59 results on '"Pimenov, N. V."'
Search Results
2. Analysis of chitinase diversity in the Baltic Sea bottom sediments.
- Author
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Teplyuk AV, Samarov NI, Korzhenkov AA, Ul’yanova MO, Goeva MA, Kublanov IV, Kanapatskii TA, Pimenov NV, and Toshchakov SV
- Subjects
- Oceans and Seas, Chitinases genetics, Metagenome
- Published
- 2017
3. Structure and Seasonal Trophodynamics of Picophytoplankton in Sevastopol Bay and Adjacent Waters (the Black Sea).
- Author
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Mukhanovi VS, Rylkova OA, Churiloval TY, Sakhon EG, and Pimenov NV
- Subjects
- Bacterial Load, Bays, Biomass, Black Sea, Cell Count, Ecosystem, Phytoplankton classification, Phytoplankton metabolism, Seasons, Synechococcus metabolism, Water Pollution analysis, Eutrophication physiology, Phytoplankton growth & development, Synechococcus growth & development
- Abstract
Abundance and seasonal trophodynamics. (specific growth rate, daily production, and grazing mortality) of the major picophytoplankton components, Synechococcus cyanobacteria (Syn) and picoeukary- otes (Pico-E), were studied at three stations in Sevastopol Bay and adjacent coastal waters (the Black Sea) in 2014 by flow cytometry and the dilution method. Pico- E abundance was shown to increase along the nutrient and pollution gradient from the coastal waters outside the bay (annual average of 7.3 ± 5.4 x 103 cells mL⁻¹) to the eastern corner of the bay (28.7 ± 11.4 x 103 cells mL⁻¹), while no relation was found between the water pollution status.and Syn abundance (9.9 ± 8.7 x 10³ cells mL⁻¹, at all the stations, n=27). Matter flows through the communities (daily production for Syn and Pico-E 0-16.6 and 0-19.3 μg C L- day⁻¹, respec- tively; grazing mortality for Syn and PicoE 0-3.6 and 0-21.2 μg C L⁻¹ day⁻¹, respectively) were comparable to or even exceeded their biomass stocks (<0.05-6.8 and 0.9-26.5 μg C L- for Syn and PicoE, respectively), indicating high biomass turnover rates. The highest flow-to-stock ratio (up to 6 for Syn) and,a significant imbalance between daily production (P) and grazing mortality (G) were observed in the most polluted and eu- trophicated waters of the bay in spring (Pico-E: P/G <.1) and late summer (Syn: P/G > 1). Black River inflow to the bay was hypothesized to be among the mechanisms maintaining.this pronounced and long-term im- balance in the open system without any negative consequences for the picophytoplankton assemlages.
- Published
- 2016
4. Microbial Community Associated with Thioploca sp. Sheaths in the Area of the Posolski Bank Methane Seep, Southern Baikal.
- Author
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Chernitsyna SM, Khal'zov IA, Khanaeva TA, Morozov IV, Klimenkov IV, Pimenov NV, and Zemskayal TI
- Subjects
- Bacteroidetes classification, Bacteroidetes genetics, Bacteroidetes isolation & purification, Chloroflexi classification, Chloroflexi genetics, Chloroflexi isolation & purification, Crenarchaeota classification, Crenarchaeota genetics, Crenarchaeota isolation & purification, Ecosystem, Euryarchaeota classification, Euryarchaeota genetics, Euryarchaeota isolation & purification, Methane chemistry, Methane metabolism, Phylogeny, Planctomycetales classification, Planctomycetales genetics, Planctomycetales isolation & purification, Proteobacteria classification, Proteobacteria genetics, Proteobacteria isolation & purification, Siberia, Thiotrichaceae classification, Thiotrichaceae isolation & purification, Thiotrichaceae ultrastructure, Verrucomicrobia classification, Verrucomicrobia genetics, Verrucomicrobia isolation & purification, Groundwater microbiology, Lakes microbiology, Microbial Consortia physiology, RNA, Ribosomal, 16S genetics, Thiotrichaceae genetics
- Abstract
Bacterial mats formed by a colorless sulfur bacterium Thioploca sp. in the area of the Posolski Bank cold methane seep (southern Baikal) were -studied using electron microscopy and phylogenetic analysis. Morphologically the bacteria were identified as Thioploca ingrica.- Confocal microscopy of DAPI-stained samples revealed numerous rod-shaped, filamentous, and spiral microorganisms in the sheaths, as well as in- side and between the trichomes. Transmission electron microscopy revealed nonvacuolated bacteria and small cells-without cell envelopes within the sheath. Bacteria with pronounced intracytoplasmic membranes characteristic; of type I methanotrophs were observed at the outer side of the sheath. Based on analysis of the 16S rRNA gene sequences, the following phyla were idenified in the sheath community: Bacteroidetes, Nitro- spira, Chloroflexi, Planctomycetes, Verrucomicrobia,'y-, and 6-Proteobacteria, Euryarchaeota, Crenarchaeota, and Thaumarchaeota, as well as anammox bacteria. A hypothetical scheme of matter flows in the Lake Baikal bacterial mats was proposed based on the data on metabolism of the cultured homologues.
- Published
- 2016
5. A Novel Uncultured Bacterium of the Family Gallionellaceae: Description and Genome Reconstruction Based on the Metagenomic Analysis of Microbial Community in Acid Mine Drainage.
- Author
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Kadnikov VV, Ivasenko DA, Beletsky AV, Mardanov AV, Danilova EV, Pimenov NV, Karnachuk OV, and Ravin NV
- Subjects
- Acidithiobacillus classification, Acidithiobacillus genetics, Acidithiobacillus isolation & purification, Acidithiobacillus metabolism, Acidobacteria classification, Acidobacteria genetics, Acidobacteria isolation & purification, Acidobacteria metabolism, Adenosine Triphosphatases genetics, Adenosine Triphosphatases metabolism, Electron Transport Chain Complex Proteins genetics, Electron Transport Chain Complex Proteins metabolism, Electron Transport Complex III genetics, Electron Transport Complex III metabolism, Electron Transport Complex IV genetics, Electron Transport Complex IV metabolism, Gallionellaceae classification, Gallionellaceae isolation & purification, Gallionellaceae metabolism, Gene Expression, Humans, Hydrogen-Ion Concentration, Iron metabolism, Isoenzymes genetics, Isoenzymes metabolism, Metals chemistry, Metals metabolism, Mining, NADH Dehydrogenase genetics, NADH Dehydrogenase metabolism, Oxidation-Reduction, Oxidoreductases genetics, Oxidoreductases metabolism, Photosynthesis genetics, Phylogeny, Quinone Reductases genetics, Quinone Reductases metabolism, Siberia, Sulfate Adenylyltransferase genetics, Sulfate Adenylyltransferase metabolism, Thiobacillus classification, Thiobacillus genetics, Thiobacillus isolation & purification, Thiobacillus metabolism, Gallionellaceae genetics, Genome, Bacterial, Metagenome, Microbial Consortia genetics, RNA, Ribosomal, 16S genetics, Wastewater microbiology
- Abstract
Drainage waters at the metal mining areas often have low pH and high content of dissolved metals due to oxidation of sulfide minerals. Extreme conditions limit microbial diversity in- such ecosystems. A drainage water microbial community (6.5'C, pH 2.65) in an open pit at the Sherlovaya Gora polymetallic open-cast mine (Transbaikal region, Eastern Siberia, Russia) was studied using metagenomic techniques. Metagenome sequencing provided information for taxonomic and functional characterization of the micro- bial community. The majority of microorganisms belonged to a single uncultured lineage representing a new Betaproteobacteria species of the genus Gallionella. While no.acidophiles are known among the cultured members of the family Gallionellaceae, similar 16S rRNA gene sequences were detected in acid mine drain- ages. Bacteria ofthe genera Thiobacillus, Acidobacterium, Acidisphaera, and Acidithiobacillus,-which are com- mon in acid mine drainage environments, were the minor components of the community. Metagenomic data were -used to determine the almost complete (-3.4 Mb) composite genome of the new bacterial. lineage desig- nated Candidatus Gallionella acididurans ShG14-8. Genome analysis revealed that Fe(II) oxidation probably involved the cytochromes localized on the outer membrane of the cell. The electron transport chain included NADH dehydrogenase, a cytochrome bc1 complex, an alternative complex III, and cytochrome oxidases of the bd, cbb3, and bo3 types. Oxidation of reduced sulfur compounds probably involved the Sox system, sul- fide-quinone oxidoreductase, adenyl sulfate reductase, and sulfate adenyltransferase. The genes required for autotrophic carbon assimilation via the Calvin cycle were present, while no pathway for nitrogen fixation was revealed. High numbers of RND metal transporters and P type ATPases were probably responsible for resis- tance to heavy metals. The new microorganism was an aerobic chemolithoautotroph of the group of psychrotolerant iron- and sulfur-oxidizing acidophiles of the family Gallionellaceae, which are common in acid mine drainages.
- Published
- 2016
6. [Role of Anammox Bacteria in Removal of Nitrogen Compounds from Wastewater].
- Author
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Kallistovaa AY, Dorofeev AG, Nikolaev YA, Kozlov MN, Kevbrina MV, and Pimenov NV
- Subjects
- Ammonia metabolism, Bacteria, Anaerobic growth & development, Wastewater microbiology, Water Microbiology
- Abstract
The review deals with the unique microbial group responsible for anaerobic ammonium oxidation with nitrite (anammox), and with the role of this process in development of the biotechnology for removal of nitrogen compounds from wastewater. The history of the study of this process is briefly related. Up-to date knowledge on the intracellular organization, energy metabolism, growth stoichiometry, and physiology of anammox bacteria is described, and the main methods for cultivation of these microorganisms are characterized. Special attention is paid to the problems associated with practical application of anammox bacteria, which result from their extremely slow growth, the absence of pure cultures, and the interaction with other microbial groups.
