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Item Glucose Uptake by the Cellulolytic Rumen Anaerobe Bacteroides Succinogenes(North Dakota State University, 1986) Franklund, Clifton VictorGlucose uptake by the cellulclytic rumen anaerobe, Bacteroides succinogenes S85, was measured under conditions that maintained anaerobiosis and osmotic stability. This organism was found to possess a highly specific, active transport mechanism for glucose. Evidence for a phosphoenol-pyruvate:g1ucose phosphotransferase system was not detected. Compounds that inhibit electron transport systems (non-heme iron chelators, and sulfhydryl reagents) were effective inhibitors of glucose uptake. The strongest inhibitors were compounds (proton and metal ionophores) that interfere with maintenance of the proton motive force. Compounds which interfere with ATP synthesis also inhibited glucose uptake, but a role for ATP in energizing uptake could not be inferred from these results. Oxygen prevented glucose uptake (75% inhibition), reflecting possible active sulfhydryl centers (above) or autooxidation of electron transport components. The results suggest the fumarate reductase-coupled electron transport system of B. succinogenes can generate a proton motive force that is used to energize glucose uptake. Na+ and Li+. but not K+, stimulated glucose uptake and may partly account for the growth requirement of B. succinogenes for Na+. However, the data were insufficient to conclude that glucose uptake occurs by a Na+ symport mechanism. Spheroplasts of B. succinogenes transported glucose as well as whole cells, indicating glucose uptake is not dependent on a periplasmic glucose binding protein. A variety of sugars including the nonmetabolizable analog, [inversely proportional symbol]-methylglucoside. did not inhibit glucose uptake. Only cellobiose and 2-deoxyglucose were active and neither behaved as a competitive inhibitor. Metabolism of both sugars was probably responsible for the inhibition. Cellobiose-grcwn B. succinogenes showed a reduced ability to transport glucose compared to glucose-grown cells. This may indicate regulation of synthesis of the glucose carrier protein by cellobiose through a mechanism other than catabolite repression. Differences in the ability to transport glucose were detected between transition cells (transition from lag to log phase of growth) and log-phase cells. However, the differences were not due to different glucose transport mechanisms. Alterations in the structural integrity of the cell envelope, as reflected by osmotic- and cold-sensitivity features of transition and log cells, may have affected the glucose uptake abilities in these cell types.Item Redistribution and fate of applied ¹⁵N-enriched urea under irrigated continuous corn production(North Dakota State University, 1996) Schindler, Frank VincentUnderstanding the redistribution and fate of N is essential for justification of Best Management Practices (BMP). This project was conducted on a Hecla fine sandy loam (sandy, mixed, Aquic Haploboroll) soil at the BMP field site near Oakes, North Dakota. One objective of this investigation was to evaluate the residence times of N03- -N in 20 undisturbed lysimeters and its infiltration time through the soil profile to tile drains. Corn (Zea mays L.) was fertilized with 135 kg N ha -1 as ¹⁵N-enriched urea plus 13.5 and 48.1 kg N ha -1 preplant for 1993 and 1994, respectively. Urea-N was band applied to 20 and 10 undisturbed lysimeters at 2.0 and 5.93 atom percent (at %) ¹⁵N in 1993 and 1994, respectively. Average resident times of N03- -N in the lysimeters was 11.7 months. Lysimeter and tile drainage indicate the presence of preferential pathways. Residence times of N03- -N depend on frequency and intensity of precipitation events. Another objective was to determine what portion of the total N in the crop was from applied urea-N and what portion was from the native soil-N. Nitrogen plots received ¹⁵N enrichments of 4.25 and 5.93 at % ¹⁵N in 1993 and 1994, respectively. At the end of the 1993 and 1994 growing season, 41.5% and 35.7% of the labeled fertilizer N remained in the soil profile, while the total recovery of applied ¹⁵N in the soil-plant system was 86.2% and 75.4%, respectively. Low recoveries of applied N may have been the result of soil or aboveground plant biomass volatilization, or denitrification or preferential flow processes. Further research needs to be conducted with strict accountability of gaseous loss and the mechanism(s) responsible.Item An Analysis of the Arguments Used in the Home School Issue(North Dakota State University, 1988) Meyer, Jaime Paul"An Analysis of the Arguments Used in the Home School Issue," by Jaime P. Meyer is a study employing a twelve point method of analysis taken from the work of Ch. Perselman and L. Olbrechts-Tyteca. This study sought to answer the question: Are the values in the arguments of those for or against conditional home schooling in North Dakota consistent with the values underlying the laws of the state? Chapter I established the nature of the study. Chapter II provided a review of the literature concerning home schooling in North Dakota. Chapter III identified the similarities of the values in the arguments stated by those for conditional home schooling and the laws of the state. Chapter IV noted the dissimilarities of the values in the arguments stated