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1.
Int. microbiol ; 16(2): 87-92, jun. 2013. ilus, tab
Artigo em Inglês | IBECS | ID: ibc-126423

RESUMO

Prc is a periplasmic protease involved in processing of penicillin-binding protein 3 (PBP3). Lack of Prc suppresses bile sensitivity in Dam-, Wec-, PhoP-, DamX-, and SeqA- mutants of Salmonella enterica, and increases bile resistance in the wild type. Changes in the activity of penicillin binding proteins PBP3, PBP4, PBP5/6 and PBP7 are detected in a Prc-background, suggesting that peptidogly can remodeling might contribute to bile resistance (AU)


No disponible


Assuntos
Humanos , Peptídeo Hidrolases/análise , Salmonella enterica/patogenicidade , Proteínas Periplásmicas/análise , Proteínas de Ligação às Penicilinas , Peptidoglicano
2.
Int. microbiol ; 15(1): 43-51, mar. 2012. ilus, tab
Artigo em Inglês | IBECS | ID: ibc-102991

RESUMO

Gram-positive bacteria of the genus Listeria contain many surface proteins covalently bound to the peptidoglycan. In the pathogenic species Listeria monocytogenes, some of these surface proteins mediate adhesion and entry into host cells. Specialized enzymes called sortases anchor these proteins to the cell wall by a mechanism involving processing and covalent linkage to the peptidoglycan. How bacteria coordinate the production of sortases and their respective protein substrates is currently unknown. The present work investigated whether the functional status of the sortase influences the level at which its cognate substrates are produced. The relative amounts of surface proteins containing an LPXTG sorting motif recognized by sortase A (StrA) were determined in isogenic wild-type and ΔsrtA strains of L. monocytogenes. The possibility of regulation at the transcriptional level was also examined. The results showed that the absence of SrtA did not affect the expression of any of the genes encoding LPXTG proteins. However, marked differences were found at the protein level for some substrates depending on the presence/absence of SrtA. In addition to the known «mis-sorting» of some LPXTG proteins caused by the absence of SrtA, the total amount of certain LPXTG protein species was lower in the ΔsrtA mutant. These data suggested that the rate of synthesis and/or the stability of a subset of LPXTG proteins could be regulated post-transcriptionally depending on the functionality of SrtA. For some LPXTG proteins, the absence of SrtA resulted in only a partial loss of the protein that remained bound to the peptidoglycan, thus providing support for additional modes of cell-wall association in some members of the LPXTG surface protein family (AU)


No disponible


Assuntos
Listeria monocytogenes/crescimento & desenvolvimento , Peptidoglicano/análise , Glicoproteínas de Membrana/análise , Regulação Bacteriana da Expressão Gênica , Frações Subcelulares , Western Blotting
3.
Enferm. infecc. microbiol. clín. (Ed. impr.) ; 26(10): 629-637, dic. 2008. ilus, tab
Artigo em Espanhol | IBECS | ID: ibc-60487

RESUMO

Chlamydophila pneumoniae es un patógeno humano intracelular, muy prevalente, con un ciclo único de desarrollo bifásico, que causa infecciones respiratorias en las vías altas y neumonía, y que actualmente se cree que puede ser un factor de riesgo para el desarrollo de la arteriosclerosis.C. pneumoniae muestra una gran complejidad en los antígenos de superficie de la membrana externa, ya sea por ser específicos pero poco inmunógenos (como la proteína principal de la membrana externa) o bien por ser muy inmunógenos pero poco específicos entre las especies de clamidias. Todo esto hace necesario profundizar en el estudio de nuevos antígenos que sean altamente inmunodominantes y específicos de especie. En este sentido, las proteínas polimórficas de la membrana externa (PMP) son a) específicas de clamidia, b) se exponen en la superficie de la bacteria y c) son muy inmunógenas, todo lo cual las hace acreedoras de un importante potencial de aplicación en los diferentes ensayos de laboratorio. Otras, como la proteína de choque térmico 60 (HSP 60), parecen estar relacionadas con la arteriosclerosis, por inducir un ataque inmunológico sobre la pared endotelial. A partir de los estudios existentes hasta la fecha, para obtener una conclusión sobre la relación entre la infección y la arteriosclerosis, faltan estudios con suficiente número de pacientes y muestras, prospectivo, comparativo frente a controles sanos, que utilicen la combinación de varias técnicas microbiológicas (directas e indirectas) en un mismo sujeto y muestra, relacionando los resultados con la actividad de la enfermedad (AU)


