ABSTRACT
The nanozyme-linked aptamer-sorbent assay (NLASA) is a rapid way to screen and characterize aptamer binding to targets. In this paper, a MnO2@AuNPs@aptamer (Apt) based NLASA coupled with colorimetric-SERS dual-mode for Staphylococcus aureus (S. aureus) detection is presented. Cu,Fe-CDs were used as the reducing agent to synthesize MnO2 and gold nanoparticles (AuNPs). Then, they were fabricated to obtain MnO2@AuNPs with oxidase (OXD)-like and SERS activities. The S. aureus aptamer was conjugated to MnO2@AuNPs and enhanced the OXD-like activity, which realized the specific capture of S. aureus in food matrices. In addition, S. aureus improves the oxidation of 2,2'-azino-bis (3-ethylbenzthiazoline-6-sulfonic acid (ABTS) but inhibits 3,3',5,5'-tetramethylbenzidine (TMB) to generate Raman-active oxTMB with MnO2@AuNPs@Apt. This sensor was used for detections of S. aureus in a concentration ranged from 101 to 107 CFU/mL with a detection limit of 0.926 CFU/mL (colorimetric) and 1.561 CFU/mL (SERS), and the recovery is 85%-105% in real samples.
ABSTRACT
In this study, we examined the effects of various sodium alginate (ALG) concentrations (0.2%-0.8%) on the functional and physicochemical characteristics of succinylated walnut glutenin (GLU-SA). The results showed that acylation decreased the particle size and zeta potential of walnut glutenin (GLU) by 122- and 0.27-fold, respectively. In addition, the protein structure unfolded, providing conditions for glycosylation. After GLU-SA was combined with ALG, the surface hydrophobicity decreased and the net negative charge and disulfide bond content increased. The protein structure was analyzed by FTIR, Endogenous fluorescence spectroscopy, and SEM, and ALG prompted GLU-SA cross-linking to form a stable three-dimensional network structure. The results indicated that dual modification improved the functional properties of the complex, especially its potential protein gel and emulsifying properties. This research provide theoretical support and a technical reference for expanding the application of GLU in the processing of protein and oil products.
Subject(s)
Juglans , Juglans/chemistry , Glycosylation , Glutens/chemistry , Nuts/chemistryABSTRACT
Nowadays, there is an increasing demand of healthier plant calcium supplements. Moringa oleifera leaves (MOL) are rich in calcium and thus are promising candidates for developing efficient calcium supplements. Here, using fermentation-based approaches, we developed a Moringa oleifera leaf ferment (MOLF), which contents higher levels of calcium. The therapeutic potential of the MOLF was also examined both in vitro and in vivo. Nine lactic acid bacteria and four yeasts were tested for better fermentation of MOL. Calcium-deficient rats were used for evaluating the therapeutic effects of MOLF. The results of liquid fermentation showed that the mixture of Lactobacillus reuteri, Lactobacillus acidophilus , and Candida utilis elevated the content of MOL calcium most strikingly, with the content of calcium increased nearly 2.4-fold (from 2.08% to 4.90%). The resulting MOLF was then subjected to cell experiments and animal experiments. The results showed that calcium absorption in Caco-2 cells in MOLF group was higher than that in CaCl2 group significantly. Interestingly, in calcium-deficient rats, MOLF treatment significantly increased the thickness of cortical bone, rat body weight, wet weight of the femur, and the femur bone density, whereas it decreased osteoclast numbers. These results indicate that microbial fermentation increased calcium bioavailability of MOL, promote the growth and development of calcium-deficient rats, bone calcium deposition, and bone growth; enhance bone strength; reduce bone resorption; and prevent calcium deficiency.
ABSTRACT
Moringa oleifera Lam. (MO) is called the "Miracle Tree" because of its extensive pharmacological activity. In addition to being an important food, it has also been used for a long time in traditional medicine in Asia for the treatment of chronic diseases such as diabetes and obesity. In this study, by constructing a library of MO phytochemical structures and using Discovery Studio software, compounds were subjected to virtual screening and molecular docking experiments related to their inhibition of dipeptidyl peptidase (DPP-IV), an important target for the treatment of type 2 diabetes. After the four-step screening process, involving screening for drug-like compounds, predicting the absorption, distribution, metabolism, excretion, and toxicity (ADME/T) of pharmacokinetic properties, LibDock heatmap matching analysis, and CDOCKER molecular docking analysis, three MO components that were candidate DPP-IV inhibitors were identified and their docking modes were analyzed. In vitro activity verification showed that all three MO components had certain DPP-IV inhibitory activities, of which O-Ethyl-4-[(α-l-rhamnosyloxy)-benzyl] carbamate (compound 1) had the highest activity (half-maximal inhibitory concentration [IC50] = 798 nM). This study provides a reference for exploring the molecular mechanisms underlying the anti-diabetic activity of MO. The obtained DPP-IV inhibitors could be used for structural optimization and in-depth in vivo evaluation.
