Suppression by the ColV,I-K94 plasmid of inhibitor sensitivities in ompA mutants of Escherichia coli

Abstract

A series of ompA mutants derived from Escherichia coli K12 strains showed increased sensitivity (compared with the ompA+ parents) to aminoglycoside antibiotics and to other cationic agents including polymyxin B. One tested mutant also showed increased sensitivity to nafcillin and fusidic acid, but not to the hydrophilic ampicillin. All these inhibitor sensitivities in the ompA mutants were suppressed by ColV, I-K94 and by certain other ColV plasmids, but not by any of the other tested large plasmids. Suppression correlated with the production of the VmpA protein, but transfer and colicin components were not needed for suppression. Further comparison of the ompA and vmpA genes and their products was made and it indicated that there is little if any homology between the genes, that the synthesis of their products is regulated by quite different mechanisms, and that regions of these gene products exposed at the cell surface show different susceptibility to protease attack after denaturation.

Exposure of Escherichia colito acid habituation conditions sensitizes it to alkaline stress

“…(relA); CF1652 PALS10 (CFl652 relA+); TA15 (melBLid, rpsL, A 1ucZY); NM81 (TA15 nhuA, KanK); AB2847 (tsr, mulT, aroB); H2300 (AB2847 A tonB); 6482 leuB6,tonA23,luc Y I ,proC83,purE42,supE44,galK2,trpE38,UJbDI,urg77,rpsLI09,ilvA681,metA160,7157 (6482 katF3,sthAIS,glpR201,kafCI6); HN678 (gulK2,sup0,strR, (Reakes et al 1988) showed no trace of OmpC protein.…”

Ivnovlement of the OmpA protien in L-leucine-induced acid sensitivity

“…Calvo; strains JA199 (trpE5, leu-6, thi, hsdR, hsdM+) and NK1 UA199 cysB) from D r N. Kredich. Strains 1157-4 (1157phoE+,proA+), RJR203 (thr, leu, thi, lacy, ara, ,rjd, rpsL, lamB, ompA2101, colv, 1-K94), 1829, 1 829-TetR (1 829 Izimd, tetracycline-resistant), 1829-KanR' (1829 fur, kanamycin-resistant), 1829-KanR3 (1829 nhaA, kanamycin-resistant) and 1829-AmpR (1829 hns, ampicillin-resistant) were all produced in this laboratory and have been described previously (Reakes et al 1988 ;Rowbury and Hussain 1996;. Strains MC4100 PALS 10 and AT142 PALS10 were made by transformation with PALS10 DNA and strain TA15 pJP102 by transformation with pJP102 DNA (see below).…”

“…After setting, phage K3 suspensions were dropped onto the agar surfaces and plates incubated for 20-30 h at 37°C. Colonies growing in the cleared areas were purified and membranes tested from OmpA protein as described by Reakes et al (1988).…”