenic and caffeic acids negatively impact fungal growth and mycotoxin production, with caffeic acid being significantly more toxic. Inhibitory efficiencies of both phenolic acids were strain-dependent. To further investigate the antifungal and anti "mycotoxin" effect of chlorogenic and caffeic acids, the metabolic fate of these two phenolic acids was characterized in supplemented F. graminearum broths. For the first time, our results demonstrated the ability of F. graminearum to degrade chlorogenic acid into caffeic, hydroxychlorogenic and protocatechuic acids and caffeic acid into protocatechuic and hydroxycaffeic acids. Some of these metabolic products can contribute to the inhibitory efficiency of chlorogenic acid that, therefore, can be compared as a "pro-drug". As a whole, our data corroborate the contribution of chlorogenic acid to the chemical defense that cereals employ to counteract F. graminearum and its production of mycotoxins. PMID:26812586

  18. Path analysis suggests phytoene accumulation is the key step limiting the carotenoid pathway in white carrot roots

    Carlos Antonio Fernandes Santos

    2005-01-01

    Full Text Available Two F2 carrot (Daucus carota L. populations (orange rooted Brasilia x very dark orange rooted High Carotene Mass - HCM cross and the dark orange rooted cultivated variety B493 x white rooted wild carrot Queen Anne's Lace - QAL cross with very unrelated genetic backgrounds were used to investigate intrinsic factors limiting carotenoid accumulation in carrots by applying phenotypic correlation and path analysis to study the relationships between major root carotenes, root color and several other morphological traits. Most of the correlations between traits were close and agreed in sign between the two populations. Root weight had a moderate to highly significant positive correlation with leaf length, root length and top and middle root diameter. Although phenotypic correlations failed to identify the order of the substrates and products in the carotenoid pathway the correct order of substrates and products (phytoene -> zeta-carotene -> lycopene was identified in the causal diagram of beta-carotene for the Brasilia x HCM population. Path analysis of beta-carotene synthesis in the B493 x QAL population suggested that selection for root carotenes had little effect on plant morphological traits. Causal model of beta-carotene and lycopene in the B493 x QAL population suggested that phytoene synthesis is the key step limiting the carotenoid pathway in white carrots. Path analysis, first presented by Sewall Wright to study quantitative traits, appears to be a powerful statistical approach for the identification of key compounds in complex pathways.

  19. Do acid volatile sulfides (AVS) influence the accumulation of sediment-bound metals to benthic invertebrates under natural field conditions?

    De Jonge, Maarten; Dreesen, Freja; De Paepe, Josefina; Blust, Ronny; Bervoets, Lieven

    2009-06-15

    The present study evaluates the influence of acid volatile sulfides (AVS) on accumulation of sediment-bound metals in benthic invertebrates under natural field conditions. Natural sediments, pore water, surface water, and two species of widespread benthic invertebrates (Chironomus gr. thummi and Tubifex tubifex) were collected from 17 historical polluted Flemish lowland rivers and measured for metal concentrations. Different sediment characteristics were determined (AVS, organic matter, clay content) and multiple regression was used to study their relationship with accumulated metals in the invertebrates. Physical and chemical analysis of the field samples indicated low metal concentrations in the water and pore water, but very high metal concentrations in the sediment and the invertebrates, especially for Pb (5.99 micromol/ g). In general, metal accumulation in chironomids and tubificid worms was most strongly correlated with total metal concentrations in the sediment and sediment metal concentrations normalized for organic matter and clay content. Following the results of the linear regression model, AVS did not turn out to be a significant variable in describing variation in metal accumulation. Our study clearly demonstrates that, in addition to the results gained from experiments under lab conditions, benthic invertebrates can accumulate metals from unspiked field sediments even when there's an excess of AVS. PMID:19603670

  20. Point mutation of the xylose reductase (XR) gene reduces xylitol accumulation and increases citric acid production in Aspergillus carbonarius

    Weyda, István; Lübeck, Mette; Ahring, Birgitte K; Peter S. Lübeck

    2014-01-01

    Aspergillus carbonarius accumulates xylitol when it grows on d-xylose. In fungi, d-xylose is reduced to xylitol by the NAD(P)H-dependent xylose reductase (XR). Xylitol is then further oxidized by the NAD+-dependent xylitol dehydrogenase (XDH). The cofactor impairment between the XR and XDH can lead to the accumulation of xylitol under oxygen-limiting conditions. Most of the XRs are NADPH dependent and contain a conserved Ile-Pro-Lys-Ser motif. The only known naturally occurring NADH-dependent...

  1. Regulation of erucic acid accumulation in oilseed rape (Brassica napus L.). Effects of temperature and abscisic acid.

    Wilmer, J.A.

    1997-01-01

    Vegetable oils are an important commodity world-wide with an annual production of about 70 million tonnes. Oilseed rape is one of the four major crops, providing about 10% of the total production. Quality of vegetable oils is determined by the fatty acid composition of the triacylglycerols (TAG) that constitute such oils. These fatty acids comprise a range of chain lengths and desaturated and oxidised residues. A small group of fatty acids dominates the edible oils which are the predominant p...

  2. Genome-scale metabolic modeling and in silico analysis of lipid accumulating yeast Candida tropicalis for dicarboxylic acid production.

    Mishra, Pranjul; Park, Gyu-Yeon; Lakshmanan, Meiyappan; Lee, Hee-Seok; Lee, Hongweon; Chang, Matthew Wook; Ching, Chi Bun; Ahn, Jungoh; Lee, Dong-Yup

    2016-09-01

    Recently, the bio-production of α,ω-dicarboxylic acids (DCAs) has gained significant attention, which potentially leads to the replacement of the conventional petroleum-based products. In this regard, the lipid accumulating yeast Candida tropicalis, has been recognized as a promising microbial host for DCA biosynthesis: it possess the unique ω-oxidation pathway where the terminal carbon of α-fatty acids is oxidized to form DCAs with varying chain lengths. However, despite such industrial importance, its cellular physiology and lipid accumulation capability remain largely uncharacterized. Thus, it is imperative to better understand the metabolic behavior of this lipogenic yeast, which could be achieved by a systems biological approach. To this end, herein, we reconstructed the genome-scale metabolic model of C. tropicalis, iCT646, accounting for 646 unique genes, 945 metabolic reactions, and 712 metabolites. Initially, the comparative network analysis of iCT646 with other yeasts revealed several distinctive metabolic reactions, mainly within the amino acid and lipid metabolism including the ω-oxidation pathway. Constraints-based flux analysis was, then, employed to predict the in silico growth rates of C. tropicalis which are highly consistent with the cellular phenotype observed in glucose and xylose minimal media chemostat cultures. Subsequently, the lipid accumulation capability of C. tropicalis was explored in comparison with Saccharomyces cerevisiae, indicating that the formation of "citrate pyruvate cycle" is essential to the lipid accumulation in oleaginous yeasts. The in silico flux analysis also highlighted the enhanced ability of pentose phosphate pathway as NADPH source rather than malic enzyme during lipogenesis. Finally, iCT646 was successfully utilized to highlight the key directions of C. tropicalis strain design for the whole cell biotransformation application to produce long-chain DCAs from alkanes. Biotechnol. Bioeng. 2016;113: 1993-2004.

  3. Acidification, heavy metal mobility and nutrient accumulation in the soil-plant system of a revegetated acid mine wasteland.

    Yang, Sheng-Xiang; Liao, Bin; Li, Jin-tian; Guo, Tao; Shu, Wen-Sheng

    2010-08-01

    A revegetation program was established at an extreme acidic and metal-toxic pyrite/copper mine wasteland in Guangdong Province, PR China using a combination of four native grass species and one non-native woody species. It was continued and monitored for 2 y. The emphasis was on acidification, metal mobility and nutrient accumulation in the soil-plant system. Our results showed the following: (i) the acid-forming potential of the mine soils decreased steadily with time, which might be due to plant root-induced changes inhibiting the oxidization of sulphide minerals; (ii) heavy metal extractability (diethylene-triamine-pentaacetic acid-extractable Pb and Zn) in the soils increased with time despite an increase in soil pH, which might be attributed to soil disturbance and plant rhizospheric processes, as well as a consequence of the enhanced metal accumulation in plants over time; and (iii) the vegetation cover increased rapidly with time, and plant development accelerated the accumulation of major nutrients (organic matter, total and ammonium-N, and available P and K). The 2-y field experiment demonstrates that direct seeding/planting of native plant species in combination with lime and manure amelioration is a practical approach to the initial establishment of a self-sustaining vegetation cover on this metalliferous and sulphide-bearing mine wasteland. However, heavy metal accumulation in the soil-plant system should be of great concern, and long-term monitoring of ecological risk must be an integral part of such a restoration scheme. PMID:20580409

  4. Selection for low erucic acid and genetic mapping of loci affecting the accumulation of very long-chain fatty acids in meadowfoam seed storage lipids.

    Gandhi, S D; Kishore, V K; Crane, J M; Slabaugh, M B; Knapp, S J

    2009-06-01

    Erucic acid (22:1(13)) has been identified as an anti-nutritional compound in meadowfoam (Limnanthes alba) and other oilseeds in the Brassicales, a classification which has necessitated the development of low erucic acid cultivars for human consumption. The erucic acid concentrations of meadowfoam wild types (8%-24%) surpass industry standards for human consumption (acid lines and identify loci affecting the accumulation of 22:1(13) and other very long-chain fatty acids (VLCFAs) in meadowfoam seed storage lipids. LE76, a low erucic acid line, was developed by 3 cycles of selection in an ethyl methanesulfonate-treated wildtype population. LE76 produced 3% 22:1(13), threefold less than the M0 population. Wildtype x LE76 F2 populations produced continuous, approximately normal erucic and dienoic acid distributions. Loss-of-function mutations apparently did not segregate and individuals with low 22:1(13) concentrations (acid F2 progeny. Composite interval mapping identified 3 moderately large-effect erucic acid QTL. The low erucic acid parent transmitted favorable alleles for 2 of 3 QTL, suggesting low erucic acid cultivars can be developed by combining favorable alleles transmitted by wildtype and low erucic acid parents. PMID:19483773

  5. The levels of heavy metals in water and all aquatic in Ismailia canal, (Egypt) compared with the international permissible limits and accumulative studies for these metals in biota

    The concentration of Pb, Cd, Cu, Zu, Ni, Fe and Mn were determined in water, and in different organs of fishes, bivalves, snails and plants in Ismailia canal, Egypt. Moreover, accumulation of the investigated heavy metals by aquatic biota in Ismailia canal and the concentration factor values for this accumulation were calculated to qualify the degree of pollution and compare these levels with the international permissible limits. Results showed that Pb, Cd, Cu and Zn were exceeded the permissible limits especially in the industrial area of Abu- Zaabal, Kalubia governorate. The relative order of heavy metal levels in the canal water was: Fe>Mn>Pb>Zn>Ni>Cd>Cu.Accumulation of heavy metals by the aquatic biota was determined. The accumulation of heavy metals by common snails, namely physa acuta and biomphalaria alexandrina and the bivalve oyster Caelatura (caelatura) companyoi was found mainly in the edible parts (soft parts), whereas, the accumulation by their shells, which are mainly formed of calcium carbonate was via adsorption and surface complexation, since all the accumulated heavy metals were released by adding 0.1 M HCl for few minutes . Moreover, accumulation of heavy metals by common plants namely water hyacinth plant (Eichhornia crassipes) and freshwater weeds were determined. It was found that the accumulation of heavy metals was higher in roots than in leaves. On the other hand, the accumulation of heavy metals by common fish namely, Oreochromis niloticus (Nile Tilapia) was measured in its organs : muscles, liver, gills and gonads. It was found that there is variation of distribution of heavy metals among fish organs. Since the high accumulation of heavy metals among the investigated biota, they can be used as biological indicator for pollution of heavy metals in aquatic ecosystem . The average values and standard deviation for all measurements were determined. Data obtained were compared with the permissible concentrations of the environmental protection

  6. Accumulation of Phenolic Compounds and Expression Profiles of Phenolic Acid Biosynthesis-Related Genes in Developing Grains of White, Purple, and Red Wheat

    Ma, Dongyun; Li, Yaoguang; Zhang, Jian; Wang, Chenyang; Qin, Haixia; Ding, Huina; Xie, Yingxin; Guo, Tiancai

    2016-01-01

    Polyphenols in whole grain wheat have potential health benefits, but little is known about the expression patterns of phenolic acid biosynthesis genes and the accumulation of phenolic acid compounds in different-colored wheat grains. We found that purple wheat varieties had the highest total phenolic content (TPC) and antioxidant activity. Among phenolic acid compounds, bound ferulic acid, vanillic, and caffeic acid levels were significantly higher in purple wheat than in white and red wheat,...

  7. Ultraviolet light and ozone stimulate accumulation of salicylic acid, pathogenesis-related proteins and virus resistance in tobacco

    In tobacco (Nicotiana tabacum L. cv. Xanthinc), salicylic acid (SA) levels increase in leaves inoculated by necrotizing pathogens and in healthy leaves located above the inoculated site. Systemic SA increase may trigger disease resistance and synthesis of pathogenesis-related proteins (PR proteins). Here we report that ultraviolet (UV)-C light or ozone induced biochemical responses similar to those induced by necrotizing pathogens. Exposure of leaves to UV-C light or ozone resulted in a transient ninefold increase in SA compared to controls. In addition, in UV-light-irradiated plants, SA increased nearly fourfold to 0.77 μg·g−1 fresh weight in leaves that were shielded from UV light. Increased SA levels were accompanied by accumulation of an SA conjugate and by an increase in the activity of benzoic acid 2-hydroxylase which catalyzes SA biosynthesis. In irradiated and in unirradiated leaves of plants treated with UV light, as well as in plants fumigated with ozone, PR proteins 1a and 1b accumulated. This was paralleled by the appearance of induced resistance to a subsequent challenge with tobacco mosaic virus. The results suggest that UV light, ozone fumigation and tobacco mosaic virus can activate a common signal-transduction pathway that leads to SA and PR-protein accumulation and increased disease resistance. (author)

  8. Some things get better with age: differences in salicylic acid accumulation and defense signaling in young and mature Arabidopsis

    Philip eCarella

    2015-01-01

    Full Text Available In Arabidopsis, much of what we know about the phytohormone salicylic acid (SA and its role in plant defense comes from experiments using young plants. We are interested in understanding why young plants are susceptible to virulent strains of Pseudomonas syringae, while mature plants exhibit a robust defense response known as Age-Related Resistance (ARR. SA-mediated signaling is important for defense in young plants, however, ARR occurs independently of the defense regulators NPR1 and WHY1. Furthermore, intercellular SA accumulation is an important component of ARR, and intercellular washing fluids from ARR-competent plants exhibit antibacterial activity, suggesting that SA acts as an antimicrobial agent in the intercellular space. Young plants accumulate both intracellular and intercellular SA during PAMP- and Effector-Triggered Immunity, however, virulent P. syringae promotes susceptibility by suppressing SA accumulation using the phytotoxin coronatine. Here we outline the hypothesis that mature, ARR-competent Arabidopsis alleviates coronatine-mediated suppression of SA accumulation. We also explore the role of SA in other mature-plant processes such as flowering and senescence, and discuss their potential impact on ARR.

  9. Deleted in Breast Cancer 1 Limits Adipose Tissue Fat Accumulation and Plays a Key Role in the Development of Metabolic Syndrome Phenotype

    Escande, Carlos; Nin, Veronica; Pirtskhalava, Tamar; Chini, Claudia C. S.; Tchkonia, Tamar; Kirkland, James L.; Chini, Eduardo N.

    2015-01-01

    Obesity is often regarded as the primary cause of metabolic syndrome. However, many lines of evidence suggest that obesity may develop as a protective mechanism against tissue damage during caloric surplus and that it is only when the maximum fat accumulation capacity is reached and fatty acid spill

  10. The Citrus transcription factor, CitERF13, regulates citric acid accumulation via a protein-protein interaction with the vacuolar proton pump, CitVHA-c4.

    Li, Shao-jia; Yin, Xue-ren; Xie, Xiu-lan; Allan, Andrew C; Ge, Hang; Shen, Shu-ling; Chen, Kun-song

    2016-01-01

    Organic acids are essential to fruit flavor. The vacuolar H(+) transporting adenosine triphosphatase (V-ATPase) plays an important role in organic acid transport and accumulation. However, less is known of V-ATPase interacting proteins and their relationship with organic acid accumulation. The relationship between V-ATPase and citric acid was investigated, using the citrus tangerine varieties 'Ordinary Ponkan (OPK)' and an early maturing mutant 'Zaoshu Ponkan (ZPK)'. Five V-ATPase genes (CitVHA) were predicted as important to citric acid accumulation. Among the genes, CitVHA-c4 was observed, using a yeast two-hybrid screen, to interact at the protein level with an ethylene response factor, CitERF13. This was verified using bimolecular fluorescence complementation assays. A similar interaction was also observed between Arabidopsis AtERF017 (a CitERF13 homolog) and AtVHA-c4 (a CitVHA-c4 homolog). A synergistic effect on citric acid levels was observed between V-ATPase proteins and interacting ERFs when analyzed using transient over-expression in tobacco and Arabidopsis mutants. Furthermore, the transcript abundance of CitERF13 was concomitant with CitVHA-c4. CitERF13 or AtERF017 over-expression leads to significant citric acid accumulation. This accumulation was abolished in an AtVHA-c4 mutant background. ERF-VHA interactions appear to be involved in citric acid accumulation, which was observed in both citrus and Arabidopsis. PMID:26837571

  11. Methyl Jasmonate and Salicylic Acid Induced Oxidative Stress and Accumulation of Phenolics in Panax ginseng Bioreactor Root Suspension Cultures

    Kee-Yoeup Paek

    2007-03-01

    Full Text Available To investigate the enzyme variations responsible for the synthesis of phenolics, 40 day-old adventitious roots of Panax ginseng were treated with 200 μM methyl jasmonate (MJ or salicylic acid (SA in a 5 L bioreactor suspension culture (working volume 4 L. Both treatments caused an increase in the carbonyl and hydrogen peroxide (H2O2 contents, although the levels were lower in SA treated roots. Total phenolic, flavonoid, ascorbic acid, non-protein thiol (NPSH and cysteine contents and 1,1-diphenyl-2-picrylhydrazyl (DPPH radical reducing activity were increased by MJ and SA. Fresh weight (FW and dry weight (DW decreased significantly after 9 days of exposure to SA and MJ. The highest total phenolics (62%, DPPH activity (40%, flavonoids (88%, ascorbic acid (55%, NPSH (33%, and cysteine (62% contents compared to control were obtained after 9 days in SA treated roots. The activities of glucose 6-phosphate dehydrogenase, phenylalanine ammonia lyase, substrate specific peroxidases (caffeic acid peroxidase, quercetin peroxidase and ferulic acid peroxidase were higher in MJ treated roots than the SA treated ones. Increased shikimate dehydrogenase, chlorogenic acid peroxidase and β-glucosidase activities and proline content were observed in SA treated roots than in MJ ones. Cinnamyl alcohol dehydrogenase activity remained unaffected by both MJ and SA. These results strongly indicate that MJ and SA induce the accumulation of phenolic compounds in ginseng root by altering the phenolic synthesis enzymes.

  12. Stearoyl-CoA desaturase-1 (SCD1 augments saturated fatty acid-induced lipid accumulation and inhibits apoptosis in cardiac myocytes.

    Hiroki Matsui

    Full Text Available Mismatch between the uptake and utilization of long-chain fatty acids in the myocardium leads to abnormally high intracellular fatty acid concentration, which ultimately induces myocardial dysfunction. Stearoyl-Coenzyme A desaturase-1 (SCD1 is a rate-limiting enzyme that converts saturated fatty acids (SFAs to monounsaturated fatty acids. Previous studies have shown that SCD1-deficinent mice are protected from insulin resistance and diet-induced obesity; however, the role of SCD1 in the heart remains to be determined. We examined the expression of SCD1 in obese rat hearts induced by a sucrose-rich diet for 3 months. We also examined the effect of SCD1 on myocardial energy metabolism and apoptotic cell death in neonatal rat cardiac myocytes in the presence of SFAs. Here we showed that the expression of SCD1 increases 3.6-fold without measurable change in the expression of lipogenic genes in the heart of rats fed a high-sucrose diet. Forced SCD1 expression augmented palmitic acid-induced lipid accumulation, but attenuated excess fatty acid oxidation and restored reduced glucose oxidation. Of importance, SCD1 substantially inhibited SFA-induced caspase 3 activation, ceramide synthesis, diacylglycerol synthesis, apoptotic cell death, and mitochondrial reactive oxygen species (ROS generation. Experiments using SCD1 siRNA confirmed these observations. Furthermore, we showed that exposure of cardiac myocytes to glucose and insulin induced SCD1 expression. Our results indicate that SCD1 is highly regulated by a metabolic syndrome component in the heart, and such induction of SCD1 serves to alleviate SFA-induced adverse fatty acid catabolism, and eventually to prevent SFAs-induced apoptosis.

  13. SFH2 regulates fatty acid synthase activity in the yeast Saccharomyces cerevisiae and is critical to prevent saturated fatty acid accumulation in response to haem and oleic acid depletion

    Desfougères, Thomas; Ferreira, Thierry; Bergès, Thierry; Régnacq, Matthieu

    2007-01-01

    Abstract The yeast Saccharomyces cerevisiae is a facultative anaerobic organism. In anaerobiosis, sustained growth relies on the presence of exogenously supplied unsaturated fatty acids and ergosterol that yeast is unable to synthesize in the absence of oxygen or upon haem depletion. In the absence of exogenous supplementation with unsaturated fatty acid, a net accumulation of saturated fatty acid (SFA) is observed that induces significant modification of phospholipid profile [1]. ...

  14. Metabolism of L-malic acid accumulation in Aspergillus flavus%黄曲霉积累L-苹果酸代谢机制初探

    郝夕祥; 刘建军; 赵祥颖; 田延军; 张家祥

    2011-01-01

    L-malic acid is a member of tricarboxylic acid cycle (TCA cycle) in organism, which has widespread applications in food, medical, daily chemical industry, etc. The paper preliminary introduced the metabolic mechanism of L-malic acid in Aspergillus flavus from the aspects of limiting oxygen fermentation, the addition of calcium carbonate, the inhibitor of enzyme in the TCA cycle, glyoxylate cycle and so on. It was concluded that CO2 fixing pathway was the main route accumulating L-malic acid.%L-苹果酸是生物体内三羧酸循环的成员之一,在食品、医药、日用化工等部门具有广泛的用途.文中从限氧发酵、碳酸钙的添加量、乙醛酸循环和TCA循环相应酶的抑制剂几个方面初步探讨黄曲霉积累L-苹果酸的代谢机制,得出CO2固定途径是积累L-苹果酸的主要途径.

  15. Environmental Risk Limits for Ethylene Diamine Tetra Acetic acid (EDTA)

    Kalf DF; Hoop MAGT van den; Rila JP; Posthuma C; Traas TP; SEC

    2003-01-01

    In this report maximum permissible concentration (MPC) and negligible concentration (NC) in water are derived for Ethylene Diamine Tetra Acetic acid (EDTA; CAS No. 64-02-8, EINECS No. 200-573-9), based on the EU risk assessment report for this compound. The Maximum Permissible Concentration (MPC) for the water compartment is 2.2 mg/l, and the Negligible Concentration (NC) is 0.022 mg/l. Calculation of MPCs for sediment or soil is not possible due to complex speciation of EDTA.

  16. Jasmonic acid is involved in the signaling pathway for fungal endophyte-induced volatile oil accumulation of Atractylodes lancea plantlets

    Ren Cheng-Gang

    2012-08-01

    Full Text Available Abstract Background Jasmonic acid (JA is a well-characterized signaling molecule in plant defense responses. However, its relationships with other signal molecules in secondary metabolite production induced by endophytic fungus are largely unknown. Atractylodes lancea (Asteraceae is a traditional Chinese medicinal plant that produces antimicrobial volatiles oils. We incubated plantlets of A. lancea with the fungus Gilmaniella sp. AL12. to research how JA interacted with other signal molecules in volatile oil production. Results Fungal inoculation increased JA generation and volatile oil accumulation. To investigate whether JA is required for volatile oil production, plantlets were treated with JA inhibitors ibuprofen (IBU and nordihydroguaiaretic acid. The inhibitors suppressed both JA and volatile oil production, but fungal inoculation could still induce volatile oils. Plantlets were further treated with the nitric oxide (NO-specific scavenger 2-(4-carboxyphenyl-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide potassium salt (cPTIO, the H2O2 inhibitors diphenylene iodonium (DPI and catalase (CAT, and the salicylic acid (SA biosynthesis inhibitors paclobutrazol and 2-aminoindan-2-phosphonic acid. With fungal inoculation, IBU did not inhibit NO production, and JA generation was significantly suppressed by cPTIO, showing that JA may act as a downstream signal of the NO pathway. Exogenous H2O2 could reverse the inhibitory effects of cPTIO on JA generation, indicating that NO mediates JA induction by the fungus through H2O2-dependent pathways. With fungal inoculation, the H2O2 scavenger DPI/CAT could inhibit JA generation, but IBU could not inhibit H2O2 production, implying that H2O2 directly mediated JA generation. Finally, JA generation was enhanced when SA production was suppressed, and vice versa. Conclusions Jasmonic acid acts as a downstream signaling molecule in NO- and H2O2-mediated volatile oil accumulation induced by endophytic fungus and has

  17. Fatty acid transport protein-2 inhibitor Grassofermata/CB5 protects cells against lipid accumulation and toxicity

    The inhibition of the fatty acid uptake into non-adipose tissues provides an attractive target for prevention of lipotoxicity leading to obesity-associated non-alcoholic fatty liver disease and type 2 diabetes. Fatty acid transport proteins (FATPs) are bifunctional proteins involved in the uptake and activation of fatty acids by esterification with coenzyme A. Here we characterize Grassofermata/CB5, previously identified as a fatty acid uptake inhibitor directed against HsFATP2. The compound was effective in inhibiting the uptake of fatty acids in the low micro-molar range (IC50 8–11 μM) and prevented palmitate-mediated lipid accumulation and cell death in cell lines that are models for intestines, liver, muscle and pancreas. In adipocytes, uptake inhibition was less effective (IC50 58 μM). Inhibition was specific for long chain fatty acids and was ineffective toward medium chain fatty acids, which are transported by diffusion. Kinetic analysis of Grassofermata-dependent FA transport inhibition verified a non-competitive mechanism. By comparison with Grassofermata, several atypical antipsychotic drugs previously implicated as inhibitors of FA uptake were ineffectual. In mice Grassofermata decreased absorption of 13C-oleate demonstrating its potential as a therapeutic agent. - Highlights: • Grassofermata is a small compound inhibitor of FATP2. • Uptake inhibition is specific for long chain fatty acids. • Uptake kinetics shows low specificity for adipocytes compared to other cell types. • Inhibition is by a non-competitive mechanism. • Atypical antipsychotics do not inhibit FA uptake by comparison with Grassofermata

  18. Fatty acid transport protein-2 inhibitor Grassofermata/CB5 protects cells against lipid accumulation and toxicity

    Saini, Nipun; Black, Paul N.; Montefusco, David; DiRusso, Concetta C., E-mail: cdirusso2@unl.edu

    2015-09-25

    The inhibition of the fatty acid uptake into non-adipose tissues provides an attractive target for prevention of lipotoxicity leading to obesity-associated non-alcoholic fatty liver disease and type 2 diabetes. Fatty acid transport proteins (FATPs) are bifunctional proteins involved in the uptake and activation of fatty acids by esterification with coenzyme A. Here we characterize Grassofermata/CB5, previously identified as a fatty acid uptake inhibitor directed against HsFATP2. The compound was effective in inhibiting the uptake of fatty acids in the low micro-molar range (IC{sub 50} 8–11 μM) and prevented palmitate-mediated lipid accumulation and cell death in cell lines that are models for intestines, liver, muscle and pancreas. In adipocytes, uptake inhibition was less effective (IC{sub 50} 58 μM). Inhibition was specific for long chain fatty acids and was ineffective toward medium chain fatty acids, which are transported by diffusion. Kinetic analysis of Grassofermata-dependent FA transport inhibition verified a non-competitive mechanism. By comparison with Grassofermata, several atypical antipsychotic drugs previously implicated as inhibitors of FA uptake were ineffectual. In mice Grassofermata decreased absorption of {sup 13}C-oleate demonstrating its potential as a therapeutic agent. - Highlights: • Grassofermata is a small compound inhibitor of FATP2. • Uptake inhibition is specific for long chain fatty acids. • Uptake kinetics shows low specificity for adipocytes compared to other cell types. • Inhibition is by a non-competitive mechanism. • Atypical antipsychotics do not inhibit FA uptake by comparison with Grassofermata.

