10.1021/acs.est.7b00590.s001
Zeyou Chen
Zeyou
Chen
Wei Zhang
Wei
Zhang
Gang Wang
Gang
Wang
Yingjie Zhang
Yingjie
Zhang
Yanzheng Gao
Yanzheng
Gao
Stephen A. Boyd
Stephen A.
Boyd
Brian J. Teppen
Brian J.
Teppen
James M. Tiedje
James M.
Tiedje
Dongqiang Zhu
Dongqiang
Zhu
Hui Li
Hui
Li
Bioavailability
of Soil-Sorbed Tetracycline to <i>Escherichia coli</i> under
Unsaturated Conditions
American Chemical Society
2017
matric water potentials
Oshtemo loamy sand
Webster clay loam
model simulation
agar diffusion assay
tetracycline uptake
coli cells
Escherichia coli bioreporter
soil-sorbed tetracycline
soil pore water
soil water
2017-05-19 16:18:40
Journal contribution
https://acs.figshare.com/articles/journal_contribution/Bioavailability_of_Soil-Sorbed_Tetracycline_to_i_Escherichia_coli_i_under_Unsaturated_Conditions/5024969
Increasing
concentrations of anthropogenic antibiotics in soils
are partly responsible for the proliferation of bacterial antibiotic
resistance. However, little is known about how soil-sorbed antibiotics
exert selective pressure on bacteria in unsaturated soils. This study
investigated the bioavailability of tetracycline sorbed on three soils
(Webster clay loam, Capac sandy clay loam, and Oshtemo loamy sand)
to a fluorescent <i>Escherichia coli</i> bioreporter under
unsaturated conditions using agar diffusion assay, microscopic visualization,
and model simulation. Tetracycline sorbed on the soils could be desorbed
and become bioavailable to the <i>E. coli</i> cells at matric
water potentials of −2.95 to −13.75 kPa. Bright fluorescent
rings were formed around the tetracycline-loaded soils on the unsaturated
agar surfaces, likely due to radial diffusion of tetracycline desorbed
from the soils, tetracycline uptake by the <i>E. coli</i> cells, and its inhibition on <i>E. coli</i> growth, which
was supported by the model simulation. The bioavailability of soil-sorbed
tetracycline was much higher for the Oshtemo soil, probably due to
faster diffusion of tetracycline in coarse-textured soils. Decreased
bioavailability of soil-sorbed tetracycline at lower soil water potential
likely resulted from reduced tetracycline diffusion in soil pore water
at smaller matric potential and/or suppressed tetracycline uptake
by <i>E. coli</i> at lower osmotic potential. Therefore,
soil-sorbed tetracycline could still exert selective pressure on the
exposed bacteria, which was influenced by soil physical processes
controlled by soil texture and soil water potential.