Pesticide Pollution: Detrimental Outcomes and Possible Mechanisms of Fish Exposure to Common Organophosphates and Triazines

Effects of trichlorfon on ecotoxicological biomarkers in farmed Colossoma macropomum (tambaqui)

Producers of fish have been looking for viable alternatives for the management of Colossoma macropomum (tambaqui) in confinement systems in order to avoid the harm and subsequent losses caused by parasitic diseases. One alternative used by farmers is pesticides, such as trichlorfon, which has a genotoxic effect. Thus, this study aimed to evaluate the changes in gene expression due to the side effects of trichlorfon in tambaqui. Two treatments were used based on LC50-96h of 0.870 mg/L using 30% and 50% trichlorfon with exposure periods of 48, 72 and 96 h. For differential expression of the genes in the liver, real-time PCR was performed for the AChE, GST, CYP2J6, CYP2C8, 18S and GAPDH genes. After 96 h of exposure to trichlorfon, an alteration in the gene expression profile of the antioxidant defense system (GST) of the tambaqui was observed. It was also observed that this organophosphate did not affect the expression of genes related to the isoenzymes that are responsible for the biotransformation of xenobiotics in phase I (2J6 and 2C8) and cholinesterase AChE. It was concluded that the reduction in gene expression of GST suggests a decrease in metabolization capacity in phase II.

Cinnamon nanoemulsion mitigates acetamiprid-induced hepatic and renal toxicity in rats: biochemical, histopathological, immunohistochemical, and molecular docking analysis

Acetamiprid (ACDP) is a widely used neonicotinoid insecticide that is popular for its efficacy in controlling fleas in domestic settings and for pets. Our study aims to offer a comprehensive examination of the toxicological impacts of ACDP and the prophylactic effects of cinnamon nanoemulsions (CMNEs) on the pathological, immunohistochemical, and hematological analyses induced by taking ACDP twice a ‎week for 28 days. Forty healthy rats were divided into four groups (n = 10) at random; the first group served as control rats; the second received CMNEs (2 mg/Kg body weight); the third group received acetamiprid (ACDP group; 21.7 mg/Kg body weight), and the fourth group was given both ACDP and CMNEs by oral gavage. Following the study period, tissue and blood samples were extracted and prepared for analysis. According to a GC-MS analysis, CMNEs had several bioactive ingredients that protected the liver from oxidative stress by upregulating antioxidant and anti-inflammatory agents. Our findings demonstrated that whereas ACDP treatment considerably boosted white blood cells (WBCs) and lymphocytes, it significantly lowered body weight gain (BWG), red blood cells (RBCs), hemoglobin (Hb), hematocrit (HCT), and platelets (PLT). ACDP notably reduced antioxidant enzyme activities: superoxide dismutase (SOD), glutathione peroxidase (GPx), and catalase (CAT) and elevated hydrogen peroxide and malondialdehyde levels compared with other groups. ACDP remarkably raised alanine aminotransferase (ALT), aspartate amino transaminase (AST), and alkaline phosphatase (ALP) levels.Moreover, the histopathological and immunohistochemistry assays discovered a severe toxic effect on the liver and kidney following ACDP delivery. Furthermore, cyclooxygenase 2 (COX-2) + immunoexpression was enhanced after treatment with CMNEs. All of the parameters above were returned to nearly normal levels by the coadministration of CMNEs. The molecular docking of cinnamaldehyde with COX-2 also confirmed the protective potential of CMNEs against ACDP toxicity. Our findings highlighted that the coadministration of CMNEs along with ACDP diminished its toxicity by cutting down oxidative stress and enhancing antioxidant capacity, demonstrating the effectiveness of CMNEs in lessening ACDP toxicity.

