Authentication of medicinal Dendrobium species by the internal transcribed spacer of ribosomal DNA

Herba Dendrobii (Shihu) is a commonly used Chinese medicine derived from the stem of several orchid species belonging to the genus Dendrobium. It is rather expensive and adulteration is frequent. Proper authentication of the medicinal species is necessary to protect consumers and support conservation measures. DNA sequences of the internal transcribed spacer 2 (ITS 2) of 16 Dendrobium species were shown to be significantly different from one another by an average of 12.4% and from non-orchids and Pholidota (an adulterant of Shihu) by 29.8% and 18.8%, respectively. The intra-specific variation among the Dendrobium species studied was only about 1%. Therefore, ITS 2 regions could be adopted as a molecular marker for differentiating medicinal Dendrobium species from one another and also from non-orchids and adulterants.     

Differentiation of Dendrobium species used as "Huangcao Shihu" by rDNA ITS sequence analysis

The genus Dendrobium Sw. is composed of 74 species and two varieties in China, and 32 species carry the name "Huangcao Shihu" on the herbal medicine market, making the identification of the origin of "Huangcao Shihu" difficult for consumers. Here, the ITS regions were sequenced and evaluated to differentiate the 18 Dendrobium species used as "Huangcao Shihu". Diversity in DNA sequences among various species was found with the inter-specific sequence divergence ranging from 3.2% to 37.9% in ITS1 and 5.0% to 26.6% in ITS2. Moreover, the variations within species were very low, ranging in sequence divergence from 0 to 3.0% in ITS1 and 0 to 4.0% in ITS2. Therefore, these species could be easily distinguished at the DNA level. Furthermore, based on the divergent ITS regions, five pairs of species-specific primers were designed and used for the rapid PCR identification of five Dendrobium species listed in the Chinese Pharmacopoeia.     

中药材蒲公英及其混淆品的DNA指纹鉴别研究

采用分子生物技术包括任意引物聚合酶链式反应（AP－PCR）和随意扩增多态性DNA（RAPD）方法扩增蒲公英及其六种土公英混淆品的基因组DNA，获得清晰可靠的DNA指纹图谱。根据琼脂糖胶上显示的DNA带型差异可鉴别蒲公英和土公英混淆品。     

花椒及其混淆品的rDNA ITS区序列分析与鉴别

目的研究不同居群的花椒及其混淆品的rDNA ITS区碱基序列的特征及其差异，为花椒的鉴别提供可靠的分子标记。方法运用PCR产物直接测序和克隆测序法对甘肃、陕西、四川、河北等7个花椒居群及3个混淆种的rDNA ITS区(包括ITS1，5.8S，ITS2)碱基序列进行序列测定。结果首次报道花椒ITS区的碱基序列，序列总长度为619-620 bp，长度变异较少，与混淆种长度仅相差4 bp。花椒各居群中，rDNA ITS区碱基序列有15个变异位点、12个信息位点、3个特异性识别位点。与混淆品间的碱基差异则较为显著，多达71个变异位点，有4个花椒特异性识别位点。结论依据花椒ITS区的序列特征可准确鉴别各居群的花椒及其混淆品；亲缘关系密切的花椒居群在地理位置上也非常靠近；rDNA ITS序列特征可作为花椒种内和种间鉴别的有效分子标记。     

Molecular authentication of the traditional Tibetan medicinal plant Swertia mussotii

Swertia mussotii is an important species in Tibetan folk medicine. However, it is quite expensive and frequently adulterated, so reliable methods for authentication of putative specimens and preparations of the species are needed to protect consumers and to support conservation measures. We show here that the chloroplast (cp) DNA RPL16 intron has limited utility for differentiating S. mussotii from closely related species, since the cpDNA RPL16 sequences are identical in S. mussotii and two other species of Swertia. However, the rDNA internal transcribed spacer (ITS) sequences differ significantly between S. mussotii and all of 13 tested potential adulterants. Thus, the ITS region provides a robust molecular marker for differentiating the medicinal S. mussotii from related adulterants. Therefore, a pair of allele-specific diagnostic primers based on the divergent ITS region was designed to distinguish S. mussotii from the other species. Authentication by allele-specific diagnostic PCR using these primers is convenient, effective and both simpler and less time-consuming than sequencing the ITS region.     

