Transcriptome-Based Identification of Genes Responding to the Organophosphate Pesticide Phosmet in Danio rerio

Permethrin exposure impacts zebrafish lipid metabolism via the KRAS-PPAR-GLUT signaling pathway, which is mediated by oxidative stress

Permethrin (Per) is a widely used and frequently detected pyrethroid pesticide in agricultural products and the environment. It may pose potential toxicity to non-target organisms. Per has been reported to affect lipid homeostasis, although the mechanism is undefined. This study aims to explore the characteristic transcriptomic profiles and clarify the underlying signaling pathways of Per-induced lipid metabolism disorder in zebrafish liver. The results showed that environmental exposure to Per caused changes in the liver index, histopathology, and oxidative stress in zebrafish. Moreover, transcriptome results showed that Per heavily altered the pathways involved in metabolism, the immune system, and the endocrine system. We conducted a more in-depth analysis of the genes associated with lipid metabolism. Our findings revealed that exposure to Per led to a disruption in lipid metabolism by activating the KRAS-PPAR-GLUT signaling pathways through oxidative stress. The disruption of lipid homeostasis caused by exposure to Per may also contribute to obesity, hepatitis, and other diseases. The results may provide new insights for the risk of Permethrin to aquatic organisms and new horizons for the pathogenesis of hepatotoxicity.

In Vitro, In Vivo, and In Silico Analysis of Pyraclostrobin and Cyprodinil and Their Mixture Reveal New Targets and Signaling Mechanisms

Pyraclostrobin and cyprodinil are broad-spectrum fungicides that are used in crops to control diseases. However, they are excessively used and, as a result, end up in the environment and threaten human health and ecosystems. Hence, knowledge of their mechanisms of action is critical to revealing their environmental fate and negative effects and regulating their use. In the present study, we conducted a comprehensive study to show the adverse effects of pyraclostrobin, cyprodinil, and their mixture using zebrafish larvae and different cell lines. Several end points were investigated, including mortality, development, gene expression, reporter assays, and molecular docking simulations. We found that both compounds and their mixture caused developmental delays and mortality in zebrafish, with a higher effect displayed by pyraclostrobin. Both compounds altered the expression of genes involved in several signaling pathways, including oxidative stress and mitochondrial function, lipid and drug metabolisms, the cell cycle, DNA damage, apoptosis, and inflammation. A noteworthy result of this study is that cyprodinil and the mixture group acted as NFκB activators, while pyraclostrobin demonstrated antagonist activity. The AHR activity was also upregulated by cyprodinil and the mixture group; however, pyraclostrobin did not show any effect. For the first time, we also demonstrated that pyraclostrobin had androgen receptor antagonist activity.

The toxicity assessment of phosmet on development, reproduction, and gene expression in Daphnia magna

The use of pesticides to control pests, weeds, and diseases or to regulate plant growth is indispensable in agricultural production. However, the excessive use of these chemicals has led to significant concern about their potential negative impacts on health and the environment. Phosmet is one such pesticide that is commonly used on plants and animals against cold moth, aphids, mites, suckers, and fruit flies. Here, we investigated the effects of phosmet on a model organism, Daphnia magna using acute and chronic toxicity endpoints such as lethality, mobility, genotoxicity, reproduction, and gene expression. We performed survival experiments in six-well plates at seven different concentrations (0.01, 0.1, 1, 10, 25, 50, 100 μM) as well as the control in three replicates. We observed statistically significant mortality rates at 25 µM and above upon 24 h of exposure, and at 1 µM and above following 48 h of exposure. Genotoxicity analysis, reproduction assay and qPCR analysis were carried out at concentrations of 0.01 and 0.1 μM phosmet as these concentrations did not show any lethality. Comet assay showed that exposure to phosmet resulted in significant DNA damage in the cells. Interestingly, 0.1 μM phosmet produced more offspring per adult compared to the control group indicating a hormetic response. Gene expression profiles demonstrated several genes involved in different physiological pathways, including oxidative stress, detoxification, immune system, hypoxia and iron homeostasis. Taken together, our results indicate that phosmet has negative effects on Daphnia magna in a dose- and time-dependent manner and could also induce lethal and physiological toxicities to other aquatic organisms.

