Uptake of 2,4-dichlorophenoxyacetic acid by Pseudomonas fluorescens

Applied and Environmental Microbiology



Factors influencing the uptake of the sodium salt of 2,4-dichlorophenoxyacetic acid (2,4-D), under conditions in which no net metabolism occurred, were investigated in an effort to determine both the significance of “non-metabolic” uptake as a potential agent in reducing pesticide levels and the mechanisms involved. Uptake of 2,4-D was affected by pH, temperature, and the presence of other organic and inorganic compounds. Uptake was more pronounced at pH values less than 6, which implies that there may be some interaction between charged groups on the cell and the ionized carboxyl group of 2,4-D. Active transport, carrier-mediated diffusion, passive diffusion, and adsorption were considered as possible mechanisms. Though uptake was inhibited by glucose, sodium azide, and fluorodinitrobenzene (but not by uranyl ion), 2,4-D was not accumulated against a concentration gradient, a necessary consequence of an active transport system, nor was isotope counterflow found to occur. Thus, carrier-mediated diffusion was finally precluded, implying that uptake probably occurs by a two-step process: sorption onto the cell wall followed by passive diffusion into the cytoplasm.

Publication type Article
Publication Subtype Journal Article
Title Uptake of 2,4-dichlorophenoxyacetic acid by Pseudomonas fluorescens
Series title Applied and Environmental Microbiology
Volume 14
Issue 4
Year Published 1966
Language English
Publisher American Society for Microbiology
Contributing office(s) Columbia Environmental Research Center
Description 5 p.
First page 486
Last page 491
Online Only (Y/N) N
Additional Online Files (Y/N) N
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