Cowan M M, Taylor K G, Doyle R J
Infect Immun. 1987 Jul;55(7):1552-7. doi: 10.1128/iai.55.7.1552-1557.1987.
Evaluation of the kinetics of adhesion of Streptococcus sanguis 10556 to saliva-coated hydroxylapatite revealed that sialic acid played a role in the formation of a stable cell-substratum complex. In a previous paper (M. M. Cowan, K. G. Taylor, and R. J. Doyle, J. Dent. Res. 65:1278-1283, 1986) the adhesion was found to take place in two distinct stages: a reversible equilibrium, probably governed by long-range forces, followed by a transition to higher-affinity binding. In the present study, artificial pellicle was treated with neuraminidase, and kinetic adsorption and desorption experiments with S. sanguis were conducted. The depletion of sialic acid from pellicle decreased the initial adsorption rate constant only slightly. The rate constant describing the initial desorption was unaffected. However, no transition to the second (high-affinity) association occurred. While S. sanguis desorption from control pellicles exhibited two sequential rates, with the second rate being approximately 10 times slower than the first, all desorption from sialo-deficient pellicles occurred at one rate that was equivalent to the initial rate constant for control desorption. The cells did not reach an equilibrium with the sialo-deficient pellicle, even after 6 h. Competing sialic acid did not decrease the rate or extent of adsorption, but desorption occurred to a greater extent when cells had adsorbed in the presence of sialic acid. These data suggest that sialic acid plays little role in the initial association of cell and pellicle but that it is necessary for the transition to high-affinity binding and the concomitant decreased propensity to desorb.
对血链球菌10556与唾液包被的羟基磷灰石的黏附动力学评估显示，唾液酸在稳定的细胞-基质复合物形成中发挥作用。在之前的一篇论文（M. M. Cowan、K. G. Taylor和R. J. Doyle，《牙科研究杂志》65:1278 - 1283，1986）中发现，黏附过程分两个不同阶段发生：一个可逆平衡，可能由长程力控制，随后转变为高亲和力结合。在本研究中，用人神经氨酸酶处理人工获得性膜，并进行了血链球菌的动力学吸附和解吸实验。从获得性膜中去除唾液酸仅使初始吸附速率常数略有降低。描述初始解吸的速率常数未受影响。然而，未发生向第二个（高亲和力）结合阶段的转变。虽然从对照获得性膜上解吸血链球菌呈现两个连续速率，第二个速率比第一个速率慢约10倍，但从缺乏唾液酸的获得性膜上的所有解吸都以与对照解吸的初始速率常数相当的一个速率发生。即使在6小时后，细胞与缺乏唾液酸的获得性膜也未达到平衡。竞争性唾液酸并未降低吸附速率或程度，但当细胞在唾液酸存在下吸附时，解吸程度更大。这些数据表明，唾液酸在细胞与获得性膜的初始结合中作用不大，但对于向高亲和力结合的转变以及随之而来的解吸倾向降低是必要的。
