- Volume 52, Issue 4, 2002
Volume 52, Issue 4, 2002
- Articles
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Methanobrevibacter acididurans sp. nov., a novel methanogen from a sour anaerobic digester.
More LessA novel acid-tolerant, hydrogenotrophic methanogen, isolate ATMT, was obtained from an enrichment performed at pH 5.0 using slurry from an acidogenic digester running on alcohol distillery waste. The original pH of the slurry was 5.7 and the volatile fatty acid concentration was 9000 p.p.m. Cells of isolate ATMT were Gram-positive, non-motile and 0.3-0.5 microm in size. They did not form spores. The isolate could grow in the pH range 5.0-7.5, with maximum growth at pH 6.0. The optimum temperature for growth was 35 degrees C. Formate, acetate, methanol, trimethylamine, 2-propanol and 2-butanol were not utilized as growth substrates. Rumen fluid and acetate were required for growth on H2/CO2. Coenzyme M and 2-methylbutyric acid were not required in the presence of rumen fluid. 16S rDNA sequence analysis confirmed the signature sequence of the genus Methanobrevibacter. Morphological and biochemical characteristics of the isolate, together with the 16S rDNA sequence analysis, clearly revealed that the isolate could not be accommodated within any of the existing species of the genus Methanobrevibacter. Therefore, it is proposed that a novel species of the genus Methanobrevibacter should be created for this isolate, Methanobrevibacter acididurans sp. nov., and the type strain is
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Methanothermococcus okinawensis sp. nov., a thermophilic, methane-producing archaeon isolated from a Western Pacific deep-sea hydrothermal vent system.
More LessA novel thermophilic, methane-producing archaeon was isolated from a deep-sea hydrothermal vent chimney at the Iheya Ridge, in the Okinawa Trough, Japan. The cells were highly motile, irregular cocci, with a polar bundle of flagella. Growth was observed between 40 and 75 degrees C (optimum 60-65 degrees C; 30 min doubling time) and between pH 4.5 and 8.5 (optimum pH 6.7). The isolate was a strictly anaerobic autotroph capable of using hydrogen and carbon dioxide as sole sources of energy and carbon. Formate can serve as an alternative energy source. The G+C content of the genomic DNA was 33.5 mol%. Phylogenetic analysis based on 16S rDNA sequences and DNA-DNA hybridization analysis indicated that the isolate was closely related to members of the genera Methanococcus and Methanothermococcus. This isolate, however, could be differentiated from the previously described species of these genera on the basis of its physiological and molecular properties. The name Methanothermococcus okinawensis sp. nov is proposed, with the type strain IH1T (=JCM 11175T=DSM 14208T).
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Vulcanisaeta distributa gen. nov., sp. nov., and Vulcanisaeta souniana sp. nov., novel hyperthermophilic, rod-shaped crenarchaeotes isolated from hot springs in Japan.
More LessSeventeen strains of rod-shaped, heterotrophic, anaerobic, hyperthermophilic crenarchaeotes were isolated from several hot spring areas in eastern Japan, and eight representative strains were characterized further. Cells of these strains were straight to slightly curved rods, 0.4-0.6 microm in width. Occasionally, cells were branched or bore spherical bodies at the poles. They grew optimally at 85-90 degrees C and at pH 4.0-4.5. They utilized yeast extract, peptone, beef extract, Casamino acids, gelatin, starch, maltose and malate as carbon sources and sulfur and thiosulfate as possible electron acceptors. The DNA G+C contents of the novel isolates were 43.9-46.2 mol%. The lipids were mainly cyclic and acyclic tetraether core lipids. Phylogenetic analysis of the 16S rDNA sequences revealed that they represented an independent lineage in the family Thermoproteaceae. Moreover, comparison of the 16S rDNA sequences and a DNA-DNA hybridization study showed that they comprised two species, which could also be differentiated by the maximal growth temperature and degrees of NaCl tolerance. Therefore, a new genus, Vulcanisaeta gen. nov., in the family Thermoproteaceae is proposed to accommodate two novel species, Vulcanisaeta distributa sp. nov. and Vulcanisaeta souniana sp. nov. The type species is V. distributa and the type strains are V. distributa IC 017T (= JCM 11212T = DSM 14429T) and V. souniana IC-059T (= JCM 11219T = DSM 14430T).
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Re-evaluation of the status of the genus Oerskovia, reclassification of Promicromonospora enterophila (Jáger et al. 1983) as Oerskovia enterophila comb. nov. and description of Oerskovia jenensis sp. nov. and Oerskovia paurometabola sp. nov.
Phylogenetic analysis of Promicromonospora enterophila indicates that this taxon clusters with Cellulomonas species, adjacent to Cellulomonas turbata (basonym Oerskovia turbata). 16S rDNA analysis, DNA-DNA reassociation, riboprinting, peptidoglycan analysis and determination of phenotypic properties of various strains of P. enterophila and C turbata reveal that they form a cluster that can be distinguished unambiguously from other Cellulomonas species by morphology, amino acid composition of the cell wall and 16S rDNA signatures. As a result of thispolyphasic study, it appears taxonomically reasonable to re-establish the genus Oerskovia for C turbata and to reclassify P. enterophila as Oerskovia enterophila comb. nov.; two novel species, Oerskovia jenensis sp. nov. (type strain DSM 46000T = CIP 100330T) and Oerskovia paurometabola sp. nov. (type strain DSM 14281T = LMG 20385T), are also proposed.
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Emended description of the genus Trichococcus, description of Trichococcus collinsii sp. nov., and reclassification of Lactosphaera pasteurii as Trichococcus pasteurii comb. nov. and of Ruminococcus palustris as Trichococcus palustris comb. nov. in the low-G+C gram-positive bacteria.
Analyses of 165 rRNA gene sequences, restriction endonuclease digestion fingerprints of 16S-23S intergenic regions, DNA base compositions, fatty-acid profiles, cell-wall chemistry, cell physiology and fermentation end-product composition, along with other biochemical and phenotypic properties, supported the view that Trichococcus flocculiformis EchtT (DSM 2094T), Lactosphaera pasteurii KoTa2T (DSM 2381T), Ruminococcus palustris Z-7189T (DSM 9172T) and an isolate named 'Carnococcus allantoicus' NDP were all very similar and should be merged into a single genus. Detailed characterization of strains Ben 77, Ben 200 and Ben 201 described previously as 'Nostocoida limicola' I, a filamentous bacterium which causes bulking in activated sludge systems, revealed that these strains also belonged to the same genus as T. flocculiformis EchtT, L. pasteurii KoTa2T, R. palustris Z-7189T and 'C allantoicus' NDP. In fact, their shared properties suggested that these strains all belonged to a single species. However, DNA-DNA hybridization data indicated that T. flocculiformis EchtT, all of the 'N. limicola' I isolates and 'C allantoicus' NDP belonged to the same species, whereas L. pasteurii KoTa2T, R. palustris Z-7189T and two new isolates, 37AN3*T and 45AN2, represented three distinct species within the same genus. The priority of the genus name Trichococcus is established and since its validation predates the description of the genus Lactosphaera this name should take precedence. Under certain culture conditions, all of the strains mentioned above could produce chains of cocci. Furthermore, the morphology of T. flocculiformis EchtT could change to a non-filamentous form on certain media. This study proposes that the above strains be reclassified as members of the genus Trichococcus as four species, namely Trichococcus flocculiformis emend. (type strain EchtT = DSM 2094T), Trichococcus pasteurii comb. nov. (type strain KoTa2T = DSM 2381T = ATCC 35945T), Trichococcus collinsii sp. nov. (type strain 37AN3*T = DSM 14526T = ATCC BAA-296T, and Trichococcus palustris comb. nov. (type strain Z-7189T = DSM 9172T).
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Corynebacterium efficiens sp. nov., a glutamic-acid-producing species from soil and vegetables.
