Regulation of tert-Butyl Hydroperoxide Resistance by Chromosomal OhrR in A. baumannii ATCC 19606.
Regulation of tert-Butyl Hydroperoxide Resistance by Chromosomal OhrR in A. baumannii ATCC 19606.
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DOI：
10.3390/microorganisms9030629
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发表时间：
2021-03-18
期刊：
影响因子：
4.5
通讯作者：
Lin GH
中科院分区：
文献类型：
--
作者：
Chen SJ;Shu HY;Lin GH
在这项研究中，我们发现鲍曼不动杆菌ATCC 19606携带两组ohrR-ohr基因，分别编码在染色体DNA和pMAC质粒中。我们发现有或没有pMAC的菌株对有机过氧化氢（OHP）的耐药性没有显著差异。然而，通过将野生型，∆ohrR-C， C代表染色体上的基因，或∆ohrR-C单突变体，或∆ohrR-C，∆ohrR-C双突变体暴露于过氧化叔丁基（tBHP）进行的圆盘扩散试验发现，ohrr -p- ohrp基因，p代表pMAC质粒上的基因，可能能够补充其染色体对应基因的功能。有趣的是，不含pMAC的鲍曼不雅杆菌ATCC 17978中产生的∆ohr-C单突变体在暴露于135 μg的thbhp后表现出指数增长延迟和活力丧失。在对mellonella幼虫进行的存活试验中，这些突变体几乎完全丧失了毒力。通过电泳迁移率转移试验（EMSA），我们发现OhrR-C能够结合染色体和pMAC ohrp基因的启动子区域，但具有不同的亲和力。在大肠杆菌中进行的功能获得实验表明，OhrR-C不仅能够抑制转化的ohrc基因，还可能抑制内源性酶。综上所述，我们的研究结果表明，染色体上的ohrR-C-ohr-C基因是保护鲍曼不动杆菌ATCC 19606免受OHP胁迫的主要系统，但pMAC上的ohrR-p-ohr-p基因可以提供补充保护作用，这些基因之间的相互作用可能影响细菌活力的其他方面，如生长和毒力。
In this study, we show that Acinetobacter baumannii ATCC 19606 harbors two sets of ohrR-ohr genes, respectively encoded in chromosomal DNA and a pMAC plasmid. We found no significant difference in organic hydroperoxide (OHP) resistance between strains with or without pMAC. However, a disk diffusion assay conducted by exposing wild-type, ∆ohrR-C, C represented gene on chromosome, or ∆ohr-C single mutants, or ∆ohrR-C∆ohr-C double mutants to tert-butyl hydroperoxide (tBHP) found that the ohrR-p-ohr-p genes, p represented genes on pMAC plasmid, may be able to complement the function of their chromosomal counterparts. Interestingly, ∆ohr-C single mutants generated in A. baumannii ATCC 17978, which does not harbor pMAC, demonstrated delayed exponential growth and loss of viability following exposure to 135 μg of tBHP. In a survival assay conducted with Galleria mellonella larvae, these mutants demonstrated almost complete loss of virulence. Via an electrophoretic mobility shift assay (EMSA), we found that OhrR-C was able to bind to the promoter regions of both chromosomal and pMAC ohr-p genes, but with varying affinity. A gain-of-function assay conducted in Escherichia coli showed that OhrR-C was not only capable of suppressing transformed ohr-C genes but may also repress endogenous enzymes. Taken together, our findings suggest that chromosomal ohrR-C-ohr-C genes act as the major system in protecting A. baumannii ATCC 19606 from OHP stresses, but the ohrR-p-ohr-p genes on pMAC can provide a supplementary protective effect, and the interaction between these genes may affect other aspects of bacterial viability, such as growth and virulence.
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影响因子：
--
作者：
Ayala A;Muñoz MF;Argüelles S
通讯作者：
Argüelles S
影响因子：
5.2
作者：
BERGOGNEBEREZIN, E;DECRE, D;JOLYGUILLOU, ML
通讯作者：
JOLYGUILLOU, ML
影响因子：
3.1
作者：
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通讯作者：
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影响因子：
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作者：
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通讯作者：
Dhandayuthapani, Subramanian
DOI：
10.1073/pnas.102483199
发表时间：
2002-05-14
影响因子：
11.1
作者：
Fuangthong, M;Helmann, JD
通讯作者：
Helmann, JD