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Biomedical subjects

Jie Zhang

Publications and source records attributed to Jie Zhang.

At least 91 records · Page 5Linked to original sources
PubMed2006

Engineered Bacillus thuringiensis GO33A with broad insecticidal activity against lepidopteran and coleopteran pests.

A recombinant plasmid pSTK-3A containing cry3Aa7 gene encoding a coleopteran-specific insecticidal protein was constructed and introduced into wild Bacillus thuringiensis subsp. aizawai G03, which contained cry1Aa, cry1Ac, cry1Ca, and cry2Ab genes and was highly toxic to lepidopteran insect pests. The genetically engineered strain were named G033A. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis and Western blot analysis demonstrated that the cry3Aa7 gene was expressed normally and produced a 67 kDa protein in G033A, and the flat rectangular crystals of Cry3Aa7 toxin protein was observed under scanning electron microscope. The recombinant plasmid was maintained in bacteria cultured for 180 generations in culture media containing no antibiotics. Synthesis of the Cry3Aa7 toxin conferred high and broad toxicity to the recombinant strain G033A against coleopteran order, elm leaf beetle (Pyrrhalta aenescens) (LC(50) 0.35 mg/ml), for which the parental strain G03 was not toxic. Both the parental strain G03 and recombinant strain G033A showed strong insecticidal activity to lepidopteran pests, beet armyworm (Spodoptera exigua), diamondback moth (Plutella xylostella), and cotton bollworm (Helicoverpa amigera), respectively. The lethal concentration 50% (LC(50)) of G033A against S. exigua, P. xylostella, and H. amigera was 4.26, 0.86, and 1.76 microg/ml, respectively.

Animals↗
PubMed2006

Anticancer activity of litchi fruit pericarp extract against human breast cancer in vitro and in vivo.

Litchi fruit pericarp (LFP) extract contains significant amounts of polyphenolic compounds and exhibits powerful antioxidative activity against fat oxidation in vitro. The purpose of this study is to confirm the anticancer activity of LFP extract on human breast cancer in vitro and in vivo, and to elucidate the mechanism of its activity. Human breast cancer cells were tested in vitro for cytotoxicity, colony formation inhibition, BrdU incorporation, and gene expression profiling after treatment with LFP extract. Seven nude mice bearing human breast infiltrating duct carcinoma orthotopically were tested for its anticancer activity and expression of caspase-3 in vivo by oral administration of 0.3% (0.3 mg/ml) of LFP water-soluble crude ethanolic extract (CEE) for 10 weeks. LFP extract demonstrated a dose- and time-dependent inhibitory effect on cell growth (IC(50) = 80 microg/ml), and it significantly inhibited colony formation and BrdU incorporation of human breast cancer cells. Oligonucleotide microarray analysis identified 41(1.22%) up-regulated and 129 (3.84%) down-regulated genes after LFP water-soluble CEE treatment; the predominantly up-regulated genes were involved in various biological functions including cell cycle regulation and cell proliferation, apoptosis, signal transduction and transcriptional regulation, and extracellular matrix/adhesion molecules; and down-regulated genes were mainly associated with adhesion, invasion, and malignancy of cancer cells. A 40.70% tumor mass volume reduction and significant increase of casepase-3 protein expression were observed in vivo experiment. The findings in this study suggested that LFP extract might have potential anticancer activity on both ER positive and negative breast cancers, which could be attributed, in part, to its DNA damage effect, proliferating inhibition and apoptosis induction of cancer cells through up-regulation and down-regulation of multiple genes involved in cell cycle regulation and cell proliferation, apoptosis, signal transduction and transcriptional regulation, motility and invasiveness of cancer cells; ADP-ribosyltransferase (NAD+; poly (ADP-ribose) polymerase)-like 1 (ADPRTL1), Cytochrome P450, subfamily I (CYP1A1) and Hyaluronan-mediated motility receptor (HMMR) might be the main molecular targets at which LFP water-soluble CEE acted.

Animals↗
PubMed2006

Experimental synchronization of independent entangled photon sources.

