Pelosinus defluvii sp. nov., isolated from chlorinated solvent-contaminated groundwater, emended description of the genus Pelosinus and transfer of Sporotalea propionica to Pelosinus propionicus comb. nov. , on the basis of their phenotypic and phylogenetic properties. The isolates were Gram-negative, spore-forming, motile rods with peritrichous flagella. Growth occurred at 10-42 6C and pH 5.5-8.5. Fermentative growth was observed on Casamino acids, fructose, fumarate, glucose, glycerol, pyruvate and yeast extract. The major organic acids produced from glucose and glycerol fermentation were propionate and acetate. The major organic acids produced from fermentation of fumarate were propionate, acetate and succinate. The major cellular fatty acids were summed feature 4 (consisting of C 15 : 1 v8c and/or C 15 : 2 ), summed feature 8 (consisting of C 17 : 1 v8c and/ or C 17 : 2 ) and C 14 : 0 dimethyl aldehyde. The polar lipids comprised aminophospholipids, including phosphatidylethanolamine and phosphatidylserine, and an unknown phospholipid. The genomic DNA G+C content was 39.2 mol%. We propose that strains SHI-1 T and SHI-2 are assigned to a novel species of the genus Pelosinus, with the name Pelosinus defluvii sp. nov. The genus Pelosinus was described by Shelobolina et al. (2007) to accommodate a bacterium belonging to the Sporomusa-Pectinatus-Selenomonas group of the phylum Firmicutes (Strömpl et al., 1999). This group is a heterogeneous assemblage of organisms with Gram-negative cell walls and is also referred to as clostridial cluster IX (Collins et al., 1994) and the family Veillonellaceae (Rogosa, 1971). At present, the genus Pelosinus is represented by a single species, Pelosinus fermentans, the type strain of which was first isolated from a subsurface kaolin deposit in Russia (Shelobolina et al., 2007). The genus Sporotalea contains the single species Sporotalea propionica and was described by Boga et al. (2007) to accommodate a propionigenic bacterium isolated from the intestinal tract of the soilfeeding termite Thoracotermes macrothorax. At the time of initial publication, the closest phylogenetic relative reported for both P. fermentans R7 T (Shelobolina et al., A supplementary figure is available with the online version of this paper.

Three facultatively anaerobic, Gram-positive staining, rod-shaped, non-spore forming, flagellated bacterial strains, BL-75, BL-79(T) and BL-104, were isolated from chlorinated solvent-contaminated groundwater. Phylogenetic analysis based on 16S rRNA gene sequence comparisons showed them to represent a distinct lineage within the genus Actinomyces with sequence identities in the range of <88-95.4% with previously described Actinomyces species. The strains were oxidase and catalase negative. Nitrate was not reduced. Esculin was hydrolyzed. Growth occurred in the temperature range of 20-43°C (optimum 30-37°C) and pH range 4.5-9.0 (optimum pH 6.5). Substrates supporting growth included various mono-, di-, and tri-saccharides. The end products of glucose fermentation were acetate, lactate, succinate and formate. Fermentative growth was observed in the presence of near saturation concentrations of perchloroethene (PCE) and toluene and in the presence of 1,2-dichloroethane and 1,1,2-trichloroethane at concentrations up to at least 24.4 mM and 11.2 mM, respectively. The dominant cellular fatty acids when grown in peptone/yeast extract/glucose (PYG) medium were C(18:1) ω9c, C(16:0), and C(14:0). The peptidoglycan was found to contain the amino acids alanine, glutamic acid, lysine, and ornithine at approximate molar ratios of 1.7 Ala: 2.3 Glu: 1.3 Lys: 1.0 Orn. The cell wall sugars were found to include rhamnose and mannose. The polar lipids were found to include diphosphatidylglycerol (DPG), phosphatidylglycerol (PG), phospholipid (PL), phosphoglycolipids (PGL), and glycolipids (GL). The main respiratory quinone of strain BL-79(T) was MK-9(H(4)), with minor components MK-10(H(4)) and MK-8(H(4)). The DNA mol% G+C content of the type strain is 69.8%. On the basis of phylogenetic and phenotypic characteristics, these strains could be differentiated from previously described species of the genus Actinomyces. Strains BL-75, BL-79(T) and BL-104 are designated as a novel species, for which the name Actinomyces naturae sp. nov. is proposed. This is the first Actinomyces species isolated from an environmental rather than human or animal sources. The type strain of Actinomyces naturae is BL-79(T) (= CCUG 56698(T) = NRRL B-24670(T)).