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Microbial oxidation and reduction of manganese: Consequences in groundwater and applications 总被引:3,自引:0,他引:3
Anne-Monique Gounot 《FEMS microbiology reviews》1994,14(4):339-349
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Siderophores, biogenic chelating agents that facilitate Fe(III) uptake through the formation of strong complexes, also form
strong complexes with Mn(III) and exhibit high reactivity with Mn (hydr)oxides, suggesting a pathway by which Mn may disrupt
Fe uptake. In this review, we evaluate the major biogeochemical mechanisms by which Fe and Mn may interact through reactions
with microbial siderophores: competition for a limited pool of siderophores, sorption of siderophores and metal–siderophore
complexes to mineral surfaces, and competitive metal-siderophore complex formation through parallel mineral dissolution pathways.
This rich interweaving of chemical processes gives rise to an intricate tapestry of interactions, particularly in respect
to the biogeochemical cycling of Fe and Mn in marine ecosystems. 相似文献
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The microbial ecology of anaerobic carbon oxidation processes was investigated in Black Sea shelf sediments from mid-shelf with well-oxygenated bottom water to the oxic-anoxic chemocline at the shelf-break. At all stations, organic carbon (C(org)) oxidation rates were rapidly attenuated with depth in anoxically incubated sediment. Dissimilatory Mn reduction was the most important terminal electron-accepting process in the active surface layer to a depth of approximately 1 cm, while SO(4)(2-) reduction accounted for the entire C(org) oxidation below. Manganese reduction was supported by moderately high Mn oxide concentrations. A contribution from microbial Fe reduction could not be discerned, and the process was not stimulated by addition of ferrihydrite. Manganese reduction resulted in carbonate precipitation, which complicated the quantification of C(org) oxidation rates. The relative contribution of Mn reduction to C(org) oxidation in the anaerobic incubations was 25 to 73% at the stations with oxic bottom water. In situ, where Mn reduction must compete with oxygen respiration, the contribution of the process will vary in response to fluctuations in bottom water oxygen concentrations. Total bacterial numbers as well as the detection frequency of bacteria with fluorescent in situ hybridization scaled to the mineralization rates. Most-probable-number enumerations yielded up to 10(5) cells of acetate-oxidizing Mn-reducing bacteria (MnRB) cm(-3), while counts of Fe reducers were <10(2) cm(-3). At two stations, organisms affiliated with Arcobacter were the only types identified from 16S rRNA clone libraries from the highest positive MPN dilutions for MnRB. At the third station, a clone type affiliated with Pelobacter was also observed. Our results delineate a niche for dissimilatory Mn-reducing bacteria in sediments with Mn oxide concentrations greater than approximately 10 micromol cm(-3) and indicate that bacteria that are specialized in Mn reduction, rather than known Mn and Fe reducers, are important in this niche. 相似文献
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Microbial carbon limitation: The need for integrating microorganisms into our understanding of ecosystem carbon cycling 总被引:2,自引:0,他引:2
Jennifer L. Soong Lucia Fuchslueger Sara Maraon‐Jimenez Margaret S. Torn Ivan A. Janssens Josep Penuelas Andreas Richter 《Global Change Biology》2020,26(4):1953-1961
Numerous studies have demonstrated that fertilization with nutrients such as nitrogen, phosphorus, and potassium increases plant productivity in both natural and managed ecosystems, demonstrating that primary productivity is nutrient limited in most terrestrial ecosystems. In contrast, it has been demonstrated that heterotrophic microbial communities in soil are primarily limited by organic carbon or energy. While this concept of contrasting limitations, that is, microbial carbon and plant nutrient limitation, is based on strong evidence that we review in this paper, it is often ignored in discussions of ecosystem response to global environment changes. The plant‐centric perspective has equated plant nutrient limitations with those of whole ecosystems, thereby ignoring the important role of the heterotrophs responsible for soil decomposition in driving ecosystem carbon storage. To truly integrate carbon and nutrient cycles in ecosystem science, we must account for the fact that while plant productivity may be nutrient limited, the secondary productivity by heterotrophic communities is inherently carbon limited. Ecosystem carbon cycling integrates the independent physiological responses of its individual components, as well as tightly coupled exchanges between autotrophs and heterotrophs. To the extent that the interacting autotrophic and heterotrophic processes are controlled by organisms that are limited by nutrient versus carbon accessibility, respectively, we propose that ecosystems by definition cannot be ‘limited’ by nutrients or carbon alone. Here, we outline how models aimed at predicting non‐steady state ecosystem responses over time can benefit from dissecting ecosystems into the organismal components and their inherent limitations to better represent plant–microbe interactions in coupled carbon and nutrient models. 相似文献
