The oxidation of glucose by Pseudomonas aeruginosa is known to follow the sequence: glucose→ gluconic acid→2-ketogluconic acid→pyruvic acid and thence into the tricarboxylic acid cycle. The most striking aspect of this pathway is that the first two oxidative steps do not involve phosphorylated intermediates at the substrate level. In the present study radioactive phosphorus was used in an attempt to elucidate the carbohydrate metabolism of P. aeruginosa. Cell free preparations of P. aeruginosa, obtained by crushing a cell paste in the Hughes press, incubated with added cofactors, ADP and P³² resulted in the formation of labelled ADP and ATP. The presence of glucose or succinate in the reaction mixture greatly depressed the amount of ATP found. The cell free preparations were found to yield ATP as measured in the hexokinase trap, but the formation of ATP was not increased by the addition of glucose, gluconic acid, 2-ketogluconic acid or succinic acid. These results suggested that no net energy was gained by the extract by the oxidation glucose→ gluconic acid→ 2-ketogluconic acid. In manometric experiments it was found that the cell free preparation did not oxidize glucose-6-phosphate, ribose-5-phosphate, α-ketoglutarate, citrate and isocitrate. Glucose was oxidized with the uptake of two atoms of oxygen per mole of substrate. In the presence of ATP, glucose was oxidized with the uptake of only one atom of oxygen. Gluconic acid and gluconolactone were oxidized with the uptake of one atom of oxygen; ATP had no effect on these last two oxidations. From these data two reactions beyond 2-ketogluconate have been postulated. [Formulas omitted] / Science, Faculty of / Microbiology and Immunology, Department of / Graduate

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Thesis (M.Sc.) --University of Adelaide. / Typewritten copy.

Poultry manure is a useful nutrient source but recently it has raised environmental concern due to possible P movement from P saturated soils to waterbodies. This study was conducted to determine the effects of using phytase and high available phosphorous corn diets on the solubility and plant uptake of P, Cu, and Zn in poultry manure and soils amended with manure. Five diet treatments were used in the study: 1) normal phytic acid corn and 0.135% inorganic P (NPA), 2) normal phytic acid corn, 600 units phytase, and 0.135% inorganic P (NPA+Phytase), 3) normal phytic acid corn and 0.345% inorganic P (NPA+P), 4) high available phosphorous corn and 0.135% inorganic P (HAP), 5) high available phosphorous corn, 600 units phytase, and 0.135% inorganic P (HAP+Phytase). The NPA+P diet and NPA+Phytase diets are most similar to the conventional and alternative phytase supplemented diets currently used commercially. Three Virginia soils (Groseclose, Cecil, Mahan) were amended with manure from the diet treatments at rates of 25 and 50 g/kg and P and Cu were extracted with 0.01 M CaCl2 and Mehlich III extractant after incubation periods of 6 and 12 months. Corn was grown in a greenhouse experiment using these same Virginia soils and sand amended with 8.96 Mg/ha poultry manure from each of the five diet treatments. Poultry manure was nonsequentially extracted for determination of P, Cu, and Zn fractions. Comparing the alternative NPA+Phytase, HAP, and HAP+Phytase treatments to the conventional NPA+P treatment on an N- (nitrogen) basis all reduced both CaCl2 and Mehlich III-soluble P concentrations (P<0.05). Comparing these same treatments on a P-basis increased P extracted with CaCl2 24, 26, and 37%, respectively, and P extracted with Mehlich III P 5, 4, and 9%, respectively (P<0.05). The alternative NPA+Phytase and HAP+Phytase treatments increased water-soluble Cu compared to the conventional NPA+P on both a N- and P-basis, while no differences were observed in Mehlich III solubility between these treatments (P<0.05). The alternative NPA+Phytase treatment did not differ in Pand Cu in corn tissue or plant uptake when compared to the NPA or NPA+P (N- or P-basis) treatments. No difference in Zn in corn tissue was observed between these treatments on a N-basis, while NPA+Phytase was higher on a P-basis. Plant uptake of Zn was higher in the NPA+Phytase treatment compared to the NPA+P treatment on both a N- and P-basis. Addition of phytase reduced P solubility from all reagents except for CaCl2 (P<0.05). Replacing the conventional NPA+P treatment for the alternative NPA+Phytase treatment resulted in higher Cu concentrations for all reagents except for K-pyrophosphate and nitric acid. This same replacement increased Zn extracted by water, CaCl2, and CaNO3, while it reduced Zn extracted by HCl, acetic acid, PbNO3, K-pyrophosphate, and NH4-oxalate in the light. The use of phytase decreased P solubility from manure amended soils when treatments are compared on an equal N-basis, and increased P solubility when compared on an equal P-basis. No effect on plant uptake of P or Cu occurredfrom the NPA+Phytase treatment. / Master of Science

Thesis (Ph.D.) - University of St Andrews, May 2007. / Restricted until 3rd May 2012.

