DNA replication a checkpoint in regulating development in Myxococcus xanthus

项目摘要：了解单个细胞如何与环境相互作用，以及环境如何塑造和调节细胞生长和分化，是所有生命的基础，从单细胞生物（如细菌）到复杂的多细胞生物（如人类）。这个项目解决了这个基本问题，关于黄粘球菌，一个简单的发育细菌系统。M. xanthus细胞在称为生物膜的社会群体中生长，生长的细胞聚集它们分泌的消化酶来分解环境中的复杂大分子。当营养变得有限时，黄原草通过激活一个发育程序来做出反应，从而形成一个称为子实体的多细胞结构。在这个结构中，一个细胞亚群形成具有环境抗性的黏液孢子。该项目特别侧重于确定促进黏液孢子形成的分子机制，而其他细胞要么经历自我毁灭，要么形成一种不同类型的细胞，称为外周杆细胞。这个项目测试了一个假设，即一个细胞的命运（孢子、杆状细胞或死亡）是由它在细胞分裂周期中遇到开始子实体形成的信号时走了多远决定的。实验旨在使用分子、生化和生理学方法来验证这一假设。该项目有望推进我们对细菌发育、分子信号和饥饿生理学的理解。M. xanthus是一个重要的药理学细菌家族的代表，其生产抗生素，抗肿瘤和抗真菌化合物与多细胞发育有关。该项目将继续为研究生、本科生和高中生提供实验室培训，这些学生将继续从事长期的科学事业。最后，该项目为当地一所小学提供社区服务。

Mitchell SingerDNA replication a checkpoint in regulating development in Myxococcus xanthusProposal number: 1354562Project Abstract:Understanding how individual cells interact with their environment and how that environment shapes and regulates cell growth and differentiation is fundamental to all life, from single celled organisms such as bacteria, to complex multicellular organisms such as humans. This project addresses this basic question, with respect to Myxococcus xanthus, a simple developmental bacterial system. M. xanthus cells grow in social groups called biofilms, in which the growing cells pool their secreted digestive enzymes to breakdown complex large molecules from the environment. When nutrients become limiting, M. xanthus responds by activating a developmental program that results in the construction of a multicellular structure called a fruiting body. Within this structure, a subpopulation of cells forms environmentally resistant myxospores. This project specifically focuses on determining the molecular mechanisms that promote the formation of myxospores, while other cells either undergo self-destruction or form a different type of cell called a peripheral rod cell. This project tests the hypothesis that the fate of a cell (spore, rod, or death) is determined by how far along it is in the cell division cycle when it encounters the signal to begin fruiting body formation. Experiments are designed to test this hypothesis using molecular, biochemical and physiological approaches. The project is expected to advance our understanding of bacterial development, molecular signaling, and starvation physiology. M. xanthus is a representative of a family of pharmacologically important bacteria, whose production of antibiotic, anti-tumor and anti-fungal compounds is tied to multicellular development. This project will continue to serve as laboratory training to graduate, undergraduate and high school students, who will continue with long-term careers in science. Finally this project provides community outreach to a title 1 local elementary school.