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Jan S⊘rensen 《Geomicrobiology journal》2013,30(3-4):401-421
Abstract In coastal marine sediments, the interactions between NO3 ? reduction and transformations of Fe and S compounds often occur in a strong gradient of electron activity ("redoxcline"). Denitrification activity is observed throughout the NC3 ?‐containing surface zone, although the reduction step from N2O to N2 can be inhibited by H2S in the “redoxcline.”; Survival of denitrifiers is generally poor in NO3 ?‐free, reduced sediment; such populations are likely to employ Fe3+ reduction in their energy metabolism. At depth, the sediments often contain a larger capacity for “nitrate ammonification”; (dissimilatory NO3 ? reduction to NH4 +) than for denitrification. The “nitrate ammonification”; is found commonly among fermenting bacteria, although SO4 2? reducers may also be involved. In situ activities observed in whole sediment cores indicate that “nitrate ammonification”; may account for as much as one‐third of the carbon oxidation in organic‐rich sediments. The control of partitioning between denitrification and “nitrate ammonification”; at low NO3 ? concentrations is poorly investigated, but the larger metabolic capacity of fermenting and S O4 2?‐reducing baceria in relatively reduced sediment could be important. In addition to bacterial reduction, chemical NO3 ? reduction is possible where significant amounts of Fe2+ (or H2S) accumulate in the “redoxcline.”; 相似文献
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Nadia Szeinbaum Hui Lin Jay A. Brandes Martial Taillefert Jennifer B. Glass Thomas J. DiChristina 《Environmental microbiology》2017,19(9):3475-3486
Soluble manganese in the intermediate +III oxidation state (Mn3+) is a newly identified oxidant in anoxic environments, whereas acetate is a naturally abundant substrate that fuels microbial activity. Microbial populations coupling anaerobic acetate oxidation to Mn3+ reduction, however, have yet to be identified. We isolated a Shewanella strain capable of oxidizing acetate anaerobically with Mn3+ as the electron acceptor, and confirmed this phenotype in other strains. This metabolic connection between acetate and soluble Mn3+ represents a new biogeochemical link between carbon and manganese cycles. Genomic analyses uncovered four distinct genes that allow for pathway variations in the complete dehydrogenase‐driven TCA cycle that could support anaerobic acetate oxidation coupled to metal reduction in Shewanella and other Gammaproteobacteria. An oxygen‐tolerant TCA cycle supporting anaerobic manganese reduction is thus a new connection in the manganese‐driven carbon cycle, and a new variable for models that use manganese as a proxy to infer oxygenation events on early Earth. 相似文献
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One hundred and five strains isolated from aquifer sediments andEscherichia coli ML30S were tested for their ability to reduce manganese oxides. Eighty-two strains, includingE. coli, reduced manganese. In most cases the bacterial activity decreased the pH and Eh below 6.75 and 350 mV, respectively, enhancing
a spontaneous and nonspecific reduction of manganese. However, for 12 strains the reduction was specifically catalyzed by
bacteria; the high pH and Eh values would not permit a spontaneous reduction of manganese. Some of the most active strains
were identified as genera common in soils and waters, i.e.,Pseudomonas, Bacillus, Corynebacterium, andAcinetobacter. Two strains were studied in detail. One of the strains, identified asPseudomonas fluorescens, required contact between the cells and the manganese oxides for reduction to occur. The reduction was inhibited by 15 mM
of sodium azide. The other strain, identified asAcinetobacter johnsonii, catalyzed manganese reduction by an inductive and dialyzable substance which was excreted by the bacteria. The mechanism
involved has not been previously demonstrated. 相似文献
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Microbial perchlorate reduction: rocket-fueled metabolism. 总被引:1,自引:0,他引:1
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Mary E. Lidstrom 《Antonie van Leeuwenhoek》1989,55(1):7-14
Summary By using molecular probe techniques in combination with activity and expression measurements, it is possible to estimate bacterial
populations in nature. This information can be expooited to study a number of important environmental problems. For instance,
it will be possible to study ecosystem perturbation and microbial competition, by altering an ecosystem or a laboratory model
of an ecosystem, and assessing corresponding changes in key activities and populations. In addition, regulation of activities
