Dependable, specific and rapid diagnostic methods for severe acute respiratory syndrome β-coronavirus (SARS-CoV-2) detection are needed to promote public health interventions for coronavirus disease ...2019 (COVID-19). Herein, we have established an entropy-driven amplified electrochemiluminescence (ECL) strategy to detect the RNA-dependent RNA polymerase (RdRp) gene of SARS-CoV-2 known as RdRp-COVID which as the target for SARS-CoV-2 plays an essential role in the diagnosis of COVID-19. For the construction of the sensors, DNA tetrahedron (DT) is modified on the surface of the electrode to furnish robust and programmable scaffolds materials, upon which target DNA-participated entropy-driven amplified reaction is efficiently conducted to link the Ru (bpy)32+ modified S3 to the linear ssDNA at the vertex of the tetrahedron and eventually present an “ECL on” state. The rigid tetrahedral structure of the DT probe enhances the ECL intensity and avoids the cross-reactivity between single-stranded DNA, thus increasing the sensitivity of the assays. The enzyme-free entropy-driven reaction prevents the use of expensive enzyme reagents and facilitates the realization of large-scale screening of SARS-CoV-2 patients. Our DT-based ECL sensor has demonstrated significant specificity and high sensitivity for SARS-CoV-2 with a limit of detection (LOD) down to 2.67 fM. Additionally, our operational method has achieved the detection of RdRp-COVID in human serum samples, which supplies a reliable and feasible sensing platform for the clinical bioanalysis.
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•RdRp-COVID is a characteristic gene sequence of SARS-CoV-2.•DNA tetrahedron was involved in the construction of the capture probe skeleton.•Entropy-driven reaction was employed in the signal amplification.•The biosensor exhibited down to 2.67 fM sensitivity for RdRp-COVID gene.
Objective: To observe the relationships between the electrocardiogram (ECG) and quiet biochemical, heart rate variability (HRV) and electroencephalogram (EEG) indicators, to establish the Index ...system for the risk prediction to graded exercise test (GXT) in men from 40 to 49yr. Materials: 173 men from 40-49 year of age (44.0±3.5yr) without cardiovascular disease and other diseases. Methods: Answered their physical activity (PA) by the international physical activity questionnaire (IPAQ). To test blood press (BP), heart rate (HR), pulse wave velocity (PWV), total cholesterol (TC), total triglyceride (TG), high density lipoprotein cholesterol (HDL-c), low density lipoprotein cholesterol (LDL-c), myocardium enzymes, high sensitive C reactive protein (hCRP), observation pressure (OP) and low frequency/high frequency (LF/HF) in the quiet at the same day. The GXT was performed on a cycle ergo-meter with GXT starting with 25 w and adding 25 w at 2 min intervals until reached abnormal change in ST-segment (ST). The values of GXT, ECG and oxygen uptake (VO2) were recorded. To analyze the relationships between ST and other indictors by multiple regression analysis; To build the regression equations by stepwise regression. The significance was p<0.05; The highly significance was p<0.01. Results: 1: 28 men had abnormal change in ST; 2: For the abnormal men, HDL-c, OP of EEG and diastolic blood pressure (DBP) in the quiet state had relationships in ST of ECG, p<0.05. 3: The equation was Y=-0.446+0.004X1-0.042X2+0.002X3. Y was the change of ST, X1 was value of DBP, X2 was value of HDL-c, X3 was value of OP. R=0.733，R2=0.538. Conclusion: 1. The values of HDL-c, DBP and OP of EEG can be used to predict the abnormal change of ST in 40-49yr Chinese men in GXT.
