THE EFFECT OF COLAMINE ON GROWTH AND PROTOPLASMIC STREAMING IN AVEN

Abstract

AS FAR as is known, there is no substance in animals comparable to the auxins which control the growth of plants. Extracts of animal tissues, however, contain substances which inhibit the growth of animal cells in tissue culture. Among these inhibiting substances is colamine, or ethanol-2-amine. The history of the study of inhibitors extracted from liver is surveyed by Medawar (1937). In brief, liver extracts have been known for some time to have an inhibitory effect on cells in tissue culture. In 1926, Heaton made the first exhaustive studies of this factor in aqueous or dilute alcoholic extracts of adult liver. The extracts inhibited the growth of chick heart fibroblasts but had no effect on a number of different epithelial tissues. Heaton also extracted a similar factor from brewer's yeast, but the inhibition was probably due-to malt present in the yeast extracts, since Heaton himself later showed that extracts of malt contained active inhibitors of this kind. Substances inhibiting the growth of mesenchvme but not epithelium have been extracted frorn germinated and ungerminated barley, from the seeds of maize, wheat, and oats, from whole grain flour and even whole grain bread. The inhibitor has also been obtained in large quantities from whole orauges. All the extracts contained yellow pigments in varying amounts, but removal of the pigment did not affect the activity of the inhibitor. Brues and co-workers (1936) have recently studied the effect of these growth inhibiting factors on animal tissue cultures. They used saline or alcoholic extracts of liver to treat different embryonic and sarcomatous tissues. The radius of growth of cultures of fibroblasts was greatly diminished and there was a decrease in the wandering monocytes, although the life span of the treated cultures was not affected and rare mitoses could be found. Cells were smaller in treated than in untreated material. Epithelium was not affected. Brues et al. (1940) later identified colamine in the inhibitory extract. Colamine produced inhibition of growth in concentrations of 0.25 to 2 mg. per cc. A number of other amines were also active. The following study was undertaken to determine whether colamine has any effect on growth in plants comparable to its action on animal tissues, and to study the effect of colamine on protoplasmic streaming in plants, more especially to study its effect in the presence of auxin.