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Pesquisa : D12.776.097 [Categoria DeCS]
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  1 / 160240 MEDLINE  
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[PMID]:29484749
[Au] Autor:Khosravi AD; Meghdadi H; Ghadiri AA; Alami A; Sina AH; Mirsaeidi M
[Ad] Endereço:Infectious and Tropical Diseases Research Center, Health Research Institute, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran.
[Ti] Título:rpoB gene mutations among Mycobacterium tuberculosis isolates from extrapulmonary sites.
[So] Source:APMIS;126(3):241-247, 2018 Mar.
[Is] ISSN:1600-0463
[Cp] País de publicação:Denmark
[La] Idioma:eng
[Ab] Resumo:The aim of this study was to analyze mutations occurring in the rpoB gene of Mycobacterium tuberculosis (MTB) isolates from clinical samples of extrapulmonary tuberculosis (EPTB). Seventy formalin-fixed, paraffin-embedded samples and fresh tissue samples from confirmed EPTB cases were analyzed. Nested PCR based on the rpoB gene was performed on the extracted DNAs, combined with cloning and subsequent sequencing. Sixty-seven (95.7%) samples were positive for nester PCR. Sequence analysis of the 81 bp region of the rpoB gene demonstrated mutations in 41 (61.2%) of 67 sequenced samples. Several point mutations including deletion mutations at codons 510, 512, 513 and 515, with 45% and 51% of the mutations in codons 512 and 513 respectively were seen, along with 26% replacement mutations at codons 509, 513, 514, 518, 520, 524 and 531. The most common alteration was Gln → His, at codon 513, presented in 30 (75.6%) isolates. This study demonstrated sequence alterations in codon 513 of the 81 bp region of the rpoB gene as the most common mutation occurred in 75.6% of molecularly confirmed rifampin-resistant strains. In addition, simultaneous mutation at codons 512 and 513 was demonstrated in 34.3% of the isolates.
[Mh] Termos MeSH primário: Antibióticos Antituberculose/farmacologia
Proteínas de Bactérias/genética
RNA Polimerases Dirigidas por DNA/genética
Farmacorresistência Bacteriana/genética
Mycobacterium tuberculosis/genética
Rifampina/farmacologia
Tuberculose/microbiologia
[Mh] Termos MeSH secundário: Adulto
Idoso
Idoso de 80 Anos ou mais
Células Cultivadas
Feminino
Seres Humanos
Masculino
Testes de Sensibilidade Microbiana
Meia-Idade
Mycobacterium tuberculosis/efeitos dos fármacos
Mycobacterium tuberculosis/isolamento & purificação
Mutação Puntual/genética
Deleção de Sequência/genética
Adulto Jovem
[Pt] Tipo de publicação:JOURNAL ARTICLE
[Nm] Nome de substância:
0 (Antibiotics, Antitubercular); 0 (Bacterial Proteins); 0 (rpoB protein, Mycobacterium tuberculosis); EC 2.7.7.6 (DNA-Directed RNA Polymerases); VJT6J7R4TR (Rifampin)
[Em] Mês de entrada:1803
[Cu] Atualização por classe:180309
[Lr] Data última revisão:
180309
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:180228
[St] Status:MEDLINE
[do] DOI:10.1111/apm.12804


  2 / 160240 MEDLINE  
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[PMID]:29399876
[Au] Autor:Martínez-García S; Rodríguez-Martínez S; Cancino-Diaz ME; Cancino-Diaz JC
[Ad] Endereço:Departamento de Microbiología, Escuela Nacional de Ciencias Biológicas, Instituto Politécnico Nacional, Ciudad de México, Mexico.
[Ti] Título:Extracellular proteases of Staphylococcus epidermidis: roles as virulence factors and their participation in biofilm.
[So] Source:APMIS;126(3):177-185, 2018 Mar.
