何首乌不同器官和组织中蒽醌和茋类化合物的分布

目的探讨何首乌(Polygonum multiflorum Thunb.)不同营养器官和组织中蒽醌类和茋类化合物的分布,为合理利用何首乌提供科学依据.方法采用数码显微鉴定和TLC对何首乌的不同器官和组织部位进行了比较研究.结果从器官来看,何首乌藤茎、地下茎和块根中均含有蒽醌(大黄素和大黄素甲醚)和芪类(2,3,5,4'-四羟基二苯乙烯-2-O-β-D-葡萄糖苷)而叶和嫩茎则不舍;从组织部位来看,蒽醌类成分主要分布于韧皮部,而茋类成分主要分布于周皮和韧皮部,木质部最少.结论蒽醌类和茋类成分的产生与周皮的形成有一定的关系.蒽醌类化合物的含量可能与韧皮部的发达程度有关,茋类化合物主要产生和贮藏于薄壁细胞中.     

六盘山鸡爪大黄蒽醌类化合物积累特征的研究

采用多种组织化学方法研究了六盘山鸡爪大黄营养器官中蒽醌类化合物的积累特征.结果显示:蒽醌类化合物在根中分布于周皮的木栓层和栓内层、次生维管组织的维管射线和根中央的部分木薄壁细胞内,且维管射线是根中贮藏和积累蒽醌类化合物的主要组织;在根茎中分布于周皮的木栓层和栓内层、次生维管组织的形成层和维管射线,以及髓的异常维管束射线中,且维管射线是根茎中贮藏和积累蒽醌类化合物的主要组织;在茎中主要分布于表皮、近表皮皮层和维管束的维管束鞘及其薄壁细胞,大型和小型维管束之间和周围的部分薄壁细胞,以及髓射线中有不同程度的分布;在叶中主要积累在叶柄的表皮、叶柄和大叶脉的部分基本组织、维管束的部分薄壁细胞等部位.结果表明,六盘山鸡爪大黄的根和根茎是蒽醌类化合物贮藏和积累的主要器官,维管射线是其贮藏和积累的主要组织,而且各营养器官中蒽醌类化合物积累的数量与植物各相关器官组织的发育程度、细胞中含淀粉粒的多少存在着一定的相关性.     

六盘山鸡爪大黄葸醌类化合物积累特征的研究

采用多种组织化学方法研究了六盘山鸡爪大黄营养器官中蒽醌类化合物的积累特征。结果显示：蒽醌类化合物在根中分布于周皮的木栓层和栓内层、次生维管组织的维管射线和根中央的部分木薄壁细胞内,且维管射线是根中贮藏和积累蒽醌类化合物的主要组织;在根茎中分布于周皮的木栓层和栓内层、次生维管组织的形成层和维管射线,以及髓的异常维管束射线中,且维管射线是根茎中贮藏和积累蒽醌类化合物的主要组织;在茎中主要分布于表皮、近表皮皮层和维管束的维管束鞘及其薄壁细胞,大型和小型维管束之间和周围的部分薄壁细胞,以及髓射线中有不同程度的分布;在叶中主要积累在叶柄的表皮、叶柄和大叶脉的部分基本组织、维管束的部分薄壁细胞等部位。结果表明,六盘山鸡爪大黄的根和根茎是蒽醌类化合物贮藏和积累的主要器官,维管射线是其贮藏和积累的主要组织,而且各营养器官中蒽醌类化合物积累的数量与植物各相关器官组织的发育程度、细胞中含淀粉粒的多少存在着一定的相关性。     

微生物发酵炮制何首乌机理的初步研究

为探讨微生物发酵炮制何首乌的机制,采用HPLC考察何首乌微生物发酵前后二苯乙烯苷类和蒽醌类化学成分的变化。何首乌经米根霉发酵后,产生了新的蒽醌类成分大黄素-6-O-β-D-吡喃葡萄糖苷,而二苯乙烯苷类成分无变化。同时药理研究发现,大黄素-6-O-β-D-吡喃葡萄糖苷对家兔肠平滑肌的收缩作用弱于大黄素。由此推断,在何首乌发酵炮制过程中,米根霉可催化大黄素转化为大黄素-6-O-β-D-吡喃葡萄糖苷,从而降低何首乌的泻下作用。实验结果初步验证了微生物发酵炮制何首乌的科学性。     

