Biomaterial Database

Quantification of chemotaxis to naphthalene by Pseudomonas putida G7. 1999

R B Marx, and M D Aitken

Department of Environmental Sciences, School of Public Health, The University of North Carolina at Chapel Hill, North Carolina 27599-7400, USA. rmarx@email.unc.edu

The capillary assay was used to quantify the chemotactic response of Pseudomonas putida G7 to naphthalene. Experiments were conducted in which the cell concentration in the assay chamber, the naphthalene concentration in the capillary, or the incubation time was varied. Data from these experiments were evaluated with a model that accounted for the effect of diffusion on the distribution of substrate and the transport of cells from the chamber through the capillary orifice. By fitting a numerical solution of this model to the data, it was possible to determine the chemotactic sensitivity coefficient, chi0. The mean of the best-fit values for chi0 from the three types of experiments was 7.2 x 10(-5) cm2/s. A less computationally intensive model based on earlier approaches that ignore cell transport in the chamber resulted in chi0 values that were approximately three times higher. The models evaluated in the present study could simulate the results of capillary assays only at low chamber cell concentrations, for which the effect of consumption on the distribution of substrate was negligible. Results from this work suggest that it is possible to use the capillary assay to quantify taxis towards environmentally relevant chemoeffectors that have low aqueous solubility.

UI	MeSH Term	Description	Entries
D008954	Models, Biological	Theoretical representations that simulate the behavior or activity of biological processes or diseases. For disease models in living animals, DISEASE MODELS, ANIMAL is available. Biological models include the use of mathematical equations, computers, and other electronic equipment.	Biological Model,Biological Models,Model, Biological,Models, Biologic,Biologic Model,Biologic Models,Model, Biologic
D009281	Naphthalenes	Two-ring crystalline hydrocarbons isolated from coal tar. They are used as intermediates in chemical synthesis, as insect repellents, fungicides, lubricants, preservatives, and, formerly, as topical antiseptics.
D002633	Chemotaxis	The movement of cells or organisms toward or away from a substance in response to its concentration gradient.	Haptotaxis
D001673	Biodegradation, Environmental	Elimination of ENVIRONMENTAL POLLUTANTS; PESTICIDES and other waste using living organisms, usually involving intervention of environmental or sanitation engineers.	Bioremediation,Phytoremediation,Natural Attenuation, Pollution,Environmental Biodegradation,Pollution Natural Attenuation
D016958	Pseudomonas putida	A species of gram-negative, aerobic bacteria isolated from soil and water as well as clinical specimens. Occasionally it is an opportunistic pathogen.