益智的组织培养与快速繁殖

1植物名称益智(Alpinia oxyphylla). 2材料类别笋芽. 3培养条件愈伤组织诱导及增殖培养基:(1)MS 6-BA 3.0 mg·L-1(单位下同);(2)MS 6-BA 3.0 NAA0.05;(3)MS 6-BA 3.0 NAA 0.1;(4)MS 6-BA 3.0 NAA02.不定芽分化及增殖培养基:(5)MS 6-BA1.0NAA 0.01;(6)MS 6-BA 4.0 NAA 0.1;(7)MS 6-BA 6.0 NAA 0.1;(8)MS 6-BA 8.0 NAA 0.1.生根培养基:(9)1/2MS NAA 0.2.以上培养基均添加30 g·L-1蔗糖、5.8 g·L-1卡拉胶,pH 6.0.培养温度26～28℃,光照时间8～10 h·d-1,光照度1 500～2000 lx.     

Functional properties of two mutants of human glucose 6-phosphate dehydrogenase, R393G and R393H, corresponding to the clinical variants G6PD Wisconsin and Nashville

Two severe Class I human glucose-6-phosphate dehydrogenase (G6PD, EC1.1.1.49) mutations, G6PD(Wisconsin) (nt1177 C-->G, R393G) and G6PD(Nashville) (nt1178 G-->A, R393H), affect the same codon, altering a residue in the dimer interface close to the "structural" NADP+ site. These mutations are predicted to influence interaction with the bound "structural" NADP+, long supposed to be crucial for enzyme stability. Recombinant proteins corresponding to these mutants have been constructed, expressed and purified to homogeneity. Steady-state kinetic parameters of the mutant enzymes were comparable to those of normal human G6PD, indicating that the mutations do not alter catalytic efficiency drastically. However, investigations of thermostability, urea denaturation, protease digestion, and hydrophobic exposure demonstrated that G6PD R393H is less stable than normal G6PD or R393G, and stability was more NADP+-dependent. Apoenzymes were prepared by removal of "structural" NADP+. Again the G6PD(Nashville) protein was markedly less stable, and its dissociation constant for "structural" NADP+ is approximately 500 nM, about 10 times higher than values for R393G (53 nM) and normal G6PD (37 nM). These results, together with structural information, suggest that the instability of the R393H protein, enhanced by the weakened binding of "structural" NADP+, is the likely cause of the severe clinical manifestation observed for G6PD(Nashville). They do not, however, explain the basis of disease in the case of G6PD(Wisconsin).     

Discovery of orally active pyrrolopyridine- and aminopyridine-based Met kinase inhibitors

A series of acylurea analogs derived from pyrrolopyridine and aminopyridine scaffolds were identified as potent inhibitors of Met kinase activity. The SAR at various positions of the two kinase scaffolds was investigated. These studies led to the discovery of compounds 3b and 20b, which demonstrated favorable pharmacokinetic properties in mice and significant antitumor activity in a human gastric carcinoma xenograft model.     

What is the role of the second “structural” NADP+‐binding site in human glucose 6‐phosphate dehydrogenase?

Human glucose 6-phosphate dehydrogenase, purified after overexpression in E. coli, was shown to contain one molecule/subunit of acid-extractable "structural" NADP+ and no NADPH. This tightly bound NADP+ was reduced by G6P, presumably following migration to the catalytic site. Gel-filtration yielded apoenzyme, devoid of bound NADP+ but, surprisingly, still fully active. Mr of the main component of "stripped" enzyme by gel filtration was approximately 100,000, suggesting a dimeric apoenzyme (subunit Mr = 59,000). Holoenzyme also contained tetramer molecules and, at high protein concentration, a dynamic equilibrium gave an apparent intermediate Mr of 150 kDa. Fluorescence titration of the stripped enzyme gave the K d for structural NADP+ as 37 nM, 200-fold lower than for "catalytic" NADP+. Structural NADP+ quenches 91% of protein fluorescence. At 37 degrees C, stripped enzyme, much less stable than holoenzyme, inactivated irreversibly within 2 d. Inactivation at 4 degrees C was partially reversed at room temperature, especially with added NADP+. Apoenzyme was immediately active, without any visible lag, in rapid-reaction studies. Human G6PD thus forms active dimer without structural NADP+. Apparently, the true role of the second, tightly bound NADP+ is to secure long-term stability. This fits the clinical pattern, G6PD deficiency affecting the long-lived non-nucleate erythrocyte. The Kd values for two class I mutants, G488S and G488V, were 273 nM and 480 nM, respectively (seven- and 13-fold elevated), matching the structural prediction of weakened structural NADP+ binding, which would explain decreased stability and consequent disease. Preparation of native apoenzyme and measurement of Kd constant for structural NADP+ will now allow quantitative assessment of this defect in clinical G6PD mutations.     

大口鲶ob基因的克隆及其在毕赤酵母中的表达

1994年Zhang等人利用定位克隆技术首次成功地克隆出小鼠肥胖基因(obese gene,ob基因)及人类同源序列后[1],其他动物如鸡、鸭、猪等的肥胖基因结构和部分功能相继得到了报道,但关于鱼类ob基因的结构和功能研究报道较少.     

