The chemotactic response of the myxomycete Physarum polyhcepalum to amino acids, cyclic nucleotides and folic acid

The plasmodium of Physarum polycephalum exhibited positive chemotaxis towards l-alanine, l-aspartate, l-asparagine, l-glutamate, glycine, l-leucine, l-serine, and l-threonine and negative chemotaxis towards l-tryptophan. All attractant amino acids, except l-serine and l-threonine competed with each other; l-serine and l-threonine competed with the other amino acids but did not interfere with the response to each other. Cyclic nucleotides were attractants and cyclic 3′,5′- or 2′,3′-phosphate derivatives of either adenine or guanine were active, wheras compounds lacking the ring structure generally were not. Folic acid was an attractant whereas certain aromatic compounds were either inactive or repellent.