Toxicological effects and bioaccumulation of fullerene C60 (FC60) in the marine bivalve Ruditapes philippinarum

Bioconcentration, biotransformation, and transcriptomic impact of the UV-filter 4-MBC in the manila clam Ruditapes philippinarum

Ultraviolet filters (UV-filters) are compounds extensively used in personal care products. These compounds are produced at increasing rates and discharged into marine ecosystems in unknown quantities and with no regulation, making them emerging contaminants. Among those, the UV-filter 4-Methylbenzylidene camphor (4-MBC) is used in a variety of personal care products such as sunscreens, soaps, or lipsticks. This high consumption has resulted in its presence in various environmental matrices at in concentrations ranging from ng to μg L-1. Very little is known, however, about the possible adverse effects in exposed non-target organisms. Our study presents novel data on the bioconcentration, toxicokinetics, and molecular effects of 4-MBC in a marine bivalve species of commercial interest, Ruditapes philippinarum (Manila clam). Organisms were exposed at two different concentrations (1.34 and 10.79 μg L-1) of 4-MBC for 7 days, followed by a 3-day depuration period (clean sea waters). Bioconcentration factors (BCF) were 3562 and 2229 L kg-1 for the low and high exposure concentrations, respectively, making this pollutant bioaccumulative according to REACH criteria. Up to six 4-MBC biotransformation products (BTPs)were identified, 2 of them for the first time. Transcriptomic analysis revealed between 658 and 1310 differently expressed genes (DEGs) after 4-MBC exposure. Functional and enrichment analysis of the DEGs showed the activation of the detoxification pathway to metabolize and excrete the bioconcentrated 4-MBC, which also involved energy depletion and caused an impact on the metabolism of carbohydrates and lipids and in the oxidative phosphorylation pathways. Oxidative stress and immune response were also evidenced through the activation of cathepsins and the complement system. Such elucidation of the mode of action of a ubiquitous pollutant such as 4-MBC at the molecular level is valuable both from an environmental point of view and for the sustainable production of Manila clam, one of the most cultivated mollusk species worldwide.

Fullerene C60 protects against 7,12-dimethylbenz [a] anthracene (DMBA) induced-pancreatic damage via NF-κB and Nrf-2/HO-1 axis in rats

The objective of this investigation was to investigate the protective effects of fullerene C60 nanoparticle against pancreatic damage experimentally induced by 7,12-dimethylbenz [a] anthracene (DMBA) in female rats. Fullerene C60 nanoparticle was administered to rats 5 times a week by oral gavage (o.g) at 1.7 mg/kg bw 7 days after DMBA administration. 60 Wistar albino female rats divided to four groups; Groups: (1) Control group: Fed with standard diet; (2) Fullerene C60 group: Fullerene C60 (1.7 mg/kg bw); (3) DMBA group: DMBA (45 mg/kg bw); (4) Fullerene C60 + DMBA group: Fullerene C60 (1.7 mg/kg bw) and DMBA (45 mg/kg bw). Lipid peroxidation malondialdehyde (MDA), catalase activity (CAT) and glutathione (GSH) levels in pancreatic tissue were determined by spectrophotometer. Protein expression levels of p53, HO-1, p38-α (MAPK), Nrf-2, NF-κB and COX-2 in pancreatic tissue were determined by western blotting technique. In our findings, compared to the group given DMBA, MDA levels and p38-α, NF-κB and COX-2 levels decreased, CAT activity, GSH level, total protein density and p53, HO-1, Nrf-2 levels in the groups given fullerene C60 nanoparticle an increase in expression levels was observed. Our results showed that fullerene C60 nanoparticle may be more beneficial in preventing pancreatic damage.

Prediction models on biomass and yield of rice affected by metal (oxide) nanoparticles using nano-specific descriptors

The use of in silico tools to investigate the interactions between metal (oxide) nanoparticles (NPs) and plant biological responses is preferred because it allows us to understand molecular mechanisms and improve prediction efficiency by saving time, labor, and cost. In this study, four models (C5.0 decision tree, discriminant function analysis, random forest, and stepwise multiple linear regression analysis) were applied to predict the effect of NPs on rice biomass and yield. Nano-specific descriptors (size-dependent molecular descriptors and image-based descriptors) were introduced to estimate the behavior of NPs in plants to appropriately represent the wide space of NPs. The results showed that size-dependent molecular descriptors (e.g., E-state and connectivity indices) and image-based descriptors (e.g., extension, area, and minimum ferret diameter) were associated with the behavior of NPs in rice. The performance of the constructed models was within acceptable ranges (correlation coefficient ranged from 0.752 to 0.847 for biomass and from 0.803 to 0.905 for yield, while the accuracy ranged from 64% to 77% for biomass and 81% to 89% for yield). The developed model can be used to quickly and efficiently evaluate the impact of NPs under a wide range of experimental conditions and sufficient training data.

