<?xml version="1.0" encoding="UTF-8"?><xml><records><record><source-app name="Biblio" version="7.x">Drupal-Biblio</source-app><ref-type>17</ref-type><contributors><authors><author><style face="normal" font="default" size="100%">Ver Eecke, Helene C</style></author><author><style face="normal" font="default" size="100%">Butterfield, David A</style></author><author><style face="normal" font="default" size="100%">Huber, Julie A</style></author><author><style face="normal" font="default" size="100%">Lilley, Marvin D</style></author><author><style face="normal" font="default" size="100%">Olson, Eric J</style></author><author><style face="normal" font="default" size="100%">Roe, Kevin K</style></author><author><style face="normal" font="default" size="100%">Evans, Leigh J</style></author><author><style face="normal" font="default" size="100%">Merkel, Alexandr Y</style></author><author><style face="normal" font="default" size="100%">Cantin, Holly V</style></author><author><style face="normal" font="default" size="100%">Holden, James F</style></author></authors></contributors><titles><title><style face="normal" font="default" size="100%">Hydrogen-limited growth of hyperthermophilic methanogens at deep-sea hydrothermal vents.</style></title><secondary-title><style face="normal" font="default" size="100%">Proc Natl Acad Sci U S A</style></secondary-title><alt-title><style face="normal" font="default" size="100%">Proc. Natl. Acad. Sci. U.S.A.</style></alt-title></titles><keywords><keyword><style  face="normal" font="default" size="100%">Archaea</style></keyword><keyword><style  face="normal" font="default" size="100%">Biodiversity</style></keyword><keyword><style  face="normal" font="default" size="100%">Coculture Techniques</style></keyword><keyword><style  face="normal" font="default" size="100%">DNA, Ribosomal</style></keyword><keyword><style  face="normal" font="default" size="100%">Ecosystem</style></keyword><keyword><style  face="normal" font="default" size="100%">Gases</style></keyword><keyword><style  face="normal" font="default" size="100%">Geography</style></keyword><keyword><style  face="normal" font="default" size="100%">Hydrogen</style></keyword><keyword><style  face="normal" font="default" size="100%">Hydrothermal Vents</style></keyword><keyword><style  face="normal" font="default" size="100%">Kinetics</style></keyword><keyword><style  face="normal" font="default" size="100%">Methane</style></keyword><keyword><style  face="normal" font="default" size="100%">Molecular Sequence Data</style></keyword><keyword><style  face="normal" font="default" size="100%">Temperature</style></keyword><keyword><style  face="normal" font="default" size="100%">Time Factors</style></keyword><keyword><style  face="normal" font="default" size="100%">Water Microbiology</style></keyword></keywords><dates><year><style  face="normal" font="default" size="100%">2012</style></year><pub-dates><date><style  face="normal" font="default" size="100%">2012 Aug 21</style></date></pub-dates></dates><volume><style face="normal" font="default" size="100%">109</style></volume><pages><style face="normal" font="default" size="100%">13674-9</style></pages><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">&lt;p&gt;Microbial productivity at hydrothermal vents is among the highest found anywhere in the deep ocean, but constraints on microbial growth and metabolism at vents are lacking. We used a combination of cultivation, molecular, and geochemical tools to verify pure culture H(2) threshold measurements for hyperthermophilic methanogenesis in low-temperature hydrothermal fluids from Axial Volcano and Endeavour Segment in the northeastern Pacific Ocean. Two Methanocaldococcus strains from Axial and Methanocaldococcus jannaschii showed similar Monod growth kinetics when grown in a bioreactor at varying H(2) concentrations. Their H(2) half-saturation value was 66 μM, and growth ceased below 17-23 μM H(2), 10-fold lower than previously predicted. By comparison, measured H(2) and CH(4) concentrations in fluids suggest that there was generally sufficient H(2) for Methanocaldococcus growth at Axial but not at Endeavour. Fluids from one vent at Axial (Marker 113) had anomalously high CH(4) concentrations and contained various thermal classes of methanogens based on cultivation and mcrA/mrtA analyses. At Endeavour, methanogens were largely undetectable in fluid samples based on cultivation and molecular screens, although abundances of hyperthermophilic heterotrophs were relatively high. Where present, Methanocaldococcus genes were the predominant mcrA/mrtA sequences recovered and comprised ∼0.2-6% of the total archaeal community. Field and coculture data suggest that H(2) limitation may be partly ameliorated by H(2) syntrophy with hyperthermophilic heterotrophs. These data support our estimated H(2) threshold for hyperthermophilic methanogenesis at vents and highlight the need for coupled laboratory and field measurements to constrain microbial distribution and biogeochemical impacts in the deep sea.&lt;/p&gt;</style></abstract><issue><style face="normal" font="default" size="100%">34</style></issue><custom1><style face="normal" font="default" size="100%">http://www.ncbi.nlm.nih.gov/pubmed/22869718?dopt=Abstract</style></custom1></record><record><source-app name="Biblio" version="7.x">Drupal-Biblio</source-app><ref-type>17</ref-type><contributors><authors><author><style face="normal" font="default" size="100%">Qian, Xinlei</style></author><author><style face="normal" font="default" size="100%">Mester, Tünde</style></author><author><style face="normal" font="default" size="100%">Morgado, Leonor</style></author><author><style face="normal" font="default" size="100%">Arakawa, Tsutomu</style></author><author><style face="normal" font="default" size="100%">Sharma, Manju L</style></author><author><style face="normal" font="default" size="100%">Inoue, Kengo</style></author><author><style face="normal" font="default" size="100%">Joseph, Crisjoe</style></author><author><style face="normal" font="default" size="100%">Salgueiro, Carlos A</style></author><author><style face="normal" font="default" size="100%">Maroney, Michael J</style></author><author><style face="normal" font="default" size="100%">Lovley, Derek R</style></author></authors></contributors><titles><title><style face="normal" font="default" size="100%">Biochemical characterization of purified OmcS, a c-type cytochrome required for insoluble Fe(III) reduction in Geobacter sulfurreducens.</style></title><secondary-title><style face="normal" font="default" size="100%">Biochim Biophys Acta</style></secondary-title><alt-title><style face="normal" font="default" size="100%">Biochim. Biophys. Acta</style></alt-title></titles><keywords><keyword><style  face="normal" font="default" size="100%">Circular Dichroism</style></keyword><keyword><style  face="normal" font="default" size="100%">Cytochrome c Group</style></keyword><keyword><style  face="normal" font="default" size="100%">Geobacter</style></keyword><keyword><style  face="normal" font="default" size="100%">Heme</style></keyword><keyword><style  face="normal" font="default" size="100%">Iron</style></keyword><keyword><style  face="normal" font="default" size="100%">Kinetics</style></keyword><keyword><style  face="normal" font="default" size="100%">Molecular Weight</style></keyword><keyword><style  face="normal" font="default" size="100%">Oxidation-Reduction</style></keyword><keyword><style  face="normal" font="default" size="100%">Solubility</style></keyword></keywords><dates><year><style  face="normal" font="default" size="100%">2011</style></year><pub-dates><date><style  face="normal" font="default" size="100%">2011 Apr</style></date></pub-dates></dates><volume><style face="normal" font="default" size="100%">1807</style></volume><pages><style face="normal" font="default" size="100%">404-12</style></pages><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">Previous studies with Geobacter sulfurreducens have demonstrated that OmcS, an abundant c-type cytochrome that is only loosely bound to the outer surface, plays an important role in electron transfer to Fe(III) oxides as well as other extracellular electron acceptors. In order to further investigate the function of OmcS, it was purified from a strain that overproduces the protein. Purified OmcS had a molecular mass of 47015 Da, and six low-spin bis-histidinyl hexacoordinated heme groups. Its midpoint redox potential was -212 mV. A thermal stability analysis showed that the cooperative melting of purified OmcS occurs in the range of 65-82 °C. Far UV circular dichroism spectroscopy indicated that the secondary structure of purified OmcS consists of about 10% α-helix and abundant disordered structures. Dithionite-reduced OmcS was able to transfer electrons to a variety of substrates of environmental importance including insoluble Fe(III) oxide, Mn(IV) oxide and humic substances. Stopped flow analysis revealed that the reaction rate of OmcS oxidation has a hyperbolic dependence on the concentration of the studied substrates. A ten-fold faster reaction rate with anthraquinone-2,6-disulfonate (AQDS) (25.2 s⁻¹) was observed as compared to that with Fe(III) citrate (2.9 s⁻¹). The results, coupled with previous localization and gene deletion studies, suggest that OmcS is well-suited to play an important role in extracellular electron transfer.</style></abstract><issue><style face="normal" font="default" size="100%">4</style></issue><custom1><style face="normal" font="default" size="100%">http://www.ncbi.nlm.nih.gov/pubmed/21236241?dopt=Abstract</style></custom1></record><record><source-app name="Biblio" version="7.x">Drupal-Biblio</source-app><ref-type>17</ref-type><contributors><authors><author><style face="normal" font="default" size="100%">Zhao, Jiao</style></author><author><style face="normal" font="default" size="100%">Fang, Yilin</style></author><author><style face="normal" font="default" size="100%">Scheibe, Timothy D</style></author><author><style face="normal" font="default" size="100%">Lovley, Derek R</style></author><author><style face="normal" font="default" size="100%">Mahadevan, R</style></author></authors></contributors><titles><title><style face="normal" font="default" size="100%">Modeling and sensitivity analysis of electron capacitance for Geobacter in sedimentary environments.</style></title><secondary-title><style face="normal" font="default" size="100%">J Contam Hydrol</style></secondary-title><alt-title><style face="normal" font="default" size="100%">J. Contam. Hydrol.</style></alt-title></titles><keywords><keyword><style  face="normal" font="default" size="100%">Biodegradation, Environmental</style></keyword><keyword><style  face="normal" font="default" size="100%">Electric Capacitance</style></keyword><keyword><style  face="normal" font="default" size="100%">Geobacter</style></keyword><keyword><style  face="normal" font="default" size="100%">Kinetics</style></keyword><keyword><style  face="normal" font="default" size="100%">Models, Biological</style></keyword><keyword><style  face="normal" font="default" size="100%">Uranium</style></keyword></keywords><dates><year><style  face="normal" font="default" size="100%">2010</style></year><pub-dates><date><style  face="normal" font="default" size="100%">2010 Mar 1</style></date></pub-dates></dates><volume><style face="normal" font="default" size="100%">112</style></volume><pages><style face="normal" font="default" size="100%">30-44</style></pages><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">In situ stimulation of the metabolic activity of Geobacter species through acetate amendment has been shown to be a promising bioremediation strategy to reduce and immobilize hexavalent uranium [U(VI)] as insoluble U(IV). Although Geobacter species are reducing U(VI), they primarily grow via Fe(III) reduction. Unfortunately, the biogeochemistry and the physiology of simultaneous reduction of multiple metals are still poorly understood. A detailed model is therefore required to better understand the pathways leading to U(VI) and Fe(III) reduction by Geobacter species. Based on recent experimental evidence of temporary electron capacitors in Geobacter we propose a novel kinetic model that physically distinguishes planktonic cells into electron-loaded and -unloaded states. Incorporation of an electron load-unload cycle into the model provides insight into U(VI) reduction efficiency, and elucidates the relationship between U(VI)- and Fe(III)-reducing activity and further explains the correlation of high U(VI) removal with high fractions of planktonic cells in subsurface environments. Global sensitivity analysis was used to determine the level of importance of geochemical and microbial processes controlling Geobacter growth and U(VI) reduction, suggesting that the electron load-unload cycle and the resulting repartition of the microbes between aqueous and attached phases are critical for U(VI) reduction. As compared with conventional Monod modeling approaches without inclusion of the electron capacitance, the new model attempts to incorporate a novel cellular mechanism that has a significant impact on the outcome of in situ bioremediation.</style></abstract><issue><style face="normal" font="default" size="100%">1-4</style></issue><custom1><style face="normal" font="default" size="100%">http://www.ncbi.nlm.nih.gov/pubmed/19892431?dopt=Abstract</style></custom1></record><record><source-app name="Biblio" version="7.x">Drupal-Biblio</source-app><ref-type>17</ref-type><contributors><authors><author><style face="normal" font="default" size="100%">Handa, Naofumi</style></author><author><style face="normal" font="default" size="100%">Amitani, Ichiro</style></author><author><style face="normal" font="default" size="100%">Gumlaw, Nathan</style></author><author><style face="normal" font="default" size="100%">Sandler, Steven J</style></author><author><style face="normal" font="default" size="100%">Kowalczykowski, Stephen C</style></author></authors></contributors><titles><title><style face="normal" font="default" size="100%">Single molecule analysis of a red fluorescent RecA protein reveals a defect in nucleoprotein filament nucleation that relates to its reduced biological functions.</style></title><secondary-title><style face="normal" font="default" size="100%">J Biol Chem</style></secondary-title><alt-title><style face="normal" font="default" size="100%">J. Biol. Chem.