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1.
Shinji Inukai Kazuyoshi Sato Shoichi Shimizu 《Bioscience, biotechnology, and biochemistry》2013,77(11):2229-2234
As a growth factor, Rhizobium meliloti required cobalt ion, or vitamin B12 which was found to be incorporated into the cells without decomposition to cobalt ion. Trial of replacement for cobalt ion by the addition of various compounds to the cobalt-deficient medium revealed that methionine could substitute for cobalt ion and promote the growth in response to its concentration. Furthermore, B12-dependent methionine synthetase was demonstrated in the cell-free extracts of this microorganism. The morphological change of R. meliloti by the additions to the medium was observed microscopically. 相似文献
2.
Rhodopseudomonas acidophila strain 7050 assimilated ammonia via a constitutive glutamine synthetase/glutamate synthase enzyme system.Glutamine synthetase had a K
m
for NH
4
+
of 0.38 mM whilst the nicotinamide adenine dinucleotide linked glutamate synthase had a K
m
for glutamine of 0.55 mM. R. acidophila utilized only a limited range of amino acids as sole nitrogen sources: l-alanine, glutamine and asparagine. The bacterium did not grow on glutamate as sole nitrogen source and lacked glutamate dehydrogenase. When R. acidophila was grown on l-alanine as the sole nitrogen source in the absence of N2 low levels of a nicotinamide adenine dinucleotide linked l-alanine dehydrogenase were produced. It is concluded, therefore, that this reaction was not a significant route of ammonia assimilation in this bacterium except when glutamine synthetase was inhibited by methionine sulphoximine. In l-alanine grown cells the presence of an active alanine-glyoxylate aminotransferase and, on occasions, low levels of an alanine-oxaloacetate aminotransferase were detected. Alanine-2-oxo-glutarate aminotransferase could not be demonstrated in this bacterium.Abreviations ADH
alanine dehydrogenase
- GDH
glutamate dehydrogenase
- GS
glutamine synthetase
- GOGAT
glutamate synthase
- MSO
methionine sulphoximine 相似文献
3.
Kazamia E Czesnick H Nguyen TT Croft MT Sherwood E Sasso S Hodson SJ Warren MJ Smith AG 《Environmental microbiology》2012,14(6):1466-1476
Many algae are auxotrophs for vitamin B12 (cobalamin), which they need as a cofactor for B12‐dependent methionine synthase (METH). Because only prokaryotes can synthesize the cobalamin, they must be the ultimate source of the vitamin. In the laboratory, a direct interaction between algae and heterotrophic bacteria has been shown, with bacteria supplying cobalamin in exchange for fixed carbon. Here we establish a system to study this interaction at the molecular level. In a culture of a B12‐dependent green alga Chlamydomonas nivalis, we found a contaminating bacterium, identified by 16S rRNA analysis as Mesorhizobium sp. Using the sequenced strain of M. loti (MAFF303099), we found that it was able to support the growth of B12‐dependent Lobomonas rostrata, another green alga, in return for fixed carbon. The two organisms form a stable equilibrium in terms of population numbers, which is maintained over many generations in semi‐continuous culture, indicating a degree of regulation. However, addition of either vitamin B12 or a carbon source for the bacteria perturbs the equilibrium, demonstrating that the symbiosis is mutualistic and facultative. Chlamydomonas reinhardtii does not require B12 for growth because it encodes a B12‐independent methionine synthase, METE, the gene for which is suppressed by addition of exogenous B12. Co‐culturing C. reinhardtii with M. loti also results in reduction of METE expression, demonstrating that the bacterium can deliver the vitamin to this B12‐independent alga. We discuss the implications of this for the widespread distribution of cobalamin auxotrophy in the algal kingdom. 相似文献
4.
A morpholinepropanesulfonic acid (MOPS)-buffered rich defined medium (RDM) was optimized to support a reproducible 2.6-h doubling time at 35 °C for Deinococcus radiodurans R1 and used to gain insight into vitamin and carbon metabolism. D. radiodurans was shown to require biotin and niacin for growth in this medium. A glutamine–serine simple defined medium (SDM) was developed that supported a 4-h doubling time, and this medium was used to probe sulfur and methionine metabolism. Vitamin B12 was shown to alleviate methionine auxotrophy, and under these conditions, sulfate was used as the sole sulfur source. Phenotypic characterization of a methionine synthase deletion mutant demonstrated that the B12 alleviation of methionine auxotrophy was due to the necessity of the B12-dependent methionine synthase in methionine biosynthesis. Growth on ammonium as the sole nitrogen source in the presence of vitamin B12 was demonstrated, but it was not possible to achieve reproducibly good growth in the absence of at least one amino acid as a nitrogen source. Growth on sulfate, cysteine, and methionine as sulfur sources demonstrated the function of a complete sulfur recycling pathway in this strain. These studies have demonstrated that rapid growth of D. radiodurans R1 can be achieved in a MOPS-based medium solely containing a carbon source, salts, four vitamins, and two amino acids. 相似文献
5.
