Biomedical subjects

Qing Zhao

Publications and source records attributed to Qing Zhao.

At least 37 records · Page 2Linked to original sources

PubMed2006

[Analysis of Toll-like receptor 4 and myeloid differentiation protein-2 interaction with fluorescence resonance energy transfer].

OBJECTIVE: To study the interaction between Toll-like receptor (TLR) 4 and myeloid differentiation protein-2 (MD-2) in living cells using fluorescence resonance energy transfer (FRET) technology. METHODS: The coding sequences of TLR4 and MD-2 (without the signal peptide sequence) were amplified by PCR and cloned into enhanced cyan fluorescence protein (CFP) and enhanced yellow fluorescence protein (YFP) expression vectors carrying TLR4 signal peptides (pECFP-C1-SP and pEYFP-C1-SP). HEK293 cells were transfected respectively or together with the reconstructed plasmids verified by enzyme digestion and sequence analysis, and the expression and sublocalization of these fluorescence proteins in the cells were observed using fluorescence microscope. FRET in the cells coexpressing CFP-TLR4 and YFP-MD-2 was detected using routine and acceptor photobleaching method. RESULTS: The reconstructed plasmids were expressed in HEK293 cells. The cyan or yellow fluorescence was located in the cytoplasm, mainly around the nucleus in the cells transfected with pECFP/TLR4 or pEYFP/MD-2, and both the cyan and yellow fluorescence located mainly in the membrane and occasional in the cytoplasm of cells cotransfected with pECFP/TLR4 and pEYFP/MD-2. Routine or acceptor photobleaching detected FRET phenomena in cells coexpressing CFP-TLR4 and YFP-MD-2, suggesting direct interaction between TLR4 and MD-2. CONCLUSION: This study provides direct evidence of the interaction between TLR4 and MD-2 in living cells.

Cell Line↗

PubMed2005

Fabrication of polydiacetylene nanowires by associated self-polymerization and self-assembly processes for efficient field emission properties.

The paper described here concerns a challenge of general interest for producing a novel structure of a polymer aggregate, the achievement of nanowires with controlled diameters. We provide a strategy for fabricating a supramolecular polymer, in which ordered polydiacetylene nanowires can be obtained by associated self-polymerization and self-assembly processes. The polymer nanowire film shows excellent field emission properties with the turn-on field of 8.2 V/mum at 10 muA/cm2 and the maximum current density of 5 mA/cm2 at an applied field of 15 V/mum.

Acetylene↗

PubMed2005

Cytochrome c acts as a cardiolipin oxygenase required for release of proapoptotic factors.

Programmed death (apoptosis) is turned on in damaged or unwanted cells to secure their clean and safe self-elimination. The initial apoptotic events are coordinated in mitochondria, whereby several proapoptotic factors, including cytochrome c, are released into the cytosol to trigger caspase cascades. The release mechanisms include interactions of B-cell/lymphoma 2 family proteins with a mitochondria-specific phospholipid, cardiolipin, to cause permeabilization of the outer mitochondrial membrane. Using oxidative lipidomics, we showed that cardiolipin is the only phospholipid in mitochondria that undergoes early oxidation during apoptosis. The oxidation is catalyzed by a cardiolipin-specific peroxidase activity of cardiolipin-bound cytochrome c. In a previously undescribed step in apoptosis, we showed that oxidized cardiolipin is required for the release of proapoptotic factors. These results provide insight into the role of reactive oxygen species in triggering the cell-death pathway and describe an early role for cytochrome c before caspase activation.

Animals↗

PubMed2005

2-Arachidonoylglycerol stimulates activator protein-1-dependent transcriptional activity and enhances epidermal growth factor-induced cell transformation in JB6 P+ cells.

