Publications

b12-dependent ribonucleotide reductases from deeply rooted eubacteria are structurally related to the aerobic enzyme from escherichia coli.	the ribonucleotide reductases from three ancient eubacteria, the hyperthermophilic thermotoga maritima (tm), the radioresistant deinococcus radiodurans (dr), and the thermophilic photosynthetic chloroflexus aurantiacus, were found to be coenzyme-b12 (class ii) enzymes, similar to the earlier described reductases from the archaebacteria thermoplasma acidophila and pyrococcus furiosus. reduction of cdp by the purified tm and dr enzymes requires adenosylcobalamin and dtt. datp is a positive alloste ...	1997	9391052
redox effects on the excited-state lifetime in chlorosomes and bacteriochlorophyll c oligomers.	oligomers of [e,e] bchl cf (8, 12-diethyl bacteriochlorophyll c esterified with farnesol (f)) and [pr,e] bchl cf (analogously, m methyl, pr propyl) in hexane and aqueous detergent or lipid micelles were studied by means of steady-state absorption, time-resolved fluorescence, and electron spin resonance spectroscopy. the maximum absorption wavelength, excited-state dynamics, and electron spin resonance (epr) linewidths are similar to those of native and reconstituted chlorosomes of chlorobium tep ...	1997	8994616
evidence that eukaryotic triosephosphate isomerase is of alpha-proteobacterial origin.	we have cloned and sequenced genes for triosephosphate isomerase (tpi) from the gamma-proteobacterium francisella tularensis, the green non-sulfur bacterium chloroflexus aurantiacus, and the alpha-proteobacterium rhizobium etli and used these in phylogenetic analysis with tpi sequences from other members of the bacteria, archaea, and eukarya. these analyses show that eukaryotic tpi genes are most closely related to the homologue from the alpha-proteobacterium and most distantly related to archae ...	1997	9037042
biodiversity within hot spring microbial mat communities: molecular monitoring of enrichment cultures.	we have begun to examine the basis for incongruence between hot spring microbial mat populations detected by cultivation or by 16s rrna methods. we used denaturing gradient gel electrophoresis (dgge) to monitor enrichments and isolates plated therefrom. at near extincting inoculum dilutions we observed chloroflexus-like and cyanobacterial populations whose 16s rrna sequences have been detected in the 'new pit' spring chloroflexus mat and the octopus spring cyanobacterial mat. cyanobacterial popu ...	1997	9049026
structure and composition of freshwater microbial mats from a sulfur spring ("font pudosa", ne spain).	different types of microbial mats developing on the wall on a non-thermal sulfur freshwater spring have been studied. both, light and electron microscopy as well as hplc analysis of photosynthetic pigments revealed their structure and composition. prokaryotic chlorophylls and carotenoids helped in the taxonomical assignment of the main photosynthetic groups. "inverted position" mats (mat-i) were dominated by chromatiaceae; they were located closed to the water outlets (0.3 mm sulfide). "normal p ...	1997	9106181
mixed lipid-protein films of bacterial photosynthetic reaction centres. ii. mixed multilayers on solid supports.	mixed lipid-protein multilayers composed of the reaction centre (rc) proteins from the chloroflexus aurantiacus and rhodobacter sphaeroides (wild type) photosynthetic bacteria and synthetic lipids were investigated. the optimal conditions for forming thin films on solid plates (approximately 100% transfer) were 30 mn/m surface pressure and transfer of the interfacial monolayers from the buffer/air interface onto the plates by the langmuir-schaefer method. the films transferred onto quartz and op ...	1997	9225257
cloning, sequence analysis and expression in e. coli of the dna polymerase i gene from chloroflexus aurantiacus, a green nonsulfur eubacterium.	we have cloned and sequenced the pola gene from chloroflexus aurantiacus, a green nonsulfur eubacterium, and expressed the recombinant protein in escherichia coli. one open reading frame encodes a protein with 942 amino acids showing 38% identity with dna polymerase i from e. coli. sequence alignments with other members of dna polymerase family a and analysis of the separate domains show that the central 3'-5' exonuclease domain is 30% identical to the corresponding e. coli domain and that three ...	1998	9526698
energy transfers in the b808-866 antenna from the green bacterium chloroflexus aurantiacus.	energy transfers within the b808-866 bchl a antenna in chlorosome-membrane complexes from the green photosynthetic bacterium chloroflexus aurantiacus were studied in two-color pump-probe experiments at room temperature. the steady-state spectroscopy and protein sequence of the b808-866 complex are reminiscent of well-studied lh2 antennas from purple bacteria. b808-->b866 energy transfers occur with approximately 2 ps kinetics; this is slower by a factor of approximately 2 than b800-->b850 energy ...	1998	9545065
the phylogenetic relationships of chlorobium tepidum and chloroflexus aurantiacus based upon their reca sequences.	using reca as the phylogenetic marker, the relationships of the green sulfur bacterium chlorobium tepidum and the green non-sulfur bacterium chloroflexus aurantiacus to other eubacteria were investigated. the reca genes of the two organisms were cloned, and the resulting protein sequences aligned with 86 other eubacterial reca sequences. cb. tepidum was placed as the nearest relative to the cytophaga/flexibacter/bacteriodes group, a relationship supported by results obtained with several phyloge ...	1998	9595663
biosynthesis of the diterpene verrucosan-2beta-ol in the phototrophic eubacterium chloroflexus aurantiacus. a retrobiosynthetic nmr study.	the biosynthesis of verrucosan-2beta-ol in the green phototrophic eubacterium chloroflexus aurantiacus was investigated by in vivo incorporation of singly or doubly 13c-labeled acetate. the 13c labeling of the isolated diterpene was analyzed by one- and two-dimensional nmr spectroscopy. the 13c-labeling patterns of verrucosan-2beta-ol were compared with the labeling patterns of intermediary metabolites (acetyl-coa, pyruvate, and glyceraldehyde 3-phosphate) which were deduced from amino acids and ...	1998	9660767
pigment organization and exciton dynamics in the b808-866 antenna of the green bacterium chloroflexus aurantiacus.	the model for the b808-866 antenna of the green photosynthetic bacterium chloroflexus aurantiacus based on femtosecond pump-probe studies is proposed. the three-dimensional structure of the b808-866 antenna is assumed to be similar to the structure of the b800-850 antenna of purple bacteria, i.e. it has the form of two concentric rings of n strongly coupled bchl866 pigments and of n/2 weakly coupled bchl808 monomers. the qy transition dipoles of bchl808 and bchl866 molecules form the angles 43 d ...	1998	9678257
excitation delocalization in the bacteriochlorophyll c antenna of the green bacterium chloroflexus aurantiacus as revealed by ultrafast pump-probe spectroscopy.	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 firs ...	1998	9688564
