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Anna-louise Reysenbach - One of the best experts on this subject based on the ideXlab platform.
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sulfurihydrogenibium azorense sp nov a thermophilic hydrogen oxidizing Microaerophile from terrestrial hot springs in the azores
International Journal of Systematic and Evolutionary Microbiology, 2004Co-Authors: Paula Aguiar, T J Beveridge, Anna-louise ReysenbachAbstract:Five hydrogen-oxidizing, thermophilic, strictly chemolithoautotrophic, microaerophilic strains, with similar (99–100 %) 16S rRNA gene sequences were isolated from terrestrial hot springs at Furnas, Sao Miguel Island, Azores, Portugal. The strain, designated Az-Fu1T, was characterized. The motile, 0·9–2·0 μm rods were Gram-negative and non-sporulating. The temperature growth range was from 50 to 73 °C (optimum at 68 °C). The strains grew fastest in 0·1 % (w/v) NaCl and at pH 6, although growth was observed from pH 5·5 to 7·0. Az-Fu1T can use elemental sulfur, sulfite, thiosulfate, ferrous iron or hydrogen as electron donors, and oxygen (0·2–9·0 %, v/v) as electron acceptor. Az-Fu1T is also able to grow anaerobically, with elemental sulfur, arsenate and ferric iron as electron acceptors. The Az-Fu1T G+C content was 33·6 mol%. Maximum-likelihood analysis of the 16S rRNA phylogeny placed the isolate in a distinct lineage within the Aquificales, closely related to Sulfurihydrogenibium subterraneum (2·0 % distant). The 16S rRNA gene of Az-Fu1T is 7·7 % different from that of Persephonella marina and 6·8 % different from Hydrogenothermus marinus. Based on the phenotypic and phylogenetic characteristics presented here, it is proposed that Az-Fu1T belongs to the recently described genus Sulfurihydrogenibium. It is further proposed that Az-Fu1T represents a new species, Sulfurihydrogenibium azorense.
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sulfurihydrogenibium azorense sp nov a thermophilic hydrogen oxidizing Microaerophile from terrestrial hot springs in the azores
International Journal of Systematic and Evolutionary Microbiology, 2004Co-Authors: Paula Aguiar, T J Beveridge, Anna-louise ReysenbachAbstract:Five hydrogen-oxidizing, thermophilic, strictly chemolithoautotrophic, microaerophilic strains, with similar (99-100%) 16S rRNA gene sequences were isolated from terrestrial hot springs at Furnas, Sao Miguel Island, Azores, Portugal. The strain, designated Az-Fu1T, was characterized. The motile, 0.9-2.0 microm rods were Gram-negative and non-sporulating. The temperature growth range was from 50 to 73 degrees C (optimum at 68 degrees C). The strains grew fastest in 0.1% (w/v) NaCl and at pH 6, although growth was observed from pH 5.5 to 7.0. Az-Fu1T can use elemental sulfur, sulfite, thiosulfate, ferrous iron or hydrogen as electron donors, and oxygen (0.2-9.0%, v/v) as electron acceptor. Az-Fu1T is also able to grow anaerobically, with elemental sulfur, arsenate and ferric iron as electron acceptors. The Az-Fu1T G+C content was 33.6 mol%. Maximum-likelihood analysis of the 16S rRNA phylogeny placed the isolate in a distinct lineage within the Aquificales, closely related to Sulfurihydrogenibium subterraneum (2.0% distant). The 16S rRNA gene of Az-Fu1T is 7.7% different from that of Persephonella marina and 6.8% different from Hydrogenothermus marinus. Based on the phenotypic and phylogenetic characteristics presented here, it is proposed that Az-Fu1T belongs to the recently described genus Sulfurihydrogenibium. It is further proposed that Az-Fu1T represents a new species, Sulfurihydrogenibium azorense.
Robert K Poole - One of the best experts on this subject based on the ideXlab platform.
