Highly Efficient and Enzymatic Regioselective Undecylenoylation of Gastrodin in 2-Methyltetrahydrofuran-Containing Systems

Highly efficient and regioselective acylation of pharmacologically interesting gastrodin with vinyl undecylenic acid has been firstly performed through an enzymatic approach. The highest catalytic activity and regioselectivity towards the acylation of 7′-hydroxyl of gastrodin was obtained with Pseudomonas cepacia lipase. In addition, it was observed the lipase displayed higher activity in the eco-friendly solvent 2-methyltetrahydrofuran-containing systems than in other organic solvents. In the co-solvent mixture of tetrahydrofuran and 2-methyltetrahydrofuran (3/1, v/v), the reaction rate was 60.6 mM/h, substrate conversion exceeded 99%, and 7′-regioselectivity was 93%. It was also interesting that the lipase-catalyzed acylation couldn’t be influenced by the benzylic alcohol in gastrodin. However, pseudomonas cepacia lipase displayed different regioselectivity towards gastrodin and arbutin.     

A Simple and Sensitive Approach for Ochratoxin A Detection Using a Label-Free Fluorescent Aptasensor

Ochratoxin A(OTA) is found to be one of the predominant contaminating mycotoxins in a wide variety of food commodities. To avoid the risk of OTA consumption, the detection and quantitation of OTA level are of great significance. Based on the fact that ssDNA aptamer has the ability to form a double-strand structure with its complementary sequence, a simple and rapid aptamer-based label-free approach for highly sensitive and selective fluorescence detection of OTA was developed by using ultra-sensitive double-strand DNA specific dyes PicoGreen. The results showed that as low as 1 ng/mL of OTA could be detected with a dynamic range of more than 5 orders of magnitude which satisfies the requirements for OTA maximum residue limit in various food regulated by European Commission. With the specificity of aptamer, the assay exhibited high selectivity for OTA against two other analogues (N-acetyl-l-phenylalanine and zearalenone). We also tested the aptasensor practicability using real sample of 1% beer spiked with a series of concentration of OTA and the results show good tolerance to matrix effect. All detections could be achieved in less than 30 min, which provides a simple, quick and sensitive detection method for OTA screening in food safety and could be easily extend to other small molecular chemical compounds detection which aptamer has been selected.     

生态系统完整性在管理层面的体现方式: 以跨省国家公园统一管理的体制机制为例

生态系统完整性保护是国家公园的重要管理目标, 但学术上的完整性如何体现为管理上的完整性需要基于科学概念进行体制设计。从管理层面体现生态系统完整性需要突破原有的属地化要素管理模式, 把国家公园作为国土空间用途管制的独立单元, 将“山水林田湖草”统筹起来一体化管理, 但这种管理往往因为不同行政区不同的“权、钱”相关制度引发的激励不相容而难以实现, 尤其在国家公园跨省的情况下。可以首先实现跨省国家公园不同省的管理机构“权、钱”相关制度统一, 再构建协调机制或组建类似资产管理的协调机构, 以实现激励相容。在这样的体制机制下, 今后的国家公园划界也易于突破省界藩篱, 更好体现科学概念上的完整性。     

A dicyclic-type electrode-based biofilm reactor for simultaneous nitrate and Cr(VI) reduction

Bioprocess and Biosystems Engineering - A dicyclic-type electrode-based biofilm-electrode reactor (BER) was investigated for simultaneous removal of nitrate and Cr(VI). In the absence of Cr(VI),...     

地塞米松对小鼠肠道菌群及脏器的影响

目的应用聚合酶链式反应-变性梯度凝胶电泳(PCR-DGGE)技术及苏木精-伊红染色法(HE染色法)探究地塞米松对小鼠肠道菌群和脏器的影响。方法选用SPF级Balb/c小鼠10只,随机分为实验组和对照组,每组5只。实验组每日灌胃1.228 5 mg/kg地塞米松,对照组不做任何处理。观察小鼠体质量、行为、皮毛和粪便等的变化。28 d后,无菌条件下取小鼠粪便提取细菌基因组DNA,应用PCR-DGGE技术进行肠道菌群多样性及差异性分析;取小鼠肺、脾、肝、小肠、盲肠等进行HE染色,观察其脏器变化情况。结果与对照组相比,实验组小鼠体质量有明显降低,肺指数升高,脾指数下降;PCR-DGGE结果表明实验组小鼠肠道菌群的多样性明显增加,优势菌群发生转变;实验组小鼠脏器出现了明显的炎症反应。结论服用地塞米松使小鼠肠道菌群的构成和多样性发生了显著改变;引起了小鼠脏器的炎症反应,可能会对小鼠生长发育产生影响。     

Apatinib attenuates phenotypic switching of arterial smooth muscle cells in vascular remodelling by targeting the PDGF Receptor‐β

Apatinib (YN968D1) is a small‐molecule tyrosine kinase inhibitor（TKI）which can inhibit the activity of vascular endothelial growth factor receptor‐2 (VEGFR‐2). It has been reported that apatinib has anti‐tumour effect of inhibiting proliferation and inducing apoptosis of a variety of solid tumour cells, whereas its effect on vascular smooth muscle cells (VSMC) remains unclear. This study investigated the effect of apatinib on phenotypic switching of arterial smooth muscle cells in vascular remodelling. Compared to the vehicle groups, mice that were performed carotid artery ligation injury and treated with apatinib produced a reduction in abnormal neointimal area. For in vitro experiment, apatinib administration inhibited VSMC proliferation, migration and reversed VSMC dedifferentiation with the stimulation of platelet‐derived growth factor type BB (PDGF‐BB).In terms of mechanism, with the preincubation of apatinib, the activations of PDGF receptor‐β (PDGFR‐β) and phosphoinositide‐specific phospholipase C‐γ1 (PLC‐γ1) induced by PDGF‐BB were inhibited in VSMCs. With the preincubation of apatinib, the phosphorylation of PDGFR‐β, extracellular signal‐related kinases (ERK1/2) and Jun amino‐terminal kinases (JNK) induced by PDGF‐BB were also inhibited in rat vascular smooth muscle cell line A7r5. Herein, we found that apatinib attenuates phenotypic switching of arterial smooth muscle cells induced by PDGF‐BB in vitro and vascular remodelling in vivo. Therefore, apatinib is a potential candidate to treat vascular proliferative diseases.     

Intestinal absorption and first-pass metabolism of polyphenol compounds in rat and their transport dynamics in Caco-2 cells

Background

Polyphenols, a group of complex naturally occurring compounds, are widely distributed throughout the plant kingdom and are therefore readily consumed by humans. The relationship between their chemical structure and intestinal absorption, transport, and first-pass metabolism remains unresolved, however.

Methods

Here, we investigated the intestinal absorption and first-pass metabolism of four polyphenol compounds, apigenin, resveratrol, emodin and chrysophanol, using the in vitro Caco-2 cell monolayer model system and in situ intestinal perfusion and in vivo pharmacokinetic studies in rats, so as to better understand the relationship between the chemical structure and biological fate of the dietary polyphenols.

Conclusion

After oral administration, emodin and chrysophanol exhibited different absorptive and metabolic behaviours compared to apigenin and resveratrol. The differences in their chemical structures presumably resulted in differing affinities for drug-metabolizing enzymes, such as glucuronidase and sulphatase, and transporters, such as MRP2, SGLT1, and P-glycoprotein, which are found in intestinal epithelial cells.