Mechanism Explanation on Improved Cognitive Ability of D-Gal Inducing Aged Mice Model by Lactiplantibacillus plantarum MWFLp-182 via the Microbiota-Gut-Brain Axis.

Gut microbiota can influence cognitive ability via the gut-brain axis. Lactiplantibacillus plantarum MWFLp-182 (L. plantarum MWFLp-182) was obtained from feces of long-living individuals and could exert marked antioxidant ability. Interestingly, this strain reduced the D-galactose-induced impaired cognitive ability in BALB/c mice. To comprehensively elucidate the underlying mechanism, we evaluated the colonization, antioxidant, and anti-inflammatory activities of L. plantarum MWFLp-182, along with the expression of potential genes associated with cognitive ability influenced and gut microbiota. L. plantarum MWFLp-182 enhanced the expression of anti-inflammatory cytokines, reduced the expression of proinflammatory cytokines, and increased tight junction protein expression in the colon. Moreover, L. plantarum MWFLp-182 could modify the gut microbiota. Notably, treatment with L. plantarum MWFLp-182 upregulated the expression of postsynaptic density protein-95, nuclear factor erythroid 2-related factor, nerve growth factor, superoxide dismutase, and brain-derived neurotrophic factor/neuronal nuclei, while downregulating the expression of bcl-2-associated X and malondialdehyde in the hippocampus and upregulating short-chain fatty acids against D-galactose-induced mouse brain deficits. Accordingly, L. plantarum MWFLp-182 could improve cognitive ability in a D-galactose-inducing mouse model.

Identification of two terpenoids that accumulate in Chinese water chestnut in response to fresh-cut processing.

As a form of vegetable in China, freshly cut corms of Chinese water chestnuts (Eleocharis dulcis) are well received by consumers. Few studies have investigated the metabolites present in fresh-cut E. dulcis, particularly during the storage stage. Two compounds, triterpenoids and apocarotenoids, were identified in fresh-cut E. dulcis during the late storage period using thin-layer chromatography (TLC), high-performance liquid chromatography (HPLC), and nuclear magnetic resonance (NMR) spectroscopy. The content of these two compounds gradually increased in the surface tissue of fresh-cut E. dulcis during storage. Moreover, the transcript levels of 10 genes involved in terpenoid backbone biosynthesis and five genes involved in carotenoid precursor biosynthesis were evaluated via quantitative real-time PCR (qRT-PCR). Expression of the rate-limiting enzyme-coding genes CwDXS and CwHMGS was significantly induced by wounding. CwMYC and CwbHLH18, which belong to bHLH transcription factors (TFs) IIIe and VIa subgroup, were isolated from E. dulcis corm. Phylogenetic analysis showed that CwMYC and CwbHLH18 grouped with other terpenoid-regulated bHLHs, and their transcript levels were strongly induced after fresh-cut processing. These results suggested that the biosynthesis of terpenoids and apocarotenoids in fresh-cut E. dulcis strongly depended on the transcriptional regulation of structural genes involved in the methylerythritol 4-phosphate (MEP) and mevalonate (MVA) pathways. However, the complex secondary metabolism of fresh-cut E. dulcis during late storage requires further investigation.

Study on the Mechanism of Phenylacetaldehyde Formation in a Chinese Water Chestnut-Based Medium during the Steaming Process.

The white pulp of the Chinese water chestnut (CWC) is crisp and sweet with delicious flavours and is an important ingredient in many Chinese dishes. Phenylacetaldehyde is a characteristic flavoured substance produced in the steaming and cooking process of CWC. The steaming process and conditions were simulated to construct three Maillard reaction systems which consisted of glucose and phenylalanine, and of both alone. The simulation results showed that glucose and phenylalanine were the reaction substrates for the formation of phenylacetaldehyde. The intermediate α-dicarbonyl compounds (α-DCs) and the final products of the simulated system were detected by solid-phase microextraction (SPME) and gas chromatography-mass spectrometry (GC-MS) methods. Through the above methods the formation mechanism of phenylacetaldehyde is clarified; under the conditions of the steaming process, glucose is caramelized to produce Methylglyoxal (MGO), 2,3-Butanedione (BD), Glyoxal (GO) and other α-DCs. α-DCs and phenylalanine undergo a Strecker degradation reaction to generate phenylacetaldehyde. The optimal ratio of the amount of substance of glucose to phenylalanine for Maillard reaction is 1:4. The results can provide scientific reference for the regulation of flavour substances and the evaluation of flavour quality in the steaming process of fruits and vegetables.

