No description available.

There is no abstract available for this dissertation. / Human Performance Laboratory

In plants, 3-hydroxy-3-methylglutaryl coenzyme A reductase (HMGR, EC 1.1.1.34) is a key enzyme regulating biosynthesis of phytosterols, plant growth regulators, carotenoids, antimicrobial defense compounds, and numerous other isoprenoids. To initiate molecular studies of HMGR in relation to defense responses in plants, we utilized yeast HMGR cDNA sequences to isolate tomato genomic sequences encoding HMGR. The nucleic acid sequence and gene structure was determined. The tomato HMGR gene (HMG2) contains four exons separated by three introns and encodes a polypeptide of 602 amino acid residues (about 64,714 Da). Two membrane-spanning regions are contained in the NH₂-terminus of the HMGR polypeptide. The COOH-terminus shares significant homology with HMGR sequences from different species. Genomic Southern hybridization analyses reveals that tomato contains 3 to 4 HMGR genes. The HMGz2 gene cross-hybridizes to mRNA of about 2.7 kb which is highly induced in tomato cells treated with fungal elicitors and in stems, leaves, or roots stressed by wounding suggesting that the HMGz2 is a defense-related gene in tomato. Hybridization with a gene specific probe indicates that the HMG2 gene is induced specifically during defense responses and is distinct from the gene(s) expressed during fruit development and ripening. / Ph. D.

Submitted in partial compliance with the requirements for the Master’s Degree in Technology, Department of Homoeopathy, Durban University of Technology, Durban, South Africa, 2015. / INTRODUCTION Homoeopathy is based on the law of similars meaning the medicine that produces symptoms in a healthy individual will cure the same symptoms in a sick individual (Sankaran, 1991:5). AIM Conducting a proving on Ubiquinone 30CH will lead to an establishment of its therapeutic potential through the application of the law of similars thus adding to the Materia Medica and advancing Homoeopathy (Vithoulkas, 2002). It was hypothesised that the 30CH potency of Ubiquinone would clearly produce observable signs and symptoms in healthy prover’s. It was further hypothesised that a comparison of Ubiquinone to those remedies yielding the highest numerical value and total number of rubrics on repertorisation of the proving symptoms would elucidate differences and similarities between Ubiquinone and other Homoeopathic remedies to clarify its therapeutic indications. It was hypothesised that in this manner a better understanding of Ubiquinone and its relationship to other Homoeopathic remedies would be gained. Methodology The proving of Ubiquinone 30CH was a randomised, double blind placebo controlled study, using the 30th centesimal potency and a total of 26 participants who met the inclusion criteria. Each prover was provided with a journal to record their symptoms daily. The data extracted from the journals were added to the case histories and physical examinations to compile a proving profile. The identity of the substance was revealed and the information was correlated after completion of the proving. The symptoms found were translated into Materia Medica and repertory language. Once the proving was concluded, a comparison to the remedies yielding the highest numerical value and total number of rubrics on repertorisation - which is the technique of using a repertory to identify the Homoeopathic medicines whose Materia Medica corresponds most closely to the clinical picture of the patient and from amongst which a simillimum may be chosen (Swayne, 2000:183) - was compared to the proving symptoms. Results The remedy’s main influence was on the mental and physical state. The most prominent symptoms seen in the mental sphere were extreme irritability and exhaustion. There was a sense of emotional fragility with a desire to be alone. On the physical side, headaches were common and weakening pains of the extremities were experienced. It can be concluded that the 30CH potency of Ubiquinone, if used precisely according to Homoeopathic principles, can be applied to a clinical setting, as the extensive range of symptoms produced during the proving suggests an equally wide array of application of the remedy Ubiquinone. Conclusion One of the downfalls of Homoeopathy is the limited number of provings being done, (Vithoulkas, 2002). Vithoulkas (2002:143) maintains that in order for Homoeopathy to advance, it is necessary to perform provings on new substances to expand the Homoeopathic armamentarium. Increasing the number of remedies in the Materia Medica facilitates greater accuracy and individualisation when treating patients (Wright, 1999). According to Herrick (1998) numerous cases cannot be solved because many of the most important remedies have not yet been developed. The purpose of this study was to increase the knowledge of drug substances due to the limited amount of information in our current Materia Medicas, by investigating the therapeutic potential of Ubiquinone 30CH. The investigation supported the hypothesis that Ubiquinone would produce clearly observable signs and symptoms in healthy volunteers. It is essential that the proving symptoms be verified and expanded through clinical use and with further proving of Ubiquinone in various potencies so that it becomes a well utilised remedy in the future.

