Desulfovibrio africanus sp. n., a New Dissimilatory Sulfate-reducing Bacterium

Abstract

Campbell, L. Leon (University of Illinois, Urbana), Mary A. Kasprzycki, and John R. Postgate . Desulfovibrio africanus sp. n., a new dissimilatory sulfate-reducing bacterium. J. Bacteriol. 92: 1122–1127. 1966.—The strains Benghazi and Walvis Bay can be distinguished from 40 strains of Desulfovibrio and from D. gigas on the basis of morphological and immunological studies. Electron microscopy revealed polar lophotrichous flagellation similar to that of D. gigas but different from the characteristic single polar flagellum of the 40 strains of Desulfovibrio . Immunological evidence shows that the two strains are related to members of the genus Desulfovibrio but possess several common antigenic components not present in the other strains tested. The deoxyribonucleic acid of both strains has a buoyant density of 1.724 g/cc and a guanine plus cytosine content of 60.2%. Cell-free extracts of both organisms show absorption bands of cytochrome c 3 and desulfoviridin, characteristic for Desulfovibrio . The two organisms carry out the sulfate-linked lactate fermentation and neither will grow in the absence of sulfate. Both strains contain the enzymes of the dissimilatory pathway of sulfate reduction. Therefore, these studies have demonstrated that the Benghazi and Walvis Bay strains should be regarded as taxonomically distinct from other species of Desulfovibrio .