The Cytoarchitecture of Large Bacteria

智力优势：以原始人为模型，Angert实验室的长期研究目标之一是解决所有大细胞面临的一个基本问题；一个表面体积比小的细胞如何克服生物活性分子扩散系数对其施加的限制？Epulopiscium spp.的雪茄状细胞达到600 μ m x 80 μ m，是迄今为止所描述的最大的异养细菌。尽管体型庞大，原始人却能维持高水平的活动。位于细胞质外围的大量重复DNA的存在和高度内陷的细胞膜可能是在拟古猿中维持大细胞大小的重要适应。基因组资源的扩增和分布有助于支持强大的代谢，而细胞膜和膜相关转运蛋白的扩张可以增强与环境的交换，促进细胞质内分子的运动。在这个项目中，Angert博士和她的同事们试图进一步表征这些特征，并确定1)细胞中DNA复制的时间和位置，2)不同命运的多条染色体如何定位和管理，以及3)细胞膜对分子扩散的影响。计划继续努力培育拟古猿。在宿主外维持拟古猿将允许进行体内实验，并最终开发遗传工具。更广泛的影响：这些项目为对科学感兴趣的研究生、本科生和高中生提供了重要的教育和培训机会。所有学生都将获得基本分子生物学、微生物学和显微技术的经验。根据项目的不同，学生将在基因组学、显微镜学、系统发育分析或纳米生物技术等领域获得更广泛的经验。这样的实验室研究经验对青年科学家的发展是必不可少的。拟古猿为传达细菌细胞的基本概念提供了一个令人兴奋的模型。这些细胞在视觉上很吸引人，可以用肉眼看到。事实上，Epulopiscium spp.如此之大，但不致病，使它们成为微生物世界的一个很好的代表，不仅对生物学学生，而且对公众也是如此。为了方便信息流通，我们建立了一个以猿类为特色的网站。各级学生都参与了网站的开发和维护。这个项目向学生灌输了所有研究人员向公众传播信息的责任，它将增强学生向不同受众传达他们的工作及其意义的能力。此外，安杰特实验室的成员还协助康奈尔大学生物教师学院举办了一个名为“微生物世界”的暑期讲习班。

Intellectual Merit: Using Epulopiscium as a model, one of the Angert lab's long term research goals is to address a fundamental problem faced by all large cells; how does a cell with a small surface-to-volume ratio overcome constraints imposed on it by the diffusion coefficients of bioactive molecules? With cigar-shaped cells reaching 600 µm x 80 µm, Epulopiscium spp. are the largest heterotrophic bacteria described to date. Despite its size, Epulopiscium is able to support a high level of activity. The presence of large amounts of repetitive DNA located at the periphery of the cytoplasm and a highly invaginated cell membrane may be significant adaptations to maintain large cell size in Epulopiscium. The amplification and distribution of genomic resources help support a robust metabolism while expansion of the cell membrane and membrane associate transporters may enhance exchange with the environment and facilitate movement of molecules within the cytoplasm. In this project Dr. Angert and her colleagues seek to further characterize these features and determine 1) the timing and location of DNA replication in the cell, 2) how multiple chromosomes with differing fates are positioned and managed and 3) the impact of intracellular membranes on molecular diffusion. Continued efforts toward culturing Epulopiscium spp. are planned. Maintaining Epulopiscium outside of its host will allow for in vivo experiments and ultimately the development of genetic tools. Broader Impacts: These projects provide significant educational and training opportunities for graduate, undergraduate and high school students interested in the sciences. All students will gain experience in basic molecular biology, microbiology and microscopic techniques. Depending on the project, students will gain more extensive experience in areas such as genomics, microscopy, phylogenetic analyses or nanobiotechnology, to name a few. Such laboratory research experience is essential to the development of a young scientist. Epulopiscium provides an exciting model for conveying basic concepts of the bacterial cell. These cells are visually appealing and can be seen with the unaided eye. The fact that Epulopiscium spp. are so large, but not pathogenic, makes them a good representative of the microbial world not only for biology students but for the general public as well. To facilitate information flow, a website featuring Epulopiscium has been established. Students at all levels are involved in the development and maintenance of the site. This project instills in students the responsibility of all researchers to disseminate information to the public and it will enhance the ability of the students to communicate their work and its significance to a diverse audience. In addition, members of the Angert Lab assist with a Cornell Institute for Biology Teachers Summer Workshop called The Microbial World.