Effect of collagen and acid polysaccharides on the growth of BHK-21 cells in semi-solid media.

Abstract

PLATING of individual cells in semi-solid media based on bacteriological agar is a common means of assaying the “transforming” activity of potential cancer-inducing agents1. Transformation is associated with an increased ability to form three dimensional colonies in agar: it often results from the treatment of mammalian cells with viruses2,3 or chemical carcinogens4. With other cells, large numbers have to be plated before even a few colonies appear. Moreover, many of the colony-forming cells turn out to be “mutants” or “spontaneous” transformants, not capable of indefinite propagation in agar medium5. Although the actual frequency with which such colonies appear may vary greatly (in the range 10−6 to 10−4), it is generally true that transformation results in much greater colony-forming ability relative to the parental cells.