Nano-based smart formulations: A potential solution to the hazardous effects of pesticide on the environment

Enhancing Environment Resistance and Bioactivity of Pesticide Enabled by Structure-Controllable Polymer Nanocarriers: Emphasizing the Role of Morphology

Nano-formulated pesticides are increasingly desired to control the insect pest and plant disease with superior efficacy for guaranteeing the high yield and quality in crop production. However, the impact of nanocarrier morphology on pesticide resistance against rainwash, photolysis, and overall pesticide bioactivity remains unknown. In this work, a series of well-defined and morphology-controllable polymer nanocarriers for pesticide are fabricated through polymerization-induced self-assembly. All these generated soft nanocarriers with hydrophobic regions exhibit excellent pesticide loading capacity over 70%. After foliar spraying, the generated one-dimensional worm-like nanopesticides exhibit an extremely high retention of 80% on leaves after 10 mm rainfall (only 10% for naked pesticide) and a good resistance to photodegradation under UV irradiation (less than 50% for worm-like micelle vs 70% for naked pesticide degradation after 20 h irradiation under 365 nm). Therefore, worm-like nanocarriers show higher bioactivity than that of spherical nanocarriers. In general, the comprehensive performance order of pesticide-loaded polymer nanocarriers is worm-like micelle > spherical vesicle > spherical micelle. Moreover, the facilely resultant soft nanocarriers of pesticides possess a remarkable low cytotoxicity and excellent biocompatibility in human cells. This nanoplatform possesses simple fabrication, structure controllability, excellent performances, and environmental friendliness, enabling the nanocarriers promising for effective pesticide delivery.

Unraveling the secrets: Evolution of resistance mediated by membrane proteins

Membrane protein-mediated resistance is a multidisciplinary challenge that spans fields such as medicine, agriculture, and environmental science. Understanding its complexity and devising innovative strategies are crucial for treating diseases like cancer and managing resistant pests in agriculture. This paper explores the dual nature of resistance mechanisms across different organisms: On one hand, animals, bacteria, fungi, plants, and insects exhibit convergent evolution, leading to the development of similar resistance mechanisms. On the other hand, influenced by diverse environmental pressures and structural differences among organisms, they also demonstrate divergent resistance characteristics. Membrane protein-mediated resistance mechanisms are prevalent across animals, bacteria, fungi, plants, and insects, reflecting their shared survival strategies evolved through convergent evolution to address similar survival challenges. However, variations in ecological environments and biological characteristics result in differing responses to resistance. Therefore, examining these differences not only enhances our understanding of adaptive resistance mechanisms but also provides crucial theoretical support and insights for addressing drug resistance and advancing pharmaceutical development.

Steerable Interfacial Assembly of 1D Amyloid-Like Protein Nanocomposites for Enhanced Nanoherbicide Utilization

Conventional herbicide formulations suffer from serious problems such as easy drift, run-off and scouring into the environment, which pose enormous threats to human health and environmental safety. Herein, an innovative strategy is proposed to prepare oil-in-water nanoemulsions with long-term stability, enhanced droplet deposition, and improved nanoherbicide adhesion via steerable interfacial assembly of 1D amyloid-like protein nanocomposites. Bovine serum albumin (BSA) undergoes rapid amyloid-like aggregation upon reduction of its disulfide bond. The resulting phase-transitioned BSA (PTB) oligomers instantly self-assemble on the surface of cellulose nanofibers (CNF) to form the 1D PTB/CNF nanocomposites, which greatly expands the parameter space for interfacial assembly of amyloid-like proteins. The PTB/CNF nanocomposites exhibit excellent interfacial activity, enabling spontaneous adsorption at the oil-water interface to stabilize nanoemulsion. The excess PTB/CNF nanocomposites would also self-assemble at the air-aqueous interface upon spraying, resulting in efficient droplet deposition on (super)hydrophobic leaves. The deposited nanoherbicides show excellent resistance to wind/rain corrosion due to the robust amyloid-mediated adhesion, with a retention rate of more than 80% after severe scouring. Consequently, herbicide applications can be reduced by at least 30% compared to commercial emulsifiable concentrates, showing greater herbicidal efficiency. This study provides novel insights and approaches to promote sustainable agricultural development.

