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Aeromonas caviae

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Masaaki Iwanaga – One of the best experts on this subject based on the ideXlab platform.

Claudia Toma – One of the best experts on this subject based on the ideXlab platform.

  • Purification and characterization of a novel metalloprotease isolated from Aeromonas caviae.
    FEMS microbiology letters, 2004
    Co-Authors: Noboru Nakasone, Claudia Toma, Tianyan Song, Masaaki Iwanaga
    Abstract:

    A novel protease produced by Aeromonas caviae was purified and characterized. The molecular weight of the protease (AP19) was estimated as 19 kDa on SDS–polyacrylamide gel electrophoresis. The protease activity was not inhibited completely by heating at 100 °C for 15 min. The proteolytic activities were inhibited by metalloprotease inhibitor. The N-terminal amino acid sequence of AP19 was VTASVSFSGRCTN. AP19 did not activate Aeromonas proaerolysin, and did not show fluid accumulation in the rabbit intestinal loop test. A high concentration of the protease showed cytotoxic activity against Vero cells.

  • Purification and characterization of an Aeromonas caviae metalloprotease that is related to the Vibrio cholerae hemagglutinin/protease
    FEMS microbiology letters, 1999
    Co-Authors: Claudia Toma, Yoshio Ichinose, Masaaki Iwanaga
    Abstract:

    A zinc metalloprotease (AP34) from Aeromonas caviae was purified by ammonium sulfate precipitation and subsequent gel filtration through Sephadex G-100 and Sephadex G-50 Superfine. The molecular mass was estimated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis to be 34 kDa. The protease showed maximum activity at pH 7.0 and was stable at 60 degrees C. AP34 was completely inactivated by EDTA and Zincov. The N-terminal amino acid sequence of AP34 showed a high degree of homology with a range of proteases within the family Vibrionaceae, including the hemagglutinin/protease (HA/P) of Vibrio cholerae. Immunologic relatedness of AP34 and HA/P was demonstrated by Western blotting. AP34-like protease was widely distributed among the aeromonad strains.

  • purification and characterization of an Aeromonas caviae metalloprotease that is related to the vibrio cholerae hemagglutinin protease
    Fems Microbiology Letters, 1999
    Co-Authors: Claudia Toma, Yoshio Ichinose, Masaaki Iwanaga
    Abstract:

    A zinc metalloprotease (AP34) from Aeromonas caviae was purified by ammonium sulfate precipitation and subsequent gel filtration through Sephadex G-100 and Sephadex G-50 Superfine. The molecular mass was estimated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis to be 34 kDa. The protease showed maximum activity at pH 7.0 and was stable at 60 degrees C. AP34 was completely inactivated by EDTA and Zincov. The N-terminal amino acid sequence of AP34 showed a high degree of homology with a range of proteases within the family Vibrionaceae, including the hemagglutinin/protease (HA/P) of Vibrio cholerae. Immunologic relatedness of AP34 and HA/P was demonstrated by Western blotting. AP34-like protease was widely distributed among the aeromonad strains.

Claudio C. Vásquez – One of the best experts on this subject based on the ideXlab platform.

  • On the mechanism underlying tellurite reduction by Aeromonas caviae ST dihydrolipoamide dehydrogenase
    Biochimie, 2014
    Co-Authors: Felipe A. Arenas, C.a. Leal, Camilo A. Pinto, Mauricio Arenas-salinas, W.a. Morales, Fabián A. Cornejo, Waldo A. Díaz-vásquez, Claudio C. Vásquez
    Abstract:

    Abstract The dihydrolipoamide dehydrogenase (LpdA) from the tellurite-resistant bacterium Aeromonas caviae ST reduces tellurite to elemental tellurium. To characterize this NADH-dependent activity, the A. caviae lpdA gene was subjected to site-directed mutamutagenesis and genes containing C45A, H322Y and E354K substitutions were individually transformed into Escherichia coli Δlpd. Cells expressing the modified genes exhibited decreased pyruvate dehydrogenase, dihydrolipoamide dehydrogenase and TR activity regarding that observed with the wild type A. caviae lpdA gene. In addition, cells expressing the altered lpdA genes showed increased oxidative stress levels and tellurite sensitivity than those carrying the wild type counterpart. The involvement of Cys residues in LpdA’s TR activity was analyzed using specific inhibitors that interact with catalytic cysteines and/or disulfide bridges such as aurothiomalate, zinc or nickel. TR activity of purified LpdA was drastically affected by these compounds. Since LpdA belongs to the flavoprotein family, the involvement of the FAD/NAD(P)+-binding domain in TR activity was determined. FAD removal from purified LpdA results in loss of TR activity, which was restored with exogenously added FAD. Substitutions in E354, involved in FAD/NADH binding, resulted in low TR activity because of flavin loss. Finally, changing H322 (involved in NAD+/NADH binding) by tyrosine also resulted in altered TR activity.

