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2. Guanosine quadruplexes in solution : a small-angle X-ray scattering analysis of temperature effects on self-assembling of deoxyguanosine monophosphatePaolo Mariani, Francesco Spinozzi, Francesco Federiconi, M. G. Ortore, Heinz Amenitsch, Lea Spindler, Irena Drevenšek Olenik, 2010, izvirni znanstveni članek Opis: We investigated quadruplex formation in aqueous solutions of -deoxyriboguanosine -monophosphate, d(pG), which takes place in the absence of the covalent axial backbone. A series of in-solution small angle X-ray scattering experiments on d(pG) have been performed as a function of temperature in the absence of excess salt, at a concentration just above the critical one at which self-assembling occurs. A global fit approach has been used to derive composition and size distribution of the scattering particles as a function of temperature. The obtained results give thermodynamical justification for the observed phase-behavior, indicating that octamer formation is essential for quadruplex elongation. Our investigation shows that d(pG) quadruplexes are very suitable to assess the potential of G-quadruplex formation and to study the self-assembling thermodynamics.
Ključne besede: G-quadruplexes, guanosine
Objavljeno v DKUM: 14.06.2017; Ogledov: 916; Prenosov: 191
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3. Effect of base sequence on G-wire formation in solutionLea Spindler, Martin Rigler, Irena Drevenšek Olenik, Mateus Webba da Silva, Nason Ma'ani Hessari, 2010, izvirni znanstveni članek Opis: The formation and dimensions of G-wires by different short G-rich DNA sequences in solution were investigated by dynamic light scattering (DLS) and polyacrilamide gel electrophoresis (PAGE). To explore the basic principles of wire formation, we studied the effects of base sequence, method of preparation, temperature, and oligonucleotide concentration. Both DLS and PAGE show that thermal annealing induces much less macromolecular self-assembly than dialysis. The degree of assembly and consequently length of G-wires (5-6 nm) are well resolved by both methods for DNA sequences with intermediate length, while some discrepancies appear for the shortest and longest sequences. As expected, the longest DNA sequence gives the longest macromolecular aggregates with a length of about 11 nm as estimated by DLS. The quadruplex topologies show no concentration dependence in the investigated DNA concentration range (0.1 mM–0.4 mM) and no structural change upon heating.
Ključne besede: DNA, dynamic light scattering, DLS, polyacrylamide gel electrophoresis, PAGE, genetics
Objavljeno v DKUM: 14.06.2017; Ogledov: 1788; Prenosov: 373
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4. Effects of plasma treatment on water sorption in viscose fibresMiha Devetak, Nejc Skoporc, Martin Rigler, Zdenka Peršin Fratnik, Irena Drevenšek Olenik, Martin Čopič, Karin Stana-Kleinschek, 2012, izvirni znanstveni članek Opis: We investigated water sorption in viscose nonwoven fibres manufactured by Tosama d.d. with the surface density of 175 g/m2. A comparison between untreated fibres and by oxygen plasma treated fibres was made using optical polarization microscopy. Plasma treatment was done for 10 minutes at pressure of 75 Pa at current of 250 mA at the power of 500 W. Swelling was characterized by measurements of fibre diameter. Modifications of intensity of the polarized light transmitted through the fibre were measured as a function of time of exposure to water. Characteristic swelling and intensity modification times were resolved for untreated and oxygen plasma treated fibres. The swelling time of oxygen plasma in comparison to untreated plasma is reduced by the factor of 0.54 and intensity change time by the factor of 0.4. From the characteristic swelling and intensity change times it was concluded that oxygen plasma treatment of viscose increases the speed of water sorption.
Ključne besede: plasma treatment, viscose, optical polarization microscopy
Objavljeno v DKUM: 01.06.2012; Ogledov: 1972; Prenosov: 88
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