ZAVADOVSKY, MIKHAIL MIKHAYLOVICH

(b.Pokrovka, Kherson guberniya [now Kirovograd], Russia, 29 July 1891; d. Moscow, U .S.S.R. , 28 March 1957)

biology.

Zavadovsky graduated in 1914 from the natural sciences section of the Faculty of Physics and Mathematics of Moscow University, with a dissertation on the lipoid semipermeable covering of the eggs of Ascaris megalocephala. From 1915 to 1918 he was assistant to N. K. Koltsov at the Moscow University for Women and, after receiving his master’s degree in 1918, became privatdocent of experimental biology at Moscow University. He worked at the Askania Nova Zoo and at the University of the Crimea from 1919 to 1921, when he resumed teaching at Moscow University. From 1922 to 1924 he was professor at the Karl Liebknecht Institute of National Education in Moscow.

He assumed the post of head of the department of general biology at the Second Moscow State University (1924-1928) and from 1925 was director of the Moscow zoo, where he organized a laboratory of experimental biology. In 1929 he became head of the laboratory of the physiology of growth of the Institute of Livestock Breeding of the Lenin All-Union Academy of Agricultural Sciences, and from 1930 to 1948 he headed the department and laboratory of the dynamics of development at the First Moscow State University.

In his studies of the developmental conditions of parasitic worms (Ascaris, Enterobius, Trichostrongylidae) Zavadovsky paid special attention to the importance of external factors, such as oxygen and the chemical constitution of the environment, with the aim of developing measures to combat infection in man and domestic animals. He published about forty articles on experimental parasitology.

Zavadovsky also analyzed the development of sexual characteristics. Detailed studies of the effects of castration and the transplantation of sex glands in chickens led him to conclude that some of the secondary sexual characteristics depend on their development in the hormones of the sex glands and that some are independent of it. These results were confirmed in his studies of ducks, pheasants, antelopes, and horned cattle. The similarity of gelded males and spayed females testified to the equipotentiality of the soma of both sexes.

Zavadovsky established that the monosexuality of female birds and the bisexuality of the maleand the opposite among mammals and amphibians-correspond to the distribution of sex chromosomes: XY in female and XX in male birds, and the reverse among mammals and amphibians. Zavadovsky investigated the interrelationships between secondary sexual characteristics and the sex glands and studied the interaction of the endocrine glands. He concluded that ± a mutual influence exists: an organ that stimulates another also is inhibited by it. This was an important application to biology of the cybernetic principle of positive or negative feedback.

On the basis of his study of the sexual cycle of laboratory and farm animals, Zavadovsky suggested the possibility of hormonal stimulation of multiple pregnancy in sheep, by introducing the blood serum of a mare in foal. The applications of his proposal were especially important in the breeding of Karakul sheep.

BIBLIOGRAPHY

I. Original Works. Zavadovsky’s writings include “O lipoidnoy polupronitsaemoy obolochke yaits Ascaris megalocephala” (“On the Lipoid Semipermeable Covering of the Eggs of Ascaris megalocephala”) in Uchenye zapiski uni\versiteta im. Shanyavskogo 1-2 (1914-1915); pol i razitie ego priznakov. K analizuformoobrazovania u zhivotnykh (“Sex and the Development of its signs. Toward an Analysis of Formation in Animals” Moscow,1922); Ravnopotensialna li soma samtsa i samki u ptits i mlikopitayushchikh? (“Are the Male and Female Soma Equipotent in Birds and Mammals?; der Geschlechtsdrusen ab?” in Biologia generalis2 (1926),631-638, “The Bisexual Nature of the Hen and Experimental Hermaphroditism in Hens, “ibid3 (1927); and” Priroda skorlupy yaits askarid raznykh vidov “(“The Nature of the Shells of the Eggs of Various Kinds of Ascarids”). in Trudy Laboratorii eksperimentalnoi biologi Moskovskogo zooparka4 (1928),201-207; and Vneshnie i vnutrennie faktory razvitia(“External and Internal Factors of Development “; Moscow, 1928).

See also Dinamika razvitia organizma (“Dynamics of Development in the Organism” .Moscow 1931); “Printsip ±vzaimoodeystvi v razvitii osobi” (“Principle of ±Mutual Interaction in the Development of the Individual”), in Uspekhi sovremennoi biologi2 (1933), 86-103; “Upravlenie polovym tsiklom krolikov, ovets, i korov” (“Control of the Sexual Cycle of Rabbitis, Sheep, and Cows”), in Trudy Po dinamike razvcitiya11 (1939), 15-24; “Opyt eksperimentalonogo mnogoplodia ovets” (“An Experimental Attempt at Multiple Pregnancy in Sheep”), ibid94-112; Estestvennoe i eksperimentalnoe mnogoplodie korovoo (“Natural and Experimental Multiple Pregnancy in Cows” . Alma Ata,1947);and Teoria i prakitika gormonalnogo metoda stimulyatsii mnogoplodia selskokhozyaystvennykh zhivotnykh(“Theory and Practice of the Hormonal Method of Stimulating Multiple Pregnancy in Agricultural Animals” ;Moscow,(1963)

II. Secondary Literature. See N. I. Vavilov, “Prof. M. M. Zavadovskomu (Po povodu 20–letia ego nauchnoy deyatelnosti)” (“To Prof. M.M. Zavadovsky [On the 20th Anniversary of His Scientific Career]”).in Trudy po dinamike razvitiya10 (1935), 9-11.

L. J. Blacher