Base de dados : MEDLINE
Pesquisa : D12.776.097.200 [Categoria DeCS]
Referências encontradas : 2429 [refinar]
Mostrando: 1 .. 10   no formato [Detalhado]

página 1 de 243 ir para página                         

  1 / 2429 MEDLINE  
              next record last record
seleciona
para imprimir
Fotocópia
Texto completo
[PMID]:29304041
[Au] Autor:Gutiérrez-Del-Río I; Marín L; Fernández J; Álvarez San Millán M; Ferrero FJ; Valledor M; Campo JC; Cobián N; Méndez I; Lombó F
[Ad] Endereço:Research Group BIONUC, Departamento de Biología Funcional, Área de Microbiología, University of Oviedo, Oviedo, Principality of Asturias, Spain.
[Ti] Título:Development of a biosensor protein bullet as a fluorescent method for fast detection of Escherichia coli in drinking water.
[So] Source:PLoS One;13(1):e0184277, 2018.
[Is] ISSN:1932-6203
[Cp] País de publicação:United States
[La] Idioma:eng
[Ab] Resumo:Drinking water can be exposed to different biological contaminants from the source, through the pipelines, until reaching the final consumer or industry. Some of these are pathogenic bacteria and viruses which may cause important gastrointestinal or systemic diseases. The microbiological quality of drinking water relies mainly in monitoring three indicator bacteria of faecal origin, Escherichia coli, Enterococcus faecalis and Clostridium perfringens, which serve as early sentinels of potential health hazards for the population. Here we describe the analysis of three chimeric fluorescent protein bullets as biosensor candidates for fast detection of E. coli in drinking water. Two of the chimeric proteins (based on GFP-hadrurin and GFP-pb5 chimera proteins) failed with respect to specificity and/or sensitivity, but the GFP-colS4 chimera protein was able to carry out specific detection of E. coli in drinking water samples in a procedure encompassing about 8 min for final result and this biosensor protein was able to detect in a linear way between 20 and 103 CFU of this bacterium. Below 20 CFU, the system cannot differentiate presence or absence of the target bacterium. The fluorescence in this biosensor system is provided by the GFP subunit of the chimeric protein, which, in the case of the better performing sensor bullet, GFP-colS4 chimera, is covalently bound to a flexible peptide bridge and to a bacteriocin binding specifically to E. coli cells. Once bound to the target bacteria, the excitation step with 395 nm LED light causes emission of fluorescence from the GFP domain, which is amplified in a photomultiplier tube, and finally this signal is converted into an output voltage which can be associated with a CFU value and these data distributed along mobile phone networks, for example. This method, and the portable fluorimeter which has been developed for it, may contribute to reduce the analysis time for detecting E. coli presence in drinking water.
[Mh] Termos MeSH primário: Técnicas Biossensoriais/métodos
Água Potável/microbiologia
Escherichia coli/isolamento & purificação
Microbiologia da Água
[Mh] Termos MeSH secundário: Carga Bacteriana/métodos
Carga Bacteriana/estatística & dados numéricos
Colicinas/química
Colicinas/genética
Escherichia coli/genética
Fluorometria/instrumentação
Proteínas de Fluorescência Verde/química
Proteínas de Fluorescência Verde/genética
Seres Humanos
Proteínas Recombinantes de Fusão/química
Proteínas Recombinantes de Fusão/genética
[Pt] Tipo de publicação:JOURNAL ARTICLE; RESEARCH SUPPORT, NON-U.S. GOV'T
[Nm] Nome de substância:
0 (Colicins); 0 (Drinking Water); 0 (Recombinant Fusion Proteins); 147336-22-9 (Green Fluorescent Proteins)
[Em] Mês de entrada:1801
[Cu] Atualização por classe:180210
[Lr] Data última revisão:
180210
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:180106
[St] Status:MEDLINE
[do] DOI:10.1371/journal.pone.0184277


