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91.
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Sulzer P Ptasinska S Zappa F Mielewska B Milosavljevic AR Scheier P Märk TD Bald I Gohlke S Huels MA Illenberger E 《The Journal of chemical physics》2006,125(4):44304
We study dissociative electron attachment to furan (FN) (C(4)H(4)O), tetrahydrofuran (THF) (C(4)H(8)O), and fructose (FRU) (C(6)H(12)O(6)) using crossed electron/molecular beams experiments with mass spectrometric detection of the anions. We find that FN and THF are weak electron scavengers and subjected to dissociative electron attachment essentially in the energy range above 5.5 eV via core excited resonances. In striking contrast to that, FRU is very sensitive towards low energy electrons generating a variety of fragment ions via a pronounced low energy feature close to 0 eV. These reactions are associated with the degradation of the ring structure and demonstrate that THF cannot be used as surrogate to model deoxyribose in DNA with respect to the attack of electrons at subexcitation energies (<3 eV). The results support the picture that in DNA the sugar moiety itself is an active part in the initial molecular processes leading to single strand breaks. 相似文献
93.
Natalia Festinger Sylwia Smarzewska Valentin Mirčeski Witold Ciesielski 《Electroanalysis》2021,33(2):314-322
In this study, a simple and sensitive square wave voltammetric procedure has been developed for the determination of acemetacin (ACM) at graphite flake paste electrode (GFPE) and glassy carbon electrode (GCE). Under optimized conditions, the dependence of ACM peak current on its concentration showed wide linear range: 0.03–1.0 μmol L−1 and 0.7–15.0 μmol L−1 at GFPE and GCE, respectively. The developed method was successfully applied for the determination of ACM in pharmaceuticals and spiked urine with satisfying recoveries. The electrochemical oxidation of ACM is an irreversible process controlled by mixed nature of the mass transfer process. 相似文献
94.
Kamil Piwowarek Edyta Lipiska Elbieta Ha-Szymaczuk Anna Maria Kot Marek Kieliszek Sylwia Bonin 《Molecules (Basel, Switzerland)》2021,26(13)
Propionic acid bacteria are the source of many metabolites, e.g., propionic acid and trehalose. Compared to microbiological synthesis, the production of these metabolites by petrochemical means or enzymatic conversion is more profitable. The components of microbiological media account for a large part of the costs associated with propionic fermentation, due to the high nutritional requirements of Propionibacterium. This problem can be overcome by formulating a medium based on the by-products of technological processes, which can act as nutritional sources and at the same time replace expensive laboratory preparations (e.g., peptone and yeast extract). The metabolic activity of P. freudenreichii was investigated in two different breeding environments: in a medium containing peptone, yeast extract, and biotin, and in a waste-based medium consisting of only apple pomace and potato wastewater. The highest production of propionic acid amounting to 14.54 g/L was obtained in the medium containing apple pomace and pure laboratory supplements with a yield of 0.44 g/g. Importantly, the acid production parameters in the waste medium reached almost the same level (12.71 g/L, 0.42 g/g) as the medium containing pure supplements. Acetic acid synthesis was more efficient in the waste medium; it was also characterized by a higher level of accumulated trehalose (59.8 mg/g d.s.). Thus, the obtained results show that P. freudenreichii bacteria exhibited relatively high metabolic activity in an environment with apple pomace used as a carbon source and potato wastewater used as a nitrogen source. This method of propioniate production could be cheaper and more sustainable than the chemical manner. 相似文献
95.
Renata Kasprzyk Beata J. Starek Sylwia Ciechanowicz Dorota Kubacka Joanna Kowalska Jacek Jemielity 《Chemistry (Weinheim an der Bergstrasse, Germany)》2019,25(27):6728-6740
The m7G cap is a unique nucleotide structure at the 5′-end of all eukaryotic mRNAs. The cap specifically interacts with numerous cellular proteins and participates in biological processes that are essential for cell growth and function. To provide small molecular probes to study important cap-recognizing proteins, we synthesized m7G nucleotides labeled with fluorescent tags via the terminal phosph(on)ate group and studied how their emission properties changed upon protein binding or enzymatic cleavage. Only the pyrene-labeled compounds behaved as sensitive turn-on probes. A pyrene-labeled m7GTP analogue showed up to eightfold enhanced fluorescence emission upon binding to eukaryotic translation initiation factor 4E (eIF4E) and over 30-fold enhancement upon cleavage by decapping scavenger (DcpS) enzyme. These observations served as the basis for developing binding- and hydrolytic-activity assays. The assay utility was validated with previously characterized libraries of eIF4E ligands and DcpS inhibitors. The DcpS assay was also applied to study hydrolytic activity and inhibition of endogenous enzyme in cytoplasmic extracts from HeLa and HEK cells. 相似文献
96.
97.
Sylwia Studzińska Rafał Rola Bogusław Buszewski 《Analytical and bioanalytical chemistry》2016,408(6):1585-1595
98.
Miriam M. Schwab Daniel Himmel Sylwia Kacprzak Daniel Kratzert Valentin Radtke Philippe Weis Kallol Ray Ernst‐Wilhelm Scheidt Wolfgang Scherer Bas deBruin Stefan Weber Ingo Krossing 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2015,127(49):14919-14922
The straightforward synthesis of the cationic, purely organometallic NiI salt [Ni(cod)2]+[Al(ORF)4]− was realized through a reaction between [Ni(cod)2] and Ag[Al(ORF)4] (cod=1,5‐cyclooctadiene). Crystal‐structure analysis and EPR, XANES, and cyclic voltammetry studies confirmed the presence of a homoleptic NiI olefin complex. Weak interactions between the metal center, the ligands, and the anion provide a good starting material for further cationic NiI complexes. 相似文献
99.
Whole genome amplification induced bias in the detection of KRAS‐mutated cell populations during colorectal carcinoma tissue testing 下载免费PDF全文
Jana Stranska Sylwia Jancik Rastislav Slavkovsky Veronika Holinkova Miroslava Rabcanova Petr Vojta Marian Hajduch Jiri Drabek 《Electrophoresis》2015,36(6):937-940
Whole genome amplification replicates the entire DNA content of a sample and can thus help to circumvent material limitations when insufficient DNA is available for planned genetic analyses. However, there are conflicting data in the literature whether whole genome amplification introduces bias or reflects precisely the spectrum of starting DNA. We analyzed the origins of discrepancies in KRAS (Kirsten rat sarcoma viral oncogene homolog gene) mutation detection in six of ten samples amplified using the GenomePlex® Tissue Whole Genome Amplification kit 5 (WGA5; Sigma‐Aldrich, St. Louis, MO, USA) and KRAS StripAssay® (KRAS SA; ViennaLab Diagnostics, Vienna, Austria). We undertook reextraction, reamplification, retyping, authentication, reanalysis, and reinterpretation to determine whether the discrepancies originated during the preanalytical, analytical, and/or interpretative phase of genotyping. We conclude that a combination of glass slide/sample heterogeneity and biased amplification due to stochastic effects in the early phases of whole genome amplification (WGA) may have adversely affected the results obtained. Our findings are relevant for both forensic genetics testing and massively parallel sequencing using preamplification. 相似文献
100.