Base de dados : LILACS
Pesquisa : B03.510.024.049.525.500.720.662 [Categoria DeCS]
Referências encontradas : 8 [refinar]
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Id: biblio-828168
Autor: Pal, Rahul; Hameed, Saif; Sharma, Sharda; Fatima, Zeeshan.
Título: Influence of iron deprivation on virulence traits of mycobacteria
Fonte: Braz. j. infect. dis;20(6):585-591, Nov.-Dec. 2016. graf.
Idioma: en.
Resumo: ABSTRACT Novel strategies to combat the ever increasing burden of drug resistance in Mycobacterium tuberculosis (MTB) causing tuberculosis (TB) remains a global concern. The ability of MTB to sense and adapt to restricted iron conditions in the hostile environment is essential for their survival and confers the basis of their success as dreadful pathogen. The striking and clinically relevant virulence trait of MTB is its ability to form biofilms and adhere to the host cells. The present study elucidated the effect of iron deprivation on biofilm formation and cell adherence of Mycobacterium smegmatis, a non-pathogenic surrogate of MTB. Firstly, we showed that iron deprivation leads to enhanced cell sedimentation rate and altered colony morphology depicting alterations in cell surface envelope properties. We explored that biofilm formation and cell adherence to polystyrene surface as well as human oral epithelial cells were considerably reduced under iron deprivation both in presence of 2,2 BP (iron chelator) and siderophore mutant Δ011-14 strain. We further investigated that the potency of three first line anti-TB drugs (Isoniazid, Ethambutol, Rifampicin) to inhibit both biofilm formation and cell adhesion were enhanced under iron deprivation in contrast to the drugs when tested alone. Taken together, by virtue of the indispensability of iron for functional virulence traits in mycobacteria, iron deprivation strategies could be further exploited against this notorious human pathogen to explore novel drug targets.
Descritores: Virulência
Aderência Bacteriana/efeitos dos fármacos
Biofilmes/crescimento & desenvolvimento
Mycobacterium smegmatis/patogenicidade
Células Epiteliais/microbiologia
Ferro/farmacologia
-Biofilmes/efeitos dos fármacos
Limites: Humanos
Responsável: BR1.1 - BIREME


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Id: biblio-878893
Autor: Figueroa Reyes, Luis Alberto.
Título: Determinación de la actividad contra Mycobacterium smegmatis y Mycobacterium tuberculosis de extractos de plantas de uso medicinal en Guatemala / Determination of the activity against Mycobacterium smegmatis and Mycobacterium tuberculosis of plant extracts for medicinal use in Guatemala.
Fonte: Guatemala; s.n; 2000. 86 p. tab.
Idioma: es.
Tese: Apresentada a Universidad de San Carlos de Guatemala para obtenção do grau de Especialista.
Resumo: El presente estudio se llevó a cabo la determinación de la actividad inhibidora contra Mycobacterium smegmatis y Mycobacterium tuberculosis de extracto de plantas de uso medicinal en Guatemala. El propósito de este estudio fue determinar si existía correlación entre la acción inhibidora in vitro de extractos hexánicos, clorosfórmico, metanólicos y acuosos de las plantas: Sida acuta, Enterolobium cyclocarpum, Piper auritum, Stachytarpheta cayennensis y Ocimum micranthum, de una cepa de Mycobacterium smegmatis y una cepa multisensible, 3 de mediana resistencia y una multiresistencia y una multiresistencia de Mycobacterium tuberculosis.
Descritores: Mycobacterium
Mycobacterium smegmatis
Extratos Vegetais
-Guatemala
Técnicas In Vitro
Limites: Humanos
Responsável: BR1.1 - BIREME