Illicit Drugs in Surface Waters: How to Get Fish off the Addictive Hook

The United Nations World Drug Report published in 2022 alarmed that the global market of illicit drugs is steadily expanding in space and scale. Substances of abuse are usually perceived in the light of threats to human health and public security, while the environmental aspects of their use and subsequent emissions usually remain less explored. However, as with other human activities, drug production, trade, and consumption of drugs may leave their environmental mark. Therefore, this paper aims to review the occurrence of illicit drugs in surface waters and their bioaccumulation and toxicity in fish. Illicit drugs of different groups, i.e., psychostimulants (methamphetamines/amphetamines, cocaine, and its metabolite benzoylecgonine) and depressants (opioids: morphine, heroin, methadone, fentanyl), can reach the aquatic environment through wastewater discharge as they are often not entirely removed during wastewater treatment processes, resulting in their subsequent circulation in nanomolar concentrations, potentially affecting aquatic biota, including fish. Exposure to such xenobiotics can induce oxidative stress and dysfunction to mitochondrial and lysosomal function, distort locomotion activity by regulating the dopaminergic and glutamatergic systems, increase the predation risk, instigate neurological disorders, disbalance neurotransmission, and produce histopathological alterations in the brain and liver tissues, similar to those described in mammals. Hence, this drugs-related multidimensional harm to fish should be thoroughly investigated in line with environmental protection policies before it is too late. At the same time, selected fish species (e.g., Danio rerio, zebrafish) can be employed as models to study toxic and binge-like effects of psychoactive, illicit compounds.

Novel protective aspects of dietary polyphenols against pesticidal toxicity and its prospective application in rice-fish mode: A Review

The rice fish system represents an innovative and sustainable approach to integrated farming, combining rice cultivation with fish rearing in the same ecosystem. However, one of the major challenges in this system is the pesticidal pollution resulting from various sources, which poses risks to fish health and overall ecosystem balance. In recent years, dietary polyphenols have emerged as promising bioactive compounds with potential chemo-preventive and therapeutic properties. These polyphenols, derived from various plant sources, have shown great potential in reducing the toxicity of pesticides and improving the health of fish within the rice fish system. This review aims to explore the novel aspects of using dietary polyphenols to mitigate pesticidal toxicity and enhance fish health in the rice fish system. It provides comprehensive insights into the mechanisms of action of dietary polyphenols and their beneficial effects on fish health, including antioxidant, anti-inflammatory, and detoxification properties. Furthermore, the review discusses the potential application methods of dietary polyphenols, such as direct supplementation in fish diets or through incorporation into the rice fields. By understanding the interplay between dietary polyphenols and pesticides in the rice fish system, researchers can develop innovative and sustainable strategies to promote fish health, minimize pesticide impacts, and ensure the long-term viability of this integrated farming approach. The information presented in this review will be valuable for scientists, aqua-culturists, and policymakers aiming to implement eco-friendly and health-enhancing practices in the rice fish system.

Toxic effects of organophosphate pesticide monocrotophos in aquatic organisms: A review of challenges, regulations and future perspectives

In recent times, usage of pesticide, herbicides and synthetic fertilizers in farming lands has made the environment worse. The pesticide residues and toxic byproducts from agricultural lands were found to contaminate the aquatic ecosystem. The misuse of synthetic pesticide not only affects the environment, but also affects the health status of aquatic organisms. The organophosphate pesticide pollutants are emerging contaminants, which threatens the terrestrial and aquatic ecosystem. Monocrotophos (MCP) is an organophosphate insecticide, utilized on crops including rice, maize, sugarcane, cotton, soybeans, groundnuts and vegetables. MCP is hydrophilic in nature and their solubilizing properties reduce the soil sorption which leads to groundwater contamination. The half-life period of MCP is 17-96 and the half-life period of technical grade MCP is 2500 days if held stable at 38 °C in a container. MCP causes mild to severe confusion, anxiety, hyper-salivation, convulsion and respiratory distress in mammals as well as aquatic animals. The MCP induced toxicity including survival rate, behavioural changes, reproductive toxicity and genotoxicity in different aquatic species have been discussed in this review. Furthermore, the ultimate aim of this review is to highlight the international regulations, future perspectives and challenges involved in using the MCP.