Identification of compounds from chufa (Eleocharis dulcis) peels by widely targeted metabolomics.

The Chinese water chestnut (CWC) is among the most widespread and economically important vegetables in Southern China. There are two different types of cultivars for this vegetable, namely, big CWC (BCWC) and small CWC (SCWC). These are used for different purposes based on their metabolic profiles. This study aimed to investigate the metabolite profile of CWC and compare the profiles of peels collected in different harvest years using ultraperformance liquid chromatography/mass spectrometry (UPLC-MS)-based metabolomics analysis. Three hundred and twenty-one metabolites were identified, of which 87 flavonoids, 25 phenylpropanoids, and 33 organic acids and derivatives were significantly different in the content of the two varieties of BCWC and SCWC. The metabolite profiles of the two different cultivars were distinguished using principle component analysis (PCA) and orthogonal projections to latent structures discriminant analysis, and the results indicated differences in the metabolite profile of Eleocharis dulcis (Burm. f.) Trin. ex Hensch. Three isomers of hydroxycoumarin, namely, O-feruloyl-4-hydroxycoumarin, O-feruloyl-3-hydroxycoumarin, and O-feruloyl-2-hydroxycoumarin, exhibited increased levels in BCWC, while p-coumaric acid and vanillic acid did not show any significant differences in their content in BCWC and SCWC peels. This study, for the first time, provides novel insights into the differences among metabolite profiles between BCWC and SCWC.

Taste Compound Generation and Variation in Chinese Water Chestnut (Eleocharis dulcis (Burm.f.) Trin. ex Hensch.) Processed with Different Methods by UPLC-MS/MS and Electronic Tongue System.

Chinese water chestnut (CWC) is popular among consumers due to its unique flavor and crisp and sweet taste. Thus far, the key substances affecting the taste compound of CWC are still unclear. In this study, we used UPLC-MS/MS and an electronic tongue system to study the effects of four typical steaming and cooking methods, cooking without peel for 10 min (PC), steaming without peel for 15 min (PS), cooking with peel for 30 min (WPC), steaming with peel for 30 min (WPS), on the taste compound generation and variation of CWC, and revealed the secret of its crisp and sweet taste. The results show that the electronic tongue can effectively identify the taste profile of CWC, and the effective tastes of CWC were umami, bitterness, saltiness, and sweetness. We screened 371 differential compounds from 640 metabolic species. Among them, nucleotides and their derivatives, carbohydrates, organic acids and their derivatives, and amino acids and their derivatives are closely related to the key taste of CWC, and these compounds affected the taste of CWC through six related metabolic pathways: oxidative phosphorylation and purine metabolism; alanine, aspartate, and glutamate; bile secretion; amino sugar and nucleotide sugar metabolism; the phenylpropane pathway; and toluene degradation. This study reveals the potential metabolic causes of taste compound generation and variation in the taste of CWC.

Comparison of flavonoids and phenylpropanoids compounds in Chinese water chestnut processed with different methods.

Different processing methods of Chinese water chestnut (CWC; Eleocharis dulcis (Burm.f.) Trin. ex Hensch.) steaming with skin (WPC), cooking with skin (WPS), steaming with peeling (PS), fresh cutting (FF) and cooking with peeling (PC) were compared. Liquid chromatography-mass spectrometry was used to analyze the metabolic profiles of the processed samples. A total of 454 metabolites, including 123 flavonoids and 57 phenylpropanoids, were characterized. The flavonoid and phenylpropanoid profiles were distinguished using PCA. Eighteen flavonoids and six phenylpropanoids were detected and quantitated in the WPC and WPS samples but not in the FF, PC and PS samples. In addition to the O-hexoside of tricin, kaempferol and luteolin were the predominant flavonoids in the WPC and WPS samples, and all three compounds were higher in the WPC and WPS samples than in the FF sample. This study provides new results regarding differences in the metabolite profile of CWC processed with different methods.

