Effect of Propiconazole on the Lipid Metabolism of Zebrafish Embryos ( Danio rerio)

Lipid metabolism in crocodilians: A field with promising applications in the field of ecotoxicology

In the last years, lipid physiology has become an important research target for systems biology applied to the field of ecotoxicology. Lipids are not only essential components of biological membranes, but also participate in extra and intracellular signaling processes and as signal transducers and amplifiers of regulatory cascades. Particularly in sauropsids, lipids are the main source of energy for reproduction, growth, and embryonic development. In nature, organisms are exposed to different stressors, such as parasites, diseases and environmental contaminants, which interact with lipid signaling and metabolic pathways, disrupting lipid homeostasis. The system biology approach applied to ecotoxicological studies is crucial to evaluate metabolic regulation under environmental stress produced by xenobiotics. In this review, we cover information of molecular mechanisms that contribute to lipid metabolism homeostasis in sauropsids, specifically in crocodilian species. We focus on the role of lipid metabolism as a powerful source of energy and its importance during oocyte maturation, which has been increasingly recognized in many species, but information is still scarce in crocodiles. Finally, we highlight priorities for future research on the influence of environmental stressors on lipid metabolism, their potential effect on the reproductive system and thus on the offspring, and their implications on crocodilians conservation.

Network analysis of toxic endpoints of fungicides in zebrafish

Zebrafish being the best animal model to study, every attempt has been made to decipher the toxic mechanism of every fungicide of usage and interest. It is important to understand the multiple targets of a toxicant to estimate the toxic potential in its totality. A total of 22 fungicides of different classes like amisulbrom, azoxystrobin, carbendazim, carboxin, chlorothalonil, difenoconazole, etridiazole, flusilazole, fluxapyroxad, hexaconazole, kresoxim methyl, mancozeb, myclobutanil, prochloraz, propiconazole, propineb, pyraclostrobin, tebuconazole, thiophanate-methyl, thiram, trifloxystrobin and ziram were reviewed and analyzed for their multiple explored targets in zebrafish. Toxic end points in zebrafish are highly informative when it comes to network analysis. They provide a window into the molecular and cellular pathways that are affected by a certain toxin. This can then be used to gain insights into the underlying mechanisms of toxicity and to draw conclusions on the potential of a particular compound to induce toxicity. This knowledge can then be used to inform decisions about drug development, environmental regulation, and other areas of research. In addition, the use of zebrafish toxic end points can also be used to better understand the effects of environmental pollutants on ecosystems. By understanding the pathways affected by a given toxin, researchers can determine how pollutants may interact with the environment and how this could lead to health or environmental impacts.

Chemoenzymatic Asymmetric Synthesis of Chiral Triazole Fungicide (R)-Tebuconazole in High Optical Purity Mediated by an Epoxide Hydrolase from Rhodotorula paludigensis

Tebuconazole is a chiral triazole fungicide used globally in agriculture as a racemic mixture, but its enantiomers exhibit significant enantioselective dissimilarities in bioactivity and environmental behaviors. The steric hindrance caused by the tert-butyl group makes it a great challenge to synthesize tebuconazole enantiomers. Here, we designed a simple chemoenzymatic approach for the asymmetric synthesis of (R)-tebuconazole, which includes the biocatalytic resolution of racemic epoxy-precursor (2-tert-butyl-2-[2-(4-chlorophenyl)ethyl] oxirane, rac-1a) by Escherichia coli/Rpeh whole cells expressed epoxide hydrolase from Rhodotorula paludigensis (RpEH), followed by a one-step chemocatalytic synthesis of (R)-tebuconazole. It was observed that (S)-1a was preferentially hydrolyzed by E. coli/Rpeh, whereas (R)-1a was retained with a specific activity of 103.8 U/g wet cells and a moderate enantiomeric ratio (E value) of 13.4, which was remarkably improved to 43.8 after optimizing the reaction conditions. Additionally, a gram-scale resolution of 200 mM rac-1a was performed using 150 mg/mL E. coli/Rpeh wet cells, resulting in the retention of (R)-1a in a 97.0% ees, a 42.5% yields, and a 40.5 g/L/d space-time yield. Subsequently, the synthesis of highly optical purity (R)-tebuconazole (>99% ee) was easily achieved through the chemocatalytic ring-opening of the epoxy-precursor (R)-1a with 1,2,4-triazole. To elucidate insight into the enantioselectivity, molecular docking simulations revealed that the unique L-shaped substrate-binding pocket of RpEH plays a crucial role in the enantioselective recognition of bulky 2,2-disubstituted oxirane 1a.

Metabolic disturbance of short- and medium-chain chlorinated paraffins to zebrafish larva

Chlorinated paraffins (CPs) are widely produced chemicals. Short-chain CPs (SCCPs) and medium-chain CPs (MCCPs) were listed as Persistent Organic Pollutants (POPs) and candidate POPs under the Stockholm Convention, respectively. The present study explored the developmental toxicity and metabolic disruption caused by SCCPs and MCCPs in zebrafish (Danio rerio) larvae. CPs exposure at environmentally relevant levels caused no obvious phenotypic changes with zebrafish larvae except that the body length shortening was observed after exposure to CPs at 1-200 μg/L for 7 day post fertilization. A further metabolomic approach was conducted to explore the early biological responses of developmental toxicity induced by CPs at low dose (1, 5, and 10 μg/L). The results of metabolic disorder, pathway analysis and chronic values indicated that, compared with SCCPs, MCCPs exhibited more risks to zebrafish larvae at low doses. Lipid metabolism was markedly affected in SCCPs exposure group, whereas MCCPs primarily disturbed lipid metabolism, amino acid, and nucleotide metabolisms. Compare with SCCPs, the relatively higher lipid solubility, protein affinity and metabolic rate of MCCPs can probably explain why MCCP-mediated metabolic disruption was significantly higher than that of SCCP. Notably, SCCPs and MCCPs have the same potential to cause cancer, but no evidence indicates the mutagenicity. In summary, our study provides insight into the potential adverse outcome for SCCP and MCCP at low doses.

Antioxidant enzyme activity and pathophysiological consequences in the sludge worm Tubifex tubifex under acute and sub-lethal exposures to the fungicide Tilt ®

This study aimed to evaluate the effects of propiconazole on the tubificid segmented worm, Tubifex tubifex. The animals were exposed to various concentrations of propiconazole for 96 h to assess the acute effect of this fungicide and for subacute level animals were exposed for 14 days with 10% and 20% of the 96 h LC50 value (0.211 and 0.422 mg/l, respectively). The 96 h LC50 value was determined to be 2.110 mg/l, and sublethal propiconazole concentrations caused significant changes in the oxidative stress enzymes. When compared to control organisms, superoxide dismutase (SOD) and catalase (CAT) activity first decreases and then significantly increases on days 7 and 14. However, GST activity decreases and MDA concentration rises in a concentration- and time-dependent manner throughout the exposure period. In addition, the impacts of propiconazole on Tubifex tubifex were characterized and depicted using a correlation matrix and an integrated biomarker response (IBR) assessment. These findings suggest that exposure to this fungicide distorts the survivability and behavioral response in Tubifex tubifex at the acute level. In addition, it modulates changes in oxidative stress enzymes at the sublethal level. Furthermore, the species sensitivity distribution curve indicates that this tubificid worm has a high risk of survival in the presence of the fungicide propiconazole in aquatic ecosystems.

BDE-209-induced genotoxicity, intestinal damage and intestinal microbiota dysbiosis in zebrafish (Danio Rerio)

The environmental presence of polybrominated diphenyl ethers (PBDEs) is ubiquitous due to their wide use as brominated flame retardants in industrial products. As a common congener of PBDEs, decabromodiphenyl ether (BDE-209) can pose a health risk to animals as well as humans. However, to date, few studies have explored BDE-209's toxic effects on the intestinal tract, and its relevant mechanism of toxicity has not been elucidated. In this study, adult male zebrafish were exposed to BDE-209 at 6 μg/L, 60 μg/L and 600 μg/L for 28 days, and intestinal tissue and microbial samples were collected for analysis to reveal the underlying toxic mechanisms. Transcriptome sequencing results demonstrated a dose-dependent pattern of substantial gene differential expression in the group exposed to BDE-209, and the differentially expressed genes were mainly concentrated in pathways related to protein synthesis and processing, redox reaction, and steroid and lipid metabolism. In addition, BDE-209 exposure caused damage to intestinal structure and barrier function, and promoted intestinal oxidative stress, inflammatory response, apoptosis and steroid and lipid metabolism disorders. Mechanistically, BDE-209 induced intestinal inflammation by increasing the levels of TNF-α and IL-1β and activating the NFκB signaling pathway, and might induce apoptosis through the p53-Bax/Bcl2-Caspase3 pathway. BDE-209 also significantly inhibited the gene expression of rate-limiting enzymes such as Sqle and 3βhsd (p < 0.05) to inhibit cholesterol synthesis. In addition, BDE-209 induced lipid metabolism disorders through the mTOR/PPARγ/RXRα pathway. 16S rRNA sequencing results showed that BDE-209 stress reduced the richness and diversity of intestinal microbiota, and reduced the abundance of probiotics (e.g., Bifidobacterium and Faecalibacterium). Overall, the results of this study help to clarify the intestinal response mechanism of BDE-209 exposure, and provide a basis for evaluating the health risks of BDE-209 in animals.

