Effects of lincomycin on synthesis of TEM beta-lactamase by Escherichia coli.
Sub-inhibitory concentrations of lincomycin slightly inhibit growth of Escherichia coli carrying plasmid RP4 and cause a 2-fold increase in TEM-2 beta-lactamase. To analyze this effect, cultures were pulse-labeled with [3H]leucine, chased with non-radioactive leucine and immunoprecipitated with anti-beta-lactamase antiserum. The synthesis rate of beta-lactamase was two times higher in inhibited cultures than in control cultures. No significant decrease of labeled enzyme occurred during the 30 minutes chase, indicating no degradation of beta-lactamase. The rate of maturation of pre-beta-lactamase was determined by measuring the decrease in the amount of pre-beta-lactamase after a 1-minute labeling interval. There was no significant difference between the control and lincomycin-treated cultures, indicating that posttranslational translocation is not involved in the stimulation. Both plasmid encoded and chromosomally encoded TEM-1 beta-lactamase increased in the presence of lincomycin. The effects of other protein synthesis inhibitors on the synthesis of TEM-1 beta-lactamase were examined. The stimulation of beta-lactamase synthesis by lincomycin appears to be specific for macrolide and related antibiotics and is not a general phenomenon resulting from partial inhibition of protein synthesis.
Okabe
A
A
Department of Microbiology, Kagawa Medical School, Japan.
Matsushita
O
O
Hayashi
H
H
D000900:Anti-Bacterial Agents / Q000494:pharmacology; D002876:Chromosomes, Bacterial / Q000187:drug effects; D004926:Escherichia coli / Q000187:drug effects / Q000201:enzymology / Q000235:genetics; D007158:Immunologic Techniques; D008034:Lincomycin / Q000494:pharmacology*; D010779:Photofluorography; D010957:Plasmids / Q000187:drug effects; D011500:Protein Synthesis Inhibitors / Q000494:pharmacology; D001618:beta-Lactamases / Q000096:biosynthesis* / Q000235:genetics
D000900:Anti-Bacterial Agents; D011500:Protein Synthesis Inhibitors; D008034:Lincomycin; D001618:beta-Lactamases; C034413:beta-lactamase TEM-1; C056342:beta-lactamase TEM-2