[Beta-lactamase synthesis and excretion in a non-leaky wild strain and a leaky mutant of Escherichia coli K-12].
After transformation of Escherichia coli strains with plasmid pBR 322 and growth in rich L medium, the total amount of beta-lactamase produced, strongly decreased when the temperature was raised from 30 to 42 degrees C, but increased after addition of ampicillin or tetracycline to the medium. beta-lactamase was synthesized and exported into the periplasmic space of wild-type strain, but was not significantly released into the extracellular medium, after growth at low temperature. We have identified an E. coli mutant which excreted up to 90% of total amount of beta-lactamase activity, any temperature. This mutant has been used as an indicator strain, for the development of an in situ test allowing the detection of beta-lactamase excretion.
D000667:Ampicillin / Q000494:pharmacology; D004790:Enzyme Induction / Q000187:drug effects; D004926:Escherichia coli / Q000187:drug effects / Q000201:enzymology* / Q000235:genetics; D009154:Mutation; D010641:Phenotype; D010957:Plasmids / Q000187:drug effects; D013696:Temperature; D013752:Tetracycline / Q000494:pharmacology; D001618:beta-Lactamases / Q000096:biosynthesis* / Q000235:genetics
D000667:Ampicillin; D001618:beta-Lactamases; D013752:Tetracycline
Synthèse et excrétion de beta-lactamase chez une souche sauvage non excrétrice et un mutant excréteur d'Escherichia coli K-12.