[Phys-seminars] 2018-05-10 Lasers Seminar

okrichev okrichev at bgu.ac.il
Thu May 10 10:22:20 IDT 2018

Lasers Seminar

 DATE: 10-05-18

 TIME: 15:30

 PLACE: Physics building (#54) room 207

Super-Resolution Imaging and Structure Measurements of Chromatin and of Supercoiled DNA Plasmids

E. Benjamin, I. Michaelovich, Physics Department, Ben-Gurion University

The organisation of the nucleic material in eukaryotic cells, the chromatin, affects many cellularprocesses. Though chromatin has been subject of research for almost 150 years, its exact structure in the sub-chromosome scale is still unknown. We present a study of chromatin structure inside the nucleus using a combination of scanning fluorescent correlation spectroscopy (sFCS) and super-resolution time- gated stimulated emission depletion microscopy (gSTED). Our preliminary results shows evidence of Gaussian shaped sub-structures on the scale of 300-400 nm, a behaviour typical of a "beads-on-a-spring" system. Furthermore we used the combined sFCS-gSTED approach to measure the structure of superhelical DNA in solution. We compare the experimental measurements to theoretical models and computer simulations, that take into account DNA twist and bending rigidity, electrostatic interactions and DNA configurational entropy.

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