Cloning and characterization of a cDNA encoding beta-amyrin synthase involved in glycyrrhizin and soyasaponin biosyntheses in licorice.

An oxidosqualene cyclase cDNA, termed GgbAS1, was isolated from cultured cells of licorice (Glycyrrhiza glabra) by heterologous hybridization with cDNA of Arabidopsis thaliana LUP1 lupeol synthase. The yeast transformed with an expression vector containing the open reading frame of GgbAS1 produced beta-amyrin, indicating that GgbAS1 encodes beta-amyrin synthase involved in the glycyrrhizin and soyasaponin biosyntheses in licorice. Northern blot analysis showed that the level of beta-amyrin synthase mRNA was drastically changed in the cultured licorice cells, whereas the mRNA level of cycloartenol synthase was relatively constant.

Identification of the crude drug atractylodes rhizome (Byaku-jutsu) and atractylodes lancea rhizome (So-jutsu) using chloroplast TrnK sequence as a molecular marker.

Novel methods for molecular authentication of Atractylodes-derived crude drugs (Jutsu) were established based on PCR-restriction fragment length polymorphism (RFLP) and direct sequencing of chloroplast trnK. Two regions inside the chloroplast trnK were selected as molecular markers for identification and discrimination of Atractylodes Rhizome (Byaku-jutsu) and Atractylodes Lancea Rhizome (So-jutsu). The Region 1 fragment (260 bp) amplified from So-jutsu and Wa-byaku-jutsu (Atractylodes Rhizome derived from A. japonica) gave 2 bands of 180 bp and 80 bp on agarose gel electrophoresis after digestion with a restriction endonuclease HinfI, whereas the fragment amplified from Kara-byaku-jutsu (Atractylodes Rhizome derived from A. ovata) remained undigested, which allowed unambiguous identification of Kara-byaku-jutsu. By direct sequencing of Region 2 (436 bp) and comparison of the nucleotide sequence data sets we could not only discriminate Byaku-jutsu and So-jutsu but also identify the original plant species of each crude drug specimen. A simple and reliable protocol for rapid preparation of DNA suitable for PCR from as little as 1 mg of Atractylodes-derived crude drugs was also described.

Phylogenetic relationship of six Glycyrrhiza species based on rbcL sequences and chemical constituents.

The nucleotide sequences of ribulose-1,5-bisphosphate carboxylase/oxygenase large subunit gene (rbcL) of Glycyrrhiza glabra, G. uralensis, G. inflata, G. echinata, G. macedonica and G. pallidiflora have been determined to construct their phylogenetic tree. Based on these sequences, the six Glycyrrhiza species were divided into two groups: three, G. glabra, G. uralensis, and G. inflata, which produce glycyrrhizin as a major saponin, and the others, G. echinata, G. macedonica and G. pallidiflora, which produce macedonoside C as a major saponin. Among the three glycyrrhizin-producing species, only two nucleotide substitutions were observed between the rbcL sequences of G. glabra and G. uralensis, and the sequence of G. uralensis was identical to that of G. inflata, indicating that G. uralensis and G. inflata are closely related. Among the three macedonoside C-producing species, only one nucleotide substitution was observed between those of G. echinata and G. macedonica, indicating that these two species are also closely related.

Molecular cloning and expression of two distinct human chondroitin 4-O-sulfotransferases that belong to the HNK-1 sulfotransferase gene family.

Using an expression cloning strategy, the cDNA encoding the human HNK-1 sulfotransferase (HNK-1ST) has been cloned. During this cloning we found that HNK-1ST and other Golgi-associated sulfotransferases cloned before share homologous sequences including the RDP motif (Ong, E., Yeh, J.-C., Ding, Y., Hindsgaul, O., and Fukuda, M. (1998) J. Biol. Chem. 223, 5190-5195). Using this conserved sequence in HNK-1ST as a probe, we identified two expressed sequence tags in EST data base which have 31.6 and 30.7% identity with HNK-1ST at the amino acid levels. Expression of these two full-length cDNAs failed to form HNK-1 glycan nor to add sulfate to CD34 or NCAM. Surprisingly, proteins expressed by these cDNAs transferred sulfate to the C-4 position of N-acetylgalactosamine in chondroitin and desulfated dermatan sulfate, thus we named these two enzymes, chondroitin 4-O-sulfotransferase 1 and -2 (C4ST-1 and C4ST-2). Both C4ST-1 and C4ST-2, however, did not form 4, 6-di-O-sulfated N-acetylgalactosamine when chondroitin sulfate C was used as an acceptor. Moreover, analysis of (35)S-labeled dermatan sulfate formed by C4ST-1 indicate that sulfation preferentially took place in GlcA-->GalNAc unit than in IdoA-->GalNAc unit, suggesting that 4-O-sulfation at N-acetylgalactosamine may precede epimerization of glucuronic acid to iduronic acid during dermatan sulfate biosynthesis. Northern analysis demonstrated that the transcript for C4ST-1 is predominantly expressed in peripheral leukocytes and hematopoietic tissues while the C4ST-2 transcript is more widely expressed in various tissues. These results indicate C4ST-1 and C4ST-2 play complementary roles in chondroitin and dermatan sulfate synthesis in different tissues.

