4种秦艽属植物不同器官中4种环烯醚萜苷成分含量的比较分析

利用HPLC法测定了秦艽(Gentiana macrophylla Pall.)、粗茎秦艽(G.crassicaulis Duthie ex Burk.)、麻花秦艽(G.straminea Maxim.)和小秦艽(G.dahurica Fisch.)根、茎、叶和花中4种环烯醚萜苷成分(包括马钱苷酸、獐牙菜苦苷、龙胆苦苷和獐牙菜苷)的含量,并对来源于不同产地秦艽和小秦艽不同器官4种环烯醚萜苷成分的含量进行了比较。结果显示:4种秦艽属植物不同器官4种环烯醚萜苷成分含量差异明显,来源于3个产地(陕西太白、甘肃西河乡和马狭)的秦艽和2个产地(青海互助和陕西麟游)的小秦艽不同器官中4种环烯醚萜苷含量也均具有明显差异。4种秦艽属植物根、茎、叶和花中龙胆苦苷和马钱苷酸总量分别为质量分数5.996%～10.869%、0.310%～4.065%、0.235%～4.138%和0.545%～5.591%;根中獐牙菜苦苷和獐牙菜苷的质量分数分别为0.516%～0.953%和0.042%～0.210%,茎中分别为0.173%～0.383%和0.031%～1.700%,叶中分别为0.068%～0.684%和0.020%～3.208%,花中分别为0.460%～0.832%和0.138%～3.827%。粗茎秦艽各器官龙胆苦苷和马钱苷酸总量均最高,小秦艽各器官龙胆苦苷和马钱苷酸总量均最低,总体上,秦艽和粗茎秦艽中龙胆苦苷和马钱苷酸总量高于小秦艽和麻花秦艽;小秦艽茎、叶和花中獐牙菜苷含量均最高,而秦艽茎和叶及粗茎秦艽花中獐牙菜苷含量均最低。4种秦艽属植物根部龙胆苦苷和马钱苷酸含量均明显高于茎、叶和花,獐牙菜苦苷在根和花中的积累较多,獐牙菜苷在花中的含量均相对最高。产自青海互助的小秦艽茎、叶和花中獐牙菜苷含量均最高,质量分数分别为2.884%、5.215%和7.321%。研究结果表明:4种环烯醚萜苷成分含量不但与植物种类和器官有关,而且与产地和采样时间也有关。     

滇龙胆与青叶胆环烯醚萜类物质计量特征分析

龙胆科龙胆属滇龙胆(Gentiana rigescens)与獐牙菜属青叶胆(Swertia mileensis)为我国特有种。采用高效液相色谱法测定其中马钱苷酸、獐牙菜苦苷、龙胆苦苷和当药苷含量,结合多变量分析研究环烯醚萜类成分含量及其构成比例在龙胆科植物种内和种间的差异。研究结果显示,4种环烯醚萜类成分的计量特征呈现种间差异,依据环烯醚萜类成分含量及其构成比例,所有滇龙胆样品可分为4类。马钱苷酸含量与纬度呈极显著负相关(R=-0.348,P0.05),与海拔呈极显著正相关(R=0.307,P0.01);獐牙菜苦苷含量与经度呈极显著负相关(R=-0.592,P0.01),高海拔有利于植株中当药苷构成比例的增加(R=0.245,P0.05);地理因子对植株中龙胆苦苷含量变化影响不显著(P0.05)。     

不同生长季节下藏药麻花秦艽活性成分含量研究

采用高效液相色谱法测定了野生与栽培藏药麻花秦艽（Gentiana straminea）根中龙胆苦苷、落干酸、獐牙菜苦苷和獐牙菜苷四种环烯醚萜苷类化学成分的含量及其在不同生长季节的变化趋势。结果表明,4种环烯醚萜苷类成分的含量随植物的生长季节而波动,其活性成分含量在野生种与栽培种之间发生了一定的差异。但是,栽培根中的龙胆苦甙已达到药典的标准,可供药用。     

滇龙胆与青叶胆环烯醚萜类物质计量特征分析?

