Exposure effects to the harmful algal bloom (HAB)-dependent marine biotoxin domoic acid on the antioxidant network of the mussel Mytilus edulis platensis.

Perkinsus spp. are pathogenic protistan parasites that pose a significant threat to the aquaculture of the Hong Kong oyster (Crassostrea hongkongensis). This study investigated the transcriptional response of the Hong Kong oyster digestive gland to natural Perkinsus spp. infection. The parasite species was identified via PCR, while infection prevalence, tissue-specific abundance, and infection grade were assessed using Ray's Fluid Thioglycollate Medium (RFTM) culture. Transcriptomic analysis was performed to compare gene expression profiles among uninfected (Neg), lightly infected (L), and light-to-moderately infected (LM) oyster digestive glands. Results confirmed the presence of P. beihaiensis, with an overall infection prevalence of 85.5%. The digestive gland exhibited the highest infection prevalence (80.1%) and abundance (1880.0 ± 144.2 cells/g) compared to other tissues (gills, mantle, and siphon). Transcriptomic analysis of 12 samples (4 biological replicates per Neg, L, and LM group) using an Illumina Novaseq 6000 platform generated 102,827 unigenes. A total of 531 differentially expressed genes (DEGs) were common to both infected groups relative to the Neg group. GO and KEGG enrichment analyses highlighted key biological processes and pathways: up-regulated DEGs were associated with the cell cycle, antigen processing and presentation, and signal transduction, while down-regulated DEGs were linked to cholesterol metabolism, phagosome function, and fat digestion and absorption. qRT-PCR validation of 8 DEGs confirmed consistent expression patterns with RNA-seq data. These findings elucidate the tissue-specific infection patterns of P. beihaiensis in Hong Kong oysters in the digestive gland and provide critical insights into host-parasite interactions.

Heteroaggregation with microalgae masks charge-dependent accumulation but amplifies charge-dependent toxicity of nanoplastics in mussels.

Potential of the bivalve Perna perna as bioindicator of eutrophication in tropical coastal ecosystems: carbon and nitrogen stable isotopes, fatty acids and shell morphometry.

How BPA-free alternative fluorene-9-bisphenol affects the freshwater ecosystems: acute toxicity, immunology and biochemical responses of mussels?

Combined effects of an antidepressant (fluoxetine) and hypoxia on Mytilus edulis reproduction and metabolism.

Is acyl-CoA cholesterol acyltransferase 2 the enzyme responsible for the esterification of okadaic acid in bivalves?

How the Mediterranean mussel Mytilus galloprovincialis responds to multiple environmental challenges: Vibrio splendidus and hydrocarbon mixture.

The present study evaluates the ecotoxicological effects of Dotarem (DOTA), a gadolinium-based contrast agent frequently detected in wastewater, on the marine clam Ruditapes decussatus. Clams were exposed for 7days to three concentrations of DOTA (C1 = 12.5µgL-1, C2 = 25µgL-1, C3 = 50µgL-1). The study aimed to investigate multiple biomarkers related to physiological, oxidative, neurotoxic, and histopathological responses. Filtration rate was significantly reduced after exposure, from 8.18 ± 4.22mgh-1ind-1 in controls to 2.03 ± 0.6mgh-1ind-1 at the highest concentration, indicating impaired feeding activity. Antioxidant enzymes, catalase (CAT), glutathione-S-transferase (GST) and the cellular damage biomarker (malondialdehyde, MDA) displayed concentration- and organ-dependent responses, reflecting oxidative stress induced by DOTA. Acetylcholinesterase (AChE) activity decreased markedly in the gills, independent of dose and showed a dose-dependent inhibition in the digestive gland (p < 0.0001), demonstrating neurotoxic effects. Histopathological analyses revealed lesions in both organs, including cellular infiltrations, vacuolization, and necrosis, with severity increasing with DOTA concentration. Overall, this study highlights that Dotarem acts as a significant environmental contaminant, affecting multiple physiological and biochemical processes in R. decussatus, and emphasizes the need to monitor emerging contaminants in aquatic ecosystems.

Toxicopathology and expression of a CYP1-like gene in gills and digestive gland of wild Mediterranean mussel (Mytilus galloprovincialis) from sites with different contamination profiles and exposed to B[a]P.