DNA Methylation Profiling of Ovarian Tissue of Climbing Perch (Anabas testudienus) in Response to Monocrotophos Exposure

Epigenetic modifications like DNA methylation can alter an organism's phenotype without changing its DNA sequence. Exposure to environmental toxicants has the potential to change the resilience of aquatic species. However, little information is available on the dynamics of DNA methylation in fish gonadal tissues in response to organophosphates. In the present work, reduced-representation bisulfite sequencing was performed to identify DNA methylation patterns in the ovarian tissues of Anabas testudienus exposed to organophosphates, specifically monocrotophos (MCP). Through sequencing, an average of 41,087 methylated cytosine sites were identified and distributed in different parts of genes, i.e., in transcription start sites (TSS), promoters, exons, etc. A total of 1058 and 1329 differentially methylated regions (DMRs) were detected as hyper-methylated and hypo-methylated in ovarian tissues, respectively. Utilizing whole-genome data of the climbing perch, the DMRs, and their associated overlapping genes revealed a total of 22 genes within exons, 45 genes at transcription start sites (TSS), and 218 genes in intergenic regions. Through gene ontology analysis, a total of 16 GO terms particularly involved in ovarian follicular development, response to oxidative stress, oocyte maturation, and multicellular organismal response to stress associated with reproductive biology were identified. After functional enrichment analysis, relevant DMGs such as steroid hormone biosynthesis (Cyp19a, 11-beta-HSD, 17-beta-HSD), hormone receptors (ar, esrrga), steroid metabolism (StAR), progesterone-mediated oocyte maturation (igf1ar, pgr), associated with ovarian development in climbing perch showed significant differential methylation patterns. The differentially methylated genes (DMGs) were subjected to analysis using real-time PCR, which demonstrated altered gene expression levels. This study revealed a molecular-level alteration in genes associated with ovarian development in response to chemical exposure. This work provides evidence for understanding the relationship between DNA methylation and gene regulation in response to chemicals that affect the reproductive fitness of aquatic animals.

Assessing the toxicity of aegerolysin-based bioinsecticidal complexes using the sea urchin Paracentrotus lividus as model organism

The use of alternative solutions for pest management to replace pesticides in agriculture is of great interest. Proteinaceous complexes deriving from edible oyster mushrooms were recently proposed as environmentally friendly bioinsecticides. Such complexes, composed of ostreolysin A6 (OlyA6) and pleurotolysin B (PlyB), target invertebrate-specific membrane sphingolipids in insect's midgut, causing death through the formation of transmembrane pores. In this work, the potential impact of OlyA6/PlyB complexes was tested in the Mediterranean sea urchin Paracentrotus lividus, as an indicator of environmental quality. The ability of the fluorescently tagged OlyA6 to bind sea urchin gametes (sperm, eggs), the lipidome of sea urchin gametes, and the potential toxic effects and developmental anomalies caused by OlyA6/PlyB complexes on P. lividus early development (embryo, larvae) were investigated. The binding of the fluorescently tagged OlyA6 could be observed only in sea urchin eggs, which harbor OlyA6 sphingolipid membrane receptors, conversely to sperm. High protein concentrations affected sea urchin fertilization (>750 µg/L) and early development (> 375 µg/L in embryos; >100 µg/L in larvae), by causing toxicity and morphological anomalies in embryos and larvae. The main anomalies consisted in delayed embryos and incorrect migration of the primary mesenchyme cells that caused larval skeletal anomalies. The classification of these anomalies indicated a slight environmental impact of OlyA6/PlyB complexes at concentrations higher than 750 µg/L. Such impact should not persist in the marine environment, due to the reversible anomalies observed in sea urchin embryos and larvae that may promote defense strategies. However, before promoting the use of OlyA6/PlyB complexes as bio-pesticides at low concentrations, further studies on other marine coastal species are needed.

