. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. 170 R. P. ELINSON ET AL before insertion into the pouch, helps in the clean sepa- ration of pouch tissue from embryos. Segmenting eggs and early embryos of G. riobambae die in saline solutions of low ionic strength (, 10% MBS), but survive in full strength MBS or other amphib- ian salines. Advanced embryos (del Pino/Escobar stages 20-25) survive in solutions of high and low ionic strength (del Pino ct 1975). The tolerance of advanced embryos to low salt concentration is a preparation for the free- living tadpole st
. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. 170 R. P. ELINSON ET AL before insertion into the pouch, helps in the clean sepa- ration of pouch tissue from embryos. Segmenting eggs and early embryos of G. riobambae die in saline solutions of low ionic strength (, 10% MBS), but survive in full strength MBS or other amphib- ian salines. Advanced embryos (del Pino/Escobar stages 20-25) survive in solutions of high and low ionic strength (del Pino ct 1975). The tolerance of advanced embryos to low salt concentration is a preparation for the free- living tadpole stages. For //; vitro culture, segmenting eggs and early embryos are placed in 5% Ficoll in an amphibian saline. Embryos at the onset of cleavage have been cultured for 20 days in a tissue culture well filled with the above solution. Ficoll prevents swelling, which occurs in saline solutions and which inhibits gastrulation and leads to bursting. Cultur- ing in Ficoll permits observations of blast ula and gastrula stages. Successful culture of cleavage stage embryos was also accomplished by placing embryos in MBS after re- moving them from the pouch and transferring them to 2-ml wells of disposable tissue culture plates with a 10 /ul drop of MBS. The amount of liquid around the embryo should be very small. The well is then filled with mineral oil. Once or twice a week, embryos are washed in a large dish with MBS to retard fungal growth, although it is easy to damage embryos during manipulation. Embryos can be cultured in this way for 2 to 4 weeks. We recommend using Ficoll in amphibian saline and incubation in ml without changing the medium. Advanced embryos (del Pino/Escobar stages 20-25) hatch from the jelly capsule quite easily. For culture, em- bryos are placed in a petri dish with full strength MBS. 10% MBS or tap water. The jelly capsule breaks, bell gills are resorbed into the peribranchial cavity, and embryos begin to swim as tadpoles. Embryonic growth in culture alw
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Keywords: ., bookauthorlilliefrankrat, booksubjectbiology, booksubjectzoology
