Identification of Murrayae Folium et Cacumen by Multiplex Allele-Specific PCR / 中国实验方剂学杂志

ObjectiveTo establish a polymerase chain reaction（PCR） method to accurately discriminate the crude materials of Murrayae Folium et Cacumen， Murraya exotica and M. paniculata. MethodBased on the difference in chloroplast genome sequences of M. exotica and M. paniculata， species-specific identification primers P03 and P04 of M. exotica and M. paniculata were designed according to single nucleotide polymorphism （SNP） on the chloroplast genome. A multiplex allele-specific PCR identification method was established for the identification of M. exotica and M. paniculata following the optimization of annealing temperature， number of cycles， and primer concentration ratio. The established PCR method for identification was explored and verified in terms of tolerance and feasibility by investigating the type of Taq polymerases and PCR system model. ResultIn this multiplex allele-specific PCR identification method， about 330 and 230 bp of specific fragments were amplified from DNA templates of M. exotica and M. paniculata， respectively， under the following conditions：cycle number of 31， annealing temperature of 60 ℃， and primer concentration ratio of P03 and P04 of 1∶2. Consistent results were obtained for samples from different sources. ConclusionThe multiplex allele-specific PCR identification method established in this study can accurately identify the origin of Murrayae Folium et Cacumen， which can be used for the simultaneous identification of M. exotica and M. paniculata by the length of fragments in a single identification assay.

Identification of Pheretima by Multiplex Allele-specific PCR / 中国实验方剂学杂志

Objective: In recent years,with the increase in the commodity price of medicinal pheretima,there have emerged increasing adulterates in the medicine market. Besides,the medicinal materials have mostly lost the main identification features, and are difficult to distinguish. Therefore,it is urgent to establish an accurate and stable method for the identification of pheretima. Method: According to the differences of COI gene DNA sequences among Pheretima aspergillum,Pheretima vulgaris,Pheretima guillelmi,Pheretima pectinifera and adulterants,the variation site was found,the specific primers were designed,the reaction conditions were optimized,and the polymerase Chain reaction(PCR) method for identification was explored and verified in terms of tolerance and feasibility in this study. The specific primers were combined to build multiple PCR systems. An effective,accurate,convenient,highly specific and repeatable Multiplex Allele-Specific PCR identification method was established for identifying medicinal pheretima and its common adulterants. Result: Through the established multiplex PCR reaction system, 366,487,487 and 475 bp of fragments were amplified from DNA templates of P. aspergillum,P. vulgaris,P. guillelmi and P.pectinifera respectively. All of the adulterants were negative by the multiplex PCR assay. The PCR amplification of specific alleles method established in this paper can accurately identify pheretima. Conclusion: The Multiplex Allele-Specific PCR identification method established in this paper can accurately identify medicinal pheretima and its adulterants.

Identification of Dendrobium huoshanense, Dendrobium officinale and Dendrobium devonianum by multiplex allele-specific polymerase chain reaction / 药学学报

This study was designed to establish a multiplex allele-specific polymerase chain reaction method for simultaneous identification of Dendrobium huoshanense, D. officinale and D. devonianum, which may resolve identification problems of caulis dendrobii. Internal transcribed spacer sequences and trnL-trnF sequences of the Dendrobium species were aligned by BioEdit software, then specific SNPs of the three species were analyzed for designing allele-specific primers and the multiplex allele-specific PCR reaction system was established. The different origin of Dendrobium huoshanense, D. officinale and D. devonianum was amplified and identified by the sizes of respective band. The results showed that 584 bp, 397 bp and 211 bp bands could be amplified by D. devonianum, Dendrobium officinale and Dendrobium huoshanense respectively, when the annealing temperature was 61 ℃ and the number of cycles was 35. The limit of detection (LOD) of D. devonianum and D. huoshanense were both 1.2 ng, while D. officinale was low than 0.24 ng. The detection limit of adulterates in D. devonianum, D. devonianum and D. huoshanense mixture sample was 1%, 1% and 5% respectively. This result suggests that the method of multiplex allele-specific PCR is useful to identify D. huoshanense, D. officinale and D. devonianum is accurate and specific.

Identification of Panax ginseng, P. notoginseng and P. quinquefolius admixture by multiplex allele-specific polymerase chain reaction / 中国中药杂志

To achieve a molecular method to identify Panax ginseng, P. notoginseng,P. quinquefolius and their admixture. The ITS,18S and matK sequences of Panax genus were analyzed to develop species-specific SNP marker. Three pairs of species-specific primers were designed to establish a multiplex allele-specific polymerase chain reaction (MAS-PCR) and the samples from different region were tested. The results showed that when the annealing temperature was 60 ℃ and the cycle number was 35, approximately 250, 500,1 000 bp specific band were obtained from P. ginseng, P. notoginseng and P. quinquefolius obtain, respectively. This method could also be used to authentificate admixture samples and could detect 0.5% percent of P. notoginseng or P. quinquefolius adulterated in P. ginseng, or 0.5% percent of P. ginseng or P. quinquefolius adulterated in P. notoginseng. The detect limit of P. ginseng in P. quinquefolius was 0.5% and P. notoginseng in P. quinquefolius was 1%. This results showed that the present method could be used as a promise method to identify Panax ginseng, P. notoginseng, P. quinquefolius and their admixture.

A simple, rapid and economic method for detecting multidrug-resistant tuberculosis

OBJECTIVE: To evaluate multiplex allele specific polymerase chain reaction as a rapid molecular tool for detecting multidrug-resistant tuberculosis. METHODS: Based on drug susceptibility testing, 103 isolates were multidrug-resistant tuberculosis and 45 isolates were sensitive to isonicotinylhydrazine and rifampin. Primers were designed to target five mutations hotspots that confer resistance to the first-line drugs isoniazid and rifampin, and multiplex allele specific polymerase chain reaction was performed. Whole-genome sequencing confirmed drug resistance mutations identified by multiplex allele specific polymerase chain reaction. RESULTS: DNA sequencing revealed that 68.9% of multidrug-resistant strains have point mutations at codon 315 of the katG gene, 19.8% within the mabA-inhA promoter, and 98.0% at three hotspots within rpoB. Multiplex allele specific polymerase chain reaction detected each of these five mutations, yielding 82.3% sensitivity and 100% specificity for isoniazid resistance, and 97.9% sensitivity and 100% specificity for rifampin resistance as compared to drug susceptibility testing. CONCLUSIONS: The results show that multiplex allele specific polymerase chain reaction is an inexpensive and practical method for rapid detection of multidrug-resistant tuberculosis in developing countries.