清香桂碱A的结构

清香桂碱A (sarcorucininc A)是黄杨科清香桂属植物(Sarcococca ruscifoliaStapf.)中含量最高的一个新甾体生物碱(约达地上部分干重的0.1％),量较微的清香桂碱D (sarcorucinine D) 结构已报道。由于碱A性质奇异,虽经多种簿层方法检测为单一斑点,但~(13)C NMR谱的碳数目使我们十分困惑,怀疑它是否为不饱和同系物混晶。而氢化、溴化、碱解均表现出特异的化学行为,因此只好用X—晶体衍射分析方法测定其结构。现将其一般性质及X—晶体衍射分析结果报道,测定细节将和清香桂碱B另文报告。     

大叶清香桂中甾体生物碱的分离与鉴定

从大叶清香桂分离鉴定了３个新甾体生物碱大叶清香桂碱Ａ,Ｂ,Ｃ（Ⅰ,Ⅱ,Ⅲ）和３个已知化合物矮陀陀碱Ｆ（Ⅳ）、矮陀陀胺碱Ａ（Ⅴ）和富贵草碱（Ⅵ）。通过光谱分析和化学转化,确定３个新化合物的化学结构为：２０ａ－二甲胺基－４β－乙酰氧－３β－千里酰胺基－５ａ－孕甾烷（Ⅱ）,２０ａ－二甲胺基－４β－羟基－３－千里酰胺基－△＾２（３）－孕甾烯（Ⅱ)化合物Ⅱ的4-乙酰貂（Ⅲ）。     

MS/MS技术在确定清香桂碱A和A_1混晶结构中的应用

清香桂(Sarcococca ruscifolia)植物中得到一个清香桂碱A和A_1的共晶,我们通过化学及光谱方法确定了清香桂碱A_1及B的化学结构,并用MS/MS技术证实了这个混晶的结构。这几个生物碱的结构为,碱A(1)为Δ~(14,16)-3α-二甲胺孕甾二烯;碱A_1(2)为Δ~(16)-3α-甲基甲酰胺孕甾烯;碱B(5)为Δ~(16)-3α-二甲胺孕甾烯-20-酮。     

金丝矮陀陀植物中的二个新甾体生物碱甙

从金丝矮陀陀植物中得到了二个新甾体生物碱甙——矮陀陀甙A、B。经光谱分析,结构测定,分别为20α-二甲胺-3-O-β-D葡萄糖基-5α-孕甾烷醇和20α-二甲胺-3-O-β-D葡萄糖基-5(6)-孕甾烯醇。     

ABA和NaCl对碱蓬多胺和脯氨酸代谢的影响

比较了 5 0 μmol/L的ABA和 4 0 0mmol/L的NaCl对碱蓬植株内脯氨酸 (Pro)和多胺 (PAs)含量和代谢关键酶活性的影响。结果表明 :ABA处理能诱导碱蓬植株吡咯啉 5 羧酸合成酶 (P5CS)、鸟氨酸脱羧酶(ODC)、多胺氧化酶 (PAO)和脯氨酸脱氢酶 (ProDH)活性上升 ,Pro和游离多胺含量增加。ABA NaCl处理促进碱蓬植株体内Pro和PA的积累。与NaCl处理相比 ,ABA NaCl处理后碱蓬植株P5CS活性显著上升 ,ProDH活性变化不明显 ,ODC活性极显著上升 ,PAO和转谷酰胺酶 (TGase)活性上升 ,从而使Pro和游离多胺含量均显著上升 ,游离态多胺 (Spd PAx) /Put提高 ,结合态多胺总量上升。ABA NaCl处理对碱蓬植株体内Pro和PAs合成的促进与其对生长速率的促进效应相一致     

河北大海陀自然保护区植物区系及其与相邻保护区的关系

于2012～2013年对河北大海陀自然保护区进行了3次全面踏查,并根据植物群落类型及其分布设置样地进行植物区系组成的详细调查,在此基础上分析了大海陀保护区维管束植物的区系组成与分布类型,并将其与周边相邻4个保护区的植物区系组成进行了比较,以明确大海陀自然保护区植物区系及其特点,为该地区的植物多样性保护提供依据。结果表明:(1)大海陀自然保护区共有野生维管束植物900种,隶属于108科,429属。其中蕨类植物14科19属28种,裸子植物2科3属3种,被子植物92科407属869种。(2)保护区内区域单种属数达到249个,占总属数的58.0%,反映了该区植物区系组成的复杂性。保护区内维管束植物属可划分为15个分布区类型,且温带性质的属是构成该区植物区系的主要组成部分,保护区内种子植物温带分布类型(8～14型)共281属,占总属数的78.3%。(3)对大海陀自然保护区与周边相邻的4个保护区植物区系组成比例进行比较发现,大海陀自然保护区与纬度相似的河北小五台山自然保护区、河北雾灵山自然保护区植物区系组成比例最为相似,同时也说明大海陀自然保护区内植物区系组成比例与所处地理区域应有的植物区系组成比例一致。     

安徽省大别山陀尖山区植物区系的研究

陀尖山区有维管束植物119种,隶属于552属,151科,是大别山植物区系最丰富,最具有代表性的地区之一。作者认为大别山南北坡植物不存在明显差异,大别山植物区系作为一个整体属于华东植物区系。陀尖山区植物区系与庐山、神农架和黄山的植物区系关系最为密切,相似程度三者不相上下;陀尖山区乃至整个大别山区构成了华东区与华中区联系的纽带。     

