In Part I, a modified synthesis of radio-labelled secodine (68) and its incorporation into vindoline (7) is described. In a model study, for the synthesis of side-chain labelled 3-ethylpyridine (74), [2-² H]-(3'-pyridyl)-ethane was achieved from the correspondingly labelled 3-acetylpyridine by desulphurization of the intermediate thioketal (93). In a second study, [1- ³H]-(3'-pyridyl)- ethane was synthesized by treating 3-acetylpyridine with sodium borohydride-³H. The resulting alcohol (95) was acetylated, and hydrogenolysis achieved the desired product. The ester alcohol (74) was coupled to [1- ³H]-(3'-pyridyl)-ethane and the resulting pyridinum salt (90) was reduced to the corresponding piperdeine ester (80) in a "one-pot" synthesis. The conversion of (80) to [19-³H]-secodine was achieved by a known procedure. In two experiments, [19-³H, ¹⁴C0₂CH₃]-secodine (68)(³H/¹³C ratios = 3.00 and 1.54) was administered to Catharanthus roseus plants. The vindoline (7) which was isolated was shown to have been biosynthesized from the entire secodine molecule (³H/¹³C = 3.31 and 1.35 respectively). In Part II, a degradation scheme designed to achieve the isolation of the N-methyl group of uleine (1) is described as well as preliminary results from an investigation into the biosynthesis of uleine (1) and olivacine (4). Variously radio-labelled forms of tryptophan (15), anthranilic acid and secodine (18) were administered to Aspidosperma pyricollum root segments and whole plants. The uleine (1) which was isolated was found to be inactive in all experiments. Variously radio-labelled forms of tryptophan (15), anthranilic acid and secodine (18) as well as ¹⁴CH₃-methionine (30) was administered to Aspidosperma australe plants. Uleine (1) and olivacine (4) was isolated. The only incorporation that could be demonstrated was that of ¹⁴CH₃ methionine (30) into uleine (1) to the extent of 0.168% and 0.147%. The isolation of the N-methyl group from (1) showed that it contained 97% and 98% of the activity. In Part III, the attempted synthesis of compounds of the preakuammicine- and stemmadenine-series is described. A new method for the C-18 deoxygenation of curan derivatives using Birch reduction conditions was achieved. Also, a modification of the Oppenauer oxidation of the curenol (36) to achieve improved yields of the aldehyde (37) and nor-fluorocurarine (39) was developed. The introduction of a carbomethoxy group into the C-16 position of the curan aldehyde derivatives (44) and (50) using a base and methylchloroformate was unsuccessful. Also, the introduction of cyanide into position C-16 of the indole alcohol (52) or indole acetate (57) via the corresponding chloroindolenines was unsuccessful. The synthesis of product (60), which is believed to be identical with preakuammicine aldehyde (7), was achieved. This material could not be converted into akuammicine (5) or stemmadenine (4). Only the dehydrated indolenine (72) could be obtained. The ring-opening reaction of the corresponding thioacetal derivative (73) yielded the decarboxylated indole thioacetals (75) and (76). / Science, Faculty of / Chemistry, Department of / Graduate

No description available.

