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1.
Arjan Pol Richard A. Gage John M. Neis Joost W.M. Reijnen Chris Van der Drift Godfried D. Vogels 《Biochimica et Biophysica Acta (BBA)/General Subjects》1984,797(1):83-93
The 5-hydroxybenzimidazolylcobamide (B12-HBI) derivatives from Methanosarcina barkeri were isolated. SO32?, CN?, H2O, NH3 and CH3? were identified as β-ligands. Two B12-HBI compounds with unidentified β-ligands were found, of which one constituted a major part of the corrinoid content. 5′-Deoxyadenosyl was found as a β-ligand of a corrinoid without α-ligand. Biosynthesis of CH3B12HBI was observed in cell-free extracts and depended on methanol and ATP. 相似文献
2.
Stimulation of CO2 reduction to methane by methylcoenzyme M in extracts Methanobacterium. 总被引:9,自引:0,他引:9
Addition of methyl-coenzyme M (CH3SCH2CH2SO3?) to undialized, anaerobic, cell-extracts of under an atmosphere of H2 and CO2 (80:20 v/v) stimulates 30-fold the rate of CO2 reduction to methane. For each mol of CH3SCH2CH2SO3? added 12 mol of methane is produced. This stimulation phenomenon requires magnesium ion, ATP, H2, and CH3SCH2CH2SO3?. Neither the reduced form of the cofactor, HSCH2CH2SO3?, nor the oxidized, disulfide form will replace the methylated coenzyme. 相似文献
3.
S. V. Bukin O. N. Pavlova G. V. Kalmychkov V. G. Ivanov T. V. Pogodaeva Yu. P. Galach’yants Yu. S. Bukin A. V. Khabuev T. I. Zemskaya 《Microbiology》2018,87(4):549-558
Methane production by microbial communities from Lake Baikal bottom sediments with different chemical composition of pore water was studied. Methane production was more active in the media supplemented with H2: CO2 and H2 + CH3COONa, rather than on media with acetate as the sole source of carbon and energy. Addition of methanol stimulated methane production only in the case of microbial communities from upper silts. Ability of the communities to produce methane correlated reliably with the concentrations of the NO3–, SO42?, Cl–, and CH3COO– ions in the pore water of the relevant sediments. Cultivation of communities from the mud volcano sediments resulted in development of methanogenic archaea of the family Methanocellaсеае in the media supplemented with H2: CO2 and H2 + CH3COONa, while methanogenic archaea in the communities cultivated without additional substrates belonged to the genera Methanoregula, Methanobacterium, and Methanosaeta. 相似文献
4.
A. S. Savvichev I. I. Rusanov N. V. Pimenov E. E. Zakharova E. F. Veslopolova A. Yu. Lein K. Crane M. V. Ivanov 《Microbiology》2007,76(5):603-613
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 × 103 cells ml?1 in the northern and eastern parts to 245 × 103 cells ml?1 in the southern part. The methane content in the water column of the Chukchi sea varied from 8 nmol CH4l?1 in the eastern part of the sea to 31 nmol CH4l?1 in the northern part of the Herald Canyon. Microbial activity occurred in the upper 0–3 cm of the bottom sediments; the methane formation rate varied from 0.25 to 16 nmol CH4dm?3 day?1. The rates of methane oxidation varied from 1.61 to 14.7 nmol CH4dm?3 day?1. The rates of sulfate reduction varied from 1.35 to 16.2 μmol SO 4 2? dm?1 day?1. The rate of methane formation in the sediments increased with depth, while sulfate reduction rates decreased (less than 1 μmol SO 4 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 μmol CH4m?2 day?1. 相似文献
5.
Santosh Ranjan Mohanty Bharati Kollah Vineet K. Sharma Amar Bahadur Singh Muneshwar Singh A. Subba Rao 《Annals of microbiology》2014,64(1):65-74
A laboratory incubation study conducted to assess the temporal variation of CH4 oxidation during soil reduction processes in a flooded soil ecosystem. A classical sequence of microbial terminal electron accepting process observed following NO3 ? reduction, Fe3+ reduction, SO4 2? reduction and CH4 production in flooded soil incubated under initial aerobic and helium-flushed anaerobic conditions. CH4 oxidation in the slurries was influenced by microbial redox process during slurry reduction. Under aerobic headspace condition, CH4 oxidation rate (k) was stimulated by 29 % during 5 days (NO3 ? reduction) and 32 % during both 10 days (Fe3+) and 20 days (early SO4 2? reduction) over unreduced slurry. CH4 oxidation was inhibited at the later methanogenic period. Contrastingly, CH4 oxidation activity in anaerobic incubated slurries was characterized with prolonged lag phase and lower CH4 oxidation. Higher CH4 oxidation rate in aerobically incubated flooded soil was related to high abundance of methanotrophs (r?=?0.994, p?<?0.01) and ammonium oxidizers population (r?=?0.184, p?<?0.05). Effect of electron donors NH4 +, Fe2+, S2? on CH4 oxidation assayed to define the interaction between reduced inorganic species and methane oxidation. The electron donors stimulated CH4 oxidation as well as increased the abundance of methanotrophic microbial population except S2? which inhibited the methanotrophic activity by affecting methane oxidizing bacterial population. Our result confirmed the complex interaction between methane-oxidizing microbial groups and redox species during sequential reduction processes of a flooded soil ecosystem. 相似文献
6.
