In situ spectral imaging of marker proteins in gastric cancer with near-infrared and visible quantum dots probes

This study presents the investigation of bioconjugating ability of near-infrared (NIR) CdSeTe/ZnS quantum dots (QDs) (710 nm) and visible CdSe QDs (595 nm) in immunofluorescent staining for cancer biomarkers in gastric cancer tissues probed with the homemade Hadamard transform (HT) spectral imaging microscope and a commercial multispectral imaging system. The results show that imunostaining ability of NIR QDs probes is stronger than that of visible QDs when the two kinds of QDs are simultaneously used to probe the cancer biomarkers such as cytokeratin 20 (CK20) and proliferating cell nuclear antigen (PCNA) in gastric cancer tissues. Moreover, when the two QDs probes are used for immunostaining successively for the same target molecules, staining order has great influences on the final results due to their different conjugating ability to the marker proteins. The results imply that NIR QDs hold more promise for real-time imaging of tumor tissues due to its higher sensitivity and contrast. In addition, the results also demonstrate the potential of Hadamard transform spectral imaging as a useful tool in biomedical analysis and quantitative evaluation for tumor tissues.     

High Levels of Expression of Fibroblast Growth Factor 21 in Transgenic Tobacco (<Emphasis Type="Italic">Nicotiana benthamiana)</Emphasis>

Fibroblast growth factor-21 (FGF21) is a hepatic hormone that plays a critical role in metabolism, stimulating fatty acid oxidation in the liver and glucose uptake in adipose tissue. In this study, we produced tobacco plants expressing human recombinant FGF21 (hFGF21) via Agrobacterium-mediated transformation using a potato virus X (PVX)-based vector (pgR107). The vector contained the sequence encoding the human FGF21 gene fused with green florescence protein and a histidine tag. The recombinant plasmid was introduced into leaf cells of Nicotiana benthamiana (a wild Australian tobacco) via Agrobacterium-mediated agroinfiltration. As determined by fluorescence and Western blot of leaf extracts, the hFGF21 gene was correctly translated in tobacco plants. Seven days after agroinfection, the recombinant hFGF21 had accumulated to levels as high as 450 μg g⁻¹ fresh weight in leaves of agroinfected plants. The recombinant hFGF21 was purified from plant tissues by Ni–NTA affinity chromatography, and the purified hFGF21 stimulated glucose uptake in 3T3/L1 cells. This indicated that the recombinant hFGF21 expressed via the PVX viral vector in N. benthamiana was biologically active.     

Aggregation-induced emission of tetraphenylethene derivative as a fluorescence method for probing the assembling/disassembling of amphiphilic molecules

The aggregation-induced emission (AIE) of a 1,2-diphenyl-1,2-di(p-tolyl)ethene (TPE) was explored as a novel fluorescence method for probing the assembling/disassembling of amphiphilic molecules. The fluorescence intensity was able to monitor the formation of micelles and determine the critical micelle concentration (CMC) of surfactants. The temperature-dependent micellization of the pharmaceutically important PEO-PPO-PEO copolymer, Pluronic F127, was further studied by using the TPE fluorescence spectrum intensity. Our results showed good agreement with those reported in the literature by using other methods. The special advantage of the AIE probe method was further explored to determine the assembling/disassembling process of the colored amphiphilic molecule, 1-[4-(3-phenylazophenoxy)butyl]triethylamine bromide (AzoC4), whose CMC value has not previously been described. Since the TPE fluorescence signal mainly comes from the aqueous phase, not from the inside of hydrophobic core, it provides a possible platform to study the CMC of those colored surfactants. Based on the novel fluorescence properties of TPE in the aggregated and dispersed states, one can conclude that the TPE method is a promising method for the determination of the CMC and critical micellization temperature (CMT), particularly having a special advantage to determine the assembling/disassembling process of colored amphiphilic molecules.     

反相离子对色谱-电感耦合等离子体质谱法测定化妆品中不同形态的铬

建立了反相离子对色谱(RP-IPC)与电感耦合等离子体质谱(ICP-MS)联用技术快速分离测定化妆品中Cr(III)和Cr(VI)的方法。样品经乙二胺四乙酸钠盐(EDTA)50 ℃水浴中提取后,采用XDB-C18色谱柱分离,以5%(v/v)甲醇-2.0 mmol/L四正丁基铵盐(TBA)水溶液(pH 6.0)作为流动相,流速为1.0 mL/min,进样量为100 μL。采用碰撞池技术消除ICP-MS测定时40Ar12C+、35Cl16O1H+对52Cr+的光谱学干扰。Cr(III)和Cr(VI)的分离过程在5 min内完成。样品中加标量为0.01～0.50 μg时,其回收率为82.7%～107.2%,相对标准偏差(RSD)小于5.62%。该方法操作简便、灵敏度高、重现性好,适合于化妆品中Cr(III)和Cr(VI)的同时分析。     

