Fast construction of core-shell structured magnetic covalent organic framework as sorbent for solid-phase extraction of zearalenone and its derivatives prior to their determination by UHPLC-MS/MS.

Magnetic covalent organic framework nanocomposite denoted as Fe3O4@TAPB-Tp with core-shell structure was fabricated via a simple template-mediated precipitation polymerization method at mild conditions. The polyimine network shell was created through the polymerization of 1,3,5-tris(4-aminophenyl)-benzene (TAPB) and 1,3,5-triformyl-phloroglucinol (Tp) in tetrahydrofuran (THF) by the Schiff-base reaction. Featuring with large specific surface area (163.19 m2 g-1), good solution dispersibility, and high stability, the obtained Fe3O4@TAPB-Tp exhibited high adsorption capacities and fast adsorption for zearalenone and its derivatives (ZEAs). The adsorption isotherms showed multilayer adsorption dominated at low concentration and monolayer adsorption at high concentration between the interface of ZEAs and Fe3O4@TAPB-Tp. With the Fe3O4@TAPB-Tp as sorbent, a magnetic solid-phase extraction-ultrahigh performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) method was established for simultaneous adsorption and detection of five ZEAs in complex samples. The proposed method displayed favorable linearity, low limits of detection (0.003 ~ 0.018 µg kg-1), and good repeatability (2.37~10.4%). The developed method has been applied for real sample analysis, with recoveries of 81.27~90.26%. These results showed that Fe3O4@TAPB-Tp has a good application potential for the adsorption of ZEAs in food samples. Magnetic covalent organic framework nanocomposite (Fe3O4@TAPB-Tp) were quickly fabricated at mild conditions and used as effective adsorbent for magnetic solid-phase extraction of zearalenone and its derivatives (ZEAs) from food samples prior to ultrahigh performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) analysis.

Research Progress on Fumonisin B1 Contamination and Toxicity: A Review.

Fumonisin B1 (FB1), belonging to the member of fumonisins, is one of the most toxic mycotoxins produced mainly by Fusarium proliferatum and Fusarium verticillioide. FB1 has caused extensive contamination worldwide, mainly in corn, rice, wheat, and their products, while it also poses a health risk and is toxic to animals and human. It has been shown to cause oxidative stress, endoplasmic reticulum stress, cellular autophagy, and apoptosis. This review focuses on the current stage of FB1 contamination, its toxic effects of acute toxicity, immunotoxicity, organ toxicity, and reproductive toxicity on animals and humans. The potential toxic mechanisms of FB1 are discussed. One of the main aims of the work is to provide a reliable reference strategy for understanding the occurrence and toxicity of FB1.

Sheep as a Potential Source of Zoonotic Cryptosporidiosis in China.

In this study, we assessed the prevalence and genetic characteristics of Cryptosporidium in sheep from 10 provinces in China. Fecal samples from 1,035 sheep originating from 16 farms were collected, and 295 (28.5%) were found to be Cryptosporidium positive by nested PCR. Cryptosporidium was detected at all farms, with infection rates between 5.7% and 50.0%. Three Cryptosporidium species were identified, including Cryptosporidium xiaoi (73.2%, 216/295), Cryptosporidium ubiquitum (21.7%, 64/295), and Cryptosporidium parvum (5.1%, 15/295). The distribution of Cryptosporidium species differed by province and by farm. All three species were detected in lambs and adult sheep but the highest infection rate was found in postweaned lambs. All three species were detected in all four seasons, with the highest prevalence found in autumn. Four C. parvum subtypes (IIaA15G2R1, IIaA17G2R1, IIdA18G1, and IIdA19G1) and one C. ubiquitum subtype (XIIa) were identified. For most provinces in this study, we are not aware of a previously published description or molecular characterization of Cryptosporidium infections in sheep. This information will improve our knowledge and understanding of the epidemiology of cryptosporidiosis in China.IMPORTANCECryptosporidium is an important zoonotic parasite that causes diarrhea in humans and animals worldwide. Previous studies suggested geographic differences in the distribution of Cryptosporidium species in sheep. However, molecular characterization studies of Cryptosporidium species in sheep have been carried out in only a few provinces in China, and the limited data available do not reflect the real situation. In this study, five districts, covering most areas where sheep are bred in China, were selected for examination of Cryptosporidium species, and Cryptosporidium infections were detected at all farms assessed, suggesting that Cryptosporidium is widespread in sheep in China. We also found geographic differences in the distribution of Cryptosporidium species but did not detect any differences between sheep age groups or seasons. Subtyping analyses showed that all of the subtypes identified in this study have been reported in humans, suggesting that sheep may be a potential source of zoonotic cryptosporidiosis.