Various organic sulfides and inorganic sulfide were studied in respect to their effect on growth and methane production of Methanobacterium strain AZ. In mineral, sulfide-free medium, cysteine regulated the specific rate of methane production (optimum concentration =5·10–4 mole/l). A supplement of sulfide (10–4 mole/l) caused an additional stimulation. Coenzyme M** or glutathione could be substituted for cysteine when sulfide was present. Growth was stimulated by CoM and glutathione to the same extent as with cysteine in sulfide-containing media. The concentration of sulfide in cysteine-containing media affected the excretion of amino acids.Abbreviations CoM
Coenzyme M; HS–CH2–CH2–SO3 (Taylor and Wolfe, 1974) 相似文献
7.
Comparisons between in situ CH4 concentration and potential factors controlling its net production were made in a temperate swamp. Seasonal measurements of water table level and depth profiles of pH, dissolved CH4, CO2, O2, SO42-, NO3-, formate, acetate, propionate, and butyrate were made at two adjacent sites 1.5 to 2 m apart. Dissolved CH4 was inversely correlated to O2 and, in general, to NO3- and SO42-, potential inhibitors of methanogenesis. At low water table levels (August 1992), maximal CH4 (2 to 4 μM) occurred below 30 cm, whereas at high water table levels (October 1992) or under flooded conditions (May 1993), CH4 maxima (4 to 55 μM) occurred in the top 10 to 20 cm. Higher CH4 concentrations were likely supported by inputs of fresh organic matter from decaying leaf litter, as suggested by high acetate and propionate concentrations (25 to 100 μM) in one of the sites in fall and spring. Measurements of potential CH4 production (and consumption) showed that the highest rates generally occurred in the top 10 cm of soil. Soil slurry incubations confirmed the importance of organic matter to CH4 production but also showed that competition for substrates by nonmethanogenic microorganisms could greatly attenuate its effect. 相似文献
8.
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10.
Metabolism of Acetate, Methanol, and Methylated Amines in Intertidal Sediments of Lowes Cove, Maine 总被引:14,自引:11,他引:3
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The fates and the rates of metabolism of acetate, trimethylamine, methylamine, and methanol were examined to determine the significance of these compounds as in situ methane precursors in surface sediments of an intertidal zone in Maine. Concentrations of these potential methane precursors were generally <3 μM, with the exception of sediments containing fragments of the seaweed Ascophyllum nodosum, in which acetate was 96 μM. [2-14C]acetate turnover in all samples was rapid (turnover time <2 h), with 14CO2 as the primary product. [14C]trimethylamine and methylamine turnover times were slower (>8 h) and were characterized by formation of both 14CH4 and 14CO2. Ratios of 14CH4/14CO2 from [14C]trimethylamine and methylamine in uninhibited sediments indicated that a significant fraction of these substrates were catabolized via a non-methanogenic process. Data from inhibition experiments involving sodium molybdate and 2-bromoethanesulfonic acid supported this interpretation. [14C]methanol was oxidized relatively slowly compared with the other substrates and was catabolized mainly to 14CO2. Results from experiments with molybdate and 2-bromoethanesulfonic acid suggested that methanol was oxidized primarily through sulfate reduction. In Lowes Cove sediments, trimethylamine accounted for 35.1 to 61.1% of total methane production. 相似文献
11.
《Inorganica chimica acta》1988,141(1):145-149
This contribution reports the synthesis and characterization of the organothorium alkylthiolate complex [(CH3)5C5]2Th(SCH2CH2CH3)2. This compound crystallizes in the monoclinic space group C2/c (#15) with four molecules in a cell of dimensions a=19.066(2), b=11.603(1), c=16.379(2) Å, and β=130.08(1)°. Least-squares refinement led to a value for the conventional R index (on Fo) of 0.040 for 132 variables and 2030 observations having Fo2⩾3σ(Fo2). The molecular structure consists of an unexceptional ‘bent sandwich’ [(CH3)5C5]2Th fragment coordinated to two n-propylthiolate ligands. The ThS bond distance is 2.718(3) Å; the SC(α) distance, 1.78(2) Å; the ThSC(α) angle, 108.3(5)°; and the SThS′ angle, 102.5(2)°. Contrasts are drawn with the structures of analogous actinide alkoxides 相似文献
12.