We report the generation of independent entangled photon pairs from two synchronized but mutually incoherent laser sources. The quality of synchronization is confirmed by observing a violation of Bell's inequality with 3.2 standard deviations in an entanglement swapping experiment. The techniques developed in our experiment are not only important for realistic linear optical quantum-information processing, but also enable new tests of local realism.

Journal Article↗
PubMed2006

[Induction of apoptosis by mifepristone in androgen-independent prostate cancer cell lines in vitro].

OBJECTIVE: To investigate the effects of mifepristone on cell proliferation of human androgen-independent prostate carcinoma cell lines DU-145, PC-3 in vitro and the possible mechanisms involved. METHODS: The A values of the prostate cancer cells DU-145 and PC-3 in each group with various concentrations (1, 10, 50, 100 micromol/L) of mifepristone at various time intervals (24-120 h) were detected with the colorimetric 3-(4, 5-dimethyl-2-thiazolyl)-2, 5-diphenyl tetrazolium bromide assay. The apoptosis rates of the DU-145 and PC-3 cells treated with 10 micromol/L of mifepristone for 24 h and 48 h were assessed by flow cytometry analysis technique. Immunohistochemical technique was used to determine the expression of bax, bcl-2 and vascular endothelial growth factor (VEGF) proteins after treatment with 10 micromol/L of mifepristone. RESULTS: The A values of the cancer cells treated with 1 micromol/L of mifepristone were similar to that of controls, while those of the cells treated with 10 micromol/L, 50 micromol/L and 100 micromol/L of mifepristone were significantly different from that of controls (P < 0.01). Mifepristone markedly inhibited cell proliferation of prostate cancer cells DU-145 and PC-3 on a dose- and time-depending manner. The apoptosis rates of 10 micromol/L mifepristone for DU-145 cell line at 24 h, 48 h were respectively 15.3%, 30.4% with flow cytometry method and then PC-3 cell line were respectively 22.2%, 32.0%. Immunohistochemical technique showed the expression of bcl-2 and VEGF in the DU-145 and PC-3 cells treated with 10 micromol/L of mifepristone were significantly decreased, and the expression of bax was increased. CONCLUSIONS: Mifepristone can induce apoptosis of androgen-independent prostate cancer cell lines DU-145 and PC-3 in vitro. The apoptosis effect is time-and-dose dependent. Mifepristone could initiate a cell death command via apoptotic pathways decreasing the expression of VEGF protein, downregulating the expression of bcl-2 protein and increasing the expression of bax protein.

Androgens↗
PubMed2006

Tumor inhibition and improved immunity in mice treated with flavone from Cirsium japonicum DC.

The purpose of these experiments is to study the effects of flavone from Cirsium japonicum DC (FLCJ) on tumor activity and on the regulation of the immune response in mice with S180 and H22 tumors. Pectolinarin and 5, 7-dihydroxy-6, 4'-dimethoxyflavone are two major components of FLCJ. FLCJ, pectolinarin and 5, 7-dihydroxy-6, 4'-dimethoxyflavone can inhibit the growth of the implanted tumors S180 and H22 and promote cellular and humoral immune responses. FLCJ is stronger than Pectolinarin and 5, 7-dihydroxy-6, 4'-dimethoxyflavone in inhibiting tumors and promoting immune response significantly. Our results indicated that the tumor inhibition of FLCJ had close relation with its regulation of the immune response Furthermore, this tumor inhibition by FLCJ may activate the innate immune system, which would be expected as a potential anti-tumor drug.

Animals↗
PubMed2006

Novel strategies to identify relevant molecular signatures for complex human diseases based on data of identical-by-decent profiles and genomic context.

OBJECTIVE: To develop novel strategies to identify relevant molecular signatures for complex human diseases based on data of identical-by-decent profiles and genomic context. METHODS: In the proposed strategies, we define four relevancy criteria for mapping SNP-phenotype relationships-point-wise IBD mean difference, averaged IBD difference for window, Z curve and averaged slope for window. RESULTS: Application of these criteria and permutation test to 100 simulated replicates for two hypothetical American populations to extract the relevant SNPs for alcoholism based on sib-pair IBD profiles of pedigrees demonstrates that the proposed strategies have successfully identified most of the simulated true loci. CONCLUSION: The data mining practice implies that IBD statistic and genomic context could be used as the informatics for locating the underlying genes for complex human diseases. Compared with the classical Haseman-Elston sib-pair regression method, the proposed strategies are more efficient for large-scale genomic mining.

