Marine organisms have attracted much attention as potential source for drugs over recent years. Soft corals have yielded many bioactive metabolites. Some of them have been examined for their pharmacological properties. For the process of drug discovery, we have examined bioactive metabolites from the organic extracts of two soft corals Sinularia gibberosa and Sarcophyton sp. collected off Formosan coast. This study had led to the isolation of forty-two natural products (1¡V42), including one new £]-caryophyllene-type sesquiterpenoid (1), four new xeniaphyllane-type norditerpenoids (2, 14, 16, and 17), fourteen new xeniaphyllane-type diterpenoids (3¡V13 and 18¡V20), one novel nor-humulene (15), seven new xeniaphyllane-type diterpenoids (21¡V26) with cyclic peroxyhemiketal (3,6-dihydro-1,2-dioxin-3-ol) moiety, and one new steroid (27), along with five known compounds (28¡V32) from Sinularia gibberosa. Three new cembrane-type diterpenoids (33¡V35), along with seven known cembranolides (36¡V42) were isolated from Sarcophyton sp. The structures of metabolites 1¡V42 including their stereochemistry have been established by detailed spectroscopic analyses, particularly mass, 2D NMR (1H¡V1H COSY, HMQC, HMBC, and NOESY) spectroscopy and by comparison with the related physical and spectral data from other known compounds. In above metabolites, two compounds (8, 9) exhibited cytotoxicity against the growth of MCF-7, Hep 3B, Ca9-22 cancer cell lines. Furthermore, nine compounds (4, 8, 9, 11, 12, 13, 21, 31, 39) exhibited cytotoxicity against the growth of MDA-MB-231, Hep G2 and A-549 cancer cell lines.

Jadomycins are secondary metabolites produced by Streptomyces venezuelae ISP5230 VS1099 in response to conditions of stress such as heat or ethanol shock. They have been shown to exhibit antibiotic and anticancer activity. Unique structural features of the jadomycins include a rare 2,6-dideoxysugar, L-digitoxose, and an oxazolone ring with an amino acid component. Previous studies have revealed that jadomycin derivatives can be produced by altering the amino acid in S. venezuelae ISP5230 VS1099 culture media which becomes incorporated into the oxazolone ring. One jadomycin from a proteogenic amino acid and three new jadomycins from non-proteogenic amino acids have been successfully produced on a large scale (4 mg/L to 12 mg/L, 2 L) and characterized using mass spectrometry, infrared spectroscopy, UV-visible spectroscopy, and nuclear magnetic resonance spectroscopy. One of these contains a terminal alkyne functionality and has been used in cycloaddition reactions with various azides to produce a library of triazole-containing jadomycins.

Temperate maize is one of few model species that relies mainly on endogenous indicators of the plant’s developmental stage to cue the onset of reproductive development. The INDETERMINATE1 (ID1) transcription factor is a key regulator of the floral transition and id1 mutants are very late-flowering. ID1 is expressed and remains localized in developing leaves, while florigenic signals originate in mature, photosynthetically active leaves. Since very little is known about the molecular components of the floral transition in maize, and in autonomously flowering species at large, this work utilized id1 mutants to analyze the transcriptional and physiological alterations associated with the floral transition in maize. Analyses of functional categories of transcriptional change between developing leaves of id1 non-flowering mutants and normal flowering maize suggest a role for ID1 in energy metabolism and epigenetic regulation of leaf development. In addition, a novel family of -glucosidase genes were found to be expressed exclusively in immature leaves of normal flowering maize in a pattern similar to the ID1 gene suggesting that these genes may act in concert downstream of ID1. Further, profiling of transcript and metabolite alterations in mature leaves, which are likely the source of floral cues, suggest that coordination of resource storage in the form of transitory starch is an important signal for floral promotion in maize. Finally, analysis of the floral transition in Balsas teosinte, the progenitor of modern maize and an obligate short-day plant, suggests that ID1 may define a regulatory module unique to the autonomous floral regulation pathway in maize and related grass species.

