Project description:Temperature has fundamental influences on fitness and distribution of insects. There have been very few studies on effects of mild cold conditions on insects. We found Plutella xylostella had reduced fitness and females produced few viable eggs when reared at 10°C, a temperature at which they can complete development. Male moths reared at 10°C were not able to fertilize eggs, but the eggs produced by female moths reared at this temperature were viable and could be fertilisied by males moths reared at a warmer temperature (25°C). Subsequently, we examined the transcriptomic changes in mid-fourth instar female and male larvae reared at 10°C and 25°C to investigate sex-dependent developmental and physiological responses of P. xylostella to the mild cold stress. We found 624 differentially expressed genes (DEGs) in females, the majority of which were down-regulated. In males 3239 genes were dysregulated and the majority were up-regulated. Only 280 DEGs were common to both sexes. In females, no DEGs encoded heat shock or cold shock proteins, but some of the DEGs in males did encode these proteins. These differences might suggest that female and male adopt some different strategies in coping with cold stress and/or they were passively affected by coldness to different degrees and in different ways. In addition, DEGs encoding antimicrobial peptides, cytochrome P450 monooxygenases, fatty acid-related enzymes, cuticle proteins, myofilament, and hormone-related proteins were found in both sexes under cold stress. The transcriptome study reveals unexpected sex-dependent thermal responses and provides much new information of how insects that do not diapause cope with a decreased temperature
Project description:Whole-genome analysis of heat shock factor binding sites in Drosophila melanogaster. Heat shock factor IP DNA from non-shock (room temperature) Kc 167 cells compared to whole cell extract on Agilent 2x244k tiling arrays.
Project description:Expression analysis of Heat Shock in Drosophila melanogaster KC167 Cells and 3rd instar dpcnbw larvae, and room temperature expression levels using Nimblegen arrrays (GPL8443) A 12 chip study using total RNA recovered from Heat shocked or non-heat shocked (room temperature) samples in either cells or larvae, 3 technical replicates for each treatment
Project description:Time series of eleven breast cancer samples subjected to different cold ischemic stress of up to 3 hr post tumor excision. A different 2x2 factorial within this study evaluated the effect of stabilization method (RNAlater vs snap freezing) and stablization delay (0 and 40 min) at room temperature.
Project description:A transcriptome analysis was applied on two peach (Prunus persica L.) cultivars with different sensitivity to low temperature regimes to identify cold-responsive genes that might be involved in tolerance to long low temperature storage. Peach fruit from ‘Morettini No2’ and ‘Royal Glory’, a sensitive and a tolerant, to chilling injury cultivars, respectively, were harvested at commercial maturity stage and allowed to ripen at room temperature (25°C) or subjected to 4 and 6-weeks of cold storage (0°C, 95% R.H.) followed by ripening at room temperature. Microarray experiments, employing the peach microarray platform (μ PEACH 1.0), were carried out by comparing harvested fruit against 4- and 6-week cold-stored fruit. The analysis identified 173 and 313 genes that were differentially expressed in ‘Morettini No2’ and ‘Royal Glory’ fruit after 4 weeks, respectively. However, the 6 weeks cold storage provoked a decrease in the total number of genes differentially expressed in both cultivars. RNA blot analysis validated the differential expression of certain genes showed in microarray data. Among these genes, two heat shock proteins (hsps), a putative β-D-xylosidase, an expansin, a dehydrin and a pathogenesis-related protein PR-4B precursor were induced during cold storage in both cultivars. The induction of hsps and the putative β-D-xylosidase appeared to be independent on the duration of postharvest treatment. On the other hand, transcript levels of lipoxygenase were quite constant during postharvest ripening, while a strong reduction or disappearance was observed after cold storage. A dehydration-induced RD22-like protein showed a reduction in the accumulation of transcripts during postharvest ripening independently on the temperature conditions. Overall, the current study shed some light on the molecular aspects of cold stress in peach fruit quality and identified some ripening and/or cold-induced genes which function need further elucidation.
Project description:Transcriptome analysis may provide means to investigate the underlying genetic causes of shared and divergent phenotypes in different populations and help to identify potential targets of adaptive evolution. Applying RNA sequencing to whole male Drosophila melanogaster from the ancestral tropical African environment and a very recently colonized cold-temperate European environment at both standard laboratory conditions and following a cold shock, we seek to uncover the transcriptional basis of cold adaptation. In both the ancestral and the derived populations, the predominant characteristic of the cold shock response is the swift and massive upregulation of heat shock proteins and other chaperones. Although we find ~30% of the genome to be differentially expressed following a cold shock, only relatively few genes (n=26) are up- or down-regulated in a population-specific way. Intriguingly, 24 of these 26 genes show a greater degree of differential expression in the African population. Likewise, there is an excess of genes with particularly strong cold-induced changes in expression in Africa on a genome-wide scale. The analysis of the transcriptional cold shock response most prominently reveals an upregulation of components of a general stress response, which is conserved over many taxa and triggered by a plethora of stressors. Despite the overall response being fairly similar in both populations, there is a definite excess of genes with a strong cold-induced fold-change in Africa. This is consistent with a detrimental deregulation or an overshooting stress response. Thus, the canalization of European gene expression might be responsible for the increased cold tolerance of European flies.