English: Super-resolution single molecule localisation microscopy using DNA structure fluctuation assisted binding activated localisation microscopy (fBALM). Left – conventional diffraction limited image of the DNA in a HeLa cell labelled with a fluorescent DNA-binding dye. Major nuclear structures just as nucleoli are clearly visible. Note a poor contrast. Right – fBALM super-resolution image of the same HeLa nucleus. The image has been reconstructed from more than 2x106 single molecule signals acquired from the nucleus undergoing stochastic changes to DNA structure due to the specific chemical environment provided. The local DNA structure instability disables fluorescence in the vast majority of the cases whereas the stochastic local DNA stability enables transient fluorescence emission from a single DNA binding site. This methodology yields a structural resolution in the range of 50 nm.

For more details see reference: Imaging chromatin nanostructure with binding-activated localization microscopy based on DNA structure fluctuations  Aleksander Szczurek, Ludger Klewes, Jun Xing, Amine Gourram, Udo Birk, Hans Knecht, Jurek W. Dobrucki, Sabine Mai, Christoph Cremer. Nucl Acids Res (2017) Published: 13 January 2017 DOI: https://doi.org/10.1093/nar/gkw1301

Square inset demonstrates an enlarged image of a nucleolus. Scale bar corresponds to 500 nm.