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[PMID]: 27770411 [Au] Autor: Minteer SD [Ad] Endereço: Departments of Chemistry and Materials Science and Engineering, University of Utah, Salt Lake City, UT, USA. minteer@chem.utah.edu. [Ti] Título: Micellar Enzymology for Thermal, pH, and Solvent Stability. [So] Source: Methods Mol Biol;1504:19-23, 2017. [Is] ISSN: 1940-6029 [Cp] País de publicação: United States [La] Idioma: eng [Ab] Resumo: This chapter describes methods for enzyme stabilization using micellar solutions. Micellar solutions have been shown to increase the thermal stability, as well as the pH and solvent tolerance of enzymes. This field is traditionally referred to as micellar enzymology. This chapter details the use of ionic and nonionic micelles for the stabilization of polyphenol oxidase, lipase, and catalase, although this method could be used with any enzymatic system or enzyme cascade system. [Mh] Termos MeSH primário: Agaricales/enzimologia Catalase/química Catecol Oxidase/química Chromobacterium/enzimologia Lipase/química Micelas [Mh] Termos MeSH secundário: Agaricales/química Animais Bovinos Chromobacterium/química Estabilidade Enzimática Concentração de Íons de Hidrogênio Cinética Lipídeos/química Fígado/enzimologia Solventes/química Tensoativos/química Temperatura Ambiente [Pt] Tipo de publicação: JOURNAL ARTICLE [Nm] Nome de substância: 0 (Lipids); 0 (Micelles); 0 (Solvents); 0 (Surface-Active Agents); EC 1.10.3.1 (Catechol Oxidase); EC 1.11.1.6 (Catalase); EC 3.1.1.3 (Lipase); EC 3.1.1.3 (lipase, Chromobacterium viscosum) [Em] Mês de entrada: 1801 [Cu] Atualização por classe: 180115 [Lr] Data última revisão: 180115 [Sb] Subgrupo de revista: IM [Da] Data de entrada para processamento: 161023 [St] Status: MEDLINE

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[PMID]: 28829025 [Au] Autor: Blackburn MB; Farrar RR; Sparks ME; Kuhar D; Mitchell A; Gundersen-Rindal DE [Ad] Endereço: Invasive Insect Biocontrol and Behavior Laboratory, USDA, ARS, Bldg 007, Rm 301, BARC-West, Beltsville, MD 20705, USA. [Ti] Título: Chromobacterium sphagni sp. nov., an insecticidal bacterium isolated from Sphagnum bogs. [So] Source: Int J Syst Evol Microbiol;67(9):3417-3422, 2017 Sep. [Is] ISSN: 1466-5034 [Cp] País de publicação: England [La] Idioma: eng [Ab] Resumo: Sixteen isolates of Gram-reaction-negative, motile, violet-pigmented bacteria were isolated from Sphagnum bogs in West Virginia and Maine, USA. 16S rRNA gene sequences and fatty acid analysis revealed a high degree of relatedness among the isolates, and genome sequencing of two isolates, IIBBL 14B-1T and IIBBL 37-2 (from West Virginia and Maine, respectively), revealed highly similar genomic sequences. The average nucleotide identity (gANI) calculated for these two isolates was found to be in excess of 99 %, but did not exceed 88 % when comparing either isolate with genomic sequences of Chromobacterium violaceum ATCC 12472T, C. haemolyticum DSM 19808T, C. piscinae ND17, C. subtsugae PRAA4-1T, C. vaccinii MWU205T or C. amazonense CBMAI 310T. Collectively, gANI and 16S rRNA gene sequence comparisons suggested that isolates IIBBL 14B-1T and IIBBL 37-2 were most closely related to C. subtsugae, but represented a distinct species. We propose the name Chromobacterium sphagni sp. nov. for this taxon; the type strain is IIBBL 14B-1T (=NRRL B-67130T=JCM 31882T). [Mh] Termos MeSH primário: Chromobacterium/classificação Filogenia Sphagnopsida/microbiologia Zonas Úmidas [Mh] Termos MeSH secundário: Técnicas de Tipagem Bacteriana Composição de Bases Chromobacterium/genética Chromobacterium/isolamento & purificação DNA Bacteriano/genética Maine RNA Ribossômico 16S/genética Análise de Sequência de DNA West Virginia [Pt] Tipo de publicação: JOURNAL ARTICLE [Nm] Nome de substância: 0 (DNA, Bacterial); 0 (RNA, Ribosomal, 16S) [Em] Mês de entrada: 1709 [Cu] Atualização por classe: 170920 [Lr] Data última revisão: 170920 [Sb] Subgrupo de revista: IM [Da] Data de entrada para processamento: 170823 [St] Status: MEDLINE [do] DOI: 10.1099/ijsem.0.002127

