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Jörg Overmann - One of the best experts on this subject based on the ideXlab platform.
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eLS - Green Sulfur Bacteria
Bergey's Manual of Systematics of Archaea and Bacteria, 2015Co-Authors: Jörg OvermannAbstract:Introduction. The green sulfur bacteria are predominately aquatic bacteria that grow photosynthetically under anoxic conditions. Similar to Chromatiaceae (purple sulfur bacteria) and purple nonsulfur bacteria (Proteobacteria), the photosynthetic metabolism of green sulfur bacteria differs from that of Cyanobacteria, algae, and green plants in that water cannot serve as an electron-donating substrate and molecular oxygen is not generated. The external electron donors for photosynthetic CO2 assimilation have low redox potentials and comprise reduced sulfur compounds and molecular hydrogen. Green sulfur bacteria can be distinguished from the Chromatiaceae by their distinct bacteriochlorophylls (BChls), the presence of special light-harvesting structures, and their exclusively photolithotrophic metabolism. Chlorobi / “Chlorobia” / Subclass I “Chlorobiales” / Green Sulfur Bacteria / Green Sulfur Bacteria The mol% G + C of the DNA is: 47.8–58.1 (Bd). Type genus: Chlorobium Nadson 1906, 190. Keywords: Green Sulfur Bacteria; Chlorobium; “Chlorobiaceae”
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A new purple sulfur bacterium isolated from a littoral microbial mat, Thiorhodococcus drewsii sp. nov.
Archives of microbiology, 2003Co-Authors: Annette Zaar, Georg Fuchs, Jochen R. Golecki, Jörg OvermannAbstract:A new strain of purple sulfur bacterium was isolated from a marine microbial mat sampled in Great Sippewissett Salt Marsh at the Atlantic coast (Woods Hole, Mass., USA). Single cells of strain AZ1 were coccus-shaped, highly motile by means of a single flagellum, and did not contain gas vesicles. Intracellular membranes were of the vesicular type. However, additional concentric membrane structures were present. The photosynthetic pigments were bacteriochlorophyll a and carotenoids of the normal spirilloxanthin series, with rhodopin as the dominant carotenoid. Hydrogen sulfide (up to 11 mM), sulfur, thiosulfate, and molecular hydrogen were used as electron donors during anaerobic phototrophic growth. During growth on sulfide, elemental sulfur globules were transiently stored inside the cells. Strain AZ1 is much more versatile than most other Chromatiaceae with respect to electron donor and organic substrates. In the presence of CO2, it is capable of assimilating C1–C5 fatty acids, alcohols, and intermediates of the tricarboxylic acid cycle. Strain AZ1 could also grow photoorganotrophically with acetate as the sole photosynthetic electron donor. Chemotrophic growth in the dark under microoxic conditions was not detected. Optimum growth occurred at pH 6.5–6.7, 30–35 °C, ≥50 µmol quanta m−2 s−1, and 2.4–2.6% NaCl. The DNA base composition was 64.5 mol% G+C. Comparative sequence analysis of the 16S rRNA gene confirmed that the isolate is a member of the family Chromatiaceae. Sequence similarity to the most closely related species, Thiorhodococcus minor DSMZ 11518T, was 97.8%; however, the value for DNA-DNA hybridization between both strains was only 20%. Because of the low genetic similarity and since strain AZ1 physiologically differs considerably from all other members of the Chromatiaceae, including Trc. minor, the new isolate is described as a new species of the genus Thiorhodococcus, Thiorhodococcus drewsii sp. nov.
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Specific detection of different phylogenetic groups of chemocline bacteria based on PCR and denaturing gradient gel electrophoresis of 16S rRNA gene fragments.
Archives of microbiology, 1999Co-Authors: Jörg Overmann, Marco J. L. Coolen, Christian TuschakAbstract:Specific amplification of 16S rRNA gene fragments in combination with denaturing gradient gel electrophoresis (DGGE) was used to generate fingerprints of Chromatiaceae, green sulfur bacteria, Desulfovibrionaceae, and β-Proteobacteria. Sequencing of the gene fragments confirmed that each primer pair was highly specific for the respective phylogenetic group. Applying the new primer sets, the bacterial diversity in the chemoclines of a eutrophic freshwater lake, a saline meromictic lake, and a laminated marine sediment was investigated. Compared to a conventional bacterial primer pair, a higher number of discrete DGGE bands was generated using our specific primer pairs. With one exception, all 15 bands tested yielded reliable 16S rRNA gene sequences. The highest diversity was found within the chemocline microbial community of the eutrophic freshwater lake. Sequence comparison revealed that the six sequences of Chromatiaceae and green sulfur bacteria detected in this habitat all represent distinct and previously unknown phylotypes. The lowest diversity of phylotypes was detected in the chemocline of the meromictic saline lake, which yielded only one sequence each of the Chromatiaceae, β-2-Proteobacteria, and Desulfovibrionaceae, and no sequences of green sulfur bacteria. The newly developed primer sets are useful for the detection of previously unknown phylotypes, for the comparison of the microbial diversity between different natural habitats, and especially for the rapid monitoring of enrichments of unknown bacterial species.
