"非生物因素对生物的影响"探究教学设计

介绍了探究教学模式在初中生物学实验教学中的实践与应用.课堂教学过程分为3个步骤:A.实验前讨论研究的问题并作实验设计;B.实验过程中获取数据;C.实验后学生讨论得出实验结论.整个教学过程中突出了学生的主动性和创造性,突出了如何将探究实验与学生获得的概念联系起来.突出了培养学生的逻辑型思维能力.     

“探究模拟酸雨对丰年虾孵化率的影响”一节实验教学设计

在“探究酸雨对生物的影响”的实验中,将实验对象由植物调整为丰年虾（Artemia salina）,使学生认识到酸雨除了对植物有害,还对其他生物有危害。本实验设定了4个pH梯度来探究酸雨对丰年虾孵化的影响,实验结果采用笔式数码显微镜观察计数,启发学生用棉花纤维或碘液来限制丰年虾的运动以便于计数。本实验从实验对象、用具和方法 3个方面进行了创新。在课堂教学中,从了解实验背景、选取实验对象,到设计实验步骤及操作实验,都以问题导向为原则,凸显学生的主体地位,培养学生的生物学学科核心素养。     

口腔微生物学实验课程三年教学总评分析

增设口腔微生物学实验课,根据口腔医学特色设计系列实验,培养学生的基础、专业、综合、创新能力,经过3年的教学结果,对实验课程的建设进行总体评估.教学方式采用学生两两配对模式,采集口腔牙菌斑,选择性MS培养基分离致龋菌,BHI液体培养基纯化培养,革兰染色和生化糖管鉴定致龋菌.对2009～2011年3年度的实验教学结果进行总体分析.经过实验课的系统教学,学生的口腔微生物学科研能力都有所提高,评分“A”的比例从实验一的56.3％提高到实验四的78.2％,评分“C”的比例从实验一的31.1％下降为实验四的4.6％.口腔微生物学实验教学能够加深学生对理论知识的理解,有助于培养学生的专业技能和科研能力,提高口腔医学教育质量.     

一种源自人α-2-巨球蛋白的抗菌肽A2M3及其对金黄色葡萄球菌的抑菌机制

【目的】在人的鼻腔中鉴定出一种源自α-2-巨球蛋白的抗菌肽(命名为A2M3),并探究其对金黄色葡萄球菌(Staphylococcus aureus)的抑菌作用和机制。【方法】结合生物信息学技术对人类鼻液的质谱结果进行分析,并筛选潜在抗菌肽;通过微量稀释法和平板涂布法分别分析A2M3对金黄色葡萄球菌最低抑菌浓度(minimum inhibitory concentration, MIC)和时间杀伤曲线(time-kill curve);采用透射电镜、碘化丙锭(propidium iodide, PI)摄取实验、流式细胞术和核酸蛋白质泄露实验分析A2M3对金黄色葡萄球菌膜完整性、膜通透性的影响;通过凝胶阻滞实验和荧光光谱实验探究A2M3对金黄色葡萄球菌基因组DNA的影响。【结果】利用生物信息学技术筛选出源自α-2-巨球蛋白的潜在抗菌肽A2M3,其对金黄色葡萄球菌的MIC为125.0 μg/mL,且能在3 h内完全杀灭细菌。A2M3通过增加细胞膜的通透性,促使核酸和蛋白质泄漏,继而穿过细胞膜嵌入DNA的碱基对,影响细菌的基因功能,从而导致菌体死亡。【结论】A2M3对金黄色葡萄球菌的抑菌机制涉及多靶点协同作用,能够改变细菌细胞膜的通透性,影响细菌的基因功能。这一发现揭示了从人体体液中筛选和分离抗菌功能肽的潜在应用价值。     

细胞大小测定及细胞计数实验的教法改进及注意事项

细胞大小测定及细胞计数实验是细胞生物学的基础实验,在实验过程中经常出现仪器损耗、学生对血球计数板了解不深入的问题。为了解决这些问题,通过长期的实验教学,从实验前、中、后3个阶段提出改进方法,并对实验过程中的注意事项进行了阐述,达到充分利用实验仪器资源,提高学生学习主动性的目的。     

