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关键词： 组织学   形态学   显微镜   显微数码互动  

摘要： 论述了第二军医大学组织学与胚胎学教研室基于"显微数码互动"技术下,对《组织胚胎学》教学方法和模式的新探索,希望能为其他院校的组织学教学提供一定的参考。

关键词： 人体组织学   高等学校   教材   人体胚胎学  

ISBN: (纸本)9787541671593

摘要： 本书共分为组织学、胚胎学共两部分，主要内容包括：组织学概论、细胞、上皮组织、固有结缔组织、肌组织、神经组织等。

关键词： Embryo   Mammary   Mouse   Bead   Explant culture   Epistasis   Protocol  

摘要： The involvement of molecular mechanisms in a particular process such as embryonic mammary gland development, can be revealed by modulation of one or several factors that purportedly act in that process. If those factors or their inhibitors are soluble, their function can be tested by loading them onto small inert beads, which are then implanted in cultured explants of the tissue of interest, in this case embryonic flanks. We here describe a protocol for such experiments.

关键词： Conifer   Pluripotency   Histochemistry  

摘要： Araucaria angustifolia, the Brazilian pine, is an endangered native conifer with economic and ecological importance. The female cone develops seeds containing the zygotic embryo, which, at cotyledonary stage, shows well-developed meristems. Little is known about the structure of gymnosperm meristems. In the present work, the composition and morphological organization of Araucaria angustifolia shoot and root apical meristems were studied during embryo development, using histochemical and microscope analyses. Histochemical evaluation revealed the presence of cellulose within the cell wall, cells with the presence of total proteins that react with Coomassie Brilliant Blue, starch grains, and large nuclei with evident nucleoli in the cytoplasm. Scanning electron microscopy showed apical meristem surface morphology, and both scanning and transmission microscopy revealed a thin and irregular cell wall with plasmodesmata and within the cells, mitochondria, many vacuoles, lipid bodies, Golgi bodies, and many amyloplasts with endoplasmic reticulum surrounding them and large nuclei. Similar to angiosperm cells, A. angustifolia meristem cells exhibit pluripotent characteristics, such as apparatus for intercellular communication and differentiation.

关键词： Caryophyllales   Phytolaccaceae   Corbichonia   systematics  

摘要： Flower anatomy and embryology of Lophiocarpus polystachyus was studied, based on over one thousand slides left by Theo Eckardt and prepared from material of a wild source in South Africa chiefly in the 1970s. The all bisexual flowers of the polytelic inflorescences possess a well-developed nectary, are promoted on the abaxial side, have a perianth of five tepals, a 4-merous or, more rarely, by fusion of two adaxial stamens, 3-merous androecium, a somewhat stipitate, unilocular gynoecium of two fused carpels with one basally inserted ovule. Wall formation of the introrse and tetrasporangiate anther conforms to the Monocotyledonous type. Meiosis of the microsporocytes during which 9 bivalents are visible leads after simultaneous delimitation of the microspores to tetrahedral and decussate pollen tetrads. The tricolpate pollen is 3-celled when shed. The ovule is campylotropous, bitegmic and crassinucellate, as is common in the Centrospermae. Embryo sac development is of the monosporic, Polygonum type. Embryogenesis follows the Caryophyllad type of Johansen. The fruit is a 1-seeded drupe. The flower anatomy of Lophiocarpus confirms an affinity to the Phytolaccaceae s.l. and its distance from the Chenopodiaceae because of the missing gynophore in the latter. A comparison with the embryological data for Corbichonia does not corroborate an intimate relationship of the two genera.

