Department of Mechanical Engineering & Applied Mechanics, University of Pennsylvania, Philadelphia, Pennsylvania, USA.
Biophys J. 2010 Feb 17;98(4):617-26. doi: 10.1016/j.bpj.2009.11.010.
Undulatory locomotion, as seen in the nematode Caenorhabditis elegans, is a common swimming gait of organisms in the low Reynolds number regime, where viscous forces are dominant. Although the nematode's motility is expected to be a strong function of its material properties, measurements remain scarce. Here, the swimming behavior of C. elegans is investigated in experiments and in a simple model. Experiments reveal that nematodes swim in a periodic fashion and generate traveling waves that decay from head to tail. The model is able to capture the experiments' main features and is used to estimate the nematode's Young's modulus E and tissue viscosity eta. For wild-type C. elegans, we find E approximately 3.77 kPa and eta approximately -860 Pa.s; values of eta for live C. elegans are negative because the tissue is generating rather than dissipating energy. Results show that material properties are sensitive to changes in muscle functional properties, and are useful quantitative tools with which to more accurately describe new and existing muscle mutants.
波动型运动，如线虫秀丽隐杆线虫中所见，是在低雷诺数区域中生物体的常见游动步态，其中粘性力占主导地位。尽管线虫的运动预计是其物质性质的强函数，但测量仍然很少。在这里，对线虫的游动行为进行了实验和简单模型的研究。实验表明，线虫以周期性的方式游动，并产生从头部到尾部衰减的行波。该模型能够捕捉实验的主要特征，并用于估计线虫的杨氏模量 E 和组织粘度 η。对于野生型秀丽隐杆线虫，我们发现 E 约为 3.77 kPa，η 约为-860 Pa·s；活线虫的 η 值为负，因为组织产生而不是耗散能量。结果表明，物质性质对肌肉功能性质的变化很敏感，并且是有用的定量工具，可以更准确地描述新的和现有的肌肉突变体。
