Computational gibberellin‐binding channel discovery unraveling the unexpected perception mechanism of hormone signal by gibberellin receptor

Gibberellins (GAs) are phytohormones essential for many developmental processes in plants. In this work, fundamental mechanism of hormone perception by receptor GID1 has been studied by performing computational simulations, revealing a new GA‐binding channel of GID1 and a novel hormone perception mechanism involving only one conformational state of GID1. The novel hormone perception mechanism demonstrated here is remarkably different from the previously proposed/speculated mechanism [Murase et al., Nature 2008 , 456, 459] involving two conformational states (“OPEN” and “CLOSED”) of GID1. According to the new perception mechanism, GA acts as a “conformational stabilizer,” rather than the previously speculated “allosteric inducer,” to induce the recognition of protein DELLA by GID1. The novel mechanistic insights obtained in this study provide a new starting point for further studies on the detailed molecular mechanisms of GID1 interacting with DELLA and various hormones and for mechanism‐based rational design of novel, potent growth regulators that target crops and ornamental plants. © 2013 Wiley Periodicals, Inc.     

Eight new polyketide metabolites from the fungus Pestalotiopsis vaccinii endogenous with the mangrove plant Kandelia candel (L.) Druce

Seven new prenylated phenols, vaccinols A–G (1–7), and one new naphthalene derivative, vaccinal A (8), together with five known phenol derivatives (9–13) were isolated from Pestalotiopsis vaccinii (cgmcc3.9199) endogenous with the mangrove plant Kandelia candel (L.) Druce (Rhizophoraceae). The new structures were established on the basis of spectroscopic analysis, optical rotation, CD spectra, quantum ECD calculations. Furthermore, the absolute configuration of compound 1 was unambiguously elucidated by single-crystal X-ray diffraction analysis using the Flack parameter. Most new compounds were tested for their antiviral (EV71), cytotoxic, antituberculosis, and anti-inflammatory effects. Among them, compound 8 exhibited in vitro anti-enterovirus 71 (EV71) with IC₅₀ value of 19.2 μM. In addition, 8 showed potent COX-2 inhibitory activity with IC₅₀ value of 1.8 μM.     

基于曲波变换的视网膜血管图像增强算法

视网膜血管图像存在像素对比度低等特点,干扰正常的视网膜图像分割.针对视网膜血管的图像特性,提出了一种改进的基于曲波变换的视网膜血管图像增强算法.首先选取视网膜图像的绿色通道分量进行预处理,然后通过对变换系数的自适应增强完成图像的增强处理,并结合改进的形态学变换,实现图像细节的增强和背景噪声的抑制,使得图像对比度得到增强,细节信息更加明显.通过与其他增强算法的比较表明,该算法在增强对比度、降低噪声干扰等方面优于其他算法.     

植物生长物质对牛膝生长及主要药用成分积累的影响

采用不同植物生长物质组合对牛膝幼苗进行喷施处理和植物化学分析相结合的方法,研究植物生长物质对牛膝生长及其主要药用成分合成的影响.结果表明:1.0mg·L-1 IBA+1.0mg·L-1 MJ(T4)协同处理最有利于牛膝地下部分生物量的增加;1.0mg·L-1 IBA+1.0mg·L-1 6-BA(T3)协同处理最有利于牛膝根中齐墩果酸的积累;1.0mg·L-1 IBA+2.0mg·L-1 NAA(T2)和1.0mg·L-1 IBA+1.0mg·L-1 6-BA(T3)处理最有利于牛膝根中蜕皮甾酮的积累.综合考虑各项指标,1.0mg·L-1 IBA+1.0mg·L-1 6-BA(T3)处理无论是对牛膝的生长还是主要药用成分三萜皂苷和蜕皮甾酮的积累均比对照有显著性提高,最有利于牛膝药材产量和品质的提高.     

浙江嵊泗小洋山岛植物分布特点和环境因子分析

浙江嵊泗小洋山岛发育至今,生物、非生物环境因子起着重要作用.其中,成岛年龄、高程、土壤种类、土壤养分、土壤含盐量、土壤p H值等影响着植物群落的形成、定居与演替.在多年野外调查基础上,以时空跨度,运用PC-ORD生态学多变量分析软件中的典范对应分析(CCA)二维排序方法,阐述了小洋山岛植物群落结构和植物多样性,并对该岛植物群落的演替现状和植被恢复进行了二维排序分析.结果表明:(1)小洋山岛植物群落结构复杂多样有维管植物300种;(2)人们对小洋山岛进行各种建设的同时且先锋植物群正在发生,并为研究分析该岛植被恢复及其整个生态系统提供了基础资料.     

Brief survey on phytochemicals to prevent COVID-19

BackgroundThe recent pandemic by COVID-19 is a global threat to human health. The disease is caused by SARS-CoV-2 and the infection rate is increased more quickly than MERS and SARS as their rapid adaptation to varied climatic conditions through rapid mutations. It becomes more severe due to the lack of proper therapeutic drugs, insufficient diagnostic tool, scarcity of appropriate drug, life supporting medical facility and mostly lack of awareness. Therefore, preventive measure is one of the important strategies to control. In this context, herbal medicinal plants received a noticeable attention to treat COVID-19 in Indian subcontinent. Here, 44 Indian traditional plants have been discussed with their novel phytochemicals that prevent the novel corona virus. The basic of SARS-CoV-2, their common way of transmission including their effect on immune and nervous system have been discussed. We have analysed their mechanism of action against COVID-19 following in-silico analysis. Their probable mechanism and therapeutic approaches behind the activity of phytochemicals to stimulate immune response as well as inhibition of viral multiplication discussed rationally. Thus, mixtures of active secondary metabolites/phytochemicals are the only choice to prevent the disease in countries where vaccination will take long time due to overcrowded population density.     

