pubmed-article:6581522 | pubmed:abstractText | Bacteroides sp. was isolated in human periapical osteitis and shown to be biochemically closely related to B. ruminicola ssp. brevis and B. capillus. Electron microscopic examination revealed an external cell-wall layer (S-layer). The fractionation of cells by various methods gave partially purified sheets corresponding to the observed layer with a hexagonal molecular arrangement. | lld:pubmed |