Isolation, Electron Microscopy, and Computer Processing of Chromosomes

Abstract

Computer processing of electron microscope images has been of great value in the delineation and correlation of structural characteristics. An appropriate system for such study is that which enhances the high spatial frequency components in an image, thereby assisting in the observation of its fine structure. The present study reports on the isolation of intact chromosomes from a mammalian cell culture and their examination in the transmission electron microscope. The images of the chromosomes were then enhanced by computer processing.Isolation of the chromosomes and their examination in the electron microscope was done in the Dept, of Biology of the Massachusetts Institute of Technology. A mammalian cell line, STR-T, was maintained under standard conditions. Fresh cultures were prepared and when the cells were in log phase, colchicine was added to arrest the chromosomes at metaphase. After chemical fixation with ethanol-acetic acid (3:1), the cells were mechanically dislodged by scraping the vessel surface with a rubber policeman. The cells were place in a test tube and gently homogenized by hand.