分散固相萃取-超高效液相色谱-串联质谱法测定水产品中5种硝基咪唑类和6种苯二氮卓类药物北大核心CSCD

建立了分散固相萃取-超高效液相色谱-串联质谱法同时测定水产品中5种硝基咪唑类和6种苯二氮卓类药物残留的方法。样品用1%(v/v)氨水乙腈提取,提取液经十八烷基键合硅胶(C18)和N-丙基乙二胺(PSA)吸附剂净化,在45℃下用氮气吹至近干,用1 mL甲醇-水(1∶9,v/v)溶液复溶,过0.22μm尼龙-66滤膜后用超高效液相色谱-串联质谱测定。目标化合物采用Kinetex F5色谱柱(100 mm×3.0 mm,2.6μm)分离,以0.1%(v/v)甲酸水溶液和甲醇作为流动相进行梯度洗脱,在电喷雾离子源(ESI)、正离子扫描和多反应监测(MRM)模式下进行测定,基质匹配外标法定量。结果表明,5种硝基咪唑类和6种苯二氮卓类药物在8.5 min内完成色谱分离分析,目标物在0.5~20μg/L范围内线性关系良好,相关系数均大于0.995,检出限和定量限分别为0.2~0.5μg/kg和0.5~1.0μg/kg。以草鱼、对虾和大黄鱼为样品基质,在3个不同的添加水平下,5种硝基咪唑类和6种苯二氮卓类药物的平均回收率为73.2%~110.6%,相对标准偏差(RSD)小于15%。本研究建立的方法具有简单、快速、灵敏度高和成本低等优势,可用于水产品中5种硝基咪唑类和6种苯二氮卓类药物的快速检测。该方法的建立为我国水产品质量安全相关监管部门同时监控水产品中硝基咪唑类和苯二氮卓类药物残留提供了技术支持。     

Biogenic Synthesis of Gold Nanoparticles on a Green Support as a Reusable Catalyst for the Hydrogenation of Nitroarene and Quinoline

Direct attachment of gold nanoparticles to a green support without the use of an external reducing agent and using it for removing toxic pollutants from wastewater, i. e., reduction of nitroarene to amine, are described. A novel approach involving the reduction of gold by the jute plant (Corchorus genus) stem-based (JPS) support itself to form nanoparticles (AuNPs) to be used as a catalytic system (‘dip-catalyst’) and its catalytic activity for the hydrogenation of series of nitroarenes in aqueous media are presented. AuNPs/JPS catalyst was characterized using SEM, UV-Vis, FTIR, TEM, XPS, and ICP-OES. Confined area elemental mapping exhibits uniform and homogeneous distribution of AuNPs on the support surface. TEM shows multi-faceted AuNPs in the range of 20–30 nm. The reactivity of AuNPs/JPS for the transfer hydrogenation of nitroarene as well as hydrogenation of quinoline under molecular H₂ pressure was evaluated. Sodium borohydride, when used as the hydrogen source, demonstrates a high catalytic efficiency in the transfer hydrogenation reduction of 4-nitrophenol (4-NP). Quinoline is quantitatively and chemoselectively hydrogenated to 1,2,3,4-tetrahydroquinoline (py-THQ) using molecular hydrogen. Reusability studies show that AuNPs are stable on the support surface and their selectivity is not affected.     

Zinc Oxide Nanoparticles and Zinc Sulfate Impact Physiological Parameters and Boosts Lipid Peroxidation in Soil Grown Coriander Plants (Coriandrum sativum)

The objective of this study was to determine the oxidative stress and the physiological and antioxidant responses of coriander plants (Coriandrum sativum) grown for 58 days in soil with zinc oxide nanoparticles (ZnO NPs) and zinc sulfate (ZnSO₄) at concentrations of 0, 100, 200, 300, and 400 mg of Zn/kg of soil. The results revealed that all Zn compounds increased the total chlorophyll content (CHLt) by at least 45%, compared to the control group; however, with 400 mg/kg of ZnSO₄, chlorophyll accumulation decreased by 34.6%. Zn determination by induction-plasma-coupled atomic emission spectrometry (ICP–AES) showed that Zn absorption in roots and shoots occurred in plants exposed to ZnSO₄ at all concentrations, which resulted in high levels of hydrogen peroxide (H₂O₂) and malondialdehyde (MDA). Only at 400 mg/kg of ZnSO₄, a 78.6% decrease in the MDA levels was observed. According to the results, the ZnSO₄ treatments were more effective than the ZnO NPs to increase the antioxidant activity of catalase (CAT), ascorbate peroxidase (APX), and peroxidases (POD). The results corroborate that phytotoxicity was higher in plants subjected to ZnSO₄ compared to treatments with ZnO NPs, which suggests that the toxicity was due to Zn accumulation in the tissues by absorbing dissolved Zn⁺⁺ ions.     

Synthesis and Investigation of Tetrahydro-β-carboline Derivatives as Inhibitors of Plant Pathogenic Fungi

A series of tetrahydro-ß-carbolines substituted with an alkyl or acyl side chain was synthesized and screened for its antifungal activity against plant pathogenic fungi (Bipolaris oryzae, Curvularia lunata, Fusarium semitectum, and Fusarium fujikuroi). The structure activity relationship revealed that the substituent at the piperidine nitrogen plays an important role for increasing antifungal activities. In this series, 2-octyl-2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indole (3g) displayed potent antifungal activities with a minimum inhibitory concentration of 0.1 μg/mL, including good inhibitory activity to the radial growth of fungus at a concentration of 100 μg/mL compared to amphotericin B.