VI. BIOGENESIS 533 



incubating corn embryo. Gustafson"^ found that tryptophan increased, 

 slightly, the nicotinic acid content of broccoli, cabbage, and tomato leaves. 

 Banerjee and Banerjee"^ found that tryptophan increased nicotinic acid 

 in germinating Phaseolus mungo seeds, although Terroine"^ could demon- 

 strate no such relationship in Phaseolus multiflorus embryos. 



c. Insects 



Neither TriboUum confusum nor Tenebrio molitor can use tryptophan in 

 place of nicotinic acid.^^^ "Germ-free" Drosophila also require preformed 

 nicotinic acid and cannot synthesize it from tryptophan."^ 



d. Microorganisms 



Davis et al}^^ have reported that a tryptophan-nicotinic acid relation- 

 ship exists in Xanthomonas pruni very similar to that in Neurospora crassa- 

 Tryptophan can replace nicotinic acid for the growth of the fungus Tri- 

 chophyton equinumP^ Schopfer and Boss^^^ found that 2-methyl-l,4-naph- 

 thoquinone inhibits growth and nicotinic acid synthesis in Phycomyces 

 blakesleeanus, an effect reversible by tryptophan, kynurenine, anthranilic 

 acid, indole, nicotinic acid, and nicotinamide. Whether this indicates a 

 tryptophan-nicotinic acid conversion mechanism in this fungus is not yet 

 clear. Kidder et al.^^^ could demonstrate no tryptophan-nicotinic acid re- 

 lationship in the animal microorganism Tetrahymena. 



It is well known that many bacteria require nicotinic acid, and others 

 require tryptophan, whereas some require both nicotinic acid and trypto- 

 phan for growth. Many bacteria can synthesize both nicotinic acid and 

 tryptophan from simple inorganic molecules. However, little is known about 

 the exact mechanism of nicotinic acid biogenesis in bacteria. A tryptophan- 

 nicotinic acid interrelation in the same sense as it exists in Neurospora and 

 in animals is not known to exist in bacteria. ^^-"^-* 



>» F. G. Gustafson, Science 110, 279 (1949). 



1'^ S. Banerjee and R. Banerjee, Indian J . Med. Research 38, 153 (1950). 



ii« T. Terroine, Coni'pt. rend. 226, 511 (1948). 



117 G. Frankel and H. R. Stern, Arch. Biochcm. 30, 438 (1951). 



118 J. Schultz and G. T. Rudkin, Federation Proc. 7, 185 (1948). 



119 D. Davis, L. M. Henderson, and D. Powell, J. Biol. Chem. 189, 543 (1951). 



120 L. K. Georg, Proc. Soc. Exptl. Biol. Med. 72, 653 (1949). 



121 W. H. Schopfer and M. L. Boss, Helv. Physiol, et Pharmacol. Acta 7, C20-2 (1949). 



122 B. E. Volcani and E. E. Snell, Proc. Soc. Exptl. Biol. Med. 67, 511 (1948). 



123 P. Ellinger and M. M. Abdel Kader, Nat2ire 163, 799 (1949). 



124 P. Ellinger and M. M. Abdel Kader, Biochem. J. 44, 506 (1949). 