Young Wistar female rats weaned at 25 days were placed on a control diet, or a diet extremely deficient in phosphorus but adequate in all other respects. After five weeks on the diet they were injected with 10 microcuries of high specific activity radiocalcium. The animals were killed at varying periods after injection and samples of bone, teeth and soft tissues were taken for chemical, radio-isotope, and histological analysis. The phosphorus deficient animals showed a marked demineralization of the skeleton, lower radiocalcium uptake by bone and higher radiocalcium uptake by the teeth. The accretion and resorption rate of bone in the phosphorus deficient animals was markedly reduced. The resorption rate, however, was higher than the accretion rate and accounted for the reduced mineralization of the bone. The femur of the rachitic animal had an exchangeable calcium portion of 13% as compared to 4-8% in the control animal. The teeth of the phosphorus deficient animal showed a reduced accretion and attrition rate, and a statistically evident difference in the chemical calcium and phosphorus content. The accretion rate was higher than the attrition rate, so that the teeth remained well mineralized. The depression of the accretion rate was not as marked as that observed in the bone, therefore, the marked demineralization of the rachitic animals' bones was not evident in the teeth. The serum plasma levels for calcium and phosphorus were 9.43 mg.% and 2.86 mg.% in the rachitic animal and 9.91 mg.% and 7.24 mg.% in the control animal. The disappearance of plasma radiocalcium was not as rapid in the rachitic animals. Starvation of phosphorus deficient animals resulted in a lower plasma calcium and raised plasma phosphorus level similar to that observed in parathyroidectomized animals. The soft tissue calcium concentration in the rachitic animals as compared to the control animals was higher for all soft tissues examined with exception of the kidney and blood plasma where there was no significant difference. The amount of calcium in the various muscle compartments was calculated. The rachitic animal had a higher intra-cellular calcium concentration and the same extra-cellular concentration when compared with the control animal. There was no difference in the phosphorus concentration of the control and rachitic animals' soft tissues. Histological studies of the femur of the rachitic and control animal showed that the rachitic femur had a wider epiphyseal cartilage which was not uniform in width. The bone trabeculae showed wide irregular seams of uncalcified osteoid matrix. Histological and calcium analysis of the kidneys of the phosphorus deficient animals showed no evidence of calcium deposits or nephrocalcinosis. Histological studies of the parathyroid glands of rachitic animals showed a decrease, in the volume of the glands, in the size of the nuclear surface, and in the amount of cytoplasm present, when compared to the glands of the control animals. This study of calcium kinetics in the phosphorus deficient animal coupled with the histological findings shows the possibility that phosphorus deficiency in rats produces a hypoparathyroid condition as a homeostatic mechanism to conserve phosphorus for the soft tissues. / Medicine, Faculty of / Cellular and Physiological Sciences, Department of / Graduate

To reduce energy consumption, and to achieve the desired denitrification, the activated sludge process sometimes needs to operate at low dissolved oxygen concentrations. The ASM2d model describes the activated sludge process, if nitrification and denitrification occur during different phases in a sequencing batch reactor (SBR). Despite the widespread study of enhanced biological phosphorous removal, comprehensive sludge floc distribution model remains lacking that would better describe this process. Consequently, the integrated system model has been developed to understand the impact of floc at low DO concentrations, and during the process of biological nitrogen and phosphorous removal. In a wastewater treatment plant used in this study, the dissolved oxygen was controlled at a low concentration, 1.7〖gO_2 m〗^(-3), and the dispersion coefficient into the floc was found to be 〖D=1.2×10〗^(-4) m^2/day. Introduction of a number of effectiveness factors contributed to the development of the ASM2d model described herein. This developed model could be valuable for predicting process behaviours applicable under various configurations. Moreover, parameters and effectiveness factors for the model could be calibrated using a genetic algorithm approach. Optimisation was then achieved by controlling the solids retention time during the activated sludge process.