Mechanistic insights into the parental co-exposure of T-2 toxin and epoxiconazole on the F1 generation of zebrafish (Danio rerio).

Mycotoxins and pesticides frequently coexist in agricultural commodities on a global scale. The potential transgenerational consequences induced by these substances pose a significant threat to human health. However, there is a lack of data concerning the effects of co-contamination by these chemicals in the F1 generation following parental exposure. This investigation delved into the mixture effects of T-2 toxin (T-2) and epoxiconazole (EPO) on the offspring of zebrafish (Danio rerio). The findings revealed that exposure across generations to a combination of T-2 and EPO resulted in toxicity in the larvae of the F1 generation. This was demonstrated by a significant increase in the levels or activities of malondialdehyde (MDA), thyroxine (T4), Caspase3, and cas9, along with a decrease in the levels of cyp19a, ERα, and ERß. These outcomes suggested that cross-generational exposure to T-2 and EPO in D. rerio disrupted oxidative balance, induced cell apoptosis, and affected the endocrine system. Moreover, these effects were magnified when the F1 generation was continuously exposed to these compounds. Notably, these adverse effects could persist in subsequent generations without additional exposure. This study underscored the potential dangers associated with the simultaneous presence of T-2 and EPO on the development of fish offspring and the resulting environmental hazards to aquatic ecosystems. These findings emphasized the significant health risks posed by cross-generational exposure and highlighted the need for additional legislative measures to address these concerns.

Glycometabolic disorder induced by chronic exposure to low-concentration imidacloprid in zebrafish.

The health risks induced by chronic exposure to low concentrations of imidacloprid (IMI) to zebrafish were investigated in this study. The results indicated that the growth of zebrafish was inhibited after being exposed to 10, 100, and 500 µg/L of IMI for 90 days. Moreover, the blood glucose levels in the IMI-exposed groups were significantly higher compared to the control group. Investigation into the development of zebrafish larvae revealed that IMI exposure hindered the development of the liver and pancreatic islets, organs crucial for glucose metabolism. In addition, the IMI-exposed groups exhibited reduced liver glycogen and plasma insulin levels, along with changes in the activity of enzymes and the transcription levels of genes associated with liver glucose metabolism. These findings suggest that IMI induces glycometabolic disorders in zebrafish. The analysis of intestinal flora revealed that several key bacteria associated with an elevated risk of diabetes were significantly altered in IMI-exposed fish. Specifically, a remarkable decrease was found in the abundance of the genera Aeromonas and Shewanella, which have been found closely related to the development of pancreatic islets. This implies that the alteration of key bacteria in the fish gut by IMI, which in turn affects the development of organs such as the pancreatic islets, may be the initial trigger for abnormalities in glucose metabolism. Our results revealed that chronic exposure to low concentrations of IMI led to glycometabolic disorder in fish. Therefore, considering the pervasive existence of IMI residues in the environment, the health hazards posed by low-concentration IMI to fish cannot be overlooked.

Rice false smut pathogen: implications for mycotoxin contamination, current status, and future perspectives.

Rice serves as a staple food across various continents worldwide. The rice plant faces significant threats from a range of fungal, bacterial, and viral pathogens. Among these, rice false smut disease (RFS) caused by Villosiclava virens is one of the devastating diseases in rice fields. This disease is widespread in major rice-growing regions such as China, Pakistan, Bangladesh, India, and others, leading to significant losses in rice plantations. Various toxins are produced during the infection of this disease in rice plants, impacting the fertilization process as well. This review paper lightens the disease cycle, plant immunity, and infection process during RFS. Mycotoxin production in RFS affects rice plants in multiple ways, although the exact phenomena are still unknown.

Co-exposure ochratoxin A and triadimefon influenced the hepatic glucolipid metabolism and intestinal micro-environment in mice.

