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•α-Amylase-responsive carrier was fabricated using HMS and α-CD as shell materials.•The release of AVM from AVM-CRF was specifically triggered via α-amylase.•AVM-CRF was more stable ...under UV irradiation than AVM technical.•Toxicity of AVM-CRF to P. xylostella is significant stronger than that of AVM-CF.
α-Amylase-responsive carrier for controlled release of avermectin (AVM) was prepared based on α-cyclodextrin (α-CD) anchored hollow mesoporous silica (HMS) using α-CD as a capping molecule. The release of AVM was studied at different temperatures, pH values and in the presence or absence of α-amylase. The results revealed that the AVM-encapsulated controlled release formulation (AVM-CRF) has a drastic enzymatic dependence, an excellent encapsulation efficacy reaching 38%, and outstanding UV and thermal shielding ability. The AVM-CRF biological activity survey shows excellent toxicological properties against Plutella xylostella larvae, which confirms that α-CD caps could be uncapped enzymatically in vivo and release AVM, inducing P. xylostella larval death. AVM-CRF has a notable capability to keep 0.6 mg L−1 AVM biologically active until 14th day with 83.33% mortality of the target insect, which was 40% higher than that of treated with AVM commercial formulation. The study provides a theoretical basis for the application of pesticide reduction.
In the present study, enzymatic responsive controlled release formulations (CRFs) were fabricated. The CRFs were achieved by anchoring mechanically interlocked molecules using α-cyclodextrin onto the ...surface pore rims of hollow mesoporous silica (HMS). The CRFs were characterized using Fourier transform infrared spectroscopy, scanning electron microscopy, transmission electron microscopy, and thermogravimetric analysis. The results showed that the CRFs had extraordinary loading ability for chlorantraniliprole (42% w/w) and could effectively preserve chlorantraniliprole against degradation under thermal conditions and UV radiation. The CRFs have been proven to be enzyme-sensitive. The release ratio of chlorantraniliprole from CRFs can be accelerated observably when external α-amylase was introduced. The persistence of CRFs was evaluated by regular sampling feeding experiment using Plutella xylostella as the target insect. The results showed that the larval mortality of P. xylostella was much higher than that of Coragen under all concentrations after 14 days, which proved that CRFs had remarkable persistence.
Understanding the lethal effects of pesticides nano formulations on the targeted organisms (pathogens) and the non-targeted organisms (fish, earthworms, etc) is essential in assessing the probable ...impact of new technologies on agriculture and environment. Here we evaluated the bioactivity and the biotoxicity of new type of fungicide smart-delivery formulation based on conjugating carboxymethylated-β-glucans on the mesoporous silica nanoparticles (MSNs) surface after loading chlorothalonil (CHT) fungicide in the MSNs pores. The obtained formulation has been characterized with FE-SEM, and HR-TEM. The CHT loading efficiency has been measured with TGA. The bioactivity of the obtained formulation (CHT@MSNs-β-glucans) has been tested against four pathogens, fusarium head blight (Fusarium graminearum), sheath rot (Sarocladium oryzae), rice sheath blight (Rhizoctonia solani), and soyabean anthracnose (Colletotrichum truncatum) compared with CHT WP 75% commercial formulation (CHT-WP) and technical CHT. The environmental biotoxicity of CHT@MSNs-β-glucans compared with CHT-WP has been tested toward earthworm (Eisenia fetida) and zebra fish (Danio rerio). The results showed that CHT@MSNs-β-glucans has an excellent bioactivity against the subjected pathogens with better inhabiting effects than CHT-WP. CHT@MSNs-β-glucans toxicity to Eisenia fetida was found 2.25 times lower than CHT-WP toxicity. The LC50 of CHT@MSNs-β-glucans to zebra fish after the first 24h was 2.93 times higher than CHT-WP. After 96h of treatment, the LC50 of CHT@MSNs-β-glucans was 2.66 times higher than CHT-WP. This work highlighted the necessity to increase the mandatory bioassays of nano formulations with the major non-target organisms in the environmental risk assessment of new pesticide formulations.
