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Robert E. Blankenship - One of the best experts on this subject based on the ideXlab platform.
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Structural Analysis of Alternative Complex III in the Photosynthetic Electron Transfer Chain of Chloroflexus aurantiacus
Biochemistry, 2010Co-Authors: Xinliu Gao, Yueyong Xin, Patrick D. Bell, Jianzhong Wen, Robert E. BlankenshipAbstract:Bacterial electron transport pathways largely fall into two major categories: the light-driven photosynthetic electron transfer chain and the aerobic or anaerobic respiratory electron transfer chain. Despite the vast differences between photo- and oxidative phosphorylations, they both couple the chemical reactions between electron donors and electron accepters to the translocation of protons across the membrane, which then drives ATP formation and other energy-dependent processes (1). As a result, the common feature of all electron transport chains is the presence of a proton pump to create the transmembrane proton gradient. In respiratory electron transfer pathways, there may be as many as three types of proton pumping protein complexes reminiscent of mitochondria, depending on environmental factors (2). In contrast, the proton pump in all the photosynthetic electron transfer chains was until recently believed to involve a cytochrome bc1 or b6f complex, which resemble mitochondrial complex III in terms of overall structure and mechanism (3). In the species tree of bacteria based on 16S rRNA analysis (4), the phylum of filamentous anoxygenic phototrophs (FAPs) is not closely related to the other phyla that contain organisms that carry out chlorophyll-based photosynthesis; purple bacteria, cyanobacteria, heliobacteria, green sulfur bacteria and chloroacidobacteria. Instead, it exhibits a much deeper branching position to the other five bacterial phyla that contain phototrophic representatives (5, 6). Because of this distinctive feature, the study of FAPs may shed an interesting light on the evolutionary development of photosynthesis. The FAPs are a very diverse and unique phylum of bacteria including several genera: Chloroflexus (7), Oscillochloris (8), Chloronema (9), Heliothrix (10) and several Chloroflexus-like bacteria found in marine environment (11). Among them, Chloroflexus aurantiacus, a prominent microorganism of hot spring microbial mat communities, was the first described and is the most extensively studied representative of FAPs in terms of its photosynthetic and other metabolic pathways. The photosynthetic apparatus of Chloroflexus aurantiacus exhibits an interesting combination of characteristics found in very different and diverse groups of phototrophic prokaryotes. They have a type II photoreaction center and integral membrane antenna complex reminiscent of purple bacteria (12, 13). In addition, they have a peripheral chlorosome antenna complex (14) and a chlorophyll biosynthesis pathway that are both similar to those found in green sulfur bacteria (15, 16). Chloroflexus aurantiacus also contains a unique autotrophic carbon fixation pathway different from that found in any other phototrophs, the 3-hydroxypropinate cycle (17, 18). Therefore, the phylogenetic characterization and the versatile photosynthetic apparatus of Chloroflexus aurantiacus suggest that it occupies an important place in the origin and evolution of photosynthesis (19). An intriguing characteristic of Chloroflexus aurantiacus is its extraordinary electron transfer pathway. For all types of photosynthetic organisms, following the initial process where the light energy transforms into chemical energy, the electrons pass through a series of electron carriers and ultimately either return to the electron donor side of the photosystem via a cyclic electron transfer pathway, or reduce a terminal electron acceptor in a non-cyclic electron transfer process (1). The overall pattern of electron transfer depends critically on the type of the organism, the environment it occupies, whether aerobic or anaerobic metabolism takes place and what type of terminal oxidants and reductants are present. While the electron transfer pathways appear to be quite different in various groups of phototrophs, one component was until recently believed to be a constant constituent in all photosynthetic system: the cytochrome bc1 or b6f complex, which transfers electrons from quinol to soluble cytochrome c or plastocyanin and at the same time translocates protons across the membrane, creating a transmembrane proton motive force (20, 21). However, Chloroflexus aurantiacus, like other members of the FAP phylum, does not exhibit either biochemical or genomic evidence for the existence of a related cytochrome bc1 or b6f complex. The lack of a cytochrome bc1 or b6f complex suggests that this group of organisms contains an unusual photosynthetic electron transfer pathway. A multi-subunit