Summary auto-generated
This study determined the phylogenetic positions of five Gram-negative, strictly anaerobic bacterial species by analyzing their 16S rRNA gene sequences. Formivibrio citricus and Propionivibrio dicarboxylicus belong to the beta-subclass of Proteobacteria, with Propionivibrio moderately related to Rhodocyclus species. The remaining three species—Anaerobiospirillum thomasii, Succinimonas amylolytica, and Succinivibrio dextrinosolvens—cluster together within the gamma-subclass of Proteobacteria, along with Ruminobacter amylophilus. These four gamma-subclass genera share phenotypic and phylogenetic characteristics, including carbohydrate fermentation producing succinate and acetate, and form a distinct evolutionary lineage separate from other gamma-Proteobacteria families. Based on their phylogenetic coherence and common taxonomic features, the authors propose the new bacterial family Succinivibrionaceae, with Succinivibrio as the type genus. The evolutionary analysis suggests these organisms likely originated in anaerobic, starch-rich environments and subsequently colonized animal gastrointestinal tracts, with ruminants adopting these bacteria approximately 53 million years ago.
Key findings
- Formivibrio citricus and Propionivibrio dicarboxylicus are members of the beta-subclass of Proteobacteria, while Anaerobiospirillum thomasii, Succinimonas amylolytica, and Succinivibrio dextrinosolvens belong to the gamma-subclass
- The three gamma-subclass species plus Ruminobacter amylophilus form a distinct phylogenetic cluster with 16S rRNA similarity values ranging from 87.1-93.6%
- A new bacterial family, Succinivibrionaceae, is proposed to formally classify this phylogenetically coherent gamma-subclass lineage
- These anaerobic carbohydrate-fermenting bacteria likely originated in starch-rich anaerobic environments and subsequently colonized animal gastrointestinal tracts during vertebrate evolution
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Abstract
H Hippe, A Hagelstein, I Kramer, J Swiderski and E Stackebrandt
DSMZ -- Deutsche Sammlung von Mikroorganismen und Zellkulturen GmbH, Mascheroder Weg 1b, D-38124 Braunschweig, Germany
The phylogenetic position of Gram-negative, strictly anaerobic, non-spore-forming bacteria, representing four different genera, was determined by analysis of their 16S rDNA sequences. Formivibrio citricus and Propionivibrio dicarboxylicus are members of the beta-subclass of the class Proteobacteria. While Formivibrio citricus stands phylogenetically isolated, Propionivibrio dicarboxylicus is moderately related to members of the genus Rhodocyclus. Succinimonas amylolytica and Succinivibrio dextrinosolvens are members of the gamma-subclass of the class Proteobacteria in which they, together with members of the genus Anaerobiospirillum and Ruminobacter amylophilus, form a separate line of descent. This phylogenetic group is described as Succinivibrionaceae fam. nov.