scholarly journals Effect of Substrate Concentration on Carbon Isotope Fractionation during Acetoclastic Methanogenesis by Methanosarcina barkeri and M. acetivorans and in Rice Field Soil

2009 ◽  
Vol 75 (9) ◽  
pp. 2605-2612 ◽  
Author(s):  
Dennis Goevert ◽  
Ralf Conrad
Keyword(s):  
Substrate Concentration ◽  
Isotope Fractionation ◽  
Rice Field ◽  
Methanosarcina Barkeri ◽  
16S Rrna Genes ◽  
Rrna Genes ◽  
Field Soil ◽  
Rice Field Soil ◽  
Pure Cultures ◽  
Acetoclastic Methanogenesis

ABSTRACT Methanosarcina is the only acetate-consuming genus of methanogenic archaea other than Methanosaeta and thus is important in methanogenic environments for the formation of the greenhouse gases methane and carbon dioxide. However, little is known about isotopic discrimination during acetoclastic CH4 production. Therefore, we studied two species of the Methanosarcinaceae family, Methanosarcina barkeri and Methanosarcina acetivorans, and a methanogenic rice field soil amended with acetate. The values of the isotope enrichment factor (ε) associated with consumption of total acetate (εac), consumption of acetate-methyl (εac-methyl) and production of CH4 (εCH4) were an εac of −30.5‰, an εac-methyl of −25.6‰, and an εCH4 of −27.4‰ for M. barkeri and an εac of −35.3‰, an εac-methyl of −24.8‰, and an εCH4 of −23.8‰ for M. acetivorans. Terminal restriction fragment length polymorphism of archaeal 16S rRNA genes indicated that acetoclastic methanogenic populations in rice field soil were dominated by Methanosarcina spp. Isotope fractionation determined during acetoclastic methanogenesis in rice field soil resulted in an εac of −18.7‰, an εac-methyl of −16.9‰, and an εCH4 of −20.8‰. However, in rice field soil as well as in the pure cultures, values of εac and εac-methyl decreased as acetate concentrations decreased, eventually approaching zero. Thus, isotope fractionation of acetate carbon was apparently affected by substrate concentration. The ε values determined in pure cultures were consistent with those in rice field soil if the concentration of acetate was taken into account.

scholarly journals Effect of Temperature on Carbon and Electron Flow and on the Archaeal Community in Methanogenic Rice Field Soil

2000 ◽  
Vol 66 (11) ◽  
pp. 4790-4797 ◽  
Author(s):  
Axel Fey ◽  
Ralf Conrad
Keyword(s):  
Steady State ◽  
Rice Field ◽  
Electron Flow ◽  
Rflp Analysis ◽  
Archaeal Community ◽  
16S Rrna Genes ◽  
Rrna Genes ◽  
Field Soil ◽  
Rice Field Soil ◽  
Different Temperatures

ABSTRACT Temperature is an important factor controlling CH4production in anoxic rice soils. Soil slurries, prepared from Italian rice field soil, were incubated anaerobically in the dark at six temperatures of between 10 to 37°C or in a temperature gradient block covering the same temperature range at intervals of 1°C. Methane production reached quasi-steady state after 60 to 90 days. Steady-state CH4 production rates increased with temperature, with an apparent activation energy of 61 kJ mol−1. Steady-state partial pressures of the methanogenic precursor H2 also increased with increasing temperature from <0.5 to 3.5 Pa, so that the Gibbs free energy change of H2 plus CO2-dependent methanogenesis was kept at −20 to −25 kJ mol of CH4 −1 over the whole temperature range. Steady-state concentrations of the methanogenic precursor acetate, on the other hand, increased with decreasing temperature from <5 to 50 μM. Simultaneously, the relative contribution of H2 as methanogenic precursor decreased, as determined by the conversion of radioactive bicarbonate to 14CH4, so that the carbon and electron flow to CH4 was increasingly dominated by acetate, indicating that psychrotolerant homoacetogenesis was important. The relative composition of the archaeal community was determined by terminal restriction fragment length polymorphism (T-RFLP) analysis of the 16S rRNA genes (16S rDNA). T-RFLP analysis differentiated the archaeal Methanobacteriaceae,Methanomicrobiaceae, Methanosaetaceae,Methanosarcinaceae, and Rice clusters I, III, IV, V, and VI, which were all present in the rice field soil incubated at different temperatures. The 16S rRNA genes of Rice cluster I andMethanosaetaceae were the most frequent methanogenic groups. The relative abundance of Rice cluster I decreased with temperature. The substrates used by this microbial cluster, and thus its function in the microbial community, are unknown. The relative abundance of acetoclastic methanogens, on the other hand, was consistent with their physiology and the acetate concentrations observed at the different temperatures, i.e., the high-acetate-requiring Methanosarcinaceae decreased and the more modest Methanosaetaceae increased with increasing temperature. Our results demonstrate that temperature not only affected the activity but also changed the structure and the function (carbon and electron flow) of a complex methanogenic system.

