Crystalloids of Phycomyces Sporangiophores: Nature and Photosensitive Accumulation

Crystalloids accumulate in the vacuoles of the giant sporangiophores of Phycomyces blakesleeanus Burgeff during growth. On the basis of solubility in alkaline solutions, cytochemical staining reactions, trypsin sensitivity, optical absorption and response in the Lowry protein test, the crystalloids have been judged to consist principally of an acidic protein. In assays by Lowry test and by reference to optical absorption at 280 mmu, dark-grown sporangiophores were consistently found to contain from 2 to 4 times as much crystalloid material as light-grown counterparts. Concurrent assays of soluble phenolic materials revealed no significant effect of culture illumination, while carotene content of sporangiophores and mycelium was found to be raised from 2 to 4-fold by illumination during growth.