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THERMAL STRESS INDUCES HSP 70 PROTEINS SYNTHESIS IN LARVAE OF THE COLD STREAM NON‐BITING MIDGE D iamesa cinerella M eigen
Author(s) -
Lencioni Valeria,
Bernabò Paola,
Cesari Michele,
Rebecchi Lorena,
Cesari Michele
Publication year - 2013
Publication title -
archives of insect biochemistry and physiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.576
H-Index - 66
eISSN - 1520-6327
pISSN - 0739-4462
DOI - 10.1002/arch.21088
Subject(s) - midge , biology , hsp70 , larva , chironomidae , heat shock protein , environmental factor , ecology , genetics , gene
Laboratory experiments on the cold stenothermal midge D iamesa cinerella ( D iptera, C hironomidae) were performed to study the relationship between increasing temperature and heat shock proteins ( HSP 70) expression at translational level ( W estern blotting). Thermotolerance of IV instar larvae collected in nature at 1.5–4.3°C during seasons was analyzed through short‐term (1 h at ten different temperatures from 26°C to 35°C) and long‐term (1–14 h at 26°C and 1–4 h at 32°C) heat shocks. A high thermotolerance was detected ( LT 50 = 30.9–32.8°C and LT 100 = 34.0–37.8°C). However, survival decreased consistently with increasing exposure time, especially at higher temperature ( LT ime 50 = 7.64 h at 26°C and LT ime 50 = 1.73 h at 32°C). The relationship between such heat resistance and HSP 70 expression appeared evident because a relationship between HSP 70 level and larval survival rate was generally found. A heat shock response ( HSR ) was consistent only in the summer larvae. The absence of HSR in the other populations coupled with even higher amounts of HSP 70 than in summer, led us to hypothesize that other macromolecules and other adaptive mechanisms, apart from biochemical ones, are involved in the response of D . cinerella larvae to high temperature. Altogether these results stressed how in this midge the HSP 70 protein family confers resistance against cold, being detected under natural conditions in control larvae collected in all seasons, but also against warm under experimental heat shocks. These results give new insights into possible responses to climate changes in freshwater insects within the context of global warming.