characterization of the group 1 and group 2 sigma factors of the green sulfur bacterium chlorobium tepidum and the green non-sulfur bacterium chloroflexus aurantiacus.	the group 1 and group 2 sigma70-type sigma factors of the green sulfur bacterium chlorobium tepidum and of the green nonsulfur bacterium chloroflexus aurantiacus were cloned and characterized. cb. tepidum was found to contain one sigma70-type sigma factor; the expression of the gene was analyzed by northern blot hybridization and primer-extension mapping. cf. aurantiacus has genes encoding four sigma factors of groups 1 and 2. the expression of these genes was examined in cells grown aerobically ...	1998	9732443
phylogenetic heterogeneity within the genus herpetosiphon: transfer of the marine species herpetosiphon cohaerens, herpetosiphon nigricans and herpetosiphon persicus to the genus lewinella gen. nov. in the flexibacter-bacteroides-cytophaga phylum.	analysis of the 16s rdna sequences of species currently assigned to the genus herpetosiphon revealed intrageneric phylogenetic heterogeneity. the thermotolerant freshwater species herpetosiphon geysericola is most closely related to the type species herpetosiphon aurantiacus in the chloroflexus subdivision of the green non-sulfur bacteria. the marine species herpetosiphon cohaerens, herpetosiphon nigricans and herpetosiphon persicus, on the other hand, were found to form a cluster with sheathed ...	1998	9734027
photosynthesis and the origin of life.	the origin and evolution of photosynthesis is considered to be the key to the origin of life. this eliminates the need for a soup as the synthesis of the bioorganics are to come from the fixation of carbon dioxide and nitrogen. no soup then no rna world or protein world. cyanobacteria have been formed by the horizontal transfer of green sulfur bacterial photoreaction center genes by means of a plasmid into a purple photosynthetic bacterium. the fixation of carbon dioxide is considered to have ev ...	1998	11536891
changes in quinone profiles of hot spring microbial mats with a thermal gradient	the respiratory and photosynthetic quinones of microbial mats which occurred in japanese sulfide-containing neutral-ph hot springs at different temperatures were analyzed by spectrochromatography and mass spectrometry. all of the microbial mats that developed at high temperatures (temperatures above 68 degreesc) were so-called sulfur-turf bacterial mats and produced methionaquinones (mtks) as the major quinones. a 78 degreesc hot spring sediment had a similar quinone profile. chloroflexus-mixed ...	1999	9872780
presence of acetyl coenzyme a (coa) carboxylase and propionyl-coa carboxylase in autotrophic crenarchaeota and indication for operation of a 3-hydroxypropionate cycle in autotrophic carbon fixation.	the pathway of autotrophic co2 fixation was studied in the phototrophic bacterium chloroflexus aurantiacus and in the aerobic thermoacidophilic archaeon metallosphaera sedula. in both organisms, none of the key enzymes of the reductive pentose phosphate cycle, the reductive citric acid cycle, and the reductive acetyl coenzyme a (acetyl-coa) pathway were detectable. however, cells contained the biotin-dependent acetyl-coa carboxylase and propionyl-coa carboxylase as well as phosphoenolpyruvate ca ...	1999	9973333
taxon-specific content of oligonucleotide triplets in 16s rrnas of anoxygenic phototrophic and nitrifying bacteria.	theoretical evaluation of the content of oligonucleotide triplets aaa, ccc, and uau in 16s rrnas of anoxygenic phototrophic bacteria (genera chlorobium; chloroflexus; chromatium: rhodopseudomonas) and nitrifying bacteria (genera nitrosococcus, nitrosomonas, nitrosolobus, nitrosovibrio, nitrospira, nitrospina, nitrobacter) showed that the number of the aaa, ccc or uau triplets in 16s rrnas specifically corresponds to the genus and species of bacteria. the ratio of aaa and ccc triplet numbers in t ...	1999	10049622
auracyanin a from the thermophilic green gliding photosynthetic bacterium chloroflexus aurantiacus represents an unusual class of small blue copper proteins.	the amino acid sequence of the small copper protein auracyanin a isolated from the thermophilic photosynthetic green bacterium chloroflexus aurantiacus has been determined to be a polypeptide of 139 residues. his58, cys123, his128, and met132 are spaced in a way to be expected if they are the evolutionary conserved metal ligands as in the known small copper proteins plastocyanin and azurin. secondary structure prediction also indicates that auracyanin has a general beta-barrel structure similar ...	1999	10338005
evolutionary relationships among photosynthetic prokaryotes (heliobacterium chlorum, chloroflexus aurantiacus, cyanobacteria, chlorobium tepidum and proteobacteria): implications regarding the origin of photosynthesis.	the presence of shared conserved insertions or deletions in proteins (referred to as signature sequences) provides a powerful means to deduce the evolutionary relationships among prokaryotic organisms. this approach was used in the present work to deduce the branching orders of various eubacterial taxa consisting of photosynthetic organisms. for this purpose, portions of the hsp60 and hsp70 genes, covering known signature sequence regions, were pcr-amplified and sequenced from heliobacterium chl ...	1999	10361294
exciton delocalization in the b808-866 antenna of the green bacterium chloroflexus aurantiacus as revealed by ultrafast pump-probe spectroscopy.	a model of pigment organization in the b808-866 bacteriochlorophyll a antenna of the green photosynthetic bacterium chloroflexus aurantiacus based on femtosecond pump-probe studies is proposed. the building block of the antenna was assumed to be structurally similar to that of the b800-850 light-harvesting 2 (lh2) antenna of purple bacteria and to have the form of two concentric rings of n strongly coupled bchl866 pigments and of n/2 weakly coupled bchl808 monomers, where n = 24 or 32. we have s ...	1999	10388768
oxygen uncouples light absorption by the chlorosome antenna and photosynthetic electron transfer in the green sulfur bacterium chlorobium tepidum	in photosynthetic green sulfur bacteria excitation energy is transferred from large bacteriochlorophyll (bchl) c chlorosome antennas via small bchl a antennas to the reaction centers which then transfer electrons from cytochrome c to low-potential iron-sulfur proteins. under oxidizing conditions a reversible mechanism is activated in the chlorosomes which quenches excited bchl c. we used flash-induced cytochrome c oxidation to investigate the effect of this quenching on photosynthetic electron t ...	1999	10393254
exciton levels structure of antenna bacteriochlorophyll c aggregates in the green bacterium chloroflexus aurantiacus as probed by 1.8-293 k fluorescence spectroscopy.	we have demonstrated temperature-dependence of the steady-state fluorescence lineshape of the bacteriochlorophyll (bchl) c band measured for intact cells of the green bacterium chloroflexus aurantiacus over the 1.8-293 k range. the measured temperature-dependence has been shown to be in good agreement with the theoretical one, calculated for our original model of pigment organization in the chlorosomal oligomeric antenna of green photosynthetic bacteria based on spectral hole-burning studies (fe ...	1999	10456316
