家兔在发育过程中外侧腓肠肌内MyHCs变化与诱发电位的关系

 为研究在生后不同年龄组家兔外侧腓肠肌各亚体肌纤维MyHCs变化与诱发电位的关系,探讨生后发育期间肌纤维MyHCs组成和作用差异与表型之间的相关联系,采用电生理记录仪结合十二烷基硫酸钠-聚丙烯酰胺凝胶电泳（SDS PAGE）检测外侧腓肠肌各亚体。结果表明中间亚体在刺激时各年龄组的峰值电压基本相同,而外侧亚体和内侧亚体分别有些变化。同时发现成年家兔的持续时间都较幼年的长,这可能与各亚体的肌纤维型构成比例有很大关系。外侧腓肠肌各亚体的肌球蛋白重链异构体（MyHCs）电泳条带分别显示MyHCsⅡa、Ⅱd（或Ⅱx）、Ⅱb、Ⅰ共4种,对应于骨骼肌纤维表型ⅡA型（FOG型）、ⅡX（FO型）、ⅡB型（FG型）及Ⅰ型（SO型）4类。     

Regulation of mitochondrial aconitase by phosphorylation in diabetic rat heart

Mitochondrial dysfunction and protein kinase C (PKC) activation are consistently found in diabetic cardiomyopathy but their relationship remains unclear. This study identified mitochondrial aconitase as a downstream target of PKC activation using immunoblotting and mass spectrometry, and then characterized phosphorylation-induced changes in its activity in hearts from type 1 diabetic rats. PKCβ₂ co-immunoprecipitated with phosphorylated aconitase from mitochondria isolated from diabetic hearts. Augmented phosphorylation of mitochondrial aconitase in diabetic hearts was found to be associated with an increase in its reverse activity (isocitrate to aconitate), while the rate of the forward activity was unchanged. Similar results were obtained on phosphorylation of mitochondrial aconitase by PKCβ₂ in vitro. These results demonstrate the regulation of mitochondrial aconitase activity by PKC-dependent phosphorylation. This may influence the activity of the tricarboxylic acid cycle, and contribute to impaired mitochondrial function and energy metabolism in diabetic hearts. Received 31 October 2008; received after revision 17 December 2008; accepted 2 January 2009     

标准模型下无对运算的公钥证书加密体制

为抵抗CL-PKE加密体制中因置换用户公钥产生的拒绝解密(denial of decryption)攻击,构建了一个没有使用椭圆曲线上双线性对运算的加密算法.该体制的安全模型选用了安全性较高的标准模型.此外该体制不但可以抵制外部攻击者的拒绝解密攻击,而且可以抵制密钥生成中心(KGC)的拒绝解密攻击.在提高性能的同时,还保持了较高的计算效率.     

Changes of levels of glutamine synthetase isoforms in roots and leaves in response to nitrogen fertilizer application at different growth stages in irrigated rice

Nitrogen is a key element to control the growth and yield of crops. Fertilizer urea nitrogen (N) 60,45, and 30 kg/hm² was applied at three different stages, midtillering, panicle initiation, and flowering, of the growth and development of rice plants, respectively. At both midtillering and panicle initiation, the total activity of glutamine synthetase (GS) in rice roots and leaves was incrased remarkably as a result of a large amount of ammonia absorbed by roots. Native-PAGE and activity staining showed that the increase of total activity in rice roots and leaves was due to the synthesis of GSrb in roots and GS2 in leaves and that the activity of GSra in roots and GS1 in leaves remained constant. The results showed that the assimilation of external nitrogen was carried out by GSrb but not GSra in rice roots and that the activitry of GS2 was induced also by the external nitrogen, and that GSrb played main role in meeting the needs of the rapid tillering for nitrogen. At flowering, the activity of GS in rice roots and leaves did not change almost after topdressing. These rssults suggest that the change of GS activity in rice roots may use as a measure of the utilization efficiency of the fertilizer. Supported by the National Natural Science Foundation of China, Natural Science Foundation of Hubei Province, and International Rice Institute, P. O. Box 933 1099 Manila, Philippines Zhang Chufu: born in 1946, Professor, to whom Correspondence should be addressed     

Effect of PKC pathway on G1/S progression control in HeLa cells

The effect of PKC activity on G1/S progression in HeLa cells has been studied.The result shows that (ⅰ) PKC activity alteration in G1 phase affects G1/S progression in HeLa cells.It has been observed that G1/S progression is stimulated by PKC agonist TPA and inhibited by PKC inhibitor GF-109203X.(ⅱ) The expression of c-myc and c-jun is stimulated by TPA and inhibited by GF-109203X treatment in early G1 phase.(ⅲ) During G1/S progression,the expression of CyclinD1 is stimulated by TPA treatment and inhibited by GF-109203X treatment.There is no effect on the expression of CDK4.It is likely that PKC pathway regulates G1/S progression through regulating the expression of some early response genes and engine molecules in HeLa cells.     

