不同演替阶段热带森林地表凋落物和土壤节肢动物群落特征

为了解不同演替阶段热带森林土壤节肢动物群落结构特征及其与地表凋落物的关系, 2001年9月采用样线调查法对西双版纳23年次生林、35年次生林、季节雨林地表凋落物及其中的土壤节肢动物进行了调查。所获数据表明, 地表凋落物数量(现存量干重)和质量(N和C/N)总体上表现为35年次生林最好, 23年次生林次之; 蜱螨目和弹尾目为3林地地表凋落物土壤节肢动物群落优势类群, 膜翅目蚂蚁、马陆目、鞘翅目、双翅目和半翅目为常见类群。土壤节肢动物个体密度和个体相对密度均表现为35年次生林>季节雨林>23年次生林。群落的丰富度指数以季节雨林最高, 多样性和均匀度指数显示为23年次生林最高, 35年次生林的优势度指数最高, 3林地土壤节肢动物群落类群组成相似性达到较好水平。相关分析表明, 3种不同演替阶段热带森林土壤节肢动物个体密度与林地地表凋落物现存量呈正相关, 而现存凋落物N元素储量与土壤节肢动物的相关性仅表现在23年次生林和季节雨林。研究认为, 热带森林土壤节肢动物群落的发展与森林植被演替密切相关, 其群落个体数量和多样性受森林地表凋落物数量、质量的调控, 但其他环境因素如捕食效应、人为干扰等影响亦不可忽视。     

A chemiluminescence method to detect hydroquinone with water‐soluble sulphonato‐(salen)manganese(III) complex as catalyst

A water‐soluble sulphonato‐(salen)manganese(III) complex with excellent catalytic properties was synthesized and demonstrated to greatly enhance the chemiluminescence signal of the hydrogen peroxide ? luminol reaction. Coupled with flow‐injection technique, a simple and sensitive chemiluminescence method was first developed to detect hydroquinone based on the chemiluminescence system of the hydrogen peroxide–luminol–sulphonato‐(salen)manganese(III) complex. Under optimal conditions, the assay exhibited a wide linear range from 0.1 to 10 ng mL^–1 with a detection limit of 0.05 ng mL^–1 for hydroquinone. The method was applied successfully to detect hydroquinone in tap‐water and mineral‐water, with a sampling frequency of 120 times per hour. The relative standard deviation for determination of hydroquinone was less than 5.6%, and the recoveries ranged from 96.8 to 103.0%. The ultraviolet spectra, chemiluminescence spectra, and the reaction kinetics for the peroxide–luminol–sulphonato‐(salen)manganese(III) complex system were employed to study the possible chemiluminescence mechanism. The proposed chemiluminescence analysis technique is rapid and sensitive, with low cost, and could be easily extended and applied to other compounds. Copyright © 2015 John Wiley & Sons, Ltd.     

金花茶的分类和地理分布

为了全面了解金花茶的种质资源和进一步开展有关研究,向有关部门开发利用与保护金花茶提供依据,本文试图论述金花茶的分类和地理分布,讨论了正式发表的金花茶13种、1交种,作了分种检索表,并对金花茶的分布范围,分布中心及分布集中、重叠的原因等,提出我们的浅见,以供参考和讨论。     

凋亡抑制基因Survivin与肿瘤的关系

Survivin是一种新的凋亡抑制蛋白,其具有抗凋亡的特征性结构。Survivin在肿瘤的发生发展中起重要作用,与肿瘤预后密切相关,有望成为一种广谱的肿瘤诊断标记物,并可能是抗肿瘤治疗的重要标靶。     

A nuclear function of Hu proteins as neuron-specific alternative RNA processing regulators

