教学课程资源库 更多>>

关键词： TGFbeta family   SMAD   Cell fate   Pluripotency   Stem cell  

摘要： Background: Members of the Transforming Growth Factor-beta (TGF beta) superfamily of cytokines are essential for early embryonic development and play crucial roles in pluripotency and differentiation of embryonic stem cells in vitro. Scope of review: In this review, we discuss how TGF beta. family signals are read by cells and how they are modulated by the cellular context Furthermore, we review recent advances in our understanding of TGF beta function in embryonic stem cells and point out hot topics at the intersection of TGF beta signaling and stem cell biology fields. Major conclusion: TGF beta family signals are essential for early mammalian development and the importance of this pathway is reflected in pluripotent stem cells derived from the mammalian embryo. General significance: Understanding signaling pathways underlying pluripotency and cell fate specification holds promises for the advent of personalized regenerative medicine. This article is part of a Special Issue entitled Biochemistry of Stem Cells. (C) 2012 Elsevier B.V. All rights reserved.

关键词： Biological control   Hydrocharitaceae   Ephydridae   Aquatic weeds  

摘要： Egeria densa (Hydrocharitaceae) is a submerged macrophyte from South America that is a weed in several countries. It crowds out native plants and hinders water use, causing economic and environmental damage. The leafminer fly Hydrellia sp. 1 (Diptera: Ephydridae), was found feeding in E. densa throughout its Argentine distribution, and is currently the only known specialist herbivore of E. densa. It was reared in the laboratory and tested on 25 plant species. This herbivore can cause heavy defoliation in the laboratory and in the field. Hydrellia sp. 1 was found only on E. densa, but in the laboratory it also developed on two other Hydrocharitaceae species in the same family;Egeria naias, and Elodea callitrichoides. Significant oviposition and feeding were only observed on its primary natural host, and to a lesser degree on E. naias. Field studies indicate Hydrellia sp. 1 is present in the field year round, unless the host plant is prostrate for long periods, or covered by floating macrophytes. These results indicate Hydrellia sp. 1 may be a suitable biocontrol candidate for E. densa.

关键词： Conferences   Breeding of animals   Genetics   Genotype & phenotype   Zoology  

摘要： Cole et al highlight the Breeding and Genetics Symposium titled "Systems Biology in Animal Breeding: Identifying relationships among markers, genes, and phenotypes" which was held at the Joint Annual Meeting of the American Society of Animal Science and the American Dairy Science Association in Phoenix, AZ on Jul 15-19, 2012. The primary goal of the symposium was to demonstrate the use of high-density SNP genotypes to determine the complex regulatory relationships among genotypes and phenotypes but also to present methods for studying complex relationships among phenotypes. Case studies from mammalian and avian species were included to emphasize the broad applicability of these methods.

关键词： epigenetics   genetics   development  

摘要： An introduction to this issue of 'Philosophical Transactions of the Royal Society B: Biological Sciences,' in which the authors discuss the role of epigenetics in cell development and differentiation, is presented.

关键词： db   db小鼠   2型糖尿病   基因缺陷   生物学特性  

摘要： 目的研究基因缺陷型2型糖尿病模型动物db/db小鼠的早期生物学特性,为db/db小鼠应用于降糖药物的研究奠定基础。方法采用db/db小鼠为模型组动物,db/m小鼠为对照组动物,测定两组小鼠的体质量、食量、饮水量、空腹血糖、正常饮食血糖、糖耐量、胰岛素耐量;于第14周眼底静脉丛取血,分离血清,测定糖化血清蛋白(GSP)、三酰甘油(TG)、总胆固醇(TC);取肝、胰腺、腹部脂肪等主要脏器组织进行组织病理学检查。结果与对照组比较,db/db小鼠体质量、食量、饮水量显著增加;空腹血糖及正常饮食血糖显著升高,整个实验期血糖水平稳定;糖耐量异常、胰岛素耐量异常,对外源胰岛素敏感性显著降低;血清GSP、TG、TC含量显著升高,腹部脂肪质量显著增加,肝组织不同程度的空泡变性,脂肪组织中脂肪细胞体积增大,胰腺中胰岛细胞胞浆减少、血管扩张。结论 db/db小鼠早期脂质代谢紊乱,血糖、血脂显著升高,糖耐量及胰岛素耐量异常,血糖水平稳定,是研究2型糖尿病较为理想的模型。

关键词： 动物生物学   课程教学   科研素质  

摘要： 根据教学实践,阐述了在动物生物学课程教学中,如何从课堂教学、实验教学、野外综合实习3个环节入手,注重培养学生的科研素质。

关键词： Biohybrid material   Drug depot   Hydrogel   Stimulus-responsive   Synthetic gene network  

摘要： The synthetic synthetic reconstruction of natural gene networks and the de novo design of artificial genetic circuits provide new insights into the cell's regulatory mechanisms and will open new opportunities for drug discovery and intelligent therapeutic schemes. We will present how modular synthetic biology tools like repressors, promoters and enzymes can be assembled into complex systems in order to discover small molecules to shut off antibiotic resistance in tubercle bacteria and to design self-sufficient therapeutic networks. The transfer of these synthetic biological modules to the materials science field enables the construction of novel drug-inducible biohybrid materials for biomedical applications. (c) 2012 Elsevier Inc. All rights reserved.

