AMINO ACID CHEMORECEPTION BY PLANARIAN DUGESIA DOROTOCEPHALA

1. 1. Dugesia dorotocephala shows a positive chemotaxis to the amino acids lysine and glutamine with a threshold concentration of about 5 × 10-6 M. 2. 2. This response is not elicited by the structurally similar amino acids aspartic acid, asparagine, α-ketoglutaric acid, δ-hydroxylysine or glutamic acid; the first three named elicit negative responses. 3. 3. Several other amino acids gave positive responses only when presented in much higher concentrations, while another group possessed no discernible stimulatory properties. © 1969.