Wong Chi-Fai. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2002. / Includes bibliographical references (leaves 119-132). / Abstracts in English and Chinese. / Abstract --- p.i / Acknowledgements --- p.iv / List of Abbreviations --- p.v / List of Figures --- p.vii / List of Tables --- p.ix / Chapter 1 --- Introduction / Chapter 1.1 --- Plant secondary metabolites --- p.1 / Chapter 1.2 --- Plant alkaloids --- p.6 / Chapter 1.3 --- Narciclasine --- p.12 / Chapter 1.3.1 --- Isoquinoline alkaloids --- p.12 / Chapter 1.3.2 --- Amaryllidaceae alkaloids --- p.14 / Chapter 1.3.3 --- Narcissus --- p.16 / Chapter 1.3.4 --- Narciclasine --- p.17 / Chapter 1.3.4.1 --- Isolation --- p.17 / Chapter 1.3.4.2 --- Biological and pharmaceutical functions --- p.20 / Chapter 1.3.5 --- High performance liquid chromatography (HPLC) --- p.23 / Chapter 1.3.6 --- In vitro protein synthesis --- p.24 / Chapter 1.3.6.1 --- Rabbit reticulocyte lysate --- p.25 / Chapter 1.3.6.2 --- Wheat germ extract --- p.25 / Chapter 1.3.6.3 --- Non-radioactive colorimetric detection system --- p.26 / Chapter 1.4 --- Objective --- p.28 / Chapter 2 --- Materials and Methods / Chapter 2.1 --- Plant materials --- p.29 / Chapter 2.2 --- Extraction of narcicalsine --- p.29 / Chapter 2.3 --- Distribution of NCS in Narcissus tazetta --- p.30 / Chapter 2.4 --- Stability test --- p.31 / Chapter 2.4.1 --- HPLC analysis --- p.31 / Chapter 2.4.1.1 --- HPLC system --- p.31 / Chapter 2.4.1.2 --- Analytical condition --- p.31 / Chapter 2.4.2 --- Seed germination assay --- p.32 / Chapter 2.5 --- Mode of action of NCS --- p.33 / Chapter 2.5.1 --- In vitro translation --- p.33 / Chapter 2.5.1.1 --- In vitro translation --- p.33 / Chapter 2.5.1.2 --- SDS-PAGE analysis --- p.33 / Chapter 2.5.1.3 --- Western blot analysis --- p.34 / Chapter 2.5.1.4 --- Colorimetric detection --- p.34 / Chapter 2.5.2 --- Assay of induction of a-amylase synthesis in aleurone cells of barley grains by GA3 --- p.36 / Chapter 2.5.2.1 --- Chemicals and reagents --- p.36 / Chapter 2.5.2.2 --- Reducing sugar assay --- p.37 / Chapter 2.5.3 --- Root tip smear --- p.43 / Chapter 2.5.3.1 --- Chemicals and reagents --- p.43 / Chapter 2.5.3.2 --- Assay --- p.43 / Chapter 2.6 --- Allelopathic test --- p.45 / Chapter 2.6.1 --- Soil planting --- p.45 / Chapter 2.6.1.1 --- Foliage spray --- p.45 / Chapter 2.6.1.2 --- Planting with Narcissus bulb --- p.45 / Chapter 2.6.2 --- Hydroponics --- p.46 / Chapter 2.7 --- Effect of NCS on plant cells via tissue culture --- p.48 / Chapter 2.7.1 --- Establishment of tissue culture system --- p.48 / Chapter 2.7.1.1 --- Initiation and maintenance of carrot callus --- p.48 / Chapter 2.7.1.2 --- Initiation and maintenance of tobacco callus --- p.49 / Chapter 2.7.1.3 --- Initiation and maintenance of Narcissus callus --- p.50 / Chapter 2.7.1.4 --- Optimisation of callus growth --- p.50 / Chapter 2.7.2 --- Effects of NCS --- p.51 / Chapter 