关键词： adrenergic tone   cholinergic tone   embryo and fetus   hypoxia   reptile   gene expression  

摘要： Reptile embryos tolerate large decreases in the concentration of ambient oxygen. However, we do not fully understand the mechanisms that underlie embryonic cardiovascular short- or long-term responses to hypoxia in most species. We therefore measured cardiac growth and function in snapping turtle embryos incubated under normoxic (N21;21% O-2) or chronic hypoxic conditions (H10;10% O-2). We determined heart rate (f(H)) and mean arterial pressure (P-m) in acute normoxic (21% O-2) and acute hypoxic (10% O-2) conditions, as well as embryonic responses to cholinergic, adrenergic, and ganglionic pharmacological blockade. Compared with N21 embryos, chronic H10 embryos had smaller bodies and relatively larger hearts and were hypotensive, tachycardic, and following autonomic neural blockade showed reduced intrinsic f(H) at 90% of incubation. Unlike other reptile embryos, cholinergic and ganglionic receptor blockade both increased f(H). beta-Adrenergic receptor blockade with propranolol decreased f(H), and alpha-adrenergic blockade with phentolamine decreased P-m. We also measured cardiac mRNA expression. Cholinergic tone was reduced in H10 embryos, but cholinergic receptor (Chrm2) mRNA levels were unchanged. However, expression of adrenergic receptor mRNA (Adrb1, Adra1a, Adra2c) and growth factor mRNA (Igf1, Igf2, Igf2r, Pdgfb) was lowered in H10 embryos. Hypoxia altered the balance between cholinergic receptors, alpha-adrenoreceptor and beta-adrenoreceptor function, which was reflected in altered intrinsic f(H) and adrenergic receptor mRNA levels. This is the first study to link gene expression with morphological and cardioregulatory plasticity in a developing reptile embryo.

关键词： PTHrP   Mammary   Development   Embryonic   Breast   Wnt   Bmp  

摘要： Parathyroid Hormone related Protein (PTHrP) is a critical regulator of mammary gland morphogenesis in the mouse embryo. Loss of PTHrP, or its receptor, PTHR1, results in arrested mammary buds at day 15 of embryonic development (E15). In contrast, overexpression of PTHrP converts the ventral epidermis into hairless nipple skin. PTHrP signaling appears to be critical for mammary mesenchyme specification, which in turn maintains mammary epithelial identity, directs bud outgrowth, disrupts the male mammary rudiment and specifies the formation of the nipple. In the embryonic mammary bud, PTHrP exerts its effects on morphogenesis, in part, through epithelial-stromal crosstalk mediated by Wnt and BMP signaling. Recently, PTHLH has been identified as a strong candidate for a novel breast cancer susceptibility locus, although PTHrP's role in breast cancer has not been clearly defined. The effects of PTHrP on the growth of the embryonic mammary rudiment and its invasion into the dermis may, in turn, have connections to the role of PTHrP in breast cancer.

关键词： Coffea arabica   embryo-to-plant conversion   germination   histology   reserve compounds   scanning electron microscopy   seed   somatic embryogenesis   temporary immersion bioreactors   water characteristics  

摘要： In Coffea arabica L., the development of direct sowing of somatic embryos (SE) in planting substrate, with subsequent nursery production of plants, has promoted the industrialization of somatic embryogenesis. However, plant conversion rates are still low and require improvements to enhance the cost-effectiveness of commercial micropropagation. With the aim of improving plant regeneration from SE, we studied the morphological and histological criteria and water characteristics during germination and plant conversion of zygotic embryos (ZE) and SE. At the cotyledonary stage, SE produced in a 1 l RITA((R)) temporary immersion bioreactor (area 55.8 cm(2)) were morphologically similar in size (2-3 mm) but abnormal as compared with mature ZE. Protein and starch reserve levels were extremely low throughout germination and conversion to plantlets, while the water status remained steady [water content (WC) from 76 to 87%, Psi from -0.37 to -0.47 MPa, pressure potential from 0.69 to 0.24 MPa]. In ZE, spectacular hydration occurred during the first 3 weeks (WC from 37 to 75%;Psi from -6.24 to -1.0 MPa). Cotyledons remained undifferentiated for 10 weeks after sowing. Conversely, after only 3 weeks under germination conditions in a RITA((R)) bioreactor, spongy and palisade parenchyma and stomata formed in SE cotyledons. The ZE plant conversion was faster than that of SE (14 vs. 22 weeks) and more efficient (rates 96 vs. 55%), with much more substantial hypocotyl and cotyledon development. The use of a new 5 l MATIS((R)) bioreactor (area 355 cm(2)), designed especially to favor embryo dispersion and light transmittance to SE, markedly improved the embryo-to-plantlet conversion rate (91%). These results highlight the morphological heterogeneity and lack of protein reserves in SE at the beginning of the germination phase and marked differences in water characteristics. However, they also reveal high phenotypic plasticity, leading to a highly efficient plantlet conversion rate due t

