Oxidative stress sensitivity of engineered Escherichia coli cells with a reduced genome
Oxidative stress sensitivity of engineered Escherichia coli cells with a reduced genome
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DOI：
10.1111/j.1574-6968.2011.02331.x
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发表时间：
2011-09-01
影响因子：
2.1
通讯作者：
Kato, Jun-ichi
中科院分区：
文献类型：
--
作者：
Iwadate, Yumi;Honda, Hirofumi;Kato, Jun-ichi
构建基因组减少的工程细菌细胞可以研究野生型菌株和衍生物中可能隐蔽的分子机制。此前，通过组合大的染色体缺失构建了缺失29.7%的亲本染色体的大肠杆菌大规模联合缺失突变株。在这项工作中，我们改进了进行无标记染色体缺失的系统，并获得了基因组缺失高达38.9%的亲本染色体的突变体。虽然大规模缺失突变体具有抗氧化胁迫所需的基因，包括超氧化物歧化酶、过氧化氢酶和rpos，但它们对甲萘二酮敏感，甲萘二酮在稳定期诱导活性氧产生。较小的基因组大小并不一定与对甲奈二酮更敏感相关，因为几个缺失较大的突变体对甲奈二酮更具抗药性。突变株对甲萘二酮的敏感性取决于其在有氧或厌氧条件下生长，表明甲萘二酮抗性的机制取决于生长介质的氧分压。对大规模缺失突变体的进一步分析应该有助于确定对细胞防御氧化应激至关重要的调控网络。
The construction of engineered bacterial cells with a reduced genome allows the investigation of molecular mechanisms that may be cryptic in wild-type strains and derivatives. Previously, a large-scale combined deletion mutant of Escherichia coli that lacked 29.7% of the parental chromosome was constructed by combining large chromosome deletions. In this work, we improved the system for making markerless-chromosomal deletions and obtained mutants with a genome that lacked up to 38.9% of the parental chromosome. Although the large-scale deletion mutants possessed genes needed for resistance to oxidative stress, including superoxide dismutase, catalase, and RpoS, they were sensitive to menadione, which induces reactive oxygen species during stationary phase. Small genome size did not necessarily correlate with greater sensitivity to menadione as several mutants with large deletions were more resistant to menadione. The sensitivity to menadione depended on whether the mutants were grown aerobically or anaerobically, suggesting that the mechanism governing menadione resistance depended on the oxygen tension of the growth medium. Further analysis of the large-scale deletion mutants should help identify the regulatory networks that are important for cellular defense against oxidative stress.