《Inorganica chimica acta》1986,111(1):73-76
The reaction of the ruthenium complexes RuCl2(PPh3)3, RuCl2(PPh3)4, RuCl2(PMe3)4, RuCl2(Me2SO)4, or RuBr2(PPh3)3 with the tripod tetrakis(tertiary) phosphine P(CH2CH2CH2PMe2)3 gave the compounds cis-RuCl2 [P(CH2CH2CH2PMe2)3] (1) and cis-RuBr2[P(CH2CH2CH2PMe2)3] (2). The coordination geometry of 1 and 2 was derived from the ABX2 type 31P NMR patterns of the complexes, as well as from an X-ray structure determination for the chloride 1. Crystals of 1 were found to be monoclinic, space group P21/n (Z = 4), with a = 942.0(3), b = 1446.2(4), c = 1680(1) pm, and β = 104.99(4)°. Anisotropic refinement of the structure converged at R = 0.040 and Rw = 0.034 (3318 data). Selected bond lengths are (in pm): RuP(CH2−)Me2 (trans-atom P), 235.8(1) and 239.3(1); RuP(CH2−)Me2 (trans-atom Cl), 227.9(1); RuP(CH2−)3, 225.3(1); RuCl (trans-group P(CH2−)3), 252.1(1); and RuCl (trans-group P(CH2)Me2), 250.5(1). Reaction of 1 with LiAlH4 yielded the hydro derivatives cis-Ru(H)Cl[P(CH2CH2CH2PMe2)3] (3) and cis-RuH2[P(CH2CH2CH2PMe2)3] (4), which were characterized by IR and 1H and 31p NMR spectroscopy. 相似文献
13.
Methane emissions from fen,bog and swamp peatlands in Quebec 总被引:8,自引:1,他引:7
A static chamber technique was used weekly from spring thaw to winter freezing to measure methane emissions from 10 sites representing subarctic fens and temperate swamps and bogs. Rates of < 200 mg CH4 m–2 d–1 were recorded in subarctic fens: within-site emissions were primarily controlled by the evolution of the peat thermal regime, though significant releases during spring thaw were recorded at some sites. Between subarctic fens, topography and water table elevation were important controls on methane emissions, with the general sequence: pool = horizontal fen> string. Emission rates from the 2 swamp sites were lower (< 20 mg CH4 m–2 d–1 ), except during the spring thaw and when the sites were saturated. The low water table ( < 80 cm depth) in abnormally dry years reduced emission rates; rates were also low from a swamp site which had been drained and cleared of vegetation for horticulture. Methane emission rates were also low (< 5 mg CH4 m–2 d–1) from 2 ombrotrophic bog sites. Laboratory measurements of rates of methane production under anaerobic conditions and methane consumption under aerobic conditions revealed that production rates were generally highest in the surface layers (0 to 2.5 cm depth); production was high in the fens and very low in the bogs. The swamp samples were able to produce methane under anaerobic conditions, but were also able to consume methane under aerobic conditions. Annual methane emission rates are estimated to be 1 to 10 g CH4 m–2 from the fens, 1 to 4 g CH4 m–2 from the swamps and <0.2 g CH4 m–2 from the bogs and drained swamp. 相似文献
14.
Drainage-induced forest growth alters belowground carbon biogeochemistry in the Mer Bleue bog, Canada 总被引:1,自引:0,他引:1
Impacts of long-term drying and associated vegetation change on anaerobic decomposition, methane production, and pore water composition in peat bogs are poorly documented. To identify some of these impacts, we analyzed peat humification, pore water solutes, in situ and in vitro respiration rates, and Gibbs free energies of methanogenesis in a bog near a drainage ditch established in 1923. We compared drained peat under open bog vegetation and forest with a bog reference site. Drainage and tree growth induced an enrichment in carboxylic, aromatic, and phenolic moieties in the peat. Short-term in vitro respiration rates significantly decreased with humification (R 2?>?0.6, p?<?0.01). Dissolved inorganic carbon (DIC) and CH4 concentrations also attained lower maxima in drained areas. However, near the water table in situ respiration intensified as indicated by steeper increases in DIC and CH4 concentrations than at the reference site, especially under forest. Maximum in situ CO2 production derived from inverse pore water modeling was 10.3?nmol?cm?3?d?1 (forest) and 6.3?nmol?cm-3?d-1 (bog) and was one to two orders of magnitude slower than in vitro anaerobic respiration. In the highly decomposed shallow peats under forest, methane production was suppressed and DOC concentration elevated. Raised H2 concentrations (up to 200?nmol?l?1) and in situ Gibbs free energies of down to ?60?kJ?mol?1?(CH4) suggested an inhibition of hydrogenotrophic methanogenesis by an unidentified factor at these sites. The study documents that several changes in biogeochemical process patterns do occur post-drainage, especially when tree growth is triggered. Most importantly, the establishment of forest on intensely humified peats can lower in situ methane production. 相似文献
15.