- Published
- 2016
7. [Microbial Processes and Genesis of Methane Gas Jets in the Coastal Areas of the Crimea Peninsula].
- Author
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Malakhova TV, Kanapatskii TA, Egorov VN, Malakhova LV, Artemov YG, Evtushenko DB, Gulin SB, and Pimenov NV
- Subjects
- Black Sea, Russia, Biofilms, Methane metabolism, Microbial Consortia physiology, Water Microbiology
- Abstract
Hydroasoustic techniques were used for detection and mapping of gas jet areas in the coastal regions of the Crimean peninsula. Gas seep areas in the bays Laspi, Khersones, and Kazach'ya were chosen for detailed microbiological investigation. The first type of gas jets, observed in the Laspi Bay, was probably associated with discarge of deep thermogenic methane along the faults. Methane isotopic composition was char- acterized by Δ13C of -35.3 degrees. While elevated rates of aerobic methane oxidation were revealed in the sandy sediments adjacent to the methane release site, no evidence of bacterial mats was found. The second type of gas emission, observed in the Khersones Bay, was accompanied by formation of bacterial biofilms of the "Thiodendron" microbial community type, predominated by filamentous, spirochete-like organisms, in the areas of gas seepage. The isotopic composition of methane was there considerably lower (-60.4 degrees), indicating a considerable contribution of modern microbial methane to the gas bubbles discharged in this bay. Activity of the third type of gas emission, the seeps of the Kazach'ya Bay, probably depended directly on modern microbial processes of organic matter degradation in the upper sediment layers. The rates of sulfate reduction and methanogenesis were 260 and 34 μmol dm(-3) day(-1), respectively. Our results indicate different mechanisms responsible for formation of methane jets in the Laspi Bay and in the coastal areas of the Heracles Peninsula, where the bays Kazach'ya and Khersones are located.
- Published
- 2015
8. [An Acidophilic Desulfosporosinus Isolated from the Oxidized Mining Wastes in the Transbaikal Area].
- Author
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Karnachuk OV, Kurganskaya IA, Avakyan MR, Frank YA, Ikkert OP, Filenko RA, Danilovac EV, and Pimenov NV
- Subjects
- Clostridium classification, Clostridium drug effects, Clostridium genetics, Copper chemistry, Copper metabolism, Copper pharmacology, Humans, Hydrogen-Ion Concentration, Microbial Consortia genetics, Oxidation-Reduction, Phylogeny, Siberia, Sulfates chemistry, Sulfates metabolism, Waste Products, Clostridium metabolism, Mining, RNA, Ribosomal, 16S genetics
- Abstract
Dissimilatory sulfate reduction plays an important role in removal of dissolved metals from acidic mine waters. Although this process was convincingly shown to occur in acidic waste of metal recovery, few isolates of acid-tolerant sulfate rducers are known. We isolated a new acidophilic sulfidogen, strain BG, from the oxidized acidic waste of the Bom-Gorkhon tungsten deposit, Transbaikalia, Russia. Phylogenetic analysis of its 16S rRNA gene sequence made it possible to identify it as a member of the genus Desulfosporosinus. Unlike other known acidophilic sulfate reducers of this genus, strain BG was tolerant to high copper concentrations (up to 5 g/L), could grow on organic acids at low ambient pH, and formed crystalline copper sulfides (covellite and chalcopyrite). Molecular analysis of the phenotypes predominating in oxidized waste and in enrichment cultures confirmed the presence of various Desulfosporosinus strains.
- Published
- 2015
9. [Active Sulfate Reduction in Acidic Sediments of Gold Mine Tailings].
- Author
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Pimenov NV, Ivasenko DA, Gerasimchuk AL, Zakharova EE, Mardanov AV, and Karnachuk OV
- Subjects
- Desulfovibrio isolation & purification, Desulfovibrio physiology, Gold isolation & purification, Humans, Hydrogen-Ion Concentration, Oxidation-Reduction, Desulfovibrio chemistry, Mining, Sulfates chemistry, Water Microbiology
- Published
- 2015
10. [Sulfate-Reducing Bacterial Communities in the Water Column of the Gdansk Deep (Baltic Sea)].
- Author
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Korneeva VA, Pimenov NV, Krek AV, Tourova TP, and Bryukhanov AL
- Subjects
- Atlantic Ocean, Colony Count, Microbial, Deltaproteobacteria genetics, Deltaproteobacteria metabolism, Desulfotomaculum genetics, Desulfotomaculum metabolism, Desulfovibrio genetics, Desulfovibrio metabolism, Genes, rRNA, Hydrogen Sulfide metabolism, Microbial Consortia genetics, Oxidation-Reduction, Phylogeny, Polymerase Chain Reaction, RNA, Ribosomal, 16S genetics, Sulfur-Reducing Bacteria genetics, Sulfur-Reducing Bacteria metabolism, Deltaproteobacteria classification, Desulfotomaculum classification, Desulfovibrio classification, Genes, Bacterial, Sulfur-Reducing Bacteria classification, Water Microbiology
- Abstract
Biodiversity of sulfate-reducing bacterial communities in the water column of the Gdansk Deep, Baltic Sea, where H2S had been detected in near-bottom layers, was analyzed by PCR with primers for the 16S rRNA genes of six major phylogenetic subgroups of sulfate-reducing bacteria (SRB). Using denaturing gradient gel electrophoresis followed by sequencing, the nucleotide sequences of reamplified dsrB gene fragments from investigated water samples were determined. For the first time the presence of nucleotide sequences of the dsrB gene was detected by PCR in the water samples from all hydrochemical layers, including subsurface oxic waters. The presence of the 16S rRNA genes of representatives of Desulfotomaculum, Desulfococcus-Desulfonema-Desulfosarcina, and Desulfovibrio-Desulfomicrobium SRB subgroups was also revealed throughout the water column of the Gdansk Deep. Analysis of translated amino acid sequences encoded by the dsrB gene demonstrated the highest homology with the relevant sequences of uncultured SRB from various marine habitats.
- Published
- 2015
11. [Candidatus "Jettenia moscovienalis" sp. nov., a New Species of Bacteria Carrying out Anaerobic Ammonium Oxidation].
- Author
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Nikolaev A, Kozlov MN, Kevbrina MV, Dorofeev AG, Pimenov NV, Kallistova AY, Grachev VA, Kazakova EA, Zharkov AV, Kuznetsov BB, Patutina EO, and Bumazhkin BK
- Subjects
- Anaerobiosis, Hydrogen-Ion Concentration, Intracellular Membranes ultrastructure, Nitrites metabolism, Oxidation-Reduction, Phylogeny, Planctomycetales isolation & purification, Planctomycetales ultrastructure, RNA, Ribosomal, 16S genetics, Wastewater microbiology, Ammonia metabolism, Genes, rRNA, Planctomycetales classification, Planctomycetales metabolism, Water Microbiology
- Abstract
A new species of bacteria oxidizing ammonium with nitrite under anoxic conditions was isolated from the activated sludge of a semi-industrial bioreactor treating digested sludge of the Kuryanovo wastewater treatment plant (Moscow, Russia). Physiological, morphological, and molecular genetic characterization of the isolate was carried out. The cells were ovoid (-0.5 x 0.8 μm), with the intracellular membrane structures characteristic of anammox bacteria (anammoxosome and paryphoplasm); unlike other anammox bacteria, it possessed extensive intracellular membrane structures located in layers parallel to the cytoplasmic membrane, but never close to the anammoxosome. The cells formed aggregates 5-28 μm in diameter and readily attached to solid surfaces. The cells were morphologically labile, easily plasmolyzed, and lost their content. Doubling time was 28 days, μ(max) = 0.025 day(-1); optimal temperature and pH for growth were 20-45 degrees C and 8.0, respectively. Phylogenetic analysis of the 16S rRNA gene sequences suggested its classification as a new species of the candidate genus Jettenia (order Planctomycetales). The name Candidatus "Jettenia moscovienalis" sp. nov. was proposed for the new bacterium.
- Published
- 2015
12. [Detection of methane in the water column at gas and oil seep sites in central and southern Lake Baikal].
- Author
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Zakharenko AS, Pimenov NV, Ivanov VG, and Zemskaia TI
- Subjects
- Bacterial Typing Techniques, In Situ Hybridization, Fluorescence, Lakes chemistry, Methane chemistry, Methane metabolism, Methylobacteriaceae classification, Oil and Gas Fields chemistry, Oxidation-Reduction, Siberia, DNA, Bacterial analysis, Lakes microbiology, Methylobacteriaceae genetics, Oil and Gas Fields microbiology, Water Microbiology
- Abstract
Microbiological and biogeochemical investigation of the water column of oligotrophic Lake Baikal at the sites of the K2 and Bolshoy mud volcanoes and the Gorevoy Utes oil seep was carried out in July 2013. Total microbial numbers (TMN), cell numbers of type I and type II methanotrophs, and methane concentrations were measured; the rate of methane oxidation was determined. Methane concentrations in Lake Baikal water column varied from 0.09 to 1 μL/L, while methane oxidation rates varied from 0.007 to 0.9 nL/(L day). The highest rates of methane oxidation were revealed in the near-bottom water horizons at the sites of the Bolshoy mud volcano and the Gorevoy Utes oil seep. These were the sites where the most pronounced anomalies in methane concentration were also detected. TMN varied from 0.123 x 10(6) to 1.64 x 10(6) cells/mL. Methanotrophic bacteria were revealed in the water column at all sites, their abundance did not always correlate with methane concentrationsand the rates of methane oxidation. Methanotrophs constituted not more than 1.63% of the total microbial number, with their highest abundance in the upper 200 m of the water column.
