FINE STRUCTURE OF SPORES IN A THERMOPHILIC ACTINOMYCETE MICROMONOSPORA VULGARIS

Abstract

Some general structural features of dormant and germinating spores of a thermophilic actinomycete, Micromonospora vulgaris, are described. The structure of these spores differs considerably from that in other actinomycetes so far reported.
The mature dormant spore of Micromonospora vulgaris is covered with multilayered integuments consisting of outer spore coat, intermediate spore coat, inner multilayered coat and cortex-like coat. The spore core is separated from the cortex-like coat by a boundary region. A net-like texture is sometimes visible in the spore core.
On germination the spore core swells. In the boundary region a plasma membrane and cell wall of the emerging cell seem to be synthesized. Ribosome granules of cytoplasm, extensive intracytoplasmic membrane systems, nuclear region and an unidentified fine granular structures appear to be visible in the germinating cell. Spore integuments show signs of degradation in the process of germination, this process being markedly in progress at the stage of emergence.