The aim of this work should be watching and registration of training intensity (kind of oxercise, intent of exercise and registration of responses). With a view to response of change of plasma glukose. The result of this work should be summary of exercises together with response of changes of plasma glukose. The value of this response we have measured, together with a kind of exercise can help trainers and teachers to judge intensity of training. There were four testing subjects in the group we have measured. \\

Bakterien wie Escherichia coli sind immer wieder wechselnden Umweltbedingungen und Nährstoffen ausgesetzt. Aus diesem Grund zeigen sie eine starke Regulation des Kohlenstoff-Metabolismus, um stets die am besten geeignete Nährstoffquelle nutzen zu können. Das Glukose-Phosphotransferase-System (PTS) stellt in E.coli das Hauptaufnahmesystem für Glukose dar und unterliegt damit einer besonderen Regulation. Die Untersuchung der Regulation des Glukose-PTS durch das kleine regulatorische Peptid SgrT war ein Hauptaspekt in dieser Arbeit. Das so genannte SgrRST-System wurde bereits von anderen Arbeitsgruppen als verantwortlich für die Regulation der Expression und Aktivität des Glukose-Transportproteins EIICBGlc (Gen ptsG) unter Glukose-6-Phosphatstress identifiziert. Sie konnten einen durch SgrR aktivierten und durch sgrS (sRNA) vermittelten spezifischen Abbau der ptsG-mRNA zeigen und zudem das von sgrS kodierte Protein SgrT nachweisen (Wadler und Vanderpool, 2007). Dabei waren der Mechanismus und die Funktion von SgrT bei der Regulation des Glukose-PTS bislang unklar. In dieser Arbeit konnte zum ersten Mal eine direkte Protein-Protein-Wechselwirkung zwischen SgrT und dem Membranprotein EIICBGlc durch in vitro- und in vivo-Methoden nachgewiesen werden. Dabei wurde nicht nur der Nachweis einer Wechselwirkung erbracht, sondern es konnte auch auf Seiten des EIICBGlc eine für die Interaktion der beiden Proteine essentielle Region identifiziert werden. Im hoch konservierten KTPGRED-Motiv des Linkers, welcher die membranständige EIICGlc- und die cytoplasmatische EIIBGlc-Domäne flexibel miteinander verbindet, wurden die Aminosäuren T383, P384, G385, R386 und E387 als Interaktionspartner für SgrT nachgewiesen. Damit wurde der in allen Enterobakterien vorkommenden Sequenz des Linkers in den Glukose- und N-Acetyl-Glukosamin-spezifischen Transportproteinen zum ersten Mal eine Funktion zugewiesen. Zudem wurde ein Modell entwickelt, welches die Funktionsweise von SgrT verdeutlicht. Durch die Bindung des Linkers und die damit verbundene Verhinderung der zum Glukose-Transport notwendigen Konformationsänderung des EIICBGlc, setzt SgrT die Transportaktivität des Membranproteins unter Glukose-6-Phosphatstress drastisch herab. Im Rahmen des FORSYS-Partner Projektes wurde zudem die Auswirkung des SgrRST-Systems auf die Aufrechterhaltung der metabolischen Balance von E.coli in Fermentationsversuchen untersucht. Ein zweites Projekt dieser Arbeit befasste sich mit der Auswirkung der Expression eines chromosomal kodierten EIICBGlc-His auf das Wachstum verschiedener Stämme. Es konnte erfolgreich ein Stamm mit einem ptsGHis-Gen im Chromosom konstruiert und in verschiedenen Versuchen auf z.B. Transportaktivität und Wachstum getestet werden. Des Weiteren wurde ein Stamm mit einem chromosomal kodierten EIICBGlc-His unter der Kontrolle des tacPO kloniert. Durch gezielte IPTG-Zugabe ist das Expressionslevel einstellbar und könnte so in verschiedenen Versuchsansätzen zur Analyse der Auswirkung auf den Metabolismus der Zelle dienen. Auf Grund einer geringen Transportaktivität dieses Stammes wurde eine Suppressionsmutante isoliert, welche einen verstärkten Transport zeigt, bei der sich jedoch das Expressionslevel des EIICBGlc-His nicht mehr vollständig herabsetzen lässt. Eine Optimierung beider Stämme ist demnach erforderlich.

