Rapid detection of Escherichia coli O157:H7 by a fluorescent microsphere-based immunochromatographic assay and immunomagnetic separation.

To ensure food safety and avoid infections by Escherichia coli O157:H7 (E. coli O157:H7), we developed a novel fluorescent microsphere (FM)-based immunochromatography assay (FM-ICA). FMs were conjugated to anti-E. coli O157:H7 monoclonal antibody (MAb) as an ICA probe, Immunomagnetic beads (IM-beads) were prepared by conjugating functionalized magnetic microspheres with the antibody for enrichment and separation of pathogenic bacteria from complex food matrices. Under selected conditions, a standard curve of FM-ICA measurement of E. coli O157:H7 was developed with a linear range from 3 × 105 to 6 × 107 colony-forming units (CFU)/mL in PBS buffer. The recoveries of intra- and inter assay ranged from 101.64% to 107.03% and 95.62%-110.2% respectively, with CV below 10%. The FM-ICA showed good sensitivity, accuracy and precision. When IM-beads separation plus FM-ICA (IMS-FICA) were used to assay raw food samples, sensitivity was 3 × 103 CFU/mL, a 33-fold improvement compared with FM-ICA only. Moreover, this method had high specificity for E. coli O157:H7 and can be used to assay E. coli O157:H7 in beef, milk and water samples. This assay can be completed within 2 h and has great potential for on-site quantitation of E. coli O157:H7 with simplicity, rapidity, sensitivity, and cost-effectiveness.

Development of anti-Müllerian hormone immunoassay based on biolayer interferometry technology.

Anti-Müllerian hormone (AMH) is a biomarker for the assessment of female fertility. The accurate measurement of the concentration of AMH is relevant for the success of assisted reproductive therapies and diagnosis of clinical cases. In this study, we show that cytokines such as fetal liver tyrosine kinase 3 ligand (Flt3L), CC subtype chemokine ligand 20 (CCL20), granulocyte-macrophage colony-stimulating factor (GM-CSF), and ß2-microglobulin (ß2M) significantly enhance the immune response against AMH. Two anti-AMH monoclonal antibodies (mAbs) with high affinity were selected by biolayer interferometry (BLI) technology for application in a fully automated magnetic chemiluminescence immunoassay (CLIA). This robust and rapid assay can efficiently detect AMH in the range of 0.125~20 ng mL-1 with a detection limit of 0.099 ng mL-1. This immunoassay showed high specificity with no cross-reaction with structurally related proteins and some of the other members of the TGF-ß super family, such as inhibin A, activin A, follicle-stimulating hormone, and luteinizing hormone. The average recovery rates of three different batches were 100.19%, 102.72%, and 103.59%, respectively, with coefficients of variation of less than 12%. The developed assay was applied in the detection of AMH in 69 serum samples from randomly selected patients. Our data showed a high correlation with those obtained using commercially available ELISA kits (correlation coefficient, 0.9831). Hence, we suggest that this immunoassay could find application in the development of POCT for the diagnosis of AMH in clinical samples. Graphical abstract.

Development of a lateral flow immunoassay of C-reactive protein detection based on red fluorescent nanoparticles.

We have developed a reliable and rapid immunoassay based on a facile synthesis of fluorescent nanoparticles integrated in immunochromatography technique to quantitatively detect C-reactive protein (CRP). The method is based on a sandwich immunoassay using the Nile-red doped nanoparticles/CRP monoclonal antibody conjugate. The method is simple and fast, with a detection limit of 0.091 mg/L. It provides quantitative analysis in the range of 0.1-160 mg/L, which is adequate for detecting CRP of acute inflammatory or cardiovascular disease. This strategy displayed a good reproducibility and stability to straightforwardly analyze the plasma samples without complicated washing steps, thereby reducing the operating procedures for non-professionals and promoting the detection efficiency and the whole detection process can be completed in 3 min. This approach for carrying out immunoassays can be applied to the detection of CRP in the point-of-care tests.

Rapid and Sensitive Detection of Cardiac Troponin I for Point-of-Care Tests Based on Red Fluorescent Microspheres.

