Schurig-Briccio Lici A, Farías Ricardo N, Rodríguez-Montelongo Luisa, Rintoul María R, Rapisarda Viviana A
Departamento Bioquímica de la Nutrición, Instituto Superior de Investigaciones Biológicas, Técnicas-Universidad Nacional de Tucumán, San Miguel de Tucumán, Argentina.
Arch Biochem Biophys. 2009 Mar 1;483(1):106-10. doi: 10.1016/j.abb.2008.12.009. Epub 2008 Dec 27.
Escherichia coli gradually decline the capacity to resist oxidative stress during stationary phase. Besides the aerobic electron transport chain components are down-regulated in response to growth arrest. However, we have previously reported that E. coli cells grown in media containing at least 37mM phosphate maintained ndh expression in stationary phase, having high viability and low NADH/NAD(+) ratio. Here we demonstrated that, in the former condition, other aerobic respiratory genes (nuoAB, sdhC, cydA, and ubiC) expression was maintained. In addition, reactive oxygen species production was minimal and consequently the levels of thiobarbituric acid-reactive substances and protein carbonylation were lower than the expected for stationary cells. Interestingly, defense genes (katG and ahpC) expression was also maintained during this phase. Our results indicate that cells grown in high phosphate media exhibit advantages to resist endogenous and exogenous oxidative stress in stationary phase.
大肠杆菌在稳定期抵抗氧化应激的能力逐渐下降。此外，有氧电子传递链成分会因生长停滞而下调。然而，我们之前报道过，在含有至少37mM磷酸盐的培养基中生长的大肠杆菌细胞在稳定期维持ndh表达，具有高活力和低NADH/NAD(+)比率。在此我们证明，在前述条件下，其他有氧呼吸基因（nuoAB、sdhC、cydA和ubiC）的表达得以维持。此外，活性氧的产生极少，因此硫代巴比妥酸反应性物质和蛋白质羰基化水平低于稳定期细胞的预期水平。有趣的是，防御基因（katG和ahpC）的表达在该阶段也得以维持。我们的结果表明，在高磷酸盐培养基中生长的细胞在稳定期表现出抵抗内源性和外源性氧化应激的优势。
