Naundorf G, Aumen N G
Freshwater Biology Program, Department of Biology, University of Mississippi, University 38677.
Can J Microbiol. 1990 Aug;36(8):525-9. doi: 10.1139/m90-092.
Ammonia-induced cell envelope injury was examined in pure cultures of Escherichia coli and Enterobacter aerogenes. Cell injury, as determined by the ratio of colony-forming units on m-T7 agar to colony-forming units on m-Endo agar, increased with exposure to increasing concentrations of ammonia. Cell envelopes appeared to be the site of injury as indicated by increasing susceptibility to lysozyme with increasing ammonia concentration. Cells exposed to ammonia also exhibited more cellular leakage than control cells. Leakage from cells exposed to ammonia included proteins, and all leaked substances increased in concentration as ammonia concentrations increased. The concentration of 2-keto-3-deoxyoctonate (KDO) in the outer membrane of E. coli increased with ammonia exposure, while KDO concentration in the outer membrane of E. aerogenes decreased. The results suggest that exposure of E. coli cells to high concentrations of ammonia disrupts the outer membrane and lipopolysaccharide-associated proteins, while E. aerogenes cells are affected through the disruption of bonds between KDO and the outer membrane.
在大肠杆菌和产气肠杆菌的纯培养物中检测了氨诱导的细胞包膜损伤。通过m-T7琼脂上的菌落形成单位与m-远藤琼脂上的菌落形成单位之比确定的细胞损伤，随着暴露于浓度不断增加的氨而增加。随着氨浓度的增加，对溶菌酶的敏感性增加，表明细胞包膜似乎是损伤部位。暴露于氨的细胞也比对照细胞表现出更多的细胞渗漏。暴露于氨的细胞的渗漏物包括蛋白质，并且随着氨浓度的增加，所有渗漏物质的浓度都增加。随着氨暴露，大肠杆菌外膜中2-酮-3-脱氧辛酸（KDO）的浓度增加，而产气肠杆菌外膜中KDO的浓度降低。结果表明，将大肠杆菌细胞暴露于高浓度的氨会破坏外膜和脂多糖相关蛋白，而产气肠杆菌细胞则通过KDO与外膜之间的键的破坏而受到影响。
