Detection of glycoprotein through fluorescent boronic acid-based molecularly imprinted polymer.

A novel strategy based on the fluorescent molecularly imprinted polymers (FMIP) for specific recognition and sensitive sensing glycoprotein from biological samples was developed. The FMIP prepared by introducing a fluorescent boronic acid quinoline-based on the PGMA/EDMA bead surface and assembled a glycoprotein molecularly imprinted polymer using surface imprinting technology. The resultant material showed specific recognition to model glycoprotein. At the same time, the change of fluorescence caused by the amount of model glycoprotein could achieve quantitative determination. The method provided a good linear relationship of the concentrations of HRP in the range of 0.05-1 µM, and the detection limit was 0.02 µM. It is 10 times lower than the previous fluorescence nanosensor for glycoprotein. The established method combined the desired selectivity of molecularly imprinted polymers and high sensitivity of fluorescence spectroscopy. The influence of background impurities could be effectively eliminated. The outstanding features guarantee that it can be successfully applied to detect glycoprotein from biological samples under physiological conditions.

Delta-Like-1 Changes the Immunomodulatory Property of OP9 Cells.

As stromal cells and recently confirmed mesenchymal stem cells, OP9 cells support hematopoiesis stem cell (HSC) differentiation into the B lymphocyte lineage, yet Delta-like-1 (DL1) overexpressing OP9 (OP9DL1) cells promote the development of early T lymphocytes from HSC. However, the immunomodulatory capacity of OP9 or OP9DL1 on mature B and T cell proliferation has not been elucidated. Here, we show that OP9 and OP9DL1 have similar proliferation capacities and immunophenotypes except DL1 expression. Compared with OP9, OP9DL1 displayed more osteogenesis and less adipogenesis when cultured in the respective induction media. Both OP9 and OP9DL1 inhibited mature B and T cell proliferation. Furthermore, OP9 showed stronger inhibition on B cell proliferation and OP9DL1 exhibited stronger inhibition on T cell proliferation. With stimulation, both OP9 and OP9DL1 showed increased nitrate oxide (NO) production. The NO levels of OP9 were higher than that of OP9DL1 when stimulated with TNFα/IFNγ or LPS/IL4. Taken together, our study reveals a previously unrecognized role of OP9 and OP9DL1 in mature B and T cell proliferation. DL1 overexpression alone changed the properties of OP9 cells in addition to their role in early B cell development.

Selective solid-phase extraction of artificial chemicals from milk samples using multiple-template surface molecularly imprinted polymers.

A novel multiple-template surface molecularly imprinted polymer (MTMIP) was synthesized using ofloxacin and 17ß-estradiol as templates and modified monodispersed poly(glycidylmethacrylate-co-ethylene dimethacrylate) (PGMA/EDMA ) beads as the support material. Static adsorption, solid-phase extraction and high-performance liquid chromatography were performed to investigate the adsorption properties and selective recognition characteristics of the polymer templates and their structural analogs. The maximum binding capacities of ofloxacin and 17ß-estradiol on the MTMIP were 9.0 and 6.6 mg/g, respectively. Compared with the corresponding nonimprinted polymer, the MTMIP exhibited a much higher adsorption performance and selectivity toward three quinolones and three estrogens, which are common drug residues in food. The MTMIP served as a simple and effective pretreatment method and could be successfully applied to the simultaneous analysis of multiple target components in complex samples. Furthermore, the MTMIP may find useful applications as a solid-phase absorbent in the simultaneous determination of trace quinolones and estrogens in milk samples, as the recoveries were in the range 77.6-98.0%.

Preparation of poly(vinylphenylboronic acid) chain grafted poly(glycidylmethacrylate-co-ethylenedimethacrylate) beads for the selective enrichment of glycoprotein.

Surface-initiated atom transfer radical polymerization was successfully used to prepare 4-vinylphenylboronic acid functionalized poly(glycidylmethacrylate-co-ethylenedimethacrylate) beads for the selective enrichment of glycoprotein from complex biological samples in this study. The modified bead surfaces were characterized using Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy. The sorption behaviors, including adsorption isotherms, incubation time, and pH effect, were investigated. The results demonstrated that the boronated beads have a high affinity for glycoprotein, which is due to the well-defined boronic acid brushes on the beads surfaces. Furthermore, the polyvinylphenylboronic acid grafted poly(glycidylmethacrylate-co-ethylenedimethacrylate) beads were used to efficiently enrich and purify glycoprotein from real egg white samples and α-fetoprotein from human serum samples. The mass spectrometry results demonstrated that the polyvinylphenylboronic acid grafted poly(glycidylmethacrylate-co-ethylenedimethacrylate) beads are a suitable material for the enrichment of glycosylated protein from complex biological samples.

[Effects of reduced solar radiation on winter wheat flag leaf net photosynthetic rate].

Taking winter wheat Triticum aestivum L. (cv. Yangmai 13) as test material, a field experiment was conducted in Nanjing City to study the effects of simulated reduced solar radiation on the diurnal variation of winter wheat flag leaf photosynthetic rate and the main affecting factors. Five treatments were installed, i. e., 15% (T15), 20% (T20) , 40% (T40), 60% (T60), and 100% (CK) of total incident solar radiation. Reduced solar irradiance increased the chlorophyll and lutein contents significantly, but decreased the net photosynthetic rate (Pn). Under different solar irradiance, the diurnal variation of Pn had greater difference, and the daily maximum Pn was in the order of CK > T60 > T40 > T 20 > T15. In CK, the Pn exhibited a double peak diurnal curve; while in the other four treatments, the Pn showed a single peak curve, and the peak was lagged behind that of CK. Correlation analysis showed that reduced solar irradiance was the main factor affecting the diurnal variation of Pn, but the physiological parameters also played important roles in determining the diurnal variation of Pn. In treatments T60 and T40, the photosynthesis active radiation (PAR), leaf temperature (T1) , stomatal conductance (Gs) , and transpiration rate (Tr) were significantly positively correlated with Pn, suggesting their positive effects on Pn. The intercellular CO2 concentration (Ci) and stomatal limitation (Ls) had significant negative correlations with Pn in treatments T60 and T40 but significant positive correlations with Pn in treatments T20 and T15, implying that the Ci and Ls had negative (or positive) effects on Pn when the solar irradiance was higher (or lower) than 40% of incident solar irradiance.