Three glutamic-acid-producing coryneform strains were isolated from soil and vegetable samples. Chemotaxonomic investigations indicated that these strains belonged to the genus Corynebacterium. Phylogenetic studies, based on 16S rDNA analysis, demonstrated that the three strains formed a distinct cluster within the genus Corynebacterium and that their nearest relatives were Corynebacterium glutamicum and Corynebacterium callunae, also known as glutamic-acid-producing species. The data from 16S rDNA sequence and DNA-DNA relatedness studies clearly indicated that the three isolates represented a new species within the genus Corynebacterium. All of the isolates could grow at 45 degrees C and produced acid from dextrin; these were the most significant characteristics differentiating the three isolates from their neighbours. On the basis of the data presented here, it is proposed that the three glutamic-acid-producing isolates together be classified as Corynebacterium efficiens sp. nov., the type strain of which is YS-314T (= AJ 12310T = JCM 11189T = DSM 44549T).
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Gordonia westfalica sp. nov., a novel rubber-degrading actinomycete.
A cis-1,4-polyisoprene-degrading bacterium (strain Kb2T) was isolated from foul water taken from the inside of a deteriorated automobile tyre found on a farmer's field in Westfalia, Germany. The strain was aerobic, Gram-positive, exhibited orange smooth and rough colonies on complex nutrient agar, produced elementary branching hyphae that fragmented into rod/coccus-like elements and showed chemotaxonomic markers which were consistent with its classification within the genus Gordonia, i.e. the presence of mesodiaminopimelic acid, arabinose and galactose in whole-cell hydrolysates (cell-wall chemotype IV), N-glycolylmuramic acid in the peptidoglycan wall, a fatty-acid pattern composed of unbranched saturated and monounsaturated fatty acids plus tuberculostearic acid, mycolic acids comprising 56-60 carbon atoms and MK-9(H2) as the only menaquinone. The 16S rDNA sequence of strain Kb2T was found to be most similar to the 16S rDNA sequences of the type strains of Gordonia alkanivorans (DSM 44369T) and Gordonia nitida (KCTC 0605BPT). However, DNA-DNA relatedness data showed that strain Kb2T ( =DSM 44215T NRRL B-24152T) could be distinguished from these two species and represented a new species within the genus Gordonia, for which the name Gordonia westfalica is proposed.
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Bacillus funiculus sp. nov., novel filamentous isolates from activated sludge.
More LessA novel filamentous Bacillus strain, NAF001T, was reported previously that produces endospores and spore-like resting cells; the latter outgrow by budding. Phylogenetic analysis based on 16S rDNA gene sequences reported in the same paper speculated on the proposal of a novel species for this isolate. This communication describes the DNA-DNA relatedness of strain NAF001T to various members of the genus Bacillus and its whole-cell fatty acid and quinone profiles, in order to authenticate the creation of a novel species, for which the name Bacillus funiculus sp. nov. is proposed. The type strain is NAF001T (= JCM 11201T = CIP 107128T). Further, features of the binding points between filaments of strain NAF001T that enable it to form extremely long filaments are captured by electron microscopy.
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Nesterenkonia lacusekhoensis sp. nov., isolated from hypersaline Ekho Lake, East Antarctica, and emended description of the genus Nesterenkonia.
More LessAn aerobic and heterotrophic isolate, designated IFAM EL-30T, was obtained from hypersaline Ekho Lake (Vestfold Hills, East Antarctica). The isolate consisted of Gram-positive cocci or short rods which occasionally exhibited branching. The organism was moderately halotolerant, required thiamin.HCI and was stimulated by biotin and nicotinic acid. It grew well with glucose, acetate, pyruvate, succinate, malate or glutamate, and hydrolysed DNA but not gelatin, starch or Tween 80. Nitrate was aerobically reduced to nitrite. Chemical analysis revealed diphosphatidylglycerol, phosphatidylglycerol, phosphatidylcholine and an unidentified glycolipid as the major polar lipids. The cellular fatty acids were predominantly of the anteiso and iso methyl-branched types, and the major menaquinone6 were MK-7 and MK-8. The peptidoglycan type was A4alpha, L-Lys-L-Glu. The DNA base ratio was 66.1 mol% G+C. Comparisons of 16S rRNA gene sequences showed that the unidentified organism was phylogenetically closely related to Nesterenkonia halobia, although a sequence divergence value of > 3% demonstrated that the organism represents a different species. On the basis of phenotypic and genotypic evidence, it is proposed that the unknown bacterium be designated as a new species of the genus Nesterenkonia, namely Nesterenkonia lacusekhoensis sp. nov., the type strain being IFAM EL-30T (= DSM 12544T = CIP 107030T). An emended description of the genus Nesterenkonia is given.
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Lactobacillus fuchuensis sp. nov., isolated from vacuum-packaged refrigerated beef.
More LessFour strains of a hitherto unknown bacterium isolated from vacuum-packaged refrigerated beef were characterized by using phenotypic and phylogenetic methods. The novel strains were Gram-positive, catalase-negative, psychrophilic, rod-shaped bacteria with lactic acid-homofermentative mechanism. Comparative 16S rDNA gene sequencing demonstrated that the unknown strains represent a novel subline within the genus Lactobacillus, close to but distinct from Lactobacillus curvatus and Lactobacillus sakei. The unknown strains were readily distinguished from all currently described members of the genus Lactobacillus by biochemical properties and SDS-PAGE whole-cell protein profiles. Based on phylogenetic and phenotypic evidence, it is proposed that the unknown bacterium be classified as Lactobacillus fuchuensis sp. nov. The type strain is strain B5M10T (= JCM 11249T = DSM 14340T).
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Clostridium phytofermentans sp. nov., a cellulolytic mesophile from forest soil.
More LessAn obligately anaerobic, mesophilic, cellulolytic bacterium, strain ISDgT, was isolated from forest soil. Cells of this isolate stained Gram-negative, despite possessing a Gram-positive cell-wall ultrastructure, and were motile, straight rods that formed spherical terminal spores that swelled the sporangium. Cellulose, pectin, polygalacturonic acid, starch, xylan, arabinose, cellobiose, fructose, galactose, gentiobiose, glucose, lactose, maltose, mannose, ribose and xylose supported growth. The major end products of fermentation were ethanol, acetate, CO2 and H2; formate and lactate were minor products. The optimum temperature for growth was 35-37 degrees C. Phylogenetic analyses based on 16S rRNA sequence comparisons showed that strain ISDgT was related to a group of anaerobes that included Clostridium herbivorans, Clostridium polysaccharolyticum and Clostridium populeti. The G+C content of this strain was 35.9 mol%. On the basis of numerous genotypic and phenotypic differences between strain ISDgT and its close relatives, strain ISDgT is proposed as a novel species in the genus Clostridium, for which the name Clostridium phytofermentans sp. nov. is proposed. The type strain is ISDgT (= ATCC 700394T).
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Streptococcus gallinaceus sp. nov., from chickens.
More LessThree isolates of an unknown Gram-positive, catalase-negative, chain-forming, coccus-shaped organism isolated from an outbreak of septicaemia in a flock of adult broiler parents were characterized by phenotypic and molecular taxonomic methods. Comparative 16S rRNA gene sequencing studies demonstrated that the bacterium represents a new subline within the genus Streptococcus, related to, albeit distinct from, Streptococcus acidominimus, Streptococcus ovis, Streptococcus suis and close relatives. The unknown bacterium was readily distinguished from all recognized streptococcal species by biochemical tests. Based on phylogenetic and phenotypic evidence, it is proposed that the unknown bacterium from chickens be classified as Streptococcus gallinaceus sp. nov. The type strain is CCUG 42692T (= CIP 107087T).
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Corynebacterium appendicis sp. nov.
