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Cylindrical, with hemispherical ends. Length 2.5 ± 0.6 µm, diameter 0.88 ± 0.09 µm (Darnton et al, 2007). Length/diameter ratio 1-5, depending on growth conditions (Nanninga, 1998).
Four, on average (Berg, 2003). Flagellar-bundle length (distance between back end of the cell body and distal end of bundle) 8.3 ± 2.0 µm (Darnton et al, 2007) but very dependent on conditions. Left-handed flagella have pitch ~2.5 µm and diameter ~0.5 µm, right-handed flagella have pitch ~1 µm and diameter ~0.3 µm. (Turner et al, 2000).
Speed during a run 30 ± 12 µm/s (Turner et al, 2000), 29 ± 6 µm/s (Darnton et al, 2007) and 28 ± 6 µm/s (Fukuoka et al, 2007) (but see earlier value 14 ± 4 µm/s (Berg & Brown, 1972) and finding that speed peaks in mid-log phase at 19 ± 0.6 µm/s (Staropoli & Alon, 2000)). Run lengths exponentially distributed with average ~1 s, tumble lengths exponentially distributed with average ~0.1 s (Berg & Brown, 1972). Changes in direction from run to run 58 ± 40 degrees, with the angle larger the more flagella break out of bundle (Turner et al, 2000).
Resting bias around 0.85 (Berg & Brown, 1972). Mutants have range of bias values, from 0 to 1 (see BCT for lists of test phenotypes). Wild type can detect <10 nM aspartate and respond to gradients up to 1 mM aspartate. Responses to short pulse of aspartate shows rapid rise plus overshoot (Segall et al, 1986). Adaptation time to large step increase in aspartate has characteristic time of minutes (Alon et al, 1999).
Diffusion rate ~7 x 10-6 cm2/s. Drift velocity in steep gradient of attractant ~7 µm/s (Berg & Turner, 1990). Response to attractant gradients is consistent with Weber-Fechner law e.g. gives constant bias change in exponential gradient (Dahlquist et al, 1972).
Alon, U., Surette, M. G., Barkai, N., & Leibler, S. (1999) Nature 397, 168-171.
Berg, H. C. (2003) Annu. Rev. Biochem. 72, 19-54.
Berg, H. C., & Brown, D. A. (1972) Nature 239, 500-504.
Berg, H. C., & Turner, L. (1990) Biophys. J. 58, 919-930.
Dahlquist, F. W., Lovely, P., & Koshland, D. E., Jr. (1972) Nat. New Biol. 236, 120-123.
Darnton, N. C., Turner, L., Rojevsky, S., & Berg, H. C. (2007) J. Bacteriol. 189, 1756-1764.
Fukuoka, H., Sowa, Y., Kojima, S., Ishijima, A., & Homma M. (2007) J. Mol. Biol. In press.
Mazzag, B. C., Zhulin, I. B., & Mogilner, A. (2003) Biophys. J. 85, 3558-3574.
Nanninga, N. (1998) Microbiol. Mol. Biol. Rev. 62, 110-129.
Segall, J. E., Block, S. M., & Berg, H. C. (1986) Proc. Natl. Acad. Sci. USA 83, 8987-8991.
Staropoli, J. F., & Alon, U. (2000) Biophys. J. 78, 513-519.
Turner, L., Ryu, W. S., & Berg, H. C. (2000) J. Bacteriol. 182, 2793-2801.
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