FINE STRUCTURE OF THE NUCLEOID AND INTERNAL MEMBRANE SYSTEMS OF STREPTOMYCES

Abstract

The fine structure of the substratum and aerial mycelium of a Streptomyces species, as seen in ultrathin sections, was studied by electron microscopy. Septa formed by the plasma membrane, dense peripheral bodies formed by the condensation of cytoplasmic membranes, and a primitive cytoplasmic reticulum which forms poorly defined membranes around the nucleus and vacuoles, were observed in the vegetative protoplast. Variations of the nucleoid, from a filamentous and granular structure in hyphae of the substratum to a spiral, tubular form in the developing conidiophore, are demonstrated. The origin of the tubular mat of the aerial mycelium is traced to the endomembranes of the degenerating conidiophore. No evidence of hyphal fusion or multiple nuclei was found.