Uropathogenic Escherichia coli (UPEC) strain CFT073 is an important pathogenic strain. The genomics analysis reveals that it contains uncommon dual copy gene clusters encoding two types of P fimbriae while demonstrating sequence difference. Previous studies have been carried out to explain the detailed regulatory features, however, the effect of interactions between dual copy homologous pap operons and the significance of this mechanism is not yet satisfactory. In this paper, the authors developed a Markov chain model with population dynamics to examine the effect of the cross-regulation of dual copy pap operons on the distribution and dynamic properties of bacterial population. The results showed that cooperative dual-copy populations confer quicker and better growth in more extensive niche states. This study presents a quantitative analysis of the strategy of pathogen to infect host, thus leads to a better understanding of virulence mechanisms of the CFT073 strain and other pathogens.%致病性大肠杆菌CFT073 (uropathogenic Escherichia coli CFT073)是一种重要的人体病原菌.基因组学研究表明其负责表达P菌毛的pap操纵子存在不寻常的双拷贝现象,且两份拷贝具有一定的差异性.近年来,人们对P菌毛调控系统的分子调控机制获得了一定的认识,但pap操纵子的双拷贝机制及其生物学意义还有待于深入研究.作者首先对双拷贝pap操纵子的调控系统建立Markov链模型,进一步结合种群动力学方法,研究双拷贝相互作用对该菌株种群表型分布演化的影响.模拟结果表明,合作的双拷贝种群在更广泛的环境下具有更强的适应性,并有利于种群更快地建立生存优势.这一研究对致病菌有效感染宿主所采用的策略进行了定量分析,有助于进一步理解CFT073及类似致病菌的致病机制.
展开▼
