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THE ACTINOMYCETES, Vol. II 



Table 19 

 Morphological and physiological properties of certain strains and one mutant of Streptomyces griseus 



* Brownish pigment produced by some strains. 

 t Mutant of this culture produced an antibiotic 



nitrogen from a variety of compounds, in- 

 cluding both inorganic and organic forms. 

 In studies of streptomycin-producing 

 strains, Carvajal (1946) characterized the 

 morphology and life cycle of S. griseus in 

 greater detail. The substrate mycelium when 

 young is well branched, typically in a mon- 

 opodial form. Transverse septa are formed 

 in virtually all cases in the delimitation of 

 the reproductive cells. Reproduction occurs 

 by means of unicellular asexual spores and 

 conidia, which are exogenously borne in 

 chains on the aerial mycelium. The spores 

 are of various shapes: barrel, oval, bean, 

 spherical, and cylindrical. Differences in 

 shape and size are found often, even 

 among the spores of the same chain. Mature 

 aerial spores often show small fragments of 

 transparent film adhering to the outside wall. 

 The spores germinate at one end or at both 

 ends, usually from the points at which they 

 are attached to the adjacent spores or to the 

 hypha. Hyphal fusions and germ tube fusions 

 also can be observed. Carvajal reported that 

 he had demonstrated a nucleus in the germ 

 lubes of S. yrixcKs in the young mycelium 



and in the developing spores. The nuclei 

 were said to be well distributed throughout 

 the cytoplasm of the mycelium; the spores 

 may be uninucleate or multinucleate. 



Gottlieb and Anderson (1947) studied the 

 course of spore germination and of develop- 

 ment of the mycelium in submerged cultures 

 of S. griseus. The exact time of spore germi- 

 nation was difficult to determine, only an 

 elongation of the spores being observed. 

 After 6 hours, the mycelium was found to 

 consist of some small hyphae and of longer 

 branched hyphae which tended to develop 

 into masses of mycelium consisting of a 

 dense solid center and a periphery of 

 branched radiating hyphae. Within '24 to 

 30 hours, the entire body of the medium 

 was filled with these mycelial clumps. The 

 culture appeared viscous at this stage. After 

 48 hours, the mycelium began to fragment, 

 and spores were produced. At 84 hours, def- 

 inite lysis of the mycelium took place; the 

 dense central core of the masses of growth 

 disintegrated into granular pieces. 



Measurement of viscosity and weight of 

 mycelium revealed an increase which reached 



