昆布多糖对氯化镉诱导斑马鱼骨骼发育毒性的改善作用

探讨不同浓度的昆布多糖对氯化镉诱导的斑马鱼骨骼发育毒性的改善作用。选用发育正常的72 hpf斑马鱼胚胎,加入100 μg/L浓度的氯化镉,同时加入不同浓度（25、50、100 μg/L）的昆布多糖。3 d后,用钙黄绿素进行染色2 h,在体视荧光显微镜下观察斑马鱼骨骼发育的情况,拍照并计算硬骨部分的荧光染色面积。结果显示,不同浓度的昆布多糖溶液对氯化镉诱导的骨骼发育毒性均呈现出一定的改善作用,且呈剂量依赖关系,100 μg/L浓度的昆布多糖溶液对斑马鱼骨骼发育的改善作用最显著,25 μg/L浓度作用最弱。研究结果表明,昆布多糖对氯化镉诱导的斑马鱼骨骼发育毒性具有明显的改善作用。     

斑马鱼3种胰蛋白酶原基因的克隆、序列分析及组织表达

 胰蛋白酶是丝氨酸蛋白酶类超家族成员之一,在动物蛋白消化中起着重要作用。为深入研究胰蛋白酶在鱼类中的蛋白结构和生理功能,利用RT-PCR和RACE方法,成功获得了斑马鱼3种胰蛋白酶原cDNA序列(zftry1a、zftry1b和zftry2)。结果表明,zftry1a和zftry1b均有242个氨基酸残基组成,其中包括15个氨基酸的信号肽和5个氨基酸(LDDDK)的激活肽。zftry2由247个氨基酸残基组成,其中包括15个氨基酸的信号肽和9个氨基酸(APLGDDDDK)的激活肽。氨基酸序列比对结果显示,三者具备胰蛋白酶原的保守结构特征,如含有催化三联体氨基酸(His-57、Asp-102和Ser-195),12个半胱氨酸,位于底物结合口袋底部Asp-189和口袋开口处的Gly-216、Gly-226等。进化树结果显示,斑马鱼zftry1a和zftry1b属于group I,为阴离子胰蛋白酶原;斑马鱼zftry2属于group II,为阳离子型胰蛋白酶原。RT-PCR结果显示,三者组织分布模式类似,且在肠中有最高表达量。这些结果为研究鱼类胰蛋白酶原的基因进化和功能以及进一步探讨鱼类消化生理的分子机制奠定了基础。     

铅和铬对鱼类联合毒性的研究

采用斑马鱼研究铅和铬共存的联合毒性。二价铅对斑马鱼的２４ｈ、４８ｈ和９６ｈ的半致死浓度分别为１７１、１５５和１４６ｍｇ／ｌ,六价铬对斑马鱼的２４ｈ、４８ｈ和９６ｈ的半致死浓度分别为１１２、６７和５０ｍｇ／ｌ。在浓度１∶１的情况下,铅和铬共存对斑马鱼２４ｈ、４８ｈ和９６ｈ的半致死浓度分别为３５、２９和２６ｍｇ／ｌ。根据Ｍａｒｋｉｎｇ的指数法求得２４ｈ、４８ｈ和９６ｈ的相加指数ＡＩ分别为０８９、０６１和０４３,皆大于零,表现为协同作用。     

KSHV编码vGPCR影响斑马鱼胚胎血管发育

卡波氏肉瘤相关疱疹病毒(KSHV)编码的G-蛋白偶联受体(v GPCR)是病毒致瘤蛋白,能够促使宿主血管增生以及肿瘤发生.本研究采用显微注射法将v GPCR基因导入单细胞期斑马鱼受精卵;利用形态学观察、RTPCR、血管生成定量分析和血管染色法分析v GPCR对斑马鱼胚胎早期发育的影响.实验结果表明:v GPCR对斑马鱼胚胎早期形态发育无明显影响,但能导致斑马鱼胚胎肠下静脉血管形态产生畸形.本研究首次表明斑马鱼能够成为v GPCR致病机理研究的模式生物.     

