Search

An intentional or inadvertent mixing of plant materials containing ephedrine alkaloids, especially Ephedra, is illegal. In order to better detect plant materials containing ephedrine alkaloids in export and smuggling, DNA barcoding combined with a TaqMan real-time PCR-based assay were used in this study. We collected 201 samples from 18 species belonging to four genera distributed in three families to amplify two barcoding markers, internal transcribed spacer 2 (ITS2) and psbA-trnH. 175 ITS2 sequences and 136 psbA-trnH sequences were obtained. Alignments and the neighbor-joining tree indicated that ITS2 showed a better discrimination of species than psbA-trnH. In addition, based on the sequence comparison of the ITS2 region from 18 species, three sets of primer/probes were designed using the real-time PCR assay platform. A sensitivity test showed the above primer/probe sets were specific and sensitive (as little as 0.0050 ng/μL target DNA) to identify species containing ephedrine alkaloids. Hence, the combination of novel DNA barcoding and the TaqMan real-time PCR-based technique are promising tools for the identification of plant materials containing ephedrine alkaloids. It is beneficial to standardize market circulation and detection of plant materials containing ephedrine alkaloids.

This present study investigated detoxification mechanisms of leguminous forage Trifolium pratense L. (red clover) seedlings upon exposure to Ag ions (Ag+) on an atomic level. Depressed plant growth (maximum inhibition rate: 46.57%) and significantly altered antioxidase/antioxidant substances levels (maximum inhibition rate: 65.45%/55.41%) revealed that the physiological metabolism was disturbed. Notable lesions were observed in both leaf and root cells at 588 μM Ag+ treatment. All differentially expressed genes (DEGs) were remarkably mapped to biological metabolism related pathways. Red clover seedlings were speculated to initially transform and immobilize Ag+ in the culture medium, then transporting and fixing them inside the cell, mainly as unreduced Ag+ bound to oxygen-, nitrogen-, sulfur-, chloride-containing biological molecules. A portion of Ag+ was reduced to Ag0 and aggregated to form crystalline argentiferous nanoparticles. Effective reducing agents such as alcohols, carboxylic acid, and etc, which are capable of coordinating heavy metals to reduce and stabilize them, were assumed to play a role in Ag+ reduction. The research results are of great value to understand the defense and tolerance mechanisms of red clover to Ag+ and explore the main existing forms of Ag+ in vivo and in vitro, which could indicate contamination condition in regional ecological environment such as mining area and its potential effects.

Succinic acid is an important platform chemical that can be used to produce a broad range of compounds with extensive applications. By applying rational metabolic engineering, we had previously developed a series of innovative succinic acid-producing Yarrowia lipolytica strains that could produce succinic acid effectively using glycerol. In the present study, glucose was used for succinic acid production by these engineered strains, without pH control. Strain PGC11505, in which the gene (YlACH1) of acetyl-CoA hydrolase corresponding for acetic acid overflow was deleted, exhibited the ability to utilize glucose for succinic acid production efficiently. Strain PGC202, with a strengthened reductive carboxylation and oxidative tricarboxylic acid cycle by overexpression of ScPCK and endogenous YlSCS2, yielded 23.8 g/L succinic acid. After fermentation optimization, the succinic acid titer reached to 32.6 g/L in flask cultures. In a bench-top fermenter, this strain produced 53.6 g/L succinic acid with a yield of 0.61 g/g-glucose without pH control. In conclusion, through rational metabolic engineering of Y. lipolytica, we have successfully achieved the high-yield production of succinic acid using glucose as the sole carbon source under natural low pH condition. This new Y. lipolytica strain would be highly useful in industrial processes for the production of succinic acid using low-cost glucose.

Allicin is a natural effective organosulfur compound isolated from garlic, which possesses many beneficial properties, such as antibacterial, anti-inflammatory, antimicrobial, hypotensive and hypolipidemic. In the present study, we investigated the effects and the underlying mechanisms of allicin on isolated mesenteric arteries (MAs). We examined MAs relaxation induced by allicin on rat-isolated mesenteric artery (MA) rings, the KATP channels with patch, and the expression of Kir6.1 and SUR2B with western blotting and NO production with Diaminofluorescein-FM diacetate (DAF-FMDA) in rat mesenteric artery smooth muscle cells (MASMCs). The results showed that allicin elicited the dose-dependent vasorelaxation effect with phenylephrine (PE) precontracted rat MA rings. The vasorelaxation effect was endothelium and NO independent but could be diminished by inhibition of PKA and KATP channels in the vascular smooth muscle. Allicin activated KATP channels in rat MASMCs, and the activation of KATP channels was inhibited by the inhibitors of PKA and KATP channels. But allicin had no effect on the expression of KATP subtypes Kir6.1 and SUR2B. These observations suggest that allicin exerts vasorelaxation effect through activation of PKA-KATP-signaling pathway.

