Biomedical subjects

Ying-Jin Yuan

Publications and source records attributed to Ying-Jin Yuan.

At least 19 recordsLinked to original sources

PubMed2006

Proteomic analysis reveals the spatial heterogeneity of immobilized Taxus cuspidata cells in support matrices.

A proteomic approach was used to study the responses of Taxus cuspidata cells to local microenvironments in different zones of immobilized support matrices. Analysis of protein spots by 2-DE revealed significant differences in the abundance of 31 spots, 28 spots, and 23 spots in outer, middle, and central zone cells between the immobilized and suspended cells. Six of these proteins, identified by MALDI-TOF-MS, were involved in the regulation of carbohydrate, nitrogen, and sulfur metabolisms. Immobilization triggered an increase in taxol production of the immobilized cells in the middle and central zones compared to that of the suspended cells. A negative relation between taxol production and the mitotic index was observed in the cells in the immobilization support matrix. Cells in the outer zone had high mitotic index and low taxol production, while cells in the middle and central zones showed low mitotic index and high taxol production. The abundance of S-adenosylmethionine synthetase, which was identified as one of the differentially expressed proteins, was positively correlated to the cell division activity in the immobilized cell cultures.

Amino Acid Sequence↗

PubMed2006

Spatio-temporal distributions of metal ions and Taxol of Taxus cuspidata cells immobilized on polyurethane foam.

Distinct spatio-temporal variations of metal ions and Taxol production were observed for Taxus cuspidata cells immobilized on polyurethane foam. The Taxol content in the inner foam layer reached 215 microg g(-1) at day 30, which was 40-fold higher than that in the outer foam layer, and the Ca2+ and Mg2+ contents were 5.3 and 3.7 times higher, while the K+ content was 5.5 times lower. Thus higher intracellular Ca2+ and Mg2+ contents and lower intracellular K+ content may favor the Taxol biosynthesis in immobilized Taxus cuspidata.

Antineoplastic Agents, Phytogenic↗

PubMed2006

Comparison of JNK (c-Jun N-terminal kinase)-like MAPK (mitogen-activated protein kinase) phosphorylation between immobilized cultures and Couette-type shear reactor cultures of Taxus cuspidata (Japanese yew) cells.

The signal mechanism of Taxus cuspidata (Japanese yew) cells involved in response to shear stress and immobilized matrices was investigated. Western-blot analysis showed that the immobilized cultures altered the degree of phosphorylation of the JNK (c-Jun N-terminal kinase)-like and a 41 kDa p38-like MAPKs (mitogen-activated protein kinases), particularly the 52 and 45 kDa JNK-like MAPKs. The increased rotation speeds up-regulated the degree of phosphorylation of 45 and 47 kDa JNK-like MAPKs, whereas the 41 kDa p38-like MAPK was not significantly changed. The level of phosphorylation of JNK-like MAPKs in the outer zone cells of immobilized matrices was the highest among the different zone cells, which was identical with that of T. cuspidata cells exposed to hydrodynamic shear stresses. The highly specific p38- or JNK-MAPK inhibitors strongly reduced respectively the p38- or JNK-like MAPK phosphorylation, which also demonstrated that there were no cross-reactions between the p38-like MAPK and JNK-like MAPK in T. cuspidata cells. By a comparison of the effects of the immobilization and laminar shear stress on the phosphorylation of p38- and JNK-like MAPKs in T. cuspidata cells, these findings suggested that the JNK-like MAPK signal pathways may be involved in T. cuspidata cell response to the hydrodynamic shear stress, rather than to the p38-like MAPK.

Bioreactors↗

PubMed2006

Differential analysis of secondary metabolites by LC-MS following strain improvement of Streptomyces lydicus AS 4.2501.

