molecular evidence of the toxic effects of diatom diets on gene expression patterns in copepods毒性作用的分子证据硅藻饮食在桡足类的基因表达模式.pdfVIP

Molecular Evidence of the Toxic Effects of Diatom Diets on Gene Expression Patterns in Copepods Chiara Lauritano*, Marco Borra, Ylenia Carotenuto, Elio Biffali, Antonio Miralto, Gabriele Procaccini, Adrianna Ianora Stazione Zoologica Anton Dohrn, Napoli, Italy Abstract Background: Diatoms are dominant photosynthetic organisms in the world’s oceans and are considered essential in the transfer of energy through marine food chains. However, these unicellular plants at times produce secondary metabolites such as polyunsaturated aldehydes and other products deriving from the oxidation of fatty acids that are collectively termed oxylipins. These cytotoxic compounds are responsible for growth inhibition and teratogenic activity, potentially sabotaging future generations of grazers by inducing poor recruitment in marine organisms such as crustacean copepods. Principal Findings: Here we show that two days of feeding on a strong oxylipin-producing diatom (Skeletonema marinoi) is sufficient to inhibit a series of genes involved in aldehyde detoxification, apoptosis, cytoskeleton structure and stress response in the copepod Calanus helgolandicus. Of the 18 transcripts analyzed by RT-qPCR at least 50% were strongly down- regulated (aldehyde dehydrogenase 9, 8 and 6, cellular apoptosis susceptibility and inhibitor of apoptosis IAP proteins, heat shock protein 40, alpha- and beta-tubulins) compared to animals fed on a weak oxylipin-producing diet (Chaetoceros socialis) which showed no changes in gene expression profiles. Conclusions: Our results provide molecular evidence of the toxic effects of strong oxylipin-producing diatoms on grazers, showing that primary defense systems that should be activated to protect copepods against toxic algae can be inhibited. On the other hand other classical detoxification gene