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1.
Aeromonas hydrophila ATCC 7966 grew anaerobically on glycerol with nitrate, fumarate, Fe(III), Co(III), or Se(VI) as the sole terminal electron
acceptor, but did not ferment glycerol. Final cell yields were directly proportional to the amount of terminal electron acceptor
provided. Twenty-four estuarine mesophilic aeromonads were isolated; all reduced nitrate, Fe(III), or Co(III), and five strains
reduced Se(VI). Dissimilatory Fe(III) reduction by A. hydrophila may involve cytochromes. Difference spectra obtained with whole cells showed absorption maxima at wavelengths characteristic
of c-type cytochromes (419, 522, and 553 nm). Hydrogen-reduced cytochromes within intact cells were oxidized by the addition of
Fe(III) or nitrate. Studies with respiratory inhibitors yielded results consistent with a respiratory chain involving succinate
(flavin-containing) dehydrogenase, quinones and cytochromes, and a single Fe(III) reductase. Neither anaerobic respiration
nor dissimilatory metal reduction by members of the genus Aeromonas have been reported previously.
Received: 24 June 1997 / Accepted: 20 October 1997 相似文献
2.
Microbial Metabolism of Benzene and the Oxidation of Ferrous Iron under Anaerobic Conditions: Implications for Bioremediation 总被引:1,自引:0,他引:1
Benzene and toluene were biodegraded when chelated Fe(III) served as the terminal electron acceptor in aquifer sediments contaminated by a petroleum refinery. Benzene biodegradation ceased when Fe(III) was depleted but resumed upon reamendment. Microorganisms from the same sediments degraded toluene, but not benzene, under nitrate reducing conditions. However, the anaerobic oxidation of Fe(II) to Fe(III) was also observed in toluene-degrading incubations. Fe(II) oxidation was dependent on the presence of nitrate and enhanced when organic electron donors were provided. Microbial nitrate-linked Fe(II) oxidation was also documented in other petroleum-contaminated aquifer sediments, sludge from an oil–water separator, a landfill leachate-impacted aquifer and a garden soil. These observations suggest that some of the reported effects of nitrate on hydrocarbon biodegradation may be indirect through the reoxidation of Fe(II). 相似文献
3.
Geovibrio ferrireducens,a phylogenetically distinct dissimilatory Fe(III)-reducing bacterium 总被引:1,自引:0,他引:1
F. Caccavo Jr. John D. Coates Ramon A. Rossello-Mora Wolfgang Ludwig Karl Heinz Schleifer Derek R. Lovley Michael J. McInerney 《Archives of microbiology》1996,165(6):370-376
A new, phylogenetically distinct, dissimilatory, Fe(III)-reducing bacterium was isolated from surface sediment of a hydrocarbon-contaminated
ditch. The isolate, designated strain PAL-1, was an obligately anaerobic, non-fermentative, motile, gram-negative vibrio.
PAL-1 grew in a defined medium with acetate as electron donor and ferric pyrophosphate, ferric oxyhydroxide, ferric citrate,
Co(III)-EDTA, or elemental sulfur as sole electron acceptor. PAL-1 also used proline, hydrogen, lactate, propionate, succinate,
fumarate, pyruvate, or yeast extract as electron donors for Fe(III) reduction. It is the first bacterium known to couple the
oxidation of an amino acid to Fe(III) reduction. PAl-1 did not reduce oxygen, Mn(IV), U(VI), Cr(VI), nitrate, sulfate, sulfite,
or thiosulfate with acetate as the electron donor. Cell suspensions of PAL-1 exhibited dithionite-reduced minus air-oxidized difference spectra that were characteristic of c-type cytochromes. Analysis of the 16S rRNA gene sequence of PAL-1 showed that the strain is not related to any of the described
metal-reducing bacteria in the Proteobacteria and, together with Flexistipes sinusarabici, forms a separate line of descent within the Bacteria. Phenotypically and phylogenetically, strain PAl-1 differs from all other
described bacteria, and represents the type strain of a new genus and species, Geovibrio
ferrireducens.
Received: 26 September 1995 / Accepted: 28 February 1996 相似文献
4.
