中文摘要：

目的探讨扁桃酸代谢对新生隐球菌毒力作用的影响。方法采用套叠PCR方法,构建扁桃酸消旋酶、扁桃酸脱氢酶及过氧化氢铜胺氧化酶基因重组片段,利用基因枪将重组片段转入新生隐球菌JEC21,应用PCR筛选、DNA测序等方法对阳性克隆子进行筛选与鉴定。体外观察并检测突变菌株对多种应激条件的应答反应。结果成功构建了新生隐球菌JEC21扁桃酸消旋酶、扁桃酸脱氢酶及过氧化氢铜胺氧化酶的基因缺陷菌株（mreΔ,lmdΔ,pcaoΔ）,发现缺陷菌株mreΔ对于毒力功能影响不大,pcaoΔ、lmdΔ在高温、高渗、氧化应激等方面毒力减退,而黑色素分泌增加。结论扁桃酸代谢参与介导新生隐球菌毒力作用的调控,但其具体机制有待于进一步的研究探讨。

英文摘要：

Objective To explore the effect mandelic acid and its metabolism made on virulence of C.neoformans.Methods Constructed recombinant fragments of mandelate racemase,mandelate dehydrogenase and hydrogen peroxide copper amine oxidase by nested PCR,and put them into JEC21 through gene gun.Identified the positive clones by PCR,DNA sequencing.What＇s more,detected mutant strains in vitro responses to various stress conditions.Results Successfully constructed mutant strains（mreΔ,lmdΔ,pcaoΔ）,and found mreΔtook little effect on virulent factors,pcaoΔand lmdΔshowed weaker in high temperature,high permeability,oxidative stress but secreted more melanin.Conclusion Mandelic acid and its metabolism play role in mediating the virulence of C.neoformans,but the exact mechanism needs further study.