[Is] ISSN:1600-0463
[Cp] País de publicação:Denmark
[La] Idioma:eng
[Ab] Resumo:Staphylococci produce a large number of extracellular proteases, some of which are considered as potential virulence factors. Staphylococcus epidermidis is a causative agent of nosocomial infections in medical devices by the formation of biofilms. It has been proposed that proteases contribute to the different stages of biofilm formation. S. epidermidis secretes a small number of extracellular proteases, such as serine protease Esp, cysteine protease EcpA, and metalloprotease SepA that have a relatively low substrate specificity. Recent findings indicate a significant contribution of extracellular proteases in biofilm formation through the proteolytic inactivation of adhesion molecules. The objective of this work is to provide an overview of the current knowledge of S. epidermidis' extracellular proteases during pathogenicity, especially in the different stages of biofilm formation.
[Mh] Termos MeSH primário: Proteínas de Bactérias/metabolismo
Biofilmes/crescimento & desenvolvimento
Cisteína Proteases/metabolismo
Metaloendopeptidases/metabolismo
Serina Proteases/metabolismo
Staphylococcus epidermidis/enzimologia
[Mh] Termos MeSH secundário: Moléculas de Adesão Celular/metabolismo
Infecção Hospitalar/microbiologia
Infecção Hospitalar/patologia
Seres Humanos
Infecções Estafilocócicas/microbiologia
Infecções Estafilocócicas/patologia
Staphylococcus epidermidis/metabolismo
Staphylococcus epidermidis/patogenicidade
Fatores de Virulência/metabolismo
[Pt] Tipo de publicação:JOURNAL ARTICLE; REVIEW
[Nm] Nome de substância:
0 (Bacterial Proteins); 0 (Cell Adhesion Molecules); 0 (Virulence Factors); EC 3.4.- (Cysteine Proteases); EC 3.4.- (Serine Proteases); EC 3.4.24.- (Metalloendopeptidases); EC 3.4.24.- (SepA protein, Staphylococcus epidermidis)
[Em] Mês de entrada:1803
[Cu] Atualização por classe:180309
[Lr] Data última revisão:
180309
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:180206
[St] Status:MEDLINE
[do] DOI:10.1111/apm.12805


  3 / 160240 MEDLINE  
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[PMID]:29391275
[Au] Autor:Yang X; Wang J; Bing G; Bie P; De Y; Lyu Y; Wu Q
[Ad] Endereço:Key Laboratory of Animal Epidemiology and Zoonosis of the Ministry of Agriculture, College of Veterinary Medicine, China Agricultural University, Beijing 100193, China.
[Ti] Título:Ortholog-based screening and identification of genes related to intracellular survival.
[So] Source:Gene;651:134-142, 2018 Apr 20.
[Is] ISSN:1879-0038
[Cp] País de publicação:Netherlands
[La] Idioma:eng
[Ab] Resumo:Bioinformatics and comparative genomics analysis methods were used to predict unknown pathogen genes based on homology with identified or functionally clustered genes. In this study, the genes of common pathogens were analyzed to screen and identify genes associated with intracellular survival through sequence similarity, phylogenetic tree analysis and the λ-Red recombination system test method. The total 38,952 protein-coding genes of common pathogens were divided into 19,775 clusters. As demonstrated through a COG analysis, information storage and processing genes might play an important role intracellular survival. Only 19 clusters were present in facultative intracellular pathogens, and not all were present in extracellular pathogens. Construction of a phylogenetic tree selected 18 of these 19 clusters. Comparisons with the DEG database and previous research revealed that seven other clusters are considered essential gene clusters and that seven other clusters are associated with intracellular survival. Moreover, this study confirmed that clusters screened by orthologs with similar function could be replaced with an approved uvrY gene and its orthologs, and the results revealed that the usg gene is associated with intracellular survival. The study improves the current understanding of intracellular pathogens characteristics and allows further exploration of the intracellular survival-related gene modules in these pathogens.
