Study on Inhibition of Septum Formation of Bacteria

以蜡样芽孢杆菌JCM 2152为原料，经亚硝基胍处理获得蜡样芽孢杆菌温度敏感突变体ts-4。在45°C富集培养基中，蜡样芽孢杆菌ts-4获得了同步染色体复制。在染色体复制开始后的10、40和90分钟，将细胞样本转移到产孢培养基中。在30ºC培养20小时后，测定产孢率。蜡样芽孢杆菌ts-4的产孢能力在染色体复制开始后40 min达到最高，在复制开始后90 min下降。其余细胞复制开始后在30‰的温度下培养120 min，先用10 μ ml n -乙酰酶sg和2.5 μ ml溶菌酶处理，再用1%的Briji 58和0.4%的SDS处理。比较了10、40和90分钟转移细胞的染色体蛋白的双向电泳图谱。转染40 min后的细胞染色体中10种不同蛋白的含量显著减少，但另外3种蛋白的含量增加。在启动后，还比较了重新合成的染色体蛋白的二维电泳模式。从蜡样芽孢杆菌DNA纤维素柱制备的DNA结合蛋白。在每一种情况下，在40分钟转移的细胞中，相同的3种不同蛋白质的数量都大大增加。这些蛋白似乎控制蜡样芽孢杆菌ts-4的孢子形成。

Bacillus cereus temperature-sensitive mutant ts-4 was obtained from Bacillus cereus JCM 2152 by the treatment with nitrosoguanidine. Synchronous chromosome replication was obtained in a culture of B. cereus ts-4 growing in a rich medium at 45ﾟC. At 10, 40, and 90 min from the start of chromosomal replication, samples of cells were transferred to a sporulation medium. After cultivation at 30 ﾟC for 20 hr, the sporulation rate was measured.The capacity of B. cereus ts-4 to sporulate was highest at 40 min after chromosome replication began, and had declined at 90 min. Other cells were cultured at 30ﾟC for 120 min after the start of replication, and their chromosomes were prepared by treatment first with 10 uglml N-acetylmuramidase SG-and 2.5 mug/ml lysozyme, and later with 1% Briji 58 and 0.4% SDS. Patterns of two-dimensional electrophoresis of the chromosomal proteins from cells transferred at 10, 40, and 90 min were compared. The chromosomes of cells transferred at 40 min had greatly decreased amounts of 10 different proteins, but the amounts of three other proteins had increased. Patterns of two-dimensional electrophoresis were also compared in de novo synthesized cromosomal proteins after the start. of chromosome replication and in DNA binding proteins prepared from B. cereus DNA cellulose column. Amounts of the same 3 different proteins greatly increased in the cells transferred at 40 min in every case. These proteins seem to control the initiation of sporulation by B. cereus ts-4.