Project description:Salmonella enterica serovar Typhimurium (S. Typhimurium) definitive phage type 104 (DT104) has caused significant morbidity and mortality in humans and animals for almost three decades. We have completed the full DNA sequence of one DT104 strain, NCTC13348 and show that the main differences between the genome of this isolate and the previously sequenced S. Typhimurium LT2 lie in integrated prophage elements and the Salmonella Genomic Island 1 encoding antibiotic resistance genes. Thirteen isolates of S. Typhimurium DT104 with different pulsed field gel electrophoresis (PFGE) profiles were analyzed by multi locus sequence typing (MLST), plasmid profiling, hybridization to a Pan-Salmonella DNA microarray and prophage-based multiplex PCR. All the isolates belonged to a single MLST type ST19. Microarray data demonstrated that the 13 DT104 isolates were remarkably conserved in gene content. The PFGE band-size differences in these isolates could be explained to a great extent by changes in prophage and plasmid content. Thus, here the nature of variation in different S. Typhimurium DT104 isolates is further defined at the genome level illustrating how this phage type is evolving over time.
Project description:A collection of 61 Salmonella enterica serovar Typhimurium (S. Typhimurium) of animal and human origin, matched as closely as possible by phage type, antimicrobial resistance pattern and place / time of isolation, and sourced from farms or hospitals in Scotland, were analysed by antimicrobial susceptibility testing, phage typing, pulsed field gel electrophoresis (PFGE), plasmid profiling and DNA microarrays. PFGE of all 61 isolates revealed ten PFGE profiles, which clustered by phage type and antibiotic resistance pattern, with human and animal isolates distributed between PFGE profiles. Analysis of 23 representative S. Typhimurium strains hybridised to a composite Salmonella DNA microarray identified a small number of specific regions of genome variation between different phage types and PFGE profiles. These variable regions of DNA were typically located within prophage-like elements. Simple PCR assays were subsequently designed to discriminate between different isolates from the same geographical region.
Project description:Transcriptional profiles of a chlorhexidine tolerant Salmonella Typhimurium were compared to its, chlorhexidine sensitive, isogenic progenitor isolate. RNA was extracted from mid-log phase cells from both isolates, without chlorhexidine exposure and following exposure to 1 µg/ ml of chlorhexidine for 30 minutes. Transcriptional profiles of the tolerant isolate were compared to the sensitive isolate, with and without chlorhexidine exposure.
Project description:Salmonella enterica subsp. enterica contains more than 2,600 serovars of which four are of major medical relevance for humans. While the typhoidal serovars (Typhi and Paratyphi A) are human-restricted and cause enteric fever, non-typhoidal Salmonella serovars (Typhimurium and Enteritidis) have a broad host range and predominantly cause gastroenteritis. In this study, we compared the core proteomes of Salmonella Typhi, Paratyphi A, Typhimurium and Enteritidis using contemporary proteomics. Five isolates, covering different geographical origins, and one reference strain per serovar were grown in vitro to the exponential phase. Protein levels of orthologous proteins between serovars were compared and subjected to gene ontology term enrichment and inferred regulatory interactions. Differential expression of the core proteomes of the typhoidal serovars appears mainly related to cell surface components and, for the non-typhoidal serovars, to pathogenicity. Our findings may guide future development of novel diagnostics and vaccines, and understanding of disease progression.
Project description:To have a global picture of the miRNAs regulated upon Salmonella infection, we assessed small RNA changes, by RNA-sequencing, of HeLa cells infected with Salmonella Typhimurium compared with mock-treated cells . In addtion to the total population, we evaluated miRNA expression in the fraction of HeLa cells with internalized bacteria (Salmonella-positive), as well as in bystander cells, separated by fluorescence activated cell sorting (FACS)
Project description:We describe how searching chimeric spectra with post-processing including MS²PIP-derived features aids the identification of hypothetical and unannotated proteins. We apply our workflow to the well-characterized human bacterial pathogen Salmonella enterica serovar Typhimurium (S. Typhimurium) and validate novel protein-coding regions with by ribo-seq translation evidence. We further elaborate how riboproteogenomics is instrumental for reannotating ORFs and the discovery of novel ORFs across bacteria.
Project description:Transcriptional profiles of a chlorhexidine tolerant Salmonella Typhimurium were compared to its, chlorhexidine sensitive, isogenic progenitor isolate. RNA was extracted from mid-log phase cells from both isolates, without chlorhexidine exposure and following exposure to 1 µg/ ml of chlorhexidine for 30 minutes. Transcriptional profiles of the tolerant isolate were compared to the sensitive isolate, with and without chlorhexidine exposure. Carried out using 3 biological replicates for each sample; each sample hybridised in a two-channel hybridization against Salmonella genomic DNA as the comparator/reference