Plasmid stability is enhanced by higher-frequency pulses of positive selection.
Plasmid stability is enhanced by higher-frequency pulses of positive selection.
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阳性选择的高频脉冲增强了质粒稳定性。
DOI：
10.1098/rspb.2017.2497
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发表时间：
2018-01-10
期刊：
影响因子：
--
通讯作者：
Harrison E
中科院分区：
文献类型：
--
作者：
Stevenson C;Hall JPJ;Brockhurst MA;Harrison E
原生质体通过在谱系之间共享重要的生态特征来加速细菌的适应。然而，解释细菌种群中质粒的稳定性是具有挑战性的，因为它们的相关成本。以往的理论和实验研究表明，脉冲正选择可能解释质粒稳定性，有利于基因的流动性和促进补偿性进化，改善质粒成本。在这里，我们测试脉冲阳性选择的频率如何影响汞抗性质粒pQBR 103在荧光假单胞菌SBW 25的实验群体中的动力学。质粒动力学根据Hg 2+阳性选择的频率而变化：在没有Hg 2+的情况下，质粒下降到低频率，而Hg 2+选择的脉冲允许质粒扫到高流行率。补偿进化，以改善质粒携带的成本是广泛的整个范围内的Hg 2+的选择制度，包括恒定和脉冲Hg 2+的选择。与理论预测一致，通过接合的基因流动性似乎在促进质粒稳定性方面发挥更大的作用，在低频脉冲的Hg 2+选择下。然而，在去除Hg 2+选择后，在低频脉冲选择方案下进化的质粒随着时间的推移而下降。我们的研究结果表明，时间可变的选择环境，如抗生素治疗过程中产生的，可能有助于解释稳定的移动的质粒编码的电阻。
Plasmids accelerate bacterial adaptation by sharing ecologically important traits between lineages. However, explaining plasmid stability in bacterial populations is challenging owing to their associated costs. Previous theoretical and experimental studies suggest that pulsed positive selection may explain plasmid stability by favouring gene mobility and promoting compensatory evolution to ameliorate plasmid cost. Here we test how the frequency of pulsed positive selection affected the dynamics of a mercury-resistance plasmid, pQBR103, in experimental populations of Pseudomonas fluorescens SBW25. Plasmid dynamics varied according to the frequency of Hg2+ positive selection: in the absence of Hg2+ plasmids declined to low frequency, whereas pulses of Hg2+ selection allowed plasmids to sweep to high prevalence. Compensatory evolution to ameliorate the cost of plasmid carriage was widespread across the entire range of Hg2+ selection regimes, including both constant and pulsed Hg2+ selection. Consistent with theoretical predictions, gene mobility via conjugation appeared to play a greater role in promoting plasmid stability under low-frequency pulses of Hg2+ selection. However, upon removal of Hg2+ selection, plasmids which had evolved under low-frequency pulse selective regimes declined over time. Our findings suggest that temporally variable selection environments, such as those created during antibiotic treatments, may help to explain the stability of mobile plasmid-encoded resistance.
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影响因子：
56.9
作者：
de Visser, JAGM;Zeyl, CW;Lenski, RE
通讯作者：
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影响因子：
3.3
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DOI：
10.1073/pnas.1600974113
发表时间：
2016-07-19
影响因子：
11.1
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5.1
作者：
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通讯作者：
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