The widespread presence of triazole fungicides in greenhouse soils in Shandong Province, China: A systematic study on human health and ecological risk assessments.

Triazole fungicides (TFs) are extensively used on greenhouse vegetables and are ubiquitously detected in the environment. However, the human health and ecological risks associated with the presence of TFs in the soil are unclear. In this study, ten widely used TFs were measured in 283 soil samples from vegetable greenhouses across Shandong Province, China, and their potential human health and ecological risks were assessed. Among all soil samples, difenoconazole, myclobutanil, triadimenol, and tebuconazole were the top detected TFs, with detection rates of 85.2-100%; these TFs had higher residues, with average concentrations of 5.47-23.8 µg/kg. Although most of the detectable TFs were present in low amounts, 99.3% of the samples were contaminated with 2-10 TFs. Human health risk assessment based on hazard quotient (HQ) and hazard index (HI) values indicated that TFs posed negligible non-cancer risks for both adults and children (HQ range, 5.33 × 10-10 to 2.38 × 10-5; HI range, 1.95 × 10-9 to 3.05 × 10-5, <1). Ecological risk assessment based on the toxicity exposure ratio (TER) and risk quotient (RQ) values indicated that difenoconazole was a potential risk factor for soil organisms (TERmax = 1 for Eisenia foetida, <5; RQmean = 1.19 and RQmax = 9.04, >1). Moreover, 84 of the 283 sites showed a high risk (RQsite range, 1.09-9.08, >1), and difenoconazole was the primary contributor to the overall risk. Considering their ubiquity and potential hazards, TFs should be continuously assessed and prioritized for pesticide risk management.

Transcriptomic profiling of the cold stress and recovery responsiveness of two contrasting Guizhou HE rice genotypes.

BACKGROUND: At the seed germination stage, rice is sensitive to cold stress, which adversely affects its growth and development. Guizhou HE rice comprises several different landraces, most of which are cold tolerant. OBJECTIVE: To identify differentially expressed genes and molecular mechanism underlying the cold tolerance of Guizhou HE. METHODS: Two Guizhou HE genotypes, AC44 (cold-sensitive) and AC96 (cold-tolerant), which exhibit opposite phenotypes in response to cold treatment at the seed germination stage were used. Comprehensive gene expressions of AC44 and AC96 under 4 °C cold treatment and subsequent recovery conditions were comparatively analyzed by RNA sequencing. RESULTS: Overall, 11,082 and 7749 differentially expressed genes were detected in AC44 and AC96, respectively. Comparative transcriptome analysis demonstrated that, compared with AC44, AC96 presented fewer upregulated and downregulated genes. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analyses demonstrated that AC96 presented more upregulated GO terms, especially terms associated with biological processes. However, AC44 presented more terms related to cellular components, mainly chloroplasts. Moreover, DEGs related to the auxin signaling pathway (including ARF and IAA family members) and transcription factors (including members of the F-box, bZIP, basic helix-loop-helix [bHLH], and MYB-like transcription factor families) were found to be expressed specifically in AC96; thus, these DEGs may be responsible for the cold tolerance of AC96. CONCLUSIONS: These findings present information about the cold tolerance mechanism of Guizhou HE rice at the germination stage, providing valuable resources and candidate genes for breeding cold-tolerant rice genotypes.

Genetic mapping of powdery mildew resistance genes in wheat landrace Guizi 1 via genotyping by sequencing.

