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Separation of nonpolar lipids from vernix caseosa
Háková, Eva; Míková, Radka; Vrkoslav, Vladimír; Doležal, A.; Plavka, R.; Cvačka, Josef
2014 - English
The aim of this work is to develop a separation method for characterization of unknown nonpolar lipids in vernix caseosa. Here we optimized adsorption chromatography coupled to mass spectrometry detection with exact mass measurement. A long silica gel column (250 + 250 x 4.6 mm, particle size: 5 mu m) provided the best separation of nonpolar lipids present in vernix caseosa.
Keywords:
vernix caseosa; lipids; normal-phase chromatography; mass spectrometry
Available at various institutes of the ASCR
Separation of nonpolar lipids from vernix caseosa
The aim of this work is to develop a separation method for characterization of unknown nonpolar lipids in vernix caseosa. Here we optimized adsorption chromatography coupled to mass spectrometry ...
Capillary electrophoresis applied to chiral analysis of helquats and characterization of their intermediates and interconversion barriers using randomly and single isomer sulfated cyclodextrins as stereoselectors
Kašička, Václav; Koval, Dušan; Sázelová, Petra; Severa, Lukáš; Vávra, Jan; Adriaenssens, Louis; Sonawane, Manoj R.; Teplý, Filip
2014 - English
Capillary electrophoresis in acidic sodium phosphate background electrolyte, pH 2.4, with randomly sulfated alfa-, beta- and gamma-cyclodextrins as chiral selectors was applied to fast, high-resolution separation of enantiomers of a series of 35 helquats, a new class of N-heteroaromatic dicationic helicene-like species. The developed methodology was employed for evaluation of preparative enantioresolution procedures of helquats, for monitoring their racemization and for determination of interconversion barrier of helquat enantiomers.
Keywords:
helquats; chiral analysis; capillary electrophoresis
Available at various institutes of the ASCR
Capillary electrophoresis applied to chiral analysis of helquats and characterization of their intermediates and interconversion barriers using randomly and single isomer sulfated cyclodextrins as stereoselectors
Capillary electrophoresis in acidic sodium phosphate background electrolyte, pH 2.4, with randomly sulfated alfa-, beta- and gamma-cyclodextrins as chiral selectors was applied to fast, ...
Affinity capillary electrophoresis applied for study of solvent effect on stability constant of dibenzo-18-crown-6 complex with potassium ion
Konášová, Renáta; Jaklová Dytrtová, Jana; Kašička, Václav
2014 - English
Affinity capillary electrophoresis was used for investigation of solvent effect on stability constant of dibenzo-18-crown-6 complex with potassium ion in mixed hydro-organic solvents at different water/methanol and water/ethanol ratios. The stability constant of the complex was decreasing with increasing molar fraction of water in mixed solvents and almost independent of the organic solvent used.
Keywords:
affinity capillary electrophoresis; solvent effect; binding constant
Available at various institutes of the ASCR
Affinity capillary electrophoresis applied for study of solvent effect on stability constant of dibenzo-18-crown-6 complex with potassium ion
Affinity capillary electrophoresis was used for investigation of solvent effect on stability constant of dibenzo-18-crown-6 complex with potassium ion in mixed hydro-organic solvents at different ...
Switchable intramolecular hydrogen bond in polysubstituted 5-nitrosopyrimidines
Procházková, Eliška; Čechová, Lucie; Žurek, Jiří; Janeba, Zlatko; Dračínský, Martin
2014 - English
The formation of strong intramolecular hydrogen bonds was observed in a series of 2-amino-5-nitrosopyrimidines with alkylamino and arylamino substituents in the positions 4 and 6. Mixtures of two rotamers differing in the orientation of the nitroso group were observed in the NMR spectra of the compounds where two distinct intramolecular hydrogen bonds could be formed. In several cases, we were able to isolate and characterize the two hydrogen bond isomers (two conformers) by column chromatography. The ratio of the two rotamers in equilibrium depends strongly on the character of the substituents in the positions 4 and 6 and can be finely tuned in a broad range of conformation ratios. The experimental results were supported by DFT calculations.
Keywords:
intramolecular hydrogen bonds; polysubstituted 5-nitrosopyrimidines; NMR spectroscopy
Available at various institutes of the ASCR
Switchable intramolecular hydrogen bond in polysubstituted 5-nitrosopyrimidines
The formation of strong intramolecular hydrogen bonds was observed in a series of 2-amino-5-nitrosopyrimidines with alkylamino and arylamino substituents in the positions 4 and 6. Mixtures of two ...
5-(Pyren-1-yl)uracil UNA monomers: Synthesis, hybridization studies and i-motif stability
Perlíková, Pavla; Pedersen, E. B.; Wengel, J.
2014 - English
We have used direct conjugation of a pyrene moiety to a uracil base in synthesis of novel pyrene-modified UNA building blocks. Oligonucleotides with bulge-incorporated pyrene-modified UNA monomers showed increased duplex thermal stability, whereas destabilizing effect was observed in fully matched duplexes and in i-motifs.
Keywords:
5-(pyren-1-yl)uracil UNA monomers; DNA; unlocked nucleic acids
Available at various institutes of the ASCR
5-(Pyren-1-yl)uracil UNA monomers: Synthesis, hybridization studies and i-motif stability
We have used direct conjugation of a pyrene moiety to a uracil base in synthesis of novel pyrene-modified UNA building blocks. Oligonucleotides with bulge-incorporated pyrene-modified UNA monomers ...
