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Upcoming Condensed Matter and Biological Physics Seminars

CM

Morphogenesis of the first branchial arch - by Sevan Hopyan

Apr 28, 2017, 11:00 AM-12:00 PM

Rooms 202/204

Host: Cristina Marchetti | Contact: Tyler Engstrom, taengstr@syr.edu

The nuanced shapes of emerging organ primordia are intimately related to pattern formation and postnatal function, although the mechanisms that shape a volume of tissue in the embryo are not well understood.  The mandibular portion of the first branchial arch is composed of a volume of mesenchyme surrounded by a single cell layer epithelium.  Here we ask how this structure acquires a proximally narrow and distally bulbous shape during outgrowth.  Using the mouse embryo as a model system, we measured cell cycle times, as well as Young’s modulus and viscosity using atomic force microscopy.  Incorporating these data into a finite element model, we show that the spatial variation of cell division and physical properties is insufficient to explain mandibular arch shape.  By combining time lapse light sheet microscopy of intact mouse embryos with custom cell tracking, we observed that volumetric convergent extension due to the intercalation of mesenchymal cells in 3D likely underlies the narrow and elongate shape of the mandiublar arch mid-portion.  By knocking-in a transgenic FRET-based vinculin tension sensor into the mouse genome, we show that relatively high amplitude cortical force oscillations correlate with mesenchymal cell intercalations, and are oriented by polarised actomyosin.  Evidence from loss and gain of function studies suggest that Wnt5a acts as a directional cue to regulate both the orientation and oscillation amplitude of cell cortices.

CM

Information, Computation, and Thermodynamics in Cells - by Pankaj Mehta

May 5, 2017, 11:00 AM-12:00 PM

Rooms 202/204

Host: Lisa Manning | Contact: Tyler Engstrom, taengstr@syr.edu

Cells live in complex and dynamic environments. Adapting to changing environments often requires cells to perform complex information processing, and cells have developed elaborate signaling networks to accomplish this feat. These biochemical networks are ubiquitous in biology. They range from naturally occurring biochemical networks in bacteria and higher organisms, to sophisticated synthetic cellular circuits that rewire cells to perform complex computations in response to specific inputs. The tremendous advances in our ability to understand and manipulate cellular information processing networks raise fundamental questions about the physics of information processing in living systems. I will discuss recent work in this direction trying to understand the fundamental constraints placed by (nonequilibrium) thermodynamics on the ability of cellular circuits to process information and perform computations and discuss the implications of our results for the emerging field of synthetic biology.