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Francisco Castillo - One of the best experts on this subject based on the ideXlab platform.
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Expression and characterization of the assimilatory NADH-nitrite reductase from the Phototrophic Bacterium Rhodobacter capsulatus E1F1
Archives of Microbiology, 2006Co-Authors: M. Francisca Olmo-mira, Carmen Pino, Purificación Cabello, Manuel Martínez-luque, Francisco Castillo, M. Dolores Roldán, David J. Richardson, Conrado Moreno-viviánAbstract:A nas gene region from Rhodobacter capsulatus E1F1 containing the putative nasB gene for nitrite reductase was previously cloned. The recombinant His_6-NasB protein overproduced in E. coli showed nitrite reductase activity in vitro with both reduced methyl viologen and NADH as electron donors. The apparent K _ m values for nitrite and NADH were 0.5 mM and 20 μM, respectively, at the pH and temperature optima (pH 9 and 30°C). The optical spectrum showed features that indicate the presence of FAD, iron-sulfur cluster and siroheme as prosthetic groups, and nitrite reductase activity was inhibited by sulfide and iron reagents. These results indicate that the Phototrophic Bacterium R. capsulatus E1F1 possesses an assimilatory NADH-nitrite reductase similar to that described in non-Phototrophic organisms.
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the assimilatory nitrate reduction system of the Phototrophic Bacterium rhodobacter capsulatus e1f1
Biochemical Society Transactions, 2006Co-Authors: Carmen Pino, Purificación Cabello, Francisco Castillo, F Olmomira, Manuel Martinezluque, Maria Dolores Roldan, Conrado MorenovivianAbstract:The Phototrophic Bacterium Rhodobacter capsulatus E1F1 assimilates nitrate under anaerobic Phototrophic growth conditions. A 17 kb DNA region encoding the nitrate assimilation (nas) system of this Bacterium has been cloned and sequenced. This region includes the genes coding for a putative ABC (ATP-binding cassette)-type nitrate transporter (nasFED) and the structural genes for the enzymes nitrate reductase (nasA), nitrite reductase (nasB) and hydroxylamine reductase (hcp). Three genes code for putative regulatory proteins: a nitrite-sensitive repressor (nsrR), a transcription antiterminator (nasT) and a nitrate sensor (nasS). Other genes probably involved in nitrate assimilation are also present in this region. The sequence analysis of these genes and the biochemical properties of the purified nitrate, nitrite and hydroxylamine reductases are reviewed.
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periplasmic nitrate reducing system of the Phototrophic Bacterium rhodobacter sphaeroides dsm 158 transcriptional and mutational analysis of the napkefdabc gene cluster
Biochemical Journal, 1998Co-Authors: F Reyes, Francisco Castillo, Monica Gavira, Conrado MorenovivianAbstract:The Phototrophic Bacterium Rhodobacter sphaeroides DSM 158 is able to reduce nitrate to nitrite by means of a periplasmic nitrate reductase which is induced by nitrate and is not repressed by ammonium or oxygen. Recently, a 6.8 kb Pst I DNA fragment carrying the napABC genes coding for this periplasmic nitrate-reducing system was cloned [Reyes, Roldan, Klipp, Castillo and Moreno-Vivian (1996) Mol. Microbiol. 19 , 1307–1318]. Further sequence and genetic analyses of the DNA region upstream from the napABC genes reveal the presence of four additional nap genes. All these R. sphaeroides genes seem to be organized into a napKEFDABC transcriptional unit. In addition, a partial open reading frame similar to the Azorhizobium caulinodans yntC gene and the Escherichia coli yjcC and yhjK genes is present upstream from this nap gene cluster. The R. sphaeroides napK gene codes for a putative 6.3 kDa transmembrane protein which is not similar to known proteins and the napE gene codes for a 6.7 kDa transmembrane protein similar to the Thiosphaera pantotropha NapE. The R. sphaeroides napF gene product is a 16.4 kDa protein with four cysteine clusters that probably bind four [4Fe-4S] centres. This iron–sulphur protein shows similarity to the NapF and NapG proteins of E. coli and Haemophilus influenzae. Finally, the napD gene product is a 9.4 kDa soluble protein which is also found in E. coli and T. pantotropha . The 5´ end of the nap transcript has been determined by primer extension, and a δ 70 -like promoter has been identified upstream from the napK gene. The same transcriptional start site is found for cells growing aerobically or anaerobically with nitrate. Different mutant strains carrying defined polar and non-polar insertions in each nap gene were constructed. Characterization of these mutant strains demonstrates the participation of the nap gene products in the periplasmic nitrate reduction in R. sphaeroides.
