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[PMID]:28456632
[Au] Autor:Laidlaw SM; Marukian S; Gilmore RH; Cashman SB; Nechyporuk-Zloy V; Rice CM; Dustin LB
[Ad] Endereço:Kennedy Institute of Rheumatology, The University of Oxford, Oxford, United Kingdom; Peter Medawar Building for Pathogen Research, The University of Oxford, Oxford, United Kingdom.
[Ti] Título:Tumor Necrosis Factor Inhibits Spread of Hepatitis C Virus Among Liver Cells, Independent From Interferons.
[So] Source:Gastroenterology;153(2):566-578.e5, 2017 Aug.
[Is] ISSN:1528-0012
[Cp] País de publicação:United States
[La] Idioma:eng
[Ab] Resumo:BACKGROUND & AIMS: Tumor necrosis factor (TNF) is an inflammatory cytokine expressed by human fetal liver cells (HFLCs) after infection with cell culture-derived hepatitis C virus (HCV). TNF has been reported to increase entry of HCV pseudoparticles into hepatoma cells and inhibit signaling by interferon alpha (IFNα), but have no effect on HCV-RNA replication. We investigated the effects of TNF on HCV infection of and spread among Huh-7 hepatoma cells and primary HFLCs. METHODS: Human hepatoma (Huh-7 and Huh-7.5) and primary HFLCs were incubated with TNF and/or recombinant IFNA2A, IFNB, IFNL1, and IFNL2 before or during HCV infection. We used 2 fully infectious HCV chimeric viruses of genotype 2A in these studies: J6/JFH (clone 2) and Jc1(p7-nsGluc2A) (Jc1G), which encodes a secreted luciferase reporter. We measured HCV replication, entry, spread, production, and release in hepatoma cells and HFLCs. RESULTS: TNF inhibited completion of the HCV infectious cycle in hepatoma cells and HFLCs in a dose-dependent and time-dependent manner. This inhibition required TNF binding to its receptor. Inhibition was independent of IFNα, IFNß, IFNL1, IFNL2, or Janus kinase signaling via signal transducer and activator of transcription. TNF reduced production of infectious viral particles by Huh-7 and HFLC, and thereby reduced the number of infected cells and focus size. TNF had little effect on HCV replicons and increased entry of HCV pseudoparticles. When cells were incubated with TNF before infection, the subsequent antiviral effects of IFNs were increased. CONCLUSIONS: In a cell culture system, we found TNF to have antiviral effects independently of, as well as in combination with, IFNs. TNF inhibits HCV infection despite increased HCV envelope glycoprotein-mediated infection of liver cells. These findings contradict those from other studies, which have reported that TNF blocks signal transduction in response to IFNs. The destructive inflammatory effects of TNF must be considered along with its antiviral effects.
[Mh] Termos MeSH primário: Antivirais/farmacologia
Hepacivirus/efeitos dos fármacos
Hepatite C/tratamento farmacológico
Interferons/farmacologia
Fator de Necrose Tumoral alfa/farmacologia
[Mh] Termos MeSH secundário: Carcinoma Hepatocelular/virologia
Linhagem Celular Tumoral
Genótipo
Hepacivirus/genética
Hepatócitos/efeitos dos fármacos
Hepatócitos/virologia
Seres Humanos
Janus Quinases/metabolismo
Fígado/citologia
Neoplasias Hepáticas/virologia
Receptores do Fator de Necrose Tumoral/metabolismo
Replicon/efeitos dos fármacos
Transdução de Sinais/efeitos dos fármacos
Fator de Necrose Tumoral alfa/metabolismo
Replicação Viral/efeitos dos fármacos
[Pt] Tipo de publicação:JOURNAL ARTICLE
[Nm] Nome de substância:
0 (Antiviral Agents); 0 (Receptors, Tumor Necrosis Factor); 0 (Tumor Necrosis Factor-alpha); 9008-11-1 (Interferons); EC 2.7.10.2 (Janus Kinases)
[Em] Mês de entrada:1708
[Cu] Atualização por classe:180307
[Lr] Data última revisão:
180307
[Sb] Subgrupo de revista:AIM; IM
[Da] Data de entrada para processamento:170501
[St] Status:MEDLINE


  2 / 2994 MEDLINE  
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[PMID]:28747506
[Au] Autor:Kim JY; Wang L; Lee J; Ou JJ
[Ad] Endereço:Department of Molecular Microbiology and Immunology, University of Southern California Keck School of Medicine, Los Angeles, California, USA.
