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Sample records for acid-induced stress resistance

  1. Natural resistance to ascorbic acid induced oxidative stress is mainly mediated by catalase activity in human cancer cells and catalase-silencing sensitizes to oxidative stress

    Klingelhoeffer Christoph

    2012-05-01

    against oxidative stress mediated by ascorbic acid induced hydrogen peroxide production. The antioxidative enzyme catalase is important to protect cancer cells against cytotoxic hydrogen peroxide. Silenced catalase expression increased the susceptibility of the formerly resistant cancer cell line BT-20 to oxidative stress.

  2. Withaferin A protects against palmitic acid-induced endothelial insulin resistance and dysfunction through suppression of oxidative stress and inflammation

    Kalaivani Batumalaie; Muhammad Arif Amin; Dharmani Devi Murugan; Munavvar Zubaid Abdul Sattar; Nor Azizan Abdullah

    2016-01-01

    Activation of inflammatory pathways via reactive oxygen species (ROS) by free fatty acids (FFA) in obesity gives rise to insulin resistance and endothelial dysfunction. Withaferin A (WA), possesses both antioxidant and anti-inflammatory properties and therefore would be a good strategy to suppress palmitic acid (PA)-induced oxidative stress and inflammation and hence, insulin resistance and dysfunction in the endothelium. Effect of WA on PA-induced insulin resistance in human umbilical vein e...

  3. Withaferin A protects against palmitic acid-induced endothelial insulin resistance and dysfunction through suppression of oxidative stress and inflammation.

    Batumalaie, Kalaivani; Amin, Muhammad Arif; Murugan, Dharmani Devi; Sattar, Munavvar Zubaid Abdul; Abdullah, Nor Azizan

    2016-01-01

    Activation of inflammatory pathways via reactive oxygen species (ROS) by free fatty acids (FFA) in obesity gives rise to insulin resistance and endothelial dysfunction. Withaferin A (WA), possesses both antioxidant and anti-inflammatory properties and therefore would be a good strategy to suppress palmitic acid (PA)-induced oxidative stress and inflammation and hence, insulin resistance and dysfunction in the endothelium. Effect of WA on PA-induced insulin resistance in human umbilical vein endothelial cells (HUVECs) was determined by evaluating insulin signaling mechanisms whilst effect of this drug on PA-induced endothelial dysfunction was determined in acetylcholine-mediated relaxation in isolated rat aortic preparations. WA significantly inhibited ROS production and inflammation induced by PA. Furthermore, WA significantly decreased TNF-α and IL-6 production in endothelial cells by specifically suppressing IKKβ/NF-κβ phosphorylation. WA inhibited inflammation-stimulated IRS-1 serine phosphorylation and improved the impaired insulin PI3-K signaling, and restored the decreased nitric oxide (NO) production triggered by PA. WA also decreased endothelin-1 and plasminogen activator inhibitor type-1 levels, and restored the impaired endothelium-mediated vasodilation in isolated aortic preparations. These findings suggest that WA inhibited both ROS production and inflammation to restore impaired insulin resistance in cultured endothelial cells and improve endothelial dysfunction in rat aortic rings. PMID:27250532

  4. Natural resistance to ascorbic acid induced oxidative stress is mainly mediated by catalase activity in human cancer cells and catalase-silencing sensitizes to oxidative stress

    Klingelhoeffer Christoph; Kämmerer Ulrike; Koospal Monika; Mühling Bettina; Schneider Manuela; Kapp Michaela; Kübler Alexander; Germer Christoph-Thomas; Otto Christoph

    2012-01-01

    Abstract Background Ascorbic acid demonstrates a cytotoxic effect by generating hydrogen peroxide, a reactive oxygen species (ROS) involved in oxidative cell stress. A panel of eleven human cancer cell lines, glioblastoma and carcinoma, were exposed to serial dilutions of ascorbic acid (5-100 mmol/L). The purpose of this study was to analyse the impact of catalase, an important hydrogen peroxide-detoxifying enzyme, on the resistance of cancer cells to ascorbic acid mediated oxidative stress. ...

  5. CD36 Mediated Fatty Acid-Induced Podocyte Apoptosis via Oxidative Stress.

    Wei Hua

    Full Text Available Hyperlipidemia-induced apoptosis mediated by fatty acid translocase CD36 is associated with increased uptake of ox-LDL or fatty acid in macrophages, hepatocytes and proximal tubular epithelial cells, leading to atherosclerosis, liver damage and fibrosis in obese patients, and diabetic nephropathy (DN, respectively. However, the specific role of CD36 in podocyte apoptosis in DN with hyperlipidemia remains poorly investigated.The expression of CD36 was measured in paraffin-embedded kidney tissue samples (Ctr = 18, DN = 20 by immunohistochemistry and immunofluorescence staining. We cultured conditionally immortalized mouse podocytes (MPC5 and treated cells with palmitic acid, and measured CD36 expression by real-time PCR, Western blot analysis and immunofluorescence; lipid uptake by Oil red O staining and BODIPY staining; apoptosis by flow cytometry assay, TUNEL assay and Western blot analysis; and ROS production by DCFH-DA fluorescence staining. All statistical analyses were performed using SPSS 21.0 statistical software.CD36 expression was increased in kidney tissue from DN patients with hyperlipidemia. Palmitic acid upregulated CD36 expression and promoted its translocation from cytoplasm to plasma membrane in podocytes. Furthermore, palmitic acid increased lipid uptake, ROS production and apoptosis in podocytes, Sulfo-N-succinimidyloleate (SSO, the specific inhibitor of the fatty acid binding site on CD36, decreased palmitic acid-induced fatty acid accumulation, ROS production, and apoptosis in podocytes. Antioxidant 4-hydroxy-2,2,6,6- tetramethylpiperidine -1-oxyl (tempol inhibited the overproduction of ROS and apoptosis in podocytes induced by palmitic acid.CD36 mediated fatty acid-induced podocyte apoptosis via oxidative stress might participate in the process of DN.

  6. Ameliorative effects of polyunsaturated fatty acids against palmitic acid-induced insulin resistance in L6 skeletal muscle cells

    Sawada Keisuke

    2012-03-01

    Full Text Available Abstract Background Fatty acid-induced insulin resistance and impaired glucose uptake activity in muscle cells are fundamental events in the development of type 2 diabetes and hyperglycemia. There is an increasing demand for compounds including drugs and functional foods that can prevent myocellular insulin resistance. Methods In this study, we established a high-throughput assay to screen for compounds that can improve myocellular insulin resistance, which was based on a previously reported non-radioisotope 2-deoxyglucose (2DG uptake assay. Insulin-resistant muscle cells were prepared by treating rat L6 skeletal muscle cells with 750 μM palmitic acid for 14 h. Using the established assay, the impacts of several fatty acids on myocellular insulin resistance were determined. Results In normal L6 cells, treatment with saturated palmitic or stearic acid alone decreased 2DG uptake, whereas unsaturated fatty acids did not. Moreover, co-treatment with oleic acid canceled the palmitic acid-induced decrease in 2DG uptake activity. Using the developed assay with palmitic acid-induced insulin-resistant L6 cells, we determined the effects of other unsaturated fatty acids. We found that arachidonic, eicosapentaenoic and docosahexaenoic acids improved palmitic acid-decreased 2DG uptake at lower concentrations than the other unsaturated fatty acids, including oleic acid, as 10 μM arachidonic acid showed similar effects to 750 μM oleic acid. Conclusions We have found that polyunsaturated fatty acids, in particular arachidonic and eicosapentaenoic acids prevent palmitic acid-induced myocellular insulin resistance.

  7. Resistance to ursodeoxycholic acid-induced growth arrest can also result in resistance to deoxycholic acid-induced apoptosis and increased tumorgenicity

    There is a large body of evidence which suggests that bile acids increase the risk of colon cancer and act as tumor promoters, however, the mechanism(s) of bile acids mediated tumorigenesis is not clear. Previously we showed that deoxycholic acid (DCA), a tumorogenic bile acid, and ursodeoxycholic acid (UDCA), a putative chemopreventive agent, exhibited distinct biological effects, yet appeared to act on some of the same signaling molecules. The present study was carried out to determine whether there is overlap in signaling pathways activated by tumorogenic bile acid DCA and chemopreventive bile acid UDCA. To determine whether there was an overlap in activation of signaling pathways by DCA and UDCA, we mutagenized HCT116 cells and then isolated cell lines resistant to UDCA induced growth arrest. These lines were then tested for their response to DCA induced apoptosis. We found that a majority of the cell lines resistant to UDCA-induced growth arrest were also resistant to DCA-induced apoptosis, implying an overlap in DCA and UDCA mediated signaling. Moreover, the cell lines which were the most resistant to DCA-induced apoptosis also exhibited a greater capacity for anchorage independent growth. We conclude that UDCA and DCA have overlapping signaling activities and that disregulation of these pathways can lead to a more advanced neoplastic phenotype

  8. Saturated Fatty Acid Induces Insulin Resistance Partially Through Nucleotide-binding Oligomerization Domain 1 Signaling Pathway in Adipocytes

    Yi-jun Zhou; Yin-si Tang; Yu-ling Song; Ai Li; Hui Zhou; Yan Li

    2013-01-01

    Objective To investigate the potential role of nucleotide-binding oligomerization domain 1 (NOD1), a component of the innate immune system, in mediating lipid-induced insulin resistance in adipocytes. Methods Adipocytes from Toll-like receptor 4 deficiency mice were used for stimulation experiments. The effect of oleate/palmitate mixture on nuclear factor-κB (NF-κB) activation was analyzed by reporter plasmid assay. The release of proinflammatory chemokine/cytokines production was determined by using real-time PCR. Insulin-stimulated glucose uptake was measured by 2-deoxy-D-[3H] glucose uptake assay. Chemokine/cytokine expression and glucose uptake in adipocytes transfected with small interfering RNA (siRNA) targeting NOD1 upon fatty acids treatment were analyzed. Results Oleate/palmitate mixture activated the NF-κB pathway and induced interleukin-6, tumor necrosis factor-α, and monocyte chemoattractant protein-1 mRNA expressions in adipocytes from mice deficient in Toll-like receptor 4, and these effects were blocked by siRNA targeting NOD1. Furthermore, saturated fatty acids decreased the ability of insulin-stimulated glucose uptake. Importantly, siRNA targeting NOD1 partially reversed saturated fatty acid-induced suppression of insulin-induced glucose uptake. Conclusion NOD1 might play an important role in saturated fatty acid-induced insulin resistance in adipocytes, suggesting a mechanism by which reduced NOD1 activity confers beneficial effects on insulin action.

  9. DL-β-aminobutyric acid-induced resistance in soybean against Aphis glycines Matsumura (Hemiptera: Aphididae.

    Yunpeng Zhong

    Full Text Available Priming can improve plant innate capability to deal with the stresses caused by both biotic and abiotic factors. In this study, the effect of DL-β-amino-n-butyric acid (BABA against Aphis glycines Matsumura, the soybean aphid (SA was evaluated. We found that 25 mM BABA as a root drench had minimal adverse impact on plant growth and also efficiently protected soybean from SA infestation. In both choice and non-choice tests, SA number was significantly decreased to a low level in soybean seedlings drenched with 25 mM BABA compared to the control counterparts. BABA treatment resulted in a significant increase in the activities of several defense enzymes, such as phenylalanine ammonia-lyase (PAL, peroxidase (POX, polyphenol oxidase (PPO, chitinase (CHI, and β-1, 3-glucanase (GLU in soybean seedlings attacked by aphid. Meanwhile, the induction of 15 defense-related genes by aphid, such as AOS, CHS, MMP2, NPR1-1, NPR1-2, and PR genes, were significantly augmented in BABA-treated soybean seedlings. Our study suggest that BABA application is a promising way to enhance soybean resistance against SA.

  10. Berberine reverses free-fatty-acid-induced insulin resistance in 3T3-L1 adipocytes through targeting IKKβ

    2008-01-01

    AIM:To investigate the effects and molecular mechanisms of berberine on improving insulin resistance induced by free fatty acids (FFAs) in 3T3-LI adipocytes.METHODS:The model of insulin resistance in 3T3-L1 adipocytes was established by adding palmic acid (0.5 mmol/L) to the culture medium.Berberine treatment was performed at the same time.Glucose uptake rate was determined by the 2-deoxy-[3H]-Dglucose method.The levels of IkB kinase beta (IKKβ)Ser181 phosphorylation,insulin receptor substrate1(IRS-1) Ser307 phosphorylation,expression of IKKβ,IRS-1,nuclear transcription factor kappaB p65 (NF-κB p65),phosphatidylinositol-3-kinase p85(PI-3K p85) and glucose transporter 4 (GLUT4) proteins were detected by Western blotting.The distribution of NF-κB p65 proteins inside the adipocytes was observed through confocal laser scanning microscopy(CLSM).RESULTS:After the intervention of palmic acid for 24 h,the insulin-stimulated glucose transport in 3T3-L1 adipocytes was inhibited by 67%.Meanwhile,the expression of IRS-1 and PI-3K p85 protein was reduced,while the levels of IKKβ Ser181 and IRS-1 Ser307 phosphorylation,and nuclear translocation of NF-κB p65 protein were increased.However,the above indexes,which indicated the existence of insulin resistance,were reversed by berberine although the expression of GLUT4,IKKβ and total NF-κB p65 protein were not changed during this study.CONCLUSION:Insulin resistance induced by FFAs in 3T3-L1 adipocytes can be improved by berberine.Berberine reversed free-fatty-acid-induced insulin resistance in 3T3-L1 adipocytes through targeting IKKβ.

  11. Salicylic acid induces differential antioxidant response in spring maize under high temperature stress.

    Khanna, Palak; Kaur, Kamaljit; Gupta, Anil K

    2016-06-01

    High temperature is one of the important stress factors that affect crops in tropical countries. Plants do evolve or adopt different mechanisms to overcome such stress for survival. It is an interesting subject and has attracted many researchers to work upon. Here, we studied the effect of salicylic acid (SA) on seedling growth and antioxidative defense system in two spring maize (Zea mays L.) genotypes viz., CML-32 (relatively heat tolerant) and LM-11 (relatively heat susceptible), under high temperature stress. High temperature induced greater reduction in dry biomass of LM-1 1 seedlings as compared to those of CML-32. There was a parallel increase in ascorbate peroxidase and glutathione reductase activities in the roots of CML-32 seedlings. However, the activities of catalase and superoxide dismutase decreased and the contents of H202, proline and malonaldialdehyde (MDA) increased in seedlings of both the genotypes. Application of SA (400 µM) led to increased dry biomass in heat stressed CML-32 seedlings. It improved the efficiency of Halliwell-Asada pathway in roots of CML-32 seedlings as was evidenced by the enhanced ascorbate peroxidase and glutathione reductase activities. The activities of catalase and superoxide dismutase increased in both the tissues of LM-11 seedlings, whereas in CML-32, it was only in shoots, after SA application. Peroxidase activity increased in SA treated seedlings of both the genotypes, though the increase was comparatively higher in CML-32. The contents of H₂O₂ and MDA decreased and that of proline increased in SA treated seedlings of both the genotypes, under stress conditions. It may be concluded that SA induced differential antioxidant response by upregulating Halliwell-Asada pathway in roots and attaining high POX activity in both the tissues of CML-32 seedlings, under high temperature stress. PMID:27468465

  12. Acid stress adaptation protects saccharomyces cerevisiae from acetic acid-induced programme cell death

    Giannattasio, Sergio; Guaragnella, Nicoletta; Côrte-Real, Manuela; Passarella, Salvatore; Marra, Ersilia

    2005-01-01

    In this work evidence is presented that acid stress adaptation protects Saccharomyces cerevisiae from acetic acid-mediated programmed cell death. Exponential-phase yeast cells, non-adapted or adapted to acid stress by 30 min incubation in rich medium set at pH 3.0 with HCl, have been exposed to increasing concentrations of acetic acid and time course changes of cell viability have been assessed. Adapted cells, in contrast to non-adapted cells, when exposed to 80 mM acetic acid for 200 min ...

  13. Fusaric acid induces mitochondrial stress in human hepatocellular carcinoma (HepG2) cells.

    Sheik Abdul, Naeem; Nagiah, Savania; Chuturgoon, Anil A

    2016-09-01

    Fusarium spp are common contaminants of maize and produce many mycotoxins, including the fusariotoxin fusaric acid (FA). FA is a niacin related compound, chelator of divalent cations, and mediates toxicity via oxidative stress and possible mitochondrial dysregulation. Sirtuin 3 (SIRT3) is a stress response deacetylase that maintains proper mitochondrial function. We investigated the effect of FA on SIRT3 and oxidative and mitochondrial stress pathways in the hepatocellular carcinoma (HepG2) cell line. We determined FA toxicity (24 h incubation; IC50 = 104 μg/ml) on mitochondrial output, cellular and mitochondrial stress responses, mitochondrial biogenesis and markers of cell death using spectrophotometry, luminometry, qPCR and western blots. FA caused a dose dependent decrease in metabolic activity along with significant depletion of intracellular ATP. FA induced a significant increase in lipid peroxidation, despite up-regulation of the antioxidant transcription factor, Nrf2. FA significantly decreased expression of SIRT3 mRNA with a concomitant decrease in protein expression. Lon protease was also significantly down-regulated. FA induced aberrant mitochondrial biogenesis as evidenced by significantly decreased protein expressions of: PGC-1α, p-CREB, NRF1 and HSP70. Finally, FA activated apoptosis as noted by the significantly increased activity of caspases 3/7 and also induced cellular necrosis. This study provides insight into the molecular mechanisms of FA (a neglected mycotoxin) induced hepatotoxicity. PMID:27390038

  14. Fresh green tea and gallic acid ameliorate oxidative stress in kainic acid-induced status epilepticus.

    Huang, Hsiao-Ling; Lin, Chih-Cheng; Jeng, Kee-Ching G; Yao, Pei-Wun; Chuang, Lu-Te; Kuo, Su-Ling; Hou, Chien-Wei

    2012-03-01

    Green tea is one of the most-consumed beverages due to its taste and antioxidative polyphenols. However, the protective effects of green tea and its constituent, gallic acid (GA), against kainic acid (KA)-induced seizure have not been studied. We investigated the effect of fresh green tea leaf (GTL) and GA on KA-induced neuronal injury in vivo and in vitro. The results showed that GTL and GA reduced the maximal seizure classes, predominant behavioral seizure patterns, and lipid peroxidation in male FVB mice with status epilepticus (SE). GTL extract and GA provided effective protection against KA-stressed PC12 cells in a dose-dependent manner. In the protective mechanism study, GTL and GA decreased Ca(2+) release, ROS, and lipid peroxidation from KA-stressed PC12 cells. Western blot results revealed that mitogen-activated protein kinases (MAPKs), RhoA, and COX-2 expression were increased in PC12 cells under KA stress, and expression of COX-2 and p38 MAPK, but not RhoA, was significantly reduced by GTL and GA. Furthermore, GTL and GA were able to reduce PGE(2) production from KA-stressed PC12 cells. Taken together, the results showed that GTL and GA provided neuroprotective effects against excitotoxins and may have a clinical application in epilepsy. PMID:22324774

  15. Pseudomonas putida response in membrane bioreactors under salicylic acid-induced stress conditions

    Collado, Sergio; Rosas, Irene; González, Elena; Gutierrez-Lavin, Antonio; Diaz, Mario, E-mail: mariodiaz@uniovi.es

    2014-02-01

    Highlights: • MBR under feed-induced stress conditions: starvation and changing feeding conditions. • High capacity of MBR to withstand high variations in feed loads. • Slow biofilm formation under starvation conditions during the first days. • Observed growth of P. putida for substrate to microorganism ratio higher than 0.6 g/g. • Maximum specific growth rate and growth yield values of around 37.5 h{sup −1} and 0.5 g/g. - Abstract: Starvation and changing feeding conditions are frequently characteristics of wastewater treatment plants. They are typical causes of unsteady-state operation of biological systems and provoke cellular stress. The response of a membrane bioreactor functioning under feed-induced stress conditions is studied here. In order to simplify and considerably amplify the response to stress and to obtain a reference model, a pure culture of Pseudomonas putida was selected instead of an activated sludge and a sole substrate (salicylic acid) was employed. The system degraded salicylic acid at 100–1100 mg/L with a high level of efficiency, showed rapid acclimation without substrate or product inhibition phenomena and good stability in response to unsteady states caused by feed variations. Under starvation conditions, specific degradation rates of around 15 mg/g h were achieved during the adaptation of the biomass to the new conditions and no biofilm formation was observed during the first days of experimentation using an initial substrate to microorganisms ratio lower than 0.1. When substrate was added to the reactor as pulses resulting in rapidly changing concentrations, P. putida growth was observed only for substrate to microorganism ratios higher than 0.6, with a maximum Y{sub X/S} of 0.5 g/g. Biofilm development under changing feeding conditions was fast, biomass detachment only being significant for biomass concentrations on the membrane surface that were higher than 16 g/m{sup 2}.

  16. Pseudomonas putida response in membrane bioreactors under salicylic acid-induced stress conditions

    Highlights: • MBR under feed-induced stress conditions: starvation and changing feeding conditions. • High capacity of MBR to withstand high variations in feed loads. • Slow biofilm formation under starvation conditions during the first days. • Observed growth of P. putida for substrate to microorganism ratio higher than 0.6 g/g. • Maximum specific growth rate and growth yield values of around 37.5 h−1 and 0.5 g/g. - Abstract: Starvation and changing feeding conditions are frequently characteristics of wastewater treatment plants. They are typical causes of unsteady-state operation of biological systems and provoke cellular stress. The response of a membrane bioreactor functioning under feed-induced stress conditions is studied here. In order to simplify and considerably amplify the response to stress and to obtain a reference model, a pure culture of Pseudomonas putida was selected instead of an activated sludge and a sole substrate (salicylic acid) was employed. The system degraded salicylic acid at 100–1100 mg/L with a high level of efficiency, showed rapid acclimation without substrate or product inhibition phenomena and good stability in response to unsteady states caused by feed variations. Under starvation conditions, specific degradation rates of around 15 mg/g h were achieved during the adaptation of the biomass to the new conditions and no biofilm formation was observed during the first days of experimentation using an initial substrate to microorganisms ratio lower than 0.1. When substrate was added to the reactor as pulses resulting in rapidly changing concentrations, P. putida growth was observed only for substrate to microorganism ratios higher than 0.6, with a maximum YX/S of 0.5 g/g. Biofilm development under changing feeding conditions was fast, biomass detachment only being significant for biomass concentrations on the membrane surface that were higher than 16 g/m2

  17. Antagonistic rhizobacteria and jasmonic acid induce resistance against tomato bacterial spot

    Hélvio Gledson Maciel Ferraz

    2015-12-01

    Full Text Available AbstractTomato bacterial spot on tomato may be caused by four species of Xanthomonas and among them X. gardneri(Xg is the most destructive one, especially in areas irrigated using a center pivot system in Minas Gerais state and the midwest region of Brazil. Due to the ineffectiveness of chemical control and the lack of cultivars with high levels of genetic resistance, this study investigated the potential of three antagonists (Streptomyces setonii (UFV618, Bacillus cereus (UFV592 and Serratia marcescens (UFV252, and the hormone jasmonic acid (JA as a positive control, to reduce bacterial spot symptoms and to potentiate defense enzymes in the leaves of tomato plants infected by Xg. Tomato seeds were microbiolized with each antagonist, and the soil was drenched with these bacteria. The plants were sprayed with JA 48 h before Xginoculation. The final average severity on the tomato plants was reduced by 29.44, 59.26 and 61.33% in the UFV592, UFV618 and JA treatments, respectively. The UFV618 antagonist was as effective as JA in reducing bacterial spot symptoms on tomatoes, which can be explained by the greater activities of defense enzymes that are commonly involved in host resistance against bacterial diseases. These results suggest that JA and the UFV618 antagonist can be used in the integrated management of bacterial spot on tomatoes.

  18. Jasmonic acid induced resistance in grapevines to a root and leaf feeder.

    Omer, A D; Thaler, J S; Granett, J; Karban, R

    2000-06-01

    We investigated the effects of induced resistance to the folivore Pacific spider mite, Tetranychus pacificus McGregor (Acari: Tetranychidae), as well as the root-feeding grape phylloxera Daktulosphaira vitifoliae (Fitch) (Homoptera: Phylloxeridae) in grapevines using exogenous applications of the natural plant inducer, jasmonic acid. Foliar jasmonic acid application at concentrations that caused no phytotoxicity significantly reduced the performance of both herbivores. There were less than half as many eggs produced by spider mites feeding on the induced leaves compared with control grapevine leaves. Induction reduced the numbers of phylloxera eggs and nymphal instars by approximately threefold and twofold, respectively, on induced compared with control grapevine roots. The negative demographic effects of jasmonic acid application appeared to be caused by changes in fecundity for the Pacific spider mite, and possibly changes in development rate and fecundity for grape phylloxera. PMID:10902339

  19. Salicylic acid induced physiological and biochemical changes in wheat under drought stress conditions

    Experiment for finding the effect of pre-soaking of wheat seeds varieties, viz Wafaq-2001 and Punjab-96, in salicylic acid (SA) solution on the drought tolerance of wheat, revealed increase in the total biomass and grain yield per plant as well as in spikes per plant, 100 seed weight, proline, total soluble sugars, membrane stability index (MSI), superoxide dismutase (SOD) and ascorbate peroxidase (APOX) activity in both the tested varieties. The yield increase in drought tolerant variety Wafaq-2001 was more as compared to drought sensitive Punjab-96. Results signify the role of SA in regulating the drought response of wheat and that SA could be seed primed and used as a potential growth regulator under drought stress conditions. (author)

  20. Nitric Oxide Mediates 5-Aminolevulinic Acid-Induced Antioxidant Defense in Leaves of Elymus nutans Griseb. Exposed to Chilling Stress.

    Juanjuan Fu

    Full Text Available Nitric oxide (NO and 5-aminolevulinic acid (ALA are both extremely important signalling molecules employed by plants to control many aspects of physiology. In the present study, the role of NO in ALA-induced antioxidant defense in leaves of two sources of Elymus nutans Griseb. (Damxung, DX and Zhengdao, ZD was investigated. Chilling stress enhanced electrolyte leakage, accumulation of malondialdehyde (MDA, hydrogen peroxide (H2O2 and superoxide radical in two E. nutans, which were substantially alleviated by exogenous ALA and NO application. Pretreatment with NO scavenger PTIO or NOS inhibitor L-NNA alone and in combination with ALA induced enhancements in electrolyte leakage and the accumulation of MDA, H2O2 and superoxide radical in leaves of DX and ZD exposed to chilling stress, indicating that the inhibition of NO biosynthesis reduced the chilling resistance of E. nutans and the ALA-enhanced chilling resistance. Further analyses showed that ALA and NO enhanced antioxidant defense and activated plasma membrane (PM H+-ATPase and decreased the accumulation of ROS induced by chilling stress. A pronounced increase in nitric oxide synthase (NOS activity and NO release by exogenous ALA treatment was found in chilling-resistant DX plants exposed to chilling stress, while only a little increase was observed in chilling-sensitive ZD. Furthermore, inhibition of NO accumulation by PTIO or L-NNA blocked the protective effect of exogenous ALA, while both exogenous NO treatment and inhibition of endogenous NO accumulation did not induce ALA production. These results suggested that NO might be a downstream signal mediating ALA-induced chilling resistance in E. nutans.

  1. GLYCINE BETAINE AND SALICYLIC ACID INDUCED MODIFICATION IN PRODUCTIVITY OF TWO DIFFERENT CULTIVARS OF WHEAT GROWN UNDER WATER STRESS

    Heshmat S. Aldesuquy; Mohamed A. Abbas; Samy. A. Abo- Hamed; Abeer H. Elhakem; Saeed S. Alsokari

    2012-01-01

    A pot experiment was conducted to evaluate the beneficial effect of foliar application of glycine betaine (10mM), grain presoaking in salicylic acid (0.05 M) and their interaction on drought tolerance of two wheat (Triticum aestivum L.) cultivars (sensitive, Sakha 94 and resistant, Sakha 93). Water stress decreased wheat yield components (spike length, number of spikelets / main spike, 100 kernel weight, grain number / spike, grain yield / spike, grain yield / plant, straw yield / plant, crop...

  2. Glycine betaine and salicylic acid induced modification in productivity of two different cultivars of wheat grown under water stress

    Heshmat S. Aldesuquy

    2012-05-01

    Full Text Available A pot experiment was conducted to evaluate the beneficial effect of foliar application of glycine betaine (10mM, grain presoaking in salicylic acid (0.05 M and their interaction on drought tolerance of two wheat (Triticum aestivum L. cultivars (sensitive, Sakha 94 and resistant, Sakha 93. Water stress decreased wheat yield components (spike length, number of spikelets / main spike, 100 kernel weight, grain number / spike, grain yield / spike, grain yield / plant, straw yield / plant, crop yield / plant, harvest, mobilization and crop indices and the biochemical aspects of grains(grain biomass, carbohydrates, total protein, total phosphorus, ions content and amino acids in both wheat cultivars. The applied chemicals appeared to alleviate the negative effects of water stress on wheat productivity (particularly the sensitive one and the biochemical aspects of yielded grains. The effect was more pronounced with GB+SA treatment. This improvement would result from the repairing effect of the provided chemicals on growth and metabolism of wheat plants grown under water deficit condition. In response to the applied water stress and the used chemicals, the grain yield of the sensitive and resistant wheat cultivars was strongly correlated with all the estimated yield components (shoot length, spike length, plant height, main spike weight, number of spikelets per main spike, 100 kernel weight, grain number per spike, grain weight per plant, straw weight per plant, crop yield per plant, harvest, mobilization and crop indices.

  3. The role of amino acid-induced mammalian target of rapamycin complex 1(mTORC1) signaling in insulin resistance.

    Yoon, Mee-Sup; Choi, Cheol Soo

    2016-01-01

    Mammalian target of rapamycin (mTOR) controls cell growth and metabolism in response to nutrients, energy, and growth factors. Recent findings have placed the lysosome at the core of mTOR complex 1 (mTORC1) regulation by amino acids. Two parallel pathways, Rag GTPase-Ragulator and Vps34-phospholipase D1 (PLD1), regulate mTOR activation on the lysosome. This review describes the recent advances in understanding amino acid-induced mTOR signaling with a particular focus on the role of mTOR in insulin resistance. PMID:27534530

  4. Free fatty acid-induced hepatic insulin resistance is attenuated following lifestyle intervention in obese individuals with impaired glucose tolerance

    Haus, Jacob M; Solomon, Thomas; Marchetti, Christine M;

    2010-01-01

    The objective of the study was to examine the effects of an exercise/diet lifestyle intervention on free fatty acid (FFA)-induced hepatic insulin resistance in obese humans.......The objective of the study was to examine the effects of an exercise/diet lifestyle intervention on free fatty acid (FFA)-induced hepatic insulin resistance in obese humans....

  5. Long-term fatty liver-induced insulin resistance in orotic acid-induced nonalcoholic fatty liver rats.

    Han, Xiuqing; Liu, Chunhua; Xue, Yong; Wang, Jingfeng; Xue, Changhu; Yanagita, Teruyoshi; Gao, Xiang; Wang, Yuming

    2016-01-01

    We investigated whether fatty liver preceded insulin resistance or vice versa using a long-term orotic acid (OA)-induced nonalcoholic fatty liver disease (NAFLD) model without the confounding effects of obesity and hyperlipidemia and explored the role of the liver in insulin resistance. Male Wistar rats were fed with or without OA supplementation for 30, 60, and 90 days. The NAFLD group showed increased liver lipid at 30, 60, and 90 days; glucose intolerance was noted at 60 and 90 days. Furthermore, partial liver proteins and gene expressions related to upstream signaling of insulin were decreased. However, the liver glycogen content was elevated, and gluconeogenesis genes expressions were obviously decreased at 90 days. The occurrence of fatty liver preceded insulin resistance in OA-induced NAFLD without the interference of obesity and hyperlipidemia, and hepatic insulin resistance may not play a conclusive role in insulin resistance in this model. PMID:26775542

  6. Postharvest Treatment with β-Aminobutyric Acid Induces Resistance Against Dry Rot Caused by Fusarium sulphureum in Potato Tuber

    YIN Yan; LI Yong-cai; BI Yang; CHEN Song-jiang; LI Ying-chao; YUAN Li; WANG Yi; WANG Di

    2010-01-01

    The effectiveness of postharvest β-aminobutyric acid(BABA)treatment was studied for inducing resistance against dry rot caused by Fusarium sulphureum in tubers and slices of two potato cultivars(resistant cultivar Shepody and susceptible cultivar Xindaping).The results showed that BABA at 100 mmol L-1 significantly reduced lesion diameter in inoculated both tubers and slices.The chemical at 100 mmol L-1 showed an effective reduction in infection ability of F.sulphureum inoculated 48 and 72 h after treatment in slices of resistant cultivar,and 72 and 96 h in susceptible ones.BABA increased the activitives of peroxidase(POD),polyphenoloxidase(PPO)and phenylalanine ammonialyase(PAL),and accumulated the contents of lignin,flavonoids and phenolics in slices.The resistant cultivar had a stronger resistant response than the susceptible one.These findings suggest that the BABA treatment can induce the resistance in potato tubers,however,the inducing degree depends on the original level of resistance present in each cultivar.

  7. Genetic modification of alternative respiration in Nicotiana benthamiana affects basal and salicylic acid-induced resistance to potato virus X

    Verchot-Lubicz Jeanmarie

    2011-02-01

    Full Text Available Abstract Background Salicylic acid (SA regulates multiple anti-viral mechanisms, including mechanism(s that may be negatively regulated by the mitochondrial enzyme, alternative oxidase (AOX, the sole component of the alternative respiratory pathway. However, studies of this mechanism can be confounded by SA-mediated induction of RNA-dependent RNA polymerase 1, a component of the antiviral RNA silencing pathway. We made transgenic Nicotiana benthamiana plants in which alternative respiratory pathway capacity was either increased by constitutive expression of AOX, or decreased by expression of a dominant-negative mutant protein (AOX-E. N. benthamiana was used because it is a natural mutant that does not express a functional RNA-dependent RNA polymerase 1. Results Antimycin A (an alternative respiratory pathway inducer and also an inducer of resistance to viruses and SA triggered resistance to tobacco mosaic virus (TMV. Resistance to TMV induced by antimycin A, but not by SA, was inhibited in Aox transgenic plants while SA-induced resistance to this virus appeared to be stronger in Aox-E transgenic plants. These effects, which were limited to directly inoculated leaves, were not affected by the presence or absence of a transgene constitutively expressing a functional RNA-dependent RNA polymerase (MtRDR1. Unexpectedly, Aox-transgenic plants infected with potato virus X (PVX showed markedly increased susceptibility to systemic disease induction and virus accumulation in inoculated and systemically infected leaves. SA-induced resistance to PVX was compromised in Aox-transgenic plants but plants expressing AOX-E exhibited enhanced SA-induced resistance to this virus. Conclusions We conclude that AOX-regulated mechanisms not only play a role in SA-induced resistance but also make an important contribution to basal resistance against certain viruses such as PVX.

  8. Involvement of ethylene in gibberellic acid-induced sulfur assimilation, photosynthetic responses, and alleviation of cadmium stress in mustard.

    Masood, Asim; Khan, M Iqbal R; Fatma, Mehar; Asgher, Mohd; Per, Tasir S; Khan, Nafees A

    2016-07-01

    The role of gibberellic acid (GA) or sulfur (S) in stimulation of photosynthesis is known. However, information on the involvement of ethylene in GA-induced photosynthetic responses and cadmium (Cd) tolerance is lacking. This work shows that ethylene is involved in S-assimilation, photosynthetic responses and alleviation of Cd stress by GA in mustard (Brassica juncea L.). Plants grown with 200 mg Cd kg(-1) soil were less responsive to ethylene despite high ethylene evolution and showed photosynthetic inhibition. Plants receiving 10 μM GA spraying plus 100 mg S kg(-1) soil supplementation exhibited increased S-assimilation and photosynthetic responses under Cd stress. Application of GA plus S decreased oxidative stress of plants grown with Cd and limited stress ethylene formation to the range suitable for promoting sulfur use efficiency (SUE), glutathione (GSH) production and photosynthesis. The role of ethylene in GA-induced S-assimilation and reversal of photosynthetic inhibition by Cd was substantiated by inhibiting ethylene biosynthesis with the use of aminoethoxyvinylglycine (AVG). The suppression of S-assimilation and photosynthetic responses by inhibiting ethylene in GA plus S treated plants under Cd stress indicated the involvement of ethylene in GA-induced S-assimilation and Cd stress alleviation. The outcome of the study is important to unravel the interaction between GA and ethylene and their role in Cd tolerance in plants. PMID:26998941

  9. Interleukin-6 deficiency reduces the brain inflammatory response and increases oxidative stress and neurodegeneration after kainic acid-induced seizures

    Penkowa, M; Molinero, A; Carrasco, J;

    2001-01-01

    and were killed six days later. Morphological damage to the hippocampal field CA1-CA3 was seen after kainic acid treatment. Reactive astrogliosis and microgliosis were prominent in kainic acid-injected normal mice hippocampus, and clear signs of increased oxidative stress were evident. Thus...... was caused by kainic acid, as revealed by terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate-biotin nick end labeling and interleukin-1beta converting enzyme/Caspase-1 stainings. In kainic acid-injected interleukin-6 null mice, reactive astrogliosis and microgliosis were reduced, while...... morphological hippocampal damage, oxidative stress and apoptotic neuronal death were increased. Since metallothionein-I+II levels were lower, and those of inducible nitric oxide synthase higher, these concomitant changes are likely to contribute to the observed increased oxidative stress and neuronal death...

