Progress 09/30/00 to 12/31/04
Outputs
4d Progress report. This report documents research conducted under a Specific Cooperative Agreement between ARS and The Institute for Genomic Research (TIGR). Additional details of this research can be found in the report for the parent CRIS 1935-42000-052-00D Validation of the Effect of Interventions and Processes on Persistence of Pathogens on Foods. The objective of this subordinate project is to conduct whole-genome sequence comparisons of Listeria monocytogenes. Strain ATCC19116, a serotype 4c strain in genetic lineage 3, was sequenced to 8X coverage of the genome and the genes have been annotated. Previously, three L. monocytogenes strains, representing genetic lineage 1 (strains F2365 and H7858) and genetic lineage 2 (strain F6854), were either fully sequenced or sequenced to at least 8X coverage, and annotated. Genome comparisons have been updated to include the newly sequenced serotype 4c strain, and four other sequenced L. monocytogenes strains, all but
one of which were sequenced as part of this collaboration. There is high similarity among the strains. The majority of identified differences consist of phage insertions, transposable elements, and single nucleotide polymorphisms (SNPs). The SNPs present in the newly sequenced genome and in all other sequenced listeriae genomes have been identified in comparison to the fully sequenced L. monocytogenes serotype 4b strain, that being strain F2365. The SNP data are being analyzed to determine the genes that have been under selective pressures and which have lead to differences among the strains. The sequence data generated provides a wealth of basic information, accessible via the Internet at www.tigr.org, which is already being used by investigators worldwide to advance our understanding of the persistence and pathogenicity of this bacterium.
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Progress 10/01/03 to 09/30/04
Outputs
4. What were the most significant accomplishments this past year? D. Progress Report: This report serves to document research conducted under a Specific Cooperative Agreement between ARS and The Institute for Genomic Research (TIGR). Additional details of research can be found in the report for the parent CRIS 1935-42000-037-00D Develop Novel Genetic Based Intervention Strategies. The objective is to conduct whole-genome sequence comparisons of Listeria monocytogenes. The genomes of three strains have been fully sequenced and annotated and the sequencing of the whole genome of a 4th strain is nearly completed. To date, the results revealed subtle strain- and serotype-specific differences. The results also revealed that these genomes are syntenic, with the majority of the differences consisting of phage insertions, transposable elements, and single nucleotide polymorphisms. Comparison of the total genomic content of these strains has provided insight towards
defining the core genetic complement of listeriae. The sequence data generated provides a wealth of basic information, accessible via the Internet at www.tigr.org, that is already being used by investigators worldwide to advance our understanding of the persistence and pathogenicity of this bacterium.
Impacts
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