Kinetics and sorption behavior of glyphosate and tricyclazole for their efficient retention in biomixtures.

The present investigation aims to study adsorption-desorption behavior of glyphosate and tricyclazole in rice straw-compost biomixtures. To enhance pesticide adsorption and performance of the bio-purification system, rice straw-compost (BM) biomixture was mixed with wheat straw biochar (WBC, 1% and 5%), and adsorption of both pesticides in control (BM) and WBCBM(1%) and WBCBM(5%) biomixtures was compared. The kinetics study suggested that the pseudo-second-order model best explained the time-dependent adsorption of both pesticides and intraparticle adsorption was not the rate-determining step. Tricyclazole was more sorbed than glyphosate in all biomixtures which can be attributed to its lower water solubility. The WBC increased the sorption of both pesticides, but the effect varied with the nature of pesticides and biochar content. The adsorption coefficient values in BM, WBCBM(1%), and WBCBM(5%) biomixtures were 26.74, 38.16, and 51.97 (glyphosate) and 38.07, 59.94, and 84.54 (tricyclazole), respectively. The adsorption data was subjected to the Freundlich, the Langmuir, and the Temkin isotherms, and among them, the Freundlich isotherm best explained pesticide adsorption behavior. Desorption results suggested that the adsorption of glyphosate was more irreversible than tricyclazole and depended upon initial pesticide concentration. This study suggested that biochar mixed rice straw-compost biomixtures can be exploited in bio-purification systems for glyphosate and tricyclazole.

1,8-dihydroxy naphthalene (DHN) - melanin confers tolerance to cadmium in isolates of melanised dark septate endophytes.

The contribution of 1,8-dihydroxy naphthalene (DHN) melanin to cadmium (Cd) tolerance in two dark septate endophytes (DSE) of the genus Cadophora with different melanin content was investigated in vitro. The DSE isolate Cad#148 with higher melanin content showed higher tolerance to Cd than the less melanised Cad#149. Melanin synthesis was significantly reduced by Cd in both isolates with uninhibited melanin synthesis, in a dose-dependent manner. Inhibition of melanin synthesis by tricyclazole reduced the relative growth of Cad#148 exposed to Cd and did not affect Cad#149. Cd accumulation was not altered by tricyclazole in the two isolates, but it increased catalase and reduced glutathione reductase activity in more melanised Cad#148, indicating higher stress levels. In contrast, in Cad#149 the enzyme activity was less affected by tricyclazole, indicating a more pronounced role of melanin-independent Cd tolerance mechanisms. Cd ligand environment in fungal mycelia was analysed by extended EXAFS (X-ray absorption fine structure). It revealed that Cd was mainly bound to O- and S-ligands, including hydroxyl, carboxyl, phosphate and thiol groups. A similar proportion of S- and O- ligands (~35% and ~65%) were found in both isolates with uninhibited melanin synthesis. Among O-ligands two types with Cd-O-C- and Cd-O-P- coordination were identified. Tricyclazole altered Cd-O- ligand environment in both fungal isolates by reducing the proportion of Cd-O-C- and increasing the proportion of Cd-O-P coordination. DHN-melanin, among other tolerance mechanisms, significantly contributes to Cd tolerance in more melanised DSE fungi by immobilising Cd to hydroxyl groups and maintaining the integrity of the fungal cell wall.

Melanin and chromoblastomycosis agents: Characterization, functions, and relation with antifungals.

Melanins are a diverse group of dark pigments with similar properties. In fungi, the most studied is the dihydroxynaphtalene (DHN)-melanin, present in several species including all the chromoblastomycosis agents, a chronic, disabling, and recalcitrant subcutaneous mycosis. It is synthesized in a pathway known as the pentaketide pathway, which has the agrochemical tricyclazole as an inhibitor, widely used in in vitro studies because it does not prevent the growth of fungi. There are different methodologies for qualitative and quantitative analyses of DHN-melanin, which made it possible to discover its important structural and antioxidant functions, with melanin acting as a protective factor against the host's immune system. Also, it can interact with some of the main antifungals of medical interest, reducing its activity and the susceptibility of fungi to these agents. This review aims to discuss the aspects of DHN-melanin, focusing on chromoblastomycosis, bringing the main findings of the published scientific studies, and highlighting the need for further research to understand this important fungal pathogenicity and a virulence factor.

Predicting rice pesticide fate and transport following foliage application by an updated PCPF-1 model.