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[PMID]: 28685594 [Au] Autor: Patel B; Kumari S; Banerjee R; Samanta M; Das S [Ad] Endereço: a Laboratory of Environmental Microbiology and Ecology (LEnME), Department of Life Science , National Institute of Technology , Rourkela , India. [Ti] Título: Disruption of the quorum sensing regulated pathogenic traits of the biofilm-forming fish pathogen Aeromonas hydrophila by tannic acid, a potent quorum quencher. [So] Source: Biofouling;33(7):580-590, 2017 Aug. [Is] ISSN: 1029-2454 [Cp] País de publicação: England [La] Idioma: eng [Ab] Resumo: The quorum sensing (QS) phenomenon regulates a myriad of pathogenic traits in the biofilm forming fish pathogen, Aeromonas hydrophila. Blocking the QS mechanism of A. hydrophila is a novel strategy to prevent disease in fish. This study evaluated the effect of tannic acid, a QS inhibitor, on A. hydrophila-associated QS regulated phenomena. A streaking assay with Chromobacterium violaceum (CVO26) reported the presence of N-acyl homoserine lactone (AHL) in A. hydrophila, which was confirmed by HPLC and GC-MS analysis. Tannic acid-treated A. hydrophila showed a considerable reduction in violacein production, blood haemolysis activity and the pattern of swarming motility. Biofilm formation was significantly reduced (p < 0.001) (up to 95%), after tannic acid treatment for 48 h. Analysis by qRT-PCR revealed significant downregulation (p < 0.001) of AhyI and AhyR transcripts in A. hydrophila after tannic acid treatment. Co-stimulation of Catla catla with A. hydrophila and tannic acid attenuated pathogen-induced skin haemorrhages and increased the relative survival rate up to 86.6%. The study provides a mechanistic basis of tannic acid as a QS blocker and indicates its therapeutic potential against A. hydrophila-induced pathogenesis. [Mh] Termos MeSH primário: Aeromonas hydrophila/efeitos dos fármacos Biofilmes/efeitos dos fármacos Cyprinidae/microbiologia Percepção de Quorum/efeitos dos fármacos Taninos/farmacologia [Mh] Termos MeSH secundário: 4-Butirolactona/análogos & derivados 4-Butirolactona/metabolismo Aeromonas hydrophila/genética Aeromonas hydrophila/patogenicidade Aeromonas hydrophila/fisiologia Animais Proteínas de Bactérias/genética Chromobacterium/fisiologia Relação Dose-Resposta a Droga Regulação para Baixo Virulência/efeitos dos fármacos [Pt] Tipo de publicação: JOURNAL ARTICLE [Nm] Nome de substância: 0 (Bacterial Proteins); 0 (Tannins); 1192-20-7 (homoserine lactone); OL659KIY4X (4-Butyrolactone) [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: 170708 [St] Status: MEDLINE [do] DOI: 10.1080/08927014.2017.1336619