Katsuhiko Fujii Hisao Takeuchi Shoichi Shimizu Saburo Fukui 《Bioscience, biotechnology, and biochemistry》2013,77(13):2323-2334
A vitamin B12-dependent N5-methyltetrahydrofoIate-homocysteine methyltransferase was found in cell-free extracts of Corynebacterium simplex ATCC 6946 grown aerobically in a medium containing hydrocarbon as a sole carbon source and the enzyme was partially purified. Absolute requirements for S-adenosylmethionine and an appropriate reducing system were observed for the transmethylation from N5-methyltetrahydrofolate. The same preparation catalyzed also the formation of methionine from homocysteine and methyl-B12 under both aerobic and anaerobic conditions. The concentration of cobalt ion in the growth medium had a pronounced effect on the intracellular vitamin B12 level and the activity of the vitamin-dependent methionine-synthesizing system in the bacterium. The relationship between the methionine synthesis and the methyl branched-chain fatty acid formation was discussed. 相似文献
6.
Atsuhiko Ishida Hirokazu Kanefusa Hidenori Fujita Tetsuo Toraya 《Archives of microbiology》1994,161(4):293-299
Novel vitamin B12 analogues in which the D-ribose moiety of the nucleotide loop was replaced by an oligomethylene group and a trimethylene analogue containing imidazole instead of 5,6-dimethylbenzimidazole as well as cobinamide methyl phosphate were tested for biological activities with Escherichia coli 215, a B12- or methionine-auxotroph, and Lactobacillus leichmannii ATCC 7830 as test organisms. A cyano form of 5,6-dimethylbenzimidazolyl tetramethylene, trimethylene and hexamethylene analogues supported the growth of L. leichmannii in this order. 5.6-Dimethylbenzimidazolyl dimethylene and imidazolyl trimethylene analogues did not show B12 activity and behaved as weak B12 antagonists when added together with cyanocobalamin. An adenosyl form of the biologically active analogues served as coenzymes for ribonucleotide reductase of this bacterium, whereas that of the inactive analogues did not. The latter acted as weak competitive inhibitors against adenosylcobalamin. ON the contrary, all the analogues did not support the growth of E. coli 215 at all by themselves and inhibited the growth when added with a suboptimum level of cyanocobalamin. A methyl form of the analogues also did not support the growth of E. coli 215, although they served as active coenzymes for methionine synthase of the bacterium. Since unlabeled analogues strongly inhibited the uptake of [3H]cyanocobalamin by this bacterium, it seems likely that the analogues exert their anti-B12 activity toward E. coli 215 by blocking the B12-transport systemAbbreviations AdoCbl
adenosylcobalamin
- MeCbl
methylcobalamin
- CN-Cbl
cyanocobalamin or vitamin B12
- Cbl
cobalamin
- (CN, aq)Cbi
cyanoaquacobinamide
- MeCbi
methylcobinamide
- Cbi
cobinamide
- (CN, aq)Cbi-PMe
cyanoaquacobinamide methyl phosphate
- Cbi-PMe
cobinamide methyl phosphate
- DBI
5,6-dimethylbenzimidazole
- DBIyl
5,6-dimethylbenzimidazolyl
- FMNH2
fully reduced form of riboflavin 5-phosphate 相似文献
7.
ATPases with unusual membrane-embedded rotor subunits were found in both F1F0 and A1A0 ATP synthases. The rotor subunit c of A1A0 ATPases is, in most cases, similar to subunit c from F0. Surprisingly, multiplied c subunits with four, six, or even 26 transmembrane spans have been found in some archaea and these multiplication events were
sometimes accompanied by loss of the ion-translocating group. Nevertheless, these enzymes are still active as ATP synthases.
