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Title: Importance of passive diffusion in the uptake of polychlorinated biphenyls by phagotrophic protozoa

Abstract

Unicellular protozoan grazers represent a size class of organisms where a transition in the mechanism of chlorobiphenyl (CB) introduction, from diffusion through surface membranes to ingestion of contaminated prey, could occur. This study compares the relative importance of these two processes in the overall uptake of polychlorinated biphenyls by protists. Uptake rates and steady-state concentrations were compared in laboratory cultures of grazing and nongrazing protozoa. These experiments were conducted with a 10-{micro}m marine scuticociliate (Uronema sp.), bacterial prey (Halomonas halodurans), and a suite of 21 CB congeners spanning a range of aqueous solubilities. The dominant pathway of CB uptake by both grazing and nongrazing protozoa was diffusion. Organic-carbon-normalized CB concentrations (in the protozoan cell) were equivalent in grazing and nongrazing protozoa for all congeners studied. Rate constants for uptake into and loss from the protozoan cell were independently determined by using [3,3{prime}, 4,4{prime}-{sup 14}C]tetrachlorobiphenyl (IUPAC no. 77), 0.38 {+-} 0.03 min{sup {minus}1} and (1.1 {+-} 0.1) x 10{sup {minus}5} (g of organic carbon){minus}{sup {minus}1} min{sup {minus}1}, respectively. Magnitudes of the uptake and loss processes were calculated and compared by using a numerical model. The model result was consistent with data from the bioaccumulation experiment and supported the hypothesis that diffusivemore » uptake is faster than ingestive uptake in phagotrophic unicellular protozoa.« less

Authors:
; ;
Publication Date:
Research Org.:
Massachusetts Inst. of Tech., Woods Hole Oceanographic Institution Joint Program in Oceanography, Woods Hole, MA (US)
OSTI Identifier:
20075760
Resource Type:
Journal Article
Journal Name:
Applied and Environmental Microbiology
Additional Journal Information:
Journal Volume: 66; Journal Issue: 5; Other Information: PBD: May 2000; Journal ID: ISSN 0099-2240
Country of Publication:
United States
Language:
English
Subject:
54 ENVIRONMENTAL SCIENCES; 63 RADIATION, THERMAL, AND OTHER ENVIRONMENTAL POLLUTANT EFFECTS ON LIVING ORGANISMS AND BIOLOGICAL MATERIALS; POLYCHLORINATED BIPHENYLS; BIOLOGICAL ACCUMULATION; PROTOZOA; BIOLOGICAL INDICATORS; WATER POLLUTION

Citation Formats

Kujawinski, E.B., Farrington, J.W., and Moffett, J.W. Importance of passive diffusion in the uptake of polychlorinated biphenyls by phagotrophic protozoa. United States: N. p., 2000. Web. doi:10.1128/AEM.66.5.1987-1993.2000.
Kujawinski, E.B., Farrington, J.W., & Moffett, J.W. Importance of passive diffusion in the uptake of polychlorinated biphenyls by phagotrophic protozoa. United States. doi:10.1128/AEM.66.5.1987-1993.2000.
Kujawinski, E.B., Farrington, J.W., and Moffett, J.W. Mon . "Importance of passive diffusion in the uptake of polychlorinated biphenyls by phagotrophic protozoa". United States. doi:10.1128/AEM.66.5.1987-1993.2000.
@article{osti_20075760,
title = {Importance of passive diffusion in the uptake of polychlorinated biphenyls by phagotrophic protozoa},
author = {Kujawinski, E.B. and Farrington, J.W. and Moffett, J.W.},
abstractNote = {Unicellular protozoan grazers represent a size class of organisms where a transition in the mechanism of chlorobiphenyl (CB) introduction, from diffusion through surface membranes to ingestion of contaminated prey, could occur. This study compares the relative importance of these two processes in the overall uptake of polychlorinated biphenyls by protists. Uptake rates and steady-state concentrations were compared in laboratory cultures of grazing and nongrazing protozoa. These experiments were conducted with a 10-{micro}m marine scuticociliate (Uronema sp.), bacterial prey (Halomonas halodurans), and a suite of 21 CB congeners spanning a range of aqueous solubilities. The dominant pathway of CB uptake by both grazing and nongrazing protozoa was diffusion. Organic-carbon-normalized CB concentrations (in the protozoan cell) were equivalent in grazing and nongrazing protozoa for all congeners studied. Rate constants for uptake into and loss from the protozoan cell were independently determined by using [3,3{prime}, 4,4{prime}-{sup 14}C]tetrachlorobiphenyl (IUPAC no. 77), 0.38 {+-} 0.03 min{sup {minus}1} and (1.1 {+-} 0.1) x 10{sup {minus}5} (g of organic carbon){minus}{sup {minus}1} min{sup {minus}1}, respectively. Magnitudes of the uptake and loss processes were calculated and compared by using a numerical model. The model result was consistent with data from the bioaccumulation experiment and supported the hypothesis that diffusive uptake is faster than ingestive uptake in phagotrophic unicellular protozoa.},
doi = {10.1128/AEM.66.5.1987-1993.2000},
journal = {Applied and Environmental Microbiology},
issn = {0099-2240},
number = 5,
volume = 66,
place = {United States},
year = {2000},
month = {5}
}