龙胆科龙胆属滇龙胆( Gentiana rigescens)与獐牙菜属青叶胆( Swertia mileensis)为我国特有种。采用高效液相色谱法测定其中马钱苷酸、獐牙菜苦苷、龙胆苦苷和当药苷含量,结合多变量分析研究环烯醚萜类成分含量及其构成比例在龙胆科植物种内和种间的差异。研究结果显示,4种环烯醚萜类成分的计量特征呈现种间差异,依据环烯醚萜类成分含量及其构成比例,所有滇龙胆样品可分为4类。马钱苷酸含量与纬度呈极显著负相关( R＝－0?348, P<0?05),与海拔呈极显著正相关( R＝0?307, P<0?01);獐牙菜苦苷含量与经度呈极显著负相关( R＝－0?592, P<0?01),高海拔有利于植株中当药苷构成比例的增加( R＝0?245, P<0?05);地理因子对植株中龙胆苦苷含量变化影响不显著( P>0?05)。     

秦艽环烯醚萜苷类成分分离纯化工艺及抑菌活性研究

研究优化XDA-1大孔吸附树脂分离纯化秦艽环烯醚萜苷的最佳工艺,并测试其纯化产物的抑菌活性。以龙胆苦苷的含量为指标,利用动态吸附分离方法,确定秦艽环烯醚萜苷的最佳分离纯化工艺。结果表明XDA-1大孔吸附树脂分离纯化秦艽环烯醚萜苷类化学成分的最佳工艺条件为:上样液浓度0.07 g原药材/mL,pH值为5.0,吸附流速4 BV/h,上样液体积32 BV,洗脱剂浓度50%乙醇溶液,pH值7.0,解吸附流速3 BV/h,洗脱剂用量为8 BV,纯化后环烯醚萜苷含量可达62.97%,并证明了所选的大孔树脂纯化工艺稳定、可靠,值得在生产中推广应用。通过对3种细菌抑菌圈和最小抑菌浓度测定,初步评判该纯化产物的抑菌活性,结果表明,该纯化后产物具有一定的抑菌活性。     

苦龙胆酯苷的研究进展

苦龙胆酯苷是一种裂环烯醚萜苷类化合物,又称为苦龙苷或龙胆苦酯苷。其分子式为:C27H28O14,分子量为576.52,是已知最苦的裂环烯醚萜苷类化合物。目前已证明可从川东獐牙菜、印度獐牙菜、龙胆草以及辐花肋柱花中提取。辐花肋柱花是最新证明的可提取苦龙胆酯苷的植物。苦龙胆酯苷具有助消化,保肝,抗皮肤肿瘤,抗黑热病等药理活性。在古代印度传统医药以及中药藏药中,苦龙胆酯苷的来源植物是治疗消化系统相关疾病的一味常见的草药,如保肝、抗糖尿病等。在体内药代动力学研究中,兔静脉注射苦龙胆酯苷,在血中有较快的清除率(2.62±0.41 L/h/kg)和广泛的体内组织分布(1.08±0.44 L/kg);采用游离、脂质体和囊泡体形式给仓鼠用药具有明显保护肝肾功能且未发现明显不良反应。     

秦艽1-羟基-2-甲基-2-(E)-丁烯基-4-焦磷酸还原酶基因(GmHDR)的克隆和表达分析

龙胆苦苷(gentiopicroside)等裂环烯醚萜苷类化合物是中药秦艽中主要的有效成分,属于萜类化合物的衍生物,1-羟基-2-甲基-2-(E)-丁烯基-4-焦磷酸还原酶(1-hydroxy-2-methyl-2-(E)-butenyl-4-diphosphate reductase,HDR)是植物萜类物质合成的关键酶之一。该研究在实验室高通量测序的基础上,采用RT-PCR方法克隆了秦艽HDR基因(即Gm HDR基因),利用生物信息学的方法分析了Gm HDR编码氨基酸序列的理化性质、信号肽、转运肽、亚细胞定位、保守结构域和高级结构等特征,并采用实时定量PCR分析了HDR的表达模式。结果表明:秦艽Gm HDR基因包含一个完整的长1 392 bp的ORF框,编码463个氨基酸;Gm HDR与萝芙木、艾菊等植物HDR蛋白具有很高的一致性(≥84%),无跨膜结构域,有叶绿体转运肽等结构,主要定位于叶绿体中。实时定量PCR结果显示,Gm HDR基因在秦艽的花中进行表达量高,在叶、茎和根等部位表达较低。Gm HDR在序列上与其他植物的HDR蛋白序列特征上存在很大的相似性;Gm HDR基因主要在秦艽花中表达,可能主要参与花中萜类物质的合成。该研究结果可为今后研究秦艽环烯醚萜类化合物的生物合成机制提供依据。     

