Comparative role of proteins in transport of HCH-isomers in desert locust, Schistocerca gregaria Forskal and bovines.

The studies on binding of hexachlorocyclohexane (HCH) with carrier proteins were carried out to establish the role of proteins in the transport of insecticides in insects. Sephadex G-200 column chromatography resolved haemolymph of adult male desert locust, Schistocerca gregaria into three major protein peaks. There was significant binding of gamma-HCH with first protein peak (F1). Two classes of binding sites were observed on first protein peak for gamma-HCH. However low level of binding was observed with the third protein peak (F3) of the haemolymph. Bindings of HCH-isomers (alpha, beta and gamma) with bovine serum albumin (BSA) were not related to their water solubilities. Moderate to low affinities (1.4 -1.84 x 10(6) M(-1)) of HCH-isomers for BSA were observed. The present studies showed that more HCH binds to haemolymph lipoprotein of locust as compared to BSA. This indicates a significant role of haemolymph proteins in the transport of insecticides in insects.

Normal vibrations and valence charge distribution in relation to bioactivity of gammexane.

Normal coordinate analysis has been made for gammexane using the Wilson's G-F matrix method with Urey-Bradley force field. Molecular orbital calculations using CNDO/2 method have also been carried out for the five isomers of hexachlorocyclohexane to give the valence charge densities on the atoms of the molecules. A toxicity parameter that takes into account a shape factor and the valence charge density on the atoms has been defined. On the toxicity scale so defined the gamma-isomer alone has a significant value.