Christopher Medway edited Results and Discussion.tex  over 8 years ago

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The presence of the pYV plasmid is regarded as one of the key elemnts separating pathogenic (high and low) from non-pathogenic yersinia; the former includes \textit{y.enterocolitica} 1B and 2-5, whereas the latter includes \textit{y.enterocolitica} 1A. pYV is understood the be required to inflammation of the intestines following infection, and carries the T3SS-Yop secretion system that is instrumental in biovar virulance \cite{11418330}. A nucleotide blast of all assembled contigs against i) NCBI plasmid library (taxid:36549) and ii) pYV reference sequence (GenBank:NZ_CP009845.1), failed to find any evidence for pYV in this sample. As an alternative approach cBAR (http://csbl.bmb.uga.edu/~ffzhou/cBar/) was used isolate contigs likely to be extrachromosomal \cite{20538725}. This approach also failed to support the presence of pYV in this sample.  Another genomic feature of Yersinia that deliniates pathogenic and non-pathogenic biovars in the 'high-pathogenicity island' (HPI)  \cite{11418330}. The HPI is present in highly pathogenic yersinia (pestis, pseudotuberculosis III amd enterocolitica 1B) and absent in mildly- and non-pathogenic biovars \cite{11418330}. Although the arcitecture of the HPI differs between yersinia species, there is a common repertoise of yersiniabactin genes. The HPI found in \textit{Y.enterocolitica}, HPI_Yen, is approximatly 44kbp, larger than the HPI_Yps (36.8kbp) found in other pathogenic Yersinia \cite{15493818}. Yersiniabactin is a sidophore pivitol for the harnessing and trafficking iron, an essential cofactor in many enzymatic reactions. HPI_Yen comprises of \textit{irp1-9}, textit{YbtA} and \textit{fyuA}, in adittion to insertion sequennces; IS1328 and IS1400. A single 157kb contig captures the HPI in our query biovar. Genes known to flank the HPI, glycosyl hydrollacZ locus on one flank,