  3 / 8 LILACS  
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Id: lil-778999
Autor: Oliveira, Fábio Muniz de; Trentini, Monalisa Martins; Junqueira-Kipnis, Ana Paula; Kipnis, André.
Título: The mc2-CMX vaccine induces an enhanced immune response against Mycobacterium tuberculosis compared to Bacillus Calmette-Guérin but with similar lung inflammatory effects
Fonte: Mem. Inst. Oswaldo Cruz;111(4):223-231, Apr. 2016. graf.
Idioma: en.
Resumo: Although the attenuated Mycobacterium bovis Bacillus Calmette-Guérin (BCG) vaccine has been used since 1921, tuberculosis (TB) control still proceeds at a slow pace. The main reason is the variable efficacy of BCG protection against TB among adults, which ranges from 0-80%. Subsequently, the mc2-CMX vaccine was developed with promising results. Nonetheless, this recombinant vaccine needs to be compared to the standard BCG vaccine. The objective of this study was to evaluate the immune response induced by mc2-CMX and compare it to the response generated by BCG. BALB/c mice were immunised with both vaccines and challenged withMycobacterium tuberculosis (Mtb). The immune and inflammatory responses were evaluated by ELISA, flow cytometry, and histopathology. Mice vaccinated with mc2-CMX and challenged with Mtb induced an increase in the IgG1 and IgG2 levels against CMX as well as recalled specific CD4+ T-cells that produced T-helper 1 cytokines in the lungs and spleen compared with BCG vaccinated and challenged mice. Both vaccines reduced the lung inflammatory pathology induced by the Mtb infection. The mc2-CMX vaccine induces a humoral and cellular response that is superior to BCG and is efficiently recalled after challenge with Mtb, although both vaccines induced similar inflammatory reductions.
Descritores: Vacina BCG/imunologia
Mycobacterium bovis/imunologia
Mycobacterium smegmatis/imunologia
Mycobacterium tuberculosis/imunologia
Tuberculose Pulmonar/imunologia
-Antígenos de Bactérias
Modelos Animais de Doenças
Pulmão/efeitos dos fármacos
Camundongos
Camundongos Endogâmicos BALB C
Tuberculose Pulmonar/patologia
Tuberculose Pulmonar/prevenção & controle
Vacinas Sintéticas/imunologia
Limites: Animais
Ratos
Responsável: BR1.1 - BIREME


  4 / 8 LILACS  
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Teixeira, Maria Francisca Simas
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Id: lil-478874
Autor: Carneiro, Ana Lúcia Basílio; Teixeira, Maria Francisca Simas; Oliveira, Viviana Maria Araújo de; Fernandes, Ormezinda Celeste Cristo; Cauper, Gláucia Socorro de Barros; Pohlit, Adrian Martin.
Título: Screening of Amazonian plants from the Adolpho Ducke forest reserve, Manaus, state of Amazonas, Brazil, for antimicrobial activity
Fonte: Mem. Inst. Oswaldo Cruz;103(1):31-38, Feb. 2008. tab.
Idioma: en.
Projeto: CNPq; . MCT. INPA.
Resumo: Tropical forests are species-rich reserves for the discovery and development of antimicrobial drugs. The aim of this work is to investigate the in vitro antimicrobial potential of Amazon plants found within the National Institute on Amazon Research's Adolpho Ducke forest reserve, located in Manaus, state of Amazonas, Brazil. 75 methanol, chloroform and water extracts representing 12 plant species were tested for antimicrobial activity towards strains of Mycobacterium smegmatis, Escherichia coli, Streptococcus sanguis, Streptococcus oralis, Staphylococcus aureus and Candida albicans using the gel-diffusion method. Active extracts were further evaluated to establish minimum inhibitory concentrations (MIC) and antimicrobial profiles using bioautography on normal-phase thin-layer chromatography plates. Diclinanona calycina presented extracts with good antimicrobial activity and S. oralis and M. smegmatis were the most sensitive bacteria. D. calycina and Lacmellea gracilis presented extracts with the lowest MIC (48.8 µg/ml). D. calycina methanol and chloroform leaf extracts presented the best overall antimicrobial activity. All test organisms were sensitive to D. calycina branch chloroform extract in the bioautography assay. This is the first evaluation of the biological activity of these plant species and significant in vitro antimicrobial activity was detected in extracts and components from two species, D. calycina and L. gracilis.
Descritores: Antibacterianos/farmacologia
Candida albicans/efeitos dos fármacos
Bactérias Gram-Negativas/efeitos dos fármacos
Bactérias Gram-Positivas/efeitos dos fármacos
Extratos Vegetais/farmacologia
Plantas Medicinais/química
-Brasil
Conservação dos Recursos Naturais
Escherichia coli/efeitos dos fármacos
Imunodifusão
Testes de Sensibilidade Microbiana
Mycobacterium smegmatis/efeitos dos fármacos
Plantas Medicinais/classificação
Staphylococcus aureus/efeitos dos fármacos
Streptococcus/efeitos dos fármacos
Árvores
Limites: Humanos
Tipo de Publ: Research Support, Non-U.S. Gov't
Responsável: BR1.1 - BIREME


