Transcriptional response after exposure to domoic acid-producing Pseudo-nitzschia in the digestive gland of the mussel Mytilus galloprovincialis

Toxicon ◽  
2017 ◽  
Vol 140 ◽  
pp. 60-71 ◽  
Author(s):  
Antonio J. Pazos ◽  
Pablo Ventoso ◽  
Roi Martínez-Escauriaza ◽  
M. Luz Pérez-Parallé ◽  
Juan Blanco ◽  
...  
Toxins ◽  
2021 ◽  
Vol 13 (7) ◽  
pp. 458
Author(s):  
Juan Blanco ◽  
Carmen Mariño ◽  
Helena Martín ◽  
Gonzalo Álvarez ◽  
Araceli E. Rossignoli

Cultures of the mussel Mytilus galloprovincialis are frequently affected by accumulation of the amnesic shellfish poisoning toxin domoic acid (DA). This species is characterized by a fast uptake and release of the toxin. In this work, the main characteristics of the uptake mechanism have been studied by incubation of digestive gland thin slices in media with different composition and DA concentration. DA uptake seems to follow Michaelis–Menten kinetics, with a very high estimated KM (1722 µg DA mL−1) and a Vmax of 71.9 µg DA g−1 h−1, which is similar to those found for other amino acids in invertebrates. Replacement of NaCl from the incubation media by Cl-choline (Na+-free medium) did not significantly reduce the uptake, but replacement by sorbitol (Na+-free and Cl−-depleted medium) did. A new experiment replacing all chlorides with their equivalent gluconates (Na+- and Cl−-free medium) showed an important reduction in the uptake that should be attributed to the absence of chloride, pointing to a Na+-independent, Cl− (or anion-) dependent transporter. In media with Na+ and Cl−, neither decreasing the pH nor adding cyanide (a metabolic inhibitor) had significant effect on DA uptake, suggesting that the transport mechanism is not H+- or ATP-dependent. In a chloride depleted medium, lowering pH or adding CN increased the uptake, suggesting that other anions could, at least partially, substitute chloride.


Toxins ◽  
2019 ◽  
Vol 11 (2) ◽  
pp. 97 ◽  
Author(s):  
Pablo Ventoso ◽  
Antonio J. Pazos ◽  
M. Luz Pérez-Parallé ◽  
Juan Blanco ◽  
Juan C. Triviño ◽  
...  

Some species of the genus Pseudo-nitzschia produce the toxin domoic acid, which causes amnesic shellfish poisoning (ASP). Given that bivalve mollusks are filter feeders, they can accumulate these toxins in their tissues. To elucidate the transcriptional response of the queen scallop Aequipecten opercularis after exposure to domoic acid-producing Pseudo-nitzschia, the digestive gland transcriptome was de novo assembled using an Illumina HiSeq 2000 platform. Then, a differential gene expression analysis was performed. After the assembly, 142,137 unigenes were obtained, and a total of 10,144 genes were differentially expressed in the groups exposed to the toxin. Functional enrichment analysis found that 374 Pfam (protein families database) domains were significantly enriched. The C1q domain, the C-type lectin, the major facilitator superfamily, the immunoglobulin domain, and the cytochrome P450 were among the most enriched Pfam domains. Protein network analysis showed a small number of highly connected nodes involved in specific functions: proteasome components, mitochondrial ribosomal proteins, protein translocases of mitochondrial membranes, cytochromes P450, and glutathione S-transferases. The results suggest that exposure to domoic acid-producing organisms causes oxidative stress and mitochondrial dysfunction. The transcriptional response counteracts these effects with the up-regulation of genes coding for some mitochondrial proteins, proteasome components, and antioxidant enzymes (glutathione S-transferases, thioredoxins, glutaredoxins, and copper/zinc superoxide dismutases).


Toxins ◽  
2021 ◽  
Vol 13 (5) ◽  
pp. 339
Author(s):  
Pablo Ventoso ◽  
Antonio J. Pazos ◽  
Juan Blanco ◽  
M. Luz Pérez-Parallé ◽  
Juan C. Triviño ◽  
...  

Some diatom species of the genus Pseudo-nitzschia produce the toxin domoic acid. The depuration rate of domoic acid in Pecten maximus is very low; for this reason, king scallops generally contain high levels of domoic acid in their tissues. A transcriptomic approach was used to identify the genes differentially expressed in the P. maximus digestive gland after the injection of domoic acid. The differential expression analysis found 535 differentially expressed genes (226 up-regulated and 309 down-regulated). Protein–protein interaction networks obtained with the up-regulated genes were enriched in gene ontology terms, such as vesicle-mediated transport, response to stress, signal transduction, immune system process, RNA metabolic process, and autophagy, while networks obtained with the down-regulated genes were enriched in gene ontology terms, such as response to stress, immune system process, ribosome biogenesis, signal transduction, and mRNA processing. Genes that code for cytochrome P450 enzymes, glutathione S-transferase theta-1, glutamine synthase, pyrroline-5-carboxylate reductase 2, and sodium- and chloride-dependent glycine transporter 1 were among the up-regulated genes. Therefore, a stress response at the level of gene expression, that could be caused by the domoic acid injection, was evidenced by the alteration of several biological, cellular, and molecular processes.


Author(s):  
Krzysztof Gwoździński ◽  
Marta Gonciarz ◽  
Ewa Kilańczyk ◽  
Aleksandra Kowalczyk ◽  
Anna Pieniążek ◽  
...  

Antioxidant enzyme activities and lipid peroxidation inIn the present work we have studied some of the indicators of oxidative damage of the digestive gland tissue of two populations of mussels


Toxins ◽  
2020 ◽  
Vol 12 (6) ◽  
pp. 371
Author(s):  
Juan Blanco ◽  
Aida Mauríz ◽  
Gonzalo Álvarez

The king scallop Pecten maximus retains the amnesic shellfish poisoning toxin, domoic acid (DA), for a long time. Most of the toxin is accumulated in the digestive gland, but this organ contains several cell types whose contribution to the accumulation of the toxin is unknown. Determining the time-course of the depuration by analyzing whole organs is difficult because the inter-individual variability is high. A sampling method, using biopsies of the digestive gland, has been developed. This method allows for repetitive sampling of the same scallop, but the representativeness of the samples obtained in this way needs to be validated. In this work, we found that the distribution of DA in the digestive gland of the scallops is mostly homogeneous. Only the area closest to the gonad, and especially its outer portion, had a lower concentration than the other ones, probably due to a transfer of the toxin to the intestinal loop. Samples obtained by biopsies can therefore be considered to be representative. Most of the toxin was accumulated in large cells (mostly digestive cells), which could be due to differences during the toxin absorption or to the preferential depuration of the toxin from the small cells (mostly secretory).


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