Stereoselective sulfate conjugation of isoproterenol in humans: Comparison of hepatic,intestinal, and platelet activity

The stereochemistry of sulfate conjugation of isoproterenol (ISO) was examined with human liver, intestine, and platelets as the phenolsulfotransferase (PST) enzyme source and PAP³⁵S as the cosubstrate. With the hepatic cytosol, two distinct sulfation reactions were identified, a high affinity reaction (K_m 5 to 50 μM) and a low affinity reaction (K_m 360 to 2,900 μM). The efficiency of sulfation (V_max/K_m) for both reactions was 5-fold higher for (+)- than for (?)-ISO. When the hepatic PSTs were resolved by ionexchange chromatography, it could be shown that the high affinity reaction was catalyzed by the monoamine (M) form and the low affinity reaction by the phenol (P) form of PST. Only the high affinity (M form) sulfation was detected in the jejunal cytosol with a V_max/K_m value 6.1-fold higher for (+)- than for (?)-ISO. Finally the platelet, as a potentially useful model tissue, also demonstrated only the high affinity M form reaction with a V_max/K_m value 5.7-fold higher for (+)- than for (?)-ISO. In summary, this study has shown that sulfation of ISO by PSTs in various human tissues is stereoselective and favors the inactive (+)-enantiomer over the active (?)-enantiomer by about 5-fold, a finding which should be considered in the therapeutic use of chiral drugs cleared by sulfate conjugation. © 1993 Wiley-Liss, Inc.     

瞬时受体电位香草醛亚家族1(TRPV1)的生物学功能

瞬时受体电位香草醛亚家族1 (TRPV1)又称辣椒素受体(VR1),是一类可被辣椒素、热(>43℃)、酸(pH<6.0)所激活的配体门控性非选择性阳离子通道,对Ca²⁺有高度通透性。早期研究发现TRPV1主要分布在神经系统并介导瘙痒及痛觉反应,近些年研究表明其在非神经细胞如肥大细胞、膀胱上皮细胞、单核细胞、皮肤角化上皮细胞、胰岛细胞等中也广泛分布,在代谢性疾病、消化、呼吸和心血管系统疾病、皮肤病及肿瘤等疾病的发生发展中均发挥了重要作用。本文介绍了TRPV1的分布、结构特征及其功能研究的最新进展,并重点综述了TRPV1介导的瘙痒和疼痛信号通路及以TRPV1为靶点的中草药研究进展,以期为以TRPV1为潜在治疗靶点相关疾病的中西医防治提供理论指导。     

酶类药物现状、问题及展望

随着生物制药的迅速发展,许多酶类药物应运而生,在治疗代谢疾病、心血管疾病、癌症等诸多疾病上发挥着越来越重要的作用。但是酶类药物也存在一些不足,如潜在的免疫原性、较短的体内半衰期,以及较差的组织靶向性,影响了酶类药物的疗效和应用。为克服这些缺点,人们已开发出多种技术,如通过糖基化、聚乙二醇修饰等分子工程技术提升酶蛋白药效,另一方面酶基因疗法也已成功用于多种酶缺陷疾病的治疗。基于酶类药物的迅速发展和广泛的应用前景,本文对酶类药物的现状进行较详细的阐述,并对酶类药物的优势、所存在的问题及未来发展趋势进行分析和评述。     