published_or_final_version / Medicine / Master / Master of Research in Medicine

clk-1 encodes an enzyme involved in the biosynthesis of ubiquinone (UQ), a redox active lipid that is found in all cellular membranes, including in the mitochondrial respiratory chain. In the nematode Caenorhabditis elegans clk-1 mutants display slow and deregulated physiological rates, including slow embryonic and post-embryonic development, retarded germline development, slow behaviours, and an increased lifespan. clk-1 slow germline development phenotype was previously linked to clk-1 altered ROS metabolism and its effect on lipid oxidization and the let-60/ras pathway. I have taken a genetic suppressor approach to further investigate the causes of the slow germline development phenotype of the clk-1 mutants. / Through this approach one mutant that suppresses the germline phenotype of clk-1 was identified. This suppressor, gsc-1(qm216), restored clk-1 germline development to slightly faster rates than wild type worms. This effect was specific to clk-1 and gsc-1 did not speed germline development rates in wild type worms. Furthermore, this effect appeared to be additive to lowering cholesterol levels but not to increasing cytoplasmic ROS levels. gsc-1 by itself appeared to have a deleterious effect on brood size and to increase lifespan. Neither of these effects were additive to the clk-1 phenotype and were therefore believed to affect similar mechanisms. The genetic mapping of gsc-1 precisely located the mutation to the center of chromosome II and linked it tightly to the lin-5 mutation. However, none of the transgenic lines managed to complement the gsc-1 mutation and its identity was not discovered. / In addition, to determine the role of reactive oxygen species (ROS) in the Clk phenotype, I have been analyzing all clk mutants (clk-1 to -10), by increasing ROS levels through the disruption of sod-1 and sod-2 genes, and scoring Clk phenotypes. I found that, although several clk mutants appear to have altered ROS levels, the phenomenon does not apply to all clk worms and does not correlate with lifespan. The disruption of either sod-1 or -2 affects growth and embryonic viability: sod-2 tends to exacerbate the mutant phenotypes, while sod-1 shows both weakly enhancing or weakly suppressing effects. Interestingly, only one mutant, clk-4, and only one phenotype of this mutant, slow post-embryonic development, is suppressed by sod-2 (but not sod-1). Furthermore, disrupting the expression of the sod-1 gene has only moderate or no effect on the lifespan of wild type worms, while sod-2 was shown to extend lifespan. On the whole, our results suggest that low superoxide levels do not participate in extending lifespan and are not the common process inducing the Clk phenotype in these mutants. Yet, several of the mutants analyzed have a dramatically increased lifespan and specifically behave like mutants which affect mitochondrial electron transport such as isp-1. Thus, our findings suggest that electron transport has a crucial role in longevity and developmental rates that is independent of superoxide generation.

C. elegans worms with mutations in the gene CLK-1 develop slowly and have an extended lifespan. CLK-1 encodes a mitochondrial protein that is responsible for the hydroxylation of 5-demethoxyubiquinone (DMQ), the penultimate step of ubiquinone (Coenzyme-Q or UQ) biosynthesis. Structural homologues of CLK-1 are found in mammals, fruit flies, yeast and some types of bacteria. Interestingly, however, there is no structural homologue of CLK-1 in the Arabidopsis genome and no plant homologue can be found in other sequence databases. Yeast with the CLK-1 homologue COQ7 deleted fail to grow on non-fermentable carbon sources. To identify a plant functional homologue of COQ7/CLK-1, an Arabidopsis cDNA expression library was screened for complementation of a yeast coq7 deletion mutant. A clone was identified that rescued the coq7 respiratory deficiency. Although the sequence of the encoded protein has no structural similarity to proteins in the COQ7/CLK-1 family, it contains a monooxygenase/hydroxylase domain that has sequence similarity with the E. coli DMQ hydroxylase encoded by the UBIF gene. Like the structural homologues of COQ7/CLK-1 found in other eukaryotes, the gene (AQX for 'Alternate Quinone monooXygenase') contains a likely mitochondrial targeting presequence at its N-terminus. HPLC analysis of quinone extracts from rescued cog7 strains does not detect ubiquinone, but instead shows another peak that may be DMQ. It is likely that AQX does not hydroxylate yeast DMQ effectively enough to generate detectable levels of UQ. A unique pathway for UQ biosynthesis in plants is proposed that is defined by AQX and Arabidopsis genes identified on the basis of homology to known E. coli and yeast UQ biosynthesis genes.

Thesis (M.S.)--Brigham Young University. Dept. of Biology, 2007. / Includes bibliographical references.

No description available.

No description available.