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261.
Chauvière M Kress C Kress M 《Biochemical and biophysical research communications》2008,372(4):513-519
Eg5, a member of the widely conserved kinesin-5 family, is a plus-end-directed motor involved in separation of centrosomes, and in bipolar spindle formation and maintenance during mitosis in vertebrates. To investigate the requirement for Eg5 in mammalian development, we have generated Eg5 deficient mice by gene targeting. Heterozygous mice are healthy, fertile, and show no detectable phenotype, whereas Eg5−/− embryos die during early embryogenesis, prior to the implantation stage. This result shows that Eg5 is essential during early mouse development and cannot be compensated by another molecular motor. 相似文献
262.
Extracellular export of sphingosine kinase-1 enzyme. Sphingosine 1-phosphate generation and the induction of angiogenic vascular maturation. 总被引:13,自引:0,他引:13
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Daniel C Hatton Qi Yue Jacqueline Dierickx Chantal Roullet Keiichi Otsuka Mitsuaki Watanabe Sarah Coste Jean Baptiste Roullet Thongchan Phanouvang Eric Orwoll Shiela Orwoll David A McCarron 《Journal of applied physiology》2002,92(1):3-12
To determine the influence of dietary calcium on spaceflight-induced alterations in calcium metabolism and blood pressure (BP), 9-wk-old spontaneously hypertensive rats, fed either high- (2%) or low-calcium (0.02%) diets, were flown on an 18-day shuttle flight. On landing, flight animals had increased ionized calcium (P < 0.001), elevated parathyroid hormone levels (P < 0.001), reduced calcitonin levels (P < 0.05), unchanged 1,25(OH)(2)D(3) levels, and elevated skull (P < 0.01) and reduced femur bone mineral density. Basal and thrombin-stimulated platelet free calcium (intracellular calcium concentration) were also reduced (P < 0.05). There was a tendency for indirect systolic BP to be reduced in conscious flight animals (P = 0.057). However, mean arterial pressure was elevated (P < 0.001) after anesthesia. Dietary calcium altered all aspects of calcium metabolism (P < 0.001), as well as BP (P < 0.001), but the only interaction with flight was a relatively greater increase in ionized calcium in flight animals fed low- compared with high-calcium diets (P < 0.05). The results indicate that 1) flight-induced disruptions of calcium metabolism are relatively impervious to dietary calcium in the short term, 2) increased ionized calcium did not normalize low-calcium-induced elevations of BP, and 3) parathyroid hormone was paradoxically increased in the high-calcium-fed flight animals after landing. 相似文献
265.
Françoise Corbineau Chantal Gay-Mathieu Dominique Vinel Daniel Côme 《Physiologia plantarum》2002,116(4):489-496
The aim of the present work was to investigate whether loss of germination ability and viability of sunflower (Helianthus annuus L.) seeds during incubation at a high temperature (45°C) was related to changes in energy metabolism, loss of membrane integrity, and/or changes in lipid composition. Pre‐treatment of seeds at 45°C progressively reduced subsequent germination at the optimal temperature (25°C). Seeds did not germinate at 45°C and almost all of them were dead after 72 h of soaking at this high temperature. This loss of seed viability was associated with a large increase in leakage of K+ and total electrolytes into the incubation medium, and with production of malondialdehyde in the embryonic axis and cotyledons, suggesting a loss of membrane integrity probably due to lipid peroxidation. ATP and ADP levels increased sharply during the first hours of imbibition at 45°C, remained high for about 24 h and then decreased. As a consequence, the energy charge followed a similar pattern. If the treatment at 45°C did not exceed 48 h, seeds recovered an apparently normal energy metabolism after transfer to 25°C, even though they lost their ability to germinate at this temperature. Therefore, energy metabolism at the whole embryo level cannot be considered as an indicator of germination ability. Incubation of seeds at 45°C resulted in an increase in triacylglycerols and diacylglycerols without a significant change in their fatty acid composition. It also induced a slight increase in phospholipid content with an increase in C16:0, C18:0 and C18:1, but with no change in C18:2. In phospholipids, the C18:2/C18:1 and (C18:1 + C18:2)/ (C16:0 + C18:0) ratios thus declined during treatment at 45°C. The results obtained suggest that deterioration of sunflower seeds during incubation at a high temperature is mainly related to membrane damage and alteration of energy metabolism, and that accumulation of malondialdehyde, which is an index of lipid peroxidation, does not correspond to a decrease in total lipids and phospholipids nor to a significant change in fatty acid composition, except in PL in which the C18:2/C18:1 and (C18:1 + C18:2)/ (C16:0 + C18:0) ratios slightly declined. 相似文献
266.
Allan S. Hoffman Patrick S. Stayton Oliver Press Niren Murthy Chantal A. Lackey Charles Cheung Fiona Black Jean Campbell Nelson Fausto Themis R. Kyriakides Paul Bornstein 《Biotechnology and Bioprocess Engineering》2001,6(4):205-212
One of the important characteristics of biological systems is their ability to change important properties in response to
small environmental signals. The molecular mechanisms that biological molecules utilize to sense and respond provide interesting
models for the development of “smart” polymeric biomaterials with biomimetic properties. An important example of this is the
protein coat of viruses, which contains peptide units that facilitate the trafficking of the virus into the cell via endocytosis,
then out of the endosome into the cytoplasm, and from there into the nucleus. We have designed a family of synthetic polymers
whose compositions have been designed to mimic specific peptides on viral coats that facilitate endosomal escape. Our biomimetic
polymers are responsive to the lowered pH within endosomes, leading to disruption of the endosomal membrane and release of
important biomolecular drugs such as DNA, RNA, peptides and proteins to the cytoplasm before they are trafficked to lysosomes
and degraded by lysosomal enzymes. In this article, we review our work on the design, synthesis and action of such smart,
pH-sensitive polymers. 相似文献
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268.
Chantal Bertholom 《Option/Bio》2019,29(595-596):20
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270.
Zhijiang Yan Mathieu Delannoy Chen Ling Danielle Daee Fekret Osman Parameswary A. Muniandy Xi Shen Anneke B. Oostra Hansen Du Jurgen Steltenpool Ti Lin Beatrice Schuster Chantal Décaillet Andrzej Stasiak Alicja Z. Stasiak Stacie Stone Maureen E. Hoatlin Detlev Schindler Christopher L. Woodcock Hans Joenje Weidong Wang 《Molecular cell》2010,37(6):865-878