STXM X-ray absorption images recorded to map the distribution of DNA and protein on chromosomes. (A) Pre-edge at 280.0 eV. (B) DNA absorption at 287.4 eV. (C) Protein absorption at 288.2 eV. (D) Distribution of DNA (B - A). (E) Distribution of protein [C - (B + A)]. (F) Composite image showing distribution of DNA and protein. All scale bars are in optical density.
Yangquanwei et al. Nanoscale Research Letters 2013 8:463 doi:10.1186/1556-276X-8-463