不同部位角膜上皮细胞体外增殖性的对比研究

为观察角膜缘、角膜周连及角膜中央部上皮细胞体外增殖的规律，确定角膜干细胞以选取体外培养角膜上皮细胞的部位。应用溴代脱氧尿嘧啶（Ｂｒｄｕ，胸腺嘧啶的类似物）掺入ＤＮＡ合成，抗－Ｂｒｄｕ单克隆免疫荧光抗体记标记细胞法，在流式细胞仪（ＦＡＣＳｔａｒ＾ｐｌｎｓ）上检测体培养的每一代角膜中央部、周边部及角膜缘上皮细胞增殖的情况。结果显示从第一代开始，角膜缘→角膜周边→角膜中央部上皮细胞增殖率逐渐递减；角膜缘     

B－值随机变量序列尾和的重对数律

本文利用Ｌｅｄｏｕｘ和Ｔａｌａｇｒｘｎｄ的Ｉｓｏｐｅｒｉｍｅｔｒｉｃ方法，将尾和形式的Ｋｏｌｍｏｇｏｒｏｖ重对数律推广到Ｂ－值随机变量序列情形，进而得到一般形式Ｂ－值随机变量序列的尾和重对数律，同时对独立同分布Ｂ－值随机变量序列得到了配重尾和的重对数律。     

生长调节剂对香石竹茎尖诱导形成芽的影响

将香石竹的茎尖作为外植体，分别接种于添加不同量细胞分裂素（６－ＢＡ或ＫＴ）及生长素（ＮＡＡ）的ＭＳ琼脂培养基上，结果表明，培养基中如果只添加６－ＢＡ或ＫＴ，当两者浓度分别在（０．０１－０．５）ｍｇ／Ｌ和（０．０１－１）ｍｇ／Ｌ时，对芽的产生起促进作用；在大于０．５ｍｇ／Ｌ和１ｍｇ／Ｌ时，则抑制芽的产生，培养基中同时加入ＮＡＡ和６－ＢＡ或ＫＴ，在ＮＡＡＲ 最小于６－ＢＡ或ＮＡＡ和ＫＴ时，利于芽的形成     

BudR和CHM对花椰菜幼苗下胚轴根芽分化的抑制效应

研究ＤＮＡ生物合成抑制剂５－溴－２－脱氧尿嘧啶和蛋白质生物合成抑制剂放线菌酮对花椰菜幼苗下胚轴切段离体培养中器官分化的抑制作用，结果表明：１）ＢｕｄＲ和ＣＨＭ对根的分化有一定的抑制效应，达到一定浓度时，能造成根分化的停止。ＣＨＭ的抑制作用较明显而强烈，表明根的分化对蛋白质的依赖性高于核酸；２）ＢｕｄＲ和ＣＨＭ对芽的分化均有抑制作用，达到一定浓度时，能造成芽分化的停止；ＢｕｄＲ的抑制效应较ＣＨＭ的明     

用正交设计法筛选中华芦荟丛生芽诱导的最优培养基

用正交设计法考察了不同浓度的６－苄基腺嘌呤（６－ＢＡ）、萘乙酸（ＮＡＡ）和蔗糖对中华芦荟丛生芽诱导的影响,方差分析结果显示：糖对中华芦荟丛生芽诱导的影响最大,其次是６－ＢＡ,而ＮＡＡ影响最小。筛选出中华芦荟丛生芽诱导的最佳培养为ＭＳ＋２．０ｍｇ／Ｌ６－ＢＡ＋０．３ｍｇ／ＬＮＡＡ＋３０ｇ／Ｌ蔗糖。     

半夏组织培养中不同植物生长调节物质对形态发生的效应

半夏叶片、叶柄离体培养，探讨不同植物生长调节物质对其形态发生的效应。结果表明：ＮＡＡ、２，４－Ｄ有利于愈伤组织形成，且附加２，４－Ｄ形成愈伤组织最快；诱导率最高；ＮＡＡ和低浓度２，４－Ｄ有利于根分化，附加ＮＡＡ根生长最快，高浓度２，４＋６－ＢＡ或ＫＴ抑制根的形成，６－ＢＡ或ＫＴ有利于芽的分化，６－ＢＡ促进芽的分化效果显著。     

玉米芽尖培养和丛生芽发生

不同基因型的玉米芽尖分生组织在添加适宜浓度６－ＢＡ（６－苄基嘌呤）的改良ＭＳ培养基上，经过四周诱导培养和四周芽发育培养，获得高频率的丛生芽和再生植株，芽尖倍增数可达３～８芽／芽尖．通过比较试验，建立了利用玉米自交系芽尖分生组织的快速成苗培养体系，确立了诱导丛生芽发生的适宜培养条件和程序，其适宜６－ＢＡ浓度为９．０～１３．５μｍｏｌ／ｌ．芽尖倍增数因基因型的不同而有明显的差异     