  19. Improved detection of coastal acid sulfate soil hotspots through biomonitoring of metal(loid) accumulation in water lilies (Nymphaea capensis).

    Stroud, Jacqueline L; Collins, Richard N

    2014-07-15

    Anthropogenically disturbed coastal acid sulfate soils along the east coast of Australia, and worldwide, periodically result in the discharge of acid waters containing high concentrations of metals. Identifying priority sites (hotspots) within a catchment for acid sulfate soil remediation activities typically involves long-term monitoring of drainwater chemistry, including the capture of data on unpredictable rain-induced groundwater discharge events. To improve upon this monitoring approach, this study investigated using the water lily (Nymphaea capensis) as a biomonitor of drainage waters to identify hotspots in three acid sulfate soil impacted catchments (83 km(2)) in north-eastern New South Wales, Australia. In one catchment where the location of hotspots was known, water lily lamina concentrations of a suite of metal(loid)s were significantly (pcatchment-scale water lily sampling program undertaken in catchments with unidentified hotspots revealed within catchment variation of plant metal concentrations up to 70-fold. High resolution maps produced from these results, therefore, provided strong evidence for the location of potential hotspots which were confirmed with measurements of drainwater chemistry during rain-induced groundwater discharge events. Median catchment lily accumulation was ca. 160 mg Al kg(-1) and 1,300 mg Fe kg(-1), with hotspots containing up to 6- and 10-fold higher Al and Fe concentrations. These findings suggest that biomonitoring with N. capensis can be an important tool to rapidly identify priority sites for remediation in acid sulfate soil impacted landscapes. PMID:24805963

  20. Synergistic Accumulative Effect of Salicylic Acid and Dibutyl Phthalate on Paclitaxel Production in Corylus avellana Cell Culture

    Rezaei, A.

    2013-02-01

    Full Text Available Suspension cell cultures of Corylus avellana were challenged with salicylic acid and its combined use with dibutyl phthalate solvent. Salicylic acid with concentrations of 12.5, 25 and 50 mg L–1 and 10% (v/v dibutyl phthalate were used and added on day 8 and 10 of subculture, respectively. The results showed that growth, viability and protein content of cells were decreased by the treatments, compared to control. In all treatments, hydrogen peroxide content and lipid peroxidation rate of cells increased, compared to those of the control cells. Activity of phenylalanine ammonia-lyase increased by salicylic acid and, dibutyl phthalate exaggerated effect of salicylic acid. While flavonoids content decreased by the treatments, paclitaxel content increased significantly. The extracellular paclitaxel was more affected, compared to cell-associated paclitaxel and all treatments increased paclitaxel release and specific yield compared to that of the control. The most production of paclitaxel and specific yield of it were observed under effect of combined use of salicylic acid (50 mg L–1 and dibutyl phthalate, suggesting a synergistic accumulative effect.

  1. Identification and expression of a stearoyl-ACP desaturase gene responsible for oleic acid accumulation in Xanthoceras sorbifolia seeds.

    Zhao, Na; Zhang, Yuan; Li, Qiuqi; Li, Rufang; Xia, Xinli; Qin, Xiaowei; Guo, Huihong

    2015-02-01

    Xanthoceras sorbifolia Bunge is an oilseed tree that grows well on barren lands in dry climate. Its seeds contain a large amount of oil rich in oleic acid (18:1(Δ9)) and linoleic acid (18:2(Δ9, 12)). However, the molecular regulation of oil biosynthesis in X. sorbifolia seeds is poorly understood. Stearoyl-ACP desaturase (SAD, EC 1.14.99.6) is a plastid-localized soluble desaturase that catalyzes the conversion of stearic acid (18:0) to oleic acid, which plays a key role in determining the ratio of saturated to unsaturated fatty acids. In this study, a full-length cDNA of XsSAD was isolated from developing X. sorbifolia embryos. The XsSAD open reading frame had 1194-bp, encoding a polypeptide of 397 amino acids. XsSAD expression in Escherichia coli cells resulted in increased 18:1(Δ9) level, confirming the biological activity of the enzyme encoded by XsSAD. XsSAD expression in Arabidopsis ssi2 mutants partially restored the morphological phenotype and effectively increased the 18:1(Δ9) level. The levels of other unsaturated fatty acids synthesized with 18:1(Δ9) as the substrate also increased to some degree. XsSAD in X. sorbifolia had a much higher expression in embryos than in leaves and petals. XsSAD expression also correlated well with the oleic acid, unsaturated fatty acid, and total fatty acid levels in developing embryos. These data suggested that XsSAD determined the synthesis of oleic acid and contributed to the accumulation of unsaturated fatty acid and total oil in X. sorbifolia seeds. A preliminary tobacco rattle virus-based virus-induced gene silencing system established in X. sorbifolia can also be helpful for further analyzing the functions of XsSAD and other oil synthesis-related genes in woody plants. PMID:25528221

  2. The Citrus transcription factor, CitERF13, regulates citric acid accumulation via a protein-protein interaction with the vacuolar proton pump, CitVHA-c4

    Shao-jia Li; Xue-ren Yin; Xiu-lan Xie; Andrew C. Allan; Hang Ge; Shu-ling Shen; Kun-song Chen

    2016-01-01

    Organic acids are essential to fruit flavor. The vacuolar H+ transporting adenosine triphosphatase (V-ATPase) plays an important role in organic acid transport and accumulation. However, less is known of V-ATPase interacting proteins and their relationship with organic acid accumulation. The relationship between V-ATPase and citric acid was investigated, using the citrus tangerine varieties ‘Ordinary Ponkan (OPK)’ and an early maturing mutant ‘Zaoshu Ponkan (ZPK)’. Five V-ATPase genes (CitVHA...

  3. Regulation of erucic acid accumulation in oilseed rape (Brassica napus L.). Effects of temperature and abscisic acid.

    Wilmer, J.A.

    1997-01-01

    Vegetable oils are an important commodity world-wide with an annual production of about 70 million tonnes. Oilseed rape is one of the four major crops, providing about 10% of the total production. Quality of vegetable oils is determined by the fatty acid composition of the triacylglycerols (TAG) tha

  4. Graphene oxide induces plasma membrane damage, reactive oxygen species accumulation and fatty acid profiles change in Pichia pastoris.

    Zhang, Meng; Yu, Qilin; Liang, Chen; Liu, Zhe; Zhang, Biao; Li, Mingchun

    2016-10-01

    During the past couple of years, graphene nanomaterials were extremely popular among the scientists due to the promising properties in many aspects. Before the materials being well applied, we should first focus on their biosafety and toxicity. In this study, we investigated the toxicity of synthesized graphene oxide (GO) against the model industrial organism Pichia pastoris. We found that the synthesized GO showed dose-dependent toxicity to P. pastoris, through cell membrane damage and intracellular reactive oxygen species (ROS) accumulation. In response to these cell stresses, cells had normal unsaturated fatty acid (UFA) levels but increased contents of polyunsaturated fatty acid (PUFA) with up-regulation of UFA synthesis-related genes on the transcriptional level, which made it overcome the stress under GO attack. Two UFA defective strains (spt23Δ and fad12Δ) were used to demonstrate the results above. Hence, this study suggested a close connection between PUFAs and cell survival against GO. PMID:27376352

  5. Effects of Amino Acids Replacing Nitrate on Growth, Nitrate Accumulation, and Macroelement Concentrations in Pak-choi (Brassica chinensis L.)

    2007-01-01

    A hydroponic experiment was carried out to determine the influence of replacing 20% of nitrate-N in nutrient solutions with 20 individual amino acids on growth, nitrate accumulation, and concentrations of nitrogen (N), phosphorus (P), and potassium (K) in pak-choi (Brassica chinensis L.) shoots. When 20% of nitrate-N was replaced with arginine (Arg)compared to the full nitrate treatment, pak-choi shoot fresh and dry weights increased significantly (P ≤ 0.05), but when 20% of nitrate-N was replaced with alanine (Ala), valine (Val), leucine (Leu), isoleucine (Ile), proline (Pro), phenylalanine (Phe), methionine (Met), aspartic acid (Asp), glutamic acid (Glu), lysine (Lys), glycine (Gly), serine (Ser), threonine(Thr), cysteine (Cys), and tyrosine (Tyr), shoot fresh and dry weights decreased significantly (P ≤ 0.05). After replacing 20% of nitrate-N with asparagine (Asn) and glutamine (Gln), shoot fresh and dry weights were unaffected. Compared to the full nitrate treatment, amino acid replacement treatments, except for Cys, Gly, histidine (His), and Arg, significantly reduced (P ≤ 0.05) nitrate concentrations in plant shoots. Except for Cys, Leu, Pro, and Met, total N concentrations in plant tissues of the other amino acid treatments significantly increased (P ≤ 0.05). Amino acids also affected total P and K concentrations, but the effects differed depending on individual amino acids. To improve pak-choi shoot quality, Gln and Asn, due to their insignificant effects on pak-choi growth, their significant reduction in nitrate concentrations, and their increase in macroelement content in plants, may be used to partially replace nitrate-N.

  6. Limiting Current of Oxygen Reduction on Gas-Diffusion Electrodes for Phosphoric Acid Fuel Cells

    Li, Qingfeng; Gang, Xiao; Hjuler, Hans Aage;

    1994-01-01

    on polytetrafluorine-ethyl bonded gas-diffusion electordes in phosphoric acid with and without fluorinated additives. This provides an alternative to estimate the film thickness by combining it with the acid-adsorption measurements and the porosity analysis of the catalyst layer. It was noticed that the limiting...... expression for the limiting current density. The acid-film thickness estimated this way was found to be of 0.1 mum order of magnitude for the two types of electrodes used in phosphoric acid with and without fluorinated additives at 150-degrees-C....

  7. Accumulation and Clearance of Perfluorooctanoic Acid (PFOA) in Current and Former Residents of an Exposed Community

    Seals, Ryan; Bartell, Scott M; Steenland, Kyle

    2010-01-01

    Background Perfluorooctanoic acid (PFOA) is a perfluoroalkyl acid found in > 99% of Americans. Its health effects are unknown. Prior estimates of serum half-life range from 2.3 to 3.8 years. Objectives We assessed the impact of years of residence and years since residing in the study area on serum PFOA concentration in a sample of current and former residents who were exposed to PFOA emissions from an industrial facility in six water districts in West Virginia and Ohio. Methods Serum samples ...

  8. Accumulation and Clearance of Perfluorooctanoic Acid (PFOA) in Current and Former Residents of an Exposed Community

    Seals, Ryan; Bartell, Scott M; Steenland, Kyle

    2010-01-01

    Background: Perfluorooctanoic acid (PFOA) is a perfluoroalkyl acid found in > 99% of Americans. Its health effects are unknown. Prior estimates of serum half-life range from 2.3 to 3.8 years. Objectives: We assessed the impact of years of residence and years since residing in the study area on serum PFOA concentration in a sample of current and former residents who were exposed to PFOA emissions from an industrial facility in six water districts in West Virginia and Ohio. Methods: Serum sampl...

  9. Accumulation of sigmaS due to enhanced synthesis and decreased degradation in acidic phospholipid-deficient Escherichia coli cells.

    Uchiyama, Junji; Sasaki, Yu; Nagahama, Hideki; Itou, Aya; Matsuoka, Satoshi; Matsumoto, Kouji; Hara, Hiroshi

    2010-06-01

    The Escherichia coli pgsA3 mutation, which causes deficiency in acidic phospholipids, leads to a significant accumulation of sigma(S). This accumulation is partly accounted for by the higher transcription level of rpoS; however, it has also been suggested that the cells accumulate sigma(S) post-transcriptionally. We found that the level of the small regulatory RNA RprA, which is involved in the promotion of rpoS translation, is higher in pgsA3 cells than in pgsA(+) cells. Induction of altered rpoS mRNA that does not depend on RprA in pgsA(+) cells did not increase the level of sigma(S) to the high level observed in pgsA3 cells, suggesting post-translational sigma(S) accumulation in the latter. The mRNA levels of clpX and clpP, whose products form a ClpXP protease that degrades sigma(S), were much reduced in pgsA3 cells. Consistent with the reduced mRNA levels, the half-life of sigma(S) in pgsA3 cells was much longer than in pgsA(+) cells, indicating that downregulation of the degradation is a major cause for the high sigma(S) content. We show that the downregulation can be partially attributed to activated CpxAR in the mutant cells, which causes repression of rpoE on whose gene product the expression of clpPX depends. PMID:20455949

  10. Gibberellic acid alleviates cadmium toxicity by reducing nitric oxide accumulation and expression of IRT1 in Arabidopsis thaliana

    Zhu, Xiao Fang [State Key Laboratory of Plant Physiology and Biochemistry, College of Life Sciences, Zhejiang University, Hangzhou 310058 (China); Jiang, Tao [Key Laboratory of Conservation Biology for Endangered Wildlife of the Ministry of Education, College of Life Sciences, Zhejiang University, Hangzhou 310058 (China); Wang, Zhi Wei [State Key Laboratory of Plant Physiology and Biochemistry, College of Life Sciences, Zhejiang University, Hangzhou 310058 (China); Lei, Gui Jie [Key Laboratory of Conservation Biology for Endangered Wildlife of the Ministry of Education, College of Life Sciences, Zhejiang University, Hangzhou 310058 (China); Shi, Yuan Zhi [The Key Laboratory of Tea Chemical Engineering, Ministry of Agriculture, Yunqi Road 1, Hangzhou 310008 (China); Li, Gui Xin, E-mail: guixinli@zju.edu.cn [College of Agronomy and Biotechnology, Zhejiang University, Hangzhou 310058 (China); Zheng, Shao Jian [State Key Laboratory of Plant Physiology and Biochemistry, College of Life Sciences, Zhejiang University, Hangzhou 310058 (China); Key Laboratory of Conservation Biology for Endangered Wildlife of the Ministry of Education, College of Life Sciences, Zhejiang University, Hangzhou 310058 (China)

    2012-11-15

    Highlights: Black-Right-Pointing-Pointer Cd reduces endogenous GA levels in Arabidopsis. Black-Right-Pointing-Pointer GA exogenous applied decreases Cd accumulation in plant. Black-Right-Pointing-Pointer GA suppresses the Cd-induced accumulation of NO. Black-Right-Pointing-Pointer Decreased NO level downregulates the expression of IRT1. Black-Right-Pointing-Pointer Suppressed IRT1 expression reduces Cd transport across plasma membrane. - Abstract: Gibberellic acid (GA) is involved in not only plant growth and development but also plant responses to abiotic stresses. Here it was found that treating the plants with GA concentrations from 0.1 to 5 {mu}M for 24 h had no obvious effect on root elongation in the absence of cadmium (Cd), whereas in the presence of Cd{sup 2+}, GA at 5 {mu}M improved root growth, reduced Cd content and lipid peroxidation in the roots, indicating that GA can partially alleviate Cd toxicity. Cd{sup 2+} increased nitric oxide (NO) accumulation in the roots, but GA remarkably reduced it, and suppressed the up-regulation of the expression of IRT1. In contrary, the beneficial effect of GA on alleviating Cd toxicity was not observed in an IRT1 knock-out mutant irt1, suggesting the involvement of IRT1 in Cd{sup 2+} absorption. Furthermore, the GA-induced reduction of NO and Cd content can also be partially reversed by the application of a NO donor (S-nitrosoglutathione [GSNO]). Taken all these together, the results showed that GA-alleviated Cd toxicity is mediated through the reduction of the Cd-dependent NO accumulation and expression of Cd{sup 2+} uptake related gene-IRT1 in Arabidopsis.

  11. Loss of cation-independent mannose 6-phosphate receptor expression promotes the accumulation of lysobisphosphatidic acid in multilamellar bodies.

    Reaves, B J; Row, P E; Bright, N A; Luzio, J P; Davidson, H W

    2000-11-01

    A number of recent studies have highlighted the importance of lipid domains within endocytic organelles in the sorting and movement of integral membrane proteins. In particular, considerable attention has become focussed upon the role of the unusual phospholipid lysobisphosphatidic acid (LBPA). This lipid appears to be directly involved in the trafficking of cholesterol and glycosphingolipids, and accumulates in a number of lysosomal storage disorders. Antibody-mediated disruption of LBPA function also leads to mis-sorting of cation-independent mannose 6-phosphate receptors. We now report that the converse is also true, and that spontaneous loss of cation-independent mannose 6-phosphate receptors from a rat fibroblast cell line led to the formation of aberrant late endocytic structures enriched in LBPA. Accumulation of LBPA was directly dependent upon the loss of the receptors, and could be reversed by expression of bovine cation-independent mannose 6-phosphate receptors in the mutant cell line. Ultrastructural analysis indicated that the abnormal organelles were electron-dense, had a multi-lamellar structure, accumulated endocytosed probes, and were distinct from dense-core lysosomes present within the same cells. The late endocytic structures present at steady state within any particular cell likely reflect the balance of membrane traffic through the endocytic pathway of that cell, and the rate of maturation of individual endocytic organelles. Moreover, there is considerable evidence which suggests that cargo receptors also play a direct mechanistic role in membrane trafficking events. Therefore, loss of such a protein may disturb the overall equilibrium of the pathway, and hence cause the accumulation of aberrant organelles. We propose that this mechanism underlies the phenotype of the mutant cell line, and that the formation of inclusion bodies in many lysosomal storage diseases is also due to an imbalance in membrane trafficking within the endocytic pathway

  12. The plant immunity inducer pipecolic acid accumulates in the xylem sap and leaves of soybean seedlings following Fusarium virguliforme infection.

    Abeysekara, Nilwala S; Swaminathan, Sivakumar; Desai, Nalini; Guo, Lining; Bhattacharyya, Madan K

    2016-02-01

    The causal agent of the soybean sudden death syndrome (SDS), Fusarium virguliforme, remains in infected roots and secretes toxins to cause foliar SDS. In this study we investigated the xylem sap, roots, and leaves of F. virguliforme-infected and -uninfected soybean seedlings for any changes in a set of over 3,000 metabolites following pathogen infection by conducting GC/MS and LC/MS/MS, and detected 273 biochemicals. Levels of many intermediates of the TCA cycle were reduced suggesting suppression of this metabolic pathway by the pathogen. There was an increased accumulation of peroxidated lipids in leaves of F. virguliforme-infected plants suggesting possible involvement of free radicals and lipoxygenases in foliar SDS development. Levels of both isoflavone conjugates and isoflavonoid phytoalexins were decreased in infected roots suggesting degradation of these metabolites by the pathogen to promote root necrosis. The levels of the plant immunity inducer pipecolic acid (Pip) and the plant hormone salicylic acid (SA) were significantly increased in xylem sap (in case of Pip) and leaves (in case of both Pip and SA) of F. virguliforme-infected soybean plants compared to the control plants. This suggests a major signaling role of Pip in inducing host defense responses in above ground parts of the F. virguliforme-infected soybean. Increased accumulation of pipecolic acid in foliar tissues was associated with the induction of GmALD1, the soybean homolog of Arabidopsis ALD1. This metabolomics study generated several novel hypotheses for studying the mechanisms of SDS development in soybean. PMID:26795155

  13. Amino acid limitation induces down-regulation of WNT5a at transcriptional level

    An aberrant WNT signaling contributes to the development and progression of multiple cancers. WNT5a is one of the WNT signaling molecules. This study was designed to test the hypothesis that amino acid deprivation induces changes in the WNT signaling pathway in colon cancer cells. Results showed that targets of the amino acid response pathway, ATF3 and p21, were induced in the human colon cancer cell line SW480 during amino acid limitation. There was a significant decrease in the WNT5a mRNA level following amino acid deprivation. The down-regulation of WNT5a mRNA by amino acid deprivation is not due to mRNA destabilization. There is a reduction of nuclear β-catenin protein level by amino acid limitation. Under amino acid limitation, phosphorylation of ERK1/2 was increased and the blockage of ERK1/2 by the inhibitor U0126 partially restored WNT5a mRNA level. In conclusion, amino acid limitation in colon cancer cells induces phosphorylation of ERK1/2, which then down-regulates WNT5a expression.

  14. Simultaneous effect of nitrate (NO3- concentration, carbon dioxide (CO2 supply and nitrogen limitation on biomass, lipids, carbohydrates and proteins accumulation in Nannochloropsis oculata

    Aarón Millán-Oropeza

    2015-03-01

    Full Text Available Biodiesel from microalgae is a promising technology. Nutrient limitation and the addition of CO2 are two strategies to increase lipid content in microalgae. There are two different types of nitrogen limitation, progressive and abrupt limitation. In this work, the simultaneous effect of initial nitrate concentration, addition of CO2, and nitrogen limitation on biomass, lipid, protein and carbohydrates accumulation were analyzed. An experimental design was established in which initial nitrogen concentration, culture time and CO2 aeration as independent numerical variables with three levels were considered. Nitrogen limitation was taken into account as a categorical independent variable. For the experimental design, all the experiments were performed with progressive nitrogen limitation. The dependent response variables were biomass, lipid production, carbohydrates and proteins. Subsequently, comparison of both types of limitation i.e. progressive and abrupt limitation, was performed. Nitrogen limitation in a progressive mode exerted a greater effect on lipid accumulation. Culture time, nitrogen limitation and the interaction of initial nitrate concentration with nitrogen limitation had higher influences on lipids and biomass production. The highest lipid production and productivity were at 582 mgL-1 (49.7 % lipid, dry weight basis and 41.5 mgL-1d-1, respectively; under the following conditions: 250 mgL-1 of initial nitrate concentration, CO2 supply of 4% (v/v, 12 d of culturing and 2 d in state of nitrogen starvation induced by progressive limitation. This work presents a novel way to perform simultaneous analysis of the effect of the initial concentration of nitrate, nitrogen limitation, and CO2 supply on growth and lipid production of Nannochloropsis oculata, with the aim to produce potential biofuels feedstock.

  15. SFH2 regulates fatty acid synthase activity in the yeast Saccharomyces cerevisiae and is critical to prevent saturated fatty acid accumulation in response to haem and oleic acid depletion.

    Desfougères, Thomas; Ferreira, Thierry; Bergès, Thierry; Régnacq, Matthieu

    2008-01-01

    The yeast Saccharomyces cerevisiae is a facultative anaerobic organism. Under anaerobiosis, sustained growth relies on the presence of exogenously supplied unsaturated fatty acids and ergosterol that yeast is unable to synthesize in the absence of oxygen or upon haem depletion. In the absence of exogenous supplementation with unsaturated fatty acid, a net accumulation of SFA (saturated fatty acid) is observed that induces significant modification of phospholipid profile [Ferreira, Régnacq, Alimardani, Moreau-Vauzelle and Bergès (2004) Biochem. J. 378, 899-908]. In the present paper, we focus on the role of SFH2/CSR1, a hypoxic gene related to SEC14 and its involvement in lipid metabolism upon haem depletion in the absence of oleic acid supplementation. We observed that inactivation of SFH2 results in enhanced accumulation of SFA and phospholipid metabolism alterations. It results in premature growth arrest and leads to an exacerbated sensitivity to exogenous SFA. This phenotype is suppressed in the presence of exogenous oleic acid, or by a controlled expression of FAS1, one of the two genes encoding FAS. We present several lines of evidence to suggest that Sfh2p and oleic acid regulate SFA synthase in yeast at different levels: whereas oleic acid acts on FAS2 at the transcriptional level, we show that Sfh2p inhibits fatty acid synthase activity in response to haem depletion. PMID:17803462

  16. 1-FFT amino acids involved in high DP inulin accumulation in Viguiera discolor

    Emerik eDe Sadeleer

    2015-08-01

    Full Text Available Fructans are important vacuolar reserve carbohydrates with drought, cold, ROS and general abiotic stress mediating properties. They occur in 15% of all flowering plants and are believed to display health benefits as a prebiotic and dietary fiber. Fructans are synthesized by specific fruc- tosyltransferases and classified based on the linkage type between fructosyl units. Inulins, one of these fructan types with β(2-1 linkages, are elongated by fructan:fructan 1-fructosyltransferases (1-FFT using a fructosyl unit from a donor inulin to elongate the acceptor inulin molecule. The sequence identity of the 1-FFT of Viguiera discolor (Vd and Helianthus tuberosus (Ht is 91% although these enzymes produce distinct fructans. The Vd 1-FFT produces high degree of poly- merization (DP inulins by preferring the elongation of long chain inulins, in contrast to the Ht 1-FFT which prefers small molecules (DP3 or 4 as acceptor. Since higher DP inulins have in- teresting properties for industrial, food and medical applications, we report here on the influence of two amino acids on the high DP inulin production capacity of the Vd 1-FFT. Introducing the M19F and H308T mutations in the active site of the Vd 1-FFT greatly reduces its capacity to pro- duce high DP inulin molecules. Both amino acids can be considered important to this capacity, although the double mutation had a much higher impact than the single mutations.