The Pesticide Concentration in Paddy Field (PCPF-1) model has been successfully used to predict the fate and transport of granular pesticides applied to the paddy fields. However, it is not applicable for pesticides in foliar formulation while previous studies have reported that foliar application may increase the risks of rice pesticide contamination to the aquatic environment due to pesticide wash-off from rice foliage. In this study, we developed and added a foliar application module into the PCPF-1 model to improve its versatility regarding pesticide application methods. In addition, some processes of the original model such as photodegradation were simplified. The updated model was then validated with data from previous studies. Critical parameters of the model were calibrated using the Sequential Uncertainty Fitting version 2 (SUFI-2) algorithm. The calibrated model simulated pesticide dissipation trend and concentrations with moderate accuracy in the two paddy compartments including rice foliage and paddy water. The accuracy of the predicted soil concentrations could not be evaluated since no observed data were available. Although the p-factor and r-factor obtained using the SUFI2 algorithm indicated that the uncertainty encompassed in the predicted concentrations was rather high, the daily predicted pesticide concentrations in rice foliage and paddy water were satisfactory based on the NSE values (0.36-0.89). The updated PCPF-1 model is a flexible tool for the environmental risk assessment of pesticide losses and the evaluation of agricultural management practices for mitigating pesticide pollution associated with rice production.

The rhizomicrobiomes of wild and cultivated crops react differently to fungicides.

The fungicides used to control diseases in cereal production can have adverse effects on non-target microbial communities, with possible consequences for plant health and productivity. Although we know that fungicides affect microbial community structure and soil activities, it is unclear how crop cultivars have altered the impact of fungicides on rhizomicrobiomes. In this study, the rhizosphere bacterial and fungal communities and structures of cultivated crops and their wild relatives were studied by Illumina MiSeq sequencing analysis. The results indicated that the rhizomicrobiome communities of wild crops reacted more strongly to fungicides than that of their cultivated relatives. Furthermore, fungal community composition was more affected by fungicides than bacterial community composition. Remarkably, the same trend was observed in both soybean and rice with regard to the influence of crop cultivar on the response of the rhizomicrobiome to fungicide application, although the level of the response was not similar. We report for the first time that the rhizomicrobiomes of wild crops reacted more strongly to fungicides than the rhizomicrobiomes of cultivated crops.

The ADME profile of the fungicide tricyclazole in rodent via the oral route: A critical review for human health safety assessment.

Herein, we publish data from regulatory studies investigating the oral ADME (absorption, distribution, metabolism, excretion) of tricyclazole in vivo, in silico and in vitro. The oral route is relevant to human dietary exposure assessment. Tricyclazole is readily absorbed and highly bioavailable in rodents (>86%) with indication of saturation of absorption at high doses. Enterohepatic recirculation is evident. Excretion occurs quickly both via urinary (31-64%) and faecal routes (39-65%), with substantial biliary elimination in the rat (≥58%). The tricyclazole-derived radioactivity is distributed to major organs, including those investigated in in vivo genotoxicity studies (liver, kidney, gastrointestinal tract and bone marrow). There is no evidence of bioaccumulation. Metabolism is extensive (approximately 30 metabolites), with the liver being identified as the primary metabolism organ with Phase I and II enzymes involved. Several metabolites are formed following an initial cleavage of the central thiazole ring, with no loss of free triazole from the remaining phenyl ring. A group of 4 metabolites derive from an initial oxidation step with the formation of the tricyclazole-alcohol, a relevant crop metabolite, and account for up to 13% of the administered dose. In vitro metabolism, investigated with liver microsomes, confirmed that humans do not form unique metabolites.

Effect of tricyclazole on morphology, virulence and gene expression of Aspergillus aculeatus for management of soft rot disease in peach.