Das RS1 Protein (Gen RSC1A1) beteiligt sich an der Regulation des Na+-D-Glukose-kotransporters SGLT1 und einiger anderer Transporter. In subkonfluenten LLC-PK1 Zellen hemmt RS1 die Freisetzung von SGLT1 aus dem trans-Golgi-Netzwerk und die Transkription von SGLT1. Während es sich in konfluenten Zellen hauptsächlich im Zytoplasma befindet, ist RS1 in subkonfluenten Zellen im Kern und im Zytoplasma lokalisiert. In der vorliegenden Arbeit wurden Mechanismus und Regulation der konfluenzabhängigen Kernlokalisation von RS1 untersucht. Dabel konnte gezeigt werden, dass die von Konfluenz abhängige Kernlokalisation von RS1 durch den Zellzyklus reguliert wird. In RS1 aus Sus scrofa (pRS1) wurde eine Sequenz identifiziert („nuclear shuttling signal“, NS), die für die konfluenzabhängige Verteilung von RS1 verantwortlich ist und sowohl das Signal für die Kernlokalisation (NLS) als auch das Signal für den Export aus dem Kern (NES) beinhaltet. Die NLS und NES Signale von RS1 vermitteln die Translokation des Proteins in den Kern und aus dem Kern mit Hilfe von Importin β1 bzw. CRM1, wobei die Verteilung von RS1 zwischen Kern und Zytoplasma durch die Aktivität des Exportsystems bestimmt wird. Es wurde gezeigt, dass die benachbarte Proteinkinase C (PKC) Phosphorylierungsstelle an Serin 370 von pRS1 die NS-gesteuerte Kernlokalisierung kontrolliert und für die vom Zellzyklus abhängige Kernlokalisation notwendig ist. Aufgrund der Ergebnisse der ortsgerichteten Mutagenese, PKC-Aktivierungsexperimenten und Massenspektrometrie-Analyse des Phosphorylierungsmusters von RS1 wurde ein Modell vorgeschlagen, das die Regulation der Kernlokalisation des RS1 Proteins in LLC-PK1 Zellen beschreibt. Dem Modell zufolge wird RS1 in subkonfluenten Zellen stark in den Kern befördert, während der Export von RS1 aus dem Kern nicht stattfindet. Das führt zur Anreicherung von RS1 im Kern. Nach Konfluenz wird Serin 370 durch PKC phosphoryliert, was die Steigerung des RS1-Exports aus dem Kern begünstigt und die überwiegend zytoplasmatische Lokalisation des Proteins in konfluenten Zellen hervorruft. Die konfluenzabhängige Regulation der Lokalisation von RS1 kann die Expression von SGLT1 während der Regeneration von Enterozyten im Dünndarm und der Regeneration von Zellen der Nierentubuli nach hypoxämischem Stress kontrollieren. Außerdem deutet die Analyse der Genexpression in embryonalen Fibroblasten der RS-/- Mäuse deutet darauf hin, dass die transkriptionale Regulation durch RS1 im Zellzyklus und bei der Zellteilung eine wichtige Rolle spielen kann. Da die Lokalisation von RS1 zellzyklusabhängig ist, kann RS1 für die Regulation der Transporter in spezifischen Phasen des Zellzyklus wichtig sein. / The RS1 protein (gene RSC1A1) participates in regulation of Na+-D-glucose cotransporter SGLT1 and some other solute carriers. In subconfluent LLC-PK1 cells, RS1 inhibits release of SGLT1 from the trans-Golgi network and transcription of SGLT1. In subconfluent cells, RS1 is localized in the nucleus and the cytoplasm whereas confluent cells contain predominantly cytoplasmic RS1. In the present study, the mechanism and regulation of confluence-dependent nuclear location of RS1 was investigated. Confluence dependent nuclear location of RS1 was shown to be regulated by the cell cycle. A nuclear shuttling signal (NS) in pRS1 was identified that ensures confluence-dependent distribution of pRS1 and comprises nuclear localization signal (NLS) and nuclear export signal (NES). The NLS and NES of RS1 mediate translocation into and out of the nucleus via importin ß1 and CRM1, respectively, and the nuclear/cytoplasmic distribution of the RS1 protein is determined by the nuclear export activity. The adjacent protein kinase C (PKC) phosphorylation site at serine 370 of pRS1 was shown to control nuclear localization driven by NS and is necessary for the differential localization of RS1 in quiescent versus proliferating cells. Basing on the data of site-directed mutagenesis, PKC activation experiments and mass spectrometry analysis of RS1 phosphorylation, the following model of the regulation of RS1 nuclear location in LLC-PK1 cells was proposed. In subconfluent cells, RS1 is actively imported into the nucleus whereas nuclear export of RS1 is not active leading to accumulation of RS1 in the nucleus. After confluence, phosphorylation of serine 370 of pRS1 by PKC takes place leading to enhancement of RS1 nuclear export and predominantly cytoplasmic distribution of the protein in the confluent cells. The confluence-dependent regulation of RS1 localization may control SGLT1 expression during regeneration of enterocytes in small intestine and during regeneration of renal tubular cells after hypoxemic stress. Moreover, the gene expression profiling of mouse embryonic fibroblasts with RS1-/- genotype suggests that transcriptional regulation by RS1 might be important for the cell cycle and cell division. Since RS1 localization depends on the cell cycle, RS1 might play a role in the regulation of the solute carriers during specific phases of the cell cycle.