- Published
- 2015
13. [Production of gaseous hydrocarbons by microbial communities of Lake Baikal bottom sediments].
- Author
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Pavlova ON, Bukin SV, Lomakina AV, Kalmychkov GV, Ivanov VG, Morozov IV, Pogodaeva TV, Pimenov NV, and Zemskaya TI
- Subjects
- Archaea genetics, Carbon Dioxide metabolism, Crenarchaeota genetics, Crenarchaeota isolation & purification, Crenarchaeota metabolism, Ethane metabolism, Euryarchaeota genetics, Euryarchaeota isolation & purification, Euryarchaeota metabolism, Gene Library, Lakes, Methane metabolism, Microbial Consortia, Molecular Sequence Data, RNA, Ribosomal, 16S, Siberia, Archaea metabolism, Geologic Sediments microbiology, Hydrocarbons metabolism, Phylogeny
- Abstract
Production of gaseous hydrocarbons by the microbial community of the Posolsky Bank methane seep bottom sediments (Southern Baikal) was studied at 4°C. Formation of both methane and a heavier gas- eous hydrocarbon, ethane, was detected in enrichment cultures. The highest methane concentrations (6.15 and 4.51 mmol L(-1)) were revealed in enrichments from the sediments from 55-cm depth incubated with-so- dium acetate and H2/CO2 gas mixture, respectively. A decrease in activity of aceticlastic methanogensand a decrease in methane concentration produced by hydrogenotrophic archaea occurred with depth. The highest concentration of ethane was revealed in enrichments from the microbial community of the layer close to gas hydrates (75 cm) incubated with CO2 as a substrate. According to analysis of the 16S rRNA gene fragments from the clone library, these enrichments were found to contain members of the phylum Crenarchaeota form- ing a separate cluster with members of the class Thermoprotei. The phylum Euryarchaeota was represented by nucleotide sequences of the organisms homologous to members of the orders Methanococcales, Methanosa- rcinales, and Thermoplasmatales.
- Published
- 2014
14. [Microbial composition of the activated sludges of the Moscow wastewater treatment plants].
- Author
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Kallistova AIu, Pimenov NV, Kozlov MN, Nikolaev IuA, Dorofeev AG, Aseeva VG, Grachev VA, Men'ko EV, Berestovskaia IuIu, Nozhevnikova AN, and Kevbrina MV
- Subjects
- Moscow, Bacteria classification, Bacteria isolation & purification, Bacteria metabolism, Sewage microbiology, Wastewater microbiology, Water Microbiology, Water Purification
- Abstract
The contribution of the major technologically important microbial groups (ammonium- and nitrite-oxidizing, phosphate-accumulating, foam-inducing, and anammox bacteria, as well as planctomycetes and methanogenic archaea) was characterized for the aeration tanks of the Moscow wastewater treatment facilities. FISH investigation revealed that aerobic sludges were eubacterial communities; the metabolically active archaea contributed insignificantly. Stage II nitrifying microorganisms and planctomycetes were significant constituents of the bacterial component of activated sludge, with Nitrobacter spp. being the dominant nitrifier. No metabolically active anammox bacteria were revealed in the sludge from aeration tanks. The sludge from the aeration tanks using different wastewater treatment technologies were found to differ in characteristics. Abundance of the nitrifying and phosphate-accumulating bacteria in the sludges generally correlated with microbial activity, in microcosms and with efficiency of nitrogen and phosphorus removal from wastewater. The highest microbial numbers and activity were found in the sludges of the tanks operating according to the technologies developed in the universities of Hanover and Cape Town. The activated sludge from the Novokur yanovo facilities, where abundant growth of filamentous bacteria resulted in foam formation, exhibited the lowest activity The group of foaming bacteria included Gordonia spp. and Acinetobacter spp., utilizing petroleum and motor oils, Sphaerotilus spp. utilizing unsaturated fatty acids, and Candidatus 'Microthrix parvicella'. Thus, the data on abundance and composition of metabolically active microorganisms obtained by FISH may be used for the technological control of wastewater treatment.
- Published
- 2014
15. [Activity and structure of the sulfate-reducing bacterial community in the sediments of the southern part of Lake Baikal].
- Author
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Pimenov NV, Zakharova EE, Briukhanov AL, Korneeva VA, Kuznetsov BB, Turova TP, Pogodaeva TV, Kalmychkov GV, and Zemskaia TI
- Subjects
- DNA, Bacterial genetics, Molecular Sequence Data, Phylogeny, RNA, Ribosomal, 16S, Siberia, Sulfur-Reducing Bacteria genetics, Water Microbiology, Geologic Sediments microbiology, Lakes microbiology, Microbial Consortia physiology, Sulfur-Reducing Bacteria isolation & purification
- Abstract
The rates of sulfate reduction (SR) and the diversity of sulfate-reducing bacteria (SRB) were studied in the sediments of the Posol'skaya banka elevation in the southern part of Lake Baikal. SR rates varied from 1.2 to 1641 nmol/(dm3 day), with high rates (> 600 nmol/(dm3 day)) observed at both deep-water stations and in subsurface silts. Integral SR rates calculated for the uppermost 50 cm of the sediments were higher for gas-saturated and gas hydrate-bearing sediments than in those with low methane content. Enrichment SRB cultures were obtained in Widdel medium for freshwater SRB. Analysis of the 16S rRNA gene fragments from clone libraries obtained from the enrichments revealed the presence of SRB belonged to Desulfosporosinus genus, with D. lacus as the most closely related member (capable of sulfate, sulfite, and thiosulfate reduction), as well as members of the order Clostridiales.
- Published
- 2014
16. [Anoxygenic phototrophic bacteria of the Kislo-Sladkoe Stratified Lake (White Sea, Kandalaksha Bay)].
- Author
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Lunina ON, Savvichev AS, Kuznetsov BB, Pimenov NV, and Gorlenko VM
- Subjects
- Chlorobium genetics, Chlorobium isolation & purification, Chromatiaceae genetics, Chromatiaceae isolation & purification, Lakes chemistry, Phototrophic Processes, Proteobacteria genetics, Proteobacteria isolation & purification, RNA, Ribosomal, 16S, Rhodospirillaceae genetics, Rhodospirillaceae isolation & purification, Russia, Water Microbiology, Lakes microbiology
- Abstract
The community of anoxygenic phototrophic bacteria (APB) in the water column of the Kislo-Sladkoe stratified lake recently isolated from the sea (White Sea, Kandalaksha Bay) was investigated in September 2010. The water of the sulfide-rich zone was greenish-brown due to intense development of green sulfur bacteria (GSB). Nine APB strains were isolated from the water samples: three belonging to GSB, five, to purple sulfur bacteria (PSB), and one, to purple nonsulfur bacteria (PNB). GSB predominated in the phototrophic community of the chemocline. Unexpectedly, two morphologically different green-colored GSB strains were found to be phylogenetically identical and related to the brown-colored @Chlorobium phaeovibrioides (99% similarity according to the 16S rRNA gene sequencing). Homology to the closest green-colored species (Chlorobium luteolum) was 98%. Two morphologically and physiologically similar PSB strains (TcrPS10 and AmPS10) had rounded cells containing okenonokenonee and gas vesicles. According to the 16S rRNA gene sequencing, these strains were most closely related (99%) to two different Thiocapsa species: Tca. marina (containing okenonokenonee and no gas vesicles) and Tca. rosea (containing spirilloxanthin and gas vesicles). The remaining isolates of purple bacteria were similar to the already described APB species.
- Published
- 2014
17. [Sulfate reduction and microbial processes of the methane cycle in the sediments of the Sevastopol bay].
- Author
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Pimenov NV, Egorov VN, Kanapatskiĭ TA, Malakhova TV, Artemov IuG, Sigalevich PA, and Malakhova LV
- Subjects
- Black Sea, Oxidation-Reduction, Methane metabolism, Sulfates metabolism, Water Microbiology
- Abstract
The rates of microbial processes of sulfate reduction and of the methane cycle were measured in the bottom sediments of the Sevastopol basin, where seeps of gaseous methane have been previously found. Typically for marine environments, sulfate reduction played the major role in the terminal phase of decomposition of organic matter (OM) in reduced sediments of this area. The rate of this process depended on the amount of available OM. The rate of methanogenesis in the sediments increased with depth, peaking in the subsurface horizons, where decreased sulfate concentration was detected in the pore water. The highest rates of sulfate-dependent anaerobic methane oxidation were found close to the methane-sulfate transition zone as is typical of most investigated marine sediments. The data on the carbon isotopic composition of gaseous methane from the seeps and dissolved CH4 from the bottom sediments, as well as on the rates of microbial methanogenesis and methane oxidation indicate that the activity of the methane seeps results from accumulation of biogenic methane in the cavities of the underlying geological structures with subsequent periodic release of methane bubbles into the water column.
- Published
- 2013
18. [Molecular biology detection of methanogenic archaea in oxidised water of Black sea].
- Author
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Korneeva VA, Briukhanov AL, and Pimenov NV
- Subjects
- Black Sea, Oxidation-Reduction, Euryarchaeota classification, Euryarchaeota genetics, Euryarchaeota isolation & purification, Water Microbiology
- Published
- 2013
19. [Sulfate reduction, methane formation and oxidation in the surface sediments in Vislinskiĭ and Kurshskiĭ Bay in the Baltic sea].