六盘山鸡爪大黄根蒽醌类化合物组织化学定位的研究

采用组织化学方法研究了六盘山鸡爪大黄根蒽醌类化合物的组织化学定位特征及贮藏和积累的规律。结果表明：蒽醌类化合物在根内的贮藏是多位点的,在根周皮的木栓层和栓内层、次生维管组织的维管射线和根中央的部分木薄壁细胞内不同程度地贮藏和积累了一定数量的蒽醌类化合物,次生木质部的木射线和次生韧皮部的韧皮射线是主要贮藏和积累的部位,早期形成的维管射线中蒽醌类化合物的含量较晚期形成的射线含量高。     

中国蓼科植物化学成分研究进展

我国有蓼科植物13属约235种,37变种.通过对已报道的蓼科植物的化学成分综述分析,表明:大黄属、何首乌属、虎杖属与酸模属都含有蒽醌类化合物(如大黄素、大黄酸、大黄酚等);而养麦属与蓼属富含黄酮类化合物,极少有蒽醌类存在.蓼科植物化学成分主要为蒽醌类和黄酮类,鞣质在该科中普遍存在;生物碱很少、有些属还含有芪类.     

发酵法炮制何首乌的初步研究

为了筛选出可以专一性降解何首乌中蒽醌类成分而不破坏其有效成分二苯乙烯苷的菌种,降低何首乌的毒副作用,我们建立了一种炮制何首乌的新方法.采用HPLC法和UV分光光度计法,对不同菌株发酵的何首乌样品及其发酵前后的化学成分进行比较分析.结果显示:米根霉(Rhizojpus oryzae)、菌株YMS-010(Mucor.sp.)发酵样品的游离型总蒽醌、大黄素、大黄素甲醚的含量均有较大幅度的降低.菌株YMS-006(Aspergillus)、黑曲霉(Aapergillus nigers)、酿酒酵母(Saccharomyces cerevisiae)三株菌株发酵何首乌样品有未知成分产生,且含量较高.通过筛选发现米根霉、菌株YMS-006具有专一性降解蒽醌类成分而不破坏二苯乙烯苷的能力,获得了具有发酵炮制作用的菌株.     

斑马鱼模型评价何首乌中18种成分的肝脏毒性

首次用斑马鱼模型探索何首乌中18种成分的肝脏毒性作用,为何首乌的肝毒性物质基础研究提供依据。对肝脏荧光转基因斑马鱼给以高、中、低剂量的18种何首乌主要成分72 h,并分别于给药后24、48、72 h用荧光显微镜对其进行拍照。拍好的图片通过Image J软件进行肝脏面积和荧光强度分析。大黄素组、大黄酸组、芦荟大黄素组、大黄素-1-O-葡萄糖苷组、大黄素甲醚-8-O-葡萄糖苷组、芦荟大黄素-8-O-葡萄糖苷组及阳性对照组(对乙酰氨基酚)的肝脏面积和肝脏荧光强度与空白组相比显著降低;而大黄酚组、大黄素甲醚组、大黄素-8-O-葡萄糖苷组、大黄酸-8-O-葡萄糖苷组、大黄酚-1-O-葡萄糖苷组、大黄酚-8-O-葡萄糖苷组、芦荟大黄素-3-羟甲基葡萄糖苷组、白藜芦醇组、没食子酸组、儿茶素组、表儿茶素组的肝脏面积和肝脏荧光强度与空白组相比无显著差异;此外,二苯乙烯苷组的肝脏荧光强度与空白组相比显著增高。由此可见大黄素、大黄酸、芦荟大黄素、大黄素-1-O-葡萄糖苷、大黄素甲醚-8-O-葡萄糖苷、芦荟大黄素-8-O-葡萄糖苷对斑马鱼幼鱼肝脏具有一定毒性作用。何首乌的肝毒性作用可能还是由蒽醌类化合物介导,其物质基础与上述6种蒽醌成分有关,并以结合蒽醌为主。     

何首乌及其同属混伪品的鉴别研究

目的:探讨何首乌属3种药用植物何首乌、毛脉蓼及齿叶蓼根的性状、显微及化学成分的区别,为合理用药提供科学依据。方法:观察何首乌、毛脉蓼及齿叶蓼药材的性状和显微特征,并对3者的LC-ESI/MS图谱进行分析。结果何首乌、毛脉蓼、齿叶蓼根的形态特征、显微结构及化学成分上均存在明显差异:何首乌根断面黄棕色或红棕色,可见"云锦状花纹",韧皮部宽广,可见异常维管束和纤维束,二苯乙烯类成分含量较高。毛脉蓼断面土黄色或黄棕色,韧皮部宽,可见纤维束,主要含有大量的蒽醌类成分;而齿叶蓼断面为红色或紫红色,韧皮部狭窄,细胞多皱缩,未见异常维管束和纤维束,不含有蒽醌及二苯乙烯类成分,主要含有原花青素类成分。结论:何首乌与毛脉蓼在性状及成分类型上具有一定的相似性,只是含量的差异不同,而齿叶蓼则均具有较大的差异性,尤其是不含有何首乌属普遍具有的蒽醌类成分。     