In dieser Arbeit wurde die Funktionsweise der sauren Histidin-Phosphatasen (HAPs) an zwei Vertretern, der PhyK (Phytase) aus Klebsiella sp. ASR1 und der AgpE (Glukose-1-Phosphatase) aus Enterobacter cloacae, untersucht. Neben den biochemischen Charakterisierungen der beiden Enzyme und deren Substitutionsmutanten konnten die Proteinstrukturen aufgeklärt werden. Die Kokristallisationen mit Phytat bzw. myo-Inositolhexasulfat ermöglichten die Modellierungen der Substratbindungen in den aktiven Zentren. Es konnten für die Glukose-1-Phosphatase AgpE zum ersten Mal zwei Konformationszustände, eine offene und eine geschlossene Form, ähnlich der E. coli Phytase (AppA) gezeigt werden. Ungeachtet deutlicher funktioneller Unterschiede wiesen die AgpE und AppA starke strukturelle Ähnlichkeiten auf. Deshalb wurden gezielte Aminosäuren-Substitutionen im aktiven Zentrum der AgpE durchgeführt, um deren Eigenschaften zu modifizieren. Bereits der Austausch von nur zwei Aminosäuren führte zu einem deutlich veränderten Substratspektrum der AgpE und bewirkte einen weiteren, hier zum ersten Mal gezeigten, Phytatabbau durch eine Glukose-1-Phosphatase. Die PhyK aus Klebsiella sp. ASR1 wurde ebenfalls verschiedenen Substitutionsmutagenesen unterzogen. Hierbei wurden Phytasevarianten erzeugt, die bis zu 20 % höhere spezifische Aktivitäten und damit einen effizienteren Phytatabbau aufwiesen sowie eine deutlich verringerte Substrathemmung zeigten. Aus den “High Performance Ion Chromatography” Analysen (HPIC) des Phytatabbaus der nativen Klebsiella-Phytase und der Mutanten konnten Rückschlüsse auf die Bedeutung einzelner Aminosäuren für die Substratbindung und daher auch auf den Hydrolysemechanismus gezogen werden. Ausserdem konnte auch gezeigt werden, dass der kombinierte Einsatz der effizienteren Phytasemutante mit der nativen AppA aus E. coli eine deutlich schnellere, vollständige Phytathydrolyse bewirkte und somit einen interessanten Aspekt für die Anwendung in der Tierernährung darstellt. / This work presents the analysis of the enzymatic function of histidine acid phosphatases (HAPs) exemplary studied on two enzymes: the phytase of Klebsiella sp. ASR1 (PhyK) and the glucose-1-phosphatse (AgpE) of Enterobacter cloacae. The AgpE belongs to the HAPs and shows lower catalytic activity for phytate. Besides biochemical analysis the structure of these two enzymes were solved. Binding of phytate and the inhibitor myo-inositolhexa sulfate at the active site of these enzymes were fitted according to the date obtained by co-crystallisations experiments. For the first time two district conformational states could be observed for a glucose-1-phosphatase (AgpE). The open and closed conformations as well as the structures were very similar to the well characterized AppA phytase of E. coli however bothe enzymes showed differences in catalytic efficiency. For this reason substitutions of amino acid within the active site were performed to change substrate spectra and specific activities. The substitutions of only two amino acids strongly changed the substrate spectrum and affected the further phytate hydrolysis by the AgpE. Extensive amino acid substitutions were performed for the phytase of Klebsiella sp. ASR1 as well. In this case phytase mutants with 20% higher specific phytase activities were generated. Besides that, the observed strong substrate-induced inhibitory effect on the phytase activity was lower in these mutants. The biochemical characterizations and high performance ion chromatography analysis (HIPC) of these phytase mutants allowed drawing conclusions of the importance of particular amino acid residues for substrate binding and substrate hydrolysis. Furthermore the combination of Klebsiella phytase mutant and AppA resulted in a more efficient phytate hydrolysis. This aspect offers an interesting possibility for usage of the Klebsiella phytase in livestock breading and animal feeding.

