Biomedical subjects

Ting Wang

Publications and source records attributed to Ting Wang.

At least 73 records · Page 4Linked to original sources

PubMed2005

[Health damage of indoor air pollution by decoration on residents].

OBJECTIVE: To explore the health damage of indoor air pollution on residents by detecting the major indoor air pollutants and surveying the health indexes of residents. METHODS: 159 decorated houses were divided into 2 groups by whether the concentration of formaldehyde exceeded national standard. To analyze the health damage of formaldehyde and TVOC on residents, respectively. RESULTS: The concentrations of formaldehyde of the over standard group and the corresponding under standard group were (0.170 +/- 0.075) mg/m3 and (0.064 +/- 0.022) mg/m3, the concentrations of TVOC of the over standard group and the corresponding under standard group were (2.033 +/- 1.161) mg/m3 and (0.271 +/- 0.142) mg/m3. The incidence of the fatigue, nausea, eye symptoms, symptoms of nose, throat dessication, skin dessication, skin itching sensation and red swelling of the skin of the over standard group was significantly increased than that of the corresponding under standard group (P < 0.05). The incidence of the nausea, skin itching sensation and breathe hard of the TVOC over standard group was significantly increased than that of the corresponding under standard group (P < 0.05). CONCLUSION: Formaldehyde or TVOC will cause severe health damage.

Air Pollution, Indoor↗

PubMed2005

[Isolation and characterization of a HCH degradation Sphingomanas sp. stain BHC-A].

An aerobic bacterium was isolated successfully from a long-term contaminated upland field, which was named BHC-A. The bacterium can utilize Hexachlorocycloexane as a sole carbon source and decompose this substance rapidly and completely. According to its physiological & biochemical characters and the homology analysis of its 16S rDNA sequence, this strain was identified as Sphingomonas sp. Stain BHC-A canmineralize not only alpha, gamma and delta-HCH rapidly, but also 5 mg/L beta-HCH in 12h completely. However, Sphingomonas paucimobilis UT26, a gamma-HCH-decomposing bacterium, can only degrade 12.6% of 5 mg/L alpha-HCH, but not beta-HCH and delta-HCH, even for more than 24h in the medium. The seedling of cucumber was selected as the model plant subject to the inhibition of HCH to the growth of cucurbitaceous plants. The results shows that the degradation of HCH isomers by BHC-A in soil is even steady and excellent, that BHC-A can eliminate the contamination of the soil and the harm to the plants.

Biodegradation, Environmental↗

PubMed2005

[Protective effects of total flavonoids of Broussonetia papyrifera on oxidative injury of ultraviolet A to human keratinocytes].

OBJECTIVE: To investigate the oxidative damage of ultraviolet A (UVA) to human immortalized keratinocytes line HaCaT and the protective effects of total flavonoids of Broussonetia papyrifera (TFBP) gotten from the leaves of broussonetia papyifera. METHODS: Based on the culture of the human keratinocytes, the experiment group added with different dosages of TFBP before exposure to the radiation, received the UVA radiation together with the treatment group. The levels of malondialdehyde (MDA) and the activities of superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) were determined in cultured HaCaT cells as well as the cell activity with MTT reduction assay. Human immortalized keratinocytes HaCaT cells received ultraviolet A with the different dosages between 0.46 and 2.76 J/cm(2) respectively. The protective effects of TFBP at different concentrations were also evaluated. RESULTS: The cell activity decreased gradually from 96.3% to 37.5% with the increase of UVA dosage from 0.46 J/cm(2) to 2.76 J/cm(2). After 10 mg/L up to 200 mg/L of TFBP were added the cell activity increased, the levels of MDA decreased from (5.14 +/- 0.58) nmol/mg pro to (2.98 +/- 0.14) nmol/mg pro, the levels of SOD increased from (23.09 +/- 3.91) U/mg pro to (34.50 +/- 1.59) U/mg pro and the activity of GSH-Px increased somewhat. CONCLUSION: Ultraviolet A causes significant oxidative injury to HaCaT cells under the conditions of this study. TFBP gotten from the leaves of broussonetia papyrifera has certain protective effect on HaCaT epithelial cells.

Antioxidants↗

PubMed2005

[Isolation and characteristic of a moderately halophilic bacterium accumulated ectoine as main compatible solute].

