Project description:Salmonella enterica variants exhibit diverse host adaptation, outcome of infection, and associated risk to humans. Analysis of 6,335 Salmonella isolates recovered from integrated human-animal surveillance in Emilia Romagna region, Northern Italy, (human population ca 4,500,000), from 2012 to 2017 showed that Salmonella enterica serovar Derby constitutes a swine associated serovar in this epidemiological context while representing also a significant causative agent of human infections. Comparison of the distribution of subtypes of Salmonella Derby from human and swine identified isolates with a distinct PFGE profile that were significantly less isolated in human infections than in swine infections compared to all other subtypes. Here we show that isolates with this PFGE profile form a distinct phylogenetic sub-clade within Salmonella Derby and exhibit a marked reduction in invasion and replication in human epithelial cells but a relatively small reduction in swine epithelial cells, in line with the epidemiological evidence. A single missense mutation in hilD, that encodes the master-regulator of the Salmonella Pathogenicity Island 1 (SPI-1), was identified in this lineage of Salmonella Derby. Since SPI-1 encodes for a primary system of Salmonella invasion into epithelial cells, we investigated the role of the observed mutation in detail. We demonstrated that the missense mutation results in a loss of function of HilD that accounts for the reduced invasion and replication in human epithelial cells while showing a relatively small impact on the interaction with swine cells. This finding is suggestive of a mechanism of invasion alternative to SPI-1 in the Salmonella-swine combination
Project description:FabR ChIP-chip on Salmonella enterica subsp. enterica serovar Typhimurium SL1344 using anti-Myc antibody against strain with chromosomally 9Myc-tagged FabR (IP samples) and wildtype strain (mock IP samples)
Project description:We performed affinity purification coupled to quantitative mass spectrometry (AP-qMS) for proteins belonging to retrons of Salmonella enterica. We quantified the proteome of rcaT point mutants in Salmonella enterica. We quantified the proteome of phage P1vir in E. coli.
Project description:Salmonella enterica causes serious global burden of morbidity and mortality and is a major cause of infant bacteremia in sub Saharan Africa. Diseases caused by Salmonella are treatable with antibiotics but successful antibiotic treatment has become difficult due to antimicrobial resistance. An effective vaccine together with public health effort may therefore be a better strategy to control these infections. Protective immunity against Salmonella depends primarily on T cell-mediated immune responses and therefore identifying relevant T cell antigens is necessary for Salmonella vaccine development. Our laboratory has used an immunoproteomics approach to identify Chlamydia T cell antigens that exhibited significant protection against Chlamydia infection in mice. In this study, we infected murine bone marrow derived dendritic cells from C57BL/6 mice with Salmonella enterica strain SL1344 followed by isolation of MHC class I and II- molecules and elution of bound peptides. The sequences of the peptides were then identified using tandem mass spectrometry. We identified 87 MHC class II and 23 MHC class I Salmonella derived peptides. Four of 12 peptides stimulated IFN-? production by CD4 T cells from the spleens of mice with persistent Salmonella infection. These antigens will be useful for Salmonella immunobiology research and are potential Salmonella vaccine candidates.
Project description:Investigation of whole genome gene expression level changes in a Salmonella enterica serovar Typhimurium 14028 delta GidA mutant The mutant described in this study is further analyzed in Shippy, D. C., N. M. Eakley, P. N. Bochsler, and A. A. Fadl. 2011. Biological and virulence characteristics of Salmonella enterica serovar Typhimurium following deletion of glucose-inhibited division (gidA) gene. Microb Pathog.
Project description:Investigation of whole genome gene expression level changes in a Salmonella enterica serovar Typhimurium UK1 delta-iacP mutant, compared to the wild-type strain. IacP is resoponsible for the secretion of virulence effector proteins via the type III secretion system, thereby contributing the virulence of S. Typhimurium. The mutants analyzed in this study are further described in Kim et al. 2011. Role of Salmonella Pathogenicity Island 1 Protein IacP in Salmonella enterica Serovar Typhimurium Pathogenesis. Infection and Immunity 79(4):1440-1450 (PMID 21263021).
Project description:Single-molecule read technologies allow for detection of epigenomic base modifications during routine sequencing by analysis of kinetic data during the reaction, including the duration between base incorporations at the elongation site (the "inter-pulse duration.") Methylome data associated with a closed de novo bacterial genome of Salmonella enterica subsp. enterica serovar Javiana str. CFSAN001992 was produced and submitted to the Gene Expression Omnibus.