Antigenic and biochemical characteristics of Mobiluncus mulieris and Mobiluncus curtisii

Twenty-four strains of Mobiluncus mulieris and 27 strains of Mobiluncus curtisii were tested with respect to 6 different biochemical characteristics: arginin-decarboxylase activity, beta-galactosidase activity, synergistic hemolysis with Staphylococcus aureus, hydrolysis of hippurate, migration through soft agar and reduction of nitrate. Antigens of the same strains, prepared by ultrasonication, were subjected to sodium dodecyl sulphate-polyacrylamide gel electrophoresis followed by immunoblotting using polyclonal rabbit antisera against two of the M. mulieris strains and five of the M. curtisii strains. Two different strongly reacting protein antigens could be detected in the M. mulieris strains. These strains could be separated into three groups based on the possession of either of the two antigens or both. In the M. curtisii strains, 10 strongly reacting protein antigens could be detected. Four strains possessed only one of these antigens, one did not possess any, while the remaining strains possessed different sets of 9 of them. Within each species common protein antigens were detected. No antigens were found which were shared by both species. The biochemical characteristics studied could not differentiate between the antigenic groups in any of the species. None of the antigenic subgroups of M. curtisii found in the present study was identical with any of the two subspecies (curtisii and holmesii) which have been proposed.