David, Charles N.; Easterbrook, Kenneth (1971): FERRITIN IN THE FUNGUS PHYCOMYCES. In: Journal of Cell Biology, Vol. 48: S. 15-28




The iron-protein ferritin has been purified from mycelium, sporangiophores, and spores of the fungus Phycomyces blakesleeanus. It has a protein-to-iron ratio of 5, a sedimentation coefficient of 55S, a buoyant density in CsCI of 1 .82 g/cm3, and the characteristic morphology of ferritin in the electron microscope . Apoferritin prepared from Phycomyces ferritin has a sedimentation coefficient of 18S and consists of subunits of molecular weight 25,000 . In the cytoplasm of Phycomyces, ferritin is located on the surface of lipid droplets (0 .5-2 .0 y in diameter) where it forms crystalline monolayers which are conspicuous in electron micrographs of sporangiophore thin-sections . Ferritin is found in all developmental stages of Phycomyces but is concentrated in spores . The level of ferritin iron is regulated by the iron level in the growth medium, a 50-fold increase occurring on iron-supplemented medium .