Ni/Co/Carbon nitride derived from ZIF-67 (MOF) nanocomposite: Enhanced light-driven photocatalytic degradation of methylparaben, mechanism & toxicity

A nickel oxide/cobalt/carbon nitride (Ni/Co/CN) nanocomposite synthesized via co-precipitation was used for the degradation of methylparaben (MEP). Various analytical techniques were used to ascertain the structural, optical, and electrochemical characteristics of the synthesized nanocomposite. The unique nature of the compound without any free particles over the CN was established. Photocatalytic degradation studies demonstrated the superiority of 3-Ni/Co/CN over bare NiO, Co/CN, 1-Ni/Co/CN, and 5-Ni/Co/CN. Near complete MEP degradation (100%) was achieved after 120 min of incubation with MEP 75 mg L-1 in acidic medium pH (3) for an initial concentration of 3-Ni/Co/CN (10 mg/100 mL). HPLC-MS/MS analysis was used to elucidate the degradation pathway, and the catalyst was found stable for four subsequent cycles. Hence, our nanocatalyst effectively degraded MEP. Furthermore, microbial, aquatic, and animal studies demonstrated the environmental efficiency of the synthesized nanomaterials.

Toxicity effects of pesticides based on zebrafish (Danio rerio) models: Advances and perspectives

Pesticides inevitably enter aquatic environments, posing potential risks to organisms. The common aquatic model organism, zebrafish (Danio rerio), are widely used to evaluate the toxicity of pesticides. In this review, we searched the Web of Science database for articles published between 2012 and 2022, using the keywords "pesticide", "zebrafish", and "toxicity", retrieving 618 publications. Furthermore, we described the main pathways by which pesticides enter aquatic environments and the fate of their residues in these environments. We systematically reviewed the toxicity effects of pesticides on zebrafish, including developmental toxicity, endocrine-disrupting effects, reproductive toxicity, neurotoxicity, immunotoxicity, and genotoxicity. Importantly, we summarized the latest research progress on the toxicity mechanism of pesticides to zebrafish based on omics technologies, including transcriptomics, metabolomics, and microbiomics. Finally, we discussed future research prospects, focusing on the combined exposure of multiple pollutants including pesticides, the risk of multigenerational exposure to pesticides, and the chronic toxicity of aquatic nanopesticides. This review provides essential data support for ecological risk assessments of pesticides in aquatic environments, and has implications for water management in the context of pesticide pollution.

Transcriptome Profiling of Etridiazole-Exposed Zebrafish (Danio rerio) Embryos Reveals Pathways Associated with Cardiac and Ocular Toxicities

Etridiazole (EDZ) is a thiadiazole-containing fungicide commonly used to control Pythium and Phytophthora spp. Although previous studies have shown that EDZ is teratogenic, the exact molecular mechanisms underlying its toxicity remain unknown. In this study, a zebrafish (Danio rerio; ZF) model was used to explore the molecular pathways associated with EDZ toxicity. The whole transcriptome of ZF embryos exposed to 96 h of EDZ was analyzed, along with developmental abnormalities. EDZ-induced malformations were primarily related to the eyes, heart, and growth of the ZF. Compared to untreated ZF, etridiazole-treated ZF had 2882 differentially expressed genes (DEGs), consisting of 1651 downregulated genes and 1231 upregulated genes. Gene ontology enrichment analysis showed that DEGs were involved in biological processes, such as sensory perception, visual perception, sensory organ development, and visual system development, and showed transmembrane transporter and peptidase regulator activities. Metabolism, phototransduction, aminoacyl-tRNA biosynthesis, MAPK signaling pathway, calcium signaling pathway, and vascular smooth muscle contraction were among the most enriched KEGG pathways. The qPCR analyses of the eight random genes were in good agreement with the transcriptome data. These results suggest several putative mechanisms underlying EDZ-induced developmental deformities in ZF.