AIMS: Aspergillus aculeatus, a pathogen of peaches, can cause soft rot and lead to economic losses in agricultural production. However, studies on the prevention of soft rot caused by A. aculeatus have rarely been reported. Tricyclazole (TCZ) is a fungicide that has been widely used in disease prevention of various crops but the inhibitory mechanism of TCZ on A. aculeatus is unknown. Our aim was to determine the effects of TCZ on A. aculeatus. METHODS AND RESULTS: In our study, TCZ inhibited the growth of fungal colonies when applied at 0·5-6 mmol l-1 and inhibited the production of melanin at 3 mmol l-1 . Conidia exposed to TCZ were less effective at causing the disease in inoculated samples, and electrical conductivity, divulgation of nucleic acids and proteins rose with increasing concentrations of TCZ. Microscopic results suggest that TCZ damages not only the cell wall but also the cell membrane. Results of qRT-PCR showed that TCZ had no significant effect on the regulation of genes coding for laccase, apoptosis and hypothetical protein; however, it significantly down-regulated genes coding for cellulase, chitinase and sterol. CONCLUSIONS: Tricyclazole can influence the pathogenic ability of A. aculeatus by damaging the cell structure of hyphae and conidia, reducing the melanin production, and altering the expression of pathogenic-related gene. SIGNIFICANCE AND IMPACT OF THE STUDY: The results explained the potential cause and mechanism TCZ produced in A. aculeatus. Our research offers scientific insights into future research interest relative to using TCZ in the treatment of soft rot caused by A. aculeatus.

Toxicological analysis of Eisenia fetida in soil under the coexistence of rockwool substrate andtricyclazole.

This study investigated the combined effects of rockwool, a novel seedling substrate, and tricyclazole (TCA) on the bioavailability of TCA to Eisenia fetida. The single addition of rockwool and TCA alone to the soil inhibited the growth of E. fetida. A high concentration (300 mg·L-1) of TCA significantly decreased the biomass of E. fetida. The addition of 20-mesh rockwool reduced this effect on earthworm biomass by decreasing the soil TCA through adsorption, effectively mitigating TCA bioaccumulation in earthworms. A mechanistic analysis showed that the Mg-O functional group on the rockwool surface combined with the CC functional group in TCA to generate Mg-O-C, and the adsorption process was dominated by chemisorption. Toxicology experiments demonstrated that malondialdehyde and cellulase could be used as biomarkers of inhibitory effects of combined rockwool and TCA in soil on E. fetida. Macrogenomic analyses revealed that small particle sizes and high concentrations of rockwool caused co-stress effects on earthworms when TCA was present. When the particle size of rockwool increased, the toxic effect of TCA on earthworms instead decreased at higher rockwool concentrations. Therefore, in practical agricultural production, the particle size of rockwool can be controlled to realize the adsorption of TCA and reduce the toxic effects of TCA and rockwool on earthworms.

A paper-based lateral flow immunochromatographic sensor for the detection of tricyclazole in rice.

Tricyclazole is commonly used to prevent rice blast to meet the carbohydrate intake needs of half of the global population, and a large number of toxicological reports indicate that monitoring of tricyclazole is necessary. Here, we analyzed the structure of tricyclazole and designed different hapten derivatization strategies to prepare a high-performance monoclonal antibody (half inhibition concentration of 1.61 ng/mL), and then a lateral flow immunochromatographic sensor based on gold nanoparticles for the detection of tricyclazole in rice, with a limit of detection of 6.74 µg/kg and 13.58 µg/kg in polished and brown rice, respectively. The recoveries in rice were in the range of 84.6-107.4%, no complex pretreatment was required for comparison with LC-MS/MS, and the comparative analysis demonstrated that our method had good accuracy and precision. Therefore, the developed lateral flow immunochromatographic analysis was a reliable and rapid means for the on-site analysis of tricyclazole in rice.

Setting of import tolerance for tricyclazole in rice.

In accordance with Article 6 of Regulation (EC) No 396/2005, the applicant Corteva Agriscience submitted a request to the competent national authority in Italy to set an import tolerance for the active substance tricyclazole in rice. The data submitted in support of the request were found to be sufficient to derive an maximum residue level (MRL) proposal for rice. Adequate analytical methods for enforcement are available to control the residues of tricyclazole in rice at the validated limit of quantification (LOQ) of 0.01 mg/kg. Based on the risk assessment results, EFSA concluded that the short-term and long-term intake of residues resulting from the use of tricyclazole according to the reported agricultural practice is unlikely to present a risk to consumer health.

Dark Pigments in Entomopathogenic Fungal Microsclerotia: Preliminary Evidence of a 1,8-Dihydroxynaphthalene-melanin-like Compound in Metarhizium robertsii.

