Overexpressing of chalcone isomerase (CHI) gene enhances flavonoid accumulation in Glycyrrhiza uralensis hairy roots / 药学学报

Chalcone isomerase (CHI) is the second rate-limiting enzyme involved in the biosynthetic pathway of flavonoids in Glycyrrhiza uralensis. Based on our previous studies, we selected the specific CHI haplotype (GenBank Accession No. KY115232) to maximize flavonoid accumulation. We constructed a plant binary expression vector for overexpression of this CHI gene by the gene fusion method and transfected the plasmid into Agrobacterium tumefaciens ACCC10060 by electroporation. The recombinant A. tumefaciens ACCC10060 subsequently was used to infect cotyledons and hypocotyls of G. uralensis to obtain transgenic hairy roots. A qRT-PCR method was used to determine the copy number of CHI and a UPLC method was used to assay the content of four flavonoids in different hairy root lines. The qRT-PCR results showed that the copy number of CHI in hairy roots was 1 or 5. UPLC results showed that the content of total flavonoids, liquiritin, liquiritigenin, and isoliquiritigenin in transgenic hairy root samples was significantly higher than that in wild-type samples. This study demonstrates that overexpression of CHI significantly increases the content of flavonoids in hairy roots of G. uralensis. This work provides a theoretical basis for clarifying the function of CHI. Three transgenic hairy root lines of G. uralensis were isolated which can be used to increase the accumulation of licorice flavonoids in vitro.

Over-expressing root-specific β-amyrin synthase gene increases glycyrrhizic acid content in hairy roots of glycyrrhiza uralensis / 中草药·英文版

Objsective: Glycyrrhizia uralensis, one of the most widely-used traditional Chinese medicines, is mainly cropped in China. However, many cultivars are less in glycyrrhizic acid than Chinese Pharmacopoeia requires. In this paper, we improved glycyrrhizic acid by regulating β-amyrin synthase gene (GuBAS). Methods: Tobacco root-specific promoter TobRB7 and GuBAS cDNA were obtained and combined with linearized pCAMBIA1305.1 to construct root-specific plant expression vector which was later transformed into Agrobacterium rhizogenes ACCC10060 by electrotransformation. The cotyledons and hypocotyls of G. uralensis were infected by the recombinant A. rhizogenes ACCC10060 to induce hairy roots. The GA content was quantified by HPLC. Results: The PCR and sequencing results both showed that three transgenic hairy root lines were obtained. The copy number of GuBAS in these transgenic hairy roots was intended by qRT-PCR to be 3, 7, and 4. GA was detected by HPLC, and the results showed that GA was present in the three transgenic hairy roots, while absent in wild hairy roots. Conclusion: Over-expressing GuBAS root-specifically in hairy roots of G. uralensis enhanced GA accumulation.

Analysis on the correlation between chalcone synthase gene polymorphism and content of liquiritin in licorice / 药学学报

Chinese pharmacopoeia stipulates that the content of liquiritin in licorice slices should be no less than 0.5%. However, there are lots of unqualified licorice slices in the herbal medicine markets. Due to the important role of functional gene polymorphism in secondary metabolism, this study attempts to analyze the influence of chalcone synthase (CHS) gene polymorphism on liquiritin biosynthesis and find out the unique haplotypes in licorice samples with high or low content of liquiritin, and to provide a basis for further analysis of molecular mechanism in flavonoid biosynthetic pathway. The contents of the 4 main flavonoids (liquiritin, isoliquiritin, liquiritigenin, isoliquiritigenin) in 60 licorice samples were assayed by HPLC and the results were analyzed by Spearman and χ2 tests. The contents of the 4 main flavonoids were related to each other and obviously different in different original plants. They were highest in Glycyrrhiza uralensis samples and lowest in Glycyrriza inflate samples. Five G. uralensis samples with the highest liquiritin contents and five G. inflate samples with the lowest liquiritin contents were selected to clone the CHS cDNA sequences. 336 CHS cDNA sequences with a full length of 1 175 bp were obtained, 249 variable sites (141 missense mutation sites) were found, and 137 haplotypes were determined. 130 variable sites were found in the 336 CHS amino acid sequences and 102 types were determined. AA-3 is the major type of CHS in licorice, AA-35 is the special major type of CHS in the group with high flavonoids contents and AA-36 is the special major type of CHS in the group with low flavonoids contents. The mutation sites between AA-35 and AA-36 are I/V at 193 and V/T at 229. Discovery Studio 2.5 analysis of the three-dimensional structure of the CHS protein shows that the valine at site 229 of AA-35 is combined with malonyl-CoA. Homology analysis indicates that the homology of CHS among different species is low. This study is significant for identification of the unique haplotypes in licorices with high or low content of liquiritin and guiding the further molecular breeding of high-quantity licorice.

Development of the digital-display medical oxygen discharge and time measuring / 中国医疗器械杂志

A develop of medical discharger of oxygen is presented in the paper. The medical discharge can control, display and print the output data including the time, oxygen discharge the total time and the total oxygen discharge of two channels oxygen synchronously or respectively, Results show that the device is of reasonable design, accurate, measurement simple operation, low cost, real-time display, alarm and controlling the channels oxygen automatically and can print data if necessary. It will be widely used in clinic.