FAMILY I. MYCOBACTERIACEAE 



709 



month's cultivation, dissociated into a 

 stable mycobacterial culture which was dis- 

 tinct from the original culture in structure 

 and size of cells. After one day's growth, 

 cells were rod-shaped, 0.6 to 0.7 by 2.0 to 

 3.5 microns; they curved slightly and had 

 irregular contours; on salt agar and es- 

 pecially in liquid media and peptone broth, 

 cells up to 5 microns were found, often ex- 

 hibiting branching. Krassilnikov regarded 

 the history of the development of this 

 strain to be the same as that of typical my- 

 cobacteria, since these rods became shorter 

 and changed into a coccus-like stage. Rest- 

 ing forms then developed, completing the 

 cycle. Cultural and physiological properties 

 were not different from those of the original 

 culture. In view of the morphological char- 

 acteristics and the cycle of development, 

 this culture was referred to as Mijcobac- 

 terium albns Krassilnikov (1916) under the 

 name Micrococcus candicans; this organism 

 formed rod-shaped cells with side branches 

 under certain conditions (Lohnis and 

 Smith, Jour. Agr. Res., 6, 1916, 675-702). 

 Spassky (Zent. f. Bakt., I Abt., Orig., 128, 

 1933, 245) described a streptococcus which 

 gave rise to a mycobacterial strain in the 

 process of dissociation. Krassilnikov sug- 

 gests that the original culture of both these 

 organisms belonged to the genus Myco- 

 coccus. 



Source: Isolated from soil. 



Habitat: Infrequently found in soil. 



lb. IMycococcus albus subsp. lactis Krassil- 

 nikov, 1941. (Guide to the Actinomycetes, 

 Izd. Akad. Nauk, U.S.S.R., Moskau, 1941, 

 125.) 



lac'tis. L. noun lac milk; L. gen. noun 

 lactis of milk. 



Morphological and cultural characteris- 

 tics are the same as those of Mycococcus 

 albidus. 



Gelatin: No liquefaction (two months). 



Milk: Acid; rapid coagulation. No pep- 

 tonization within 30 days. Coagulation ap- 

 parently takes place through the production 

 of acid in a manner similar to that of the 

 lactic acid bacteria. 



Sucrose is inverted. 



Acid from glucose and lactose; slight acid 

 from sucrose. 



Starch weakly hydrolyzed. 



Comment : Krassilnikov regards as closely 

 related to this species a culture described by 

 Lieberman (1935) under the name Strepto- 

 coccus lactis. 



Source: Isolated from soil. 



Habitat: Infrequently found in soil. 



2. Mycococcus ruber Krassilnikov, 1938. 

 (Microbiologia (Russian), 7, Part I, 1938, 

 349.) 



ru'ber. L. adj. ruber red. 



Original description supplemented by 

 material from Krassilnikov (Guide to the 

 Actinomycetes, Izd. Akad. Nauk, U.S.S.R., 

 Moskau, 1941, 125). 



Cells spherical, irregularly rounded, 

 slightly compressed, somewhat angular, 0.5 

 to 0.9 micron in diameter. In liquid cultures 

 there are occasionally found short rods, 0.7 

 by 0.8 to 1.0 micron, with branches; en- 

 larged cells of different shapes are also 

 found. In old cultures are found resting cells 

 which germinate in a mannei similar to that 

 of the spores of actinomycetes. 

 Not acid-fast. Gram-positive. 



Gelatin: No liquefaction. 



Colonies: Dough-like consistency; 

 smooth; weak shine. Colonies dark brown, 

 rose, red-orange or, frequently, orange. A 

 culture may show different pigmentation on 

 different media. Pigment not soluble. 



Milk: No coagulation or peptonization. 



Sucrose not inverted. 



Sucrose and organic acids (acetic and 

 citric) are utilized as sources of carbon. 



Starch : No hydrolysis or weak hydrolysis 

 with a clear zone only under the colonies. 



Nitrites not produced from nitrates. 



Nitrates and ammonium salts are readily 

 utilized as sources of nitrogen. 



Some strains produce good growth on 

 paraffin. 



Some strains grow well in high concentra- 

 tions of salts, such as 10 per cent NaCl and 

 10 to 20 per cent sodium sulfate. 



Resistant to desiccation. 



Comments: Krassilnikov isolated several 

 strains which could be distinguished on the 

 basis of shades of pigmentation of the colony 

 and by the size of the cells. Strains Nos. 3 

 and 5 were blood-red on all media; cells 0.6 

 to 0.9 micron, frequently 1.0 micron, in 

 diameter. Strain No. 45 was rose-red, red or 