[Ti] Título:Hepatitis C Virus Induces the Localization of Lipid Rafts to Autophagosomes for Its RNA Replication.
[So] Source:J Virol;91(20), 2017 Oct 15.
[Is] ISSN:1098-5514
[Cp] País de publicação:United States
[La] Idioma:eng
[Ab] Resumo:Autophagy plays important roles in maintaining cellular homeostasis. It uses double- or multiple-membrane vesicles termed autophagosomes to remove protein aggregates and damaged organelles from the cytoplasm for recycling. Hepatitis C virus (HCV) has been shown to induce autophagy to enhance its own replication. Here we describe a procedure that combines membrane flotation and affinity chromatography for the purification of autophagosomes from cells that harbor an HCV subgenomic RNA replicon. The purified autophagosomes had double- or multiple-membrane structures with a diameter ranging from 200 nm to 600 nm. The analysis of proteins associated with HCV-induced autophagosomes by proteomics led to the identification of HCV nonstructural proteins as well as proteins involved in membrane trafficking. Notably, caveolin-1, caveolin-2, and annexin A2, which are proteins associated with lipid rafts, were also identified. The association of lipid rafts with HCV-induced autophagosomes was confirmed by Western blotting, immunofluorescence microscopy, and immunoelectron microscopy. Their association with autophagosomes was also confirmed in HCV-infected cells. The association of lipid rafts with autophagosomes was specific to HCV, as it was not detected in autophagosomes induced by nutrient starvation. Further analysis indicated that the autophagosomes purified from HCV replicon cells could mediate HCV RNA replication in a lipid raft-dependent manner, as the depletion of cholesterol, a major component of lipid rafts, from autophagosomes abolished HCV RNA replication. Our studies thus demonstrated that HCV could specifically induce the association of lipid rafts with autophagosomes for its RNA replication. HCV can cause severe liver diseases, including cirrhosis and hepatocellular carcinoma, and is one of the most important human pathogens. Infection with HCV can lead to the reorganization of membrane structures in its host cells, including the induction of autophagosomes. In this study, we developed a procedure to purify HCV-induced autophagosomes and demonstrated that HCV could induce the localization of lipid rafts to autophagosomes to mediate its RNA replication. This finding provided important information for further understanding the life cycle of HCV and its interaction with the host cells.
[Mh] Termos MeSH primário: Autofagossomos/fisiologia
Hepacivirus/fisiologia
Microdomínios da Membrana/fisiologia
Replicação Viral
[Mh] Termos MeSH secundário: Anexina A2/química
Anexina A2/isolamento & purificação
Autofagossomos/química
Autofagossomos/virologia
Autofagia
Western Blotting
Caveolina 1/química
Caveolina 1/isolamento & purificação
Caveolina 2/química
Caveolina 2/isolamento & purificação
Linhagem Celular
Colesterol/análise
Cromatografia de Afinidade
Interações Hospedeiro-Patógeno
Seres Humanos
Microdomínios da Membrana/química
Microdomínios da Membrana/virologia
Microscopia de Fluorescência
Microscopia Imunoeletrônica
Proteômica
RNA Viral/fisiologia
Replicon
Proteínas não Estruturais Virais/metabolismo
[Pt] Tipo de publicação:JOURNAL ARTICLE
[Nm] Nome de substância:
0 (Annexin A2); 0 (Caveolin 1); 0 (Caveolin 2); 0 (RNA, Viral); 0 (Viral Nonstructural Proteins); 97C5T2UQ7J (Cholesterol)
[Em] Mês de entrada:1710
[Cu] Atualização por classe:180124
[Lr] Data última revisão:
180124
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:170728
[St] Status:MEDLINE


  3 / 2994 MEDLINE  
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[PMID]:28779235
[Au] Autor:Zhang QY; Li XD; Liu SQ; Deng CL; Zhang B; Ye HQ
[Ad] Endereço:Key Laboratory of Special Pathogens and Biosafety, Center for Emerging Infectious Diseases, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan, 430071, China.
