Objective To express the beta hemolysin ( Hlb), an important toxin secreted by Staphylococcus aureus ( S.aureus) and the mutant protein Hlb H-149-N , to detect the hemolytic activity of Hlb and Hlb H-149-N on sheep erythrocytes , and to prepare the specific antibodies against Hlb which can inhibit the hemolytic activity of Hlb .Methods Hlb gene was amplified by PCR using S.aureus NCTC-8325 genome DNA as template.The expression vector pET-28a-hlb was constructed and transformed into E.coli BL21(DE3).The expression vector pET28a-hlbH-149-Nwas constructed through point mutation.The recombinant Hlb and Hlb H-149-N protein were expressed and purified by Ni 2+affinity chromatography .The hemolytic activity of Hlb and Hlb H-149-N was measured by sheep erythrocyte lysis assay .Results Recombinant Hlb protein and the mutant were obtained .Further investigations showed that Hlb could significantly induce the lysis of SRBC while HlbH-149-N could not.The specific polyclonal antibodies against Hlb (anti-Hlb) were prepared.It was found that anti-Hlb recognized Hlb and Hlb H-149-N .Moreover , it was found that anti-Hlb blocked the hemolytic activity of Hlb .Conclusion The recombinant Hlb protein with high hemolytic activity and Hlb H-149-N without hemolytic activity are obtained while its neutralized antibody is pepared .Hlb from S.aureus has different hemolytic effects on erythrocytes from various species .Our findings will facilitate the investigation on the role of Hlb in the pathogenesis of S.aureus.

Objective To clone and express alpha hemolysin ( Hla ) , one important virulence factor secreted by Staphylococcus aureus in Escherichia coli to tdetect the hemolytic activity of Hla on erythrocytes from diffrerent species ,and to prepare specific antibodies against Hla that can inhibit the hemolytic activity of Hla .Methods Hla gene was amplified by PCR using S.aureus NCTC-8325 genome DNA as a template.The expression vector pET-28a-Hla was constructed and transformed into E.coli BL21(DE3).The recombinant Hla protein was expressed by IPTG induction ,and then purified by Ni2+affinity chromatography .The hemolytic activity of Hla was measured by erythrocyte lysis assays .Results Soluble recombinant Hla protein was expressed and purified .Further investigations showed that Hla could significantly induce the lysis of rabbit erythrocytes .However , erythrocytes from humans or sheep were more resistant to the lysis mediated by Hla . The specific polyclonal antibodies against Hla ( anti-Hla) were prepared and detected by ELISA .Moreover, it was found that anti-Hla could inhibit the hemolytic activity of Hla .Conclusion We found that Hla from S.aureus has different hemolytic effects on erythrocytes from various species .The prepared Hla-antibodies can specifically block the hemolytic activity of Hla.

To study the chemical constituents of the inflorescences of Coreopsis tinctoria from Xinjiang, isolation and purification of constituents were carried out by column chromatography on macroporous resin (D101) , MCI gel, MDS gel, silica gel, Sephadex LH-20 and semi-preparative HPLC. The structures of the compounds were identified by physicchemical properties and spectral data analysis. Fourteen compounds were isolated and identified as coretinterpenoid A (1), coretinphenol (2), quercetin (3), quercetin-3-O-β-glucopyranoside (4), luteolin (5), taxifolin (6), 7, 3', 5'-trihydroxyflavanone (7), isookanin (8), isookanin-7-O-β-D-glucopyranoside (9), 5, 7, 3', 5'-tetrahydroxyflavanone-7-O-β-D-glucopyranoside (10), butein (11), okanin (12), sulfuretin (13), and linocinnamarin (14). Compound 1 was a new isabolane-type sesquiterpenoid and compounds 4, 10 and 13 were isolated from this plant for the first time.
Coreopsis ; chemistry ; Sesquiterpenes ; chemistry ; isolation & purification

OBJECTIVETo investigate the effect of rosiglitazone on the expression of nuclear factor-kappaB (NF-kappaB) and coupling factor 6 (CF6) induced by tumor necrosis factor-alpha (TNF-alpha) in cultured human umbilical vein endothelial cells (HUVEC).

METHODSCultured HUVEC of passage 3-5 were stimulated with TNF-alpha and then cultured in the presence of rosiglitazone. The expression of CF6 and NF-kappaB subunit p65 were evaluated by immunocytochemistical method.

RESULTSPretreatment of HUVECs with rosiglitazone inhibited TNF-alpha-induced expression of CF6 in a dose-dependent manner. The activation of CF6 stimulated by TNF-alpha was suppressed by ROS in a dose-dependent manner.

CONCLUSIONTNF-alpha-induced enhancement of the gene expression and release of CF6 is mediated by activation of NF-kappaB signaling pathway. ROS can inhibit the activation of IKK, block NF-kappaB signaling pathway and inhibit the expression of CF6, which may be the mechanism underlying the action of TZDs on hypertension.

