Studies on the susceptibility of ultraviolet irradiated BHK21 C13 cells to transformation by polyoma virus and some aspects of their radiobiology

Gormley, I. P (1969) Studies on the susceptibility of ultraviolet irradiated BHK21 C13 cells to transformation by polyoma virus and some aspects of their radiobiology. PhD thesis, University of Glasgow.

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The role played by virused end radiation in the etiology of cancer is reviewed. The isolation and properties of one tumour causing virus, polyoma virus, are described. When BHK21 C13 cells were irradiated with low does of ultraviolet light before infection with polyoma virus and enhancement of the transformation rate was observed. A two-fold rise in the proportion of transformed colonics to normal colonies was found was found after a radiation dose of 100 ergs/mm2. This irradiation dose was sufficient to lower the plating efficiency of the cells by approximately 45%. A method was developed by which the rise in the proportion of transformed cells could be more adequately observed. This method involved the delayed plating of irradiated, infected cells in agar suspension medium. BHK21 C13 cells which were irradiated up to 24 hour before infection with polyoma virus did not show loss of the transformation enhacement. No enhacement was observed, however, when the cells were irradiated four or more hours after infection. The irradiation doses used did not significantly affect the transforming ability of the virus particles. The results obtained when experiments were performed to test the effect ultraviolet radiation on the interferon synthesising capacity of the cells suggested that reduced synthesis of interferon was not the mechanism by which transformation enhancement occurred. Survival curves were determined for BHK21 C13 cells and two lined of polyoma virus transformed BHK21 C13 cells. The curved obtained were of the normal "C" form. The transformed cells were found to be more resistant to ultraviolet irradiation than the untransformed cells. All cell lines tested showed a greater resistance to ultraviolet irradiation when plated out for colony formation in the presence of mouse embryo feeder cells. Cycloheximide, and inhibitor of protein synthesis, did not significantly affect the survival curves. Photoreactivation of ultraviolet radiation induced damage could not be demonstrated in BHK21 C13 cells. Repair of ultraviolet radiation induced sublethal damage in BHK21 C13 cells was demonstrated by a split dose technique, although the expression of this repair was not observed until 8 hours after the initial irradiation. Transformation of BHK21 C13 cells by ultraviolet irradiation alone could not be demonstrated. The results are discussed with regard to a possible mechanism for the observed enhacement of transformation.

Item Type: Thesis (PhD)
Qualification Level: Doctoral
Additional Information: Adviser: G P Stoker
Keywords: Nuclear physics and radiation, Biophysics
Date of Award: 1969
Depositing User: Enlighten Team
Unique ID: glathesis:1969-72443
Copyright: Copyright of this thesis is held by the author.
Date Deposited: 24 May 2019 15:12
Last Modified: 24 May 2019 15:12

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