Motivation: The prevalence of non-communicable diseases such as diabetes mellitus (DM) and cardiovascular disease (CVD) is rapidly increasing in industrialized societies. Experts believe that lifestyle, and in particular its nutritional aspects, plays a decisive role in increasing the burden of these chronic conditions. Dietary habits would, therefore, be modified to exert a positive impact on the prevention and treatment of chronic diseases of lifestyle. It is believed that the state of hyperglycaemia that is observed following food intake under certain dietary regimes contributes to the development of various metabolic conditions. This is not only true for individuals with poor glycaemic control such as some diabetics, but could also be true for healthy individuals. It would, therefore, be helpful to be able to reduce the amplitude and duration of postprandial hyperglycaemia. Selecting the correct type of carbohydrate (CHO) foods may produce less postprandial hyperglycaemia, representing a possible strategy in the prevention and treatment of chronic metabolic diseases. At the same time, a key focus of sport nutrition is the optimal amount of CHO that an athlete should consume and the optimal timing of consumption. The most important nutritional goals of the athlete are to prepare body CHO stores pre-exercise, provide energy during prolonged exercise and restore glycogen stores during the recovery period. The ultimate aim of these strategies is to maintain CHO availability to the muscle and central nervous system during prolonged moderate to high intensity exercise, since these are important factors in exercise capacity and performance. However, the type of CHO has been studied less often and with less attention to practical concerns than the amount of CHO. The glycaemic index (GI) refers to the blood glucose raising potential of CHO foods and, therefore, influences secretion of insulin. In several metabolic disorders, secretion of insulin is inadequate or impossible, leading to poor glycaemic control. It has been suggested that low GI diets could potentially contribute to a significant improvement of the conditions associated with poor glycaemic control. Insulin secretion is also important to athletes since the rate of glycogen synthesis depends on insulin due to it stimulatory effect on the activity of glycogen synthase. Objectives: Three main objectives were identified for this study. The first was to conduct a meta-analysis of the effects of the GI on markers for CHO and lipid metabolism with the emphasis on randomised controlled trials (RCT's). Secondly, a systematic review was performed to determine the strength of the body of scientific evidence from epidemiological studies combined with RCT's to encourage dieticians to incorporate the GI concept in meal planning. Finally, a systematic review of the effect of the GI in sport performance was conducted on all available literature up to date to investigate whether the application of the GI in an athlete's diet can enhance physical performance. Methodology: For the meta-analysis, the search was for randomised controlled trials with a cross-over or parallel design published in English between 1981 and 2003, investigating the effect of low GI vs high GI diets on markers of carbohydrate and lipid metabolism. The main outcomes were serum fructosamine, glycosylated haemoglobin (HbA1c), high-density lipoprotein cholesterol (HDL-c), low-density lipoprotein cholesterol (LDL-c), total cholesterol (TC) and triacylglycerols (TG). For the systematic review, epidemiological studies as well as RCT's investigating the effect of LGI vs HGI diets on markers for carbohydrate and lipid metabolism were used. For the systematic review on the effect of the GI on sport performance, RCT's with either a cross-over or parallel design that were published in English between January 1981 and September 2004 were used. All relevant manuscripts for the systematic reviews as well as meta-analysis were obtained through a literature search on relevant databases such as the Cochrane Central Register of Controlled Trials, MEDLINE (1981 to present), EMBASE, LILACS, SPORTDiscus, ScienceDirect and PubMed. This thesis is presented in the article format. Results and conclusions of the individual manuscripts: For the meta-analysis, literature searches identified 16 studies that met the strict inclusion criteria. Low GI diets significantly reduced fructosamine (p<0.05), HbA1c, (p<0.03), TC(p<0.0001) and tended to reduce LDL-c (p=0.06) compared to high GI diets. No changes were observed in HDL-c and TG concentrations. Results from this meta analysis, therefore, support the use of the GI concept in choosing CHO-containing foods to reduce TC and improve blood glucose control in diabetics. The systematic review combined the results of the preceding meta-analysis and results from epidemiological studies. Prospective epidemiological studies showed improvements in HDL-c concentrations over longer time periods with low GI diets vs. high GI diets, while the RCT's failed to show an improvement in HDL-c over the short-term. This could be attributed to the short intervention period during which the RCT's were conducted. Furthermore, epidemiological studies failed to show positive relationships between LDL-c and TC and low GI diets, while RCT's reported positive results on both these lipids with low GI diets. However, the epidemiological studies, as well as the RCT's showed positive results with low GI diets on markers of CHO metabolism. Taken together, convincing evidence from RCT's as well as epidemiological studies exists to recommend the use of low GI diets to improve markers of CHO as well as of lipid metabolism. 