干扰分化的代谢物缺乏或过量。
Deficiencies or excesses of metabolites interfering with differentiation.
作者信息
Freese E, Ichikawa T, O Y K, Freese E B, Prasad C
出版信息
Proc Natl Acad Sci U S A. 1974 Oct;71(10):4188-93. doi: 10.1073/pnas.71.10.4188.
Auxotrophic mutants of Bacillus subtilis need much higher concentrations of the required adenine, nicotinic acid, riboflavin, thiamine, or tryptophan for optimal sporulation than for maximal growth. Acetate can partially replace thiamine, indicating the importance of the pyruvate dehydrogenase system for differentiation. A glycerol-requiring mutant can sporulate only if its cells contain a small concentration of L-alpha-glycerol phosphate during development. This can best be achieved by excess (>/=5 mM) of extracellular alpha-glycerol phosphate, which enters B. subtilis very slowly. The results show that both biosynthetic and catabolic enzymes are often needed to maintain the precise balance of metabolites required for differentiation. Mutants unable to catabolize fructose 6-phosphate, glucose 6-phosphate, or alpha-glycerol phosphate do not sporulate as long as these compounds accumulate inside the cells; their development is blocked before prespore septa have formed.
枯草芽孢杆菌的营养缺陷型突变体在进行最佳芽孢形成时，所需的腺嘌呤、烟酸、核黄素、硫胺素或色氨酸的浓度要比最大生长时高得多。乙酸盐可以部分替代硫胺素，这表明丙酮酸脱氢酶系统对分化很重要。一个需要甘油的突变体只有在其细胞在发育过程中含有低浓度的L-α-甘油磷酸时才能形成芽孢。这最好通过过量（≥5 mM）的细胞外α-甘油磷酸来实现，α-甘油磷酸进入枯草芽孢杆菌的速度非常慢。结果表明，生物合成酶和分解代谢酶通常都需要维持分化所需代谢物的精确平衡。只要这些化合物在细胞内积累，无法分解代谢6-磷酸果糖、6-磷酸葡萄糖或α-甘油磷酸的突变体就不会形成芽孢；它们的发育在芽孢前隔膜形成之前就被阻断了。
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