Recent advances in genome-wide analysis of alternative splicing indicate that extensive alternative RNA processing is associated with many proteins that play important roles in the nervous system. Although differential splicing and polyadenylation make significant contributions to the complexity of the nervous system, our understanding of the regulatory mechanisms underlying the neuron-specific pathways is very limited. Mammalian neuron-specific embryonic lethal abnormal visual-like Hu proteins (HuB, HuC, and HuD) are a family of RNA-binding proteins implicated in neuronal differentiation and maintenance. It has been established that Hu proteins increase expression of proteins associated with neuronal function by up-regulating mRNA stability and/or translation in the cytoplasm. We report here a novel function of these proteins as RNA processing regulators in the nucleus. We further elucidate the underlying mechanism of this regulation. We show that in neuron-like cells, Hu proteins block the activity of TIA-1/TIAR, two previously identified, ubiquitously expressed proteins that promote the nonneuronal pathway of calcitonin/calcitonin gene-related peptide (CGRP) pre-mRNA processing. These studies define not only the first neuron-specific regulator of the calcitonin/CGRP system but also the first nuclear function of Hu proteins.     

Synthesis of beta-(1-->6)-branched beta-(1-->3) glucohexaose and its analogues containing an alpha-(1-->3) linked bond with antitumor activity

A beta-(1-->6)-branched beta-(1-->3)-glucohexaose, present in many biologically active polysaccharides from traditionally herbal medicines such as Ganoderma lucidum, Schizophyllum commune and Lentinus edodes, was synthesized as its lauryl glycoside 32, and its analogues 18, 20 and 33 containing an alpha-(1-->3) linked bond were synthesized. It is interesting to find that coupling of a 3,6-branched acylated trisaccharide trichloroacetimidate donor 9 with 3,6-branched acceptors 13 and 16 with 3'-OH gave the alpha-(1--> 3)-linked hexasaccharides 17 and 19, respectively, in spite of the presence of C-2 ester capable of neighboring group participation. However, coupling of 9 with 4-methoxyphenyl 4,6-O-benzylidene-beta-D-glucopyranoside (27) selectively gave beta-(1-->3)-linked tetrasaccharide 28. Simple chemical transformation of the tetrasaccharide 28 gave acylated tetrasaccharide trichloroacetimidate 29. Coupling of 29 with lauryl (1-->6)-linked disaccharide 26 with 3-OH gave beta-(1-->3)-linked hexasaccharide 30 as the major product. Bioassay showed that in combination with the chemotherapeutic agent cyclophospamide (CPA), the hexaose 18 at a dose of 0.5-1mg/kg substantially increased the inhibition of S(180) for CPA, but decreased the toxicity caused by CPA. Some of these oligosaccharides also inhibited U(14) noumenal tumor in mice effectively.     

PPARgamma ligands suppress proliferation of human urothelial basal cells in vitro

Expression of peroxisome proliferator-activated receptor (PPAR) gamma in the human urinary tract through embryonic development suggests its possible roles in the development, proliferation, and differentiation of uroepithelium. Little is known, however, about physiological roles of PPARgamma in the urinary tract. We investigated effects of PPARgamma ligands on the proliferation of normal human urothelial cells and stromal cells cultivated from surgical specimens. Active proliferation in vitro as well as high molecular weight cytokeratin expression indicated that cultured urothelial cells possess basal cell phenotype. PPARgamma protein, expressed predominantly in the epithelial layer of the normal human urinary tract in vivo, was abundantly expressed in urothelial cells but barely detectable in stromal cells in vitro. Natural ligand for PPARgamma, 15-deoxy-Delta(12,14) prostaglandin J(2) (15d-PGJ(2)), as well as synthetic ones, troglitazone and pioglitazone, suppressed proliferation of the urothelial cells dose-dependently. These effects were PPARgamma specific because clofibrate or PGF(2alpha) did not affect proliferation of urothelial cells. Neither 9-cis retinoic acid or all-trans retinoic acid (ATRA) at 1 microM showed any synergism on the antiproliferative effects of PPARgamma ligands. Urothelial cells treated with PPARgamma ligands showed drastic morphologic changes and cell cycle arrest at G0/G1 phase accompanied with increased mRNA level of a cyclin-dependent kinase inhibitor p21(WAF1/CIP1). Since 15d-PGJ(2) is present in vivo during the resolution phase of inflammation, these results indicated that PPARgamma might be involved in the terminal phase of urothelial re-epithelialization processes.