β-内酰胺酶过度表达对大肠杆菌的周质酶释放和其他生理效应。

Release of periplasmic enzymes and other physiological effects of beta-lactamase overproduction in Escherichia coli.

机构信息

Department of Chemical Engineering, Cornell University, Ithaca, New York 14853, USA.

出版信息

Biotechnol Bioeng. 1988 Sep 5;32(6):741-8. doi: 10.1002/bit.260320603.

DOI:10.1002/bit.260320603

Abstract

When Escherichia coli containing the plasmid ptac11 is induced with 10(-4) M isopropyl-beta-thiogalactopyranoside (IPTG), 90% of the beta-lactamase activity of an overnight culture is present in the medium. The high extracellular activity of beta-lactamase does not result from cell lysis but from an increase in the permeability of the outer membrane. The excreting cells release several other periplasmic enzymes into the extracellular fluid and are more sensitive to lysis by detergents. It was also shown that in these cells the level of two membrane proteins, OmpA and OmpC, is decreased. None of these phenomena were observed with the plasmid pDW17, which has a mutation in the tac promoter that reduces its activity to one fourth of the tac promoter.

摘要

当含有质粒 ptac11 的大肠杆菌被 10(-4) M 的异丙基-β-D-硫代半乳糖苷（IPTG）诱导时，过夜培养物中 90%的β-内酰胺酶活性存在于培养基中。β-内酰胺酶的高细胞外活性不是由于细胞裂解引起的，而是由于外膜通透性的增加。分泌细胞将几种其他周质酶释放到细胞外液中，并且对去污剂的裂解更敏感。还表明，在这些细胞中，两种膜蛋白 OmpA 和 OmpC 的水平降低。在用质粒 pDW17 进行实验时，没有观察到这些现象，该质粒在 tac 启动子中有一个突变，使其活性降低到 tac 启动子的四分之一。