</style></alt-title></titles><keywords><keyword><style  face="normal" font="default" size="100%">Cell Nucleus</style></keyword><keyword><style  face="normal" font="default" size="100%">DNA</style></keyword><keyword><style  face="normal" font="default" size="100%">DNA, Single-Stranded</style></keyword><keyword><style  face="normal" font="default" size="100%">Escherichia coli</style></keyword><keyword><style  face="normal" font="default" size="100%">Hydrogen-Ion Concentration</style></keyword><keyword><style  face="normal" font="default" size="100%">Kinetics</style></keyword><keyword><style  face="normal" font="default" size="100%">Luminescent Proteins</style></keyword><keyword><style  face="normal" font="default" size="100%">Nucleoproteins</style></keyword><keyword><style  face="normal" font="default" size="100%">Plasmids</style></keyword><keyword><style  face="normal" font="default" size="100%">Protein Binding</style></keyword><keyword><style  face="normal" font="default" size="100%">Rec A Recombinases</style></keyword><keyword><style  face="normal" font="default" size="100%">Recombination, Genetic</style></keyword><keyword><style  face="normal" font="default" size="100%">Sensitivity and Specificity</style></keyword><keyword><style  face="normal" font="default" size="100%">Ultraviolet Rays</style></keyword></keywords><dates><year><style  face="normal" font="default" size="100%">2009</style></year><pub-dates><date><style  face="normal" font="default" size="100%">2009 Jul 10</style></date></pub-dates></dates><volume><style face="normal" font="default" size="100%">284</style></volume><pages><style face="normal" font="default" size="100%">18664-73</style></pages><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">Fluorescent fusion proteins are exceedingly useful for monitoring protein localization in situ or visualizing protein behavior at the single molecule level. Unfortunately, some proteins are rendered inactive by the fusion. To circumvent this problem, we fused a hyperactive RecA protein (RecA803 protein) to monomeric red fluorescent protein (mRFP1) to produce a functional protein (RecA-RFP) that is suitable for in vivo and in vitro analysis. In vivo, the RecA-RFP partially restores UV resistance, conjugational recombination, and SOS induction to recA(-) cells. In vitro, the purified RecA-RFP protein forms a nucleoprotein filament whose k(cat) for single-stranded DNA-dependent ATPase activity is reduced approximately 3-fold relative to wild-type protein, and which is largely inhibited by single-stranded DNA-binding protein. However, RecA protein is also a dATPase; dATP supports RecA-RFP nucleoprotein filament formation in the presence of single-stranded DNA-binding protein. Furthermore, as for the wild-type protein, the activities of RecA-RFP are further enhanced by shifting the pH to 6.2. As a consequence, RecA-RFP is proficient for DNA strand exchange with dATP or at lower pH. Finally, using single molecule visualization, RecA-RFP was seen to assemble into a continuous filament on duplex DNA, and to extend the DNA approximately 1.7-fold. Consistent with its attenuated activities, RecA-RFP nucleates onto double-stranded DNA approximately 3-fold more slowly than the wild-type protein, but still requires approximately 3 monomers to form the rate-limited nucleus needed for filament assembly. Thus, RecA-RFP reveals that its attenuated biological functions correlate with a reduced frequency of nucleoprotein filament nucleation at the single molecule level.</style></abstract><issue><style face="normal" font="default" size="100%">28</style></issue><custom1><style face="normal" font="default" size="100%">http://www.ncbi.nlm.nih.gov/pubmed/19419960?dopt=Abstract</style></custom1></record><record><source-app name="Biblio" version="7.x">Drupal-Biblio</source-app><ref-type>17</ref-type><contributors><authors><author><style face="normal" font="default" size="100%">Yennaco, Lynda J</style></author><author><style face="normal" font="default" size="100%">Hu, Yajing</style></author><author><style face="normal" font="default" size="100%">Holden, James F</style></author></authors></contributors><titles><title><style face="normal" font="default" size="100%">Characterization of malate dehydrogenase from the hyperthermophilic archaeon Pyrobaculum islandicum.</style></title><secondary-title><style face="normal" font="default" size="100%">Extremophiles</style></secondary-title><alt-title><style face="normal" font="default" size="100%">Extremophiles</style></alt-title></titles><keywords><keyword><style  face="normal" font="default" size="100%">Citric Acid Cycle</style></keyword><keyword><style  face="normal" font="default" size="100%">Hydrogen-Ion Concentration</style></keyword><keyword><style  face="normal" font="default" size="100%">Kinetics</style></keyword><keyword><style  face="normal" font="default" size="100%">Malate Dehydrogenase</style></keyword><keyword><style  face="normal" font="default" size="100%">Malates</style></keyword><keyword><style  face="normal" font="default" size="100%">Molecular Weight</style></keyword><keyword><style  face="normal" font="default" size="100%">NAD</style></keyword><keyword><style  face="normal" font="default" size="100%">NADP</style></keyword><keyword><style  face="normal" font="default" size="100%">Oxaloacetic Acid</style></keyword><keyword><style  face="normal" font="default" size="100%">Phylogeny</style></keyword><keyword><style  face="normal" font="default" size="100%">Protein Conformation</style></keyword><keyword><style  face="normal" font="default" size="100%">Protein Subunits</style></keyword><keyword><style  face="normal" font="default" size="100%">Pyrobaculum</style></keyword><keyword><style  face="normal" font="default" size="100%">Recombinant Proteins</style></keyword><keyword><style  face="normal" font="default" size="100%">Sequence Analysis, Protein</style></keyword><keyword><style  face="normal" font="default" size="100%">Substrate Specificity</style></keyword><keyword><style  face="normal" font="default" size="100%">Temperature</style></keyword></keywords><dates><year><style  face="normal" font="default" size="100%">2007</style></year><pub-dates><date><style  face="normal" font="default" size="100%">2007 Sep</style></date></pub-dates></dates><volume><style face="normal" font="default" size="100%">11</style></volume><pages><style face="normal" font="default" size="100%">741-6</style></pages><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">&lt;p&gt;Native and recombinant malate dehydrogenase (MDH) was characterized from the hyperthermophilic, facultatively autotrophic archaeon Pyrobaculum islandicum. The enzyme is a homotetramer with a subunit mass of 33 kDa. The activity kinetics of the native and recombinant proteins are the same. The apparent K ( m ) values of the recombinant protein for oxaloacetate (OAA) and NADH (at 80 degrees C and pH 8.0) were 15 and 86 microM, respectively, with specific activity as high as 470 U mg(-1). Activity decreased more than 90% when NADPH was used. The catalytic efficiency of OAA reduction by P. islandicum MDH using NADH was significantly higher than that reported for any other archaeal MDH. Unlike other archaeal MDHs, specific activity of the P. islandicum MDH back-reaction also decreased more than 90% when malate and NAD(+) were used as substrates and was not detected with NADP(+). A phylogenetic tree of 31 archaeal MDHs shows that they fall into 5 distinct groups separated largely along taxonomic lines suggesting minimal lateral mdh transfer between Archaea.&lt;/p&gt;</style></abstract><issue><style face="normal" font="default" size="100%">5</style></issue><custom1><style face="normal" font="default" size="100%">http://www.ncbi.nlm.nih.gov/pubmed/17487443?dopt=Abstract</style></custom1></record><record><source-app name="Biblio" version="7.x">Drupal-Biblio</source-app><ref-type>17</ref-type><contributors><authors><author><style face="normal" font="default" size="100%">Lowy, Daniel A</style></author><author><style face="normal" font="default" size="100%">Tender, Leonard M</style></author><author><style face="normal" font="default" size="100%">Zeikus, J Gregory</style></author><author><style face="normal" font="default" size="100%">Park, Doo Hyun</style></author><author><style face="normal" font="default" size="100%">Lovley, Derek R</style></author></authors></contributors><titles><title><style face="normal" font="default" size="100%">Harvesting energy from the marine sediment-water interface II. Kinetic activity of anode materials.</style></title><secondary-title><style face="normal" font="default" size="100%">Biosens Bioelectron</style></secondary-title><alt-title><style face="normal" font="default" size="100%">Biosens Bioelectron</style></alt-title></titles><keywords><keyword><style  face="normal" font="default" size="100%">Electrochemistry</style></keyword><keyword><style  face="normal" font="default" size="100%">Electrodes</style></keyword><keyword><style  face="normal" font="default" size="100%">Energy-Generating Resources</style></keyword><keyword><style  face="normal" font="default" size="100%">Ferumoxytol</style></keyword><keyword><style  face="normal" font="default" size="100%">Geologic Sediments</style></keyword><keyword><style  face="normal" font="default" size="100%">Kinetics</style></keyword><keyword><style  face="normal" font="default" size="100%">Oceans and Seas</style></keyword><keyword><style  face="normal" font="default" size="100%">Seawater</style></keyword></keywords><dates><year><style  face="normal" font="default" size="100%">2006</style></year><pub-dates><date><style  face="normal" font="default" size="100%">2006 May 15</style></date></pub-dates></dates><volume><style face="normal" font="default" size="100%">21</style></volume><pages><style face="normal" font="default" size="100%">2058-63</style></pages><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">Here, we report a comparative study on the kinetic activity of various anodes of a recently described microbial fuel cell consisting of an anode imbedded in marine sediment and a cathode in overlying seawater. Using plain graphite anodes, it was demonstrated that a significant portion of the anodic current results from oxidation of sediment organic matter catalyzed by microorganisms colonizing the anode and capable of directly reducing the anode without added exogenous electron-transfer mediators. Here, graphite anodes incorporating microbial oxidants are evaluated in the laboratory relative to plain graphite with the goal of increasing power density by increasing current density. Anodes evaluated include graphite modified by adsorption of anthraquinone-1,6-disulfonic acid (AQDS) or 1,4-naphthoquinone (NQ), a graphite-ceramic composite containing Mn2+ and Ni2+, and graphite modified with a graphite paste containing Fe3O4 or Fe3O4 and Ni2+. It was found that these anodes possess between 1.5- and 2.2-fold greater kinetic activity than plain graphite. Fuel cells were deployed in a coastal site near Tuckerton, NJ (USA) that utilized two of these anodes. These fuel cells generated ca. 5-fold greater current density than a previously characterized fuel cell equipped with a plain graphite anode, and operated at the same site.</style></abstract><issue><style face="normal" font="default" size="100%">11</style></issue><custom1><style face="normal" font="default" size="100%">http://www.ncbi.nlm.nih.gov/pubmed/16574400?dopt=Abstract</style></custom1></record><record><source-app name="Biblio" version="7.x">Drupal-Biblio</source-app><ref-type>17</ref-type><contributors><authors><author><style face="normal" font="default" size="100%">Leang, Ching</style></author><author><style face="normal" font="default" size="100%">Adams, L A</style></author><author><style face="normal" font="default" size="100%">Chin, K-J</style></author><author><style face="normal" font="default" size="100%">Nevin, K P</style></author><author><style face="normal" font="default" size="100%">Methé, B A</style></author><author><style face="normal" font="default" size="100%">Webster, J</style></author><author><style face="normal" font="default" size="100%">Sharma, M L</style></author><author><style face="normal" font="default" size="100%">Lovley, D R</style></author></authors></contributors><titles><title><style face="normal" font="default" size="100%">Adaptation to disruption of the electron transfer pathway for Fe(III) reduction in Geobacter sulfurreducens.</style></title><secondary-title><style face="normal" font="default" size="100%">J Bacteriol</style></secondary-title><alt-title><style face="normal" font="default" size="100%">J. Bacteriol.</style></alt-title></titles><keywords><keyword><style  face="normal" font="default" size="100%">Adaptation, Physiological</style></keyword><keyword><style  face="normal" font="default" size="100%">Bacterial Outer Membrane Proteins</style></keyword><keyword><style  face="normal" font="default" size="100%">Base Sequence</style></keyword><keyword><style  face="normal" font="default" size="100%">Cytochromes c</style></keyword><keyword><style  face="normal" font="default" size="100%">DNA Primers</style></keyword><keyword><style  face="normal" font="default" size="100%">Electron Transport</style></keyword><keyword><style  face="normal" font="default" size="100%">Ferric Compounds</style></keyword><keyword><style  face="normal" font="default" size="100%">Gene Expression Regulation, Bacterial</style></keyword><keyword><style  face="normal" font="default" size="100%">Geobacter</style></keyword><keyword><style  face="normal" font="default" size="100%">Kinetics</style></keyword><keyword><style  face="normal" font="default" size="100%">Oxidation-Reduction</style></keyword><keyword><style  face="normal" font="default" size="100%">Reverse Transcriptase Polymerase Chain Reaction</style></keyword></keywords><dates><year><style  face="normal" font="default" size="100%">2005</style></year><pub-dates><date><style  face="normal" font="default" size="100%">2005 Sep</style></date></pub-dates></dates><volume><style face="normal" font="default" size="100%">187</style></volume><pages><style face="normal" font="default" size="100%">5918-26</style></pages><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">Previous studies demonstrated that an outer membrane c-type cytochrome, OmcB, was involved in Fe(III) reduction in Geobacter sulfurreducens. An OmcB-deficient mutant was greatly impaired in its ability to reduce both soluble and insoluble Fe(III). Reintroducing omcB restored the capacity for Fe(III) reduction at a level proportional to the level of OmcB production. Here, we report that the OmcB-deficient mutant gradually adapted to grow on soluble Fe(III) but not insoluble Fe(III). The adapted OmcB-deficient mutant reduced soluble Fe(III) at a rate comparable to that of the wild type, but the cell yield of the mutant was only ca. 60% of that of the wild type under steady-state culturing conditions. Analysis of proteins and transcript levels demonstrated that expression of several membrane-associated cytochromes was higher in the adapted mutant than in the wild type. Further comparison of transcript levels during steady-state growth on Fe(III) citrate with a whole-genome DNA microarray revealed a significant shift in gene expression in an apparent attempt to adapt metabolism to the impaired electron transport to Fe(III). These results demonstrate that, although there are many other membrane-bound c-type cytochromes in G. sulfurreducens, increased expression of these cytochromes cannot completely compensate for the loss of OmcB. The concept that outer membrane cytochromes are promiscuous reductases that are interchangeable in function appears to be incorrect. Furthermore, the results indicate that there may be different mechanisms for electron transfer to soluble Fe(III) and insoluble Fe(III) oxides in G. sulfurreducens, which emphasizes the importance of studying electron transport to the environmentally relevant Fe(III) oxides.</style></abstract><issue><style face="normal" font="default" size="100%">17</style></issue><custom1><style face="normal" font="default" size="100%">http://www.ncbi.nlm.nih.gov/pubmed/16109933?dopt=Abstract</style></custom1></record><record><source-app name="Biblio" version="7.x">Drupal-Biblio</source-app><ref-type>17</ref-type><contributors><authors><author><style face="normal" font="default" size="100%">Bond, Daniel R</style></author><author><style face="normal" font="default" size="100%">Mester, Tünde</style></author><author><style face="normal" font="default" size="100%">Nesbø, Camilla L</style></author><author><style face="normal" font="default" size="100%">Izquierdo-Lopez, Andrea V</style></author><author><style face="normal" font="default" size="100%">Collart, Frank L</style></author><author><style face="normal" font="default" size="100%">Lovley, Derek R</style></author></authors></contributors><titles><title><style face="normal" font="default" size="100%">Characterization of citrate synthase from Geobacter sulfurreducens and evidence for a family of citrate synthases similar to those of eukaryotes throughout the Geobacteraceae.</style></title><secondary-title><style face="normal" font="default" size="100%">Appl Environ Microbiol</style></secondary-title><alt-title><style face="normal" font="default" size="100%">Appl. Environ. Microbiol.