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INFLUENCE OF OSMOTIC PRESSURE ON TRANSFORMABLE AND NON TRANSFORMABLE VARIANTS OF NEISSERIA MENINGITIDIS
Author(s) -
JYSSUM KAARE
Publication year - 1975
Publication title -
acta pathologica microbiologica scandinavica section b microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.909
H-Index - 88
eISSN - 1600-0463
pISSN - 0304-131X
DOI - 10.1111/j.1699-0463.1975.tb00099.x
Subject(s) - lysis , spheroplast , osmotic pressure , tonicity , osmotic shock , erythrocyte fragility , plasmolysis , neisseria meningitidis , cytolysis , membrane , strain (injury) , chemistry , biophysics , cell wall , biochemistry , microbiology and biotechnology , biology , bacteria , hemolysis , in vitro , immunology , escherichia coli , genetics , cytotoxicity , anatomy , gene
Penicillin spheroplasts from competent ( cp + ) and incompetent ( cp ‐ ) variants of Neisseria meningitidis Strain M1 were equally fragile as determined by the osmotic strength necessary for stabilization. Exponential phase cells adapted to growth under increased osmotic pressure and suspended in acetate or phosphate became osmotically fragile within 2–4 hours when stabilized by sucrose plus MgCl 2 . Spheroplasts were formed during the succeeding 6–12 hours. Cells that were not adapted to growth at high tonicity but exposed to the stabilizing fluid under conditions leading to plasmolysis, developed osmotic fragility more rapidly, but at the same time lysis of the membranes was activated. Under these conditions, membrane lysis occurred far more rapidly in the cp ‐ variant than in the cp + variant. Membrane lysis was inhibited by MgCl 2 and enhanced by CaCl 2 in low concentration. The findings support the notion that osmotic stress in N. meningitidis activates membrane lysis as well as cell wall lysis, and that both activations are far more pronounced in the cp ‐ variant. But the relative protection of the cp + variant cannot be due to higher tensile strength of the membranes.