A F Yassin, U Steiner and W LudwigA lipophilic, coryneform bacterium isolated from a human clinical specimen was characterized by phenotypic and molecular-taxonomic methods. Chemotaxonomic investigations revealed the presence of cell-wall chemotype IV and short-chain mycolic acids consistent with the genus Corynebacterium. The isolate could be distinguished from other members of the genus Corynebacterium by positive urease and catalase tests as well as its failure to produce acid from carbohydrates. Comparative 16S rRNA gene sequencing showed that this isolate constitutes a distinct subline within the genus Corynebacterium, displaying >3.0% sequence divergence from other known Corynebacterium species. Based on both phenotypic and phylogenetic evidence, it is proposed that this isolate be classified as a novel species, Corynebacterium appendicis sp. nov., represented by strain IMMIB R-3491T (= DSM 44531T = NRRL B-24151T).
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Exiguobacterium undae sp. nov. and Exiguobacterium antarcticum sp. nov.
More LessFour orange-pigmented strains from pond water (L1-L4) have been subjected to polyphasic taxonomic analyses. On the basis of ribotype analysis and Fourier-transform infrared spectroscopy, these strains form a genomically highly related group. 16S rDNA sequence analysis revealed 98.8% similarity between the 16S rDNA sequences of strains L2T and H2T, isolated previously from a microbial mat from Lake Fryxell, Antarctica. DNA-DNA reassociation values indicated the presence of two genomic clusters. While the DNA of strains L2T and L3 showed 100% DNA relatedness, strains L2T and H2T shared only 51% DNA relatedness. These two clusters differed in some phenotypic properties, e.g. utilization of melibiose, D-mannitol, adenosine 5'-monophosphate and uridine 5'-monophosphate, and in their fatty acid compositions. Based on the composition of isoprenoid quinones, peptidoglycan, polar lipids and fatty acids, these organisms are members of the genus Exiguobacterium. This is supported by 16S rDNA analyses, which revealed 97-98% similarity to Exiguobacterium acetylicum DSM 20416T and 93.2-93.8% similarity to Exiguobacterium aurantiacum DSM 6208T. E. acetylicum DSM 20416T, the closest phylogenetic neighbour, shows only 39% DNA similarity to strain L2T and 40% DNA similarity to strain H2T. Based on genomic distinctiveness and the clear differences in chemotaxonomy and physiology, two novel species are proposed, Exiguobacterium undae sp. nov. and Exiguobacterium antarcticum sp. nov.
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Caloramator viterbensis sp. nov., a novel thermophilic, glycerol-fermenting bacterium isolated from a hot spring in Italy.
More LessA moderately thermophilic, anaerobic bacterium, strain JW/MS-VS5T, was isolated from a mixed sediment/water sample of a hot spring at Bagnaccio (near Viterbo, Italy). The cells of this organism were straight to slightly curved rods, 0.4-0.6 x 2.03.0 microm in dimension. Cells occurred singly and stained Gram-positive. The temperature range for growth at pH(25C) 6.0 was 33-64 degrees C, the optimum being 58 degrees C. The pH(25C) range for growth was from 5.0 to 7.8, the optimum being 6.0-6.5. The substrates utilized included glycerol, glucose, fructose, mannose, galactose, sucrose, cellobiose, lactose, starch and yeast extract. Acetate and 1,3-propanediol were the only detectable organic products of glycerol fermentation; significant amounts of H2 were produced during growth. The strain was unable to grow autotrophically in the presence of H2 and CO2. The main products of glucose fermentation were CO2, H2, acetate and ethanol. Single amino acids, including serine, glutamine, threonine, leucine, methionine, aspartate, valine and histidine (but not arginine), served as carbon sources. Growth was completely inhibited by ampicillin, chloramphenicol, erythromycin, rifampicin and kanamycin at 100 microg ml(-1) and was retarded by streptomycin and tetracycline. The G+C content of the DNA was 32 mol% (HPLC). According to 16S rDNA sequence analysis, the isolate is located within the Gram-type positive Bacillus-Clostridium branch of the phylogenetic tree. On the basis of physiological properties and phylogenetic analysis, it is proposed that strain JW/MS-VS5T (the only, and type, strain) (= DSM 13723T = ATCC PTA 584T), constitutes the new species Caloramator viterbensis.
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Cellulosimicrobium variabile sp. nov., a cellulolytic bacterium from the hindgut of the termite Mastotermes darwiniensis.
More LessA novel cellulolytic and xylanolytic bacterium, strain MX5T, was isolated from the hindgut contents of the Australian termite Mastotermes darwiniensis (Froggatt). The isolate was a facultative anaerobe and had a Gram-positive cell-wall profile. The rod-shaped bacterium formed irregular coryneform and coccoid cells during growth. Phylogenetic analysis of the 16S rDNA provided evidence that the organism was closely related to the as-yet undescribed cellulolytic strain SR272 and the non-validly described species 'Cellulomonas pachnodae' as well as Promicromonospora citrea and Promicromonospora sukumoe. Strain MX5T was assigned to the genus Cellulosimicrobium on the basis of phylogenetic and chemotaxonomic criteria. The murein of strain MX5T contained the diamino acid lysine. N-Glycolylmuramic acid, mycolic acids and hydroxy fatty acids were absent. The major neutral sugar in the cell wall was galactose and the major quinone was menaquinone MK-9(H4). The predominant fatty acids were ai-C15:0, i-C15:0, i-C16:0 and C16:0. The G+C content of the DNA was in a range 70-72 mol%. On the basis of 16S rDNA sequence similarities and chemotaxonomic features, MX5T was clearly different from Cellulosimicrobium cellulans and other validly described species within this phylogenetic group. For this reason, a novel species is described, for which the name Cellulosimicrobium variabile sp. nov. is proposed.
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Thermobifida cellulolytica sp. nov., a novel lignocellulose-decomposing actinomycete.
Four actinomycete strains, isolated from the overheated region of manure compost, were assigned to the genus Thermobifida on the basis of morphological, physiological and biochemical characteristics. All strains produced single, ovoid, heat-sensitive spores on dichotomically branched aerial hyphae. On the basis of chemotaxonomic traits, these isolates showed strong affinity towards members of the genus Thermobifida. Cell-wall analysis revealed the presence of meso-diaminopimelic acid, but no other characteristic amino acids or sugars in the murein (cell wall type III). According to polar lipid analysis, all strains showed PL II-type phospholipid composition; phosphatidylethanolamine and glycolipid were detected together with some unidentified phospholipids. The isoprenoid quinone composition of the new isolates differed slightly from that of the other two Thermobifida species described thus far. The partial 16S rDNA sequence similarity of the four strains reached 99.8-100%, whereas a nearly complete 16S rDNA sequence of TB100T, the representative strain of this collection, showed only 97.4 and 97.8% similarity to the corresponding rDNA sequences of the type strains of Thermobifida fusca and Thermobifida alba, respectively. These four isolates constituted a homogeneous group with levels of DNA-DNA homology ranging from 94.6 to 99.1%. The DNA-DNA relative homology values of strain TB100T to Thermobifida fusca ATCC 27730T and Thermobifida alba DSM 43795T were 48.1 and 57%, respectively. On the basis of phenotypic, chemotaxonomic and genotypic data, the strains are assigned to a new species within the genus Thermobifida under the name Thermobifida cellulolytica sp. nov. The type strain is TB100T (= DSM 44535T = NCAIM B01997T).
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Actinomyces coleocanis sp. nov., from the vagina of a dog.
More LessA hitherto undescribed Actinomyces-like bacterium was isolated from the vagina of a dog. Biochemical testing and PAGE analysis of whole-cell proteins indicated that the isolate was phenotypically different from previously described Actinomyces species and related taxa. Sequencing of 165 rRNA showed that the unknown bacterium was distinct from all currently known Actinomyces species. Phylogenetically, the unidentified organism displayed a specific association with Actinomyces europaeus, but a sequence divergence of > 5% demonstrated that it represents a distinct species. Based on both phenotypic and 165 rRNA sequence considerations, it is proposed that the unknown strain from a dog be classified as a novel species, Actinomyces coleocanis sp. nov. The type strain is CCUG 41708T (= CIP 106873T).