Thesis (MSc)--Stellenbosch University, 2013. / ENGLISH ABSTRACT: See item for full abstract / AFRIKAANS OPSOMMING: Sien item vir volteks / IPB, National Research Foundation (NRF) and SASRI for funding

Le succès évolutif des Cnidaires symbiotiques réside en grande partie dans leurs échanges trophiques établis avec les Dinoflagellés du genre Symbiodinium. Cependant, le réchauffement climatique global ainsi que les pollutions ont un impact fort sur les écosystèmes coralliens, notamment en conduisant à la rupture de la symbiose, phénomène appelé blanchissement. La compréhension des mécanismes qui régissent l’établissement, le maintien et la rupture de la symbiose est essentielle à la prévention des épisodes de blanchissement massif. Dans ce contexte, les objectifs de mon projet de thèse sont de caractériser les médiateurs chimiques de l’anémone de mer Anemonia viridis, de les localiser, et d’analyser leur réponse face à un stress. Parmi les composés caractérisés, les lipides et les bétaïnes sont les plus abondants et présentent une grande diversité. Certains sont transférés des symbiotes vers l’hôte. Des anémones de mer ont ensuite été traitées en laboratoire afin de provoquer la rupture de la symbiose et le blanchissement des individus. Une étude cinétique a été menée par une approche globale comparative identique à celle réalisée sur l’anémone symbiotique. Par ailleurs, une cartographie de l’évolution de composés clé a été réalisée par MALDI-MSI. La réponse au stress a été évaluée et a permis d’identifier des lipides de bétaïne et trois indicateurs lipidiques comme marqueurs de réponse précoce au stress. L’ensemble de ces résultats apporte de nouveaux éléments de réponse concernant le rôle des médiateurs chimiques clés dans le maintien de la symbiose, ainsi que leur influence sur sa rupture. / The ecological success of cnidarian-dinoflagellate symbiosis mainly relies on nutrient recycling. Environmental changes, such as global warming or pollution, often result to symbiosis breakdown, also called cnidarian bleaching. The understanding of mechanisms regulating the symbiosis establishment, maintenance and breakdown is essential to prevent massive bleaching phenomena. In this respect, my PhD project focused on the characterization of chemical mediators expressed in the sea anemone Anemonia viridis, their localization and their modulation by stress conditions. A comparative study was first conducted to characterize the chemical mediators and analyze their distribution within the symbiotic sea anemone. We described a great abundance and diversity of lipids in A. viridis tissues. From these results, we proposed possible transfers of FAs between the symbiotic partners. A thermal stress and a chemical stress have also been applied in laboratory-controlled conditions in order to induce symbiosis breakdown and bleaching of the sea anemones, in order to correlate A. viridis metabolome to its symbiotic status. A mapping of these metabolites has been performed by MALDI-MSI of tentacle cross-sections, as well as their evolution following stress. Some betaine lipids have thus been proposed as short-term indicators of stress. A. viridis stress response has also been evaluated with a lipidomic approach, and allowed to identify 3 lipid indicators of early stress response based on membrane fluidity markers. Overall, this study provides insight on key chemical mediators that may regulate the symbiosis maintenance, and may contribute to the symbiosis breakdown.

