Clark W B, Gibbons R J
Infect Immun. 1977 Nov;18(2):514-23. doi: 10.1128/iai.18.2.514-523.1977.
The adsorption of (3)H-labeled Streptococcus mutans 6715 cells to disks of hydroxyapatite (HA) was studied. The number of streptococci that adsorbed was logarithmically related to the concentration of cells available up to at least 2 x 10(8) per ml; equilibrium occurred within 45 min. Assay reliability was verified by direct scanning electron microscopic counts. Untreated HA disks exposed to buffered saline (PBS)-suspended streptococci at a concentration of 1.1 x 10(8) per ml absorbed 3.2 x 10(6) cells per cm(2); approximately 3% of the surface area was, therefore, occupied by adsorbed organisms. The presence of adsorbed salivary components on HA reduced the number of attaching S. mutans cells by half. When S. mutans cells were suspended in saliva to mimic conditions existing in the mouth, the number of streptococci adsorbing to saliva-treated HA was reduced more than 30-fold compared to untreated HA. Approximately one-half of the streptococci adsorbed to untreated or to saliva-treated HA disks could be desorbed over a 4-h period with 0.067 M phosphate buffer. S. mutans cells exposed to sucrose to permit extracellular polysaccharide synthesis before or during adsorption attached in fewer numbers to both saliva-treated and untreated HA than PBS-treated organisms. When S. mutans cells adsorbed on untreated HA were exposed to sucrose, fewer organisms could be desorbed; thus, in situ polysaccharide synthesis promoted their more firm attachment to untreated HA. However, when saliva-suspended streptococci were adsorbed to saliva-treated HA surfaces, exposure to sucrose before or subsequent to adsorption did not promote more firm attachment. Evidently, the powerful adherence-inhibiting and desorptive effects of salivary components overshadowed any promoting effects attributable to glucan synthesis from sucrose. Similarly, no differences were noted in the desorption of S. mutans cells from human teeth after exposure to sucrose, glucose, or PBS relative to a strain of Streptococcus mitis (S. mitior). Thus, no evidence was obtained to support the hypothesis that glucan synthesis from sucrose was essential for, or promoted, the attachment of S. mutans cells to HA surfaces exposed to saliva or to the smooth surfaces of human teeth.
研究了（3）H标记的变形链球菌6715细胞对羟基磷灰石（HA）盘的吸附。吸附的链球菌数量与每毫升至少可达2×10（8）个的可用细胞浓度呈对数关系；45分钟内达到平衡。通过直接扫描电子显微镜计数验证了检测的可靠性。暴露于浓度为每毫升1.1×10（8）个的磷酸盐缓冲盐水（PBS）悬浮链球菌的未处理HA盘每平方厘米吸附3.2×10（6）个细胞；因此，约3%的表面积被吸附的生物体占据。HA上吸附的唾液成分的存在使附着的变形链球菌细胞数量减少一半。当变形链球菌细胞悬浮在唾液中以模拟口腔中的现有条件时，与未处理的HA相比，吸附到唾液处理过的HA上的链球菌数量减少了30多倍。在4小时内，用0.067M磷酸盐缓冲液可使吸附到未处理或唾液处理过的HA盘上的约一半链球菌解吸。在吸附前或吸附过程中暴露于蔗糖以允许细胞外多糖合成的变形链球菌细胞，与PBS处理的生物体相比，附着到唾液处理和未处理的HA上的数量都较少。当吸附在未处理HA上的变形链球菌细胞暴露于蔗糖时，可解吸的生物体较少；因此，原位多糖合成促进了它们与未处理HA的更牢固附着。然而，当唾液悬浮的链球菌吸附到唾液处理过的HA表面时，吸附前或吸附后暴露于蔗糖都不会促进更牢固的附着。显然，唾液成分强大的粘附抑制和解吸作用掩盖了蔗糖合成葡聚糖的任何促进作用。同样，相对于缓症链球菌（轻链球菌）菌株，暴露于蔗糖、葡萄糖或PBS后，变形链球菌细胞从人牙齿上的解吸没有差异。因此，没有证据支持这样的假设，即蔗糖合成葡聚糖对于变形链球菌细胞附着到暴露于唾液的HA表面或人牙齿的光滑表面是必不可少的或有促进作用。
