FAM Tag Size Separation-Based Capture-Systematic Evolution of Ligands by Exponential Enrichment for Sterigmatocystin-Binding Aptamers with High Specificity.

Sterigmatocystin (ST) is a known toxin whose aptamer has rarely been reported because ST is a water-insoluble small-molecule target with few active sites, leading to difficulty in obtaining its aptamer using traditional target fixation screening methods. To obtain aptamer for ST, we incorporated FAM tag size separation into the capture-systematic evolution of ligands by exponential enrichment and combined it with molecular activation for aptamer screening. The screening process was monitored using a quantitative polymerase chain reaction fluorescence amplification curve and recovery of negative-, counter-, and positive-selected ssDNA. The affinity and specificity of the aptamer were verified by constructing an aptamer-affinity column, and the binding sites were predicted using molecular docking simulations. The results showed that the Kd value of the H Seq02 aptamer was 25.3 nM. The aptamer-affinity column based on 2.3 nmol of H Seq02 exhibited a capacity of about 80 ng, demonstrating better specificity than commercially available antibody affinity columns. Molecular simulation docking predicted the binding sites for H Seq02 and ST, further explaining the improved specificity. In addition, circular dichroism and isothermal titration calorimetry were used to verify the interaction between the aptamer and target ST. This study lays the foundation for the development of a new ST detection method.

The effect of choice on memory across development.

Numerous studies have demonstrated the role of making choices as an internal motivator to improve performance, and recent studies in the domain of memory have focused on adults. To chart the developmental trend of the choice effect on memory, we conducted a series of seven experiments involving children, adolescents, and young adults. Participants (N = 512) aged 5 to 26 years performed a choice encoding task that manipulated the opportunities to choose and then took a memory test. Using different types of experimental materials and corroborated by a mini meta-analysis, we found that the choice effect on memory was significant in childhood and early adolescence but not significant in late adolescence and early adulthood. The developmental changes were statistically significant, particularly evident during the transition from early to late adolescence. These findings suggest that the internal value of choice decreases across development and contributes to our understanding of developmental differences in the role of choice in memory.

Rapid, Simultaneous, and Automatic Determination of Lead and Cadmium in Cereals with a New High Performance Composite Hollow Cathode Lamp Coupled to Graphite Furnace Atomic Absorption Spectrometry.

A simple, rapid, sensitive, accurate, and automatic graphite furnace atomic absorption spectrometry (GFAAS) method for detecting Cd and Pb in cereals is presented. This method enables the simultaneous determination of Cd and Pb in cereals with a pre-treatment method of diluted acid extraction and a high-performance lead-cadmium composite hollow-cathode lamp (LCC-HCL), and it realizes automatic determination from sample weighing to result output through an automatic diluted acid extraction system. Under the optimization, Pb and Cd in cereals were simultaneously and automatically detected in up to 240 measurements in 8 h. The LOD and LOQ of this method were 0.012 and 0.040 mg·kg-1 for Pb, and 0.0014 and 0.0047 mg·kg-1 for Cd, respectively. The results of the four certified reference materials were satisfied; there was no significant difference compared with the ICP-MS method according to a t-test, and the RSDs were less than 5% for Cd and Pb. The recoveries of naturally contaminated samples compared with the ICP-MS method were favorable, with 80-110% in eight laboratories. The developed method is rapid, low-cost, and highly automated and may be a good choice for grain quality discrimination and rapid analysis of Cd and Pb in different institutions.

Copper Oxide Nanoparticle-Based Immunosensor for Zearalenone Analysis by Combining Automated Sample Pre-Processing and High-Throughput Terminal Detection.