- Author
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Pimenov NV, Ul'ianova MO, Kanapatskiĭ TA, Mitskevich IN, Rusanov II, Sigalevich PA, Nemirovskaia IA, and Sivkov VV
- Subjects
- Oceans and Seas, Oxidation-Reduction, Russia, Geologic Sediments chemistry, Geologic Sediments microbiology, Methane metabolism, Seawater microbiology, Sulfates metabolism
- Published
- 2013
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20. [Bacterial sulfur-reducing community in the hydrogen sulfide-rich waters of the "Resort Ust-Kachka (Perm Region, Russia)].
- Author
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Pimenov NV, Kuranov GV, Briukhanov AL, Veslopolova EF, Koriukina IP, and Maslov IuN
- Subjects
- Bacterial Proteins classification, Bacterial Proteins metabolism, Cold Temperature, Health Resorts, Oxidoreductases Acting on Sulfur Group Donors classification, Oxidoreductases Acting on Sulfur Group Donors metabolism, Phylogeny, Polymerase Chain Reaction, RNA, Ribosomal, 16S classification, Russia, Sequence Analysis, DNA, Sulfur Radioisotopes, Sulfur-Reducing Bacteria classification, Sulfur-Reducing Bacteria isolation & purification, Sulfur-Reducing Bacteria metabolism, Bacterial Proteins genetics, Microbial Consortia physiology, Oxidoreductases Acting on Sulfur Group Donors genetics, RNA, Ribosomal, 16S genetics, Sulfur-Reducing Bacteria genetics
- Published
- 2012
21. [Psychrophilic sulfate reducing bacterium from aerobic Black Sea waters].
- Author
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Zakharova EE, Korneeva VA, Briukhanov AL, and Pimenov NV
- Subjects
- Aerobiosis physiology, Black Sea, Cold Temperature, Kinetics, Phylogeny, Sulfur-Reducing Bacteria genetics, Sulfur-Reducing Bacteria metabolism, Hydrogen Sulfide metabolism, Manganese metabolism, Oxygen metabolism, RNA, Ribosomal, 16S genetics, Sulfur-Reducing Bacteria isolation & purification
- Published
- 2012
22. [Bacterioplankton of Poland region of Baltic sea].
- Author
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Kudriavtseva EA, Savvichev AS, Aleksandrov SV, Kanapatskiĭ TA, and Pimenov NV
- Subjects
- Oceans and Seas, Poland, Bacteria metabolism, Biomass, Seasons, Water Microbiology
- Published
- 2012
23. [Sulfate reduction, formation and oxidation of methane in Holocene era sediments of the Vyborg Bay, Baltic Sea].
- Author
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Pimenov NV, Kanapatskiĭ TA, Sigalevich PA, Rusanov II, Veslopolova EF, Grigor'ev AG, and Zhamoĭda VA
- Subjects
- Carbon chemistry, Carbon metabolism, Carbon Cycle, Geologic Sediments chemistry, Hydrogen Sulfide metabolism, Oxidation-Reduction, Russia, Seawater chemistry, Sulfates chemistry, Sulfates metabolism, Sulfur chemistry, Sulfur metabolism, Geologic Sediments microbiology, Methane metabolism, Microbial Consortia physiology, Seawater microbiology, Water Microbiology
- Published
- 2012
24. [Investigation of the sulfate-reducing bacterial populations in the aerobic waters and in the chemocline zone of Black Sea by FISH].
- Author
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Briukhanov AL, Korneeva VA, Kanapatskiĭ TA, Zakharova EE, Men'ko EV, Rusanov II, and Pimenov NV
- Subjects
- Aerobiosis, In Situ Hybridization, Fluorescence, Oceans and Seas, Russia, Sulfur-Reducing Bacteria classification, Sulfur-Reducing Bacteria genetics, Seawater microbiology, Sulfur-Reducing Bacteria isolation & purification
- Published
- 2011
25. [Methanotrophic archaea detection using sequence analysis of methyl coenzyme M reductase A gene in pockmark sediments( Gdansk Basin, Baltic Sea) ].
- Author
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Merkel' AIu, Chernykh NA, Kanapatskiĭ TA, and Pimenov NV
- Subjects
- Archaea genetics, Archaea classification, Archaea isolation & purification, Geologic Sediments microbiology, Methane metabolism, Oxidoreductases genetics, Seawater microbiology
- Published
- 2010
26. [Microbial community of the pockmark sediments of the Gdansk Basin, the Baltic Sea ].
- Author
-
Shubenkova OV, Likhishvaĭ AV, Kanapatskiĭ TA, and Pimenov NV
- Subjects
- Archaea genetics, Archaea isolation & purification, Bacteria genetics, Bacteria isolation & purification, Phylogeny, Poland, RNA, Ribosomal, 16S genetics, Archaea classification, Bacteria classification, Geologic Sediments microbiology, Seawater microbiology
- Published
- 2010
27. [Scanning for sulfate-degrading bacteria from a mat of hydrothermal field of Lost City by molecular cloning techniques ].
- Author
-
Gerasimchuk AL, Shatalov AA, Novikov AD, Butorova OP, Pimenov NV, Lein AIu, Ianenko AS, and Karnachuk OV
- Subjects
- Atlantic Ocean, Cloning, Molecular, Genes, Bacterial, Hot Temperature, Molecular Sequence Data, Oxidoreductases genetics, Peptococcaceae classification, Peptococcaceae genetics, Phylogeny, RNA, Bacterial genetics, RNA, Ribosomal, 16S genetics, Sulfur-Reducing Bacteria classification, Sulfur-Reducing Bacteria genetics, Geologic Sediments microbiology, Peptococcaceae isolation & purification, Sulfates metabolism, Sulfur-Reducing Bacteria isolation & purification
- Published
- 2010
28. [Sulfur metabolite bacteria from waste water of gold miner tale-depot in Kuzbass].
- Author
-
Karnachuk OV, Gerasimchuk AL, Banks D, Frengstad B, Stykon GA, Kaksonen AH, Puhakka J, Ianenko AS, and Pimenov NV
- Subjects
- Acidithiobacillus genetics, Colony Count, Microbial, Genes, Bacterial, Oxidation-Reduction, Peptococcaceae genetics, Peptococcaceae metabolism, Phylogeny, Siberia, Sulfur-Reducing Bacteria, Acidithiobacillus isolation & purification, Acidithiobacillus metabolism, Gold, Mining, Peptococcaceae isolation & purification, Sulfates metabolism, Sulfur metabolism, Water Microbiology
- Published
- 2009
29. [Biological fractionation of stable carbon isotopes at the aerobic/anaerobic water interface of meromictic water bodies].
- Author
-
Pimenov NV, Lunina ON, Prusakova TS, Rusanov II, and Ivanov MV
- Subjects
- Aerobiosis, Anaerobiosis, Bacteria metabolism, Fresh Water microbiology, Mass Spectrometry, Phytoplankton metabolism, Phytoplankton microbiology, Russia, Seasons, Carbon Isotopes analysis, Fresh Water chemistry, Photosynthesis
- Abstract
Mass-spectrometric investigation of carbon isotope composition (delta13C) was carried out for suspended organic matter and dissolved mineral compounds for the water column of some meromictic water bodies differing in salinity and trophic state. As a rule, a more pronounced carbon isotope fractionation (resulting from the metabolism of phytoplankton and anoxygenic phototrophic bacteria) was revealed in the zones of enhanced oxygenic and anoxygenic photosynthesis. Carbon isotope fractionation at the border between oxidized and reduced waters depends both on the activity of microbial communities and on the dominant species of phototrophic microorganisms. Analysis of the distribution profiles of the isotopic composition of suspended organic matter and dissolved mineral carbon revealed active mineralization of the organic matter newly formed via anoxygenic photosynthesis in the monimolimnion by microbial communities, resulting in the release of isotopically light carbon dioxide. Mineral carbon in the anaerobic zones of highly productive meromictic water bodies is therefore enriched with the light 12C isotope.
- Published
- 2008
30. [Microbiological and biogeochemical processes in a pockmark of the Gdansk depression, Baltic Sea].
- Author
-
Pimenov NV, Ul'ianova MO, Kanapatski TA, Sivkov VV, and Ivanov MV
- Subjects
- Anaerobiosis, Archaea isolation & purification, Bacteria isolation & purification, Carbon Dioxide analysis, Carbon Dioxide metabolism, Carbon Isotopes analysis, Colony Count, Microbial, Geologic Sediments analysis, Methane analysis, Oceans and Seas, Oxidation-Reduction, Poland, Sulfates analysis, Sulfates metabolism, Water Microbiology, Archaea metabolism, Bacteria metabolism, Geologic Sediments microbiology, Methane metabolism, Seawater chemistry, Seawater microbiology
- Abstract
Comprehensive microbiological and biogeochemical investigation of a pockmark within one of the sites of gas-saturated sediments in the Gdansk depression, Baltic Sea was carried out during the 87th voyage of the Professor Shtokman research vessel. Methane content in the near-bottom water and in the underlying sediments indicates stable methane flow from the sediment into the water. In the 10-m water layer above the pockmark, apart from methane anomalies, elevated numbers of microorganisms and enhanced rates of dark CO2 fixation (up to 1.15 micromol C/(1 day)) and methane oxidation (up to 2.14 nmol CH4/(1 day)) were revealed. Lightened isotopic composition of suspended organic matter also indicates high activity of the near-bottom microbial community. Compared to the background stations, methane content in pockmark sediments increased sharply from the surface to 40-60 ml/dm3 in the 20-30cm horizon. High rates of bacterial sulfate reduction (SR) were detected throughout the core (0-40 cm); the maximum of 74 micromol/(dm3 day) was located in subsurface horizons (15-20 cm). The highest rates of anaerobic methane oxidation (AMO), up to 80 micromol/(dm3 day), were detected in the same horizon. Good coincidence of the AMO and SR profiles with stoichiometry close to 1:1 is evidence in favor of a close relation between these processes performed by a consortium of methanotrophic archaea and sulfate-reducing bacteria. Methane isotopic composition in subsurface sediments of the pockmark (from -53.0 to -56.5% per hundred) does not rule out the presence of methane other than the biogenic methane from the deep horizons of the sedimentary cover.
