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A thermotolerant, Gram-stain-positive, aerobic, sporangium-forming actinomycete, strain RA45T, was isolated from a desert region in Xinjiang Uigur Autonomous Region, north-western China. Comparative analysis of the 16S rRNA gene sequence and phenotypic characterization revealed that strain RA45Tbelonged phylogenetically to the familyPseudonocardiaceaeof the suborderPseudonocardineae. Strain RA45Tshowed more than 5 % 16S rRNA gene sequence divergence from recognized species of genera in the familyPseudonocardiaceae, forming a distinct lineage within the evolutionary radiation occupied by the generaAmycolatopsis,Prauserella,Thermocrispum,Saccharomonospora,SaccharopolysporaandSciscionella, but distinct from each of them. The affiliation to the family was supported by the presence of suborder- and family-specific 16S rRNA signature nucleotides, a DNA G+C content of 69.9 mol%, the presence ofmeso-diaminopimelic acid, ribose, arabinose, glucose and galactose, which are characteristic components of cell-wall chemotype IV of actinomycetes, the presence of menaquinone MK-9(H4) as the major respiratory lipoquinone, a lack of mycolic acids and the presence of anN-acetylated type of muramic acid. However, strain RA45Tdiffered from known genera of the family in its polar lipid composition: the major phospholipids were phosphatidylethanolamine, phosphatidylinositol mannosides, phosphatidylmethylethanolamine, diphosphatidylglycerol, phospholipids of unknown structure and phospholipids of unknown structure containing glucosamine (phospholipid type IV). Based on its morphological, chemotaxonomic and phylogenetic characteristics, strain RA45Tis considered to represent a novel species of a new genus in the familyPseudonocardiaceae, for which the nameYuhushiella desertigen. nov., sp. nov. is proposed. The type strain ofYuhushiella desertiis RA45T(=CGMCC 4.5579T=JCM 16584T).

A novel strictly anaerobic, moderately halophilic and mesophilic bacterium, designated strain SOL3f37T, was isolated from a hydrocarbon-polluted soil surrounding a deep petroleum environment located in south Tunisia. Cells of strain SOL3f37T stained Gram-positive and were motile, straight and spore-forming. Strain SOL3f37T had a typical Gram-positive-type cell-wall structure, unlike the thick, multilayered cell wall of its closest relative Clostridiisalibacter paucivorans. The major fatty acids were iso-C15 : 0 (41 %), iso-C14 : 0 3-OH and/or iso-C15 : 0 dimethyl acetal (21.6 %), iso-C13 : 0 (4.4 %), anteiso-C15 : 0 (3.9 %) and iso-C15 : 1 (2.8 %). Strain SOL3f37T grew between 20 and 48 °C (optimum 40 °C) and at pH 6.2–8.1 (optimum pH 6.9). Strain SOL3f37T required at least 0.5 g NaCl l−1 and grew in the presence of NaCl concentrations up to 150 g l−1 (optimum 40 g l−1). Yeast extract (2 g l−1) was required for degradation of pyruvate, fumarate, fructose, glucose and mannitol. Also, strain SOL3f37T grew heterotrophically on yeast extract, peptone and bio-Trypticase, but was unable to grow on Casamino acids. Sulfate, thiosulfate, sulfite, elemental sulfur, fumarate, nitrate and nitrite were not reduced. The DNA G+C content was 30.7 mol%. Phylogenetic analysis based on 16S rRNA gene sequences revealed that strain SOL3f37T was a member of the family Clostridiaceae in the order Clostridiales; strain SOL3f37T was related to members of various genera of the family Clostridiaceae. It exhibited highest 16S rRNA gene sequence similarity (93.4 %) with Clostridiisalibacter paucivorans 37HS60T, 91.8 % with Thermohalobacter berrensis CTT3T and 91.7 % with Caloranaerobacter azorensis MV1087T. On the basis of genotypic, phenotypic and phylogenetic data, it is suggested that strain SOL3f37T represents a novel species in a new genus. The name Sporosalibacterium faouarense gen. nov., sp. nov. is proposed, with SOL3f37T (=DSM 21485T =JCM 15487T) as the type strain of Sporosalibacterium faouarense.

