title: Different responses of the marine diatom Phaeodactylum tricornutum to copper toxicity.
abstract: Different responses of the marine diatom Phaeodactylum tricornutum (Bohlin) to toxic copper concentrations were investigated. Besides the classical variables applied to toxicity studies in microalgae, such as growth or chlorophyll a content, other variables analyzed by flow cytometry were used. Toxic effects due to copper concentration were observed. Cell density reached in the stationary phase was reduced to 50% in cultures with 20 mg Cu/l, with respect to control cultures without copper. Cell light scatter properties (related to cell volume and intracellular granularity) and chlorophyll a fluorescence of microalgal cells were determined by flow cytometry analysis at the beginning of growth, 1 h after copper exposure, and when cultures reached the stationary phase (72 h). After 1 h of exposure to metal, no differences were observed, but when cultures reached the stationary phase, a gradual increase in the variables analyzed by flow cytometry was observed as the copper concentration increased. The increase in chlorophyll a fluorescence detected by flow cytometry was not correlated with an increase in the cell content of this photopigment, thus indicating an inhibitory effect of copper on photosystem II.
authors.affiliation: Laboratorio de Microbiología, Facultad de Ciencias, Universidad de La Coruña.
authors.forename: S
authors.initials: S
authors.lastname: Reiriz
authors.forename: A
authors.initials: A
authors.lastname: Cid
authors.forename: E
authors.initials: E
authors.lastname: Torres
authors.forename: J
authors.initials: J
authors.lastname: Abalde
authors.forename: C
authors.initials: C
authors.lastname: Herrero
mesh_terms: D002734:Chlorophyll / Q000032:analysis; D000077194:Chlorophyll A; D003300:Copper / Q000633:toxicity*; D017377:Diatoms / Q000737:chemistry / Q000187:drug effects* / Q000254:growth & development; D004305:Dose-Response Relationship, Drug; D045342:Light-Harvesting Protein Complexes; D045322:Photosynthetic Reaction Center Complex Proteins / Q000187:drug effects; D045332:Photosystem II Protein Complex
chemical_list: D045342:Light-Harvesting Protein Complexes; D045322:Photosynthetic Reaction Center Complex Proteins; D045332:Photosystem II Protein Complex; D002734:Chlorophyll; D003300:Copper; D000077194:Chlorophyll A