Authentication of stems of Dendrobium officinale by rDNA ITS region sequences

The rDNA ITS regions of five Dendrobium species were sequenced. Each Dendrobium species was found to have a unique sequence in the ITS region, so that they could be easily distinguished at the DNA level. The aligned 644 bp of the ITS region includes 235 bp ITS1, 163 bp 5.8S, and 246 bp ITS2. One hundred and eighty-nine sites are variable. The sequences of D. officinale could be easily distinguished from the other four adulterant species according to the sequence variation at 11 sites, 7 in ITS1, 1 in 5.8S, and 3 in ITS2. These could be used as molecular characters to distinguish the stems of D. officinale from the adulterants.     

ITS2+psbA-trnH复合序列鉴定徐长卿、白薇和白前

目的：建立以ITS2+psbA-trnH复合序列鉴定徐长卿、白薇和白前及其同属近缘混伪品的DNA条形码鉴定方法。方法：搜集徐长卿、白薇、白前及其近源混伪品,采用改良的CTAB法提取DNA,通过实验分别获得ITS2和psbA-trnH序列,将同一样本的ITS2序列与psbA-trnH序列整合得到43条ITS2+psbA-trnH复合序列,从GenBank数据库中下载来源于同一样本的ITS2序列与psbA-trnH序列整合得到14条ITS2+psbA-trnH 网上复合序列,用MEGA 6.05软件分析徐长卿、白薇、白前及其近源混伪品的复合序列变异位点,计算种内、种间的K2P距离,并构建NJ系统聚类树。结果：徐长卿、白薇和白前药材ITS2+psbA-trnH复合序列比对后产生17个变异位点;徐长卿、白薇和白前基源物种种内最大K2P距离均小于其与混伪品的种间最小K2P距离;系统NJ树能准确将徐长卿白薇和白前及其近缘混伪品。结论：该研究建立了应用ITS2+psbA-trnH复合序列鉴定徐长卿、白薇、白前及其近缘混伪品的DNA条形码鉴定方法。     

基于matK和ITS2及二级结构对药材香薷及其混伪品的鉴别研究

目的 快速、准确鉴别药材香薷及其混伪品，保障香薷的药材质量和用药安全。方法 收集石香薷、江香薷和香薷植物材料分别进行matK和ITS2序列的扩增与测序，测序结果经Codon Code Aligner软件校对，同时从GenBank下载石香薷、江香斋及其易混品种海州香薷、香薷、密花香薷、牛至等物种的matK和ITS序列。其中，ITS序列经隐马尔可夫模型去除两端的5.8S和28S序列，共得到16个物种的ITS2序列50条；经Clustal软件校对共获得9个物种的matK序列28条。通过Mega7.0软件分析matK和ITS2序列，计算所有物种种内和种间遗传距离，构建邻接法(neighbor joining，NJ)聚类树，通过ITS2 Database预测ITS2二级结构，采用4Sale软件比对二级结构，通过ProfDistS软件构建基于联合ITS2一级序列及其二级结构的剖面邻接(profile neighbor-joining，PNJ)系统发育树。结果 基于matK和ITS2序列的遗传距离均表明香薷正品与其各种混伪品之间存在明显barcoding gap。NJ和PNJ进化树的拓扑关系一致，可以区分药材香薷及其混伪品。香薷的ITS2二级结构与其各混伪品具有显著差异。结论 建议matK和ITS2序列均可以作为鉴别香薷与其混伪品的DNA条形码，ITS2二级结构信息的加入可丰富鉴定结果，为香薷药材的准确鉴别、香薷属与石荠苎属植物的科学分类提供参考。     