[Mh] Termos MeSH primário: Bactérias/genética
Fenômenos Fisiológicos Bacterianos
Células/microbiologia
Genes Bacterianos
[Mh] Termos MeSH secundário: Animais
Proteínas de Bactérias/genética
Proteínas de Bactérias/fisiologia
Células Cultivadas
Genes Essenciais
Interações Hospedeiro-Patógeno
Camundongos
Família Multigênica
Filogenia
[Pt] Tipo de publicação:JOURNAL ARTICLE
[Nm] Nome de substância:
0 (Bacterial Proteins)
[Em] Mês de entrada:1803
[Cu] Atualização por classe:180309
[Lr] Data última revisão:
180309
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:180203
[St] Status:MEDLINE


  4 / 160240 MEDLINE  
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[PMID]:29367487
[Au] Autor:Lin Y; Xie X; Yuan B; Fu J; Liu L; Tian H; Chen T; He D
[Ad] Endereço:College of Food Science and Engineering, Wuhan polytechnic University.
[Ti] Título:Optimization of Enzymatic Cell Disruption for Improving Lipid Extraction from Schizochytrium sp. through Response Surface Methodology.
[So] Source:J Oleo Sci;67(2):215-224, 2018 Feb 01.
[Is] ISSN:1347-3352
[Cp] País de publicação:Japan
[La] Idioma:eng
[Ab] Resumo:This study is aimed to explore the optimal conditions of cell disruption in the extraction algae oil process, using alkaline protease to disrupt cell of Schizochytrium sp. to extract oil in this paper. The effects of enzymatic lysis temperature, enzymatic lysis time, enzyme dosage and pH value on oil yield and DHA yield were studied. Through the combination of single factor test and response surface design, the optimal cell disruption conditions were screened out. The fatty acid composition of algal oil was analyzed by gas chromatography-massspectrometry (GC-MS). The results showed that when the conditions were: enzymatic lysis temperature 55°C, enzymatic lysis time 9 h, enzyme dosage 3% of biomass and pH 8,oil yield and DHA yield reached the highest 14.52 g/L and 7.12 g/L, respectively. When the strains were cultured in 50 L fermentor, oil yield reached 26.27 g/L and DHA yield reached 12.89 g/L. They were 1.81 times higher than that in shake-flask cultivation. The optimization experiment provides the basis for the industrial production of Schizochytrium sp.
[Mh] Termos MeSH primário: Proteínas de Bactérias
Endopeptidases
Extração Líquido-Líquido/métodos
Óleos/isolamento & purificação
Estramenópilas/química
[Mh] Termos MeSH secundário: Ácidos Graxos/análise
Cromatografia Gasosa-Espectrometria de Massas
Concentração de Íons de Hidrogênio
Óleos/química
Estramenópilas/citologia
Temperatura Ambiente
Fatores de Tempo
[Pt] Tipo de publicação:JOURNAL ARTICLE
[Nm] Nome de substância:
0 (Bacterial Proteins); 0 (Fatty Acids); 0 (Oils); EC 3.4.- (Endopeptidases); EC 3.4.99.- (alkaline protease)
[Em] Mês de entrada:1803
[Cu] Atualização por classe:180309
[Lr] Data última revisão:
180309
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:180126
[St] Status:MEDLINE
[do] DOI:10.5650/jos.ess17166


  5 / 160240 MEDLINE  
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[PMID]:29066393
[Au] Autor:Badshah SL; Sun J; Mula S; Gorka M; Baker P; Luthra R; Lin S; van der Est A; Golbeck JH; Redding KE
[Ad] Endereço:School of Molecular Sciences, Arizona State University, Tempe, AZ 85287, USA.
[Ti] Título:Mutations in algal and cyanobacterial Photosystem I that independently affect the yield of initial charge separation in the two electron transfer cofactor branches.
[So] Source:Biochim Biophys Acta;1859(1):42-55, 2018 01.
