INSECTICIDAL TOXIN OF BACILLUS SPHAERICUS 1593 AND 2362

球形芽孢杆菌是一种芽胞形成细菌，具有高度的 对某些蚊种幼虫的杀虫活性。这 细菌正在被开发为微生物控制剂，用于 集成的矢量控制程序。在近40种杀虫药物中 球形芽孢杆菌目前已知的两个非常相似的菌株，1593和 2362似乎具有最大的潜在实用价值。球形芽孢杆菌 1593通过一种约50千克的蛋白质毒素杀死蚊子幼虫， 它是在产孢期产生的。这种毒素是用一种 伴生晶体，少量存在于孢子本身。喝醉了 幼虫在摄食大型海鲜后1小时内出现肠道和行为症状。 剂量的球形芽孢杆菌，并可能在短短4小时内死亡。 这项提案的目标是开发一种针对B。 利用培养的蚊子细胞产生球形毒素，并利用该方法 研究寄主-病原菌相互作用的参数，包括毒素 激活、结合和分子作用模式，以及 细胞的超微结构变化。毒素将用一种 凝胶和离子交换层析的组合，可能随后 亲和层析或高效液相色谱。单抗和多克隆抗体 提高到毒素将被用于提纯和定位 毒素。

Bacillus sphaericus is a sporeforming bacterium with a high degree of insecticidal activity toward larvae of certain mosquito species. This bacterium is being developed as a microbial control agent for use in integrated vector control programs. Among the nearly 40 insecticidal strains of B. sphaericus currently known two very similar strains, 1593 and 2362, appear to have the greatest potential utility. Bacillus sphaericus 1593 kills mosquito larvae by means of a protein toxin of ca. 50 Kdal, which is produced during sporulation. This toxin is packaged in a parasporal crystal and to a lesser extent in the spore itself. Intoxicated larvae show gut and behavioral symptoms within 1 hr of ingestion of large dose of B. sphaericus, and may die in as little as 4 hr. The objectives of this proposal are to develop an invitro assay for the B. sphaericus toxin utilizing cultured mosquito cells and to use this assay to investigate parameters of the host-pathogen interaction including toxin activation, binding, and molecular mode of action, as well as ultrastructural changes in the cells. Toxin will be purified using a combination of gel and ion exchange chromatography, possibly followed by affinity or HPLC chromatography. Monoclonal and polyclonal antibodies raised to the toxin will be utilized in purification and localization of the toxin.