63 results
Search Results
Now showing 1 - 10 of 63
Item Evaluation of a Climate-Sensitive Disease Control Strategy and Investigation of Multi-drug Resistance in Infectious Bacterial Diseases: A US-Africa Experience(North Dakota State University, 2012) Mukiibi, HerbertThis paper presents two research projects that explore avenues of controlling infectious diseases both in Africa and the United States. In Uganda, a retrospective study of Otuboi Sub County patient data to evaluate the impact of Stamp Out Sleeping sickness (SOS) intervention was performed. Polymerase Chain Reaction to detect the conjugatively transferred virulence factors from MDR E. coli to Salmonella was performed in North Dakota. Human African Trypanosomiasis prevalence was significantly reduced at intervention year (2006) compared to the pre-intervention years; 2004 (P = 0.00024) and 2005 (P = 0.000001). Of the 22 screened virulence factor genes, eight genes were PCR detected in MDR E. coli 2077 isolate. Six of the detected genes were found to be received by Salmonella transconjugates. The protective effect of SOS intervention was sustained for only two years (2007 and 2008) post intervention. MDR E.coli 2077 isolate conjugatively transferred its virulence factors to Salmonella strains.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 The Decomposition Ecology and Microbial Forensics of the Postmortem Microbiome(North Dakota State University, 2021) Ewald, Adam PatrickEvery living organism dies and is decomposed into nutrients and by-products. This is lead initially by the normal flora of the newly deceased host. The postmortem microbiome, so-called “necrobiome”, undergoes temporal changes affected by the environment in the carcass. The increased data on the necrobiome is fueled by recent advances in genome sequencing analysis techniques. Metagenome sequencing analyzes temporal changes in a population. Genotypic information elucidates identity, structural, and functional traits across a biome. Initially, the necrobiome is composed of taxa common to the living tissue. As decomposition progresses, new and unique taxa emerge. Those suited for growth in the specific environment become dominant. Alpha diversity, beta diversity, and community traits are used to analyze the necrobiome. The necrobiome has potential for forensic evidence predictions. This review covers the succession of the necrobiome specific to body location, their effect on the decomposing carcass, and potential forensics uses of the necrobiome.Item Lung Mucosal Response to Repeated Inhalational Insults with Immunomodulatory Agents in a Murine Model of Fungal Asthma: Airway Epithelium Takes the Center Stage(North Dakota State University, 2013) Pandey, SumaliAsthma is a debilitating disease of the lungs affecting 235 million people worldwide. Fungus-associated asthma leads to a particularly severe type of disease, and exposure to environmental fungi and their products is unavoidable due to the ubiquitous nature of fungal species. Besides being allergenic, fungi are opportunistic pathogens, and anti-fungal and/or allergic pathways may be modified through repeated inhalation of immunomodulatory agents, affecting the outcome of fungus-induced asthma. Our aim in this project was to investigate the extent to which repeated inhalation of immunomodulatory agents influence the lung mucosal responses in a naïve murine host or in one that had been sensitized to fungal proteins (allergic). The immunomodulatory substances chosen hold relevance to human inhalational exposure, and included live or irradiation-killed Aspergillus fumigatus (a fungi) spores, deoxyxnivalenol (a mycotoxin), and fluticasone propionate (an inhalationally administered corticosteroid, commonly prescribed for allergic asthma). In a naïve host, inhalation of live A. fumigatus spores showed pathological features of fungal asthma. However, in an allergen-sensitized lung, both dead and live A. fumigatus spores established fungal airway disease, albeit to different extents. Next, we tested the effect of deoxynivalenol in an allergic host and found that its repeated inhalation did not affect pulmonary disease pathology, but did lead to a dose- and time- dependent increase in mucosal and systemic total IgA. Finally, we tested the effect of fluticasone propionate, and found that it did not influence the development of fungal airway disease, but did induce dynamic changes in lung physiology and antibody titers. Besides mimicking human inhalational exposures, inhalation ensures direct interaction of the inhaled substances with airway epithelium, which plays an important role in defense against inhaled substances and in asthma pathophysiology. By analyzing various mechanisms involved in murine lung-mucosal response to the inhaled substances, a