Extremely 'vanadiphilic' multiply metal-resistant and halophilic aerobic anoxygenic phototrophs, strains EG13 and EG8, from hypersaline springs in Canada.

Two pinkish peach-colored strains of obligately aerobic phototrophic bacteria, EG13 and EG8, were isolated from a saline spring effluent stream in west central Manitoba, Canada. The strains possessed bacteriochlorophyll a incorporated into a typical purple bacterial light-harvesting complex 1 (870 nm) and reaction center (801 nm). Analysis of 16S rRNA gene sequences indicated 100% identity among the isolates and 99% similarity to Roseovarius tolerans EL-172(T). The strains were physiologically well adapted to high salinity (0-22%), fluctuating pH (7-12) and temperature (7-40 °C) of the exposed hypersaline stream of East German Creek. EG8 and EG13 were also highly resistant to the toxic metal(loid) oxyanions tellurite, selenite and metavanadate (≥1000 µg/ml each). Most intriguingly, growth and pigment production of EG13 on glutamate minimal medium was stimulated by 1000-10000 µg/ml of sodium metavanadate compared to metal-free conditions. Phylogenetic analysis and phenotypic properties such as pigment composition and morphology indicate close relatedness to Roseovarius genus.

Reclassification of Koreibacter algae as a later heterotypic synonym of Paraoerskovia marina and emended descriptions of the genus Paraoerskovia Khan et al. 2009 and of Paraoerskovia marina Khan et al. 2009.

16S rRNA gene sequences deposited for the type strains of Paraoerskovia marina (CTT-37(T); GenBank accession no. AB445007) and Koreibacter algae (DSW-2(T); FM995611) show a similarity of 100 %. Consequently, the type strains were subjected to a polyphasic recharacterization under direct comparison in order to clarify their taxonomic position. PvuII RiboPrint patterns and quantitative ratios of cellular fatty acids revealed strain-specific differences between P. marina DSM 21750(T) ( = CTT-37(T)) and K. algae DSM 22126(T) ( = DSW-2(T)). The percentage of DNA-DNA binding of 94 % indicated that the two type strains belong to the same genomospecies. Agreement in the peptidoglycan structure and polar lipid pattern, highly similar fatty acid profiles and MALDI-TOF mass spectra, the ability to produce acid from the same carbon sources, corresponding enzymic activities and DNA G+C contents of 70.8 ± 0.3 mol%, in addition to the consistent characteristics reported in the original descriptions, support the view that the two strains should be affiliated to the same species. According to Rules 38 and 42 of the Bacteriological Code, Koreibacter algae should be reclassified as later heterotypic synonym of Paraoerskovia marina, and the descriptions of the genus Paraoerskovia Khan et al. 2009 and of Paraoerskovia marina Khan et al. 2009 are emended accordingly.

Chromocurvus halotolerans gen. nov., sp. nov., a gammaproteobacterial obligately aerobic anoxygenic phototroph, isolated from a Canadian hypersaline spring.

A strain EG19(T) of aerobic bacteria able to form pleomorphic cells was isolated from a brine spring runoff stream in the west central region of the province of Manitoba, Canada. The pale pinkish purple strain contained bacteriochlorophyll a incorporated into light-harvesting I and reaction center complexes. Its inability to grow under anaerobic illuminated conditions prompted designation as a member of the functional group known as aerobic anoxygenic phototrophic bacteria. Phylogenetic analysis of the 16S rRNA gene sequence revealed that it belonged to the Gammaproteobacteria, forming a distinct branch of phototrophs distantly related to most described aerobic anoxygenic phototrophs, quite marginally related (95.6%) both to the only other described gammaproteobacterial aerobic phototroph, Congregibacter litoralis, and also to nonphototrophs in the genus Haliea (95.1-96.1%). Physiological tests demonstrated tolerance profiles to salinity (0-18% NaCl), pH (7-12), and temperature (7-40°C) consistent with survival in a shallow hypersaline stream on the exposed, vegetation-depleted salt playa of its native East German Creek. Phylogenetic data and phenotypic properties such as pigment composition, morphology, and physiology support the proposal of the novel genus and species Chromocurvus halotolerans gen. nov., sp. nov., with EG19(T) (=DSM 23344(T), =VKM B-2659(T)) as the type strain.

