<p>The origin of man has motivated researchers to investigate differences between humans and our non-human relatives. The striking phenotypic differences that distinguish humans from chimpanzees are likely controlled by a relatively modest number of genetic changes present between these species. As energy acquisition and processing effect multiple organ systems, the dramatic changes in the human diet are thought to underpin many of these unique phenotypes. The evolution of the human diet is marked by omnivory with increased consumption of animal products, cereal grain and vegetable oil associated with the Paleolithic era, domestication of plants and the industrial revolution respectively. Nutrition is essential for life and is unique as it both shapes, and is shaped by the genome. Given this complex interaction, teasing out actors and responders in the genome-diet relationship is a challenge. I took several expression approaches by interrogating regulatory regions, candidate networks and genomes in tissues of dietary relevance. These experiments uncovered combinations of physiological and morphological changes between humans and non-human primates. Taken together, the combined power of <italic>in vitro</italic> and <italic>in vivo</italic> approaches elucidates several genetic mechanisms important in uniquely human bioenergetic processes.</p> / Dissertation

This study determined the effects of exercising above (LATabove) and below(LATbelow) the lactate threshold, upon excess post-exercise oxygen consumption (EPOC) magnitude and duration among average fit females. Thirteen females underwent testing over a nine-day period (5 visits). Resting metabolic rate (RMR) was assessed over two days. A ramp cycle test determined peak V02 and LAT. Blood samples, ventilatory, and heart rate measurements were recorded during rest, exercise, and recovery. On separatedays, volunteers exercised 10% LATabove and LATbelow expending 300 kcals. Afterwards,heart rate, RER, and V02 were measured until within ± 5% of the baseline RMR. EPOC duration was significantly greater for LATabove (61.49 + 8.73 min) than LATbelow (30.72 + 4.81 min). EPOC magnitude was also significantly greater LATabove (24.29 + 3.67 kcals) than LATbelow (13.28 ± 2.10 kcals). This study demonstrated exercising at LATabove adds an additional energy cost component to the recovery dynamics. / School of Physical Education

Cytochromes P450 (CYPs) metabolize a vast array of xenobiotics, including many drugs and toxins. Induction or downregulation of the CYPs can have important consequences such as changes in drug efficacy and altered susceptibility to toxicity. Our study investigated the independent and combined effects of ethanol and nicotine on hepatic and/or brain levels of CYP2E1, CYP2B6 and CYP2A6 in African green monkeys. Monkeys were randomized into four groups (N = 10/group): an ethanol-only group, a nicotine-only group, an ethanol + nicotine group and a control (no drug) group. Ethanol (10% ethanol in sucrose solution) was voluntarily self-administered by the monkeys and nicotine was given as subcutaneous injections (0.5 mg/kg bid). Protein levels and/or in vitro activity were assessed in liver and brain tissue. Also, in vivo pharmacokinetics for chlorzoxazone (metabolized selectively by CYP2E1) and nicotine (metabolized primarily by CYP2A6 and to a lesser extent CYP2B6) were assessed. Hepatic CYP2E1 protein levels, in vitro hepatic CYP2E1 activity and in vivo chlorzoxazone metabolism were increased by ethanol and nicotine, alone and in combination. Hepatic CYP2B6 protein levels and in vitro hepatic CYP2B6 activity were increased by ethanol alone or combined ethanol and nicotine exposure, but were unaffected by nicotine alone. Hepatic CYP2A6 protein levels and in vitro hepatic CYP2A6 activity were decreased by nicotine alone or combined ethanol and nicotine exposure, but unaffected by ethanol alone. Chronic nicotine resulted in higher nicotine plasma levels achieved after nicotine administration, consistent with decreased CYP2A6 activity. Ethanol, alone or combined with nicotine, resulted in lower nicotine plasma levels, an effect that was not mediated by changes in CYP activity. Protein levels of CYP2E1 and CYP2B6 were induced in specific regions and cells in the brain as a result of ethanol self-administration, nicotine treatment and the combined exposure to both drugs. In summary, ethanol and nicotine can alter the expression and/or activity of several important CYP2 family enzymes in primate liver and/or brain.

Ten trained subjects were studied during and following exercise to determine the effects of fructose ingestion on muscle glycogen depletion and resynthesis. Three subjects cycled for anhour while the other six subjects completed a 3000-yard swim. The subjects ingested 12 grams of fructose before, 46 grams during, and 12 grams in the 30 minutes following the exercise. Muscle biopsies were obtained before, immediately after, and 12 hours post exercise. In -the cyclists, plasma glucose and insulin were also determined. The ingestion of fructose had no effect on the glycogen depletion during exercise. However, in the 12 hours following exercise, fructose ingestion resulted in a 41.4 mmole/kg-wet tissue increase in muscle glycogen. At the same time, the control period resulted in only a 9.53 mmole/kg-wet tissue increase in muscle glycogen. Plasma glucose and insulin levels increased during the fructose feeding. These data suggest that fructose ingestion during exercise has no effect in sparing muscle glycogen during work, but could significantly enhance the resynthesis of glycogen after work.

