创设教学情境,优化学习环境——汉语拼音教学体会点滴

汉语拼音是一种抽象的表音符号,它难读、难记、易混、易忘。按大纲和教学进度安排,要一年级新生在入学后六周内既要读准声母、韵母、声调和整体认读音节,又要学会拼音方法,能直呼或拼读音节,这对初入学的儿童来说是比较困难的。怎样才能如期完成教学任务?我们要根据儿童年龄和心理特点,优化教法、学法,组织、活动”,激励参与,创设学习拼音的良好氛围,使儿童变“苦学”为乐学,打好拼音基础,迈好汉语学习的第一步。 一、创设教学情境,优化学习方法 1、自编儿歌、顺口溜、小谜语,激发兴趣,巩固记忆。如“半圆一个小尾巴,张大嘴巴aaa”;“花衣裳,真美丽,花边加点就是i”;“t和f是姐妹俩,分清钩上和钩下,姐姐钩下读成t,妹妹钩上读成f”;单门n,双门m,小棍赶猪lll等等。这些根据拼音字母音和形编成的儿歌,形象直观,朗朗上口,富有童趣,学生乐学易记。 2、增加拼读机会,调动学习兴趣。如把学生的名字用拼音写在黑板上,让学生“对号入座”,学生兴致很高,就连学习较差的同学也紧盯着黑板读来读去。

THE CONSTRUCTION AND EXPRESSION OF RECOMBINANT SHUTTLE PLASMID WITH OMPL1 GENE FROM LEPTOSPIRA INTERROGANS SEROVAR LAI STRAIN 017 IN BACILLE CALMETTE-GUERIN

Objective.To construct recombinant BCG again st leptospirosis.Methods.We amplified the entire open readin g frame of the OmpL1gene from the genome of the leptospire serovar Lai strain 017.Two recombin ant plasmids pBQ1and pBQ2were constructed by oriented ligation based on the E.coli-BCG shuttle plasmids pMV261and pMV361respectively.The recombinant plasmids were transformed into BCG by electroporation.The rBCGs bearing pBQ1and pBQ2were induced by high temperature of 45℃.Results.The expressed product,a 35kD prote in was detected by SDS-PAGE.The resu lt indicates that pBQ1and pBQ2can express OmpL1in rBCG.Conclusion.The technical methods in this study may help detect the immunogenicity a nd immunoprotection of OmpL1and develop more safe,highl y effective rBCG bearing leptospira l antigen with long-lasting protection.

Genotypic Analysis, Construction of the Expression System and Immunological Identification of the Recombinant Proteins of the LipL32 Gene in the Dominant Serogroups of Leptospira interrogans in China

To investigate the existence of the major outer membrane protein (MOMP) gene LipL32 in 15 dominant Chinese strains of 15 serogroups of Leptospira interrogans and 2 international strains of 2 serogroups of Leptospira biflexa, and to clone and construct the expression system as well as to identify the recombinant proteins, genomic DNAs from strains of leptospira were prepared by routine phenol-chloroform method, and the fragments of the LipL32 gene with the whole length from the strains were amplified with high fidelity PCR. The target amplification products were sequenced after T-A cloning, and the expression system for the genes were thereby constructed. Expression of the recombinant proteins was identified by using SDS-PAGE after induction with IPTG at different dosages. Western blot assays with rabbit antiserum against the whole cell of TR/PatocⅠ of Leptospira and immunized serum with rMOMPs were used to determine the immunoreactivity and immunogenicity of the recombinant proteins. Microscopic agglutination test was used to determine the cross- agglutination titres in rabbit sera immunized with rMOMPs, and the cell adherence model of Leptospira was used to examine the blocking effects of rabbit antisera against these rMOMPs. It was found that the LipL32 gene could be found in all the 17 strains of Leptospira mentioned above with two different genotypes, i.e. LipL32/1 and LipL32/2. Amounts of expressions of rMOMP1 and rMOMP2 after IPTG accounted for 40% and 10% of the total bacterial proteins respectively. Both rMOMP1 and rMOMP2 could combine with the rabbit antiserum against leptospiral TR/PatocⅠ, and could induce the production of agglutination antibodies to these 17 strains of Leptospira with 1∶2 to 1∶64 MAT titres. The rabbit anti-rMOMP1 and anti-MOMP2 antibodies at 1∶2 to 1∶16 dilutions could efficiently block adherence of Leptospira. It concludes that all the Leptospira tested in the present study possess LipL32/1 or LipL32/2 genes, and the constructed expression system can express the rMOMP1 and rMOMP2. These recombinant proteins are showed to have good immunogenicity and satisfactory immunoreactivity.

天麻钩藤饮含药血清对MPP^+诱导PC12细胞损伤保护作用的研究

目的:观察天麻钩藤饮含药血清对1-甲基-4-苯基-吡啶离子(1-methyl-4-phenyl pyridinium,MPP+)诱导的PC12细胞凋亡的影响,并且探讨其作用机制。方法:将48只大鼠随机分为空白组、美多巴组、天麻钩藤饮2.85、5.7、11.4、22.8g/kg剂量组,天麻钩藤饮按照相应剂量灌胃,空白组灌胃等体积生理盐水,美多巴片(0.05g/kg)溶于生理盐水灌胃。采血制备含药和空白血清,常规培养PC12细胞,空白组和模型组给予空白血清,其他5组给予10%含药血清,孵育30min后,再加500μmol/L MPP+共孵育48h后收集细胞,采用MTT法检测细胞存活率,LDH释放检测细胞毒性,Annexin V/PI染色流式细胞术检测PC12细胞凋亡,Western blot检测Bax、Bcl-2、Cleaved-caspase-3蛋白表达水平,分光光度法检测Caspase-3及Caspase-9活性。结果:模型组较空白组细胞活力明显降低,LDH释放率增加,诱导细胞发生凋亡,同时Bax、Cleaved-caspase-3蛋白表达水平增加,而Bcl-2蛋白表达降低,Caspase-3及Caspase-9活性明显增加。与模型组比较,10%的天麻钩藤饮5.7、11.4、22.8g/kg含药血清组细胞活力显著增加,LDH释放率减少,凋亡细胞量减少,Bax、Cleaved-caspase-3蛋白表达水平降低,而Bcl-2蛋白表达升高,Caspase-3及Caspase-9活性降低;而10%的天麻钩藤饮2.85g/kg含药血清组无明显变化。结论:天麻钩藤饮含药血清对MPP+诱导的PC12细胞的凋亡具有保护作用,其机制可能与调节线粒体功能密切相关。