protein complex containing c-type cytochromes but no characteristic features of a cytochrome bc1 complex was isolated from C. aurantiacus by Yanyushin (22). A similar complex from Rhodothermus marinus is now named alternative complex III (ACIII) (23, 24). These two complexes have been proposed to be the functional substitute of the cytochrome bc1 complex based on gene analysis of sequenced genomes of various species (25) and an enzymatic study of ACIII from R. marinus (23). Recent enzyme kinetic analysis showing that ACIII performs the function of a quinol:auracyanin oxidoreductase strongly supports the hypothesis that ACIII fulfills the functional role of cytochrome bc1 complex in the photosynthetic electron transfer chain in Chloroflexus aurantiacus (26). Figure 1 shows the proposed cyclic electron transfer pathway in Chloroflexus aurantiacus. Figure 1 The proposed photosynthetic cyclic electron transfer pathway in Chloroflexus aurantiacus. Based on the genome arrangement of ACIII genes and early fundamental structural studies, the organization of ACIII was revealed to be entirely different from that of cytochrome bc1 or b6f complexes. However, a challenging question emerges - how does ACIII, a complex with structure vastly different from the cytochrome bc complex, carry out the same function in the electron transfer pathway in photosynthesis? A complete picture of the structure and role of ACIII complex is still missing. The key to elucidating this system is therefore believed to reside in understanding the ACIII complex in terms of its substructure and how this relates to its function in photosynthesis and respiration. In this work, a schematic structural model of the photosynthetic ACIII complex is proposed based on chemical cross-linking of subunits in tandem with MALDI-TOF mass spectrometry. The size and type of each subunit was determined by gel electrophoresis including one and two dimensional SDS-PAGE and native PAGE. The type and number of cofactors existing in the ACIII complex was investigated using metal analysis, HPLC combined with ESI-MS and potentiometric titrations.
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carotenoid and bacteriochlorophyll energy transfer in the b808 866 complex from Chloroflexus aurantiacus
Journal of Physical Chemistry B, 2004Co-Authors: Gabriel A. Montaño, Yueyong Xin, Su Lin, Robert E. BlankenshipAbstract:The B808−866 light-harvesting complex of the filamentous anoxygenic phototrophic green bacterium Chloroflexus aurantiacus has characteristics of both the LH1 and LH2 antenna complexes found in purp...
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Carotenoid and Bacteriochlorophyll Energy Transfer in the B808−866 Complex from Chloroflexus aurantiacus†
The Journal of Physical Chemistry B, 2004Co-Authors: Gabriel A. Montaño, Yueyong Xin, Su Lin, Robert E. BlankenshipAbstract:The B808−866 light-harvesting complex of the filamentous anoxygenic phototrophic green bacterium Chloroflexus aurantiacus has characteristics of both the LH1 and LH2 antenna complexes found in purp...
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The Protective Roles of the Antioxidant Enzymes Superoxide Dismutase and Catalase in the Green Photosynthetic Bacterium Chloroflexus Aurantiacus
2004Co-Authors: Robert E. Blankenship, Lynn RothschildAbstract:The purpose of this study was to examine the biochemical response of the green thermophilic photosynthetic bacterium Chloroflexus aurantiacus to oxidative stress. Lab experiments focused primarily on characterizing the antioxidant enzyme superoxide dismutase and the response of this organism to oxidative stress. Experiments in the field at the hotsprings in Yellowstone National Park focused on the changes in the level of these enzymes during the day in response to oxidants and to the different types of ultraviolet radiation.
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excitation delocalization in the bacteriochlorophyll c antenna of the green bacterium Chloroflexus aurantiacus as revealed by ultrafast pump probe spectroscopy
FEBS Letters, 1998Co-Authors: Sergei Savikhin, Robert E. Blankenship, Vladimir I. Novoderezhkin, Walter S. Struve, Daniel R Buck, A S Taisova, Z G FetisovaAbstract:Room temperature absorption difference spectra were measured on the femtosecond through picosecond time scales for chlorosomes isolated from the green bacterium Chloroflexus aurantiacus. Anomalously high values of photoinduced absorption changes were revealed in the BChl c Qy transition band. Photoinduced absorption changes at the bleaching peak in the BChl c band were found to be 7–8 times greater than those at the bleaching peak in the BChl a band of the chlorosome. This appears to be the first direct experimental proof of excitation delocalization over many BChl c antenna molecules in the chlorosome.
David M Ward - One of the best experts on this subject based on the ideXlab platform.
