|
| ||
|
|
||
CT DNA (ct + dna)
Selected AbstractsEffects of inflammatory response on in vivo transgene expression by plasmid DNA in miceJOURNAL OF PHARMACEUTICAL SCIENCES, Issue 8 2008Keiko Kako Abstract To examine the effects of inflammatory response to plasmid DNA (pDNA) on transgene expression, serum tumor necrosis factor-, (TNF-,) was measured after intravenous injection of pDNA or calf thymus DNA (CT DNA) in the naked or complexed form with cationic liposomes (lipoplex). pDNA with many CpG motifs induced TNF-, production regardless of the forms. No significant TNF-, production was detected when CT DNA or methylated pDNA was injected. Clodronate liposomes and dexamethasone were used to deplete phagocytes or to inhibit inflammatory responses, respectively. Transient depletion of phagocytes, such as liver Kupffer cells and splenic macrophages, by clodronate liposomes slightly altered the tissue distribution of 32P-pDNA lipoplex, but significantly reduced the TNF-, production and transgene expression. Dexamethasone significantly inhibited the initial transgene expression, but increased the duration of the expression slightly. Use of NF-,B activity-dependent plasmid vector suggested that the inhibition of NF-,B activation is involved in the reduced expression by these treatments. These findings indicate that tissue macrophages are closely involved in the CpG motif-dependent TNF-, production. It is also suggested that TNF-, activates NF-,B and increases transgene expression by pDNA having many NF-,B binding sites, but TNF-, also reduces transgene expression at later time periods, leading to short-term transgene expression. © 2007 Wiley-Liss, Inc. and the American Pharmacists Association J Pharm Sci 97: 3074,3083, 2008 [source] A solid-state 23Na NMR study of monovalent cation binding to double-stranded DNA at low relative humidityMAGNETIC RESONANCE IN CHEMISTRY, Issue 4 2008Alan Wong Abstract We report a solid-state 23Na NMR study of monovalent cation (Li+, Na+, K+, Rb+, Cs+ and NH4+) binding to double-stranded calf thymus DNA (CT DNA) at low relative humidity, ca 0,10%. Results from 23Na31P rotational echo double resonance (REDOR) NMR experiments firmly establish that, at low relative humidity, monovalent cations are directly bound to the phosphate group of CT DNA and are partially dehydrated. On the basis of solid-state 23Na NMR titration experiments, we obtain quantitative thermodynamic parameters concerning the cation-binding affinity for the phosphate group of CT DNA. The free energy difference (,G° ) between M+ and Na+ ions is as follows: Li+ (,1.0 kcal mol,1), K+ (7.2 kcal mol,1), NH4+ (1.0 kcal mol,1), Rb+ (4.5 kcal mol,1) and Cs+ (1.5 kcal mol,1). These results suggest that, at low relative humidity, the binding affinity of monovalent cations for the phosphate group of CT DNA follows the order: Li+ > Na+ > NH4+ > Cs+ > Rb+ > K+. This sequence is drastically different from that observed for CT DNA in solution. This discrepancy is attributed to the different modes of cation binding in dry and wet states of DNA. In the wet state of DNA, cations are fully hydrated. Our results suggest that the free energy balance between direct cation,phosphate contact and dehydration interactions is important. The reported experimental results on relative ion-binding affinity for the DNA backbone may be used for testing theoretical treatment of cation-phosphate interactions in DNA. Copyright © 2008 John Wiley & Sons, Ltd. [source] Sequence-dependent Interactions of Cationic Naphthalimides and PolynucleotidesPHOTOCHEMISTRY & PHOTOBIOLOGY, Issue 4 2007Sun McMasters The binding interactions of three naphthalimide derivatives with heteropoly nucleic acids have been evaluated using fluorescence, absorption and circular dichroism spectroscopies. Mono- and bifunctionalized naphthalimides exhibit sequence-dependent variations in their affinity toward DNA. The heteropoly nucleic acids, [Poly(dA-dT)]2 and [Poly(dG-dC)]2, as well as calf thymus (CT) DNA, were used to understand the factors that govern binding strength and selectivity. Sequence selectivity was addressed by determining the binding constants as a function of polynucleotide composition according to the noncooperative McGhee,von Hippel binding model. Binding affinities toward [poly(dA-dT)]2 were the largest for spermine-substituted naphthalimides (Kb = 2,6 × 106 m,1). The association constants for complex formation between the cationic naphthalmides and [poly(dG-dC)]2 or CT DNA (58% A-T content) were 2,500 times smaller, depending on the naphthalmide,polynucleotide pair. The binding modes were also assessed using a combination of