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971.
The plant cell wall has a somewhat paradoxical mechanical role in the plant: it must be strong enough to resist the high turgor of the cell contents, but at the right moment it must yield to that pressure to allow cell growth. The control of the cell wall's mechanical properties underlies its ability to regulate growth correctly. Recently, we have reported on changes in cell wall elasticity associated with organ formation at the shoot apical meristem in Arabidopsis thaliana. These changes in cell wall elasticity were strongly correlated with changes in pectin matrix chemistry, and we have previously shown that changes in pectin chemistry can dramatically effect organ formation. These findings point to a important role of the cell wall pectin matrix in cell growth control of higher plants. In this addendum we will discuss the biological significance of these new observations, and will place the scientific advances made possible through Atomic Force Microscopy-based nano-indentations in a relatable context with past experiments on cell wall mechanics. 相似文献
972.
Biochemical and Biophysical Characterization of the Mg2+-induced 90-kDa Heat Shock Protein Oligomers
973.
Genetic heterogeneity in hypokalemic periodic paralysis (hypoPP) 总被引:7,自引:0,他引:7
Emmanuelle Plassart Alexis Elbaz Jose Vale Santos Jocelyne Reboul Pascale Lapie Dominique Chauveau Karin Jurkat-Rott Joao Guimaraes Jean-Marie Saudubray Jean Weissenbach Frank Lehmann-Horn Bertrand Fontaine 《Human genetics》1994,94(5):551-556
Hypokalemic periodic paralysis (hypoPP) is an autosomal dominant disorder belonging to a group of muscle diseases known to involve an abnormal function of ion channels. The latter includes hypokalemic and hyperkalemic periodic paralyses, and non-dystrophic myotonias. We recently showed genetic linkage of hypoPP to loci on chromosome 1q31-32, co-localized with the DHP-sensitive calcium channel CACNL1A3. We propose to term this locus hypoPP-1. Using extended haplotypes with new markers located on chromosome 1q31-32, we now report the detailed mapping of hypoPP-1 within a 7 cM interval. Two recombinants between hypoPP-1 and the flanking markers D1S413 and D1S510 should help to reduce further the hypoPP-1 interval. We used this new information to demonstrate that a large family of French origin displaying hypoPP is not genetically linked to hypoPP-1. We excluded genetic linkage over the entire hypoPP-1 interval showing for the first time genetic heterogeneity in hypoPP. 相似文献
974.
CD90 Expression on human primary cells and elimination of contaminating fibroblasts from cell cultures 总被引:1,自引:0,他引:1
Cluster Differentiation 90 (CD90) is a cell surface glycoprotein originally identified on mouse thymocytes. Although CD90
has been identified on a variety of stem cells and at varying levels in non-lymphoid tissues such as on fibroblasts, brain
cells, and activated endothelial cells, the knowledge about the levels of CD90 expression on different cell types, including
human primary cells, is limited. The goal of this study was to identify CD90 as a human primary cell biomarker and to develop
an efficient and reliable method for eliminating unwanted or contaminating fibroblasts from human primary cell cultures suitable
for research pursuant to cell based therapy technologies. 相似文献
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976.
Janis E. Lochner Leah S. Honigman Wilmon F. Grant Sarah K. Gessford Alexis B. Hansen Michael A. Silverman Bethe A. Scalettar 《Developmental neurobiology》2006,66(6):564-577
Tissue plasminogen activator (tPA) has been implicated in a variety of important cellular functions, including learning‐related synaptic plasticity and potentiating N‐methyl‐D ‐aspartate (NMDA) receptor‐dependent signaling. These findings suggest that tPA may localize to, and undergo activity‐dependent secretion from, synapses; however, conclusive data supporting these hypotheses have remained elusive. To elucidate these issues, we studied the distribution, dynamics, and depolarization‐induced secretion of tPA in hippocampal neurons, using fluorescent chimeras of tPA. We found that tPA resides in dense‐core granules (DCGs) that traffic to postsynaptic dendritic spines and that can remain in spines for extended periods. We also found that depolarization induced by high potassium levels elicits a slow, partial exocytotic release of tPA from DCGs in spines that is dependent on extracellular Ca+2 concentrations. This slow, partial release demonstrates that exocytosis occurs via a mechanism, such as fuse‐pinch‐linger, that allows partial release and reuse of DCG cargo and suggests a mechanism that hippocampal neurons may rely upon to avoid depleting tPA at active synapses. Our results also demonstrate release of tPA at a site that facilitates interaction with NMDA‐type glutamate receptors, and they provide direct confirmation of fundamental hypotheses about tPA localization and release that bear on its neuromodulatory functions, for example, in learning and memory. © 2006 Wiley Periodicals, Inc. J Neurobiol, 2006 相似文献
977.
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979.
Notch signaling modulates proliferation and differentiation of intestinal crypt base columnar stem cells 总被引:1,自引:0,他引:1
980.