环化腺苷酸对细菌生长的影响

THE EFFECT OF 3’,5’-CYCLIC ADENYLIC ACID (cAMP) ON THE GROWTH OF BACTERIA

用大肠杆菌(Escherichia coli As 1.797)、北京棒状杆菌(Corynebacterium pekinense AS 1.299)和巨大芽孢杆菌(Bacillus megaterium AS 1.217)研究了细胞内环化腺苷酸(cAMP)浓度和外源cAMP对细胞生长的影响。结果表明,大肠杆菌在不同碳源中生长时,细胞的生长量随细胞内cAMP浓度升高而降低。在以葡萄糖作碳源时,细胞内cAMP浓度低,外源cAMP对生长有抑制作用,而cAMP的类似物5′-AMP则无抑制作用。在以乳糖、麦芽糖和甘油分别作碳源时,细胞内cAMP浓度高,外源cAMP对生长无影响。北京棒状杆菌以葡萄糖作碳源时,细胞生长也受外源cAMP的抑制,但cAMP的抑制作用不是专一的,它的作用可用类似物5′-AMP来代替。自身不含cAMP的巨大芽孢杆菌在不同碳源(包括葡萄糖)中生长时,生长不受外源cAMP抑制,也不受5′-AMP的影响。因此认为,cAMP不是细菌生长的必需物,而是生长调节物,但这种调节物对巨大芽孢杆菌无效。

The effect of intracellular cAMP level on the growth of bacteria was studied with E. coli AS 1.797, Corynebacterium pekinense AS 1.299 and Bacillus megaterium AS 1.217. The experimental results show that the growth of E. coli AS 1.797 was decreased with increasing cAMP level in cell. With glucose as the sole carbon source, intracellular cAMP is low, and growth of E. coli AS 1.797 was inhibited by exogenous cAMP, but the analog metabolite of cAMP-5'-AMP had no effect on growth. When E. coli AS 1.797 was grown in media containing lactose, maltose and glycerin respectively, intracetlular cAMP level is high, and exogenous cAMP did not inhibited the cell growth. When Corynebacterium pekinense AS 1.299 took glucose as carbon source the growth of this bacterium was also inhibited by exogenous cAMP, bur the inhibition of cAMP was not specific, its role can be exchanged by 5'-AMP. B. megaterium AS 1.217 cultivated in different carbon source (include glucose) do not contain cAMP in cell, and its growth was not inhibited by exogenous cAMP. 5'-AMP had also no effect on the growth of this bacterium. Thus, the conclusion seems that the cAMP is not essential for the growth of bacteria, and it is a regulator that act a negative regulation in cell growth, but this regulator is of no effect for the growth of B. megaterium AS 1.217.