“肾脏的结构”教学设计

1学习内容分析 1）“肾脏的结构”是以形态结构知识为主的一节课。这节课名词术语比较多,内容比较枯燥,学生对于这些内容不易产生兴趣。但是这些知识又是学生理解尿液形成过程的基础,也为学习泌尿系统的卫生保健奠定基础。     

《自然－结构与分子生物学》：科学家揭示DNA解旋机理

美国斯克利普斯研究院（TSRI）的研究人员近日揭示了大分子机器如何解开细胞核内长而纠结的DNA链。这种DNA解旋极为重要,它能指导合成具有许多特定功能的蛋白。相关研究论文在线发表于11月23日的《自然－结构与分子生物学》（Nature Structural＆Molecular Biology）上。     

《肝脏学》：特殊蛋白质影响肝脏再生

近期,国际著名期刊《肝脏学》（Hepatology．2009Jan;49（1）：240-9）发表了中科院上海生科院生化与细胞所陈正军组关于Cdc42影响肝脏再生过程的最新研究成果。Cdc42蛋白是RhoGTP酶家族中的一员,它是细胞内一种十分重要的蛋白质,担负着调节细胞骨架结构、细胞生长、细胞极性以及细胞内运输等多种功能。然而目前对Cdc42在哺乳动物肝脏中的作用仍然知之甚少．陈正军组的袁海心等利用肝脏2／3切除手术模型,     

How Many 3D Structures Do We Need to Train a Predictor？

It has been shown that the progress in the determination of membrane protein structure grows exponentially, with approximately the same growth rate as that of the water-soluble proteins. In order to investigate the effect of this, on the performance of prediction algorithms for both α-helical and β-barrel membrane proteins, we conducted a prospective study based on historical records. We trained separate hidden Markov models with different sized training sets and evaluated their performance on topology pred...     

出芽短梗霉在三种不同氮源的培养基中多糖积累以及形态变化

本研究旨在阐明出芽短梗霉在不同氮源培养基中形态和胞外多糖的积累及化学成分变化。采用摇瓶法培养出芽短梗霉。三种培养基的氮源分别为硝酸钠(培养基1,M1)、硫酸氨、酵母膏(培养基2,M2)和硫酸氨、蛋白胨和酵母膏(培养基3,M3)。M1培养基中,菌丝体和单细胞的生物量积累均比M2、M3低,但胞外多糖的产量则等于甚至略超过M2和M3。在指数生长的前期,白色菌丝体和酵母状细胞状态占优势。指数生长的后期,以厚垣孢子、肿大细胞和黑色菌丝体占优势。胞外多糖都能为茁霉多糖酶水解为麦芽糖和麦芽三糖,说明这些多糖的化学组成都具有(1→4,1→6)-α结构的茁霉多糖。但M1中产生的茁霉多糖结构单元为麦芽糖和麦芽三糖,且二者比例相当。M2中茁霉多糖的麦芽糖结构单元明显减少,而M3中144h后麦芽糖结构单元完全消失。这似乎表明氧化性的氮源和低溶解氧水平可能是造成茁霉多糖结构单元同时具有麦芽糖和麦芽三糖的原因。     

Characterization of the putative tryptophan synthase β-subunit from Mycobacterium tuberculosis

The increasing emergence of drug-resistant tuberculosis （TB） poses a serious threat to the control of this disease. It is in urgent need to develop new TB drugs. Tryptophan biosynthetic pathway plays an important role in the growth and replication of Mycobacterium tuberculosis （Mtb）. The β-subunit of tryptophan synthase （TrpB） catalyzes the last step of the tryptophan biosynthetic pathway, and it might be a potential target for TB drug design. In this study, we overexpressed, purified, and characterized the putative TrpB-encoding gene Rv1612 in Mtb H37Rv. Results showed that Mtb His-TrpB optimal enzymatic activity is at pH 7.8 with 0.15 M Na^＋ or 0.18 M Mg^2＋ at 37℃. Structure analysis indicated that Mtb TrpB exhibited a typical β/α barrel structure. The amino acid residues believed to interact with the enzyme cofactor pyridoxal-5＇-phosphate were predicted by homology modeling and structure alignment. The role of these residues in catalytic activity of the Mtb His-TrpB was confirmed by site-directed mutagenesis. These results provided reassuring structural information for drug design based on TrpB.     