A duplicated c subunit with only one ion-translocating group was found along with “normal” F0 c subunits in the Na+ F1F0 ATP synthase of the bacterium Acetobacterium woodii. These extraordinary features and exceptional structural and functional variability in the rotor of ATP synthases may have
arisen as an adaptation to different cellular needs and the extreme physicochemical conditions in the early history of life. 相似文献
8.
The mechanism of acetate assimilation by the purple nonsulfur bacterium Rhodobacter sphaeroides, which lacks the glyoxylate shunt, has been studied. In a previous work, proceeding from data on acetate assimilation by Rba. sphaeroides cell suspensions, a suggestion was made regarding the operation, in this bacterium, of the citramalate cycle. This cycle was earlier found in Rhodospirillum rubrum in the form of an anaplerotic reaction sequence that operates during growth on acetate instead of the glyoxylate shunt, which is not present in the latter bacterium. The present work considers the enzymes responsible for acetate assimilation in Rba. sphaeroides. It is shown that this bacterium possesses the key enzymes of the citramalate cycle: citramalate synthase, which catalyzes condensation of acetyl-CoA and pyruvate and, as a result, forms citramalate, and 3-methylmalyl-CoA lyase, which catalyzes the cleavage of 3-methylmalyl-CoA to glyoxylate and propionyl-CoA. The regeneration of pyruvate, which is the acetyl-CoA acceptor in the citramalate cycle, involves propionyl- CoA and occurs via the following reaction sequence: propionyl-CoA (+CO2) å methylmalonyl-CoA å succinyl-CoA å succinate å fumarate malate å oxaloacetate (−CO2) å phosphoenolpyruvate å pyruvate. The independence of the cell growth and the acetate assimilation of CO2 is due to the accumulation of CO2/HCO
3
−
(released during acetate assimilation) in cells to a level sufficient for the effective operation of propionyl-CoA carboxylase.__________Translated from Mikrobiologiya, Vol. 74, No. 3, 2005, pp. 319–328.Original Russian Text Copyright © 2005 by Filatova, Berg, Krasil’nikova, Ivanovsky. 相似文献
9.
Hitoshi Murata 《Mycoscience》1999,40(1):81-85
A brown blotch bacterium,Pseudomonas tolaasii strain PT814, expresses a high degree of cross-protection against generalized stress imposed by physical/chemical treatment,
H2O2, UV, high temperature, ethanol and NaCl during the interaction withPleurotus ostreatus. Stress resistance was also noted in the bacterium in vitro under limited carbon and nitrogen sources. In addition, changes
in cell morphology from a “metabolically active” rod to an “energy-saving” spherical shape were detected during starvation
and the interaction. All the changes under stress were reversible. A homologue ofrpoS (σ
S), a regulator that controls such physiological status during starvation in other bacteria, was identified inP. tolaasii strain PT814. Data suggest that the bacterium is able to withstand a complex stress environment for its survival through
changes in its metabolic pattern. 相似文献
10.
Steffen Fehrmann Hélène Bottin‐Duplus Andri Leonidou Esther Mollereau Audrey Barthelaix Wu Wei Lars M Steinmetz Gaël Yvert 《Molecular systems biology》2013,9(1)
Living systems may have evolved probabilistic bet hedging strategies that generate cell‐to‐cell phenotypic diversity in anticipation of environmental catastrophes, as opposed to adaptation via a deterministic response to environmental changes. Evolution of bet hedging assumes that genotypes segregating in natural populations modulate the level of intraclonal diversity, which so far has largely remained hypothetical. Using a fluorescent Pmet17‐GFP reporter, we mapped four genetic loci conferring to a wild yeast strain an elevated cell‐to‐cell variability in the expression of MET17, a gene regulated by the methionine pathway. A frameshift mutation in the Erc1p transmembrane transporter, probably resulting from a release of laboratory strains from negative selection, reduced Pmet17‐GFP expression variability. At a second locus, cis‐regulatory polymorphisms increased mean expression of the Mup1p methionine permease, causing increased expression variability in trans. These results demonstrate that an expression quantitative trait locus (eQTL) can simultaneously have a deterministic effect in cis and a probabilistic effect in trans. Our observations indicate that the evolution of transmembrane transporter genes can tune intraclonal variation and may therefore be implicated in both reactive and anticipatory strategies of adaptation. 相似文献
11.