  10. Endoplasmic reticulum stress involved in high-fat diet and palmitic acid-induced vascular damages and fenofibrate intervention

    Fenofibrate (FF) is widely used to lower blood lipids in clinical practice, but whether its protective effect on endothelium-dependent vasodilatation (EDV) in thoracic aorta is related with endoplasmic reticulum (ER) stress remains unknown. In this study, female Sprauge Dawley rats were divided into standard chow diets (SCD), high-fat diets (HFD) and HFD plus FF treatment group (HFD + FF) randomly. The rats of latter two groups were given HFD feeding for 5 months, then HFD + FF rats were treated with FF (30 mg/kg, once daily) via gavage for another 2 months. The pathological and tensional changes, protein expression of eNOS, and ER stress related genes in thoracic aorta were measured. Then impacts of palmitic acid (PA) and FF on EDV of thoracic aorta from normal female SD rats were observed. Ultimately the expression of ER stress related genes were assessed in primary mouse aortic endothelial cells (MAEC) treated by fenofibric acid (FA) and PA. We found that FF treatment improved serum lipid levels and pathological changes in thoracic aorta, accompanied with decreased ER stress and increased phosphorylation of eNOS. FF pretreatment also improved EDV impaired by different concentrations of PA treatment. The dose- and time-dependent inhibition of cell proliferation by PA were inverted by FA pretreatment. Phosphorylation of eNOS and expression of ER stress related genes were all inverted by FA pretreatment in PA-treated MAEC. Our findings show that fenofibrate recovers damaged EDV by chronic HFD feeding and acute stimulation of PA, this effect is related with decreased ER stress and increased phosphorylation of eNOS. - Highlights: • Fenofibrate treatment improved pathological changes in thoracic aorta by chronic high-fat-diet feeding. • Fenofibrate pretreatment improved endothelium-dependent vasodilation impaired by different concentrations of palmitic acid. • The inhibition of proliferation in endothelial cells by palmitic acid were inverted by fenofibric

  11. Endoplasmic reticulum stress involved in high-fat diet and palmitic acid-induced vascular damages and fenofibrate intervention

    Lu, Yunxia, E-mail: wwwdluyx@sina.com [Department of Biochemistry and Molecular Biology, Anhui Medical University, Hefei, Anhui 230032 (China); The Comprehensive Laboratory, Anhui Medical University, Hefei, Anhui 230032 (China); Cheng, Jingjing [Department of Biochemistry and Molecular Biology, Anhui Medical University, Hefei, Anhui 230032 (China); Chen, Li [Department of Biochemistry and Molecular Biology, Anhui Medical University, Hefei, Anhui 230032 (China); Department of Medical Laboratory, Anhui Provincial Hospital, Hefei, Anhui 230001 (China); Li, Chaofei; Chen, Guanjun [Department of Biochemistry and Molecular Biology, Anhui Medical University, Hefei, Anhui 230032 (China); Gui, Li [The Comprehensive Laboratory, Anhui Medical University, Hefei, Anhui 230032 (China); Shen, Bing [Department of Physiology, Anhui Medical University, Hefei, Anhui 230032 (China); Zhang, Qiu [Department of Endocrinology, First Affiliated Hospital of Anhui Medical University, Hefei, Anhui 230022 (China)

    2015-02-27

    Fenofibrate (FF) is widely used to lower blood lipids in clinical practice, but whether its protective effect on endothelium-dependent vasodilatation (EDV) in thoracic aorta is related with endoplasmic reticulum (ER) stress remains unknown. In this study, female Sprauge Dawley rats were divided into standard chow diets (SCD), high-fat diets (HFD) and HFD plus FF treatment group (HFD + FF) randomly. The rats of latter two groups were given HFD feeding for 5 months, then HFD + FF rats were treated with FF (30 mg/kg, once daily) via gavage for another 2 months. The pathological and tensional changes, protein expression of eNOS, and ER stress related genes in thoracic aorta were measured. Then impacts of palmitic acid (PA) and FF on EDV of thoracic aorta from normal female SD rats were observed. Ultimately the expression of ER stress related genes were assessed in primary mouse aortic endothelial cells (MAEC) treated by fenofibric acid (FA) and PA. We found that FF treatment improved serum lipid levels and pathological changes in thoracic aorta, accompanied with decreased ER stress and increased phosphorylation of eNOS. FF pretreatment also improved EDV impaired by different concentrations of PA treatment. The dose- and time-dependent inhibition of cell proliferation by PA were inverted by FA pretreatment. Phosphorylation of eNOS and expression of ER stress related genes were all inverted by FA pretreatment in PA-treated MAEC. Our findings show that fenofibrate recovers damaged EDV by chronic HFD feeding and acute stimulation of PA, this effect is related with decreased ER stress and increased phosphorylation of eNOS. - Highlights: • Fenofibrate treatment improved pathological changes in thoracic aorta by chronic high-fat-diet feeding. • Fenofibrate pretreatment improved endothelium-dependent vasodilation impaired by different concentrations of palmitic acid. • The inhibition of proliferation in endothelial cells by palmitic acid were inverted by fenofibric

  12. Nonesterified Fatty Acid-Induced Endoplasmic Reticulum Stress in Cattle Cumulus Oocyte Complexes Alters Cell Metabolism and Developmental Competence.

    Sutton-McDowall, Melanie L; Wu, Linda L Y; Purdey, Malcolm; Abell, Andrew D; Goldys, Ewa M; MacMillan, Keith L; Thompson, Jeremy G; Robker, Rebecca L

    2016-01-01

    Reduced oocyte quality has been associated with poor fertility of high-performance dairy cows during peak lactation, due to negative energy balance. We examined the role of nonesterified fatty acids (NEFAs), known to accumulate within follicular fluid during under- and overnutrition scenarios, in causing endoplasmic reticulum (ER) stress of in vitro maturated cattle cumulus-oocyte complexes (COCs). NEFA concentrations were: palmitic acid (150 μM), oleic acid (200 μM), and steric acid (75 μM). Abattoir-derived COCs were randomly matured for 24 h in the presence of NEFAs and/or an ER stress inhibitor, salubrinal. Total and hatched blastocyst yields were negatively impacted by NEFA treatment compared with controls, but this was reversed by salubrinal. ER stress markers, activating transcription factor 4 (Atf4) and heat shock protein 5 (Hspa5), but not Atf6, were significantly up-regulated by NEFA treatment within whole COCs but reversed by coincubation with salubrinal. Likewise, glucose uptake and lactate production, measured in spent medium samples, showed a similar pattern, suggesting that cumulus cell metabolism is sensitive to NEFAs via an ER stress-mediated process. In contrast, while mitochondrial DNA copy number was recovered in NEFA-treated oocytes, oocyte autofluorescence of the respiratory chain cofactor, FAD, was lower following NEFA treatment of COCs, and this was not reversed by salubrinal, suggesting the negative impact was via reduced mitochondrial function. These results reveal the significance of NEFA-induced ER stress on bovine COC developmental competence, revealing a potential therapeutic target for improving oocyte quality during peak lactation. PMID:26658709

  13. Astaxanthin improves behavioral disorder and oxidative stress in prenatal valproic acid-induced mice model of autism.

    Al-Amin, Md Mamun; Rahman, Md Mahbubur; Khan, Fazlur Rahman; Zaman, Fahmida; Mahmud Reza, Hasan

    2015-06-01

    Prenatal exposure to valproic acid on gestational day 12.5 may lead to the impaired behavior in the offspring, which is similar to the human autistic symptoms. To the contrary, astaxanthin shows neuroprotective effect by its antioxidant mechanism. We aimed to (i) develop mice model of autism and (ii) investigate the effect of astaxanthin on such model animals. Valproic acid (600 mg/kg) was administered intraperitoneally to the pregnant mice on gestational day 12.5. Prenatal valproic acid-exposed mice were divided into 2 groups on postnatal day 25 and astaxanthin (2mg/kg) was given to the experimental group (VPA_AST, n=10) while saline was given to the control group (VPA, n=10) for 4 weeks. Behavioral test including social interaction, open field and hot-plate were conducted on postnatal day 25 and oxidative stress markers such as lipid peroxidation, advanced protein oxidation product, nitric oxide, glutathione, and activity of superoxide dismutase and catalase were estimated on postnatal day 26 to confirm mice model of autism and on postnatal day 56 to assess the effect of astaxanthin. On postnatal day 25, prenatal valproic acid-exposed mice exhibited (i) delayed eye opening (ii) longer latency to respond painful stimuli, (iii) poor sociability and social novelty and (iv) high level of anxiety. In addition, an increased level of oxidative stress was found by determining different oxidative stress markers. Treatment with astaxanthin significantly (pfeatures. Astaxanthin improves the impaired behavior in animal model of autism presumably by its antioxidant activity. PMID:25732953

  14. γ-Aminobutyric acid induces resistance against Penicillium expansum by priming of defence responses in pear fruit.

    Yu, Chen; Zeng, Lizhen; Sheng, Kuang; Chen, Fangxia; Zhou, Tao; Zheng, Xiaodong; Yu, Ting

    2014-09-15

    The results from this study showed that treatment with γ-aminobutyric acid (GABA), at 100-1000 μg/ml, induced strong resistance against blue mould rot caused by Penicillium expansum in pear fruit. Moreover, the activities of five defence-related enzymes (including chitinase, β-1,3-glucanase, phenylalnine ammonialyase, peroxidase and polyphenol oxidase) and the expression of these corresponding genes were markedly and/or promptly enhanced in the treatment with GABA and inoculation with P. expansum compared with those that were treated with GABA or inoculated with pathogen alone. In addition, the treatment of pear with GABA had little adverse effect on the edible quality of the fruit. To the best of our knowledge, this is the first report that GABA can effectively reduce fungal disease of harvested fruit. Its mechanisms may be closely correlated with the induction of fruit resistance by priming activation and expression of defence-related enzymes and genes upon challenge with pathogen. PMID:24767023

  15. Abscisic acid-induced rearrangement of intracellular structures associated with freezing and desiccation stress tolerance in the liverwort Marchantia polymorpha.

    Akter, Khaleda; Kato, Masahiro; Sato, Yuki; Kaneko, Yasuko; Takezawa, Daisuke

    2014-09-15

    The plant growth regulator abscisic acid (ABA) is known to be involved in triggering responses to various environmental stresses such as freezing and desiccation in angiosperms, but little is known about its role in basal land plants, especially in liverworts, representing the earliest land plant lineage. We show here that survival rate after freezing and desiccation of Marchantia polymorpha gemmalings was increased by pretreatment with ABA in the presence of increasing concentrations of sucrose. ABA treatment increased accumulation of soluble sugars in gemmalings, and sugar accumulation was further increased by addition of sucrose to the culture medium. ABA treatment of gemmalings also induced accumulation of transcripts for proteins with similarity to late embryogenesis abundant (LEA) proteins, which accumulate in association with acquisition of desiccation tolerance in maturing seeds. Observation by light and electron microscopy indicated that the ABA treatment caused fragmentation of vacuoles with increased cytosolic volume, which was more prominent in the presence of a high concentration of external sucrose. ABA treatment also increased the density of chloroplast distribution and remarkably enlarged their volume. These results demonstrate that ABA induces drastic physiological changes in liverwort cells for stress tolerance, accompanied by accumulation of protectants against dehydration and rearrangement and morphological alterations of cellular organelles. PMID:25046754

  16. Sunflower breeding for resistance to abiotic stresses

    Škorić D.

    2009-01-01

    Due to a specific structure of its main organs (root, stem, leaves, head), sunflower can be successfully grown on marginal soils and in semi-arid conditions and it is more resistant to abiotic stresses than other field crops. In sunflower breeding for resistance to abiotic stresses, the greatest progress has been made in selection for drought resistance. Breeders use over 30 different parameters in sunflower screening for drought resistance, with physiological ones being the predominant type....

  17. Perfluorononanoic acid-induced apoptosis in rat spleen involves oxidative stress and the activation of caspase-independent death pathway

    Perfluoroalkyl acid (PFAA)-induced apoptosis has been reported in many cell types. However, minimal information on its mode of action is available. This study explored the possible involvement of apoptotic signaling pathways in a nine-carbon-chain length PFAA-perfluorononanoic acid (PFNA)-induced splenocyte apoptosis. After a 14-day exposure to PFNA, rat spleens showed dose-dependent levels of apoptosis. The production of pro-inflammatory and anti-inflammatory cytokines was significantly increased and decreased, respectively. However, protein levels of tumor necrosis factor receptor 1 (TNFR1), fas-associated protein with death domain (FADD), caspase 8 and caspase 3, which are involved in inflammation-related and caspase-dependent apoptosis, were discordant. Peroxisome proliferator-activated receptors alpha (PPARα) and PPARγ genes expression was up-regulated in rats treated with 3 or 5 mg/kg/day of PFNA, and the level of hydrogen peroxide (H2O2) increased concurrently in rats treated with the highest dose. Moreover, superoxide dismutase (SOD) activity and Bcl-2 protein levels were dramatically decreased in spleens after treatment with 3 and 5 mg/kg/day of PFNA. However, protein levels of Bax were unchanged. Apoptosis-inducing factor (AIF), an initiator of caspase-independent apoptosis, was significantly increased in all PFNA-dosed rats. Thus, oxidative stress and the activation of a caspase-independent apoptotic signaling pathway contributed to PFNA-induced apoptosis in rat splenocytes.

  18. Oxidative stress-driven mechanisms of nordihydroguaiaretic acid-induced apoptosis in FL5.12 cells

    Nordihydroguaiaretic acid (NDGA), a general lipoxygenase (LOX) enzyme inhibitor, induces apoptosis independently of its activity as a LOX inhibitor in murine pro-B lymphocytes (FL.12 cells) by a mechanism that is still not fully understood. Glutathione depletion, oxidative processes and mitochondrial depolarization appear to contribute to the apoptosis induced by NDGA. The current data demonstrate that NDGA (20 μM)-induced apoptosis in FL5.12 cells is partially protected by N-acetylcysteine (NAC) (10 mM) and dithiothreitol (DTT) (500 μM) pretreatment, confirming a role for oxidative processes. In addition, the treatment of FL5.12 cells with NDGA led to an increase in phosphorylation and activation of the MAP kinases ERK, JNK and p38. Although pretreatment with ERK inhibitors (PD98059 or U0126) abolished ERK phosphorylation in response to NDGA, neither inhibitor had any effect on NDGA-induced apoptosis. SP600125, a JNK inhibitor, did not have any effect on NDGA-induced phosphorylation of JNK nor apoptosis. Pretreatment with the p38 inhibitor SB202190 attenuated NDGA-induced apoptosis by 30% and also abolished p38 phosphorylation, compared to NDGA treatment alone. NAC, but not DTT, also decreased the phosphorylation of p38 and JNK supporting a role for oxidative processes in activating these kinases. Neither NAC nor DTT blocked the phosphorylation of ERK suggesting that this activation is not related to oxidative stress. The release of cytochrome c and activation of caspase-3 induced by NDGA were inhibited by NAC. SB202190 slightly attenuated caspase-3 activation and had no effect on the release of cytochrome c. These data suggest that several independent mechanisms, including oxidative reactions, activation of p38 kinase and cytochrome c release contribute to NDGA-induced apoptosis

  19. Exercise, Stress Resistance, and Central Serotonergic Systems

    Greenwood, Benjamin N.; Fleshner, Monika

    2011-01-01

    Voluntary exercise reduces the incidence of stress-related psychiatric disorders in humans and prevents serotonin-dependent behavioral consequences of stress in rodents. Evidence reviewed herein is consistent with the hypothesis that exercise increases stress resistance by producing neuroplasticity at multiple sites of the central serotonergic system, which all help to limit the behavioral impact of acute increases in serotonin during stressor exposure.

  20. LINK BETWEEN OXIDATIVE STRESS AND INSULIN RESISTANCE

    Lan-fang Li; Jian Li

    2007-01-01

    Many studies on oxidative stress, insulin resistance, and antioxidant treatment have shown that increased oxidative stress may accelerate the development of diabetic complications through the excessive glucose and free fatty acids metabolism in diabetic and insulin-resistant states. Many pathogenic mechanisms such as insulin receptor substrate phosphorylation are involved in insulin resistance induced by oxidative stress. And antioxidant treatments can show benefits in animal models of diabetes mellitus and insulin resistance. However, negative evidence from large clinical trials suggests that new and more powerful antioxidants need to be studied to demonstrate whether antioxidants can be effective in treating diabetic complications. Furthermore, it appears that oxidative stress is only one of the factors contributing to diabetic complications. Thus, antioxidant treatment would most likely be more effective if it were coupled with other treatments for diabetic complications.

  1. Stress-induced radiation resistance in yeast

    Cells have evolved biological defense mechanisms that can protect them against a variety of harmful environmental stress including ionizing radiation exposure. The authors have demonstrated that many stresses will induce radiation resistance in yeast. Recently it has become apparent that radiation resistance may be associated with the highly conserved 'stress response' mechanism that confers cellular resistance to a multitude of agents. A universal response to stress is the synthesis of a distinctive set of new proteins, although the function of many of these specific stress proteins is still unknown. One stress protein known to affect thermal tolerance in yeast is HSP104. This report has assessed involvement of HSP104 in the mechanism of radiation resistance by utilizing a yeast strain lacking HSP104 protein (a deletion mutant). It is previously demonstrated that radiation itself will induce yeast cells to develop radiation resistance and that the signal for the response is DNA damage. The nature of the DNA damage signal is important and it is reported that, per unit dose, low linear energy transfer (LET) 60Co gamma-rays induce a greater resistance response compared to high LET neutrons. Here is tested whether the dose rate also influences the signalling efficiency of a radiation inducing dose. (author). 4 refs., 2 figs

  2. ESTIMATION OF INCREASE OF STRESS RESISTANCE AMONG STUDENTS

    Drobysheva O. M.

    2015-01-01

    By results of the estimation of stress resistance on dynamics of the regulation-adaptive status we can observe, that the autogenic training at the end of one academic year did not cause authentic changes in stress resistance in students with high and low levels of stress resistance. At the same time, it raised stress resistance for persons with a moderate level of stress resistance

  3. MyD88 signaling in the CNS is required for development of fatty acid induced leptin resistance and diet-induced obesity

    Kleinridders, Andre; Schenten, Dominik; Mauer, Jan; Wunderlich, F. Thomas; Okamura, Tomoo; Koenner, A. Christine; Belgardt, Bengt F.; Bruening, Jens C.; Medzhitov, Ruslan

    2009-01-01

    Obesity-associated activation of inflammatory pathways represents a key step in the development of insulin resistance in peripheral organs, partially via activation of TLR-4 signaling by fatty acids. Here we demonstrate that palmitate acting in the central nervous system (CNS) inhibits leptin-induced anorexia and Stat-3 activation. To determine the functional significance of TLR signaling in the CNS in the development of leptin resistance and diet-induced obesity in vivo, we have characterize...

  4. Glucose amplifies fatty acid-induced endoplasmic reticulum stress in pancreatic beta-cells via activation of mTORC1.

    Etti Bachar

    Full Text Available BACKGROUND: Palmitate is a potent inducer of endoplasmic reticulum (ER stress in beta-cells. In type 2 diabetes, glucose amplifies fatty-acid toxicity for pancreatic beta-cells, leading to beta-cell dysfunction and death. Why glucose exacerbates beta-cell lipotoxicity is largely unknown. Glucose stimulates mTORC1, an important nutrient sensor involved in the regulation of cellular stress. Our study tested the hypothesis that glucose augments lipotoxicity by stimulating mTORC1 leading to increased beta-cell ER stress. PRINCIPAL FINDINGS: We found that glucose amplifies palmitate-induced ER stress by increasing IRE1alpha protein levels and activating the JNK pathway, leading to increased beta-cell apoptosis. Moreover, glucose increased mTORC1 activity and its inhibition by rapamycin decreased beta-cell apoptosis under conditions of glucolipotoxicity. Inhibition of mTORC1 by rapamycin did not affect proinsulin and total protein synthesis in beta-cells incubated at high glucose with palmitate. However, it decreased IRE1alpha expression and signaling and inhibited JNK pathway activation. In TSC2-deficient mouse embryonic fibroblasts, in which mTORC1 is constitutively active, mTORC1 regulated the stimulation of JNK by ER stressors, but not in response to anisomycin, which activates JNK independent of ER stress. Finally, we found that JNK inhibition decreased beta-cell apoptosis under conditions of glucolipotoxicity. CONCLUSIONS/SIGNIFICANCE: Collectively, our findings suggest that mTORC1 mediates glucose amplification of lipotoxicity, acting through activation of ER stress and JNK. Thus, mTORC1 is an important transducer of ER stress in beta-cell glucolipotoxicity. Moreover, in stressed beta-cells mTORC1 inhibition decreases IRE1alpha protein expression and JNK activity without affecting ER protein load, suggesting that mTORC1 regulates the beta-cell stress response to glucose and fatty acids by modulating the synthesis and activity of specific

  5. Resistance to ursolic acid-induced apoptosis through involvement of melanogenesis and COX-2/PGE2 pathways in human M4Beu melanoma cancer cells.

    Hassan, Lama; Pinon, Aline; Limami, Youness; Seeman, Josiane; Fidanzi-Dugas, Chloe; Martin, Frederique; Badran, Bassam; Simon, Alain; Liagre, Bertrand

    2016-07-01

    Melanoma is one of the most aggressive forms of cancer with a continuously growing incidence worldwide and is usually resistant to chemotherapy agents, which is due in part to a strong resistance to apoptosis. Previously, we had showed that B16-F0 murine melanoma cells undergoing apoptosis are able to delay their own death induced by ursolic acid (UA), a natural pentacyclic triterpenoid compound. We had demonstrated that tyrosinase and TRP-1 up-regulation in apoptotic cells and the subsequent production of melanin were implicated in an apoptosis resistance mechanism. Several resistance mechanisms to apoptosis have been characterized in melanoma such as hyperactivation of DNA repair mechanisms, drug efflux systems, and reinforcement of survival signals (PI3K/Akt, NF-κB and Raf/MAPK pathways). Otherwise, other mechanisms of apoptosis resistance involving different proteins, such as cyclooxygenase-2 (COX-2), have been described in many cancer types. By using a strategy of specific inhibition of each ways, we suggested that there was an interaction between melanogenesis and COX-2/PGE2 pathway. This was characterized by analyzing the COX-2 expression and activity, the expression of tyrosinase and melanin production. Furthermore, we showed that anti-proliferative and proapoptotic effects of UA were mediated through modulation of multiple signaling pathways including Akt and ERK-1/2 proteins. Our study not only uncovers underlying molecular mechanisms of UA action in human melanoma cancer cells but also suggest its great potential as an adjuvant in treatment and cancer prevention. PMID:27262506

  6. Salicylic acid-induced glutathione status in tomato crop and resistance to root-knot nematode, Meloidogyne incognita (Kofoid & White Chitwood

    Hari C. Meher

    2011-10-01

    Full Text Available Salicylic acid-(SA is a plant defense stimulator. Exogenous application of SA might influence the status of glutathione-(GSH. GSH activates and SA alters the expression of defense genes to modulate plant resistance against pathogens. The fate of GSH in a crop following SA treatment is largely unknown. The SA-induced profiles of free reduced-, free oxidized-(GSSG and protein bound-(PSSG glutathione in tomato crop following foliar treatment of transplant at 5.0-10.0 μg mL–1 were measured by liquid chromatography. Resistance to root-knot nematode, Meloidogyne incognita damaging tomato and crop performance were also evaluated. SA treatment at 5.0-10.0 μg mL–1 to tomato transplants increased GSH, GSSG and PSSG in plant leaf and root, more so in leaf, during crop growth and development. As the fruits ripened, GSH and PSSG increased and GSSG declined. SA reduced the root infection by M. incognita, nematode reproduction and thus, improved the resistance of tomato var. Pusa Ruby, but reduced crop growth and redox status. SA at 5.0 μg mL–1 improved yield and fruit quality. The study firstly linked SA with activation of glutathione metabolism and provided an additional dimension to the mechanism of induced resistance against obligate nematode pathogen. SA increased glutathione status in tomato crop, imparted resistance against M. incognita, augmented crop yield and functional food quality. SA can be applied at 5.0 μg mL–1 for metabolic engineering of tomato at transplanting to combine host-plant resistance and health benefits in formulating a strategic nematode management decision.

  7. Maternal mediation, stress inoculation, and the development of neuroendocrine stress resistance in primates

    Parker, Karen J.; Buckmaster, Christine L.; Sundlass, Karan; Schatzberg, Alan F.; Lyons, David M.

    2006-01-01

    The stress inoculation hypothesis presupposes that brief intermittent stress exposure early in life induces the development of subsequent stress resistance in human and nonhuman primates. Rodent studies, however, suggest a role for maternal care rather than stress exposure per se (i.e., the maternal mediation hypothesis). To investigate these two hypotheses, we examined maternal care and the development of stress resistance after exposure to brief intermittent infant stress (IS), mother–infan...

  8. Mitochondrial genome depletion in human liver cells abolishes bile acid-induced apoptosis: role of the Akt/mTOR survival pathway and Bcl-2 family proteins.

    Marin, Jose J G; Hernandez, Alicia; Revuelta, Isabel E; Gonzalez-Sanchez, Ester; Gonzalez-Buitrago, Jose M; Perez, Maria J

    2013-08-01

    Acute accumulation of bile acids in hepatocytes may cause cell death. However, during long-term exposure due to prolonged cholestasis, hepatocytes may develop a certain degree of chemoresistance to these compounds. Because mitochondrial adaptation to persistent oxidative stress may be involved in this process, here we have investigated the effects of complete mitochondrial genome depletion on the response to bile acid-induced hepatocellular injury. A subline (Rho) of human hepatoma SK-Hep-1 cells totally depleted of mitochondrial DNA (mtDNA) was obtained, and bile acid-induced concentration-dependent activation of apoptosis/necrosis and survival signaling pathways was studied. In the absence of changes in intracellular ATP content, Rho cells were highly resistant to bile acid-induced apoptosis and partially resistant to bile acid-induced necrosis. In Rho cells, both basal and bile acid-induced generation of reactive oxygen species (ROS), such as hydrogen peroxide and superoxide anion, was decreased. Bile acid-induced proapoptotic signals were also decreased, as evidenced by a reduction in the expression ratios Bax-α/Bcl-2, Bcl-xS/Bcl-2, and Bcl-xS/Bcl-xL. This was mainly due to a downregulation of Bax-α and Bcl-xS. Moreover, in these cells the Akt/mTOR pathway was constitutively activated in a ROS-independent manner and remained similarly activated in the presence of bile acid treatment. In contrast, ERK1/2 activation was constitutively reduced and was not activated by incubation with bile acids. In conclusion, these results suggest that impaired mitochondrial function associated with mtDNA alterations, which may occur in liver cells during prolonged cholestasis, may activate mechanisms of cell survival accounting for an enhanced resistance of hepatocytes to bile acid-induced apoptosis. PMID:23597504

  9. Palmitic Acid-Induced Neuron Cell Cycle G2/M Arrest and Endoplasmic Reticular Stress through Protein Palmitoylation in SH-SY5Y Human Neuroblastoma Cells

    Yung-Hsuan Hsiao

    2014-11-01

    Full Text Available Obesity-related neurodegenerative diseases are associated with elevated saturated fatty acids (SFAs in the brain. An increase in SFAs, especially palmitic acid (PA, triggers neuron cell apoptosis, causing cognitive function to deteriorate. In the present study, we focused on the specific mechanism by which PA triggers SH-SY5Y neuron cell apoptosis. We found that PA induces significant neuron cell cycle arrest in the G2/M phase in SH-SY5Y cells. Our data further showed that G2/M arrest is involved in elevation of endoplasmic reticular (ER stress according to an increase in p-eukaryotic translation inhibition factor 2α, an ER stress marker. Chronic exposure to PA also accelerates beta-amyloid accumulation, a pathological characteristic of Alzheimer’s disease. Interestingly, SFA-induced ER stress, G2/M arrest and cell apoptosis were reversed by treatment with 2-bromopalmitate, a protein palmitoylation inhibitor. These findings suggest that protein palmitoylation plays a crucial role in SFA-induced neuron cell cycle G2/M arrest, ER stress and apoptosis; this provides a novel strategy for preventing SFA-induced neuron cell dysfunction.

  10. Fluvoxamine Attenuated Endoplasmic Reticulum Stress-Induced Leptin Resistance

    Hosoi, Toru; Miyahara, Tsuyoshi; Kayano, Takaaki; Yokoyama, Shota; Ozawa, Koichiro

    2012-01-01

    Increasing evidence indicates that endoplasmic reticulum stress (ER stress) is involved in the development of metabolic syndrome. However, pharmacological treatments targeting ER stress are not well understood. In the present study, we found that fluvoxamine, a selective serotonin reuptake inhibitor used for depression, can attenuate ER stress-induced “leptin resistance,” i.e., insensitivity to the anti-obesity hormone leptin. Treatment with tunicamycin, an ER stress-inducing reagent, caused ...

  11. Psychological analysis of stress resistance in professional rescuers

    Sinishina V.M.

    2013-01-01

    The article reveals and systematize the modern approaches of foreign and domestic scholars to the problem of the formation of personal psychological resistance to work stress in rescuers. Revealing the problem of stress through a comprehensive analysis of the literature, the author comes to the conclusion that the problem of the formation of stress resistance in the modern world has dynamic, integrating nature, causing the emergence of new, previously unknown problems in today world which do ...

  12. Study on the Resistance of Cucumber to Temperature Stresses

    Ma Dehua; Pang Jin'an; Huo Zhenrong; Li Shuju; Du Shengli

    2000-01-01

    Four cucumber (Cucumis sativus L. ) inbred lines with different resistances to temperature stress were used in this experiment. The seedlings of line Q10 and Q21 that have high resistance to chilling stress also have high resistance to heat stress. The seedlings of line T94 and T55 that have lower resistance to chilling stress also have lower resistance to heat stress. It seems that the resistance of cucumber seedlings to different temperature stresses was similar. The influences of chilling and heat stress on the germination ability of cucumber seeds were different. Under the chilling stress, the germination percentage decreased less, and the germination velocity decreased more,so the germination index decreased significantly. Under the heat stress, the germination percentage and velocity of the seeds with high resistance decreased less and those of the seeds with lower resistance decreased more. The differences among the lines became more evident under the extreme heat condition. The content of chlorophyll decreased under the different temperature stresses, the content of chlorophyll a decreased more than that of chlorophyll b, so the value of chlorophyll a/b decreased.The temperature stress inhibited the photosynthesis of cucumber seedlings significantly. After chilling or heat treatment, the net photosynthetic rate (Pn) decreased remarkably. With the stomatal conductance (Gs) decreased, the stomatal limited value (Is) decreased, the intercellular CO2 concentration (Ci) increased, and both the apparent quantum efficiencies (AQE) and the carboxylation efficiencies (CE) decreased. Results showed that the non-stomatal factors were the main causes of Pn decrease, and the photosynthetic mechanism was destroyed remarkably.

  13. Mechanisms of yeast resistance to environmental stress 

    Agata Piecuch

    2013-04-01

    Full Text Available Changes in environmental conditions might be a stress factor for yeast cells. There are several mechanisms of stress tolerance, developed by the cell, which activate when the stress appears. Different transcription factors coordinate the expression of stress response genes. Msn2/4p regulate the expression of the general stress response. Heat shock defense involves heat shock proteins (Hsp, controlled by Hsf1p. Osmotic shock induces the MAP kinase cascade (HOG, whereas the oxidative stress response requires the YAP network. Fungicide resistance is mediated mainly by the activity of membrane transporters and changes in the structure of the plasma membrane. 

  14. Overexpression of VOZ2 confers biotic stress tolerance but decreases abiotic stress resistance in Arabidopsis

    Nakai, Yusuke; Fujiwara, Sumire; Kubo, Yasuyuki; Sato, Masa H.

    2013-01-01

    VOZ (vascular plant one zinc-finger protein) is a plant specific one-zinc finger type transcriptional activator, which is highly conserved through land plant evolution. We have previously shown that loss-of-function mutations in VOZ1 and VOZ2 showed increased cold and drought stress tolerances whereas decreased biotic stress resistance in Arabidopsis. Here, we demonstrate that transgenic plants overexpressing VOZ2 impairs freezing and drought stress tolerances but increases resistance to a fu...

  15. Screening for Stress Resistance Mutations in the Mouse

    Wallace S Chick

    2014-09-01

    Full Text Available Longevity is correlated with stress resistance in many animal models. However, previous efforts through the boosting of the antioxidant defense system did not extend life span, suggesting that longevity related stress resistance is mediated by other uncharacterized pathways. We have developed a high-throughput platform for screening and rapid identification of novel genetic mutants in the mouse that are stress-resistant. Selection for resistance to stressors occurs in mutagenized mouse embryonic stem (ES cells, which are carefully treated so as to maintain pluripotency for mouse production. Initial characterization of these mutant ES cells revealed mutations in Pigl, Tiam1, and Rffl, among others. These genes are implicated in glycosylphosphatidylinositol biosynthesis, NADPH oxidase function, and inflammation. These mutants: (1 are resistant to two different oxidative stressors, paraquat and the omission of 2-mercaptoethanol, (2 have reduced levels of endogenous reactive oxygen species (ROS, (3 are capable of generating live mice, and (4 transmit the stress resistance phenotype to the mice. This strategy offers an efficient way to select for new mutants expressing a stress resistance phenotype, to rapidly identify the causative genes, and to develop mice for in vivo studies.

  16. Stress stimulus induced resistance to Cladosporium cucumerinum in cucumber seeding.

    Zhao, Huan; Wang, Bo-Chu; Zhao, Hu-Cheng; Wang, Jing Bo

    2005-07-25

    Up to date, the studies of plant induced resistance have become the focus in plant pathology and physiology. During the course of pathogens penetrating the plant cell, besides of chemical secretion, the pathogens may generate mechanical signal caused by the physical pressure on the plant cell. In the non-host resistance, both the chemical signal and the mechanical stress signal are considered to have contribution to the entire defense reaction acted by the plant. The penetration of pathogen Cladosporium cucumerinum to cucumber is thought to be one of the model in research of plant induced resistance. In the current study, as a mechanical signal elicitor, the appropriate stress stimulus was proved to effectually induce the resistance of cucumber seedling to C. cucumerinum. After the treatment of the stress stimulus on leaves, the activities of resistance-related enzymes were significantly increased, such as phenylanine ammonia lyase (PAL), peroxidase (POD). Also, we found that stress stimulation may cause synthesis of lignin, which acts as the physical barrier to defense the pathogens. The results suggest that stress stimulation may not only enhance ability of the plant cell resistance to pathogen penetration but also elicit the accumulation of pathogens suppression or antimicrobial chemical substance in the plant cell. PMID:16002268

  17. Resistance Responses of Carbon Fiber Cement to Cycled Compressive Stresses

    SHUI Zhonghe; LI Chao; LIAO Weidong

    2005-01-01

    The stress-resistance relationship of carbon fiber cement was studicd. Attention has been paid to explore the improvement of the stress-resistance sensitivity under cycled stress restriction. The prismy carbon fiber cement sensors were pre-fabricated. The factors such as contents of carbon fibers, silica fume, dispersant and the w/ c were taken into account. The electrical resistance variations with the dynamic and static loads were simulated using a strain-controlled test machine. The test results show that there is an optimal fiber content, with which the compression-sensitivity achieves a high level. The addition of silica fume can improve the sensitivity. Urder the optimal test conditions, the measured resistances can greatly correspond with the changes of the load.

  18. Fluvoxamine attenuated endoplasmic reticulum stress-induced leptin resistance

    Toru eHosoi

    2012-01-01

    Full Text Available Increasing evidence indicates that endoplasmic reticulum stress (ER stress is involved in the development of metabolic syndrome. However, pharmacological treatments targeting ER stress are not well understood. In the present study, we found that fluvoxamine, a selective serotonin reuptake inhibitor used for depression, can attenuate ER stress-induced leptin resistance, i.e. insensitivity to the anti-obesity hormone leptin. Treatment with tunicamycin, an ER stress-inducing reagent, caused cell death which was significantly inhibited by fluvoxamine. Leptin activates JAK2-STAT3 signaling. ER stress caused an impairment of leptin-induced STAT3 phosphorylation which was reversed by fluvoxamine. Fluvoxamine would be a novel leptin-sensitizing drug, which targets ER stress.