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periplasmic nitrate reducing system of the Phototrophic Bacterium rhodobacter sphaeroides dsm 158 transcriptional and mutational analysis of the napkefdabc gene cluster
Biochemical Journal, 1998Co-Authors: F Reyes, Francisco Castillo, Monica Gavira, Conrado MorenovivianAbstract:The Phototrophic Bacterium Rhodobacter sphaeroides DSM 158 is able to reduce nitrate to nitrite by means of a periplasmic nitrate reductase which is induced by nitrate and is not repressed by ammonium or oxygen. Recently, a 6.8 kb PstI DNA fragment carrying the napABC genes coding for this periplasmic nitrate-reducing system was cloned [Reyes, Roldan, Klipp, Castillo and Moreno-Vivian (1996) Mol. Microbiol. 19, 1307-1318]. Further sequence and genetic analyses of the DNA region upstream from the napABC genes reveal the presence of four additional nap genes. All these R. sphaeroides genes seem to be organized into a napKEFDABC transcriptional unit. In addition, a partial open reading frame similar to the Azorhizobium caulinodans yntC gene and the Escherichia coli yjcC and yhjK genes is present upstream from this nap gene cluster. The R. sphaeroides napK gene codes for a putative 6.3 kDa transmembrane protein which is not similar to known proteins and the napE gene codes for a 6.7 kDa transmembrane protein similar to the Thiosphaera pantotropha NapE. The R. sphaeroides napF gene product is a 16.4 kDa protein with four cysteine clusters that probably bind four [4Fe-4S] centres. This iron-sulphur protein shows similarity to the NapF and NapG proteins of E. coli and Haemophilus influenzae. Finally, the napD gene product is a 9.4 kDa soluble protein which is also found in E. coli and T. pantotropha. The 5' end of the nap transcript has been determined by primer extension, and a sigma70-like promoter has been identified upstream from the napK gene. The same transcriptional start site is found for cells growing aerobically or anaerobically with nitrate. Different mutant strains carrying defined polar and non-polar insertions in each nap gene were constructed. Characterization of these mutant strains demonstrates the participation of the nap gene products in the periplasmic nitrate reduction in R. sphaeroides.
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Degradation of p-nitrophenol by the Phototrophic Bacterium Rhodobacter capsulatus
Archives of microbiology, 1997Co-Authors: Maria Dolores Roldan, Rafael Blasco, Francisco J Caballero, Francisco CastilloAbstract:The Phototrophic Bacterium Rhodobacter capsulatus detoxified p-nitrophenol and 4-nitrocatechol. The Bacterium tolerated moderate concentrations of p-nitrophenol (up to 0.5 mM) and degraded it under light at an optimal O2 pressure of 20 kPa. The Bacterium did not metabolize the xenobiotic in the dark or under strictly anoxic conditions or high O2 pressure. Bacterial growth with acetate in the presence of p-nitrophenol took place with the simultaneous release of nonstoichiometric amounts of 4-nitrocatechol, which can also be degraded by the Bacterium. Crude extracts from R. capsulatus produced 4-nitrocatechol from p-nitrophenol upon the addition of NAD(P)H, although at a very low rate. A constitutive catechol 1,2-dioxygenase activity yielding cis,cis-muconate was also detected in crude extracts of R. capsulatus. Further degradation of 4-nitrocatechol included both nitrite- and CO2-releasing steps since: (1) a strain of R. capsulatus (B10) unable to assimilate nitrate and nitrite released nitrite into the medium when grown with p-nitrophenol or 4-nitrocatechol, and the nitrite concentration was stoichiometric with the 4-nitrocatechol degraded, and (2) cultures of R. capsulatus growing microaerobically produced low amounts of 14CO2 from radiolabeled p-nitrophenol. The radioactivity was also incorporated into cellular compounds from cells grown with uniformly labeled 14C-p-nitrophenol. From these results we concluded that the xenobiotic is used as a carbon source by R. capsulatus, but that only the strain able to assimilate nitrite (E1F1) can use p-nitrophenol as a nitrogen source.