Cells, Cultured ; Endothelial Cells ; cytology ; drug effects ; metabolism ; Humans ; Hypoglycemic Agents ; pharmacology ; Immunohistochemistry ; Mitochondrial Proton-Translocating ATPases ; biosynthesis ; NF-kappa B ; biosynthesis ; Oxidative Phosphorylation Coupling Factors ; biosynthesis ; Thiazolidinediones ; pharmacology ; Tumor Necrosis Factor-alpha ; pharmacology ; Umbilical Veins ; cytology

OBJECTIVETo investigate the effect of small interfering RNA (siRNA) targeting human vascular endothelial growth factor (hVEGF) on A549 cell growth in nude mice and angiogenesis on chorioallantoic membrane (CAM) assay.

METHODSThree pairs of hVEGF siRNA-plasmid and non-silencing-plasmid were constructed, and transfected into A549 cells through lipofectamine 2000, respectively. The most effective pair of hVEGF siRNA-plasmid was selected by ELISA and real-time RT-PCR. A549 cells transfected with selected hVEGF siRNA- plasmid, A549 cells transfected with non-silencing-plasmid and A549 cells without transfection were inoculated into nude mice, respectively. Chick embryos were randomly divided into four groups and CAM was treated by different solutions for 48 h: culture media DMEM as negative control group,un-transfected A549 cell culture supernatants as positive control group, hVEGF siRNA A549 cell culture supernatants as hVEGF siRNA group and nonsilencing siRNA A549 cell culture supernatants as non-silencing siRNA group. The CAMs were harvested on d12 for microscopic assays.

RESULTCompared with control group, hVEGF siRNA-plasmid induced 48% reduction in hVEGF secretion by A549 cells accompanied by 70% reduction in hVEGF mRNA. Compared with non-silencing siRNA group, the mean tumor volume of murine xenograft was reduced by 58% in hVEGF siRNA group; time for xenografts growing to 50 mm(3)was delayed by 5.4 d. hVEGF contents in xenograft were reduced by 54%; but mean doubling time of tumors and the growth rate of tumors were not significantly reduced. In CAM assays, hVEGF content was zero in negative group, and in hVEGF siRNA group that was 40%-44% of non-silencing siRNA group or positive group; vessels branch points of CAM in hVEGF siRNA group or non-silencing siRNA group or positive group were increased by 45%-55% compared with negative group; total vessel length of CAM in hVEGF siRNA group was increased by 53% compared with negative group, while in non-silencing siRNA group or positive group that was increased by 97% or 99%. Compared with negative control group, the proliferation of microvessels was increased when cell culture supernatant with hVEGF was added in hVEGF siRNA group, significant proliferated vessels were observed in non-silencing siRNA group or positive group.

CONCLUSIONA plasmid-mediated hVEGF siRNA has been constructed and verified, which can effectively downregulate the expression of hVEGF in human A549 cells, resulting in the inhibition of angiogenesis. hVEGF siRNA can delay initial growth of A549 tumor xenograft but not reduce the growth rate.

Adenocarcinoma ; pathology ; Animals ; Cell Line, Tumor ; Cell Proliferation ; Chick Embryo ; Chorioallantoic Membrane ; blood supply ; metabolism ; Female ; Humans ; Lung Neoplasms ; pathology ; Mice ; Mice, Inbred BALB C ; Mice, Nude ; Neoplasm Transplantation ; Neovascularization, Physiologic ; RNA Interference ; RNA, Messenger ; genetics ; RNA, Small Interfering ; genetics ; Vascular Endothelial Growth Factor A ; antagonists & inhibitors ; genetics

OBJECTIVETo investigate the effect of 5-fluorouracil (5-FU) on the expression of ATP-binding cassette superfamily G member 2 (ABCG2) in human colon cancer cell SW480.

METHODSSW480 cells were treated with various concentrations of 5-FU. CCK8 assay was utilized to detect the 5-FU IC50 to SW480 cells. Positive expression of ABCG2 was detected by flow cytometry, and mRNA expression of ABCG2 was detected by real time polymerase chain reaction (RT-PCR).

RESULTSThe 5-FU IC50 to SW480 cells increased as the drug concentration increased (P<0.05). Flow cytometry revealed that positive expression rate of ABCG2 in normal SW480 cells (group A) was (6.26±0.86)%. Immediately after treatment with 5-FU for 48 hours, the positive expression rate of ABCG2 (group B) was (3.43±1.18)% (P<0.05). In the second passage of cells after treatment with 5-FU for 48 hours, the positive expression rate of ABCG2 (group C) was (12.91±3.42)% (P<0.05). The mRNA expression of ABCG2 detected by RT-PCR was in accordance with the results from flow cytometry.

CONCLUSIONExpression of ABCG2 in SW480 cells can be affected by various concentrations of 5-FU.

ATP Binding Cassette Transporter, Sub-Family G, Member 2 ; ATP-Binding Cassette Transporters ; metabolism ; Cell Line, Tumor ; Colonic Neoplasms ; metabolism ; Fluorouracil ; pharmacology ; Humans ; Neoplasm Proteins ; metabolism

OBJECTIVETo optimize the solid-phase extraction method by comparison of the extraction recovery of ginsenoside Re plasma samples.

