PDGF induces osteoprotegerin expression in vascular smooth muscle cells by multiple signal pathways

Acetohydroxyacid synthase (AHAS; EC 4.1.3.18) contains catalytic and regulatory subunits, the latter being required for sensitivity to feedback regulation by leucine, valine and isoleucine. The regulatory subunit of Arabidopsis thaliana AHAS possesses a sequence repeat and we have suggested previously that one repeat binds leucine while the second binds valine or isoleucine, with synergy between the two sites. We have mutated four residues in each repeat, based on a model of the regulatory subunit. The data confirm that there are separate leucine and valine/isoleucine sites, and suggest a complex pathway for regulatory signal transmission to the catalytic subunit.     

Specific targeting of nasopharyngeal carcinoma cell line CNE1 by C225-conjugated ultrasmall superparamagnetic iron oxide particles with magnetic resonance imaging

An accurate definition of clinical target volume (CTV) is essential for the application of radiotherapy in nasopharyngeal carcinoma (NPC) treatment. A novel epidermal growth factor receptor (EGFR)-targeting contrast agent (C225-USPIO) was designed by conjugating ultrasmall superparamagnetic iron oxide (USPIO) nanoparticles with cetuximab (C225), to non-invasively define the CTV of tumor. The immunobinding activity of C225-USPIO to NPC cell line CNE1 was confirmed by flow cytometry and immunofluorescence. The time-dependent accumulation of C225-USPIO in CNE1 cells was evaluated using Prussian blue staining. Targeted internalization and subcellular localization of C225-USPIO was confirmed by transmission electron microscope. The results indicated that C225-USPIO specifically bound to EGFR on the surface of CNE1 cells and was taken up into the cell. The uptake of C225-USPIO by CNE1 cells increased significantly with time, when compared with human IgG-USPIO. In addition, 4.7 T magnetic resonance imaging (MRI) revealed that C225-USPIO had a capacity to accumulate in the CNE1 cells, with a resultant marked decrease in MRI T2-weighted signal intensity over time. These findings imply that C225-USPIO has the potential as an MRI contrast agent and can be employed to non-invasively detect early-stage NPC with EGFR overexpression. This provides sufficient theoretical basis for commencing in vivo experiments with the compound.     

东乡野生稻根际可培养细菌多样性及其植物促生活性分析

为了解江西东乡野生稻(Oryza rufipogon)不同生育期根际可培养细菌群落多样性动态,从中寻找新的具有植物促生活性的微生物资源,分别于2009年5月、8月和11月采集了东乡野生稻秧苗期、抽穗期和成熟期根际土壤,采用稀释平板法分离到118株根际细菌,并检测了其植物促生活性.16S rRNA基因序列分析结合菌体形态...     

褶纹冠蚌珍珠囊发育的研究

以褶纹冠蚌(Cristaria plicata Leach)为实验对象,应用光学显微技术和扫描电子显微技术研究珍珠囊的发育,结果表明在水温16℃左右时约需30d形成具有单层上皮细胞的珍珠囊,6个月后稳定分泌珍珠质。构成珍珠囊的上皮细胞从高柱状逐渐变成扁平状或立方形,细胞的碳酸酐酶污性也日益增强。大部分移植细胞小片的结缔组织与母蚌的结缔组织共同成层排列在珍珠囊腔外围。游走细胞在珍珠囊的早期发育阶段十分活跃。本文还阐明了珍珠囊液是存在于上皮细胞与珍珠表面之间的一薄层流体状物质。碳酸钙结晶的核化(nucleation)和初期生长都发生在珍珠囊液中。     

华北地区汉族的Lewis、ABO、MN、Rh、P等血型系统和ABH分泌型的分布

调查了原籍华北地区汉族的ABO、Lewis、MN、Rh、P等血型系统和ABH分泌型的分布,结果表明:O型(33.44％)和B型(29.38％)较多;N型(27.97％)略多于M型(27.65％);Le(a )型的频率很高(24.17％)。在94人中还发现四名Le(a )型属于ABH分泌型,且都属于分泌A或B血型物质的类型,无一例为分泌H血型物质的类型;Rh(D)阴性率仅0.3％,CCDee和CcDE型占75％以上;P_1( )型占39.1％;ABH分泌型占72％,低于全国其他民族中已知的分布。     

温度对感染沃尔巴克氏体的松毛虫赤眼蜂种群参数的影响

在16℃、20℃、24℃、28℃和32℃恒温下,观察了温度对感染沃尔巴克氏体的松毛虫赤眼蜂发育、存活和繁殖的影响,组建了相应温度下的实验种群生命表。结果表明,在实验温度范围内,感染沃尔巴克氏体的松毛虫赤眼蜂的发育历期随着温度的升高而逐渐缩短,5个温度下感染沃尔巴克氏体的松毛虫赤眼蜂世代的发育历期分别为23.2、17.8、13.2、11.1和7.8天,世代的发育起点温度和有效积温分别为7.40℃和212.69日·度,内禀增长率(r_m)和净生殖力(R₀)分别介于0.2448～0.4584和28.00～84.03之间。结果提示温度24℃～28℃为繁殖感染沃尔巴克氏体的松毛虫赤眼蜂的理想温度条件。