Search

Type 2 diabetes has been linked to cognitive impairment, but its potential metabolic mechanism is still unclear. The present study aimed to explore neuron-astrocyte metabolic cooperation in the brain of diabetic (db/db, BKS.Cg-m+/+ Leprdb/J) mice with cognitive decline using 13C NMR technique in combination with intravenous [2-13C]-acetate and [3-13C]-lactate infusions. We found that the 13C-enrichment from [2-13C]-acetate into tricarboxylic acid cycle intermediate, succinate, was significantly decreased in db/db mice with cognitive decline compared with wild-type (WT, C57BLKS/J) mice, while an opposite result was obtained after [3-13C]-lactate infusion. Relative to WT mice, db/db mice with cognitive decline had significantly lower 13C labeling percentages in neurotransmitters including glutamine, glutamate, and g-aminobutyric acid after [2-13C]-acetate infusion. However, [3-13C]-lactate resulted in increased 13C-enrichments in neurotransmitters in db/db mice with cognitive decline. This may indicate that the disturbance of neurotransmitter metabolism occurred during the development of cognitive decline. In addition, a reduction in 13C-labeling of lactate and an increase in gluconeogenesis were found from both labeled infusions in db/db mice with cognitive decline. Therefore, our results suggest that the development of cognitive decline in type 2 diabetes may be implicated to an unbalanced metabolism in neuron-astrocyte cooperation and an enhancement of gluconeogenesis. [ABSTRACT FROM AUTHOR]

Background: Diabetes-associated cognition decline is one of central nervous system complications in diabetic mellitus, while its pathogenic mechanism remains unclear. In this study, 1H nuclear magnetic resonance-based metabonomics and immunohistochemistry was used to explore key metabolic alterations in hippocampus of type 2 diabetic db/db mice with cognition decline in order to advance understanding of mechanisms underlying the pathogenesis of the disease. Results: Metabonomics reveals that lactate level was significantly increased in hippocampus of db/db mice with cognition decline compared with age-matched wild-type mice. Several tricarboxylic acid cycle intermediates including succinate and citrate were reduced in hippocampus of db/db mice with cognition decline. Moreover, an increase in glutamine level and a decrease in glutamate and γ-aminobutyric acid levels were observed in db/db mice. Results from immunohistochemistry analysis show that glutamine synthetase was increased and glutaminase and glutamate decarboxylase were decreased in db/db mice. Conclusions: Our results suggest that the development of diabetes-associated cognition decline in db/db mice is most likely implicated in a reduction in energy metabolism and a disturbance of glutamate-glutamine shuttling between neurons and astrocytes in hippocampus. [ABSTRACT FROM AUTHOR]

Aflatoxin B1 (AFB1) is one of the toxic secondary metabolites of fungi belonging to the genus Aspergillus. AFB1 causes hepatotoxicity and carcinogenicity. Mostly, cereals, nuts, fruits, and stored commodities are prone to their attack. It has great health and economic importance. Under suitable conditions, fungus shows maximum pathogenicity which leads to the abundant production of AFB1. This study encompasses the selection of the most pathogenic strain producing abundant AFB1. For this purpose, 50 isolates were tested and YF18 was the most pathogenic. This isolate was then evaluated on 15 culture media which concluded that Yeast Extract Sucrose (YES) agar and Yeast Peptone Dextrose (YPD) agar media proved best for the optimal growth of A. flavus and abundant yield of AFB1. Moreover, the culture media showing optimal growth under different levels of growth conditions i.e., temperature, pH, and water activity, and their effect was verified with the aid of correlation and response surface methodology. The culture media were checked at five levels of temperature (15°C, 20°C, 25°C, 30°C, and 35°C), pH (3.5, 4.0, 4.5, 5.0 and 5.5), and water activity (0.80, 0.85, 0.90, 0.95, and 0.995) were tested, confirming that temperature of 30oC, pH of 5.5 and water activity level of 0.995 significantly enhanced the growth of A. flavus and production of AFB1 (P<0.05); while correlation, as well as response surface methodology, also concluded the level of conditions appropriate for mycelial growth and AFB1 yield. Afterward, the isolate YF18 was applied to the grapes and biochemical parameters were evaluated. The biochemical analysis concluded that fungal infected grapes showed less acidity, TSS, total sugars, TPC, and DPPH as compared to non-treated grapes while the berry size and berry weight was also reduced in infected grapes. The isolate was subjected to 16S rDNA analysis for identification which revealed that fungus is A. flavus and the aflR gene was responsible for activation and release of aflatoxin B1. The present study will help to devise management strategies to reduce the incidence of fungus and its respective toxin. [ABSTRACT FROM AUTHOR]

