首页 | 本学科首页   官方微博 | 高级检索  
     


Cytochrome and Alternative Pathway Respiration during Transient Ammonium Assimilation by N-Limited Chlamydomonas reinhardtii
Authors:Weger H G  Chadderton A R  Lin M  Guy R D  Turpin D H
Affiliation:Department of Biology, Queen's University, Kingston, Ontario, Canada K7L 3N6.
Abstract:Mass spectrometric analysis of gas exchange in light and dark by N-limited cells of Chlamydomonas reinhardtii indicated that ammonium assimilation was accompanied by an increase in respiratory carbon flow to provide carbon skeletons for amino acid synthesis. Tricarboxylic acid (TCA) cycle carbon flow was maintained by the oxidation of TCA cycle reductant via the mitochondrial electron transport chain. In wild-type cells, inhibitor studies and 18O2 discrimination experiments indicated that respiratory electron flow was mediated entirely via the cytochrome pathway in both the light and dark, despite a large capacity for the alternative pathway. In a cytochrome oxidase deficient mutant, or in wild-type cells in the presence of cyanide, the alternative pathway could support the increase in TCA cycle carbon flow. These different mechanisms of oxidation of TCA cycle reductant were reflected by the much greater SHAM sensitivity of ammonium assimilation by cytochrome oxidase-deficient cells as compared to wild type.
Keywords:
本文献已被 PubMed 等数据库收录!
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号