Metarhizium robertsii microsclerotia are fungal aggregates composed of compacted, pigmented hyphae. As they are highly tolerant to desiccation and produce infective conidia, they are promising candidates to be formulated as bioinsecticides. Despite this potential, the nature of the pigments within these structures remains unclear. In this study, routine culture media used for the differentiation of M. robertsii microsclerotia were supplemented with four melanin inhibitors, and the resulting propagules were characterized. Inhibitors of the 1,8-dihydroxynaphthalene (DHN)-melanin biosynthetic pathway such as tricyclazole and guaiacol induced significant phenotypic and molecular modifications in the obtained M. robertsii propagules, which exhibited a more spherical shape, reduced size, and increased susceptibility to desiccation, heat, and oxidative stress than microsclerotia obtained without inhibitors. Additionally, genes encoding for a polyketide synthase (Mrpks2) and a putative 1,3,6,8-tetrahydroxynaphthalene reductase (Mrthnr), potentially involved in the DHN-melanin biosynthetic pathway, were upregulated in fungi grown in the inhibitor-added media. In conclusion, M. robertsii microsclerotia contain melanins of type DHN that might play a role in both microsclerotia differentiation and environmental stress tolerance.

Detection of pesticide residues on flexible and transparent fluorinated polyimide film based on surface-enhanced Raman spectroscopy technology.

BACKGROUND: Excessive pesticide residues will seriously endanger human health. The complexity and lag of the current popular analytical methods hinder the timeliness of food safety analysis. Surface-enhanced Raman scattering (SERS) was an ultra-sensitive vibration spectroscopy technology with the advantages of less time cost, non-destructive and semi-quantitative detection, which has attracted much attention in the rapid field detection of pesticide residue. It was clear that we need an efficient and convenient substrate for pesticide residue detection based on SRES technology, which needs to be portable, flexible, transparent and easy to detect irregular object surfaces. RESULTS: A novel SERS sensor was designed to detect single and multi-component pesticide residues on irregular fruit and vegetable surfaces by in-situ growth of silver nanoparticles on a flexible and transparent fluorinated polyimide (FPI) substrate. Among them, Ag NPs were synthesized by liquid phase reduction method (AgNO3-PVP and NaBH4). The results showed that the detection limit of 1-4 BDT was down to 10-10 mol L-1, the enhancement factor (EF) was up to 1.57 × 107, and relative standard deviation (RSD) was 7.49 %. By this method, tricyclazole solution at a concentration of 0.01 mg L-1 was still detectable by the FPI@Ag SERS substrate. The linear quantification was achieved in the range from 100 mg L-1 to 0.01 mg L-1. Two mixed pesticides, tricyclazole and imazalil, were also successfully distinguished. SIGNIFICANCE: This represents the formation of a flexible, foldable and transparent substrate for rapid on-site detection. Results can be obtained in <5 min by attaching the substrate to the substance to be tested. And the SERS substrate prepared with high sensitivity, stability, portable and convenient analysis, which provided new ideas for efficient and rapid household food safety detection.

Functionalized silver nanoparticles as colorimetric probes for sensing tricyclazole.

A colorimetric assay for highly selective and sensitive detection of tricyclazole using fluorescein-functionalized silver nanoparticles (F-AgNPs) as sensing probes was investigated. As the addition of tricyclazole to F-AgNPs, a drastic decrease in the absorbance at 394 nm was detected, which was accompanied with a noticeable color change from yellow to gray. The sensing mechanism involved an interaction between tricyclazole and F-AgNPs, which led to aggregation of the latter, inducing a color change from yellow to gray. An excellent linear calibration curve (R2 = 0.9994) was achieved between absorbance at 394 nm and the tricyclazole concentration in the range between 0.06 and 1.0 ppm. Moreover, the detection limit was estimated at 0.051 ppm. The developed colorimetric assay also showed good selectivity and was successfully utilized to quantify tricyclazole in rice samples with satisfactory recoveries. The proposed assay has been successfully applied for monitoring tricyclazole in rice samples.

Separation and concentration of o-toluidine and tricyclazole from water with micellar enhanced ultrafiltration based on sodium dodecyl sulfate surfactant.

