The Experts below are selected from a list of 2112 Experts worldwide ranked by ideXlab platform
Derek R. Lovley - One of the best experts on this subject based on the ideXlab platform.
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dissimilatory fe iii reduction by the Marine Microorganism desulfuromonas acetoxidans
1993Co-Authors: Eric E. Roden, Derek R. LovleyAbstract:The ability of the Marine Microorganism Desulfuromonas acetoxidans to reduce Fe(III) was investigated because of its close phylogenetic relationship with the freshwater dissimilatory Fe(III) reducer Geobacter metallireducens. Washed cell suspensions of the type strain of D. acetoxidans reduced soluble Fe(III)-citrate and Fe(III) complexed with nitriloacetic acid. The c-type cytochrome(s) of D. acetoxidans was oxidized by Fe(III)-citrate and Mn(IV)-oxalate, as well as by two electron acceptors known to support growth, colloidal sulfur and malate. D. acetoxidans grew in defined anoxic, bicarbonate-buffered medium with acetate as the sole electron donor and poorly crystalline Fe(III) or Mn(IV) as the sole electron acceptor. Magnetite (Fe(3)O(4)) and siderite (FeCO(3)) were the major end products of Fe(III) reduction, whereas rhodochrosite (MnCO(3)) was the end product of Mn(IV) reduction. Ethanol, propanol, pyruvate, and butanol also served as electron donors for Fe(III) reduction. In contrast to D. acetoxidans, G. metallireducens could only grow in freshwater medium and it did not conserve energy to support growth from colloidal S reduction. D. acetoxidans is the first Marine Microorganism shown to conserve energy to support growth by coupling the complete oxidation of organic compounds to the reduction of Fe(III) or Mn(IV). Thus, D. acetoxidans provides a model enzymatic mechanism for Fe(III) or Mn(IV) oxidation of organic compounds in Marine and estuarine sediments. These findings demonstrate that 16S rRNA phylogenetic analyses can suggest previously unrecognized metabolic capabilities of Microorganisms.
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dissimilatory fe iii reduction bytheMarineMicroorganism desulfuromonas acetoxidans
1993Co-Authors: Derek R. LovleyAbstract:mediumwithacetate asthesole electron donorandpoorly crystalline Fe(III) orMn(IV) asthesoleelectron acceptor. Magnetite (Fe304) and siderite (FeCO3) were themajorendproducts ofFe(III) reduction, whereasrhodochrosite (MnCO3) was the endproduct ofMn(IV)reduction. Ethanol, propanol, pyruvate, andbutanol alsoserved aselectron donorsfor Fe(III) reduction. Incontrast toD.acetoxidans, G.metallireducens could only growinfreshwater mediumand itdidnotconserveenergytosupport growth fromcolloidal S reduction. D.acetoxidans isthefirst Marine Microorganism showntoconserveenergytosupport growth bycoupling thecomplete oxidation oforganic compounds tothereduction ofFe(III) orMn(IV). Thus, D.acetoxidans provides amodelenzymatic mechanism forFe(III) or Mn(IV)oxidation oforganic compounds inMarineandestuarine sediments. Thesefindings demonstrate that16SrRNAphylogenetic analyses can suggest previously unrecognized metabolic capabilities of Microorganisms.
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dissimilatory fe iii reduction bytheMarineMicroorganism desulfuromonas acetoxidans
1993Co-Authors: Derek R. LovleyAbstract:mediumwithacetate asthesole electron donorandpoorly crystalline Fe(III) orMn(IV) asthesoleelectron acceptor. Magnetite (Fe304) and siderite (FeCO3) were themajorendproducts ofFe(III) reduction, whereasrhodochrosite (MnCO3) was the endproduct ofMn(IV)reduction. Ethanol, propanol, pyruvate, andbutanol alsoserved aselectron donorsfor Fe(III) reduction. Incontrast toD.acetoxidans, G.metallireducens could only growinfreshwater mediumand itdidnotconserveenergytosupport growth fromcolloidal S reduction. D.acetoxidans isthefirst Marine Microorganism showntoconserveenergytosupport growth bycoupling thecomplete oxidation oforganic compounds tothereduction ofFe(III) orMn(IV). Thus, D.acetoxidans provides amodelenzymatic mechanism forFe(III) or Mn(IV)oxidation oforganic compounds inMarineandestuarine sediments. Thesefindings demonstrate that16SrRNAphylogenetic analyses can suggest previously unrecognized metabolic capabilities of Microorganisms.
Eric E. Roden - One of the best experts on this subject based on the ideXlab platform.