[Ti] Título:Development of a stable Japanese encephalitis virus replicon cell line for antiviral screening.
[So] Source:Arch Virol;162(11):3417-3423, 2017 Nov.
[Is] ISSN:1432-8798
[Cp] País de publicação:Austria
[La] Idioma:eng
[Ab] Resumo:Japanese encephalitis virus (JEV), an important pathogen in Eastern and Southern Asia and the Pacific, has spread to Australia and other territories in recent years. Although the vaccine for JEV has been used in some countries, development of efficient antiviral drugs is still an urgent requirement. Replicon systems have been widely used in the research of viral replication and antiviral screening for West Nile virus (WNV), yellow fever virus (YFV) and dengue virus (DENV). Here, a novel JEV replicon harboring the Rluc and Pac gene (JEV-Pac-Rluc-Rep) was constructed. Furthermore, we established a BHK-21 cell line harboring JEV-Pac-Rluc-Rep (BHK-21 cell line) through continuous puromycin selection. Characterization of cell line stability showed that the replicon RNA could persistently replicate in this cell line for at least up to 10 rounds of passage. Using a known flavivirus inhibitor, the JEV replicon cell line was validated for antiviral screening. The JEV replicon cell line will be a valuable tool for both compound screening and viral replication studies.
[Mh] Termos MeSH primário: Antivirais/uso terapêutico
Vírus da Encefalite Japonesa (Espécie)/fisiologia
[Mh] Termos MeSH secundário: Animais
Linhagem Celular
Cricetinae
Puromicina
Replicon/genética
Replicon/fisiologia
Replicação Viral
[Pt] Tipo de publicação:JOURNAL ARTICLE
[Nm] Nome de substância:
0 (Antiviral Agents); 4A6ZS6Q2CL (Puromycin)
[Em] Mês de entrada:1710
[Cu] Atualização por classe:171025
[Lr] Data última revisão:
171025
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:170806
[St] Status:MEDLINE
[do] DOI:10.1007/s00705-017-3508-9


  4 / 2994 MEDLINE  
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Rahal, Paula
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[PMID]:28699869
[Au] Autor:Campos GRF; Bittar C; Jardim ACG; Shimizu JF; Batista MN; Paganini ER; Assis LR; Bartlett C; Harris M; Bolzani VDS; Regasini LO; Rahal P
[Ad] Endereço:1​Institute of Bioscience, Language and Exact Science, IBILCE, UNESP - São Paulo State University, São José do Rio Preto, SP, Brazil.
[Ti] Título:Hepatitis C virus in vitro replication is efficiently inhibited by acridone Fac4.
[So] Source:J Gen Virol;98(7):1693-1701, 2017 Jul.
[Is] ISSN:1465-2099
[Cp] País de publicação:England
[La] Idioma:eng
[Ab] Resumo:Hepatitis C virus (HCV) affects about 170 million people worldwide. The current treatment has a high cost and variable response rates according to the virus genotype. Acridones, a group of compounds extracted from natural sources, showed potential antiviral actions against HCV. Thus, this study aimed to evaluate the effect of a panel of 14 synthetic acridones on the HCV life cycle. The compounds were screened using an Huh7.5 cell line stably harbouring the HCV genotype 2a subgenomic replicon SGR-Feo-JFH-1. Cells were incubated in the presence or absence of compounds for 72 h and cell viability and replication levels were assessed by MTT and luciferase assays, respectively. At a concentration of 5 µM the acridone Fac4 exhibited a >90 % inhibition of HCV replication with no effect on cell viability. The effects of Fac4 on virus replication, entry and release steps were evaluated in Huh7.5 cells infected with the JFH-1 isolate of HCV (HCVcc). Fac4 inhibited JFH-1 replication to approximately 70 %, while no effect was observed on virus entry. The antiviral activity of Fac4 was also observed on viral release, with almost 80 % of inhibition. No inhibitory effect was observed against genotype 3 replication. Fac4 was able to intercalate into dsRNA, however did not inhibit NS5B polymerase activity or translation driven by the HCV IRES. Although its mode of action is partly understood, Fac4 presents significant inhibition of HCV replication and can therefore be considered as a candidate for the development of a future anti-HCV treatment.
