The accessibility, necessity, and significance of certified reference materials for total selenium content and its species to improve food laboratories' performance

Preparation and characterization of new reference material for inorganic analysis of pumpkin seed flour - An interlaboratory program

This work describes preparing a certified reference material for pumpkin seed flour for use in inorganic analyses of vegetable foods. The elements studied were potassium, magnesium, phosphorus, zinc, copper, iron, manganese, and calcium. The ISO Guides were employed in the homogeneity and stability tests, interlaboratory program, and assignment of uncertainty value. The material was stable for 12 months at temperatures of -10 °C, 25 °C, and 45 °C, with minor uncertainties. Chemometric techniques, such as principal component analysis (PCA) and hierarchical clustering analysis (HCA), were employed in the homogeneity and stability studies. The confidence ellipse technique allowed a simple and rapid evaluation of the data furnished by the collaborating laboratories regarding the precision of the results. The findings showed that pumpkin seed flour could be considered a raw material for preparing reference material, considering its availability and characteristics of its matrix, including the presence of trace and essential elements.

Advances in mycotoxin detection techniques and the crucial role of reference material in ensuring food safety. A review

Mycotoxins, toxic secondary metabolites produced by fungi, pose a significant threat to food safety and human health. The occurrence of mycotoxins in food commodities necessitates accurate and reliable detection methods. Advanced detection techniques, such as chromatographic techniques and immunochemical assays, have improved sensitivity and specificity. However, the lack of standardized reference material, particularly in less privileged countries, hinders method validation and proficiency testing, ultimately affecting mycotoxin testing and regulation. Moreover, these techniques are complex as they require specialized equipment, and well-trained personnel, thus limiting their practical applications. This comprehensive review provides an up-to-date overview of the occurrence of mycotoxins and recent advancements in detection methods. It examines the crucial role of mycotoxin standards as reference materials for ensuring reliable results in mycotoxins analysis in agriculture commodities. The review addresses emerging challenges, knowledge gaps, and future research directions in mycotoxin detection and reference material development. By synthesizing existing literature, this review aims to provide valuable resources for researchers, policymakers, and other stakeholders in food safety, highlighting the importance of integrated approaches to mitigate mycotoxin contamination and ensuring food safety.

Self-augmented catabolism mediated by Se/Fe co-doped bioceramics boosts ROS storm for highly efficient antitumor therapy of bone scaffolds

The overexpression of glutathione (GSH) within the tumor microenvironment has long been considered as the major obstacle for reactive oxygen species (ROS)-based antitumor therapies. To address this challenge, a selenite (SeO32 -) and ferric ion co-doped hydroxyapatite (SF-HAP) nanohybrid was synthesized, which is then introduced into poly-L-lactic acid (PLLA) to prepare porous scaffold by selective laser sintering to continuously release Fe3+ and SeO32- ions. Of great significance is the released SeO32- catabolize GSH to generate superoxide anion (O2•-) rather than directly eliminating GSH, thereby reversing the obstacle posed by its overexpression and achieving a "waste-to-treasure" transformation. The newly generated O2•- synergizes with the hydroxyl radicals (•OH) produced by the Fenton reaction between Fe3+/2+ and hydrogen peroxide, triggering high concentration ROS storms. Collectively, the PLLA/SF-HAP scaffold mediated self-augmented catabolism dynamic progress significantly raised intracellular ROS levels, almost twice as much as PLLA/Fe-HAP scaffold, thereby effectively inducing tumor cell apoptosis. The study provides an innovative inspiration for ROS-based antitumor therapies.

GATA3-COMT1-Melatonin as Upstream Signaling of ABA Participated in Se-Enhanced Cold Tolerance by Regulate Iron Uptake and Distribution in Cucumis sativus L

Selenium has the function of bio-stimulating hormone. However, the underlying physiological and molecular mechanisms of melatonin and abscisic acid as secondary messengers in improving cold tolerance by selenium are limited. This study investigated the effects of selenite on the cold stress of cucumber seedlings. The results showed that the content of endogenesis abscisic acid significantly changed with exogenous application of selenite under cold stress. Interestingly, we found that the content of iron significantly changed in this process. Iron uptake and distribution may be the important reason of selenium alleviates cold injury of cucumber seedlings. Whole genes transcriptome was used for screening key genes on leaf and root of cucumber seedlings. To determine the interrelation between abscisic acid and melatonin in selenite alleviating cold stress, abscisic acid inhibitor fluridone and melatonin synthesis inhibitor p-chlorophenylalanine were used for in-depth study. The results indicate that melatonin as upstream signal of ABA involved in selenium enhanced cucumber cold tolerance. The results of yeast single hybridization, EMSA, LUC, and overexpression transgenic showed that the transcription factor CsGATA3 regulates the expression of CsCOMT1 in vitro and in vivo and affects melatonin content. This study provides a theoretical basis for cucumber cultivation and breeding.