In 2018, we conducted a cross-sectional study to investigate azole resistance in environmental Aspergillus fumigatus isolates obtained from different agricultural fields in China. Using 63 soil cores, we cultured for azole-resistant A. fumigatus and characterized isolates by their cyp51A gene type, short tandem repeat genotype, and mating type. Of 206 A. fumigatus isolates, 21 (10.2%) were azole resistant. Nineteen of 21 had mutations in their cyp51A gene (5 TR34/L98H, 8 TR34/L98H/S297T/F495I, 6 TR46/Y121F/T289A). Eighteen were cultured from soil samples acquired from strawberry fields, suggesting this soil type is a potential hotspot for azole resistance selection. Twenty resistant isolates were mating type MAT1-1, suggesting asexual sporulation contributed to their evolution. Prochloraz, difenoconazole, and tebuconazole were the most frequently detected fungicides in soil samples with azole-resistant fungus. Our study results suggest that managing the fungicides used in agriculture will help contain the problem of antifungal drug resistance in clinics. [ABSTRACT FROM AUTHOR]

A reliable and sensitive isotope-labelled internal standard method for simultaneous determination of chlorantraniliprole and cyantraniliprole in fruits (apple and grape), vegetables (cucumber and tomato) and cereals (rice and wheat) using ultra-high-performance liquid chromatography–tandem mass spectrometry was developed. Isotope-labelled internal standards were effective in compensating for the loss in the pretreatment and overcoming the matrix effect. The analytes were extracted with acetonitrile and cleaned up with different kinds of sorbents. The determination of the target compounds was achieved in less than 4 min using a T3 column combined with an electrospray ionization source in positive mode. The overall average relative recoveries in all matrices at three spiking levels (10, 20 and 50 μg kg-1) ranged from 95.5 to 106.2 %, with all relative standard deviations being less than 14.4 % for all analytes. The limits of detection did not exceed 0.085 μg kg-1 and the limits of quantification were below 0.28 μg kg-1 in all matrices. The method was demonstrated to be convenient and accurate for the routine monitoring of chlorantraniliprole and cyantraniliprole in fruits, vegetables and cereals. [ABSTRACT FROM AUTHOR]

An ultra-performance LC/tandem MS (UPLC/MS/MS) method for the simultaneous quantification and identification of matrine and berberine, alkaloids widely used in plant fungicides, has been developed and validated. Methanol or 1% ammonia-acetonitrile were selected as extraction solvents, and primary secondary amine sorbent was chosen for cleanup to achieve satisfactory recoveries in accordance with European Union guidelines. The chromatographic separation was carried out on a hydrophilic interaction LC column with a UPLC/MS/MS-based method to improve the retentions and shapes of the peaks. Method validation was performed for linearity, repeatability, interday precision, and sensitivity. Recoveries and RSDs were acceptable (73.1-109.3% recovery, RSD ≤ 15.8%). The LODs varied from 0.34 to 1.07 μg/kg for matrine and 0.09 to 0.18 µg/kg for berberine, while the LOQs ranged from 1.12 to 3.58 μg/kg for matrine and 0.31 to 0.60 μg/kg for berberine. This method was successfully and efficiently applied for the analysis of matrine and berberine in real samples. [ABSTRACT FROM AUTHOR]

In this study, the systemic assessments of the stereoisomers of triazole fungicide difenoconazole are reported for the first time, including absolute stereochemistry, stereoselective bioactivity toward pathogens (Alternaria sonali, Fulvia fulva, Botrytis cinerea, and Rhizoctonia solani), and toxicity toward aquatic organisms (Scenedesmus obliquus, Daphnia magna, and Danio rerio). Moreover, the stereoselective degradation of difenoconazole in vegetables (cucumber, Cucumis sativus and tomato, Lycopersicon esculentum) under field conditions and in soil under laboratory-controlled conditions (aerobic and anaerobic) was investigated. There were 1.33-24.2-fold and 1.04-6.78-fold differences in bioactivity and toxicity, respectively. Investigations on the stereoselective degradation of difenoconazole in vegetables showed that the highest-toxic and lowest-bioactive (2S,4S)-stereoisomer displays a different enrichment behavior in different plant species. Under aerobic or anaerobic conditions, (2R,4R)- and (2R,4S)-difenoconazole were preferentially degraded in the soil. Moreover, difenoconazole was configurationally stable in the test soil matrices. On the basis of biological activity, ecotoxicity, and environmental behavior, it is likely that the use of pure (2R,4S)-difenoconazole instead of the commercial stereoisomer mix may help to increase the bioactivity and reduce environmental pollution. [ABSTRACT FROM AUTHOR]