critical involvement of airway epithelium as an orchestrator of immune responses is highlighted, and this would inform mechanism-based future studies. In conclusion, this project is likely to aid in establishing evidence based standards for fungus-related exposures and in making informed therapeutic decisions for fungus-associated diseases.Item Characterizing Humidity, Sex, and B-Cell Gene Regulation in Fungal Allergic Asthma(North Dakota State University, 2020) Kusick, Emma ClaireAsthma is a debilitating lung disease that affects nearly 300 million people worldwide. Environments with high humidity and subsequent mold exposure often trigger allergic asthma. Sex differences have been reported in the incidence, prevalence, and severity of asthma. B-lymphocytes are recruited in high numbers to the allergic lung in response to the inhalation of Aspergillus fumigatus mold spores (conidia). In this work, we used a mouse model of allergic fungal asthma to assess environmental humidity, sex, and B-lymphocytes in an inhalational model of allergic fungal asthma. Our results showed that animals sensitized in low humidity conditions had no airway hyperresponsiveness (AHR), inflammation, but an increase in IgG3 antibody production. Males weighed more than females, female mice had more fibrosis and produced more IgG3 Ab, but sex showed no impact on low humidity. C19+ B-lymphocytes differentially downregulated multiple genes related to allergic asthma returning the body to homeostasis.Item Gene Expression and Evolution in Escherichia Coli Biofilm(North Dakota State University, 2014) Samanta, PriyankarBiofilms can be defined as a complex aggregation of bacterial communities that involves many gene regulatory mechanisms, as well as evolutionary processes to increase biodiversity. Specific Aim 1 used a gene regulation approach to identity novel targets for the development of biofilm prevention and treatment techniques. The goal was to determine genes that get expressed early in biofilm development (prevention targets) and genes that get expressed late and in the outer layer of the biofilm (treatment targets). Biofilm formation is regulated by numerous regulators, including the two-component osmoregulator system EnvZ/OmpR, the colanic acid activator rcsCDB and the global regulator FlhD/FlhC. In this study, we determined the temporal and spatial expression of flhD, ompR and rcsB in E. coli k-12 AJW678 biofilm, as well as the gene expression of flhD in isogenic ompR and rcsB mutants. Results indicated that flhD was expressed early, and in the outer layer of the mature biofilm. We concluded that FlhD/FlhC would be the first target for novel prevention and treatment technique. One mechanism to increase biodiversity in biofilm is the insertion of transposon elements, which was investigated as Specific Aim 2. Insertion of IS elements into the flhD promoter resulted in increased motility in numerous E. coli K-12 strains has been shown in previous study. In this study, we recovered isolates from biofilm, where IS1 had inserted in the flhD promoter further downstream than in previously described strains. These isolates showed reduced motility. We also wanted to determine the effect of an IS element insertion on regulation of flhD expression by OmpR and RcsB in biofilm. Temporal and spatial gene expression of three different GFP-tagged flhD promoters was measured. The results indicated that IS5 insertion in the flhD promoter at the published hotspot did not have any effect on regulation of flhD expression by OmpR and RcsB in biofilm.Item Investigations in Asthma Heterogeneity: The Roles of Aspergillus Fumigatus-Derived Eicosanoid Synthases and Occupational Exposures to Grain Dusts on the Development of Fungal Allergic Asthma(North Dakota State University, 2013) Sharma, AkshatAllergic asthma is an inflammatory syndrome of the respiratory system which changes the airway wall architecture. Using an aeroallergen, murine model of A. fumigatus-mediated asthma, the two studies herein examine the development of asthma in the contexts of host-allergen interactions via A. fumigatus knock-outs of eicosanoid synthases and occupational exposures to corn and soybean dusts. The lack of difference between control and treatment groups seen in post-methacholine airway responses, goblet cell metaplasia, peribronchial inflammation, and fibrosis in the first study show that fungus-derived eicosanoid synthases are dispensable in the development of fungal allergic asthma. However, the same set of respiratory parameters in the grain dust study reveals an increase in BAL neutrophilia and serum IgE titer. The study also underscores a need for modifications of dust exposure times and of time-points of data analysis. These two studies represent unique perspectives on