LWOFF, ANDRÉ MICHEL

LWOFF, ANDRÉ MICHEL (1902–1994), French biologist and Nobel Prize winner. Born in the Allier department, France, Lwoff became head of the Microbial Physiology Laboratory of the Pasteur Institute in Paris in 1938. Lwoff's earlier work dealt with the morphology and biology of the ciliate protozoa, and particularly the problem of the genetic continuity of cell structures. His later research dealt with the biology of viruses, the genetics of bacteria, and the mechanisms by which viruses are replicated in the course of a viral infection. During World War II he was awarded the Medal of the Resistance for his work in the French underground. After the war Lwoff and his collaborators began a study of lysogeny. Lwoff demonstrated that in this condition the bacterial cell harbors a "prophage" which is harmless to the host cell and is transmitted genetically. It can be induced by external factors, such as ultraviolet light, to become virulent, causing destruction of the host cell and liberation of infectious virus particles. This discovery led to entirely new ideas as to the evolution and biological role of viruses. Lwoff was corecipient of the 1965 Nobel Prize for medicine and physiology. Among his books are Problems of Morphogenesis in Ciliates (1950) and Biological Order (1962). He was also editor of Biochemistry and Physiology of Protozoa (3 vols., 1951–64). (Mordecai L. Gabriel)