Interaction of carbofuran with the acetylcholinesterase from the brain of the teleost,clarias batrachus

Acetylcholinesterase (EC 3.1.1.7, AChE) of Ciarías batrachus, a fresh water teleost, was localised both in the particulate and soluble fractions of the cell‐free homogenate of the fish brain. The particulate bound enzyme could be solubilised using phosphate buffer containing Triton X‐100 resulting in maximum recovery of enzyme (?98%) in the supernatant. The C. batrachus when exposed to subacute concentrations (0.01 and 0.02 mgL–1) of carbofuran (LC50 ? 0.2 mgL–1) for varying incubation periods, the pesticide caused drastic changes in activity of AChE and protein content in fish brain tissues. Carbofuran exerted inhibitory effect on AChE activity from the brain of C. batrachus. It also caused decrease in the level of fish brain protein. The decrease in AChE activity was maximum when the fish was exposed for 30 days with higher carbofuran concentration (0.02 mgL–1), whereas the decrease in brain protein content was maximum when the fish was exposed for 15 days with same concentration of carbofuran. However, after 30 days of incubation of the fish in the presence of carbofuran, the protein contents were recorded to be sufficiently recovered. The fish brain showed two isozymes of AChE moving far apart from each other on polyacrylamide gel. The intensity of AChE bands however, decreased in the pesticide treated fish showing toxic effect of carbofuran at low concentration.