γ-Carotene in the sexual phase of the aquatic fungus Allomyces

Abstract

It has long been noted that, among the majority of plants and animals, relatively concentrated stores of carotenoids are to be found in certain particular tissues, structures and secretions associated with reproduction. Many of the yellow, orange or red pigments of pollen, stamens, stigmata, petals, seeds, and fleshy parts of fruits of higher plants are outstanding examples. Likewise, among animals, considerable attention has been given to the striking manifestation of similar pigments in the eggs of countless species of invertebrates and fishes, as well as in those of birds and some amphibians and reptiles, and in the corpora lutea and milk-fat of certain mammals. Investigations of such compounds (even apart from the A vitamins and their common precursors) in reproductive structures and their accessories have suggested to many the possibility that these pigments play definite biochemical roles in processes associated with sexual maturation, fertilization, and embryonic development. Although the carotenoids are not as universally distributed among the fungi as they are in other cryptogams, pigments of this type have been identified in a wide variety of Basidiomycetes and Ascomycetes, as well as in some genera of Myxomycetes and Phycomycetes. As far as we are aware, however, the concentration of carotenoids in the sexual reproductive structures of fungi is comparatively rare. Of particular interest in this connexion are the studies of pigments in the Mucorales. Lendner (1918), and Satina and Blakeslee (1926 a ) remarked upon the occurrence of a yellow substance, concentrated particularly in the progametes and gametes of many Mucors. In 1927 Chodat and Schopfer, after extracting and testing the pigment form Mucor hiemalis , identified it as a carotene. Their data suggest that α-carotene may have been the preponderant pigment, mixed, perhaps, with the β -isomer.