Deferrisoma camini gen. nov., sp. nov., a moderately thermophilic, dissimilatory iron(III)-reducing bacterium from a deep-sea hydrothermal vent that forms a distinct phylogenetic branch in the Deltaproteobacteria

Abstract

A moderately thermophilic, anaerobic, dissimilatory iron(III)-reducing bacterium (strain S3R1 T ) was isolated from a deep-sea hydrothermal vent chimney located on the Eastern Lau Spreading Centre in the Pacific Ocean at a depth of about 2150 m. Cells of strain S3R1 T were ovals to short rods with a single polar flagellum, Gram-stain-negative, 0.5-0.6 mm in diameter and 0.8-1.3 mm long, growing singly or in pairs. The temperature range for growth was 36-62 6C, with an optimum at 50 6C. The pH range for growth was 5.5-7.5, with an optimum at pH 6.5. Growth of strain S3R1 T was observed at NaCl concentrations ranging from 1.0 to 5.0 % (w/v), with an optimum at 2.0-2.5 % (w/v). The isolate used acetate, fumarate, malate, maleinate, succinate, propanol, palmitate, stearate, peptone and yeast extract as electron donors for growth and iron(III) reduction. All electron donors were oxidized completely to CO 2 and H 2 O. Iron(III) (in the form of ferrihydrite, ferric citrate or ferric nitrilotriacetate) and elemental sulfur (S 0 ) were the electron acceptors that supported growth. The DNA G+C content was 64.4 mol%. Results of 16S rRNA gene sequence analysis showed that the novel bacterium was related to representatives of the orders Desulfuromonadales and Syntrophobacterales with 84-86 % sequence similarity and formed a distinct phylogenetic branch in the Deltaproteobacteria. On the basis of its physiological properties and results of phylogenetic analyses, it is proposed that the new isolate represents the sole species of a novel genus, Deferrisoma camini gen. nov., sp. nov. The type strain of Deferrisoma camini is S3R1 T (5DSM 24185 T 5VKM B-2672 T ).

Deferrisoma palaeochoriense sp. nov., a thermophilic, iron(III)-reducing bacterium from a shallow-water hydrothermal vent in the Mediterranean Sea

“…Most internal clades in Fig. 2 are consistent with the phylogeny reconstructed by Slobodkina et al (2012b).…”

“…The highest sequence identity (99 %) to strain MAG-PB1 T belonged to an uncultured microorganism reported from alkaline hydrothermal springs of Ambitle Island, Papua New Guinea (Meyer-Dombard & Amend, 2014). Its next closest relative is the cultured micro-organism Deferrisoma camini S3R1 T (97 % sequence identity), isolated from a deep hydrothermal vent system in the Eastern Lau Spreading Center (Slobodkina et al, 2012b). Other members of the larger clade include organisms isolated from heavy-metal-contaminated soil, Yellow Sea sediment and sulfate reducers, as reported previously by Slobodkina et al (2012b).…”

“…While strain MAG-PB1 T and D. camini S3R1 T shared some common major CFAs, they differed in their relative abundances. In D. camini S3R1 T , iso-C 17 : 0 , iso-C 15 : 0 and C 18 : 0 represented 34.0, 19.2 and 8.2 % (Slobodkina et al, 2012b), whereas these represented 9.0, 6.1 and 13.7 % of the major CFAs in strain MAG-PB1 T . The rest of the major CFAs in D. camini S3R1 T were not found in strain MAG-PB1 T (Slobodkina et al, 2012b).…”

“…In D. camini S3R1 T , iso-C 17 : 0 , iso-C 15 : 0 and C 18 : 0 represented 34.0, 19.2 and 8.2 % (Slobodkina et al, 2012b), whereas these represented 9.0, 6.1 and 13.7 % of the major CFAs in strain MAG-PB1 T . The rest of the major CFAs in D. camini S3R1 T were not found in strain MAG-PB1 T (Slobodkina et al, 2012b). The phenotypic characteristics of the new isolate also distinguish it based on its higher optimal growth temperature, overall broader growth ranges, its capacity for chemolithoautotrophy, Mn(IV) reduction and its inability to oxidize acetate or reduce S 0 .…”

“…Within the Bacteria, a variety of Fe(III) reducers have been isolated and described from these globally widespread hydrothermal systems. For example, at deep-sea hydrothermal vents, members of the classes Deltaproteobacteria (Kashefi et al, 2003;Slobodkina et al, 2012b) and Gammaproteobacteria (Gao et al, 2006) of the phylum Proteobacteria, as well as members of the phylum Deferribacteres (species of the genus Deferribacter) have been described (Miroshnichenko et al, 2003;Slobodkina et al, 2009a). In terrestrial hydrothermal vents and springs, members of the phyla Aquificae (Aguiar et al, 2004), Acidobacteria (Losey et al, 2013) and Actinobacteria (Itoh et al, 2011) have been described; however, the majority of the Fe(III)-reducing species in culture belong to the phylum Firmicutes (Slobodkin et al, 1997(Slobodkin et al, , 1999(Slobodkin et al, , 2006Zavarzina et al, 2002;Gorlenko et al, 2004;Sokolova et al, 2004;Haouari et , 2012).…”