[Is] ISSN:0006-3002
[Cp] País de publicação:Netherlands
[La] Idioma:eng
[Ab] Resumo:In Photosystem I, light-induced electron transfer can occur in either of two symmetry-related branches of cofactors, each of which is composed of a pair of chlorophylls (ec2 /ec3 or ec2 /ec3 ) and a phylloquinone (PhQ or PhQ ). The axial ligand to the central Mg of the ec2 and ec2 chlorophylls is a water molecule that is also H-bonded to a nearby Asn residue. Here, we investigate the importance of this interaction for charge separation by converting each of the Asn residues to a Leu in the green alga, Chlamydomonas reinhardtii, and the cyanobacterium, Synechocystis sp. PCC6803, and studying the energy and electron transfer using time-resolved optical and EPR spectroscopy. Nanosecond transient absorbance measurements of the PhQ to F electron transfer show that in both species, the PsaA-N604L mutation (near ec2 ) results in a ~50% reduction in the amount of electron transfer in the B-branch, while the PsaB-N591L mutation (near ec2 ) results in a ~70% reduction in the amount of electron transfer in the A-branch. A diminished quantum yield of P PhQ is also observed in ultrafast optical experiments, but the lower yield does not appear to be a consequence of charge recombination in the nanosecond or microsecond timescales. The most significant finding is that the yield of electron transfer in the unaffected branch did not increase to compensate for the lower yield in the affected branch. Hence, each branch of the reaction center appears to operate independently of the other in carrying out light-induced charge separation.
[Mh] Termos MeSH primário: Proteínas de Bactérias/química
Chlamydomonas reinhardtii/enzimologia
Mutação de Sentido Incorreto
Complexo de Proteína do Fotossistema I/química
Complexo de Proteína do Fotossistema I/genética
Synechocystis/enzimologia
[Mh] Termos MeSH secundário: Substituição de Aminoácidos
Proteínas de Bactérias/genética
Proteínas de Bactérias/metabolismo
Chlamydomonas reinhardtii/genética
Transporte de Elétrons
Complexo de Proteína do Fotossistema I/metabolismo
Synechocystis/genética
[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 (Bacterial Proteins); 0 (Photosystem I Protein Complex)
[Em] Mês de entrada:1803
[Cu] Atualização por classe:180309
[Lr] Data última revisão:
180309
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:171026
[St] Status:MEDLINE


  6 / 160240 MEDLINE  
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[PMID]:29051067
[Au] Autor:Wang Y; Ryu BH; Yoo W; Lee CW; Kim KK; Lee JH; Kim TD
[Ad] Endereço:Department of Chemistry, College of Natural Science, Sookmyung Women's University, Seoul 04310, Republic of Korea.
[Ti] Título:Identification, characterization, immobilization, and mutational analysis of a novel acetylesterase with industrial potential (LaAcE) from Lactobacillus acidophilus.
[So] Source:Biochim Biophys Acta;1862(1):197-210, 2018 01.
[Is] ISSN:0006-3002
[Cp] País de publicação:Netherlands
[La] Idioma:eng
[Ab] Resumo:Lactic acid bacteria, which are involved in the fermentation of vegetables, meats, and dairy products, are widely used for the productions of small organic molecules and bioactive peptides. Here, a novel acetylesterase (LaAcE) from Lactobacillus acidophilus NCFM was identified, functionally characterized, immobilized, and subjected to site-directed mutagenesis for biotechnological applications. The enzymatic properties of LaAcE were investigated using biochemical and biophysical methods including native polyacrylamide gel electrophoresis, acetic acid release, biochemical assays, enzyme kinetics, and spectroscopic methods. Interestingly, LaAcE exhibited the ability to act on a broad range of substrates including glucose pentaacetate, glyceryl tributyrate, fish oil, and fermentation-related compounds. Furthermore, immobilization of LaAcE showed good recycling ability and high thermal stability compared with free LaAcE. A structural model of LaAcE was used to guide mutational analysis of hydrophobic substrate-binding region, which was composed of Leu , Phe , and Val . Five mutants (L156A, F164A, V204A, L156A/F164A, and L156A/V204A) were generated and investigated to elucidate the roles of these hydrophobic residues in substrate specificity. This work provided valuable insights into the properties of LaAcE, and demonstrated that LaAcE could be used as a model enzyme of acetylesterase in lactic acid bacteria, making LaAcE a great candidate for industrial applications.
