Pesticide residues in agricultural end-products and risk assessment for consumers in North China.

This study investigated pesticide residues in market-sold vegetables and fruits in Hebei Province, China, over 5 years (2018-2022). A modified QuEChERS (Quick, Easy, Cheap, Effective, Rugged, and Safe) method was applied to gas chromatography with triple-quadrupole mass spectrometer (GC-MS/MS). The analytical methods were validated with respect to matrix effect (ME), recovery rate (78.9~105.5%), limit of quantitation (LOQ, 2.93~9.73 µg/kg), and linear correlation coefficient (0.9982~0.9997). Residues of 10 pesticides in 12 categories of vegetable and fruit were detected. 31.9% of the samples were detected pesticide residues; 15.5% of samples were detected multi-component pesticide residues. Twenty-seven positive detections of pesticide residues exceeded the corresponding maximum residue limit (MRL), accounting for 2.33%. The most types of pesticide residues were detected in cherry, with the number of 7. Procymidone was the most detected pesticide, and it was detected in 8 categories of samples. The hazard index (HI) of omethoate was the highest and the procymidone was the lowest. The HI of all the vegetables and fruits were less than 100%. The effects of pesticide residues are within an acceptable range for human. Adequate attention and further monitoring are still needed.

Rapid detection of antibiotic resistance genes in lactic acid bacteria using PMMA-based microreactor arrays.

The emergence of lactic acid bacteria (LABs) resistant to existing antimicrobial drugs is a growing health crisis. To decrease the overuse of antibiotics, molecular diagnostic systems that can rapidly determine the presence of antibiotic resistance (AR) genes in LABs from yogurt samples are needed. This paper describes a fully integrated, miniaturized plastic chip and closed-tube detection chemistry that performs multiplex nucleic acid amplification. High-throughput identification of AR genes was achieved through this approach, and six AR genes were analyzed simultaneously in < 2 h. This time-to-result included the time required for the extraction of DNA. The detection limit of the chip was 103 CFU mL-1, which was consistent with that of tube LAMP. We detected and identified multiple DNAs, including streptomycin, tetracycline, and vancomycin resistance-associated genes, with complete concordance to the Kirby-Bauer disk diffusion method.Key Points• A miniaturized chip was presented, and multiplex nucleic acid amplification was performed.• The device can be integrated with LAMP for rapid detection of antibiotic resistance genes.• The approach had a high throughput of AR gene analysis in lactic acid bacteria.

Changes in the gene expression profile of Arabidopsis thaliana under chromium stress.

Based on previous studies and preliminary test results, 200 µM was used as the test concentration of chromium (Cr), and changes in the gene expression profile of Arabidopsis thaliana in response to 24-h treatments of Cr(III) and Cr(VI) were analyzed using the Arabidopsis ATH1 Genome Array. The results were as follows. There were 238 upregulated genes and 858 downregulated genes in response to treatments with Cr(III) and Cr(VI). For Cr(III) and Cr(VI) treatments, there were 185 and 587 specifically upregulated genes as well as 220 and 956 specifically downregulated genes, respectively. Among the common differentially expressed genes (DEGs), the expression levels of genes involved in redox, secondary metabolism, and energy metabolism processes were significantly downregulated, while those of genes related to the stress response, photosynthesis, and sulfur metabolism were significantly upregulated. These findings indicated that Cr seriously affected the normal activities of A. thaliana cells. Some genes associated with stress and regulation were upregulated to adapt to the stress caused by Cr. Among the unique DEGs, the expression levels of genes involved in indole-3-acetic acid (IAA) regulatory pathway were significantly increased in response to Cr(III) treatment; the expression levels of genes involved in the abscisic acid (ABA) regulation pathway and carotenoid synthesis were significantly increased following Cr(VI) treatment. These results revealed some differences in response to Cr(III) and Cr(VI) in A. thaliana.

Mitigation of chromium toxicity in Arabidopsis thaliana by sulfur supplementation.

Chromium (Cr) contamination of soil and water has become a severe threat to human health. In this study, a series of experiments were conducted to examine the ameliorative effects of Cr toxicity, by exogenous 100 µM sodium sulfate. Our team has examined the plant growth, Cr content, chlorophyll, antioxidant index and soluble protein content, before and after the addition of sodium sulfate. The results showed that the addition of sulfur (S) can reduce the enrichment of Cr and the content of malonyldialdehyde (MDA) under Cr stress. After addition of S in the culture solution, the biomass and roots length of Arabidopsis thaliana increased under Cr stress. Furthermore, the content of chlorophyll, superoxide dismutase (SOD), peroxidase (POD), catalase (CAT), glutathione (GSH), and soluble protein increased with the addition of sulfur. Transmission electron microscope observation point to that the chloroplasts can be damaged in leaf. All data demonstrate that S supplementation should help to alleviate the negative effects caused by both Cr(III) and Cr(VI) on Arabidopsis thaliana.

Monitoring of pesticide residues levels in fresh vegetable form Heibei Province, North China.

In this study, 226 samples of seven types of domestic vegetables collected from several vegetable-growing regions in Hebei Province of China were tested for the presence of 38 different agricultural pesticides using a gas chromatograph equipped with electron capture and nitrogen phosphorus detectors. The aim of this study was to investigate the distribution of pesticides in main vegetables from Hebei Province. Results showed that, in 65.93% of the samples, no residues were found, 31.42% of the samples contained pesticide residues at or below the maximum residue levels (MRLs), and 2.65% of the samples contained pesticide residues above MRL. The most frequently detected pesticides were acephate (31), followed by cyhalothrin (15), bifenthrin (8), omethoate (6), isazophos (6), dimethoate (5), chlorpyrifos (2), and malathion (1). Some (1.33%) of the samples contained multiple residues. The results provide useful information on the current contamination status of a key agricultural area in North China, and points to the continuous monitoring and strict regulation of pesticide use on vegetables are necessary.

