Combined toxic effects of polyethylene microplastics and lambda-cyhalothrin on gut of zebrafish (Danio rerio).

Microplastics (MPs), which are prevalent and increasingly accumulating in aquatic environments. Other pollutants coexist with MPs in the water, such as pesticides, and may be carried or transferred to aquatic organisms, posing unpredictable ecological risks. This study sought to assess the adsorption of lambda-cyhalothrin (LCT) by virgin and aged polyethylene MPs (VPE and APE, respectively), and to examine their influence on LCT's toxicity in zebrafish, specifically regarding acute toxicity, oxidative stress, gut microbiota and immunity. The adsorption results showed that VPE and APE could adsorb LCT, with adsorption capacities of 34.4 mg∙g-1 and 39.0 mg∙g-1, respectively. Compared with LCT exposure alone, VPE and APE increased the acute toxicity of LCT to zebrafish. Additionally, exposure to LCT and PE-MPs alone can induce oxidative stress in the zebrafish gut, while combined exposure can exacerbate the oxidative stress response and intensify intestinal lipid peroxidation. Moreover, exposure to LCT or PE-MPs alone promotes inflammation, and combined exposure leads to downregulation of the myd88-nf-κb related gene expression, thus impacting intestinal immunity. Furthermore, exposure to APE increased LCT toxicity to zebrafish more than VPE. Meanwhile, exposure to PE-MPs and LCT alone or in combination has the potential to affect gut microbiota function and alter the abundance and diversity of the zebrafish gut flora. Collectively, the presence of PE-MPs may affect the toxicity of pesticides in zebrafish. The findings emphasize the importance of studying the interaction between MPs and pesticides in the aquatic environment.

Effects of single and combined exposure of virgin or aged polyethylene microplastics and penthiopyrad on zebrafish (Danio rerio).

The interaction between pesticides and microplastics (MPs) can lead to changes in their mode of action and biological toxicity, creating substantial uncertainty in risk assessments. Succinate dehydrogenase inhibitor (SDHI) fungicides, a common fungicide type, are widely used. However, little is known about how penthiopyrad (PTH), a member of the SDHI fungicide group, interacts with polyethylene microplastics (PE-MPs). This study primarily investigates the individual and combined effects of virgin or aged PE-MPs and penthiopyrad on zebrafish (Danio rerio), including acute toxicity, bioaccumulation, tissue pathology, enzyme activities, gut microbiota, and gene expression. Short-term exposure revealed that PE-MPs enhance the acute toxicity of penthiopyrad. Long-term exposure demonstrated that PE-MPs, to some extent, enhance the accumulation of penthiopyrad in zebrafish, leading to increased oxidative stress injury in their intestines by the 7th day. Furthermore, exposure to penthiopyrad and/or PE-MPs did not result in histopathological damage to intestinal tissue but altered the gut flora at the phylum level. Regarding gene transcription, penthiopyrad exposure significantly modified the expression of pro-inflammatory genes in the zebrafish gut, with these effects being mitigated when VPE or APE was introduced. These findings offer a novel perspective on environmental behavior and underscore the importance of assessing the combined toxicity of PE-MPs and fungicides on organisms.

Multi-walled carbon nanotubes enhance the toxicity effects of dibutyl phthalate on early life stages of zebrafish (Danio rerio): Research in physiological, biochemical and molecular aspects.

Phthalate esters (PAEs) are widely used as plasticizers. PAEs are ubiquitous in natural water bodies, with dibutyl phthalate (DBP) being one of the most common PAEs. DBP is prone to leaching or migration into the environment, posing serious health and environmental risks. Carbon nanotubes (CNTs) have been widely used in various fields with the rapid development of nanotechnology. CNTs could alter the environmental behavior and toxicity of co-existing pollutants. CNTs have been shown to rapidly adsorb PEAs. However, current knowledge about the effects of CNTs on DBP toxicity is limited. Here we show that the toxic effects of single and combined exposure to DBP (0.1, 0.5, 1.0 mg/L) and different CNTs (MWCNTs/MWCNTs-COOH, 0.5 mg/L) on the early growth stage of zebrafish. The results suggested that a significant increase in heart rate and heart malformation rate was observed after co-exposure of DBP and MWCNTs/MWCNTs-COOH (p < 0.05). Furthermore, combined exposure increased antioxidant enzyme activity during early developmental stages in zebrafish (p < 0.05). The qRT-PCR results revealed that DBP and MWCNTs/MWCNTs-COOH co-exposure significantly interfered with the expression of genes related to oxidative stress, energy metabolism, development of cardiac function, and apoptosis (p < 0.05). In addition, for oxidative stress and cardiotoxicity, MWCNTs/MWCNTs-COOH aggravated the toxic effects of 0.5 mg/L DBP on embryos/larvae. The metabolomics results showed that co-exposure mitigated the disturbance of amino acid metabolism mediated by single DBP exposure. In general, MWCNTs/MWCNTs-COOH increased the impact of DBP in the early developmental stages of zebrafish. This study provides new insights into the toxicology of early developmental stages of aquatic organisms exposed to co-exist pollutants of DBP and CNTs.

