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Physics Colloquia 293 (10/5/18)

October 5, 2018 - 10:30am

Ryan McGorty, University of Californa, Davis

Abstract:

The transport of large biomacromolecules, like DNA, is strongly influenced by how crowded the cellular environment is. Crowding not only hinders transport but also may compact, elongate or in other ways vary the conformation of large macromolecules. To better understand the effects of crowding within cells, we look at DNA diffusing within well-characterized in vitro networks of actin filaments and microtubules. Building a complete picture of how large DNA molecules move through such environments requires that we observe the conformational dynamics of single-molecules andthat we observe ensemble dynamics over length scales large compared to the network mesh size. In this talk, I will describe a recently developed platform allowing for such measurements. We use single-molecule imaging and tracking to observe the conformational changes of DNA in varied environments. Complementing such data are measurements using light-sheet microscopy and dynamic differential microscopythat provide ensemble dynamics—similar to data dynamic light scattering can provide—over much larger length and timescales. Much of this talk will be devoted tohow differential dynamic microscopy can be used and our recent extensions of that method. After discussing how differential dynamic microscopy has been used to investigate DNA dynamics, I will discuss how we are using similar microscopy methods to study capillary waves in colloidal fluids. 

Flyer File: mcgorty_ryan_physics_flyer.pdf