  • Expression of Aeromonas caviae ST pyruvate dehydrogenase complex components mediate tellurite resistance in Escherichia coli.
    Biochemical and biophysical research communications, 2009
    Co-Authors: Miguel E. Castro, Roberto C Molina, Waldo A Diaz, Gonzalo A. Pradenas, Claudio C. Vásquez
    Abstract:

    Potassium tellurite (K{sub 2}TeO{sub 3}) is harmful to most organisms and specific mechanisms explaining its toxicity are not well known to date. We previously reported that the lpdA gene product of the tellurite-resistant environmental isolate Aeromonas caviae ST is involved in the reduction of tellurite to elemental tellurium. In this work, we show that expression of A. caviae ST aceE, aceF, and lpdA genes, encoding pyruvate dehydrogenase, dihydrolipoamide transacetylase, and dihydrolipoamide dehydrogenase, respectively, results in tellurite resistance and decreased levels of tellurite-induced superoxide in Escherichia coli. In addition to oxidative damage resulting from tellurite exposure, a metabolic disorder would be simultaneously established in which the pyruvate dehydrogenase complex would represent an intracellular tellurite target. These results allow us to widen our vision regarding the molecular mechanisms involved in bacterial tellurite resistance by correlating tellurite toxicity and key enzymes of aerobic metametabolism.

  • the dihydrolipoamide dehydrogenase of Aeromonas caviae st exhibits nadh dependent tellurite reductase activity
    Biochemical and Biophysical Research Communications, 2008
    Co-Authors: Miguel E. Castro, Roberto C Molina, Waldo A Diaz, Sergio Pichuantes, Claudio C. Vásquez
    Abstract:

    Abstract Potassium tellurite (K2TeO3) is extremely toxic for most forms of life and only a limited number of organisms are naturally resistant to the toxic effects of this compound. Crude extracts prepared from the environmental isolate Aeromonas caviae ST catalize the in vitro reduction of TeO 3 2 – in a NADH-dependent reaction. Upon fractionation by ionic exchange column chrochromatography three major polypeptides identified as the E1, E2, and E3 components of the pyruvate dehydrogenase (PDH) complex were identified in fractions exhibiting tellurite-reducing activity. Tellurite reductase and pyruvate dehydrogenase activities co-eluted from a Sephadex gel filtfiltration column. To determine which component(s) of the PDH complex has tellurite reductase activity, the A. caviae ST structural genes encoding for E1 (aceE), E2 (aceF), and E3 (lpdA) were independently cloned and expressed in Escherichia coli and their gene products purified. Results indicated that tellurite reductase activity lies almost exclusively in the E3 component, dihydrolipoamide dehydrogenase. The E3 component of the PDH complex from E. coli, Zymomonas mobilis, Streptococcus pneupneumoniae, and Geobacillus stearothermophilus also showed NADH-dependent tellurite reductase in vitro suggesting that this enzymatic activity is widely distributed among microorganisms.

Kostas A. Matis – One of the best experts on this subject based on the ideXlab platform.

  • Cadmium(II) Biosorption by Aeromonas caviae: Kinetic Modeling
    Separation Science and Technology, 2005
    Co-Authors: M. X. Loukidou, Thodoris D. Karapantsios, Anastasios I. Zouboulis, Kostas A. Matis
    Abstract:

    Abstract Biosorption of cadmium from aqueous solutions on Aeromonas caviae particles was investigated in a well‐stirred batch reactor. Equilibrium and kinetic experiments were performed at various initial bulk concentrations, biomass loads, temperatures, and ionic background. Equilibrium data were well described by typical Langmuir and Freundlich adsorption isotherms. Furthermore, a detailed analysis was conducted to test several chemical reaction kinetic models in order to identify a suitable kinetic equation, assuming that biosorption is chemical sorption controlled. Predictions based on the so‐called pseudo second order rate expression were found in satisfactory accordance with experimental data.

  • Equilibrium and kinetic modeling of chromium(VI) biosorption by Aeromonas caviae
    Colloids and Surfaces A: Physicochemical and Engineering Aspects, 2004
    Co-Authors: M. X. Loukidou, Thodoris D. Karapantsios, Anastasios I. Zouboulis, Kostas A. Matis
    Abstract:

    Biosorption of hexavalent chromium, from aqueous solutions, on Aeromonas caviae particles was investigated in a well-stirred batch reactor. Equilibrium and kinetic experiments were performed at various initial bulk concentrations, biomass loads, temperatures and ionic background. Equilibrium data were well described by typical Langmuir and Freundlich adsorption isotherms. Furthermore, a detailed analysis has been conducted testing several chemical reaction kinetic models in order to identify a suitable kinetic equation, assuming that biosorption is chemical sorption controlled. Predictions based on the so-called pseudo second order rate expression were found in satisfactory accordance with experimental data.

  • Diffusion kinetic study of cadmium(II) biosorption by Aeromonas caviae
    Journal of Chemical Technology & Biotechnology, 2004
    Co-Authors: M. X. Loukidou, Thodoris D. Karapantsios, Anastasios I. Zouboulis, Kostas A. Matis
    Abstract:

    The removal of cadmium from aqueous solution by sorption on Aeromonas caviae particles was investigated in a well-stirred batch reactor. Equilibrium and kinetic experiments were performed at various initial bulk concentrations, biomass loads and temperatures. Biosorption equilibrium was established in about 1 h and biosorption was well described by the Langmuir and Freundlich biosorption isotherms. The maximum biosorption capacity was found as 155.32 mg Cd(II) g−1 at 20 °C. The obtained sorption capacity is appreciably high for most experimental conditions; so A caviae may be considered as a suitable biosorbent for the removal of cadmium. Moreover, the sorption rate of cadmium onto A caviae particles was particularly sensitive to initial bulk concentration and solid load. A detailed analysis was conducted, examining several diffusion (external and intraparticle) kinetic models in order to identify a suitable rate expression. The results are discussed and indicate that biosorption of cadmium is a complex process that is described more correctly by more than one model. Copyright © 2004 Society of Chemical Industry

M. John Albert – One of the best experts on this subject based on the ideXlab platform.