A theoretical and empirical investigation of the invasion dynamics of colicinogeny
A theoretical and empirical investigation of the invasion dynamics of colicinogeny
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DOI：
10.1099/13500872-145-3-655
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发表时间：
1999-03-01
期刊：
影响因子：
2.8
通讯作者：
Riley, MA
中科院分区：
文献类型：
--
作者：
Gordon, DM;Riley, MA
建立了一个数学模型来描述在连续转移培养条件下产生结肠素的种群和对结肠素敏感的种群的繁殖动态。此外，还对E colicin组的6个代表菌株进行了一系列的体外侵袭实验，并对菌株的生长速度和产Colicin特性进行了估计。不同菌株之间的生长率差异高达44%。不同菌株的裂解率有14倍的差异，每个裂解细胞产生的结肠素的量差异高达10倍。体外连续转移侵袭实验表明，无论初始频率如何，所有产结肠素菌株都成功地置换了敏感细胞群。随着产生结肠粘连素菌群初始频率的增加，对粘菌素敏感的细胞群被取代所需的时间减少，产生更高效价的粘菌素的菌株往往更快地取代敏感菌株。总体而言，理论模型很好地描述了结肠素产生菌入侵的观察动态。然而，尽管不同菌株的生长速度和产结肠素特性有很大差异，但观察或预测的6株产结肠素菌株在侵袭动态上的差异相对较小。这些结果表明，不同产生结肠素的菌株的特性不能解释不同细菌自然种群中不同结肠素相对丰度的广泛差异。
A mathematical model describing the dynamics of a colicinogenic and a colicin-sensitive population propagated under serial transfer culture conditions was formulated. In addition, a series of in vitro invasion experiments using six representatives of the E colicin group was undertaken, together with the estimation of the growth rates and colicinogenic characteristics of the strains. Growth rates among the strains varied by up to 44%. There were 14-fold differences among strains in their lysis rates and there were up to 10-fold differences in the amount of colicin produced per lysed cell. The in vitro serial transfer invasion experiments revealed that regardless of initial frequency all colicinogenic strains succeeded in displacing the sensitive cell populations. The amount of time required for the colicin-sensitive cell population to be displaced declined as the initial frequency of the colicinogenic population increased and strains producing higher titres of colicin tended to displace the sensitive strain more rapidly. Overall, the observed dynamics of the invasion of colicinogenic strains was adequately described by the theoretical model. However, despite there being substantial differences among the strains in their growth rates and colicinogenic characteristics there were relatively few differences, observed or predicted, in the invasion dynamics of the six colicinogenic strains. These results suggest that the characteristics of different colicinogenic strains cannot be used to explain the extensive variation in the relative abundance of different colicins in natural populations of bacteria.