RESUMO
Telomeres are essential for chromosome stability, but their functions at specific cell-cycle stages are unknown. Telomeres are now shown to have a role in chromosome separation during mitosis. In telomeric DNA mutants of Tetrahymena thermophila, created by expression of a telomerase RNA with an altered template sequence, division of the germline nucleus was severely delayed or blocked in anaphase. The mutant chromatids failed to separate completely at the midzone, becoming stretched to up to twice their normal length. These results suggest a physical block in mutant telomere separation.
Assuntos
Anáfase , Cromossomos/fisiologia , Telomerase/metabolismo , Telômero/fisiologia , Tetrahymena thermophila/citologia , Animais , Sequência de Bases , Cromátides/fisiologia , Cromossomos/ultraestrutura , DNA de Protozoário/genética , Micronúcleo Germinativo/ultraestrutura , Microscopia de Fluorescência , Índice Mitótico , Mutação , Fenótipo , RNA de Protozoário/genética , Sequências Repetitivas de Ácido Nucleico , Telomerase/genética , Telômero/genética , Moldes Genéticos , Tetrahymena thermophila/genética , Transformação GenéticaRESUMO
A requirement-adapted peripheral-venous parenteral nutrition was developed by exchanging the conventional carbohydrates like glucose, etc., for disaccharide maltose in combination with a fat emulsion (650 mosm/l; 2,000 kcal). In a clinical randomised study, we compared this nutrition regimen with a common requirement-adapted parenteral nutrition regimen, which was applicated by central-venous catheter (2,000 mosm/l; 2,000 kcal). All results, including the results of tracer-investigations with the strable isotope 13C-leucine, showed no metabolic difference between these two nutrition regimens.