关键词： 益生菌   生物学特性   比较研究   鉴定  

摘要： 本研究从猪肠道中分离出50株潜在益生菌，与实验室保存的8株鸡源益生菌、7株狐貉源益生菌根据不同来源设置分组。对不同动物来源益生菌在抑致病原菌、抗病毒、降胆固醇和抗氧化方面的生物学特性进行比较分析，并对筛选出的具有综合优势的菌株进行种属鉴定，为深入研究益生菌生物学特性作用机制和应用奠定基础。 采用碳酸钙平板透明圈法，挑取溶钙环明显且革兰氏染色阳性的菌株，从猪粪便中所分离的50株潜在益生菌，依次命名为P1P50，作为实验菌株开展研究工作。同时选取本实验室保存的其他动物来源的益生菌株做比较试验，分别为8株鸡源益生菌，依次命名为C1-C8；7株狐貉源益生菌，依次命名为H1-H7。 检测这些益生菌菌株对致病菌大肠杆菌O78和金黄色葡萄球菌的抑制实验，采用牛津杯法，结果表明所有菌株对两种致病菌均表现出不同程度的抑制作用，并且抑制作用呈现出益生菌菌株的来源差异性、种属差异性和菌株差异性。对大肠杆菌的抑制作用：鸡源＞猪源＞狐貉源，且鸡源的抑制效果显著高于猪源和狐貉源（p＜0.05）；对金黄色葡萄球菌的抑制作用则表现为鸡源＞猪源＞狐貉源，鸡源抑制效果同猪源抑制效果差异不显著（p＞0.05），但同狐貉源差异显著（p＜0.05）。 在益生菌抗病毒实验中，选用猪传染性胃肠炎病毒（Transmissible GastroenteritisCoronavirus，TGEV）作为病原体。TGEV的增殖与毒力测定，选择TGEV感染猪睾丸（ST）细胞，运用MTT比色法测定细胞活性，筛选出具有较强抗TGEV活性的菌株。研究结果显示猪源益生菌菌株抗TGEV的效果最好（p＜0.05），其次为鸡源益生菌，狐貉源益生菌抗猪源TGEV作用不显著。通过益生菌抗新城疫病毒（NDV）的血凝试验结果对照，证明鸡源益生菌对同源病毒（NDV）的抑制效果最强。 运用硫酸铁铵显色法测定益生菌菌悬液对高胆固醇培养基（MRS-CHOL）中胆固醇的降解率。实验结果表明猪源益生菌胆固醇降解率在1.54%～43.80%之间；鸡源益生菌胆固醇降解率为13.02%～25.79%；狐貉源益生菌胆固醇降解率在4.28%～16.28%。不同菌株、不同来源益生菌降解胆固醇能力差异显著。 益生菌抗氧化性实验中，选取稳定性较高的DPPH自由基作为清除对象，将菌液上清与DPPH乙醇溶液混匀后，在517nm处测定光密度值。结果表明异源益生菌在不同程度上具有清除DPPH自由基能力，平均清除能力为猪源＞鸡源＞狐貉源。 筛选出具有综合抗致病特性优势的菌株进行耐酸耐胆盐实验，选择耐受性最强的5株进行生化鉴定及16S rRNA鉴定。结果显示P9为罗伊氏乳杆菌，P13为食淀粉乳杆菌，P26、P47和C1均为枯草芽孢杆菌。 通过益生菌在上述几个方面的生物学特性研究中发现：相同动物来源益生菌组内不同菌株抗致病特性作用存在显著差异；不同动物来源益生菌组间抗致病特性作用也存在显著差异；由此推断益生菌株发挥抗病特性作用时存在来源特异性、种属特异性和菌株差异性，并且当益生菌来源同病毒来源一致时，抗病毒特性作用效果最为显著。

