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Ruth Lehmann

On April 24, 2008, Dr. Ruth Lehmann, Professor of Cell Biology and Director of the Skirball Institute at NYU Medical Center will present the 2008 Bloch Lecture. The title of her talk is How Germ Cells Find Their Niche: Stem Cell Migration in Vivo.

Dr. Lehmann studies the development of germ cells, the precursors of egg and sperm. These cells are fascinating because they are are the only animal cells that give rise to future generations, or in her own words: “Germ cells are forever”. Using Drosophila as a model system, Dr. Lehmann’s lab studies how germ cells form and are maintained and how they are guided to the gonads.

“In most organisms primordial germ cells (PGCs) are set aside early during embryogenesis”, says Dr. Lehmann. “Subsequently, PGCs migrate through the embryo, associate with the somatic gonadal cells and form the gonad. We are interested in the signals that guide germ cells through the embryo. Using genetics and live-imaging we have identified several pathways that control initiation of directionality, transepithelial migration and homing of PGCs. Surprisingly we find that pathways regulating lipid signaling and modifications play instructive guidance roles.”

Dr. Lehmann has made pioneering contributions to the field of developmental biology. As a graduate student in the lab of Christiane Nuesslein-Volhard (Nobel 1995) she discovered a group of genes that determine germ cell formation and posterior development in Drosophila. Subsequent studies showed that several of these genes also control germ cell development in vertebrates. As a member of the Whitehead Institute at MIT and a HHMI investigator she found that mislocalization of a single protein is sufficient to create germ cells at ectopic positions. In 1996 Dr. Lehmann moved to the Skirball Institute at NYU Medical Center, where she is the Director of the Helen L. and Martin S. Kimmel Center for Stem Cell Biology and Director of the Skirball Institute. There she discovered novel signaling pathways that control the guided migration of germ cells, the topic of her seminar. Dr. Lehmann has received many honors, including Foreign Associate Membership of the National Academy of Sciences

Dr. Ruth Lehmann will present the 2008 Bloch Lecture on April 24, 2008 at 12:00pm in Sherman Fairchild 102. All are welcome. Refreshments will be served.


By Jim Henle

Konrad E. Bloch was an outstanding scientist who helped shape the discipline of biochemistry in its formative years. One of the founders of biochemical studies at Harvard, he was part of the pioneer generation that included George Wald, Paul Doty, John Edsall and Frank Westheimer. Best known for his studies of cholesterol, he was awarded the Nobel Prize in Medicine or Physiology in 1964 (shared with Feodor Lynen) for investigations in the mechanism and regulation of cholesterol and fatty acid metabolism. Especially noteworthy were the studies on the biological synthesis of the molecule and, according to the Nobel Prize website, “on various aspects of terpene and sterol biogenesis…enzymatic formation of unsaturated fatty acids and…in various aspects of biochemical evolution.”

Arriving at Harvard from the University of Chicago in 1954, he was appointed Higgins Professor of Biochemistry, a position he held until his retirement in 1982. He was part of the core group at Harvard that founded the Committee on Higher Degrees in Biochemistry. With the somewhat later arrival of James Watson, Matthew Meselson, Walter Gilbert, Mark Ptashne and Guido Guidotti, Harvard had achieved a remarkably dynamic and productive core group in biochemistry and molecular biology, of which Dr. Bloch was a signal part. The late Dean Jeremy Knowles described him as “a marvelously perceptive biochemist and a wise, generous and cultivated man who forged the connections between chemistry and biochemistry. He was one of that distinguished line of European biochemists whose deep understanding of metabolism laid the chemical foundations of today’s biology.” [quoted in Harvard Gazette, Oct. 19, 2000]

Dr. Bloch was born in Neisse, then part of Germany, in 1912; he was racially excluded from his studies at Munich in 1934 upon the Nazi advent to power. His subsequent odyssey began in Switzerland, and he was spared a likely fatal return to Germany by the intervention of John Anderson, a Yale biochemist, who helped him with a visa to the US. In America, his studies resumed at Columbia; after a brief stay in Chicago, he came to Harvard.

His work was widely recognized; in addition to the Nobel, he received the US National Medal of Science, and many other awards and honorary degrees. In addition to his scientific output, he wrote intriguing popularizing works such as “Blondes in Venetian Paintings, the Nine-banded Armadillo, and Other Essays in Biochemistry”. He died in 2000, at the age of 88. In 1986, the annual Konrad Bloch lecture was inaugurated in his honor.

The author wishes to express his gratitude to Prof. Guido Guidotti for reviewing the text for accuracy.

The Bloch lecture, sponsored by Pfizer, honors Harvard faculty member and Nobel-prize recipient Konrad Bloch (1912-2000), a pioneer in the field of cholesterol and lipid metabolism.