黄花蒿腺毛状分泌腺的起源和发育

应用石蜡切片制片方法,研究了黄花蒿腺毛状分泌腺的起源和发育.结果表明,黄花蒿腺毛状分泌腺由叶原基表皮的1个细胞发育而来,该细胞经1次纵裂和1次横裂形成4个细胞,位于表皮内的2个细胞经1次纵裂形成4个基细胞,位于表皮外的2个细胞经3次横裂形成2个柄细胞和6个分泌细胞.成熟腺体由12个细胞构成,包括4个基细胞,2个柄细胞,6个分泌细胞.     

Embryonic and neoplastic cell surfaces: availability of receptors for concanavalin A and wheat germ agglutinin

Embryonic tissue cells dissociated with ethylenediaminetetraacetate are readily agglutinated by the carbohydrate-binding protein concanavalin A. In this property, they resemble transformed, neoplastic cells; and they differ from untransformed adult cells, which are agglutinated by concanavalin A only after their receptors are unmasked by proteolytic treatment. Receptor sites for wheat germ agglutinin are also present on the surface of embryonic cells, but in a masked form, as on untransformed adult culture cells; they can be unmasked by treatment of the cells with trypsin. Concanavalin A binding sites on embryonic cells may function in cell contact and cell organization during embryonic morphogenesis and differentiation and later become masked in adult cells. The unmasking of these sites in neoplastic cells may represent a return, in this respect, to a condition resembling that of embryonic cells and may be related to cell mobility associated with infiltration and metastasis.     

猪类胚胎生殖细胞体外诱导分化为神经细胞的研究

【目的】探讨猪类胚胎生殖细胞向神经细胞分化的潜能。【方法】采用性腺-中肾区基质细胞与猪原始生殖细胞共培养的方法得到猪类胚胎生殖细胞,通过直接分化的方法进行神经细胞定向诱导。【结果】（1）与小鼠成纤维细胞作为饲养层相比,性腺-中肾区基质细胞作为饲养层同样能够支持猪类胚胎生殖细胞生长,二者对猪类胚胎生殖细胞的增殖能力不存在显著影响;（2）猪类胚胎生殖细胞有较强的碱性磷酸酶活性,Q-PCR结果显示多能性基因Oct4、Sox2及Nanog表达,增殖能力呈现“S”型,即生长的潜伏期、对数期及平台期,猪类胚胎生殖细胞经体外悬浮培养能够形成拟胚体;（3）经过诱导猪类胚胎生殖细胞能够分化形成表达神经干细胞、神经元及神经胶质细胞标记物的多种神经细胞类型。【结论】从早期性腺中成功分离培养得到了猪类胚胎生殖细胞,通过简单、快速的神经细胞分化的诱导体系证实了猪类胚胎生殖细胞具有体外定向分化为多种神经谱系细胞的能力。     

Activation of gamma delta T cells in the primary immune response to Mycobacterium tuberculosis

Although the immunologic role of T cells bearing the conventional alpha beta T cell receptor (TCR) has been well characterized, little is known about the function of the population of T cells bearing the gamma delta TCR. Therefore, the role of gamma delta T cells in the immune response to Mycobacterium tuberculosis (MT) was investigated. The number of TCR gamma delta cells in the draining lymph nodes of mice immunized with MT was greatly increased in comparison with the number of TCR alpha beta cells. Three biochemically distinct gamma delta TCRs were detected. Analyses of cell cycle, of interleukin-2 receptor expression, and of interleukin-2 responsiveness showed that a large proportion of the gamma delta T cells were activated in vivo. TCR gamma delta cells responded to solubilized MT antigens in vitro but, in contrast to MT-specific alpha beta T cells, the response of gamma delta T cells to MT did not require major histocompatability complex class II recognition. These results provide an example of antigen-specific activation of gamma delta T cells in vivo and indicate that gamma delta T cells may have a distinct role in generating a primary immune response to certain microorganisms.     

