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关键词： 胰岛淀粉样多肽   生长抑素   胃肠道   胚胎   新生期  

摘要： 为探讨胚胎期及新生期大鼠胃肠道的胰岛淀粉样多肽（ＩＡＰＰ）与其他生物活性物质的关系，用免疫组织化学ＰＡＰ法，在相邻切片上分别显示第１５～２１ｄ大鼠胚胎及新生大鼠胃肠道的ＩＡＰＰ免疫反应性（ＩＲ）细胞和生长抑素（ＳＳ）ＩＲ细胞，观察了ＩＡＰＰ与ＳＳ在胚胎及新生大鼠胃肠道的定位分布。结果表明：第１５ｄ胚胎，胃肠道内未见ＩＡＰＰ－和ＳＳ－ＩＲ细胞。第１７ｄ胚胎，ＩＡＰＰ－与ＳＳ－ＩＲ细胞均很少，免疫染色较弱，着色较浅，免疫反应性细胞散布于分化未完全的肠上皮细胞间。胚胎１９ｄ，ＩＡＰＰ－和ＳＳ－ＩＲ细胞出现于胃和小肠，以十二指肠为多。胚胎第２１ｄ及新生期，胃肠道各段均可见到ＩＡＰＰ－和ＳＳ－ＩＲ细胞。经邻片比较证明，胚胎第１９ｄ始至新生期，十二指肠和空肠中部分ＩＡＰＰ－ＩＲ细胞与部分ＳＳ－ＩＲ细胞的定位相同，表明ＩＡＰＰ与ＳＳ在十二指肠和空肠Ｄ细胞中有共存。胃、回肠、结肠和直肠未见到ＩＡＰＰ与ＳＳ有细胞内共存的现象。

关键词： epicardium   subepicardial mesenchyme   epithelial-mesenchymal transition   coronary vessels   quail-chick chimeras  

摘要： It has been proposed that the subepicardial mesenchymal cells (SEMC) originate from the primitive epicardium and also from migration of extracardiac mesenchyme from the liver area. We have studied the possibility of an origin of SEMC through transformation of the proepicardial mesothelium, as well as the potential of the early proepicardium to generate epicardium and SEMC in quail-chick chimeras. The study was carried out in quail and chick embryos between HH16 and HH29 stages. Most proepicardial cells, mesothelial as well as mesenchymal, were cytokeratin and vimentin immunoreactive, suggesting a cytoskeletal shift from the epithelial to the mesenchymal type. Furthermore, we immunolocated, in the proepicardial mesothelium, three proteins specifically expressed during the endothelial-mesenchymal transition of the endocardial cushions, namely the JB3/fibrillin-associated antigen, the ES/130 protein and the smooth muscle cell alpha-actin. Grafts of proepicardial tissue from HH16-17 quail embryos into chick embryos of the same age originated large areas of donor-derived epicardium, including mesothelial, mesenchymal, and vascular cells. The donor-derived primitive epicardium showed segment-specific features, being squamous and adhered to the myocardium on the atrial wall and showing morphological signs of ingression in the atrioventricular groove and outflow tract. These morphological traits together with the distribution of vimentin, the ES/130 protein, and the JB3/fibrillin-associated antigen suggested a localized transformation of some epicardial mesothelial cells into mesenchyme. Most of the donor-derived cells, mesothelial and mesenchymal, showed the vascular marker QH1, which frequently colocalized with cytokeratin. Heterotopic grafts of quail splanehnopleura into the pericardial cavity of chick embryos originated a squamous, epicardial-like, cytokeratin-immunoreactive cell layer on the heart surface, as well as a few QH1(+) subepicardial and intramyocardial cells

关键词： ABA   somatic embryogenesis   L-glutamine   thidiazuron  

摘要： Embryogenic callus and somatic embryos were induced from cotyledonary explants of African marigold (Tagetes erecta L.). Cotyledons were first cultured on MS medium supplemented with 2.0 mg l(-1) 2,4-D and 0.2 mg l(-1) kinetin. After 5 weeks, calli were transferred to MS medium supplemented with 0.02 mg l(-1) thidiazuron where compact embryogenic callus developed. Friable embryogenic callus developed when the compact embryogenic callus was transferred to medium containing 2,4-D and subcultured every 2 weeks. Friable embryogenic callus has been maintained for more than 2 years without losing the capacity to generate embryos. Embryo development was obtained when friable embryogenic callus was transferred to MS medium supplemented with 3 mg l(-1) ABA and 60 g l(-1) sucrose. The addition of 10-30 mM L-glutamine improved embryo development.

