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Titolo:
Copper uptake kinetics across the gills of rainbow trout (Oncorhynchus mykiss) measured using an improved isolated perfused head technique
Autore:
Campbell, HA; Handy, RD; Nimmo, M;
Indirizzi:
Univ Plymouth, Plymouth Environm Res Ctr, Plymouth PL4 8AA, Devon, EnglandUniv Plymouth Plymouth Devon England PL4 8AA outh PL4 8AA, Devon, England
Titolo Testata:
AQUATIC TOXICOLOGY
fascicolo: 3-4, volume: 46, anno: 1999,
pagine: 177 - 190
SICI:
0166-445X(199908)46:3-4<177:CUKATG>2.0.ZU;2-D
Fonte:
ISI
Lingua:
ENG
Soggetto:
SALMO-GAIRDNERI; MEMBRANE-VESICLES; ZINC INFLUX; CADMIUM; WATER; CHEMISTRY; TRANSPORT; TOXICITY; CU; METABOLISM;
Keywords:
rainbow trout (Oncorhynchus mykiss); Cu transport; Cu ATPase; perfused gill; Cu uptake kinetics;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Agriculture,Biology & Environmental Sciences
Citazioni:
46
Recensione:
Indirizzi per estratti:
Indirizzo: Campbell, HA Univ Plymouth, Plymouth Environm Res Ctr, Drake Circus, Plymouth PL4 8AA, Devon, England Univ Plymouth Drake Circus Plymouth Devon England PL4 8AA and
Citazione:
H.A. Campbell et al., "Copper uptake kinetics across the gills of rainbow trout (Oncorhynchus mykiss) measured using an improved isolated perfused head technique", AQUAT TOX, 46(3-4), 1999, pp. 177-190

Abstract

Measurements of branchial Cu uptake in vivo are complicated by rapid changes in the Cu stores of other body compartments such as the blood and liver. This study eliminates these problems by adopting an in vitro approach. Theperfused head technique was improved and viability extended to 2 h or more; so that kinetic studies on CLI uptake could be performed. The improvements included the use of Leibovitz L-15 culture medium instead of saline perfusates, ventilation of the gills with single pass flowing water to allow control of metal speciation, and the use of surgical glue rather than sutures to greatly reduce surgery time. Viability was assessed by perfusion pressure of < 50 cm H2O, demonstration of net Na influx, < 7.1 IU ml(-1) of lactate dehydrogenase (LDH) activity in the perfusate, and a steady-state ethanolpermeability of the gills to indicate the;absence of changes in functionalgill area. Gill morphology was also checked histologically. Concentrationsof Cu > 10 mu mol l(-1) caused only slight effects on some secondary lamellae, but this did not effect gill haemodynamics, gill permeability (ethanoluptake), or perfusate LDH activity when compared to similar measurements in non-viable preparations. Cumulative Cu uptake into the perfusate did not follow changes in perfusate flow and reached a steady state in about 1 h. Copper uptake kinetics based on the total Ca concentration in the water fitted a rectangular hyperbole (the Michaelis equation) with a regression coefficient (r(2)) of 0.98. The K-m and V-max values were 11.85 +/- 2.8 mu mol l(-1) and 52.2 +/- 4.9 nmol kg(-1) h(-1), respectively (mean +/- SE, n = 5). Copper uptake rate plotted against free divalent Cu (Cu2+) in the water did not fit the Michaelis equation, but showed second order reaction kinetics(r(2) = 0.87) with a rate Constant (k) of 4.43. Copper uptake was abolished by the serosal application of 50 mu mol l(-1) vanadate. These observations suggest that Cu uptake by the gills is mediated through a vanadate sensitive P-type ATPase which has a similar K-m (total Cu) to the mammalian Cu-ATPase. The second order reaction kinetics for Cu2+ uptake from the water is consistent with the reduction of Cu2+ to Cu+ prior to membrane transport, as observed in mammalian cells. (C) 1999 Elsevier Science B.V. All rights reserved.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 02/12/20 alle ore 15:32:41