How do Shp2 mutations that oppositely influence its biochemical activity result in syndromes with overlapping symptoms?

Activating and inactivating mutations of SHP-2 are responsible, respectively, for the Noonan (NS) and the LEOPARD (LS) syndromes. Clinically, these developmental disorders overlap greatly, resulting in the apparent paradox of similar diseases caused by mutations that oppositely influence SHP-2 phosphatase activity. While the mechanisms remain unclear, recent functional analysis of SHP-2, along with the identification of other genes involved in NS and in other related syndromes (neurofibromatosis-1, Costello and cardio-facio-cutaneous syndromes), strongly suggest that Ras/MAPK represents the major signaling pathway deregulated by SHP-2 mutants. We discuss the idea that, with the exception of LS mutations that have been shown to exert a dominant negative effect, all disease-causing mutations involved in Ras/MAPK-mediated signaling, including SHP-2, might lead to enhanced MAPK activation. This suggests that a narrow range of MAPK signaling is required for appropriate development. We also discuss the possibility that LS mutations may not simply exhibit dominant negative activity. Received 30 November 2006; received after revision 8 February 2007; accepted 13 March 2007     

Molecular cloning and expression of interleukin Ibeta (IL-1β) from red seabream (Pagrus major)

The interleukin 1β (IL-1β) cDNA was cloned from the red seabream (Pagrus major) by homology cloning strategy. A cDNA fragment was amplified by PCR using two degenerated primers, which were designed according to the conserved regions of other known IL-1β sequences, and elongated by 3' ends and 5' ends RACE PCR to get the full length coding sequence of red seabream IL-1β (RS IL-1β). The sequence contained 1252 nucleotides that included a 5' untranslated region (UTR) of 84bp, a 3' UTR of 410 bp and an open reading frame (ORF) of 759 nucleotides which could be translated into a putative peptide of 253 amino acids with molecular weight of 28.6 kD and putative isoelectric point pI of 5.29. The deduced peptide contained two potential N-glycosylation sites and an identifiable IL1 family signature, but lacked the signal peptide and the clear ICE cut site, which were common in other nonmammalian IL-1β genes. The RS IL-1β had the highest homology with piscine IL-1β according to phylogenetic tree analysis.     

凝聚环的几个特征

证明了对于一个环R，下列条件等价：(1)R是左凝聚的；(2)对任意正整数n，Mn(R)是左1-凝聚的；(3)Ext^2R(R／I，N)=0对于任意有限生成左理想I及F-内射模RN成立；(4)若N1≤N都是F-内射左R-模，则N／N1也是F-内射模．     

电磁场问题光滑样条函数解法

利用一类二元样条函数，对任意给定区域的任意三角剖分，导出了光滑有限元方法，此方法求解二维电磁场问题，不仅可保护场域中位函数的连续性，而且可保证场量（位的导函数）的连续性，此方法与常规线性插值有限元相比，具有三角剖分数少及初始输入数据量小等优点。     

玉米两个自交系及其杂交F_1染色体G-带带型的比较

对玉米两个自交系京7和华5及其杂交F_1的染色体G-带带型进行了比较研究。结果表明,两自交系的G-带中A型带之间的相似点很多,有的完全一致;而B型带在带的数目和分布位置上有差异。杂交F_1的G-带带型具有杂合性,B型带的杂合性尤为明显。文中讨论了G-带、C-带和N-带并存等问题。     

一类新型双杂环衍生物的合成及其杀菌活性

三唑并嘧啶类杂环衍生物由于其分子结构中同时包含了三唑及嘧啶这两类重要的活性结构单元 ,因而往往表现出广泛的生物活性[1～ 4] ,既可以用于医药 ,也可以用于农药 .因此 ,近年来关于三唑并嘧啶类衍生物的合成及其生物活性的研究受到了人们的广泛关注 -二甲基 - 1 ,2 ,4-三唑     

电镀添加剂的NMR定量分析

本文叙述了用于定量分析电镀添加剂中丙烯磺酸钠和糖精钠的快速、准确、精密的ＮＭＲ分析方法．该方法是依据每个组分的ＮＭＲ特征信号和用作内标的四甲基澳化按ＮＭＲ信号的积分比值建立的，各组分不需要预先分离．     

苏云金杆菌库斯塔变种(HD-1)对菜青虫杀虫效果的研究

通过实验室饲料感染方法和大田喷杀对比试验研究，表明发酵培养基中添加花生饼可以提高HD—1的杀虫效果，且添加浓度与HD—1菌株毒力呈正相关，用添加了花生饼的固体浅盘发酵培养液比市售工业化生产的同类杀虫剂杀虫效果要高得多。     

顺式丁二烯及其一氟、一氯取代物电环化反应过程的量子化学研究

用密度泛函理论（DFT）的B3LYP方法在6－311＋＋G**基组水平上研究了cis-1,3-丁二烯及其一氟、一氯取代物电环化反应过程的微观机理，优化得到了反应途径上的反应物、过渡态和产物的几何构型，通过振动分析对过渡态进行了确认，并对优化得到的单点在QCISD（T）水平上计算了能量。研究结果表明：cis-1,3－丁二烯的氟、氯代衍生物各有两种构象，且均能发生环化反应，两种构象环化的产物是一致的；亚甲基上外侧的氢原子被氟、氯原子取代后，有利于环化反应的进行。     

三邻菲咯啉合亚钌-亚硫酸根-氯酸钾体系化学发光法测定葡萄酒中亚硫酸盐总量

提出了Ru(phen) 32 +-SO32 - -KClO3(phen =1 ,1 0菲咯啉 )体系化学发光法测定溶液中亚硫酸盐含量的方法 .SO32 - 浓度与化学发光强度在 1 .0× 1 0 - 6～ 1 .0× 1 0 - 3 mol/L范围内成正比 ,检出限为 2 .32× 1 0 - 6mol/L (S/N =3) ,1 .0× 1 0 - 4 mol/LSO32 - 溶液重复 6次测定结果的相对标准偏差为 3.8% .该方法成功地用于白葡萄酒中的亚硫酸盐总含量的测定 ,结果令人满意 .