3 From the systematic review regarding the GI and sport performance it does not seem that low GI pre-exercise meals provide any advantages over high GI pre-exercise meals. Although low GI pre-exercise meals may better maintain CHO availability during exercise, low GI pre-exercise meals offer no added advantage over high GI meals regarding performance. Furthermore, the exaggerated metabolic responses from high GI compared to low GI CHO seems not be detrimental to exercise performance. However, athletes who experience hypoglycaemia when consuming CHO-rich feedings in the hour prior to exercise are advised to rather consume low GI pre-exercise meals. No studies have been reported on the GI during exercise. Current evidence suggests a combination of CHO with differing Gl's such as glucose (high GI), sucrose (moderate GI) and fructose (low GI) will deliver the best results in terms of exogenous CHO oxidation due to different transport mechanisms. Although no studies are conducted on the effect of the GI on short-term recovery it is speculated that high GI CHO is most effective when the recovery period is between 0-8 hours, however, evidence suggests that when the recovery period is longer (20-24 hours), the total amount of CHO is more important than the type of CHO. Conclusion: There is an important body of evidence in support of a therapeutic and preventative potential of low GI diets to improve markers for CHO and lipid metabolism. By substituting high GI CHO-rich with low GI CHO-rich foods improved overall metabolic control. In addition, these diets reduced TC, tended to improve LDL-c and might have a positive effect over the long term on HDL-c. This confirms the place for low GI diets in disease prevention and management, particularly in populations characterised by already high incidences of insulin resistance, glucose intolerance and abnormal lipid levels. For athletes it seems that low GI pre-exercise meals do not provide any advantage regarding performance over high GI pre-exercise meals. However, low GI meals can be recommended to athletes who are prone to develop hypoglycaemia after a CHO-rich meal in the hour prior to exercise. No studies have been reported on the effect of the GI during exercise. However, it has been speculated that a combination of CHO with varying Gl's deliver the best results in terms of exogenous CHO oxidation. No studies exist investigating the effect of the GI on short-term recovery, however, it is speculated that high GI CHO-rich foods are suitable when the recovery period is short (0-8 h), while the total amount rather than the type of CHO is important when the recovery period is longer (20-24 h). Therefore, the GI is a scientifically based tool to enable the selection of CHO-containing foods to improve markers for CHO and lipid metabolism as well as to help athletes to prepare optimally for competitions. Recommendations: Although a step nearer has been taken to confirm a place for the GI in human health, additional randomised, controlled, medium and long-term studies as well as more epidemiological studies are needed to investigate further the effect of low GI diets on LDL-c. HDL-c and TG. These studies are essential to investigate the effect of low GI diets on endpoints such as CVD and DM. This will also show whether low GI diets can reduce the risk of diabetic complications such as neuropathy and nephropathy. Furthermore, the public at large must be educated about the usefulness and application of the GI in meal planning. For sport nutrition, randomised controlled trials should be performed to investigate the role of the GI during exercise as well as in sports of longer duration such as cricket and tennis. More studies are needed to elucidate the short-term effect of the GI post-exercise as well as to determine the mechanism of lower glycogen storage with LGI meals post-exercise. / Thesis (Ph.D. (Dietetics))--North-West University, Potchefstroom Campus, 2005.

Groat oil content and composition are important quality traits in oats (Avena sativa L). These traits are controlled by many genes with additive effects. The chromosomal regions containing these genes, known as quantitative trait loci (QTL), can be discovered through their close association with markers. This study investigated total oil content and fatty acid components in an oat breeding population derived from a cross between high oil ('Dal') and low oil ('Exeter') parents. A genetic map consisting of 475 DArT (Diversity Array Technology) markers spanning 1271.8 cM across 40 linkage groups was constructed. QTL analysis for groat oil content and composition was conducted using grain samples grown at Aberdeen, ID in 1997. QTL analysis for multiple agronomic traits was also conducted using data collected from hill plots and field plots in Ottawa, ON in 2010. QTLs for oil content, palmitic acid (16:0), stearic acid (18:0), oleic acid (18:1), linoleic acid (18:2) and linolenic acid (18:3) were identified. Two of the QTLs associated with oil content were also associated with all of the fatty acids examined in this study, and most oil-related QTL showed similar patterns of effect on the fatty acid profile. These results suggest the presence of pleiotropic effects on oil-related traits through influences at specific nodes of the oil synthesis pathway. In addition, 12 QTL-associated markers (likely representing nine unique regions) were associated with plant height, heading date, lodging, and protein content. The results of this study will provide information for molecular breeding as well as insight into the genetic mechanisms controlling oil biosynthesis in oat.