关键词： 间充质干细胞   C3H10T1/2细胞   细胞间粘附分子1   实验性自身免疫性甲状腺炎  

摘要： 目的： 1.构建重组逆转录病毒载体MIGR1-ICAM-1,探讨细胞间粘附分子1(Intercellular cell adhesion molecule-1, ICAM-1)基因转染对小鼠间充质干细胞(Mesenchymal Stem Cells, MSCs)生物学特性的影响。为进一步研究ICAM-1是否影响MSCs对自身免疫性甲状腺炎(Autoimmune Thyroiditis, AIT)体内治疗效果提供实验基础。 2.利用外源性甲状腺球蛋白免疫C57BL/6小鼠建立AIT的动物模型——实验性自身免疫性甲状腺炎(Experimental Autoimmune Thyroiditis, EAT),为下一步开展大规模体内实验提供稳定可靠的动物模型。 方法： 1.通过RT-PCR方法扩增获得小鼠脾细胞ICAM-1基因全长DNA,将其克隆至中间载体pMD19-T,行双酶切及DNA测序鉴定后,将ICAM-1基因连接至逆转录病毒载体MIGR1七,对重组载体MIGR1-ICAM-1进行双酶切、RT-PCR及DNA测序分析。 2.将获得的重组逆转录病毒质粒MIGR1-ICAM-1及空质粒MIGR1均加入包装质粒ECOS后分别转染人胚肾细胞(T293细胞),将获得携带ICAM-1基因的逆转录病毒MIGR1-ICAM-1及空载体逆转录病毒MIGR1,分别感染C3H10T1/2细胞,荧光倒置显微镜下观察荧光蛋白的表达, real-time PCR和流式细胞术检测ICAM-1在基因水平和蛋白水平的表达。同时检测三种细胞的形态、表型、生长特点及成脂成骨分化等一般生物学特性；并通过淋巴母细胞转化实验(Lymphocyte transformation test, LTT)及混合淋巴细胞反应实验(Mixed lymphocyte reaction, MLR)检测三种细胞的免疫学特性。 3.建立EAT动物模型,将5周龄雌性C57BL/6小鼠于第0d和第14d用猪甲状腺免疫球蛋白(Porcine Thyroglobuli, PTg)及弗氏佐剂(Freund's adjuvant, FA)进行两次免疫；于实验第28d眼球取血,测血清甲状腺球蛋白抗体(Thyroglobulin Antibody, TgAb)、甲状腺过氧化物酶抗体(Antithyroid Peroxidase Antibodies,TPOAb)、甲状腺微粒体抗体(Thyroid microsomal Autoantibody, TMAb)水平,并分离甲状腺组织行HE染色及组织病分析。 结果： 1.对重组载体MIGR1-ICAM-1双酶切和RT-PCR电泳均显示获得1700bpICAM-1目的基因片段；DNA测序结果显示与基因文库中的小鼠ICAM-1基因序列完全相同,且插入方向正确,从而证实成功构建重组逆转录病毒载体MIGR1-ICAM-1。 2.逆转录病毒感染C3H10T1/2细胞后,荧光倒置显微镜下可见绝大部分细胞表达绿色荧光；real-time PCR和流式细胞术分别在转录水平(相对表达量1625.82+119.42)和蛋白水平(表达量90.3%)证实ICAM-1在C3H10T1/2细胞中均有高表达,从而证明获得稳定过表达ICAM-1的间充质干细胞系C3H10T1/2(C3H10T1/2-MIGR1-ICAM-1/MSC)。 3.进一步对过表达ICAM-1的C3H10T1/2细胞的生长特性、诱导分化能力及免疫学功能进行研究,结果表明,过表达ICAM-1可使C3H10T1/2细胞(29.18±2.47)%处于S期,且倍增时间缩短。在成脂诱导分化中,C3H10T1/2-MIGR1-ICAM-1/MSC获得脂肪细胞数显著降低(12.18±3.83/孔),且脂滴变小；real-time PCR检测成脂分化关键转录因子C/EBPα和PPARy的表达均显著下调；同样,在成骨分化中,过表达ICAM-1可使C3H10T1/2成骨分化的碱性磷酸酶活性及矿化骨结节形成能力显著下降,关键转录因子Runx2和Osteocalcin在mRNA表达水平亦显著降低,提示过表达ICAM-1可显著降低MSCs的成脂和成骨分化能力。 4.利用淋巴母细胞转化实验(Lymphocyte transformation test, LTT)和混合淋巴细胞反应(Mixed lymphocyte reaction, MLR)对过表达ICAM-1的MSCs进行免疫功能检测,结果显示,在LTT体系中,当MSCs:T细胞分别为1：40和1：5时,C3H10T1/2-MIGR1-ICAM-1/MSC与对照组C3H10T1/2-MIGR1/MSC的cpm值分别为(1955.25±