</style></alt-title></titles><keywords><keyword><style  face="normal" font="default" size="100%">Amino Acid Sequence</style></keyword><keyword><style  face="normal" font="default" size="100%">Citrate (si)-Synthase</style></keyword><keyword><style  face="normal" font="default" size="100%">Culture Media</style></keyword><keyword><style  face="normal" font="default" size="100%">Deltaproteobacteria</style></keyword><keyword><style  face="normal" font="default" size="100%">DNA, Bacterial</style></keyword><keyword><style  face="normal" font="default" size="100%">Eukaryotic Cells</style></keyword><keyword><style  face="normal" font="default" size="100%">Geobacter</style></keyword><keyword><style  face="normal" font="default" size="100%">Kinetics</style></keyword><keyword><style  face="normal" font="default" size="100%">Molecular Sequence Data</style></keyword><keyword><style  face="normal" font="default" size="100%">Phylogeny</style></keyword><keyword><style  face="normal" font="default" size="100%">Sequence Analysis, DNA</style></keyword></keywords><dates><year><style  face="normal" font="default" size="100%">2005</style></year><pub-dates><date><style  face="normal" font="default" size="100%">2005 Jul</style></date></pub-dates></dates><volume><style face="normal" font="default" size="100%">71</style></volume><pages><style face="normal" font="default" size="100%">3858-65</style></pages><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">Members of the family Geobacteraceae are commonly the predominant Fe(III)-reducing microorganisms in sedimentary environments, as well as on the surface of energy-harvesting electrodes, and are able to effectively couple the oxidation of acetate to the reduction of external electron acceptors. Citrate synthase activity of these organisms is of interest due to its key role in acetate metabolism. Prior sequencing of the genome of Geobacter sulfurreducens revealed a putative citrate synthase sequence related to the citrate synthases of eukaryotes. All citrate synthase activity in G. sulfurreducens could be resolved to a single 49-kDa protein via affinity chromatography. The enzyme was successfully expressed at high levels in Escherichia coli with similar properties as the native enzyme, and kinetic parameters were comparable to related citrate synthases (kcat= 8.3 s(-1); Km= 14.1 and 4.3 microM for acetyl coenzyme A and oxaloacetate, respectively). The enzyme was dimeric and was slightly inhibited by ATP (Ki= 1.9 mM for acetyl coenzyme A), which is a known inhibitor for many eukaryotic, dimeric citrate synthases. NADH, an allosteric inhibitor of prokaryotic hexameric citrate synthases, did not affect enzyme activity. Unlike most prokaryotic dimeric citrate synthases, the enzyme did not have any methylcitrate synthase activity. A unique feature of the enzyme, in contrast to citrate synthases from both eukaryotes and prokaryotes, was a lack of stimulation by K+ ions. Similar citrate synthase sequences were detected in a diversity of other Geobacteraceae members. This first characterization of a eukaryotic-like citrate synthase from a prokaryote provides new insight into acetate metabolism in Geobacteraceae members and suggests a molecular target for tracking the presence and activity of these organisms in the environment.</style></abstract><issue><style face="normal" font="default" size="100%">7</style></issue><custom1><style face="normal" font="default" size="100%">http://www.ncbi.nlm.nih.gov/pubmed/16000798?dopt=Abstract</style></custom1></record><record><source-app name="Biblio" version="7.x">Drupal-Biblio</source-app><ref-type>17</ref-type><contributors><authors><author><style face="normal" font="default" size="100%">Mehta, T</style></author><author><style face="normal" font="default" size="100%">Coppi, M V</style></author><author><style face="normal" font="default" size="100%">Childers, S E</style></author><author><style face="normal" font="default" size="100%">Lovley, D R</style></author></authors></contributors><titles><title><style face="normal" font="default" size="100%">Outer membrane c-type cytochromes required for Fe(III) and Mn(IV) oxide reduction in Geobacter sulfurreducens.</style></title><secondary-title><style face="normal" font="default" size="100%">Appl Environ Microbiol</style></secondary-title><alt-title><style face="normal" font="default" size="100%">Appl. Environ. Microbiol.</style></alt-title></titles><keywords><keyword><style  face="normal" font="default" size="100%">Amino Acid Sequence</style></keyword><keyword><style  face="normal" font="default" size="100%">Bacterial Outer Membrane Proteins</style></keyword><keyword><style  face="normal" font="default" size="100%">Bacterial Proteins</style></keyword><keyword><style  face="normal" font="default" size="100%">Base Sequence</style></keyword><keyword><style  face="normal" font="default" size="100%">Cytochromes c</style></keyword><keyword><style  face="normal" font="default" size="100%">DNA Primers</style></keyword><keyword><style  face="normal" font="default" size="100%">Ferric Compounds</style></keyword><keyword><style  face="normal" font="default" size="100%">Geobacter</style></keyword><keyword><style  face="normal" font="default" size="100%">Kinetics</style></keyword><keyword><style  face="normal" font="default" size="100%">Manganese Compounds</style></keyword><keyword><style  face="normal" font="default" size="100%">Molecular Sequence Data</style></keyword><keyword><style  face="normal" font="default" size="100%">Oxidation-Reduction</style></keyword><keyword><style  face="normal" font="default" size="100%">Oxides</style></keyword><keyword><style  face="normal" font="default" size="100%">Peptide Fragments</style></keyword></keywords><dates><year><style  face="normal" font="default" size="100%">2005</style></year><pub-dates><date><style  face="normal" font="default" size="100%">2005 Dec</style></date></pub-dates></dates><volume><style face="normal" font="default" size="100%">71</style></volume><pages><style face="normal" font="default" size="100%">8634-41</style></pages><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">The potential role of outer membrane proteins in electron transfer to insoluble Fe(III) oxides by Geobacter sulfurreducens was investigated because this organism is closely related to the Fe(III) oxide-reducing organisms that are predominant in many Fe(III)-reducing environments. Two of the most abundant proteins that were easily sheared from the outer surfaces of intact cells were c-type cytochromes. One, designated OmcS, has a molecular mass of ca. 50 kDa and is predicted to be an outer membrane hexaheme c-type cytochrome. Transcripts for omcS could be detected during growth on Fe(III) oxide, but not on soluble Fe(III) citrate. The omcS mRNA consisted primarily of a monocistronic transcript, and to a lesser extent, a longer transcript that also contained the downstream gene omcT, which is predicted to encode a second hexaheme outer membrane cytochrome with 62.6% amino acid sequence identity to OmcS. The other abundant c-type cytochrome sheared from the outer surface of G. sulfurreducens, designated OmcE, has a molecular mass of ca. 30 kDa and is predicted to be an outer membrane tetraheme c-type cytochrome. When either omcS or omcE was deleted, G. sulfurreducens could no longer reduce Fe(III) oxide but could still reduce soluble electron acceptors, including Fe(III) citrate. The mutants could reduce Fe(III) in Fe(III) oxide medium only if the Fe(III) chelator, nitrilotriacetic acid, or the electron shuttle, anthraquinone 2,6-disulfonate, was added. Expressing omcS or omcE in trans restored the capacity for Fe(III) oxide reduction. OmcT was not detected among the sheared proteins, and genetic studies indicated that G. sulfurreducens could not reduce Fe(III) oxide when omcT was expressed but OmcS was absent. In contrast, Fe(III) oxide was reduced when omcS was expressed in the absence of OmcT. These results suggest that OmcS and OmcE are involved in electron transfer to Fe(III) oxides in G. sulfurreducens. They also emphasize the importance of evaluating mechanisms for Fe(III) reduction with environmentally relevant Fe(III) oxide, rather than the more commonly utilized Fe(III) citrate, because additional electron transfer components are required for Fe(III) oxide reduction that are not required for Fe(III) citrate reduction.</style></abstract><issue><style face="normal" font="default" size="100%">12</style></issue><custom1><style face="normal" font="default" size="100%">http://www.ncbi.nlm.nih.gov/pubmed/16332857?dopt=Abstract</style></custom1></record><record><source-app name="Biblio" version="7.x">Drupal-Biblio</source-app><ref-type>17</ref-type><contributors><authors><author><style face="normal" font="default" size="100%">Chin, Kuk-Jeong</style></author><author><style face="normal" font="default" size="100%">Esteve-Núñez, Abraham</style></author><author><style face="normal" font="default" size="100%">Leang, Ching</style></author><author><style face="normal" font="default" size="100%">Lovley, Derek R</style></author></authors></contributors><titles><title><style face="normal" font="default" size="100%">Direct correlation between rates of anaerobic respiration and levels of mRNA for key respiratory genes in Geobacter sulfurreducens.</style></title><secondary-title><style face="normal" font="default" size="100%">Appl Environ Microbiol</style></secondary-title><alt-title><style face="normal" font="default" size="100%">Appl. Environ. Microbiol.</style></alt-title></titles><keywords><keyword><style  face="normal" font="default" size="100%">Anaerobiosis</style></keyword><keyword><style  face="normal" font="default" size="100%">Base Sequence</style></keyword><keyword><style  face="normal" font="default" size="100%">DNA Primers</style></keyword><keyword><style  face="normal" font="default" size="100%">Geobacter</style></keyword><keyword><style  face="normal" font="default" size="100%">Kinetics</style></keyword><keyword><style  face="normal" font="default" size="100%">Oxygen Consumption</style></keyword><keyword><style  face="normal" font="default" size="100%">Polymerase Chain Reaction</style></keyword><keyword><style  face="normal" font="default" size="100%">RNA, Messenger</style></keyword></keywords><dates><year><style  face="normal" font="default" size="100%">2004</style></year><pub-dates><date><style  face="normal" font="default" size="100%">2004 Sep</style></date></pub-dates></dates><volume><style face="normal" font="default" size="100%">70</style></volume><pages><style face="normal" font="default" size="100%">5183-9</style></pages><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">The predominance of Geobacter species in environments in which Fe(III) reduction is important has suggested that Fe(III) reduction rates might be estimated in Geobacter-dominated environments by assessing in situ activity with molecular techniques. To determine whether mRNA levels of key respiratory genes might be correlated with respiration rates in Geobacter sulfurreducens, studies were conducted with fumarate as the electron acceptor and acetate as the limiting electron donor in anaerobic continuous cultures. Levels of mRNA for a fumarate reductase gene, frdA, quantified by real-time reverse transcription-PCR were directly correlated with fumarate reduction rates. In similar studies with Fe(III) as the electron acceptor, mRNA levels for omcB, a gene for an outer membrane c-type cytochrome involved in Fe(III) reduction, were positively correlated with Fe(III) reduction rates. Levels of mRNA for frdA and omcB were also positively correlated with fumarate and Fe(III) reduction rates, respectively, when growth was limited by the availability of fumarate or Fe(III), but mRNA levels were higher than in acetate-limited cultures. Levels of mRNA for omcC, which encodes a c-type cytochrome highly similar to OmcB but not necessary for Fe(III) reduction, followed patterns different than those of omcB. This agrees with the previous finding that OmcC is not involved in Fe(III) reduction and suggests that changes in mRNA levels of omcB are related to its role in Fe(III) reduction. These results demonstrate that mRNA levels for respiratory genes might be used to estimate in situ Fe(III) reduction rates in Geobacter-dominated environments but suggest that information on environmental conditions and/or the metabolic state of Geobacter species is also required for accurate rate estimates.</style></abstract><issue><style face="normal" font="default" size="100%">9</style></issue><custom1><style face="normal" font="default" size="100%">http://www.ncbi.nlm.nih.gov/pubmed/15345398?dopt=Abstract</style></custom1></record><record><source-app name="Biblio" version="7.x">Drupal-Biblio</source-app><ref-type>17</ref-type><contributors><authors><author><style face="normal" font="default" size="100%">Gregory, Kelvin B</style></author><author><style face="normal" font="default" size="100%">Bond, Daniel R</style></author><author><style face="normal" font="default" size="100%">Lovley, Derek R</style></author></authors></contributors><titles><title><style face="normal" font="default" size="100%">Graphite electrodes as electron donors for anaerobic respiration.</style></title><secondary-title><style face="normal" font="default" size="100%">Environ Microbiol</style></secondary-title><alt-title><style face="normal" font="default" size="100%">Environ. Microbiol.</style></alt-title></titles><keywords><keyword><style  face="normal" font="default" size="100%">Anaerobiosis</style></keyword><keyword><style  face="normal" font="default" size="100%">Electrodes</style></keyword><keyword><style  face="normal" font="default" size="100%">Electrons</style></keyword><keyword><style  face="normal" font="default" size="100%">Fumarates</style></keyword><keyword><style  face="normal" font="default" size="100%">Geobacter</style></keyword><keyword><style  face="normal" font="default" size="100%">Geologic Sediments</style></keyword><keyword><style  face="normal" font="default" size="100%">Graphite</style></keyword><keyword><style  face="normal" font="default" size="100%">Kinetics</style></keyword><keyword><style  face="normal" font="default" size="100%">Microscopy, Electron, Scanning</style></keyword><keyword><style  face="normal" font="default" size="100%">Nitrates</style></keyword><keyword><style  face="normal" font="default" size="100%">Phylogeny</style></keyword><keyword><style  face="normal" font="default" size="100%">RNA, Ribosomal, 16S</style></keyword><keyword><style  face="normal" font="default" size="100%">Sequence Analysis, DNA</style></keyword></keywords><dates><year><style  face="normal" font="default" size="100%">2004</style></year><pub-dates><date><style  face="normal" font="default" size="100%">2004 Jun</style></date></pub-dates></dates><volume><style face="normal" font="default" size="100%">6</style></volume><pages><style face="normal" font="default" size="100%">596-604</style></pages><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">It has been demonstrated previously that Geobacter species can transfer electrons directly to electrodes. In order to determine whether electrodes could serve as electron donors for microbial respiration, enrichment cultures were established from a sediment inoculum with a potentiostat-poised graphite electrode as the sole electron donor and nitrate as the electron acceptor. Nitrate was reduced to nitrite with the consumption of electrical current. The stoichiometry of electron and nitrate consumption and nitrite accumulation were consistent with the electrode serving as the sole electron donor for nitrate reduction. Analysis of 16 rRNA gene sequences demonstrated that the electrodes supplied with current were specifically enriched in microorganisms with sequences most closely related to the sequences of known Geobacter species. A pure culture of Geobacter metallireducens was shown to reduce nitrate to nitrite with the electrode as the sole electron donor with the expected stoichiometry of electron consumption. Cells attached to the electrode appeared to be responsible for the nitrate reduction. Attached cells of Geobacter sulfurreducens reduced fumarate to succinate with the electrode as an electron donor. These results demonstrate for the first time that electrodes may serve as a direct electron donor for anaerobic respiration. This finding has implications for the harvesting of electricity from anaerobic sediments and the bioremediation of oxidized contaminants.