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21.
Phosphatidylinositol 3-kinase-dependent,MEK- independent proliferation in response to CaR activation 总被引:1,自引:0,他引:1
Bilderback TR Lee F Auersperg N Rodland KD 《American journal of physiology. Cell physiology》2002,283(1):C282-C288
Although ovarian surface epithelial(OSE) cells are responsible for the majority of ovarian tumors, we knowrelatively little about the pathway(s) that is responsible forregulating their proliferation. We found that phosphatidylinositol3-kinase (PI3K) is activated in OSE cells in response to elevatedextracellular calcium, and the PI3K inhibitors wortmannin and LY-294002inhibited extracellular signal-regulated kinase (ERK) activation by~75%, similar to effects of the mitogen-activated protein kinase/ERK kinase inhibitor PD-98059. However, in assays of proliferation, we found that PD-98059 inhibited proliferation by ~50%, whereas wortmannin inhibited >90% of the proliferative response to elevated calcium. Expression of a dominant negative PI3K totally inhibited ERKactivation in response to calcium. These results demonstrate that ERKactivation cannot account for the full proliferative effect of elevatedcalcium in OSE cells and suggest the presence of an ERK-independent,PI3K-dependent component in the proliferative response. 相似文献
22.
Evgenia V. Dolgova Yaroslav R. Efremov Konstantin E. Orishchenko Oleg M. Andrushkevich Ekaterina A. Alyamkina Anastasia S. Proskurina Sergey I. Bayborodin Valeriy P. Nikolin Nelly A. Popova Elena R. Chernykh Alexandr A. Ostanin Oleg S. Taranov Vladimir V. Omigov Alexandra M. Minkevich Vladimir A. Rogachev Sergey S. Bogachev Mikhail A. Shurdov 《Gene》2013
We previously reported that fragments of exogenous double-stranded DNA can be internalized by mouse bone marrow cells without any transfection. Our present analysis shows that only 2% of bone marrow cells take up the fragments of extracellular exogenous DNA. Of these, ~ 45% of the cells correspond to CD34 + hematopoietic stem cells. Taking into account that CD34 + stem cells constituted 2.5% of the total cell population in the bone marrow samples analyzed, these data indicate that as much as 40% of CD34 + cells readily internalize fragments of extracellular exogenous DNA. This suggests that internalization of fragmented dsDNA is a general feature of poorly differentiated cells, in particular CD34 + bone marrow cells. 相似文献
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24.
Bombyx mori posterior silkgland cells exhibit an impressive microfilament apparatus located at the cellular apex. It consists of bundles of packed, long microfilaments of 50–70 Å diameter running along circumferences delimiting the lumen of the gland, perpendicularly to the flow of luminal silk. Microfilaments are closely associated with microtubules of the cytoplasmic ‘radial microtubule system’. Immunolabelling with purified antihuman actin antibodies was used to demonstrate their actin-like nature. Apical microfilaments are sensitive to cytochalasin B (CB) which selectively inhibits the secretion of fibroin. Following the removal of the drug, microfilaments recover their normal morphology and secretion resumes. The possible implication of contraction of microfilaments in the process of secretion is discussed. 相似文献
25.
Differential synthesis of glyceraldehyde-3-phosphate dehydrogenase polypeptides in stressed yeast cells 总被引:4,自引:0,他引:4
Helian Boucherié Nelly Bataille Ian T. Fitch Michel Perrot Mick F. Tuite 《FEMS microbiology letters》1995,125(2-3):127-133
Abstract Three unlinked genes, TDH1, TDH2 and TDH3 , encode the glycolytic enzyme glyceraldehyde-3-phosphate dehydrogenase (triose-phosphate dehydrogenase; TDK) in the yeast Saccharomyces cerevisiae . We demonstrate that the synthesis of the three encoded TDK polypeptides (TDHa, TDHb and TDHc, respectively) is not co-ordinately regulated and that TDHa is only synthesised as cells enter stationary phase, due to glucose starvation, or in heat-shocked cells. Furthermore, the synthesis of TDHb, but not TDHc, is strongly repressed by a heat shock. Hence, the TDHa enzyme may play a cellular role, distinct from glycolysis, that is required by stressed cells. 相似文献
26.
Grand André Jorge Nelly Morell Christophe Cadet Jean Eriksson Leif A. 《Journal of molecular modeling》2014,20(6):1-10
Geometric consequences of electron delocalization were studied for all possible adenine tautomers in aqueous solution by means of ab initio methods {PCM(water)//DFT(B3LYP)/6-311+G(d,p)} and compared to those in the gas phase {DFT(B3LYP)/6-311+G(d,p)}. To measure the consequences of any type of resonance conjugation (π-π, n-π, and σ-π), the geometry-based harmonic oscillator model of electron delocalization (HOMED) index, recently extended to the isolated (DFT) and hydrated (PCM//DFT) molecules, was applied to the molecular fragments (imidazole, pyrimidine, 4-aminopyrimidine, and purine) and also to the whole tautomeric system. For individual tautomers, the resonance conjugations and consequently the bond lengths strongly depend on the position of the labile protons. The HOMED indices are larger for tautomers (or their fragments) possessing the labile proton(s) at the N rather than C atom. Solvent interactions with adenine tautomers slightly increase the resonance conjugations. Consequently, they slightly shorten the single bonds and lengthen the double bonds. When going from the gas phase to water solution, the HOMED indices increase (by less than 0.15 units). There is a good relation between the HOMED indices estimated in water solution and those in the gas phase for the neutral and ionized forms of adenine. Subtle effects, being a consequence of intramolecular interactions between the neighboring groups, are so strongly reduced by solvent that the relation between the HOMED indices and the relative energies for the neutral adenine tautomers seems to be better in water solution than in the gas phase. Figure
The total HOMED indices in water solution correlate well with those in the gas phase for the neutral and charged isomers of adenine 相似文献
27.