Submitted by Renata Lopes (renatasil82@gmail.com) on 2016-01-19T10:10:26Z No. of bitstreams: 1 charlesdiasdebrito.pdf: 2413607 bytes, checksum: f1809f4cce1cb76f35fa95ba6b716e99 (MD5) / Approved for entry into archive by Adriana Oliveira (adriana.oliveira@ufjf.edu.br) on 2016-01-25T17:43:32Z (GMT) No. of bitstreams: 1 charlesdiasdebrito.pdf: 2413607 bytes, checksum: f1809f4cce1cb76f35fa95ba6b716e99 (MD5) / Made available in DSpace on 2016-01-25T17:43:32Z (GMT). No. of bitstreams: 1 charlesdiasdebrito.pdf: 2413607 bytes, checksum: f1809f4cce1cb76f35fa95ba6b716e99 (MD5) Previous issue date: 2015-02-24 / CAPES - Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / Neste presente trabalho foi realizado uma busca conformacional dos ácidos graxos esteárico, oleico, palmítico, do álcool glicerol e do triacilglicerol (TAG) que é formado pela junção dos três ácidos citados anteriormente com o glicerol. Tais compostos estão todos situados na gordura do leite bovino [1]. Este foi o maior motivo para os tê-los estudados. Para isso, utilizamos a mecânica molecular (MM), dinâmica molecular (DM) e mecânica quântica (MQ). Foram feitas as otimizações destas moléculas no vácuo e na água. Então, após tais otimizações obtemos seus espectros infravermelho (IR) e RAMAN. Com os resultados obtidos fomos capazes de compará-los aos já existentes na literatura. Podendo estes resultados também, contribuir com informações de propriedades ópticas da gordura do leite bovino a grupos experimentais. Visto que conseguimos um resultado bastante detalhado e satisfatório. / In this present study was performed a conformational search of stearic fatty acids, oleic, palmitic, alcohol glycerol and the triacylglycerol (TAG) that is formed by the junction of the three acids above with glycerol. Such compounds are all situated in bovine milk fat. And this was the biggest reason to have them studied. For this, we use molecular mechanics ( MM ) , molecular dynamics (MD ) and quantum mechanics (QM ). Were made optimizations of these molecules in vacuum and water and then after such optimizations we obtain its infrared (IR) spectra and RAMAN. With the results we were able to compare them with existing in the literature.These results may also, contribute with information of optical properties of bovine milk fat the experimental groups. Since we can a very detailed and satisfactory result.

Triacylglycerols (TAG) or storage oils in plants are utilized by humans for nutrition, production of biomaterials and fuels. Since nonseed tissues comprise the bulk biomass, it is pertinent to understand how to improve their TAG content. Typically, the final step in TAG biosynthesis is catalyzed by diacylglycerol (DAG) acyltransferases (DGAT) and/or phospholipid: diacylglycerol acyltransferases (PDAT), which also determine the content and composition of TAG. Besides enzymatic regulation of TAG synthesis, transcription factors such as WRINKLED1 (WRI1) play a critical role during fatty acid synthesis. In this study, mesocarp of Persea americana, with > 60% TAG by dry weight and oleic acid as the major constituent was used as a model system to explore TAG synthesis in nonseed tissues. Based on the transcriptome data of avocado, it was hypothesized that both DGAT and PDAT are likely to catalyze the conversion of DAG to TAG, and orthologs of WRI1 transcription factors regulate fatty acid biosynthesis. Here, with comprehensive in silico analyses, putative PamDGAT1 and 2 (Pam; Persea americana), PamPDAT1, and PamWRI1 and 2 were identified. When acyltransferases were expressed into TAG-deficient mutant yeast strain (H1246), only DGAT1 restored TAG synthesis capacity, with a preference for oleic acid. However, in planta, when transiently expressed in Nicotiana benthamiana leaves, PamDGAT1, PamPDAT1, PamWRI1, and PamWRI2 increased lipid contents, PamDGAT2 remained inactive. The data reveals that putative PamDGAT1, PamPDAT1 are functional and preferred acyltransferases in avocado and both PamWRI1 and 2 regulate fatty acid synthesis. In conclusion, while nonseed tissue of a basal angiosperm has certain distinct regulatory features, DAG to TAG conversion remains highly conserved.