Monoclonal antibody therapeutics with up to five specificities: Functional enhancement through fusion of target-specific peptides

The recognition that few human diseases are thoroughly addressed by mono-specific, monoclonal antibodies (mAbs) continues to drive the development of antibody therapeutics with additional specificities and enhanced activity. Historically, efforts to engineer additional antigen recognition into molecules have relied predominantly on the reformatting of immunoglobulin domains. In this report we describe a series of fully functional mAbs to which additional specificities have been imparted through the recombinant fusion of relatively short polypeptides sequences. The sequences are selected for binding to a particular target from combinatorial libraries that express linear, disulfide-constrained, or domain-based structures. The potential for fusion of peptides to the N- and C- termini of both the heavy and light chains affords the bivalent expression of up to four different peptides. The resulting molecules, called zybodies, can gain up to four additional specificities, while retaining the original functionality and specificity of the scaffold antibody. We explore the use of two clinically significant oncology antibodies, trastuzumab and cetuximab, as zybody scaffolds and demonstrate functional enhancements in each case. The affect of fusion position on both peptide and scaffold function is explored, and penta-specific zybodies are demonstrated to simultaneously engage five targets (ErbB2, EGFR, IGF-1R, Ang2 and integrin αvβ3). Bispecific, trastuzumab-based zybodies targeting ErbB2 and Ang2 are shown to exhibit superior efficacy to trastuzumab in an angiogenesis-dependent xenograft tumor model. A cetuximab-based bispecific zybody that targeting EGFR and ErbB3 simultaneously disrupted multiple intracellular signaling pathways; inhibited tumor cell proliferation; and showed efficacy superior to that of cetuximab in a xenograft tumor model.     

Effects of plant intraspecific variation on the prediction of C3/C4 vegetation ratio from carbon isotope composition of topsoil organic matter across grasslands

植物种内变异对草地表层有机质碳同位素组成预测C₃/C₄植被比的影响植物群落中C₃和C₄植物的比例和组成对诸多生态系统过程具有重要影响。解析C₃和C₄植物碳同位素的环境驱动过程与调控因子,对于从土壤碳同位素的角度来预测C₃/C₄植被比和组成具有重要意义。本研究旨在评估草原植物碳同位素特征的种内变异将如何影响C₃和C₄植物的碳同位素组成以及C₃/C₄植被比的预测。沿中国北方草原的自然干旱梯度选择26个植物群落,通过分析植物和土壤的碳同位素组成,采用混合模型来预测C₄植物对土壤有机碳的相对贡献。本研究对比分析了如下3种情境：(1)考虑C₃和C₄植物碳同位素的种内和种间效应;(2)仅考虑碳同位素的种间变异;(3)忽略碳同位素的种内和种间变异。研究结果表明,植物碳同位素组成沿中国北方草原自然干旱梯度的变化具有物种特异性。C₃和C₄植物的碳同位素组成与干旱指数之间呈显著负相关关系,但C₃植物比C₄植物对环境的干旱变化更为敏感。植物碳同位素特征的种内变异在驱动C₃植物功能群碳同位素沿干旱梯度的分布格局中发挥着重要作用。如果忽略植物碳同位素特征的种内变异将会显著高估C₄植物的相对贡献。本研究结果表明,草原植物碳同位素特征的种内变异对于准确预测C₃/C₄植被组成具有重要意义。     

形目鱼类连体胚胎两例

报道了鳉形目鱼类食蚊鱼(Gambusia affinis)和青鳉(Oryzias latipes)的连体胚胎现象各一例.上述连体胚胎均为腹部粘连,内脏各器官分别独立,产出或孵化后短时存活.     

黑胸散白蚁多对脱翅成虫群养的产卵及孵化行为

采用室内多对脱翅成虫群养的方法对黑胸散白蚁群Reticulitermes chinensis Snyder体产卵及孵化行为进行观察。结果表明:多对脱翅成虫群养,黑胸散白蚁表现出群居行为,会共同产卵、护卵;1～5对脱翅成虫群养的产卵历期分别为9.00,8.25,8.17,7.33,7.13d;孵化历期分别为36.67,39.33,31.33,35.88,36.33d;经分析差异均不显著。在1～4对脱翅成虫群养范围内,群体产卵成功率随原始脱翅成虫配对数量的增加而升高;4～5对产卵成功率比1～2对的显著要高(P<0.05)。     

四川新白蚁属一新种记述(等翅目,木白蚁科)

记述新白蚁属1新种,屏山新白蚁 Neotermes Pingshanensis sp．nov．,新种与长颚新白蚁 Neotermes dolichognathus Xu et Han相近,但体色不同,头长/宽比例不同,触角第2节明显长于第3节,左上颚缘齿4枚,前胸背板前缘具深凹.危害物为潮湿木窗框.模式标本保存于成都市白蚁防治研究所.