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Effect of Three Chlorinated Pesticides on hsrω Stress gene in Transgenic Drosophila melanogaster
Author(s) -
Chowdhuri D. Kar,
Nazir Aamir,
Saxena D. K.
Publication year - 2001
Publication title -
journal of biochemical and molecular toxicology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.526
H-Index - 58
eISSN - 1099-0461
pISSN - 1095-6670
DOI - 10.1002/jbt.15
Subject(s) - endosulfan , biology , microbiology and biotechnology , trypan blue , gene expression , drosophila melanogaster , polytene chromosome , staining , gene , pesticide , biochemistry , cell culture , genetics , agronomy
Expression of hsrω stress gene in the third‐instar larvae of 951‐lacZ2( hsrω‐lacZ having–844pb sequence) and 498‐lacZ1( hrsω‐lacZ having –498bp sequence) strains of Drosophila melanogaster at LC 50 and lower dietary concentrations of hexachlorocyclohexane (HCH) pentachlorophenol(PCP), and endosulfan was examined in relation to larval mortality by β galactosidase activity,vital dye staining, and salivary gland polytene chromosome puffing. Our results showed that both HCH and PCP atlower concentrations evoked strong hsrω stress gene expression in the larval tissues whileendosulfan did not. On the other hand, puffing data revealed that endosulfan at lower doses, inducedwell‐developed puff at the resident site (93D) of the hsrω gene but the transgenicsites (30B in 951‐lacZ2 and 44B in 498‐lacZ1 strain) did not show anywell‐developed puff. Regression in hsrω stress gene expression in 951‐lacZ2 strain atLC 50 concentrations of HCH and PCP after 48 h was concurrent with extensive tissue damage as evidentby trypan blue staining. Similarly, strong hsrω expression was accompanied by insignificant trypanblue staining in the larval tissues of this strain after shorter duration of exposure (2–12 h)to these toxicants. Although endosulfan under similar experimental condition did not induce hsrω ,strong trypan blue staining indicated extensive tissue damage after 48 h of exposure. The present study suggeststhat all the three toxicants pose cytotoxic potential to Drosophila . While protective role of this stressgene was evident at the initial stages of exposure, extensive tissue damage in the later stages of intoxicationaccompanied by autorepression of hsrω led to larval mortality. The study further suggests that–844bp upstream sequence of the gene is adequate for hsrω inducibility against HCH and PCPbut not for endosulfan for which responsive elements may be searched further upstream. © 2001 John Wiley& Sons, Inc. J Biochem Mol Toxicol 15:173–186, 2001