Medicine designed to combat diseases of affluence affects the early development of fish. How do plastic microparticles contribute?

The incidence of diseases of affluence, such as diabetes mellitus, cardiovascular diseases, high blood pressure, and high cholesterol has been reported to rise. Consequently, the concentrations of residues of drugs designed to treat these diseases have been rising in water bodies. Moreover, the toxicity of these pharmaceuticals towards fish and other non-target organisms can be even enhanced by microplastic particles that are reportedly present in surface water. Therefore, the aim of this study was to describe the effects of three highly prescribed drugs, in particular metoprolol, enalapril, and metformin on fish early-life stages. Also, it was hypothesized that polystyrene microparticles will increase the toxicity of metoprolol to fish early-life stages. Embryonal acute toxicity tests on Danio rerio and Cyprinus carpio were carried out in order to describe the possible toxic effects of metoprolol, enalapril, and metformin. Also, the acute toxicity of polystyrene microparticles and the combination of metoprolol with polystyrene microparticles were tested on D. rerio embryos. Additionally, a 31-day long embryo-larval subchronic toxicity test was carried out with C. carpio in order to describe the long-term effects of low concentrations of metoprolol. The results of the study show that both metoprolol and enalapril have the potential to disrupt the early development of the heart in the embryonal stages of fish. Also, enalapril and metformin together with polystyrene microparticles seem to possibly disrupt the reproduction cycle and act as endocrine disruptors. Both pure polystyrene microparticles and the combination of them with metoprolol affect inflammatory processes in organisms. Additionally, metformin alters several metabolism pathways in fish early-life stages. The results of the study bring new evidence that even low, environmentally-relevant concentrations of pharmaceuticals have the potential to disrupt the early development of fish, particularly on a molecular level.

Comprehensive Stereoselectivity Assessment of Toxicokinetics, Tissue Distribution, Cytotoxicity, and Environmental Fate of Chiral Pesticide Propiconazole

Propiconazole (PRO) has been widely used in the treatment of fungal infection in fruits, vegetables, cereals, and seeds. In this study, a newly established chiral liquid chromatography tandem mass spectrometry method was applied to the systemic stereoselectivity evaluation of PRO enantiomers, including toxicokinetics, tissue distributions, cytotoxicity, accumulation, and degradation. Our results showed that both trans (+)-2S,4S-PRO and cis (-)-2S,4R-PRO had lower Cmax and AUC0-∞ and higher CLz/F values in plasma and lower accumulation concentrations in the liver, heart, and brain. In cytotoxic assays, cis (-)-2S,4R-PRO exhibited the lowest cytotoxicity in PC12 neuronal, N9 microglia, SH-SY5Y neuroblastoma, and MRC5 lung fibroblast cell lines. Moreover, the Eisenia fetida incubation experiment revealed that the accumulations of both trans (+)-2S,4S-PRO and cis (-)-2S,4R-PRO were higher than those of their antipodes in E. fetida. In summary, our findings first suggested that the application of cis (-)-2S,4R-PRO for agriculture would hugely reduce the environmental risk.

Vitamin D modulates disordered lipid metabolism in zebrafish (Danio rerio) liver caused by exposure to polystyrene nanoplastics

In this study, zebrafish (Danio rerio) were exposed to polystyrene nanoplastics (PS-NPs, 80 nm) at 0, 15, or 150 μg/L for 21 days and supplied with a low or high vitamin D (VD) diet (280 or 2800 IU/kg, respectively, indicated by - or +) to determine whether and how VD can regulate lipid metabolism disorder induced by PS-NPs. Six groups were created according to the PS-NP concentration and VD diet status: 0-, 0+, 15-, 15+,150-, and 150 +. Transmission electron microscopy showed that PS-NPs accumulated in the livers of zebrafish, which led to large numbers of vacuoles and lipid droplets in liver cell matrices; this accumulation was most prominent in the 150- group, wherein the number of lipid droplets increased significantly by 136.36%. However, the number of lipid droplets decreased significantly by 76.92% in the 150+ group compared with the 150- group. An examination of additional biochemical indicators showed that the high VD diet partially reversed the increases in the triglyceride and total cholesterol contents induced by PS-NPs (e.g., triglycerides decreased by 58.52% in the 150+ group, and total cholesterol decreased by 44.64% in the 15+ group), and regulated lipid metabolism disorder mainly by inhibiting lipid biosynthesis. Untargeted lipidomics analysis showed that exposure to PS-NPs was associated mainly with changes in the lipid molecular content related to cell membrane function and lipid biosynthesis and that the high VD diet reduced the content of lipid molecules related to lipid biosynthesis, effectively alleviating cell membrane damage and lipid accumulation. These findings highlight the potential of VD to alleviate lipid metabolism disorder caused by PS-NP exposure, thereby providing new insights into how the toxic effects of NPs on aquatic organisms could be reduced.

Metabolic pathway of tebuconazole by soil fungus Cunninghamella elegans ATCC36112

Tebuconazole is the most widely used fungicide in agriculture. Due to its long half-life, tebuconazole residues can be found in the environment media such as in soil and water bodies. Here, the metabolic pathway of tebuconazole was studied in Cunninghamella elegans (C. elegans). Approximately 98% of tebuconazole was degraded within 7 days, accompanied by the accumulation of five metabolites. The structures of the metabolites were completely or tentatively identified by gas chromatography-mass spectrometry (GC-MS) and ultra-high performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS). To identify representative oxidative enzymes that may be involved in the metabolic process, treatment with piperonyl butoxide (PB) and methimazole (MZ) was performed. PB had a strong inhibitory effect on the metabolic reactions, while MZ had a weak inhibitory effect. The results suggest that cytochrome P450 (CYP) and flavin-dependent monooxygenase are involved in the metabolism of tebuconazole. Based on the results, we propose a metabolic pathway for the fungal metabolism of tebuconazole. Data are of interest to gain insight into the toxicological effects of tebuconazole and for tebuconazole bioremediation.

PFOS-induced dyslipidemia and impaired cholinergic neurotransmission in developing zebrafish: Insight into its mechanisms

Perfluorooctane sulfonate (PFOS) is a persistent organic pollutant that has been widely detected in the environment and is known to accumulate in organisms, including humans. The study investigated dose-dependent mortality, hatching rates, malformations, lipid accumulation, lipid metabolism alterations, and impacts on cholinergic neurotransmission. Increasing PFOS concentration led to higher mortality, hindered hatching, and caused concentration-dependent malformations, indicating severe abnormalities in developing zebrafish. The results also demonstrated that PFOS exposure led to a significant increase in total lipids, triglycerides, total cholesterol, and LDL in a concentration-dependent manner, while HDL cholesterol levels were significantly decreased. Additionally, PFOS exposure led to a significant decrease in glucose levels. The study identified TGs, TCHO, and glucose as the most sensitive biomarkers in assessing lipid metabolism alterations. The study also revealed altered expression of genes involved in lipid metabolism, including upregulation of fasn, acaca, and hmgcr and downregulation of ldlr, pparα, and abca1, as well as decreased lipoprotein lipase (LPL) and increased fatty acid synthase (FAS) activity,suggesting an impact on fatty acid synthesis, cholesterol uptake, and lipid transport. Additionally, PFOS exposure led to impaired cholinergic neurotransmission, evidenced by a concentration-dependent inhibition of acetylcholinesterase activity, altered gene expressions related to neural development and function, and reduced Na+/K+-ATPase activity. STRING network analysis highlighted two distinct gene clusters related to lipid metabolism and cholinergic neurotransmission, with potential interactions through the pparα-creb1 pathway. Overall, this study provide important insights into the potential health risks associated with PFOS exposure, including dyslipidemia, cardiovascular disease, impaired glucose metabolism, and neurotoxicity. Further research is needed to fully elucidate the underlying mechanisms and potential long-term effects of PFOS exposure.

