Effects of temperature on the autolytic enzyme system of Streptococcus faecalis

Abstract

The cellular autolytic reaction system in Streptococcus faecalis ATCC 9790 was analyzed for relative increases in reaction rates with increasing temperature by determination of Arrhenius activation energies (E). The systems examined were: (i) an isolated wall-enzyme complex in 0.01 M sodium phosphate, pH 6.9; (ii) exponential-phase cells suspended in 0.01 or 0.3 M sodium phosphate, pH 6.8, or in 0.04 M ammonium acetate, pH 6.8; (iii) growing cultures deprived of glucose or lysine; and (iv) cultures treated in growth media with the nonionic detergent, Triton X-100. For detergent-treated cells, E values were between 23.9 and 27.4 kcal/mol (ca. 100.1 to 174.7 kJ/mol) at concentrations of Triton X-100 between about 0.03 and 0.072 mg/ml. E values dropped sharply to 11.5 to 13.0 kcal/mol (ca. 48.2 to 54.4 kJ/mol) at Triton X-100 concentrations of 0.12 mg/ml or higher. For the remaining systems, E values ranged from 16 to 20 kcal/mol (ca. 67.0 to 83.7 kJ/mol) (wall lysis, cellular autolysis in 0.01 M sodium phosphate or in 0.04 M ammonium acetate, and autolysis of glucose-starved cells) to 31 to 38 kcal/mol (ca. 129.8 to 159.1 kJ/mol) (cellular autolysis in 0.3 M sodium phosphate or autolysis of lysine-starved cells). High concentrations of Triton X-100 appear to

Use of resistant mutants to study the interaction of triton X-100 with Staphylococcus aureus

“…Autolysins have been implicated in Triton X-100-induced lysis of S. faecium (12,19) and deoxycholate-induced lysis of Streptococcus pneumoniae (32), and we therefore studied Triton X-100-resistant mutants isolated from both wild-type and Lyt-strains of S. aureus. Our results show that Triton X-100-resistant mutants can grow and divide in broth containing 5% Triton X-100, while growth of the parental strains is markedly inhibited above the critical micellar concentration (0.02%) of the detergent.…”