5.
Ultraviolet light sensitive mutants of Coprinus lagopus. I. Isolation and characterization 总被引:2,自引:0,他引:2
4UV-sensitive mutants have been isolated from the wild type strain BC9/66 of Coprinus lagopus by following a new replica plating technique. Complementation and recombination studies between these mutants suggest 3 gene loci uvs1, uvs2 and uvs3, two of the mutants being allelic (uvs3-1 and uvs3-2). The mutants uvs2, uvs3-1 and uvs3-2 show photoreactivation whereas the mutant uvs1 appears to be deficient in this respect. None of the mutants of the wild type showed significant recovery after dark holding. 相似文献
6.
The reduction of Cr(VI) at the expense of molecular hydrogen was studied using resting cells of Desulfovibrio vulgaris ATCC 29579 in anaerobic resting cell suspensions in MOPS buffer. Bioreduction occurred only in the presence of ligands or chelating agents (CO32-, citrate, NTA, EDTA, DTPA). The stimulatory effect of these ligands on the rate of Cr(VI) reduction was correlated (r = 0.988) with the strength of the ligand/chelate complex of Cr(III). The data are examined with respect to likely solution and redox equilibria in the ionic matrix of the carrier solution, and with respect to the potential for bioremediation of Cr(VI). 相似文献
7.
8.
Chernyh NA Gavrilov SN Sorokin VV German KE Sergeant C Simonoff M Robb F Slobodkin AI 《Applied microbiology and biotechnology》2007,76(2):467-472
Washed cell suspensions of the anaerobic hyperthermophilic archaea Thermococcus pacificus and Thermoproteus uzoniensis and the anaerobic thermophilic gram-positive bacteria Thermoterrabacterium ferrireducens and Tepidibacter thalassicus reduced technetium [99Tc(VII)], supplied as soluble pertechnetate with molecular hydrogen as an electron donor, forming highly insoluble Tc(IV)-containing
grayish-black precipitate. Apart from molecular hydrogen, T. ferrireducens reduced Tc(VII) with lactate, glycerol, and yeast extract as electron donors, and T. thalassicus reduced it with peptone. Scanning electron microscopy and X-ray microanalysis of cell suspensions of T. ferrireducens showed the presence of Tc-containing particles attached to the surfaces of non-lysed cells. This is the first report on the
reduction in Tc(VII) by thermophilic microorganisms of the domain Bacteria and by archaea of the phylum Euryarchaeota. 相似文献
9.
Out of nineteen bacteria screened from the tannery waste dump site, the most effective isolate, strain DU17 was selected for Cr(VI) reduction process among the non-pathogenic once. Based on 16S rRNA gene sequence analysis, the bacterium was identified as Enterobacter sp. DU17. Its amplified Cr(VI) reductase gene showed maximum homology with flavoprotein of Enterobacter cloacae. Enterobacter sp. DU17 reduced Cr(VI) maximally at 37 °C and pH 7.0. Various co-metals, electron (e−) donors and inhibitors were tested to study their effect on Cr(VI) reduction. In presence (0.2% each) of glucose and fructose, Enterobacter sp. DU17 reduced Cr(VI) completely after 16 and 20 h, respectively. Since the concentration of total Cr was invariable after remediation as detected through AAS analysis, this experiment disclosed that responsible operation was associated with extracellular Cr(VI) reduction process rather than uptake mechanism. Multiple antibiotic resistance index of 0.08 for this bacterium was very low as compared to standard risk assessment value of 0.20. With high Cr(VI) reducing capability, non-pathogenicity and antibiotic sensitivity, Enterobacter sp. DU17 is found to be very efficient in removing Cr(VI) toxicity from the environment. 相似文献
10.
D R Lovley 《Journal of industrial microbiology & biotechnology》1997,18(2-3):75-81
Laboratory incubations of aquifer material or enrichments derived from aquifer material as well as geochemical data have
suggested that, under the appropriate conditions, BTEX components of petroleum (benzene, toluene, ethylbenzene and xylene)
can be degraded in the absence of molecular oxygen with either Fe(III), sulfate, or nitrate serving as the electron acceptor.