Uptake of Nanoplastic particles by zebrafish embryos triggers the macrophage response at early developmental stage

Plastic pollution continues to erupt as a global ecological concern. As plastic debris is degraded into nanoscale and microscale particles via biodegradation, UV-irradiation, and mechanical processes, nanoplastic pollution arises as a threat to virtually every biological and ecological system on the planet. In this study, zebrafish (Danio rerio) embryos were exposed to fluorescently labeled plastic particles at nanoscales (30 nm and 100 nm). The uptake of both the nanoplastic particles (NPs) was found to exponentially increase with incubation time. Penetration of NPs through the natural barrier of the zebrafish embryos, the chorion, was observed prior to the hatching of the embryo. As a result, the NPs were found to accumulate on the body surface as well as inside the body of the zebrafish. The invasion of NPs into zebrafish embryos induced the upregulation of several stress and immune response genes including interleukins (il6 and il1b), cytochrome P450 (cyp1a and cyp51), and reactive oxygen species (ROS) removal protein-encoding genes (sod and cat). This suggested the initiation of ROS generation and removal as well as the activation of the immune response of zebrafish embryos. Colocalization of macrophages and NPs in zebrafish embryos indicated the involvement of macrophage response to the NP invasion at the early developmental stage of zebrafish.

Neurobehavioral effects of fungicides in zebrafish: a systematic review and meta-analysis

Pesticides are widely used in global agriculture to achieve high productivity levels. Among them, fungicides are specifically designed to inhibit fungal growth in crops and seeds. However, their application often results in environmental contamination, as these chemicals can persistently be detected in surface waters. This poses a potential threat to non-target organisms, including humans, that inhabit the affected ecosystems. In toxicologic research, the zebrafish (Danio rerio) is the most commonly used fish species to assess the potential effects of fungicide exposure, and numerous and sometimes conflicting findings have been reported. To address this, we conducted a systematic review and meta-analysis focusing on the neurobehavioral effects of fungicides in zebrafish. Our search encompassed three databases (PubMed, Scopus, and Web of Science), and the screening process followed predefined inclusion/exclusion criteria. We extracted qualitative and quantitative data, as well as assessed reporting quality, from 60 included studies. Meta-analyses were performed for the outcomes of distance traveled in larvae and adults and spontaneous movements in embryos. The results revealed a significant overall effect of fungicide exposure on distance, with a lower distance traveled in the exposed versus control group. No significant effect was observed for spontaneous movements. The overall heterogeneity was high for distance and moderate for spontaneous movements. The poor reporting practices in the field hindered a critical evaluation of the studies. Nevertheless, a sensitivity analysis did not identify any studies skewing the meta-analyses. This review underscores the necessity for better-designed and reported experiments in this field.

Triazole fungicides exert neural differentiation alteration through H3K27me3 modifications: In vitro and in silico study

Considering that humans are unavoidably exposed to triazole fungicides through the esophagus, respiratory tract, and skin contact, revealing the developmental toxicity of triazole fungicides is vital for health risk assessment. This study aimed to screen and discriminate neural developmental disorder chemicals in commonly used triazole fungicides, and explore the underlying harmful impacts on neurogenesis associated with histone modification abnormality in mouse embryonic stem cells (mESCs). The triploblastic and neural differentiation models were constructed based on mESCs to expose six typical triazole fungicides (myclobutanil, tebuconazole, hexaconazole, propiconazole, difenoconazole, and flusilazole). The result demonstrated that although no cytotoxicity was observed, different triazole fungicides exhibited varying degrees of alterations in neural differentiation, including increased ectodermal differentiation, promoted neurogenesis, increased intracellular calcium ion levels, and disturbance of neurotransmitters. Molecular docking, cluster analysis, and multiple linear regressions demonstrated that the binding affinities between triazole fungicides and the Kdm6b-ligand binding domain were the dominant determinants of the neurodevelopmental response. This partially resulted in the reduced enrichment of H3K27me3 at the promoter region of the serotonin receptor 2 C gene, finally leading to disturbed neural differentiation. The data suggested potential adverse outcomes of triazole fungicides on embryonic neurogenesis even under sublethal doses through interfering histone modification, providing substantial evidence on the safety control of fungicides.

Zebrafish as model organisms for toxicological evaluations in the field of food science

Food safety has long been an area of concern. The selection of stable and efficient model organisms is particularly important for food toxicology studies. Zebrafish (Danio rerio) are small model vertebrates, and 70% of human genes have at least one zebrafish ortholog. Zebrafish have advantages as model organisms due to their short life cycle, strong reproductive ability, easy rearing, and low cost. Zebrafish embryos have the advantage of being sensitive to the breeding environment and thus have been used as biosensors. Zebrafish and their embryos have been widely used for food toxicology assessments. This review provides a systematic and comprehensive summary of food toxicology studies using zebrafish as model organisms. First, we briefly introduce the multidimensional mechanisms and structure-activity relationship studies of food toxicological assessment. Second, we categorize these studies according to eight types of hazards in foods, including mycotoxins, pesticides, antibiotics, heavy metals, endocrine disruptors, food additives, nanoparticles, and other food-related ingredients. Finally, we list the applications of zebrafish in food toxicology studies in line with future research prospects, aiming to provide a valuable reference for researchers in the field of food science.

Enantioselective effects of paclobutrazol and its enantiomers on glycolipid metabolism in zebrafish (Danio rerio)

Paclobutrazol is a plant growth inhibitor widely used in agricultural production. However, toxicology studies of paclobutrazol enantiomers towards aquatic organisms are limited. Herein, effects of paclobutrazol and its two enantiomers (2R, 3R; 2S, 3S) on glycolipid metabolism of zebrafish have been systemically explored at the concentration of 10 mg/L through biochemical analyses, LC-MS/MS, molecular dynamics simulation, and gene expression. In all treatments, the contents of glucose, citric acid and lactate significantly were increased while the glycogen and pyruvate contents were decreased, in which (2R, 3R)-paclobutrazol exhibited a greater effect than the (2S, 3S)-enantiomer (P < 0.05). Then, activities of hexokinase and lactate dehydrogenase in (2R, 3R)-paclobutrazol treatment were 0.74- and 1.18-fold higher than (2S, 3S)-enantiomer treatment, respectively (P < 0.001), and the results of molecular dynamics simulation revealed that the binding free energy of hexokinase 1 to (2R, 3R)-paclobutrazol was higher than that to the antipode. Moreover, lipids including triglycerides, total cholesterol, fatty acids, bile acids and glycerophospholipids in zebrafish were strikingly affected after paclobutrazol exposure. The (2R, 3R)-paclobutrazol-treated group showed the most obvious changes, indicating that it possessed much stronger disruption ability on the lipid metabolism of zebrafish. Furthermore, qRT-PCR analysis results revealed that (2R, 3R)-enantiomer significantly impacted expressions of glycolipid metabolism-related genes (hk1, g6pc, pck1, pk, aco, cebpa, cyp51, fasn and ppara) in zebrafish than (2S, 3S)-enantiomer (P < 0.05). Briefly, this study provides new evidences for the toxicity of paclobutrazol to aquatic organisms and the potential risk to human health at the chiral level.

Enantioselectivity effects of energy metabolism in honeybees (Apis mellifera) by triticonazole

The heavy use of agrochemicals is considered a major factor contributing to the decline in wild honeybee populations. Development of low-toxicity enantiomers of chiral fungicides is the key to reducing the potential threats to honeybees. In this study, we evaluated the enantioselective toxic effects of triticonazole (TRZ) on honeybees and its molecular mechanisms. The results showed that after long-term exposure to TRZ, the content of thoracic ATP decreased significantly, by 41 % in R-TRZ treatments and by 46 % in S-TRZ treatments. Furthermore, the transcriptomic results indicated that S-TRZ and R-TRZ significantly altered the expression of 584 genes and 332 genes, respectively. Pathway analysis indicated that R- and S-TRZ could affect different genes expressed in GO terms and metabolic pathways, especially the transport GO terms (GO: 0006810) and pathways of alanine, aspartate and glutamate metabolism, drug metabolism - cytochrome P450, and pentose phosphate. Additionally, S-TRZ had a more pronounced effect on honeybee energy metabolism, disrupting a greater number of genes involved in the TCA cycle and glycolysis/glycogenesis, exerting a stronger effect on energy metabolic pathways, including nitrogen metabolism, sulfur metabolism, and oxidative phosphorylation. In summary, we recommend reducing the proportion of S-TRZ in racemate to minimize the threat to the survival of honeybees and protect the diversity of economic insects.

Hormesis effects of sulfoxaflor on Aphis gossypii feeding, growth, reproduction behaviour and the related mechanisms

Sulfoxaflor, an important alternative insecticide in integrated pest management (IPM) strategies, can effectively control sap-feeding insect pests such as Aphis gossypii. Although the side effects of sulfoxaflor have recently attracted widespread attention, its toxicological characteristics and mechanisms are still largely undefined. Therefore, the biological characteristics, life table and feeding behaviour of A. gossypii were studied to evaluate the hormesis effect of sulfoxaflor. Then, the potential mechanisms of induced fecundity associated with the vitellogenin (Ag. Vg) and vitellogenin receptor (Ag. VgR) genes were investigated. Although the LC₁₀ and LC₃₀ concentrations of sulfoxaflor significantly reduced the fecundity and net reproduction rate (R₀) of the directly exposed sulfoxaflor-resistant and susceptible aphids, hormesis effects on fecundity and R₀ were observed in the F₁ generation of Sus A. gossypii when the parental generation was exposed to the LC₁₀ of sulfoxaflor. Moreover, the hormesis effects of sulfoxaflor on phloem feeding were observed in both A. gossypii strains. Additionally, enhanced expression levels and protein content of Ag. Vg and Ag. VgR were observed in progeny generations when F₀ was subjected to the trans- and multigenerational sublethal sulfoxaflor exposure. Therefore, sulfoxaflor-induced resurgence might occur in A. gossypii after exposure to sublethal concentrations. Our study could contribute to a comprehensive risk assessment and provide convincing reference to optimize sulfoxaflor in IPM strategies.

