5-methyltryptophan (5MT) induces penicillinase synthesis in Staphylococcus aureus. The analog is incorporated into protein by both wild-type and tryptophan-starved cells. Since normal penicillinase repressor appears to contain tryptophan even though penicillinase itself does not, it is concluded that 5MT induces penicillinase synthesis by becoming incorporated into the penicillinase repressor a...

The cloned gene coding for Bacillus licheniformis penicillinase (penP) was introduced into Escherichia coli in a heat-inducible lambda Qam vector. After induction, significant amounts of penicillinase were synthesized in the new host. The cellular location of the penicillinase was found to be almost exclusively the outer membrane fraction of E. coli, and virtually no soluble penicillinase was f...

L-phase variants and small colony (G-phase) variants derived from penicillinase-producing Staphylococcus aureus strains were tested for penicillinase (beta lactamase) production. A refined variation of the modified Gots test for penicillinase was used to demonstrate penicillinase synthesis. Penicillinase synthesis was reduced in L-phase variants and G-phase variants when compared to parental st...

Penicillinase-producing strains of Staphylococcus aureus are transformed into stable L colonies by 70 to 100 subcultures on methicillin-containing medium with a suitable high osmolarity. During transformation, the penicillinase activity is lost. This loss in activity is not the result of only the penicillinase-negative mutants transforming to L colonies. If unstable L colonies are filtered thro...

Previously described penicillinase-constitutive mutations in Staphylococcus aureus are caused by genetic lesions in a regulator gene (or genes) on the penicillinase plasmid in close linkage to the structural gene. This report describes a new class (R2(-)) of penicillinase-constitutive mutants of S. aureus unlinked to the plasmid. By transductional analysis, the penicillinase plasmids in these m...

Two hundred and thirty-nine penicillinase-positive and 240 penicillinase-negative strains of Neisseria gonorrhoeae were tested for their susceptibility to cefotaxime. All were susceptible to cefotaxime at a concentration of 0.062 micrograms/ml. Penicillinase-negative strains were less susceptible than penicillinase-positive strains. This is attributed to the use of prophylactic antibiotics by p...

Penicillinase activity was found in commercial samples of Limburger, Liederkranz, and Brick, as well as in Roquefort and Danish Blue cheeses. The numbers of penicillinase-producing bacteria in the cheese flora were estimated by use of the most probable numbers technique coupled with penicillinase determinations on the individual cultures. Although streptococci constituted the predominant flora ...

Protoplasis of Bacillus licheniformis 749/C (a mutant constitutive for penicillinase production) continued to synthesize and release penicillinase in hypertonic growth medium in the presence of trypsin and chymotrypsin at 25 mug each per ml. When the protoplasts were stripped of about half of their membrane-bound penicillinase by pretreatment at pH 9.5 or with a higher level of trypsin, penicil...

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 p...

The fluorescent antibody test is now widely used to confirm the identity of Neisseria gonorrhoeae but may fail to identify penicillinase-producing strains (PPNG). This problem arises when conjugates are used that incorporate only gonococci that are not penicillinase-producers. We have shown that conjugates prepared from mixtures of PPNG and non-penicillinase producing gonococci give good fluore...