An alphaproteobacterium capable of both aerobic and anaerobic anoxygenic photosynthesis but incapable of photoautotrophy: Charonomicrobium ambiphototrophicum, gen. nov., sp. nov.

A facultatively aerobic deep brown coccoid to ovoid bacterium, strain EG17(T), was isolated from a saline effluent stream in the NaCl-dominated brine spring system known as East German Creek in the province of Manitoba, Canada. The strain produced BChl a incorporated into a functional reaction center and two light-harvesting complexes with absorption peaks at 802, 850, and 879 nm. EG17(T) is the first reported anoxygenic phototroph capable of photoheterotrophic growth under both oxic and anoxic conditions. It yielded proportionally the greatest aerobic photosynthetic biomass under oligotrophic conditions. The results of 16S rRNA gene sequence comparisons revealed that EG17(T) was related most closely to the aerobic anoxygenic phototrophs Roseibacterium elongatum (98.3%) and quite distantly to both Dinoroseobacter shibae (95.2%) and Roseicyclus mahoneyensis (94.7%). The DNA G + C content was 65.6 mol%. On the basis of the unique dual aerobic/anaerobic photosynthetic capability, the distinctive spectrophotometric absorption of the photosynthetic apparatus, diagnostic physiological and biochemical traits, and the moderate phylogenetic separation between EG17(T) and its nearest relatives, it is concluded that this microorganism should be classified as a novel genus and species, Charonomicrobium ambiphototrophicum gen. nov., sp. nov., with EG17(T) as the type strain.

Aeromonas rivuli sp. nov., isolated from the upstream region of a karst water rivulet.

Two freshwater isolates (WB4.1-19(T) and WB4.4-101), sharing 99.9 % 16S rRNA gene sequence similarity, were highly related to Aeromonas sobria (99.7 % similarity; 6 bp differences). A phylogenetic tree derived from a multi-locus phylogenetic analysis (MLPA) of the concatenated sequences of five housekeeping genes (gyrB, rpoD, recA, dnaJ and gyrA; 3684 bp) revealed that both strains clustered as an independent phylogenetic line next to members of Aeromonas molluscorum and Aeromonas bivalvium. The DNA-DNA reassociation value between the two new isolates was 89.3 %. Strain WB4.1-19(T) had a DNA-DNA relatedness value of <70 % with the type strains of the other species tested. Phenotypic characterization differentiated the two novel strains from all other type strains of species of the genus Aeromonas. It is concluded that the two new strains represent a novel species of the genus Aeromonas, for which the name Aeromonas rivuli sp. nov. is proposed, with the type strain WB4.1-19(T) (=CECT 7518(T)=DSM 22539(T)=MDC 2511(T)).

Bacterial diversity in the haloalkaline Lake Elmenteita, Kenya.

Lake Elmenteita is one of the alkaline saline lakes within the Kenyan Rift valley. The lake is situated on the floor of the Kenyan Rift Valley at 1,776 m above sea level and has no direct outlet. The microbial diversity of the lake was investigated using a culture-independent approach. Five different sampling points were selected randomly within the lake. Wet sediments and water samples were collected from each sampling point. In addition, dry mud cake was collected from three points where the lake had dried. DNA was extracted from the samples and the 16S rRNA genes amplified using universal primers for Bacteria. Thirteen clone libraries were constructed using the PCR amplified 16S rRNA genes. A total of 1,663 clones were picked. Representative clones were selected using ARDRA technique for sequencing. 655 partial and non-chimeric clone sequences indicated the presence of 37 orders in the Domain Bacteria. Cyanobacteria were the most abundant clones in terms of numbers whereas members of the phylum Firmicutes group were the second in terms of numbers but the most diverse in terms of genera represented. All clones affiliated to the class Betaproteobacteria originated from DNA obtained from the water samples. Analysis using BLAST showed that 93.1% of the sequenced clones had similarity values below 98% to both cultured and as yet uncultured bacteria, resulting in 596 phylotypes. Therefore, it can be concluded that Lake Elmenteita harbours phylogenetically diverse groups of bacteria involved in complex metabolic interactions within the Lake's ecosystem.