[Mh] Termos MeSH primário: Acetilesterase
Proteínas de Bactérias
Enzimas Imobilizadas
Lactobacillus acidophilus
Modelos Moleculares
Mutação de Sentido Incorreto
[Mh] Termos MeSH secundário: Acetilesterase/química
Acetilesterase/genética
Substituição de Aminoácidos
Proteínas de Bactérias/química
Proteínas de Bactérias/genética
Enzimas Imobilizadas/química
Enzimas Imobilizadas/genética
Lactobacillus acidophilus/enzimologia
Lactobacillus acidophilus/genética
Especificidade por Substrato/genética
[Pt] Tipo de publicação:JOURNAL ARTICLE; RESEARCH SUPPORT, NON-U.S. GOV'T
[Nm] Nome de substância:
0 (Bacterial Proteins); 0 (Enzymes, Immobilized); EC 3.1.1.6 (Acetylesterase)
[Em] Mês de entrada:1803
[Cu] Atualização por classe:180309
[Lr] Data última revisão:
180309
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:171021
[St] Status:MEDLINE


  7 / 160240 MEDLINE  
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[PMID]:28986298
[Au] Autor:Hsiao JC; McGrath AP; Kielmann L; Kalimuthu P; Darain F; Bernhardt PV; Harmer J; Lee M; Meyers K; Maher MJ; Kappler U
[Ad] Endereço:Centre for Metals in Biology, School of Chemistry and Molecular Biosciences, University of Queensland, St Lucia, QLD 4072, Australia.
[Ti] Título:The central active site arginine in sulfite oxidizing enzymes alters kinetic properties by controlling electron transfer and redox interactions.
[So] Source:Biochim Biophys Acta;1859(1):19-27, 2018 01.
[Is] ISSN:0006-3002
[Cp] País de publicação:Netherlands
[La] Idioma:eng
[Ab] Resumo:A central conserved arginine, first identified as a clinical mutation leading to sulfite oxidase deficiency, is essential for catalytic competency of sulfite oxidizing molybdoenzymes, but the molecular basis for its effects on turnover and substrate affinity have not been fully elucidated. We have used a bacterial sulfite dehydrogenase, SorT, which lacks an internal heme group, but transfers electrons to an external, electron accepting cytochrome, SorU, to investigate the molecular functions of this arginine residue (Arg78). Assay of the SorT Mo centre catalytic competency in the absence of SorU showed that substitutions in the central arginine (R78Q, R78K and R78M mutations) only moderately altered SorT catalytic properties, except for R78M which caused significant reduction in SorT activity. The substitutions also altered the Mo-centre redox potentials (Mo potential lowered by ca. 60-80mV). However, all Arg78 mutations significantly impaired the ability of SorT to transfer electrons to SorU, where activities were reduced 17 to 46-fold compared to SorT , precluding determination of kinetic parameters. This was accompanied by the observation of conformational changes in both the introduced Gln and Lys residues in the crystal structure of the enzymes. Taking into account data collected by others on related SOE mutations we propose that the formation and maintenance of an electron transfer complex between the Mo centre and electron accepting heme groups is the main function of the central arginine, and that the reduced turnover and increases in K are caused by the inefficient operation of the oxidative half reaction of the catalytic cycle in enzymes carrying these mutations.
