Nanometal surface energy transfer-based lateral flow immunoassay for T2 toxin detection.

In this study, we incorporated nanometal surface energy transfer (NSET) in lateral flow immunoassay (LFIA) and explored the relationship between fluorescence quenching efficiency and detection sensitivity to improve sensitivity of NSET-LFIA system. We developed nine gold nanoparticles (GNPs) with absorption spectrum in the range of 520-605 nm as acceptors and quantum dot microspheres (QDMs) with emission spectrum of 530, 570, and 610 nm as donors. By analyzing the overlap integral area, fluorescence quenching efficiency, and detection sensitivity of 27 donor-acceptor pairs, we observed that the larger overlap integral area led to higher fluorescence quenching efficiency and detection sensitivity. A maximum fluorescence quenching efficiency of 91.0% was obtained from the combination of GNPs at 605 nm and QDMs at 610 nm, achieving the highest detection sensitivity. We developed NSET-LFIA for the detection of T2 toxin with a limit of detection of 0.04 ng/mL, which was 10-times higher than that obtained via conventional GNP-LFIA. NSET-LFIA represents a versatile, ultrasensitive and valuable screening tool for small molecules in real samples.

Functional peptide conjugated ordered gold nanoparticles based rational electrochemical immunosensor for highly stable and selective detection of zearalenone.

To integrate antifouling properties and good sensitivity on the sensing interface can improve the applicability of an electrochemical immunosensor. These functional regions can be integrated into a single functional peptide (functPP). The rational designed three domains in functPP were the anchoring, antifouling and gold nanoparticles (AuNPs) recognizing domains. Meanwhile, the ordered AuNPs inspired by C15H23CO-RRRRR can be recognized by AuNPs recognizing domains in functPP to enhance the intensity of detecting current. In the sensing system, the anchoring domain in functPP can be immobilized on the Au electrode by AuS interaction, while the antifouling domain undergoes strong hydration with water molecules to resist matrices, and the recognizing domains can directionally capture O-AuNPs to form a functPP-O-AuNPs complex as the core sensing element. Consequently, the complex bound to the monoclonal antibodies against zearalenone by electrostatic adsorption to develop a highly antifouling and sensitive biosensor with the ability to identify zearalenone in cereals.

An intelligent device with double fluorescent carbon dots based on smartphone for visual and point-of-care testing of Copper(II) in water and food samples.

The excessive presence of Cu2+ could be harmful to human health. Therefore, a ratiometric fluorescence sensor based on multicolor fluorescent carbon dots (CDs) was developed for Cu2+ detection. The blue and yellow carbon dots (B-CDs/Y-CDs) were synthesized by one-step hydrothermal method. After adding Cu2+, it is captured by the amino groups of B-CDs to form complexes, resulting in a strong fluorescence quenching via photoinduced electron transfer (PET). Meanwhile, the amino groups from Y-CDs also binds with Cu2+ that inhibit the internal PET thus enhancing the fluorescence of Y-CDs. The sensor has the merits in rapid, visual, and selective with a low limit of detection (LOD) at 2.29 nM. Furthermore, an intelligent device composed of portable optical detector and smartphone is constructed, which realizes the visual point-of-care testing (POCT) of Cu2+ with a LOD of 7.51 nM. The strategy provides an accessible approach for monitoring heavy metal pollution and food safety.

Pear Wood Pyrolysis Influences Quality and Levels of Polycyclic Aromatic Hydrocarbons in Liquid Smoke.

Limu smoked chicken is a traditional Chinese delicacy; however, polycyclic aromatic hydrocarbons (PAHs) are generated during the smoking process. We developed a pyrolysis process for pear wood liquid smoke with minimal PAH generation. Pear wood liquid smoke products were prepared under different pyrolysis conditions in a self-made pyrolysis reactor, and the total phenol, carbonyl compound, total acid, and PAH contents and PAH toxicity risk were evaluated. With increasing temperatures, the toxicity equivalent ΣPAH of the smoke liquid reached 3.004 µg/kg. With increasing particle sizes, the total phenol content reached 1.6 mg/mL; the phenol content was 5.95 mg/mL. With increasing particle sizes, the toxicity equivalent ΣPAHs of the smoke liquor reached 2.441 µg/kg. The optimal parameters for treating pear wood smoke liquid in the thermal reaction device were a pyrolysis temperature of pear wood of >350 °C, particle size of S2, and sucrose content of 8%.