  17. Trichoderma inoculation augments grain amino acids and mineral nutrients by modulating arsenic speciation and accumulation in chickpea (Cicer arietinum L.).

    Tripathi, Pratibha; Singh, Poonam C; Mishra, Aradhana; Tripathi, Rudra D; Nautiyal, Chandra S

    2015-07-01

    Trichoderma reesei is an industrially important fungi which also imparts stress tolerance and plant growth promotion in various crops. Arsenic (As) contamination of field soils is one of the challenging problems in agriculture, posing potential threats for both human health and the environment. Plants in association with microbes are a liable method to improve metal tolerance and enhance crop productivity. Chickpea (Cicer arietinum L.), is an important grain legume providing cheap source of protein in semi-arid regions including As affected areas. In this study we report the role of T. reesei NBRI 0716 (NBRI 0716) in supporting chickpea growth and improving soil quality in As simulated conditions. NBRI 0716 modulated the As speciation and its availability to improve grain yield and quality (amino acids and mineral content) in chickpea (C. arietinum L.) plants grown in As spiked soil (100 mg As kg(-1) soil). Arsenic accumulation and speciation results indicate that arsenate [As(V)] was the dominant species in chickpea seeds and rhizosphere soil. The Trichoderma reduced total grain inorganic As (Asi) by 66% and enhanced dimethylarsonic acid (DMA) and monomethylarsinic acid (MMA) content of seed and rhizosphere soil. The results indicate a probable role of NBRI 0716 in As methylation as the possible mechanism for maneuvering As stress in chickpea. Analysis of functional diversity using carbon source utilization (Biolog) showed significant difference in diversity and evenness indices among the soil microbial rhizosphere communities. Microbial diversity loss caused by As were prevented in the presence of Trichoderma NBRI 0716. PMID:25839184

  18. Analysis of Organic Acids Accumulated in Kochia Scoparia Shoots and Roots by Reverse-phase High Performance Liquid Chromatography Under Salt and Alkali Stress

    2006-01-01

    Several organic acids accumulated in Kochia Scoparia shoots and roots were studied by means of reverse-phase high performance liquid chromatography with a C18 column. Five types of binary organic acids were separated. The organic acid concentrations were determined in K. Scoparia seedlings stressed by saline (NaCl) and alkaline(NaHCO3) at the same Na + concentration. Concentrations of organic acids are stimulated by alkaline because the cells will adjust their pH values through the accumulation of organic acids, when the environment is basic. The concentrations of oxalic acid and succinic acid are higher than those of other organic acids, including tartaric acid and malic acid, and the concentration of citric acid is the lowest. The concentrations of the organic acids in the roots are higher than those in the shoots under salt(NaCl) stress, but the results are opposite while the roots are under alkali (NaHCO3) stress. This indicates that there are different adaptive strategies for K. Scoparia seedlings in organic acid metabolism under salt and alkali stress.

  19. Accumulation of Phenolic Compounds and Expression Profiles of Phenolic Acid Biosynthesis-Related Genes in Developing Grains of White, Purple, and Red Wheat

    Ma, Dongyun; Li, Yaoguang; Zhang, Jian; Wang, Chenyang; Qin, Haixia; Ding, Huina; Xie, Yingxin; Guo, Tiancai

    2016-01-01

    Polyphenols in whole grain wheat have potential health benefits, but little is known about the expression patterns of phenolic acid biosynthesis genes and the accumulation of phenolic acid compounds in different-colored wheat grains. We found that purple wheat varieties had the highest total phenolic content (TPC) and antioxidant activity. Among phenolic acid compounds, bound ferulic acid, vanillic, and caffeic acid levels were significantly higher in purple wheat than in white and red wheat, while total soluble phenolic acid, soluble ferulic acid, and vanillic acid levels were significantly higher in purple and red wheat than in white wheat. Ferulic acid and syringic acid levels peaked at 14 days after anthesis (DAA), whereas p-coumaric acid and caffeic acid levels peaked at 7 DAA, and vanillic acid levels gradually increased during grain filling and peaked near ripeness (35 DAA). Nine phenolic acid biosynthesis pathway genes (TaPAL1, TaPAL2, TaC3H1, TaC3H2, TaC4H, Ta4CL1, Ta4CL2, TaCOMT1, and TaCOMT2) exhibited three distinct expression patterns during grain filling, which may be related to the different phenolic acids levels. White wheat had higher phenolic acid contents and relatively high gene expression at the early stage, while purple wheat had the highest phenolic acid contents and gene expression levels at later stages. These results suggest that the expression of phenolic acid biosynthesis genes may be closely related to phenolic acids accumulation. PMID:27148345

  20. Accumulation of Phenolic Compounds and Expression Profiles of Phenolic Acid Biosynthesis-Related Genes in Developing Grains of White, Purple, and Red Wheat.

    Ma, Dongyun; Li, Yaoguang; Zhang, Jian; Wang, Chenyang; Qin, Haixia; Ding, Huina; Xie, Yingxin; Guo, Tiancai

    2016-01-01

    Polyphenols in whole grain wheat have potential health benefits, but little is known about the expression patterns of phenolic acid biosynthesis genes and the accumulation of phenolic acid compounds in different-colored wheat grains. We found that purple wheat varieties had the highest total phenolic content (TPC) and antioxidant activity. Among phenolic acid compounds, bound ferulic acid, vanillic, and caffeic acid levels were significantly higher in purple wheat than in white and red wheat, while total soluble phenolic acid, soluble ferulic acid, and vanillic acid levels were significantly higher in purple and red wheat than in white wheat. Ferulic acid and syringic acid levels peaked at 14 days after anthesis (DAA), whereas p-coumaric acid and caffeic acid levels peaked at 7 DAA, and vanillic acid levels gradually increased during grain filling and peaked near ripeness (35 DAA). Nine phenolic acid biosynthesis pathway genes (TaPAL1, TaPAL2, TaC3H1, TaC3H2, TaC4H, Ta4CL1, Ta4CL2, TaCOMT1, and TaCOMT2) exhibited three distinct expression patterns during grain filling, which may be related to the different phenolic acids levels. White wheat had higher phenolic acid contents and relatively high gene expression at the early stage, while purple wheat had the highest phenolic acid contents and gene expression levels at later stages. These results suggest that the expression of phenolic acid biosynthesis genes may be closely related to phenolic acids accumulation. PMID:27148345

  1. Inhibition of norsolorinic acid accumulation to Aspergillus parasiticus by marine actinomycetes

    Yan, Peisheng; Shi, Cuijuan; Shen, Jihong; Wang, Kai; Gao, Xiujun; Li, Ping

    2014-11-01

    Thirty-six strains of marine actinomycetes were isolated from a sample of marine sediment collected from the Yellow Sea and evaluated in terms of their inhibitory activity on the growth of Aspergillus parasiticus and the production of norsolorinic acid using dual culture plate assay and agar diffusion methods. Among them, three strains showed strong antifungal activity and were subsequently identified as Streptomyces sp. by 16S rRNA gene sequencing analysis. The supernatant from the fermentation of the MA01 strain was extracted sequentially with chloroform and ethyl acetate, and the activities of the extracts were determined by tip culture assay. The assay results show that both extracts inhibited mycelium growth and toxin production, and the inhibitory activities of the extracts increased as their concentrations increased. The results of this study suggest that marine actinomycetes are biologically important for the control of mycotoxins, and that these bacteria could be used as novel biopesticides against mycotoxins.

  2. Effects of salicylic acid on thermotolerance and cardenolide accumulation under high temperature stress in Digitalis trojana Ivanina.

    Cingoz, Gunce Sahin; Gurel, Ekrem

    2016-08-01

    Long periods of high temperature or transitory increased temperature, a widespread agricultural problem, may lead to a drastic reduction in economic yield, affecting plant growth and development in many areas of the world. Heat stress causes many anatomical and physiological changes in plants. Its unfavorable effects can be alleviated by thermotolerance induced by exogenous application of plant growth regulators and osmoprotectants or by gradual application of temperature stress. Digitalis trojana Ivanina is an important medicinal plant species well known mainly for its cardenolides. The production of cardenolides via traditional agriculture is commercially inadequate. In this study, elicitation strategies were employed for improving crop thermotolerance and accumulation of cardenolides. For these purposes, the effects of salicylic acid (SA) and/or high temperature treatments in inducing cardenolide accumulation and thermotolerance were tested in callus cultures of D. trojana. Considerable increases in the production of cardenolides (up to 472.28 μg.g(-1) dry weight, dw) and induction of thermotolerance capacity were observed when callus cultures were exposed to high temperature for 2 h after pretreating with SA. High temperature treatments (2 h and 4 h) caused a marked reduction in superoxide dismutase (SOD; EC 1.15.1.1) and catalase (CAT; EC 1.11.1.6) activities, while SA pretreatment increased their activities. High temperature and/or SA appeared to increase the levels of proline, total phenolic, and flavonoid content. Elevated phenolic accumulation could be associated with increased stress protection. These results indicated that SA treatments induced synthesis of antioxidants and cardenolides, which may play a significant role in resistance to high temperature stress. PMID:27105421

  3. Involvement of indole-3-acetic acid produced by Azospirillum brasilense in accumulating intracellular ammonium in Chlorella vulgaris.

    Meza, Beatriz; de-Bashan, Luz E; Bashan, Yoav

    2015-01-01

    Accumulation of intracellular ammonium and activities of the enzymes glutamine synthetase (GS) and glutamate dehydrogenase (GDH) were measured when the microalgae Chlorella vulgaris was immobilized in alginate with either of two wild type strains of Azospirillum brasilense or their corresponding indole-3-acetic acid (IAA)-attenuated mutants. After 48 h of immobilization, both wild types induced higher levels of intracellular ammonium in the microalgae than their respective mutants; the more IAA produced, the higher the intracellular ammonium accumulated. Accumulation of intracellular ammonium in the cells of C. vulgaris followed application of four levels of exogenous IAA reported for A. brasilense and its IAA-attenuated mutants, which had a similar pattern for the first 24 h. This effect was transient and disappeared after 48 h of incubation. Immobilization of C. vulgaris with any bacteria strain induced higher GS activity. The bacterial strains also had GS activity, comparable to the activity detected in C. vulgaris, but weaker than when immobilized with the bacteria. When net activity was calculated, the wild type always induced higher GS activity than IAA-attenuated mutants. GDH activity in most microalgae/bacteria interactions resembled GS activity. When complementing IAA-attenuated mutants with exogenous IAA, GS activity in co-immobilized cultures matched those of the wild type A. brasilense immobilized with the microalga. Similarity occurred when the net GS activity was measured, and was higher with greater quantities of exogenous IAA. It is proposed that IAA produced by A. brasilense is involved in ammonium uptake and later assimilation by C. vulgaris. PMID:25554489

  4. Resistance of Streptococcus bovis to acetic acid at low pH: Relationship between intracellular pH and anion accumulation

    Streptococcus bovis JB1, an acid-tolerant ruminal bacterium, was able to grown at pHs from 6.7 to 4.5, and 100 mM acetate had little effect on growth rate or proton motive force across the cell membrane. When S. bovis was grown in glucose-limited chemostats at pH 5.2, the addition of sodium acetate (as much as 100 mM) had little effect on the production of bacterial protein. At higher concentrations of sodium acetate (100 to 360 mM), production of bacterial protein declined, but this decrease could largely be explained by a shift in fermentation products (acetate, formate, and ethanol production to lactate production) and a decline in ATP production (3 ATP per glucose versus 2 ATP per glucose). YATP (grams of cells per mole at ATP) was not decreased significantly even by high concentrations of acetate. Cultures supplemented with 100 mM sodium acetate took up [14C]acetate and [14C]benzoate in accordance with the Henderson-Hasselbalch equation and gave similar estimates of intracellular pH. As the extracellular pH declined, S. bovis allowed its intracellular pH to decrease and maintained a relatively constant pH gradient across the cell membrane (0.9 unit). The decrease in intracellular pH prevented S. bovis from accumulating large amounts of acetate anion. On the basis of these results it did not appear that acetate was acting as an uncoupler. The sensitivity of other bacteria to volatile fatty acids at low pH is explained most easily by a high transmembrane pH gradient and anion accumulation

  5. Sulfur alleviates arsenic toxicity by reducing its accumulation and modulating proteome, amino acids and thiol metabolism in rice leaves

    Dixit, Garima; Singh, Amit Pal; Kumar, Amit; Dwivedi, Sanjay; Deeba, Farah; Kumar, Smita; Suman, Shankar; Adhikari, Bijan; Shukla, Yogeshwar; Trivedi, Prabodh Kumar; Pandey, Vivek; Tripathi, Rudra Deo

    2015-11-01

    Arsenic (As) contamination of water is a global concern and rice consumption is the biggest dietary exposure to human posing carcinogenic risks, predominantly in Asia. Sulfur (S) is involved in di-sulfide linkage in many proteins and plays crucial role in As detoxification. Present study explores role of variable S supply on rice leaf proteome, its inclination towards amino acids (AA) profile and non protein thiols under arsenite exposure. Analysis of 282 detected proteins on 2-DE gel revealed 113 differentially expressed proteins, out of which 80 were identified by MALDI-TOF-TOF. The identified proteins were mostly involved in glycolysis, TCA cycle, AA biosynthesis, photosynthesis, protein metabolism, stress and energy metabolism. Among these, glycolytic enzymes play a major role in AA biosynthesis that leads to change in AAs profiling. Proteins of glycolytic pathway, photosynthesis and energy metabolism were also validated by western blot analysis. Conclusively S supplementation reduced the As accumulation in shoot positively skewed thiol metabolism and glycolysis towards AA accumulation under AsIII stress.

  6. Ascorbic acid enhances the accumulation of polycyclic aromatic hydrocarbons (PAHs in roots of tall fescue (Festuca arundinacea Schreb..

    Yanzheng Gao

    Full Text Available Plant contamination by polycyclic aromatic hydrocarbons (PAHs is crucial to food safety and human health. Enzyme inhibitors are commonly utilized in agriculture to control plant metabolism of organic components. This study revealed that the enzyme inhibitor ascorbic acid (AA significantly reduced the activities of peroxidase (POD and polyphenol oxidase (PPO, thus enhancing the potential risks of PAH contamination in tall fescue (Festuca arundinacea Schreb.. POD and PPO enzymes in vitro effectively decomposed naphthalene (NAP, phenanthrene (PHE and anthracene (ANT. The presence of AA reduced POD and PPO activities in plants, and thus was likely responsible for enhanced PAH accumulation in tall fescue. This conclusion is supported by the significantly enhanced uptake of PHE in plants in the presence of AA, and the positive correlation between enzyme inhibition efficiencies and the rates of metabolism of PHE in tall fescue roots. This study provides a new perspective, that the common application of enzyme inhibitors in agricultural production could increase the accumulation of organic contaminants in plants, hence enhancing risks to food safety and quality.

  7. Foliar abscisic acid-to-ethylene accumulation and response regulate shoot growth sensitivity to mild drought in wheat

    Ravi eValluru

    2016-04-01

    Full Text Available Although plant hormones play an important role in adjusting growth in response to environmental perturbation, the relative contributions of abscisic acid (ABA and ethylene remain elusive. Using six spring wheat genotypes differing for stress tolerance, we show that young seedlings of the drought-tolerant (DT group maintained or increased shoot dry weight (SDW while the drought-susceptible (DS group decreased SDW in response to mild drought. Both the DT and DS groups increased endogenous ABA and ethylene concentrations under mild drought compared to control. The DT and DS groups exhibited different SDW response trends, whereby the DS group decreased while the DT group increased SDW, to increased concentrations of ABA and ethylene under mild drought, although both groups decreased ABA/ethylene ratio under mild drought albeit at different levels. We concluded that SDW of the DT and DS groups might be distinctly regulated by specific ABA:ethylene ratio. Further, a foliar-spray of low concentrations (0.1 μM of ABA increased shoot relative growth rate (RGR in the DS group while ACC (1-aminocyclopropane-1-carboxylic acid, ethylene precursor spray increased RGR in both groups compared to control. Furthermore, the DT group accumulated a significantly higher galactose while a significantly lower maltose in the shoot compared to the DS group. Taken all together, these results suggest an impact of ABA, ethylene and ABA:ethylene ratio on SDW of wheat seedlings that may partly underlie a genotypic variability of different shoot growth sensitivities to drought among crop species under field conditions. We propose that phenotyping based on hormone accumulation, response and hormonal ratio would be a viable, rapid, and an early–stage selection tool aiding genotype selection for stress tolerance.

  8. Foliar Abscisic Acid-To-Ethylene Accumulation and Response Regulate Shoot Growth Sensitivity to Mild Drought in Wheat.

    Valluru, Ravi; Davies, William J; Reynolds, Matthew P; Dodd, Ian C

    2016-01-01

    Although, plant hormones play an important role in adjusting growth in response to environmental perturbation, the relative contributions of abscisic acid (ABA) and ethylene remain elusive. Using six spring wheat genotypes differing for stress tolerance, we show that young seedlings of the drought-tolerant (DT) group maintained or increased shoot dry weight (SDW) while the drought-susceptible (DS) group decreased SDW in response to mild drought. Both the DT and DS groups increased endogenous ABA and ethylene concentrations under mild drought compared to control. The DT and DS groups exhibited different SDW response trends, whereby the DS group decreased while the DT group increased SDW, to increased concentrations of ABA and ethylene under mild drought, although both groups decreased ABA/ethylene ratio under mild drought albeit at different levels. We concluded that SDW of the DT and DS groups might be distinctly regulated by specific ABA:ethylene ratio. Further, a foliar-spray of low concentrations (0.1 μM) of ABA increased shoot relative growth rate (RGR) in the DS group while ACC (1-aminocyclopropane-1-carboxylic acid, ethylene precursor) spray increased RGR in both groups compared to control. Furthermore, the DT group accumulated a significantly higher galactose while a significantly lower maltose in the shoot compared to the DS group. Taken all together, these results suggest an impact of ABA, ethylene, and ABA:ethylene ratio on SDW of wheat seedlings that may partly underlie a genotypic variability of different shoot growth sensitivities to drought among crop species under field conditions. We propose that phenotyping based on hormone accumulation, response and hormonal ratio would be a viable, rapid, and an early-stage selection tool aiding genotype selection for stress tolerance. PMID:27148292

  9. On the state of jumus accumulation observed in soil profile and the contents of sugar, uronic acid and amino acid in fulvic acid fraction

    In a previous report, the author wrote on the form of volcanic soil in Onohara, Tarumi City, which consists of about fourty soil layers, and seventeen of which contain more than 0.69% total carbon. The present report is concerned with the result of determination of 1) carbon and nitrogen contents of the soil and its fulvic acid, humic acid and humine, 2) sugar, uronic acid and amino acid contents and amino acid composition of fulvic acid fraction, and 3) 14C age of some soil layers. Methods of sample preparation and content determination are briefly given, and the results are shown. 14C age ranged from some 5500 to 9300 yr. B. P. In general tendency, as the carbon content of a soil layer is higher, its C/N ratio is higher, and C/N ratio of fulvic acid Fraction is almost constant (10-13) in all samples. The total content of sugar, uronic acid and hydrolytic amino acid is 30-40% of that of fulvic acid and almost invariable for all layers, 19-25% of which being occupied by the first two. (Shibata, I.)

  10. Reduced Inflammation in the Tumor Microenvironment Delays the Accumulation of Myeloid-Derived Suppressor Cells and Limits Tumor Progression

    Bunt, Stephanie K.; YANG, LINGLIN; Sinha, Pratima; Clements, Virginia K.; Leips, Jeff; Ostrand-Rosenberg, Suzanne

    2007-01-01

    Chronic inflammation is frequently associated with malignant growth and is thought to promote and enhance tumor progression, although the mechanisms which regulate this relationship remain elusive. We reported previously that interleukin (IL)-1β promoted tumor progression by enhancing the accumulation of myeloid-derived suppressor cells (MDSC), and hypothesized that inflammation leads to cancer through the production of MDSC which inhibit tumor immunity. If inflammation-induced MDSC promote t...

  11. Prevention of volatile fatty acids production and limitation of odours from winery wastewaters by denitrification.

    Bories, André; Guillot, Jean-Michel; Sire, Yannick; Couderc, Marie; Lemaire, Sophie-Andréa; Kreim, Virginie; Roux, Jean-Claude

    2007-07-01

    The effect of the addition of nitrate to winery wastewaters to control the formation of VFA in order to prevent odours during storage and treatment was studied in batch bioreactors at different NO(3)/chemical oxygen demand (COD) ratios and at full scale in natural evaporation ponds (2 x 7000 m(2)) by measuring olfactory intensity. In the absence of nitrate, butyric acid (2304 mgL(-1)), acetic acid (1633 mgL(-1)), propionic acid (1558 mgL(-1)), caproic acid (499 mgL(-1)) and valeric acid (298 mgL(-1)) were produced from reconstituted winery wastewater. For a ratio of NO(3)/COD=0.4 gg(-1), caproic and valeric acids were not formed. The production of butyric and propionic acids was reduced by 93.3% and 72.5%, respectively, at a ratio of NO(3)/COD=0.8, and by 97.4% and 100% at a ratio of NO(3)/COD=1.2 gg(-1). Nitrate delayed and decreased butyric acid formation in relation to the oxidoreduction potential. Studies in ponds showed that the addition of concentrated calcium nitrate (NITCAL) to winery wastewaters (3526 m(3)) in a ratio of NO(3)/COD=0.8 inhibited VFA production, with COD elimination (94%) and total nitrate degradation, and no final nitrite accumulation. On the contrary, in ponds not treated with nitrate, malodorous VFA (from propionic to heptanoïc acids) represented up to 60% of the COD. Olfactory intensity measurements in relation to the butanol scale of VFA solutions and the ponds revealed the pervasive role of VFA in the odour of the untreated pond as well as the clear decrease in the intensity and not unpleasant odour of the winery wastewater pond enriched in nitrates. The results obtained at full scale underscored the feasibility and safety of the calcium nitrate treatment as opposed to concentrated nitric acid. PMID:17467770

  12. NFX1-LIKE2 (NFXL2 suppresses abscisic acid accumulation and stomatal closure in Arabidopsis thaliana.

    Janina Lisso

    Full Text Available The NFX1-LIKE1 (NFXL1 and NFXL2 genes were identified as regulators of salt stress responses. The NFXL1 protein is a nuclear factor that positively affects adaptation to salt stress. The nfxl1-1 loss-of-function mutant displayed reduced survival rates under salt and high light stress. In contrast, the nfxl2-1 mutant, defective in the NFXL2 gene, and NFXL2-antisense plants exhibited enhanced survival under these conditions. We show here that the loss of NFXL2 function results in abscisic acid (ABA overaccumulation, reduced stomatal conductance, and enhanced survival under drought stress. The nfxl2-1 mutant displayed reduced stomatal aperture under all conditions tested. Fusicoccin treatment, exposition to increasing light intensities, and supply of decreasing CO(2 concentrations demonstrated full opening capacity of nfxl2-1 stomata. Reduced stomatal opening presumably is a consequence of elevated ABA levels. Furthermore, seedling growth, root growth, and stomatal closure were hypersensitive to exogenous ABA. The enhanced ABA responses may contribute to the improved drought stress resistance of the mutant. Three NFXL2 splice variants were cloned and named NFXL2-78, NFXL2-97, and NFXL2-100 according to the molecular weight of the putative proteins. Translational fusions to the green fluorescent protein suggest nuclear localisation of the NFXL2 proteins. Stable expression of the NFXL2-78 splice variant in nfxl2-1 plants largely complemented the mutant phenotype. Our data show that NFXL2 controls ABA levels and suppresses ABA responses. NFXL2 may prevent unnecessary and costly stress adaptation under favourable conditions.

  13. Implication of organic acids in the long-distance transport and the accumulation of lead in Sesuvium portulacastrum and Brassica juncea.

    Ghnaya, Tahar; Zaier, Hanen; Baioui, Raoudha; Sghaier, Souhir; Lucchini, Giorgio; Sacchi, Gian Attilio; Lutts, Stanley; Abdelly, Chedly

    2013-01-01

    The implication of organic acids in Pb translocation was studied in two species varying in shoot lead accumulation, Sesuvium portulacastrum and Brassica juncea. Citric, fumaric, malic and α-cetoglutaric acids were separated and determined by HPLC technique in shoots, roots and xylem saps of the both species grown in nutrient solutions added with 200 and 400 μM of Pb(II). The lead content of the xylem saps was determined by ICP-MS. Results showed that S. portulacastrum is more tolerant to Pb than B. juncea. Lead concentration in xylem sap of the S. portulacastrum was significantly greater than in that of B. juncea. For both species, a positive correlation was established between lead and citrate concentrations in xylem sap. However minor relationship was observed for fumaric, malic and α-cetoglutaric acids. In the shoots lead treatment also induced a significant increase in citric acid concentration. Both observations suggest the implication of citric acid in lead translocation and shoot accumulation in S. portulacastrum and B. juncea. The relatively high accumulation of citric acid in xylem sap and shoot of S. portulacastrum could explain its high potential to translocate and accumulate this metal in shoot suggesting their possible use to remediate Pb polluted soils. PMID:23026160

  14. Enhanced production of nitric oxide, reactive oxygen species, and pro-inflammatory cytokines in very long chain saturated fatty acid-accumulated macrophages

    Kiyanagi Takashi; Sumiyoshi Katsuhiko; Kitamura Yohei; Kume Atsumi; Miyazaki Tetsuro; Shimada Kazunori; Yanagisawa Naotake; Iesaki Takafumi; Inoue Nao; Daida Hiroyuki

    2008-01-01

    Abstract Background Deterioration of peroxisomal β-oxidation activity causes an accumulation of very long chain saturated fatty acids (VLCSFA) in various organs. We have recently reported that the levels of VLCSFA in the plasma and/or membranes of blood cells were significantly higher in patients with metabolic syndrome and in patients with coronary artery disease than the controls. The aim of the present study is to investigate the effect of VLCSFA accumulation on inflammatory and oxidative ...