BACKGROUND: Wheat (Triticum aestivum L.) powdery mildew (Pm), which caused by Blumeria graminis f. sp. tritici (Bgt), is a destructive disease worldwide that causes severe yield losses in wheat. Resistant wheat cultivars easily lose their ability to effectively resist newly emerged Bgt strains; therefore, identifying new resistance genes is necessary for breeding resistant cultivars. METHODS AND RESULTS: Guizi 1 (GZ1) is a Chinese wheat cultivar with moderate and stable resistance to Pm. Genetic analysis indicated that the Pm resistance of GZ1 was controlled by a single dominant gene, designated PmGZ1. In total, 110 F2 individual plants and their 2 parents were subjected to genotyping by sequencing (GBS), which yielded 23,134 high-quality single-nucleotide polymorphisms (SNPs). The SNP distributions across the 21 chromosomes ranged from 134 on chromosome 6D to 6288 on chromosome 3B. Chromosome 6A has 1866 SNPs, among which 16 are physically located between positions 307,802,221 and 309,885,836 in an approximate 2.3-cM region; this region also had the greatest SNP density. The average map distance between SNP markers was 0.1 cM. A quantitative trait locus (QTL) with a significant epistatic effect on Pm resistance was mapped to chromosome 6A. The logarithm of odds (LOD) value of PmGZ1 was 34.8, and PmGZ1 was located within the confidence interval marked by chr6a-307802221 and chr6a-309885836. Moreover, 74.7% of the phenotypic variance was explained by PmGZ1. Four candidate genes (which encoded two TaAP2-A and two actin proteins) were annotated maybe as resistance genes. CONCLUSIONS: The present results provide valuable information for wheat genetic improvement, QTL fine mapping, and candidate gene validation.

Phase transition and release kinetics of polyphenols encapsulated lyotropic liquid crystals.

In this paper, the lyotropic liquid crystals formed in SL/IP/H2O system were prepared as a drug carrier system to encapsulate polyphenols. The components and introduction of drug had influences in the structure and rheological properties of lyotropic liquid crystals. The structure underwent a phase transition from lamellar phase (Lα) to Lα + HII (reverse hexagonal phase) mixed phases and micelle by increasing its IP/H2O mass ratio from 5/35 to 20/20 and 35/5, consistent with the transition from solid-like properties to viscous fluid properties. For the Lα + HII phase, the loading of DMY induced the structural transition to the HII phase, confirmed by SAXS results. This may be due to the penetration of DMY into the hydrophobic tails of surfactants. The in vitro release kinetic resulted that the release of drug in Lα was associated with diffusional mass transport and matrix swelling. While the release behavior of DMY in HII phase was predominantly controlled by concentration diffusion. These relationships among structure, rheology and release kinetics should be conductive to further design the drug sustained carrier system formed by lyotropic liquid crystals.

A pH-sensitive microemulsion-filled gellan gum hydrogel encapsulated apigenin: Characterization and in vitro release kinetics.

In this work, the incorporation of O/W microemulsion in gellan gum hydrogels was performed to prepare the composite hydrogel as the carrier of apigenin. In vitro release studies resulted that the composite hydrogels could control the drug release under acidic (pH 1.2) and weak alkaline conditions (pH 7.4). This was due to the increase of crosslinking degree under acidic medium and degradation under weak alkaline medium, observed by SEM technique. The FT-IR analysis further confirmed that the hydrogen ions (H+) under acidic conditions could diminish the electrostatic repulsion between the gellan gum molecules by offsetting the negative charge of carboxyl groups, promoting the formation of double helices. The in vitro release kinetics resulted that the release under acidic conditions was a Fickian diffusion-controlled mechanism. While the in vitro release under weak alkaline condition was erosion-controlled mechanism. In addition, the components of microemulsion have also an influence on the release behavior, which was related to the diameter distributions of microemulsion droplets and the hydrogen bond degrees between surfactants and polymers. As a result, the microemulsion-filled hydrogels could be a promising pH-controlled release system for oral delivery of hydrophobic drug.

Temperature/pH-Responsive Hexagonal Liquid Crystal for Curcumin Release.

The temperature/pH-responsive hexagonal liquid crystal constructed in a polyoxyethylene (20) sorbitan monooleate (Tween 80)/water-soluble chitosan (WCS)/ethyl oleate (EtOL)/H2O system was used to encapsulate curcumin. We discuss the effect of temperature and pH on the in vitro release of curcumin and the rheological properties of a curcumin-encapsulated liquid crystal. The drug-encapsulated hexagonal phase containing relatively high WCS content (9.9 wt %) exhibited good temperature response, as indicated by three phase transformation temperature obtained by temperature scanning. The viscosity of the drug-encapsulated hexagonal phase decreased as the temperature rose, which exhibited diverse constancy and temperature sensitivity. Also, the in vitro release rate of curcumin increased as the temperature increased. After introducing WCS, the release rate of curcumin decreased obviously the pH dependence, where the release of curcumin was slower as the pH was higher. All of the results indicated that the temperature/pH-responsive hexagonal liquid crystals were proposed to be potential slow release carriers to deliver curcumin.