Discovery and characterization of the PpqI/R quorum sensing system activated by GacS/A and Hfq in Pseudomonas protegens H78.

Pseudomonas protegens can generally produce multiple antibiotics including pyoluteorin (Plt), 2,4-diacetylphloroglucinol (DAPG), and pyrrolnitrin (Prn). In this study, we discovered and characterized a quorum sensing (QS) system, PpqI/R, in P. protegens H78. PpqI/R, encoded by two open reading frames (ORFs) (H78_01960/01961) in P. protegens H78 genome, is a LuxI/R-type QS system. Four long-chain acyl homoserine lactone (AHL) signaling molecules, 3-OH-C10-HSL, 3-OH-C12-HSL, C12-HSL, and 3-OH-C14-HSL, are produced by H78. Biosynthesis of these AHLs is catalyzed by PpqI synthase and activated by the PpqR regulator in H78 and in Escherichia coli when heterologously expressed. PpqR activates ppqI expression by targeting the lux box upstream of the ppqI promoter in cooperation with corresponding AHLs. The four aforementioned AHLs exhibited different capabilities to induce ppqI promoter expression, with 3-OH-C12-HSL showing the highest induction activity. In H78 cells, ppqI/R expression is activated by the two-component system GacS/A and the RNA chaperone Hfq. Differential regulation of the PpqI/R system in secondary metabolism has a negative effect on DAPG biosynthesis and ped operon (involved in volatile organic compound biosynthesis) expression. In contrast, Plt biosynthesis and prn operon expression were positively regulated by PpqI/R. In summary, PpqI/R, the first characterized QS system in P. protegens, is activated by GacS/A and Hfq and controls the expression of secondary metabolites, including antibiotics.

Flaxseed polyphenols: Effects of varieties on its composition and antioxidant capacity.

This study identified phenolic compounds in five flaxseed varieties and evaluated their antioxidant activities. Results showed significant variations in phenolic acids and flavonoids among the varieties. Longya 16 had the lowest flavonoid content, Longya 13 had the lowest phenolic acid content, while Longya 10 exhibited the highest content and diversity of polyphenols, including six flavonoids (vitexin, quercitrin, quercetin, apigenin, kaempfero1, (+)-dihydroquercetin) and five phenolic acids (gallic acid, vanillic acid, ferulic acid, sinapic acid, and 4-hydroxybenzoic acid). Antioxidant activity was assessed using DPPH and ABTS radical scavenging assays, and cell-based assays under tBHP-induced oxidative stress. Flaxseed polyphenol extracts significantly reduced ROS, MDA, and GSSG levels and increased SOD and CAT activities, preserving cell vitality and morphology. These findings confirmed the significant antioxidant activity of flaxseed polyphenols, providing a theoretical basis for their application in antioxidative functional areas.

Implementation and optimization of SpMV algorithm based on SW26010P many-core processor and stored in BCSR format.

The irregular distribution of non-zero elements of large-scale sparse matrix leads to low data access efficiency caused by the unique architecture of the Sunway many-core processor, which brings great challenges to the efficient implementation of sparse matrix-vector multiplication (SpMV) computing by SW26010P many-core processor. To address this problem, a study of SpMV optimization strategies is carried out based on the SW26010P many-core processor. Firstly, we design a memorized data storage transformation strategy to transform the matrix in CSR storage format into BCSR (Block Compressed Sparse Row) storage. Secondly, the dynamic task scheduling method is introduced to the algorithm to realize the load balance between slave cores. Thirdly, the LDM memory is refined and designed, and the slave core dual cache strategy is optimized to further improve the performance. Finally, we selected a large number of representative sparse matrices from the Matrix Market for testing. The results show that the scheme has obviously speedup the processing procedure of sparse matrices with various sizes and sizes, and the master-slave speedup ratio can reach up to 38 times. The optimization method used in this paper has implications for other complex applications of the SW26010P many-core processor.