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Draft Genome Sequence of a Sulfide-Oxidizing, Autotrophic Filamentous Anoxygenic Phototrophic Bacterium, Chloroflexus sp. Strain MS-G (Chloroflexi)
Genome announcements, 2014Co-Authors: Vera Thiel, David M Ward, Trinity L. Hamilton, Lynn P. Tomsho, Richard Burhans, Stephan C. Schuster, Donald A. BryantAbstract:ABSTRACT The draft genome sequence of the thermophilic filamentous anoxygenic phototrophic bacterium Chloroflexus sp. strain MS-G (Chloroflexi), isolated from Mushroom Spring (Yellowstone National Park, WY, USA) was sequenced and comprises 4,784,183 bp in 251 contigs. The draft genome is predicted to encode 4,059 protein coding genes, 49 tRNA encoding genes, and 3 rRNA operons.
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Compound-specific isotopic fractionation patterns suggest different carbon metabolisms among Chloroflexus-like bacteria in hot-spring microbial mats.
Applied and environmental microbiology, 2003Co-Authors: Marcel T. J. Van Der Meer, Stefan Schouten, Jan W De Leeuw, Jaap S. Sinninghe Damsté, David M WardAbstract:Stable carbon isotope fractionations between dissolved inorganic carbon and lipid biomarkers suggest photoautotrophy by Chloroflexus-like organisms in sulfidic and nonsulfidic Yellowstone hot springs. Where co-occurring, cyanobacteria appear to cross-feed Chloroflexus-like organisms supporting photoheterotrophy as well, although the relatively small 13C fractionation associated with cyanobacterial sugar biosynthesis may sometimes obscure this process.
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Diversity and Distribution in Hypersaline Microbial Mats of Bacteria Related to Chloroflexus spp.
Applied and environmental microbiology, 2001Co-Authors: Ulrich Nübel, Michael T. Madigan, Mary M. Bateson, Michael Kühl, David M WardAbstract:Filamentous bacteria containing bacteriochlorophylls c and a were enriched from hypersaline microbial mats. Based on phylogenetic analyses of 16S rRNA gene sequences, these organisms form a previously undescribed lineage distantly related to Chloroflexus spp. We developed and tested a set of PCR primers for the specific amplification of 16S rRNA genes from filamentous phototrophic bacteria within the kingdom of “green nonsulfur bacteria.” PCR products recovered from microbial mats in a saltern in Guerrero Negro, Mexico, were subjected to cloning or denaturing gradient gel electrophoresis and then sequenced. We found evidence of a high diversity of bacteria related to Chloroflexus which exhibit different distributions along a gradient of salinity from 5.5 to 16%. Chloroflexus aurantiacus is a filamentous, bacteriochlorophyll-containing, metabolically versatile bacterium that is capable of anoxygenic photoautotrophy, photoheterotrophy, and aerobic chemoorganotrophy. A great interest in this organism from evolutionary, biochemical, and biogeochemical perspectives has been fueled by its deep branching in the bacterial phylogenetic tree, indicating its evolutionary antiquity (10, 27, 38), and by its unique pathway of carbon dioxide fixation (32, 33).
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autotrophy of green non sulphur bacteria in hot spring microbial mats biological explanations for isotopically heavy organic carbon in the geological record
Environmental Microbiology, 2000Co-Authors: Marcel T J Van Der Meer, Stefan Schouten, Jan W De Leeuw, David M WardAbstract:: Inferences about the evidence of life recorded in organic compounds within the Earth's ancient rocks have depended on 13C contents low enough to be characteristic of biological debris produced by the well-known CO2 fixation pathway, the Calvin cycle. 'Atypically' high values have been attributed to isotopic alteration of sedimentary organic carbon by thermal metamorphism. We examined the possibility that organic carbon characterized by a relatively high 13C content could have arisen biologically from recently discovered autotrophic pathways. We focused on the green non-sulphur bacterium Chloroflexus aurantiacus that uses the 3-hydroxypropionate pathway for inorganic carbon fixation and is geologically significant as it forms modern mat communities analogous to stromatolites. Organic matter in mats constructed by Chloroflexus spp. alone had relatively high 13C contents (-14.9%) and lipids diagnostic of Chloroflexus that were also isotopically heavy (-8.9% to -18.5%). Organic matter in mats constructed by Chloroflexus in conjunction with cyanobacteria had a more typical Calvin cycle signature (-23.5%). However, lipids diagnostic of Chloroflexus were isotopically enriched (-15.1% to -24.1%) relative to lipids typical of cyanobacteria (-33.9% to -36.3%). This suggests that, in mats formed by both cyanobacteria and Chloroflexus, autotrophy must have a greater effect on Chloroflexus carbon metabolism than the photoheterotrophic consumption of cyanobacterial photosynthate. Chloroflexus cell components were also selectively preserved. Hence, Chloroflexus autotrophy and selective preservation of its products constitute one purely biological mechanism by which isotopically heavy organic carbon could have been introduced into important Precambrian geological features.