2.7.3 --- Effect of tobacco extract on NCS --- p.51 / Chapter 2.7.3.1 --- Extraction of tobacco extract --- p.51 / Chapter 2.7.3.2 --- Bioassay --- p.52 / Chapter 2.8 --- Assay of effect of NCS on microorganisms --- p.53 / Chapter 2.8.1 --- Antibacterial activity --- p.53 / Chapter 2.8.1.1 --- Total bacterial count --- p.53 / Chapter A. --- Chemicals and reagents --- p.53 / Chapter B. --- Serial dilution --- p.54 / Chapter C. --- Assay --- p.54 / Chapter 2.8.1.2 --- Turbidity test --- p.55 / Chapter A. --- Bacteria --- p.55 / Chapter B. --- Chemicals and reagents --- p.55 / Chapter C. --- Assay --- p.55 / Chapter 2.8.2 --- Anti-fungal and anti-yeast activity --- p.56 / Chapter 2.8.2.1 --- Disc diffusion method --- p.56 / Chapter A. --- Fungi --- p.56 / Chapter B. --- Chemicals and reagents --- p.56 / Chapter C. --- Assay --- p.56 / Chapter 2.8.2.2 --- Tube dilution method --- p.57 / Chapter A. --- Yeast --- p.57 / Chapter B. --- Chemicals and reagents --- p.57 / Chapter C. --- Assay --- p.57 / Chapter 2.9 --- Statistical analysis / Chapter 3 --- Results / Chapter 3.1 --- Distribution of NCS in Narcissus tazetta --- p.59 / Chapter 3.2 --- Stability of NCS --- p.62 / Chapter 3.2.1 --- HPLC analysis --- p.62 / Chapter 3.2.2 --- Bioassay --- p.62 / Chapter 3.3 --- Mode of action of NCS --- p.66 / Chapter 3.3.1 --- In vitro translation --- p.66 / Chapter 3.3.2 --- Effect ofNCS on the induction of a-amylase synthesis in aleurone cells of barley grains by GA3 --- p.69 / Chapter 3.3.3 --- Root tip smear --- p.74 / Chapter 3.4 --- Allelopathic test --- p.77 / Chapter 3.4.1 --- Soil planting --- p.77 / Chapter 3.4.1.1 --- Foliage applications --- p.77 / Chapter 3.4.1.2 --- Planting with Narcissus bulb --- p.77 / Chapter 3.4.2 --- Hydroponics --- p.78 / Chapter 3.5 --- Effect of NCS on plant cells via tissue culture --- p.91 / Chapter 3.5.1 --- Optimisation of Narcissus callus growth --- p.91 / Chapter 3.5.2 --- "Effects of NCS on Narcissus, carrot and tobacco calli" --- p.91 / Chapter 3.5.3 --- Effect of tobacco extract on NCS --- p.91 / Chapter 3.6 --- Effect of NCS on microorganisms --- p.95 / Chapter 3.6.1 --- Antibacterial activity --- p.95 / Chapter 3.6.1.1 --- Total bacterial count --- p.95 / Chapter 3.6.1.2 --- Turbidity test --- p.95 / Chapter 3.6.2 --- Anti-fungal and anti-yeast activities --- p.95 / Chapter 3.6.2.1 --- Disc diffusion method --- p.95 / Chapter 3.6.2.2 --- Tube dilution method --- p.96 / Chapter 4 --- Discussion / Chapter 4.1 --- General properties --- p.103 / Chapter 4.2 --- Mode of action --- p.105 / Chapter 4.3 --- Other biological properties --- p.108 / Chapter 4.3.1 --- Allelopathic property --- p.108 / Chapter 4.3.2 --- Effect on other plants via tissue culture --- p.110 / Chapter 4.3.3 --- Effect on microoraganisms --- p.112 / Chapter 4.4 --- Further studies --- p.114 / Chapter 5 --- Conclusion --- p.115 / Appendix --- p.116 / References --- p.119