induced circular dichroism and salt effects to determine whether the naphthalimides associate with DNA through intercalative, electrostatic or groove-binding. The results show that the monofunctionalized spermine and pyridinium-substituted naphthalimides associate with DNA through electrostatic interactions. In contrast, intercalative interactions are predominant in the complex formed between the bifunctionalized spermine compound and all of the polynucleotides. [source] Effect of Electronic Structures of Enantiomers of Ruthenium(II) Polypyridyl Complexes on DNA Binding BehaviorsCHINESE JOURNAL OF CHEMISTRY, Issue 8 2010Haimei Luo Abstract A pair of Ru(II) complex enantiomers, , - and , -[Ru(bpy)2(p -mpip)]2+ {bpy=2,2,-bipyridine, p -mpip=2-(4-methylphenyl)imidazo[4,5-f]-1,10-phenanthroline} have been synthesized and structurally characterized. Both experimental results from crystallography, NMR, electrochemistry and theoretical calculations applying the density functional theory (DFT) method based on their crystal structures show that small difference in geometric structure existed can cause a considerable difference in electronic structure between enantiomers. In addition, the binding of the two enantiomers to calf thymus DNA (CT DNA) has been investigated with UV spectroscopy titration and viscosity measurements. It is very rare that the , enantiomer binds to DNA more strongly than the , enantiomer, which can be reasonably explained by their different electronic structures for the first time, suggesting that the dominant factor governing the stereoselectivity of DNA binding of Ru(II) complex may be the different electronic structures of its enantiomers. [source] Determination of nucleic acid by [tetra-(3-methoxy-4-hydroxyphenyl)],Tb3+ porphyrin as the fluorescence spectral probe in bis(2-ethylhexyl)sulfosuccinate sodium salt micelle systemLUMINESCENCE: THE JOURNAL OF BIOLOGICAL AND CHEMICAL LUMINESCENCE, Issue 4 2009Xin Chen Abstract A new system for the determination of nucleic acid by rare earth metallic porphyrin of [tetra-(3-methoxy-4-hydroxyphenyl)],Tb3+ [T(3-MO-4HP),Tb3+] porphyrin as fluorescence spectral probe has been developed in this paper. Nucleic acid can enhance the fluorescence intensity of the T(3-MO-4HP),Tb3+ porphyrin in the presence of bis(2-ethylhexyl)sulfosuccinate sodium salt(AOT) micelle. In pH 8.00 Tris,HCl buffer solution, under optimum conditions, the enhanced fluorescence intensity is in proportion to the concentration of nucleic acids in the range of 0.05,3.00 µg mL,1 for calf thymus DNA (ct DNA) and 0.03,4.80 µg mL,1 for fish sperm DNA(fs DNA). Their detection limits are 0.03 and 0.01 µg mL,1, respectively. In addition, the binding interaction mechanism between T(3-MO-4HP),Tb3+ porphyrin and ct DNA is also investigated by resonance scattering and fluorescence spectra. The maximum binding number is calculated by molar ratio method. The new system can be used for the determination of nucleic acid in pig liver, yielding satisfactory results. Copyright © 2009 John Wiley & Sons, Ltd. [source] Resonance Light Scattering Imaging Detection of Single Suprahelical Species of DNA Induced by Porphine-5,10,15,20-tetrakis(p -phenyltrimethylaminium)CHINESE JOURNAL OF CHEMISTRY, Issue 1 2006Xi-Dong Liu Abstract A resonance light scattering (RLS) imaging method was proposed based on imaging and measuring the RLS features of single suprahelical species of DNA, and its application to DNA assay was also investigated. In acidic medium, porphine-5,10,15,20-tetrakis(p -phenyltrimethylaminium) (PTPTMA), could stack along the molecular surface of DNA with the mode of long-range assembly to induce the formation of suprahelical species of DNA, resulting in strong RLS signals in the range of 450,510 nm. Under the excitation of 488 nm light beam of argon ion laser source, single suprahelical species could be observed with the aid of a common microscope due to the strong scattered light emitted by the suprahelical species. By capturing the RLS images of the single suprahelical species with a cooled charge coupled device (CCD) camera, and analyzing the RLS data, herein an RLS imaging method of DNA was proposed based on the linear relationship between the counts of suprahelical species in the detection focus plane and the concentration of DNA in nanograms. When 1.8??µmol/L PTPTMA was employed, both calf thymus DNA (ct DNA) and fish sperm DNA (fs DNA) in the range of 25,1100 ng/mL could be detected with the limits of detection lower than 25 ng/mL (3,). Four synthetic samples were detected satisfactorily with relative standard deviations less than 5.1%. [source] | ||||||||||