Mechanics and Mechanosensation in Adaptive Locomotor Systems

Natural environments are heterogeneous and can fluctuate with time. As such, biomechanical systems from proteins to whole organisms have developed strategies to sense and deal with considerable spatial and temporal variability. I will discuss two (quite different!) broadly successful locomotive modes: flagellated motility in bacteria and walking in panarthropods. (1) A bacterium's life can be complicated: it must swim through fluids of varying viscosity as well as interact with surfaces and other bacteria. We characterize the mechanosensitive adaptation in bacterial flagella that facilitates these transitions by using magnetic tweezers to manipulate external torque on the bacterial flagellar motor. Our model for the dynamics of load-dependent assembly in the flagellar motor illustrates how this nanomachine allows bacteria to adapt to changes in their surroundings. (2) Panarthropods are a diverse clade containing insects, crustaceans, myriapods and tardigrades. We show that inter-limb coordination patterns in freely-behaving tardigrades replicate several key features of walking in insects across a range of speeds and substrates. In light of these functional similarities, we propose a simple universal locomotor circuit capable of robust multi-legged control across body sizes, skeletal structures, and habitats.

Jasmine Nirody is an Independent Fellow at the Center for Studies in Physics and Biology at The Rockefeller University and at All Souls College, University of Oxford. Her postdoctoral work was partially funded by a Fellowship in Complex Systems from the James S. McDonnell Foundation. Previously, she received her PhD in Biophysics from the University of California, Berkeley, where she was advised by George Oster. At Berkeley, she was a Fellow at the Center for Integrative Biomechanics in Education and Research (CiBER). Her thesis won the 2018 Award for Outstanding Dissertation Work in Biological Physics from the American Physical Society. She is a biomechanist and integrative biologist; she studies the physical interactions between organisms and their environments, and how these interactions in turn shape organismal form and behavior.