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All-cis hentriaconta-9,15,22-triene in microbial mats formed by the phototrophic prokaryote Chloroflexus.
Organic geochemistry, 1999Co-Authors: Marcel T. J. Van Der Meer, Stefan Schouten, David M Ward, Jan A. J. Geenevasen, Jaap S. Sinninghe DamstéAbstract:All-cis hentriaconta-9,15,22-triene (I) has been isolated from Chloroflexus mats, Yellowstone National Park (USA), and identified by GC-(HR)MS analysis of I and its hydrogenated and DMDS-derivatized products and by 1H and 13C NMR spectroscopy.
Vladimir M. Gorlenko - One of the best experts on this subject based on the ideXlab platform.
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Chloroflexus islandicus sp. nov., a thermophilic filamentous anoxygenic phototrophic bacterium from a geyser
International journal of systematic and evolutionary microbiology, 2017Co-Authors: Vasil A. Gaisin, A. M. Kalashnikov, Denis S. Grouzdev, M. V. Sukhacheva, Boris B. Kuznetsov, Vladimir M. GorlenkoAbstract:A novel, thermophilic filamentous anoxygenic phototrophic bacterium, strain isl-2T, was isolated from the Strokkur Geyser, Iceland. Strain isl-2T formed unbranched multicellular filaments with gliding motility. The cells formed no spores and stained Gram-negative. The existence of pili was described in a species of the genus Chloroflexus for the first time, to our knowledge. Optimal growth occurred at a pH range of 7.5–7.7 and at a temperature of 55 °C. Strain isl-2T grew photoheterotrophically under anaerobic conditions in the light and chemoheterotrophically under aerobic conditions in the dark. The major cellular fatty acids were C18 : 1ω9, C16 : 0, C18 : 0 and C18 : 0-OH. The major quinone was menaquinone-10. The photosynthetic pigments were bacteriochlorophylls c and a as well as β- and γ-carotenes. The results of phylogenetic analysis of the 16S rRNA gene sequences placed strain isl-2T into the genus Chloroflexus of the phylum Chloroflexi with Chloroflexus aggregans DSM 9485T as the closest relative (97.0 % identity). The whole-genome sequence of isl-2T was determined. Average nucleotide identity values obtained for isl-2T in comparison to available genomic sequences of other strains of members of the genus Chloroflexus were 81.4 % or less and digital DNA–DNA hybridisation values 22.8 % or less. The results of additional phylogenetic analysis of the PufLM and BchG amino acid sequences supported the separate position of the isl-2T phylotype from the phylotypes of other members of the genus Chloroflexus . On the basis of physiological and phylogenetic data as well as genomic data, it was suggested that isl-2T represents a novel species within the genus Chloroflexus , with the proposed name Chloroflexus islandicus sp. nov. The type strain of the species is isl-2T (=VKM B-2978T,=DSM 29225T,=JCM 30533T).
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draft genome sequence of Chloroflexus sp strain isl 2 a thermophilic filamentous anoxygenic phototrophic bacterium isolated from the strokkur geyser iceland
Genome Announcements, 2016Co-Authors: Vasil A. Gaisin, Boris B. Kuznetsov, Vladimir M. Gorlenko, Timophey M Ivanov, Denis S. GrouzdevAbstract:ABSTRACT We report here the draft genome sequence of the thermophilic filamentous anoxygenic phototrophic bacterium Chloroflexus sp. strain isl-2, which was isolated from the Strokkur geyser, Iceland, and contains 5,222,563 bp with a G+C content of 59.65%. The annotated genome sequence offers the genetic basis for understanding the strain9s ecological role as a phototrophic bacterium within the bacterial community.