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Bacillus okuhidensis sp. nov., isolated from the Okuhida spa area of Japan.
More LessTwo Gram-positive, endospore-forming, alkaliphilic bacteria were isolated from water samples obtained from the Okuhida hot spa area of Japan. The unknown bacteria were characterized using phenotypic and molecular taxonomic methods. On the basis of phylogenetic evidence and phenotypic distinctiveness, a new species, Bacillus okuhidensis sp. nov., is proposed. The type strain of Bacillus okuhidensis is GTC 854T (= JCM 10945T = DSM 13666T).
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Agrococcus baldri sp. nov., isolated from the air in the 'Virgilkapelle' in Vienna.
Five coccoid, Gram-positive strains were isolated from the air of the 'Virgilkapelle' in Vienna. A representative of these five strains, V-108T, shared 99.0 and 98.4% 16S rDNA sequence similarity, respectively, with Agrococcus jenensis DSM 9580 and Agrococcus citreus DSM 12453T. Colonies of the five strains were white when grown in the dark and turned yellow in the light. The strains displayed highly similar biochemical and physiological characteristics and showed only small differences in their protein patterns obtained after SDS-PAGE. Based on Fourier-transform infra-red (FT-IR) spectra, the five strains were grouped together and separated from the other members of the genus, A. jenensis and A. citreus. Chemotaxonomic characteristics analysed from selected members of the five isolates, including polar lipids, quinone systems, polyamine patterns, cell wall composition and fatty acid profiles, were in good agreement with those of the two species of the genus Agrococcus described to date. The G+C content of the genomic DNA was determined to be within the narrow range of 73.8-74.9 mol%. The results of DNA-DNA hybridization with A. citreus DSM 12453T and A. jenensis DSM 9580T, as well as differences in biochemical/physiological characteristics, peptidoglycan composition, fatty acids, polar lipid profiles and FT-IR spectra, demonstrated that the five isolates represent a novel species of the genus Agrococcus. The name Agrococcus baldri sp. nov. is proposed for the novel species, of which strain V-108T (= DSM 14215T = CCM 4953T) is the type strain.
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Sporanaerobacter acetigenes gen. nov., sp. nov., a novel acetogenic, facultatively sulfur-reducing bacterium.
A strictly anaerobic, moderately thermophilic, sporulating rod, designated strain Lup 33T, was isolated from an upflow anaerobic sludge blanket (UASB) reactor in Mexico. Strain Lup 33T possessed a few laterally inserted flagella, had a DNA G+C content of 32.2 mol % and grew optimally at pH 7.4 and 40 degrees C. Growth was observed at temperatures of up to 50 degrees C and was inhibited in the presence of 5% NaCl. Strain Lup 33T is heterotrophic and utilized some sugars, peptides and various single amino acids. Gelatin and casein were not used as energy sources. It performed the Stickland reaction and reduced elemental sulfur to sulfide. Acetate was the only fatty acid detected from glucose fermentation, whereas acetate together with isobutyrate and isovalerate were found as end products from peptone fermentation. Phylogenetically, strain Lup 33T branched with members of cluster XII of the order Clostridiales, with Clostridium hastiforme as the closest relative (similarity of 93%). On the basis of the phenotypic, genotypic and phylogenetic characteristics of the isolate, it is proposed as a novel species of a new genus, Sporanaerobacter acetigenes gen. nov., sp. nov. The type strain is strain Lup 33T (= DSM 13106T = CIP 106730T).
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Streptomyces thermospinisporus sp. nov., a moderately thermophilic carboxydotrophic streptomycete isolated from soil.
More LessA carboxydotrophic actinomycete strain, AT10T (= DSM 41779T = KCTC 9909T), was the subject of a polyphasic study. The morphological and chemical properties of the strain were found to be consistent with its assignment to the genus Streptomyces. The organism formed a distinct phyletic line within the 16S rDNA Streptomyces tree, and DNA-DNA relatedness experiments further confirmed that it formed a distinct genomic species. The strain was also distinguished from related species using phenotypic properties. Strain AT10T, therefore, merits species status within the genus Streptomyces; the name Streptomyces thermospinisporus sp. nov. is proposed for this new taxon.
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Microbacterium aerolatum sp. nov., isolated from the air in the 'Virgilkapelle' in Vienna.
Three rod-shaped, Gram-positive strains were isolated from the air of the chapel 'Virgilkapelle' in Vienna. A representative of these three strains, strain V-73T, shared the highest 16S rDNA sequence similarities with members of the genus Microbacterium, in particular Microbacterium foliorum, Microbacterium testaceum, Microbacterium esteraromaticum, Microbacterium keratanolyticum and Microbacterium arabinogalactanolyticum. The strains displayed almost identical biochemical and physiological characteristics and showed no differences in their protein patterns obtained after SDS-PAGE. On the basis of Fourier-transform infra-red (FT-IR) spectra and genomic fingerprints, the three strains were grouped together and separated from the other relevant members of the genus Microbacterium. The chemotaxonomic characteristics analysed, including polar lipids, quinone systems, cell wall composition and fatty acid profiles, were in good agreement with the characteristics described for the genus Microbacterium. The G+C content of the DNAs was determined to be in the narrow range 69.3-69.7 mol %. The results of DNA-DNA hybridization, biochemical/physiological characterization, ERIC-PCR-generated genomic fingerprints and FT-IR spectra demonstrated that the three isolates represent a novel species of the genus Microbacterium. The name Microbacterium aerolatum sp. nov. is proposed for the novel species, of which strain V-73T (= DSM 14217T = CCM 4955T) is the type strain.
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Streptosporangium subroseum sp. nov., an actinomycete with an unusual phospholipid pattern.
More LessA strain of Streptosporangium with an unusual phospholipid pattern was isolated from Yunnan Province, a region in China. The isolate, designated CY-7113T, was identified by morphological and physiological properties, cell chemistry, genomic DNA G+C content, DNA-DNA hybridization and phylogenetic analysis. Based on 16S rRNA gene sequencing, DNA-DNA hybridization, phenotypic characteristics and its unusual phospholipid pattern, it was concluded that strain CY-7113T belongs to a novel Streptosporangium species, for which the name Streptosporangium subroseum sp. nov. is proposed. Strain CY-7113T (= CCTCC 97008T = CRC 16302T) is the type strain.
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Final classification of Bisgaard taxon 9 as Actinobacillus arthritidis sp. nov. and recognition of a novel genomospecies for equine strains of Actinobacillus lignieresii.
More LessPhenotypic characterization of bacteria from diseased and healthy horses identified 18 isolates as Bisgaard taxon 9 and 11 isolates as Actinobacillus lignieresii. All strains of taxon 9 were alpha-galactosidase- and raffinose-positive and showed variable fermentation of (+)L-arabinose and (-)D-sorbitol. Strains of A. lignieresii were negative for these characteristics, with the exception of raffinose. Two strains from the (-)D-sorbitol-negative group of taxon 9 showed a 16S rRNA similarity of 99-6%, while 99.5% similarity was found between two strains of the (-)D-sorbitol-positive group. DNA-DNA hybridization between the two strains representing the (-)D-sorbitol-negative group showed 98% binding, and their closest relationship was to a strain of A. lignieresii (64%). The two strains of the (-)D-sorbitol-positive group showed 83% binding and were related to the (-)D-sorbitol-negative group at a 76% DNA binding level. Actinobacillus arthritidis sp. nov. is proposed for 12 strains of the (-)D-sorbitol-positive group. Actinobacillus genomospecies 2 is suggested for the six strains of the (-)D-sorbitol-negative group. Phenotypically, strains of A. arthritidis and Actinobacillus genomospecies 2 differ in (-)D-sorbitol fermentation and can be separated from Actinobacillus equuli by being trehalose-negative, while a positive reaction for alpha-galactosidase separates the taxa from A. lignieresii. The type strain of A. arthritidis, CCUG 24862T, was isolated from a joint of a horse. Three equine isolates of A. lignieresii that could not be separated from the type strain by means of phenotypic characteristics showed 98.6-100% 16S rRNA similarity, but only 96.4-96.7% similarity to the type strain. DNA-DNA hybridization between two strains of this group showed 92% binding but only 70% binding to the type strain of A. lignieresii. Consequently, these equine isolates of A. lignieresii represent a new genomospecies of Actinobacillus, suggested as genomospecies 1 because phenotypic characteristics are not presently available to separate it from the type strain of A. lignieresii.
