| microbial synthesis of poly((r)-3-hydroxybutyrate-co-3-hydroxypropionate) from unrelated carbon sources by engineered cupriavidus necator. | cupriavidus necator was engineered aiming to synthesize poly[(r)-3-hydroxybutyrate-co-3-hydroxypropionate] copolyester, p(3hb-co-3hp), from structurally unrelated carbon sources without addition of any precursor compounds. we modified a metabolic pathway in c. necator for generation of 3-hydroxypropionyl-coa (3hp-coa) by introducing malonyl-coa reductase and the 3hp-coa synthetase domain of trifunctional propionyl-coa synthase; both members of the 3-hydroxypropionate cycle, a novel co(2)-fixatio ... | 2009 | 19267466 |
| role of the acsf protein in chloroflexus aurantiacus. | the green phototrophic bacteria contain a unique complement of chlorophyll pigments, which self-assemble efficiently into antenna structures known as chlorosomes with little involvement of protein. the few proteins found in chlorosomes have previously been thought to have a primarily structural function. the biosynthetic pathway of the chlorosome pigments, bacteriochlorophylls c, d, and e, is not well understood. in this report, we used spectroscopic, proteomic, and gene expression approaches to ... | 2009 | 19346304 |
| purification and properties of a maltotetraose- and maltotriose-producing amylase from chloroflexus aurantiacus. | a maltotetraose- and maltotriose-producing amylase which is stable at alkaline phs and high temperatures was detected in the culture filtrate of a strain of chloroflexus aurantiacus j-10-f1, a thermophilic, green, photosynthetic bacterium. the enzyme was purified to homogeneity, as demonstrated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis, by means of ultrafiltration, ammonium sulfate fractionation, and deae-cellulose, hydroxyapatite, and high-performance liquid chromatographies. ... | 1992 | 16348751 |
| the role of diglycosyl lipids in photosynthesis and membrane lipid homeostasis in arabidopsis. | the galactolipid digalactosyldiacylglycerol (dgd) is an abundant thylakoid lipid in chloroplasts. the introduction of the bacterial lipid glucosylgalactosyldiacylglycerol (ggd) from chloroflexus aurantiacus into the dgd-deficient arabidopsis (arabidopsis thaliana) dgd1 mutant was previously shown to result in complementation of growth, but photosynthetic efficiency was only partially restored. here, we demonstrate that ggd accumulation in the double mutant dgd1dgd2, which is totally devoid of dg ... | 2009 | 19403724 |
| quantum chemical simulation of excited states of chlorophylls, bacteriochlorophylls and their complexes. | the present review describes the use of quantum chemical methods in estimation of structures and electronic transition energies of photosynthetic pigments in vacuum, in solution and imbedded in proteins. monomeric mg-porphyrins, chlorophylls and bacteriochlorophylls and their solvent 1:1 and 1:2 complexes were studied. calculations were performed for mg-porphyrin, mg-chlorin, mg-bacteriochlorin, mesochlorophyll a, chlorophylls a, b, c(1), c(2), c(3), d and bacteriochlorophylls a, b, c, d, e, f, ... | 2006 | 16482307 |
| exciton dynamics in the chlorosomal antenna of the green bacterium chloroflexus aurantiacus: experimental and theoretical studies of femtosecond pump-probe spectra. | femtosecond absorption difference spectra were measured for chlorosomes isolated from the green bacterium chloroflexus aurantiacus at room temperature. using the relative difference absorption of the oligomeric bchl c and monomeric bchl a bands, the size of a unit bchl c aggregate as well as the exciton coherence size were estimated for the chlorosomal bchl c antenna under study. a quantitative fit of the data was obtained within the framework of the exciton model proposed before [fetisova et al ... | 2002 | 16228498 |
| structural investigation of oxidized chlorosomes from green bacteria using multifrequency electron paramagnetic resonance up to 330 ghz. | chemical oxidation of the chlorosomes from chloroflexus aurantiacus and chlorobium tepidum green bacteria produces bacteriochlorophyll radicals, which are characterized by an anomalously narrow epr signal compared to in vitro monomeric bchl c (.+) [van noort pi, zhu y, lobrutto r and blankenship re (1997) biophys j 72: 316-325]. we have performed oxidant concentration and temperature-dependent x-band epr measurements in order to elucidate the line narrowing mechanism. the linewidth decreases as ... | 2002 | 16228499 |
| isolation and spectral characterization of photochemical reaction centers from the thermophilic green bacterium chloroflexus aurantiacus strain j-10-f1. | a rapid procedure has been devised to extract photochemically active reaction centers from the green bacterium chloroflexus aurantiacus strain j-10-f1 and a mutant lacking colored carotenoids (73-3). the isolated material was completely free of antenna bacteriochlorophyll and cytochromes and nearly free of carotenoids and had near ir absorption maxima at 865, 815, and 756 nm. on oxidation, the peak at 865 nm was bleached and the remaining two peaks were shifted to 806 and 757 nm. although these ... | 1983 | 16593269 |