Developmental Neurotoxicity of Difenoconazole in Zebrafish Embryos

Difenoconazole is a type of triazole fungicide that is widely used in the treatment of plant diseases. Triazole fungicides have been shown in several studies to impair the development of the nervous system in zebrafish embryos. There is still little known about difenoconazole-induced neurotoxicity in fish. In this study, zebrafish embryos were exposed to 0.25, 0.5, and 1 mg/L of difenoconazole solution until 120 h post-fertilization (hpf). The difenoconazole-exposed groups showed concentration-dependent inhibitory tendencies in heart rate and body length. Malformation rate and spontaneous movement of zebrafish embryos increased, and the locomotor activity decreased in the highest exposure group. The content of dopamine and acetylcholine was reduced significantly in difenoconazole treatment groups. The activity of acetylcholinesterase (AChE) was also increased after treatment with difenoconazole. Furthermore, the expression of genes involved in neurodevelopment was remarkably altered, which corresponded with the alterations of neurotransmitter content and AChE activity. These results indicated that difenoconazole might affect the development of the nervous system through influencing neurotransmitter levels, enzyme activity, and the expression of neural-related genes, ultimately leading to abnormal locomotor activity in the early stages of zebrafish.

The Emerging Prevalence of Obesity within Families in Europe and its Associations with Family Socio-Demographic Characteristics and Lifestyle Factors; A Cross-Sectional Analysis of Baseline Data from the Feel4Diabetes Study

The Feel4Diabetes study is a type 2 diabetes prevention program that recruited 12,193 children [age: 8.20 (±1.01) years] and their parents from six European countries. The current work used pre-intervention data collected from 9576 children-parents pairs, to develop a novel family obesity variable and to examine its associations with family sociodemographic and lifestyle characteristics. Family obesity, defined as the presence of obesity in at least two family members, had a prevalence of 6.6%. Countries under austerity measures (Greece and Spain) displayed higher prevalence (7.6%), compared to low-income (Bulgaria and Hungary: 7%) and high-income countries (Belgium and Finland: 4.5%). Family obesity odds were significantly lower when mothers (OR: 0.42 [95% CI: 0.32, 0.55]) or fathers (0.72 [95% CI: 0.57, 0.92]) had higher education, mothers were fully (0.67 [95% CI: 0.56, 0.81]) or partially employed (0.60 [95% CI: 0.45, 0.81]), families consumed breakfast more often (0.94 [95% CI: 0.91 0.96]), more portions of vegetables (0.90 [95% CI: 0.86, 0.95]), fruits (0.96 [95% CI: 0.92, 0.99]) and wholegrain cereals (0.72 [95% CI: 0.62, 0.83]), and for more physically active families (0.96 [95% CI: 0.93, 0.98]). Family obesity odds increased when mothers were older (1.50 [95% CI: 1.18, 1.91]), with the consumption of savoury snacks (1.11 [95% CI: 1.05, 1.17]), and increased screen time (1.05 [95% CI: 1.01, 1.09]). Clinicians should familiarise themselves with the risk factors for family obesity and choose interventions that target the whole family. Future research should explore the causal basis of the reported associations to facilitate devising tailored family-based interventions for obesity prevention.

Early- and whole-life exposures to florfenicol disrupts lipid metabolism and induces obesogenic effects in zebrafish (Danio rerio)

Florfenicol (FF), a widely used veterinary antibiotic, has been frequently detected in both aquatic environments and human body fluids. As a result, there is a growing concern on its health risks. Previous studies have revealed various toxicities of FF on animals, while there are relatively limited researches on its metabolic toxicity. Herein, by employing zebrafish as an in vivo model, endpoints at multiple levels of biological organization were measured to investigate the metabolic toxicity, especially disturbances on lipid metabolism, of this emerging pollutant. Our results indicated that early-life exposure (from 2 h past fertilization (hpf) to 15 days past fertilization (dpf)) to FF significantly increased body mass index (BMI) values, staining areas of visceral lipids, and triacylglycerol (TAG) and total cholesterol (TC) contents of larvae. Further, by analyzing expression patterns of genes encoding key proteins regulating lipid metabolism, our data suggested that promoted intestinal absorption and hepatic de novo synthesis of lipids, suppressed TAG decomposition, and inhibited FFA oxidation all contributed to TAG accumulation in larvae. Following whole-life exposure (from 2 hpf to 120 dpf), BMI values, TAG and TC contents all increased significantly in males, and significant increases of hepatic TAG levels were also observed in females. Moreover, FF exposure interfered with lipid homeostasis of males and females in a gender-specific pattern. Our study revealed the obesogenic effects of FF at environmentally relevant concentrations (1, 10, and 100 μg/L) and therefore will benefit assessment of its health risks. Additionally, our results showed that FF exposure caused a more pronounced obesogenic effect in zebrafish larvae than adults, as suggested by significant increases of all endpoints at individual, tissular, and molecular levels in larvae. Therefore, our study also advances the application of zebrafish larval model in assessing metabolic toxicity of chemicals, due to the higher susceptibility of larvae than adults.

Toxicity effects of chlorantraniliprole in zebrafish (Danio rerio) involving in liver function and metabolic phenotype

Chlorantraniliprole (CAP), a representative bisamide insecticide, is widely used in rice fields around the world, posing potential toxicity risks to aquatic organisms. In this study, we examined the effects of exposure to CAP on growth and metabolic phenotype of zebrafish (Danio rerio) and oxidative stress and apoptosis in the liver of zebrafish (Danio rerio). First, we identified that CAP had a low bioaccumulation in zebrafish. Subsequently, growth phenotype analysis revealed that CAP could significantly increase liver weight and liver index in zebrafish. In addition, we found that CAP exposure could cause significant changes in indicators of oxidative stress, resulting in a significant increase in the content of malondialdehyde (MDA), causing oxidative stress in the liver of zebrafish. Meanwhile, the expression levels of apoptosis-related genes were also significantly changed and apoptosis was promoted in the liver of zebrafish with CAP exposure. Importantly, the results of metabolomics analysis shown that CAP exposure could significantly disrupt the metabolic phenotype of zebrafish, interfering with multiple metabolic pathways, mainly including valine, leucine and isoleucine biosynthesis and degradation, alanine, aspartate and glutamate metabolism and d-glutamine and D-glutamate metabolism. Last but not least, correlation analysis identified strong links between changes in liver function involving oxidative stress and apoptosis and changes in metabolic phenotype of zebrafish following CAP exposure. In brief, these results indicate that potential environmental risks of CAP to aquatic organisms should receive more attention.

Parental exposure to propiconazole at environmentally relevant concentrations induces thyroid and metabolism disruption in zebrafish (Danio rerio) offspring: An in vivo, in silico and in vitro study

Propiconazole is used against fungal growth in agriculture and is released into the environment, but is a potential health threat to aquatic organisms. Propiconazole induces a generational effect on zebrafish, although the toxic mechanisms involved have not been described. The aim of this study was to investigate the potential mechanisms of abnormal offspring development after propiconazole exposure in zebrafish parents. Zebrafish were exposed to propiconazole at environmentally realistic concentrations (0.1, 5, and 250 μg/L) for 100 days and their offspring were grown in control solution for further study. Heart rate, hatching rate, and body length of hatched offspring were reduced. An increase in triiodothyronine (T₃) content and the T₃/T₄ (tetraiodothyronine) ratio was observed, indicating disruption of thyroid hormones. Increased protein level of transthyretin (TTR) in vivo was consistent with the in silico molecular docking results and T₄ competitive binding in vitro assay, suggests higher binding affinity between propiconazole and TTR, more than with T₄. Increased expression of genes related to the hypothalamus-pituitary-thyroid (HPT) axis and altered metabolite levels may have affected offspring development. These findings emphasizes that propiconazole, even on indirect exposure, represents health and environmental risk that should not be ignored.

