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【目的】探索迟缓爱德华菌Lux S/AI-2型密度感应系统关键基因lux S的分布及在不同生长时期的表达特征和生物功能。【方法】克隆迟缓爱德华菌lux S基因,利用生物信息学工具和网络数据库分析该基因序列的特征及编码蛋白的基本特征和保守结构;原核表达Lux S蛋白,纯化后制备抗Lux S的抗体,运用Western-blot技术分析Lux S在不同毒力、不同来源迟缓爱德华菌中的分布情况及在不同生长时期的表达水平;利用抗体中和方法,分析抗Lux S抗体对迟缓爱德华菌生长的影响,探索Lux S是否为信号分子AI-2的特异依赖模式。【结果】克隆到迟缓爱德华菌lux S基因,长度为516 bp,序列分析结果表明,该基因在迟缓爱德华菌属中高度保守;对多株迟缓爱德华菌Lux S蛋白的检测结果表明,该基因在该菌属中普遍存在;对不同生长时期Lux S蛋白的检测结果表明,Lux S蛋白的表达量在迟缓期较低,进入对数生长期逐渐增加,在对数生长后期最大,稳定后期逐渐减少;抗体中和生长试验结果表明,1%抗血清(效价1:40000)能延长迟缓爱德华菌生长的平台期,但对细菌生长无显著影响。【结论】Lux S/AI-2介导的密度感应系统在迟缓爱德华菌中普遍存在;关键基因lux S的序列高度保守,在不同生长时期表达量不一致,在对数生长后期达到峰值。
【Objective】 To explore the distribution of lux S, a key gene of Lux S / AI-2 density-sensitive system, and its expression characteristics and biological functions at different growth stages. 【Method】 Lux S gene was cloned from Agrobacterium tumefaciens. The bioinformatics tools and network database were used to analyze the characteristics of the gene and the basic characteristics and conserved structure of the encoded protein. Lux S protein was expressed in E. coli and purified to prepare anti-Lux S antibody. The distribution of Lux S in different virulence and different sources of Edwardsiella laevigata was analyzed by Western-blot, and the expression of Lux S at different growth stages was analyzed. The effect of anti-Lux S antibody on the growth of E. edulis was analyzed by antibody neutralization method. To explore whether Lux S is a specific dependent mode of signaling molecule AI-2. 【Result】 The results showed that the lux S gene was cloned to 516 bp. The sequence analysis showed that the gene was highly conserved in the genus Edwardsiella. The results showed that the gene was highly expressed in the Lux S gene of many strains of Edwardsiella spp. The results showed that the Lux S protein expression in different growth stages showed that the expression level of Lux S protein was lower in retardation period and gradually increased in logarithmic growth period and was the largest in late logarithmic phase and gradually decreased in late stationary phase The results of antibody neutralization growth test showed that 1% antiserum (titer 1: 40000) prolonged the plateau of growth of Edwardsiella spp., But had no significant effect on the growth of bacteria. 【Conclusion】 The Lux S / AI-2-mediated density-sensing system is ubiquitous in S. edwardsiana. The sequence of the key gene lux S is highly conserved. The expression of Lux S / AI-2 is inconsistent at different growth stages and peaks at the late logarithmic growth phase.