HOWARD C. BERG
                                          Professor of Molecular and Cellular Biology  and of Physics

                                          Phone: (617) 495-0924
                                          Email: hberg@biosun.harvard.edu   www.mcb.harvard.edu

Fig.1        Fig.2      Fig3

                     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:

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

                     Berry, R.M. and Berg, H.C. (1999). Torque generated by the flagellar motor of Escherichia coli while driven
                     backwards. Biophys. J. 74: 1677-1693.

                     Samuel, A.D.T., Pitta, T.P., Ryu, W.S., Danese, P.N., Leung, E.C.W., & Berg, H.C. (1999) Flagellar
                     determinants of bacterial sensitivity to c-phage. Proc. Natl. Acad. Sci. USA 96: 9863-9866.

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

                     Ryu, W.S., Berry, R.M. & Berg, H.C. Torque-generating units of the flagellar motor of Escherichia coli have a
                     high duty ratio. Nature, in press: Jan. 27, 2000.

                     Chen, X. & Berg, H.C. Torque-speed relationship of the flagellar rotary motor. Biophys J., in press: Feb.,
                     2000.