毛脉酸模内生真菌蒽醌类次生代谢产物的筛选及含量分析

本文通过对毛脉酸模内生真菌的发酵培养得到其次生代谢产物,采用HPLC法对内生真菌中蒽醌类成分进行筛选。以大黄素、大黄酸、大黄酚、大黄素甲醚、芦荟大黄素五种蒽醌类成分为参照,筛选出3株真菌含大黄素、3株真菌含大黄酸、5株真菌含芦荟大黄素,其中含量最高为683μg/g、最低为8μg/g。将各菌株所含成分与各菌株分离部位的相应成分进行比较,相对宿主植物而言各菌株均有较高的含量。本实验分析方法准确、快捷,适用于毛脉酸模内生真菌的代谢产物研究。     

壳聚糖酶的克隆表达与壳寡糖的制备分析

目的:克隆壳聚糖酶基因于大肠杆菌中实现高表达,制备壳寡糖。方法:以枯草芽孢杆菌总DNA为模板扩增壳聚糖酶基因(CSN),克隆至载体pET23a(+)上,转化菌株BL21(DE3)。重组子经0.5 mmol/L IPTG诱导后,SDS-PAGE和质谱检测与鉴定重组酶。酶纯化后水解壳聚糖,薄层色谱分析其水解产物。结果:质谱证明壳聚糖酶(31.5kDa)成功表达,表达量占菌体总蛋白的45%左右。纯化后重组酶浓度为900 mg/L,纯度95%、回收率85%,酶活力为10 000 U/mg。壳聚糖降解产物为壳二糖至壳四糖。结论:原核表达载体pET23a(+)-CSN构建正确,壳聚糖酶表达量与活性高,适用于水解壳聚糖制备壳寡糖。     

国内外蝗害治理技术现状与展望

本文首先概述了国内外蝗虫发生与为害的态势,总结了现阶段我国蝗虫发生与为害的主要特点:即农田飞蝗暴发频繁而且严重,草原土蝗的发生时常造成严重的经济损失,而且侵入城市干扰市民生活,我国与周边国家之间蝗虫过境迁移频繁,使用化学农药污染环境和农产品;分析了国内外蝗虫防治对策与技术的发展现状,重点介绍了应急防治和可持续治理对策、...     

Synthesis and turnover of cerebrosides and phosphatidylserine of myelin and microsomal fractions of adult and developing rat brain.

The synthesis and turnover of cerebrosides and phospholipids was followed in microsomal and myelin fractions of developing and adult rat brains after an intracerebral injection of [U-14C]serine. The kinetics of incorporation of radioactivity into microsomal and myelin cerebrosides indicate the possibility of a precursor-product relationship between cerebrosides of these membranes. The specific radioactivity of myelin cerebrosides was corrected for the deposition of newly formed cerebrosides in myelin. Multiphasic curves were obtained for the decline in specific radioactivity of myelin and microsomal cerebrosides, suggesting different cerebroside pools in these membranes. The half-life of the fast turning-over pool of cerebrosides of myelin was 7 and 22 days for the developing and adult rat brain respectively. The half-life of the slowly turning-over pool of myelin cerebrosides was about 145 days for both groups of animals. The half-life of the rapidly turning-over microsomal cerebrosides was calculated to be 20 and 40 h for the developing and adult animals respectively. The half-life of the intermediate and slowly turning-over microsomal cerebrosides was 11 and 60 days respectively, for both groups of animals. The amount of incorporation of radioactivity into microsomal cerebrosides from L-serine was greatly decreased in the adult animals, and greater amounts of the precursor were directed towards the synthesis of phosphatidylserine. In the developing animals, considerable amounts of cerebrosides were synthesized from L-serine, besides phosphatidylserine. The time-course of incorporation indicated that a precursor-product relationship exists between microsomal and myelin phosphatidylserine. The half-life of microsomal phosphatidylserine was calculated to be about 8 h for the fast turning-over pool in both groups of animals.     

