Thesis (Ph.D.)--York University, 2007. Graduate Programme in Biology. / Typescript. Includes bibliographical references (leaves 166-175). Also available on the Internet. MODE OF ACCESS via web browser by entering the following URL: http://gateway.proquest.com/openurl?url_ver=Z39.88-2004&res_dat=xri:pqdiss&rft_val_fmt=info:ofi/fmt:kev:mtx:dissertation&rft_dat=xri:pqdiss:NR39036

Thesis (Ph. D.)--University of Texas at Austin, 1999. / Vita. Includes bibliographical references (leaves 202-222). Available also in a digital version from Dissertation Abstracts.

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In order to clone the DNA repair gene of Aspergillus nidulans, uvsF$ sp-$ pyrG$ sp-$ strains were transformed with a genomic library in a plasmid vector that carried the pyr-4 gene of Neurospora which complements pyrG mutants of Aspergillus. Out of the several transformants obtained, four were like wild type. For rescuing plasmids, transformant DNA was digested with Bg/II and self ligated, and used for transformation of E. coli. Two types of plasmids were obtained; these two had a region in common ($<$1.0 kb) that was not a simple overlap and gave evidence for rearrangements. Surprisingly, only the plasmids with the larger insert of Aspergillus DNA were able to complement uvsF$ sp-$ in the secondary transformation. Northerns of polyA$ sp+$-enriched mRNA, probed with this plasmid, showed three bands. However, its subclone which spans the shared region hybridized to only one of them (1.0 kb). Two cDNA and five genomic clones were identified. The two cDNA clones though not identical, cross-hybridized. Three out of five genomic clones were identical. The cDNA hybridized to a short segment (2.2 kb) of one of the three types of genomic clones, locating the putative uvsF gene sequence.

The activity of Adenosine diphosphoribosyl transferase (ADPRT), the chromatin-bound enzyme which specifically catalyses the cleavage of oxidized NAD⁺ with the concomitant covalent attachment of the ADP-ribose moiety to acceptor proteins, was investigated in Polyoma Virus-Transformed (PyY) and Untransformed BHK21/C13 (BHK) cells. It was shown that ADPRT activity was consistently 2-4 fold higher in PyY cells than in BHK cells. The spectrum of (ADP-ribose)_n residues synthesised by the two cell types was very similar when analysed by hydroxyapatite column chromatography. Poly (ADP-ribose) Glycohydrolase activity in the two cell types was identical with 25-30% degradation of the poly(ADP-ribose) over a period of 90 minutes. DNA damage resulting from incubation with Deoxyribonuclease was reflected by an immediate increase in ADPRT activity and an increase in (ADP-ribose)_n chain length by both cell types. Polyamines which are present at high concentrations in rapidly dividing tissues were able to stimulate ADPRT activity both <i>in vitro</i> and <i>in vivo</i> in BHK and PyY cells. In general the average chain length of ADP-ribose residues synthesised remained unaltered. No significant increase in the level of DNA-strand breakage could be detected in the polyamine-treated cells. Depletion of the cellular polyamine levels resulted in stimulation of ADPRT activity, but there was no significant difference in the spectrum of (ADP-ribose)_n residues synthesised. Again no significant increase in the level of DNA-strand breaks could be detected in the polyamine-depleted cells. These results suggest that DNA-damage may not be the only means of regulating ADPRT activity and that polyamines may have a role to play in this regard <i>in vivo</i>.

Thesis (Ph. D.)--University of Hong Kong, 2007. / Also available online.

Thesis (M.S.)--Oregon State University, 2008. / Printout. Includes bibliographical references (leaves 75-76). Also available on the World Wide Web.

Thesis (M.S. in genetics and cell biology)--Washington State University, December 2008. / Title from PDF title page (viewed on Dec. 31, 2008). "School of Molecular Biosciences." Includes bibliographical references.