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211.
Uday Ghanty Tong Wang Rahul M. Kohli 《Angewandte Chemie (International ed. in English)》2020,59(28):11312-11315
TET family enzymes are known for oxidation of the 5‐methyl substituent on 5‐methylcytosine (5mC) in DNA. 5mC oxidation generates the stable base 5‐hydroxymethylcytosine (5hmC), starting an indirect, multi‐step process that ends with reversion of 5mC to unmodified cytosine. While probing the nucleobase determinants of 5mC recognition, we discovered that TET enzymes are also proficient as direct N‐demethylases of cytosine bases. We find that N‐demethylase activity can be readily observed on substrates lacking a 5‐methyl group and, remarkably, TET enzymes can be similarly proficient in either oxidation of 5mC or demethylation of N4‐methyl substituents. Our results indicate that TET enzymes can act as both direct and indirect demethylases, highlight the active‐site plasticity of these FeII/α‐ketoglutarate‐dependent dioxygenases, and suggest activity on unexplored substrates that could reveal new TET biology. 相似文献
212.
Keesari Tirumalesh Chatterjee Sitangshu Pant Diksha Kumar Mukund Sakhare Vishal Sinha Uday Kumar Mohokar Hemant Jaryal Ajay Roy Annadasankar Maitra Asmita 《Journal of Radioanalytical and Nuclear Chemistry》2020,323(3):1227-1235
Journal of Radioanalytical and Nuclear Chemistry - In this study environmental radioisotopes of water (3H and 14C) were used to determine the residence time of thermal waters. The temperature of... 相似文献
213.
Saha UC Dhara K Chattopadhyay B Mandal SK Mondal S Sen S Mukherjee M van Smaalen S Chattopadhyay P 《Organic letters》2011,13(17):4510-4513
A new probe, 3-[(3-benzyloxypyridin-2-ylimino)methyl]-2-hydroxy-5-methylbenzaldehyde (1-H) behaves as a highly selective fluorescent pH sensor in a Britton-Robinson buffer at 25 °C. The pH titrations show a 250-fold increase in fluorescence intensity within the pH range of 4.2 to 8.3 with a pK(a) value of 6.63 which is valuable for studying many of the biological organelles. 相似文献
214.
Florian J. Stadler Merina Rajan Uday S. Agarwal Chen-Yang Liu K. E. George Piet J. Lemstra Christian Bailly 《Rheologica Acta》2011,50(5-6):491-501
We investigate the linear and non-linear rheological behavior in shear of a concentrated solution of ??dumbbell?? polystyrene with long linear backbone and dense short brushes at both ends and compare it with corresponding linear polymers. This type of dumbbells has never been rheologically characterized before. In linear viscoelasticity, the dumbbell polymers show significant differences with conventional linear polymers. In particular, the reptation relaxation of the dumbbell is strongly slowed down. Furthermore, the addition of the side chains increases the friction so that the dumbbell lies above the ?? 0 vs. number of entanglements relation of linear samples. Transient shear rheology experiments on weakly entangled solutions show a retardation of the chain stretch relaxation of the dumbbell by a factor 2.5 vs. a linear polymer with the same Rouse time. Additionally, a second peak in the transient viscosity is observed at high shear rates. 相似文献
215.
Prabhu UR Baishya B Suryaprakash N 《Journal of magnetic resonance (San Diego, Calif. : 1997)》2008,193(2):259-266
The differential values of NMR spectral parameters like chemical shift anisotropies, dipolar couplings and quadrupolar couplings of enantiomers in chiral liquid crystalline media are employed not only for their visualization but also for their quantification. Large differences in chemical shift anisotropies and the quadrupolar couplings between the enantiomers enable the use of 13C and extensive 2H NMR detection for such a purpose. In spite of high magnetic moment, high sensitivity and abundant presence of protons in all the chiral molecules, 1H detection is not routinely employed due to severe overlap of unresolved transitions arising from short and long distance couplings. Furthermore, the doubling of the spectra from two enantiomers and their indistinguishable overlap due to negligible difference in chemical shift anisotropies hampers their discrimination. The present study demonstrates the use of proton chemical shift anisotropy as an exclusive parameter for such a discrimination. The method employs the non-selective excitation of homonuclear Nth quantum coherence of N coupled protons. The simultaneous flipping of all the coupled spins results in a single transition in the multiple quantum dimension at the cumulative sum of their anisotropic chemical shifts for each enantiomer, with the measurable difference between them, resulting in their complete unraveling. 相似文献
216.
The authors consider a quarter-symmetric metric connection in a P-Sasakian manifold and study the second order parallel tensor in a P-Sasakian manifold with respect to the quarter-symmetric metric connection. Then Ricci semisymmetric P-Sasakian manifold with respect to the quarter-symmetric metric connection is considered. Next the authors study ξ-concircularly flat P-Sasakian manifolds and concircularly semisymmetric P-Sasakian manifolds with respect to the quarter-symmetric metric connection. ... 相似文献
217.