To benefit the consumers with a variety of health benefits, the incorporation of wheat bran into the bread formula has been widely conducted. This leads to changes in the rheological properties of ...dough that is associated with the overall quality of bakery products. This review has demonstrated the utility of a wide range of measurements at large and small deformations for determining dough rheological properties. Particularly, the rheological models have been proven with a good application in characterizing the viscoelastic behavior of whole wheat dough during breadmaking. The objective of this review was to build up a solid theorical foundation on how the rheological properties and baking performance of doughs are modified by manipulating the ingredient (i.e., the composition of gluten proteins from refined wheat flour, the properties of dietary fibre, the flour particle size, and the addition of hydrocolloids and enzymes) and processing (i.e., the time, temperature, speed and work input of mixing, the time, speed and geometry type of kneading, and the resting time) conditions throughout breadmaking processes. We also aimed to demonstrate the interactions of gluten proteins, dietary fibre and water molecules that play critical roles in affecting the dough rheology and the resultant bread quality. This will bring us a future research focus on how the gluten protein-dietary fibre-water interactions respond to the effects of dough formulation and processing parameters.
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•Whole wheat dough rheology was determined at large and small deformations.•Rheological models have a good application in describing dough rheology.•Ingredients and processing affect dough rheology and baking performance.•Gluten protein-dietary fibre-water interactions were affected by dough formulation.
MicroRNA (miRNA) has become an important biomarker candidate for cancer diagnosis, prognosis, and therapy. In this study, we have developed a novel fluorescence method for sensitive and specific ...miRNA detection via duplex specific nuclease (DSN) signal amplification and demonstrated its practical application in biological samples. Malachite green (MG) was employed as a “label-free" signal transducer since fluorescence of MG could be enhanced by 100-fold when MG were binding to a G-quadruplex structure formed within the d(G2T)13G sequence. The proposed signal amplification strategy is an integrated “biological circuit” designed to initiate a cascade of enzymatic reactions in order to detect, amplify, and measure a specific miRNA sequence by using the isothermal cleavage property of a DSN. The circuit is composed of two molecular switches operating in series: the amplification reaction activated by a specific miRNA and the strand-displacement polymerization reaction designed to initiate molecular beacon-assisted amplification and signal transduction by using MG/G-quadruplex complex. The hsa-miR-141 (miR141) was chosen as a target miRNA because its level specifically abnormal in a wide range of common human cancers including breast, lung, colon, and prostate cancer. The proposed method allowed quantitative sequence-specific detection of miR141 (with a detection limit of 1.03pM) in a dynamic range from 1pM to 10μM, with an excellent ability to discriminate differences in miRNAs. Moreover, the detection assay was applied to quantify miR141 in cancerous cell lysates. On the basis of these findings, we believe that this proposed sensitive and specific assay has great potential as a miRNA quantification method for use in biomedical research and clinical diagnosis.
•A new method for microRNA assay in complex biological samples is reported.•This method employed two stages DSN-assisted target recycling signal amplification strategy.•This method employed Malachite green/G-quadruplex complex as a signal transducer.•MB1 is modified with 2-OMe-RNA on its stem and target DNA part to prevent DSN cleavage.
Scope
Kudingcha (KDC) from Ilex kudingcha and Fuzhuan brick tea (FBT) are popular beverages in China, and their preventive and therapeutic roles in metabolic disorders have been reported. However, ...the relationship between the gut microbiota modulatory effects of KDC and FBT and prevention of obesity is still not clearly understood.
Methods and results
KDC and FBT are tested individually for their capacities to prevent obesity and modulate the gut microbiota in high‐fat diet (HFD) fed C57BL/6J mice. The results show that both KDC and FBT supplementation could modulate oxidative injury, inflammation, lipid metabolism, and reduce HFD induced obesity significantly. Both KDC and FBT could enhance the diversity of gut microbiota. KDC could reduce the relative abundance of Erysipelotrichaceae, while FBT could reduce the ratio of Firmicutes to Bacteroidetes and enhance the relative abundance of Bifidobacteriaceae.
Conclusion
These findings suggest that KDC and FBT could attenuate features of the metabolic syndrome in HFD‐fed mice, which might be due to the modulation of gut microbiota by KDC and FBT.