Hazardous elements present in coal nanoparticles in a Caribbean port region in Colombia

Scientific works examining coal-derived nanoparticles (NPs) containing potentially toxic elements (PTEs) confined in marine suspended sediments (MSSs) in port regions worldwide is an understudied topic, despite the fact that coal NPs have tremendous negative impacts on marine estuaries. The general objective of this study is to analyze the NP levels of coal, including PTEs, contained within MSSs in the general vicinity of the largest Caribbean port in Colombia. The morphology, size, chemical composition, and agglomeration states of NPs within MSSs of the sampled beaches were calculated through modern electron microscopy. The methodology used to detect chemical elements, unfortunately with EDS, it is not possible to precisely specify the chemical elements of low atomic weight (e.g. H, O, F, etc.) Therefore, with the EDS available today, it is only possible to have an idea of the chemical composition of each detected particle. Thus, it was possible to obtain the average frequency of the chemical elements identified in the 23 analyzed sampling points. Through the results, more than one thousand particles were detected in the most abundant phases, thus, the most frequent particles in the results of this manuscript were described. Sample point 8, located closest to the coal export port, had a higher concentration of nano-toxic elements (Al, Fe, Si, K, Mg, K) most concerning for human health in addition to being harmful to marine life. This study suggests that public policies dealing with MSS pollution need to be discussed by public managers to avoid further and sustained environmental degradation. The need to create projects will subsidize legacy liabilities generated by coal in seaports in other regions of the world.

Zinc oxide, titanium dioxide and C60 fullerene nanoparticles, alone and in mixture, differently affect biomarker responses and proteome in the clam Ruditapes philippinarum

Continuous release of nanoparticles (NPs) into marine coastal environments results in an increased risk of exposure to complex NP mixtures for marine organisms. However, to date, the information on the effects at molecular and biochemical levels induced by the exposure to NPs, singly and as a mixture, is still scant. The present work aimed at exploring the independent and combined effects and the mechanism(s) of action induced by 7-days exposure to 1 μg/L nZnO, 1 μg/L nTiO₂ and 1 μg/L FC₆₀ fullerene in the Manila clam Ruditapes philippinarum, using a battery of immunological and oxidative stress biomarkers in haemolymph, gills and digestive gland. In addition, proteomics analyses were performed in gills and the digestive gland, where NP bioaccumulation was also assessed. Increased bioaccumulation of single NPs and the mixture was linked with increased oxidative stress and higher damage to proteins, lipids and DNA in all tissues analysed. The proteomics approach highlighted protein modulation in terms of abundance and damage (higher redox-thiol and carbonylated groups content). In particular, the modulated proteins (16 in gills and 18 in digestive gland) were mostly related to cytoskeleton and energetic metabolism. The digestive gland was the tissue more affected. For all biomarkers measured, increased detrimental effects were observed in the mixture compared to single NP exposures.

Toxic Effect of Fullerene and Its Derivatives upon the Transmembrane β2-Adrenergic Receptors

Numerous experiments have revealed that fullerene (C₆₀) and its derivatives can bind to proteins and affect their biological functions. In this study, we explored the interaction between fullerine and the β₂-adrenergic receptor (β₂AR). The MD simulation results show that fullerene binds with the extracellular loop 2 (ECL2) and intracellular loop 2 (ICL2) of β₂AR through hydrophobic interactions and π–π stacking interactions. In the C₆₀_in1 trajectory, due to the π–π stacking interactions of fullerene molecules with PHE and PRO residues on ICL2, ICL2 completely flipped towards the fullerene direction and the fullerene moved slowly into the lipid membrane. When five fullerene molecules were placed on the extracellular side, they preferred to stack into a stable fullerene cluster (a deformed tetrahedral aggregate), and had almost no effect on the structure of β₂AR. The hydroxyl groups of fullerene derivatives (C₆₀(OH)_X, X represents the number of hydroxyl groups, X = 4, 8) can form strong hydrogen bonds with the ECL2, helix6, and helix7 of β₂AR. The hydroxyl groups firmly grasp the β₂AR receptor like several claws, blocking the binding entry of ligands. The simulation results show that fullerene and fullerene derivatives may have a significant effect on the local structure of β₂AR, especially the distortion of helix4, but bring about no great changes within the overall structure. It was found that C₆₀ did not compete with ligands for binding sites, but blocked the ligands’ entry into the pocket channel. All the above observations suggest that fullerene and its derivatives exhibit certain cytotoxicity.

Analysis of Nanomaterials on Biological and Environmental Systems and New Analytical Methods for Improved Detection

The advancing field of nanoscience has produced lower mass, smaller size, and expanded chemical composition nanoparticles over recent years. These new nanoparticles have challenged traditional analytical methods of qualification and quantification. Such advancements in nanoparticles and nanomaterials have captured the attention of toxicologists with concerns regarding the environment and human health impacts. Given that nanoparticles are only limited by size (1–100 nm), their chemical and physical characteristics can drastically change and thus alter their overall nanotoxicity in unpredictable ways. A significant limitation to the development of nanomaterials is that traditional regulatory and scientific methods used to assess the biological and environmental toxicity of chemicals do not generally apply to the assessment of nanomaterials. Significant research effort has been initiated, but much more is still needed to develop new and improved analytical measurement methods for detecting and quantitating nanomaterials in biological and environmental systems.

Effects of the Fragrance Galaxolide on the Biomarker Responses of the Clam Ruditapes philippinarum

The musk fragrance Galaxolide® (HHCB) is widely used in personal care and household products. Its large use leads to a continuous release of the compound into aquatic environments. Although some studies on the presence of HHCB in ecosystems and biota have been conducted, limited data about its effects on organism biomarkers are available. This study aimed at investigating both cellular and biochemical effects of HHCB in the clam Ruditapes philippinarum. Mussels were exposed for 7, 14 and 21 days to 100 ng/L and 500 ng/L of HHCB in seawater, and the effects on haemocyte parameters and antioxidant enzyme activities in the gills and digestive gland were evaluated. In addition, the neurotoxic potential of HHCB and its capacity to cause oxidative damage to proteins were assessed. Overall, our results demonstrated that exposure to HHCB was able to induce changes in biomarker responses of mussels, mainly at the cellular level.