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[PMID]: 28599132 [Au] Autor: D'Almeida RE; Molina RDI; Viola CM; Luciardi MC; Nieto Peñalver C; Bardón A; Arena ME [Ad] Endereço: INBIOFAL (Instituto de Biotecnología Farmacéutica y Alimentaria), CONICET, Ayacucho 471, Tucumán 4000, Argentina. [Ti] Título: Comparison of seven structurally related coumarins on the inhibition of Quorum sensing of Pseudomonas aeruginosa and Chromobacterium violaceum. [So] Source: Bioorg Chem;73:37-42, 2017 Aug. [Is] ISSN: 1090-2120 [Cp] País de publicação: United States [La] Idioma: eng [Ab] Resumo: Quorum sensing (QS) is a cell-to-cell signaling communication system that controls the virulence behavior of a broad spectrum of bacterial pathogens, participating also in the development of biofilms, responsible of the antibiotic ineffectiveness in many infections. Therefore, QS system is an attractive target for antimicrobial therapy. In this study, we compare the effect of seven structurally related coumarins against bacterial growth, biofilm formation and elastase activity of Pseudomonas aeruginosa. In addition, the anti-pathogenic capacity of the seven coumarins was evaluated on the wild type and the biosensor strain of Chromobacterium violaceum. The comparative study of coumarins showed that molecules with hydroxyl groups on the aromatic ring displayed higher activity on the inhibition of biofilm formation of P. aeruginosa over coumarins with substituents in positions 3 and 4 or without the double 3,4-bond. These 3 or 4-hydroxylated positions caused a decrease in the anti-biofilm activity obtained for coumarin. However, the hydroxyl group in position 3 of the pyrone ring was important for the inhibition of C. violaceum QS and elastolytic activity of P. aeruginosa. The effects observed were active independently of any effect on growth. According to our results, coumarin and its hydroxylated derivatives represent an interesting group of compounds to use as anti-virulence agents against the human pathogen P. aeruginosa. [Mh] Termos MeSH primário: Antibacterianos/farmacologia Chromobacterium/efeitos dos fármacos Cumarínicos/farmacologia Pseudomonas aeruginosa/efeitos dos fármacos Percepção de Quorum/efeitos dos fármacos [Mh] Termos MeSH secundário: Antibacterianos/síntese química Antibacterianos/química Chromobacterium/química Cumarínicos/síntese química Cumarínicos/química Relação Dose-Resposta a Droga Indóis/antagonistas & inibidores Indóis/metabolismo Testes de Sensibilidade Microbiana Estrutura Molecular Relação Estrutura-Atividade [Pt] Tipo de publicação: COMPARATIVE STUDY; JOURNAL ARTICLE [Nm] Nome de substância: 0 (Anti-Bacterial Agents); 0 (Coumarins); 0 (Indoles); QJH0DSQ3SG (violacein) [Em] Mês de entrada: 1708 [Cu] Atualização por classe: 170804 [Lr] Data última revisão: 170804 [Sb] Subgrupo de revista: IM [Da] Data de entrada para processamento: 170610 [St] Status: MEDLINE

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[PMID]: 28507067 [Au] Autor: Previato-Mello M; Meireles DA; Netto LES; da Silva Neto JF [Ad] Endereço: Departamento de Biologia Celular e Molecular e Bioagentes Patogênicos, Faculdade de Medicina de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, SP, Brazil. [Ti] Título: Global Transcriptional Response to Organic Hydroperoxide and the Role of OhrR in the Control of Virulence Traits in Chromobacterium violaceum. [So] Source: Infect Immun;85(8), 2017 Aug. [Is] ISSN: 1098-5522 [Cp] País de publicação: United States [La] Idioma: eng [Ab] Resumo: A major pathway for the detoxification of organic hydroperoxides, such as cumene hydroperoxide (CHP), involves the MarR family transcriptional regulator OhrR and the peroxidase OhrA. However, the effect of these peroxides on the global transcriptome and the contribution of the OhrA/OhrR system to bacterial virulence remain poorly explored. Here, we analyzed the transcriptome profiles of exposed to CHP and after the deletion of , and we show that OhrR controls the virulence of this human opportunistic pathogen. DNA microarray and Northern blot analyses of CHP-treated cells revealed the upregulation of genes related to the