- Published
- 2008
31. [Anoxygenic phototrophic bacteria of the high-altitude meromictic Lake Gek-Gel, Azerbaijan].
- Author
-
Lunina ON, Kevbrina MV, Akimov VN, and Pimenov NV
- Subjects
- Anaerobiosis, Azerbaijan, Chlorobium isolation & purification, Chlorobium metabolism, Chlorobium ultrastructure, Colony Count, Microbial, Hyphomicrobiaceae isolation & purification, Hyphomicrobiaceae metabolism, Hyphomicrobiaceae ultrastructure, Microscopy, Electron, Photosynthesis, Phylogeny, Chlorobium classification, Fresh Water microbiology, Hyphomicrobiaceae classification
- Abstract
The anoxygenic phototrophic bacterial community of the high-altitude meromictic Lake Gek-Gel (Azerbaijan) was investigated in September 2003. The highest concentration of bacteriochlorophyll e (48 microg/l) was detected at a depth of 30 m; the peak of bacteriochlorophyll a (4.5 microg/l) occurred at 29 m. Phylogenetic analysis revealed that brown-colored green sulfur bacteria Chlorobium phaeobacteroides predominated in the lake. Nonsulfur purple bacteria phylogenetically close to Blastochloris sulfoviridis were found in insignificant amounts; these organisms have not been previously reported in Lake Gek-Gel.
- Published
- 2008
32. [Application of 13C mineral carbon for assessment of the primary production of organic matter in aquatic environments].
- Author
-
Pimenov NV, Ziakun AM, Prusakova TS, Lunina ON, and Ivanov MV
- Subjects
- Ecosystem, Organic Chemicals metabolism, Russia, Substrate Cycling, Carbon Isotopes, Fresh Water analysis, Mass Spectrometry methods, Organic Chemicals analysis
- Abstract
The possibility of measuring the rates of light and dark CO2 assimilation using 13C carbonate was demonstrated on Lake Kichier (Marii El). The application of methods utilizing the stable 13C and the radioactive 14C isotopes resulted in comparable values of the rates of light and dark CO2 fixation. Due to its absolute environmental safety, the method with 13C mineral carbon can be recommended as an alternative to radioisotope methods for qualitative measurements of CO2 fixation rates in aquatic ecosystems.
- Published
- 2008
33. [Microbial processes of the carbon and sulfur cycles in the Chukchi Sea].
- Author
-
Savvichev AS, Rusanov II, Pimenov NV, Zakharova EE, Veslopolova EF, Lein AIu, Crane K, and Ivanov MV
- Subjects
- Arctic Regions, Bacteria isolation & purification, Colony Count, Microbial, Ecosystem, Methane analysis, Methane metabolism, Oxidation-Reduction, Seawater analysis, Siberia, Carbon metabolism, Geologic Sediments microbiology, Marine Biology, Seawater microbiology, Sulfur metabolism, Water Microbiology
- Abstract
The research performed in August 2004 within the framework of the Russian-American Long-term Census of the Arctic (RUSALCA) resulted in the first data concerning the rates of the key microbial processes in the water column and bottom sediments of the Bering strait and the Chukchi Sea. The total bacterial counts in the water column varied from 30 x 10(3) cells ml(-1) in the northern and eastern parts to 245 x 10(3) cells ml(-1) in the southern part. The methane content in the water column of the Chukchi sea varied from 8 nmol CH4 l(-1) in the eastern part of the sea to 31 nmol CH4 l(-1) in the northern part of the Herald Canyon. Active microbial processes occurred in the upper 0-3 cm of the bottom sediments; the methane formation rate varied from 0.25 to 16 nmol CH4 dm(-3) day(-1). The rates of methane oxidation varied from 1.61 to 14.7 nmol CH4 dm(-3) day(-1). The rates of sulfate reduction varied from 1.35 to 16.2 micromol SO4(2-) dm(-3) day(-1). The rate of methane formation in the sediments increased with depth, while sulfate reduction rates decreased (less than 1 micromol SO4(2-) dm(-3) day(-1)). These high concentrations of biogenic elements and high rates of microbial processes in the upper sediment layers suggest a specific type of trophic chain in the Chukchi Sea. The approximate calculated balance of methane emission from the water column into the atmosphere is from 5.4 to 57.3 micromol CH4 m(-2) day(-1).
- Published
- 2007
34. [Radioisotopic assays of rates of carbon monoxide conversion by anaerobic thermophilic prokaryotes].
- Author
-
Slepova TV, Rusanov II, Sokolova TG, Bonch-Osmolovskaia EA, and Pimenov NV
- Subjects
- Bacteria, Anaerobic growth & development, Carbon Dioxide analysis, Carbon Dioxide metabolism, Gram-Positive Rods growth & development, Hot Springs microbiology, Oxidation-Reduction, Scintillation Counting, Bacteria, Anaerobic metabolism, Bacteriological Techniques methods, Carbon Monoxide metabolism, Gram-Positive Rods metabolism
- Abstract
The rate of CO conversion by a pure culture of a thermophilic CO-oxidizing, H2-producing bacterium Carboxydocella sp. strain 1503 was determined by the radioisotopic method. The overall daily uptake of 14CO by the bacterium was estimated at 38-56 micromol CO per 1 ml of the culture. A radioisotopic method was developed to separate and quantitatively determine the products of anaerobic CO conversion by microbial communities in hot springs. The new method was first tested on the microbial community from a sample obtained from a hot spring in Kamchatka. The potential rate of CO conversion by the anaerobic microbial community was found to be 40.75 nmol CO/cm3 sediment per day. 85% of the utilized 14CO was oxidized to carbon dioxide; 14.5% was incorporated into dissolved organic matter, including 0.2% that went into volatile fatty acids; 0.5% was used for cell bio mass production; and only just over 0.001% was converted to methane.
- Published
- 2007
35. [Anoxygenic phototrophic bacterial community of Lake Shira (Khakassia)].
- Author
-
Lunina ON, Briantseva IA, Akimov VN, Rusanov II, Barinova ES, Lysenko AM, Rogozin DIu, and Pimenov NV
- Subjects
- Chlorobi classification, Chromatiaceae classification, Ecosystem, Phototrophic Processes, Phylogeny, Rhodospirillaceae classification, Chlorobi isolation & purification, Chromatiaceae isolation & purification, Fresh Water microbiology, Rhodospirillaceae isolation & purification
- Abstract
The anoxygenic phototrophic bacterial community of the brackish meromictic Lake Shira (Khakassia) was investigated in August 2001, July 2002, and February-March 2003. In all the periods of investigation, the prevailing microorganisms were purple sulfur bacteria similar to Lamprocystis purpurea in morphology and pigment composition. Their highest number (3 x 10(5) cells/ml) was recorded in July 2002 at the depth of 15 m. According to 16S rRNA gene analysis, the strain of purple sulfur bacteria isolated in 2001 and designated ShAm01 exhibited 98.6% similarity to the type strain of Thiocapsa roseopersicina and 94.4-97.1% similarity to the type strains of Tca. pendens, Tca. litoralis, and Tea. rosea. The minor microorganisms of the anoxygenic phototrophic bacterial community within the period of investigation were nonsulfur purple bacteria phylogenetically close to Rhodovulum strictum (98.3% similarity, strain ShRb01), Ahrensia kielensis (of 93.9% similarity, strain ShRb02), Rhodomicrobium vannieli (of 99.7% similarity, strain ShRmc01), and green sulfur bacteria, phylogenetically close to Chlorobium limicola (of 98.7% similarity, strain ShCl03).
- Published
- 2007
36. [Seasonal changes in the structure of the anoxygenic photosynthetic bacterial community in Lake Shunet, Khakassia].
- Author
-
Lunina ON, Briantseva IA, Akimov VN, Rusanov II, Rogozin DIu, Barinova ES, Lysenko AM, and Pimenov NV
- Subjects
- Anaerobiosis, Fresh Water analysis, Phylogeny, RNA, Bacterial genetics, RNA, Ribosomal, 16S genetics, Rhodobacteraceae genetics, Rhodobacteraceae ultrastructure, Siberia, Environmental Monitoring, Fresh Water microbiology, Rhodobacteraceae isolation & purification, Seasons, Water Microbiology
- Abstract
Seasonal studies of the anoxygenic phototrophic bacterial community of the water column of the saline eutrophic meromictic Lake Shunet (Khakassia) were performed in 2002 (June) and 2003 (February-March and August). From the redox zone down, the lake water was of dark green color. Green sulfur bacteria predominated in every season. The maximum number of green sulfur bacteria was 10(7) cells/ml in summer and 10(6) cells/ml in winter. A multi-syringe stratification sampler was applied for the study of the fine vertical distribution of phototrophs in August 2003; the sampling was performed every five centimeters. A five-centimeter-thick pink-colored water layer inhabited by purple sulfur bacteria was shown to be located above the layer of green bacteria. The species composition and ratio of purple bacterial species depended on the sampling depth and on the season. In summer, the number of purple sulfur bacteria in the layer of pink water was 1.6 x 10(8) cells/ml. Their number in winter was 3 x 10(5) cells/ml. In the upper oxygen-containing layer of the chemocline the cells of purple nonsulfur bacteria were detected in summer. The maximum number of nonsulfur purple bacteria, 5 x 10(2) cells/ml, was recorded in August 2003. According to the results of the phylogenetic analysis of pure cultures of the isolated phototrophic bacteria, which were based on 16S rDNA sequencing, green sulfur bacteria were close to Prosthecochloris vibrioformis, purple sulfur bacteria, to Thiocapsa and Halochromatium species, and purple nonsulfur bacteria, to Rhodovulum euryhalinum and Pinkicyclus mahoneyensis.
