MISCELLANEOUS NITROGEN COMPOUNDS 283 



tives, although lysergic acid also has a reduced N-methyl pyridine 

 structure. Fusaric acid is a potential wilt toxin in diseases caused 

 by Fusarium spp. and related fungi. Its production by F. vasinfectum 

 is narrowly controlled by the zinc content of the medium (287). Gib- 

 berella fujikuroi also forms dehydrofusaric acid (510). 



Viridicatin (Group V, Table 2) is a derivative of quinoline; quino- 

 linic acid is noted later (Chapter 10) as a possible intermediate in the 

 biosynthesis of nicotinic acid from tryptophan. Some strains of Peni- 

 cillium cyclopium form viridicatin, but in one it is replaced by the 

 related cyclopenin (75). 



Aspergillic acid, one tautomeric form of which is displayed in Table 

 2, represents a sixth group, derivatives of pyrazine. Gliotoxin, men- 

 tioned above as an indole derivative, also contains this grouping, as 

 does pulcherriminic acid, the iron salt of which, pulcherrimin, is the 

 red pigment of Candida pulcherrima (111, 297). Aspergillus flavus 

 forms, in addition to aspergillic acid, the compound flavocol, a diiso- 

 butyl derivative of deoxyaspergillic acid (140). 



The structure of the pyrazines strongly suggests a biosynthetic origin 

 from leucine and isoleucine (74). 



Cordycepin yields adenine on hydrolysis. Achromycin, an anti- 

 biotic of Streptomyces albo-niger, also is an adenine derivative (577). 

 Another actinomycete antibiotic, amicetin, incorporates the pyrimidine 

 cytosine (501). 



Nitrogenous quinones include the azanthraquinone chromophore 

 of the actinomycins (p. 254), cycloheximide (Table 2), and the pig- 

 ment phomazarin of Phoma terrestris (239, 303). 



Thiazolidine derivatives are represented only by the antibiotic acti- 

 thiazic acid. Evidence has been presented indicating that this may 

 act as an antimetabolite of biotin (553). 



Polyacetylenic compounds of fungi have been considered briefly 

 (Chapter 6). Of these, two — agrocybin (85) and diatetryne 1 (23) — 

 are amides and a third, diatetryne 2 (24), is a nitrile. 



Most pigments so far investigated have proved not to contain nitro- 

 gen but several do. To those already mentioned may be added as 

 examples the pigments of Trametes cinnabarina (216), Streptomyces 

 coelicolor (79a), and 5. limosus (80). 



BIBLIOGRAPHY 



1. Abbott, E. V. 1923. Soil Sci. 16: 207-216. 



2. Abderhalden, A. and Y. Teruuchi. 1906. Z. Physiol. Chem. Hoppe-Sey lev's 

 47: 394-396. 