[Mh] Termos MeSH primário: Acridonas/farmacologia
Antivirais/farmacologia
Hepacivirus/efeitos dos fármacos
Hepacivirus/fisiologia
Replicação Viral/efeitos dos fármacos
[Mh] Termos MeSH secundário: Acridonas/síntese química
Antivirais/síntese química
Genoma Viral/efeitos dos fármacos
Hepacivirus/genética
Hepatite C/virologia
Seres Humanos
Replicon/efeitos dos fármacos
Internalização do Vírus/efeitos dos fármacos
[Pt] Tipo de publicação:JOURNAL ARTICLE
[Nm] Nome de substância:
0 (Acridones); 0 (Antiviral Agents)
[Em] Mês de entrada:1709
[Cu] Atualização por classe:170921
[Lr] Data última revisão:
170921
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:170713
[St] Status:MEDLINE
[do] DOI:10.1099/jgv.0.000808


  5 / 2994 MEDLINE  
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[PMID]:28650160
[Au] Autor:Zhen L; Dai L; Wen X; Yao L; Jin X; Yang XW; Zhao W; Yu SQ; Yuan H; Wang G; Sun H
[Ad] Endereço:Jiangsu Key Laboratory of Drug Discovery for Metabolic Disease and State Key Laboratory of Natural Medicines, China Pharmaceutical University , 24 Tongjia Xiang, Nanjing 210009, China.
[Ti] Título:Discovery of Novel Nucleotide Prodrugs with Improved Potency Against HCV Variants Carrying NS5B S282T Mutation.
[So] Source:J Med Chem;60(14):6077-6088, 2017 Jul 27.
[Is] ISSN:1520-4804
[Cp] País de publicação:United States
[La] Idioma:eng
[Ab] Resumo:Resistant HCV variants carrying NS5B S282T mutation confer reduced sensitivity to sofosbuvir, the sole marketed NS5B polymerase inhibitor. On the basis of the finding that 2'-α-F-2'-ß-C-methylcytidine 5'-triphosphate (8) was more potent than sofosbuvir's active metabolite on inhibition of both wild-type and S282T mutant polymerase, a dual-prodrug approach has been established. Twenty-nine phosphoramidates with N -modified cytosine were designed, synthesized, and evaluated for anti-HCV activity. The results showed that compounds 4c-4e and 4m (EC = 0.19-0.25 µM) exhibited comparable potency to that of sofosbuvir (EC = 0.15 µM) on inhibition of wild-type replicons. Notably, 4c (EC = 0.366 µM) was 1.5-fold more potent than sofosbuvir (EC = 0.589 µM) on inhibition of S282T mutant replicons. In vitro metabolic studies disclosed the possible metabolic pathways of 4c. The toxicity study results indicated a good safety profile of 4c. Together, 4c-4e and 4m hold promise for drug development for the treatment of HCV infection, especially the resistant variants with NS5B S282T mutation.