detoxification of peroxides (antioxidant enzymes and thiol-reducing systems), the degradation of the aromatic moiety of CHP (oxygenases), and protection against other secondary stresses (DNA repair, heat shock, iron limitation, and nitrogen starvation responses). Furthermore, we identified two upregulated genes ( and a putative diguanylate cyclase with a GGDEF domain for cyclic di-GMP [c-di-GMP] synthesis) and three downregulated genes (hemolysin, chitinase, and collagenase) in the mutant by transcriptome analysis. Importantly, we show that OhrR directly repressed the expression of the putative diguanylate cyclase. Using a mouse infection model, we demonstrate that the mutant was attenuated for virulence and showed a decreased bacterial burden in the liver. Moreover, an -diguanylate cyclase double mutant displayed the same virulence as the wild-type strain. In conclusion, we have defined the transcriptional response to CHP, identified potential virulence factors such as diguanylate cyclase as members of the OhrR regulon, and shown that uses the transcriptional regulator OhrR to modulate its virulence. [Mh] Termos MeSH primário: Proteínas de Bactérias/metabolismo Derivados de Benzeno/metabolismo Derivados de Benzeno/farmacologia Chromobacterium/genética Chromobacterium/patogenicidade Proteínas Repressoras/metabolismo Transcrição Genética [Mh] Termos MeSH secundário: Animais Carga Bacteriana Proteínas de Bactérias/genética Quitinases/genética Colagenases/genética Proteínas de Escherichia coli/genética Perfilação da Expressão Gênica Regulação Bacteriana da Expressão Gênica Infecções por Bactérias Gram-Negativas/microbiologia Proteínas Hemolisinas Seres Humanos Peróxido de Hidrogênio Fígado/microbiologia Camundongos Oxigenases/metabolismo Peroxidases/metabolismo Fósforo-Oxigênio Liases/genética Regiões Promotoras Genéticas Proteínas Repressoras/genética Estresse Fisiológico Fatores de Transcrição/genética Fatores de Transcrição/metabolismo Virulência Fatores de Virulência/genética [Pt] Tipo de publicação: JOURNAL ARTICLE [Nm] Nome de substância: 0 (Bacterial Proteins); 0 (Benzene Derivatives); 0 (Escherichia coli Proteins); 0 (Hemolysin Proteins); 0 (Repressor Proteins); 0 (Transcription Factors); 0 (Virulence Factors); 0 (peroxide repressor proteins); BBX060AN9V (Hydrogen Peroxide); EC 1.11.1.- (Peroxidases); EC 1.13.- (Oxygenases); EC 3.2.1.14 (Chitinases); EC 3.4.24.- (Collagenases); EC 4.6.- (Phosphorus-Oxygen Lyases); EC 4.6.1.- (diguanylate cyclase); PG7JD54X4I (cumene hydroperoxide) [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

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[PMID]: 28421612 [Au] Autor: Tiwary BK; Ghosh R; Moktan S; Ranjan VK; Dey P; Choudhury D; Dutta S; Deb D; Das AP; Chakraborty R [Ad] Endereço: Omics Laboratory, Department of Biotechnology, University of North Bengal, Siliguri, India. [Ti] Título: Prospective bacterial quorum sensing inhibitors from Indian medicinal plant extracts. [So] Source: Lett Appl Microbiol;65(1):2-10, 2017 Jul. [Is] ISSN: 1472-765X [Cp] País de publicação: England [La] Idioma: eng [Ab] Resumo: As virulence of many pathogenic bacteria is regulated by the phenomenon of quorum sensing (QS), the present study aimed to find the QS-inhibiting (QS-I) property (if any) in 61 Indian medicinal plants. The presence of QS-I compound in the leaf extract was evaluated by its ability to inhibit production of pigment in Chromobacterium violaceum MTCC 2656 (violacein) and Pseudomonas aeruginosa MTCC 2297 (pyocyanin) or swarming of P. aeruginosa MTCC 2297. Extracts of three plants, Astilbe rivularis, Fragaria nubicola and