Summary auto-generated
This study proposes reclassifying Desulfomonas pigra, the only species in its genus, as Desulfovibrio piger based on molecular and phenotypic analysis. Researchers compared Desulfomonas pigra with Desulfovibrio desulfuricans and 'Desulfovibrio fairfieldensis' strains using growth characteristics, DNA G-C content, 16S rDNA sequences, and internal transcribed spacer (ITS) analysis. Although Desulfomonas pigra differs phenotypically from Desulfovibrio species in cell shape (straight non-motile rods versus curved motile rods), molecular evidence strongly supports reclassification. The 16S rDNA phylogenetic analysis showed Desulfomonas pigra shares 95-96% sequence similarity with Desulfovibrio species. DNA G-C content ranged from 59-64 mol%, within the accepted genus variation threshold. Both organisms share key biochemical features including desulfoviridin and cytochrome c, and both are obligate anaerobic sulfate-reducing bacteria that oxidize organic compounds incompletely to acetate. Based on previous suggestions and these findings, the authors formally propose transferring Desulfomonas pigra to the genus Desulfovibrio as Desulfovibrio piger comb. nov., requiring emendation of the genus description to include both curved and straight rod morphologies and motile or non-motile cells.
Key findings
- Desulfomonas pigra shows 95-96% 16S rDNA sequence similarity to Desulfovibrio species, clustering within the Desulfovibrio phylogenetic group
- DNA G-C content of 59-64 mol% across tested strains falls within the accepted range for a single genus
- Desulfomonas pigra and Desulfovibrio species share diagnostic biochemical features including desulfoviridin, cytochrome c, and identical metabolic patterns despite morphological differences
- Desulfomonas pigra was found as the most prevalent sulfate-reducing bacterium in feces of inflammatory bowel disease patients, increasing clinical relevance
- Genus Desulfovibrio definition was emended to include both curved and straight, motile and non-motile rod morphologies to accommodate the reclassification
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Abstract
J. Loubinoux, FMA. Valente, IAC. Pereira, A. Costa, PAD. Grimont and A. E. Le Faou
Laboratoire de Microbiologie UMR CNRS 7565, Hopital de Brabois-Adultes, CHU de Nancy, 54511 Vandoeuvre-les-Nancy Cedex, France
The growth characteristics, DNA G+C content and sequences of 16S rDNA and the transcribed 16S--23S rDNA internal spacer were determined for Desulfomonas pigra ATCC 29098(T), Desulfovibrio desulfuricans subsp. desulfuricans strains Essex 6(T) (=ATCC 29577(T)) and MB (=ATCC 27774) and 'Desulfovibrio fairfieldensis' ATCC 700045. Despite phenotypic differences (shape and motility) between Desulfomonas pigra and Desulfovibrio strains, the molecular analysis suggests that Desulfomonas pigra should be reclassified within the genus Desulfovibrio. Thus, the reclassification is proposed of Desulfomonas pigra, the type and only species of the genus, as Desulfovibrio piger comb. nov., which implies the emendation of the description of the genus Desulfovibrio.