scholarly journals Dynamics of the Methanogenic Archaeal Community during Plant Residue Decomposition in an Anoxic Rice Field Soil

2008 ◽  
Vol 74 (9) ◽  
pp. 2894-2901 ◽  
Author(s):  
Jingjing Peng ◽  
Zhe Lü ◽  
Junpeng Rui ◽  
Yahai Lu
Keyword(s):  
Rice Field ◽  
Dynamic Structure ◽  
Archaeal Community ◽  
Plant Residue ◽  
16S Rrna Genes ◽  
Rrna Genes ◽  
Plant Residues ◽  
Field Soil ◽  
Rice Field Soil ◽  
Residue Decomposition

ABSTRACT Incorporation of plant residues strongly enhances the methane production and emission from flooded rice fields. Temperature and residue type are important factors that regulate residue decomposition and CH4 production. However, the response of the methanogenic archaeal community to these factors in rice field soil is not well understood. In the present experiment, the structure of the archaeal community was determined during the decomposition of rice root and straw residues in anoxic rice field soil incubated at three temperatures (15°C, 30°C, and 45°C). More CH4 was produced in the straw treatment than root treatment. Increasing the temperature from 15°C to 45°C enhanced CH4 production. Terminal restriction fragment length polymorphism analyses in combination with cloning and sequencing of 16S rRNA genes showed that Methanosarcinaceae developed early in the incubations, whereas Methanosaetaceae became more abundant in the later stages. Methanosarcinaceae and Methanosaetaceae seemed to be better adapted at 15°C and 30°C, respectively, while the thermophilic Methanobacteriales and rice cluster I methanogens were significantly enhanced at 45°C. Straw residues promoted the growth of Methanosarcinaceae, whereas the root residues favored Methanosaetaceae. In conclusion, our study revealed a highly dynamic structure of the methanogenic archaeal community during plant residue decomposition. The in situ concentration of acetate (and possibly of H2) seems to be the key factor that regulates the shift of methanogenic community.

scholarly journals Response of the protistan community of a rice field soil to different oxygen tensions

2017 ◽  
Vol 93 (5) ◽  
Author(s):  
Yuriko Takenouchi ◽  
Kazufumi Iwasaki ◽  
Jun Murase
Keyword(s):  
Rice Field ◽  
Field Soil ◽  
Rice Field Soil ◽  
Oxygen Tensions

scholarly journals Succession of methanogenic archaea in rice straw incorporated into a Japanese rice field: estimation by PCR-DGGE and sequence analyses

Archaea ◽  
2005 ◽  
Vol 1 (6) ◽  
pp. 391-397 ◽  
Author(s):  
Atsuo Sugano ◽  
Hidetaka Tsuchimoto ◽  
Tun Cho Cho ◽  
Makoto Kimura ◽  
Susumu Asakawa
Keyword(s):  
Rice Straw ◽  
Rice Field ◽  
Previous History ◽  
Methanogenic Archaea ◽  
Leaf Sheath ◽  
16S Rrna Genes ◽  
Rrna Genes ◽  
Crop Season ◽  
Rdna Sequencing ◽  
Archaeal Communities

The succession and phylogenetic profiles of methanogenic archaeal communities associated with rice straw decomposition in rice-field soil were studied by polymerase chain reaction-denaturing gradient gel electrophoresis (PCR-DGGE) analysis followed by 16S rDNA sequencing. Nylon bags containing either leaf sheaths or blades were buried in the plowed layer of a Japanese rice field under drained conditions during the off-crop season and under flooded conditions after transplanting. In addition, rice straw samples that had been buried in the rice field under drained conditions during the off-crop season were temporarily removed during spring plowing and then re-buried in the same rice field under flooded conditions at transplanting. Populations of methanogenic archaea were examined by amplification of the 16S rRNA genes in the DNA extracted from the rice straw samples. No PCR product was produced for samples of leaf sheath or blade prior to burial or after burial under drained conditions, indicating that the methanogen population was very small during decomposition of rice straw under oxic conditions. Many common bands were observed in rice straw samples of leaf sheath and blade during decomposition of rice straw under flooded conditions. Cluster analysis based on DGGE patterns divided methanogenic archaeal communities into two groups before and after the mid-season drainage. Sequence analysis of DGGE bands that were commonly present were closely related toMethanomicrobialesand Rice cluster I.Methanomicrobiales, Rice cluster I andMethanosarcinaleswere major members before the mid-season drainage, whereas the DGGE bands that characterized methanogenic archaeal communities after the mid-season drainage were closely related toMethanomicrobiales. These results indicate that mid-season drainage affected the methanogenic archaeal communities irrespective of their location on rice straw (sheath and blade) and the previous history of decomposition during the off-crop season.

scholarly journals Respiration of 13C-Labeled Substrates Added to Soil in the Field and Subsequent 16S rRNA Gene Analysis of 13C-Labeled Soil DNA

