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George F. Oster
In Memoriam

George F. Oster

Professor of Environmental Science, Policy, and Management, Emeritus

UC Berkeley
George Frederick Oster, who died in Berkeley on April 15, 2018, was a pioneer in the fields of biophysics and mathematical biology. George fostered contemporary understanding of biological molecules, cells, and tissues as mechanochemical machines.

George was born on April 20, 1940, in New York City.  After finishing high school on Long Island, N.Y. in 1957, George attended the U.S. Merchant Marine Academy at Kings Point, N.Y. and spent a year at sea. In 1961, he continued his studies at Columbia University and in 1967 received a Ph.D. in nuclear engineering. Realizing that science attracted him more than engineering, he pursued another doctoral degree in biophysics from the University of California, Berkeley. Shortly after starting, he met Aharon Katchalsky, a pioneering Israeli scientist, who recognized George’s talent and persuaded him to work together on the thermodynamics of biological networks. With Katchalsky, George did his postdoctoral work at the Weizmann Institute in Israel and also at the University of California, Berkeley. George fell in love with the vibrant political and scientific scene of the Berkeley campus in the late 1960s and also with the natural beauty of the Bay Area. He joined the Department of Mechanical Engineering as a faculty member and stayed at Berkeley from 1970 for the rest of his life, changing departments as his insatiable curiosity drove him from one biological problem to another.

George Oster was fortunate to be a part of a generation of scientists who had the audacity  to move freely between disciplines. Early in his career, he worked on pathbreaking mathematical models of population dynamics and developed the first detailed theories of caste evolution among social insects (with Edward O. Wilson) as well as theories of bifurcations to a hierarchy of periodic oscillations and chaos in simple ecological models (with Robert May).

At some point in life, every great scientist discovers a unique point of view that reveals a hidden natural order that was previously unknown. George made his discovery in the late 1970s to early 1980s, when he realized that biological molecules, cells, and tissues can be seen as intricate mechanochemical machines, in which mechanical forces, chemical reactions, and stochastic Brownian movements are intimately coupled. For the next 35 years of his remarkable career, George unraveled the laws of this mechanochemical coupling, which led to a deep understanding of the physics of the cell.

With Garrett Odell, James Murray, and others, George developed mechanical models of morphogenesis. These models revealed how forces and deformations of the cell cytoskeleton integrate with chemical and genetic signals to shape tissues in the development of organisms. With Alan Perelson, George proposed that the swelling of the cytoskeletal gel can drive protrusions at the cell front, laying the foundation for quantitative studies of cell motility. Having addressed populations, then tissues, then individual cells, he next looked deeper to find problems related to molecular motors — fundamentally important proteins moving on polar cytoskeletal fibers and exerting forces on a pico-Newton scale. George realized that these biological machines operate in a realm that is dominated by thermal fluctuations, and that nature had found a way of turning thermal noise into a unidirectional, ratcheted Brownian motion through physical-chemical reactions which generate forces and movements. This discovery led to a dramatic breakthrough in our understanding of how energy transduction occurs in all living organisms. This work has also spurred an intense amount of interest in the broader statistical mechanical community to study the interplay between random thermal fluctuations and directed motion.

In the 1990s, George together with Charlie Peskin and George’s students, postdocs, and experimental collaborators, made another breakthrough: he discovered how to go from abstract ratchet models to mechanochemical models by using structural, biochemical, and genetic analyses of molecular motors. During that decade, George established an important shift from conceptual to detailed and predictive mathematical models of biological systems. This new way of modeling is best exemplified through two papers in Nature about the reverse-engineering of ATP synthase. In this work, George, together with Hongyun Wang and Tim Elston, integrate mathematical models with biophysical data to account for minute details of the motor’s behavior. Luckily, this theoretical work coincided with a revolution in the experimental field brought about by usage of optical traps. Many of their theoretical predictions were tested and inspired new experiments. It would not be an exaggeration to say that George, more than any other physicist or mathematician, inspired our current knowledge of molecular motors.

George was one of the first biophysicists who ‘married’ experiments and theory by developing computational models of a bewildering variety of molecular machines –  a kinesin motor, a flagellar rotary motor, RNA polymerase and protein translocation motors, a ‘one-shot’ actin polymerization motor, and a ‘snot-gun’ motor of bacterial gliding. He wrote influential papers on cell membrane mechanics, neural pattern formation, endocytosis, and actin-based protrusions, George taught us how to choose which biological systems are ripe for modeling. He also showed us how to pry open the secrets of molecular and cellular machines by combining experimental observations with physical intuition, engineering principles, and mathematical tools. He established the now accepted approach to solving biological puzzles through iterative cycles of modeling and experimentation instead of stubbornly holding onto a model in the face of ‘inconvenient’ experimental data. His work on reexamining the workings of bacterial flagellar motor and myxobacterial gliding in the face of new experimental evidence stand as a testimony to this approach.

George received wide international recognition. He was a Guggenheim and a MacArthur Fellow. He was awarded the Weldon Memorial Prize by Oxford University, the Winfree Prize by the Society for Mathematical Biology, and the Raymond and Beverly Sackler International Prize in Biophysics. He was elected to the National Academy of Sciences in 2004.

George Oster often said that people are what is most important in science. He always pulled together a very interdisciplinary set of students and postdocs as diverse as molecular cell biology, physics, mathematics, engineering and chemistry. He inspired so many with his brilliance, enthusiasm, and passion for science and life. Generations of students, friends, and colleagues will never forget the fountains of ideas gushing out of him in the Brewed Awakening café on Euclid Avenue at the edge of the Berkeley campus, where George held informal group meetings almost every morning. George was also a generous mentor both professionally and personally to his students and postdocs in their advancement. He also served for more than two years on the Berkeley Division of the Academic Senate’s Library Committee (2008-2011), helping colleagues from across campus to see how digital tools where changing the way the academy expanded knowledge. He retired from UC Berkeley in 2016.

George was a warm man who radiated the joy of doing science. He was at the peak of his powers when Lewy-Body Parkinson's disease overcame him. He  is sorely missed by the scientific community and by his many friends. He is survived by his daughter Liya Oster and his sister Susan Best and her children.

Alex Mogilner
Kranthi Kiran Mandadapu