补光对越冬灰仓鼠体重、主要器官指数及精子数量的影响

目的研究补光对灰仓鼠(Cricetulus migratorus)越冬时脏器器官的影响。方法室温下将其分为自然光照组和补充光照组,分别在第0、30、48和150天时测定动物的体重和脏器器官的重量,应用涂片法检查精子的数量。结果自然光照时,精子数量在冬至时变化不大,但冬至后第18天,灰仓鼠的睾丸系数降到最低值,精子数量仅为422枚,第150天时恢复到正常繁殖状态,精子数量达到7440枚。其他脏器指数在冬至时最高,第150天时最低。补充光照后,雌雄鼠体重高峰值时间均比自然光照组提前100 d,各器官指数变化与体重变化情况相类似,但睾丸和子宫系数维持稳定,精子数量未发现减少。结论在自然光照时越冬灰仓鼠的脏器指数逐渐下降,第150天时脏器指数达至最高值,睾丸指数在冬至后第18天下降到最低值,处于非繁殖状态。补充光照后,越冬灰仓鼠的精子数量和子宫指数变化不大,一直维持繁殖状态。     

小RNA病毒和小DNA病毒的三维结构模型

本文综述了小RNA病毒和小DNA病毒的主要结构特征,绘制出了它们的三维结构模型,从中找出了两者间的共同点和差异,为进一步研究两种病毒提供了依据。     

涡虫在研究药物成瘾机制中的应用

药物成瘾危害人类健康并带来经济和社会问题,而滥用药物所造成的身体损害、身体依赖和戒断综合征的治疗等问题的解决仍存在困难.涡虫具有原始的中枢神经系统,其神经递质系统与哺乳类相似,具有易观察可量化的戒断反应,具有易饲养、低成本、无伦理问题等优于哺乳类实验动物的特点,因而迅速成为新的神经药理学在体动物实验模型.本文对涡虫的优点及其在药物成瘾机制等方面的研究进展进行综述,为药物成瘾机制及其治疗的研究提供新的思路.     

A novel membrane based process to isolate photosystem-I membrane complex from spinach

The isolation of photosystem-I (PS-I) from spinach has been conducted using ultrafiltration with 300 kDa molecular weight cut-off polyethersulfone membranes. The effects of ultrafiltration operating conditions on PS-I activity were optimized using parameter scanning ultrafiltration. These conditions included solution pH, ionic strength, stirring speed, and permeate flux. The effects of detergent (Triton X-100 and n-dodecyl-beta-D-maltoside) concentration on time dependent activity of PS-I were also studied using an O₂ electrode. Under optimized conditions, the PS-I purity obtained in the retentate was about 84% and the activity recovery was greater than 94% after ultrafiltration. To our knowledge, this is the first report of the isolation of a membrane protein using ultrafiltration alone.     

高原世居藏族α、β珠蛋白编码基因的克隆与测序

目的:通过对高原世居藏族α、β珠蛋白编码基因的分析,探讨藏族Hb高氧亲合力的分子机制.方法:高原现场采集健康成年男性藏族人骨髓样品,提取总RNA,通过逆转录聚合酶链反应(RT-PCR)获得人α和β珠蛋白的cDNA,与PGEM-T Easy质粒连接后,将α和β珠蛋白的cDNA转化JM109大肠杆菌中扩增培养,经酶切鉴定后测序,结果与NCBI数据库进行同源性比较.结果:藏族人α珠蛋白的cDNA与NCBI数据库登录的人cDNA序列相同,没有突变位点.一例藏族人β珠蛋白143位密码子发生了氧亲和力增高的碱基突变(CAC-＞CGC),其对应的氨基酸由His变为Arg(即Hb Abruzzo).结论:藏族人高氧亲和力变种的发现,为今后高原低氧适应相关基因的研究提供了线索.     

Enhanced Biological Hydrogen Production from Escherichia coli with Surface Precipitated Cadmium Sulfide Nanoparticles

The precipitation of cadmium sulfide nanoparticles is induced on the surface of Escherichia coli , and the biological hydrogen production efficiency under visible light (VL) irradiation is investigated. When endogenous [Ni–Fe]‐hydrogenase is anaerobically induced, an additional 400 µmol of hydrogen gas is generated within 3 h from the hybrid system suspension (50 mL) under VL irradiation (2000 W m^?2), corresponding to an increase in hydrogen production of ≈30%. The apparent quantum efficiencies of the hybrid system under 470 and 620 nm VL irradiation are 7.93% and 9.59%, respectively, which are higher than those of many photoheterotrophic bacteria. Furthermore, the mechanism of the enhanced hydrogen evolution is investigated. The interaction between photogenerated electrons and cells of E. coli is confirmed by heat‐treatment, electron‐scavenger, and separation studies. The acceleration of pyruvate generation, inhibition of lactate fermentation, increase of formate concentration, stimulation of hydrogenase activity, and elevation of nicotinamide adenine dinucleotide (NAD)H/NAD ratio in the hybrid system are responsible for the enhanced hydrogen production. A feasibility study is also conducted using wastewater and natural sunlight for the hydrogen production by the hybrid system. An additional 120 µmol of hydrogen is generated from the hybrid system within 3 h under these conditions using natural resources.     