| [search for an optimal orientational ordering of qy transition dipoles of subantennae molecules in superantenna of photosynthetic green bacteria. model calculations]. | this work continues a series of our investigations on efficient strategies of functioning of natural light-harvesting antennae, initiated by our concept of rigorous optimization of photosynthetic apparatus structure by functional criterion. using computer modeling for the functioning of the natural antennae, we suggested some basic principles for designing optimal model systems. targeted searches for these principles in in vivo systems allowed us to recognize some of them in natural antennae. th ... | 2009 | 19548533 |
| refolding, characterization and crystal structure of (s)-malate dehydrogenase from the hyperthermophilic archaeon aeropyrum pernix. | tartrate oxidation activity was found in the crude extract of an aerobic hyperthermophilic archaeon aeropyrum pernix, and the enzyme was identified as (s)-malate dehydrogenase (mdh), which, when produced in escherichia coli, was mainly obtained as an inactive inclusion body. the inclusion body was dissolved in 6 m guanidine-hcl and gradually refolded to the active enzyme through dilution of the denaturant. the purified recombinant enzyme consisted of four identical subunits with a molecular mass ... | 2009 | 19555779 |
| characterization of a blue-copper protein, auracyanin, of the filamentous anoxygenic phototrophic bacterium roseiflexus castenholzii. | a blue-copper protein auracyanin of the filamentous anoxygenic phototroph roseiflexus castenholzii was purified and characterized. genomic sequence analysis showed that r. castenholzii has only one auracyanin, whereas chloroflexus aurantiacus is known to have two auracyanins, a and b. absorption spectrum of the roseiflexus auracyanin was similar to that of auracyanin b of c. aurantiacus. on the other hand, esr spectrum of the roseiflexus auracyanin resembles that of auracyanin a of c. aurantiacu ... | 2009 | 19683508 |
| structure of chlorosomes from the green filamentous bacterium chloroflexus aurantiacus. | the green filamentous bacterium chloroflexus aurantiacus employs chlorosomes as photosynthetic antennae. chlorosomes contain bacteriochlorophyll aggregates and are attached to the inner side of a plasma membrane via a protein baseplate. the structure of chlorosomes from c. aurantiacus was investigated by using a combination of cryo-electron microscopy and x-ray diffraction and compared with that of chlorobi species. cryo-electron tomography revealed thin chlorosomes for which a distinct crystall ... | 2009 | 19717605 |
| [factors controlling the biosynthesis of chlorosome antenna bacteriochlorophylls in green filamentous anoxygenic phototrophic bacteria of the family oscillochloridaceae]. | we determined the concentrations of bacteriochlorophylls (bchl) in the light-harvesting antennae of oscillochloris trichoides (of the family oscillochloridaceae belonging to green filamentous mesophilic bacteria) cultivated either with gabaculine, an inhibitor of the c-5 pathway of bchl biosynthesis in a number of bacteria, or at various illumination intensities. we determined the bchl c: bchl a molar ratios in intact cells, in chlorosome-membrane complexes, and in isolated chlorosomes. we revea ... | 2006 | 16758863 |
| enzymatic activity of the alternative complex iii as a menaquinol:auracyanin oxidoreductase in the electron transfer chain of chloroflexus aurantiacus. | the surprising lack of the cytochrome bc1 complex in the filamentous anoxygenic phototrophic bacterium chloroflexus aurantiacus suggests that a functional replacement exists to link the cyclic electron transfer chain. earlier work identified the alternative complex iii (aciii) as a substitute of cytochrome bc1 complex. herein, the enzymatic activity of aciii is studied. the results strongly support the view that the aciii functions as menaquinol:auracyanin oxidoreductase in the c. aurantiacus el ... | 2009 | 19755122 |
| the cyanobacterial genome core and the origin of photosynthesis. | comparative analysis of 15 complete cyanobacterial genome sequences, including "near minimal" genomes of five strains of prochlorococcus spp., revealed 1,054 protein families [core cyanobacterial clusters of orthologous groups of proteins (core cyogs)] encoded in at least 14 of them. the majority of the core cyogs are involved in central cellular functions that are shared with other bacteria; 50 core cyogs are specific for cyanobacteria, whereas 84 are exclusively shared by cyanobacteria and pla ... | 2006 | 16924101 |
| spatial and temporal variability in a stratified hypersaline microbial mat community. | hypersaline microbial mat communities have recently been shown to be more diverse than once thought. the variability in community composition of hypersaline mats, both in terms of spatial and temporal dimensions, is still poorly understood. because this information is essential to understanding the complex biotic and abiotic interactions within these communities, terminal restriction fragment analysis and 16s rrna gene sequencing were used to characterize the near-surface community of a hypersal ... | 2009 | 19175677 |
| microbial diversity in natural environments: focusing on fundamental questions. | interactions with gijs kuenen and other dutch scientists have led my lab to fundamental insights into the composition, structure and function of a hot spring cyanobacterial mat community that should influence our thinking about all microbial communities. by focusing on the distribution of molecular sequence variants of predominant mat phototrophs, we have discovered that small-scale sequence variation can be ecologically meaningful. by applying novel cultivation approaches, we have been able to ... | 2006 | 17063383 |