[Mh] Termos MeSH primário: Arginina/química
Proteínas de Bactérias/química
Sinorhizobium meliloti/enzimologia
Sulfito Desidrogenase/química
[Mh] Termos MeSH secundário: Substituição de Aminoácidos
Arginina/metabolismo
Proteínas de Bactérias/genética
Proteínas de Bactérias/metabolismo
Domínio Catalítico
Transporte de Elétrons
Cinética
Molibdênio
Mutação de Sentido Incorreto
Oxirredução
Sinorhizobium meliloti/genética
Sulfito Desidrogenase/genética
Sulfito Desidrogenase/metabolismo
[Pt] Tipo de publicação:JOURNAL ARTICLE; RESEARCH SUPPORT, NON-U.S. GOV'T
[Nm] Nome de substância:
0 (Bacterial Proteins); 81AH48963U (Molybdenum); 94ZLA3W45F (Arginine); EC 1.8.2.1 (Sulfite Dehydrogenase)
[Em] Mês de entrada:1803
[Cu] Atualização por classe:180309
[Lr] Data última revisão:
180309
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:171008
[St] Status:MEDLINE


  8 / 160240 MEDLINE  
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[PMID]:28970007
[Au] Autor:Preissler J; Wahlefeld S; Lorent C; Teutloff C; Horch M; Lauterbach L; Cramer SP; Zebger I; Lenz O
[Ad] Endereço:Technische Universität Berlin, Institut für Chemie, Sekr. PC14, Straße des 17. Juni 135, D-10623 Berlin, Germany.
[Ti] Título:Enzymatic and spectroscopic properties of a thermostable [NiFe]­hydrogenase performing H -driven NAD -reduction in the presence of O .
[So] Source:Biochim Biophys Acta;1859(1):8-18, 2018 01.
[Is] ISSN:0006-3002
[Cp] País de publicação:Netherlands
[La] Idioma:eng
[Ab] Resumo:Biocatalysts that mediate the H -dependent reduction of NAD to NADH are attractive from both a fundamental and applied perspective. Here we present the first biochemical and spectroscopic characterization of an NAD -reducing [NiFe]­hydrogenase that sustains catalytic activity at high temperatures and in the presence of O , which usually acts as an inhibitor. We isolated and sequenced the four structural genes, hoxFUYH, encoding the soluble NAD -reducing [NiFe]­hydrogenase (SH) from the thermophilic betaproteobacterium, Hydrogenophilus thermoluteolus TH-1 (Ht). The HtSH was recombinantly overproduced in a hydrogenase-free mutant of the well-studied, H -oxidizing betaproteobacterium Ralstonia eutropha H16 (Re). The enzyme was purified and characterized with various biochemical and spectroscopic techniques. Highest H -mediated NAD reduction activity was observed at 80°C and pH6.5, and catalytic activity was found to be sustained at low O concentrations. Infrared spectroscopic analyses revealed a spectral pattern for as-isolated HtSH that is remarkably different from those of the closely related ReSH and other [NiFe]­hydrogenases. This indicates an unusual configuration of the oxidized catalytic center in HtSH. Complementary electron paramagnetic resonance spectroscopic analyses revealed spectral signatures similar to related NAD -reducing [NiFe]­hydrogenases. This study lays the groundwork for structural and functional analyses of the HtSH as well as application of this enzyme for H -driven cofactor recycling under oxic conditions at elevated temperatures.