2-Arachidonoylglycerol (2-AG) is the most abundant endocannabinoid, and it plays a critical role in cannabinoid receptor-mediated cell signaling. Although 2-AG was shown to induce ERK activation via the cannabinoid receptor 1 (CB1), only a nonspecific CB receptor agonist and antagonist was used in those studies. Whether cannabinoid receptor 2 (CB2) is involved in 2-AG-induced ERK activation is still unclear. Moreover, whether 2-AG is involved in mediation of AP-1 activity and cell transformation is also not known. In the present study, we show that 2-AG stimulates AP-1-dependent transcriptional activity and enhances epidermal growth factor-induced cell transformation in mouse epidermal JB6 P+ Cl41 cells. Using JB6 P+ C141 cells, stably transfected with an AP-1 luciferase reporter, we found that 10 microm 2-AG induced up to a 3-fold stimulation of AP-1 transcriptional activity. The AP-1 stimulation appeared to be mediated by ERK but not JNK or p38 kinase. PD98059, a specific inhibitor of MEK1, almost completely blocked 2-AG-induced ERK phosphorylation and AP-1 activation. Using CB1/2-/- murine embryonic fibroblasts, we present the first direct evidence that both cannabinoid receptors 1 and 2 (CB1/2) are involved in 2-AG-induced ERK activation. 2-AG could not stimulate ERK phosphorylation or Fyn kinase activity in dominant negative Fyn. In addition, the Fyn inhibitor PP2 blocked 2-AG-induced Fyn kinase activity and ERK phosphorylation and activity. Small interfering RNA Fyn also suppressed 2-AG-induced ERK phosphorylation. Interestingly, 2-AG enhanced epidermal growth factor-induced AP-1 DNA binding and cell transformation. Taken together, our data provide direct evidence suggesting that 2-AG may have a novel role in cell transformation and carcinogenesis in a signaling pathway involving CB1/2 and activation of Fyn, ERKs, and AP-1.

Animals↗

PubMed2005

Determination of polyaromatic hydrocarbons in river water using a sorbent consisting of removable octadecyltrimethylammonium ions attached to cation exchange silica in conjunction with commercial C18 silica.

An application that highlights the usefulness of a solid phase extraction sorbent having a removable surfactant "stationary phase" is introduced. Polyaromatic hydrocarbons (PAHs) efficiently trap on commercially available non-polar sorbents (i.e., C(18) silica). However, solvents that are necessary to break strong hydrophobic interactions between the analyte and sorbent are harmful and incompatible for direct introduction into a reversed phase liquid chromatographic setup. In the presented approach, the entire "stationary phase"-analyte association is removed, resulting in very efficient elutions with a final extract that is mild and reversed phase liquid chromatographic compatible. Commercial C(18) silica was placed adjacent to this sorbent to provide more efficient trapping of less hydrophobic PAHs. PAHs were preconcentrated from river water and were determined using fluorescence detection coupled to HPLC. Detection limits for all PAHs examined were in the sub [micro sign]g L(-1) level.

Cation Exchange Resins↗

PubMed2005

Patterned growth of ZnO nanorod arrays on a large-area stainless steel grid.

Large-area ZnO nanorod arrays have been synthesized successfully on a stainless steel grid at a mild growth temperature of around 400 degrees C. The as-grown ZnO nanorods have uniform diameters of about 30-50 nm with approximately 5 nm tips. Patterned growth can be realized by engineering the shape of the grid in the growth. Photoluminescence demonstrates a sharp strong UV peak and a broad green band. The growth method provides a promising way of producing nanorod arrays with good controllability in patterns and morphologies, which will be critical in potential application such as high-efficiency filtering and catalysts.

Journal Article↗

PubMed2005

Field emission properties of large-area nanowires of organic charge-transfer complexes.

In this contribution, large-area organic charge-transfer complex (AgTCNQ and CuTCNQ) nanowires were synthesized by organic vapor-solid-phase reaction at mild experimental conditions. These nanowires were facilitated on the surface of Cu and Ag foils or different kinds of substrates coated with a layer of silver and copper on a large scale. The excellent field emission properties were observed in the as-grown AgTCNQ and CuTCNQ nanowires. They should have great potential in vacuum device applications.

Journal Article↗

PubMed2005

[Embryonic stem cell test in screening of medicine and other chemicals].

The technique of embryonic stem cell test (EST) has been developed and used in vitro to screen new medicines and other chemicals. According to toxicity, such medicines and chemicals can be classified as: non-toxic, weak toxic and/or strong toxic. EST shows merits such as no requirement of the sacrifice of pregnant animals, no side-effects on human or animals for candidate medicines and chemicals, higher sensitivity of embryonic stem cells when compared with the sensitivity of ordinary tissues of adult samples in toxicologic researches, higher accuracy when combined with computing techniques, and possible quantitation based on techniques of molecular biology. Advances in utility of EST technique were reviewed and the prospect of technique was also discussed in this paper.

Animal Testing Alternatives↗

PubMed2005

[The integrin beta1 mRNA changes after orthodontic movement of teeth in periodontitis rats].

