Measurement of bacterial random motility and chemotaxis coefficients: I. Stopped-flow diffusion chamber assay Export

@article{1991aFord, abstract = {Bacterial chemotaxis, the directed movement of a cell population in response to a chemical gradient, plays a critical role in the distribution and dynamic interaction of bacterial populations in nonmixed systems. Therefore, in order to make reliable predictions about the migratory behavior of bacteria within the environment, a quantitative characterization of the chemotactic response in terms of intrinsic cell properties is needed.The design of the stopped-flow diffusion chamber (SFDC) provides a well-characterized chemical gradient and reliable method for measuring bacterial migration behavior. During flow through the chamber, a step change in chemical concentration is imposed on a uniform suspension of bacteria. Once flow is stopped, diffusion causes a transient chemical gradient to develop, and bacteria respond by forming a band of high cell density which travels toward higher concentrations of the attractant. Changes in bacterial spatial distributions observed through light scattering are recorded on photomicrographs during a 10-min period. Computer-aided image analysis converts absorbance of the photographic negatives to a digital representation of bacterial density profiles. A mathematical model (part II) is used to quantitatively characterize these observations in terms of intrinsic cell parameters: a chemotactic sensitivity coefficient, mu0, from the aggregate cell density accumulated in the band and a random motility coefficient, mu, from population dispersion in the absence of a chemical gradient.Using the SFDC assay and an individual-cell-based mathematical model, we successfully determined values for both of these population parameters for Escherichia coli K12 responding to fucose. The values obtained were mu = 1.1 ± 0. 4 × 10-5 cm2/s and chio = 8 ± 3 ± 10-5 cm2/s. We have demonstrated a method capable of determining these parameter values from the now validated mathematical model which will be useful for predicting bacterial migration in application systems.}, address = {Department of Chemical Engineering, University of Pennsylvania, Philadelphia, Pennsylvania 19104}, author = {Ford, Roseanne M. and Phillips, Bret R. and Quinn, John A. and Lauffenburger, Douglas A.}, citeulike-article-id = {4386068}, citeulike-linkout-0 = {http://dx.doi.org/10.1002/bit.260370707}, citeulike-linkout-1 = {http://view.ncbi.nlm.nih.gov/pubmed/18600656}, citeulike-linkout-2 = {http://www.hubmed.org/display.cgi?uids=18600656}, citeulike-linkout-3 = {http://www3.interscience.wiley.com/cgi-bin/abstract/107622945/ABSTRACT}, day = {25}, doi = {10.1002/bit.260370707}, issn = {0006-3592}, journal = {Biotechnology and Bioengineering}, keywords = {chamber, chemotaxis, stopped-flow}, month = {March}, number = {7}, pages = {647--660}, posted-at = {2009-04-23 13:33:59}, priority = {2}, title = {Measurement of bacterial random motility and chemotaxis coefficients: I. Stopped-flow diffusion chamber assay}, url = {http://dx.doi.org/10.1002/bit.260370707}, volume = {37}, year = {1991} }

TY - JOUR ID - 1991aFord L3 - citeulike-article-id:4386068 N2 - Bacterial chemotaxis, the directed movement of a cell population in response to a chemical gradient, plays a critical role in the distribution and dynamic interaction of bacterial populations in nonmixed systems. Therefore, in order to make reliable predictions about the migratory behavior of bacteria within the environment, a quantitative characterization of the chemotactic response in terms of intrinsic cell properties is needed.The design of the stopped-flow diffusion chamber (SFDC) provides a well-characterized chemical gradient and reliable method for measuring bacterial migration behavior. During flow through the chamber, a step change in chemical concentration is imposed on a uniform suspension of bacteria. Once flow is stopped, diffusion causes a transient chemical gradient to develop, and bacteria respond by forming a band of high cell density which travels toward higher concentrations of the attractant. Changes in bacterial spatial distributions observed through light scattering are recorded on photomicrographs during a 10-min period. Computer-aided image analysis converts absorbance of the photographic negatives to a digital representation of bacterial density profiles. A mathematical model (part II) is used to quantitatively characterize these observations in terms of intrinsic cell parameters: a chemotactic sensitivity coefficient, mu0, from the aggregate cell density accumulated in the band and a random motility coefficient, mu, from population dispersion in the absence of a chemical gradient.Using the SFDC assay and an individual-cell-based mathematical model, we successfully determined values for both of these population parameters for Escherichia coli K12 responding to fucose. The values obtained were mu = 1.1 ± 0. 4 × 10-5 cm2/s and chio = 8 ± 3 ± 10-5 cm2/s. We have demonstrated a method capable of determining these parameter values from the now validated mathematical model which will be useful for predicting bacterial migration in application systems. IS - 7 JF - Biotechnology and Bioengineering SN - 0006-3592 AD - Department of Chemical Engineering, University of Pennsylvania, Philadelphia, Pennsylvania 19104 EP - 660 TI - Measurement of bacterial random motility and chemotaxis coefficients: I. Stopped-flow diffusion chamber assay VL - 37 SP - 647 KW - chamber KW - chemotaxis KW - stopped-flow AU - Ford, Roseanne AU - Phillips, Bret AU - Quinn, John AU - Lauffenburger, Douglas PY - 1991/03/25/ UR - http://dx.doi.org/10.1002/bit.260370707 ER -