</style></abstract><issue><style face="normal" font="default" size="100%">6</style></issue><custom1><style face="normal" font="default" size="100%">http://www.ncbi.nlm.nih.gov/pubmed/15142248?dopt=Abstract</style></custom1></record><record><source-app name="Biblio" version="7.x">Drupal-Biblio</source-app><ref-type>17</ref-type><contributors><authors><author><style face="normal" font="default" size="100%">Zhang, Shiming</style></author><author><style face="normal" font="default" size="100%">Kolvek, Steven</style></author><author><style face="normal" font="default" size="100%">Goodwin, Steve</style></author><author><style face="normal" font="default" size="100%">Lenz, Robert W</style></author></authors></contributors><titles><title><style face="normal" font="default" size="100%">Poly(hydroxyalkanoic acid) Biosynthesis in Ectothiorhodospirashaposhnikovii: Characterization and Reactivity of a Type III PHA Synthase.</style></title><secondary-title><style face="normal" font="default" size="100%">Biomacromolecules</style></secondary-title><alt-title><style face="normal" font="default" size="100%">Biomacromolecules</style></alt-title></titles><keywords><keyword><style  face="normal" font="default" size="100%">Acyltransferases</style></keyword><keyword><style  face="normal" font="default" size="100%">Cloning, Molecular</style></keyword><keyword><style  face="normal" font="default" size="100%">Ectothiorhodospira shaposhnikovii</style></keyword><keyword><style  face="normal" font="default" size="100%">Escherichia coli</style></keyword><keyword><style  face="normal" font="default" size="100%">Hydroxybutyrates</style></keyword><keyword><style  face="normal" font="default" size="100%">Kinetics</style></keyword><keyword><style  face="normal" font="default" size="100%">Molecular Weight</style></keyword><keyword><style  face="normal" font="default" size="100%">Polyesters</style></keyword></keywords><dates><year><style  face="normal" font="default" size="100%">2004</style></year><pub-dates><date><style  face="normal" font="default" size="100%">2004 Jan-Feb</style></date></pub-dates></dates><volume><style face="normal" font="default" size="100%">5</style></volume><pages><style face="normal" font="default" size="100%">40-8</style></pages><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">Ectothiorhodospira shaposhnikovii is able to accumulate polyhydroxybutyrate (PHB) photoautotrophically during nitrogen-limited growth. The activity of polyhydroxyalkanoate (PHA) synthase in the cells correlates with PHB accumulation. PHA synthase samples collected during the light period do not show a lag phase during in vitro polymerization. Synthase samples collected in the dark period displays a significant lag phase during in vitro polymerization. The lag phase can be eliminated by reacting the PHA synthase with the monomer, 3-hydroxybutyryl-CoA (3HBCoA). The PHA synthase genes (phaC and phaE) were cloned by screening a genomic library for PHA accumulation in E. coli cells. The PHA synthase expressed in the recombinant E. coli cells was purified to homogeneity. Both sequence analysis and biochemical studies indicated that this PHA synthase consists of two subunits, PhaE and PhaC and, therefore, belongs to the type III PHA synthases. Two major complexes were identified in preparations of purified PHA synthase. The large complex appears to be composed of 12 PhaC subunits and 12 PhaE subunits (dodecamer), whereas the small complex appears to be composed of 6 PhaC and 6 PhaE subunits (hexamer). In dilute aqueous solution, the synthase is predominantly composed of hexamer and has low activity accompanied with a significant lag period at the initial stage of reaction. The percentage of dodecameric complex increases with increasing salt concentration. The dodecameric complex has a greatly increased specific activity for the polymerization of 3HBCoA and a negligible lag period. The results from in vitro polymerizations of 3HBCoA suggest that the PHA synthase from E. shaposhnikovii may catalyze a living polymerization and demonstrate that two PhaC and two PhaE subunits comprise a single catalytic site in the synthase complex.</style></abstract><issue><style face="normal" font="default" size="100%">1</style></issue><custom1><style face="normal" font="default" size="100%">http://www.ncbi.nlm.nih.gov/pubmed/14715006?dopt=Abstract</style></custom1></record><record><source-app name="Biblio" version="7.x">Drupal-Biblio</source-app><ref-type>17</ref-type><contributors><authors><author><style face="normal" font="default" size="100%">Griffith, Kevin L</style></author><author><style face="normal" font="default" size="100%">Shah, Ishita M</style></author><author><style face="normal" font="default" size="100%">Wolf, Richard E</style></author></authors></contributors><titles><title><style face="normal" font="default" size="100%">Proteolytic degradation of Escherichia coli transcription activators SoxS and MarA as the mechanism for reversing the induction of the superoxide (SoxRS) and multiple antibiotic resistance (Mar) regulons.</style></title><secondary-title><style face="normal" font="default" size="100%">Mol Microbiol</style></secondary-title><alt-title><style face="normal" font="default" size="100%">Mol. Microbiol.</style></alt-title></titles><keywords><keyword><style  face="normal" font="default" size="100%">Base Sequence</style></keyword><keyword><style  face="normal" font="default" size="100%">Blotting, Western</style></keyword><keyword><style  face="normal" font="default" size="100%">DNA Primers</style></keyword><keyword><style  face="normal" font="default" size="100%">DNA-Binding Proteins</style></keyword><keyword><style  face="normal" font="default" size="100%">Drug Resistance, Bacterial</style></keyword><keyword><style  face="normal" font="default" size="100%">Drug Resistance, Multiple, Bacterial</style></keyword><keyword><style  face="normal" font="default" size="100%">Endopeptidases</style></keyword><keyword><style  face="normal" font="default" size="100%">Escherichia coli</style></keyword><keyword><style  face="normal" font="default" size="100%">Escherichia coli Proteins</style></keyword><keyword><style  face="normal" font="default" size="100%">Genes, Bacterial</style></keyword><keyword><style  face="normal" font="default" size="100%">Half-Life</style></keyword><keyword><style  face="normal" font="default" size="100%">Hydrolysis</style></keyword><keyword><style  face="normal" font="default" size="100%">Kinetics</style></keyword><keyword><style  face="normal" font="default" size="100%">Mutation</style></keyword><keyword><style  face="normal" font="default" size="100%">Oxidation-Reduction</style></keyword><keyword><style  face="normal" font="default" size="100%">Promoter Regions, Genetic</style></keyword><keyword><style  face="normal" font="default" size="100%">Regulon</style></keyword><keyword><style  face="normal" font="default" size="100%">Trans-Activators</style></keyword><keyword><style  face="normal" font="default" size="100%">Transcription, Genetic</style></keyword></keywords><dates><year><style  face="normal" font="default" size="100%">2004</style></year><pub-dates><date><style  face="normal" font="default" size="100%">2004 Mar</style></date></pub-dates></dates><volume><style face="normal" font="default" size="100%">51</style></volume><pages><style face="normal" font="default" size="100%">1801-16</style></pages><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">In Escherichia coli, the SoxRS regulon confers resistance to redox-cycling compounds, and the Mar regulon provides a defence against multiple antibiotics. The response regulators, SoxS and MarA, are synthesized de novo in response to their inducing signals and directly activate transcription of a common set of target genes. Although the mechanisms of transcription activation by SoxS and MarA have been well studied, little is known about how the systems are shut-off once the inducing stress has subsided, except that de novo synthesis of the regulators is known to cease almost immediately. Here, we induced the SoxRS regulon and determined that, upon removal of the inducer, expression of the regulon's genes quickly returns to the preinduced level. This rapid shut-off indicates that the system is reset by an active process. We found that SoxS is unstable and infer that SoxS degradation is responsible for the rapid return of the system to the ground state upon removal of the inducing signal. We also found that MarA is unstable and that the instability of both proteins is intrinsic and unregulated. We used null mutations of protease genes to identify the proteases involved in the degradation of SoxS and MarA. Among single protease mutations, only lon mutations increased the half-life of SoxS and MarA. In addition, SoxS appeared to be nearly completely stable in a lon ftsH double mutant. Using hexahistidine tags placed at the respective ends of the activators, we found that access to the amino-terminus is essential for the proteolytic degradation.</style></abstract><issue><style face="normal" font="default" size="100%">6</style></issue><custom1><style face="normal" font="default" size="100%">http://www.ncbi.nlm.nih.gov/pubmed/15009903?dopt=Abstract</style></custom1></record><record><source-app name="Biblio" version="7.x">Drupal-Biblio</source-app><ref-type>17</ref-type><contributors><authors><author><style face="normal" font="default" size="100%">Griffith, Kevin L</style></author><author><style face="normal" font="default" size="100%">Shah, Ishita M</style></author><author><style face="normal" font="default" size="100%">Myers, Todd E</style></author><author><style face="normal" font="default" size="100%">O'Neill, Michael C</style></author><author><style face="normal" font="default" size="100%">Wolf, Richard E</style></author></authors></contributors><titles><title><style face="normal" font="default" size="100%">Evidence for &quot;pre-recruitment&quot; as a new mechanism of transcription activation in Escherichia coli: the large excess of SoxS binding sites per cell relative to the number of SoxS molecules per cell.</style></title><secondary-title><style face="normal" font="default" size="100%">Biochem Biophys Res Commun</style></secondary-title><alt-title><style face="normal" font="default" size="100%">Biochem. Biophys. Res. Commun.</style></alt-title></titles><keywords><keyword><style  face="normal" font="default" size="100%">Bacterial Proteins</style></keyword><keyword><style  face="normal" font="default" size="100%">Binding Sites</style></keyword><keyword><style  face="normal" font="default" size="100%">Blotting, Western</style></keyword><keyword><style  face="normal" font="default" size="100%">Cell Division</style></keyword><keyword><style  face="normal" font="default" size="100%">DNA-Binding Proteins</style></keyword><keyword><style  face="normal" font="default" size="100%">Escherichia coli</style></keyword><keyword><style  face="normal" font="default" size="100%">Escherichia coli Proteins</style></keyword><keyword><style  face="normal" font="default" size="100%">Gene Expression Regulation, Bacterial</style></keyword><keyword><style  face="normal" font="default" size="100%">Genome, Bacterial</style></keyword><keyword><style  face="normal" font="default" size="100%">Kinetics</style></keyword><keyword><style  face="normal" font="default" size="100%">Numerical Analysis, Computer-Assisted</style></keyword><keyword><style  face="normal" font="default" size="100%">Oxidative Stress</style></keyword><keyword><style  face="normal" font="default" size="100%">Paraquat</style></keyword><keyword><style  face="normal" font="default" size="100%">Protein Transport</style></keyword><keyword><style  face="normal" font="default" size="100%">Trans-Activators</style></keyword><keyword><style  face="normal" font="default" size="100%">Transcription Factors</style></keyword><keyword><style  face="normal" font="default" size="100%">Transcriptional Activation</style></keyword></keywords><dates><year><style  face="normal" font="default" size="100%">2002</style></year><pub-dates><date><style  face="normal" font="default" size="100%">2002 Mar 8</style></date></pub-dates></dates><volume><style face="normal" font="default" size="100%">291</style></volume><pages><style face="normal" font="default" size="100%">979-86</style></pages><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">In response to the oxidative stress imposed by redox-cycling compounds like paraquat, Escherichia coli induces the synthesis of SoxS, which then activates the transcription of approximately 100 genes. The DNA binding site for SoxS-dependent transcription activation, the &quot;soxbox,&quot; is highly degenerate, suggesting that the genome contains a large number of SoxS binding sites. To estimate the number of soxboxes in the cell, we searched the E. coli genome for SoxS binding sites using as query sequence the previously determined optimal SoxS binding sequence. We found approximately 12,500 sequences that match the optimal binding sequence under the conditions of our search; this agrees with our previous estimate, based on information theory, that a random sequence the size of the E. coli genome contains approximately 13,000 soxboxes. Thus, fast-growing cells with 4-6 genomes per cell have approximately 65,000 soxboxes. This large number of potential SoxS binding sites per cell raises the interesting question of how SoxS distinguishes between the functional soxboxes located within the promoters of target genes and the plethora of equivalent but nonfunctional binding sites scattered throughout the chromosome. To address this question, we treated cells with paraquat and used Western blot analysis to determine the kinetics of SoxS accumulation per cell; we also determined the kinetics of SoxS-activated gene expression. The abundance of SoxS reached a maximum of 2,500 molecules per cell 20 min after induction and gradually declined to approximately 500 molecules per cell over the next 1.5 h. Given that activation of target gene expression began almost immediately and given the large disparity between the number of SoxS molecules per cell, 2,500, and the number of SoxS binding sites per cell, 65,000, we infer that SoxS is not likely to activate transcription by the usual &quot;recruitment&quot; pathway, as this mechanism would require a number of SoxS molecules similar to the number of soxboxes. Instead, we propose that SoxS first interacts in solution with RNA polymerase and then the binary complex scans the chromosome for promoters that contain a soxbox properly positioned and oriented for transcription activation. We name this new pathway &quot;pre-recruitment.&quot;</style></abstract><issue><style face="normal" font="default" size="100%">4</style></issue><custom1><style face="normal" font="default" size="100%">http://www.ncbi.nlm.nih.gov/pubmed/11866462?dopt=Abstract</style></custom1></record><record><source-app name="Biblio" version="7.x">Drupal-Biblio</source-app><ref-type>17</ref-type><contributors><authors><author><style face="normal" font="default" size="100%">Elkhaimi, M</style></author><author><style face="normal" font="default" size="100%">Kaadige, M R</style></author><author><style face="normal" font="default" size="100%">Kamath, D</style></author><author><style face="normal" font="default" size="100%">Jackson, J C</style></author><author><style face="normal" font="default" size="100%">Biliran, H</style></author><author><style face="normal" font="default" size="100%">Lopes, J M</style></author></authors></contributors><titles><title><style face="normal" font="default" size="100%">Combinatorial regulation of phospholipid biosynthetic gene expression by the UME6, SIN3 and RPD3 genes.</style></title><secondary-title><style face="normal" font="default" size="100%">Nucleic Acids Res</style></secondary-title><alt-title><style face="normal" font="default" size="100%">Nucleic Acids Res.