Flowerlike Ni-NiO composite as magnetic solid-phase extraction sorbent for analysis of carbendazim and thiabendazole in edible vegetable oils by liquid chromatography-mass spectrometry.

A rapid, selective, and sensitive method was developed for the detection of carbendazim and thiabendazole in edible vegetable oil. Two benzimidazole analytes were pre-concentrated by magnetic solid phase extraction (MSPE) using flowerlike Ni-NiO composite as sorbents and followed by LC-MS/MS analysis. The flowerlike Ni-NiO composite sorbent displayed a high affinity towards benzimidazole analytes due to the reversible coordination interaction between the Ni(Ⅱ) ion and the electron-donating imidazole group. In comparison to the previous methods, this procedure is less time-consuming and simpler during sample preparation. The parameters affecting the extraction efficiency were optimized in detail. The method was validated according to SANTE/12682/2019. The limits of detection were in the range of 0.001-0.003 mg•kg-1. The recoveries ranged from 89.3% to 110.7% with inter-day and inter-day precision less than 10.9%. The results indicate that flowerlike Ni-NiO composite might be a promising alternative for MSPE of benzimidazole compounds in foods.

Rapid and Sensitive Detection of Aflatoxin B1, B2, G1 and G2 in Vegetable Oils Using Bare Fe3O4 as Magnetic Sorbents Coupled with High-Performance Liquid Chromatography with Fluorescence Detection.

This paper reports a simple, sensitive and reliable method for the simultaneous detection of aflatoxin B1, B2, G1 and G2 in vegetable oils. Aflatoxins were extracted by magnetic solid phase extraction followed by high-performance liquid chromatography, then postcolumn photochemical derivatization and finally detected by fluorescence detector. Vegetable oil samples were first diluted with hexane and then commercial bare Fe3O4 nanoparticles were directly employed as sorbents to extract aflatoxins from complex vegetable oil samples, which significantly simplified the procedure of sample preparation and largely improved the sample analysis throughput. The effects of various parameters such as the amount of sorbent, loading, washing and eluting conditions were carefully optimized to improve the extraction efficiencies of aflatoxins. Under the optimal conditions, the limits of detection of four aflatoxins ranged from 0.01 µg/kg to 0.16 µg/kg, and squared regression coefficients (R2) >0.9990 were obtained within the linear range of 0.1-20 µg/kg (except for aflatoxin G2 with 0.5-20 µg/kg). Furthermore, the recoveries spiked at four concentration levels in a blank vegetable oil sample were from 82.6 to 106.2%, with inter- and intraday relative standard deviations <9.8%, indicating good accuracy and precision of the proposed method.

Insights into Monascus biology at the genetic level.

The genus of Monascus was nominated by van Tieghem in 1884, but its fermented product-red mold rice (RMR), namely red yeast rice, has been used as folk medicines, food colorants, and fermentation starters for more than thousands of years in oriental countries. Nowadays, RMR is widely developed as food supplements around the world due to its functional compounds such as monacolin K (MK, also called lovastatin) and γ-aminobutyric acid. But the usage of RMR also incurs controversy resulting from contamination of citrinin (a kind of mycotoxin) produced by some Monascus strains. In the past decade, it has made great progress to Monascus spp. at the genetic level with the application of molecular biology techniques to restrain the citrinin production and increase the yields of MK and pigment in RMR, as well as aid Monascus classification and phylogenesis. Up to now, hundreds of papers about Monascus molecular biology (MMB) have been published in the international primary journals. However, to our knowledge, there is no MMB review issued until now. In this review, current understanding of Monascus spp. from the view of molecular biology will be covered and insights into research areas that need to be further investigated will also be discussed.

Waterborne exposure to microcystin-LR alters thyroid hormone levels and gene transcription in the hypothalamic-pituitary-thyroid axis in zebrafish larvae.

Microcystin-leucine-arginine (MCLR) is the most toxic and the most commonly encountered variant of microcystins (MCs) in aquatic environment, and it has the potential for disrupting thyroid hormone homeostasis, but the molecular mechanisms underlying this process have not yet been clarified. In the present study, we observed body growth retardation associated with decreased levels of thyroid hormones (THs) in zebrafish larvae, highlighting the interferences of MCLR with the growth of fish larvae. To further our understanding of mechanisms of MCLR-induced endocrine toxicity, quantitative real-time PCR analysis was performed on hypothalamic-pituitary-thyroid (HPT) axis related genes of developing zebrafish embryos exposed to 100, 300 and 500 µg L(-1) MCLR until 96 h post-fertilization. The expression of several genes in the HPT system, i.e., corticotropin-releasing factor (CRF), thyroid-stimulating hormone (TSH), sodium/iodide symporter (NIS), thyroglobulin (TG), thyroid receptors (TRα and TRß) and iodothyronine deiodinases (Dio1 and Dio2) was examined using quantitatively real-time PCR. The gene expression levels of CRF, TSH, NIS and TG were significantly induced after exposure to 500 µg L(-1) MCLR. The transcription of TRs gene was down-regulated in a concentration-dependent manner. Up-regulation and down-regulation of Deio1 and Deio2 gene expression, respectively, were observed upon exposure to MCLR. The above results indicated that MCLR could alter gene expression in the HPT axis which might subsequently contribute to MCLR-induced thyroid disruption.