Project description:Three translatomic approaches were applied to the foodborne pathogen Campylobacter jejuni to identify translated open reading frames, start codons, and stop codons and reveal novel small proteins
Project description:Although the major food-borne pathogen Campylobacter jejuni has been isolated from diverse animal, human and environmental sources, our knowledge of genomic diversity in C. jejuni is based exclusively on human or human food-chain-associated isolates. Studies employing multilocus sequence typing have indicated that some clonal complexes are more commonly associated with particular sources. Using comparative genomic hybridization on a collection of 80 isolates representing diverse sources and clonal complexes, we identified a separate clade comprising a group of water/wildlife isolates of C. jejuni with multilocus sequence types uncharacteristic of human food-chain-associated isolates. By genome sequencing one representative of this diverse group (C. jejuni 1336), and a representative of the bank-vole niche specialist ST-3704 (C. jejuni 414), we identified deletions of genomic regions normally carried by human food-chain-associated C. jejuni. Several of the deleted regions included genes implicated in chicken colonization or in virulence. Novel genomic insertions contributing to the accessory genomes of strains 1336 and 414 were identified. Comparative analysis using PCR assays indicated that novel regions were common but not ubiquitous among the water/wildlife group of isolates, indicating further genomic diversity among this group, whereas all ST-3704 isolates carried the same novel accessory regions. While strain 1336 was able to colonize chicks, strain 414 was not, suggesting that regions specifically absent from the genome of strain 414 may play an important role in this common route of Campylobacter infection of humans. We suggest that the genomic divergence observed constitutes evidence of adaptation leading to niche specialization. Data is also available from <ahref=http://bugs.sgul.ac.uk/E-BUGS-95 target=_blank>BuG@Sbase</a>
Project description:Chromosomal structural variation can cause alterations in gene dosage and gene regulation between genomes. Structural variants producing a change in the number of copies of a genomic region are termed copy number variants (CNVs). CNVs have been demonstrated to have causative effects on both Mendelian and complex traits, including susceptibility to infectious diseases. We are interested in mapping CNVs to domesticated chicken breeds to help determine structural variation between genomes that influences economically important traits. For this study, Fayoumi, Leghorn, Line A broiler and Line B broiler chicken were chosen. Fayoumi and Leghorn chickens were selected as these two breeds harbor different responses certain pathogens like Avian Influenza Virus and coccidiosis; Broiler Line A and Line B indivduals were chosen as they harbor different intestinal colonization loads to the bacterium Campylobacter jejuni. Campylobacter genetic Line A and genetic Line B are from a commercial producer have been previously described as either resistant (Line A) or susceptible (Line B). Highly inbred chicken lines Fayoumi M15.2 (n=6) and Leghorn GHs6 (n=6) and broilers from Line A (n=24 individuals in pools of 4) and Line B (n=24 individuals in pools of 4)were subjected to array Comparative Genomic Hybridization (aCGH). Each sample was normalized to a Red Jungle Fowl reference. CNVs for each individual and between lines were determined. The major goal of this study was to discover and characterize CNVs in chickens to further narrow in on Quantitative Trait Loci (QTLs) affecting disease response.
Project description:Six bacterial genomes, Geobacter metallireducens GS-15, Chromohalobacter salexigens, Vibrio breoganii 1C-10, Bacillus cereus ATCC 10987, Campylobacter jejuni subsp. jejuni 81-176 and Campylobacter jejuni NCTC 11168, all of which had previously been sequenced using other platforms were re-sequenced using single-molecule, real-time (SMRT) sequencing specifically to analyze their methylomes. In every case a number of new N6-methyladenine (m6A) and N4-methylcytosine (m4C) methylation patterns were discovered and the DNA methyltransferases (MTases) responsible for those methylation patterns were assigned. In 15 cases it was possible to match MTase genes with MTase recognition sequences without further sub-cloning. Two Type I restriction systems required sub-cloning to differentiate their recognition sequences, while four MTases genes that were not expressed in the native organism were sub-cloned to test for viability and recognition sequences. No attempt was made to detect 5-methylcytosine (m5C) recognition motifs from the SMRT sequencing data because this modification produces weaker signals using current methods. However, all predicted m6A and m4C MTases were detected unambiguously. This study shows that the addition of SMRT sequencing to traditional sequencing approaches gives a wealth of useful functional information about a genome showing not only which MTase genes are active, but also revealing their recognition sequences. Examination of the methylomes of six different strains of bacteria using kinetic data from single-molecule, real-time (SMRT) sequencing on the PacBio RS.