ABSTRACT
The discovered giant clusters are always highly symmetric owing to the spontaneous assembly of one or two basic units. Herein we report the Gd44 Co28 crown and Gd95 Co60 cage, formulated as [Gd44 Co28 (IDA)20 (OH)72 (CO3 )12 (OAc)28 (H2 O)64 ]â (ClO4 )24 and [Na4 Gd95 Co60 (IDA)40 (OH)150 (CO3 )40 (OAc)58 (H2 O)164 ] â (ClO4 )41 (H2 IDA=iminodiacetic acid), respectively, by providing a library containing multiple low-nuclearity units. The heart-like units and crown-like tetramer found in both compounds indicate unprecedented assembly levels, leading to an atypical geometry characteristic compared to the giant clusters directly assembled by regular units. These two clusters not only significantly increase the size of Ln-Co clusters but also exhibit the enhanced magnetic entropy change at ultra-low temperatures. This work provided an effective way to fabricate cluster compounds with giant size and geometry complexity simultaneously.
ABSTRACT
The present paper describes the use of optical waveguide lightmode spectroscopy (OWLS) for study of the binding interaction of the vascular endothelial growth factor (VGEF) with VEGF receptor 2 (VEGFR2). VEGF were immobilized in the surface of an 3-amino 3-propyltriethoxy silane (APTES) modified sensor chip. The solutions with different concentration of VEGFR2 were injected to the system to investigate the kinetic character with OWLS on the solid and liquid interface. The receptor binding and dissociation on the interface, quantified by association and dissociation rate coefficients ka and kd, were determined by the OWLS experiments. The k(a) and k(d) is 6.86 x 10(5) L x mol(-1) x s(-1) and 1.15 x 10(-3) s(-1), respectively. The results show that OWLS method could meet the requirement of kinetic determination of ligand--receptor interaction in applications for related fundamental research and pharmaceutical development.
Subject(s)
Vascular Endothelial Growth Factor A/metabolism , Vascular Endothelial Growth Factor Receptor-2/metabolism , Kinetics , Ligands , Protein Binding , Spectrum AnalysisABSTRACT
Listeria monocytogenes (LM) is a food-borne pathogen inducing listeriosis, an illness characterized by encephalitis, septicaemia, and meningitis. Listeriolysin O (LLO) is absolutely required for virulence by L. monocytogenes, and is found only in virulent strains of the species. One of the best ways to detect and confirm the pathogen is detection of one of the virulence factors, LLO, produced by the microorganism. This paper focused on the electrical method used to detect the LLO toxin gene in food products and organism without labeling the target DNA. The electrochemical sensor was obtained by immobilizing single-stranded oligonucleotides onto the gold electrode with the mercaptan activated by N-hydroxysulfosuccinimide (NHS) and N-(3-dimethylamion)propyl-N'-ethyl carbodiimidehydrochloride (EDC). The hy-bridization reaction that occurred on the electrode surface was evidenced by Cyclic Voltammetry (CV) analysis using [Co(phen)3](ClO4)3 as an indicator. The covalently immobilized single-stranded DNA could selectively hybridize to its complementary DNA in solution to form double-stranded DNA on the gold surface. A significant increase of the peak cur-rent of Cyclic Voltammetry (CV) upon hybridization of immobilized ssDNA with PCR amplification products in the solu-tion was observed. This peak current change was used to monitor the amount of PCR amplification products. Factors deter-mining the sensitivity of the electrochemical assay, such as DNA target concentration and hybridization conditions, were investigated. The coupling of DNA to the electrochemical sensors has the potential of the quantitative evaluation of gene.
Subject(s)
Bacterial Toxins/analysis , Electrochemical Techniques/methods , Heat-Shock Proteins/analysis , Hemolysin Proteins/analysis , Bacterial Toxins/genetics , Biosensing Techniques/instrumentation , Biosensing Techniques/methods , Carbodiimides/chemistry , Cobalt/chemistry , DNA, Bacterial/chemistry , DNA, Bacterial/genetics , DNA, Single-Stranded/chemistry , DNA, Single-Stranded/genetics , Electrochemical Techniques/instrumentation , Electrodes , Gold/chemistry , Heat-Shock Proteins/genetics , Hemolysin Proteins/genetics , Humans , Listeria monocytogenes/genetics , Listeria monocytogenes/metabolism , Listeriosis/diagnosis , Listeriosis/microbiology , Organometallic Compounds/chemistry , Reproducibility of Results , Sensitivity and Specificity , Succinimides/chemistry , Sulfhydryl Compounds/chemistryABSTRACT
OBJECTIVE: To research the mechanism of the inhibition effects of BWE on cell attachment of influenza virus by capillary electrophoresis. METHOD: The morphologic difference of red cells after treating with BWE infected by influenza virus was detected with microscope, capillary electrophoresis and HA. RESULT: The pretreatment of the normal cells with BWE inhibited the attachment of influenza to the cells, while no meaningful inhibition was observed when influenza virus was pretreated before being inoculated to cells. CONCLUSION: The results indicate that the inhibition effects of BWE on cell attachment of influenza virus may be an important mechanism of anti-influenza activity of Radix Isatidis Extracts.