基于叶绿体基因组数据的芸香科属间系统发育初步分析（专题约稿）

该研究在人工控制水分条件下,设置3个干旱胁迫处理,选用3个主栽油菜品种‘陇油10号’、‘陇油2号’、‘青杂5号’幼苗进行盆栽试验,测定干旱胁迫条件下叶片相对含水量、叶绿素含量、光合气体交换参数及叶绿素荧光参数等指标,考察各指标在干旱胁迫过程中的变化特征,并通过主成分分析(PCA)和隶属函数法评价品种的抗旱性及其主要响应因子,以揭示西北地区油菜幼苗响应干旱胁迫的光合调控机制。结果表明：(1)各品种油菜幼苗的叶片相对含水量(RWC)均随干旱胁迫程度的递增而逐渐降低,最大水分亏缺(WSD)却逐渐上升。(2)各品种油菜幼苗叶片的叶绿素a含量、叶绿素总含量随着干旱胁迫程度的递增而先增加后递减,且同一种幼苗在不同处理间差异显著。(3)各品种油菜幼苗叶片的净光合速率(P_n)、水分利用效率(WUE)、单株生物量、气孔导度(G_s)、胞间CO₂浓度(C_i)均在受到干旱胁迫时迅速降低,且同一品种幼苗在不同处理间差异显著,而其叶片蒸腾速率(T_r)在干旱胁迫下无显著变化。(4)各品种油菜幼苗叶片光化学猝灭系数(qP)和非光化学猝灭系数(NPQ)随着干旱胁迫程度的递增先增加后递减,最大光化学效率(F_v/F_m)和电子传递速率(ETR)在受到干旱胁迫时迅速降低,且同一品种幼苗在不同处理间差异显著。(5)主成分分析结果表明,在油菜幼苗受到干旱胁迫时RWC、C_i、G_s、P_n、WUE、叶绿素总含量、叶绿素a含量和NPQ起主要调控作用;隶属函数法综合评价表明,3个品种油菜幼苗耐旱能力由高到低依次为‘陇油10号’＞‘陇油2号’＞‘青杂5号’。     

Design of a Robotized Magnetic Platform for Targeted Drug Delivery in the Cochlea

Inner ear disorders' treatment remains challenging due to anatomical barriers. Robotic assistance seems to be a promising approach to enhance inner ear treatments and, more particularly, lead to effective targeted drug delivery into the human cochlea. In this paper we present a combination of a micro-macro system that was designed and realized in order to efficiently control the navigation of magnetic nanoparticles in an open-loop scheme throughout the cochlea, considering that the magnetic particles cannot be located in real time.In order to respect the anatomical constraints, we established the characteristics that the new platform must present then proceeded to the design of the latter. The developed system is composed of a magnetic actuator that aims to guide nanoparticles into the cochlea. Mounted on a robotic manipulator, it ensures its positioning around the patient's head. The magnetic device integrates four parallelepiped-rectangle permanent magnets. Their arrangement in space, position and orientation, allows the creation of an area of convergence of magnetic forces where nanoparticles can be pushed/pulled to. To ensure the reachability of the desired orientations and positions, a 3 DOF robot based on a Remote Centre of Motion (RCM) mechanism was developed. It features three concurrent rotational joints that generate a spherical workspace around the head. The control of the latter is based on kinematic models.A prototype of this platform was realized to validate the actuation process. Both magnetic actuator and robotic manipulator were realized using an additive manufacturing approach. We also designed a virtual human head with a life-size cochlea inside. A laser was mounted on the end effector to track the positioning of the actuator. This permitted to experimentally prove the capacity of the robotic system to reach the desired positions and orientations in accordance with the medical needs.This promising robotic approach, makes it possible to overcome anatomical barriers and steer magnetic nanoparticles to a targeted location in the inner ear and, more precisely, inside the cochlea.     

Chemical Profile and Biological Activities of Fungal Strains Isolated from Piper nigrum Roots: Experimental and Computational Approaches

The current report describes the chemical investigation and biological activity of extracts produced by three fungal strains Fusarium oxysporum, Penicillium simplicissimum, and Fusarium proliferatum isolated from the roots of Piper nigrum L. growing in Vietnam. These fungi were namely determined by morphological and DNA analyses. GC/MS identification revealed that the EtOAc extracts of these fungi were associated with the presence of saturated and unsaturated fatty acids. These EtOAc extracts showed cytotoxicity towards cancer cell lines HepG2, inhibited various microbacterial organisms, especially fungus Aspergillus niger and yeast Candida albicans (the MIC values of 50–100 μg/mL). In α-glucosidase inhibitory assay, they induced the IC₅₀ values of 1.00-2.53 μg/mL were better than positive control acarbose (169.80 μg/mL). The EtOAc extract of F. oxysporum also showed strong anti-inflammatory activity against NO production and PGE-2 level. Four major compounds linoleic acid (37.346 %), oleic acid (27.520 %), palmitic acid (25.547 %), and stearic acid (7.030 %) from the EtOAc extract of F. oxysporum were selective in molecular docking study, by which linoleic and oleic acids showed higher binding affinity towards α-glucosidase than palmitic and stearic acids. In subsequent docking assay with inducible nitric oxide synthase (iNOS), palmitic acid, oleic acid and linoleic acid could be moderate inhibitors.     