Reclassification of Aurantimonas altamirensis (Jurado et al. 2006), Aurantimonas ureilytica (Weon et al. 2007) and Aurantimonas frigidaquae (Kim et al. 2008) as members of a new genus, Aureimonas gen. nov., as Aureimonas altamirensis gen. nov., comb. nov., Aureimonas ureilytica comb. nov. and Aureimonas frigidaquae comb. nov., and emended descriptions of the genera Aurantimonas and Fulvimarina.

Members of the genera Aurantimonas and Fulvimarina have largely been described on the basis of 16S rRNA gene sequence analyses, biochemical tests and limited chemotaxonomic data. Examination of the polar lipid compositions of members of these two genera indicated that although the patterns were similar with regards the phospholipid and amino lipid compositions, there were clear differences in the presence or absence of the glycolipid sulfoquinovosyldiacylglycerol (SQDG). This glycolipid was absent in members of the species Aurantimonas coralicida and Fulvimarina pelagi but was present in Aurantimonas altamirensis, Aurantimonas ureilytica and Aurantimonas frigidaquae. These results are also consistent with the 16S rRNA sequence-based grouping. We therefore propose that the genus Aurantimonas be divided further to reflect this additional information. Thus, it is recommended that Aurantimonas altamirensis, Aurantimonas ureilytica and Aurantimonas frigidaquae are transferred to a new genus, Aureimonas gen. nov., as Aureimonas altamirensis gen. nov., comb. nov. (type strain S21B(T) = CECT 7138(T) = CIP 109525(T) = KCTC 22106(T) = LMG 23375(T) = DSM 21988(T)), Aureimonas ureilytica comb. nov. (type strain 5715S-12(T) = KACC 11607(T) = DSM 18598(T) = CIP 109815(T)) and Aureimonas frigidaquae comb. nov. (type strain CW5(T) = KCTC 12893(T) = JCM 14755(T) = DSM 21987(T)). The type species of the new genus is Aureimonas altamirensis. Additionally, emended descriptions of the genera Aurantimonas and Fulvimarina are provided.

Isolation and characterisation of bacteria from the haloalkaline Lake Elmenteita, Kenya.

Culture-independent studies show that soda lake environments harbour diverse groups of bacteria and archaea. In this study different enrichment and isolation media were used in an attempt to isolate novel groups of bacteria from Lake Elmenteita. Different media were prepared using filter-sterilised water from the lake. The isolates recovered were purified on tryptic soy agar supplemented with 1% sodium carbonate and 4% sodium chloride. Phylogenetic analysis of 181 partial 16S rRNA gene sequences with excellent quality showed that the majority of the isolates were affiliated to the class Gammaproteobacteria and to the genus Bacillus. Isolates from the genus Halomonas and Bacillus constituted 37 and 31% of the total sequenced isolates, respectively. Other groups recovered were related to Marinospirillum, Idiomarina, Vibrio, Enterococcus, Alkalimonas, Alkalibacterium, Amphibacillus, Marinilactibacillus and the actinobacteria Nocardiopsis and Streptomyces. Fifty-one different genera were represented with 31 and 15 cultures scoring with their nearest neighbour similarities below 98 and 97%, respectively. Some novel taxa were identified which had not been isolated previously from the soda environment. The results show that the use of different media with varying compositions can help retrieve novel bacterial diversity from the soda lake environment.

Ochrobactrum ciceri sp. nov., isolated from nodules of Cicer arietinum.

