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91.
Ultrasensitive Direct Quantification of Nucleobase Modifications in DNA by Surface‐Enhanced Raman Scattering: The Case of Cytosine 下载免费PDF全文
Judit Morla‐Folch Dr. Hai‐nan Xie Patricia Gisbert‐Quilis Dr. Sara Gómez‐de Pedro Dr. Nicolas Pazos‐Perez Prof. Dr. Ramon A. Alvarez‐Puebla Dr. Luca Guerrini 《Angewandte Chemie (International ed. in English)》2015,54(46):13650-13654
Recognition of chemical modifications in canonical nucleobases of nucleic acids is of key importance since such modified variants act as different genetic encoders, introducing variability in the biological information contained in DNA. Herein, we demonstrate the feasibility of direct SERS in combination with chemometrics and microfluidics for the identification and relative quantification of 4 different cytosine modifications in both single‐ and double‐stranded DNA. The minute amount of DNA required per measurement, in the sub‐nanogram regime, removes the necessity of pre‐amplification or enrichment steps (which are also potential sources of artificial DNA damages). These findings show great potentials for the development of fast, low‐cost and high‐throughput screening analytical devices capable of detecting known and unknown modifications in nucleic acids (DNA and RNA) opening new windows of activity in several fields such as biology, medicine and forensic sciences. 相似文献
92.
Gréta Gergely Ferenc Wéber István Lukács Levente Illés Attila L. Tóth Zsolt E. Horváth Judit Mihály Csaba Balázsi 《Central European Journal of Chemistry》2010,8(2):375-381
Hydroxyapatite (HAp) was successfully produced from recycled eggshell, seashell and phosphoric acid. The phases obtained depended
on the ratio of calcined eggshell/ seashell to phosphoric acid, the calcination temperature and the mechanochemical activation
method (ball milling or attrition milling). The HAp structures were characterized by X-ray diffraction, scanning electron
microsopy and infrared spectroscopy. Attrition milling was more effective than ball milling, yielding nanosize, homogenous
and pure Hap.
相似文献
93.
Schmidt KS Reedijk J Weisz K Basilio Janke EM Sponer JE Sponer J Lippert B 《Inorganic chemistry》2002,41(11):2855-2863
Chloroform- and Freon-soluble mixed thymine, adenine complexes trans-[Pt(MeNH(2))(2)(ChmT-N3)(ChmA-N1)]NO(3) (2) and trans-[Pt(MeNH(2))(2)(ChmT-N3)(TBDMS-ado-N1)]BF(4) (3) (ChmT = anion of 1-cyclohexylmethylthymine ChmTH, ChmA = 9-cyclohexylmethyladenine, TBDMS-ado = 2',3',5'-tri-tert-butyldimethylsilyladenosine) have been prepared and characterized to study their propensity to undergo Hoogsteen and/or reversed Hoogsteen pairing in solution with free ChmTH and free 3',5'-diacetyl-2'-deoxyuridine, respectively. No Hoogsteen or reversed Hoogsteen pairing between 2 and ChmT takes place in CDCl(3). In Freon, partial H bonding between N1 platinated TBDMS-ado and 3',5'-diacetyl-2'-deoxyuridine as well as its [3-(15)N] labeled analogue is unambiguously observed only below 150 K. Comparison of (1)J ((15)N-(1)H) coupling constants of 3',5'-diacetyl-2'-deoxyuridine involved in Hoogsteen pairing with free and N1 platinated adenine suggests that the interaction is inherently weaker in the case of platinated adenine. To better understand the complete absence of hydrogen bonding between the ChmA ligand in 2 and free ChmTH, ab initio calculations (gas phase, 0 K) have been carried out for Hoogsteen pairs involving adenine (A) and thymine (T), as well as simplified analogues of 2 and T, both in the presence and absence of counteranions. The data strongly suggest that reduction of the effective positive charge of the heavy metal ion Pt(2+) by counterions diminishes interaction energies. With regard to mixtures of 2 and ChmTH in chloroform, this implies that ion pair formation between the cation of 2 and NO(3)(-) may be responsible for the lack of any measurable Hoogsteen pairing in this solvent. 相似文献
94.
Basarić N Horvat M Mlinarić-Majerski K Zimmermann E Neudörfl J Griesbeck AG 《Organic letters》2008,10(18):3965-3968
The photochemical reaction of N-(1-adamantyl)phthalimide (1) gives cleanly one product, the novel hexacyclic benzazepine derivative of 2,4-methanoadamantane 2. Its structure was characterized by spectroscopic methods and X-ray analysis and represent the first example of the 2-azahexacyclo[8.7.1.1 (1,4).0 (4,9).0 (11,16).0 (12,18)]nonadeca-4,6,8-triene skeleton. The product is formed by a domino process of two consecutive excited-state intramolecular gamma-hydrogen-transfer reactions. Base hydrolysis of the benzazepine 2 gives in high yield the keto derivative of the 1,2-substituted adamantane epsilon-amino acid 3. 相似文献
95.
