dl-Methionine in Developmental Growth. ∗

Abstract

It is known that methionine can replace cystine as a growth essential in the diet of rodents. 1 , 2 , 3 This report extends to the invertebrate marine hydroid Obelia geniculata the premise that this sulfur-containing amino acid is a growth stimulant. The purpose is to see whether lower as well as higher organisms can utilize — S — sulfur for growth purposes, and whether any particular phase of growth activity is responsive thereto, since this point is unsettled in work with rodents.

Through the courtesy of Professor du Vigneaud we obtained enough dl-methionine for 32 experiments. In these the developmental growth of some 6000 animals in methionine cultures was compared with that of a like number in plain sea water. Description of the organism and its growth together with that of the experimental and other procedures is given in detail elsewhere. 4 , 5 Tests and controls were run simultaneously under like conditions of temperature, illumination, and pH. Results are tabulated as condensed consistency data from which is seen the trend of test deviation from control in expression of new growth initiation, proliferation, differentiation, and organization, as well as that for maintenance, regression, and catabolism. 6 The table also gives the concentrations used and the number of experiments, colonies, hydranths, and gonophores. Since general reaction was essentially the same in the stated concentrations the data were combined into one set of figures to save space. Those for the 6 experiments at M/50,000 and M/25,000 were omitted because they show nothing but toxicity.