[Mh] Termos MeSH primário: Alanina/análogos & derivados
Antivirais/química
Citidina Monofosfato/análogos & derivados
Hepacivirus/efeitos dos fármacos
Nucleotídeos/síntese química
Pró-Fármacos/síntese química
[Mh] Termos MeSH secundário: Alanina/síntese química
Alanina/farmacocinética
Alanina/farmacologia
Animais
Antivirais/síntese química
Antivirais/farmacologia
Linhagem Celular Tumoral
Citidina Monofosfato/síntese química
Citidina Monofosfato/farmacocinética
Citidina Monofosfato/farmacologia
Cães
Feminino
Hepacivirus/genética
Seres Humanos
Fígado/metabolismo
Masculino
Mutação
Nucleotídeos/farmacocinética
Nucleotídeos/farmacologia
Pró-Fármacos/farmacocinética
Pró-Fármacos/farmacologia
RNA Replicase/genética
Replicon
Estereoisomerismo
Relação Estrutura-Atividade
Proteínas não Estruturais Virais/genética
[Pt] Tipo de publicação:JOURNAL ARTICLE
[Nm] Nome de substância:
0 (Antiviral Agents); 0 (NS-5 protein, hepatitis C virus); 0 (Nucleotides); 0 (Prodrugs); 0 (Viral Nonstructural Proteins); 0 (isopropyl 2-((((5-(4-butyramido-2-oxopyrimidin-1(2H)-yl)-4-fluoro-3-hydroxy-4-methyltetrahydrofuran-2-yl)methoxy)(phenoxy)phosphoryl)amino)propanoate); EC 2.7.7.48 (RNA Replicase); F469818O25 (Cytidine Monophosphate); OF5P57N2ZX (Alanine)
[Em] Mês de entrada:1709
[Cu] Atualização por classe:170906
[Lr] Data última revisão:
170906
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:170627
[St] Status:MEDLINE
[do] DOI:10.1021/acs.jmedchem.7b00262


  6 / 2994 MEDLINE  
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[PMID]:28622507
[Au] Autor:Graham JE; Marians KJ; Kowalczykowski SC
[Ad] Endereço:Department of Microbiology and Molecular Genetics and Department of Molecular and Cellular Biology, University of California, Davis, Davis, CA 95616, USA.
[Ti] Título:Independent and Stochastic Action of DNA Polymerases in the Replisome.
[So] Source:Cell;169(7):1201-1213.e17, 2017 Jun 15.
[Is] ISSN:1097-4172
[Cp] País de publicação:United States
[La] Idioma:eng
[Ab] Resumo:It has been assumed that DNA synthesis by the leading- and lagging-strand polymerases in the replisome must be coordinated to avoid the formation of significant gaps in the nascent strands. Using real-time single-molecule analysis, we establish that leading- and lagging-strand DNA polymerases function independently within a single replisome. Although average rates of DNA synthesis on leading and lagging strands are similar, individual trajectories of both DNA polymerases display stochastically switchable rates of synthesis interspersed with distinct pauses. DNA unwinding by the replicative helicase may continue during such pauses, but a self-governing mechanism, where helicase speed is reduced by ∼80%, permits recoupling of polymerase to helicase. These features imply a more dynamic, kinetically discontinuous replication process, wherein contacts within the replisome are continually broken and reformed. We conclude that the stochastic behavior of replisome components ensures complete DNA duplication without requiring coordination of leading- and lagging-strand synthesis. PAPERCLIP.
[Mh] Termos MeSH primário: Replicação do DNA
DNA Polimerase Dirigida por DNA/metabolismo
Escherichia coli/metabolismo
[Mh] Termos MeSH secundário: DNA Helicases/metabolismo
Escherichia coli/enzimologia
Microscopia de Fluorescência/métodos
Modelos Biológicos
Replicon
[Pt] Tipo de publicação:JOURNAL ARTICLE
[Nm] Nome de substância:
EC 2.7.7.7 (DNA-Directed DNA Polymerase); EC 3.6.4.- (DNA Helicases)
[Em] Mês de entrada:1707
[Cu] Atualização por classe:170810
[Lr] Data última revisão:
170810
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:170617
[St] Status:MEDLINE


  7 / 2994 MEDLINE  
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[PMID]:28609784
[Au] Autor:Hagedorn C; Gogol-Döring A; Schreiber S; Epplen JT; Lipps HJ
[Ad] Endereço:University of Witten/Herdecke, ZBAF, Institute of Cell Biology, Stockumer Strasse 10, 58453 Witten, Germany.