A reliable lateral flow immunoassay (LFIA) based on a facile one-step synthesis of single microspheres in combining with immunochromatography technique was developed to establish a new point-of-care test (POCT) for the rapid and early detection of cardiac troponin I (cTnI), a kind of cardiac specific biomarker for acute myocardial infarction (AMI). The double layered microspheres with clear core-shell structures were produced using soap-free emulsion polymerization method with inexpensive compounds (styrene and acrylic acid). The synthetic process was simple, rapid and easy to control due to one-step synthesis without any complicated procedures. The microspheres are nanostructure with high surface area, which have numerous carboxyl groups on the out layer, resulting in high-efficiency coupling between the carrier and antibody via amide bond. Meanwhile, the red fluorescent dye, Nile-red (NR), was wrapped inside the microspheres to improve its stability, as well to reduce the background noise, because of its higher emission wavelength than interference from real plasma samples. The core-shell structures provided different functional areas to separate antibody and dyes, so the immunoassay has highly sensitive, wide working curves in the range of 0⁻40 ng/mL, low limits of detection (LOD) at 0.016 ng/mL, and limits of quantification (LOQ) at 0.087 ng/mL with coefficient of variations (CV) of 10%. This strategy suggested an outstanding platform for LFIA, with good reproducibility and stability to straightforwardly analyze the plasma samples without washing steps, thereby reducing the operating procedures for non-professionals and promoting detection efficiency. The whole detection process can be completed in less than 15 min. This novel immunoassay offers a reliable and favorable analytical result by detecting the real samples, indicating that it holds great potential as a new alternative for biomolecule detection in complex samples, for the early detection of cardiac specific biomarkers.

Increased Expression of Thioredoxin-1 Binding Protein-2 in Placentas in Preeclampsia.

OBJECTIVE: To examine the expressions of thioredoxin-1 (TRX-1) and thioredoxin-1 binding protein-2 (TBP-2) in placentas affected by preeclampsia. STUDY DESIGN: We examined the mRNA levels of TRX-1, TBP-2, cyclooxygenase-2 (COX-2), and tumor necrosis factor-α (TNF-α) in preeclamptic (n=20) and normal placentas (n=18) by quantitative reverse transcriptase-polymerase chain reaction. RESULTS: We found the mRNA level of TRX-1 was significantly decreased (p<0.005), while the mRNA levels of TBP-2, COX-2, and TNF-α were significantly increased in the placentas in preeclampsia when compared to the normal group (p<0.005). CONCLUSION: These data suggest that TBP-2 may play roles in the pathophysiology of preeclampsia, probably by contributing to oxidative stress and inflammation. Thus, TBP-2 may be a potential therapeutic target for preeclampsia.

Curcumin Nanocapsules based on carbon dots for photodynamic sterilization towards Listeria monocytogenes and Staphylococcus aureus.

Curcumin (Cur) as a natural food additive and photosensitizer has been widely applied on photodynamic sterilization and preservation for food, but the poor aqueous solubility and light stability restrict its extensive application. In this study, we report a Cur nanocapsules (Cur-CDs) made by carbon dots (CDs). Attributing to the hydrogen bonds formed between Cur and CDs, Cur-CDs exhibits excellent Cur aqueous solubility each to 9286.98 ng/mL (enhanced by 246.27 times) and light stability (enhanced by 1.51 times). The photogenerated electron transmission from Cur to CDs in addition resulted in >1.23 and 1.60 times generation of •O2- and •OH, compared to that of bare Cur. Accordingly, 5.73 × 103 CFU L. monocytogenes, and 5.43 × 103 CFU S. aureus were killed by 0.06 mg/mL Cur-CDs within 20 mins of blue light, showing the promising potential in the development and application of safe and environmentally friendly non-thermal sterilization technology based on Cur-CDs.

Waste to Wealth: Dynamics and metabolic profiles of the conversion of jackfruit flake into value-added products by different fermentation methods.