[Mh] Termos MeSH primário: Proteínas de Bactérias/química
Cupriavidus necator/enzimologia
Temperatura Alta
Hidrogênio/química
Hidrogenase/química
Hydrogenophilaceae/enzimologia
NAD/química
[Mh] Termos MeSH secundário: Proteínas de Bactérias/genética
Proteínas de Bactérias/metabolismo
Cupriavidus necator/genética
Estabilidade Enzimática
Hidrogênio/metabolismo
Hidrogenase/genética
Hidrogenase/metabolismo
Hydrogenophilaceae/genética
NAD/metabolismo
[Pt] Tipo de publicação:JOURNAL ARTICLE; RESEARCH SUPPORT, NON-U.S. GOV'T
[Nm] Nome de substância:
0 (Bacterial Proteins); 0U46U6E8UK (NAD); 7YNJ3PO35Z (Hydrogen); EC 1.12.- (nickel-iron hydrogenase); EC 1.12.7.2 (Hydrogenase)
[Em] Mês de entrada:1803
[Cu] Atualização por classe:180309
[Lr] Data última revisão:
180309
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:171004
[St] Status:MEDLINE


  9 / 160240 MEDLINE  
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[PMID]:28466892
[Au] Autor:Bondí R; Longo F; Messina M; D'Angelo F; Visca P; Leoni L; Rampioni G
[Ad] Endereço:Department of Science, University Roma Tre, Rome, Italy. giordano.rampioni@uniroma3.it.
[Ti] Título:The multi-output incoherent feedforward loop constituted by the transcriptional regulators LasR and RsaL confers robustness to a subset of quorum sensing genes in Pseudomonas aeruginosa.
[So] Source:Mol Biosyst;13(6):1080-1089, 2017 Jun 01.
[Is] ISSN:1742-2051
[Cp] País de publicação:England
[La] Idioma:eng
[Ab] Resumo:Quorum sensing (QS) is an intercellular communication system which controls virulence-related phenotypes in the human pathogen Pseudomonas aeruginosa. LasR is the QS receptor protein which responds to the signal molecule N-(3-oxododecanoyl)homoserine lactone (3OC -HSL) and promotes signal production by increasing the transcription of the 3OC -HSL synthase gene, lasI. LasR also activates the expression of other genes, including rsaL, coding for the RsaL protein which acts as a transcriptional repressor of lasI. Direct gene activation and RsaL-mediated gene repression, both exerted by LasR on the expression of the output gene lasI, generate a regulatory network motif known as the type 1 incoherent feedforward loop (IFFL-1) that governs 3OC -HSL production. In addition to lasI, RsaL directly represses a set of LasR-activated genes; hence, the IFFL-1 generated by LasR and RsaL is a multi-output IFFL-1. Here we demonstrate that the multi-output IFFL-1 constituted by LasR and RsaL confers robustness with respect to fluctuations in the levels of LasR to the phenotypes controlled by both these transcriptional regulators (e.g. 3OC -HSL synthesis and pyocyanin production). In contrast, other virulence-related phenotypes controlled by LasR but not by RsaL (e.g. elastase and protease production) are sensitive to changes in LasR levels. Overall, the multi-output IFFL-1 generated by LasR and RsaL splits the QS regulon into two distinct sub-regulons with different robustness with respect to LasR fluctuations. This emerging regulatory property enhances the phenotypic plasticity of P. aeruginosa, thus contributing to its adaptation to changing environments.
[Mh] Termos MeSH primário: Proteínas de Bactérias/metabolismo
Pseudomonas aeruginosa/metabolismo
Pseudomonas aeruginosa/fisiologia
Percepção de Quorum
Proteínas Repressoras/metabolismo
Transativadores/metabolismo
[Mh] Termos MeSH secundário: 4-Butirolactona/análogos & derivados
4-Butirolactona/metabolismo
Proteínas de Bactérias/genética
Regulação da Expressão Gênica
Homosserina/análogos & derivados
Homosserina/metabolismo
Proteínas Repressoras/genética
Transativadores/genética
[Pt] Tipo de publicação:JOURNAL ARTICLE
[Nm] Nome de substância:
0 (Bacterial Proteins); 0 (LasR protein, Pseudomonas aeruginosa); 0 (N-(3-oxododecanoyl)homoserine lactone); 0 (Repressor Proteins); 0 (Trans-Activators); 0 (rsaL protein, Pseudomonas aeruginosa); 1192-20-7 (homoserine lactone); 6KA95X0IVO (Homoserine); OL659KIY4X (4-Butyrolactone)
[Em] Mês de entrada:1803
[Cu] Atualização por classe:180309
[Lr] Data última revisão:
180309
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:170504
[St] Status:MEDLINE
[do] DOI:10.1039/c7mb00040e


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[PMID]:29458684
[Au] Autor:Wise MG; Horvath E; Young K; Sahm DF; Kazmierczak KM
[Ad] Endereço:1​International Health Management Associates, Schaumburg, Illinois, USA.