KDM3A全长及截短质粒构建及其在细胞中的定位探究

赖氨酸去甲基化酶3A(lysine demethylase 3A,KDM3A)是组蛋白去甲基化酶家族成员之一,通过特异性对组蛋白H3K9甲基化进行去甲基化的作用调控基因转录。目前研究证实KDM3A在肝癌、雌激素受体(estrogen receptorα,ERα)阳性乳腺癌及前列腺癌等肿瘤中发挥促癌作用,但其具体作用机制仍有待更深层次的研究。为深入解析KDM3A在各种肿瘤中的作用及其分子机制,本研究利用分子生物学方法构建了KDM3A基因的全长和截短基因表达质粒,酶切鉴定及测序证实KDM3A全长及截短基因的表达质粒构建成功。在此基础上,再将构建成功的上述多种表达质粒分别转染到HEK293细胞和MCF7细胞中,进行Western blotting和免疫荧光共聚焦实验,进一步对各重组表达质粒在培养的哺乳动物细胞中的蛋白表达及蛋白细胞定位进行初步探究。Western blotting结果显示KDM3A全长基因表达的蛋白约147 kD,其他KDM3A截短基因表达的蛋白均对应其特异性的蛋白条带;免疫荧光共聚焦实验结果显示KDM3A全长质粒以及pN1、pN2、p N3、pΔ截短质粒表达的蛋白分布在细胞核,pC1、pC2截短质粒表达的蛋白分布在细胞质,pC3截短质粒表达的蛋白分别分布于细胞核与细胞质。本实验为后续深入研究KDM3A在肿瘤中的作用及分子机制提供了实验基础。     

固定化酵母细胞实验的再探究

高中生物学选修1课题3中"酵母细胞的固定化"实验在2019年新增为高考内容,对学生和教师是一个新挑战。该实验操作难度大,成功率低,明显影响学生的实验热情。从酵母细胞的活化条件、海藻酸钠的溶化条件和海藻酸钠的配制等实验疑难点入手,对该实验进行再探究,建立多组对照实验,逐步优化,提高了实验成功率,为学生实验或演示实验提供参考。     

植物细胞吸水和失水演示实验的改进

在初中生物第一册“根对水分的吸收”一节内容中 ,为了帮助学生理解根毛细胞吸水和失水的原理 ,安排了萝卜吸水和失水的演示实验。但是在此演示实验中 ,只是根据萝卜块变硬变软而推断植物细胞可以吸水也可以失水 ,似乎不够严谨。为了使该实验更加严谨、科学 ,我们对其做了些改进。1　准备在上课前一天 ,组织兴趣小组的同学做准备工作 ,把 1个约 2 50 g重的萝卜去掉皮后分成 3份 ,用刀仔细、耐心地削 ,直到在天秤上称出等重的 3块萝卜块。再取3只烧杯 ,A烧杯注入盐水 ,放入 A萝卜块 ,烧杯内液面控制在 2 0 0 ml刻度上 ;B烧杯注入清水 ,放入…     

