INSECTICIDAL TOXIN OF BACILLUS SPHAERICUS

球形芽孢杆菌是一种产孢量高的细菌。 作为媒介蚊子的微生物防治剂的潜力。 这种有机体通过一种蛋白质毒素杀死宿主。这个 毒素对幼虫和培养的细胞有很强的杀虫作用 蚊子的种类，但对某些蚊子的毒性要小得多 如埃及伊蚊等物种，对其他昆虫无毒 不仅是蚊子，也不是哺乳动物。这份提案描述了 试图检查这种毒素与 和蚊子幼虫细胞的培养，并探索 在体外和体内都有作用。具有抵抗力的蚊子物种将 与敏感物种进行比较，以确定减少的原因 敏感度。标记的毒素将用于研究结合和 毒素的内化。细胞膜的成分 负责对敏感物种进行绑定的人将被检查， 分离的，并提高到该受体的抗血清将用于 检查抗病物种的蛋白质。单抗将会 被提升到毒素和受体，并将被用于 研究毒素的结合和作用方式。可能的 作用方式，包括膜孔的发育和变化 在环状AMP方面将有所探索。一项超微结构研究将寻求 培养和幼虫中肠细胞的细胞膜变化 与球形芽孢杆菌毒素中毒有关，以及微量 金标毒素在培养细胞和细胞内的运动 幼虫。

Bacillus sphaericus is a sporeforming bacterium with a high degree of potential as a microbial control agent for vector mosquitoes. This organism kills the host by means of a protein toxin. The toxin is highly insecticidal to larvae and cultured cells from many species of mosquitoes, but is much less toxic to certain mosquito species such as Aedes aegypti and is not toxic to insects other than mosquitoes nor to mammals. This proposal describes experiments that seek to examine the binding of this toxin to cultured and mosquito larval cells and to explore the mode of action both in vitro and in vivo. Resistant mosquito species will be compared to sensitive species, to determine the cause of reduced sensitivity. Labelled toxin will be used to study binding and internalization of the toxin. The component of the cell membrane responsible for binding in sensitive species will be examined, isolated, and antiserum raised to this receptor will be used to examine proteins of resistant species. Monoclonal antibodies will be raised to the toxin and the receptor, and will be used to investigate binding and mode of action of the toxin. Possible modes of action including development of membrane pores and changes in cyclic-AMP will be explored. An ultrastructural study will seek changes in the cell membrane of cultured and larval midgut cells associated with intoxication by the B. sphaericus toxin, and trace movement of gold-labelled toxin in cultured cells and in the larvae.