Quantification of methane emissions from Chinese rice fields (Zhejiang Province) as influenced by fertilizer treatment 总被引:7,自引:0,他引:7
Reiner Wassmann Helmut Schütz Hans Papen Heinz Rennenberg Wolfgang Seiler Dai Aiguo Shen Renxing Shangguan Xingjian Wang Mingxing 《Biogeochemistry》1993,20(2):83-101
Methane emissions from rice paddies were quantified by using an automatic field system stationed in Zhejiang Province, one
of the centres for rice cultivation in China. The data set showed pronouned interannual variations over 5 consecutive vegetation
periods; by computing average values of all experimental plots the annual emissions were 177 g CH4 m−2 yr−1 in 1987, 50 g CH4 m−2 yr−1 in 1988, and 187 g CH4 m−2 yr−1 in 1989.
The field preparations encompassed 4 different treatments: (1) no fertilizers, (2) mineral fertilizer (KCl, K2SO4), (3) organic manure (rape seeed cake, animal manure), (4) mineral fertilizer plus organic manure. The methane emission rates
of the different fertilizer treatments did not show significant differences. The mean emission rates, calculated over the
entire observation period of 5 seasons, were 30.4 mg CH4 m−2 h−1 (non-fertilized plot) and 28.3 mg CH4 m−2 h−1 (mineral fertilizers). These values indicate a high level of methane production even without additional input of organic
material into the rice-soils. In the other plots, the organic fertilizers were added once per vegetation period at app. 1
t fresh weight per ha, a relatively low application rate by agronomical standards. The mean emission rates were 35.1 mg CH4 m−2 h−1 when manure was applied as sole fertilizer and 27.5 mg CH4 m−2 h−1 when applied jointly with potassium fertilizers.
Based on the results of this study we estimate a range of 18–28 Tg CH4 yr−1 as the total methane emission from Chinese rice fields. However, more field data from representative sites in China are needed
to reduce the uncertainties in this estimate. 相似文献
16.
《Journal of Fermentation Technology》1987,65(4):413-418
Direct conversion of gaseous H2 and CO2 to CH4 was achieved with Methanobacterium thermoautotrophicum ΔH (DSM 1053) cells fixed either on a cellulose acetate membrane or inside a porous silica-alumina ceramic support.In a membrane bioreactor with cellulose acetate (5 μmø), methane production rate increased in proportion to the contact area between the gases and the methanogen cells, giving a methane production rate of 0.75 ml CH4/cm2 contact area/h. The initial fixed-cell mass of 0.2 mg dry cell/cm2 of contact area increased to 1 mg/cm2 after 12 h of cultivation (steady state).In the ceramic bioreactor (cylindrical, 30 mmø × 70; av. pore size 100 μ, and porosity 79.7%), the methane production rate at steady state was 6 l CH4/l ceramic/l. The methanogen cells grew homogeneously inside the ceramic up to 7 cm depth, and the cell density ranged from 20 to 30 mg dry cell/cm3 ceramic. 相似文献
17.