Micellar enhanced ultrafiltration (MEUF) of o-toluidine and tricyclazole in aqueous stream using polyethersulfone (PES) hollow-fibre membrane of 6 kDa molecule weight cut-off (MWCO) and sodium dodecyl sulfate (SDS) as anionic surfactant was studied. It was found that the concentration ratio and adsorption ratio were better for the determination of the optimal pollutant or surfactant concentration than the rejection rate. The excessive dosage of surfactant had only limited effect on the separation and concentration of o-toluidine and tricyclazole but could further decrease the permeate flux. The transmembrane pressure had a significantly positive effect on the permeate flux and recovery ratio. o-Toluidine was significantly separated and concentrated by lowering the solution pH, while tricyclazole reached the best treatment efficiency in near-neutral pH condition. The sodium salts (i.e. Na2SO4, NaCl and Na2CO3) could lead to the increase in the adsorption ratio of SDS. However, Na2CO3 could result in the decrease in both the rejection rates and adsorption ratios of o-toluidine and tricyclazole. The distribution coefficient, micellar loading and micelle binding constant were evaluated to confirm the effectiveness for the MEUF treatment of these two pollutants.

Solubilization and separation of o-toluidine and tricyclazole in sodium dodecyl sulfate micelles in micellar enhanced ultrafiltration.

The solubilization laws of pollutants in micelles and their separation efficiency are very important in the successfully efficient application of micellar enhanced ultrafiltration (MEUF). The solubilization behavior of o-toluidine (OT) and tricyclazole (TC) into sodium dodecyl sulfate (SDS) micelles in MEUF was studied using nonlinear equation sets for concentration analysis, which resolved the issue on the overlap of absorption spectra of multicomponent compounds restricting the application of conventional ultraviolet (UV) spectroscopic method. The solubilization isotherms for both pollutants could be best explained by the Langmuir-Freudlich model (R2>0.99) followed by the modes of Langmuir and Freudlich, inferring the complexity of solubilization mechanism and solubilization advantage of monolayer over multilayer. The calculated thermodynamic parameters (ΔG0, ΔH0 and ΔS0) indicated that this process was endothermic and spontaneous. The solubilization of OT and TC well followed the pseudo second-order and pseudo first-order kinetics, respectively. The separation and recovery of SDS solubilizing these two pollutants were also investigated through lowering solution temperature to 2 °C followed by centrifugation. The best recovery rate of about 66% for SDS was achieved containing 10 and 5% of each initial amount of OT and TC, respectively, at near-neutral solution pH value. The recovery of SDS could decrease to some extent under alkaline and acidic conditions.

A critical Assessment of the Genotoxicity Profile of the Fungicide Tricyclazole.

Tricyclazole (8-methyl-[1,2,4]triazolo[3,4-b][1,3]benzothiazole) is a fungicide used globally on rice for treatment of the seasonal rice blast disease. Human exposure to this fungicide can occur via dietary and nondietary routes. In a battery of in vitro assays, tricyclazole did not induce gene mutations in bacteria (Ames test) or at the Hprt locus of CHO cells. It was also negative for the induction of micronuclei in human lymphocyte cultures and unscheduled DNA synthesis (UDS) in primary rat hepatocyte. Paradoxically, tricyclazole induced a mutagenic response at the Tk locus of the mouse lymphoma L5178Ycells (MLA), which occurred equally among small/large colony phenotypes. Selection of preexisting mutants leading to a false-positive response in the MLA was ruled out in follow-up experiments. In vivo, tricyclazole was negative in the rat liver UDS assay, mouse bone micronucleus test and a transgenic (MutaMouse) gene mutation assay in glandular stomach, liver, and kidney. Other supporting evidence for the lack of genotoxicity for tricyclazole comes from an in vivo study for sister chromatid exchanges in Chinese hamsters, and a dominant lethal test in the male germ cells of mice. The combined evidence from the genotoxicity studies together with the evidence from toxicokinetic, carcinogenicity, developmental, and reproductive toxicity studies confirm that mutagenicity does not occur in relevant in vivo systems. Data were also compared to potential animal and human exposure, mechanistic data on biological targets and data on analogues, confirming adequacy of the available data for hazard identification and risk assessment. Environ. Mol. Mutagen. 61:300-315, 2020. © 2019 Wiley Periodicals, Inc.

Unravelling the Role of Melanin in Cd and Zn Tolerance and Accumulation of Three Dark Septate Endophytic Species.

