Colcemid Effects on Mitotic Synchrony and Synchronized Cells

The division and growth of mitotic cells were examined after pretreatment with colcemid. Colcemid acted on interphase cells near the mitotic period and blocked the entry of cells into metaphase. Colcemid treat-ment at 0.02 to 0.04 μg/ml for 2 hours was adequate for obtaining undeterio-rated synchronous cell growth. During this treatment mitotic collections in-creased approximately 40% compared to the untreated control culture. The purity of the harvested cells was more than 85 %. The median generation time did not differ significantly between reversed cells and untreated cells. How-ever, colcemid-treatment resulted in delaying the increase of DNA by about 2 hours during synchronous growth. A similar delay was found in the cyclic change of X-ray survival during the DNA synthetic period.