Laboratorio de Parasitología, Departamento de Microbiología y Parasitología, Instituto de Investigación y Análisis Alimentarios, c/ Constantino Candeira s/n, 15782, Universidad de Santiago de Compostela; Santiago de Compostela (La Coruña, Spain).
Departamento de Biología Celular y Ecología; Universidad de Santiago de Compostela; Santiago de Compostela, (La Coruña, Spain).
Protist. 2013 Nov;164(6):824-36. doi: 10.1016/j.protis.2013.09.003. Epub 2013 Oct 11.
The presence of an alternative oxidase (AOX) in the mitochondria of the scuticociliate P. dicentrarchi was investigated. The mitochondrial oxygen consumption was measured in the presence of KCN, an inhibitor of cytochrome pathway (CP) respiration and salicylhydroxamic acid (SHAM), a specific inhibitor of alternative pathway (AP) respiration. AOX expression was monitored by western blotting with an AOX polyclonal antibody. The results showed that P. dicentrarchi possesses a branched mitochondrial electron transport chain with both cyanide-sensitive and -insensitive oxygen consumption. Mitochondrial respiration was partially inhibited by cyanide and completely inhibited by the combination of cyanide and SHAM, which is direct evidence for the existence of an AP in this ciliate. SHAM significantly inhibited in vitro growth of trophozoites both under normoxic and hypoxic conditions. AOX is a 42kD monomeric protein inducible by hypoxic conditions in experimental infections and by CP inhibitors such as cyanide and antimycin A, or by AP inhibitors such as SHAM. CP respiration was greatly stimulated during the exponential growth phase, while AP respiration increased during the stationary phase, in which AOX expression is induced. As the host does not possess AOX, and because during infection P. dicentrarchi respires via AP, it may be possible to develop inhibitors targeting the AP as a novel anti-scuticociliate therapy.
研究了双核草履虫线粒体中替代氧化酶（AOX）的存在。在氰化物（CP 呼吸抑制剂）和水杨羟肟酸（SHAM，AP 呼吸特异性抑制剂）存在的情况下测量线粒体耗氧量。通过用 AOX 多克隆抗体进行 Western blot 监测 AOX 的表达。结果表明，双核草履虫具有分支的线粒体电子传递链，具有氰化物敏感和不敏感的耗氧量。线粒体呼吸被氰化物部分抑制，被氰化物和 SHAM 的组合完全抑制，这是该纤毛虫中存在 AP 的直接证据。SHAM 在常氧和缺氧条件下均显著抑制滋养体的体外生长。AOX 是一种 42kD 的单体蛋白，可在实验感染和 CP 抑制剂（如氰化物和抗霉素 A）或 AP 抑制剂（如 SHAM）诱导的缺氧条件下诱导。CP 呼吸在指数生长阶段大大增加，而 AP 呼吸在静止阶段增加，此时诱导 AOX 表达。由于宿主不具有 AOX，并且由于在感染期间双核草履虫通过 AP 呼吸，因此有可能开发针对 AP 的抑制剂作为新型抗纤毛虫治疗方法。