Upconversion fluorescence nanosensor based on enzymatic inhibited and copper-triggered o-phenylenediamine oxidation for the detection of dimethoate pesticides

Pesticide residues in agricultural products pose a significant threat to human health. Herein, a sensitive fluorescence method employing upconversion nanoparticles was developed for detecting organophosphorus pesticides (OPs) based on the principle of enzyme inhibition and copper-triggered o-phenylenediamine (OPD) oxidation. Copper ions (Cu2+) oxidized the colorless OPD to a yellow 2,3-diaminophenazine (oxOPD). The yellow solution oxOPD quenched the fluorescence of upconversion nanoparticles due to the fluorescence resonance energy transfer. The high affinity of Cu2+ for thiocholine reduced the level of oxOPD, resulting in almost no fluorescence quenching. The addition of dimethoate led to the inhibition of acetylcholinesterase activity and thus prevented the formation of thiocholine. Subsequently, Cu2+ oxidized OPD to form oxOPD, which attenuated the fluorescence signal of the system. The detection system has a good linear range of 0.01 ng/mL to 50 ng/mL with a detection limit of 0.008 ng/mL, providing promising applications for rapid detection of dimethoate.

Engineering Entomopathogenic Fungi Using Thermal-Responsive Polymer to Boost Their Resilience against Abiotic Stresses

Entomopathogenic fungi offer an ecologically sustainable and highly effective alternative to chemical pesticides for managing plant pests. However, the efficacy of mycoinsecticides in pest control suffers from environmental abiotic stresses, such as solar UV radiation and temperature fluctuations, which seriously hinder their practical application in the field. Herein, we discovered that the synthetic amphiphilic thermal-responsive polymers are able to significantly enhance the resistance of Metarhizium robertsii conidia against thermal and UV irradiation stresses. The thermosensitive polymers with extremely low cytotoxicity and good biocompatibility can be engineered onto the M. robertsii conidia surface by anchoring hydrophobic alkyl chains. Further investigations revealed that polymer supplementation remarkably augmented the capacity for penetration and the virulence of M. robertsii under heat and UV stresses. Notably, broad-spectrum entomopathogenic fungi can be protected by the polymers. The molecular mechanism was elucidated through exploring RNA sequencing and in vivo/vitro enzyme activity assays. This work provides a novel avenue for fortifying the resilience of entomopathogenic fungi, potentially advancing their practical application as biopesticides.

A flexible modulated pesticide release platform through poly(urethane-urea) microcapsules: effect of different crosslinkers compositions

BACKGROUND

Polymeric microcapsules (MCs) have become an important issue and have attracted increasing attention because of their tunable physical and chemical properties. Diverse shell structures can confer multiple properties on MCs.

RESULTS

Different polyols (1,4-butanediol and glycerin) and polyamines (triethylenetetramine and isophorondiamine) were selected as crosslinkers to obtain emamectin benzoate (EB)-loaded poly(urethane-urea) MCs (PU-MCs) by interfacial polymerization. The four obtained PU-MCs showed sphericity with different degrees of smoothness on their surfaces, and displayed a uniform size distribution ranging from 500 to 700 nm. Moreover, transmission electron microscopy showed that the shell thickness was roughly uniform, and was greatly influenced by the type and structure of the crosslinker. GI-MCs, prepared using glycerin and isophorondiamine, had the largest shell thickness. GT-MCs, obtained using glycerin and triethylenetetramine, had the highest encapsulation efficiency and drug-loading content, and BT-MCs, obtained using mixtures of 1,4-butanediol and triethylenetetramine, had the fastest release behavior. Thermogravimetric analysis revealed that the greater the degree of shell crosslinking, the higher decomposition temperature and the greater the thermal stability. A BT-MC suspension had the lowest viscosity and contact angle with the best wettability. Bioassay experiments showed that BT-MCs exhibited good insecticidal activity against Plutella xylostella larvae with a half-maximal lethal concentration of 4.19 mg/L. Furthermore, a BT-MC suspension showed good thermal and light stability, with potential applications in minimizing the toxicity of EB through sustained release.