Thus far, little is known about whether jackfruit flake, a byproduct of jackfruit, can be used as a fermentation substrate to obtain value-added products through microbial fermentation. Here, jackfruit flake puree was fermented by three different ways: spontaneous fermentation (JF), inoculated with LAB (JFL), inoculated co-fermentation with LAB and yeast (JFC). In contrast to JF, the total polyphenol and flavonoid content and syndrome-associated enzyme inhibition are significantly increased in JFC at the end of fermentation. Electronic tongue analysis revealed that the JFC was significantly lower in astringency and higher in bitterness. 41 volatile compounds were identified during fermentation by HS-SPME-GC-MS, and JFC was richer in honey, rose, and fruity flavors. A total of 290 compounds were screened for discriminative pre- and post-fermentation differential metabolites by non-target metabolomics analysis. These results provide a potential reference for the conversion of jackfruit waste into functional products using fermentation.

Investigating the Impact of Pineapple-Whey Protein Fermentation Products on Cefixime-Induced Intestinal Flora Dysbiosis in Mice Using 16S Sequencing and Untargeted Metabolomics Techniques.

In our previous study, a new fermented food (PWF) created by utilizing pineapple by-products and whey proteins as a matrix via co-fermentation with lactic acid bacteria and yeast was developed, and, in the current study, we examined the impact of a pineapple-whey protein fermentation product on a cefixime-induced dysbiosis model in mice using 16S sequencing and untargeted metabolomics techniques. The results indicated that the pineapple-whey protein fermentation product played a positive role in restoring the intestinal flora. In this study, cefixime reduced the overall abundance of intestinal flora and decreased the relative abundance of probiotics in the gut, while also inhibiting amino acid metabolism. The addition of PWF normalized the intestinal flora to a steady state, significantly increasing the populations of Weissella, Lactococcus, Faecalibaculum, and Bacteroides acidophilus, while decreasing the numbers of Akkermansia and Escherichia-Shigella. Additionally, PWF modulated microbial metabolites, such as L-glutamate and L-threonine, and upregulated amino-acid-related metabolic pathways, including those involving glycine, serine, and threonine. In conclusion, PWF can alleviate intestinal flora dysbiosis and metabolic disturbances induced by antibiotic interventions. It is suggested that PWF could be a potential dietary strategy for patients with antibiotic-associated diarrhea.

Dynamics of nutrients, sensory quality and microbial communities and their interactions during co-fermentation of pineapple by-products and whey protein.

In this study, a new fermented food was developed using pineapple by-products and whey protein (2.6%) as raw materials through the co-fermentation of autochthonous lactic acid bacteria and yeast. To better understand the fermentation mechanism and the impact of microorganisms on the entire fermentation system, we tracked the changes in carbohydrate and amino acid profiles, organoleptic quality and microbial community during the fermentation process. Compared with unfermented samples, dietary fiber and free amino acids increased significantly as fermentation proceeded. The fermented samples were significantly lower in astringency and bitterness and significantly higher in sourness, umami and richness. The fermented products were richer in volatile compounds with floral, cheesy, fruity and other flavors. Relevant analyses showed that the core microbial community was highly correlated with the quality attributes of the fermented products. Microorganisms such as Lactococcus, Weissella, Hanseniaspora, Saccharomyces and Lachancea contributed significantly to the fermented products.

Fractional extraction of lignin from coffee beans with low cytotoxicity, excellent anticancer and antioxidant activities.

Lignin, a biopolymer generated from renewable resources, is widely present in terrestrial plants and possesses notable biosafety characteristics. The objective of this work was to assess the edible safety, in vitro antioxidant, and anti-cancer properties of various lignin fractions isolated from commercially available coffee beans often used for coffee preparation. The findings suggest that the phenolic hydroxyl content increased from 3.26 mmol/g (ED70L) to 5.81 mmol/g (ED0L) with decreasing molecular weight, which resulted in more significant antioxidant properties of the low molecular weight lignin fraction. The findings of the study indicate that the viability of RAW 264.7 and HaCaT cells decreased as the quantity of lignin fractions increased. It was observed that concentrations below 200 µg/mL did not exhibit any harmful effects on normal cells. The results of the study demonstrated a significant reduction of cancer cell growth (specifically A375 cells) at a concentration of 800 µg/mL for all lignin fractions, with an observed inhibition rate of 95 %. The results of this study indicate that the lignin extracts derived from coffee beans exhibit significant potential in mitigating diseases resulting from excessive radical production. Furthermore, these extracts show promise as natural antioxidants and anti-cancer agents.

