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关键词： 膜联蛋白A5/分析   细胞凋亡   生物素化作用   原肠胚/化学   原肠胚/细胞学   组织细胞化学   显微镜检查   共焦   动物   鸡胚  

摘要： This study describes the use of biotinylated annexin V for the histochemical detection of apoptotic cells in cultured chicken embryos during,gastrulation. This method is based on the Ca2+-dependent binding of annexin V to phosphatidylserine, a negatively charged phospholipid, located at the inner leaflet of the cell membrane in living cells. However, in the early stages of apoptosis, phosphatidylserine is translocated to the outer layer of the cell membrane and can then be recognized by annexin V. Applying this method in cultured chicken embryos during gastrulation, we obtained labelling of apoptotic cells in the three germ layers. In the epiblast and mesoblast, labelling was predominantly present in the region lateral to the primitive streak. At the level of the germinal crescent, labelled cells were also found in the epiblast. Labelled cells in the deep layer, which is a heterogeneous tissue layer composed of endophyll, sickle endoblast and definitive endoblast, were rather scarce. The distribution of cells, as observed in this study after labelling with annexin V in light microscopy and confocal laser scanning microscopy, is consistent with distributions reported by other authors using other approaches and with our previous observations made with the TUNEL technique and by electron microscopy after fixation in a tannic acid-based fixative. The main advantages of this method over other more sophisticated methods is its easiness and rapidity of execution and the fact that both early and late stages of apoptosis are detected. (C) 1998 Chapman & Hall.

ISBN: (纸本)7810104292

关键词： beta-glucuronidase   histology   microprojectile acceleration   rice   transformation  

摘要： The histology and time course of hygromycin-resistant callus formation from bombarded, seed embryo scutellum-derived embryogenic nodular units (ENUs) were investigated in four japonica rice cultivars (Taipei309, IDSA6, IR47686, IRAT361) exhibiting contrasting amenabilies in a microprojectile-mediated transformation system. ENUs from the above genotypes collected at a stage considered suitable for bombardment, exhibited contrasted organization in their peripheral regions. This organization was found to influence the hygromycin concentration requested to stop ENU growth, along with the amenability of transformed cells to evolve into isolated, clonal, transgenic resistant calli, from the rest of the ENU. Organized globular proembryos located at the periphery of ENUs proved to be quite tolerant to antibiotic selection. They also developed in selective induction medium, irrespective of whether they had been sectorially transformed or not, and produced chimaeric or clonal, non-transgenic proliferations. In contrast, the presence of a single layer or small clusters of embryogenic cells at the periphery of the bombarded ENU, whose growth was fully inhibited under a selective regime, generally led to the formation of clonal transgenic calli. An average of 2.5, 4.3, and 3.2 hygromycin resistant calli were produced per responding ENU in Taipei 309, IDSA6 and IR47686, respectively. We obtained histological and molecular evidence that the hygromycin resistant calli arising from a single bombarded ENU may have been formed through independent transformation events. (C) 1998 Elsevier Science Ireland Ltd. Al rights reserved.

关键词： Animals   Arylamine N-Acetyltransferase/analysis   Arylamine N-Acetyltransferase/analysis   Central Nervous System/chemistry   Central Nervous System/embryology   Central Nervous System/pathology   Cerebellum/chemistry   Cerebellum/embryology   Cerebellum/pathology   Embryonic and Fetal Development   Female   Gestational Age   Immunohistochemistry   Immunohistochemistry   Mice   Mice, Inbred BALB C   Pregnancy   Spinal Cord/chemistry   Spinal Cord/embryology   Spinal Cord/pathology  

摘要： Arylamine N-acetyltransferases (NATs) are important in susceptibility to xenobiotic-induced disorders (e.g., drug-induced autoimmune disease, bladder cancer), but their role in endogenous metabolism is yet to be elucidated. The discovery that human NATL acts upon p-aminobenzoylgluatamate (p-ABG) to generate p-acetamidobenzoylglutamate (p-AABG), a major urinary metabolite of folic acid, suggests that human NAT1 may play a role in folic acid metabolism and hence in the normal development of the neural tube. In this study we examined the distribution of NAT in neuronal tissue from adult mice and embryos. Immunohistochemical staining of the adult mouse cerebellum revealed NAT2 (the mouse homologue of human NAT1) expression in the cell bodies and dendrites of Purkinje cells and in the neuroglia of the molecular layer. In embryos, NAT2 was detected in developing neuronal tissue on days 9.5, 11.5, and 13.5. It was expressed intensely in the neural tube around the time of closure. The level of expression subsequently declined in the neuroepithelium but increased in glial cells. In addition, NAT2 was detected in the developing heart and gut. These findings demonstrate that the embryo itself expresses an enzyme which is involved in the metabolism of folic acid, so that the role played by both mother and embryo must be considered when examining the role of folic acid in embryonic development. These findings imply that polymorphisms in NAT genes could play a role in determining susceptibility to neural tube defects (NTD) and orofacial clefting, developmental disorders which can be prevented by dietary administration of folic acid. Teratology 58:174-182, 1998. (C) 1998 Wiley-Liss, Inc.

关键词： CDFI   残留胚胎组织   清宫术  

关键词： 扬子鳄   物种   组织胚胎学   生理学  

摘要： 早在３０００年前，我国的甲骨文字就有关于扬子鳄的记载，但直到１８７９年才由福韦尔（Ｆａｕｖｅｌ）命名为Ａｌｉｇａｔｏｒｓｉｎｅｎｓｉｓ而公诸于世。有关扬于鳄的研究，开始于２０世纪７０年代，８０年代和９０年代先后在扬子鳄生态学、组织学、胚胎学等方面取得...

