MITOCHONDRIA OF MAMMALIAN PLASMODIUM SPP
MITOCHONDRIA OF MAMMALIAN PLASMODIUM SPP
复制标题
DOI：
10.1017/s0031182000060297
复制
发表时间：
1991-02-01
期刊：
影响因子：
2.4
通讯作者：
BEESLEY, JE
中科院分区：
文献类型：
--
作者：
FRY, M;BEESLEY, JE
从两种哺乳动物疟原虫属、啮齿动物约氏疟原虫和人类恶性疟原虫的红细胞内阶段分离出高度纯化的线粒体组分。 前一种寄生虫的线粒体是冠状的，而后者的线粒体基本上是冠状的。 从两种寄生虫物种中分离的线粒体在大小、形状、基质染色密度和内部结构范围方面是异质的。 通过减少外源细胞色素 c 进行的呼吸测定表明，NADH、α-甘油磷酸和琥珀酸是最有代谢潜力的底物。 此外，脯氨酸、二氢乳清酸和谷氨酸（仅限恶性疟原虫）的氧化率较低。 未使用许多 NAD+ 连接的底物。 细胞色素 c 的 NADH 依赖性还原对鱼藤酮和抗霉素 A 不敏感。富马酸盐抑制细胞色素 c 的 NADH 依赖性还原并刺激 NADH 氧化，表明存在 NADH-富马酸还原酶途径。 标准线粒体电子传递抑制剂（包括许多复合物 III 抑制剂）完全抑制了 α-甘油磷酸或琥珀酸的氧化，尽管与哺乳动物线粒体相比，此类抑制剂（特别是 myxothiazol）所需的浓度相对较高。 连二亚硫酸盐还原减去氧化差异光谱表明两种寄生虫物种的线粒体中都存在细胞色素aa3、b、c和c1，但在约氏疟原虫中细胞色素与蛋白质的比率较高。 从任一物种中新鲜分离的线粒体以α-甘油磷酸或琥珀酸作为底物仅表现出较低的呼吸控制率。 这种线粒体中明显缺乏呼吸链“位点 I”可能意味着 NADH-富马酸还原酶可以重新氧化线粒体 NADH。
Highly purified mitochondrial fractions have been isolated from the intraerythrocytic stages of two mammalian Plasmodium spp., Plasmodium yoelii of rodents and Plasmodium falciparum of man. Mitochondria of the former parasite are cristate whereas those of the latter are essentially acristate. Isolated mitochondria from both parasite species were heterogeneous with respect to size, shape, density of matrix staining and extent of internal structure. Respiratory assay, by reduction of exogenous cytochrome c, showed NADH, alpha-glycerophosphate and succinate to be the substrates with the greatest potential for metabolism. Additionally, proline, dihydroorotate and glutamate (P. falciparum only) were oxidized at low rates. A number of NAD+-linked substrates were not utilized. The NADH-dependent reduction of cytochrome c was insensitive to rotenone and antimycin A. Fumarate inhibited the NADH-dependent reduction of cytochrome c and stimulated the oxidation of NADH, suggestive of an NADH-fumarate reductase pathway. Oxidation of either alpha-glycerophosphate or succinate was fully inhibited by standard mitochondrial electron transport inhibitors, including a number of Complex III inhibitors, although the concentrations required of such inhibitors (notably myxothiazol) were relatively high compared to mammalian mitochondria. Dithionite-reduced minus oxidized difference spectra indicated the presence of cytochromes aa3, b, c and c1 in mitochondria of both parasite species, but at a higher cytochrome to protein ratio in P. yoelii. Freshly isolated mitochondria from either species exhibited only low respiratory control ratios with alpha-glycerophosphate or succinate as substrates. The apparent absence of a respiratory chain 'Site I' in such mitochondria may mean that NADH-fumarate reductase serves to reoxidize mitochondrial NADH.