28.
Torsten Schubert Stephan H. von Reuß Cindy Kunze Christian Paetz Stefan Kruse Peggy Brand-Schön Anita Mac Nelly Jörg Nüske Gabriele Diekert 《Microbial biotechnology》2019,12(2):346-359
Cobamides (Cbas) are essential cofactors of reductive dehalogenases (RDases) in organohalide-respiring bacteria (OHRB). Changes in the Cba structure can influence RDase function. Here, we report on the cofactor versatility or selectivity of Desulfitobacterium RDases produced either in the native organism or heterologously. The susceptibility of Desulfitobacterium hafniense strain DCB-2 to guided Cba biosynthesis (i.e. incorporation of exogenous Cba lower ligand base precursors) was analysed. Exogenous benzimidazoles, azabenzimidazoles and 4,5-dimethylimidazole were incorporated by the organism into Cbas. When the type of Cba changed, no effect on the turnover rate of the 3-chloro-4-hydroxy-phenylacetate-converting enzyme RdhA6 and the 3,5-dichlorophenol-dehalogenating enzyme RdhA3 was observed. The impact of the amendment of Cba lower ligand precursors on RDase function was also investigated in Shimwellia blattae, the Cba producer used for the heterologous production of Desulfitobacterium RDases. The recombinant tetrachloroethene RDase (PceAY51) appeared to be non-selective towards different Cbas. However, the functional production of the 1,2-dichloroethane-dihaloeliminating enzyme (DcaA) of Desulfitobacterium dichloroeliminans was completely prevented in cells producing 5,6-dimethylbenzimidazolyl-Cba, but substantially enhanced in cells that incorporated 5-methoxybenzimidazole into the Cba cofactor. The results of the study indicate the utilization of a range of different Cbas by Desulfitobacterium RDases with selected representatives apparently preferring distinct Cbas. 相似文献
29.
Fine root growth and element concentrations of Norway spruce as affected by wood ash and liquid fertilisation 总被引:2,自引:1,他引:2
M. Genenger S. Zimmermann D. Hallenbarter W. Landolt E. Frossard I. Brunner 《Plant and Soil》2003,255(1):253-264
A field experiment to test various management practices of sustainable forestry was conducted in a Swiss spruce forest for two growing seasons. Treatments were a control (C), yearly application of 4000 kg ha–1 wood ash (A), daily irrigation with a steady state fertilisation as `optimal nutrition` (F) and irrigation with a water control (W). Samples were taken on a 5 × 5 m grid once a year with a soil corer to determine fine root biomass ( 2 mm) and soil pH of the topsoil. A subset of the fine root samples was further analysed for its nutrient composition by CN and ICP-AES analyses. The dynamics of root growth were observed with the aid of ingrowth-cores after 1, 1.5, and 2 years of treatment and the growth pattern was analysed in terms of biomass, tips, forks, length and root diameter of the samples. The A, F and also the W treatment resulted in a significant increase of soil pH in the topsoil. The fine root density increased over the two growing seasons, irrespective of the treatment. The root growth was only slightly different between the treatments with a initially faster growth under the A treatment. The W treatment reduced the number of root tips and forks, and the root length, while the A treatment increased the number of root tips, forks and the root length, but reduced the diameter. The differences between the three harvesting times (March 1999, October 1999, March 2000) of the ingrowth-cores stressed seasonal differences in root growth and the development of quasi `steady state' root dynamics. The root turnover was not changed by the treatments. The elements in the fine roots were strongly affected by the treatments A and F and sometimes by W. Fine root N increased with the F treatment, while C concentrations decreased under the A, F and W treatments. The Ca and Mg concentrations were strongly enhanced by A but also by the F treatment. The K and P concentrations in the fine roots were improved by all three applications. Due to the pH increase Al, Fe and Mn concentrations in the fine roots were decreased by the A and F treatments. S and Zn concentrations showed inconsistent changes over the growing seasons. The results of this study were comparable with those of other studies in Europe and confirm the abilities of the fine roots as indicators of forest nutrition, to some extent more sensitive than the commonly used foliar analysis. 相似文献
30.
Ekaterina A. Alyamkina Anastasia S. Likhacheva Tamara E. Sebeleva Nelly A. Popova Elena V. Kiseleva Ludmila V. Sakhno Alexandr A. Ostanin Stanislav N. Zagrebelniy Mikhail A. Shurdov 《Cellular immunology》2010,262(2):120-126
Exogenous allogenic DNA as nucleosome-free fragments reaches main cellular compartments (cytoplasm, nucleus) of human dendritic cells and deposits in the nuclear interchromosomal space without visibly changing in linear size. The presence of such allogenic fragmented DNA in medium in which human dendritic cells are cultured produces an enhancement of their allostimulatory activity. This enhancement is comparable to that produced by the standard maturation stimulus lipopolysaccharide Escherichia coli. 相似文献