CYCLIC 3',5'-ADENOSINE-MONOPHOSPHATE PHOSPHODIESTERASE MUTANTS OF SALMONELLA-TYPHIMURIUM
CYCLIC 3',5'-ADENOSINE-MONOPHOSPHATE PHOSPHODIESTERASE MUTANTS OF SALMONELLA-TYPHIMURIUM
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DOI：
10.1128/jb.122.3.1081-1090.1975
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发表时间：
1975-01-01
影响因子：
3.2
通讯作者：
AMES, BN
中科院分区：
文献类型：
--
作者：
ALPER, MD;AMES, BN
已经设计了缺乏环3 '，5' 7-腺苷一磷酸（cAMP）磷酸二酯酶的鼠伤寒沙门氏菌突变体的阳性选择程序。编码这种酶的基因（cpd）已被定位在染色体上，并显示使用噬菌体P22与metC共转导25%。突变体已被用来研究的作用，在控制基因的表达是已知的依赖于cAMP的酶。在这些突变体中，已经观察到这些基因中的一些而不是其他基因的调节的显著改变。缺乏cAMP磷酸二酯酶的突变体比其亲本对似乎通过cAMP依赖性转运系统进入细胞的各种抗生素更敏感。它们在琥珀酸盐-氨-盐和葡萄糖-脯氨酸-盐培养基上比野生型生长更快，并且在葡萄糖、柠檬酸盐或甘油-氨盐培养基上被添加的cAMP抑制，而野生型不受影响。鼠伤寒沙门氏菌在甘油或柠檬酸盐培养基上的生长和菌株中酸性己糖磷酸酶的水平均不受cAMP磷酸二酯酶损失的影响。此外，突变株对高水平的cAMP极其敏感。在不能合成cAMP的菌株（腺苷酸环化酶阴性）中cAMP磷酸二酯酶的损失使表达代谢产物敏感表型对外源性cAMP的需求减少10倍。这些结果表明，通过控制细胞中的cAMP水平，磷酸二酯酶可能参与调节某些类别的分解产物敏感的操纵子，并保护细胞免受高水平的cAMP。
Positive selection procedures for mutants of Salmonella typhimurium lacking cyclic 3', 5'7-adenosine monophosphate (cAMP) phosphodiesterase have been devised. The gene (cpd) coding for this enzyme has been located on the chromosome and shown to be 25% co-transducible with metC using phage P22. The mutants have been used to investigate the role of the enzyme in the control of genes whose expression is known to be dependent on cAMP. Significant alterations in the regulation of some but not others of these genes have been observed in these mutants. Mutants lacking the cAMP phosphodiesterase are more sensitive than their parents to a variety of antibiotics that appear to enter the cell through cAMP-dependent transport systems. They grow faster than the wild type on succinate-ammonia-salts, and glucose-proline-salts media and are inhibited by added cAMP on glucose, citrate, or glycerol-ammonia salts media whereas the wild type is unaffected. Neither the growth of Salmonella typhimurium on glycerol or citrate media nor the level of acid hexose phosphatase in the strain is affected by the loss of cAMP phosphodiesterase. In addition, the mutant strains are extremely sensitive to high levels of cAMP. Loss of the cAMP phosphodiesterase in strains unable to synthesize cAMP (adenyl cyclase negative) reduces by 10-fold the requirement for exogenous cAMP for expression of catabolite-sensitive phenotypes. These results suggest that through its control of cAMP levels in the cell the phosphodiesterase may be involved in the regulation of certain classes of catabolite-sensitive operaons and also in protecting the cell against high levels of cAMP.