A seleção de animais para consumo alimentar residual (RFI) está intrinsecamente associada com a diminuição do consumo matéria seca e é independente do ganho de peso corporal, selecionando animais de eficiência produtiva e econômica, além também de diminuir a emissão de gases de efeito estufa provinda do gado. Neste estudo, amostras de soro de 16 animais selecionados divergentemente para eficiência de alimentação foram coletadas antes do confinamento (dia -21) e avaliadas em uma abordagem metabolômica global, com o objetivo de usar análise diferencial, análise de co-expressão e enriquecimento funcional, identificando marcadores para eficiência de alimentação antes do confinamento. Um analito foi diferencialmente presente entre os animais de baixo e alto RFI. A análise WGCNA identificou 22 e 25 módulos no modo positivo e negativo, respectivamente e, 1 módulo de cada modo foi fortemente associado a RFI (r = 0,53, p-valor <0,05 e r = 0,52, p-valor <0,1 nos modos negativo e positivo, respectivamente). A análise de enriquecimento funcional predize 13 processos biológicos associados à eficiência alimentar, incluindo alterações no metabolismo de vitaminas lipossolúveis, inflamação, estresse oxidativo, metabolismo de aminoácidos e metabolismo de ácidos graxos. Esse trabalho evidencia a possibilidade de se identificar um biomarcador para eficiência alimentar e também sugerem que as diferenças nas respostas ao estresse oxidativo e nos processos inflamatórios já influenciam na variação da eficiência alimentar previamente ao confinamento. / Animal selection for residual feed intake (RFI) is intrinsically associated with decreased consumption of dry matter independent of body weight gain, selecting yielding increased production and economic efficiency but also decreasing the greenhouse gas emission of livestock. In this study, serum samples of 16 animals selected for divergent feed efficiency were collected prior to feedlot (day -21) and evaluated in an untargeted metabolomics approach, with the goal of using differential analysis, co-expression analysis and functional enrichment to identifier markers for feed efficiency prior to the feedlot. One feature was differentially accumulated between low and high RFI. WGCNA analysis identified 22 and 25 modules in positive and negative mode, respectively, of 1 module of each mode was strongly associated with RFI (r= 0.53, p-value <0.05 and r=0.52, p-value < 0.1 to negative and positive mode, respectively). Pathway enrichment analysis yielded 13 biological processes associated with feed efficiency including alterations in vitamins liposoluble metabolism, inflammation, oxidative stress, amino acid metabolism and fatty acid metabolism. Our findings suggest the possibility to identify a biomarker for feed efficiency and also discuss that differences in oxidative stress responses and inflammatory processes could explain the feed efficiency variation prior to feedlot.

Carbon dioxide serves as co-substrate in the production of succinic acid by Actinobacillus succinogenes. The transient concentration of dissolved CO2 in the broth (CCO2) controls the uptake of CO2 in the cell. Based on CCO2 , three distinct regimes could be identified in which the behaviour of the organism differed with CCO2 availability. When CCO2 was higher than 8.4 mM (44.4% saturated at an atmospheric pressure of 86 kPa), there was no evidence of CO2 limiting succinic acid productivity and flux to succinic acid remained constant. When CCO2 decreased below 8.4 mM a decrease in the succinic acid production and glucose consumption rates was observed to 28.01% and 19.89% of their original value respectively, at the lowest CCO2 value investigated. Below a CCO2 of 4 mM (21.16% saturated at an atmospheric pressure of 86 kPa), the productivity continued to decrease along with a shift in the total carbon flux from the succinic acid-producing pathway (C4-pathway) to the by-product-producing pathway (C3-pathway). The fraction of total carbon flux directed to the C4-pathway decreased from 0.48 to 0.33 at the lowest CCO2 value investigated. Although the by-product acetic acid concentration decreased to 88% of the original value, formic acid remained relatively stable and the ethanol concentration increased from an average of 0.26 g.L-1 to 1 g.L-1. The organism starts producing ethanol in order to satisfy the redox balance when the C4-pathway becomes less active. It was calculated that the flux shift to the C3-pathway does not favour ATP production. The organism is, however, still viable at the very low ATP production rates found at very low values of CCO2. Since succinic acid production is not limited at relatively low values of CCO2 (44.4% saturation), adequate CO2 supply to the fermenter can be achieved without major CO2 sparging which is beneficial from an industrial processing perspective. / Dissertation (MEng)--University of Pretoria, 2016. / Chemical Engineering / MEng / Unrestricted