  19. Cross-stress resistance in Saccharomyces cerevisiae yeast—new insight into an old phenomenon

    Święciło, Agata

    2016-01-01

    Acquired stress resistance is the result of mild stress causing the acquisition of resistance to severe stress of the same or a different type. The mechanism of “same-stress” resistance (resistance to a second, strong stress after mild primary stress of the same type) probably depends on the activation of defense and repair mechanisms specific for a particular type of stress, while cross-stress resistance (i.e., resistance to a second, strong stress after a different type of mild primary stre...

  20. Valproic Acid Induced Hyperammonaemic Encephalopathy

    Objective: To observe clinical and laboratory features of valproic acid-induced hyperammonaemic encephalopathy in patients taking valproic acid. Methods: Observational study was conducted at the Neurology Department, Dow University of Health Sciences, Civil Hospital, Karachi, from February 26, 2010 to March 20, 2011. Ten patients on valproic acid therapy of any age group with idiopathic or secondary epilepsy, who presented with encephalopathic symptoms, were registered and followed up during the study. Serum ammonia level, serum valproic acid level, liver function test, cerebrospinal fluid examination, electroencephalogram and brain imaging of all the patients were done. Other causes of encephalopathy were excluded after clinical and appropriate laboratory investigations. Microsoft Excel 2007 was used for statistical analysis. Results: Hyperammonaemia was found in all patients with encephalopathic symptoms. Rise in serum ammonia was independent of dose and serum level of valproic acid. Liver function was also found to be normal in 80% (n=8) of the patients. Valproic acid was withdrawn in all patients. Three (30%) patients improved only after the withdrawal of valproic acid. Six (60%) patients improved after L-Carnitine replacement, one (10%) after sodium benzoate. On followup, serum ammonia had reduced to normal in five (50%) patients and to more than half of the baseline level in two (20%) patients. Three (30%) patients were lost to followup after complete clinical improvement. Conclusion: Within therapeutic dose and serum levels, valproic acid can cause symptomatic hyperammonaemia resulting in encephalopathy. All patients taking valproic acid presenting with encephalopathic symptoms must be monitored for the condition. (author)

  1. Arabidopsis PED2 positively modulates plant drought stress resistance

    Haitao Shi; Tiantian Ye; Fan Yang; Zhulong Chan

    2015-01-01

    Abscisic acid (ABA) is an important phytohormone that functions in seed germination, plant development, and multiple stress responses. Arabidopsis Peroxisome defective 2 (AtPED2) (also known as AtPEXOXIN14, AtPEX14), is involved in the intracellular transport of thiolase from the cytosol to glyoxysomes, and perosisomal matrix protein import in plants. In this study, we assigned a new role for AtPED2 in drought stress resistance. The transcript level of AtPED2 was down-regulated by ABA and abiotic stress treatments. AtPED2 knockout mutants were insensitive to ABA-mediated seed germination, primary root elongation, and stomatal response, while AtPED2 over-expressing plants were sensitive to ABA in comparison to wide type (WT). AtPED2 also positively regulated drought stress resistance, as evidenced by the changes of water loss rate, electrolyte leakage, and survival rate. Notably, AtPED2 positively modulated expression of several stress-responsive genes (RAB18, RD22, RD29A, and RD29B), positively affected underlying antioxidant enzyme activities and negatively regulated reactive oxygen species (ROS) level under drought stress conditions. Moreover, multiple carbon metabolites including amino acids, organic acids, sugars, sugar alcohols, and aromatic amines were also positively regulated by AtPED2. Taken together, these results indicated a positive role for AtPED2 in drought resistance, through modulation of stress-responsive genes expression, ROS metabolism, and metabolic homeostasis, at least partially.

  2. Alloy SCR-3 resistant to stress corrosion cracking

    Austenitic stainless steel is used widely because the corrosion resistance, workability and weldability are excellent, but the main fault is the occurrence of stress corrosion cracking in the environment containing chlorides. Inconel 600, most resistant to stress corrosion cracking, is not necessarily safe under some severe condition. In the heat-affected zone of SUS 304 tubes for BWRs, the cases of stress corrosion cracking have occurred. The conventional testing method of stress corrosion cracking using boiling magnesium chloride solution has been problematical because it is widely different from actual environment. The effects of alloying elements on stress corrosion cracking are remarkably different according to the environment. These effects were investigated systematically in high temperature, high pressure water, and as the result, Alloy SCR-3 with excellent stress corrosion cracking resistance was found. The physical constants and the mechanical properties of the SCR-3 are shown. The states of stress corrosion cracking in high temperature, high pressure water containing chlorides and pure water, polythionic acid, sodium phosphate solution and caustic soda of the SCR-3, SUS 304, Inconel 600 and Incoloy 800 are compared and reported. (Kako, I.)

  3. Training of resistance to adverse effects of stress

    Problems of general health care are discussed with respect to the resistance of nuclear power plant personnel to the adverse effects of stress. The results of investigation of the mental condition of new participants in the training course at the training and education centre of the Research Institute of Nuclear Power Plants in Trnava, Czechoslovakia, are summarized. They indicate that in addition to professional qualification, the training and education should also concern the way of living of the nuclear power plant personnel. Training of resistance to the adverse efects of stress has been experimentally included in the course. (Z.M.)

  4. Resistance of functional Lactobacillus plantarum strains against food stress conditions.

    Ferrando, Verónica; Quiberoni, Andrea; Reinhemer, Jorge; Suárez, Viviana

    2015-06-01

    The survival of three Lactobacillus plantarum strains (Lp 790, Lp 813 and Lp 998) with functional properties was studied taking into account their resistance to thermal, osmotic and oxidative stress factors. Stress treatments applied were: 52 °C-15 min (Phosphate Buffer pH 7, thermal shock), H2O2 0.1% (p/v) - 30 min (oxidative shock) and NaCl aqueous solution at 17, 25 and 30% (p/v) (room temperature - 1 h, osmotic shock). The osmotic stress was also evaluated on cell growth in MRS broth added of 2, 4, 6, 8 and 10% (p/v) of NaCl, during 20 h at 30 °C. The cell thermal adaptation was performed in MRS broth, selecting 45 °C for 30 min as final conditions for all strains. Two strains (Lp 813 and Lp 998) showed, in general, similar behaviour against the three stress factors, being clearly more resistant than Lp 790. An evident difference in growth kinetics in presence of NaCl was observed between Lp 998 and Lp 813, Lp998 showing a higher optical density (OD570nm) than Lp 813 at the end of the assay. Selected thermal adaptation improved by 2 log orders the thermal resistance of both strains, but cell growth in presence of NaCl was enhanced only in Lp 813. Oxidative resistance was not affected with this thermal pre-treatment. These results demonstrate the relevance of cell technological resistance when selecting presumptive "probiotic" cultures, since different stress factors might considerably affect viability or/and performance of the strains. The incidence of stress conditions on functional properties of the strains used in this work are currently under research in our group. PMID:25790993

  5. Neurobiological mechanisms supporting experience-dependent resistance to social stress.

    Cooper, M A; Clinard, C T; Morrison, K E

    2015-04-16

    Humans and other animals show a remarkable capacity for resilience following traumatic, stressful events. Resilience is thought to be an active process related to coping with stress, although the cellular and molecular mechanisms that support active coping and stress resistance remain poorly understood. In this review, we focus on the neurobiological mechanisms by which environmental and social experiences promote stress resistance. In male Syrian hamsters, exposure to a brief social defeat stressor leads to increased avoidance of novel opponents, which we call conditioned defeat. Also, hamsters that have achieved dominant social status show reduced conditioned defeat as well as cellular and molecular changes in the neural circuits controlling the conditioned defeat response. We propose that experience-dependent neural plasticity occurs in the prelimbic (PL) cortex, infralimbic (IL) cortex, and ventral medial amygdala (vMeA) during the maintenance of dominance relationships, and that adaptations in these neural circuits support stress resistance in dominant individuals. Overall, behavioral treatments that promote success in competitive interactions may represent valuable interventions for instilling resilience. PMID:25677096

  6. Reduced resistance to oxidative stress during reproduction as a cost of early-life stress.

    Zimmer, Cédric; Spencer, Karen A

    2015-05-01

    Stress exposure during early-life development can have long-term consequences for a variety of biological functions including oxidative stress. The link between early-life stress and oxidative balance is beginning to be explored and previous studies have focused on this link in adult non-breeding or immature individuals. However, as oxidative stress is considered as the main physiological mechanism underlying the trade-off between self-maintenance and investment in reproduction, it is necessary to look at the consequences of early-life stress on oxidative status during reproduction. Here, we investigated the effects of exposure to pre- and/or post-natal stress on oxidative balance during reproduction under benign or stressful environmental conditions in an avian model species, the Japanese quail. We determined total antioxidant status (TAS), total oxidant status (TOS) and resistance to a free-radical attack in individual exposed to pre-natal stress, post-natal stress or both and in control individuals exposed to none of the stressors. TAS levels decreased over time in all females that reproduced under stressful conditions. TOS decreased between the beginning and the end of reproductive period in pre-natal control females. In all females, resistance to a free-radical attack decreased over the reproductive event but this decrease was more pronounced in females from a pre-natal stress development. Our results suggest that pre-natal stress may be associated with a higher cost of reproduction in terms of oxidative stress. These results also confirm that early-life stress can be associated with both benefits and costs depending of the life-history stage or environmental context. PMID:25542633

  7. Study of resistance change and open failure at stripe and viahole by stress-migration

    Wada, T.; Hata, Y.

    1992-08-01

    Through investigation of stress-migration, the following have been found. 1. The resistance of a stripe decreases by mechanical stress and/or temperature below the temperature of annealing. The ratio of decrease of resistance will be the important factor for the study of stress-migration. 2. These sample structure with long lifetime on electromigration, does not always have long lifetime on stress-migration. 3. Al-Si-Cu has a strong stress-migration resistance. For relaxation of stress, Cu segregates at the aluminum grain boundary and the resistance decreases. 4. Stress induced open failure occurred at viaholes. This failure depends on the size of the viahole.

  8. Production of dormant stages and stress resistance of polar cyanobacteria

    Tashyreva, D.; Elster, Josef

    Dordrecht : Springer Science + Business Media, 2012 - (Hanslmeier, A.; Kempe, S.; Seckbach, J.), 367-386 ISBN 978-94-007-4965-8. - (Cellular Origin , Life in Extreme Habitats and Astrobiology. 24) R&D Projects: GA MŠk ME 934; GA MŠk LA341 Institutional research plan: CEZ:AV0Z60050516 Keywords : Cyanobacteria * dormant stages * stress resistance Subject RIV: EH - Ecology, Behaviour

  9. Resistance to biotic and abiotic stresses in avena

    Sánchez Martín, Javier

    2012-01-01

    Oat is an important grain and forage crop cultivated over than 9 million hectares globally. However, drought and biotrophic fungal diseases, such as crown rust (Puccinia coronata f. sp. avenae) and powdery mildew (Blumeria graminis f. sp. avenae) seriously threaten oat production. To combat this, agricultural scientists must develop a comprehensive understanding of the mechanisms through which plants can tolerate/resist stress and translate this to crop breeding programmes. Thu...

  10. Experimental evidence for nutrition regulated stress resistance in Drosophila ananassae.

    Seema Sisodia

    Full Text Available BACKGROUND: The amount and quality of nutrients consumed by organisms have a strong impact on stress resistance, life-history traits and reproduction. The balance between energy acquisition and expenditure is crucial to the survival and reproductive success of animals. The ability of organisms to adjust their development, physiology or behavior in response to environmental conditions, called phenotypic plasticity, is a defining property of life. One of the most familiar and important examples of phenotypic plasticity is the response of stress tolerance and reproduction to changes in developmental nutrition. Larval nutrition may affect a range of different life-history traits as well as responses to environmental stress in adult. PRINCIPAL FINDINGS: Here we investigate the effect of larval nutrition on desiccation, starvation, chill-coma recovery, heat resistance as well as egg to adult viability, egg production and ovariole number in Drosophila ananassae. We raised larvae on either protein rich diet or carbohydrate rich diet. We found that flies consuming protein rich diet have higher desiccation and heat shock resistance whereas flies developed on carbohydrate rich diet have higher starvation and cold resistance. Egg production was higher in females developed on protein rich diet and we also found trade-off between egg production and Egg to adult viability of the flies. Viability was higher in carbohydrate rich diet. However, sex specific viability was found in different nutritional regimes. Higher Egg production might be due to higher ovariole number in females of protein rich diet. CONCLUSION: Thus, Drosophila ananassae adapts different stress tolerance and life-history strategies according to the quality of the available diet, which are correlated with phenotypic adjustment at anatomical and physiological levels.

  11. Longevity in mice: is stress resistance a common factor?

    Brown-Borg, H.M.

    2006-01-01

    A positive relationship between stress resistance and longevity has been reported in a multitude of studies in organisms ranging from yeast to mice. Several mouse lines have been discovered or developed that exhibit extended longevities when compared with normal, wild-type mice of the same genetic background. These long-living lines include the Ames dwarf, Snell dwarf, growth hormone receptor knockout (Laron dwarf), IGF-1 receptor heterozygote, Little, α-MUPA knockout, p66shc knockout, FIRKO,...

  12. Trehalose metabolism and stress resistance in Aspergillus niger

    Svanström, Åsa

    2013-01-01

    Food spoilage by filamentous fungi, moulds, is a global issue of great significance. Mould growth can cause food losses due to deterioration, and adverse health effects due to toxin production. Conidia, asexual spores, are the main factors of dispersal and infection in most food-relevant moulds. They therefore constitute important objects of study when trying to improve food safety. This thesis sought to increase understanding of conidial germination and stress resistance in the common foo...

  13. Effect of cold working and applied stress on the stress corrosion cracking resistance of nickel-chromium-iron alloys

    In order to grasp the stress corrosion cracking quantitative resistance of Alloys 600 and 690 in PWR primary water, the authors have studied the effect of cold working and applied stress on the stress corrosion cracking resistance of Alloys 600 and 690, in high temperature water. Stress corrosion cracking tests were conducted at 360 degrees C (633K) in a simulated PWR primary water for about 12,000 hours or 24,000 hours. From the test results, it is concluded that the stress corrosion cracking resistance in the cold worked Alloy 600 at the same applied stress level increases with an increase in cold working ratio, and the cold worked Alloys of thermally treated 690 have the excellent stress corrosion cracking resistance. Further, in this paper, the planning of stress corrosion cracking test for weld joints and weld metal of Alloy 600 is described

  14. Multi-stress resistance in Lactococcus lactis is actually escape from purine-induced stress sensitivity

    Ryssel, Mia; Hviid, Anne-Mette Meisner; Dawish, Mohamed S.;

    2014-01-01

    to the acid-stress medium increased the stress sensitivity of L. lactis MG1363. It is also shown that high intracellular guanine nucleotide pools confer increased sensitivity to high temperatures, thus showing that it is indeed a multi-stress phenotype. Our analysis suggests that an increased level......Multi-stress resistance is a widely documented and fascinating phenotype of lactococci where single mutations, preferentially in genes involved in nucleotide metabolism and phosphate uptake, result in elevated tolerance to multiple stresses simultaneously. In this report, we have analysed the...... metabolic basis behind this multi-stress-resistance phenotype in Lactococcus lactis subsp. cremoris MG1363 using acid stress as a model of multi-stress resistance. Surprisingly, we found that L. lactis MG1363 is fully resistant to pH 3.0 in the chemically defined SA medium, contrary to its sensitivity in...

  15. Resistance and resilience: the final frontier in traumatic stress management.

    Everly, George S; Welzant, Victor; Jacobson, Jodi M

    2008-01-01

    This paper asserts that the constructs of resistance and resilience represent a domain rich in potential for a wide variety of applications in the field of traumatic stress. Resilience holds great potential for those working in applied settings such as public health planning and preparedness, Employee Assistance Programs (EAPs) and business continuity, as well as transportation, law enforcement, fire suppression, emergency medical services, pre-deployment training for military and other high risk professional groups. Additionally, its application to "the war on terrorism" cannot be denied. Finally, the construct of resilience may have direct applicability to businesses and organizations wherein there is perceived value in preparing a workforce to effectively function under adverse or high stress conditions. The putative value of resistance and resiliency in such applied settings resides in their ability to protect against stress-related behavioral morbidity, as well as counterproductive behavioral reactions. Given its importance, the question arises as to whether resilience is an innate trait or an acquired skill. This paper will report on preliminary data suggesting resiliency may be an attribute that can be acquired through participation in a relatively brief training program. PMID:19278142

  16. Oxidative stress, insulin resistance, dyslipidemia and type 2diabetes mellitus

    Surapon Tangvarasittichai

    2015-01-01

    Oxidative stress is increased in metabolic syndromeand type 2 diabetes mellitus (T2DM) and this appearsto underlie the development of cardiovascular disease,T2DM and diabetic complications. Increased oxidativestress appears to be a deleterious factor leading to insulin resistance, dyslipidemia, β-cell dysfunction, impaired glucose tolerance and ultimately leading to T2DM. Chronic oxidative stress, hyperglycemia and dyslipidemia are particularly dangerous for β-cells from lowest levels of antioxidant, have high oxidative energy requirements, decrease the gene expression of key β-cell genes and induce cell death. If β-cell functioning is impaired, it results in an under production of insulin, impairs glucose stimulated insulin secretion, fasting hyperglycemia and eventually the development of T2DM.

  17. Insulin resistance as a physiological defense against metabolic stress

    Nolan, Christopher J; Ruderman, Neil B; Kahn, Steven E;

    2015-01-01

    challenging subgroup of patients with T2D who are overweight or obese with insulin resistance (IR) and the most refractory hyperglycemia due to an inability to change lifestyle to reverse positive energy balance. For this subgroup of patients with T2D, we question the dogma that IR is primarily harmful...... with intensive insulin therapy, could therefore be harmful. Treatments that nutrient off-load to lower glucose are more likely to be beneficial. The concepts of "IR as an adaptive defense mechanism" and "insulin-induced metabolic stress" may provide explanation for some of the unexpected outcomes of recent major...

  18. Oxidative Stress: A Potential Recipe For Anxiety, Hypertension and Insulin Resistance

    Salim, Samina; Asghar, Mohammad; Chugh, Gaurav; Taneja, Manish; Xia, Zhilian; Saha, Kaustav

    2010-01-01

    We recently reported involvement of oxidative stress in anxiety-like behavior of rats. Others in separate studies have demonstrated a link between oxidative stress and hypertension as well as with type 2 diabetes/insulin resistance. In the present study, we have tested a putative role of oxidative stress in anxiety-like behavior, hypertension and insulin resistance using a rat model of oxidative stress. Oxidative stress in rats was produced by xanthine (0.1%; drinking water) and xanthine oxid...

  19. Increased isoprostane levels in oleic acid-induced lung injury

    Ono, Koichi [Department of Anesthesiology and Resuscitation, Shinshu University School of Medicine, Matsumoto (Japan); Koizumi, Tomonobu, E-mail: tomonobu@shinshu-u.ac.jp [First Department of Internal Medicine, Shinshu University School of Medicine, Matsumoto (Japan); Tsushima, Kenji; Yoshikawa, Sumiko; Yokoyama, Toshiki [First Department of Internal Medicine, Shinshu University School of Medicine, Matsumoto (Japan); Nakagawa, Rikimaru [Department of Anesthesiology and Resuscitation, Shinshu University School of Medicine, Matsumoto (Japan); Obata, Toru [Department of Molecular Cell Biology, Institute of DNA Medicine, Jikei University School of Medicine, Tokyo (Japan)

    2009-10-16

    The present study was performed to examine a role of oxidative stress in oleic acid-induced lung injury model. Fifteen anesthetized sheep were ventilated and instrumented with a lung lymph fistula and vascular catheters for blood gas analysis and measurement of isoprostanes (8-epi prostaglandin F2{alpha}). Following stable baseline measurements, oleic acid (0.08 ml/kg) was administered and observed 4 h. Isoprostane was measured by gas chromatography mass spectrometry with the isotope dilution method. Isoprostane levels in plasma and lung lymph were significantly increased 2 h after oleic acid administration and then decreased at 4 h. The percent increases in isoprostane levels in plasma and lung lymph at 2 h were significantly correlated with deteriorated oxygenation at the same time point, respectively. These findings suggest that oxidative stress is involved in the pathogenesis of the pulmonary fat embolism-induced acute lung injury model in sheep and that the increase relates with the deteriorated oxygenation.

  20. Role of the Stringent Stress Response in the Antibiotic Resistance Phenotype of Methicillin-Resistant Staphylococcus aureus.

    Aedo, Sandra; Tomasz, Alexander

    2016-04-01

    Resistance to beta-lactam antibiotics in methicillin-resistantStaphylococcus aureus(MRSA) requires the presence of an acquired genetic determinant,mecAormecC, which encode penicillin-binding protein PBP2A or PBP2A', respectively. Although all MRSA strains share a mechanism of resistance, the phenotypic expression of beta-lactam resistance shows considerable strain-to-strain variation. The stringent stress response, a stress response that results from nutrient limitation, was shown to play a key role in determining the resistance level of an MRSA strain. In the present study, we validated the impact of the stringent stress response on transcription and translation ofmecAin the MRSA clinical isolate strain N315, which also carries known regulatory genes (mecI/mecR1/mecR2andblaI/blaR1) formecAtranscription. We showed that the impact of the stringent stress response on the resistance level may be restricted to beta-lactam resistance based on a "foreign" determinant such asmecA, as opposed to resistance based on mutations in the nativeS. aureusdeterminantpbpB(encoding PBP2). Our observations demonstrate that high-level resistance mediated by the stringent stress response follows the current model of beta-lactam resistance in which the native PBP2 protein is also essential for expression of the resistance phenotype. We also show that theStaphylococcus sciuri pbpDgene (also calledmecAI), the putative evolutionary precursor ofmecA, confers oxacillin resistance in anS. aureusstrain, generating a heterogeneous phenotype that can be converted to high and homogenous resistance by induction of the stringent stress response in the bacteria. PMID:26833147

  1. Stressful life events are associated with insulin resistance among Chinese immigrant women in the United States

    Carolyn Y. Fang

    2015-01-01

    Conclusions: This is one of the first studies to examine the associations between psychosocial stress and insulin resistance in Chinese immigrant women. These findings contribute to a growing body of literature on stress and diabetes risk in an immigrant population.

  2. Geographic variation for climatic stress resistance traits in the sprintail Orchesella cincta

    Bahrndorff, Simon; Holmstrup, Martin; Petersen, H.;

    2006-01-01

    Multiple traits of stress resistance were investigated in the epedaphic springtail Orchesella cincta. Second generation adults from five laboratory populations were compared with respect to resistance to extreme temperatures and desiccation, and traits relevant to climatic adaptation. Populations...... in stress resistance of springtails related to climatic conditions. Keywords: Geographic variation; Climatic change; Adaptation; Orchesella cincta; Soil ecosystems......Multiple traits of stress resistance were investigated in the epedaphic springtail Orchesella cincta. Second generation adults from five laboratory populations were compared with respect to resistance to extreme temperatures and desiccation, and traits relevant to climatic adaptation. Populations...

  3. Mitochondria, cellular stress resistance, somatic cell depletion and lifespan.

    Robb, Ellen L; Page, Melissa M; Stuart, Jeffrey A

    2009-03-01

    The causes of aging and determinants of maximum lifespan in animal species are multifaceted and complex. However, a wealth of experimental data suggests that mitochondria are involved both in the aging process and in regulating lifespan. Here we outline a somatic cell depletion (SCD) model to account for correlations between: (1) mitochondrial reactive oxygen species and lifespan; (2) mitochondrial antioxidant enzymes and lifespan; (3) mitochondrial DNA mutation and lifespan and (4) cellular stress resistance and lifespan. We examine the available data from within the framework of the SCD model, in which mitochondrial dysfunction leading to cell death and gradual loss of essential somatic cells eventually contributes to the decline in physiological performance that limits lifespan. This model is useful in explaining many of the mitochondrial manipulations that alter maximum lifespan in a variety of animal species; however, there are a number of caveats and critical experiments outstanding, and these are outlined in this review. PMID:20021396

  4. Role of oxidative stress in endothelial insulin resistance

    Francesco Paneni; Sarah Costantino; Francesco Cosentino

    2015-01-01

    The International Diabetes Federation estimates that 316 million people are currently affected by impaired glucose tolerance (IGT). Most importantly, recent forecasts anticipate a dramatic IGT increase with more that 470 million people affected by the year 2035. Impaired insulin sensitivity is major feature of obesity and diabetes and is strongly linked with adverse cardiometabolic phenotypes. However, the etiologic pathway linking impaired glucose tolerance and cardiovascular disease remains to be deciphered. Although insulin resistance has been attributed to inflammatory programs starting in adipose tissue, emerging evidence indicates thatendothelial dysfunction may represent the upstreamevent preceding peripheral impairment of insulinsensitivity. Indeed, suppression of reactive oxygenspecies-dependent pathways in the endothelium hasshown to restore insulin delivery to peripheral organsby preserving nitric oxide (NO) availability. Here wedescribe emerging theories concerning endothelialinsulin resistance, with particular emphasis on the roleoxidative stress. Complex molecular circuits includingendothelial nitric oxide synthase, prostacyclin synthase,mitochondrial adaptor p66Shc, nicotinamide adeninedinucleotide phosphate-oxidase oxidase and nuclearfactor kappa-B are discussed. Moreover, the reviewprovides insights on the effectiveness of availablecompounds (i.e. , ruboxistaurin, sildenafil, endothelinreceptor antagonists, NO donors) in restoring endothelialinsulin signalling. Taken together, these aspects maysignificantly contribute to design novel therapeuticapproaches to restore glucose homeostasis in patientswith obesity and diabetes.

  5. Valproic acid induced pancreatitis: a case report

    Bhupen Barman

    2014-08-01

    Full Text Available Valproic acid is a commonly used antiepileptic drug. Apart from its common side effect there is definite association between valproic acid therapy and acute pancreatitis. Since 1979, many cases of acute pancreatitis induced by valproic acid have been published in medical literature. Here we are reporting a case of valproic acid induced acute pancreatitis in a 27 years old boy. The treatment is supportive, re-challenge is hazardous and should be avoided. [Int J Res Med Sci 2014; 2(4.000: 1765-1767

  6. Mefenamic Acid Induced Nephrotoxicity: An Animal Model

    Muhammad Nazrul Somchit

    2014-12-01

    Full Text Available Purpose: Nonsteroidal anti-inflammatory drugs (NSAIDs are used for the treatment of many joint disorders, inflammation and to control pain. Numerous reports have indicated that NSAIDs are capable of producing nephrotoxicity in human. Therefore, the objective of this study was to evaluate mefenamic acid, a NSAID nephrotoxicity in an animal model. Methods: Mice were dosed intraperitoneally with mefenamic acid either as a single dose (100 or 200 mg/kg in 10% Dimethyl sulfoxide/Palm oil or as single daily doses for 14 days (50 or 100 mg/kg in 10% Dimethyl sulfoxide/Palm oil per day. Venous blood samples from mice during the dosing period were taken prior to and 14 days post-dosing from cardiac puncture into heparinized vials. Plasma blood urea nitrogen (BUN and creatinine activities were measured. Results: Single dose of mefenamic acid induced mild alteration of kidney histology mainly mild glomerular necrosis and tubular atrophy. Interestingly, chronic doses induced a dose dependent glomerular necrosis, massive degeneration, inflammation and tubular atrophy. Plasma blood urea nitrogen was statistically elevated in mice treated with mefenamic acid for 14 days similar to plasma creatinine. Conclusion: Results from this study suggest that mefenamic acid as with other NSAIDs capable of producing nephrotoxicity. Therefore, the study of the exact mechanism of mefenamic acid induced severe nephrotoxicity can be done in this animal model.

  7. Relationship Between Physiological-biochemical Changes Under Drought Stress and Drought Resistance in Ramie

    JIE Yu-cheng; HUANG Pi-sheng; LI Zong-dao

    2001-01-01

    A study on the physiological-biochemical changes of different ramie(Boehmeria Jacq. ) varieties under drought stress was carried out, the results showed that relative water contents(RWC) decreased and RPP increased with the increase of drought stress. Compared with drought sensitive varieties, drought resistant varieties had higher RWC in leaves but lower RPP. Peroxidase activity of drought-resistance varieties changed from low to high whereas sensitive ones changed in opposite direction. Proline contents of drought sensitive varieties was higher than those of drought resistant ones under a certain degree drought stress. Proline accumulation in drought resistant varieties was faster than that in drought sensitive ones under serious drought stress.MDA contents in leaf was increased under drought stress. MDA contents increased slowly in resistant varieties while that increased rapidly in sensitive ones.

  8. Effect of cold working on the stress corrosion cracking resistance of nickel-chromium-iron alloys

    In order to grasp the stress corrosion cracking resistance of cold worked nickel base alloys in PWR primary water, the effect of cold working on the stress corrosion cracking resistance of alloys 600, X-750 and 690, in high temperature water, have been studied. Stress corrosion cracking tests were conducted at 3600C (633K) in a simulated PWR primary water for about 12,000 hours (43.2Ms). From the test results, it is concluded that the stress corrosion cracking resistance in the cold worked Alloy 600 at the same applied stress level increases with an increase in cold working ratio, and the cold worked alloys of thermally treated 690 and X-750 have excellent stress corrosion cracking resistance. (Author)

  9. Angiotensin II Receptor Blocker Ameliorates Stress-Induced Adipose Tissue Inflammation and Insulin Resistance

    Motoharu Hayashi; Kyosuke Takeshita; Yasuhiro Uchida; Koji Yamamoto; Ryosuke Kikuchi; Takayuki Nakayama; Emiko Nomura; Xian Wu Cheng; Tadashi Matsushita; Shigeo Nakamura; Toyoaki Murohara

    2014-01-01

    A strong causal link exists between psychological stress and insulin resistance as well with hypertension. Meanwhile, stress-related responses play critical roles in glucose metabolism in hypertensive patients. As clinical trials suggest that angiotensin-receptor blocker delays the onset of diabetes in hypertensive patients, we investigated the effects of irbesartan on stress-induced adipose tissue inflammation and insulin resistance. C57BL/6J mice were subjected to 2-week intermittent restra...

  10. Exercise-induced stress resistance is independent of exercise controllability and the medial prefrontal cortex

    Greenwood, Benjamin N.; Spence, Katie G.; Crevling, Danielle M.; Clark, Peter J.; Craig, Wendy C.; Fleshner, Monika

    2012-01-01

    Exercise increases resistance against stress-related disorders such as anxiety and depression. Similarly, the perception of control is a powerful predictor of neurochemical and behavioral responses to stress, but whether the experience of choosing to exercise, and exerting control over that exercise, is a critical factor in producing exercise-induced stress resistance is unknown. The current studies investigated whether the protective effects of exercise against the anxiety- and depression-li...

  11. Salt stress in maize: effects, resistance mechanisms, and management. A review

    Farooq, Muhammad; Hussain, Mubshar; Wakeel, Abdul; Kadambot H M Siddique

    2015-01-01

    Maize is grown under a wide spectrum of soil and climatic conditions. Maize is moderately sensitive to salt stress; therefore, soil salinity is a serious threat to its production worldwide. Understanding maize response to salt stress and resistance mechanisms and overviewing management options may help to devise strategies for improved maize performance in saline environments. Here, we reviewed the effects, resistance mechanisms, and management of salt stress in maize. Our main conclusions ar...

  12. Abiotic stresses affect Trichoderma harzianum T39-induced resistance to downy mildew in grapevine.

    Roatti, Benedetta; Perazzolli, Michele; Gessler, Cesare; Pertot, Ilaria

    2013-12-01

    Enhancement of plant defense through the application of resistance inducers seems a promising alternative to chemical fungicides for controlling crop diseases but the efficacy can be affected by abiotic factors in the field. Plants respond to abiotic stresses with hormonal signals that may interfere with the mechanisms of induced systemic resistance (ISR) to pathogens. In this study, we exposed grapevines to heat, drought, or both to investigate the effects of abiotic stresses on grapevine resistance induced by Trichoderma harzianum T39 (T39) to downy mildew. Whereas the efficacy of T39-induced resistance was not affected by exposure to heat or drought, it was significantly reduced by combined abiotic stresses. Decrease of leaf water potential and upregulation of heat-stress markers confirmed that plants reacted to abiotic stresses. Basal expression of defense-related genes and their upregulation during T39-induced resistance were attenuated by abiotic stresses, in agreement with the reduced efficacy of T39. The evidence reported here suggests that exposure of crops to abiotic stress should be carefully considered to optimize the use of resistance inducers, especially in view of future global climate changes. Expression analysis of ISR marker genes could be helpful to identify when plants are responding to abiotic stresses, in order to optimize treatments with resistance inducers in field. PMID:23841621

  13. Low dose of oleanolic acid protects against lithocholic acid-induced cholestasis in mice: potential involvement of nuclear factor-E2-related factor 2-mediated upregulation of multidrug resistance-associated proteins.

    Chen, Pan; Zeng, Hang; Wang, Yongtao; Fan, Xiaomei; Xu, Chenshu; Deng, Rongrong; Zhou, Xunian; Bi, Huichang; Huang, Min

    2014-05-01

    Oleanolic acid (OA) is a natural triterpenoid and has been demonstrated to protect against varieties of hepatotoxicants. Recently, however, OA at high doses was reported to produce apparent cholestasis in mice. In this study, we characterized the protective effect of OA at low doses against lithocholic acid (LCA)-induced cholestasis in mice and explored further mechanisms. OA cotreatment (5, 10, and 20 mg/kg, i.p.) significantly improved mouse survival rate, attenuated liver necrosis, and decreased serum alanine aminotransferase, aspartate aminotransferase, and alkaline phosphatase; more importantly, serum total bile acids and bilirubin, as well as hepatic total bile acids were also remarkably reduced. Gene and protein expression analysis showed that hepatic expression of multidrug resistance-associated protein 2 (Mrp2), Mrp3, and Mrp4 was significantly increased by OA cotreatment, whereas other bile acid metabolism- and transport-related genes, including Na+/taurocholate cotransporter, organic anion transporter 1b2, bile salt export pump, multidrug resistance protein 3, Cyp3a11, Cyp2b10, Sulfotransferase 2a1 (Sult2a1), and UDP-glucuronosyltransferase 1a1 (Ugt1a1), were only slightly changed. OA also caused increased nuclear factor-E2-related factor (Nrf2) mRNA expression and nuclear protein accumulation, whereas nuclear receptors farnesoid X receptor (FXR), pregnane X receptor (PXR), and constitutive androstane receptor were not significantly influenced by OA. Luciferase (Luc) assays performed in HepG2 cells illustrated that OA was a strong Nrf2 agonist with moderate PXR and weak FXR agonism. Finally, in mouse primary cultured hepatocytes, OA dose- and time-dependently induced expression of Mrp2, Mrp3, and Mrp4; however, this upregulation was abrogated when Nrf2 was silenced. In conclusion, OA produces a protective effect against LCA-induced hepatotoxicity and cholestasis, possibly due to Nrf2-mediated upregulation of Mrp2, Mrp3, and Mrp4. PMID:24510383

  14. Induced resistance in tomato by SAR activators during predisposing salinity stress

    Matthew Francis Pye

    2013-05-01

    Full Text Available Plant activators are chemicals that induce disease resistance. The phytohormone salicylic acid (SA is a crucial signal for systemic acquired resistance (SAR, and SA-mediated resistance is a target of several commercial plant activators, including Actigard (1,2,3-benzothiadiazole-7-thiocarboxylic acid-s-methyl-ester, BTH and Tiadinil (N-(3-chloro-4-methylphenyl-4-methyl-1,2,3-thiadiazole-5-carboxamide, TDL. BTH and TDL were examined for their impact on abscisic acid (ABA-mediated, salt-induced disease predisposition in tomato seedlings. A brief episode of salt stress to roots significantly increased the severity of disease caused by Pseudomonas syringae pv. tomato (Pst and Phytophthora capsici relative to non-stressed plants. Root treatment with TDL induced resistance to Pst in leaves and provided protection in both non-stressed and salt-stressed seedlings in WT and highly susceptible NahG plants. Non-stressed and salt-stressed ABA-deficient sitiens mutants were highly resistant to Pst. Neither TDL nor BTH induced resistance to root infection by P. capsici, nor did they moderate the salt-induced increment in disease severity. Root treatment with these plant activators increased the levels of ABA in roots and shoots similar to levels observed in salt-stressed plants. The results indicate that SAR activators can protect tomato plants from bacterial speck disease under predisposing salt stress, and suggest that some SA-mediated defense responses function sufficiently in plants with elevated levels of ABA.