Bacterial contamination of medical face mask wearing duration and the optimal wearing time.

Introduction: Bacterial contamination is a critical parameter for how long a medical mask will be worn. Methods: In this study, we used the pour plate method to observe the total bacteria counts in used medical face masks. The bacterial community analysis was detected using bio-Mass spectrometry technology and 16SrRNA gene sequencing technology. The wearing time of the mask from 0.5 hours to 5 hours were studied. Results: These results shown that the total number of bacteria on the inside surface of the mask were higher than the outside. The total number of bacteria on the inner surface of masks worn for 0.5 h, 1 h 2 h, 4 h and 5 h was 69 CFU/m2,91.3 CFU/m2, 159.6 CFU/m2, 219 CFU/m2, and 879 CFU/m2, respectively. The total number of bacteria on the outside surface of masks worn for 0.5 h, 1 h 2 h, 4 h and 5 h was 60 CFU/m2, 82.7 CFU/m2, 119.8 CFU/m2, 200 CFU/m2, and 498 CFU/m2, respectively. The bacterial abundance obtained from bio-Mass spectrometry were consistent with the results of 16SrRNA sequencing. Both the methods discovered the maximum number of Neisseria followed by Corynebacterium species in mask worn 5 hours. The top 100 bacteria isolated from inside and outside surface of mask belong to 11 phyla. Conclusions: We analyzed bacterial penetration efficiency of the bacteria that were detected both on the inside and outside surface of the masks. In the top 10 bacteria, no bacteria were detected both inside and outside the mask worn for four hours, while 6 bacteria species were detected on the inside and outside of the mask after wearing for five hours. Bacterial penetration rates ranged from 0.74% to 99.66% for masks worn continuously for five hours, and the penetration rate of four strains exceeded 10% in the top 10 colonies. We recommend timely replacement of masks worn for more than four hours.

Monitoring of Aluminum content in food and assessment of dietary exposure of residents in North China.

Although the Chinese diet has become very abundant in the past 30 years, few people know that traditional Chinese diet is exposed to aluminium (Al). A total of 1232 samples were purchased during 2017-2019 and analysed for Al content with an inductively coupled plasma-mass spectrometry (ICP-MS) method. High Al levels were found in deep-fried dough sticks (mean 219 mg/kg), starch products (mean 84.5 mg/kg), and steam bread (mean 28.6 mg/kg). The average dietary Al exposure of residents in North China was 1.82 mg/kg bw/week, lower than the PTWI (provisional tolerable weekly intake). Deep-fried dough sticks (DFDS) are the main Al contributor in North China, providing 28.2% of the daily intake. The P95 dietary exposure to Al from DFDS was 2.3 mg/kg bw/week, exceeding the PTWI. Therefore, more attention should be paid to the health risk of exposure to Al from DFDS and starch products. Over-use of Al associated with food additives should be effectively controlled.

Antiviral activity of sophoridine against enterovirus 71 in vitro.

ETHNOPHARMACOLOGICAL RELEVANCE: Enterovirus 71 (EV71) has a propensity to cause hand-foot-and-mouth disease (HFMD) epidemics associated with neurological sequelae. Unfortunately, no drugs are currently available for the clinical treatment of EV71 infections. Sophoridine (SRI) is one of the most abundant alkaloids in Sophora flavescens Aiton (Leguminosae), which has been used to treat fever, throat inflammation, cancer, and other diseases. MATERIALS AND METHODS: In this study, we found that SRI inhibits EV71 infection in Vero cells. To study the antiviral activity of SRI, Vero cells were divided into 3 treatment groups based on the timing of SRI dosing: prior to viral adsorption (Group A), during viral adsorption (Group B), and after viral adsorption (Group C). We further revealed the antiviral activity of SRI with the attachment assay and the penetration assay. For Group A, 50% viability of Vero cells was observed at a SRI concentration of 61.39 µg/mL, whereas for Groups B, 50% viability was observed at SRI concentrations of 196.86 µg/mL. Furthermore, 29.7% cell viability was observed even at a SRI concentration of 1000 µg/mL in Groups C. The results show that SRI was highly effective against EV71 when Vero cells were pretreated with SRI for 2 h (Group A). Further researches indicate SRI was highly effective at inhibiting EV71 attachment when the SRI concentrations over 250 µg/mL (P < 0.001). CONCLUSIONS: We have shown that Vero cell viability increases when SRI is administered prior to viral adsorption. This suggests that SRI has the considerable potential as an antiviral for EV71 disease prevention.

Sophocarpine against enterovirus 71 in vitro.

Sophocarpine (SCA) is a bioactive alkaloid present in Sophoraflavescens Ait. The present study demonstrated that SCA inhibited enterovirus 71 (EV71) infection in Vero cells. The results indicated that the 50% cytotoxicity concentration of SCA for Vero cells was 1,346 µg/ml, and the 50% inhibition concentration of SCA against EV71 was 350 µg/ml. SCA produced a marked inhibitory effect against EV71 when the Vero cells were treated with SCA prior to infection with the virus. Additionally, SCA was effective against EV71 when the Vero cells were infected with EV71 (100xTCID50) that had been treated with SCA for 2 h, and was effective when the Vero cells were infected with EV71 (100xTCID50) at 37°C under 5% CO2 for 2 h prior to treatment with SCA for 2 h. SCA was demonstrated to inhibit the attachment and penetration of EV71 and was more effective at inhibiting attachment. The assay additionally verified that SCA suppressed the replication of viral genomic RNA and indicated that SCA may inhibit EV71 infection in vitro.