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Biochemical studies on aerobic-anaerobic respiratory transition in mitochondria from parasitic helminthes

寄生蠕虫线粒体有氧-无氧呼吸转变的生化研究

基本信息

批准号：
03670201
负责人：
TAKAMIYA Shinzaburo
金额：
$ 1.09万
依托单位：
Juntendo University School of Medicine
依托单位国家：
日本
项目类别：
Grant-in-Aid for General Scientific Research (C)
财政年份：
1991
资助国家：
日本
起止时间：
1991 至 1992
项目状态：
已结题

项目摘要

1. The primary structures of the Ip subunit of complex II of adult Ascaris were determined using peptides separated on Biogel P-60 in the presence of sodium dodecylsulfate. The alanine-threonine cluster, a conserved region in the amino terminus of the mammalian Ip subunit, was found in the Ascaris Ip subunit. Two of the three cystein-rich segments generally conserved in the Ip subunit were sequenced following chemical modification of cystein residues. From a comparative analysis of the sequences, the Ip subunit of complex II in Ascaris adult appears to be more closely related to those of bacterial SDH and mammalian complex II than to that of bacterial FRD, even though Ascaris complex II shows a high FRD activity.2. To elucidate mechanisms of aerobic-anaerobic respiratory transition during development of Ascaris nematode, the larval respiratory chain and its complex II have been characterized in the isolated mitochondria by spectrophotometry, immunoblotting using anti adult complex II antibodies and determination of quinones. The results obtained showed that L2 larvae were the most aerobic among stages studied and the larval complex II was different from the adult counterpart. Furthermore, evidence showing biosynthetic conversion of quinones durig development was obtained.3. Mitochondria from a lung fluke, Paragonimus westermani, were isolated to study the worm respiratory chain. Interestingly, the adult worm mitochondria were shown to possess both aerobic and anaerobic respiratory chains, i. e., cyanide-sensitive succinate oxidase and NADH-fumarate reductase system, respectively. The mitochondria were also found to contain both rhodoquinone-10 and ubiquinone-10.

1.在十二烷基硫酸钠存在下，用生物凝胶P-60分离的多肽测定了成虫复合体II的Ip亚基的一级结构。丙氨酸-苏氨酸簇是哺乳动物Ip亚基氨基末端的一个保守区域，存在于蛔虫Ip亚基中。在Ip亚基中普遍保守的三个富含半胱氨酸的片段中，有两个在半胱氨酸残基被化学修饰后进行了测序。从序列的比较分析，成虫复合体II的Ip亚基与细菌SDH和哺乳动物复合体II的Ip亚基似乎比与细菌FRD的Ip亚基关系更密切，尽管蛔虫复合体II表现出较高的FRD活性。为了阐明蛔虫发育过程中有氧-无氧呼吸转换的机制，用分光光度法、抗成虫复合体II抗体免疫印迹和对苯二酚的测定，对幼虫呼吸链及其复合体II在分离的线粒体中进行了表征。结果表明，在所研究的各个阶段中，L2幼虫是最需氧的，幼虫复合体II与成虫不同。此外，还获得了苯二酚在发育过程中生物合成转化的证据。分离卫氏并殖吸虫肺吸虫线粒体，研究其呼吸链。有趣的是，成虫线粒体同时具有有氧和无氧呼吸链，即氰化物敏感的琥珀酸氧化酶和NADH-富马酸还原酶系统。线粒体还被发现同时含有若丹酚-10和泛醌-10。