A Gram-staining-negative, aerobic, rod-shaped, non-spore-forming bacterial strain, Ca-34(T), was isolated from nodules of chickpea (Cicer arietinum) in Pakistan and studied for its taxonomic affiliation. The almost full-length 16S rRNA gene sequence showed highest similarities to those of strains of the genus Ochrobactrum. Based on results of MALDI-TOF MS and 16S rRNA gene sequence similarity (98.6 %), strain Ca-34(T) and Ochrobactrum intermedium LMG 3301(T) are phylogenetic neighbours; the two strains shared DNA-DNA relatedness of 64 %. The fatty acid profile [predominantly C(18 : 1)omega7c (67.7 %) and C(19 : 0) cyclo omega8c (19.6 %)] also supported the genus affiliation. Metabolically, strain Ca-34(T) differed from other type strains of Ochrobactrum in many reactions and from all type strains in testing positive for gelatin hydrolysis and in testing negative for assimilation of alaninamide and l-threonine. Based on phenotypic and genotypic data, we conclude that strain Ca-34(T) represents a novel species, for which we propose the name Ochrobactrum ciceri sp. nov. (type strain Ca-34(T) =DSM 22292(T) =CCUG 57879(T)).

Aeromonas aquariorum sp. nov., isolated from aquaria of ornamental fish.

During a survey to determine the prevalence of Aeromonas strains in water and skin of imported ornamental fish, 48 strains presumptively identified as Aeromonas were isolated but they could not be identified as members of any previously described Aeromonas species. These strains were subjected to a polyphasic approach including phylogenetic analysis derived from gyrB, rpoD and 16S rRNA gene sequencing, DNA-DNA hybridization, MALDI-TOF MS analysis, genotyping by RAPD and extensive biochemical and antibiotic susceptibility tests in order to determine their taxonomic position. Based on the results of the phylogenetic analyses and DNA-DNA hybridization data, we describe a novel species of the genus Aeromonas, for which the name Aeromonas aquariorum sp. nov. is proposed, with strain MDC47T (=DSM 18362T =CECT 7289T) as the type strain. This is the first Aeromonas species description based on isolations from ornamental fish.

Xenorhabdus antibiotics: a comparative analysis and potential utility for controlling mastitis caused by bacteria.

AIMS: The role of antibiotics produced by bacterial symbionts of entomopathogenic nematodes is to suppress growth of microbes in the soil environment. These antibiotics are active against Gram-positive and Gram-negative bacteria, and were tested against mastitis isolates from dairy cows. METHODS AND RESULTS: Two bioassays were adapted for Xenorhabdus antibiotics; an overlay method on agar plates, and serially diluted, cell-free, Xenorhabdus cultures. The antimicrobial activities of the liquid cultures of 13 strains from five Xenorhabdus species were further evaluated. Antimicrobial activities of the type strains of X. nematophila, X. budapestensis and X. szentirmaii were tested on mastitis isolates of Staphylococcus aureus, Escherichia coli and Klebsiella pneumoniae with both bioassays. A previously reported antibiotic from X. nematophila, nematophin, was synthesized in three steps from tryptamine and 4-methyl-2-oxovaleric acid sodium salt. CONCLUSIONS: The antibiotics of all three Xenorhabdus strains were powerful in either bioassay, but the sensitivity of the isolates differed from each other. While Kl. pneumoniae was the least susceptible, Staph. aureus had the highest sensitivity to each Xenorhabdus strain. Xenorhabdus szentirmaii and X. budapestensis were more potent antibiotic producers than X. nematophila, and raceme nematophin was ineffective against all mastitis isolates. SIGNIFICANCE AND IMPACT OF THE STUDY: These results indicate that Xenorhabdus antibiotics are effective against mastitis isolates and should be further evaluated for their potential in mastitis control or prevention.

Isolation and characterization of a Geobacillus thermoleovorans strain from an ultra-deep South African gold mine.

A thermophilic facultative bacterial isolate was recovered from 3.2km depth in a gold mine in South Africa. This isolate, designated GE-7, was cultivated from pH 8.0, 50 degrees C water from a dripping fracture near the top of an exploration tunnel. GE-7 grows optimally at 65 degrees C and pH 6.5 on a wide range of carbon substrates including cellobiose, hydrocarbons and lactate. In addition to O(2), GE-7 also utilizes nitrate as an electron acceptor. GE-7 is a long rod-shaped bacterium (4-6microm longx0.5microm wide) with terminal endospores and flagella. Phylogenetic analysis of GE-7 16S rDNA sequence revealed high sequence similarity with G. thermoleovorans DSM 5366(T) (99.6%), however, certain phenotypic characteristics of GE-7 were distinct from this and other previously described strains of G. thermoleovorans.