[Ti] Título:Genome-wide profiling of S/MAR-based replicon contact sites.
[So] Source:Nucleic Acids Res;45(13):7841-7854, 2017 Jul 27.
[Is] ISSN:1362-4962
[Cp] País de publicação:England
[La] Idioma:eng
[Ab] Resumo:Autonomously replicating vectors represent a simple and versatile model system for genetic modifications, but their localization in the nucleus and effect on endogenous gene expression is largely unknown. Using circular chromosome conformation capture we mapped genomic contact sites of S/MAR-based replicons in HeLa cells. The influence of cis-active sequences on genomic localization was assessed using replicons containing either an insulator sequence or an intron. While the original and the insulator-containing replicons displayed distinct contact sites, the intron-containing replicon showed a rather broad genomic contact pattern. Our results indicate a preference for certain chromatin structures and a rather non-dynamic behaviour during mitosis. Independent of inserted cis-active elements established vector molecules reside preferentially within actively transcribed regions, especially within promoter sequences and transcription start sites. However, transcriptome analyses revealed that established S/MAR-based replicons do not alter gene expression profiles of host genome. Knowledge of preferred contact sites of exogenous DNA, e.g. viral or non-viral episomes, contribute to our understanding of episome behaviour in the nucleus and can be used for vector improvement and guiding of DNA sequences to specific subnuclear sites.
[Mh] Termos MeSH primário: Replicon
[Mh] Termos MeSH secundário: Sítios de Ligação/genética
Cromatina/genética
Cromatina/metabolismo
DNA/genética
DNA/metabolismo
DNA Polimerase II/metabolismo
Replicação do DNA/genética
Perfilação da Expressão Gênica
Vetores Genéticos
Genoma Humano
Células HeLa
Seres Humanos
Modelos Genéticos
Plasmídeos/genética
Plasmídeos/metabolismo
Origem de Replicação
[Pt] Tipo de publicação:JOURNAL ARTICLE
[Nm] Nome de substância:
0 (Chromatin); 9007-49-2 (DNA); EC 2.7.7.- (DNA Polymerase II)
[Em] Mês de entrada:1710
[Cu] Atualização por classe:171010
[Lr] Data última revisão:
171010
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:170614
[St] Status:MEDLINE
[do] DOI:10.1093/nar/gkx522


  8 / 2994 MEDLINE  
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Texto completo SciELO Brasil
[PMID]:28558260
[Au] Autor:Frazão MR; Andrade LN; Darini ALC; Falcão JP
[Ad] Endereço:Universidade de São Paulo (USP), Faculdade de Ciências Farmacêuticas de Ribeirão Preto (FCFRP), Departamento de Análises Clínicas, Toxicológicas e Bromatológicas (DACTB), Ribeirão Preto, SP, Brazil.
[Ti] Título:Antimicrobial resistance and plasmid replicons in Yersinia enterocolitica strains isolated in Brazil in 30 years.
[So] Source:Braz J Infect Dis;21(4):477-480, 2017 Jul - Aug.
[Is] ISSN:1678-4391
[Cp] País de publicação:Brazil
[La] Idioma:eng
[Ab] Resumo:Some studies evaluated the resistance profile of the Y. enterocolitica strains isolated in diverse countries. However, in Brazil the isolation and the study of Y. enterocolitica are not common and therefore information about the antimicrobial resistance profile of this species in this country is scarce. Therefore, the aim of this study was to evaluate the antimicrobial resistance of Y. enterocolitica of biotypes 1A, 2 and 4 isolated from clinical and non-clinical sources between 1979 and 2012, in Brazil. This study showed that some Yersinia enterocolitica of different biotypes remain susceptible to antimicrobials used for gastroenteritis treatment. Moreover, neither acquired resistance genes nor diversity of plasmids replicons were found; however, variation in the in vitro intrinsic resistant pattern was detected, except the non-resistance to cefoxitin in all strains. Notwithstanding, due to epidemiological link between Y. enterocolitica and the pork production chain, monitoring plasmid acquired resistance in Y. enterocolitica could also be considered for antimicrobial resistance control purposes and food safety measures.
