Isolation and Characterization of Two Protease-Producing Mutants from Staphylococcus aureus

Abstract

Two mutants with increased protease production were isolated after nitrosoguanidine treatment of Staphylococcus aureus 8325N. The wild type produces low amounts of extracellular proteolytic activity. The enzyme was inducible and could only be detected if casein or preferably skim milk powder was used as inducer. The optimal pH, salt concentration, and media for enzyme production were determined. The mutants differed from the wild type in several phenotypic characters. The pattern of extracellular deoxyribonuclease and alkaline phosphatase differed between the mutants and the wild type. Several carbohydrates such as lactose, galactose, and mannitol were not utilized by the mutants, probably owing to a block in the uptake. Glucose could, however, be utilized by the mutants. Reversion frequency to wild type with regard to carbohydrate utilization was spontaneously high, and all revertants regained the parental pattern irrespective of the carbohydrate used for selection. The results suggest that a single locus may control the excretion of extracellular enzymes and carbohydrate uptake in S. aureus.

Cloning, sequencing and expression of subtilisin Carlsberg fromBacillus licheniformis

“…Immune diffusion analysis was according to Ouchterlony (23). The presence of extracellular proteases was detected on milk agarose plates (24). SDS-polyacrylamide gels (25) were used to analyze the gene products.…”

Hyperproduction of Extracellular Protease in Mutants of Vibrio parahaemolyticus

“…Repression of protease production by either protein hydrolysates or amino acid mixtures was also reported for other bacteria (1, 5, 6), but the mechanism of the repression has been completely obscure. Hyperprotease-producing mutants have been described for Bacillus subtilis (6), B. cereus (6) and Staphylococcus aureus (7). Whether these mutants are related to ours, however, remains to be clarified.…”

The functional characterisation of soybean (Glycine max L.) rhizospheric bacteria indigenous to Ethiopian soils

“…To test for cellulase, chitinase and protease activity, each rhizobacterial isolate (10 µl; 10 6 cells ml -1 ) was spot-inoculated on Carboxymethyl cellulose (CMC) agar plates (Kasana et al, 2008), chitin agar (Bansode and Bajekal, 2006) and NA plates supplemented with 1.5% [w/v] skimmed milk powder (Ryden et al, 1973), respectively. The plates were incubated at 28°C for 72 h and the "clear" zone formation of their colonies was recorded as indication of enzyme activity.…”