asthma pathogenesis and emphasize the heterogeneity of the syndrome.Item Inhibition of Fusarium Growth and Trichothecene Accumulation in Grain by Antifungal Compounds from Lactic Acid Bacteria(North Dakota State University, 2013) Zhao, HuiFusarium head blight (FHB) is a widely occurring plant disease, which is caused by fungi in the genus Fusarium. FHB leads to mycotoxin accumulation on grain, which causes food safety risk and economic loss. In addition to chemical treatments, biological strategies, like application of lactic acid bacteria (LAB), could be useful in preventing and/or eradicating mycotoxigenic Fusarium growth and mycotoxin production.After comparision of the anti-Fusarium activities by a microdilution assay against Fusarium graminearum 08/RG/BF/51, Lactobacillus rhamnosus VT1 was found to have the highest anti-Fusarium activity. Response surface methodology (RSM) was employed to optimize the incubation conditions for the production of cell-free Lactobacillus culture supernatant (CFLCS) from the strain. The best combination included 34¨¬C, 55 hours, and shaking at 170 rpm for production of CFLCS from L. rhamnosus VT1. Under these incubation conditions, a 10% cell-free culture of Lactobacillus rhamnosus VT1 inhibited 83.7% of the Fusarium growth on microplate. MIC value of the CFLCS with a 104 conidia /well inoculum concentration is 18%.To identify the mechanisms of anti-Fusarium activity, a stepwise regression, with ¥á to enter = 0.15 and ¥á to remove = 0.15, was performed to analyze the data of the RSM design. It was indicated that pH, total acidity, and 3-phenyllactic acid were the most important factors and could be used to explain 39.2% variation of the anti-Fusarium activity. In addition, proteinaceous compounds might be important due to the possible synergistic effect in the CFLCS. CFLCS applied directly to grain not only prevented Fusarium growth, but also changed mycotoxin accumulation. Fusarium growth was inhibited completely by a 50% concentration (V/V) of the CFLCS applied on rice media after 14 days incubation, and almost no mycotoxins were detected. Concentrations of 15%, 30% and 50% of CFLCS as steeping water inhibited Fusarium growth and mycotoxin accumulation on barley in the malting process. Almost no mycotoxins were detected in the samples treated by 50% CFLCS. However, the germination ability of the barley samples was inhibited. In general, the CFLCS showed potential effective anti-Fusarium activity. However, the strategies of application of the CFLCS on grain should be further investigated.Item Current Status of the Biology, Pathogenesis, and Impacts of Ebola Virus(North Dakota State University, 2021) Alamri, DalalEbola viruses (EV) are single-stranded negative-sense RNA viruses belonging to the Filoviridae family. There are 6 species of Ebola, and four of them can cause Ebola virus disease (EVD) in humans. Ebola viral hemorrhagic fever is one of the deadliest diseases known to infect humans and non-human primates. The primary mode of transmission of Ebola has been identified as direct contact with infected animals, humans and body fluids. The early diagnosis of EVD is difficult because of similarities of the initial disease presentation to influenza-like symptoms such as high fever, myalgia, fatigue, headache, and chills. The most common symptoms that have been reported from previous outbreaks were fever, sore throat, abdominal pain, vomiting, bleeding, diarrhea, and chest pain. Several methods have been used to detect Ebola such as ELISA, conventional RT-PCR, and real-time RT-PCR. Scientists have been working on several therapeutics and vaccines to prevent and treat Ebola.Item The Link Between Gut Microbiota Metabolism and Host Gluconeogenesis by Vasoactive Intestinal Peptide(North Dakota State University, 2022) Dawlaty, RaziaThe gut microbiota (GM) plays a beneficial role in host metabolism. In mammals, the GM ferments dietary fiber into short chain fatty acids (SCFA), like propionate, that improves glucose metabolism. Rats fed a propionate diet increased intestinal gluconeogenic (IGN) gene expression, which was blocked by treatment with the neurotoxin, capsaicin, suggesting a neuronal-dependent mechanism. We hypothesized that the gut neuropeptide, vasoactive intestinal peptide (VIP), links GM derived propionate to IGN expression. We fed VIP deficient mice a 5% propionate chow diet (n=60) for 2 weeks and measured mRNA levels for GN genes by dPCR. Basel intestinal and liver GN mRNA expression was dysregulated by the loss of VIP. GN mRNA levels in liver were differentially altered in males versus females fed a propionate diet in a VIP-dependent manner. We conclude that VIP regulates basal intestinal and hepatic GN mRNA expression and mediates propionate induced GN mRNA changes in liver.