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transcriptome and proteome dynamics in chemostat culture reveal how campylobacter jejuni modulates metabolism stress responses and virulence factors upon changes in oxygen availability
Environmental Microbiology, 2017Co-Authors: Edward Guccione, Robert K Poole, John J Kendall, Andrew Hitchcock, Nitanshu Garg, Michael A White, Francis Mulholland, David J KellyAbstract:Campylobacter jejuni, the most frequent cause of food-borne bacterial gastroenteritis worldwide, is a Microaerophile that has to survive high environmental oxygen tensions, adapt to oxygen limitation in the intestine and resist host oxidative attack. Here, oxygen-dependent changes in C. jejuni physiology were studied at constant growth rate using carbon (serine)-limited continuous chemostat cultures. We show that a perceived aerobiosis scale can be calibrated by the acetate excretion flux, which becomes zero when metabolism is fully aerobic (100% aerobiosis). Transcriptome changes in a downshift experiment from 150% to 40% aerobiosis revealed many novel oxygen-regulated genes and highlighted re-modelling of the electron transport chains. A label-free proteomic analysis showed that at 40% aerobiosis, many proteins involved in host colonisation (e.g., PorA, CadF, FlpA, CjkT) became more abundant. PorA abundance increased steeply below 100% aerobiosis. In contrast, several citric-acid cycle enzymes, the peptide transporter CstA, PEB1 aspartate/glutamate transporter, LutABC lactate dehydrogenase and PutA proline dehydrogenase became more abundant with increasing aerobiosis. We also observed a co-ordinated response of oxidative stress protection enzymes and Fe-S cluster biogenesis proteins above 100% aerobiosis. Our approaches reveal key virulence factors that respond to restricted oxygen availability and specific transporters and catabolic pathways activated with increasing aerobiosis.
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oxygen reactivity of both respiratory oxidases in campylobacter jejuni the cydab genes encode a cyanide resistant low affinity oxidase that is not of the cytochrome bd type
Journal of Bacteriology, 2007Co-Authors: R Jackson, Laura M Wainwright, Simon F Park, Karen T Elvers, Mark D Gidley, James Lightfoot, Robert K PooleAbstract:Campylobacter jejuni is the predominant bacterial agent of human gastrointestinal infections worldwide and therefore represents a major global public health burden (15). Currently, the development of health protection interventions against this food-borne pathogen is restricted by our limited knowledge of the mechanisms that confer virulence and enable the pathogen to persist within the food chain. The major reservoir for campylobacters is broiler flocks of poultry reared for human consumption. The predominant clinical feature of campylobacteriosis is the development of acute enteritis, abdominal pain, and diarrhea. Uncommon but serious complications may, however, ensue (27). Members of the genus Campylobacter are gram-negative, highly motile, flagellate, spirally curved rods. A distinguishing feature is their strictly microaerophilic lifestyle (16), requiring an atmospheric composition of 5 to 10% oxygen and 5 to 13% carbon dioxide for optimal growth, but oxygen metabolism and the basis of microaerophily are poorly understood. Hydrogen and formate are the most effective sources of energy for C. jejuni (18). NADH dehydrogenase activity in C. jejuni is low, and NADPH acts as a more effective electron donor than NADH in campylobacters (18, 24). The predominant quinone species is dimethylmenaquinone-6 (26). Campylobacters are very rich in b- and c-type cytochromes, but most of these are uncharacterized. The lack of any spectrophotometric signals in the red spectral region suggests that campylobacters lack cytochromes of the a and d types (18, 24, 29), but several lines of evidence point to terminally branched respiratory pathways. First, during aerobic formate oxidation, two systems appeared to operate in Campylobacter sputorum subsp. bubulus (30): one was linked to the respiratory chain and thought to be responsible for proton translocation, and the other was of lower O2 affinity and tentatively described as a H2O2-producing system. Second, cyanide sensitivity studies indicated that the respiratory chain is branched, terminating at two oxidases that differ in their sensitivities to cyanide (18, 24), but the oxidases have not been identified at the molecular level or further characterized. These early biochemical and physiological studies have been complemented by analysis of the genome sequence of C. jejuni NCTC11168, which is predicted to encode components of an aerobic respiratory chain, namely, dehydrogenases (including a putative NADH:quinone reductase, NDH-1), a cytochrome bc1 complex, and two terminal oxidases (31, 45). Other genes encoding respiratory components include genes for c-type cytochromes (Cj0037c, Cj0874c, Cj1020c, Cj1153, Cj1357c, and Cj1358c) and for a putative ubiquinol-cytochrome c reductase (Cj1184-6c) (31). Although the existence of cytochrome o in succinate-reduced extracts and membranes of Campylobacter fetus has been reported (24), the genome sequence does not reveal genes likely to encode such an oxidase. The genome also contains genes for two periplasmic cytochrome c peroxidases, namely, Cj0020c and Cj0358 (31). Genes annotated as encoding a “cytochrome bd oxidase” are present (Cj0081-2), in addition to genes coding for a putative “cb-type cytochrome c oxidase” or “cytochrome cbb3-type oxidase” (Cj1487c, Cj1488c, Cj1489c, and Cj1490c) (31, 45). In this paper, we describe a detailed study of the oxygen reactivity of C. jejuni and assign distinct oxygen affinities and cyanide sensitivities to the two oxidases. Such studies contribute to an understanding of the microaerophilic lifestyle of this important human pathogen.
