van der Mei H C, Busscher H J
Laboratory for Materia Technica, University of Groningen, The Netherlands.
Adv Dent Res. 1997 Nov;11(4):388-94. doi: 10.1177/08959374970110040301.
Physicochemical and structural properties of microbial cell surfaces play an important role in their adhesion to surfaces and are determined by the chemical composition of the outermost cell surface. Many traditional methods used to determine microbial cell wall composition require fractionation of the organisms and consequently do not yield information about the composition of the outermost cell surface. X-ray photoelectron spectroscopy (XPS) measures the elemental composition of the outermost cell surfaces of micro-organisms. The technique requires freeze-drying of the organisms, but, nevertheless, elemental surface concentration ratios of oral streptococcal cell surfaces with peritrichously arranged surface structures showed good relationships with physicochemical properties measured under physiological conditions, such as zeta potentials. Isoelectric points appeared to be governed by the relative abundance of oxygen- and nitrogen-containing groups on the cell surfaces. Also, the intrinsic microbial cell-surface hydrophobicity by water contact angles related to the cell-surface composition as by XPS and was highest for strains with an elevated isoelectric point. Inclusion of elemental surface compositions for tufted streptococcal strains caused deterioration of the relationships found. Interestingly, hierarchical cluster analysis on the basis of the elemental surface compositions revealed that, of 36 different streptococcal strains, only four S. rattus as well as nine S. mitis strains were located in distinct groups, well separated from the other streptococcal strains, which were all more or less mixed in one group.
微生物细胞表面的物理化学和结构特性在其对表面的黏附中起着重要作用，并且由最外层细胞表面的化学成分决定。许多用于确定微生物细胞壁组成的传统方法需要对生物体进行分级分离，因此无法获得有关最外层细胞表面组成的信息。X射线光电子能谱（XPS）可测量微生物最外层细胞表面的元素组成。该技术需要对生物体进行冷冻干燥，不过，具有周生排列表面结构的口腔链球菌细胞表面的元素表面浓度比与在生理条件下测量的物理化学性质（如zeta电位）显示出良好的关系。等电点似乎由细胞表面含氧化合物和含氮化合物的相对丰度决定。此外，通过水接触角测量的微生物细胞表面固有疏水性与通过XPS测得的细胞表面组成有关，对于等电点升高的菌株，其疏水性最高。纳入丛生链球菌菌株的元素表面组成会导致所发现关系的恶化。有趣的是，基于元素表面组成的层次聚类分析表明，在36种不同的链球菌菌株中，只有4株大鼠链球菌以及9株缓症链球菌位于不同的组中，与其他链球菌菌株明显分开，而其他链球菌菌株或多或少混合在一组中。