Osbeckia nepalensis, have shown a dose-dependent inhibition of violacein production with no negative effect on bacterial growth. Inhibition of pyocyanin pigment production and swarming motility in P. aeruginosa MTCC 2297 was also shown. Based on the results obtained by gas chromatography-mass spectroscopy (GC-MS) and thin-layer chromatography-direct bioautography (TLC-DB), it was concluded that triterpenes and flavonoid compounds found in the three plant extracts could have QS-I activity. SIGNIFICANCE AND IMPACT OF THE STUDY: A novel alternative prospect to prevent bacterial infections without inhibiting the growth is to apply chemicals that inhibit quorum sensing mechanism of the pathogens. Antiquorum property of 61 medicinal plants was evaluated by the ability of their leaf extract(s) to inhibit production of pigment (violacein in Chromobacterium violaceum MTCC 2656, pyocyanin in Pseudomonas aeruginosa MTCC 2297) or swarming in P. aeruginosa MTCC 2297. The most prospective plants (for the development of quorum sensing inhibitor), showing inhibition of violacein production without affecting bacterial growth, were Astilbe rivularis, Fragaria nubicola and Osbeckia nepalensis. [Mh] Termos MeSH primário: Chromobacterium/efeitos dos fármacos Flavonoides/farmacologia Indóis/metabolismo Pseudomonas aeruginosa/efeitos dos fármacos Piocianina/biossíntese Percepção de Quorum/efeitos dos fármacos Triterpenos/farmacologia [Mh] Termos MeSH secundário: Antibacterianos/farmacologia Fragaria/química Medicina Tradicional Melastomataceae/química Extratos Vegetais/farmacologia Folhas de Planta/química Plantas Medicinais/química Estudos Prospectivos Saxifragaceae/química [Pt] Tipo de publicação: JOURNAL ARTICLE [Nm] Nome de substância: 0 (Anti-Bacterial Agents); 0 (Flavonoids); 0 (Indoles); 0 (Plant Extracts); 0 (Triterpenes); 9OQM399341 (Pyocyanine); QJH0DSQ3SG (violacein) [Em] Mês de entrada: 1710 [Cu] Atualização por classe: 171031 [Lr] Data última revisão: 171031 [Sb] Subgrupo de revista: IM [Da] Data de entrada para processamento: 170420 [St] Status: MEDLINE [do] DOI: 10.1111/lam.12748

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[PMID]: 28391244 [Au] Autor: Chernov KG; Neuvonen M; Brock I; Ikonen E; Verkhusha VV [Ad] Endereço: From the Department of Biochemistry and Developmental Biology and. [Ti] Título: Introducing inducible fluorescent split cholesterol oxidase to mammalian cells. [So] Source: J Biol Chem;292(21):8811-8822, 2017 May 26. [Is] ISSN: 1083-351X [Cp] País de publicação: United States [La] Idioma: eng [Ab] Resumo: Cholesterol oxidase (COase) is a bacterial enzyme catalyzing the first step in the biodegradation of cholesterol. COase is an important biotechnological tool for clinical diagnostics and production of steroid drugs and insecticides. It is also used for tracking intracellular cholesterol; however, its utility is limited by the lack of an efficient temporal control of its activity. To overcome this we have developed a regulatable fragment complementation system for COase cloned from sp. The enzyme was split into two moieties that were fused to FKBP (FK506-binding protein) and FRB (rapamycin-binding domain) pair and split GFP fragments. The addition of rapamycin reconstituted a fluorescent enzyme, termed split GFP-COase, the fluorescence level of which correlated with its oxidation activity. A rapid decrease of cellular cholesterol induced by intracellular expression of the split GFP-COase promoted the dissociation of a cholesterol biosensor D4H from the plasma membrane. The process was reversible as upon rapamycin removal, the split GFP-COase fluorescence