  15. Transgenic crops with an improved resistance to biotic stresses. A review

    Tohidfar, M.

    2015-01-01

    Full Text Available Introduction. Pests, diseases and weeds (biotic stresses are significant limiting factors for crop yield and production. However, the limitations associated with conventional breeding methods necessitated the development of alternative methods for improving new varieties with higher resistance to biotic stresses. Molecular techniques have developed applicable methods for genetic transformation of a wide range of plants. Genetic engineering approach has been demonstrated to provide enormous options for the selection of the resistance genes from different sources to introduce them into plants to provide resistance against different biotic stresses. Literature. In this review, we focus on strategies to achieve the above mentioned objectives including expression of insecticidal, antifungal, antibacterial, antiviral resistance and herbicide detoxification for herbicide resistance. Conclusion. Regardless of the concerns about commercialization of products from genetically modified (GM crops resistant to biotic stresses, it is observed that the cultivation area of these crops is growing fast each year. Considering this trend, it is expected that production and commercialization of GM crops resistant to biotic stresses will continue to increase but will also extend to production of crops resistant to abiotic stresses (e.g. drought, salinity, etc. in a near future.

  16. Genome-wide association analysis of oxidative stress resistance in Drosophila melanogaster.

    Allison L Weber

    Full Text Available BACKGROUND: Aerobic organisms are susceptible to damage by reactive oxygen species. Oxidative stress resistance is a quantitative trait with population variation attributable to the interplay between genetic and environmental factors. Drosophila melanogaster provides an ideal system to study the genetics of variation for resistance to oxidative stress. METHODS AND FINDINGS: We used 167 wild-derived inbred lines of the Drosophila Genetic Reference Panel for a genome-wide association study of acute oxidative stress resistance to two oxidizing agents, paraquat and menadione sodium bisulfite. We found significant genetic variation for both stressors. Single nucleotide polymorphisms (SNPs associated with variation in oxidative stress resistance were often sex-specific and agent-dependent, with a small subset common for both sexes or treatments. Associated SNPs had moderately large effects, with an inverse relationship between effect size and allele frequency. Linear models with up to 12 SNPs explained 67-79% and 56-66% of the phenotypic variance for resistance to paraquat and menadione sodium bisulfite, respectively. Many genes implicated were novel with no known role in oxidative stress resistance. Bioinformatics analyses revealed a cellular network comprising DNA metabolism and neuronal development, consistent with targets of oxidative stress-inducing agents. We confirmed associations of seven candidate genes associated with natural variation in oxidative stress resistance through mutational analysis. CONCLUSIONS: We identified novel candidate genes associated with variation in resistance to oxidative stress that have context-dependent effects. These results form the basis for future translational studies to identify oxidative stress susceptibility/resistance genes that are evolutionary conserved and might play a role in human disease.

  17. Resistance to oxidative stress shows low heritability and high common environmental variance in a wild bird.

    Losdat, S; Helfenstein, F; Blount, J D; Richner, H

    2014-09-01

    Oxidative stress was recently demonstrated to affect several fitness-related traits and is now well recognized to shape animal life-history evolution. However, very little is known about how much resistance to oxidative stress is determined by genetic and environmental effects and hence about its potential for evolution, especially in wild populations. In addition, our knowledge of phenotypic sexual dimorphism and cross-sex genetic correlations in resistance to oxidative stress remains extremely limited despite important evolutionary implications. In free-living great tits (Parus major), we quantified heritability, common environmental effect, sexual dimorphism and cross-sex genetic correlation in offspring resistance to oxidative stress by performing a split-nest cross-fostering experiment where 155 broods were split, and all siblings (n = 791) translocated and raised in two other nests. Resistance to oxidative stress was measured as both oxidative damage to lipids and erythrocyte resistance to a controlled free-radical attack. Both measurements of oxidative stress showed low additive genetic variances, high common environmental effects and phenotypic sexual dimorphism with males showing a higher resistance to oxidative stress. Cross-sex genetic correlations were not different from unity, and we found no substantial heritability in resistance to oxidative stress at adult age measured on 39 individuals that recruited the subsequent year. Our study shows that individual ability to resist to oxidative stress is primarily influenced by the common environment and has a low heritability with a consequent low potential for evolution, at least at an early stage of life. PMID:25040169

  18. Assessing Treatment-Resistant Posttraumatic Stress Disorder: The Emory Treatment Resistance Interview for PTSD (E-TRIP)

    Dunlop, Boadie W; Kaye, Joanna L.; Cole Youngner; Barbara Rothbaum

    2014-01-01

    Patients with posttraumatic stress disorder (PTSD) who fail to respond to established treatments are at risk for chronic disability and distress. Although treatment-resistant PTSD (TR-PTSD) is a common clinical problem, there is currently no standard method for evaluating previous treatment outcomes. Development of a tool that could quantify the degree of resistance to previously provided treatments would inform research in patients with PTSD. We conducted a systematic review of PTSD treatme...

  19. Minocycline ameliorates prenatal valproic acid induced autistic behaviour, biochemistry and blood brain barrier impairments in rats.

    Kumar, Hariom; Sharma, Bhupesh

    2016-01-01

    Autism is a neurodevelopment disorder. One percent worldwide population suffers with autism and males suffer more than females. Microglia plays an important role in neurodevelopment, neuropsychiatric and neurodegenerative disorders. The present study has been designed to investigate the role of minocycline in prenatal valproic acid induced autism in rats. Animals with prenatal valproic acid have reduced social interaction (three chamber social behaviour apparatus), spontaneous alteration (Y-Maze), exploratory activity (Hole board test), intestinal motility, serotonin levels (both in prefrontal cortex and ileum) and prefrontal cortex mitochondrial complex activity (complexes I, II, IV). Furthermore, prenatal valproic acid treated animals have shown an increase in locomotion (actophotometer), anxiety (elevated plus maze), brain oxidative stress (thiobarbituric acid reactive species, glutathione, catalase), nitrosative stress (nitrite/nitrate), inflammation (both in brain and ileum myeloperoxidase activity), calcium and blood brain barrier permeability. Treatment with minocycline significantly attenuated prenatal valproic acid induced reduction in social interaction, spontaneous alteration, exploratory activity intestinal motility, serotonin levels and prefrontal cortex mitochondrial complex activity. Furthermore, minocycline has also attenuated prenatal valproic acid induced increase in locomotion, anxiety, brain oxidative and nitrosative stress, inflammation, calcium and blood brain barrier permeability. Thus, it may be concluded that prenatal valproic acid has induced autistic behaviour, biochemistry and blood brain barrier impairment in animals, which were significantly attenuated by minocycline. Minocycline should be explored further for its therapeutic benefits in autism. PMID:26551768

  20. [Lipid composition in erythrocytic membranes of rats with various stress resistance during repeated immobilization].

    Tsygvintsev, A A; Bryndina, I G

    2011-01-01

    The dependence between variation of erythrocyte phospholipid composition and stress resistance was studied in chronic experiment on nonline male albino rats, previously differed by their behavior in the 'open field' test. A significant exhausting of membrane pool by the basic classes of phospholipids was registered under influence of 2 hours daily immobilization during 5, 10, 20, 30 days, however, their metabolism for resistant and predisposed to stress animals flows variously. PMID:21688664

  1. Fatty-acid metabolism is involved in stress-resistance mechanisms of Caenorhabditis elegans

    Horikawa, Makoto; Sakamoto, Kazuichi

    2009-01-01

    Fatty acids are the major components of the phospholipid bilayer and are involved in several functions of cell membrane. We previously reported that fatty-acid metabolism is involved in the regulation of DAF-2/insulin signal in Caenorhabditis elegans. In this study, we investigate the role of fatty-acid metabolism in stress resistance with respect to daf-16 in nematode. We found that fatty-acid metabolism regulates heat, osmotic, and oxidative-stress resistance in C. elegans. RNA interference...

  2. Decreased Skin-Mediated Detoxification Contributes to Oxidative Stress and Insulin Resistance

    Xing-Xing Liu; Chang-Bin Sun; Ting-Tong Yang; Da Li; Chun-Yan Li; Yan-Jie Tian; Ming Guo; Yu Cao; Shi-Sheng Zhou

    2012-01-01

    The skin, the body's largest organ, plays an important role in the biotransformation/detoxification and elimination of xenobiotics and endogenous toxic substances, but its role in oxidative stress and insulin resistance is unclear. We investigated the relationship between skin detoxification and oxidative stress/insulin resistance by examining burn-induced changes in nicotinamide degradation. Rats were divided into four groups: sham-operated, sham-nicotinamide, burn, and burn-nicotinamide. Ra...

  3. Heat-resistant protein expression during germination of maize seeds under water stress.

    Abreu, V M; Silva Neta, I C; Von Pinho, E V R; Naves, G M F; Guimarães, R M; Santos, H O; Von Pinho, R G

    2016-01-01

    Low water availability is one of the factors that limit agricultural crop development, and hence the development of genotypes with increased water stress tolerance is a challenge in plant breeding programs. Heat-resistant proteins have been widely studied, and are reported to participate in various developmental processes and to accumulate in response to stress. This study aimed to evaluate heat-resistant protein expression under water stress conditions during the germination of maize seed inbreed lines differing in their water stress tolerance. Maize seed lines 91 and 64 were soaked in 0, -0.3, -0.6, and -0.9 MPa water potential for 0, 6, 12, 18, and 24 h. Line 91 is considered more water stress-tolerant than line 64. The analysis of heat-resistant protein expression was made by gel electrophoresis and spectrophotometry. In general, higher expression of heat-resistant proteins was observed in seeds from line 64 subjected to shorter soaking periods and lower water potentials. However, in the water stress-tolerant line 91, a higher expression was observed in seeds that were subjected to -0.3 and -0.6 MPa water potentials. In the absence of water stress, heat-resistant protein expression was reduced with increasing soaking period. Thus, there was a difference in heat-resistant protein expression among the seed lines differing in water stress tolerance. Increased heat-resistant protein expression was observed in seeds from line 91 when subjected to water stress conditions for longer soaking periods. PMID:27525950

  4. Scale effect in fatigue resistance under complex stressed state

    On the basis the of the fatigue failure statistic theory obtained is the formula for calculated estimation of probabillity of failure under complex stressed state according to partial probabilities of failure under linear stressed state with provision for the scale effect. Also the formula for calculation of equivalent stress is obtained. The verification of both formulae using literary experimental data for plane stressed state torsion has shown that the error of estimations does not exceed 10% for materials with the ultimate strength changing from 61 to 124 kg/mm2

  5. Endoplasmic reticulum stress regulates inflammation and insulin resistance in skeletal muscle from pregnant women.

    Liong, Stella; Lappas, Martha

    2016-04-15

    Sterile inflammation and infection are key mediators of inflammation and peripheral insulin resistance associated with gestational diabetes mellitus (GDM). Studies have shown endoplasmic reticulum (ER) stress to induce inflammation and insulin resistance associated with obesity and type 2 diabetes, however is paucity of studies investigating the effects of ER stress in skeletal muscle on inflammation and insulin resistance associated with GDM. ER stress proteins IRE1α, GRP78 and XBP-1s were upregulated in skeletal muscle of obese pregnant women, whereas IRE1α was increased in GDM women. Suppression of ER stress, using ER stress inhibitor tauroursodeoxycholic acid (TUDCA) or siRNA knockdown of IRE1α and GRP78, significantly downregulated LPS-, poly(I:C)- or IL-1β-induced production of IL-6, IL-8, IL-1β and MCP-1. Furthermore, LPS-, poly(I:C)- or TNF-α-induced insulin resistance was improved following suppression of ER stress, by increasing insulin-stimulated phosphorylation of IR-β, IRS-1, GLUT-4 expression and glucose uptake. In summary, our inducible obesity and GDM-like models suggests that the development of GDM may be involved in activating ER stress-induced inflammation and insulin resistance in human skeletal muscle. PMID:26902174

  6. Severe Injury Is Associated With Insulin Resistance, Endoplasmic Reticulum Stress Response, and Unfolded Protein Response

    Jeschke, Marc G.; Finnerty, Celeste C.; Herndon, David N.; Song, Juquan; Boehning, Darren; Tompkins, Ronald G.; Baker, Henry V.; Gauglitz, Gerd G.

    2012-01-01

    Objective We determined whether postburn hyperglycemia and insulin resistance are associated with endoplasmic reticulum (ER) stress/unfolded protein response (UPR) activation leading to impaired insulin receptor signaling. Background Inflammation and cellular stress, hallmarks of severely burned and critically ill patients, have been causally linked to insulin resistance in type 2 diabetes via induction of ER stress and the UPR. Methods Twenty severely burned pediatric patients were compared with 36 nonburned children. Clinical markers, protein, and GeneChip analysis were used to identify transcriptional changes in ER stress and UPR and insulin resistance–related signaling cascades in peripheral blood leukocytes, fat, and muscle at admission and up to 466 days postburn. Results Burn-induced inflammatory and stress responses are accompanied by profound insulin resistance and hyperglycemia. Genomic and protein analysis revealed that burn injury was associated with alterations in the signaling pathways that affect insulin resistance, ER/sarcoplasmic reticulum stress, inflammation, and cell growth/apoptosis up to 466 days postburn. Conclusion Burn-induced insulin resistance is associated with persistent ER/sarcoplasmic reticulum stress/UPR and subsequent suppressed insulin receptor signaling over a prolonged period of time. PMID:22241293

  7. Quinolinic acid induces oxidative stress in rat brain synaptosomes

    Santamaria, A.; Galván-Arzate, S.; Lisý, Václav; Ali, S. F.; Duhart, H. M.; Osorio-Rico, L.; Rios, C.; Šťastný, František

    2001-01-01

    Roč. 12, č. 4 (2001), s. 871-874. ISSN 0959-4965 R&D Projects: GA ČR GA309/99/0211; GA ČR GA305/99/1317 Grant ostatní: CONACyT(MX) J28612-M; CONACyT(MX) 130.205 Institutional research plan: CEZ:AV0Z5011922 Keywords : 2-amino-5- phosphonovaleric acid * brain regions * glutathione Subject RIV: FH - Neurology Impact factor: 2.374, year: 2001

  8. Fracture micromechanisms and residual stresses of a highly resistant duplex stainless steel

    Valiente Cancho, Andrés; Mihaela IORDACHESCU; Ruiz Hervías, Jesús; Abreu Rodrigues, Maricely de

    2013-01-01

    The paper presents some preliminary results of an ongoing research intended to qualify a highly resistant duplex stainless steel wire as prestressing steel and, gets on insight on (he wires' fracture micromechanism and residual stresses field. SEM fractographic analysis of the stainless steel wires indicates an anisotropic fracture behavior in tension, in presence of surface flaws, attributed to the residual stresses generated through the fabrication process. The residual stresses magnitude i...

  9. Induction of Drought Stress Resistance by Multi-Functional PGPR Bacillus licheniformis K11 in Pepper

    Lim, Jong-Hui; Kim, Sang-Dal

    2013-01-01

    Drought stress is one of the major yield affecting factor for pepper plant. The effects of PGPRs were analyzed in relation with drought resistance. The PGPRs inoculated pepper plants tolerate the drought stress and survived as compared to non-inoculated pepper plants that died after 15 days of drought stress. Variations in protein and RNA accumulation patterns of inoculated and non-inoculated pepper plants subjected to drought conditions for 10 days were confirmed by two dimensional polyacryl...

  10. Effects of astaxanthin and emodin on the growth, stress resistance and disease resistance of yellow catfish (Pelteobagrus fulvidraco).

    Liu, Fei; Shi, Hong-Zhuan; Guo, Qiao-Sheng; Yu, Ye-Bing; Wang, Ai-Ming; Lv, Fu; Shen, Wen-Biao

    2016-04-01

    Yellow catfish (Pelteobagrus fulvidraco) has become a commercially important fish species in China and eastern Asia. High-density aquaculture has led to congestion and excessive stress and contributed to bacterial infection outbreaks that have caused high mortality. We investigated the effects of dietary supplementation with astaxanthin and emodin alone and in combination on the growth and stress resistance of yellow catfish. After 60 days of feeding, each group of fish (control, astaxanthin, emodin, and astaxanthin plus emodin (combination) groups) was exposed to acute crowding stress for 24 h, and a subsample of fish from the four groups was challenged with the bacterial septicemia pathogen Proteus mirabilis after the end of the crowding stress experiment. Compared with the control, the astaxanthin and emodin groups showed increases in serum total protein (TP), hepatic superoxide dismutase (SOD) activity and hepatic heat shock proteins 70 (HSP70) mRNA levels at 12 and 24 h after the initiation of crowding stress. The combination group exhibited increases in alanine aminotransferase (ALT) activity, aspartate aminotransferase (AST) activity, serum TP, hepatic SOD activity and hepatic HSP70 mRNA levels within 24 h after the initiation of crowding stress. However, decreases relative to the control were observed in the serum cortisol and glucose contents in the three treatment groups at 12 and 24 h after the initiation of crowding stress, in ALT and AST activity in the astaxanthin and emodin group at 24 h after the initiation of crowding stress, and in the serum lysozyme activity, serum alkaline phosphatase (ALP) activity, and hepatic catalase (CAT) and malondialdehyde (MDA) activity in the combination group at 24 h after the initiation of crowding stress. Additionally, the cumulative mortality after P. mirabilis infection was lower in all three treatment groups (57.00%-70.33%) than in the control (77.67%). Dietary supplementation with astaxanthin and emodin

  11. Increased resistance to a generalist herbivore in a salinity-stressed non-halophytic plant.

    Renault, Sylvie; Wolfe, Scott; Markham, John; Avila-Sakar, Germán

    2016-01-01

    Plants often grow under the combined stress of several factors. Salinity and herbivory, separately, can severely hinder plant growth and reproduction, but the combined effects of both factors are still not clearly understood. Salinity is known to reduce plant tissue nitrogen content and growth rates. Since herbivores prefer tissues with high N content, and biochemical pathways leading to resistance are commonly elicited by salt-stress, we hypothesized that plants growing in saline conditions would have enhanced resistance against herbivores. The non-halophyte, Brassica juncea, and the generalist herbivore Trichoplusia ni were used to test the prediction that plants subjected to salinity stress would be both more resistant and more tolerant to herbivory than those growing without salt stress. Plants were grown under different NaCl levels, and either exposed to herbivores and followed by removal of half of their leaves, or left intact. Plants were left to grow and reproduce until senescence. Tissue quality was assessed, seeds were counted and biomass of different organs measured. Plants exposed to salinity grew less, had reduced tissue nitrogen, protein and chlorophyll content, although proline levels increased. Specific leaf area, leaf water content, transpiration and root:shoot ratio remained unaffected. Plants growing under saline condition had greater constitutive resistance than unstressed plants. However, induced resistance and tolerance were not affected by salinity. These results support the hypothesis that plants growing under salt-stress are better defended against herbivores, although in B. juncea this may be mostly through resistance, and less through tolerance. PMID:27169610

  12. THE STRESS RESISTANCE OF STUDENTS. THE PARADIGM OF SUBJECT PERSONALITY SELF- ORGANIZATION

    Sergey I. Dyakov

    2016-01-01

    Full Text Available The aim of the investigation is to consider a problem of stress resistance of students in the context of subject self-organization of the personality. Methods. The following methods of research are used: questioning; psychological and diagnostic tests «Tolerance of Uncertainty» (NTN and «Personal Factors of Decisions» (PFD by T. V. Kornilova; original experimental experiences – «Coding», a technique of a self-assessment (scaling and «A locus control». While data processing the methods of mathematical statistics (SPSS 12 package – the correlation analysis of Pearson and the factorial analysis with rotation use a component by «verimax» method are applied. Results and scientific novelty. Types of subjectivity and strategy of stress resistance are allocated. The nature and a role of the emotional and stressful mechanism having information and semantic properties in its basis are disclosed. Communication of irresponsible mechanisms of mentality with the sphere of consciousness in the context of subjectivity of the personality is shown. Mechanisms of emotional and rational self-control of system of mental self-organization of the person are presented. The statistical and qualitative data opening communications between properties of subjectivity and stress resistance of the personality are empirically obtained. Variation of the relations and also types of subjectivity and stress resistance emphasized based on the results of the presented research. Original (author’s methods of studying of subjectivity and factors of stress resistance are presented. Practical significance. The revealed factors of subject self-organization reveal the stress-producing directions of the environment and the relation of the personality to situations of changes and uncertainty: and also indicate subject properties of resistance to stress which need to be developed to increase the level of health of students, to reduce risk of deviance and delinquency of

  13. Influence of stress on creep deformation properties of 9-12Cr ferritic creep resistant steels

    Kimura, K.; Sawada, K.; Kushima, H. [National Institute for Materials Science (Japan)

    2008-07-01

    Creep deformation property of 9-12Cr ferritic creep resistant steels was investigated. With decrease in stress, a magnitude of creep strain at the onset of accelerating creep stage decreased from about 2% in the short-term to less than 1% in the longterm. A time to 1% total strain was observed in the transient creep stage in the short term regime, however, it shifted to the accelerating creep stage in the long-term regime. Life fraction of the times to 1% creep strain and 1% total strain tended to increase with decrease in stress. Difference in stress dependence of the minimum creep rate was observed in the high- and low-stress regimes with a boundary condition of 50% of 0.2% offset yield stress. Stress dependence of the minimum creep rate in the high stress regime was equivalent to a strain rate dependence of the flow stress evaluated by tensile test, and a magnitude of stress exponent, n, in the high stress regime decreased with increase in temperature from 20 at 550 C to 10 at 700 C. On the other hand, n value in the low stress regime was about 5, and creep deformation in the low stress regime was considered to be controlled by dislocation climb. Creep rupture life was accurately predicted by a region splitting method by considering a change in stress dependence of creep deformation. (orig.)

  14. Reduced resistance to oxidative stress during reproduction as a cost of early-life stress

    Zimmer, C; Spencer, K A

    2015-01-01

    This study was funded by a BBSRC David Phillips Research Fellowship to K.A. Spencer. Stress exposure during early-life development can have long-term consequences for a variety of biological functions including oxidative stress. The link between early-life stress and oxidative balance is beginning to be explored and previous studies have focused on this link in adult non-breeding or immature individuals. However, as oxidative stress is considered as the main physiological mechanism underly...

  15. Possible Pharmacological Approach Targeting Endoplasmic Reticulum Stress to Ameliorate Leptin Resistance in Obesity

    Hosoi, Toru; Ozawa, Koichiro

    2016-01-01

    Obesity is associated with metabolic syndrome, such as diabetes, hypertension, and hyperlipidemia. Therefore, drug development for the treatment of obesity is needed. Leptin is an anti-obesity hormone that inhibits food intake and increases energy metabolism, and, as such, treatments involving leptin were expected to be beneficial for obesity; however, since most obese patients are in a state of leptin resistance, these treatments may not be useful. Therefore, the amelioration of leptin resistance has recently been attracting interest as a treatment for obesity. The mechanisms underlying the development of leptin resistance need to be elucidated in more detail. Endoplasmic reticulum (ER) stress was recently suggested to be involved in the pathogenesis of leptin resistance. The molecular mechanisms responsible for leptin resistance and possible pharmacological treatments for obesity have been discussed herein, with a focus on ER stress.

  16. Developmental Variability of Photooxidative Stress Tolerance in Paraquat-Resistant Conyza.

    Amsellem, Z.; Jansen, MAK.; Driesenaar, ARJ.; Gressel, J.

    1993-12-01

    Paraquat-resistant hairy fleabane (Conyza bonariensis L. Cronq.) has been extensively studied, with some contention. A single, dominant gene pleiotropically controls levels of oxidant-detoxifying enzymes and tolerance to many photooxidants, to photoinhibition, and possibly to other stresses. The weed forms a rosette on humid short days and flowers in dry long days and, thus, needs plasticity to photooxidant stresses. In a series of four experiments over 20 months, the resistant and susceptible biotypes were cultured in constant 10-h low-light short days at 25[deg]C. Resistance was measured as recovery from paraquat. The concentration required to achieve 50% inhibition of the resistant biotype was about 30 times that of the susceptible one just after germination, increased to >300 times that of the susceptibles at 10 weeks of growth, and then decreased to 20-fold, remaining constant except for a brief increase while bolting. Resistance increased when plants were induced to flower by long days. The levels of plastid superoxide dismutase and of glutathione reductase were generally highest in resistant plants compared to those of the susceptibles at the times of highest paraquat resistance, but they were imperceptibly different from the susceptible type at the times of lower paraquat resistance. Photoinhibition tolerance measured as quantum yield of oxygen evolution at ambient temperatures was highest when the relative amounts of enzymes were highest in the resistant biotype. Resistance to photoinhibition was not detected by chlorophyll a fluorescence. Enzyme levels, photoinhibition tolerance, and paraquat resistance all increased during flowering in both biotypes. Imperceptibly small increases in enzyme levels would be needed for 20-fold resistance, based on the moderate enzyme increases correlated with 300-fold resistance. Thus, it is feasible that either these enzymes play a role in the first line of defense against photooxidants, or another, yet unknown mechanism

  17. Alterations in neuronal morphology in infralimbic cortex predict resistance to fear extinction following acute stress.

    Moench, Kelly M; Maroun, Mouna; Kavushansky, Alexandra; Wellman, Cara

    2016-06-01

    Dysfunction in corticolimbic circuits that mediate the extinction of learned fear responses is thought to underlie the perseveration of fear in stress-related psychopathologies, including post-traumatic stress disorder. Chronic stress produces dendritic hypertrophy in basolateral amygdala (BLA) and dendritic hypotrophy in medial prefrontal cortex, whereas acute stress leads to hypotrophy in both BLA and prelimbic cortex. Additionally, both chronic and acute stress impair extinction retrieval. Here, we examined the effects of a single elevated platform stress on extinction learning and dendritic morphology in infralimbic cortex, a region considered to be critical for extinction. Acute stress produced resistance to extinction, as well as dendritic retraction in infralimbic cortex. Spine density on apical and basilar terminal branches was unaffected by stress. However, animals that underwent conditioning and extinction had decreased spine density on apical terminal branches. Thus, whereas dendritic morphology in infralimbic cortex appears to be particularly sensitive to stress, changes in spines may more sensitively reflect learning. Further, in stressed rats that underwent conditioning and extinction, the level of extinction learning was correlated with spine densities, in that rats with poorer extinction retrieval had more immature spines and fewer thin spines than rats with better extinction retrieval, suggesting that stress may have impaired learning-related spine plasticity. These results may have implications for understanding the role of medial prefrontal cortex in learning deficits associated with stress-related pathologies. PMID:26844245

  18. Microarray analyses reveal novel targets of exercise-induced stress resistance in the dorsal raphe nucleus

    Alice B. Loughridge

    2013-05-01

    Full Text Available Serotonin (5-HT is implicated in the development of stress-related mood disorders in humans. Physical activity reduces the risk of developing stress-related mood disorders, such as depression and anxiety. In rats, 6 weeks of wheel running protects against stress-induced behaviors thought to resemble symptoms of human anxiety and depression. The mechanisms by which exercise confers protection against stress-induced behaviors, however, remain unknown. One way by which exercise could generate stress resistance is by producing plastic changes in gene expression in the dorsal raphe nucleus (DRN. The DRN has a high concentration of 5-HT neurons and is implicated in stress-related mood disorders. The goal of the current experiment was to identify changes in the expression of genes that could be novel targets of exercise-induced stress resistance in the DRN. Adult, male F344 rats were allowed voluntary access to running wheels for 6 weeks; exposed to inescapable stress or no stress; and sacrificed immediately and 2 hours after stressor termination. Laser capture microdissection selectively sampled the DRN. mRNA expression was measured using the whole genome Affymetrix microarray. Comprehensive data analyses of gene expression included differential gene expression, log fold change (LFC contrast analyses with False Discovery Rate correction, KEGG and Wiki Web Gestalt pathway enrichment analyses, and Weighted Gene Correlational Network Analysis (WGCNA. Our results suggest that physically active rats exposed to stress modulate expression of twice the number of genes, and display a more rapid and strongly coordinated response, than sedentary rats. Bioinformatics analyses revealed several potential targets of stress resistance including genes that are related to immune processes, tryptophan metabolism, and circadian/diurnal rhythms.

  19. Stress-induced enhancement of fear conditioning and sensitization facilitates extinction-resistant and habituation-resistant fear behaviors in a novel animal model of posttraumatic stress disorder.

    Corley, Michael J; Caruso, Michael J; Takahashi, Lorey K

    2012-01-18

    Posttraumatic stress disorder (PTSD) is characterized by stress-induced symptoms including exaggerated fear memories, hypervigilance and hyperarousal. However, we are unaware of an animal model that investigates these hallmarks of PTSD especially in relation to fear extinction and habituation. Therefore, to develop a valid animal model of PTSD, we exposed rats to different intensities of footshock stress to determine their effects on either auditory predator odor fear extinction or habituation of fear sensitization. In Experiment 1, rats were exposed to acute footshock stress (no shock control, 0.4 mA, or 0.8 mA) immediately prior to auditory fear conditioning training involving the pairing of auditory clicks with a cloth containing cat odor. When presented to the conditioned auditory clicks in the next 5 days of extinction testing conducted in a runway apparatus with a hide box, rats in the two shock groups engaged in higher levels of freezing and head out vigilance-like behavior from the hide box than the no shock control group. This increase in fear behavior during extinction testing was likely due to auditory activation of the conditioned fear state because Experiment 2 demonstrated that conditioned fear behavior was not broadly increased in the absence of the conditioned auditory stimulus. Experiment 3 was then conducted to determine whether acute exposure to stress induces a habituation resistant sensitized fear state. We found that rats exposed to 0.8 mA footshock stress and subsequently tested for 5 days in the runway hide box apparatus with presentations of nonassociative auditory clicks exhibited high initial levels of freezing, followed by head out behavior and culminating in the occurrence of locomotor hyperactivity. In addition, Experiment 4 indicated that without delivery of nonassociative auditory clicks, 0.8 mA footshock stressed rats did not exhibit robust increases in sensitized freezing and locomotor hyperactivity, albeit head out vigilance

  20. Decrypting the H-NS-dependent regulatory cascade of acid stress resistance in Escherichia coli

    Soutourina Olga

    2010-10-01

    Full Text Available Abstract Background H-NS regulates the acid stress resistance. The present study aimed to characterize the H-NS-dependent cascade governing the acid stress resistance pathways and to define the interplay between the different regulators. Results We combined mutational, phenotypic and gene expression analyses, to unravel the regulatory hierarchy in acid resistance involving H-NS, RcsB-P/GadE complex, HdfR, CadC, AdiY regulators, and DNA-binding assays to separate direct effects from indirect ones. RcsB-P/GadE regulatory complex, the general direct regulator of glutamate-, arginine- and lysine-dependent acid resistance pathways plays a central role in the regulatory cascade. However, H-NS also directly controls specific regulators of these pathways (e.g. cadC and genes involved in general stress resistance (hdeAB, hdeD, dps, adiY. Finally, we found that in addition to H-NS and RcsB, a third regulator, HdfR, inversely controls glutamate-dependent acid resistance pathway and motility. Conclusions H-NS lies near the top of the hierarchy orchestrating acid response centred on RcsB-P/GadE regulatory complex, the general direct regulator of glutamate-, arginine- and lysine-dependent acid resistance pathways.

  1. Asg1 is a stress-inducible gene which increases stomatal resistance in salt stressed potato

    Batelli, Giorgia; Massarelli, Immacolata; Van Oosten, Michael; Nurcato, Roberta; Vannini, Candida; Raimondi, Giampaolo; Leone, Antonella; Zhu, Jian-Kang; Maggio, Albino; Grillo, Stefania

    2012-01-01

    The identification of critical components in plant salt stress adaptation has greatly benefitted, in the last two decades, from fundamental discoveries in Arabidopsis and close model systems. Nevertheless, this approach has also highlighted a non-complete overlap between stress tolerance mechanisms in Arabidopsis and agricultural crops. Within a long-running research program aimed at identifying salt stress genetic determinants in potato by functional screening in Escherichia coli, we isolate...

  2. Resistance to Early-Life Stress in Mice: Effects of Genetic Background and Stress Duration

    Savignac, Hélène M.; Dinan, Timothy G.; Cryan, John F.

    2011-01-01

    Early-life stress can induce marked behavioral and physiological impairments in adulthood including cognitive deficits, depression, anxiety, and gastrointestinal dysfunction. Although robust rat models of early-life stress exist there are few established effective paradigms in the mouse. Genetic background and protocol parameters used are two critical variables in such model development. Thus we investigated the impact of two different early-life stress protocols in two commonly used inbred m...

  3. Coral thermal tolerance: tuning gene expression to resist thermal stress.

    Anthony J Bellantuono

    Full Text Available The acclimatization capacity of corals is a critical consideration in the persistence of coral reefs under stresses imposed by global climate change. The stress history of corals plays a role in subsequent response to heat stress, but the transcriptomic changes associated with these plastic changes have not been previously explored. In order to identify host transcriptomic changes associated with acquired thermal tolerance in the scleractinian coral Acropora millepora, corals preconditioned to a sub-lethal temperature of 3°C below bleaching threshold temperature were compared to both non-preconditioned corals and untreated controls using a cDNA microarray platform. After eight days of hyperthermal challenge, conditions under which non-preconditioned corals bleached and preconditioned corals (thermal-tolerant maintained Symbiodinium density, a clear differentiation in the transcriptional profiles was revealed among the condition examined. Among these changes, nine differentially expressed genes separated preconditioned corals from non-preconditioned corals, with 42 genes differentially expressed between control and preconditioned treatments, and 70 genes between non-preconditioned corals and controls. Differentially expressed genes included components of an apoptotic signaling cascade, which suggest the inhibition of apoptosis in preconditioned corals. Additionally, lectins and genes involved in response to oxidative stress were also detected. One dominant pattern was the apparent tuning of gene expression observed between preconditioned and non-preconditioned treatments; that is, differences in expression magnitude were more apparent than differences in the identity of genes differentially expressed. Our work revealed a transcriptomic signature underlying the tolerance associated with coral thermal history, and suggests that understanding the molecular mechanisms behind physiological acclimatization would be critical for the modeling of reefs

  4. Effects of silicon on plant resistance to environmental stresses: review

    Balakhnina, T.; Borkowska, A.

    2013-03-01

    The role of exogenous silicon in enhancing plant resistance to various abiotic stressors: salinity, drought, metal toxicities and ultraviolet radiation are presented. The data on possible involvement of silicon in reducing the reactive oxygen species generation, intensity of lipid peroxidation, and in some cases, increasing the activity of enzymes of the reactive oxygen species detoxificators: superoxide dismutase, ascorbate peroxidase, glutathione reductase, guaiacol peroxidase and catalase are analyzed.

  5. Plasticity in behavioural responses and resistance to temperature stress in Musca domestica

    Kjaersgaard, Anders; Blackenhorn, Wolf U.; Pertoldi, Cino;

    2015-01-01

    Organisms can respond to and cope with stressful environments in a number of ways including behavioural, morphological and physiological adjustments. To understand the role of behavioural traits in thermal adaptations we compared heat resistance, locomotor (walking and flying) activity, flight...... benign temperature, whereas the Spanish flies were able to stay active for longer at the stressful temperature. Population differences in behavioural traits and heat resistance were obtained using flies held for several generations in a laboratory common garden setting; therefore we suggest that exposure...

  6. Increased resistance to oxidative stress in transgenic plants that overexpress chloroplastic Cu/Zn superoxide dismutase.

    Gupta, A. S.; Heinen, J L; Holaday, A S; Burke, J. J.; Allen, R D

    1993-01-01

    Transgenic tobacco plants that express a chimeric gene that encodes chloroplast-localized Cu/Zn superoxide dismutase (SOD) from pea have been developed. To investigate whether increased expression of chloroplast-targeted SOD could alter the resistance of photosynthesis to environmental stress, these plants were subjected to chilling temperatures and moderate (500 mumol of quanta per m2 per s) or high (1500 mumol of quanta per m2 per s) light intensity. During exposure to moderate stress, tran...

  7. Insulin resistance improves metabolic and contractile efficiency in stressed rat heart

    Harmancey, Romain; Lam, Truong N.; Lubrano, Genna M.; Patrick H. Guthrie; Vela, Deborah; Taegtmeyer, Heinrich

    2012-01-01

    Insulin resistance is a prominent feature in heart failure, while hyperglycemia impairs cardiac contraction. We propose that decreased insulin-mediated glucose uptake by the heart preserves cardiac function in response to metabolic and hemodynamic stress. To test this hypothesis, we fed rats a high-sucrose diet (HSD). Energy substrate metabolism and cardiac work were determined ex vivo in a sequential protocol simulating metabolic and hemodynamic stress. Compared to chow-fed, control rats, HS...

  8. Listeria monocytogenes growth limits and stress resistance mechanisms

    Veen, van der, J.T.