Background: Tumor cells are highly dependent on glucose even in the presence of oxygen. This concept called the Warburg effect is a hallmark of cancer and strategies are considered to therapeutically exploit the phenomenon such as ketogenic diets. The success of such strategies is dependent on a profound understanding of tumor cell metabolism. With new techniques it is now possible to thoroughly analyze the metabolic responses to the withdrawal of substrates and their substitution by others. In the present study we used gas chromatography coupled to mass spectrometry (GC-MS) to analyze how glioblastoma brain tumor cells respond metabolically when glucose is withdrawn and substituted by pyruvate. Methods: Glioblastoma brain tumor cells were cultivated in medium with high (25 mM), medium (11 mM) or low (5.5 mM) glucose concentration or with pyruvate (5 mM). After 24 h GC-MS metabolite profiling was performed. Results: The abundances of most metabolites were dependent on the supply of glucose in tendency but not in a linear manner indicating saturation at high glucose. Noteworthy, a high level of sorbitol production and release was observed at high concentrations of glucose and high release of alanine, aspartate and citrate were observed when glucose was substituted by pyruvate. Intermediates of the TCA cycle were present under all nutritional conditions and evidence was found that cells may perform gluconeogenesis from pyruvate. Conclusions: Our experiments reveal a high plasticity of glioblastoma cells to changes in nutritional supply which has to be taken into account in clinical trials in which specific diets are considered for therapy.

This study examined the energy dependence of cancer cells. Glucose was found to be their main energy source. It seems possible to use this dependence to advantage in the fight against cancer. A novel experiment to reduce the blood glucose supply and utilisation was proposed. It entailed caloric restriction, suppression of glucose secretion by the liver as well as suppression of stress hormones (which elevates glucose levels). This minimises the blood glucose value. As a last step, anti-insulin is provided to inhibit cancer cells to utilise the glucose. The cancer cells are thus deprived of their main energy source. This should lead to a reduction or elimination of tumours and will aid in preventing their development. Although feasible, this method turned out to be too expensive to perform the necessary clinical trials to prove the hypothesis. Next, the focus shifted to cancer prevention. The human energy system was analysed with the goal to reduce the circulating glucose level. The main focus here was metabolised CHO energy consumption. A previously proposed unit – the Equivalent Teaspoon Sugar, or ets , was used to quantify energy with. It was shown that cancer risk increases significantly when the recommended ets consumption per day is exceeded. Furthermore, it was shown that including fibre in a meal reduces the ets value of the meal. One gram of fibre leads to a reduction of around 0.6 ets . The link between exercise, stress, fibre, their resulting blood glucose levels and cancer were quantified in terms of ets . Exercise expends ets , while stress causes the liver to secrete more ets . Experimental data was analysed to confirm the relationships. In conclusion an equation was formulated to describe the combined effect of all these elements on the energy system. One’s total daily ets consumption can be obtained from the equation, and it was linked to one’s cancer risk. Adapting a lifestyle that ensures the correct daily ets intake will lead to a significant reduction in cancer risk. This study proved that cancer cells are very dependent on sugar and a restriction of this energy source forces them into regression. Using this knowledge to advantage may help in the combat one of the biggest killers of our time – cancer. / Thesis (Ph.D. (Electrical and Electronic Engineering))--North-West University, Potchefstroom Campus, 2012

This study examined the energy dependence of cancer cells. Glucose was found to be their main energy source. It seems possible to use this dependence to advantage in the fight against cancer. A novel experiment to reduce the blood glucose supply and utilisation was proposed. It entailed caloric restriction, suppression of glucose secretion by the liver as well as suppression of stress hormones (which elevates glucose levels). This minimises the blood glucose value. As a last step, anti-insulin is provided to inhibit cancer cells to utilise the glucose. The cancer cells are thus deprived of their main energy source. This should lead to a reduction or elimination of tumours and will aid in preventing their development. Although feasible, this method turned out to be too expensive to perform the necessary clinical trials to prove the hypothesis. Next, the focus shifted to cancer prevention. The human energy system was analysed with the goal to reduce the circulating glucose level. The main focus here was metabolised CHO energy consumption. A previously proposed unit – the Equivalent Teaspoon Sugar, or ets , was used to quantify energy with. It was shown that cancer risk increases significantly when the recommended ets consumption per day