  15. Cadmium and manganese accumulation in Phytolacca americana L. and the roles of non-protein thiols and organic acids.

    Gao, Lu; Peng, Kejian; Xia, Yan; Wang, Guiping; Niu, Liyuan; Lian, Chunlan; Shen, Zhenguo

    2013-01-01

    Phytolacca americana L. can accumulate large amounts of heavy metals in its aerial tissues, especially cadmium (Cd) and manganese (Mn). It has great potential for use in phytoextraction of metals from multi-metal-contaminated soils. This study was conducted to further investigate the Cd- and Mn-tolerance strategies of this plant. Concentrations of non-protein thiols (NPTs) and phytochelatins (PCs) in leaves and roots increased significantly as the concentration of Cd in solution increased. The molar ratios of PCs:soluble Cd ranged from 1.8 to 3.6 in roots and 8.1 to 31.6 in leaves, suggesting that the cellular response involving PC synthesis was sufficient to complex Cd ions in the cytosol, especially that of leaves. In contrast, excess Mn treatments did not result in a significant increase in NPT or PC concentrations in leaves or roots. Oxalic acid concentrations in leaves of plants exposed to 2 or 20 mM Mn reached 69.4 to 89.3 mg (0.771 to 0.992 mmol) g(-1) dry weight, respectively, which was approximately 3.7- to 8.6-fold higher than the Mn level in the 0.6 M HCl extract. Thus, oxalic acid may play an important role in the detoxification of Mn. PMID:23487997

  16. Transport and metabolism of fumaric acid in Saccharomyces cerevisiae in aerobic glucose-limited chemostat culture.

    Shah, Mihir V; van Mastrigt, Oscar; Heijnen, Joseph J; van Gulik, Walter M

    2016-04-01

    Currently, research is being focused on the industrial-scale production of fumaric acid and other relevant organic acids from renewable feedstocks via fermentation, preferably at low pH for better product recovery. However, at low pH a large fraction of the extracellular acid is present in the undissociated form, which is lipophilic and can diffuse into the cell. There have been no studies done on the impact of high extracellular concentrations of fumaric acid under aerobic conditions in S. cerevisiae, which is a relevant issue to study for industrial-scale production. In this work we studied the uptake and metabolism of fumaric acid in S. cerevisiae in glucose-limited chemostat cultures at a cultivation pH of 3.0 (pH exporting fumaric acid. We observed that fumaric acid entered the cells most likely via passive diffusion of the undissociated form. Approximately two-thirds of the fumaric acid in the feed was metabolized together with glucose. From metabolic flux analysis, an increased ATP dissipation was observed only at high intracellular concentrations of fumarate, possibly due to the export of fumarate via an ABC transporter. The implications of our results for the industrial-scale production of fumaric acid are discussed. Copyright © 2015 John Wiley & Sons, Ltd. PMID:26683700

  17. Active accumulation of internal DIC pools reduces transport limitation in large colonies of Nostoc pruniforme

    Raun, Ane-Marie Løvendahl; Borum, Jens; Jensen, Kaj Sand

    2009-01-01

    Nostoc pruniforme is a freshwater cyanobacterium forming large spherical colonies of up to several centimeters in diameter. The size and shape result in low surface area to volume (SA/V) ratios that potentially put severe constraints on resource acquisition. In the present study we have...... polysaccharides contains declining densities of trichomes with increasing colony size. N. pruniforme is a very efficient bicarbonate (HCO3-) user and, in addition, actively accumulates large pools of DIC that can support net photosynthesis for >22 h without a supply of external DIC. Both the efficient HCO3......- utilization and the large internal DIC pools greatly reduce N. pruniforme dependence on the immediate availability and species of external DIC. The location of the trichomes in the shell, the HCO3- utilization and the internal DIC pools mean that colony size only has a minor effect on photosynthetic rates as...

  18. Yeast Extract and Silver Nitrate Induce the Expression of Phenylpropanoid Biosynthetic Genes and Induce the Accumulation of Rosmarinic Acid in Agastache rugosa Cell Culture

    Woo Tae Park; Mariadhas Valan Arasu; Naif Abdullah Al-Dhabi; Sun Kyung Yeo; Jin Jeon; Jong Seok Park; Sook Young Lee; Sang Un Park

    2016-01-01

    The present study aimed to investigate the role of yeast extract and silver nitrate on the enhancement of phenylpropanoid pathway genes and accumulation of rosmarinic acid in Agastache rugosa cell cultures. The treatment of cell cultures with yeast extract (500 mg/L) and silver nitrate (30 mg/L) for varying times enhanced the expression of genes in the phenylpropanoid pathway and the production of rosmarinic acid. The results indicated that the expression of RAS and HPPR was proportional to t...

  19. Influence of different fertilization on the dissolved organic carbon, nitrogen and phosphorus accumulation in acid and limed soils

    Ieva Jokubauskaite

    2015-04-01

    Full Text Available Soil quality has become an important issue in soil science. Dissolved organic carbon (DOC is believed to play an important role in soil processes and in the C, N and P balances, their supplies to plants in all types of soils. It is much more sensitive to soil management than is soil organic matter as a whole, and can be used as a key indicator of soil natural functions. This study aimed to assess the influence of different organic fertilizers on DOC and N, P accumulation. The study was carried out on a moraine loam soil at the Vezaiciai Branch of Lithuanian Research Centre for Agriculture and Forestry in 2012. Farmyard manure (FYM (60 t ha -1 and alternative organic fertilizers (wheat straw, rape residues, roots, stubble, perennial grasses were applied on two soil backgrounds - acid and limed. DOC was analysed using an ion chromatograph SKALAR. Application of organic amendments resulted in a significant increase of soil organic carbon (SOC content, which demonstrates a positive role of organic fertilizers in SOC conservation. The combination of different organic fertilizers and liming had a significant positive effect on DOC concentration in the soil. The highest DOC content (0.241 g kg-1 was established in the limed soil fertilized with farmyard manure. The most unfavourable status of DOC was determined in the unlimed, unfertilized soil. The limed and FYM-applied soil had the highest nitrogen (1.47 g kg-1 and phosphorus (0.84 g kg-1 content compared to the other treatments. Organic fertilizers gave a significant positive effect on SOC and DOC content increase in the topsoil. This immediate increase is generally attributed to the presence of soluble materials in the amendments. Application of organic fertilizers in acid and limed soil increased the nutrient stocks and ensured soil chemical indicators at the optimal level for plant growth and thus may provide a mechanism as well as prediction opportunities for soil fertility, conservation

  20. β-Aminobutyric acid increases abscisic acid accumulation and desiccation tolerance and decreases water use but fails to improve grain yield in two spring wheat cultivars under soil drying

    Du, Yan-Lei; Wang, Zhen-Yu; Fan, Jing-Wei; Turner, Neil C.; Wang, Tao; Li, Feng-Min

    2012-01-01

    A pot experiment was conducted to investigate the effect of the non-protein amino acid, β-aminobutyric acid (BABA), on the homeostasis between reactive oxygen species (ROS) and antioxidant defence during progressive soil drying, and its relationship with the accumulation of abscisic acid (ABA), water use, grain yield, and desiccation tolerance in two spring wheat (Triticum aestivum L.) cultivars released in different decades and with different yields under drought. Drenching the soil with 100...

  1. Diets enriched in trans-11 vaccenic acid alleviate ectopic lipid accumulation in a rat model of NAFLD and metabolic syndrome.

    Jacome-Sosa, M Miriam; Borthwick, Faye; Mangat, Rabban; Uwiera, Richard; Reaney, Martin J; Shen, Jianheng; Quiroga, Ariel D; Jacobs, René L; Lehner, Richard; Proctor, Spencer D; Nelson, Randal C

    2014-07-01

    Trans11-18:1 (vaccenic acid, VA) is one of the most predominant naturally occurring trans fats in our food chain and has recently been shown to exert hypolipidemic effects in animal models. In this study, we reveal new mechanism(s) by which VA can alter body fat distribution, energy utilization and dysfunctional lipid metabolism in an animal model of obesity displaying features of the metabolic syndrome (MetS). Obese JCR:LA-cp rats were assigned to a control diet that included dairy-derived fat or the control diet supplemented with 1% VA. VA reduced total body fat (-6%), stimulated adipose tissue redistribution [reduced mesenteric fat (-17%) while increasing inguinal fat mass (29%)] and decreased adipocyte size (-44%) versus control rats. VA supplementation also increased metabolic rate (7%) concomitantly with an increased preference for whole-body glucose utilization for oxidation and increased insulin sensitivity [lower HOMA-IR (-59%)]. Further, VA decreased nonalcoholic fatty liver disease activity scores (-34%) and reduced hepatic (-27%) and intestinal (-39%) triglyceride secretion relative to control diet, while exerting differential transcriptional regulation of SREBP1 and FAS amongst other key genes in the liver and the intestine. Adding VA to dairy fat alleviates features of MetS potentially by remodeling adipose tissue and attenuating ectopic lipid accumulation in a rat model of obesity and MetS. Increasing VA content in the diet (naturally or by fortification) may be a useful approach to maximize the health value of dairy-derived fats. PMID:24775093

  2. Control of α-amylase mRNA accumulation by gibberellic acid and calcium in barley aleurone layers

    Pulse-labeling of barley (Hordeum vulgare L. cv Himalaya) aleurone layers incubated for 13 hours in 2.5 micromolar gibberellic acid (GA3) with or without 5 millimolar CaCl2 shows that α-amylase isozymes 3 and 4 are not synthesized in vivo in the absence of Ca2+. No difference was observed in α-amylase mRNA levels between layers incubated for 12 hours in 2.5 micromolar GA3 with 5 millimolar CaCl2 and layers incubated in GA3 alone. RNA isolated from layers incubated for 12 hours in GA3 with and without CA2+. A cDNA clone for α-amylase was isolated and used to measure α-amylase mRNA levels in aleurone layers incubated in the presence and absence of Ca2+ was translated in vitro and was found to produce the same complement of translation products regardless of the presence of Ca2+ in the incubation medium. Immunoprecipitation of translation products showed that the RNA for α-amylase synthesized in Ca2+-deprived aleurone layers was translatable. Ca2+ is required for the synthesis of α-amylase isozymes 3 and 4 at a step after mRNA accumulation and processing

  3. Toxic effects of oil sand naphthenic acids on the biomass accumulation of 21 potential phytoplankton remediation candidates.

    Woodworth, Adam P J; Frank, Richard A; McConkey, Brendan J; Müller, Kirsten M

    2012-12-01

    The oil sands of northern Alberta, Canada contain an estimated 170 billion barrels of crude oil. Extraction processes produce large amounts of liquid tailings known as oil sand process affected water (OSPW) that are toxic to aquatic organisms. Naphthenic acids (NAs), and their sodium salts, represent a significant contributor to the toxicity of these waters. Due to the recalcitrant nature of these compounds, an effective mode of remediation has yet to be established. This study investigates the suitability of the use of phytoplankton for remediation efforts based on two criteria: the ability of phytoplankton strains to withstand the toxic effects of NAs, and their rate of biomass accumulation. A total of 21 phytoplankton strains were isolated from waters containing NAs, cultured, and maintained under unialgal conditions. These strains were then exposed to NAs in concentrations ranging from 0mg L(-1) to 1000mg L(-1) over a 14 day period. Inhibition of growth was observed at 30mg L(-1) NA (one strain), 100mg L(-1) NA (one strain), 300mg L(-1) NA (six strains), and 1000mg L(-1) NA (six strains). Five strains failed to show any growth inhibition at any test concentration and two strains could not be analysed due to poor growth during the test period. Strains were then ranked based on their suitability for use in remediation efforts. PMID:23031586

  4. Accumulation of non-superoxide anion reactive oxygen species mediates nitrogen-limited alcoholic fermentation by Saccharomyces cerevisiae

    Ferreira, Ana Mendes; Marques, Belém Sampaio; Barbosa, Catarina; Rodrigues, Fernando José dos Santos; Costa, Vitor; Faia, A. Mendes; Ludovico, Paula; Leão, Cecília

    2010-01-01

    Throughout alcoholic fermentation, nitrogen depletion is one of the most important environmental stresses that can negatively affect the yeast metabolic activity and ultimately leads to fermentation arrest. Thus, the identification of the underlying effects and biomarkers of nitrogen limitation is valuable for controlling, and therefore optimizing, alcoholic fermentation. In this study, reactive oxygen species (ROS), plasma membrane integrity, and cell cycle were evaluated in a wine strain of...

  5. Random amino acid mutations and protein misfolding lead to Shannon limit in sequence-structure communication.

    Andreas Martin Lisewski

    Full Text Available The transmission of genomic information from coding sequence to protein structure during protein synthesis is subject to stochastic errors. To analyze transmission limits in the presence of spurious errors, Shannon's noisy channel theorem is applied to a communication channel between amino acid sequences and their structures established from a large-scale statistical analysis of protein atomic coordinates. While Shannon's theorem confirms that in close to native conformations information is transmitted with limited error probability, additional random errors in sequence (amino acid substitutions and in structure (structural defects trigger a decrease in communication capacity toward a Shannon limit at 0.010 bits per amino acid symbol at which communication breaks down. In several controls, simulated error rates above a critical threshold and models of unfolded structures always produce capacities below this limiting value. Thus an essential biological system can be realistically modeled as a digital communication channel that is (a sensitive to random errors and (b restricted by a Shannon error limit. This forms a novel basis for predictions consistent with observed rates of defective ribosomal products during protein synthesis, and with the estimated excess of mutual information in protein contact potentials.

  6. ABA biosynthesis defective mutants reduce some free amino acids accumulation under drought stress in tomato leaves in comparison with Arabidopsis plants tissues

    Adnan Ali Al.Asbahi

    2012-05-01

    Full Text Available The ability of plants to tolerate drought conditions is crucial for plant survival and crop production worldwide. The present data confirm previous findings reported existence of a strong relation between abscisic acid (ABA content and amino acid accumulation as response water stress which is one of the most important defense mechanism activated during water stress in many plant species. Therefore, free amino acids were measured to determine any changes in the metabolite pool in relation to ABA content. The ABA defective mutants of Arabidopsis plants were subjected to leaf dehydration for Arabidopsis on Whatman 3 mm filter paper at room temperature while, tomato mutant plants were subjected to drought stresses for tomato plants by withholding water. To understand the signal transduction mechanisms underlying osmotic stress-regulating gene induction and activation of osmoprotectant free amino acid synthesizing genes, we carried out a genetic screen to isolate Arabidopsis mutants defective in ABA biosynthesis under drought stress conditions. The present results revealed an accumulation of specific free amino acid in water stressed tissues in which majority of free amino acids are increased especially those playing an osmoprotectant role such as proline and glycine. Drought stress related Amino acids contents are significantly reduced in the mutants under water stress condition while they are increased significantly in the wild types plants. The exhibited higher accumulation of other amino acids under stressed condition in the mutant plants suggest that, their expressions are regulated in an ABA independent pathways. In addition, free amino acids content changes during water stress condition suggest their contribution in drought toleration as common compatible osmolytes.

  7. Enhanced Photosynthesis and Growth in atquac1 Knockout Mutants Are Due to Altered Organic Acid Accumulation and an Increase in Both Stomatal and Mesophyll Conductance.

    Medeiros, David B; Martins, Samuel C V; Cavalcanti, João Henrique F; Daloso, Danilo M; Martinoia, Enrico; Nunes-Nesi, Adriano; DaMatta, Fábio M; Fernie, Alisdair R; Araújo, Wagner L

    2016-01-01

    Stomata control the exchange of CO2 and water vapor in land plants. Thus, whereas a constant supply of CO2 is required to maintain adequate rates of photosynthesis, the accompanying water losses must be tightly regulated to prevent dehydration and undesired metabolic changes. Accordingly, the uptake or release of ions and metabolites from guard cells is necessary to achieve normal stomatal function. The AtQUAC1, an R-type anion channel responsible for the release of malate from guard cells, is essential for efficient stomatal closure. Here, we demonstrate that mutant plants lacking AtQUAC1 accumulated higher levels of malate and fumarate. These mutant plants not only display slower stomatal closure in response to increased CO2 concentration and dark but are also characterized by improved mesophyll conductance. These responses were accompanied by increases in both photosynthesis and respiration rates, without affecting the activity of photosynthetic and respiratory enzymes and the expression of other transporter genes in guard cells, which ultimately led to improved growth. Collectively, our results highlight that the transport of organic acids plays a key role in plant cell metabolism and demonstrate that AtQUAC1 reduce diffusive limitations to photosynthesis, which, at least partially, explain the observed increments in growth under well-watered conditions. PMID:26542441

  8. Successful high-level accumulation of fish oil omega-3 long-chain polyunsaturated fatty acids in a transgenic oilseed crop.

    Ruiz-Lopez, Noemi; Haslam, Richard P; Napier, Johnathan A; Sayanova, Olga

    2014-01-01

    Omega-3 (also called n-3) long-chain polyunsaturated fatty acids (≥C20; LC-PUFAs) are of considerable interest, based on clear evidence of dietary health benefits and the concurrent decline of global sources (fish oils). Generating alternative transgenic plant sources of omega-3 LC-PUFAs, i.e. eicosapentaenoic acid (20:5 n-3, EPA) and docosahexaenoic acid (22:6 n-3, DHA) has previously proved problematic. Here we describe a set of heterologous genes capable of efficiently directing synthesis of these fatty acids in the seed oil of the crop Camelina sativa, while simultaneously avoiding accumulation of undesirable intermediate fatty acids. We describe two iterations: RRes_EPA in which seeds contain EPA levels of up to 31% (mean 24%), and RRes_DHA, in which seeds accumulate up to 12% EPA and 14% DHA (mean 11% EPA and 8% DHA). These omega-3 LC-PUFA levels are equivalent to those in fish oils, and represent a sustainable, terrestrial source of these fatty acids. We also describe the distribution of these non-native fatty acids within C. sativa seed lipids, and consider these data in the context of our current understanding of acyl exchange during seed oil synthesis. PMID:24308505

  9. Does aspartic acid racemization constrain the depth limit of the subsurface biosphere?

    Onstott, T. C. [Princeton University; Aubrey, A.D. [Jet Propulsion Laboratory, Pasadena, CA; Kieft, T L [New Mexico Institute of Mining and Technology; Silver, B J [Jet Propulsion Laboratory, Pasadena, CA; Phelps, Tommy Joe [ORNL; Van Heerden, E. [University of the Free State; Opperman, D. J. [University of the Free State; Bada, J L. [Geosciences Research Division, Scripps Instition of Oceanography, Univesity of California San Diego,

    2014-01-01

    Previous studies of the subsurface biosphere have deduced average cellular doubling times of hundreds to thousands of years based upon geochemical models. We have directly constrained the in situ average cellular protein turnover or doubling times for metabolically active micro-organisms based on cellular amino acid abundances, D/L values of cellular aspartic acid, and the in vivo aspartic acid racemization rate. Application of this method to planktonic microbial communities collected from deep fractures in South Africa yielded maximum cellular amino acid turnover times of ~89 years for 1 km depth and 27 C and 1 2 years for 3 km depth and 54 C. The latter turnover times are much shorter than previously estimated cellular turnover times based upon geochemical arguments. The aspartic acid racemization rate at higher temperatures yields cellular protein doubling times that are consistent with the survival times of hyperthermophilic strains and predicts that at temperatures of 85 C, cells must replace proteins every couple of days to maintain enzymatic activity. Such a high maintenance requirement may be the principal limit on the abundance of living micro-organisms in the deep, hot subsurface biosphere, as well as a potential limit on their activity. The measurement of the D/L of aspartic acid in biological samples is a potentially powerful tool for deep, fractured continental and oceanic crustal settings where geochemical models of carbon turnover times are poorly constrained. Experimental observations on the racemization rates of aspartic acid in living thermophiles and hyperthermophiles could test this hypothesis. The development of corrections for cell wall peptides and spores will be required, however, to improve the accuracy of these estimates for environmental samples.

  10. Does aspartic acid racemization constrain the depth limit of the subsurface biosphere?

    Onstott, T C; Magnabosco, C; Aubrey, A D; Burton, A S; Dworkin, J P; Elsila, J E; Grunsfeld, S; Cao, B H; Hein, J E; Glavin, D P; Kieft, T L; Silver, B J; Phelps, T J; van Heerden, E; Opperman, D J; Bada, J L

    2014-01-01

    Previous studies of the subsurface biosphere have deduced average cellular doubling times of hundreds to thousands of years based upon geochemical models. We have directly constrained the in situ average cellular protein turnover or doubling times for metabolically active micro-organisms based on cellular amino acid abundances, D/L values of cellular aspartic acid, and the in vivo aspartic acid racemization rate. Application of this method to planktonic microbial communities collected from deep fractures in South Africa yielded maximum cellular amino acid turnover times of ~89 years for 1 km depth and 27 °C and 1-2 years for 3 km depth and 54 °C. The latter turnover times are much shorter than previously estimated cellular turnover times based upon geochemical arguments. The aspartic acid racemization rate at higher temperatures yields cellular protein doubling times that are consistent with the survival times of hyperthermophilic strains and predicts that at temperatures of 85 °C, cells must replace proteins every couple of days to maintain enzymatic activity. Such a high maintenance requirement may be the principal limit on the abundance of living micro-organisms in the deep, hot subsurface biosphere, as well as a potential limit on their activity. The measurement of the D/L of aspartic acid in biological samples is a potentially powerful tool for deep, fractured continental and oceanic crustal settings where geochemical models of carbon turnover times are poorly constrained. Experimental observations on the racemization rates of aspartic acid in living thermophiles and hyperthermophiles could test this hypothesis. The development of corrections for cell wall peptides and spores will be required, however, to improve the accuracy of these estimates for environmental samples. PMID:24289240

  11. Arbuscular mycorrhiza increase artemisinin accumulation in Artemisia annua by higher expression of key biosynthesis genes via enhanced jasmonic acid levels.

    Mandal, Shantanu; Upadhyay, Shivangi; Wajid, Saima; Ram, Mauji; Jain, Dharam Chand; Singh, Ved Pal; Abdin, Malik Zainul; Kapoor, Rupam

    2015-07-01

    It is becoming increasingly evident that the formation of arbuscular mycorrhiza (AM) enhances secondary metabolite production in shoots. Despite mounting evidence, relatively little is known about the underlying mechanisms. This study suggests that increase in artemisinin concentration in Artemisia annua colonized by Rhizophagus intraradices is due to altered trichome density as well as transcriptional patterns that are mediated via enhanced jasmonic acid (JA) levels. Mycorrhizal (M) plants had higher JA levels in leaf tissue that may be due to induction of an allene oxidase synthase gene (AOS), encoding one of the key enzymes for JA production. Non-mycorrhizal (NM) plants were exogenously supplied with a range of methyl jasmonic acid concentrations. When leaves of NM and M plants with similar levels of endogenous JA were compared, these matched closely in terms of shoot trichome density, artemisinin concentration, and transcript profile of artemisinin biosynthesis genes. Mycorrhization increased artemisinin levels by increasing glandular trichome density and transcriptional activation of artemisinin biosynthesis genes. Transcriptional analysis of some rate-limiting enzymes of mevalonate and methyl erythritol phosphate (MEP) pathways revealed that AM increases isoprenoids by induction of the MEP pathway. A decline in artemisinin concentration in shoots of NM and M plants treated with ibuprofen (an inhibitor of JA biosynthesis) further confirmed the implication of JA in the mechanism of artemisinin production. PMID:25366131

  12. Dissimilation of carbon monoxide to acetic acid by glucose-limited cultures of Clostridium thermoaceticum

    Clostridium thermoaceticum was cultivated in glucose-limited media, and the dissimilation of CO to acetic acid was evaluated. The authors found that cultures catalyzed the rapid dissimilation of CO to acetic acid and CO2, with the stoichiometry obtained for conversion approximating that predicted from the following reaction: 4CO + 2H2O → CH3CO2H + 2CO2. Growing cultures formed approximately 50 mmol (3 g) of CO-derived acetic acid per liter of culture, with the rate of maximal consumption approximating 9.1 mmol of CO consumed/h per liter of culture. In contrast, resting cells were found not to dissimilate CO to acetic acid. 14CO was incorporated, with equal distribution between the carboxyl and methyl carbons of acetic acid when the initial cultivation gas phase was 100% CO whereas 14CO2 preferentially entered the carboxyl carbon when the initial gas phase was 100% CO2. Significantly, in the presence of saturating levels of CO, 14CO2 preferentially entered the methyl carbon, whereas saturating levels of CO2 yielded 14CO-derived labeling predominantly in the carboxyl carbon. These findings are discussed in relation to the path of carbon flow to acetic acid

  13. Accumulation of cellobiose lipids under nitrogen-limiting conditions by two ustilaginomycetous yeasts, Pseudozyma aphidis and Pseudozyma hubeiensis.

    Morita, Tomotake; Fukuoka, Tokuma; Imura, Tomohiro; Kitamoto, Dai

    2013-02-01

    Some basidiomycetous yeast strains extracellularly produce cellobiose lipids (CLs), glycolipid biosurfactants which have strong fungicidal activity. The representative CL producer Ustilago maydis produces CLs together with the other glycolipids, mannosylerythritol lipids (MELs); the preference of the two glycolipids is affected considerably by the nitrogen source. To develop new CL producers, 12 MEL producers were cultured under the nitrogen-limited conditions. Pseudozyma aphidis and Pseudozyma. hubeiensis were characterized as new CL producers. CL production was induced on three strains, P. aphidis, Pseudozyma graminicola, and P. hubeiensis under these conditions. The putative homologous genes of U. maydis cyp1, which encodes a P450 monooxygenase, essential for CL biosynthesis, were partially amplified from their genomic DNA. The nucleotide sequences of the gene fragments from P. hubeiensis and P. aphidis shared identities with U. maydis cyp1 of 99% and 78%, respectively. Furthermore, all of the deduced translation products are tightly clustered in the phylogenic tree of the monooxygenase. These results suggest that the genes involved with CL biosynthesis must be widely distributed in the basidiomycetous fungi as well as the MEL biosynthesis genes, and thus, the genus Pseudozyma has great potential as a biosurfactant producer. PMID:22985214

  14. Different responses of two Mosla species to potassium limitation in relation to acid rain deposition

    Meng WANG; Bao-jing GU; Ying GE; Zhen LIU; De-an JIANG; Scott X. CHANG; Jie CHANG

    2009-01-01

    The increasingly serious problem of acid rain is leading to increased potassium (K) loss from soils, and in our field investigation, we found that even congenerically relative Mosla species show different tolerance to K-deficiency. A hydroponic study was conducted on the growth of two Mosla species and their morphological, physiological and stoichiometric traits in response to limited (0.35 mmol K/L), normal (3.25 mmol K/L) and excessive (6.50 mmol K/L) K concentrations. Mosla hang-chowensis is an endangered plant, whereas Mosla dianthera a widespread weed. In the case of M. hangchowensis, in comparison with normal K concentration, K-limitation induced a significant reduction in net photosynthetic rate (Pn), soluble protein content, and superoxide dismutase (SOD) activity, but an increase in malondialdehyde (MDA) concentration. However, leaf mass ratio (LMR) and root mass ratio (RMR) were changed little by K-limitation. In contrast, for M. dianthera, K-limitation had little effect on Pn, soluble protein content, SOD activity, and MDA concentration, but increased LMR and RMR. Critical values of N (nitrogen):K and K:P (phosphorus) ratios in the shoots indicated that limitation in acquiring K occurred under K-limited conditions for M. hangchowensis but not for M. dianthera. We found that low K content in natural habitats was a restrictive factor in the growth and distribution of M. hangchowensis, and soil K-deficiency caused by acid rain worsened the situation of M. hangchowensis, while M. dianthera could well acclimate to the increasing K-deficiency. We suggest that controlling the acid rain and applying K fertilizers may be an effective way to rescue the endangered M. hangchowensis.

