Hydroformylation of 5,6-anhydro-1,2-0-isopropylidene-α-D-glucofuranose (XXIV) with carbon monoxide (70 atm.) and hydrogen (70 atm.) at a temperature of 100-105° C. gave 6-deoxy-1,2-0-i sopropylidene-α-D-gluco-heptodialdo-1,4-furanose-3,7-pyranose (XXV) in 78% yield. Minor quantities of the rearrangement product, 6-deoxy-5-keto-1 ,2-0- i sopropyl i dene-α-D-gl ucofuranose (XXVI), and the hydro-hydroxymethyl at i on product, 6-deoxy-1 ,2-0- isopropyl idene-α-D-gl uco-hepto-1 , 4-furanose (XXVI I), were isolated in 9% and 4% yields, respectively. Acetylation of crude (XXV) afforded two anomeric derivatives (XXIX, XXVII I). Under identical experimental conditions, 5 ,6-dideoxy-1 , 2-0-isopropyl idene-α-D-xylo-hex-5-enofuranose (XXXIII) gave 5,6-dideoxy-α-D-xylo-heptodialdo-1 ,4-furanose-3,7-pyranose (XXXIV) in 51% yield. A minor amount of 5,6-dideoxy-α-D-xy1ohepto-1,4-furanose (XXXV) in about 5% yield was also detected by thin layer chromatography (T.L.C.) Fusion of 5 ,7-di-0-acetyl-6-deoxy-1,2-0-isopropylidene-α-D-gluco-heptodialdo-1,4-furanose-3,7-pyranose (XXVIII) with 5,6-dimethyl-benzimidazole using chloroacetic acid as a catalyst at 170-175°C. gave two anomeric nucleosides 1-(3'-0-acetyl-2'-deoxy-6’,7'-0-isopropylidene heptodialdo-4’,7'-pyrariose-α(and β-)-L-gulopyranosyl) -5,6-dimethyl -benzimidazole (XXXVII, XXXVIII) in 42% yield. These nucleosides were separated by multiple ascending development on preparative T.L.C. plates of silica gel G. impregnated with 2% G.E.Phosphor. Assignment of structures of the nucleosides was based on an analysis of their N.M.R. spectra. / Science, Faculty of / Chemistry, Department of / Graduate

The purpose of this study was to examine the effects of exercise of short duration, and the effects of re-exercise on carbohydrate metabolism. I feel that the levels of severe exercise studied approximate the levels of severe exercise which a rainbow trout probably experiences in its natural environment. The level of blood lactate, blood hemoglobin, muscle lactate, muscle glycogen, and liver glycogen were determined in unanesthetized, intact, one and one-half year old rainbow trout acclimated to 10.5°C. Samples were taken immediately after exercise of 3 seconds to 5 minutes, after recovery of 3 minutes to 60 minutes, and after re-exercise of 3 seconds to 5 minutes. The results indicate that exercise of even the shortest duration studied causes an immediate increase in the level of blood lactate, muscle lactate, and blood hemoglobin. Exercise also causes an immediate decrease in muscle glycogen, but does not cause a change in the level of liver glycogen. Changes during the 60 minute recovery period are slight. In general, the effects of re-exercise after a 60 minute recovery period are additive. A correlation analysis between muscle glycogen and muscle lactate indicates that there is a source of muscle lactate other than muscle glycogen at exercise levels of long duration. The source of this muscle lactate does not appear to come from liver glycogen. The energy may be supplied by catabolism of protein or lipid, or by absorption of foodstuffs from the gut. This study provides evidence that rainbow trout are not well adapted for recovery from severe exercise of short duration. / Medicine, Faculty of / Cellular and Physiological Sciences, Department of / Graduate

A parent and pleomorphic strain of the dermatophyte Microsporum gypseum were cultured in chemically defined media under standardized conditions in order to compare growth kinetics, changes in chemical composition with time, and basic carbohydrate metabolism. In general, the two strains were similar in most respects, although some differences were observed. The growth potential of the pleomorphic form was greater than that of the parent form under most conditions examined. The kinetics of mass increase in liquid culture, and of colonial growth on solid culture were examined and compared to those of other fungi, and to those of bacteria. The equations describing bacterial colonial extension were tested against both strains of M. gypseum, and found to be invalid. The rate of subsurface mass increase was exponential with time. Both strains were found to possess some of the enzymes of the Embden-Meyerhof and hexose-monophosphate glycolytic pathways, the tricarboxylic acid cycle, and isocitrate lyase. No enzymes utilizing glyoxylate were detected, nor were the enzymes exclusive to the Entner-Doudoroff pathway. / Science, Faculty of / Microbiology and Immunology, Department of / Graduate