DNA条形码鉴定洋金花及其伪品

为建立有毒中药洋金花及其伪品DNA条形码鉴定方法,采用国际通用的条形码序列ITS2、psbA-trnH、matK和rbcL对洋金花原植物白花曼陀罗及其伪品毛曼陀罗、曼陀罗和木本曼陀罗4个种共计20份材料进行了比较研究。PCR及测序成功率分别为ITS2(100%)、matK(100%)、psbA-trnH(90%)、rbcL(85%)。采用CodonCode Aligner进行序列拼接,采用MEGA 4.1计算白花曼陀罗及其伪品的种内、种间的K2P距离,并基于K2P模型构建NJ树。结果显示ITS2序列共有30个单核苷酸多态性(SNPs)位点、psbA-trnH序列有33个单碱基的插入和缺失I。TS2和psbA-trnH序列种间遗传距离大于种内,matK和rbcL种内和种间没有明显Barcoding Gap。4个条形码序列及其组合获得的分子系统树(ITS2、psbA-trnH、matK、rbcL、matK+rbcL)均分成了两大支,木本曼陀罗单聚为一支,该分子证据支持将Brugmansia提升为属水平。实验结果表明ITS2及psbA-trnH序列可以作为洋金花及其伪品鉴定用的条形码序列。     

基于ITS序列鉴别特色民族药材土牛膝及其混伪品的研究

目的:利用DNA条形码对特色民族药材土牛膝(粗毛牛膝、野生牛膝和柳叶牛膝)及其混伪品进行分子鉴定.方法:利用DNA条形码方法,分别对土牛膝及其混伪品的ITS和MatK基因片段进行扩增并双向测序,使用Codon?Code?Aligner软件对扩增序列进行拼接,用MEGA软件对数据比对分析,并基于K2P模型进行遗传距离分析...     

Differentiation of the traditional Chinese medicinal plants Euphorbia humifusa and E. maculata from adulterants by TaqMan real-time polymerase chain reaction

DNA sequence analysis of the rDNA internal transcribed spacer 1 (ITS1) and TaqMan real-time polymerase chain reaction were exploited for their applications in the differentiation of the traditional chinese medicinal plants euphorbia humifusa and e. maculata from three related adulterants e. hypericifolia, E. atoto and E. prostrata. The data demonstrated that variations in the ITS1 regions were very low at the intra-species level but extremely high at the inter-species level, so that they could be easily distinguished at the DNA level. The sequence difference allowed an effective and reliable differentiation of E. humifusa and E. maculata from the adulterants by TaqMan real-time PCR.     

A molecular marker that is specific to medicinal rhubarb based on chloroplast trnL/trnF sequences.

"Da-Huang" (Radix et Rhizoma Rhei, medicinal rhubarb), a famous and important Traditional Chinese Medicine, has often been confused with the adulterant species in the same genus, Rheum. Through sequencing the trnL (UAA)/trnF (GAA) regions of chloroplast DNA of thirteen species of Rheum (three medicinal rhubarb species and ten adulterant ones), a molecular marker of the medicinal species was found. A pair of PCR primers based on the sequences, was thus designed, which amplified a highly specific DNA fragment in medicinal rhubarb exclusively, and absent in the adulterants at all under an optimized PCR condition.     

Use of the potential DNA barcode ITS2 to identify herbal materials

A potential DNA barcode, ITS2, was studied to discriminate herbal materials to confirm their identities and ensure their safe application in pharmaceuticals. Here, a total of 4385 samples of 2431 species were collected, and these samples are from 61 commonly used herbs and their closely related species or adulterants. Based on assessments of the extent of genetic divergence, the DNA barcoding gap and the ability for species discrimination, our results suggest that ITS2 is a powerful tool for distinguishing herbs. For the first dataset including 61 herbs, ITS2 correctly identified 100 % of them. For the second dataset containing 51 herbs and their 2382 closely related species, ITS2 could discriminate correctly 48 herbs from their closely related species. For the third dataset comprising 34 herbs and their 111 adulterants, ITS2 could distinguish successfully all the herbs from their adulterants. In conclusion, the ITS2 region is an efficient marker for the authentication of herbal materials, and our study will accelerate the process of the application of the DNA barcoding technique in differentiating herbs.     