Molecular cloning and characterization of a cDNA for Glycyrrhiza glabra cycloartenol synthase.

A cDNA clone (GgCAS1) encoding cycloartenol synthase (CAS) has been isolated from Glycyrrhiza glabra (licorice) by cross-hybridization with that of Pisum sativum CAS as a probe. The deduced amino acid sequence of GgCAS1 exhibits 89%, 83% and 81% identity to those of Pisum sativum, Panax ginseng and Arabidopsis thaliana CASs, respectively. CAS activity has been detected in the homogenate of the yeast transformed with the expression vector containing the open reading frame of GgCAS1. Southern blot analysis suggested that at least two CAS genes exist in the licorice genome. In Northern blot analysis, the strong signal for CAS mRNA is detected in the cultured licorice cells of all growth phases, but no significant increase of CAS mRNA expression was observed in the cells treated with the 3-hydroxy-3-methylglutaryl-CoA reductase inhibitor, pravastatin.

Molecular cloning and characterization of two cDNAs for Glycyrrhiza glabra squalene synthase.

Two cDNAs (GgSQS1 and GgSQS2) encoding squalene synthase have been isolated from licorice, Glycyrrhiza glabra L., and characterized. The deduced amino acid sequence of GgSQS1 was 88%, 81%, 78%, 45-44%, and 45-41% identical to those of GgSQS2, Nicotiana, Arabidopsis, mammal and yeast squalene synthases, respectively. Squalene synthase activity was found in the cell-free extracts of Escherichia coli transformed with the recombinant plasmids for GgSQS1 and GgSQS2, respectively. Genomic Southern blot hybridization indicated that there are three squalene synthase genes in the licorice genome. Northern blot analysis showed that GgSQS2 mRNA is mainly expressed during the exponential growth phase of the cultured licorice cells.

A novel, high endothelial venule-specific sulfotransferase expresses 6-sulfo sialyl Lewis(x), an L-selectin ligand displayed by CD34.

L-selectin mediates lymphocyte homing by facilitating lymphocyte adhesion to unique carbohydrate ligands, sulfated sialyl Lewis(x), which are expressed on high endothelial venules (HEV) in secondary lymphoid organs. The nature of the sulfotransferase(s) that contribute to sulfation of such L-selectin counterreceptors has been uncertain. We herein describe a novel L-selectin ligand sulfotransferase, termed LSST, that directs the synthesis of the 6-sulfo sialyl Lewis(x) on L-selectin counterreceptors CD34, GlyCAM-1, and MAdCAM-1. LSST is predominantly expressed in HEV and exhibits striking catalytic preference for core 2-branched mucin-type O-glycans as found in natural L-selectin counterreceptors. LSST enhances L-selectin-mediated adhesion under shear compared to nonsulfated controls. LSST therefore corresponds to an HEV-specific sulfotransferase that contributes to the biosynthesis of L-selectin ligands required for lymphocyte homing.

Seasonal variation of glycyrrhizin and isoliquiritigenin glycosides in the root of Glycyrrhiza glabra L.

The time courses of the glycyrrhizin and isoliquiritigenin glycoside contents in the thickening roots of licorice, Glycyrrhiza glabra L., have been determined. The glycyrrhizin content in 1-year-old roots rapidly increased from October to November, whereas the isoliquiritigenin glycoside content increased up to October. In 3-year-old plants, although the isoliquiritigenin glycoside content rapidly increased from June to July, the glycyrrhizin content did not show any significant increase from May to August. The glycyrrhizin content increased during the senescence of the aerial parts as well as during the early stage of shoot elongation. The incorporation of [14C]mevalonic acid into the glycyrrhizin fraction by the root segments was high in May, June and September, and low in August and winter. These results indicated that the biosynthesis of glycyrrhizin is differently regulated from that of isoliquiritigenin glycoside in the thickening root of G. glabra.

Phylogenetic relationship of Glycyrrhiza plants based on rbcL sequences.

