Metabolic networks to combat oxidative stress in Pseudomonas fluorescens
Metabolic networks to combat oxidative stress in Pseudomonas fluorescens
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DOI：
10.1007/s10482-010-9538-x
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发表时间：
2011-03-01
影响因子：
2.6
通讯作者：
Appanna, Vasu D.
中科院分区：
文献类型：
--
作者：
Mailloux, Ryan J.;Lemire, Joseph;Appanna, Vasu D.
氧化应激是好氧生物必须面对的一种不可避免的危险。因此，部署复杂的策略来努力抵御与生活在氧气环境中相关的危险也就不足为奇了。在经典的抗氧化防御机制模型中，强调了各种策略，包括ROS清除系统、NADPH生成酶和DNA修复机制。然而，越来越清楚的是，新陈代谢可能与抗氧化防御密切相关。最近的数据表明，代谢重编程在暴露于氧化应激下的生物体的生存中起着关键作用。在这里，我们描述了荧光假单胞菌，一种代谢多种多样的土壤微生物，如何操纵其代谢网络来努力对抗氧化应激。新陈代谢和抗氧化防御之间存在着复杂的联系。荧光假单胞菌重新调整其代谢过程，以满足其在氧化损伤期间对NADPH的需求。看起来，不同的代谢模块似乎合作在一起，同时微调抗氧化剂NADPH和促氧化剂NADH的水平。吡啶核苷酸代谢产物的这种转变的中心是NAD激酶的增加以及伴随而来的NADP磷酸酶的减少。为了限制NADH的形成，对三羧酸循环进行了调整。这种代谢氧化还原平衡行为似乎提供了一个有效的工具来对抗氧化挑战，并可能是一种比迄今所认识到的更广泛的对抗ROS的策略。
Oxidative stress is an unavoidable peril that aerobic organisms have to confront. Thus, it is not surprising that intricate strategies are deployed in an effort to fend the dangers associated with living in an O-2 environment. In the classical models of anti-oxidative defense mechanisms, a variety of stratagems including the reactive oxygen species (ROS) scavenging systems, the NADPH-generating enzymes and the DNA repair machineries are highlighted. However, it is becoming increasingly clear that metabolism may be intimately involved in anti-oxidative defence. Recent data show that metabolic reprogramming plays a pivotal role in the survival of organisms exposed to oxidative stress. Here, we describe how Pseudomonas fluorescens, the metabolically-versatile soil microbe, manipulates its metabolic networks in an effort to counter oxidative stress. An intricate link between metabolism and anti-oxidative defense is presented. P. fluorescens reconfigures its metabolic processes in an effort to satisfy its need for NADPH during oxidative insult. Seemingly, disparate metabolic modules appear to partner together to concomitantly fine-tune the levels of the anti-oxidant NADPH and the pro-oxidant NADH. Central to this shift in the metabolic production of the pyridine nucleotides is the increase in NAD kinase with the concomitant decrease in NADP phosphatase. The tricarboxylic acid cycle is tweaked in an effort to limit the formation of NADH. This metabolic redox-balancing act appears to afford a potent tool against oxidative challenge and may be a more widespread ROS-combating tactic than hitherto recognized.