Ochratoxin A (OTA) is a mycotoxin, and triadimefon (TDF) is a triazole fungicide. These compounds are prevalent in the environment, and their residues have been detected in crops. However, the precise health risks associated with mycotoxins and fungicides are not fully elucidated. In this work, five-week-old mice were gavage with OTA (0.3 and 1.5 mg/kg/day), TDF (10 and 50 mg/kg/day), and OTA + TDF (0.3 + 10 and 1.5 + 50 mg/kg/day) for 28 days. Exposure to OTA, TDF, and OTA + TDF led to significant alterations in liver total cholesterol (TC), triglyceride (TG), and glucose (GLU) levels, as well as in genes associated with glycolipid metabolism in mice. Reduced acylcarnitine levels in serum indicated that OTA, TDF, and co-exposure inhibited fatty acid (FA) ß-oxidation. Furthermore, OTA and TDF disrupted the integrality of the gut barrier function and altered the structure of the intestinal microbiota. These findings suggested that OTA, TDF, and their co-exposure might disrupt the intestinal barrier, alter the structure of the microbiota, and subsequently inhibit FA ß-oxidation, indicating the interference of OTA and TDF with glycolipid-related intestinal barrier dysfunction. Moreover, our data revealed a toxic additive effect between OTA and TDF, providing a foundation for assessing the combined toxicity risk of mycotoxins and fungicides.

Combined toxicity of aflatoxin B1 and tebuconazole to the embryo development of zebrafish (Danio rerio).

Mycotoxins and pesticides are pervasive elements within the natural ecosystem. Furthermore, many environmental samples frequently exhibit simultaneous contamination by multiple mycotoxins and pesticides. Nevertheless, a significant portion of previous investigations has solely reported the occurrence and toxicological effects of individual chemicals. Global regulations have yet to consider the collective impacts of mycotoxins and pesticides. In our present study, we undertook a comprehensive analysis of multi-level endpoints to elucidate the combined toxicity of aflatoxin B1 (AFB1) and tebuconazole (TCZ) on zebrafish (Danio rerio). Our findings indicated that AFB1 (with a 10-day LC50 value of 0.018 mg L-1) exhibits higher toxicity compared to TCZ (with a 10-day LC50 value of 2.1 mg L-1) toward D. rerio. The co-exposure of AFB1 and TCZ elicited synergistic acute responses in zebrafish. The levels of GST, CYP450, SOD, and Casp-9 exhibited significant variations upon exposure to AFB1, TCZ, and their combined mixture, in contrast to the control group. Additionally, eight genes, namely cat, cxcl-cic, il-1ß, bax, apaf-1, trß, ugtlab, and vtg1, displayed marked alterations when exposed to the chemical mixture as opposed to individual substances. Therefore, further exploration of the underlying mechanisms governing joint toxicity is imperative to establish a scientific basis for evaluating the risk associated with the combined effects of AFB1 and TCZ. Moreover, it is essential to thoroughly elucidate the organ system toxicity triggered by the co-occurrence of mycotoxins and pesticides.

Dissipation behavior and dietary risk assessment of cyclaniliprole and its metabolite in cabbage under field conditions.

Cyclaniliprole, a novel diamide insecticide, can successfully control Spodoptera litura (Fabricius, 1775) in cabbage. Understanding the residual level of cyclaniliprole in crops and the risk related to its dietary intake is imperative for safe application. Here, we established a simplified, sensitive method for simultaneous analysis of cyclaniliprole and its metabolite NK-1375 (3-bromo-2-((2-bromo-4H-pyrazolo[1,5-d]pyrido[3,2-b]-[1,4]oxazin-4-ylidene)amino)-5-chloro-N-(1-cyclopropylethyl)benzamide) in cabbage by liquid chromatography-tandem mass spectrometry (LC-MS/MS) to investigate their dissipation behavior and residual characteristics. Cyclaniliprole showed rapid dissipation in cabbage and had a half-life of 1.8-2.7 days. The highest residue of total cyclaniliprole (sum of cyclaniliprole and NK-1375) in cabbage from different pre-harvest intervals (3 and 5 days) was 0.25 mg/kg. Our results confirmed the generally low dietary risk quotient of cyclaniliprole (0.243-1.036%) among different age and gender groups in China. Therefore, cyclaniliprole did not pose an unacceptable risk to consumers. This study contributes to setting cyclaniliprole maximum residue limit in cabbage by assessing its dissipation fate and food safety risks.