A moderately halophilic bacterium(designated strain I15) was isolated from lawn soil. Based on the analysis of 16S rDNA (GenBank accession number DQ010162), morphology, physiological and biochemical characteristics, strain I15 was identified as Virgibacillus marismortuii. This strain was capable of growing under 0% approximately 25% NaCl, and exhibited an optimum NaCl concentration of 10% and an optimum temperature of 30 degrees C and an optimum pH of 7.5 - 8.0 for its growth, respectively. Under hyperosmotic stress, strain 115 accumulated ectoine as the main compatible solute. Under 15% NaCl conditions the intracellar ectoine can reach to 1.608 mmol/(g x cdw), accounted for 89.6% of the total compatible solutes. The biosynthesis of ectoine was under the control of osmotic, and the accumulated ectoine synthesized intraceilularly can released under hypoosmotic shocks and resynthesis under hyperosmotic shock rapidly.

Amino Acids, Diamino↗

PubMed2004

Genetic differentiation of relictual populations of Alsophila spinulosa in southern China inferred from cpDNA trnL-F noncoding sequences.

The genetic differentiation and phylogeographical pattern of 11 relictual populations of Alsophila spinulosa distributed across Hainan, Guangdong, and Guangxi in southern China were inferred from sequence variations of trnL-F noncoding regions of chloroplast DNA (cpDNA). The length of trnL-F noncoding sequences varied from 863 to 940 bp. The A + T content was 62.23-63.36%. Sequences were neutral in terms of evolution (Tajima's criterion D=-0.62417, P>0.10 and Fu and Li's test D*=-1.45455, P>0.10; F*=-1.32798, P>0.10). Thirty-four haplotypes were identified based on nucleotide variation. Relatively high levels of haplotype diversity (h=0.929) and nucleotide diversity (Dij=0.022263) were detected in A. spinulosa, probably associated with its long evolutionary history which allowed the accumulation of genetic variation within lineages. Both the minimum spanning network and the strict consensus tree of the most parsimonious trees generated for haplotypes demonstrated that the investigated populations of A. spinulosa were subdivided into two geographical groups: Hainan and Guangdong-Guangxi. An analysis of molecular variance (AMOVA) indicated that most of the genetic variation (87.48%, P<0.001) was partitioned among regions. Spatial structure measurements revealed that population genetic structure was not related to geographical distance. This research suggests that blocked gene flow by Qiongzhou strait and an inbreeding system might result in the geographical subdivision between Hainan and Guangdong-Guangxi (F(ST)=0.92, Nm=0.09). Within each region, the "star like" pattern of phylogeography of haplotypes implied a population expansion process during evolutionary history. Gene genealogies together with coalescent theory were useful tools for uncovering the phylogeography of A. spinulosa.

China↗

PubMed2004

Comparative structural and energetic analysis of WW domain-peptide interactions.

WW domains are small globular protein interaction modules found in a wide spectrum of proteins. They recognize their target proteins by binding specifically to short linear peptide motifs that are often proline-rich. To infer the determinants of the ligand binding propensities of WW domains, we analyzed 42 WW domains. We built models of the 3D structures of the WW domains and their peptide complexes by comparative modeling supplemented with experimental data from peptide library screens. The models provide new insights into the orientation and position of the peptide in structures of WW domain-peptide complexes that have not yet been determined experimentally. From a protein interaction property similarity analysis (PIPSA) of the WW domain structures, we show that electrostatic potential is a distinguishing feature of WW domains and we propose a structure-based classification of WW domains that expands the existent ligand-based classification scheme. Application of the comparative molecular field analysis (CoMFA), GRID/GOLPE and comparative binding energy (COMBINE) analysis methods permitted the derivation of quantitative structure-activity relationships (QSARs) that aid in identifying the specificity-determining residues within WW domains and their ligand-recognition motifs. Using these QSARs, a new group-specific sequence feature of WW domains that target arginine-containing peptides was identified. Finally, the QSAR models were applied to the design of a peptide to bind with greater affinity than the known binding peptide sequences of the yRSP5-1 WW domain. The prediction was verified experimentally, providing validation of the QSAR models and demonstrating the possibility of rationally improving peptide affinity for WW domains. The QSAR models may also be applied to the prediction of the specificity of WW domains with uncharacterized ligand-binding properties.

