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)

The molecular basis of short term cold resistance (indexed as chill-coma recovery time) has been mostly addressed in D. melanogaster, where candidate genes (Dca (also known as smp-30) and Frost (Fst)) have been identified. Nevertheless, in Drosophila, the ability to tolerate short term exposure to low temperatures evolved several times independently. Therefore, it is unclear whether variation in the same candidate genes is also responsible for short term cold resistance in distantly related Drosophila species. It should be noted that Dca is a candidate gene for cold resistance in the Sophophora subgenus only, since there is no orthologous gene copy in the Drosophila subgenus. Here we show that, in D. americana (Drosophila subgenus), there is a north-south gradient for a variant at the 5' non-coding region of regucalcin (a Dca-like gene; in D. melanogaster the proteins encoded by the two genes share 71.9% amino acid identities) but in our D. americana F2 association experiment there is no association between this polymorphism and chill-coma recovery times. Moreover, we found no convincing evidence that this gene is up-regulated after cold shock in both D. americana and D. melanogaster. Size variation in the Fst PEST domain (putatively involved in rapid protein degradation) is observed when comparing distantly related Drosophila species, and is associated with short term cold resistance differences in D. americana. Nevertheless, this effect is likely through body size variation. Moreover, we show that, even at two hours after cold shock, when up-regulation of this gene is maximal in D. melanogaster (about 48 fold expression change), in D. americana this gene is only moderately up-regulated (about 3 fold expression change). Our work thus shows that there are important differences regarding the molecular basis of cold resistance in distantly related Drosophila species.
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PMID:A comparative study of the short term cold resistance response in distantly related Drosophila species: the role of regucalcin and frost. 2199 16

Temperature-induced plasticity of cold tolerance has been reported in many insect species, but cold tolerance can also be affected by changes in day (or night) length. In the present study we elucidate the direct and indirect effects of photoperiod on the cold tolerance of females of two Drosophila montana strains--one which possesses a robust photoperiodic diapause and another which does not. In the diapause-strain the time needed for recovery from chill coma showed a positive correlation with day length, but diapause itself played only a minor role in photoperiodic acclimation. The strain that was not able to enter to diapause as a response to day length also lacked photoperiodic cold acclimation ability indicating that this strain has deficiencies in its photoperiodic time measurement system. In the diapause-strain, the expression level of regucalcin gene was more than two times higher in diapausing than in non-diapausing females maintained in a single photoperiod, but day length per se did not cause significant changes in expression levels of this gene in either of the strains. In the non-diapausing strain this gene showed no expression changes in any comparison. Overall, the study shows that a decrease in day length can induce cold acclimation in D. montana, while changes in regucalcin expression are linked with photoperiodic diapause.
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PMID:Photoperiodic regulation of cold tolerance and expression levels of regucalcin gene in Drosophila montana. 2236 Sep 99