FAMILY STREPTOMYCETACEAE 929 



FAMILY III. STREPTOMYCETACEAE WAKSMAN AND HENRICI.* 



(Jour. Bact., 46, 1943, 339.) 



Vegetative mycelium not fragmenting into bacillary or coccoid forms. Conidia 

 borne on sporophores. Primarily soil forms, sometimes thermophilic in rotting 

 manure. A few species are parasitic. 



Key to the genera oj family Streptomycetaceae. 



I. Conidia produced in aerial hyphae in chains. 

 Genus I. Streptoynyces, p. 929. 

 II. Conidia produced terminally and singly on short conidiophores . 

 Genus II. Micromonospora, p. 978. 



Genus I. Streptomyces Waksman and Henrici. 



{Streptothrix Cohn, Beitr. zur Biol, der Pflanzen, /, Heft 3, 1875, 186; not Strep- 

 tothrix Corda, Prachtfiora Europaescher Sohinmielbildung, 1839; Nocardia 

 Wright, Jour. Med. Research, IS, 1905, 349; Nocardia Winslow et al.. Jour. Bact., 

 2, 1917, 554; not Nocardia Trevisan, I generi e le specie delle Batteriacee, 18S9, 

 9; Cohnistreptothrix (Group I) 0rskov, Investigations in the Morphology of the Ray 

 Fungi. Copenhagen, 1923, 147; not Cohnistreptothrix Pinoy, in Li^gard and Lan- 

 drieu. Bull. Soc. Opht., U, 1911, 253 and Bull. Inst. Past., 11, 1913, 929; Aerothrix 

 Wollenweber (in part), Ber. deut. Bot. Gesel., 39, 1921, 26; Euactinomyces Langeron 

 (in part), Nouv. Traits de Med., 4, 1922; Waksman and Henrici, Jour. Bact., 46, 

 1943, 339.) 



Organisms growing in the form of a much-branched mycelium with a typical aerial 

 mycelium. Conidiospores formed in chains. Aerobic. Saprophytic soil forms, less 

 commonly parasitic on plants or animals. 



This genus can be divided, on the basis of the structure of sporulating hyphae, into 

 five groups : 



Group 1. Straight sporulating hyphae, monopodial branching, never producing 

 regular spirals. 



Group 2. Spore-bearing hyphae arranged in clusters. 



Group 3. Spiral formation in aerial mycelium; long, open spirals. 



Group 4. Spiral formation in aerial mycelium; short, compact spirals. 



Group 5. Spore -bearing hyphae arranged on mycelium in whorls or tufts. 



The type species is Streptomyces albus (Rossi Doria emend. Krainsky) Waksman 

 and Henrici. 



Key to the species of genus Streptomyces. 



I. Saprophytes; psychrophilic to mesophilic. 



A. Soluble pigment on organic media faint brown, golden-yellow, or blue; 

 pigment may also be absent entirely. 



1. Pigment absent, or faint brown pigment formed at first and later lost; 



aerial mycelium abundant, white. 



1. Streptomyces albus. 



2. Pigment blue or red, when present. The red (insoluble) phase occurs 



when the reaction is distinctly acid, the blue (soluble) phase 

 when it is alkaline. 



2. Streptomyces coelicolor. 



* Revised by Prof. S. A. Waksman, New Jersey Experiment Station, New Bruns- 

 wick, New Jersey and Prof. A. T. Henrici, University of Minnesota, Minneapolis, 

 Minnesota, May, 1943. 



