Results 1 - 10 of 391
Results 1 - 10 of 391. Search took: 0.024 seconds
|Sort by: date | relevance|
[en] Apoptosis in Xenopus egg extracts is carried out by maternally stockpiled materials, but the contributions of endogenous apoptosis regulators are still poorly characterized. Here we examined the physiological role of Xenopus Bid (xBid), a pro-apoptotic BH3-only member of Bcl-2 family proteins. We found that endogenous xBid was a physiological accelerator of apoptosis in egg extracts. Interestingly, xBid was mono-/diubiquitylated but not degraded by proteasome in egg extracts, and we identified three ubiquitylated Lys residues in the N-terminal propeptide region. Comparison with human Bid suggested that mono-/diubiquitylation is a specific feature of xBid.
[en] Highlights: • Organic microstructural materials fabricated by solid-phase anion exchange reactions. • The solvent-induced morphological changes. • Solvent type (protic/aprotic)/polarity can significantly tune the morphologies. • The sheetlike morphologies reveal enhanced photophysical properties. • Unusual three-dimensional hexangular prismlike or cubelike morphologies.
[en] The purpose of this paper is the characterization of a plasma-doping system in BF3. Energy distributions (IEDs) of boron ions crossing a high-voltage sheath (up to 1 kV) are measured in a BF3 plasma under different experimental conditions. It is demonstrated that relative percentages of boron ions reaching the cathode and IED shapes are governed by the number of collisions inside the sheath. Heavy molecular ions (B2F5+, B2F3+ ) are dissociated inside the sheath and light boron ions (B+, BF+) are created. Based on experimental results and ab initio calculations of boron ion structures, the mechanisms occurring in the sheath are discussed. Furthermore, the charge exchange cross-section between BF3+ and BF3 is estimated to be 8.8 × 10−19 m2. (paper)
[en] Two groups of compounds differing in the crystal supramolecular architecture and luminescence properties have been identified in a series of boron difluoride benzoylacetonates. In the case of the first group, the luminescence spectra of saturated solutions are bathochromically shifted relative to those of crystals. Molecules of the compounds of the first group are organized into infinite stacks with just one type of overlapping. The quantum-chemistry simulation demonstrates that the geometry of dimers in a crystal, unlike that in saturated solutions is not optimal. J-aggregates composed of dimers of the geometry similar to the optimal one are formed in crystals of the compounds of the second group. The luminescence spectra of saturated solutions and crystals of the second group compounds are identical.
[en] We have been investigating the immunological effects of asbestos. The establishment of a low-dose and continuously exposed human T cell line, HTLV-1 immortalized MT-2, to chrysotile (CB) revealed reduction of CXCR3 chemokine receptor and production of IFN-γ that caused a decline of tumor immunity. These effects were coupled with upregulation of IL-10, TGF-β, and BCL-2 in asbestos-exposed patients. To observe the immunological effects of crocidolite (CR) on human T cells, a trial to establish a low-dose and continuously exposed model was conducted and compared with a previously reported CB-exposed model (MT-2CB). Transient exposure of MT-2 original cells to CB or CR induced a similar level of apoptosis and growth inhibition. The establishment of a continuously exposed subline to CR (MT-2CR) revealed resistance against CR-induced apoptosis and upregulation of the BCL-2/BAX ratio similar to that recorded for MT-2CB. Both sublines showed reduced production of IFN-γ, TNF-α, and IL-6 with increased IL-10. cDNA microarray with network/pathway analyses focusing on transcription factors revealed that many similar factors related to cell proliferation were involved following continuous exposure to asbestos in both MT-2CB and MT-2CR. These results indicate that both CB and CR fibers affect human T cells with similar degrees even though the carcinogenic activity of these substances differs due to their chemical and physical forms. Trials to identify early detection markers for asbestos exposure or the occurrence of asbestos-inducing malignancies using these findings may lead to the development of clinical tools for asbestos-related diseases and chemoprevention that modifies the reduced tumor immunity. - Highlights: ► Comparison of effects of chrysotile and crocidolite on human T cell was done. ► Both fibers caused apoptosis of T cells by transient exposure. ► T cells acquired resistance to asbestos-induced apoptosis when both fibers had been exposed continuously. ► Both fibers caused similar changes in cDNA array and network/pathway analyses using continuously exposed T cells.
