856 research outputs found

    Functional consequences of mutations in CDKL5, an X-linked gene involved in infantile spasms and mental retardation

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    Mutations in the X-linked cyclin-dependent kinase-like 5 (CDKL5) gene have been identified in patients with Rett syndrome, West syndrome, and X-linked infantile spasms sharing the common features of generally intractable early seizures and mental retardation. Disease-causing mutations are distributed in both the catalytic domain and in the large COOH terminus. In this report, we examine the functional consequences of some Rett mutations of CDKL5 together with some synthetically designed derivatives useful to underline the functional domains of the protein. The mutated CDKL5 derivatives have been subjected to in vitro kinase assays and analyzed for phosphorylation of the TEY (Thr-Glu-Tyr) motif within the activation loop, their subcellular localization, and the capacity of CDKL5 to interact with itself. Whereas wild-type CDKL5 autophosphorylates and mediates the phosphorylation of the methyl-CpG-binding protein 2 (MeCP2) in vitro, Rett-mutated proteins show both impaired and increased catalytic activity suggesting that a tight regulation of CDKL5 is required for correct brain functions. Furthermore, we show that CDKL5 can self-associate and mediate the phosphorylation of its own TEY (Thr-Glu-Tyr) motif. Eventually, we show that the COOH terminus regulates CDKL5 properties; in particular, it negatively influences the catalytic activity and is required for its proper sub-nuclear localization. We propose a model in which CDKL5 phosphorylation is required for its entrance into the nucleus whereas a portion of the COOH-terminal domain is responsible for a stable residency in this cellular compartment probably through protein-protein interactions

    Severe diarrhea outbreak in beef calves (Bos indicus) caused by G6P[11], an emergent genotype of bovine rotavirus group A

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    The episodes of diarrhea caused by neonatal bovine rotavirus group A (BoRVA) constitute one of the major health problems in the calf rearing worldwide. The main G (VP7) and P (VP4) genotypes of BoRVA strains involved in the etiology of diarrhea in calves are G6P[1], G10P[11], G6P[5], and G8P[1]. However, less frequently, other G and P genotypes have been described in BoRVA strains identified in diarrheic fecal samples of calves. This study describes the identification and molecular characterization of an emerging genotype (G6P[11]) in BoRVA strains involved in the etiology of a diarrhea outbreak in beef calves in a cattle herd of high production in extensive management system. The diarrhea outbreak, which showed high morbidity (60%) and lethality (7%) rates, occurred in calves (n= 384) Nelore (Bos indicus) up to 30-day-old from the State of Mato Grosso do Sul, Brazil. BoRVA was identified in 80% (16/20) of the fecal samples analyzed by polyacrylamide gel electrophoresis (PAGE) technique. In all PAGE-positive fecal samples were amplified products with 1,062-bp and 876-bp in the RT-PCR assays for VP7 (G type) and VP4 (VP8*) (P type) of BoRVA, respectively. The nucleotide sequence analysis of VP7 and VP4 genes of four wild-type BoRVA strains showed G6-III P[11]-III genotype/lineage. The G6P[11] genotype has been described in RVA strains of human and animal hosts, however, in calves this genotype was only identified in some cross-sectional studies and not as a single cause of diarrhea outbreaks in calves with high morbidity and lethality rates as described in this study. The monitoring of the G and P genotypes of BoRVA strains involved in diarrhea outbreaks in calves is important for both animal and public health by allowing the identification of the most frequent genotypes, the characterization of novel genotypes and to identify reassortments with genotypes described in animal and human hosts. The results of this study show the importance of the monitoring of the genotypes of BoRVA strains involved in episodes of bovine neonatal diarrhea as for characterization of frequency of occurrence and pathogenic potential of uncommon genotypes as for monitoring of the emergency of different BoRVA genotypes not included in commercial vaccines

    Escherichia coli O157:H7 Productor de toxina Shiga aisladas de muestras de agua relacionadas a Establecimientos pecuarios de engorde a corral

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    Recientemente han ocurrido brotes debido vegetales contaminados por Escherichia coli productor de toxina Shiga (stec). Estos productos frescos se contaminan a través del contacto directo de heces bovinas (abono), o indirectamente a través de irrigación con agua contaminada. Este estudio tuvo como objetivo establecer la prevalencia de stec O157:H7 en muestras de agua relacionadas a establecimientos pecuarios de engorde a corral (epec) de la provincia de Entre Ríos, Argentina, y su eventual relación con cepas vinculadas a enfermedad transmitida por alimentos. Usando como indicadores microbiológicos, coliformes, Escherichia coli, y anaerobios sufito-reductores, se estudió la eficiencia en el saneamiento de los efluentes de un epec que contaba con un sistema de lagunas sanitarias. Entre abril/2009 y julio/2011 se estudiaron 320 muestras de agua vinculadas a efluentes de 11 epec. Las cepas fueron caracterizadas feno-genotípicamente y subtipificadas por macrorrestricción y electroforesis de campo pulsado. Algunos de los perfiles identificados están incluidos en la base de datos nacional, correspondiendo a cepas obtenidas de casos de Síndrome Urémico Hemolítico, diarrea, muestras alimenticias y de origen animal. Los epec deben implementar estrategias de control con objeto de limitar el ingreso de stec en el medioambiente acuático. En el sistema de lagunas sanitarias estudiado se constató una franca disminución de los indicares utilizados pero insuficiente para eliminar su aporte al ambiente. La optimización de su funcionamiento es función de su mantenimiento, en especial la frecuente remoción de barros de las primeras piletas
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