Application of Xenopus laevis in ecotoxicology (I)——Introduction and quality control of laboratory animal

According to WHO statistics, 80% of human dis- eases are related to environmental pollution[1,2]. Espe- cially in recent years, there are increasing reports onendocrine disorder, reproductive dysfunction, sexual reversal, ecoenvironmental deterioration, b…     

野木瓜注射液对爪蟾坐骨神经传导的影响

野木瓜注射液（Ｉｎｊｅｃｔｉｏｎｓｔａｕｎｔｏｎｉａｅ，ＩＳ）涂布于脊爪蟾（ＸｅｎｏｐｕｓＬａｅｖｉｓ）坐骨神经４ｍｍ长的一段上．电刺激跗部皮肤，记录半膜肌肌电．１０％ＩＳ使肌电的潜伏期和问期分别延长（１．５１±１．１５）ｍｓ和（２６．６±１６．１）ｍｓ（Ｐ＜０．０１，ｎ＝９）；５０％ＩＳ则使潜伏期延长（２．８４±２．１８）ｍｓ和幅度下降到原来的０．２１±０．２６（Ｐ＜０．０１，ｎ＝７）．ＩＳ对神经传导的阻滞作用是量效关系，给药８ｍｉｎ后电刺激坐骨神经干能使已受５０％ＩＳ影响而刺激跗部皮肤几乎不再引起肌电的半膜肌产生同对照一样的肌电．这表明在给药期内５０％ＩＳ主要阻滞传入纤维的传导，而不影响传出纤维的功能．     

运用爪蟾变态实验检测镉的甲状腺激素干扰效应

将NF51阶段非洲爪蟾(Xenopus laevis)蝌蚪暴露于Cd2+浓度为0.01,0.1和1mg.L-1的溶液中21d,观测Cd2+对爪蟾的生长、变态和甲状腺组织结构的影响.1mg.L-1Cd2+暴露组爪蟾蝌蚪与对照组相比,7d后,平均体重减少了0.39倍,体长和后肢长分别减少了0.17倍和0.27倍,发育阶段稍有延缓;21d后,1mg.L-1Cd2+暴露组爪蟾蝌蚪后肢长减小了0.11倍,延缓了1个发育阶段.其余各浓度组在7d和21d暴露后,体重、体长、后肢长和发育阶段与对照组无显著差异.21d后,Cd2+各浓度组甲状腺组织结构出现滤泡数目减少、胶质减少甚至空泡化等现象,1mg.L-1Cd2+暴露组甲状腺滤泡之间还出现溶通现象.结果表明CdCl2具有甲状腺激素干扰效应,并可能是由于该化合物直接作用于甲状腺组织引起.由此可见,爪蟾变态实验可以有效检测重金属盐的甲状腺激素干扰效应.     

黄角苔叶绿体rbcL基因编码区的序列分析

测定了黄角苔（Ｐｈａｅｏｃｅｒｏｓｌａｅｖｉｓ（Ｌ．）Ｐｒｏｓｋ）叶绿体ｒｂｃＬ基因编码区的１３９８个核苷酸序列,并且由此推导出对应的氨基酸序列．此基因中密码子的第２和第３位上Ａ／Ｔ所占的比例较高,分别为５３６％和７７５％．黄角苔ｒｂｃＬ基因的编码区与花旗松、菠菜、玉米和雷氏衣藻间在核苷酸序列上的同源性分别为８４０％,８１５％,７９３％和７６３％;在氨基酸序列上的同源性分别为９１．０％,８９．９％,８８．５％和８９．３％．为研究角苔植物的系统发育提供了核苷酸序列方面的资料．     

抗爪蟾角蛋白单克隆抗体的研究

本实验以非洲爪蟾(Xenopus laevis)成体皮肤角蛋白免疫的BALB/c鼠脾细胞与小鼠Sp2/0骨髓瘤细胞在PEG的作用下进行融合,经HAT选择培养、ELISA筛选、反复克隆化及冻存复苏,获得四株稳定分泌抗体的杂交瘤细胞株。对其中一株杂交瘤细胞KD_(10)及其分泌的抗体进行了较全面的研究。     

非洲爪蟾卵母细胞内的螺旋钙波和靶波

该文应用定态线性化的Atri模型方程，描述非洲爪蟾(Xenopus Laevis)卵母细胞内钙波的生成和演化。在忽略细胞边界影响的近似下，得到了爪蟾卵母细胞内螺旋钙波和靶波的解析解。对于远离细胞中心的渐近情形，对应的螺旋波为Archimede型。由此得到的波速、波长和周期均与实验和数值模拟结果吻合。并指出IP3R失活常数必须大于2．43s，才能产生胞内周期钙波。     

Specific degradation of keratin in Xenopus laevis egg extracts undergoing apoptosis

Cytochrome c activates apoptosis specific protease XCPP32 when being added to Xenopus laevis egg extracts, and induces apoptosis in this cell-free system. During apoptosis, cyto-skeleton proteins in egg extracts are degraded. Western blot assay indicates that 42-ku acidic keratin in egg extracts has been degraded by XCPP32. The degradation of 42-ku keratin may be crucial in apoptosis.     

Application of Xenopus laevis in ecotoxicology (I)—Introduction and quality control of laboratory animal

The aim of the series of papers is to discuss the application of Xenopus laevis, as model animal in biology, in ecotoxicology. X. laevis as model animal is wildly used in biological study and has provided a lot of relating data because of many advantages, such as living in water and being easily maintained, laying eggs in the whole year, and externally fertilizing and developing. Embryos and larvae of X. laevis like other amphibians are directly exposed in the aquatic environment and sensitive to pollutants. In addition, sex differentiation and sex organ development of X. laevis are sensitive to sex hormones and endocrine disruptors with sex hormone activities, which enable X. laevis to be used in studies on sex hormone disruption and reproductive toxicity of endocrine disruptors. Metamorphic development of X. laevis is very sensitive to thyroid hormones and thyroid disruptors, which enables X. laevis to be used for evaluating thyroid disruptors. Also, X. laevis ecotoxicology can be linked with amphibian population declines and malformed frog occurrence, being one of the hotspots in ecology. Thus, more and more laboratories have introduced X. laevis to ecotoxicological study. The quality of laboratory animals correlates with scientificity and reliability of results from animal experiments. It is especially important for toxicology. Quality control of X. laevis involving several factors such as water and food is discussed in this paper.