A rapid and high-throughput fluorescence detection method for zearalenone (ZEN) based on a CuO nanoparticle (NP)-assisted signal amplification immunosensor was developed using an automated sample pretreatment and signal conversion system. CuO NPs with high stability and biocompatibility were used as carriers to immobilize anti-ZEN antibodies. The obtained CuO NP-anti-ZEN can maintain the ability to recognize target toxins and act as both a signal source and carrier to achieve signal conversion using automated equipment. In this process, target toxin detection is indirectly transformed to Cu2+ detection because of the large number of Cu2+ ions released from CuO NPs under acidic conditions. Finally, a simple and high-throughput fluorescence assay based on a fluorescent tripeptide molecule was employed to detect Cu2+, using a multifunctional microporous plate detector. A good linear relationship was observed between the fluorescence signal and the logarithm of ZEN concentration in the range of 16.0-1600.0 µg/kg. Additionally, excellent accuracy with a high recovery yield of 99.2-104.9% was obtained, which was concordant with the results obtained from LC-MS/MS of naturally contaminated samples. The CuO NP-based assay is a powerful and efficient screening tool for ZEN detection and can easily be modified to detect other mycotoxins.

The influence of rewards on incidental memory: more does not mean better.

Studies have revealed that rewards promote long-term memory, even in an incidental way. However, most previous studies using the incidental paradigm have included two reward levels, and it is still not clear how the reward magnitude influences memory. Adopting the incidental paradigm and three reward levels, the current study revealed that the reward magnitude impacted 1-d delayed episodic memory in a nonlinear, inverted U-shaped pattern. An additional experiment showed that there was no reward effect in immediate episodic memory. Our results support the dopaminergic memory consolidation theory and further imply that the reward magnitude needs to be considered in the theory.

Reliable and disposable quantum dot-based electrochemical immunosensor for aflatoxin B1 simplified analysis with automated magneto-controlled pretreatment system.

An integrated aflatoxin B1 (AFB1) detection platform with quantum dot (QD)-based electrochemical immunosensor and an automated magneto-controlled pretreatment system was successfully developed. The automated pretreatment system adopts the immunoaffinity magnetic beads (IMB) as the capture probe of AFB1 and QD-labeled AFB1 complete antigen (AFB1-BSA-QDs) as the signal probe. AFB1-BSA-QDs can be easily converted into corresponding metallic cations through acidic treatment, which can be detected electrochemically via anode stripping voltammetry (ASV). Moreover, a disposable screen-printed electrode (SPE) without requiring any further modification is used in the novel electrochemical immunosensor' making routine testing feasible. Under optimal conditions, the detectable concentration range of AFB1 was 0.08-800 µg/kg. The metal ion signal associated linearly with the logarithm of AFB1 concentration within the range of 5-240 µg/kg, with a detection limit of 0.05 µg/kg. The spiked recoveries of three different concentrations in four different matrixes ranged from 83.9 to 118.0%, and inter-day relative standard deviations were below 10%. Furthermore, the methodology was validated by analyzing naturally contaminated samples, and results of the novel immunosensor were in good agreement with those of LC-MS/MS, demonstrating the potentiality of the developed method for the monitor of AFB1 in cereals and oils.

An aptamer affinity column for purification and enrichment of aflatoxin B1 and aflatoxin B2 in agro-products.

We have developed an aptamer affinity column (AAC) for the purification and enrichment of trace aflatoxin B1 (AFB1) and aflatoxin B2 (AFB2) in genuine agro-products through the covalent conjugation of amino modified aptamer and NHS-activated Sepharose. The coupling and working conditions found to be suitable for this AFB-AAC were examined in regard to coupling time (2 min), loading volume (30 mL), and the methanol concentration (< 10%) used in the loading step. The performance of AFB-AAC was then further evaluated in terms of capacity (329.1 ± 13.7 ng for AFB1 and 162.5 ± 8.9 ng for AFB2), selectivity (excellent), reusability (twenty-three times for AFB1 and twelve times for AFB2), and repeatability (92.7% ± 2.9% for AFB1 and 71.5% ± 3.4% for AFB2). Furthermore, the AAC clean-up combined with HPLC-FLD demonstrated excellent linearity over a wide range, good sensitivity with an LOD of 50 pg mL-1 for AFB1 and 15 pg mL-1 for AFB2, and acceptable recovery with different spiking levels in different matrices. Finally, the AAC was successfully applied to analyte AFB1 and AFB2 in four types of agro-products as well as a maize flour reference material, and the results were found to be in accordance with those of commercial IACs. This study provides a reference for the analysis of other trace analytes by merely changing the corresponding aptamer and represents a strong contender for immune affinity columns. Graphical abstract An aptamer affinity column for purification and enrichment of aflatoxin B1 and aflatoxin B2 in agro-products with the aid of HPLC-FLD and a post-column photochemical derivatization reactor.