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purification and spectroscopic characterization of ctb a group iii truncated hemoglobin implicated in oxygen metabolism in the food borne pathogen campylobacter jejuni
Biochemistry, 2006Co-Authors: Laura M Wainwright, Syun Ru Yeh, Yinghua Wang, Simon F Park, Robert K PooleAbstract:Campylobacter jejuni is a food-borne bacterial pathogen that possesses two distinct hemoglobins, encoded by the ctb and cgb genes. The former codes for a truncated hemoglobin (Ctb) in group III, an assemblage of uncharacterized globins in diverse clinically and technologically significant bacteria. Here, we show that Ctb purifies as a monomeric, predominantly oxygenated species. Optical spectra of ferric, ferrous, O(2)- and CO-bound forms resemble those of other hemoglobins. However, resonance Raman analysis shows Ctb to have an atypical nu(Fe)(-)(CO) stretching mode at 514 cm(-)(1), compared to those of the other truncated hemoglobins that have been characterized so far. This implies unique roles in ligand stabilization for TyrB10, HisE7, and TrpG8, residues highly conserved within group III truncated hemoglobins. Because C. jejuni is a Microaerophile, and a ctb mutant exhibits O(2)-dependent growth defects, one of the hypothesized roles of Ctb is in the detoxification, sequestration, or transfer of O(2). The midpoint potential (E(h)) of Ctb was found to be -33 mV, but no evidence was obtained in vitro to support the hypothesis that Ctb is reducible by NADH or NADPH. This truncated hemoglobin may function in the facilitation of O(2) transfer to one of the terminal oxidases of C. jejuni or, instead, facilitate O(2) transfer to Cgb for NO detoxification.
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microaerobic physiology aerobic respiration anaerobic respiration and carbon dioxide metabolism
2001Co-Authors: David J Kelly, Nicky J Hughes, Robert K PooleAbstract:In aerobic respiration, electron transfer is to oxygen (more correctly, the dioxygen molecule), which is reduced to water with concomitant, coupled ion translocation and generation of an electrochemical gradient. In anaerobic respiration, electron transfer is to a molecule other than oxygen or to an ionic species, again coupled to generation of an electrochemical gradient. This chapter is concerned primarily with substrate oxidations and the use of oxygen as electron acceptor. It examines the evidence for facultative respiration in Helicobacter pylori and considers the extent to which the respiratory pathways of this bacterium can be gleaned from the somewhat limited biochemical evidence presently available, and from comparisons with mitochondrial and bacterial paradigms. Oxidative stress responses are coordinated by a number of global regulatory proteins. In H. pylori, alkylhydroperoxide reductase, catalase, and superoxide dismutase have been particularly implicated in the enzymatic destruction of toxic oxidants and are discussed in the chapter. H. pylori is generally regarded as a Microaerophile, but the bacterium also requires an elevated level of atmospheric CO2 for optimal growth.
David J Kelly - One of the best experts on this subject based on the ideXlab platform.
