382 



DESCRIPTIONS OF ANTIBIOTICS 



Table 43 

 Rf values of slreplothricin and related antibiotics (Horowitz and Schaffner, 1958) 

 Circular paper chromatography (1-propanol-pyridine-acetic acid-water, 15:10:3:12). 



Remarks: Since Waksman and Woodrutl' (1) de- 

 scribed streptothricin in 1942, investigators all 

 over the world have described many antibiotics 

 which have been termed "streptothricin-like" sub- 

 stances. Whether many of these have been re- 

 ported because there are comparatively large 

 numbers of actinomycetes that produce them in 

 soil, or because these substances are relatively 

 easy to produce and isolate is not clear. Never- 

 theless, despite the fact that streptothricin itself 

 has never been completely characterized chemi- 

 cally, many basic water-soluble substances have 

 been described as members of this group. As a 

 rule, such substances have the following charac- 

 teristics in common: they form amorphous hydro- 

 chlorides and sulfates, crystalline helianthates 

 and/or reineckates, are insoluble in most organic 

 solvents, and show end-absorption in ultraviolet 

 light. Many have been further characterized by 

 their reactions to qualitative organic tests, but 

 except for negative maltol and Sakaguchi reac- 

 tions (differentiating them from streptomycin) 

 their reactions to a given test vary. Certain of 

 them have hydrolysis products in common with 

 each other and with streptothricin. Racemomycin 

 B, streptolin, roseothricin, geomycin, and strepto- 

 thricin all yield /3-lysine and 2-amino 4 (1 -car- 

 boxy - 1 - hydroxy - 2 - amino)ethyl - 2 - imidazol- 

 ine ("streptolidine," "ro.seonine," or "geamine") 



on hydrolysis (19, 20, 23). These may also be pro- 

 ducts of mycothricin hydrolysis (21). Many are 

 complexes containing various closely related com- 

 ponents. Horowitz and Schaffner (22) have shown 

 by paper chromatography that some of the strep- 

 tothricin-like substances have components in com- 

 mon (Table 43). Other workers have reported that 

 actinorubin, lavendulin, roseothricin, antibiotic 

 136, and streptothricin VI contain streptothricin 

 and two or more components of streptolin (2, 3). 

 Variation in the amovmts of components in each 

 of these complexes undoubtedly accounts for the 

 difficulties that have been encountered in charac- 

 terizing and purifying them, and for the variations 

 in biological activity which have been reported. 

 Japanese workers have been especially active in 

 reporting such substances. They have attempted 

 to bring order out of chaos by dividing them into 

 two groups. The first (streptothricin II type) con- 

 tains the highly toxic, highly active type which 

 difl'uses slowly in agar. This group would contain 

 streptothricin. The .second (streptothricin I type) 

 contains those which are relatively nontoxic, less 

 biologically active, and diff'u.se readily in agar. 

 This group includes roseomycin. Like all generali- 

 zations, this one has exceptions. A description of 

 some of these antibiotics follows. For others, see 

 actinorubin, antibiotic 136, antibiotic 156, anti- 

 biotic El:, , antibiotic of ]\Iukherjee, fuscomycin. 



