Melatonin-priming enhances maize seedling drought tolerance by regulating the antioxidant defense system.

Drought stress (DS) challenges sustainable agriculture production by limiting crop growth and development. The objective of the study was to evaluate the effect of melatonin-priming on enzymatic and non-enzymatic antioxidant defense mechanisms and its relation with leaf ultrastructure and stomatal traits in maize (Zea mays L) seedlings under DS (PEG-6000). DS drastically decreased seed germination, plant growth, and leaf chlorophyll content due to excessive reactive oxygen species (ROS) production. Melatonin-priming significantly (P < 0.05) increased seed germination, root length, shoot length, fresh seedling weight, proline content, total soluble protein content, sugar content, chlorophyll content, and stomatal aperture size by 101%, 30%, 133%, 51%, 22%, 59%, 54%, 20%, and 424%, compared to no priming (NP) under DS, respectively. Similarly, priming improved leaf ultrastructure and reduced the amount of chlorophyll loss and oxidative damage in maize seedlings. Melatonin seed priming with 500 µM melatonin (M2) greatly increased superoxide dismutase (SOD), peroxidase (POD), catalase (CAT), glutathione, and ascorbate (AsA) activity, by 65%, 63%, 94%, 41%, and 55% compared to NP under DS and by 0.26%, 8%, 33%, 42%, and 15% under no-stress (NS), respectively. Melatonin-priming also reduced malondialdehyde content, electrolyte leakage, hydrogen peroxide (H2O2) content, and superoxide anion (O2-) content by 26%, 31%, 31%, and 33% compared to NP under DS and by 8%, 18%, 10%, and 11% under NS, respectively. In response to DS, melatonin-priming also stabilized the chloroplast structure, sustained cell expansion, protected cell walls, and greatly improved stomatal traits, including stomatal number, length, and width. Our results suggest that melatonin-priming improves drought tolerance in maize seedlings by alleviating the negative effect of ROS.

Advancements and greenification potential of magnetic molecularly imprinted polymers for chromatographic analysis of veterinary drug residues in milk.

Milk, as a widely consumed nutrient-rich food, is crucial for bone health, growth, and overall nutrition. The persistent application of veterinary drugs for controlling diseases and heightening milk yield has imparted substantial repercussions on human health and environmental ecosystems. Due to the high demand, fresh consumption, complex composition of milk, and the potential adverse impacts of drug residues, advanced greener analytical methods are necessitated. Among them, functional materials-based analytical methods attract wide concerns. The magnetic molecularly imprinted polymers (MMIPs), as a kind of typical functional material, possess excellent greenification characteristics and potencies, and they are easily integrated into various detection technologies, which have offered green approaches toward analytes such as veterinary drugs in milk. Despite their increasing applications and great potential, MMIPs' use in dairy matrices remains underexplored, especially regarding ecological sustainability. This work reviews recent advances in MMIPs' synthesis and application as efficient sorbents for veterinary drug extraction in milk followed by chromatographic analysis. The uniqueness and effectiveness of MMIPs in real milk samples are evaluated, current limitations are addressed, and greenification opportunities are proposed. MMIPs show promise in revolutionizing green analytical procedures for veterinary drug detection, aligning with the environmental goals of modern food production systems.

Low irrigation water minimizes the nitrate nitrogen losses without compromising the soil fertility, enzymatic activities and maize growth.

Nitrate nitrogen (NO3-_N) leaching increased with nitrogen (N) fertilization under high water supply to the field negatively affected the maize growth and performance. This study aimed to understand the mechanisms of NO3-_N leaching on a biochemical basis and its relationship with plant performance with 5 different doses (0, 200, 250, 300, 350 kg N ha- 1) of N fertilizers under low (60%; LW) and high (80%; HW) water holding capacity. Soil and plant enzymes were observed at different growth stages (V9, R1, R3, and R6) of the maize, whereas the leachates were collected at 10-days intervals from the sowing date. The LW had 10.15% lower NO3-_N leachate than HW, with correspondence increases in grain yield (25.57%), shoot (17.57%) and root (28.67%) dry matter. Irrespective of the irrigation water, RubisCo, glutamine synthase (GS), nitrate reductase (NR), nitrite reductase (NiR), and glutamate synthase (GOGAT) activities increased with increasing N fertilizer up to the V9 growth stage and decreased with approaching the maturity stage (R6) in maize. In HW irrigation, soil total N, GOGAT, soil nitrate (NO3-_N), leached nitrate (LNO3-_N), root N (RN), leaf N (LN) were positively correlated with N factors suggesting the higher losses of N through leaching (11.3%) compared to LW irrigation. However, the malondialdehyde (MDA), hydrogen peroxide (H2O2), superoxide (O2-), and proline were negatively correlated with the other enzymatic activities both under LW and HW irrigation. Thus, minimizing the NO3-_N leaching is possibly correlated with the LW and N300 combination without compromising the yield benefit and improving enzyme activities.

