RESUMEN
Development of the human gut microbiota commences at birth, with bifidobacteria being among the first colonizers of the sterile newborn gastrointestinal tract. To date, the genetic basis of Bifidobacterium colonization and persistence remains poorly understood. Transcriptome analysis of the Bifidobacterium breve UCC2003 2.42-Mb genome in a murine colonization model revealed differential expression of a type IVb tight adherence (Tad) pilus-encoding gene cluster designated "tad(2003)." Mutational analysis demonstrated that the tad(2003) gene cluster is essential for efficient in vivo murine gut colonization, and immunogold transmission electron microscopy confirmed the presence of Tad pili at the poles of B. breve UCC2003 cells. Conservation of the Tad pilus-encoding locus among other B. breve strains and among sequenced Bifidobacterium genomes supports the notion of a ubiquitous pili-mediated host colonization and persistence mechanism for bifidobacteria.
Asunto(s)
Bifidobacterium/genética , Bifidobacterium/fisiología , Fimbrias Bacterianas/genética , Fimbrias Bacterianas/fisiología , Genoma Bacteriano , Secuencia de Aminoácidos , Animales , Proteínas Bacterianas/genética , Proteínas Bacterianas/fisiología , Secuencia de Bases , Bifidobacterium/crecimiento & desarrollo , Bifidobacterium/ultraestructura , Hibridación Genómica Comparativa , ADN Bacteriano/genética , Femenino , Fimbrias Bacterianas/ultraestructura , Tracto Gastrointestinal/microbiología , Regulación Bacteriana de la Expresión Génica , Vida Libre de Gérmenes , Humanos , Masculino , Metagenoma , Ratones , Ratones Endogámicos BALB C , Microscopía Electrónica de Transmisión , Microscopía Inmunoelectrónica , Datos de Secuencia Molecular , Familia de Multigenes , Mutación , Homología de Secuencia de AminoácidoRESUMEN
The Clustal programs are widely used for carrying out automatic multiple alignment of nucleotide or amino acid sequences. The most familiar version is ClustalW, which uses a simple text menu system that is portable to more or less all computer systems. ClustalX features a graphical user interface and some powerful graphical utilities for aiding the interpretation of alignments and is the preferred version for interactive usage. Users may run Clustal remotely from several sites using the Web or the programs may be downloaded and run locally on PCs, Macintosh, or Unix computers. The protocols in this unit discuss how to use ClustalX and ClustalW to construct an alignment, and create profile alignments by merging existing alignments.