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关键词： 组织胚胎学   教学方法   讨论课   学习兴趣  

关键词： 核仁组织者区   胚胎发育   染色体   晶状体上皮细胞   先天性失明   小鼠胚胎   胚胎细胞   小鼠眼球   培养基   真核细胞  

ISBN: (纸本)7800209032

摘要： Eggs and embryos of the sea urchin Paracentrotus lividus were used as a model to study the effect at the cellular level of potential anti-mitotic compounds extracted from the diatom Thalassiosira rotula. Eggs and embryos incubated in a water-soluble diatom extract, corresponding to 5 x 10(6) and 10(7) cells ml(-1), were totally blocked (i.e. cell division was blocked) at the one-cell stage. At lower concentrations (2.5 and 1.25 x 10(6) cells ml(-1)), the first mitotic division was inhibited in 32 +/- 26% and 25 +/- 3.5% of the zygotes, respectively, demonstrating the dose-dependent effect of diatom extracts on sea urchin development. Immunofluorescence dyes, specific for DNA and alpha-tubulin subunits, were used to stain nuclei and microtubules in sea urchin embryos during various phases of development. Images with the confocal laser scanning microscope showed that tubulin was not organised in filaments at the sperm aster and cortex levels, and that the pronuclei were not fused in embryos incubated soon after fertilisation with water-soluble diatom extracts corresponding to 10(7) cells ml(-1). At lower diatom-extract concentrations (4 x 10(6) cells ml (-1)), fusion of the pronuclei occurred but the mitotic spindle was not formed. Microtubules were clearly de-polymerised and the chromatin appeared globular and compacted at the centre of the cell. A similar structure was observed for sea urchin embryos incubated with 0.1 mM colchicine, a potent anti-mitotic compound. When sea urchin embryos were incubated in water-soluble diatom extracts at different times prior to the first mitotic division, microtubules appeared de-polymerised at each step, from pronuclear fusion to telophase, and cell division was blocked. At the histological level, embryos incubated with 4 x 10(6) cells ml(-1) diatom extract showed nuclear fragmentation without cytokinesis. The possible use of sea urchin embryos as a bioassay to test for other unknown compounds with cytotoxic activity in phytoplan

关键词： Culicidae   Cysteine Proteinases   Egg Proteins   Enzyme Precursors   Larva   蚊科   半胱氨酸蛋白酶类   卵蛋白质类   酶前体   幼虫   Cathepsins   Enzyme Precursors   Cysteine Proteases   Proteases   Vitellins   Larva   Cathepsin B   Cysteine Endopeptidases   Egg Proteins  

摘要： Here we report identification of a novel member of the thiol protease superfamily in the yellow fever mosquito, Aedes aegypti. It is synthesized and secreted as a latent proenzyme in a sex-, stage-, and tissue-specific manner by the fat body, an insect metabolic tissue, of female mosquitoes during vitellogenesis in response to blood feeding. The secreted, hemolymph form of the enzyme is a large molecule, likely a hexamer, consisting of 44-kDa subunits. The deduced amino acid sequence of this 44-kDa precursor shares high similarity with cathepsin B but not with other mammalian cathepsins. We have named this mosquito enzyme vitellogenic cathepsin B (VCB). VCB decreases to 42 kDa after internalization by oocytes, In mature yolk bodies, VCB is located in the matrix surrounding the crystalline yolk protein, vitellin. At the onset of embryogenesis, VCB is further processed to 33 kDa. The embryo extract containing the 33-kDa VCB is active toward benzoyloxycarbonyl-Arg-Arg-para-nitroanilide, a cathepsin B-specific substrate, and degrades vitellogenin, the vitellin precursor. Both of these enzymatic activities are prevented by trans-epoxysuccinyl-L-leucylamido- (4-guanidino)butane (E-64), a thiol protease inhibitor. Furthermore, addition of the anti-VCB antibody to the embryonic extract prevented cleavage of vitellogenin, strongly indicating that the activated VCB is involved in embryonic degradation of vitellin.

