Project description:Comparative genomic hybridization of a temporally and locally diverse set of S. enterica ssp I serovar Enteritidis isolates, and some closely related serovar Dublin and Gallinarum strains, to the sequenced Enteritidis PT4 Keywords: other
Project description:Investigation of whole genome gene expression level changes in Salmonella enterica serova Enteritidis and Typhimurium under chlorine treatment
Project description:Excisable Genomic Islands (EGIs) are horizontally acquired genetic elements that harbor an array of genes with diverse functions. ROD21 is an EGI found integrated in the chromosome of Salmonella enterica serovar Enteritidis (Salmonella ser. Enteritidis). While this island is known to be involved in the capacity of Salmonella ser. Enteritidis to cross the epithelial barrier and colonize sterile organs, the role for most of ROD21 genes remains unknown, and thus identification of their function is fundamental to understand the impact of this EGI on the bacterium pathogenicity. Therefore, in this work we used a bioinformatical approach to evaluate the function of ROD21-encoded genes and delve into the characterization of SEN1990, a gene encoding a putative DNA-binding protein. We characterized the predicted structure of SEN1990, finding that this protein contains a three-stranded winged helix-turn-helix (wHTH) DNA-binding domain. Additionally, we identified homologs of SEN1990 among other members of the EARL EGIs. Furthermore, we deleted SEN1990 in Salmonella ser. Enteritidis, finding no differences in the replication/maintenance of the excised ROD21, disconfirming the previous Refseq annotation of the protein. High-throughput RNA-sequencing was carried out to evaluate the effect of the SEN1990 absence on the bacterium global transcription. We found a downregulated expression of oafB, an SPI-17-encoded acetyltransferase involved in O-antigen modification, which was restored when the deletion of SEN1990 was complemented. Our findings suggests that SEN1990 encodes a wHTH domain-containing transcriptional activator that modulates the transcription of oafB from the SPI-17, suggesting a crosstalk between these pathogenicity islands and a possible new role of ROD21 in the pathogenesis of Salmonella ser. Enteritidis.
Project description:Transcriptional profiles of mid-exponentially growing Salmonella enterica sv Enteritidis PT8 cultures in response to exposure to trans-cinnamaldehyde (0.01%; 0.75mM) or eugenol (0.04%; 2.46mM)
Project description:Comparative genomic hybridization of a temporally and locally diverse set of S. enterica ssp I serovar Enteritidis isolates, and some closely related serovar Dublin and Gallinarum strains, to the sequenced Enteritidis PT4
Project description:Even though the incidence of salmonellosis in humans has decreased over the last years, Salmonella spp. are still a leading cause of foodborne outbreaks in Europe (Anon., 2014). Of more than 2500 different serovars of Salmonella enterica, S. enterica serovar Enteritidis (S. Enteritidis) is the most frequently reported serovar in relation to food borne disease, and egg and egg products are the most important vehicles (Anon., 2014). It has recently been shown that S. Enteritidis is superior to other serovars tested regarding survival in egg white, which may explain why many egg borne outbreaks are caused by this serovar (De Vylder et al., 2013). The genetic background for this apparent better adaptation to survival in egg is only partially known. The aim of this work was to carry out gene expression analysis in order to understand how S. Enteritidis adapts to growth in the hostile environment of egg. This study analyzed gene expression of this bacterium during growth in whole egg, and whether highly expressed genes were essential for the growth. High quality RNA was extracted from S. Enteritidis using an improved modified RNA-extraction protocol. Global gene expression during growth in whole egg was compared to growth in LB-medium using DNA array method. Twenty-six genes were significantly upregulated during growth in egg; these belonged to amino acids biosynthesis, di/oligopeptide transport system, biotin synthesis, ferrous iron transport system, and type III secretion system. Significant downregulation of 15 genes related to formate hydrogenlyase (FHL) and trehalose metabolism was observed. The results suggested that S. Enteritidis is starved for amino-acids, biotin and iron when growing in egg.