The liver maintains energy substrate homeostasis by synchronizing circadian or diurnal expression of metabolic genes with the feeding/fasting state. The activities of hepatic de novo lipogenic gene products peak during feeding, converting carbohydrates into fats that provide vital energy sources for peripheral tissues. Conversely, deregulated hepatic lipid synthesis leads to systemic metabolic dysfunction, establishing the importance of temporal regulation of fat synthesis/usage in metabolic homeostasis. Pharmacological activation of peroxisome proliferator-activated receptor \(\delta / \beta (PPAR \delta / \beta)\)improves glucose handling and systemic insulin sensitivity. However, the mechanisms of hepatic \(PPAR\delta\) actions and the molecular pathways through which it is able to modulate global metabolic homeostasis remain unclear. Here we show that hepatic \(PPAR\delta\) controls the diurnal expression of lipogenic genes in the dark/feeding cycle. Adenovirus mediated liver restricted activation of \(PPAR\delta\) promotes glucose utilization in the liver and fat utilization in the muscle. Liver specific deletion of either \(PPAR\delta\) or the \(PPAR\delta\)-regulated lipogenic gene acetyl-CoA carboxylase 1 (ACC1) reduces muscle fatty acid uptake. Unbiased metabolite profiling identifies 1-stearoyl-2-oleoyl-sn-glycero-3-phosphocholine (SOPC) as a serum lipid derived from the hepatic \(PPAR\delta\)-ACC1 activity that reduces postprandial lipid levels and increases muscle fatty acid uptake. These findings reveal a regulatory mechanism that coordinates lipid synthesis and utilization in the liver-muscle axis, providing mechanistic insights into the hepatic regulation of systemic energy substrates homeostasis.

Amino acids are important modulators of skeletal muscle metabolism, but their impact on glucose uptake by skeletal muscle remains unclear. To address the effect of an amino acid (AA) mixture consisting predominately of isoleucine on glucose uptake we first conducted a dose-response experiment, investigating how different concentrations of the AA mixture affect glucose uptake by isolated rat epitrochlearis muscle. In a subsequent experiment we examined how the AA mixture affects insulin-stimulated glucose uptake by isolated rat epitrochlearis muscle. It was found that the AA mixture with as little as 0.5 mM Ile increases [H3]2-deoxy-D-glucose (2-DG) uptake by 76% compared to basal glucose uptake. The AA mixtures with 1, 2 or 4 mM Ile provided no significant additional effect. Next we combined the AA mixture consisting of 2 mM Ile, 0.012 mM Cys, 0.006 mM Val and 0.014 mM Leu with physiological levels (75 μU/ml, sINS) and maximally-stimulating levels (2 mU/ml, mINS) of insulin. The AA mixture only, sINS and mINS significantly increased 2-DG uptake compared to basal by 63, 79 and 298%, respectively. When the AA mixture was combined with sINS and mINS 2-DG uptake was further increased significantly by 26 and 14%, respectively. Western blotting analysis revealed that compared to basal the AA mixture increased AS160 phosphorylation, while phosphorylation of Akt and mTOR did not change. Combining the AA mixture with sINS resulted in no additional phosphorylation compared to sINS alone. Interestingly, addition of the AA mixture to mINS resulted in increased phosphorylation of mTOR, Akt and AS160 compared to mINS alone. Our results suggest that certain AAs (1) increase glucose uptake in the absence of insulin and (2) augment insulin-stimulated glucose uptake in an additive manner. These effects on glucose uptake appear to be mediated via a molecular pathway that is partially independent from the canonical insulin signaling cascade. / text

Biochars are the product of high temperature treatment of carbonaceous materials with little or no oxygen present, termed “pyrolysis”. Biochars derived from the pyrolysis of biomass feedstocks have proven effective amendments on highly weathered tropical soils. However less is known about their impact on temperate soils and associated crop growth. Moreover, there is inadequate knowledge of the impacts of different biochars produced from different feedstocks under differing pyrolysis conditions. Therefore, a study was conducted to evaluate the effectiveness of different biochars as amendments to improve soil conditions for crop growth, with emphasis on soil fertility and crop nutrition impacts. The response of canola-wheat in rotation to five biochars was evaluated in controlled environment and field experiments conducted on Brown and Black Chernozem soils over a two-year period. Treatments were biochar added at 1 and 2 t ha 1 without and with nitrogen (N) and phosphorus (P) fertilizers at 50 or 100 kg N ha 1 and 25 kg P2O5 ha 1. Parameters evaluated were crop biomass and grain yield, N and P uptake, % recovery of applied N and P, residual soil nutrients (NO3 N, and PO4+ P), pH, electrical conductivity (EC), % organic carbon (% OC) and gravimetric soil moisture. Biochar application resulted in significant increases (p<0.05) in canola yield compared to the control for two fast pyrolysis biochars originating from wheat and flax straw added to the Black Chernozem soil in both studies. No significant response was observed for any of the biochars on the Brown Chernozem. Slow pyrolysis biochar derived from willow feedstock appeared less effective did not show any significant response. Occasional depressions in crop yield were observed in both crops with both soils. In these calcareous Chernozems, biochar did not greatly alter the N and P availability, and its effects on soil pH, % OC, EC and moisture content were small and often non-significant. These results suggest that biochar applications at 1 2 t ha 1 to prairie Chernozemic soils will not have large effects on soil properties or plant growth. Higher rates of application will require development of application technology due to the dusty, powdery nature of the biochar material.

