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关键词： hatchability   egg storage   embryo growth  

摘要： The hypothesis was tested that enhanced embryonic carbohydrate metabolism may enable embryos to survive egg storage effects. As lines of broiler breeders age, some lines resist detrimental effects of egg storage on embryonic survival, whereas others do not. Fertile eggs were obtained from two lines differing in storage ability. Eggs from each line by age group were stored for 1 or 14 d prior to setting. Eggs were distributed randomly into a single machine and incubated under standard conditions. Beginning at 17 d of incubation, immediately prior to the plateau stage in oxygen consumption, embryos from each of the treatment groups were sampled for BW, organ growth, glycogen concentration, and plasma glucose concentrations. Sampling continued through hatching. Plasma glucose concentrations increased significantly, and hepatic glycogen concentrations declined as embryos approached hatching. The rate at which glycogen was accrued into muscle and heart tissue displayed a significant three-way interaction among line, age, and storage. Embryos from the line that resisted storage mortality maintained greater glycogen concentrations in muscle and heart tissues than those from the line and age with diminished survival rates. It was concluded that embryonic survival rates differ following egg storage because of the ability of the embryo to accrue and maintain adequate carbohydrate for growth and function of vital demand tissues.

关键词： Xenopus laevis   Spemann organizer   head organizer   anterior endomesoderm   regional ESTs   expression pattern screen   head organizer-specific genes  

摘要： We describe here a systematic screen of an anterior endomesoderm (AEM) cDNA library to isolate novel genes which are expressed in the head organizer region. After removing clones which hybridized to labeled cDNA probes synthesized with total RNA from a trunk region of tailbud embryos, the 5' ends of 1039 randomly picked cDNA clones were sequenced to make expressed sequence tags (ESTs), which formed 754 tentative unique clusters. Those clusters were compared against public databases and classified according to similarities found to other genes and gene products. Of them, 151 clusters were identified as known Xenopus genes, including eight organizer-specific ones (5.3%). Gene expression pattern screening was performed for 198 unique clones, which were selected because they either have no known function or are predicted to be developmental regulators in other species. The screen revealed nine possible organizer-specific clones (4.5%), four of which appeared to be expressed in the head organizer region. Detailed expression analysis from gastrula to neurula stages showed that these four genes named crescent, P7E4 (homologous to human hypothetical genes), P8F7 (an unclassified gene), and P17F11 (homologous to human and Arabidopsis hypothetical genes) demarcate spatiotemporally distinct subregions of the AEM corresponding to the head organizer region. These results indicate that our screening strategy is effective in isolating novel region-specific genes. (C) 2001 Academic Press.

ISBN: (纸本)7810711768

关键词： zebrafish embryo   promoter   enhanced green fluorescent protein   neuron   reporter gene   transcription unit  

摘要： The gene encoding zebrafish brain-derived neurotrophic factor (BDNF) was cloned from a PAC genomic DNA library. The entire transcription unit was contained in two independently isolated clones that together encompass 120 kb of genomic DNA. The intron/exon organization of the zebrafish gene was found to be identical to that of the mammalian gene but only one promoter has so far been identified. The associated 5' exon is 67% identical to exon Ic of the rat BDNF gene. A search of the 5' flank of the cloned promoter for sequence similarities with known transcription factor binding sites revealed potential AP-1, CREB, and SP1 binding sites. Fusion constructs containing the cloned promoter and 1.7 kb of 5' flank and an enhanced green fluorescent protein reporter that becomes membrane-anchored were injected into 1-8 cell stage embryos. Expression was seen in notochord, muscle, epithelial and endothelial cells of the 1-day-old embryo in consonance with the endogenous gene. These results demonstrate that the cloned promoter mediates cell-specific expression. (C) 2001 Published by Elsevier Science Ltd. on behalf of ISDN.

关键词： CAI   组织胚胎学   教学法   教学手段  

摘要： 目的 :探讨 CAI在组织胚胎学教学中的作用 ,改革教学方法 ,提高教学质量。方法 :在两个护理中专班组织胚胎学的整个教学过程中分别使用 CAI教学法和传统教学法 ,并对两种教学方法的教学效果进行比较。结果 :与传统教学法比较 ,应用全程 CAI教学的班次 ,学生的学习兴趣提高 ,对知识的掌握程度提高 ,课堂教学质量督导组对授课的评价提高。结论 :全程 CAI教学有利于增加信息容量 ,有利于拓宽学生的知识面 。

关键词： mouse   trachea   bud formation   branching morphogenesis   mesenchyme-free culture   FGF   transferrin  

