87 research outputs found

    Genome Sequence of Fusobacterium nucleatum Subspecies Polymorphum — a Genetically Tractable Fusobacterium

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    Fusobacterium nucleatum is a prominent member of the oral microbiota and is a common cause of human infection. F. nucleatum includes five subspecies: polymorphum, nucleatum, vincentii, fusiforme, and animalis. F. nucleatum subsp. polymorphum ATCC 10953 has been well characterized phenotypically and, in contrast to previously sequenced strains, is amenable to gene transfer. We sequenced and annotated the 2,429,698 bp genome of F. nucleatum subsp. polymorphum ATCC 10953. Plasmid pFN3 from the strain was also sequenced and analyzed. When compared to the other two available fusobacterial genomes (F. nucleatum subsp. nucleatum, and F. nucleatum subsp. vincentii) 627 open reading frames unique to F. nucleatum subsp. polymorphum ATCC 10953 were identified. A large percentage of these mapped within one of 28 regions or islands containing five or more genes. Seventeen percent of the clustered proteins that demonstrated similarity were most similar to proteins from the clostridia, with others being most similar to proteins from other gram-positive organisms such as Bacillus and Streptococcus. A ten kilobase region homologous to the Salmonella typhimurium propanediol utilization locus was identified, as was a prophage and integrated conjugal plasmid. The genome contains five composite ribozyme/transposons, similar to the CdISt IStrons described in Clostridium difficile. IStrons are not present in the other fusobacterial genomes. These findings indicate that F. nucleatum subsp. polymorphum is proficient at horizontal gene transfer and that exchange with the Firmicutes, particularly the Clostridia, is common

    Amplified and selective assay of collagens by enzymatic and fluorescent reactions

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    Sensitive and selective assay of collagen is of substantial importance to the diagnostic study of health- and aging-related failures. In this paper, we describe a highly specific and sensitive method for the assay of whole collagens in biological samples using a novel fluorogenic reagent, 3,4- dihydroxyphenylacetic acid (3,4-DHPAA). The 3,4-DHPAA reagent can selectively detectN-terminal Gly-containing peptides (NGPs) in the presence of sodium borate and NaIO4. Under conditions optimized, this assay format for collagen, termed 3,4-DHPAA assay method showed a good linear relationship between the amplified FL signals and the collagen concentrations from 0.18 to 12 μg/ml. Therefore the sensitive determination of intracellular collagens in cheek tissue and HeLa cells was individually possible without any separation protocol. The dual recognitions of the collagens in the samples could be performed by the enzymatic digestion and the FL reaction. The proposed assay method enables the determination facile, specific, sensitive and quantitative for biogenic collagens
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