CHARACTERIZATION OF STREPTOMYCES SPECIES 



(17 



case of natural overlapping between man- 

 made concepts of genera and species or the 

 improper labeling of cultures. Gordon and 

 Mihm (1957) emphasized that il is easy to 

 understand how a culture of A", asteroides 

 that formed acid-fasl coccobacilli, rods, and 

 short filaments and whose growth was 

 heavy, finely to coarsely wrinkled, cream- 

 colored to orange, and without noticeable 

 aerial hyphae, could be mistaken for a Myco- 

 bacterium. A culture of N. asteroides, how- 

 ever, that produced nonacid-fast , long, tan- 

 gled filaments and a cream-colored, pale 

 yellow, or beige growth thickly covered with 

 whitish aerial hyphae, could just as easily be 

 accepted as a Streptomyces. 



Numerous other studies have been made 

 of the micromorphology of the various spe- 

 cies and groups of Streptomyces, as in the 

 work of Burkholder et al. (1954), Hesseltine 

 et al. (1954), Ktt linger et al. (1958), Flaig 

 and Kutzner (1960), and others. 



C. Spores. The spores, also called conidia, 

 produced from, or in, certain hyphae of the 

 aerial mycelium, or the "sporogenous hy- 

 phae," may be oblong, oval, or spherical. 

 Krassilnikov (1949) attached great impor- 

 ance to this character, as determined by the 

 light microscope, as a diagnostic feature. 

 Kriss et al. (1!»4.">) were the firsl to use the 

 electron microscope for study of spores of 

 Streptomyces. This was followed by the work 

 of Carvajal (1946); Kiister (l<):>:i); Flaig et 

 al. (1952, 1955, L958); Baldacci and Grein 

 (Hi.").)); Grein (1955); Vernon (l ( .).V>); and 

 others. Flaig et al. (1952) found that the 

 spores of some strains had smooth surfaces 

 while others had spiny surfaces. They later 

 detected spores with hairy and warty sur- 

 face.-; the nature of the nitrogen source in- 

 fluenced the appearance of the spore surface. 

 organic nitrogen favoring spine formation. 

 Kiister (1955) classified Streptomyces spores 

 into two group.-: (a) those producing a 

 smooth surface and (b) those having a rough 

 surface. Each of these groups was divided 



into three subgroups, based on shape of the 

 spores. Thus I here are Spores with smooth 

 surface.-, with spines, with hairs, or with 

 warty protuberances, and -pore- that are 

 globose, long-ovoid, and cylindrical. 



On the basis <>f a system of classification 

 that they had outlined, Baldacci and Grein 

 ( 1'.).").")) examined 50 strain- of -t reptomycetes 

 with the electron microscope. Three types 

 of spores were recognized: (1) Oval, more or 

 less transparent spores; these were either 

 smooth or rough, the latter having a spiny 

 or hairy surface 1 ; the spines were either short 

 and thick or long and thin. (2) Round, 

 opaque spores, usually smooth. (3) Poly- 

 hedral spores, smooth and transparent, or 

 slightly curved, wrinkled, and opaque. The 

 form of the spores was constant for the series 

 in Baldacci's system. It can hardly be used, 

 however, as a species characteristic. A cor- 

 relation was observed (Pridham, L959) be- 

 tween spore characteristics and sporophore 

 morphology (Table 6). 



According to l'reobrajeitskava et al. ( 1!).")!), 

 ]'.)(')()), strains within one species as a rule 

 have a similar type of spore surface. Cultures 

 with a white, yellow, greenish-yellow, yellow- 

 gray, pink, or lilac mycelium have smooth 

 spores; those with a bluish aerial mycelium 

 have spiny and hairy spores, and species 

 with a gray aerial mycelium have spores of 

 all types. The diagnostic value of spore sur- 

 face characteristics was found to be dissimi- 

 lar for the various sections. The correlation 

 between the gray and bluish species and the 

 character of the surface of the spores was 

 considered as insignificant. Tresner <l al. 

 (1960) also emphasized the importance of 

 spore surface in classifying species of Sin />- 

 tomyces; size and shape of spores of mosl 

 species were considered of limited usefulness 

 in taxonomic different iatioti. 



Lechevalier and Tikhonienko I 1959 re 

 ported that the spores of S. viridochromo- 

 genes were mostly elongated and those of S. 

 violaceus, spherical. The spines formed by 