4-Bromodiphenyl Ether Causes Adrenal Gland Dysfunction in Rats during Puberty.

Polybrominated diphenyl ethers (PBDEs) are a group of flame retardants with two or more bromines attached. They are endocrine disruptors. PBDEs photodegrade into 4-bromodiphenyl ether (BDE3). Whether BDE3 impairs adrenal cortical cell function during postnatal development still remains unknown. The aim of the current study was to investigate the influence of BDE3 on adrenal cortical cell function. Sprague-Dawley rats (35 days of age, male) were orally administered with BDE3 (0, 50, 100, and 200 mg/kg/day body weight) for 21 days. BDE3 significantly increased serum aldosterone and corticosterone levels at 200 mg/kg without affecting adrenocorticotropic hormone level. Further study showed that BDE3 up-regulated Cyp11b1 at 100 and 200 mg/kg and Scarb1, Star, Cyp11b2, Cyp21, and Nr5a1 mRNA levels in the 200 mg/kg group. BDE3 also decreased the phosphorylation of AMP-activated protein kinase (AMPK) at 200 mg/kg and increased PGC-1α and phosphorylated cyclic AMP-responsive element-binding protein (CREB)/CREB at 200 mg/kg. Taken together, these findings demonstrate that BDE3 stimulates adrenal cell function likely through decreasing phosphorylation of AMPK and increasing phosphorylation of CREB.

A pretreatment-free and eco-friendly rapid detection for mycotoxins in edible oils based on magnetic separation technique.

Pretreatment steps of current rapid detection methods for mycotoxins in edible oils not only restrict detection efficiency, but also produce organic waste liquid to pollute environment. In this work, a pretreatment-free and eco-friendly rapid detection method for edible oil is established. This proposed method does not require pretreatment operation, and automated quantitative detection could be achieved by directly adding oil samples. According to polarity of target molecules, the content of surfactant in reaction solutions could be adjusted to achieve the quantitative detection of AFB1 in peanut oil and ZEN in corn oil. The recoveries are between 96.5%-110.7% with standard deviation <10.4%, and the limit of detection is 0.17 µg/kg for AFB1 and 4.91 µg/kg for ZEN. This method realizes full automation of the whole chain detection, i.e. sample in-result out, and is suitable for the on-site detection of batches of edible oils samples.

ChatGPT-based meta-analysis for evaluating the temporal and spatial characteristics of deoxynivalenol contamination in Chinese wheat.

Deoxynivalenol (DON) is a major source of mycotoxins in wheat. However, there is a lack of systematic reporting of the overall contamination status in China, hindering comprehensive assessments. In this study, we utilized a meta-analysis approach based on ChatGPT to systematically analyze DON contamination in wheat-growing regions in China, as reported in the literature from 2010 to 2021. By optimizing the query processes and refining the methodology keywords using ChatGPT, efficient screening, data identification, and literature extraction were achieved for the first time during the meta-analysis data acquisition phase. The matching rates for the screening and extraction of 1091 articles were 100 % and 95.4 %, respectively, resulting in a 20.5-fold work efficiency increase compared to that by manual operations. Meta-subgroup analysis by province and year revealed significant spatiotemporal heterogeneity in DON contamination in the wheat-growing regions of China. Furthermore, the relationship between climate factors and DON levels in wheat was investigated to illustrate the spatial and temporal heterogeneity of DON in Chinese wheat. The results showed that DON concentrations were mainly influenced by relative humidity and precipitation during the wheat-growing season. This novel ChatGPT-assisted meta-analysis approach provides valuable insights and offers a promising method for efficient meta-analyses in other fields.

One-pot green synthesis of ZIF-8/IgG composite for the precise orientation and protection of antibody and its application in purification and detection of aflatoxins in peanut oil.

