Biophysics Seminar

All future

Thursday, October 25th 2018
10:10 am:
Biophysics Seminar in 120 PAN
Speaker: Oleg Krichevsky, Molecular Biophysics Lab, Ben-Gurion University
Subject:  T cell communication through cytokines follows a simple sink-diffusion model

Immune cells communicate by exchanging cytokines to achieve a context-appropriate response, but the distances over which such communication happens are not known. We used theoretical considerations and experimental models of immune responses in vitro and in vivo to quantify the spatial extent of cytokine communications in dense tissues. Using T cell exchange of IL-2 as a model system, we established that competition between cytokine diffusion and consumption generated spatial niches of high cytokine concentrations with sharp boundaries. The size of these self-assembled niches scaled with the density of cytokine-consuming cells, a parameter that gets tuned during immune responses. In vivo, we measured interactions on length scales of 80–120 um, which resulted in a high degree of cell-to-cell variance in cytokine exposure. Despite the complexity of the immune organs, the profiles of cytokine fields both in vitro and in vivo quantitatively follow the predictions of a simple model, essentially without any free parameters.

Ref. Oyler-Yaniv A, Oyler-Yaniv J, Whitlock B.M, Liu Z, Germain R.N, Huse M, Altan-Bonnet G. and O. Krichevsky (2017) , Immunity, 46, 609-620.

Faculty Host: Elias Puchner

Thursday, November 1st 2018
10:10 am:
Biophysics Seminar in 120 PAN
Speaker: Douglas G. Mashek, Professor, Department of Biochemistry, Molecular Biology and Biophysics and Department of Medicine, Division of Diabetes, Endocrinology and Metabolism, University of Minnesota
Subject: The fascinating world of lipid droplet biology

Lipid droplets are recognized to be the primary storage form of energy in most cell types. While this important function is critical to supply cells or organisms with energy during times of nutrient deprivation, their role beyond energy storage has largely been unexplored. Our laboratory has focused on elucidating the mechanisms through which lipid droplets communicate within cells to coordinate energy storage with cell signaling and metabolism. Our work on hepatic lipid droplets has identified important functions for these dynamic organelles in regulating lipid and glucose metabolism, hormone signaling and cell proliferation. Specifically, data will be presented showing that lipid droplet catabolism promotes signaling networks to control mitochondrial biogenesis and function. Moreover, recent insights into the mechanisms through which lipid droplets are catabolized via autophagic pathways will also be discussed. In summary, this presentation will highlight novel roles for lipid droplets and their metabolism in cellular and organismal biology and their importance in human health.

Thursday, November 8th 2018
10:10 am:
Biophysics Seminar in 120 PAN
Speaker: Isaac Angert, graduate student in Jochen Mueller’s lab, School of Physics and Astronomy, University of Minnesota

Thursday, November 15th 2018
10:10 am:
Biophysics Seminar in PAN 120
Speaker: John Marko, Northwestern University
Subject: Single-molecule studies of protein-DNA interactions

All processing of DNA - transcription, replication, recombination and
repair - depend on the interactions of proteins with DNA. I will discuss
single-molecule methods for analyzing protein-DNA interactions, starting
with the (statistical)-mechanical response of DNA molecules and how
monitoring that can allow novel quantitative studies of proteins that fold
and change topology of DNA molecules. I will then describe a phenomenon
that appears pervasive for biomolecule interactions - "facilitated
dissociation" - that makes rates of turnover of molecular complexes in vivo
very different from what we observe in vitro.

Thursday, November 29th 2018
10:10 am:
Biophysics Seminar in 120 PAN
Speaker: Santosh Adhikari, graduate student in Elias Puchner's lab, School of Physics and Astronomy, University of Minnesota

Thursday, December 6th 2018
10:10 am:
Biophysics Seminar in 120 PAN
Speaker: Steven Vogel, NIH/NIAAA

Thursday, April 4th 2019
10:10 am:
Biophysics Seminar in 120 PAN
Speaker: Sara Walker, Assistant Professor, School of Earth and Space Exploration, ASU

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