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

大多数单元格都很小，最短的轴线尺寸为100 mm。小尺寸有利于提高电池的表面积体积比和细胞内扩散距离，这两者都被认为是电池的必要设计特征。然而，一些生物体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)，但随着动物的成长，其中一些纤维可能会超过600毫米。在保持功能的同时获得如此大的尺寸应该是困难的或不可能的，这就提出了一个问题：管理单元大小的规则和权衡是什么？细胞大小的发育增加的影响将在蓝蟹的分离快速抽动肌肉纤维中进行检验。肌肉结构、新陈代谢和收缩与大小相关的变化将使用包括电子显微镜、化学分析、核磁共振和氧气消耗极谱测量在内的方法来检查。此外，还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。一旦为极端模型系统建立了规则，该方法就可以应用于传统模型。这将特别有助于研究能量挑战的影响，如低氧、运动制度和发育过程，所有这些都与细胞大小固有地联系在一起。这是生物学家和化学工程师的合作成果。牵头机构(UNW)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通过该项目的多学科方法得到改善，学生将受益于合作机构的设施和专业知识。在合作机构(FSU)，这项工作还将涉及本科生和研究生的培训。数学建模将成为至少一名研究生论文的基础，并将在项目的所有阶段寻求本科生的参与。

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.