is exceeded. Furthermore, it was shown that including fibre in a meal reduces the ets value of the meal. One gram of fibre leads to a reduction of around 0.6 ets . The link between exercise, stress, fibre, their resulting blood glucose levels and cancer were quantified in terms of ets . Exercise expends ets , while stress causes the liver to secrete more ets . Experimental data was analysed to confirm the relationships. In conclusion an equation was formulated to describe the combined effect of all these elements on the energy system. One’s total daily ets consumption can be obtained from the equation, and it was linked to one’s cancer risk. Adapting a lifestyle that ensures the correct daily ets intake will lead to a significant reduction in cancer risk. This study proved that cancer cells are very dependent on sugar and a restriction of this energy source forces them into regression. Using this knowledge to advantage may help in the combat one of the biggest killers of our time – cancer. / Thesis (Ph.D. (Electrical and Electronic Engineering))--North-West University, Potchefstroom Campus, 2012

Motivation Hypertension and type 2 diabetes mellitus are common in the black population of South Africa. The literature also shows that elevated blood glucose concentrations can lead to an increase in blood pressure and a blunted decline in nocturnal blood pressure. Therefore, the motivation for this study was to determine if blood glucose may play a role regarding the blunted nocturnal decline in blood pressure in African and Caucasian men. Aim The aim of this study was to investigate the relationship between a blunted nocturnal decline in blood pressure and blood glucose in African and Caucasian men. Methodology A comparative population study was preformed that consisted of 202 school teachers (101 African and 101 Caucasian) between the ages of 25–60 years from the North West Province, South Africa. Subjects were excluded if their body temperature was elevated, had a dependence or abuse of psychotropic substances, were regular blood donors and/or vaccinated in the previous three months. Ambulatory systolic (SBP) and diastolic blood pressure (DBP) were measured. Blood samples from the antebrachial vein were collected in sodium fluoride tubes to determine the serum glucose level and glycosylated hemoglobin A1c (HbA1c) percentage. Estimated average glucose (eAG) was determined from the percentage HbA1c by means of a regression formula. Means and proportions were compared by standard t–test and the chi–square test, respectively. Pearson correlations were used to determine unadjusted associations and multiple regression analysis to determine adjusted associations between variables. Results and Conclusion African men had an elevated HbA1c (p<0.001), eAG (p<0.001), nighttime SBP (p<0.001) and DBP (p<0.001). These results remained similar when non–dipping African and Caucasian men were compared. The Africans also smoked more (p=0.012), consumed more alcohol (p=0.049), had a higher percentage of non–dippers (p=0.054), HIV infected subjects (p<0.001) and a larger number of subjects that used anti–hypertensive medication (p=0.049). The unadjusted analysis showed positive correlations between all the blood pressure measurements and serum glucose, HbA1c and eAG in the African non–dipper men. While in the non–dipper Caucasian men, only daytime SBP and nighttime SBP (22:00–06:00) correlated positively with serum glucose, HbA1c and eAG. Furthermore, when viewing the relationship between carotid intima–media thickness (CIMT) and the blood pressure measurements in the African population, only nighttime (00:00– 04:00) SBP (r=0.581, p<0.001) and DBP (r=0.566, p<0.001) showed positive associations. After adjustments were made for age and body mass index the associations between the various blood pressure measurements and blood glucose disappeared in the non–dipper Caucasian men. However, in the non–dipper African men both nighttime (22:00–06:00) SBP and (00:00– 04:00) SBP showed positive correlations with serum glucose, HbA1c and eAG. After full adjustments (age, BMI, smoking, alcohol intake, physical activity, C–reactive protein and baroreceptor sensitivity) were made, nighttime (00:00–04:00) SBP was the only measure of blood pressure that correlated positively with HbA1c (p=0.069) and eAG (p<0.001) in the nondipper African men. No significant relationships were found for Caucasian men. Furthermore, to determine if the association between nighttime (00:00–04:00) SBP and eAG were independent of CIMT, we adjusted for CIMT. By doing so the positive association between SBP and eAG remained significant in the non–dipper African men (R2=0.617; =0.438; p=0.008) and nonsignificant in the non–dipper Caucasian men (R2=0.423; =0.169; p=0.33). However, the relationship between CIMT and eAG disappeared when we adjusted for SBP, suggesting that the SBP and eAG relationship drives CIMT. In conclusion, the association between the early morning SBP (00:00–04:00) and the blood glucose in non–dipping African men suggests that the blunted decline in nocturnal blood pressure during the early morning hours is associated with chronically elevated blood glucose. / Thesis (M.Sc. (Physiology))--North-West University, Potchefstroom Campus, 2011.

