Design and Synthesis of Fluoroacylshikonin as an Anticancer Agent

A series of shikonin derivatives, selectively acylated by various fluorinated carboxylic acids at the side chain of shikonin, were synthesized and their anticancer activity evaluated, in which eight compounds are reported for the first time. Among all the compounds tested, compound S7 showed the most potent anticancer activity against B16‐F10 (malignant melanoma cells), MG63 (human osteosarcoma cells), and A549 (lung cancer cells) with IC₅₀ 0.39 ± 0.01, 0.72 ± 0.04 and 0.58 ± 0.02 µmol/L. Docking simulation of compound S7 was carried out to position S7 into a tubulin active site to determine the probable binding conformation. All the results suggested that compound S7 may be a potential anticancer agent. Chirality 25:757–762, 2013. © 2013 Wiley Periodicals, Inc.     

大豆转录因子GmERF5的克隆、表达及功能分析

ERF转录因子是植物中特有的转录因子家族之一, 在植物响应生物和非生物胁迫过程中发挥重要的调控作用。通过对大豆(Glycine max)吉林32未成熟胚的表达谱分析, 利用RT-PCR技术从大豆中克隆了1个新的ERF转录因子GmERF5。GmERF5具有237个氨基酸残基, 分子量为26.09 kDa, 等电点为6.85, 其开放阅读框长714 bp。该转录因子蛋白与Gh-ERF2蛋白的同源性最高, 它们同属ERF亚家族的第IV亚类。实时荧光定量PCR分析表明, 该蛋白基因在大豆的根中表达量最高, 且受干旱、高盐、低温及乙烯、脱落酸和茉莉酸甲酯的诱导上调表达。亚细胞定位实验结果表明, GmERF5蛋白定位于细胞核中。转录激活能力分析结果显示, GmERF5可以激活报告基因的表达, 为转录激活子。综合以上结果, 认为GmERF5可能作为转录调控因子参与大豆生物和非生物胁迫的应答。     

脯氨酸转运相关基因的研究进展

作为植物中普遍存在的一种逆境适应机制, 脯氨酸积累一直被认为是其合成和降解调控的结果。然而越来越多的研究表明, 脯氨酸转运也可能在其积累过程中起重要作用。在植物中, 有多个氨基酸转运蛋白家族, 如氨基酸通透酶家族(AAPs)、赖氨酸组氨酸转运蛋白家族(LHTs)和脯氨酸转运蛋白家族(ProTs)参与脯氨酸在各个器官间的运输。该文对参与脯氨酸运输的基因家族成员的表达模式、生理功能及表达调控进行了综述, 以期为脯氨酸运输与积累在植物抗逆方面的研究提供参考。     

Fluorescence spectroscopy and docking study in two flavonoids,isolated tectoridin and its aglycone tectorigenin,interacting with human serum albumin: a comparison study

Two flavonoids, tectoridin (TD) isolated from rhizomes of Iris tectorum and hydrolyzed aglycone tectorigenin (TG) were prepared and characterized to compare their different interaction ability with human serum albumin (HSA). Based on the results, the affinity of TG–HSA was stronger than that of TD–HAS, and TG combined more closely with HSA than did TD. HSA fluorescence was quenched by TD/TG. The interactions between TD/TG and HSA involved static quenching. The thermodynamic parameters indicated that both binding processes were spontaneous; hydrogen binding and van der Waals force were the main forces between TD and HSA, whereas a hydrophobic interaction was the main binding force between TG and HSA. Synchronous and 3D fluorescence spectra showed that the binding of TD/TG to HSA induced conformational changes. Moreover, a docking study confirmed the experimental results. Copyright © 2015 John Wiley & Sons, Ltd.     

Diagnostic Evaluation of Des-Gamma-Carboxy Prothrombin versus α-Fetoprotein for Hepatitis B Virus-Related Hepatocellular Carcinoma in China: A Large-Scale,Multicentre Study

An efficient serum marker for hepatocellular carcinoma (HCC) is currently lacking and requires intensive exploration. We aimed to evaluate the performance of des-gamma-carboxy prothrombin (DCP) for identifying hepatitis B virus-related HCC in a large, multicentre study in China. A total of 1034 subjects in three cohorts (A, B, and C) including HCC and various non-HCC controls were enrolled from 4 academic medical centers in China from January 2011 to February 2014. Blind parallel detections were conducted for DCP and AFP. The area under the receiver operating characteristic curve (AUC) was used to evaluate the diagnostic efficacies. In cohort A, which comprised 521 subjects, including patients with HCC, liver metastasis, liver cirrhosis (LC), and liver hemangiomas as well as healthy controls (HCs), the accuracy of DCP for distinguishing HCC from various controls was 6.2–9.7% higher than that of AFP. In cohort B, which comprised 447 subjects, including patients with HCC, LC, and chronic hepatitis B as well as HC, the accuracy of DCP was further elevated (12.3–20.67% higher than that of AFP). The superiority of DCP to AFP was more profound in the surveillance of early HCC [AUC 0.837 (95% CI: 0.771–0.903) vs. 0.650 (0.555–0.745)] and AFP-negative HCC [AUC: 0.856 (0.798–0.914)] and in discriminating HCC from LC (accuracy: 92.9% vs.64.71%). Higher DCP levels were associated with worse clinical behaviors and shorter disease-free survival. DCP not only is complementary to AFP in identifying AFP-negative HCC and in excluding AFP-positive non-HCC (liver cirrhosis), but also demonstrates improved performance in HCC surveillance, early diagnosis, treatment response and recurrence monitoring in the HBV-related population.     

Shewanella oneidensis MR-1-Induced Fe(III) Reduction Facilitates Roxarsone Transformation

Although microbial activity and associated iron (oxy)hydroxides are known in general to affect the environmental dynamics of 4-hydroxy-3-nitrobenzenearsonic acid (roxarsone), the mechanistic understanding of the underlying biophysico-chemical processes remains unclear due to limited experimental information. We studied how Shewanella oneidensis MR-1 –a widely distributed metal-reducing bacterium, in the presence of dissolved Fe(III), affects roxarsone transformations and biogeochemical cycling in a model aqueous system. The results showed that the MR-1 strain was able to anaerobically use roxarsone as a terminal electron acceptor and to convert it to a single product, 3-amino-4-hydroxybenzene arsonic acid (AHBAA). The presence of Fe(III) stimulated roxarsone transformation via MR-1-induced Fe(III) reduction, whereby the resulting Fe(II) acted as an efficient reductant for roxarsone transformation. In addition, the subsequent secondary Fe(III)/Fe(II) mineralization created conditions for adsorption of organoarsenic compounds to the yielded precipitates and thereby led to arsenic immobilization. The study provided direct evidence of Shewanella oneidensis MR-1-induced direct and Fe(II)-associated roxarsone transformation. Quantitative estimations revealed a candidate mechanism for the early-stage environmental dynamics of roxarsone in nature, which is essential for understanding the environmental dynamics of roxarsone and successful risk assessment.     

Heterologous expression of oxytetracycline biosynthetic gene cluster in Streptomyces venezuelae WVR2006 to improve production level and to alter fermentation process

Applied Microbiology and Biotechnology - Heterologous expression is an important strategy to activate biosynthetic gene clusters of secondary metabolites. Here, it is employed to activate and...