An improved digital watermarking scheme combining with PKC 

Digital watermarking is the enabling technology to prove ownership on such copyrighted product as software, documents, music, and video, monitor the usage of them, and even trace them back to the user with embedding of unique buyer identification(ID) as a part of watermark into them. This thread of detection will deter users from releasing unauthorized copies. A problem arises when the seller is dishonesty, he has a chance to use the digital watermarking with the buyer ID maliciously and make the buyer receive falseaccusation. In this paper, an improved digital watermarking scheme is introduced to prevent falseaccusation to an honest buyer, which is combined with the advantage of PKC(public key certificate) so that it fits the online transaction and helps to realize secure ecommerce. In addition, the extended application of this scheme is discussed.      

Rabin密码系统的分析与实现

对Rabin算法进行了深入分析 ,并结合Miller Rabin测试算法、AdditionChaining算法及作者给出的大数运算算法 ,用C + +语言实现了Rabin密码系统。     

Prokaryotic expression and characterization of a pea actin isoform （PEAcl） fused to GFP

Actins widely exist in eukaryotic cells and play important roles in many living activities. As there are many kinds of actin isoforms in plant cells,it is difficult to purifyeach actin isoform in sufficient quantities for analysing itsphysicochemical properties. In the present study, apea(pisum Sativum L.)actin isoform (PEAc1)fused to His-tag at its amino terminus and GFP(green fluorescent protein)atits Carboxyl terminus were expressed in E. coli in inclusionbodies. The fusion protein (PEAc1-GFP)was highly purifiedwith the yield of above 2 mg/L culture by dissolving inclu-sions in 8 mol/L urea,renaturing by dialysis in a gradient of urea,and affinity binding to Ni-resin. The purified mono-meric PEAc1-GFP could efficiently bind on DNase I andinhibit the latter抯 enzyme activity. PEAc1-GFP could po-lymerise into green fluorescent filamentous structures(F-PEAc1-GFP),which could be labelled byTRITC-phalloidin,a specific agent for observing microfila-ments. The PEAc1-GFP polymerlzation curve was identicalwith that of chicken skeletal muscle actin. The critical con-centration for PEAc1-Gfp to polymerise into filaments is 0.24 μmol/L.The F-PEAc1-GFP could stimulate myosinMg-ATPase activity in a protein concentration dependantmanner (about 4 folds at 1 mg/mL F-PEAc1-GFP). The re-sults above show that the PEAc1 fused to GFP retained theassembly characteristic of actin, indicating that gene fusion,prokaryotic expression, denaturation and renaturation,andaffinity chromatography is a useful strategy for obtainingplant actin isoform proteins in a large amount.     

Effect of PKC pathway on G1/S progression control in HeLa cells

The effect of PKC activity on G₁/S progression in HeLa cells has been studied. The result shows that (ⅰ ) PKC activity alteration in G₁ phase affects G₁/S progression in HeLa cells. It has been observed that G₁/S progression is stimulated by PKC agonist TPA and inhibited by PKC inhibitor GF-109203X. ( ⅱ) The expression of c-myc and c-jun is stimulated by TPA and inhibited by GF-109203X treatment in early G₁ phase. (ⅲ ) During G₁/S progression, the expression of CyclinD₁ is stimulated by TPA treatment and inhibited by GF-109203X treatment. There is no effect on the expression of CDK4. It is likely that PKC pathway regulates G₁/S progression through regulating the expression of some early response genes and engine molecules in HeLa cells.     

拟南芥PP2A B′调节亚基β亚型抗体的制备及鉴定

拟南芥中,蛋白磷酸酶2A(PP2A)B′调节亚基有9个亚型,其中α亚型和β亚型是油菜素内酯(BR)信号通路的正调节子,它们能使转录因子BZR1脱磷酸化.选择β亚型特异的一段多肽P109,利用大肠杆菌表达系统表达并纯化了连有HIS标签和GST标签的融合蛋白HIS-P109和GST-P109.以HIS-P109作为抗原,免疫新西兰兔,获得抗体,然后用GST-P109对抗体进行了亲和纯化.利用此纯化的抗体在不同的拟南芥材料中免疫印迹检测β亚型蛋白的表达,证实制备的抗体能与拟南芥PP2AB′调节亚基β亚型特异性反应,为深入研究PP2A在BR信号转导途径中的功能提供了有力工具.