Xenobiotic Induced Expression of Epsilon Glutathione S – Transferases Gste2 In Laboratory Strains of Anopheles Arabiensis

Over expression of GSTe2 has been associated with resistance to DDT in An . arabiensis. The expression of the gene was induced by exposing the fourth instar larvae obtained from KGB and MAT strains to xenobiotic inducers. Transcripts levels of GSTe2 in cDNAs of the larvae from each strain was measured by quantitative PCR at various time points post exposure to DDT, permethrin and hydrogen peroxide. Statistical analysis was used to test for differences and compare the expression of the gene between treatments and mosquito strains. The geometric mean expression levels of GSTe2 induced at one hour by DDT in the KGB was 1.028 (CI 0.901~1.172; p < 100) compared to 0.587 (CI 0.475~0.724; p = 0.025) in MAT strain. Higher induction of GSTe2 in KGB was caused by DDT and hydrogen peroxide and with permethrin and DDT in MAT strain. Further research is needed to understand the molecular mechanisms regulating response of An. arabiensis to xenobitics.