Czarna Malgorzata, Sluse Francis E, Jarmuszkiewicz Wieslawa
Laboratory of Bioenergetics, Institute of Molecular Biology and Biotechnology, Adam Mickiewicz University, Fredry 10, 61-701 Poznan, Poland.
J Bioenerg Biomembr. 2007 Apr;39(2):149-57. doi: 10.1007/s10863-007-9073-2. Epub 2007 Apr 14.
The alterations in mitochondrial bioenergetics during growth in a batch culture of Acanthamoeba castellanii were studied. The capacity of cytochrome pathway-dependent respiration measured in vitro decreased from the intermediary phase, when cell division slowed down. The pattern of the cytochrome pathway capacity changes was paralleled from the intermediary phase by alterations in the amount of total (and reducible) membranous ubiquinone. These changes were accompanied by a decrease in mitochondrial reactive oxygen species production in vitro (when no energy-dissipating system was active), and almost no change in superoxide dismutase activity and protein level, thus indicating an equivalent need for this enzyme in oxidative stress defence in A. castellanii culture. On the other hand, a decrease in the activity and protein level of alternative oxidase and uncoupling protein was observed in vitro, when cells shifted from the exponential growth phase to the stationary phase. It turned out that the contribution of both energy-dissipating systems in the prevention of mitochondrial reactive oxygen species generation in vivo could lead to its constant level throughout the growth cycle of A. castellanii batch culture. Hence, the observed functional plasticity insures survival of high quality cysts of A. castellanii cells.
研究了卡氏棘阿米巴分批培养生长过程中线粒体生物能量学的变化。体外测定的细胞色素途径依赖性呼吸能力从细胞分裂减缓的中间阶段开始下降。从中间阶段开始，细胞色素途径能力变化模式与总（可还原）膜结合泛醌量的变化平行。这些变化伴随着体外线粒体活性氧产生的减少（当没有能量耗散系统活跃时），超氧化物歧化酶活性和蛋白质水平几乎没有变化，因此表明在卡氏棘阿米巴培养物的氧化应激防御中对该酶有同等需求。另一方面，当细胞从指数生长期转变为稳定期时，体外观察到交替氧化酶和解偶联蛋白的活性和蛋白质水平下降。结果表明，两种能量耗散系统在体内预防线粒体活性氧产生中的作用可导致其在卡氏棘阿米巴分批培养的整个生长周期中保持恒定水平。因此，观察到的功能可塑性确保了卡氏棘阿米巴细胞高质量囊肿的存活。
