Iodine transfers in the coastal marine environment: the key role of brown algae and of their vanadium-dependent haloperoxidases.
Brown algal kelp species are the most efficient iodine accumulators among all living systems, with an average content of 1.0% of dry weight in Laminaria digitata, representing a ca. 30,000-fold accumulation of this element from seawater. Like other marine macroalgae, kelps are known to emit volatile short-lived organo-iodines, and molecular iodine which are believed to be a main vector of the iodine biogeochemical cycle as well as having a significant impact on atmospheric chemistry. Therefore, radioactive iodine can potentially accumulate in seaweeds and can participate in the biogeochemical cycling of iodine, thereby impacting human health. From a radioecological viewpoint, iodine-129 (129I, half-life of 1.6 x 10(7) years) is one of the most persistent radionuclide released from nuclear facilities into the environment. In this context, the speciation of iodine by seaweeds is of special importance and there is a need to further understand the mechanisms of iodine uptake and emission by kelps. Recent results on the physiological role and biochemistry of the vanadium haloperoxidases of brown algae emphasize the importance of these enzymes in the control of these processes.
Leblanc
Catherine
C
Centre national de la recherche scientifique, université Pierre et Marie Curie-Paris-VI, laboratoire international Associé-Dispersal and Adaptation in Marine Species, unité mixte de recherche 7139, 29682 Roscoff cedex, France. leblanc@sb-roscoff.fr
Colin
Carole
C
Cosse
Audrey
A
Delage
Ludovic
L
La Barre
Stéphane
S
Morin
Pascal
P
Fiévet
Bruno
B
Voiseux
Claire
C
Ambroise
Yves
Y
Verhaeghe
Elodie
E
Amouroux
David
D
Donard
Olivier
O
Tessier
Emmanuel
E
Potin
Philippe
P
D001692:Biological Transport; D007455:Iodine / Q000378:metabolism*; D008954:Models, Biological; D010544:Peroxidases / Q000378:metabolism*; D000459:Phaeophyceae / Q000187:drug effects / Q000201:enzymology*; D012623:Seawater; D012624:Seaweed / Q000201:enzymology; D013379:Substrate Specificity; D014639:Vanadium / Q000494:pharmacology*
D014639:Vanadium; D007455:Iodine; D010544:Peroxidases