  2 / 2429 MEDLINE  
              first record previous record next record last record
seleciona
para imprimir
Fotocópia
Texto completo
[PMID]:29261665
[Au] Autor:Huynh L; Neale C; Pomès R; Chan HS
[Ad] Endereço:Department of Biochemistry, University of Toronto, Toronto, Ontario, Canada.
[Ti] Título:Molecular recognition and packing frustration in a helical protein.
[So] Source:PLoS Comput Biol;13(12):e1005909, 2017 12.
[Is] ISSN:1553-7358
[Cp] País de publicação:United States
[La] Idioma:eng
[Ab] Resumo:Biomolecular recognition entails attractive forces for the functional native states and discrimination against potential nonnative interactions that favor alternate stable configurations. The challenge posed by the competition of nonnative stabilization against native-centric forces is conceptualized as frustration. Experiment indicates that frustration is often minimal in evolved biological systems although nonnative possibilities are intuitively abundant. Much of the physical basis of minimal frustration in protein folding thus remains to be elucidated. Here we make progress by studying the colicin immunity protein Im9. To assess the energetic favorability of nonnative versus native interactions, we compute free energies of association of various combinations of the four helices in Im9 (referred to as H1, H2, H3, and H4) by extensive explicit-water molecular dynamics simulations (total simulated time > 300 µs), focusing primarily on the pairs with the largest native contact surfaces, H1-H2 and H1-H4. Frustration is detected in H1-H2 packing in that a nonnative packing orientation is significantly stabilized relative to native, whereas such a prominent nonnative effect is not observed for H1-H4 packing. However, in contrast to the favored nonnative H1-H2 packing in isolation, the native H1-H2 packing orientation is stabilized by H3 and loop residues surrounding H4. Taken together, these results showcase the contextual nature of molecular recognition, and suggest further that nonnative effects in H1-H2 packing may be largely avoided by the experimentally inferred Im9 folding transition state with native packing most developed at the H1-H4 rather than the H1-H2 interface.
[Mh] Termos MeSH primário: Modelos Moleculares
Conformação Proteica em alfa-Hélice
[Mh] Termos MeSH secundário: Colicinas/química
Biologia Computacional
Simulação por Computador
Simulação de Dinâmica Molecular
Dobramento de Proteína
Termodinâmica
[Pt] Tipo de publicação:JOURNAL ARTICLE; RESEARCH SUPPORT, NON-U.S. GOV'T
[Nm] Nome de substância:
0 (Colicins); 0 (colicin immunity proteins)
[Em] Mês de entrada:1801
[Cu] Atualização por classe:180128
[Lr] Data última revisão:
180128
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:171221
[St] Status:MEDLINE
[do] DOI:10.1371/journal.pcbi.1005909