Chlamydophila pneumoniae is a highly prevalent intracellular human pathogen with a unique biphasic lifecycle. It is a common cause of upper respiratory infection and pneumonia, and is currently being studied as a potential risk factor for the development of atherosclerotic cardiovascular disease. The outer membrane surface antigens of C. pneumonia are highly complex: some, such as the major outer membrane protein, are specific, but poorly immunodominant, whereas others have stronger immunogenicity, but are cross-reactive among Chlamydia species. Therefore, new, highly immunodominant, species-specific antigens should be sought. In this regard, the polymorphic membrane proteins (PMPs) are a) unique to Chlamydiae, b) often exposed on the surface of the bacteria, and c) highly immunogenic; these factors make them potential candidates for application in laboratory assays. Other chlamydial antigens, such as heat shock protein (HSP) 60, have been associated with atherosclerotic lesions because of their ability to induce an immunological attack on the endothelial wall.Over the last decade, several studies have suggested apotential role of chronic C. pneumoniae infection in human atherosclerosis. Nevertheless, prospective studies with sufficiently large samples and a healthy comparison group, using a combination of direct and indirect microbiological techniques in the same subject and sample, are needed to establish a relationship between the infection and disease activity (AU)


Assuntos
Humanos , Chlamydophila pneumoniae/patogenicidade , Infecções por Chlamydophila/complicações , Arteriosclerose/microbiologia , Proteômica/métodos , Lipopolissacarídeos/isolamento & purificação , Proteínas da Membrana Bacteriana Externa/análise , Chaperonas Moleculares/análise , Peptidoglicano/análise
4.
Artigo em Espanhol | IBECS | ID: ibc-19786

RESUMO

Se revisan la estructura química, la farmacocinética, el espectro de actividad, los mecanismos de acción, las resistencias, las indicaciones y los efectos adversos de dos grupos de antibióticos: oxazolidinonas (linezolid) y glucopéptidos. Las oxazolidinonas inhiben la síntesis proteica y los glucopéptidos la síntesis de la pared bacteriana. Su espectro de actividad va dirigido fundamentalmente contra microorganismos grampositivos, incluidos los multirresistentes. Linezolid se absorbe el 100 por ciento y puede administrarse por vía oral o vía intravenosa; tiene un metabolismo mixto, por lo cual no es necesario ajustar la dosis en la insuficiencia renal o hepática moderadas. Los glucopéptidos no se absorben por vía oral y se eliminan por vía renal (ajustar dosis en insuficiencia renal). Sus principales indicaciones son las infecciones por grampositivos multirresistentes, siendo linezolid, además, eficaz frente a enterococos resistentes a los glucopéptidos. Linezolid puede causar trombopenia si la duración del tratamiento es superior a 2 semanas.El principal efecto secundario de vancomicina es su nefrotoxicidad, y teicoplanina puede causar fiebre (AU)


Assuntos
Humanos , Inibidores da Síntese de Proteínas , Oxazolidinonas , Anti-Infecciosos , Antibacterianos , Infecções Estafilocócicas , Vancomicina , Estrutura Molecular , Pneumonia Bacteriana , Infecções por Bactérias Gram-Positivas , Teicoplanina , Peptidoglicano , Farmacorresistência Bacteriana Múltipla , Biotransformação , Parede Celular , Acetamidas , Liberação de Histamina
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