TY - JOUR
T1 - Phytochelatin production by marine phytoplankton at low free metal ion concentrations
T2 - Laboratory studies and field data from Massachusetts Bay
AU - Ahner, Beth A.
AU - Price, Neil M.
AU - Morel, Francois M. M.
PY - 1994/8/30
Y1 - 1994/8/30
N2 - Phytochelatins are small metal-binding polypeptides synthesized by algae in response to high metal concentrations. Using a very sensitive HPLC method, we have quantified phytochelatins from phytoplankton in laboratory cultures at environmentally relevant metal concentrations and in marine field samples. Intracellular concentrations of phytochelatin, in the diatom Thalassiosira weissflogii, exhibit a distinct dose-response relation with free Cd2+ concentration in the medium-not with total Cd2+- and are detectable even when the free Cd2+ concentration is less than 1 pM. In Massachusetts Bay, phytochelatin levels (normalized to chlorophyll a) in the particulate fraction are similar to those measured in laboratory cultures exposed to picomolar free Cd2+ concentrations and exhibit a decreasing seaward trend. Incubations of natural samples with added Cd2+ confirmed the induction of the peptides by this metal. Ambient phytochelatin concentrations thus appear to provide a measure of the metal stress resulting from the complex mixture of trace metals and chelators in natural waters.
AB - Phytochelatins are small metal-binding polypeptides synthesized by algae in response to high metal concentrations. Using a very sensitive HPLC method, we have quantified phytochelatins from phytoplankton in laboratory cultures at environmentally relevant metal concentrations and in marine field samples. Intracellular concentrations of phytochelatin, in the diatom Thalassiosira weissflogii, exhibit a distinct dose-response relation with free Cd2+ concentration in the medium-not with total Cd2+- and are detectable even when the free Cd2+ concentration is less than 1 pM. In Massachusetts Bay, phytochelatin levels (normalized to chlorophyll a) in the particulate fraction are similar to those measured in laboratory cultures exposed to picomolar free Cd2+ concentrations and exhibit a decreasing seaward trend. Incubations of natural samples with added Cd2+ confirmed the induction of the peptides by this metal. Ambient phytochelatin concentrations thus appear to provide a measure of the metal stress resulting from the complex mixture of trace metals and chelators in natural waters.
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U2 - 10.1073/pnas.91.18.8433
DO - 10.1073/pnas.91.18.8433
M3 - Article
C2 - 8078899
AN - SCOPUS:0027936221
SN - 0027-8424
VL - 91
SP - 8433
EP - 8436
JO - Proceedings of the National Academy of Sciences of the United States of America
JF - Proceedings of the National Academy of Sciences of the United States of America
IS - 18
ER -