| [biogeochemical processes in the algal-bacterial mats of the urinskii alkaline hot spring]. | the structure and production characteristics of microbial communities from the urinskii alkaline hot spring (buryat republic, russia) have been investigated. a distinctive characteristic of this hot spring is the lack of sulfide in the issuing water. the water temperature near the spring vents ranged from 69 to 38.5 degrees c and ph values ranged from 8.8 to 9.2. the total mineralization of water was less than 0.1 g/liter. temperature has a profound effect on the species composition and biogeoch ... | 2006 | 17091594 |
| the crystal structure of auracyanin a at 1.85 a resolution: the structures and functions of auracyanins a and b, two almost identical "blue" copper proteins, in the photosynthetic bacterium chloroflexus aurantiacus. | auracyanins a and b are two closely similar "blue" copper proteins produced by the filamentous anoxygenic phototrophic bacterium chloroflexus aurantiacus. both proteins have a water-soluble 140-residue globular domain, which is preceded in the sequence by an n-terminal tail. the globular domains of auracyanins a and b have sequences that are 38% identical. the sequences of the n-terminal tails, on the other hand, are distinctly different, suggesting that auracyanins a and b occupy different memb ... | 2009 | 19190939 |
| molecular signatures for the main phyla of photosynthetic bacteria and their subgroups. | the bacterial groups corresponding to different photosynthetic prokaryotes are presently identified mainly on the basis of their branching in phylogenetic trees. the availability of genome sequences is enabling identification of many molecular signatures that are specific for different groups of photosynthetic bacteria. our recent work has identified large numbers of signatures consisting of conserved inserts or deletions (indels) in widely distributed proteins, as well as whole proteins that ar ... | 2010 | 20414806 |
| pressure-induced red shift and broadening of the qy absorption of main light-harvesting antennae chlorosomes from green photosynthetic bacteria and their dependency upon alkyl substituents of the composite bacteriochlorophylls. | when pressure was applied to the main light-harvesting apparatus (chlorosomes) isolated from several green photosynthetic bacteria (up to 128 mpa), the qy-absorption band in an aqueous solution was shifted to longer wavelengths. the shift, deltav, was completely reversible for (de)compression and also showed a linear relation as a function of the applied pressure. the pressure-sensitivity in the deltav was dependent upon the bacterial species. the pressure coefficient, deltav/deltap, was -565 to ... | 2008 | 19367895 |
| properties of r-citramalyl-coenzyme a lyase and its role in the autotrophic 3-hydroxypropionate cycle of chloroflexus aurantiacus. | the autotrophic co(2) fixation pathway (3-hydroxypropionate cycle) in chloroflexus aurantiacus results in the fixation of two molecules of bicarbonate into one molecule of glyoxylate. glyoxylate conversion to the co(2) acceptor molecule acetyl-coenzyme a (coa) requires condensation with propionyl-coa (derived from one molecule of acetyl-coa and one molecule of co(2)) to beta-methylmalyl-coa, which is converted to citramalyl-coa. extracts of autotrophically grown cells contained both s- and r-cit ... | 2007 | 17259315 |
| optoelectronic energy transfer at novel biohybrid interfaces using light harvesting complexes from chloroflexus aurantiacus. | in nature, nanoscale supramolecular light harvesting complexes initiate the photosynthetic energy collection process at high quantum efficiencies. in this study, the distinctive antenna structure from chloroflexus aurantiacusthe chlorosomeis assessed for potential exploitation in novel biohybrid optoelectronic devices. electrochemical characterization of bacterial fragments containing intact chlorosomes with the photosynthetic apparatus show an increase in the charge storage density near the wor ... | 2009 | 19405485 |
| 3-hydroxypropionyl-coenzyme a dehydratase and acryloyl-coenzyme a reductase, enzymes of the autotrophic 3-hydroxypropionate/4-hydroxybutyrate cycle in the sulfolobales. | a 3-hydroxypropionate/4-hydroxybutyrate cycle operates in autotrophic co(2) fixation in various crenarchaea, as studied in some detail in metallosphaera sedula. this cycle and the autotrophic 3-hydroxypropionate cycle in chloroflexus aurantiacus have in common the conversion of acetyl-coenzyme a (coa) and two bicarbonates via 3-hydroxypropionate to succinyl-coa. both cycles require the reductive conversion of 3-hydroxypropionate to propionyl-coa. in m. sedula the reaction sequence is catalyzed b ... | 2009 | 19429610 |
| gradual adaptive changes of a protein facing high salt concentrations. | several experimental techniques were applied to unravel fine molecular details of protein adaptation to high salinity. we compared four homologous enzymes, which suggested a new halo-adaptive state in the process of molecular adaptation to high-salt conditions. together with comparative functional studies, the structure of malate dehydrogenase from the eubacterium salinibacter ruber shows that the enzyme shares characteristics of a halo-adapted archaea-bacterial enzyme and of non-halo-adapted en ... | 2010 | 20888835 |