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Taxonomic dissection of the Streptococcus bovis group by analysis of manganese-dependent superoxide dismutase gene (sodA) sequences: reclassification of 'Streptococcus infantarius subsp. coli' as Streptococcus lutetiensis sp. nov. and of Streptococcus bovis biotype 11.2 as Streptococcus pasteurianus sp. nov.
More LessThe taxonomic dissection of the Streptococcus bovis-Streptococcus equinus group was carried out upon obtaining sequences for the manganese-dependent superoxide dismutase gene (sodA) of the type strains of S. bovis, Streptococcus caprinus, S. equinus, Streptococcus gallolyticus, Streptococcus infantarius, Streptococcus macedonicus and Streptococcus waius. The sodA sequences of 29 streptococcal strains of animal and human origin that were related to S. bovis were also sequenced. A phylogenetic analysis of the sodA sequences revealed that the S. bovis-S. equinus group comprises five different clusters that correspond to five distinct species. The type strains of S. bovis and S. equinus were associated in the same cluster, corresponding to the species S. equinus. The type strains of S. caprinus, S. gallolyticus, S. macedonicus and S. waius were associated in the same cluster, which defined a single species containing S. gallolyticus and its junior synonym S. caprinus, and S. macedonicus and its junior synonym S. waius. The two subspecies thought to constitute the species S. infantarius, namely S. infantarius subsp. infantarius and 'S. infantarius subsp. coli', were located in two distinct clusters. One of these clusters defined the species S. infantarius and included the type strain of S. infantarius subsp. infantarius. The other cluster defined 'S. infantarius subsp. coli', leading to the proposal of its reclassification as the novel species Streptococcus lutetiensis (NEM 782T = CIP 106849T). The remaining cluster comprised all of the strains previously identified as belonging to S. bovis biotype 11.2, leading to the proposal to reassign these strains to the novel species Streptococcus pasteurianus (NEM 1202T = CIP 107122T). The results of the phylogenetic analysis were confirmed by DNA-DNA hybridization experiments, thus demonstrating that sequence databases of defined DNA targets, such as sodA, may constitute a valuable alternative approach for modern bacterial systematics.
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Weissella koreensis sp. nov., isolated from kimchi.
More LessA taxonomic study was carried out on two strains that came from kimchi, a traditional Korean fermented-vegetable food. The DNA G+C content of these strains was 37 mol %. Both strains contained Lys-Ala-Ser in the cell walls. On the basis of morphological, physiological and chemotaxonomic characteristics, together with data from 16S rDNA sequence comparisons and DNA-DNA reassociation, it is proposed that these strains represent a novel species of the genus Weissella, Weissella koreensis sp. nov. The type strain is strain S-5623T (= KCTC 3621T KCCM 41516T = JCM 11263T).
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Turicibacter sanguinis gen. nov., sp. nov., a novel anaerobic, Gram-positive bacterium.
More LessAn unknown, strictly anaerobic, Gram-positive, rod-shaped bacterium (strain MOL361T) was isolated from a blood culture of a febrile patient with acute appendicitis and characterized using phenotypic and molecular methods. Fatty acid analysis and biochemical examination indicated that the isolate most closely resembles members of the Gram-positive bacteria with low DNA G+C content. 16S rDNA sequencing revealed a relatively high overall similarity (97%) to an uncultured bacterium, but these two strains both exhibit low (<87%) 16S rDNA similarity to other bacteria. Phylogenetic analysis with different treeing methods showed that this strain forms a novel line of descent within the Gram-positive bacteria with low G+C content. Strain MOL361T is described as the type strain of a novel species within a new genus, Turicibacter sanguinis gen. nov., sp. nov.
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Rhizobium sullae sp. nov. (formerly 'Rhizobium hedysari'), the root-nodule microsymbiont of Hedysarum coronarium L.
This work is the completion of a series of reports describing the nitrogen-fixing bacterial symbionts of sulla (Hedysarum coronarium L., Leguminosae) and providing the grounds for their proposal as a new taxon. The introduction summarizes a large amount of previous evidence gathered on the physiology, genetics and ecology of such organisms, which have in the past been referred to provisionally as 'Rhizobium hedysari'. Upon adding 16S RNA sequencing, amplified rDNA restriction analysis of the rrn operon, DNA-DNA hybridization homology and analysis of low-molecular-mass RNA species, it is concluded that the group of strains that specifically nodulate sulla consists of a coherent set of isolates that differ from previously described rhizobia to an extent that warrants the constitution of the species boundary. The name Rhizobium sullae sp. nov. is proposed, with isolate 1S123T (=USDA 4950T = DSM 14623T) as the type strain.
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Thalassospira lucentensis gen. nov., sp. nov., a new marine member of the alpha-Proteobacteria.
A novel bacterium from the Mediterranean Sea was isolated under oligotrophic conditions at in situ temperature after prolonged continuous culture. The isolates were initially characterized by partial 16S rRNA gene sequencing. Similarity searches of one of the isolates, QMT2T, indicated high sequence identity to the well-characterized Rhodospirillum rubrum, [Aquaspirillum] itersonii and [Oceanospirillum] pusillum micro-organisms, which are representatives of the alpha-subclass of the Proteobacteria. The highest level of similarity of the complete 165 rRNA gene with respect to these microorganisms was 89%. Features such as the low similarities of 165 rRNA of QMT2T with its phylogenetically close neighbours, the distinct G+C content, and the differences in phenotypic features, including pigmentation, fatty acid composition, salt tolerance, the lack of bacteriochlorophyll a, and the capacity to use carbohydrates as carbon sources, are indicative of the novel nature of the isolate QMT2T among the alpha-Proteobacteria. This report describes the classification of strain QMT2T (= DSM 14000T = CECT 5390T) as a new genus and species, Thalassospira lucentensis gen. nov, sp. nov., in the family Rhodospirillaceae.
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Fulvimonas soli gen. nov., sp. nov., a gamma-proteobacterium isolated from soil after enrichment on acetylated starch plastic.
More LessSix deep-yellow-pigmented strains were isolated from soil after enrichment on plasticized acetylated starch granules as a source of carbon. They showed very similar and unique fatty acid profiles, consisting almost exclusively of branched fatty acids. The strains consisted of small, motile rods, were oxidase- and catalase-positive, did not ferment sugars and were able to depolymerize starch and suspended acetylated starch in overlayer plates. The 16S rDNA sequence of a representative strain, strain LMG 19981T, showed 96.7% sequence similarity to that of Rhodanobacter lindaniclasticus, 96.0% to that of Frateuria aurantia and less than 92% to sequences of other members of the gamma-Proteobacteria. Repetitive extragenic palindromic DNA PCR fingerprinting revealed two groups, representatives of which showed 93% DNA-DNA reassociation with each other and less than 10% with Frateuria aurantia LMG 1558T. On the basis of phenotypic characteristics and the G+C content of the DNA, the strains could be differentiated from Frateuria aurantia and Rhodanobacter lindaniclasticus. The name Fulvimonas soli gen. nov., sp. nov. is proposed, with the type strain LMG 19981T (= DSM 14263T).
