Yeast flavohemoglobin (Yhb1p) plays a pivotal role in NO(*) detoxification and has also been implicated in oxidative/reductive stress responses. In this study, we have used a YHB1-GFP reporter expressing a full-length chromosome-tagged Yhb1-GFP fusion protein to monitor changes in flavohemoglobin levels after cell treatment with oxidants, antioxidants and nitric oxide donors. Only nitric oxide donors were found to induce a dose-dependent increase in Yhb1-GFP expression while hydrogen peroxide, menadione and diamide caused a moderate diminution of YHB1-GFP fluorescence. Additionally, the levels of endogenous and hydroperoxide-induced ROS production in the Deltayhb1 mutant were comparable to those in the isogenic wild-type strain. Although peroxides increased NO(*) generation while nitrite and nitric oxide donors augmented ROS levels in yeast cells, their effects were generally not more pronounced in Deltayhb1 than in wild-type cells. Taken together, these data suggest that yeast flavohemoglobin does not contribute to cross-protection against oxidative and nitrosative stress.

中文翻译：

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YHB1-GFP报告基因在酵母中检测亚硝化应激的应用。

酵母黄素血红蛋白（Yhb1p）在NO（*）排毒中起着关键作用，并且还涉及氧化/还原应激反应。在这项研究中，我们使用YHB1-GFP报告基因表达全长染色体标记的Yhb1-GFP融合蛋白来监测用氧化剂，抗氧化剂和一氧化氮供体处理细胞后黄素血红蛋白水平的变化。发现仅一氧化氮供体诱导Yhb1-GFP表达的剂量依赖性增加，而过氧化氢，甲萘醌和二酰胺则引起YHB1-GFP荧光的中等减弱。此外，Deltayhb1突变体中内源性和氢过氧化物诱导的ROS产生水平与等基因野生型菌株相当。尽管过氧化物会增加NO（*）的生成，而亚硝酸盐和一氧化氮供体会增加酵母细胞中的ROS水平，它们的作用通常在Deltayhb1中没有比在野生型细胞中更明显。综上所述，这些数据表明酵母黄素血红蛋白对交叉抗氧化和亚硝化应激没有帮助。