| initial characterization of the photosynthetic apparatus of "candidatus chlorothrix halophila," a filamentous, anoxygenic photoautotroph. | "candidatus chlorothrix halophila" is a recently described halophilic, filamentous, anoxygenic photoautotroph (j. a. klappenbach and b. k. pierson, arch. microbiol. 181:17-25, 2004) that was enriched from the hypersaline microbial mats at guerrero negro, mexico. analysis of the photosynthetic apparatus by negative staining, spectroscopy, and sodium dodecyl sulfate-polyacrylamide gel electrophoresis indicated that the photosynthetic apparatus in this organism has similarities to the photosyntheti ... | 2007 | 17369303 |
| kinetics and energetics of electron transfer in reaction centers of the photosynthetic bacterium roseiflexus castenholzii. | the kinetics and thermodynamics of the photochemical reactions of the purified reaction center (rc)-cytochrome (cyt) complex from the chlorosome-lacking, filamentous anoxygenic phototroph, roseiflexus castenholzii are presented. the rc consists of l- and m-polypeptides containing three bacteriochlorophyll (bchl), three bacteriopheophytin (bph) and two quinones (q(a) and q(b)), and the cyt is a tetraheme subunit. two of the bchls form a dimer p that is the primary electron donor. at 285k, the lif ... | 2010 | 21126505 |
| diversity and function of chloroflexus-like bacteria in a hypersaline microbial mat: phylogenetic characterization and impact on aerobic respiration. | we studied the diversity of chloroflexus-like bacteria (clb) in a hypersaline phototrophic microbial mat and assayed their near-infrared (nir) light-dependent oxygen respiration rates. pcr with primers that were reported to specifically target the 16s rrna gene from members of the phylum chloroflexi resulted in the recovery of 49 sequences and 16 phylotypes (sequences of the same phylotype share more than 96% similarity), and 10 of the sequences (four phylotypes) appeared to be related to filame ... | 2007 | 17449697 |
| primary photochemistry in the facultatively aerobic green photosynthetic bacterium chloroflexus aurantiacus. | photochemical activity was examined in membrane fragments and a purified membrane preparation from chloroflexus. flash-induced absorption difference spectroscopy strongly suggests a primary donor (p(865)) that is more similar to the p(870) bacteriochlorophyll a dimer found in the purple photosynthetic bacteria than it is to p(840) found in the anaerobic green bacteria. redox measurements on p(865) and an early acceptor also indicate a photochemical system characteristic of the purple bacteria. t ... | 1982 | 16593246 |
| sulfur-metabolizing bacterial populations in microbial mats of the nakabusa hot spring, japan. | at the nakabusa hot spring, japan, dense olive-green microbial mats develop in regions where the slightly alkaline, sulfidic effluent has cooled to 65°c. the microbial community of such mats was analyzed by focusing on the diversity, as well as the in situ distribution and function of bacteria involved in sulfur cycling. analyses of 16s rrna and functional genes (apra, pufm) suggested the importance of three thermophilic bacterial groups: aerobic chemolithotrophic sulfide-oxidizing species of th ... | 2011 | 21353426 |
| polarized fluorescence of aggregated bacteriochlorophyll c and baseplate bacteriochlorophyll a in single chlorosomes isolated from chloroflexus aurantiacus. | the polarization anisotropy of fluorescence from single chlorosomes isolated from a green filamentous bacterium, chloroflexus aurantiacus, was measured using a confocal laser microscope at 13 k. each single chlorosome that is floating in a frozen solvent exhibited strong polarization anisotropy of fluorescence. we calculated the degrees of fluorescence polarization for 51 floating single chlorosomes. the value ranged from 0.1 to 0.76 for the bchl-c aggregate in the core chlorosomes and from 0 to ... | 2007 | 17503774 |
| contribution of chloroflexus respiration to oxygen cycling in a hypersaline microbial mat from lake chiprana, spain. | in dense stratified systems such as microbial mats, photosynthesis and respiration are coupled due to a tight spatial overlap between oxygen-producing and -consuming microorganisms. we combined microsensors and a membrane inlet mass spectrometer with two independent light sources emitting in the visible (vis) and near infrared (nir) regions to study this coupling in more detail. using this novel approach, we separately quantified the activity of the major players in the oxygen cycle in a hypersa ... | 2007 | 17635546 |
| ftir spectroscopy of the reaction center of chloroflexus aurantiacus: photoreduction of the bacteriopheophytin electron acceptor. | mid-infrared spectral changes associated with the photoreduction of the bacteriopheophytin electron acceptor h(a) in reaction centers (rcs) of the filamentous anoxygenic phototrophic bacterium chloroflexus (cfl.) aurantiacus are examined by light-induced fourier transform infrared (ftir) spectroscopy. the light-induced h(a)(-)/h(a) ftir (1800-1200cm(-1)) difference spectrum of cfl. aurantiacus rcs is compared to that of the previously well characterized purple bacterium rhodobacter (rba.) sphaer ... | 2011 | 21641333 |
