Ribonucleic acid base composition in the developing amphibian optic cup-lens system☆

[摘要] TheRNAbasecompositionofthedevelopingopticcup-lenssystemofRanapipiensembryoswasdetermined.ThetotalRNAwasextractedandhydrolyzedtoobtainitsmononucleotideconstituents.Afterthenucleotideshadbeenseparatedbymeansofhighvoltagepaperelectrophoresis,theyweremeasuredspectrophotometricallyandtheRNAbasecompositionwascalculated.Determinationswerecarriedoutontheembryonicpartsatstagesbeforeandduringinductionanddifferentiation.Atstagesbeforeandduringinduction(Shumwaystages13,15,and16)thepresumptiveopticcupregionsweredissectedoutforoneseriesofdeterminationsandthepresumptivelensregionsforasecondseries.Atlaterstages(stages18,20,and25),thepresumptiveopticcupandlenswerenotseparatedfromoneanotherandwereanalyzedtogether.Thebasecompositionsofthedissectedpartswereoftheribosomaltypeatstages13,15,16,and18;G+Cvaluesvariedbetween59%and66%.Atthesestagesnosignificantdifferenceseitherbetweenstagesorbetweenpartsweredetectedwiththemethodused.Thebasecompositionandbaseratiosoftheopticcuppluslensatstage20aresignificantlydifferentfromthoseofthesamepartsatstage25.Thereisalsoasignificantdifferencebetweenthebasecompositionandratiosoftheopticcuppluslensandthoseofthewholeembryoatstages20and25.TheRNApermilligramdryweightincreasesintheopticcuppluslensfromstage15to20.ThepossibilityisdiscussedthattheobservedincreaseinRNAandthechangeinRNAbasecompositionmaybeduetosynthesisofspecificribosomes.

[学科分类] 生物科学（综合）