Metabolic communication in secondary endosymbionts

次级内共生体的代谢通讯

• 批准号: 5435011
• 负责人: Professor Dr. Ekkehard Neuhaus
• 金额: --
• 依托单位: Fachgebiet Pflanzenphysiologie
• 依托单位国家: 德国
• 项目类别: Priority Programmes
• 财政年份: 2004
• 资助国家: 德国
• 起止时间: 2003-12-31 至 2008-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/5435011?language=en
• 关键词: Metabolic; communication; secondary; endosymbionts

Guillardia theta belongs to a group of protists named cryptomonads that evolved by engulfment of an eukaryotic alga into a heterotrophic eukaryote. During the establishment of this consortium the symbiont has been reduced to a four-membrane exhibiting plastid still harbouring a vestigial nucleus in the periplastid space. We demonstrated that the former endosymbiont and the host perform a unique spatial separation of primary carbohydrate metabolism: Photosynthetically synthesized triose phosphates leave the chloroplast and cross the four envelope membranes into the cytosol, become converted to UDP-Glucose subsequently re-imported into the periplastid space for starch synthesis. For this complex metabolic route the cryptomonad use both, a novel type of plastidic triose-phosphate transporter and a so far unknown UDP-Glucose importer. Our aim is to characterize carriers and enzymes involved in this unique physiological communication in cryptomonads. This analysis will allow understanding a complex metabolic network as a consequence of secondary endosymbiosis. In addition, these studies will also promote the understanding of the metabolic interaction in human pathogenic apicomplexa in more detail. Latter contain an apicoplast also generated by a secondary endosymbiosis and also essential for primary metabolism.

Guillardia theta属于一组被称为隐单胞菌的原生生物，它通过吞噬真核藻类进化成异养真核生物。在这个联合体的建立过程中，共生体已经减少到一个四膜，展示质体，在质体周围空间仍然有一个退化的核。我们证明了前内共生体和宿主在初级碳水化合物代谢中进行了独特的空间分离：光合作用合成的磷酸三糖离开叶绿体，穿过四层包膜进入细胞质，转化为udp -葡萄糖，然后再输入到质体周围空间进行淀粉合成。对于这种复杂的代谢途径，隐单胞菌同时使用一种新型的可塑磷酸三糖转运体和一种迄今未知的磷酸三糖转运体。我们的目的是表征参与隐孢子虫这种独特的生理通讯的载体和酶。这种分析将允许理解复杂的代谢网络作为次生内共生的结果。此外，这些研究也将促进对人类致病性尖丛代谢相互作用的更详细的了解。后者含有一个顶质体，也是由次生内共生产生的，也是初级代谢所必需的。