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Filamentous anoxygenic phototrophic bacteria from cyanobacterial mats of Alla hot springs (Barguzin Valley, Russia)
Extremophiles, 2015Co-Authors: Vasil A. Gaisin, Vladimir M. Gorlenko, Alexander M. Kalashnikov, Marina V. Sukhacheva, Zorigto B. Namsaraev, Darima D. Barhutova, Boris B. KuznetsovAbstract:Alkaline hydrotherms of the Baikal rift zone are unique systems to study the diversity of thermophilic bacteria. In this study, we present data on the phototrophic bacterial community of cyanobacterial mats from the alkaline Alla hot spring. Using a clonal analysis approach, this study evaluated the species diversity, the proportion of oxygenic and anoxygenic phototrophs and their distribution between various areas of the spring. Novel group-specific PCR primers were designed and applied to detect representatives of the Chloroflexus and Roseiflexus genera in mat samples. For the first time, the presence of Roseiflexus -like bacteria was detected in the Baikal rift zone.
Vasil A. Gaisin - One of the best experts on this subject based on the ideXlab platform.
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Chloroflexus islandicus sp. nov., a thermophilic filamentous anoxygenic phototrophic bacterium from a geyser
International journal of systematic and evolutionary microbiology, 2017Co-Authors: Vasil A. Gaisin, A. M. Kalashnikov, Denis S. Grouzdev, M. V. Sukhacheva, Boris B. Kuznetsov, Vladimir M. GorlenkoAbstract:A novel, thermophilic filamentous anoxygenic phototrophic bacterium, strain isl-2T, was isolated from the Strokkur Geyser, Iceland. Strain isl-2T formed unbranched multicellular filaments with gliding motility. The cells formed no spores and stained Gram-negative. The existence of pili was described in a species of the genus Chloroflexus for the first time, to our knowledge. Optimal growth occurred at a pH range of 7.5–7.7 and at a temperature of 55 °C. Strain isl-2T grew photoheterotrophically under anaerobic conditions in the light and chemoheterotrophically under aerobic conditions in the dark. The major cellular fatty acids were C18 : 1ω9, C16 : 0, C18 : 0 and C18 : 0-OH. The major quinone was menaquinone-10. The photosynthetic pigments were bacteriochlorophylls c and a as well as β- and γ-carotenes. The results of phylogenetic analysis of the 16S rRNA gene sequences placed strain isl-2T into the genus Chloroflexus of the phylum Chloroflexi with Chloroflexus aggregans DSM 9485T as the closest relative (97.0 % identity). The whole-genome sequence of isl-2T was determined. Average nucleotide identity values obtained for isl-2T in comparison to available genomic sequences of other strains of members of the genus Chloroflexus were 81.4 % or less and digital DNA–DNA hybridisation values 22.8 % or less. The results of additional phylogenetic analysis of the PufLM and BchG amino acid sequences supported the separate position of the isl-2T phylotype from the phylotypes of other members of the genus Chloroflexus . On the basis of physiological and phylogenetic data as well as genomic data, it was suggested that isl-2T represents a novel species within the genus Chloroflexus , with the proposed name Chloroflexus islandicus sp. nov. The type strain of the species is isl-2T (=VKM B-2978T,=DSM 29225T,=JCM 30533T).
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draft genome sequence of Chloroflexus sp strain isl 2 a thermophilic filamentous anoxygenic phototrophic bacterium isolated from the strokkur geyser iceland
Genome Announcements, 2016Co-Authors: Vasil A. Gaisin, Boris B. Kuznetsov, Vladimir M. Gorlenko, Timophey M Ivanov, Denis S. GrouzdevAbstract:ABSTRACT We report here the draft genome sequence of the thermophilic filamentous anoxygenic phototrophic bacterium Chloroflexus sp. strain isl-2, which was isolated from the Strokkur geyser, Iceland, and contains 5,222,563 bp with a G+C content of 59.65%. The annotated genome sequence offers the genetic basis for understanding the strain9s ecological role as a phototrophic bacterium within the bacterial community.
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Filamentous anoxygenic phototrophic bacteria from cyanobacterial mats of Alla hot springs (Barguzin Valley, Russia)
Extremophiles, 2015Co-Authors: Vasil A. Gaisin, Vladimir M. Gorlenko, Alexander M. Kalashnikov, Marina V. Sukhacheva, Zorigto B. Namsaraev, Darima D. Barhutova, Boris B. KuznetsovAbstract:Alkaline hydrotherms of the Baikal rift zone are unique systems to study the diversity of thermophilic bacteria. In this study, we present data on the phototrophic bacterial community of cyanobacterial mats from the alkaline Alla hot spring. Using a clonal analysis approach, this study evaluated the species diversity, the proportion of oxygenic and anoxygenic phototrophs and their distribution between various areas of the spring. Novel group-specific PCR primers were designed and applied to detect representatives of the Chloroflexus and Roseiflexus genera in mat samples. For the first time, the presence of Roseiflexus -like bacteria was detected in the Baikal rift zone.