  15. The Na+ transporter, TaHKT1;5-D, limits shoot Na+ accumulation in bread wheat

    Byrt, Caitlin Siobhan

    2014-10-01

    Bread wheat (Triticum aestivum L.) has a major salt tolerance locus, Kna1, responsible for the maintenance of a high cytosolic K+/Na+ ratio in the leaves of salt stressed plants. The Kna1 locus encompasses a large DNA fragment, the distal 14% of chromosome 4DL. Limited recombination has been observed at this locus making it difficult to map genetically and identify the causal gene. Here, we decipher the function of TaHKT1;5-D, a candidate gene underlying the Kna1 locus. Transport studies using the heterologous expression systems Saccharomyces cerevisiae and Xenopus laevis oocytes indicated that TaHKT1;5-D is a Na+-selective transporter. Transient expression in Arabidopsis thaliana mesophyll protoplasts and in situ polymerase chain reaction indicated that TaHKT1;5-D is localised on the plasma membrane in the wheat root stele. RNA interference-induced silencing decreased the expression of TaHKT1;5-D in transgenic bread wheat lines which led to an increase in the Na+ concentration in the leaves. This indicates that TaHKT1;5-D retrieves Na+ from the xylem vessels in the root and has an important role in restricting the transport of Na+ from the root to the leaves in bread wheat. Thus, TaHKT1;5-D confers the essential salinity tolerance mechanism in bread wheat associated with the Kna1 locus via shoot Na+ exclusion and is critical in maintaining a high K+/Na+ ratio in the leaves. These findings show there is potential to increase the salinity tolerance of bread wheat by manipulation of HKT1;5 genes.

  16. Accumulation of nitrogen - a critical parameter for the calculation of load limits from nitrogen in forests; Akkumulering av nitrogen - en kritisk parameter for beregning av taalegrenser for nitrogen i skog

    Sogn, T.A.; Stuanes, A.O.; Abrahamsen, G.

    1996-01-01

    The conference paper deals with the accumulation of nitrogen in forests in Norway. The level of accumulation is a critical factor for the calculation of load limits. The paper compares the average rapidity values of accumulation since the last glacial age with the calculated values from the more short-lasting period based on data from surveying programs of the State Pollution Control Authority, manuring experiments, and other relevant research programs in this field. 8 refs., 1 fig., 1 tab.

  17. Yeast Extract and Silver Nitrate Induce the Expression of Phenylpropanoid Biosynthetic Genes and Induce the Accumulation of Rosmarinic Acid in Agastache rugosa Cell Culture

    Woo Tae Park

    2016-03-01

    Full Text Available The present study aimed to investigate the role of yeast extract and silver nitrate on the enhancement of phenylpropanoid pathway genes and accumulation of rosmarinic acid in Agastache rugosa cell cultures. The treatment of cell cultures with yeast extract (500 mg/L and silver nitrate (30 mg/L for varying times enhanced the expression of genes in the phenylpropanoid pathway and the production of rosmarinic acid. The results indicated that the expression of RAS and HPPR was proportional to the amount of yeast extract and silver nitrate. The transcript levels of HPPR under yeast extract treatment were 1.84-, 1.97-, and 2.86-fold higher than the control treatments after 3, 6, and 12 h, respectively, whereas PAL expression under silver nitrate treatment was 52.31-fold higher than in the non-treated controls after 24 h of elicitation. The concentration of rosmarinic acid was directly proportional to the concentration of the applied elicitors. Yeast extract supplementation documented the highest amount of rosmarinic acid at 4.98 mg/g, whereas silver nitrate addition resulted in a comparatively lower amount of rosmarinic acid at 0.65 mg/g. In conclusion, addition of yeast extract to the cell cultures enhanced the accumulation of rosmarinic acid, which was evidenced by the expression levels of the phenylpropanoid biosynthetic pathway genes in A. rugosa.

  18. Nucleic acids for recognition and catalysis: landmarks, limitations, and looking to the future.

    Perrin, D M

    2000-06-01

    Combinatorial selection of nucleic acids has led to the discovery of novel ligands and catalysts that have implications for both chemistry and medicine. In the context of combinatorial chemistry, degenerate syntheses of nucleic acid libraries readily generate as many as 10(15) different molecules in which a small percentage exhibit interesting binding and/or catalytic properties. The primary advantage of nucleic acids is that library coding is an intrinsic property; sequential composition directly determines the activity. At low temperatures, the sequential composition of single stranded nucleic acids governs folding into irregular tertiary structures resulting in interesting activities. At higher temperatures, the same structures are unfolded and decoded by polymerases to reveal sequential information. The use of PCR (polymerase chain reaction) permits amplification and thus enrichment of the selected activity which is then regenerated chemi-enzymatically. Iterative selection and amplification result in one of the highest throughput screens conceivable whereby each molecule encodes its own activity permitting the ultimate in parallel sampling. Finally, sequence information, and by extension the chemical composition, is obtained by simple sequencing techniques obviating the need for mass spectrometric deconvolution, parallel tagging, and/or large volumes needed for viral and cell culture. This review begins with an introduction of general concepts and considerations. The potential for nucleic acids to generate tight-binding ligands is of interest to structural biologists and medicinal chemists. The therapeutic implications to medicine are also touched upon. Since combinatorially selected nucleic acids and antibodies share many conceptual similarities, their respective advantages and limitations are compared. Theoretical and practical limitations for catalyst discovery are discussed along with the use of other chemical and physical approaches to address some current

  19. The effect of methyl jasmonate and phenolic acids on growth of seedlings and accumulation of anthocyanins in common buckwheat (Fagopyrum esculentum Moench

    Marcin Horbowicz

    2012-12-01

    Full Text Available The effect of methyl jasmonate (JA-Me and phenolic acids: trans-cinnamic acid (t-CA, p-coumaric acid (p-CA, salicylic acid (SA as well as naringenine (NAR on growth of seedlings and accumulation of anthocyanins in common buckwheat (Fagopyrum esculentum Moench were studied. JA-Me and phenolics were applied to growth medium of 4-days etiolated buckwheat seedlings before their exposition to day/night (16h/8h conditions. The increase of primary roots and hypocotyls length were measured after 3 days of seedling growth in such conditions. At the end of experiment the total anthocyanins contents were measured as well. Methyl jasmonate (JA-Me and trans-cinnamic acid (t-CA inhibited growth of the primary root in young buckwheat seedlings, while naringenine (NAR had a stimulatory influence, and p-coumaric acid had no effect at all. None of investigated phenolics or JA-Me had an effect on the growth of buckwheat hypocotyls, except the mixture of JA-Me and p-coumarcic acid. JA-Me significantly decreased the anthocyanins level in buckwheat hypocototyls, but not in cotyledons. trans-Cinnamic acid, p-coumaric acid and naringenine had no significant influence on the anthocyanin level in hypocotyls and cotyledons of buckwheat seedlings. Simultaneous treatment of buckwheat seedlings with JA-Me and t-CA or p-CA did not change the inhibition of anthocyanins accumulation in buckwheat hypocotyls by JA-Me. In the hypocotyls of buckwheat treated with a mixture of JA-Me and NAR, or SA, a synergistic reduction of anthocyanins was observed.

  20. Achieving Stable Nitritation for Mainstream Deammonification by Combining Free Nitrous Acid-Based Sludge Treatment and Oxygen Limitation

    Wang, Dongbo; Wang, Qilin; Laloo, Andrew; Xu, Yifeng; Bond, Philip L.; Yuan, Zhiguo

    2016-05-01

    Stable nitritation is a critical bottleneck for achieving autotrophic nitrogen removal using the energy-saving mainstream deammonification process. Herein we report a new strategy to wash out both the Nitrospira sp. and Nitrobacter sp. from the treatment of domestic-strength wastewater. The strategy combines sludge treatment using free nitrous acid (FNA) with dissolved oxygen (DO) control in the nitritation reactor. Initially, the nitrifying reactor achieved full conversion of NH4+ to NO3‑. Then, nitrite accumulation at ~60% was achieved in the reactor when 1/4 of the sludge was treated daily with FNA at 1.82 mg N/L in a side-stream unit for 24 h. Fluorescence in-situ hybridization (FISH) revealed FNA treatment substantially reduced the abundance of nitrite oxidizing bacteria (NOB) (from 23.0 ± 4.3 to 5.3 ± 1.9%), especially that of Nitrospira sp. (from 15.7 ± 3.9 to 0.4 ± 0.1%). Nitrite accumulation increased to ~80% when the DO concentration in the mainstream reactor was reduced from 2.5–3.0 to 0.3–0.8 mg/L. FISH revealed the DO limitation further reduced the abundance of NOB (to 2.1 ± 1.0%), especially that of Nitrobacter sp. (from 4.9 ± 1.2 to 1.8 ± 0.8%). The strategy developed removes a major barrier for deammonification in low-strength domestic wastewater.

  1. Dietary supplementation with phytosterol and ascorbic acid reduces body mass accumulation and alters food transit time in a diet-induced obesity mouse model

    Kozlowski Petri

    2011-06-01

    Full Text Available Abstract Previous research indicates that animals fed a high fat (HF diet supplemented with disodium ascorbyl phytostanyl phosphate (DAPP exhibit reduced mass accumulation when compared to HF control. This compound is a water-soluble phytostanol ester and consists of a hydrophobic plant stanol covalently bonded to ascorbic acid (Vitamin C. To provide insight into the mechanism of this response, we examined the in vivo effects of a high fat diet supplemented with ascorbic acid (AA in the presence and absence of unesterified phytosterols (PS, and set out to establish whether the supplements have a synergistic effect in a diet-induced obesity mouse model. Our data indicate that HF diet supplementation with a combination of 1% w/w phytosterol and 1% w/w ascorbic acid results in reduced mass accumulation, with mean differences in absolute mass between PSAA and HF control of 10.05%; and differences in mass accumulation of 21.6% (i.e. the PSAA group gained on average 21% less mass each week from weeks 7-12 than the HF control group. In our previous study, the absolute mass difference between the 2% DAPP and HF control was 41%, while the mean difference in mass accumulation between the two groups for weeks 7-12 was 67.9%. Mass loss was not observed in animals supplemented with PS or AA alone. These data suggest that the supplements are synergistic with respect to mass accumulation, and the esterification of the compounds further potentiates the response. Our data also indicate that chronic administration of PS, both in the presence and absence of AA, results in changes to fecal output and food transit time, providing insight into the possibility of long-term changes in intestinal function related to PS supplementation.

  2. Characterization of major ripening events during softening in grape: turgor, sugar accumulation, abscisic acid metabolism, colour development, and their relationship with growth.

    Castellarin, Simone D; Gambetta, Gregory A; Wada, Hiroshi; Krasnow, Mark N; Cramer, Grant R; Peterlunger, Enrico; Shackel, Kenneth A; Matthews, Mark A

    2016-02-01

    Along with sugar accumulation and colour development, softening is an important physiological change during the onset of ripening in fruits. In this work, we investigated the relationships among major events during softening in grape (Vitis vinifera L.) by quantifying elasticity in individual berries. In addition, we delayed softening and inhibited sugar accumulation using a mechanical growth-preventing treatment in order to identify processes that are sugar and/or growth dependent. Ripening processes commenced on various days after anthesis, but always at similarly low elasticity and turgor. Much of the softening occurred in the absence of other changes in berry physiology investigated here. Several genes encoding key cell wall-modifying enzymes were not up-regulated until softening was largely completed, suggesting softening may result primarily from decreases in turgor. Similarly, there was no decrease in solute potential, increase in sugar concentration, or colour development until elasticity and turgor were near minimum values, and these processes were inhibited when berry growth was prevented. Increases in abscisic acid occurred early during softening and in the absence of significant expression of the V. vinifera 9-cis-epoxycarotenoid dioxygenases. However, these increases were coincident with decreases in the abscisic acid catabolite diphasic acid, indicating that initial increases in abscisic acid may result from decreases in catabolism and/or exogenous import. These data suggest that softening, decreases in turgor, and increases in abscisic acid represent some of the earliest events during the onset of ripening. Later, physical growth, further increases in abscisic acid, and the accumulation of sugar are integral for colour development. PMID:26590311

  3. Limiting amino acids in an 11% crude protein corn-soybean meal diet for growing pigs.

    Russell, L E; Kerr, B J; Easter, R A

    1987-11-01

    Three experiments were conducted to test the hypothesis that methionine, isoleucine, valine or nitrogen either singly or in combination are limiting in an 11% crude protein, lysine-tryptophan-threonine-supplemented, corn-soybean meal diet for growing pigs. A 16% crude protein diet was used as a positive control in each experiment and all amino acid additions were made, at a minimum, to equal requirements. Average initial weights were 21.3 kg, 23.0 kg and 19.1 kg in Exp. 1, 2 and 3, respectively. The experiments averaged 4 wk in duration. In Exp. 1 and 2, neither the addition of glutamic acid as a source of nitrogen, nor methionine to the 11% diet resulted in any improvement (P greater than .20) in rate or efficiency of growth. Addition of the combination of isoleucine and valine to the 11% diet resulted in an increase (P less than .05) in both growth rate and feed efficiency to a level not different (P greater than .20) from that of the pigs consuming the positive control diet. The addition of valine to the 11% crude protein diet with supplemental lysine, tryptophan and threonine (Exp. 3) caused an improvement in daily gain (P less than .05) but not feed efficiency (P greater than .10). Isoleucine addition tended to reduce pig performance. The results of these experiments suggest that an 11% crude protein, corn-soybean meal diet fortified with lysine, tryptophan and threonine is not limiting in sulfur amino acids or nitrogen. Valine may be the only limiting amino acid. PMID:3693151

  4. Suppression of γ-Aminobutyric Acid (GABA) Transaminases Induces Prominent GABA Accumulation, Dwarfism and Infertility in the Tomato (Solanum lycopersicum L.)

    Koike, Satoshi; Matsukura, Chiaki; Takayama, Mariko; Asamizu, Erika; Ezura, Hiroshi

    2013-01-01

    Tomatoes accumulate γ-aminobutyric acid (GABA) at high levels in the immature fruits. GABA is rapidly converted to succinate during fruit ripening through the activities of GABA transaminase (GABA-T) and succinate semialdehyde dehydrogenase (SSADH). Although three genes encoding GABA-T and both pyruvate- and α-ketoglutarate-dependent GABA-T activities have been detected in tomato fruits, the mechanism underlying the GABA-T-mediated conversion of GABA has not been fully understood. In this wor...

  5. Perfluoroalkyl Acids (PFAAs) and Selected Precursors in the Baltic Sea Environment: Do Precursors Play a Role in Food Web Accumulation of PFAAs?

    Gebbink, Wouter A; Bignert, Anders; Berger, Urs

    2016-06-21

    The present study examined the presence of perfluoroalkyl acids (PFAAs) and selected precursors in the Baltic Sea abiotic environment and guillemot food web, and investigated the relative importance of precursors in food web accumulation of PFAAs. Sediment, water, zooplankton, herring, sprat, and guillemot eggs were analyzed for perfluoroalkane sulfonic acids (PFSAs; C4,6,8,10) and perfluoroalkyl carboxylic acids (PFCAs; C6-15) along with six perfluoro-octane sulfonic acid (PFOS) precursors and 11 polyfluoroalkyl phosphoric acid diesters (diPAPs). FOSA, FOSAA and its methyl and ethyl derivatives (Me- and EtFOSAA), and 6:2/6:2 diPAP were detected in sediment and water. While FOSA and the three FOSAAs were detected in all biota, a total of nine diPAPs were only detected in zooplankton. Concentrations of PFOS precursors and diPAPs exceeded PFOS and PFCA concentrations, respectively, in zooplankton, but not in fish and guillemot eggs. Although PFOS precursors were present at all trophic levels, they appear to play a minor role in food web accumulation of PFOS based on PFOS precursor/PFOS ratios and PFOS and FOSA isomer patterns. The PFCA pattern in fish could not be explained by the intake pattern based on PFCAs and analyzed precursors, that is, diPAPs. Exposure to additional precursors might therefore be a dominant exposure pathway compared to direct PFCA exposure for fish. PMID:27192404

  6. Naturally evolved enhanced Cd tolerance of Dianthus carthusianorum L. is not related to accumulation of thiol peptides and organic acids

    Wójcik, Małgorzata; DRESLER, Sławomir; Plak, Andrzej; Tukiendorf, Anna

    2014-01-01

    Two contrasting ecotypes of Dianthus carthusianorum L., metallicolous (M) and nonmetallicolous (NM), were cultivated in hydroponics at 0–50 μM Cd for 14 days to compare their Cd accumulation, sensitivity and tolerance mechanisms. While both ecotypes contained similar concentrations of Cd in the shoots and roots, the M ecotype was more Cd-tolerant (as measured by fresh weight production and root and leaf viability). Both ecotypes accumulated phytochelatins (PCs) in response to Cd with a higher...

  7. Accumulated SET protein up-regulates and interacts with hnRNPK, increasing its binding to nucleic acids, the Bcl-xS repression, and cellular proliferation

    Almeida, Luciana O.; Garcia, Cristiana B.; Matos-Silva, Flavia A. [Department of Clinical Analyses, Toxicology and Food Sciences, School of Pharmaceutical Sciences of Ribeirão Preto, University of São Paulo, Ribeirão Preto, SP (Brazil); Curti, Carlos [Department of Physics and Chemistry, School of Pharmaceutical Sciences of Ribeirão Preto, University of São Paulo, Ribeirão Preto, SP (Brazil); Leopoldino, Andréia M., E-mail: andreiaml@usp.br [Department of Clinical Analyses, Toxicology and Food Sciences, School of Pharmaceutical Sciences of Ribeirão Preto, University of São Paulo, Ribeirão Preto, SP (Brazil)

    2014-02-28

    Highlights: • hnRNPK is a new target of SET. • SET regulates hnRNPK. • SET and hnRNPK accumulation promotes tumorigenesis. • SET accumulation is a potential model to study genes regulated by SET-hnRNPK. - Abstract: SET and hnRNPK are proteins involved in gene expression and regulation of cellular signaling. We previously demonstrated that SET accumulates in head and neck squamous cell carcinoma (HNSCC); hnRNPK is a prognostic marker in cancer. Here, we postulate that SET and hnRNPK proteins interact to promote tumorigenesis. We performed studies in HEK293 and HNSCC (HN6, HN12, and HN13) cell lines with SET/hnRNPK overexpression and knockdown, respectively. We found that SET and/or hnRNPK protein accumulation increased cellular proliferation. SET accumulation up-regulated hnRNPK mRNA and total/phosphorylated protein, promoted hnRNPK nuclear location, and reduced Bcl-x mRNA levels. SET protein directly interacted with hnRNPK, increasing both its binding to nucleic acids and Bcl-xS repression. We propose that hnRNPK should be a new target of SET and that SET–hnRNPK interaction, in turn, has potential implications in cell survival and malignant transformation.

  8. Crossing the pedogenetic threshold: Apparent phosphorus limitation by soil microorganisms in unglaciated acidic eastern hardwood forests

    Deforest, J. L.; Smemo, K. A.; Burke, D. J.

    2010-12-01

    The availability of soil phosphorus (P) can significantly influence microbial community composition and the ecosystem-level processes they mediate. However, the threshold at which soil microorganisms become functionally P-limited is unclear because of soil acidity effect on P availability. We reason that acidic temperate hardwood forest ecosystems are, in fact, functionally P-limited, but compensation occur via soil microbial production of phosphatase enzymes. We tested this hypothesis in glaciated and unglaciated mature mixed-mesophytic forests in eastern Ohio where both soil pH and P availability had been experientially manipulated. We measured the activity of two P acquiring soil enzymes, phosphomonoesterase (PMono) and phosphodiesterase (PDi), to understand how soil acidity and available P influence microbial function. Our experimental treatments elevated ambient soil pH from below 4.5 to around 5.5 and increased readily available phosphate from 3 to ~25 mg P/kg on glaciated soils and from 0.5 to ~5 mg P/kg on unglaciated soils. The P treatment decreased the activity of PDi by 82% relative to the control on unglaciated soils, but we observed no P treatment effect on glaciated soils. A similar result was observed for PMono. Soil pH, alone, did not significantly influence enzyme activities. Results suggest that soil microorganisms are more likely to be P-limited in older unglaciated soils. However, dramatically higher phosphatase activity in response to very low P availability suggests that an underlying ecosystem P limitation can be ameliorated by soil microbial community dynamics. This mechanism may be more important for older, unglaciated soils that have already crossed a pedogenic threshold where P availability influences ecosystem and microbial function.

  9. Anthocyanins and phenolic acids from a wild blueberry (Vaccinium angustifolium) powder counteract lipid accumulation in THP-1-derived macrophages

    Del Bo', Cristian; Cao, Yi; Roursgaard, Martin;

    2016-01-01

    PURPOSE: Blueberries are a rich source of anthocyanins (ACNs) and phenolic acids (PA), which are hypothesized to protect against development of atherosclerosis. The present study examined the effect of an ACN- and PA-rich fractions, obtained from a wild blueberry powder, on the capacity to counte....... CONCLUSIONS: The results demonstrated a potential role of both the ACN- and PA-rich fractions and single compounds in the lipid accumulation also at concentrations close to that achievable in vivo.......PURPOSE: Blueberries are a rich source of anthocyanins (ACNs) and phenolic acids (PA), which are hypothesized to protect against development of atherosclerosis. The present study examined the effect of an ACN- and PA-rich fractions, obtained from a wild blueberry powder, on the capacity to...... concentrations (from 0.05 to 10 μg mL(-1)) of ACN- and PA-rich fractions, pure ACN standards (malvidin, delphinidin and cyanidin 3-glucoside), and metabolites (syringic, gallic and protocatechuic acids). Lipid accumulation was quantified with the fluorescent dye Nile red. RESULTS: Lipid accumulation was reduced...

  10. Ability of Agrogyron elongatum to accumulate the single metal of cadmium, copper, nickel and lead and root exudation of organic acids

    2001-01-01

    Agrogyron elongatum were grown in nutrient solution containing moderate to high amounts of separate heavy metal of Cd, Cu, Ni and Pb in a greenhouse for a 9-day. Cd, Cu, Ni and Pb generally led to decrease in the elongation of roots although the length of seedlings exposed to Cd and Pb at 0,05 and 0.5 mg/L showed to be slightly greater than that of controls. Of the four metals in the experiment, Pb was absorbed and accumulated to the highest level, with the concentrations of 92754 mg/kg dry weight (DW) in roots and 11683 mg/kg DW in shoots. Cd was moderately accumulated in Agrogyron elongatum, but the maximum bioaccumulation coefficients (BCs) for rpots and shoots were observed. The patterns for Cu and Ni uptake and distribution in plants differed from those of Pb and Cd, as it was showed that the shoot accumulation of Cu and Ni was significantly higher than in roots. A. elongatum had the highest Ni concentration in shoots (30261 mg/kg DW)at the external concentration of 250 mg/L. Cu ranked second, with a shoot concentration of 12230 mg/kg DW when 50 mg/L Cu in solution was applied. For the four trace elements tested, the highest concentrations in shoots decreased by the order of Ni > Cu > Pb > Cd (mg/kg DW),and those in roots were Pb > Cd > Ni > Cu (mg/kg DW). Malic, oxalic and citric acids exuded by roots exposed to 1 and 50 mg/L of the metals were detected. Release of organic acids from plants significantly differed among the metal treatments. Cu was most effectively in inducing rpot exudation of the three types of organic acids. Cd, and Ni were also the inducers of secretion of malic and oxalic acids. With reference of Pb,a small amounts of malic and oxalic acids were detected in the root exudates, but few quantities of citric acid were found. However, no orrelation between alternations in root exudation of organic acids and metal accumulation could be established.

  11. Predator evasion in zooplankton is suppressed by polyunsaturated fatty acid limitation.

    Brzeziński, Tomasz; von Elert, Eric

    2015-11-01

    Herbivorous zooplankton avoid size-selective predation by vertical migration to a deep, cold water refuge. Adaptation to low temperatures in planktonic poikilotherms depends on essential dietary lipids; the availability of these lipids often limits growth and reproduction of zooplankton. We hypothesized that limitation by essential lipids may affect habitat preferences and predator avoidance behavior in planktonic poikilotherms. We used a liposome supplementation technique to enrich the green alga Scenedesmus obliquus and the cyanobacterium Synecchococcus elongatus with the essential lipids, cholesterol and eicosapentaenoic acid (EPA), and an indoor system with a stratified water-column (plankton organ) to test whether the absence of these selected dietary lipids constrains predator avoidance (habitat preferences) in four species of the key-stone pelagic freshwater grazer Daphnia. We found that the capability of avoiding fish predation through habitat shift to the deeper and colder environment was suppressed in Daphnia unless the diet was supplemented with EPA; however, the availability of cholesterol did not affect habitat preferences of the tested taxa. Thus, their ability to access a predator-free refuge and the outcome of predator-prey interactions depends upon food quality (i.e. the availability of an essential fatty acid). Our results suggest that biochemical food quality limitation, a bottom-up factor, may affect the top-down control of herbivorous zooplankton. PMID:26232092

  12. Limitations to ruminal absorption of volatile fatty acids in lactating dairy cows

    Storm, Adam Christian

    ruminal overproduction of VFA represents a possible health risk. A challenge of the lactating dairy cow is to avoid acidic overload of the rumen while satisfying the nutritional demand of the peripheral tissue. Thus, the overall objective of the Ph.D. study was to detect and quantify possible limitations......The symbiotic relationship between ruminants and the microbial inhabitants of the rumen constitutes a unique feature of the ruminant digestive system. Through the microbial utilization of feed carbohydrates and protein in the rumen, substantial amounts of fermentation products and microbial cell...... bodies are released for the benefit of the host animal. The main end product of ruminal fermentation is volatile fatty acids (VFA), which provide the cow with the majority of energetic precursors for metabolic processes. Ruminal VFA are therefore, quantitatively the most important nutrient in cattle, but...