METHODAfter extracted by different solid-phase cartridges with water, acetonitrile, and different content methanol elution, the plasma samples were analyzed on an Zorbax SB-C18 column with acetonitrile-water gradient elution. From the recovery achieved, the best solid phase cartridge was found.

RESULTThis method consists of using 40% methanol as the wash solvent, and 80% methanol for the elution. Among the three kinds of solid-phase being tested, Waters Oasis HLB cartridge was found to be the best one.

CONCLUSIONThe average extraction recovery of the Waters Oasis HLB cartridges was between 103%-113%, it can be used in the analysis of ginsenoside Re in plasma samples.

Chromatography, High Pressure Liquid ; methods ; Ginsenosides ; blood ; isolation & purification ; Humans ; Panax ; chemistry ; Plants, Medicinal ; chemistry

OBJECTIVETo study the genetic association of apolipoprotein (apo) E and apoCI gene polymorphisms with coronary heart disease (CHD) in China.

METHODSapoE genotypes were identified by multiplex amplification refractory mutation system (multi-ARMS) and the apoCI promoter polymorphisms were detected by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) in 186 cases with CHD (age: 65.0 +/- 10.5 years) and 350 controls (age: 63.6 +/- 8.3 years). The haplotype frequencies were estimated.

RESULTSThe frequencies of apoE E4/3 genotype (26.9%) and epsilon4 (14.5%) in CHD group were significantly higher than that in the control group (12.6%, 7.0%), P <0.05. The significant difference was also found for the apoCI locus and the CHD group showed higher rate of both for the H2 allele and genotypes, carrying this allele. Estimation of the haplotype frequencies indicated that the association between the apoE-CI haplotype and CHD was significantly strong. The apoE-epsilon4/apoCI-H2 was estimated to be responsible for 9.86% of CHD.

CONCLUSIONWhen the subjects carrying both epsilon4 and H2 alleles, they would have higher risk of suffering from CHD than controls.

Adult ; Aged ; Aged, 80 and over ; Alleles ; Apolipoproteins C ; genetics ; Apolipoproteins E ; genetics ; China ; epidemiology ; Coronary Disease ; blood ; epidemiology ; genetics ; Female ; Genotype ; Haplotypes ; Humans ; Male ; Middle Aged ; Polymerase Chain Reaction ; Polymorphism, Restriction Fragment Length ; Risk Factors

Ascorbic Acid ; chemistry ; pharmacology ; Cellular Reprogramming ; Genetic Vectors ; genetics ; metabolism ; Histone Deacetylases ; genetics ; metabolism ; Humans ; Induced Pluripotent Stem Cells ; cytology ; drug effects ; Protein Kinase Inhibitors ; chemistry ; pharmacology ; RNA, Small Interfering ; metabolism

OBJECTIVE: To observe the inductive efficiency of deriving hematopoietic cells from human embryonic stem (hES) cells co-cultured with human yolk sac stromal cells, fetal liver stromal cells or fetal bone marrow stromal cells,in order to discuss the effect of the different hemopoietic microenvironment on hemopoietic cytogenesis. METHODS: We used two-step method to induce the hES cells into the hematopoietic cells. In the first step the hES cells were co-cultured with cytokines by formation of the day 5 embryoid bodies (5d EBs). In the second step the 5d EB cells were induced into the hematopoietic cells by co-culturing with human yolk sac stromal cells, fetal liver stromal cells or fetal bone marrow stromal cells for 10 days. The inductive efficiencies of deriving hematopoietic cells from hES cells co-cultured with the different hemopoietic microenvironment were reflected by the expression levels of flk, CD34 and CD45 antigen. RESULTS: Flow cytometry analysis demonstrated that the population of the cells co-cultured with human yolk sac stromal cells contained flk (1.80%+/-0.56%), CD34 (1.30%+/-0.14%) or CD45 (1.05%+/-0.63%) positive cells; the population of the cells co-cultured with human fetal liver stromal cells contained flk (34.00%+/-25.45%), CD34 (38.40%+/-24.80%) or CD45 (72.60%+/-25.70%) positive cells; the population of the cells co-cultured with human fetal bone marrow stromal cells contained flk (2.50%+/-1.48%), CD34 (3.20%+/-0.56%) or CD45 (1.65%+/-0.21%) positive cells. Compared with spontaneous differentiation of EBs, all of the three stromal cells could induce EBs into the hematopoietic cells (P<0.05). CONCLUSION The inductive efficiency of deriving hematopoietic cells from EBs co-cultured with human fetal liver stromal cells was higher than EBs co-cultured with human yolk sac stromal cells and fetal bone marrow stromal cells.
Antigens, CD34 ; Cell Differentiation ; Cells, Cultured ; Cellular Microenvironment ; Coculture Techniques ; Embryonic Stem Cells ; cytology ; Fetus ; cytology ; Hematopoietic Stem Cells ; cytology ; Humans ; Leukocyte Common Antigens ; Mesenchymal Stem Cells ; cytology ; Stromal Cells ; cytology ; Yolk Sac ; cytology