  3 / 2429 MEDLINE  
              first record previous record next record last record
seleciona
para imprimir
Fotocópia
Texto completo
[PMID]:28543534
[Au] Autor:Zeinalzadeh N; Salmanian AH; Goujani G; Amani J; Ahangari G; Akhavian A; Jafari M
[Ad] Endereço:Department of Animal Science, Faculty of Natural Science, University of Tabriz, Tabriz.
[Ti] Título:A Chimeric protein of CFA/I, CS6 subunits and LTB/STa toxoid protects immunized mice against enterotoxigenic Escherichia coli.
[So] Source:Microbiol Immunol;61(7):272-279, 2017 Jul.
[Is] ISSN:1348-0421
[Cp] País de publicação:Australia
[La] Idioma:eng
[Ab] Resumo:Enterotoxigenic Escherichia Coli (ETEC) strains are the commonest bacteria causing diarrhea in children in developing countries and travelers to these areas. Colonization factors (CFs) and enterotoxins are the main virulence determinants in ETEC pathogenesis. Heterogeneity of CFs is commonly considered the bottleneck to developing an effective vaccine. It is believed that broad spectrum protection against ETEC would be achieved by induced anti-CF and anti-enterotoxin immunity simultaneously. Here, a fusion antigen strategy was used to construct a quadrivalent recombinant protein called 3CL and composed of CfaB, a structural subunit of CFA/I, and CS6 structural subunits, LTB and STa toxoid of ETEC. Its anti-CF and antitoxin immunogenicity was then assessed. To achieve high-level expression, the 3CL gene was synthesized using E. coli codon bias. Female BALB/C mice were immunized with purified recombinant 3CL. Immunized mice developed antibodies that were capable of detecting each recombinant subunit in addition to native CS6 protein and also protected the mice against ETEC challenge. Moreover, sera from immunized mice also neutralized STa toxin in a suckling mouse assay. These results indicate that 3CL can induce anti-CF and neutralizing antitoxin antibodies along with introducing CFA/I as a platform for epitope insertion.
[Mh] Termos MeSH primário: Antígenos de Bactérias/imunologia
Escherichia coli Enterotoxigênica/imunologia
Vacinas contra Escherichia coli/imunologia
Proteínas Recombinantes de Fusão/imunologia
Toxoides/imunologia
[Mh] Termos MeSH secundário: Animais
Anticorpos Antibacterianos/sangue
Anticorpos Neutralizantes/imunologia
Antígenos de Bactérias/genética
Antitoxinas/imunologia
Toxinas Bacterianas/genética
Toxinas Bacterianas/imunologia
Colicinas/genética
Colicinas/imunologia
Enterotoxinas/genética
Enterotoxinas/imunologia
Enterotoxinas/toxicidade
Infecções por Escherichia coli/imunologia
Infecções por Escherichia coli/prevenção & controle
Proteínas de Escherichia coli/genética
Proteínas de Escherichia coli/imunologia
Vacinas contra Escherichia coli/genética
Feminino
Camundongos
Camundongos Endogâmicos BALB C
Proteínas Recombinantes de Fusão/genética
Toxoides/genética
[Pt] Tipo de publicação:JOURNAL ARTICLE
[Nm] Nome de substância:
0 (Antibodies, Bacterial); 0 (Antibodies, Neutralizing); 0 (Antigens, Bacterial); 0 (Antitoxins); 0 (Bacterial Toxins); 0 (CS6 antigen, E coli); 0 (Colicins); 0 (Enterotoxins); 0 (Escherichia coli Proteins); 0 (Escherichia coli Vaccines); 0 (Recombinant Fusion Proteins); 0 (Toxoids); 0 (colicin 5 protein, E coli); 0 (heat stable toxin (E coli))
[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:170526
[St] Status:MEDLINE
[do] DOI:10.1111/1348-0421.12491


  4 / 2429 MEDLINE  
              first record previous record next record last record
seleciona
para imprimir
Fotocópia
Texto completo
[PMID]:28333314
[Au] Autor:Calcuttawala F; Hariharan C; Pazhani GP; Saha DR; Ramamurthy T
[Ad] Endereço:Division of Bacteriology, National Institute of Cholera and Enteric Diseases, Kolkata-700010, West Bengal, India.
[Ti] Título:Characterization of E-type colicinogenic plasmids from Shigella sonnei.
[So] Source:FEMS Microbiol Lett;364(7), 2017 Apr 01.
[Is] ISSN:1574-6968
[Cp] País de publicação:England
[La] Idioma:eng
[Ab] Resumo:Colicinogenic plasmids encode toxic proteins which have antagonistic activity against closely related bacteria. This study describes the molecular characterization of three colicinogenic plasmids designated as pSSE3, pSSE and pSSE2, each with a molecular size of ∼6 kb, identified in clinical isolates of Shigella sonnei. Sequence analysis revealed that pSSE and pSSE2 shared extensive sequence homology with each other and with Escherichia coli E-type colicinogenic plasmids. The plasmid pSSE3 lacked an additional gene imparting immunity to colicin E8, a unique feature not observed in any of the previously reported sequences of colicin E3 plasmids. Incomplete digestion of colicinogenic plasmids by restriction endonucleases, metachromatic staining with acridine orange and presence of single stranded initiation (ssi) region confirmed the coexistence of ssDNA along with dsDNA. Plasmid copy number as determined by real-time PCR was found to be about 20. Transmission electron microscopy revealed DNA impairment in test bacteria after colicin exposure. We hypothesize that S. sonnei has acquired E-group colicin plasmids from its close relative E. coli, with their sequences undergoing subtle changes depending on the cohabitation in the same milieu.
[Mh] Termos MeSH primário: Colicinas/genética
Plasmídeos
Shigella sonnei/genética
[Mh] Termos MeSH secundário: Colicinas/farmacologia
Enzimas de Restrição do DNA/metabolismo
DNA de Cadeia Simples
Disenteria Bacilar/microbiologia
Escherichia coli/genética
Microscopia Eletrônica de Transmissão
Reação em Cadeia da Polimerase em Tempo Real
Shigella sonnei/efeitos dos fármacos
Shigella sonnei/ultraestrutura
[Pt] Tipo de publicação:JOURNAL ARTICLE
[Nm] Nome de substância:
0 (Colicins); 0 (DNA, Single-Stranded); EC 3.1.21.- (DNA Restriction Enzymes)
[Em] Mês de entrada:1705
[Cu] Atualização por classe:170526
[Lr] Data última revisão:
170526
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:170324
[St] Status:MEDLINE
[do] DOI:10.1093/femsle/fnx060