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Id: lil-362063
Autor: Arráiz, Nailet; Salazar, L; Takiff, H.
Título: Condiciones ambientales que afectan la expresiín del gen suoM: un factor sigma de estrés en M. smegmatis / Environment conditions affect the expression of the suoM gene: an stress sigma factor in M. smegmatis
Fonte: Kasmera;30(2):101-111, dic. 2002. ilus, tab, graf.
Idioma: es.
Resumo: Los factores sigmas se asocian a la ARN polimerasa y le confieren especificidad de reconocimiento de regiones promotoras. Esto provee un nivel de regulación transcripcional, que determina que un grupo de genes sea expresado de acuerdo a las necesidades fisiológicas de la célula bacteriana. El análisis de secuencia de la región del origen de replicación de Mycobacterium smegmatis reveló la presencia de un marco de lectura con capacidad codificante para un sigma de la subfamilia ECF (extracytoplasmic function), los cuales se carcaterizan por dirigir la transcripción de genes en respuesta a cambios en las condiciones ambientales. Con el objeto de identificar las condiciones ambientales que estimulan la expresión del gen aislado, designado suoM (sigma unido al origen en microbacterias), se contruyeron fusiones transcripcionales PsuoM-lacZ' sobre el plásmido de fusión de operones pJEM15. Las construcciones se introdujeron por electroporación en M.smegmatis y las células transformadas se sometieron a varias condiciones de estrés ambiental a fin de estudiar la actividad promotora del gen suoM mediante ensayos ß-galactosidasa. Se observó un incremento de 2,0-3,5 veces en la actividad promotora, al transferir las células a 45°C y cuando el cultivo alcanza fase estacionaria de crecimiento. Los resultados sugieren que suoM podría estar involucrado en la regulación de la expresión de genes en condiciones de elevada temperatura y en fase estacionaria de crecimiento, condiciones inductoras que podrían tener algún significado en el potencial patogénico de micobacterias y en la habilidad de M.tuberculosis para causar infección latente.
Descritores: Meio Ambiente
Genes
Mycobacterium smegmatis
Fator sigma
Estresse Fisiológico
-Medicina
Venezuela
Tipo de Publ: Relatos de Casos
Responsável: VE1.1 - Biblioteca Humberto Garcia Arocha


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Id: lil-305351
Autor: Recht, Judith; Martínez, Asunción; Torello, Sandra; Kolter, Roberto.
Título: Movilidad por deslizamiento y formación de biofilms en las micobacterias / Sliding mobility and biofilm formation in mycobacterium
Fonte: Acta cient. venez;52(supl.1):45-49, 2001. graf.
Idioma: es.
Resumo: Usando como modelo Mycobacterium smegmatis, un organismo no movil, hemos estudiado por primera vez en una especie micobacteriana el fenómeno llamado" deslizamiento" o sliding motility, así como la formación de biofilms. Para ello se realizó un screen de mutantes con la finalidad de identificar los genes necesarios para el deslizamiento sobre placas de mivilidad. El análisis genético aquí descrito ha sido publicado recientemente. Los genes requeridos tanto para deslizamiento como para la formación de biofilms (mps y tmtpC) están relacionados con el proceso de biosíntesis y transporte de los glicopeptidolípidos (GPLs) a la cápsula de las micobacterias. En base a nuestros resultados proponemos un modelo para el papel que juegan los GPLs en ambos fenómenos
Descritores: Biofilmes/crescimento & desenvolvimento
Biofilmes/crescimento & desenvolvimento
Mycobacterium smegmatis/genética
-Modelos Biológicos
Venezuela
Limites: Humanos
Masculino
Feminino
Tipo de Publ: Revisão
Responsável: VE1.1 - Biblioteca Humberto Garcia Arocha