川西獐牙菜SmSLS2基因的克隆、生物信息学及表达分析

裂环马钱子苷合成酶（SLS）是环烯醚萜类化合物合成途径的限速酶。该研究根据川西獐牙菜转录组信息获得SmSLS2基因序列,对该基因进行克隆、生物信息分析、原核表达载体构建及蛋白体外诱导。结果表明SmSLS2 cDNA全长1 566 bp（GenBank编号MH535904）,编码521个氨基酸,推测其蛋白相对分子质量为59.79 kDa,等电点为8.92。结构域分析表明SmSLS2含一个跨膜结构域,SmSLS2的gDNA全长为2 576 bp,含5个外显子和4个内含子。SmSLS2蛋白与其他植物中SLS蛋白具有高度的相似性。进一步将SmSLS2构建到原核表达载体pET-28a-sumo上,转入大肠杆菌BL21（DE3）中,在37℃、0.5 mmol·L^-1 IPTG条件下进行原核表达,诱导出与预测蛋白大小一致的目的蛋白。该研究成功从川西獐牙菜中克隆了SmSLS2,为进一步阐明该基因在环烯醚萜合成途径中的作用和通过基因工程手段改良环烯醚萜类化合物产量提供了理论基础。     

西南獐牙菜化学成分的研究

对龙胆科(Gentianaceae)獐牙菜属植物西南獐牙菜(Swertia cincta)进行化学成分研究,从中分离鉴定了15个化合物,包括5个裂环烯醚萜(苷),2个三萜,1个口山酮,4个芳香酸(醇),以及3个其它类成分.以上化合物分别为:獐牙菜苦苷(swertiamarin,1),龙胆苦苷(gentiopicroside,2),红白金花内酯(erythrocentaurin,3),(-)龙胆内酯((-)-gentiolactone,4),angelone(5),齐墩果酸(olcanolic acid,6),3-表-蒲公英赛醇(3-epi-tarax-erol,7),当药醇苷(swertianolin,8),间羟基苯甲醇(m-hydroxybenzyl alcohol,9),邻苯二甲酸二甲酯(dimethyl phthalate,10),邻苯二甲酸二异丁酯(diisobutyl phthalate,11),3,4-二羟基苯甲酸(12)和正三十一烷醇( n-hentria-contanol,13),β-谷甾醇(β-sitosterol,14)和胡萝卜苷(daucosterol,15).其中化合物4-5,7,9～13和15为首次从西南獐牙菜中分离得到.     

坚龙胆中的一个新裂环烯醚萜甙

从坚龙胆（Gentiana rigescens）的根中分离得到1个新的裂环烯醚萜甙,命名为坚龙胆甙A（1）,以及8个已知化合物：龙胆苦甙（2）,6＇-O-β-D-吡喃葡萄糖基-龙胆苦甙（3）,马钱子酸（4）,6＇-O-β-D-吡喃葡萄糖基．马钱子酸（5）,獐牙菜甙（6）,2＇-（邻,间-二羟基苯甲酰基）．獐牙菜甙（7）,獐牙菜苦甙（8）,四乙酰开联番木鳖甙（9）。它们的化学结构通过现代波谱解析得以鉴定。化合物3,5和9为首次从坚龙胆中分离得到。     

植物开花调控途径

开花是植物从营养生长转换为生殖生长的生理发育过程,受光周期、温度、激素、年龄等多个因素诱导,在植物生长和物种进化中处于核心地位。综合不断更新的开花分子遗传结果,将植物响应各种内源和外源信号启动开花的途径归纳为:经典的光周期途径、春化途径、自主途径、赤霉素途径和较新的年龄途径共5条。旨在描绘出这些不同途径间既独立又相互影响的复杂网络关系,为进一步探索和阐述更多植物的开花分子机理提供借鉴与参考。     

拟南芥开花诱导途径分子机制研究进展

拟南芥是分子和遗传学研究的模式植物,对植物花发育及控制花形态建成的分子遗传机制的研究进展主要是建立在对拟南芥研究的基础之上,拟南芥开花主要受到4个途径(自主途径、赤霉素途径、春化作用和光周期途径)的内源和外界信号的同时诱导.该文对近年来国内外有关拟南芥开花诱导的4个途径的分子机制研究进展进行综述,并初步绘制出各开花诱导途径基因间的调控网络图,以进一步明确基因间的相互作用模式及其在整个开花过程中的作用地位.     