The relationship between the gut microbiota modulatory effects of Kudingcha (KDC) and Fuzhuan brick tea (FBT) and prevention of obesity is investigated in this work. The HFD‐induced dysbiosis of gut microbiota is reversed by the consumption of KDC and FBT, and the diversity of gut microbiota could be enhanced by KDC and FBT.
Sialic acid-binding immunoglobulin (Ig)-like lectins (Siglecs) is a type I transmembrane receptor on the cell surface. Siglec-5, as one of the Siglecs family, play an important role as an inhibitory ...receptor for leukocytes in the human body. The development of novel siglec-5 assays can help to study the pathogenesis of related diseases as well as to develop novel therapeutic drugs. We use catalytic hairpin assembly (CHA) amplification strategy combined with CRISPR-Cas12a′s side-cutting feature to build a 2D ultra-thin Ti3C2Tx (MXene) based electrochemiluminescence (ECL) biosensor for the detection of Siglec-5. By using this ECL biosensor, the cleavage of CRISPR-Cas12a is reasonably combined with CHA-mediated isothermal amplification, thereby realizing the sensitive amplification assay Siglec-5 with 20.22 fM sensitivity. By introducing pairs of sites that are not in the same double-stranded DNA into the DNA duplex, the hybridization sequence of CRISPR-Cas12a complements the targeting mechanism to enhance indirect Siglec-5 amplification assay. Also, the double-strand DNA (dsDNA) design based on CRISPR-Cas12a amplification allows the same CRISPR RNA (crRNA, also known as guide RNA (gRNA)) to detect the output of DNA duplexes from different intermediate DNAs, which provides a common way for biomarker detection based on the conversion of protein analytes to intermediate DNA strategy. This work extends the application scope of CRISPR-Cas12a to the construction of ECL biosensors, evaluates the role of lectins, which can be used for the biochemical research and clinical diagnosis of protein markers. This is the first investigative work exploring the Trans-Cleavage activity of CRISPR-Cas12a for Mxene-based ECL biosensor establishment to the best of our knowledge.
•Analysis Siglec provides new ideas for studying coronavirus.•We built a MXene based ECL biosensor for the detection of Siglec-5.•The biosensor employed CHA amplification strategy combined with CRISPR-Cas12a side-cutting feature.•The biosensor realizing the sensitive amplification assay Siglec-5 with 29.36 fM.
An increasing amount of evidence suggests that the gut microbiota composition and structure contribute to the pathophysiology of metabolic syndrome (MS), which has been put forward as a new target in ...the treatment of diet-induced MS. In this work, we aimed to investigate effects of Fuzhuan brick tea polysaccharides (FBTPS) on MS and gut microbiota dysbiosis in high-fat diet (HFD) fed mice and to further investigate whether its attenuation of MS is related to the modulation of gut microbiota. The results showed that FBTPS intervention could significantly attenuate metabolic syndrome in HFD-induced mice. Based on results of sequencing, FBTPS treatment could increase the phylogenetic diversity of HFD-induced microbiota. FBTPS intervention could significantly restore the HFD-induced increases in relative abundances of Erysipelotrichaceae, Coriobacteriaceae, and Streptococcaceae. Spearman’s correlation analysis showed that 44 key OTUs were negatively or positively associated with MS. Our results suggested that FBTPS could serve as a novel candidate for prevention of MS in association with the modulation of gut microbiota.
•Chlorogenic acid (CGA) and high deacetylation degree of chitosan was conjugated.•The substitution degree of CGA reached up to 144.8mg CGA equivalent/g complex.•The solubility of conjugate was ...greatly enhanced due to conjugation.•The conjugate exhibited higher inhibitory effect on lipid peroxidation than CGA.•The conjugate had higher inhibition on β-carotene-linoleic acid bleaching than CGA.
