Gene Regulation in the Marine Diatom Thalassiosira pseudonana upon Exposure to Polycyclic Aromatic Hydrocarbons (PAHs)

Diatoms are eukaryotic algae, which can be found worldwide in oceans and freshwaters. These organisms are ecologically relevant due to their key role in the global carbon cycle. It is thought that they contribute about 25% to the global primary production (Falciatore, et al, Annu Rev Plant Biol 2002; 53: 109-130). Furthermore the full genome sequence of Thalassosira pseudonana (Armbrust et al, Science 2004; 306: 79-86) envisaged the possibility to use this organism in ecotoxicology to study the effects of pollutants at molecular level and to develop molecular indicators to monitor the ecological quality of water. For this purpose, we investigated the effects of three polycyclic aromatic hydrocarbons (PAHs¸ pyrene, fluoranthene, and benzo[a]pyrene), either as single compound or as mixture, at molecular level. Dose-response curves for growth inhibition were determined and four concentrations eliciting from “no effect” up to a severe growth inhibition were chosen for further investigation to detect alterations at gene expression level by Real-Time PCR. Among the eight selected genes, two were strongly influenced by the PAH treatment. lacsA, which is involved in the fatty acid metabolism, was found to be strongly up-regulated by all single PAHs, as well as by the mixture. sil3, involved in the formation of the silica shell, was repressed by a factor up to three even at low PAH concentrations not eliciting any growth inhibition. For other genes, involved e.g. in photosynthesis, a slight down-regulation was detected. Based on the effects at gene expression level it can be assumed that PAHs impair the fatty acid metabolism and silica shell formation.

BOPP Stephanie;  LETTIERI Teresa; 

2007-07-11

ELSEVIER SCIENCE BV

JRC35481

https://publications.jrc.ec.europa.eu/repository/handle/JRC35481,