Effect of propiconazole on plastic film microplastic degradation: Focusing on the change in microplastic morphology and heavy metal distribution

With the rapid increase in the use of plastic films, microplastic (MP) pollution in agricultural soils has become a global environmental problem. Propiconazole is widely used in agriculture and horticulture; however, its role in plastic film degradation remains elusive. Butylene adipate-co-terephthalate (PBAT) and polyethylene (PE) films were used to analyze the effects of propiconazole on plastic film and MP degradation. We identified the surface morphologies of PBAT and PE at different propiconazole concentrations and soil pH values, as well as the adsorption and release characteristics of heavy metals during the degradation process via scanning electron microscopy, Fourier transform infrared spectroscopy and inductively coupled plasma mass spectrometry. Propiconazole accelerated the degradation of MPs, adsorption of heavy metals (Ni and Zn), and release of Sn at low concentrations (≤40 mg/kg); however, these effects were evidently absent at a high concentration (120 mg/kg). Furthermore, MPs were more prone to degradation in acidic or alkaline soils than in neutral soil when they coexisted with propiconazole. Hence, we suggest that PBAT and PE plastic films may not be suitable for application in acidic and alkaline soils with propiconazole, because of shorter rupture time and more heavy metal adsorption. PBAT degraded faster, absorbed and released more heavy metals than PE. Under all tested conditions, the heavy metal contents in MPs gradually approached those in soil, which proves that MPs are carriers of heavy metal pollutants. These results may help in assessing the impact of MPs on soil environments and provide a theoretical basis for the standardized propiconazole and plastic film usage.

Charge-specific adverse effects of polystyrene nanoplastics on zebrafish (Danio rerio) development and behavior

Nanoplastics are being detected with increasing frequency in aquatic environments. Although evidence suggests that nanoplastics can cause overt toxicity to biota across different trophic levels, but there is little understanding of how materials such as differently charged polystyrene nanoplastics (PS-NP) impact fish development and behavior. Following exposure to amino-modified (positive charge) PS-NP, fluorescence accumulation was observed in the zebrafish brain and gastrointestinal tract. Positively charged PS-NP induced stronger developmental toxicity (decreased spontaneous movement, heartbeat, hatching rate, and length) and cell apoptosis in the brain and induced greater neurobehavioral impairment as compared to carboxyl-modified (negative charge) PS-NP. These findings correlated well with fluorescence differences indicating PS-NP presence. Targeted neuro-metabolite analysis by UHPLC-MS/MS reveals that positively charged PS-NP decreased levels of glycine, cysteine, glutathione, and glutamic acid, while the increased levels of spermine, spermidine, and tyramine were induced by negatively charged PS-NP. Positively charged PS-NP interacted with the neurotransmitter receptor N-methyl-D-aspartate receptor 2B (NMDA2B), whereas negatively charged PS-NP impacted the G-protein-coupled receptor 1 (GPR1), each with different binding energies that led to behavioral differences. These findings reveal the charge-specific toxicity of nanoplastics to fish and provide new perspective for understanding PS-NP neurotoxicity that is needed to accurately assess potential environmental and health risks of these emerging contaminants.

Developmental toxicity and neurotoxicity assessment of R-, S-, and RS-propylene glycol enantiomers in zebrafish (Danio rerio) larvae

Propylene glycol (PG) is widely used in the foods, pharmaceuticals, oil industry, animal feed, cosmetics and other industries. Because of the existence of a chiral carbon center, PG forms R (Rectus)- and S (Sinister)-enantiomers. Currently, the toxicity study of its R-, S-enantiomers is still very scarce. In this study, we have assessed the developmental toxicity and neurotoxicity of the R-, S-, and RS-PG enantiomers in zebrafish larvae. We found that exposure to R-, S-, and RS-PG enantiomers did not significantly affect the basic developmental endpoints of embryos or larvae (i.e., embryonic movement, hatching, mortality, malformation, heartbeat, body length), indicating that R-, S-, and RS-PG exposures did not exhibit the basic developmental toxicity in zebrafish larvae. The toxicity of three enantiomers was lower than that of ethanol, and there was no significant difference between them. However, R-, S-, and RS-PG exposures with high doses could significantly change the eye diameter and locomotor activity of larval zebrafish, indicating that R-, S-, and RS-PG enantiomers of high doses could potentially exhibit the neurotoxicity and ocular developmental toxicity in zebrafish larvae. Therefore, the potential neurotoxicity and ocular developmental toxicity of R-, S-, and RS-PG enantiomers for infants and toddlers should be considered.

A comprehensive review of 1,2,4-triazole fungicide toxicity in zebrafish (Danio rerio): A mitochondrial and metabolic perspective

In this critical review, we synthesize data from peer-reviewed literature reporting on triazole fungicide exposures in the zebrafish model. Based on their mode of action in plants (potent inhibitors of ergosterol synthesis), we focused attention on mechanisms related to cellular, lipid, and steroid metabolism. Evidence from several studies reveals that zebrafish exposed to triazoles present with impaired mitochondrial oxidative phosphorylation and oxidative stress, as well as dysregulation of lipid metabolism. Such metabolic disruptions are expected to underscore developmental delays, deformity, and aberrant locomotor activity and behaviors often observed following exposure. We begin by summarizing physiological and behavioral effects observed with triazole fungicide exposure in zebrafish. We then discuss mechanisms that may underlie adverse apical effects, focusing on mitochondrial bioenergetics and metabolism. Using computational approaches, we also identify novel biomarkers of triazole fungicide exposure. Extracting and analyzing data contained in the Comparative Toxicogenomics Database (CTD) revealed that transcriptional signatures responsive to different triazoles are related to metabolism of lipids and lipoproteins, biological oxidations, and fatty acid, triacylglycerol, and ketone body metabolism among other processes. Pathway and sub-network analysis identified several transcripts that are responsive in organisms exposed to triazole fungicides, several of which include lipid-related genes. Knowledge gaps and recommendations for future investigations include; (1) targeted metabolomics for metabolites in glycolysis, Krebs cycle, and the electron transport chain; (2) additional studies conducted at environmentally relevant concentrations to characterize the potential for endocrine disruption, given that studies point to altered cholesterol (precursor for steroid hormones), as well as altered estrogen receptor alpha and thyroid hormone expression; (3) studies into the potential role for lipid peroxidation and oxidation of lipid biomolecules as a mechanism of triazole-induced toxicity, given the strong evidence for oxidative damage in zebrafish following exposure to triazole fungicides.

Developmental toxicity of fenbuconazole in zebrafish: effects on mitochondrial respiration and locomotor behavior

Triazole fungicides are used to control the disease of cereal crops but may also cause adverse effects on non-target organisms. There is a lack of toxicity data for some triazoles such as fenbuconazole in aquatic organisms. This research was conducted to evaluate the toxicity of fenbuconazole at environmentally relevant concentrations with attention on the mitochondria, antioxidant system, and locomotor activity in zebrafish. Zebrafish were exposed to one concentration of 5, 50, 200 or 500ng/L fenbuconazole for 96h. There was no effect on survival nor percentage of fish hatched, but exposure to 200 and 500ng/L fenbuconazole resulted in malformation and hypoactivity in zebrafish. Oxygen consumption rates (OCR) of embryos were measured to determine if the fungicide impaired mitochondrial respiration. Exposure to 500ng/L fenbuconazole reduced basal OCR and oligomycin-induced ATP linked respiration in exposed fish. Fenbuconazole reduced mitochondrial membrane potential and reduced the activities of mitochondrial Complex II and III. Transcript levels of both sdhc and cyc1, each related to Complex II and III, were also altered in expression by fenbuconazole exposure, consistent with mitochondrial dysfunction in embryos. Fenbuconazole activated the antioxidant system, based upon both transcriptional and enzymatic data in zebrafish. Consistent with mitochondrial impairment, molecular docking confirmed a strong binding capacity of the fungicide at the Q_i site of Complex III, revealing this complex is susceptible to fenbuconazole. This study reveals potential toxicity pathways related to fenbuconazole exposure in aquatic organisms; such data can improve risk assessments for triazole fungicides.

New insights into potential estrogen agonistic activity of triazole fungicides and coupled metabolic disturbance

Triazole fungicides are highly effective pesticides widely used in plant protection, which has caused potential hazards to human health and ecological safety. To fully understand their potential hepatotoxicity, we first analyzed the transcriptome profiles in HepG2 cells treated with five triazole fungicides (hexiconazole (HEX), tebuconazole (TEB), propiconazole (PRO), cyproconazole (CYP), and difenoconazole (DIF)), and found that these pesticides remarkably affected estrogen signaling pathways, especially estrogen synthesis. Furthermore, we found that TEB, CYP, PRO and DIF had agonistic activity towards estrogen receptor alpha (ERα) and elucidated the binding mode of triazole ligands with ERα using the reporter gene assay and molecular docking. Four triazole fungicides regulated eight major genes involved in estrogen synthesis (StAR, CYP11A1, 3βHSD2, CYP17, CYP19, CYP3A4, CYP1A2 and SCP2) and stimulated the secretion of 17β-estradiol (E₂). Finally, we assessed possible metabolic outcomes caused by abnormal estrogen synthesis, and found that triazole fungicides affected the metabolism of various macromolecules (such as lipid, amino acid, and carbohydrate) and signal transduction. These findings will provide new insights into endocrine-disrupting effects of triazole fungicides and highlight their potential ecological and health risks.

