Escherichia coli avoids high dissolved oxygen stress by activation of SoxRS and manganese-superoxide dismutase.
Escherichia coli avoids high dissolved oxygen stress by activation of SoxRS and manganese-superoxide dismutase.
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大肠杆菌通过激活SOXR和锰 - 羟基歧化酶避免了高溶解的氧气胁迫。
DOI：
10.1186/1475-2859-12-23
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发表时间：
2013-03-12
影响因子：
6.4
通讯作者：
Shiloach J
中科院分区：
文献类型：
--
作者：
Baez A;Shiloach J
据报道，高浓度的活性氧（ROS）会对大肠杆菌细胞造成氧化应激，从而导致生长减少或抑制。这些报告中描述的高ROS浓度是通过将细菌暴露于H2O2和产生超氧化物的化学物质而产生的，这是非生理生长条件。然而，分子氧对氧化应激反应的影响尚未得到评估。由于使用富氧空气是支持大肠杆菌高密度生长的常见策略，因此研究高溶解氧浓度对大肠杆菌生理和生长的影响及其对氧化应激的反应方式非常重要。为了确定氧气浓度升高对大肠杆菌生长特性、特定基因表达和酶活性的影响，当溶解氧 (dO2) 水平从 30% 增加到 300% 时，对亲本菌株和 SOD 缺陷菌株进行了评估。除了呼吸作用和醋酸盐积累曲线暂时降低外，亲本菌株的生长参数没有观察到显着差异。通过转录分析，确定亲本菌株通过激活 SoxRS 调节子来响应氧化应激。然而，在 dO2 转换后，SOD 缺陷菌株激活了 SoxRS 和 OxyR 调节子，但无法恢复其初始生长速度。转录分析和酶活性结果表明，当大肠杆菌暴露于dO2转变时，超氧化物应激调节因子SoxRS被激活并引起超氧化物歧化酶系统的刺激。这使得大肠杆菌能够保护自身免受氧气的中毒作用。 OxyR 保护系统没有被激活，表明 H2O2 没有增加到应激水平。
High concentrations of reactive oxygen species (ROS) were reported to cause oxidative stress to E. coli cells associated with reduced or inhibited growth. The high ROS concentrations described in these reports were generated by exposing the bacteria to H2O2 and superoxide-generating chemicals which are non-physiological growth conditions. However, the effect of molecular oxygen on oxidative stress response has not been evaluated. Since the use of oxygen-enriched air is a common strategy to support high density growth of E. coli, it was important to investigate the effect of high dissolved oxygen concentrations on the physiology and growth of E. coli and the way it responds to oxidative stress. To determine the effect of elevated oxygen concentrations on the growth characteristics, specific gene expression and enzyme activity in E. coli, the parental and SOD-deficient strain were evaluated when the dissolved oxygen (dO2) level was increased from 30% to 300%. No significant differences in the growth parameters were observed in the parental strain except for a temporary decrease of the respiration and acetate accumulation profile. By performing transcriptional analysis, it was determined that the parental strain responded to the oxidative stress by activating the SoxRS regulon. However, following the dO2 switch, the SOD-deficient strain activated both the SoxRS and OxyR regulons but it was unable to resume its initial growth rate. The transcriptional analysis and enzyme activity results indicated that when E. coli is exposed to dO2 shift, the superoxide stress regulator SoxRS is activated and causes the stimulation of the superoxide dismutase system. This enables the E. coli to protect itself from the poisoning effects of oxygen. The OxyR protecting system was not activated, indicating that H2O2 did not increase to stressing levels.
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DOI：
10.1073/pnas.89.13.5892
发表时间：
1992-07-01
影响因子：
11.1
作者：
LIOCHEV, SI;FRIDOVICH, I
通讯作者：
FRIDOVICH, I
影响因子：
3.4
作者：
Castan, A;Näsman, A;Enfors, SO
通讯作者：
Enfors, SO
DOI：
10.1099/00221287-143-12-3795
发表时间：
1997-12-01
期刊：
MICROBIOLOGY-UK
影响因子：
--
作者：
Cunningham, L;Gruer, MJ;Guest, JR
通讯作者：
Guest, JR
DOI：
10.1111/j.1749-6632.1999.tb07814.x
发表时间：
1999-01-01
期刊：
OXIDATIVE/ENERGY METABOLISM IN NEURODEGENERATIVE DISORDERS
影响因子：
--
作者：
Fridovich, I
通讯作者：
Fridovich, I
影响因子：
3.2
作者：
KEYER, K;GORT, AS;IMLAY, JA
通讯作者：
IMLAY, JA