Alcoholism↗
PubMed2006

Method for calibrating system parameters of a multidirectional interferometers system.

A multidirectional interferometer system has been proposed and developed to measure the position and orientation of a positioning stage. In this method the system parameters, such as positions of the corner-cube reflectors and directions of the rays in the interferometers, must be determined beforehand. However, it is difficult to find ways to determine the system parameters for each different system with necessary accuracy. This paper proposes a systematic method for calibrating the system parameters when the number of the interferometers is larger than the degrees of freedom of the stage. The method is verified for a two-dimensional stage by both simulation and experiment.

Journal Article↗
PubMed2006

Interaction of light filaments generated by femtosecond laser pulses in air.

The interaction of two light filaments propagating in air is simulated. Simulations show that the interaction of the two light filaments displays interesting features such as attraction, fusion, repulsion, and spiral propagation, depending on the relative phase shift and the crossing angle between them. A long and stable channel can be formed by fusing two in-phase light filaments. The channel becomes unstable with the increase of the crossing angle and phase shift. The interaction of two light filaments in different planes is studied and the spiral propagation is observed.

Journal Article↗
PubMed2006

Polymer effects on small- and large-scale two-dimensional turbulence.

We investigate the effect of dilute polymers on driven two-dimensional turbulence in a soap film. Transitions from strong to weak turbulence are identified by independently varying the polymer concentration phi and the energy injection rate epsilon(inj) . Studies of velocity structures in small scales reveal that strong saddles are suppressed, whereas weak ones become more populated. Interestingly, this redistribution of saddle points in turbulent flows strongly correlates with the quenching of velocity fluctuations on large scales, suggesting that this hydrodynamic structure may play a role in transferring energy from scale to scale.

Journal Article↗
PubMed2006

Advances in capillary electrophoretically mediated microanalysis: an update.

This review, as a continuation of an earlier report, gives an overview of recent developments, over the period from 2003 until now, in the use of capillary electrophoretic techniques for the in-line study of enzymatic reactions, derivatization, and chemical reactions. The article is divided into two parts: (i) in-line enzymatic reactions and (ii) in-line derivatization and chemical reactions. The first part introduces electrophoretically mediated microanalysis (EMMA) and discusses and illustrates the different modes of EMMA. A literature overview on enzymatic reactions is provided. The second part starts with an introduction of the procedures and the nomenclature used in the area of in-line derivatization and chemical reactions based on EMMA. Reported derivatization and chemical reaction procedures are discussed and summarized.

Electrophoresis, Capillary↗
PubMed2006

Interlaboratory study of a NACE method for the determination of R-timolol content in S-timolol maleate: assessment of uncertainty.

Analyses of statistical variance were applied to evaluate the precision and practicality of a CD-based NACE assay for R-timolol after enantiomeric separation of R- and S-timolol. Data were collected in an interlaboratory study by 11 participating laboratories located in Europe and North America. General qualitative method performance was examined using suitability descriptors (i.e. resolution, selectivity, migration times and S/N), while precision was determined by quantification of variances in the determination of R-timolol at four different impurity levels in S-timolol maleate samples. The interlaboratory trials were designed in accordance with the ISO guideline 5725-2. This allowed estimating for each sample, the different variances, i.e. between-laboratory (s2(Laboratories)), between-day (s2(Days)) and between-replicate (s2(Replicates)). The variances of repeatability (s2r) and reproducibility (s2R) were then calculated. The estimated uncertainty, derived from the precision estimates, seems to be concentration-dependent above a given threshold. This example of R-timolol illustrates how a laboratory can evaluate uncertainty in general.

Adrenergic beta-Antagonists↗
PubMed2006

Screening of drug metabolism by CE.