BTEX degradation under methanogenic conditions has also been observed. However, especially for benzene, the BTEX contaminant
of greatest concern, anaerobic degradation is often difficult to establish and maintain in laboratory incubations. Although
studies to date have suggested that naturally occurring anaerobic BTEX degradation has the potential to remove significant
quantities of BTEX from petroleum-contaminated aquifers, and mechanisms for stimulating anaerobic BTEX degradation in laboratory
incubations have been developed, further study of the organisms involved in this metabolism and the factors controlling their
distribution and activity are required before it will be possible to design rational strategies for accelerating anaerobic
BTEX degradation in contaminated aquifers.
Received 21 November 1995/ Accepted in revised form 20 February 1996 相似文献
11.
Ethylene production,cluster root formation,and localization of iron(III) reducing capacity in Fe deficient squash roots 总被引:1,自引:1,他引:0
Dicots and non-graminaceous monocots have the ability to increase root iron(III) reducing capacity in response to iron (Fe)
deficiency stress. In squash (Cucurbita pepo L.) seedlings, Fe(III) reducing capacity was quantified during early vegetative growth. When plants were grown in Fe-free
solution, the Fe(III) reducing capacity was greatly elevated, reached peak activity on day 4, then declined through day 6.
Root ethylene production exhibited a temporal pattern that closely matched that of Fe(III) reducing capacity through day 6.
On the 7th day of Fe deficiency, cluster root morphology developed, which coincided with a sharp increase in the root Fe(III)
reducing capacity, although ethylene production decreased. Localization of Fe(III) reducing capacity activity was observed
during the onset of Fe deficiency and through the development of the root clusters. It was noted that localization shifted
from an initial pattern which occurred along the main and primary lateral root axes, excluding the apex, to a final localization
pattern in which the reductase appeared only on secondary laterals and cluster rootlets.
This revised version was published online in June 2006 with corrections to the Cover Date. 相似文献
12.
Hans Löw Frederick L. Crane Eric J. Partick Glen S. Patten Michael G. Clark 《Biochimica et Biophysica Acta (BBA)/Molecular Cell Research》1984,804(2):253-260
Ferricyanide was reduced to ferrocyanide by the perfused rat heart at a linear rate of 78 nmol/min per g of heart (non-recirculating mode). Ferricyanide was not taken up by the heart and ferrocyanide oxidation was minimal (3 nmol/min per g of heart). Perfusate samples from hearts perfused without ferricyanide did not reduce ferricyanide. A single high-affinity site (apparent Km=22 μM) appeared to be responsible for the reduction. Perfusion of the heart with physiological medium containing 0.5 mM ferricyanide did not alter contractility, biochemical parameters or energy status of the heart. Perfusate flow rate and perfusate oxygen concentration exerted opposing effects on the rate of ferricyanide reduction. A net decreased reduction rate resulted from a decreased perfusion flow rate. Thus, the rate of supply of ferricyanide dominated over the stimulatory effect of oxygen restriction; the latter effect only becoming apparent when the oxygen concentration was lowered at a high perfusate flow rate. Whereas glucose (5 mM) increased the rate of ferricyanide reduction, pyruvate (2 mM), acetate (2 mM), lactate (2 mM) and 3-hydroxybutyrate (2 mM) each had no effect. Insulin (3 nM), glucagon (0.5 μM), dibutyryl cyclic AMP (0.1 mM) and the β-adrenergic agonist ritodrine (10 μM) also had no effect, however the α1-adrenergic agonist, methoxamine (10 μM), produced a net increase in the rate of ferricyanide reduction. It is concluded that a trans-plasma membrane electron efflux occurs in perfused rat heart that is sensitive to oxygen supply, glucose, perfusion flow rate, and the α-adrenergic agonist methoxamine. 相似文献
13.