摘要： Embryonic mouse tracheal epithelium, which branches in an epithelial-mesenchymal recombination culture with bronchial mesenchyme, was cultured under mesenchyme-free conditions. When embedded in a basement-membrane-like matrix and cultured in a serum-free medium supplemented with fibroblast growth factor 1 (FGF1), the tracheal epithelium did not branch, whereas the bronchial epithelium underwent branching morphogenesis. When the medium was enriched with transferrin (Tf), bud formation was induced in the tracheal epithelium and some buds branched secondarily. FGF7 and FGF10, in cooperation with Tf, induced tracheal bud formation to the same extent as FGF1, although the optimum concentrations differed. A bromodeoxyuridine-labeling study comparing cultures with and without Tf showed no Tf-specific amplification of cell proliferation. A whole-mount in situ hybridization study of the expression of Bmp4 and Shh genes in explants of mesenchyme-free culture revealed that both genes were ubiquitously expressed and that expression did not correlate with bud formation. This expression pattern was different from the distally localized expression pattern observed in normal lung rudiments and in extratracheal buds induced by the recombined bronchial mesenchyme. These results suggest that both bronchial and tracheal bud formations were initiated without localized exposure of the epithelium to FGFs and were not accompanied by localized expression of Bmp4 and Shh in the epithelium. (C) 2001 Wiley-Liss, Inc.

关键词： gastrulation   PMC migration   RGDS receptor   sea urchin  

摘要： Immunoblotting using polyclonal antibodies (pAb) raised against an FR-1 receptor (FR-1 R), a 57 kDa Arg-Gly-Asp-Ser (RGDS)-binding protein, of the sand dollar Clypeaster japonicus showed that the pAb monospecifically bound to the protein. FR-1R was present in purified plasma membrane, suggesting that the protein is a membrane-bound protein. The molecular structure of FR-1 R did not change throughout the early embryogenesis, whereas its expression changed significantly during this period. FR-1 R was present in the cortex of unfertilized eggs and was then transferred to the hyaline layer soon after the fertilization. The hyaline layer retained FR-1 R immunoreactivity during early embryogenesis. FR-1 R appeared on the basal side of the ectoderm at the morula stage and was retained basolaterally, at least, to the early gastrula stage. In mesenchyme blastulae, FR-1R was also present on the surface of primary mesenchyme cells (PMC). FR-1 R was localized on the basal side of the ectoderm in early gastrulae, exclusively at the place where PMC formed ventrolateral aggregates, and at the apical tuft ectoderm. In vitro, PMC bound to FR-1R and its binding was inhibited in the presence of a synthetic RGDS peptide or the pAb. The pAb introduced into the blastocoele perturbed PMC migration and gastrulation. FR-1R was weakly recognized by antihuman integrin (35 subunit pAb.

关键词： Suppressor of Fused   split-hand/split-foot malformation   chromosome mapping   in situ hybridization  

摘要： The genes for human and mouse Suppressor of Fused (SU(FU)/Su(Fu)) in the Hedgehog signaling pathway were characterized and found to contain 12 exons. Human SU(FU) localized on chromosome 10q24-25 between the markers D10S192 and AFM183XB12. We detected three additional SU(FU) isoforms, two of which have lost their ability to interact with the transcription factor GLI1. Expression analysis using whole mount in situ hybridization revealed strong expression of Su(Fu) in various mouse embryonic tissues. SU(FU) was considered a candidate gene for the split-hand/split-foot malformation type 3 (SHFM3). However, no alterations in the SU(FU) gene were found in SHFM3 patients. (C) 2001 Federation of European Biochemical Societies. Published by Elsevier Science B.V. All rights reserved.

关键词： 解剖学   基础课   必修课   临床医学   教学录像   实习课   医学课程   组织学   组织胚胎学   大专  

摘要： 近两年来,我院对临床医学大专班的教学,从课程设置到教学时数都进行了较大的改革,解剖学作为医学生重要的一门基础课,改革首当其冲.原来的临床医学大专班的教学计划分配,解剖学(含系统解剖学、组织胚胎学、局部解剖学)共190 学时,而改革后的教学计划分配,解剖学共120学时,其中系统解剖学及组织胚胎学90 学时,局部解剖学30学时.计划学时减少了近三分之一,而教学目的及要求并未改变.如何执行新的教学计划,达到新的教学目的及要求,是摆在我们面前的一大课题.为此,在教学过程中,我们着重从以下几个方面进行了努力.　　……

关键词： 组织胚胎学   远程教学   计算机   多媒体   校园网   人体组织学  

摘要： 建立组织胚胎学教学资源库 ,应用计算机的多媒体技术将组织学和胚胎学的图像、声音、动画、视频及文本进行管理和应用。管理功能包括学生管理、教师管理、授课管理、试卷管理和考试管理。应用功能包括学生可以利用该资源库进行学习和计算机考试 ;教师可以利用该资源库进行组课、授课和删除课程 ;教研室主任和教务处的领导可以利用该资源库进行人工组卷、计算机组卷。