Short-term effects of infestation by two aphid species on plant growth and shoot respiration of three legumes

The short-term effects of infestation by cowpea aphids ( Aphis craccivora Koch) and pea aphids [ Acyrthosiphon pisum (Harris)], both Homoptera: Aphididae, on plant growth and respiration of excised, intact shoots of cowpea [ Vigna unguiculata (L.) Walp. cv. Caloona], broad bean ( Vicia faba L. cv. Aquadulce) and garden pea ( Pisum sativum L. cv. Victory Freezer) seedlings were investigated, but not all plant-aphid combinations were utilized. Root, shoot and plant dry weights were significantly reduced within 10 days in the infested plants. Rates of total shoot respiration were significantly greater in infested plants within 10 days, and the increase was not due to increased alternative pathway activity but, rather, to increased cytochrome pathway activity. It is suggested that the aphid-induced increase in shoot respiration may be due to increased rates of photosynthesis, to substances injected into the phloem by the aphids and/or delayed senescence. These data indicate that aphid-infested shoots had a decreased carbon use efficiency.     

Short-term effects of two aphid species on plant growth and root respiration of three leguminous species

The short-term effects of cowpea aphids ( Aphis craccivora Koch) and pea aphids ( Acyrthosiphon pisum Harris), both Homoptera: Aphididae, on plant growth and respiration of excised, intact roots of cowpea [ Vigna unguiculata (L.) Walp. cv. Caloona], broadbean ( Vicia faba L. cv. Aquadulce) and garden pea ( Pisum sativum L. cv. Victory Freezer) seedlings were investigated, but not all plant-aphid combinations were used. Plant and root mean relative growth rates were significantly reduced within 10 days in the infested plants. Rates of total root respiration were was also significantly reduced in all infested plants within 10 days, presumably because of the reduced availability of translocate to the roots. The contribution of the cytochrome pathway to root respiration was significantly greater in control than in infested plants. The activity and engagement of the alternative respiratory pathway was also greater in control plants, and was absent in infested plants after 10 days infestation in all cases but one. These data indicate that the roots of aphid-infested plants were more efficient, in terms of energy conversion, than their respective controls.     

植物萜类化合物的生物合成及应用

萜类化合物是植物中广泛存在的一类代谢产物,在植物生长、发育过程中起重要作用。植物中的萜类化合物有2条合成途径,即甲羟戊酸途径和甲基赤藓糖醇磷酸途径。这2条途径中都存在一系列调控萜类化合物生成、结构和功能各异的酶。植物萜类化合物不仅在植物生命活动中起重要作用,而且具有重要的商业价值,被广泛用于工业、医药卫生等领域。     

Phylogenetic distribution of three pathways for propionate production within the human gut microbiota

Propionate is produced in the human large intestine by microbial fermentation and may help maintain human health. We have examined the distribution of three different pathways used by bacteria for propionate formation using genomic and metagenomic analysis of the human gut microbiota and by designing degenerate primer sets for the detection of diagnostic genes for these pathways. Degenerate primers for the acrylate pathway (detecting the lcdA gene, encoding lactoyl-CoA dehydratase) together with metagenomic mining revealed that this pathway is restricted to only a few human colonic species within the Lachnospiraceae and Negativicutes. The operation of this pathway for lactate utilisation in Coprococcus catus (Lachnospiraceae) was confirmed using stable isotope labelling. The propanediol pathway that processes deoxy sugars such as fucose and rhamnose was more abundant within the Lachnospiraceae (based on the pduP gene, which encodes propionaldehyde dehydrogenase), occurring in relatives of Ruminococcus obeum and in Roseburia inulinivorans. The dominant source of propionate from hexose sugars, however, was concluded to be the succinate pathway, as indicated by the widespread distribution of the mmdA gene that encodes methylmalonyl-CoA decarboxylase in the Bacteroidetes and in many Negativicutes. In general, the capacity to produce propionate or butyrate from hexose sugars resided in different species, although two species of Lachnospiraceae (C. catus and R. inulinivorans) are now known to be able to switch from butyrate to propionate production on different substrates. A better understanding of the microbial ecology of short-chain fatty acid formation may allow modulation of propionate formation by the human gut microbiota.     