exogenous quinones inhibit photosynthetic electron transfer in chloroflexus aurantiacus by specific quenching of the excited bacteriochlorophyll c antenna.	in the photosynthetic green filamentous bacterium chloroflexus aurantiacus, excitation energy is transferred from a large bacteriochlorophyll (bchl) c antenna via smaller bchl a antennas to the reaction center. the effects of substituted 1,4-naphthoquinones on bchl c and bchl a fluorescence and on flash-induced cytochrome c oxidation were studied in whole cells under aerobic conditions. bchl c fluorescence in a cell suspension with 5.4 microm bchl c was quenched to 50% by addition of 0.6 microm ...	1999	10556623
association of bacteriochlorophyll a with the csma protein in chlorosomes of the photosynthetic green filamentous bacterium chloroflexus aurantiacus.	the protein assumed to be associated with bacteriochlorophyll (bchl) a in chlorosomes from the photosynthetic green filamentous bacterium chloroflexus aurantiacus was investigated by alkaline treatment, proteolytic digestion and a new treatment using 1-hexanol, sodium cholate and triton x-100. upon alkaline treatment, only the 5.7 kda csma protein was removed from the chlorosomes among six proteins detected by sodium dodecyl sulfate polyacrylamide gel electrophoresis (sds-page) analysis, concomi ...	1999	10556629
all-cis hentriaconta-9,15,22-triene in microbial mats formed by the phototrophic prokaryote chloroflexus.	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.	1999	11543197
[on the mechanism of autotrophic fixation of carbone dioxide by chloroflexus aurantiacus].	the activity of two carboxylating enzymes was studied in the green filamentous bacterium chloroflexus aurantiacus. the carboxylation reaction involving pyruvate synthase was optimized using 14co2 and cell extracts. pyruvate synthase was shown to be absent from cells of cfl. aurantiacus ok-70 and present (in a quantity sufficient to account for autotrophic growth) in cells of cfl. aurantiacus b-3. differences in the levels of acetyl coa carboxylase activity were revealed between cells of the stra ...	2000	10776614
phototrophs in high iron microbial mats: microstructure of mats in iron-depositing hot springs.	chocolate pots hot springs in yellowstone national park are high in ferrous iron, silica and bicarbonate. the springs are contributing to the active development of an iron formation. the microstructure of photosynthetic microbial mats in these springs was studied with conventional optical microscopy, confocal laser scanning microscopy and transmission electron microscopy. the dominant mats at the highest temperatures (48-54 degrees c) were composed of synechococcus and chloroflexus or pseudanaba ...	2000	10858577
influence of sulfide and temperature on species composition and community structure of hot spring microbial mats.	in solfataric fields in southwestern iceland, neutral and sulfide-rich hot springs are characterized by thick bacterial mats at 60 to 80 degrees c that are white or yellow from precipitated sulfur (sulfur mats). in low-sulfide hot springs in the same area, grey or pink streamers are formed at 80 to 90 degrees c, and a chloroflexus mat is formed at 65 to 70 degrees c. we have studied the microbial diversity of one sulfur mat (high-sulfide) hot spring and one chloroflexus mat (low-sulfide) hot spr ...	2000	10877776
proposal of oscillochloridaceae fam. nov. on the basis of a phylogenetic analysis of the filamentous anoxygenic phototrophic bacteria, and emended description of oscillochloris and oscillochloris trichoides in comparison with further new isolates.	the nucleotide sequences of the genes of 16s rrnas were determined for the type strain oscillochloris trichoides dg-6t and three new strains of oscillochloris-like mesophilic filamentous green bacteria. two major clusters have been found within the family chloroflexaceae by phylogenetic-analysis: one cluster includes thermophilic species of chloroflexus and the second includes mesophilic strains of oscillochloris. the degree of relatedness of these clusters was below an intergeneric level, havin ...	2000	10939660
molecular evidence for the early evolution of photosynthesis.	the origin and evolution of photosynthesis have long remained enigmatic due to a lack of sequence information of photosynthesis genes across the entire photosynthetic domain. to probe early evolutionary history of photosynthesis, we obtained new sequence information of a number of photosynthesis genes from the green sulfur bacterium chlorobium tepidum and the green nonsulfur bacterium chloroflexus aurantiacus. a total of 31 open reading frames that encode enzymes involved in bacteriochlorophyll/ ...	2000	10976061
quenching of bacteriochlorophyll fluorescence in chlorosomes from chloroflexus aurantiacus by exogenous quinones.	the quenching of bacteriochlorophyll (bchl) c fluorescence in chlorosomes isolated from chloroflexus aurantiacus was examined by the addition of various benzoquinones, naphthoquinones (nq), and anthraquinones (aq). many quinones showed strong quenching in the micromolar or submicromolar range. the number of quinone molecules bound to the chlorosomes was estimated to be as small as one quinone molecule per 50 bchl c molecules. quinones which exhibit a high quenching effect have sufficient hydroph ...	2000	10989605
electronic energy transfer involving carotenoid pigments in chlorosomes of two green bacteria: chlorobium tepidum and cholroflexus aurantiacus.	electronic energy transfer processes in chlorosomes isolated from the green sulphur bacterium chlorobium tepidum and from the green filamentous bacterium chloroflexus aurantiacus have been investigated. steady-state fluorescence excitation spectra and time-resolved triplet-minus-singlet (tms) spectra, recorded at ambient temperature and under non-reducing or reducing conditions, are reported. the carotenoid (car) pigments in both species transfer their singlet excitation to bacteriochlorophyll c ...	2000	10989892
exciton dynamics in the chlorosomal antennae of the green bacteria chloroflexus aurantiacus and chlorobium tepidum.	the energy transfer processes in isolated chlorosomes from green bacteria chlorobium tepidum and chloroflexus aurantiacus have been studied at low temperatures (1.27 k) by two-pulse photon echo and one-color transient absorption techniques with approximately 100 fs resolution. the decay of the coherence in both types of chlorosomes is characterized by four different dephasing times stretching from approximately 100 fs up to 300 ps. the fastest component reflects dephasing that is due to interact ...	2000	11023914
autotrophy of green non-sulphur bacteria in hot spring microbial mats: biological explanations for isotopically heavy organic carbon in the geological record.	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 ...	2000	11234931