Fabrication of Delivery Gels with Micellar Casein Concentrates (MCC) Using Microfiltration Embedding Lactobacillus Rhamnosus GG (LGG): Effect of Temperature on Structure, Rheological Behavior, and Texture.

To obtain natural protein gels as delivery systems loading with probiotics and protect the probiotics from heat treatment, we fabricated casein-based gels using micellar casein concentrates (MCC) via microfiltration and then embedded with Lactobacillus Rhamnosus GG (LGG). Rheological analysis indicated that MCC with a protein concentration of 12% would form gels greatly. The results of SDS-polyacrylamide gel electrophoresis showed that the contents of macromolecule in the gels increased as the heat treatment time is prolonged. After heat treatment, a fibrillated structure and a more stable structure were obtained in MCC-LGG gels by scanning electron microscopy and Fourier transform infrared spectroscopy, respectively. The different changes of rheological behavior and texture of the gels were evaluated using a rheometer and texture analyzer, respectively. Similarly, centrifugation could reduce the property modified by heat inducing and contribute to LGG embedding completely. Importantly, LGG with a survival rate of 7.12% was in the gels after heat treatment at 75 °C for 10 min. Results showed that MCC could offer a protecting circumstance for living LGG cells from heat treatment. Therefore, MCC-LGG gels would be a potential healthy food for improving intestinal microflora in the dairy industry.

The ameliorative effect of Lactobacillus plantarum-12 on DSS-induced murine colitis.

Some strains of lactobacilli can exert beneficial effects on a host when ingested in an adequate dose, such as immunoregulation and anti-inflammatory activities. In this study, the survival abilities under simulated gastrointestinal conditions, adhesion abilities on HT-29 cell monolayers, and hemolytic activities of four Lactobacillus plantarum strains were assessed. Among the four strains, L. plantarum-12 showed the higher survival rate under simulated gastrointestinal conditions and adhesion index on the HT-29 cell monolayers, exhibited γ-haemolytic activity and had no biological amine producing ability. L. plantarum-12 was administered to dextran sodium sulfate (DSS)-induced ulcerative colitis (UC) Balb/c mice by oral gavage for 10 days. It was observed that the UC Balb/c mice showed symptoms of colonic atrophy, intestinal histopathological change, gut microbial disturbance, and pro-inflammatory cytokine expression. L. plantarum-12 administration remarkably attenuated DSS-induced UC in mice. L. plantarum-12 administration could restore gut microbiota by increasing beneficial bacteria such as Lactobacillus and decreasing intestinal pathogenic bacteria like Proteobacteria. L. plantarum-12 administration could improve immunity via activating the janus kinase-signal transducer and the activator of the transcription (JAK-STAT) pathway and up-regulating adenosine deaminase (ADA) and interferon-induced protein with tetratricopeptide repeats 1 protein (IFIT1), and enforce the intestinal barrier function by up-regulating mucin 2 (MUC2) protein expression. In conclusion, L. plantarum-12 could attenuate DSS-induced UC in Balb/c mice by ameliorating intestinal inflammation, and restoring the disturbed gut microbiota. L. plantarum-12 could be used as promising probiotics to ameliorate colitis.

Silver nanosol SERS quantitative analysis of ultratrace biotin coupled N-doped carbon dots catalytic amplification with affinity reaction.

Highly catalytic and stable N-doped carbon dots (N-CDs) were prepared rapidly by microwave procedure using glucose as precursor and ammonium sulfite as N-dopant. The reduction of AgNO3 by trisodium citrate (TCA) was slow to form nanosilver (AgNP), and the N-CDs exhibited strong catalysis of the AgNP reaction. The formed AgNPs were used as indicator in the presence of Vitoria blue B (VBB) molecule probe with a SERS peak at 1615 cm-1. With the increase of nancatalyst N-CDs concentration, the AgNP reaction speed up, and the SERS peak of VBB enhanced linearly due to formation of more AgNPs as substrate. In the presence of avidin (Ad), the SERS peak weakened. Upon addition of biotin, the SERS peak enhanced due to turn on the indicator nanoreaction. The enhanced SERS signal had a good linear relationship with the biotin concentration in range of 0.0006-0.021 ng/mL, with a detection limit of 0.3 pg/mL.

