pvdQ基因在铜绿假单胞菌对白假丝酵母菌形态抑制作用中的功能

摘要

目的 拟研究长链高丝氨酸内酯降解基因pvdQ在铜绿假单胞菌对白假丝酵母菌形态抑制作用中的功能.方法 通过乙酸锂转化法构建CAI-4 HWP1-LacZ菌株,使用X-gal平板显色法检测3-oxo-C12-HSL对白假丝酵母菌形态转换的影响;观察与铜绿假单胞菌pvdQ高表达株、野生株PAO1共同培养时,白假丝酵母菌的形态变化,了解pvdQ基因在铜绿假单胞菌对白假丝酵母菌形态抑制作用中的功能.结果 400 μg 3-oxo-C12-HSL即可完全抑制白假丝酵母菌的形态转换.铜绿假单胞菌pvdQ高表达株和野生株PAO1均可抑制白假丝酵母菌菌丝形成.pvdQ高表达株对白假丝酵母菌的形态抑制作用较野生株PAO1减弱.结论铜绿假单胞菌通过分泌信号分子3-oxo-C12-HSL,可抑制白假丝酵母菌形态转换.随着pvdQ表达增加,铜绿假单胞菌对白假丝酵母菌的形态抑制作用减弱,即pvdQ基因在铜绿假单胞菌对白假丝酵母菌形态抑制作用中起负性调节作用.其作用机制可能与pvdQ基因对3-oxo-C12-HSL的水解作用有关.%Objective To study the function of long-chain homoserine lactones degradation gene pvdQ in inhibiting the morphologic change of Candida albicans by Pseudomonas aeruginosa. Methods After construction of CAI-4 HWPl-LacZ strain by lithium acetate transformation method,X-gal color plate was used to observe the morphologic change of Candida albicans under the experimental conditions. Disk diffusion method was used to verify the inhibitory effects of 3-oxo-C12-HSL on morphologic change of Candida albicans. The morphologic changes of Candida albicans being co-cultured with different Pseudomonas aeruginosa strains(pvdQ high expression strain and the wild strain PAODwere observed. Results A total of 400 μg Pseudomonas aeruginosa signal molecule 3-oxo-C12-HSL could completely inhibit the morphologic change of Candida albicans. Both pvdQ high expression strain and the wild strain PAO1 could inhibit the formation of Candida albicans hyphae. pvdQ high expression strain decreased the inhibiting function of Candida albicans morphologic change compared to the wild strain PAO1. Conclusion By secretion of signaling molecules 3-oxo-C12-HSL, Pseudomonas aeruginosa could inhibit conversion of Candida albicans yeast cells to hyphae. With the increase of pvdQ expression, its inhibition to Candida albicans is reduced. pvdQ gene displays a negative regulatory role in inhibiting morphologic change of Candida albicans by Pseudomonas aeruginosa , which may be related to the 3-oxo-C12-HSL hydrolysis by pvdQ gene.