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Stress Adaptation (stress + adaptation)
Selected AbstractsCloning and sequence analysis of cnaA gene encoding the catalytic subunit of calcineurin from Aspergillus oryzaeFEMS MICROBIOLOGY LETTERS, Issue 1 2001Praveen Rao Juvvadi Abstract Calcineurin has been implicated in ion-homeostasis, stress adaptation in yeast and for hyphal growth in filamentous fungi. Genomic DNA and cDNA encoding the catalytic subunit of calcineurin (cnaA) were isolated from Aspergillus oryzae. The cnaA open reading frame extended to 1727 bp and encoded a putative protein of 514 amino acids. Comparative analysis of the nucleotide sequence of cnaA genomic DNA and cDNA confirmed the presence of three introns and a highly conserved calmodulin binding domain. The deduced amino acid sequence was homologous to calcineurin A from Aspergillus nidulans (92%), Neurospora crassa (84%), human (67%), Saccharomyces cerevisiae (58%) and Schizosaccharomyces pombe (54%). Further, A. oryzae cnaA cDNA complemented S. cerevisiae calcineurin disruptant strain (,cmp1,cmp2), which was not viable in the presence of high concentrations of NaCl (1.2 M) and at alkaline pH 8.5. [source] Transcriptional profiling of the Candida albicans Ssk1p receiver domain point mutants and their virulenceFEMS YEAST RESEARCH, Issue 5 2008Veena Menon Abstract The Ssk1p response regulator of Candida albicans is required for oxidant adaptation, survival in human neutrophils, and virulence in a disseminated murine model of candidiasis. We have previously shown that the amino acid residues D556 and D513 of the Ssk1p receiver domain are critical to the Ssk1p in oxidant stress adaptation and morphogenesis. Herein, transcriptional profiling is used to explain the oxidant sensitivity and morphogenesis defect of two point mutants (D556N and D513K, respectively) compared with a WT strain. In the D556N mutant, during oxidative stress (5 mM H2O2), a downregulation of genes associated with redox homeostasis and oxidative stress occurred, which accounted for about 5% of all gene changes, including among others, SOD1 (superoxide dismutase), CAP1 (required for some types of oxidant stress), and three genes encoding glutathione biosynthesis proteins (GLR1, GSH1, and GSH2). Mutant D513K was not sensitive to peroxide but was impaired in its yeast $/to hyphal transition. We noted downregulation of genes associated with morphogenesis and cell elongation. Virulence of each mutant was also evaluated in a rat vaginitis model of candidiasis. Clearance of an SSK1 null and the D556N mutants from the vaginal canal was significantly greater than wild type or the D513K mutant, indicating that a change in a single amino acid of the Ssk1p alters the ability of this strain to colonize the rat vaginal mucosa. [source] Violence exposure in home and community: Influence on posttraumatic stress symptoms in Army recruits,JOURNAL OF COMMUNITY PSYCHOLOGY, Issue 5 2004Mark G. Chapin This study assessed the levels and types of violence exposure, levels of posttraumatic stress symptoms, and the relationship among exposure to violence, posttraumatic stress symptoms, and early discharge in U.S. Army recruits at Basic Combat Training (BCT). The study applied a modified ABCX model of family stress adaptation developed by McCubbin, Thompson, and McCubbin (1996). A sample of 779 BCT recruits were surveyed before training began. At the end of training, data was collected on those recruits who had been discharged before completion of training. Statistical measures of association were used to assess the relationship between the variables. Results supported all three of the hypotheses tested. Significant positive relationships were found between violence exposure and trauma symptoms, as well as levels of trauma symptoms and odds of early discharge. Patterns of association were found between types of exposure to community versus home violence and specific symptom clusters of traumatic stress. © 2004 Wiley Periodicals, Inc. J Comm Psychol 32: 527,541, 2004. [source] Abscisic Acid-mediated Epigenetic Processes in Plant Development and Stress ResponsesJOURNAL OF INTEGRATIVE PLANT BIOLOGY, Issue 10 2008Viswanathan Chinnusamy Abstract Abscisic acid (ABA) regulates diverse plant processes, growth and development under non-stress conditions and plays a pivotal role in abiotic stress tolerance. Although ABA-regulated genetic processes are well known, recent discoveries reveal that epigenetic processes are an integral part of ABA-regulated processes. Epigenetic mechanisms, namely, histone modifications and cytosine DNA methylation-induced modification of genome give rise to epigenomes, which add diversity and complexity to the genome of organisms. Histone monoubiquitination appears to regulate ABA levels in developing seeds through histone H2B monoubiquitination. ABA and H2B ubiquitination dependent chromatin remodeling regulate seed dormancy. Transcription factor networks necessary for seed maturation are repressed by histone deacetylases (HDACs)-dependent and PICKLE chromatin remodeling complexes (CRCs), whereas ABA induces the expression of these genes directly or through repression of HDACs. Abiotic stress-induced ABA regulates stomatal response and stress-responsive gene expression through HDACs and HOS15-dependent histone deacetylation, as well as through the ATP-dependent SWITCH/SUCROSE NONFERMENTING CRC. ABA also probably regulates the abiotic stress response through DNA methylation and short interfering RNA pathways. Further studies on ABA-regulated epigenome will be of immense use to understand the plant development, stress adaptation and stress memory. [source] Systemin-dependent salinity tolerance in tomato: evidence of specific convergence of abiotic and biotic stress responsesPHYSIOLOGIA PLANTARUM, Issue 1 2010Francesco Orsini Plants have evolved complex mechanisms to perceive environmental cues and develop appropriate and coordinated responses to abiotic and biotic stresses. Considerable progress has been made towards a better understanding of the molecular mechanisms