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Analysis of Subfossil Molecular Remains of Purple Sulfur Bacteria in a Lake Sediment
Applied and environmental microbiology, 1998Co-Authors: Marco J. L. Coolen, Jörg OvermannAbstract:Molecular remains of purple sulfur bacteria (Chromatiaceae) were detected in Holocene sediment layers of a meromictic salt lake (Mahoney Lake, British Columbia, Canada). The carotenoid okenone and bacteriophaeophytin a were present in sediments up to 11,000 years old. Okenone is specific for only a few species of Chromatiaceae, including Amoebobacter purpureus, which presently predominates in the chemocline bacterial community of the lake. With a primer set specific for Chromatiaceae in combination with denaturing gradient gel electrophoresis, 16S rRNA gene sequences of four different Chromatiaceae species were retrieved from different depths of the sediment. One of the sequences, which originated from a 9,100-year-old sample, was 99.2% identical to the 16S rRNA gene sequence of A. purpureus ML1 isolated from the chemocline. Employing primers specific for A. purpureus ML1 and dot blot hybridization of the PCR products, the detection limit for A. purpureus ML1 DNA could be lowered to 0.004% of the total community DNA. With this approach the DNA of the isolate was detected in 7 of 10 sediment layers, indicating that A. purpureus ML1 constituted at least a part of the ancient purple sulfur bacterial community. The concentrations of A. purpureus DNA and okenone in the sediment were not correlated, and the ratio of DNA to okenone was much lower in the subfossil sediment layers (2.7 · 10−6) than in intact cells (1.4). This indicates that degradation rates are significantly higher for genomic DNA than for hydrocarbon cell constituents, even under anoxic conditions and at the very high sulfide concentrations present in Mahoney Lake.
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Fossil carotenoids and paleolimnology of meromictic Mahoney Lake, British Columbia, Canada
Aquatic Sciences, 1993Co-Authors: Jörg Overmann, Ken J. Hall, Gerhard Sandmann, Tom G. NorthcoteAbstract:Vertical distribution of fossil carotenoids in a sediment core from meromictic Mahoney Lake was studied. Besides okenone and demethylated okenone, lutein and zeaxanthin and β -carotene isomers were identified. No carotenoids typical for purple nonsulfur or green sulfur bacteria were detected. The ratio of zeaxanthin to lutein (above 1:1 in all samples) indicates a dominance of cyanobacteria over green algae in the phytoplankton assemblages of the past. Okenone, which is found exclusively in Chromatiaceae, was the dominating carotenoid in all sediment zones. The oldest sediment layers containing okenone were deposited 11 000 years ago. Between 9000 and 7000 and since 3000 years b.p., Chromatiaceae reached a considerable biomass in the lake. Vertical changes in okenone concentration were not related to changes of paleotemperatures. In contrast, okenone concentrations decreased during periods of volcanic ash input. During most of the lake history, however, mean okenone concentrations were positively correlated with sedimentation rates. This indicates that vertical changes of okenone concentration in the sediment reflect past changes of purple sulfur bacterial biomass in the lake. According to these results, the past limnology of Mahoney Lake resembled that of the present with a sulfide-containing monimolimnion and a well-developed population of okenone-bearing purple sulfur bacteria.
Ricardo Guerrero - One of the best experts on this subject based on the ideXlab platform.