Single and combined effects of polyethylene microplastics and acetochlor on accumulation and intestinal toxicity of zebrafish (Danio rerio).

The co-exposure of microplastics (MPs) and other contaminants has aroused extensive attention, but the combined impacts of MPs and pesticides remain poorly understood. Acetochlor (ACT), a widely used chloroacetamide herbicide, has raised concerns for its potential bio-adverse effects. This study evaluated the influences of polyethylene microplastics (PE-MPs) for acute toxicity, bioaccumulation, and intestinal toxicity in zebrafish to ACT. We found that PE-MPs significantly enhanced ACT acute toxicity. Also, PE-MPs increased the accumulation of ACT in zebrafish and aggravate the oxidative stress damage of ACT in intestines. Exposure to PE-MPs or/and ACT causes mild damage to the gut tissue of zebrafish and altered gut microbial composition. In terms of gene transcription, ACT exposure triggered a significant increase in inflammatory response-related gene expressions in the intestines, while some pro-inflammatory factors were found to be inhibited by PE-MPs. This study provides a new perspective on the fate of MPs in the environment and on the assessment of the combined effects of MPs and pesticides on organisms.

Enantioselective toxic effects of the novel chiral antifungal agrochemical penthiopyrad in the early life stage of zebrafish (Danio rerio).

Penthiopyrad was extensively applied in agricultural production, however, the toxicities information of the penthiopyrad enantiomers on early life stages of aquatic organism were limited. This study investigated the enantioselective toxicity of penthiopyrad on the early life stage of zebrafish by acute toxicity, sublethal toxic effects and the mRNA relative expression levels of genes related to succinate dehydrogenase, cardiac development, and lipid metabolism. The results showed that the 96-h-LC50 of penthiopyrad racemate and enantiomers to zebrafish embryos were Rac-: 2.784 mg/L; R-(-)-: 3.528 mg/L; S-(+)-: 1.882 mg/L. Penthiopyrad exposure induced autonomous movement abnormalities, slowed heart rate and delayed hatching in zebrafish embryos, and caused developmental toxic effects such as pericardial edema and yolk sac edema. The mRNA relative expression levels results showed that penthiopyrad exposure induced significant enantioselectivity effect for the expression of the Sdha, Pr1 and Nkx2.5 with a 1.94-4.98-fold difference between different enantiomers, and significantly affected succinate dehydrogenase (energy metabolism), lipid metabolism and cardiac development-related genes expression. In general, S-(+)-penthiopyrad induced higher toxic effects in zebrafish embryos, and mitochondrial dysfunction may be an important cause of abnormal development. This study contributed to improve the comprehensive risk assessment and enantiomeric research system of penthiopyrad to early life stage of zebrafish.

Enantioselective toxic effects of mefentrifluconazole in the early life stage of zebrafish (Danio rerio).

The research on the enantioselective toxic effects of chiral pesticides on non-target aquatic organisms has attracted more and more attention. This study investigated the enantioselective toxic effects of mefentrifluconazole (MFZ) on acute toxicity, developmental toxicity, locomotor behaviors, and the mRNA relative expression levels of genes related to neurodevelopment and cardiac development in zebrafish embryos or larvae. The 96-h lethal concentration 50 (LC50 ) values (exposed to racemate and enantiomers of MFZ, that is, rac-MFZ/(-)-MFZ/(+)-MFZ) were 1.010, 1.552, and 0.753 mg/L for embryo, and 0.753, 1.187, and 0.553 mg/L for larvae. The rac-MFZ/(-)-MFZ/(+)-MFZ can affect the heart development of zebrafish embryos, accompanied by heart rate inhibition, yolk sac deformities, pericardial deformities, and down-regulation of genes related to cardiotoxicity in larvae in an enantioselective manner. Moreover, the rac-MFZ/(-)-MFZ/(+)-MFZ also can affect the neural development of zebrafish embryos, accompanied by autonomic movement inhibition, swimming speed and swimming distance abnormalities, and down-regulation of genes related to neurotoxicity in larvae in an enantioselective manner. For all toxicity endpoints, the effect of the (+)-MFZ to early-staged zebrafish were significantly greater than that of (-)-MFZ. These results will help distinguishing the difference of MFZ enantiomers to zebrafish, and provide scientific reference for improving the risk assessment of chiral pesticides MFZ.

Multi-walled carbon nanotubes impact on the enantioselective bioaccumulation and toxicity of the chiral insecticide bifenthrin to zebrafish (Danio rerio).

