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Staphylococcus aureus Produces Autolysin‐Susceptible Cell Walls during Growth in a High‐NaCl and Low‐Ca 2+ Concentration Medium
Author(s) -
Ochiai Toshiro
Publication year - 2000
Publication title -
microbiology and immunology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.664
H-Index - 70
eISSN - 1348-0421
pISSN - 0385-5600
DOI - 10.1111/j.1348-0421.2000.tb01252.x
Subject(s) - autolysin , autolysis (biology) , staphylococcus aureus , biology , cell wall , microbiology and biotechnology , biochemistry , bacteria , enzyme , peptidoglycan , genetics
The growth of Staphylococcus aureus 209P becomes unusually sensitive to a high‐NaCl concentration by decreasing the Ca 2+ concentration in growth media, and cells either autolyze or transform into protoplast‐like forms when grown standing in high‐NaCl and low‐Ca 2+ concentration media below 37 C (Ochiai, T., Microbiol. Immunol. 43 (7): 705–709, 1999). To assess the role of Ca 2+ in the salt tolerance of this organism, cells grown in the presence of different concentrations of Ca 2+ were treated with boiling SDS, and their susceptibilities to crude autolysin (3 M LiCl extract of S. aureus 209P cells) were evaluated by turbidimetric assay and zymographic analysis. Susceptibilities of SDS‐treated cells (SDS‐cells) to crude autolysin were significantly influenced by Ca 2+ concentration in the culture, and SDS‐cells prepared from cultures grown in high‐NaCl and high‐Ca 2+ concentration media exhibited marked resistance to crude autolysin when the assay system contained a high concentration of NaCl. On the contrary, SDS‐cells prepared from cultures grown in high‐NaCl and low‐Ca 2+ concentration media were rather susceptible to crude autolysin under the same assay conditions. A zymographic analysis revealed that the constitution of cell‐associated autolysins was not influenced by the concentration of exogenous Ca 2+ . These results suggested that at least part of the mechanism of salt‐induced autolysis in S. aureus 209P might be related to the synthesis of an autolysin susceptible cell wall.