The Cellular Accumulation of Vehicle Exhaust Particulates Changes the Acidic pH Environment of Lysosomes in BEAS-2B Airway Epithelial Cells

Many people are exposed every day to vehicle exhaust particulates (VEPs), which are thought to be taken up by epithelial cells that are the first barrier in our biological defense. The study aim was to investigate how VEPs are processed in the lysosomal degradation system. BEAS-2B airway epithelial cells easily ingest VEPs and have been shown to accumulate in cells for several days, but no elevated cytotoxicity was observed over that time period. An analysis of 3D images confirmed the presence of VEPs in or near lysosomes, and an accumulation of VEPs resulted in an increase in the normal acidic pH in lysosomes and the extracellular release of the lysosomal enzyme β-hexosaminidase. Epithelial cells were thought to activate the lysosome-mediated secretion of extracellular vesicles to avoid damage caused by non-degradable foreign substances, such as VEPs, and as a side reaction, the acidic pH environment of the lysosomes could not be maintained.

Short-term effects of the strobilurin fungicide dimoxystrobin on zebrafish gills: A morpho-functional study

Strobilurins represent the most widely used class of fungicides nowadays andare considered relatively non-toxic to mammals and birds but highly toxic to aquatic biota. Dimoxystrobin is one of the novel strobilurins, recently included in the 3rd Watch List of the European Commission as available data indicate that it could pose a significant risk to aquatic species. As yet, the number of studies explicitly assessing the impact of this fungicide on terrestrial and aquatic species is extremely low, and the toxic effects of dimoxystrobin on fish have not been reported. Here we investigate for the first time the alterations induced by two environmentally relevant and very low concentrations of dimoxystrobin (6.56 and 13.13 μg/L) in the fish gills. morphological, morphometric, ultrastructural, and functional alterations have been evaluated using zebrafish as a model species. We demonstrated that even short-term exposure (96 h) to dimoxystrobin alters fish gills reducing the surface available for gas exchange and inducing severe alterations encompassing three reaction patterns: circulatory disturbance and both regressive and progressive changes. Furthermore, we revealed that this fungicide impairs the expression of key enzymes involved in osmotic and acid-base regulation (Na⁺/K⁺-ATPase and AQP3) and the defensive response against oxidative stress (SOD and CAT). The information presented here highlights the importance of combining data from different analytical methods for evaluating the toxic potential of currently used and new agrochemical compounds. Our results will also contribute to the discussion on the suitability of mandatory ecotoxicological tests on vertebrates before the introduction on the market of new compounds.

Molecular and Biochemical Evidence of the Toxic Effects of Terbuthylazine and Malathion in Zebrafish

Our research sought to determine the molecular and biochemical effects of environmentally relevant exposure to commonly used chloro-s-triazine herbicide terbuthylazine and organophosphate insecticide malathion on zebrafish. To this aim, mature zebrafish were exposed to 2 and 30 µg L−1 terbuthylazine and 5 and 50 µg L−1 malathion alone and in combination for 14 days. Aside from the accumulation of TBARS and protein carbonyls, a decrease in antioxidants and succinate dehydrogenase activity, an increase in oxidized glutathione, and enhanced apoptosis via Caspase-3 and BAX overexpression were observed. Furthermore, terbuthylazine and malathion induced mitochondrial swelling (up to 210% after single exposure and up to 470% after co-exposure) and lactate dehydrogenase leakage (up to 268% after single exposure and up to 570% after co-exposure) in a concentration-dependent manner. Significant upregulation of ubiquitin expression and increased cathepsin D activity were characteristics that appeared only upon terbuthylazine exposure, whereas the induction of IgM was identified as the specific characteristic of malathion toxicity. Meanwhile, no alterations in the zebrafish hypothalamic-pituitary-thyroid axis was observed. Co-exposure increased the adverse effects of individual pesticides on zebrafish. This study should improve the understanding of the mechanisms of pesticide toxicity that lead to fish impairment and biodiversity decline.