Multilayer Annotation Strategy AnnoSePS: Disentangling the Intricate Structure of Selenium-Containing Polysaccharides Based on Preferential Fragmentation Patterns

Precision mapping of selenium at structural and position levels poses significant challenges in selenium-containing polysaccharide identification. Due to the absence of reference spectra, database-centric approaches are still limited in the discovery of selenium binding sites and distinction among different isomeric structures. A multilayer annotation strategy, AnnoSePS, is proposed for achieving the identification of seleno-substituent and the unbiased profiling of polysaccharides. Applying Snoop-triggered multiple reaction monitoring (Snoop-MRM) identified multidimensional monosaccharides in selenium-containing polysaccharides. Galactose, galacturonic acid, and glucose were the predominant monosaccharides with a molar ratio of 25.19, 19.45, and 11.72, respectively. Selenium present in seleno-rhamnose was found to substitute the hydroxyl group located at C-1 positions through the formation of a Se-H bond. Ions C6H9O3Se-, C6H7O3Se-, C5H5O3Se-, C4H5O2Se-, C3H5O2Se-, C2H3O2Se-, and CHOSe- were defined as the characteristic fragments of seleno-rhamnose. The agglomerative hierarchical clustering algorithm is applied to group spectra from each run based on the characteristic information. Preferential fragmentation patterns in mass spectrometry are revealed by training a probabilistic model. A list of candidate oligosaccharides is generated by step-by-step browsing through the transition pairs for all reference spectra and applying the transitions (addition, insertion, removal, and substitution) to reference structures. Combining time course analyses revealed the linkage composition of selenium-containing oligosaccharides. Glycosidic linkages were annotated based on a synthesis-driven approach. T-Galactose (16.67 ± 5.23%) and T-Galacturonic acid (11.54 ± 4.66%) were the predominant linkage residues. As the database-independent mapping strategy, AnnoSePS makes it possible to comprehensively interrogate spectral data and dissect the fine structure of selenium-containing polysaccharides.

High Concentrations of Se Inhibited the Growth of Rice Seedlings

Selenium (Se) is crucial for both plants and humans, with plants acting as the main source for human Se intake. In plants, moderate Se enhances growth and increases stress resistance, whereas excessive Se leads to toxicity. The physiological mechanisms by which Se influences rice seedlings' growth are poorly understood and require additional research. In order to study the effects of selenium stress on rice seedlings, plant phenotype analysis, root scanning, metal ion content determination, physiological response index determination, hormone level determination, quantitative PCR (qPCR), and other methods were used. Our findings indicated that sodium selenite had dual effects on rice seedling growth under hydroponic conditions. At low concentrations, Se treatment promotes rice seedling growth by enhancing biomass, root length, and antioxidant capacity. Conversely, high concentrations of sodium selenite impair and damage rice, as evidenced by leaf yellowing, reduced chlorophyll content, decreased biomass, and stunted growth. Elevated Se levels also significantly affect antioxidase activities and the levels of proline, malondialdehyde, metal ions, and various phytohormones and selenium metabolism, ion transport, and antioxidant genes in rice. The adverse effects of high Se concentrations may directly disrupt protein synthesis or indirectly induce oxidative stress by altering the absorption and synthesis of other compounds. This study aims to elucidate the physiological responses of rice to Se toxicity stress and lay the groundwork for the development of Se-enriched rice varieties.

Eco-Friendly Spiking Approach Based on Microfluidics for Preparation of Matrix Reference Materials

Medicated bath is the most common spiking method used in the development of matrix reference materials for aquatic products; however, the environmental issues caused by the treatment of waste liquid after medicated bath cannot be ignored. We proposed an environmentally friendly spiking method based on microfluidics, which significantly improved the drug utilization rate without the need for subsequent drug residue treatment. Finely processed minced fish samples were fully mixed with quinolone drugs, and minced fish gel microspheres were prepared by microfluidic technology, utilizing the gel's water-locking function to enhance the drug-loading capacity. The results showed that this method can significantly increase the drug-loading capacity of the matrix (2.33-4.03 times) compared with the traditional spiking methods. In addition, the matrix reference material prepared by this method has good stability, and the drug concentration was adjustable and controllable.