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•In vitro bioassays used to assess toxicity of CHT-WP vs. CHT@MSNs-β-glucans.•CHT@MSNs-β-glucans bioactivity against pathogens is better than CHT-WP.•CHT@MSNs-β-glucans has lower toxicity to Eisenia fetida than CHT-WP.•CHT@MSNs-β-glucans has lower toxicity to zebra fish.•CHT@MSNs-β-glucans possessed good biocompatibility and biosafety.
Fosthiazate is a widely used chiral organophosphorous nematicide with four stereoisomers. The present study systemically assessed the stereoselectivity of fosthiazate for the first time, including ...absolute configuration confirmation, stereoselective bioactivity toward nematode and aphid, toxicity to honeybees, and stereoselective degradation in cucumber and pepper under field conditions. The absolute configurations of the four stereoisomers that eluted on the Superchiral IG-3 column were confirmed as (1S,3R)-(−)-fosthiazate, (1S,3S)-(−)-fosthiazate, (1R,3S)-(+)-fosthiazate, and (1R,3R)-(+)-fosthiazate. In comparison to the other two stereoisomers, (1S,3R)-fosthiazate and (1S,3S)-fosthiazate possess more than 100 times bioactivity and 10 times toxicity toward the target and non-target organisms, respectively. The molecular docking found that (1S,3R)-fosthiazate and (1S,3S)-fosthiazate had shorter binding distances and lower energies with acetylcholinesterase (AChE), which illuminated the mechanism of the experimental results. In addition, both of the high-bioactive stereoisomers had faster degradation rates in cucumber and pepper. On the basis of the results of bioactivity, toxicity, and degradation behavior, the stereoisomer mixture with (1S,3R)-fosthiazate and (1S,3S)-fosthiazate will be a better option than racemic fosthiazate to increase the bioactivity and reduce application rates.
Controlled release formulation of pesticides is a highly desirable way to increase the efficiency of the pesticide as well as help reduce environmental pollution issues. In the present study, a novel ...adhesive organic-inorganic hybrid material with a uniform size and morphology was fabricated employing hollow mesoporous silica (HMS) as an inlayer material and poly(diacetone acrylamide) (PDAAM) as an outer layer material. HMS was fabricated using polystyrene (PS) spheres as a hard template. Then, HMS was functionalized with 3-aminopropyltriethoxysilane and 2-bromoisobutyryl bromide after removal of PS. Finally, PDAAM was grafted onto HMS using surface-initiated atom transfer radical polymerization. Cyantraniliprole (CNAP) utilized as a model pesticide was incorporated into hybrid material to prepare controlled release formulation. The results showed that both CNAP−loaded HMS and HMS−PDAAM had extraordinary loading efficiencies (approximately 50% w/w). Kinetic studies of CNAP release demonstrated that CNAP−loaded HMS−PDAAM exhibited a sustained release property for at least 25 days. The stability test identified that CNAP−loaded HMS and HMS−PDAAM were much more stable under UV irradiation and thermal conditions than CNAP technical. Tests of the adhesive properties showed that the adhesive property of HMS−PDAAM was far stronger than that of HMS on rice leaves. Given the advantages of HMS−PDAAM, this hybrid material may be applied to other photosensitive pesticides, especially those used for foliar spraying.
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•A novel hybrid material was fabricated employing HMS and PDAAM as shell materials.•CNAP-loaded HMS@PDAAM exhibited a sustained release property.•CNAP-loaded HMS@PDAAM was more stable under UV irradiation than CNAP technical.•HMS@PDAAM showed far stronger adhesive property than that of HMS on rice leaves.
