Linking chemical exposure to lipid homeostasis: A municipal waste water treatment plant influent is obesogenic for zebrafish larvae.

Obesity, a risk factor for the development of type-2 diabetes, hypertension, cardiovascular disease, hepatic steatosis and some cancers, has been ranked in the top 10 health risk in the world by the World Health Organization. Despite the growing body of literature evidencing an association between the obesity epidemic and specific chemical exposure across a wide range of animal taxa, very few studies assessed the effects of chemical mixtures and environmental samples on lipid homeostasis. Additionally, the mode of action of several chemicals reported to alter lipid homeostasis is still poorly understood. Aiming to fill some of these gaps, we combined an in vivo assay with the model species zebrafish (Danio rerio) to screen lipid accumulation and evaluate expression changes of key genes involved in lipid homeostasis, alongside with an in vitro transactivation assay using human and zebrafish nuclear receptors, retinoid X receptor α and peroxisome proliferator-activated receptor γ. Zebrafish larvae were exposed from 4 th day post-fertilization until the end of the experiment (day 18), to six different treatments: experimental control, solvent control, tributyltin at 100 ng/L Sn and 200 ng/L Sn (positive control), and wastewater treatment plant influent at 1.25% and 2.5%. Exposure to tributyltin and to 2.5% influent led to a significant accumulation of lipids, with white adipose tissue deposits concentrating in the perivisceral area. The highest in vitro tested influent concentration (10%) was able to significantly transactivate the human heterodimer PPARγ/RXRα, thus suggesting the presence in the influent of HsPPARγ/RXRα agonists. Our results demonstrate, for the first time, the ability of complex environmental samples from a municipal waste water treatment plant influent to induce lipid accumulation in zebrafish larvae.

Effects of Tributyltin and Other Retinoid Receptor Agonists in Reproductive-Related Endpoints in the Zebrafish (Danio rerio).

Both field and experimental data examined the influence of exposure to environmental contaminant tributyltin (TBT) on marine organisms. Although most attention focused on the imposex phenomenon in gastropods, adverse effects were also observed in other taxonomic groups. It has been shown that imposex induction involves modulation of retinoid signaling in gastropods. Whether TBT influences similar pathways in fish is yet to be addressed. In this study, larvae of the model teleost Danio rerio were exposed to natural retinoids, all-trans-retinoic acid, 9-cis-retinoic acid, and all-trans-retinol, as well as to the RXR synthetic pan-agonist methoprene acid (MA) and to TBT. Larvae were exposed to TBT from 5 days post fertilization (dpf) to adulthood, and reproductive capacity was assessed and correlated with mode of action. TBT significantly decreased fecundity at environmentally relevant levels at 1 µg TBT Sn/g in diet. Interestingly, in contrast to previous reports, TBT altered zebrafish sex ratio toward females, whereas MA exposure biased sex toward males. Since fecundity was significantly altered in the TBT-exposed group with up to 62% decrease, the potentially affected pathways were investigated. Significant downregulation was observed in brain mRNA levels of aromatase b (CYP19a1b) in females and peroxisome proliferator activated receptor gamma (PPARg) in both males and females, suggesting an involvement of these pathways in reproductive impairment associated with TBT.

Experimental data from the development of Lymnaea stagnalis embryo test for chemicals hazard assessment.

This study aimed to contribute to the development of an embryo-test using the gastropod Lymnaea stagnalis, identified by the Organization for Economic Co-operation and Development (OECD) as a potential invertebrate test animal model. Together with the Potamopyrgus antipodarum, were the first mollusc models to be included in the organization testing guidelines. The focus was on validating an embryo toxicity test to cover the sensitive embryogenesis phase and on obtaining testing information on all of the model life cycle stages, contributing to close an identified gap within this context. Adhering to OECD guidelines, namely the L. stagnalis reproductive test, the study examined mortality rates, abnormality rates, development, growth, hatching rates, hearth rates, and pre-testing media suitability, during the embryogenesis, and the obtained dataset made available for further studies. Cadmium was chosen as the positive test compound due to its well-studied nature and the model's proven sensitivity to the compound, working as a reference compound for the test development. The data were collected in two 12-day assays under consistent conditions, each using 144 L. stagnalis embryos (<24 h old) from 6 egg masses (288 embryos total). Six 48-well microplates were utilized per assay, accommodating five different cadmium concentrations (32, 70, 155, 341, 750 µg/L) and a control group. Recorded parameters encompassed developmental stage, embryo position within the chorion, developmental abnormalities, hatchings, and mortality. Data analysis involved classifying embryos based on developmental stage and position, taking an exploratory approach to define the relevance of the different parameters in the compound hazard assessment during the embryogenesis. Measurements considered embryo area, perimeter, length, height, width, interocular distance, and heart rate. This dataset does not provide treated information but the raw data obtained during the proposed metodological development and toxicity testing process. The purpose of this article is to make the obtained raw data available, clearly defining the acquisition methodology to provide a comparison basis for future or existent works within this context.

Use of illicit drugs, alcohol and tobacco in Spain and Portugal during the COVID-19 crisis in 2020 as measured by wastewater-based epidemiology.

