Title: RADIATION ANALYSIS OF CHROMOSOME DISCRETENESS IN THE AUTOREPRODUCTION PROCESS
Abstract:For solving the question of the fate of different types of chromosome fragments formed in irradiation, the colchicine mitosis method, in which the cells do not separate, was used. Sprouts of Crepis ca...For solving the question of the fate of different types of chromosome fragments formed in irradiation, the colchicine mitosis method, in which the cells do not separate, was used. Sprouts of Crepis capillaris, which has three pairs of very different chromosomes, were x-irradiated with 200 or 400 r and placed immediately in a 0.01% colchicine solution, and the metaphase was studied in acetocarmine preparations. The more prolonged the contact with colchicine, the greater was polyploidy of the cells; e.g., with 400 r and fixation 16 hr after irradiation, tetraploid cells were present, after 24 hr octoploid, and after 32 hr, 16-ploid. Analysis of the data shows the absence in the cells of the expected amount of fragments in a few cases, Z out of 345 after the first reproduction and 2 out of 51 after the second. This may indicate a difference in the rate of fragment formation after irradiation. However, in the polyploid cells resulting from the K mitosis, the absence of whole chromosomes was also noted, as was the loss of the discrete normal structure of chromosomes in the descendants of cells formed under the influence of colchicinc, and not irradiated. The process of destruction is connected withmore » the characteristics of the process of reconstruction of the nucleus in the telophase of the colchicine mitosis in which multinucleated cells result. In the subsequent interphase, lysis of some of the formed micronuclei takes place. It was concluded that any chromosome fragment down to microfragments is able to go through a normal nuclear cycle and autoreproduction to three full cycles. (TTT)« lessRead More
Publication Year: 1963
Publication Date: 1963-01-01
Language: en
Type: article
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Cited By Count: 1
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