Absorption and Distribution of Imidacloprid and Its Metabolites in Goldfish (Carassius auratus Linnaeus).

Imidacloprid (IMI) is the first-generation neonicotinoid insecticide. But, the long-term use of IMI as a pesticide has caused severe water pollution. Recently, the toxicity of IMI to aquatic organisms has received increasing attention. This study aimed to investigate the absorption and distribution of IMI in various tissues (gills, intestine, liver, muscle, brain and gonads) of goldfish through short-term and continuous exposure tests over 28 days. The results of short-term exposure indicated that the concentration of IMI and its metabolites in tissues at the transfer stage decreased steadily after 1 day of 40 mg/L IMI water treatment and was below the detection limit after 3 days. Continuous exposure for 28 days at various treatment concentrations showed that the concentrations of IMI and its metabolites differed significantly among the different tissues of the goldfish. In the 20 mg/L treatment group (S1), the highest concentration of IMI was found in the liver (12.04 µg/gtissue), followed by the intestine (9.91 µg/gtissue), muscle (6.20 µg/gtissue), gill (6.11 µg/gtissue), gonads (5.22 µg/gtissue) and brain (2.87 µg/gtissue). In the 40 mg/L treatment group (S2), the order of the tissue concentrations was similar to that of the S1 group, with the highest concentration observed in the liver (12.04 µg/gtissue), followed by the intestine (9.91 µg/gtissue), muscle (6.20 µg/gtissue), gill (6.11 µg/gtissue), gonads (5.22 µg/gtissue) and brain (2.87 µg/gtissue). Furthermore, the study detected 5-hydroxy-IMI, IMI urea and 6-chloronicotinic acid in IMI metabolites in all tissues, while IMI was detected only in the intestine and liver. Overall, the results of this study contribute to a better understanding of the metabolic behavior of IMI in organisms and provide new data to support the assessment of IMI toxicity in fish.

Interacted toxic mechanisms of ochratoxin A and tricyclazole on the zebrafish (Danio rerio).

Despite the current efforts to identify the mixtures of chemical pollutants, they are often "binned" into their corresponding pollutant groups. Limited studies have investigated complex mixtures of chemical pollutants co-occurring across different groups. The combined toxic impacts of several substances become a critical consideration in toxicology because chemical combinations can exert a greater deleterious effect than the single components in the mixture. In the current work, we assessed the joint impacts of ochratoxin A and tricyclazole on the zebrafish (Danio rerio) embryos and explored their underlying signaling pathways. Ochratoxin A displayed higher toxicity than tricyclazole, with a 10-day LC50 of 0.16 mg L-1, whereas that for tricyclazole was 1.94 mg L-1. The combination of ochratoxin A and tricyclazole exhibited a synergistic impact on D. rerio. The activities of detoxification enzymes GST and CYP450, as well as apoptosis-associated enzyme caspase 3, were distinctly changed in most individual and mixture exposures comparing to the untreated group. Upon both individual and mixture exposures, more dramatic variations were detected in the expressions of nine genes, such as the apoptosis genes cas3 and bax, antioxidant gene mn-sod, immunosuppression gene il-1ß, and the endocrine system genes trα, dio1, trß, ugtlab, and crh, compared with the untreated group. These findings suggested that the simultaneous exposure to low doses of mycotoxins and pesticides in food commodities was more toxic than predicted from the individual chemicals. Considering the frequent co-occurrence of mycotoxins and pesticides in the diet, this synergy should be considered in future assessments.