The COVID-19 pandemic spread rapidly worldwide in the year 2020, which was initially restrained by drastic mobility restrictions. In this work, we investigated the use of illicit drugs (amphetamine, methamphetamine, ecstasy, cocaine and cannabis), and licit substances of abuse (alcohol and tobacco) during the earlier months (March-July 2020) of the pandemic restrictions in four Spanish (Bilbao and its metropolitan area, Vitoria-Gasteiz, Castellón and Santiago de Compostela) and two Portuguese (Porto and Vila do Conde) locations by wastewater-based epidemiology (WBE). The results show that no methamphetamine was detected in any of the locations monitored, while amphetamine use was only detectable in the two locations from the Basque Country (Bilbao and its metropolitan area and Vitoria-Gasteiz), with high estimated average usage rates (700-930 mg day-1 1000 inhabitant-1). The remaining substances were detected in all the investigated catchment areas. In general, no remarkable changes were found in population normalized loads compared to former years, except for cocaine (i.e. its main metabolite, benzoylecgonine). For this drug, a notable decrease in use was discernible in Castellón, while its usage in Porto and Santiago de Compostela seemed to continue in a rising trend, already initiated in former years. Furthermore, two events of ecstasy (3,4-methylenedioxymethamphetamine, MDMA) dumping in the sewage network were confirmed by enantiomeric analysis, one in Santiago de Compostela just prior the lockdown and the second one in the Bilbao and its metropolitan area in July after relieving the more stringent measures. The latter could also be associated with a police intervention. The comparison of WBE with (web) survey data, which do not provide information at a local level, points towards contradictory conclusions for some of the substances, thereby highlighting the need for stable WBE networks capable of near real-time monitoring drug use.

A genome assembly of the Atlantic chub mackerel (Scomber colias): a valuable teleost fishing resource.

The Atlantic chub mackerel, Scomber colias (Gmelin, 1789), is a medium-sized pelagic fish with substantial importance in the fisheries of the Atlantic Ocean and the Mediterranean Sea. Over the past decade, this species has gained special relevance, being one of the main targets of pelagic fisheries in the NE Atlantic. Here, we sequenced and annotated the first high-quality draft genome assembly of S. colias, produced with PacBio HiFi long reads and Illumina paired-end short reads. The estimated genome size is 814 Mbp, distributed into 2,028 scaffolds and 2,093 contigs with an N50 length of 4.19 and 3.34 Mbp, respectively. We annotated 27,675 protein-coding genes and the BUSCO analyses indicated high completeness, with 97.3% of the single-copy orthologs in the Actinopterygii library profile. The present genome assembly represents a valuable resource to address the biology and management of this relevant fishery. Finally, this genome assembly ranks fourth in high-quality genome assemblies within the order Scombriformes and first in the genus Scomber.

Data collection on the use of embryo bioassays with aquatic animals for toxicity testing and hazard assessment of emerging pollutants.

A thorough bibliographic survey on the use of embryo-tests with aquatic animals for toxicity testing was performed. The data regarding to the compounds sensitivity (NOEC, LOEC, EC50 and LC50), the available resources for the different animal models (knowledge on the life-cycle, amenability for laboratory breeding, number of embryos produced and reproductive strategy, genomic and transcriptomic resources), together with the European pieces of legislation regarding to animal testing and the available testing guidelines of national and international agencies (OECD, EPA, ISO, ASTM, ICES) were gathered, aiming to the standardization of new embryo-test model species for toxicity testing of new and existing compounds. The data contained in this Data in Brief article is presented and discussed in the review article with the title Embryo bioassays with aquatic animals for toxicity testing and hazard assessment of emerging pollutants: a review [1]. The dataset is provided with this article as a supplementary file.

Embryo bioassays with aquatic animals for toxicity testing and hazard assessment of emerging pollutants: A review.

This review article gathers the available information on the use of embryo-tests as high-throughput tools for toxicity screening, hazard assessment and prioritization of new and existing chemical compounds. The approach is contextualized considering the new legal trends for animal experimentation, fostering the 3R policy, with reduction of experimental animals, addressing the potential of embryo-tests as high-throughput toxicity screening and prioritizing tools. Further, the current test guidelines, such as the ones provided by OECD and EPA, focus mainly in a limited number of animal lineages, particularly vertebrates and arthropods. To extrapolate hazard assessment to the ecosystem scale, a larger diversity of taxa should be tested. The use of new experimental animal models in toxicity testing, from a representative set of taxa, was thoroughly revised and discussed in this review. Here, we critically review current tools and the main advantages and drawbacks of different animal models and set researcher priorities.

Effects of chronic exposure to lead, copper, zinc, and cadmium on biomarkers of the European eel, Anguilla anguilla.

Exposure to specific metallic compounds can cause severe deleterious modifications in organisms. Fishes are particularly prone to toxic effects from exposure to metallic compounds via their environment. Species that inhabit estuaries or freshwater environments can be chronically affected by persistent exposure to a large number of metallic compounds, particularly those released by industrial activities. In this study, we exposed yellow eels (European eel, Anguilla anguilla) for 28 days to environmentally relevant concentrations of four specific metals; lead (300, 600, and 1,200 µg/l), copper (40, 120, and 360 µg/l), zinc (30, 60, and 120 µg/l) and cadmium (50, 150, and 450 µg/l). The selected endpoints to assess the toxicological effects were neurotransmission (cholinesterasic activity in nervous tissue), antioxidant defense, and phase II metabolism (glutathione-S-transferase [GST] activity, in both gills and liver tissues), and peroxidative damage. The results showed an overall lack of effects on acetylcholinesterase for all tested metals. Lead, copper, and cadmium exposure caused a significant, dose-dependent, increase in GST activity in gill tissue. However, liver GST only significantly increased following zinc exposure. No statistically significant effects were observed for the thiobarbituric acid reactive substances assay, indicating the absence of peroxidative damage. These findings suggest that, despite the occurrence of an oxidative-based response after exposure to lead, copper, and cadmium, this had no consequence in terms of peroxidative membrane damage; furthermore, cholinergic neurotoxicity caused by lead, copper, and cadmium did not occur. The implications of these results are further discussed.