Les triglycérides (TG) représentent une réserve énergétique essentielle à de nombreuses cellules. De compositions très variées, ils sont le principal constituant de l’huile destinée à l’alimentation, ou utilisée pour produire différents composés d’intérêt industriel. Les Acyl-CoA : diacylglycérol acyltransférases (DGAT) catalysent l’étape finale et limitante de leur synthèse en incorporant un acide gras sur un diglycéride. Chez les végétaux, il existe trois familles, DGAT1, DGAT2 et DGAT3, ne partageant aucune homologie et pour lesquelles aucune structure n’est connue. Ceci empêche toute amélioration de la qualité des huiles par une approche rationnelle. La contribution des DGAT1 à l’accumulation d’huiles alimentaires a été démontrée. Chez certains végétaux, les DGAT2 ont un rôle prépondérant dans lasynthèse de TG peu communs tels que ceux hydroxylés du ricin permettant de produire des lubrifiants et des bioplastiques. La contribution des DGAT3 à la synthèse des TG reste à déterminer in planta.Nous avons étudié les trois familles de DGAT de la plante modèle Arabidopsis thaliana, appartenant à la famille du colza, ainsi qu’une DGAT1 du palmier à huile, plante de culture industrielle. L’expression en bactéries, en levure modèle ou oléagineuse ainsi que l’étude de lignées de plantes mutantes ont permis de caractériser finement les activités de ces enzymes. La modulation de la composition et du contenu en TG des levures par les DGAT a également démontré l’intérêt de ces enzymes pour la production d’huiles microbiennes à façon. / Triacylglycerols (TAG) are an essential energy storage in many cells. Their composition is diverse; they are the main component of the seed oil for the food industry or used to produce industrial compounds. Acyl-CoA: diacylglycerol acyltransferase (DGAT) catalyze the final and rate-limiting step of TAG synthesis by transferring a fatty acid onto a diacylglycerol. In plants, there are three families, DGAT1, DGAT2 and DGAT3, sharing no homology and of unknown structure. It prevents any improvement of seed oil yield and quality by a rational approach. DGAT1 involvement in edible oil accumulation was demonstrated. In some plants, DGAT2 plays a key role in the synthesis of unusual TAG such as hydroxylated TAG found in castor oil and used to produce lubricants and bioplastics. DGAT3 contribution to TAG biosynthesis has not been demonstrated in planta. We studied three families of DGAT from the model plant Arabidopsis thaliana, belonging to the same family as oilseed rape, and a DGAT1 from oil palm, an industrial crop. DGAT expression in bacteria, yeasts and the study of mutant plant lines allowed us to characterize their activities. The modulation of yeast TAG content and composition induced by DGAT expression demonstrated the value of these enzymes for the production of tailored microbial oils.

The biofuel market is dominated by ethanol and biodiesel derived from cellulosic and lipid-based biomass crops. This is largely due to the relatively low costs and reliability of production. At present, production of non-food plant-derived oils for biofuel production in the U.S. is minimal. A research team from the Commonwealth Scientific and Industrial Research Organization (CSIRO), an independent Australian federal government research institution, has developed an efficient transgenic system to engineer oil production in tobacco leaves. This novel system is comprised of multiple transgenes that direct the endogenous metabolic flux of oil precursors towards triacylglycerol (TAG) production. Additional genes were incorporated to store and protect the accumulated oil in vegetative tissues. Preliminary greenhouse tests by the CSIRO research group indicated an oil content of > 30% by dry weight (DW) in tobacco leaf lamina. Here we evaluated two transgenic lines against a non-transgenic control in 2017 and 2018 in greenhouse and field production systems. The 2017 pilot study showed that the high leaf-oil tobacco line was viable and will grow in the field in Kentucky. Chemical analyses revealed significantly higher oil content compared to the non-transgenic control despite several logistical setbacks. These promising discoveries prompted the deployment of additional transgenic line assessments and further data validation in 2018. Line evaluations in 2018 revealed that the LEC2:WRI1:DGAT:OLE transgenic line had the highest leaf oil content (≥ 19.3% DW-1) compared to both the WRI1:DGAT:OLE transgenic line (≤ 5.6% DW-1) and non-transgenic control (≤ 2.1% DW-1). The results of this research will contribute to the successful development of transgenic tobacco lines engineered to accumulate high concentrations of TAG in the leaves.