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dissimilatory fe iii reduction by the Marine Microorganism desulfuromonas acetoxidans
1993Co-Authors: Eric E. Roden, Derek R. LovleyAbstract:The ability of the Marine Microorganism Desulfuromonas acetoxidans to reduce Fe(III) was investigated because of its close phylogenetic relationship with the freshwater dissimilatory Fe(III) reducer Geobacter metallireducens. Washed cell suspensions of the type strain of D. acetoxidans reduced soluble Fe(III)-citrate and Fe(III) complexed with nitriloacetic acid. The c-type cytochrome(s) of D. acetoxidans was oxidized by Fe(III)-citrate and Mn(IV)-oxalate, as well as by two electron acceptors known to support growth, colloidal sulfur and malate. D. acetoxidans grew in defined anoxic, bicarbonate-buffered medium with acetate as the sole electron donor and poorly crystalline Fe(III) or Mn(IV) as the sole electron acceptor. Magnetite (Fe(3)O(4)) and siderite (FeCO(3)) were the major end products of Fe(III) reduction, whereas rhodochrosite (MnCO(3)) was the end product of Mn(IV) reduction. Ethanol, propanol, pyruvate, and butanol also served as electron donors for Fe(III) reduction. In contrast to D. acetoxidans, G. metallireducens could only grow in freshwater medium and it did not conserve energy to support growth from colloidal S reduction. D. acetoxidans is the first Marine Microorganism shown to conserve energy to support growth by coupling the complete oxidation of organic compounds to the reduction of Fe(III) or Mn(IV). Thus, D. acetoxidans provides a model enzymatic mechanism for Fe(III) or Mn(IV) oxidation of organic compounds in Marine and estuarine sediments. These findings demonstrate that 16S rRNA phylogenetic analyses can suggest previously unrecognized metabolic capabilities of Microorganisms.
Jinwoo Lee - One of the best experts on this subject based on the ideXlab platform.
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enhanced production of carboxymethylcellulase of a Marine Microorganism bacillus subtilis subsp subtilis a 53 in a pilot scaled bioreactor by a recombinant escherichia coli jm109 a 53 from rice bran
2013Co-Authors: Eunjung Lee, Bohwa Lee, Bokyung Kim, Jinwoo LeeAbstract:A gene encoding the carboxymethylcellulase (CMCase) of a Marine bacterium, Bacillus subtilis subsp. subtilis A-53, was cloned in Escherichia coli JMB109 and the recombinant strain was named as E. coli JMB109/A-53. The optimal conditions of rice bran, ammonium chloride, and initial pH of the medium for cell growth, extracted by Design Expert Software based on response surface methodology, were 100.0 g/l, 7.5 g/l, and 7.0, respectively, whereas those for production of CMCase were 100.0 g/l, 7.5 g/l, and 8.0. The optimal temperatures for cell growth and the production of CMCase by E. coli JM109/A-53 were found to be and 40 and 35 °C, respectively. The optimal agitation speed and aeration rate of a 7 l bioreactor for cell growth were 400 rpm and 1.5 vvm, whereas those for production of CMCase were 400 rpm and 0.5 vvm. The optimal inner pressure for cell growth was 0.06 MPa, which was the same as that for production of CMCase. The production of CMCase by E. coli JM109/A-53 under optimized conditions was 880.2 U/ml, which was 2.9 times higher than that before optimization. In this study, rice bran and ammonium chloride were developed as carbon and nitrogen source for production of CMCase by a recombinant E. coli JM109/A-53 and the productivity of E. coli JM109/A-53 was 5.9 times higher than that of B. subtilis subp. subtilis A-53.
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enhanced production of carboxymethylcellulase by a newly isolated Marine Microorganism bacillus atrophaeus lbh 18 using rice bran a byproduct from the rice processing industry
2012Co-Authors: Yijoon Kim, Wa Cao, Yujeong Lee, Sangun Lee, Jeonghan Jeong, Jinwoo LeeAbstract:A Microorganism producing carboxymethylcellulase (CMCase) was isolated from seawater and identified as Bacillus atrophaeus. This species was designated as B. atrophaeus LBH-18 based on its evolutionary distance and the phylogenetic tree resulting from 16S rDNA sequencing and the neighbor-joining method. The optimal conditions for rice bran (68.1 g/l), peptone (9.1 g/l), and initial pH (7.0) of the medium for cell growth was determined by Design Expert Software based on the response surface method; conditions for production of CMCase were 55.2 g/l, 6.6 g/l, and 7.1, respectively. The optimal temperature for cell growth and the production of CMCase by B. atrophaeus LBH-18 was 30℃. The optimal conditions of agitation speed and aeration rate for cell growth in a 7-l bioreactor were 324 rpm and 0.9 vvm, respectively, whereas those for production of CMCase were 343 rpm and 0.6 vvm, respectively. The optimal inner pressure for cell growth and production of CMCase in a 100-l bioreactor was 0.06 MPa. Maximal production of CMCase under optimal conditions in a 100-l bioreactor was 127.5 U/ml, which was 1.32 times higher than that without an inner pressure. In this study, rice bran was developed as a carbon source for industrial scale production of CMCase by B. atrophaeus LBH-18. Reduced time for the production of CMCase from 7 to 10 days to 3 days by using a bacterial strain with submerged fermentation also resulted in increased productivity of CMCase and a decrease in its production cost.