Changes in physio-biochemical metabolism, phenolics and antioxidant capacity during germination of different wheat varieties.

Changes in physio-biochemical metabolism, phenolics and antioxidant capacity during germination were studied in eight different wheat varieties. Results showed that germination enhanced sprout growth, and caused oxidative damage, but enhanced phenolics accumulation. Ferulic acid and p-coumaric acid were the main phenolic acids in wheat sprouts, and dihydroquercetin, quercetin and vitexin were the main flavonoids. The phenolic acid content of Jimai 44 was the highest on the 2th and 4th day of germination, and that of Bainong 307 was the highest on the 6th day. The flavonoid content of Hei jingang was the highest during whole germination. The enzymes activities of phenylalanine ammonia lyase (PAL), cinnamic acid 4-hydroxylase (C4H) and 4-coumarate coenzyme A ligase (4CL) were up-regulated. The activities of catalase, polyphenol oxidase and peroxidase were also activated. Antioxidant capacity of wheat sprouts was enhanced. The results provided new ideas for the production of naturally sourced phenolic rich foods.

Engineering Escherichia coli for high-yielding 2,5-Dimethylpyrazine synthesis from L-Threonine by reconstructing metabolic pathways and enhancing cofactors regeneration.

2,5-Dimethylpyrazine (2,5-DMP) is important pharmaceutical raw material and food flavoring agent. Recently, engineering microbes to produce 2,5-DMP has become an attractive alternative to chemical synthesis approach. In this study, metabolic engineering strategies were used to optimize the modified Escherichia coli BL21 (DE3) strain for efficient synthesis of 2,5-DMP using L-threonine dehydrogenase (EcTDH) from Escherichia coli BL21, NADH oxidase (EhNOX) from Enterococcus hirae, aminoacetone oxidase (ScAAO) from Streptococcus cristatus and L-threonine transporter protein (EcSstT) from Escherichia coli BL21, respectively. We further optimized the reaction conditions for synthesizing 2,5-DMP. In optimized conditions, the modified strain can convert L-threonine to obtain 2,5-DMP with a yield of 2897.30 mg/L. Therefore, the strategies used in this study contribute to the development of high-level cell factories for 2,5-DMP.

The Pea Oligosaccharides Could Stimulate the In Vitro Proliferation of Beneficial Bacteria and Enhance Anti-Inflammatory Effects via the NF-κB Pathway.

The oligosaccharides extracted from the seeds of peas, specifically consisting of raffinose, stachyose, and verbascose, fall under the category of raffinose family oligosaccharides (RFOs). The effect of RFOs on intestinal microflora and the anti-inflammatory mechanism were investigated by in vitro fermentation and cell experiments. Firstly, mouse feces were fermented in vitro and different doses of RFOs (0~2%) were added to determine the changes in the representative bacterial community, PH, and short-chain fatty acids in the fermentation solution during the fermentation period. The probiotic index was used to evaluate the probiotic proliferation effect of RFOs and the optimal group was selected for 16S rRNA assay with blank group. Then, the effects of RFOs on the inflammatory response of macrophage RAW264.7 induced by LPS were studied. The activity of cells, the levels of NO, ROS, inflammatory factors, and the expression of NF-κB, p65, and iNOS proteins in related pathways were measured. The results demonstrated that RFOs exerted a stimulatory effect on the proliferation of beneficial bacteria while concurrently inhibiting the growth of harmful bacteria. Moreover, RFOs significantly enhanced the diversity of intestinal flora and reduced the ratio of Firmicutes-to-Bacteroides (F/B). Importantly, it was observed that RFOs effectively suppressed NO and ROS levels, as well as inflammatory cytokine release and expression of NF-κB, p65, and iNOS proteins. These findings highlight the potential of RFOs in promoting intestinal health and ameliorating intestinal inflammation.

A NILM load identification method based on structured V-I mapping.