The nucleotide sequences of the ribulose-1,5-bisphosphate carboxylase/oxygenase large subunit gene (rbcL) of Glycyrrhiza glabra, G. uralensis, G. inflata, G. echinata, and G. pallidiflora have been determined to construct the phylogenetic tree. In the phylogenetic tree based on the rbcL sequences, the five Glycyrrhiza species were divided into two groups: the three glycyrrhizin-producing species G. glabra, G. uralensis, and G. inflata; and the two glycyrrhizin-nonproducing species G. echinata and G. pallidiflora. Among the three glycyrrhizin-producing species, only two nucleotide substitutions were observed between the rbcL sequence of G. glabra and G. uralensis, and the sequence of G. uralensis was identical to that of G. inflata, indicating that the three glycyrrhizin-producing species are closely related.

Atractylodes lancea autotetraploids induced by colchicine treatment of shoot cultures.

Two strains of autotetraploid plants of Atractylodes lancea DC. (Compositae) were raised from the in vitro colchicine-treated shoot cultures, and field trials were performed to evaluate their growth and the amount of essential oil components in the rhizome in comparison with the corresponding diploids. The tetraploid plants had larger leaves than the diploids. One of the selected tetraploid lines had about 1.5 times as heavy rhizomes as the diploid and contained atractylodin, hinesol and beta-eudesmol in the rhizome to as great an extent or slightly less than the diploids. However, the contents of these constituents in the rhizome of the other tetraploid strain were lower than the diploids. The chloroplast number per guard cell, stomatal length, and stomatal density of leaf lower epidermis of the shoot cultures were good indicators for distinguishing tetraploids from diploids.

Phylogenetic analysis of Atractylodes plants based on chloroplast trnK sequence.

The phylogenetic relationship of Atractylodes lancea, A. chinensis, A. koreana, A. ovata and A. japonica were analyzed by comparing the 2.6 kb sequence in a chloroplast gene trnK encoding tRNALys (UUU). The dried rhizomes of the former three species have been used as the crude drug "So-jutsu" and those of the latter two as "Byaku-jutsu" in Chinese and Japanese traditional medicine ("Kampo-medicine"). The trnK phylogenetic tree revealed that A. ovata is an outgroup of the five Atractylodes species examined and that A. japonica and A. lancea are most closely related. PCR amplification of trnK with HinfI digestion provided us with a simple method to distinguish A. ovata from other Atractylodes species at the molecular level.

Induction of furanocoumarin biosynthesis in Glehnia littoralis cell suspension cultures by elicitor treatment.

Cell suspension cultures were established from Glehnia littoralis plants belonging to two different geographic strains. When the cells were treated with yeast extract, they started to produce and excrete furanocoumarins into the culture medium; a major component, bergapten, and a minor one, xanthotoxin, were detected and identified by HPLC and GC/MS. Changes in phenylalanine ammonia-lyase (PAL) activity and furanocoumarin production after elicitor treatment were traced, showing that PAL activity increased rapidly, reached a maximum after 24 h, and then declined to the normal level after 96 h which preceded the induced bergapten production. The induced-PAL activity of the cultured cells established from an S-type plant which accumulated trace amounts of furanocoumarins was about 50% of that in the cultured cells from an N-type plant that accumulated more than 0.1% furanocoumarins in the underground parts. However, the elicited production of bergapten was about six times higher in the cell cultures from the S-type plant. Addition of the PAL inhibitor 2-aminoindan-2-phosphoric acid (AIP) at 10 microM suppressed the induction of PAL activity and furanocoumarin production.

Inhibitory activity of soyasaponin II on virus replication in vitro.

The antiviral activities of two saponins, soyasaponin I and II, isolated from soybean (Glycine max Merrill) were studied in vitro against herpes simplex virus type 1 (HSV-1). Soyasaponin II was more potent than soyasaponin I as shown by reduction of HSV-1 production. Soyasaponin II was also found to inhibit the replication of human cytomegalovirus, influenza virus, and human immunodeficiency virus type 1. The action was not due to inhibition of virus penetration and protein synthesis, but might involve a virucidal effect. When acyclovir and soyasaponin II were evaluated in combination for anti-HSV-1 activity, additive antiviral effects were observed for this virus.

Molecular cloning and functional expression of cDNAs for Glycyrrhiza glabra squalene synthase.

