球形芽孢杆菌C3—41菌株感染致倦库蚊幼虫的组织病理学研究

HISTOPATHOLOGICAL STUDY OF CULEX PIPIENS QUINQUEFAS- CIATUS LARVAE TREATED WITH BACILLUS SPHAERICUS STRAIN C_(3)-41

The histopathological changes in the midgut of Culex pipiens quinquefaidants larvae trea-ted with Bacillus sphaericus strain C8-41 were observed with light and electron microscopes. The results showed that the epithelial cells of the midgut swelled, sloughed and disrupted sub-sequently, but the basement membrane of the cells and the peritrophic membrane remained in-tact. When the epithelial cells of the mid-gut were disrupted, the cells of caeca were also da-maged. The lysosomes in the epithelial cells increased in quantity and size three hours after infection, and the mitochondria were affected after six hours, including dilation of cristae, in-creasing electron density and subsequently leading to destruction. In the meantime, the endo-plasmic reticula swelled or disrupted, and the basal infolding of the basement membrane ex-panded to form vacuoles. Lesions appeared later in the skeletal muscles. The mechanism of larvicidal action of Bacillus sphaericus toxin is discussed.