Dissipation and dietary exposure risk assessment of pyraclostrobin, fluxapyroxad, difenoconazole, and azoxystrobin in the Fritillaria field ecosystem.

Fritillaria (Beimu in Chinese) is a well-known traditional Chinese medicinal herbal and valuable health food, which has attracted more and more attention. In this study, an efficient method was developed to determine pyraclostrobin, fluxapyroxad, difenoconazole, and azoxystrobin in plants, fresh Fritillaria, dry Fritillaria, and soil via liquid chromatography-tandem mass spectrometry. The average recoveries of the method were 78.9-109.7% with relative standard deviations of 0.94-11.1%. The dissipation half-lives of the four fungicides were 4.4-7.7 days in the Fritillaria plant and 11.6-18.2 days in the soil. The terminal residues of four fungicides were 0.033-0.13 mg/kg in fresh Fritillaria, 0.096-0.42 mg/kg in dry Fritillaria, and 0.12-0.74 mg/kg in soil. In the risk assessment of dietary exposure, all the chronic hazard quotient and acute hazard quotient index values were far below 100%, which were both acceptable to consumers. Accordingly, 7 days was recommended as the pre-harvest interval for the four fungicides in Fritillaria. This work could guide the safe use of these fungicides in Fritillaria and also give a reference for the Chinese government to establish the maximum residue limits (MRLs).

Phosphine-Catalyzed Asymmetric Tandem Isomerization/Annulation of Allyl Amines with Allenoates: Enantioselective Annulation of a Saturated C-N Bond.

Under catalysis by chiral phosphine, an asymmetric isomerization/annulation cascade reaction of allylamines with allenoates was realized. A wide range of γ-substituted allenoates were tolerated to afford chiral pyrroline derivatives in high yields with excellent enantioselectivities. In the reaction, isomerization of readily available N-allylamines to reactive aliphatic imines through a 1,4-proton shift is a key step, which circumvents the isolation of highly unstable alkyl N-sulfonylimines.

Histology and multi-omic profiling reveal the mixture toxicity of tebuconazole and difenoconazole in adult zebrafish.

The combination effects of triazole fungicides on aquatic organisms remain largely unknown. In current study, an integrated histological, transcriptome, metabonomics and microbiology was applied to investigate the mixture effects and risk of tebuconazole (TEB) and difenoconazole (DIF) co-exposure on zebrafish liver and gonad at aquatic life benchmark. TEB and DIF mixture showed additive effect on the acute toxicity to adult zebrafish, the combined toxicity on liver was less than the additive effect of individual TEB and DIF, and TEB and DIF mixture also reduced the toxic effects on gonad and intestinal microflora. Transcriptomics and metabolomics further showed TEB and DIF mixture could induce more differentially expressed genes (DEGs) to regulate the metabolic pathways involved in energy metabolism, steroid hormone biosynthesis, retinol metabolism and microbial metabolism, to balance the energy metabolism and supplies, and maintain the steroid hormone and RA level, further reduced the toxic effect on liver and gonad caused by TEB and DIF. Our results showed the different responses and patterns on transcriptional and metabolic profiles mediated in the diverse toxicity and combination effects of TEB and DIF. The present results provided a deep mechanistic understanding of the combined effects and mode of action of DIF and TEB mixture on aquatic organisms, suggesting the concept of additive effects might sufficiently protective when evaluated the combination effects and ecological risk of TEB and DIF at aquatic life benchmarks.

Guadipyr, a new insecticide, induces microbiota dysbiosis and immune disorders in the midgut of silkworms (Bombyx mori).