Doppel-induced cytotoxicity in human neuronal SH-SY5Y cells is antagonized by the prion protein

Doppel （Dpl） is a prion （PrP）-like protein due to the structural and biochemical similarities; however, the natural functions of Dpl and PrP remain unclear. In this study, a 531-bp human PRND gene sequence encoding Dpl protein was amplified from human peripheral blood leucocytes. Furl-length and various truncated human Dpl and PrP proteins were expressed and purified from Escherichia coil Supplement of the full-length Dpl onto human neuroblastoma cell SH-SY5Y induced remarkable cytotoxicity, and the region responsible for its cytotoxicity was mapped at the middle segment of Dpl [amino acids （aa） 81-122]. Interestingly, DpMnduced cytotoxicity was antagonized by the presence of full- length wild-type PrP. Analysis on fragments of PrP mutants showed that the N-terminal fragment （aa 23- 90） of PrP was responsible for the protective activity. A truncated PrP （PrPA32-121） with similar secondary structure as Dpl induced DpMike cytotoxicity on SH- SY5Y cells. Furthermore, binding of copper ion could enhance the antagonizing effect of PrP on Dpi-induced cytotoxicity. Apoptosis assays revealed that cytotoxicity induced by Dpl occurred through an apoptotic mechanism. These results suggested that the function of Dpl is antagonistic to PrP rather than synergistic.     

The structure-function relationship of MSI7, a matrix protein from pearl oyster Pinctada fucata

We previously identified a matrix protein, MSI7, from pearl oyster Pinctada fucata. According to the structural analysis, the DGD site in the N-terminal of MSI7 is crucial for its role in the shell formation. In this study, we expressed a series of recombinant MSI7 proteins, including the wild-type and several mutants directed at the DGD site, using an Escherichia coli expression system to reveal the structure-function relationship of MSI7. Furthermore, in vitro crystallization, crystallization speed assay, and circular dichroism spectrometry were carried out. Results indicated that wild-type MSI7 could induce the nucleation of aragonite and inhibit the crystallization of calcite. However, none of the mutants could induce the nucleation of aragonite, but all of them could inhibit the crystallization of calcite to some extent. And all the proteins accelerated the crystallization process. Taken together, the results indicated that MSI7 could contribute to aragonite crystallization by inducing the nucleation of aragonite and inhibiting the crystallization of calcite, which agrees with our prediction about its role in the nacreous layer formation of the shell. The DGD site was critical for the induction of the nucleation of aragonite.     

慢性肾脏病患者心脏结构与功能变化的超声心动图研究

目的:研究慢性肾脏病(CKD)患者心脏结构及功能的变化.方法:选择我院肾内科175例慢性肾脏病未透析患者,按照2003年美国国家肾脏基金会-肾脏病转归质量(NKF-K/DOQI)指南的标准进行分期,观察所有患者心脏结构及功能在超声中的变化.结果:慢性肾脏病患者随着肾功能的恶化,各组之间比较,室间隔厚度(IVST)、左心室后壁厚度(LVPW)、左心室心肌重量指数(LVMI)、左心室舒张末期内径(LVDd)、左心房内径(LAD)具有升高的趋势(P＜0.05,P＜0.01);但E/A比值未出现伴随着肾功能恶化而逐渐减低的趋势(P＞0.05);射血分数(EF)、短轴缩短卒(FS)在各期之间无明显变化(P＞0.05);而TVI技术测定的Em、Em/Am具有显著减低的趋势(P＜0.05,P＜0.01);瓣膜返流以二尖瓣返流为主.结论:慢性肾脏病患者心脏结构与功能随肾功能减退而加重,超声心动图检查结合组织速度显像(TVI)技术能更好地检测心脏结构和功能变化,尤其是检测左心室舒张功能障碍.     

竹维素微粉的结构与性能研究

采用热化学酚化技术分离得到竹纤维素微粉(BCMP).通过对比实验.分析测试了竹纤维酚化前后的结构和性能.实验结果表明,BCMP纤维含量达92%以上,粒径(长度方向)为20～200μm,羟值80～190 mgKOH/g,热分解温度达300℃以上,具有比竹粉更好的疏水性,耐热性,仍保持竹纤维的部分结晶结构;抗老化实验和抗菌实验结果也表明竹纤维素微粉具有比竹粉/木粉更好的抗紫外吸收性能,对细菌繁殖具有显著的抑制作用.