  13. Effects of Limiting Amino Acids on Rumen Fermentation and Microbial Community In vitro

    2008-01-01

    Three goats fitted with cannula were used to provide rumen liquor to investigate the effects of limiting amino acids on rumen fermentation and microbial community in vitro. The removal method was used in the current experiments. Treatments are total essential amino acid (TEAA), His-removal, Lys-removal, Met-removal, and branch chain amino acid (BCAA)-removal. Results indicated that, pH-value ranged between 5.9 and 6.8, with the highest mean value for the group with BCAA-removal (6.54) in the culture. Concentration of NH3-N ranged between 10.99 to 30.51 mg 100 mL-1, with the group of TEAA recording the highest average NH3-N concentration (17.85 mg 100 mL-1). Yields of microbial protein and limiting degree on microbial growth varied with treatments (P < 0.01), and the lowest accrued in treatment with BCAA-removal (0.1389, 0.1772, and 0.3161 mg mL-1 for bacteria, protozoa, and mixed microbes, respectively), compared to the group with TEAA, microbial production of mixed microbes decreased by 44.52%. As for micro-flora, protozoa to bacteria ratio was the lowe st for the group with Lys-removal (89.12%), while the h i ghe st for the group with B CAA-removal (127.60%) (P < 0.01). Furthermore, PCR-SSCP analysis revealed that, microbial profile subjected to substrates within bacteria and protozoa groups. It was therefore concluded that, dietary amino acid influenced both rumen fermentation and microbial characteristics.

  14. The Unusual Acid-Accumulating Behavior during Ripening of Cherimoya (Annona cherimola Mill.) is Linked to Changes in Transcription and Enzyme Activity Related to Citric and Malic Acid Metabolism.

    González-Agüero, Mauricio; Tejerina Pardo, Luis; Zamudio, María Sofía; Contreras, Carolina; Undurraga, Pedro; Defilippi, Bruno G

    2016-01-01

    Cherimoya (Annona cherimola Mill.) is a subtropical fruit characterized by a significant increase in organic acid levels during ripening, making it an interesting model for studying the relationship between acidity and fruit flavor. In this work, we focused on understanding the balance between the concentration of organic acids and the gene expression and activity of enzymes involved in the synthesis and degradation of these metabolites during the development and ripening of cherimoya cv. "Concha Lisa". Our results showed an early accumulation of citric acid and other changes associated with the accumulation of transcripts encoding citrate catabolism enzymes. During ripening, a 2-fold increase in malic acid and a 6-fold increase in citric acid were detected. By comparing the contents of these compounds with gene expression and enzymatic activity levels, we determined that cytoplasmic NAD-dependent malate dehydrogenase (cyNAD-MDH) and mitochondrial citrate synthase (mCS) play important regulatory roles in the malic and citric acid biosynthetic pathways. PMID:27120592

  15. Accumulation of 3-hydroxytetradecenoic acid: Cause or corollary of glucolipotoxic impairment of pancreatic β-cell bioenergetics?

    Nicolai M. Doliba

    2015-12-01

    Conclusions: As long chain 3-hydroxylated FA metabolites are known to uncouple heart and brain mitochondria [53–55], we propose that under glucolipotoxic condition, unsaturated hydroxylated long-chain FAs accumulate, uncouple and ultimately inhibit β-cell respiration. This leads to the slow deterioration of mitochondrial function progressing to bioenergetics β-cell failure.

  16. The potato suberin feruloyl transferase FHT which accumulates in the phellogen is induced by wounding and regulated by abscisic and salicylic acids.

    Boher, Pau; Serra, Olga; Soler, Marçal; Molinas, Marisa; Figueras, Mercè

    2013-08-01

    The present study provides new insights on the role of the potato (Solanum tuberosum) suberin feruloyl transferase FHT in native and wound tissues, leading to conclusions about hitherto unknown properties of the phellogen. In agreement with the enzymatic role of FHT, it is shown that its transcriptional activation and protein accumulation are specific to tissues that undergo suberization such as the root boundary layers of the exodermis and the endodermis, along with the tuber periderm. Remarkably, FHT expression and protein accumulation within the periderm is restricted to the phellogen derivative cells with phellem identity. FHT levels in the periderm are at their peak near harvest during periderm maturation, with the phellogen becoming meristematically inactive and declining thereafter. However, periderm FHT levels remain high for several months after harvest, suggesting that the inactive phellogen retains the capacity to synthesize ferulate esters. Tissue wounding induces FHT expression and the protein accumulates from the first stages of the healing process onwards. FHT is up-regulated by abscisic acid and down-regulated by salicylic acid, emphasizing the complex regulation of suberin synthesis and wound healing. These findings open up new prospects important for the clarification of the suberization process and yield important information with regard to the skin quality of potatoes. PMID:23918964

  17. Tailoring Conformation-Induced Chromism of Polythiophene Copolymers for Nucleic Acid Assay at Resource Limited Settings.

    Rajwar, Deepa; Ammanath, Gopal; Cheema, Jamal Ahmed; Palaniappan, Alagappan; Yildiz, Umit Hakan; Liedberg, Bo

    2016-04-01

    Here we report on the design and synthesis of cationic water-soluble thiophene copolymers as reporters for colorimetric detection of microRNA (miRNA) in human plasma. Poly(3-alkoxythiophene) (PT) polyelectrolytes with controlled ratios of pendant groups such as triethylamine/1-methyl imidazole were synthesized for optimizing interaction with target miRNA sequence (Tseq). Incorporation of specific peptide nucleic acid (PNA) sequences with the cationic polythiophenes yielded distinguishable responses upon formation of fluorescent PT-PNA-Tseq triplex and weakly fluorescent PT-Tseq duplex, thereby enabling selective detection of target miRNA. Unlike homopolymers of PT (hPT), experimental results indicate the possibility of utilizing copolymers of PT (cPT) with appropriate ratios of pendant groups for miRNA assay in complex matrices such as plasma. As an illustration, colorimetric responses were obtained for lung cancer associated miRNA sequence (mir21) in human plasma, with a detection limit of 10 nM, illustrating the feasibility of proposed methodology for clinical applications without involving sophisticated instrumentation. The described methodology therefore possesses high potential for low-cost nucleic acid assays in resource-limited settings. PMID:26956217

  18. Effect of Soil Moisture on Release of Low-MolecularWeight Organic Acids in Root Exudates and the Accumulation of Iron in Root Apoplasm of Peanut

    2000-01-01

    A three-compartments rhizobox was designed and used to study the low-molecular-weight organic acids in root exudates and the root apoplastic iron of "lime-induced chlorosis" peanut grown on a calcareous soil in relation to different soil moisture conditions. Results showed that chlorosis of peanuts developed under condition of high soil moisture level (250 g kg-1), while peanuts grew well and chlorosis did not develop when soil moisture was managed to a normal level (150 g kg-1). The malic acid, maleic acid and succinic acid contents of chlorotic peanut increased by 108.723, 0.029 and 22.446μg cm-2, respectively,compared with healthy peanuts. The content of citric acid and fumaric acid also increased in root exudates of chlorotic peanuts. On Days 28 and 42 of peanut growth, the accumulation of root apoplastic iron in chlorotic peanuts was higher than that of healthy peanuts. From Day 28 to Day 42, the mobilization percentages of chlorotic peanuts and healthy peanuts to root apoplastic iron were almost the same, being 52.4% and 52.8%,respectively, indicating that the chlorosis might be caused by the inactivation of iron within peanut plant grown on a calcareous soil under high soil moisture conditions.

  19. Plant regeneration and biochemical accumulation of hydroxybenzoic and hydroxycinnamic acid derivatives in Hypoxis hemerocallidea organ and callus cultures

    Moyo, M.; Amoo, S.O.; Aremu, A.O.; Grúz, Jiří; Šubrtová, Michaela; Doležal, Karel; van Staden, J.

    2014-01-01

    Roč. 227, OCT 2014 (2014), s. 157-164. ISSN 0168-9452 R&D Projects: GA MŠk(CZ) LO1204 Institutional support: RVO:61389030 Keywords : Antioxidants * Hydroxybenzoic acids * Hydroxycinnamic acids Subject RIV: EB - Genetics ; Molecular Biology Impact factor: 3.607, year: 2014

  20. Crassulacean acid metabolism under severe light limitation: a matter of plasticity in the shadows?

    Ceusters, Johan; Borland, Anne M; Godts, Christof; Londers, Elsje; Croonenborghs, Sarah; Van Goethem, Davina; De Proft, Maurice P

    2011-01-01

    Despite the increased energetic costs of CAM compared with C(3) photosynthesis, it is hypothesized that the inherent photosynthetic plasticity of CAM allows successful acclimation to light-limiting conditions. The present work sought to determine if CAM presented any constraints to short and longer term acclimation to light limitation and to establish if and how metabolic and photosynthetic plasticity in the deployment of the four phases of CAM might facilitate acclimation to conditions of deep shade. Measurements of leaf gas exchange, organic acids, starch and soluble sugar (glucose, fructose, and sucrose) contents were made in the leaves of the constitutive CAM bromeliad Aechmea 'Maya' over a three month period under severe light limitation. A. 'Maya' was not particularly tolerant of severe light limitation in the short term. A complete absence of net CO(2) uptake and fluctuations in key metabolites (i.e. malate, starch or soluble sugars) indicated a dampened metabolism whilst cell death in the most photosynthetically active leaves was attributed to an over-acidification of the cytoplasm. However, in the longer term, plasticity in the use of the different phases of gas exchange and different storage carbohydrate pools, i.e. a switch from starch to sucrose as the major carbohydrate source, ensured a positive carbon balance for this CAM species under extremely low levels of irradiance. As such, co-ordinated plasticity in the use of C(3) and C(4) carboxylases and different carbohydrate pools together with an increase in the abundance of light-harvesting complexes, appear to underpin the adaptive radiation of the energetically costly CAM pathway within light-limiting environments such as wet cloud forests and shaded understoreys of tropical forests. PMID:20861137

  1. Induced Protoporphyrin IX Accumulation by the δ-Aminolevulinic Acid in Bacteria and its Potential Use in the Photodynamic Therapy

    Brígido-Aparicio, Cyntiha; Ramón-Gallegos, Eva; Arenas-Huertero, Francisco Jesús; Uribe-Hernández, Raúl

    2008-08-01

    The increasing incident of resistant strains to antibiotic has encouraged the search of new antibacterial treatments, such as the photodynamic therapy. In recent years, photodynamic therapy has demonstrated being a good technology for the treatment of recurrent bacteria infection. PDT presents a hopeful approach to eliminate Gram positive and negative bacteria in immunological compromised patients. This therapy uses a laser in combination with a photosensibilizer in presence of intracellular molecular oxygen. The process generates an effect of phototoxicity in bacterial cells. The aim of this work was to determine the in vitro conditions to accumulate PpIX in effective concentrations in Staphylococcus aureus ATCC25923 and Streptococcus pyogenes, which are responsible of human cutaneous diseases. A cellular suspension of both strains was prepared in TSB to obtain growth in Log-phase, then, the suspensions were adjusted to a final concentration of 2.61×108 cells/mL. The strains were exposed to increasing concentrations from 0 to 160μg/mL of δ-ALA in order to determinate the concentration that induces the biggest accumulation of PpIX. PpIX was measured using the Piomelli method modified for bacteria. The concentration selected was 40 mg/mL of ALA. It was found that in basal concentration of δ-ALA (0 μg/mL) both strains accumulated similar amount of PpIX. In concentrations of 5 mg/mL of δ-ALA it was observed a significant (paureus ATCC25923 accumulated significantly the biggest concentration of PpIX with regard to S. pyogenes. In conclusion, it was found that the optimal conditions to apply PDT will be to expose both strains to 40 mg/mL of ALA and to irradiate at 24 h after the exposition.

  2. Antifungal canthin-6-one series accumulate in lipid droplets and affect fatty acid metabolism in Saccharomyces cerevisiae

    Lagoutte, D.; Nicolas, V; Poupon, E.; Fournet, Anne; Hocquemiller, R.; Libong, D.; Chaminade, P.; Loiseau, P.M.

    2008-01-01

    The mechanism of action of antifungal canthin-6-one series was investigated in Saccharomyces cerevisiae. After a rapid uptake, a preferential accumulation of the drug within lipid droplets was observed. The antifungal action of canthin-6-one was found as reversible. Canthin-6-one did not exhibit affinity for sterols, and membrane ergosterol was not necessary for the antifungal activity since the MICs were similar on an ergosterol-deleted and the wild-type S. cerevisiae clones. Relative amount...

  3. Increased placental fatty acid transporter 6 and binding protein 3 expression and fetal liver lipid accumulation in a mouse model of obesity in pregnancy.

    Díaz, Paula; Harris, Jessica; Rosario, Fredrick J; Powell, Theresa L; Jansson, Thomas

    2015-12-15

    Obesity in pregnancy is associated with increased fetal growth and adiposity, which, in part, is determined by transplacental nutrient supply. Trophoblast uptake and intracellular trafficking of lipids are dependent on placental fatty acid transport proteins (FATP), translocase (FAT/CD36), and fatty acid binding proteins (FABP). We hypothesized that maternal obesity in mice leads to increased placental expression of FAT/CD36, FATPs, and FABPs, and lipid accumulation in the fetal liver. C57/BL6J female mice were fed either a control (C; n = 10) or an obesogenic (OB; n = 10) high-fat, high-sugar diet before mating and throughout pregnancy. At E18.5, placentas and fetal livers were collected. Trophoblast plasma membranes (TPM) were isolated from placental homogenates. Expression of FAT/CD36 and FATP (TPM) and FABP (homogenates) was determined by immunoblotting. Gene expression was assessed by RT-quantitative PCR. Sections of fetal livers were stained for Oil Red O, and lipid droplets were quantified. TPM protein expression of FAT/CD36, FATP 2, and FATP 4 was comparable between C and OB groups. Conversely, TPM FATP 6 expression was increased by 35% in OB compared with C placentas without changes in mRNA expression. FABPs 1, 3-5 and PPARγ were expressed in homogenates, and FABP 3 expression increased 27% in OB compared with C placentas; however, no changes were observed in mRNA expression. Lipid droplet accumulation was 10-fold higher in the livers of fetuses from OB compared with C group. We propose that increased lipid transport capacity in obese mice promotes transplacental fatty acid transport and contributes to excess lipid accumulation in the fetal liver. PMID:26491104

  4. Limitation of fault-sealing and its control on hydrocarbon accumulation-An example from the Laoyemiao Oilfield of the Nanpu Sag

    Jiang Zhenxue; Dong Yuexia; Li Hongyi; Liu Luofu; Liu Guangdi; Li Xiaoying

    2008-01-01

    Based on previous studies on the internal structures of fault belts, the fault belts in the Laoyemiao Oilfieid of the Nanpu Sag can be divided into three units, a crushed zone, an upper induced fracture zone and a lower induced fracture zone according to the log response characteristics. The upper induced fracture zone is characterized by the development of pervasive fractures and has a poor sealing or non-sealing capability. It therefore can act as pathways for hydrocarbon migration. The lower induced fracture zone consists of fewer fractures and has limited sealing capability. The crushed zone has a good sealing capability comparable to mudstone and can thus prevent lateral migration of fluid.Through physical modeling and comparing laboratory data with calculated data of oil column heights of traps sealed by faults, it is concluded that the fault-sealing capability for oil and gas is limited. When the oil column height reaches a threshold, oil will spill over from the top of reservoir along the lower induced fracture zone under the action of buoyancy, and the size of reservoir will remain unchanged.Analysis of the formation mechanisms of the fault-sealed reservoirs in the Nanpu Sag indicated that the charging sequence of oil and gas in the reservoir was from lower formation to upper formation, with the fault playing an important role in oil and gas accumulation. The hydrocarbon potential in reverse faultsealed traps is much better than that in the consequent fault-sealed traps. The reverse fault-sealed traps are favorable and preferred exploration targets.

  5. Rice bran oil and oryzanol reduce plasma lipid and lipoprotein cholesterol concentrations and aortic cholesterol ester accumulation to a greater extent than ferulic acid in hypercholesterolemic hamsters.

    Wilson, Thomas A; Nicolosi, Robert J; Woolfrey, Benjamin; Kritchevsky, David

    2007-02-01

    plasma triglyceride concentrations compared to the control (-53% and -65%, respectively) and ferulic acid (-47% and -60%, respectively) diets. Hamsters fed the control and ferulic acid diets had significantly higher plasma vitamin E concentrations compared to the RBO (201% and 161%, respectively) and oryzanol (548% and 462%, respectively) diets; the ferulic acid and oryzanol diets had significantly lower plasma lipid hydroperoxide levels than the control (-57% and -46%, respectively) diet. The oryzanol-fed hamsters excreted significantly more coprostenol and cholesterol in their feces than the ferulic acid (127% and 120%, respectively) diet. The control diet had significantly greater aortic TC and FC accumulation compared to the RBO (115% and 89%, respectively), ferulic acid (48% and 58%, respectively) and the oryzanol (74% and 70%, respectively) diets. However, only the RBO and oryzanol diets had significantly lower aortic cholesterol ester accumulation compared to the control (-73% and -46%, respectively) diet. The present study suggests that at equal dietary levels, oryzanol has a greater effect on lowering plasma non-HDL-C levels and raising plasma HDL-C than ferulic acid, possibly through a greater extent to increase fecal excretion of cholesterol and its metabolites. However, ferulic acid may have a greater antioxidant capacity via its ability to maintain serum vitamin E levels compared to RBO and oryzanol. Thus, both oryzanol and ferulic acid may exert similar antiatherogenic properties, but through different mechanisms. PMID:16713234

  6. P Limitation and Microbial Biogeochemistry in Acidic Forest Soils of the Northeastern United States

    Smemo, K. A.; Deforest, J. L.; Burke, D. J.; Elliot, H. L.; Kluber, L. A.; Carrino-Kyker, S. R.

    2010-12-01

    In forest ecosystems with acidic soils, such as many hardwood forests of the Northeastern United States, net primary productivity should be limited by phosphorus (P) because P is biologically less available at pH temperate forests that have naturally acidic soil or are exposed to chronic acid deposition; such findings are contrary to biogeochemical expectations. We hypothesize that many eastern forests possess an underlying P limitation not realized at the ecosystem level. Instead, shifts in the composition, structure and function of soil microbial communities compensate by acquiring more P from organic sources and P limitation is therefore not manifested at the aboveground (plant) level. To test this hypothesis, we manipulated soil pH and P availability in 72 20 x 40 m mature hardwood forest plots across northeastern (glaciated) and southeastern (unglaciated) Ohio beginning in late summer 2009. Ten months after treatment initiation, soil pH has increased from 4.5 to 5.5 and soil P has increased from 3 to ~25 mg P/kg soil on glaciated soils and from 0.5 to ~5 mg P/kg soil on unglaciated soils. To quantify treatment responses, we measured the activity of soil extracellular enzymes associated with liberation of P, N, and C from organic matter, as well as pools of N and N cycling processes. We saw no significant effects of our treatments on pools of available ammonium or nitrate, nor did we see effects on net N mineralization and net nitrification rates. However, glaciated soils had significantly greater nitrate pools and higher N cycling rates than older unglaciated soils. Nitrogen and C cycling enzymes in treatment plots were not significantly different than control plots, but N-acetylglucosaminidase activity (N acquisition) was significantly greater in the unglaciated soils and β-glucosidase and cellobiosidase activities (C cycling) were greatest in the glaciated soils. In only the unglaciated soils was the activity of P acquisition enzymes (phosphomonoesterase

  7. Generation of transgenic wheat (Triticum aestivum L.) accumulating heterologous endo-xylanase or ferulic acid esterase in the endosperm

    Harholt, Jesper; Bach, Inga C; Lind-Bouquin, Solveig; Nunan, Kylie J.; Madrid, Susan M.; Brinch-Pedersen, Henrik; Holm, Preben B.; Scheller, Henrik V.

    2009-12-08

    Endo-xylanase (from Bacillus subtilis) or ferulic acid esterase (from Aspergillus niger) were expressed in wheat under the control of the endosperm specific 1DX5 glutenin promoter. Constructs both with and without the endoplasmic reticulum retention signal KDEL were used. Transgenic plants were recovered in all four cases but no qualitative differences could be observed whether KDEL was added or not. Endo-xylanase activity in transgenic grains was increased between two and three fold relative to wild type. The grains were shriveled and had a 25-33% decrease in mass. Extensive analysis of the cell walls showed a 10-15% increase in arabinose to xylose ratio, a 50% increase in the proportion of water extractable arabinoxylan, and a shift in the MW of the water extractable arabinoxylan from being mainly larger than 85 kD to being between 2 kD and 85 kD. Ferulic acid esterase expressing grains were also shriveled and the seed weight was decreased by 20-50%. No ferulic acid esterase activity could be detected in wild type grains whereas ferulic acid esterase activity was detected in transgenic lines. The grain cell walls had 15-40% increase in water unextractable arabinoxylan and a decrease in monomeric ferulic acid between 13 and 34%. In all the plants the observed changes are consistent with a plant response that serves to minimize the effect of the heterologously expressed enzymes by increasing arabinoxylan biosynthesis and cross-linking.

  8. Solar-thermal complex sample processing for nucleic acid based diagnostics in limited resource settings.

    Gumus, Abdurrahman; Ahsan, Syed; Dogan, Belgin; Jiang, Li; Snodgrass, Ryan; Gardner, Andrea; Lu, Zhengda; Simpson, Kenneth; Erickson, David

    2016-05-01

    The use of point-of-care (POC) devices in limited resource settings where access to commonly used infrastructure, such as water and electricity, can be restricted represents simultaneously one of the best application fits for POC systems as well as one of the most challenging places to deploy them. Of the many challenges involved in these systems, the preparation and processing of complex samples like stool, vomit, and biopsies are particularly difficult due to the high number and varied nature of mechanical and chemical interferents present in the sample. Previously we have demonstrated the ability to use solar-thermal energy to perform PCR based nucleic acid amplifications. In this work demonstrate how the technique, using similar infrastructure, can also be used to perform solar-thermal based sample processing system for extracting and isolating Vibrio Cholerae nucleic acids from fecal samples. The use of opto-thermal energy enables the use of sunlight to drive thermal lysing reactions in large volumes without the need for external electrical power. Using the system demonstrate the ability to reach a 95°C threshold in less than 5 minutes and maintain a stable sample temperature of +/- 2°C following the ramp up. The system is demonstrated to provide linear results between 10(4) and 10(8) CFU/mL when the released nucleic acids were quantified via traditional means. Additionally, we couple the sample processing unit with our previously demonstrated solar-thermal PCR and tablet based detection system to demonstrate very low power sample-in-answer-out detection. PMID:27231636

  9. Solar-thermal complex sample processing for nucleic acid based diagnostics in limited resource settings

    Gumus, Abdurrahman; Ahsan, Syed; Dogan, Belgin; Jiang, Li; Snodgrass, Ryan; Gardner, Andrea; Lu, Zhengda; Simpson, Kenneth; Erickson, David

    2016-01-01

    The use of point-of-care (POC) devices in limited resource settings where access to commonly used infrastructure, such as water and electricity, can be restricted represents simultaneously one of the best application fits for POC systems as well as one of the most challenging places to deploy them. Of the many challenges involved in these systems, the preparation and processing of complex samples like stool, vomit, and biopsies are particularly difficult due to the high number and varied nature of mechanical and chemical interferents present in the sample. Previously we have demonstrated the ability to use solar-thermal energy to perform PCR based nucleic acid amplifications. In this work demonstrate how the technique, using similar infrastructure, can also be used to perform solar-thermal based sample processing system for extracting and isolating Vibrio Cholerae nucleic acids from fecal samples. The use of opto-thermal energy enables the use of sunlight to drive thermal lysing reactions in large volumes without the need for external electrical power. Using the system demonstrate the ability to reach a 95°C threshold in less than 5 minutes and maintain a stable sample temperature of +/− 2°C following the ramp up. The system is demonstrated to provide linear results between 104 and 108 CFU/mL when the released nucleic acids were quantified via traditional means. Additionally, we couple the sample processing unit with our previously demonstrated solar-thermal PCR and tablet based detection system to demonstrate very low power sample-in-answer-out detection. PMID:27231636

  10. Cd and Ni transport and accumulation in the halophyte Sesuvium portulacastrum: implication of organic acids in these processes

    Mnasri, Mejda; Ghabriche, Rim; Fourati, Emna; Zaier, Hanen; Sabally, Kebba; Barrington, Suzelle; Lutts, Stanley; Abdelly, Chedly; Ghnaya, Tahar

    2015-01-01

    The implication of organic acids in Cd and Ni translocation was studied in the halophyte species Sesuvium portulacastrum. Citric, fumaric, malic, and ascorbic acids were separated and quantified by HPLC technique in shoots, roots and xylem saps of plants grown on nutrient solutions added with 50 μM Cd, 100 μM Ni and the combination of 50 μM Cd + 100 μM Ni. Results showed that Cd had no significant impact on biomass production while Ni and the combination of both metals drastically affected pl...

  11. Cd and Ni transport and accumulation in the halophyte Sesuvium portulacastrum: implication of organic acids in these processes

    Tahar eGhnaya

    2015-01-01

    The implication of organic acids in Cd and Ni translocation was studied in the halophyte species Sesuvium portulacastrum. Citric, fumaric, malic and ascorbic acids were separated and quantified by HPLC technique in shoots, roots and xylem saps of plants grown on nutrient solutions added with 50 µM Cd, 100 µM Ni and the combination of 50 µM Cd + 100 µM Ni. Results showed that Cd had no significant impact on biomass production while Ni and the combination of both metals drastically affected pla...

  12. Impact of mixed low-molecular-weight organic acids on uranium accumulation and distribution in a variant of mustard (Brassica juncea var. tumida)

    The impact of a mixture of low-molecular-weight organic acids (LMWOAs) composed of CA/MA/OA/LA with a molar ratio of 2.5:2.31:1.15:0.044 on uranium (U) accumulation and distribution in mustard (Brassica juncea var. tumida) was studied in this paper in order to understand the mechanism of rhizosphere-exudation assisted phytoremediation by hydroponic and pot culture experiments. The impact of the mixture of LWMOAs (Mix) on U accumulation showed that in hydroponic conditions Mix could enhance U translocation from root-to-shoot in mustard, but inhibit U uptake in root. In pot experiments, Mix enhanced both root and shoot U accumulation in mustard. The time-dependent kinetics of U uptake in mustard on Mix treatment showed that U content in plant shoots and roots increased with time increasing, and the steady state conditions were obtained at the 8th and 5th day with the U content of 1,528 and 2,300 mg/kg, respectively. Transmission electron microscope and energy dispersive X-ray spectrometry analysis for mustard roots showed that U was mainly observed on cell membrane of mustard roots on Mix treatment. This study would provide new insights for the mixture of LWMOAs-assisted phytoremediation of U-contaminated soil. (author)

  13. Generation of transgenic wheat (Triticum aestivum L.) accumulating heterologous endo-xylanase or ferulic acid esterase in the endosperm

    Harholt, Jesper; Bach, Inga Christensen; Lind Bouquin, Solveig; Nunan, Kylie J.; Madrid, Susan M.; Brinch-Pedersen, Henrik; Holm, Preben Bach; Scheller, Henrik Vibe

    2010-01-01

    Endo-xylanase (from Bacillus subtilis) or ferulic acid esterase (from Aspergillus niger) were expressed in wheat under the control of the endosperm-specific 1DX5 glutenin promoter. Constructs both with and without the endoplasmic reticulum retention signal (Lys-Asp-Glu-Leu) KDEL were used. Transg...

