Demonstration of Axial Elements of Sex Vesicles of Spermatocytes Using Coomassie Brilliant Blue

The axial element of sex chromosomes in the sex vesicle of rat and mouse spermatocytes has been visualized under the light microscope by the dye Coomassie brilliant blue (CBB). After staining in the CBB solution for 3-10 minutes, the axial elements appeared as darkly stained threads in the sex vesicles, whereas in controls stained with Giemsa or carbol fuchsin, the sex vesicles were usually uniformly stained. The axial elements are best seen when chromosome preparations were made by the flame drying technique. In rat spermatocytes the staining quality could be further improved by a brief treatment with trypsin solution (0.025%).

The CBB staining procedure is simple and easily controllable. The results suggest that the CBB stained material is protein in nature and is more resistant to trypsin digestion than other nuclear proteins.