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Pesquisa : D08.811.739.650 [Categoria DeCS]
Referências encontradas : 7 [refinar]
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Id: lil-762905
Autor: Yassien, M.A.M.; Elfaky, M.A..
Título: Overexpression of Salmonella enterica serovar Typhi recA gene confers fluoroquinolone resistance in Escherichia coli DH5α
Fonte: Braz. j. med. biol. res = Rev. bras. pesqui. méd. biol;48(11):990-995, Nov. 2015. tab, graf.
Idioma: en.
Projeto: Deanship of Scientific Research (DSR), King Abdulaziz University, Jeddah, Saudi Arabia.
Resumo: A spontaneous fluoroquinolone-resistant mutant (STM1) was isolated from its parent Salmonella enterica serovar Typhi (S. Typhi) clinical isolate. Unlike its parent isolate, this mutant has selective resistance to fluoroquinolones without any change in its sensitivity to various other antibiotics. DNA gyrase assays revealed that the fluoroquinolone resistance phenotype of the STM1 mutant did not result from alteration of the fluoroquinolone sensitivity of the DNA gyrase isolated from it. To study the mechanism of fluoroquinolone resistance, a genomic library from the STM1 mutant was constructed in Escherichia coli DH5α and two recombinant plasmids were obtained. Only one of these plasmids (STM1-A) conferred the selective fluoroquinolone resistance phenotype to E. coli DH5α. The chromosomal insert from STM1-A, digested with EcoRI and HindIII restriction endonucleases, produced two DNA fragments and these were cloned separately into pUC19 thereby generating two new plasmids, STM1-A1 and STM1-A2. Only STM1-A1 conferred the selective fluoroquinolone resistance phenotype to E. coli DH5α. Sequence and subcloning analyses of STM1-A1 showed the presence of an intact RecA open reading frame. Unlike that of the wild-type E. coli DH5α, protein analysis of a crude STM1-A1 extract showed overexpression of a 40 kDa protein. Western blotting confirmed the 40 kDa protein band to be RecA. When a RecA PCR product was cloned into pGEM-T and introduced into E. coli DH5α, the STM1-A11 subclone retained fluoroquinolone resistance. These results suggest that overexpression of RecA causes selective fluoroquinolone resistance in E. coli DH5α.
Descritores: Farmacorresistência Bacteriana/efeitos dos fármacos
Escherichia coli
Fluoroquinolonas/farmacologia
Recombinases Rec A/genética
Salmonella enterica
Sorogrupo
-Western Blotting
Clonagem Molecular
DNA Girase/efeitos dos fármacos
Escherichia coli/classificação
Escherichia coli/efeitos dos fármacos
Escherichia coli/metabolismo
Biblioteca Genômica
INHIBITORY CONCENTRATION ACADEMIES AND INSTITUTES
Testes de Sensibilidade Microbiana
Fases de Leitura Aberta/genética
Reação em Cadeia da Polimerase
Fatores R/metabolismo
Salmonella enterica/classificação
Salmonella enterica/efeitos dos fármacos
Salmonella enterica/genética
Tipo de Publ: Research Support, Non-U.S. Gov't
Responsável: BR1.1 - BIREME


