Doering J L, Bott K F
J Bacteriol. 1972 Oct;112(1):345-55. doi: 10.1128/jb.112.1.345-355.1972.
The amino acid requirements for sporulation were studied by use of auxotrophic mutants of Bacillus subtilis 168. Cells were grown to T(0) in medium containing the test amino acid and were then transferred to a minimal medium lacking that amino acid. Omission of leucine caused no reduction in sporulation. Omission of methionine, lysine, and phenylalanine appeared to cause reduced levels of sporulation, and sporulation was completely inhibited when isoleucine, tryptophan, and threonine were omitted. The amino acids in this third class showed a sequence of requirements, with tryptophan required earlier than isoleucine, which in turn was required earlier in the sporulation process than threonine. Isoleucine omission did not affect the early sporulation functions of extracellular protease formation or septum formation, but prevented the increased levels of protein synthesis and oxygen consumption that normally accompany early sporulation stages. Isoleucine did not appear to be metabolized to other compounds in significant amounts during sporulation. The role of isoleucine in the sporulation process remains unclear.
利用枯草芽孢杆菌168的营养缺陷型突变体研究了芽孢形成的氨基酸需求。细胞在含有测试氨基酸的培养基中生长至T(0)，然后转移至缺乏该氨基酸的基本培养基中。省略亮氨酸不会导致芽孢形成减少。省略蛋氨酸、赖氨酸和苯丙氨酸似乎会导致芽孢形成水平降低，而省略异亮氨酸、色氨酸和苏氨酸时，芽孢形成会完全受到抑制。这第三类氨基酸显示出需求顺序，色氨酸比异亮氨酸更早被需要，而异亮氨酸在芽孢形成过程中又比苏氨酸更早被需要。省略异亮氨酸不影响细胞外蛋白酶形成或隔膜形成等早期芽孢形成功能，但阻止了通常伴随早期芽孢形成阶段的蛋白质合成和氧气消耗水平的增加。在芽孢形成过程中，异亮氨酸似乎不会大量代谢为其他化合物。异亮氨酸在芽孢形成过程中的作用仍不清楚。
