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921.
Inhaled allergens from house dust, mites or animal danders activate human complement in vitro by engaging the C1-component
through a non-antibody-dependent mechanism. These earlier findings are extended by showing that the allergenic components
in extracts of Parietaria pollen are almost equally potent complement activators as those from house dust or mites. Spectroscopic evidence indicates
that haemolytic complement consumption by the Parietaria allergens and their enzymic fragments is most likely related to post-translational side-chains comprising flavonoid derivatives.
These adsorbed and/or peptide-bound tannin-like structures may also explain the exceptional stability of the high- and low-molecular
mass allergenic components in Parietaria pollen extracts.
Received 12 November 1996; received after revision 12 December 1996; accepted 17 December 1996 相似文献
922.
Rotation in Correspondence Analysis 总被引:1,自引:1,他引:0
In correspondence analysis rows and columns of a nonnegative data matrix are
depicted as points in a, usually, two-dimensional plot. Although such a two-dimensional
plot often provides a reasonable approximation, the situation can occur that an approximation
of higher dimensionality is required. This is especially the case when the data
matrix is large. In such instances it may become difficult to interpret the solution. Similar
to what is done in principal component analysis and factor analysis the correspondence
analysis solution can be rotated to increase the interpretability. However, due to the various
scaling options encountered in correspondence analysis, there are several alternative
options for rotating the solutions. In this paper we consider two options for rotation in
correspondence analysis. An example is provided so that the benefits of rotation become
apparent. 相似文献
923.
在对割煤工序和放煤工序详细分析的基础上,提出了通过优化采煤机割煤速度实现优化综放采场采放工艺参数的新方法.认为采煤机合理切割速度是联系综放采场各工序的桥梁,只要输入煤层条件与装备条件,便可确定最优工艺参数,优化结果充分体现了主观因素与客观条件的有机统一.通过对兖矿集团兴隆庄煤矿5318综放面工艺参数优化,实现了日产平均1.2万t,年产426万t的全国高产高效生产水平.图3,表2,参5. 相似文献
924.
报道了《河南植物志》中未记录的河南产伞形科植物Ⅰ属(Tongoloα)、6种和4变种,其中秦岭当归(Angelicα tsinlingensis)为河南分布新记录,订正了一些分类群的学名。 相似文献
925.
926.
计算了VLHC条件下 p p碰撞在 2 0 0TeV质心系能量下的SUSY中性Higgs玻色子A0 ,h0 ,H0的光生截面 .结果表明此条件下Higgs玻色子可能被观测到 . 相似文献
927.
A. Mate M.A. de la Hermosa A. Barfull J.M. Planas C.M. Vázquez 《Cellular and molecular life sciences : CMLS》2001,58(12-13):1961-1967
D-fructose transport was characterized in renal brush-border membrane vesicles (BBMVs) from both spontaneously hypertensive rats (SHR) and normotensive genetic control Wistar-Kyoto (WKY) rats. Kinetic studies indicated that the maximal rate (Vmax) of D-fructose transport was significantly lower in SHR compared with WKY rats. No differences were observed in the Michaelis constant (Km) or the diffusion constant (Kd) between the two groups of animals. D-fructose inhibited its own transport, whereas the presence of D-glucose, D-galactose, phlorizin, and cytochalasin B did not inhibit the transport of D-fructose in either animal group. To explain the reduction in D-fructose transport in SHR, the density of the D-fructose transporter, GLUT5, was analyzed by Western blot. GLUT5 levels were lower in SHR, a reduction similar to that of the Vmax. Thus, there appears to be a high-affinity, low-capacity, GLUT5-type fructose carrier in the apical membranes of rat kidney cortex, and the decrease in the Vmax of D-fructose transport in renal BBMVs from hypertensive rats correlates well with a reduction in the expression of GLUT5 protein. 相似文献
928.
入世使中国零售业遭受巨大的冲击,文章从四个方面分析我国零售业所影响,并提出相应策略来对付国际零售业市场的竞争。 相似文献
929.
Several 4-(aminomethylisoxazolyl)-1,2-naphthoquinones inhibited growth and DNA synthesis in Trypanosoma cruzi and stimulated O2 uptake and O2-. generation by the parasite epimastigotes and their mitochondrial and microsomal membranes; these results support the idea that oxygen radicals play a role in quinone toxicity. Maximal effects on respiration and O2-. generation were observed with antimycin-inhibited cells. Similar results as well as stimulation of H2O2 production were obtained with Crithidia fasciculata despite the presence of catalase in this organism. 相似文献
930.
Tetanus and botulinum-B neurotoxins block neurotransmitter release by proteolytic cleavage of synaptobrevin. 总被引:90,自引:0,他引:90
G Schiavo F Benfenati B Poulain O Rossetto P Polverino de Laureto B R DasGupta C Montecucco 《Nature》1992,359(6398):832-835
Clostridial neurotoxins, including tetanus toxin and the seven serotypes of botulinum toxin (A-G), are produced as single chains and cleaved to generate toxins with two chains joined by a single disulphide bond (Fig. 1). The heavy chain (M(r) 100,000 (100K)) is responsible for specific binding to neuronal cells and cell penetration of the light chain (50K), which blocks neurotransmitter release. Several lines of evidence have recently suggested that clostridial neurotoxins could be zinc endopeptidases. Here we show that tetanus and botulinum toxins serotype B are zinc endopeptidases, the activation of which requires reduction of the interchain disulphide bond. The protease activity is localized on the light chain and is specific for synaptobrevin, an integral membrane protein of small synaptic vesicles. The rat synaptobrevin-2 isoform is cleaved by both neurotoxins at the same single site, the peptide bond Gln 76-Phe 77, but the isoform synaptobrevin-1, which has a valine at the corresponding position, is not cleaved. The blocking of neurotransmitter release of Aplysia neurons injected with tetanus toxin or botulinum toxins serotype B is substantially delayed by peptides containing the synaptobrevin-2 cleavage site. These results indicate that tetanus and botulinum B neurotoxins block neurotransmitter release by cleaving synaptobrevin-2, a protein that, on the basis of our results, seems to play a key part in neurotransmitter release. 相似文献