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Studies on the Structure of Streptomyces Griseus

1946; Taylor & Francis; Volume: 38; Issue: 5 Linguagem: Inglês

10.1080/00275514.1946.12024080

1557-2536

Fernando Carvajal,

Microbial Natural Products and Biosynthesis

SUMMARY1. Structural studies of active and inactive strains of S. griseus were made with light and electron microscopes.2. The vegetative mycelium when young is coenocytic and well branched typically in a monopodial form. Transverse septa are formed in practically all cases in the delimitation of the reproductive cells. Also septa occasionally were observed in the older mycelium.3. The basal portions of new mycelial branches were often seen to be constricted.4. The reproduction of S. griseus occurs by means of unicellular, asexual spores (conidia) which are exogenously borne in chains on the aerial mycelium.5. The spores of S. griseus were found to be of various shapes: barrel, oval, bean, spherical, and cylindrical. Differences in shape and size were found often, even among the spores of the same chain.6. The progressive stages in the development of sporogenous hyphae can be observed easily in a one to three day old culture on a good sporulation media.7. The aerial sporogenous hyphae showed some differences in morphology among strains growing upon the same medium. Differences were found among active strains, as well as among inactive strains.8. Mature aerial spores often show small fragments of transparent film adhering to the outside wall.9. The spores of S. griseus usually germinate at one or both ends, usually from the points at which they were attached to the adjacent spores or to the hypha. Rarely do they germinate by more than two germ tubes.10. Hyphal fusions and germ tube fusions were observed.11. The nucleus of S. griseus may readily be demonstrated in the germ tubes, young mycelium, and in the developing spores. The nuclei are well distributed throughout the cytoplasm of the mycelium. The spores may be uninucleate or multinucleate.12. Spore formation of other species of Streptomyces was very similar to that of S. griseus.13. The reproductive processes of most species of Streptomyces are far more highly developed than those of any of the bacteria.The writer gratefully acknowledges the assistance of Dr. Seth Pope for helpful criticism of the manuscript and of Mr. G. B. Levy and Mr. Denman Shaw for the technical photographic help and the operation of the electron microscope.