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characterization of acidic carboxymethylcellulase produced by a Marine Microorganism psychrobacter aquimaris lbh 10
2010Co-Authors: Hyejin Kim, Chunghan Chung, Wa Gao, Youjung Lee, Jinwoo LeeAbstract:A Microorganism hydrolyzing carboxymethylcellulose (CMC) was isolated from seawater, identified as Psychrobacter aquimaris by analysis of 16S rDNA sequences, and named P. aquimari LBH-10. This strain produced an acidic carboxymethylcellulase (CMCase), which hydrolyzed carboxymethylcellulose (CMC), cellobiose, curdlan, filter paper, p-nitrophenyl-β-D-glucopyranoside (pNPG), pullulan, and xylan, but there was no detectable activity on avicel and cellulose. The optimal temperature for CMCase produced by P. aquimari LBH-10 was 50℃ and more than 90% of its original activity was maintained at broad temperatures ranging from 20 to 50℃ after 24 hr. The optimal pH of the CMCase was 3.5, and more than 70% of its original activity was maintained under acidic conditions between pH 2.5 and 7.0 at 50℃ after 24 hr. The optimal pH of CMCase produced by P. aquimaris LBH-10 seems to be lower than those produced by any other bacterial and fungal strain. CoCl₂, EDTA, and PbCl₂ at a concentration of 0.1 M enhanced CMCase-produced P. aquimaris LBH-10, whereas HgCl₂, KCl, MnCl₂, NiCl₂, and SrCl₂ inhibited it.
Ricardo Calado - One of the best experts on this subject based on the ideXlab platform.
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Marine Microorganism invertebrate assemblages perspectives to solve the supply problem in the initial steps of drug discovery
2014Co-Authors: Miguel Costa Leal, Christopher Sheridan, Ronald Osinga, Gisela Dionisio, Rui J M Rocha, Bruna Silva, Rui Rosa, Ricardo CaladoAbstract:The chemical diversity associated with Marine natural products (MNP) is unanimously acknowledged as the “blue gold” in the urgent quest for new drugs. Consequently, a significant increase in the discovery of MNP published in the literature has been observed in the past decades, particularly from Marine invertebrates. However, it remains unclear whether target metabolites originate from the Marine invertebrates themselves or from their microbial symbionts. This issue underlines critical challenges associated with the lack of biomass required to supply the early stages of the drug discovery pipeline. The present review discusses potential solutions for such challenges, with particular emphasis on innovative approaches to culture invertebrate holobionts (Microorganism-invertebrate assemblages) through in toto aquaculture, together with methods for the discovery and initial production of bioactive compounds from these microbial symbionts.
Martin Muhling - One of the best experts on this subject based on the ideXlab platform.
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isolation and initial characterization of a novel type of baeyer villiger monooxygenase activity from a Marine Microorganism
2012Co-Authors: Andrew Willetts, Ian Joint, Jack A Gilbert, W Trimble, Martin MuhlingAbstract:A novel type of Baeyer-Villiger monooxygenase (BVMO) has been found in a Marine strain of Stenotrophomonas maltophila strain PML168 that was isolated from a temperate intertidal zone. The enzyme is able to use NADH as the source of reducing power necessary to accept the atom of diatomic oxygen not incorporated into the oxyfunctionalized substrate. Growth studies have establish that the enzyme is inducible, appears to serve a catabolic role, and is specifically induced by one or more unidentified components of seawater as well as various anthropogenic xenobiotic compounds. A blast search of the primary sequence of the enzyme, recovered from the genomic sequence of the isolate, has placed this atypical BVMO in the context of the several hundred known members of the flavoprotein monooxygenase superfamily. A particular feature of this BVMO lies in its truncated C-terminal domain, which results in a relatively small protein (357 amino acids; 38.4 kDa). In addition, metagenomic screening has been conducted on DNA recovered from an extensive range of Marine environmental samples to gauge the relative abundance and distribution of similar enzymes within the global Marine microbial community. Although low, abundance was detected in samples from many Marine provinces, confirming the potential for biodiscovery in Marine Microorganisms.