Robert E Blankenship - One of the best experts on this subject based on the ideXlab platform.
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light harvesting antenna system from the Phototrophic Bacterium roseiflexus castenholzii
Biochemistry, 2010Co-Authors: Aaron M Collins, Pu Qian, Qun Tang, David F Bocian, Neil C Hunter, Robert E BlankenshipAbstract:Photosynthetic organisms have evolved diverse light-harvesting complexes to harness light of various qualities and intensities. Photosynthetic bacteria can have (bacterio)chlorophyll Qy antenna absorption bands ranging from ∼650 to ∼1100 nm. This broad range of wavelengths has allowed many organisms to thrive in unique light environments. Roseiflexus castenholzii is a niche-adapted, filamentous anoxygenic phototroph (FAP) that lacks chlorosomes, the dominant antenna found in most green bacteria, and here we describe the purification of a full complement of photosynthetic complexes: the light-harvesting (LH) antenna, reaction center (RC), and core complex (RC-LH). By high-performance liquid chromatography separation of bacteriochlorophyll and bacteriopheophytin pigments extracted from the core complex and the RC, the number of subunits that comprise the antenna was determined to be 15 ± 1. Resonance Raman spectroscopy of the carbonyl stretching region displayed modes indicating that 3C-acetyl groups of BCh...
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Energy metabolism of HelioBacterium modesticaldum during Phototrophic and chemotrophic growth
BMC microbiology, 2010Co-Authors: Kuohsiang Tang, Hai Yue, Robert E BlankenshipAbstract:HelioBacterium modesticaldum is a gram-positive nitrogen-fixing Phototrophic Bacterium that can grow either photoheterotrophically or chemotrophically but not photoautotrophically. Surprisingly, this organism is lacking only one gene for the complete reverse tricarboxylic acid (rTCA) cycle required for autotrophic carbon fixation. Along with the genomic information reported recently, we use multiple experimental approaches in this report to address questions regarding energy metabolic pathways in darkness, CO2 fixation, sugar assimilation and acetate metabolism. We present the first experimental evidence that D-ribose, D-fructose and D-glucose can be photoassimilated by H. modesticaldum as sole carbon sources in newly developed defined growth medium. Also, we confirm two non-autotrophic CO2-fixation pathways utilized by H. modesticaldum: reactions catalyzed by pyruvate:ferredoxin oxidoreductase and phosphoenolpyruvate carboxykinase, and report acetate excretion during Phototrophic and chemotrophic growth. Further, genes responsible for pyruvate fermentation, which provides reducing power for nitrogen assimilation, carbon metabolism and hydrogen production, are either active or up-regulated during chemotrophic growth. The discovery of ferredoxin-NADP+ oxidoreductase (FNR) activity in cell extracts provides the reducing power required for carbon and nitrogen metabolisms. Moreover, we show that photosynthetic pigments are produced by H. modesticaldum during the chemotrophic growth, and demonstrate that H. modesticaldum performs nitrogen fixation during both Phototrophic and chemotrophic growth. Collectively, this report represents the first comprehensive studies for energy metabolism in heliobacteria, which have the simplest known photosynthetic machinery among the entire photosynthetic organisms. Additionally, our studies provide new and essential insights, as well as broaden current knowledge, on the energy metabolism of the thermophilic Phototrophic Bacterium H. modesticaldum during Phototrophic and chemotrophic growth.
