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  1 / 2014 MEDLINE  
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[PMID]:29311556
[Au] Autor:Springsteen G; Yerabolu JR; Nelson J; Rhea CJ; Krishnamurthy R
[Ad] Endereço:Department of Chemistry, Furman University, Greenville, SC, 29613, USA.
[Ti] Título:Linked cycles of oxidative decarboxylation of glyoxylate as protometabolic analogs of the citric acid cycle.
[So] Source:Nat Commun;9(1):91, 2018 01 08.
[Is] ISSN:2041-1723
[Cp] País de publicação:England
[La] Idioma:eng
[Ab] Resumo:The development of metabolic approaches towards understanding the origins of life, which have focused mainly on the citric acid (TCA) cycle, have languished-primarily due to a lack of experimentally demonstrable and sustainable cycle(s) of reactions. We show here the existence of a protometabolic analog of the TCA involving two linked cycles, which convert glyoxylate into CO and produce aspartic acid in the presence of ammonia. The reactions proceed from either pyruvate, oxaloacetate or malonate in the presence of glyoxylate as the carbon source and hydrogen peroxide as the oxidant under neutral aqueous conditions and at mild temperatures. The reaction pathway demonstrates turnover under controlled conditions. These results indicate that simpler versions of metabolic cycles could have emerged under potential prebiotic conditions, laying the foundation for the appearance of more sophisticated metabolic pathways once control by (polymeric) catalysts became available.
[Mh] Termos MeSH primário: Dióxido de Carbono/química
Glioxilatos/química
Modelos Químicos
Origem da Vida
Ácido Oxaloacético/química
Ácido Pirúvico/química
[Mh] Termos MeSH secundário: Amônia/química
Ácido Aspártico/química
Descarboxilação
Peróxido de Hidrogênio/química
Concentração de Íons de Hidrogênio
Cinética
Malonatos/química
Redes e Vias Metabólicas
Oxirredução
[Pt] Tipo de publicação:JOURNAL ARTICLE; RESEARCH SUPPORT, NON-U.S. GOV'T; RESEARCH SUPPORT, U.S. GOV'T, NON-P.H.S.
[Nm] Nome de substância:
0 (Glyoxylates); 0 (Malonates); 142M471B3J (Carbon Dioxide); 2F399MM81J (Oxaloacetic Acid); 30KYC7MIAI (Aspartic Acid); 7664-41-7 (Ammonia); 8558G7RUTR (Pyruvic Acid); 9KX7ZMG0MK (malonic acid); BBX060AN9V (Hydrogen Peroxide); JQ39C92HH6 (glyoxylic acid)
[Em] Mês de entrada:1802
[Cu] Atualização por classe:180222
[Lr] Data última revisão:
180222
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:180110
[St] Status:MEDLINE
[do] DOI:10.1038/s41467-017-02591-0


  2 / 2014 MEDLINE  
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[PMID]:28985053
[Au] Autor:McVey AC; Medarametla P; Chee X; Bartlett S; Poso A; Spring DR; Rahman T; Welch M
[Ad] Endereço:Department of Biochemistry, University of Cambridge , Cambridge CB2 1QW, U.K.
[Ti] Título:Structural and Functional Characterization of Malate Synthase G from Opportunistic Pathogen Pseudomonas aeruginosa.
[So] Source:Biochemistry;56(41):5539-5549, 2017 Oct 17.
