Education

• 2019- now, PhD Optical Super-Resolution Measurement of DNA Structure: from Superhelical Plasmids to Chromatin
  with Oleg Krichevsky
• 2018- 2019, MSc Super-Resolution Scanning Fluorescence Correlation Spectroscopy Measurements of Supercoiled Plasmid Structure
  with Oleg Krichevsky

  Abstract/Description: The structure of circular DNA (plasmids) is determined by its superhelicity, a topological
  quality which can be thought of as the excess, or defficiency, of whole twist turns of the double
  helix around its axis. Since supercoiled plasmids are a few hundred nanometers in size, their
  structural details cannot be observed optically. While there have been studies to characterize
  the structure of supercoiled plasmids, none have attempted to probe the structure in a liquid
  solution, resembling physiological conditions.
  We present an in-vitro study of the structure of supercoiled plasmids in solution: Plasmids
  are labeled uniformly and covalently with minimal structural interference. A combination
  of scanning
  Fuorescent correlation spectroscopy (sFCS) and time-gated stimulated emission
  depletion microscopy (gSTED) are utilized to measure the static structure factor of plasmid
  topoisomers, and its dependence on superhelicity. By analyzing the results and comparing
  with a DNA simulation, we shed more light on the actual structure of supercoiled plasmids
  - support for a branched plectonemic structure is given, and a qualitative resemblance is
  observed between the measured and simulated gyration radii and structure factors of both
  relaxed and supercoiled plasmids.