Changes in fatty acid profile of Holothuria forskali muscle following acute mercury exposure

Exposure to tebufenpyrad interrupts histo-architecture and fatty acid compositions of carpet shell clam Ruditapes decussatus

Tebufenpyrad (TUBF) is classified as a pyrazole acaricide and insecticide and is extensively utilized in greenhouse environments in several countries. Nevertheless, limited data exists regarding the potential reproductive toxicity of TUBF, particularly in non-target species. In this study, the fatty acid (FA) composition, the histopathology aspects, and redox status were assessed in the digestive gland of the clam Ruditapes decussatus following short-term exposure (96 h) to a series of concentrations (50, 100, and 200 µgL-1) of TUBF. Our findings indicated that TUBF induced oxidative stress, as evidenced by elevated levels of hydrogen peroxide (H2O2), malondialdehyde (MDA), and lipid peroxides (LOOH) in the treated groups. TUBF was also found to disrupt the enzymatic (catalase) and non-enzymatic (reduced glutathione) antioxidant defense systems. Additionally, TUBF was found to disrupt the FA composition. Overall, alterations in saturated (SFA), monounsaturated (MUFA), and polyunsaturated (PUFA) fatty acids, including certain essential FAs (such as LA, ARA, EPA, and DHA), exhibited differential compensatory/adaptive processes in R. decussatus depending on the concentration of TUBF. Furthermore, both examined organs showed various histological impairments, such as lipofuscin accumulation, infiltrative inflammations, and changes in digestive tubules, which provide additional evidence of TUBF toxic effects.

Impacts of engineered iron nanoparticles on oxidative stress, fatty acid composition, and histo-architecture of the smooth scallop Flexopecten glaber

Engineered iron nanoparticles are widely used in environmental remediation, yet their potential toxic effects on marine biota remain poorly elucidated. This study aimed to gain insight into the nanoscale zero-valent iron (NZVI) toxicity mechanisms for marine invertebrates. Aside from the effect on oxidative status and histopathology, the effect of NZVI on lipid metabolism in bivalves was studied for the first time. To this end, specimens of Flexopecten glaber were exposed to ascending concentrations (0.5, 1, and 1.5 mg/L) of NZVI for 96 h. Results illustrate differential patterns of iron accumulation in the gills and the digestive gland. By increasing NZVI concentrations, the total iron level tended to markedly increase in the gills and decrease in the digestive gland, reaching 132 and 37.6 μg/g DW, respectively, in the specimens exposed to 1.5 mg/L. Biochemical and cellular biomarkers highlighted that NZVI caused oxidative stress (measured as hydrogen peroxide, malondialdehyde, and advanced oxidation protein product levels) and alterations of antioxidant defense systems, including reduced glutathione, non-protein thiol, glutathione peroxidase, superoxide dismutase, and catalase. Modulation of lipid metabolism with changed fatty acid compositions (mainly an increase in the saturation and a decrease in unsaturation levels) was also observed in both gills and digestive gland. Moreover, several histological damages, including lipofuscin accumulation, infiltrative inflammations, and digestive tubule alterations, were observed in the two studied organs, providing supplementary evidence regarding the toxic effect of NZVI. This study adds to the growing body of evidence pointing to the hazardous impacts of iron NPs on aquatic ecosystems.

Glyphosate exposure modulates lipid composition, histo-architecture and oxidative stress status and induces neurotoxicity in the smooth scallop Flexopecten glaber

Glyphosate is the most sprayed pesticide across the globe. Its toxicity to non-target marine organisms has recently piqued the scientific community's interest. Therefore, the purpose of this study is to investigate the potentially toxic effects of glyphosate on scallops, an ecologically and economically important bivalve group. To do that, specimens of the smooth scallop Flexopecten glaber were exposed to different concentrations (10, 100, and 1000 μg L-1) of the technical-grade glyphosate acid (GLY) for 96 h. The detrimental effects of this pollutant were assayed at cellular and tissular levels. The obtained results showed that the GLY was able to induce oxidative stress in the gills and the digestive gland of F. glaber as revealed by the enhanced hydrogen peroxide (H2O2), protein carbonyls (PCO), malondialdehyde (MDA), and lipid peroxides (LOOH) levels and the altered antioxidant defense system (the glutathione GSH content and the superoxide dismutase (SOD) activity). Additionally, GLY was found to alter the fatty acid profile, to exert a neurotoxic effect through the inhibition of the acetylcholinesterase (AChE) activity, and to provoke several histopathological damages in the two organs studied. The obtained results revealed that the pure form of GLY may exert toxic effects on F. glaber even at relatively low concentrations.