Simultaneous collection of topographic and fluorescent images of barley chromosomes by scanning near-field optical/atomic force microscopy

The present study investigated the applicability of scanning near-field optical/atomic force microscopy (SNOM/AFM) to observations of YOYO-1 stained barley chromosomes. Using this technique, topographic and fluorescent images in the same portion were obtained simultaneously, thus enabling the precise analysis of fluorescent structures in relation to the morphology of chromosomes. In YOYO-1 stained chromosomes, the fluorescent intensity roughly reflected the local amount and/or density of DNA in chromosomes. R-banding of chromosomes stained with YOYO-1 and methyl green was also observed clearly as bright spots of various sizes by this microscope. Thus, the SNOM/AFM is expected to become a useful tool for analysing the structure and function of chromosomes more precisely than before.