Metabolomics analysis of the effects of chelerythrine on Ustilaginoidea virens.

Rice false smut (RFS) caused by Ustilaginoidea virens is widely distributed in major rice-producing regions. Previous studies have shown that treating RFS with chelerythrine can decrease the germination of fungus spores by 86.7% and induce fungal cell apoptosis. In the present study, the effects of chelerythrine on the metabolism of U. virens explored using metabolomics and analyses of differentially accumulated metabolites and altered metabolic pathways. The top 15 metabolites in random forest analysis were significantly different between groups. In positive ion mode, purine, phenylalanine metabolism, phenylalanine, tyrosine, tryptophan biosynthesis, pyrimidine metabolism, and nitrogen metabolism were dominant. Alanine, aspartate, glutamate metabolism, and phenylalanine metabolism were enriched in negative ion mode. Differentially expressed genes and altered metabolic pathways of U. virens were effected by chelerythrine. The findings support future research on the prevention and treatment of RFS by chelerythrine and provide a theoretical basis for targeted drug delivery.

Fe doped amorphous single layered vanadyl phosphate nanosheets as highly efficient electrocatalyst for water oxidation.

The search for earth-abundant water oxidation electrocatalysts with low-cost and high-performance is essential to the energy conversion field. Well defined, rational designed two-dimensional materials have attracted enormous interest in light of much more specific surface areas and unique electronic properties. Herein, we report a facile two-phase solvothermal approach for the synthesis of Fe doped amorphous single-layered (~0.85 nm) vanadyl phosphate nanosheets (Fe-Am VOPO4). The obtained electrocatalyst exhibits excellent OER electrocatalytic performance, only require overpotential of 215 mV and 270 mV to reach current densities of 10 and 100 mA cm-2 in 1.0 M KOH electrolyte, and long-term electrochemical stability of 40 h. This work strikes out a path of synthesis of graphene-like materials with amorphous phase, and explores a new type of phosphate for efficient OER electrocatalysts.

In vitro antifungal activity and possible mechanisms of action of chelerythrine.

Chelerythrine (CHE) possesses broad pharmacological activities. In this study, the extract of Chelidonium majus L. were characterized by high performance liquid chromatography (HPLC), infrared radiation (IR) spectroscopy and nuclear magnetic resonance (NMR). It was proved that the extract was CHE. The antifungal activity of CHE against five fungal pathogens of rice was researched in vitro, revealing that CHE inhibited Ustilaginoidea virens (U. virens) and Cochliobolus miyabeanus (C. miyabeanus) with 50% effective concentrations (EC50) of 6.53 × 10-3 mg/mL and 5.62 × 10-3 mg/mL, respectively. When the concentration of CHE was 7.5 × 10-3 mg/mL, the inhibition rate of U. virens reached 56.1%. Moreover, CHE (4 × 10-3 mg/mL) exhibited the greatest efficacy in inhibiting spore of U. virens growth with an inhibition rate as high as 86.7%. CHE displayed the best inhibitory activity against U. virens at the concentration of 7.5 × 10-3 mg/mL, compared with the other two isoquinoline alkaloids and commercial fungicide validamycin. After treating U. virens mycelia with CHE, twisted and atrophied mycelia were observed by optical microscopy. SEM results demonstrated narrow and locally fractured mycelium. TEM observations showed that the cell wall had become thin and broken, and most organelles were difficult to recognize. Furthermore, membrane of mycelia was destroyed and reactive oxygen species (ROS) of spores was accumulated, which induced apoptosis of pathogenic fungi. From these results, our understanding of the mechanisms of antifungal activity of CHE against U. virens was enriched and this research is relevant for developing novel pesticides.

High through-put determination of 28 veterinary antibiotic residues in swine wastewater by one-step dispersive solid phase extraction sample cleanup coupled with ultra-performance liquid chromatography-tandem mass spectrometry.