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Psychrobacter submarinus sp. nov. and Psychrobacter marincola sp. nov., psychrophilic halophiles from marine environments.
Two novel psychrophilic, halophilic, Psychrobacter-like bacteria, strains KMM 225T and KMM 277T, were isolated from sea water and the internal tissues of an ascidian Polysyncraton sp. specimen, respectively, and characterized using a polyphasic approach, which included phenotypic, genotypic, chemotaxonomic and phylogenetic analyses. The novel marine isolates were Gram-negative, aerobic, coccoid, oxidase- and catalase-positive, non-pigmented, non-motile, psychrophilic and halophilic and they utilized a restricted spectrum of carbon sources. Strains KMM 225T and KMM 277T required sea water or sodium ions for growth and were tolerant of up to 12-15% (w/v) NaCl. Growth of strains KMM 225T and KMM 277T was observed at 4-35 and 7-35 degrees C, respectively. The DNA G+C contents of KMM 225T and KMM 277T were respectively 46-8 and 50.7 mol %. Comparison of almost complete 16S rDNA sequences of strains KMM 225T and KMM 277T revealed that both strains were phylogenetically most closely related to each other (99.9% sequence similarity) and slightly less related to Psychrobacter glacincola, with 97.2 and 97.8% similarity, respectively. DNA-DNA reassociation between KMM 225T and KMM 277T revealed 15% similarity, whereas similarity to other Psychrobacter species was 14-25%. Strains KMM 225T and KMM 277T differed from one another in their growth temperature, organic substrate utilization, antibiotic sensitivity and DNA G+C content. Both strains examined could be distinguished from all previously described Psychrobacter species by their physiological, genotypic and phylogenetic characteristics. On the basis of the physiological and molecular properties of the novel isolates, the names Psychrobacter submarinus sp. nov. (type strain KMM 225T = DSM 14161T) and Psychrobacter marincola sp. nov. (type strain KMM 277T = DSM 14160T) are proposed.
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Nautilia lithotrophica gen. nov., sp. nov., a thermophilic sulfur-reducing epsilon-proteobacterium isolated from a deep-sea hydrothermal vent.
A novel, strictly anaerobic, thermophilic sulfur-reducing bacterium, strain 525T, was isolated from tubes of the deep-sea hydrothermal vent polychaete Alvinella pompejana, collected on the East Pacific Rise (13 degrees N). This organism grew in the temperature range 37-68 degrees C, the optimum being 53 degrees C, and in the pH range 6.4-7.4, the optimum being 6.8-7.0. The NaCl range for growth was 0.8-5.0%, the optimum being 3.0%. Strain 525T grew lithoautotrophically with H2 as energy source, S0 as electron acceptor and CO2 as carbon source. Alternatively, strain 525T was able to use formate as an energy source. The G+C content of the genomic DNA was 34.7 mol%. Phylogenetic analysis of the 16S rDNA gene sequence placed strain 525T in the epsilon-subclass of the Proteobacteria, where it forms a deep cluster with recently isolated relatives. On the basis of phenotypic and phylogenetic differences between strain 525T and its closest phylogenetic relatives, it is proposed that the new isolate should be described as a member of a new genus, Nautilia, for which the name Nautilia lithotrophica gen. nov., sp. nov. is proposed. The type strain is strain 525T (= DSM 13520T).
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Reclassification of the only species of the genus Desulfomonas, Desulfomonas pigra, as Desulfovibrio piger comb. nov.
The growth characteristics, DNA G+C content and sequences of 16S rDNA and the transcribed 16S-23S rDNA internal spacer were determined for Desulfomonas pigra ATCC 29098T, Desulfovibrio desulfuricans subsp. desulfuricans strains Essex 6T (= ATCC 29577T) and MB (= ATCC 27774) and 'Desulfovibrio fairfieldensis' ATCC 700045. Despite phenotypic differences (shape and motility) between Desulfomonas pigra and Desulfovibrio strains, the molecular analysis suggests that Desulfomonas pigra should be reclassified within the genus Desulfovibrio. Thus, the reclassification is proposed of Desulfomonas pigra, the type and only species of the genus, as Desulfovibrio piger comb. nov., which implies the emendation of the description of the genus Desulfovibrio.
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Characterization of filamentous Eikelboom type 021N bacteria and description of Thiothrix disciformis sp. nov. and Thiothrix flexilis sp. nov.
The phenotypic and genotypic characteristics of 15 strains of Eikelboom type 021 N bacteria isolated from wastewater treatment plants were investigated. The strains shared many characters with Thiothrix species. However, the Eikelboom type 021N bacteria had only 88.3-92.0% 16S rDNA sequence similarity to members of the Thiothrix nivea group, including T. nivea, 'Thiothrix ramosa', Thiothrix unzii and Thiothrix fructosivorans, and were differentiated from them in sugar utilization and other properties, suggesting that the Eikelboom type 021N bacteria belong to species distinct from the T. nivea group. The 15 Eikelboom type 021N bacteria that were investigated were divided into three distinct groups (I to III) on the basis of their genotypic and phenotypic characteristics. The creation of two novel species is proposed, Thiothrix disciformis sp. nov. for the group I strains (type strain B3-1T = JCM 11364T = DSM 14473T) and Thiothrix flexilis sp. nov. for the group III strains (type strain EJ2M-BT = JCM 11135T = DSM 14609T). Thiothrix eikelboomii AP3T was included in group II and shared many characters with the other group II strains. The inclusion of all group II strains within the species T. eikelboomii is proposed,together with emendation of the description of T. eikelboomii.
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Caminibacter hydrogeniphilus gen. nov., sp. nov., a novel thermophilic, hydrogen-oxidizing bacterium isolated from an East Pacific Rise hydrothermal vent.
A novel thermophilic, anaerobic, hydrogen-oxidizing bacterium, designated strain AM1116T, was isolated from an East Pacific Rise hydrothermal vent sample. The cells were rod-shaped (1.01-5 x 0.5 microm), motile with polar flagella. They grew at temperatures between 50 and 70 degrees C (optimum 60 degrees C; doubling time approximately 1.5 h), at between pH 5.0 and 7.5 (optimum around pH 5.5-6.0) and in between 10 and 40 g NaCl l(-1) (optimum 20-25 g l(-1)). Cells grew chemolithoautotrophically in a H2/CO2 atmosphere (80:20; 200 kPa). Poor heterotrophic growth was observed on complex organic substrates. Elemental sulphur and nitrate served as electron acceptors, respectively yielding hydrogen sulphide and ammonia (doubling times were equal with the two electron acceptors). In contrast, when cystine was used as electron acceptor, growth was poor. The G+C content of the genomic DNA was 29 +/- 1 mol %. Phylogenetic analyses of the 16S rRNA gene located the strain within the epsilon-Proteobacteria, in the bacterial domain. On the basis of 16S rDNA sequence comparisons, physiological and biochemical characteristics, it is proposed that the isolate should be described as the type species of a new genus, Caminibacter gen. nov., as Caminibacter hydrogeniphilus sp. nov. The type strain is strain AM1116T (= DSM 14510T = CIP 107140T).
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Gelidibacter mesophilus sp. nov., a novel marine bacterium in the family Flavobacteriaceae.