A novel aerobic, heterotrophic bacterium, designated BiosLi39T, was isolated from the South East Pacific Ocean. Cells were Gram-negative gliding rods forming yellow colonies on marine agar. The isolate was oxidase-, catalase- and alkaline phosphatase-positive andβ-galactosidase-negative. Strain BiosLi39Tgrew at 20-37 °C (optimum 30 °C), at pH 7.0–9.0 (optimum pH 8.0) and with 20–60 g NaCl l−1(optimum 30–50 g NaCl l−1). The fatty acids (>1 %) comprised iso-C14 : 0, iso-C15 : 1G, iso-C15 : 0, anteiso-C15 : 0, C15 : 1G, C15 : 0, iso-C15 : 02-OH, iso-C16 : 1G, iso-C16 : 0, iso-C16 : 03-OH, iso-C16 : 02-OH, iso-C17 : 03-OH, C17 : 02-OH and three unidentified components with equivalent chain lengths of 17.87, 18.10 and 18.71. A significant proportion of the hydroxylated fatty acids are amide-linked. The lipid pattern indicated the presence of phosphatidylethanolamine, two unidentified aminolipids and three unidentified polar lipids. The strain contained menaquinone 7 as the sole respiratory lipoquinone and did not produce flexirubin-type pigments. The G+C content of the genomic DNA was 37.2 mol%. Comparative 16S rRNA gene sequence analysis indicated that strain BiosLi39Twas distantly related to all of the representatives of the phylumBacteroidetes. Its closest relative wasMarinoscillum furvescensIFO 15994T, with which it shared 92.5 % 16S rRNA gene sequence similarity. On the basis of genotypic, phenotypic and chemotaxonomic characteristics, we propose a novel genus and species,Ekhidnagen. nov., sp. nov., with type strain BiosLi39T(=DSM 19307T=CIP 109600T=OOB 398T).

Abstract Marine pelagic redoxclines are areas of enhanced biogeochemical cycling inhabited by distinct functional groups of prokaryotes. In this study, the diversity and abundance of archaeal and bacterial nitrifying populations throughout a pelagic redoxcline in the central Baltic Sea were examined using a suite of molecular methods. 16S rRNA/rRNA gene as well as bacterial and archaeal amoA mRNA/amoA gene fingerprints and clone libraries revealed that the putative nitrifying assemblages consisted solely of one crenarchaeotal subcluster, named GD2, which was closely related to Candidatus Nitrosopumilus maritimus. Neither distinct differences between transcript- and gene-based fingerprints nor pronounced differences in the crenarchaeotal composition throughout the whole redoxcline were detected. The abundance of this GD2 subgroup, as determined by the oligonucleotide probe Cren537 and the newly developed and more specific probe Cren679 showed that GD2 and total crenarchaeotal cell numbers were nearly identical throughout the redoxcline. The highest GD2 abundance (2.3 × 105 cells ml−1) occurred in the suboxic zone, accounting for around 26% of total prokaryotic cells. Below the chemocline, GD2 abundance was relatively stable (1.5–1.9 × 105 cells ml−1). Archaeal amoA expression was detected only in the putative nitrification zone and formed a narrow band in the suboxic layer, where ammonium, oxygen, nitrate, nitrite and phosphate concentrations were below 5 μmol l−1. To our knowledge this is the first study to show the dominance of only one crenarchaeotal nitrifying key cluster in a natural habitat. The metabolic properties and survival mechanisms present in this cluster inside and outside the nitrification zone remain to be determined.