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•S,R-epoxiconazole degradation in soil and water is faster than R,S-epoxiconazole.•S,R-epoxiconazole is toxic for Chlorella vulgaris than R,S-epoxiconazole.•R,S-epoxiconazole is toxic ...for Daphnia magna than S,R-epoxiconazole.•R,S-epoxiconazole bioactivity to plant pathogens is higher than S,R-epoxiconazole.
To clarify the environmental behaviour and bioactivity of epoxiconazole enantiomers, an integrated assessment has been done. The degradation in soil, water, and river-sediments were studied. The toxicity to Chlorella vulgaris and Daphnia magna was also examined. The bioactivity to plant-pathogens and molecular docking to CYP51 were investigated. The obtained results showed that the half-lives of R,S-(+)- and S,R-(-)-epoxiconazole were 38.8 and 21.2 days in Jiangsu soil, 43.2 and 22.7 days in Jiangxi soil, 29.1 and 21.3 days in Jilin soil, 43.5 and 32.7 days in anaerobic Jilin soil, 12.3 and 10.1 days in river sediments, and 33.2 and 9.3 days in river water, respectively. Maximum EF was 0.36 in Yangzi-river water. No enantioselective degradation was found in sterilized conditions. The EC50 to C. vulgaris after 48 h was 27.78 mg L−1, and 18.93 mg L−1 for R,S-(+)-, and S,R-(-)-epoxiconazole, respectively. The LC50 to D. magna was 4.16 mg L−1, and 8.49 mg L-1 for R,S-(+)-, and S,R-(-)-epoxiconazole, respectively. R,S-(+)-epoxiconazole bioactivity was 1.3–7.25 times higher than S,R-(-)-epoxiconazole. In conclusion, R,S-(+)- has higher bioactivity and higher environmental toxicity. In opposite, S,R-(-)- has lower environmental toxicity and lower bioactivity. R,S-(+)-epoxiconazole use is recommended with lower concentrations, which is appropriate for environment safety.
In this study, pH-responsive LC@O-CMCS/PU nanoparticles were prepared by encapsulating λ-cyhalothrin (LC) with O-carboxymethyl chitosan (O-CMCS) to form LC/O-CMCS and then covering it with ...polyurethane (PU). Characterization and performance test results demonstrate that LC@O-CMCS/PU had good alkaline release properties and pesticide loading performance. Compared to commercial formulations containing large amounts of emulsifiers (e.g., emulsifiable concentrate, EC), LC@O-CMCS/PU showed better leaf-surface adhesion. On the dried pesticide-applied surfaces, the acute contact toxicity of LC@O-CMCS/PU to Harmonia axyridis (H. axyridis) was nearly 20 times lower than that of LC EC. Due to the slow-releasing property of LC@O-CMCS/PU, only 16.38 % of LC was released at 48 h in dew and effectively reduced the toxicity of dew. On the pesticide-applied leaves with dew, exposure to the LC (EC) caused 86.66 % mortality of H. axyridis larvae significantly higher than the LC@O-CMCS/PU, which was only 16.66 % lethality. Additionally, quantitative analysis demonstrated 11.33 mg/kg of λ-cyhalothrin in the dew on LC@O-CMCS/PU lower than LC (EC) with 4.54 mg/kg. In summary, LC@O-CMCS/PU effectively improves the safety of λ-cyhalothrin to H. axyridis and has great potential to be used in pest control combining natural enemies and chemical pesticides.
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In this study, a pesticide controlled release system with dual response characteristics of pH and enzyme triggering was developed. Indoxacarb (IDC) was loaded into hollow mesoporous silica (HMS) ...nanoparticles, carboxylated β-cyclodextrin (β-CD) acted as a capping molecule to couple with the amino-functionalized HMS, and their well-defined morphological structures were confirmed by scanning electron microscopy and transmission electron microscopy. The results showed that the prepared IDC loaded HMS-CD had high loading efficiency (26.42%, w/w) and showed excellent dual response properties to pH and the α-amylase enzyme. IDC loaded HMS-CD nanoparticles showed better insecticidal activity against Spodoptera frugiperda than applying the same dose of IDC emulsifiable concentrate, and the toxicity of IDC loaded HMS-CD to zebrafish was reduced by more than 5-fold, indicating that insecticide delivery systems based on β-CD-anchored HMS nanoparticles could potentially be applied for sustainable control of pests and reduce harm to non-target organisms and the environment.