by those against conditional home schooling and the laws of the state. Chapter V concluded that the values in the arguments of those for conditional home schooling are more consistent with the values underlying the laws of North Dakota than the values in the arguments of those against conditional home schooling.Item Pathogenic Variation, Host Specialization and Aggressiveness in Helminthosporium Sativum(North Dakota State University, 1984) El-Nashaar, Hossien MahmoudCommon root rot, caused by Cochliobolus sativus, is an important disease of spring wheat and barley in the northern Great Plains. While the disease has been widely studied, extensive systematic investigation of pathological variation in C. sativus populations has not been reported. Five widely separated North Dakota counties were selected for field sampling. More than 430 isolates of C. sativus were obtained from wheat and barley plants. Pathogenicity of isolates was assessed according to amount of disease on wheat test plants in randomized, replicated greenhouse trials. Data were analyzed using the UNIVARIATE procedure of the SAS computer package. Relative pathogenicities of isolates were normally distributed continuous variables. Although the range of pathogenicity in populations of C. sativus within counties was similar, the means and variances were slightly different. Repeated planting of the same crop often results in an increase of inoculum of soilborne plant pathogens, but little is known of the effect on pathogenicity in the pathogen population. I collected C. sativus from symptomatic wheat plants from a plot planted continuously to wheat for over 90 years and from normally rotated grain fields in the surrounding area. Relative pathogenicity of isolates was tested in replicated greenhouse trials using wheat plants scored for disease six weeks after inoculation. Isolates from the continuous wheat plot were more pathogenic on average than isolates from commercial fields. Long term continuous cropping to wheat appears to shift the population of C. sativus toward more aggressive types, although many less pathogenic types also remain. Variability in C. sativus has been recognized in morphology of culture and pathogenicity for many years. Variability on virulence and/or aggressiveness of C. sativus isolates is not well documented. From the original collection of 432 isolates, 50 were selected to cover the entire range of pathogenicity. In three experiments, relative pathogenicity of the isolates was evaluated according to the amount of disease on each of four durum wheat cultivars. Aggressiveness patterns in the C. sativus-wheat system were reasonably reproducible. The C. sativus isolates originally selected for differential responses to wheat cultivars were not consistent in repeated testing. It was concluded that a range of pathogenicity (= aggressiveness ) exists in the C. sativus population and the apparent host differential responses are not repeatable and are probably experimental artifacts.Item Women's Power: A Cross-Generational Exploration of One German-Russian Farm Family(North Dakota State University, 1992) Dockter, Shona AnnExploration of the familial power women possess is growing as sociologists and anthropologists recognize the legitimacy of power internal to the family. The focus of this research was to uncover the forms of power German-Russian women held as they operated in the private sphere of the family. Attention also focused on the transference of women's power, and the family power dynamics unique to farm families. Members of three generations of one German-Russian farm family were interviewed. The results indicated German-Russian women operated from bases of power derived from their roles as farm wives who contributed to family sustenance, and as caretakers and kinkeepers, maintaining family cohesion. While male power is largely public and formal, women's reliance on the bonds of familial relationships across generations lend them greater power in that realm.Item Scanning Electron Microscope Examination of Sugarbeet Flowers and Fruits Infected with Phoma Betae(North Dakota State University, 1980) El-Nashaar, Hossien MahmoudThere are three natural openings in a mature sugarbeet fruit which serve as avenues of entry for microorganisms: 1) the basal pore which contains dried parenchyma and vascular tissue and is the point where the flower was connected to the stalk; 2) the apical pore where the style was inserted; and 3) the peripheral zone of dehiscence where the operculum separates from the fruit cavity wall during germination. The apical pore was first described in this study. Scanning electron microscopy of the naturally infected fruits showed, for the first time, hyphal penetration through both the basal pore and the peripheral zone. Examination of sugarbeet flowers artificially infected with Phoma betae also showed fungal penetration through the apical pore. Dense hyphal growth was associated with stigmal lobes and ungerminated pollen grains. Fungal growth apparently was stimulated by excretions from the stigma. Penetration of the fruit cavity wall and the operculum would render the fungus inaccessible to protectant fungicides and explains why the most successful seed treatments for P. betae have included volatile mercury fungicides or seed soak in thiram. Such treatment allows direct contact between the toxin and the pathogen.