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pigment analysis of candidatus chlorothrix halophila a green filamentous anoxygenic Phototrophic Bacterium
Journal of Bacteriology, 2007Co-Authors: Tien L Olson, Allison M L Van De Meene, Nicholas J Francis, Beverly K Pierson, Robert E BlankenshipAbstract:The pigment composition of "Candidatus Chlorothrix halophila," a filamentous anoxygenic Phototrophic Bacterium found in Baja California Sur, Mexico, was determined. Previous work showed that bacteriochlorophyll c (BChl c) was the major pigment in "Ca. Chlorothrix halophila," but it was not clear if this Bacterium also contains BChl a (J. A. Klappenbach and B. K. Pierson, Arch. Microbiol. 181:17-25, 2004). Here we show that in addition to BChl c, a small amount of a pigment that is spectrally indistinguishable from BChl a is present in cell extracts of "Ca. Chlorothrix halophila." Nevertheless, the BChl a-like pigment from "Ca. Chlorothrix halophila" has a different molecular weight and a different high-performance liquid chromatography elution time than BChl a from other photosynthetic bacteria. Based on mass spectrometry and other spectroscopic analysis, we determined that the BChl a-like pigment in "Ca. Chlorothrix halophila" contains a tetrahydrogeranylgeraniol tail rather than the phytol tail that is present in BChl a. The carotenoids and major BChl c homologs in "Ca. Chlorothrix halophila" were also identified. BChls c were found to be farnesol esterified and geranylgeraniol esterified.
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new class of bacterial membrane oxidoreductases
Biochemistry, 2005Co-Authors: Mikhail F Yanyushin, Melissa C Del Rosario, Daniel C Brune, Robert E BlankenshipAbstract:A new class of bacterial multisubunit membrane-bound electron-transfer complexes has been identified based on biochemical and bioinformatic data. It contains subunits homologous to the three-subunit molybdopterin oxidoreductases and four additional subunits, two of which are c-type cytochromes. The complex was purified from the filamentous anoxygenic Phototrophic Bacterium Chloroflexus aurantiacus, and putative operons for similar complexes were identified in a wide range of bacteria. In most cases, the presence of the new complex is anticorrelated with the cytochrome bc or bf electron-transfer complex, suggesting that it replaces it functionally. This appears to be a widespread yet previously unrecognized protein complex involved in energy metabolism in bacteria.
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isolation and characterization of the b798 light harvesting baseplate from the chlorosomes of chloroflexus aurantiacus
Biochemistry, 2003Co-Authors: Gabriel A Montano, Daniel C Brune, Su Lin, Robert E BlankenshipAbstract:The B798 light-harvesting baseplate of the chlorosome antenna complex of the thermophilic, filamentous anoxygenic Phototrophic Bacterium Chloroflexus aurantiacushas been isolated and character- ized. Isolation was performed by using a hexanol-detergent treatment of freeze-thawed chlorosomes. The isolated baseplate consists of Bchl a, ‚-carotene, and the 5.7 kDa CsmA protein with a ratio of 1.0 CsmA protein/1.6 Bchl a/4.2 ‚-carotenes. The baseplate has characteristic absorbance at 798 nm as well as carotenoid absorbance maxima at 519, 489, and 462 nm. The energy transfer efficiency from the carotenoids to the Bchl a is 30% as measured by steady-state and ultrafast time-resolved fluorescence and absorption spectroscopies. Energy equilibration within the Bchl a absorbing regions exhibits ultrafast kinetics. Circular dichroism spectroscopy shows no evidence for excitonically coupled Bchl a pools within the 798 nm region.
Conrado Morenovivian - One of the best experts on this subject based on the ideXlab platform.
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the assimilatory nitrate reduction system of the Phototrophic Bacterium rhodobacter capsulatus e1f1
Biochemical Society Transactions, 2006Co-Authors: Carmen Pino, Purificación Cabello, Francisco Castillo, F Olmomira, Manuel Martinezluque, Maria Dolores Roldan, Conrado MorenovivianAbstract:The Phototrophic Bacterium Rhodobacter capsulatus E1F1 assimilates nitrate under anaerobic Phototrophic growth conditions. A 17 kb DNA region encoding the nitrate assimilation (nas) system of this Bacterium has been cloned and sequenced. This region includes the genes coding for a putative ABC (ATP-binding cassette)-type nitrate transporter (nasFED) and the structural genes for the enzymes nitrate reductase (nasA), nitrite reductase (nasB) and hydroxylamine reductase (hcp). Three genes code for putative regulatory proteins: a nitrite-sensitive repressor (nsrR), a transcription antiterminator (nasT) and a nitrate sensor (nasS). Other genes probably involved in nitrate assimilation are also present in this region. The sequence analysis of these genes and the biochemical properties of the purified nitrate, nitrite and hydroxylamine reductases are reviewed.