Metabolite variations in a high-yielding mutant and its parent strain were studied by comparative LC-MS analysis after strain improvement. Streptomyces lydicus AS 4.2501-P28, a propionate-resistant mutant isolated by the high-frequency screening method using the principle of eliminating precursor inhibition effects, showed an increase of 267% in streptolydigin titre over the starting strain. Culture extracts of this mutant and its parent strain were analysed in parallel by an LC-MS technique, including full scan and extracted-ion scan, ESI-MS (electrospray-ionization MS) detection, DAD (diode-array detection) and MS2 (tandem MS) measurement. The main metabolic variations were obviously found in intermediates, metabolites and biosynthetic pathways: two unknown metabolites with the molecular [M-H]- ions at m/z 423.3 and 687.2, corresponding to two branch pathways, were blocked in the mutant, and the accumulation of a significant intermediate at m/z 363.1 [M-H]- decreased dramatically in the mutant cultures, resulting in the overproduction of streptolydigin (an antibiotic that inhibits prokaryotic RNA polymerase) in the mutant. Ion fragmentations of the tandem-MS spectra provided experimental evidence for the structural characterization of the three compounds obtained. In comparison with the traditional methods, comparative LC-MS analysis was rapid, sensitive and suitable for characterizing intermediates, metabolites and pathways for elucidation of the metabolic alterations after the isolation of improved strains.

Aminoglycosides↗

PubMed2006

Functional analysis of type II thioesterase of Streptomyces lydicus AS 4.2501.

Constructing a mutant strain of single gene disruption is the basis for the study of gene function and metabolomics. Systematic and complete genome sequencing is the basis of genetic manipulation. In the case of a little knowledge about the Streptomyces lydicus genome and the speculation that polyketide synthases (type I) might be responsible for the polyketide side chain biosynthesis of streptolydigin, a 588-bp fragment was amplified by polymerase chain reaction (PCR) according to the homology existing in the same functional genes among Streptomyces. A mutant strain of this gene was constructed by single crossover homologous recombination. The results of sequence analysis as well as the metabolite analysis of the mutant and the original strain by liquid chromatography/mass spectroscopy indicated that this fragment was part of type II thioesterase (TE) gene, which was required for streptolydigin biosynthesis like other type II TEs function in related antibiotics biosynthesis. Furthermore, targeted gene manipulation based on PCR was a powerful tool for studying gene function and metabolomics, especially when little was known about the genomic sequence of streptomyces.

Amino Acid Sequence↗

PubMed2006

[Application of new method for data processing in metabonomic studies].

AIM: To search for and application of new method for data processing in metabonomic studies. METHODS: The paper proposed that in the processing of metabonomic data, robust PCA method can be used to diagnose outliers; and unstable variables judged by comparison between difference within class and difference among classes should be excluded before data analysis; moreover, the data should be properly scaled before further processing. The proposed methods were used to preprocess metabolomic data of four genotypes of the Arabidopsis thaliana plants. RESULTS AND CONCLUSION: The outcome demonstrated that the application of these methods can obviously improve clustering and biomarker identifying results.

Algorithms↗

PubMed2005

Nitric oxide mediates inactivation of glutathione S-transferase in suspension culture of Taxus cuspidata during shear stress.

The importance of nitric oxide (NO) in regulating plant cell responses to environmental stresses is becoming evident. Here the possible role of NO in suspension cultures of Taxus cuspidata under shear stress was investigated in a Couette-type shear reactor. It was found that shear stress with 190 s(-1) caused NO generation in 8 h. NO formation can be inhibited by N-nitro-L-arginine, a nitric oxide synthase inhibitor. Moreover, the activity of glutathione S-transferase (GST), a principal enzyme responsible for detoxification, decreased during shear stress. This inactivation partially recovered when NOS inhibitor or NO scavenger was added into cell cultures during shear stress. Treatment with reactive nitrogen species (RNS) also caused inactivation of GST in cells. The results indicate that NO plays a crucial role in GST inactivation in Taxus cuspidata cells under shear stress.

Cells, Cultured↗

PubMed2005

Ce(4+) induced down-regulation of ERK-like MAPK and activation of nucleases during the apoptosis of cultured Taxus cuspidata cells.

Ce(4+) (Ce(NH(4))(2)(NO(3))(6)) at 1mM induces apoptosis of suspension cultures of Taxus cuspidata cells; however, the underlying signal mechanisms are unknown. We show here that a 46-kDa ERK (extracellular signal-regulated kinase)-like MAPK appears to be down-regulated at 4h, and remains at low levels for up to 48 h. An inhibitor of superoxide anions (O(2)(-)) generation, diphenyl iodonium (DPI) successfully blocks down-regulation of ERK-like MAPK and degradation of DNA. Moreover, a 41-kDa p38-like MAPK activity remains unchanged from 0.5 to 48 h. The p38 inhibitor SB202190 effectively inhibits p38-like MAPK activity, however, SB202190 fails to modify the apoptotic rate at concentrations up to 100 microM. Three nuclease (34-kDa, 22-kDa and 20-kDa) activities are profoundly enhanced in Ce(4+)-induced T. cuspidata cells. They have an optimum pH at 6.8, and are stimulated by Ca(2+)/Mg(2+). Caspase-3 inhibitor, Ac-DEVD-CHO, does not attenuate the 34-kDa nuclease activity, but inhibits the 22-kDa and the 20-kDa nuclease activities. In addition, inhibition of O(2)(-) generation by DPI significantly reduces the three nuclease activities. In conclusion, the present study suggests that down-regulation of ERK-like MAPK, burst of O(2)(-), activation of caspase-3-like and induction of three nucleases as the key signaling events mediating apoptosis in Ce(4+)-induced cultured T. cuspidata cells.