The goal of this work was to characterize avian skeletal muscle (SKM) glucose and fatty acid uptake. English sparrows (Passer domesticus) were used for the following studies: 1. Characterization of glucose uptake, 2. Identification and localization of glucose transporters, 3. Characterization of free fatty acid uptake, and 4. Reciprocal inhibition of glucose and free fatty acids. The results are summarized as follows. Isolated SKM incubated for 60 minutes with insulin, IGF-1, caffeine or AICAR demonstrated no increase in glucose transport. Interestingly, uptake was decreased in the presence of incremental unlabeled glucose suggesting the presence of glucose transporters (GLUT) and by phloretin, an inhibitor of transport proteins, decreased transport. The SKM glycogen content was low, which is supportive of the observed minimal glucose uptake. These findings suggest that GLUT expression may differ in birds as compared to mammals. GLUT1 and GLUT3 gene expression, but not GLUT4, were found in all tissues examined and share a high degree of homology with published chicken sequences. In addition, GLUT3 and GLUT4 proteins were not detected, whereas GLUT1 protein was abundant in blood-tissue barriers. Sparrows have high plasma ketone body levels suggestive of a high rate of free fatty acid (FFA) oxidation. In vitro uptake of radiolabeled oleic acid (OA) was maximal at 60 minutes and competitively inhibited by unlabeled OA suggesting a facilitative process. Radiolabeled OA uptake was not increased by IGF-1, caffeine and AICAR, whereas insulin increased uptake at 60 minutes. Inhibitors of protein-mediated substrate transport increased OA uptake by 60 minutes (DIDS and phloretin) whereas a specific inhibitor of long chain FFA transport, sulfo-N-succinimidyl oleate, decreased its uptake at 2.5 min. In reciprocal inhibition studies, 20mM unlabeled glucose and OA inhibited the uptake of their radiolabeled counterparts. Glucose (20mM) significantly decreased labeled OA uptake 36% and 20mM OA significantly decreased labeled glucose transport by 49%. These data begin to elucidate why avian skeletal muscle may not take up glucose to an appreciable extent and further, why avian skeletal muscle is insulin resistant.

In this literature review the characteristics of two free-floating macrophytes, water hyacinth   (Eichhornia crassipes) and duckweed (Lemna sp.), and two microalgae, Chlorella and Scenedesmus, have been examined regarding their suitability as efficient nutrient removers in the treatment of wastewater with high levels of nutrients and suspended solids from a biogas plant in Loudden. The needs required for the plants to be able to grow in wastewater and the amounts of biomass they can produce have also been studied. The results show that Chlorella is capable of a very high uptake of nutrients in photobioreactors with high nutrient loadings. With an ammonia uptake maximum value at 10900mg/m2/d Chlorella outshines the other organisms in this study. The test organism that performed the closest to Chlorella in terms of nitrogen uptake was water hyacinth with an uptake about 1602mg/m2/d. One factor affecting nutrient uptake in a positive way is the growth rate. Free-floating macrophytes produce more biomass than algae do, and water hyacinth have been shown to be the most productive. It is important to conduct a regular harvest of the plants if a high production should be maintained. High quantity of biomass per unit area can inhibit the growth, and algae are more sensitive to this than the macrophytes often suffering from self-shading when the density is too high. The high level of nutrients in the wastewater prevents growth and dilution is required to achieve any growth at all. Therefore, conventional treatment methods might prove to be a better option.