</style></alt-title></titles><keywords><keyword><style  face="normal" font="default" size="100%">Basic Helix-Loop-Helix Transcription Factors</style></keyword><keyword><style  face="normal" font="default" size="100%">DNA-Binding Proteins</style></keyword><keyword><style  face="normal" font="default" size="100%">Fungal Proteins</style></keyword><keyword><style  face="normal" font="default" size="100%">Gene Expression Regulation, Fungal</style></keyword><keyword><style  face="normal" font="default" size="100%">Helix-Loop-Helix Motifs</style></keyword><keyword><style  face="normal" font="default" size="100%">Histone Deacetylases</style></keyword><keyword><style  face="normal" font="default" size="100%">Kinetics</style></keyword><keyword><style  face="normal" font="default" size="100%">Phospholipids</style></keyword><keyword><style  face="normal" font="default" size="100%">Repressor Proteins</style></keyword><keyword><style  face="normal" font="default" size="100%">Saccharomyces cerevisiae</style></keyword><keyword><style  face="normal" font="default" size="100%">Saccharomyces cerevisiae Proteins</style></keyword><keyword><style  face="normal" font="default" size="100%">Transcription Factors</style></keyword><keyword><style  face="normal" font="default" size="100%">Transcription, Genetic</style></keyword></keywords><dates><year><style  face="normal" font="default" size="100%">2000</style></year><pub-dates><date><style  face="normal" font="default" size="100%">2000 Aug 15</style></date></pub-dates></dates><volume><style face="normal" font="default" size="100%">28</style></volume><pages><style face="normal" font="default" size="100%">3160-7</style></pages><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">The Ume6p-Sin3p-Rpd3p complex negatively regulates expression of genes containing a Ume6p binding site. However, these regulatory proteins also function independently to regulate gene expression both negatively and positively. The model system for this combinatorial regulation is the yeast phospholipid biosynthetic pathway. Sin3p negatively regulates the INO1, CHO1, CHO2 and OPI3 genes while Ume6p negatively regulates the INO1 gene and positively regulates the other genes. We have suggested that the positive regulation results from indirect effects on expression of the INO2 transcriptional activator gene. Here, we demonstrate that the effect of Ume6p on INO2 gene expression is also indirect. We also show that Rpd3p is a negative regulator of phospholipid biosynthetic gene expression. The ability of Ume6p, Sin3p and Rpd3p to differentially regulate expression of the phospholipid biosynthetic genes affects phospholipid composition. A sin3 mutant strain lacks detectable levels of phosphatidylethanolamine and elevated levels of phosphatidylcholine (PC) and a rpd3 mutant strain has reduced levels of PC. These alterations in membrane composition suggest that there may exist additional differences in regulation of phospholipid biosynthetic gene expression and that membrane compositions may be coordinated with other biological processes regulated by Ume6p, Sin3p and Rpd3p.</style></abstract><issue><style face="normal" font="default" size="100%">16</style></issue><custom1><style face="normal" font="default" size="100%">http://www.ncbi.nlm.nih.gov/pubmed/10931932?dopt=Abstract</style></custom1></record><record><source-app name="Biblio" version="7.x">Drupal-Biblio</source-app><ref-type>17</ref-type><contributors><authors><author><style face="normal" font="default" size="100%">Scherer, T M</style></author><author><style face="normal" font="default" size="100%">Fuller, R C</style></author><author><style face="normal" font="default" size="100%">Goodwin, S</style></author><author><style face="normal" font="default" size="100%">Lenz, R W</style></author></authors></contributors><titles><title><style face="normal" font="default" size="100%">Enzymatic hydrolysis of oligomeric models of poly-3-hydroxybutyrate.</style></title><secondary-title><style face="normal" font="default" size="100%">Biomacromolecules</style></secondary-title><alt-title><style face="normal" font="default" size="100%">Biomacromolecules</style></alt-title></titles><keywords><keyword><style  face="normal" font="default" size="100%">3-Hydroxybutyric Acid</style></keyword><keyword><style  face="normal" font="default" size="100%">Alcaligenes</style></keyword><keyword><style  face="normal" font="default" size="100%">Aspergillus fumigatus</style></keyword><keyword><style  face="normal" font="default" size="100%">Carboxylic Ester Hydrolases</style></keyword><keyword><style  face="normal" font="default" size="100%">Escherichia coli</style></keyword><keyword><style  face="normal" font="default" size="100%">Hydrolysis</style></keyword><keyword><style  face="normal" font="default" size="100%">Kinetics</style></keyword><keyword><style  face="normal" font="default" size="100%">Macrolides</style></keyword><keyword><style  face="normal" font="default" size="100%">Models, Chemical</style></keyword><keyword><style  face="normal" font="default" size="100%">Polymers</style></keyword></keywords><dates><year><style  face="normal" font="default" size="100%">2000</style></year><pub-dates><date><style  face="normal" font="default" size="100%">2000 Winter</style></date></pub-dates></dates><volume><style face="normal" font="default" size="100%">1</style></volume><pages><style face="normal" font="default" size="100%">577-83</style></pages><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">The mechanism of the enzymatic degradation of poly([R]-3-hydroxybutyrate) (PHB) was investigated by using well-defined model substrates, including both linear and cyclic [R]-3-hydroxybutyrate (3HB) and [R]-3-hydroxyvalerate (3HV) oligomers, with two different PHB depolymerases. The linear and cyclic oligomers containing from 2 to 10 repeating units were hydrolyzed in solutions of the depolymerase isolated from Aspergillus fumigatus and Alcaligenes faecalis, and the rates of hydrolysis and types of products formed were characterized. Both of the depolymerases catalyzed the hydrolysis of the cyclic oligomers (macrolides) which contained more than three 3HB and 3HV repeating units. The degradation reactions of the linear and cyclic 3HB oligomers with the A. fumigatus depolymerase gave similar ratios of monomer-to-dimer products, but PHB itself formed mostly monomer on hydrolysis, indicating that the enzymatic hydrolysis reactions occurred by different mechanisms for these different types of substrates. The results of this study conclusively show that at least the endo mode of polymer hydrolysis occurs with the two enzymes studied, while the A. fumigatus depolymerase was found to utilize both endo and exo modes of hydrolysis to efficiently degrade PHB and 3HB oligomers.</style></abstract><issue><style face="normal" font="default" size="100%">4</style></issue><custom1><style face="normal" font="default" size="100%">http://www.ncbi.nlm.nih.gov/pubmed/11710184?dopt=Abstract</style></custom1></record><record><source-app name="Biblio" version="7.x">Drupal-Biblio</source-app><ref-type>17</ref-type><contributors><authors><author><style face="normal" font="default" size="100%">Song, J J</style></author><author><style face="normal" font="default" size="100%">Zhang, S</style></author><author><style face="normal" font="default" size="100%">Lenz, R W</style></author><author><style face="normal" font="default" size="100%">Goodwin, S</style></author></authors></contributors><titles><title><style face="normal" font="default" size="100%">In vitro polymerization and copolymerization of 3-hydroxypropionyl-CoA with the PHB synthase from Ralstonia eutropha.</style></title><secondary-title><style face="normal" font="default" size="100%">Biomacromolecules</style></secondary-title><alt-title><style face="normal" font="default" size="100%">Biomacromolecules</style></alt-title></titles><keywords><keyword><style  face="normal" font="default" size="100%">Acyltransferases</style></keyword><keyword><style  face="normal" font="default" size="100%">Coenzyme A</style></keyword><keyword><style  face="normal" font="default" size="100%">Escherichia coli</style></keyword><keyword><style  face="normal" font="default" size="100%">Kinetics</style></keyword><keyword><style  face="normal" font="default" size="100%">Magnetic Resonance Spectroscopy</style></keyword><keyword><style  face="normal" font="default" size="100%">Molecular Weight</style></keyword></keywords><dates><year><style  face="normal" font="default" size="100%">2000</style></year><pub-dates><date><style  face="normal" font="default" size="100%">2000 Fall</style></date></pub-dates></dates><volume><style face="normal" font="default" size="100%">1</style></volume><pages><style face="normal" font="default" size="100%">433-9</style></pages><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">The poly(3-hydroxybutyrate) (PHB) synthase of Ralstonia eutropha, which was produced by a recombinant strain of Escherichia coli and purified in one step with a methyl-HIC column to a purity of more than 90%, was used to polymerize 3-hydroxypropionyl-CoA (3HPCoA) and to copolymerize 3HPCoA with 3-hydroxybutyryl-CoA (3HBCoA). A Km of 189 microM and a kcat of 10 s-1 were determined for the activity of the enzyme in the polymerization reaction of 3HPCoA based on the assumption that the dimer form of PHB synthase was the active form. Free coenzyme A was found to be a very effective competitive inhibitor for the polymerization of 3HPCoA with a Ki of 85 microM. The maximum degree of conversion of 3HPCoA to polymer was less than 40%. In the simultaneous copolymerization reactions of these two monomers, both the turnover number for the copolymerization reaction and the maximum degree of conversion of 3HPCoA and 3HBCoA to copolymers increased with an increase in the amount of 3HBCoA in the monomer mixture. However, the maximum conversion of 3HPCoA to copolymer was always less than 35%, regardless of the ratio of 3HPCoA to 3HBCoA. Block copolymers were obtained by the sequential copolymerization of the two monomers and these copolymers had a much narrower molecular weight distribution than those obtained by the simultaneous copolymerization for the same molar ratio of 3HPCoA to 3HBCoA.</style></abstract><issue><style face="normal" font="default" size="100%">3</style></issue><custom1><style face="normal" font="default" size="100%">http://www.ncbi.nlm.nih.gov/pubmed/11710134?dopt=Abstract</style></custom1></record><record><source-app name="Biblio" version="7.x">Drupal-Biblio</source-app><ref-type>17</ref-type><contributors><authors><author><style face="normal" font="default" size="100%">Zhang, S</style></author><author><style face="normal" font="default" size="100%">Yasuo, T</style></author><author><style face="normal" font="default" size="100%">Lenz, R W</style></author><author><style face="normal" font="default" size="100%">Goodwin, S</style></author></authors></contributors><titles><title><style face="normal" font="default" size="100%">Kinetic and mechanistic characterization of the polyhydroxybutyrate synthase from Ralstonia eutropha.</style></title><secondary-title><style face="normal" font="default" size="100%">Biomacromolecules</style></secondary-title><alt-title><style face="normal" font="default" size="100%">Biomacromolecules</style></alt-title></titles><keywords><keyword><style  face="normal" font="default" size="100%">Acyltransferases</style></keyword><keyword><style  face="normal" font="default" size="100%">Catalysis</style></keyword><keyword><style  face="normal" font="default" size="100%">Chromatography, Gel</style></keyword><keyword><style  face="normal" font="default" size="100%">Coenzyme A</style></keyword><keyword><style  face="normal" font="default" size="100%">Culture Media</style></keyword><keyword><style  face="normal" font="default" size="100%">Hydrogen-Ion Concentration</style></keyword><keyword><style  face="normal" font="default" size="100%">Kinetics</style></keyword><keyword><style  face="normal" font="default" size="100%">Molecular Weight</style></keyword><keyword><style  face="normal" font="default" size="100%">Proteobacteria</style></keyword></keywords><dates><year><style  face="normal" font="default" size="100%">2000</style></year><pub-dates><date><style  face="normal" font="default" size="100%">2000 Summer</style></date></pub-dates></dates><volume><style face="normal" font="default" size="100%">1</style></volume><pages><style face="normal" font="default" size="100%">244-51</style></pages><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">Purified Ralstonia eutropha polyhydroxybutyrate (PHB) synthase from recombinant cells can exist as monomer and dimer. The polymerization reaction catalyzed by this enzyme displays a lag phase, which causes difficulties for kinetic and mechanistic characterization of the enzymatic polymerization reaction. In this study, we developed a method to eliminate the lag phase of PHB synthase by physical means, i.e., adding multihydroxyl compounds to the enzyme solution. This method allows us to recognize the nature of the lag phase as a physical rather than a chemical process. With such lag-phase-free-enzyme, the kinetic properties of the enzyme were investigated. The results indicate that 3-hydroxybutyryl-CoA (3HBCoA) is the optimal substrate for the enzyme. A slower catalytic rate and lower binding ability account for a lower reactivity of 3-hydroxyvaleryl-CoA (3HVCoA) compared to that of 3HBCoA. The change of hydroxyl group from the beta to the gamma position causes dramatic decreases in the binding ability of 4-hydroxybutyryl-CoA (4HBCoA). By using a dilution strategy and size exclusion chromatographic technique, the active form of the enzyme was identified to be the dimeric form. The number of catalytic sites in the dimeric form of the enzyme was examined by comparing the molecular weight of polyhydroxybutyrate as a function of substrate-to-enzyme ratio. The results suggest that the dimeric enzyme has only one catalytic site. A revised model of polymerization reaction catalyzed by R. eutropha PHB synthase is described.</style></abstract><issue><style face="normal" font="default" size="100%">2</style></issue><custom1><style face="normal" font="default" size="100%">http://www.ncbi.nlm.nih.gov/pubmed/11710107?dopt=Abstract</style></custom1></record><record><source-app name="Biblio" version="7.x">Drupal-Biblio</source-app><ref-type>17</ref-type><contributors><authors><author><style face="normal" font="default" size="100%">Nevin, K P</style></author><author><style face="normal" font="default" size="100%">Lovley, D R</style></author></authors></contributors><titles><title><style face="normal" font="default" size="100%">Lack of production of electron-shuttling compounds or solubilization of Fe(III) during reduction of insoluble Fe(III) oxide by Geobacter metallireducens.</style></title><secondary-title><style face="normal" font="default" size="100%">Appl Environ Microbiol</style></secondary-title><alt-title><style face="normal" font="default" size="100%">Appl. Environ. Microbiol.</style></alt-title></titles><keywords><keyword><style  face="normal" font="default" size="100%">Deltaproteobacteria</style></keyword><keyword><style  face="normal" font="default" size="100%">Electron Transport</style></keyword><keyword><style  face="normal" font="default" size="100%">Ferric Compounds</style></keyword><keyword><style  face="normal" font="default" size="100%">Iron</style></keyword><keyword><style  face="normal" font="default" size="100%">Kinetics</style></keyword><keyword><style  face="normal" font="default" size="100%">Oxidation-Reduction</style></keyword><keyword><style  face="normal" font="default" size="100%">Solubility</style></keyword></keywords><dates><year><style  face="normal" font="default" size="100%">2000</style></year><pub-dates><date><style  face="normal" font="default" size="100%">2000 May</style></date></pub-dates></dates><volume><style face="normal" font="default" size="100%">66</style></volume><pages><style face="normal" font="default" size="100%">2248-51</style></pages><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">Studies with the dissimilatory Fe(III)-reducing microorganism Geobacter metallireducens demonstrated that the common technique of separating Fe(III)-reducing microorganisms and Fe(III) oxides with semipermeable membranes in order to determine whether the Fe(III) reducers release electron-shuttling compounds and/or Fe(III) chelators is invalid. This raised doubts about the mechanisms for Fe(III) oxide reduction by this organism. However, several experimental approaches indicated that G. metallireducens does not release electron-shuttling compounds and does not significantly solubilize Fe(III) during Fe(III) oxide reduction. These results suggest that G. metallireducens directly reduces insoluble Fe(III) oxide.