Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “PENICILLINASE”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 55 records · Page 3Linked to original sources
PubMed1975

[Specific and nonspecific factors that influence the transduction of genetic determinants for penicillinase activity and pathogenicity in Staphylococcus aureus. III. The prevention of the transduction of penicillinase determinants by acridine derivatives].

In comparing the antitransducing activity of the acridine derivatives there was revealed a relationship between their chemical structure (the degree of substitution of position 9), the capacity to depress the lytic activity of staphylophages and the action in respect to the transducing particles of the donor lysate.

Acridines↗
PubMed1969

Characteristics of penicillinase secretion by growing cells and protoplasts of Bacillus licheniformis.

Cultures of the inducible penicillinase-producing strain 749 of Bacillus licheniformis, induced with small amounts of benzylpenicillin, synthesized penicillinase at a high rate for a short period, after which the rate of synthesis slowly declined. During the period of active synthesis, the rate of secretion, as a fraction of the level of cell-bound penicillinase (which is originally high), gradually decreased to a constant level. Chloramphenicol, at a concentration (40 mug/ml) which completely inhibited synthesis of penicillinase, partially inhibited secretion if added during the period of active synthesis. During the phase of reduced synthesis, chloramphenicol was without effect on secretion. Penicillinase secretion, by actively growing cultures of the constitutive penicillinase-producing mutant 749/C, was inhibited by 75% immediately after addition of chloramphenicol. The secretion of part of the penicillinase released during active growth is probably dependent on synthesis of penicillinase, but part of the secreted penicillinase can be released in the absence of synthesis. Protoplasts were obtained from which periplasmic penicillinase has been removed, and these protoplasts were capable of substantial growth and penicillinase synthesis without lysis. At pH 7.5, there was no net incorporation of penicillinase into the cell membrane; the enzyme released was almost entirely of the exo form and was roughly equivalent to the amount of new enzyme formed. At pH 6.0, there was some incorporation of penicillinase into the plasma membrane, and approximately half of the extracellular penicillinase was in the exo form; the remainder perhaps represented membrane fragments. In the presence of chloramphenicol, a small amount of penicillinase was released at pH 7.5 as the exo form; at pH 6.0, practically none was released. We suggest that, with the removal from protoplasts of the periplasmic penicillinase-containing particles, a restriction on secretion has been lifted.

Bacillus↗
PubMed1973

Repressor and antirepressor in the regulation of staphylococcal penicillinase synthesis.

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 and thereby inactivating the repressor. Thus biochemical data support the existence of a penicillinase repressor and indicate that penicillinase synthesis is regulated by negative control and not by positive control.-In the absence of exogenous tryptophan, staphylococcal penicillinase induction can be inhibited by 7-azatryptophan (7azaT). Because 7azaT is incorporated into protein by tryptophan-starved cells, it is concluded that 7azaT blocks penicillinase induction by inactivating a penicillinase regulatory protein into which the analog has been incorporated. Incorporation of 7azaT does not appear to inactivate the operator binding site or the effector binding site on the penicillinase repressor. Therefore, it appears that 7azaT blocks penicillinase induction by inactivating the penicillinase antirepressor, a protein required for inactivation of the penicillinase repressor and, hence, required for penicillinase induction.

Aza Compounds↗
PubMed1972

Regulation of staphylococcal penicillinase synthesis.

5-Methyl tryptophan was found to be an efficient inducer of penicillinase synthesis in Staphylococcus aureus. Addition of actinomycin D or tryptophan to the culture medium shuts off the 5-methyl tryptophan-induced synthesis of penicillinase with an apparent half-life of approximately 1 to 2 min, respectively. Hence, in the induction of penicillinase synthesis, 5-methyl tryptophan seems to function as a structural analogue of penicillin rather than by becoming incorporated in proteins and thereby creating faulty penicillinase repressor or antirepressor. This conclusion is supported by similarities in the structures of the two compounds as revealed by solid atomic models. The fact that S. aureus exposed to (14)C-penicillin in the absence of protein synthesis failed to synthesize penicillinase at an increased level when cell growth was resumed strongly suggests that a protein involved in the regulation of penicillinase synthesis must be synthesized in the presence of the penicillinase inducer. In turn, this observation suggests that the penicillinase inducer promotes penicillinase synthesis by directing the penicillinase regulatory protein (i.e., the penicillinase antirepressor) to acquire a different conformation when it is synthesized in the presence of the penicillinase inducer. A working model for the regulation of penicillinase synthesis based on these and other data has been constructed and is presented.

Bacterial Proteins↗