| excitation energy transfer and trapping dynamics in the core complex of the filamentous photosynthetic bacterium roseiflexus castenholzii. | the light-harvesting core complex of the thermophilic filamentous anoxygenic phototrophic bacterium roseiflexus castenholzii is intrinsic to the cytoplasmic membrane and intimately bound to the reaction center (rc). using ultrafast transient absorption and time-resolved fluorescence spectroscopy with selective excitation, energy transfer, and trapping dynamics in the core complex have been investigated at room temperature in both open and closed rcs. results presented in this report revealed tha ... | 2011 | 21792612 |
| direct counting of submicrometer-sized photosynthetic apparatus dispersed in medium at cryogenic temperature by confocal laser fluorescence microscopy: estimation of the number of bacteriochlorophyll c in single light-harvesting antenna complexes chlorosomes of green photosynthetic bacteria. | the number of pigments in single light-harvesting complexes (chlorosomes) were calculated by imaging single chlorosomes in a frozen buffer at cryogenic temperature with a confocal laser fluorescence microscope and pigment extraction. chlorosomes were isolated from two types of green photosynthetic bacteria chlorobium (chl.) tepidum and chloroflexus (cfl.) aurantiacus and were individually imaged in the frozen medium. each fluorescence spot observed mainly came from a single chlorosome and was as ... | 2007 | 17918876 |
| phylogenetic and gene expression analysis of cyanobacteria and diatoms in the twilight waters of the temperate northeast pacific ocean. | in this study, to explore the microbial community structure and its functionality in the deep-sea environments, we initially performed a 16s ribosomal rna (rrna)-based community structure analyses for microbial communities in the sea water collected from sites of 765-790-ám in depth in the pacific ocean. interestingly, in the clone library we detected the presence of both photoautotrophic bacteria such as cyanobacteria and photoheterotrophic bacteria, such as chloroflexus sp. to further explore ... | 2011 | 21698402 |
| production of 3-hydroxypropionic acid via malonyl-coa pathway using recombinant escherichia coli strains. | malonyl-coa is an intermediary compound that is produced during fatty acid metabolism. our study aimed to produce the commercially important platform chemical 3-hydroxypropionic acid (3-hp) from its immediate precursor malonyl-coa by recombinant escherichia coli strains heterologously expressing the mcr gene of chloroflexus aurantiacus dsm 635, encoding an nadph-dependent malonyl-coa reductase (mcr). the recombinant e. coli overexpressing mcr under the t5 promoter showed mcr activity of 0.015umg ... | 2011 | 21723339 |
| screening and characterization of an enzyme with beta-glucosidase activity from environmental dna. | a novel beta-glucosidase gene, bgla, was isolated from uncultured soil bacteria and characterized. using genomic libraries constructed from soil dna, a gene encoding a protein that hydrolyzes a fluorogenic analog of cellulose, 4-methylumbelliferyl beta-d-cellobioside (muc), was isolated using a microtiter plate assay. the gene, bgla, was sequenced using a shotgun approach, and expressed in e. coli. the deduced 55-kda amino acid sequence for bgla showed a 56% identity with the family 1 glycosyl h ... | 2007 | 18050907 |
| immobilization of functional light antenna structures derived from the filamentous green bacterium chloroflexus aurantiacus. | the integration of highly efficient, natural photosynthetic light antenna structures into engineered systems while their biophotonic capabilities are maintained has been an elusive goal in the design of biohybrid photonic devices. in this study, we report a novel technique to covalently immobilize nanoscaled bacterial light antenna structures known as chlorosomes from chloroflexus aurantiacus on both conductive and nonconductive glass while their energy transducing functionality was maintained. ... | 2008 | 18590285 |
| two-dimensional mapping of photopigment distribution and activity of chloroflexus-like bacteria in a hypersaline microbial mat. | pigment analysis in an intact hypersaline microbial mat by hyperspectral imaging revealed very patchy and spatially uncorrelated distributions of photopigments chl a and bchl a/c, which are characteristic photopigments for oxygenic (diatoms and cyanobacteria) and anoxygenic phototrophs (chloroflexaceae). this finding is in contrast to the expectation that these biomarker pigments should be spatially correlated, as oxygenic phototrophs are thought to supply the chloroflexaceae members with organi ... | 2008 | 18616583 |
| photochemistry of a photosynthetic reaction center immobilized in lipidic cubic phases. | photosynthetic reaction centers, isolated and purified from the facultative phototrophic bacterium chloroflexus aurantiacus, were immobilized in optically transparent lipidic cubic phases composed of 42% (w/w) 1-palmitoyl-2-hydroxy-sn-glycero-3-phosphocholine and 58% (w/w) water. the immobilized photosynthetic protein retains its native properties, as indicated by visible and circular dichroic spectra. the ground state visible spectrum of the immobilized reaction centers is very similar to the c ... | 1995 | 18623268 |
| production of 3-hydroxypropionate homopolymer and poly(3-hydroxypropionate-co-4-hydroxybutyrate) copolymer by recombinant escherichia coli. | conversion of 3-hydroxypropionate (3hp) from 1,3-propanediol (pdo) was improved by expressing dehydratase gene (dhat) and aldehyde dehydrogenase gene (aldd) of pseudomonas putida kt2442 under the promoter of phacab operon from ralstonia eutropha h16. expression of these genes in aeromonas hydrophila 4ak4 produced up to 21 g/l 3hp in a fermentation process. to synthesize homopolymer poly(3-hydroxypropionate) (p3hp), and copolymer poly(3-hydroxypropionate-co-3-hydroxybutyrate) (p3hp4hb), dhat and ... | 2011 | 22024131 |