More human lives have been lost to tuberculosis than to any other disease and despite the availability of effective short course chemotherapy (DOTS) as well as the Bacilli Calmette Guerin (BCG) vaccine, tuberculosis continues to claim more than a million lives annually. Mycobacterium tuberculosis (M. tuberculosis), the causative agent of tuberculosis, is one of the most successful and scientifically challenging pathogens of all time. However in the last two decades, the ability to perform molecular genetic analysis of M. tuberculosis has resulted in powerful new research tools, while the availability of the complete genome sequence has provided us with a wealth of new information and understanding of the biology of this major pathogen. One of the major challenges, however, is to analyze the properties and functions of those genes that are unique to M. tuberculosis genome. The identification and characterization of such genes which impart various survival strategies employed by M. tuberculosis for successful infection will be of particular significance. One of the important outcomes from the complete genome sequence of M. tuberculosis is the discovery of two multigene families designated PE (99 members) and PPE (69 members) named respectively for the Pro-Glu (PE) and Pro-Pro-Glu (PPE) motifs near the N-terminus of their gene products. In addition to these motifs, proteins of the PE family possess highly homologous N-terminal domains of approximately 100 amino acids (PE domain), whereas the PPE proteins possess a highly homologous N-terminal domain of about 180 amino acids (PPE domain). Although the PE and PPE families of mycobacterial proteins are the focus of intense research, no precise function has so far been unraveled for any member of these families. The current study focuses on Rv3097c gene of M. tuberculosis, a PE family gene that was bioinformatically predicted to be a triacylglycerol hydrolase (lipase). In order to decipher the role of the PE domain, we have carried out functional characterization of the Rv3097c gene (also named lipY) as it was, initially, the only known PE protein for which an enzymatic function (i.e. lipase activity) had been predicted. Further, to understand the function of PE family proteins, an important question that needs to be answered is; whether the PE domain of different PE family proteins has similar or different functions? In this context, our studies were focused on studying the functional role of the PE domain in LipY, as outlined below. In general, the in vivo function and subcellular localization of any protein are integrally connected. PE domain has been reported to be essential for cell wall localization of PE_PGRS33, another PE family protein. Therefore we investigated the subcellular localization of LipY and the influence of the PE domain on subcellular localization of LipY. LipY and a truncated form of LipY lacking the PE domain [LipY(ΔPE)] were expressed in mycobacteria(M. smegmatis and M. bovis BCG). Subcellular fractionation and western blot demonstrated that both LipY and LipY(ΔPE) were predominantly detected in the cell wall fraction, indicating that LipY is localized to the cell wall and the PE domain of LipY was not required for translocation of LipY to cell wall. This result is in contrast to the findings for PE_PGRS33, where the absence of the PE domain caused the cell wall associated protein to localize to the cytosol. Furthermore, immuno-electron microscopy of M. bovis BCG expressing LipY(ΔPE) clearly showed a cell surface localization of LipY(ΔPE). These results signify that the function of the PE domain might not always be similar amongst different PE family proteins. In order to further investigate the role of the PE domain in LipY, we studied the lipase activity of LipY and the influence of the PE domain on lipase activity. Bioinformatic analysis confirmed the presence of a lipase domain containing a GDSAG active site motif characteristic of lipases. Overexpression of LipY in mycobacteria (M. smegmatis and M. bovis BCG) resulted in a significant reduction in the pool of triacylglycerols (TAG), consistent with the lipase activity of this enzyme. Interestingly, this reduction was more pronounced in mycobacteria overexpressing LipY(ΔPE), suggesting that the presence of the PE domain diminishes the lipase activity of LipY. In vitro lipase assays also confirmed LipY(ΔPE) as a more efficient lipase compared to the wild-type LipY. Together these results suggest that the PE domain of LipY might be involved in the modulation of lipase activity. Surprisingly, M. marinum, another pathogenic mycobacteria, possesses a protein homologous to LipY, termed LipYmar, in which the PE domain is substituted by a PPE domain. The overexpression of LipYmar in M. smegmatis significantly reduced the TAG pool suggesting that it is a triacylglycerol