Project description:To understand plant adaptation to heat stress, gene expression profiles of Arabidopsis leaves under heat stress, during recovery and control condition were obtained using microarray. Microarray data listed responsible candidate genes for glycerolipid metabolism.
Project description:Background: Geographic variation in the thermal environment impacts a broad range of biochemical and physiological processes and can be a major selective force leading to local population adaptation. In the intertidal copepod Tigriopus californicus, populations along the coast of California show differences in thermal tolerance that are consistent with adaptation, i.e., southern populations withstand thermal stresses that are lethal to northern populations. To understand the genetic basis of these physiological differences, we use an RNA-seq approach to compare genome-wide patterns of gene expression in two populations known to differ in thermal tolerance. Results: Observed differences in gene expression between the southern (San Diego) and the northern (Santa Cruz) populations included both the number of affected loci as well as the identity of these loci. However, the most pronounced differences concerned the amplitude of up-regulation of genes producing heat shock proteins (Hsps) and genes involved in ubiquitination and proteolysis. Cuticle genes were up-regulated in SD but down-regulated in SC, and mitochondrial genes were downregulated in both populations. Among the hsp genes, orthologous pairs show markedly different thermal responses as the amplitude of hsp response was greatly elevated in the San Diego population, most notably in members of the hsp70 gene family. There was no evidence of accelerated evolution at the sequence level for hsp genes. Conclusions: Marked changes in gene expression were observed in response to acute sublethal thermal stress in the copepod T. californicus. Although some qualitative differences were observed between populations (e.g., cuticle gene regulation), the most pronounced differences involved the magnitude of induction of numerous hsp and ubiquitin genes. These differences in gene expression suggest that evolutionary divergence in the regulatory pathway(s) involved in acute temperature stress may offer at least a partial explanation of latitudinal trends in thermal tolerance observed in Tigriopus. For each population, ~600 copepods were split into two equal samples, one for control and one for treatment. Each sample was placed in a 50 mL Falcon tube containing 30 mL filtered seawater. After equilibrating samples to 20 degrees C, each tube was immersed in water bath at its target temperature (control: 20 C; treatment: 35 C) for one hour, and then immersed at 20 C for one hour for recovery. Copepods were then collected in a net mesh and quickly transferred to a tube containing 5 mL Tri-reagent for standard RNA extraction.
Project description:We conducted a set of lab-evolution experiments in yeast and followed the long-term dynamics of aneuploidy under diverse conditions including heat shock and high PH. Each evolution experiment starts with an ancestor strain that was subjected (in several independent repetitions) to certain growth conditions such as high temperature 39°C, permissive temperature 30°C, gradually increasing temperature from 30°C to 39°C, high pH=8.6 and normal PH. In all cases the mRNA extraction was performed on a population sample that was grown for 18 generations under stress-less conditions. This is since we aimed to measure the gene expression changes that are due to stress adaptation and not the physiological response.
Project description:To ensure cell survival and growth during temperature increase, eukaryotic organisms respond with transcriptional activation that results in accumulation of proteins that protect against damage, and facilitate recovery. To define the global cellular adaptation response to heat stress, we performed a systematic genetic screen that yielded 277 yeast genes required for growth at high temperature. Of these, the Rpd3 histone deacetylase complex was enriched. Global gene expression analysis showed that Rpd3 partially regulated gene expression upon heat shock. The Hsf1 and Msn2/4 transcription factors are the main regulators of gene activation in response to heat stress. RPD3-deficient cells had impaired activation of Msn2/4-dependent genes, while activation of genes controlled by Hsf1 was deacetylase independent. Rpd3 bound to heat stress-dependent promoters through the Msn2/4 transcription factors, allowing entry of RNA Pol II and activation of transcription upon stress. Finally, we found that the large, but not the small Rpd3 complex regulated cell adaptation in response to heat stress.
Project description:Dental caries are closely associated with the virulence of Streptococcus mutans. The virulence expression of S. mutans is linked to its stress adaptation to the changes in the oral environment. In this work we used whole-genome microarrays to profile the dynamic transcriptomic responses of S. mutans during physiological heat stress. In addition, we evaluated the phenotypic changes, including initial biofilm formation, acid production and ATP turnover of S. mutans during heat stress. There were distinct patterns observed in the way that S. mutans responded to heat stress that included 66 transcription factors for the expression of functional genes being differentially expressed. Especially, response regulators of two component systems (TCSs), the repressors of heat shock proteins and regulators involved in sugar transporting and metabolism co-ordinated to enhance the cell’s survival and energy generation against heat stress in S. mutans.
Project description:To ensure cell survival and growth during temperature increase, eukaryotic organisms respond with transcriptional activation that results in accumulation of proteins that protect against damage, and facilitate recovery. To define the global cellular adaptation response to heat stress, we performed a systematic genetic screen that yielded 277 yeast genes required for growth at high temperature. Of these, the Rpd3 histone deacetylase complex was enriched. Global gene expression analysis showed that Rpd3 partially regulated gene expression upon heat shock. The Hsf1 and Msn2/4 transcription factors are the main regulators of gene activation in response to heat stress. RPD3-deficient cells had impaired activation of Msn2/4-dependent genes, while activation of genes controlled by Hsf1 was deacetylase independent. Rpd3 bound to heat stress-dependent promoters through the Msn2/4 transcription factors, allowing entry of RNA Pol II and activation of transcription upon stress. Finally, we found that the large, but not the small Rpd3 complex regulated cell adaptation in response to heat stress. Three independent 200 ml cultures of wild-type and rpd3Δ mutant strains were grown to mid-log phase in YPD rich medium at 25ºC (control) or at 39 ºC for 20 min (heat stressed). Results were analyzed comparing thermo-responsive gene expression respect to the control in each individual strain.
Project description:Exploration of heat stress induced genes in granulosa cells is critical to characterization of candidate genes for thermal stress research in pigs. This study aimed to gain insight into the differentially expressed genes (DEGs) and signalling pathways regulating porcine granulosa cell adaptation to in vitro heat stress challenge at 42OC for 6 hours. Transcriptome profiling of heat stressed (treated) and non-heat stressed (control) granulosa cells was conducted using Illumina NextSeq2000 sequencing platform. The significant DEGs were selected using NOISeq R package with cut-offs, probability value ≥ 0.95 and absolute log2(fold change) ≥1. Bioinformatics analysis of DEGs were conducted to explore functional annotations enrichment, protein-protein interaction network and hub genes regulating the cellular homeostasis and survivability during heat stress challenge.
2024-10-22 | GSE243234 | GEO
Project description:Genome dynamics and temperature adaptation during experimental evolution of obligate intracellular bacteria
Project description:To understand faster reinduction of heat acclimation, in this investigation we studied global stress associated genomic response during acclimation, following its loss and re-induction. Nylon cDNA Atlas Array was used. Collectively, the study comprised nine experimental groups of which six characterized experimental basal conditions: Controls-untreated, Short and Long term heat acclimated groups ( exposure to environmental heat at 34oC for 2 or 30 days respectively), Deacclimated group (24oC for 1mo) and Reacclimated groups (2d at 34oC following the deacclimation protocol). Three additional experimental groups: Controls, Short and Long term and Reacclimated rats (as above) were tested for genomic responses following subjection to heat stress at 41oC. Because of a dichotomy between genomic and physiological responses we hypothesize thst rapid reacclimation is linked to reprograming of gene expression. Keywords: heart, Left ventricle