This study presents a novel approach toward the one-pot green synthesis of ZIF-8/IgG composite, focusing on its precise orientation and protection of the anti-aflatoxins antibody. The antibody orientation is achieved through the specific binding of IgG to the Fc region of the antibody, while the antibody protection is accomplished by the structural change restriction of ZIF-8 framework to the antibody. Consequently, the antibody exhibits enhanced target capability and significantly improved tolerance to organic solvents. The ZIF-8/IgG/anti-AFT was employed for the purification and detection of AFTs by coupling with UPLC. Under optimized conditions, the recoveries of spiked AFTs in peanut oils are between 86.1% and 106.4%, with relative standard deviations (RSDs) ranging from 0.8% to 8.8%. The linearity range is 0.5-20.0 ng for AFB1 and AFG1, 0.125-5.0 ng for AFB2 and AFG2, the limit of detection is 0.1 ng for AFB1 and AFG1, 0.03 ng for AFB2 and AFG2.

Studies on adsorption properties of magnetic composite prepared by one-pot method for Cd(II), Pb(II), Hg(II), and As(III): Mechanism and practical application in food.

A one-pot synthesis afforded a magnetic, crosslinked polymer adsorbent (m-P6) with a variety of functional groups to realize simultaneous adsorption of Cd2+, Pb2+, Hg2+, and As3+. The material was characterized by TEM-EDS, XRD, FT-IR, VSM, and XPS. Kinetic and isothermal analyses suggested mainly chemisorption processes of heavy metal ions that form multiple layers on heterogeneous surfaces. Theoretical adsorption capacities calculated by a pseudo-2nd-order kinetic model and the Sips isothermal model were 282.88 mg/g for Cd2+, 326.18 mg/g for Pb2+, 117.85 mg/g for Hg2+, and 320.29 mg/g for As3+. m-P6 not only can efficiently adsorb divalent heavy metals (Cd2+, Pb2+, Hg2+), but also demonstrate a process of adsorption-driven catalytic oxidation by single-electron transfer (SET) from As3+ to As5+. In application, in addition to adsorption in water, m-P6 is capable of minimizing matrix interference, and extracting trace heavy metals in a complex environment (cereal) through easy operations for improving the detection accuracy, as well as it is potential for application in detection of trace heavy metals in foodstuffs. m-P6 can be readily regenerated and efficiently recycled for 5 cycles using eluent E12 and dilute acid.

Biotransformation of Deoxynivalenol by a Dual-Member Bacterial Consortium Isolated from Tenebrio molitor Larval Feces.

In this study, a dual-member bacterial consortium with the ability to oxidize deoxynivalenol (DON) to 3-keto-DON, designated SD, was first screened from the feces of Tenebrio molitor larvae. This consortium consisted of Pseudomonas sp. SD17-1 and Devosia sp. SD17-2, as determined by 16S rRNA-based phylogenetic analysis. A temperature of 30 °C, a pH of 8.0-9.0, and an initial inoculum concentration ratio of Devosia to Pseudomonas of 0.1 were optimal single-factor parameters for the DON oxidation activity of the bacterial consortium SD. Genome-based bioinformatics analysis revealed the presence of an intact PQQ biosynthesis operon (pqqFABCDEG) and four putative pyrroloquinoline quinone (PQQ)-dependent alcohol dehydrogenase (ADH) genes in the genomes of Pseudomonas strain SD17-1 and Devosia strain SD17-2, respectively. Biochemical analyses further confirmed the PQQ-producing phenotype of Pseudomonas and the DON-oxidizing enzymatic activities of two of four PQQ-dependent ADHs in Devosia. The addition of PQQ-containing a cell-free fermentation supernatant from Pseudomonas activated DON-oxidizing activity of Devosia. In summary, as members of the bacterial consortium SD, Pseudomonas and Devosia play indispensable and complementary roles in SD's oxidation of DON. Specifically, Pseudomonas is responsible for producing the necessary PQQ cofactor, whereas Devosia expresses the PQQ-dependent DON dehydrogenase, together facilitating the oxidation of DON.

Quantitative PCR assays for the species-specific detection of Fusarium graminearum sensu stricto and Fusarium asiaticum in winter wheat growing regions in China.

