1 If. 



THE ACTINOMYCETES, Vol. II 



actinomycetes are streptothricins ; here be- 

 long various related compounds, such as 

 streptin, streptolin, actinorubin, and anti- 

 biotic 136. 



The most important species belonging to 

 this series are S. lavendulae and S. venezuelae, 

 organisms producing streptothriein and 

 chloramphenicol respectively. 



S. lavendulae comprises organisms ex- 

 tremely variable in nature. Many of them 

 give rise, on cultivation, to different variants 

 or mutants. Some of these variants produce 

 a blue diffusible pigment on glucose-peptone 

 agar; others form a brown pigment. The sub- 

 strate mycelium of the blue pigment-forming 

 variants is pale blue, with scattered, small 

 pinpoint areas of deep blue. Upon complete 

 sporulation, the substrate growth becomes 

 covered with the characteristic lavender- 

 colored aerial mycelium; occasional sunken 

 areas have a slightly bluish tinge; the reverse 

 of the substrate growth is cream-colored 

 except for the small blue spots. Other vari- 

 ants produce a colorless to cream-colored 

 substrate growth free of any blue pigment 

 whatsoever; a brown diffusible pigment ap- 

 pears later, and the growth becomes covered 

 with thick lavender-colored mycelium. The 

 two types of variants are stable in nature. 

 Some variants may lose the capacity to 

 produce aerial mycelium. 



S. venezuelae, as well, gives rise to a num- 

 ber of variants. Two strains were isolated 

 and found to be similar to S. lavendulae in 

 their cultural and physiological properties, 

 although they differed in their ability to 

 utilize various carbohydrates. Streptomyces 

 venezuelae utilizes arabinose, rhamnose, 

 xylose, lactose, and fructose; S. lavendulae 

 has either no effect or only a limited effect 

 upon these carbohydrates. The former also 

 differs from the latter in its sensitivity to 

 actinophage and in various serological re- 

 actions. 



Streptomyces venezuelae was described as 

 having a thin-walled substrate mycelium, 

 colorless, hyaline, monopodially branched. 



the hyphae varying in diameter from 0.9 to 

 1.8 n and the branches growing to about 150 

 ix in length. The aerial mycelium appears 

 lavender under the microscope, thick-walled, 

 generally not much branched, straight or 

 slightly and irregularly curved, not forming 

 spirals, individual hyphae arising frequently 

 from the primary mycelium at the surface 

 of the substrate. The color of the colonies, 

 when viewed on agar without magnification, 

 is gray to light tan or pink, but not lavender. 

 The upper portions of the aerial hyphae 

 divide into chains of spores. These are oval 

 to oblong 0.4 to 0.9 by 0.7 to 1.6 M - Individ- 

 ual spores are colorless at maturity, but in 

 mass appear tan to gray when viewed with- 

 out magnification. 



Okami (1956) made a comparative study 

 of the organisms commonly included in the 

 Lavendulae series on the basis of the color of 

 the aerial mycelium and certain other char- 

 acteristics. He found that eight cultures, 

 notably the streptothricin-producing forms, 

 possessed the following properties which he 

 considered as standard for the series. 



a. Aerial mycelium pink-lavender color 

 when grown on yeast extract-glucose 

 agar. 



b. Brown pigment when grown on yeast 

 extract -glucose agar. 



c. Very sensitive to chlortetracycline and 

 chloramphenicol; relatively sensitive to 

 streptomycin; relatively resistant to 

 neomycin; and resistant to strepto- 

 thriein. 



d. Utilize: glucose, galactose, maltose, 

 mannose. Do not utilize: arabinose, 

 fructose, lactose, mannitol, raffmose, 

 rhamnose, sucrose, xylose. 



e. They show certain growth-inhibiting 

 effects (Tables 24 and 25). 



On continued cultivation for 40 years on 

 artificial media, the original 1915 isolate of 

 S. lavendulae (No. 3330) lost many of its 

 characteristic propert ies : 



1. It no longer produced any aerial my- 

 celium. 