We developed a QuEChERS (quick, easy, cheap, effective, rugged and safe) method for the high through-put determination of 28 common veterinary antibiotics in swine wastewater using one-step dispersive solid-phase extraction (d-SPE) for sample cleanup and ultra-performance liquid chromatography-tandem mass spectrometry for detection. The orthogonal test method was used to systematically investigate the parameters that might influence d-SPE efficiency. The optimal d-SPE procedure utilized 40 mg primary secondary amine sorbent and 3 g L-1 Na2EDTA. The recoveries ranged from 50 to 100% with relative standard deviations <20% for all target analytes except for enrofloxacin and chlortetracycline. The limits of detection and limits of quantification for all the analytes ranged from 0.002 to 0.200 ng mL-1 and 0.005-0.500 ng mL-1, respectively. The developed method was successfully applied to the analysis of 28 antibiotic residues in swine wastewater from 10 pig farms located in central China. Fourteen antibiotics including 4 sulfonamides (sulfadiazine, sulfamerazine, sulfamonomethoxine and trimethoprim), 5 fluoroquinolones (norfloxacin, ciprofloxacin, pefloxacin, enrofloxacin, and ofloxacin), 1 lincosamide (lincomycin) and 4 tetracyclines (doxycycline, tetracycline, oxytetracycline, and chlortetracycline) were detected at levels ranging from 0.0560 to 1793 ng mL-1. Our results demonstrated that the optimized method is a simple but reliable analytical technique for the routine monitoring of veterinary antibiotics in swine wastewater. Swine wastewater samples that we analyzed from 10 pig farms in Jiangxi Province, China were highly contaminated and pose a serious threat to ecosystems and to public health.

Extraction of Chelerythrine and its Effects on Pathogenic Fungus Spore Germination.

BACKGROUND: Chemical fungicides are widely used to control crop diseases, but these chemicals have adverse effects. They destroy the ecological environment and even have toxic effects on human beings. In this context, the development of botanical pesticides is relevant. One potential botanical pesticide is chelerythrine, a main alkaloid of Chelidonium majus L., which has high antitumor, fungistasis, and antiphlogosis bioactivity. OBJECTIVE: This study was designed to present an ultrasonic extraction method for chelerythrine and spore germination experiments to inhibit pathogenic fungi. Fungistasis of chelerythrine is now centralized in basic microbiology experiments, such as observing bacteriostatic rings. This study investigates chelerythrine based on pathogenic fungal spore germination and the influence of germ tube elongation. MATERIALS AND METHODS: Samples of C. majus L., which were wild used in this experiment, were picked from Harbin experimental forest farm of Northeast Forestry University. An L9 (34) orthogonal experiment was designed to optimize the ultrasonic extraction method. All the plant pathogenic fungus strains used in the experiment were preservation strains of Northeast Forestry University Microbial preservation center. Pathogenic fungi were cultivated by joining chelerythrine with and observed germ tube growth and spore germination. RESULTS: The optimum ultrasonication extraction process for chelerythrine has a liquid/solid ratio of 1:8, 35 min of extraction time, 85% of ultrasonic frequency, and 75% of ethanol concentration. When the concentration of chelerythrine was 1.7 × 10-2 mg/ml, the inhibition rates of Septoria microspora Speg. spores and Curvularia lunata were 96.67% and 84.94%, respectively. Moreover, when the concentration of chelerythrine was 1.7 × 10-6 mg/ml, the inhibition rates of S. microspora spores and C. lunata were 47.64% and 12.05%, respectively. CONCLUSION: Fungistasis activity reached a high level with 1.7 × 10-6 mg/ml of chelerythrine. Chelerythrine has the characteristics of less dosage and obvious fungistasis and has a good prospect for botanical fungicide development. SUMMARY: S. microspora spores in chelerythrine concentration of 1.7 × 10-6 mg/ml have an inhibition rate of 47.64%. For chelerythrine concentrations 1.7 × 10-5, 1.7 × 10-4, and 1.7 × 10-3 mg/ml, the inhibition rate is 70%, 80%, and 90%, respectively. When the concentration of chelerythrine was original 1.7 × 10-2 mg/ml, the inhibition rate was 96.67%. As shown in the diagram, the germinal tubes of S. microspora spores were shorter than 50 µm with 1.7 × 10-6, 1.7 × 10-5, and 1.7 × 10-4 mg/ml concentrations of chelerythrine. However, the germinal tubes of spores without chelerythrine could reach 80 µm. With 1.7 × 10-3 mg/ml liquid concentration, the germination was severely inhibited; the germination under concentrate chelerythrine was limited. The inhibitory effect of chelerythrine was greatest in S. microspora. Abbreviations used:C. majus L.: Chelidonium majus L.; Sphaerulina juglandis: S. juglandis; Septoria microspora Speg.: S. microspora; Fusarium oxysporum f. sp. Lycopersici: F. oxysporum f. sp. lycopersici; F. oxysporum f. cucumerinum: F. oxysporum f. cucumerinum; Curvularia lunata: C. lunata.