Behavioral and biochemical correlates of the carbohydrate and tryptophan induced increase in brain serotonin were investigated in a series of 4 experiments. Experiment 1 was conducted to establish the nadir of brain tryptophan during the dark phase of the light cycle, Following a 16 hour fast, brains were removed, at 1600, 1800, 2000, 2.400, and 0400, hrs for tryptophan determination. Analyses indicated no differences in brain tryptophan throughout the dark period. The time course and peak concentrations of the carbohydrate and tryptophan induced increase in brain tryptophan and serotonin were determined in Experiment 2. Rats were fasted from 0030 to 1730 and then offered a control diet and injected with saline or 50 mg/kg tryptophan, or offered a high carbohydrate, protein-free meal and injected with saline. One hour after treatment and hourly for the next 3 hours, brains were obtained for analysis of tryptophan and serotonin. Tryptophan injected rats exhibited a peak in brain tryptophan at 1 hour post injection and a fall in tryptophan to control levels by 2 hours. Carbohydrate fed animals exhibited an increase in brain tryptophan at all times observed. Elevated brain serotonin was found in both tryptophan and carbohydrate treated animals. Experiment 3 was conducted to establish a behavioral correlate of brain serotonin. Behaviors investigated included: latency to step-down and explore a novel chamber and acquisition and extinction of a passive avoidance response. Animals were fed ad libitum, and 1 hour (1700) prior to behavioral testing injected with saline or 50 mg/kg tryptophan. Animals did not differ on measures of passive avoidance acquisition or extinction. However, tryptophan injected animals were found to exhibit a longer latency to step-down and explore a novel chamber than controls. In Experiment 4, plasma corticosterone, latency to step-down, rearing, urination, and defecation in a novel chamber were assessed. Animals were fasted from 2400 to 1700 and injected and fed as in Experiment 2. One and 2 hours following treatment, behaviors were observed. Thereafter, brains were removed for determination of tryptophan and serotonin and blood obtained for plasma corticosterone analysis. In tryptophan administered rats, brain tryptophan was observed to peak at 1 hour post injection and to remain higher than controls at 2 hours post injection. Carbohydrate fed rats were found to exhibit higher levels of brain tryptophan than control animals at both times assayed. Brain serotonin was found to peak in tryptophan treated rats at 1 hour post injection and to remain elevated at 2 hours. No changes in brain serotonin were revealed in carbohydrate fed animals. No group differences were observed for any of the behavioral measures taken. However, increased plasma corticosterone was found in rats fed the high carbohydrate meal. These data revealed that injection of tryptophan resulted in an increased latency to step-down and explore a novel chamber when animals were fed ab libitum, whereas carbohydrate ingestion resulted in an increase in plasma corticosterone with no effect on behavior. Confirmation that serotonin mediated these biochemical and behavioral changes awaits further research. / Land and Food Systems, Faculty of / Graduate

Ph.D. / The intramolecular insertion of allylpalladium species into alkene and alkyne bonds ('metalloene' cyclisation) of acetoxy-2,7-dienes and acetoxy-2-en-7-ynes has evolved into a synthetically powerful process. Proceeding from the favourable results obtained with achiral analogues, the palladium-catalysed 'metallo-ene' reactions of acyclic carbohydrate-derived 1,1-diacetoxy-2,7-diene and 1,1-diacetoxy-2-en-7-yne compounds proceeded in a stereospecific fashion to furnish chiral, multi-functionalised five-membered carbo- and heterocyclic products. A valuable consequence of the reactions of these geminal diacetate starting materials is that the products contain enolacetate, or latent aldehyde moieties. Further elaboration of these functionalities enables the facile entry to an array of substituted five-membered ring compounds, some of which have been identified as synthons or substructures of important natural products. In the presence of carbon monoxide (1 atm) the corresponding cyclic carboxylic acid products were obtained under mild 'metallo-ene' reaction conditions. Cyclised chloro componds were obtained by exposure of the 1,1-diacetoxy-2-en-7-yne substrates to Wacker-like conditions in the presence of an excess of LiC1. The highly atom economical Trost-type cycloisomerisation ensued when these enyne starting materials were stirred in acetic acid in the presence of a palladium(0) catalyst. The mechanism of the palladium-catalysed 'metallo-ene' transformations is discussed with respect to the enantioselectivity of carbopalladation of prochiral alkenes as well as the transition states. The topological influence of pre-existing centres over developing stereogenic centres is evaluated. Following indications that n-allylpalladium complexes can be prepared by the oxidative addition of Pd(0) to an a,13-unsaturated acetal, our next strategy was based on the use of suitably substituted A 2'3-pyranoside rings as chiral templates for the construction of multi-functionalised fivemembered ring systems via Pd-catalysed 'metallo-ene' cyclisations. Enantiomerically pure bi- and/or tricyclic products of carbonyl insertion were obtained in fair to good yields when these 'metallo-ene' reactions were conducted in the presence of CO under mild reaction conditions. Subsequently, bicyclic diene products were prepared via the palladium-catalysed cyclisation of Az3-C-glycoside derivatives. Important revelations concerning the relative stereochemistry of substrates for palladium-catalysed 'metallo-ene' cyclisation/carbonylation of unsaturated C-glycoside derivatives were made. The consecutive introduction of unsaturated C-alkyl side-chains at C-4 and C-1 of selected pseudoglycals via palladium-catalysed nucleophilic allylic substitution reactions accomplished the formation of chiral dienyne compounds. Palladium-catalysed cascade cycloisomerisation of these substrates effected the smooth synthesis of enantiopure tricyclic products. Cascade cyclisation of these highly unsaturated starting materials under Wacker-like conditions afforded [5,6,6]-tricyclic dichloro compounds. A mechanism to account for the stereospecific incorporation of two chlorine atoms into, and the ring expansion of the substrate carbon framework, is proposed. Finally, the readily accessible tert-butyl 6-0-acety1-4-[bis(ethoxycarbonyl)but-3-eny1]-2,3,4- trideoxy-a-D-erythro-hex-2-enopyranoside was converted, via a domino process, into a chiral substituted dihydropyran in the presence of a Pd(II)-catalyst in acetic acid/acetonitrile. By conducting the reaction under an atmosphere of CO, a tetrahydropyran compound containing a carboxylic acid side-chain was obtained, while the corresponding chloro product was prepared when the pseudoglucal starting material was exposed to an excess of LiC1 and CuC1 2 under Wacker-like conditions.