in the laboratory can be compared to the response of activities and populations in situ, to develop an understanding of the
key parameters that control these processes in nature. These types of approaches are important steps for determining the role
of microorganisms in geochemical cycling, in both specific habitats and on a global basis. 相似文献
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Microbial community diversity associated with carbon and nitrogen cycling in permeable shelf sediments 总被引:4,自引:0,他引:4
Though a large fraction of primary production and organic matter cycling in the oceans occurs on continental shelves dominated by sandy deposits, the microbial communities associated with permeable shelf sediments remain poorly characterized. Therefore, in this study, we provide the first detailed characterization of microbial diversity in marine sands of the South Atlantic Bight through parallel analyses of small-subunit (SSU) rRNA gene (Bacteria), nosZ (denitrifying bacteria), and amoA (ammonia-oxidizing bacteria) sequences. Communities were analyzed by parallel DNA extractions and clone library construction from both sediment core material and manipulated sediment within column experiments designed for geochemical rate determinations. Rapid organic-matter degradation and coupled nitrification-denitrification were observed in column experiments at flow rates resembling in situ conditions over a range of oxygen concentrations. Numerous SSU rRNA phylotypes were affiliated with the phyla Proteobacteria (classes Alpha-, Delta-, and Gammaproteobacteria), Planctomycetes, Cyanobacteria, Chloroflexi, and Bacteroidetes. Detectable sequence diversity of nosZ and SSU rRNA genes increased in stratified redox-stabilized columns compared to in situ sediments, with the Alphaproteobacteria comprising the most frequently detected group. Alternatively, nitrifier communities showed a relatively low and stable diversity that did not covary with the other gene targets. Our results elucidate predominant phylotypes that are likely to catalyze carbon and nitrogen cycling in marine sands. Although overall diversity increased in response to redox stabilization and stratification in column experiments, the major phylotypes remained the same in all of our libraries, indicating that the columns sufficiently mimic in situ conditions. 相似文献
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陆地碳循环研究中的模型方法 总被引:20,自引:3,他引:20
陆地碳循环是全球变化研究中的重要内容,碳循环模型已成为研究陆地碳循环的必要方法.其中气候变化、大气CO2浓度上升以及人类活动引起的土地利用和土地覆盖变化导致陆地生态系统在结构、功能、组成和分布等方面的变化及其反馈关系对陆地碳循环的影响是模型模拟的关键问题.生物地理模型和生物地球化学模型是碳循环模型的两大类型,建模方法、模型性质、特点和应用范围各异.碳循环模型的发展方向是综合两类模型的特点,建立全球动态碳循环模型. 相似文献
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Goswami A Mirfakhrae KD Totleben MJ Swaminathan S Patel RN 《Journal of industrial microbiology & biotechnology》2001,26(5):259-262
Microbial reduction of α-chloroketone to α-chlorohydrin was studied as one of the approaches for construction of the chiral
center of the corresponding epoxide. About 100 microorganisms covering many species of Candida, Pichia, Hansenula, Geotrichum, Rhodococcus and Aureobasidium were screened to reduce the α-chloroketone stereospecifically. Many strains provided the R-α-chlorohydrin with 100% enantiomeric excess (ee), e.g., Candida sonorensis SC 16117, Geotrichum candidum SC 5469, Rhodotorula glutinis SC 16293, Sphingomonas paucimobilis SC 16113, Pichia silvicola SC 16159 and Rhodococcus equi SC 15835. Few microorganisms showed preferential formation of S-α-chlorohydrin after reduction. Among them, Pichia pinus SC 13864 and two Pichia methanolica strains SC 16116 and SC 13860 were the best, providing the S-α-chlorohydrin with ee of 88%, 79% and 78%, respectively. The enantiospecificity of the reduction by these Pichia species can be modified by changing the pH or prior heat treatment of the cells and S-α-chlorohydrin with ≥95% ee was obtained by appropriate modification of reaction conditions. Journal of Industrial Microbiology & Biotechnology (2001) 26, 259–262.
Received 23 June 2000/ Accepted in revised form 06 November 2000 相似文献
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A Goswami K D Mirfakhrae M J Totleben S Swaminathan R N Patel 《Journal of industrial microbiology & biotechnology》2002,28(6):349
Journal of Industrial Microbiology &; Biotechnology (2001) 26, 259-262 DOI: 10.1038/sj/jim/7000080 相似文献
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M Papp 《Acta physiologica Hungarica》1992,80(1-4):399-406
A brief report is given on the possible role of oxygen-derived free radicals and cholecystokinin in the pathogenesis of experimentally induced acute pancreatitis. Furthermore, use of scavengers (superoxide dismutase, catalase), CCK-receptor antagonists and somatostatin are discussed in the therapy of acute pancreatitis induced in animal models. It is suggested that both the term of direct pancreatic cytoprotection of the above-mentioned agents and the validity of the animal models used for induction of acute pancreatitis have to be reconsidered. 相似文献