- Published
- 2007
37. [Phylogenetic characterization of endosymbionts of the hydrothermal vent mussel Bathymodiolus azoricus by analysis of the 16S rRNA, pmoL, and cbbA genes].
- Author
-
Spiridonova EM, Kuznetsov BB, Pimenov NV, and Turova TP
- Subjects
- Animals, Bacterial Proteins genetics, Gammaproteobacteria classification, Gammaproteobacteria genetics, Gills microbiology, Marine Biology, Methylobacteriaceae classification, Methylobacteriaceae genetics, Oxygenases genetics, Phylogeny, RNA, Bacterial genetics, RNA, Ribosomal, 16S genetics, Ribulose-Bisphosphate Carboxylase genetics, Species Specificity, Bivalvia microbiology, Gammaproteobacteria isolation & purification, Methylobacteriaceae isolation & purification, Symbiosis
- Abstract
In order to assess the phylogenetic diversity of the endosymbiotic microbial community of the gills of marine shellfish Bathymodiolus azoricus, total DNA was extracted from the gills. The PCR fragments corresponding to the genes encoding 16S rRNA, ribulose-bisphosphate carboxylase (cbbL), and particulate methane monooxygenase (pmoA) were amplified, cloned, and sequenced. For the 16S rDNA genes, only one phylotype was revealed; it belonged to the cluster of Mytilidae thiotrophic symbionts within the Gammaproteobacteria. For the RuBisCO genes, two phylotypes were found, both belonging to Gammaproteobacteria. One of them was closely related to the previously known mytilid symbiont, the other, to a pogonophore symbiont, presumably a methanotrophic bacterium. One phylotype of particulate methane oxygenase genes was also revealed; this finding indicated the presence of a methanotrophic symbiont. Phylogenetic analysis of the pmoA placed this endosymbiont within the Gammaproteobacteria, in a cluster including the methanotrophic bacterial genus Methylobacter and other methanotrophic Bathymodiolus gill symbionts. These results provide evidence for the existence of two types of endosymbionts (thioautotrophic and methanotrophic) in the gills of B. azoricus and demonstrate that, apart from the phylogenetic analysis of 16S rRNA genes, parallel analysis of functional genes is essential.
- Published
- 2006
38. [Sulfate reduction and methanogenesis in the Shira and Shunet meromictic lakes (Khakass Republic, Russia)].
- Author
-
Kallistova AIu, Kevbrina MV, Pimenov NV, Rusanov II, Rogozin DIu, Wehrli B, and Nozhevnikova AN
- Subjects
- Archaea metabolism, Bacteria metabolism, Fresh Water chemistry, Geologic Sediments microbiology, Oligonucleotide Probes, Primed In Situ Labeling, RNA, Bacterial, RNA, Ribosomal, Siberia, Archaea isolation & purification, Bacteria isolation & purification, Fresh Water microbiology, Methane biosynthesis, Sulfates metabolism, Water Microbiology
- Abstract
The biogeochemical and molecular biological study of the chemocline and sediments of saline meromictic lakes Shira and Shunet (Khakass Republic, Russia) was performed. A marked increase in the rates of sulfate reduction and methanogenesis was revealed at the medium depths of the chemocline. The rates of these processes in the bottom sediments decreased with depth. The numbers of Bacteria, Archaea, and of sulfate-reducing bacteria (SRB) were determined by fluorescence in situ hybridization with rRNA specific oligonucleotide probes labeled with horseradish peroxidase and subsequent tyramide signal amplification. In the chemocline, both the total microbial numbers and those of Bacteria were shown to increase with depth. The archaea and SRB were present in almost equal numbers. In the lake sediments, a drastic decrease in microbial numbers with depth was revealed. SRB were found to prevail in the upper sediment layer and archaea in the lower one. This finding correlates with the measured rates of sulfate reduction and methanogenesis.
- Published
- 2006
39. [Organotrophic activity in Kamchatka Hot Springs with low pH].
- Author
-
Prokof'eva MI, Rusanov II, Pimenov NV, and Bonch-Osmolovskaia EA
- Subjects
- Bacteria, Aerobic isolation & purification, Bacteria, Anaerobic isolation & purification, Asia, Eastern, Hydrogen-Ion Concentration, Russia, Bacteria, Aerobic metabolism, Bacteria, Anaerobic metabolism, Hot Springs chemistry, Hot Springs microbiology
- Published
- 2006
40. [Distribution, diversity, and activity of sulfate-reducing bacteria in the water column in Gek-Gel Lake, Azerbaijan].
- Author
-
Karnachuk OV, Pimenov NV, Iusupov SK, Frank IuA, Puhakka JA, and Ivanov MV
- Subjects
- Bacterial Typing Techniques methods, In Situ Hybridization, Fluorescence, Sulfur-Reducing Bacteria classification, Sulfur-Reducing Bacteria genetics, Sulfur-Reducing Bacteria growth & development, Water Microbiology
- Abstract
The distribution and activity of sulfate-reducing bacteria (SRB) in the water column of the alpine meromictic Gek-Gel lake were studied. Apart from traditional microbiological methods based on cultivation and on measuring the process rates with radioactive labels, in situ fluorescent hybridization (FISH) was used, which enables identification and quantification without cultivating organisms. The peak rate of sulfate reduction, 0.486 microg S/(l day), was found in the chemocline at 33 m. The peak SRB number of 2.5 x 106 cells/ml, as determined by the end-point dilutions method on selective media, was found at the same depth. The phylogenetic position of the SRB, as determined by FISH, revealed the predominance of the Desulfovibrio spp., Desulfobulbus spp., and Desulfoarculus spp./Desulfomonile spp. groups. The numbers of spore-forming Desulfotomaculum spp. increased with depth. The low measured rates of sulfate reduction accompanied with high SRB numbers and the predominance of the groups capable of reducing a wide range of substrates permit us to propose utilization of electron acceptors other than sulfate as the main activity of the SRB in the water column.
- Published
- 2006
41. [Seasonal changes in the structure of the anoxygenic phototrophic bacterial community in Lake Mogilnoe, a relict lake on Kil'din Island in the Barents Sea].
- Author
-
Lunina ON, Gorlenko VM, Solov'eva OA, Akimov VN, Rusanov II, and Pimenov NV
- Subjects
- Chlorobium isolation & purification, Chlorophyll analysis, Chlorophyll metabolism, Colony Count, Microbial, Ecosystem, Gram-Negative Anaerobic Bacteria genetics, Gram-Negative Anaerobic Bacteria ultrastructure, Photosynthesis, Phylogeny, Russia, Seasons, Species Specificity, Sulfur metabolism, Fresh Water microbiology, Gram-Negative Anaerobic Bacteria isolation & purification, Gram-Negative Anaerobic Bacteria metabolism, Water Microbiology
- Abstract
An anaerobic phototrophic bacterial community in Lake Mogilnoe, a relict lake on Kil'din Island in the Barents Sea, was studied in June 1999 and September 2001. Irrespective of the season, the upper layer of the anaerobic zone of this lake had a specific species composition of sulfur phototrophic bacteria, which were dominated by the brown-colored green sulfur bacterium Chlorobium phaeovibrioides. The maximum number of phototrophic sulfur bacteria was observed in June 1999 at a depth of 9 m, which corresponded to a concentration of bacteriochlorophyll (Bchl) e equal to 4.6 mg/l. In September 2001, the maximum concentration of this pigment (3.4 mg/l) was found at a depth of 10 m. In both seasons, the concentration of Bchl a did not exceed 3 microg/l. Purple sulfur bacteria were low in number, which can be explained by their poor adaptation to the hydrochemical and optical conditions of the Lake Mogilnoe water. In June 1999, the water contained a considerable number of Pelodictyon phaeum microcolonies and Prosthecochloris phaeoasteroides cell chains, which was not the case in September 2001. A 16S rDNA-based phylogenetic analysis of pure cultures of phototrophic bacteria isolated from the lake water confirmed that the bacterial community is dominated by Chl. phaeovibrioides and showed the presence of three minor species, Thiocvstis gelatinosa, Thiocapsa sp., and Thiorhodococcus sp., the last of which is specific to Lake Mogilnoe.
- Published
- 2005
42. [Microbiological and isotopic-geochemical investigations of meromictic lakes in Khakasia in winter].
- Author
-
Savvichev AS, Rusanov II, Rogozin DIu, Zakharova EE, Lunina ON, Briantseva IA, Iusupov SK, Pimenov NV, Degermendzhi AG, and Ivanov MV
- Subjects
- Bacteria metabolism, Carbon Isotopes analysis, Carbon Isotopes metabolism, Methane metabolism, Oxidation-Reduction, Seasons, Siberia, Species Specificity, Sulfates metabolism, Sulfur Isotopes analysis, Sulfur Isotopes metabolism, Bacteria isolation & purification, Bacterial Physiological Phenomena, Fresh Water, Photosynthesis, Water Microbiology
- Abstract
Microbiological and isotopic-geochemical investigations of the brackish meromictic lakes Shira and Shunet were performed in the steppe region of Khakasia in winter. Measurements made with a submersed sensor demonstrated that one-meter ice transmits light in a quantity sufficient for oxygenic and anoxygenic photosynthesis. As in the summer season, in the community of phototrophic bacteria found in Lake Shira, the purple sulfur bacteria Amoebobacter purpureus dominated, whereas, in Lake Shunet, the green sulfur bacteria Pelodictyon luteolum were predominant. Photosynthetic production, measured using the radioisotopic method, was several times lower than that in summer. The rates of sulfate reduction and production and oxidation of methane in the water column and bottom sediments were also lower than those recorded in summer. The process of anaerobic methane oxidation in the sediments was an exception, being more intense in winter than in summer. The data from radioisotopic measurements of the rates of microbial processes correlate well with the results of determination of the isotopic composition of organic and mineral carbon (delta13C) and hydrogen sulfide and sulfate (delta34S) and suggest considerable seasonal variations in the activity of the microbial community in the water bodies investigated.