of plant response to a single stress. However, the existence of cross-tolerance to different stressors has proved to have great relevance in the control and regulation of organismal adaptation. Evidence for the involvement of the signal peptide systemin and jasmonic acid in wound-induced salt stress adaptation in tomato has been provided. To further unravel the functional link between plant responses to salt stress and mechanical damage, transgenic tomato (Lycopersicon esculentum Mill.) plants constitutively expressing the prosystemin cDNA have been exposed to a moderate salt stress. Prosystemin over-expression caused a reduction in stomatal conductance. However, in response to salt stress, prosystemin transgenic plants maintained a higher stomatal conductance compared with the wild-type control. Leaf concentrations of abscissic acid (ABA) and proline were lower in stressed transgenic plants compared with their wild-type control, implying that either the former perceived a less stressful environment or they adapted more efficiently to it. Consistently, under salt stress, transgenic plants produced a higher biomass, indicating that a constitutive activation of wound responses is advantageous in saline environment. Comparative gene expression profiling of stress-induced genes suggested that the partial stomatal closure was not mediated by ABA and/or components of the ABA signal transduction pathway. Possible cross-talks between genes involved in wounding and osmotic stress adaptation pathways in tomato are discussed. [source] Banana (Musa spp.) as a model to study the meristem proteome: Acclimation to osmotic stressPROTEINS: STRUCTURE, FUNCTION AND BIOINFORMATICS, Issue 1 2007Sebastien C. Carpentier Abstract Banana (Musa spp.) multiple shoot meristems are an excellent model to study the meristem proteome. Using a 2-DE protocol developed for small amounts of tissue and MS-based cross species polypeptide identification, we have revealed the meristem proteome and investigated the influence of sucrose-mediated osmotic stress in a dehydration-tolerant variety. Proteins that were significantly up- or down-regulated due to the high-sucrose treatment were classified using non-parametric univariate statistics. Our results suggest that the maintenance of an osmoprotective intracellular sucrose concentration, the enhanced expression of particular genes of the energy-conserving glycolysis and the conservation of the cell wall integrity are essential to maintain homeostasis, to acclimate and to survive dehydration. By comparing the dehydration-tolerant variety with a dehydration-sensitive variety, we were able to distinguish several genotype-specific proteins (isoforms), and could associate the dehydration-tolerant variety with proteins involved in energy metabolism (e.g., phosphoglycerate kinase, phosphoglucomutase, UDP-glucose pyrophosphorylase) and proteins that are associated with stress adaptation (e.g., OSR40-like protein, abscisic stress ripening protein-like protein). This work shows that proteome analysis can be used successfully to perform quantitative difference analysis and to characterize genetic variations in a recalcitrant crop. [source] The DDF1 transcriptional activator upregulates expression of a gibberellin-deactivating gene, GA2ox7, under high-salinity stress in ArabidopsisTHE PLANT JOURNAL, Issue 4 2008Hiroshi Magome Summary High-salinity stress affects plant growth and development. We have previously reported that overexpression of the salinity-responsive DWARF AND DELAYED FLOWERING 1 (DDF1) gene, encoding an AP2 transcription factor of the DREB1/CBF subfamily, causes dwarfism mainly by levels of reducing bioactive gibberellin (GA) in transgenic Arabidopsis. Here, we found that the GA 2-oxidase 7 gene (GA2ox7), which encodes a C20 -GA deactivation enzyme, is strongly upregulated in DDF1 -overexpressing transgenic plants. A loss-of-function mutation of GA2ox7 (ga2ox7-2) suppressed the dwarf phenotype of DDF1 -overexpressing plants, indicating that their GA deficiency is due to overexpression of GA2ox7. Transient overexpression of DDF1 activated the promoter of GA2ox7 in Arabidopsis leaves. A gel shift assay showed that DDF1 binds DRE-like motifs (GCCGAC and ATCGAC) in the GA2ox7 promoter. In Arabidopsis under high-salinity stress, six GA2ox genes, including GA2ox7, were upregulated. Furthermore, the ga2ox7-2 mutant was less growth retarded than wild-type Col under high-salinity stress. These results demonstrate that, under salinity stress, Arabidopsis plants actively reduce endogenous GA levels via the induction of GA 2-oxidase, with the result that growth is repressed for stress adaptation. [source] Heat shock proteins as emerging therapeutic targetsBRITISH JOURNAL OF PHARMACOLOGY, Issue 6 2005Csaba Sőti Chaperones (stress proteins) are essential proteins to help the formation and maintenance of the proper conformation of other proteins and to promote cell survival after a large variety of environmental stresses. Therefore, normal chaperone function is a key factor for endogenous stress adaptation of several tissues. However, altered chaperone function has been associated with the development of several diseases; therefore, modulators of chaperone activities became a new and emerging field of drug development. Inhibition of the 90 kDa heat shock protein (Hsp)90 recently emerged as a very promising tool to combat various forms of cancer. On the other hand, the induction of the 70 kDa Hsp70 has been proved to be an efficient help in the recovery from a large number of diseases, such as, for example, ischemic heart disease, diabetes and neurodegeneration. Development of membrane-interacting drugs to modify specific membrane domains, thereby modulating heat shock response, may be of considerable therapeutic benefit as well. In this review, we give an overview of the therapeutic approaches and list some of the key questions of drug development in this novel and promising therapeutic approach. British Journal of Pharmacology (2005) 146, 769,780. doi:10.1038/sj.bjp.0706396 [source] | ||||||||||||||||||||||