New Assay for Penicillinase and Some Results on Penicillinase Induction.

Imsande, John (Western Reserve University, Cleveland, Ohio). New assay for penicillinase and some results on penicillinase induction. J. Bacteriol. 89:1322-1327. 1965.-A rapid, sensitive, and reliable assay of penicillinase activity is described. Studies conducted on the induction of penicillinase, with use of the new assay, show that actinomycin D inhibits growth and the induced synthesis of penicillinase in Bacillus cereus 569. These inhibitory effects can be reversed to various degrees by deoxyguanosine, depending upon the time lapse between the addition of the antibiotic and the addition of the deoxynucleoside. Inhibition of growth is reversed more readily than inhibition of penicillinase induction, and it is suggested that actinomycin D may preferentially inhibit the induced synthesis of penicillinase. Studies conducted in an attempt to ascertain the role of penicillin in inducing penicillinase formation in B. cereus 569 suggest that the inducer, penicillin, enhances penicillinase synthesis in some manner in addition to its probable role of inducing the formation of a penicillinase-specific ribonucleic acid messenger.