Antibody Generation and Rapid Immunochromatography Using Time-Resolved Fluorescence Microspheres for Propiconazole: Fungicide Abused as Growth Regulator in Vegetable

Propiconazole (PCZ) is a fungicide popularly used to prevent and control wheat and rice bakanae disease, etc. However, it was recently found to be illegally employed as a plant regulator to induce thick stems and dark green leaves of Brassica campestris, a famous vegetable in Guangdong, South China. Due to a lack of available recognition molecules to the target analyte, it is still a big challenge to establish a rapid surveillance screening method. In this study, a novel chiral hapten was rationally designed, and an artificial immunogen was then prepared for the generation of a specific antibody against propiconazole for the first time. Using the obtained antibody, a highly sensitive time-resolved fluorescence microspheres lateral flow immunochromatographic assay (TRFMs-LFIA) was established with a visual limit of detection of 100 ng/mL and a quantitative limit of detection of 1.92 ng/mL for propiconazole. TRFMs-LFIA also exhibited good recoveries ranging from 78.6% to 110.7% with coefficients of variation below 16%. The analysis of blind real-life samples showed a good agreement with results obtained using HPLC-MS/MS. Therefore, the proposed method could be used as an ideal screening surveillance tool for the detection of propiconazole in vegetables.

Enantioselective toxic effects of mefentrifluconazole in the liver of adult zebrafish (Danio rerio) based on transcription level and metabolomic profile

Mefentrifluconazole, a new type of chiral triazole fungicide, is widely applied to control a variety of fungal diseases in crops. However, the toxicological effects of mefentrifluconazole on aquatic organisms are unknown, especially at the enantiomer level. In the present study, zebrafish were selected as a typical model for mefentrifluconazole enantiomer exposure. Metabolomic and transcription analyses were performed with 0.01 and 0.10 mg/L mefentrifluconazole and its enantiomers (i.e., rac-mfz/(-)-mfz/(+)-mfz) at 28 days. The ¹H nuclear magnetic resonance (NMR)-based metabolomics analysis showed that 9, 10 and 4 metabolites were changed significantly in the rac-mfz, (+)-mfz and (-)-mfz treatment groups compared with the control group, respectively. The differential metabolites were related to energy metabolism, lipid metabolism and amino acid metabolism. The qRT-PCR analysis revealed that the expression of lipid metabolism-, apoptosis- and CYP-related genes in the livers of female zebrafish in rac-mfz and (+)-mfz was 1.61-108.92 times and 2.37-551.34 times higher than that in (-)-mfz, respectively. The results above indicate that exposure to mefentrifluconazole induced enantioselective liver toxicity in zebrafish. Our study underlined the importance of distinguishing different enantiomers, which will contribute to environmental protection.

Tralopyril affects locomotor activity of zebrafish (Danio rerio) by impairing tail muscle tissue, the nervous system, and energy metabolism

Tralopyril (TP), an antifouling biocide, is widely used to prevent heavy biofouling, and can have potential risks to aquatic organisms. In this study, the effect of TP on locomotor activity and related mechanisms were evaluated in zebrafish (Danio rerio) larvae. TP significantly reduced locomotor activity after 168 -h exposure. Adverse modifications in tail muscle tissue, the nervous system, and energy metabolism were also observed in larvae. TP caused thinning of the muscle bundle in the tail of larvae. In conjunction with the metabolomics results, changes in dopamine (DA) and acetylcholine (ACh), acetylcholinesterase (AChE) activity, and the expression of genes involved in neurodevelopment, indicate that TP may disrupt the nervous system in zebrafish larvae. The change in metabolites (e.g., glucose 6-phosphate, cis-Aconitic acid, acetoacetyl-CoA, coenzyme-A and 3-Oxohexanoyl-CoA) involved in carbohydrate and lipid metabolism indicates that TP may disrupt energy metabolism. TP exposure may inhibit the locomotor activity of zebrafish larvae by impairing tail muscle tissue, the nervous system, and energy metabolism.

Photoaging enhanced the adverse effects of polyamide microplastics on the growth, intestinal health, and lipid absorption in developing zebrafish

The safety of microplastics (MPs) and associated health effects has been one of the major concerns worldwide. However, the role of photoaging toward the risk of MPs in water ecosystems remains inconclusive yet. In this study, the size of polyamide (PA, ∼32.50 μm) MPs was obviously decreased after photoaging in water containing fulvic acid (FA) and humic acid (HA) (∼19.75 and ∼24.30 μm, respectively). Nanoplastics were formed (4.65% and 2.03%, respectively) and hydrophilia and colloidal stability was improved due to the formation of oxygen-containing functional groups. FA-aged PA exhibited higher inhibition on body length and weight of developing zebrafish than HA-aged and pristine PA. Photoaged MPs in intestine were more difficult to be depurated by zebrafish, leading to the disappearance of intestinal folding, shedding of more enterocytes, and emaciation of intestinal microvilli. Dietary lipid digestion in larvae was inhibited by aged PA due to oxidative stress-triggered lipid peroxidation and inhibition of lipase activities and bile acids secretion. Exposure of photoaged MPs down-regulated genes (cd36, dgat1a, dgat2, mttp, etc.) associated with triglyceride resynthesis and transportation, resulting in lipid maladsorption and growth inhibition. Our findings highlight the potential negative effects of environmentally aged MPs on diet digestion and nutrient assimilation in fish.

Highly selective monoclonal antibody-based lateral flow immunoassay for visual and sensitive determination of conazole fungicides propiconazole in vegetables

The conazole fungicide propiconazole is frequently found in vegetables although usage is not allowed. To overcome the high-cost and time-consuming labour requirements of instrumental methods, we developed a simple and visual lateral flow immunoassay for the sensitive determination of propiconazole. A hapten was carefully designed to raise a monoclonal antibody against propiconazole. Bal b/c mice were immunised with the hapten-carrier protein conjugate and a specific monoclonal antibody (mAb) was produced. Based on this mAb, a sensitive immunochromatographic strip assay (ICA) was established for rapid screening of propiconazole in vegetable samples. After optimisation of analytical parameters, the ICA strip showed a detection limit of 0.13 ng g-1 and a linear range from 0.5 to 80 ng g-1 using a strip reader. The assay also can be read by the naked eye with a visual limit of detection of 80 ng g-1. The recoveries for spiked vegetable samples by ICA ranged from 85.2% to 114.9%, with a coefficient of variation less than 11.7%. The assay time is within 45 min for a single sample including the sample pre-treatment. For spiked and blind samples, the detection capability of ICA was equivalent to liquid chromatography-mass spectrometry.

Environmentally relevant concentrations of tralopyril affect carbohydrate metabolism and lipid metabolism of zebrafish (Danio rerio) by disrupting mitochondrial function

Tralopyril (TP), an antifouling biocide, is widely used to prevent heavy biofouling, and can have potential risks to aquatic organisms. However, there is little information available on the toxicity of tralopyril to aquatic organisms. In this study, the effect of TP on carbohydrate and lipid metabolism, and related mechanisms were evaluated in zebrafish (Danio rerio) larvae. Adverse modifications in carbohydrate metabolism were observed in larvae: hexokinase (HK) activity, succinate dehydrogenase (SDH) activity, and adenosine triphosphate (ATP) content were significantly decreased; and transcript expression of genes (GK, HK1, and PCK1) was also significantly changed. Changes of TG content, FAS activity and transcript expression of genes (ACO, ehhadh, and fas) indicate that TP disrupt lipid metabolism in zebrafish larvae. The change in expression of genes (ndufs4, Sdhα, and uqcrc2) involved in the mitochondrial respiratory complexes, and genes (polg1 and tk2) involved in the mitochondrial DNA replication and transcription indicates that these adverse effects on carbohydrate and lipid metabolism are caused by mitochondrial dysfunction.

Interactions between Brassica Biofumigants and Soil Microbiota: Causes and Impacts

Biofumigation is used to control soil-borne plant diseases, and it has paramount importance to reduce the cost of chemical fumigants. Information about the field control efficacies and impacts of Brassica-based biofumigation (BBF) on soil bacterial and fungal microbiota is scattered in the literature. Therefore, this review summarizes and discusses the nature and the underlying causes of soil bacterial and fungal community dynamics in response to BBF. In addition, the major factors influencing the interaction between a biofumigant and soil microbiota are discussed. The pros and cons of BBF to soil microbiota and the subsequent impacts on sustainable farming practices are also highlighted.

