Howard Berg

Bacterial Motility and Behavior

Principle Investigator
Rowland Institute at Harvard
Harvard University
100 Edwin H. Land Blvd.
Cambridge, MA 02142
Tel: 617-497-4606/4656
Fax: 617-497-4627
Website: Bacterial Motility and Behavior

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. E coli in Motion. New York: Springer-Verlag. 2003

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

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

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

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

  • 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.

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