Multi-level assessment of the origin, feeding area and organohalogen contamination on salmon from the Baltic Sea

The Atlantic salmon (Salmo salar) population in the Baltic Sea consists of wild and hatchery-reared fish that have been released into the sea to support salmon stocks. During feeding migration, salmon migrate to different parts of the Baltic Sea and are exposed to various biotic and abiotic stressors, such as organohalogen compounds (OHCs). The effects of salmon origin (wild or hatchery-reared), feeding area (Baltic Main Basin, Bothnian Sea, and Gulf of Finland), and OHC concentration on the differences in hepatic proteome of salmon were investigated. Multi-level analysis of the OHC concentration, transcriptome, proteome, and oxidative stress biomarkers measured from the same salmon individuals were performed to find the key variables (origin, feeding area, OHC concentrations, and oxidative stress) that best account for the differences in the transcriptome and proteome between the salmon groups. When comparing wild and hatchery-reared salmon, differences were found in xenobiotic and amino acid metabolism-related pathways. When comparing salmon from different feeding areas, the amino acid and carbohydrate metabolic pathways were notably different. Several proteins found in these pathways are correlated with the concentrations of polychlorinated biphenyls (PCBs). The multi-level analysis also revealed amino acid metabolic pathways in connection with PCBs and oxidative stress variables related to glutathione metabolism. Other pathways found in the multi-level analysis included genetic information processes related to ribosomes, signaling and cellular processes related to the cytoskeleton, and the immune system, which were connected mainly to the concentrations of Polychlorinated biphenyls and Dichlorodiphenyltrichloroethane and their metabolites. These results suggest that the hepatic proteome of salmon in the Baltic Sea, together with the transcriptome, is more affected by the OHC concentrations and oxidative stress of the feeding area than the origin of the salmon.

Multispectroscopic studies of binding interaction of phosmet with bovine hemoglobin

Phosmet is a phthalimide derived broad spectrum organophosphate pesticide which is vastly used across the globe to protect several ornamental or horticulture crops. The toxicity of phosmet is of utmost concern because of its direct effect on the nervous system of the victim after exposure. The mechanism of phosmet toxicity was explored by the interaction with the model blood protein which is hemoglobin. Bovine Hemoglobin (BHb) is a major protein of red blood cells (RBCs) that plays an important role in the exchange of gases for respiration and ensures adequate oxygen supply to tissues for oxygenation. In the current study, the interaction of BHb with phosmet was revealed using various spectroscopic techniques. Circular dichroism (CD) and Fourier transform infrared spectroscopy (FTIR) studies of BHb in the presence of phosmet showed secondary structural changes in the protein post binding, Fluorescence study shows the involvement of the dynamic quenching predominantly, Van't Hoffs thermodynamic study showed negative enthalpy value and free energy change and negative entropy change that revealed the involvement of hydrogen bonding and van der Waal forces predominantly further revealing spontaneous nature of binding interaction. The shift in Ultraviolet-visible spectra also revealed the nature of the interaction. In-silico study finally deduced the involvement of hydrogen bonding and polar interaction. The study inferred the moderate interaction of BHb with phosmet.

Whole-Transcriptome Analysis of Repeated Low-Level Sarin-Exposed Rat Hippocampus and Identification of Cerna Networks to Investigate the Mechanism of Sarin-Induced Cognitive Impairment

