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Uptake and efflux of 64 Cu by the marine cyanobacterium Synechococcus (WH7803)
Author(s) -
Croot Peter L.,
Bengt Karlson,
van Elteren J. T.,
Kroon J. J.
Publication year - 2003
Publication title -
limnology and oceanography
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.7
H-Index - 197
eISSN - 1939-5590
pISSN - 0024-3590
DOI - 10.4319/lo.2003.48.1.0179
Subject(s) - efflux , seawater , copper , kinetics , michaelis–menten kinetics , chemistry , synechococcus , saturation (graph theory) , nuclear chemistry , reaction rate constant , strain (injury) , biochemistry , biology , cyanobacteria , bacteria , enzyme , ecology , physics , genetics , mathematics , organic chemistry , quantum mechanics , combinatorics , enzyme assay , anatomy
The uptake and efflux of 64 Cu was studied in the marine cyanobacterium Synechoccous strain WH7803 (DC2). Uptake followed classical Michaelis∐Menten type kinetics in metal∐buffered seawater. The maximum uptake rate, V max , was 0.236 ± 0.016 × 10 −18 mol Cu cell −1 h −1 , with the half∐saturation constant, K S , of 10 −10.81±0.11 mol L −1 . An efflux mechanism was also observed in WH7803, whose growth was inhibited by high internal Cu concentrations. Efflux of Cu enabled WH7803 to maintain homeostasis for Cu at typical seawater ambient free copper concentrations ([Cu ] f ). The sensitivity of WH7803 growth to Cu was related to a simple inability to regulate internal Cu concentrations when external concentrations were >10 −11 mol L −1 .