人von Willebrand因子A1和A3功能结构域嵌合体的表达及生物学功能

vWF介导血小板粘附到细胞外基质 ,在血栓形成过程中发挥重要作用 ,可通过阻断vWF与细胞外基质的结合阻止血小板的粘附 .应用RT PCR方法从人脐静脉内皮细胞中克隆vWF分子A1、A3区基因并在大肠杆菌中表达 ,表达的重组蛋白量占菌体总蛋白 12 6 % ,包涵体经过变性剂溶解、纯化和复性 ,获得重组蛋白 (rvWF A1 A3) .应用流式细胞术检测rvWF A1 A3与血小板膜糖蛋白 (GPⅠb)的结合功能 ;血小板聚集实验观察rvWF A1 A3对瑞斯托霉素 (ristocetin)诱导的血小板聚集 (RIPA)的影响 ;ELISA胶原结合实验及竞争抑制实验分析rvWF A1 A3与胶原的结合活性 .结果显示 :rvWF A1 A3嵌合体与血小板的结合阳性率为 70 4 % .rvWF A1 A3嵌合体不能引起血小板的聚集 ,但rvWF A1 A3嵌合体与血小板温育后可以阻断ristocetin诱导人血浆vWF对血小板的聚集作用 ,而且呈剂量依赖性 ,IC50 的rvWF A1 A3浓度为 0 76 μmol L ,当浓度为 1 17μmol L时抑制率最高达 76 8% .rvWF A1 A3具有良好的胶原结合活性 ,同时它可以竞争性抑制vWF与Ⅲ型胶原的结合 ,抑制率为 76 % .表明rvWF A1 A3可作为阻断剂用于干预vWF介导的血小板粘附过程 ,同时又可以阻断血浆vWF与血小板GPIb结合抑制血小板聚集 ,具有良好的抗栓应用前景 .     

九蒸九晒熟地黄中的紫罗兰酮类化合物

本实验对九蒸九晒熟地黄进行进一步的化学成分研究,采用多种柱色谱技术从"九蒸九晒"熟地黄70%丙酮提取物中分离得到3个紫罗兰酮类化合物,运用现代波谱技术并结合参考文献对其结构进行鉴定,分别为sec-hydroxyaeginetic acid-2-O-β-D-glucopyranoside(1)、frehmaglutin A(2)和dihydroxy-β-ionone(3)。其中化合物1为新化合物,化合物2和3为首次从熟地黄中分离得到。采用MTT法研究化合物1～3对人恶性黑色素瘤A375细胞的细胞毒作用。结果表明,化合物1～3在25μM浓度下均能显著的降低A375的细胞活力,提示其可能具有A375细胞毒活性。     

Using the two-hybrid screen in the classroom laboratory

The National Science Foundation and others have made compelling arguments that research be incorporated into the learning of undergraduates. In response to these arguments, a two-hybrid research project was incorporated into a molecular biology course that contained both a lecture section and a laboratory section. The course was designed around specific goals for educational outcomes, including introducing research to a wide range of students, teaching students experimental design and data analysis, and enhancing understanding of course material. Additional goals included teaching students to search genomic databases, to access scientific articles, and to write a paper in scientific format. Graded events tested these goals, and a student evaluation indicated student perception of the project. According to our analysis of the data, the yeast two-hybrid screen was a success: several novel clones were identified; students met expectations on graded lab reports, the poster session, and the final paper; and evaluations indicated that students had achieved the outlined goals. Students indicated on the evaluations that the research project increased their interest in research and greatly improved understanding of the course material. Finally, several students in the course intend to submit the findings of the research project to an undergraduate research journal.     

Designing and implementing a new advanced level biology course

Salters-Nuffield Advanced Biology is a new advanced level biology course, piloted from September 2002 in England with around 1200 students. This paper discusses the reasons for developing a new advanced biology course at this time, the philosophy of the project and how the materials are being written and the specification devised. The aim of the project is to provide an up-to-date course that interests students, is considered appropriate by teachers and other professionals in biology, and takes full advantage of modern developments in biology and in teaching.     

微生物学检验实验教学的改革与实践

改革传统的微生物学检验实验教学,组织学生到大型医院和医学检验类企业开展实验。按照微生物检验室工作流程,分接种、培养、鉴定3大项目进行实验教学。同时,让学生与企业员工进行深入交流,体验企业文化氛围,感受人文关怀,提高了实验教学质量,让学生树立更科学合理的就业观和择业观。     