Youn Hong Jung Ji-Yeun Yi Hyun Jung Jung Yoo Kyung Lee Hong Kum Lee Mahendran Chinnamara Naicker Ji-hyun Uh I Seul Jo Eun Jung Jung Hana Im 《The protein journal》2010,29(2):136-142
A polar bacterium was isolated from Arctic sea sediments and identified as Psychromonas artica, based on 16S rDNA sequence. Psychromonas artica KOPRI 22215 has an optimal growth temperature of 10 °C and a maximum growth temperature of 25 °C, suggesting this bacterium
is a psychrophile. Cold shock proteins (Csps) are induced upon temperature downshift by more than 10 °C. Functional studies
have researched mostly Csps of a mesophilic bacterium Escherichia coli, but not on those of psychrophilic bacteria. In an effort to understand the molecular mechanisms of psychrophilic bacteria
that allow it withstand freezing environments, we cloned a gene encoding a cold shock protein from P. artica KOPRI 22215 (CspAPa) using the conserved sequences in csp genes. The 204 bp-long ORF encoded a protein of 68 amino acids, sharing 56% homology to previously reported E. coli CspA protein. When CspAPa was overexpressed in E. coli, it caused cell growth-retardation and morphological elongation. Interestingly, overexpression of CspAPa drastically increased the host’s cold-resistance by more than ten times, suggesting the protein aids survival in polar environments. 相似文献
12.
Halomethane:Bisulfide/Halide Ion Methyltransferase, an Unusual Corrinoid Enzyme of Environmental Significance Isolated from an Aerobic Methylotroph Using Chloromethane as the Sole Carbon Source 总被引:4,自引:4,他引:0
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Catherine Coulter John T. G. Hamilton W. Colin McRoberts Leonid Kulakov Michael J. Larkin David B. Harper 《Applied microbiology》1999,65(10):4301-4312
A novel dehalogenating/transhalogenating enzyme, halomethane:bisulfide/halide ion methyltransferase, has been isolated from the facultatively methylotrophic bacterium strain CC495, which uses chloromethane (CH3Cl) as the sole carbon source. Purification of the enzyme to homogeneity was achieved in high yield by anion-exchange chromatography and gel filtration. The methyltransferase was composed of a 67-kDa protein with a corrinoid-bound cobalt atom. The purified enzyme was inactive but was activated by preincubation with 5 mM dithiothreitol and 0.5 mM CH3Cl; then it catalyzed methyl transfer from CH3Cl, CH3Br, or CH3I to the following acceptor ions (in order of decreasing efficacy): I−, HS−, Cl−, Br−, NO2−, CN−, and SCN−. Spectral analysis indicated that cobalt in the native enzyme existed as cob(II)alamin, which upon activation was reduced to the cob(I)alamin state and then was oxidized to methyl cob(III)alamin. During catalysis, the enzyme shuttles between the methyl cob(III)alamin and cob(I)alamin states, being alternately demethylated by the acceptor ion and remethylated by halomethane. Mechanistically the methyltransferase shows features in common with cobalamin-dependent methionine synthase from Escherichia coli. However, the failure of specific inhibitors of methionine synthase such as propyl iodide, N2O, and Hg2+ to affect the methyltransferase suggests significant differences. During CH3Cl degradation by strain CC495, the physiological acceptor ion for the enzyme is probably HS−, a hypothesis supported by the detection in cell extracts of methanethiol oxidase and formaldehyde dehydrogenase activities which provide a metabolic route to formate. 16S rRNA sequence analysis indicated that strain CC495 clusters with Rhizobium spp. in the alpha subdivision of the Proteobacteria and is closely related to strain IMB-1, a recently isolated CH3Br-degrading bacterium (T. L. Connell Hancock, A. M. Costello, M. E. Lidstrom, and R. S. Oremland, Appl. Environ. Microbiol. 64:2899–2905, 1998). The presence of this methyltransferase in bacterial populations in soil and sediments, if widespread, has important environmental implications. 相似文献
13.
Summary The chemical composition of cell walls from choline-less Torulopsis pintolopesii grown with choline or with methionine was studied. Methioninegrown cells synthesized a weakened cell wall compared to normal choline-grown yeast. The ethylenediamine fractionation procedure yielded three fractions—A, B, and C—with different solubilities. Glucose and mannose were detected in hydrolysed unfractionated cell walls from yeasts grown under both conditions as well as in all fractions. Glucose content was greater in fractions B and C from methioninegrown cells; the mannose content was about the same. Walls from choline-grown cells (W
c
) had 25% more protein than walls from methionine-grown cells (W
m
). The amino acid composition of the proteins of W
c
and W
m
was not qualitatively altered. Seventeen amino acids were identified; glutamic and aspartic acids and valine predominated. W
c
had 3.5 times more lipid than W
m
. The amount of phosphorus was the same. Yeasts grown on methionine synthesized more ergosterol than choline-grown cells. The rate of formation of spheroplasts was higher in methionine-grown cells. Rates of incorporation of adenine, glutamic acid, and uracil were similar in cells grown on methionine or choline; incorporation of phenylalanine and tyrosine was depressed in methionine-grown cells. 相似文献
14.
