| During past years, slime molds and other lower eukaryotes have been used as experimental organisms in developmental biology but higher fungi have been neglected. Basidiomycetous fungi have considerable three dimensional structures and these organisms can be used for investigating differentiation and integration in multicellular organisms. I have concentrated my experiments on the initial events of photomorphogenetic developments in Coprinus congregatus.; There have been many reports that phenoloxidases are correlated with development in many fungi. C. congregatus, one of mushroom-forming basidiomycetes, which requires light for its development also has phenoloxidases.; In C. congregatus, there are two sets of membrane-associated phenoloxidases (POX I and POX II) which are differentiated by their isozyme patterns, and each enzyme set consists of two different substrate specific enzyme proteins; o-tolidine reacting enzyme (TRE), and DOPA reacting enzyme (DRE). POX I which is localized by a protoplast- concanavalin A technique by using a new solidifying agent, Pluronic Polyol F 127, instead of agar appears in the vegetative hyphae, and POX II appears at the early primordial stage on agar and at the sclerotial stage of liquid shake cultures. Inhibition of POX I with the enzyme inhibitors inhibits mushroom formation as well as melanization of the vegetative hyphae at concentrations which do not inhibit the vegetation growth. POX I deficient mutants do not form mushrooms or melanins, and the mutants show abnormal nuclear migration patterns. POX II has two roles; possibly cementing the adjacent hyphae during the actual three dimensional structure formation, and melanizing mushrooms and sclerotia. The possible roles of POX I in the light reception complex and in melanin formation, the function of melanin, and possible roles of postulated post-translational modifying enzymes which regulate the phenoloxi dases, nuclear migration patterns, and self-nonself recognition mechanism are discussed. |