autotrophic co(2) fixation by chloroflexus aurantiacus: study of glyoxylate formation and assimilation via the 3-hydroxypropionate cycle.	in the facultative autotrophic organism chloroflexus aurantiacus, a phototrophic green nonsulfur bacterium, the calvin cycle does not appear to be operative in autotrophic carbon assimilation. an alternative cyclic pathway, the 3-hydroxypropionate cycle, has been proposed. in this pathway, acetyl coenzyme a (acetyl-coa) is assumed to be converted to malate, and two co(2) molecules are thereby fixed. malyl-coa is supposed to be cleaved to acetyl-coa, the starting molecule, and glyoxylate, the car ...	2001	11418572
photosynthetic and phylogenetic primers for detection of anoxygenic phototrophs in natural environments.	primer sets were designed to target specific 16s ribosomal dna (rdna) sequences of photosynthetic bacteria, including the green sulfur bacteria, the green nonsulfur bacteria, and the members of the heliobacteriaceae (a gram-positive phylum). due to the phylogenetic diversity of purple sulfur and purple nonsulfur phototrophs, the 16s rdna gene was not an appropriate target for phylogenetic rdna primers. thus, a primer set was designed that targets the pufm gene, encoding the m subunit of the phot ...	2001	11425703
biosynthetic controls on the 13c contents of organic components in the photoautotrophic bacterium chloroflexus aurantiacus.	to assess the effects related to known and proposed biosynthetic pathways on the (13)c content of lipids and storage products of the photoautotrophic bacterium chloroflexus aurantiacus, the isotopic compositions of bulk cell material, alkyl and isoprenoid lipids, and storage products such as glycogen and polyhydroxyalkanoic acids have been investigated. the bulk cell material was 13 per thousand depleted in (13)c relative to the dissolved inorganic carbon. evidently, inorganic carbon fixation by ...	2001	11439929
diversity and distribution in hypersaline microbial mats of bacteria related to chloroflexus spp.	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 i ...	2001	11526049
biosynthetic controls on the 13c contents of organic components in the photoautotrophic bacterium chloroflexus aurantiacus.	to assess the effects related to known and proposed biosynthetic pathways on the (13)c content of lipids and storage products of the photoautotrophic bacterium chloroflexus aurantiacus, the isotopic compositions of bulk cell material, alkyl and isoprenoid lipids, and storage products such as glycogen and polyhydroxyalkanoic acids have been investigated. the bulk cell material was 13 per thousand depleted in (13)c relative to the dissolved inorganic carbon. evidently, inorganic carbon fixation by ...	2001	11145961
crystal structure of auracyanin, a "blue" copper protein from the green thermophilic photosynthetic bacterium chloroflexus aurantiacus.	auracyanin b, one of two similar blue copper proteins produced by the thermophilic green non-sulfur photosynthetic bacterium chloroflexus aurantiacus, crystallizes in space group p6(4)22 (a=b=115.7 a, c=54.6 a). the structure was solved using multiple wavelength anomalous dispersion data recorded about the cuk absorption edge, and was refined at 1.55 a resolution. the molecular model comprises 139 amino acid residues, one cu, 247 h(2)o molecules, one cl(-) and two so(4)(2-). the final residual a ...	2001	11178893
propionyl-coenzyme a synthase from chloroflexus aurantiacus, a key enzyme of the 3-hydroxypropionate cycle for autotrophic co2 fixation.	the 3-hydroxypropionate cycle has been proposed as a new autotrophic co(2) fixation pathway for the phototrophic green non-sulfur eubacterium chloroflexus aurantiacus and for some chemotrophic archaebacteria. the cycle requires the reductive conversion of the characteristic intermediate 3-hydroxypropionate to propionyl-coa. the specific activity of the 3-hydroxypropionate-, coa-, k(+)-, and mgatp-dependent oxidation of nadph in autotrophically grown cells was 0.09 micromol min(-1) mg(-1) protein ...	2002	11821399
roseiflexus castenholzii gen. nov., sp. nov., a thermophilic, filamentous, photosynthetic bacterium that lacks chlorosomes.	a novel thermophilic, photosynthetic bacterium, designated strain hlo8t, was isolated from a bacterial mat in a japanese hot spring. morphologically, the isolate was an unbranched multicellular filament with a cell diameter of 0.8-1.0 microm. the bacterium was red to reddish-brown in colour and formed a distinct red bacterial mat in the natural environment. it was able to grow photoheterotrophically under anaerobic light conditions and also chemoheterotrophically under aerobic dark conditions. o ...	2002	11837302
fractionation of cytochromes of phototrophically grown chloroflexus aurantiacus. is there a cytochrome bc complex among them?	the cytochrome-containing membrane complexes of the phototrophically grown green non-sulfur bacterium chloroflexus aurantiacus were fractionated by anion exchange chromatography. three cytochrome b and four cytochrome c peaks were observed. none of the separated complexes met the features of the cytochrome bc complex. two main cytochrome b-containing complexes were further purified: a dimer of identical subunits with unknown function and a succinate:quinone oxidoreductase containing three subuni ...	2002	11852065
light control over the size of an antenna unit building block as an efficient strategy for light harvesting in photosynthesis.	it was shown that an increase in the bacteriochlorophyll (bchl) c antenna size observed upon lowering growth light intensities led to enhancement of the hyperchromism of the bchl c q(y) absorption band of the green photosynthetic bacterium chloroflexus aurantiacus. with femtosecond difference absorption spectroscopy, it was shown that the amplitude of bleaching of the oligomeric bchl c q(y) band (as compared to that for monomeric bchl a) increased with increasing bchl c content in chlorosomes. t ...	2002	11852066
subcellular localization of chlorosome proteins in chlorobium tepidum and characterization of three new chlorosome proteins: csmf, csmh, and csmx.	chlorosomes are unique light-harvesting structures found in two families of photosynthetic bacteria. in this study, three chlorosome proteins (csmf, csmh, and csmx) of the green sulfur bacterium chlorobium tepidum were characterized by cloning and sequencing the genes which encode them, by overproducing the respective proteins in escherichia coli, and by raising polyclonal antisera to the purified proteins. three other proteins (atpf, ct1970, and ct2144) which were identified in chlorosome fract ...	2002	11914082
a bicyclic autotrophic co2 fixation pathway in chloroflexus aurantiacus.	phototrophic co(2) assimilation by the primitive, green eubacterium chloroflexus aurantiacus has been shown earlier to proceed in a cyclic mode via 3-hydroxypropionate, propionyl-coa, succinyl-coa, and malyl-coa. the metabolic cycle could be closed by cleavage of malyl-coa affording glyoxylate (the primary co(2) fixation product) with regeneration of acetyl-coa serving as the starter unit of the cycle. the pathway of glyoxylate assimilation to form gluconeogenic precursors has not been elucidate ...	2002	11929869