OBJECTIVE: To study the integrin beta1 mRNA changes after orthodontic tooth movement in normal teeth and periodontitis teeth of rats. METHODS: The OD of positively stained osteoclasts for integrin beta1 mRNA using in situ hybridzation was detected after orthodontic tooth movement in normal teeth and periodontitis teeth groups. RESULTS: Integrin beta1 mRNA expression were detected on all osteoclasts in tooth movement samples of normal and periodontitis teeth. There were stronger positive signals after given orthodontic force in both of the two groups. But no differences were found after 0.5, 1, 2, 3, 5, 7, 10 days since orthodontic tooth movement. The integrin beta1 mRNA signals in normal tooth movement group were not different from that in periodontitis group. CONCLUSION: The integrin beta1 of osteoclasts may play a role in the stability and remodeling of periodontal ligament in orthodontic tooth movement. There were no difference in the OD of integrin beta1 mRNA staining in orthodontic tooth movement between normal teeth group and periodontitis teeth group.

Animals↗

PubMed2005

[Influence of basic fibroblast growth factors on the migration, proiferation of osteoblasts and periodontal ligament fibroblasts].

OBJECTIVE: In order to determine the influence of bFGF on the biological characteristics of osteoblasts and periodontal ligament cells, the author investigate the influence of bFGF on the migration, proliferation of osteoblasts and periodontal ligament fibroblasts between osteoblasts and fibroblasts. METHODS: The forth generation of osteoblasts and periodontal ligament fibroblast were obtained and the wounding model in vitro of them was founded. The cells were cultured in mediums with or without bFGF. Their migration and proliferation were observed and measured. RESULTS: Osteoblasts migrated faster than fibroblasts in common culture medium without bFGF and the periodontal ligament fibroblasts in culture medium with bFGF had higher migration rate than other groups. bFGF promoted the proliferation of both two kinds of cells. CONCLUSION: bFGF could accelerate periodontal fibroblasts' proliferation and migration.

Cell Proliferation↗

PubMed2005

[Construction of an engineered Acidithiobacillus caldus with high-efficiency arsenic resistance].

Using the recombinant technique in vitro, a new arsenic resistance plasmid pSDRA4 was constructed by subcloning the arsenic resistance genes from plasmid pUM3 into the wide-host-range IncQ plasmid pMMB24 with the hybrid trp-lac ( tac ) promoter, and followed by deleting the regulative gene of the promoter, the lacIQ gene. Then plasmid pSDRA4 was introduced from E. coli into extremely acidophilic obligately chemolithotrophic Acidithiobacillus caldus by conjugative transfer with a frequency of( 1.444 +/- 0.797) x 10(-4), and the engineered strain of Acidithiobacillus caldus (pSDRA4) for biomining was constructed. The successful transfer demonstrates the development of a conjugational system between strains of E. coli and A. caldus. The recombinant plasmid pSDRA4 is stable in A. caldus. Compared with wild type A. caldus, the level of the arsenic resistance of A. caldus (pSDRA4) is greatly raised from 10mmol/L to 45mmol/L.

Acidithiobacillus↗

PubMed2005

[Cell-surface hydrophobicity and degradation characteristics of hydrophobic hydrocarbon degrading bacteria].

Three high efficient hydrocarbon degrading bacteria named HDB-1, HDB-2, HDB-3 were separated from the oil contaminant soil. This paper studied on the cell-surface hydrophobicity of these three bacteria and environment influence factor by MATH,and the results show that the xylene-water two-phase system is suitable for studying the cell-surface hydrophobicity of three bacteria; the cell-surface hydrophobicities of HDB-1, HDB-2 and HDB-3 are respectively 68.8%, 57.4% and 64.1%; the hydrophobicity changed with the difference of cultivation and time,carbon source, temperature and pH value; the removal ratio of 1 000 mg/L oil content for 6 day can reach 91.6%, 64.5% and 79.8%. The hydrophobicity is related definitely with the degradation of the organic pollutant, and the degradation rate of hydrophobic organic by the bacteria of high hydrophobicity is quicker than that by the bacteria of low hydrophobicity.

Bacteria↗

PubMed2005

[Determination of hedychenone in Hedychium yunnanense].

OBJECTIVE: To establish an HPLC method for determination of hedychenone in Hedychium yunnanense. METHOD: C18 Chromatographic column was used, acetonitrile-water (9:1) as mobile phase, at flow rate of 1.0 mL x min(-1): The wavelength for detection was 235 nm. RESULT: The linear range of hedychenone was 5.92-29.6 microg x mL(-1)(r = 0.9999). The average recovery was 99.0%, RSD of precision was less than 2%. CONCLUSION: The method is simple, effective and feasible, and can be used to evaluate the quality of the herb.