This thesis is an investigation of photoperiodic injury (PI) in tomato plants and practices to alleviate the problem. PI is a physiological disorder characterized by chlorosis and necrosis of leaves when plants are grown under either long photoperiods or non-24 h light/ dark cycles. Solanum lycopersicum L. (tomato) is particularly susceptible to PI. Our group has shown a correlation between PI and altered circadian expression patterns for the nitrate assimilatory enzymes nitrate reductase (NR) and nitrite reductase (NiR) in tomato, resulting in accumulation of the toxic metabolite nitrite, particularly at specific times of day (TOD) when the NiR/NR activity ratio is low. We hypothesized that accumulation of nitrite and PI can be alleviated by altering nitrate nutrition at specific times of day and the use of an air temperature differential. The tomato cultivars ‘Micro Tom’ (PI-tolerant) and ‘Basket Vee’ (PI-susceptible) were grown under various photoperiod regimes to determine: (1) if a positive correlation exists between PI and nitrite accumulation as determined by visual assessment, and chlorophyll and nitrite quantification; (2) if 24 h light affects the diel pattern of nitrate uptake in a way that favours PI through measurements of nitrate depletion; and (3) if PI can be alleviated by altering nitrate nutrition at two specific TOD when tomato is susceptible to nitrite accumulation. A positive correlation was found between nitrite accumulation and PI. Nitrate uptake experiments showed that the nitrate uptake rate per se is not responsible for PI in tomato, but maintenance of circadian nitrate uptake patterns even in 24 h light in combination with a loss of the circadian patterns for NR and NiR activities could contribute to PI. Nitrite accumulation and PI was decreased by utilizing a nutrient solution containing 25% total nitrogen at two specific 4 h periods in the day when tomato is susceptible to nitrite accumulation. We call this new technique TOD fertigation. Time-of-day fertigation in combination with a 6 oC temperature differential further reduced nitrite accumulation and PI. These findings showed the response of greenhouse tomatoes to supplemental lighting and the potential for increasing the photoperiod threshold for PI. / The Mexican Council for Science and Technology (CONACYT); The Ontario Ministry of Agriculture, Food and Rural Affairs (OMAFRA)

There is some evidence to suggest that oxygen consumption (VO2) and oxygen delivery to muscle are reduced at exercise onset and steady state in individuals with type 2 diabetes (T2D), although no studies have combined measurements of both muscle blood flow and VO2 during exercise in this population. OBJECTIVES: 1) To determine whether a reduction in VO2 during exercise would be accompanied by reduced leg blood flow (LBF). 2) To examine the dynamic response characteristics of LBF to determine whether feedforward and/or feedback control systems of blood flow regulation are impaired. METHODS: Four men with T2D and six healthy, activity matched controls (CON) performed supine, two-leg knee extension/flexion exercise tests involving progressive increase in exercise intensity to exhaustion and step increases to a low intensity equivalent to lifting 7.5 kg (LO7.5kg), and a moderate intensity equivalent to 90% of ventilatory threshold (VT90%). MEASUREMENTS: LBF, VO2, mean arterial pressure, heart rate, and stroke volume were measured continuously. RESULTS: Means ± SE, CON vs. T2D. 1) ∆VO2 was not different between groups during the incremental test (P= 0.264), ∆LBF in T2D tended to be lower (P = 0.098). 2) ∆VO2 was not different between groups at any time during LO7.5kg (P = 0.351). Individuals with T2D demonstrated a lower ∆LBF at time = 15 s (3435.6 ± 275.0 vs. 2120.4 ± 218.4 ml/min, P = 0.018). 3) Gains for baseline (G0) and phase I (G1) LBF adaptation to LO7.5kg were lower in T2D compared to CON (G0: 959.8 ± 111.3 vs. 617.0 ± 22.1 ml/min, P = 0.044; G1: 3662.1 ± 229.0 vs. 2128.1 ± 161.6 ml/min, P = 0.002). 4) The time required to achieve 63% of the total response magnitude tended to be slower in T2D (LO7.5kg: 14.3 ± 1.7 vs. 23.1 ± 4.2 s; VT90%: 26.2 ± 3.5 vs. 40.0 ± 7.5 s; P = 0.095). CONCLUSIONS: 1) The initiatory rise in LBF is significantly lower in individuals with T2D, likely due to impairments in feedforward control mechanisms of blood flow regulation, 2) Individuals with T2D do not demonstrate lower VO2 responses to exercise despite an impaired LBF response. / Thesis (Master, Kinesiology & Health Studies) -- Queen's University, 2009-10-09 17:52:31.708