malonyl-coenzyme a reductase from chloroflexus aurantiacus, a key enzyme of the 3-hydroxypropionate cycle for autotrophic co(2) fixation.	the 3-hydroxypropionate cycle is a new autotrophic co(2) fixation pathway in chloroflexus aurantiacus and some archaebacteria. the initial step is acetyl-coenzyme a (coa) carboxylation to malonyl-coa by acetyl-coa carboxylase, followed by nadph-dependent reduction of malonyl-coa to 3-hydroxypropionate. this reduction step was studied in chloroflexus aurantiacus. a new enzyme was purified, malonyl-coa reductase, which catalyzed the two-step reduction malonyl-coa + nadph + h(+) --> malonate semial ...	2002	11948153
active and energy-dependent rapid formation of cell aggregates in the thermophilic photosynthetic bacterium chloroflexus aggregans.	the thermophilic filamentous phototroph chloroflexus aggregans was able to form a bacterial mat-like dense cell aggregate rapidly. the aggregate formation, which was observed in growing cells in a liquid medium in a bottle, occurred every time within 20-30 min after the cells were dispersed by shaking. the aggregation depended on the energy supplied by photosynthesis or respiration. cells aggregated most rapidly under temperature and ph conditions that support maximum growth. the aggregation was ...	2002	11959449
spectral heterogeneity in single light-harvesting chlorosomes from green sulfur photosynthetic bacterium chlorobium tepidum.	the fluorescence emission properties of single chlorosomes from the green sulfur photosynthetic bacterium chlorobium (chl.) tepidum are studied for the first time, using a total internal reflection fluorescence microscope. the fluorescence peak positions of bacteriochlorophyll (bchl)-c self-aggregates in a single chlorosome of chl. tepidum were widely distributed in the wavelength region between 750 and 768 nm, and the standard deviation (s.d. = 4.1 nm, n = 51) was larger than that of single chl ...	2002	12003135
structural basis for thermophilic protein stability: structures of thermophilic and mesophilic malate dehydrogenases.	the three-dimensional structure of four malate dehydrogenases (mdh) from thermophilic and mesophilic phototropic bacteria have been determined by x-ray crystallography and the corresponding structures compared. in contrast to the dimeric quaternary structure of most mdhs, these mdhs are tetramers and are structurally related to tetrameric malate dehydrogenases from archaea and to lactate dehydrogenases. the tetramers are dimers of dimers, where the structures of each subunit and the dimers are s ...	2002	12054817
microscopic examination of distribution and phenotypic properties of phylogenetically diverse chloroflexaceae-related bacteria in hot spring microbial mats.	we investigated the diversity, distribution, and phenotypes of uncultivated chloroflexaceae-related bacteria in photosynthetic microbial mats of an alkaline hot spring (mushroom spring, yellowstone national park). by applying a directed pcr approach, molecular cloning, and sequence analysis of 16s rrna genes, an unexpectedly large phylogenetic diversity among these bacteria was detected. oligonucleotide probes were designed to target 16s rrnas from organisms affiliated with the genus chloroflexu ...	2002	12200318
characterization of type 1851 organism isolated from activated sludge samples.	five orange pigmented filamentous strains of eikelboom's type 1851 were isolated from bulking activated sludge, and were examined for their phylogenetic lineage, morphology, and physiology. the analysis of 16s rdna sequence revealed that the isolates belong to chloroflexus subdivision in green non sulfur bacteria. they shared most common features with type 1851, but the result of gram stain was negative. furthermore, they showed polymorphic nature and gliding motility, which could not be seen in ...	2002	12216610
l-malyl-coenzyme a lyase/beta-methylmalyl-coenzyme a lyase from chloroflexus aurantiacus, a bifunctional enzyme involved in autotrophic co(2) fixation.	the 3-hydroxypropionate cycle is a bicyclic autotrophic co(2) fixation pathway in the phototrophic chloroflexus aurantiacus (bacteria), and a similar pathway is operating in autotrophic members of the sulfolobaceae (archaea). the proposed pathway involves in a first cycle the conversion of acetyl-coenzyme a (acetyl-coa) and two bicarbonates to l-malyl-coa via 3-hydroxypropionate and propionyl-coa; l-malyl-coa is cleaved by l-malyl-coa lyase into acetyl-coa and glyoxylate. in a second cycle, glyo ...	2002	12374834
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
optically detected magnetic resonance of intact membranes from chloroflexus aurantiacus. evidence for exciton interaction between the rc and the b808-866 complex.	optically detected magnetic resonance of chlorosome-containing membranes from the green filamentous bacterium chloroflexus aurantiacus has been performed both by fluorescence and absorption detection. triplet states localized in the chlorosomes and in the b808-866 complex have been characterized. after chemical reduction with ascorbate followed by illumination at 200 k, recombination triplet state localized in the primary donor becomes largely populated under illumination at low temperature whil ...	2002	16228500
determination of the topography and biometry of chlorosomes by atomic force microscopy.	isolated chlorosomes of several species of filamentous anoxygenic phototrophic bacteria (fapb) and green sulfur bacteria (gsb) were examined by atomic force microscopy (afm) to characterize their topography and biometry. chlorosomes of chloroflexus aurantiacus, chloronema sp., and chlorobium (chl.) tepidum exhibited a smooth surface, whereas those of chl. phaeobacteroides and chl. vibrioforme showed a rough one. the potential artifactual nature of the two types of surfaces, which may have arisen ...	2002	16228503
;every dogma has its day': a personal look at carbon metabolism in photosynthetic bacteria.	dogmas are unscientific. what is perhaps the greatest biological dogma of all time, the 'unity of biochemistry' is, in the main, still having its day. according to present knowledge, the exceptions to this dogma are mere details when seen in relation to the biosystem as a whole. nevertheless the exceptions are scientifically interesting and the understanding of them has led to a better comprehension of photosynthesis and ecology. until the discovery of (14)c, photosynthetic co(2) fixation was li ...	2003	16228573
evolutionary relationships among photosynthetic bacteria.	to understand the evolution of photosynthetic bacteria it is necessary to understand how the main groups within bacteria have evolved from a common ancestor, a critical issue that has not been resolved in the past. recent analysis of shared conserved inserts or deletions (indels) in protein sequences has provided a powerful means to resolve this long-standing problem in microbiology. based on a set of 25 indels in highly conserved and widely distributed proteins, all main groups within bacteria ...	2003	16228576
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
a comparative study of bchg from green photosynthetic bacteria.	the gene bchg, coding for bacteriochlorophyll a synthase from a variety of green sulfur bacteria and the filamentous anoxygenic phototrophic bacteria, chloroflexus aurantiacus, chloronema sp., and roseiflexus castenholzii hl08, was partially sequenced and compared. the deduced amino acid consensus sequences for green sulfur bacteria and green filamentous anoxygenic phototrophic bacteria were found to belong to the ubia enzyme family of polyprenyltransferases with the most similar sequences being ...	2003	12560989