Two novel thermophilic and slightly acidophilic strains, Kam940Tand Kam1507b, which shared 99 % 16S rRNA gene sequence identity, were isolated from terrestrial hot springs of the Uzon caldera on the Kamchatka peninsula. Cells of both strains were non-motile, regular cocci. Growth was observed between 55 and 85 °C, with an optimum at 65–70 °C (doubling time, 6.1 h), and at pH 4.5–7.5, with optimum growth at pH 5.5–6.0. The isolates were strictly anaerobic organotrophs and grew on a narrow spectrum of energy-rich substrates, such as beef extract, gelatin, peptone, pyruvate, sucrose and yeast extract, with yields above 107cells ml−1. Sulfate, sulfite, thiosulfate and nitrate added as potential electron acceptors did not stimulate growth when tested with peptone. H2at 100 % in the gas phase inhibited growth on peptone. Glycerol dibiphytanyl glycerol tetraethers (GDGTs) with zero to four cyclopentyl rings were present in the lipid fraction of isolate Kam940T. The G+C content of the genomic DNA of strain Kam940Twas 37 mol%. Phylogenetic analysis based on 16S rRNA gene sequences indicated that the isolates were archaea of the phylumCrenarchaeota, only distantly related to the cultured members of the classThermoprotei(no more than 89 % identity), and formed an independent lineage adjacent to the ordersDesulfurococcalesandAcidilobalesand clustering only with uncultured clones from hot springs of Yellowstone National Park and Iceland as the closest relatives. On the basis of their phylogenetic position and novel phenotypic features, isolates Kam940Tand Kam1507b are proposed to be assigned to a new genus and species,Fervidicoccus fontisgen. nov., sp. nov. The type strain ofFervidicoccus fontisis strain Kam940T(=DSM 19380T=VKM B-2539T). The phylogenetic data as well as phenotypic properties suggest that the novel crenarchaeotes form the basis of a new family,Fervidicoccaceaefam. nov., and order,Fervidicoccalesord. nov., within the classThermoprotei.

AbstractIntracellular inclusions containing chlamydia‐like organisms are frequently observed in the gill epithelial cells of Atlantic salmon, Salmo salar L., cultured in fresh water in Ireland. In this study, the causative agent was identified in four separate freshwater sites, using 16s rRNA sequencing, as ‘Candidatus Clavochlamydia salmonicola’. Histopathology and real‐time (RT) PCR were used to further assess infections. The prevalence of infection ranged from 75–100% between sites and infection intensity was highly variable. No significant lesions were associated with these infections. As a diagnostic tool, RT‐PCR proved marginally more sensitive than histopathology. The fate of ‘Candidatus Clavochlamydia salmonicola’ in Atlantic salmon post‐seawater transfer was investigated in a 12‐week marine longitudinal study. Both RT‐PCR and histopathological examination indicate that the organism disappears from the gills 4–6 weeks post‐transfer.

A moderately thermophilic chemoheterotrophic bacterium, strain Mat9-16T, was isolated from microbial mats developed in hot spring water streams from Yumata, Nagano, Japan. Cells of strain Mat9-16Twere strictly anaerobic, Gram-stain-negative, non-sporulating, non-motile and short to long rods (2.0–15.5 μm in length). Strain Mat9-16Tgrew fermentatively with optimum growth at 45 °C, pH 7.0–7.5 and 1 % NaCl (w/v). Phylogenetic analysis based on the 16S rRNA gene revealed that strain Mat9-16Twas affiliated with an uncultivated lineage, and the nearest cultivated neighbours were green sulfur bacteria belonging to the classChlorobeawith 77–83 % sequence similarity. However, strain Mat9-16Tcould not grow phototrophically and did not possess light-harvesting structures, morphologically and genetically, such as the chlorosomes of green sulfur bacteria. On the basis of phenotypic features and phylogenetic position, a novel genus and species are proposed for strain Mat9-16T, to be namedIgnavibacterium albumgen. nov., sp. nov. (=NBRC 101810T=DSM 19864T). We also propose to place the cultivated bacterial lineage accommodating the sole representative Mat9-16Tin a novel class,Ignavibacteriaclassis nov. In addition, we present a formal description of the phylum-level taxon‘Chlorobi’asChlorobiphyl. nov.

