Partial Purification and Characterization of Glutathione S-Transferases Involved in DDT Resistance from the Mosquito Anopheles gambiae

In this study we characterize the involvement of glutathione S-transferase in DDT resistance of the malaria vector, Anopheles gambiae. A comparative study of the seven glutathione S-transferases isolated from a 20-fold DDT-resistant strain and a DDT-susceptible strain of the mosquito was performed using four inhibitors and six substrates. We report that in A. gambiae DDT resistance was apparently conferred by qualitatively different glutathione S-transferases that also appear to be present in higher concentrations. The seven glutathione S-transferases did not immunologically cross-react with Alpha, Mu, or Pi antisera or antiserum against GST-1 from house fly and Drosophila. The results suggest significant differences between the vertebrate and the insect glutathione S-transferases.