Apoptosis↗

PubMed2005

Inhibition of rat vascular smooth muscle cell proliferation by extract of Ligusticum chuanxiong and Angelica sinensis.

Ligusticum chuanxiong (LC) and Angelica sinensis (AS) have been widely used as traditional Chinese medicine to treat some pathological settings such as atherosclerosis and hypertension. The aim of this paper is to determine the effects of the extract of LC and AS (ELCAS) on serum-induced vascular smooth muscle cell (VSMC) proliferation, cell cycle and nitric oxide production. The results show that ELCAS significantly inhibited proliferation and protein synthesis of VSMC in a dose and time dependent manner. The cell population assessed by flow cytometry in the G(0)/G(1) phase increased 74% versus 79.8%, concomitant with a decrease in the S phase, 7.4% versus 4.2%, for control versus ELCAS (300 microg/ml). On the other hand, ELCAS significantly increased nitric oxide production of VSMC. The data suggest that ELCAS markedly inhibited VSMC proliferation by arresting G(1) to S progression, which may be associated with nitric oxide production.

Angelica sinensis↗

PubMed2005

A fluorescence study of sodium hyaluronate/surfactant interactions in aqueous media.

The interactions between sodium hyaluronate, an anionic polysaccharide, with surfactants (anionic and nonionic) were investigated using pyrene fluorescence measurement methods. The change of micropolarity produced by the interaction was monitored by the measurement of emission intensity ratio between the first and third bands (I1/I3), and the intensity ratio of the excimer and the third vibration monomer band (I(E)/I(M)). Because the hydrophilic heads on the SDS were attracted by the domains formed by the hydroxyl groups of hyaluronate, the I1/I3 ratio was reduced by the addition of hyaluronate at lower than 0.06% of sodium dodecyl sulfate (SDS) concentration. No aggregation was observed between hyaluronate and nonionic surfactants (Tween-80 and Cremophor EL) in the whole concentration range studied. At a higher concentration of surfactant, the I1/I3 ratio of hyaluronate/surfactant was influenced by the addition of saccharide (glucose, lactose, or mannitol). However, the effect of saccharide could be reduced by the addition of salt.

Buffers↗

PubMed2005

A modified PCR system for amplifying beta-ketoacyl-ACP synthase gene fragments with DNA from Streptomyces luteogriseus.

Streptomyces luteogriseus strain 099, producing a new type of macrolide antibiotic with anti-coxB6 virus and anti-HIV protease activities, was isolated from soil. PCR was optimized to amplify beta-ketoacyl-ACP synthase (KS) genes. The system was optimized around the use of higher concentrations of DMSO (15% vs. 10% v/v) and dNTP (500 microM vs. 50-200 microM) and a lower annealing temperature (55 degrees C vs. 60-70 degrees C) than the normal PCR method used to amplify high GC content DNA.

3-Oxoacyl-(Acyl-Carrier-Protein) Synthase↗

PubMed2005

Signal role for activation of caspase-3-like protease and burst of superoxide anions during Ce4+-induced apoptosis of cultured Taxus cuspidata cells.