银边红雀珊瑚(Pedilanthus tithymaloides(L) Poir.var.cuculatus Hort.)快速繁殖研究

顶芽或腋芽在添加６－苄基氨基嘌呤（６－ＢＡ）３ｐｐｍ和萘乙酸（ＮＡＡ）０．５ｐｐｍ的ＭＳ培养基培养３０ｄ，长４－６ｃｍ，腋芽３－７个。此时，将它们分切成单芽切段，围到添加６－ＢＡ２ｐｐｍ的ＭＳ培养基，继代培养周期２１ｄ，繁殖系数５－８。芽长２－３ｃｍ时用添加吲哚丁酸（ＩＢＡ）１ｐｐｍ的ＭＳ培养基进行生根培养，培养２１ｄ，生根率８７％，移载成活率９３％。     

无花果的组织培养

对影响无花果外植体不定芽诱导的四个因子进行了研究：不同器官、培养基的组成、外植体的预处理和不同的品种。细胞分裂素ＢＡ的效果优于ＫＴ。茎尖和茎段不定芽诱导培养基为ｍｇ·Ｌ￣（－１）（ＭＳ＋ＢＡ），叶片的分化以浓度８ｍｇ·Ｌ￣（－１）的ＢＡ效果最好。赤霉素（ＧＡ＿３）有助于芽的萌发和生长，浓度在０．５～１ｍｇ·Ｌ￣（－１）为宜。割取嫩枝插入１／２ＭＳ，附加１ＢＡ或ＮＡＡ１．０～２．０ｍｇ·Ｌ￣（－１）的生根培养基中，根原基诱导率９５％以上，移栽成活率９０％以上。     

水溶性环氧底漆的工艺及推广应用

通过ＭＩＬ－Ｐ－８５５８２Ｂ水溶性环氧底漆在Ｓ－９２尾斜梁铝合金、复合材料零部件上的应用，介绍了水深性环氧底漆的工艺及推广应用。     

Induction of cranial and posterior trunk neural crest by exogenous retinoic acid in zebrafish

Retinoic acid (RA) plays an important role in development of vertebrate embryos. We demonstrate impacts of exogenous RA on the formation of neural crest cells in zebrafish using specific neural crest markers sox9b and crestin. Treatment with all -trans RA at 10₋₇ mmol/L at 50% epiboly induces sox9b expression in the forebrain and crestin expression in the forebrain and midbrain, resulting in significant increase of pigment cells in the head derived from the cranial neural crest. In addition, RA treatment induces expression of sox9b and crestin in the caudal marginal cells of the neuroectoderm during early segmentation. Earlier commitment of these cells to the neural crest fate in the posterior margins leads to abnormal development of the posterior body, probably by preventing mingling of ventral derived and dorsal-derived cells during the formation of the tailbud.     

铜、汞和铅对斑马鱼仔鱼肝脏发育的影响

以肝脏绿色荧光转基因斑马鱼T3（lfabp:EGFP）为模型,研究水环境典型重金属污染物铜（CuCl2）、汞（HgCl2）和铅（Pb（Ac）2）在较低浓度暴露下对仔鱼（72~144 hpf）肝脏发育的影响。结果显示,各暴露组存活率均在95%以上;CuCl2和HgCl2在1 μmol/L时均能够引起鳔发育或充气异常;3种化合物均能够显著减小肝脏荧光面积和光密度。相同暴露浓度下,CuCl2抑制肝脏发育的能力强于Pb（Ac）2和HgCl2,但HgCl2在0.01 μmol/L时就能够显著抑制肝脏发育;CuCl2和Pb（Ac）2抑制lfabp表达量的能力强于HgCl2,且Pb（Ac）2在0.01 μmol/L时就能够显著抑制lfabp表达。结果表明,3种重金属化合物均能够显著抑制肝脏发育;转基因斑马鱼仔鱼可以作为检测环境污染物肝脏发育毒性的首选模型。     

Regulation of axon growth in vivo by activity-based competition

The formation of functional neural networks requires precise regulation of the growth and branching of the terminal arbors of axons, processes known to be influenced by early network electrical activity. Here we show that a rule of activity-based competition between neighbouring axons appears to govern the growth and branching of retinal ganglion cell (RGC) axon arbors in the developing optic tectum of zebrafish. Mosaic expression of an exogenous potassium channel or a dominant-negative SNARE protein was used to suppress electrical or neurosecretory activity in subsets of RGC axons. Imaging in vivo showed that these forms of activity suppression strongly inhibit both net growth and the formation of new branches by individually transfected RGC axon arbors. The inhibition is relieved when the activity of nearby 'competing' RGC axons is also suppressed. These results therefore identify a new form of activity-based competition rule that might be a key regulator of axon growth and branch initiation.     