Guadipyr, which combines neonicotinoid and semicarbazone functional groups in one molecule, exhibits good activity on several pests and high acute and chronic toxicity to silkworms (Bombyx mori). In this report, the effects of low-dose guadipyr on the midgut microbiota and immune system of silkworms were studied. Results showed that the structure and richness of the midgut microbiota of silkworms were altered after being treated with 5.25 mg/L (1/10 of LC50) of guadipyr. The abundance of Pseudomonas was evidently increased, whereas Curvibacter was substantially reduced, which might be related to the growth and immunity of silkworms. The expression of key genes in the Toll, IMD, and JAK/STAT pathways, which ultimately led to the downregulation of antimicrobial peptide genes (AMPs), such as CecA, Defensin1, Leb, and glv2, was reduced upon guadipyr exposure. Simultaneously, the suppression of steroid hormone 20-hydroxyecdysone receptor and response genes, such as BR-C Z4, was detected in the exposed groups. The decreased expression of these immune regulatory pathway-related and 20-hydroxyecdysone signal pathway-related genes indicated that the immune system of silkworms was affected by low-dose guadipyr. Our results revealed the negative effects of guadipyr on silkworms and highlighted the unneglectable toxicity of low-dose guadipyr to this economic insect. Given the risk, it is necessary to control the application of guadipyr in or around the mulberry fields.

Sorption, Desorption and Mobility of Microencapsulated Chlorpyrifos in Two Typical Soils.

The sorption, desorption, and mobility of microencapsulated chlorpyrifos (CPF-MC) in two typical soils, namely, silt loam and sandy, were investigated in this study. Sorption/desorption experiments were carried out by using the batch equilibration method. Results showed that the sorption isotherms of CPF-MC and emulsifiable concentrate of chlorpyrifos (CPF-EC) in silt loamy soil were similar. However, a considerable difference was observed in the sorption isotherms of two chlorpyrifos (CPF) formulations in sandy soil. The amounts of CPF desorbed from two soils in four desorption steps decreased sequentially in CPF-EC treatments, while the desorbed amounts remained stable in CPF-MC treatments. Hence, the sorption/desorption processes of CPF-EC were mainly controlled by soil affinity to CPF. However, these processes of CPF-MC were affected by the release rate of CPF from capsules. The mobility of two CPF formulations in soil was estimated in vertical columns packed with soils. Results showed that there was leaching of CPF-EC in silt loam column, whereas CPF-MC was not vertically mobile in silt loam column under the same leaching conditions. However, in column with sandy soil, the percentage of CPF-MC leaching from the column was 86.54%, which was higher than the 73.75% that leached from the column in the treatment with CPF-EC.

Residue behavior and risk assessment of validamycin a in grape under field conditions.

The dissipation and residue of validamycin A in grapes were investigated under field conditions. An ultra-high performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) method for the determination of validamycin A in grapes was established and validated. Methanol and water (90/10, v/v) were used for validamycin A extraction and purification used MCX solid-phase extraction cartridges. The average recoveries of validamycin A in grapes at 0.01, 0.50, and 5.0 mg/kg levels were between 83.8 and 91.4%, with relative standard deviations of 2.3-3.0%. The half-lives of validamycin A in grape were 4.4-6.1 days. The terminal residues in grapes over a range of harvest times (7, 14, and 21 days) were no more than 0.73 mg/kg. According to Chinese consumption data, the risk quotient (RQ) of validamycin A was 3.22%, demonstrating a low risk to consumers. The current study may offer guidance for validamycin A use and could aid the government in determining the maximum residue level (MRL) values for validamycin A in grapes.

Effects of difenoconazole on hepatotoxicity, lipid metabolism and gut microbiota in zebrafish (Danio rerio).

