Forespore Engulfment During B. subtilis Sporulation

枯草芽孢杆菌孢子形成过程中前孢子的吞噬

• 批准号: 6837721
• 负责人: Kit J Pogliano
• 金额: $ 30.31万
• 依托单位: UNIVERSITY OF CALIFORNIA, SAN DIEGO
• 依托单位国家: 美国
• 财政年份: 1998
• 资助国家: 美国
• 起止时间: 1998-01-01 至 2006-12-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6837721
• 关键词: Forespore; Engulfment; During; B.; subtilis

EXCEED THE SPACE PROVIDED. Bacteria from the genera Bacillus and Clostridium produce unusually durable and long lived spores that are the infectious agent of Anthrax and Botulism, and which are assembled in the cytoplasm of another cell. This unique cell within a cell structure is produced by the phagocytosis-like process of engulfment, during which the membrane of the larger mother cell migrates around the smaller forespore, until it is completely enclosed within the mother cell cytoplasm. Engulfment provides a dramatic example of the dynamic capabilities of the bacterial cell, but its mechanism remains unclear. Previously, the only engulfment mutants blocked septal thinning, during which peptidoglycan within the septum is thinned in preparation for membrane migration. We have developed new tools for the study of engulfment, and identified mutants defective in membrane migration, and in the final step of engulfment, membrane fusion. The membrane fusion defective mutants affect a protein that is both highly conserved and essential in many species. This protein localizes to site of division and is involved in the final stages of chromosome segregation, suggesting that it may also be involved in membrane fusion at the completion of cell division, a process about which little is known. Sporulation-specific enzymes are required to hydrolyze peptidoglycan during septal thinning, and we will test if vegetative autolysins can partially substitute for the sporulation specific enzymes. Autolysins are found in all bacteria (the Bacillus subtilis genome is predicted encode more than 30 such enzymes), and are thought to allow peptidoglycan remodeling for cell elongation and division. However, these enzymes are potentially lethal, since unless they are tightly regulated both spatially and temporally, their activity can result in cell lysis. Indeed, the lethality of many commercial antibiotics requires autolysins. Engulfment provides an ideal system for understanding how bacteria control these potentially lethal enzymes, which are attractive targets for novel antibiotics. We will take a combined cell biological, genetic and biochemical approach to study the spatial regulation of peptidoglycan hydrolysis, the mechanism of membrane fusion in bacterial cells, as well as to understand how bacteria move and localize macromolecules within their cells. PERFORMANCE SITE ========================================Section End===========================================

超过提供的空间。 来自芽孢杆菌和梭状芽胞杆菌的细菌会产生异常耐用的孢子，这些孢子是炭疽和肉毒杆菌的感染剂，并在另一个细胞的细胞质中组装。这种独特的细胞结构中的这种独特的细胞是由吞噬的吞噬作用过程产生的，在此期间，较大的母细胞的膜在较小的前孔周围迁移，直到将其完全封闭在母细胞细胞质中为止。吞噬提供了细菌细胞动态能力的戏剧性例子，但其机制尚不清楚。以前，唯一的吞噬突变体阻止了间隔稀疏，在此期间，隔膜内的肽聚糖会稀释，以准备膜迁移。我们开发了用于研究吞噬的新工具，并确定了膜迁移中有缺陷的突变体，以及在吞噬的最后一步，膜融合。膜融合缺陷突变体会影响许多物种中高度保守且必不可少的蛋白质。该蛋白质定位于分裂部位，并参与了染色体隔离的最后阶段，这表明它在细胞分裂完成时也可能参与膜融合，这一过程鲜为人知。孢子孢子特异性酶在隔隔层中水解肽聚糖需要，我们将测试营养性自动蛋白是否可以部分代替孢子孢子的特定酶。在所有细菌中都发现了自脂蛋白（枯草芽孢杆菌基因组被预测编码30种此类酶），并被认为允许肽聚糖重塑细胞伸长和分裂。但是，这些酶可能是致命的，因为除非它们在空间和时间上受到严格的调节，否则它们的活性会导致细胞裂解。实际上，许多商业抗生素的致死性需要自动蛋白酶。吞噬提供了一个理想的系统，可以理解细菌如何控制这些潜在的致命酶，这些酶是新型抗生素的有吸引力的靶标。我们将采用一种组合细胞的生物学，遗传和生化方法来研究肽聚糖水解的空间调节，细菌细胞中膜融合的机制，以及了解细菌如何在其细胞中移动和定位大分子。表演站点=============================================================================================