The aim of the study was to investigate the effects of protosappanin B on the proliferation and apoptosis of bladder cancer cells. The effects of protosappanin B (12.5, 25, 50, 100, or 200 μg/mL, 48 h) on proliferation of SV-HUC-1, T24 and 5637 cells was assessed using the MTT assay. The effects of protosappanin B (100, 150, 200, 250, or 300 μg/mL, 48 h) on cell apoptosis and cell cycle were analyzed using flow cytometry. T24 and 5637 cells treated with 200 µg/mL protosappanin B showed morphological changes (shrinkage, rounding, membrane abnormalities, and reduced adhesion), but protosappanin B had no proliferation arrest effect on SV-HUC-1 cells. Protosappanin B caused concentration-dependent inhibition of cell growth, with IC50 of 82.78 µg/mL in T24 cells and 113.79 µg/mL in 5637 cells. Protosappanin B caused concentration-dependent increases in T24 and 5637 cell apoptosis (100–300 µg/mL). The effects of protosappanin B on the cell cycle in both cell types was G1 arrest with reductions in the proportion of S-phase cells and proliferation index. A proteomics analysis showed that protosappanin B modulated a number of genes involved in the cell cycle. In conclusion, protosappanin B inhibits the proliferation and promotes the apoptosis of T24 and 5637 human bladder cancer cells in a concentration-dependent manner, possibly via interference with cell cycle regulation, preventing G1-to-S transition.

Aims: Nobiletin, a natural polymethoxylated flavonoid compound, has various beneficial properties, such as anticancer, anti-inflammatory, and antioxidant effects, and it also improves memory. Therefore, we investigated the effects and mechanisms of nobiletin on rat isolated mesenteric arteries (MAs). Methods: We examined vasodilation induced by nobiletin on rat isolated MA rings with a tension study, the expression and activity of endothelial nitric oxide synthase (eNOS) with Western blotting, NO production with DAF- FMDA fluorescence, and intracellular Ca2+ concentration ([Ca2+]i) with Fluo-3AM. Results and Conclusion: Our study showed that nobiletin elicited a dose-dependent vasodilation in phenylephrine precontracted MA rings, but it did not elicit the same response in pulmonary artery rings. Vasodilation was related to endothelium and activated partly by eNOS. Vasodilation was inhibited by denudation of the endothelium or inhibition of eNOS activity. Nobiletin increased NO production by promoting the phosphorylation of eNOS at Ser-1177 without changing the level of eNOS expression in rat mesenteric artery endothelial cells (RMAECs). Nobiletin increased the concentration of endothelial [Ca2+]i, which enhances eNOS activity in RMAECs. In summary, vasodilation induced by nobiletin was dependent on the endothelium and partly on eNOS activation, which is mediated by high endothelial [Ca2+]i. Results suggest nobiletin may offer a therapeutic benefit and could potentially be used as a vasodilator for the treatment of hypertension.

Pulmonary arterial hypertension (PAH) is a severe cardiovascular disease that can lead to vascular remodelling and hypertension. Clinical diagnosis of PAH is very difficult. Uric acid (UA) can act as a biological marker for screening of PAH in patients. Multiple studies have indicated that reactive oxygen species (ROS) play an important role in the development of PAH. Thus, it is important to study the relationship between UA and ROS based on the pathogenesis of PAH. For monitoring PAH, a high performance liquid chromatography-electrospray ionization-tandem mass spectrometry (HPLC-ESI-MS/MS) method was developed to measure the concentration of UA from rat models and pulmonary arterial endothelial cells (PAECs) models, which were induced by monocrotaline (MCT) and hypoxia, respectively. In addition, the treatment groups were treated by N-acetyl-L-cysteine (NAC), a ROS scavenger. With the confirmation from hematoxylin-eosin (H&E) staining, the HPLC-ESI-MS/MS method was adopted to successfully analyze the concentration of UA. In this study, for the first time, thymine was used as an internal standard (I.S.) of uric acid. The results showed that the UA concentration in the PAH groups was higher than that in the normal groups, while the UA concentration in the treatment groups decreased compared to that in the PAH group (p < 0.05). It was experimentally proven that the HPLC-ESI-MS/MS method is a rapid, efficient and reliable quantitative method to detect PAH. Furthermore, our results indicated that UA and ROS have a double-regulator role.

Adsorption isotherm and thermal transition of yacon dried by combined heat pump and microwave method were developed to investigate the interactions between water and biopolymers. Adsorption isotherm of yacon was determined by the gravimetric method, and the data were modeled by GAB model. The GAB monolayer moisture content was observed to be 0.0795 g H2O g−1 dry solids. Thermal transitions of yacon powders equilibrated at various water activities were analyzed using differential scanning calorimetry. The state diagram was developed using glass transition line and freezing curve, which were modeled by Gordon–Taylor equation and Clausius–Clapeyron equation, respectively. The maximal-freeze-concentrated condition was estimated as the solid content of 0.706 g g−1 yacon with the glass transition temperature of −66.6 °C. The adsorption properties and state diagram of yacon are useful in optimizing conditions of freezing and drying of yacon as well as in evaluating its storage stability as a function of moisture content and temperature.

