Cellular and metabolic integration of symbiotic organelles in the ciliate Mesodinium rubrum

光合作用生命(植物和藻类)有一个复杂的进化历史，这是由于共生相互作用导致叶绿体(光合器官)在不相关的有机体群体之间转移。虽然有大量证据表明共生在这些进化事件中所起的作用，但关于生物体如何适应变得“绿色”却知之甚少。这个项目将研究获得叶绿体的早期事件，以及有机体如何重组其整个新陈代谢以利用光合作用，尽管缺乏运行光合作用所需的基因。研究人员将专注于一种常见的海洋纤毛虫，这种动物以一种特定的藻类为食，并窃取其细胞器(即细胞器：叶绿体、线粒体和细胞核)。纤毛虫能够将这些细胞器合并到自己的细胞中，甚至在细胞分裂时通过利用暂时被盗的细胞核表达的基因来复制它们。研究人员将使用下一代(转录组学、蛋白质组学、代谢组学)和传统的(显微镜、细胞生理学)技术来发现生物如何适应光合作用的新陈代谢，并将外来细胞器结合到自己的细胞中。研究人员将重点研究纤毛虫如何能够窃取细胞核并促进其基因表达，以及随后蛋白质如何靶向被盗的细胞器，这些细胞器在其细胞内重组。这种外来的核不能在纤毛虫体内分裂，因此必须在细胞分裂后常规地通过取食来代替。这些结果将在共生(包括寄生)的研究中有广泛的应用，并将重塑我们对共生在真核生物进化中的作用的看法。研究人员将与西风教育基金会合作，与学生(8-12年级)合作，扩大海洋科学素养，并教授关于共生的知识。他们还将通过实验室研究项目培训代表性不足的本科生。

Photosynthetic life (plants and algae) has a complex evolutionary history due to symbiotic interactions that have resulted in the transfer of chloroplasts (the photosynthetic organelle) among unrelated groups of organisms. While there is abundant evidence for the role of symbiosis in these evolutionary events, little is known regarding how organisms adapt to become "green". This project will investigate early events in the acquisition of a chloroplast and how an organism has restructured its entire metabolism in order to use photosynthesis, despite lacking the genes necessary to run it. The investigators will focus on a common marine ciliate that is known to feed on one particular group of algae, and steal its cellular machinery (i.e. the organelles: chloroplasts, mitochondria, and nucleus). The ciliate is able to incorporate these organelles into its own cell, and even replicate them as the cell divides, by utilizing genes expressed from the temporary stolen nucleus. The investigators will use next generation (transcriptomics, proteomics, metabolomics) and traditional (microscopy, cell physiology) techniques to discover how organisms can adapt to a photosynthetic metabolism and incorporate foreign organelles into their own cell. The investigators will focus on how the ciliate is able to steal a nucleus and facilitate its gene expression, and the subsequent targeting of proteins back to the stolen organelles that are reorganized within its cell. This foreign nucleus cannot divide in the ciliate, and therefore must be routinely replaced by feeding after the cell divides. These results will have broad applications to studies of symbiosis (including parasitism), and will reshape how we think about the role of symbiosis in eukaryotic evolution. The investigators will work with students (grades 8-12) in collaboration with the Zephyr Education Foundation, to expand marine science literacy and to teach about symbiosis. They will also train under-represented undergraduates through laboratory research projects.