- Published
- 2005
43. [Anaerobic methane oxidation and sulfate reduction in bacterial mats of coral-like carbonate structures in the Black Sea].
- Author
-
Pimenov NV and Ivanova AE
- Subjects
- Anaerobiosis, Animals, Anthozoa microbiology, Ecosystem, Oceans and Seas, Oxidation-Reduction, Carbonates metabolism, Methane metabolism, Seawater microbiology, Sulfates metabolism, Sulfur-Reducing Bacteria metabolism
- Abstract
A detailed study of the processes of anaerobic methane oxidation and sulfate reduction in the bacterial mats occurring on coral-like carbonate structures in the region of methane seeps in the Black Sea, as well as of the phenotypic diversity of sulfate-reducing bacteria developing in this zone, has been performed. The use of the radioisotopic method shows the microbial mat structure to be heterogeneous. The peak activity of the two processes was revealed when a mixture of the upper (dark) and underlying (intensely pink) layers was introduced into an incubation flask, which confirms the suggestion that methanotrophic archaea and sulfate-reducing bacteria closely interact in the process of anaerobic methane oxidation. Direct correlation between the rate of anaerobic methane oxidation and the methane and electron acceptor concentrations in the medium has been experimentally demonstrated. Several enrichment and two pure cultures of sulfate-reducing bacteria have been obtained from the near-bottom water and bacterial mats. Both strains were found to completely oxidize the substrates to CO2 and H2S. The bacteria grow at temperatures ranging from -1 to 18 (24) degrees C, with an optimum in the 10-18 degrees C range, and require the presence of 1.5-2.5% NaCl and 0.07-0.2% MgCl2 x 6H2O. Regarding the aggregate of their phenotypic characteristics (cell morphology, spectrum of growth substrates, the capacity for complete oxidation), the microorganisms isolated have no analogues among the psychrophilic sulfate-reducing bacteria already described. The results obtained demonstrate the wide distribution of psychrophilic sulfate-reducing bacteria in the near-bottom water and bacterial mats covering the coral-like carbonate structures occurring in the region of methane seeps in the Black Sea, as well as the considerable catabolic potential of this physiological group of psychrophilic anaerobes in deep-sea habitats.
- Published
- 2005
44. [Ecophysiological properties of photosynthesizing bacteria from the Black Sea chemocline zone].
- Author
-
Gorlenko VM, Mikheev PV, Rusanov II, Pimenov NV, and Ivanov MV
- Subjects
- Carbon Dioxide metabolism, Chlorobium isolation & purification, Chlorobium ultrastructure, Culture Media, Ecosystem, Ethanol, Fresh Water, Geologic Sediments microbiology, Russia, Seawater, Sodium Acetate, Sulfides metabolism, Chlorobium physiology, Marine Biology, Photosynthesis
- Abstract
In May 1998, during the fifty-first voyage on board the research vessel Professor Vodyanitskii, a comparative study was conducted of the species diversity of green and purple sulfur bacteria in the water column of the chemocline zone at deep-sea stations and on the bottom surface of the Black Sea shallow regions. At three deep-sea stations, the accumulation of photosynthesizing bacteria in the chemocline zone at a depth of 85-115 m was revealed on the basis of the distribution of potential values of carbon dioxide light fixation. The location of the site of potential carbon dioxide light fixation suggests that the photosynthesis may be determined by the activity of the brown Chlorobium sp., revealed earlier at these depths. Enrichment cultures of brown sulfur bacteria were obtained from samples taken at the deep-sea stations. By morphology, these bacteria, assigned to Chlorobium sp., appear as nonmotile straight or slightly curved rods 0.3-0.5 x 0.7-1.2 microm in size; sometimes, they form short chains. Ultrathin sections show photosynthesizing antenna-like structures, chlorosomes, typical of Chlorobiaceae. The cultures depended on the presence of NaCl (20 g/l) for growth, which corresponds to the mineralization of Black Sea water. The bacteria could grow photoautotrophically, utilizing sulfide, but the Black Sea strains grew much more slowly than the known species of brown sulfur bacteria isolated from saline or freshwater meromictic lakes. The best growth of the strains studied in this work occurred in media containing ethanol (0.5 g) or sodium acetate (1 g/l) and low amounts of sulfide (0.4 mM), which is consistent with the conditions of syntrophic growth with sulfidogens. The data obtained allow us to conclude that the cultures of brown sulfur bacteria are especially adapted to developing at large depths under conditions of electron donor deficiency owing to syntrophic development with sulfate reducers. The species composition of the photosynthetic bacteria developing in the bottom sediments of shallow stations differed substantially from that observed at deep-sea stations. Pure cultures of the green Chlorobium sp. BS 1C and BS 2C (chlorobactin as the carotenoid), purple sulfur bacteria Chromatium sp. BS 1Ch (containing spirilloxanthine series pigments), and Thiocapsa marina BS 2Tc (containing the carotenoid okenone) were obtained from samples of sediments at shallow-water stations. Brown sulfur bacteria were absent in the sediment samples obtained from the Black Sea shallow-water stations 1 and 2.
- Published
- 2005
45. [The processes of methane formation and oxidation in the soils of the Russian arctic tundra].
- Author
-
Berestovskaia IuIu, Rusanov II, Vasil'eva LV, and Pimenov NV
- Subjects
- Arctic Regions, Methane chemistry, Oxidation-Reduction, RNA, Bacterial analysis, RNA, Ribosomal, 16S analysis, Rhizobiaceae genetics, Rhizobiaceae isolation & purification, Russia, Seasons, Soil analysis, Temperature, Methane metabolism, Rhizobiaceae metabolism, Soil Microbiology
- Abstract
Methane emission from the following types of tundra soils was studied: coarse humic gleyey loamy cryo soil, peaty gley soil, and peaty gleyey midloamy cryo soil of the arctic tundra. All the soils studied were found to be potential sources of atmospheric methane. The highest values of methane emission were recorded in August at a soil temperature of 8-10 degrees C. Flooded parcels were the sources of atmospheric methane throughout the observation period. The rates of methane production and oxidation in tundra soils of various types at 5 and 15 degrees C were studied by the radioisotope method. Methane oxidation was found to occur in bog water, in the green part of peat moss, and in all the soil horizons studied. Methane formation was recorded in the horizons of peat, in clay with plant roots, and in peaty moss dust of the bogey parcels. At both temperatures, the methane oxidation rate exceeded the rate of methane formation in all the horizons of the mossy-lichen tundra and of the bumpy sinkhole complex. Methanogenesis prevailed only in a sedge-peat moss bog at 15 degrees C. Enrichment bacterial cultures oxidizing methane at 5 and 15 degrees C were obtained. Different types of methanotrophic bacteria were shown to be responsible for methane oxidation under these conditions. A representative of type I methylotrophs oxidized methane at 5 degrees C, and Methylocella tundrae, a psychroactive representative of an acidophilic methanotrophic genus Methylocella, at 15 degrees C.
- Published
- 2005
46. [Microbiological processes in the Lost City vent field, mid-Atlantic ridge].
- Author
-
Dulov LE, Lein AIu, Dubinina GA, and Pimenov NV
- Subjects
- Atlantic Ocean, Carbon Dioxide metabolism, Ecosystem, Methane metabolism, Oxidation-Reduction, Sulfates metabolism, Bacteria metabolism, Geologic Sediments microbiology, Seawater microbiology
- Abstract
Microbiological and biogeochemical measurements showed that the intensities of CO2 assimilation, methane oxidation, and sulfate reduction in the Lost City vent field (30 degrees N) reach 3.8 microg C/(1 day), 0.06 microg C/(1 day), and 117 microg S/(1 day), respectively. On the surface of the carbonate structures occurring in this field, two varieties of bacterial mats were found. The first variety, which is specific to the Lost City alkaline vent field, represents jelly bacterial mats dominated by slime-producing bacteria of several morphotypes. This mat variety also contains chemolithotrophic and heterotrophic microorganisms, either microaerobic or anaerobic. The intensities of CO2 assimilation, methane oxidation, and sulfate reduction in this variety reach 747 microg C/(dm3 day), 0.02 microg C/(dm3 day), and 28,000 microg S/(dm3 day), respectively. Bacterial mats of the second variety are formed by nonpigmented filamentous sulfur bacteria, which are close morphologically to Thiothrix. The intensities of CO2 assimilation, methane oxidation, and sulfate reduction in the second mat variety reach 8.2 microg C/(dm3 day), 5.8 microg C/(dm3 day), and 17,000 microg S/(dm3 day), respectively. These data suggest the existence of subsurface microflora in the Lost City vent field.
- Published
- 2005
47. [The biogeochemical cycle of methane in the coastal zone and littoral of the Kandalaksha Bay of the White Sea].