In Silico Design of an Oseltamivir Derivative with Increased Affinity against Wild-Type and Mutant Variants of Neuraminidase and Hemagglutinin of Influenza A H1N1 Virus

Antiviral resistance has turned into a world concern nowadays. Influenza A H1N1 emerged as a problem at the world level due to the neuraminidase (NA) mutations. The NA mutants conferred resistance to oseltamivir and zanamivir. Several efforts were conducted to develop better anti-influenza A H1N1 drugs. Our research group combined in silico methods to create a compound derived from oseltamivir to be tested in vitro against influenza A H1N1. Here we show the results of a new compound derived from oseltamivir but with specific chemical modifications, with significant affinity either on NA (in silico and in vitro assays) or HA (in silico) from influenza A H1N1 strain. We include docking and molecular dynamics (MD) simulations of the oseltamivir derivative at the binding site onto NA and HA of influenza A H1N1. Additionally, the biological experimental results show that oseltamivir derivative decreases the lytic-plaque formation on viral susceptibility assays, and it does not show cytotoxicity. Finally, oseltamivir derivative assayed on viral NA showed a concentration-dependent inhibition behavior at nM, depicting a high affinity of the compound for the enzyme, corroborated with the MD simulations results, placing our designed oseltamivir derivative as a potential antiviral against influenza A H1N1.     

An optimized live bacterial delivery vehicle safely and efficaciously delivers bacterially transcribed therapeutic nucleic acids

There is an unmet need for delivery platforms that realize the full potential of next-generation nucleic acid therapeutics. The in vivo usefulness of current delivery systems is limited by numerous weaknesses, including poor targeting specificity, inefficient access to target cell cytoplasm, immune activation, off-target effects, small therapeutic windows, limited genetic encoding and cargo capacity, and manufacturing challenges. Here we characterize the safety and efficacy of a delivery platform comprising engineered live, tissue-targeting, non-pathogenic bacteria (Escherichia coli SVC1) for intracellular cargo delivery. SVC1 bacteria are engineered to specifically bind to epithelial cells via a surface-expressed targeting ligand, to allow escape of their cargo from the phagosome, and to have minimal immunogenicity. We describe SVC1's ability to deliver short hairpin RNA (shRNA), localized SVC1 administration to various tissues, and its minimal immunogenicity. To validate the therapeutic potential of SVC1, we used it to deliver influenza-targeting antiviral shRNAs to respiratory tissues in vivo. These data are the first to establish the safety and efficacy of this bacteria-based delivery platform for use in multiple tissue types and as an antiviral in the mammalian respiratory tract. We expect that this optimized delivery platform will enable a variety of advanced therapeutic approaches.     

Search for substrate-based inhibitors fitting the S2' space of malarial aspartic protease plasmepsin II.

Plasmepsin (Plm) has been identified as an important target for the development of new antimalarial drugs, since its inhibition leads to the starvation of Plasmodium falciparum. A series of substrate-based dipeptide-type Plm II inhibitors containing the hydroxymethylcarbonyl isostere as a transition-state mimic were synthesized. The general design principle was provision of a conformationally restrained hydroxyl group (corresponding to the set residue at the P2' position in native substrates) and a bulky unit to fit the S2' pocket.     

悬钩子属种质的评价

在进行了７省悬钩子资源调查的基础上,在南京建立了悬钩子属田间基因库。３年来对田间基因库内保存并开花结果的３０个种进行了开花结果性状的记栽和评价。内容包括果实特征,糖、酸、维生素类、氨基酸、矿质元素含量分析,染色体计数等。分析了种间和种内多样性物存在及在良种选育中利用的可能性。