Department of Analytical Biotechnology, Institute of Cell Biology NAS of Ukraine, Lviv, Ukraine.
Curr Microbiol. 2013 Jan;66(1):79-87. doi: 10.1007/s00284-012-0242-0. Epub 2012 Oct 9.
Iron deficiency causes oversynthesis of riboflavin in several yeast species, known as flavinogenic yeasts. Under iron deprivation conditions, Pichia guilliermondii cells increase production of riboflavin and malondialdehyde and the formation of protein carbonyl groups, which reflect increased intracellular content of reactive oxygen species. In this study, we found that P. guilliermondii iron deprived cells showed dramatically decreased catalase and superoxide dismutase activities. Previously reported mutations rib80, rib81, and hit1, which affect repression of riboflavin synthesis and iron accumulation by iron ions, caused similar drops in activities of the mentioned enzymes. These findings could explain the previously described development of oxidative stress in iron deprived or mutated P. guilliermondii cells that overproduce riboflavin. Similar decrease in superoxide dismutase activities was observed in iron deprived cells in the non-flavinogenic yeast Saccharomyces cerevisiae.
缺铁会导致几种酵母物种（称为黄素生成酵母）中核黄素的过度合成。在缺铁条件下，毕赤酵母细胞增加核黄素和丙二醛的产生以及蛋白质羰基的形成，这反映了细胞内活性氧物质含量的增加。在这项研究中，我们发现毕赤酵母缺铁细胞的过氧化氢酶和超氧化物歧化酶活性明显下降。先前报道的突变体 rib80、rib81 和 hit1 影响核黄素合成的抑制和铁离子的积累，导致上述酶活性的类似下降。这些发现可以解释先前描述的铁剥夺或突变的毕赤酵母细胞中过度产生核黄素时发生的氧化应激。在非黄素生成酵母酿酒酵母的缺铁细胞中也观察到超氧化物歧化酶活性的类似下降。
