Okadaic acid inhibits cell growth and photosynthetic electron transport in the alga Dunaliella tertiolecta

François Perreault, Marcelo Seleme Matias, Abdallah Oukarroum, William Gerson Matias, Radovan Popovic

Research output: Contribution to journalArticle

11 Scopus citations

Abstract

Okadaic acid (OA), which is produced by several dinoflagellate species, is a phycotoxin known to induce a decrease of biomass production in phytoplankton. However, the mechanisms of OA cytotoxicity are still unknown in microalgae. In this study, we exposed the green microalga Dunaliella tertiolecta to OA concentrations of 0.05 to 0.5μM in order to evaluate its effects on cell division, reactive oxygen species production and photosynthetic electron transport. After 72. h of treatment under continuous illumination, OA concentrations higher than 0.10μM decreased culture cell density, induced oxidative stress and inhibited photosystem II electron transport capacity. OA effect in D. tertiolecta was strongly light dependent since no oxidative stress was observed when D. tertiolecta was exposed to OA in the dark. In the absence of light, the effect of OA on culture cell density and photosystem II activity was also significantly reduced. Therefore, light appears to have a significant role in the toxicity of OA in microalgae. Our results indicate that the site of OA interaction on photosynthetic electron transport is likely to be at the level of the plastoquinone pool, which can lead to photo-oxidative stress when light absorbed by the light-harvesting complex of photosystem II cannot be dissipated via photochemical pathways. These findings allowed for a better understanding of the mechanisms of OA toxicity in microalgae.

Original languageEnglish (US)
Pages (from-to)198-204
Number of pages7
JournalScience of the Total Environment
Volume414
DOIs
StatePublished - Jan 1 2012
Externally publishedYes

Keywords

  • Cell growth
  • Dunaliella tertiolecta
  • Okadaic acid
  • Oxidative stress
  • Photosystem II
  • Phycotoxin

ASJC Scopus subject areas

  • Environmental Engineering
  • Environmental Chemistry
  • Waste Management and Disposal
  • Pollution

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