[背景] 异化铁还原细菌能够在还原Fe (III)的同时将毒性较大的Cr (VI)还原成毒性较小的Cr (III),解决铬污染的问题。[目的] 基于丁酸梭菌(Clostridium butyricum) LQ25异化铁还原过程制备生物磁铁矿,开展异化铁还原细菌还原Cr (VI)的特性研究。[方法] 构建以氢氧化铁为电子受体和葡萄糖为电子供体的异化铁培养体系。菌株LQ25培养结束时制备生物磁铁矿。设置不同初始Cr (VI)浓度(5、10、15、25和30 mg/L),分别测定菌株LQ25对Cr (VI)还原效率以及生物磁铁矿对Cr (VI)的还原效率。[结果] 菌株LQ25在设置的Cr (VI)浓度范围内都能良好生长。当Cr (VI)浓度为15 mg/L时,在异化铁培养条件下,菌株LQ25对Cr (VI)的还原率为63.45%±5.13%,生物磁铁矿对Cr (VI)的还原率为87.73%±9.12%,相比菌株还原Cr (VI)的效率提高38%。pH变化能影响生物磁铁矿对Cr (VI)的还原率,当pH 2.0时,生物磁铁矿对Cr (VI)的还原率最高,几乎达到100%。电子显微镜观察发现生物磁铁矿表面有许多孔隙,X-射线衍射图谱显示生物磁铁矿中Fe (II)的存在形式是Fe (OH)2。[结论] 基于异化铁还原细菌制备生物磁铁矿可用于还原Cr (VI),这是一种有效去除Cr (VI)的途径。 相似文献
14.
Thermophilic Microbial Metal Reduction 总被引:1,自引:0,他引:1
A. I. Slobodkin 《Microbiology》2005,74(5):501-514
Thermophilic microorganisms can reduce Fe(III), Mn(IV), Cr(VI), U(VI), Tc(VII), Co(III), Mo(VI), Au(I, III), and Hg(II). Ferric iron and Mn(IV) can be used as electron acceptors during growth; the physiological role of the reduction of the other metals is unclear. The process of microbial dissimilatory reduction of Fe(III) is the most thoroughly studied. Iron-reducing prokaryotes have been found in virtually all of the recognized types of terrestrial ecosystems, from hot continental springs to geothermally heated subsurface sediments. Thermophilic iron reducers do not belong to a phylogenetically homogenous group and include representatives of many bacterial and archaeal taxa. Iron reducing thermophiles can couple Fe(III) reduction with oxidation of a wide spectrum of organic and inorganic compounds. In the thermophilic microbial community, they can fulfil both degradative and productive functions. Thermophilic prokaryotes probably carried out global reduction of metals on Earth in ancient times, and, at the same time, they are promising candidates for use in modern biotechnological processes. 相似文献
15.
When nitrate was added to anaerobic resting cultures of Escherichia coli, two different profiles of NAD(P)H fluorescence were observed. E. coli is known to reduce nitrate to ammonia via nitrite as an anaerobic respiration mechanism. The profile showing single-stage response corresponded to situations where the nitrite formed from nitrate reduction was immediately converted to ammonia. The other profile showing two-stage response resulted from a much slower reduction of nitrite than nitrate. Nitrite thus accumulated during the first stage and was gradually reduced to ammonia when nitrate was depleted, i.e. in the second stage. An undamped oscillation of NAD(P)H fluorescence was also observed in the cultures showing the two-stage response. The oscillation was always detected during the second stage and seldom during either the first stage or the recovered anaerobic stage (after complete nitrite reduction). It never occurred in the cultures showing the single-stage response. The period of oscillation ranged from 1 to 5min. The possibility of the common glycolytic oscillation being responsible is low, as judged from the current knowledge of the nitrate/nitrite reductases of E. coli and the observations in this study. This is the first report on the occurrence of oscillatory NAD(P)H fluorescence in E. coli. 相似文献
16.
