NSF Postdoctoral Fellowship in Biology: From helical fibers to vortical flow: unravelling the contributions of muscle geometry and physiology to swimming performance

这一行动资助了NSF 2022财年生物学博士后研究奖学金，扩大了生物学中代表性不足的群体的参与。该研究金支持一项针对该研究员的研究和培训计划，该计划将增加生物学中代表性不足的群体的参与。这位研究员的研究目标是了解肌肉解剖上的微小差异是如何影响动物的运动的。这个研究项目从一个简单的观察开始：侧弯是脊椎动物最古老和最常见的运动形式。几乎所有的鱼都是通过前后弯曲身体游泳的。事实上，对于大多数脊椎动物来说，移动就是弯曲。然而，使用身体弯曲的动物受到生物力学的约束：当肌肉弯曲脊椎时，肌肉组织变形不均匀。靠近脊椎的肌肉只会变短一点，而远离脊柱的肌肉会变短很多，这两种情况都不是最佳的。这种不均匀的肌肉变形有破坏运动能力的风险。这项研究试图确定身体弯曲的脊椎动物是否进化出了专门的肌肉纤维几何形状来解决这个生物力学问题。为了回答这些问题，这位研究员将使用多种尖端方法来分析和模拟鱼在水中的运动。为了增加对STEM的参与，该研究员将在奇卡诺人和美洲原住民促进会(SACNAS)担任领导职务。为了确定脊椎动物是如何解决弯曲的生物力学问题的，这位研究员正在进行两项研究，检查鱼类及其几何复杂的轴向肌肉结构。这项工作将涉及多种方法，包括3D建模、体外肌肉生理学和粒子成像测速仪(PIV)来测量水流模式。第一项研究测量了在不同速度下游泳时的体曲率、肌肉活动和体液流量。第二项研究使用一种名为“工作环”的经典技术来测量具有不同纤维几何形状的肌肉纤维束的收缩性能，通过使用3D数学模型和肌肉纤维角度的3D测量来计算。这些实验的数据将被组合在一起，生成内部肌力和外部水动力的空间量化地图。这些结果将决定鱼肌肉复杂的螺旋纤维几何形状是否解决了弯曲问题。这项研究还将扩大对肌肉中产生的力是如何传递到水中的理解，以及鱼在不同游泳速度下是否会改变策略。为了长期的职业发展，这位研究员正在接受学生指导和实验室管理方面的培训。为了扩大代表不足的少数群体的参与，该研究员将参加SACNAS提供的领导力课程，并将参加波士顿科学博物馆的外展活动。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

This action funds an NSF Postdoctoral Research Fellowship in Biology for FY 2022, Broadening Participation of Groups Underrepresented in Biology. The Fellowship supports a research and training plan for the Fellow that will increase the participation of groups underrepresented in biology. The goal of the Fellow’s research is to understand how animal movement is affected by small differences in muscle anatomy. This research project begins with a simple observation: bending from side to side is the oldest and most common form of vertebrate locomotion. Nearly all fishes swim by bending their bodies back and forth. For most vertebrates, in fact, to move is to bend. However, animals that use body bending are subject to a biomechanical constraint: as muscles flex the spine, muscle tissue deforms unevenly. Muscle close to the spine only shortens a little, and muscle far from the spine shortens a lot, and neither of these are optimal. This uneven muscle deformation risks sabotaging locomotor performance. This research seeks to determine whether body-bending vertebrates may have evolved specialized muscle fiber geometries to solve this biomechanical problem. To answer these questions, the Fellow will use multiple cutting-edge approaches to analyze and model fish motion in water. To increase participation in STEM, the Fellow will serve in leadership roles in the Society for the Advancement of Chicanos and Native Americans (SACNAS). To determine how vertebrates have solved the biomechanical problem of bending, the Fellow is conducting two studies examining fish and their geometrically complex axial musculature. The work will involve multiple approaches including 3D modelling, in vitro muscle physiology, and particle imaging velocimetry (PIV) to measure patterns of water flow. The first study measures body curvature, muscle activity, and fluid flow in largemouth bass swimming at different speeds. The second study uses a classic technique called a “work loop” to measure contractile performance for muscle fiber bundles with different fiber geometries, as calculated using a 3D mathematical model and 3D measurements of muscle fiber angle. The data from these experiments will be combined to generate a spatial quantitative map of internal muscular forces and external hydrodynamic forces. These results will determine if the complex helical fiber geometry of fish muscles solves the bending problem. This research will also expand the understanding of how force generated within muscles is transmitted into the water, and whether fish shift strategies at different swimming speeds. For long-term career development, the Fellow is being trained in student mentorship and lab management. To broaden participation of underrepresented minorities, the Fellow will participate in leadership programs offered by SACNAS and will also participate in outreach at the Museum of Science in Boston.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.