关键词： cell differentiation   determinants   primary mesenchyme cells   sea urchin   unequal cell division  

摘要： To clarify the distribution and behavior of the maternal factors that direct the differentiation of primary mesenchyme cells (PMC) in sea urchin embryos, unequal division was induced at the third cleavage with the treatment of dinitro-phenol (DNP), and the numbers of differentiated PMC were examined. The most surprising finding was that the number of PMC was considerably increased in some of the DNP-treated embryos. This increase in the number of PMC was suggested to be closely related to the size of the precocious micromeres formed at the 8-cell stage. By measuring both the size of the precocious micromeres and the number of PMC in individual embryos, it was suggested that almost all the descendants of the precocious micromeres differentiated into PMC, ii the volume was less than 26 pL (about three times the volume of normal micromeres). Cell tracing experiments ascertained that precocious micromeres with small volumes behave just like micromeres formed at the fourth cleavage in normal embryos. The obtained results indicated that the maternal factors present in sea urchin embryos can direct, at least, more than three times the number of PMC, and that the number of cell divisions of the PMC lineage is not strictly regulated.

摘要： To identify candidate cis-acting regulatory regions involved in regulation of the Msx2 gene in anterior limb mesenchyme and calvarial osteoblasts, DNase I hypersensitive sites (DHSs) from -6.1 kb to +8.4 kb relative to the translation start site of the chicken Msx2 gene were identified in anterior and posterior limb mesenchyme, calvarial osteoblasts, and embryonic fibroblasts. A total of 12 DHSs were detected. Except for the DHS in the basal promoter region, none of the other DHSs were present in all four tissues, suggesting that the chromatin structure in the Msx2 gene locus is differently organized in these four cell types. One DHS was unique to Msx2 expressing cells and a second site to nonexpressing cells. Anterior and posterior limb mesenchyme had similar patterns of DHSs that were much more complex than observed in calvarial osteoblasts possibly reflecting differences in the complexity of Msx2 regulation in these two tissues.

关键词： Animals   Cytoskeleton   Ectoderm   Gene Expression Regulation   Developmental   Homeodomain Proteins   Immunohistochemistry   Mesoderm   Microinjections   Microscopy   Fluorescence   Morphogenesis   Phenotype   RNA   Messenger   Research Support   U.S. Gov't   P.H.S.   Sea Urchins   Signal Transduction   Tissue Transplantation   Transcription   Genetic   Zygote  

摘要： The patterning of the mesoderm of the sea urchin embryo is a classical paradigm of epithelial mesenchymal interactions in organogenesis, yet Little is known of its molecular basis. Here we address the role of the homeobox gene, SpMsx, a member of the highly conserved Msx gene family, in this process. Msx genes have been shown to function in the dorsoventral patterning of the central nervous system in Drosophila and in a variety epithelial-mesenchymal interactions in vertebrates. We showed previously that the SpMsx gene is expressed during embryogenesis in a complex and dynamic pattern consistent with roles in the development of subpopulations of endoderm, mesoderm, and oral ectoderm. To perturb this pattern of expression and thus probe the function of SpMsx, we injected SpMsx mRNA into single-cell zygotes and monitored development morphologically and with a series of territory-specific molecular markers. RT-PCR analysis revealed that injected SpMsx transcripts persisted at least until the gastrula stage in amounts comparable to endogenous levels, injected embryos exhibited deficiencies in the organization of primary and secondary mesenchyme cells within the blastocoelic cavity, as well as abnormalities in spicule number and shape. Defects in the endoderm were also common, including reduced or absent archenterons. Micromere transplantation experiments revealed that the defects in skeletogenic mesenchyme patterning were non-cell autonomous, consistent with findings that cell- cell interactions between ectoderm and the progenitors of the skeletogenic mesenchyme, the primary mesenchyme cells (PMCs), are important both for PMC guidance and spicule morphogenesis. Our data, taken together with observations in other organisms on the role of Msx genes in embryonic signaling processes, particularly involving the BMP pathway, suggest that SpMsx may be a part of the mechanism by which the ectoderm influences both the arrangement of primary mesenchyme cells within the blastocoel

摘要： Eotaxin is a potent chemoattractant for eosinophils during inflammation and allergic reactions in the adult, but its role in the embryonic development of the hematopoietic system has not been examined. We report here that eotaxin and its receptor, CCR-3, are expressed by embryonic tissues responsible for blood development, such as fetal liver (FL), yolk sac (YS), and peripheral blood. We found that eotaxin acts synergistically with stem cell factor to accelerate the differentiation of embryonic mast cell progenitors, and this response can he suppressed by pertussis toxin, an inhibitor of chemokine-induced signaling through Gi, protein and chemotaxis. Eotaxin promotes the differentiation of fetal mast cell progenitors into differentiated mast cells as defined by the expression of mast cell specific proteases. Furthermore, in combination with stem cell factor (SCF), it promotes the growth of Mac-1(+) myeloid cells from Embryonic progenitors. These studies suggest that eotaxin may be involved in the growth of granulocytic progenitors and the differentiation and/or function of mast cells during embryogenesis and/or pathological conditions that induce high levels of eotaxin, such as allergic responses. (C) 1998 by The American Society of Hematology.