Impact of Thiovit®Jet Treatment on HSP-70 Expression, as a Stress Indicator, In Transgenic Drosophila melanogaster

Abstract

The present study aims to observe the effects of the fungicide Thiovit Ò Jet on hsp70 expression in third instar larvae of transgenic Bg9 (hsp70-lacZ) strain of Drosophila melanogaster. Various concentrations (40, 50, 200 and 1600 ppm) of Thiovit Ò Jet in distilled water was added to the food medium. A similar set of control experiments were maintained without any chemical treatment (normal food). Third instar larvae were assayed for stress gene expression and found to express hsp70 under treated conditions. Lower doses of treatment elicited positive response in larval skin, parts of midgut and entire hindgut. Higher doses of the treatment and longer hours of exposure gave somewhat lower positive results excepting with 1600 ppm where an increase in expression with increased hour of exposure is found initially followed by a subsequent decline in expression to almost undetectable level. Low dose and short-term exposure of Thiovit Ò Jet is effective to the flies, which are an innocent target. Negative results may be due to lack of viable cells after a certain time of exposure causing unavailability of cells expressing hsp70. Bg9 strain of Drosophila melanogaster used for this study is transgenic with lacZ reporter gene fused with wild type hsp70 gene. The lacZ products confirm the hsp70 expression. Longer hours of exposure may also make reporter gene products unstable, which do not elicit any positive response.