Project description:The Salmonella effector SteC is the only protein kinase encoded by Salmonella pathogenicity island 2 that is secreted through the type III secretion system. SteC is known to trigger actin rearrangement via the phosphorylated MEK pathway, and our previous experiments demonstrated that the migration process of macrophages found during Salmonella infection is dependent on the rearrangement of the host cell actin backbone and the action of SteC.To further investigate the target of SteC in the host, we constructed a SteC-RAW264.7 cell line and performed phosphomics analysis using 4D-FastDIA to identify the direct substrates of SteC that trigger macrophage migration and lead to cytoskeletal rearrangement.
Project description:We conducted comparative gene co-expression network (GCN) analyses of two O113:H21 STEC strains: EH41, reference strain, isolated from hemolytic-uremic syndrome patient in Australia, and Ec472/01, isolated from cattle feces in Brazil. These strains were cultured in fresh or in Caco-2 cell conditioned media. GCN analyses were also accomplished for cultured Caco-2 cells exposed to EH41 or Ec472/01. Differential transcriptome profiles for EH41 and Ec472/01 were not significantly changed by exposure to fresh or Caco-2 conditioned media. Conversely, global gene expression comparison of both strains cultured in conditioned medium revealed a gene set exclusively expressed in EH41, which includes the dicA putative virulence factor regulator. Network analysis showed that this set of genes constitutes an EH41 specific transcriptional module. The GCNs of Caco-2 cells exposed to EH41 or to Ec472/01 presented a major transcriptional module containing many hubs related to inflammatory response that was not found in the GCN of control cells. Moreover, EH41 seems to cause gene network dysregulation in Caco-2. Therefore, EH41 virulence may be derived from its capacity for dysregulating enterocyte genome functioning and its enhanced enteric survival due to slow growth.
Project description:A food-borne outbreak of haemorrhagic colitis (HC) and HUS caused by E. coli O103:H25 occurred in Norway, 2006. The outbreak included 17 registered cases, of which 10 developed HUS. The aim of this study was to characterize two E. coli O103:H25 isolates from this outbreak. Only one of the isolates carry the stx2 gene (by PCR). Since they have the same typing profile by typing method MLVA, we expect the isolates to have identical gene content except from an Stx2-encoding phage. Therefore, we further investigate whether the Stx2-encoding phage has any impact on the gene expression. Keywords: mixed, gene expression, comparative genomic hybridization