</style></abstract><issue><style face="normal" font="default" size="100%">5</style></issue><custom1><style face="normal" font="default" size="100%">http://www.ncbi.nlm.nih.gov/pubmed/10788411?dopt=Abstract</style></custom1></record><record><source-app name="Biblio" version="7.x">Drupal-Biblio</source-app><ref-type>17</ref-type><contributors><authors><author><style face="normal" font="default" size="100%">Quinteros, R</style></author><author><style face="normal" font="default" size="100%">Goodwin, S</style></author><author><style face="normal" font="default" size="100%">Lenz, R W</style></author><author><style face="normal" font="default" size="100%">Park, W H</style></author></authors></contributors><titles><title><style face="normal" font="default" size="100%">Extracellular degradation of medium chain length poly(beta-hydroxyalkanoates) by Comamonas sp.</style></title><secondary-title><style face="normal" font="default" size="100%">Int J Biol Macromol</style></secondary-title><alt-title><style face="normal" font="default" size="100%">Int. J. Biol. Macromol.</style></alt-title></titles><keywords><keyword><style  face="normal" font="default" size="100%">Carboxylic Ester Hydrolases</style></keyword><keyword><style  face="normal" font="default" size="100%">Gram-Negative Aerobic Rods and Cocci</style></keyword><keyword><style  face="normal" font="default" size="100%">Kinetics</style></keyword><keyword><style  face="normal" font="default" size="100%">Polyesters</style></keyword><keyword><style  face="normal" font="default" size="100%">Structure-Activity Relationship</style></keyword><keyword><style  face="normal" font="default" size="100%">Substrate Specificity</style></keyword></keywords><dates><year><style  face="normal" font="default" size="100%">1999</style></year><pub-dates><date><style  face="normal" font="default" size="100%">1999 Jun-Jul</style></date></pub-dates></dates><volume><style face="normal" font="default" size="100%">25</style></volume><pages><style face="normal" font="default" size="100%">135-43</style></pages><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">The PHA-degrading isolate, strain P37C, was enriched from residential compost for its ability to hydrolyze the medium chain length PHA, poly(beta-hydroxyoctanoate) (PHO). It was subsequently found to grow on a wide range of PHAs, including both short chain length and medium chain length PHAs. The isolate was identified as belonging to the genus Comamonas. Strain P37C formed clear zones on poly(beta-hydroxybutyrate) (PHB), (PHO) and poly(beta-hydroxyphenylvalerate) (PHPV) overlay plates. PHA clear zone tubes were prepared using seven different kinds of PHAs, ranging from PHB with four-carbon repeating units, to poly(beta-hydroxyoctanoate-co-beta-hydroxyundecanoate) (PHOU) with 8- and 11-carbon repeating units. There was a direct correlation between PHA side chain length and rate of hydrolysis of the PHAs. A series of PHOUs containing varying percentages of unsaturated bonds were used to make a series of epoxidized PHOUs (PHOEs) with varying percentages of epoxy functions. Results of clear zone tube assays showed that these functionalized PHAs were all biodegradable by strain P37C, and there was no apparent correlation between rate of biodegradation and the proportion of functional groups in the PHAs. Biodegradability of these PHAs was verified using respirometry and enzyme assays. Cell-free supernatants containing activity toward PHAs were prepared, and strain P37C was shown to synthesize at least two distinct PHA depolymerases for the hydrolysis of SCL and MCL PHAs.</style></abstract><issue><style face="normal" font="default" size="100%">1-3</style></issue><custom1><style face="normal" font="default" size="100%">http://www.ncbi.nlm.nih.gov/pubmed/10416660?dopt=Abstract</style></custom1></record><record><source-app name="Biblio" version="7.x">Drupal-Biblio</source-app><ref-type>17</ref-type><contributors><authors><author><style face="normal" font="default" size="100%">Lenz, R W</style></author><author><style face="normal" font="default" size="100%">Farcet, C</style></author><author><style face="normal" font="default" size="100%">Dijkstra, P J</style></author><author><style face="normal" font="default" size="100%">Goodwin, S</style></author><author><style face="normal" font="default" size="100%">Zhang, S</style></author></authors></contributors><titles><title><style face="normal" font="default" size="100%">Extracellular polymerization of 3-hydroxyalkanoate monomers with the polymerase of Alcaligenes eutrophus.</style></title><secondary-title><style face="normal" font="default" size="100%">Int J Biol Macromol</style></secondary-title><alt-title><style face="normal" font="default" size="100%">Int. J. Biol. Macromol.</style></alt-title></titles><keywords><keyword><style  face="normal" font="default" size="100%">Acyl Coenzyme A</style></keyword><keyword><style  face="normal" font="default" size="100%">Acyltransferases</style></keyword><keyword><style  face="normal" font="default" size="100%">Alcaligenes</style></keyword><keyword><style  face="normal" font="default" size="100%">Hydroxybutyrates</style></keyword><keyword><style  face="normal" font="default" size="100%">Kinetics</style></keyword><keyword><style  face="normal" font="default" size="100%">Polyesters</style></keyword><keyword><style  face="normal" font="default" size="100%">Substrate Specificity</style></keyword></keywords><dates><year><style  face="normal" font="default" size="100%">1999</style></year><pub-dates><date><style  face="normal" font="default" size="100%">1999 Jun-Jul</style></date></pub-dates></dates><volume><style face="normal" font="default" size="100%">25</style></volume><pages><style face="normal" font="default" size="100%">55-60</style></pages><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">Previous investigations on the role of the polymerase in the synthesis of poly-3-hydroxybutyrate (PHB) are reviewed, and the results from earlier in vitro studies on the activity and selectivity of the polymerase of Alcaligenes eutrophus are discussed. In the present study the effect of glycerol on stabilizing the polymerase after purification and on eliminating the lag phase in in vitro polymerization reactions of 3-hydroxybutyl CoA (HBCoA), and 3-hydroxyvaleryl CoA (HVCoA) are described. K(M) values were determined for the activity of the polymerase with both HBCoA and HVCoA, and the rates of propagation for both monomers were estimated. With a racemic mixture of HBCoA, the enzyme polymerized only the [R] monomer.</style></abstract><issue><style face="normal" font="default" size="100%">1-3</style></issue><custom1><style face="normal" font="default" size="100%">http://www.ncbi.nlm.nih.gov/pubmed/10416650?dopt=Abstract</style></custom1></record><record><source-app name="Biblio" version="7.x">Drupal-Biblio</source-app><ref-type>17</ref-type><contributors><authors><author><style face="normal" font="default" size="100%">Klingbeil, M M</style></author><author><style face="normal" font="default" size="100%">Walker, D J</style></author><author><style face="normal" font="default" size="100%">Arnette, R</style></author><author><style face="normal" font="default" size="100%">Sidawy, E</style></author><author><style face="normal" font="default" size="100%">Hayton, K</style></author><author><style face="normal" font="default" size="100%">Komuniecki, P R</style></author><author><style face="normal" font="default" size="100%">Komuniecki, R</style></author></authors></contributors><titles><title><style face="normal" font="default" size="100%">Identification of a novel dihydrolipoyl dehydrogenase-binding protein in the pyruvate dehydrogenase complex of the anaerobic parasitic nematode, Ascaris suum.</style></title><secondary-title><style face="normal" font="default" size="100%">J Biol Chem</style></secondary-title><alt-title><style face="normal" font="default" size="100%">J. Biol. Chem.</style></alt-title></titles><keywords><keyword><style  face="normal" font="default" size="100%">Amino Acid Sequence</style></keyword><keyword><style  face="normal" font="default" size="100%">Anaerobiosis</style></keyword><keyword><style  face="normal" font="default" size="100%">Animals</style></keyword><keyword><style  face="normal" font="default" size="100%">Ascaris suum</style></keyword><keyword><style  face="normal" font="default" size="100%">Binding Sites</style></keyword><keyword><style  face="normal" font="default" size="100%">Carrier Proteins</style></keyword><keyword><style  face="normal" font="default" size="100%">Dihydrolipoamide Dehydrogenase</style></keyword><keyword><style  face="normal" font="default" size="100%">Electrophoresis, Polyacrylamide Gel</style></keyword><keyword><style  face="normal" font="default" size="100%">Flavin-Adenine Dinucleotide</style></keyword><keyword><style  face="normal" font="default" size="100%">Helminth Proteins</style></keyword><keyword><style  face="normal" font="default" size="100%">Kinetics</style></keyword><keyword><style  face="normal" font="default" size="100%">Larva</style></keyword><keyword><style  face="normal" font="default" size="100%">Molecular Sequence Data</style></keyword><keyword><style  face="normal" font="default" size="100%">NAD</style></keyword><keyword><style  face="normal" font="default" size="100%">Oxidation-Reduction</style></keyword><keyword><style  face="normal" font="default" size="100%">Pyruvate Dehydrogenase Complex</style></keyword><keyword><style  face="normal" font="default" size="100%">Sequence Homology, Amino Acid</style></keyword></keywords><dates><year><style  face="normal" font="default" size="100%">1996</style></year><pub-dates><date><style  face="normal" font="default" size="100%">1996 Mar 8</style></date></pub-dates></dates><volume><style face="normal" font="default" size="100%">271</style></volume><pages><style face="normal" font="default" size="100%">5451-7</style></pages><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">A novel dihydrolipoyl dehydrogenase-binding protein (E3BP) which lacks an amino-terminal lipoyl domain, p45, has been identified in the pyruvate dehydrogenase complex (PDC) of the adult parasitic nematode, Ascaris suum. Sequence at the amino terminus of p45 exhibited significant similarity with internal E3-binding domains of dihydrolipoyl transacetylase (E2) and E3BP. Dissociation and resolution of a pyruvate dehydrogenase-depleted adult A. suum PDC in guanidine hydrochloride resulted in two E3-depleted E2 core preparations which were either enriched or substantially depleted of p45. Following reconstitution, the p45-enriched E2 core exhibited enhanced E3 binding, whereas, the p45-depleted E2 core exhibited dramatically reduced E3 binding. Reconstitution of either the bovine kidney or A. suum PDCs with the A. suum E3 suggested that the ascarid E3 was more sensitive to NADH inhibition when bound to the bovine kidney core. The expression of p45 was developmentally regulated and p45 was most abundant in anaerobic muscle. In contrast, E3s isolated from anaerobic muscle or aerobic second-stage larvae were identical. These results suggest that during the transition to anaerobic metabolism, E3 remains unchanged, but it appears that a novel E3BP, p45, is expressed which may help to maintain the activity of the PDC in the face of the elevated intramitochondrial NADH/NAD+ ratios associated with anaerobiosis.</style></abstract><issue><style face="normal" font="default" size="100%">10</style></issue><custom1><style face="normal" font="default" size="100%">http://www.ncbi.nlm.nih.gov/pubmed/8621401?dopt=Abstract</style></custom1></record><record><source-app name="Biblio" version="7.x">Drupal-Biblio</source-app><ref-type>17</ref-type><contributors><authors><author><style face="normal" font="default" size="100%">Lovley, D R</style></author><author><style face="normal" font="default" size="100%">Phillips, E J</style></author></authors></contributors><titles><title><style face="normal" font="default" size="100%">Reduction of uranium by Desulfovibrio desulfuricans.</style></title><secondary-title><style face="normal" font="default" size="100%">Appl Environ Microbiol</style></secondary-title><alt-title><style face="normal" font="default" size="100%">Appl. Environ. Microbiol.</style></alt-title></titles><keywords><keyword><style  face="normal" font="default" size="100%">Biodegradation, Environmental</style></keyword><keyword><style  face="normal" font="default" size="100%">Desulfovibrio</style></keyword><keyword><style  face="normal" font="default" size="100%">Kinetics</style></keyword><keyword><style  face="normal" font="default" size="100%">Oxidation-Reduction</style></keyword><keyword><style  face="normal" font="default" size="100%">Sulfates</style></keyword><keyword><style  face="normal" font="default" size="100%">Uranium</style></keyword><keyword><style  face="normal" font="default" size="100%">X-Ray Diffraction</style></keyword></keywords><dates><year><style  face="normal" font="default" size="100%">1992</style></year><pub-dates><date><style  face="normal" font="default" size="100%">1992 Mar</style></date></pub-dates></dates><volume><style face="normal" font="default" size="100%">58</style></volume><pages><style face="normal" font="default" size="100%">850-6</style></pages><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">The possibility that sulfate-reducing microorganisms contribute to U(VI) reduction in sedimentary environments was investigated. U(VI) was reduced to U(IV) when washed cells of sulfate-grown Desulfovibrio desulfuricans were suspended in a bicarbonate buffer with lactate or H2 as the electron donor. There was no U(VI) reduction in the absence of an electron donor or when the cells were killed by heat prior to the incubation. The rates of U(VI) reduction were comparable to those in respiratory Fe(III)-reducing microorganisms. Azide or prior exposure of the cells to air did not affect the ability of D. desulfuricans to reduce U(VI). Attempts to grow D. desulfuricans with U(VI) as the electron acceptor were unsuccessful. U(VI) reduction resulted in the extracellular precipitation of the U(IV) mineral uraninite. The presence of sulfate had no effect on the rate of U(VI) reduction. Sulfate and U(VI) were reduced simultaneously. Enzymatic reduction of U(VI) by D. desulfuricans was much faster than nonenzymatic reduction of U(VI) by sulfide, even when cells of D. desulfuricans were added to provide a potential catalytic surface for the nonenzymatic reaction. The results indicate that enzymatic U(VI) reduction by sulfate-reducing microorganisms may be responsible for the accumulation of U(IV) in sulfidogenic environments. Furthermore, since the reduction of U(VI) to U(IV) precipitates uranium from solution, D. desulfuricans might be a useful organism for recovering uranium from contaminated waters and waste streams.</style></abstract><issue><style face="normal" font="default" size="100%">3</style></issue><custom1><style face="normal" font="default" size="100%">http://www.ncbi.nlm.nih.gov/pubmed/1575486?dopt=Abstract</style></custom1></record><record><source-app name="Biblio" version="7.x">Drupal-Biblio</source-app><ref-type>17</ref-type><contributors><authors><author><style face="normal" font="default" size="100%">Weitzman, P D</style></author><author><style face="normal" font="default" size="100%">Danson, M J</style></author></authors></contributors><titles><title><style face="normal" font="default" size="100%">Citrate synthase.</style></title><secondary-title><style face="normal" font="default" size="100%">Curr Top Cell Regul</style></secondary-title><alt-title><style face="normal" font="default" size="100%">Curr. Top. Cell. Regul.