[Mh] Termos MeSH primário: Antibacterianos/farmacologia
Farmacorresistência Bacteriana/genética
Replicon/genética
Yersinia enterocolitica/efeitos dos fármacos
[Mh] Termos MeSH secundário: Animais
Brasil
Seres Humanos
Testes de Sensibilidade Microbiana
Plasmídeos/genética
Fatores de Tempo
Yersinia enterocolitica/genética
[Pt] Tipo de publicação:JOURNAL ARTICLE
[Nm] Nome de substância:
0 (Anti-Bacterial Agents)
[Em] Mês de entrada:1708
[Cu] Atualização por classe:170825
[Lr] Data última revisão:
170825
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:170531
[St] Status:MEDLINE


  9 / 2994 MEDLINE  
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[PMID]:28525572
[Au] Autor:Lorenzo-Díaz F; Fernández-López C; Lurz R; Bravo A; Espinosa M
[Ad] Endereço:Departamento de Bioquímica, Microbiología, Biología Celular y Genética, Universidad de La Laguna. Av. Astrofísico Francisco Sánchez s/n, 38071 Santa Cruz de Tenerife, Spain.
[Ti] Título:Crosstalk between vertical and horizontal gene transfer: plasmid replication control by a conjugative relaxase.
[So] Source:Nucleic Acids Res;45(13):7774-7785, 2017 Jul 27.
[Is] ISSN:1362-4962
[Cp] País de publicação:England
[La] Idioma:eng
[Ab] Resumo:Horizontal gene transfer is a key process in the evolution of bacteria and also represents a source of genetic variation in eukaryotes. Among elements participating in gene transfer, thousands of small (<10 kb) mobile bacterial plasmids that replicate by the rolling circle mechanism represent a driving force in the spread of antibiotic resistances. In general, these plasmids are built as genetic modules that encode a replicase, an antibiotic-resistance determinant, and a relaxase that participates in their conjugative mobilization. Further, they control their relatively high copy number (∼30 copies per genome equivalent) by antisense RNAs alone or combined with a repressor protein. We report here that the MobM conjugative relaxase encoded by the promiscuous plasmid pMV158 participates in regulation of the plasmid copy number by transcriptional repression of the antisense RNA, thus increasing the number of plasmid molecules ready to be horizontally transferred (mobilization) and/or vertically inherited (replication). This type of crosstalk between genetic modules involved in vertical and horizontal gene flow has not been reported before.
[Mh] Termos MeSH primário: Proteínas de Bactérias/metabolismo
Endodesoxirribonucleases/metabolismo
Transferência Genética Horizontal
Plasmídeos/genética
[Mh] Termos MeSH secundário: Proteínas de Bactérias/genética
Sítios de Ligação
Conjugação Genética
Variações do Número de Cópias de DNA
Replicação do DNA
DNA Bacteriano/química
DNA Bacteriano/genética
DNA Bacteriano/metabolismo
DNA Super-Helicoidal/química
DNA Super-Helicoidal/genética
DNA Super-Helicoidal/metabolismo
Farmacorresistência Bacteriana/genética
Endodesoxirribonucleases/genética
Escherichia coli/genética
Escherichia coli/metabolismo
Evolução Molecular
Fluxo Gênico
Microscopia Eletrônica
Modelos Biológicos
Regiões Promotoras Genéticas
Replicon
Streptococcus pneumoniae/genética
Streptococcus pneumoniae/metabolismo
[Pt] Tipo de publicação:JOURNAL ARTICLE
[Nm] Nome de substância:
0 (Bacterial Proteins); 0 (DNA, Bacterial); 0 (DNA, Superhelical); EC 3.1.- (Endodeoxyribonucleases); EC 3.1.25.- (MobM protein, bacteria)
[Em] Mês de entrada:1710
[Cu] Atualização por classe:171010
[Lr] Data última revisão:
171010
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:170520
[St] Status:MEDLINE
[do] DOI:10.1093/nar/gkx450


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[PMID]:28379732
[Au] Autor:Jiang W; Men S; Kong L; Ma S; Yang Y; Wang Y; Yuan Q; Cheng G; Zou W; Wang H
[Ad] Endereço:1 Key Laboratory of Bio-Resources and Eco-Environment, Ministry of Education, College of Life Science, Sichuan University , Chengdu, China .