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Genes Linking Copper Trafficking and Homeostasis to the Biogenesis and Activity of the cbb3-Type Cytochrome c Oxidase in the Enteric Pathogen Campylobacter jejuni
'Frontiers Media SA', 2021Co-Authors: Nitanshu Garg, Aidan J Taylor, Federica Pastorelli, Sarah E. Flannery, Phillip J. Jackson, Matthew P. Johnson, David J KellyAbstract:Bacterial C-type haem-copper oxidases in the cbb3 family are widespread in Microaerophiles, which exploit their high oxygen-binding affinity for growth in microoxic niches. In microaerophilic pathogens, C-type oxidases can be essential for infection, yet little is known about their biogenesis compared to model bacteria. Here, we have identified genes involved in cbb3-oxidase (Cco) assembly and activity in the Gram-negative pathogen Campylobacter jejuni, the commonest cause of human food-borne bacterial gastroenteritis. Several genes of unknown function downstream of the oxidase structural genes ccoNOQP were shown to be essential (cj1483c and cj1486c) or important (cj1484c and cj1485c) for Cco activity; Cj1483 is a CcoH homologue, but Cj1484 (designated CcoZ) has structural similarity to MSMEG_4692, involved in Qcr-oxidase supercomplex formation in Mycobacterium smegmatis. Blue-native polyacrylamide gel electrophoresis of detergent solubilised membranes revealed three major bands, one of which contained CcoZ along with Qcr and oxidase subunits. Deletion of putative copper trafficking genes ccoI (cj1155c) and ccoS (cj1154c) abolished Cco activity, which was partially restored by addition of copper during growth, while inactivation of cj0369c encoding a CcoG homologue led to a partial reduction in Cco activity. Deletion of an operon encoding PCuAC (Cj0909) and Sco (Cj0911) periplasmic copper chaperone homologues reduced Cco activity, which was partially restored in the cj0911 mutant by exogenous copper. Phenotypic analyses of gene deletions in the cj1161c–1166c cluster, encoding several genes involved in intracellular metal homeostasis, showed that inactivation of copA (cj1161c), or copZ (cj1162c) led to both elevated intracellular Cu and reduced Cco activity, effects exacerbated at high external Cu. Our work has therefore identified (i) additional Cco subunits, (ii) a previously uncharacterized set of genes linking copper trafficking and Cco activity, and (iii) connections with Cu homeostasis in this important pathogen
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the function biogenesis and regulation of the electron transport chains in campylobacter jejuni new insights into the bioenergetics of a major food borne pathogen
Advances in Microbial Physiology, 2019Co-Authors: Aidan J Taylor, David J KellyAbstract:Abstract Campylobacter jejuni is a zoonotic Epsilonproteobacterium that grows in the gastrointestinal tract of birds and mammals, and is the most frequent cause of food-borne bacterial gastroenteritis worldwide. As an oxygen-sensitive Microaerophile, C. jejuni has to survive high environmental oxygen tensions, adapt to oxygen limitation in the host intestine and resist host oxidative attack. Despite its small genome size, C. jejuni is a versatile and metabolically active pathogen, with a complex and highly branched set of respiratory chains allowing the use of a wide range of electron donors and alternative electron acceptors in addition to oxygen, including fumarate, nitrate, nitrite, tetrathionate and N- or S-oxides. Several novel enzymes participate in these electron transport chains, including a tungsten containing formate dehydrogenase, a Complex I that uses flavodoxin and not NADH, a periplasmic facing fumarate reductase and a cytochrome c tetrathionate reductase. This review presents an updated description of the composition and bioenergetics of these various respiratory chains as they are currently understood, including recent work that gives new insights into energy conservation during electron transport to various alternative electron acceptors. The regulation of synthesis and assembly of the electron transport chains is also discussed. A deeper appreciation of the unique features of the respiratory systems of C. jejuni may be helpful in informing strategies to control this important pathogen.
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transcriptome and proteome dynamics in chemostat culture reveal how campylobacter jejuni modulates metabolism stress responses and virulence factors upon changes in oxygen availability
Environmental Microbiology, 2017Co-Authors: Edward Guccione, Robert K Poole, John J Kendall, Andrew Hitchcock, Nitanshu Garg, Michael A White, Francis Mulholland, David J KellyAbstract:Campylobacter jejuni, the most frequent cause of food-borne bacterial gastroenteritis worldwide, is a Microaerophile that has to survive high environmental oxygen tensions, adapt to oxygen limitation in the intestine and resist host oxidative attack. Here, oxygen-dependent changes in C. jejuni physiology were studied at constant growth rate using carbon (serine)-limited continuous chemostat cultures. We show that a perceived aerobiosis scale can be calibrated by the acetate excretion flux, which becomes zero when metabolism is fully aerobic (100% aerobiosis). Transcriptome changes in a downshift experiment from 150% to 40% aerobiosis revealed many novel oxygen-regulated genes and highlighted re-modelling of the electron transport chains. A label-free proteomic analysis showed that at 40% aerobiosis, many proteins involved in host colonisation (e.g., PorA, CadF, FlpA, CjkT) became more abundant. PorA abundance increased steeply below 100% aerobiosis. In contrast, several citric-acid cycle enzymes, the peptide transporter CstA, PEB1 aspartate/glutamate transporter, LutABC lactate dehydrogenase and PutA proline dehydrogenase became more abundant with increasing aerobiosis. We also observed a co-ordinated response of oxidative stress protection enzymes and Fe-S cluster biogenesis proteins above 100% aerobiosis. Our approaches reveal key virulence factors that respond to restricted oxygen availability and specific transporters and catabolic pathways activated with increasing aerobiosis.