Sublethal effects of propiconazole on the metabolism of lambari Deuterodon iguape (Eigenmann 1907), a native species from Brazil

The objective of this study was to analyze the sublethal effects of propiconazole on Deuterodon iguape, a native fish common in Brazil, which has potential for aquaculture and use as a bioindicator. The hypothesis was to test whether D. iguape has a metabolism similar to Danio rerio so that its use in bioassays may be validated. Lethal concentration (LC50) and metabolic rates were studied in fish exposed to propiconazole. Specific oxygen consumption and ammonia excretion for D. iguape and D. rerio increased by 0.01 µg L^-1 and then decreased as the propiconazole concentration increased. The decrease in the averages of specific oxygen consumption at the concentration of 0.1 µg L^-1 represented a reduction in the metabolic rate compared to the control of 71% for D. iguape and 40% D. rerio. For the ammonia excretion, at the same concentration, there was a reduction of 68.7% and 45.4% for D. iguape and D. rerio, respectively. When comparing ammonia excretion of the two species for each concentration of propiconazole, there was a significant difference (p < 0.05) in relation to the control and for the highest concentration (0.1 µg L^-1). As for specific oxygen consumption, there was a statistically significant difference only for the concentration of 0.1 µg L^-1. D. iguape proved to be a good and useful bioindicator for ichthyologists or ecologists in studies of moderate pesticide contamination in freshwater aquatic environments, as its metabolic response was similar to D. rerio.

Degradation pathway of triazole fungicides and synchronous removal of transformation products via photo-electrocatalytic oxidation tandem MoS2 adsorption

A simple and effective tandem process of photo-electrocatalytic oxidation (PECO)-MoS₂ adsorption was developed for the synchronous removal of triazole fungicides (TFs) and toxicological transformation products (TPs). In order to accurately identify trace TPs and evaluate degradation pathway during water treatment, a sensitive analytical method was developed on the basis of the stir bar sorptive extraction (SBSE) pretreatment tandem LC-MS/MS technique. Firstly, the typical TFs (PRO, TET, and DIN, C₀ = 1.0 mg/L) in actual water samples were treated under the optimal process (bias voltage 1.8 V, pH 4, irradiation intensity 50 mW/cm², 0.05 g MoS₂/100 mL, 350 rpm, adsorption of 5 min). The result indicated that the residues of PRO, TET, and DIN in secondary effluent were 0.0973, 0.0617, and 0.0012 mg/L, respectively, with the removal rates of 90.3%, 93.8%, and 99.9%, respectively, undergoing 30-min photo-electrocatalysis and 5-min adsorption. The alkaline medium was favorable for the adsorption of MoS₂ to TFs. The assessment results of potential cancer risk indicated that the residues of TFs in secondary effluent were safe for drinking water consumption. Besides, the major TPs were identified via the SBSE-HRLC-MS/MS technique, and one possible transformation pathway of TFs was proposed. TFs mainly underwent dehydrochlorination, cyclization, hydroxylation, etc. to produce a series of nitrogenous heterocyclic compounds that possess higher polarity than parents, hinting that TPs might pose potential aquatic toxicity. However, TPs can be removed synchronously by this tandem technique. The current study can provide a theoretical basis for the harmless treatment of TFs in the water environment.

Sodium dehydroacetate exposure decreases locomotor persistence and hypoxia tolerance in zebrafish

Environmental exposure to sodium dehydroacetate (DHA-S) is inevitable as DHA-S is a high-volume preservative widely used in cosmetics, processed foods and personal care products. DHA-S is absorbed rapidly when administered orally or on the skin and generally considered to be safe and well tolerated. However, DHA-S has recently been reported to induce weight loss and allergic contact dermatitis, yet little is known about how DHA-S affect the related biological processes. Here, we characterize the biological effects of DHA-S on zebrafish model by directly waterborne exposure. Zebrafish is susceptible to DHA-S exposure at early developmental stage. DHA-S decreased the hatch rate and locomotor persistence of zebrafish, and eventually induced lethality during the continuous exposure at relatively low concentrations of commonly addition. Acute DHA-S exposure decreased respiration capacity in larval zebrafish, promoted the expression of HIF-1α (hypoxia-inducible factor-1α) and caused rapid adult zebrafish death in 30 h. We further demonstrated that DHA-S inhibited the activity of succinate dehydrogenase (SDH) inducing respiratory chain interruption, energy deficiency and organic acids accumulation. These results suggest that the approved DHA-S may pose serious environmental/ecological pressures on the aquatic animal's migration.

DNA methylation and histone modifications are essential for regulation of stem cell formation and differentiation in zebrafish development

The complex processes necessary for embryogenesis require a gene regulatory network that is complex and systematic. Gene expression regulates development and organogenesis, but this process is altered and fine-tuned by epigenetic regulators that facilitate changes in the chromatin landscape. Epigenetic regulation of embryogenesis adjusts the chromatin structure by modifying both DNA through methylation and nucleosomes through posttranslational modifications of histone tails. The zebrafish is a well-characterized model organism that is a quintessential tool for studying developmental biology. With external fertilization, low cost and high fecundity, the zebrafish are an efficient tool for studying early developmental stages. Genetic manipulation can be performed in vivo resulting in quick identification of gene function. Large-scale genome analyses including RNA sequencing, chromatin immunoprecipitation and chromatin structure all are feasible in the zebrafish. In this review, we highlight the key events in zebrafish development where epigenetic regulation plays a critical role from the early stem cell stages through differentiation and organogenesis.

A comprehensive review on environmental toxicity of azole compounds to fish

BACKGROUND

Azoles are considered as one of the most efficient fungicides for the treatment of humans, animals, and plant fungal pathogens. They are of significant clinical importance as antifungal drugs and are widely used in personal care products, ultraviolet stabilizers, and in aircraft for its anti-corrosive properties. The prevalence of azole compounds in the natural environment and its accumulation in fish raises questions about its impact on aquatic organisms.

OBJECTIVES

The objective of this paper is to review the scientific studies on the effects of azole compounds in fish and to discuss future opportunities for the risk evaluation.

METHODS

A systematic literature search was conducted on Web of Science, PubMed, and ScienceDirect to locate peer-reviewed scientific articles on occurrence, environmental fate, and toxicological impact of azole fungicides on fish.

RESULTS

Studies included in this review provide ample evidence that azole compounds are not only commonly detected in the natural environment but also cause several detrimental effects on fish. Future studies with environmentally relevant concentrations of azole alone or in combination with other commonly occurring contaminants in a multigenerational study could provide a better understanding.

CONCLUSION

Based on current knowledge and studies reporting adverse biological effects of azole on fish, considerable attention is required for better management and effective ecological risk assessment of these emerging contaminants.

Mixtures of co-occurring chemicals in freshwater systems across the continental US

Trace chemicals are common in marine and freshwater ecosystems globally. It is recognized that in the environment, individual chemicals are rarely found in isolation. Insufficient work has examined which chemicals co-occur and which methods best identify these mixtures. Using an existing data set, we found evidence that simple correlation analysis is better at identifying mixtures of commonly co-occurring trace chemicals than more commonly used PCA methods. Moreover, simple correlation analysis, unlike PCA, can be used in cases with unbalanced designs and with data points below reportable limits. Application of this approach allowed identification of 10 groups of chemicals commonly found together in freshwaters of the continental US, representing common "chemical syndromes." Better identification of co-occurring chemical combinations could aid in our understanding of biological and ecological effects of aquatic contaminants. This research provides evidence of correlation analyses as a more effective method for identifying commonly co-occurring aquatic contaminants. We also examined the patterns of these mixtures with a dataset consisting of concentrations of 406 trace chemicals from 38 sample locations across the continental US.

Tralopyril induces developmental toxicity in zebrafish embryo (Danio rerio) by disrupting the thyroid system and metabolism

Tralopyril, an antifouling biocide, widely used in antifouling systems to prevent underwater equipment from biological contamination, which can pose a potential risk to aquatic organisms and human health. However, there is little information available on the toxicity of tralopyril to aquatic organisms. Herein, zebrafish (Danio rerio) were used to investigate the toxicity mechanisms of tralopyril and a series of developmental indicators, thyroid hormones, gene expression and metabolomics were measured. Results showed that tralopyril significantly decreased the heart-beat and body length of zebrafish embryos-larvae exposed to 4.20 μg/L or higher concentrations of tralopyril and also induced developmental defects including pericardial hemorrhage, spine deformation, pericardial edema, tail malformation and uninflated gas bladder. Tralopyril decreased the thyroid hormone concentrations in embryos and changed the transcriptions of the related genes (TRHR, TSHβ, TSHR, Nkx2.1, Dio1, TRα, TRβ, TTR and UGT1ab). Additionally, metabolomics analysis showed that tralopyril affected the metabolism of amino acids, energy and lipids, which was associated with regulation of thyroid system. Furthermore, this study demonstrated that alterations of endogenous metabolites induced the thyroid endocrine disruption in zebrafish following the tralopyril treatment. Therefore, the results showed that tralopyril can induce adverse developmental effects on zebrafish embryos by disrupting the thyroid system and metabolism.