The interaction study of soluble pectin fiber and surimi protein network from silver carp (Hypophthalmichthys molitrix) based on a new prediction model.

Pure surimi of silver carp (Hypophthalmichthys molitrix) cannot meet the texture requirements in novel 3D printing of food. In this work, the effect mechanism of adding soluble pectin fiber on the quality of surimi was studied at molecular scale, and the interaction has been discussed by a novel prediction model. In comparison with pure surimi, pH and water-holding capacity decreased with increasing pectin, and texture properties improved. The storage modulus firstly rose and then decreased, reaching a maximum value of 15012 Pa at 0.5 % pectin addition. The thermal transition temperature of myosin was moved from 52.13 to 49.80 °C. Pectin extended the T22 relaxation time, suggesting a decrease in immobilized water. A new Time-series prediction model and interaction analysis further explored the intrinsic correlation of various parameters of surimi with different pectin additions. This work contributes to add our understanding of pectin application in surimi products in future special dietary food.

Transepithelial transport and cytoprotection of novel antioxidant peptides isolated from simulated gastrointestinal digestion of Xuanwei ham.

As a traditional fermented meat product, dry-cured Xuanwei ham could be a rich source of bioactive peptides. This study intended to investigate the transepithelial transport and cytoprotection of antioxidant peptides isolated from simulated gastrointestinal digestion of Xuanwei ham. Through ultrafiltration and gel filtration chromatography after simulated digestion, five new antioxidative cell-penetrating peptides (CPPs) with 16-27 amino acid residues were identified, and protective effects of the pretreatment with GHYTEGAELVDSVLDVVRK (GK-19) and TDEFQLHTNVNDGTEFGGSIYQK (TK-23) on H2O2-induced damaged HepG2 cells were investigated. The results showed that the peptide TK-23 at 0.5 mg mL-1 showed a good antioxidant activity through upregulating the activity of antioxidant enzymes (CAT, SOD and GR) and decreasing the MDA level in H2O2-induced damaged HepG2 cells with a better protective effect compared to GSH. Our observations of novel antioxidant CPPs with 16-27 amino acid residues could enrich the antioxidative CPP database, and these findings could provide data support for further study of CPPs.

Comparative study of the effects of ultrasound-assisted alkaline extraction on black soldier fly (Hermetia illucens) larvae protein: Nutritional, structural, and functional properties.

In this study, we developed an ultrasound-assisted alkaline method for extracting black soldier fly larvae protein (BSFLP). The effects of ultrasound-assisted extraction on the nutritional value, structural characteristics, and techno-functional properties of BSFLP were compared with those using the conventional hot alkali method. The results showed that ultrasound-assisted extraction significantly increased the extraction ratio of BSFLP from 55.40% to 80.37%, but reduced the purity from 84.19% to 80.75%. The BSFLP extracted by ultrasound-assisted extraction met the amino acid requirements for humans proposed by the Food and Agriculture Organization in 2013, and ultrasound-assisted extraction did not alter the limiting amino acids of the BSFLP. The ultrasound-assisted extraction increased the in vitro protein digestibility from 82.97% to 99.79%. Moreover, ultrasound-assisted extraction obtained BSFLP with a more ordered secondary structure and more loosely porous surface morphology, without breaking the peptide bonds. By contrast, the conventional hot alkaline method hydrolyzed BSFLP into smaller fragments. The effect of ultrasound-assisted extraction on the structure of BSFLP improved the solubility and emulsion capacity of BSFLP, but reduced its foaming properties. In conclusion, the results of this study suggest that ultrasound-assisted alkaline extraction could be a suitable method for extracting BSFLP and improving its nutritional value, and structural and functional properties. The findings obtained in this study could promote the wider application of BSFLP in food industry.

Artificial Intelligence Assistive Technology in Hospital Professional Nursing Technology.