Vestibular system (VN) is involved in the spatial recognition of animals. Animals with impaired VN were observed with poor spatial navigation abilities. The purpose of this thesis is to study the effect of muscimol on the spatial recognition of rats. It was found that the neonatal diffusion of muscimol to the VN significantly affected the spatial recognition of rats during dead reckoning test. In the light probe test, which distal visual cues were available, the treated rats spent significantly less time searching for the food pellet (student’s t-test: p<0.001). The return time was significantly higher in treated group than the sham control groupwhen they were tested in in the dark probe test (student’s t-test: p<0.001), which animals were limited to idiothetic cues. Similarly, the heading angles were significantly higher in all three different conditions, light/dark probe and new location tests (light: p<0.001; dark: p<0.001; new location: p<0.01). This finding suggests that neonatal diffusion of muscimol affects the development of vestibular nuclei and that thevestibular system is important for the processing of vestibular informationin spatial recognition. / published_or_final_version / Physiology / Master / Master of Medical Sciences

published_or_final_version / Biochemistry / Master / Master of Science

published_or_final_version / Biochemistry / Doctoral / Doctor of Philosophy

No description available.

The levels of the psychoactive alkaloids S-(-)-cathinone and its primary metabolite cathine, consisting of the diastereomers (+) -norpseudoephedrine and (-)- norephedrine were determined in Catha edulis (Vahl) Forssk. ex Endl., Catha transvaalensis Codd and Catha abbottii Van Wyk & Prins. Alkaloid levels were investigated in C. edulis plants collected from three different localities in South Africa, and one from a Nairobi khat market. The efficiency of three different methods for the extraction and isolation of cathinone and cathine were investigated, viz. an aqueous acid extraction, an organic solvent extraction and an aqueous acid extraction using the commercially available Extrelutᴿ procedure. The aqueous acid extraction resulted in the rapid loss of cathinone and yielded variable alkaloid levels in replicate studies. This was also observed when this method was coupled with the Extrelutᴿ procedure. In contrast, the organic solvent extraction did not result in a loss of cathinone and provided consistent results over a number of replicates; it also proved to be a simple and rapid method for extracting and isolating cathinone and cathine. A trifluoroacetic acid (TFA) derivatization procedure which has been suggested to produce characteristic diagnostic fragments for gas chromatography / mass spectrometry (GC/MS) identification, was investigated, but failed to produce consistent TFA derivatives of cathinone and cathine. However, underivatized cathinone and cathine were easily identified by GCMS due to their unambiguous mass spectra. All subsequent studies were undertaken using the organic solvent extraction and isolation method, coupled with GC analysis and GC/MS identification of underivatized cathinone and cathine. Leaves of C. edulis were found to contain cathinone and cathine at levels 100 times higher than those of C. transvaalensis. The alkaloids were undetectable in C. abbottii. Plants grown from cuttings of C. edulis collected from the Durban Botanical Gardens were found to contain cathinone and cathine at levels of 0.410 mg per gram fresh weight and 0.157 mg per gram fresh weight in leaves, respectively, while these levels in plants derived from different localities decreased in the order: Eastern Cape (0.319 mg/g f.w cathinone and 0.029 mg/g f.w cathine), Mpumalanga (0.139 mg/g f.w. cathinone and 0.171 mg/g f.w. cathine) and Nairobi (0.032 mg/g f.w. cathinone and 0.025 mg/g f. w. cathine). In an investigation of the cathinone levels in the different plant parts it was found that the highest levels were found in leaves of the shoot tip (0.243 mg/g f.w.) but decreased with the age of the leaf and developmental stage of the plant in the order: juvenile leaves (0.124 mg/g f.w.), mature leaves (0.035 mg/g f.w.), young stem (0.033 mg/g f.w.) and mature stem (0.004 mg/g f.w.). Concomitantly, cathine levels increased with the age of the leaf: leaves of the shoot tip (0.006 mg/g f.w.), juvenile leaves (0.011 mg/g f.w.), mature leaves (0.019 mg/g f.w.). The cathine level in the young stem material was found to be the highest in the entire plant (0.270 mg/g f.w.) but decreased markedly in the mature stem (0.052 mg/g f.w.). Both cathinone and cathine levels in the mature root were greater than levels in the mature stern, being 0.012 mg cathinone per gram fresh weight, and 0.063 mg cathine per gram fresh weight. Neither cathinone nor cathine were detectable in young root material. / Thesis (M.Sc.)-University of Natal, Pietermaritzburg, 2001.