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microaerobic physiology aerobic respiration anaerobic respiration and carbon dioxide metabolism
2001Co-Authors: David J Kelly, Nicky J Hughes, Robert K PooleAbstract:In aerobic respiration, electron transfer is to oxygen (more correctly, the dioxygen molecule), which is reduced to water with concomitant, coupled ion translocation and generation of an electrochemical gradient. In anaerobic respiration, electron transfer is to a molecule other than oxygen or to an ionic species, again coupled to generation of an electrochemical gradient. This chapter is concerned primarily with substrate oxidations and the use of oxygen as electron acceptor. It examines the evidence for facultative respiration in Helicobacter pylori and considers the extent to which the respiratory pathways of this bacterium can be gleaned from the somewhat limited biochemical evidence presently available, and from comparisons with mitochondrial and bacterial paradigms. Oxidative stress responses are coordinated by a number of global regulatory proteins. In H. pylori, alkylhydroperoxide reductase, catalase, and superoxide dismutase have been particularly implicated in the enzymatic destruction of toxic oxidants and are discussed in the chapter. H. pylori is generally regarded as a Microaerophile, but the bacterium also requires an elevated level of atmospheric CO2 for optimal growth.
John A Breznak - One of the best experts on this subject based on the ideXlab platform.
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physiological ecology of stenoxybacter acetivorans an obligate Microaerophile in termite guts
Applied and Environmental Microbiology, 2007Co-Authors: John T Wertz, John A BreznakAbstract:Stenoxybacter acetivorans is a newly described, obligately microaerophilic beta-proteobacterium that is abundant in the acetate-rich hindgut of Reticulitermes. Here we tested the hypotheses that cells are located in the hypoxic, peripheral region of Reticulitermes flavipes hindguts and use acetate to fuel their O(2)-consuming respiratory activity in situ. Physical fractionation of R. flavipes guts, followed by limited-cycle PCR with S. acetivorans-specific 16S rRNA gene primers, indicated that cells of this organism were indeed located primarily among the microbiota colonizing the hindgut wall. Likewise, reverse transcriptase PCR of hindgut RNA revealed S. acetivorans-specific transcripts for acetate-activating enzymes that were also found in cell extracts (acetate kinase and phosphotransacetylase), as well as transcripts of ccoN, which encodes the O(2)-reducing subunit of high-affinity cbb(3)-type cytochrome oxidases. However, S. acetivorans strains did not possess typical enzymes of the glyoxylate cycle (isocitrate lyase and malate synthase A), suggesting that they may use an alternate pathway to replenish tricarboxylic acid cycle intermediates or they obtain such compounds (or their precursors) in situ. Respirometric measurements indicated that much of the O(2) consumption by R. flavipes worker larvae was attributable to their guts, and the potential contribution of S. acetivorans to O(2) consumption by extracted guts was about 0.2%, a value similar to that obtained for other hindgut bacteria examined. Similar measurements obtained with guts of larvae prefed diets to disrupt major members of the hindgut microbiota implied that most of the O(2) consumption observed with extracted guts was attributable to protozoans, a group of microbes long thought to be "strict anaerobes."
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stenoxybacter acetivorans gen nov sp nov an acetate oxidizing obligate Microaerophile among diverse o2 consuming bacteria from termite guts
Applied and Environmental Microbiology, 2007Co-Authors: John T Wertz, John A BreznakAbstract:In termite hindguts, fermentative production of acetate--a major carbon and energy source for the insect--depends on efficient removal of inwardly diffusing oxygen by microbes residing on and near the hindgut wall. However, little is known about the identity of these organisms or about the substrate(s) used to support their respiratory activity. A cultivation-based approach was used to isolate O(2)-consuming organisms from hindguts of Reticulitermes flavipes. A consistently greater (albeit not statistically significant) number of colonies developed under hypoxia (2% [vol/vol] O(2)) than under air, and the increase coincided with the appearance of morphologically distinct colonies of a novel, rod-shaped, obligately microaerophilic beta-proteobacterium that was <95% similar (based on the 16S rRNA gene sequence) to its closest known relative (Eikenella corrodens). Nearly identical organisms (and/or their 16S rRNA genes) were obtained from geographically separated and genetically distinct populations of Reticulitermes. PCR-based procedures implied that the novel isolates were autochthonous to the hindgut of R. flavipes and comprised ca. 2 to 7% of the hindgut prokaryote community. Representative strain TAM-DN1 utilized acetate and a limited range of other organic and amino acids as energy sources and possessed catalase and superoxide dismutase. On solid medium, the optimal O(2) concentration for growth was about 2%, and no growth occurred with O(2) concentrations above 4% or under anoxia. However, cells in liquid medium could grow with higher O(2) concentrations (up to 16%), but only after proportionately extended lag phases. The genetic and physiological distinctiveness of TAM-DN1 and related strains supports their recognition as a new genus and species, for which the name Stenoxybacter acetivorans gen. nov., sp. nov. is proposed.