诱导多能干细胞体外定向分化为雄性生殖细胞研究进展

诱导多能干细胞（induced pluripotent stem cells, iPS）是借助基因导入技术将某些转录因子导入人或动物的体细胞,使体细胞重编程而得到的多能性细胞。iPS细胞来源丰富,研究表明利用不同的载体诱导系统或不同的转录因子组合,多种体细胞都可被重编程为iPS细胞,如成纤维细胞、肝细胞、角质细胞及脐带血细胞等。作为干细胞中新的一员,iPS细胞在克隆形态、基因表达模式、表面标志物、拟胚体形成、畸胎瘤及嵌合体形成（小鼠）、分化能力等方面与胚胎干细胞（embryonic stem cell, ESC）非常相似。与胚胎干细胞一样,在特定的诱导条件下,iPS细胞在体外可被诱导分化为多种细胞,如心肌细胞、血细胞、生殖细胞等,进一步拉近了干细胞和临床疾病治疗的距离,iPS细胞也成为细胞治疗及组织器官再生最有前景的种子细胞,在细胞替代性治疗、发病机理研究及新药筛选方面具有潜在价值。雄性不育不仅影响人类正常健康生活,对畜牧业的发展也极为不利。国内外的研究成果表明,给予适当的诱导物及诱导条件,人和小鼠的iPS细胞体外可被诱导分化为原始生殖细胞（primordial germ cells, PGCs）、精子细胞及其前体细胞。这些研究不仅避免了胚胎干细胞研究领域存在的取材困难、免疫排斥和伦理道德等问题,还为揭示雄性生殖细胞的发育机制及研究雄性不育提供了较好的研究平台。由人iPS细胞诱导得到的雄性配子可为患者提供自身的雄性配子产生后代,避免了免疫排斥问题,为未来治疗雄性不育带来曙光。iPS细胞体外诱导分化技术对现代畜牧业发展也具有巨大的潜在应用价值,可进行转基因动物的生产。现从不同的诱导剂、不同的培养条件及iPS细胞体外诱导分化优势等方面,对iPS细胞体外定向诱导分化为雄性生殖细胞的研究进展及应用前景进行综述和展望。     

Suppression of antitumor immunity by stromal cells expressing fibroblast activation protein-alpha

The stromal microenvironment of tumors, which is a mixture of hematopoietic and mesenchymal cells, suppresses immune control of tumor growth. A stromal cell type that was first identified in human cancers expresses fibroblast activation protein-α (FAP). We created a transgenic mouse in which FAP-expressing cells can be ablated. Depletion of FAP-expressing cells, which made up only 2% of all tumor cells in established Lewis lung carcinomas, caused rapid hypoxic necrosis of both cancer and stromal cells in immunogenic tumors by a process involving interferon-γ and tumor necrosis factor-α. Depleting FAP-expressing cells in a subcutaneous model of pancreatic ductal adenocarcinoma also permitted immunological control of growth. Therefore, FAP-expressing cells are a nonredundant, immune-suppressive component of the tumor microenvironment.     

Multiple sclerosis: distribution of T cell subsets within active chronic lesions

The distribution of T cells and T cell subsets was examined within the human central nervous system in active lesions from seven patients with chronic multiple sclerosis. The monoclonal antibodies anti-T11, anti-T4, and anti-T8 were used to detect total (whole) T cells, helper T cells, and suppressor-cytotoxic T cells, respectively, and a monoclonal antibody against human Ia was used for macrophages and B cells. Lesion progression was associated with large numbers of T4+ cells at the lesion margin and these extended great distances into the adjacent normal-appearing white matter. T8+ cells were most commonly concentrated around the lesion margin and displayed a preferential perivascular distribution. Within the lesion center, only a few T cells were found. Ia+ macrophages were most numerous within the centers of active lesions and were always present in the adjacent normal white matter. The monoclonal antibodies to T cells did not cross-react with glial cells including oligodendrocytes. These results indicate that T4+ cells are actively involved in lesion extension and Ia+ cells, in demyelination.     

A stem cell molecular signature

Mechanisms regulating self-renewal and cell fate decisions in mammalian stem cells are poorly understood. We determined global gene expression profiles for mouse and human hematopoietic stem cells and other stages of the hematopoietic hierarchy. Murine and human hematopoietic stem cells share a number of expressed gene products, which define key conserved regulatory pathways in this developmental system. Moreover, in the mouse, a portion of the genetic program of hematopoietic stem cells is shared with embryonic and neural stem cells. This overlapping set of gene products represents a molecular signature of stem cells.     