a thin-film electrochemical study of the "blue" copper proteins, auracyanin a and auracyanin b, from the photosynthetic bacterium chloroflexus aurantiacus: the reduction potential as a function of ph.	the reversible formal potentials of auracyanin a and auracyanin b, two closely related "blue" copper proteins from the photosynthetic bacterium chloroflexus aurantiacus, have been determined by protein film voltammetry in the range 4<or=ph<or=9. at ph 7 in 0.1 m nacl, the values of for auracyanin a and auracyanin b are 205+/-7 mv and 215+/-7 mv, respectively, versus the standard hydrogen electrode. in both cases there is a smooth but non-sigmoidal change in from approximately 190 mv at ph 9 to a ...	2003	12589566
acryloyl-coa reductase from clostridium propionicum. an enzyme complex of propionyl-coa dehydrogenase and electron-transferring flavoprotein.	acryloyl-coa reductase from clostridium propionicum catalyses the irreversible nadh-dependent formation of propionyl-coa from acryloyl-coa. purification yielded a heterohexadecameric yellow-greenish enzyme complex [(alpha2betagamma)4; molecular mass 600 +/- 50 kda] composed of a propionyl-coa dehydrogenase (alpha2, 2 x 40 kda) and an electron-transferring flavoprotein (etf; beta, 38 kda; gamma, 29 kda). a flavin content (90% fad and 10% fmn) of 2.4 mol per alpha2betagamma subcomplex (149 kda) wa ...	2003	12603323
arsenite oxidase, an ancient bioenergetic enzyme.	operons coding for the enzyme arsenite oxidase have been detected in the genomes from archaea and bacteria by blast searches using the amino acid sequences of the respective enzyme characterized in two different beta-proteobacteria as templates. sequence analyses show that in all these species, arsenite oxidase is transported over the cytoplasmic membrane via the tat system and most probably remains membrane attached by an n-terminal transmembrane helix of the rieske subunit. the biochemical and ...	2003	12679550
coupling of nuclear wavepacket motion and charge separation in bacterial reaction centers.	the mechanism of the charge separation and stabilization of separated charges was studied using the femtosecond absorption spectroscopy. it was found that nuclear wavepacket motions on potential energy surface of the excited state of the primary electron donor p* leads to a coherent formation of the charge separated states p(+)b(a)(-), p(+)h(a)(-) and p(+)h(b)(-) (where b(a), h(b) and h(a) are the primary and secondary electron acceptors, respectively) in native, pheophytin-modified and mutant r ...	2003	12681478
[the structure and biogeochemical activity of the phototrophic communities from the bol'sherechenskii alkaline hot spring].	microbial communities growing in the bed of the alkaline, sulfide hot spring bol'sherechenskii (the baikal rift area) were studied over many years (1986-2001). the effluent water temperature ranged from 72 to 74 degrees c, ph was from 9.25 to 9.8, and sulfide content was from 12 to 13.4 mg/ml. simultaneous effects of several extreme factors restrict the spread of phototrophic microorganisms. visible microbial fouling appears with a decrease in the temperature to 62 degrees c and in the sulfide c ...	2003	12751248
auracyanin b structure in space group p6(5).	the structure of auracyanin b, a 'blue' copper protein produced by chloroflexus aurantiacus, has previously been solved and refined in the hexagonal space group p6(4)22 with a single molecule in the asymmetric unit. the protein has now been crystallized in space group p6(5), with unit-cell parameters a = b = 115.9, c = 108.2 a. in the new crystal form, the asymmetric unit contains four protein molecules. the structure has been solved by molecular replacement and refined at 1.9 a resolution. the ...	2003	12925783
isolation and characterization of the b798 light-harvesting baseplate from the chlorosomes of chloroflexus aurantiacus.	the b798 light-harvesting baseplate of the chlorosome antenna complex of the thermophilic, filamentous anoxygenic phototrophic bacterium chloroflexus aurantiacus has been isolated and characterized. isolation was performed by using a hexanol-detergent treatment of freeze-thawed chlorosomes. the isolated baseplate consists of bchl a, beta-carotene, and the 5.7 kda csma protein with a ratio of 1.0 csma protein/1.6 bchl a/4.2 beta-carotenes. the baseplate has characteristic absorbance at 798 nm as ...	2003	12939153
compound-specific isotopic fractionation patterns suggest different carbon metabolisms among chloroflexus-like bacteria in hot-spring microbial mats.	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.	2003	14532055
electrostatic interactions across the dimer-dimer interface contribute to the ph-dependent stability of a tetrameric malate dehydrogenase.	malate dehydrogenase (mdh) from the moderately thermophilic bacterium chloroflexus aurantiacus (camdh) is a tetrameric enzyme, while mdhs from mesophilic bacteria usually are dimers. using site-directed mutagenesis, we show here that a network of electrostatic interactions across the extra dimer-dimer interface in camdh is important for thermal stability and oligomeric integrity. stability effects of single point mutations (e25q, e25k, d56n, d56k) varied from -1.2 degrees c to -26.8 degrees c, a ...	2003	14572663
exciton theory for supramolecular chlorosomal aggregates: 1. aggregate size dependence of the linear spectra.	the interior of chlorosomes of green bacteria forms an unusual antenna system organized without proteins. the steady-spectra (absorption, circular dichroism, and linear dichroism) have been modeled using the frenkel hamiltonian for the large tubular aggregates of bacteriochlorophylls with geometries corresponding to those proposed for chloroflexus aurantiacus and chlorobium tepidum chlorosomes. for the cf. aurantiacus aggregates we apply a structure used previously (v. i. prokhorenko., d. b. ste ...	2003	14581217
characterization of the chlorosome antenna of the filamentous anoxygenic phototrophic bacterium chloronema sp. strain udg9001.	the absorption and fluorescence properties of chlorosomes of the filamentous anoxygenic phototrophic bacterium chloronema sp. strain udg9001 were analyzed. the chlorosome antenna of chloronema consists of bacteriochlorophyll (bchl) d and bchl c together with gamma-carotene as the main carotenoid. hplc analysis combined with apci lc-ms/ms showed that the chlorosomal bchls comprise a highly diverse array of homologues that differ in both the degree of alkylation of the macrocycle at c-8 and/or c-1 ...	2003	14610639
stabilization of a tetrameric malate dehydrogenase by introduction of a disulfide bridge at the dimer-dimer interface.	malate dehydrogenase (mdh) from the moderately thermophilic bacterium chloroflexus aurantiacus (camdh) is a tetrameric enzyme, while mdhs from mesophilic organisms usually are dimers. to investigate the potential contribution of the extra dimer-dimer interface in camdh with respect to thermal stability, we have engineered an intersubunit disulfide bridge designed to strengthen dimer-dimer interactions. the resulting mutant (t187c, containing two 187-187 disulfide bridges in the tetramer) showed ...	2003	14636605