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periplasmic nitrate reducing system of the Phototrophic Bacterium rhodobacter sphaeroides dsm 158 transcriptional and mutational analysis of the napkefdabc gene cluster
Biochemical Journal, 1998Co-Authors: F Reyes, Francisco Castillo, Monica Gavira, Conrado MorenovivianAbstract:The Phototrophic Bacterium Rhodobacter sphaeroides DSM 158 is able to reduce nitrate to nitrite by means of a periplasmic nitrate reductase which is induced by nitrate and is not repressed by ammonium or oxygen. Recently, a 6.8 kb Pst I DNA fragment carrying the napABC genes coding for this periplasmic nitrate-reducing system was cloned [Reyes, Roldan, Klipp, Castillo and Moreno-Vivian (1996) Mol. Microbiol. 19 , 1307–1318]. Further sequence and genetic analyses of the DNA region upstream from the napABC genes reveal the presence of four additional nap genes. All these R. sphaeroides genes seem to be organized into a napKEFDABC transcriptional unit. In addition, a partial open reading frame similar to the Azorhizobium caulinodans yntC gene and the Escherichia coli yjcC and yhjK genes is present upstream from this nap gene cluster. The R. sphaeroides napK gene codes for a putative 6.3 kDa transmembrane protein which is not similar to known proteins and the napE gene codes for a 6.7 kDa transmembrane protein similar to the Thiosphaera pantotropha NapE. The R. sphaeroides napF gene product is a 16.4 kDa protein with four cysteine clusters that probably bind four [4Fe-4S] centres. This iron–sulphur protein shows similarity to the NapF and NapG proteins of E. coli and Haemophilus influenzae. Finally, the napD gene product is a 9.4 kDa soluble protein which is also found in E. coli and T. pantotropha . The 5´ end of the nap transcript has been determined by primer extension, and a δ 70 -like promoter has been identified upstream from the napK gene. The same transcriptional start site is found for cells growing aerobically or anaerobically with nitrate. Different mutant strains carrying defined polar and non-polar insertions in each nap gene were constructed. Characterization of these mutant strains demonstrates the participation of the nap gene products in the periplasmic nitrate reduction in R. sphaeroides.
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periplasmic nitrate reducing system of the Phototrophic Bacterium rhodobacter sphaeroides dsm 158 transcriptional and mutational analysis of the napkefdabc gene cluster
Biochemical Journal, 1998Co-Authors: F Reyes, Francisco Castillo, Monica Gavira, Conrado MorenovivianAbstract:The Phototrophic Bacterium Rhodobacter sphaeroides DSM 158 is able to reduce nitrate to nitrite by means of a periplasmic nitrate reductase which is induced by nitrate and is not repressed by ammonium or oxygen. Recently, a 6.8 kb PstI DNA fragment carrying the napABC genes coding for this periplasmic nitrate-reducing system was cloned [Reyes, Roldan, Klipp, Castillo and Moreno-Vivian (1996) Mol. Microbiol. 19, 1307-1318]. Further sequence and genetic analyses of the DNA region upstream from the napABC genes reveal the presence of four additional nap genes. All these R. sphaeroides genes seem to be organized into a napKEFDABC transcriptional unit. In addition, a partial open reading frame similar to the Azorhizobium caulinodans yntC gene and the Escherichia coli yjcC and yhjK genes is present upstream from this nap gene cluster. The R. sphaeroides napK gene codes for a putative 6.3 kDa transmembrane protein which is not similar to known proteins and the napE gene codes for a 6.7 kDa transmembrane protein similar to the Thiosphaera pantotropha NapE. The R. sphaeroides napF gene product is a 16.4 kDa protein with four cysteine clusters that probably bind four [4Fe-4S] centres. This iron-sulphur protein shows similarity to the NapF and NapG proteins of E. coli and Haemophilus influenzae. Finally, the napD gene product is a 9.4 kDa soluble protein which is also found in E. coli and T. pantotropha. The 5' end of the nap transcript has been determined by primer extension, and a sigma70-like promoter has been identified upstream from the napK gene. The same transcriptional start site is found for cells growing aerobically or anaerobically with nitrate. Different mutant strains carrying defined polar and non-polar insertions in each nap gene were constructed. Characterization of these mutant strains demonstrates the participation of the nap gene products in the periplasmic nitrate reduction in R. sphaeroides.
