Mechanism on germination and formation of bacterial spores.

研究表明，蛋白酶和孢子皮层裂解酶参与了细菌孢子的萌发过程，我们在B的孢子中寻找这些酶。cereus和C.产气荚膜杆菌在萌发过程中，在萌发培养基中释放皮层溶解酶。来自B的酶。对蜡状芽孢杆菌进行了纯化和氨基端序列测定，结果表明其与目前报道的细胞壁裂解酶的氨基酸序列没有同源性。分离的酶破坏了敏感孢子的肽聚糖，伴随着相变暗，以类似于萌发的方式。此外，该酶不能分解来自营养细胞的细胞壁的肽聚糖。这些观察结果强烈表明，皮层裂解酶分离这里是发芽特异性肽聚糖降解酶。一种酶表现出非常相似的酶的特性，也检测到孢子的Cl。产气荚膜杆菌遗憾的是，在本实验中没有检测到参与发芽的蛋白酶。而从B中分离到2种与孢子相关的类枯草杆菌蛋白酶。蜡状芽孢杆菌的蛋白酶与枯草杆菌蛋白酶的性质不同，而在营养细胞培养中未检测到这些酶，表明这些蛋白酶是在芽孢形成过程中合成的。利用抗皮层裂解酶抗体对皮层裂解酶在孢子中的定位及其激活过程进行了研究。

It is of importance for food preservatives to inactivate heat-resistant bacterial spores which are hardly sterilized under commercial pasteurization, and the understanding of germination mechanism in molecular level should be helpful in the field of food industry.Several lines of evidence had indicated that protease and spore-cortex lytic enzyme are involved in the germination process of bacterial spores, and we looked for those enzymes in spores of B. cereus and Cl. perfringens. A cortex lytic enzyme was released in the germination medium during germination. The enzyme from B. cereus was purified and its amino-terminal sequence determined did not show any homology with those of cell wall lytic enzyme reported so far. The isolated enzyme disrupted peptidoglycan of sensitized-spores accompanying with a phase darkening, in a manner similar to germination. Furthermore, the enzyme was incapable of decomposing peptidoglycan of cell wall derived from vegetative cells. These observations strongly indicate that the cortex lytic enzyme isolated here is germination-specific peptidoglycan-degrading enzyme. An enzyme showing quite similar characteristics to the enzyme was also detected in spores of Cl. perfringens. Unfortunately, protease involved in germination was not detected in the present experiment. However, 2 types of spore-associated subtilisin-like enzyme were isolated from B. cereus, which differ in the properties from subtilisin, and those enzyme were not detected in the culture of vegetative cells, suggesting that the proteases were synthesized during sporulation. Studies on the location of cortex lytic enzyme in spores and on its activation process are in progress using anti-cortex lytic enzyme antibody.