hydrolase/lipase. Interestingly, similar to the removal of the PE domain of LipY, this reduction in the TAG pool was further pronounced when the PPE domain of LipYmar was removed. This suggests that PE and PPE domains might share similar functional roles in modulating the enzymatic activities of these lipase homologs. In order to assess the in vivo relevance of LipY expression during M. tuberculosis infection, we examined the humoral immune responses against LipY in sera derived from various clinical categories of tuberculosis patients. The presence of specific antibodies against any protein is suggestive of expression of the protein during infection and could potentially be used to differentiate between healthy individuals and infected patients (serodiagnosis of tuberculosis). The cell wall localization suggested that LipY may be accessible for interaction with the host immune system during infection. Moreover, humoral responses were observed against LipY in mice immunized with DNA constructs expressing LipY, indicating that LipY could be an effective B-cell antigen. Accordingly, a strong humoral response against LipY and LipY(ΔPE) was observed in tuberculosis patients compared to healthy individuals, suggesting that LipY is expressed during infection by clinical strains of M. tuberculosis and might represent an immunodominant antigen of M. tuberculosis with potential use in serodiagnosis of tuberculosis.

Metabolic syndrome is a prevalent disease characterized by concurrent manifestation of insulin resistance, obesity, dyslipidemia, hypertension and other hemodynamic and metabolic disorders. It has multifactorial type of inheritance and its resultant phenotype is determined by both environmental and genetic factors as well as their interactions. That is the main reason why comprehensive analysis of the genetic component of this syndrome is complicated in human population. Genetically designed experimental animal models are significant tools for analysis of genetic architecture of human complex conditions including the metabolic syndrome. The aim of this Thesis is utilization of functional and comparative genomic tools to uncover pathogenesis of metabolic syndrome aspects and their genetic determinants. We also studied pharmacogenetic interactions of these genetic determinants with drugs affecting particular components of the metabolic syndrome. Establishing and utilizing several genetically designed congenic rat strains, we undertook four different research projects focusing on pharmacogenetic interaction of all-trans retinoic acid and ondansetron with differential segment of rat chromosome 8, pharmacogenetic interaction of differential segment of rat chromosome 4 and dexamethasone, determining Plzf...

Les Streptomyces sont des bactéries filamenteuses du sol à Gram +. Elles sont connues pour leur capacité à produire des métabolites secondaires utiles en médecine et en agriculture. S. coelicolor et S. lividans sont des souches modèles phylogénétiquement proches. Elles ont cependant des capacités contrastées à accumuler des lipides de réserve de la famille des triacylglycérol (TAG) et produire des métabolites secondaires alors qu’elles possèdent des voies de biosynthèse similaires pour ces deux types de molécules. En présence de glucose, S. coelicolor produit des niveaux élevés de métabolites secondaires spécifiques et son contenu en TAG est faible alors que c'est le contraire chez S. lividans. En revanche, en présence de glycérol, les deux souches accumulent une quantité de TAG similaire mais S. coelicolor produit aussi des métabolites secondaires. Le but de la présente thèse était de déterminer les caractéristiques métaboliques différentielles qui sous-tendent les différentes capacités biosynthétiques de ces deux souches modèles. Pour ce faire, une analyse protéomique comparative sans marquage des souches cultivées en milieu R2YE liquide ou solide en présence de glucose ou de glycérol comme principales sources de carbone a été réalisée en utilisant la technique de chromatographie liquide couplée à de la Spectrométrie de Masse en tandem (LC-MS / MS). Au total, 2024 et 4372 protéines ont été identifiées à partir des cultures liquides et solides, représentant 24% et 50% du protéome théorique. Les études en liquide ont révélé que le métabolisme de S. lividans était principalement glycolytique alors que le métabolisme de S. coelicolor était principalement oxydatif. Elles ont également indiqué que ces caractéristiques pourraient être liées au catabolisme préférentiel des acides aminés par rapport au glucose chez S. coelicolor par rapport à S. lividans. De plus, cette thèse constitue la première analyse protéomique du métabolisme de ces deux souches modèles en présence de glycérol. / Streptomyces are filamentous Gram+ soil bacteria well known for their ability to produce secondary metabolites