关键词： embryonic development   progesterone   chicks   FSH   hormone receptors   oviducts   immunohistochemistry   poultry   fowls  

摘要： In this study we evaluated the histomorphology and ultrastructure of the oviduct of newly hatched chicks, as well as the immunohistochemical expression of progesterone receptor (PR) in this tissue after follicle-stimulating hormone (FSH) treatment on days 13, 15 and 17 of embryonic development. Results indicated a marked difference in the histology of the oviduct of newly hatched chicks treated with FSH. Magnum mucosa from these animals presented a pseudostratified epithelium with evaginations from the lumen into the epithelium and from the latter into the stroma beneath where tubular glands are formed. In contrast magnum mucosa from control animals presented columnar epithelium with no evaginations. In magnum epithelium FSH also induced the formation of cilia and microvilli projections into the lumen as well as an increase in the wall and lumen areas and in the density of nuclei per unit-area. PR immunoreactivity was only observed in the oviduct of FSH treated animals. PR was located in the nucleus of epithelial luminal cells, mucosal stromal cells and smooth muscle cells. These findings suggest that FSH induces an adequate hormonal milieu for the cytodifferentiation and PR gene expression in the chick oviduct.

关键词： lung   alveolar epithelium   trachea   epithelial-mesenchymal interactions   surfactant proteins  

摘要： Normal lung morphogenesis and cytodifferentiation require interactions between epithelium and mesenchyme, We have previously shown that distal lung mesenchyme (LgM) is capable of reprogramming tracheal epithelium (TrE) from day 13-14 rat fetuses to branch in a lung-like pattern and express a distal lung epithelial phenotype, In the present study, we have assessed the effects of tracheal mesenchyme (TrM) on branching and cytodifferentiation of distal lung epithelium (LgE), Tracheae and distal lung tips from day 13 rat fetuses were separated into purified epithelial and mesenchymal components, then recombined as homotypic (LgM + LgE or TrM + TrE) or heterotypic (LgM + TrE or TrM + LgE) recombinants and cultured for 5 days;unseparated lung tips and tracheae served as controls. Control lung tips, LgM + LgE, and LgM + TrE recombinants all branched in an identical pattern. Epithelial cells, including those from the induced TrE, contained abundant glycogen deposits and lamellar bodies, and expressed surfactant protein C (SP-C) mRNA. Trachea controls, and both TrM. + TrE, and TrM + LgE recombinants did not branch, but instead formed cysts. The epithelium contained ciliated and mucous secretory cells;importantly, no cells containing lamellar bodies were observed, nor was SP-C mRNA detected. Mucin immunostaining showed copious production of mucous in both LgE and TrE when recombined with TrM. These results demonstrate that epithelial differentiation in the recombinants appears to be wholly dependent on the type of mesenchyme used, and that the entire respiratory epithelium has significant plasticity in eventual phenotype at this stage in development, (C) 1998 Wiley-Liss,Inc.

关键词： collagenase   axonal guidance   pia   cell migration  

摘要： Bacterial collagenase was injected into the ventricular cavity of the optic tectum of chick and quail embryos. Histological examination up to 6 days after enzyme injection revealed that the collagenase disrupted the pial basal lamina, which was evident by the fragmented distribution of basal lamina proteins at the pial surface of the midbrain and the brainstem. Although the disrupted basal lamina was not reestablished at later stages of development, the pial basal lamina of the newly developing neuroepithelium in the caudal part of the tectum was continuous and intact. Western blot analysis showed that the collagenase digested collagens but spared noncollagenous proteins. The disruption of the pial basal lamina caused the neuroepithelial cells to retract their pial end feet and caused tectal axons to exit the brain tissue into the adjacent mesenchyme. The vertical migration of neuroblasts to the pial layers of the tectum was inhibited, leading to a disruption of the tectal histogenesis. In the developing optic pathways, retinal axons were misguided at the optic chiasma and terminated in the head mesenchyme instead of the tectum. None of the abnormalities in histogenesis and axonal pathways were observed when the basal lamina was disrupted at a later stage of embryonic development. The present experiments demonstrate that the pial basal lamina has an important function during brain morphogenesis in restricting axons to the brain, providing an anchoring of the neuroepithelial cells to the pial surface, and allowing the formation of a defined cytoarchitecture of the brain. (C) 1998 Wiley-Liss, Inc.