A Gram-negative, aerobic, rod-shaped bacterium, designated strain CL-33T, was isolated from the encrusting pore coral Montipora aequituberculata collected from seawater off the coast of southern Taiwan. 16S rRNA gene sequence analysis showed that the strain clustered closely with Endozoicomonas elysicola MKT110T (96.7 % similarity). The novel strain required NaCl for growth and exhibited optimal growth at 25 °C and in the presence of 2–3 % NaCl. Predominant cellular fatty acids were summed feature 3 (C16 : 1 ω7c and/or C16 : 1 ω6c; 39.6 %), summed feature 8 (C18 : 1 ω7c and/or C18 : 1 ω6c; 32.8 %) and C16 : 0 (12.0 %). The DNA G+C content of strain CL-33T was 50.0 mol%. The results of physiological and biochemical tests allowed the clear phenotypic differentiation of this isolate from E. elysicola. It is evident from the genotypic, phenotypic and chemotaxonomic data presented that strain CL-33T represents a novel species of the genus Endozoicomonas, for which the name Endozoicomonas montiporae sp. nov. is proposed. The type strain is CL-33T (=LMG 24815T =BCRC 17933T).

A novel halophilic actinomycete, designated strain YIM 93223T, was isolated from a salt lake in Xinjiang Province, north-west China, and was subjected to a polyphasic taxonomic study. The isolate grew at 25–45 °C, at pH 6–8 and in the presence of 1–15 % (w/v) NaCl; no growth was observed in the absence of NaCl. Strain YIM 93223T contained meso-diaminopimelic acid, glutamic acid and alanine as cell-wall amino acids, and glucose and galactose as major whole-cell-wall sugars. Major fatty acids were iso-C16 : 0, C16 : 0 and C16 : 1 ω7c/iso-C15 : 0 2-OH. MK-8(H4) was the predominant menaquinone. The genomic DNA G+C content was 66.1 mol%. Phylogenetic analysis based on 16S rRNA gene sequences showed that strain YIM 93223T belongs to the genus Amycolatopsis. It shared highest 16S rRNA gene sequence similarity with Amycolatopsis palatopharyngis 1BDZT (96.6 %) and Amycolatopsis marina Ms392AT (96.4 %), but lower values (94.5–96.2 %) with the type strains of other recognized species of the genus Amycolatopsis. On the basis of the data from this polyphasic study, strain YIM 93223T is considered to represent a novel species of the genus Amycolatopsis, for which the name Amycolatopsis halophila sp. nov. is proposed. The type strain is YIM 93223T (=DSM 45216T =KCTC 19403T).

An obligate anaerobic, Gram-staining-negative, mesophilic, cellulolytic bacterium, strain H1T, was isolated from the rumen content of yak. Cells were straight to slightly curved rods, 0.8–1.0×3.0–4.0 μm in size, non-motile and encapsulated with mucous materials. Elliptical and terminal spores that swelled the cells were produced occasionally. The strain grew at 25–45 °C (optimum, 38 °C) and pH 6.0–7.8 (optimum, pH 6.7). Cellulose, cellobiose, xylan, xylose and maltose were used as carbon and energy sources, but not glucose. Products from cellulose and cellobiose fermentation were formic acid, acetic acid, carbon dioxide and trace amounts of ethanol, lactic acid and succinic acid. The genomic DNA G+C content was 33.7±1.2 mol%. The predominant fatty acids were C16 : 0(27.1 %), C14 : 0(9.2 %) and iso-C16 : 0(6.4%). Based on the 16S rRNA gene sequence analysis, strain H1Twas affiliated to the clostridial rRNA cluster XIVb and showed the highest 16S rRNA gene sequence similarity toClostridium lentocellumDSM 5427T(96.0 %). These two strains formed a distinct lineage of the family ‘Lachnospiraceae’. Based on data from this polyphasic taxonomic study, a new genus,Cellulosilyticumgen. nov., is proposed.Cellulosilyticum ruminicolasp. nov. is proposed for strain H1T. The type strain ofCellulosilyticum ruminicolasp. nov. is strain H1T(=CGMCC 1.5065T=JCM 14822T).Clostridium lentocellumwas reclassified in the new genus asCellulosilyticum lentocellumcomb. nov. (type strain RHM5T=ATCC 49066T=DSM 5427T=NCIMB 11756T).