useful in medicine and agriculture. S. coelicolor and S. lividans are phylogenetically closely-related model strains but they have contrasted abilities to accumulate storage lipids of the TriAcylGlycerol (TAG) family and to produce secondary metabolites whereas they possess similar pathways for the biosynthesis of these molecules. In the presence of glucose, S. coelicolor produces high levels of specific secondary metabolites and its TAG content is low whereas it is the opposite for S. lividans. In contrast, in the presence of glycerol, the two strains accumulated similar amount of TAG but S. coelicolor still produces secondary metabolites. The aim of the present thesis was to determine the differential metabolic features supporting such different biosynthetic abilities. To do so, a comparative label-free shotgun proteomic analysis of the strains grown in liquid or solid R2YE media with glucose or glycerol as main carbon sources was carried out using Liquid chromatography−tandem mass spectrometry (LC−MS/MS). A total of 2024 and 4372 proteins were identified in liquid and solid cultures, representing 24% and 50% of the theoretical proteome, respectively. These studies revealed that S. lividans metabolism was mainly glycolytic whereas S. coelicolor metabolism was mainly oxidative. They also suggested that these features might be related to the preferential catabolism of amino acids over glucose of S. coelicolor compared to S. lividans. Furthermore, this thesis constituted the first proteomic analysis of the metabolism of these two model strains in the presence of glycerol. / Streptomyces es un género de bacterias filamentosas Gram+ provenientes del suelo que son conocidas por su capacidad para producir metabolitos secundarios útiles en la medicina y agricultura. S. coelicolor y S. lividans son cepas modelo filogenéticamente próximas que presentan capacidades opuestas para acumular lípidos de reserva de la familia de los triglicéridos (TAG) y para producir metabolitos secundarios en tanto que ambas cepas poseen rutas metabólicas idénticas para la biosíntesis de éstas moléculas. En presencia de glucosa, S. coelicolor produce altos niveles de metabolitos secundarios específicos y su contenido de TAG es bajo mientras que en S. lividans el comportamiento es opuesto. Sin embargo, en presencia de glicerol, ambas cepas acumulan cantidades similares de TAG y S. coelicolor produce metabolitos secundarios. El objetivo de ésta tesis fue de determinar las características metabólicas que distinguen las diferentes capacidades biosintéticas mencionadas previamente. Por esto, un análisis protéomico comparativo sin marcaje de tipo “shotgun” fue realizado con las dos cepas cultivadas en medio R2YE líquido y sólido usando glucosa o glicerol como fuentes principales de carbono mediante Cromatografía Líquida en “tándem” acoplada a Espectrometría de Masas (LC-MS/MS). Un total de 2024 y 4372 proteínas fueron identificadas en cultivos en medio líquido y sólido, representando 24% y 50% del proteoma teórico, respectivamente. El presente estudio demostró que el metabolismo de S. lividans fue principalmente glicolítico mientras que el metabolismo de S. coelicolor fue principalmente oxidativo. También se sugiere que éstas características pueden estar relacionadas con la preferencia catabólica de aminoácidos sobre el catabolismo de glucosa de S. coelicolor comparada con S. lividans. Además, la presente tesis constituye el primer análisis proteómico del metabolismo de éstas dos cepas modelo en presencia de glicerol.

Metabolic syndrome is a prevalent disease characterized by concurrent manifestation of insulin resistance, obesity, dyslipidemia, hypertension and other hemodynamic and metabolic disorders. It has multifactorial type of inheritance and its resultant phenotype is determined by both environmental and genetic factors as well as their interactions. That is the main reason why comprehensive analysis of the genetic component of this syndrome is complicated in human population. Genetically designed experimental animal models are significant tools for analysis of genetic architecture of human complex conditions including the metabolic syndrome. The aim of this Thesis is utilization of functional and comparative genomic tools to uncover pathogenesis of metabolic syndrome aspects and their genetic determinants. We also studied pharmacogenetic interactions of these genetic determinants with drugs affecting particular components of the metabolic syndrome. Establishing and utilizing several genetically designed congenic rat strains, we undertook four different research projects focusing on pharmacogenetic interaction of all-trans retinoic acid and ondansetron with differential segment of rat chromosome 8, pharmacogenetic interaction of differential segment of rat chromosome 4 and dexamethasone, determining Plzf...