White hyacinth bean polysaccharide ameliorates diabetes via microbiota-gut-brain axis in type 2 diabetes mellitus rats.

Gut played a potent role in onset and progression of metabolic disorders, presenting an exciting direction for diabetes prevention. Here, the anti-diabetic effects of White hyacinth bean polysaccharides (WHBP) were observed, including the reduction of blood glucose levels and improvement of intestinal impairment in type 2 diabetes mellitus (T2DM) rats. Further data concerning intestinal protection suggested that WHBP restored intestinal barrier, as evidenced by inhibition of intestinal pathological damage, up-regulation of Zonula occluden-1 expression and manipulation of the redox system in T2DM rats. Moreover, WHBP-mediated anti-diabetic effects were in parallel with the adjustment of changes in gut microbiota composition of T2DM rats. Meanwhile, hypersecretion of corticotropin-releasing hormone, adrenocorticotropic hormone, and corticosterone levels, which were critical coordinators of the hypothalamic-pituitary-adrenal (HPA) axis, were suppressed in T2DM rats exposed to WHBP, indicating that WHBP-mediated health benefits were referring to regulate brain feedback in reduction of HPA axis. Concomitantly, further suggested and expanded on gut-brain communication by data of microbial metabolites short-chain fatty acids, mediators of gut-brain interactions, were remarkably raised in cecum contents of T2DM rats subjected to WHBP. Collectively, WHBP performed anti-diabetic effects were associated with control of microbiota-gut-brain axis implicated in intestinal barrier, HPA axis, gut microbiota and their metabolites.

Fabrication of enzyme reactor utilizing magnetic porous polymer membrane for screening D-Amino acid oxidase inhibitors.

In this work, a unique D-amino acid oxidase reactor for enhanced enzymolysis efficiency is presented. A kind of magnetic polymer matrices, composed of iron oxide nanoparticles and porous polymer membrane (poly styrene-co-maleic anhydride), was prepared. With covalent bonding D-Amino acid oxidase on the surface of the matrices and characterization of scanning electron microscope and vibrating sample magnetometer, it demonstrated that the membrane enzyme reactor was successfully constructed. The enzymolysis efficiency of the enzyme reactor was evaluated and the apparent Michaelis-Menten constants of D-Amino acid oxidase were determined (Km was 1.10mM, Vmax was 23.8mMmin-1) by a chiral ligand exchange capillary electrophoresis protocol with methionine as the substrate. The results indicated that the enzyme reactor could exhibit good stability and excellent reusability. Importantly, because the enzyme and the substrate could be confined into the pores of the matrices, the enzyme reactor displayed the improved enzymolysis efficiency due to the confinement effect. Further, the prepared enzyme reactor was applied for D-Amino acid oxidase inhibitors screening. It has displayed that the proposed protocol could pave a new way for fabrication of novel porous polymer membrane based enzyme reactors to screen enzyme inhibitors.

Ratiometric Fluorescent Polymeric Thermometer for Thermogenesis Investigation in Living Cells.

Intracellular temperature has a fundamental effect on cellular events. Herein, a novel fluorescent polymer ratiometric nanothermometer has been developed based on transferrin protein-stabilized gold nanoclusters as the targeting and fluorescent ratiometric unit and the thermosensitve polymer as the temperature sensing unit. The resultant nanothermometer could feature a high and spontaneous uptake into the HeLa cells and the ratiometric temperature sensing over the physiological temperature range. Moreover, the precise temperature sensing for intracellular heat generation in HeLa cells following calcium ions stress has been achieved. This practical intracellular thermometry could eliminate the interference of the intracellular surrounding environment in cancer cells without a microinjection procedure, which is user-friendly. The prepared new nanothermometer can provide tools for unveiling the intrinsic relationship between the intracellular temperature and ion channel function.

A chiral ligand exchange CE system for monitoring inhibitory effect of kojic acid on tyrosinase.

A facile chiral ligand exchange capillary electrophoresis (CLE-CE) system with Zn(II)-L-alanine as the chiral selector in the presence of ß-cyclodextrin has been developed for enantioseparation of dansyl amino acids. The influence of the key factors, such as buffer pH, the ratio of Zn (II) to ligand, the concentration of ß-cyclodextrin and the concentration of the complex, were investigated in detail when D, L-Tyr and D, L-Thr were selected as the model analytes. The proposed method showed favorable quantitative analysis property of dansyl D, L-tyrosine with good linearity (r(2)≥0.999) and reproducibility (RSD≤3.8%), then, it was applied in studying the activity of tyrosinase through the determination of L-tyrosine concentration variation after being incubated with the enzyme. Further, the inhibitory efficiency of kojic acid and soy sauce on the tyrosinase was investigated. The IC50 of kojic acid obtained from the sigmoidal inhibitory curve was 21.35 µM. The results imply that the proposed CLE-CE system has the potential in exploring the activity of enzyme and screening the inhibitors of enzyme.