Effects of ozone on the photosynthetic apparatus and leaf proteins during leaf development in wheat

Leaves of Triticum aestivum cv. Avalon were grown in an atmosphere that contained 150 nmole mol^-1 ozone for 7h each day. After leaves had reached maximum size, the leaf blade was divided into three sections to provide tissue of different age, the youngest at the base of the blade and the oldest at the leaf tip. The ozone treatment was found to decrease significantly the light-saturated rate and quantum yield of CO₂ assimilation and the maximum quantum yield of photosystem II photochemistry in the oldest leaf section. No effects were found on the basal and middle sections of the leaf. These ozone-induced decreases in the photosynthetic parameters were associated with decreases in the efficiency of utilization of light for CO₂ assimilation at the photon flux density under which the leaves were grown. The depression in photosynthetic performance of tissue near the leaf tip was accompanied by large decreases in the contents of total, soluble and thylakoid proteins and chlorophyll. There was also found to be a preferential loss of ribulose-1,5-carboxylase-oxygenase. These ozone-induced changes in chlorophyll and protein contents and the photosynthetic activities of the leaf tissue were similar to changes normally associated with leaf senescence. Two-dimensional polyacrylamide gel analyses of leaf proteins demonstrated the loss of some minor, and unidentified, proteins, whilst another group of minor proteins appeared. It is concluded that daily exposure of the leaf to 150 nmol mol^-1 ozone for 7h had no effect on the development of the photosynthetic apparatus and its activities during leaf expansion, but it did promote the onset of premature senescence in fully expanded tissue that resulted in a loss of pigments, proteins and photosynthetic capacity and efficiency.     

微生物-矿物相互作用及界面显微分析研究进展

微生物-矿物界面的相互作用贯穿着整个生物浸矿过程,在矿物生物浸出中至关重要,受到微生物的代谢特征、矿物表面结构和物质形态及环境条件的多重交叉影响。研究微生物-矿物界面的相互作用相关的微生物选择性吸附、矿物表面元素形态转化和钝化层、微生物铁硫氧化活性和微生物群落以及胞外物质的组成和性质等的演化,有利于了解微生物-矿物界面作用机制及其关键影响因素和影响机制,从而为优化浸出工艺提供科学的理论依据。达到这些目的,界面的(原位)显微分析手段和技术的进步也至关重要。本文对近些年来上述两方面的研究进行了综述。     

外科治疗囊性听神经瘤14例临床观察

目的：探讨囊性听神经瘤的临床特点及手术经验。方法：回顾分析2006年1月-2010年12月我院收治的14例囊性听经瘤的临床资料。结果：肿瘤全切除12例,不全切除2例,无死亡病例,术后4例病人面瘫加重,1例病人听力丧失。结论：与实质性听神经瘤相比,囊性听神经瘤体积较大,病程短,始发症状不典型,颅神经常被累及,可不发生内听道扩大,脑积水发生率低,手术效果差。     

噬菌体呈现技术制备结肠癌抗独特型抗体

 以纯化的鼠抗人结肠癌细胞单克隆抗体 (简称单抗 )MC5与钥孔血蓝素 (KLH)的交联物经腹腔免疫Balb c小鼠 ,取脾分离mRNA .RT PCR分别扩增抗体重、轻链可变区基因片段 (VH 和VLcD NA ,大小分别约为 340bp和 32 0bp) ,二者经linkerDNA连接形成ScFv(singlechainvariablefragment)DNA(约 75 0bp) .将ScFvDNA与噬菌粒载体pCANTAB5E的连接产物转化于大肠杆菌TG1,经辅助噬菌体M13KO7感染后 ,获得重组噬菌体抗体ScFv文库 .以单抗MC5对ScFv文库进行 4轮亲和筛选后 ,随机挑取 80个克隆经酶联免疫吸附实验 (ELISA)筛选出 2 2个呈现ScFv形式抗独特型抗体(抗 IdScFv)的噬菌体单克隆 .竞争抑制实验表明 ,在 2 2个阳性克隆中有 4个克隆所呈现的抗 IdScFv属β或γ型 .针对单抗MC5的噬菌体呈现型抗 IdScFv的制备 ,为筛选新的结肠癌重组抗 Id瘤苗候选分子奠定了基础     

基于PBL 构建的儿科学实习教学

PBL教学以问题为核心,以启发的方式和讨论的方式进行教学,该教学方法可以充分调动学生学习的主动性,比传统的教学方法更能有效完成儿科学实习教学,且有利于早期培养医学生良好的临床问题处理能力。本文论述如何将PBL教学模式引入儿科学实习教学,以及PBL教学法在儿科学实习教学中需注意的问题:问题设计合理、根据病人的不同调整教学方法、根据实习同学的不同调整教学内容和带教老师正确掌握角色任务。     

