Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0085593 (chills)
 4,268 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Nutritional deprivation or desiccation can influence thermal tolerance by impacting the insects' ability to evaporatively cool, maintain cell membrane integrity and conduct protective or repair processes. Recovery from chilling is also linked to the re-establishment of iono- and osmo-regulatory homeostasis. Here, using Mediterranean fruit fly (Ceratitis capitata, Diptera: Tephritidae), we manipulated water and nutrient availability to test the mechanistic expectation that changes in whole organism lipid and water content can elicit variation in cold or heat tolerance (scored as chill coma recovery time and heat knockdown time). We measured body condition (body water and lipid content) as well as heat shock protein 70 gene (hsp70) and protein (HSP70) levels. A significant reduction in body water content with water restriction did not translate into differences in chill coma recovery. When nutrient restriction was coupled with water deprivation, this resulted in a significant reduction (-54%) of heat knockdown time in females but male flies were unaffected. There was no evidence for an hsp70 or HSP70 response under any of the stress treatments and therefore no correlation with heat or cold tolerance. Heat hardening decreased all hsp levels. Therefore, although body water and total body lipid content differed between the treatment groups, the contribution of these factors to thermal tolerance was inconsistent with mechanistic expectations in heat knockdown time and insignificant for chill coma recovery. These results therefore highlight that the effects of resource restriction on thermal limits in insects are mechanistically more complex than previous models of stress resistance have suggested.
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PMID:Effects of nutrient and water restriction on thermal tolerance: A test of mechanisms and hypotheses. 2867 79

Cold tolerance, the ability to cope with low temperature stress, is a critical adaptation in thermally variable environments. An individual's cold tolerance comprises several traits including minimum temperatures for growth and activity, ability to survive severe cold, and ability to resume normal function after cold subsides. Across species, these traits are correlated, suggesting they were shaped by shared evolutionary processes or possibly share physiological mechanisms. However, the extent to which cold tolerance traits and their associated mechanisms covary within populations has not been assessed. We measured five cold tolerance traits-critical thermal minimum, chill coma recovery, short- and long-term cold tolerance, and cold-induced changes in locomotor behavior-along with cold-induced expression of two genes with possible roles in cold tolerance (heat shock protein 70 and frost)-across 12 lines of Drosophila melanogaster derived from a single population. We observed significant genetic variation in all traits, but few were correlated across genotypes, and these correlations were sex-specific. Further, cold-induced gene expression varied by genotype, but there was no evidence supporting our hypothesis that cold-hardy lines would have either higher baseline expression or induction of stress genes. These results suggest cold tolerance traits possess unique mechanisms and have the capacity to evolve independently.
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PMID:Distinct cold tolerance traits independently vary across genotypes in Drosophila melanogaster. 3246 18