重楼属药用植物DNA条形码鉴定研究

为评价DNA条形码候选序列对重楼属药用植物的鉴定作用, 探讨重楼属药用植物鉴定新方法, 本研究对重楼属11个物种17份样品的psbA-trnH、rpoB、rpoC1、rbcL、matK和核ITS2序列进行PCR扩增和测序, 比较各序列扩增和测序效率、种内和种间变异, 进行barcoding gap分析, 采用BLAST1和Nearest Distance方法评价不同序列的鉴定能力。结果显示, ITS2序列在所研究的重楼属药用植物中的扩增和测序效率均为100%, 其种内种间变异、barcoding gap与其他DNA条形码候选序列相比具有明显的优势, ITS2序列在重楼属中的鉴定成功率达到100%, 而生物条形码协会 (CBOL) 植物工作组推荐的matK和rbcL序列的鉴定成功率分别为52.9% 和5.9%, 二者联合鉴定能力没有提高, 对于ITS2序列扩大至29个物种67份样品依然具有100%的鉴定成功率。实验结果表明, ITS2序列能够准确鉴定重楼属药用植物, 可以作为潜在的药用植物通用条形码序列。     

基于DNA条形码技术鉴定蒙药材刺柏叶及其混淆品

目的：基于DNA条形码技术鉴别蒙药材刺柏叶及其混淆品。方法：采用国际通用的条形码序列 ITS2、psbA-trnH、matK和rbcL,对刺柏叶及其混淆品圆柏叶共计11份样品进行DNA提取、扩增,采用CodonCode Aligner进行序列拼接,并用MEGA软件对拼接序列进行变异位点分析、邻接(NJ)聚类分析,并计算其平均种内、种间遗传距离。结果：4对引物的PCR扩增产物测序成功率分别为ITS2 100%、 psbA-trnH 100%、rbcL 100%、matK 0%;ITS2序列和psbA-trnH序列均可通过变异位点比较区分刺柏叶及其混淆品;NJ聚类分析的结果显示,psbA-trnH序列的NJ聚类树中刺柏叶与圆柏叶均能分别聚为一支,且psbA-trnH序列的平均种间遗传距离明显大于平均种内遗传距离。结论：psbA-trnH序列能有效区分圆柏叶与刺柏叶,可作为鉴别刺柏叶及其混淆品圆柏叶的条形码序列,为蒙药材刺柏叶及其混淆品的鉴别提供支持。     

Species identification of medicinal pteridophytes by a DNA barcode marker, the chloroplast psbA-trnH intergenic region

Medicinal pteridophytes are an important group used in traditional Chinese medicine; however, there is no simple and universal way to differentiate various species of this group by morphological traits. A novel technology termed "DNA barcoding" could discriminate species by a standard DNA sequence with universal primers and sufficient variation. To determine whether DNA barcoding would be effective for differentiating pteridophyte species, we first analyzed five DNA sequence markers (psbA-trnH intergenic region, rbcL, rpoB, rpoC1, and matK) using six chloroplast genomic sequences from GeneBank and found psbA-trnH intergenic region the best candidate for availability of universal primers. Next, we amplified the psbA-trnH region from 79 samples of medicinal pteridophyte plants. These samples represented 51 species from 24 families, including all the authentic pteridophyte species listed in the Chinese pharmacopoeia (2005 version) and some commonly used adulterants. We found that the sequence of the psbA-trnH intergenic region can be determined with both high polymerase chain reaction (PCR) amplification efficiency (94.1%) and high direct sequencing success rate (81.3%). Combined with GeneBank data (54 species cross 12 pteridophyte families), species discriminative power analysis showed that 90.2% of species could be separated/identified successfully by the TaxonGap method in conjunction with the Basic Local Alignment Search Tool 1 (BLAST1) method. The TaxonGap method results further showed that, for 37 out of 39 separable species with at least two samples each, between-species variation was higher than the relevant within-species variation. Thus, the psbA-trnH intergenic region is a suitable DNA marker for species identification in medicinal pteridophytes.     