Amino Acid Sequence↗

PubMed2004

The gut microbiota as an environmental factor that regulates fat storage.

New therapeutic targets for noncognitive reductions in energy intake, absorption, or storage are crucial given the worldwide epidemic of obesity. The gut microbial community (microbiota) is essential for processing dietary polysaccharides. We found that conventionalization of adult germ-free (GF) C57BL/6 mice with a normal microbiota harvested from the distal intestine (cecum) of conventionally raised animals produces a 60% increase in body fat content and insulin resistance within 14 days despite reduced food intake. Studies of GF and conventionalized mice revealed that the microbiota promotes absorption of monosaccharides from the gut lumen, with resulting induction of de novo hepatic lipogenesis. Fasting-induced adipocyte factor (Fiaf), a member of the angiopoietin-like family of proteins, is selectively suppressed in the intestinal epithelium of normal mice by conventionalization. Analysis of GF and conventionalized, normal and Fiaf knockout mice established that Fiaf is a circulating lipoprotein lipase inhibitor and that its suppression is essential for the microbiota-induced deposition of triglycerides in adipocytes. Studies of Rag1-/- animals indicate that these host responses do not require mature lymphocytes. Our findings suggest that the gut microbiota is an important environmental factor that affects energy harvest from the diet and energy storage in the host. Data deposition: The sequences reported in this paper have been deposited in the GenBank database (accession nos. AY 667702--AY 668946).

Adipocytes↗

PubMed2004

Determining beta-sheet stability by Fourier transform infrared difference spectra.

We describe here a new method for determining the conformational stability of antiparallel beta-sheets. Due to coupling between the transition dipoles, beta-sheet conformations typically exhibit a characteristic high-frequency amide I component centered at approximately 1680 cm(-1). Using one beta-sheet protein and two small beta-hairpins, we demonstrate that this high-frequency component, which is fairly narrow (approximately 8-10 cm(-1)), can be quantitatively resolved and used in thermal stability determination. Compared with the commonly used CD and fluorescence techniques, this ir method offers advantages. Since the area of this high-frequency component is only proportional to the folded population, it eliminates the need for a priori information of the folded and unfolded baselines encountered in other methods. Thus, it is applicable to a variety of beta-sheet systems.

Magnetic Resonance Spectroscopy↗

PubMed2004

Population genetic structure and phylogeographical pattern of a relict tree fern, Alsophila spinulosa (Cyatheaceae), inferred from cpDNA atpB- rbcL intergenic spacers.

Sequences of chloroplast DNA (cpDNA) atpB- rbcL intergenic spacers of individuals of a tree fern species, Alsophila spinulosa, collected from ten relict populations distributed in the Hainan and Guangdong provinces, and the Guangxi Zhuang region in southern China, were determined. Sequence length varied from 724 bp to 731 bp, showing length polymorphism, and base composition was with high A+T content between 63.17% and 63.95%. Sequences were neutral in terms of evolution (Tajima's criterion D=-1.01899, P>0.10 and Fu and Li's test D*=-1.39008, P>0.10; F*=-1.49775, P>0.10). A total of 19 haplotypes were identified based on nucleotide variation. High levels of haplotype diversity (h=0.744) and nucleotide diversity (Dij=0.01130) were detected in A. spinulosa, probably associated with its long evolutionary history, which has allowed the accumulation of genetic variation within lineages. Both the minimum spanning network and neighbor-joining trees generated for haplotypes demonstrated that current populations of A. spinulosa existing in Hainan, Guangdong, and Guangxi were subdivided into two geographical groups. An analysis of molecular variance indicated that most of the genetic variation (93.49%, P<0.001) was partitioned among regions. Wright's isolation by distance model was not supported across extant populations. Reduced gene flow by the Qiongzhou Strait and inbreeding may result in the geographical subdivision between the Hainan and Guangdong + Guangxi populations (FST=0.95, Nm=0.03). Within each region, the star-like pattern of phylogeography of haplotypes implied a population expansion process during evolutionary history. Gene genealogies together with coalescent theory provided significant information for uncovering phylogeography of A. spinulosa.

Biological Evolution↗

PubMed2004

Study of the interactions between tetracycline analogues and lysozyme.

