Foster S J, Johnstone K
Biochem J. 1986 Aug 1;237(3):865-70. doi: 10.1042/bj2370865.
The germination response of spores of Bacillus megaterium KM, as measured by loss of A600, is more than 95% inhibited by 1 mM-HgCl2. Two Hg2+-sensitive sites (referred to as 'sites I and II') have been identified during germination. Site I represents a pre-commitment event and can be protected from HgCl2 by 50 mM-D-alanine, whereas site II represents a post-commitment event and is not D-alanine-protectable. At 1 mM-HgCl2, 25% of the spore population becomes committed to germinate, but an A600 loss of less than 5% occurs. In this system, loss of heat resistance was associated with commitment, whereas selective cortex hydrolysis, release of pyridine-2,6-dicarboxylic acid, Zn2+ and soluble peptidoglycan, as well as loss of refractility, were identified as post-commitment events. The commitment event was reversibly inhibited by several proteinase inhibitors and a membrane bulking agent. A model of spore germination based on these results is presented.
巨大芽孢杆菌KM菌株孢子的萌发反应，以A600的降低来衡量，1 mM的HgCl2可抑制其超过95%。在萌发过程中已鉴定出两个对Hg2+敏感的位点（称为“位点I和位点II”）。位点I代表一个预决定事件，可被50 mM的D-丙氨酸保护免受HgCl2影响，而位点II代表一个决定后事件，不能被D-丙氨酸保护。在1 mM的HgCl2作用下，25%的孢子群体开始进入萌发状态，但A600的降低小于5%。在这个系统中，耐热性的丧失与决定过程相关，而选择性皮层水解、吡啶-2,6-二羧酸、Zn2+和可溶性肽聚糖的释放以及折光性的丧失，则被确定为决定后事件。决定事件可被几种蛋白酶抑制剂和一种膜膨胀剂可逆地抑制。基于这些结果提出了一个孢子萌发模型。