Selective extraction of fungicide carbendazim in fruits using ß-cyclodextrin based molecularly imprinted polymers.

Considering the importance of developing a new analytical approach for pesticide residue detection for the sake of ensuring food safety, a ß-cyclodextrin based molecularly imprinted polymer was prepared for selective determination of carbendazim. The polymers consist of a porous and hollow structure demonstrating the selective abundant adsorption sites for carbendazim molecule. The selectivity and adsorption capacity of the imprinted polymers were analyzed with dispersive solid-phase extraction and analyzed with high performance liquid chromatography coupled with ultraviolet. The results of imprinted polymers were higher than non-imprinted polymers with the maximum adsorption capacity of 3.65 mg/g within 30 min of total adsorption time. The reusability of the imprinted polymers was determined to evaluate its effectiveness and stability, which proved that the polymers lost 10% efficiency within seven consecutive recycles. The developed method displayed good linearity over the concentration range of 0.05-2.0 mg/L. The recovery percentage of 81.33-97.23 with relative standard deviations of 1.49-4.66% was obtained from spiked apple, banana, orange, and peach samples with a limit of detection of 0.03 mg/L and a limit of quantification of 0.10 mg/L (signal to noise ratio = 3/10). The overall performance of the proposed method evident that this technique provided a desirable outcome and it can be used as a convenient approach, as it qualifies the analytical standards.

Etoxazole stereoselective determination, bioaccumulation, and resulting oxidative stress in Danio rerio (zebrafish).

An environmentally-friendly and fast analytical method for the stereoselective determination of etoxazole was developed and then applied to estimate stereoselective bioaccumulation and elimination in zebrafish using SFC-MS/MS. Optimal enantioseparation conditions were determined using a Chiralpak IG-3 column and CO2/MeOH mobile phase (80/20, v/v), at 3.0 mL/min within 1 min, 30°Me and 18 MPa. A modified QuEChERS method was developed for zebrafish sample pretreatment, and mean recoveries were 88.43-110.12% with relative standard deviations ranging from 0.32 to 5.34%. The enantioselectives of etoxazole enantiomers in zebrafish during uptake and depuration phases were evaluated. Significant enantioselective bioaccumulation was observed, with preferential accumulation of (-)-R-etoxazole compared to its antipode, during uptake at both low and high exposure concentrations. The toxic effects of etoxazole on zebrafish were further explored, and activities of antioxidant enzymes were determined in liver of zebrafish. Significant changes were observed in the SOD and GST activities and in the MDA levels, which indicated the occurrence of oxidative stress in liver of zebrafish. The toxic effects exhibited time- and dose-dependent properties. These results can facilitate the accurate risk evaluation of etoxazole and provide basic knowledge for further study of biotoxicity mechanisms.

Synthesis of core-shell magnetic molecularly imprinted polymer for the selective determination of imidacloprid in apple samples.

This work demonstrates the synthesis and characterization of core-shell magnetic molecularly imprinted polymers based on surface imprinting using methacryloyl chloride as a functional monomer for the selective extraction of imidacloprid (template) from apple fruit. The characterization analysis results ensured the successful synthesis of the magnetic molecularly imprinted polymers owing to their heterogeneous structure and good magnetic properties. An isothermal binding test was assessed with a pseudo-second-order kinetic model, and the kinetic results fit well to the Freundlich isothermal model. The polymers exhibited an adsorption capacity of 5.75 mg/g for the target analyte with a good selective extraction ability. In addition, the polymers can be reused several times without significant performance loss. The molecularly imprinted polymers showed good performance in the analysis of spiked apple sample with a linear range of 0.05-1.0 mg/L, a limit of detection of 0.048 mg/L and a limit of quantification of 0.146 mg/L (S/N = 3/10). The recoveries of the samples were 77.66-96.57% and their respective relative standard deviations were 3.36-0.45%. All the results indicated that the proposed method provided good selective extraction, as qualifying the analytical standards.