The interactions between tetracycline analogues (oxytetracycline, doxycycline, methacycline) and lysozyme (LYSO) were studied by using UV-visible absorption and spectrofluorimetric method. Tetracycline analogues can make LYSO's fluorescence quenching. The quenching mechanism is static quenching. Absorption spectrum and quenching constant all support this conclusion. The binding constants of tetracycline analogues with LYSO were obtained at various temperatures. According to the Förster nonradiative energy transfer theory, we can get the distances of donators and acceptors. We also determined the main acting force between them is electrostatic gravitation according to the thermodynamic parameter.

Muramidase↗

PubMed2004

RNA interference of achaete-scute homolog 1 in mouse prostate neuroendocrine cells reveals its gene targets and DNA binding sites.

We have previously characterized a transgenic mouse model (CR2-TAg) of metastatic prostate cancer arising in the neuroendocrine (NE) cell lineage. Biomarkers of NE differentiation in this model are expressed in conventional adenocarcinoma of the prostate with NE features. To further characterize the pathways that control NE proliferation, differentiation, and survival, we established prostate NE cancer (PNEC) cell lines from CR2-TAg prostate tumors and metastases. GeneChip analyses of cell lines harvested at different passages, and as xenografted tumors, indicated that PNECs express consistent features ex vivo and in vivo and share a remarkable degree of similarity with primary CR2-TAg prostate NE tumors. PNECs express mAsh1, a basic helix-loop-helix (bHLH) transcription factor essential for NE cell differentiation in other tissues. RNA interference knockdown of mAsh1, GeneChip comparisons of treated and control cell populations, and a computational analysis of down-regulated genes identified 12 transcriptional motifs enriched in the gene set. Affected genes, including Adcy9, Hes6, Iapp1, Ndrg4, c-Myb, and Mesdc2, are enriched for a palindromic E-box motif, CAGCTG, indicating that it is a physiologically relevant mAsh1 binding site. The enrichment of a c-Myb binding site and the finding that c-Myb is down-regulated by mAsh1 RNA interference suggest that mAsh1 and c-Myb are in the same signaling pathway. Our data indicate that mAsh1 negatively regulates the cell cycle (e.g., via enhanced Cdkn2d, Bub1 expression), promotes differentiation (e.g., through effects on cAMP), and enhances survival by inhibiting apoptosis. PNEC cell lines should be generally useful for genetic and/or pharmacologic studies of the regulation of NE cell proliferation, differentiation, and tumorigenesis.

Animals↗

PubMed2004

A global suppressor motif for p53 cancer mutants.

The transcription factor and tumor suppressor protein p53 is frequently inactivated in human cancers. In many cases, p53 gene mutations result in high levels of inactive, full-length p53 protein with one amino acid change in the core domain that recognizes p53 DNA-binding sites. The ability to endow function to mutated p53 proteins would dramatically improve cancer therapy, because it would reactivate a central apoptotic pathway. By using genetic strategies and p53 assays in yeast and mammalian cells, we identified a global suppressor motif involving codons 235, 239, and 240. These intragenic suppressor mutations, either alone or in combination, restored function to 16 of 30 of the most common p53 cancer mutants tested. The 235-239-240 suppressor motif establishes that manipulation of a small region of the core domain is sufficient to activate a large number of p53 cancer mutants. Understanding the structural basis of the rescue mechanism will allow the pursuit of small compounds able to achieve a similar stabilization of p53 cancer mutants.

Animals↗

PubMed2004

Involvement of chloride channels in hepatic copper metabolism: ClC-4 promotes copper incorporation into ceruloplasmin.