With the increasing number and types of global power loads and the development and popularization of smart grid technology, a large number of researches on load-level non-intrusive load monitoring technology have emerged. However, the unique power characteristics of the load make NILM face the difficult problem of low robustness of feature extraction and low accuracy of classification and identification in the recognition stage. This paper proposes a structured V-I mapping method to address the inherent limitations of traditional V-I trajectory mapping methods from a new perspective. In addition, for the verification of the V-I trajectory mapping method proposed in this paper, the complexity of load characteristics is comprehensively considered, and a lightweight convolutional neural network is designed based on AlexNet. The experimental results on the NILM dataset show that the proposed method significantly improves recognition accuracy compared to existing VI trajectory mapping methods.

The Impact of High Temperature on Microbial Communities in Pork and Duck Skin.

Pork skin and duck skin are highly favored by consumers in China, and high-temperature processing methods are widely employed in cooking and food preparation. However, the influence of high-temperature treatment on the microbial communities within pork skin and duck skin remains unclear. In this study, a high-temperature treatment method simulating the cooking process was utilized to treat samples of pork skin and duck skin at temperatures ranging from 60 °C to 120 °C. The findings revealed that high-temperature treatment significantly altered the microbial communities in both pork skin and duck skin. Heat exposure resulted in a decrease in microbial diversity and induced changes in the relative abundance of specific microbial groups. In pork skin, high-temperature treatment led to a reduction in bacterial diversity and a decline in the relative abundance of specific bacterial taxa. Similarly, the relative abundance of microbial communities in duck skin also decreased. Furthermore, potential pathogenic bacteria, including Gram-positive and Gram-negative bacteria, as well as aerobic, anaerobic, and facultative anaerobic bacteria, exhibited different responses to high-temperature treatment in pork skin and duck skin. These findings highlighted the substantial impact of high-temperature processing on the composition and structure of microbial communities in pork skin and duck skin, potentially influencing food safety and quality. This study contributed to an enhanced understanding of the microbial mechanisms underlying the alterations in microbial communities during high-temperature processing of pork skin and duck skin, with significant implications for ensuring food safety and developing effective cooking techniques.

Production of monoclonal antibody against tylosin and tilmicosin with homogeneous cross-reactivity and its application in lateral flow immunoassay.

To avoid false negative results due to the low cross-reactivity rate (CR) in rapid immunoassay, a group-specific antibody with homogeneous CR toward target compounds is needed for accuracy. In this study, tylosin (TYL) and tilmicosin (TM) were selected as model molecules. Firstly, two-dimensional similarity, electrostatic potential energy, spatial conformation and charge distribution of the haptens TYL-CMO, TYL-6-ACA, TYL-4-APA, TYL-CHO and DES-CMO and target compounds of TYL and TM were obtained using Gaussian 09W and Discovery Studio. The optimal hapten was DES-CMO because it is the most similar to TYL and TM. Subsequently, the mAb 14D5 cell line was obtained with IC50 values of 1.59 and 1.72 ng/mL for TYL and TM, respectively, and a CR of 92.44%. Finally, amorphous carbon nanoparticles (ACNPs) were conjugated with mAb 14D5 to develop an accurate lateral flow immunoassay (LFA) for detection of TYL and TM by the reflectance value under natural light. The recoveries of TYL and TM ranged from 77.18 to 112.04% with coefficient of variation < 13.43%. The cut-off value in milk samples was 8 ng/mL, and the limits of detection were 11.44, 15.96, 22.29 and 25.53 µg/kg for chicken muscle, bovine muscle, porcine muscle and porcine liver samples, respectively, and the results being consistent with HPLC-UV. The results suggest that the developed LFA is accurate and potentially useful for on-site screening of TYL and TM in milk and animal tissue samples.

Effect of 2'-Fucosyllactose on Beige Adipocyte Formation in 3T3-L1 Adipocytes and C3H10T1/2 Cells.