Competitive Adsorption and Mobility of Propiconazole and Difenoconazole on Five Different Soils

Propiconazole (PPC) and difenoconazole (DFC) are often combined for field applications. The resulted co-exsistence of PPC and DFC may have an effect on the fate of their individuals in soil. In this study, adsorption, desorption and leaching of PPC and DFC alone and their combinations were investigated in five different soils. Adsorption of PPC and DFC was significantly different on each soil with the Freundlich adsorption coefficients of 2.86-28.69 and 14.86-98.93 negatively correlated with soil pH, respectively. In addition, adsorption of PPC and DFC was declined by 27.12-37.59% and 17.28-25.35% with the presence of coexisting DFC and PPC, respectively. Mobility of PPC and DFC in tested soils was enlarged in coexisting system. The results indicate that adsorption, desorption and mobility of PPC and DFC were mainly affected by soil pH, and these behaviors of individual PPC and DFC were obviously altered by their co-existence.

The effects of a short-term exposure to propiconazole in zebrafish (Danio rerio) embryos

Propiconazole (PCZ) is a widely used fungicide around the world and was frequently detected in surface waters, which would pose risk to aquatic organisms. Previous studies indicated that PCZ has high toxicity to different kinds of fish. However, most of the studies focus on the toxicity and mechanisms of PCZ to adult fish, the potential toxicity mechanism of PCZ to fish embryos is still poorly understood. The present study investigated the effects of PCZ on content of reactive oxygen species (ROS) and malondialdehyde (MDA); activities of superoxide dismutase (SOD), catalase (CAT), and Na⁺-K⁺-ATPase; and expression level of genes related to oxidative stress, cell apoptosis, and innate immune system in zebrafish embryos after 96-h exposure. The results showed that 5.0 mg/L PCZ induced oxidative damage in zebrafish embryos, as indicated by increased ROS and MDA content and alteration of antioxidative enzyme activity. The activity of Na⁺-K⁺-ATPase in zebrafish embryos was significantly inhibited after exposure to 0.5 mg/L PCZ. The expression levels of bax, p53, casp-3, casp-9, and apaf-1 were significantly increased, indicating that cell apoptosis was caused in embryos by 5.0 mg/L PCZ. The expression level of interleukin-1b (IL-1b) and IL-8 increased after exposure to 0.5 mg/L PCZ, but that of IL-1b, IL-8, and cxcl-c1c (chemokine (C-X-C motif) ligand 18b) decreased in 5.0-mg/L PCZ treatment group, indicating an immunotoxicity effect. Our results suggest that oxidative damage, cell apoptosis, and immunotoxicity would be induced in zebrafish embryos after short-term exposure to PCZ.

Is sodium carboxymethyl cellulose (CMC) really completely innocent? It may be triggering obesity

The toxicity of sodium carboxymethyl cellulose (CMC), which has GRAS status and has been determined as "ADI non specified", was re-evaluated with a new modelling and molecular-based data. For this purpose, CMC, a food additive, was injected to the yolk sac (food) of the zebrafish embryo by the microinjection method at the 4th hour of fertilization at different concentrations. As a result, it was found that CMC showed no toxic effects within the framework of the parameters studied. But, we determined increasing lipid accumulation in zebrafish embryos exposed to CMC in a dose-dependent manner. To elucidate the mechanism underlying this lipid accumulation, the expression levels of genes related to obesity-linked lipid metabolism were examined. Our findings show that while CMC does not cause a toxic effect in zebrafish embryos, it can lead important effects on lipid metabolism by causing changes in the expression of some genes associated with obesity.

Investigation into the sub-lethal effects of the triazole fungicide triticonazole in zebrafish (Danio rerio) embryos/larvae

Global use of azole fungicides is expected to increase over the next several years. Triticonazole is a triazole fungicide that is used for turf protection, residential, and other commercial applications. As such, it can enter local rural and urban water systems via run-off and rain events. Early life stages of aquatic organisms can be susceptible to pesticides that enter the water, but in the case of triticonazole, data on the potential for subacute toxicity are lacking. Here, we determined the effects of triticonazole on development, oxygen consumption rates, and locomotor activity in zebrafish to address this knowledge gap. Wild-type zebrafish (ABTu strain) embryos and larvae were exposed to triticonazole (1-100 μM) in early development for different lengths of time depending on the assay conducted. Triticonazole did not affect survival nor induce significant deformity (pericardial edema, skeletal defects) in zebrafish at doses up to 100 μM. Oxygen consumption rate was measured in embryos after 24 and 48 hour exposure to triticonazole beginning at ∼6 hpf using the XF_e flux analyzer. Triticonazole did not affect basal respiration, oligomycin-induced ATP linked respiration, FCCP-induced maximum respiration, proton leak, spare capacity, nor non-mitochondrial respiration at doses up to 100 μM for 24 hours, even for exposure up to 250 μM for 48 hours. To determine whether the fungicide affected larval swimming activity, the visual motor response test was conducted following triticonazole exposure for 6 days. Larval zebrafish exposed to triticonazole showed hypoactivity in the dark following a 100 μM treatment, suggesting that the fungicide can affect the locomotor activity of zebrafish, albeit at relatively high levels. Given the fact that sublethal biological responses were absent at lower environmentally relevant concentrations, we conclude that triticonazole, relative to other triazole fungicides and types of pesticides, exhibits a relatively low risk of toxicity to the early life stages of fish.

Life cycle exposure to propiconazole reduces fecundity by disrupting the steroidogenic pathway and altering DNA methylation in zebrafish (Danio rerio)

Propiconazole is fungicide widely used in agriculture, which may enter aquatic ecosystems and affect organisms. In this study, zebrafish (Danio rerio) were exposed to environmentally relevant levels of propiconazole throughout the life cycle, from embryo to sexually mature adults, and the effects on growth, reproduction, and offspring viability were investigated. To investigate the mechanisms of propiconazole action, the sex steroid hormones and the expression of genes related to the hypothalamus-pituitary-gonad-liver (HPGL) axis and DNA methylation were examined. Growth decreased in the parental zebrafish (F0) after exposure to propiconazole for 120 days. In males, increases in the levels of 17β-estradiol and vitellogenin were observed. The alterations in sex steroid hormones were regulated by the expression of genes involved with the HPGL axis. The decreases in fecundity and fertilization of the F0 was induced by the global DNA methylation, and then may result in the abnormal development of the F1. Therefore, propiconazole disrupted the steroidogenic pathway and caused changes in global DNA methylation that induced reproductive toxicity.

Toxicity effects in zebrafish embryos (Danio rerio) induced by prothioconazole

Triazole fungicides are widely used in agriculture production and have adverse impacts on aquatic organisms. As one of the triazole fungicides, prothioconazole has been reported to cause many toxicological effects, but its risks to aquatic organisms are unknown. In this study, we systematically explored the toxicity effects of prothioconazole exposure on zebrafish embryos (Danio rerio) involving in developmental toxicity, oxidative damage and metabolism disorders. The results showed that prothioconazole exposure to zebrafish embryos produced a series of toxic symptoms, including hatching inhibition, shortening of body length, pericardial cyst and yolk cyst. In addition, prothioconazole exposure caused significant lipid peroxidation and oxidative damage. Particularly, we also found that metabolites and genes involved in lipid metabolism also showed significant changes. This study may provide theoretical basis for systematically assessing the potential risks of zebrafish embryos with prothioconazole exposure.

Angularly Prenylated Indole Alkaloids with Antimicrobial and Insecticidal Activities from an Endophytic Fungus Fusarium sambucinum TE-6L

Bioactivity-guided isolation of the endophytic fungus Fusarium sambucinum TE-6L residing in Nicotiana tabacum L. led to the discovery of two new angularly prenylated indole alkaloids (PIAs) with pyrano[2,3-g]indole moieties, amoenamide C (1) and sclerotiamide B (2), and four known biosynthetic congeners (3-6). Their structures were determined by comprehensive spectroscopic techniques, electronic circular dichroism (ECD), and X-ray diffraction. Compound 1 containing the bicyclo[2.2.2]diazaoctane core and indoxyl unit is rarely reported. All the compounds were evaluated for their antimicrobial and insecticidal activities. Notably, compounds 1-3 showed potent inhibitory effects against three human- and one plant-pathogenic bacterium, and seven plant-pathogenic fungi. Compounds 2-4 also exhibited remarkable larvicidal activity against first instar larvae of the cotton bollworm Helicoverpa armigera with mortality rates of 70.2%, 83.2%, and 70.5%, respectively. Further toxicity tests on zebrafish embryos were performed to evaluate the potential toxicity of PIAs. Of significance was that compound 3 in particular exhibited the highest activities but the lowest effects on the hatching of embryos among all the compounds. This study provides a basis for understanding developmental toxicity of PIAs exposure to zebrafish embryos, and also indicates the potential environmental risks of other natural compounds exposure in the aquatic ecosystem.