title: Tetrahydropteridines possess antioxidant roles to guard against glucose-induced oxidative stress in Dictyostelium discoideum.
abstract: Glucose effects on the vegetative growth of Dictyostelium discoideum Ax2 were studied by examining oxidative stress and tetrahydropteridine synthesis in cells cultured with different concentrations (0.5X, 7.7 g L(-1); 1X, 15.4 g L(-1); 2X, 30.8 g L(-1)) of glucose. The growth rate was optimal in 1X cells (cells grown in 1X glucose) but was impaired drastically in 2X cells, below the level of 0.5X cells. There were glucose-dependent increases in reactive oxygen species (ROS) levels and mitochondrial dysfunction in parallel with the mRNA copy numbers of the enzymes catalyzing tetrahydropteridine synthesis and regeneration. On the other hand, both the specific activities of the enzymes and tetrahydropteridine levels in 2X cells were lower than those in 1X cells, but were higher than those in 0.5X cells. Given the antioxidant function of tetrahydropteridines and both the beneficial and harmful effects of ROS, the results suggest glucose-induced oxidative stress in Dictyostelium, a process that might originate from aerobic glycolysis, as well as a protective role of tetrahydropteridines against this stress.
authors: FIRST Research Group, School of Biological Sciences, Inje University, Kimhae 621-749, Korea.
authors: Seon-Ok
authors: SO
authors: Park
authors: Hye-Lim
authors: HL
authors: Kim
authors: Soo-Woong
authors: SW
authors: Lee
authors: Young Shik
authors: YS
authors: Park
mesh_terms: D000975:Antioxidants / Q000378:metabolism*; D004023:Dictyostelium / Q000187:drug effects* / Q000254:growth & development; D006136:GTP Cyclohydrolase / Q000378:metabolism; D005947:Glucose / Q000494:pharmacology*; D006019:Glycolysis; D008928:Mitochondria / Q000378:metabolism; D018384:Oxidative Stress / Q000187:drug effects*; D011621:Pteridines / Q000378:metabolism*; D012333:RNA, Messenger / Q000378:metabolism; D017382:Reactive Oxygen Species / Q000378:metabolism; D013762:Tetrahydrofolate Dehydrogenase / Q000378:metabolism
chemical_list: D000975:Antioxidants; D011621:Pteridines; D012333:RNA, Messenger; D017382:Reactive Oxygen Species; C045357:5,6,7,8-tetrahydropteridine; D013762:Tetrahydrofolate Dehydrogenase; D006136:GTP Cyclohydrolase; D005947:Glucose