Stinnett J D, Eagon R G
Can J Microbiol. 1975 Nov;21(11):1834-41. doi: 10.1139/m75-266.
Ethylenediaminetetraacetate (EDTA) has been previously shown to cause the release of a complex of protein and lipoplysaccharide (PrLPS) from the outer membrane of Pseudomonas aeruginosa. In this present work, cells of P. aeruginosa were incubated in a solution of EDTA, phosphate buffer, and hypertonic sucrose to prepare osmoplasts (osmotically sensitive cells). Osmoplasts were able to undergo self-repair of the outer-membrane damage resulting from EDTA treatment and to regain osmotic stability when incubated in growth medium/hypertonic sucrose for 2 h in the absence of exogenous PrLPS and in the absence of cell division. This repair process was inhibited by either chloramphenicol or KCN. Examination of freeze-etched preparations demonstrated that 40% of the PrLPS units in the outer membrane were removed by EDTA; after 2 h in growth medium/hypertonic sucrose, cells were able to repair this damage by synthesizing and inserting new PrLPS units into the outer membrane. Osmoplasts could also be restored to osmotic stability by suspension in osmoplast supernatant fluid containing PrLPS and Mg2+. This latter restoration process, which was not inhibited by chloramphenicol or KCN, was purely physical while the self-repair restoration process was metabolic. These data are consistent with the concept that the outer membrane proteins, especially the PrLPS units play a role in stabilizing the cell envelope and in maintaining the osmotic stability of P. aeruginosa.
乙二胺四乙酸（EDTA）先前已被证明可导致铜绿假单胞菌外膜释放蛋白质与脂多糖复合物（PrLPS）。在本研究中，将铜绿假单胞菌细胞置于EDTA、磷酸盐缓冲液和高渗蔗糖溶液中孵育以制备原生质球（对渗透压敏感的细胞）。原生质球能够对外膜因EDTA处理而造成的损伤进行自我修复，并在无外源PrLPS且无细胞分裂的情况下于生长培养基/高渗蔗糖中孵育2小时后恢复渗透稳定性。氯霉素或KCN均可抑制此修复过程。对冷冻蚀刻制剂的检查表明，外膜中40%的PrLPS单元被EDTA去除；在生长培养基/高渗蔗糖中孵育2小时后，细胞能够通过合成新的PrLPS单元并将其插入外膜来修复这种损伤。将原生质球悬浮于含有PrLPS和Mg2+的原生质球上清液中也可使其恢复渗透稳定性。后一种恢复过程不受氯霉素或KCN的抑制，是纯粹的物理过程，而自我修复恢复过程是代谢过程。这些数据与外膜蛋白尤其是PrLPS单元在稳定细胞膜及维持铜绿假单胞菌渗透稳定性中起作用这一概念相符。