[Is] ISSN:1520-4995
[Cp] País de publicação:United States
[La] Idioma:eng
[Ab] Resumo:Pseudomonas aeruginosa is an opportunistic human pathogen recognized as a critical threat by the World Health Organization because of the dwindling number of effective therapies available to treat infections. Over the past decade, it has become apparent that the glyoxylate shunt plays a vital role in sustaining P. aeruginosa during infection scenarios. The glyoxylate shunt comprises two enzymes: isocitrate lyase and malate synthase isoform G. Inactivation of these enzymes has been reported to abolish the ability of P. aeruginosa to establish infection in a mammalian model system, yet we still lack the structural information to support drug design efforts. In this work, we describe the first X-ray crystal structure of P. aeruginosa malate synthase G in the apo form at 1.62 Å resolution. The enzyme is a monomer composed of four domains and is highly conserved with homologues found in other clinically relevant microorganisms. It is also dependent on Mg for catalysis. Metal ion binding led to a change in the intrinsic fluorescence of the protein, allowing us to quantitate its affinity for Mg . We also identified putative drug binding sites in malate synthase G using computational analysis and, because of the high resolution of the experimental data, were further able to characterize its hydration properties. Our data reveal two promising binding pockets in malate synthase G that may be exploited for drug design.
[Mh] Termos MeSH primário: Proteínas de Bactérias/metabolismo
Malato Sintase/metabolismo
Modelos Moleculares
Pseudomonas aeruginosa/enzimologia
[Mh] Termos MeSH secundário: Acetilcoenzima A/química
Acetilcoenzima A/metabolismo
Sequência de Aminoácidos
Apoenzimas/química
Apoenzimas/genética
Apoenzimas/metabolismo
Proteínas de Bactérias/química
Proteínas de Bactérias/genética
Sítios de Ligação
Domínio Catalítico
Biologia Computacional
Sequência Conservada
Cristalografia por Raios X
Sistemas Especialistas
Glioxilatos/química
Glioxilatos/metabolismo
Indóis/química
Indóis/metabolismo
Ligantes
Magnésio/química
Magnésio/metabolismo
Malato Sintase/química
Malato Sintase/genética
Simulação de Acoplamento Molecular
Estrutura Molecular
Conformação Proteica
Estrutura Secundária de Proteína
Proteínas Recombinantes/química
Proteínas Recombinantes/metabolismo
Alinhamento de Sequência
Homologia Estrutural de Proteína
[Pt] Tipo de publicação:COMPARATIVE STUDY; JOURNAL ARTICLE
[Nm] Nome de substância:
0 (Apoenzymes); 0 (Bacterial Proteins); 0 (Glyoxylates); 0 (Indoles); 0 (Ligands); 0 (Recombinant Proteins); 59711R38B0 (indole-3-carboxylic acid); 72-89-9 (Acetyl Coenzyme A); EC 2.3.3.9 (Malate Synthase); I38ZP9992A (Magnesium); JQ39C92HH6 (glyoxylic acid)
[Em] Mês de entrada:1710
[Cu] Atualização por classe:171116
[Lr] Data última revisão:
171116
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:171007
[St] Status:MEDLINE
[do] DOI:10.1021/acs.biochem.7b00852


  3 / 2014 MEDLINE  
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[PMID]:28658302
[Au] Autor:Campilongo R; Fung RKY; Little RH; Grenga L; Trampari E; Pepe S; Chandra G; Stevenson CEM; Roncarati D; Malone JG
[Ad] Endereço:John Innes Centre, Norwich Research Park, Colney Lane, Norwich, United Kingdom.
[Ti] Título:One ligand, two regulators and three binding sites: How KDPG controls primary carbon metabolism in Pseudomonas.
[So] Source:PLoS Genet;13(6):e1006839, 2017 Jun.
[Is] ISSN:1553-7404
[Cp] País de publicação:United States
[La] Idioma:eng
[Ab] Resumo:Effective regulation of primary carbon metabolism is critically important for bacteria to successfully adapt to different environments. We have identified an uncharacterised transcriptional regulator; RccR, that controls this process in response to carbon source availability. Disruption of rccR in the plant-associated microbe Pseudomonas fluorescens inhibits growth in defined media, and compromises its ability to colonise the wheat rhizosphere. Structurally, RccR is almost identical to the Entner-Doudoroff (ED) pathway regulator HexR, and both proteins are controlled by the same ED-intermediate; 2-keto-3-deoxy-6-phosphogluconate (KDPG). Despite these similarities, HexR and RccR control entirely different aspects of primary metabolism, with RccR regulating pyruvate metabolism (aceEF), the glyoxylate shunt (aceA, glcB, pntAA) and gluconeogenesis (pckA, gap). RccR displays complex and unusual regulatory behaviour; switching repression between the pyruvate metabolism and glyoxylate shunt/gluconeogenesis loci depending on the available carbon source. This regulatory complexity is enabled by two distinct pseudo-palindromic binding sites, differing only in the length of their linker regions, with KDPG binding increasing affinity for the 28 bp aceA binding site but decreasing affinity for the 15 bp aceE site. Thus, RccR is able to simultaneously suppress and activate gene expression in response to carbon source availability. Together, the RccR and HexR regulators enable the rapid coordination of multiple aspects of primary carbon metabolism, in response to levels of a single key intermediate.
