ABSTRACT: Comparison of High Resolution Viruelnce Allelic Profiling (HReVAP) typing with Multilocus Sequence Typing and Whole Genome SNPs analysis for typing VTEC strains
Project description:This project has two goals. Firstly, to compare the gene expression profiles of Caco cells following exposure to Verocytotoxigenic E. coli0157:H7 (VTEC) isolates from food animals (bovine, ovine, porcine) and human in an effort to assess the invasive and toxigenic potential of isolates of different origin. All sources contain the common virulence and type 3 secretory system genes. Secondly, to compare the gene expression profiles of Caco-2 cells following exposure to VTEC isolates that contain (positive) or do not contain (negative) the genes of the type 3 secretory system (TTSS).
Project description:Verotoxigenic Escherichia coli (VTEC) are a leading cause of food-borne illness. Fruit and vegetables are recognised as an important source of the pathogen and can account for ~ 25 % of food-borne VTEC outbreaks, globally. The ability of VTEC to colonise leaves and roots of leafy vegetables, spinach (Spinacia oleracea) and lettuce (Lactuca sativa), was compared. The highest levels of colonisation occurred in the roots and rhizosphere, whereas colonisation of the leaves was lower and significantly different between the species. Colonisation of the leaves of prickly lettuce (L. serriola), a wild relative of domesticated lettuce, was especially poor. Differential VTEC gene expression in spinach extracts was markedly different for three tissue types, with little overlap. Comparison of expression in the same tissue type, cell wall polysaccharides, for lettuce and spinach also showed substantial differences, again with virtually no overlap. The transcriptional response was largely dependent on temperatures that are relevant to plant growth, not warm-blooded animals. The data show that VTEC adaptation to plant hosts and subsequent colonisation potential is underpinned by wholescale changes in gene expression that are specific to both plant tissue type and to the species.
Project description:Verotoxigenic Escherichia coli (VTEC) are a leading cause of food-borne illness. Fruit and vegetables are recognised as an important source of the pathogen and can account for ~ 25 % of food-borne VTEC outbreaks, globally. The ability of VTEC to colonise leaves and roots of leafy vegetables, spinach (Spinacia oleracea) and lettuce (Lactuca sativa), was compared. The highest levels of colonisation occurred in the roots and rhizosphere, whereas colonisation of the leaves was lower and significantly different between the species. Colonisation of the leaves of prickly lettuce (L. serriola), a wild relative of domesticated lettuce, was especially poor. Differential VTEC gene expression in spinach extracts was markedly different for three tissue types, with little overlap. Comparison of expression in the same tissue type, cell wall polysaccharides, for lettuce and spinach also showed substantial differences, again with virtually no overlap. The transcriptional response was largely dependent on temperatures that are relevant to plant growth, not warm-blooded animals. The data show that VTEC adaptation to plant hosts and subsequent colonisation potential is underpinned by wholescale changes in gene expression that are specific to both plant tissue type and to the species.
Project description:Background. The bacterial foodborne pathogen Campylobacter jejuni is a common cause of acute gastroenteritis and is also associated with the postinfectious neuropathies, Guillain-Barré and Miller Fisher syndromes. This study described the use of multilocus sequence typing and DNA microarrays to examine the genetic content of a collection of South African C. jejuni strains, recovered from patients with enteritis, Guillain-Barré or Miller Fisher syndromes. Methodology/Principal Findings. The comparative genomic analysis by using multilocus sequence typing and DNA microarrays demonstrated that the South African strains with Penner heat-stable (HS) serotype HS:41 were clearly distinct from the other South African strains. Further analysis of the DNA microarray data demonstrated that the serotype HS:41 strains from South African GBS and enteritis patients are highly similar in gene content. Interestingly, the South African HS:41 strains were distinct in gene content when compared to serotype HS:41 strains from other geographical locations due to the presence of genomic islands, referred to as Campylobacter jejuni integrated elements. Only the genomic integrated element CJIE1, a Campylobacter Mu-like prophage, was present in the South African HS:41 strains whereas absent in the closely-related HS:41 strains from Mexico. A more distantly-related HS:41 strain from Canada possessed both genomic integrated elements CJIE1 and CJIE2. Conclusion/Significance. These findings demonstrated that these C. jejuni integrated elements may contribute to the differentiation of closely-related C. jejuni strains. In addition, the presence of bacteriophage-related genes in CJIE1 may probably contribute to increasing the genomic diversity of these C. jejuni strains. This comparative genomic analysis of the foodborne pathogen C. jejuni provides fundamental information that potentially could lead to improved methods for analyzing the epidemiology of disease outbreaks and their sources. Keywords: comparative genomic indexing analysis