Desulfurobacterium atlanticum sp. nov., Desulfurobacterium pacificum sp. nov. and Thermovibrio guaymasensis sp. nov., three thermophilic members of the Desulfurobacteriaceae fam. nov., a deep branching lineage within the Bacteria.

Three thermophilic, anaerobic, strictly chemolithoautotrophic, sulphur- and/or thiosulphate-reducing bacteria, designated SL17(T), SL19(T) and SL22(T), were isolated from deep-sea hydrothermal samples collected at 13 degrees N (East Pacific Rise), Guaymas Basin (Gulf of California) and 23 degrees N (Mid-Atlantic Ridge), respectively. These strains differed in their morphology, temperature range and optimum for growth, energy substrates and 16S rRNA gene sequences. The G+C content of the genomic DNA was 41 mol% (SL22(T)), 42 mol% (SL17(T)) and 46 mol% (SL19(T)). Comparative analysis of phenotypic and phylogenetic traits indicated that strains SL17(T) and SL22(T) represented two novel species of the genus Desulfurobacterium and that strain SL19(T) should be considered as a novel species of the genus Thermovibrio. The names Desulfurobacterium pacificum sp. nov. (type strain SL17(T)=DSM 15522(T)=JCM 12127(T)), Desulfurobacterium atlanticum sp. nov. (type strain SL22(T)=DSM 15668(T)=JCM 12129(T)) and Thermovibrio guaymasensis sp. nov. (type strain SL19(T)=DSM 15521(T)=JCM 12128(T)) are proposed for these organisms. Furthermore, phylogenetic data based on 16S rRNA gene sequence analyses correlated with the significant phenotypic differences between members of the lineage encompassing the genera Desulfurobacterium, Thermovibrio and Balnearium and that of the families Aquificaceae and Hydrogenothermaceae. It is therefore proposed that this lineage represents a new family, Desulfurobacteriaceae fam. nov., within the order Aquificales.

A method for extracting RNA from dormant and germinating Bacillus subtilis strain 168 endospores.

RNA was extracted from dormant and germinating Bacillus subtilis 168 spores (intact spores and chemically decoated spores) by using rapid rupture followed by acid-phenol extraction. Spore germination progress was monitored by assaying colony forming ability before and after heat shock and by reading the optical density at 600 nm. The purity, yield, and composition of the extracted RNA were determined spectrophotometrically from the ratio of absorption at 260 nm to that at 280 nm; in a 2100 BioAnalyzer, giving the RNA yield/10(8) spores or cells and the distribution pattern of rRNA components. The method reported here for the extraction of RNA from dormant spores, as well as during different phases of germination and outgrowth, has proven to be fast, efficient and simple to handle. RNA of a high purity was obtained from dormant spores and during all phases of germination and growth. There was a significant increase in RNA yield during the transition from dormant spores to germination and subsequent outgrowth. Chemically decoated spores were retarded in germination and outgrowth compared with intact spores, and less RNA was extracted; however, the differences were not significant. This method for RNA isolation of dormant, germinating, and outgrowing bacterial endospores is a valuable prerequisite for gene expression studies, especially in studies on the responses of spores to hostile environmental conditions.

Vulcanibacillus modesticaldus gen. nov., sp. nov., a strictly anaerobic, nitrate-reducing bacterium from deep-sea hydrothermal vents.