The effects of different multi-walled carbon nanotubes on the enantioselective bioaccumulation and toxicity of the chiral pesticide bifenthrin to zebrafish were investigated in this work. The results showed that MWCNTs and MWCNTs-COOH did not affect the preferential bioaccumulation of 1R-cis-BF in zebrafish following exposure to cis-BF enantiomers for 28 days, but which increased cis-BF accumulation amount by 1.03-1.48 times. Further research demonstrated that the genes related to immunity, endocrine activity and neurotoxicity showed enantioselective expression in different zebrafish tissues, and sex-specific differences were observed. The levels of c-fos, th, syn2a, 17ß-hsd and cc-chem were expressed as 1.09-2.84 times higher in females and males treated with 1R-cis-BF than in the 1S-cis-BF-treated groups. However, in the presence of MWCNTs or MWCNTs-COOH, c-fos, th, syn2a, 17ß-hsd and cc-chem levels were expressed as 1.53-14.92 times higher in females and males treated with 1S-cis-BF than in 1R-cis-BF-treated groups, which indicated that enantioselective expression was altered. The effects of different types of MWCNTs on the enantioselective bioaccumulation and toxicity of BF in zebrafish have little difference. In summary, the presence of MWCNTs or MWCNTs-COOH increased the impact of BF on zebrafish. Therefore, the risks posed by coexisting nanomaterials and chiral pesticides in aquatic environments should be considered.

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.

Enantioselective bioaccumulation and toxicity of the novel chiral antifungal agrochemical penthiopyrad in zebrafish (Danio rerio).

Succinate dehydrogenase inhibitor (SDHI) fungicides has been extensively used in agricultural production, which are not easily degrade in the environment and have various toxic effects on aquatic organisms. However, the toxic effects information to non-target organisms were mostly at the racemate level, which were poorly understood at the enantiomers level. Thus, this study aimed to investigate the enantioselective bioaccumulation behavior and toxic effects of penthiopyrad in zebrafish. Significant enantioselective bioaccumulation was observed when exposed to penthiopyrad at two dose levels: S-(+)-penthiopyrad was preferentially accumulated. Moreover, S-(+)-penthiopyrad caused oxidative stress in zebrafish liver. The results of real-time RT-PCR analyses revealed that exposure to penthiopyrad also enantioselectivity interfered with the expression of mitochondrial respiratory complexes, mtDNA synthesis, lipid metabolism and apoptosis-related genes. S-(+)-penthiopyrad significantly decreased most of the expression of the above gene, which showed higher toxic effects. We inferred that the toxicity mechanism of penthiopyrad was caused by lipid metabolism disorder and mitochondrial dysfunction in zebrafish, and further leads to apoptosis even DNA damage. This study provides more accurate data to investigate the environmental impact of penthiopyrad at the enantiomer level.

[Preparation and performance evaluation of a novel polar urea-propyl-C30 stationary phase].

A novel polar urea-propyl-C30 (TPU-C30) reversed stationary phase was prepared by using 3-ureidopropyltrimethoxysilane as a coupling agent. The characteristics of TPU-C30 were analyzed by scanning electron microscopy, elemental analysis, infrared spectroscopy and thermal analysis. The results showed that the TPU-C30 stationary phase was successfully prepared. Furthermore, the relative deviations of the element contents of TPU-C30 were within 5% (n=3), which indicated that the proposed synthesis had good repeatability. The chromatographic performances in the stationary phase were evaluated by using different polar compounds, positional isomers and basic compounds as solute probes. Compared to the conventional C18 and C30 columns, the TPU-C30 stationary phase had different selectivity and better shape selection. The TPU-C30 stationary phase can be applied in various fields.

Facile Synthesis and Chiral Separation of Chiral Mesoporous Silica Microspheres.

Mesoporous silica microspheres were synthesized by an acid-catalyzed sol-gel method using tetraethoxysilane (TEOS) as a precursor. The hydrochloric acid was used as a catalyzer to induce the hydrolysis of TEOS, while the cyclohexane acted as a stabilizer of the sol. The addition of polyethylene glycol can introduce the uniform mesoporous structure into the microspheres by phase separation. The as-prepared mesoporous silica microspheres possess a narrow particle size distribution, a mesopore size of 5.0 nm and a Brunauer-Emmett-Teller specific surface area as high as 230 m2·g-1. The resultant silica microspheres were used for packing chiral high-performance liquid chromatography (HPLC) columns, after activated by hydrochloric acid and modified by amylose-tris(3,5-dimethylphenylcarbamate), respectively. The flurbiprofen axetil as a typical chiral drug with two stereocenters can be successfully separated by the as-obtained chiral HPLC columns using different mobile phases.

[Determination of triterpenoic acid isomers in Eriobotryae folium using high performance liquid chromatography on C30 column].

A rapid and easy assay method for four triterpenoic acid isomers in Eriobotryae folium was established. The sample was extracted with methanol, then separated on a C30 column (250 mm x 4.6 mm, 5 microm) at 20 degrees C using acetonitrile-water (95 : 5, v/v) as the mobile phase at a flow rate of 1.0 mL/min. The target compounds were simultaneously detected at 210 nm, and the injection volume was 10 microL. The validation was carried out and the resolution (R > or = 2.2), the precision (RSD < or = 1.1%), the linearity (r > or = 0.999 2), the repeatability (RSD < or = 4.4%), and the recovery (range from 95.4% to 101.7%, RSD < or = 4.8%) were acceptable. The method is reliable for the quantification of the four triterpenoic acid isomers by HPLC on C30 column.