Paula Aguiar - One of the best experts on this subject based on the ideXlab platform.
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sulfurihydrogenibium azorense sp nov a thermophilic hydrogen oxidizing Microaerophile from terrestrial hot springs in the azores
International Journal of Systematic and Evolutionary Microbiology, 2004Co-Authors: Paula Aguiar, T J Beveridge, Anna-louise ReysenbachAbstract:Five hydrogen-oxidizing, thermophilic, strictly chemolithoautotrophic, microaerophilic strains, with similar (99–100 %) 16S rRNA gene sequences were isolated from terrestrial hot springs at Furnas, Sao Miguel Island, Azores, Portugal. The strain, designated Az-Fu1T, was characterized. The motile, 0·9–2·0 μm rods were Gram-negative and non-sporulating. The temperature growth range was from 50 to 73 °C (optimum at 68 °C). The strains grew fastest in 0·1 % (w/v) NaCl and at pH 6, although growth was observed from pH 5·5 to 7·0. Az-Fu1T can use elemental sulfur, sulfite, thiosulfate, ferrous iron or hydrogen as electron donors, and oxygen (0·2–9·0 %, v/v) as electron acceptor. Az-Fu1T is also able to grow anaerobically, with elemental sulfur, arsenate and ferric iron as electron acceptors. The Az-Fu1T G+C content was 33·6 mol%. Maximum-likelihood analysis of the 16S rRNA phylogeny placed the isolate in a distinct lineage within the Aquificales, closely related to Sulfurihydrogenibium subterraneum (2·0 % distant). The 16S rRNA gene of Az-Fu1T is 7·7 % different from that of Persephonella marina and 6·8 % different from Hydrogenothermus marinus. Based on the phenotypic and phylogenetic characteristics presented here, it is proposed that Az-Fu1T belongs to the recently described genus Sulfurihydrogenibium. It is further proposed that Az-Fu1T represents a new species, Sulfurihydrogenibium azorense.
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sulfurihydrogenibium azorense sp nov a thermophilic hydrogen oxidizing Microaerophile from terrestrial hot springs in the azores
International Journal of Systematic and Evolutionary Microbiology, 2004Co-Authors: Paula Aguiar, T J Beveridge, Anna-louise ReysenbachAbstract:Five hydrogen-oxidizing, thermophilic, strictly chemolithoautotrophic, microaerophilic strains, with similar (99-100%) 16S rRNA gene sequences were isolated from terrestrial hot springs at Furnas, Sao Miguel Island, Azores, Portugal. The strain, designated Az-Fu1T, was characterized. The motile, 0.9-2.0 microm rods were Gram-negative and non-sporulating. The temperature growth range was from 50 to 73 degrees C (optimum at 68 degrees C). The strains grew fastest in 0.1% (w/v) NaCl and at pH 6, although growth was observed from pH 5.5 to 7.0. Az-Fu1T can use elemental sulfur, sulfite, thiosulfate, ferrous iron or hydrogen as electron donors, and oxygen (0.2-9.0%, v/v) as electron acceptor. Az-Fu1T is also able to grow anaerobically, with elemental sulfur, arsenate and ferric iron as electron acceptors. The Az-Fu1T G+C content was 33.6 mol%. Maximum-likelihood analysis of the 16S rRNA phylogeny placed the isolate in a distinct lineage within the Aquificales, closely related to Sulfurihydrogenibium subterraneum (2.0% distant). The 16S rRNA gene of Az-Fu1T is 7.7% different from that of Persephonella marina and 6.8% different from Hydrogenothermus marinus. Based on the phenotypic and phylogenetic characteristics presented here, it is proposed that Az-Fu1T belongs to the recently described genus Sulfurihydrogenibium. It is further proposed that Az-Fu1T represents a new species, Sulfurihydrogenibium azorense.