Dark septate endophytes (DSEs) are often trace element (TE)-tolerant fungi and are abundant in TE-polluted environments. The production of melanin, a black polymer found in cell walls, was hypothesized by several authors to play a role in the TE tolerance of DSEs. To test this hypothesis, we established a series of experiments using albino strains and melanin inhibitors and examined the responses to Cd and Zn. Six DSEs belonging to genera Cadophora sp., Leptodontidium sp. and Phialophora mustea, were evaluated. The strains mainly produced 1,8-dihydroxynaphthalene (DHN) melanin whereas 3,4-dihydroxyphenylalanin melanin was also synthetized. Cd and Zn decreased melanin synthesis in most of the strains. A reduction in melanin concentration in hyphae through the use of tricyclazole, an inhibitor of DHN-melanin synthesis, did not reduce the tolerance of the strains to Cd and Zn. Similarly, albino mutants of Leptodontidium sp. were not more sensitive to Cd and Zn than the WT strain. Moreover, tricyclazole-treated colonies accumulated less Cd but more Zn compared to untreated colonies. The Cd and Zn contents of Leptodontidium albino strains were variable and similar to that of the WT. The results suggest that melanin production is not an important functional trait that contributes to Cd and Zn tolerance, but might contribute to Cd accumulation.

Salt Stress Tolerance of Dark Septate Endophytes Is Independent of Melanin Accumulation.

Dark septate endophytes (DSEs) represent a diverse group of root-endophytic fungi that have been isolated from plant roots in many different natural and anthropogenic ecosystems. Melanin is widespread in eukaryotic organisms and possesses various functions such as protecting human skin from UV radiation, affecting the virulence of pathogens, and playing a role in development and physiology of insects. Melanin is a distinctive feature of the cell walls of DSEs and has been thought to protect these fungi from abiotic stress. Melanin in DSEs is assumed to be synthesized via the 1,8-dihydroxynaphthalene (DHN) pathway. Its function in alleviation of salt stress is not yet known. The aims of this study were: (i) investigating the growth responses of three DSEs (Periconia macrospinosa, Cadophora sp., and Leptodontidium sp.) to salt stress, (ii) analyzing melanin production under salt stress and, (iii) testing the role of melanin in salt stress tolerance of DSEs. The study shows that the three DSE species can tolerate high salt concentrations. Melanin content increased in the hyphae of all DSEs at 100 mM salt, but decreased at 500 mM. This was not reflected in the RNA accumulation of the gene encoding scytalone dehydratase which is involved in melanin biosynthesis. The application of tricyclazole, a DHN-melanin biosynthesis inhibitor, did not affect either salt stress tolerance or the accumulation of sodium in the hyphae. In addition, melanin biosynthesis mutants of Leptodontidium sp. did not show decreased growth performance compared to the wild-type, especially not at high salt concentrations. This indicates that DSEs can live under salt stress and withstand these conditions regardless of melanin accumulation.

Surface-enhanced Raman Spectroscopy Coupled with Dispersive Solid-phase Extraction for the Rapid Detection of Tricyclazole Residues in Rice and Brassica campestris L. ssp. chinensis var. utilis Tsen.

An efficient methodology has been developed to determine the tricyclazole residue in matrix based on surface-enhanced Raman scattering (SERS) coupled with dispersible matrix solid-phase extraction. After pretreatment and test conditions optimization, peaks at 1373 and 1317 cm-1 in the SERS spectrum were respectively selected as quantitative peaks for rice and Brassica campestris L. ssp. chinensis var. utilis Tsen, respectively. The matrix standard curve-external standard method was used to quantitatively conduct a statistical analysis. The correlation between the quantitative peak response and tricyclazole concentration showed a significant linear relationship with a correlation coefficient of R2 > 0.99. The lowest spiked concentration was determined to be the quantitative limit that was below the maximum residue limits of tricyclazole. This study provides a sensitive, stable and rapid approach for the analysis of tricyclazole in above matrix via SERS, and it will be a useful complement to the quantitative analysis of tricyclazole in a complex matrix.

Hepatotoxicity of tricyclazole in zebrafish (Danio rerio).

Tricyclazole is widely used in agriculture as a pesticide, but its toxicity in vertebrates is currently poorly evaluated. In this study, we used zebrafish to assess the toxicity of tricyclazole. We found that tricyclazole induces liver damage, or hepatotoxicity, in zebrafish, during both development and adulthood. In embryos, we found that tricyclazole affected the liver development rather than other endodermal tissues such as gut and pancreas. In both embryos and adult zebrafish livers, tricyclazole disrupted the relationship between oxidant and antioxidant system and resulted in reactive oxygen species (ROS) overload. Meanwhile, it triggered hepatocyte apoptosis and disturbed carbohydrate/lipid metabolism and energy demand systems. These results suggested that tricyclazole could cause severe consequences for vertebrate hepatic development and function.