We have isolated two cDNAs (GgSQS1 and GgSQS2) encoding squalene synthase of Glycyrrhiza glabra L. by cross-hybridization with that of Arabidopsis thaliana squalene synthase under conditions of low stringency. Their nucleotide sequences contained an open reading frame for a polypeptide of 413 amino acids (GgSQS1) and 412 amino acids (GgSQS2), respectively. The deduced amino acid sequence of GgSQS1 exhibits 88%, 81%, 78%, 45-44%, and 45-41% identity to those of the GgSQS2, Nicotiana benthamiana. Arabidopsis thaliana, mammal, and yeast squalene synthases, respectively. To express the G. glabra enzymes in Escherichia coli, the entire coding region was subcloned into an expression vector. The cell-free extracts of E.coli transformed with the respective plasmid converted 3H-farnesyl diphosphate into squalene.

Genotypes and alkaloid contents of Datura metel varieties.

Datura metel L. var. muricata (BERNH.) DANERT was found to be double recessive with respect to the genes concerning the color and form of the corolla by breeding experiments involving four varieties, i.e. var. metel (white, simple corolla), var. rubra (purple, simple), var. fastuosa (purple, double or triple) and var. muricata (white, purple). The results support the proposal by Danert and others that these variants should be considered as varieties or forms of a single species, Datura metel. The analysis of tropane alkaloids in the seeds, flowers, and leaves of these four varieties showed that scopolamine was always dominant over hyoscyamine. The range of the scopolamine content (% of dry weight) of seeds, flowers, and leaves was 0.294 (var. rubra)-0.631 (var. fastuosa), 0.190 (var. metel)-0.698 (var. rubra), and 0.042 (var. rubra)-0.255 (var.metel), respectively. These findings proved that all the varieties, including var. muricata, which exhibited medium scopolamine content among the varieties, can be utilized as sources of scopolamine.

Restriction fragment length polymorphisms of rDNA and variation of essential oil composition in Atractylodes plants.

Total DNA was extracted from the leaves of Atractylodes lancea DE CANDOLLE, A. ovata DE CANDOLLE and A. japonica KOIDZUMI ex KITAMURA of various origins and hybridized with digoxigenin-labeled rice ribosomal DNA after digestion with eight different restriction endonucleases. The resulting restriction fragment length polymorphism (RFLP) profiles allowed us to distinguish the three Atractylodes species when DNA was digested with Sac I. Although atractylon was detected in the rhizomes of some of the cultivated strains of A. lancea, their RFLP profiles clearly indicate that these plants are not hybrids of A. ovata or A. japonica. RFLP analysis also revealed the presence of intraspecific variation in DNA sequence of rRNA locus among A. lancea as well as A. japonica.

Restriction fragment length polymorphisms of medicinal plants and crude drugs. II. Analysis of Glehnia littoralis of different geographical origin.

Total DNA was extracted from leaves of Glehnia littoralis belonging to various geographical strains with different furanocoumarin composition, and digested with restriction enzymes. Hybridization of digoxigenin-labeled probe containing rice ribosomal DNA to the digested DNA showed no difference in the restriction fragment length polymorphism (RFLP) profiles among the plants of different geographical origin. It is concluded that genetic diversity among the geographical strains of G. littoralis is so narrow as to be incapable of detecting RFLPs using rDNA as a probe.

Effects of sublingually administered nifedipine on left ventricular isovolumic relaxation, diastolic filling, and distensibility in patients with chronic coronary artery disease.

The acute effects of nifedipine (20 mg) on left ventricular diastolic function were investigated in 16 patients with chronic coronary artery disease by measuring left ventricular pressure with a manometer-tipped catheter and by measuring volume with cineangiography. Heart rates were maintained by right atrial pacing. Left ventricular peak systolic pressure (-15%; p less than 0.01 vs control) decreased significantly. With afterload reduction, left ventricular ejection fraction (+11%; p less than 0.01) increased. There was no significant change in left ventricular end-diastolic pressure. The diastolic peak filling rate of left ventricular volume significantly increased (+36%; p less than 0.05), whereas the time from end-systole to the peak filling rate remained unchanged. Administration of nifedipine did not improve left ventricular relaxation as assessed by the isovolumic pressure decay. There was also no significant change in the left ventricular diastolic pressure-volume relationship. We conclude that nifedipine improves left ventricular systolic function with afterload reduction but has little or no effect on left ventricular diastolic properties in patients with chronic coronary artery disease.

The production of antraquinones in callus cultures of Cassia tora.

Callus cultures were extablished from the seedlings of Cassia tora on a chemically defined medium supplemented with 2, 4-D and kinetin. A phytochemical investigation of callus tissues demonstrated the presence of chrysophanol, emodin, physcion, and an unidentified pigment, all of which are contained in the seeds of the original plant. The maximum content of antraquinones on a fresh weight basis was 0.334 percent, which is higher than the content of total anthraquinones in the dry seeds. Furthermore, it was shown that the production of these compounds is influenced by the concentrations of auxin and cytokinin supplied to the culture medium.