[Mh] Termos MeSH primário: Proteínas de Bactérias/genética
Gluconatos/metabolismo
Pseudomonas fluorescens/genética
Fatores de Transcrição/genética
[Mh] Termos MeSH secundário: Sítios de Ligação
Carbono/metabolismo
Regulação Bacteriana da Expressão Gênica
Gluconeogênese/genética
Glucose/metabolismo
Glioxilatos/metabolismo
Ligantes
Redes e Vias Metabólicas/genética
Pseudomonas fluorescens/metabolismo
Ácido Pirúvico/metabolismo
[Pt] Tipo de publicação:JOURNAL ARTICLE
[Nm] Nome de substância:
0 (Bacterial Proteins); 0 (Gluconates); 0 (Glyoxylates); 0 (Ligands); 0 (Transcription Factors); 27244-54-8 (2-keto-3-deoxy-6-phosphogluconate); 7440-44-0 (Carbon); 8558G7RUTR (Pyruvic Acid); IY9XDZ35W2 (Glucose); JQ39C92HH6 (glyoxylic acid)
[Em] Mês de entrada:1707
[Cu] Atualização por classe:170726
[Lr] Data última revisão:
170726
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:170629
[St] Status:MEDLINE
[do] DOI:10.1371/journal.pgen.1006839


  4 / 2014 MEDLINE  
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[PMID]:28516845
[Au] Autor:Gründel M; Knoop H; Steuer R
[Ad] Endereço:2​Fachinstitut Theoretische Biologie (ITB), Institut für Biologie, Humboldt-Universität zu Berlin, Invalidenstraße 43, 10115 Berlin, Germany 1​Institut für Biologie, Humboldt-Universität zu Berlin, Chausseestr. 117, 10115 Berlin, Germany.
[Ti] Título:Activity and functional properties of the isocitrate lyase in the cyanobacterium Cyanothece sp. PCC 7424.
[So] Source:Microbiology;163(5):731-744, 2017 May.
[Is] ISSN:1465-2080
[Cp] País de publicação:England
[La] Idioma:eng
[Ab] Resumo:Cyanobacteria are ubiquitous photoautotrophs that assimilate atmospheric CO2 as their main source of carbon. Several cyanobacteria are known to be facultative heterotrophs that are able to grow on diverse carbon sources. For selected strains, assimilation of organic acids and mixotrophic growth on acetate has been reported for decades. However, evidence for the existence of a functional glyoxylate shunt in cyanobacteria has long been contradictory and unclear. Genes coding for isocitrate lyase (ICL) and malate synthase were recently identified in two strains of the genus Cyanothece, and the existence of the complete glyoxylate shunt was verified in a strain of Chlorogloeopsis fritschii. Here, we report that the gene PCC7424_4054 of the strain Cyanothece sp. PCC 7424 encodes an enzymatically active protein that catalyses the reaction of ICL, an enzyme that is specific for the glyoxylate shunt. We demonstrate that ICL activity is induced under alternating day/night cycles and acetate-supplemented cultures exhibit enhanced growth. In contrast, growth under constant light did not result in any detectable ICL activity or enhanced growth of acetate-supplemented cultures. Furthermore, our results indicate that, despite the presence of a glyoxylate shunt, acetate does not support continued heterotrophic growth and cell proliferation. The functional validation of the ICL is supplemented with a bioinformatics analysis of enzymes that co-occur with the glyoxylate shunt. We hypothesize that the glyoxylate shunt in Cyanothece sp. PCC 7424, and possibly other nitrogen-fixing cyanobacteria, is an adaptation to a specific ecological niche and supports assimilation of nitrogen or organic compounds during the night phase.
