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231.
Liu F Thirumangalathu S Gallant NM Yang SH Stoick-Cooper CL Reddy ST Andl T Taketo MM Dlugosz AA Moon RT Barlow LA Millar SE 《Nature genetics》2007,39(1):106-112
Fungiform taste papillae form a regular array on the dorsal tongue. Taste buds arise from papilla epithelium and, unusually for epithelial derivatives, synapse with neurons, release neurotransmitters and generate receptor and action potentials. Despite the importance of taste as one of our five senses, genetic analyses of taste papilla and bud development are lacking. We demonstrate that Wnt-beta-catenin signaling is activated in developing fungiform placodes and taste bud cells. A dominant stabilizing mutation of epithelial beta-catenin causes massive overproduction of enlarged fungiform papillae and taste buds. Likewise, genetic deletion of epithelial beta-catenin or inhibition of Wnt-beta-catenin signaling by ectopic dickkopf1 (Dkk1) blocks initiation of fungiform papilla morphogenesis. Ectopic papillae are innervated in the stabilizing beta-catenin mutant, whereas ectopic Dkk1 causes absence of lingual epithelial innervation. Thus, Wnt-beta-catenin signaling is critical for fungiform papilla and taste bud development. Altered regulation of this pathway may underlie evolutionary changes in taste papilla patterning. 相似文献
232.
Blasig IE Winkler L Lassowski B Mueller SL Zuleger N Krause E Krause G Gast K Kolbe M Piontek J 《Cellular and molecular life sciences : CMLS》2006,63(4):505-514
Tight junctions seal intercellular clefts via membrane-related strands, hence, maintaining important organ functions. We investigated
the self-association of strand-forming transmembrane tight junction proteins. The regulatory tight junction protein occludin
was differently tagged and cotransfected in eucaryotic cells. These occludins colocalized within the plasma membrane of the
same cell, coprecipitated and exhibited fluorescence resonance energy transfer. Differently tagged strand-forming claudin-5
also colocalized in the plasma membrane of the same cell and showed fluorescence resonance energy transfer. This demonstrates
self-association in intact cells both of occludin and claudin-5 in one plasma membrane. In search of dimerizing regions of
occludin, dimerization of its cytosolic C-terminal coiledcoil domain was identified. In claudin-5, the second extracellular
loop was detected as a dimer. Since the transmembrane junctional adhesion molecule also is known to dimerize, the assumption
that homodimerization of transmembrane tight junction proteins may serve as a common structural feature in tight junction
assembly is supported.
Received 6 October 2005; received after revision 14 December 2005; accepted 27 December 2005
†These authors contributed equally to this work. 相似文献
233.
Information processing along the course of a visual interneuron. 总被引:1,自引:0,他引:1
Locust ocellar retinal cells are innervated by giant second order cells, 2 mm long, which show discrete zones of integration along their course, including a major zone in the axonal length of the neuron. The complex synaptic arrangements which exist between higher-order afferent and efferent cells and these second order cells along their course suggests that transmission takes place by the electrotonic spread of slow potentials. The size and accessibility of these visual interneurons offers a unique preparation for examining mechanisms of graded synaptic transmission. 相似文献
234.
Ethanol, 3 g/kg i.p., did not significantly alter the acute toxicity of amphetamine in the mouse. However, the urinary metabolite pattern was changed, suggesting that ethanol suppressed metabolism of the stimulant during the initial 6 h period. After 24 h, the mouse metabolized the same fraction of a given dose of amphetamine, whether it was given as amphetamine alone or amphetamine mixed with 2,3 or 4 g/kg ethanol. 相似文献
235.
Relation between total and exchangeable sodium in the body 总被引:1,自引:0,他引:1
236.
吕佳萍 《南京工程学院学报(自然科学版)》2006,4(2):1-5
给出了Z[√-2]中的非零整数表示为Z[√-2]中的两整数平方差的表示种数,还给出了Z[√-2]中的非零整数表示为x^2+2y^2(其中x,y∈Z[√-2])形式的表示种数. 相似文献
237.
欧洲七叶树体细胞次生胚重复发生研究 总被引:5,自引:0,他引:5
取欧洲七叶树体细胞胚的子叶诱导次生胚发生,表明:MS ZT(0.5~2.0 mg/L) BA 1.0 mg/L IAA 0.2 mg/L培养基可直接诱导次生胚发生,诱导率超过80%;同一子叶的不同部位分化能力不同,靠近胚轴部位分化能力最强,其他部位比较弱。 相似文献
238.
量子神经计算是传统神经计算与量子计算相结合的产物,它将成为新的信息处理技术之一.文中以相移门和受控非门作为基本的计算单元,借助复数BP学习算法,构造出量子神经元模型,通过数值计算给出了该量子神经元的收敛特性曲线.在此模型基础上,构造出一个三层量子神经网络,应用于含噪字母识别.数值计算结果表明,量子神经网络在噪声均方差小于0.35之前能完全地对含噪英文字母进行识别,容错能力比传统神经网络有明显增强. 相似文献
239.
240.
基于Thomas—Fermi半经曲近似即局域密度近似和平衡态化学势为常数原理,计算了相对论q-玻色气体的热力学量,得到了玻色爱因斯坦凝聚的判据以及热容量跃变的判据,这不同于以往文献的理论结果. 相似文献