Unveiling the mechanisms of oxidative stress-mediated multi-pathway programmed cell death in Ruditapes philippinarum exposed to butylated hydroxytoluene (BHT).

Ocean acidification does not affect the trophic transfer of Ag, Co, and Zn in the cuttlefish Sepia officinalis.

Effects of medium-term exposure to a high concentration of polystyrene nanoplastics in Chilean mussels (Mytilus chilensis).

Ecotoxicological effects of deep-sea sediments from polymetallic nodule fields in the marine mussel Mytilus galloprovincialis.

Molecular characterization of peroxiredoxin 5 from Mytilus coruscus and its roles in antioxidant defense and immune regulation.

High-resolution LA-ICP-MS imaging combined with attention-enhanced residual network reveal cadmium-induced metal distribution heterogeneity and toxicity in Mytilus galloprovincialis.

Tritium forms and food availability modulate biological effects in marine mussels.

The combined effects of polystyrene microplastics and temperature stress on Mytilus galloprovincialis, Lamarck, 1819.

Due to the structural complexity of the crustacean digestive system, this study characterizes the three-dimensional (3D) morphology and histology of the juvenile Penaeus vannamei alimentary tract using synchrotron radiation X-ray tomographic microscopy (SR-XTM) and H&E staining. SR-XTM volumetric imaging effectively reveals the structural interconnections among the pyloric stomach (PS), hepatopancreas (HP), and midgut (MG). Histological analysis further distinguishes the regional processing of fine and coarse chyme, which are segregated by a pair of lateral pyloric valves (LPVs). These valves function as mechanical barriers to prevent mixing of coarse and fine chyme within the anterior MG. Furthermore, this study identifies a secondary communication pathway, a sub-LPV channel, that enables a direct connection between the MG and the HP. In situ hybridization of EHP-specific transcripts identifies significant Enterocytozoon hepatopenaei (EHP) infection in cells lining the primary hepatopancreatic chamber and proximal regions of the secondary and tertiary HP tubules. Given that the gastric sieve restricts pathogen transmission by particle size, our findings suggest the sub-LPV channel serves as a critical alternative route for the oral transmission of EHP spores. This study provides a foundational structural framework for understanding shrimp digestive anatomy and host-pathogen internalization.

The contamination of aquatic ecosystems by textile microfibers is a growing concern. Because bivalves continuously filter large volumes of water, they are particularly vulnerable to microfiber exposure, making them important indicators of emerging pollutants. The ingestion of microfibers by marine organisms can lead to bioaccumulation and biomagnification across the food chain, putting higher trophic levels at risk. This study evaluated the sublethal effects of three textile microfiber types and a mixed-fiber treatment (conventional cotton, polyester, their mixture and, organic cotton) at two exposure concentrations, a wastewater-impacted hotspot concentration (0.11 mg. L-1) and a higher level (1.00 mg. L-1), on the gills, and digestive gland, of Crassostrea gasar across 7, 14, and 21 days. Responses were assessed using biomarkers of biotransformation, antioxidant defenses, oxidative damage, genotoxicity, neurotoxicity, cytotoxicity, and survival rate. Exposure to microfibers induced multi-system toxicity with organ-specific response patterns. Reduced glutathione (GSH) levels and glutathione S-transferase (GST) activity increased in the gills but decreased in the digestive gland, whereas lipid peroxidation and DNA damage occurred in both organs. In addition, survival decreased significantly in oysters exposed to conventional cotton and mixed fibers at both concentrations (Log-rank test: cotton, P = 0.0302; mix, P = 0.0247). Among the evaluated microfiber types, organic cotton elicited the most pronounced integrated sublethal responses, as shown by notable biochemical and cellular disturbances. However, conventional cotton and mixed fibers had a more significant impact on survival, indicating that the microfiber hazard varies depending on the biological endpoint considered. These findings demonstrate that both natural and synthetic textile microfibers impair C. gasar's redox and cellular homeostasis, leading to oxidative damage and reduced survival, underscoring their ecological relevance as emerging contaminants, and the magnitude and dynamics of this toxicity depend on fiber type and exposure duration.