[Mh] Termos MeSH primário: Acetatos/metabolismo
Cyanothece/enzimologia
Cyanothece/crescimento & desenvolvimento
Glioxilatos/metabolismo
Processos Heterotróficos/genética
Isocitrato Liase/genética
[Mh] Termos MeSH secundário: Proliferação Celular/fisiologia
Cyanothece/genética
Cyanothece/metabolismo
Malato Sintase/genética
Fotoperíodo
[Pt] Tipo de publicação:JOURNAL ARTICLE
[Nm] Nome de substância:
0 (Acetates); 0 (Glyoxylates); EC 2.3.3.9 (Malate Synthase); EC 4.1.3.1 (Isocitrate Lyase); JQ39C92HH6 (glyoxylic acid)
[Em] Mês de entrada:1711
[Cu] Atualização por classe:171102
[Lr] Data última revisão:
171102
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:170519
[St] Status:MEDLINE
[do] DOI:10.1099/mic.0.000459


  5 / 2014 MEDLINE  
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[PMID]:28507068
[Au] Autor:Flynn JM; Phan C; Hunter RC
[Ad] Endereço:Department of Microbiology and Immunology, University of Minnesota, Minneapolis, Minnesota, USA.
[Ti] Título:Genome-Wide Survey of Pseudomonas aeruginosa PA14 Reveals a Role for the Glyoxylate Pathway and Extracellular Proteases in the Utilization of Mucin.
[So] Source:Infect Immun;85(8), 2017 Aug.
[Is] ISSN:1098-5522
[Cp] País de publicação:United States
[La] Idioma:eng
[Ab] Resumo:Chronic airway infections by the opportunistic pathogen are a major cause of mortality in cystic fibrosis (CF) patients. Although this bacterium has been extensively studied for its virulence determinants, biofilm growth, and immune evasion mechanisms, comparatively little is known about the nutrient sources that sustain its growth Respiratory mucins represent a potentially abundant bioavailable nutrient source, although we have recently shown that canonical pathogens inefficiently use these host glycoproteins as a growth substrate. However, given that , particularly in its biofilm mode of growth, is thought to grow slowly , the inefficient use of mucin glycoproteins may be relevant to its persistence within the CF airways. To this end, we used whole-genome fitness analysis, combining transposon mutagenesis with high-throughput sequencing, to identify genetic determinants required for growth using intact purified mucins as a sole carbon source. Our analysis reveals a biphasic growth phenotype, during which the glyoxylate pathway and amino acid biosynthetic machinery are required for mucin utilization. Secondary analyses confirmed the simultaneous liberation and consumption of acetate during mucin degradation and revealed a central role for the extracellular proteases LasB and AprA. Together, these studies describe a molecular basis for mucin-based nutrient acquisition by and reveal a host-pathogen dynamic that may contribute to its persistence within the CF airways.
