The evolution of reduced microbial killing.
The evolution of reduced microbial killing.
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DOI：
10.1093/gbe/evp042
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发表时间：
2009-10-20
影响因子：
3.3
通讯作者：
Riley MA
中科院分区：
文献类型：
--
作者：
Vriezen JA;Valliere M;Riley MA
细菌参与了一场永无止境的军备竞赛，它们争夺有限的资源和利基空间。这种激烈的相互作用的结果是发展出强大的生物武器库。也许其中研究最多的是大肠杆菌素，一种由大肠杆菌产生并对大肠杆菌有活性的基于质粒的毒素。本研究旨在探索大肠杆菌素产生菌在连续转移进化过程中的分子响应。当大肠杆菌素在没有目标存在的情况下产生时，会发生什么样的进化变化？在没有目标的情况下还能保持杀伤力吗？为了解决这些和其他问题，大肠杆菌素菌株和非大肠杆菌素的祖先进化了253代。在整个实验过程中取样并测试杀伤能力。到第38次转移时，在产大肠杆菌素菌株中观察到杀灭能力降低和适合度增加。令人惊讶的是，大肠杆菌素质粒的DNA序列测定显示质粒序列没有变化。然而，一组染色体编码的基因座经历了基因表达的变化，这与杀伤减少呈正相关。最显着的表达变化中观察到的DNA修复基因（这是下调的进化株），镁离子摄取基因（这是上调），晚期原噬菌体基因（这是上调）。这些结果表明，大肠杆菌素生产的进化压力的微调反应，涉及的基因比预期的要多得多。
Bacteria engage in a never-ending arms race in which they compete for limited resources and niche space. The outcome of this intense interaction is the evolution of a powerful arsenal of biological weapons. Perhaps the most studied of these are colicins, plasmid-based toxins produced by and active against Escherichia coli. The present study was designed to explore the molecular responses of a colicin-producing strain during serial transfer evolution. What evolutionary changes occur when colicins are produced with no target present? Can killing ability be maintained in the absence of a target? To address these, and other, questions, colicinogenic strains and a noncolicinogenic ancestor were evolved for 253 generations. Samples were taken throughout the experiment and tested for killing ability. By the 38th transfer, a decreased killing ability and an increase in fitness were observed in the colicin-producing strains. Surprisingly, DNA sequence determination of the colicin plasmids revealed no changes in plasmid sequences. However, a set of chromosomally encoded loci experienced changes in gene expression that were positively associated with the reduction in killing. The most significant expression changes were observed in DNA repair genes (which were downregulated in the evolved strains), Mg ion uptake genes (which were upregulated), and late prophage genes (which were upregulated). These results indicate a fine-tuned response to the evolutionary pressures of colicin production, with far more genes involved than had been anticipated.
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影响因子：
64.8
作者：
Kirkup, BC;Riley, MA
通讯作者：
Riley, MA
影响因子：
2.9
作者：
LENSKI, RE;ROSE, MR;TADLER, SC
通讯作者：
TADLER, SC
影响因子：
2.8
作者：
Gordon, DM;Riley, MA
通讯作者：
Riley, MA
影响因子：
3.2
作者：
Cooper, VS;Schneider, D;Lenski, RE
通讯作者：
Lenski, RE
影响因子：
3.3
作者：
Castric, V;Bonney, F;Bernatchez, L
通讯作者：
Bernatchez, L