Boris B. Kuznetsov - One of the best experts on this subject based on the ideXlab platform.
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Chloroflexus islandicus sp. nov., a thermophilic filamentous anoxygenic phototrophic bacterium from a geyser
International journal of systematic and evolutionary microbiology, 2017Co-Authors: Vasil A. Gaisin, A. M. Kalashnikov, Denis S. Grouzdev, M. V. Sukhacheva, Boris B. Kuznetsov, Vladimir M. GorlenkoAbstract:A novel, thermophilic filamentous anoxygenic phototrophic bacterium, strain isl-2T, was isolated from the Strokkur Geyser, Iceland. Strain isl-2T formed unbranched multicellular filaments with gliding motility. The cells formed no spores and stained Gram-negative. The existence of pili was described in a species of the genus Chloroflexus for the first time, to our knowledge. Optimal growth occurred at a pH range of 7.5–7.7 and at a temperature of 55 °C. Strain isl-2T grew photoheterotrophically under anaerobic conditions in the light and chemoheterotrophically under aerobic conditions in the dark. The major cellular fatty acids were C18 : 1ω9, C16 : 0, C18 : 0 and C18 : 0-OH. The major quinone was menaquinone-10. The photosynthetic pigments were bacteriochlorophylls c and a as well as β- and γ-carotenes. The results of phylogenetic analysis of the 16S rRNA gene sequences placed strain isl-2T into the genus Chloroflexus of the phylum Chloroflexi with Chloroflexus aggregans DSM 9485T as the closest relative (97.0 % identity). The whole-genome sequence of isl-2T was determined. Average nucleotide identity values obtained for isl-2T in comparison to available genomic sequences of other strains of members of the genus Chloroflexus were 81.4 % or less and digital DNA–DNA hybridisation values 22.8 % or less. The results of additional phylogenetic analysis of the PufLM and BchG amino acid sequences supported the separate position of the isl-2T phylotype from the phylotypes of other members of the genus Chloroflexus . On the basis of physiological and phylogenetic data as well as genomic data, it was suggested that isl-2T represents a novel species within the genus Chloroflexus , with the proposed name Chloroflexus islandicus sp. nov. The type strain of the species is isl-2T (=VKM B-2978T,=DSM 29225T,=JCM 30533T).
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draft genome sequence of Chloroflexus sp strain isl 2 a thermophilic filamentous anoxygenic phototrophic bacterium isolated from the strokkur geyser iceland
Genome Announcements, 2016Co-Authors: Vasil A. Gaisin, Boris B. Kuznetsov, Vladimir M. Gorlenko, Timophey M Ivanov, Denis S. GrouzdevAbstract:ABSTRACT We report here the draft genome sequence of the thermophilic filamentous anoxygenic phototrophic bacterium Chloroflexus sp. strain isl-2, which was isolated from the Strokkur geyser, Iceland, and contains 5,222,563 bp with a G+C content of 59.65%. The annotated genome sequence offers the genetic basis for understanding the strain9s ecological role as a phototrophic bacterium within the bacterial community.
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Filamentous anoxygenic phototrophic bacteria from cyanobacterial mats of Alla hot springs (Barguzin Valley, Russia)
Extremophiles, 2015Co-Authors: Vasil A. Gaisin, Vladimir M. Gorlenko, Alexander M. Kalashnikov, Marina V. Sukhacheva, Zorigto B. Namsaraev, Darima D. Barhutova, Boris B. KuznetsovAbstract:Alkaline hydrotherms of the Baikal rift zone are unique systems to study the diversity of thermophilic bacteria. In this study, we present data on the phototrophic bacterial community of cyanobacterial mats from the alkaline Alla hot spring. Using a clonal analysis approach, this study evaluated the species diversity, the proportion of oxygenic and anoxygenic phototrophs and their distribution between various areas of the spring. Novel group-specific PCR primers were designed and applied to detect representatives of the Chloroflexus and Roseiflexus genera in mat samples. For the first time, the presence of Roseiflexus -like bacteria was detected in the Baikal rift zone.