CHARACTERIZATION OF MOSQUITO LARVICIDAL PARASPORAL INCLUSIONS OF A BACILLUS-THURINGIENSIS SEROVAR HIGO STRAIN

The parasporal inclusion proteins of the type strain of Bacillus thuri ngiensis serovar higo (H44), that have moderate mosquitocidal activity , were characterized. The purified parasporal inclusions, spherical in shape, were examined for activity against the two mosquito species, C ulex pipiens molestus and Anopheles stephensi and the moth-fly, Telmat oscopus albipunctatus. The LC50 values of the inclusion for the two mo squitoes were 3.41 and 0.15 mu g ml(-1), respectively. No mortality wa s shown for T. albipunctatus larvae by the inclusions at concentration s up to 1 mg ml(-1). Solubilized parasporal inclusions exhibited no ha emolytic activity against sheep erythrocytes. Parasporal inclusions co nsisted of eight proteins with molecular masses of 98, 91, 71, 63, 59, 50, 44 and 27 kDa. Of these, the 50 and 44 kDa proteins were the majo r components. Analysis with immunoblotting revealed that, among severa l inclusion proteins of B. thuringiensis serovar israelensis, only two proteins of 130 kDa and 110 kDa reacted weakly with antibodies agains t higo proteins. N-terminal amino acid sequences of the 98, 91, and 71 kDa proteins showed 85-100% identity to those of the two established Cry protein classes, Cry4A and Cry10A.