Vladimir M. Gorlenko - One of the best experts on this subject based on the ideXlab platform.
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candidatus chloroploca mongolica sp nov a new mesophilic filamentous anoxygenic Phototrophic Bacterium
Fems Microbiology Letters, 2021Co-Authors: I A Bryantseva, Denis S. Grouzdev, Maria S Krutkina, A A Ashikhmin, Nadezda A Kostrikina, Veronika V Koziaeva, Vladimir M. GorlenkoAbstract:A mesophilic filamentous anoxygenic Phototrophic Bacterium, designated M50-1, was isolated from a microbial mat of the Chukhyn Nur soda lake (northeastern Mongolia) with salinity of 5-14 g/L and pH 8.0-9.3. The organism is a strictly anaerobic Phototrophic Bacterium, which required sulfide for Phototrophic growth. The cells formed short undulate trichomes surrounded by a thin sheath and containing gas vesicles. Motility of the trichomes was not observed. The cells contained chlorosomes. The antenna pigments were bacteriochlorophyll d and β- and γ-carotenes. Analysis of the genome assembled from the metagenome of the enrichment culture revealed all the enzymes of the 3-hydroxypropionate bi-cycle for autotrophic CO2 assimilation. The genome also contained the genes encoding a type IV sulfide:quinone oxidoreductase (sqrX). The organism had no nifHDBK genes, encoding the proteins of the nitrogenase complex responsible for dinitrogen fixation. The DNA G + C content was 58.6%. The values for in silico DNA‒DNA hybridization and average nucleotide identity between M50-1 and a closely related Bacterium 'Ca. Chloroploca asiatica' B7-9 containing bacteriochlorophyll c were 53.4% and 94.0%, respectively, which corresponds to interspecies differences. Classification of the filamentous anoxygenic Phototrophic Bacterium M50-1 as a new 'Ca. Chloroploca' species was proposed, with the species name 'Candidatus Chloroploca mongolica' sp. nov.
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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, Boris B. Kuznetsov, M. V. Sukhacheva, A. M. Kalashnikov, Denis S. Grouzdev, 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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candidatus chloroploca asiatica gen nov sp nov a new mesophilic filamentous anoxygenic Phototrophic Bacterium
Microbiology, 2014Co-Authors: Vladimir M. Gorlenko, M. V. Sukhacheva, Vasil A. Gaisin, A. M. Kalashnikov, I A Bryantseva, D S Gruzdev, B B KuznetsovAbstract:Five phylogenetically similar monocultures of mesophilic filamentous anoxygenic Phototrophic bacteria (FAPB) were isolated from microbial mats of low-mineral (5–28 g/L) alkaline lakes in Buryat Republic, Transbaikalia and Mongolia, as well as from biofilms of an alkaline sulfide spring (3 g/L) of the Umhei hydrothermal system (Buryat Republic). New isolates were characterized by short trichomes (15–30 μm long and ∼1 μm in diameter), straight, curved, or wavy, surrounded by a thin iron-sorbing mucous sheath. Gliding motion of the trichomes was not observed. The trichomes formed bunches consisting of several filaments. Trichomes multiply by the separation of short fragments or single cells from the parental trichome. The cells in the filaments were elongated; they contained chlorosomes, gas vesicles, poly-β-hydroxybutyrate granules, and small polyphosphate inclusions. Bacteria contained bacteriochlorophylls c and a and γ-carotene. Absorption maxima of the pigments in the cells were observed at 462, (shoulder at 515), 742, 805, and 863 nm. The organisms were strict anaerobes capable of photoautotrophic growth with sulfide as an electron donor. Elemental sulfur emerged into the medium as a result of sulfide photooxidation. The organisms were tolerant to sulfide (up to 8 mM). Best growth occurred at pH 8.0, 3–15 g/L NaCl, and 1–5 g/L sodium bicarbonate. According to phylogenetic analysis, the 16S rRNA gene sequences of the FAPB isolates formed a separate cluster most closely related to the species cluster of the family Oscillochloridaceae, suborder Chloroflexinae, order Chloroflexales, class Chloroflexi. The differences with the closest 16S rRNA gene sequences of the known FAPB were 9–10%. The formal description of a new taxon, Candidatus’ Chloroploca asiatica’ gen. nov., sp. nov., is provided.