  2 / 7 LILACS  
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Id: lil-659650
Autor: Galvão, C.W.; Souza, E.M.; Etto, R.M.; Pedrosa, F.O.; Chubatsu, L.S.; Yates, M.G.; Schumacher, J.; Buck, M.; Steffens, M.B.R..
Título: The RecX protein interacts with the RecA protein and modulates its activity in Herbaspirillum seropedicae
Fonte: Braz. j. med. biol. res = Rev. bras. pesqui. méd. biol;45(12):1127-1134, Dec. 2012. ilus.
Idioma: en.
Resumo: DNA repair is crucial to the survival of all organisms. The bacterial RecA protein is a central component in the SOS response and in recombinational and SOS DNA repairs. The RecX protein has been characterized as a negative modulator of RecA activity in many bacteria. The recA and recX genes of Herbaspirillum seropedicae constitute a single operon, and evidence suggests that RecX participates in SOS repair. In the present study, we show that the H. seropedicae RecX protein (RecX Hs) can interact with the H. seropedicaeRecA protein (RecA Hs) and that RecA Hs possesses ATP binding, ATP hydrolyzing and DNA strand exchange activities. RecX Hs inhibited 90% of the RecA Hs DNA strand exchange activity even when present in a 50-fold lower molar concentration than RecA Hs. RecA Hs ATP binding was not affected by the addition of RecX, but the ATPase activity was reduced. When RecX Hs was present before the formation of RecA filaments (RecA-ssDNA), inhibition of ATPase activity was substantially reduced and excess ssDNA also partially suppressed this inhibition. The results suggest that the RecX Hs protein negatively modulates the RecA Hs activities by protein-protein interactions and also by DNA-protein interactions.
Descritores: Proteínas de Bactérias/metabolismo
Herbaspirillum/química
Recombinases Rec A/metabolismo
-DNA Bacteriano
Escherichia coli/metabolismo
Ligação Proteica
Tipo de Publ: Research Support, Non-U.S. Gov't
Responsável: BR1.1 - BIREME


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Id: lil-634687
Autor: Oderiz, Sebastián; Palau, María J.; Del Palacio, Paula; Lewis, Miriam C; Bettiol, Marisa P; Martina, Pablo; Bosch, Alejandra; Yantorno, Osvaldo M; Gatti, Blanca M.
Título: Evaluación de los sistemas comerciales automatizados VITEK 2 y API 20NE para la identificación de organismos del complejo Burkholderia cepacia aislados de muestras clínicas / Evaluation of commercial systems VITEK 2 and API 20NE for identification of Burkholderia cepacia complex bacteria from clinical samples
Fonte: Rev. argent. microbiol;43(3):168-175, jun.-set. 2011. ilus, tab.
Idioma: es.
Resumo: Las especies del complejo Burkholderia cepacia (CBC) son capaces de causar infecciones crónicas del tracto respiratorio en pacientes con fibrosis quística y en otros individuos inmunocomprometidos. La mayoría de estas especies exhiben alta resistencia a la terapia antibiótica, lo que genera la necesidad de una detección rápida y precisa para poder implementar estrategias de control adecuadas. En este trabajo se utilizó la técnica de reacción en cadena de la polimerasa (PCR) para amplificar el gen recA (PCR-recA), con el fin de identificar microorganismos pertenecientes al CBC. Con este método molecular como referencia, se evaluó la sensibilidad (S) y la especificidad (E) de dos sistemas de identificación comerciales automatizados, VITEK 2 y API 20NE (bioMérieux®), así como también el valor de las pruebas bioquímicas manuales más representativas para la identificación de estos microorganismos. El método VITEK 2 presentó una S del 71,1 % y una E del 100 %; para el método API 20NE, estos valores fueron 69,7 % y 90,2 %, respectivamente. En cuanto a las pruebas fenotípicas manuales, los resultados obtenidos fueron más heterogéneos, lo que posiblemente se deba a que estas bacterias podrían sufrir presión selectiva para sobrevivir en pacientes crónicos y perder factores fenotípicos característicos. La técnica de PCR-recA resultó de fácil implementación, por lo que cabe considerar a esta técnica de identificación como una opción viable, aun en laboratorios de diagnóstico clínico de mediana complejidad.