</style></alt-title></titles><keywords><keyword><style  face="normal" font="default" size="100%">Adenosine Diphosphate</style></keyword><keyword><style  face="normal" font="default" size="100%">Adenosine Monophosphate</style></keyword><keyword><style  face="normal" font="default" size="100%">Adenosine Triphosphate</style></keyword><keyword><style  face="normal" font="default" size="100%">Amino Acids</style></keyword><keyword><style  face="normal" font="default" size="100%">Animals</style></keyword><keyword><style  face="normal" font="default" size="100%">Bacteria</style></keyword><keyword><style  face="normal" font="default" size="100%">Binding Sites</style></keyword><keyword><style  face="normal" font="default" size="100%">Cations, Divalent</style></keyword><keyword><style  face="normal" font="default" size="100%">Cations, Monovalent</style></keyword><keyword><style  face="normal" font="default" size="100%">Citrate (si)-Synthase</style></keyword><keyword><style  face="normal" font="default" size="100%">Dithionitrobenzoic Acid</style></keyword><keyword><style  face="normal" font="default" size="100%">Ketoglutaric Acids</style></keyword><keyword><style  face="normal" font="default" size="100%">Kinetics</style></keyword><keyword><style  face="normal" font="default" size="100%">Molecular Weight</style></keyword><keyword><style  face="normal" font="default" size="100%">NAD</style></keyword><keyword><style  face="normal" font="default" size="100%">NADP</style></keyword><keyword><style  face="normal" font="default" size="100%">Oxo-Acid-Lyases</style></keyword><keyword><style  face="normal" font="default" size="100%">Protein Binding</style></keyword><keyword><style  face="normal" font="default" size="100%">Species Specificity</style></keyword></keywords><dates><year><style  face="normal" font="default" size="100%">1976</style></year><pub-dates><date><style  face="normal" font="default" size="100%">1976</style></date></pub-dates></dates><volume><style face="normal" font="default" size="100%">10</style></volume><pages><style face="normal" font="default" size="100%">161-204</style></pages><language><style face="normal" font="default" size="100%">eng</style></language><custom1><style face="normal" font="default" size="100%">http://www.ncbi.nlm.nih.gov/pubmed/3389?dopt=Abstract</style></custom1></record><record><source-app name="Biblio" version="7.x">Drupal-Biblio</source-app><ref-type>17</ref-type><contributors><authors><author><style face="normal" font="default" size="100%">Rhee, S G</style></author><author><style face="normal" font="default" size="100%">Chock, P B</style></author></authors></contributors><titles><title><style face="normal" font="default" size="100%">Mechanistic studies of glutamine synthetase from Escherichia coli: kinetic evidence for two reaction intermediates in biosynthetic reaction.</style></title><secondary-title><style face="normal" font="default" size="100%">Proc Natl Acad Sci U S A</style></secondary-title><alt-title><style face="normal" font="default" size="100%">Proc. Natl. Acad. Sci. U.S.A.</style></alt-title></titles><keywords><keyword><style  face="normal" font="default" size="100%">Enzyme Activation</style></keyword><keyword><style  face="normal" font="default" size="100%">Escherichia coli</style></keyword><keyword><style  face="normal" font="default" size="100%">Glutamate-Ammonia Ligase</style></keyword><keyword><style  face="normal" font="default" size="100%">Kinetics</style></keyword><keyword><style  face="normal" font="default" size="100%">Magnesium</style></keyword></keywords><dates><year><style  face="normal" font="default" size="100%">1976</style></year><pub-dates><date><style  face="normal" font="default" size="100%">1976 Feb</style></date></pub-dates></dates><volume><style face="normal" font="default" size="100%">73</style></volume><pages><style face="normal" font="default" size="100%">476-80</style></pages><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">&lt;p&gt;Fast reaction techniques were used to study the kinetics of protein fluorescence intensity changes that are associated with the reactions of unadenylylated Escherichia coli glutamine synthetase [L-glutamate: ammonia ligase (ADP-forming), EC 6.3.1.2] with its substrates. It was established that the synthesis of glutamine occurs by a stepwise mechanism. During the catalytic process two fluorometrically distinct intermediates were observed. Both forward and reverse rate constants which lead to the formation and consumption of these intermediates were evaluated. The catalytic rate constant, kc, which was calculated from these rate constants agrees well with the values of kc which were determined by direct measurement of the overall biosynthetic activities by means of stopped-flow technique or the steady-state assay method.&lt;/p&gt;</style></abstract><issue><style face="normal" font="default" size="100%">2</style></issue><custom1><style face="normal" font="default" size="100%">http://www.ncbi.nlm.nih.gov/pubmed/1758?dopt=Abstract</style></custom1></record><record><source-app name="Biblio" version="7.x">Drupal-Biblio</source-app><ref-type>17</ref-type><contributors><authors><author><style face="normal" font="default" size="100%">Ali, S S</style></author><author><style face="normal" font="default" size="100%">Elliott, W H</style></author></authors></contributors><titles><title><style face="normal" font="default" size="100%">Bile acids. XLVII. 12alpha-Hydroxylation of precursors of allo bile acids by rabbit liver microsomes.</style></title><secondary-title><style face="normal" font="default" size="100%">Biochim Biophys Acta</style></secondary-title><alt-title><style face="normal" font="default" size="100%">Biochim. Biophys. Acta</style></alt-title></titles><keywords><keyword><style  face="normal" font="default" size="100%">Aging</style></keyword><keyword><style  face="normal" font="default" size="100%">Animals</style></keyword><keyword><style  face="normal" font="default" size="100%">Bile Acids and Salts</style></keyword><keyword><style  face="normal" font="default" size="100%">Female</style></keyword><keyword><style  face="normal" font="default" size="100%">Kinetics</style></keyword><keyword><style  face="normal" font="default" size="100%">Male</style></keyword><keyword><style  face="normal" font="default" size="100%">Microsomes, Liver</style></keyword><keyword><style  face="normal" font="default" size="100%">Mixed Function Oxygenases</style></keyword><keyword><style  face="normal" font="default" size="100%">NADP</style></keyword><keyword><style  face="normal" font="default" size="100%">Oxidation-Reduction</style></keyword><keyword><style  face="normal" font="default" size="100%">Rabbits</style></keyword><keyword><style  face="normal" font="default" size="100%">Sex Factors</style></keyword></keywords><dates><year><style  face="normal" font="default" size="100%">1975</style></year><pub-dates><date><style  face="normal" font="default" size="100%">1975 Nov 21</style></date></pub-dates></dates><volume><style face="normal" font="default" size="100%">409</style></volume><pages><style face="normal" font="default" size="100%">249-57</style></pages><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">&lt;p&gt;Rabbit liver microsomal preparations fortified with 0.1 mM NADPH effectively promote hydroxylation of [3beta-3H]- or [24-14C]allochenodeoxycholic acid or [5alpha,6alpha-3H2]5alpha-cholestane-3alpha,7alpha-diol to their respective 12alpha-hydroxyl derivatives in yields of about 25 or 65% in 60 min. Minor amounts of other products are formed from the diol. The requirements for activity of rabbit liver microsomal 12alpha-hydroxylase resemble those of rat liver microsomes. Of a number of enzyme inhibitors studied only p-chloromercuribenzoate demonstrated a marked ability to inhibit the reaction with either tritiated substrate. There was no difference in the quantity of product produced from the tritiated acid or the 14C-labeled acid. No clear sex difference was found in activity of the enzyme, nor was an appreciable difference noted in activity of the enzyme between mature and immature animals.&lt;/p&gt;</style></abstract><issue><style face="normal" font="default" size="100%">2</style></issue><custom1><style face="normal" font="default" size="100%">http://www.ncbi.nlm.nih.gov/pubmed/65?dopt=Abstract</style></custom1></record><record><source-app name="Biblio" version="7.x">Drupal-Biblio</source-app><ref-type>17</ref-type><contributors><authors><author><style face="normal" font="default" size="100%">Moroi, K</style></author><author><style face="normal" font="default" size="100%">Sato, T</style></author></authors></contributors><titles><title><style face="normal" font="default" size="100%">Comparison between procaine and isocarboxazid metabolism in vitro by a liver microsomal amidase-esterase.</style></title><secondary-title><style face="normal" font="default" size="100%">Biochem Pharmacol</style></secondary-title><alt-title><style face="normal" font="default" size="100%">Biochem. Pharmacol.</style></alt-title></titles><keywords><keyword><style  face="normal" font="default" size="100%">Amidohydrolases</style></keyword><keyword><style  face="normal" font="default" size="100%">Animals</style></keyword><keyword><style  face="normal" font="default" size="100%">Esterases</style></keyword><keyword><style  face="normal" font="default" size="100%">Hydrogen-Ion Concentration</style></keyword><keyword><style  face="normal" font="default" size="100%">In Vitro Techniques</style></keyword><keyword><style  face="normal" font="default" size="100%">Isocarboxazid</style></keyword><keyword><style  face="normal" font="default" size="100%">Kinetics</style></keyword><keyword><style  face="normal" font="default" size="100%">Male</style></keyword><keyword><style  face="normal" font="default" size="100%">Metals</style></keyword><keyword><style  face="normal" font="default" size="100%">Microsomes, Liver</style></keyword><keyword><style  face="normal" font="default" size="100%">Phospholipids</style></keyword><keyword><style  face="normal" font="default" size="100%">Procaine</style></keyword><keyword><style  face="normal" font="default" size="100%">Proteins</style></keyword><keyword><style  face="normal" font="default" size="100%">Rats</style></keyword><keyword><style  face="normal" font="default" size="100%">Subcellular Fractions</style></keyword><keyword><style  face="normal" font="default" size="100%">Temperature</style></keyword></keywords><dates><year><style  face="normal" font="default" size="100%">1975</style></year><pub-dates><date><style  face="normal" font="default" size="100%">1975 Aug 15</style></date></pub-dates></dates><volume><style face="normal" font="default" size="100%">24</style></volume><pages><style face="normal" font="default" size="100%">1517-21</style></pages><language><style face="normal" font="default" size="100%">eng</style></language><issue><style face="normal" font="default" size="100%">16</style></issue><custom1><style face="normal" font="default" size="100%">http://www.ncbi.nlm.nih.gov/pubmed/8?dopt=Abstract</style></custom1></record><record><source-app name="Biblio" version="7.x">Drupal-Biblio</source-app><ref-type>17</ref-type><contributors><authors><author><style face="normal" font="default" size="100%">Tarentino, A L</style></author><author><style face="normal" font="default" size="100%">Maley, F</style></author></authors></contributors><titles><title><style face="normal" font="default" size="100%">A comparison of the substrate specificities of endo-beta-N-acetylglucosaminidases from Streptomyces griseus and Diplococcus Pneumoniae.</style></title><secondary-title><style face="normal" font="default" size="100%">Biochem Biophys Res Commun</style></secondary-title><alt-title><style face="normal" font="default" size="100%">Biochem. Biophys. Res. Commun.</style></alt-title></titles><keywords><keyword><style  face="normal" font="default" size="100%">Acetylglucosaminidase</style></keyword><keyword><style  face="normal" font="default" size="100%">Fucose</style></keyword><keyword><style  face="normal" font="default" size="100%">Hexosaminidases</style></keyword><keyword><style  face="normal" font="default" size="100%">Kinetics</style></keyword><keyword><style  face="normal" font="default" size="100%">Oligosaccharides</style></keyword><keyword><style  face="normal" font="default" size="100%">Species Specificity</style></keyword><keyword><style  face="normal" font="default" size="100%">Streptococcus pneumoniae</style></keyword><keyword><style  face="normal" font="default" size="100%">Streptomyces griseus</style></keyword><keyword><style  face="normal" font="default" size="100%">Structure-Activity Relationship</style></keyword></keywords><dates><year><style  face="normal" font="default" size="100%">1975</style></year><pub-dates><date><style  face="normal" font="default" size="100%">1975 Nov 3</style></date></pub-dates></dates><volume><style face="normal" font="default" size="100%">67</style></volume><pages><style face="normal" font="default" size="100%">455-62</style></pages><language><style face="normal" font="default" size="100%">eng</style></language><issue><style face="normal" font="default" size="100%">1</style></issue><custom1><style face="normal" font="default" size="100%">http://www.ncbi.nlm.nih.gov/pubmed/1016?dopt=Abstract</style></custom1></record><record><source-app name="Biblio" version="7.x">Drupal-Biblio</source-app><ref-type>17</ref-type><contributors><authors><author><style face="normal" font="default" size="100%">Makar, A B</style></author><author><style face="normal" font="default" size="100%">McMartin, K E</style></author><author><style face="normal" font="default" size="100%">Palese, M</style></author><author><style face="normal" font="default" size="100%">Tephly, T R</style></author></authors></contributors><titles><title><style face="normal" font="default" size="100%">Formate assay in body fluids: application in methanol poisoning.</style></title><secondary-title><style face="normal" font="default" size="100%">Biochem Med</style></secondary-title><alt-title><style face="normal" font="default" size="100%">Biochem Med</style></alt-title></titles><keywords><keyword><style  face="normal" font="default" size="100%">Aldehyde Oxidoreductases</style></keyword><keyword><style  face="normal" font="default" size="100%">Animals</style></keyword><keyword><style  face="normal" font="default" size="100%">Body Fluids</style></keyword><keyword><style  face="normal" font="default" size="100%">Carbon Dioxide</style></keyword><keyword><style  face="normal" font="default" size="100%">Formates</style></keyword><keyword><style  face="normal" font="default" size="100%">Haplorhini</style></keyword><keyword><style  face="normal" font="default" size="100%">Humans</style></keyword><keyword><style  face="normal" font="default" size="100%">Hydrogen-Ion Concentration</style></keyword><keyword><style  face="normal" font="default" size="100%">Kinetics</style></keyword><keyword><style  face="normal" font="default" size="100%">Methanol</style></keyword><keyword><style  face="normal" font="default" size="100%">Methods</style></keyword><keyword><style  face="normal" font="default" size="100%">Pseudomonas</style></keyword></keywords><dates><year><style  face="normal" font="default" size="100%">1975</style></year><pub-dates><date><style  face="normal" font="default" size="100%">1975 Jun</style></date></pub-dates></dates><volume><style face="normal" font="default" size="100%">13</style></volume><pages><style face="normal" font="default" size="100%">117-26</style></pages><language><style face="normal" font="default" size="100%">eng</style></language><issue><style face="normal" font="default" size="100%">2</style></issue><custom1><style face="normal" font="default" size="100%">http://www.ncbi.nlm.nih.gov/pubmed/1?dopt=Abstract</style></custom1></record><record><source-app name="Biblio" version="7.x">Drupal-Biblio</source-app><ref-type>17</ref-type><contributors><authors><author><style face="normal" font="default" size="100%">Koenigs, J W</style></author></authors></contributors><titles><title><style face="normal" font="default" size="100%">Hydrogen peroxide and iron: a microbial cellulolytic system?