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A research report submitted to the School of Public Health, Faculty of Health Sciences, University of Witwatersrand in partial fulfillment of the requirements for the degree of Master of Public Health. 20 October 2014 / Background: Health experts are calling sugar the new tobacco (Action on Sugar, 2014). The WHO recently revised its recommendations for a maximum daily limit on sugar intake of 25 grams. Yet a 2012 study showed that South African children and adolescents are consuming up to 50 grams and 100 grams per day respectively (Steyn et al., 2003). Sugar is now recognized for its role, not only in promoting caries, obesity and diabetes, but also in the development of cancers. The World Cancer Report 2014, warns of a ‘cancer tidal wave’ over the next 20 years (IARC, 2014) Health promotion alone is insufficient; drawing on the example of tobacco control, such as advertising restrictions, legislation is the key to prevention. The sugar-sweetened beverage (SSB) industry is the leader among all sectors in marketing to young people (Arredondo et al., 2009), thus a similar approach is recommended for restricting SSB advertising to reduce chronic disease risk. There is no data regarding SSB advertising and obesogenic environments in South Africa. This pilot study is the first to describe the location, content and characteristics of outdoor print advertisements for SSBs and fast foods in South Africa. Methodology: This is a secondary analysis of data collected as part of a larger 2013 study investigating the obesogenic environment in Soweto, South Africa. All visible outdoor advertising and branding of SSBs and fast food in a five-square kilometer demarcated area were included. Data on content, quantity, location, size and type of advertisements was collected in the field and a photograph was taken for further analysis. Comparisons were drawn to photographs of alcohol advertising in the same area. Data was captured using a coding sheet and was analysed descriptively and using inferential statistics. The advertisements included billboards, banners, posters, pole advertisements, painted signs, branded school signs, branded shop signs, directional signs and branded umbrellas and fridges. A total of 237 photographs were included in the study. Results: The main findings of this study indicate a significant presence of advertising and branding for sugar-sweetened beverages in Soweto. SSB and fast food advertising and branding accounted for 62.86% of all advertising in the area under study. Of all SSB and fast food brands available in South Africa, Coca-Cola accounted for 86.58% of this advertising and branding. Unlike alcohol advertising, which is restricted to the locations in which alcohol is sold, advertising for SSBs is pervasive throughout the community, seen everywhere from shops and schools to transit stops and on street sides. Most SSB advertising and branding signage is medium or large in size. Images of people were only present in a small number of the adverts. However when people were present, they were consistently young people under the age of 35. The race of people in the adverts consistently represented the black African demographic of Soweto. While the main goal of the adverts appears to be product and brand recognition, there is a trend across the SSB adverts to convey messages of happiness, positivity, friendship, fun and well-being, suggesting that consumption of these products would lend to such outcomes for the consumer. A small percentage also promoted special deals to encourage product purchase. Conclusion: SSB advertising in Soweto is extensive, far surpassing advertising for junk food or alcohol. The government should consider implementing legislation, to restrict SSB advertising. The country should also urgently move to adopt WHO’s new guidelines on the daily upper limit for sugar intake (Mann, 2012), and to limit SSB intake specifically, which should be reflected in revisions to South Africa’s food-based dietary guidelines. Further research should focus on the association between the high rate of exposure to SSB advertising in Soweto and the level of consumption of SSBs and on the understanding of the advertising environment and how this affects the health literacy of South African children and adolescents.

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