Species belonging to the Burkholderia cepacia complex (BCC) are capable of causing chronic respiratory tract infections in patients suffering from cystic fibrosis as wel as in immunocompromised individuals. Most of these species are highly resistant to antibiotic therapy, generating the need for their rapid and accurate detection for the proper treatment and clinical management of these patients. In this wok, the polymerase chain reaction (PCR) technique based on the amplification of the recA gene (PCR-recA) was applied for an accurate identification of bacteria belonging to the BCC. Sensitivity (S) and specificity (E) of two biochemically-based commercial automated systems, API 20NE and VITEK 2 (bioMérieux®), and of the most representative biochemical manual tests for the identification of the Burkholderia cepacia complex were herein evaluated. The commercial systems VITEK 2 and API 20NE showed the following sensitivity and specificity vaues for identification to the species level, S: 71.1 %, E: 100 %, S: 69.7 %, E: 90.2 %, respectively. More complex results were observed for phenotypic manual tests, since BCC bacteria can undergo selective pressure to survive in chronic patients causing the loss of their typical phenotypic characteristics. The PCR-recA technique was easy to implement even in medium-complexity clinical diagnostic laboratories.
Descritores: Técnicas de Tipagem Bacteriana/métodos
Infecções por Burkholderia/microbiologia
Complexo Burkholderia cepacia/isolamento & purificação
Kit de Reagentes para Diagnóstico
Infecções Respiratórias/microbiologia
-Automação
Proteínas de Bactérias/genética
Infecções por Burkholderia/diagnóstico
Infecções por Burkholderia/etiologia
Colorimetria/métodos
Fibrose Cística/complicações
Suscetibilidade a Doenças
DNA Bacteriano/genética
Genes Bacterianos
Genótipo
Reação em Cadeia da Polimerase/métodos
Padrões de Referência
Reprodutibilidade dos Testes
Recombinases Rec A/genética
Infecções Respiratórias/diagnóstico
Infecções Respiratórias/etiologia
Sensibilidade e Especificidade
Software
Limites: Humanos
Tipo de Publ: Estudo Comparativo
Estudo de Avaliação
Responsável: AR1.2 - Instituto de Investigaciónes Epidemiológicas


  4 / 7 LILACS  
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Id: lil-417595
Autor: Miyoshi, A; Rochat, T; Gratadoux, J. J; Le Loir, Y; Oliveira, S. C; Langella, P; Azevedo, V.
Título: Oxidative stress in Lactococcus lactis
Fonte: Genet. mol. res. (Online);2(4):348-359, Dec. 2003.
Idioma: en.
Resumo: Lactococcus lactis, the most extensively characterized lactic acid bacterium, is a mesophilic- and microaerophilic-fermenting microorganism widely used for the production of fermented food products. During industrial processes, L. lactis is often exposed to multiple environmental stresses (low and high temperature, low pH, high osmotic pressure, nutrient starvation and oxidation) that can cause loss or reduction of bacterial viability, reproducibility, as well as organoleptic and/or fermentative qualities. Among these stress factors, oxidation can be considered one of the most deleterious to the cell, causing cellular damage at both molecular and metabolic levels. During the last two decades, considerable efforts have been made to improve our knowledge of oxidative stress in L. lactis. Many genes involved with both oxidative stress resistance and control mechanisms have been identified; functionally they seem to overlap. The finding of new genes, and a better understanding of the molecular mechanisms of stress resistance in L. lactis and other lactic acid bacterium, will lead to the construction and isolation of stress-resistant strains. Such strains could be exploited for both traditional and probiotic uses
Descritores: Estresse Oxidativo/fisiologia
Lactococcus lactis/metabolismo
-Complexos Multienzimáticos/metabolismo
Estresse Oxidativo/genética
Genes Bacterianos/genética
Lactococcus lactis/genética
NADH NADPH Oxirredutases/metabolismo
Peroxidases/metabolismo
Recombinases Rec A/metabolismo
Sobrevivência Celular/genética
Superóxido Dismutase/metabolismo
Tipo de Publ: Research Support, U.S. Gov't, Non-P.H.S.
Responsável: BR1.1 - BIREME