    2008-01-01

    The food-borne pathogen Listeria monocytogenes is a Gram-positive facultative anaerobic rod, which is the causative agent of listeriosis. Due to the severity of the disease and the fact that its incidence is increasing in numerous European countries, L. monocytogenes is of great public health concern. This bacterium shows relatively high resistance to environmental insults compared with many other non-spore-forming food-borne pathogens. It is able to grow at low pH, at high salt concentration...

  9. Resistance to early-life stress in mice: effects of genetic background and stress duration

    Helene M. Savignac

    2011-04-01

    Full Text Available Early-life stress can induce marked behavioural and physiological impairments in adulthood including cognitive deficits, depression, anxiety and gastrointestinal dysfunction. Although robust rat models of early-life stress exist there are few established effective paradigms in the mouse. Genetic background and protocol parameters used are two critical variables in such model development.Thus we investigated the impact of two different early-life stress protocols in two commonly used inbred mouse strains. C57BL/6 and innately anxious BALB/c male mice were maternally deprived 3 hrs daily, either from postnatal day 1 to 14 (Protocol 1 or 6 to 10 (Protocol 2. Animals were assessed in adulthood for cognitive performance (spontaneous alternation behaviour test, anxiety (open field, light/dark box and elevated plus maze tests and depression-related behaviours (forced swim test in addition to stress-sensitive physiological changes. Overall, the results showed that early-life stressed mice from both strains displayed good cognitive ability and no elevations in anxiety. However, paradoxical changes occurred in C57BL/6 mice as the longer protocol (protocol 1 decreased anxiety in the light-dark box and increased exploration in the elevated plus maze. In BALB/c mice there were also limited effects of maternal separation with both separation protocols inducing reductions in stress-induced defecation and protocol 1 reducing the colon length. These data suggest that, independent of stress duration, mice from both strains were on the whole resilient to the maladaptive effects of early-life stress. Thus maternal-separation models of brain-gut axis dysfunction should rely on either different stressor protocols or other strains of mice.

  10. Insulin resistance in H pylori infection and its association with oxidative stress

    Mehmet Aslan; Mehmet Horoz; Yasar Nazligul; Cengiz Bolukbas; F Fusun Bolukbas; Sahbettin Selek; Hakim Celik; Ozcan Erel

    2006-01-01

    AIM:To determine the insulin resistance (IR) and oxidative status in H pylori infection and to find out if there is any relationship between these parameters and insulin resistance.METHODS:Fifty-five H pylori positive and 48 H pylori negative patients were enrolled. The homeostasis model assessment (HOMA) was used to assess insulin resistance. Serum total antioxidant capacity (TAC), total oxidant status (TOS) and oxidative stress index (OSI) were determined in all subjects.RESULTS:The total antioxidant capacity was significantly lower in H pylori positive group than in H pylori negative group (1.36 ± 0.33 and 1.70 ± 0.50,respectively; P < 0.001), while the total oxidant status and oxidative stress index were significantly higher in H pylori positive group than in H pylori negative group (6.79 ± 3.40 and 5.08 ± 0.95, and 5.42 ± 3.40 and 3.10± 0.92, respectively; P < 0.001). Insulin resistance was significantly higher in H pylori positive group than in H pylori negative group (6.92 ± 3.86 and 3.61 ± 1.67, respectively; P < 0.001). Insulin resistance was found to be significantly correlated with total antioxidant capacity (r= -0.251, P < 0.05), total oxidant status (r = 0.365, P <0.05), and oxidative stress index (r = 0.267, P < 0.05).CONCLUSION: Insulin resistance seems to be associated with increased oxidative stress in H pylori infection.Further studies are needed to clarify the mechanisms underlying this association and elucidate the effect of adding antioxidant vitamins to H pylori eradication therapy on insulin resistance during H pylori infection.

  11. The C. elegans healthspan and stress-resistance assay toolkit.

    Keith, Scott Alexander; Amrit, Francis Raj Gandhi; Ratnappan, Ramesh; Ghazi, Arjumand

    2014-08-01

    A wealth of knowledge on the genetic mechanisms that govern aging has emerged from the study of mutants that exhibit enhanced longevity and exceptional resilience to adverse environmental conditions. In these studies, lifespan has been an excellent proxy for establishing the rate of aging, but it is not always correlated with qualitative measures of healthy aging or 'healthspan'. Although the attributes of healthspan have been challenging to define, they share some universal features that are increasingly being incorporated into aging studies. Here we describe methods used to determine Caenorhabditis elegans healthspan. These include assessments of tissue integrity and functionality and resistance to a variety of biotic and abiotic stressors. We have chosen to include simple, rapid assays in this collection that can be easily undertaken in any C. elegans laboratory, and can be relied on to provide a preliminary but thorough insight into the healthspan of a population. PMID:24727065

  12. Effect of Residual Stress on the Wear Resistance of Thermal Spray Coatings

    Luo, W.; Selvadurai, U.; Tillmann, W.

    2016-01-01

    The wear resistance of thermal spray coatings mainly depends on coating properties such as the microstructure, hardness, and porosity, as well as on the residual stress in the coating. The residual stress is induced by a variety of influences e.g., temperature gradients, difference of the thermal expansion coefficient of the coating/substrate materials, and the geometry of the components. To investigate the residual stress, the impulse excitation technique was employed to measure the Young's and shear moduli. The residual stress was determined by the hole-drilling method and x-ray diffraction. Pin-on-Disk and Pin-on-Tube tests were used to investigate the wear behavior. After the wear tests, the wear volume was measured by means of a 3D-profilometer. The results show that the value of the residual stress can be modified by varying the coating thickness and the substrate geometry. The compressive stress in the HVOF-sprayed WC-Co coatings has a significant positive influence on the wear resistance whereas the tensile stress has a negative effect.

  13. Characterization of Resistance Gene Analogs in Musa acuminata Cultivars Contrasting in Resistance to Biotic Stresses

    The majority of commercial banana cultivars (Musa sp.) have evolved via asexual vegetative propagation, with diversity dependent upon somatic mutation. Restricted variation has resulted in a crops with little resistance to pests and disease, and conventional breeding efforts are limited due to limited viable seed production. Numerous disease resistance genes (R-genes / R-proteins) have been characterized in plants, recognizing and conferring resistance to bacteria, virus, fungi and nematodes. The identification and cloning of R-genes in Musa would contribute to germplasm improvement. To date, five main R-gene classes have been identified, based upon protein domains, with the most abundant coding for nucleotide-binding site-leucine-rich repeat (NBS-LRR) proteins. Primers designed from conserved protein motifs have enabled amplification of NBS homologues across diverse plant species. In Musa, our group has identified over 50 distinct NBS-LRR type resistance gene analogs (RGAs) in the resistant wild diploid M. acuminata Calcutta 4. The aim of this work was to characterize RGAs in M. acuminata cultivars contrasting in resistance to Black leaf Streak Disease. PCR amplification was conducted using DNA from M. acuminata cultivars Calcutta 4 (resistant) and Pisang Berlin (susceptible). Degenerate primers targeted sequences homologous to the NBS-LRR R-gene family. Following sequencing and processing of cloned PCR products, 63 out of a total of 136 high quality sequences showed homology to R-genes or RGAs. Phylogenetic analysis was conducted on deduced amino-acid sequences. Degenerate primers were also developed targeting an R-gene family of cytoplasmic serine-threonine (Ser/Thr) receptor-like kinases (RLKs) with extracellular LRRs, for application across cultivars. Studies are also planned for selection and full length sequencing of clones from M. acuminata and M. balbisiana BAC libraries containing novel RGAs characterized in this study, as an approach for complete R

  14. Characterization of resistance gene analogs in Musa acuminata cultivars contrasting in resistance to biotic stresses

    The majority of commercial banana cultivars (Musa sp.) have evolved via asexual vegetative propagation, with diversity dependent upon somatic mutation. Restricted variation has resulted in a crop with little resistance to pests and disease, and conventional breeding efforts are limited due to limited viable seed production. Numerous disease resistance genes (R-genes / R-proteins) have been characterized in plants, recognizing and conferring resistance to bacteria, virus, fungi and nematodes. The identification and cloning of R-genes in Musa would contribute to germplasm improvement. To date, five main R-gene classes have been identified, based upon protein domains, with the most abundant coding for nucleotidebinding site-leucine-rich repeat (NBS-LRR) proteins. Primers designed from conserved protein motifs have enabled amplification of NBS homologues across diverse plant species. In the case of Musa, our group has identified over 50 distinct NBS-LRR type resistance gene analogs (RGAs) in the resistant wild diploid M. acuminata Calcutta 4. The objective of this work was to characterize RGAs in M. acuminata cultivars contrasting in resistance to Black leaf Streak Disease. PCR amplification was conducted using DNA from M. acuminata cultivars Calcutta 4 (resistant) and Pisang Berlin (susceptible). Degenerate primers targeted sequences homologous to the NBS-LRR R-gene family. Following sequencing and processing of cloned PCR products, 63 out of a total of 136 high quality sequences showed homology to R-genes or RGAs. Phylogenetic analysis was conducted on deduced amino-acid sequences. Degenerate primers were also developed targeting an R-gene family of cytoplasmic serine-threonine (Ser/Thr) receptor-like kinases (RLKs) with extracellular LRRs, for application across cultivars. Studies are also planned for selection and full length sequencing of clones from M. acuminata and M. balbisiana BAC libraries containing novel RGAs characterized in this study, as an approach for

  15. Development of abiotic-stress resistant warm season trufgrasses by proton-beam irradiation

    Seo, Y. W.; Kim, J. Y.; Jeong, S. H. [Korea Univ., Seoul (Korea, Republic of)

    2007-04-15

    The direct use of mutation is a valuable approach to generate genetic variation in crop species by altering agronomically useful major traits. The proton beam, as a mutagen, was applied to improve resistance traits of Zoysia grass under various abiotic stresses. Proton beam was irradiated to mature dry seeds of Zenith (Zoysia grass), which is well-adapted to Korean climate, using a proton- accelerator with seven different doses (50, 100, 150, 200, 250, 300, 400 Gy). Individual seedling of M1 plant was transplanted from the seed bed and allowed to reach appropriate plant mass. Clones that showed superior growth were chosen and transplanted to pots for further clone propagation and field evaluation. Growth characteristics of turfgrass, such as plant height, leaf length, leaf width, number of tiller were evaluated ninety days after sowing. Although large variation within each dose, noticeable differences were found among different irradiated doses. Most of the mutant clones derived from the irradiation treatment showed more vigorous growth than the control plants. RAPD (Random Amplified Polymorphic DNA) and AFLP (Amplified Fragment Length Polymorphism) methods were conducted to analyze genomic variations associated with proton beam irradiation. In order to establish selection criteria for selection of salt-stress resistance plants, an in vitro method that is able to select salt-stress resistant mutants in liquid media without ambient disturbances. Total 647 predominance clones that were considered as abiotic stress resistant mutants were transplanted to the field for further evaluation.

  16. Development of abiotic-stress resistant warm season trufgrasses by proton-beam irradiation

    The direct use of mutation is a valuable approach to generate genetic variation in crop species by altering agronomically useful major traits. The proton beam, as a mutagen, was applied to improve resistance traits of Zoysia grass under various abiotic stresses. Proton beam was irradiated to mature dry seeds of Zenith (Zoysia grass), which is well-adapted to Korean climate, using a proton- accelerator with seven different doses (50, 100, 150, 200, 250, 300, 400 Gy). Individual seedling of M1 plant was transplanted from the seed bed and allowed to reach appropriate plant mass. Clones that showed superior growth were chosen and transplanted to pots for further clone propagation and field evaluation. Growth characteristics of turfgrass, such as plant height, leaf length, leaf width, number of tiller were evaluated ninety days after sowing. Although large variation within each dose, noticeable differences were found among different irradiated doses. Most of the mutant clones derived from the irradiation treatment showed more vigorous growth than the control plants. RAPD (Random Amplified Polymorphic DNA) and AFLP (Amplified Fragment Length Polymorphism) methods were conducted to analyze genomic variations associated with proton beam irradiation. In order to establish selection criteria for selection of salt-stress resistance plants, an in vitro method that is able to select salt-stress resistant mutants in liquid media without ambient disturbances. Total 647 predominance clones that were considered as abiotic stress resistant mutants were transplanted to the field for further evaluation

  17. Biochemical basis of the high resistance to oxidative stress in Dictyostelium discoideum

    Bandhana Katoch; Rasheedunnisa Begum

    2003-09-01

    Aerobic organisms experience oxidative stress due to generation of reactive oxygen species during normal aerobic metabolism. In addition, several chemicals also generate reactive oxygen species which induce oxidative stress. Thus oxidative stress constitutes a major threat to organisms living in aerobic environments. Programmed cell death or apoptosis is a physiological mechanism of cell death, that probably evolved with multicellularity, and is indispensable for normal growth and development. Dictyostelium discoideum, an eukaryotic developmental model, shows both unicellular and multicellular forms in its life cycle and exhibits apparent caspase-independent programmed cell death, and also shows high resistance to oxidative stress. An attempt has been made to investigate the biochemical basis for high resistance of D. discoideum cell death induced by different oxidants. Dose-dependent induction of cell death by exogenous addition of hydrogen peroxide (H2O2), in situ generation of H2O2 by hydroxylamine, and nitric oxide (NO) generation by sodium nitroprusside treatment in D. discoideum were studied. The AD50 doses (concentration of the oxidants cusing 50% of the cells to die) after 24 h of treatment were found to be 0.45 mM, 4 mM and 1 mM, respectively. Studies on enzymatic antioxidant status of D. discoideum when subjected to oxidative stress, NO and nutrient stress reveal that superoxide dismutase and catalase were unchanged; a significant induction of glutathione peroxidase was observed. Interestingly, oxidative stress-induced lipid membrane peroxidative damage could not be detected. The results shed light on the biochemical basis for the observed high resistance to oxidative stress in D. discoideum.

  18. Stress corrosion cracking resistance of aluminum alloy 7000 series after two-step aging

    Jegdić Bore V.

    2015-01-01

    Full Text Available The effect of one step-and a new (short two-step aging on the resistance to stress corrosion cracking of an aluminum alloy 7000 series was investigated, using slow strain rate test and fracture mechanics method. Aging level in the tested alloy was evaluated by means of scanning electron microscopy and measurements of electrical resistivity. It was shown that the alloy after the new two-step aging is significantly more resistant to stress corrosion cracking. Values of tensile properties and fracture toughness are similar for both thermal states. Processes that take place at the crack tip have been considered. The effect of the testing solution temperature on the crack growth rate on the plateau was determined. Two values of the apparent activation energy were obtained. These values correspond to different processes that control crack growth rate on the plateau at higher and lower temperatures. [Projekat Ministarstva nauke Republike Srbije, br. TR 34028 i br. TR 34016

  19. Influence of the clay in the stress cracking resistance of PET; Influencia de silicatos em camadas na resistencia ao 'stress cracking' do PET

    Teofilo, Edvania T. [Programa de Pos-Graduacao em Ciencia e Engenharia de Materiais, Universidade Federal de Campina Grande, PB (Brazil); Silva, Emanuela S.; Silva, Suedina M.L.; Rabello, Marcelo S., E-mail: marcelo@dema.ufcg.edu.b [Unidade Academica de Engenharia de Materiais, Universidade Federal de Campina Grande, PB (Brazil)

    2011-07-01

    The environmental stress cracking resistance in PET and hybrid PET/clay were conducted under stress relaxation test. X-ray diffraction analysis show that was obtained immiscible system. In the absence of aggressive fluids the hybrid exhibited higher relaxation rates than the PET. Already in contact with aggressive fluids showed a similar or lower relaxation rate than the PET, being more resistant. Suggesting that the clay, though not interlayer, interferes with the distribution of the stress cracking agent. Thus, the barrier effect caused by the clay was more significant than the stress concentration caused by it. (author)

  20. Stress concentrator effect on corrosion resistance of welded joints of zirconium - 2.5% niobium alloys

    Considered is the effect of notches and poor penetrations of 10 and 20% pipeline wall thickness made of Zr - 2.5% Nb alloy on corrosion resistance. Stress concentrator effects have been estimated on the basis of results of cyclic tests in 3% NaCl and pressure tests in water-vapor medium at 300 deg C and 85 atm during 1200 h. Estimated are critical strains and corresponding stresses for basic and a weldmetals. Stress concentrators are shown to low the level of critical stresses of corrosion-mechanical fracture initiation. In water-vapor mixture there found is a corrosion in some zones of welded joint heated in a process of welding over 600 deg C. For such zones registered is the effect of structural-chemical changes, caused by welding

  1. Effect of myricetin, pyrogallol, and phloroglucinol on yeast resistance to oxidative stress.

    Mendes, Vanda; Vilaça, Rita; de Freitas, Victor; Ferreira, Pedro Moradas; Mateus, Nuno; Costa, Vítor

    2015-01-01

    The health beneficial effects of dietary polyphenols have been attributed to their intrinsic antioxidant activity, which depends on the structure of the compound and number of hydroxyl groups. In this study, the protective effects of pyrogallol, phloroglucinol, and myricetin on the yeast Saccharomyces cerevisiae were investigated. Pyrogallol and myricetin, which have a pyrogallol structure in the B ring, increased H2O2 resistance associated with a reduction in intracellular oxidation and protein carbonylation, whereas phloroglucinol did not exert protective effects. The acquisition of oxidative stress resistance in cells pretreated with pyrogallol and myricetin was not associated with an induction of endogenous antioxidant defences as assessed by the analysis of superoxide dismutase and catalase activities. However, myricetin, which provided greater stress resistance, prevented H2O2-induced glutathione oxidation. Moreover, myricetin increased the chronological lifespan of yeast lacking the mitochondrial superoxide dismutase (Sod2p), which exhibited a premature aging phenotype and oxidative stress sensitivity. These findings show that the presence of hydroxyl groups in the ortho position of the B ring in pyrogallol and myricetin contributes to the antioxidant protection afforded by these compounds. In addition, myricetin may alleviate aging-induced oxidative stress, particularly when redox homeostasis is compromised due to downregulation of endogenous defences present in mitochondria. PMID:26000072

  2. Effect of Myricetin, Pyrogallol, and Phloroglucinol on Yeast Resistance to Oxidative Stress

    Vanda Mendes

    2015-01-01

    Full Text Available The health beneficial effects of dietary polyphenols have been attributed to their intrinsic antioxidant activity, which depends on the structure of the compound and number of hydroxyl groups. In this study, the protective effects of pyrogallol, phloroglucinol, and myricetin on the yeast Saccharomyces cerevisiae were investigated. Pyrogallol and myricetin, which have a pyrogallol structure in the B ring, increased H2O2 resistance associated with a reduction in intracellular oxidation and protein carbonylation, whereas phloroglucinol did not exert protective effects. The acquisition of oxidative stress resistance in cells pretreated with pyrogallol and myricetin was not associated with an induction of endogenous antioxidant defences as assessed by the analysis of superoxide dismutase and catalase activities. However, myricetin, which provided greater stress resistance, prevented H2O2-induced glutathione oxidation. Moreover, myricetin increased the chronological lifespan of yeast lacking the mitochondrial superoxide dismutase (Sod2p, which exhibited a premature aging phenotype and oxidative stress sensitivity. These findings show that the presence of hydroxyl groups in the ortho position of the B ring in pyrogallol and myricetin contributes to the antioxidant protection afforded by these compounds. In addition, myricetin may alleviate aging-induced oxidative stress, particularly when redox homeostasis is compromised due to downregulation of endogenous defences present in mitochondria.

  3. Stress proteins and phytohormones: their role in formation of plant resistance

    Full text: Using the disc-electrophoresis methods, we have studied protein biosynthesis of different plants, including 11 species of Orchidaceae, some other tropical and subtropical plants, 9 different fruit plants, and 4 cultivars of Triticum aestivum L. under stresses factors such as high and low temperature, clinostating, radioactive irradiation and osmotic shock. Specific and unspecific reactions of plants protein system on stresses were found. De novo synthesis of 35 and 45 kD polypeptides were observed in total and mitochondrial proteins fractions after heat-shock and radioactive irradiation. This suggests that mitochondries participate in formation of plant resistance. Intensive synthesis of ABA revealed as the universal reaction of all studied plants on action of different kinds of stresses. Specific changes in balance of phytohormones were found under different stresses. We observed the correlation between endogenous ABA, IAA and cytokinin level and plant resistance. We also found the interaction between the process of biosynthesis of proteins and phytohormone balance, as well as their direct participation in formation of plant resistance. (author)

  4. Diet-induced obesity induces endoplasmic reticulum stress and insulin resistance in the amygdala of rats.

    Castro, Gisele; C Areias, Maria Fernanda; Weissmann, Lais; Quaresma, Paula G F; Katashima, Carlos K; Saad, Mario J A; Prada, Patricia O

    2013-01-01

    Insulin acts in the hypothalamus, decreasing food intake (FI) by the IR/PI3K/Akt pathway. This pathway is impaired in obese animals and endoplasmic reticulum (ER) stress and low-grade inflammation are possible mechanisms involved in this impairment. Here, we highlighted the amygdala as an important brain region for FI regulation in response to insulin. This regulation was dependent on PI3K/AKT pathway similar to the hypothalamus. Insulin was able to decrease neuropeptide Y (NPY) and increase oxytocin mRNA levels in the amygdala via PI3K, which may contribute to hypophagia. Additionally, obese rats did not reduce FI in response to insulin and AKT phosphorylation was decreased in the amygdala, suggesting insulin resistance. Insulin resistance was associated with ER stress and low-grade inflammation in this brain region. The inhibition of ER stress with PBA reverses insulin action/signaling, decreases NPY and increases oxytocin mRNA levels in the amygdala from obese rats, suggesting that ER stress is probably one of the mechanisms that induce insulin resistance in the amygdala. PMID:24251109

  5. Diet-induced obesity induces endoplasmic reticulum stress and insulin resistance in the amygdala of rats☆

    Castro, Gisele; C. Areias, Maria Fernanda; Weissmann, Lais; Quaresma, Paula G.F.; Katashima, Carlos K.; Saad, Mario J.A.; Prada, Patricia O.

    2013-01-01

    Insulin acts in the hypothalamus, decreasing food intake (FI) by the IR/PI3K/Akt pathway. This pathway is impaired in obese animals and endoplasmic reticulum (ER) stress and low-grade inflammation are possible mechanisms involved in this impairment. Here, we highlighted the amygdala as an important brain region for FI regulation in response to insulin. This regulation was dependent on PI3K/AKT pathway similar to the hypothalamus. Insulin was able to decrease neuropeptide Y (NPY) and increase oxytocin mRNA levels in the amygdala via PI3K, which may contribute to hypophagia. Additionally, obese rats did not reduce FI in response to insulin and AKT phosphorylation was decreased in the amygdala, suggesting insulin resistance. Insulin resistance was associated with ER stress and low-grade inflammation in this brain region. The inhibition of ER stress with PBA reverses insulin action/signaling, decreases NPY and increases oxytocin mRNA levels in the amygdala from obese rats, suggesting that ER stress is probably one of the mechanisms that induce insulin resistance in the amygdala. PMID:24251109

  6. Inclusion of copepod Acartia tonsa nauplii in the feeding of Centropomus undecimalis larvae increases stress resistance

    Wanessa de Melo-Costa

    2015-09-01

    Full Text Available This research represents the first result of studies of the common snook Centropomus undecimalis larvae from broodstock matured in captivity in Brazil. The aim of this study was to evaluate if the inclusion of Acartia tonsa nauplii improves stress resistance of common snook larvae. The larvae were fed with: rotifers Brachionus plicatilis (10 to 15 mL-1; A. tonsa nauplii (0.25 to 0.5 mL-1 and rotifers (5 to 7.5 mL-1, and A. tonsa nauplii (0.12 to 0.25 mL-1. The average percentage of survival of the treatments was 11.9%. At 20 days of age, larvae were subjected to thermal stress. Subsequently, the stress resistance was evaluated. Common snook larvae fed B. plicatilis+A. tonsa reached a higher weight and length (7.5 ± 0.00 mg and 9.1 ± 0.23 mm, respectively and resisted more heat stress (87.4% than larvae fed other foods, indicating that the feed mixture is satisfactory as a starter diet for larvae of common snook. However, more research is needed to confirm these results.

  7. Electrical resistivity change in amorphous Ta42Si13N45 films by stress relaxation

    In a first experiment, a reactively sputtered amorphous Ta42Si13N45 film about 260 nm thick deposited on a flat and smooth alumina substrate was thermally annealed in air for 30 min and let cooled again repeatedly at successively higher temperatures from 200 to 500 C. This treatment successively and irreversibly increases the room temperature resistivity of the film monotonically from its initial value of 670 μΩ cm to a maximum of 705 μΩ cm (+5.2 %). Subsequent heat treatments at temperatures below 500 C and up to 6 h have no further effect on the room temperature resistivity. The new value remains unchanged after 3.8 years of storage at room temperature. In a second experiment, the evolution of the initially compressive stress of a film similarly deposited by reactive sputtering on a 2-inch silicon wafer was measured by tracking the wafer curvature during similar thermal annealing cycles. A similar pattern of irreversible and reversible changes of stress was observed as for the film resistivity. Transmission electron micrographs and secondary ion mass profiles of the film taken before and after thermal annealing in air establish that both the structure and the composition of the film scarcely change during the annealing cycles. We reason that the film stress is implicated in the resistivity change. In particular, to interpret the observations, a model is proposed where the interface between the film and the substrate is mechanically unyielding. (orig.)

  8. Resistance to Aspergillus flavus in maize and peanut: Molecular biology, breeding, environmental stress, and future perspectives

    Jake C. Fountain

    2015-06-01

    Full Text Available The colonization of maize (Zea mays L. and peanut (Arachis hypogaea L. by the fungal pathogen Aspergillus flavus results in the contamination of kernels with carcinogenic mycotoxins known as aflatoxins leading to economic losses and potential health threats to humans. The regulation of aflatoxin biosynthesis in various Aspergillus spp. has been extensively studied, and has been shown to be related to oxidative stress responses. Given that environmental stresses such as drought and heat stress result in the accumulation of reactive oxygen species (ROS within host plant tissues, host-derived ROS may play an important role in cross-kingdom communication between host plants and A. flavus. Recent technological advances in plant breeding have provided the tools necessary to study and apply knowledge derived from metabolomic, proteomic, and transcriptomic studies in the context of productive breeding populations. Here, we review the current understanding of the potential roles of environmental stress, ROS, and aflatoxin in the interaction between A. flavus and its host plants, and the current status in molecular breeding and marker discovery for resistance to A. flavus colonization and aflatoxin contamination in maize and peanut. We will also propose future directions and a working model for continuing research efforts linking environmental stress tolerance and aflatoxin contamination resistance in maize and peanut.

  9. Ultrasonic Impact Treatment to Improve Stress Corrosion Cracking Resistance of Welded Joints of Aluminum Alloy

    Yu, J.; Gou, G.; Zhang, L.; Zhang, W.; Chen, H.; Yang, Y. P.

    2016-07-01

    Stress corrosion cracking is one of the major issues for welded joints of 6005A-T6 aluminum alloy in high-speed trains. High residual stress in the welded joints under corrosion results in stress corrosion cracking. Ultrasonic impact treatment was used to control the residual stress of the welded joints of 6005A-T6 aluminum alloy. Experimental tests show that ultrasonic impact treatment can induce compressive longitudinal and transverse residual stress in the welded joint, harden the surface, and increase the tensile strength of welded joints. Salt-fog corrosion tests were conducted for both an as-welded sample and an ultrasonic impact-treated sample. The surface of the treated sample had far fewer corrosion pits than that of the untreated sample. The treated sample has higher strength and lower tensile residual stress than the untreated sample during corrosion. Therefore, ultrasonic impact treatment is an effective technique to improve the stress corrosion cracking resistance of the welded joints of 6005A-T6 aluminum alloy.

  10. Effect of T-stress on the cleavage crack growth resistance resulting from plastic flow

    Tvergaard, Viggo

    1998-01-01

    , the materials show crack growth resistance. It is shown here that the resistance is strongly dependent on the value of the non-singular T-stress, acting parallel to the crack plane. The numerical technique employed makes use of a thin dislocation-free strip of elastic material inside which the crack......Crack growth is studied numerically for cases where fracture occurs by atomic separation, sc that the length scale of the fracture process is typically much smaller than the dislocation spacing. Thus, the crack growth mechanism is brittle, but due to plastic flow at some distance from the crack tip...

  11. Loss of NDG-4 extends lifespan and stress resistance in Caenorhabditis elegans

    Brejning, Jeanette; Nørgaard, Steffen; Schøler, Lone Vedel;

    2014-01-01

    NDG-4 is a predicted transmembrane acyltransferase protein that acts in the distribution of lipophilic factors. Consequently, ndg-4 mutants lay eggs with a pale appearance due to lack of yolk, and they are resistant to sterility caused by dietary supplementation with the long-chain omega-6...... protein results in increased organismal stress resistance and lifespan. When NDG-4 function and insulin/IGF-1 signaling are reduced simultaneously, maximum lifespan is increased almost fivefold. Thus, longevity conferred by mutation of ndg-4 is partially overlapping with insulin signaling. The nuclear...

  12. Transcriptome Profiling Revealed Stress-Induced and Disease Resistance Genes Up-Regulated in PRSV Resistant Transgenic Papaya.

    Fang, Jingping; Lin, Aiting; Qiu, Weijing; Cai, Hanyang; Umar, Muhammad; Chen, Rukai; Ming, Ray

    2016-01-01

    Papaya is a productive and nutritious tropical fruit. Papaya Ringspot Virus (PRSV) is the most devastating pathogen threatening papaya production worldwide. Development of transgenic resistant varieties is the most effective strategy to control this disease. However, little is known about the genome-wide functional changes induced by particle bombardment transformation. We conducted transcriptome sequencing of PRSV resistant transgenic papaya SunUp and its PRSV susceptible progenitor Sunset to compare the transcriptional changes in young healthy leaves prior to infection with PRSV. In total, 20,700 transcripts were identified, and 842 differentially expressed genes (DEGs) randomly distributed among papaya chromosomes. Gene ontology (GO) category analysis revealed that microtubule-related categories were highly enriched among these DEGs. Numerous DEGs related to various transcription factors, transporters and hormone biosynthesis showed clear differences between the two cultivars, and most were up-regulated in transgenic papaya. Many known and novel stress-induced and disease-resistance genes were most highly expressed in SunUp, including MYB, WRKY, ERF, NAC, nitrate and zinc transporters, and genes involved in the abscisic acid, salicylic acid, and ethylene signaling pathways. We also identified 67,686 alternative splicing (AS) events in Sunset and 68,455 AS events in SunUp, mapping to 10,994 and 10,995 papaya annotated genes, respectively. GO enrichment for the genes displaying AS events exclusively in Sunset was significantly different from those in SunUp. Transcriptomes in Sunset and transgenic SunUp are very similar with noteworthy differences, which increased PRSV-resistance in transgenic papaya. No detrimental pathways and allergenic or toxic proteins were induced on a genome-wide scale in transgenic SunUp. Our results provide a foundation for unraveling the mechanism of PRSV resistance in transgenic papaya. PMID:27379138

  13. Polyunsaturated Branched-Chain Fatty Acid Geranylgeranoic Acid Induces Unfolded Protein Response in Human Hepatoma Cells.

    Chieko Iwao

    Full Text Available The acyclic diterpenoid acid geranylgeranoic acid (GGA has been reported to induce autophagic cell death in several human hepatoma-derived cell lines; however, the molecular mechanism for this remains unknown. In the present study, several diterpenoids were examined for ability to induce XBP1 splicing and/or lipotoxicity for human hepatoma cell lines. Here we show that three groups of diterpenoids emerged: 1 GGA, 2,3-dihydro GGA and 9-cis retinoic acid induce cell death and XBP1 splicing; 2 all-trans retinoic acid induces XBP1 splicing but little cell death; and 3 phytanic acid, phytenic acid and geranylgeraniol induce neither cell death nor XBP1 splicing. GGA-induced ER stress/ unfolded protein response (UPR and its lipotoxicity were both blocked by co-treatment with oleic acid. The blocking activity of oleic acid for GGA-induced XBP1 splicing was not attenuated by methylation of oleic acid. These findings strongly suggest that GGA at micromolar concentrations induces the so-called lipid-induced ER stress response/UPR, which is oleate-suppressive, and shows its lipotoxicity in human hepatoma cells.

  14. The stress of maternal separation causes misprogramming in the postnatal maturation of rat resistance arteries.

    Reho, John J; Fisher, Steven A

    2015-11-01

    We examined the effect of stress in the first 2 wk of life induced by brief periods of daily maternal separation on developmental programming of rat small resistance mesenteric arteries (MAs). In MAs of littermate controls, mRNAs encoding mediators of vasoconstriction, including the α1a-adrenergic receptor, smooth muscle myosin heavy chain, and CPI-17, the inhibitory subunit of myosin phosphatase, increased from after birth through sexual [postnatal day (PND) 35] and full maturity, up to ∼80-fold, as measured by quantitative PCR. This was commensurate with two- to fivefold increases in maximum force production to KCl depolarization, calcium, and the α-adrenergic agonist phenylephrine, and increasing systolic blood pressure. Rats exposed to maternal separation stress as neonates had markedly accelerated trajectories of maturation of arterial contractile gene expression and function measured at PND14 or PND21 (weaning), 1 wk after the end of the stress protocol. This was suppressed by the α-adrenergic receptor blocker terazosin (0.5 mg·kg ip(-1)·day(-1)), indicating dependence on stress activation of sympathetic signaling. Due to the continued maturation of MAs in control rats, by sexual maturity (PND35) and into adulthood, no differences were observed in arterial function or response to a second stressor in rats stressed as neonates. Thus early life stress misprograms resistance artery smooth muscle, increasing vasoconstrictor function and blood pressure. This effect wanes in later stages, suggesting plasticity during arterial maturation. Further studies are indicated to determine whether stress in different periods of arterial maturation may cause misprogramming persisting through maturity and the potential salutary effect of α-adrenergic blockade in suppression of this response. PMID:26371173

  15. Angiotensin II receptor blocker ameliorates stress-induced adipose tissue inflammation and insulin resistance.

    Motoharu Hayashi

    Full Text Available A strong causal link exists between psychological stress and insulin resistance as well with hypertension. Meanwhile, stress-related responses play critical roles in glucose metabolism in hypertensive patients. As clinical trials suggest that angiotensin-receptor blocker delays the onset of diabetes in hypertensive patients, we investigated the effects of irbesartan on stress-induced adipose tissue inflammation and insulin resistance. C57BL/6J mice were subjected to 2-week intermittent restraint stress and orally treated with vehicle, 3 and 10 mg/kg/day irbesartan. The plasma concentrations of lipid and proinflammatory cytokines [Monocyte Chemoattractant Protein-1 (MCP-1, tumor necrosis factor-α, and interleukin-6] were assessed with enzyme-linked immunosorbent assay. Monocyte/macrophage accumulation in inguinal white adipose tissue (WAT was observed with CD11b-positive cell counts and mRNA expressions of CD68 and F4/80 using immunohistochemistry and RT-PCR methods respectively. The mRNA levels of angiotensinogen, proinflammatory cytokines shown above, and adiponectin in WAT were also assessed with RT-PCR method. Glucose metabolism was assessed by glucose tolerance tests (GTTs and insulin tolerance tests, and mRNA expression of insulin receptor substrate-1 (IRS-1 and glucose transporter 4 (GLUT4 in WAT. Restraint stress increased monocyte accumulation, plasma free fatty acids, expression of angiotensinogen and proinflammatory cytokines including MCP-1, and reduced adiponectin. Irbesartan reduced stress-induced monocyte accumulation in WAT in a dose dependent manner. Irbesartan treatment also suppressed induction of adipose angiotensinogen and proinflammatory cytokines in WAT and blood, and reversed changes in adiponectin expression. Notably, irbesartan suppressed stress-induced reduction in adipose tissue weight and free fatty acid release, and improved insulin tolerance with restoration of IRS-1 and GLUT4 mRNA expressions in WAT. The results

  16. Ozone phytotoxicity in relation to stress ethylene evolution and stomatal resistance in cowpea (Vigna unguiculata) cultivars

    Adepipe, N.O.; Tingey, D.T.

    1979-01-01

    In greenhouse experiments, the ozone sensitivities of three cowpea cultivars differing in growth habits and some physiological traits were determined and related to stress ethylene production and leaf diffusive resistance. The cultivars were more sensitive at the 3-leaf than at the 2-leaf stages of growth. There was no consistent leaf injury at less than 0.50 ..mu..l/l of ozone for 2 hr. At an ozone concentration of 1.0 ..mu..l/l for 2 hr. the cultivar Adzuki exhibited marked leaf injury, amounting to over 80% symptom coverage of the leaf surface while New Era and Ife Brown sustained leaf injury maxima of 58 and 35% respectively. Stress ethylene production did not differ among the cultivars. While ozone increased stomatal diffusive resistance in all cultivars, there were not significant differences among the cultivars.