No abstract available. / Thesis (Ph.D.)-University of Natal, Pietermaritzburg, 1975.

It was estimated that more than one hundred open reading frames in Pyrococcus furiosus and Thermotoga maritima could encode flavoproteins based on the results of motif search and comparison of genomic annotation to the experimentally characterized flavoproteins. However, only a few flavoproteins have been characterized from those anaerobic hyperthermophiles. It was found T. maritima and Thermotoga hypogea were able to grow in the presence of micromolar level of oxygen. As part of an oxygen removal system, the presence of NADH oxidase was detected in both microorganisms. In T. hypogea, NADH oxidase activity was constant regardless of the presence of oxygen, while in T. maritima it was increased in the presence of oxygen. The purified T. hypogea NADH oxidase was a flavin adenine dinucleotide (FAD)-containing homodimer with subunit molecular mass of 50 kDa. In addition to NADH oxidase activity, it also demonstrated activity of dihydrolipoamide dehydrogenase (DLDH), which is probably involved in glycine decarboxylation. The purified NADH oxidase from T. maritima was a heterodimeric protein of two subunits with molecular weight of 54 and 46 kDa, which were identified to be encoded by TM1432 and TM1433, respectively. Each subunit bore one FAD and the large subunit had one bacterioferritin-associated ferredoxin (BFD)-like [2Fe-2S]-center. Although the T. maritima NADH oxidase had very unusual oxygen sensitivity, the oxygen inactivated enzyme could be fully recovered by incubating with reducing reagents anaerobically. The NADH oxidases from both T. hypogea and T. maritima catalyzed the reduction of oxygen only to hydrogen peroxide. NADH-dependent peroxidase activities were detected in both T. maritima and T. hypogea, suggesting the presence of a multi-component oxygen detoxification system in Thermotoga species. In addition to its NADH oxidase activity, the enzyme from T. maritima exhibited FAD-linked glycerol-3-phosphate dehydrogenase (FAD-GPDH) activity. Along with the glycerol kinase, the FAD-GPDH took part in glycerol utilization in T. maritima. Ferredoxin NAD+ oxidoreductase (FNOR) activity was detected in T. maritima using an NADH:benzyl viologen oxidoreductase (BVOR) assay. The purified enzyme was a homodimeric FAD-containing protein with subunit molecular mass of 37 kDa. The purified enzyme was very active in catalyzing the reduction of BV and methyl viologen (MV) using either NADH or NADPH as electron donor and could indeed catalyze the reduction of NAD+ with the reduced ferredoxin from T. maritima. The purified enzyme was further identified to be encoded by TM0869 and annotated as thioredoxin reductase (TrxR). T. maritima TrxR could not use commercially available thioredoxin (Trx) from Spirulina, but the Trx purified from T. maritima. T. maritima Trx was identified to be encoded by TM0868 and annotated as glutaredoxin (Grx)-like protein, which showed both thioredoxin (Trx) and Grx activity. The purified T. maritima TrxR could catalyze the Trx-dependent reduction of both insulin and DTNB using NAD(P)H as electron donor. The identified Trx-TrxR system in T. maritima is the first one characterized in hyperthermophilic bacteria. T. hypogea has great potential in microbial hydrogen production. The key enzyme involved in this process, hydrogenase, has not been studied yet. The growth-dependent hydrogenase activity was detected in T. hypogea, from which a homotetrameric hydrogenase was purified. The purified T. hypogea hydrogenase did not contain any flavin prosthetic group as speculated, but [Fe-S]-centers. The hydrogenase could catalyze both BV and MV-dependent hydrogen oxidation and MV-dependent hydrogen evolution. Neither NAD(P)H nor NAD(P) could be used as electron carrier for this enzyme. T. hypogea hydrogenase could utilize ferredoxin as electron carrier for both production and oxidation of hydrogen, which suggests that the purified hydrogenase plays an important role in hydrogen metabolism of T. hypogea. It was concluded that flavoproteins can be involved at least in several very important cellular processes such as detoxification of oxygen, utilization of glycerol, redox regulation, and hydrogen metabolism in hyperthermophiles.