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Id: lil-345973
Autor: Morais Junior, Marcos Antonio de; Santos, José Ferreira dos; Henriques, João Antonio Pegas.
Título: Expression of the bacterial recA gene impairs genetic recombination and sporulation in a Saccharomyces cerevisiae diploid strain
Fonte: Genet. mol. biol;26(2):213-220, Jun. 2003. tab, graf.
Idioma: en.
Resumo: The Escherichia coli RecA protein (RecAp) has been demonstrated to induce mutagenesis in yeast cells, although there is still little information on the role of the RecAp in yeast recombination events. We evaluated spontaneous and induced general recombination in vegetative and meiotic cells of the XS2316 strain of the yeast Saccharomyces cerevisiae bearing the recA gene. We found that RecAp decreased reciprocal recombination, gene conversion and intrachromosomal recombination and promoted an increase in error-prone processes in both vegetative and meiotic cells, while its negative effect on meiotic recombination blocked ascospore formation
Descritores: Recombinases Rec A
Recombinação Genética
Reparo do DNA
Saccharomyces cerevisiae
-Esporos Fúngicos
Responsável: BR26.1 - Biblioteca Central


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Id: lil-302377
Autor: Fuentes Lorenzo, Jorge L.
Título: Respuesta SOS en E Coli: test de inducción de genes SOS como ensayo de mutagenicidad / SOS response in E Coli: induction test of SOS genes as a mutagenecity assay
Fonte: Rev. cuba. invest. bioméd;18(1):5-9, ene.-abr. 1999.
Idioma: es.
Resumo: Se presentan las particularidades de la respuesta SOS en células de E. coli y se realiza una descripción de los tipos de daños que inducen dicha respuesta. Se tratan además los aspectos relacionados con la regulación del circuito RecA/Lex A, así como de la señal inductora de la respuesta. Se resumen, de acuerdo con la bibliografía actualizada del tema, las funciones de los principales productos génicos de esta respuesta, en particular, RecA y UmuC y D, durante la restauración de la replicación y se discute un modelo que explica el fenómeno de la mutagénesis SOS en E. coli. Se hacen algunas consideraciones evolutivas de la mutagénesis SOS en bacterias de acuerdo con el modelo cairsiano de evolución. Se explican las particularidades de los tests de inducción de genes SOS, así como su utilidad, tanto en la evaluación de efectos genotóxicos como en la prospección y estudio de mecanismos de acción de sustancias antimutagénicas, radioprotectoras, o ambas.
Descritores: Replicação do DNA
DNA Bacteriano
Escherichia coli
Regulação Bacteriana da Expressão Gênica
Mutagênese
Recombinases Rec A/genética
Proteínas de Bactérias/genética
Resposta SOS em Genética
Responsável: CU1.1 - Biblioteca Médica Nacional


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Id: lil-152618
Autor: Lage, C; Leitäo, A. C.
Título: Membrane permeability and sensitivity to lethal heat are affected by lexA and recA mutations in Escherichia coli K12
Fonte: Braz. j. med. biol. res = Rev. bras. pesqui. méd. biol;27(10):2383-9, Oct. 1994. tab, graf.
Idioma: en.
Conferência: Apresentado em: Annual Meeting of the Federaçäo of the Sociedades de Biologia Experimental, 9, Caxambu, Aug. 24-27, 1994.
Resumo: Membrane permeability was evaluated in several SOS-deficient strains. Great heat sensitivity was observed in all the lexA (Ind-) strains, which was associated to an increase in membrane permeability (up to 120 per cent increase above the wild-type control), as assayed by the crystal violet (CV) growth inhibition. After irradiation with a single UV dose (75 J.m-2 delivered to wild-type and 2 J.m-2 to the lex A3 strain), survival was followed by plating cells in both nutrient and membrane permeability-selective (nutrient + CV) media and a great lethality due to CV was observed in a lexA mutant, which appeared to be about 100 times more sensitive to CV compared to its wild-type parent stain. The decreased membrane integrity found in the lex A-deficient strains suggests that LexA protein and/or LexA-repressed genes may interact with the bacterial membrane, which could be the location of SOS events
Descritores: Permeabilidade da Membrana Celular
Escherichia coli/efeitos da radiação
-Violeta Genciana
Mutação
Recombinases Rec A/farmacologia
Sensibilidade e Especificidade
Resposta SOS em Genética
Responsável: BR1.1 - BIREME



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