甘草与海藻 大戟 芫花配伍对大鼠肝脏CYP2E1酶活性及mRNA表达的影响

目的研究甘草与海藻、大戟、芫花合用对CYP2E1酶活性的影响及在mRNA水平的调控作用。方法采用高效液相色谱法测定CYP2E1活性;采用反转录聚合酶链反应(RT-PCR)评价药物对CYP2E1 mRNA水平的影响。结果甘草单用能明显诱导CYP2E1酶活性,与海藻、大戟、芫花合用后对CYP2E1酶活性的诱导作用没有甘草单用明显。CYP2E1 mRNA水平基本与酶活性水平相平行。结论甘草与海藻、大戟、芫花合用后诱导CYP2E1酶活性,酶活性变化可能主要通过影响基因转录来实现。     

Allele-specific primers for diagnostic PCR authentication of Dendrobium officinale

Based on rDNA ITS sequences of D. officinale and the other 37 species of Dendrobium, a pair of allele-specific diagnostic primers, TP-JB01S and TP-JB01X, were designed to authenticate D. officinale from the other species. Before the diagnostic PCR, the primer pair, P1 and P2, for amplifying the whole ITS region was used to validate template DNA and to obtain the appropriate template DNA for the diagnostic PCR. Diagnostic PCRs were performed using the diagnostic primers with the total DNAs of the original plants as a template. When the annealing temperature was raised to 66 degrees C, only the template DNA of D. officinale could be amplified whereas the diagnostic PCRs of the other Dendrobium species were all negative. The diagnostic PCRs have been repeated many times and have played an important role in authenticating the stems of D. officinale in China. Compared with the authentication method by sequencing DNA fragments, the allele-specific diagnostic PCR is not only simpler and time-saving but also practical and effective.     

球花石斛的位点特异性PCR鉴别研究

为建立球花石斛的DNA分子标记鉴别方法，本文根据测定及GenBank上登录的109种共计164个石斛样本的rDNA ITS序列，设计了特异性鉴别引物QH-JB1 和QH-JB2，并对球花石斛进行了位点特异性PCR鉴别研究。结果表明，当复性条件为63.5 ℃，1 min时，只有球花石斛的模板DNA能被扩增出约300 bp的阳性扩增带，而其他种石斛均为阴性。证明用本法鉴别球花石斛简便、省时，也适用于干燥球花石斛药材的鉴别，具有广泛的应用前景。     

市售覆盆子药材DNA条形码鉴定研究

目的基于ITS2条形码序列检测市场销售覆盆子药材,为保证覆盆子药材使用的正确性和安全性提供一种新的鉴定手段。方法获取掌叶覆盆子及其5种常见同属易混种ITS2序列,以及GenBank上下载的共计48条序列。使用Gene Tool软件分析ITS2序列长度,GC含量和变异位点等情况,利用Clustal X和MEGA 7.0软件计算遗传距离和构建邻接系统发育聚类树。同时随机检测24份市售覆盆子药材,利用中药材DNA条形码鉴定系统和构建邻接系统发育聚类树确定物种,鉴别真伪。结果掌叶覆盆子基原植物可与其同属易混种进行明显区分;市售药材中正品22份,伪品1份,混合物1份。结论基于ITS2序列的DNA条形码技术能够成功鉴定市场销售的掌叶覆盆子及其混伪品。