Chromatography, High Pressure Liquid↗

PubMed2005

[Influences of applying force during the different stages of estrous cycle on orthodontic tooth movement of rats].

OBJECTIVE: To explore the effects of applying force during the different stages of estrous cycle on orthodontic tooth movement of rats, so as to offer an experimental princinple for women's orthodontic treatment. METHODS: 80 female 3-month-old Wistar rats, which had a stable and five-day estrous cycle, were used. They were randomly divided into control groups and loading-force groups. Each group was divided again into 4 sub-groups according to the different stages of the estrous cycle. The loading-force groups received repeated intermittent orthodontic force for four times seperately during the same stage of the estrous cycle. The distance between upper incisor and the first molar on the left was measured. The data were analyzed by One-way ANOVA, S-N-K. RESULTS: There were significant variations in the amount of tooth movement among the groups which received the mechanical force during the different stages of the estrous cycle (P <0.01). There were significant variations in the amount of tooth movement between the groups received force during pre-estrus and estrus (P <0.05). There were not significant variations between the groups received force during metestrus and diestrus (P > 0.05). The largest amount of tooth movement was in estrus group and smallest in pre-estrus one. CONCLUSION: The effect of tooth movement depended on which stage of estrous cycle was chosen to be the time of applying orthodontic force.

Analysis of Variance↗

PubMed2004

Mouse brain organization revealed through direct genome-scale TF expression analysis.

In the developing brain, transcription factors (TFs) direct the formation of a diverse array of neurons and glia. We identifed 1445 putative TFs in the mouse genome. We used in situ hybridization to map the expression of over 1000 of these TFs and TF-coregulator genes in the brains of developing mice. We found that 349 of these genes showed restricted expression patterns that were adequate to describe the anatomical organization of the brain. We provide a comprehensive inventory of murine TFs and their expression patterns in a searchable brain atlas database.

Animals↗

PubMed2004

Oxidation of phosphatidylserine: a mechanism for plasma membrane phospholipid scrambling during apoptosis?

Selective oxidation of phosphatidylserine (PS) during apoptosis precedes its externalization in plasma membrane and is essential for the engulfment of apoptotic cells. To experimentally test whether PS oxidation stimulates its externalization via its effects on aminophospholipid translocase (APT) or by enhanced PS scrambling, action of oxidized PS (PSox) was studied using leukemia HL-60 cells and lymphoma Raji cells. Both PS and PSox were equally well recognized by APT. PSox did not inhibit APT. Rate of transmembrane PS diffusion was fourfold higher in cells with integrated PSox than with PS. Thus, PSox acts as a "non-enzymatic scramblase" likely contributing to PS externalization.

Adenosine Triphosphate↗

PubMed2004

Raman spectroscopy of carbon-nanotube-based composites.

Recent developments in the application of Raman spectroscopy to carbon-nanotube-based composite materials are reviewed. This technique may be used to identify carbon nanotubes, access their dispersion in polymers, evaluate nanotube/matrix interactions and detect polymer phase transitions. The Raman spectra of nanotubes can also be used to quantify the strain or stress transferred to nanotubes from the surrounding environment and to investigate local stresses and strains in polymers and composites. A polarized Raman technique was developed to detect the stress or strain in a matrix using randomly dispersed single-walled nanotubes. This technique has been used to detect and map stress fields in model fibre-polymer composites. The stress distributions around fibre breaks were mapped and compared with classical load transfer models.

Carbon↗

PubMed2004

Morphological variation of individual Escherichia coli 50S ribosomal subunits in situ, as revealed by cryo-electron tomography.

Electron tomography (ET) has been used to reconstruct in situ individual 50S ribosomal subunits in Escherichia coli rifampicin-treated cells. Rifampicin inhibits transcription initiation. As a result, rapid degradation of preformed mRNA and dissociation of 70S ribosomes give accumulation of free subunits. In the 50S subunit, the L1 stalk, the L7/L12 stalk, the central protuberance (CP), and the peptidyl transferase center (PTC) cleft are the most dynamic and flexible parts in the reconstructed structures with clear movements indicated. Different locations of the tunnel in the central cross-sections through the in situ 50S subunits indicate the flexible nature of the pathway inside the large ribosomal subunit. In addition, gross morphological heterogeneity was observed in the reconstructions. Our results demonstrate a considerable structural variability among individual 50S subunits in the intracellular environment.

Computer Simulation↗