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PubMed1983

Dendrobine, an antagonist of beta-alanine, taurine and of presynaptic inhibition in the frog spinal cord.

1 The effects of dendrobine and nobiline, alkaloids isolated from Dendrobium nobile, on the electrical activity and on amino acid-induced depolarizations of primary afferent terminals were tested on the frog isolated spinal cord and were compared with those of picrotoxinin and strychnine. 2 Dendrobine (3 X 10(-5) M) caused a slight hyperpolarization in both dorsal and ventral roots and this hyperpolarization was accompanied by the augmentation of the dorsal root potential (DR-DRP) and the ventral root potential and reflex (DR-VRP and DR-VRR). The amplitude of the dorsal root reflex (DR-DRR) however, was reduced significantly. Nobiline (3 X 10(-5) M) had no significant effect on either the root potentials or the reflexes. 3 Dendrobine (3 X 10(-5) M) reduced the dorsal root potential induced by repetitive antidromic stimulation of ventral root (VR-DRP) as well as diminishing the maximum rate of rise of the dorsal root potential induced by the stimulation of adjacent dorsal roots (DR-DRP), during which time the amplitude of the DR-DRP was seen to be augmented. 4 Dendrobine (3 X 10(-5) M) reduced the beta-alanine- and taurine-induced depolarizations of primary afferent terminals, while having little effect upon GABA- and glycine-induced depolarizations. 5 Dendrobine (10(-5) M) reversibly blocked the presynaptic inhibition caused by antidromic conditioning stimulation of the ventral root. 6 These effects of dendrobine were qualitatively similar to those of strychnine but were somewhat different from those of picrotoxinin, a molecule having the same picrotoxane skeleton. 7 The present results are discussed with reference to the likely neurotransmitters involved in presynaptic inhibition in the frog spinal cord, and with respect to the structure-activity relationship of picrotoxane compounds as amino acid antagonists.

Action Potentials↗
PubMed2026

Assembly and comparative analysis of the mitochondrial genome of Pleione yunnanensis: genome structure and evolutionary insights.

BACKGROUND: Pleione yunnanensis a terrestrial or semi-epiphytic herbaceous plant belonging to the Orchidaceae family, is valued for both its medicinal uses and ornamental appeal. Although its chloroplast genomes have been sequenced, its complete mt genome had not previously been resolved, limiting genetic and evolutionary studies of the species. RESULTS: In this work, we assembled and characterized the first complete mt genome of P. yunnanensis, revealing a structurally complex, multibranched system composed of 14 circular-mapping molecules totaling 468,176 bp with a GC content of 44.32%. The genome encodes 44 annotated genes, including 28 protein-coding genes (PCGs), 15 tRNAs, and one rRNA. The multibranched architecture provides new evidence supporting the dynamic and recombinational nature of plant mt genomes. Repeat analysis uncovered 29 simple sequence repeats (SSRs), 19 tandem repeats, and 118 dispersed repeats, indicating a comparatively lower repeat abundance than that found in closely related orchids with similar mt genome sizes. Codon-usage profiling of PCGs showed a marked bias toward A/T-ending codons. Prediction of RNA editing sites identified 4,708 putative edits across mitochondrial PCGs. Most mitochondrial genes displayed Ka/Ks ratios close to 1.0, suggesting relaxed selective constraints or lineage-specific evolutionary patterns rather than strong positive selection. Moreover, we detected 69 chloroplast-derived homologous fragments, including 15 intact genes, suggesting ongoing plastid-mitochondrial DNA transfer. Phylogenetic reconstruction and collinearity comparisons demonstrated that P. yunnanensis clustered closely with Dendrobium species, including D. amplum and D. hancockii, within the Orchidaceae clade. CONCLUSIONS: This study provides the first complete mt genome of P. yunnanensis, providing a foundational genomic resource for the genus Pleione. The results not only improve our understanding of mt genome structure and evolution in Orchidaceae, but also offer valuable molecular evidence for phylogenetic inference, germplasm identification, and conservation of this endangered medicinal species.