Global aging is becoming more and more serious, and the nursing problems of the elderly will become very serious in the future. The article designs a control system with ATmega128 as the main controller based on the function of the multifunctional nursing robot. The article uses a convolutional neural network structure to estimate the position of 3D human joints. The article maps the joint coordinates of the colour map to the depth map based on the two camera parameters. At the same time, 15 joint heat maps are constructed with the joint depth map coordinates as the centre, and the joint heat map and the depth map are bound to the second-level neural network. The prediction of the position of the user's armpit is further completed by image processing technology. We compare this method with other attitude prediction methods to verify the advantages of this research method. The research background of this article is carried out in the context of global aging in the 21st century.

A new functionality study of vanillin as the inhibitor for α-glucosidase and its inhibition kinetic mechanism.

Vanillin is a natural phenolic compound mainly used as flavors in food industry. In this work, a new functionality of vanillin as the α-glucosidase inhibitor was studied based on the inhibition kinetic mechanism. The inhibitory effect (IC50) of vanillin against α-glucosidase was 28.34 ± 0.89 mg/mL, which belongs to mixed inhibition mechanism and its process was spontaneous. Vanillin could bind to α-glucosidase by hydrophobic interactions and hydrogen bonds with -8.42 kcal/mol intermolecular energy to form the steric hindrance. The average binding distances was calculated as 2.20 nm according to energy transfer theory. In addition, the protein secondary structure and denaturation temperature (decreasing about 10 °C) were changed significantly after vanillin binding to α-glucosidase, resulting in an inhibitory effect. The findings of this research provide insights for the development of vanillin as potential inhibitor for α-glucosidase in special dietary foods.

An integration study of microalgae bioactive retention: From microalgae biomass to microalgae bioactives nanoparticle.

Microalgae metabolites include biologically active compounds with therapeutic effects such as anticancer, anti-inflammatory and immunomodulation effects. One of the most recent focuses is on utilizing microalgae lipid-based biologically active compounds in food applications. However, most microalgae biological active compounds in their natural forms have common drawbacks like low solubility, low physicochemical stability and strong susceptibility to degradation, which significantly limits their application in foods, therefore, it is important to find solutions to retain their functional properties. In the present work, a comprehensive review on multi-product biorefinery was carried out from upstream processing stage to downstream processing stage, and identify critical processes and factors that impact bioactive material acquisition and retention. Furthermore, since nanoencapsulation technology emerges as an effective solution for microalgae nutraceutical product's retention, this work also focus on the nanoparticle perspective and comprehensively reviews the current nanoencapsulation solutions of the microalgae bioactive extract products. The aim is to depict advances in the formulations of microalage bioactive nanoparticles and provide a critical analysis of the reported nanoparticle formation. Overall, through the investigation of microalgae from biomass to bioactive nanoparticles, we aim to facilitate microalgae nutraceuticals incorporation as high value-added ingredients in more functional food that can improve human health.

A sensitive and rapid chemiluminescence immunoassay for point-of-care testing (POCT) of copeptin in serum based on high-affinity monoclonal antibodies via cytokine-assisted immunization.

Purpose: Antibodies are key reagents in the development of immunoassay. We attempted to develop high-performance CPP immunoassays using high-affinity monoclonal antibodies prepared via cytokine-assisted immunization. Methods: We used fetal liver tyrosine kinase 3 ligand (Flt3L), CC subtype chemokine ligand 20 (CCL20), and granulocyte-macrophage colony-stimulating factor (GM-CSF) to assist traditional subcutaneous immunization of preparing high-affinity monoclonal antibodies, and further to develop high-performance immunoassay methods for CPP. Results: This novel immune strategy significantly enhanced immune response against CPP. Six anti-CPP monoclonal antibodies (mAbs) with high affinity were successfully screened and selected for application in a fully automated magnetic chemiluminescence immunoassay (CLIA). This robust and rapid assay can efficiently detect CPP in the range of 1.2-1250 pmol L-1 with a detection limit of 6.25 pmol L-1. Significantly, the whole incubation process can be completed in 30 min as compared to about 4.5 hr for the control ELISA kit. Furthermore, this assay exhibited high sensitivity and specificity, low intra-assay and inter-assay coefficients of variation (CVs < 15%). The developed assay was applied in the detection of CPP in 115 random serum samples and results showed a high correlation with data obtained using a commercially available ELISA kit (correlation coefficient, 0.9737). Conclusion: Our assay could be applied in the point-of-care testing of CPP in the serum samples, and also the method developed in this study could be adopted to explore the detection and diagnosis of other biomarkers for various diseases.