Response surface methodology was employed to investigate the effects of drying temperature (15.0–45.0C), air velocity (1.00–2.00 m/s), moisture content at conversion point (40.0–60.0%) and microwave (MW) power (1.0–3.0 W/g) on the average drying rate (DR), specific moisture evaporation rate (SMER), total color difference (ΔE), rehydration ratio (RR) and shrinkage ratio (SR) of yacon dried by combined heat pump (HP) and MW methods. A central composite rotatable design was used to develop models for responses. The coefficients of determination R2 of DR, SMER and ΔE were higher than 0.7. However, R2 of RR and SR were 0.540 and 0.343, respectively. Based on response surface and desirability functions, the optimum conditions for combined HP and MW drying of yacon were drying temperature of 42.7C, air velocity of 1.69 m/s, moisture content at conversion point of 50% and MW power of 2.0 W/g. At this optimum point, DR, SMER and ΔE were 0.262 kgH2O/kg(d.b.)·h, 0.222 kg/kW·h and 23.59, respectively. Practical Applications Yacon are rich in essential amino acids, minerals and fructooligosaccharides (FOS). However, FOS hydrolyzation, browning and decay are the common phenomena during postharvest storage and transportation. Hybrid drying techniques are being developed to minimize weakness and maximize merits of different drying techniques to produce better quality of foodstuffs, reduce drying time, decrease energy consumption and increase drying efficiency. Therefore, response surface methodology was employed to investigate the effects of drying temperature, air velocity, moisture content at conversion point and MW power on the average DR, SMER, ΔE, RR and SR of yacon dried by combined HP and MW methods, and the optimum process conditions were determined to obtain the criteria of maximum DR and SMER, and minimum ΔE. This research will provide valuable information for industrialization of yacon dried by combined HP and MW methods.

Heat pump drying kinetics and quality characteristics of yacon at different drying temperatures (5, 15, 25, 35 and 45 °C) and air velocities (0.5, 1.0, 1.5 and 2.0 m/s) were investigated. Results indicated that drying took place in the falling rate period. The drying temperature and air velocity had a significant effect on drying behavior of yacon slices. Drying time decreased with increasing drying temperature and air velocity. Eight mathematical models were selected to describe and compare the drying kinetics of yacon. Comparisons were based on the coefficient of determination ( R 2 ), reduced chi-square ( χ 2 ) and root mean square error (RMSE). Among the models tested, the Midilli et al. model achieved the best fit. Moisture transfer from yacon slice was described by applying the Fick’s diffusion model. Effective diffusivity coefficients ( D eff ) increased with increasing drying temperature and were found to range from 1.092 to 7.388 × 10 −7 m 2 /s. The temperature dependence of the effective diffusivity was described by the Arrhenius-type relationship and the activation energy for the diffusion of the moisture associated with the yacon was found to be 30.00 kJ/mol. Drying temperature and air velocity had little effects ( p > 0.05) on the total color difference, shrinkage rate and rehydration rate of dried yacon slcies.

Moisture adsorption isotherms of Agaricus bisporus were determined at different temperatures (5, 15, 25 and 35C) using a static gravimetric method. Several saturated salt solutions were prepared to obtain different water activities in the range of 0.11–0.93. Freeze-dried A. bisporus was equilibrated with designed saturated salt solutions. For certain water activity, the equilibrium moisture contents of A. bisporus decreased with increasing temperature. Adsorption isotherms of freeze-dried A. bisporus followed type III isotherm, which is typical for polysaccharide products. Nine models were used to fit experimental data by linear regression analysis method to ascertain the best of fit. Comparisons were based on mean relative percent error (E), standard error (SE), coefficient of correlation (R2) and residual plots. Among the models tested, the Halsey model achieved the best fit. Based on Clausius–Clapeyron equation, the net isosteric adsorption heat of A. bisporus decreased from 12.12 to 0.30 kJ/mol when the moisture content increased from 8 to 50 g/100 g dry matter. PRACTICAL APPLICATIONS A. bisporus's shelf life is only 1–3 days at ambient temperature. Drying, especially freeze-drying, is one of the main preservation methods for A. bisporus. Developing moisture sorption isotherms (MSIs) for A. bisporus could provide essential information about optimizing its drying process and storage conditions. In addition, isosteric heat of sorption in dehydrated and intermediate moisture food also plays an important role in modeling of various food processing and storage. Optimization of drying process and storage conditions of dried A. bisporus could be obtained by developing its MSI.

We attempted to introduce phytic acid as a binder to construct the controllable structure. Phytic acid and Au NPs were assembled by layer-by-layer onto the surface of gold electrode to forming the three-dimensional mesoporous Au interface. And then high sensitive HRP biosensor was prepared based on the proposed mesoporous interface. Surface Enhanced Raman Scattering and electrochemical impedance are applied to characterizing the process of forming nano film. The resulting biosensor responses to H2O2 were linearly proportional to the concentrations from 2.5×10-5 ~1.0×10-4 mol L-1as well as 1×10-4 ~ 4×10-3 mol L-1 with a detection limit of 8.6×10-6 mol L-1 (S/N = 3).