ANTIBIOTIC GROUPS 183 



a 1 . Yellowish red. 



Microcin B 

 b 1 . Highly unstable fatty acid. 

 Mycomycin 

 c. Basic. 



a 1 . Colorless, water-soluble. 



Streptothricin group 

 See group B, p. 182. 



2. Active mainly against gram-positive bacteria. 



a. Acid. 



a 1 . Containing no nitrogen. 



Nigericin 

 b 1 . Containing nitrogen. Light absorption maximum at 240 

 and 267 m/x. 



Musarin 

 c 1 . Incompletely described substances similar to musarin. 



Helixin 



Endomycin 



b. Basic, red pigmented. 



Actinomycin group 

 See group A, p. 179. 



c. Basic, white . . Camphomycin 

 II. Active only against fungi. 



1. Rather wide antifungal spectrum; can be differentiated by their 

 spectrum of light absorption. 



a. Light-absorption maxima at 290, 305, and 316 m/*. 



Fungicidin group 



Nystatin 



Antimycoin 



Chromin 



Rimocidin 



b. Light-absorption maxima at 360, 380 and 404 m/z. 



Ascosin 

 Candicidin 



c. Light-absorption maxima at 240, 290, 335, 355, and 372 m/*. 



Fradicin 



d. Light-absorption maxima at 233 and 320 m/x. 



Antimycin A 



3. No typical light-absorption spectra or none recorded, 

 a. Wide antifungal spectrum. 



a 1 . Containing no nitrogen, insoluble in water. 

 Mycelin 



