Abstract:[Background] Salmonella is a kind of Gram-negative intestinal pathogen that relies primarily on type III secretion systems (T3SSs) to produce pathogenicity-associated effector proteins. The Salmonella pathogenicity island (SPI) is a key genetic region. The conditions of high-salt can induce the expression of effector proteins on SPI-1. [Objective] In order to explore the differential expression of glycoprotein of Salmonella enterica serovar Typhimurium under high-salt concentration, and to find meaningful effector glycoprotein. [Methods] Salmonella enterica serovar Typhimurium was cultured in common medium and high-salt medium, and then the cells were collected. The glycoproteins were enriched by hydrazine coupling method after ultrasonication and protein extraction. After the enzymatic hydrolysis, the glycoproteins were quantified by dimethyl-labeled quantitative method, and the labeled proteins were qualitatively and quantitatively analyzed by liquid chromatography-mass spectrometry. [Results] Mass spectrometry results showed that the expression of 19 glycoproteins in Salmonella significantly changed in the high salt environment. Among these, 10 glycoproteins were up-regulated, the most notably one was the outer membrane porin encoded by ompC. Nine glycoproteins were down-regulated, the most notably one was translation initiation inhibitor encoded by yjgF. [Conclusion] The expression levels of many important glycoproteins in Salmonella have significant changes at high-salt environments. This study has important significance in investigating the expression of effector glycoprotein produced by Salmonella SPI-1 and searching the pathogenic mechanism of Salmonella.