[Mh] Termos MeSH primário: Glioxilatos/metabolismo
Mucinas/metabolismo
Peptídeo Hidrolases/metabolismo
Pseudomonas aeruginosa/genética
Pseudomonas aeruginosa/metabolismo
[Mh] Termos MeSH secundário: Acetatos/metabolismo
Aminoácidos/biossíntese
Proteínas de Bactérias/genética
Proteínas de Bactérias/metabolismo
Biofilmes/crescimento & desenvolvimento
Fibrose Cística/microbiologia
Elementos de DNA Transponíveis/genética
Aptidão Genética
Genoma Bacteriano
Sequenciamento de Nucleotídeos em Larga Escala
Seres Humanos
Metaloendopeptidases/genética
Metaloendopeptidases/metabolismo
Mucinas/isolamento & purificação
Mutagênese
Fenótipo
Pseudomonas aeruginosa/crescimento & desenvolvimento
[Pt] Tipo de publicação:JOURNAL ARTICLE
[Nm] Nome de substância:
0 (Acetates); 0 (Amino Acids); 0 (Bacterial Proteins); 0 (DNA Transposable Elements); 0 (Glyoxylates); 0 (Mucins); EC 3.4.- (Peptide Hydrolases); EC 3.4.24.- (Metalloendopeptidases); EC 3.4.24.26 (pseudolysin, Pseudomonas aeruginosa)
[Em] Mês de entrada:1708
[Cu] Atualização por classe:170807
[Lr] Data última revisão:
170807
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:170517
[St] Status:MEDLINE


  6 / 2014 MEDLINE  
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[PMID]:28482902
[Au] Autor:Sabra W; Bommareddy RR; Maheshwari G; Papanikolaou S; Zeng AP
[Ad] Endereço:Institute of Bioprocess and Biosystems Engineering, Hamburg University of Technology, Denickestrasse 15, 21071, Hamburg, Germany.
[Ti] Título:Substrates and oxygen dependent citric acid production by Yarrowia lipolytica: insights through transcriptome and fluxome analyses.
[So] Source:Microb Cell Fact;16(1):78, 2017 May 08.
[Is] ISSN:1475-2859
[Cp] País de publicação:England
[La] Idioma:eng
[Ab] Resumo:BACKGROUND: Unlike the well-studied backer yeast where catabolite repression represents a burden for mixed substrate fermentation, Yarrowia lipolytica, an oleaginous yeast, is recognized for its potential to produce single cell oils and citric acid from different feedstocks. These versatilities of Y. lipolytica with regards to substrate utilization make it an attractive host for biorefinery application. However, to develop a commercial process for the production of citric acid by Y. lipolytica, it is necessary to better understand the primary metabolism and its regulation, especially for growth on mixed substrate. RESULTS: Controlling the dissolved oxygen concentration (pO ) in Y. lipolytica cultures enhanced citric acid production significantly in cultures grown on glucose in mono- or dual substrate fermentations, whereas with glycerol as mono-substrate no significant effect of pO was found on citrate production. Growth on mixed substrate with glucose and glycerol revealed a relative preference of glycerol utilization by Y. lipolytica. Under optimized conditions with pO control, the citric acid titer on glucose in mono- or in dual substrate cultures was 55 and 50 g/L (with productivity of 0.6 g/L*h in both cultures), respectively, compared to a maximum of 18 g/L (0.2 g/L*h) with glycerol in monosubstrate culture. Additionally, in dual substrate fermentation, glycerol limitation was found to trigger citrate consumption despite the presence of enough glucose in pO -limited culture. The metabolic behavior of this yeast on different substrates was investigated at transcriptomic and C-based fluxomics levels. CONCLUSION: Upregulation of most of the genes of the pentose phosphate pathway was found in cultures with highest citrate production with glucose in mono- or in dual substrate fermentation with pO control. The activation of the glyoxylate cycle in the oxygen limited cultures and the imbalance caused by glycerol limitation might be the reason for the re-consumption of citrate in dual substrate fermentations. This study provides interesting targets for metabolic engineering of this industrial yeast.
[Mh] Termos MeSH primário: Ácido Cítrico/metabolismo
Oxigênio/metabolismo
Yarrowia/genética
Yarrowia/metabolismo
[Mh] Termos MeSH secundário: Citratos/metabolismo
Meios de Cultura/química
Fermentação
Perfilação da Expressão Gênica
Glucose/metabolismo
Glicerol/metabolismo
Glioxilatos/metabolismo
Análise do Fluxo Metabólico
Via de Pentose Fosfato/genética
Yarrowia/crescimento & desenvolvimento
[Pt] Tipo de publicação:JOURNAL ARTICLE
[Nm] Nome de substância:
0 (Citrates); 0 (Culture Media); 0 (Glyoxylates); 2968PHW8QP (Citric Acid); IY9XDZ35W2 (Glucose); PDC6A3C0OX (Glycerol); S88TT14065 (Oxygen)
[Em] Mês de entrada:1711
[Cu] Atualização por classe:171108
[Lr] Data última revisão:
171108
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:170510
[St] Status:MEDLINE
[do] DOI:10.1186/s12934-017-0690-0


  7 / 2014 MEDLINE  
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[PMID]:28429316
[Au] Autor:Nakazawa M
[Ad] Endereço:Faculty of Life and Environmental Sciences, Osaka Prefecture University, Sakai, Osaka, Japan. mami@biochem.osakafu-u.ac.jp.
