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Abstract Brevetoxins are a type of neurotoxin produced in red tide blooms. Northern quahogs (M. mercenaria) are extensively used in commercial aquaculture farming, and early-stage metabolomics studies can provide early warnings of brevetoxins for farmers. In this study, NMR-based metabolomics was performed to investigate the response of clam gills and digestive glands under a series of sublethal doses of brevetoxins. Our study showed that the brevetoxin PbTx-2 had minimal influence on the physical activities of M. mercenaria for a short exposure time (24 hours). However, major metabolic level perturbations were observed in the clam gill extracts from the 1 ppb treatment. In addition, in the low concentration (0.1 ppb) study, clam gills showed combinational metabolite perturbations, as observed by an OPLS-DA study. The highly disturbed metabolites in the gill samples were the upregulated serine, glucose, hypotaurine, and glycine and the downregulated lactate, leucine, isoleucine, threonine, biotin, taurine, and valine. The results indicated that the brevetoxin PbTx-2 potentially affects glycolysis, glycine, serine, and threonine metabolism, taurine and hypotaurine metabolism, and biotin metabolism. While the digestive gland had less significantly changed metabolites, the potential combinational metabolite changes from PCA were observed from the 5-ppb treatment. Glucose and glycine are the primary metabolites that showed high contributions to the OPLS-DA model, which indicates the potential influence of digestive activities. The study indicated that metabolomic analysis of the gills and digestive glands of M. mercenaria is a feasible method to monitor the toxicity of brevetoxins, especially under sublethal doses in marine water.
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Metabolomics study on southern hard clams ( Mercenaria campechiensis ) response to diclofenac exposure
The exposure of ecologically critical invertebrates to pharmaceutically active compounds in aquatic environments has been one of the major concerns over the past decade, which also adds serious risk to the aquatic ecosystem. However, the metabolic level perturbations in invertebrates in response to sub-lethal doses of pharmaceuticals are still rarely studied, especially in the marine coastal environment. In this study, the diclofenac regulation of southern hard clam Mercenaria campechiensis metabolites at different time points and concentrations was investigated using NMR-based metabolomics. As a result, clam metabolic profile perturbations were observed under both low and high concentrations of diclofenac exposure in one week according to principal component analysis (PCA) and partial least squares-discriminant analysis (PLS-DA); however, the potential influenced metabolic pathways were distinctly different. The low-concentration group showed significant taurine upregulation, which indicated self-protection from osmotic stress. However, the metabolites succinate, alanine, and glutamate were significantly upregulated at the relatively high concentration of diclofenac, which was a sign of anaerobic activities. The metabolic profile perturbations in week 2 showed high similarity in both low- and high-concentration groups, and the osmotic protectants betaine and taurine were significantly downregulated. The study indicated the early markers of diclofenac exposure in M. campechiensis , which provided pioneering results for monitoring the toxicity of pharmaceuticals to marine coastal water.
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- Award ID(s):
- 2245530
- PAR ID:
- 10420915
- Date Published:
- Journal Name:
- Environmental Science: Advances
- Volume:
- 2
- Issue:
- 1
- ISSN:
- 2754-7000
- Page Range / eLocation ID:
- 107 to 114
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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- Free Publicly Accessible Full Text
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Accepted Manuscript1.0
- Journal Article:
- https://doi.org/10.1039/D2VA00207H