Kuohsiang Tang - One of the best experts on this subject based on the ideXlab platform.
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complete genome sequence of the filamentous anoxygenic Phototrophic Bacterium chloroflexus aurantiacus
BMC Genomics, 2011Co-Authors: Kuohsiang Tang, Kerrie Barry, Olga Chertkov, Eileen Dalin, Cliff Han, Loren Hauser, Barbara M Honchak, Lauren E Karbach, Miriam LandAbstract:Background Chloroflexus aurantiacus is a thermophilic filamentous anoxygenic Phototrophic (FAP) Bacterium, and can grow Phototrophically under anaerobic conditions or chemotrophically under aerobic and dark conditions. According to 16S rRNA analysis, Chloroflexi species are the earliest branching bacteria capable of photosynthesis, and Cfl. aurantiacus has been long regarded as a key organism to resolve the obscurity of the origin and early evolution of photosynthesis. Cfl. aurantiacus contains a chimeric photosystem that comprises some characters of green sulfur bacteria and purple photosynthetic bacteria, and also has some unique electron transport proteins compared to other photosynthetic bacteria.
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Complete genome sequence of the filamentous anoxygenic Phototrophic Bacterium Chloroflexus aurantiacus
BMC Genomics, 2011Co-Authors: Kuohsiang Tang, Kerrie Barry, Olga Chertkov, Eileen Dalin, Barbara M Honchak, Lauren E Karbach, Loren J Hauser, Miriam L Land, Alla Lapidus, Frank W LarimerAbstract:Background Chloroflexus aurantiacus is a thermophilic filamentous anoxygenic Phototrophic (FAP) Bacterium, and can grow Phototrophically under anaerobic conditions or chemotrophically under aerobic and dark conditions. According to 16S rRNA analysis, Chloroflexi species are the earliest branching bacteria capable of photosynthesis, and Cfl. aurantiacus has been long regarded as a key organism to resolve the obscurity of the origin and early evolution of photosynthesis. Cfl. aurantiacus contains a chimeric photosystem that comprises some characters of green sulfur bacteria and purple photosynthetic bacteria, and also has some unique electron transport proteins compared to other photosynthetic bacteria. Methods The complete genomic sequence of Cfl. aurantiacus has been determined, analyzed and compared to the genomes of other photosynthetic bacteria. Results Abundant genomic evidence suggests that there have been numerous gene adaptations/replacements in Cfl. aurantiacus to facilitate life under both anaerobic and aerobic conditions, including duplicate genes and gene clusters for the alternative complex III (ACIII), auracyanin and NADH:quinone oxidoreductase; and several aerobic/anaerobic enzyme pairs in central carbon metabolism and tetrapyrroles and nucleic acids biosynthesis. Overall, genomic information is consistent with a high tolerance for oxygen that has been reported in the growth of Cfl. aurantiacus . Genes for the chimeric photosystem, photosynthetic electron transport chain, the 3-hydroxypropionate autotrophic carbon fixation cycle, CO_2-anaplerotic pathways, glyoxylate cycle, and sulfur reduction pathway are present. The central carbon metabolism and sulfur assimilation pathways in Cfl. aurantiacus are discussed. Some features of the Cfl. aurantiacus genome are compared with those of the Roseiflexus castenholzii genome. Roseiflexus castenholzii is a recently characterized FAP Bacterium and phylogenetically closely related to Cfl. aurantiacus . According to previous reports and the genomic information, perspectives of Cfl. aurantiacus in the evolution of photosynthesis are also discussed. Conclusions The genomic analyses presented in this report, along with previous physiological, ecological and biochemical studies, indicate that the anoxygenic phototroph Cfl. aurantiacus has many interesting and certain unique features in its metabolic pathways. The complete genome may also shed light on possible evolutionary connections of photosynthesis.