  14. Accumulation of Rare Earth Elements in Spinach and Soil under Condition of Using REE and Acid Rain Stress

    严重玲; 洪业汤; 林鹏; 王世杰; 李心清; 梁洁

    2002-01-01

    The content and distribution characteristics of REE in spinach and soil under using REE and acid rain stress were studied by pot experiments. The results show that the content of REE is 0.527~0.696 (μgg-1) in the above-ground portion of spinach, 2.668~3.003 (μg*g-1) in the under-ground portion of spinach and 229.09~250.30 (μg*g-1) in the soil. With the acidity of acid rain increasing, the leaching of REE in plants and soil is strengthened and the amount of REE reduces with decreasing of pH value. After REE are used, though plants show the selective absorption to Ce group elements (especially spraying on leaves), regardless under acid rain stress or using REE or not, the distribution model of REE in the above-ground and under-ground portion of plants is basically the same with the control. Plants also follow the Oddo-Harkins rule of the REE of distribution abundance, light rare earth elements is enriched, the minus of Eu is abnormal and admeasure of Ce is a rich model. The results show that REE in plants mainly come from soil and are affected by it.

  15. Biofiltration of fishpond effluents and accumulation of N-compounds (phycobiliproteins and mycosporine-like amino acids) versus C-compounds (polysaccharides) in Hydropuntia cornea (Rhodophyta)

    The biofiltration capacity, biomass-yield and accumulation of N- and C-compounds of Hydropuntia cornea were analyzed. Algae were grown in different conditions for 28 d: outdoor and indoor, with or without fishpond effluents. N-uptake efficiency of these effluents was higher than 95% after 7 d both outdoors and indoors. N-enriched conditions reduced the extent of photoinhibition and increased the maximal quantum yield in H. cornea. The biomass-yield was higher in outdoor grown-algae after 7 d and decreased independently of the treatment after 28 d. N, acid polysaccharide (AP) and mycosporine-like amino acid (MAA)-yields decreased throughout the experiment in all conditions. The highest MAA-yield was observed in fishpond effluent outdoor-grown algae, indicating a positive effect of increased radiation on MAA accumulation. However, APs were higher under N-depleted conditions. The use of MAAs as UV-screening and antioxidants, and the use of AP as immunostimulants are discussed.

  16. Accumulation, selection and covariation of amino acids in sieve tube sap of tansy (Tanacetum vulgare) and castor bean (Ricinus communis): evidence for the function of a basic amino acid transporter and the absence of a γ-amino butyric acid transporter.

    Bauer, Susanne N; Nowak, Heike; Keller, Frank; Kallarackal, Jose; Hajirezaei, Mohamad-Reza; Komor, Ewald

    2014-09-01

    Sieve tube sap was obtained from Tanacetum by aphid stylectomy and from Ricinus after apical bud decapitation. The amino acids in sieve tube sap were analyzed and compared with those from leaves. Arginine and lysine accumulated in the sieve tube sap of Tanacetum more than 10-fold compared to the leaf extracts and they were, together with asparagine and serine, preferably selected into the sieve tube sap, whereas glycine, methionine/tryptophan and γ-amino butyric acid were partially or completely excluded. The two basic amino acids also showed a close covariation in sieve tube sap. The acidic amino acids also grouped together, but antagonistic to the other amino acids. The accumulation ratios between sieve tube sap and leaf extracts were smaller in Ricinus than in Tanacetum. Arginine, histidine, lysine and glutamine were enriched and preferentially loaded into the phloem, together with isoleucine and valine. In contrast, glycine and methionine/tryptophan were partially and γ-amino butyric acid almost completely excluded from sieve tube sap. The covariation analysis grouped arginine together with several neutral amino acids. The acidic amino acids were loaded under competition with neutral amino acids. It is concluded from comparison with the substrate specificities of already characterized plant amino acid transporters, that an AtCAT1-like transporter functions in phloem loading of basic amino acids, whereas a transporter like AtGAT1 is absent in phloem. Although Tanacetum and Ricinus have different minor vein architecture, their phloem loading specificities for amino acids are relatively similar. PMID:24446756

  17. Pattern of accumulation of inorganic elements in sunflower (helianthus annuus l.) plants subjected to salt stress and exogenous application of 5-aminolevulinic acid

    Influence of a potential plant growth regulator, 5-aminolevulinic acid (5-ALA) on the pattern of accumulation of some key inorganic elements in salt-stressed sunflower plants was observed under greenhouse conditions. Two cultivars of sunflower viz., Hysun-33 and S-278 were grown under non-saline and saline (150 mM NaCl) regimes in sand culture. After two weeks of salt treatment, all plants were subjected to four (0 (no spray), 20, 50 and 80 mg L/sup -1/) levels of 5-ALA as a foliar spray for 14 days. Shoot fresh and dry matter of both sunflower cultivars was markedly reduced due to salt stress. Of different inorganic ions, Na/sup +/ and Cl/sup -/ in leaf, stem and root tissues increased markedly while, K/sup +/, and Ca/sup 2+/ in all these tissues reduced under the saline regime. However, salt stress did not alter the leaf, stem or root P as well as root K/sup +/ /Na//sup +/ ratio. Foliar-applied ALA improved growth under normal (non-saline) and saline conditions, and 20 and 80 mg L/sup -1/ levels of 5-ALA were relatively more effective than the other levels used in this study. Of nutrient accumulation, 5-ALA altered only root Na/sup +/ and K/sup +/ and root K/sup +//Na/sup +/ ratio e.g., root Na/sup +/ was lower at 50 mg L/sup -1/, while root K/sup +/and K/sup +//Na/sup +/ ratio were higher at 80 mg L/sup -1/. In contrast, accumulation of all other ions in plant organs remained unaffected. Overall, foliar-applied 5-ALA did not alter the accumulation of different nutrients in different plant parts except root Na/sup +/, K/sup +/ and K/sup +//Na/sup +/ ratio in both sunflower cultivars. (author)

  18. Excessive ammonia inhibited transcription of MsU2 gene and furthermore affected accumulation distribution of allantoin and amino acids in alfalfa Medicago sativa

    WANG Li; JIANG Lin-lin; Nomura Mika; Tajima Shigeyuki; CHENG Xian-guo

    2015-01-01

    In legume plants, uricase gene (Nodulin-35) plays a positive role in metabolism of ureide and amide compounds in symbiotic nitrogen-ifxing in the nodules. In this study, a pot experiment was performed to examine the effects of ammonium application on the transcription of MsU2 gene and distribution of major nitrogen compounds in alfalfa Medicago sativa. Data showed that alfalfa plant has a signiifcant difference in contents of nitrogen compounds in xylem saps compared with soybean plant, and belongs to typical amide type legume plants with little ureide accumulation, and the accumulation of asparagines and ureide in the tissues of alfalfa is mainly gathered in the nodules. Northern blotting showed that excessive ammonium signiifcantly inhibited the transcription of MsU2 gene in the nodules and roots, and mRNA accumulation of MsU2 gene in the plants exposed to excessive ammonium decreased gradual y with culture time extension, indicating that application of ammonium signiifcantly inhibited the transcription of MsU2 gene in the alfalfa plants. Although the application of exces-sive ammonium increased the contents of amino acids in various tissues of alfalfa, the accumulation of al antoin relfecting the strength of uricase activity is remarkably reduced in the xylem saps, stems and nodules when alfalfa plants exposed to excessive ammonium, suggesting that application of excessive ammonium generated a negative effect on symbiosis ifxing-nitrogen system due to inhibition of ammonium ion on uricase activity in the nodules of alfalfa. This result seems to imply that application of excessive ammonium in legume plants should not be proposed to avoid affecting the ability of ifxing nitrogen in the nodules of legume plants, and reasonable dose of ammonium should be recommended to effectively utilize the ifxed N from atmosphere in legume plant production.

  19. Regulation of amino-acid metabolism controls flux to lipid accumulation in Yarrowia lipolytica

    Kerkhoven, Eduard J.; Pomraning, Kyle R.; Baker, Scott E.; Nielsen, Jens

    2016-01-01

    Yarrowia lipolytica is a promising microbial cell factory for the production of lipids to be used as fuels and chemicals, but there are few studies on regulation of its metabolism. Here we performed the first integrated data analysis of Y. lipolytica grown in carbon and nitrogen limited chemostat...... is similar to the overflow metabolism observed in many other microorganisms, e.g. ethanol production by Sacchromyces cerevisiae at nitrogen limitation....

  20. Foliar abscisic acid-to-ethylene accumulation and response regulate shoot growth sensitivity to mild drought in wheat

    Valluru, Ravi; Davies, William John; Reynolds, Matthew; Dodd, Ian Charles

    2016-01-01

    Although, plant hormones play an important role in adjusting growth in response to environmental perturbation, the relative contributions of abscisic acid (ABA) and ethylene remain elusive. Using six spring wheat genotypes differing for stress tolerance, we show that young seedlings of the drought-tolerant (DT) group maintained or increased shoot dry weight (SDW) while the drought-susceptible (DS) group decreased SDW in response to mild drought. Both the DT and DS groups increased endogenous ...

  1. Foliar abscisic acid-to-ethylene accumulation and response regulate shoot growth sensitivity to mild drought in wheat

    Ravi eValluru; William J eDavies; Matthew P eReynolds; Ian C eDodd

    2016-01-01

    Although plant hormones play an important role in adjusting growth in response to environmental perturbation, the relative contributions of abscisic acid (ABA) and ethylene remain elusive. Using six spring wheat genotypes differing for stress tolerance, we show that young seedlings of the drought-tolerant (DT) group maintained or increased shoot dry weight (SDW) while the drought-susceptible (DS) group decreased SDW in response to mild drought. Both the DT and DS groups increased endogenous A...

  2. Novel Inhibitory Effects of Glycyrrhizic Acid on the Accumulation of Advanced Glycation End Product and Its Receptor Expression

    Cheng, Hong Sheng; Kong, Joana Magdelene Xiao Fang; Ng, Athena Xin Hui; Chan, Weng Keong; Ton, So Ha; Abdul Kadir, Khalid

    2014-01-01

    Abstract Beneficial effects of glycyrrhizic acid (GA), a bioactive extract of licorice root, in the prevention of metabolic syndrome have been consistently reported while advanced glycation end products (AGE) and receptor for advanced glycation end product (RAGE) are the leading factors in the development of diabetes mellitus. The aim of this study was to investigate the effects of GA on the AGE-RAGE axis using high-fat/high-sucrose (HF/HS) diet-induced metabolic syndrome rat models. Twenty f...

  3. Oostatic peptides containing d-amino acids: synthesis, oostatic activity, degradation, accumulation in ovaries and NMR study

    Hlaváček, Jan; Tykva, Richard; Holík, Josef; Bennettová, Blanka; Buděšínský, Miloš; Vlasáková, Věra; Černý, Bohuslav; Slaninová, Jiřina

    2012-01-01

    Roč. 42, č. 5 (2012), s. 1715-1725. ISSN 0939-4451 R&D Projects: GA ČR GA203/06/1272 Institutional research plan: CEZ:AV0Z40550506; CEZ:AV0Z50380511; CEZ:AV0Z50070508 Keywords : D-amino acids * oostatic peptide synthesis * H-3 labeling * oostatic activity in Neobellieria bullata * H-3 incorporation * Peptide degradation * NMR study Subject RIV: CC - Organic Chemistry Impact factor: 3.914, year: 2012

  4. Cardiomyocyte Triglyceride Accumulation and Reduced Ventricular Function in Mice with Obesity Reflect Increased Long Chain Fatty Acid Uptake and De Novo Fatty Acid Synthesis

    Fengxia Ge

    2012-01-01

    Full Text Available A nonarteriosclerotic cardiomyopathy is increasingly seen in obese patients. Seeking a rodent model, we studied cardiac histology, function, cardiomyocyte fatty acid uptake, and transporter gene expression in male C57BL/6J control mice and three obesity groups: similar mice fed a high-fat diet (HFD and db/db and ob/ob mice. At sacrifice, all obesity groups had increased body and heart weights and fatty livers. By echocardiography, ejection fraction (EF and fractional shortening (FS of left ventricular diameter during systole were significantly reduced. The Vmax for saturable fatty acid uptake was increased and significantly correlated with cardiac triglycerides and insulin concentrations. Vmax also correlated with expression of genes for the cardiac fatty acid transporters Cd36 and Slc27a1. Genes for de novo fatty acid synthesis (Fasn, Scd1 were also upregulated. Ten oxidative phosphorylation pathway genes were downregulated, suggesting that a decrease in cardiomyocyte ATP synthesis might explain the decreased contractile function in obese hearts.

  5. Survival of mycobacteria depends on proteasome-mediated amino acid recycling under nutrient limitation

    Elharar, Yifat; Roth, Ziv; Hermelin, Inna; Moon, Alexandra; Peretz, Gabriella; Shenkerman, Yael; Vishkautzan, Marina; Khalaila, Isam; Gur, Eyal

    2014-01-01

    Intracellular protein degradation is an essential process in all life domains. While in all eukaryotes regulated protein degradation involves ubiquitin tagging and the 26S-proteasome, bacterial prokaryotic ubiquitin-like protein (Pup) tagging and proteasomes are conserved only in species belonging to the phyla Actinobacteria and Nitrospira. In Mycobacterium tuberculosis, the Pup-proteasome system (PPS) is important for virulence, yet its physiological role in non-pathogenic species has remained an enigma. We now report, using Mycobacterium smegmatis as a model organism, that the PPS is essential for survival under starvation. Upon nitrogen limitation, PPS activity is induced, leading to accelerated tagging and degradation of many cytoplasmic proteins. We suggest a model in which the PPS functions to recycle amino acids under nitrogen starvation, thereby enabling the cell to maintain basal metabolic activities. We also find that the PPS auto-regulates its own activity via pupylation and degradation of its components in a manner that promotes the oscillatory expression of PPS components. As such, the destructive activity of the PPS is carefully balanced to maintain cellular functions during starvation. PMID:24986881

  6. Propensity to metal accumulation and oxidative stress responses of two benthic species (Cerastoderma edule and Nephtys hombergii): are tolerance processes limiting their responsiveness?

    Marques, Ana

    2016-02-24

    The chronic exposure of benthic organisms to metals in sediments can lead to the development of tolerance mechanisms, thus diminishing their responsiveness. This study aims to evaluate the accumulation profiles of V, Cr, Co, Ni, As, Cd, Pb and Hg and antioxidant system responses of two benthic organisms (Cerastoderma edule, Bivalvia; Nephtys hombergii, Polychaeta). This approach will provide clarifications about the ability of each species to signalise metal contamination. Organisms of both species were collected at the Tagus estuary, in two sites with distinct contamination degrees (ALC, slightly contaminated; BAR, highly contaminated). Accordingly, C. edule accumulated higher concentrations of As, Pb and Hg at BAR compared to ALC. However, antioxidant responses of C. edule were almost unaltered at BAR and no peroxidative damage occurred, suggesting adjustment mechanisms to the presence of metals. In contrast, N. hombergii showed a minor propensity to metal accumulation, only signalising spatial differences for As and Pb and accumulating lower concentrations of metals than C. edule. The differences in metal accumulation observed between species might be due to their distinctive foraging behaviour and/or the ability of N. hombergii to minimise the metal uptake. Despite that, the accumulation of As and Pb was on the basis of the polychaete antioxidant defences inhibition at BAR, including CAT, SOD, GR and GPx. The integrated biomarker response index (IBRv2) confirmed that N. hombergii was more affected by metal exposure than C. edule. In the light of current findings, in field-based studies, the information of C. edule as a bioindicator should be complemented by that provided by another benthic species, since tolerance mechanisms to metals can hinder a correct diagnosis of sediment contamination and of the system’s health. Overall, the present study contributed to improve the lack of fundamental knowledge of two widespread and common estuarine species, providing

  7. Propensity to metal accumulation and oxidative stress responses of two benthic species (Cerastoderma edule and Nephtys hombergii): are tolerance processes limiting their responsiveness?

    Marques, Ana; Piló, David; Araújo, Olinda; Pereira, Fábio; Guilherme, Sofia; Carvalho, Susana; Santos, Maria Ana; Pacheco, Mário; Pereira, Patrícia

    2016-05-01

    The chronic exposure of benthic organisms to metals in sediments can lead to the development of tolerance mechanisms, thus diminishing their responsiveness. This study aims to evaluate the accumulation profiles of V, Cr, Co, Ni, As, Cd, Pb and Hg and antioxidant system responses of two benthic organisms (Cerastoderma edule, Bivalvia; Nephtys hombergii, Polychaeta). This approach will provide clarifications about the ability of each species to signalise metal contamination. Organisms of both species were collected at the Tagus estuary, in two sites with distinct contamination degrees (ALC, slightly contaminated; BAR, highly contaminated). Accordingly, C. edule accumulated higher concentrations of As, Pb and Hg at BAR compared to ALC. However, antioxidant responses of C. edule were almost unaltered at BAR and no peroxidative damage occurred, suggesting adjustment mechanisms to the presence of metals. In contrast, N. hombergii showed a minor propensity to metal accumulation, only signalising spatial differences for As and Pb and accumulating lower concentrations of metals than C. edule. The differences in metal accumulation observed between species might be due to their distinctive foraging behaviour and/or the ability of N. hombergii to minimise the metal uptake. Despite that, the accumulation of As and Pb was on the basis of the polychaete antioxidant defences inhibition at BAR, including CAT, SOD, GR and GPx. The integrated biomarker response index (IBRv2) confirmed that N. hombergii was more affected by metal exposure than C. edule. In the light of current findings, in field-based studies, the information of C. edule as a bioindicator should be complemented by that provided by another benthic species, since tolerance mechanisms to metals can hinder a correct diagnosis of sediment contamination and of the system's health. Overall, the present study contributed to improve the lack of fundamental knowledge of two widespread and common estuarine species, providing

  8. Phase transformations of high-purity PbI2 nanoparticles synthesized from lead-acid accumulator anodes

    Malevu, T. D.; Ocaya, R. O.; Tshabalala, K. G.

    2016-09-01

    High-purity hexagonal lead iodide nanoparticles have been synthesized from a depleted sealed lead acid battery anode. The synthesized product was found to consist of the rare 6R polytype form of PbI2 that is thought to have good potential in photovoltaic applications. We investigate the effects of annealing time and post-melting temperature on the structure and optical properties using 1.5418 Å CuKα radiation. Photoluminescence measurements were done under 150 W/221 nm wavelength xenon excitation. Phase transformation was observed through XRD peaks when annealing time increased from 0.5-5 h. The nanoparticle grain size and inter-planar distance appeared to be independent of annealing time. PL measurements show three broad peaks in a range of 400 nm to 700 nm that are attributed to excitonic, donor-acceptor pair and luminescence bands from the deep levels.

  9. Silencing of ABCC13 transporter in wheat reveals its involvement in grain development, phytic acid accumulation and lateral root formation.

    Bhati, Kaushal Kumar; Alok, Anshu; Kumar, Anil; Kaur, Jagdeep; Tiwari, Siddharth; Pandey, Ajay Kumar

    2016-07-01

    Low phytic acid is a trait desired in cereal crops and can be achieved by manipulating the genes involved either in its biosynthesis or its transport in the vacuoles. Previously, we have demonstrated that the wheat TaABCC13 protein is a functional transporter, primarily involved in heavy metal tolerance, and a probable candidate gene to achieve low phytate wheat. In the current study, RNA silencing was used to knockdown the expression of TaABCC13 in order to evaluate its functional importance in wheat. Transgenic plants with significantly reduced TaABCC13 transcripts in either seeds or roots were selected for further studies. Homozygous RNAi lines K1B4 and K4G7 exhibited 34-22% reduction of the phytic acid content in the mature grains (T4 seeds). These transgenic lines were defective for spike development, as characterized by reduced grain filling and numbers of spikelets. The seeds of transgenic wheat had delayed germination, but the viability of the seedlings was unaffected. Interestingly, early emergence of lateral roots was observed in TaABCC13-silenced lines as compared to non-transgenic lines. In addition, these lines also had defects in metal uptake and development of lateral roots in the presence of cadmium stress. Our results suggest roles of TaABCC13 in lateral root initiation and enhanced sensitivity towards heavy metals. Taken together, these data demonstrate that wheat ABCC13 is functionally important for grain development and plays an important role during detoxification of heavy metals. PMID:27342224

  10. Effect of surfactant on hydrolysis products accumulation and short-chain fatty acids (SCFA) production during mesophilic and thermophilic fermentation of waste activated sludge: kinetic studies.

    Zhang, Peng; Chen, Yinguang; Zhou, Qi

    2010-09-01

    In the presence of surfactant sodium dodecylbenzene sulfonate (SDBS) the hydrolysis products accumulation and the short-chain fatty acids (SCFA) production during waste activated sludge fermentation under mesophilic and thermophilic conditions was compared with that at room temperature. In order to understand the mechanism of significant amounts of mesophilic and thermophilic hydrolysis products and SCFA observed in the presence of surfactant, the kinetic models at different SDBS dosages were developed. It was found that SDBS increased the mesophilic and thermophilic hydrolysis rate significantly, and the maximum specific utilization of hydrolysis products increased at low SDBS and decreased at high one. However, the observed maximum specific utilization of SCFA decreased seriously with SDBS increase. In the presence of SDBS the decay rate of acidogenic bacteria not only was lower than that in the absence of SDBS but decreased with the increase of SDBS under either mesophilic or thermophilic conditions. PMID:20409704

  11. Salicylic acid treatment reduces the rot of postharvest citrus fruit by inducing the accumulation of H2O2, primary metabolites and lipophilic polymethoxylated flavones.

    Zhu, Feng; Chen, Jiajing; Xiao, Xue; Zhang, Mingfei; Yun, Ze; Zeng, Yunliu; Xu, Juan; Cheng, Yunjiang; Deng, Xiuxin

    2016-09-15

    To comprehensively analyze the effects of salicylic acid (SA) on the storability of Satsuma mandarin (Citrus unshiu), fruits were treated with 2mM SA. The disease incidence of control/SA-treated fruit at 50d and 120d after treatment was 23.3%/10% and 67.3%/23.3%, respectively, suggesting that SA treatment can significantly reduce the rot rate of postharvest citrus fruit. Fruit quality assays revealed that the treatment can maintain fruit firmness without affecting the inner quality. Furthermore, the contents of H2O2 and some defense-related metabolites, such as ornithine and threonine, in citrus pericarp, were significantly increased by SA treatment. Moreover, it was lipophilic polymethoxylated flavones, rather than flavanone glycosides, that accumulated in SA-treated fruits and these can directly inhibit pathogen development. These results suggest that the effects of SA on postharvest citrus fruit may be attributed to the accumulation of H2O2 and defense-related metabolites. PMID:27080881

  12. Impact of Precooling and Controlled-Atmosphere Storage on γ-Aminobutyric Acid (GABA) Accumulation in Longan (Dimocarpus longan Lour.) Fruit.

    Zhou, Molin; Ndeurumio, Kessy H; Zhao, Lei; Hu, Zhuoyan

    2016-08-24

    Longan (Dimocarpus longan Lour.) fruit cultivars 'Chuliang' and 'Shixia' were analyzed for γ-aminobutyric acid (GABA) accumulation after precooling and in controlled-atmosphere storage. Fruit were exposed to 5% O2 plus 3%, 5%, or 10% CO2 at 4 °C, and GABA and associated enzymes, aril firmness, and pericarp color were measured. Aril softening and pericarp browning were delayed by 5% CO2 + 5% O2. GABA concentrations and glutamate decarboxylase (GAD; EC 4.1.1.15) activities declined during storage at the higher-CO2 treatments. However, GABA aminotransferase (GABA-T; EC 2.6.1.19) activities in elevated CO2-treated fruit fluctuated during storage. GABA concentrations increased after precooling treatments. GAD activity and GABA-T activity were different between cultivars after precooling. GABA concentrations in fruit increased after 3 days of 10% CO2 + 5% O2 treatment and then declined as storage time increased. GABA accumulation was associated with stimulation of GAD activity rather than inhibition of GABA-T activity. PMID:27412947

  13. Low Temperature-Induced 30 (LTI30 positively regulates drought stress resistance in Arabidopsis: effect on abscisic acid sensitivity and hydrogen peroxide accumulation

    Haitao eShi

    2015-10-01

    Full Text Available As a dehydrin belonging to group II late embryogenesis abundant protein (LEA family, Arabidopsis Low Temperature-Induced 30 (LTI30/XERO2 has been shown to be involved in plant freezing stress resistance. However, the other roles of AtLTI30 remain unknown. In this study, we found that the expression of AtLTI30 was largely induced by drought stress and abscisic acid (ABA treatments. Thereafter, AtLTI30 knockout mutants and overexpressing plants were isolated to investigate the possible involvement of AtLTI30 in ABA and drought stress responses. AtLTI30 knockout mutants were less sensitive to ABA-mediated seed germination, while AtLTI30 overexpressing plants were more sensitive to ABA compared with wild type (WT. Consistently, the AtLTI30 knockout mutants displayed decreased drought stress resistance, while the AtLTI30 overexpressing plants showed improved drought stress resistance compared with WT, as evidenced by a higher survival rate and lower leaf water loss than WT after drought stress. Moreover, manipulation of AtLTI30 expression positively regulated the activities of catalases (CATs and endogenous proline content, as a result, negatively regulated drought stress-triggered hydrogen peroxide (H2O2 accumulation. All these results indicate that AtLTI30 is a positive regulator of plant drought stress resistance, partially through the modulation of ABA sensitivity, H2O2 and proline accumulation.