2'-Fucosyllactose (2'-FL), the functional oligosaccharide naturally present in milk, has been shown to exert health benefits. This study was aimed to investigate the effect of 2'-fucosyllactose (2'-FL) on the browning of white adipose tissue in 3T3-L1 adipocytes and C3H10T1/2 cells. The results revealed that 2'-FL decreased lipid accumulations with reduced intracellular triglyceride contents in vitro. 2'-FL intervention increased the mitochondria density and the proportion of UCP1-positive cells. The mRNA expressions of the mitochondrial biogenesis-related and browning markers (Cox7a, Cyto C, Tfam, Ucp1, Pgc1α, Prdm16, Cidea, Elovl3, Pparα, CD137, and Tmem26) were increased after 2'-FL intervention to some extent. Similarly, the protein expression of the browning markers, including UCP1, PGC1α, and PRDM16, was up-regulated in the 2'-FL group. Additionally, an adenosine monophosphate-activated protein kinase (AMPK) inhibitor, compound C (1 µM), significantly decreased the induction of thermogenic proteins expressions mediated by 2'-FL, indicating that the 2'-FL-enhanced beige cell formation was partially dependent on the AMPK pathway. In conclusion, 2'-FL effectively promoted the browning of white adipose in vitro.

Development of a monoclonal antibody-based lateral flow immunoassay for the detection of benzoic acid in liquid food.

To monitor benzoic acid (BA) residues in liquid food samples, a monoclonal antibody (mAb)-based lateral flow immunoassay (LFA) was developed in this study. First, 2-aminobenzoic acid (2-AA), 3-aminobenzoic acid (3-AA), and 4-aminobenzoic acid (4-AA) were conjugated to BSA and used as immunogens. After cell fusion, mAb 6D8 from 4-AA-BSA performed best with an IC50 value of 0.21 mg L-1 using 3-AA-OVA as a heterogeneous antigen, which represented a 3.4-fold improvement compared with the homogeneous antigen 4-AA-BSA. Subsequently, eight kinds of CGNPs with sizes varying from 20.94 nm to 90.00 nm were synthesized for screening the suitable size to develop a sensitive LFA. Finally, a sensitive LFA based on colloidal gold (23.27 nm) nanoparticles was developed for screening BA with a cut-off value of 4 mg L-1, which could meet the requirement of BA detection in milk, Fanta, Sprite, Coca-Cola, and Smart samples.

Improving the quality of soluble dietary fiber from Poria cocos peel residue following steam explosion.

Poria cocos peel residue (PCPR) still contains much soluble dietary fiber (SDF), steam explosion (SE) treatment was applied to PCPR to create a superior SDF. Steam pressure of 1.2 MPa, residence period of 120 s, and moisture content of 13% were the optimized parameters for SE treatment of PCPR. Under optimized circumstances, SE treatment of PCPR enhanced its SDF yield from 5.24% to 23.86%. Compared to the original SDF, the SE-treated SDF displayed improved enzyme inhibition, including the inhibition of α-amylase and pancreatic lipase, also enhanced water holding, oil holding, water swelling, nutrient adsorption including cholesterol, nitrite ions, and glucose and antioxidant abilities. Additionally, it had a decreased molecular weight, improved thermal stability, and a rough surface with many pores of different sizes. Given that SDF had been improved physiochemical and functional characteristics thanks to SE treatment, it might be the excellent functional ingredient for the food business.

Merge Loss Calculation Method for Highly Imbalanced Data Multiclass Classification.

In real classification scenarios, the number distribution of modeling samples is usually out of proportion. Most of the existing classification methods still face challenges in comprehensive model performance for imbalanced data. In this article, a novel theoretical framework is proposed that establishes a proportion coefficient independent of the number distribution of modeling samples and a general merge loss calculation method independent of class distribution. The loss calculation method of the imbalanced problem focuses on both the global and batch sample levels. Specifically, the loss function calculation introduces the true-positive rate (TPR) and the false-positive rate (FPR) to ensure the independence and balance of loss calculation for each class. Based on this, global and local loss weight coefficients are generated from the entire dataset and batch dataset for the multiclass classification problem, and a merge weight loss function is calculated after unifying the weight coefficient scale. Furthermore, the designed loss function is applied to different neural network models and datasets. The method shows better performance on imbalanced datasets than state-of-the-art methods.

GABA Application Enhances Drought Stress Tolerance in Wheat Seedlings (Triticum aestivum L.).

