No description available.

Thesis--M. Phil., University of Hong Kong, 1986.

published_or_final_version / Physics / Master / Master of Philosophy

Trimethylamine-N-oxide (TMAO) and guanidinium chloride (GdmCl) are both highly studied molecules in the field of protein folding/unfolding. Thermodynamic studies have shown that TMAO, an organic osmolyte, is a strong stabilizer of the protein folded state, while GdmCl is known to be one of the most effective protein denaturants. Although TMAO and GdmCl are well studied the mechanism by which they stabilize and denature proteins, respectively, is not well understood. In fact there are few studies looking at their effects on hydrophobic interactions. In this work we determine the effect of TMAO and GdmCl on hydrophobic interactions, by looking at the model system of phenyl and alkyl hydrophobic contact pairs. Contact pair formation is monitored through the use of fluorescence spectroscopy, i.e., measuring the intrinsic phenol fluorescence being quenched by carboxylate ions. Hydrophobic interactions are isolated from other interactions through a developed methodology. The results show that TMAO addition to the aqueous solvent destabilizes hydrophobic contact-pairs formed between phenol and carboxylate ions. The TMAO acts as a “denaturant” for hydrophobic interactions. For GdmCl the data shows that for small alkyl groups, acetate and propionate, hydrophobic contact-pairs are slightly stabilized or are not affected, respectively. For the larger alkyl groups GdmCl disrupts contact pair formation and destabilizes them. GdmCl’s effect on hydrophobic interactions shows a size dependence on carboxylate ion size, i.e., as carboxylate ion tail length increases the contact pair formed with phenol is destabilized to a greater degree.

No description available.

Thesis (Ph. D.)--University of Adelaide, 1955.

Thesis (Ph. D.)--School of Pharmacy and Dept. of Chemistry. University of Missouri--Kansas City, 2007. / "A dissertation in pharmaceutical sciences and chemistry." Advisor: Ashim K. Mitra. Typescript. Vita. Description based on contents viewed July 16, 2008; title from "catalog record" of the print edition. Includes bibliographical references (leaves 154-179). Online version of the print edition.

Thesis (Ph. D.)--Florida State University, 2004. / Advisor: Dr. Naresh Dalal, Florida State University, College of Arts and Sciences, Dept. of Chemistry and Biochemistry. Title and description from dissertation home page (viewed July 9, 2004). Includes bibliographical references.

Thesis (Ph. D.)--University of Wisconsin--Madison, 1961. / Typescript. Vita. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references.

Le travail porte sur les signaux hormonaux (principalement les cytokinines, CK) influant sur la production d'alcaloïdes indolomonoterpéniques (AIMs) dans des cultures cellulaires de pervenche tropicale, Catharanthus roseus. Des effets synergiques entre les cytokinines et le méthyljasmonate ont été observés à la fois sur l'accumulation des AIMs et sur les gènes codant des enzymes impliquées dans la voie du MEP et des secoiridoïdes (Crdxr et Crg10h). Les effets antagonistes des cytokinines et des gibbérellines (GA) sur la production alcaloïdique ont été mis en évidence. Ces effets ont été également retrouvés sur l'expression de Crdxr et Crg10h. Nous avons également montré que les GAs endogènes inhibent la produciotn des AIMs ainsi, en présence d'inhibiteur de la biosynthèse de GAs, nous avons mis en évidence une simulation significative de la production. Nous avons démontré que la phospholipase D inlue sur la régulation du gène CrRR3 via l'acide phosphatidique. Cependant, l'inhibition de la PLD n'a aucun impact sur l'accumulation des transcrits CrRR1 démontrant une régulation différentielle des régulateurs de réponse de type A. La relation entre la voie de transduction du signal CK et la voie de transduction du signal CK et la voie de biosynthèse des AIMs a été abordée grâce à une stratégie utilisant l'interférence d'ARN inductible aux glucocorticoïdes, la dexaméthasone, ciblant des éléments impliqués dans les étapes précoces de la voie de signalisation cytokinine. Dans les lignées interférées, la simulation des transcrits Crg10h et Crdxr par les cytokinines est totalement abolie. Ces résultats montrent clairement une relation entre la voie de transduction canonique des CKs et la voie de biosynthèse des AIMs. / This thesis deals with the effects of hormonal signaling on the biosynthesis of monoterpenoid indole alkaloids (MIAs) in Catharanthus roseus cell suspension cultures, with special emphasis on cytokinin (CK) signaling. Synergistic effects between CK and methyljasmonate have been documented both on MIAs accumulation and on transcript level of genes encoding enzymes of the MEP and seccoiridoïd pathways (Crdxr andCrg10h). CK and gibberellin (GA) exerted antagonistic effects on alkaloid accumulation in a dose-dependant manner and at low concentrations. These effects were also observed on Crdxr and Crg10h gene transcript levels with low doses of GA. We have also shown that endogenous gibbellins inhibit MIAs accumulation. Thus, in presence of GA biosynthesis inhibitor, paclobutrazol, the accumulation of MIAs is dramatically increased. We have established that phospholipase D (PLD) regulates the espression of CrRR3, encoding a type A response regulator, via its product, phosphatidic acid. On the other hand, PLD had no effects on CrRR1, suggestiong that response tegulators may be differentially regulated by CK in periwinkle cells. Studies on the relationship between CK signal transduction and MIAs biosynthesis pathway have been developped using a dexamethasone (DEX) inducible RNAi system targeting elements of the early steps of CK signaling. In transgenic cell lines, in presence of DEX, the up-regulation of Crdxr and Crg10h genes by CK was completely abolished. Theses results clearly show a relationship between the canonical CK signaling and the MIAs biosynthetic pathway.