  5 / 2429 MEDLINE  
              first record previous record next record last record
seleciona
para imprimir
Fotocópia
Texto completo
[PMID]:28268063
[Au] Autor:Micenková L; Benová A; Frankovicová L; Bosák J; Vrba M; Sevcíková A; Kmetová M; Smajs D
[Ad] Endereço:Department of Biology, Faculty of Medicine, Masaryk University, Kamenice 5, Building A6, 625 00 Brno, Czech Republic.
[Ti] Título:Human Escherichia coli isolates from hemocultures: Septicemia linked to urogenital tract infections is caused by isolates harboring more virulence genes than bacteraemia linked to other conditions.
[So] Source:Int J Med Microbiol;307(3):182-189, 2017 Apr.
[Is] ISSN:1618-0607
[Cp] País de publicação:Germany
[La] Idioma:eng
[Ab] Resumo:Escherichia coli is the most common cause of bloodstream infections and community-acquired sepsis. The main aim of this study was to determine virulence characteristics of E. coli isolates from hemocultures of patients with a primary disease of urogenital tract, digestive system, a neoplastic blood disease, or other conditions. Results from a set of 314 E. coli isolates from hemocultures were compared to data from a previously published analysis of 1283 fecal commensal E. coli isolates. Genetic profiling of the 314 E. coli isolates involved determination of phylogenetic group (A, B1, B2, D, C, E, and F), identification of 21 virulence factors, as well as 30 bacteriocin-encoding determinants. Pulsed-field gel electrophoresis was used to analyze clonal character of the hemoculture-derived isolates. The E. coli isolates from hemocultures belonged mainly to phylogenetic groups B2 (59.9%) and D (21.0%), and less frequently to phylogroups A (10.2%) and B1 (5.7%). Commonly detected virulence factors included adhesins (fimA 92.0%, pap 47.1%, and sfa 26.8%), and iron-uptake encoding genes (fyuA 87.9%, fepC 79.6%, aer 70.7%, iucC 68.2%, and ireA 13.7%), followed by colibactin (pks island 31.5%), and cytotoxic necrotizing factor (cnf1 11.1%). A higher frequency of microcin producers (and microcin M determinant) and a lower frequency of colicin Ib and microcin B17 was found in hemoculture-derived isolates compared to commensal fecal isolates. E. coli isolates from hemocultures harbored more virulence genes compared to fecal E. coli isolates. In addition, hemoculture E. coli isolates from patients with primary diagnosis related to urogenital tract were clearly different and more virulence genes were detected in these isolates compared to both fecal isolates and hemoculture-derived isolates from patients with blood and gastrointestinal diseases.
[Mh] Termos MeSH primário: Infecções por Escherichia coli/microbiologia
Escherichia coli/isolamento & purificação
Escherichia coli/patogenicidade
Sepse/microbiologia
Fatores de Virulência/genética
[Mh] Termos MeSH secundário: Adolescente
Adulto
Idoso
Idoso de 80 Anos ou mais
Criança
Pré-Escolar
Colicinas/genética
Eletroforese em Gel de Campo Pulsado
Escherichia coli/classificação
Escherichia coli/genética
Feminino
Gastroenterite/complicações
Genótipo
Seres Humanos
Lactente
Masculino
Meia-Idade
Neoplasias/complicações
Filogenia
Infecções Urinárias/complicações
Adulto Jovem
[Pt] Tipo de publicação:COMPARATIVE STUDY; JOURNAL ARTICLE
[Nm] Nome de substância:
0 (Colicins); 0 (Virulence Factors)
[Em] Mês de entrada:1704
[Cu] Atualização por classe:170417
[Lr] Data última revisão:
170417
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:170308
[St] Status:MEDLINE