DFT study on the selective oxidation of vinyl chloride on different metal surfaces

Selective epoxidation of vinyl chloride on Ag(111), Pt(111) and Rh(111) with pre-adsorbed atomic oxygen has been studied by density functional theory (DFT) calculation with the periodic slab model. The reaction energies and activation energies of the epoxidation reaction are determined. Because of the asymmetry of vinyl chloride, three competitive reaction pathways are investigated. The results indicate that the most possible reaction pathway is pathway III. Compared the activation energies of the epoxidation reaction on Ag(111), Pt(111) and Rh(111), it is obvious that the reaction via OMMC(3) on Ag(111) is the most possible process. However, the selectivity to the target product over Ag(111) is the lowest among the three metals. The results also indicate that the formation of chloroacetaldehyde is more favorable than that of chloroepoxide.     

A new carotenoid glycoside from Rehmannia glutinosa

A new carotenoid glycoside, namely neo-rehmannioside (1), together with five known compounds, 6-O-seco-hydroxyaeginetoyl ajugol (2), oxyrehmaionoside B (3), ajugol (4), geniposidic acid (5) and geniposide (6) was isolated from the 95% ethanol extract of dry roots of Rehmannia glutinosa. The structure of the new compound (1) was determined based on MS, IR, 1-D and 2-D NMR spectral data.     

Liquid chromatography/mass spectrometry-based metabolic profiling to elucidate chemical differences of tobacco leaves between Zimbabwe and China

An approach was developed for extracting and analyzing the chemical components of tobacco leaves based on solvent extraction and rapid & resolution liquid chromatography/quadrupole time-of-flight mass spectrometry analysis. Two solvents with different polarities were used to extract hydrophilic components and hydrophobic components, respectively, the combined analytical data can provide a "global" view of metabolites. Based on the evaluation of parallel samples, it was found that this approach provided good repeatability, accurate and reliable profiling data, and is suitable for the metabolomics study of tobacco leaves. In order to find the chemical component differences of tobacco leaves, 56 samples from Zimbabwe and China were analyzed using the developed method. The metabolite data were processed by multivariate statistic technique; an obvious group classification between Zimbabwe and China was observed, 14 significantly changed compounds were found, and 9 of them were identified.     

Gas chromatography-mass spectrometric method for metabolic profiling of tobacco leaves

A gas chromatography-mass spectrometric method was developed for profiling of tobacco leaves. The differentiation among tobacco leaves planted in two different regions was investigated. Prior to analysis, the extraction solvent formulation was optimized and a combination of water, methanol and acetonitrile with a volume ratio of 3:1:1 was found to be optimal. The reproducibility of the method was satisfactory. Kendall tau-b rank correlation coefficients were equal to 1 (p<0.05) for 82% of the resolved peaks (up to 95% of the overall peak areas), indicating the good response correlation. Forty-four compounds including 9 saccharides, 9 alcohols, 9 amino acids, 16 organic acids and phosphoric acid were identified based on standard compounds. The method was successfully applied for profiling of tobacco leaves from Zimbabwe and Yunnan of China. Our result revealed that levels of saccharides and their derivatives including xylose, ribose, fructose, glucose, turanose, xylitol and glyceric acid were more abundant while sucrose, glucitol and D-gluconic acid were less abundant in tobacco leaves from Yunnan as compared to those from Zimbabwe. Amino acids such as L-alanine, L-tyrosine and L-threonine were found to be richer in Zimbabwe tobacco than in Yunnan tobacco.     

Micelles from amphiphilic block copolyphosphates for drug delivery

Amphiphilic block copolyphosphates (PEP-b-PIPPs) are synthesized by two-step ROP of cyclic phosphate monomers with different pedant groups. They can spontaneously self-assemble into approximately spherical micelles ranging in size between 89 and 198 nm in water. A typical hydrophobic anti-cancer drug DOX is encapsulated into the micelles. The release rate of DOX slows down with increasing hydrophobic block length of PIPP. DOX-loaded micelles are investigated for the proliferation inhibition of Hela cells and the DOX dose required for 50% cellular growth inhibition is found to be 0.8 μg mL(-1). It is demonstrated that PEP-b-PIPP micelles can be used as a safe and promising drug delivery system.