The use of CE for rapid assessment of metabolic stability of drugs with cytochrome P450 (CYP) enzymes, based on relative rates of reduced nicotinamide adenine dinucleotide phosphate (NADPH) consumption and nicotinamide adenine dinucleotide phosphate (NADP) production, was investigated. The separation conditions were as follows: capillary, 80.5 cm (75 microm id, 72 cm effective length for UV detection, 58 cm effective length for fluorescence detection); 25 mM sodium phosphate buffer (pH 8.8); 28 kV (80 microA) applied voltage; UV, 260 nm; fluorescence detection, excitation wavelength, 310 nm, emission wavelength, 418 nm; capillary temperature, 25 degrees C. For UV detection, the incubation conditions were as follows: CYP3A4: 20 pmol/mL; NADPH: 1 mM; EDTA: 1 mM; concentration of the substrate: 5-10 times its reported literature K(m) value; temperature: 37 degrees C; incubation time: 15 min. For fluorescence detection, the concentrations were reduced to CYP3A4: 4 pmol/mL, NADPH: 20 microM, EDTA: 20 microM and substrate: 10 microM. Blank incubations were performed in the absence of substrate. Compared with the blank, significant differences were found for the consumption of NADPH and the production of NADP. The development of this assay system allows rapid assessment of metabolic stability relative to standard compounds, as well as potential identification of the major CYP involved in the metabolism. It would reduce the backlog of compounds that require LC/MS analysis, and thereby expedite the process of metabolic stability screening.

Cytochrome P-450 CYP3A↗
PubMed2006

On-line hyphenation of supercritical fluid extraction and two-dimensional high performance liquid chromatography-atmospheric pressure chemical ionization tandem mass spectrometer for the analysis of Ganoderma lucidum.

A novel on-line system combining supercritical fluid extraction (SFE) and two-dimensional high performance liquid chromatography (2D-HPLC) was developed. A trap column and two three-port valves were employed to couple SFE and 2D-HPLC system, which was composed of a CN column and a monolithic silica column, connected by a 10-port dual-position valve. The analytes extracted by supercritical CO2 were completely transferred to the 2D-HPLC system. After separation in two orthogonal modes, the eluents were delivered to APCI-tandem-MS for identification of the samples. In this way, sample preparation, separation, detection, and identification were integrated into an on-line system permitting analysis of the fruiting bodies of Ganoderma lucidum, and at least 73 components in the extract were resolved with calculated peak capacity of up to 1643.

Acetonitriles↗
PubMed2006

The NMR studies on two new furostanol saponins from Agave sisalana leaves.

The detailed NMR studies and full assignments of the 1H and 13C spectral data for two new furostanol saponins isolated from Agave sisalana leaves are described. Their structures were established using a combination of 1D and 2D NMR techniques including 1H, 13C, 1H-1H COSY, TOCSY, HSQC, HMBC and HSQC-TOCSY, and also FAB-MS spectrometry and chemical methods. The structures were established as (25S)-26-(beta-D-glucopyranosyl)-22 xi-hydroxyfurost-12-one-3beta-yl-O-alpha-L-rhamnopyranosyl-(1-->4)-beta-D-glucopyranosyl-(1-->3)-O-[O-beta-D-glucopyranosyl-(1-->2)]-O-beta-D-glucopyranosyl-(1-->4)-beta-D-galacto- pyranoside (1) and (25S)-26-(beta-D-glucopyranosyl)-22xi-hydroxyfurost-5-en-12-one-3beta-yl-O-alpha-L-rhamno- pyranosyl-(1-->4)-beta-D-glucopyranosyl-(1-->3)-O-[O-beta-D-glucopyranosyl-(1-->2)]-O-beta-D-glucopyranosyl- (1-->4)-beta-D-galactopyranoside (2).

Agave↗
PubMed2006

Expressed proteome analysis of human hepatocellular carcinoma in nude mice (LCI-D20) with high metastasis potential.