  6 / 2429 MEDLINE  
              first record previous record next record last record
seleciona
para imprimir
Fotocópia
Texto completo
[PMID]:28261897
[Au] Autor:Langa S; Arqués JL; Medina M; Landete JM
[Ad] Endereço:Departamento de Tecnología de Alimentos, Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria (INIA), Madrid, Spain.
[Ti] Título:Coproduction of colicin V and lactic acid bacteria bacteriocins in lactococci and enterococci strains of biotechnological interest.
[So] Source:J Appl Microbiol;122(5):1159-1167, 2017 May.
[Is] ISSN:1365-2672
[Cp] País de publicação:England
[La] Idioma:eng
[Ab] Resumo:AIMS: The aim of this study was the coproduction in a single strain of the Gram-negative bacteriocin colicin V with other bacteriocins from lactic acid bacteria (LAB). METHODS AND RESULTS: Colicin V was expressed in Lactococcus and Enterococcus strains by replacing the colicin V leader peptide by the leader peptide and promoter of d-alanyl-d-alanine carboxypeptidase from Lactobacillus reuteri CECT925 in pNZ8048 (pNZ:LR-colV). The antimicrobial activity of colicin V against the indicator organism Escherichia coli DH5α in transformed strains was checked by agar diffusion assay and SDS-PAGE analysis. CONCLUSIONS: Lactococcus and Enterococcus transformed with pNZ:LR-colV were able to coproduce colicin V at high levels together with other LAB bacteriocins such as nisin A, nisin Z, lacticin 481 or enterocins A and B, obtaining broad-spectrum activity strains with large potential applications. SIGNIFICANCE AND IMPACT OF THE STUDY: The construction showed in this work could be used for the heterologous expression of other bacteriocins active against Gram-negative bacteria or wide-spectrum bacteriocins from LAB.
[Mh] Termos MeSH primário: Antibacterianos/metabolismo
Colicinas/biossíntese
Enterococcus/metabolismo
Ácido Láctico/metabolismo
Lactococcus/metabolismo
[Mh] Termos MeSH secundário: Antibacterianos/química
Antibacterianos/farmacologia
Colicinas/química
Colicinas/farmacologia
Enterococcus/química
Escherichia coli/efeitos dos fármacos
Microbiologia Industrial
Lactococcus/química
Sinais Direcionadores de Proteínas
[Pt] Tipo de publicação:JOURNAL ARTICLE
[Nm] Nome de substância:
0 (Anti-Bacterial Agents); 0 (Colicins); 0 (Protein Sorting Signals); 33X04XA5AT (Lactic Acid)
[Em] Mês de entrada:1707
[Cu] Atualização por classe:170703
[Lr] Data última revisão:
170703
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:170307
[St] Status:MEDLINE
[do] DOI:10.1111/jam.13439