萘醌化合物对斑马鱼肝脏染色体损伤研究

 为进一步研究萘醌化合物对斑马鱼致毒机理,选取甲萘醌、阿托伐醌、布帕伐醌、2-羟基-1,4-萘醌和2-乙酰氧基-1,4-萘醌为研究对象,利用微核试验方法研究了这5种萘醌化合物对斑马鱼肝脏96 h内染色体的损伤情况.研究结果表明,这5种萘醌化合物对斑马鱼肝脏染色体均有不同程度的微核效应.其中以甲萘醌最为明显,2-乙酰氧基-1,4-萘醌微核效应最弱;且这5种萘醌化合物微核效应均呈现时间-效应与剂量-效应关系.说明萘醌化合物可在不同程度上引起斑马鱼染色体的损伤,具有一定的遗传毒性.     

DNA transposons in vertebrate functional genomics

Genome sequences of many model organisms of developmental or agricultural importance are becoming available. The tremendous amount of sequence data is fuelling the next phases of challenging research: annotating all genes with functional information, and devising new ways for the experimental manipulation of vertebrate genomes. Transposable elements are known to be efficient carriers of foreign DNA into cells. Notably, members of the Tc1/mariner and the hAT transposon families retain their high transpositional activities in species other than their hosts. Indeed, several of these elements have been successfully used for transgenesis and insertional mutagenesis, expanding our abilities in genome manipulations in vertebrate model organisms. Transposon-based genetic tools can help scientists to understand mechanisms of embryonic development and pathogenesis, and will likely contribute to successful human gene therapy. We discuss the possibilities of transposon-based techniques in functional genomics, and review the latest results achieved by the most active DNA transposons in vertebrates. We put emphasis on the evolution and regulation of members of the best-characterized and most widely used Tc1/mariner family.Received 8 June 2004; received after revision 26 October 2004; accepted 18 November 2004     

模式生物斑马鱼在心血管疾病研究中的应用

斑马鱼近年来被广泛地应用于医学研究中。斑马鱼个体小、养殖费用低廉、身体透明,及易于基因操作等优势,使其成为一种理想的模式生物。笔者综述了模式生物斑马鱼在心血管疾病研究中的应用。首先介绍了斑马鱼的心血管发育、心血管影像、相关遗传学技术及斑马鱼作为模式生物在心血管疾病研究中的优势与不足;然后通过总结既往的研究,重点阐述了斑马鱼在动脉粥样硬化、心律失常、心肌病、先天性心脏病、心力衰竭、心脏再生、炎症、动脉生成、血栓及心血管药物筛选等领域的应用进展。     

Somite-specific expression of a novel fibronectin variant FN3 is negatively regulated by SHH

Fibronectins (FNs) are major extracellular proteins in blood plasma and many tissues of vertebrates, and play important roles in adhesion, migration and differentiation of cells. We have identified a novel variant (FN3) of fibronectin in zebrafish. FN3 mRNA is abundant, as detected by whole-mount in situ hybridization, in the presomitic mesoderm and the newly formed somites, but less abundant in mature somites. Ectopic expression of Sonic Hedgehog (SHH) results in a decrease of FN3 expression, whereas the expression level of FN3 increases in the flh mutants that lack the notochord. Our results suggest that FN3 may be involved in the formation of somites, but during somite differentiation its expression needs to be downregulated by signals derived from the axial tissues.     

Generation of mutants with developmental defects in zebrafish by ENU mutagenesis

As a good model for studying early development of vertebrates, zebrafish (Danio rerio) is attracting more and more attention. Following ENU mutagenesis, 320 F2 families were established. Mutants, which showed defects in epiboly, axis, somite, head, and cardiac and blood systems, were identified by observing morphological changes in F3 embryos. So far, 35 mutant lines have been established, the majority of which showed anomalies in axis and somite formation. These mutant lines provide useful genetic resources for cloning of the mutant genes and for studying mechanisms of early development of vertebrate embryos.