EXTRACELLULAR CONTROL OF SPORE FORMATION IN BACILLUS-SUBTILIS
EXTRACELLULAR CONTROL OF SPORE FORMATION IN BACILLUS-SUBTILIS
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DOI：
10.1073/pnas.85.12.4369
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发表时间：
1988-06-01
影响因子：
11.1
通讯作者：
LOSICK, R
中科院分区：
文献类型：
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作者：
GROSSMAN, AD;LOSICK, R
革兰氏阳性杆菌枯草芽孢杆菌的孢子形成被经典地视为单细胞分化的一个例子，发生在对营养饥饿的反应中。我们提出的证据表明，枯草芽孢杆菌产生细胞外因子(s)是必需的，除了饥饿条件下，有效的产孢。该因子以细胞密度依赖的方式分泌和积累，因此在高密度细胞有效产孢的条件下，低密度细胞产孢差。从高密度生长的细胞中提取的条件培养基（无菌滤液）含有这种细胞外分化因子（EDF-A），并在正常饥饿条件下刺激低密度细胞的孢子形成。EDF-A具有耐热性、蛋白酶敏感性和可透析性，这表明它至少部分是寡肽。在spo0A和spo0B突变体中，EDF-A的产生减少或消除，这两个突变体在与负生长结束相关的许多过程中存在缺陷。abb的突变抑制了许多spo0A突变体的多效表型，恢复了EDF-A的产生。
Spore formation in the Gram-positive bacterium Bacillus subtilis has been classically viewed as an example of unicellular differentiation that occurs in response to nutritional starvation. We present evidence that B. subtilis produces an extracellular factor(s) that is required, in addition to starvation conditions, for efficient sporulation. This factor is secreted and accumulates in a cell density-dependent fashion such that cells at a low density sporulate poorly under conditions in which cells at a high density sporulate efficiently. Conditioned medium (sterile filtrate) from cells grown to a high density contains this extracellular differentiation factor (EDF-A) and stimulates spore formation of cells at low density under normal starvation conditions. EDF-A is heat-resistant, protease-sensitive, and dialyzable, indicating that it is at least in part an oligopeptide. Production of EDF-A is reduced or eliminated in spo0A and spo0B mutants, which are defective in many processes associated with the end of vegatative growth. Mutations in abrB, which suppress many of the pleiotropic phenotypes of spo0A mutants, restore production of EDF-A.