Lupin seed has the potential to be used as a protein supplement in ruminant rations, but its usage is restricted by the presence of alkaloids. Experiments were conducted with the aim of determining whether the removal of specific toxic alkaloids, lupanine and 13-hydroxylupanine, from crushed lupin seed (CLS) would improve the organic matter intake (OMI) and average daily gains (ADG) in lambs, and also improve the lactation performance in dairy cows. Effects on liver function in lambs were also investigated. An additional study on the effects of the detoxification of CLS on the degradation of protein was conducted. In Experiment 1, 30 growing Corriedale lambs were fed five diets for 105 d according to a randomized complete block design (RCBD) with six blocks. Two diets contained intact CLS at 15% (LUI-15) or 30% (LUI-30) of DM; two other diets contained detoxified CLS at 15% (LUD-15) or 30% (LUD-30) and the control (CON) diet was supplemented with crushed sunflower seed, which was locally prepared, on-farm. All diets were formulated to be isonitrogenous (16% CP). The alkaloid content (lupanine and 13-OH lupanine) of the diets was.31,.70,.21 and.52% for LUI-15, LUI-30, LUD-15 and LUD-30, respectively. Thus, diets containing detoxified CLS contained approximately 30% less alkaloids than those with intact CLS. Estimates of ADG of lambs fed diets containing detoxified CLS was higher (P $<$.01) (120 g.d$ sp{-1}$) than that of lambs fed intact CLS (76 g.d$ sp{-1}$). The OMI (73 g/Wkg$ sp{0.75}$) was also higher, although not significantly, for lambs fed diets containing detoxified CLS. Feed conversion efficiency was increased (P $<$.05) by the detoxification of CLS. Lambs fed diets containing intact CLS consumed more OMI as time progressed, suggesting that adaptation to CLS might have occurred. Lambs fed diets containing intact CLS demonstrated increased trends in the activity in plasma of the enzymes glutamic oxaloacetic transferase (GOT) and $ gamma$-glutamyl transfer

The survival and physiology of rainbow trout in alkaline waters was the focus of this thesis. It is known that salmonids have problems with ammonia excretion in alkaline water (Cameron and Heisler, 1983; Wright and Wood, 1985). The first set of studies attempted to increase the survival rates of rainbow trout planted into alkaline lakes by acclimating them to the alkaline conditions before their release. The first field study acclimated rainbow trout to alkaline waters by acidifying the lake water with C0₂ in order to reduce the magnitude of the pH change experienced by the fish. The second field study acclimated rainbow trout to alkaline waters by increasing the alkalinity of the hatchery water in which the fish were held, over a six day period. In both studies the acclimated fish experienced higher survival rates relative to non-acclimated fish. Plasma sodium concentrations ([Na⁺]p1) of the fish were shown to increase, while plasma chloride concentrations decreased. These changes were attributed to an increase in the exchange of external Na⁺ with endogenous H⁺, and the decrease in the exchange of endogenous HC0₃⁻ with external Cl⁻, respectively. The increased [Na⁺]pl may have also been the result of the exchange of plasma ammonium (NH₄⁺) with external Na⁺. The second set of studies investigated the physiological response of rainbow trout to alkaline waters. The first study, the chronic exposure of rainbow trout to alkaline water, showed that trout in hard alkaline water experienced higher survival rates and regulated plasma ammonia and ion concentrations more competently than trout in soft alkaline water. This increased ability to regulate plasma ammonia and ion concentrations was attributed to the possible "reactivation" of the Na⁺/NH₄⁺ exchange. The purpose of the second study, the acute exposure of rainbow trout to alkaline water, was to further investigate the mechanisms that enable fish in hard alkaline water to survive better than fish in soft alkaline water. The possible activity of the Na⁺/NH₄⁺ exchange was again observed in the hard alkaline water. The addition of amiloride to the alkaline hard treatment water increased plasma total ammonia and stabilized [Na⁺]pl′, which supported the "reactivation" of the Na⁺/NH₄⁺ exchange in hard alkaline water. As a result of these studies, the acclimation of rainbow trout to hard alkaline water before being planted into any alkaline body of water was recommended. / Land and Food Systems, Faculty of / Graduate