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目的:探讨草决明对MRSA菌株的色素产生及毒力表达影响,寻找抑制毒力表达的基因靶标,探讨草决明的药理作用及MRSA菌株的毒力变化机制。方法:草决明采用水提和醇提法,用血浆凝固酶实验、光密度测定技术、抗过氧化氢实验观察草决明对不同组MRSA菌株的作用,通过荧光定量PCR技术观察各毒力表达基因及调控基因变化。结果:12.5、3.125μg/mL的草决明水提液和醇提液不影响MRSA菌的生长,草决明提取液降低了MR-SA菌色素合成及血浆凝固酶表达,MRSA菌抗氧化能力降低;MRSA菌分别受水提液及醇提液处理后,溶血素活性出现分离现象;荧光定量PCR结果表明抑制毒力表达的基因靶标为agr,但溶血素基因不受其调控。结论:草决明通过基因靶标agr降低了MRSA菌的部分毒素表达,具有一定的临床应用价值。
OBJECTIVE: To investigate the effect of Trichostatin on pigment production and virulence expression of MRSA strains, to search for gene targets that inhibit the expression of virulence, and to explore the pharmacological effects of Cassia medusa and the virulence mechanism of MRSA strains. METHODS: The aqueous extracts and alcohol extracts of Cassia were used to observe the effects of Cassia to different groups of MRSA strains by plasma coagulation enzyme assay, densitometry and anti-hydrogen peroxide assay. Each virulence was observed by fluorescence quantitative PCR. Express genes and regulate gene changes. RESULTS: The aqueous extracts and alcohol extracts of Cassia roxburghii of 12.5 and 3.125 μg/mL did not affect the growth of MRSA bacteria. Cassia ocellatus extract reduced the synthesis of MR-SA pigment and the expression of plasma coagulase, and the antioxidant capacity of MRSA bacteria. Reduced; MRSA strains were treated with water extracts and alcohol extracts, the separation of hemolysin activity appeared; fluorescence quantitative PCR results showed that the gene target for inhibition of virulence expression was agr, but the hemolysin gene was not regulated. Conclusion: Cassia can reduce the expression of some toxins in MRSA through the gene target agr, which has certain clinical application value.