A new and facile nanosilver SPR colored method for ultratrace arsenic based on aptamer regulation of Au-doped carbon dot catalytic amplification.

Here, Au-doped carbon dots (CDAu) nanosols with good stability were prepared by hydrothermal reaction method. We found that CDAu can efficiently catalyze the nanoreaction of reducing AgNO3 by glucose, and at 420 nm，the reaction products of yellow spherical silver nanosol exhibit an intense surface plasmon resonance (SPR) absorption peak. The nucleic acid aptamers (Apt) can be adsorbed on the surface of carbon dots, so that their catalytic activity was suppressed, the nanosilvers were reduced, the solution color becomes lighter, and the Abs value was weakened. When As3+ was added, it forms a stable conjugate with the Apt, releases free carbon dots, restored its catalytic activity, and the color and Abs signals enhanced linearly. Based on the Apt regulation and the catalytic amplification effect of CDAu on AgNO3-glucose, a new extremely sensitive SPR spectrophotometric method for the determination of arsenic ion content of 0.025-0.75 µg/L was established, and the detection limit of As3+ is 0.01 µg/L.

Identification of compounds from chufa (Eleocharis dulcis) peels with inhibitory acrylamide formation activity

Abstract Five compounds were isolated from the peels of chufa (Eleocharis dulcis (Burm.f.) Trin. ex Hensch., Cyperaceae). The chemical structures were determined by various spectroscopic analysis methods, including 1D and 2D NMR, and by comparison with literature data. All compounds were isolated for the first time from the peels of chufa. Compounds orcinol glucoside, leonuriside A, 2-hydroxymethyl-6-(5-hydroxy-2-methyl-phenoxy-methyl)-tetra-hydro-pyran-3,4,5-triol, and 1,4-dihydroxy-3-methoxy-phenyl-4-O-β-D-glucopyranoside showed good acrylamide formation activity, and acrylamide inhibition rates were 30.24, 32.81, 30.53, and 28.18%, respectively.

Improved structure-stability and packaging characters of crosslinked collagen fiber-based film with casein, keratin and SPI.

BACKGROUND: To improve the structure-stability and packing characters of collagen fiber, we manufactured crosslinked collagen fiber (CColF)-based edible films using transglutaminase (TGase). Then we made a comparison on structure-stability and packing characteristics among the CColF-based films loaded with casein (CN), keratin (KRT) and soy protein isolate (SPI), respectively. RESULTS: Observed from scanning electron microscopy (SEM), the CColF loaded with CN, KRT and SPI showed some unique morphology of the additional proteins. The CColF-protein films performed better packing characteristics including barrier properties, mechanical properties and thermal-stability properties, compared with CColF films. Importantly, with 500 g kg-1 CN (of CColF) addition, CColF-based films possessed a greater thermal stability than the other films judged from differential scanning calorimetry (DSC). Meanwhile, the CColF loaded with 100 g kg-1 CN provided a higher value of tensile strength (TS) and the CColF loaded with 100 g kg-1 KRT showed a higher value in elongation-at-break (EAB) than the other films. CONCLUSION: In conclusion, the collagen fiber-based edible films with better structure-stability and packing characteristics for food packaging was obtained which could be an advantage to promote the development of the application of collagen in packing products. © 2019 Society of Chemical Industry.

A novel gold nanosol SERS quantitative analysis method for trace Na+ based on carbon dot catalysis.

