Chemotactic Sensitivity of Escherichia coli to Diffusion Perturbations in Narrow Tubes

Pratap R. Patnaik*
Institute of Microbial Technology, Sector 39-A, Chandigarh-160 036, India

© 2008 Patnaik et al.

open-access license: This is an open access article distributed under the terms of the Creative Commons Attribution 4.0 International Public License (CC-BY 4.0), a copy of which is available at: This license permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.

* Address correspondence to this author at the Institute of Microbial Technology, Sector 39-A, Chandigarh-160 036, India; Fax: +91-172-2690132/585/632; E-mail:


Diffusion resistance hinders the free chemotactic motility of bacteria through narrow tubes and capillaries. In many such situations, diffusion is significant and often subject to environmental perturbations. This problem has been analyzed through the sensitivities of Escherichia coli cells, a secreted chemoattractant (aspartase) and a nutrient. Differences and similarities among the sensitivity profiles with respect to the three diffusion coefficients reveal useful information about interactions between diffusion and chemotaxis. The results are consistent with the concept of stabilization created by negative feedback, either within the chemosensory network or from outside. Their implications for some real systems are discussed.

Keywords: Bacterial chemotaxis, diffusion, narrow tubes, interactions, feedback stabilization.