Orchidaceae↗
PubMed2004

Antiosteoporotic activity of the water extract of Dioscorea spongiosa.

After 60 MeOH and water extracts of natural crude drugs were screened for their ability to stimulate osteoblast proliferation, four MeOH extracts (Cynomorium songaricum, Drynaria fortunei, Lycium chinense, Rehmannia glutinosa) and seven water extracts (Cornus officinalis, Dendrobium nobile, Dioscorea spongiosa, Drynaria fortunei, Eucommia ulmoides, Lycium chinensis, Viscum coloratum) showed that potent activities were evaluated for inhibition of osteoclast formation. The results indicated that the water extract of D. spongiosa not only showed the strongest stimulation of osteoblast proliferation but also possessed potent inhibitory activity aganist osteoclast formation, whereas it showed lower cytotoxicity in osteoblast and bone marrow cells. A further in vivo experiment determined the antiosteoporotic activity of this extract, in which it inhibited the decrease in cancellous bone mineral content, cancellous bone mineral density, and cortical bone mineral content of the proximal tibia in ovariectomized rats.

Animals↗
PubMedDate not supplied

[Microbiota of the Orchid rhizoplane].

Six bacterial strains isolated from the underground roots of the terrestrial orchid Calanthe vestita var. rubrooculata were found to belong to the genera Arthrobacter, Bacillus, Mycobacterium, and Pseudomonas. Strains isolated from the aerial roots of the epiphytic orchid Dendrobium moschatum were classified into the genera Bacillus, Curtobacterium, Flavobacterium, Nocardia, Pseudomonas, Rhodococcus, and Xanthomonas. The rhizoplane of the terrestrial orchid was also populated by cyanobacteria of the genera Nostoc and Oscillatoria, whereas that of the epiphytic orchid was populated by one genus, Nostoc. In orchids occupying different econiches the spectra of the bacterial genera revealed differed. The microbial complex of the terrestrial orchid rhizoplane differed from that of the surrounding soil.

Arthrobacter↗
PubMedDate not supplied

Erianin induces a JNK/SAPK-dependent metabolic inhibition in human umbilical vein endothelial cells.

BACKGROUND: Erianin is a natural product derived from Dendrobium chrysotoxum, with promising antitumor activity. MATERIALS AND METHODS: To evaluate the metabolic effect of erianin, a cytosensor assay for acidification rate, MTT assay, measurement of lactate, glucose and ATP were performed in human umbilical vein endothelial cells (HUVECs) exposed to 1-100 nM erianin. JNK/SAPK activity was detected by Western blot. RESULTS: Twelve- or 24- hour incubation with erianin induced a dose-dependent metabolic inhibition, as indicated by reduced acidification rate and cell viability, with an endothelium-selectivity. Erianin caused decreases in lactate production, glucose consumption and intracellular ATP level. Pretreatment with the JNK/SAPK inhibitor SP600125 significantly abolished these inhibitory responses, and especially restored the erianin-induced decreases in ATP and the erianin-induced phosphorylation of JNK/SAPK with dose- and time- dependence. CONCLUSION: Erianin inhibited endothelial metabolism in a JNK/SAPK-dependent manner. This mechanism may be involved in the potential antitumnor and antiangiogenic actions of erianin.

Adenosine Triphosphate↗
PubMed2005

[Studies on functional genes of Chinese herbal medicine].

In order to establish the foundation for modernization of Chinese herbal medicine, discovery of the functional genes related with the bioactive components of Chinese herbs and the rules of their expression was progressed for determining the regulatory mechanism, obtaining the core metabolic pathway and key regulatory factors of the medicinal components synthesis. In this article, the studies about plant's functional genes at home and abroad was introduced in three aspects: the pattern plants (rice, thaliana, etc.), the main technologic strategy (gene expression differentia, sequential tag of gene expression, DNA microarray technique and gene expression sequential analysis) and bio-informative method (comparative genomics). The current status of researches involving biosynthesis genes of flavonoids compounds and taxol, and the plant P450 genes were introduced. And the study of dendrobium functional genes conducted in authors' lab was also reviewed.

