Search results for "Ligo"
showing 10 items of 1427 documents
Microvesicles shed by oligodendroglioma cells and rheumatoid synovial fibroblasts contain aggrecanase activity
2012
Membrane microvesicle shedding is an active process and occurs in viable cells with no signs of apoptosis or necrosis. We report here that microvesicles shed by oligodendroglioma cells contain an ‘aggrecanase’ activity, cleaving aggrecan at sites previously identified as targets for adamalysin metalloproteinases with disintegrin and thrombospondin domains (ADAMTSs). Degradation was inhibited by EDTA, the metalloproteinase inhibitor GM6001 and by tissue inhibitor of metalloproteinases (TIMP)-3, but not by TIMP-1 or TIMP-2. This inhibitor profile indicates that the shed microvesicles contain aggrecanolytic ADAMTS(s) or related TIMP-3-sensitive metalloproteinase(s). The oligodendroglioma cells…
Energy-Linked Reactions Catalyzed by the Purified ATPase Complex (F0F1) from Rhodospirillum rubrum Chromatophores
1980
1. The isolation of the F0F1-ATPase complex from Rhodospirillum rubrum chromatophores by the use of taurodeoxycholate is described. 2. The enzyme preparation contains about 12 polypeptides; five are subunits of the F1 moiety. 3. The ATPase activity of the purified enzyme is dependent on the addition of phospholipids. 4. Km-vales for Mg2+-ATP and Ca2+-ATP are similar to the values obtained for the membrane-bound enzyme. 5. The F0F1-ATPase complex is more than 70% inhibited by oligomycin and N,N′-dicyclohexyl-carbodiimide. 6. The F0F1-ATPase complex was integrated into liposomes. The reconstituted proteoliposomes catalyzed energy transduction as shown by ATP-dependent quenching of acridine dy…
Pump and Displacement Currents of Reconstituted ATP Synthase on Black Lipid Membranes
1988
Purified ATP synthase (F0F1) from Rhodospirillum rubrum was reconstituted into asolectine liposomes which were then adsorbed to a planar lipid bilayer. After the addition of an inactive photolabile ATP derivative (caged ATP), ATP was released after illumination with u.v.-light, which led to a transient current in the system. The transient photocurrent indicates that the vesicles and the planar membrane are capacitatively coupled. Stationary pump currents were obtained after addition of protonophores. These currents are specifically inhibited by oligomycin and stimulated threefold by inorganic phosphate (Pi). In analogy oligomycin sensitive pump currents in the reverse direction coupled to n…
Nanomaterial-based cocaine aptasensors.
2015
Up to now, many different methods have been developed for detection of cocaine, but most of these methods are usually time-consuming, tedious and require special or expensive equipment. Therefore, the development of simple, sensitive and rapid detection methods is necessary. In the last decade, aptamers have been used as a new biosensor platform for detection of cocaine in different samples. Aptamers are artificial single-stranded DNA or RNA oligonucleotides capable of binding to specific molecular targets with high affinity and if integrated to nanomaterials, it may lead in precise methods for cocaine detection in the common laboratories. In this review, recent advances and applications of…
Modeling hole transfer in DNA: Low-lying excited states of oxidized cytosine homodimer and cytosine–adenine heterodimer
2008
Abstract Charge transport in DNA strands has been studied by characterizing on theoretical grounds the lowest doublet states of the oxidized cytosine homodimer (CC + ) and adenine–cytosine heterodimer (CA + ) along the intermolecular separation of the monomers. The high-level quantum-chemical ab initio CASPT2 method and accurate one-electron basis sets have been employed. Both cationic species are found to be bound with comparable binding energies as those of neutral CC and reduced CC − . The results suggest that charge transport in DNA and the distinct photophysical attributes related to the polymer can be described within the framework of a unified theory. A cooperative micro-hopping mech…
Mechanical and electroconductive properties of spatially distributed double stranded DNA arrays on Au (111)
2008
Abstract Conductive AFM was used to investigate electroconductivity through 10 nm long double stranded DNA molecules in mixed monolayers of thioalkylated-DNA and mercaptohexanol (MCH) on Au (111) surface. The distribution of DNA molecules on the surface was analyzed by tapping mode AFM. Measurements performed in lift mode confirmed that the DNA molecules protrude from the surface rather than lie horizontally adsorbed on the interface. The optimal conductivity measurement time, which is shorter than the mechanical relaxation time of oligonucleotide duplexes, was determined. It was concluded that oligonucleotide duplexes have a resistance of the order of ~ 2 Ω ⁎ m at 1 V.
Functional Studies of Regulatory Genes in the Sea Urchin Embryo
2008
Sea urchin embryos are characterized by an extremely simple mode of development, rapid cleavage, high transparency, and well-defined cell lineage. Although they are not suitable for genetic studies, other approaches are successfully used to unravel mechanisms and molecules involved in cell fate specification and morphogenesis. Microinjection is the elective method to study gene function in sea urchin embryos. It is used to deliver precise amounts of DNA, RNA, oligonucleotides, peptides, or antibodies into the eggs or even into blastomeres. Here we describe microinjection as it is currently applied in our laboratory and show how it has been used in gene perturbation analyses and dissection o…
Sample pretreatment techniques for oligopeptide analysis from natural sources
2008
The analysis of oligopeptides in samples of food, tissues, and body fluids attracts considerable attention. The complexity of such samples requires efficient sample preparation (i.e., concentration and cleanup) procedures to remove interfering endogenous compounds and inorganic or organic salts. The methods of sample pretreatment that enable effective and selective isolation and/or preconcentration of oligopeptides from complex sample matrices have been reviewed. In each case, examples of application were presented and discussed, taking into account selectivity, enrichment, method automation, cleanup, and environmental aspects of the developed methods.
Synthesis of the new oligopeptide pyrrole derivative isonetropsin and its one pyrrole unit analogue
2013
We have designed and synthesized isonetropsin and its one pyrrole unit analogue in which the amine and carbonyl groups have been switched in positions 2 and 4, respectively instead of 4 and 2 positions of the natural antibiotic netropsin.
Asymmetric Demand Information and Foreign Direct Investment
2007
We examine the FDI versus exports decision of firms competing in an oligopolistic (quantitysetting) market under demand uncertainty and asymmetric information. Compared to a firm that chooses to export, a firm that chooses to set up a plant in the host market has superior information about local market demand. In addition to the well-known tension between the fixed set-up costs of investment, the additional variable costs of exports and oligopoly sizes, the incentive to invest abroad is explained by the strategic learning effect. FDI may be observed even if trade costs are zero. The analysis is robust to price competition and to the possibility that a foreign firm can engage in both FDI and…