关键词： 苜蓿   体胚发生   乙烯   生物合成   MGBG  

摘要： 在苜蓿（ＭｅｄｉｃａｇｏｓａｔｉｖａＬ．）愈伤组织继代之初加入不同浓度的甲基乙二醛双（脒腙）（ＭＧＢＧ）（０．５，１，２ｍｍｏｌ／Ｌ），可不同程度地抑制愈伤组织及其后体胚诱导悬浮培养物的生长和体胚形成；若在体胚诱导阶段加入，则上述的抑制作用更为强烈。ＭＧＢＧ不但促进愈伤组织乙烯释放量、内源ＡＣＣ（１氨基环丙烷１羧酸）水平和ＡＣＣ合成酶活性，也促进体胚诱导悬浮培养物的ＡＣＣ水平及ＡＣＣ合成酶的活性，但降低体胚诱导悬浮培养物的ＭＡＣＣ（丙二酰ＡＣＣ）水平。ＭＧＢＧ对体胚诱导和培养物的生长的抑制作用与其上述的对ＡＣＣ和乙烯生成促进作用及降低ＡＣＣ转化成ＭＡＣＣ的效应有关。

关键词： fibrillin   avian embryos   JB3 antigen   extracellular matrix   somites   notochord   microfibrills   segmental plate   morphogenesis  

摘要： The monoclonal antibody JB3 was previously shown to react with a protein antigen present in the bilateral primitive heart-forming regions and septation-stage embryonic hearts;in addition, primary axial structures at primitive streak stages are JB3-immunopositive (Wunsch et al. [1994] Dev. Biol. 165:585-601). The JB3 antigen has an overlapping distribution pattern with fibrillin-1, and a similar molecular mass (Gallagher et al. [1993] Dev. Dyn. 196:70-78;Wunsch et al. [1994] Dev. Biol. 165:585-601). Here we present immunoblot and immunoprecipitation data showing that the JB3 antigen is secreted into tissue culture medium by day 10 chicken embryonic fibroblasts, from which it can be harvested using JB3-immunoaffinity chromatography. A single polypeptide (M-r = 350,000), which was not immunoreactive with an antibody to fibrillin-1, eluted from the affinity column. Mass spectroscopy peptide microsequencing determined the identity of the JB3 antigen to be an avian homologue of fibrillin-2. Live, whole-mounted, quail embryos were immunolabeled using a novel microinjection approach, and subsequently fixed. Laser scanning confocal microscopy indicated an elaborate scaffold of fibrillin-2 filaments encasing formed somites. At more caudal axial positions, discrete, punctate foci of immunofluorescent fibrillin-2 were observed;this pattern corresponded to the position of segmental plate mesoderm. Between segmental plate mesoderm and fully-formed somites, progressively longer filamentous assemblies of fibrillin-2 were observed, suggesting a developmental progression of fibrillin-2 fibril assembly across the somite-forming region of avian embryos. Extensive filaments of fibrillin-2 connect somites to the notochord. Similarly, fibrillin-2 connects the mesoderm associated with the anterior intestinal portal to the midline. Thus, fibrillin-2 fibrils are organized by a diverse group of cells of mesodermal or mesodermally derived mesenchymal origin. Fibrillin-2 microfilaments are asse

关键词： morphogenesis   somatic embryogenesis   organogenesis   histology   wheat   Triticum aestivum  

摘要： Callus Induced from immature embryos of wheat cv Kharchia 65 on Murashige and Skoog's medium containing 2.5 mg l(-1) 2,4-D was maintained in the regenerable state by subculturing every 5-6 weeks on medium supplemented with 2,4-D (2.5 mg l(-1)) and proline (10 mg l(-1)), Addition of proline helped maintain morphogenic competence for over four years. The regenerating callus was analysed histologically about one year after first induction. Both somatic embryogenesis and shoot organogenesis were seen in the same callus tissue that contained typical stages of somatic embryoid development and evidence for the de novo shoot bud formation.

关键词： 人体解剖学   中等专业教育   教材   人体组织学:人体胚胎学   中等专业教育   教材   人体胚胎学:人体组织学   中等专业教育   教材