Motivation Hypertension and type 2 diabetes mellitus are common in the black population of South Africa. The literature also shows that elevated blood glucose concentrations can lead to an increase in blood pressure and a blunted decline in nocturnal blood pressure. Therefore, the motivation for this study was to determine if blood glucose may play a role regarding the blunted nocturnal decline in blood pressure in African and Caucasian men. Aim The aim of this study was to investigate the relationship between a blunted nocturnal decline in blood pressure and blood glucose in African and Caucasian men. Methodology A comparative population study was preformed that consisted of 202 school teachers (101 African and 101 Caucasian) between the ages of 25–60 years from the North West Province, South Africa. Subjects were excluded if their body temperature was elevated, had a dependence or abuse of psychotropic substances, were regular blood donors and/or vaccinated in the previous three months. Ambulatory systolic (SBP) and diastolic blood pressure (DBP) were measured. Blood samples from the antebrachial vein were collected in sodium fluoride tubes to determine the serum glucose level and glycosylated hemoglobin A1c (HbA1c) percentage. Estimated average glucose (eAG) was determined from the percentage HbA1c by means of a regression formula. Means and proportions were compared by standard t–test and the chi–square test, respectively. Pearson correlations were used to determine unadjusted associations and multiple regression analysis to determine adjusted associations between variables. Results and Conclusion African men had an elevated HbA1c (p<0.001), eAG (p<0.001), nighttime SBP (p<0.001) and DBP (p<0.001). These results remained similar when non–dipping African and Caucasian men were compared. The Africans also smoked more (p=0.012), consumed more alcohol (p=0.049), had a higher percentage of non–dippers (p=0.054), HIV infected subjects (p<0.001) and a larger number of subjects that used anti–hypertensive medication (p=0.049). The unadjusted analysis showed positive correlations between all the blood pressure measurements and serum glucose, HbA1c and eAG in the African non–dipper men. While in the non–dipper Caucasian men, only daytime SBP and nighttime SBP (22:00–06:00) correlated positively with serum glucose, HbA1c and eAG. Furthermore, when viewing the relationship between carotid intima–media thickness (CIMT) and the blood pressure measurements in the African population, only nighttime (00:00– 04:00) SBP (r=0.581, p<0.001) and DBP (r=0.566, p<0.001) showed positive associations. After adjustments were made for age and body mass index the associations between the various blood pressure measurements and blood glucose disappeared in the non–dipper Caucasian men. However, in the non–dipper African men both nighttime (22:00–06:00) SBP and (00:00– 04:00) SBP showed positive correlations with serum glucose, HbA1c and eAG. After full adjustments (age, BMI, smoking, alcohol intake, physical activity, C–reactive protein and baroreceptor sensitivity) were made, nighttime (00:00–04:00) SBP was the only measure of blood pressure that correlated positively with HbA1c (p=0.069) and eAG (p<0.001) in the nondipper African men. No significant relationships were found for Caucasian men. Furthermore, to determine if the association between nighttime (00:00–04:00) SBP and eAG were independent of CIMT, we adjusted for CIMT. By doing so the positive association between SBP and eAG remained significant in the non–dipper African men (R2=0.617; =0.438; p=0.008) and nonsignificant in the non–dipper Caucasian men (R2=0.423; =0.169; p=0.33). However, the relationship between CIMT and eAG disappeared when we adjusted for SBP, suggesting that the SBP and eAG relationship drives CIMT. In conclusion, the association between the early morning SBP (00:00–04:00) and the blood glucose in non–dipping African men suggests that the blunted decline in nocturnal blood pressure during the early morning hours is associated with chronically elevated blood glucose. / Thesis (M.Sc. (Physiology))--North-West University, Potchefstroom Campus, 2011.

