Thesis (doctoral)--University of Lund, 1996. / Added t.p. with thesis statement inserted.

Thesis (doctoral)--University of Lund, 1996. / Added t.p. with thesis statement inserted.

No description available.

No description available.

Includes bibliographical references. / 2 v. : ill. ; 30 cm. / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / Describes the purification and characterization of human polyamine oxidases found in rectoplacental serum. / Thesis (Ph.D.)--University of Adelaide, Dept. of Paediatrics and Women's and Children's Hospital Dept. of Immunopathology, 1998

This thesis explores the reaction of primary amines with 1,2-dibromoethane and 1,3-dibromopropane as a one step synthesis of N,N"-disubstituted ethylenediamines, RNH- CH2CH2-NH-R, N,N"-disubstituted propanediamines, R-NH-CH2CH2CH2-NH-R and N-substituted azetidines RN[(CH2)3]. Unlike earlier approaches in the literature, this method circumvents the use of the highly toxic #-haloamines. The reaction can also be a convenient approach to N,N",N""-trisubstituted diethylenetriamines which form as byproducts in the synthesis of the ethylenediamines and are readily separated by distillation. The respective propylenetriamines were obtained in analogous fashion from 1,3-dibromopropane. The use of N,Nʼ,N”- trisubstituted triamines for the stabilization of low valent main group compounds was exemplified through the synthesis and structural characterization of a phosphenium salt. N,N'-disubstituted ethylenediamines, R-NH-CH2CH2-NH-R" bearing different substituents R are difficult to obtain and require multi-step protocols. This thesis describes their one step synthesis from aziridines and primary amines. The analogous 1,3-propandiamines were obtained from primary amines and azetidines. N-tert-Butylimidazol was obtained through thermolysis of 1,3-di-tertbutylimidazolium chloride and used as precursor for bis carbenes.

Thesis (Ph. D.)--University of Adelaide, Dept. of Paediatrics and Women's and Children's Hospital Dept. of Ummunopathology, 1998. / Includes bibliographical references.

Th. doct.--Chim. des matériaux--Lyon 1, 1993. / 1993 d'après la déclaration de dépôt légal. Notes bibliogr.

The speB gene of E. coli encodes agmatine ureohydrolase (AUH). AUH catalyses the hydrolysis of agmatine to urea and putrescine in a polyamine biosynthetic pathway. The plasmid pKA5, derived from an E. coli genomic library, was the source of a 2.97 kb restriction fragment containing the speB gene. Sequencing of this fragment revealed three intact open reading frames, ORF1 and ORF2 on one strand and ORF3 on the opposite strand, as well as a truncated open reading frame, ORF4, which terminated 92 kb upstream from ORF3. ORF2 and ORF3 were convergent, and overlapped by 85% of their sequence. ORF1 and ORF3 were separated by a sequence of two imperfect repeats containing four palindromes, three of which were overlapping. ORF3 represented the coding sequence of the speB gene. Two transcripts were detected from the speB gene: a shorter transcript, initiated 101 bp upstream from ORF3, and a polycistronic message, coding for ORF3 and ORF4. The short transcript was abundantly expressed when ORF4 sequences were deleted, but when ORF4 and its upstream sequences were present, the polycistronic message predominated and the amount of the monocistronic message was drastically reduced. The promoter producing the shorter transcript required only a -12 TATACT sequence for activity. Deletion of a 460 bp fragment comprising the 5'-region of ORF1 from a plasmid containing ORF1, ORF2 and speB reduced the activity of AUH by 83%. This fragment contained two divergently oriented promoters. The presence of ORF1 did not stimulate ß-galactosidase encoded by the speB promoter fused to lacΖ. Agmatine induced transcription from speB but not from the ORF4 nor the ORF1 promoters. cAMP caused an 88% reduction in the AUH activity of wild type E. coli K-12 but had no effect on the activity of plasmid encoded AUH. The activity of neither the speB nor the ORF4 promoters fused to lacΖ or phoA were influenced by cAMP; in contrast, the lacZ promoter fused to lacZ or phoA was stimulated by cAMP. Thus, the role of cAMP and CRP on speB expression is indirect and limited to a single copy state. / Ph. D.

The objective of this research was to identify specific mechanisms involved in the regulation of ornithine decarboxylase, the first enzyme in the polyamine biosynthetic pathway. Immunochemical techniques were used to study post-translational modifications of the ODC protein in relation to activity alterations. Initial experimentation showed that Chinese hamster cells maintained in a defined medium express an ODC protein stable to intracellular degradation. Treatment of these cells with exogenous ornithine or polyamines resulted in a rapid loss of enzyme activity, without detectable changes in the enzyme specific activity. The loss of enzyme activity was a result of accelerated ODC degradation, as determined by immunoprecipitation of pre-labeled protein. In addition, spermidine, but not ornithine, totally inhibited new ODC synthesis. The mechanism of accelerated ODC degradation was investigated and found to occur by an apparent novel mechanism. Degradation of ODC was both ubiquitin-independent and non-lysosomal, and there was also no detectable accumulation of a modified form of ODC protein. In addition, it was found that a component of protein synthesis is required for this process, as inhibitors (cycloheximide, emetine, puromycin) blocked polyamine-accelerated degradation. ODC cDNA was used to synthesize both ODC specific mRNA and protein using in vitro synthesis. These systems may allow the generation of sufficient quantities of material which can be used to recreate in vitro the specific components involved in polyamine inhibition of ODC synthesis and the protease(s) responsible for degradation. The major finding of this work is the direct demonstration that ODC is a stable intracellular protein in the absence of putrescine and spermidine depleted cells (Chapter 2). In addition, that degradation occurs by a novel mechanism, with a requirement for some component of protein synthesis (Chapter 3). Finally, these studies describe the in vitro production of ODC protein and mRNA, which should facilitate further studies of polyamine regulation of ODC degradation and synthesis (Chapter 4).