CONCLUSION

Various properties of EB-loaded PU-MCs were modulated through simple selection of different polyols and polyamines during fabrication, which might have an important role in constructing the pesticide delivery system and improving pesticide utilization. © 2024 Society of Chemical Industry.

Green synthesized lignin nanoparticles for the sustainable delivery of pyraclostrobin to control strawberry diseases caused by Botrytis cinerea

Lignin, renowned for its renewable, biocompatible, and environmentally benign characteristics, holds immense potential as a sustainable feedstock for agrochemical formulations. In this study, raw dealkaline lignin (DAL) underwent a purification process involving two sequential solvent extractions. Subsequently, an enzyme-responsive nanodelivery system (Pyr@DAL-NPs), was fabricated through the solvent self-assembly method, with pyraclostrobin (Pyr) loaded into lignin nanoparticles. The Pyr@DAL-NPs shown an average particle size of 250.4 nm, demonstrating a remarkable loading capacity of up to 54.70 % and an encapsulation efficiency of 86.15 %. Notably, in the presence of cellulase and pectinase at a concentration of 2 mg/mL, the release of Pyr from the Pyr@DAL-NPs reached 92.66 % within 120 h. Furthermore, the photostability of Pyr@DAL-NPs was significantly improved, revealing a 2.92-fold enhancement compared to the commercially available fungicide suspension (Pyr SC). Bioassay results exhibited that the Pyr@DAL-NPs revealed superior fungicidal activity against Botrytis cinerea over Pyr SC, with an EC50 value of 0.951 mg/L. Additionally, biosafety assessments indicated that the Pyr@DAL-NPs effectively declined the acute toxicity of Pyr towards zebrafish and posed no negative effects on the healthy growth of strawberry plants. In conclusion, this study presents a viable and promising strategy for developing environmentally friendly controlled-release systems for pesticides, offering the unique properties of lignin.

Nano-Selenium and Glutathione Enhance Cucumber Resistance to Botrytis cinerea by Promoting Jasmonic Acid-Mediated Cucurbitacin Biosynthesis

Nano-selenium (Nano-Se), as a biological stimulant, promotes plant growth and development, as well as defense against biotic and abiotic stresses. Glutathione (GSH) is a crucial antioxidant and is also involved in the plant defense response to various stresses. In this study, the efficacy of combined treatment of Nano-Se and GSH (SeG) on the resistance of cucumber plants to Botrytis cinerea was investigated in terms of the plant phenotype, gene expression, and levels of accumulated metabolites using transcriptomic and metabolomic analyses. The exogenous application of SeG significantly enhanced plant growth and increased photosynthetic pigment contents and capacity. Notably, B. cinerea infection was reduced markedly by 41.9% after SeG treatment. At the molecular level, the SeG treatment activated the alpha-linolenic acid metabolic pathway and upregulated the expression of genes responsible for jasmonic acid (JA) synthesis, including LOX (210%), LOX4 (430%), AOS1 (100%), and AOC2 (120%), therefore promoting JA accumulation in cucumber. Intriguingly, the level of cucurbitacin, an important phytoalexin in cucurbitaceous plants, was found to be increased in SeG-treated cucumber plants, as was the expression of cucurbitacin biosynthesis-related genes OSC (107.5%), P450 (440.8%,31.6%), and ACT (414.0%). These genes were also upregulated by JA treatment, suggesting that JA may be an upstream regulator of cucurbitacin biosynthesis. Taken together, this study demonstrated that pretreatment of cucumber plants with SeG could activate the JA signaling pathway and promote cucurbitacin biosynthesis to enhance the resistance of the plants to B. cinerea infection. The findings also indicate that SeG is a promising biostimulant for protecting cucumber plants from B. cinerea infection without growth loss.