Laboratory practical work as a technological process

Laboratory practical work is commonly intercalated with theoretical and seminar classes in packages that cover single units of a given course program. Emphasis is put in to illustrate important theoretical concepts and in to improve students' laboratory handling skills. We observed that this involves serious disadvantages, namely (i) students lack an integrated view of the subjects, (ii) time constraints for each experimental session preclude students to become familiar with most of the techniques and approaches, (iii) how to manipulate laboratory equipment become more important than the objectives and rational explanation of results, (iv) work planning and evaluation of reproducibility of methods are not considered, (v) elaboration and communication of results are not encouraged. To overcome these limitations we developed a new schedule were students get problem-based learning of theoretical concepts during the first half of the course and plan and execute a laboratory project during the second half. The project is performed within one of three main areas: purification, enzyme kinetics or metabolism/molecular genetics, with β-galactosidase as model system. By inducing a more positive attitude in the students towards the practical laboratory work, this schedule allowed us to avoid the mentioned disadvantages while keeping the traditional practical laboratory work objectives met.     

Multiweek cell culture project for use in upper-level biology laboratories

This article describes a laboratory protocol for a multiweek project piloted in a new upper-level biology laboratory (BIO 426) using cell culture techniques. Human embryonic kidney-293 cells were used, and several culture media and supplements were identified for students to design their own experiments. Treatments included amino acids, EGF, caffeine, epinephrine, heavy metals, and FBS. Students researched primary literature to determine their experimental variables, made their own solutions, and treated their cells over a period of 2 wk. Before this, a sterile technique laboratory was developed to teach students how to work with the cells and minimize contamination. Students designed their experiments, mixed their solutions, seeded their cells, and treated them with their control and experimental media. Students had the choice of manipulating a number of variables, including incubation times, exposure to treatment media, and temperature. At the end of the experiment, students observed the effects of their treatment, harvested and dyed their cells, counted relative cell numbers in control and treatment flasks, and determined the ratio of living to dead cells using a hemocytometer. At the conclusion of the experiment, students presented their findings in a poster presentation. This laboratory can be expanded or adapted to include additional cell lines and treatments. The ability to design and implement their own experiments has been shown to increase student engagement in the biology-related laboratory activities as well as develop the critical thinking skills needed for independent research.     

生物化学实验课程化的改革与实践

现行的生物化学实验教学存在着目标定位过时、教学内容与方法滞后等诸多问题,难以满足现代教育的需要。为适应社会发展,培养具有实践能力和创新能力的人才,必须对传统的生物化学实验教学进行改革和优化。通过实验教学课程化等一系列改革,探索构建现代生物化学实验教学新模式和课程新体系,着力培养学生的综合能力。     

医学微生物学实验教学改革的探索与实践

以麻醉学专业学生为研究对象,进行了传统实验教学与新实验教学模式的对比研究。新实验教学模式围绕如何在实验教学中培养学生的创新能力,从实验教学计划、教学内容、教学方法和手段、实验考核方法进行了改革和探索,增设了综合性与探索设计性实验,研制了实验多媒体课件。结果显示新实验教学模式有利于培养学生的动手能力、科研思维、创新能力以及综合分析能力,教学效果优于传统实验教学。创建了适合于培养麻醉学专业的医学微生物学实验教学体系。     

开放实验室条件下的动物学实验教学改革新探

探讨了充分利用开放实验室进一步改革动物学实验教学的新方法：把开展大学生课题研究融入动物学实验教学、充分利用动物标本室加强动物学实验教学、以学生为主体调整动物学实验的教学内容以及结合相关产学研课题提高动物学实验教学的效率。结合实际条件激发学生学习的兴趣和参加实验的积极性,提高了实验效果,培养了学生的创新精神和实践能力。     

基础生物化学实验教学对学生技能的培养

面对国内实验教学的新形势和新要求,改进和完善本科实验教学日益紧迫。介绍了本科基础生物化学实验教学的内容与实践,根据生化实验课的特点,对实验教学内容、方式等进行改进,强调了以基本技术围绕基本实验与综合性实验为中心,培养学生的实践能力、创新能力与科学思维,重点强化了实验技能与素质的训练,探索了生化实验教学中培养高素质、综合型创新人才之路。