was lost, and cellular cholesterol levels returned to normal. These data demonstrate that the split GFP-COase provides a novel tool to manipulate cholesterol in mammalian cells. [Mh] Termos MeSH primário: Proteínas de Bactérias/química Técnicas Biossensoriais/métodos Membrana Celular/química Colesterol Oxidase/química Colesterol/análise Chromobacterium/enzimologia Proteínas de Ligação a Tacrolimo/química [Mh] Termos MeSH secundário: Proteínas de Bactérias/genética Proteínas de Bactérias/metabolismo Membrana Celular/genética Membrana Celular/metabolismo Colesterol/metabolismo Colesterol Oxidase/genética Colesterol Oxidase/metabolismo Chromobacterium/genética Fluorescência Células HeLa Seres Humanos Domínios Proteicos Proteínas Recombinantes de Fusão/química Proteínas Recombinantes de Fusão/genética Proteínas Recombinantes de Fusão/metabolismo Sirolimo/química Proteínas de Ligação a Tacrolimo/genética Proteínas de Ligação a Tacrolimo/metabolismo [Pt] Tipo de publicação: JOURNAL ARTICLE [Nm] Nome de substância: 0 (Bacterial Proteins); 0 (Recombinant Fusion Proteins); 97C5T2UQ7J (Cholesterol); EC 1.1.3.6 (Cholesterol Oxidase); EC 5.2.1.- (Tacrolimus Binding Proteins); W36ZG6FT64 (Sirolimus) [Em] Mês de entrada: 1706 [Cu] Atualização por classe: 170609 [Lr] Data última revisão: 170609 [Sb] Subgrupo de revista: IM [Da] Data de entrada para processamento: 170410 [St] Status: MEDLINE [do] DOI: 10.1074/jbc.M116.761718

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[PMID]: 28294414 [Au] Autor: Musthafa KS; Sianglum W; Saising J; Lethongkam S; Voravuthikunchai SP [Ad] Endereço: Excellent Research Laboratory on Natural Products, Faculty of Science, and Natural Product Research Center of Excellence, Prince of Songkla University, Hat Yai, Songkhla, Thailand. [Ti] Título: Evaluation of phytochemicals from medicinal plants of Myrtaceae family on virulence factor production by Pseudomonas aeruginosa. [So] Source: APMIS;125(5):482-490, 2017 May. [Is] ISSN: 1600-0463 [Cp] País de publicação: Denmark [La] Idioma: eng [Ab] Resumo: Virulence factors regulated by quorum sensing (QS) play a critical role in the pathogenesis of an opportunistic human pathogen, Pseudomonas aeruginosa in causing infections to the host. Hence, in the present work, the anti-virulence potential of the medicinal plant extracts and their derived phytochemicals from Myrtaceae family was evaluated against P. aeruginosa. In the preliminary screening of the tested medicinal plant extracts, Syzygium jambos and Syzygium antisepticum demonstrated a maximum inhibition in QS-dependent violacein pigment production by Chromobacterium violaceum DMST 21761. These extracts demonstrated an inhibitory activity over a virulence factor, pyoverdin, production by P. aeruginosa ATCC 27853. Gas chromatography-mass spectrometric (GC-MS) analysis revealed the presence of 23 and 12 phytochemicals from the extracts of S. jambos and S. antisepticum respectively. Three top-ranking phytochemicals, including phytol, ethyl linoleate and methyl linolenate, selected on the basis of docking score in molecular docking studies lowered virulence factors such as pyoverdin production, protease and haemolytic activities of P. aeruginosa to a significant level. In addition, the phytochemicals reduced rhamnolipid production by the organism. The work demonstrated an importance of plant-derived compounds as anti-virulence drugs to conquer P. aeruginosa virulence towards the host. [Mh] Termos MeSH primário: Antibacterianos/farmacologia Redes e Vias Metabólicas/efeitos dos fármacos Compostos Fitoquímicos/farmacologia Extratos Vegetais/farmacologia