Ultraviolet irradiation transforms C3H10T1/2 cells to a unique, suppressible phenotype

Transformation of C3H10T1/2 cells by exposure to ultraviolet (UV) irradiation followed by tetradecanoyl phorbol acetate (TPA) has been used as a model of two-stage carcinogenesis. However, cells cloned from UV-TPA-induced foci (UV-TDTx cells) had a unique phenotype. Cloned UV-TDTx cells appeared transformed in pure culture but were unable to form foci when cocultured with C3H10T1/2 cells. However, in the presence of TPA, UV-TDTx cells form foci in mixed culture with C3H10T1/2 cells. This phenotype was the only one observed for UV-TPA transformants. These data suggest that communal suppression of cell division is a discrete phenomenon that must be overcome as one step in the multistage process of transformation, and this protocol permits the routine isolation of transformed cells responsive to density-dependent growth suppression.     

Somatic cell mating and segregation in chimeric frogs

Both pentaploid and haploid cells were observed in a short-term culture of bone marrow of a diploid-triploid frog chimera. Apparently, diploid and triploid marrow cells fused to form "hybrid" pentaploid cells, which subsequently gave rise by somatic reduction to haploid daughter cells. The hybrid marrow cells and their haploid segregants are presumably at a selective disadvantage, as neither type of cell has been detected in the circulating blood of chimeric frogs.     

The edge cell, a possible intraspinal mechanoreceptor

In the lateral edge of the "white matter" in the lamprey spinal cord, there is a group of nerve cells referred to as edge cells. The results of a combined physiological, light microscopical, and electron microscopical study suggest that these cells serve as intraspinal mechanoreceptors. Edge cells are depolarized on stretch of the lateral margin of the spinal cord, and they have nestlike ramifications in this region oriented in a rostrocaudal plane. These cells exhibit a close structural similarity with the crayfish stretch receptor.     

Ethylene modulates stem cell division in the Arabidopsis thaliana root

The construction of multicellular organisms depends on stem cells-cells that can both regenerate and produce daughter cells that undergo differentiation. Here, we show that the gaseous messenger ethylene modulates cell division in the cells of the quiescent center, which act as a source of stem cells in the seedling root. The cells formed through these ethylene-induced divisions express quiescent center-specific genes and can repress differentiation of surrounding initial cells, showing that quiescence is not required for these cells to signal to adjacent stem cells. We propose that ethylene is part of a signaling pathway that modulates cell division in the quiescent center in the stem cell niche during the postembryonic development of the root system.     

Endothelial cells stimulate self-renewal and expand neurogenesis of neural stem cells

Neural stem cells are reported to lie in a vascular niche, but there is no direct evidence for a functional relationship between the stem cells and blood vessel component cells. We show that endothelial cells but not vascular smooth muscle cells release soluble factors that stimulate the self-renewal of neural stem cells, inhibit their differentiation, and enhance their neuron production. Both embryonic and adult neural stem cells respond, allowing extensive production of both projection neuron and interneuron types in vitro. Endothelial coculture stimulates neuroepithelial cell contact, activating Notch and Hes 1 to promote self-renewal. These findings identify endothelial cells as a critical component of the neural stem cell niche.     

Cell surface changes associated with cellular immune reactions in Drosophila

In Drosophila melanogaster a temperature-induced change in immune competence accompanies cell surface alterations that cause its blood cells to adhere and to encapsulate a parasite. At 29 degrees C the blood cells of the tumorous-lethal (Tuml) mutant show a high degree of immune competence and encapsulate the eggs of the parasitic wasp Leptopilina heterotoma. At 21 degrees C the blood cells are essentially immune incompetent. High percentages of lectin binding cells were found under conditions which potentiated cellular encapsulation responses. Some immune reactive blood cells did not bind lectin. The low percentages of lectin binding cells in susceptible hosts suggest that developing parasites alter the cell surface of the blood cells of immune reactive hosts.     

