| Events This Week |
Tue., February, 14th, 2:00pm |
| Meyer 6th Floor Conference Room |
| Title: How Does a Worm Wiggle?
|
| Speaker: Quan Wen |
| Locomotion requires coordinated motor activity throughout an animal’s body. Using microfluidics, optogenetics and calcium imaging, we discover that forward locomotion in C. elegans is both driven and coordinated by a novel form of proprioceptive coupling within the motor circuit. Positive bend-sensitive feedback compels each body region to bend in the same direction and shortly after the bending in the neighboring anterior region. Guided by this principle, we develop a simple computational model of worm locomotion and provide a biophysical explanation of why the speed and the shape of body undulation in C. elegans adapt to the mechanical load imposed by the environment. |
| Events Next Week |
Tue., February, 21st, 2:00pm |
| Meyer 6th Floor Conference Room |
| Title: Bacteria-driven Flows in a Thin Fluid Film |
| Speaker: Yilin Wu |
| Institution: Harvard University |
| Microbial life exists mostly as surface-associated communities called biofilms.
When establishing biofilms, many bacterial species are able to move across surfaces in
multicellular groups, a process known as swarming. Bacterial swarms provide a unique
system for the study of self-propelled particles and complex fluids. Swarms of
flagellated bacteria are covered by a thin layer of fluid. The motion of swarm fluid is
essential for the spreading and the physiology of swarms. We developed a novel method
for making micron-sized bubbles that can serve as flow tracers for thin fluid films such as
the swarm fluid. Using microbubbles, we discovered an extensive stream (or river)
flowing clockwise along the colony edge, which provides an avenue for long-range
communication between cells. We also revealed a complex pattern of fluid drifts within
the swarm, and suggested a mechanism of how cell growth and flagellar motility together
drive swarm spreading. The findings provide new insights to flagellar hydrodynamics
and surface motility, and lay down the foundation for further studies on surfaceassociated
microbial life. |