Design, Synthesis, Bioactivity, and Tentative Exploration of Action Mode for Benzyl Ester-Containing Derivatives

The active splicing strategy has witnessed improvement in bioactivity and antifungal spectra in pesticide discovery. Herein, a series of simple-structured molecules (Y1-Y53) containing chloro-substituted benzyl esters were designed using the above strategy. The structure-activity relationship (SAR) analysis demonstrated that the fatty acid fragment-structured esters were more effective than those containing an aromatic acid moiety or naphthenic acid part. Compounds Y36 and Y41, which featured a thiazole-4-acid moiety and trifluoromethyl aliphatic acid part, respectively, exhibited excellent in vivo curative activity (89.4%, 100 mg/L Y36) and in vitro fungicidal activity (EC50 = 0.708 mg/L, Y41) against Botrytis cinerea. Determination of antifungal spectra and analysis of scanning electron microscopy (SEM), membrane permeability, cell peroxidation, ergosterol content, oxalic acid pathways, and enzymatic assays were performed separately here. Compound Y41 is cost effective due to its simple structure and shows promise as a disease control candidate. In addition, Y41 might act on a novel target through a new pathway that disrupts the cell membrane integrity by inducing cell peroxidation.

Bacillus megaterium: Evaluation of Chemical Nature of Metabolites and Their Antioxidant and Agronomics Properties

Bacillus megaterium is particularly known for its abundance in soils and its plant growth promotion. To characterize the metabolites excreted by this specie, we performed successive liquid/liquid extractions from bacteria culture medium with different polarity solvents (cyclohexane, dichloromethane, ethyl acetate and butanol) to separate the metabolites in different polarity groups. The extracts were characterized regarding their total phenolic content, the amount of reducing sugar, the concentration of primary amines and proteins, their chromatographic profile by HPLC-DAD-ELSD and their chemical identification by GC-MS. Among the 75 compounds which are produced by the bacteria, 19 identifications were for the first time found as metabolites of B. megaterium and 23 were described for the first time as metabolites in Bacillus genus. The different extracts containing B. megaterium metabolites showed interesting agronomic activity, with a global inhibition of seed germination rates of soya, sunflower, corn and ray grass, but not of corn, compared to culture medium alone. Our results suggest that B. megaterium can produce various metabolites, like butanediol, cyclic dipeptides, fatty acids, and hydrocarbons, with diverse effects and sometimes with opposite effects in order to modulate its response to plant growth and adapt to various environmental effects. These findings provide new insight into bioactive properties of this species for therapeutic uses on plants.

Occurrence, distribution and ecological risk assessment of herbicide residues in cropland soils from the Mollisols region of Northeast China

The first systematic and comprehensive investigation of herbicide residues was conducted by identifying their spatial distribution, influencing factors and ecological risk in cropland soils from the Mollisols region covering 109 million hm2 in Northeast China. Fifty-six herbicides were detected with total herbicide concentrations ranging from 1.01 to 1558.13 μg/kg (mean: 227.45). Atrazine, its degradates deethyl atrazine (DEA) and deisopropyl atrazine (DIA), trifluralin and butachlor were the most frequently detected herbicides, while DEA, clomazone, nicosulfuron, fomesafen, and mefenacet exhibited the highest concentrations. Despite being less frequently reported in Chinese soils, fomesafen, nicosulfuron, clomazone, and mefenacet were found widely present. Although most of the compounds posed a minimal or low ecological risk, atrazine, nicosulfuron and DEA exhibited medium to high potential risks. The key factors identified to regulate the fate of herbicides were soil chemical properties, amount of herbicides application, and the crop type. The soybean soils showed highest herbicide residues, while the soil mineral contents likely adsorbed more herbicides. This study provides a valuable large-scale dataset of herbicide residues across the entire Mollisols region of China along with fine-scale characterization of the ecological risks. Mitigation and management measures are needed to reduce the herbicide inputs and residues in the region.