More LessTwo Gram-negative, aerobic, heterotrophic, marine bacteria, isolated from Mediterranean sea water off the coast near Valencia (Spain), were the object of this study. These non-motile, yellow-pigmented, rod-shaped strains have been studied by means of DNA-DNA hybridization, 16S rRNA sequencing and cultural and physiological features. Phylogenetic analysis showed that both strains belong to the phylum Cytophaga-Flavobacterium-Bacteroides, and their closest neighbour is the psychrophilic bacterium Gelidibacter algens. The two strains differ from G. algens in their mesophilic behaviour, hydrolytic pattern and use of different carbon sources. There is 31% DNA-DNA hybridization between the proposed type strain and G. algens, and both isolates show 97.5% 16S rDNA similarity to G. algens. They represent a novel species of the genus Gelidibacter, for which the name Gelidibacter mesophilus sp. nov. is proposed, with strain 2SM29T (= CECT 5103T = DSM 14095T) as the type strain.
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Marinitoga piezophila sp. nov., a rod-shaped, thermo-piezophilic bacterium isolated under high hydrostatic pressure from a deep-sea hydrothermal vent.
A thermophilic, anaerobic, piezophilic, chemo-organotrophic sulfur-reducing bacterium, designated as KA3T, was isolated from a deep-sea hydrothermal chimney sample collected at a depth of 2630 m on the East-Pacific Rise (13 degrees N). When grown under elevated hydrostatic pressure, the cells are rod-shaped with a sheath-like outer structure, motile, have a mean length of 1-1.5 microm and stain Gram-negative. They appear singly or in short chains. When grown at lower, or atmospheric, pressures, the cells elongate and become twisted. Growth is enhanced by hydrostatic pressure; the optimal pressure for growth is 40 MPa (26 MPa pressure at sampling site). The temperature range for growth is 45-70 degrees C, the optimum being around 65 degrees C (doubling time is approximately 20 min at 40 MPa). Growth is observed from pH 5 to pH 8, the optimum being at pH 6. The salinity range for growth is 10-50 g NaCl l(-1), the optimum being at 30 g l(-1). The isolate is able to grow on a broad spectrum of carbohydrates or complex proteinaceous substrates, and growth is stimulated by L-cystine and elemental sulfur. The G+C content of the genomic DNA is 29 +/- 1 mol%. According to phylogenetic analysis of the 16S rDNA gene, the strain is placed within the order Thermotogales, in the bacterial domain. On the basis of 16S rDNA sequence comparisons and morphological, physiological and genotypic characteristics, it is proposed that the isolate be described as a novel species of the genus Marinitoga, with Marinitoga piezophila sp. nov. as the type species. The type strain is KA3T (= DSM 14283T = JCM 11233T).
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Geovibrio thiophilus sp. nov., a novel sulfur-reducing bacterium belonging to the phylum Deferribacteres.
More LessStrain AAFu3T (= DSM 11263T = ATCC BAA-311T), a Gram-negative, non-sporulating bacterium, was isolated from a methanogenic mixed culture growing with acetone, in which acetate was the major intermediate. The cells of strain AAFu3T were slender spirilla, usually of less than one turn, and were motile by means of a single polar flagellum. The cells contained c-type cytochromes and the G+C content of the genomic DNA was 50.2 mol%. Sulfur, nitrate, fumarate, DMSO and oxygen (microaerophilically) were used as electron acceptors, but sulfate, sulfite, thiosulfate and ferric iron were not. Sulfide, hydrogen, formate and acetate acted as electron donors for respiratory growth, while fumarate, maleate and L-malate supported fermentative growth. Neither fermentative nor respiratory growth was supported by carbohydrates, fatty acids more than two carbons long, alcohols or amino acids. The strain was a mesophile. Comparative sequence analysis of the 165 rRNA gene and comparison of phenotypic characteristics showed that strain AAFu3T is closely related to Geovibrio ferrireducens, within the phylum Deferribacteres. Strain AAFu3T was designated as the type strain of a new species, for which the name Geovibrio thiophilus is proposed.
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Persephonella marina gen. nov., sp. nov. and Persephonella guaymasensis sp. nov., two novel, thermophilic, hydrogen-oxidizing microaerophiles from deep-sea hydrothermal vents.
More LessTwo thermophilic, strictly chemolithoautotrophic, microaerophilic, hydrogen-oxidizing members of the Bacteria designated strain EX-H1T and strain EX-H2T were isolated from two separate deep-sea hydrothermal vent sites at 9 degrees N 104 degrees W in the Pacific Ocean and Guaymas Basin. The motile 2-4-microm-long rods were Gram-negative and non-sporulating. The temperature range for growth was between 55 and 80 degrees C for EX- H1T (optimum at 73 degrees C) and 55-75 C for EX-H2T (optimum at 70 C). Both strains grew fastest at 2.5% (w/v) NaCl and at pH 6, although growth was observed from pH 4.7 to pH 7.5. EX-H1T and EX-H2T were able to use elemental sulfur, thiosulfate or hydrogen as an electron donor, and oxygen (2-3%, v/v) or nitrate as an electron acceptor. EX-H1T was also able to use elemental sulfur as an electron acceptor. EX-H1T and EX-H2T further differed in their genomic G+C content (38.5 and 37.4 mol%, respectively) and 16S rRNA sequences (4% difference). Maximum-likelihood analysis of the 16S rRNA phylogeny placed both isolates within the Aquificales as a distinct lineage and showed them to be only about 85% similar to Aquifex pyrophilus. On the basis of phenotypic and phylogenetic characteristics, it is proposed that EX-H1T and EX-H2T belong to a new genus within the Aquificales, namely Persephonella gen. nov. It is further proposed that EX-H1T be named Persephonella marina sp. nov., the type species of the genus, and that EX-H2T be named Persephonella guaymasensis sp. nov., a second species in this genus.
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Thermotoga lettingae sp. nov., a novel thermophilic, methanol-degrading bacterium isolated from a thermophilic anaerobic reactor.
More LessA novel, anaerobic, non-spore-forming, mobile, Gram-negative, thermophilic bacterium, strain TMOT, was isolated from a thermophilic sulfate-reducing bioreactor operated at 65 C with methanol as the sole substrate. The G+C content of the DNA of strain TMOT was 39.2 mol%. The optimum pH, NaCl concentration, and temperature for growth were 7.0, 1.0%, and 65 degrees C, respectively. Strain TMOT was able to degrade methanol to CO2 and H2 in syntrophic culture with Methanothermobacter thermautotrophicus AH or Thermodesulfovibrio yellowstonii. Thiosulfate, elemental sulfur, Fe(III) and anthraquinone-2,6-disulfonate were able to serve as electron acceptors during methanol degradation. In the presence of thiosulfate or elemental sulfur, methanol was converted to CO2 and partly to alanine. In pure culture, strain TMOT was also able to ferment methanol to acetate, CO2 and H2. However, this degradation occurred slower than in syntrophic cultures or in the presence of electron acceptors. Yeast extract was required for growth. Besides growing on methanol, strain TMOT grew by fermentation on a variety of carbohydrates including monomeric and oligomeric sugars, starch and xylan. Acetate, alanine, CO2, H2, and traces of ethanol, lactate and alpha-aminobutyrate were produced during glucose fermentation. Comparison of 16S rDNA genes revealed that strain TMOT is related to Thermotoga subterranea (98%) and Thermotoga elfii (98%). The type strain is TMOT (= DSM 14385T = ATCC BAA-301T). On the basis of the fact that these organisms differ physiologically from strain TMOT, it is proposed that strain TMOT be classified as a new species, within the genus Thermotoga, as Thermotoga lettingae.
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Candida davenportii sp. nov., a potential soft-drinks spoilage yeast isolated from a wasp.