| wave packet motions coupled to electron transfer in reaction centers of chloroflexus aurantiacus. | transient absorption difference spectroscopy with approximately 20 femtosecond (fs) resolution was applied to study the time and spectral evolution of low-temperature (90 k) absorbance changes in isolated reaction centers (rcs) of chloroflexus (c.) aurantiacus. in rcs, the composition of the b-branch chromophores is different with respect to that of purple bacterial rcs by occupying the b(b) binding site of accessory bacteriochlorophyll by bacteriopheophytin molecule (phi(b)). it was found that ... | 2008 | 18763734 |
| comparison of chloroflexus aurantiacus strain j-10-fl proteomes of cells grown chemoheterotrophically and photoheterotrophically. | chloroflexus aurantiacus j-10-fl is a thermophilic green bacterium, a filamentous anoxygenic phototroph, and the model organism of the phylum chloroflexi. we applied high-throughput, liquid chromatography-mass spectrometry in a global quantitative proteomics investigation of c. aurantiacus cells grown under oxic (chemoorganoheterotrophically) and anoxic (photoorganoheterotrophically) redox states. our global analysis identified 13,524 high-confidence peptides that matched to 1,286 annotated prot ... | 2012 | 22249883 |
| purification, characterization and crystallization of menaquinol:fumarate oxidoreductase from the green filamentous photosynthetic bacterium chloroflexus aurantiacus. | the integral membrane protein complex, menaquinol:fumarate oxidoreductase (mqfr) has been purified, identified and characterized from the thermophilic green filamentous anoxygenic photosynthetic bacterium chloroflexus aurantiacus. the complex is composed of three subunits: a 74 kda flavoprotein that contains a covalently bound flavin adenine dinucleotide, a 28 kda iron-sulfur cluster-containing polypeptide, and a 27 kda transmembrane polypeptide, which is also the binding site of two b-type heme ... | 2009 | 19103151 |
| linear dichroism of chlorosomes from chloroflexus aurantiacus in compressed gels and electric fields. | the linear dichroism of chlorosomes from chloroflexus aurantiacus was measured between 250 and 800 nm. to orient the chlorosomes we used a new way of compressing polyacrylamide gels, where the dimension of the gel along the measuring light-beam is kept constant. the press required for such a way of compressing is relatively easy to construct. a theoretical description is given to interpret the measured linear dichroism in terms of the orientation of the transition moments. the results obtained w ... | 1988 | 19431726 |
| polarized fluorescence measurements on ordered photosynthetic antenna complexes: chlorosomes of chloroflexus aurantiacus and b800-b850 antenna complexes of rhodobacter sphaeroides. | we have used a new and relatively easy approach to study the pigment-organization in chlorosomes from the photosynthetic bacterium chloroflexus aurantiacus and in b800-850 antenna complexes of the photosynthetic purple bacterium rhodobacter sphaeroides. these particles were embedded in compressed and uncompressed gels and the polarized fluorescence was determined in a 90 degrees setup. assuming both a rotational symmetric distribution of the particles in the gel and of the transition dipole mome ... | 1991 | 19431792 |
| structural and functional analysis of a microbial mat ecosystem from a unique permanent hypersaline inland lake: 'la salada de chiprana' (ne spain). | the benthic microbial mat community of the only permanent hypersaline natural inland lake of western europe, 'la salada de chiprana', northeastern spain, was structurally and functionally analyzed. the ionic composition of the lake water is characterized by high concentrations of magnesium and sulfate, which were respectively 0.35 and 0.5 m at the time of sampling while the total salinity was 78 g l(-1). community composition was analyzed by microscopy, high-performance liquid chromatography (hp ... | 2003 | 19719635 |
| the hydroxypropionate pathway of co2 fixation: fait accompli. | | 2009 | 19996176 |
| in silico approaches to study mass and energy flows in microbial consortia: a syntrophic case study. | three methods were developed for the application of stoichiometry-based network analysis approaches including elementary mode analysis to the study of mass and energy flows in microbial communities. each has distinct advantages and disadvantages suitable for analyzing systems with different degrees of complexity and a priori knowledge. these approaches were tested and compared using data from the thermophilic, phototrophic mat communities from octopus and mushroom springs in yellowstone national ... | 2009 | 20003240 |
| cultivation and genomic, nutritional, and lipid biomarker characterization of roseiflexus strains closely related to predominant in situ populations inhabiting yellowstone hot spring microbial mats. | roseiflexus sp. strains were cultivated from a microbial mat of an alkaline siliceous hot spring in yellowstone national park. these strains are closely related to predominant filamentous anoxygenic phototrophs found in the mat, as judged by the similarity of small-subunit rrna, lipid distributions, and genomic and metagenomic sequences. like a japanese isolate, r. castenholzii, the yellowstone isolates contain bacteriochlorophyll a, but not bacteriochlorophyll c or chlorosomes, and grow photohe ... | 2010 | 20363941 |
