Search results for "S Phase"
showing 10 items of 146 documents
Epigenetic Transcriptional Regulation of the Growth Arrest-Specific gene 1 (Gas1) in Hepatic Cell Proliferation at Mononucleosomal Resolution
2011
Background Gas1 (growth arrest-specific 1) gene is known to inhibit cell proliferation in a variety of models, but its possible implication in regulating quiescence in adult tissues has not been examined to date. The knowledge of how Gas1 is regulated in quiescence may contribute to understand the deregulation occurring in neoplastic diseases. Methodology/Principal Findings Gas1 expression has been studied in quiescent murine liver and during the naturally synchronized cell proliferation after partial hepatectomy. Chromatin immunoprecipitation at nucleosomal resolution (Nuc-ChIP) has been used to carry out the study preserving the in vivo conditions. Transcription has been assessed at real …
DNA adduct levels associated with p53 induction and delay of MCF-7 cells in S phase after exposure to benzo[g]chrysene dihydrodiol epoxide enantiomer…
1998
Optically active isomers of a mammary carcinogen, anti-benzo[g]chrysene 11, 12-dihydrodiol 13, 14-epoxide, react to different extents with DNA and generate DNA adducts that differ in their stereochemistry. In the study reported here, the effect of these two enantiomers on the progress of human breast carcinoma MCF-7 cells through the cell cycle was investigated. Each enantiomer caused the cells to accumulate in the S phase, but a higher dose of the benzo[g]chrysene 11S, 12R-dihydrodiol 13R, 14S-epoxide than of its enantiomer was required to induce this effect. Similarly, induction of p53 also required a higher dose of benzo[g]chrysene 11S, 12R-dihydrodiol 13R, 14S-epoxide. Postlabeling stud…
Instantaneous frequency measurement of dissipative soliton resonant light pulses
2016
Fil: Cuadrado-Laborde, Christian. Universidad de Valencia. Departamento de Física Aplicada y Electromagnetismo. Instituto Universitario de Ciencia de los Materiales; España Fil: Cuadrado-Laborde, Christian. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Física Rosario; Argentina Fil: Cuadrado-Laborde, Christian. Pontificia Universidad Católica Argentina. Facultad de Química e Ingeniería del Rosario; Argentina Fil: Armas Rivera, I. Benemérita Universidad Autónoma de Puebla. Facultad de Ciencias Físico Matemáticas; Mexico Fil: Carrascosa, A. Universidad de Valencia. Departamento de Física Aplicada y Electromagnetismo. Instituto Universitario de Ciencia de los Materia…
Basis set and correlation effects in the calculation of accurate gas phase dimerization energies of two M+2 to give M2+4 (M = S, Se)
2000
The dimerization energies of two M2+ to give M42+ (M = S, Se) were calcd. They depend strongly on the size of the basis set and the correlation method used (ranging from 217 to 522 kJ/mol, M = S) and, therefore, a systematic study of basis set and correlation effects was performed [MP2, MP3, MP4(SDQ), CCSD, CCSD(T)]. The introduction of a second set of polarizing d-functions caused a significant redn. of the dimerization energies, but neither of the above limits is reached by the MPn (n = 2, 3, 4) theory, even with the largest basis sets [cc-pVQZ]. However, convergence was achieved by CCSD(T), compd. methods or hybrid HF/DFT calcns. employing flexible basis sets [e.g., CCSD(T)/cc-pV5Z, CBS-…
Doppler Shift Characterization of Wideband Mobile Radio Channels
2019
The prevailing approach for characterizing the Doppler shift (DS) of mobile radio channels assumes the transmission of an unmodulated carrier. This consideration is valid for the analysis of narrowband channels, but its pertinence is questionable in regards to the modeling of wideband channels. In this correspondence, we redefine the DS from a time-frequency analysis perspective that does not depend on the aforementioned assumption. We systematically demonstrate that the DS can be characterized by the instantaneous frequency of the channel transfer function. This generic definition makes evident a fundamental aspect of the DS that is seldom acknowledged, namely, the DS is a frequency-varyin…
A density functional theory evaluation of hydrophobic solvation: Ne, Ar and Kr in a 50-water cluster – Implications for the hydrophobic effect
2012
The physical explanation for the hydrophobic effect has been the subject of disagreement. Physical organic chemists tend to use a explanation related to pressure, while many biochemists prefer an explanation that involves decreased entropy of the aqueous solvent. We present DFT calculations at the B3LYP/6-31G(d,p) and X3LYP/6-31G(d,p) levels on the solvation of three noble gases (Ne, Ar, and Kr) in clusters of 50 waters. Vibrational analyses show no substantial decreases in the vibrational entropies of the waters in any of the three clusters. The observed positive free energies of transfer from the gas phase or from nonpolar solvents to water appear to be due to the work needed to make a su…
Efficient simulation of the random-cluster model
2013
The simulation of spin models close to critical points of continuous phase transitions is heavily impeded by the occurrence of critical slowing down. A number of cluster algorithms, usually based on the Fortuin-Kasteleyn representation of the Potts model, and suitable generalizations for continuous-spin models have been used to increase simulation efficiency. The first algorithm making use of this representation, suggested by Sweeny in 1983, has not found widespread adoption due to problems in its implementation. However, it has been recently shown that it is indeed more efficient in reducing critical slowing down than the more well-known algorithm due to Swendsen and Wang. Here, we present…
Coupled cluster calculations of the vertical excitation energies of tetracyanoethylene
2003
The vertical spectrum of tetracyanoethylene was studied using coupled cluster theory. It was found that the lowest singlet-singlet transition, which corresponds to the excitation from the highest occupied molecular orbital (HOMO) to the lowest unoccupied molecular orbital (LUMO) excitation, occurs at 5.16 eV in the gas phase and is lowered approximately 0.1 eV due to solvent effects in acetonitrile. A parallel study on the ethene spectrum showed the quality of the basis sets and methods used, by placing the V state 7.92 eV above the ground state and giving an energy for the 0-0 transition of 5.42 eV to be compared with the experimental value of 5.50 eV.
The role of reactive oxygen species and subsequent DNA-damage response in the emergence of resistance towards resveratrol in colon cancer models
2014
AbstractIn spite of the novel strategies to treat colon cancer, mortality rates associated with this disease remain consistently high. Tumour recurrence has been linked to the induction of resistance towards chemotherapy that involves cellular events that enable cancer cells to escape cell death. Treatment of colon cancer mainly implicates direct or indirect DNA-damaging agents and increased repair or tolerances towards subsequent lesions contribute to generate resistant populations. Resveratrol (RSV), a potent chemosensitising polyphenol, might share common properties with chemotherapeutic drugs through its indirect DNA-damaging effects reported in vitro. In this study, we investigated how…
The bacterial cytolethal distending toxin (CDT) triggers a G2 cell cycle checkpoint in mammalian cells without preliminary induction of DNA strand br…
1999
The bacterial cytolethal distending toxin (CDT) was previously shown to arrest the tumor-derived HeLa cell line in the G2-phase of the cell cycle through inactivation of CDK1, a cyclin-dependent kinase whose state of activation determines entry into mitosis. We have analysed the effects induced in HeLa cells by CDT, in comparison to those induced by etoposide, a prototype anti-tumoral agent that triggers a G2 cell cycle checkpoint by inducing DNA damage. Both CDT and etoposide inhibit cell proliferation and induces the formation of enlarged mononucleated cells blocked in G2. In both cases, CDK1 from arrested cells could be re-activated both in vitro by dephosphorylation by recombinant Cdc25…