2003 ◽  
Vol 69 (3) ◽  
pp. 1614-1622 ◽  
Author(s):  
P. Padmanabhan ◽  
S. Padmanabhan ◽  
C. DeRito ◽  
A. Gray ◽  
D. Gannon ◽  
...  
Keyword(s):  
Organic Matter ◽  
Soil Organic Matter ◽  
16S Rrna ◽  
16S Rrna Genes ◽  
Rrna Genes ◽  
Gas Chromatography Mass Spectrometry ◽  
Rrna Gene ◽  
Labeled Compounds ◽  
Field Soil ◽  
Soil Dna

ABSTRACT Our goal was to develop a field soil biodegradation assay using 13C-labeled compounds and identify the active microorganisms by analyzing 16S rRNA genes in soil-derived 13C-labeled DNA. Our biodegradation approach sought to minimize microbiological artifacts caused by physical and/or nutritional disturbance of soil associated with sampling and laboratory incubation. The new field-based assay involved the release of 13C-labeled compounds (glucose, phenol, caffeine, and naphthalene) to soil plots, installation of open-bottom glass chambers that covered the soil, and analysis of samples of headspace gases for 13CO2 respiration by gas chromatography/mass spectrometry (GC/MS). We verified that the GC/MS procedure was capable of assessing respiration of the four substrates added (50 ppm) to 5 g of soil in sealed laboratory incubations. Next, we determined background levels of 13CO2 emitted from naturally occurring soil organic matter to chambers inserted into our field soil test plots. We found that the conservative tracer, SF6, that was injected into the headspace rapidly diffused out of the soil chamber and thus would be of little value for computing the efficiency of retaining respired 13CO2. Field respiration assays using all four compounds were completed. Background respiration from soil organic matter interfered with the documentation of in situ respiration of the slowly metabolized (caffeine) and sparingly soluble (naphthalene) compounds. Nonetheless, transient peaks of 13CO2 released in excess of background were found in glucose- and phenol-treated soil within 8 h. Cesium-chloride separation of 13C-labeled soil DNA was followed by PCR amplification and sequencing of 16S rRNA genes from microbial populations involved with 13C-substrate metabolism. A total of 29 full sequences revealed that active populations included relatives of Arthrobacter, Pseudomonas, Acinetobacter, Massilia, Flavobacterium, and Pedobacter spp. for glucose; Pseudomonas, Pantoea, Acinetobacter, Enterobacter, Stenotrophomonas, and Alcaligenes spp. for phenol; Pseudomonas, Acinetobacter, and Variovorax spp. for naphthalene; and Acinetobacter, Enterobacter, Stenotrophomonas, and Pantoea spp. for caffeine.

Evidence for Iron- and Sulfur-Oxidizing Bacteria and Archaea in a Currently Active Lignite Mining Area of Lusatia (Eastern Germany)

2009 ◽  
Vol 71-73 ◽  
pp. 97-100 ◽  
Author(s):  
H.M. Siebert ◽  
Thore Rohwerder ◽  
Wolfgang Sand ◽  
M. Strzodka ◽  
K.P. Stahmann
Keyword(s):  
16S Rrna ◽  
Mining Area ◽  
16S Rrna Genes ◽  
Open Pit ◽  
Rrna Genes ◽  
Published Data ◽  
Lignite Mining ◽  
Two Samples ◽  
Pure Cultures ◽  
Sulfur Oxidizing

The largest lignite mining area in Europe is located 150 km southeast of Berlin. Acidic lakes exist in this area, known to be caused by marcasite oxidation. Thirty-two samples from the open-pit brown coal-mine Jaenschwalde were analyzed for microorganisms. Cell numbers determined after separation from sand particles revealed concentrations of 102 to 107 microorganisms per g sample. In samples exposed to the air within an hour, up to 4x107 cells were counted. Measurement of metabolic activity by microcalorimetry showed for such samples up to 50 µW per g sand, whereas in heap samples (with low moisture) low or even no activity was measurable. DNA extraction was successful for 28 samples. In 26 samples microbial 16S rRNA genes were amplified by PCR. Acidithiobacillus ferrooxidans and At. thiooxidans specific amplificates were detected by nested PCR in 23 and 10 cases, respectively. A specific signal indicating Leptospirillum ferrooxidans was obtained with nine samples. Random samples were sequenced and showed 96 to 99 % identity with published data of all three species. Surprisingly, in four samples archaeal 16S rRNA genes were amplified by PCR. Sequencing of two samples showed 99 % identity with unidentified or uncultured archaea found in NCBI-databases. Molecular biology results for At. ferrooxidans as well as for At. thiooxidans were supported by successful isolations of pure cultures in 23 cases. Cultivation of the archaea failed so far. These data indicate that iron- and sulfur-oxidizing microorganisms occur at these sites in large numbers. If in addition the evidence for archaea can become verified, a screening for hot spots as the sites of their occurrence would become interesting.

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