| The ultrastructure, growth characteristics, outer membrane biochemistry, and biological activities of outer membrane components of the potential periodontopathogen, Eikenella corrodens, were studied. Electron microscopic observation of the type strain, ATCC 23834, and two periodontal disease isolates showed a typical Gram-negative cell envelope structure. Ruthenium red staining, alcian blue staining, heavy metal shadow-casting, and scanning electron microscopy revealed the presence of an extracellular slime layer.; The development of a liquid medium (containing salts, KNO(,3), hemin, and yeast extract) capable of supporting good growth of E. corrodens strains, allowed the study of parameters of Eikenella growth. Growth was found to be optimal in either a 10% CO(,2) + air or 100% air atmosphere while growth in an anaerobic atmosphere was less than optimal. Nutritionally, E. corrodens strain 23834 appears to require nitrate and one or more factors present in yeast extract for growth.; The purified outer membrane fractions (OMFs) were predominantly protein (69%) with 10% lipid. SDS-PAGE analysis revealed one major peptide of 33,500 dal in strain 23834 and 37,500 dal in strain 470 OMFs. The lipopolysaccharide (LPS) was found to contain lipid, carbohydrate, no hydroxy fatty acids, and only trace amounts of heptose and 2-keto-3-deoxyoctonate.; Despite a nonclassical LPS structure, the Eikenella LPS retained classical LPS biological activities, including mitogenicity, limulus lysate clotting, and bone resorption. The OMFs were also active in these assays. It thus appears that E. corrodens is well "equipped" to function as a major factor in periodontal tissue necrosis. |
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