The signal events of 1 mM Ce4+ (Ce(NH4)2(NO3)6)-induced apoptosis of cultured Taxus cuspidata cells were investigated. The percentage of apoptotic cells increased from 0.82% to 51.32% within 6 days. Caspase-3-like protease activity became notable during the second day of Ce4+-treatment, and the maximum activity was 5-fold higher than that of control cells at the fourth day. When the experiment system was pretreated with acetyl-Asp-Glu-Val-Asp-aldehyde (Ac-DEVD-CHO) at 100 microM, caspase-3-like activity resulted in distinct inhibition by 70% and 77.3% after 3 and 4 days of induction. Furthermore, 100 microM Ac-DEVD-CHO partially reduced the apoptotic cells by 58.6% and 60.8% at day 4 and 5 respectively. Ce4+ induced superoxide anions (O2*-) transient burst, and the first peak appeared at around 3.7-4 h, the second appeared at about 7 h. Both O2*- burst and cell apoptosis were effectively suppressed by application of diphenyl iodonium (NADPH oxidase inhibitor). Inhibition of O2*- production attenuated caspase-3-like activation by 49% and 53.6% during day 3 and 4 respectively. In addition, a total of 15 protein spots changed in response to caspase-3-like protease activation were identified by two-dimensional gel electrophoresis. These results suggest that Ce4+ of 1 mM induces apoptosis in suspension cultures of T. cuspidata through O2*- burst as well as caspase-3-like protease activation. The burst of O2*- exerts its activity as an upstream of caspase-3-like activation. Our results also implicate that other signal pathways independent of an O2*- burst possibly participate in mediating caspase-3-like protease activation.

Apoptosis↗

PubMed2005

Aqueous extract of Salvia miltiorrhiza attenuates increased endothelial permeability induced by tumor necrosis factor-alpha.

Salvia miltiorrhiza Bunge, a traditional Chinese herbal medicine, is often used for prevention and treatment of cardiovascular disorders such as atherosclerosis. To understand its mechanism of pharmacological action, its effects on endothelial monolayer permeability are studied. The present study demonstrated that extract of S. miltiorrhiza (ESM) and its major ingredients, Danshensu (DSS) and salvianolic acid B (Sal B), inhibited tumor necrosis factor (TNF-alpha) induced endothelial permeability, whereas the other major ingredient, protocatechualdehyde, was ineffective. ESM, DSS and Sal B also repressed expression of vascular endothelial growth factor (VEGF) and extracellular signal-regulated kinase (ERK) activation in TNF-alpha induced HUVEC cells. Furthermore, it was found that ESM attenuated the disorganization of vascular endothelial (VE)-cadherin induced by TNF-alpha. The effect of ESM on TNF-alpha induced endothelial permeability and redistribution of VE-cadherin is likely due to a reduction of VEGF protein expression as a result of modulation of the ERK signaling pathway. Endothelial cell hyperpermeability is implicated in inflammation and subsequent ischemic reperfusion injury and atherosclerosis. Data from this study suggest that one of the mechanisms S. miltiorrhiza exerts its pharmacological effect is through its modulation of endothelial cell permeability.

Benzaldehydes↗

PubMed2005

Aqueous extract of Salvia miltiorrhoza regulates adhesion molecule expression of tumor necrosis factor alpha-induced endothelial cells by blocking activation of nuclear factor kappaB.

Salvia miltiorrhoza Bunge is a traditional herb medicine often used in China for the treatment of cardiovascular disorders, such as atherosclerosis. The purpose of this study was to examine the effect of aqueous extract of Salvia miltiorrhoza Bunge (ESM) on expression of adhesion molecules in tumor necrosis factor (TNF)alpha-induced endothelial cells. When preincubated with ESM (100, 200, 400 microg/mL) for 18 hours, the adhesion of HL-60 cells to TNFalpha-induced endothelial cells was significantly decreased in a concentration-dependent manner, and down-regulation of adhesion molecules, intracellular cell adhesion molecule-1 (ICAM-1), vascular cell adhesion molecule-1 (VCAM-1), was also observed. The inhibitory effect of ESM on TNFalpha-induced VCAM-1 expression was attenuated by inhibition of intracellular glutathione (GSH) synthesis. In addition, ESM also significantly inhibited TNFalpha-induced translocation of nuclear factor kappaB (NF-kappaB) from cytoplasm to nuclei in endothelial cells. These results demonstrated that inhibition of ESM on the expression of adhesion molecules may result from its blocking activation on NF-kappaB. It may imply one of the mechanisms by which ESM exerts its beneficial effect preventing the progress of atherosclerosis.

Cell Adhesion Molecules↗

PubMed2005

Antioxidant responses to oleic acid in two-liquid-phase suspension cultures of Taxus cuspidata.

