PARASPORAL BODY FORMING BACILLI

附胞体形成杆菌

• 批准号: 3284443
• 负责人: Arthur I. Aronson
• 金额: $ 14.06万
• 依托单位: PURDUE UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 1985
• 资助国家: 美国
• 起止时间: 1985-09-05 至 1991-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/3284443
• 关键词: Bacillus; Bacillus cereus; bacterial genetics; bacterial toxins; bioassay; cytotoxicity; molecular cloning; plasmids

Bacillus thuringiensis is characterized by the production of a large, intracellular inclusion during sporulation. Each of these inclusions is comprised of one or a few classes of large polypeptides (protoxins) that are toxic for specific species of insect larvae. There is a spectrum of these toxins produced by subspecies of B. thuringiensis each with a unique pattern of toxicity for certain insect larvae. Included among these are many that cause major damage to crops and trees (Lepidoptera) as well as others that serve as carriers of human diseases, i.e. mosquitoes and flies. In some subspecies, more than one inclusion is formed and each contains a unique toxin. These polypeptides are produced during a portion of the sporulation process and comprise a substantial part of the protein synthetic activity during the period of formation. Several of these protoxin genes have been cloned from B. thuringiensis plasmids into B. subtilis E. coli shuttle vector and express sufficiently well in both organisms to permit determination of lethal doses for select neonate larvae. The basis for toxin specificity will be determined by comparing relative LC50's for parental B. thuringiensis strains, cloned protoxin genes (alone or in combination) and of B. cereus transcipients containing selected arrays of B. thuringiensis plasmids. B. thuringiensis subspecies and cloned genes will be chosen to provide a comparison of those with overlapping as well as non-overlapping specificities. Various regions of the cloned protoxin genes will be subcloned to examine toxicity levels as well as alterations in specificity. The regulation of protoxin synthesis in at least one subspecies is dependent on the activities of two cryptic plasmids. One plasmid affects the temperature of protoxin synthesis, the other the amount produced. Bioassay systems will be developed employing cloned protoxin genes plus cloned fragments of these regulatory plasmids in order to define the portion of each plasmid involved in regulation, whether there is a gene product and whether the regulatory function is at the level of transcription or elsewhere.

苏云金芽孢杆菌的特点是产生大量、 孢子形成过程中的细胞内包涵体。 这些内含物中的每一个都是 由一类或几类大多肽（原毒素）组成 对特定种类的昆虫幼虫有毒。 有一个频谱 这些由苏云金芽孢杆菌亚种产生的毒素各自具有独特的特性 对某些昆虫幼虫的毒性模式。 其中包括 许多对农作物和树木（鳞翅目）造成重大损害 其他作为人类疾病携带者的，即蚊子和 苍蝇。 在某些亚种中，形成多个内含物，并且每个内含物 含有一种独特的毒素。 这些多肽是在一部分过程中产生的 孢子形成过程的一部分，并包含蛋白质的很大一部分 形成期间的合成活动。 其中几个原毒素基因已从苏云金芽孢杆菌中克隆出来 将质粒导入枯草芽孢杆菌大肠杆菌穿梭载体并充分表达 在这两种生物体中都可以很好地确定选定的致死剂量 新生幼虫。 毒素特异性的基础将由以下因素确定 比较亲本苏云金芽孢杆菌克隆菌株的相对 LC50 原毒素基因（单独或组合）和蜡状芽孢杆菌转运体 含有选定的苏云金芽孢杆菌质粒阵列。 苏云金芽孢杆菌 将选择亚种和克隆基因来提供这些亚种和克隆基因的比较 具有重叠和非重叠的特性。 各个地区 克隆的原毒素基因将被亚克隆以检查毒性水平 以及特异性的改变。 至少一个亚种中原毒素合成的调节是 依赖于两个隐秘质粒的活性。 一个质粒影响 原毒素合成的温度，其他产生的量。 将利用克隆的原毒素基因以及 这些调节质粒的克隆片段，以定义 每个质粒参与调节的部分，是否有基因 产品以及监管功能是否处于 转录或其他地方。