Pseudomonas aeruginosa/efeitos dos fármacos Syzygium/química Fatores de Virulência/metabolismo [Mh] Termos MeSH secundário: Antibacterianos/isolamento & purificação Chromobacterium/efeitos dos fármacos Cromatografia Gasosa-Espectrometria de Massas Glicolipídeos/metabolismo Seres Humanos Simulação de Acoplamento Molecular Compostos Fitoquímicos/isolamento & purificação Extratos Vegetais/isolamento & purificação Plantas Medicinais/química [Pt] Tipo de publicação: JOURNAL ARTICLE [Nm] Nome de substância: 0 (Anti-Bacterial Agents); 0 (Glycolipids); 0 (Phytochemicals); 0 (Plant Extracts); 0 (Virulence Factors); 0 (rhamnolipid) [Em] Mês de entrada: 1706 [Cu] Atualização por classe: 170630 [Lr] Data última revisão: 170630 [Sb] Subgrupo de revista: IM [Da] Data de entrada para processamento: 170316 [St] Status: MEDLINE [do] DOI: 10.1111/apm.12672

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[PMID]: 28137764 [Au] Autor: Bhedi CD; Prevatte CW; Lookadoo MS; Waikel PA; Gillevet PM; Sikaroodi M; Campagna SR; Richardson LL [Ad] Endereço: Department of Biological Sciences, Florida International University, Miami, FL 33199, USA. [Ti] Título: Elevated temperature enhances short- to medium-chain acyl homoserine lactone production by black band disease-associated vibrios. [So] Source: FEMS Microbiol Ecol;93(3), 2017 Mar 01. [Is] ISSN: 1574-6941 [Cp] País de publicação: England [La] Idioma: eng [Ab] Resumo: Black band disease (BBD) of corals is a horizontally migrating, pathogenic, polymicrobial mat community which is active above a temperature threshold of 27.5°C on the reef. Bacterial isolates from BBD, the surface mucopolysaccharide layer (SML) of healthy corals and SML of healthy areas of BBD-infected corals were tested for production of short- to medium-chain acyl homoserine lactones (AHLs) using the Chromobacterium violaceum CV026 reporter strain. Of 110 bacterial isolates tested, 19 produced AHLs and 15 of these were from BBD. Eight AHLs were identified using LC-MS/MS, with 3OHC4 the most commonly produced, followed by C6. AHL-producing isolates exposed to three temperatures (24°C, 27°C, 30°C) revealed that production of three AHLs (3OHC4, 3OHC5 and 3OHC6) significantly increased at 30°C when compared to 24°C. 16S rRNA gene sequencing revealed that all of the AHL-producing BBD isolates were vibrios. Metagenomic data of BBD communities showed the presence of AHL (and autoinducer-2) genes, many of which are known to be associated with vibrios. These findings suggest that quorum sensing may be involved in BBD pathobiology and community structure due to enhanced production of quorum-sensing signal molecules (AHLs) above the temperature threshold of this globally distributed coral disease. [Mh] Termos MeSH primário: Acil-Butirolactonas/metabolismo Antozoários/microbiologia Temperatura Ambiente Vibrio/fisiologia [Mh] Termos MeSH secundário: 4-Butirolactona/análogos & derivados Animais Chromobacterium Recifes de Corais Homosserina/análogos & derivados Lactonas Percepção de Quorum RNA Ribossômico 16S/genética Espectrometria de Massas em Tandem Vibrio/genética Microbiologia da Água [Pt] Tipo de publicação: JOURNAL ARTICLE [Nm] Nome de substância: 0 (Acyl-Butyrolactones); 0 (Lactones); 0 (N-octanoylhomoserine lactone); 0 (RNA, Ribosomal, 16S); 1192-20-7 (homoserine lactone); 6KA95X0IVO (Homoserine); OL659KIY4X (4-Butyrolactone) [Em] Mês de entrada: 1708 [Cu] Atualização por classe: 170822 [Lr] Data última revisão: 170822 [Sb] Subgrupo de revista: IM [Da] Data de entrada para processamento: 170201 [St] Status: MEDLINE [do] DOI: 10.1093/femsec/fix005