Fenbuconazole is a widely used systemic agricultural fungicide of the triazole class with one chiral center. In the present study, the enantioselective degradation of fenbuconazole and its chiral metabolites, RH-9129 and RH-9130, in two soils under aerobic and anaerobic conditions were investigated using a chiral OD-RH column on a reversed-phase liquid chromatography-tandem mass spectrometry system. Under aerobic or anaerobic conditions, the results showed the occurrence of enantioselectivity with (-)-fenbuconazole preferentially degraded in both soils. Further enantioselective analysis of converted products showed that the concentrations of four RH-9129 and RH-9130 stereoisomers were different from each other under both aerobic and anaerobic conditions. The four stereoisomer concentrations followed the order (-)-RH-9129 > (+)-RH-9129 > (-)-RH-9130 > (+)-RH-9130 in Langfang alkaline soil. However, in the case of Changsha acidic soil, different RH-9129 and RH-9130 stereoisomer patterns were produced in the order (-)-RH-9129 > (+)-RH-9129 > (+)-RH-9130 > (-)-RH-9130. The (-)-RH-9129 stereoisomer had the highest concentration formed by transformation of fenbuconazole in both soils. The degradation of RH-9129 and RH-9130 in the two soils is also stereoselective under both aerobic and anaerobic conditions, the results indicating that the (+)-RH-9130 enantiomer degraded faster than the (-)-RH-9130 enantiomer and the (+)-RH-9129 enantiomer degraded faster than the (-)-RH-9129 enantiomer. In addition, the (-)-RH-9129 isomer exhibited the slowest degradation rate in both soils. This study provides the first experimental evidence of stereoselective degradation and transformation of fenbuconazole as well as its chiral metabolites in the environment. [ABSTRACT FROM AUTHOR]

The article discusses a study which developed and validated a method for the simultaneous quantitative determination of aminopyralid, clopyralid and picloram in vegetables and fruits using ultra-performance liquid chromatography (LC) coupled with tandem mass spectrometry (MS). The herbicides used in the study were separated successfully and confirmed in a single run. It also used different extraction and cleanup methods to optimize the pretreatment processes of the residue analysis method.

rapid and simple miniaturized liquid-liquid extraction method has been developed for the determination of topramezone in soil, corn, wheat, and water samples using ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-electrospray ionization (ESI)/MS/MS). The established method for the extraction and purification procedure was based on liquid-liquid partitioning into an aqueous solution at a low pH (pH ≈ 2.5), followed by back-partitioning into water at pH > 9. Two precursor, product ion transitions for topramezone were measured and evaluated to provide the maximum degree of confidence in the results. Under negative ESI conditions, quantitation was achieved by monitoring the fragment at m/ z = 334 and the qualitative fragment at m/ z = 318, whereas also collecting the corresponding parent ion at m/ z = 362. Chromatographic separation was achieved using gradient elution with a mobile phase consisting of methanol and a 0.01% aqueous ammonium hydroxide solution. Recovery studies for soil, corn, wheat, and water were conducted at four different topramezone concentrations (5 or 10, 50, 100, and 1,000 μg kg); the overall average recoveries ranged from 79.9% to 98.4% with intra-day relative standard deviations (RSD) of 3.1~8.7% and inter-day RSD of 4.3~7.5%. Quantitative results were determined from calibration curves of topramezone standards containing 1-500 μg L with an R ≥ 0.9994. Method sensitivities expressed as limits of quantitation were typically 6, 8, 9, and 1 μg kg in soil, corn, wheat, and water, respectively. The results of the method validation confirmed that this proposed method was convenient and reliable for the determination of topramezone residues in soil, corn, wheat, and water. [Figure not available: see fulltext.] [ABSTRACT FROM AUTHOR]

sensitive and effective method for simultaneous determination of triazolopyrimidine sulfonamide herbicide residues in soil, water, and wheat was developed using ultra-performance liquid chromatography coupled with tandem mass spectrometry. The four herbicides (pyroxsulam, flumetsulam, metosulam, and diclosulam) were cleaned up with an off-line C18 SPE cartridge and detected by tandem mass spectrometry using an electrospray ionization source in positive mode (ESI+). The determination of the target compounds was achieved in <2.0 min. The limits of detection were below 1 μg kg, while the limits of quantification did not exceed 3 μg kg in different matrices. Quantitation was determined from calibration curves of standards containing 0.05-100 μg L with r > 0.997. Recovery studies were conducted at three spiked levels (0.2, 1, and 5 μg kg for water; 5, 10, and 100 μg kg for soil and wheat). The overall average recoveries for this method in water, soil, wheat plants, and seeds at three levels ranged from 75.4% to 106.0%, with relative standard deviations in the range of 2.1-12.5% ( n = 5) for all analytes. [ABSTRACT FROM AUTHOR]

