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51.
Detecting tumor response to treatment using hyperpolarized 13C magnetic resonance imaging and spectroscopy 总被引:2,自引:0,他引:2
Day SE Kettunen MI Gallagher FA Hu DE Lerche M Wolber J Golman K Ardenkjaer-Larsen JH Brindle KM 《Nature medicine》2007,13(11):1382-1387
Measurements of early tumor responses to therapy have been shown, in some cases, to predict treatment outcome. We show in lymphoma-bearing mice injected intravenously with hyperpolarized [1-(13)C]pyruvate that the lactate dehydrogenase-catalyzed flux of (13)C label between the carboxyl groups of pyruvate and lactate in the tumor can be measured using (13)C magnetic resonance spectroscopy and spectroscopic imaging, and that this flux is inhibited within 24 h of chemotherapy. The reduction in the measured flux after drug treatment and the induction of tumor cell death can be explained by loss of the coenzyme NAD(H) and decreases in concentrations of lactate and enzyme in the tumors. The technique could provide a new way to assess tumor responses to treatment in the clinic. 相似文献
52.
Chopin F Orsel M Dorbe MF Chardon F Truong HN Miller AJ Krapp A Daniel-Vedele F 《The Plant cell》2007,19(5):1590-1602
In higher plants, nitrate is taken up by root cells where Arabidopsis thaliana NITRATE TRANSPORTER2.1 (ATNRT2.1) chiefly acts as the high-affinity nitrate uptake system. Nitrate taken up by the roots can then be translocated from the root to the leaves and the seeds. In this work, the function of the ATNRT2.7 gene, one of the seven members of the NRT2 family in Arabidopsis, was investigated. High expression of the gene was detected in reproductive organs and peaked in dry seeds. beta-Glucuronidase or green fluorescent protein reporter gene expression driven by the ATNRT2.7 promoter confirmed this organ specificity. We assessed the capacity of ATNRT2.7 to transport nitrate in Xenopus laevis oocytes or when it is expressed ectopically in mutant plants deficient in nitrate transport. We measured the impact of an ATNRT2.7 mutation and found no difference from the wild type during vegetative development. By contrast, seed nitrate content was affected by overexpression of ATNRT2.7 or a mutation in the gene. Finally, we showed that this nitrate transporter protein was localized to the vacuolar membrane. Our results demonstrate that ATNRT2.7 plays a specific role in nitrate accumulation in the seed. 相似文献
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Mathilde Hertz 《Journal of comparative physiology. A, Neuroethology, sensory, neural, and behavioral physiology》1934,21(3):463-467
Zusammenfassung Bienen, die mit Zuckerwasser gefüttert werden, das sie durch Drahtgaze aus einer größeren offenen Schale saugen, sind nach wenigen Stunden auf Wasser dressiert. Sie befliegen unter Drahtgaze aufgestellte Glasnäpfchen, die geringe Mengen destilliertes Wasser, Salzwasser, Zitronensaft, Milch oder feuchte Erde enthalten, während sie die gleichen Näpfchen, leer oder mit Alkohol oder Glyzerin beschickt, nicht befliegen. 相似文献
57.
Gache V Louwagie M Garin J Caudron N Lafanechere L Valiron O 《Biochemical and biophysical research communications》2005,327(1):35-42
Microtubules play an essential role in eukaryotic cells, where they perform a wide variety of functions. In this paper, we describe the characterization of proteins associated to tubulin dimer in its native form, using affinity chromatography and mass spectrometry. We used an immunoaffinity column with coupled-monoclonal antibody directed against the alpha-tubulin C-terminus. Tubulin was first loaded onto the column, then interphase and mitotic cell lysates were chromatographed. Tubulin-binding proteins were eluted using a peptide mimicking the alpha-tubulin C-terminus. Elution fractions were analyzed by SDS-PAGE, and a total of 14 proteins were identified with high confidence by mass spectrometry. These proteins could be grouped in four classes: known tubulin-binding proteins, one microtubule-associated protein, heat shock proteins, and proteins that were not shown previously to bind tubulin dimer or microtubules. 相似文献
58.
Raymond MA Désormeaux A Labelle A Soulez M Soulez G Langelier Y Pshezhetsky AV Hébert MJ 《Biochemical and biophysical research communications》2005,338(3):1374-1382
Endothelial cells (EC) under stress release paracrine mediators that facilitate accumulation of vascular smooth muscle cells (VSCM) at sites of vascular injury. We found that medium conditioned by serum-starved EC increase proliferation and migration of VSCM in vitro. Fractionation of the conditioned medium followed by mass spectral analysis identified one bioactive component as vitamin D-binding protein (DBP). DBP induced both proliferation and migration of VSMC in vitro in association with increased phosphorylation of ERK 1/2. PD 98059, a biochemical inhibitor of ERK 1/2, abrogated these proliferative and migratory responses in VSMC. DBP is an important carrier for the vitamin-D sterols, 25-hydroxyvitamin-D, and 1alpha,25-dihydroxyvitamin-D. Both sterols inhibited the activity of DBP on VSMC, suggesting that vitamin D binding sites are important for initiating the activities of DBP on VSMC. Release of DBP at sites of endothelial injury represents a novel pathway favoring accumulation of VSMC at sites of vascular injury. 相似文献
59.
Evidence of finely tuned expression of DNA polymerase beta in vivo using transgenic mice 总被引:4,自引:0,他引:4
Bergoglio V Fréchet M Philippe M Bieth A Mercier P Morello D Lacroix-Tricki M Delsol G Hoffmann JS Cazaux C 《FEBS letters》2004,566(1-3):147-150
DNA polymerase (Pol) is an error-prone repair DNA polymerase that has been shown to create genetic instability and tumorigenesis when overexpressed by only 2-fold in cells, suggesting that a rigorous regulation of its expression may be essential in vivo. To address this question, we have generated mice which express a transgene (Tg) bearing the Pol cDNA under the control of the ubiquitous promoter of the mouse H-2K gene from the major histocompatibility complex. These mice express the Tg only in thymus, an organ which normally contains the most abundant endogenous Pol mRNA and protein, supporting the idea of a tight regulation of Pol in vivo. Furthermore, we found no tumor incidence, suggesting that the single Pol overexpression event is not sufficient to initiate tumorigenesis in vivo. 相似文献
60.
Ros M Sorensen D Waagepetersen R Dupont-Nivet M SanCristobal M Bonnet JC Mallard J 《Genetics》2004,168(4):2089-2097
Phenotypic plasticity and canalization are important topics in quantitative genetics and evolution. Both concepts are related to environmental sensitivity. The latter can be modeled using a model with genetically structured environmental variance. This work reports the results of a genetic analysis of adult weight in the snail Helix aspersa. Several models of heterogeneous variance are fitted using a Bayesian, MCMC approach. Exploratory analyses using posterior predictive model checking and model comparisons based on the deviance information criterion favor a model postulating a genetically structured heterogeneous environmental variance. Our analysis provides a strong indication of a positive genetic correlation between additive genetic values affecting the mean and those affecting environmental variation of adult body weight. The possibility of manipulating environmental variance by selection is illustrated numerically using estimates of parameters derived from the snail data set. 相似文献