The Ca-doped carbon dots (CDCa) exhibited strong catalysis of HAuCl4-H2O2 reaction to produce gold nanoparticle (AuNP), using Vitoria blue 4R (VB4r) as molecular probe, it appeared a strong surface enhanced Raman scattering (SERS) peak at 1615 cm-1 in the AuNP nanosol substrate. When catalyst CDCa increased, the SERS peak enhanced linearly owing to AuNPs increasing, that is, the AuNP concentration is linear to SERS signal. Potassium pyroantimonate (PA) ligand can adsorb on CDCa surface to inhibit the catalysis and cause the SERS peak decreasing. The analyte of Na+ reacts with PA to produce the stable precipitate of [Na2(PA)] and free CDCa catalyst. The more Na+, the more CDCa released, and the stronger SERS signal due to more AuNP substrate. Accordingly, a SERS quantitative analysis method for Na+ was developed based on CDCa catalytic SERS reaction, with a linear range of 0.004-0.043 µmol/L, and a detection limit of 0.0019 µmol/L Na.

Doped N/Ag Carbon Dot Catalytic Amplification SERS Strategy for Acetamiprid Coupled Aptamer with 3,3'-Dimethylbiphenyl-4,4'-diamine Oxidizing Reaction.

The as-prepared co-doped N/Ag carbon dot (CDNAg) has strong catalysis of H2O2 oxidation of 3,3'-dimethylbiphenyl-4,4'-diamine (DBD). It forms an oxidation product (DBDox) with surface-enhanced Raman scattering (SERS) activity at 1605 cm-1 in the silver nanosol substrate, and a CDNAg catalytic amplification with SERS analytical platform can be structured based on aptamer (Apt) with the DBD oxidizing reaction. For example, the aptamer (Apt) of acetamiprid (ACT) can be adsorbed on the surface of CDNAg, resulting in inhibited catalytic activity, the reduced generation of DBDox, and a weakened SERS intensity. When the target molecule ACT was added, it formed a stable Apt-ACT complex and free CDNAg that restored catalytic activity and linearly enhanced the SERS signal. Based on this, we proposed a new quantitative SERS analysis method for the determination of 0.01⁻1.5 µg ACT with a detection limit of 0.006 µg/L.

Preparation of Highly Catalytic N-Doped Carbon Dots and Their Application in SERS Sulfate Sensing.

Carbon dots (CD) have excellent stability and fluorescence activity, and have been widely used in fluorescence methods. However, there are no reports about using CD as catalysts to amplify SERS signals to detect trace sulfate. Thus, preparing CD catalysts and their application in SERS sulfate-sensing are significant. In this article, highly catalytic N-doped carbon dots (CDN) were prepared by a hydrothermal procedure. CDN exhibited strong catalysis of the gold nanoparticle (AuNP) reaction between HAuCl4 and H2O2. Vitoria blue 4R (VB4R) has a strong SERS peak at 1614 cm-1 in the formed AuNP sol substrate. When Ba2+ ions were added, they were adsorbed on a CDN surface to inhibit the CDN catalytic activity that caused the SERS peak decreasing. Upon addition of analyte SO42-, a reaction with Ba2+ produced stable BaSO4 precipitate and CDN, and its catalysis recovered to cause SERS intensity increasing linearly. Thus, an SERS method was developed for the detection of 0.02⁻1.7 µmol/L SO42-, with a detection limit of 0.007 µmol/L.

A simple gold nanoplasmonic SERS method for trace Hg2+ based on aptamer-regulating graphene oxide catalysis.

The as-prepared graphene oxide (GO) exhibited a strong catalytic effect on reduction of HAuCl4 by trisodium citrate to form gold nanoplasmons (AuNPs) with a strong surface-enhanced Raman scattering (SERS) effect at 1615 cm-1 in the presence of molecular probe Victoria blue 4R (VB4r). SERS intensity increased with nanocatalyst GO concentration due to the formation of more AuNP substrates. The aptamer (Apt) of Hg2+ can bind to GO to form Apt-GO complexes, which can strongly inhibit nanocatalysis. When target Hg2+ is present, the formed stable Hg2+ -Apt complexes are separated from the GO surface, which leads to GO catalysis recovery. The enhanced SERS signal was linear to Hg2+ concentration in the range 0.25-10 nmol/L, with a detection limit of 0.08 nmol/L Hg2+ . Thus, a new gold nanoplasmon molecular spectral analysis platform was established for detecting Hg2+ , based on Apt regulation of GO nanocatalysis.