Exhaustive hydro-distillation of Descurainia sophia (L.) Webb ex Prantl (flixweed) collected from two different locations (Cangzhou city-Sample 1 and Beijing city-Sample 2) gave in both cases yellowish colored oils in 0.31 and 0.26% yield, respectively. Detailed chemical composition of the essential oils was analyzed by GC and GC/MS, and forty and thirty-eight compounds were identified. The results indicated that the most abundant component of Sample 1 were cis-β-ocimene (20.1%), menthol (11.27%), neoisomenthyl acetate (3.5%), alloaromadendrene (2.28%) and longicyclene (2.25%). Compared with the constituents of Sample 1, several chemical compounds such as 1,8-cineole, α-eudesmol, cis, trans-farnesol and β-pinene were not detected in Sample 2 although it was similarly dominated by cis-β-ocimene (17.12%), menthol (10.7%) and neoisomenthyl acetate (2.96%). Final analysis of the chemical constituents in the essential oils of the two samples showed similarity in their chemical composition, but the relative content of all shared chemical constituents in Sample 2 was lower than that in Sample 1. [ABSTRACT FROM AUTHOR]

The dissipation of myclobutanil (triazole fungicide) in wheat plant, grain and soil under the local weather and soil conditions was studied and fungicide residues were determined by GC-ITMS. Myclobutanil (25% EC) was applied at two dosages, 60 g a.i. ha-1 (recommended) and 120 g a.i. ha-1 (2 times of the recommended dosage) in the experimental fields in Shandong, Beijing and Henan provinces (experimental localities). The detection limit (LOD) and the limit of quantification (LOQ) of myclobutanil were 0.6 µg kg-1 and 2 µg kg-1 respectively, and they were much below the maximum residue limit (MRL 0.02 mg kg-1) in the EU. The average recoveries were 76.4-97.7, 82.6-92.6 and 75.0-94.4% with relative standard deviation (RSD) of 6.3-15.9, 3.8-17.3 and 3.0-19.7% in wheat plant at four spiking levels (0.01, 0.1, 0.5, 10 mg kg-1), wheat grain at four spiking levels (0.005, 0.01, 0.1, 10 mg kg-1) and soil at five spiking levels (0.002, 0.01, 0.1, 0.5, 10 mg kg-1), respectively. The results showed that the half-lives of myclobutanil in wheat plant and soil from Shandong, Beijing and Henan were 3.5-4.5 and 11.0-11.7 days, respectively. At harvest, wheat grain samples were found to contain myclobutanil well below the MRL following the recommended dosage and the interval of 20 days after last application. [ABSTRACT FROM AUTHOR]

Residual pesticides in soil may be taken in by plants and thus have a risk for plant growth and food safety. In this study, uptake of triadimefon and its subsequent translocation and accumulation were investigated with wheat as model plants. The results from hydroponics indicated that triadimefon was absorbed by wheat roots mainly through apoplastic pathway and predominantly distributed into the water soluble fractions (66.7−76.0%). After being uptaken by roots, triadimefon was easily translocated upward to wheat shoots and leaves. Interestingly, triadimefon in leaves was mainly distributed in the soluble fraction by 52.5% at the beginning, and gradually transferred into the cell wall by 47.2% at equilibrium. The uptake of triadimefon from soils by wheat plants was similar to that in hydroponics. Its accumulation were mainly governed by adsorption of the fungicide onto soils, and positively correlated with its concentration in in situ pore water (C IPW). Thus, C IPW can be suitable for predicting the uptake of triadimefon by wheat from soils. Accordingly, uptake of triadimefon by wheat was predicted well by using the partition-limited model. Our study provides valuable information for guiding the practical application and safety evaluation of triadimefon. [Display omitted] • Triadimefon could be easily translocated upward to wheat leaves. • The subcellular distribution of triadimefon affected its translocation capacity. • Apoplastic pathways contributed to the uptake of triadimefon by wheat roots. • Concentration of triadimefon in in situ pore water can predict its uptake by wheat. [ABSTRACT FROM AUTHOR]