REQUIREMENTS OF INSECTS 



amount of nicotinic acid in leaf tissue was generally higher in trisoniic 

 than in disomic maize. ^ This increase is probably due to synthesis 

 from tryptophan, which increased the nicotinic acid content of corn 

 embryos when added to sterile cultures on which they were grown ^ 

 and that of cabbage, broccoli and tomato leaves when supplied through 

 the petioles.^ Tryptophan was apparently not converted into nico- 

 tinic acid by haricot beans. ^ 



References to Section i6 



1. J. Bonner, Plant Physiol., 1938, 13, 865 



2. G. R. Noggle and F. L. Wynd, Bot. Gaz., 1942, 104, 455 ; R. B. 



Bahme, Science, 1949, 109, 522. 



3. L. J. Andus and J. H. Quastel, Nature, 1947, 160, 222. 



4. A. W. Galston, /. Biol. Chem., 1947, 169, 465. 

 4a. L. J. Andus, Nature, 1948, 162, 811, 



5. P. R. Burkholder, Science, 1943, 97, 562. 



6. N. H. Giles, P. R. Burkholder, I. McVeigh and K. S. Wilson, 



Genetics, 1946, 31, 216. 



7. A. Nason, Science, 1949, 109, 170. 



8. F. G. Gustafson, ihid., 1949, 110, 279. 



9. T. Terroine, Compt. rend. Soc. bioL, 1948, 227, 367. 



17. NICOTINIC ACID REQUIREMENTS OF INSECTS 



Nicotinic acid was found to be essential for the development of the 

 fruit fly, Drosophila melanogaster,^ of the moths, Galleria mellonella ^ 

 and Ephestia elutella,^ and of the beetles, Ptinus tectus,^ Triholium con- 

 fusum ^ and Silvanus surinamensis,^ but not of the two beetles, 

 Sitodrepa panicea and Lasioderma serricorne.^ When the larvae of 

 these last two insects were sterilised, however, normal development 

 did not take place until several members of the vitamin B complex, 

 including nicotinic acid, were added to the diet.* This indicated that 

 the reason why certain insects do not require endogenous sources of 

 these vitamins is that they are provided by the intracellular sjmibionts. 

 The larvae of the mosquito, Aedes aegypti, required nicotinic acid as 

 well as other vitamins to permit growth to the fourth instar.^ 



References to Section 17 



1. E. L. Tatum, Proc. Nat. Acad. Sci., 1941, 27, 193. 



2. D. L. Rubinstein and L. A. Shekun, Nature, 1939, 143, 1064. 



3. G. Fraenkel and M. Blewett, ibid., 1943, 151, 703. 



4. G. Fraenkel and M. Blewett, ibid., 1943, 152, 506 ; Biochem. J., 



1943, 37, 686; Proc. Roy. Soc. B., 1944, 132, 212. 



5. L. Golberg, B. de Meillon and M. Lavoipierre, /. Exp. Biol., 



1945. 21, 90. 



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