Ardenticatena maritima gen. nov., sp. nov., a ferric iron- and nitrate-reducing bacterium of the phylum ‘ Chloroflexi ’ isolated from an iron-rich coastal hydrothermal field, and description of Ardenticatenia classis nov.

Abstract

A novel thermophilic, chemoheterotrophic, Gram-negative-staining, multicellular filamentous bacterium, designated strain 110ST, was isolated from an iron-rich coastal hydrothermal field in Japan. The isolate is facultatively aerobic and chemoheterotrophic. Phylogenetic analysis using 16S rRNA gene sequences nested strain 110ST in a novel class-level clone cluster of the phylum ‘ Chloroflexi ’. The isolate grows by dissimilatory iron- and nitrate-reduction under anaerobic conditions, which is the first report of these abilities in the phylum ‘ Chloroflexi ’. The organism is capable of growth with oxygen, ferric iron and nitrate as a possible electron acceptor, has a wide range of growth temperatures, and tolerates higher NaCl concentrations for growth compared to the other isolates in the phylum. Using phenotypic and phylogenetic data, strain 110ST ( = JCM 17282T = NBRC 107679T = DSM 23922T = KCTC 23289T = ATCC BAA-2145T) is proposed as the type strain of a novel species in a new genus, Ardenticatena maritima gen. nov., sp. nov. In addition, as strain 110ST apparently constitutes a new class of the phylum ‘ Chloroflexi ’ with other related uncultivated clone sequences, we propose Ardenticatenia classis nov. and the subordinate taxa Ardenticatenales ord. nov. and Ardenticatenaceae fam. nov.

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

“…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). In shallow-water hydrothermal vent environments, the only Fe(III)-reducing bacterium described to date is Ardenticatena maritima, belonging to the phylum Chloroflexi (Kawaichi et al, 2013). Documented chemical and microbiological evidence from hydrothermal vent systems shows a variety of yet unknown bacterial lineages with potential links to Fe(III) reduction (Sievert et al, 1999;Slobodkin et al, 2001;Slobodkin, 2005;Hirayama et al, 2007;Meyer-Dombard & Amend, 2014).…”

Genomic and in situ investigations of the novel uncultured Chloroflexi associated with 0092 morphotype filamentous bulking in activated sludge

“…The genome bin is enclosed by the polygon. described and characterized isolate (Kawaichi et al, 2013), although our analyses supports its possible inclusion into the class Anaerolineae (see Figure 3 and Supplementary Figure S2). The current composition of Chloroflexi classes is based on 16 S rRNA gene sequence phylogeny and includes few isolates and genomes (see Figure 3 and Supplementary Figure S2).…”

“…However, the ability of these isolates to utilize nitrite as an electron acceptor to support anaerobic growth is yet to be assessed (Sekiguchi et al, 2003). The related Ardenticatena maritima genome reveals the potential for reduction of nitrate to either dinitrogen gas or ammonia (Kawaichi et al, 2015), although only the latter product was detected in pure culture studies (Kawaichi et al, 2013).…”

Bacterial and Archaeal Diversity in an Iron-Rich Coastal Hydrothermal Field in Yamagawa, Kagoshima, Japan

“…Despite the presence of iron-bearing rocks, no well-known bacterial iron reducers, such as the members of the genera Geobacter and Shewanella , were detected in this study. In fact, the isolation of an iron reducer affiliated to the phylum Chloroflexi , which is the first report of this ability in the phylum, was achieved using sandy sediment from this environment (26). Since the ability to grow by dissimilatory Fe(III) reduction is species or even strain specific, further studies, especially based on culture-dependent approaches, are necessary to reveal the effect of the high amount of iron in this environment on the bacterial (and also archaeal) community.…”

“…Recently, two novel thermophilic bacteria were isolated from this environment (26, 61). In addition, strains of strictly aerobic, neutrophilic, hyperthermophilic archaeal genus Aeropyrum (Tanaka et al unpublished data) and two novel strains of virus infecting the type species of the genus Aeropyrum were successfully isolated (38, 39).…”