Variations in Several Responses of HeLa Cells to X-Irradiation during the Division Cycle

摘要: Several responses of synchronized populations HeLa S3 cells were measured after irradiation with 220 kev x-rays at selected times during the division cycle. (1) Survival (colony-forming ability) is maximal when are irradiated in early post-mitotic (G1) and pre-mitotic (G2) phases cycle, minimal mitotic (M) late G1 or DNA synthetic (S) phases. (2) Markedly different growth patterns result from phases: (a) Prolongation interphase (division delay) rises progressively through remainder (b) Cells while mitosis not delayed that division, but succeeding delayed. (c) Persistence as metabolizing entities does depend on phase cycle which they irradiated. (3) Characteristic perturbations normal occur: M suffer a small delay onset S, slight prolongation depression rate synthesis; major occurs G2. show no essentially alteration duration G2 minimal. S an appreciable decreased shorter than delay.