Function of sahH gene in exopolysaccharides synthesis of Streptococcus mutans LuxS null strain / 上海交通大学学报（医学版）

Objective: To investigate the function of sahH gene in exopolysaccharides synthesis of Streptococcus mutans LuxS null strain. Methods: sahH+luxS-SmUA159 was constructed by introducing sahH gene into Streptococcus mutans LuxS null strain, while PIB169+luxS-SmUA159 and its wild strain SmUA159 were used as vector control and blank control. Real-time qPCR and anthrone test were performed to investigate the differences in exopolysaccharides synthesis among sahH+luxS-SmUA159, PIB169+luxS-SmUA159 and the wide-type strain SmUA159. Results: The transcriptional levels of gtfA and gtfD were upregulated in the sahH+luxS-SmUA159, compared to SmUA159 and PIB169+luxS-SmUA159 (both P<0.05), but there was no statistical difference in the transcriptional levels of gtfB and gtfC. The results of the anthrone test showed exopolysaccharides synthesis of the three groups was also similar. Conclusion: sahH gene affects the expression of some genes related to exopolysaccharides synthesis, but it has little effect on the whole content of bacterial exopolysaccharides.

Function of sahH gene in exopolysaccharides synthesis of Streptococcus mutans LuxS null strain / 上海交通大学学报（医学版）

Objective·To investigate the function of sahH gene in exopolysaccharides synthesis of Streptococcus mutans LuxS null strain. Methods·sahH+luxS-SmUA159 was constructed by introducing sahH gene into Streptococcus mutans LuxS null strain,while PIB169+luxS-SmUA159 and its wild strain SmUA159 were used as vector control and blank control. Real-time qPCR and anthrone test were performed to investigate the differences in exopolysaccharides synthesis among sahH+luxS-SmUA159, PIB169+luxS-SmUA159 and the wide-type strain SmUA159. Results·The transcriptional levels of gtfA and gtfD were upregulated in the sahH+luxS-SmUA159,compared to SmUA159 and PIB169+luxS-SmUA159(both P<0.05),but there was no statistical difference in the transcriptional levels of gtfB and gtfC.The results of the anthrone test showed exopolysaccharides synthesis of the three groups was also similar. Conclusion·sahH gene affects the expression of some genes related to exopolysaccharides synthesis,but it has little effect on the whole content of bacterial exopolysaccharides.

Influence of 3,3'-diindolylmethane on expression of inflammatory cytokines in periodontal ligament cells induced by lipopolysaccharide / 上海交通大学学报（医学版）

Objective·To investigate the effect of 3,3'-diindolylmethane (DIM) on the expression of inflammatory cytokines in human periodontal ligament cells (hPDLCs) induced by lipopolysaccharide (LPS) and to study the related mechanism.Methyls· hPDLCs were isolated and cultured,and CCK-8 method was used to detect the effect of DIM on the proliferation of hPDLCs.hPDLCs were randomly divided into 4 groups:blank group (without LPS and DIM),LPS group (10 μg/mL LPS),10 μg/mL LPS+6.25 μg/mL DIM,10 μg/mL LPS+12.50 μg/mL DIM.The cells of all groups were cultured for 12 h.The protein levels of TNF-α,IL-1β and IL-6 in supernatant were detected by enzyme linked immunosorbent assay.The change of mitogenactivated protein kinase (MAPK) and nuclear factor κB (NF-κB) signaling pathways were detected by Western blotting.Results· The cell viability was not affected when the DIM concentration was less than 50 μmol/L (P＞0.05).DIM at 6.25 and 12.50 μg/mL reduced the LPS-induced expression of TNF-α,IL-1β and IL-6 at protein levels (P＜0.05).DIM inhibited the activation of the NF-κB signaling pathway.Conclusion· DIM can reduce the LPS-induced inflammatory cytokine expression in hPDLCs via restraining the activation of the NF-κB signaling pathway.