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Changes and Their Control Mechanisms of Mitochondrial Electron-Transport Components During Ascaris Life Cycle

蛔虫生命周期线粒体电子传递成分的变化及其控制机制

基本信息

批准号：
01570223
负责人：
TAKAMIYA Shinzaburo
金额：
$ 1.34万
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：
1989
资助国家：
日本
起止时间：
1989 至 1990
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-01570223/
关键词：
Ascaris Mitochondria Respiratory chain Complex II Life cycle Cytochrome Larva Quinone ミトクロム

项目摘要

1. The primary structure of the flavin-bound tryptic peptide from the Fp subunit of Ascaris adult complex II was determined and found to be highly similar to those of the corresponding flavin-binding regions of bovine heart and bacterial Fp subunits.The Ascaris Fp subunit was shown to contain two regions exhibiting striking sequence similarity to the segments interacting with the AMP moiety of FAD in bacterial Fp subunits.2. To elucidate mechanisms of aerobic-anaerobic respiratory transition during development of Ascaris nematode, the larval respiratory chain and its complex II (succinate-ubiquinone oxidoreductase) have been characterized in the isolated mitochondria by spectrophotometry, immunoblotting using anti adlt complex II antibodies and determination of quinones.The results obtained showed that L_2 larvae were the most aerobic among stages studied and the larval complex II was different from the adults counterpart. Furthermore, evidence showing biosynthetic conversion of quinones during development was obtained.3. Oxidation-reduction midpoint potentials (Ems) were determined at pH 7.0 for cytochromes in the anaerobic respiratory chain of Ascaris mitochondria by redox titration techniques.Cytochrome b_<558>, which is associated with complex II that functions as fumarate reductase in the terminal step of the respiratory chain, was shown to have an Em of -34 mV in the isolated complex II and -54 mV in mitochondria. These values are much higher than the value reported for mammalian cytochrome b_<560> of complex II, showing a unique feature of Ascaris cytochrome b_<558>.

1.测定了蛔虫成虫复合体II的Fp亚基的黄素结合胰蛋白酶多肽的一级结构，发现其与牛心和细菌Fp亚基的相应黄素结合区的一级结构高度相似；蛔虫Fp亚基的两个区域与细菌Fp亚基中与AMP部分相互作用的片段具有显著的序列相似性。为了阐明蛔虫发育过程中有氧-无氧呼吸转换的机制，采用分光光度法、抗Adlt复合体II抗体免疫印迹和苯二酚类化合物测定等方法对线虫幼虫呼吸链及其复合体II(琥珀酸-泛醌氧化还原酶)进行了研究。结果表明，在所研究的各个阶段中，L_2幼虫的呼吸链最需氧，且幼虫复合体II有别于成虫。此外，还获得了在发育过程中苯二酚的生物合成转化的证据。用氧化还原滴定技术测定了pH 7.0条件下蛔虫线粒体厌氧呼吸链细胞色素的氧化还原中点电位(EMS)，结果表明，与呼吸链末端富马酸还原酶相关的细胞色素b_&lt；558&gt；在分离的复合体II中的氧化还原中点电位为-34 mV，线粒体中的氧化还原中点电位为-54 mV。这些值远高于报道的哺乳动物细胞色素560&gt；复合体II的值，显示了蛔虫细胞色素b_&lt；558&gt；的独特特征。