Fusarium graminearum species complex (FGSC) is one of the most devastating fungal plant pathogens of cereal crops worldwide, resulting in a corresponding mycotoxins contamination in cereal-based food. The detection of FGSC to study its population structure and species distribution is of great concern for the integrated control of mycotoxins contamination in grains entering food supply chains. In this study, real time quantitative PCR (RT-qPCR) and droplet digital PCR (ddPCR) methods were developed for the species-specific detection of Fusarium graminearum species complex in winter wheat growing regions in China. Primers and probes were designed basing the on the sequence of Fg-16 SCAR fragment (sequence characterized amplified regions analysis) and confirmed to make a distinguishment between the two prevailing species including Fusarium graminearum sensu stricto and Fusarium asiaticum. The assay specificity was tested against 24 isolates of target Fusarium species and several non-target Fusarium species that were frequently isolated from wheat in China. Consistent results could be obtained by the developed RT-qPCR and ddPCR assays, and both of them were sensitive enough for the detection of FGSC in these regions. Population structure and species distribution of FGSC in North China plain and Yangtze River plain by the developed qPCR assays accorded with previous results obtained by fungal isolation method. The newly developed qPCR assays are time-saving and will provide new insights during the routine surveillance of FGSC in winter wheat growing regions in China and possibly other countries.

A Study of a New Certified Reference Material for Accurate Determination of the Main Fusarium Mycotoxins in Whole-Wheat Flour.

Matrix certified reference materials (CRMs) play a critical role in analytical method validation and the assurance of reliable measurement results. A certified reference material (GBW(E)100813) for whole-wheat flour was developed to ensure an accurate and reliable measurement of the main Fusarium mycotoxins (deoxynivalenol (DON), nivalenol (NIV), deoxynivalenol-3-glucoside (DON-3G), and zearalenone (ZEN)). CRM candidates were prepared using sun-drying, grinding, sieving, homogenising, packaging, and gamma irradiation. The final produced CRM was packaged at 50 g per unit and stored at 20 °C. Certification was performed using isotope dilution-liquid chromatography-tandem mass spectrometry. CRM characterization was performed in eight laboratories in accordance with the requirements of ISO Guide 35. The certified values and expanded uncertainties (at a confidence of 95%, k = 2) for DON, NIV, DON-3G, and ZEN were determined to be 0.98 ± 0.12 mg/kg, 1.37 ± 0.20 mg/kg, 242 ± 35 µg/g, and 382 ± 50 µg/g. The CRM was sufficiently homogeneous between and within bottles, and remained stable for up to 12 months at 20 °C and 9 days below 40 °C for transportation. Thus, CRM can be used for quality control and method validation to ensure the accurate and reliable quantification of the main Fusarium mycotoxins in whole-wheat flour.

Development of a Novel Magnetic-Bead-Based Automated Strategy for Efficient and Low-Cost Sample Preparation for Ochratoxin A Detection Using Mycotoxin-Albumin Interaction.

The mycotoxin ochratoxin A (OTA) is toxic to humans and frequently contaminates wine and beer. Antibodies are essential recognition probes for the detection of OTA. However, they have several drawbacks, such as high costs and difficulty in preparation. In this study, a novel magnetic-bead-based automated strategy for efficient and low-cost OTA sample preparation was developed. Human serum albumin, which is an economical and stable receptor based on the mycotoxin-albumin interaction, was adapted and validated to replace conventional antibodies to capture OTA in the sample. Ultra-performance liquid chromatography-fluorescence detection was used in combination with this preparation method for efficient detection. The effects of different conditions on this method were investigated. The recovery of OTA samples spiked at three different concentrations ranged from 91.2% to 102.1%, and the relative standard deviations (RSDs) were 1.2%-8.2% in wine and beer. For red wine and beer samples, the LODs were 0.37 and 0.15 µg/L, respectively. This reliable method overcomes the drawbacks of conventional methods and offers significant application prospects.

Degradation of cyanobacterial neurotoxin ß-N-methylamino-L-alanine (BMAA) using ozone process: influencing factors and mechanism.