A novel anaerobic, moderately thermophilic, spore-forming bacterium, designated strain BRT, was isolated from deep-sea hydrothermal core samples collected at the Rainbow vent field on the Mid-Atlantic Ridge (36 degrees 14' N 33 degrees 54' W). The cells were found to be rod-shaped, non-motile, Gram-positive and spore-forming. The organism grew in the temperature range 37-60 degrees C, with an optimum at 55 degrees C, and at pH values in the range 6-8.5, with an optimum around pH 7. NaCl concentrations for growth were in the range 10-40 g l(-1), with an optimum at 20-30 g l(-1). Strain BRT grew chemo-organoheterotrophically with carbohydrates, proteinaceous substrates and organic acids with nitrate as electron acceptor. The novel isolate was not able to ferment. The G+C content of the genomic DNA was 34.5 mol%. Phylogenetic analysis of the 16S rRNA gene sequence placed strain BRT in the Bacillaceae within the class 'Bacilli'. On the basis of the phenotypic and phylogenetic data, this isolate should be described as a member of a novel genus, for which the name Vulcanibacillus gen. nov. is proposed. The type species is Vulcanibacillus modesticaldus sp. nov., with the type strain BRT (=DSM 14931T=JCM 12998T).

Occurrence and characterization of actinobacteria and thermoactinomycetes isolated from pulp and board samples containing recycled fibres.

The aim of this study was to characterize the actinobacterial population present in pulps and boards containing recycled fibres. A total of 107 isolates was identified on the basis of their pigmentation, morphological properties, fatty acid profiles and growth temperature. Of the wet pulp and water sample isolates (n=87), 74.7% belonged to the genus Streptomyces, 17.2% to Nocardiopsis and 8.0% to thermoactinomycetes, whereas all the board sample isolates (n=20) were thermoactinomycetes. The identification of 53 isolates was continued by molecular methods. Partial 16S rDNA sequencing and automated ribotyping divided the Streptomyces isolates (n=31) into 14 different taxa. The most common streptomycetes were the mesophilic S. albidoflavus and moderately thermophilic S. thermocarboxydus. The Nocardiopsis isolates (n=11) belonged to six different taxa, whereas the thermoactinomycetes were mainly members of the species Laceyella sacchari (formerly Thermoactinomyces sacchari). The results indicated the probable presence of one or more new species within each of these genera. Obviously, the drying stage used in the board making processes had eliminated all members of the species Streptomyces and Nocardiopsis present in the wet recycled fibre pulp samples. Only the thermotolerant endospores of L. sacchari were still present in the final products. The potential of automated ribotyping for identifying actinobacteria was indicated, as soon as comprehensive identification libraries became available.

Mycobacterium fluoranthenivorans sp. nov., a fluoranthene and aflatoxin B1 degrading bacterium from contaminated soil of a former coal gas plant.

Mycobacterium strain FA4T was isolated with fluoranthene as the single carbon source from soil of a former coal gas plant, polluted with polycyclic aromatic hydrocarbons. The physiological properties, fatty acid pattern, and the 16S ribosomal RNA gene sequence indicated membership to the genus Mycobacterium, but were different from all type strains of Mycobacterium species. Based on comparative 16S rRNA gene sequence analyses strain FA4T could be assigned to the Mycobacterium neoaurum taxon showing 98% sequence similarity to M. diernhoferi as its closest neighbour. The occurrence of epoxymycolate in the cell wall differentiates FA4 from all members of this taxon which synthesize wax-ester mycolates in addition to alpha-mycolates. Strain FA4T is able to degrade aflatoxin B1. This biological attribute might be useful in biological detoxification processes of foods and feeds. From the investigated characteristics it is concluded that strain FA4T represents a new species, for which we propose the name Mycobacterium fluoranthenivorans sp. nov. The type strain of Mycobacterium fluoranthenivorans is FA4T (DSM 44556T = CIP 108203T).

Culture-independent analysis of bacterial species from an anaerobic mat from Lake Fryxell, Antarctica: prokaryotic diversity revisited.

Using a lake sediment mat sample from Lake Fryxell, Antarctica, different DNA extraction and purification methods were compared by denaturing gradient gel electrophoresis (DGGE). Based on the analyses of cloned 16S rRNA gene sequences a high degree of as yet uncultured prokaryotes have been reported in this sample. Although the vast majority of these as yet uncultured organisms seem to be classified as representatives of Firmicutes, Proteobacteria and Bacteriodetes, many of these taxa should be regarded novel species as judged from the distance of their gene sequences to those of their nearest cultured phylogenetic neighbours. The physiological properties of cultured strains from Lake Fryxell and of those of described species that are phylogenetically affiliated to the as yet uncultured species from this environment, suggest the presence of a well developed food web of primary producers, anaerobic degraders and fermenters, and aerobes. The few novel species described from this sample add to the increasing number of species characterized from various Antarctic habitats. Determination of the phylogenetic relatedness of the mat clone sequences of Clostridia with recent entries into public databases revealed that many of the putative species are closely related to other putative species detected in a broad range of environments, ranging from rumen and gut, anaerobic and polluted soil to sediment and groundwater samples.

