%0 Journal Article
%T Characterization of the expression of Salmonella Type III secretion system factor PrgI, SipA, SipB, SopE2, SpaO, and SptP in cultures and in mice
%A Hao Gong
%A Jing Su
%A Yong Bai
%A Lu Miao
%A Kihoon Kim
%A Yonghua Yang
%A Fenyong Liu
%A Sangwei Lu
%J BMC Microbiology
%D 2009
%I BioMed Central
%R 10.1186/1471-2180-9-73
%X In this study, we have constructed bacterial strains that contain a FLAG epitope inserted in frame to SPI-1 genes prgI, sipA, sipB, sopE2, spaO, and sptP, and investigated the expression of the tagged proteins both in vitro and in vivo during murine salmonellosis. The tagged Salmonella strains were inoculated intraperitoneally or intragastrically into mice and recovered from various organs. Our results provide direct evidence that PrgI and SipB are expressed in Salmonella colonizing the spleen and cecum of the infected animals at early and late stages of infection. Furthermore, this study demonstrates that the SpaO protein is expressed preferably in Salmonella colonizing the cecum but not the spleen and that SptP is expressed preferably in Salmonella colonizing the spleen but not the cecum.These results suggest that Salmonella may express different SPI-1 proteins when they colonize specific tissues and that differential expression of these proteins may be important for tissue-specific aspects of bacterial pathogenesis such as gastroenterititis in the cecum and systemic infection in the spleen.Salmonella enterica is among the most important and common etiological factors of food-borne disease [1-3]. Its infection causes a diverse range of diseases from mild self-limiting gastroenterititis to fatal systemic typhoid fever. S. enterica serovar Typhimurium, which can lead to various diseases in different hosts [4], is an important source of bacterial poisoning of contaminated food and water. Infection of humans with S. typhimurium usually causes self-limiting enterocolitis, but there are serious consequences when systemic invasion occurs. Systemic infection in sensitive mice somewhat simulates the pathological process of typhoid fever in human patients and it is thus an appropriate model to assess gene expression associated with invasiveness as well as colonization [4]. Understanding the process of bacterial infection and pathogenesis is central in developing novel strat
%U http://www.biomedcentral.com/1471-2180/9/73