Functional characterization of the genes tauO, tauK, and tauI in the biosynthesis of tautomycetin

Tautomycetin is a specific protein phosphatase I inhibitor. In an effort to elucidate the biosynthetic mechanism of tautomycetin, we inactivated genes of the tautomycetin biosynthetic gene cluster, tauI, tauO, and tauK, which encode for putative P450 oxidase, citryl-CoA lyase, and esterase enzymes, respectively. The mutant STQ0606 (??tauO) did not produce any detectable amount of tautomycetin intermediates but could convert dialkylmaleic anhydride to tautomycetin, strongly indicating that TauO was involved in dialkylmaleic anhydride biosynthesis. STQ1211 (??tauK) accumulated dialkylmaleic anhydride, whereas the cofermentation of STQ1211 (??tauK) and STQ0606 (??tauO) restored the production of tautomycetin. Together, these results suggest that TauK was responsible for the conjugation of dialkylmaleic anhydride and the polyketide moiety in tautomycetin biosynthesis. The disruption of tauI resulted in the accumulation of 5-des-keto-tautomycetin, revealing that TauI was responsible for the oxidation at C5 as the last step. Although the shunt pathways were involved in the biosynthesis of tautomycetin, the main post-polyketide synthase tailoring steps were dehydration, decarboxylation and oxidation, taking place consecutively. This study allowed us to predict the biosynthesis of tautomycetin more accurately and provided novel insights into the mechanism of the biosynthesis of tautomycetin.     

金银忍冬叶的解剖学初步研究

应用徒手切片法对金银忍冬叶进行了解剖学的初步研究,旨在为其解剖学、分类学及生药学的研究提供相应基础。结果表明:金银忍冬叶为异面叶,上下表皮细胞各一列,上表皮没有气孔,下表皮气孔分布的气孔指数为14.3%～25%,多为不定式气孔,栅栏组织为1层,含叶绿体较多,海绵组织内含草酸钙簇晶,表皮细胞外壁加厚形成角质层,皮层有厚角组织,主脉为外韧维管束等。上述特征说明金银忍冬叶的解剖结构与其生理功能及生态环境是相适应的。     

库克Noni果汁多糖含量及分子量测定

建立测定库克Noni果汁中多糖含量及分子量的方法。通过醇沉法分离Noni果汁多糖,进一步分离纯化得到均一多糖组分;用精制Noni果汁多糖测得该多糖对葡萄糖的换算因子,对多糖含量进行定量测定;并通过SE-HPLC(Size Exclusion-High Performance Liquid Chromatography)法测定了该多糖的相对分子量。结果表明,多糖含量测定方法简便可行,供试液在4 h内显色稳定,重现性较好,平均回收率为99.3%,RSD为1.93%(n=3);测得该多糖的相对分子量为1140 KDa。     

内皮素1的克隆表达及其诱发抗体的初步研究

目的：克隆内皮素1（endothelin 1,ET1）基因、表达ET1融合蛋白,以期诱导机体产生ET1抗体,中和患者体内过量的ET1。方法：根据人ET1的多肽序列合成ET1基因,将其插入到pThioHisA的EcoRI和 SalI位点,重组质粒pThioHisA-ET1进行酶切鉴定及序列测定验证后转化TOP10,IPTG诱导的重组菌经SDS-PAGE检测融合蛋白Thioredoxin-ET1的表达量;表达的融合蛋白用ProBond亲合层析纯化并经HPLC鉴测其纯度;每只小鼠按25、50、100ug/次剂量的Thioredoxin-ET1每两周免疫一次,共4次,最后一次免疫10d后制备抗血清,经Western blot和ELISA检测证明Thioredoxin-ET1融合蛋白具有ET1免疫反应原性。结果：经过质粒酶切鉴定及序列分析表明,构建了正确的融合表达载体pThioHisA-ET1,用1mmol IPTG诱导工程菌,融合蛋白Thioredoxin-ET1的表达量占菌体总蛋白的50%,多以包涵体的形式存在,包涵体经洗涤,变性和复性后,用ProBond亲合层析纯化得到了Thioredoxin-ET1融合蛋白,经HPLC鉴测其纯度为90%。制备的抗血清中ET1抗体的效价可达104。结论：应用Thioredoxin-ET1融合蛋白可以诱发机体产生ET1抗体,为研究ET1在患者体内的过量表达及对患者的免疫治疗开辟了新的途径。     

中国简栉叶蜂属(膜翅目,叶蜂科)二新种

记述采自河南和湖南省的叶蜂科突瓣叶蜂亚科2新种:烟翅简栉叶蜂Trichiocampus infumatunus sp.nov.和淡足简栉叶蜂 Trichiocampus femoratinus sp.nov,.编制了简栉叶蜂属中国已知种的分种检索表.新种模式标本保存于中南林业科技大学昆虫模式标本室.