Project description:The ability to rapidly respond to changes in temperature is critical for insects and other ectotherms living in variable environments. In a physiological process termed rapid cold-hardening (RCH), exposure to non-lethal low temperature allows many insects to significantly increase their cold tolerance in a matter of minutes to hours. Additionally, there are rapid changes in gene expression and cell physiology during recovery from cold injury, and we hypothesize that RCH may modulate some of these processes during recovery. In this study, we used a cDNA microarray to examine the molecular mechanisms of RCH and cold shock (CS) recovery in the flesh fly, Sarcophaga bullata. With our custom 2-color array, we measured expression of ~15,000 ESTs during RCH and during recovery from cold shock. Surprisingly, no transcripts were upregulated during RCH, and likewise, RCH had a minimal effect on the transcript signature during recovery from cold shock. However, during recovery from cold shock, we observed differential expression of ~1,400 ESTs, including a number of heat shock proteins, cytoskeletal components, and genes from several cell signaling pathways. Several gene pathways correlated well with metabolomics data, indicating that coordinated changes in gene expression and metabolism contribute to recovery from cold shock.
Project description:The ability to rapidly respond to changes in temperature is critical for insects and other ectotherms living in variable environments. In a physiological process termed rapid cold-hardening (RCH), exposure to non-lethal low temperature allows many insects to significantly increase their cold tolerance in a matter of minutes to hours. Additionally, there are rapid changes in gene expression and cell physiology during recovery from cold injury, and we hypothesize that RCH may modulate some of these processes during recovery. In this study, we used a cDNA microarray to examine the molecular mechanisms of RCH and cold shock (CS) recovery in the flesh fly, Sarcophaga bullata. With our custom 2-color array, we measured expression of ~15,000 ESTs during RCH and during recovery from cold shock. Surprisingly, no transcripts were upregulated during RCH, and likewise, RCH had a minimal effect on the transcript signature during recovery from cold shock. However, during recovery from cold shock, we observed differential expression of ~1,400 ESTs, including a number of heat shock proteins, cytoskeletal components, and genes from several cell signaling pathways. Several gene pathways correlated well with metabolomics data, indicating that coordinated changes in gene expression and metabolism contribute to recovery from cold shock. Four treatment groups (C, RCH, CS+2R, RCH+CS+2R), four biological replicates of four pooled individuals for each treatment. Each phenotype was hybridized with the control, and the CS+2R and RCH+CS+2R groups were also hybridized together.
Project description:The biochemical and molecular mechanisms of insect cold acclimation prior to cold stress have been relatively well explored. The mechanisms linked to recovery and repair after cold stress received much less attention.Here we focus on recovery from cold stress in the larvae of vinegar fly (Drosophila melanogaster) that were exposed to two physiologically distinct cold stress situations; supercooling (S, survival > 90%) and freezing (F, survival < 10%), both at -5°C.The transcriptomic responses to cold stress were analyzed.