Adsorption of catechin onto cellulose and its mechanism study: Kinetic models, characterization and molecular simulation.

Catechin, an important component of flavan-3-ol, and dietary fiber are both important ingredients with many associated health benefits. The adsorption of catechin onto various dietary fiber has been studied widely, most of the researches focus on the adsorption capacities of catechin under different fibers and the adsorption types by using adsorption models. However, little is known on the dynamic adsorption process and mechanism, including the adsorption sites, interaction types, and participant molecules. In this study, the adsorption behavior and mechanism of catechin onto cellulose were examined by the time function in combination with molecular simulation. The adsorption capacities of cellulose for catechin were 2.70 and 2.82 mg/g at pH 2.0 and 7.0, respectively. The adsorption process was fitted by three stage models (rapid adsorption, saturation, and equilibrium). The features of cellulose and catechin were characterized by FTIR to identify the functional groups in the adsorption. Molecular simulation revealed that the catechin was adsorbed onto the hydrophilic surface of cellulose rather than hydrophobic one, and that the total binding energy was -8.57 kcal/mol of the hydrophilic surface, which was due to Van der Waals' force and H-bond more than electrostatic force. Furthermore, the studies on isothermal adsorption combined with adsorption at various pH illustrated the main interaction between cellulose and catechin for the binding. This work assisted understanding of the adsorption of polyphenols on to insoluble dietary fiber and has the potential of applications in functional foods.

Ovalbumin as a carrier to significantly enhance the aqueous solubility and photostability of curcumin: Interaction and binding mechanism study.

Egg ovalbumin (OVA) as a macromolecular carrier has the potential to improve the solubility and stability of insolubility bioactive molecules, however, their binding behavior and the mechanism is still ambiguous. In this work, the curcumin was selected as the target to study the interaction and binding mechanism between curcumin and OVA by thermodynamic titration technique in combination with molecular dynamic simulation. The results suggested that the binding included two steps: first, curcumin molecule entered into the hydrophobic pocket of OVA by hydrophobic interaction; and second the interaction was enhanced via hydrogen bonds, resulting in static fluorescence quenching and secondary structural change of OVA. This study provided further evidence in support of the proposed mechanism of the polyphenol-protein binding by the "Hands-gloves" model. Furthermore, when the OVA was as a carrier, the solubility of curcumin has been increased ~370 times to 32.73 µg/mL compared to that of free curcumin at pH 7.0. The photostability was enhanced significantly indicating that it is an efficient way to improve the stability of curcumin in contributing to its application in nutritional supplements or functional foods.

Nicotine suppresses the neurotoxicity by MPP+/MPTP through activating α7nAChR/PI3K/Trx-1 and suppressing ER stress.

Parkinson's disease (PD) is a neurodegenerative disease. Nicotine has been reported to have the role in preventing Parkinson's disease. However, its mechanism is still unclear. In present study we found that nicotine suppressed 1-methyl-4-phenylpyridinium ion(MPP+) toxicity in PC12 cells by MTT assay. The expression of thioredoxin-1(Trx-1) was decreased by MPP+, which was restored by nicotine. The nicotine suppressed expressions of Glucose-regulated protein 78(GRP78/Bip) and C/EBP homologous protein (CHOP) induced by MPP+. The methyllycaconitine (MLA), the inhibitor of α7nAChR and LY294002, the inhibitor of phosphatidylinositol 3-kinase (PI3K) blocked the suppressions of above molecules, respectively. Consistently, pretreatment with nicotine ameliorated the motor ability, restored the declines of Trx-1 and tyrosine hydroxylase (TH), and suppressed the expressions of Bip and CHOP induced by 1-Methy-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) in mice. Our results suggest that nicotine plays role in resisting MPP+/MPTP neurotoxicity through activating the α7nAChR/PI3K/Trx-1 pathway and suppressing ER stress.