Many studies have examined the role that conjugation plays in disseminating antibiotic resistance genes in bacteria. However, relatively little research has quantitively examined and modeled the dynamics of conjugation under growing and nongrowing conditions beyond a couple of hours. We therefore examined growing and nongrowing cultures of Escherichia coli over a 24-h period to understand the dynamics of bacterial conjugation in the presence and absence of antibiotics with pUUH239.2, an IncFII plasmid containing multiantibiotic- and metal-resistant genes. Our data indicate that conjugation occurs after E. coli cells divide and before they have transitioned to a nongrowing phase. The result is that there is only a small window of opportunity for E. coli to conjugate with pUUH239.2 under both growing and nongrowing conditions. Only a very small percentage of the donor cells likely are capable of even undergoing conjugation, and not all transconjugants can become donor cells due to molecular regulatory controls and not being in the correct growth phase. Once a growing culture enters stationary phase, the number of capable donor cells decreases rapidly and conjugation slows to produce a plateau. Published models did not provide accurate descriptions of conjugation under nongrowing conditions. We present here a modified modeling approach that accurately describes observed conjugation behavior under growing and nongrowing conditions.

中文翻译：

---

带有IncFII质粒的大肠杆菌K-12菌株的缀合窗口。

许多研究已经检验了缀合在细菌中传播抗生素抗性基因中的作用。然而，相对很少的研究定量地研究和模拟了生长和非生长条件下超过几个小时的结合动力学。因此，我们在24小时内检查了大肠杆菌的生长和非生长培养，以了解在存在和不存在带有pUUH239.2的抗生素的情况下细菌结合的动力学，pUUH239.2是一种含有多抗生素和金属耐药基因的IncFII质粒。我们的数据表明，缀合发生在大肠杆菌细胞分裂后和过渡到非生长期之前。结果是大肠杆菌的机会很小在生长和不生长条件下都与pUUH239.2结合。只有很小百分比的供体细胞甚至能够进行缀合，并且由于分子调节控制并且不是处于正确的生长阶段，并非所有的转缀合物都可以成为供体细胞。一旦生长的培养物进入稳定期，有能力的供体细胞数量迅速减少，结合变慢，从而产生平台。在非生长条件下，已发表的模型没有提供对结合的准确描述。我们在这里提出一种修改后的建模方法，可以准确地描述在增长和不增长条件下观察到的共轭行为。