Shear rheology and in-vitro release kinetic study of apigenin from lyotropic liquid crystal.

Apigenin is a flavonoid compound with diverse pharmacological functions which could develop health benefit products, but its formulation is hampered by its poor water solubility and bioavailability. In this paper, in order to overcome these difficulties, apigenin was encapsulated in LLC formed by polyoxyethylene-10-oleyl ether (Brij 97) and sodium deoxycholate (NaDC) mixtures. The hexagonal liquid crystalline phase (H) and the cubic liquid crystalline phase (C) were found in this system. The shear rheology was used to study the structure change with temperature. It was shown that C3 (Brij 97-NaDC/IPM-PEG400/H2O=36:9:55) was C at low temperature. But above 35.6°C, the matrix of C3 completely transformed to polymer solution. The matrix of H3 was H (Brij 97-NaDC:IPM-PEG 400:H2O=50:9:41) below 50°C, but the structural strength change was obvious. Vitro release experiment was used to study drug release kinetics. It was indicated that apigenin encapsulated in LLC conformed to the concentration diffusion model, and cumulative percentage of apigenin released from C3 and H3 had corresponding relationship with the shear rheology at different temperatures.

Functional architecture of two exclusively late stage pollen-specific promoters in rice (Oryza sativa L.).

Late stage pollen-specific promoters are important tools in crop molecular breeding. Several such promoters, and their functional motifs, have been well characterized in dicotyledonous plants such as tomato and tobacco. However, knowledge about the functional architecture of such promoters is limited in the monocotyledonous plant rice. Here, pollen-late-stage-promoter 1 (PLP1) and pollen-late-stage-promoter 2 (PLP2) were characterized using a stable transformation system in rice. Histochemical staining showed that the two promoters exclusively drive GUS expression in late-stage pollen grains in rice. 5' deletion analysis revealed that four regions, including the -1159 to -720 and the -352 to -156 regions of PLP1 and the -740 to -557 and the -557 to -339 regions of PLP2, are important in maintaining the activity and specificity of these promoters. Motif mutation analysis indicated that 'AGAAA' and 'CAAT' motifs in the -740 to -557 region of PLP2 act as enhancers in the promoter. Gain of function experiments indicated that the novel TA-rich motif 'TACATAA' and 'TATTCAT' in the core region of the PLP1 and PLP2 promoters is necessary, but not sufficient, for pollen-specific expression in rice. Our results provide evidence that the enhancer motif 'AGAAA' is conserved in the pollen-specific promoters of both monocots and eudicots, but that some functional architecture characteristics are different.

Ternary cubic phases containing ionic liquid.

The phase diagram of 1-butyl-3-methylimidazolium tetrafluoroborate (bmim-BF(4)) in aqueous solutions of oleyl polyoxyethylene (20) ether (C(18:1)E(20)) was determined at 25 degrees C by a combination of visual inspection and small-angle X-ray scattering (SAXS). The micellar cubic Im3m liquid crystalline phase found in the ternary system was investigated by means of SAXS and rheological techniques. The cubic samples show highly elastic gel-like properties indicated by their mechanical and discrete relaxation spectra. Moreover at a constant C(18:1)E(20)/bmim-BF(4) ratio, with decreasing water content the network strength increases. The internal structure apparently becomes more stable, as indicated by an increase in the storage and loss moduli and a decrease in the lattice parameter alpha and interfacial area of per surfactant a(S). Furthermore, investigations on the representative micellar Im3m cubic phases formed in a relatively hydrophobic ionic liquid bmim-PF(6) with C(18:1)E(20) and water ternary system (P(1)), a C(18:1)E(20)/water binary system (J(1)), and C(18:1)E(20)/water/bmim-BF(4) system (B(1)) were made in comparison. It can be clearly seen that appreciably different mechanical spectra and relaxation spectra are shown by the cubic phases investigated. B(1) exhibits a typical gel-like dynamic rheogram while P(1) exhibits fluid-like viscoelastic properties to some extent, and J(1) shows traits of the general Maxwell model. These differences are analyzed through SAXS data as the employment of ionic liquids and their different location in the cubic phases.

