title: Thermoflexus hugenholtzii gen. nov., sp. nov., a thermophilic, microaerophilic, filamentous bacterium representing a novel class in the Chloroflexi, Thermoflexia classis nov., and description of Thermoflexaceae fam. nov. and Thermoflexales ord. nov.
abstract: A thermophilic, filamentous, heterotrophic bacterium, designated strain JAD2(T), a member of an as-yet uncultivated lineage that is present and sometimes abundant in some hot springs worldwide, was isolated from sediment of Great Boiling Spring in Nevada, USA. Cells had a mean diameter of 0.3 µm and length of 4.0 µm, and formed filaments that typically ranged in length from 20 to 200 µm. Filaments were negative for the Gram stain reaction, spores were not formed and motility was not observed. The optimum temperature for growth was 72.5-75 °C, with a range of 67.5-75 °C, and the optimum pH for growth was 6.75, with a range of pH 6.5-7.75. Peptone, tryptone or yeast extract were able to support growth when supplemented with vitamins, but no growth was observed using a variety of defined organic substrates. Strain JAD2(T) was microaerophilic and facultatively anaerobic, with optimal growth at 1% (v/v) O2 and an upper limit of 8% O2. The major cellular fatty acids (>5%) were C(16 : 0), C(19 : 0), C(18 : 0), C(20 : 0) and C(19 : 1). The genomic DNA G+C content was 69.3 mol%. Phylogenetic and phylogenomic analyses using sequences of the 16S rRNA gene and other conserved genes placed JAD2(T) within the phylum Chloroflexi, but not within any existing class in this phylum. These results indicate that strain JAD2(T) is the first cultivated representative of a novel lineage within the phylum Chloroflexi, for which we propose the name Thermoflexus hugenholtzii gen. nov., sp. nov., within Thermoflexia classis nov., Thermoflexales ord. nov. and Thermoflexaceae fam. nov. The type strain of Thermoflexus hugenholtzii is JAD2(T) ( = JCM 19131(T) = CCTCC AB-2014030(T)).
authors.affiliation: School of Life Sciences, University of Nevada, Las Vegas, NV 89154, USA.
authors.forename: Jeremy A
authors.initials: JA
authors.lastname: Dodsworth
authors.affiliation: School of Life Sciences, University of Nevada, Las Vegas, NV 89154, USA.
authors.forename: Jonathan
authors.initials: J
authors.lastname: Gevorkian
authors.affiliation: School of Life Sciences, University of Nevada, Las Vegas, NV 89154, USA.
authors.forename: Fairuz
authors.initials: F
authors.lastname: Despujos
authors.affiliation: School of Life Sciences, University of Nevada, Las Vegas, NV 89154, USA.
authors.forename: Jessica K
authors.initials: JK
authors.lastname: Cole
authors.affiliation: School of Life Sciences, University of Nevada, Las Vegas, NV 89154, USA.
authors.forename: Senthil K
authors.initials: SK
authors.lastname: Murugapiran
authors.affiliation: Key Laboratory of Microbial Diversity in Southwest China, Ministry of Education, Yunnan Institute of Microbiology, Yunnan University, Kunming 650091, PR China.|Department of Life Sciences and Technology, Xinxiang Medical University, Xinxiang 453003, PR China.
authors.forename: Hong
authors.initials: H
authors.lastname: Ming
authors.affiliation: Key Laboratory of Biogeography and Bioresource in Arid Land, CAS, Xinjiang Institute of Ecology and Geography, Chinese Academy of Sciences, Ürümqi 830011, PR China.|Key Laboratory of Microbial Diversity in Southwest China, Ministry of Education, Yunnan Institute of Microbiology, Yunnan University, Kunming 650091, PR China.
authors.forename: Wen-Jun
authors.initials: WJ
authors.lastname: Li
authors.affiliation: Laboratory of Alpine Ecology and Biodiversity, Institute of Tibetan Plateau Research, Chinese Academy of Sciences, Beijing 10085, PR China.
authors.forename: Gengxin
authors.initials: G
authors.lastname: Zhang
authors.affiliation: Environmental Molecular Sciences Laboratory, Pacific Northwest National Laboratory, PO Box 999, Mail Stop K8-93, Richland, WA 99352, USA.
authors.forename: Alice
authors.initials: A
authors.lastname: Dohnalkova
authors.affiliation: School of Life Sciences, University of Nevada, Las Vegas, NV 89154, USA.
authors.forename: Brian P
authors.initials: BP
authors.lastname: Hedlund
mesh_terms: D015373:Bacterial Typing Techniques; D001482:Base Composition; D041862:Chloroflexi / Q000145:classification* / Q000235:genetics / Q000302:isolation & purification; D004269:DNA, Bacterial / Q000235:genetics; D005227:Fatty Acids / Q000737:chemistry; D019015:Geologic Sediments / Q000382:microbiology; D045482:Hot Springs / Q000382:microbiology*; D006358:Hot Temperature; D008969:Molecular Sequence Data; D009505:Nevada; D010802:Phylogeny; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D017422:Sequence Analysis, DNA
chemical_list: D004269:DNA, Bacterial; D005227:Fatty Acids; D012336:RNA, Ribosomal, 16S