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A heterotrophic bacterium inhibits growth of several species of the genus Chlorobium
Archives of Microbiology, 1997Co-Authors: Balbina Nogales, Ricardo Guerrero, Isabel EsteveAbstract:A gram-negative bacterium (designed as strain BF 9500) causing growth inhibition zones on cell lawns of the anoxygenic phototrophic bacterium Chlorobium limicola BF 8000 was isolated from Lake Ciso (Spain). Strain BF 9500, identified as Stenotrophomonas maltophilia, caused growth inhibition zones on cell lawns of several strains of C. limicola except C. limicola DSM 245. It also inhibited other Chlorobium species and several heterotrophic bacteria. However, it had no effect on the growth of the eleven strains of Chromatiaceae tested. Strain BF 9500 caused the lysis of C. limicola BF 8000, whose cells formed “ghosts”. To date, this is the first report of a bacterium causing the lysis of species of the genus Chlorobium.
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Distribution of predatory bacteria that attack Chromatiaceae in a sulfurous lake
Microbial Ecology, 1992Co-Authors: Núria Gaju, Isabel Esteve, Ricardo GuerreroAbstract:Predatory bacteria that attack Chromatiaceae (purple sulfur bacteria) recovered from Lake Cisó (a mostly anaerobic holomictic lake) have been studied over two annual cycles. During the mixing period the lake was completely anaerobic; both predator and prey populations were found along the water column, and even at the surface. Throughout the stratification period maximum Chromatiaceae occurred between a depth of 1 and 3 m depth. The maximum numbers of predators and prey (Chromatiaceae) also occurred in this range. A collapse took place in the lake during the second annual cycle in 1986. It brought about changes in the physicochemical parameters of the lake, thus altering the population dynamics. Nevertheless, during both cycles the number of predatory bacteria was maximum immediately below the depth at which the maximum number of prey bacteria occurred.
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Distribution of predatory bacteria that attack Chromatiaceae in a sulfurous lake.
Microbial ecology, 1992Co-Authors: Núria Gaju, Isabel Esteve, Ricardo GuerreroAbstract:Predatory bacteria that attack Chromatiaceae (purple sulfur bacteria) recovered from Lake Ciso (a mostly anaerobic holomictic lake) have been studied over two annual cycles. During the mixing period the lake was completely anaerobic; both predator and prey populations were found along the water column, and even at the surface. Throughout the stratification period maximum Chromatiaceae occurred between a depth of 1 and 3 m depth. The maximum numbers of predators and prey (Chromatiaceae) also occurred in this range.
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Comparison of techniques to determine the abundance of predatory bacteria attacking Chromatiaceae
FEMS Microbiology Letters, 1992Co-Authors: Isabel Esteve, Núria Gaju, Joan Mir, Ricardo GuerreroAbstract:This work quantifies the number of bacterial predators attacking the population of Chromatiaceae in the hypolimnion of Lake Estanya to assess the potential role of these microorganisms in controlling phototrophic bacterial populations. The abundance of predators was estimated from total counts of infected prey cells and by counting plaque-forming units. In spite of the large difference between both determinations, their variations with depth and time followed very similar patterns. During the summer, in the hypolimnion, and during the winter in the entire lake, up to 60% of the prey cells had potential predators attached. In comparison, plaque counts showed that viable predators represented less than 1% of the population of the prey. Our results demonstrated that predatory bacteria were far more abundant than indicated by the low viable counts obtained, suggesting that they play a more important role in controlling phototrophic bacterial populations than is currently assumed.
Re Summons - One of the best experts on this subject based on the ideXlab platform.
