Center for Tropical and Emerging Global Diseases & Department of Cellular Biology, University of Georgia, 500 D.W. Brooks Drive, Athens, GA 30602, USA.
Curr Opin Microbiol. 2013 Aug;16(4):452-8. doi: 10.1016/j.mib.2013.07.003. Epub 2013 Aug 5.
The apicoplast and the mitochondrion of Apicomplexa cooperate in providing essential metabolites. Their co-evolution during the ancestral acquisition of a plastid and subsequent loss of photosynthesis resulted in divergent metabolic pathways compared with mammals and plants. This is most evident in their chimerical haem synthesis pathway. Toxoplasma and Plasmodium mitochondria operate canonical tricarboxylic acid (TCA) cycles and electron transport chains, although the roles differ between Toxoplasma tachyzoites and Plasmodium erythrocytic stages. Glutamine catabolism provides TCA intermediates in both parasites. Isoprenoid precursor synthesis is the only essential role of the apicoplast in Plasmodium erythrocytic stages. An apicoplast-located fatty acid synthesis is dispensable in these stages, which instead predominantly salvage fatty acids, while in Plasmodium liver stages and in Toxoplasma tachyzoites fatty acid synthesis is an essential role of the plastid.
顶复门生物的顶质体和线粒体在提供必需代谢物方面进行合作。它们在祖先获得质体和随后失去光合作用的过程中共同进化，导致与哺乳动物和植物相比，代谢途径存在差异。这在它们的嵌合血红素合成途径中最为明显。刚地弓形虫和疟原虫的线粒体都有典型的三羧酸（TCA）循环和电子传递链，尽管在刚地弓形虫速殖子和疟原虫红细胞阶段的作用有所不同。谷氨酰胺分解代谢为两种寄生虫提供 TCA 中间体。异戊烯基前体合成是顶质体在疟原虫红细胞阶段的唯一必需功能。在这些阶段，质体定位的脂肪酸合成是可有可无的，取而代之的是主要回收脂肪酸，而在疟原虫肝阶段和刚地弓形虫速殖子中，脂肪酸合成是质体的必需功能。
