Alexis “Saint-John Perse” Leger was born on this date in 1887. He was a French poet-diplomat, awarded the Nobel Prize for Literature in 1960 “for the soaring flight and evocative imagery of his poetry.” He was a major French diplomat from 1914 to 1940, after which he lived primarily in the United States until 1967.
Jacques Lucien Monod died on this date in 1910. He was a French biochemist who won the Nobel Prize in Physiology or Medicine in 1965, sharing it with François Jacob and Andre Lwoff “for their discoveries concerning genetic control of enzyme and virus synthesis”. Monod (along with François Jacob) became famous for his work on the E. coli lactose operon, which encodes proteins necessary for the transport and breakdown of the sugar lactose. From their own work and the work of others, he and Jacob came up with a model for how the levels of some proteins in a cell are controlled. In their model, the manufacture of proteins, such as the ones encoded within the lactose operon, is prevented when a repressor, encoded by a regulatory gene, binds to its operator, a specific site on the DNA next to the genes encoding the proteins. (It is now known that repressor bound to the operator physically blocks RNA polymerase from binding to the promoter, the site where transcription of the adjacent genes begins.) Study of the control of expression of genes in the lactose operon provided the first example of a transcriptional regulation system. Monod also suggested the existence of mRNA molecules that link the information encoded in DNA and proteins. He is widely regarded as one of the founders of molecular biology. Monod’s interest in the lactose operon originated from his doctoral dissertation, for which he studied the growth of bacteria in culture media containing two sugars.