关键词： 板栗   空苞   组织胚胎   营养物质  

摘要： 本文就当前我国板栗生产中出现的低产、低出籽率、高空苞率的突出问题展开了分析和理论探讨。从影响板栗产量的因素入手 ,就板栗空苞的形成机理从组织胚胎、营养物质、激素水平等多角度分析讨论、归纳。结果表明 ,空苞形成的机理主要是 :组织胚胎发育不健全 ,空苞发生时间主要在合子阶段和初生胚乳核 ;授粉受精不良 ,导致胚早期败育 ;硼素、磷素及激素平衡学说 ,说明了营养元素中的硼、磷对板栗空苞的形成起着至关重要的作用 ,并且 ,具有调节控制多种物质代谢和生理机能的激素及其平衡关系 ,对板栗空苞及性别分化有较大影响。文中还就克服和降低空苞形成提出了切实可行的对策 :加强营养和树体管理、调整雌雄花比例、选配授粉树和优良品种。

关键词： 阑尾   临床分析   治疗   解剖形态   异常   术中   先天性   困难   特点   组织胚胎学  

摘要： 先天性阑尾异常的临床分析，其形态位置变异各种各样，常给临床渗断和治疗带来困难。因此，外科医师掌握有关阑尾异常的解剖形态学特点及组织胚胎学原理，对于术中进行妥普处理，无疑是有所裨益的，本文综台有关资料作一介绍。

关键词： somatic embryo   adventitious bull   plant regeneration   Panax ginseng  

摘要： Cotyledon explants of Panax ginseng at various developmental stages were cultured I,on Murashige and Skoog (MS) medium with 0.5 mu M indole butyric acid and 8.8 mu M N-6-benzyladenine. Upon culturing of cotyledon explants from mature zygotic embryos, 34% of the explants formed somatic embryos, and 46% formed adventitious shoots. In the cotyledon explains from 1-wk old seedlings, embryos, and axis-like shoots and roots developed at a high frequency (79%) near the excised portion of the cotyledon base. The developmental pattern of embryo axis-like organ formation was structurally different from that of somatic embryos and adventitious shoots but similar to that of parts of the embryos axis of zygotic embryos . In the early stages of embryo axis-like organ formation, epicotyl-like shoot primordia were developed directly from the cotyledon base after 2 wk of culture: subsequently roots developed near the base of the epicotyl-like shoots and eventually generated into plantlets with both shoots and roots. The frequency of embryo asis-like organ formation rapidly declined as the growth of seedlings proceeded. In addition, the frequency of somatic embryo and adventitious bud formation rapidly declined with the age of the cotyledons. Plant regeneration via embryo axis-like ol gan formation might Lr a new pattern of morphogenesis in P. ginseng cotyledon culture.

摘要： Recent reports indicate that neuronal elements develop in early larval stages of some Gastropoda from the Pulmonata and Opisthobranchia prior to the appearance of any ganglia of the future adult central nervous system (CNS). The present study describes similar early neuronal elements in Crepidula fornicata. A posterior FMRFamide-like immunoreactive (LIR) cell with anteriorly projected fibers was observed in the trochophore stage. Additional FMRFamide-LIR and serotonin-LIR cells and fibers were found in the apical organ in the trochophore and early veliger stages. FMRFamide-LIR and serotonin-LIR projections to the velum and foot were also detected at this time. As the veliger developed, peripheral FMRFamide-LIR and later catecholaminergic cells were located in the foot region. Also during this stage, catecholaminergic cells and processes were observed near the mouth. In addition, this study tentatively identified the first serotonin- and FMRFamide-LIR cells and fibers within the developing ganglia of the adult CNS, which appeared in close proximity to the earlier developing elements. These observations are consistent with the hypothesis that, in addition to its presumed role in the control of larval behaviors, the larval nervous system guides the development of the adult CNS. Larvae from the class Bivalvia and other invertebrate phyla also have neuronal elements marked by the presence of FMRFamide, serotonin, and catecholamines, and, therefore, this study may provide additional insights into phylogenetic relationships of the Gastropoda with other representatives of the Mollusca and different invertebrate phyla.

关键词： 胚胎组织   声像图表现   子宫内   不规则阴道流血   中期妊娠   自然流产   新兴县   手术证实   药物流产后   广东省  

摘要： 总结本院手术证实为子宫内胚胎组织物残留63例的声像图表现.病人年龄20～26岁,其中发生于药物流产后28例,自然流产后18例,人工流产后15例,中期妊娠引产后2例.