2010/02/20 by Thierry Mora, Ned S. Wingreen · 2 citations
Biochemistry, Genetics and Molecular Biology · #q-bio.MN #q-bio.SC
paper · pdf · doi:10.1103/physrevlett.104.248101
published as Phys. Rev. Lett. 104, 248101 (2010) · 11 pages, 2 figures
arxiv created 2010/02/20 · arxiv updated 2011/11/28
Berg and Purcell [Biophys. J. 20, 193 (1977)] calculated how the accuracy of concentration sensing by single-celled organisms is limited by noise from the small number of counted molecules. Here we generalize their results to the sensing of concentration ramps, which is often the biologically relevant situation (e.g. during bacterial chemotaxis). We calculate lower bounds on the uncertainty of ramp sensing by three measurement devices: a single receptor, an absorbing sphere, and a monitoring sphere. We contrast two strategies, simple linear regression of the input signal versus maximum likelihood estimation, and show that the latter can be twice as accurate as the former. Finally, we consider biological implementations of these two strategies, and identify possible signatures that maximum likelihood estimation is implemented by real biological systems.