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Herchel Smith Research Professor of Physics

Howard Berg

Herchel Smith Research Professor of Physics

Professor of Molecular and Cellular Biology

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Motile behavior of bacteria

Flagellated bacteria possess a remarkable motility system based on a reversible rotary motor linked by a flexible coupling (the proximal hook) to a thin helical propeller (the flagellar filament). The motor derives its energy from protons driven into the cell by chemical gradients or electrical fields. The direction of the motor rotation depends in part on signals generated by sensory systems, of which the best studied analyzes chemical stimuli. Our research group is trying to learn how the motor works, the nature of the signal that controls the motor’s direction of rotation, and how this signal is processed by the chemical sensory system. These questions are being approached by a variety of molecular-genetic and physical techniques. The goal is an understanding of chemiosmotic coupling and sensory transduction at the molecular level.

Selected Publications

Lele, P.P., Hosu, B.G., and Berg H.C. (2013) Dynamics of mechanosensing in the bacterial flagellar motor. Proc. Natl. Acad. Sci. USA 110, 11839-11844.

Yuan, J., Branch, R, Hosu, B.J., and Berg, H.C. (2012) Adaptation at the output of the chemotaxic signalling pathway. Nature 484, 233-236.

Turner, L., Stern, A.S., and Berg, H.C. (2012) Growth of flagellar filaments of Escherichia coli is independent of filament length. J. Bacteriol. 194, 2437-2442.

Sourjik, V. and Berg, H.C. (2002) Receptor sensitivity in bacterial chemotaxis. Proc. Natl. Acad. Sci. USA 99, 123-127.

Skerker, J.M. and Berg, H.C. (2001) Direct observation of extension and retraction of type IV pili. Proc. Natl. Acad. Sci. USA 98, 6901-6904.

Turner, L., Ryu, W.S. and Berg, H.C. (2000) Real-time imaging of fluorescent flagellar filaments. J. Bacteriol. 182, 2793-2801 (2000).

Berg, H.C. (2003) The rotary motor of bacterial flagella. Annu. Rev. Biochem. 72, 19-54.

Berg, H.C. (2000) Motile behavior of bacteria. Physics Today 53 (1), 24-29.

Berg, H.C. Random Walks in Biology. Princeton: Princeton University Press. Revised 1993

Berg, H.C. E coli in Motion. New York: Springer-Verlag. 2003