[en] The luminescence-spectral, lasing and photochemical characteristics of laser media based on boron fluoride complexes of dipyrromethenes, embedded into solid bulk matrices of polymethylmethacrylate and its modifications (obtained by adding polyhedral oligomeric silsesquioxane during polymerisation) and into polymer films, in which polyhedral silsesquioxane enters the composition of monomeric unit, have been investigated. (lasers)
[en] Many method has been used to optimize the possible ground state structures of BCI and BCI2 by the multi-basis set. The results show that the ground state of BCI molecule is of X1 Σ state, RBCI =0.17159 nm, ωe =837.0003 cm-1 with B3P86 / 6-311 + + G (3 df). The ground state of BCI2 molecule is of 2A1 state, the parameters of structure are RBCI =0.17284 nm, βCIBCI=125.3466 degree, De=8.0592 eV with QCISD/6-31G (d, p). And the harmonic frequency have calculationed at the same time. The potential energy functions of BCI2 have been derived from the many-body expansion theory. The potential energy functions describe correctly the configurations and the dissociation energies of the two ground-state molecules. Molecular reaction kinetics of CI + BCI and B + CICI based on the potential energy functions is discussed briefly, which is successfully used for describing molecular reaction dynamics. (authors)
[en] Recent studies have shown that up-regulation of autophagy may be a tractable therapeutic intervention for clearing disease-causing proteins, including α-synuclein, ubiquitin, and other misfolded or aggregated proteins in pesticide-induced neurodegeneration. In a previous study, we reported that chlorpyrifos (CPF)-induced mitochondria-dependent apoptosis is mediated through reactive oxygen species in SH-SY5Y cells. In this study, we explored a novel pharmacotherapeutic approach to prevent CPF neurotoxicity involving the regulation of autophagy. We investigated the modulation of CPF-induced apoptosis according to autophagy regulation. We found that CPF induced apoptosis in SH-SY5Y cells, as demonstrated by the activation of caspase-3 and nuclear condensation. In addition, we observed that cells treated with CPF underwent autophagic cell death by monitoring the expression of LC3-II and p62. Pretreatment with the autophagy inducer rapamycin significantly enhanced the cell viability of CPF-exposed cells, and the enhancement of cell viability was partially due to alleviation of CPF-induced apoptosis via a decrease in levels of cleaved caspase-3. Specifically, rapamycin pretreatment decreased Bax and increased Bcl-2 expression in mitochondria. In addition, rapamycin significantly decreased cytochrome c release in from mitochondria into the cytosol. However, pretreatment of cells with the autophagy inhibitor, 3-methyladenine (3MA), remarkably increased CPF toxicity in these cells; this with correlated with increased expression of Bax and decreased expression of Bcl-2 in mitochondria. Our results suggest that CPF-induced cytotoxicity is modified by autophagy regulation and that rapamycin protects against CPF-induced apoptosis by enhancing autophagy. Pharmacologic induction of autophagy by rapamycin may be a useful treatment strategy in neurodegenerative disorders. - Highlights: ► Chlorpyrifos (CPF) is cytotoxic to SH-SY5Y cells ► CPF-induced cytotoxicity is mediated by apoptosis ► CPF induces autophagy in SH-SY5Y cells ► Autophagy regulates CPF-induced apoptosis in SH-SY5Y cells
[en] It has been proven that over-expression of surviving in cancerous cell lines is related to the radioresistance of cells to high-LET radiation in previous work. In this study, action mechanisms of surviving gene in apoptosis induced by high-LET radiation were investigated. We found that inhibiting surviving by siRNA had no notable influence on Bcl-2 and Bax expressions induced by carbon ions. Surviving depressed cell apoptosis through the inhibition of the activities of caspase-3 and -9 possibly in cell apoptosis induced by high-LET radiation. (authors)