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•A stimuli-responsive carrier was fabricated employing β-CD as the gatekeeper of HMS.•IDC loaded HMS-CD displayed excellent dual-responsive α-amylase and pH properties.•The prepared IDC loaded HMS-CD had good UV radiation stability.•The IDC loaded HMS-CD had a longer duration of excellent insecticidal activity.•The IDC loaded HMS-CD was significantly less toxic to zebrafish than IDC EC.
The wide use of chiral fungicides has generated interest in the stereoselectivity of their ecotoxicological effects. However, there are few studies about the potential endocrine-disrupting effects ...(EDEs) of chiral fungicides. This study evaluated the hormone receptor activities of the chiral triazole fungicide prothioconazole and its metabolite using reporter gene assays. The results indicated that prothioconazole and its metabolite possessed EDEs, and the metabolite exerted more activities than the activities of the parent compound, suggesting that the metabolic process is toxification. Stereoselective EDEs were observed, and the S-enantiomers possessed greater hormonal effects than those possessed by the R-enantiomers; the REC20 values ranged from 7.9 × 10−10 to 6.4 × 10−7 M for the thyroid hormone effects and from 3.2 × 10−9 to 7.8 × 10−8 M for the estrogenic effects. The molecular docking results revealed that the stereoselective EDEs of prothioconazole and its metabolite were partially attributed to enantiospecific receptor binding affinities. Overall, our results reveal that prothioconazole and its metabolite might disrupt the balance of the endocrine system by affecting the function of multiple nuclear hormone receptors and that they have the potential to affect the developmental and reproductive systems in humans.
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•Prothioconazole and its metabolite exerted endocrine-disrupting effects.•The metabolite possessed more thyroid hormone and estrogenic activities than the parent.•The S-enantiomers possessed more potent hormonal activities than R-enantiomers.•Molecular docking revealed the mechanism of stereoselectivity.
Prothioconazole and its metabolite enantiomer exerted stereoselective endocrine-disrupting effects and the metabolic process of prothioconazole generates a toxic metabolite.
Chiral triazole fungicides have played a significant role in plant pathogen control. Although their enantiomers often exhibit different bioactivity, the mechanism of the stereoselectivity has not ...been well studied. The stereoselective bioactivity and mechanisms of prothioconazole and its chiral metabolite against plant pathogenic fungi were investigated. The results indicated that the metabolite exerted more fungicidal activities than the activities of the parent compound. R-Prothioconazole and R-prothioconazole-desthio were 6-262 and 19-954 times more potent against pathogenic fungi than the S-enantiomers, respectively. The R-enantiomers were more effective than in inhibiting the biosynthesis of ergosterol and deoxynivalenol the S-enantiomer. Homology modeling and molecular docking suggested that the R-enantiomers of prothioconazole and prothioconazole-desthio possessed better binding modes than S-enantiomers to CYP51B. Moreover, exposure to prothioconazole and its metabolite enantiomers significantly changed the transcription levels of the CYP51 (CYP 51A, CYP51B, CYP 51C) and Tri (Tri5, Tri6, Tri12) genes. The results showed that application of the R-prothioconazole could require a smaller application amount to eliminate the carcinogenic mycotoxins and any environmental risks.
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•The metabolite possessed better bioactivity than the parent compound.•R-enantiomer is more potent than S-enantiomer against plant pathogenic fungi.•R-enantiomer exerted better binding affinities with CYP51B than S-enantiomer.•R-enantiomer inhibits Tri5 expression more effectively to reduce DON produce.
