Significance of Exosporium Enclosure of Parasporal Inclusions of Bacillus thuringiensis

苏云金芽孢杆菌是一种革兰氏阳性产孢细菌 产生大量的孢子形成特异性蛋白质。 这些蛋白质以伴孢内含物的形式积累， 对昆虫幼虫有选择活性的原毒素。 一般而言， 内含物沉积在孢子外壁外， 与孢子分开进入环境 在亚种中 finitimus，然而，内含物和孢子有共同的 外孢壁，并一起释放。 孢子外壁 比孢子疏水（Koshikawa等人，1989），和外孢 封闭的内含物比游离的内含物更疏水 内含物。 原毒素对敏感幼虫的有效性 可以取决于内含物的疏水性。 以色列亚种产生由原毒素组成的内含物 对蚊子幼虫有效。 Israelensis的内含物为 从孢子中单独释放出来，可能是亲水性的， 这些幼虫在自然界中不易获得。如果夹杂物 以色列人被包裹在外孢壁内， 原毒素应该更容易获得，因此更有效， 生物防治剂。 初步规划的目的 研究是为了确定外孢壁对 伴孢内含物的疏水性，并确定 工程的可行性，通过遗传技术，原毒素的 孢子外壁内的以色列孢子。 %%% 这是一项规划研究，以确定发展的可行性 一种有效杀灭蚊子幼虫的生物杀虫剂。 的 一种方法是利用天然的抗幼虫蛋白 由细菌在孢子形成过程中产生的。 苔藓- 人类和其他动物传播的疾病代表了一种极端的 严重的世界卫生和经济问题，特别是 第三世界;只有一个，疟疾，是第一个原因， 儿童死亡率最高。 化学杀虫剂不是 只是因为它们对动物的毒性和 环境，但它们变得越来越不有效， 昆虫对它们的抵抗力越来越强。 了这项研究 因此，生物虫害防治对这两个方面都具有重要意义。 人类健康和环境。

Bacillus thuringiensis is a Gram-positive sporulating bacterium that produces large amounts of sporulation specific proteins. These proteins accumulate as parasporal inclusions and are protoxins with selective activity for insect larvae. Generally, the inclusion is deposited outside the exosporium and is released into the environment separately from the spore. In subspecies finitimus, however, the inclusion and the spore share the common exosporium and are released together. The exosporium is more hydrophobic than the spore (Koshikawa et al., 1989), and exosporium enclosed inclusions are expected to be more hydrophobic than free inclusions. The availability of protoxins to susceptible larvae may be dependent upon the hydrophobicity of the inclusions. Subspecies israelensis produces inclusions composed of protoxins active on mosquito larvae. The inclusions of israelensis are released separately from the spore and are probably hydrophilic and not readily available to these larvae in nature. If the inclusions of israelensis were enclosed within the exosporium, then the protoxin should be more accessible and thus a more effective biological control agent. The aims of the preliminary planning study are to determine the effects of the exosporium on the hydrophobicity of parasporal inclusions, and to determine the feasibility of engineering, by genetic techniques, the protoxin of israelensis inside an exosporium. %%% This is a planning study to determine the feasibility of developing a biological insecticide effective against mosquito larvae. The approach is to take advantage of natural antilarval proteins produced by a bacterium in the course of sporulation. Mosquito- borne diseases of man and other animals represent an extremely significant world health and economic problem, particularly in the third world; one alone, malaria, is the number one cause of childhood mortality in the world. Chemical insecticides are not only unattractive because of their toxicity to animals and the environment, but they are becoming less and less effective as insects increasingly develop resistance to them. This research on biological pest control is therefore of great significance to both human health and the environment.