In current study, larvae and adult zebrafish were exposed to difenoconazole to assess its effect on hepatotoxicity, lipid metabolism and gut microbiota. Results demonstrated that difenoconazole could induce hepatotoxicity in zebrafish larvae and adult, 0.400, 1.00, 2.00 mg/L difenoconazole caused yolk retention, yolk sac edema or liver degeneration after embryos exposure for 120 h, hepatocyte vacuolization and neoplasm necrosis were observed in adult liver after 0.400 mg/L difenoconazole exposure for 21 d. RNA sequencing showed that the 41 and 567 differentially expressed genes in zebrafish larvae and liver induced by 0.400 mg/L difenoconazole, were concentrated in pathways related to protein digestion and absorption, pancreatic secretion, steroid biosynthesis, and different metabolic pathways including galactose or sugar metabolism. Difenoconazole exposure caused lipid accumulation in larval yolk sac, and the elevated triglyceride (TG), malondialdehyde (MDA) and reactive oxygen species (ROS) levels in larvae and liver, which further confirmed the lipid metabolism disorders induced by difenoconazole. The results further showed that difenoconazole increased the abundance of gut microbiota such as Firmicutes, Aeromonas, Enterobacteriaceae and Bacteroides, further suggested that gut microbiota might participate in lipid metabolism and hepatotoxicity during zebrafish development. These findings advanced the field of the difenoconazole-induced developmental toxicity in larvae and adult zebrafish, and the imbalance of gut microbiota provided the plausible mode of action for the liver damage and disordered lipid metabolism in zebrafish.

Dissipation behavior, residue distribution, and risk assessment of triflumizole and FM-6-1 in greenhouse strawberries and soil.

This study aimed to develop a reliable method for the simultaneous analysis of triflumizole (TRIF) and its primary metabolite FM-6-1 (N-4-chloro-2-trifluoromethylphenyl-2-propoxy-acetamidine) in the soil and treated strawberries using solid phase extraction (SPE) coupled with gas chromatography-tandem mass spectrometry (GC-MS/MS). Using this method, TRIF and FM-6-1 degradation in strawberries and the soil under greenhouse conditions were investigated. The field trials showed that t1/2 of TRIF and total residues (the sum of TRIF and FM-6-1) were 1.6-2.2 days and 2.4-2.9 days in strawberry and 4.3-6.1 days and 5.5-6.9 days in soil, respectively. Terminal total residues were ≤ 0.39 mg/kg in strawberry and ≤ 0.42 mg/kg in soil from 5 to 10 days of harvest. The risk quotient (RQ) of TRIF was below 1.89%, showing that the dietary risk of TRIF in strawberry was low. These findings provide guidance for the use of TRIF on crops and provide reference to establish the maximum residue level (MRL) of TRIF in strawberry.

Mitochondrial dysfunction, apoptosis and transcriptomic alterations induced by four strobilurins in zebrafish (Danio rerio) early life stages.

Though the toxicity of strobilurins on non-target aquatic organisms has been characterized, the associated toxic mechanisms have not been fully explored. The present study showed that the larval stage was the most sensitive developmental stage in zebrafish, and pyraclostrobin (PY) had the highest acute toxicity to embryos, larvae, juvenile and adult with 96 h-LC50 at 0.048 mg/L, 0.029 mg/L, 0.039 mg/L, 0.031 mg/L respectively, when compared with the toxicity of trifloxystrobin (TR), kresoxim-methyl (KM) and azoxystrobin (AZ) at corresponding developmental stage. Then we investigated the transcriptomics and developmental toxicity of TR, KM, AZ and PY on zebrafish embryos after 72 h exposure. RNA-seq revealed that the pathways related to cell apoptosis and cancer, and cellular components organelle membrane and mitochondrion, were markedly affected after TR, KM, AZ and PY exposure during zebrafish early life stages. The results were further confirmed by the induction of antioxidant enzymes catalase (CAT) and superoxide dismutase (SOD) activities, the elevation of H2O2, malondialdehyde (MDA) and reactive oxygen species (ROS) level, as well as the reduction of intracellular calcium ions (Ca2+) and mitochondrial membrane potential (MMP), which indicated that strobilurins could cause mitochondrial dysfunction and cell apoptosis. The present study was performed a systematic analysis of strobilurins to zebrafish at multi-levels, which provided suggestions for further investigation of molecular mechanisms underlying the toxicity induced by strobilurins on aquatic organisms.

Toxicological analysis of triadimefon on endocrine disruption and oxidative stress during rare minnow (Gobiocypris rarus) larvae development.