A Sensitive Gold Nanoplasmonic SERS Quantitative Analysis Method for Sulfate in Serum Using Fullerene as Catalyst.

Fullerene exhibited strong catalysis of the redox reaction between HAuCl4 and trisodium citrate to form gold nanoplasmon with a strong surface-enhanced Raman scattering (SERS) effect at 1615 cm−1 in the presence of Vitoria blue B molecule probes. When fullerene increased, the SERS peak enhanced linearly due to formation of more AuNPs as substrate. Upon addition of Ba2+, Ba2+ ions adsorb on the fullerene surface to inhibit the catalysis of fullerene that caused the SERS peak decreasing. Analyte SO42− combined with Ba2+ to form stable BaSO4 precipitate to release free fullerene that the catalysis recovered, and the SERS intensity increased linearly. Thus, a new SERS quantitative analysis method was established for the detection of sulfate in serum samples, with a linear range of 0.03⁻3.4 μM.

A Sensitive Resonance Rayleigh Scattering Method for Na+ Based on Graphene Oxide Nanoribbon Catalysis.

The gold nanoparticle reaction of HAuCl4-H2O2 was very slow under 60°C, and the as-prepared graphene oxide nanoribbons (GONRs) exhibited strong catalysis of the reaction to form gold nanoparticles (AuNP) that appeared a resonance Rayleigh scattering (RRS) peak at 550 nm. Upon addition of potassium pyroantimonate (PA) ligand, it was adsorbed on the GONRs surface to inhibit the catalysis to cause the RRS peak decreasing. When the analyte of Na+ was added, the coordination reaction between PA and Na+ took place to form the stable complexes of [Na2(PA)] to release free GONRs catalyst that resulted in the RRS peak increasing linearly. Accordingly, a new and sensitive RRS method for Na+ was established, with a linear range of 0.69-25.8 nmol/L and a detection limit of 0.35 nmol/L Na+.

A sensitive surface-enhanced Raman scattering method for chondroitin sulfate with Victoria blue 4R molecular probes in nanogold sol substrate.

Using silver nanoparticles (AgNPs) as the nanocatalyst, l-cysteine rapidly reduced HAuCl4 to make a stable gold nanoparticle sol (Ag/AuNP) that had a high surface-enhanced Raman scattering (SERS) activity in the presence of Victoria blue 4R (VB4r) molecular probes. Under the selected conditions, chondroitin sulfate (Chs) reacted with the VB4r probes to form associated complexes that caused the SERS effect to decrease to 1618 cm-1 . The decreased SERS intensity was linear to the Chs concentration in the range 3.1-500 ng/ml, with a detection limit of 1.0 ng/ml Chs. Accordingly, we established a simple and sensitive SERS quantitative analysis method to determine Chs in real samples, with a relative standard deviation of 1.47-3.16% and a recovery rate of 97.6-104.2%.

A facile and sensitive peptide-modulating graphene oxide nanoribbon catalytic nanoplasmon analytical platform for human chorionic gonadotropin.

The nanogold reaction between HAuCl4 and citrate is very slow, and the catalyst graphene oxide nanoribbon (GONR) enhanced the nanoreaction greatly to produce gold nanoparticles (AuNPs) that exhibited strong surface plasmon resonance (SPR) absorption (Abs) at 550 nm and resonance Rayleigh scattering (RRS) at 550 nm. Upon addition of the peptide of human chorionic gonadotropin (hCG), the peptide could adsorb on the GONR surface, which inhibited the catalysis. When hCG was added, peptides were separated from the GONR surface due to the formation of stable peptide-hCG complex, which led to the activation of GONR catalytic effect. With the increase in hCG concentration, the RRS and Abs signal enhanced linearly. The enhanced RRS value showed a good linear relationship with hCG concentration in the range of 0.2-20 ng/mL, with a detection limit of 70 pg/mL. Accordingly, two new GONR catalytic RRS/Abs methods were established for detecting hCG in serum samples.