Polymerase chain reaction amplification was used to compare different regions of the cytochrome c3 gene from nine strains of Desulfovibrio vulgaris, to examine homology within the species. Six 30-base polymerase chain reaction primers and three probes were synthesized on the basis of the published nucleic acid sequence of the cytochrome c3 gene from D. vulgaris, NCIMB 8303. Amplifications were performed on genomic DNA isolated from NCIMB 8303 as well as eight other strains. Six strains, NCIMB 8302, 8305, 8306, 8311, 11779, and DSM 2119, showed amplification products of equal size and quantity to those of strain 8303. Two other strains, NCIMB 8456 and DSM 1744, either showed reduced levels or no detectable amplification products. These results were confirmed by hybridization of amplified DNA to radiolabeled probes specific for each product. DNA sequencing of a 145-bp polymerase chain reaction fragment from strains NCIMB 8302, 8303, 11779, and DSM 2119 revealed complete sequence homology between these strains, whereas slight differences were seen with strain NCIMB 8456. Amino acid sequencing of the first 20 residues of cytochrome c3 purified from strains NCIMB 8456 and 8303 also showed differences in the two proteins. In contrast to the results obtained with strain NCIMB 8456, limited homology was observed between the first 20 amino acid residues of cytochrome c3 from strain DSM 1744 and strain NCIMB 8303.Key words: cytochrome c3, Desulfovibrio, polymerase chain reaction amplification, taxonomy.
Structural studies on Desulfovibrio gigas cytochrome c3 by two-dimensional 1H-nuclear-magnetic-resonance spectroscopy