Biophysical Society Bulletin | October 2021

Publications

Know the Editor Helmut Schiessel

Technische Universität Dresden

Editor, Genome Biophysics Biophysical Journal

Helmut Schiessel

What are you currently working on that excites you? This year, I joined the newly founded Cluster of Excellence Physics of Life in Dresden. This new environment inspired some new ideas about how cells manage to duplicate them- selves. This is trivial for DNA, but what about the epigenetic state? For instance, half of the various post-translational modifications on the nucleosomes are lost during cell division. I am trying to understand the mechanism that restores the original state, which involves polymer physics and protein droplets. My hope is that epigenetics is often based on simple physics. It’s exciting to be at the early stages of a project when you can just get a first glimpse of where it’s going. At a cocktail party of non-scientists, how would you explain what you do? I am obsessed with all sorts of information written along the DNA, but not to the extent that I monologue people at a cock- tail party! If asked, I would compare biological cells with radio receivers. The latter selects a single radio program from the multiplexed radio waves. Similarly, a cell “listens” to what is written on its DNA. By turning the receiver’s dial, you can turn on different programs while the cell uses different machines to read the different layers of information. One layer contains the genes, another mechanical information that controls the DNA’s own packaging, and another the speed of protein production, which affects the quality of the product. I’m trying to show that all of this information can be written along the same stretch of DNA, and that this actually happens on real genomes.

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Figure 1

BJ Editor’s Pick Light scattering in TIRF microscopy: A theoretical study of the limits to surface selectivity Jeremy J. Axelrod, Daniel Axelrod “Techniques that employ illumination of a microscopic sample by an evanescent field (most commonly by total internal reflection fluorescence) are surface selective because the evanescent field layer ideally is very thin. However, refractive index inhomogeneities in the sample can scatter some of the illumination, increase its effective thickness, and thereby decrement the surface selectivity. From a theoretical optics viewpoint, this work examines how significant this problem might be on typical samples, such as living cell cultures.”

Version of Record Published June 29, 2021 DOI:https:/doi.org/10.1016/j.bpj.2021.06.025

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