More LessDuring a survey of yeast ecology in a soft-drinks production facility, a dead wasp was removed from the sampling tap of an external sugar-syrup storage tank. A yeast isolated from the dead wasp was found to be similar, although not identical, in its physiological characteristics to Candida lactis-condensi and Candida stellata. Sequence analysis of the 26S rDNA D1/D2 variable domain revealed that this isolate was most closely related to C stellata, but differed sufficiently in its D1/D2 sequence to indicate that it belonged to a separate species. The yeast species has been named Candida davenportii sp. nov.; the type strain is NCYC 3013T (= CBS 9069T). C davenportii sp. nov. was osmotolerant, moderately preservative-resistant and able to grow in very acidic conditions, i.e. pH 14. This yeast grew well in fruit-containing soft drinks, cola-type beverages and a synthetic soft drink and is therefore a potential cause of spoilage of soft drinks and other sugary food products. Other related yeast species in the same taxonomic clade as C davenportii sp. nov. are also osmotolerant, growing in < 50% (w/v) sugar. Many of these species are associated with insects, specifically bees, bumblebees and leafcutter bees, and many have been reported as the causative agent of spoilage of sugary foods, such as condensed milk, fruit juices and concentrates. It is proposed that C davenportii sp. nov. and other closely related yeasts are primarily associated with Aculeates (bees and wasps). In turn, bees and wasps are attracted by sugary residues in foods such as fruit juices and concentrates, forming the source of infection of these yeasts and thus instigating spoilage.
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Phylogeny of the genus Simonsiella and other members of the Neisseriaceae.
More Less16S rDNA was sequenced from 16 strains of the oral commensal Simonsiella and was used to assess relationships between Simonsiella strains and other members of the Neisseriaceae. In all analyses, Simonsiella strains grouped according to established species designations and the mammalian hosts from which they were isolated. The commensals from cats and dogs formed a monophyletic group. The monophyly of the genus Simonsiella, however, could be neither supported nor rejected; deep nodes in the trees were unstable depending on the phylogenetic method or on the particular sequences used in the analysis. Instabilities may be attributable to frequent gene transfer between Neisseria or other members of the Neisseriaceae and Simonsiella.
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Conserved and variable domains within divergent rnase P RNA gene sequences of Prochlorococcus strains.
More LessRNase P RNA gene (rnpB) sequences were PCR-amplified from different members of the Prochlorococcus group. Aligned nucleotide sequences revealed a variance of up to 27% for rnpB. Comparative secondary structure analysis showed that domains P12, P18 and P19 of these novel ribozyme sequences in particular are highly divergent. Thus, these regions in RNase P RNA might serve as potential targets for deoxyoligonucleotide primers for the identification of specific genotypes of Prochlorococcus and for probing field populations. Phylogenetic trees constructed from RNase P RNA sequences were similar to, but not fully congruent with, those derived previously using sequences of the 16S rRNA gene. However, the application of rnpB sequences allowed a better resolution within clades of very closely related genotypes. As is known from 16S rRNA-based phylogenetic trees, sequences from individual strains clustered according to their physiology and the conditions at the original site of isolation, rather than their geographical origin. All sequences obtained from high-light-adapted strains formed a single coherent clade, as did the four sequences from low-light-adapted strains that were previously isolated from the North Atlantic and the subtropical North Pacific. This suggests a remarkable genetic stability of Prochlorococcus genotypes that thrive under identical ecological conditions.
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Phylogenetic analysis of Prevotella nigrescens, Prevotella intermedia and Porphyromonas gingivalis clinical strains reveals a clear species clustering.
More LessPrevotella nigrescens, Prevotella intermedia and Porphyromonas gingivalis are oral pathogens from the family Bacteroidaceae, regularly isolated from cases of gingivitis and periodontitis. In this study, the phylogenetic variability of these three bacterial species was investigated by means of 16S rRNA (rrs) gene sequence comparisons of a set of epidemiologically and geographically diverse isolates. For each of the three species, the rrs gene sequences of 11 clinical isolates as well as the corresponding type strains was determined. Comparison of all rrs sequences obtained with those of closely related species revealed a clear clustering of species, with only a little intraspecies variability but a clear difference in the rrs gene with respect to the next related taxon. The results indicate that the three species form stable, homogeneous genetic groups, which favours an rrs-based species identification of these oral pathogens. This is especially useful given the 7% sequence divergence between Prevotella intermedia and Prevotella nigrescens, since phenotypic distinction between the two Prevotella species is inconsistent or involves techniques not applicable in routine identification.
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Phylogenetic analyses of nitrogen-fixing cyanobacteria from the Baltic Sea reveal sequence anomalies in the phycocyanin operon.
More LessThe examination of molecular phylogenies of cyanobacteria and other micro-organisms is increasing dramatically. The use of a single locus in these studies leaves the resulting phylogenies unconfirmed. In this study, the partial sequences of two loci containing segments of protein-encoding genes, the hetR and the phycocyanin locus (PC-IGS), were examined. Laboratory strains and natural populations of the heterocyst-forming cyanobacteria Anabaena, Aphanizomenon and Nodularia from the Baltic Sea were used, in total 41 sequences were determined and their phylogenies were analysed with maximum-likelihood methods. The hetR phylogenies suggested that the planktonic Aphanizomenon and Nodularia each comprise one species, while there were numerous Anabaena species present in the Baltic Sea. In the case of Nodularia, the PC-IGS phylogenies were incongruent with this and suggested that several lineages of Nodularia plankton species existed. In the hetR phylogeny, the floating and nodularin-producing strains of Nodularia were grouped together. For both the hetR and PC-IGS loci of cultured species of Nodularia their molecular phylogeny did not correspond well with the affiliation suggested by morphology. In sequences derived from species of Anabaena and Aphanizomenon the PC-IGS and hetR phylogenies were congruent, suggesting that Aphanizomenon sp. from the Baltic Sea is genetically distinct from both Aphanizomenon flos-aquae from lakes and Aphanizomenon sp. TR183 from the Baltic Sea. In both Nodularia and Anabaena/Aphanizomenon, the PC-IGS sequences showed a significant degree of either recombination events or selection, while none was detected within the hetR sequences. This is the first study comprising the phylogenies of multiple loci from all heterocystous cyanobacteria from the Baltic Sea and shows that earlier results using the PC-IGS locus should be interpreted cautiously in the absence of a confirmation using a second locus.
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Conservation of the unique rickettsial rRNA gene arrangement in Anaplasma.
More LessThe organization of the rRNA genes of Anaplasma marginale, the type species of the genus Anaplasma, was identified to determine if the atypical rRNA gene arrangement identified in rickettsiae preceded divergence of the order Rickettsiales into the families Anaplasmataceae and Rickettsiaceae. The rRNA genes are encoded by two unlinked units, each present in a single copy per A. marginale genome. The 16S rRNA gene is separated from the linked 23S and 5S rRNA genes by a minimum of 100 kb. Similar to species belonging to the genus Rickettsia, the typical bacterial 16S-23S spacer region containing tRNA genes has been lost in A. marginale. In contrast, the fmt gene located upstream of the 23S rRNA gene in most Rickettsia spp. is not maintained in A. marginale, consistent with the fmt arrangement being a relatively late event in the evolution of rickettsial species.
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New genus-specific primers for the PCR identification of novel isolates of the genera Nocardiopsis and Saccharothrix.
More LessThe taxonomic position of the genera Saccharothrix and Nocardiopsis has evolved in recent years to accommodate an increasing number of actinomycete strains that cannot be clearly distinguished by morphological characters. More recently, the taxonomic reorganization of the genus Saccharothrix has determined the creation of new, related genera, increasing the complexity of the identification of this taxon. Nevertheless, today these genera can still only be identified by applying chemotaxonomic and molecular criteria, and no other tools are available for the rapid distinction of members of the two genera. Phylogenetic analysis based on 16S rDNA nucleotide sequences of reference strains has shown that both genera represent complete distinct lineages within the order Actinomycetales. Differences in the nucleotide sequences of the 16S rDNAs of reference strains were used to design two pairs of genus-specific primers to identify novel members of the genera Nocardiopsis and Saccharothrix by PCR amplification. The genus specificity of these primers was validated with reference strains as well as with wild-type isolates that exhibited morphological characteristics common to both genera. The diversity and taxonomic position of the isolates identified with these tools is also discussed.
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