Drugs, Chinese Herbal↗
PubMedDate not supplied

[Auxin production by bacteria associated with orchid roots].

Bacteria associated with the roots of greenhouse tropical orchids were shown to produce indole-3-acetic acid (IAA) and to excrete it into the culture liquid. The presence and activity of IAA were demonstrated colorimetrically, by thin-layer chromatography, and by biotests. The associated bacteria varied in their ability to excrete indole compounds (1-28 microg/ml nutrient broth). Addition of tryptophan to the growth medium enhanced phytohormone production. Upon addition of 200 microg/ml tryptophan, the bacteria isolated from Dendrobium moschatum roots (Sphingomonas sp. 18, Microbacterium sp. 23, Mycobacterium sp. 1, Bacillus sp. 3, and Rhizobium sp. 5) produced 50.2, 53.1, 92.9, 37.6, and 60.4 microg IAA/ml respectively, while the bacteria isolated from Acampe papillosa roots (Sphingomonas sp. 42, Rhodococcus sp. 37, Cellulomonas sp. 23, Pseudomonas sp. 24, and Micrococcus luteus) produced 69.4, 49.6, 53.9, 31.0, and 39.2 microg IAA/ml. Auxin production depended on cultivation conditions and on the growth phase of the bacterial cultures. Treatment of kidney bean cuttings with bacterial culture liquid promoted formation of a "root brush" with location height 7.4- to 13.4-fold greater than the one in the control samples. The ability of IAA-producing associated bacteria to act as stimulants of the host plant root development is discussed.

Bacteria↗
PubMed2003

[Effects of extracts of Chinese medicines on Ganoderma lucidum in submerged culture].

Effects of water and ethanol extracts of 10 Chinese medicines, such as Astragalus membranaceus, Coix lachryma-jobi, etc., on biomass and exopolysaccharide of Ganoderma lucidum were studied by submerged culture. The results showed: water extracts of all medicines can improve the culture of G. lucidum except of A. membranaceus, ethanol extracts of C. lachryma-jobi, Dioscorea opposita, Codonopsis pilosula, and Achyranthes bidentata( < 187.5g Medicine/L substrate) can also increase the biomass of G. lucidum, but the ethanol extracts of Angelica sinensis, Dendrobium nobile check the growth of G. lucidum. The production of exopolysa-ccharide can be improved by all the Chinese medicines and their dosage used in this experiment, Although A. sinensis, D. Nobile check the growth of G. lucidum, they could stimulate the secretion of exopolysaccharide in lower dosage. It is concluded that some Chinese medicines, such as C. lachryma-jobi, D. opposita, C. pilosula, etc. can be processed by the fermentation of G. lucidum, and bio-active compound can be produced by adding appropriate Chinese medicine in the substrate to culture G. lucidum.

Biomass↗
PubMed1990

A study on mass culture of Panax quinquefolium cells.

By omitting the component NH4NO3 and doubling the amount of KNO3 in MS medium, the Panax quinque folium cells cultured in such medium grew more rapidly and their saponin content was much higher than that cultured in regular MS medium. The growth rate and saponin content of the cells cultured in such medium (KNO33300 mg/l) increased 65.1% and 166.2% respectively as compared with that cultured in the regular medium. The application of oligosaccharins from Panax ginseng and Dendrobium candidum also increased their saponin content and growth rate. Especially, the content of Rg group saponins was apparently raised. It took more than 25 days for the cell suspension cultures to produce saponins in large amounts. The curve of saponin formation lagged slightly behind the growth curve in cell suspension culture and fermentation culture. The cell fermentation culture with a stabilized pH value was better than the culture with the pH value changing spontaneously on saponin content, growth rate and biomass. Finally, the culture patterns of P. quinque folium cells were compared and discussed.