Maternal ethanol consumption during pregnancy can produce teratogenic outcomes in offspring, which are collectively termed Fetal Alcohol Spectrum Disorder (FASD). Central nervous system (CNS) dysfunction is a debilitating and permanent manifestation of FASD. Recent studies indicate that chronic prenatal ethanol exposure (CPEE), via maternal ethanol administration, also impairs metabolic function in offspring. The mechanism of ethanol teratogenicity is multi-faceted and could involve alterations in insulin and insulin-like growth factor (IGF) signaling pathways. These pathways are not only important for metabolism, but are also involved in CNS neuronal survival and plasticity, which are impaired by CPEE. The overall goal of this thesis research was to study, in the guinea pig, neurobehavioural and metabolic effects of CPEE and to investigate whether these effects were associated with altered CNS and peripheral insulin/IGF signaling pathways. In postnatal offspring, CPEE decreased brain weight and altered performance of the modified Biel-maze task, which was a sensitive measure of apparent cognitive dysfunction and executive function deficits. Furthermore, CPEE produced various manifestations of metabolic teratogenicity in offspring, including decreased birth weight, postnatal catch-up body growth, increased whole-body adiposity, disrupted pancreatic morphology, dysregulation of blood glucose concentration and increased liver weight in adulthood. The CPEE-induced neurobehavioural and metabolic effects were associated with alterations of the insulin/IGF signaling pathways in the CNS and periphery. In the liver, CPEE decreased mRNA expression of IGF-1, IGF-1 receptor, and IGF-2 in male and female offspring, and increased mRNA expression of insulin receptor substrate (IRS)-2 in male offspring only compared with nutritional control. Female CPEE offspring had decreased hepatic mRNA expression of insulin receptor compared with male CPEE offspring. In the prefrontal cortex, IRS-2 mRNA expression was increased in male and female CPEE offspring compared with nutritional control. The studies of this thesis have contributed to the understanding of the neurobehavioural and metabolic consequences of CPEE in offspring, which are associated with impairment of the insulin/IGF signaling pathways. / Thesis (Ph.D, Pharmacology & Toxicology) -- Queen's University, 2014-04-25 10:52:50.048

To gain an understanding of the transcriptional regulation of sucrose transport and metabolism in wheat and to examine their relationships with dry matter accumulation in seeds, this study has characterized the expression patterns of two sucrose transporters (TaSUT1 and TaSUT2) and two sucrose synthase (TaSuSy1 and TaSuSy2) genes in five spring wheat cultivars at different seed developmental stages. Cultivar ‘AC Andrew’ with higher TaSUT1 and TaSuSy2 transcript abundance particularly during the early grain filling stage, exhibited higher dry grain weight than other cultivars. The result, overall, suggests the significance of coordinated expression between TaSUT1 and TaSuSy2 for grain growth. This study also demonstrated the seed specificity of high molecular weight glutenin promoter subunit Dy10, which can be used as an important tool to drive the expression of any sucrose and starch related genes specifically in wheat grains to further our understanding of carbon partitioning and/or increase wheat starch yield.

No description available.

The abi3-1 mutant causes moderate perturbation of seed metabolism relative to wild-type seeds, so offering a distinct and discrete treatment for use in experiments investigating regulation of allocation between sources and sinks. abi3-1 plants continue to initiate new flowers, and hence siliques, for longer than wild-type plants. Total rates of carbon assimilation in the short-term were the same in both genotypes during early reproductive growth. This rate fell to 50-70 % in wild-type plants during later reproductive growth, but did not change in the mutant, consistent with delayed senescence of cauline leaves in abi3-1 plants. It was found that restriction of carbon and/or nitrogen availability restricted growth in both genotypes, and abolished the mutant phenotype. Specific leaf areas increased under shading and decreased when nitrate was limiting. Reduction in nitrate limitation from 90 to 80 % was considerably less limiting for wild-type plant growth, but remained grossly limiting for abi3-1 plants. In previously non-acclimatised plants of both genotypes, no difference was found in assimilation and allocation of ¹⁴C-radiolabel supplied at 200 ppm CO 2. 800 ppm CO 2 similarly had no effect on the wild-type, but caused abolition or inversion of normal source-sink relationships in abi3-1 plants. A significantly large amount of radiolabel was initially incorporated into starch in all tissues in abi3-1 plants, and later moved into the water soluble fraction in each tissue, most likely as sucrose. It is proposed that resource allocation is regulated by competition for resources between sinks maintaining sucrose concentration gradients in the phloem, and that sucrose is both the transport and signalling molecule in the mechanism described. No difference in concentration of sucrose in tissues was found between genotypes, but it was found that mutant siliques imported [U-¹⁴C]glucose into siliques significantly more slowly from the phloem than wild-type siliques. In conclusion, abi3-1 seeds may be seen as having reduced capacity for growth which causes stimulation of floral meristem development by feedback of sucrose in the phloem. Silique initiation is thereby prolonged, creating a demand for assimilates that delays cauline leaf senescence.