  7 / 2429 MEDLINE  
              first record previous record next record last record
seleciona
para imprimir
Fotocópia
Texto completo
[PMID]:28223456
[Au] Autor:Ghequire MG; Kemland L; Anoz-Carbonell E; Buchanan SK; De Mot R
[Ad] Endereço:Centre of Microbial and Plant Genetics, KU Leuven, Heverlee, Belgium maarten.ghequire@biw.kuleuven.be.
[Ti] Título:A Natural Chimeric Bacteriocin with Novel Pore-Forming Activity Parasitizes the Ferrichrome Transporter.
[So] Source:MBio;8(1), 2017 Feb 21.
[Is] ISSN:2150-7511
[Cp] País de publicação:United States
[La] Idioma:eng
[Ab] Resumo:Modular bacteriocins represent a major group of secreted protein toxins with a narrow spectrum of activity, involved in interference competition between Gram-negative bacteria. These antibacterial proteins include a domain for binding to the target cell and a toxin module at the carboxy terminus. Self-inhibition of producers is provided by coexpression of linked immunity genes that transiently inhibit the toxin's activity through formation of bacteriocin-immunity complexes or by insertion in the inner membrane, depending on the type of toxin module. We demonstrate strain-specific inhibitory activity for PmnH, a bacteriocin with an unprecedented dual-toxin architecture, hosting both a colicin M domain, potentially interfering with peptidoglycan synthesis, and a novel colicin N-type domain, a pore-forming module distinct from the colicin Ia-type domain in pyocin S5. A downstream-linked gene product confers PmnH immunity upon susceptible strains. This protein, ImnH, has a transmembrane topology similar to that of colicin M-like and pore-forming immunity proteins, although homology with either of these is essentially absent. The enhanced killing activity of PmnH under iron-limited growth conditions reflects parasitism of the ferrichrome-type transporter for entry into target cells, a strategy shown here to be used as well by monodomain colicin M-like bacteriocins from pseudomonads. The integration of a second type of toxin module in a bacteriocin gene could offer a competitive advantage against bacteria displaying immunity against only one of both toxic activities. In their continuous struggle for ecological space, bacteria face a huge load of contenders, including phylogenetically related strains that compete for the same niche. One important group of secreted antibacterial proteins assisting in eliminating these rivals are modular bacteriocins of Gram-negative bacteria, comprising a domain for docking onto the cell envelope of a target cell, a translocation domain enabling subsequent cellular entry, and a toxin module that kills target cells via enzymatic or pore-forming activity. We here demonstrate the antagonistic function of a bacteriocin with unique architecture that combines a putative enzymatic colicin M-like domain and a novel pore-forming toxin module. For target cell recognition and entry, this bacteriocin hybrid takes advantage of the ferrichrome transporter, also parasitized by enzymatic bacteriocins devoid of the pore-forming module. Bacteriocins with an expanded toxin potential may represent an inventive bacterial strategy to alleviate immunity in target cells.
[Mh] Termos MeSH primário: Bacteriocinas/metabolismo
Ferricromo/metabolismo
Proteínas de Membrana Transportadoras/metabolismo
Pseudomonas aeruginosa/metabolismo
[Mh] Termos MeSH secundário: Bacteriocinas/genética
Transporte Biológico
Membrana Celular
Colicinas/genética
Pseudomonas aeruginosa/genética
[Pt] Tipo de publicação:JOURNAL ARTICLE
[Nm] Nome de substância:
0 (Bacteriocins); 0 (Colicins); 0 (Membrane Transport Proteins); 15630-64-5 (Ferrichrome)
[Em] Mês de entrada:1706
[Cu] Atualização por classe:170626
[Lr] Data última revisão:
170626
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:170223
[St] Status:MEDLINE


  8 / 2429 MEDLINE  
              first record previous record next record last record
seleciona
para imprimir
Fotocópia
Texto completo
[PMID]:28150898
[Au] Autor:Dos Santos LF; Biscola FT; Gonçalves EM; Guth BE
[Ad] Endereço:Adolfo Lutz Institute, Center of Bacteriology, Sao Paulo, Brazil.
[Ti] Título:Biofilm formation, invasiveness and colicinogeny in locus of enterocyte and effacement negative O113:H21 Shigatoxigenic Escherichia coli.
[So] Source:J Appl Microbiol;122(4):1101-1109, 2017 Apr.
[Is] ISSN:1365-2672
[Cp] País de publicação:England
[La] Idioma:eng
[Ab] Resumo:AIMS: Although Shiga toxins (Stx) are well-established virulence traits of O113:H21 Shigatoxigenic Escherichia coli (STEC) strains, a shortage in the knowledge of other virulence properties that may contribute to pathogenesis may exist in this serotype. This study investigated biofilm, invasiveness and colicinogeny capabilities in O113:H21 STEC isolated in Brazil, mostly from animal reservoirs. A search for genes that were reported to participate in the process of biofilm formation was also performed. METHODS AND RESULTS: The 34 O113:H21 STEC isolates analysed were assayed for biofilm production in polystyrene microplates. Genes for biofilm were investigated by PCR. Invasion of cell lineages was assessed in gentamicin protection assays and colicinogeny was investigated by phenotypic tests. Fifty per cent of the strains were biofilm formers, and 35% exhibited an invasive behaviour. The pattern of distribution of biofilm-related genes did not correlate with biofilm phenotypes observed, and a high percentage of the investigated strains were able to secrete colicins. CONCLUSION: Ability to form biofilm, invasiveness and colicinogeny is demonstrated for the first time in a collection of O113:H21 STEC. SIGNIFICANCE AND IMPACT OF THE STUDY: The ability to express three additional phenotypes besides Stx production may be a factor influencing the pathogenicity and persistence potential of O113:H21 STEC.
[Mh] Termos MeSH primário: Biofilmes/crescimento & desenvolvimento
Escherichia coli Shiga Toxigênica/patogenicidade
[Mh] Termos MeSH secundário: Animais
Células CACO-2
Linhagem Celular
Colicinas/metabolismo
Seres Humanos
Escherichia coli Shiga Toxigênica/genética
Escherichia coli Shiga Toxigênica/isolamento & purificação
Escherichia coli Shiga Toxigênica/fisiologia
Virulência
[Pt] Tipo de publicação:JOURNAL ARTICLE
[Nm] Nome de substância:
0 (Colicins)
[Em] Mês de entrada:1705
[Cu] Atualização por classe:170525
[Lr] Data última revisão:
170525
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:170203
[St] Status:MEDLINE
[do] DOI:10.1111/jam.13409


