• We are sorry, but NCBI web applications do not support your browser and may not function properly. More information
Logo of biophysjLink to Publisher's site
Biophys J. Nov 1977; 20(2): 193–219.
PMCID: PMC1473391

Physics of chemoreception.

Abstract

Statistical fluctuations limit the precision with which a microorganism can, in a given time T, determine the concentration of a chemoattractant in the surrounding medium. The best a cell can do is to monitor continually the state of occupation of receptors distributed over its surface. For nearly optimum performance only a small fraction of the surface need be specifically adsorbing. The probability that a molecule that has collided with the cell will find a receptor is Ns/(Ns + pi a), if N receptors, each with a binding site of radius s, are evenly distributed over a cell of radius a. There is ample room for many indenpendent systems of specific receptors. The adsorption rate for molecules of moderate size cannot be significantly enhanced by motion of the cell or by stirring of the medium by the cell. The least fractional error attainable in the determination of a concentration c is approximately (TcaD) - 1/2, where D is diffusion constant of the attractant. The number of specific receptors needed to attain such precision is about a/s. Data on bacteriophage absorption, bacterial chemotaxis, and chemotaxis in a cellular slime mold are evaluated. The chemotactic sensitivity of Escherichia coli approaches that of the cell of optimum design.

Full text

Full text is available as a scanned copy of the original print version. Get a printable copy (PDF file) of the complete article (2.5M), or click on a page image below to browse page by page. Links to PubMed are also available for Selected References.

Selected References

These references are in PubMed. This may not be the complete list of references from this article.
  • Koch AL. The adaptive responses of Escherichia coli to a feast and famine existence. Adv Microb Physiol. 1971;6:147–217. [PubMed]
  • Schwartz M. The adsorption of coliphage lambda to its host: effect of variations in the surface density of receptor and in phage-receptor affinity. J Mol Biol. 1976 May 25;103(3):521–536. [PubMed]
  • WILKINSON GN. Statistical estimations in enzyme kinetics. Biochem J. 1961 Aug;80:324–332. [PMC free article] [PubMed]
  • Adler J. Chemotaxis in bacteria. Annu Rev Biochem. 1975;44:341–356. [PubMed]
  • Berg HC. Bacterial behaviour. Nature. 1975 Apr 3;254(5499):389–392. [PubMed]
  • Berg HC. Chemotaxis in bacteria. Annu Rev Biophys Bioeng. 1975;4(00):119–136. [PubMed]
  • Koshland DE., Jr A response regulator model in a simple sensory system. Science. 1977 Jun 3;196(4294):1055–1063. [PubMed]
  • Berg HC, Brown DA. Chemotaxis in Escherichia coli analysed by three-dimensional tracking. Nature. 1972 Oct 27;239(5374):500–504. [PubMed]
  • Macnab RM, Koshland DE., Jr The gradient-sensing mechanism in bacterial chemotaxis. Proc Natl Acad Sci U S A. 1972 Sep;69(9):2509–2512. [PMC free article] [PubMed]
  • Brown DA, Berg HC. Temporal stimulation of chemotaxis in Escherichia coli. Proc Natl Acad Sci U S A. 1974 Apr;71(4):1388–1392. [PMC free article] [PubMed]
  • Dahlquist FW, Elwell RA, Lovely PS. Studies of bacterial chemotaxis in defined concentration gradients. A model for chemotaxis toward L-serine. J Supramol Struct. 1976;4(3):329–342. [PubMed]
  • Mesibov R, Ordal GW, Adler J. The range of attractant concentrations for bacterial chemotaxis and the threshold and size of response over this range. Weber law and related phenomena. J Gen Physiol. 1973 Aug;62(2):203–223. [PMC free article] [PubMed]
  • Adler J. A method for measuring chemotaxis and use of the method to determine optimum conditions for chemotaxis by Escherichia coli. J Gen Microbiol. 1973 Jan;74(1):77–91. [PubMed]
  • Mato JM, Losada A, Nanjundiah V, Konijn TM. Signal input for a chemotactic response in the cellular slime mold Dictyostelium discoideum. Proc Natl Acad Sci U S A. 1975 Dec;72(12):4991–4993. [PMC free article] [PubMed]

Articles from Biophysical Journal are provided here courtesy of The Biophysical Society

Formats:

Related citations in PubMed

See reviews...See all...

Cited by other articles in PMC

See all...

Links

Recent Activity

Your browsing activity is empty.

Activity recording is turned off.

Turn recording back on

See more...