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A distinctive biomarker assemblage in an Infracambrian oil and source rock from western India: Molecular signatures of eukaryotic sterols and prokaryotic carotenoids
'Elsevier BV', 2017Co-Authors: Bhattacharya S, Dutta S, Re SummonsAbstract:Molecular fossils record aspects of Neoproterozoic-Early Cambrian palaeobiology in the Bikaner-Nagaur Basin, western India. Biomarker hydrocarbons from crude oils and sedimentary rock extracts belonging to the Marwar Supergroup, India, were analyzed using gas chromatography-mass spectrometry, including molecular specific metastable reaction monitoring (MRM) transitions. The distinctive biomarker assemblage indicates significant contribution from both eukaryotes and bacteria. The steranes record contributions from algae as well as demosponges. Dominance of C-29 sterane isomers signifies that green algae were important primary producers while detection of traces of dinosteranes suggests input from dinoflagellates or their ancestors. The high C-30 sterane ratio (24-isopropylcholestane/24-n-propylcholestane;similar to 5) indicates substantial proliferation of Demospongiae which are widely considered as basal metazoa. The community of algae and other taxa, including sponges which require oxygen, thrived in a thin oxygenated layer in the upper water column. However, the presence of an underlying euxinic water column is demonstrated by the presence of gammacerane, extremely low values of pristane/phytane (around 0.4) and carotenoids derived from both green (Chlorobi) and purple (Chromatiaceae) sulfur bacteria. Chlorobactane, isorenieratane and (beta-isorenieratane indicate both green-and brown-pigmented Chlorobi, whereas the detection of okenane and renierapurpurane are diagnostic for the Chromatiaceae. Paleorenieratane, a carotenoid pigment from an apparently 'extinct' Chlorobi taxon is present in high abundance particularly in the sedimentary rock extract. Excellent preservation of the biomarkers and an extremely mild thermal history is indicated by sterane and triter pane molecular ratios with preferences for biological stereoisomers. The entire biomarker assemblage is indicative of a restricted, salinity-stratified depositional environment possibly including the presence of extensive, anoxygenic microbial mats. Some of the observed characteristics mirror those of other coeval successions in Oman, Eastern Siberia and Australia but the particular combination of features appears to be unique to this setting. (C) 2016 Elsevier B.V. All rights reserved
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A distinctive biomarker assemblage in an Infracambrian oil and source rock from western India: Molecular signatures of eukaryotic sterols and prokaryotic carotenoids
Precambrian Research, 2017Co-Authors: Sharmila Bhattacharya, Suryendu Dutta, Re SummonsAbstract:Abstract Molecular fossils record aspects of Neoproterozoic-Early Cambrian palaeobiology in the Bikaner-Nagaur Basin, western India. Biomarker hydrocarbons from crude oils and sedimentary rock extracts belonging to the Marwar Supergroup, India, were analyzed using gas chromatography–mass spectrometry, including molecular specific metastable reaction monitoring (MRM) transitions. The distinctive biomarker assemblage indicates significant contribution from both eukaryotes and bacteria. The steranes record contributions from algae as well as demosponges. Dominance of C29 sterane isomers signifies that green algae were important primary producers while detection of traces of dinosteranes suggests input from dinoflagellates or their ancestors. The high C30 sterane ratio (24-isopropylcholestane/24-n-propylcholestane; ∼5) indicates substantial proliferation of Demospongiae which are widely considered as basal metazoa. The community of algae and other taxa, including sponges which require oxygen, thrived in a thin oxygenated layer in the upper water column. However, the presence of an underlying euxinic water column is demonstrated by the presence of gammacerane, extremely low values of pristane/phytane (around 0.4) and carotenoids derived from both green (Chlorobi) and purple (Chromatiaceae) sulfur bacteria. Chlorobactane, isorenieratane and β-isorenieratane indicate both green- and brown-pigmented Chlorobi, whereas the detection of okenane and renierapurpurane are diagnostic for the Chromatiaceae. Paleorenieratane, a carotenoid pigment from an apparently ‘extinct’ Chlorobi taxon is present in high abundance particularly in the sedimentary rock extract. Excellent preservation of the biomarkers and an extremely mild thermal history is indicated by sterane and triterpane molecular ratios with preferences for biological stereoisomers. The entire biomarker assemblage is indicative of a restricted, salinity-stratified depositional environment possibly including the presence of extensive, anoxygenic microbial mats. Some of the observed characteristics mirror those of other coeval successions in Oman, Eastern Siberia and Australia but the particular combination of features appears to be unique to this setting.
A. Christine Munk - One of the best experts on this subject based on the ideXlab platform.
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Complete genome sequence of Allochromatium vinosum DSM 180(T).
Standards in genomic sciences, 2011Co-Authors: Thomas Weissgerber, Renate Zigann, David Bruce, Yun-juan Chang, John C. Detter, Loren Hauser, Cynthia D. Jeffries, Miriam Land, Cliff Han, A. Christine MunkAbstract:Allochromatium vinosum formerly Chromatium vinosum is a mesophilic purple sulfur bacterium belonging to the family Chromatiaceae in the bacterial class Gammaproteobacteria. The genus Allochromatium contains currently five species. All members were isolated from freshwater, brackish water or marine habitats and are predominately obligate phototrophs. Here we describe the features of the organism, together with the complete genome sequence and annotation. This is the first completed genome sequence of a member of the Chromatiaceae within the purple sulfur bacteria thriving in globally occurring habitats. The 3,669,074 bp genome with its 3,302 protein-coding and 64 RNA genes was sequenced within the Joint Genome Institute Community Sequencing Program.