| the small subunit arob of arsenite oxidase: lessons on the [2fe-2s] rieske protein superfamily. | here, we describe the characterization of the [2fe-2s] clusters of arsenite oxidases from rhizobium sp. nt-26 and ralstonia sp. 22. both reduced rieske proteins feature epr signals similar to their homologs from rieske-cyt b complexes, with g values at 2.027, 1.88, and 1.77. redox titrations in a range of ph values showed that both [2fe-2s] centers have constant e(m) values up to ph 8 at approximately +210 mv. above this ph value, the e(m) values of both centers are ph-dependent, similar to what ... | 2010 | 20421651 |
| kinetic and structural characterization of a heterohexamer 4-oxalocrotonate tautomerase from chloroflexus aurantiacus j-10-fl: implications for functional and structural diversity in the tautomerase superfamily . | 4-oxalocrotonate tautomerase (4-ot) isozymes play prominent roles in the bacterial utilization of aromatic hydrocarbons as sole carbon sources. these enzymes catalyze the conversion of 2-hydroxy-2,4-hexadienedioate (or 2-hydroxymuconate) to 2-oxo-3-hexenedioate, where pro-1 functions as a general base and shuttles a proton from the 2-hydroxyl group of the substrate to the c-5 position of the product. 4-ot, a homohexamer from pseudomonas putida mt-2, is the most extensively studied 4-ot isozyme a ... | 2010 | 20465238 |
| structural analysis of alternative complex iii in the photosynthetic electron transfer chain of chloroflexus aurantiacus. | the green photosynthetic bacterium chloroflexus aurantiacus, which belongs to the phylum of filamentous anoxygenic phototrophs, does not contain a cytochrome bc or bf type complex which is found in all other known groups of phototrophs. this suggests that a functional replacement exists to link the reaction center photochemistry to cyclic electron transfer as well as respiration. earlier work identified a potential substitute of the cytochrome bc complex, now named alternative complex iii (aciii ... | 2010 | 20614874 |
| comparative analysis of bacterioplankton assemblages from karenia brevis bloom and nonbloom water on the west florida shelf (gulf of mexico, usa) using 16s rrna gene clone libraries. | the brevetoxin-producing dinoflagellate, karenia brevis, forms nearly annual blooms off the florida west coast, severely impacting the region's ecology and economy. bacteria are often cited as either promoting or interfering with the development of algal blooms, and thus a detailed study of the bacterioplankton assemblages associated with k. brevis was undertaken. we developed sixteen 16s rrna gene clone libraries from k. brevis bloom and adjacent nonbloom water to determine the bacterial groups ... | 2010 | 20618855 |
| sans investigation of the photosynthetic machinery of chloroflexus aurantiacus. | green photosynthetic bacteria harvest light and perform photosynthesis in low-light environments, and contain specialized antenna complexes to adapt to this condition. we performed small-angle neutron scattering (sans) studies to obtain structural information about the photosynthetic apparatus, including the peripheral light-harvesting chlorosome complex, the integral membrane light-harvesting b808-866 complex, and the reaction center (rc) in the thermophilic green phototrophic bacterium chlorof ... | 2010 | 20959079 |
| a spectrophotometric assay for measuring acetyl-coenzyme a carboxylase. | acetyl-coenzyme a (coa) carboxylase catalyzes the first step in the biosynthesis of fatty acids in bacteria and eukaryota. this enzyme is the target of drug design for treatment of human metabolic diseases and of herbicides acting specifically on the eukaryotic form of the enzyme in grasses. acetyl-coa carboxylase activity screening in drug and herbicide design depends mostly on a time-consuming enzyme assay that is based on the incorporation of radiolabeled bicarbonate into the product malonyl- ... | 2010 | 21138728 |
| insights into chemotaxonomic composition and carbon cycling of phototrophic communities in an artesian sulfur-rich spring (zodletone, oklahoma, usa), a possible analog for ancient microbial mat systems. | zodletone spring in oklahoma is a unique environment with high concentrations of dissolved-sulfide (10 mm) and short-chain gaseous alkanes, exhibiting characteristics that are reminiscent of conditions that are thought to have existed in earth's history, in particular the late archean and early-to-mid proterozoic. here, we present a process-oriented investigation of the microbial community in two distinct mat formations at the spring source, (1) the top of the sediment in the source pool and (2) ... | 2011 | 21244620 |
| temperature and ionic strength effects on the chlorosome light-harvesting antenna complex. | chlorosomes, the peripheral light-harvesting antenna complex from green photosynthetic bacteria, are the largest and one of the most efficient light-harvesting antenna complexes found in nature. in contrast to other light-harvesting antennas, chlorosomes are constructed from more than 150,000 self-assembled bacteriochlorophylls (bchls) and contain relatively few proteins that play secondary roles. these unique properties have led to chlorosomes as an attractive candidate for developing biohybrid ... | 2011 | 21405043 |