Insights into the mechanism of action of bactericidal lipophosphonoxins
Panova, Natalya; Zborníková, Eva; Šimák, Ondřej; Krásný, Libor; Kolář, M.; Látal, T.; Seydlová, G.; Rejman, Dominik
2014 - English
The advantages offered by antibiotics in the treatment of infectious diseases are endangered due to the increase in the number of antibiotic-resistant bacterial strains. This reduces the efficiency of antibiotic treatments and poses a serious health and economical problem. Currently, the need for novel antibiotics is becoming increasingly apparent. Recently, we discovered a series of compounds termed lipophosphonoxins exhibiting selective cytotoxicity towards gram-positive bacterial cells. The attempt to elucidate the mode of action of lipophosphonoxins is presented here.
Keywords:
lipophosphonoxins; cytotoxicity; antibiotics
Available at various institutes of the ASCR
Insights into the mechanism of action of bactericidal lipophosphonoxins
The advantages offered by antibiotics in the treatment of infectious diseases are endangered due to the increase in the number of antibiotic-resistant bacterial strains. This reduces the efficiency ...
Tyrosine-based prodrugs of acyclic nucleoside phosphonates
Tichý, Tomáš; Pomeisl, Karel; Krečmerová, Marcela; McKenna, Ch. E.
2014 - English
Prodrug approach based on masking of a phosphonate function by ester linkage to a tyrosine promoiety has been developed. Results demonstrate that tyrosine is a promoiety providing drug conjugates with good chemical stability, bioavailability and efficient activation to active drug species. Another properties like metabolic stability and antiviral activity can be tuned by modification of the carboxyl function of the promoiety. Phosphonate monoester prodrugs were prepared by PyBOP coupling of a protected tyrosine promoiety with suitably derivatized phosphonate function of the parent drug. Phosphonate diester prodrugs were prepared by "synthon" approach, emloying alkylation of purine nucleobase with pre-prepared PME synthons bearing two protected tyrosine promoieties.
Keywords:
acyclic nucleoside phosphonates; prodrug; tyrosine
Available at various institutes of the ASCR
Tyrosine-based prodrugs of acyclic nucleoside phosphonates
Prodrug approach based on masking of a phosphonate function by ester linkage to a tyrosine promoiety has been developed. Results demonstrate that tyrosine is a promoiety providing drug conjugates ...
Redox labeling and redox coding of nucleic acids
Balintová, Jana; Brázdová, Marie; Havran, Luděk; Fojta, Miroslav; Hocek, Michal
2014 - English
Modified nucleoside triphosphates (dNTPs) bearing benzofurazane, azides and triazoles were prepared by Sonogashira or Suzuki cross-coupling. Polymerase incorporations of the functionalyzed dNTPs into DNA by primer extension and their electrochemical properties have been studied.
Keywords:
nucleic acids; DNA; dNTPs
Available at various institutes of the ASCR
Redox labeling and redox coding of nucleic acids
Modified nucleoside triphosphates (dNTPs) bearing benzofurazane, azides and triazoles were prepared by Sonogashira or Suzuki cross-coupling. Polymerase incorporations of the functionalyzed dNTPs into ...
Study of DNA-protein interactions by cross-link formation using aqueous Michael addition
Daďová, Jitka; Orság, Petr; Pohl, Radek; Brázdová, Marie; Fojta, Miroslav; Hocek, Michal
2014 - English
Acrylamide and vinylsulfonamide were designed as reactive DNA modifications for covalent crosslinking with cysteine containing peptides and proteins. The corresponding functionalized cytidine triphosphates were prepared and enzymatically incorporated into DNA. These modified oligonucleotides were then used for conjugation with DNA binding domain of protein p53.
Keywords:
nucleic acids; DNA; Michael addition
Available at various institutes of the ASCR
Study of DNA-protein interactions by cross-link formation using aqueous Michael addition
Acrylamide and vinylsulfonamide were designed as reactive DNA modifications for covalent crosslinking with cysteine containing peptides and proteins. The corresponding functionalized cytidine ...
Synthesis and biological properties of polysubstituted 5-nitrosopyrimidines
Janeba, Zlatko; Čechová, Lucie; Žurek, Jiří; Procházková, Eliška; Dračínský, Martin
2014 - English
2,4,6-Triamino-5-nitrosopyrimidines have been reported to contain a strong intramolecular hydrogen bond between the 5-nitroso and 4- or 6-amino groups, thus forming an additional pseudoring. Such analogues were speculated to be good mimics of fused bicyclic derivatives, e.g. purines. A series of novel polysubstituted 2-amino-5-nitrosopyrimidines, as potential structural mimics of modifi ed purine nucleos(t)ides well-known for their important biological properties, has been designed and synthesized. The physicochemical and biological properties of the prepared polysubstituted 2-amino-5-nitrosopyrimidines are being evaluated.
Keywords:
polysubstituted 5-nitrosopyrimidines; intramolecular hydrogen bond; NMR spectroscopy
Available at various institutes of the ASCR
Synthesis and biological properties of polysubstituted 5-nitrosopyrimidines
2,4,6-Triamino-5-nitrosopyrimidines have been reported to contain a strong intramolecular hydrogen bond between the 5-nitroso and 4- or 6-amino groups, thus forming an additional pseudoring. Such ...
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