白念珠菌MAPK信号通路研究进展

白念珠菌是人类最常见的条件致病菌。促分裂素原活化蛋白激酶（MAPK链）是真核生物信号传递网络中的重要途径之一,在基因表达调控和细胞质功能活动中发挥关键作用。在白念珠菌中主要有4条MAPK途径：Mkcl途径、Cekl途径、Cek2途径和HOG途径。其中HOG途径在白念珠菌MAPK信号通路起着重要的作用。对于白念珠菌MAPK信号通路的作用及相关调控机制的了解,可以为寻找新的药物作用靶点,治疗念珠菌病提供帮助。     

The alternative complement pathway revisited

Alternative pathway amplification plays a major role for the final effect of initial specific activation of the classical and lectin complement pathways, but the quantitative role of the amplification is insufficiently investigated. In experimental models of human diseases in which a direct activation of alternative pathway has been assumed, this interpretation needs revision placing a greater role on alternative amplification. We recently documented that the alternative amplification contributed to 80-90% of C5 activation when the initial activation was highly specific for the classical pathway. The recent identification of properdin as a recognition factor directly initiating alternative pathway activation, like C1q in the classical and mannose-binding lectin in the lectin pathway initiates a renewed interest in the reaction mechanisms of complement. Complement and Toll-like receptors, including the CD14 molecule, are two main upstream recognition systems of innate immunity, contributing to the inflammatory reaction in a number of conditions including ischemia-reperfusion injury and sepsis. These systems act as "double-edged swords", being protective against microbial invasion, but harmful to the host when activated improperly or uncontrolled. Combined inhibition of complement and Toll-like receptors/CD14 should be explored as a treatment regimen to reduce the overwhelming damaging inflammatory response during sepsis. The alternative pathway should be particularly considered in this regard, due to its uncontrolled amplification in sepsis. The alternative pathway should be regarded as a dual system, namely a recognition pathway principally similar to the classical and lectin pathways, and an amplification mechanism, well known, but quantitatively probably more important than generally recognized.     

Evidence of artemisinin production from IPP stemming from both the mevalonate and the nonmevalonate pathways

The potent antimalarial sesquiterpene lactone, artemisinin, is produced in low quantities by the plant Artemisia annua L. The source and regulation of the isopentenyl diphosphate (IPP) used in the biosynthesis of artemisinin has not been completely characterized. Terpenoid biosynthesis occurs in plants via two IPP-generating pathways: the mevalonate pathway in the cytosol, and the non-mevalonate pathway in plastids. Using inhibitors specific to each pathway, it is possible to resolve which supplies the IPP precursor to the end product. Here, we show the effects of inhibition on the two pathways leading to IPP for artemisinin production in plants. We grew young (7–14 days post cotyledon) plants in liquid culture, and added mevinolin to the medium to inhibit the mevalonate pathway, or fosmidomycin to inhibit the non-mevalonate pathway. Artemisinin levels were measured after 7–14 days incubation, and production was significantly reduced by each inhibitor compared to controls, thus, it appears that IPP from both pathways is used in artemisinin production. Also when grown in miconazole, an inhibitor of sterol biosynthesis, there was a significant increase in artemisinin compared to controls suggesting that carbon was shifted from sterols into sesquiterpenes. Collectively these results indicate that artemisinin is probably biosynthesized from IPP pools from both the plastid and the cytosol, and that carbon from competing pathways can be channeled toward sesquiterpenes. This information will help advance our understanding of the regulation of in planta production of artemisinin.     

Induction of an outer membrane protein of 78 kDa in Vibrio vulnificus cultured in the presence of desferrioxamine B under iron-limiting conditions

Fermentation balances and growth yields were determined with various bacteria fermenting lactate to acetate plus propionate either via methylmalonyl-CoA or via acrylyl-CoA. All strains fermented lactate to acetate plus propionate at approximately a 1:2 ratio. Growth yields of Propionibacterium freudenreichii were more than twice as high as those of Clostridium homopropionicum or Veillonella parvula. Hydrogen was formed as a side product to a significant extent only by V. parvula and Pelobacter propionicus; the latter formed hydrogen preferentially when using ethanol as substrate. Acrylyl-CoA reductase of C. homopropionicum and Clostridium neopropionicum was found nearly exclusively in the cytoplasm thus confirming that this reduction step is unlikely to be involved in energy conservation. C. homopropionicum exhibited higher K(S) and higher micro(max) values, as well as higher specific substrate turnover rates than P. freudenreichii. The results allow us to conclude that C. homopropionicum using the acrylyl-CoA pathway with low growth yield obtains its specific competitive advantage compared to P. freudenreichii not through higher substrate affinity or metabolic shift toward enhanced acetate-plus-hydrogen formation but through faster specific substrate turnover.