Toxicity and Behavior-Altering Effects of Three Nanomaterials on Red Imported Fire Ants and Their Effectiveness in Combination with Indoxacarb

The red imported fire ant (Solenopsis invicta Buren) is one of the 100 worst invasive alien species in the world. At present, the control of red imported fire ants is still mainly based on chemical control, and the most commonly used is indoxacarb bait. In this study, the contact and feeding toxicity of 16 kinds of nanomaterials to workers, larvae, and reproductive ants were evaluated after 24 h, 48 h, and 72 h. The results showed that the mortality of diatomite, Silica (raspberry-shaped), and multi-walled carbon nanotubes among workers reached 98.67%, 97.33%, and 68%, respectively, after contact treatment of 72 h. The mortality of both larval and reproductive ants was less than 20% after 72 h of treatment. All mortality rates in the fed treatment group were below 20% after 72 h. Subsequently, we evaluated the digging, corpse-removal, and foraging behaviors of workers after feeding with diatomite, Silica (raspberry-shaped), and multi-walled carbon nanotubes for 24 h, which yielded inhibitory effects on the behavior of red imported fire ants. The most effective was diatomite, which dramatically decreased the number of workers that dug, extended the time needed for worker ant corpse removal and foraging activities, decreased the number of workers that foraged, and decreased the weight of the food carried by the workers. In addition, we also evaluated the contact and feeding toxicity of these three nanomaterials in combination with indoxacarb on red imported fire ants. According to contact toxicity, after 12 h of contact treatment, the death rate among the red imported fire ants exposed to the three materials combined with indoxacarb reached more than 97%. After 72 h of exposure treatment, the mortality rate of larvae was more than 73% when the nanomaterial content was above 1% and 83% when the diatomite content was 0.5%, which was significantly higher than the 50% recorded in the indoxacarb control group. After 72 h of feeding treatment, the mortality of diatomite, Silica (raspberry-shaped), and multi-walled carbon nanotubes combined with indoxacarb reached 92%, 87%, and 98%, respectively. The death rates of the three kinds of composite ants reached 97%, 67%, and 87%, respectively. The three kinds of composite food had significant inhibitory effects on the behavior of workers, and the trend was largely consistent with the effect of nanomaterials alone. This study provides technical support for the application of nanomaterials in red imported fire ant control.

Preparation and Comprehensive Evaluation of the Efficacy and Safety of Chlorantraniliprole Nanosuspension

Chlorantraniliprole is a broad-spectrum insecticide that has been widely used to control pests in rice fields. Limited by its low solubility in both water and organic solvents, the development of highly efficient and environmentally friendly chlorantraniliprole formulations remains challenging. In this study, a low-cost and scalable wet media milling technique was successfully employed to prepare a chlorantraniliprole nanosuspension. The average particle size of the extremely stable nanosuspension was 56 nm. Compared to a commercial suspension concentrate (SC), the nanosuspension exhibited superior dispersibility, as well as superior foliar wetting and retention performances, which further enhanced its bioavailability against Cnaphalocrocis medinalis. The nanosuspension dosage could be reduced by about 40% while maintaining a comparable efficacy to that of the SC. In addition, the chlorantraniliprole nanosuspension showed lower residual properties, a lower toxicity to non-target zebrafish, and a smaller effect on rice quality, which is conducive to improving food safety and the ecological safety of pesticide formulations. In this work, a novel pesticide-reduction strategy is proposed, and theoretical and data-based support is provided for the efficient and safe application of nanopesticides.