Sarin is a potent organophosphorus nerve agent that causes cognitive dysfunction, but its underlying molecular mechanisms are poorly understood. In this study, a rat model of repeated low-level sarin exposure was established using the subcutaneous injection of 0.4 × LD₅₀ for 21 consecutive days. Sarin-exposed rats showed persistent learning and memory impairment and reduced hippocampal dendritic spine density. A whole-transcriptome analysis was applied to study the mechanism of sarin-induced cognitive impairment, and a total of 1035 differentially expressed mRNA (DEmRNA), including 44 DEmiRNA, 305 DElncRNA, and 412 DEcircRNA, were found in the hippocampus of sarin-treated rats. According to Gene Ontology (GO) annotation, Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment, and Protein-Protein Interaction (PPI) analysis, these DERNAs were mainly involved in neuronal synaptic plasticity and were related to the pathogenesis of neurodegenerative diseases. The circRNA/lncRNA-miRNA-mRNA ceRNA network was constructed, in which Circ_Fmn1, miR-741-3p, miR-764-3p, miR-871-3p, KIF1A, PTPN11, SYN1, and MT-CO3 formed one circuit, and Circ_Cacna1c, miR-10b-5p, miR-18a-5p, CACNA1C, PRKCD, and RASGRP1 constituted another circuit. The balance between the two circuits was crucial for maintaining synaptic plasticity and may be the regulatory mechanism by which sarin causes cognitive impairment. Our study reveals the ceRNA regulation mechanism of sarin exposure for the first time and provides new insights into the molecular mechanisms of other organophosphorus toxicants.

Transcriptome Analysis of Thiram-Treated Zebrafish (Danio rerio) Embryos Reveals Disruption of Reproduction Signaling Pathways

Thiram, a dithiocarbamate fungicide, is used for the treatment of various fungal infections affecting crops and ornamentals. However, thiram-associated toxicity has been reported in animals, including fish, and the underlying molecular mechanisms are unclear. Herein, we employed zebrafish (ZF) to gain further insights into thiram toxicity-associated molecular mechanisms. We studied developmental abnormalities and performed whole-transcriptome analysis of ZF embryos exposed to thiram for 96 h. Embryos exposed to 4.0 μg/L thiram exhibited several phenotypic abnormalities, including bradycardia, spinal curvature, hatching arrest, and growth retardation. Whole-transcriptome analysis revealed 1754 differentially expressed genes (DEGs), with 512 upregulated and 1242 downregulated DEGs. The majority of biological processes affected by thiram were metabolic. Kyoto Encyclopedia of Genes and Genomes pathway enrichment analysis yielded terms related to reproduction, such as steroid biosynthesis and steroid hormone biosynthesis. Quantitative real-time polymerase chain reaction validation results were in line with sequencing data for ten DEGs. The study results improve our current understanding of the effects of thiram exposure in ZF.

Developmental Toxic Effects of Thiram on Developing Zebrafish (Danio rerio) Embryos

Thiram, an oxidized dimer of dithiocarbamate, has fungicidal and ectoparasiticidal roles. This study aimed to determine the effects of thiram on the development of zebrafish (ZF) embryos. The developmental toxicity test was performed in accordance with the OECD 236 test guidelines, and ZF embryos were subjected to several thiram concentrations and a DMSO (0.01%) control. Subsequently, embryo mortalities and developmental anomalies were evaluated at different hours post fertilization (hpf). Thiram was highly toxic to ZF, with calculated median lethal concentrations (LC₅₀) of thiram at 48 and 96 h as 13.10 ± 2.17 and 8.87 ± 2.09 μg/L, respectively. Thiram-treated embryos/larvae exhibited a variety of deformities, such as abnormal somites, reduced eye pigment, abnormal tail shape, yolk sac edema, hatching defects, and curved spines, with a median effective concentration (EC₅₀) of 3.88 ± 1.23, 5.04 ± 1.82, 6.23 ± 0.92, 5.24 ± 2.22, 1.39 ± 0.25, and 2.60 ± 0.82 μg/L, respectively. Teratogenic index (TI) values ranged from 1.42 to 6.66 for the scored deformities. At 48 hpf, the average heartbeat of the control group was 177.20 ± 5.63 per minute, while the highest thiram-treated group (40 μg/L) was 99.50 ± 18.12 per minute. In addition, cardiac-related issues, such as pericardial edema and abnormal blood flow, were observed in thiram-treated ZF embryos. Overall, these findings suggest that thiram is teratogenic to ZF.