IGF-I对体外培养山羊卵泡颗粒细胞增殖与分化的影响

为弄清ＩＧＦ－Ｉ在山羊卵泡不同发育阶段对颗粒细胞增殖与分化的影响,分类采集山羊小腔和大腔卵泡颗粒细胞进行体培养,对培养后颗粒细胞的ＤＮＡ含量和孕酮分泌量进行测定。结果表明,ＩＧＦ－Ｉ对来源于大,小卵颗粒细胞的增殖与分化都有促进作用。     

Different B cell populations mediate early and late memory during an endogenous immune response

Memory B cells formed in response to microbial antigens provide immunity to later infections; however, the inability to detect rare endogenous antigen-specific cells limits current understanding of this process. Using an antigen-based technique to enrich these cells, we found that immunization with a model protein generated B memory cells that expressed isotype-switched immunoglobulins (swIg) or retained IgM. The more numerous IgM(+) cells were longer lived than the swIg(+) cells. However, swIg(+) memory cells dominated the secondary response because of the capacity to become activated in the presence of neutralizing serum immunoglobulin. Thus, we propose that memory relies on swIg(+) cells until they disappear and serum immunoglobulin falls to a low level, in which case memory resides with durable IgM(+) reserves.     

小白鼠乳腺上皮细胞的体外培养

本试验对小白鼠乳腺上皮细胞的原代培养方法进行了探索。胶原酶消化法和组织块种植法均可用于培养小白鼠原代乳腺细胞。胶原酶消化法容易得到均匀的乳腺细胞，且上皮细胞所占比例也比较高。组织块种植法不容易丢失、损伤上皮细胞，然而上皮细胞长出较晚，且占比例较低。结果表明，可结合组织块转移、胰蛋白酶消化纯化上皮细胞。     

Tripeptide structure of bursin, a selective B-cell-differentiating hormone of the bursa of fabricius

Differentiation of lymphoid precursor cells in a variety of species is induced by polypeptide hormones such as thymopoietin for T cells and bursin for B cells. In the present experiments, bursin isolated from the bursa of Fabricius of chicken was found to induce the phenotypic differentiation of mammalian and avian B precursor cells but not of T precursor cells in vitro. Similarly, bursin increased cyclic guanosine monophosphate in cells of the human B-cell line Daudi but not in cells of the human T-cell line CEM. These inducing properties of bursin are the reverse of the inducing properties of thymopoietin produced by the thymus and are appropriate to a physiological B-cell-inducing hormone. A tripeptide sequence (lysyl-histidyl-glycyl-amide) was determined for bursin and confirmed by synthesizing this proposed structure and demonstrating chemical identity of the natural and synthetic peptides. Similarity of biological action was indicated in induction assays by elevation of cyclic adenosine monophosphate and guanosine monophosphate in Daudi B cells but not in CEM T cells.     

Professional antigen-presentation function by human gammadelta T Cells

Human gammadelta T cells are considered to play a vital role in protective immunity through cytokine secretion and cytotoxic activity. We report that cells expressing the Vgamma2Vdelta2+-T cell receptor (Vdelta2+ T cells) also display principal characteristics of professional antigen-presenting cells such as dendritic cells. Thus, when activated, these cells efficiently processed and displayed antigens and provided co-stimulatory signals sufficient for strong induction of na?ve alphabeta T cell proliferation and differentiation. We suggest that, upon microbial activation, Vdelta2+ T cells participate in the induction of adaptive immune responses and that these cells may be a useful tool in vaccine development and immunotherapy.     

安淮山羊骨骼肌卫星细胞的分离培养与鉴定

为了分离得到安淮山羊骨骼肌卫星细胞,成功构建山羊骨骼肌卫星细胞系,为相关研究提供实验材料。以安淮山羊背最长肌肌肉组织为材料,采取胶原酶和胰蛋白酶结合的二步消化法,结合差速贴壁法纯化原代骨骼肌卫星细胞。对骨骼肌卫星细胞中特异性基因Pax7用免疫荧光染色法及PCR扩增加以鉴定。通过分离、纯化,得到纯度较高的山羊骨骼肌卫星细胞,其形态为圆形,折光性强。培养一段时间后密度增大,细胞呈梭型。所得骨骼肌卫星细胞生长状态良好,具有较为一致的生长方式和形态特点。经免疫荧光染色法以及PCR鉴定发现细胞系中有Pax7基因的表达。通过上述材料和方法,可获得较纯的山羊骨骼肌卫星细胞,并稳定传代。