Microstructure and rheological properties of liquid crystallines formed in Brij 97/water/IPM system.

The phase diagram of Brij 97/water/IPM systems was determined at 25 degrees C. Rich liquid crystalline phases including Lalpha, H1, and cubic Fd3m phases were identified by means of small angle X-ray scattering (SAXS). Microstructure transitions of liquid crystals with changes in surfactant concentration and oil content are explained qualitatively by the surfactant packing parameter (vL/aSlc). Dynamic rheological results indicate that all three kinds of liquid crystals investigated show high elasticity. The lamellar, Lalpha, phases formed in Brij 97/water with two different oils, oleic acid and geraniol, were also studied in comparison with those of Brij 97/water/IPM systems. The strength of the network of lamellar phases formed in Brij 97/water/oleic acid and Brij 97/water/geraniol systems are appreciably stronger than for Brij 97/water/IPM systems, indicated by the smaller area of surfactant molecules at the interface and the higher moduli (G' and G'').

Molecular interaction in binary surfactant mixtures containing alkyl polyglycoside.

Surface tensions were measured for several binary mixtures of a multidegree polymerized alkyl polyglycoside, C12G1.46' with different types of surfactants in 0.1 M NaCl at 25 degrees C. Based on regular solution theory, using a dimensional crystal model and a phase separation model, the molecule exchange energy in mixed monolayer formation (epsilon) and mixed micellization (epsilon(m)) were determined. Surfactants used in the mixtures with C12G1.46 in this study are C12E3S (trioxyethylenated dodecyl sulfonate), C12TAC (dodecyl trimethylammonium chloride), BE-6 (hexaoxyethylenated trisiloxane surfactant), and TMN-6 (hexaoxyethylenated-2,6,8-trimethylnonanol). The mixtures show exchange energy in mixed monolayer formation (epsilon) and mixed micellization (epsilon(m)) ranging from -660 to -1410 J/mol, indicating a decrease in surface energy upon mixing. The decreases in surface energy are in the order C12G1.46/C12E3S > C12G1.46/C12TAC, C12G1.46/C12TAC > C12G2/C12TAC and C12G1.46/BE-6 > C12G1.46/TMN-6. The ability of the mixed monolayer formation relative to the mixed micelle formation of the same binary mixture, measured by the (epsilon-epsilon(m)) values, is in the order C12G1.46/BE-6 > C12G1.46/TMN-6 > C12G1.46/C12E3S-->0 > C12G1.46/C12TAC.

Hexagonal liquid crystalline phases formed in ternary systems of Brij 97-water-ionic liquids.

Phase diagrams of two ionic liquids: hydrophobic 1-butyl-3-methylimidazolium hexafluorophosphate (bmim-PF(6)) and relatively hydrophilic 1-butyl-3-methylimidazolium tetrafluoroborate (bmim-BF(4)) in aqueous solutions of Brij 97 were determined at 25 degrees C. Two hexagonal liquid crystalline phases formed in bmim-PF(6)- and bmim-BF(4)-containing ternary systems were investigated by means of small-angle X-ray scattering (SAXS) and rheological techniques, with comparison of composition and temperature effects. From analysis of the SAXS data, bmim-PF(6) is dominantly penetrated between the oxyethylene chains of surfactant molecules, whereas bmim-BF(4) is mainly located in the water layer of hexagonal phases. The strength of the network of hexagonal phase formed in the Brij 97/water/bmim-BF(4) system is appreciably stronger than that of the Brij 97/water/bmim-PF(6) system, indicated by the smaller area of the surfactant molecule at the interface and the higher moduli (G', G' '). Temperature has a converse effect on the lattice parameters of the two hexagonal phases.