Project description:Highly specific amplification of complex DNA pools without bias or template-independent products (TIPs) remains a challenge. We have developed a procedure using phi29 DNA polymerase and trehalose and optimized control of amplification to create micrograms of specific amplicons without TIPs from down to sub-femtograms of DNA. The amplicons from 5 ng and 0.5 ng DNA, which were from originally good quality of gDNA (05-050), or partially degraded gDNA (04-018), were validate with Illumina HumanHap550-Duo Genotyping Beadchip. As seen in (Suppl. Table 5a), the call rates (97.30% to 99.07%) and accuracy or concordance ( > 99.85% for the SNPs called in both amplicon and natural reference) for 5 ng derived amplicons with both Wpa and Gv2 were close to each other and close to native gDNA (call rate: 98.3% to 99.75%). These call rates were better than a recent report (amplicon 95.9% vs. un-amplified 98.5%), in which the early kit Repli-g 625S was applied, and re-genotyping was performed when the performance was low and duplicate samples were filtered for the highest call rate. The genotyping accuracy of Wpa was actually in the same range as the variation in technical replicates with similar SNP typing arrays (99.87% and 99.88%, replicated Affymetrix array, or between Affymetrix and Illumina arrays). Importantly, the genotyping concordance for amplicons generated from 0.5 ng with Wpa (99.88% and 99.69%) were also close to the technical replicates. In this case, the call rates of Wpa were slightlyreduced compared to that with 5 ng input, but the call rate for the partially degraded sample 04-018, was modestly improved over Gv2 (92.06 % vs. 90.53%). Wpa data also showed some amplification non-uniformity among different locations, resulting in some âartificial CNVsâ similar to Gv2 (exampled as in Suppl. Fig. 5 and Suppl. Table 6), with the outputs obtained by taking unamplified gDNAs as their reference. This imbalance however was consistent and reproducible for each method but different between Wpa and Gv2. These artificial CNVs can be efficiently cancelled if pair-wise amplified test and reference are compared, as observed in CGH result (Fig. 4 and Suppl. Fig. 4), also supported by others {Pugh 2008}. It is interesting to note that the representation of chromosomal terminal sequences was greatly improved with Wpa compared with Gv2 (Fig. 5), and that some of these regions were significantly under-amplified or even lost with Gv2 (Suppl. Fig. 5 and Suppl. Table 6, 7), as also independently reported recently {Pugh 2008}. This occurred especially in the terminal 3 to 5 Mb and sometimes extended to 10 Mb in many chromosome termini, and was particularly serious when low levels or degraded DNA was as input. An analysis for 5 Mb termini is shown (Suppl. Table 5b calculated all involved SNPs as a cohort. Fig. 5 and Suppl. Tables 6 and 7 were the result for each chromosome terminus). Importantly, the SNP typing was also greatly improved, outstandingly exemplified by the amplicons of 0.5 ng input for the partially degraded 04-018, with Wpa versus Gv2 call rate of 91.9% vs. 84.45% and accuracy of 99.57% vs. 98.62%. The result also showed that these terminal regions underrepresentation in Gv2 was not absolutely associated with the distance-to-end, but possibly was a sequence related issue. Keywords: Whole-pool amplification, whole genome SNP typing The overall goal of the part of study was a validation of the quality of the amplicons from different amounts (5ng and 0.5 ng) of original starting gDNA, good quality (sample 05-050) or partially degraded gDNA (sample 04-018), with our new procedure Wpa, and with native gDNA as control, in terms of the call rate and accuracy (allele bias) in addition to the uniformity of the sequence amplified (sequence representation or sequence bias). Amplified or native genomic DNA isolated from patients was in-parallel analyzed/genotyped with the same experimental platform, of which the native genomic DNAs were used as the standard controls. For the sequence representation, the two alleles of the SNPsâ signal of a panel of multiple native DNAsâ signal provided by the experimental platform (Illumina) was used as the reference, so that an abstract signal for sequence representation of each SNP and for all SNPs was obtained.
Project description:Purpose: This study uses a high-throughput glycan microarray to develop a novel method to assign ABO blood type. The method will then be applied to samples from patients treated with PROSTVAC to determine if blood type correlates with survival Results: Many blood group A and B antigens correlate with blood type. Blood typing is best achieved using a combination of 10 signals Conclusion: ABO blood type can be determined with greater than 97% accuracy using only 4 microliters of serum.