  17. Multiple roles of putrescine and spermidine in stress resistance and virulence of Salmonella enterica serovar Typhimurium

    Espinel, Irene cartas; Guerra, Priscila Regina; Jelsbak, Lotte

    2016-01-01

    infections of mice. Using a S. Typhimurium mutant defective for putrescine and spermidine biosynthesis, we show that polyamines are essential for coping with reactive nitrogen species, possibly linking polyamines to increased intracellular stress resistance. However, using a mouse model defective for nitric....... Typhimurium virulence is the ability to survive and replicate inside macrophages and resisting the antimicrobial attacks in the form of oxidative and nitrosative stress elicited from these cells. In the present study, we have investigated the role of polyamines in intracellular survival and systemic...... retained ability to produce and import putrescine. Interestingly, in this mutant we observe a strong attenuation of virulence during infection of mice proficient and deficient for nitric oxide production suggesting that spermidine, specifically, is essential for virulence of S. Typhimurium....

  18. The Fungal Pathogen Aspergillus fumigatus Regulates Growth, Metabolism, and Stress Resistance in Response to Light

    Fuller, Kevin K.; Ringelberg, Carol S.; Loros, Jennifer J.; Dunlap, Jay C

    2013-01-01

    ABSTRACT Light is a pervasive environmental factor that regulates development, stress resistance, and even virulence in numerous fungal species. Though much research has focused on signaling pathways in Aspergillus fumigatus, an understanding of how this pathogen responds to light is lacking. In this report, we demonstrate that the fungus does indeed respond to both blue and red portions of the visible spectrum. Included in the A. fumigatus light response is a reduction in conidial germinatio...

  19. Heat treatment of NiCrFe alloy 600 to optimize resistance to intergranular stress corrosion

    Steeves, A.F.; Bibb, A.E.

    A process of producing a NiCrFe alloy having a high resistance to stress corrosion cracking comprises heating a NiCrFe alloy to a temperature sufficient to enable the carbon present in the alloy body in the form of carbide deposits to enter into solution, rapidly cooling the alloy body, and heating the cooled body to a temperature between 1100 to 1500/sup 0/F for about 1 to 30 hours.

  20. FUNCTION OF HYDRAULIC AND CHEMICAL WATER STRESS SIGNALIZATION IN EVALUATION OF DROUGHT RESISTANCE OF JUVENILE PLANTS

    OLŠOVSKÁ, K.; BRESTIČ, M.

    2002-01-01

    In laboratory hydroponic experiments with spring barley genotypes the juvenile plants with 5 leaves were tested for their physiological responses to osmotic stress evoked by blocking the water uptake in roots by polyethylenglycol (PEG-6000) and to exogenous abscisic acid (ABA) applied in the nutrient solution which inhibits the stomata opening. Results from the measurements of leaf diffusion resistance, relative water content, transpiration and leaf elongation rates show dominant role of chem...

  1. ENHANCEMENT OF CHLORIDE RESISTANCE OF PRE-STRESSED CONCRETE SHEET PILE BY BLAST FURNACE SLAG

    Irmawaty, Rita

    2012-01-01

    Chloride-induced corrosion is one of the main mechanisms of deterioration affecting the long-term performance of concrete structures. In Japan, a large majority of structures are built either near the costal or indirect contact with seawater. The durability of reinforced or pre-stressed concrete structure depends on the resistance of concrete to chloride penetration. Naturally concrete provides physical and chemical protection to the reinforcing steel from chloride penetrating. The chloride ...

  2. 2-deoxy-D-glucose-induced metabolic stress enhances resistance to Listeria monocytogenes infection in mice

    Miller, E. S.; Bates, R. A.; Koebel, D. A.; Fuchs, B. B.; Sonnenfeld, G.

    1998-01-01

    Exposure to different forms of psychological and physiological stress can elicit a host stress response, which alters normal parameters of neuroendocrine homeostasis. The present study evaluated the influence of the metabolic stressor 2-deoxy-D-glucose (2-DG; a glucose analog, which when administered to rodents, induces acute periods of metabolic stress) on the capacity of mice to resist infection with the facultative intracellular bacterial pathogen Listeria monocytogenes. Female BDF1 mice were injected with 2-DG (500 mg/kg b. wt.) once every 48 h prior to, concurrent with, or after the onset of a sublethal dose of virulent L. monocytogenes. Kinetics of bacterial growth in mice were not altered if 2-DG was applied concurrently or after the start of the infection. In contrast, mice exposed to 2-DG prior to infection demonstrated an enhanced resistance to the listeria challenge. The enhanced bacterial clearance in vivo could not be explained by 2-DG exerting a toxic effect on the listeria, based on the results of two experiments. First, 2-DG did not inhibit listeria replication in trypticase soy broth. Second, replication of L. monocytogenes was not inhibited in bone marrow-derived macrophage cultures exposed to 2-DG. Production of neopterin and lysozyme, indicators of macrophage activation, were enhanced following exposure to 2-DG, which correlated with the increased resistance to L. monocytogenes. These results support the contention that the host response to 2-DG-induced metabolic stress can influence the capacity of the immune system to resist infection by certain classes of microbial pathogens.

  3. Macronutrient intake induces oxidative and inflammatory stress: potential relevance to atherosclerosis and insulin resistance

    Dandona, Paresh; Ghanim, Husam; Chaudhuri, Ajay; Dhindsa, Sandeep; Kim, Sung Soo

    2010-01-01

    With the global increase in the epidemic of obesity and type 2 diabetes with a concomitant increase in atherosclerotic disease, an investigation into the effects of various macronutrients and food products has become necessary. Such investigation will allow us to better understand the relationship between the intake of various macronutrients and the pathogenesis of mechanisms underlying the regulation of insulin sensitivity and resistance, oxidative stress and inflammation, the regulation of ...

  4. Effect of Aging on Fracture Toughness and Stress Corrosion Cracking Resistance of Forged 7475 Aluminum Alloy

    LI Hongying; GENG Jinfeng; DONG Xianjuan; WANG Changjian; ZHENG Feng

    2007-01-01

    The effects of two-stage aging and retrogression and reaging heat treatment on the fracture toughness and stress corrosion cracking resistance of 7475 alloy were studied. The fracture toughness, conductivity and strength of samples of nine groups under duplex aging conditions and three retrogression and reaging heat treatments were also measured. Incorporating the microstructure and property, we found that when the condition of the first order aging kept identical, the fracture toughness and stress corrosion cracking resistance increase with aging time and the second aging temperature. The optimal treatment conditions are (115℃×7h+185℃×13h) among all tested two-stage aging treatments.Although the 7475 alloy treated by RRA method shows the highest strength and its stress corrosion cracking resistance after twenty minutes retrogression can also reach the same level as those by the optimal treatment of (115℃×7h+185℃×13h),the fracture toughness is even low.

  5. Decreased Skin-Mediated Detoxification Contributes to Oxidative Stress and Insulin Resistance

    Xing-Xing Liu

    2012-01-01

    Full Text Available The skin, the body's largest organ, plays an important role in the biotransformation/detoxification and elimination of xenobiotics and endogenous toxic substances, but its role in oxidative stress and insulin resistance is unclear. We investigated the relationship between skin detoxification and oxidative stress/insulin resistance by examining burn-induced changes in nicotinamide degradation. Rats were divided into four groups: sham-operated, sham-nicotinamide, burn, and burn-nicotinamide. Rats received an intraperitoneal glucose injection (2 g/kg with (sham-nicotinamide and burn-nicotinamide groups or without (sham-operated and burn groups coadministration of nicotinamide (100 mg/kg. The results showed that the mRNA of all detoxification-related enzymes tested was detected in sham-operated skin but not in burned skin. The clearance of nicotinamide and N1-methylnicotinamide in burned rats was significantly decreased compared with that in sham-operated rats. After glucose loading, burn group showed significantly higher plasma insulin levels with a lower muscle glycogen level than that of sham-operated and sham-nicotinamide groups, although there were no significant differences in blood glucose levels over time between groups. More profound changes in plasma H2O2 and insulin levels were observed in burn-nicotinamide group. It may be concluded that decreased skin detoxification may increase the risk for oxidative stress and insulin resistance.

  6. The Ablation of Mitochondrial Protein Phosphatase Pgam5 Confers Resistance Against Metabolic Stress

    Shiori Sekine

    2016-03-01

    Full Text Available Phosphoglycerate mutase family member 5 (PGAM5 is a mitochondrial protein phosphatase that has been reported to be involved in various stress responses from mitochondrial quality control to cell death. However, its roles in vivo are largely unknown. Here, we show that Pgam5-deficient mice are resistant to several metabolic insults. Under cold stress combined with fasting, Pgam5-deficient mice better maintained body temperature than wild-type mice and showed an extended survival rate. Serum triglycerides and lipid content in brown adipose tissue (BAT, a center of adaptive thermogenesis, were severely reduced in Pgam5-deficient mice. Moreover, although Pgam5 deficiency failed to maintain proper mitochondrial integrity in BAT, it reciprocally resulted in the dramatic induction of fibroblast growth factor 21 (FGF21 that activates various functions of BAT including thermogenesis. Thus, the enhancement of lipid metabolism and FGF21 may contribute to the cold resistance of Pgam5-deficient mice under fasting condition. Finally, we also found that Pgam5-deficient mice are resistant to high-fat-diet-induced obesity. Our study uncovered that PGAM5 is involved in the whole-body metabolism in response to stresses that impose metabolic challenges on mitochondria.

  7. The Ablation of Mitochondrial Protein Phosphatase Pgam5 Confers Resistance Against Metabolic Stress.

    Sekine, Shiori; Yao, Akari; Hattori, Kazuki; Sugawara, Sho; Naguro, Isao; Koike, Masato; Uchiyama, Yasuo; Takeda, Kohsuke; Ichijo, Hidenori

    2016-03-01

    Phosphoglycerate mutase family member 5 (PGAM5) is a mitochondrial protein phosphatase that has been reported to be involved in various stress responses from mitochondrial quality control to cell death. However, its roles in vivo are largely unknown. Here, we show that Pgam5-deficient mice are resistant to several metabolic insults. Under cold stress combined with fasting, Pgam5-deficient mice better maintained body temperature than wild-type mice and showed an extended survival rate. Serum triglycerides and lipid content in brown adipose tissue (BAT), a center of adaptive thermogenesis, were severely reduced in Pgam5-deficient mice. Moreover, although Pgam5 deficiency failed to maintain proper mitochondrial integrity in BAT, it reciprocally resulted in the dramatic induction of fibroblast growth factor 21 (FGF21) that activates various functions of BAT including thermogenesis. Thus, the enhancement of lipid metabolism and FGF21 may contribute to the cold resistance of Pgam5-deficient mice under fasting condition. Finally, we also found that Pgam5-deficient mice are resistant to high-fat-diet-induced obesity. Our study uncovered that PGAM5 is involved in the whole-body metabolism in response to stresses that impose metabolic challenges on mitochondria. PMID:27077115

  8. Cell wall dynamics modulate acetic acid-induced apoptotic cell death of Saccharomyces cerevisiae

    António Rego

    2014-08-01

    Full Text Available Acetic acid triggers apoptotic cell death in Saccharomyces cerevisiae, similar to mammalian apoptosis. To uncover novel regulators of this process, we analyzed whether impairing MAPK signaling affected acetic acid-induced apoptosis and found the mating-pheromone response and, especially, the cell wall integrity pathways were the major mediators, especially the latter, which we characterized further. Screening downstream effectors of this pathway, namely targets of the transcription factor Rlm1p, highlighted decreased cell wall remodeling as particularly important for acetic acid resistance. Modulation of cell surface dynamics therefore emerges as a powerful strategy to increase acetic acid resistance, with potential application in industrial fermentations using yeast, and in biomedicine to exploit the higher sensitivity of colorectal carcinoma cells to apoptosis induced by acetate produced by intestinal propionibacteria.

  9. Effect of stress and strain on corrosion resistance of duplex stainless steel

    The interplay of the mechanical and electrochemical phenomena has been a subject of active research. In this paper, corrosion resistance studies about SAF2205 and SAF2507 duplex stainless steel were carried out under elastic stress applied (100 MPa, 300 MPa, 500 MPa) and pre-strain (5%, 10%, 15%) in 3.5% NaCl and 2 mol/L HCl solution. Potentiodynamic anodic polarization study revealed that corrosion resistance of SAF2205 duplex stainless steel decreases slightly with increasing of elastic stress level and noticeably with increasing of pre-strained level. Scanning electron microscopy investigation on surface of the electrochemical tested SAF2205 duplex stainless steel samples indicated that pitting is always located in austenite grains when pre-strain level is below 5% (including different elastic stress level) and located on intersection of ferrite and austenite grain when pre-strain level is above 5%. For SAF2507 duplex stainless steel, elastic stress and pre-strain have no effect on general corrosion and pitting corrosion. Based on deformation mechanism of duplex structure and the relationship of mechanical load and corrosion potential, Pitting corrosion behavior of duplex stainless steel is explained and discussed

  10. Monascus-fermented dioscorea enhances oxidative stress resistance via DAF-16/FOXO in Caenorhabditis elegans.

    Yeu-Ching Shi

    Full Text Available BACKGROUND: Monascus-fermented products are mentioned in an ancient Chinese pharmacopoeia of medicinal food and herbs. Monascus-fermented products offer valuable therapeutic benefits and have been extensively used in East Asia for several centuries. Several biological activities of Monascus-fermented products were recently described, and the extract of Monascus-fermented products showed strong antioxidant activity of scavenging DPPH radicals. To evaluate whether Monascus-fermented dioscorea products have potential as nutritional supplements, Monascus-fermented dioscorea's modulation of oxidative-stress resistance and associated regulatory mechanisms in Caenorhabditis elegans were investigated. PRINCIPAL FINDINGS: We examined oxidative stress resistance of the ethanol extract of red mold dioscorea (RMDE in C. elegans, and found that RMDE-treated wild-type C. elegans showed an increased survival during juglone-induced oxidative stress compared to untreated controls, whereas the antioxidant phenotype was absent from a daf-16 mutant. In addition, the RMDE reduced the level of intracellular reactive oxygen species in C. elegans. Finally, the RMDE affected the subcellular distribution of the FOXO transcription factor, DAF-16, in C. elegans and induced the expression of the sod-3 antioxidative gene. CONCLUSIONS: These findings suggest that the RMDE acts as an antioxidative stress agent and thus may have potential as a nutritional supplement. Further studies in C. elegans suggest that the antioxidant effect of RMDE is mediated via regulation of the DAF-16/FOXO-dependent pathway.

  11. Calculation of Local Stress and Fatigue Resistance due to Thermal Stratification on Pressurized Surge Line Pipe

    Thermal stratification introduces thermal shock effect which results in local stress and fatigue problems that must be considered in the design of nuclear power plant components. Local stress and fatigue calculation were performed on the Pressurize Surge Line piping system of the Pressurize Water Reactor of the Nuclear Power Plant. Analysis was done on the operating temperature between 177 to 343 deg. C and the operating pressure of 16 MPa (160 Bar). The stagnant and transient condition with two kinds of stratification model has been evaluated by the two dimensional finite elements method using the ANSYS program. Evaluation of fatigue resistance is developed based on the maximum local stress using the ASME standard Code formula. Maximum stress of 427 MPa occurred at the upper side of the top half of hot fluid pipe stratification model in the transient case condition. The evaluation of the fatigue resistance is performed on 500 operating cycles in the life time of 40 years and giving the usage value of 0,64 which met to the design requirement for class 1 of nuclear component. The out surge transient were the most significant case in the localized effects due to thermal stratification.

  12. Influence of neighboring plants on shading stress resistance and recovery of eelgrass, Zostera marina L.

    Camilla Gustafsson

    Full Text Available Stressful environments may enhance the occurrence of facilitative interspecific interactions between plants. In several regions, Zostera marina occurs in mixed assemblages. However, the potential effects of plant diversity on stress responses and stability properties of Z. marina are poorly understood. We investigated the resistance and recovery of Z. marina subjected to shading (1 mo in a field experiment lasting 2.5 mo. We shaded Z. marina planted in mono- and polycultures (Potamogeton perfoliatus, P. pectinatus, P. filiformis in a factorial design (Shading×Richness at 2 m depth. We estimated the resistance and recovery of Z. marina by measuring four response variables. Polyculture Z. marina lost proportionally less biomass than monocultures, thus having a greater resistance to shading. In contrast, after a 1 mo recovery period, monocultures exhibited higher biomass gain, and a faster recovery than polycultures. Our results suggest that plant species richness enhances the resistance of Z. marina through facilitative mechanisms, while the faster recovery in monocultures is possibly due to interspecific competition. Our results highlight the need of a much better understanding of the effects of interspecific interactions on ecosystem processes in mixed seagrass meadows, and the preservation of diverse plant assemblages to maintain ecosystem functioning.

  13. [Stress-resistance and the condition of surfactant system and water balance in the lung of suspended rats].

    Bryndina, I G; Vasilieva, N N; Baranov, V M

    2013-01-01

    White male rats with the body mass of 180-220 grams were distributed into the open-field active (presumably stress-resistant) and open-field inactive (presumably stress vulnerable) groups for a 10-day experimental suspension with the purpose to evaluate the surfactant activity in bronchoalveolar lavages, total phospholipids and their fractions, and water balance in the lung. In modeled microgravity, augmented blood filling of the rat's lung increases the alveolar phospholipid content and alters the phospholipid fractional composition in the pulmonary surfactant. Ten-day suspension raises pulmonary surfactant activity to a greater extent in stress-resistant animals rather than in their stress vulnerable peers. PMID:24032163

  14. Overexpression of the dual-specificity phosphatase MKP-4/DUSP-9 protects against stress-induced insulin resistance

    Emanuelli, Brice; Eberlé, Delphine; Suzuki, Ryo;

    2008-01-01

    Insulin resistance, a hallmark of type 2 diabetes and obesity, is associated with increased activity of MAP and stress-activated protein (SAP) kinases, which results in decreased insulin signaling. Our goal was to investigate the role of MAP kinase phosphatase-4 (MKP-4) in modulating this process......, improved glucose intolerance, decreased expression of gluconeogenic and lipogenic genes, and reduced hepatic steatosis. Thus, MKP-4 has a protective effect against the development of insulin resistance through its ability to dephosphorylate and inactivate crucial mediators of stress-induced insulin...... resistance, such as ERK and JNK, and increasing MKP-4 activity might provide a therapy for insulin-resistant disorders....

  15. Effect of cold stress on broilers selected for resistance or susceptibility to ascites syndrome.

    Balog, J M; Kidd, B D; Huff, W E; Huff, G R; Rath, N C; Anthony, N B

    2003-09-01

    Genetic selection for an ascites-resistant line of broilers is seen as a permanent solution to the ascites problem. Ascites-resistant and ascites-susceptible lines have been developed using sire family selection based on mortality data taken from siblings reared in a hypobaric chamber (simulated 2,900 m above sea level). The relaxed line is representative of the original commercial pureline stock randomly mated with no artificial selection pressure. The objectives of this study were to evaluate the differences between the lines when reared in floor pens and subjected to an ascites-inducing cold stress. Seven hundred eighty three straight run broilers were reared in floor pens at local elevation (390 m above sea level). Feed and water were available ad libitum. Birds were brooded at 32 C during the first week. The second week birds were maintained at 30 degrees C. Cold stress was applied for the remaining 4 wk at 14 degrees C. Mortalities were necropsied daily to determine cause of death. Birds and feed were weighed weekly. At 6 wk, five birds per pen were bled, and half the survivors in each pen (8 to 15 birds) were killed, necropsied, and scored for ascites. Blood gases, clinical chemistries, and blood cell counts were taken. Liver, spleen, split heart, and lung weights were recorded. Body weights were not different among the resistant, susceptible, and relaxed lines (P Ascites incidence, as measured by mortality and lesion score at necropsy, was higher in the susceptible and relaxed lines when compared to the resistant line; 18.8, 12.7, and 1.6% respectively (P ascites-resistant line was growing as rapidly as the other lines and was as resistant to ascites as it had been under hypobaric conditions. PMID:12967249

  16. Enhancement of stress resistance of the guppy Poecilia reticulata through feeding with vitamin C supplement

    Lim, L C; Dhert, P.; Chew, W.Y.; Dermaux, V.; Nelis, H.; Sorgeloos, P.

    2002-01-01

    This study investigated the use of vitamin C supplement in formulated diets and live Artemia juveniles to enhance the stress resistance of the guppy Poecilia reticulata. To evaluate the stress resistance, fish were subjected to osmotic shock in pre-aerated water containing 35 ppt sodium chloride. Ascorbyl acid-poly phosphate and ascorbyl palmitate were used as vitamin C sources for formulated diets and live Artemia juveniles, respectively. Results showed that guppies fed moist formulated diet...

  17. THE TSC COMPLEX IS REQUIRED FOR THE BENEFITS OF DIETARY PROTEIN RESTRICTION ON STRESS RESISTANCE IN VIVO

    Eylul Harputlugil; Christopher Hine; Dorathy Vargas; Lauren Robertson; Brendan D. Manning; James R. Mitchell

    2014-01-01

    Protein restriction (PR) is important for the benefits of dietary restriction on longevity and stress resistance, but relevant nutrient sensors and downstream effectors in mammals remain poorly defined. We used PR-mediated protection from hepatic ischemia reperfusion injury to probe genetic requirements for the evolutionarily conserved nutrient sensors GCN2 and mTORC1 in stress resistance. One week of PR reduced free amino acids and circulating growth factors, activating GCN2 and mTORC1 repre...

  18. Hepatoprotective effect of vitamin C on lithocholic acid-induced cholestatic liver injury in Gulo(-/-) mice.

    Yu, Su Jong; Bae, Seyeon; Kang, Jae Seung; Yoon, Jung-Hwan; Cho, Eun Ju; Lee, Jeong-Hoon; Kim, Yoon Jun; Lee, Wang Jae; Kim, Chung Yong; Lee, Hyo-Suk

    2015-09-01

    Prevention and restoration of hepatic fibrosis from chronic liver injury is essential for the treatment of patients with chronic liver diseases. Vitamin C is known to have hepatoprotective effects, but their underlying mechanisms are unclear, especially those associated with hepatic fibrosis. Here, we analyzed the impact of vitamin C on bile acid induced hepatocyte apoptosis in vitro and lithocholic acid (LCA)-induced liver injury in vitamin C-insufficient Gulo(-/-) mice, which cannot synthesize vitamin C similarly to humans. When Huh-BAT cells were treated with bile acid, apoptosis was induced by endoplasmic reticulum stress-related JNK activation but vitamin C attenuated bile acid-induced hepatocyte apoptosis in vitro. In our in vivo experiments, LCA feeding increased plasma marker of cholestasis and resulted in more extensive liver damage and hepatic fibrosis by more prominent apoptotic cell death and recruiting more intrahepatic inflammatory CD11b(+) cells in the liver of vitamin C-insufficient Gulo(-/-) mice compared to wild type mice which have minimal hepatic fibrosis. However, when vitamin C was supplemented to vitamin C-insufficient Gulo(-/-) mice, hepatic fibrosis was significantly attenuated in the liver of vitamin C-sufficient Gulo(-/-) mice like in wild type mice and this hepatoprotective effect of vitamin C was thought to be associated with both decreased hepatic apoptosis and necrosis. These results suggested that vitamin C had hepatoprotective effect against cholestatic liver injury. PMID:26057690

  19. EXPRESSION OF BACTERIAL PROTEIN-A IN TOBACCO LEADS TO ENHANCED RESISTANCE TO STRESS CONDITIONS

    Chaitali Roy

    2014-08-01

    Full Text Available Tobacco is the most commonly used plant for expression of transgenes from a variety of organisms because it can be easily grown and transformed, it provides abundant amounts of fresh tissue and has a well-established cell culture system. As bacterial enzymes can be synthesized in tobacco, here we explore the possibility of in planta expression of staphylococcal protein-A(PA which is an antibody, an important group among biopharmaceuticals. In our study we have shown that the tobacco plants harboring PA gene could combat the crown gall infection and also effective in resisting abiotic stress conditions. Transgenic plants when subjected to interact with wild variety of Agrobacterium shows its enhanced capability to resist the gall formation. And when transgenic tobacco plants were grown in presence of 200mM NaCl and/or MG(Methylglyoxal solution, shows their increased tolerance towards salinity stress and high MG stress. So far transgenic tobacco plants are concerned, improvements in the expression of recombinant proteins and their recovery from tobacco may also enhance production and commercial use of this protein.

  20. Mechanical stress effect on the crystallization behavior of Ge2Sb2Te5 films studied by electrical resistance measurement

    The mechanical stress effect on the crystallization behaviour of Ge2Sb2Te5(GST) thin films is carefully investigated by electrical resistance measurements. It is found that the crystallization temperature of GST films increases as external compressive stress is applied, while the crystallization temperature decreases under tensile stress. We also find that the uneven distribution of extrinsic stress can widen the span of transition temperature. These results clearly demonstrate that mechanical stress plays an important role during the crystallization process of GST films and may further influence the reliability and storage speed of relevant devices. (copyright 2013 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  1. Variation in adult life history and stress resistance across five species of Drosophila

    N. Sharmila Bharathi; N. G. Prasad; Mallikarjun Shakarad; Amitabh Joshi

    2003-12-01

    species. In terms of overall performance, the laboratory population of D. melanogaster was clearly superior, under laboratory conditions, to the other four species if adult lifespan, lifetime fecundity, average daily fecundity, and absolute starvation and desiccation resistance are considered. This finding is contrary to several recent reports of substantially higher adult lifespan and stress resistance in recently wild-caught flies, relative to flies maintained for a long time in discrete-generation laboratory cultures. Possible explanations for these apparent anomalies are discussed in the context of the differing selection pressures likely to be experienced by Drosophila populations in laboratory versus wild environments.

  2. Torsional stress dependence of reactance and resistance in Fe-rich amorphous wires at low frequencies

    Amorphous ferromagnetic wire with a highly positive saturation magnetostriction coefficient, made of Fe73.5Si13.5B9Nb3Cu1, was simultaneously submitted to both, an AC current passing through it and a torsional stress, in order to induce a helical magnetic anisotropy in the wire that modifies its domain structure and therefore the magnetic response of the sample. The aim of this work is to study the reactive, resistive and impedance behaviour in this Fe-rich wire, submitted to different applied torsional stresses, and for several values of the AC current amplitude through the wire (5-20 mArms), in the low frequency range, f< MHz. The experimental results are explained on the basis of the core-shell model

  3. Acute exercise improves endothelial function despite increasing vascular resistance during stress in smokers and nonsmokers.

    Rooks, Cherie R; McCully, Kevin K; Dishman, Rod K

    2011-09-01

    The present study examined the effect of acute exercise on flow mediated dilation (FMD) and reactivity to neurovascular challenges among female smokers and nonsmokers. FMD was determined by arterial diameter, velocity, and blood flow measured by Doppler ultrasonography after forearm occlusion. Those measures and blood pressure and heart rate were also assessed in response to forehead cold and the Stroop Color-Word Conflict Test (CWT) before and after 30 min of rest or an acute bout of cycling exercise (∼50% VO₂ peak). Baseline FMD and stress responses were not different between smokers and nonsmokers. Compared to passive rest, exercise increased FMD and decreased arterial velocity and blood flow responses during the Stroop CWT and forehead cold in both groups. Overall, acute exercise improved endothelial function among smokers and nonsmokers despite increasing vascular resistance and reducing limb blood flow during neurovascular stress. PMID:21457274

  4. Resistance of LaCl3 to Oxidative Stress Induced by 2, 4-Dichlorophenoxy

    Jia Yanxia; Gao Yongsheng; Zeng Fuli

    2005-01-01

    Cucumber seedlings were sprayed with different concentrations of LaCl3 for 3 d continuously. After 7 d of this treatment, the plants were treated with 1200 mg·L-1 2,4-dichlorophennoxy(2,4-D) for 24 h. The leaves were harvested and rinsed with 5 mmol · L-1 EDTA. The concentrations of photosynthetic pigments, soluble protein and metabolites related to oxidative stress and the activities of antioxidant enzymes in leaves were assayed. The results show that the treatment with appropriate concentration of LaCl3 has resistant effect on oxidative stress induced by 2, 4-D. Proper concentration of LaCl3 promotes the activity of antioxidant system in plants and alleviates the damage caused by 2, 4-D.

  5. Contribution to surface physicochemical factors to stress corrosion resistance in stainless steels

    The author of this research thesis first presents and discusses the various aspects of stress corrosion cracking of Fe-Cr-Ni alloys of high purity: experimental conditions (alloy elaboration, sample preparation), corrosion results (Schaeffer diagram, crack morphology, intergranular corrosion), influence of addition elements in ferritic alloys. He reports an electrochemical study of stainless steels in magnesium chloride (experimental conditions, influence of metallurgic and environmental parameters on polarization resistance, current-voltage curves), and an analytical study of layers formed in the magnesium chloride

  6. Analysis of drought resistance HVA1 gene under drought stress in different Poa pratensis cultivars

    WU Yanhua; CHEN Yajun; SHEN Fengjuan; SUN Xiaoyan

    2007-01-01

    Total RNA from leaves of Poa pratensis cultivars under drought stress was extracted for reversing transcription to cDNA and then cDNA as template for PCR reaction by designing primer of cds of Hordeum valgare HVA1 drought resistance gene from GenBank. The amplified products were positive recon identified by using procedures of recovery, connection, transformation and enzyme separation. The length of cloned gene sequence was 324 bp, identity reached 79.27% with Barley HVA1 gene that meaned the cloned gene sequence was the partial HVA1 gene of Poa pratensis.

  7. Osmoregulation Mechanism of Drought Stress and Genetic Engineering Strategies for Improving Drought Resistance in Plants

    Du Jinyou; Chen Xiaoyang; Li Wei; Gao Qiong

    2004-01-01

    Drought, one of the main adverse environmental factors, obviously affected plant growth and development. Many adaptive strategies have been developed in plants for coping with drought or water stress, among which osmoregulation is one of the important factors of plant drought tolerance. Many substances play important roles in plant osmoregulation for drought resistance, including proline, glycine betaine, Lea proteins and soluble sugars such as levan, trehalose, sucrose, etc. The osmoregulation mechanism and the genetic engineering of plant drought-tolerance are reviewed in this paper.

  8. Modulation of cell metabolic pathways and oxidative stress signaling contribute to acquired melphalan resistance in multiple myeloma cells

    Zub, Kamila Anna; Sousa, Mirta Mittelstedt Leal de; Sarno, Antonio;

    2015-01-01

    of the AKR1C family involved in prostaglandin synthesis contribute to the resistant phenotype. Finally, selected metabolic and oxidative stress response enzymes were targeted by inhibitors, several of which displayed a selective cytotoxicity against the melphalan-resistant cells and should be further...... and pathways not previously associated with melphalan resistance in multiple myeloma cells, including a metabolic switch conforming to the Warburg effect (aerobic glycolysis), and an elevated oxidative stress response mediated by VEGF/IL8-signaling. In addition, up-regulated aldo-keto reductase levels...

  9. High amylose resistant starch diet ameliorates oxidative stress, inflammation, and progression of chronic kidney disease.

    Nosratola D Vaziri

    Full Text Available Inflammation is a major mediator of CKD progression and is partly driven by altered gut microbiome and intestinal barrier disruption, events which are caused by: urea influx in the intestine resulting in dominance of urease-possessing bacteria; disruption of epithelial barrier by urea-derived ammonia leading to endotoxemia and bacterial translocation; and restriction of potassium-rich fruits and vegetables which are common sources of fermentable fiber. Restriction of these foods leads to depletion of bacteria that convert indigestible carbohydrates to short chain fatty acids which are important nutrients for colonocytes and regulatory T lymphocytes. We hypothesized that a high resistant starch diet attenuates CKD progression. Male Sprague Dawley rats were fed a chow containing 0.7% adenine for 2 weeks to induce CKD. Rats were then fed diets supplemented with amylopectin (low-fiber control or high fermentable fiber (amylose maize resistant starch, HAM-RS2 for 3 weeks. CKD rats consuming low fiber diet exhibited reduced creatinine clearance, interstitial fibrosis, inflammation, tubular damage, activation of NFkB, upregulation of pro-inflammatory, pro-oxidant, and pro-fibrotic molecules; impaired Nrf2 activity, down-regulation of antioxidant enzymes, and disruption of colonic epithelial tight junction. The high resistant starch diet significantly attenuated these abnormalities. Thus high resistant starch diet retards CKD progression and attenuates oxidative stress and inflammation in rats. Future studies are needed to explore the impact of HAM-RS2 in CKD patients.

  10. Histone Modifications in Senescence-Associated Resistance to Apoptosis by Oxidative Stress

    Yan Y. Sanders

    2013-01-01

    Full Text Available Aging and age-related diseases are associated with cellular senescence that results in variable apoptosis susceptibility to oxidative stress. Although fibroblast senescence has been associated with apoptosis resistance, mechanisms for this have not been well defined. In this report, we studied epigenetic mechanisms involving histone modifications that confer apoptosis resistance to senescent human diploid fibroblasts (HDFs. HDFs that undergo replicative senescence display typical morphological features, express senescence-associated β-galactosidase, and increased levels of the tumor suppressor genes, p16, p21, and caveolin-1. Senescent HDFs are more resistant to oxidative stress (exogenous H2O2-induced apoptosis in comparison to non-senescent (control HDFs; this is associated with constitutively high levels of the anti-apoptotic gene, Bcl-2, and low expression of the pro-apoptotic gene, Bax. Cellular senescence is characterized by global increases in H4K20 trimethylation and decreases in H4K16 acetylation in association with increased activity of Suv420h2 histone methyltransferase (which targets H4K20, decreased activity of the histone acetyltransferase, Mof (which targets H4K16, as well as decreased total histone acetyltransferase activity. In contrast to Bax gene, chromatin immunoprecipitation studies demonstrate marked enrichment of the Bcl-2 gene with H4K16Ac, and depletion with H4K20Me3, predicting active transcription of this gene in senescent HDFs. These data indicate that both global and locus-specific histone modifications of chromatin regulate altered Bcl-2:Bax gene expression in senescent fibroblasts, contributing to its apoptosis-resistant phenotype.

  11. Glucocorticoid Fast Feedback Inhibition of Stress-Induced ACTH Secretion in the Male Rat: Rate Independence and Stress-State Resistance.

    Osterlund, Chad D; Rodriguez-Santiago, Mariana; Woodruff, Elizabeth R; Newsom, Ryan J; Chadayammuri, Anjali P; Spencer, Robert L

    2016-07-01

    Normal glucocorticoid secretion is critical for physiological and mental health. Glucocorticoid secretion is dynamically regulated by glucocorticoid-negative feedback; however, the mechanisms of that feedback process are poorly understood. We assessed the temporal characteristics of glucocorticoid-negative feedback in vivo using a procedure for drug infusions and serial blood collection in unanesthetized rats that produced a minimal disruption of basal ACTH plasma levels. We compared the negative feedback effectiveness present when stress onset coincides with corticosterone's (CORT) rapidly rising phase (30 sec pretreatment), high plateau phase (15 min pretreatment), or restored basal phase (60 min pretreatment) as well as effectiveness when CORT infusion occurs after the onset of stress (5 min poststress onset). CORT treatment prior to stress onset acted remarkably fast (within 30 sec) to suppress stress-induced ACTH secretion. Furthermore, fast feedback induction did not require rapid increases in CORT at the time of stress onset (hormone rate independent), and those feedback actions were relatively long lasting (≥15 min). In contrast, CORT elevation after stress onset produced limited and delayed ACTH suppression (stress state resistance). There was a parallel stress-state resistance for CORT inhibition of stress-induced Crh heteronuclear RNA in the paraventricular nucleus but not Pomc heteronuclear RNA in the anterior pituitary. CORT treatment did not suppress stress-induced prolactin secretion, suggesting that CORT feedback is restricted to the control of hypothalamic-pituitary-adrenal axis elements of a stress response. These temporal, stress-state, and system-level features of in vivo CORT feedback provide an important physiological context for ex vivo studies of molecular and cellular mechanisms of CORT-negative feedback. PMID:27145013

  12. Acid-induced changes of brain protein buffering

    Kraig, Richard P.; Wagner, Robert J.

    1987-01-01

    Excessive cellular acidosis is thought to enhance destruction of brain from ischemia. Protein denaturation may contribute to such injury although the behavior of brain proteins to acidosis is poorly defined. As a first approach to detect acid-induced changes in brain proteins and to characterize buffer content, homogenates were acidified for 20 min (as low as pH 3.1), returned to baseline pH (6.9), and then titrated. Titration curves show a significant (P < 0.0001) and permanent increase in b...