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Complete genome sequence of Allochromatium vinosum DSM 180^T
Standards in Genomic Sciences, 2011Co-Authors: Thomas Weissgerber, Renate Zigann, David Bruce, Yun-juan Chang, John C. Detter, Loren Hauser, Cynthia D. Jeffries, Miriam Land, A. Christine Munk, Roxanne TapiaAbstract:Allochromatium vinosum formerly Chromatium vinosum is a mesophilic purple sulfur bacterium belonging to the family Chromatiaceae in the bacterial class Gammaproteobacteria . The genus Allochromatium contains currently five species. All members were isolated from freshwater, brackish water or marine habitats and are predominately obligate phototrophs. Here we describe the features of the organism, together with the complete genome sequence and annotation. This is the first completed genome sequence of a member of the Chromatiaceae within the purple sulfur bacteria thriving in globally occurring habitats. The 3,669,074 bp genome with its 3,302 protein-coding and 64 RNA genes was sequenced within the Joint Genome Institute Community Sequencing Program.
Isabel Esteve - One of the best experts on this subject based on the ideXlab platform.
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A heterotrophic bacterium inhibits growth of several species of the genus Chlorobium
Archives of Microbiology, 1997Co-Authors: Balbina Nogales, Ricardo Guerrero, Isabel EsteveAbstract:A gram-negative bacterium (designed as strain BF 9500) causing growth inhibition zones on cell lawns of the anoxygenic phototrophic bacterium Chlorobium limicola BF 8000 was isolated from Lake Ciso (Spain). Strain BF 9500, identified as Stenotrophomonas maltophilia, caused growth inhibition zones on cell lawns of several strains of C. limicola except C. limicola DSM 245. It also inhibited other Chlorobium species and several heterotrophic bacteria. However, it had no effect on the growth of the eleven strains of Chromatiaceae tested. Strain BF 9500 caused the lysis of C. limicola BF 8000, whose cells formed “ghosts”. To date, this is the first report of a bacterium causing the lysis of species of the genus Chlorobium.
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Distribution of predatory bacteria that attack Chromatiaceae in a sulfurous lake
Microbial Ecology, 1992Co-Authors: Núria Gaju, Isabel Esteve, Ricardo GuerreroAbstract:Predatory bacteria that attack Chromatiaceae (purple sulfur bacteria) recovered from Lake Cisó (a mostly anaerobic holomictic lake) have been studied over two annual cycles. During the mixing period the lake was completely anaerobic; both predator and prey populations were found along the water column, and even at the surface. Throughout the stratification period maximum Chromatiaceae occurred between a depth of 1 and 3 m depth. The maximum numbers of predators and prey (Chromatiaceae) also occurred in this range. A collapse took place in the lake during the second annual cycle in 1986. It brought about changes in the physicochemical parameters of the lake, thus altering the population dynamics. Nevertheless, during both cycles the number of predatory bacteria was maximum immediately below the depth at which the maximum number of prey bacteria occurred.
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Distribution of predatory bacteria that attack Chromatiaceae in a sulfurous lake.
Microbial ecology, 1992Co-Authors: Núria Gaju, Isabel Esteve, Ricardo GuerreroAbstract:Predatory bacteria that attack Chromatiaceae (purple sulfur bacteria) recovered from Lake Ciso (a mostly anaerobic holomictic lake) have been studied over two annual cycles. During the mixing period the lake was completely anaerobic; both predator and prey populations were found along the water column, and even at the surface. Throughout the stratification period maximum Chromatiaceae occurred between a depth of 1 and 3 m depth. The maximum numbers of predators and prey (Chromatiaceae) also occurred in this range.
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Comparison of techniques to determine the abundance of predatory bacteria attacking Chromatiaceae
FEMS Microbiology Letters, 1992Co-Authors: Isabel Esteve, Núria Gaju, Joan Mir, Ricardo GuerreroAbstract:This work quantifies the number of bacterial predators attacking the population of Chromatiaceae in the hypolimnion of Lake Estanya to assess the potential role of these microorganisms in controlling phototrophic bacterial populations. The abundance of predators was estimated from total counts of infected prey cells and by counting plaque-forming units. In spite of the large difference between both determinations, their variations with depth and time followed very similar patterns. During the summer, in the hypolimnion, and during the winter in the entire lake, up to 60% of the prey cells had potential predators attached. In comparison, plaque counts showed that viable predators represented less than 1% of the population of the prey. Our results demonstrated that predatory bacteria were far more abundant than indicated by the low viable counts obtained, suggesting that they play a more important role in controlling phototrophic bacterial populations than is currently assumed.