BACKGROUND & AIMS: Copper transport in hepatocytes is regulated by the interaction of multiple pumps, chaperones, and accessory proteins. Intracellular chloride channels are essential for copper metabolism in yeast but their role in Cu transport in hepatocytes is unknown. The aim of this study was to determine whether chloride channels are modulators of copper incorporation into ceruloplasmin (CP). METHODS: The effects of chloride concentration and chloride channel expression on secretion of holoCp and apoCp was measured by gel electrophoresis and immunoblotting. ClC family chloride channel expression in hepatocytes was determined by Western blotting. The association of ClC-4 and the Wilson's disease protein (ATP7B) was determined by co-immunoprecipitation. RESULTS: Chloride substitution reduced total Cp secretion and the ratio of secreted holoCp to apoCp (P = 0.038). The role of specific chloride channels was examined by cotransfection of ceruloplasmin and the chloride channel. Overexpression of ClC-4 doubled copper incorporation into ceruloplasmin (P = 0.011), whereas identical overexpression of ClC-3 had no effect. The effect of ClC-4 was most pronounced under copper-limiting conditions in which it increased copper incorporation more than 4-fold (P = 0.037). ClC-4 protein was abundant in hepatocyte membranes and was localized in intracellular vesicles containing ATP7B. CONCLUSIONS: ClC-4 is an intracellular chloride channel that stimulates copper incorporation into ceruloplasmin, probably by improving the efficiency of the ATP7B copper pump. It is thus an important component of the regulation of hepatic copper transport and may modulate Cu transport rates during copper deficiency, Wilson's disease, and other copper toxicosis syndromes.

Adenosine Triphosphatases↗

PubMed2004

Small physiologic changes in calcium and magnesium alter excitability and burst firing of CA1 pyramidal cells in rat hippocampal slices.

The effects of small physiologic changes in Ca and Mg concentrations on neuronal burst firing were examined. Intracellular electrophysiologic recordings were made from CA1 pyramidal neurons in rat hippocampal slices. There was no difference in the resting potential or the input resistance of neurons bathed in the lower Ca-Mg artificial Cerebrospinal fluid (aCSF) (1.4 mM Ca; 1.3 mM Mg) compared with the higher Ca-Mg aCSF (2 mM Ca; 2 mM Mg). However, neurons in the lower Ca-Mg aCSF, but not the higher Ca-Mg aCSF, demonstrated depolarizing waves and bursts of action potentials; no single component of the aCSF accounted for this difference. Reducing the Ca from 2 to 1 mM in the higher Ca-Mg aCSF increased the mean frequency of action potentials from 28 to 171 Hz; the addition of 6-cyano-7-nitroquinoxaline-2,3-dione did not reduce the frequency. The threshold of potassium for inducing bursts was 5.25 with 1 mM Ca, 7.25 with 2 mM Ca, and 11.25 with 3 mM Ca. When Mg was reduced from 2 to 1 mM, the number of potassium-induced bursts increased to 190%; increasing Mg from 2 to 3 mM reduced the bursts to 58% (frequency with 2 mM Mg set to 100%). Small decreases in extracellular Ca and/or Mg led to increased excitability and burst firing, which may alter physiologic and pathophysiologic processes such as enhancing long-term potentiation, pain transmission, epileptogenesis, and neuronal damage and decreasing anesthetic potency. Increases in extracellular Ca and/or Mg would have the opposite effect on these processes. These effects of extracellular divalent ions on burst firing may explain some of the pathophysiologic effects of hypocalcemia and hypomagnesemia.

Action Potentials↗

PubMed2004

Genetic structure and variation in the relict populations of Alsophila spinulosa from southern China based on RAPD markers and cpDNA atpB-rbcL sequence data.

RAPD markers and sequences of chloroplast DNA (cpDNA) atpB-rbcL intergenic spacers were used to characterize the pattern of genetic variation and the phylogenetic relationships of the relict populations of Alsophila spinulosa located in Jian Feng Ling (JFL) and Diao Luo Shan (DLS), Hainan, and Tang Lang Shan (TLS), Ding Hu Shan (DHS), and Da Xi Shan (DXS), Guangdong, of southern China. 28 random primers generated 118 bands, out of which 26 (22.03%) were polymorphic loci, distinguishing 17 different RAPD phenotypes. Percentage of polymorphic loci, Shannon phenotypic diversity and Nei's gene diversity comprehensively indicated that JFL possessed the highest diversity, TLS and DHS in intermediate and DLS or DXS the least; the corresponding values of the population appeared correlated with the population size. Differentiation was detected among populations of A. spinulosa (1-Hpop/Hsp=0.7453, GST=0.7763, and phist=0.8145). AMOVA showed that 47.44% of the variance was partitioned among regions (Hainan and Guangdong), 34.01% attributed among populations within regions, whereas only 18.55% occurring within populations. Low level of intra-specific diversity was maintained in A. spinulosa with Shannon diversity and gene diversity merely 0.0560 and 0.0590, repectively. Sequence length of atpB-rbcL intergenic spacer varied from 724 bp to 730 bp. Base composition was with A+T content between 63.17% and 63.70%. 13 haplotypes of atpB-rbcL noncoding spacers were identified. UPGMA dendrogram of RAPD phenotypes, principal components analysis based on RAPD patterns, minimum spanning network and neighbour-joining (NJ) tree established on atpB-rbcL haplotypes consistently suggested the geographical subdivision of populations of A. spinulosa between Hainan and Guangdong. Breeding system and conservation strategy of A. spinulosa was discussed based on the information of population genetic structure and variation.