Geographical origin of Chinese apples based on multiple element analysis.

BACKGROUND: Apples from different regions of China show different qualities and internal characteristics, and appeal to different customers. However, these aspects have not been studied in depth. We characterized the profiles of 14 elements in 317 apple samples collected from five regions of China. Principal component analysis (PCA), linear discriminant analysis (LDA), and back-propagation artificial neural networks analysis (BP-ANN) were used to build models for apple authentication. RESULTS: Fourteen elements were successfully identified in apple samples by performing graphite furnace atomic absorption spectrometry (GFAAS) and inductively coupled plasma atomic emission spectroscopy (ICP-AES) analyses. Comparative analysis showed significantly different element profiles in samples from different regions. The first five principal components obtained by PCA accounted for 71.8% of the total variance. The LDA obtained 70.0% classification rates. The BP-ANN obtained 82.7% classification rates. CONCLUSION: This study indicated the possibility that apples could be authenticated based on differences in their element profiles, and provided a basis for further geographical origin studies. © 2019 Society of Chemical Industry.

Molecularly imprinted polymers' application in pesticide residue detection.

Molecularly imprinted polymers (MIPs) are produced using molecular imprinting technology (MIT) and have specific analyte-binding abilities and unique properties, including chemical and thermal stability, reusability, high selectivity, and high sensitivity. The application of MIPs in the detection of pesticides represents an advance and a superior scientific approach owing to their detection and characterization of trace levels in comparison with other methods. In this review, we have summarized the pre-treatment extraction of pesticides with different types of molecularly imprinted polymer for the detection of single and multiple pesticides by elaborating upon their specific extraction efficiency. The importance of different polymerization methods, functional monomers and cross-linkers is highlighted. The aim of this study is to investigate the importance of the application of MIPs in the detection of pesticides and recent advances in the last few years to overcome the limitations of previously developed methods. Existing restrictions and required future aspects are discussed.

Method development, validation, and risk assessment of multiple pesticide residues of fruits in China.

In this study, a muti-residue analysis method of 40 pesticides in five different categories of fruits in China was developed based on ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS). Five hundred real samples were analyzed and assessed for the dietary exposure risk. The sample treatment method was optimized by comparing four clean-up methods. The matrix effects of different fruits were evaluated. The analytical method was validated in terms of linearity, limit of detection (LOD), limit of quantification (LOQ), accuracy, and precision. The results showed that the optimal method was the treatment by clean up with ODS (octadecylsilane) and MgSO4. The matrix effect was the strongest in orange and weakest in apple. The LOD and LOQ of pesticides were 0.04-5.9 µg kg-1 and 0.13-19.5 µg kg-1, respectively. The recoveries at three spiked levels were ranged from 71.2 to 115.2% with the RSDs from 0.1 to 19.6%. Twenty-two pesticides were detected in 500 fruit samples from the major production regions of China, with concentrations ranging from 0.1 to 1930 µg kg-1. A total of 13, 10, 9, 8, and 4 pesticides were detected in peach, orange, grape, apple, and strawberry. Both the acceptable daily intake (ADI) and acute reference dose (ARfD) for all the detected pesticides were lower than 100%, indicating that the dietary intake risks are acceptable and would not pose potential health risks.

Synthesis of green magnetic molecularly imprinted polymers for selective extraction of rifaximin in milk samples.

In this study, a new analytical method was developed using magnetic molecularly imprinted polymers (MMIPs) by employing eco-friendly supramolecular ternary deep eutectic solvents to synthesize these MMIPs for selective extraction of rifaximin. The characterization analysis and adsorption affinity investigation were conducted. The results showed fast adsorption (15 min) with high adsorption capacity (43.20 mg g-1) and selectivity for rifaximin. Various extraction parameters were optimized, achieving recoveries ranging from 86.67% to 99.47% in spiked milk samples using high-performance liquid chromatography (HPLC). The detection and quantification limits were 0.01 mg L-1 and 0.03 mg L-1, respectively. The method exhibited low RSDs (<4.70%) and excellent selectivity, with MMIPs reusable up to seven times with only a 10% performance loss. This study proposes a convenient and reliable method for trace-level rifaximin extraction from milk using eco-friendly MMIPs.