Two-liquid-phase plant cell cultures employ the use of a partitioning system to redirect extracellular product into a second phase. After the addition of organic solvent, in order to understand the defense system of Taxus cuspidata cells to organic solvent in two-liquid-phase suspension cultures, we investigated cells' antioxidant metabolism. The results showed that T. cuspidata cells responded to oleic acid with oxidative bursts in both intracellular H2O2 and extracellular O2-* production. Inhibition studies with diphenylene iodonium suggested that the key enzyme responsible for oxidative bursts was primarily NADPH oxidase. Investigation of the relationship between reactive oxygen species (ROS) and defense responses induced by oleic acid indicated that 4% (v/v) oleic acid increased the levels of antioxidant enzymes of superoxide dismutase, ascorbate peroxidase, and catalase and the antioxidant capacity of reduced ascorbate and glutathione. However, when oleic acid content reached a critical value (6% [v/v]), no further increase in antioxidant enzymes and antioxidant capacity was observed, indicating that the defense responses played a role in a certain range of oleic acid content, beyond which the overall ROS scavenging machinery was not induced and the peroxidation of membrane lipids emerged.

Antioxidants↗

PubMed2005

Reactive oxygen species, cell growth, and taxol production of Taxus cuspidata cells immobilized on polyurethane foam.

Dynamic changes in reactive oxygen species (ROS) of Taxus cuspidata cells immobilized on polyurethane foam were investigated and the relation between ROS content and taxol production was discussed. Immobilization shortened the lag period of cell growth and moderately increased H2O2 and O2-* contents inside the microenvironment within the first 15 d. After 20 d, excessive production of H2O2 and O2-* was observed accompanied by marked increases in membrane lipid peroxidation and cell membrane permeability. The taxol content of immobilized cells was fourfold that of suspended cells at d 35. The addition of exogenous H2O2 barely affected malondialdehyde content and cell membrane permeability but led to an obvious accumulation of taxol. It is inferred that the intracellular and extracellular H2O2 inside the microenvironment might be one factor promoting taxol biosynthesis under the immobilization stress.

Cell Culture Techniques↗

PubMed2005

[Progress in detection methods of single nucleotide polymorphisms].

Single nucleotide polymorphism (SNP) is the third generation genetic marker. SNP detection now is becoming increasingly important means in molecular diagnostics, clinical assay and novel drug development. It plays an essential role in drug resistance and anaphylactic reaction and has the importance in theoretical studies of gene location, hereditary diseases and human origin. With the accomplishment of human genome sequencing, the genotyping and discovering of SNP are becoming hot subjects in genetics and biomedicine researches. The methods for SNP detection were renewed rapidly and developed fast in past few years. In this review, several newly established detection methods including gene chip, molecular probe, fluorescence polarization and resonance, mass spectrometry, and bacterial magnetic particle are discussed. It could be expected that an accurate and sensitive, simple and easy-to-handle SNP technology with low cost and high throughput will be available on the basis of research breakthroughs of biochemistry, engineering and analytic software.

Fluorescence Polarization↗

PubMed2004

Inclusion complexes of paclitaxel and oligo(ethylenediamino) bridged bis(beta-cyclodextrin)s: solubilization and antitumor activity.

The inclusion complexation behavior of paclitaxel with a series of oligo(ethylenediamino) bridged bis(beta-cyclodextrin)s possessing bridge chains in different length (1-4) has been investigated in order to improve the water solubility of paclitaxel. It is found that only the long-tethered bis(beta-cyclodextrin)s 1 and 2 can form the inclusion complexes with paclitaxel, which are characterized by NMR, SEM, XRD, FT-IR, TG-DTA, DSC, and microcalorimetry technology. The results obtained show that bis(beta-cyclodextrin)s 1 and 2 are able to solubilize paclitaxel to high levels up to 2 and 0.9 mg/mL, respectively. The high complex stability of bis(beta-cyclodextrin) 1 and paclitaxel is discussed from thermodynamic viewpoint. Furthermore, the cytotoxicity of these complexes assessed using a human erythroleukemia K562 cell line indicates that the IC(50) value of 1/paclitaxel complex is 6.0 x 10(-10) mol/dm(3) (calculated as paclitaxel molar concentration), which means that the antitumor activity of 1/paclitaxel complex is better than that of parent paclitaxel (IC(50) value 9.8 x 10(-10) mol/dm(3)). This high antitumor activity, along with the satisfactory water solubility and high thermal stability of the 1/paclitaxel complex, will be potentially useful for its clinical application as a highly effective antitumor drug.

Antineoplastic Agents↗