FAMILY STREPTOMYCETACEAE 



979 



face growth in liquid medium. The 

 organism resists desiccation for at least 

 8 months. Comparison between the 

 power of resistance of the mycelium and 

 the spores, respectively, will no doubt 

 present great difficulty, because it is al- 

 most impossible to ensure that the two 

 constituents are actually detached. 

 Otherwise, the mj'celium is but slightly 

 capable of germinating, which maj^ be 

 ascertained by inoculating a water agar 

 plate liberall}' with a mixture of mycelial 

 threads and spores. While practically 

 all the spores germinate, the mycelial 

 threads were never found to form new 

 colonies . 



Vegetative mj^celium on glucose-as- 

 paragine-agar : Heavy, compact, raised, 

 pale pink to deep orange, not spreading 

 much into the medium. Spore-layer well 

 developed, moist and glistening, brown- 

 ish-black to greenish-black, this color 

 sometimes spreading through the whole 

 mass of growth. 



Gelatin is liquefied. 



Grows in liquid media as small firm 

 orange granules or flakes. 



^lilk is digested with a faintly acid 

 reaction, mostly after a previous coagula- 

 tion. 



Many strains invert sucros^e. 



Some strains produce nitrites from 

 nitrates. 



Starch is hydrolj'zed. 



Most strains decompose cellulose. 



Proteolytic actionseems stronger in this 

 than in the other species of this genus. 



Optimum temperature for growth 30° 

 to 35°C. Thermal death point of my- 

 celium, 70°C in 2 to 5 minutes. Spores 

 resist 80°C for 1 to 5 minutes. 



Habitat : Soil, lake mud and other sub- 

 strates. In addition to the above ref- 

 erences, see Erikson (Jour. Bact., 4.I, 

 1941, 299) and Umbreit and :\IcCoy (X 

 Symposium on Hydrobiology, Univ. of 

 Wisconsin Press, 1941, 106-114"). 



2. Micromonospora fusca Jensen. 

 (Proc. Linn. Soc. Xew So. Wales, 57, 

 1932, 178.) From Latin fuscus, dark. 



Vegetative m3'celium on glucose-as- 

 paragine-agar heavy, compact, orange, 

 rapidly changing to deep brown and 

 nearly black; spore-layer moist, glisten- 

 ing, grayish- to brownish-black. Deep 

 brown soluble pigment. 



Gelatin is liquefied. 



Grows in liquid media as small brown 

 granules and flakes. 



Milk is slowly digested ; no coagulation. 



Sucrose is inverted. 



Reduction of nitrates, positive or nega- 

 tive . 



Cellulose is attacked to a slight extent. 



Starch is hydrolyzed. 



Habitat: Soil. 



3. Micromonospora parva Jensen. 



(Proc. Linn. Soc. Xew So. Wales, 57, 

 1932, 177.) From Latin parvus, small. 



Scant growth on glucose-asparagine- 

 agar; vegetative mycelium thin, spread- 

 ing widel}^ into the agar, almost colorless 

 to pale pink or orange. Sporulation 

 scant, giving rise to thin grayish, moist 

 crusts on the surface. 



Gelatin is liquefied. 



Milk is left unchanged; or coagulated, 

 slowly redissolved with faintly acid reac- 

 tion. 



Sucrose not inverted. 



Nitrates not reduced. 



Cellulose not decomposed. 



Starch is hydrolyzed. 



Habitat: Soil. 



4. Micromonospora globosa Krassilni- 

 kov. (Ray Fungi and Related Or- 

 ganisms. Izd. Acad. Xauk, Moskow, 



1938, 1.34; Microbiology, U. S. S. R., 8, 



1939, 179.) From Latin globosus, spheri- 

 cal. 



A fine (0.5 to 0.8 micron in diameter) 

 monopodially branching mycelium. 

 This mycelium breaks soon into separate 

 pieces of varying length and irregular 

 outline. Conidia are formed at the ends 

 of short branches, one on each. Indi- 

 vidual branches with conidia resemble 

 grape vines. The conidia are spherical 

 1.0 to 1.3 microns; thej- arise by the 



