title: Half-life of cytoplasmic rRNA and tRNA, of plastid rRNA and of uridine nucleotides in heterotrophically and photoorganotrophically grown cells of Euglena gracilis and its apoplastic mutant W3BUL.
abstract: 1. For Euglena gracilis half-life data were calculated according to Greenberg's equation (Nature 240, 102-104, 1972) using steady-state specific radioactivities determined for cyt-rRNA, cyt-tRNA and pl-rRNA. 2. For all RNAs equal half-lives were found of 45 and 38 hr, respectively, in heterotrophically and photoorganotrophically grown cells. 3. Using the decay analysis equal half-lives were found for cyt-rRNA, cyt-tRNA and pl-rRNA being 79, 43 and 60 hr, respectively, in heterotrophically and photoorganotrophically grown wild-type cells and the mutant W3BUL. 4. As suggested by the specific radioactivity of intracellular [3H]UMP compared to that of [3H]uracil fed, the remarkable differences between RNA half-lives determined for heterotrophically and photoorganotrophically grown wild-type cells, seem to be caused by a different extent of the de novo synthesis of UMP. 5. Reutilization of RNA breakdown products suggested by increased half-lives of RNAs in the decay analysis compared to those determined by Greenberg's equation seems to occur mainly in heterotrophically grown cells.
authors.affiliation: Institut für Biologie, Fachbereich Biochemie/Biotechnologie, Pflanzenbiochemische Abteilung, Halle/Saale, Fed. Rep. Germany.
authors.forename: U
authors.initials: U
authors.lastname: Karnahl
authors.forename: C
authors.initials: C
authors.lastname: Wasternack
mesh_terms: D000818:Animals; D003593:Cytoplasm / Q000378:metabolism; D005056:Euglena gracilis / Q000235:genetics / Q000378:metabolism*; D006207:Half-Life; D012335:RNA, Ribosomal / Q000378:metabolism*; D012343:RNA, Transfer / Q000378:metabolism*; D014498:Uracil / Q000378:metabolism; D014500:Uracil Nucleotides / Q000378:metabolism*; D014542:Uridine Monophosphate / Q000378:metabolism; D014544:Uridine Triphosphate / Q000378:metabolism
chemical_list: D012335:RNA, Ribosomal; D014500:Uracil Nucleotides; D014498:Uracil; D012343:RNA, Transfer; D014542:Uridine Monophosphate; D014544:Uridine Triphosphate