ABSTRACT
Based on melamine-Cu conjugate and subsequent interruption of formation of polythymine (Poly T)-templated copper nanoclusters (CuNCs), a novel fluorescent strategy was developed for detection of melamine.The method relied on the principle that the coordination of melamine to copper would be unfavorable for the reduction of Cu2+ in the poly T-CuNCs synthesis process, and thereby resulting in the decrease of fluorescence intensity of CuNCs.By this method, the fluorescence response of CuNCs displayed an linear relationship with melamine concentration in the range from 5 μmol/L to 120 μmol/L.The detection limit was 1.5 μmol/L.Furthermore, the assay was successfully applied in the detection of melamine in milk samples with good recoveries.
ABSTRACT
Objective:To improve the immunoblotting of immunoprecipitated proteins and decrease the interference of immunoprecipitation antibody in the interaction of endogenous proteins. Methods:Transient transfect cells with fusion protein expression vector containing the targeted S5b gene and the FLAG tag, the transfected cells or untransfected cells were harvested to study the exogenous or endogenous protein interaction. The total cell lysate was immunoprecipitated by specific antibody. Then the eluted immunocomplex was separated by SDS-PAGE, and the TrueBlot antibody or conventional antibody was used as the secondary antibody for immunoblotting detection of S5b and its partner (Rpt1 and Rpt2). Results:Clear immunoblotting bands for S5b, Rpt1 and Rpt2 were obtained. Conclusion:TrueBlot antibody prefers the immunoblot antibody to immunoprecipitation antibody, and decreases the interruption of immunoprecipitation antibody to display clear protein band.
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Objective To establish a new non radioimmunoassay for detecting insulin. Methods We put together the techniques of chemiluminescent analysis, flow injection analysis and immunoassay and established a method,flow injection chemiluminescent immunoassay, for insulin determination using sandwhich procedure with the horseradish peroxdase (HRP) as label of antibody and using the detection system of synergistic enhanced chemiluminescence of para phenylpenol and sodium tetraphenylborate with HRP catalysed oxidation of luminol. Results Satisfactory results were obtained in the dynamic range 0.15～60.00 ?U with a relative coefficient of 0 997 2 ( P
ABSTRACT
Objective To construct the double-H1promoters siRNA expression cassettes(SECs) targeted to human telomere retrotranscriptase(hTERT),and investigate the interfering effect of its siRNA on hTERT gene expression in HepG2 cells.Methods SECs were constructed by fusing PCR,based on two different human telomerase hTERT gene fragments.When SEGs transferred into HepG2 cells respectively,the SECs were transcripted to the siRNA.The interfering effect of SECs on the telomerase activity in the cells was assessed by telomeric repeat amplification protocol(TRAP) and PCR-EIA.Results SEGs were successful constracted,and the telomerase activity was significantly inhibited when the HepG2 cells were tranfected with SECs.Conclusions The siRNA SECs display a definite RNA interference effect on the expression of telomerase.This method of SECs preparation can be applied for RNAi research in tumor inhibition.
ABSTRACT
Objective To apply a fluorescent nucleotide dye Sybr Green I in detecting telomerase activity and assess its clinical value in the diagnosis of colorectal carcinoma. Methods Telomerase activity was (measured) by telomeric repeat amplification protocol (TRAP) combined with fluorescent nucleotide dye Sybr Green I in 46 cases of colorectal carcinoma tissue specimens and 19 tumor-adjacent tissue (specimens). Results (Telomeric) repeat amplification product was displayed as clear bands in PAGE stained with Sybr Green I; the positive rate of telomoerase activity in colorectal carcinoma tissue was 89.13%, whereas no telomerase (activity) was observed in 19 tumor-adjacent tissue specimens. There was no (relationship) between telomerase (activity) and the level of cell differentiation, Dukes stages, or metastasis of lymph nodes. Conclusions The method of TRAP combined with Sybr Green I to determine telemerase (activity) is an important method for the diagnosis of colorectal carcinoma.