Endospore Formation in Bacillus
Endospore Formation in Bacillus
复制标题
芽孢杆菌内生孢子的形成
DOI：
--
复制
发表时间：
1984
期刊：
影响因子：
--
通讯作者：
P. Youngman
中科院分区：
文献类型：
--
作者：
R. Losick;P. Youngman
引言几种革兰氏阳性菌指出，他们精心的适应性反应的条件下，营养耗尽。这些发育变化有时是短暂和可逆的，如在某些链球菌、葡萄球菌和芽孢杆菌属物种中获得DNA摄取和转化的“能力”，但也包括真正的细胞分化的例子，如在大多数芽孢杆菌和链霉菌属物种中孢子形成的情况。在芽孢杆菌和链霉菌中，孢子形成实际上是一系列复杂的生理和形态变化的顶点，并非所有这些变化都与孢子的产生直接相关。例如，许多芽孢杆菌属物种在形成孢子时产生并分泌大量的外切酶和小分子，如蛋白酶和抗生素（这些物质中的大多数在孢子形成中没有明显的作用），而链霉菌属物种因其在达到稳定期（无论是否形成孢子）时产生的抗生素和其他次级代谢物的多样性而众所周知。苏云金芽孢杆菌特有的一个非常显著的孢子形成相关事件（与活孢子的形成无关）是细胞内晶体蛋白聚集体（“晶体毒素”）的产生，其具有极强的杀虫特性（Bechtel和Bulla 1976）。毫不奇怪，伴随并包含这些生物体中孢子形成过程的复杂变化依赖于多个染色体位置处的多组基因的时间调节表达。本文总结了几个实验室的工作，从事确定如何在分子水平上，这样的调节完成…
INTRODUCTION Several species of gram-positive bacteria are noted for their elaborate adaptive responses to conditions of nutrient depletion. These developmental changes are sometimes transient and reversible, as in the attainment of “competence” for DNA uptake and transformation among some Streptococcus , Staphylococcus , and Bacillus species, but also include examples of true cellular differentiation, as in the case of spore formation in most Bacillus and Streptomyces species. In both Bacillus and Streptomyces , sporulation is actually the culmination of a complex sequence of physiological and morphological changes, not all of which are directly connected with the generation of a spore. Many Bacillus species, for example, produce and secrete an abundance of exoenzymes and small molecules, such as proteases and antibiotics, as they sporulate (most of these substances having no apparent role in spore formation), and Streptomyces species are well known for the diversity of antibiotics and other secondary metabolites they produce as they reach stationary phase (whether or not spores are formed). A very striking sporulation-associated event (irrelevant to the formation of a viable spore) peculiar to Bacillus thuringiensis is the production of an intracellular crystalline protein aggregate (the “crystal toxin”), which has extremely potent insecticidal properties (Bechtel and Bulla 1976). Not surprisingly, the complex changes that accompany and comprise the process of Sporulation in these organisms are dependent on the temporally regulated expression of many sets of genes at multiple chromosomal locations. This paper summarizes the work of several laboratories engaged in determining how, at the molecular level, such regulation is accomplished...