Surface characteristics of Wolinella recta ATCC 33238 and human clinical isolates: correlation of structure with function

Abstract

Selected characteristics of the surface of Wolinella recta ATCC 33238 and three W. recta clinical isolates (CI) were studied as well as the adherence of these strains to human gingival fibroblasts (HGF). W. recta ATCC 33238 and the CI were examined by electron microscopy, electrophoresis, isoelectric focusing, and adherence to HGF. Electron microscopic examination of CI revealed the presence of a periodic paracrystalline layer external to and associated with the outer membrane. This surface layer (S layer) was not observed on ATCC 33238. Whole cells and outer envelope protein profiles of the CI revealed major bands of 159- to 138-kilodalton proteins which were barely detectable in ATCC 33238. Repeated in vitro subculturing of the CI on solid or liquid medium resulted in both the physical loss of this layer and the loss of the high-molecular-weight proteins. Low-passage-number CI demonstrated 40 to 60% less adherence to HGF than ATCC 33238. These observations suggest that short term in vitro-subcultured W. recta strains possess surface characteristics which are significantly different from those of their long-term in vitro-subcultured counterparts. These differences may have significant effects on host cell interactions.