Triadimefon (TDF) is a systemic wide-spectrum antifungal compound that is widely used in agriculture to inhibit fungal growth on various crops. Since previous studies focused on the embryo and adult life stages in the investigation of ecological impact, here we investigated the long-term effects of TDF (1, 10, 100 µg/L) on rare minnow during its larvae development. TDF caused an anti-estrogenic effect by decreasing vitellogenin (VTG) and CYP19a mRNA level, and inhibiting the aromatase activity and VTG levels after a 3, 6, 10, or 14-day exposure in rare minnow larvae. TDF also disturbed the endocrine disruption by regulating the transcription of estrogen receptors ERα, ERß1 and ERß2, CYP1a, CYP11, CYP17, steroidogenic acute regulator (STAR), doublesex and mab-3 related transcription factor (DMRT1), gonadotropin-releasing hormone (GnRH2), GnRH3, GnRHR1A, and GnRHR1B. Furthermore, TDF induced the accumulation of reactive oxygen species (ROS) and the activity of antioxidant proteins glutathione peroxidase (GPX), superoxide dismutase (SOD), and catalase (CAT), and significantly increased the transcriptions of stress response genes P53, growth arrest and DNA damage-inducible 45 alpha (Gadd45α), and COX1, suggested that TDF might cause oxidative stress during larvae development. The changes in transcript and biological levels represented the potential adaptive or compensatory responses to impaired oxidative stress and endocrine system after TDF exposure in rare minnow during its larvae development.

The toxic influence of paraquat on hippocampal neurogenesis in adult mice.

Paraquat, a fast-acting non-selective contact herbicide, is considered an etiological factor related to Parkinson's disease. This study investigated its effects on hippocampal neurogenesis and cognition in adult mice as well as possible mechanisms for the effects. We administered paraquat (1.25 mg/kg, intraperitoneal injection, i.p.) and an equal volume of normal saline for 3 weeks to adult male C57BL/6J mice. The results showed that hippocampus-dependent spatial learning and memory was significantly impaired in paraquat-treated mice. Moreover, paraquat administration inhibited the proliferation of neural progenitor cells, and impaired the survival and altered the fate decision of newly generated cells in the hippocampus. The expression levels of caspase-3 and glial fibrillary acidic protein were significantly higher in paraquat-treated mice than in control mice. Interestingly, paraquat reduced the phosphorylation of Akt, but did not affect the total amount of Akt. In conclusion, our findings suggest that paraquat negatively affected adult hippocampal neurogenesis and cognition function.

Field investigations of dissipations and residues of cyazofamid in soil and tomato: risk assessment of human exposure to cyazofamid via tomato intake.

Cyazofamid, as a fungicide of the novel cyanoimidazole chemical class, has been widely used to control tomato late blight. Understanding of cyazofamid residues in environment and crops is an essential prerequisite for its risk assessment. In this study, field investigations in four typical tomato-producing areas were conducted to explore the dissipation kinetics and residues of cyazofamid and its primary metabolite 4-chloro-5-p-tolylimidazole-2-carbonitrile (CCIM) in soil and tomato. A robust method using QuEChERS coupled with liquid chromatography-tandem mass spectrometry (LC-MS/MS) was developed for simultaneous analysis of cyazofamid and CCIM, with limits of quantification of 0.33 and 3.8 µg/kg, respectively. Field trials showed that the half-lives of cyazofamid were 3.6-6.9 days in soil and 12.2-18.3 days in tomato. The total residues of cyazofamid and CCIM in tomato collected at three time intervals were all below 0.5 mg/kg. Moreover, the potential risks of total residues via tomato intake to ten population subgroups were evaluated. We found that the risk quotient values were all generally low (0.13-1.3%), indicating that the recommended dose of cyazofamid on tomato will not result in a consumer exposure exceeding the toxicological reference value. Here, the results of field investigation provided important information for further understanding the behavior and risk of cyazofamid in the natural environment.