Taeko Yoshinaka Keiji Yano Hikoyuki Yamaguchi 《Bioscience, biotechnology, and biochemistry》2013,77(10):2269-2275
A highly γ-ray resistant bacterium, which has not been described hitherto, has been isolated from water containing mud, fur and moss at a radioactive hot spring, Misasa, Tottori Prefecture, Japan, This bacterium was Gram-positive, non-sporulating, pink to red colored and pleomorphic rod at young stage and predominantly coccoid or small short rod at old. The radiosensitivity of this bacterium was lower than that of well-known bacterium Micrococcus radio- durans. When its exponentially growing cells were irradiated in buffer solution aerated sufficiently at room temperature, shoulder dose and D0 were calculated to be 6 × 105 and 1 × 106 rads, respectively. The morphological, cultural and physiological characteristics of the bacterium have been studied. These attributes suggested that the organism was a new species, and the name Arthrobacter radiotolerans has been assigned with respect to its high radioresistance. 相似文献
15.
A strain D3 of denitrifying bacterium was isolated from an anammox reactor,and identi-fied as Pseudomonas mendocina based on the morphological and physiological assay,Vitek test,Biolog test,(G C) mol% content,and 16S rDNA phylogenetic analysis.As a typical denitrifying bac-terium,strain D3 achieved the maximal nitrate reduction rate of 26.2 mg/(L·d) at the nitrate concen-tration of 88.5 mg N/L.The optimal pH and growth temperature were 7.84 and 34.9℃,respectively.Strain D3 was able to oxidize ammonia under anaerobic condition.The maximum nitrate and ammo-nium utilization rates were 6.37 mg/(L·d) and 3.34 mg/(L·d) ,respectively,and the consumption ratio of ammonia to nitrate was 1:1.91.Electron microscopic observation revealed peculiar cell inclusions in strain D3.Because of its relation to anammox activity,strain D3 was presumed to be anammoxosome.The present investigation proved that denitrifying bacteria have the anammox ability,and the results have engorged the range of anammox populations. 相似文献
16.
Identification of a denitrifying bacterium and verification of its anaerobic ammonium oxidation ability 总被引:1,自引:0,他引:1
A strain D3 of denitrifying bacterium was isolated from an anammox reactor, and identified as Pseudomonas mendocina based on the morphological and physiological assay, Vitek test, Biolog test, (G+C) mol% content, and 16S rDNA phylogenetic
analysis. As a typical denitrifying bacterium, strain D3 achieved the maximal nitrate reduction rate of 26.2 mg/(L·d) at the nitrate concentration of 88.5 mg N/L. The optimal pH
and growth temperature were 7.84 and 34.9°C, respectively. Strain D3 was able to oxidize ammonia under anaerobic condition. The maximum nitrate and ammonium utilization rates were 6.37 mg/(L·d)
and 3.34 mg/(L·d), respectively, and the consumption ratio of ammonia to nitrate was 1:1.91. Electron microscopic observation
revealed peculiar cell in clusions in strain D3. Because of its relation to anammox activity, strain D3 was presumed to be anammoxosome. The present investigation proved that denitrifying bacteria have the anammox ability, and
the results have engorged the range of anammox populations. 相似文献
17.
Expression of the Bacillus thuringiensis Mosquitocidal Toxin Cry11Aa in the Aquatic Bacterium Asticcacaulis excentricus 总被引:2,自引:0,他引:2
A mosquitocidal aquatic bacterium has been developed by introducing an operon containing the cry11Aa, and p20 genes from Bacillus thuringiensis subsp. israelensis (Bti) into the gram-negative aquatic bacterium Asticcacaulis excentricus. After transformation, the cry11Aa gene was successfully expressed in recombinant A. excentricus under the tac promoter, at the level of 0.04 pg/cell. The recombinant bacteria were toxic to Aedes aegypti larvae with an LC50 of 6.83 × 105 cells/mL. We believe that these bacteria may have potential as genetically engineered microorganisms for the control of mosquito
larvae. 相似文献
18.
