COLLABORATIVE RESEARCH: Muscle fiber size as a determinant of metabolic design

大多数细胞很小，沿最短轴尺寸为100mm。小的尺寸促进了高的表面积体积比和短的细胞内扩散距离，这两者都被认为是细胞的必要设计特征。然而，有些生物的细胞比正常细胞大近10倍。在一些甲壳类动物中，幼年动物的肌肉纤维具有“正常”尺寸（100毫米），但随着动物的生长，其中一些纤维可能超过600毫米。在保持功能的同时获得如此大的大小应该是困难或不可能的，这就提出了一个问题：控制单元格大小的规则和权衡是什么？发育中细胞大小增加的影响将在分离的蓝蟹（Callinectes sapidus）的快速收缩肌纤维中进行检验。肌肉结构、新陈代谢和收缩的大小相关变化将使用包括电子显微镜、化学分析、核磁共振和极谱耗氧量测量在内的方法进行检查。此外，将生成一个反应扩散数学模型，以帮助解释实验数据。这项研究构成了一种广泛适用的细胞能量学的新观点。一旦建立了极端模型系统的规则，该方法就可以应用于传统模型。这对于研究能量挑战的影响特别有用，比如缺氧、锻炼制度和发育过程，所有这些都与细胞大小有内在的联系。这是生物学家和化学工程师的合作。牵头机构（UNCW）强调本科教育，本科生将与研究生和pi一起工作。牵头机构的研究环境将因该项目的多学科方法而得到改善，学生将受益于合作机构的设施和专业知识。在合作院校（FSU），这项工作还将涉及本科生和研究生的培训。数学建模将构成至少一名研究生论文的基础，并且将寻求本科生参与项目的所有阶段。

Most cells are small, with dimensions 100mm along the shortest axis. Small size promotes a high surface area to volume ratio and short intracellular diffusion distances, both of which are thought to be necessary design features of cells. However, cells of some organisms are nearly 10-fold larger than the norm. In some crustaceans, muscle fibers from juvenile animals have "normal" dimensions (100mm), but as the animals grow, some of these fibers may exceed 600mm. Attaining such a large size while maintaining function should be difficult or impossible, which raises the question: What are the rules and tradeoffs that govern cell size? The effects of developmental increases in cell size will be examined in isolated fast-twitch muscle fibers of the blue crab, Callinectes sapidus. Size-associated changes in muscle structure, metabolism, and contraction will be examined using methods that include electron microscopy, chemical assays, nuclear magnetic resonance and polarographic measurements of oxygen consumption. In addition, a reaction-diffusion mathematical model will be generated to aid interpretation of experimental data. This study constitutes a novel view of cellular energetics that is broadly applicable. Once the rules are established for an extreme model system, the approach can be applied to traditional models. This will be particularly useful for studying the impact of energetic challenges like hypoxia, exercise regimes and developmental processes, all of which are inherently linked to cell size. This is a collaboration of biologists and chemical engineers. The lead institution (UNCW) emphasizes undergraduate education, and undergraduate students will work alongside graduate students and the PIs. The research environment at the lead institution will be enhanced by the project's multi-disciplinary approach, and students will benefit from facilities and expertise at the collaborating institution. At the collaborating institution (FSU), the work will also involve training of undergraduate and graduate students. Mathematical modeling will form the basis for the dissertation of at least one graduate student, and undergraduate participation will be sought for all phases of the project.