[Ti] Título:Global survey of Klebsiella pneumoniae major porins from ertapenem non-susceptible isolates lacking carbapenemases.
[So] Source:J Med Microbiol;67(3):289-295, 2018 Mar.
[Is] ISSN:1473-5644
[Cp] País de publicação:England
[La] Idioma:eng
[Ab] Resumo:PURPOSE: To understand the diversity of porin disruption in Klebsiella pneumoniae, the major outer membrane protein (OMP) porins, OmpK35 and OmpK36, were examined in a set of isolates that did not harbour traditional carbapenem-hydrolysing enzymes, but nevertheless tested non-susceptible to ertapenem. METHODS: A world-wide collection of Klebsiella pneumoniae isolates that were part of the Study for Monitoring Antimicrobial Resistance Trends (SMART) surveillance project over the years 2008-2014 were characterised with regard to their ß-lactamase gene carriage and potential permeability defects. Four hundred and eighty-seven isolates that did not carry carbapenemase genes, but were non-susceptible to ertapenem, were investigated by sequence analysis of the genes encoding OmpK35 and OmpK36. Isolates without obvious genetic lesions in either major porin gene were further examined by outer membrane protein SDS-PAGE. RESULTS: The majority of isolates, 83.0 % (404/487), exhibited clear genetic disruption in either or both of the ompK35 and ompK36 genes. Among the proportion of the collection with the highest ertapenem MIC value (>4 mg l ), 60.5 % (115/190) showed mutation in both porin genes. Isolates without obvious genetic mutations were examined by SDS-PAGE, and 90.4 % (75/83) were found to lack or show altered expression of at least one of the major OMPs when compared to an ertapenem sensitive control strain. CONCLUSION: This study illustrates that porin deficiency in Klebsiella pneumoniae is a widespread phenomenon, and in combination with ESBLs and/or AmpC enzymes, likely accounts for the elevated ertapenem MICs observed in this study.
[Mh] Termos MeSH primário: Antibacterianos/farmacologia
Proteínas de Bactérias/genética
Klebsiella pneumoniae/genética
Porinas/genética
beta-Lactamas/farmacologia
[Mh] Termos MeSH secundário: Proteínas de Bactérias/metabolismo
Carbapenêmicos/farmacologia
DNA Bacteriano/genética
Eletroforese em Gel de Poliacrilamida
Seres Humanos
Infecções por Klebsiella/epidemiologia
Infecções por Klebsiella/microbiologia
Klebsiella pneumoniae/efeitos dos fármacos
Klebsiella pneumoniae/isolamento & purificação
Klebsiella pneumoniae/metabolismo
Testes de Sensibilidade Microbiana
Mutação
beta-Lactamases/genética
beta-Lactamases/metabolismo
[Pt] Tipo de publicação:JOURNAL ARTICLE
[Nm] Nome de substância:
0 (Anti-Bacterial Agents); 0 (Bacterial Proteins); 0 (Carbapenems); 0 (DNA, Bacterial); 0 (OmpK35 porin, Klebsiella pneumoniae); 0 (OmpK36 protein, Klebsiella pneumoniae); 0 (Porins); 0 (beta-Lactams); EC 3.5.2.6 (beta-Lactamases); EC 3.5.2.6 (carbapenemase); G32F6EID2H (ertapenem)
[Em] Mês de entrada:1803
[Cu] Atualização por classe:180308
[Lr] Data última revisão:
180308
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:180221
[St] Status:MEDLINE
[do] DOI:10.1099/jmm.0.000691



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