Base Composition↗

PubMed2004

How optimal are the binding energetics of barnase and barstar?

The extracellular ribonuclease barnase and its intracellular inhibitor barstar bind fast and with high affinity. Although extensive experimental and theoretical studies have been carried out on this system, it is unclear what the relative importance of different contributions to the high affinity is and whether binding can be improved through point mutations. In this work, we first applied Poisson-Boltzmann electrostatic calculations to 65 barnase-barstar complexes with mutations in both barnase and barstar. The continuum electrostatic calculations with a van der Waals surface dielectric boundary definition result in the electrostatic interaction free energy providing the dominant contribution favoring barnase-barstar binding. The results show that the computed electrostatic binding free energy can be improved through mutations at W44/barstar and E73/barnase. Furthermore, the determinants of binding affinity were quantified by applying COMparative BINding Energy (COMBINE) analysis to derive quantitative structure-activity relationships (QSARs) for the 65 complexes. The COMBINE QSAR model highlights approximately 20 interfacial residue pairs as responsible for most of the differences in binding affinity between the mutant complexes, mainly due to electrostatic interactions. Based on the COMBINE model, together with Brownian dynamics simulations to compute diffusional association rate constants, several mutants were designed to have higher binding affinities than the wild-type proteins.

Algorithms↗

PubMed2004

[Study on the relationship between [Ca2+]i and the MDR formation in K562/A02 cells].

To explore the relationship of multidrug resistance formation in K562/A02 cells with the intracellular concentration of [Ca(2+)]i, the cytotoxicities of daunorubicin (DNR) were assayed by MTT method, the variations of [Ca(2+)]i of K562 cells and K562/A02 cells after treatment of Tet, DRL and DNR alone or in combination were detected by using Fura-2/AM. The results showed as follows: (1) The cytotoxicities of DNR to cell line K562/A02 were enhanced by 1 micro mol/L Tet or 5 micro mol/L DRL. Their IC(50) was (7.28 +/- 2.06) micro g/ml and (7.58 +/- 3.44) micro g/ml; multiple of their reversal effect was 2.94 and 2.82, but IC(50) of combined Tet and DRL was (1.66 +/- 0.41) micro g/ml. Its reverse effect distinctly increased by 12.9 times. (2) The [Ca(2+)]i in K562/A02 cells were higher than that in K562 cells. (3) One micro mol/L Tet and 5 micro mol/L DRL alone increased the [Ca(2+)]i in K562/A02 cells time-dependently and there was antagonism when both were used. It is concluded that high [Ca(2+)]i is supposed to be a reason of MDR in K562/A02 cells, the action of resistance modifying agents (RMA) in MDR reverse course, however, needs further research.

Alkaloids↗

PubMed2004

[Reversal effect of tetrandrine in combination with droloxifene on cell line K562/A02 and its correlation with inducted apoptosis].

To study the correlation of the reversal effect of tetrandrine (Tet) in combination with droloxifene (DRL) on multidrug resistant cell line K562/A02 and induction apoptosis, the apoptosis of K562 cells and K562/A02 cells after the treatment of Tet and DRL alone or their combination was detected by flow cytometry (FCM). The results showed 0.62 microg/ml Tet and 1.94 microg/ml DRL alone could induce apoptosis of K562 cells in time-dependent manner after culture for 48 hours. Neither Tet at 0.62 microg/ml nor DRL at 1.94 microg/ml alone could induce apoptosis of K562/A02 cells, but in the combination of them two induced apoptosis of few K562/A02 cells in culture for 72 hours. In conclusion, the mechanism of Tet and DRL reversing multidrug resistance has no correlation with the apoptosis of K562/A02 cells.

Alkaloids↗