A protease with staphylolytic activity from Pseudomonas aeruginosa PAKS I.

The supernatant from broth cultures of Pseudomonas aeruginosa PAKS I contains two different enzymes with staphylolytic activity. One of them, namely staphylolytic enzyme, seems to be specific for glycine-rich cross-links present in the cell wall of different Gram-positive bacteria and has been previously characterized. In addition to the staphylolytic activity, the second protein which we propose to be a staphylolytic protease, has proteolytic activity against casein. This enzyme is approximately 33 kDa, has an isoelectric point ranging from 7.3 to 8.1 and an optimum pH value of 8.0 for casein hydrolysis. Staphylolytic protease was detected in the extracellular medium after 12 h of cell growth. Immunocytochemical studies suggest that the protease is located within the periplasmic space of P. aeruginosa.

Staphylolytic enzyme from Pseudomonas aeruginosa: characterization and immunocytochemical localization.

Staphylolytic enzyme, a specific peptidase produced by Pseudomonas aeruginosa, has been characterized by using immunochemical procedures. Lytic activity was detected in the extracellular medium of Pseudomonas cultures at the beginning of the stationary growth phase. No activity was detected in bacterial cells. However, lytic protein antigen was present in periplasmic and cytoplasmic fractions, suggesting that staphylolytic enzyme is synthesized as an inactive precursor which becomes active during translocation to the extracellular broth. Results obtained in immunolocalization experiments indicate the presence of the precursor in the outer part of cells. The export pathway of staphylolytic enzyme through the periplasmic space is proposed.

L-form-like colonies of Staphylococcus aureus induced by an extracellular lytic enzyme from Pseudomonas aeruginosa.

An extracellular enzyme produced by Pseudomonas aeruginosa had a lytic effect on lyophilized Staphylococcus aureus cells. It was purified from the culture supernatant by ammonium sulfate fractionation followed by column chromatography with P cellulose and Sephadex G-50. The molecular weight of the enzyme was estimated to be 19,000 +/- 1,750 with sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The pI of the enzyme was estimated to be 8.5 with isoelectric focusing. The enzyme was inactive in 4% NaC1-40 mM sodium phosphate buffer or at pH values lower than 6.0 or higher than 11.0; however, it was not affected by 1 M sucrose or 0.25% heat-denatured horse serum. The action of the enzyme on cultures of S. aureus resulted in the presence of many cells lacking cell walls. In addition, when cultivation was carried out on osmotically stabilized solid media, these cell wall-deficient cell developed in L-form colonies.

Purification and peptidase activity of a bacteriolytic extracellular enzyme from Pseudomonas aeruginosa.

A bacteriolytic enzyme excreted by Pseudomonas aeruginosa Paks I was purified: samples were found to be homogeneous by gel filtration chromatography, ion exchange chromatography using CM-cellulose, immunoelectrophoresis, PAGE and SDS-PAGE. The molecular weight of the lytic enzyme was estimated to be 15,000-19,000. The enzyme was active on Gram-positive bacteria with glycine-containing interpeptide bridges in their murein layers. In addition, this lytic enzyme showed peptidase activity catalysing the hydrolysis of pentaglycine peptides into tri- and diglycine peptides.

Effects of staphylolytic enzymes from Pseudomonas aeruginosa on the growth and ultrastructure of Staphylococcus aureus.

Pseudomonas aeruginosa produces two extracellular staphylolytic enzymes able to lyse Staphylococcus aureus cells when they are added to liquid cultures of S. aureus. In addition, when cultivation was carried out in the presence of both lytic enzymes and 1 M sucrose, the staphylococci either lacked cell walls or showed damaged walls. Lytic activity-resistant cells of S. aureus were also detected.