Chlorogenic acid-chitosan conjugate was synthesized by introducing of chlorogenic acid onto chitosan with the aid of 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide and hydroxybenzotriazole. The data of UV–vis, FT-IR and NMR for chlorogenic acid-chitosan conjugates demonstrated the successful conjugation of chlorogenic acid with chitosan. Compared to chitosan, chlorogenic acid-chitosan conjugates exhibited increased solubility in distilled water, 1% acetic acid solution (v/v) or 50% ethanol solution (v/v) containing 0.5% acetic acid. Moreover, chlorogenic acid-chitosan conjugates showed dramatic enhancements in metal ion chelating activity, total antioxidant capacity, scavenging activities on 2,2′-azino-bis-(3-ethylbenzothiazoline-6-sulphonic acid) and superoxide radicals, inhibitory effects on lipid peroxidation and β-carotene-linoleic acid bleaching, and protective effect on H2O2-induced oxidative injury of PC12 cells. Particularly, chlorogenic acid-chitosan conjugate exhibited higher inhibitory effects on lipid peroxidation and β-carotene-linoleic acid bleaching than chlorogenic acid. The results suggested that chlorogenic acid-chitosan conjugates could serve as food supplements to enhance the function of foods in future.
•CS/GA-CS/GA-g-CS, gelatin, glycerol and Tween20 were utilized to formulate films.•Moisture content and water vapor permeability decreased in GA-CS and GA-g-CS films.•Mechanical property was improved ...with the increase of GA concentration.•Antioxidant and antimicrobial activities of GA-g-CS films exceeded GA-CS films.
Gallic acid-grafted-chitosan (GA-g-CS) was synthesized in the presence of 1-ethyl-3-(3′-dimethylaminopropyl) carbodiimide and hydroxybenzotriazole under room temperature. To develop a kind of newly functional film, CS, gelatin, glycerol and Tween 20 were utilized to prepare CS-based composite films with incorporated GA (GA-CS) or conjugated GA (GA-g-CS), and the films were characterized in aspects of physical and functional properties, as well as microstructures. With the increasing of GA concentration, there was a reduction in transmittance, elongation at break and water vapor permeability (WVP) for GA-CS film. For GA-CS films, the higher tensile strength and lower WVP could be obtained when GA was evenly distributed across the films. Different from the GA-CS films, water solubility, swelling ratio, water vapor permeability and scavenging activities on 2,2-Diphenyl-1-picrylhydrazyl/2,2'-azino-bis-(3-ethylbenzothiazoline-6-sulphonic acid) radicals were enhanced for GA-g-CS films, which could be ascribed to the rough surface morphology. The GA-g-CS films exhibited enhanced water vapor permeability when the substitution degree of GA increased. Also, the antimicrobial activities of GA-g-CS films were superior to those of GA-CS films. Our present work developed a way to prepare GA-g-CS films that owned many desirable properties and could be explored as promising biomaterials in food packaging.
Selenium (Se) is a trace mineral micronutrient essential for human health. The diet is the main source of Se intake. Se‐deficiency is associated with many diseases, and up to 1 billion people suffer ...from Se‐deficiency worldwide. Cereals are considered a good choice for Se intake due to their daily consumption as staple foods. Much attention has been paid to the contents of Se in cereals and other foods. Se‐enriched cereals are produced by biofortification. Notably, the gap between the nutritional and toxic levels of Se is fairly narrow. The chemical structures of Se compounds, rather than their total contents, contribute to the bioavailability, bioactivity, and toxicity of Se. Organic Se species show better bioavailability, higher nutritional value, and less toxicity than inorganic species. In this paper, we reviewed the total content of Se in cereals, Se speciation methods, and the biological effects of Se species on human health. Selenomethionine (SeMet) is generally the most prevalent and important Se species in cereal grains. In conclusion, Se species should be considered in addition to the total Se content when evaluating the nutritional and toxic values of foods such as cereals.
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