phylogenetic and physiological characterization of a filamentous anoxygenic photoautotrophic bacterium ' candidatus chlorothrix halophila' gen. nov., sp. nov., recovered from hypersaline microbial mats.	we report the phylogenetic and physiological characterization of a mesophilic and halophilic member of the filamentous anoxygenic phototrophic (fap) bacteria, provisionally named ' candidatus chorothrix halophila' gen. nov. sp. nov., that has been maintained in a highly enriched culture in our laboratory for over a decade. phylogenetic analysis of small-subunit rna-encoding sequences places ' candidatus chlorothrix halophila' in a clade that includes cultivated members of the genera chloroflexus ...	2004	14655000
horizontal gene transfer from eukarya to bacteria and domain shuffling: the alpha-amylase model.	alpha-amylases are present in all kingdoms of the living world. despite strong conservation of the tertiary structure, only a few amino acids are conserved in interkingdom comparisons. animal alpha-amylases are characterized by several typical motifs and biochemical properties. a few cases of such alpha-amylases have been previously reported in some eubacterial species. we screened the bacterial genomes available in the sequence databases for new occurrences of animal-like alpha-amylases. three ...	2004	14704857
molybdenum-containing arsenite oxidase of the chemolithoautotrophic arsenite oxidizer nt-26.	the chemolithoautotroph nt-26 oxidizes arsenite to arsenate by using a periplasmic arsenite oxidase. purification and preliminary characterization of the enzyme revealed that it (i) contains two heterologous subunits, aroa (98 kda) and arob (14 kda); (ii) has a native molecular mass of 219 kda, suggesting an alpha2beta2 configuration; and (iii) contains two molybdenum and 9 or 10 iron atoms per alpha2beta2 unit. the genes that encode the enzyme have been cloned and sequenced. sequence analyses r ...	2004	14996791
the bchu gene of chlorobium tepidum encodes the c-20 methyltransferase in bacteriochlorophyll c biosynthesis.	bacteriochlorophylls (bchls) c and d, two of the major light-harvesting pigments in photosynthetic green sulfur bacteria, differ only by the presence of a methyl group at the c-20 methine bridge position in bchl c. a gene potentially encoding the c-20 methyltransferase, bchu, was identified by comparative analysis of the chlorobium tepidum and chloroflexus aurantiacus genome sequences. homologs of this gene were amplified and sequenced from chlorobium phaeobacteroides strain 1549, chlorobium vib ...	2004	15090495
[model of aggregation of pigments in the chlorosomal antenna of the green bacteria chloroflexus aurantiacus].	independent experimental and theoretical evaluation was performed for the adequacy of our previously proposed general molecular model of structural organization of light-harvesting pigments in chlorosomal bacteriochlorophyll (bchl) c/d/e-containing superantenna of different green bacteria. simultaneous measurement of hole burning in the optical spectra of chlorosomal bchl c and temperature dependence of steady-state fluorescence spectra of bchl c was accomplished in intact cells of photosyntheti ...	2004	15125238
[mechanism of charge separation and their stabilization in bacterial reaction centers].	the nuclear wavepacket formed by 20-fs excitation on the p* potential energy surface in native and mutant (ym210w and ym210l) reaction centers of rhodobacter (rb.) sphaeroides and chloroflexus (c.) aurantiacus rcs was found to be reversibly transferred to the p+ba- surface at 120, 380, and 640-fs delays (monitored by measurements of ba- absorption at 1020-1028 nm). the reaction centers of ym210w(l) mutant show the most simple pattern of fs oscillations with a period of 230 fs in stimulated emiss ...	2004	15129622
a cambialistic superoxide dismutase in the thermophilic photosynthetic bacterium chloroflexus aurantiacus.	superoxide dismutase from the thermophilic anoxygenic photosynthetic bacterium chloroflexus aurantiacus was cloned, purified, and characterized. this protein is in the manganese- and iron-containing family of superoxide dismutases and is able to use both manganese and iron catalytically. this appears to be the only soluble superoxide dismutase in c. aurantiacus. iron and manganese cofactors were identified by using electron paramagnetic resonance spectroscopy and were quantified by atomic absorp ...	2004	15150226
large improvement in the thermal stability of a tetrameric malate dehydrogenase by single point mutations at the dimer-dimer interface.	the stability of tetrameric malate dehydrogenase from the green phototrophic bacterium chloroflexus aurantiacus (camdh) is at least in part determined by electrostatic interactions at the dimer-dimer interface. since previous studies had indicated that the thermal stability of camdh becomes lower with increasing ph, attempts were made to increase the stability by removal of (excess) negative charge at the dimer-dimer interface. mutation of glu165 to gln or lys yielded a dramatic increase in ther ...	2004	15321717
conservation of functional domain structure in bicarbonate-regulated "soluble" adenylyl cyclases in bacteria and eukaryotes.	soluble adenylyl cyclase (sac) is an evolutionarily conserved bicarbonate sensor. in mammals, it is responsible for bicarbonate-induced, camp-dependent processes in sperm required for fertilization and postulated to be involved in other bicarbonate- and carbon dioxide-dependent functions throughout the body. among eukaryotes, sac-like cyclases have been detected in mammals and in the fungi dictyostelium; these enzymes display extensive similarity extending through two cyclase catalytic domains a ...	2004	15322879
seeing green bacteria in a new light: genomics-enabled studies of the photosynthetic apparatus in green sulfur bacteria and filamentous anoxygenic phototrophic bacteria.	based upon their photosynthetic nature and the presence of a unique light-harvesting antenna structure, the chlorosome, the photosynthetic green bacteria are defined as a distinctive group in the bacteria. however, members of the two taxa that comprise this group, the green sulfur bacteria (chlorobi) and the filamentous anoxygenic phototrophic bacteria ("chloroflexales"), are otherwise quite different, both physiologically and phylogenetically. this review summarizes how genome sequence informat ...	2004	15340781
biotransformation and dissolution of petroleum hydrocarbons in natural flowing seawater at low temperature.	the objective of this study was to establish methods for controlled studies of hydrocarbon depletion from thin oil films in cold natural seawater, and to determine biotransformation in relation to other essential depletion processes. mineral oil was immobilized on the surface of hydrophobic fluortex fabrics and used for studies of microbial biodegradation in an experimental seawater flow-through system at low temperatures (5.9-7.4 degrees c) during a test period of 42 days. the seawater was coll ...	2004	15523916
