Mediterranean Mussel Gene Expression Profile Induced by Okadaic Acid Exposure

Abstract

Seasonal seawater temperature increases define optimal growth conditions for Dinoflagellate species which can reach high concentrations in water column and also in filter-feeding organisms like Mytilus galloprovincialis. Commonly produced by Dinophysis and Prorocentrum spp., okadaic acid (OA) and its analogues are responsible for the Diarrheic Shellfish Poisoning (DSP) syndrome in humans. Closure of shellfishing grounds is therefore recommended by the EU when DSP toxin levels in shellfish exceed 16 μg OA 100 g(-1) flesh. Despite not being responsible for casualties either in humans or mussels, DSP outbreaks are considered natural events causing health and economic issues due to the frequency of their occurrence. Since gene expression studies offer a wide range of different solutions, we used a mussel cDNA microarray to evaluate gene expression changes in the digestive gland of mussels fed for five weeks with OA-contaminated nutrient. Among the differentially expressed genes we observed a general up-regulation of transcripts coding for stress proteins, proteins involved in cellular synthesis, and a few not annotated proteins. Overall, at the first time point analyzed we identified 58 candidate transcripts for OA-induced stress in mussels, half of which have unknown function. In this paper we present the first gene expression analysis performed on Mediterranean mussels exposed to okadaic acid. The characterization of these transcripts could be useful for the identification of an early physiological response to OA exposure.

Proteomic profile in Perna viridis after exposed to Prorocentrum lima, a dinoflagellate producing DSP toxins

“…In the current study, the expression of ubiquitin-conjugating enzyme E2 and SINA-like protein were all up-regulated in mussel after exposure to P. lima, suggesting that P. lima and associated DSP toxins induced ubiquitination/proteasome activity, which might give a possible explanation of the degeneration of the digestive cells after OA exposure in previous reports (Auriemma and Battistella, 2004;Wang et al, 2012). Consistent with our observation, using cDNA microarray, Manfrin et al (2010) found a series of mRNAs involved in proteasome activity were overexpressed such as a partial mRNA for ubiquitin C-variant with an ubiquitin-domain and a polyubiquitin in the digestive gland of mussels after OA exposure.…”

“…Actually, OA-induced changes in cytoskeletal architecture and cellecell contact have been extensively reported (Leira et al, 2001;Espiña and Rubiolo, 2008;Vale and Botana, 2008;Vilariño et al, 2008;Espiña et al, 2010;Wang et al, 2011;Hanana et al, 2012;Huang et al, 2013;Opsahl et al, 2013). Using a mussel cDNA microarray, Manfrin et al (2010) found that 9% of up-regulated transcripts in mussel induced by OA exposure were potentially involved in cytoskeleton organization. Hanana et al (2012) observed that the exposure of clam heart to OA at 1 mM for 24 h could induce disorganization of the actin cytoskeleton, rounding and detachment of the fibroblastic cells.…”

“…Quite few studies have conducted the molecular effects of OA, and the information currently available is woefully insufficient due to the still limited genetic knowledge of the bivalves (Malagoli et al, 2008;Fl orez-Barr os et al, 2011;Manfrin et al, 2012;Prado-Alvarez et al, 2012;Prego-Faraldo et al, 2013). Manfrin et al (2010) for the first time identified several candidate transcripts in Mediterranean mussel (Mytilus galloprovincialis) as OA-stress markers over 35 days of exposure by cDNA microarray. Romero-Geraldo and Hern andez-Saavedra (2012) observed noticeable differences in genes expression in juvenile oysters at 14 days after exposure to P. lima.…”

Effects of In Vitro Exposure to Diarrheic Toxin Producer Prorocentrum lima on Gene Expressions Related to Cell Cycle Regulation and Immune Response in Crassostrea gigas

“…Currently, a mussel cDNA digestive gland microarray fed for five weeks with OA contaminated nutrient reported a general up-regulation of transcripts coding for stress proteins and those involved in cellular synthesis [33]. The Pacific oyster C. gigas is a suspension-feeding bivalve mollusk, of great interest as a study model given its ecological, economic, public health, and genomic relevance because it has a completely sequenced genome [34], [35].…”

Massively Parallel Amplicon Sequencing Reveals Isotype-Specific Variability of Antimicrobial Peptide Transcripts in Mytilus galloprovincialis

“…Also gene-centered studies take advantage of the massive production of ESTs which currently contributes to the identification of molecules and pathways underlying the mussel response to various natural and experimental conditions [45]–[48]. Among the 67,726 ESTs and 4680 aminoacid sequences publicly available for the Mytilus genus, about 29 and 32%, respectively, refer to M. galloprovincialis (www.ncbi.nlm.nih.gov, June 2011).…”