基于细胞三维培养的气道平滑肌细胞收缩效应检测方法的建立与应用

气道平滑肌细胞(airway smooth muscle cells,ASMCs)是引起哮喘患者气道收缩狭窄、呼吸阻力增加的主要效应细胞。ASMCs收缩效应检测是研究哮喘病理生理机制、评估或研发新的支气管舒张药物的重要实验依据。而常用的活体组织张力检测以及单层培养ASMCs显微镜形态观察等方法存在样品取材或测量误差等问题。该研究利用胶原蛋白凝胶构建气道平滑肌细胞的三维立体培养模型,将凝胶与培养孔壁分离,在不同的时间点记录细胞收缩力作用下凝胶面积的变化值,以此反映ASMCs的收缩效应。结果显示,0.1,1,10 mmol/L的乙酰胆碱(acetylcholine,Ach)刺激后,凝胶面积均显著缩小,随着剂量增加ASMCs的收缩反应增强。提前加入肌球蛋白ATP酶抑制剂BDM(butanedione monoxime),能明显抑制Ach诱导的ASMCs收缩反应,说明该方法的可重复性和准确性好。     

大鼠初级感觉神经元P2X3受体的表达及其与SP的关系

目的研究在大鼠初级感觉神经元细胞上P2X3受体的表达情况及其与P物质的关系。方法取SD大鼠背根神经节(DRG)和三叉神经节(TG)固定后切片;用抗P2X3受体抗体和抗SP抗体进行免疫组织化学反应,并通过两种不同的显色方法同时进行P2X3受体和SP的双标。结果P2X3免疫反应阳性细胞主要集中在小细胞和中等细胞(其中在TG,P2X3-ir阳性神经元约占整个细胞的24.8%;在DRG约31.7%的神经元是P2X3-ir阳性),并且在DRG和TG细胞上均存在有P2X3受体和SP共存(TG上的双标细胞占P2X3-ir阳性细胞总数的36.26%,DRG上占46.81%)。结论由于ATP门控阳离子通道受体P2X3本身就与伤害性感受的初级传入有关,而它与SP的共存可提示当组织中的ATP释放时可以通过P2X3受体作用于含SP的伤害性感觉神经末梢上,促使SP释放引起痛觉过敏。     

A novel rice C2H2-type zinc finger protein lacking DLN-box/EAR-motif plays a role in salt tolerance

A cDNA for the gene ZFP182, encoding a C2H2-type zinc finger protein, was cloned from rice by RT-PCR. ZFP182 codes an 18.2 kDa protein with two C2H2-type zinc finger motifs, one nuclear localization signal and one Leu-rich domain. The DLN-box/EAR-motif, which exists in most of plant C2H2-type zinc finger proteins, does not exist in ZFP182. The expression analysis showed that ZFP182 gene was constitutively expressed in leaves, culms, roots and spikes at the adult rice plants, and markedly induced in the seedlings by cold (4 degrees C), 150 mM NaCl and 0.1 mM ABA treatments. The approximate 1.4 kb promoter region of ZFP182 gene was fused into GUS reporter gene and transformed into tobacco. The histochemical analysis revealed that GUS expression could not be detected in transformed tobacco seedlings under normal conditions, but strongly observed in tobacco leaf discs and the vascular tissue of roots treated with NaCl or KCl. Expression of ZFP182 in transgenic tobacco and overexpression in rice increased plant tolerance to salt stress. These results demonstrated that ZFP182 might be involved in plant responses to salt stress.     

Activation of the RalGEF/Ral pathway promotes prostate cancer metastasis to bone

A hallmark of metastasis is organ specificity; however, little is known about the underlying signaling pathways responsible for the colonization and growth of tumor cells in target organs. Since tyrosine kinase receptor activation is frequently associated with prostate cancer progression, we have investigated the role of a common signaling intermediary, activated Ras, in prostate cancer metastasis. Three effector pathways downstream of Ras, Raf/extracellular signal-regulated kinase (ERK), phosphatidylinositol 3-kinase, and Ral guanine nucleotide exchange factors (RalGEFs), were assayed for their ability to promote the metastasis of a tumorigenic, nonmetastatic human prostate cancer cell line, DU145. Oncogenic Ras promoted the metastasis of DU145 to multiple organs, including bone and brain. Activation of the Raf/ERK pathway stimulated metastatic colonization of the brain, while activation of the RalGEF pathway led to bone metastases, the most common organ site for prostate cancer metastasis. In addition, loss of RalA in the metastatic PC3 cell line inhibited bone metastasis but did not affect subcutaneous tumor growth. Loss of Ral appeared to suppress expansive growth of prostate cancer cells in bone, whereas homing and initial colonization were less affected. These data extend our understanding of the functional roles of the Ral pathway and begin to identify signaling pathways relevant for organ-specific metastasis.