Legionella pneumophila ist ein Gram-negatives, ubiqitär verbreitetes Proteobakterium, das als Auslöser der Legionärskrankheit gilt. Die Ergebnisse dieser Arbeit bestätigen, dass Serin eine wichtige Kohlenstoffquelle für Aminosäuren darstellt und dass L. pneumophila für die Aminosäuren Isoleucin, Leucin, Phenylalanin, Tyrosin, Histidin, Prolin und Valin auxotroph ist. Innerhalb der Replikationsvakuole greift L. pneumophila auf Aminosäuren des Wirts zurück und inkorporiert diese in Proteine. Die untersuchte Spezies besitzt die Fähigkeit zur de novo-Biosynthese von Serin. Die vorliegende Arbeit zeigt zudem erstmals, dass Glukose für die Biosynthese von Aminosäuren sowie Polyhydroxybutyrat (PHB) verwendet wird. Der Entner-Doudoroff-Weg (EDW) kann als Haupt-Katabolismusroute von Glukose identifiziert werden. Ein Deletionsstamm des EDW zeigt gegenüber dem Wildtypstamm in nährstoffarmer Umgebung deutlich verminderte Fitness nach erfolgreicher Replikation innerhalb A. castellanii. Die Glukoamylase GamA wird in dieser Arbeit erstmals als verantwortliches Enzym für die Stärke- und Glykogenhydrolyse von L. pneumophila charakterisiert. Der putative Transkriptionsaktivator YozG bindet sowohl im 5’-DNA-Bereich von gamA als auch im eigenen putativen Promotorbereich und reguliert die Hydrolyseaktivität von GamA. Es werden zudem Argumente für die Hypothese erbracht, dass YozG auch als cis-aktives Element fungiert. Die Biosynthese von Polyhydroxybutyrat (PHB) aus Glukose findet während des spät-exponentiellen Wachstums statt und steigert sich in der stationären Phase. Eine verminderte PHB-Menge im EDW-Deletionsstamm wird als Erklärung für die verminderte Fitness in nährstoffarmer Umgebung diskutiert. Die Ergebnisse dieser Arbeit zeigen, dass L. pneumophila neben Aminosäuren auch Glukose sowie die natürlich vorkommenden Glukosepolymere Glykogen und Stärke als Kohlenstoffquellen zur Biosynthese von Aminosäuren und PHB nutzt und dass diese Synthese zur Fitness der Spezies beiträgt. / Legionella pneumophila is a Gram-negative proteobacterium causing Legionnaires’ disease. The results of this study confirm that serine is a carbon source for amino acids and that L. pneumophila is auxotrophic for the amino acids isoleucine, leucine, phenylalanine, tyrosine, histidine, proline, and valine. L. pneumophila uses amino acids of the host cells to incorporate them into proteins. Serine is synthesized de novo. Furthermore, this work demonstrates for the first time that glucose is used for the biosynthesis of amino acids and polyhydroxybutyrate (PHB). The Entner-Doudoroff pathway is identified as the predominant pathway for the catabolism of glucose. In a nutrient-depleted environment, after replication has taken place in A. castellanii, a deletion strain of the Entner-Doudoroff pathway exhibits strongly reduced fitness as compared to the wildtype. The glucoamylase GamA is characterized as the enzyme responsible for the starch and glycogen degrading activity of L. pneumophila for the first time. The putative transcription activator YozG binds to the 5’ region of gamA as well as to his own putative promoter region and regulates GamA activity. Furthermore, arguments are provided to support the hypothesis that YozG also acts as a cis-active element. The biosynthesis of polyhydroxybutyrate (PHB) from glucose starts in the late exponential phase and increases in the stationary growth phase. As an explanation for reduced fitness of the Entner-Doudoroff deletion strain in nutrient-depleted environment, a reduced amount of PHB is proposed. The results of this work prove that L. pneumophila uses not only amino acids but also glucose and the natural glucose polymers starch and glycogen as carbon sources for the biosynthesis of amino acids and PHB and that thereby the fitness of the species is increased.