Cells, Cultured↗
PubMed2004

Enantioselective synthesis of (-)-dendroprimine and isomers.

An enantioselective and diastereoselective synthesis of six 5,7-dimethylindolizidine isomers is described via an intramolecular cyclization that involves an allylsilyl nucleophilic group and an acyliminium ion. The first total synthesis of naturally occurring (-)-dendroprimine has been achieved in five steps.

Alkaloids↗
PubMed2006

Transgenic expression of DwMYB2 impairs iron transport from root to shoot in Arabidopsis thaliana.

In plant, iron uptake and homeostasis are tightly regulated to ensure its absorption from soil and to avoid excess iron in the cell. Many genes involved in this process have been identified during past several years, but there are many problems remain unsolved in the genetic regulation of whole plant iron trafficking and allocation. MYB transcription factors contain tandem repeats of a approximately 50 amino acid DNA-binding motif (R) and are involved in the regulation of many aspects of plant development, hormone signaling and metabolism. Here, we report that the ectopic expression of orchid R2R3-MYB gene DwMYB2 in Arabidopsis thaliana confers the transgenic plants hypersensitivity to iron deficiency. In DwMYB2 transgenic plants, the iron content in root is two-fold higher compared to that in wild-type root, while the reverse is true in shoot. This imbalance of iron content in root and shoot suggested that the translocation of iron from root to shoot was affected by the expression of DwMYB2 in the transgenic plants. Consistently, gene chip and reverse transcription-polymerase chain reaction analysis revealed that the ferric-chelate reductase gene, AtFRO2, and the iron transporter gene, AtIRT1 and AtIRT2, are up-regulated by DwMYB2 expression, while other potential iron transporters such as AtIREG1, AtFRD3 and NRAMP1 are down-regulated. In addition, the expression of several putative peptide transporters and transcription factors are also altered in the 35S::DwMYB2 transgenic lines. These data provide us insight into the whole plant translocation of iron and identify candidate genes for iron homeostasis in plants despite the fact that a heterologous gene was expressed.

Amino Acid Sequence↗
PubMed2001

Erianin induces apoptosis in human leukemia HL-60 cells.

AIM: To investigate the effect of erianin on human HL-60 cell line and explore its mechanism of apoptosis in vitro. METHODS: Inhibition of proliferation was measured with colorimetric MTT assay. The morphologic changes were observed by fluorescence and electron microscopes. DNA fragmentation was visualized by agarose gel electrophoresis, and the DNA degradation was determined by flow cytometry. Immunohistochemical analysis was used to identify the expression of bcl-2 and bax genes. RESULTS: The growth of human HL-60 cells was significantly inhibited by erianin 20-81.9 nmol/L during 72 h treatment (P < 0.01). The IC50 value was 38 nmol/L after a 24-h exposure to erianin, while that of vincristine, the positive control, was 101 nmol/L. The typical morphologic changes were observed and the nuclear DNA fragmentation exhibited "ladder" pattern. The cell cycle of HL-60 cells was arrested in G2/M phase, and expression of bcl-2 gene was decreased while that of bax was increased. CONCLUSION: Erianin showed potent inhibitory activity on the proliferation of HL-60 cells. The inhibition might be relative to the apoptosis induced by erianin and the altered expression of bcl-2 and bax genes in HL-60 cells.

Antineoplastic Agents, Phytogenic↗
PubMed2002

[Studies on second metabolites of an endophytic fungus (II)].

OBJECTIVE: To study the chemical constituents from the cultured mycelia of a fungus Cephalosporium which accelerate the growth of plant. METHOD: The constituents were isolated by column chromatography and identified by advanced physical and spectral analysis. RESULT: Eleven compounds including 3-isopropyl-6-(1-methylpropyl) piperazine-2,5-dione(I), choline sulfate(II), 2-[(2-hydroxy tetracosanoyl) amino]-1,3,4-octadecatriol(III) were isolated and identified. CONCLUSION: Compound I, II were isolated from Cephalosporium genus for the first time.

Acremonium↗