title: Initiation of the synthesis of ribosomal ribonucleic acid precursor in different regions of frog (Rana pipiens) gastrulae.
mesh_terms: D000818:Animals; D001001:Anura; D004475:Ectoderm / Q000378:metabolism; D004625:Embryo, Nonmammalian / Q000378:metabolism*; D004707:Endoderm / Q000378:metabolism; D008715:Methionine / Q000378:metabolism; D012335:RNA, Ribosomal / Q000096:biosynthesis*; D011894:Rana pipiens; D014316:Tritium
chemical_list: D012335:RNA, Ribosomal; D014316:Tritium; D008715:Methionine