Novel ultrastructural systems in eukaryotic cells: predators, parasites and plastids

30多亿年来，微生物在纯粹的丰富性和多样性方面一直主导着地球，但在所有现存的有机体中，微生物的基本和创新特性是最不被了解的。微型真核生物在形态和遗传上是复杂的，具有细胞核、内膜系统、共生获得的细胞器和复杂的细胞骨架，支持大量特殊的细胞延伸和行为。尽管每个微型真核生物只由一个细胞组成，但它们本身就是一个宇宙，最近我们对这些生物的理解取得的进展，极大地改变了人们长期以来对细胞多样性的看法。因此，拟议的研究计划旨在探索这个陌生的世界，以帮助揭开地球上生命的总体构成、相互关系和历史。单个项目将跨越真核生物多样性的极其广泛的样本，以解决大规模的细胞特征进化模式。该研究计划将继续并行研究四类主要的微型真核生物，它们涵盖了地球上最不同的三种真核生命模式：捕食、光自养和寄生。海洋捕食性鞭毛虫，如真鞭毛虫、甲藻和冷冻单胞藻的独立但相应的形态变化模式，是研究细胞进化中的制约因素和重复出现的创新的理想比较系统。第四类微型真核生物提供了令人信服的见解，揭示了生命史上最神秘的进化转变之一：专性细胞内(顶复合体)寄生虫来自自由生活的光自养祖先。尽管作为人类和家畜的病原体(如疟原虫和弓形虫)而臭名昭著，但大多数顶端复合体多样性正在世界海洋中蓬勃发展。顶端复合体的起源和早期进化将通过探索海洋纤毛虫的多样性和分子系统学来解决，海洋纤毛虫是一种大型的动态寄生虫，生活在海洋无脊椎动物和昆虫的细胞外空间。

For over 3 billion years, microbes have dominated the planet in terms of pure abundance and diversity, yet the fundamental and innovative properties of microbes are the least understood of all extant organisms. Micro-eukaryotes are morphologically and genetically complex, having nuclei, endomembrane systems, symbiotically acquired organelles and elaborate cytoskeletons supporting a vast array of specialized cell extensions and behaviors. Despite being composed of only a single cell, each micro-eukaryote is a universe in itself, and recent advances in our understanding of these organisms have dramatically altered long-held views about the diversity of cells. Accordingly, the proposed research program is designed to explore this foreign world in order to help unravel the total composition, interrelationships and history of life on earth. Individual projects will span an extremely broad sampling of eukaryotic diversity in order to resolve large-scale patterns of cell character evolution. The research program will continue to study, in parallel, four main groups of micro-eukaryotes that encompass what are arguably the three most dissimilar modes of eukaryotic life on the planet: predation, photoautotrophy, and parasitism. The independent but corresponding patterns of morphological change in marine predatory flagellates, such as euglenids, dinoflagellates and cryomonads, represent an ideal comparative system for investigating the constraints and reoccurring innovations in cell evolution. The fourth group of micro-eukaryotes offers compelling insights into one of the most enigmatic evolutionary transformations in the history of life: the origin of obligate intracellular (apicomplexan) parasites from free-living, photoautotrophic ancestors. Despite being infamous as pathogens of humans and livestock (e.g. Plasmodium and Toxoplasma), most of apicomplexan diversity is thriving in the world's oceans. The origin and early evolution of apicomplexans will be addressed by exploring the diversity and molecular phylogeny of marine gregarines, which are large and dynamic parasites that inhabit the extracellular spaces of marine invertebrates and insects.