The effects of supplementation of the leucine metabolite β-hydroxy-β- methylbutyrate (HMB) were examined in a resistance training study. Thirty- nine men and 36 women between the ages of 20-40 y were randomized to either a placebo (P) supplemented or HMB supplemented (3.0 g HMB/d) group in two gender cohorts. All subjects trained three times per week for 4 wk. In the HMB group, plasma creatine phosphokinase levels tended to be suppressed compared to the placebo group following the 4 wk of resistance training (HMB:174.4 ± 26.8 to 173.5 ± 17.0 U/L; P:155.0 ± 20.8 to 195.2 ± 23.5 U/L). There were no significant differences in strength gains based on prior training status or gender with HMB supplementation. The HMB group had a greater increase in upper body strength than the placebo group (HMB:7.5 ± 0.6 kg; P:5.2 ± 0.6 kg; P = 0.008). The HMB groups increased fat-free weight by 1.4 ± 0.2 kg and decreased percent fat by 1.1% ± 0.2% while the placebo groups increased fat-free weight by 0.9 ± 0.2 kg and decreased percent fat by 0.5% ± 0.2% (fat-free weight P = 0.08, percent fat P = 0.08, HMB compared to placebo). In summary, this is the first short-term study to investigate the roles of gender and training status on the effects of HMB supplementation on strength and body composition. This study showed, regardless of gender or training status, HMB may increase upper body strength and minimize muscle damage when combined with an exercise program.

Arthrobacter belongs to an underexplored genus of antimicrobial-producing bacteria. All species in this genus are Gram-positive and commonly isolated from soil and marine sources. This genus is known to exhibit metabolic versatility greatly influenced by environmental conditions and nutrition. Arthrobacter sp. strain TAJX1902 isolated from an unknown soil sample is shown to inhibit a filamentous indicator type bacterium. It produced a few bioactive secondary metabolites in rich medium (RM) broth and agar culture. TAJX1902 crude extract was primarily fractionated using a Sephedex LH-20 column. Further purification achieved via Flash Column Chromatography and Preparative Thin layer Chromatography yielded five prominent crude products. The scope of this project is to fully determine the structure of potential novel antibacterial compounds from TAJX1902 via spectroscopic techniques including full 2D-NMR spectroscopic data set in combination with High-Resolution Mass Spectroscopy (HRMS). The research work is currently underway towards the final purification of the compounds using High-Performance Liquid Chromatography (HPLC) method to enable structural determination and evaluation of their antimicrobial activities.

Polycyclic aromatic hydrocarbons (PAH) are important environmental pollutants generally formed during incomplete combustion of organic matter containing carbon and hydrogen. Introduced into the human body by adsorption through the skin, ingestion or inhalation, the biotransformation processes of PAH lead to the formation of multiple metabolites. Due to the short elimination lifetime from the body, the quantitative determination of monohydroxy-PAH (OH-PAH) in urine samples provides accurate information on recent exposure to environmental PAH. Urine analysis of OH-PAH with established methodology relies on sample clean-up and pre-concentration followed by chromatographic separation and quantification. Although chromatographic techniques provide reliable results in the analysis of OH-PAH, their experimental procedures are time consuming and expensive. Additional problems arise when laboratory procedures are scaled up to handle thousands of samples under mass screening conditions. Under the prospective of a sustainable environment, the large usage of organic solvents is one of the main limitations of current chromatographic methodology. It is within this context that new analytical approaches based on easy-to-use and cost-effective methodology become extremely relevant. This dissertation focuses on the development of screening methodology for the routine analysis of PAH metabolites in numerous samples. It explores the room-temperature fluorescence properties of six metabolites originating from parent PAH included in the Environmental Protection Agency priority pollutants list. 1- hydroxyfluorene, 1-hydroxypyrene, 6-hydroxychrysene, 9-hydroxyphenanthrene, 3- hydroxybenzo[a]pyrene and 4-hydroxybenzo[a]pyrene are used as model biomarkers to investigate the analytical potential of new methods based on solid-phase extraction (SPE) and iii room-temperature fluorescence (RTF) spectroscopy. Quantitative determination of metabolites is carried out either in the eluent extract[1, 2] or on the surface of extraction membranes[3, 4] . The direct determination – i.e., no chromatographic separation - of the six metabolites is based on the collection of excitation-emission matrices and synchronous fluorescence spectra.