Novel influenza A(H7N2) virus in chickens, Jilin province, China, 2014.

In February 2014, while investigating the source of a human infection with influenza A(H7N9) virus in northern China, we isolated subtypes H7N2 and H9N2 viruses from chickens on the patient's farm. Sequence analysis revealed that the H7N2 virus is a novel reassortant of H7N9 and H9N2 viruses. Continued surveillance is needed.

Exploring formation of turanose in honey via stable isotope labelling and high-resolution mass spectrometry analysis.

Turanose, an isomer of sucrose, naturally exists in honey. Previous study indicated that turanose content increased gradually in acacia honey as honeybees brewed honey in the hive. However, it is unclear how turanose is generated in honey. We hypothesised that turanose was produced by enzymes from honeybees and performed a series of simulation experiments to prove this hypothesis. We found turanose in honey was produced by honeybees processing sucrose. Furthermore, we determined that sugar composition of simulated nectar influenced the turanose concentration in honey: when sucrose concentration was below 5%, turanose was difficult to form, whereas high concentration of fructose and limited glucose were beneficial in producing turanose. Using 13C-labelled sucrose tests combined with proteomics analysis, we identified that α-glucosidase converted sucrose to turanose through an intermolecular isomerisation process. This study reveals the formation mechanism of turanose in honey and assists in the scientific control and improvement of honey quality.

Exploring the Formation of Chemical Markers in Chaste Honey by Comparative Metabolomics: From Nectar to Mature Honey.

Identification of chemical markers is important to ensure the authenticity of monofloral honey; however, the formation of chemical markers in honey has received little attention. Herein, using comparative metabolomics, we first identified chemical markers in chaste honey and then explored their formation and accumulation from nectar to mature honey. We identified agnuside and p-hydroxybenzoic acid glucosides as chemical markers for chaste honey. Besides, we developed an UHPLC-MS/MS method for quantifying these markers and found that their levels varied significantly across sample sources. We compared the presence of these compounds in chaste nectar and mature honey. The outcomes underscore that these characteristic compounds are not simply delivered from nectar to mature honey, and activities of honeybees (collecting and processing) play a pivotal role in their formation and accumulation. These observations shed light on how mature honey can form its unique qualities with a rich assortment of natural bioactive compounds, potentially supporting health benefits.

Chaste honey in long term-storage: Occurrence and accumulation of Maillard reaction products, and safety assessment.

Honey, a natural sweetener that can be stored long-term, is prone to Maillard reactions. Maillard reaction products (MRPs), such as 5-hydroxymethylfurfural (5-HMF), α-dicarbonyl compounds (α-DCs), and advanced glycation end products (AGEs), negatively affect human health. We analyzed MRP accumulation in chaste honey over four years. In the first year, α-DCs were dominant with total contents of 509.7 mg/kg. In the second year, Amadori compounds increased, accounting for the largest percentage. Their formation at the initial stage showed inhibition of the Maillard reaction over time. AGE contents were approximately 1.00 mg/kg over four years, which is negligible compared to other foods. Increased 5-HMF was significantly correlated with storage time (p < 0.01), making it a suitable indicator of honey quality. Due to the lack of MRP risk assessments, we compared our findings with daily intake of MRPs from other foods, and the levels of MRPs in honey over four years are acceptable.

Hydrophilic Covalent Organic Frameworks Coated Steel Sheet As a Mass Spectrometric Ionization Source for the Direct Determination of Zearalenone and Its Derivatives.