Summary: We recently reported the synthesis of polyisobutylene (PIB) via direct initiation by epoxycyclohexyl isobutyl polyhedral oligomeric silsesquioxane (POSS®) (Figure 1 ) in conjunction with titanium tetrachloride (TiCl4). This system successfully initiated the living carbocationic polymerization of isobutylene (IB) in hexane/methyl chloride (Hx/MeCl -60/40, v/v) at T = −80 °C, yielding an asymmetric telechelic PIB with one POSS® cage head group and one tert-Cl end group. 1 This paper will discuss IB polymerizations initiated by 1,2-epoxycyclohexane and bis[3,4-(epoxycyclohexyl)ethyl]-tetramethyl-disiloxane, in conjunction with TiCl4. 相似文献
96.
Judit E. Puskas Yaohong Chen Kevin Kulbaba Gabor Kaszas Ali Soleymannezhad 《Journal of polymer science. Part A, Polymer chemistry》2006,44(5):1770-1776
This article discusses the characterization of arborescent (hyperbranched) polyisobutylenes (arb‐PIBs) by size exclusion chromatography and differential scanning calorimetry, in comparison with linear PIB standards. The radius of gyration (〈r〉1/2 = Rz), measured from the angle dependence of light scattering of high‐molecular‐weight arb‐PIBs, was significantly larger than the hydrodynamic radius (Rh) from size exclusion chromatography/viscometry, and the Rh values were significantly smaller than Rh of linear PIBs. The glass‐transition temperature of arb‐PIBs having a branch molecular weight higher than the critical entanglement molecular weight was dependent on both the total number‐average molecular weight and BR up to BR ~ 15. A modified Fox–Flory equation is proposed to describe the effect of architecture on the thermal transition. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 1770–1776, 2006 相似文献
97.
New host molecules for anions, adamantane, and alkyl urea derivatives substituted by naphthalene chromophores, were synthesized. Their binding with F−, Cl−, Br−, OAc−, HSO4−, NO3−, and H2PO4− was investigated by UV-vis, fluorescence and NMR spectroscopy. The anion binding ability of adamantyl bisurea derivatives was compared with the analogous host molecules, wherein the urea moieties are separated by flexible alkyl linkers of the same length, and adamantane monourea derivative. The host molecules show the highest selectivity toward F− and H2PO4−. The binding stoichiometry and the values of the association constants depend on the basicity of anions, availability of H-bonding sites, preorganization, and rigidity of the hosts, as well as solvent polarity and H-bonding availability. Rigid adamantane receptors, compared to flexible analogues show increased selectivity for H2PO4−, whereas binding of OAc− is better with flexible receptors. The binding of OAc− and H2PO4− was investigated by microcalorimetry. The stoichiometries and the stability constants of the corresponding complexes obtained by this method were in good agreement compared to those determined by UV-vis titrations. In both cases the enthalpic contribution to the overall complex stability was predominant. 相似文献
98.
Steroidal 17-hydroxamic acid derivatives were synthesized in high yields in palladium-catalysed carbonylation reaction of 17-iodo-androst-16-ene derivatives under mild reaction conditions. 相似文献
99.
Acotoxinine ( 1 ), a new norditerpene alkaloid, was isolated from the roots of Aconitum toxicum Rchb ., together with the structurally related C19 diterpene alkaloids neoline ( 2 ) and aconitine ( 3 ) and C20 diterpene alkaloids songorine ( 4 ) and songoramine ( 5 ). The structures were elucidated by HR‐MS and advanced NMR methods, including 1H‐NMR, JMOD, 1H,1H‐COSY, HSQC, and HMBC experiments. This is the first report of C20 diterpenoid alkaloids in Aconitum toxicum. 相似文献
100.
Rubí Zamudio-Vázquez Sa?ka Ivanova Miguel Moreno Maria Isabel Hernandez-Alvarez Ernest Giralt Axel Bidon-Chanal Antonio Zorzano Fernando Albericio Judit Tulla-Puche 《Chemical science》2015,6(8):4537-4549
The synthesis of a new small library of quinoxaline-containing peptides is described. After cytotoxic evaluation in four human cancer cell lines, as well as detailed biological studies, it was found that the most active compound, RZ2, promotes the formation of acidic compartments, where it accumulates, blocking the progression of autophagy. Further disruption of the mitochondrial membrane potential and an increase in mitochondrial ROS was observed, causing cells to undergo apoptosis. Given its cytotoxic activity and protease-resistant features, RZ2 could be a potential drug candidate for cancer treatment and provide a basis for future research into the crosstalk between autophagy and apoptosis and its relevance in cancer therapy. 相似文献