黄草乌碱乙和碱丁的结构

我们从云南民间草药黄草乌(Aconitum vilmorrianum Kom.)根中分离到六个二萜生物碱,其中三个为乌头碱型酯碱:滇乌碱(Yunaconitine)(Ⅰ)、黄草乌碱甲(Vilmorrianine A)(Ⅱ)和碱丙(Vilmorrianine C)(Ⅲ)已交发表。本文报告同一层析柱上分到的另两个乌头碱型胺醇,一个为朱元龙等曾分到的黄草乌碱乙(Vilmorrianine B),另一个为新胺醇,命名为黄草乌碱丁(Vilmorrianine D)。     

A Unique Protease Cleavage Site Predicted in the Spike Protein of the Novel Pneumonia Coronavirus (2019-nCoV) Potentially Related to Viral Transmissibility

正Dear Editor,In December 2019, a novel human coronavirus caused an epidemic of severe pneumonia(Coronavirus Disease 2019,COVID-19) in Wuhan, Hubei, China(Wu et al. 2020; Zhu et al. 2020). So far, this virus has spread to all areas of China and even to other countries. The epidemic has caused 67,102 confirmed infections with 1526 fatal cases     

Curcuminoids as inhibitors of thioredoxin reductase: A receptor based pharmacophore study with distance mapping of the active site

Curcumin is the yellow pigment of turmeric that interacts irreversibly forming an adduct with thioredoxin reductase (TrxR), an enzyme responsible for redox control of cell and defence against oxidative stress. Docking at both the active sites of TrxR was performed to compare the potency of three naturally occurring curcuminoids, namely curcumin, demethoxy curcumin and bis-demethoxy curcumin. Results show that active sites of TrxR occur at the junction of E and F chains. Volume and area of both cavities is predicted. It has been concluded by distance mapping of the most active conformations that Se atom of catalytic residue SeCYS498, is at a distance of 3.56 from C13 of demethoxy curcumin at the E chain active site, whereas C13 carbon atom forms adduct with Se atom of SeCys 498. We report that at least one methoxy group in curcuminoids is necessary for interation with catalytic residues of thioredoxin. Pharmacophore of both active sites of the TrxR receptor for curcumin and demethoxy curcumin molecules has been drawn and proposed for design and synthesis of most probable potent antiproliferative synthetic drugs.     

The structure, reproduction and taxonomy of Vidalia and Osmundaria (Rhodophyta, Rhodomelaceae)

Comprises species occurring mostly in subtidal habitats in tropical, subtropical and warm-temperate areas of the world. An analysis of the type species, V. spiralis (Sonder) Lamouroux ex J. Agardh, a species from Australia, establishes basic characters for distinguishing species in the genus. These characters are (1) branching patterns of thalli, (2) flat blades that may be spiralled on their axis, (3) width of the blade, (4) primary or secondary derivation of sterile and fertile branchlets and (5) position of sterile and fertile branchlets on the thalli. Application of the latter two characters provides an important basic method for separation of species into three major groups. Osmundaria , a genus known only in southern Australia, was studied in relation to Vidalia , and its separation from the Vidalia assemblage is not accepted. Species of Vidalia therefore are transferred to the older genus name, Osmundaria. Two new species, Osmundaria papenfussii and Osmundaria oliveae are described from Natal. Confusion in the usage of the epithet, Vidalia fimbriala Brown ex Turner has been clarified, and Vidalia gregaria Falkenberg, described as an epiphyte on Osmundaria pro/ifera Lamouroux, is revealed to be young branches of the host, Osmundaria prolifera.     

New or rare chromosome counts in Artemisia L. (Asteraceae, Anthemideae) and related genera from Kazakhstan

Fifteen chromosome counts of six Artemisia taxa and one species of each of the genera Brachanthemum, Hippolytia, Kaschgaria, Lepidolopsis and Turaniphytum are reported from Kazakhstan. Three of them are new reports, two are not consistent with previous counts and the remainder are confirmations of very scarce (one to four) earlier records. All the populations studied have the same basic chromosome number, x = 9, with ploidy levels ranging from 2x to 6x. Some correlations between ploidy level, morphological characters and distribution are noted.     

肝癌中HBV和HCV基因和抗原的分布及意义

采用原位分子杂交方法检测HCV RNA及HBV X基因;采用免疫组织化学方法研究HCV核心抗原,非结构区C33c抗原及HBxAg在肝细胞肝癌中的定位及分布.结果表明(1)HCV RNA、HBV X基因在肝细胞肝癌组织检出率分别为40%(55/136)和82%(112/136).HCV RNA定位于癌细胞的胞浆内,阳性细胞呈散在、灶状及弥漫分布三种形式;HBV X基因在肝癌细胞中的分布呈胞浆型、核型及核浆型,阳性细胞也呈上述三种分布形式;(2)HCV C33c抗原、核心抗原在肝细胞肝癌中的阳性率为81%(133/164)及86%(141/164).C33c抗原定位于癌细胞及肝细胞的胞浆内;核心抗原既定位于癌细胞核中,又可定位于胞浆中.C33c抗原阳性细胞以灶状分布为主;而核心抗原阳性细