- Author
-
Savvichev AS, Rusanov II, Iusupov SK, Pimenov NV, Lein AIu, and Ivanov MV
- Subjects
- Bacteria isolation & purification, Carbon analysis, Carbon Dioxide metabolism, Colony Count, Microbial, Ecosystem, Fresh Water analysis, Fresh Water microbiology, Geologic Sediments analysis, Oxidation-Reduction, Phytoplankton isolation & purification, Russia, Seasons, Seawater analysis, Soil analysis, Temperature, Bacteria metabolism, Geologic Sediments microbiology, Marine Biology, Methane metabolism, Seawater microbiology, Water Microbiology
- Abstract
Microbiological and biogeochemical investigations of the processes of methane production (MP) and methane oxidation (MO) in the coastal waters and littoral of the Kandalaksha Bay of the White Sea were carried out. The studies were conducted in the coastal zones and in the water areas of the Kandalaksha Preserve, Moscow University White Sea Biological Station, and Zoological Institute (RAS) Biological Station in August, 1999, 2000, and 2001 and in March, 2001. The rate of CO2 assimilation in the shallow and littoral sediments was 35-27800 microg C/(dm3 day) in summer and 32.8-88.9 microg C/(dm3 day) in winter. The maximal rates of MP were observed in the littoral sediments in the zone of macrophyte decomposition, in local depressions, and in the estuary of a freshwater creak (up to 113 microl/(dm3 day)). The maximal level of MO was observed in the shallow estuarine sediments (up to 2450 microl/(dm3 day)). During the winter season, at the temperature of -0.5 to 0.5 degrees C, the MP rate in the littoral sediments was 0.02-0.3 microl/(dm3 day), while MO rate was 0.06-0.7 microl/(dm3 day). The isotopic data obtained indicate that the C(org) of the mats and of the upper sediment layers is enriched with the heavy 13C isotope by 1-4 per thousand as compared to the C(org) of the suspension, comprised on 33.5-34.3% of phytoplankton. A striking difference was found between the levels of methane emission by the typical littoral microlanscapes. In fine sediments, the average emission was 675 microl CH4/(m2 day), in the stormy discharge stretch sediments it was 1670 microl CH4/(m2 day), and under the stones and in silted pits, 1370 microl CH4/(m2 day). The calculation performed with consideration of the microlandscape areas with a high production allowed the CH4 production of 1 km2 of the littoral to be estimated as 192-300 1 CH4/(km2 day).
- Published
- 2004
48. [Microbial sulfate reduction in sediments of the coastal zone and littoral of the Kandalaksha bay of the White sea].
- Author
-
Savvichev AS, Rusanov II, Iusupov SK, Baĭramov IT, Pimenov NV, Lein AIu, and Ivanov MV
- Subjects
- Ecosystem, Hydrogen Sulfide analysis, Hydrogen Sulfide metabolism, Mass Spectrometry, Russia, Seasons, Sulfates analysis, Sulfates metabolism, Sulfur-Reducing Bacteria metabolism, Weather, Geologic Sediments microbiology, Seawater microbiology, Soil Microbiology, Sulfur-Reducing Bacteria isolation & purification, Water Microbiology
- Abstract
Microbiological and biogeochemical investigations of the coastal zone and the littoral of the Kandalaksha Bay of the White Sea were carried out. The material for investigations was obtained in the series of expeditions of the Institute of Microbiology, Russian Academy of Sciences, in August 1999, 2000, 2001, and in March 2003. The studies were conducted on the littoral and in the water area of the Kandalaksha Preserve, the Moscow University Belomorsk Biological Station, and the Zoological Institute Biological Station, Russian Academy of Sciences, Sediment sampling on the littoral was carried out in the typical microlandscapes differing in the sediment properties and macrobenthos distribution. The maximal sulfate reduction rate (SRR) was shown for the shallow part of the Chemorechenskaya Bay (up to 2550 micrograms S/(dm3 day)) and in the Bab'ye More Bay (up to 3191 micrograms S/(dm3 day)). During the winter season, at a temperature of -0.5-0.5 degrees C, the SRR in the sediments of the Kartesh Bay was 7.9-13 micrograms S/(dm3 day). In the widest limits, the SRR values varied in the sediment cores sampled on the littoral. The minimal values (11 mu]g S/(dm3 day)) were obtained in the core samples on the silt-sandy littoral. The littoral finely dispersed sediments rich in organic matter were characterized by high SRR values (524-1413 micrograms S/(dm3 day)). The maximal SRR values were shown for the sediments present within the stretch of decomposing macrophytes, in local pits at the lower littoral waterline, and in the mouth of a freshwater stream (51-159 mg S/(dm3 day)). A sharp difference in the level of H2S production in the type microlandscapes was shown. The average hydrogen sulfide production in finely dispersed sediments constituted 125 mg S/(m2 day); in stormy discharge deposits, 1950 mg S/(m2 day); in depressions under stones and in silted pits, 4300 mg S/(m2 day). A calculation made with regard to the area of microlandscapes with increased productivity shows that the daily H2S production per 1 km2 of the littoral (August) is 60.8 to 202 kg S/(km2 day), while the organic carbon consumption for sulfate reduction per 1 km2 of the littoral is 46 to 152 kg C(org)/(km2 day).
- Published
- 2003
49. [Microbial metabolism of the carbon and sulfur cycles in Shira Lake (Khakasia)].
- Author
-
Pimenov NV, Rusanov II, Karnachuk OV, Rogozin DIu, Briantseva IA, Lunina ON, Iusupov SK, Parnachev VP, and Ivanov MV
- Subjects
- Methane metabolism, Oxidation-Reduction, Photosynthesis, Russia, Sulfates metabolism, Carbon metabolism, Chromatiaceae metabolism, Fresh Water microbiology, Sulfur metabolism
- Abstract
Microbiological and biogeochemical studies of the meromictic saline Lake Shira (Khakasia) were conducted. In the upper part of the hydrogen-sulfide zone, at a depth of 13.5-14 m, there was a pale pink layer of water due to the development of purple bacteria (6 x 10(5) cells/ml), which were assigned by their morphological and spectral characteristics to Lamprocystis purpureus (formerly Amoebobacter purpurea). In August, the production of organic matter (OM) in Lake Shira was estimated to be 943 mg C/(m2 day). The contribution of anoxygenic photosynthesis was insignificant (about 7% of the total OM production). The share of bacterial chemosynthesis was still less (no more than 2%). In the anaerobic zone, the community of sulfate-reducing bacteria played a decisive role in the terminal decomposition of OM. The maximal rates of sulfate reduction were observed in the near-bottom water (114 micrograms S/(1 day)) and in the surface layer of bottom sediments (901 micrograms S/(dm3 day)). The daily expenditure of Corg for sulfate reduction was 73% of Corg formed daily in the processes of oxygenic and anoxygenic photosynthesis and bacterial chemosynthesis. The profile of methane distribution in the water column and bottom sediments was typical of meromictic reservoirs. The methane content in the water column increased beginning with the thermocline (7-8 m), and reached maximum values in the near-bottom water (17 microliters/l). In bottom sediments, the greatest methane concentrations (57 microliters/l) were observed in the surface layer (0-3 cm). The integral rate of methane formation in the water column and bottom sediments was almost an order of magnitude higher than the rate of its oxidation by aerobic and anaerobic methanotrophic microorganisms.
- Published
- 2003
50. [Utilization of methane and carbon dioxide by symbiotrophic bacteria in gills of Mytilidae (Bathymodiolus) from the Rainbow and Logachev hydrothermal fields on the Mid-Atlantic Ridge].
- Author
-
Pimenov NV, Kaliuzhnaia MG, Khmelenina VN, Mitiushina LL, and Trotsenko IuA
- Subjects
- Alcohol Oxidoreductases analysis, Aldehyde-Lyases metabolism, Animals, Atlantic Ocean, Carbon Dioxide metabolism, Gills microbiology, Methane metabolism, Methylobacterium genetics, Methylobacterium isolation & purification, Methylococcaceae genetics, Methylococcaceae isolation & purification, Microscopy, Electron, Oxygenases analysis, Phosphotransferases (Alcohol Group Acceptor) metabolism, Polymerase Chain Reaction, Ribulose-Bisphosphate Carboxylase metabolism, Symbiosis, Methylobacterium metabolism, Methylococcaceae metabolism, Mollusca microbiology
- Abstract
Bivalve mollusks Bathymodiolus asoricus and Bathymodiolus puteoserpentis collected from the Rainbow and Logachev hydrothermal fields during dives of Mir 1 and Mir 2 deep-sea manned submersibles were studied. Rates of methane oxidation and carbon dioxide assimilation in mussel gill tissue were determined by radiolabel analysis. During oxidation of 14Ch4, radiocarbon was detected in significant quantities not only in carbon dioxide but also in dissolved organic matter, most notably 14C-formate and 14C-acetate, occurring in a 2:1 ratio. Activities of hexulose-phosphate synthase, phosphoribulokinase, and ribulose 1,5-bisphosphate carboxylase were shown in the soluble fraction of gill tissue cells. At the same time, no activity of hydroxypyruvate reductase--the key enzyme of the serine pathway of C1-assimilation--was detected. The results of PCR amplification using genetic probes for membrane-bound methane monooxygenase (pmoA) and methanol dehydrogenase (mxaF) attest to the presence of the genes of these enzymes in the total DNA extracted from gill samples. However, no appropriate PCR responses were obtained with the mmoX primer system, which is a marker for soluble methane monooxygenase. All samples studied showed amplification with primers for the genera Methylobacter and Methylosphaera. At the same time, no genes specific to the genera Methylomonas, Methylococcus, Methylomicrobium, or Methylosinus and Methylocystis were detected. Electron microscopic examinations revealed the presence of two groups of endosymbiotic bacteria in the mussel gill tissue. The first group was represented by large cells possessing a complex system of cytoplasmic membranes, typical of methanotrophs of morphotype I. The other type of endosymbionts, having much smaller cells and lacking intracellular membrane structures, is likely to be constituted by sulfur bacteria.
- Published
- 2002
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