  14. The effect of cis-jasmone, jasmonic acid and methyl jasmonate on accumulation of anthocyanins and proanthocyanidins in seedlings of common buckwheat (Fagopyrum esculentum Moench

    Marcin Horbowicz

    2011-04-01

    Full Text Available Effects of various jasmonates (methyl jasmonate, jasmonic acid, cis-jasmone on anthocyanins and procyanidins content of, as well as on growth of common buckwheat (Fagopyrum esculentum Moench seedlings were studied. The studied jasmonates were applied as solutions or vapors on four days seedlings, and the seedlings were grown during the next four days in day/night conditions (16/8 h. Afterwards anthocyanins and proanthocyanidins content, as well as elongation of primary roots and hypocotyls were measured. When applied as solutions cis-jasmone (JAS stimulated the anthocyanins accumulation, but when used as vapors had tendency to decrease its accumulation in buckwheat hypocotyls. Jasmonic acid (JA solutions slightly stimulated or had no effect on biosynthesis of anthocyanins in buckwheat hypocotyls, but used as vapors caused a decline of anthocyanins in buckwheat hypocotyls. Methyl jasmonate (MJ clearly inhibited biosynthesis of anthocyanins in hypocotyls of buckwheat seedlings. The studied jasmonates had no influence on anthocyanins level in cotyledons of buckwheat seedlings, except cis-jasmone, which at the lowest solution concentration slightly enhanced biosynthesis of the pigments. Treatment of buckwheat seedlings with solutions of all jasmonates (10-8 M, 10-6 M and 10-4 M had no influence on the growth of buckwheat hypocotyls. Contrary to that observation vapors of the growth regulators in concentrations 10-4 M, had a strong inhibitory effect on the growth of hypocotyls of buckwheat seedlings. Solutions of JA and MJ, as well as vapors of JA, MJ and JAS strongly inhibited the primary root growth of buckwheat seedlings, while JAS applied as solution had no such influence. MJ and JA caused much higher stimulation of proanthocyanidin biosynthesis in buckwheat hypocotyls than JAS.

  15. Leptosphaeria maculans effector AvrLm4-7 affects salicylic acid (SA) and ethylene (ET) signalling and hydrogen peroxide (H2 O2 ) accumulation in Brassica napus.

    Nováková, Miroslava; Šašek, Vladimír; Trdá, Lucie; Krutinová, Hana; Mongin, Thomas; Valentová, Olga; Balesdent, Marie-HelEne; Rouxel, Thierry; Burketová, Lenka

    2016-08-01

    To achieve host colonization, successful pathogens need to overcome plant basal defences. For this, (hemi)biotrophic pathogens secrete effectors that interfere with a range of physiological processes of the host plant. AvrLm4-7 is one of the cloned effectors from the hemibiotrophic fungus Leptosphaeria maculans 'brassicaceae' infecting mainly oilseed rape (Brassica napus). Although its mode of action is still unknown, AvrLm4-7 is strongly involved in L. maculans virulence. Here, we investigated the effect of AvrLm4-7 on plant defence responses in a susceptible cultivar of B. napus. Using two isogenic L. maculans isolates differing in the presence of a functional AvrLm4-7 allele [absence ('a4a7') and presence ('A4A7') of the allele], the plant hormone concentrations, defence-related gene transcription and reactive oxygen species (ROS) accumulation were analysed in infected B. napus cotyledons. Various components of the plant immune system were affected. Infection with the 'A4A7' isolate caused suppression of salicylic acid- and ethylene-dependent signalling, the pathways regulating an effective defence against L. maculans infection. Furthermore, ROS accumulation was decreased in cotyledons infected with the 'A4A7' isolate. Treatment with an antioxidant agent, ascorbic acid, increased the aggressiveness of the 'a4a7' L. maculans isolate, but not that of the 'A4A7' isolate. Together, our results suggest that the increased aggressiveness of the 'A4A7' L. maculans isolate could be caused by defects in ROS-dependent defence and/or linked to suppressed SA and ET signalling. This is the first study to provide insights into the manipulation of B. napus defence responses by an effector of L. maculans. PMID:26575525

  16. Effects of Ghrelin on Triglyceride Accumulation and Glucose Uptake in Primary Cultured Rat Myoblasts under Palmitic Acid-Induced High Fat Conditions

    Lingling Han

    2015-01-01

    Full Text Available This study aimed to study the effects of acylated ghrelin on glucose and triglyceride metabolism in rat myoblasts under palmitic acid- (PA- induced high fat conditions. Rat myoblasts were treated with 0, 10−11, 10−9, or 10−7 M acylated ghrelin and 0.3 mM PA for 12 h. Triglyceride accumulation was determined by Oil-Red-O staining and the glycerol phosphate dehydrogenase-peroxidase enzymatic method, and glucose uptake was determined by isotope tracer. The glucose transporter 4 (GLUT4, AMP-activated protein kinase (AMPK, acetyl-CoA carboxylase (ACC, and uncoupling protein 3 (UCP3 were assessed by RT-PCR and western blot. Compared to 0.3 mM PA, ghrelin at 10−9 and 10−7 M reduced triglyceride content (5.855 ± 0.352 versus 5.030 ± 0.129 and 4.158 ± 0.254 mM, P<0.05 and prevented PA-induced reduction of glucose uptake (1.717 ± 0.264 versus 2.233 ± 0.333 and 2.333 ± 0.273 10−2 pmol/g/min, P<0.05. The relative protein expression of p-AMPKα/AMPKα, UCP3, and p-ACC under 0.3 mM PA was significantly reduced compared to controls (all P<0.05, but those in the 10−9 and 10−7 M ghrelin groups were significantly protected from 0.3 mM PA (all P<0.05. In conclusion, acylated ghrelin reduced PA-induced triglyceride accumulation and prevented the PA-induced decrease in glucose uptake in rat myoblasts. These effects may involve fatty acid oxidation.

  17. Endogenous Synthesis of Amino Acids Limits Growth, Lactation, and Reproduction in Animals.

    Hou, Yongqing; Yao, Kang; Yin, Yulong; Wu, Guoyao

    2016-03-01

    Amino acids (AAs) are building blocks of protein. Eight AAs (Ala, Asn, Asp, Glu, Gln, Gly, Pro, and Ser) are formed by all animals, whereas de novo synthesis of Arg occurs in a species-specific manner in most mammals (e.g., humans, pigs, and rats). Synthesizable AAs were traditionally classified as nutritionally nonessential for animals, because they were thought to be formed in sufficient amounts. However, this assumption is not supported by evidence showing that 1) rats grow slowly when their diets do not contain Arg, Glu, or Gln despite adequate provision of all other proteinogenous AAs; 2) pigs cannot achieve maximum growth, lactation, or reproduction performance when fed corn- and soybean meal-based diets meeting National Research Council-recommended requirements of protein and AAs without supplemental Arg, Glu, Gln, Gly, or Pro; 3) chickens exhibit increases in lean tissue gain and feed efficiency when their diets are supplemented with Glu, Gln, Gly, and Pro; 4) lactating cows cannot obtain maximum milk protein production without a postruminal supply of Gln or Pro; 5) fish cannot achieve maximum growth when diets do not contain Gln or Pro; and 6) men fail to sustain spermatogenesis when fed an Arg-deficient diet. Quantitative analysis of nitrogen metabolism showed that AA synthesis in animals is constrained by both precursor availability and enzyme activity. Taken together, these findings support the conclusion that the endogenous synthesis of AAs limits growth, lactation, and reproduction in animals. This new knowledge can guide the optimization of human nutrition for improving health and well-being. PMID:26980816

  18. High molecular weight hyaluronic acid limits astrocyte activation and scar formation after spinal cord injury

    Khaing, Zin Z.; Milman, Brian D.; Vanscoy, Jennifer E.; Seidlits, Stephanie K.; Grill, Raymond J.; Schmidt, Christine E.

    2011-08-01

    A major hurdle for regeneration after spinal cord injury (SCI) is the ability of axons to penetrate and grow through the scar tissue. After SCI, inflammatory cells, astrocytes and meningeal cells all play a role in developing the glial scar. In addition, degradation of native high molecular weight (MW) hyaluronic acid (HA), a component of the extracellular matrix, has been shown to induce activation and proliferation of astrocytes. However, it is not known if the degradation of native HA actually enhances glial scar formation. We hypothesize that the presence of high MW HA (HA with limited degradation) after SCI will decrease glial scarring. Here, we demonstrate that high MW HA decreases cell proliferation and reduces chondroitin sulfate proteoglycan (CSPG) production in cultured neonatal and adult astrocytes. In addition, stiffness-matched high MW HA hydrogels crosslinked to resist degradation were implanted in a rat model of spinal dorsal hemisection injury. The numbers of immune cells (macrophages and microglia) detected at the lesion site in animals with HA hydrogel implants were significantly reduced at acute time points (one, three and ten days post-injury). Lesioned animals with HA implants also exhibited significantly lower CSPG expression at ten days post-injury. At nine weeks post-injury, animals with HA hydrogel implants exhibited a significantly decreased astrocytic response, but did not have significantly altered CSPG expression. Combined, these data suggest that high MW HA, when stabilized against degradation, mitigates astrocyte activation in vitro and in vivo. The presence of HA implants was also associated with a significant decrease in CSPG deposition at ten days after SCI. Therefore, HA-based hydrogel systems hold great potential for minimizing undesired scarring as part of future repair strategies after SCI.

  19. Similar PAH fate in anaerobic digesters inoculated with three microbial communities accumulating either volatile fatty acids or methane.

    Florence Braun

    Full Text Available Urban sludge produced on wastewater treatment plants are often contaminated by organic pollutants such as polycyclic aromatic hydrocarbons (PAH. Their removal under methanogenic conditions was already reported, but the factors influencing this removal remain unclear. Here, we determined the influence of microbial communities on PAH removal under controlled physico-chemical conditions. Twelve mesophilic anaerobic digesters were inoculated with three microbial communities extracted from ecosystems with contrasting pollution histories: a PAH contaminated soil, a PCB contaminated sediment and a low contaminated anaerobic sludge. These anaerobic digesters were operated during 100 days in continuous mode. A sterilised activated sludge, spiked with 13 PAH at concentrations usually encountered in full-scale wastewater treatment plants, was used as substrate. The dry matter and volatile solid degradation, the biogas production rate and composition, the volatile fatty acids (VFA production and the PAH removals were monitored. Bacterial and archaeal communities were compared in abundance (qPCR, in community structure (SSCP fingerprinting and in dominant microbial species (454-pyrosequencing. The bioreactors inoculated with the community extracted from low contaminated anaerobic sludge showed the greater methane production. The PAH removals ranged from 10% to 30%, respectively, for high and low molecular weight PAH, whatever the inoculums tested, and were highly correlated with the dry matter and volatile solid removals. The microbial community structure and diversity differed with the inoculum source; this difference was maintained after the 100 days of digestion. However, the PAH removal was not correlated to these diverse structures and diversities. We hence obtained three functional stable consortia with two contrasted metabolic activities, and three different pictures of microbial diversity, but similar PAH and matter removals. These results confirm

  20. Rapid Phosphatidic Acid Accumulation in Response to Low Temperature Stress in Arabidopsis is Generated through Diacylglycerol Kinase

    Steven A. Arisz

    2013-01-01

    Full Text Available Phosphatidic acid (PtdOH is emerging as an important signalling lipid in abiotic stress responses in plants. The effect of cold stress was monitored using 32P-labelled seedlings and leaf discs of Arabidopsis thaliana. Low, non-freezing temperatures were found to trigger a very rapid 32P-PtdOH increase, peaking within 2 and 5 min, respectively. In principle, PtdOH can be generated through three different pathways, i.e. i via de novo phospholipid biosynthesis (through acylation of lyso-PtdOH, ii via phospholipase D hydrolysis of structural phospholipids or iii via phosphorylation of diacylglycerol (DAG by DAG kinase (DGK. Using a differential 32P-labelling protocol and a PLD-transphosphatidylation assay, evidence is provided that the rapid 32P-PtdOH response was primarily generated through DGK. A simultaneous decrease in the levels of 32P-PtdInsP, correlating in time, temperature dependency and magnitude with the increase in 32P-PtdOH, suggested that a PtdInsP-hydrolyzing PLC generated the DAG in this reaction. Testing T-DNA insertion lines available for the seven DGK genes, revealed no clear changes in 32P-PtdOH responses, suggesting functional redundancy. Similarly, known cold-stress mutants were analyzed to investigate whether the PtdOH response acted downstream of the respective gene products. The hos1, los1 and fry1 mutants were found to exhibit normal PtdOH responses. Slight changes were found for ice1, snow1, and the overexpression line Super-ICE1, however, this was not cold-specific and likely due to pleiotropic effects. A tentative model illustrating direct cold effects on phospholipid metabolism is presented.

  1. Experimentally Testing the Hypothesis of a Limited Amino Acid Repertoire in Primitive Proteins

    Akanuma, S.; Nakajima, Y.; Yokobori, S.; Yamagishi, A.

    2013-11-01

    It has been argued that a fewer amino acids were used in primitive proteins and later the repertoire increased up to 20. To test this hypothesis experimentally, we restricted the amino acid usage of a reconstructed, ancestral protein to reduced sets.

  2. Intake of a Western diet containing cod instead of pork alters fatty acid composition in tissue phospholipids and attenuates obesity and hepatic lipid accumulation in mice.

    Liisberg, Ulrike; Fauske, Kristin Røen; Kuda, Ondrej; Fjære, Even; Myrmel, Lene Secher; Norberg, Nina; Frøyland, Livar; Graff, Ingvild Eide; Liaset, Bjørn; Kristiansen, Karsten; Kopecky, Jan; Madsen, Lise

    2016-07-01

    The content of the marine n-3 polyunsaturated fatty acids (PUFAs), eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) is far lower in lean than in fatty seafood. Cod filets contain less than 2g fat per kg, whereof approximately 50% is EPA and DHA. However, a large fraction of these n-3 PUFAs is present in the phospholipid (PL) fraction and may have high bioavailability and capacity to change the endocannabinoid profile. Here we investigated whether exchanging meat from a lean terrestrial animal with cod in a background Western diet would alter the endocannabinoid tone in mice and thereby attenuate obesity development and hepatic lipid accumulation. Accordingly, we prepared iso-caloric diets with 15.1 energy (e) % protein, 39.1 e% fat and 45.8 e% carbohydrates using freeze-dried meat from cod filets or pork sirloins, and using a combination of soybean oil, corn oil, margarine, milk fat, and lard as the fat source. Compared with mice receiving diets containing pork, mice fed cod gained less adipose tissue mass and had a lower content of hepatic lipids. This was accompanied by a lower n-6 to n-3 ratio in liver PLs and in red blood cells (RBCs) in the mice. Furthermore, mice receiving the cod-containing diet had lower circulating levels of the two major endocannabinoids, N-arachidonoylethanolamine and 2-arachidonoylglycerol. Together, our data demonstrate that despite the relatively low content of n-3 PUFAs in cod fillets, the cod-containing diet could exert beneficial metabolic effects. PMID:27155918

  3. Involvement of sigmaS accumulation in repression of the flhDC operon in acidic phospholipid-deficient mutants of Escherichia coli.

    Uchiyama, Junji; Nobue, Yuka; Zhao, Hong; Matsuzaki, Hiroshi; Nagahama, Hideki; Matsuoka, Satoshi; Matsumoto, Kouji; Hara, Hiroshi

    2010-06-01

    Escherichia coli pgsA mutations, which cause acidic phospholipid deficiency, repress transcription of the flagellar master operon flhDC, and thus impair flagellar formation and motility. The molecular mechanism of the strong repression of flhDC transcription in the mutant cells, however, has not yet been clarified. In order to shed light on this mechanism we isolated genes which, when supplied in multicopy, suppress the repression of flhD, and found that three genes, gadW, metE and yeaB, were capable of suppression. Taking into account a previous report that gadW represses sigma(S) production, the level of sigma(S) in the pgsA3 mutant was examined. We found that pgsA3 cells had a high level of sigma(S) and that introduction of a gadW plasmid into pgsA3 cells did reduce the sigma(S) level. The pgsA3 cells exhibited a sharp increase in sigma(S) levels that can only be partially attributed to the slight increase in rpoS transcription; the largest part of the effect is due to a post-transcriptional accumulation of sigma(S). GadW in multicopy exerts its effect by post-transcriptionally downregulating sigma(S). YeaB and MetE in multicopy also exert their effect via sigma(S). Disruption of rpoS caused an increase of the flhD mRNA level, and induction from P(trc)-rpoS repressed the flhD mRNA level. The strong repression of flhD transcription in pgsA3 mutant cells is thus suggested to be caused by the accumulated sigma(S). PMID:20185506

  4. Comparison of trans-1-amino-3-[18 F]fluorocyclobutanecarboxylic acid (anti-[18 F]FACBC) accumulation in lymph node prostate cancer metastasis and lymphadenitis in rats

    Introduction: Trans-1-amino-3-[18 F]fluorocyclobutanecarboxylic acid (anti-[18 F]FACBC) is a positron emission tomography (PET) tracer used to visualize prostate cancer (PCa). In this study, we investigated the differences in anti-[18 F]FACBC accumulation between metastatic and inflamed lymph node (LN) lesions. Methods: A PCa LN metastasis (PLM) model was developed by inoculating a rat PCa cell line, MAT-Ly-Lu-B2, into popliteal LNs of Copenhagen rats. Acute lymphadenitis (AL) was induced by injecting concanavalin A (Con A) into the hind footpad, and chronic lymphadenitis (CL) was induced by daily injection of Con A into the tissues surrounding the popliteal LNs for 2 weeks. Main lesions of all animal models were established in lumbar and/or inguinal LNs. Biodistribution and dynamic PET imaging data were acquired after tracer injection. T2-weighted magnetic resonance (MR) images were registered with PET images. Results: In the biodistribution study, the uptake ratios of PLM-to-lymphadenitis in lesional lumbar and inguinal LNs were 0.97 − 1.57 and 1.47 − 2.08 at 15 and 60 min post-anti-[18 F]FACBC injection respectively. In PET imaging, the lesional lumbar LNs of CL and PLM, but not of AL, were visualized on anti-[18 F]FACBC-PET/MR fusion images without disturbance from radioactivity from urine, and the rank order of anti-[18 F]FACBC accumulation at 50 − 60 post-injection in lesional lumbar LNs was PLM > CL > AL. Conclusions: Anti-[18 F]FACBC accumulation in LNs with PLM was higher than that in inflamed LNs. Advances in knowledge: The study showed that although low but significant levels of anti-[18 F]FACBC uptake by chronic inflamed lesions might cause false-positives in anti-[18 F]FACBC-PET in some PCa patients, uptake of the tracer at acutely inflamed sites was minimal. Implications for patient care: The findings of this study suggest the potential of Anti-[18 F]FACBC for distinguishing between tumors and acute inflammation in clinical practice

  5. What makes ribosome-mediated transcriptional attenuation sensitive to amino Acid limitation?

    2005-06-01

    Full Text Available Ribosome-mediated transcriptional attenuation mechanisms are commonly used to control amino acid biosynthetic operons in bacteria. The mRNA leader of such an operon contains an open reading frame with "regulatory" codons, cognate to the amino acid that is synthesized by the enzymes encoded by the operon. When the amino acid is in short supply, translation of the regulatory codons is slow, which allows transcription to continue into the structural genes of the operon. When amino acid supply is in excess, translation of regulatory codons is rapid, which leads to termination of transcription. We use a discrete master equation approach to formulate a probabilistic model for the positioning of the RNA polymerase and the ribosome in the attenuator leader sequence. The model describes how the current rate of amino acid supply compared to the demand in protein synthesis (signal determines the expression of the amino acid biosynthetic operon (response. The focus of our analysis is on the sensitivity of operon expression to a change in the amino acid supply. We show that attenuation of transcription can be hyper-sensitive for two main reasons. The first is that its response depends on the outcome of a race between two multi-step mechanisms with synchronized starts: transcription of the leader of the operon, and translation of its regulatory codons. The relative change in the probability that transcription is aborted (attenuated can therefore be much larger than the relative change in the time it takes for the ribosome to read a regulatory codon. The second is that the general usage frequencies of codons of the type used in attenuation control are small. A small percentage decrease in the rate of supply of the controlled amino acid can therefore lead to a much larger percentage decrease in the rate of reading a regulatory codon. We show that high sensitivity further requires a particular choice of regulatory codon among several synonymous codons for the

  6. What makes ribosome-mediated transcriptional attenuation sensitive to amino acid limitation?

    Johan Elf

    2005-06-01

    Full Text Available Ribosome-mediated transcriptional attenuation mechanisms are commonly used to control amino acid biosynthetic operons in bacteria. The mRNA leader of such an operon contains an open reading frame with "regulatory" codons, cognate to the amino acid that is synthesized by the enzymes encoded by the operon. When the amino acid is in short supply, translation of the regulatory codons is slow, which allows transcription to continue into the structural genes of the operon. When amino acid supply is in excess, translation of regulatory codons is rapid, which leads to termination of transcription. We use a discrete master equation approach to formulate a probabilistic model for the positioning of the RNA polymerase and the ribosome in the attenuator leader sequence. The model describes how the current rate of amino acid supply compared to the demand in protein synthesis (signal determines the expression of the amino acid biosynthetic operon (response. The focus of our analysis is on the sensitivity of operon expression to a change in the amino acid supply. We show that attenuation of transcription can be hyper-sensitive for two main reasons. The first is that its response depends on the outcome of a race between two multi-step mechanisms with synchronized starts: transcription of the leader of the operon, and translation of its regulatory codons. The relative change in the probability that transcription is aborted (attenuated can therefore be much larger than the relative change in the time it takes for the ribosome to read a regulatory codon. The second is that the general usage frequencies of codons of the type used in attenuation control are small. A small percentage decrease in the rate of supply of the controlled amino acid can therefore lead to a much larger percentage decrease in the rate of reading a regulatory codon. We show that high sensitivity further requires a particular choice of regulatory codon among several synonymous codons for the

  7. What makes ribosome-mediated transcriptional attenuation sensitive to amino acid limitation?

    Elf, Johan; Ehrenberg, Måns

    2005-06-01

    Ribosome-mediated transcriptional attenuation mechanisms are commonly used to control amino acid biosynthetic operons in bacteria. The mRNA leader of such an operon contains an open reading frame with "regulatory" codons, cognate to the amino acid that is synthesized by the enzymes encoded by the operon. When the amino acid is in short supply, translation of the regulatory codons is slow, which allows transcription to continue into the structural genes of the operon. When amino acid supply is in excess, translation of regulatory codons is rapid, which leads to termination of transcription. We use a discrete master equation approach to formulate a probabilistic model for the positioning of the RNA polymerase and the ribosome in the attenuator leader sequence. The model describes how the current rate of amino acid supply compared to the demand in protein synthesis (signal) determines the expression of the amino acid biosynthetic operon (response). The focus of our analysis is on the sensitivity of operon expression to a change in the amino acid supply. We show that attenuation of transcription can be hyper-sensitive for two main reasons. The first is that its response depends on the outcome of a race between two multi-step mechanisms with synchronized starts: transcription of the leader of the operon, and translation of its regulatory codons. The relative change in the probability that transcription is aborted (attenuated) can therefore be much larger than the relative change in the time it takes for the ribosome to read a regulatory codon. The second is that the general usage frequencies of codons of the type used in attenuation control are small. A small percentage decrease in the rate of supply of the controlled amino acid can therefore lead to a much larger percentage decrease in the rate of reading a regulatory codon. We show that high sensitivity further requires a particular choice of regulatory codon among several synonymous codons for the same amino acid. We

  8. Optical limiting response of multi-walled carbon nanotube-phthalocyanine nanocomposite in solution and when in poly (acrylic acid)

    Sekhosana, Kutloano Edward; Nyokong, Tebello

    2016-08-01

    Bis{23-(3,4-di-yloxybenzoic acid)-(2(3), 9(10), 16(17), 23(24)-(hexakis-pyridin-3-yloxy phthalocyaninato)} dineodymium (III) acetate (3) is linked to amino-functionalized multi-walled carbon nanotubes (MWCNT) to form 3-MWCNT. Z-scan technique was employed to experimentally determine the nonlinear absorption coefficient from the open-aperture data. The limiting threshold values as low as 0.045 J cm-2 were found in solution. The conjugate (3-MWCNT) gave better optical limiting behavior than complex 3 alone.

  9. 籽用南瓜种子发育过程中脂肪酸积累模式%Accumulation pattern of fatty acids during pumpkin ( Cucurbita maxima Duch) seed development

    屈淑平; 常影; 秦俊芬; 邢伟; 崔崇士

    2011-01-01

    Accumulation pattern of fatty acids during seed development of seed pumpkin (Cucurbita maxima cv Yinhui 1) was investigated using GC -MS method. Results showed eight fatty acids in mature pumpkin seeds. They were oleic acid, linoleic acid, cetylic acid, stearic acid, arachic acid, myristic acid, palmitoleic acid and linolenic acid. The quantity of crude fat changed during seed development in Z curve. During accumulation, there were negative correlation between oleic acid (C18: 1) and linolenic acid (C18: 2), and positive correlation among other fatty acids.%以籽用南瓜品种银辉一号为材料对南瓜种子发育过程中脂肪酸的累积过程进行了分析.结果表明,成熟的南瓜种子中可检测到8种脂肪酸,按含量高低依次为:油酸、亚油酸、棕榈酸、硬脂酸、花生酸、豆蔻酸、棕榈油酸、亚麻酸.南瓜种子粗脂肪含量的积累模式呈现升-降-升的Z字型变化模式.在累积过程中除了C18∶1和C1∶2有负相关性外,其它脂肪酸相互之间显示了高度的正相关性.

  10. Arachidonic acid alters tomato HMG expression and fruit growth and induces 3-hydroxy-3-methylglutaryl coenzyme A reductase-independent lycopene accumulation

    Rodriguez-Concepcion, M.; Gruissem, W. [Univ. of California, Berkeley, CA (United States). Dept. of Plant and Microbial Biology

    1999-01-01

    Regulation of isoprenoid end-product synthesis required for normal growth and development in plants is not well understood. To investigate the extent to which specific genes for the enzyme 3-hydroxy-3-methylglutaryl coenzyme A reductase (HMGR) are involved in end-product regulation, the authors manipulated expression of the HMG1 and HMG2 genes in tomato (Lycopersicon esculentum) fruit using arachidonic acid (AA). In developing young fruit AA blocked fruit growth, inhibited HMG1, and activated HMG2 expression. These results are consistent with other reports indicating that HMG1 expression is closely correlated with growth processes requiring phytosterol production. In mature-green fruit AA strongly induced the expression of HMG2, PSY1 (the gene for phytoene synthase), and lycopene accumulation before the normal onset of carotenoid synthesis and ripening. The induction of lycopene synthesis was not blocked by inhibition of HMGR activity using mevinolin, suggesting that cytoplasmic HMGR is not required for carotenoid synthesis. Their results are consistent with the function of an alternative plastid isoprenoid pathway (the Rohmer pathway) that appears to direct the production of carotenoids during tomato fruit ripening.