Project description:Arctic Mesorhizobium strain N33 was isolated from nodules of the Oxytropis arctobia in Canada’s eastern Arctic. This symbiotic bacterium can grow from 0 to 30°C, is one of the best known cold-adapted rhizobia, and can fix nitrogen at ~10°C. Here, the key molecular mechanisms of cold adaptation were investigated by determining changes in transcript profiles when cells were treated under eight different temperature conditions, including both sustained and transient cold treatments compared with cells grown at room temperature.
Project description:The mechanisms that allow psychrophilic bacteria to remain metabolically active at subzero temperatures result from form and function of their proteins. We present first proteomic evidence of physiological changes of the marine psychrophile Colwellia psychrerythraea 34H (Cp34H) after exposure to subzero temperatures (-1, and -10°C in ice) through 8 weeks. Protein abundance was compared between different treatments to understand the effects of temperature and time, independently and jointly, within cells transitioning to, and being maintained in ice. Parallel [3H]-leucine and [3H]-thymidine incubations indicated active protein and DNA synthesis to -10°C. Mass spectrometry-based proteomics identified 1763 proteins across four experimental treatments. Proteins involved in osmolyte regulation and polymer secretion were found constitutively present across all treatments, suggesting that they are required for metabolic success below 0°C. Differentially abundant protein groups indicated a reallocation of resources from DNA binding to DNA repair and from motility to chemo-taxis and sensing. Changes to iron and nitrogen metabolism, cellular membrane structures, and protein synthesis and folding were also revealed. By elucidating vital strategies during life in ice, this study provides novel insight into the extensive molecular adaptations that occur in cold-adapted marine organisms to sustain cellular function in their habitat. Raw data available at http://www.chorusproject.org Public project ID number 682.
2019-02-15 | PXD006274 | Pride
Project description:Metabolic robustness to growth temperature of cold adapted bacterium
Project description:Transcriptome profiling of leaves of perennial ryegrass genotype Veyo adapted to warmer climates, and ‘Falster’ adapted to cold climates, in response to low-temperature and drought stress conditions, were performed using RNA-Seq approach.
Project description:Stress leads to important adaptive physiological responses including release of catecholamines from the adrenal medulla. Repeated or prolonged stress increases the propensity for many disorders including cardiovascular disease and neuropsychiatric disorders. The susceptibility to stress is determined by a number of factors including prior experience with stress. It has been found that while there is adaptation to prolonged cold stress; it leads to sensitization when cold stressed animals are exposed to a different (novel) stressor. Our study aims to determine the mechanism of this adaptation and sensitization.,We will determine the gene expression patterns in rat adrenal medulla in response to several times of cold stress. We will also determine the changes in gene expression with single immobilization stress in adrenal medulla of rat with and without preexposure to cold stress to investigate the mechanism of sensitization in cold adapted animals. ,We hypothesize that during the course of cold stress there are alterations in gene expression of several neurotransmitter related genes and transcription factors. In cold adapted animals, there is increased susceptibility to stress due to sustained changes in expression of several transcription factors, such as FRA-2 which lead to an exaggerated response to the novel stressor. ,Rats were exposed to cold stress (4oC) for 1, 7 or 28 days. A parallel group was kept at room temperature (unstressed). Unstressed or rats pre-exposed to 28 days cold were immobilized for 2 hrs and killed by decapitation. The adrenal medullae, separately from right and left side, have been dissected and individually frozen at -70oC. Our recent immunoblots with the tissue from one side revealed that there is increase in tyrosine hydroxylase and c-fos with the short term cold stress and in dopamine beta hydroxylase and Fra-2 even with the prolonged cold stress. The response of several transcription factors to immobilization stress was enhanced in the cold adapted animals. RNA will be prepared with RNAqueous-Micro Isolation kit from Ambion (alternatively we can ship the tissues). We will pool samples from 4 rats per treatment to control for variability.
Project description:The goal of this study was to measure the effect of heat stress on the transcriptome of a cold-adapted fish species - Trematomus bernacchii - an Antarctic fish species. Keywords: Stress response