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891.
The intranuclear disposition of a plasmid is extremely important for transgene expression. The effects of a left-handedly curved sequence with high histone affinity on plasmid expression were examined in vivo. A naked luciferase-plasmid was delivered into mouse liver by a hydrodynamics-based injection, and the luciferase activities were quantitated at various time points. The location of the left-handedly curved sequence determined the transgene expression, without affecting the amount of intranuclear exogenous DNA. The plasmid containing the curved sequence at the location that results in the exposure of the TATA box out of the nucleosome core showed the highest expression. These results suggest that sequences with high histone affinity could control transgene expression from plasmids in vivo. 相似文献
892.
An amperometric l-lactate biosensor was fabricated by confining lactate oxidase in a Prussian Blue-modified electrode with a Nafion membrane. The detector was assembled in a flow injection apparatus and operated at -0.1 V. Conditions for optimal electrode response were determined by investigating the influence of the amount of immobilized enzyme, the sample volume, and the flow rate. At the established operational conditions, the biosensor exhibited negligible response from interfering species usually present in biological fluids. The stability of the biosensor was also investigated, and its sensitivity was maintained unchanged at certain experimental conditions. l-Lactate was determined in blood samples, and the influence of physical exercise on the results was clearly evidenced, demonstrating that the proposed amperometric detector is suitable for monitoring changes in the l-lactate levels in biological fluids. 相似文献
893.
894.
895.
Zhouping Wang Huan Xu Jia Qian Jing Ye Zhen Yang Huachao Sun Yonghui Shi 《Luminescence》2010,25(4):300-306
In the present work, a simple chemiluminescence (CL) method coupled with flow‐injection analysis for the evaluation of antioxidant activity of 5′‐nucleotides (5′‐AMP, 5′‐CMP, 5′‐GMP, 5′‐UMP) was proposed. It is based on inhibition effect of the studied substances on CL emission of luminol–potassium ferricyanide–pyrogallol. Experiments were performed to evaluate the nature of the inhibition by 5′‐nucleotides of the CL reaction and their antioxidant activities. Based on the experimental results, it was observed that 5′‐nucleotides are available antioxidants that could effectively scavenge superoxide anion free radicals in a concentration‐dependent way. This will provide a basis for further development of the use of nucleotides. Copyright © 2009 John Wiley & Sons, Ltd. 相似文献
896.
A simple and green flow injection chemiluminescence (FI‐CL) method for determination of the fungicide azoxystrobin was described for the first time. CL signal was generated when azoxystrobin was injected into a mixed stream of luminol and KMnO4. The CL signal of azoxystrobin could be greatly improved when an off‐line ultrasonic treatment was adopted. Meanwhile, the signal intensity increases with the analyte concentration proportionally. Several variables, such as the ultrasonic parameters, flow rate of reagents, concentrations of sodium hydroxide solution and CL reagents (potassium permanganate, luminol) were investigated, and the optimal CL conditions were obtained. Under optimal conditions, the linear range of 1–100 ng/mL for azoxystrobin was obtained and the detection limit (3σ) was determined as 0.13 ng/mL. The relative standard deviation was 1.5% for 10 consecutive measurements of 20 ng/mL azoxystrobin. The method has been applied to the determination of azoxystrobin residues in water samples. Copyright © 2012 John Wiley & Sons, Ltd. 相似文献
897.
Five mutants of Lactococcus lactis subsp. cremoris 3107 resistant to phage TP901-1 were obtained after treatment with ethyl methanesulfonate. Two of the mutants were also resistant to phage phiLC3. The remaining three mutants were as sensitive as 3107. Mutants E46 and E100 did not adsorb the two phages. Mutants E119, E121 and E126 adsorbed phage phiLC3 as well as 3107 but phage TP901-1 with significantly reduced efficiency. All, except E46, could be lysogenized with phage TP901-BC1034, a derivative of TP901-1 harboring an erythromycin-resistance marker. However, the lysogenization frequency was 10(3)-10(4) fold higher for 3107 than for the mutants. Mitomycin C induction of lysogenized mutants 3107 indicated that phage propagation was not affected in these four mutants. Electron microscopy and analysis of total DNA of infected cells showed that DNA was liberated from the phage particle during infection of strain 3107 with TP901-1 and that intracellular phage DNA replication occurred. This was not the case for mutants E121 and E126. This strongly suggests that some step starting with triggering DNA release and ending with DNA injection is impaired during infection with TP901-1. As such impairment was not seen when infecting E119, E121 and E126 with phiLC3, we conclude that TP901-1 and phiLC3 either are differently triggered by their receptor or utilize different pathways of injection. 相似文献
898.
Production of transgenic mice carrying the Thanatin gene by intratesticular injection 总被引:1,自引:0,他引:1
Transgenic animals have potential applications in medicine, life sciences, and biopharmacy. In this study, we developed a convenient, economic, and efficient method for gene transfer by transfection of male spermatogonial stem cells. Three fragments of the Thanatin gene, encoding an antibacterial peptide, were synthesized and amplified by overlap extension polymerase chain reaction (PCR). They were inserted into vector pIRES2-EGFP. The pIRES2-EGFP-Thanatin plasmid was mixed with liposomes and injected into the testes of male mice by a minimally invasive operation. Six weeks after injection, male mice were mated with normal female mice to produce an F1 generation. PCR and Southern blotting were performed to analyze F1 mice. Among those 52 F1 mice produced, 38.46% were found to be positive for the Thanatin gene by PCR and 30.77% by Southern blotting. Six positive mice were selected from the F1 generation and mated with normal females to an F2 generation, in which 36.36% were found to be positive for the Thanatin gene. Expression of the green fluorescence protein in the transgenic mice was confirmed by fluorescence imaging. These results showed that the Thanatin gene was integrated into the mouse genome. The study provides a useful method for the future development of disease-resistant animals and production of antibacterial peptides through transgenic animals. 相似文献
899.
900.
A review of the literature on unusual metals as carcinogens was carried out. The metals covered are some of the rare earths,
copper, silver, gold, mercury, germanium, tin, antimony, lead, platinum, palladium, aluminum, titanium, niobium, manganese,
scandium, yttrium, indium, rhodium, and gallium. 相似文献