ß-N-methylamino-L-alanine (BMAA), which has been considered as an environmental factor that caused amyotrophic lateral sclerosis/parkinsonism-dementia complex (ALS/PDC) or Alzheimer's disease, could be produced by a variety of genera cyanobacteria. BMAA is widely present in water sources contaminated by cyanobacteria and may threaten human health through drinking water. Although oxidants commonly used in drinking water plants such as chlorine, ozone, hydrogen peroxide, and hydroxyl radicals have been shown to effectively degrade BMAA, there are limited studies on the mechanism of BMAA degradation by different oxidants, especially ozone. This work systematically explored the effectiveness of BMAA ozonation degradation, investigated the effect of the operating parameters on the effectiveness of degradation, and speculated on the pathways of BMAA decomposition. The results showed that BMAA could be quickly eliminated by ozone, and the removal rates of BMAA were nearly 100% in pure water, but the removal rates were reduced in actual water. BMAA was primarily degraded by direct oxidation of ozone molecules in acidic and near-neutral conditions, and indirect oxidation of •OH accounted for the main part under strong alkaline conditions. The pH value had a significant effect on the decomposition of BMAA, and the degradation rate of BMAA was fastest at near-neutral pH value. The degradation rates of TOC were significantly lower than that of BMAA, indicating that by-products were generated during the degradation process. Three by-products ([M-H]+ = 105, 90, and 88) were identified by UPLC-MS/MS, and the degradation pathways of BMAA were proposed. The production of by-products was attributed to the fracture of the C-N bonds. This work is helpful for the in-depth understanding on the mechanism and demonstration of the feasibility of the oxidation of BMAA by the ozone process. HIGHLIGHTS: • The reaction of ozonation BMAA was easy to occur. • The degradation rate was fast under near-neutral conditions. • Direct oxidation under neural conditions was the main pathway for ozone degradation of BMAA. • Three products were detected, and the reaction path was inferred.

Four PQQ-Dependent Alcohol Dehydrogenases Responsible for the Oxidative Detoxification of Deoxynivalenol in a Novel Bacterium Ketogulonicigenium vulgare D3_3 Originated from the Feces of Tenebrio molitor Larvae.

Deoxynivalenol (DON) is frequently detected in cereals and cereal-based products and has a negative impact on human and animal health. In this study, an unprecedented DON-degrading bacterial isolate D3_3 was isolated from a sample of Tenebrio molitor larva feces. A 16S rRNA-based phylogenetic analysis and genome-based average nucleotide identity comparison clearly revealed that strain D3_3 belonged to the species Ketogulonicigenium vulgare. This isolate D3_3 could efficiently degrade 50 mg/L of DON under a broad range of conditions, such as pHs of 7.0-9.0 and temperatures of 18-30 °C, as well as during aerobic or anaerobic cultivation. 3-keto-DON was identified as the sole and finished DON metabolite using mass spectrometry. In vitro toxicity tests revealed that 3-keto-DON had lower cytotoxicity to human gastric epithelial cells and higher phytotoxicity to Lemna minor than its parent mycotoxin DON. Additionally, four genes encoding pyrroloquinoline quinone (PQQ)-dependent alcohol dehydrogenases in the genome of isolate D3_3 were identified as being responsible for the DON oxidation reaction. Overall, as a highly potent DON-degrading microbe, a member of the genus Ketogulonicigenium is reported for the first time in this study. The discovery of this DON-degrading isolate D3_3 and its four dehydrogenases will allow microbial strains and enzyme resources to become available for the future development of DON-detoxifying agents for food and animal feed.

Automatic Pretreatment of Dispersive Liquid Liquid Microextraction Based on Immunomagnetic Beads Coupled with UPLC-FLD for the Determination of Zearalenone in Corn Oils.

Sample pretreatment is a vital step in the detection of mycotoxins, and traditional pretreatment methods are time-consuming, labor-intensive and generate much organic waste liquid. In this work, an automatic, high-throughput and environmentally friendly pretreatment method is proposed. Immunomagnetic beads technology and dispersive liquid-liquid microextraction technology are combined, and the zearalenone in corn oils is directly purified and concentrated under the solubilization effects of surfactant. The proposed pretreatment method allows for the batch pretreatment of samples without pre-extraction using organic reagents, and almost no organic waste liquid is produced. Coupled with UPLC-FLD, an effective and accurate quantitative detection method for zearalenone is established. The recovery of spiked zearalenone in corn oils at different concentrations ranges from 85.7 to 89.0%, and the relative standard deviation is below 2.9%. The proposed pretreatment method overcomes the shortcomings of traditional pretreatment methods and has broad application prospects.