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[PMID]: 28049528 [Au] Autor: Weber N; Gorwa-Grauslund M; Carlquist M [Ad] Endereço: Division of Applied Microbiology, Department of Chemistry, Faculty of Engineering, Lund University, PO Box 124, 221 00, Lund, Sweden. [Ti] Título: Improvement of whole-cell transamination with Saccharomyces cerevisiae using metabolic engineering and cell pre-adaptation. [So] Source: Microb Cell Fact;16(1):3, 2017 Jan 03. [Is] ISSN: 1475-2859 [Cp] País de publicação: England [La] Idioma: eng [Ab] Resumo: BACKGROUND: Whole-cell biocatalysis based on metabolically active baker's yeast with engineered transamination activity can be used to generate molecules carrying a chiral amine moiety. A prerequisite is though to express efficient ω-transaminases and to reach sufficient intracellular precursor levels. RESULTS: Herein, the efficiency of three different ω-transaminases originating from Capsicum chinense, Chromobacterium violaceum, and Ochrobactrum anthropi was compared for whole-cell catalyzed kinetic resolution of racemic 1-phenylethylamine to (R)-1-phenylethylamine. The gene from the most promising candidate, C. violaceum ω-transaminase (CV-TA), was expressed in a strain lacking pyruvate decarboxylase activity, which thereby accumulate the co-substrate pyruvate during glucose assimilation. However, the conversion increased only slightly under the applied reaction conditions. In parallel, the effect of increasing the intracellular pyridoxal-5'-phosphate (PLP) level by omission of thiamine during cultivation was investigated. It was found that without thiamine, PLP supplementation was redundant to keep high in vivo transamination activity. Furthermore, higher reaction rates were achieved using a strain containing several copies of CV-TA gene, highlighting the necessity to also increase the intracellular transaminase level. At last, this strain was also investigated for asymmetric whole-cell bioconversion of acetophenone to (S)-1-phenylethylamine using L-alanine as amine donor. Although functionality could be demonstrated, the activity was extremely low indicating that the native co-product removal system was unable to drive the reaction towards the amine under the applied reaction conditions. CONCLUSIONS: Altogether, our results demonstrate that (R)-1-phenylethylamine with >99% ee can be obtained via kinetic resolution at concentrations above 25 mM racemic substrate with glucose as sole co-substrate when combining appropriate genetic and process engineering approaches. Furthermore, the engineered yeast strain with highest transaminase activity was also shown to be operational as whole-cell catalyst for the production of (S)-1-phenylethylamine via asymmetric transamination of acetophenone, albeit with very low conversion. [Mh] Termos MeSH primário: Engenharia Metabólica/métodos Saccharomyces cerevisiae/enzimologia Saccharomyces cerevisiae/genética Transaminases/metabolismo [Mh] Termos MeSH secundário: Capsicum/enzimologia Capsicum/genética Chromobacterium/enzimologia Chromobacterium/genética Ochrobactrum anthropi/enzimologia Ochrobactrum anthropi/genética Fenetilaminas/metabolismo Saccharomyces cerevisiae/metabolismo Estereoisomerismo Transaminases/biossíntese Transaminases/genética [Pt] Tipo de publicação: JOURNAL ARTICLE [Nm] Nome de substância: 0 (Phenethylamines); EC 2.6.1.- (Transaminases) [Em] Mês de entrada: 1703 [Cu] Atualização por classe: 170330 [Lr] Data última revisão: 170330 [Sb] Subgrupo de revista: IM [Da] Data de entrada para processamento: 170105 [St] Status: MEDLINE [do] DOI: 10.1186/s12934-016-0615-3

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