[Ti] Título:C2 metabolism in Euglena.
[So] Source:Adv Exp Med Biol;979:39-45, 2017.
[Is] ISSN:0065-2598
[Cp] País de publicação:United States
[La] Idioma:eng
[Ab] Resumo:Euglenoids are able to assimilate fatty acids and alcohols with various carbon-chain lengths, and ethanol is known to be one of the best carbon sources to support the growth of Euglena gracilis. Ethanol is first oxidized to acetate by the sequential reactions of alcohol dehydrogenase and acetaldehyde dehydrogenase in the mitochondria, and then converted to acetyl coenzyme A (acetyl-CoA). Acetyl-CoA is metabolized through the glyoxylate cycle which is a modified tricarboxylic acid (TCA) cycle in which isocitrate lyase (ICL) and malate synthase (MS) function to bypass the two decarboxylation steps of the TCA cycle, enabling the net synthesis of carbohydrates from C2 compounds. ICL and MS form a unique bifunctional enzyme localized in Euglena mitochondria, not in glyoxysome as in other eukaryotes. The unique glyoxylate and glycolate metabolism during photorespiration is also discussed in this chapter.
[Mh] Termos MeSH primário: Ácido Acético/metabolismo
Etanol/metabolismo
Euglena/metabolismo
Glicolatos/metabolismo
Glioxilatos/metabolismo
[Mh] Termos MeSH secundário: Ciclo do Ácido Cítrico/fisiologia
Mitocôndrias/metabolismo
[Pt] Tipo de publicação:JOURNAL ARTICLE; REVIEW
[Nm] Nome de substância:
0 (Glycolates); 0 (Glyoxylates); 0WT12SX38S (glycolic acid); 3K9958V90M (Ethanol); JQ39C92HH6 (glyoxylic acid); Q40Q9N063P (Acetic Acid)
[Em] Mês de entrada:1710
[Cu] Atualização por classe:171024
[Lr] Data última revisão:
171024
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:170422
[St] Status:MEDLINE
[do] DOI:10.1007/978-3-319-54910-1_3


  8 / 2014 MEDLINE  
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[PMID]:28342313
[Au] Autor:Hubenova Y; Hubenova E; Slavcheva E; Mitov M
[Ad] Endereço:Department of Electrocatalysis and Electrocrystallization, Institute of Electrochemistry and Energy Systems "Academician Evgeni Budevski"- Bulgarian Academy of Sciences (IEES-BAS), Sofia, Bulgaria; Department of Biochemistry and Microbiology, University of Plovdiv, Plovdiv, Bulgaria. Electronic addr
[Ti] Título:The glyoxylate pathway contributes to enhanced extracellular electron transfer in yeast-based biofuel cell.
[So] Source:Bioelectrochemistry;116:10-16, 2017 Aug.