关键词： Auxin   Embryo bilateral symmetry   Cotyledon development   Shoot apical meristem activity   HD-Zip III transcription factors   Arabidopsis  

摘要： The Arabidopsis genome encodes ten Homeodomain-Leucine zipper (HD-Zip) II proteins. ARABIDOPSIS THALIANA HOMEOBOX 2 (ATHB2), HOMEOBOX ARABIDOPSIS THALIANA 1 (HAT1), HAT2, HAT3 and ATHB4 are regulated by changes in the red/far red light ratio that induce shade avoidance in most of the angiosperms. Here, we show that progressive loss of HAT3, ATHB4 and ATHB2 activity causes developmental defects from embryogenesis onwards in white light. Cotyledon development and number are altered in hat3 athb4 embryos, and these defects correlate with changes in auxin distribution and response. athb2 gain-of-function mutation and ATHB2 expression driven by its promoter in hat3 athb4 result in significant attenuation of phenotypes, thus demonstrating that ATHB2 is functionally redundant to HAT3 and ATHB4. In analogy to loss-of-function mutations in HD-Zip III genes, loss of HAT3 and ATHB4 results in organ polarity defects, whereas triple hat3 athb4 athb2 mutants develop one or two radialized cotyledons and lack an active shoot apical meristem (SAM). Consistent with overlapping expression pattern of HD-Zip II and HD-Zip III gene family members, bilateral symmetry and SAM defects are enhanced when hat3 athb4 is combined with mutations in PHABULOSA (PHB), PHAVOLUTA (PHV) or REVOLUTA (REV). Finally, we show that ATHB2 is part of a complex regulatory circuit directly involving both HD-Zip II and HD-Zip III proteins. Taken together, our study provides evidence that a genetic system consisting of HD-Zip II and HD-Zip III genes cooperates in establishing bilateral symmetry and patterning along the adaxial-abaxial axis in the embryo as well as in controlling SAM activity.

关键词： 奶牛   胚胎质量   卵泡生长   奶产量   有机微量元素   繁殖性能  

摘要： 研究旨在评价补充有机微量元素对泌乳期奶牛繁殖机能的潜在影响。试验奶牛在干奶期集中饲养并随机分组,对照组(n=32)饲喂无机微量元素补充饲料,试验组(n=31)饲喂同等数量的有机锌、有机铜、有机锰以及有机钴替代一部分无机微量元素。微量元素添加到预混料中饲喂给对照组和试验组奶牛(100g/头·d)。干奶期奶牛(产犊前40～72d)通过智能饲喂系统饲喂1.8kg/头·d预混料颗粒,分别提供40%锌、26%锰、70%铜以及100%钴,泌乳期奶牛(分娩后69～116d)在全混合日粮中添加,分别提供22%锌、14%锰、40%铜以及100%钴。试验组奶牛在产后14周产量增加(P=0.047),乳中尿素氮含量增加(P=0.039),分娩到产后1个月间体重损失大于对照组(P=0.040),乳脂率下降(P=0.045),体况评分下降(P=0.048)。试验组在产后13周时产奶量有增高趋势(P=0.089),子宫内膜铁的含量(P=0.070)、产后1个月时体重损失(P=0.056)以及乳蛋白含率(P=0.064)都有增加的趋势。试验组对干物质采食量、奶牛健康、第一轮卵泡动力、第一轮黄体检测、胚胎质量、肝脏以及黄体中微量元素的含量没有影响(P>0.1)。直肠温度≥39℃的奶牛人工授精时受精率较低(P<0.001)。然而,对于已经受精的个体、胚胎成活率、胚胎质量、副精子数量以及胚胎细胞数不受温度的影响(P>0.1)。得出的结论是,用相等数量的有机微量元素(锌、锰、铜及钴)取代一部分无机微量元素补充到日粮中,在泌乳中期增加了奶牛产奶量,但是没有影响产后卵泡动力学、胚胎质量以及肝脏、黄体中微量元素的浓度。