| electronic pathway in reaction centers from rhodobacter sphaeroides and chloroflexus aurantiacus. | the reaction centers (rc) of chloroflexus aurantiacus and rhodobacter sphaeroidesh(m182)l mutant were investigated. prediction for electron transfer (et) at very low temperatures was also performed. to describe the kinetics of the c. aurantiacus rcs, the incoherent model of electron transfer was used. it was shown that the asymmetry in electronic coupling parameters must be included to explain the experiments. for the description of r. sphaeroidesh(m182)l mutant rcs, the coherent and incoherent ... | 2010 | 21629589 |
| co-assimilation of organic substrates via the autotrophic 3-hydroxypropionate bi-cycle in chloroflexus aurantiacus. | chloroflexus aurantiacus is a facultative autotrophic green non-sulfur bacterium that grows phototrophically in thermal springs and forms microbial mats with cyanobacteria. cyanobacteria produce glycolate during the day (photorespiration) and excrete fermentation products at night. c. aurantiacus uses the 3-hydroxypropionate bi-cycle for autotrophic carbon fixation. this pathway was supposed to be also suited for the co-assimilation of various organic substrates like glycolate, acetate, propiona ... | 2011 | 21764971 |
| comparing the temperature dependence of photosynthetic electron transfer in chloroflexus aurantiacus and rhodobactor sphaeroides reaction centers. | the process of electron transfer from the special pair, p, to the primary electron donor, h(a), in quinone-depleted reaction centers (rcs) of chloroflexus (cf.) aurantiacu s has been investigated over the temperature range from 10 to 295 k using time-resolved pump-probe spectroscopic techniques. the kinetics of the electron transfer reaction, p* ôåæ p(+)h(a)(-), was found to be nonexponential, and the degree of nonexponentiality increased strongly as temperature decreased. the temperature-depend ... | 2011 | 21827152 |
| complete genome sequence of the filamentous anoxygenic phototrophic bacterium chloroflexus aurantiacus. | 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 ... | 2011 | 21714912 |
| rhodobacter sphaeroides uses a reductive route via propionyl coenzyme a to assimilate 3-hydroxypropionate. | 3-hydroxypropionate is a product or intermediate of the carbon metabolism of organisms from all three domains of life. however, little is known about how carbon derived from 3-hydroxypropionate is assimilated by organisms that can utilize this c(3) compound as a carbon source. this work uses the model bacterium rhodobacter sphaeroides to begin to elucidate how 3-hydroxypropionate can be incorporated into cell constituents. to this end, a quantitative assay for 3-hydroxypropionate was developed b ... | 2012 | 22056933 |
| investigation of the redox interaction between mn-bicarbonate complexes and reaction centers from rhodobacter sphaeroides r-26, chromatium minutissimum, and chloroflexus aurantiacus. | the change in the dark reduction rate of photooxidized reaction centers (rc) of type ii from three anoxygenic bacteria (rhodobacter sphaeroides r-26, chromatium minutissimum, and chloroflexus aurantiacus) having different redox potentials of the p(+)/p pair and availability of rc for exogenous electron donors was investigated upon the addition of mn(2+) and hco(3)(-). it was found that the dark reduction of p(870)(+) from rb. sphaeroides r-26 is considerably accelerated upon the combined additio ... | 2011 | 22150281 |
| Dynamics of microbial community structure of and enhanced biological phosphorus removal by aerobic granules cultivated on propionate or acetate. | Aerobic granules are dense microbial aggregates with the potential to replace floccular sludge for the treatment of wastewaters. In bubble-column sequencing batch reactors, distinct microbial populations dominated propionate- and acetate-cultivated aerobic granules after 50 days of reactor operation when only carbon removal was detected. Propionate granules were dominated by Zoogloea (40%), Acidovorax, and Thiothrix, whereas acetate granules were mainly dominated by Thiothrix (60%). Thereafter, ... | 2011 | 21926195 |
| femtosecond phase of charge separation in reaction centers of chloroflexus aurantiacus. | difference absorption spectroscopy with temporal resolution of approximately 20 fsec was used to study the primary phase of charge separation in isolated reaction centers (rcs) of chloroflexus aurantiacus at 90 k. an ensemble of difference (light-minus-dark) absorption spectra in the 730-795 nm region measured at -0.1 to 4 psec delays relative to the excitation pulse was analyzed. comparison with analogous data for rcs of hm182l mutant of rhodobacter sphaeroides having the same pigment compositi ... | 2009 | 19817684 |
| identifying the missing steps of the autotrophic 3-hydroxypropionate co2 fixation cycle in chloroflexus aurantiacus. | the phototrophic bacterium chloroflexus aurantiacus uses a yet unsolved 3-hydroxypropionate cycle for autotrophic co(2) fixation. it starts from acetyl-coa, with acetyl-coa and propionyl-coa carboxylases acting as carboxylating enzymes. in a first cycle, (s)-malyl-coa is formed from acetyl-coa and 2 molecules of bicarbonate. (s)-malyl-coa cleavage releases the co(2) fixation product glyoxylate and regenerates the starting molecule acetyl-coa. here we complete the missing steps devoted to glyoxyl ... | 2009 | 19955419 |