Lamb D H, Bott K F
J Bacteriol. 1979 Jan;137(1):213-20. doi: 10.1128/jb.137.1.213-220.1979.
A 1-mg/ml amount of threonine (8.4 mM) inhibited growth and sporulation of Bacillus subtilis 168. Inhibition of sporulation was efficiently reversed by valine and less efficiently by pyruvate, arginine, glutamine, and isoleucine. Inhibition of vegetative growth was reversed by asparate and glutamate as well as by valine, arginine, or glutamine. Cells in minimal growth medium were inhibited only transiently by very high concentrations of threonine, whereas inhibition of sporulation was permanent. Addition of threonine prevented the normal increase in alkaline phosphatase and reduced the production of extracellular protease by about 50%, suggesting that threonine blocked the sporulation process relatively early. 2-Ketobutyrate was able to mimic the effect of threonine on sporulation. Sporulation in a strain selected for resistance to azaleucine was partially resistant. Seventy-five percent of the mutants selected for the ability to grow vegetatively in the presence of high threonine concentrations were found to be simultaneously isoleucine auxotrophs. In at least one of these mutants, the threonine resistance phenotpye could not be dissociated from the isoleucine requirement by transformation. This mutation was closely linked to a known ilvA mutation (recombination index, 0.16). This strain also had reduced intracellular threonine deaminase activity. These results suggest that threonine inhibits B. subtilis by causing valine starvation.
1毫克/毫升的苏氨酸（8.4毫摩尔）可抑制枯草芽孢杆菌168的生长和孢子形成。缬氨酸可有效逆转孢子形成的抑制作用，而丙酮酸、精氨酸、谷氨酰胺和异亮氨酸的逆转作用则较弱。天冬氨酸、谷氨酸以及缬氨酸、精氨酸或谷氨酰胺可逆转对营养生长的抑制作用。在基本生长培养基中的细胞仅会被极高浓度的苏氨酸短暂抑制，而对孢子形成的抑制是永久性的。添加苏氨酸可阻止碱性磷酸酶的正常增加，并使细胞外蛋白酶的产生减少约50%，这表明苏氨酸在相对早期就阻断了孢子形成过程。2-酮丁酸能够模拟苏氨酸对孢子形成的影响。对氮杂亮氨酸具有抗性的菌株中的孢子形成具有部分抗性。在高浓度苏氨酸存在下选择能够营养生长的突变体中，75%被发现同时是异亮氨酸营养缺陷型。在这些突变体中至少有一个，苏氨酸抗性表型不能通过转化与异亮氨酸需求分离。该突变与已知的ilvA突变紧密连锁（重组指数为0.16）。该菌株的细胞内苏氨酸脱氨酶活性也有所降低。这些结果表明，苏氨酸通过导致缬氨酸饥饿来抑制枯草芽孢杆菌。