  13. Biosynthesis of vitamin C by yeast leads to increased stress resistance.

    Paola Branduardi

    Full Text Available BACKGROUND: In industrial large scale bio-reactions micro-organisms are generally exposed to a variety of environmental stresses, which might be detrimental for growth and productivity. Reactive oxygen species (ROS play a key role among the common stress factors--directly--through incomplete reduction of O(2 during respiration, or indirectly--caused by other stressing factors. Vitamin C or L-ascorbic acid acts as a scavenger of ROS, thereby potentially protecting cells from harmful oxidative products. While most eukaryotes synthesize ascorbic acid, yeast cells produce erythro-ascorbic acid instead. The actual importance of this antioxidant substance for the yeast is still a subject of scientific debate. METHODOLOGY/PRINCIPAL FINDINGS: We set out to enable Saccharomyces cerevisiae cells to produce ascorbic acid intracellularly to protect the cells from detrimental effects of environmental stresses. We report for the first time the biosynthesis of L-ascorbic acid from D-glucose by metabolically engineered yeast cells. The amount of L-ascorbic acid produced leads to an improved robustness of the recombinant cells when they are subjected to stress conditions as often met during industrial fermentations. Not only resistance against oxidative agents as H(2O(2 is increased, but also the tolerance to low pH and weak organic acids at low pH is increased. CONCLUSIONS/SIGNIFICANCE: This platform provides a new tool whose commercial applications may have a substantial impact on bio-industrial production of Vitamin C. Furthermore, we propose S. cerevisiae cells endogenously producing vitamin C as a cellular model to study the genesis/protection of ROS as well as genotoxicity.

  14. Multiple roles of putrescine and spermidine in stress resistance and virulence of Salmonella enterica serovar Typhimurium.

    Espinel, Irene Cartas; Guerra, Priscila Regina; Jelsbak, Lotte

    2016-06-01

    Polyamines (putrescine and spermidine) are small-cationic amines ubiquitous in nature and present in most living cells. In recent years they have been linked to virulence of several human pathogens including Shigella spp and Salmonella enterica serovar Typhimurium (S. Typhimurium). Central to S. Typhimurium virulence is the ability to survive and replicate inside macrophages and resisting the antimicrobial attacks in the form of oxidative and nitrosative stress elicited from these cells. In the present study, we have investigated the role of polyamines in intracellular survival and systemic infections of mice. Using a S. Typhimurium mutant defective for putrescine and spermidine biosynthesis, we show that polyamines are essential for coping with reactive nitrogen species, possibly linking polyamines to increased intracellular stress resistance. However, using a mouse model defective for nitric oxide production, we find that polyamines are required for systemic infections independently of host-produced reactive nitrogen species. To distinguish between the physiological roles of putrescine and spermidine, we constructed a strain deficient for spermidine biosynthesis and uptake, but with retained ability to produce and import putrescine. Interestingly, in this mutant we observe a strong attenuation of virulence during infection of mice proficient and deficient for nitric oxide production suggesting that spermidine, specifically, is essential for virulence of S. Typhimurium. PMID:27041598

  15. IbeR facilitates stress-resistance, invasion and pathogenicity of avian pathogenic Escherichia coli.

    Shaohui Wang

    Full Text Available Systemic infections by avian pathogenic Escherichia coli (APEC are economically devastating to poultry industries worldwide. IbeR, located on genomic island GimA, was shown to serve as an RpoS-like regulator in rpoS gene mutation neonatal meningitis E. coli (NMEC RS218. However, the role of IbeR in pathogenicity of APEC carrying active RpoS has not yet been investigated. We showed that the APEC IbeR could elicit antibodies in infected ducks, suggesting that IbeR might be involved in APEC pathogenicity. To investigate the function of IbeR in APEC pathogenesis, mutant and complementation strains were constructed and characterized. Inactivation of ibeR led to attenuated virulence and reduced invasion capacity towards DF-1 cells, brains and cerebrospinal fluid (CSF in vitro and in vivo. Bactericidal assays demonstrated that the mutant strain had impaired resistance to environmental stress and specific pathogen-free (SPF chicken serum. These virulence-related phenotypes were restored by genetic complementation. Quantitative real-time reverse transcription PCR revealed that IbeR controlled expression of stress-resistance genes and virulence genes, which might led to the associated virulence phenotype.

  16. Development of Modified 304 Stainless Steel Resistant to Stress Corrosion Cracking in Chloride Environment

    2002-01-01

    This was a feasibility study for a modified 304 steel resistant to stress corrosion cracking (SCC) in aqueous environment containing chloride. SCC tests were conducted potentiostaticaly with spot-welded specimens, which had both crevice and residual stress, mainly in 3 % NaCl solution at various temperatures to determine the critical temperature for SCC at and below which the steel would not suffer from SCC. The effects of individual alloying element of silicon, manganese and copper on SCC of 18Cr-14Ni steels which phosphor content is 0.002 % and molybdenum content is 0.01 % were examined. Addition of 1 or 2 % of copper has beneficial effect on resistance to SCC, while increasing silicon or manganese content has no significant effect. Critical temperature of the steel with 0.002 % of phosphor and 2 % of copper is 150 ℃, which is markedly higher than 50 ℃ of 304L steel. However, the beneficial effect of copper is reduced with increasing phosphor content. From practical viewpoint, the modified steel with good SCC resistance should have 0.01 %-0.015 % of phosphor and 0.3 % or more of molybdenum, because it is very difficult to reduce phosphor content below 0.008 % industrially and such molybdenum content is inevitably introduced through cost-saving melting process using return steel. Aluminium is to be added as another alloying element and 3 % of aluminium combined with 2 % of copper has been found to negate the deleterious effects of increased phosphor and molybdenum content. As a candidate steel at this stage, 14Cr-16Ni-0.013P-2Cu-1Al-(0.3-1)Mo steel has critical temperature of 110 ℃.

  17. Numerical design and optimization of hydraulic resistance and wall shear stress inside pressure-driven microfluidic networks.

    Damiri, Hazem Salim; Bardaweel, Hamzeh Khalid

    2015-11-01

    Microfluidic networks represent the milestone of microfluidic devices. Recent advancements in microfluidic technologies mandate complex designs where both hydraulic resistance and pressure drop across the microfluidic network are minimized, while wall shear stress is precisely mapped throughout the network. In this work, a combination of theoretical and modeling techniques is used to construct a microfluidic network that operates under minimum hydraulic resistance and minimum pressure drop while constraining wall shear stress throughout the network. The results show that in order to minimize the hydraulic resistance and pressure drop throughout the network while maintaining constant wall shear stress throughout the network, geometric and shape conditions related to the compactness and aspect ratio of the parent and daughter branches must be followed. Also, results suggest that while a "local" minimum hydraulic resistance can be achieved for a geometry with an arbitrary aspect ratio, a "global" minimum hydraulic resistance occurs only when the aspect ratio of that geometry is set to unity. Thus, it is concluded that square and equilateral triangular cross-sectional area microfluidic networks have the least resistance compared to all rectangular and isosceles triangular cross-sectional microfluidic networks, respectively. Precise control over wall shear stress through the bifurcations of the microfluidic network is demonstrated in this work. Three multi-generation microfluidic network designs are considered. In these three designs, wall shear stress in the microfluidic network is successfully kept constant, increased in the daughter-branch direction, or decreased in the daughter-branch direction, respectively. For the multi-generation microfluidic network with constant wall shear stress, the design guidelines presented in this work result in identical profiles of wall shear stresses not only within a single generation but also through all the generations of the

  18. In vitro selection for stress-resistant mutants and survey on offspring characteristics of peanut

    Previous studies in our lab had established high frequency of plant regeneration system via somatic embryogenesis and determination of the optimum mutation concentration of pingyangmycin (PYM), in vitro mutagenesis and directed screening for stress-resistant mutants of peanut were carried out in this study. The embryonic leaflets of peanut cv. Huayu 20 were cultured on induction medium supplemented with 3 mg/L PYM for 4 weeks to induce mutation. Hydroxyproline (HYP) was added to medium to provide selection pressure; the concentration was 4 mg/L for somatic embryo germination and 8 mg/L for plantlet formation. Regenerated mutant plants were transplanted to the field after graft and acclimation, 13 of them produced pods. The seeds of these 13 strains were sown in the field, 12 out of them exhibited different plant type compared with their wild type parent during seedling stage and growth stages, and most of them showed remarkable segregation of characters. The rest seeds from 7 of 13 strains mentioned above were sown in the green house, and were treated with drought stress. Most of the plants grew normally, while the wild type parent showed growth retardation. POD and SOD activity were determined using leaves subjected to drought stress as material. The results showed that the SOD values of 5 out of 7 lines were higher than that of the parent; the POD values of these lines also higher than that of the parent expect No.42. (authors)

  19. Performance and stress resistance of Nile tilapias fed different crude protein levels

    Ronald Kennedy Luz

    2012-02-01

    Full Text Available The objective of this study was to evaluate the effect of different levels of diet crude protein on the performance and stress resistance rate (Re of Oreochromis niloticus larvae and fingerlings. In the first experiment, 5, 15 and 25 day-old animals were submitted to 1, 5, 7, 10, 15, 20, 30 and 40 minutes of air exposure on a sieve. In the second experiment, tilapia larvae were fed with 32, 40 and 55% crude protein (CP diets. Animals after 15 and 30 days of feeding (21 and 36 days of life, respectively were submitted to the air exposure test for 7 and 10 minutes. Re was estimated based on survival 24 hours after the tests. In the first experiment, it was observed that 5-day-old animals were more resistant than animals with 10 and 20 days of feeding (15 and 25 days of life, respectively, when Re starts to decrease for longer than 7 minutes. In the second experiment, the different diets affected survival, performance and Re, and, in general, the worst results observed were the ones for the animals which received the 55% CP diet. The air exposure tests were efficient to evaluate the effect of diet on the resistance rate of Nile tilapia.

  20. The influence of pretreatment with ghrelin on the development of acetic-acid-induced colitis in rats.

    Maduzia, D; Matuszyk, A; Ceranowicz, D; Warzecha, Z; Ceranowicz, P; Fyderek, K; Galazka, K; Dembinski, A

    2015-12-01

    Ghrelin has been primarily shown to exhibit protective and therapeutic effect in the gut. Pretreatment with ghrelin inhibits the development of acute pancreatitis and accelerates pancreatic recovery in the course of this disease. In the stomach, ghrelin reduces gastric mucosal damage induced by ethanol, stress or alendronate, as well as accelerates the healing of acetic acid-induced gastric and duodenal ulcer. The aim of present studies was to investigate the effect of pretreatment with ghrelin on the development of acetic acid-induced colitis. Studies have been performed on male Wistar rats. Animals were treated intraperitoneally with saline (control) or ghrelin (4, 8 or 16 nmol/kg/dose). Saline or ghrelin was given twice: 8 and 1 h before induction of colitis. Colitis was induced by a rectal enema with 1 ml of 4% solution of acetic acid and the severity of colitis was assessed 1 or 24 hours after induction of inflammation. Rectal administration of acetic acid induced colitis in all animals. Damage of colonic wall was seen at the macroscopic and microscopic level. This effect was accompanied by a reduction in colonic blood flow and mucosal DNA synthesis. Moreover, induction of colitis significantly increased mucosal concentration of pro-inflammatory interleukin-1β (IL-1β), activity of myeloperoxidase and concentration of malondialdehyde (MDA). Mucosal activity of superoxide dismutase (SOD) was reduced. Pretreatment with ghrelin reduced the area and grade of mucosal damage. This effect was accompanied by an improvement of blood flow, DNA synthesis and SOD activity in colonic mucosa. Moreover, ghrelin administration reduced mucosal concentration of IL-1β and MDA, as well as decreased mucosal activity of myeloperoxidase. Administration of ghrelin protects the large bowel against the development of the acetic acid-induced colitis and this effect seems to be related to the ghrelin-evoked anti-inflammatory and anti-oxidative effects. PMID:26769837

  1. Nisin resistance of Listeria monocytogenes is increased by exposure to salt stress and is mediated via LiaR.

    Bergholz, Teresa M; Tang, Silin; Wiedmann, Martin; Boor, Kathryn J

    2013-09-01

    Growth of Listeria monocytogenes on refrigerated, ready-to-eat food is a significant food safety concern. Natural antimicrobials, such as nisin, can be used to control this pathogen on food, but little is known about how other food-related stresses may impact how the pathogen responds to these compounds. Prior work demonstrated that exposure of L. monocytogenes to salt stress at 7°C led to increased expression of genes involved in nisin resistance, including the response regulator liaR. We hypothesized that exposure to salt stress would increase subsequent resistance to nisin and that LiaR would contribute to increased nisin resistance. Isogenic deletion mutations in liaR were constructed in 7 strains of L. monocytogenes, and strains were exposed to 6% NaCl in brain heart infusion broth and then tested for resistance to nisin (2 mg/ml Nisaplin) at 7°C. For the wild-type strains, exposure to salt significantly increased subsequent nisin resistance (P salt-induced nisin resistance of wild-type strains, ΔliaR strains were significantly more sensitive to nisin (P monocytogenes against subsequent inactivation by nisin. Transcript levels of LiaR-regulated genes were induced by salt stress, and lmo1746 and telA were found to contribute to LiaR-mediated salt-induced nisin resistance. These data suggest that environmental stresses similar to those on foods can influence the resistance of L. monocytogenes to antimicrobials such as nisin, and potential cross-protective effects should be considered when selecting and applying control measures for this pathogen on ready-to-eat foods. PMID:23851083

  2. Selection for increased desiccation resistance in Drosophila melanogaster: Additive genetic control and correlated responses for other stresses

    Previously we found that Drosophila melanogaster lines selected for increased desiccation resistance have lowered metabolic rate and behavioral activity levels, and show correlated responses for resistance to starvation and a toxic ethanol level. These results were consistent with a prediction that increased resistance to many environmental stresses may be genetically correlated because of a reduction in metabolic energy expenditure. Here we present experiments on the genetic basis of the selection response and extend the study of correlated responses to other stresses. The response to selection was not sex-specific and involved X-linked and autosomal genes acting additively. Activity differences contributed little to differences in desiccation resistance between selected and control lines. Selected lines had lower metabolic rates than controls in darkness when activity was inhibited. Adults from selected lines showed increased resistance to a heat shock, 60Co-gamma-radiation, and acute ethanol and acetic acid stress. The desiccation, ethanol and starvation resistance of isofemale lines set up from the F2s of a cross between one of the selected and one of the control lines were correlated. Selected and control lines did not differ in ether-extractable lipid content or in resistance to acetone, ether or a cold shock

  3. Proteomic investigation of the ventral rat hippocampus links DRP-2 to escitalopram treatment resistance and SNAP to stress resilience in the chronic mild stress model of depression

    Bisgaard, Christina; Jayatissa, Magdalena N; Enghild, Jan J;

    2007-01-01

    The development of depression as well as recovery from depression is most likely accompanied by a change in protein expression profiles. The purpose of the present study was to quantitatively investigate global protein expression differences independent of any hypothesis describing depression...... etiology and recovery. Thus two-dimensional differential in-gel electrophoresis was employed to compare the ventral hippocampal proteomes between different treatment groups in the chronic mild stress (CMS) model of depression. The CMS paradigm induces anhedonic behaviour, which is a major symptom of...... (n = 12), CMS escitalopram responders (n = 11), CMS escitalopram non-responders (n = 13) and CMS resilient (stress resistant) (n = 12). Protein levels in the ventral rat hippocampus were compared between the groups to provide putative markers of anhedonia, escitalopram resistance, and stress...

  4. Stress-induced transformation in a Ni-Mn-In alloy and the concomitant change of resistivity

    Kokorin V.V.

    2015-01-01

    Full Text Available In this work, the influence of mechanical stress on magnetic properties and electric resistance of a Ni-Mn-In alloy was studied. It is shown that compression of Ni-Mn-In polycrystalline specimens brings about a stressinduced martensitic transformation. Optical images recorded in-situ confirmed the formation of a martensitic structure during loading and back-transformation upon unloading. Unloading after deformation of specimens that had experienced compressive strains up to 6% resulted in full recovery of their resistivity and magnetic susceptibility. The sharp increase in the electric resistance caused by the stress-induced transformation opens up new possibilities for Ni-Mn-In alloys to be used as a material for sensors responding to mechanical stress.

  5. Ecologically relevant stress resistance: from microarrays and quantitative trait loci to candidate genes – A research plan and preliminary results using Drosophila as a model organism and climatic and genetic stress as model stresses

    Volker Loeschcke; Jesper G Sørensen; Torsten N Kristensen

    2004-12-01

    We aim at studying adaptation to genetic and environmental stress and its evolutionary implications at different levels of biological organization. Stress influences cellular processes, individual physiology, genetic variation at the population level, and the process of natural selection. To investigate these highly connected levels of stress effects, it is advisable – if not critical – to integrate approaches from ecology, evolution, physiology, molecular biology and genetics. To investigate the mechanisms of stress resistance, how resistance evolves, and what factors contribute to and constrain its evolution, we use the well-defined model systems of Drosophila species, representing both cosmopolitan species such as D. melanogaster with a known genome map, and more specialized and ecologically well described species such as the cactophilic D. buzzatii. Various climate-related stresses are used as model stresses including desiccation, starvation, cold and heat. Genetic stress or genetic load is modelled by studying the consequences of inbreeding, the accumulation of (slightly) deleterious mutations, hybridization or the loss of genetic variability. We present here a research plan and preliminary results combining various approaches: molecular techniques such as microarrays, quantitative trait loci (QTL) analyses, quantitative PCR, ELISA or Western blotting are combined with population studies of resistance to climatic and genetic stress in natural populations collected across climatic gradients as well as in selection lines maintained in the laboratory.

  6. Prenatal SSRI alters the hormonal and behavioral responses to stress in female mice: Possible role for glucocorticoid resistance.

    Avitsur, Ronit; Grinshpahet, Rachel; Goren, Naama; Weinstein, Ido; Kirshenboim, Or; Chlebowski, Noa

    2016-08-01

    Life time prevalence of major depression disorder (MDD) is higher in women compared to men especially during the period surrounding childbirth. Women suffering from MDD during pregnancy use antidepressant medications, particularly Selective Serotonin Reuptake Inhibitors (SSRI). These drugs readily cross the placental barrier and impact the developing fetal brain. The present study assessed the effects of prenatal exposure to fluoxetine (FLX), an SSRI antidepressant drug, on corticosterone and behavioral responses to stress in female mice. In young females, prenatal FLX significantly elevated corticosterone response to continuous stress. In adults, prenatal FLX augmented corticosterone response to acute stress and suppressed the response to continuous stress. Additionally, prenatal FLX significantly augmented stress-induced increase in locomotion and reduced anxiety- and depressive-like behaviors in adult, but not young mice. The dexamethasone suppression test revealed that prenatal FLX induced a state of glucocorticoid resistance in adult females, indicating that the negative feedback control of the hypothalamic-pituitary-adrenal axis response to stress was disrupted. These findings provide the first indication of altered hormonal and behavioral responses to continuous stress and suggest a role for the development of glucocorticoid resistance in these effects. According to these findings, prenatal environment may have implications for stress sensitivity and responsiveness to life challenges. Furthermore, this study may assist in understanding the limitations and precautions that should be taken in the use of SSRIs during pregnancy. PMID:27283378

  7. Influence of Two Various Durations of Resistance Exercise on Oxidative Stress in the Male Rat’s Hearts

    Rafigheh Ghiasi; Mustafa Mohammadi; Javad Ashrafi Helan; Seied Razi Jafari Jozani; Shima Mohammadi; Akbar Ghiasi; Roya Naderi

    2015-01-01

    Introduction: The previous studies have suggested that alteration in oxidative stress and antioxidant defense depends on various factors, such as mode, intensity, frequency and duration of exercise. In this study, we compared the effects of two various durations of resistance exercise (1 month and 4 month) on oxidative stress and antioxidant status in cardiac tissue. Methods: Thirty Wistar male rats divided into 3 groups: control (sedentary), exercise-1 (regular exercise for 1 month) and exer...

  8. Loss of Oca2 disrupts the unfolded protein response and increases resistance to endoplasmic reticulum stress in melanocytes

    Cheng, Tsing; Orlow, Seth J.; Manga, Prashiela

    2013-01-01

    Accumulation of proteins in the endoplasmic reticulum (ER) typically induces stress and initiates the unfolded protein response (UPR) to facilitate recovery. If homeostasis is not restored, apoptosis is induced. However, adaptation to chronic UPR activation can increase resistance to subsequent acute ER stress. We therefore investigated adaptive mechanisms in Oculocutaneous albinism type 2 (Oca2)-null melanocytes where UPR signaling is arrested despite continued tyrosinase accumulation leadin...

  9. Bacteria associated with highly drought resistant Pistacia terebinthus: the key to reduce drought stress in other plant species?

    Van de Weyer, Inge

    2013-01-01

    Plant-associated bacteria can not only stimulate plant growth, but also play an important role in the adaptation of their host plant to stress-inducing environmental conditions such as extreme drought. In this project, the effect of inoculation with selected endophytic bacteria isolated from the highly drought resistant tree Pistacia terebinthus on the drought resistance of four different plant species was evaluated. The results show that drought had a strong negative impact on all plant spec...

  10. Withanolide A offers neuroprotection, ameliorates stress resistance and prolongs the life expectancy of Caenorhabditis elegans.

    Akhoon, Bashir Akhlaq; Pandey, Swapnil; Tiwari, Sudeep; Pandey, Rakesh

    2016-06-01

    Withanolide A (steroidal lactone) forms the major constituent of the most popular herbal drug in Ayurvedic medicine, Ashwagandha. It has been used since ancient times as an alternative medicine for the treatment of a variety of age related disorders. Here we provide multiple lines of evidence indicating that Withanolide A improves healthspan, delays age-associated physiological changes and also extends the lifespan of Caenorhabditis elegans. We also report several neuroprotective benefits of this natural product, including its anti-amyloidogenic effects, alleviation of α-synuclein aggregation and neuroprotection through modulation of neural mediators like acetylcholine. We observed that Withanolide A mediates lifespan extension and promotes stress resistance via insulin/insulin-like growth factor signaling pathway. Such findings could be helpful to develop a therapeutic medicine from this natural product for the prevention or reversal of age-related ailments and to improve the survival of patients suffering from Alzheimer's or Parkinson's disease. PMID:26956478

  11. Mechanical properties and environmental stress cracking resistance of rubber toughened polyester/kenaf composite

    2010-02-01

    Full Text Available In this study rubber-toughened polyester-kenaf fibre composites were prepared by adding various percentages of kenaf fibre in unsaturated polyester resin and subsequently cross linked using a mixture of organic peroxide methyl ethyl ketone and cobalt octanoate. Three percent (3% of liquid natural rubber (LNR were added as a toughening agent. The mechanical properties of the composites were evaluated by impact and flexural testing. Environmental stress cracking resistance (ESCR of polyester-kenaf composite in acid and base medium was also studied. It was found that the addition of LNR increased impact strength by about 66% and flexural strength by 70%. Measurement of ESCR shows that the composite has the fastest diffusion rate in acid medium, followed by that in base medium and then without medium. Bonding mechanisms were assessed by scanning electron microscope and FTIR analysis.

  12. Life at the Limits: Capacities of Isolated and Cultured Lichen Symbionts to Resist Extreme Environmental Stresses

    de Vera, J.-P.; Rettberg, P.; Ott, S.

    2008-10-01

    Lichens are described as a symbiosis formed by a myco- and photobiont, capable of colonizing habitats where their separate symbionts would not be able to survive. Space simulation studies on the separated symbionts of the lichen Xanthoria elegans have been performed to test their capacity to resist the most extreme conditions. The isolated cultured symbiont cells were exposed to different doses of the UV spectrum, and to vacuum. Cultures of both symbionts were analysed by specific vitality tests (LIVE/DEAD-staining detected by Confocal Laser Scanning Microscopy). Growth capacity of symbiont cultures on different media was analysed after exposure to extreme environmental stresses. The data obtained support the hypothesis that the symbiotic state considerably enhances the ability of the respective symbionts to survive exposure to extreme conditions, including the conditions of space simulation. Species such as X. elegans may, therefore, be suitable for use as model organisms in exobiological studies.

  13. The resistance of pure copper to stress corrosion cracking in repository environments

    The risk for stress corrosion cracking (SCC) of the copper canister in the final repository for high-level radioactive waste in Sweden is low. However, it is a desire to try to elucidate and if possible quantify this minor risk. Available information from others and own work is discussed together with possible methods to estimate the resistance of pure copper to SCC in repository environments. An attempt to rationalise available crack growth rate data is made. Electrochemically controlled slow strain rate testing of pure copper was performed in a sodium nitrite solution, known to give SCC, and in a synthetic groundwater of pH 9. For reasons of comparison, testing was also performed in air. Whereas the occurrence of SCC as expected was clear in the sodium nitrite solution, it cannot be claimed that SCC has occurred in the synthetic groundwater

  14. Resistance and Stress Finite Element Analysis of Different Types of Fixation for Mandibular Orthognathic Surgery.

    Stringhini, Diego José; Sommerfeld, Ricardo; Uetanabaro, Lucas Caetano; Leonardi, Denise Piotto; Araújo, Melissa Rodrigues; Rebellato, Nelson Luís Barbosa; Costa, Delson João da; Scariot, Rafaela

    2016-01-01

    The aim of this study was to evaluate the stress and dislodgement resistance by finite element analysis of different types of fixation in mandibular orthognathic surgery. A 3D solid finite element model of a hemi-mandible was obtained. A bilateral sagittal split osteotomy was simulated and the distal segment was advanced 5 mm forward. After the adjustment and superimposing of segments, 9 different types of osteosynthesis with 2.0 miniplates and screws were simulated: A, one 4-hole conventional straight miniplate; B, one 4-hole locking straight miniplate; C, one 4-hole conventional miniplate and one bicortical screw; D, one 4-hole locking miniplate and 1 bicortical screws; E, one 6-hole conventional straight miniplate; F, one 6-hole locking miniplate; G, two 4-hole conventional straight miniplates; H, two 4-hole locking straight miniplates; and I, 3 bicortical screws in an inverted-L pattern. In each model, forces simulating the masticatory muscles were applied. The values of stress in the plates and screws were checked. The dislodgement resistance was checked at the proximal segment since the distal segment was stable because of the screen at the occlusal tooth. The regions with the lowest and highest displacement were measured. The offset between the osteotomized segments was verified by millimeter intervals. Inverted-L with bicortical screws was the model that had the lowest dislodgment and the model with the lowest tension was the one with two conventional plates. The results suggest that the tension was better distributed in the locking miniplates, but the locking screws presented higher concentration of tension. PMID:27224561

  15. Association and Heritability Studies for Drought Resistance under Varied Moisture Stress Regimes in Backcross Inbred Population of Rice

    R SELLAMMAL; S ROBIN; M RAVEENDRAN

    2014-01-01

    Drought stress is one of the major constraints affecting rice production and yield stability in the rainfed regions. To understand the physiological basis of drought resistance related component traits, we used a backcross inbred population of rice under three kinds of moisture regimes viz., non-stress, moderate (24.48%) and severe stress (73.97%) conditions which reflect the differential responses of the genotypes to varying stress intensities. The plot yield, 1000-grain weight, panicle exsertion and canopy air temperature difference exhibited high heritability under the control conditions, whereas spikelet sterility and single plant yield exhibited high heritability under the moderate stress conditions. Traits such as days to 50% flowering, plant height and osmotic potential showed high heritability under the severe stress conditions. Plot yield under stress was significantly and positively correlated with harvest index and 1000-grain weight, but negatively associated with leaf rolling score and days to 50% flowering. The drought susceptibility index and drought response index were negatively correlated between each other both under the moderate and severe stress conditions. The derived traits viz., difference in panicle length between the control and the severe stress was associated with osmotic adjustment measured under field conditions. Difference in plant height and panicle length was negatively associated with plot yield under stress.

  16. fungal disease resistance in vicia faba in relation to water stress and gamma irradiation

    Induced systemic resistance (Isr), as a recent strategy, achieving biological control of plant disease through initiation to form natural antibiotic compounds, phytoalexin, that considered to be involved in the defense mechanism of plant to potential pathogen. Also, phytoalexin formed by leguminosae in response to infection play an extremely role in disease resistance. Indeed, wyerone acid (C14H12O4) has been clearfield as a phytoalexin formed by Vicia faba in response to infection stress. Therefore, the present study was outlined to clearify the feasibility to biocontrol of checolate spot disease caused by Botrytis fabae in faba bean, Vicia faba, plants under field condition. Pre. Sowing seed irradiated with low gamma ray were planted in: 1- Three pot experiments (salinity-Ni-Si) in complete randomized block design in three replicates. 2- Two field experiments in loam soil irrigated with river nile water (inducers-Isr)) in splite-plot design in three replicates. 3- Two field experiments in sandy soil irrigated with two saline water from 2 shallow-wells (inducers-Isr) in split-split plot design in three replicates

  17. Metallurgical and mechanical parameters controlling alloy 718 stress corrosion cracking resistance in PWR primary water

    Improving the performance and reliability of the fuel assemblies of the pressurized water reactors requires having a perfect knowledge of the operating margins of both the components and the materials. The choice of alloy 718 as reference material for this study is justified by the industrial will to identify the first order parameters controlling the excellent resistance of this alloy to Stress Corrosion Cracking (SCC). For this purpose, a specific slow strain rate (SSR) crack initiation test using tensile specimen with a V-shaped hump in the middle of the gauge length was developed and modeled. The selectivity of such SSR tests in simulated PWR primary water at 350 C was clearly established by characterizing the SCC resistance of nine alloy 718 thin strip heats. Regardless of their origin and in spite of a similar thermo-mechanical history, they did not exhibit the same susceptibility to SCC crack initiation. All the characterized alloy 718 heats develop oxide scale of similar nature for various exposure times to PWR primary medium in the temperature range [320 C - 360 C]. δ phase precipitation has no impact on alloy 718 SCC initiation behavior when exposed to PWR primary water, contrary to interstitial contents and the triggering of plastic instabilities (PLC phenomenon). (author)

  18. Plant resistance to cold stress: Mechanisms and environmental signals triggering frost hardening and dehardening

    Erwin H Beck; Richard Heim; Jens Hansen

    2004-12-01

    This introductory overview shows that cold, in particular frost, stresses a plant in manifold ways and that the plant’s response, being injurious or adaptive, must be considered a syndrome rather than a single reaction. In the course of the year perennial plants of the temperate climate zones undergo frost hardening in autumn and dehardening in spring. Using Scots pine (Pinus sylvestris L.) as a model plant the environmental signals inducing frost hardening and dehardening, respectively, were investigated. Over 2 years the changes in frost resistance of Scots pine needles were recorded together with the annual courses of day-length and ambient temperature. Both act as environmental signals for frost hardening and dehardening. Climate chamber experiments showed that short day-length as a signal triggering frost hardening could be replaced by irradiation with far red light, while red light inhibited hardening. The involvement of phytochrome as a signal receptor could be corroborated by respective night-break experiments. More rapid frost hardening than by short day or far red treatment was achieved by applying a short period (6 h) of mild frost which did not exceed the plant’s cold resistance. Both types of signals were independently effective but the rates of frost hardening were not additive. The maximal rate of hardening was – 0.93°C per day and frost tolerance of < – 72°C was achieved. For dehardening, temperature was an even more effective signal than day-length.

  19. ZmNAC55, a maize stress-responsive NAC transcription factor, confers drought resistance in transgenic Arabidopsis.

    Mao, Hude; Yu, Lijuan; Han, Ran; Li, Zhanjie; Liu, Hui

    2016-08-01

    Abiotic stress has been shown to significantly limit the growth and productivity of crops. NAC transcription factors play essential roles in response to various abiotic stresses. However, only little information regarding stress-related NAC genes is available in maize. Here, we cloned a maize NAC transcription factor ZmNAC55 and identified its function in drought stress. Transient expression and transactivation assay demonstrated that ZmNAC55 was localized in the nucleus and had transactivation activity. Expression analysis of ZmNAC55 in maize showed that this gene was induced by drought, high salinity and cold stresses and by abscisic acid (ABA). Promoter analysis demonstrated that multiple stress-related cis-acting elements exist in promoter region of ZmNAC55. Overexpression of ZmNAC55 in Arabidopsis led to hypersensitivity to ABA at the germination stage, but enhanced drought resistence compared to wild-type seedlings. Transcriptome analysis identified a number of differentially expressed genes between 35S::ZmNAC55 transgenic and wild-type plants, and many of which are involved in stress response, including twelve qRT-PCR confirmed well-known drought-responsive genes. These results highlight the important role of ZmNAC55 in positive regulates of drought resistence, and may have potential applications in transgenic breeding of drought-tolerant crops. PMID:27085597

  20. Induction of multixenobiotic defense mechanisms in resistant Daphnia magna clones as a general cellular response to stress.

    Jordão, Rita; Campos, Bruno; Lemos, Marco F L; Soares, Amadeu M V M; Tauler, Romà; Barata, Carlos

    2016-06-01

    Multixenobiotic resistance mechanisms (MXR) were recently identified in Daphnia magna. Previous results characterized gene transcripts of genes encoding and efflux activities of four putative ABCB1 and ABCC transporters that were chemically induced but showed low specificity against model transporter substrates and inhibitors, thus preventing us from distinguishing between activities of different efflux transporter types. In this study we report on the specificity of induction of ABC transporters and of the stress protein hsp70 in clones selected to be genetically resistant to ABCB1 chemical substrates. Clones resistant to mitoxantrone, ivermectin and pentachlorophenol showed distinctive transcriptional responses of transporter protein coding genes and of putative transporter dye activities. Expression of hsp70 proteins also varied across resistant clones. Clones resistant to mitoxantrone and pentachlorophenol showed high constitutive levels of hsp70. Transcriptional levels of the abcb1 gene transporter and of putative dye transporter activity were also induced to a greater extent in the pentachlorophenol resistant clone. Observed higher dye transporter activities in individuals from clones resistant to mitoxantrone and ivermectin were unrelated with transcriptional levels of the studied four abcc and abcb1 transporter genes. These findings suggest that Abcb1 induction in D. magna may be a part of a general cellular stress response. PMID:27039215

  1. Differential gene expression profiling of Listeria monocytogenes in Cacciatore and Felino salami to reveal potential stress resistance biomarkers.

    Mataragas, M; Rovetto, F; Bellio, A; Alessandria, V; Rantsiou, K; Decastelli, L; Cocolin, L

    2015-04-01

    The current study reports a) the in situ transcriptional profiles of Listeria monocytogenes in response to fermented sausage stress and b) an approach in which in situ RT-qPCR data have been combined with advanced statistical techniques to discover potential stress resistance or cell viability biomarkers. Gene expression profiling of the pathogen has been investigated using RT-qPCR to understand how L. monocytogenes responds to the conditions encountered during the fermentation and ripening of sausages. A cocktail of five L. monocytogenes strains was inoculated into the batter of Cacciatore and Felino sausages. The RT-qPCR data showed that the acidic and osmotic stress-related genes were up-regulated. The transcripts of the lmo0669 gene increased during the fermentation and ripening of Cacciatore, whereas gbuA and lmo1421 were up-regulated during the ripening of Felino and Cacciatore, respectively. sigB expression was induced in both sausages throughout the whole process. Finally, the virulence-related gene prfA was down-regulated during the fermentation of Cacciatore. The multivariate gene expression profiling analysis suggested that sigB and lmo1421 or sigB and gbuA could be used as different types of stress resistance biomarkers to track, for example, stress resistance or cell viability in fermented sausages with short (Cacciatore) or long (Felino) maturation times, respectively. PMID:25475310

  2. A peroxiredoxin, PRDX-2, is required for insulin secretion and insulin/IIS-dependent regulation of stress resistance and longevity.

    Oláhová, Monika; Veal, Elizabeth A

    2015-08-01

    Peroxiredoxins (Prx) are abundant thiol peroxidases with a conserved anti-ageing role. In contrast to most animals, the nematode worm, Caenorhabditis elegans, encodes a single cytosolic 2-Cys Prx, PRDX-2, rendering it an excellent model for examining how peroxiredoxins affect animal physiology and ageing. Our previous work revealed that, although PRDX-2 protects against the toxicity of peroxides, enigmatically, prdx-2-mutant animals are hyper-resistant to other forms of oxidative stress. Here, we have investigated the basis for this increased resistance. Mammalian FOXO and Nrf2 transcription factors directly promote the expression of a range of detoxification enzymes. We show that the FOXO orthologue, DAF-16, and the Nrf2 orthologue, SKN-1, are required for the increased stress resistance of prdx-2-mutant worms. Our data suggest that PRDX-2 is required for normal levels of insulin secretion and hence the inhibition of DAF-16 and SKN-1 by insulin/IGF-1-like signalling (IIS) under nutrient-rich conditions. Intriguingly, loss of PRDX-2 increases DAF-16 and SKN-1 activities sufficiently to increase arsenite resistance without initiating other IIS-inhibited processes. Together, these data suggest that loss of peroxiredoxin function may increase stress resistance by reducing insulin secretion, but that further changes in insulin signalling are required for the reprogramming of development and fat metabolism. In addition, we reveal that the temperature-dependent prolongevity function of PRDX-2 is required for the extended lifespan associated with several pathways, including further reductions in IIS. PMID:25808059

  3. Green Synthesis of Oxovanadium(IV)/chitosan Nanocomposites and Its Ameliorative Effect on Hyperglycemia, Insulin Resistance, and Oxidative Stress.