[Ti] Título:Prevalence of Plasmid-Mediated Fosfomycin Resistance Gene fosA3 Among CTX-M-Producing Escherichia coli Isolates from Chickens in China.
[So] Source:Foodborne Pathog Dis;14(4):210-218, 2017 Apr.
[Is] ISSN:1556-7125
[Cp] País de publicação:United States
[La] Idioma:eng
[Ab] Resumo:The aim of this study was to investigate the prevalence of fosfomycin resistance gene fosA3 and characterize plasmids harboring fosA3 among CTX-M-producing Escherichia coli from chickens in China. A total of 234 CTX-M-producing E. coli isolates collected from chickens from 2014 to 2016 were screened for the presence of plasmid-mediated fosfomycin resistance genes (fosA, fosA3, and fosC2). Clonal relatedness of fosA3-positive isolates was determined by pulsed-field gel electrophoresis (PFGE) and multilocus sequence typing (MLST). The genetic environment of fosA3 was analyzed by polymerase chain reaction (PCR) mapping. Plasmids were studied by using conjugation experiments, PCR-based replicon typing and plasmid MLST. Sixty-four (27.4%) fosA3-positive E. coli isolates were identified in this study. The gene bla (31/64) was predominant among these strains, followed by bla (18/64) and bla (14/64). Various PFGE patterns and sequence types (STs) indicated that these isolates were clonally unrelated. Seven different genetic environments of fosA3 were identified and two new combinations (ISEcp1-bla -ΔIS903D-IS26-fosA3-orf1-orf2-Δorf3-IS26 and IS26-ISEcp1-bla -orf477-bla -IS26-fosA3-orf1-orf2-Δorf3-IS26) were discovered for the first time. Conjugation experiments were successful for 47 isolates and 33 transconjugants harbored a single plasmid. Plasmids carrying fosA3 belonged to incompatibility group IncFII (17/33), IncI1 (2/33), IncHI2 (3/33), and IncB/O (1/33). F33:A-:B- plasmids carrying bla , IncHI2/ST3 plasmids carrying bla , and F2:A-:B-plasmids carrying bla were found in E. coli isolates from different provinces. Our results revealed a considerable prevalence of fosA3 gene among CTX-M-producing E. coli with clonal diversity from chickens in China. The transmission of different kinds of plasmids is responsible for the dissemination of fosA3 in chicken farms in China.
[Mh] Termos MeSH primário: Antibacterianos/farmacologia
Galinhas/microbiologia
Farmacorresistência Bacteriana Múltipla/genética
Escherichia coli/genética
Fosfomicina/farmacologia
[Mh] Termos MeSH secundário: Animais
Técnicas de Tipagem Bacteriana
China
DNA Bacteriano/isolamento & purificação
Eletroforese em Gel de Campo Pulsado
Escherichia coli/isolamento & purificação
Proteínas de Escherichia coli/genética
Proteínas de Escherichia coli/metabolismo
Testes de Sensibilidade Microbiana
Tipagem de Sequências Multilocus
Plasmídeos/genética
Replicon
Análise de Sequência de DNA
[Pt] Tipo de publicação:JOURNAL ARTICLE
[Nm] Nome de substância:
0 (Anti-Bacterial Agents); 0 (DNA, Bacterial); 0 (Escherichia coli Proteins); 0 (FosA(3) protein, E coli); 2N81MY12TE (Fosfomycin)
[Em] Mês de entrada:1710
[Cu] Atualização por classe:171016
[Lr] Data última revisão:
171016
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:170406
[St] Status:MEDLINE
[do] DOI:10.1089/fpd.2016.2230



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