[Is] ISSN:1878-562X
[Cp] País de publicação:Netherlands
[La] Idioma:eng
[Ab] Resumo:This study provides a new insight into our understanding of yeast response to starvation conditions (sole acetate as carbon source) and applied polarization and offers important information about the role of the glyoxylate cycle in the carbohydrate synthesis and extracellular charge transfer processes in biofuel cells. The biosynthetic capabilities of yeast C. melibiosica 2491 and the up/down-regulation of the glyoxylate cycle are evaluated by modifying the cellular metabolism by feedback inhibition or carbohydrate presence and establishing the malate dehydrogenase activity and carbohydrate content together with the electric charge passed through bioelectrochemical system. 10mM malate leads to a decrease of the produced quantity of electricity with ca. 55%. At the same time, 24-times lower intracellular malate dehydrogenase activity is established. At polarization conditions the glyoxylate pathway is up-regulated and huge amount of malate is intra-converted into oxaloacetate. The yeasts are able to synthesize carbohydrates from acetate and a part of them is used for the electricity generation. It is recognized that the enhanced charge transfer in acetate fed yeast-based biofuel cell is implemented by secreted endogenous mediator and changes in the cellular surface redox activity depending on the addition of carbohydrate in the medium.
[Mh] Termos MeSH primário: Fontes de Energia Bioelétrica/microbiologia
Candida/citologia
Candida/metabolismo
Glioxilatos/metabolismo
Espaço Intracelular/metabolismo
[Mh] Termos MeSH secundário: Acetatos/farmacologia
Candida/efeitos dos fármacos
Eletroquímica
Transporte de Elétrons/efeitos dos fármacos
Espaço Intracelular/efeitos dos fármacos
[Pt] Tipo de publicação:JOURNAL ARTICLE
[Nm] Nome de substância:
0 (Acetates); 0 (Glyoxylates)
[Em] Mês de entrada:1707
[Cu] Atualização por classe:170713
[Lr] Data última revisão:
170713
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:170326
[St] Status:MEDLINE


  9 / 2014 MEDLINE  
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[PMID]:28246357
[Au] Autor:Goo E; Kang Y; Lim JY; Ham H; Hwang I
[Ad] Endereço:Department of Agricultural Biotechnology, Seoul National University, Seoul, Republic of Korea.
[Ti] Título:Lethal Consequences of Overcoming Metabolic Restrictions Imposed on a Cooperative Bacterial Population.
[So] Source:MBio;8(1), 2017 Feb 28.
[Is] ISSN:2150-7511
[Cp] País de publicação:United States
[La] Idioma:eng
[Ab] Resumo:Quorum sensing (QS) controls cooperative activities in many In some species, QS-dependent specific metabolism contributes to the stability of the cooperation. However, the mechanism by which QS and metabolic networks have coevolved to support stable public good cooperation and maintenance of the cooperative group remains unknown. Here we explored the underlying mechanisms of QS-controlled central metabolism in the evolutionary aspects of cooperation. In , the QS-dependent glyoxylate cycle plays an important role in cooperativity. A bifunctional QS-dependent transcriptional regulator, QsmR, rewired central metabolism to utilize the glyoxylate cycle rather than the tricarboxylic acid cycle. Defects in the glyoxylate cycle caused metabolic imbalance and triggered high expression of the stress-responsive chaperonin GroEL. High-level expression of GroEL in glyoxylate cycle mutants interfered with the biosynthesis of a public resource, oxalate, by physically interrupting the oxalate biosynthetic enzyme ObcA. Under such destabilized cooperativity conditions, spontaneous mutations in the gene in glyoxylate cycle mutants occurred to relieve metabolic stresses, but these mutants lost QsmR-mediated pleiotropy. Overcoming the metabolic restrictions imposed on the population of cooperators among glyoxylate cycle mutants resulted in the occurrence and selection of spontaneous mutants despite the loss of other important functions. These results provide insight into how QS bacteria have evolved to maintain stable cooperation via QS-mediated metabolic coordination. We address how quorum sensing (QS) has coevolved with metabolic networks to maintain bacterial sociality. We found that QS-mediated metabolic rewiring is critical for sustainable bacterial cooperation in The loss of the glyoxylate cycle triggered the expression of the stress-responsive molecular chaperonin GroEL. Excessive biosynthesis of GroEL physically hampered biosynthesis of a public good, oxalate. This is one good example of how molecular chaperones play critical roles in bacterial cooperation. In addition, we showed that metabolic restrictions in the glyoxylate cycle acted as a selection pressure on metabolic networks; there were spontaneous mutations in the gene to relieve such stresses. However, the presence of spontaneous mutants had tragic consequences for a cooperative population of due to failure of -dependent activation of public good biosynthesis. These results provide a good example of a bacterial strategy for robust cooperation via QS-mediated metabolic rewiring.