Zearalenone has attracted worldwide attention due to its toxic properties and threat to public health. A rapid determination method for zearalenone and its derivatives by hydrophilic covalent organic frameworks coated steel sheet (HCOFCS) combined with ambient mass spectrometry (AMS) was developed. The HCOFCS behaved as both a tip for solid-phase microextraction and a solid substrate for electrospray ionization mass spectrometry (ESI-MS). To evaluate the HCOFCS-ESI-MS method, five zearalenone and its derivatives in milk samples were determined, including zearalenone (ZEA), α-zearalenol (α-ZEL), ß-zearalenol (ß-ZEL), α-zearalanol (α-ZAL), and ß-zearalanol (ß-ZAL). After the extraction procedure, the HCOFCS was directly added with a high voltage for ESI-MS, and the analysis could be completed within 1 min. The developed method showed good linearity in the range 0.1-100 µg/L with a coefficient of determination (R2) > 0.9991. The limits of detection (LODs) and limits of quantitation (LOQs) ranged from 0.05 to 0.1 and 0.2 to 0.3 µg/L, respectively. The results demonstrated that the HCOFCS combined with ESI-MS can be used for the rapid and sensitive determination of trace ZEA and its derivatives in milk samples with satisfactory recoveries from 80.58% to 109.98% and reproducibility with relative standard deviations (RSDs) no more than 11.18%. Furthermore, HCOFCS showed good reusability, which could reuse at least 10 extraction cycles with satisfactory adsorption performance.

Rapid and sensitive determination of trace fluoroquinolone antibiotics in milk by molecularly imprinted polymer-coated stainless steel sheet electrospray ionization mass spectrometry.

Rapid analysis of trace analytes in complex biological samples is a great challenge for direct mass spectrometry, which suffers from low detection sensitivity. In this study, molecular imprinting technology was explored on the stainless steel sheet and integrated with the electrospray ionization method for direct sample analyses. The molecularly imprinted polymer-coated stainless steel sheet (MIPCS) was prepared and used as a solid-phase microextraction tip for rapid sampling of trace fluoroquinolone antibiotics in milk samples and then applied as an electrospray ionization tip to couple MS for sensitive detection. Our results shown that MIPCS could significantly enrich the trace fluoroquinolone antibiotics in milk samples. In our study, the extraction process of milk sample was completed within 30 min and the direct MS analysis was accomplished within 1 min. In addition, this proposed MIPCS-ESI-MS method showed a good linearity (R2>0.99) ranged from 1 to 1000 ng mL-1. The limits of detection (LODs) and limits of quantitation (LOQs) for the analytes range from 0.1 to 5 ng mL-1. The recoveries were in a range of 78.84%-103.04%. The relative standard deviation (RSD%) of inter-day and intra-day precision ranged from 7.00% to 10.4% and 4.46%-11.44% respectively. Overall, the proposed MIPCS-ESI-MS method could be feasibly used as a rapid and sensitive method for determination of trace analytes in complex food samples.

Prevalence and genotype of Toxoplasma gondii infection in cattle from Jilin Province, northeastern China.

Abstract The prevalence and genotype of Toxoplasma gondii infection in cattle in Jilin Province, northeastern China was investigated. A total of 1040 serum samples were collected from eight administrative regions from September to October, 2011, and antibodies to T. gondii were examined by enzyme-linked immunosorbent assay (ELISA). The results showed that the overall seroprevalence of T. gondii in cattle was 12.8% (95% confidence interval [CI], 10.8-14.8%), with a higher prevalence of 22.2% (95% CI 13.6-30.8%) in Siping. Sixty-six tissue samples were collected from Changchun, and T. gondii DNA was detected by a nested PCR. There were nine (13.6%; 95% CI 5.4-21.9%) positive samples, which were genotyped using 11 genetic markers for PCR restriction fragment length polymorphisms (RFLP). Only one sample could be completely genotyped, and all of the loci were grouped into clonal type I, except for type III at the GRA6 locus, implying that T. gondii in cattle in Changchun, Jilin Province was type I variant. This study is the first report on genotype of T. gondii infection in cattle in China.