Mitochondria are dynamic organelles known primarily for their roles in oxidative metabolism and programmed cell death. Both of these processes are regulated by the mitochondrial matrix calcium concentration. Little is known about how mitochondrial calcium is regulated: no plant mitochondrial Ca2+-ATPase pumps or no mitochondrial Ca2+ channels have been identified to date. In addition, little is known concerning any physical interactions between mitochondria and endoplasmic reticulum (ER), an important cellular calcium store, and how these modulate cellular calcium fluxes. In this work stable transgenic Arabidopsis lines expressing fluorescent marker proteins were generated to allow visualisation of mitochondria and the ER in the same cells, and to measure mitochondrial calcium fluxes using aequorin. According to my results, there is a physical association between mitochondria and ER and this association cannot be disrupted by chemical treatments (latrunculin B, methyl viologen and antimycin A). As part of this work I identified an Arabidopsis gene, Mitochondrial Calcium Uptake 1 (MCU1), which encodes a protein with features that suggest a role in mitochondrial calcium dynamics. Fluorescent protein fusions of this protein demonstrated that it localizes to mitochondria. An Arabidopsis T-DNA line was identified with an insertion in MCU1. However, little effect of the insertion on transcript abundance of MCU1 was observed.

Access to abstract is permanently restricted to Ball State communtiy only. / Access to thesis permanently restricted to Ball State community only / School of Physical Education, Sport, and Exercise Science

Hydrogen gas production occurs in permeable reactive iron barriers (PRBs) due to the anaerobic corrosion of granular iron. Once produced, this hydrogen gas can have detrimental physical effects on PRB performance. Corrosion-produced hydrogen may accumulate in pore spaces within the PRB, thereby reducing the porosity and permeability. It may also escape the PRB system, representing a lost electron resource that may otherwise be used in reductive remediation reactions. In addition to these physical effects of hydrogen on PRB performance, chemical interactions between hydrogen and iron also occur. Hydrogen may become absorbed by the iron and stored as an electron resource within lattice imperfections. It may also interact with iron surfaces to influence the corrosion rate of the iron. These chemical interactions between hydrogen and iron may impact the reactivity of the iron granules and therefore affect PRB performance. Currently, the chemical effects of hydrogen on PRB performance remain largely unexplored. In this study, the effect of hydrogen on iron reactivity was investigated by considering hydrogen absorption into iron and hydrogen induced changes to iron corrosion rates. Hydrogen absorption by iron creates a stored electron resource within the iron granules. Release of this stored hydrogen from trapping sites represents an additional electron resource that may be used in contaminant degradation reactions. Therefore, improved hydrogen absorption may contribute to increased iron reactivity. Hydrogen absorption by granular irons has been largely unexplored in PRB performance investigations and the effect of hydrogen absorption on contaminant remediation remains unknown. In this study, an investigation of the factors governing hydrogen absorption by three granular irons, H2Omet56, H2Omet58 and H2Omet86 was conducted. The results demonstrated that rapidly corroding H2Omet86 absorbed hydrogen at a higher rate than the other more slowly corroding irons. The presence of an oxide film on H2Omet56 appeared to improve the proportion of hydrogen absorption compared to the bare irons. Ultrasonic treatment was explored as potential method of release of trapped hydrogen for improved iron reactivity. Ultrasonic treatment appeared to be unsuccessful at releasing stored hydrogen from trapping sites, but further investigations into different ultrasound conditions as well as other methods of hydrogen release could prove useful. Hydrogen gas may also influence iron reactivity by interacting with iron surfaces to alter the corrosion rate of the iron. This may occur by processes such as hydrogen enhanced anodic dissolution, hydrogen induced cracking, enhanced pitting susceptibility and reduction of iron oxides by hydrogen gas. In this study, the effect of hydrogen on iron corrosion rates was assessed by treating two iron materials (H2Omet56 and Connelly) under high pressures of hydrogen for 14 d, then comparing the post-treatment corrosion rates of hydrogen treated irons to the post-treatment corrosion rates of corresponding irons treated under low hydrogen pressures for the same period. The results demonstrated that the post-treatment corrosion rate of high hydrogen treated H2Omet56 iron was lower than the post-treatment corrosion rate of low hydrogen treated H2Omet56 iron. Hydrogen treatment did not appear to affect the post-treatment corrosion rates of Connelly iron. The effect of hydrogen on the corrosion rate of H2Omet56 iron may be a result of hydrogen enhanced anodic dissolution. The presence of a continuous oxide film on Connelly iron appeared to inhibit the effect of hydrogen enhanced anodic dissolution on Connelly iron corrosion rates. The effects of iron oxide reduction by hydrogen and hydrogen induced pitting corrosion were also considered.