Del Pino Eugenia M, Alcocer Iliana, Grunz Horst
Pontificia Universidad Católica del Ecuador, Departamento de Ciencias Biológicas, Avenida 12 de Octubre entre Patria y Veintimilla, Apartado 17-01-2184, Quito, Ecuador.
Universität GH Essen, FB (Biologie) Abt. für Zoophysiologie, Universitätstr. 5, D-45117 Essen 1, Germany.
Dev Growth Differ. 1994 Feb;36(1):73-80. doi: 10.1111/j.1440-169X.1994.00073.x.
Urea was found in the capsular fluid that bathes Gastrotheca riobambae embryos during incubation in the maternal pouch. The urea concentration in this fluid is higher than in blood from the mother, indicating that urea is accumulated by the embryo during the period of maternal incubation. Gastrotheca tadpoles tolerate up to 500 mM urea with 86% survival after 24 hours and die in solutions of 0.5 mM ammonia. These findings suggest that urea plays a role in the adaptation of G. riobambae embryos to the conditions of water stress within the maternal pouch. To improve the in vitro culture conditions of early embryos taken from the maternal pouch, a saline solution that contains urea was designed (GRS). GRS plus 30 mM urea was used for the culture of cleavage to the neurula stage embryos of G. riobambae. During organogenesis, the urea concentration was raised to 60 mM. Early embryos of Xenopus laevis tolerate urea, and in addition, no inducing effects of urea have been detected in animal cap explants of Xenopus.
在母袋中孵化期间，在包裹着里奥班巴达尔文蛙胚胎的囊液中发现了尿素。这种液体中的尿素浓度高于母体血液中的尿素浓度，这表明胚胎在母体孵化期间积累了尿素。里奥班巴达尔文蛙蝌蚪能够耐受高达500 mM的尿素，24小时后存活率为86%，而在0.5 mM氨溶液中会死亡。这些发现表明，尿素在里奥班巴达尔文蛙胚胎适应母袋内水分胁迫条件中发挥作用。为了改善从母袋中取出的早期胚胎的体外培养条件，设计了一种含有尿素的盐溶液（GRS）。GRS加30 mM尿素用于里奥班巴达尔文蛙胚胎从卵裂期培养到神经胚期。在器官发生过程中，尿素浓度提高到60 mM。非洲爪蟾的早期胚胎能够耐受尿素，此外，在非洲爪蟾的动物帽外植体中未检测到尿素的诱导作用。