Retinoic acid causes an anteroposterior transformation in the developing central nervous system

All-trans retinoic acid (RA) is well known as a biologically active form of vitamin A and a teratogen. The identification of nuclear receptors for this ligand suggests strongly that it is an endogenous signal molecule, and measurements of RA and teratogenic manipulations suggest further that RA is a morphogen specifying the anteroposterior axis during limb development. Besides the limb, RA and other retinoids affect development of other organs, including the central nervous system (CNS). None of these other effects has been investigated in detail. Our purpose here was to begin analysing the effects of RA on CNS development in Xenopus laevis. We find that RA acts on the developing CNS, transforming anterior neural tissue to a posterior neural specification. These and other findings raise the possibility that RA mediates an inductive interaction regulating anteroposterior differentiation within the CNS. Following recent reports implicating transforming growth factor-beta 2-like and fibroblast growth factor-like factors in mesoderm induction, this indicates that a different type of signal molecule (working through a nuclear receptor, not a plasma membrane receptor) might mediate inductive cell interactions during early embryonic development.     

芦荟大黄素对斑马鱼胚胎发育及运动行为学的毒性研究

以斑马鱼胚胎为模型,研究芦荟大黄素对胚胎发育和行为学的影响。结果显示,1.0 μg/mL及以上浓度的芦荟大黄素对斑马鱼胚胎有致死作用,随着浓度的增加和作用时间延长而增强。芦荟大黄素对斑马鱼胚胎的孵化过程有阻滞作用,1.0 μg/mL及以上浓度的芦荟大黄素使斑马鱼胚胎出现了卵黄延伸异常、发育迟缓和身体弯曲等畸形现象,但是对斑马鱼仔鱼的运动行为学无明显影响。本实验结果提示,临床应用芦荟大黄素治疗如孕妇这类特殊病人时,应充分考虑药物的剂量和用药时间。     

视黄酸对热带爪蟾胚胎致畸效应的表型特征

取典型的胚胎致畸剂——全反式视黄酸对热带爪蟾(Xenopus tropicalis)胚胎进行24,36和48 h暴露.结果表明,2,10和50 μg·L^-1视黄酸暴露对胚胎的存活率没有影响,对胚胎的生长和发育却有明显的抑制作用,并导致所有胚胎出现畸形现象,说明视黄酸对热带爪蟾胚胎具有极强的致畸性,同时显示了热带爪蟾胚胎对视黄酸的敏感性.视黄酸主要引起胚胎脑部缩小、眼睛色素减少、围心腔水肿和尾巴弯曲等多种畸形类型. 24,36和48 h后,暴露组脑部畸形指数和眼睛畸形指数较对照组均有明显增加,并表现出较好的浓度-效应关系,而时间-效应关系不明显,表明视黄酸对脑和眼部的影响主要发生在暴露的前24小时;48 h后尾部的畸形指数相对于24 h有明显的升高.将视黄酸导致的胚胎畸形类型与污染物三丁基锡对比,表明视黄酸致畸特征图谱在三丁基锡致畸机制的研究中有重要的参考价值.由此可见,有可能将FETAX实验发展为一种基于致畸机制的发育毒性检测方法.     

Repressor activity of Headless/Tcf3 is essential for vertebrate head formation

The vertebrate organizer can induce a complete body axis when transplanted to the ventral side of a host embryo by virtue of its distinct head and trunk inducing properties. Wingless/Wnt antagonists secreted by the organizer have been identified as head inducers. Their ectopic expression can promote head formation, whereas ectopic activation of Wnt signalling during early gastrulation blocks head formation. These observations suggest that the ability of head inducers to inhibit Wnt signalling during formation of anterior structures is what distinguishes them from trunk inducers that permit the operation of posteriorizing Wnt signals. Here we describe the zebrafish headless (hdl) mutant and show that its severe head defects are due to a mutation in T-cell factor-3 (Tcf3), a member of the Tcf/Lef family. Loss of Tcf3 function in the hdl mutant reveals that hdl represses Wnt target genes. We provide genetic evidence that a component of the Wnt signalling pathway is essential in vertebrate head formation and patterning.     

视黄酸对胃癌细胞恶性表型的影响

研究ｔ－ＲＡ对胃癌细胞的作用和探讨其作用机理．结果表明：１）ｔ－ＲＡ能够有效地抑制胃癌细胞的生长．２）ｔ－ＲＡ能够降低胃癌细胞在软琼脂中形成集落的能力．３）ｔ－ＲＡ能够降低胃癌细胞的粘附能力．４）ｔ－ＲＡ能够抑制胃癌细胞在裸鼠中形成肿瘤的能力．４）扫描电镜观察显示,经ｔ－ＲＡ处理后,胃癌细胞表面的微绒毛消失．以上结果表明,ｔ－ＲＡ对胃癌细胞的恶性表型有显著的抑制作用．ｔ－ＲＡ可能作为治疗胃癌的有效药物．