We report for the first time an expressed proteome for human hepatocellular carcinoma (HCC) in nude mice model. Most cases of human liver cancer are HCC with highly metastatic ability. Therefore, the early prediction or diagnosis and effective treatment are the key points of research. We have previously successfully established a human HCC nude mice model (LCI-D20) with high metastasis potential. To understand better the tumor biology of HCC it is worth to explore the relativity of all expressed protein profiles in the LCI-D20 HCC nude mice model. With advanced proteomics technologies, we have carried out a proteomic analysis with following stages: protein sample preparation of cancer tissue, including total cellular extraction and sequential fractionation, 2-DE and 2-D LC separation, ESI/MALDI-MS/MS identification, as well as data-dependent bioinformatics. The identified proteins were classified bioinformatically respective to their function, biological process and intracellular localization. Some important proteins found in HCC, e.g. metabolism enzymes, proteins regulating cell motility, signaling proteins, and heat shock proteins, are discussed in terms of their metastasis.

Animals↗
PubMed2006

Rapid protein identification using monolithic enzymatic microreactor and LC-ESI-MS/MS.

A monolithic enzymatic microreactor was prepared in a fused-silica capillary by in situ polymerization of acrylamide, glycidyl methacrylate (GMA) and ethylene dimethacrylate (EDMA) in the presence of a binary porogenic mixture of dodecanol and cyclohexanol, followed by ammonia solution treatment, glutaraldehyde activation and trypsin modification. The choice of acrylamide as co-monomer was found useful to improve the efficiency of trypsin modification, thus, to increase the enzyme activity. The optimized microreactor offered very low back pressure, enabling the fast digestion of proteins flowing through the reactor. The performance of the monolithic microreactor was demonstrated with the digestion of cytochrome c at high flow rate. The digests were then characterized by CE and HPLC-MS/MS with the sequence coverage of 57.7%. The digestion efficiency was found over 230 times as high as that of the conventional method. In addition, for the first time, protein digestion carried out in a mixture of water and ACN was compared with the conventional aqueous reaction using MS/MS detection, and the former solution was found more compatible and more efficient for protein digestion.

Animals↗
PubMed2006

Acute and long-term effects of clinical doses of antenatal glucocorticoids in the developing fetal sheep kidney.

OBJECTIVES: The controversy regarding potential long-term side effects of antenatal steroid administration for accelerating fetal lung maturation is still unresolved despite more than 30 years of experience. Studies in animals have demonstrated that administration of glucocorticoids during pregnancy alters renal expression of several key regulatory molecules at different developmental stages followed in most cases with the development of hypertension in the adult. We studied the effects of betamethasone on the expression of (1) NA,K-ATPAse pump; (2) the Na/H exchanger 3 (NAHE3); (3) angiotensin receptor (AT1 and AT2); and (4) the type 1 dopamine receptor (D1R). METHODS: Pregnant sheep were treated with either 0.17 mg/kg betamethasone or vehicle 24 hours apart at 80 and 81 days' gestation. Fetal kidneys were harvested at 81 and 135 days' gestation. Protein and mRNA levels were measured in kidney cortex. RESULTS: Betamethasone had acute and long-term effects on fetal kidney cortex gene expression. Acutely, mRNA abundance for AT2 was significantly lower and that of NHE3 significantly higher than in controls (0.4 +/- 0.02 vs 0.7 +/- 0.05; 1.2 +/- 0.16 vs 0.4 +/- 0.04; P < .05). At 135 days' gestation, AT2 receptor abundance remained lower than control (0.2 +/- 0.02 vs 0.4 +/- 0.02; P < .05), whereas D1R expression was higher (0.8 +/- 0.17 vs 0.5 +/- 0.06; P < .05). No changes in Na,K-ATPase of AT1 receptor at either of the two time points studied were observed. Antenatal steroid administration was not associated with premature labor or a reduction in either body weight or kidney weight. CONCLUSION: Our findings strongly suggest that antenatal glucocorticoid administration according to National Institutes of Health (NIH) consensus guidelines may alter human fetal renal development. Further studies are needed to establish a direct relationship between alterations in fetal renal gene expression and the development of hypertension in adulthood.

Animals↗