self-aggregation of synthetic zinc oxo-bacteriochlorins bearing substituents characteristic of chlorosomal chlorophylls.	we prepared novel zinc 8-ethyl-8-methyl-7-oxo- and 7-ethyl-7-methyl-8-oxo-bacteriochlorins 1 and 2 possessing substituents characteristic of chlorosomal chlorophylls, exclusively observed in extramembraneous light-harvesting antennas of photosynthetic green bacteria. the electronic absorption spectra of monomeric 1 and 2 in thf were obviously different: the q(y) maximum of the former was 724 and that of the latter was 683 nm. this observed spectral difference was clearly explained by theoretical ...	2005	15675838
structural and spectroscopic properties of a reaction center complex from the chlorosome-lacking filamentous anoxygenic phototrophic bacterium roseiflexus castenholzii.	the photochemical reaction center (rc) complex of roseiflexus castenholzii, which belongs to the filamentous anoxygenic phototrophic bacteria (green filamentous bacteria) but lacks chlorosomes, was isolated and characterized. the genes coding for the subunits of the rc and the light-harvesting proteins were also cloned and sequenced. the rc complex was composed of l, m, and cytochrome subunits. the cytochrome subunit showed a molecular mass of approximately 35 kda, contained hemes c, and functio ...	2005	15716441
reversible self-organization of semisynthetic zinc chlorins into well-defined rod antennae.		2005	15844109
pentaplot: a software tool for the illustration of genome mosaicism.	dekapentagonal maps depict the phylogenetic relationships of five genomes in a visually appealing diagram and can be viewed as an alternative to a single evolutionary consensus tree. in particular, the generated maps focus attention on those gene families that significantly deviate from the consensus or plurality phylogeny. pentaplot is a software tool that computes such dekapentagonal maps given an appropriate probability support matrix.	2005	15938752
diel variations in carbon metabolism by green nonsulfur-like bacteria in alkaline siliceous hot spring microbial mats from yellowstone national park.	green nonsulfur-like bacteria (gnslb) in hot spring microbial mats are thought to be mainly photoheterotrophic, using cyanobacterial metabolites as carbon sources. however, the stable carbon isotopic composition of typical chloroflexus and roseiflexus lipids suggests photoautotrophic metabolism of gnslb. one possible explanation for this apparent discrepancy might be that gnslb fix inorganic carbon only during certain times of the day. in order to study temporal variability in carbon metabolism ...	2005	16000812
new class of bacterial membrane oxidoreductases.	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 ca ...	2005	16042380
purification and characterization of the b808-866 light-harvesting complex from green filamentous bacterium chloroflexus aurantiacus.	the integral membrane light-harvesting complex b808-866 from the thermophilic green filamentous bacterium chloroflexus aurantiacus has been isolated and characterized. reversed-phase hplc analysis demonstrated that the number of bacteriochlorophyll (bchl) in the b808-866 antenna complex is 36 +/- 2 per reaction center. the main carotenoid type is gamma-carotene, and the molar ratio of bchl to carotenoid is 3:2. the steady-state absorption and fluorescence spectroscopy of the b808-866 complex are ...	2005	16172935
bacterial diversity in the rhizosphere of proteaceae species.	the cape floral kingdom is an area of unique plant biodiversity in south africa with exceptional concentrations of rare and endemic species and experiencing drastic habitat loss. here we present the first molecular study of the microbial diversity associated with the rhizosphere soil of endemic plants of the proteaceae family (leucospermum truncatulum and leucadendron xanthoconus). genomic dna was extracted from l. truncatulum rhizosphere soil, l. xanthoconus rhizosphere and non-rhizosphere soil ...	2005	16232290
assaying for the 3-hydroxypropionate cycle of carbon fixation.	the 3-hydroxypropionate cycle is a novel pathway for autotrophic co2 fixation, which has been demonstrated in the thermophilic phototrophic bacterium chloroflexus aurantiacus; a yet to be defined variant of this pathway occurs in autotrophic members of the sulfolobales (crenarchaeota). the 3-hydroxypropionate cycle consists of the conversion of acetyl-coa to succinyl-coa, via malonyl-coa, 3-hydroxypropionate, propionyl-coa, and methylmalonyl-coa. carboxylation of acetyl-coa and propionyl-coa by ...	2005	16260293
functional differences between galactolipids and glucolipids revealed in photosynthesis of higher plants.	galactolipids represent the most abundant lipid class in thylakoid membranes, where oxygenic photosynthesis is performed. the identification of galactolipids at specific sites within photosynthetic complexes by x-ray crystallography implies specific roles for galactolipids during photosynthetic electron transport. the preference for galactose and not for the more abundant sugar glucose in thylakoid lipids and their specific roles in photosynthesis are not understood. introduction of a bacterial ...	2006	16648262
[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
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
low-temperature fluorescence from single chlorosomes, photosynthetic antenna complexes of green filamentous and sulfur bacteria.	fluorescence spectra of single chlorosomes isolated from a green filamentous bacterium (chloroflexus (cfl.) aurantiacus) and a green sulfur bacterium (chlorobium (cb.) tepidum) were measured by using a confocal laser microscope at 13 k. chlorosomes were frozen either in a liquid solution (floating chlorosome) or on a quartz plate after being adsorbed (adsorbed chlorosome). fluorescence peak wavelengths were shorter for the adsorbed single chlorosomes than for the floating ones. single floating c ...	2006	16950839
properties of succinyl-coenzyme a:d-citramalate coenzyme a transferase and its role in the autotrophic 3-hydroxypropionate cycle of chloroflexus aurantiacus.	the phototrophic bacterium chloroflexus aurantiacus uses the 3-hydroxypropionate cycle for autotrophic co(2) fixation. this cycle starts with acetyl-coenzyme a (coa) and produces glyoxylate. glyoxylate is an unconventional cell carbon precursor that needs special enzymes for assimilation. glyoxylate is combined with propionyl-coa to beta-methylmalyl-coa, which is converted to citramalate. cell extracts catalyzed the succinyl-coa-dependent conversion of citramalate to acetyl-coa and pyruvate, the ...	2006	16952935
transmission electron microscopic study on supramolecular nanostructures of bacteriochlorophyll self-aggregates in chlorosomes of green photosynthetic bacteria.	supramolecular nanostructures of bacteriochlorophyll (bchl) self-aggregates in major light-harvesting complexes (chlorosomes) of green photosynthetic bacteria were successfully observed by freeze-fracture transmission electron microscope. rod-shaped nanostructures with approximately 10 nm in diameter could be visualized in three types of green sulfur bacteria (chlorobium). diameter of the rod-shaped nanostructures in chlorobium chlorosomes was independent of the molecular structures of their lig ...	2006	17027873