Identification and composition of the tonsillar and anal enterococcal and streptococcal flora of dogs and cats

Enterococcus faecalis was the most frequently isolated enterococcal species from anal swabs and tonsils of dogs and cats, although in the anal samples from dogs Ent. hirae was found almost as often as Ent. faecalis. Most Ent.faecium strains from dog tonsils differed from those associated with humans and other animals in that they fermented sorbitol. Typical Ent. avium as well as atypical Ent. avium -like strains were seen in dogs, while the related species Ent. raffinosus was associated with cat tonsils. Enterococcus cecorum also occurred mainly in cats. Certain atypical strains, presumptively identified as Ent. cecorum , shared characteristics with Ent. columbae.
The most frequent streptococcal species in tonsils of cats and dogs were Streptococcus suis and Strep. canis. Streptococcus canis and Strep. bovis predominated in anal swabs. The canine Strep. suis differed from the common porcine strains in fermenting mannitol.
Forty-seven of the 288 isolates examined could not be identified or related to known species. The characteristics of two groups of these bacteria, provisionally called 'Ton 31 group' and 'O7 group' are described.     

Molecular characterisation of species and genotypes of Cryptosporidium and Giardia and assessment of zoonotic transmission

The molecular characterisation of species and genotypes of Cryptosporidium and Giardia is essential for accurately identifying organisms and assessing zoonotic transmission. Results of recent molecular epidemiological studies strongly suggest that zoonotic transmission plays an important role in cryptosporidiosis epidemiology. In such cases the most prevalent zoonotic species is Cryptosporidium parvum. Genotyping and subtyping data suggest that zoonotic transmission is not as prevalent in the epidemiology of giardiasis. Molecular characterisation of Cryptosporidium and Giardia is a relatively recent application that is evolving as new genes are found that increase the accuracy of identification while discovering a greater diversity of species and yet unnamed taxa within these two important genera. As molecular data accumulate, our understanding of the role of zoonotic transmission in epidemiology and clinical manifestations is becoming clearer.     

白术同源四倍体的诱导和鉴定及其与二倍体过氧化物酶的比较

以白术（Atractylodes macrooephala Koidz.）二倍体组培苗为材料,对其四倍体诱导方法进行研究,共获得45个白术同源四倍体株系,为优良株系的选育提供了材料。此外,还分析比较了其中8个白术四倍体株系与二倍体的过氧化物酶同工酶（POD）的酶谱差异,发现四倍体各株系过氧化物酶同工酶谱比二倍体的均多了Rf0.310的谱带,且总过氧化物酶比活力也发生了很大改变,对探讨白术四倍体优良株系的生理生化机理具有一定的参考价值。     

Kinetics and thermodynamics of peroxidase- and laccase-catalyzed oxidation of N-substituted phenothiazines and phenoxazines

N -substituted phenothiazines (PTs) and phenoxazines (POs) catalyzed by fungal Coprinus cinereus peroxidase and Polyporus pinsitus laccase were investigated at pH 4–10. In the case of peroxidase, an apparent bimolecular rate constant (expressed as k _cat/K _m) varied from 1 ×10⁷M⁻¹s⁻¹to 2.6×10⁸M⁻¹s⁻¹ at pH 7.0. The constants for PO oxidation were higher in comparison to PT. pH dependence revealed two or three ionizable groups with pK _a values of 4.9–5.7 and 7.7–9.7 that significantly affected the activity of peroxidase. Single-turnover experiments showed that the limiting step of PT oxidation was reduction of compound II and second-order rate constants were obtained which were consistent with the constants at steady-state conditions. Laccase-catalyzed PT and PO oxidation rates were lower; apparent bimolecular rate constants varied from 1.8×10⁵M⁻¹s⁻¹ to 2.0×10⁷M⁻¹s⁻¹ at pH 5.3. PO constants were higher in comparison to PT, as was the case with peroxidase. The dependence of the apparent bimolecular constants of compound II or copper type 1 reduction, in the case of peroxidase or laccase, respectively, was analyzed in the framework of the Marcus outer-sphere electron-transfer theory. Peroxidase-catalyzed reactions with PT, as well as PO, fitted the same hyperbolic dependence with a maximal oxidation rate of 1.6×10⁸M⁻¹s⁻¹ and a reorganization energy of 0.30 eV. The respective parameters for laccase were 5.0×10⁷M⁻¹s⁻¹ and 0.29 eV. Received: 20 September 1999 / Accepted: 24 February 2000