Hematin--requiring plasmodial myxomycete.

Daniel, John W. (University of Wisconsin, Madison), Jacqueline Kelley, and Harold P. Rusch. Hematin-requiring plasmodial myxomycete. J. Bacteriol. 84:1104-1110. 1962.-The myxomycete Physarum polycephalum, previously shown to require chick embryo extract for growth on a partially defined, soluble medium, grows as well if hematin or certain hemoproteins are substituted for the embryo extract. Hematin is also required as a growth factor if the organism is grown on a synthetic medium. Of the variety of porphyrins tested only iron protoporphyrin IX is utilized for growth by P. polycephalum. Protoporphyrin IX is inactive. Protein-bound iron porphyrin is active at one-tenth the concentration of free hematin. Although hematin completely replaces embryo extract, the extract activity has properties not characteristic of hematin or the hemoproteins tested: ladility to light and rapid plasmodial uptake.