[Mh] Termos MeSH primário: Burkholderia/fisiologia
Regulação Bacteriana da Expressão Gênica
Glioxilatos/metabolismo
Redes e Vias Metabólicas/genética
Percepção de Quorum
[Mh] Termos MeSH secundário: Evolução Biológica
Burkholderia/crescimento & desenvolvimento
Burkholderia/metabolismo
Redes Reguladoras de Genes
[Pt] Tipo de publicação:JOURNAL ARTICLE
[Nm] Nome de substância:
0 (Glyoxylates); JQ39C92HH6 (glyoxylic acid)
[Em] Mês de entrada:1706
[Cu] Atualização por classe:170628
[Lr] Data última revisão:
170628
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:170302
[St] Status:MEDLINE


  10 / 2014 MEDLINE  
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[PMID]:28214445
[Au] Autor:Guerrero C; Vera C; Serna N; Illanes A
[Ad] Endereço:School of Biochemical Engineering, Pontificia Universidad Católica de Valparaíso (PUCV), Valparaíso, Chile. Electronic address: c.siancas@gmail.com.
[Ti] Título:Immobilization of Aspergillus oryzae ß-galactosidase in an agarose matrix functionalized by four different methods and application to the synthesis of lactulose.
[So] Source:Bioresour Technol;232:53-63, 2017 May.
[Is] ISSN:1873-2976
[Cp] País de publicação:England
[La] Idioma:eng
[Ab] Resumo:Aspergillus oryzae ß-galactosidase was immobilized in monofunctional glyoxyl-agarose and heterofunctional supports (amino-glyoxyl, carboxy-glyoxyl and chelate-glyoxyl agarose), for obtaining highly active and stable catalysts for lactulose synthesis. Specific activities of the amino-glyoxyl agarose, carboxy-glyoxyl agarose and chelate-glyoxyl agarose derivatives were 3676, 430 and 454IU/g biocatalyst with half-life values at 50°C of 247, 100 and 100h respectively. Specific activities of 3490, 2559 and 1060IU/g were obtained for fine, standard and macro agarose respectively. High immobilization yield (39.4%) and specific activity of 7700IU/g was obtained with amino-glyoxyl-agarose as support. The highest yields of lactulose synthesis were obtained with monofunctional glyoxyl-agarose. Selectivity of lactulose synthesis was influenced by the support functionalization: glyoxyl-agarose and amino-glyoxyl-agarose derivatives retained the selectivity of the free enzyme, while selectivity with the carboxy-glyoxyl-agarose and chelate-glyoxyl-agarose derivatives was reduced, favoring the synthesis of transgalactosylated oligosaccharides over lactulose.
[Mh] Termos MeSH primário: Aspergillus oryzae/enzimologia
Biotecnologia/métodos
Enzimas Imobilizadas/metabolismo
Lactulose/biossíntese
Sefarose/farmacologia
beta-Galactosidase/metabolismo
[Mh] Termos MeSH secundário: Estabilidade Enzimática/efeitos dos fármacos
Glicosilação/efeitos dos fármacos
Glioxilatos/farmacologia
Tamanho da Partícula
Temperatura Ambiente
[Pt] Tipo de publicação:JOURNAL ARTICLE
[Nm] Nome de substância:
0 (Enzymes, Immobilized); 0 (Glyoxylates); 105054-62-4 (glyoxyl agarose); 4618-18-2 (Lactulose); 9012-36-6 (Sepharose); EC 3.2.1.23 (beta-Galactosidase)
[Em] Mês de entrada:1705
[Cu] Atualização por classe:170515
[Lr] Data última revisão:
170515
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:170219
[St] Status:MEDLINE



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