In this study, the effects of γ-aminobutyric acid (GABA) on physio-biochemical metabolism, phenolic acid accumulation, and antioxidant system enhancement in germinated wheat under drought stress was investigated. The results showed that exogenous GABA reduced the oxidative damage in wheat seedlings caused by drought stress and enhanced the content of phenolics, with 1.0 mM being the most effective concentration. Six phenolic acids were detected in bound form, including p-hydroxybenzoic acid, vanillic acid, syringic acid, p-coumaric acid, ferulic acid, and sinapic acid. However, only syringic acid and p-coumaric acid were found in free form. A total of 1.0 mM of GABA enhanced the content of total phenolic acids by 28% and 22%, respectively, compared with that of drought stress, on day four and day six of germination. The activities of phenylalanine ammonia lyase (PAL), cinnamic acid 4-hydroxylase (C4H) and 4-coumarate coenzyme A ligase (4CL) were activated by drought stress plus GABA treatment. Antioxidant enzyme activities were also induced. These results indicate that GABA treatment may be an effective way to relieve drought stress as it activates the antioxidant system of plants by inducing the accumulation of phenolics and the increase in antioxidant enzyme activity.

Development of a Lateral Flow Immunoassay Based on a Highly Specific Monoclonal Antibody To Detect 4-Methylaminoantipyrine.

To avoid false-positive results in immunoassays due to cross-reactivity of antibodies with structural analogues, especially metabolites of target compounds, the preparation of highly specific antibodies is crucial. Preserving the characteristic structure of a target compound when designing a hapten is important when preparing highly specific antibodies. Here, we designed a novel hapten, 4-(((1,5-dimethyl-3-oxo-2-phenyl-2,3-dihydro-1H-pyrazol-4yl)amino)methyl)benzoic acid, named AA-BA, to improve the specificity of antibodies for detection of 4-methylaminoantipyrine (MAA), a residual marker of dipyrone, an important antipyretic-analgesic and anti-inflammatory drug. The structural features of the hapten remained almost the same as those of MAA. After experimental validation, monoclonal antibody 6A4 (mAb 6A4) was prepared with the half maximal inhibitory concentration (IC50) value of 4.03 ng/mL and negligible cross-reactivity with dipyrone metabolites and other antibiotics. In addition, a specific lateral flow immunoassay (LFA) strip based on colloidal gold was developed for screening MAA with a cutoff value of 25 ng/mL in milk. The developed LFA is a useful tool for rapid and accurate detection of MAA.

A self-assembled DNA double-crossover-based fluorescent aptasensor for highly sensitivity and selectivity in the simultaneous detection of aflatoxin M1 and aflatoxin B1.

Realizing the simultaneous speedy detection of multiple mycotoxins in contaminated food and feed is of great practical importance in the domain of food manufacturing and security. Herein, a fluorescent aptamer sensor based on self-assembled DNA double-crossover was developed and used for effective simultaneous quantitative detection of aflatoxins M1 and B1 by fluorescence resonance energy transfer (FRET). Fluorescent dye-modified aflatoxin M1 and B1 aptamers are selected as recognition elements and signal probes, and DNA double crosses are consistently locked by the aflatoxin aptamers, which results in a "turn-off" of the fluorescent signal. In the presence of AFM1 and AFB1, the aptamer sequences are more inclined to form Apt-AFM1 and Apt-AFB1 complexes, and the fluorescent probes are released from the DNA double-crossing platform, leading to an enhanced fluorescent signal (Cy3: 568 nm; Cy5: 660 nm). Under the optimal conditions, the signal response of the constructed fluorescent aptamer sensor showed good linearity with the logarithm of AFM1 and AFB1 concentrations, with detection limits of 6.24 pg/mL and 9.0 pg/mL, and a wide linear range of 0.01-200 ng/mL and 0.01-150 ng/mL, respectively. In addition, the effect of potential interfering substances in real samples was analyzed, and the aptasensor presented a good interference immunity. Moreover, by modifying and designing aptamer probes, the sensor can be applied to high-throughput simultaneous screening of other analytes, providing a new approach for the development of fluorescent aptamer sensors.