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M M McCabe

Publications and source records attributed to M M McCabe.

29 records · Page 2Linked to original sources
PubMed1975

Relationship between cell-bound dextransucrase and the agglutination of Streptococcus mutans.

Dextran-induced agglutination of Streptococcus mutans cells is independent of cell-bound dextransucrase activity. Toluene extraction or the presence of Hg2+ or Cu2+ markedly decreased or completely abolished cell-bound dextransucrase activity without adversely affecting dextran-induced cell agglutination. Cells treated by heating at 100 C until cell-bound dextransucrase was completely inactivated continued to agglutinate when induced by dextran-induced cell agglutination resulted from cell treatment with trypsin and several other enzymes, as well as from ethylenediaminetetraacetic acid treatment, without a corresponding loss of cell-bound dextransucrase activity. Cells possessed a greater avidity for branched dextrans of low molecular weight than for linear dextrans of the same weight, indicating that size alone does not determine the efficiency of dextran as an inducer of agglutination. Divalent metal ions were required for both sucrose- and dextran-induced agglutination of S. mutans K1-R cells. Although normal cells of strain 6715-49 did not appear to require divalent cations for agglutination, heat- and ethlyenediaminetetraacetic acid-treated cells specifically required Ca2+. The role of Ca2+ in cell agglutination may be either to activate the cell-surface dextran receptor or to form specific intercellular Ca2+ bridges.

Agglutination↗
PubMed1973

Origin of the cell-associated dextransucrase of Streptococcus mutans.

The cell-associated dextransucrase produced by sucrose-grown cells of cariogenic Streptococcus mutans K1-R is derived from soluble dextransucrase. Synthesis of insoluble dextran by soluble dextransucrase gives rise to two dextransucrase fractions bound to the insoluble polysaccharide; a reversibly bound enzyme, which can be eluted in solutions of clinical dextran, and an irreversibly bound enzyme, which cannot be solubilized in this manner. Both of these fractions of dextransucrase are also present on sucrose-grown cells. During the synthesis of insoluble dextran by sucrose-grown cells, dextransucrase is progressively converted from soluble enzyme, first to the reversibly bound fraction and then to the irreversibly bound fraction, and is finally inactivated as insoluble dextran accumulates. The two cell-associated dextransucrase fractions therefore represent two stages in the insolubilization and inactivation of their precursor, soluble dextransucrase. As a result of this process of inactivation, the yield of dextransucrase from cells cultured on sucrose is markedly decreased by high concentrations of sucrose in the culture medium.

Cariogenic Agents↗
PubMed1970

Actinomycosis.

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Actinomycosis↗