Ernst D. Bergmann

Vitamin deficiencies in the housefly produced by antivitamins

Abstract The effect of antivitamins on the housefly Musca vicina (Macq.) has been investigated using an artificial diet. Larval growth was found to be severely hampered by the presence of neopyrithiamine, desoxypyridoxine, 4-aminopteroylglutamic acid, pantothenol, pantoyltaurine, 3-acetylpyridine, α -picolinic acid, pyridine-3-sulphonic acid, benzimidazole, and p -aminoacetophenone, and to a lesser extent by avidin, iso -nicotinic acid, and p -aminobenzenesulphonamide. The rate of inhibition appeared to be proportional to the level of the antimetabolites in the diet. Thiamine and pyridoxine reversed completely the effect of neopyrithiamine and desoxypyridoxine, respectively, whereas folic, pantothenic, and nicotinic acids relieved only partly the action of the corresponding antivitamins. The growth inhibitory action of avidin was overcome by biotin addition or by heating. The toxic effect of benzimidazole or p -aminobenzenesulphonamide was not relieved by adenine or p -aminobenzoic acid. On a synthetic diet consisting of casein, cholesterol, salts, nipagin M, thiamine, pyridoxine, pantothenic acid, nicotinic acid, folic acid, biotin, riboflavine, choline, and RNA, the larvae reached only 2 3 of the weight attained on the artificial diet which contained yeast extract instead of the above water-soluble growth factors. Oviposition is impeded when 4-aminopteroylglutamic acid, 3-acetylpyridine, desoxypyridoxine, neopyrithiamine, and pantothenol are added to the diet of the adult flies. Apart from growth inhbition, the vitamin deficiencies cause pathological features in larvae, pupae, and adults of the housefly.

The toxicity of Veratrum and Solanum alkaloids to housefly larvae

Abstract The high toxicity of dietary V. album to housefly larvae diminishes with increasing larval age and disappears at maturity. The retardation of growth initially caused by V. album is proportional to the concentration of the poison. The benzene-insoluble fraction of V. album is largely non-toxic, whereas the benzene-soluble fraction contains highly toxic ester alkaloids which have also been tested in pure form. The active compounds act as stomach poison. The toxicity of the ester alkaloids of Veratrum is dependent on the intactness of their molecules, their constituent alkamines being non-toxic. The more ester groups the alkaloid contains, the more toxic it is. Larval resistance to V. album develops relatively slowly. The glycosidic alkaloids of Veratrum and Solanum are practically non-toxic for fly larvae. The toxic action of protoveratrine on housefly larvae is not due to an antagonism to cholesterol.