    Liu, Yanjun; Jie, Xu; Guo, Yongli; Zhang, Xin; Wang, Jingfeng; Xue, Changhu

    2016-02-01

    In this paper, the preparation, characterization, and ameliorative effect on high-fat high-sucrose diet-induced hyperglycemia, insulin resistance, oxidative stress in mice of novel oxovanadium(IV)/chitosan (OV/CS) nanocomposites were investigated. The nanobiocomposite was produced by chemical reduction by chitosan and L-ascorbic acid using microwave heating, under environment-friendly conditions, using aqueous solutions, and notably, by using both mediators as reducing and stabilizing agents. In addition, OV/CS nanocomposites were characterized by transmission electron microscopy, energy dispersive spectroscopy, particle size, and zeta potential measurements. In vivo experiments were designed to examine whether the OV/CS nanocomposites would provide additional benefits on oxidative stress, hyperglycemia, and insulin resistance in mice with type 2 diabetes. The results rendered insulin resistant by treating with OV/CS nanocomposites alleviate insulin resistance and improve oxidative stress. Such nanocomposite seem to be a valuable therapy to achieve and/or maintain glycemic control and therapeutic agents in the treatment arsenal for insulin resistance and type 2 diabetes. PMID:26144273

  4. Benefits of thread rolling process to the stress corrosion cracking and fatigue resistance of high strength fasteners

    The stress corrosion cracking (SCC) behavior of thread rolled in contrast to cut (machined) Alloy X-750 and Alloy 625 fasteners in a simulated high temperature primary water environment has been evaluated. SCC testing at 360 degrees C and 338 degrees C included 157 small and 40 large 60 degrees. Vee thread studs. Most of the test studs had rolled threads (128 in number) while the remainder (69 in number) had cut threads to provide a baseline for a comparison of SCC initiation resistance. Thread rolled fasteners exhibited improved resistance relative to cut fasteners of the same material condition in terms of both SCC initiation life and applied stress. Tests of fatigue resistance in air at room temperature and both air and primary water at 315 degrees C were conducted on the smaller studs with both cut and rolled threads. Results have shown rolled threads can have significantly improved fatigue lives over those of cut threads in both air and primary water

  5. Ion beam modification of thermal stress resistance of MgO single crystals with different crystallographic faces

    Ion beam modification of thermal shock stress resistance of MgO single crystals with various crystallographic faces is investigated. The most stable crystal faces in terms of stress and damage resistance are established. Ion implantation is shown to reduce the temperature threshold of fracture for all crystal faces tested. The (111) face is demonstrated to be of highest stability compared to (110) and (100) faces in both implanted and unimplanted crystals. At the same time ion implantation substantially increases the microcrack density for all the faces tested and reduces the degree of fracture damage following thermal shock. The theoretical resistance parameters for various crystal faces are calculated using the continuum mechanics approach. The results are discussed on the basis of fracture mechanics principles and the effect of the implantation-induced lattice damage on crack nucleation

  6. The Candida albicans Histone Acetyltransferase Hat1 Regulates Stress Resistance and Virulence via Distinct Chromatin Assembly Pathways.

    Michael Tscherner

    2015-10-01

    Full Text Available Human fungal pathogens like Candida albicans respond to host immune surveillance by rapidly adapting their transcriptional programs. Chromatin assembly factors are involved in the regulation of stress genes by modulating the histone density at these loci. Here, we report a novel role for the chromatin assembly-associated histone acetyltransferase complex NuB4 in regulating oxidative stress resistance, antifungal drug tolerance and virulence in C. albicans. Strikingly, depletion of the NuB4 catalytic subunit, the histone acetyltransferase Hat1, markedly increases resistance to oxidative stress and tolerance to azole antifungals. Hydrogen peroxide resistance in cells lacking Hat1 results from higher induction rates of oxidative stress gene expression, accompanied by reduced histone density as well as subsequent increased RNA polymerase recruitment. Furthermore, hat1Δ/Δ cells, despite showing growth defects in vitro, display reduced susceptibility to reactive oxygen-mediated killing by innate immune cells. Thus, clearance from infected mice is delayed although cells lacking Hat1 are severely compromised in killing the host. Interestingly, increased oxidative stress resistance and azole tolerance are phenocopied by the loss of histone chaperone complexes CAF-1 and HIR, respectively, suggesting a central role for NuB4 in the delivery of histones destined for chromatin assembly via distinct pathways. Remarkably, the oxidative stress phenotype of hat1Δ/Δ cells is a species-specific trait only found in C. albicans and members of the CTG clade. The reduced azole susceptibility appears to be conserved in a wider range of fungi. Thus, our work demonstrates how highly conserved chromatin assembly pathways can acquire new functions in pathogenic fungi during coevolution with the host.

  7. The overexpression of an Amaranthus hypochondriacus NF-YC gene modifies growth and confers water deficit stress resistance in Arabidopsis.

    Palmeros-Suárez, Paola A; Massange-Sánchez, Julio A; Martínez-Gallardo, Norma A; Montero-Vargas, Josaphat M; Gómez-Leyva, Juan F; Délano-Frier, John P

    2015-11-01

    Nuclear factor-Y (NF-Y), is a plant heterotrimeric transcription factor constituted by NF-YA, NF-YB and NF-YC subunits. The function of many NF-Y subunits, mostly of the A and B type, has been studied in plants, but knowledge regarding the C subunit remains fragmentary. Here, a water stress-induced NF-YC gene from Amaranthus hypochondriacus (AhNF-YC) was further characterized by its overexpression in transgenic Arabidospis thaliana plants. A role in development was inferred from modified growth rates in root, rosettes and inflorescences recorded in AhNF-YC overexpressing Arabidopsis plants, in addition to a delayed onset of flowering. Also, the overexpression of AhNF-YC caused increased seedling sensitivity to abscisic acid (ABA), and influenced the expression of several genes involved in secondary metabolism, development and ABA-related responses. An altered expression of the latter in water stressed and recovered transgenic plants, together with the observed increase in ABA sensitivity, suggested that their increased water stress resistance was partly ABA-dependent. An untargeted metabolomic analysis also revealed an altered metabolite pattern, both in normal and water stress/recovery conditions. These results suggest that AhNF-YC may play an important regulatory role in both development and stress, and represents a candidate gene for the engineering of abiotic stress resistance in commercial crops. PMID:26475185

  8. Artemisia annua increases resistance to heat and oxidative stresses, but has no effect on lifespan in Caenorhabditis elegans

    Seung-Il OH

    2016-01-01

    Full Text Available Abstract It is suggested that oxidative stress induced by cellular reactive oxygen species is one of the major causal factors of aging. The effect of dietary supplementation of anti-oxidants on response to environmental stressors and lifespan has been studied in various model organisms. In the present study, we examine the effect of Artemisia annua extract on resistance to oxidative, heat, and ultraviolet stresses in the nematode Caenorhabditis elegans. Artemisia annua significantly increases survival under oxidative and heat stresses, however has no effects in response to ultraviolet stress. Then, we measured the in vivo changes in expression of stress-responsive genes by Artemisia annua using green fluorescence protein. The expression of hsp-16.2, known to be involved in response to heat stress, is significantly increased by Artemisia annua supplementation. An anti-oxidant gene, sod-3, was also up-regulated by Artemisia annua. However, both mean and maximum lifespan of Caenorhabditis elegans was not altered by dietary supplementation of Artemisia annua. These findings indicate that Artemisia annua confers health-promoting effects through increasing the resistance to environmental stressors and has no effect on lifespan in C. elegans. Our study suggests that Artemisia annua can be used for the development of novel natural therapeutics for diseases caused by environmental stressors.

  9. Induction of a stress response in Lactococcus lactis is associated with a resistance to ribosomally active antibiotics.

    Dorrian, James M; Briggs, Deborah A; Ridley, Michael L; Layfield, Robert; Kerr, Ian D

    2011-11-01

    The acquisition of multidrug resistance in bacteria underlies the failure of antimicrobial therapy, and the emergence of pathogens that are resistant to almost the entire armoury of antibiotics. Among the proteins that can mediate or contribute to the drug-resistance profile in Gram-positive bacteria is a subset of ATP-binding cassette proteins that are comprised of a tandem-repeated nucleotide-binding domain. In this study, we expressed one of these NBD(2) proteins, LmrC, in an antibiotic-sensitive Gram-positive host strain (Lactococcus lactis) and demonstrated the acquisition of resistance to ribosomally active antibiotics. Mutation of key catalytic residues suggested that the resistance profile was the result of a cellular response, rather than being a function of the NBD(2) protein itself. This observation was confirmed by 2D SDS/PAGE, which demonstrated that the expression of the NBD(2) protein induced a stress response in L. lactis. A model combining this stress response induction and the acquisition of antibiotic resistance is proposed. PMID:21848804

  10. Sphingoid bases inhibit acid-induced demineralization of hydroxyapatite.

    Valentijn-Benz, Marianne; van 't Hof, Wim; Bikker, Floris J; Nazmi, Kamran; Brand, Henk S; Sotres, Javier; Lindh, Liselott; Arnebrant, Thomas; Veerman, Enno C I

    2015-01-01

    Calcium hydroxyapatite (HAp), the main constituent of dental enamel, is inherently susceptible to the etching and dissolving action of acids, resulting in tooth decay such as dental caries and dental erosion. Since the prevalence of erosive wear is gradually increasing, there is urgent need for agents that protect the enamel against erosive attacks. In the present study we studied in vitro the anti-erosive effects of a number of sphingolipids and sphingoid bases, which form the backbone of sphingolipids. Pretreatment of HAp discs with sphingosine, phytosphingosine (PHS), PHS phosphate and sphinganine significantly protected these against acid-induced demineralization by 80 ± 17%, 78 ± 17%, 78 ± 7% and 81 ± 8%, respectively (p < 0.001). On the other hand, sphingomyelin, acetyl PHS, octanoyl PHS and stearoyl PHS had no anti-erosive effects. Atomic force measurement revealed that HAp discs treated with PHS were almost completely and homogeneously covered by patches of PHS. This suggests that PHS and other sphingoid bases form layers on the surface of HAp, which act as diffusion barriers against H(+) ions. In principle, these anti-erosive properties make PHS and related sphingosines promising and attractive candidates as ingredients in oral care products. PMID:25300299

  11. Metformin protects rat hepatocytes against bile acid-induced apoptosis.

    Titia E Woudenberg-Vrenken

    Full Text Available BACKGROUND: Metformin is used in the treatment of Diabetes Mellitus type II and improves liver function in patients with non-alcoholic fatty liver disease (NAFLD. Metformin activates AMP-activated protein kinase (AMPK, the cellular energy sensor that is sensitive to changes in the AMP/ATP-ratio. AMPK is an inhibitor of mammalian target of rapamycin (mTOR. Both AMPK and mTOR are able to modulate cell death. AIM: To evaluate the effects of metformin on hepatocyte cell death. METHODS: Apoptotic cell death was induced in primary rat hepatocytes using either the bile acid glycochenodeoxycholic acid (GCDCA or TNFα in combination with actinomycin D (actD. AMPK, mTOR and phosphoinositide-3 kinase (PI3K/Akt were inhibited using pharmacological inhibitors. Apoptosis and necrosis were quantified by caspase activation, acridine orange staining and Sytox green staining respectively. RESULTS: Metformin dose-dependently reduces GCDCA-induced apoptosis, even when added 2 hours after GCDCA, without increasing necrotic cell death. Metformin does not protect against TNFα/ActD-induced apoptosis. The protective effect of metformin is dependent on an intact PI3-kinase/Akt pathway, but does not require AMPK/mTOR-signaling. Metformin does not inhibit NF-κB activation. CONCLUSION: Metformin protects against bile acid-induced apoptosis and could be considered in the treatment of chronic liver diseases accompanied by inflammation.

  12. Gene-related strain variation of Staphylococcus aureus for homologous resistance response to acid stress.

    Lee, Soomin; Ahn, Sooyeon; Lee, Heeyoung; Kim, Won-Il; Kim, Hwang-Yong; Ryu, Jae-Gee; Kim, Se-Ri; Choi, Kyoung-Hee; Yoon, Yohan

    2014-10-01

    This study investigated the effect of adaptation of Staphylococcus aureus strains to the acidic condition of tomato in response to environmental stresses, such as heat and acid. S. aureus ATCC 13565, ATCC 14458, ATCC 23235, ATCC 27664, and NCCP10826 habituated in tomato extract at 35°C for 24 h were inoculated in tryptic soy broth. The culture suspensions were then subjected to heat challenge or acid challenge at 60°C and pH 3.0, respectively, for 60 min. In addition, transcriptional analysis using quantitative real-time PCR was performed to evaluate the expression level of acid-shock genes, such as clpB, zwf, nuoF, and gnd, from five S. aureus strains after the acid habituation of strains in tomato at 35°C for 15 min and 60 min in comparison with that of the nonhabituated strains. In comparison with the nonhabituated strains, the five tomato-habituated S. aureus strains did not show cross protection to heat, but tomato-habituated S. aureus ATCC 23235 showed acid resistance. In quantitative real-time-PCR analysis, the relative expression levels of acid-shock genes (clpB, zwf, nuoF, and gnd) were increased the most in S. aureus ATCC 23235 after 60 min of tomato habituation, but there was little difference in the expression levels among the five S. aureus strains after 15 min of tomato habituation. These results indicate that the variation of acid resistance of S. aureus is related to the expression of acid-shock genes during acid habituation. PMID:25285500

  13. Supplementing dietary sugar promotes endoplasmic reticulum stress-independent insulin resistance and fatty liver in goose.

    Geng, Tuoyu; Zhao, Xing; Xia, Lili; Liu, Long; Li, Fuyuan; Yang, Biao; Wang, Qianqian; Montgomery, Sean; Cui, Hengmi; Gong, Daoqing

    2016-08-01

    It is known that endoplasmic reticulum stress (ERS) contributes to insulin resistance (IR) and non-alcoholic fatty liver disease (NAFLD) in mammals. However, we recently demonstrated that overfeeding with a traditional diet (mainly consisting of cooked maize) does not induce ERS in goose. As cellular studies show that high glucose and palmitate can trigger ERS in mammalian cells, we hypothesized that supplementing sugar to the traditional diet could induce ERS, thus promoting insulin resistance and fatty liver. To test the hypothesis, we first treated goose primary hepatocytes with high glucose (25 mM and 50 mM) and palmitate (0.5 mM) supplemented with or without 0.25 mM oleate. Data indicated that, as in mammalian cells, high glucose and palmitate indeed induced ERS in goose primary hepatocytes, and palmitate-induced ERS was suppressed by supplemental 0.25 mM oleate. We then tested the hypothesis with an in vivo study, in which Landes geese overfed with traditional or novel diets (i.e., the traditional diet supplemented with sugar) were compared with control geese (normally fed with cooked maize) for ERS, IR and fatty liver. The differences in glucose tolerance, insulin tolerance and postprandial blood glucose between the geese overfed with traditional and novel diets suggested that supplementing dietary sugar promoted IR. This promotion was accompanied with an increasing trend of liver weight and abdominal fat weight relative to body weight. Surprisingly, compared to overfeeding with the traditional diet, overfeeding with the novel diet did not induce ERS, even further suppressed ERS in goose fatty liver. Together, our findings suggest that supplementing dietary sugar promotes ERS-independent IR and fatty liver in goose. It is intriguing to discover the factor(s) protecting goose liver from ERS as well as the non-ERS mechanism underlying IR. PMID:27246737

  14. Mitogen-activated protein kinase-activated protein kinase 2 mediates resistance to Hydrogen peroxide-induced oxidative stress in Human hepatobiliary Cancer cells

    Nguyen Ho-Bouldoires, Thang Huong; Clapéron, Audrey; Mergey, Martine; Wendum, Dominique; Desbois-Mouthon, Christèle; Tahraoui, Sylvana; Fartoux, Laetitia; Chettouh, Hamza; Merabtene, Fatiha; Scatton, Olivier; Gaestel, Matthias; Praz, Françoise; Housset, Chantal; Fouassier, Laura

    2015-01-01

    The development and progression of liver cancer are characterized by increased levels of reactive oxygen species (ROS). ROS-induced oxidative stress impairs cell proliferation and ultimately leads to cell death. Although liver cancer cells are especially resistant to oxidative stress, mechanisms of such resistance remain understudied. We identified the MAPK-activated protein kinase 2 (MK2)/Heat shock protein 27 (Hsp27) signaling pathway mediating defenses against oxidative stress. Besides to ...

  15. Feeding Drosophila a biotin-deficient diet for multiple generations increases stress resistance and lifespan and alters gene expression and histone biotinylation patterns 1,2

    Smith, Erin M; Hoi, Jia Tse; Eissenberg, Joel C.; Shoemaker, James D.; Neckameyer, Wendi S; Ilvarsonn, Anne M.; Harshman, Lawrence G.; Schlegel, Vicki L.; Zempleni, Janos

    2007-01-01

    Caloric restriction increases stress resistance and lifespan in Drosophila melanogaster and other species. The roles of individual nutrients in stress resistance and longevity are largely unknown. The vitamin biotin is a potential candidate for mediating these effects, given its known roles in stress signaling and gene regulation by epigenetic mechanisms, i.e., biotinylation of histones. Here, we tested the hypothesis that prolonged culture of Drosophila on biotin-deficient medium increases s...

  16. Transcriptome Profiling Revealed Stress-Induced and Disease Resistance Genes Up-Regulated in PRSV Resistant Transgenic Papaya

    Fang, Jingping; Lin, Aiting; Qiu, Weijing; Cai, Hanyang; Umar, Muhammad; Chen, Rukai; Ming, Ray

    2016-01-01

    Papaya is a productive and nutritious tropical fruit. Papaya Ringspot Virus (PRSV) is the most devastating pathogen threatening papaya production worldwide. Development of transgenic resistant varieties is the most effective strategy to control this disease. However, little is known about the genome-wide functional changes induced by particle bombardment transformation. We conducted transcriptome sequencing of PRSV resistant transgenic papaya SunUp and its PRSV susceptible progenitor Sunset t...

  17. Benefits of thread rolling process to the stress corrosion cracking and fatigue resistance of high strength fasteners

    Kephart, A.R.; Hayden, S.Z.

    1993-05-01

    Stress corrosion cracking (SCC) behavior of cut (machined) vice thread rolled Alloy X-750 and Alloy 625 fasteners in a simulated high temperature primary water environment has been evaluated. SCC testing at 360 and 338C included 157 small and 40 large 60{degree} Vee thread studs. Thread rolled fasteners had improved resistance relative to cut fasteners. Tests of fatigue resistance in air at room temperature and both air and primary water at 315C were conducted on smaller studs with both cut and rolled threads. Results showed rolled threads can have significantly improved fatigue lives over those of cut threads in both air and primary water. Fasteners produced by two different thread rolling methods, in-feed (radial) and through-feed (axial), revealed similar SCC initiation test results. Testing of thread rolled fasteners revealed no significant SCC or fatigue growth of rolling induced thread crest laps typical of the thread rolling process. While fatigue resistance differed between the two rolled thread supplier`s studs, neither of the suppliers studs showed SCC initiation at exposure times beyond that of cut threads with SCC. In contrast to rolling at room temperature, warm rolled (427C) threads showed no improvement over cut threads in terms of fatigue resistance. The observed improved SCC and fatigue performance of rolled threads is postulated to be due to interactive factors, including beneficial residual stresses in critically stressed thread root region, reduction of plastic strains during loading and formation of favorable microstructure.

  18. Meiotic chromosome mobility in fission yeast is resistant to environmental stress

    Illner, Doris; Lorenz, Alexander; Scherthan, Harry

    2016-01-01

    The formation of healthy gametes requires pairing of homologous chromosomes (homologs) as a prerequisite for their correct segregation during meiosis. Initially, homolog alignment is promoted by meiotic chromosome movements feeding into intimate homolog pairing by homologous recombination and/or synaptonemal complex formation. Meiotic chromosome movements in the fission yeast, Schizosaccharomyces pombe, depend on astral microtubule dynamics that drag the nucleus through the zygote; known as horsetail movement. The response of microtubule-led meiotic chromosome movements to environmental stresses such as ionizing irradiation (IR) and associated reactive oxygen species (ROS) is not known. Here, we show that, in contrast to budding yeast, the horsetail movement is largely radiation-resistant, which is likely mediated by a potent antioxidant defense. IR exposure of sporulating S. pombe cells induced misrepair and irreparable DNA double strand breaks causing chromosome fragmentation, missegregation and gamete death. Comparing radiation outcome in fission and budding yeast, and studying meiosis with poisoned microtubules indicates that the increased gamete death after IR is innate to fission yeast. Inhibition of meiotic chromosome mobility in the face of IR failed to influence the course of DSB repair, indicating that paralysis of meiotic chromosome mobility in a genotoxic environment is not a universal response among species. PMID:27074839

  19. Meiotic chromosome mobility in fission yeast is resistant to environmental stress.

    Illner, Doris; Lorenz, Alexander; Scherthan, Harry

    2016-01-01

    The formation of healthy gametes requires pairing of homologous chromosomes (homologs) as a prerequisite for their correct segregation during meiosis. Initially, homolog alignment is promoted by meiotic chromosome movements feeding into intimate homolog pairing by homologous recombination and/or synaptonemal complex formation. Meiotic chromosome movements in the fission yeast, Schizosaccharomyces pombe, depend on astral microtubule dynamics that drag the nucleus through the zygote; known as horsetail movement. The response of microtubule-led meiotic chromosome movements to environmental stresses such as ionizing irradiation (IR) and associated reactive oxygen species (ROS) is not known. Here, we show that, in contrast to budding yeast, the horsetail movement is largely radiation-resistant, which is likely mediated by a potent antioxidant defense. IR exposure of sporulating S. pombe cells induced misrepair and irreparable DNA double strand breaks causing chromosome fragmentation, missegregation and gamete death. Comparing radiation outcome in fission and budding yeast, and studying meiosis with poisoned microtubules indicates that the increased gamete death after IR is innate to fission yeast. Inhibition of meiotic chromosome mobility in the face of IR failed to influence the course of DSB repair, indicating that paralysis of meiotic chromosome mobility in a genotoxic environment is not a universal response among species. PMID:27074839

  20. Research on the decreased resistance of concrete under traction by detection of stress wave emission

    The recording of the cumulated stress wave emission counting from a concrete specimen under increasing load shows angular points which appear at well-defined fractions of the breaking strength and mark the limits of 4 distinct phases: compression stage for: 0resistance in traction if the compression has remained below the appearance of this characteristic elbow. Finally the Kaiser effect distinguished by an SWE appearing only above the maximum load previously attained can supply information on earlier loads

  1. Effects of ginger (Zingiber officinale Roscoe supplementation and resistance training on some blood oxidative stress markers in obese men

    Sirvan Atashak

    2014-06-01

    Full Text Available Excessive adiposity increases oxidative stress, and thus may play a critical role in the pathogenesis and development of obesity-associated comorbidities, in particular atherosclerosis, diabetes mellitus, and arterial hypertension. Improved body composition, through exercise training and diet, may therefore significantly contribute to a reduction in oxidative stress. Further, some foods high in antioxidants (e.g., ginger provide additional defense against oxidation. This study was conducted to assess the effects of ginger (Zingiber officinale Roscoe supplementation and progressive resistance training (PRT on some nonenzymatic blood [total antioxidant capacity (TAC and malondialdehyde (MDA] oxidative stress markers in obese men. Thirty-two obese males (body mass index ≥30, aged 18–30 years were randomized to one of the following four groups: a placebo (PL; n = 8; resistance training plus placebo (RTPL; n = 8; resistance training plus ginger supplementation (RTGI; n = 8; and ginger supplementation only (GI; n = 8. Participants in the RTGI and GI groups consumed 1 g ginger/day for 10 weeks. At the same time, PRT was undertaken by the RTPL and RTGI groups three times/week. Resting blood samples were collected at baseline and at 10 weeks, and analyzed for plasma nonenzymatic TAC and MDA concentration. After the 10-week intervention, we observed significant training × ginger supplementation × resistance training interaction for TAC (p = 0.043 and significant interactions for training × resistance training and training × ginger supplementation for MDA levels (p < 0.05. The results of this study show that 10 weeks of either ginger supplementation or PRT protects against oxidative stress and therefore both of these interventions can be beneficial for obese individuals; however, when combined, the effects cancel each other out.

  2. Resistance to Aspergillus flavus in maize and peanut:Molecular biology, breeding, environmental stress,and future perspectives

    Jake; C.Fountain; Pawan; Khera; Liming; Yang; Spurthi; N.Nayak; Brian; T.Scully; Robert; D.Lee; Zhi-Yuan; Chen; Robert; C.Kemerait; Rajeev; K.Varshney; Baozhu; Guo

    2015-01-01

    The colonization of maize(Zea mays L.) and peanut(Arachis hypogaea L.) by the fungal pathogen Aspergillus flavus results in the contamination of kernels with carcinogenic mycotoxins known as aflatoxins leading to economic losses and potential health threats to humans. The regulation of aflatoxin biosynthesis in various Aspergillus spp. has been extensively studied, and has been shown to be related to oxidative stress responses. Given that environmental stresses such as drought and heat stress result in the accumulation of reactive oxygen species(ROS) within host plant tissues, host-derived ROS may play an important role in cross-kingdom communication between host plants and A. flavus. Recent technological advances in plant breeding have provided the tools necessary to study and apply knowledge derived from metabolomic, proteomic, and transcriptomic studies in the context of productive breeding populations. Here, we review the current understanding of the potential roles of environmental stress, ROS, and aflatoxin in the interaction between A.flavus and its host plants, and the current status in molecular breeding and marker discovery for resistance to A. flavus colonization and aflatoxin contamination in maize and peanut. We will also propose future directions and a working model for continuing research efforts linking environmental stress tolerance and aflatoxin contamination resistance in maize and peanut.

  3. Resistance to Aspergillus flavus in maize and peanut:Molecular biology, breeding, environmental stress, and future perspectives

    Jake C. Fountain; Baozhu Guo; Pawan Khera; Liming Yang; Spurthi N. Nayak; Brian T. Scully; Robert D. Lee; Zhi-Yuan Chen; Robert C. Kemerait; Rajeev K. Varshney

    2015-01-01

    The colonization of maize (Zea mays L.) and peanut (Arachis hypogaea L.) by the fungal pathogen Aspergillus flavus results in the contamination of kernels with carcinogenic mycotoxins known as aflatoxins leading to economic losses and potential health threats to humans. The regulation of aflatoxin biosynthesis in various Aspergillus spp. has been extensively studied, and has been shown to be related to oxidative stress responses. Given that environmental stresses such as drought and heat stress result in the accumulation of reactive oxygen species (ROS) within host plant tissues, host-derived ROS may play an important role in cross-kingdom communication between host plants and A. flavus. Recent technological advances in plant breeding have provided the tools necessary to study and apply knowledge derived from metabolomic, proteomic, and transcriptomic studies in the context of productive breeding populations. Here, we review the current understanding of the potential roles of environmental stress, ROS, and aflatoxin in the interaction between A. flavus and its host plants, and the current status in molecular breeding and marker discovery for resistance to A. flavus colonization and aflatoxin contamination in maize and peanut. We will also propose future directions and a working model for continuing research efforts linking environmental stress tolerance and aflatoxin contamination resistance in maize and peanut.

  4. Verification of the resistance of a LEA gene from Tamarix expression in Saccharomyces cerevisiae to abiotic stresses

    WANG Bing-feng; WANG Yu-cheng; ZHANG Da-wei; LI Hong-yan; YANG Chuan-ping

    2008-01-01

    The role of late embryogenesis abundant (LEA) proteins in stress tolerance was examined by using a yeast expression system. LEA protein tolerance to the abotic stresses in plants involved in salt, drought and freezing stresses and additional tolerance to heat, NaHCO3 (salt-alkali) and ultraviolet radiation was also investigated. The transgenic yeast harboring the Tamarix LEA gene (DQ663481) was generated under the control of inducible GAL promoter (pYES2 vector), yeast cells transformed with pYES2 empty vector were also generated as a control. Stress tolerance tests showed that LEA yeast transformants exhibited a higher survival rates than the control transformants under high temperature, NaHCO3, ultraviolet radiation, salt (NaCl), drought and freezing, indicating that the LEA gene is tolerant to these abiotic stresses. These results suggest that the LEA gene is resistant to a wider repertoire of stresses and may play a common role in plant acclimation to the examined stress conditions.

  5. Resilience to stress and disturbance, and resistance to Bromus tectorum l. invasion in cold desert shrublands of western North America

    Chambers, Jeanne C.; Bradley, Bethany A.; Brown, Cynthia S.; D'Antonio, Carla; Germino, Matthew J.; Grace, James B.; Hardegree, Stuart P.; Miller, Richard F.; Pyke, David A.

    2013-01-01

    Alien grass invasions in arid and semi-arid ecosystems are resulting in grass–fire cycles and ecosystem-level transformations that severely diminish ecosystem services. Our capacity to address the rapid and complex changes occurring in these ecosystems can be enhanced by developing an understanding of the environmental factors and ecosystem attributes that determine resilience of native ecosystems to stress and disturbance, and resistance to invasion. Cold desert shrublands occur over strong environmental gradients and exhibit significant differences in resilience and resistance. They provide an excellent opportunity to increase our understanding of these concepts. Herein, we examine a series of linked questions about (a) ecosystem attributes that determine resilience and resistance along environmental gradients, (b) effects of disturbances like livestock grazing and altered fire regimes and of stressors like rapid climate change, rising CO2, and N deposition on resilience and resistance, and (c) interacting effects of resilience and resistance on ecosystems with different environmental conditions. We conclude by providing strategies for the use of resilience and resistance concepts in a management context. At ecological site scales, state and transition models are used to illustrate how differences in resilience and resistance influence potential alternative vegetation states, transitions among states, and thresholds. At landscape scales management strategies based on resilience and resistance—protection, prevention, restoration, and monitoring and adaptive management—are used to determine priority management areas and appropriate actions.

  6. Stress-induced resistance to the fear memory labilization/reconsolidation process. Involvement of the basolateral amygdala complex.

    Espejo, Pablo Javier; Ortiz, Vanesa; Martijena, Irene Delia; Molina, Victor Alejandro

    2016-10-01

    Consolidated memories can enter into a labile state after reactivation followed by a restabilization process defined as reconsolidation. This process can be interfered with Midazolam (MDZ), a positive allosteric modulator of the GABA-A receptor. The present study has evaluated the influence of prior stress on MDZ's interfering effect. We also assessed the influence of both systemic and intra-basolateral amygdala (BLA) infusion of d-cycloserine (DCS), a partial agonist of the NMDA receptors, on the MDZ effect in previously stressed rats. Furthermore, we analyzed the effect of stress on the expression of Zif-268 and the GluN2B sites, two molecular markers of the labilization/reconsolidation process, following reactivation. The results revealed that prior stress resulted into a memory trace that was insensitive to the MDZ impairing effect. Both systemic and intra-BLA DCS administration previous to reactivation restored MDZ's disruptive effect on memory reconsolidation in stressed animals. Further, reactivation enhanced Zif-268 expression in the BLA in control unstressed rats, whereas no elevation was observed in stressed animals. In agreement with the behavioral findings, DCS restored the increased level of Zif-268 expression in the BLA in stressed animals. Moreover, memory reactivation in unstressed animals elevated GluN2B expression in the BLA, thus suggesting that this effect is involved in memory destabilization, whereas stressed animals did not reveal any changes. These findings are consistent with resistance to the MDZ effect in these rats, indicating that stress exposure prevents the onset of destabilization following reactivation. In summary, prior stress limited both the occurrence of the reactivation-induced destabilization and restabilization. PMID:27378335

  7. Nisin Resistance of Listeria monocytogenes Is Increased by Exposure to Salt Stress and Is Mediated via LiaR

    Bergholz, Teresa M.; Tang, Silin; Wiedmann, Martin; Boor, Kathryn J.

    2013-01-01

    Growth of Listeria monocytogenes on refrigerated, ready-to-eat food is a significant food safety concern. Natural antimicrobials, such as nisin, can be used to control this pathogen on food, but little is known about how other food-related stresses may impact how the pathogen responds to these compounds. Prior work demonstrated that exposure of L. monocytogenes to salt stress at 7°C led to increased expression of genes involved in nisin resistance, including the response regulator liaR. We hy...

  8. Effects of simulated microgravity on surfactant and water balance of lung in animals with different resistance to stress

    Bryndina, Irina; Vasilieva, Natalia

    Weightlessness is accompanied by redistribution of blood flow in lung, changes of lung volumes and gas exchange (Prisk et al., 2002; Grigoriev, Baranov, 2003). On the other hand, it is known that microgravity is considered as a kind of moderate stress (Grigoriev et al., 2004). Stress response may differ in animals resistant or vulnerable to stress (Sudakov, 2007). To study the effects of simulated microgravity upon lung, we used 20 male albino rats tested for behavior in the "open field" and than divided into active (stress resistant - SR ) and passive (stress vulnerable - CV) groups. Two mouse lines were used with similar goal - C57Bl/6 and BALB/c mice (n=16). According to data obtained earlier, BALB/c mice referred as more stress vulnerable, in contrast to C57BL/6 mice, which are considered to be relatively stress resistant (Flint et al., 2007). We have previously shown that changes in lung surfactant system after psychosocial stress or long-term immobilization are less pronounced in stress resistant rats (Vasilieva, Bryndina, 2012). The aim of this work is to study the properties and biochemical composition of pulmonary surfactant and lung water balance in rats and mice with different stress resistance in antiorthostatic suspension (AOS) of short and long duration. Simulated microgravity was reproduced according to procedure of Ilyin-Novikov in modification of Morey-Holton. The duration of exposure was 10 days for rats and 30 days for mice. The properties of pulmonary surfactant were assessed by the evaluation of surface activity (surface tension - ST), the content of total phospholipids (PL) and their fractions. Simultaneously we calculated the gravimetric water balance indices: lung coefficient, "dry residue" and wet-to-dry ratio. Total and extravascular lung fluid and pulmonary blood supply were estimated as well. The experiments demonstrated that there was a decrease of surface tension of surfactant films after 10-day AOS in both groups of rats (to a greater

  9. Rapid growth reduces cold resistance: evidence from latitudinal variation in growth rate, cold resistance and stress proteins.

    Robby Stoks

    Full Text Available BACKGROUND: Physiological costs of rapid growth may contribute to the observation that organisms typically grow at submaximal rates. Although, it has been hypothesized that faster growing individuals would do worse in dealing with suboptimal temperatures, this type of cost has never been explored empirically. Furthermore, the mechanistic basis of the physiological costs of rapid growth is largely unexplored. METHODOLOGY/PRINCIPAL FINDING: Larvae of the damselfly Ischnura elegans from two univoltine northern and two multivoltine southern populations were reared at three temperatures and after emergence given a cold shock. Cold resistance, measured by chill coma recovery times in the adult stage, was lower in the southern populations. The faster larval growth rates in the southern populations contributed to this latitudinal pattern in cold resistance. In accordance with their assumed role in cold resistance, Hsp70 levels were lower in the southern populations, and faster growing larvae had lower Hsp70 levels. Yet, individual variation in Hsp70 levels did not explain variation in cold resistance. CONCLUSIONS/SIGNIFICANCE: WE PROVIDE EVIDENCE FOR A NOVEL COST OF RAPID GROWTH: reduced cold resistance. Our results indicate that the reduced cold resistance in southern populations of animals that change voltinism along the latitudinal gradient may not entirely be explained by thermal selection per se but also by the costs of time constraint-induced higher growth rates. This also illustrates that stressors imposed in the larval stage may carry over and shape fitness in the adult stage and highlights the importance of physiological costs in the evolution of life-histories at macro-scales.

  10. Ion beam modification of thermal stress resistance of MgO single crystals with different crystallographic faces

    Ion beam modification of thermal shock stress and damage resistance of MgO single crystals with various crystallographic faces is investigated. The most stable crystal faces in terms of stress and damage resistance are established. Ion implantation is shown to reduce the temperature threshold of fracture for all crystal faces tested. The (111) face is demonstrated to be of highest stability compared to (110) and (100) faces in both implanted and unimplanted crystals. At the same time ion implantation substantially increases the microcrack density for the faces tested and reduces the degree of fracture damage following thermal shock. The microcrack density is found to be highest in the crystals with (110) face in comparison with the (001) and (111) faces. The effect is analysed using fracture mechanics principles and discussed in terms of the implantation-induced lattice damage