[Morphofunctional study of the development of Actinomyces aureofaciens under conditions of regulated and unregulated fermentation].

Actinomyces aureofaciens producing tetracycline and its inactive proactinomyces-like variant were studied by electron microscopy during their growth under conditions of regulated and non-regulated fermentation. The ultrastructure of the active variant changed: the cell wall and ribosomes underwent modification, amorphous electron-transparent structures appeared, and tubular membrane structures were formed. No changes were found in the inactive variant. When Act. aureofaciens grows in conditions of non-regulated fermentation, it shows rapid disintegration and autolysis; then, wide fragmented hyphae are formed. The morphology of these hyphae is similar to that of spore forming hyphae of the aerial mycelium. Viable hyphae exist for a long time if the active culture grows in conditions of regulated fermentation with periodic addition of nutrient substances. Amorphous electron-transparent structures, apparently of the antibiotic nature, are formed in the hyphae and liberated into the medium.