Thesis (doctoral)--Bern, 1962.

Thesis (doctoral)--Bern, 1962.

Thesis (Ph. D.)--University of Wisconsin--Madison, 1933. / Typescript. Vita. With this is bound: Daturic acid / by Ralph W. Clark. Reprinted from Journal of the American Pharmaceutical Association, vol. XXIV, no. 10 (Oct. 1935), p. [843]-847. Includes bibliographical references.

No description available.

A pathway for the biosynthesis of tropic acid from tryptophan in Datura Stramonium has been proposed by Goodeve, and was supported by Hamon. The purpose of this investigation was to determine quantitatively the percentage of incorporation of tryptophan into tropic acid. This was attempted using vacuum infiltration and sterile root culture techniques with autoradiography being utilized to identify the radioactive metabolites. Tryptophan was not found to be converted to tropic acid under the experimental conditions used in this investigation. The purpose of this investigation was also to extract crude enzyme preparations which would convert certain postulated intermediate compounds into tropic acid. The conversion of a-phenyl-3-aminopropionic acid to atropic acid and the conversion of atropic acid to tropic acid was attempted. The enzyme extracts of Datura Stramonium root tissues were prepared from acetone powders, from fresh tissue, and from freeze-dried tissues. These extracts did not show any activity in vitro. It is concluded that some differences existed between the tissues used in the present investigation and those used in previous work. / Pharmaceutical Sciences, Faculty of / Graduate

There have been two pathways postulated for the biogenesis of tropic acid in Datura stramonium. The first of these, involving the amino acid tryptophan, was proposed by Goodeve and Ramstad¹³. The second utilizes another amino acid, in this case phenylalanine, and was put forward by Leete¹⁵ and independently by Underhill and Youngken Jr.¹⁶. Since there have been these two mechanisms postulated for the biogenesis of tropic acid in this plant, one must conclude that either the two amino acids act via a common pathway or that there are in fact two separate mechanisms for tropic acid biogenesis. The purpose of this investigation was to distinguish between these two possibilities. Tryptophan-3-C¹⁴, tryptophan-(2-indolyl)-C¹⁴, indoleacetic acid-2-C¹⁴, phenylalanine-3-C¹⁴, and uniformly ring labelled phenylalanine-C¹⁴, were fed to separate, one week old, sterile, root tissue cultures of Datura stramonium. The time allowed for the metabolism of the radio-active precursor varied from three to twenty-one days. The tissue was then extracted with ethanol and this extract subjected to two-dimensional paper chromatography. Autoradiography was employed to determine the location of labelled metabolites. These metabolites were then identified by direct comparison to authentic samples chromatographed in an identical fashion. The results of this investigation show that all of the labelled precursors do give rise to labelled tropic acid. The pathway from phenylalanine appears to be the predominate mechanism for tropic acid formation in isolated Datura stramonium root tissue. The pathway from tryptophan, although apparently playing a minor role in tropic acid biosynthesis in this tissue, was shown to be a unique and independent system for the biogenesis of this aromatic acid. It is concluded therefore that there are two separate mechanisms involved in the biogenesis of tropic acid in Datura stramonium root tissue. / Medicine, Faculty of / Anesthesiology, Pharmacology and Therapeutics, Department of / Graduate

Proefschrift - Groningen. / Summary in Dutch and English.

Reproduction de : Thèse d'exercice : MEDECINE : Nancy 1 : 2000. / 2000NAN11031. Titre provenant de l'écran-titre.

Thèse de doctorat : Sciences agronomiques : INPL : 2008. / Titre provenant de l'écran-titre.

Graduation date: 1994