</style></title><secondary-title><style face="normal" font="default" size="100%">Biotechnol Bioeng Symp</style></secondary-title><alt-title><style face="normal" font="default" size="100%">Biotechnol Bioeng Symp</style></alt-title></titles><keywords><keyword><style  face="normal" font="default" size="100%">Cellulase</style></keyword><keyword><style  face="normal" font="default" size="100%">Cellulose</style></keyword><keyword><style  face="normal" font="default" size="100%">Glycoside Hydrolases</style></keyword><keyword><style  face="normal" font="default" size="100%">Hydrogen Peroxide</style></keyword><keyword><style  face="normal" font="default" size="100%">Hydrogen-Ion Concentration</style></keyword><keyword><style  face="normal" font="default" size="100%">Iron</style></keyword><keyword><style  face="normal" font="default" size="100%">Kinetics</style></keyword><keyword><style  face="normal" font="default" size="100%">Mitosporic Fungi</style></keyword><keyword><style  face="normal" font="default" size="100%">Structure-Activity Relationship</style></keyword><keyword><style  face="normal" font="default" size="100%">Trichoderma</style></keyword></keywords><dates><year><style  face="normal" font="default" size="100%">1975</style></year><pub-dates><date><style  face="normal" font="default" size="100%">1975</style></date></pub-dates></dates><pages><style face="normal" font="default" size="100%">151-9</style></pages><language><style face="normal" font="default" size="100%">eng</style></language><issue><style face="normal" font="default" size="100%">5</style></issue><custom1><style face="normal" font="default" size="100%">http://www.ncbi.nlm.nih.gov/pubmed/97?dopt=Abstract</style></custom1></record><record><source-app name="Biblio" version="7.x">Drupal-Biblio</source-app><ref-type>17</ref-type><contributors><authors><author><style face="normal" font="default" size="100%">Ris, M M</style></author><author><style face="normal" font="default" size="100%">Deitrich, R A</style></author><author><style face="normal" font="default" size="100%">Von Wartburg, J P</style></author></authors></contributors><titles><title><style face="normal" font="default" size="100%">Inhibition of aldehyde reductase isoenzymes in human and rat brain.</style></title><secondary-title><style face="normal" font="default" size="100%">Biochem Pharmacol</style></secondary-title><alt-title><style face="normal" font="default" size="100%">Biochem. Pharmacol.</style></alt-title></titles><keywords><keyword><style  face="normal" font="default" size="100%">Aldehyde Oxidoreductases</style></keyword><keyword><style  face="normal" font="default" size="100%">Animals</style></keyword><keyword><style  face="normal" font="default" size="100%">Anticonvulsants</style></keyword><keyword><style  face="normal" font="default" size="100%">Barbiturates</style></keyword><keyword><style  face="normal" font="default" size="100%">Brain</style></keyword><keyword><style  face="normal" font="default" size="100%">Glutethimide</style></keyword><keyword><style  face="normal" font="default" size="100%">Humans</style></keyword><keyword><style  face="normal" font="default" size="100%">Hydantoins</style></keyword><keyword><style  face="normal" font="default" size="100%">In Vitro Techniques</style></keyword><keyword><style  face="normal" font="default" size="100%">Isoenzymes</style></keyword><keyword><style  face="normal" font="default" size="100%">Kinetics</style></keyword><keyword><style  face="normal" font="default" size="100%">NAD</style></keyword><keyword><style  face="normal" font="default" size="100%">NADP</style></keyword><keyword><style  face="normal" font="default" size="100%">Rats</style></keyword><keyword><style  face="normal" font="default" size="100%">Succinimides</style></keyword></keywords><dates><year><style  face="normal" font="default" size="100%">1975</style></year><pub-dates><date><style  face="normal" font="default" size="100%">1975 Oct 15</style></date></pub-dates></dates><volume><style face="normal" font="default" size="100%">24</style></volume><pages><style face="normal" font="default" size="100%">1865-9</style></pages><language><style face="normal" font="default" size="100%">eng</style></language><issue><style face="normal" font="default" size="100%">20</style></issue><custom1><style face="normal" font="default" size="100%">http://www.ncbi.nlm.nih.gov/pubmed/18?dopt=Abstract</style></custom1></record><record><source-app name="Biblio" version="7.x">Drupal-Biblio</source-app><ref-type>17</ref-type><contributors><authors><author><style face="normal" font="default" size="100%">Sinelnikova, E M</style></author><author><style face="normal" font="default" size="100%">Dvoretskova, T V</style></author><author><style face="normal" font="default" size="100%">Kagan, Z S</style></author></authors></contributors><titles><title><style face="normal" font="default" size="100%">[Intermediate plateaux in kinetics of the reaction catalyzed by biodegradative L-threonine dehydratase from Escherichia coli].</style></title><secondary-title><style face="normal" font="default" size="100%">Biokhimiia</style></secondary-title><alt-title><style face="normal" font="default" size="100%">Biokhimiia</style></alt-title></titles><keywords><keyword><style  face="normal" font="default" size="100%">Adenosine Monophosphate</style></keyword><keyword><style  face="normal" font="default" size="100%">Allosteric Regulation</style></keyword><keyword><style  face="normal" font="default" size="100%">Allosteric Site</style></keyword><keyword><style  face="normal" font="default" size="100%">Binding Sites</style></keyword><keyword><style  face="normal" font="default" size="100%">Escherichia coli</style></keyword><keyword><style  face="normal" font="default" size="100%">Hydro-Lyases</style></keyword><keyword><style  face="normal" font="default" size="100%">Hydrogen-Ion Concentration</style></keyword><keyword><style  face="normal" font="default" size="100%">Kinetics</style></keyword><keyword><style  face="normal" font="default" size="100%">Protein Binding</style></keyword><keyword><style  face="normal" font="default" size="100%">Threonine Dehydratase</style></keyword></keywords><dates><year><style  face="normal" font="default" size="100%">1975</style></year><pub-dates><date><style  face="normal" font="default" size="100%">1975 May-Jun</style></date></pub-dates></dates><volume><style face="normal" font="default" size="100%">40</style></volume><pages><style face="normal" font="default" size="100%">645-51</style></pages><language><style face="normal" font="default" size="100%">rus</style></language><abstract><style face="normal" font="default" size="100%">&lt;p&gt;It has been shown that for the reaction catalyzed by &quot;biodegradative&quot; L-threonine dehydratase from E. coli strains K-12 and 980 in 0.5 M phosphate-carbonate buffer, pH 8.4 and pH 9.5, the plots of initial reaction rate (v) versus the initial substrate concentration ([S]0 are characterized by several inflection points, i. e. an intermediate plateau. The plot of v versus the allosteric activator (AMP) concentration have very complicated shapes: there are several inflection points, and also the maximum at L-threonine concentration equal to 3-10(2) and 5-10(-2) M. High AMP concentrations inhibit the enzyme at high substrate concentrations. The reduced glutathion dose not influence the enzyme and does not alter the activating effect of AMP. On the basis of the data obtained it is proposed that the substrate and AMP shift the equilibrium between multiple oligomeric enzyme forms differing in catalytic activity and kinetic manifestations of allosteric interactions between the active and allosteric AMP-binding sites towards polymerization. Thus, the functioning the enzyme under study is discussed in the frames of the model of dissociating regulatory enzymes with multiple intermediate oligomeric forms.&lt;/p&gt;</style></abstract><issue><style face="normal" font="default" size="100%">3</style></issue><custom1><style face="normal" font="default" size="100%">http://www.ncbi.nlm.nih.gov/pubmed/1111?dopt=Abstract</style></custom1></record><record><source-app name="Biblio" version="7.x">Drupal-Biblio</source-app><ref-type>17</ref-type><contributors><authors><author><style face="normal" font="default" size="100%">Mier, P D</style></author><author><style face="normal" font="default" size="100%">van den Hurk, J J</style></author></authors></contributors><titles><title><style face="normal" font="default" size="100%">Lysosomal hydrolases of the epidermis. 2. Ester hydrolases.</style></title><secondary-title><style face="normal" font="default" size="100%">Br J Dermatol</style></secondary-title><alt-title><style face="normal" font="default" size="100%">Br. J. Dermatol.</style></alt-title></titles><keywords><keyword><style  face="normal" font="default" size="100%">Acid Phosphatase</style></keyword><keyword><style  face="normal" font="default" size="100%">Animals</style></keyword><keyword><style  face="normal" font="default" size="100%">Carboxylic Ester Hydrolases</style></keyword><keyword><style  face="normal" font="default" size="100%">Cerebroside-Sulfatase</style></keyword><keyword><style  face="normal" font="default" size="100%">Chondro-4-Sulfatase</style></keyword><keyword><style  face="normal" font="default" size="100%">Guinea Pigs</style></keyword><keyword><style  face="normal" font="default" size="100%">Hydrogen-Ion Concentration</style></keyword><keyword><style  face="normal" font="default" size="100%">Hydrolases</style></keyword><keyword><style  face="normal" font="default" size="100%">Kinetics</style></keyword><keyword><style  face="normal" font="default" size="100%">Lysosomes</style></keyword><keyword><style  face="normal" font="default" size="100%">Pyrophosphatases</style></keyword><keyword><style  face="normal" font="default" size="100%">Skin</style></keyword></keywords><dates><year><style  face="normal" font="default" size="100%">1975</style></year><pub-dates><date><style  face="normal" font="default" size="100%">1975 Oct</style></date></pub-dates></dates><volume><style face="normal" font="default" size="100%">93</style></volume><pages><style face="normal" font="default" size="100%">391-8</style></pages><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">&lt;p&gt;Five distinct ester hydrolases (EC 3-1) have been characterized in guinea-pig epidermis. These are carboxylic esterase, acid phosphatase, pyrophosphatase, and arylsulphatase A and B. Their properties are consistent with those of lysosomal enzymes.&lt;/p&gt;</style></abstract><issue><style face="normal" font="default" size="100%">4</style></issue><custom1><style face="normal" font="default" size="100%">http://www.ncbi.nlm.nih.gov/pubmed/31?dopt=Abstract</style></custom1></record><record><source-app name="Biblio" version="7.x">Drupal-Biblio</source-app><ref-type>17</ref-type><contributors><authors><author><style face="normal" font="default" size="100%">Mier, P D</style></author><author><style face="normal" font="default" size="100%">van den Hurk, J J</style></author></authors></contributors><titles><title><style face="normal" font="default" size="100%">Lysosomal hydrolases of the epidermis. I. Glycosidases.</style></title><secondary-title><style face="normal" font="default" size="100%">Br J Dermatol</style></secondary-title><alt-title><style face="normal" font="default" size="100%">Br. J. Dermatol.</style></alt-title></titles><keywords><keyword><style  face="normal" font="default" size="100%">Acetylglucosaminidase</style></keyword><keyword><style  face="normal" font="default" size="100%">Animals</style></keyword><keyword><style  face="normal" font="default" size="100%">Galactosidases</style></keyword><keyword><style  face="normal" font="default" size="100%">Glycoside Hydrolases</style></keyword><keyword><style  face="normal" font="default" size="100%">Guinea Pigs</style></keyword><keyword><style  face="normal" font="default" size="100%">Hydrogen-Ion Concentration</style></keyword><keyword><style  face="normal" font="default" size="100%">Kinetics</style></keyword><keyword><style  face="normal" font="default" size="100%">Lysosomes</style></keyword><keyword><style  face="normal" font="default" size="100%">Skin</style></keyword></keywords><dates><year><style  face="normal" font="default" size="100%">1975</style></year><pub-dates><date><style  face="normal" font="default" size="100%">1975 Jul</style></date></pub-dates></dates><volume><style face="normal" font="default" size="100%">93</style></volume><pages><style face="normal" font="default" size="100%">1-10</style></pages><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">&lt;p&gt;Seven distinct glycosidases (EC 3.2) have been characterized in guinea-pig epidermis. Their properties indicate them to be of lysosomal origin. The 'profile' of the epidermal glycosidases is significantly different from that reported for whole skin, the activities of beta-galactosidase and beta-acetylglucosaminidase being very high and those of the remaining enzymes relatively low in epidermis.&lt;/p&gt;</style></abstract><issue><style face="normal" font="default" size="100%">1</style></issue><custom1><style face="normal" font="default" size="100%">http://www.ncbi.nlm.nih.gov/pubmed/30?dopt=Abstract</style></custom1></record><record><source-app name="Biblio" version="7.x">Drupal-Biblio</source-app><ref-type>17</ref-type><contributors><authors><author><style face="normal" font="default" size="100%">El Halawani, M E</style></author><author><style face="normal" font="default" size="100%">Waibel, P E</style></author></authors></contributors><titles><title><style face="normal" font="default" size="100%">The relative importance of monoamine oxidase and catechol-O-methyl transferase on the physiologic response to administered norepinephrine in the turkey.</style></title><secondary-title><style face="normal" font="default" size="100%">Comp Biochem Physiol C</style></secondary-title><alt-title><style face="normal" font="default" size="100%">Comp. Biochem. Physiol. C, Comp. Pharmacol.</style></alt-title></titles><keywords><keyword><style  face="normal" font="default" size="100%">Animals</style></keyword><keyword><style  face="normal" font="default" size="100%">Blood Pressure</style></keyword><keyword><style  face="normal" font="default" size="100%">Catechol O-Methyltransferase</style></keyword><keyword><style  face="normal" font="default" size="100%">Chickens</style></keyword><keyword><style  face="normal" font="default" size="100%">Epinephrine</style></keyword><keyword><style  face="normal" font="default" size="100%">Heart</style></keyword><keyword><style  face="normal" font="default" size="100%">Kidney</style></keyword><keyword><style  face="normal" font="default" size="100%">Kinetics</style></keyword><keyword><style  face="normal" font="default" size="100%">Liver</style></keyword><keyword><style  face="normal" font="default" size="100%">Monoamine Oxidase</style></keyword><keyword><style  face="normal" font="default" size="100%">Myocardium</style></keyword><keyword><style  face="normal" font="default" size="100%">Norepinephrine</style></keyword><keyword><style  face="normal" font="default" size="100%">Organ Specificity</style></keyword><keyword><style  face="normal" font="default" size="100%">Rats</style></keyword><keyword><style  face="normal" font="default" size="100%">Species Specificity</style></keyword><keyword><style  face="normal" font="default" size="100%">Turkeys</style></keyword></keywords><dates><year><style  face="normal" font="default" size="100%">1975</style></year><pub-dates><date><style  face="normal" font="default" size="100%">1975 Oct 1</style></date></pub-dates></dates><volume><style face="normal" font="default" size="100%">52</style></volume><pages><style face="normal" font="default" size="100%">35-9</style></pages><language><style face="normal" font="default" size="100%">eng</style></language><issue><style face="normal" font="default" size="100%">1</style></issue><custom1><style face="normal" font="default" size="100%">http://www.ncbi.nlm.nih.gov/pubmed/200?dopt=Abstract</style></custom1></record></records></xml>