Nesbitt W E, Doyle R J, Taylor K G, Staat R H, Arnold R R
Infect Immun. 1982 Jan;35(1):157-65. doi: 10.1128/iai.35.1.157-165.1982.
The adherence of Streptococcus sanguis to hydroxylapatite beads has been analyzed by binding isotherms, Langmuir isotherms, and Scatchard plots. For saliva-coated beads, the Scatchard curves contained components with both positive and negative slopes. The results are interpreted as evidence for positive cooperativity in the binding process. Although all Scatchard curves were similar in shape, distinct differences were observed between saliva samples from different individuals. Salivary agglutinins against whole S. sanguis cells did not appear to influence the shapes of the curves or the extent of adherence. In addition, different strains of S. sanguis yielded similar Scatchard plots. When the binding of S. sanguis to buffer-coated hydroxylapatite beads was analyzed by Scatchard plots or binding isotherms, curves were generated which suggested that either direct ligand-ligand or nonspecific interactions were occurring. Hill plots of the adherence data yielded curves with slopes greater than unity for saliva-coated beads, providing additional support for the view that the interactions between S. sanguis and the pellicle involve cooperative phenomena. In contrast, a Hill plot for the binding data of S. sanguis to buffer-coated hydroxylapatite beads gave a curve with a slope of 0.91 +/- 0.07, suggesting negative cooperativity or limited specificity. When adherence data were plotted by the Langmuir method, curves were obtained which could not discriminate between the binding of the bacteria to the hydroxylapatite beads coated with either saliva or buffer. It was also observed that several different proteins and whole saliva tended to inhibit adherence. Scatchard plots, however, describing the binding of S. sanguis to the proteincoated beads were unique and revealed possible specific and nonspecific interactions. Scatchard analyses of binding data may be useful in understanding the mechanism(s) of adherence of streptococci to smooth surfaces.
通过结合等温线、朗缪尔等温线和斯卡查德图分析了血链球菌对羟基磷灰石珠的黏附情况。对于唾液包被的珠子，斯卡查德曲线包含具有正斜率和负斜率的成分。结果被解释为结合过程中存在正协同作用的证据。尽管所有斯卡查德曲线形状相似，但不同个体的唾液样本之间观察到明显差异。针对全血链球菌细胞的唾液凝集素似乎不影响曲线形状或黏附程度。此外，不同菌株的血链球菌产生相似的斯卡查德图。当通过斯卡查德图或结合等温线分析血链球菌与缓冲液包被的羟基磷灰石珠的结合时，生成的曲线表明发生了直接配体-配体或非特异性相互作用。唾液包被珠子的黏附数据的希尔图产生的曲线斜率大于1，为血链球菌与获得性膜之间的相互作用涉及协同现象的观点提供了额外支持。相比之下，血链球菌与缓冲液包被的羟基磷灰石珠的结合数据的希尔图给出的曲线斜率为0.91±0.07，表明存在负协同作用或有限的特异性。当用朗缪尔方法绘制黏附数据时，得到的曲线无法区分细菌与唾液或缓冲液包被的羟基磷灰石珠的结合。还观察到几种不同的蛋白质和全唾液倾向于抑制黏附。然而，描述血链球菌与蛋白质包被珠子结合的斯卡查德图是独特的，揭示了可能的特异性和非特异性相互作用。结合数据的斯卡查德分析可能有助于理解链球菌黏附于光滑表面的机制。
