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关键词： ascidian embryo   Ets transcription factor   embryonic induction   FGF signaling   notochord formation   mesenchyme formation   neural induction  

摘要： In ascidian embryos, a fibroblast growth factor (FGF) signal induces notochord, mesenchyme, and brain formation. Although a conserved Ras/MAPK pathway is known to be involved in this signaling, the target transcription factor of this signaling cascade has remained unknown. We have isolated HrEts, an ascidian homolog of vertebrate Ets1 and Ets2, to elucidate the transcription factor involved in the FGF signaling pathway in embryos of the ascidian Halocynthia roretzi. Maternal mRNA of HrEts was detected throughout the entire egg cytoplasm and early embryos. Its zygotic expression started in several tissues, including the notochord and neural plate. Overexpression of HrEts mRNA did not affect the general organization of the tadpoles, but resulted in formation of excess sensory pigment cells. In contrast, suppression of HrEts function by morpholino antisense oligonucleotide resulted in severe abnormalities, similar to those of embryos in which the FGF signaling pathway was inhibited. Notochord-specific Brachyury expression at cleavage stage and notochord differentiation at the tailbud stage were abrogated. Formation of mesenchyme cells was also suppressed, and the mesenchyme precursors assumed muscle fate. In addition, expression of Otx in brain-lineage blastomeres was specifically suppressed. These results suggest that an Ets transcription factor, HrEts, is involved in signal transduction of FGF commonly in notochord, mesenchyme, and brain induction in ascidian embryos. (C) 2003 Elsevier Inc. All rights reserved.

关键词： 组织胚胎学   课程建设   医学形态学   医学教育   高等院校  

摘要： 近年来,高校课程的规范化建设正在蓬勃开展并不断深化.组织胚胎学作为医学形态学的基础课程,如何在新世纪从培养高素质、具有创新能力的人才需要出发,认真反思,大胆继承和扬弃,改进传统的教育方法和教学手段,不断改善教学条件,从而提高教学水平和教育质量已成当务之急.

关键词： 组织胚胎学   实验教学   实验器材   课堂教学   教学效果  

摘要： 作者通过积极添置完善实验器材，充分发挥显微投影在组织胚胎学实验教学中的作用，在具体的实验教学中，要求学生边看镜下图像边绘图，加深印象，促进理解，加强实验课课堂提问和多种形式的测验，针对不同专业不同层次的学生，因材施教、突出重点，获得了良好的实验教学效果。

关键词： 组织胚胎学   教学   医学基础   临床课程  

摘要： 组织胚胎学是医学教育的基础课,传统的教学方法既抽象又枯燥,老师难讲,学生也不容易听懂.如何最大限度地调动学生自学的积极性,从被动学习转为主动学习,是教改的核心问题[1].

关键词： 人体组织学   研究生   入学考试   自学参考资料   人体胚胎学   研究生   入学考试   自学参考资料  

关键词： 组织胚胎学   计算机   多媒体课件   研制   应用  

摘要： 组织胚胎学是基础医学的主干课题,属于形态学科,具有很强的直观性.传统的教学方法是老师借助黑板、挂图和模型在大教室对学生进行讲解,然后在实验室指导学生自己观察.

关键词： 《组织学与胚胎学实验指导》   素质教育   组织胚胎学   实验教学   教育理念  

摘要： 在教育理念从应试教育向素质教育转变的过程中,学生负担越来越重,而每一学科的学时则越来越少.组织胚胎学的教学也面临着同样的问题:内容多、学时少,教学效果不理想.

关键词： 专升本   组织胚胎学   教学改革   医学教育  

摘要： 专升本教学作为一种新的医学教育模式,目前在我国尚无统一的教学大纲、教学计划可循,其教材和教学内容的选择、课程的设置等诸方面正处在一个初步探索、不断尝试、逐步改进和完善的阶段.

关键词： medicinal plant   Papaveracea   somatic embryo  

摘要： Culture conditions are described for high frequency somatic embryogenesis and plant regeneration in petiole and leaf explant cultures and petiole-derived embryogenic cell suspension cultures of Hylomecon vernalis Max. Petiole explants formed embryogenic calluses at a frequency of 53% when cultured on B5 medium supplemented with 13.6 muM 2,4-dichlorophenoxyacetic acid (2,4-D) alone. Leaf explants formed embryogenic calluses at a frequency of 21% when cultured at a combination of 4.52 muM 2,4-D and 2.22 muM 6-benzyladenine. Cell suspension cultures were established with petiole-derived embryogenic calluses using liquid B5 medium with 4.52 muM 2,4-D. Upon plating onto B5 basal medium, cell suspension cultures produced numerous somatic embryos, which then developed into plantlets. Regenerated plantlets were transplanted to potting soil and grown to maturity in a greenhouse.

关键词： Bambara groundnut   Vigna subterranea   cytokinin   adventitious budding   direct organogenesis  

摘要： An efficient protocol has been developed for direct shoot organogenesis from embryo axes derived from mature seeds of two different landraces of Bambara groundnut. Multiple shoots were initiated on several media containing different concentrations and combinations of benzylaminopurine (BAP) or thidiazuron (TDZ). Efficient regeneration occurred when the embryo axes were first plated for 6 days on a medium containing high concentrations of BAP (1 mg/l) and alpha-naphthaleneacetic acid (NAA, 1 mg/l) and then cut transversely and transferred onto a medium containing 1.5 mg/l BAP. Shoot regeneration frequency was 100% and from five to eight shoots per explant were obtained. The importance of using embryo explants and cytokinins in the culture media, with respect to controlling the development of a highly organogenic system, was demonstrated. Histological studies revealed that proliferating buds originated directly from the superficial layers of the explants without an intermediate callus phase. The regenerated shoots were rooted on a medium containing 1 mg/l NAA and then transferred to the greenhouse. Flow cytometric analyses and chloroplast counts of guard cells suggested that the regenerants were diploid. All were morphologically normal and fertile. The short duration, high efficiency and low frequency of somaclonal variation of this system make it well suited for wider biotechnological applications of Bambara groundnut-a neglected and under-utilized crop.