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complete genome sequence of the filamentous anoxygenic Phototrophic Bacterium chloroflexus aurantiacus
BMC Genomics, 2011Co-Authors: Kuohsiang Tang, Kerrie Barry, Olga Chertkov, Eileen Dalin, Cliff Han, Loren Hauser, Barbara M Honchak, Lauren E Karbach, Miriam LandAbstract:Chloroflexus aurantiacus is a thermophilic filamentous anoxygenic Phototrophic (FAP) Bacterium, and can grow Phototrophically under anaerobic conditions or chemotrophically under aerobic and dark conditions. According to 16S rRNA analysis, Chloroflexi species are the earliest branching bacteria capable of photosynthesis, and Cfl. aurantiacus has been long regarded as a key organism to resolve the obscurity of the origin and early evolution of photosynthesis. Cfl. aurantiacus contains a chimeric photosystem that comprises some characters of green sulfur bacteria and purple photosynthetic bacteria, and also has some unique electron transport proteins compared to other photosynthetic bacteria. The complete genomic sequence of Cfl. aurantiacus has been determined, analyzed and compared to the genomes of other photosynthetic bacteria. Abundant genomic evidence suggests that there have been numerous gene adaptations/replacements in Cfl. aurantiacus to facilitate life under both anaerobic and aerobic conditions, including duplicate genes and gene clusters for the alternative complex III (ACIII), auracyanin and NADH:quinone oxidoreductase; and several aerobic/anaerobic enzyme pairs in central carbon metabolism and tetrapyrroles and nucleic acids biosynthesis. Overall, genomic information is consistent with a high tolerance for oxygen that has been reported in the growth of Cfl. aurantiacus. Genes for the chimeric photosystem, photosynthetic electron transport chain, the 3-hydroxypropionate autotrophic carbon fixation cycle, CO2-anaplerotic pathways, glyoxylate cycle, and sulfur reduction pathway are present. The central carbon metabolism and sulfur assimilation pathways in Cfl. aurantiacus are discussed. Some features of the Cfl. aurantiacus genome are compared with those of the Roseiflexus castenholzii genome. Roseiflexus castenholzii is a recently characterized FAP Bacterium and phylogenetically closely related to Cfl. aurantiacus. According to previous reports and the genomic information, perspectives of Cfl. aurantiacus in the evolution of photosynthesis are also discussed. The genomic analyses presented in this report, along with previous physiological, ecological and biochemical studies, indicate that the anoxygenic phototroph Cfl. aurantiacus has many interesting and certain unique features in its metabolic pathways. The complete genome may also shed light on possible evolutionary connections of photosynthesis.
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Energy metabolism of HelioBacterium modesticaldum during Phototrophic and chemotrophic growth
BMC microbiology, 2010Co-Authors: Kuohsiang Tang, Hai Yue, Robert E BlankenshipAbstract:HelioBacterium modesticaldum is a gram-positive nitrogen-fixing Phototrophic Bacterium that can grow either photoheterotrophically or chemotrophically but not photoautotrophically. Surprisingly, this organism is lacking only one gene for the complete reverse tricarboxylic acid (rTCA) cycle required for autotrophic carbon fixation. Along with the genomic information reported recently, we use multiple experimental approaches in this report to address questions regarding energy metabolic pathways in darkness, CO2 fixation, sugar assimilation and acetate metabolism. We present the first experimental evidence that D-ribose, D-fructose and D-glucose can be photoassimilated by H. modesticaldum as sole carbon sources in newly developed defined growth medium. Also, we confirm two non-autotrophic CO2-fixation pathways utilized by H. modesticaldum: reactions catalyzed by pyruvate:ferredoxin oxidoreductase and phosphoenolpyruvate carboxykinase, and report acetate excretion during Phototrophic and chemotrophic growth. Further, genes responsible for pyruvate fermentation, which provides reducing power for nitrogen assimilation, carbon metabolism and hydrogen production, are either active or up-regulated during chemotrophic growth. The discovery of ferredoxin-NADP+ oxidoreductase (FNR) activity in cell extracts provides the reducing power required for carbon and nitrogen metabolisms. Moreover, we show that photosynthetic pigments are produced by H. modesticaldum during the chemotrophic growth, and demonstrate that H. modesticaldum performs nitrogen fixation during both Phototrophic and chemotrophic growth. Collectively, this report represents the first comprehensive studies for energy metabolism in heliobacteria, which have the simplest known photosynthetic machinery among the entire photosynthetic organisms. Additionally, our studies provide new and essential insights, as well as broaden current knowledge, on the energy metabolism of the thermophilic Phototrophic Bacterium H. modesticaldum during Phototrophic and chemotrophic growth.