Marko P. Hekkert Dolf J. Gielen Ernst Worrell Wim C. Turkenburg 《Journal of Industrial Ecology》2001,5(1):55-75
The use of packaging materials results in greenhouse gas (GHG) emissions through production and transport of materials and packaging and through end-of-life management. In this article, we investigate the potential reduction of GHGs that are related to packaging. For this purpose, we use the dynamic MATTER-MARKAL model in which the western European energy and materials system is modeled. The results show that GHGs related to packaging can technically be reduced by up to 58% in the period 1995–2030. Current European packaging directives will result in a 10% emission reduction. Cost-effective improved material management 1 that includes lightweighting, reusable packages, material recycling, and related strategies can contribute a 22% GHG emission reduction. An additional 13% reduction becomes cost effective when a GHG emission penalty of 100 euros per metric ton 2 (EUR/ton) is introduced (1 EUR 0.9 USD). Generally speaking, improved material management dominates the gains that can be achieved without a penalty or with low GHG emission penalties (up to 100 EUR/ton CO2 equivalent). By contrast, the reduction of emissions in materials production and waste handling dominate when high GHG penalties are applied (between 100 and 500 EUR/ton CO2 equivalent). Given the significant technical potential and the low costs, more attention should be paid to material efficiency improvement in GHG emission reduction strategies. 相似文献
17.
Katsumi Niki Yumiko Takizawa Hiroaki Kumagai Ryoji Fujiwara Tatsuhiko Yagi Hiroo Inokuchi 《BBA》1981,636(2):136-143
The electrocatalytic activity of cytochrome c3 for the reduction of molecular oxygen was characterized from the studies of the adsorption of cytochrome c3 and the co-adsorption of cytochrome c3 with cytochrome c on the mercury electrode by the a.c. polarographic technique. The adsorption of cytochrome c3 on the mercury electrode is irreversible and is diffusion-controlled. The maximum amount of cytochrome c3 adsorbed was 0.92 · 10?11 mol · cm?2 at ?0.90 V. The amount of cytochrome c3 in the mixed adsorbed layer with cytochrome c was determined from the differential capacitance measurement. It was shown that the fractional coverage of cytochrome c3 can be estimated from its bulk concentration and the diffusion coefficient (1.05 · 10?6 cm2 · s?1). Cytochrome c3 catalyzes the electrochemical reduction of molecular oxygen from the two-electron pathways via hydrogen peroxide to the four-electron pathway at the mercury electrode in neutral phosphate buffer solution. The catalytic activity varies with the bulk concentration of cytochrome c3. The highest catalytic activity for the oxygen reduction (no hydrogen peroxide formation) is attained when one-half of the mercury electrode surface is covered by cytochrome c3. The addition of cytochrome c or bovine serum albumin to the cytochrome c3 solution inhibits the catalytic activity of cytochrome c3. The reversible polarographic behavior of cytochrome c3 through the mixed adsorbed layer of cytochrome c3 and cytochrome c was also investigated. 相似文献
18.
Anatoly A. Fagin 《Inorganica chimica acta》2007,360(9):2923-2928
The reaction of neodymium diiodide NdI2 (1) with acetonitrile is accompanied by C-C coupling and formation of bis(ethylimine)ethylamine/acetonitrile complexes {[(MeCNH)2CMeNH2]NdI(MeCN)5}I2 (2) and {[(MeCNH)2CMeNH2]Nd(MeCN)6}I3 (3). Yields of the products are 9% and 50%, respectively. Probable scheme of the complexes formation is discussed. Treatment of 3 with 2 equiv. of 1 in THF affords NdI3(THF)3, hydrogen and monoiodide complex containing presumably bis(imide)amine ligand, NdI[(MeCN)2CMeNH2]. The X-ray analysis revealed that in the molecule of 2 one I− anion is directly bonded to Nd3+ cation while two other I−anions are not in contact to the metal centre. The molecule of 3 is isostructural to previously obtained Dy and Tm analogues. All three I− anions in it are located away from Nd3+ cation. 相似文献
19.
Non-nitrate-reducing collection bacteria from the genus Pseudomonas were found to be able to use hexavalent chromium as a terminal electron acceptor. The reduction of Cr(VI) was accompanied by an increase in the cell biomass. At Cr(VI) concentrations in the medium lower than 15 mg/l, the non-nitrate-reducing pseudomonads reduced Cr(VI) less efficiently than did denitrifying pseudomonads. In contrast, at Cr(VI) concentrations higher than 30 mg/l, Cr(VI) was reduced more efficiently by the non-nitrate-reducing pseudomonads than by the denitrifying pseudomonads. 相似文献