  9 / 2429 MEDLINE  
              first record previous record next record last record
seleciona
para imprimir
Fotocópia
[PMID]:27795317
[Au] Autor:Jakes KS
[Ad] Endereço:Albert Einstein College of Medicine, Department of Physiology and Biophysics, Bronx, New York, USA karen.jakes@einstein.yu.edu.
[Ti] Título:The Colicin E1 TolC Box: Identification of a Domain Required for Colicin E1 Cytotoxicity and TolC Binding.
[So] Source:J Bacteriol;199(1), 2017 Jan 01.
[Is] ISSN:1098-5530
[Cp] País de publicação:United States
[La] Idioma:eng
[Ab] Resumo:Colicins are protein toxins made by Escherichia coli to kill related bacteria that compete for scarce resources. All colicins must cross the target cell outer membrane in order to reach their intracellular targets. Normally, the first step in the intoxication process is the tight binding of the colicin to an outer membrane receptor protein via its central receptor-binding domain. It is shown here that for one colicin, E1, that step, although it greatly increases the efficiency of killing, is not absolutely necessary. For colicin E1, the second step, translocation, relies on the outer membrane/transperiplasmic protein TolC. The normal role of TolC in bacteria is as an essential component of a family of tripartite drug and toxin exporters, but for colicin E1, it is essential for its import. Colicin E1 and some N-terminal translocation domain peptides had been shown previously to bind in vitro to TolC and occlude channels made by TolC in planar lipid bilayer membranes. Here, a set of increasingly shorter colicin E1 translocation domain peptides was shown to bind to Escherichia coli in vivo and protect them from subsequent challenge by colicin E1. A segment of only 21 residues, the "TolC box," was thereby defined; that segment is essential for colicin E1 cytotoxicity and for binding of translocation domain peptides to TolC. IMPORTANCE: The Escherichia coli outer membrane/transperiplasmic protein TolC is normally an essential component of the bacterium's tripartite drug and toxin export machinery. The protein toxin colicin E1 instead uses TolC for its import into the cells that it kills, thereby subverting its normal role. Increasingly shorter constructs of the colicin's N-terminal translocation domain were used to define an essential 21-residue segment that is required for both colicin cytotoxicity and for binding of the colicin's translocation domain to bacteria, in order to protect them from subsequent challenge by active colicin E1. Thus, an essential TolC binding sequence of colicin E1 was identified and may ultimately lead to the development of drugs to block the bacterial drug export pathway.
[Mh] Termos MeSH primário: Proteínas da Membrana Bacteriana Externa/metabolismo
Colicinas/farmacologia
Proteínas de Escherichia coli/metabolismo
Escherichia coli/metabolismo
Proteínas de Membrana Transportadoras/metabolismo
[Mh] Termos MeSH secundário: Antibacterianos/farmacologia
Proteínas da Membrana Bacteriana Externa/genética
Escherichia coli/genética
Proteínas de Escherichia coli/genética
Regulação Bacteriana da Expressão Gênica/fisiologia
Proteínas de Membrana Transportadoras/genética
Modelos Moleculares
Ligação Proteica
Conformação Proteica
Domínios Proteicos
Transporte Proteico
[Pt] Tipo de publicação:JOURNAL ARTICLE
[Nm] Nome de substância:
0 (Anti-Bacterial Agents); 0 (Bacterial Outer Membrane Proteins); 0 (BtuB protein, E coli); 0 (Colicins); 0 (Escherichia coli Proteins); 0 (Membrane Transport Proteins); 0 (tolC protein, E coli)
[Em] Mês de entrada:1706
[Cu] Atualização por classe:170701
[Lr] Data última revisão:
170701
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:161101
[St] Status:MEDLINE


