RESUMEN
Shewanella oneidensis is an important model organism for bioremediation studies because of its diverse respiratory capabilities, conferred in part by multicomponent, branched electron transport systems. Here we report the sequencing of the S. oneidensis genome, which consists of a 4,969,803-base pair circular chromosome with 4,758 predicted protein-encoding open reading frames (CDS) and a 161,613-base pair plasmid with 173 CDSs. We identified the first Shewanella lambda-like phage, providing a potential tool for further genome engineering. Genome analysis revealed 39 c-type cytochromes, including 32 previously unidentified in S. oneidensis, and a novel periplasmic [Fe] hydrogenase, which are integral members of the electron transport system. This genome sequence represents a critical step in the elucidation of the pathways for reduction (and bioremediation) of pollutants such as uranium (U) and chromium (Cr), and offers a starting point for defining this organism's complex electron transport systems and metal ion-reducing capabilities.
Asunto(s)
Regulación Bacteriana de la Expresión Génica , Genoma Bacteriano , Análisis de Secuencia de ADN , Análisis de Secuencia de Proteína , Shewanella/genética , Shewanella/metabolismo , Secuencia de Aminoácidos , Biodegradación Ambiental , Respiración de la Célula , Transporte de Electrón , Expresión Génica , Metales/metabolismo , Datos de Secuencia Molecular , Sistemas de Lectura Abierta/genética , Compuestos Orgánicos/metabolismo , Oxidación-Reducción , Plásmidos , Proteómica/métodos , Alineación de Secuencia/métodos , Shewanella/clasificación , Shewanella/patogenicidad , Especificidad de la Especie , Contaminantes Químicos del Agua/metabolismo , Purificación del Agua/métodosRESUMEN
Dehalococcoides ethenogenes is the only bacterium known to reductively dechlorinate the groundwater pollutants, tetrachloroethene (PCE) and trichloroethene, to ethene. Its 1,469,720-base pair chromosome contains large dynamic duplicated regions and integrated elements. Genes encoding 17 putative reductive dehalogenases, nearly all of which were adjacent to genes for transcription regulators, and five hydrogenase complexes were identified. These findings, plus a limited repertoire of other metabolic modes, indicate that D. ethenogenes is highly evolved to utilize halogenated organic compounds and H2. Diversification of reductive dehalogenase functions appears to have been mediated by recent genetic exchange and amplification. Genome analysis provides insights into the organism's complex nutrient requirements and suggests that an ancestor was a nitrogen-fixing autotroph.