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Streptococcus pyogenes is a human pathogen that causes various diseases. Numerous virulence factors secreted by S. pyogenes are involved in pathogenesis. The peroxide regulator (PerR) is associated with the peroxide resistance response and pathogenesis, but little is known about the regulation of the secretome involved in virulence. To investigate how PerR regulates the expression of the S. pyogenes secretome involved in virulence, a perR deficient mutant was used for comparative secretomic analysis with a wild-type strain. The conditioned medium containing secreted proteins of a wild-type strain and a perR deficient mutant at the stationary phase were collected for two-dimensional gel electrophoresis analysis, where protease inhibitors were applied to avoid the degradation of extracellular proteins. Differentially expressed protein spots were identified by liquid chromatography electrospray ionization tandem MS. More than 330 protein spots were detected on each gel. We identified 25 unique up-regulated proteins and 13 unique downregulated proteins that were directly or indirectly controlled by the PerR regulator. Among these identified proteins, mitogen factor 3 (MF3), was selected to verify virulence and the expression of gene products. The data showed that MF3 protein levels in conditioned medium, as measured by immunoblot analysis, correlated well with protein levels determined by two-dimensional gel electrophoresis analysis. We also demonstrated that PerR bound to the promoter region of the mf3 gene. The result of an infection model showed that virulence was attenuated in the mf3 deficient mutant. Additional growth data of the wild-type strain and the mf3 deficient mutant suggested that MF3 played a role in digestion of exogenous DNA for promoting growth. To summarize, we conclude that PerR can positively regulate the expression of the secreted protein MF3 that contributes to the virulence in S. pyogenes. The analysis of the PerR-regulated secretome provided key information for the elucidation of the host-pathogen interactions and might assist in the

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A new homogeneous heteropolysaccharide (CMSPA90-1) was purified from bergamot by DEAE sepharose fast flow and Sephadex G-75 columns, and was shown to have a molecular weight of 17.6 kDa. Its chemical structure was elucidated by acid hydrolysis and methylation analysis, along with high-performance anionexchange chromatography, Fourier transform infrared spectroscopy coupled with gas chromatographymass spectrometry, NMR spectroscopies, the Congo red test, and circular dichroism. CMSPA90-1 consisted of a pyranoside and funanside with branches containing aand b-configurations simultaneously. Arabinose and glucose might form an arabinoglucan backbone. The ultrastructure of CMSPA90-1 was further characterized by scanning electron microscopy (SEM) and atomic force microscopy (AFM). The results of thermogravimetric analysis (TGA) revealed that CMSPA90-1 had good thermal stability. The results of DPPHc and ABTS + c radical scavenging assays indicated that CMSPA90-1 exhibited free-radical-scavenging properties. Otherwise, CMSPA90-1 could promote the proliferation of mouse splenocytes and the neutral red phagocytosis of RAW264.7 cells, which indicated that CMSPA90-1 could be researched and developed as one of the potential functional foods or natural medicines.