  10 / 2429 MEDLINE  
              first record previous record
seleciona
para imprimir
Fotocópia
Texto completo
[PMID]:27977665
[Au] Autor:Lechner M; Schwarz M; Opitz M; Frey E
[Ad] Endereço:Arnold-Sommerfeld-Center for Theoretical Physics and Center for NanoScience, Ludwig-Maximilians-Universität, Munich, Germany.
[Ti] Título:Hierarchical Post-transcriptional Regulation of Colicin E2 Expression in Escherichia coli.
[So] Source:PLoS Comput Biol;12(12):e1005243, 2016 Dec.
[Is] ISSN:1553-7358
[Cp] País de publicação:United States
[La] Idioma:eng
[Ab] Resumo:Post-transcriptional regulation of gene expression plays a crucial role in many bacterial pathways. In particular, the translation of mRNA can be regulated by trans-acting, small, non-coding RNAs (sRNAs) or mRNA-binding proteins, each of which has been successfully treated theoretically using two-component models. An important system that includes a combination of these modes of post-transcriptional regulation is the Colicin E2 system. DNA damage, by triggering the SOS response, leads to the heterogeneous expression of the Colicin E2 operon including the cea gene encoding the toxin colicin E2, and the cel gene that codes for the induction of cell lysis and release of colicin. Although previous studies have uncovered the system's basic regulatory interactions, its dynamical behavior is still unknown. Here, we develop a simple, yet comprehensive, mathematical model of the colicin E2 regulatory network, and study its dynamics. Its post-transcriptional regulation can be reduced to three hierarchically ordered components: the mRNA including the cel gene, the mRNA-binding protein CsrA, and an effective sRNA that regulates CsrA. We demonstrate that the stationary state of this system exhibits a pronounced threshold in the abundance of free mRNA. As post-transcriptional regulation is known to be noisy, we performed a detailed stochastic analysis, and found fluctuations to be largest at production rates close to the threshold. The magnitude of fluctuations can be tuned by the rate of production of the sRNA. To study the dynamics in response to an SOS signal, we incorporated the LexA-RecA SOS response network into our model. We found that CsrA regulation filtered out short-lived activation peaks and caused a delay in lysis gene expression for prolonged SOS signals, which is also seen in experiments. Moreover, we showed that a stochastic SOS signal creates a broad lysis time distribution. Our model thus theoretically describes Colicin E2 expression dynamics in detail and reveals the importance of the specific regulatory components for the timing of toxin release.
[Mh] Termos MeSH primário: Colicinas/genética
Proteínas de Escherichia coli/genética
Escherichia coli/genética
Regulação Bacteriana da Expressão Gênica/genética
RNA Bacteriano/genética
[Mh] Termos MeSH secundário: Animais
Colicinas/metabolismo
Cães
Escherichia coli/metabolismo
Proteínas de Escherichia coli/metabolismo
RNA Bacteriano/metabolismo
[Pt] Tipo de publicação:JOURNAL ARTICLE
[Nm] Nome de substância:
0 (Colicins); 0 (Escherichia coli Proteins); 0 (RNA, Bacterial)
[Em] Mês de entrada:1706
[Cu] Atualização por classe:170615
[Lr] Data última revisão:
170615
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:161216
[St] Status:MEDLINE
[do] DOI:10.1371/journal.pcbi.1005243



página 1 de 243 ir para página                         
   


Refinar a pesquisa
  Base de dados : MEDLINE Formulário avançado   

    Pesquisar no campo  
1  
2
3
 
           



Search engine: iAH v2.6 powered by WWWISIS

BIREME/OPAS/OMS - Centro Latino-Americano e do Caribe de Informação em Ciências da Saúde