Hamada S, Tai S, Slade H D
Infect Immun. 1978 Jul;21(1):213-20. doi: 10.1128/iai.21.1.213-220.1978.
Lyophilized and heat-treated cells from the seven serotypes of Streptococcus mutans were examined for their ability to bind added insoluble-product glucosyl-transferase (GTase) and to synthesize cell-associated glucan from [(14)C]sucrose. Lyophilized cells of serotypes a and g did not synthesize any more additional glucan than did the controls after exposure to GTase. These cells, however, synthesized four- to eightfold-greater quantities of glucan than did the cells of the remaining serotypes. Lyophilized cells of serotypes b, c, d, e, and f synthesized two- to threefold-greater quantities of glucan after exposure to GTase than did the controls without added enzyme. Lyophilized cells of serotypes a and g synthesized 6- to 10-fold-greater quantities of glucan than did heat-treated cells of the same strain after binding of GTase. Lyophilized cells of the remaining serotypes synthesized only 1.6- to 3.3-fold-greater quantities of glucan than did the heat-treated cells. These results demonstrate that heat treatment to inactivate cell-associated GTase does not create additional GTase binding sites in S. mutans and that serotypes a and g are considerably more active in cell-associated glucan synthesis than cells of the other five serotypes. Ten species of gram-positive and gram-negative bacteria from five genera which do not produce in vitro plaque synthesized 10- to 100-fold-less glucan than did the S. mutans strains after exposure to GTase. Of these species, S. sanguis, Actinomyces viscosus, and A. naeslundii synthesized the largest quantities of glucan. Three mutant strains of S. mutans which possess a reduced ability for in vitro adherence but do agglutinate with glucan or dextran synthesized only one-third as much glucan after binding of GTase as the control. These results are discussed in relation to in vitro and in vivo plaque development and the agglutination of S. mutans. The results support earlier findings which indicate that the presence of bacterial species other than S. mutans in smooth-surface dental plaque is due in part to contact of the cells with glucan in the developing plaque and not to the binding of cell-free GTase and the in situ synthesis of glucan. The results obtained with these representative strains of the seven serotypes of S. mutans may not apply to the same extent to other strains within the serotypes.
对变形链球菌7种血清型的冻干和热处理细胞进行检测，以考察它们结合添加的不溶性产物葡糖基转移酶（GTase）以及从[¹⁴C]蔗糖合成细胞相关葡聚糖的能力。血清型a和g的冻干细胞在接触GTase后，合成的葡聚糖并不比对照组更多。然而，这些细胞合成的葡聚糖量比其余血清型的细胞多4至8倍。血清型b、c、d、e和f的冻干细胞在接触GTase后，合成的葡聚糖量比未添加酶的对照组多2至3倍。血清型a和g的冻干细胞在结合GTase后，合成的葡聚糖量比同一菌株的热处理细胞多6至10倍。其余血清型的冻干细胞合成的葡聚糖量仅比热处理细胞多1.6至3.3倍。这些结果表明，热处理使细胞相关GTase失活并不会在变形链球菌中产生额外的GTase结合位点，并且血清型a和g在细胞相关葡聚糖合成方面比其他5种血清型的细胞活跃得多。来自5个属的10种革兰氏阳性和革兰氏阴性细菌在体外不产生菌斑，在接触GTase后合成的葡聚糖比变形链球菌菌株少10至100倍。在这些菌种中，血链球菌、粘性放线菌和内氏放线菌合成的葡聚糖量最多。3株体外黏附能力降低但能与葡聚糖或右旋糖酐凝集的变形链球菌突变株在结合GTase后合成的葡聚糖仅为对照组的三分之一。结合体外和体内菌斑形成以及变形链球菌的凝集对这些结果进行了讨论。这些结果支持了早期的研究发现，即光滑表面牙菌斑中除变形链球菌外的其他细菌的存在部分是由于细胞与正在形成的菌斑中的葡聚糖接触，而不是由于无细胞GTase的结合和葡聚糖的原位合成。从变形链球菌7种血清型的这些代表性菌株获得的结果可能在相同程度上不适用于血清型内的其他菌株。
