Just John J, Schwager Josef, Weber Rudolf
Zoological Institute, Division of Cell and Developmental Biology, University of Bern, Sahlistrasse 8, CH-3012, Bern, Switzerland.
Wilehm Roux Arch Dev Biol. 1977 Dec;183(4):307-323. doi: 10.1007/BF00848460.
Electrophoretic separation of hemoglobins of normalXenopus laevis and of isogenic animals derived from female hybrids ofXenopus laevis×Xenopus gilli revealed 5-9 components in premetamorphic larvae, and 3-4 components in adult toads. InXenopus laevis the number of larval hemoglobin components showed considerable variation, but this variation was absent in isogenic tadpoles, suggesting a genetic basis for hemoglobin polymorphism in larvae.Electrophoretic separation of larval and adult hemoglobins at different concentrations of acrylamide and treatment of these solutions with mercaptoethanol revealed that larval hemoglobin components are charge isomers, whereas adult hemoglobin was found to contain a minor dimeric component.Estimation of hemoglobin components showed that the main increase in adult hemoglobin, i.e from 30-90% of total hemoglobin, occurs within 4 weeks after completion of metamorphosis. By incroporation ofH amino acids in vivo a switch to preferential synthesis of adult hemoglobin and a corresponding decrease in larval hemoglobin production could be demonstrated during early climax stages. This suggests that thyroid hormones are involved in the hemoglobin transition. Yet chemical inhibition of the larval thyroid by thiourea resulted in a delayed but complete hemoglobin transition without morphological transformation. It is concluded that hemoglobin transition and morphological transformation of theXenopus tadpole require different concentrations of thyroid hormones.
对正常非洲爪蟾以及源自非洲爪蟾×吉利爪蟾雌性杂种的同基因动物的血红蛋白进行电泳分离，结果显示，变态前幼虫中有5 - 9种成分，成年蟾蜍中有3 - 4种成分。在非洲爪蟾中，幼虫血红蛋白成分的数量有相当大的变化，但在同基因蝌蚪中没有这种变化，这表明幼虫血红蛋白多态性具有遗传基础。在不同丙烯酰胺浓度下对幼虫和成年血红蛋白进行电泳分离，并用巯基乙醇处理这些溶液，结果表明幼虫血红蛋白成分是电荷异构体，而成年血红蛋白含有一种次要的二聚体成分。血红蛋白成分的估计表明，成年血红蛋白的主要增加，即从总血红蛋白的30% - 90%，发生在变态完成后的4周内。通过在体内掺入H氨基酸，可以证明在早期高潮阶段会转向优先合成成年血红蛋白，并相应减少幼虫血红蛋白的产生。这表明甲状腺激素参与了血红蛋白的转变。然而，用硫脲对幼虫甲状腺进行化学抑制导致血红蛋白转变延迟但完全，且没有形态转变。得出的结论是，非洲爪蟾蝌蚪的血红蛋白转变和形态转变需要不同浓度的甲状腺激素。