Caminibacter profundus sp. nov., a novel thermophile of Nautiliales ord. nov. within the class 'Epsilonproteobacteria', isolated from a deep-sea hydrothermal vent.

A novel moderately thermophilic, microaerobic to anaerobic, chemolithoautotrophic bacterium, designated strain CRT, was isolated from a deep-sea hydrothermal vent site at 36 degrees N on the Mid-Atlantic Ridge. Cells were Gram-negative, non-motile rods. The organism grew at 45-65 degrees C and pH 6.5-7.4, with optimum growth at 55 degrees C and pH 6.9-7.1. The NaCl range for growth was 5-50 g l(-1) (optimum 30 g l(-1)). Strain CRT was an obligate chemolithoautotroph, growing with H2 as energy source, sulfur, nitrate or oxygen as electron acceptors and CO2 as carbon source. Hydrogen sulfide and ammonium were the respective products of sulfur and nitrate reduction. The G+C content of the genomic DNA was 32.1 mol%. Based on 16S rRNA gene sequence analysis, this organism was most closely related to Caminibacter hydrogeniphilus (94.9% similarity). On the basis of phenotypic and phylogenetic data, it is proposed that the isolate represents a novel species, Caminibacter profundus sp. nov. The type strain is CRT (=DSM 15016T=JCM 11957T). The phylogenetic data also correlate well with the significant phenotypic differences between the lineage encompassing the genera Nautilia and Caminibacter and other members of the class 'Epsilonproteobacteria'. The lineage encompassing the genera Nautilia and Caminibacter is therefore proposed as a new order, Nautiliales ord. nov., represented by a single family, Nautiliaceae fam. nov.

Thermodesulfatator indicus gen. nov., sp. nov., a novel thermophilic chemolithoautotrophic sulfate-reducing bacterium isolated from the Central Indian Ridge.

A thermophilic, marine, anaerobic, chemolithoautotrophic, sulfate-reducing bacterium, strain CIR29812T, was isolated from a deep-sea hydrothermal vent site at the Kairei vent field on the Central Indian Ridge. Cells were Gram-negative motile rods that did not form spores. The temperature range for growth was 55-80 degrees C, with an optimum at 70 degrees C. The NaCl concentration range for growth was 10-35 g l(-1), with an optimum at 25 g l(-1). The pH range for growth was 6-6.7, with an optimum at approximately pH 6.25. H2 and CO2 were the only electron donor and carbon source found to support growth of the strain. However, several organic compounds were stimulatory for growth. Sulfate was used as electron acceptor, whereas elemental sulfur, thiosulfate, sulfite, cystine, nitrate and fumarate were not. No fermentative growth was observed with malate, pyruvate or lactate. The phenotypic characteristics of strain CIR29812T were similar to those of Thermodesulfobacterium hydrogeniphilum, a recently described thermophilic, chemolithoautotrophic sulfate-reducer. However, phylogenetic analyses of the 16S rRNA gene sequences showed that the new isolate was distantly related to members of the family Thermodesulfobacteriaceae (similarity values of less than 90%). The chemotaxonomic data (fatty acids and polar lipids composition) also indicated that strain CIR29812T could be distinguished from Thermodesulfobacterium commune, the type species of the type genus of the family Thermodesulfobacteriaceae. Finally, the G+C content of the genomic DNA of strain CIR29812T (46.0 mol%) was not in the range of values obtained for members of this family. On the basis of phenotypic, chemotaxonomic and genomic features, it is proposed that strain CIR29812T represents a novel species of a new genus, Thermodesulfatator, of which Thermodesulfatator indicus is the type species. The type strain is CIR29812T (=DSM 15286T=JCM 11887T).