Monique Barel Karin Meibom Iharilalao Dubail Joaquin Botella Alain Charbit 《Cellular microbiology》2012,14(11):1769-1783
Francisella tularensis, a Gram‐negative bacterium that causes the disease tularemia in a large number of animal species, is thought to reside preferentially within macrophages in vivo. F. tularensis has developed mechanisms to rapidly escape from the phagosome into the cytoplasm of infected cells, a habitat with a rich supply of nutrients, ideal for multiplication. SLC1A5 is a neutral amino acid transporter expressed by human cells, which serves, along with SLC7A5 to equilibrate cytoplasmic amino acid pools. We herein analysed whether SLC1A5 was involved in F. tularensis intracellular multiplication. We demonstrate that expression of SLC1A5 is specifically upregulated by F. tularensis in infected THP‐1 human monocytes. Furthermore, we show that SLC1A5 downregulation decreases intracellular bacterial multiplication, supporting the involvement of SLC1A5 in F. tularensis infection. Notably, after entry of F. tularensis into cells and during the whole infection, the highly glycosylated form of SLC1A5 was deglycosylated only by bacteria capable of cytosolic multiplication. These data suggest that intracellular replication of F. tularensis depends on the function of host cell SLC1A5. Our results are the first, which show that Francisella intracellular multiplication in human monocyte cytoplasm is associated with a post‐translational modification of a eukaryotic amino acid transporter. 相似文献
19.
A mesophilic bacterium capable of utilizing acrylamide was isolated, AUM-01, from soil collected from leaf litter at Picnic
Point on the UW-Madison campus. In minimal medium with acrylamide as the sole carbon and nitrogen source, a batch culture
of AUM-01 completely converted 28.0 mM acrylamide to acrylic acid in 8 h and reached a cell density of 0.3 (A600). Afterward all the acrylic acid was degraded by 20 h with the cell density increasing to 1.9 (A600). The acrylamide-utilizing bacterium was identified as Ralstonia eutropha based on morphological observations, the BiOLOG GN2 MicroPlateTM identification system for Gram-negative bacteria, and additional physiological tests. An acrylamidase that hydrolyzes acrylamide
to acrylic acid was purified from the strain AUM-01. The molecular weight of the enzyme from AUM-01 was determined to be 38 kDa
by SDS–PAGE. The enzyme had pH and temperature optima of 6.3 and 55°C, and the influence of different metals and amino acids
on the ability of the purified protein to transform acrylamide to acrylic acid was evaluated. The enzyme from AUM-01 was totally
inhibited by ZnSO4 and AgNO3. 相似文献
20.
A new, obligately methylotrophic, methane-oxidizing bacterium, strain AMO 1, was isolated from a mixed sample of sediments
from five highly alkaline soda lakes (Kenya). Based on its cell ultrastructure and high activity of the hexulose-6-phosphate
synthase, the new isolate belongs to the type I methanotrophs. It differed, however, from the known neutrophilic methanotrophs
by the ability to grow and oxidize methane at high pH values. The bacterium grew optimally with methane at pH 9–10. The oxidation
of methane, methanol, and formaldehyde was optimal at pH 10, and cells were still active up to pH 11. AMO 1 was able to oxidize
ammonia to nitrite at high pH. A maximal production of nitrite from ammonia in batch cultures at pH 10 was observed with 10%
of CH4 in the gas phase when nitrate was present as nitrogen source. Washed cells of AMO 1 oxidized ammonia most actively at pH
10–10.5 in the presence of limiting amounts of methanol or CH4. The bacterium was also capable of oxidizing organic sulfur compounds at high pH. Washed cells grown with methane exhibited
high activity of CS2 oxidation and low, but detectable, levels of DMS and DMDS oxidation. The GC content of AMO 1 was 50.9 mol%. It showed only
weak DNA homology with the previously described alkaliphilic methanotroph "Methylobacter alcaliphilus" strain 20 Z and with the neutrophilic species of the genera Methylobacter and Methylomonas. According to the 16S rRNA gene sequence analysis, strain AMO 1 was most closely related to a neutrophilic methanotroph, Methylomicrobium pelagicum (98.2% sequence similarity), within the gamma-Proteobacteria.
Received: July 26, 1999 / Accepted: January 4, 2000 相似文献