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Id: lil-305349
Autor: Arráiz, Nailet; Salazar, Leiria; López, Gustavo; Rodríguez, Rosalba; Casart, Yveth; Takiff, Howard.
Título: Caracterización de la expresión y función sigM de un factor sigma ECF en micobacterias / Characterization of the expression and function sigM of an ECF sigma factor in mycobacteriums
Fonte: Acta cient. venez;52(supl.1):40-41, 2001.
Idioma: es.
Resumo: La supervivencia del bacilo Micobacteria tuberculosis dentro del macrófago depende de su capacidad de responder al stress oxidativa, y los factores sigma, subfamilia ECF, probablemente tienen un rol importante. Investigamos un factor sigma, sigM, cuyos gen se encuentran cerca del origen de replicación. Tanto en M.smegmatis como en M.bovis BCG, la expresión del gen esta inducida en temperaturas altas y en fase estacionaria. Cepas de M.smegmatis sin una copia activa de sigM muestran un defecto en la supervivencia en el stress oxidativo y también en la inducción de la actividad de thioredoxina reductasa, que reduce puentes disulfuricos formado en stress oxidativo. Estos datos sugieren que SigM regula los tioredoxinas y constituye parte de unas respuestas protectivas muy complejos de la bacteria
Descritores: Micobactérias não Tuberculosas
Mycobacterium smegmatis
Mycobacterium tuberculosis
Estresse Oxidativo
Fator sigma
-Medicina
Ciência
Venezuela
Limites: Humanos
Masculino
Feminino
Tipo de Publ: Revisão
Responsável: VE1.1 - Biblioteca Humberto Garcia Arocha


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Id: lil-226209
Autor: Bigi, F; Taboga, O; Romano, M. I; Alito, A; Fisanotti, J. C; Cataldi, A. A.
Título: Expression of the Mycobacterium bovis P36 gene in Mycobacterium smegmatis and the baculovirus/insect cell system
Fonte: Braz. j. med. biol. res = Rev. bras. pesqui. méd. biol;32(1):29-37, Jan. 1999. ilus, tab.
Idioma: en.
Resumo: In the present study we evaluated different systems for the expression of mycobacterial antigen P36 secreted by Mycobacterium bovis. P36 was detected by Western blot using a specific antiserum. The P36 gene was initially expressed in E. coli, under the control of the T7 promoter, but severe proteolysis prevented its purification. We then tried to express P36 in M. smegmatis and insect cells. For M. smegmatis, we used three different plasmid vectors differing in copy number and in the presence of a promoter for expression of heterologous proteins. P36 was detected in the cell extract and culture supernatant in both expression systems and was recognized by sera from M. bovis-infected cattle. To compare the expression level and compartmentalization, the MPB70 antigen was also expressed. The highest production was reached in insect cell supernatants. In conclusion, M. smegmatis and especially the baculovirus expression system are good choices for the production of proteins from pathogenic mycobacteria for the development of mycobacterial vaccines and diagnostic reagents
Descritores: Antígenos de Bactérias/genética
Proteínas de Bactérias
Baculoviridae/genética
Clonagem Molecular
Escherichia coli/citologia
Expressão Gênica/genética
Mycobacterium bovis/genética
Mycobacterium smegmatis/genética
-Western Blotting
Extratos Celulares
Limites: Animais
Bovinos
Tipo de Publ: Estudo Comparativo
Research Support, Non-U.S. Gov't
Responsável: BR1.1 - BIREME



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