Jeremy M. Berg Keith O. Hodgson Alice E. Bruce James L. Corbin Narayanankutty Pariyadath Edward I. Stiefel 《Inorganica chimica acta》1984,90(1):25-33
The crystal and molecular structures of the complexes MoO2((SCH2CH2)2NCH2CH2SCH3), I and MoO2((SCH2CH2)2NCH2CH2N(CH3)2), II, have been determined from X-ray intensity data collected by counter methods. Compound I crystallizes in two forms, Ia and Ib. In form Ia the space group is P21/n with cell parameters a = 7.235(2), b = 7.717(2), c = 24.527(6) Å, β = 119.86(2)°, V = 1188(1) Å3, Z = 4. In form Ib the space group is P21/c with cell parameters a = 14.945(5), b = 11.925(5), c = 14.878(4) Å, β = 114.51(2)°, V = 2413(3) Å3, Z = 8. The molecules of I in Ia and Ib are very similar having an octahedral structure with cis oxo groups, trans thiolates (cis to both oxo groups) and N and thioether sulfur atoms trans to oxo groups. Average ditances are MoO = 1.70, MoS (thiolate) = 2.40, MoN = 2.40 and MoS (thioether) = 2.79 Å. Molecule II crystallizes in space group P212121 with a = 7.188(1), b = 22.708(8), c = 7.746(2) Å, V = 1246(1) Å3 and Z = 4. The coordination about Mo is octahedral with cis oxo groups, trans thiolates and N atoms trans to oxo. Distances in the first coordination sphere are MoO = 1.705(2), 1.699(2), MoS = 2.420(1), 2.409(1) and MoN = 2.372(2), 2.510(2) Å. The conformational features of the complexes are discussed. Complex I displays MoO and MoS distances which are very similar to those found by EXAFS in sulfite oxidase. This similarity is discussed. 相似文献
18.
Substrates for Sulfate Reduction and Methane Production in Intertidal Sediments 总被引:16,自引:12,他引:4
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The activity of and potential substrates for methane-producing bacteria and sulfate-reducing bacteria were examined in marsh, estuary, and beach intertidal sediments. Slow rates of methane production were detected in all sediments, although rates of sulfate reduction were 100- to 1,000-fold higher. After sulfate was depleted in sediments, the rates of methane production sharply increased. The addition of methylamine stimulated methanogenesis in the presence of sulfate, and [14C]methylamine was rapidly converted to 14CH4 and 14CO2 in freshly collected marsh sediment. Acetate, hydrogen, or methionine additions did not stimulate methanogenesis. [methyl-14C]methionine and [2-14C]acetate were converted to 14CO2 and not to 14CH4 in fresh sediment. No reduction of 14CO2 to 14CH4 occurred in fresh sediment. Molybdate, an inhibitor of sulfate reduction, inhibited [2-14C]acetate metabolism by 98.5%. Fluoracetate, an inhibitor of acetate metabolism, inhibited sulfate reduction by 61%. These results suggest that acetate is a major electron donor for sulfate reduction in marine sediments. In the presence of high concentrations of sulfate, methane may be derived from novel substrates such as methylamine. 相似文献
19.
《Inorganica chimica acta》1986,115(2):147-151
In the presence of Fe3+, template condensation of the fluorinated keto-alcohol CH3C(O)CH2C- (CF3)2OH with the triamine CH3C(CH2NH2)3 leads to two products: a fully condensed, imino-alkoxy, iron(III) complex, Fe{CH3C[CH2NC(CH3)CH2C(CF3)2O]3}, and a partially condensed iron(III) complex, O{FeCH3C[CH2NC(CH3)CH2C(CF3)2O]2(CH2NH2)}2, in which two six-coordinate iron(III) centers are linked by an oxide ion. A complete crystal and molecular structure determination of the latter has been made.Crystals are monoclinic, space group C2/c, a= 13.886(4); b=23.206(5); c=15.241(4) Å; β= 106.55(2)°; V=4708 Å3; Z=4. Least-squares refinement on F of 322 variables using 2627 observations converged at a conventional agreement factor of 3.8%. The Fe to bridging oxide distance is 1.811(1) Å, the FeFe distance 3.468 Å, and the FeOFe angle 146.6(2)°. A comparison is made between this structure and those of natural hemerythrin systems. 相似文献
20.
《Inorganica chimica acta》1987,133(2):295-300
The compound K4[Mo2(SO4)4]Br·4H2O has been made and its crystal structure determined. Space group P4/mnc; unit cell dimensions, a = 11.903(2), c = 8.021(1) Å, V = 1136(1) Å3. The compound is isomorphous with the analogous chloride whose structure has been reported. The MoMo and MoBr distances are 2.169(2) and 2.926(1) Å, respectively and the [Mo2(SO4)4] 3− ions reside on crystallographic special positions with 4/m symmetry. The Raman spectra of both the bromo and chloro compounds have been measured and the MoMo stretching frequency is 370 ± 1.5 cm−1 in each, for the compounds containing the natural isotopic distribution of molybdenum. The chloro compound has been prepared containing the pure isotope 92Mo as well, and the Raman spectra recorded. The v(MoMo) band is shifted by 6.8 ± 0.5 cm−1. The compound K4[Mo2(SO4)4]·2H2O has also been prepared with Mo at natural abundance and with the pure isotope 100Mo, whereby a shift of 8.5 ± 0.5 cm−1 was found. These and other results will be discussed with regard to the similarity of the Raman spectra of the Mo2(S04)43− and M02(S04)44− species. 相似文献