Microbiology Commons^™

Characterization Of Bacterial Endophytes Isolated From Brassica Carinata And Their Potential Use To Decrease Nutrient Requirements In Crops, Alex Soupir

Electronic Theses and Dissertations

Bacterial endophytes have the capability to enhance plant growth by producing plant growth hormones, solubilizing phosphates, suppressing pathogenic fungi, and reducing plant stress hormones. These capabilities make them desirable limiting the amount of nutrients and pesticides that are applied to crops. Through these assays and isolations, it is possible to identify novel bacterial species. In-vitro testing had shown 9 of the 20 isolates possess the ability to produce indole-3-acetic acid (IAA) with Pantoea agglomerans BC09 producing a concentration of 30.2 ng/μl over 4 days. BC09, Bacillus subilis BC10, and Pantoea sp. BC12 were able to solubilize calcium phosphate, 7 endophytes …

Molecular Facet Of Host-Pathogen Interactions In Fusarium Head Blight In Wheat ( Triticum Aestivum L.), Bimal Paudel

Electronic Theses and Dissertations

Fusarium head blight (FHB) is a severe disease of wheat (Triticum aestivum L.). It not only reduces the quantity of the harvested grains but also decreases the grain quality due to mycotoxins contamination, especially Deoxynivalenol (DON). Qfhb1 (or simply called Fhb1) is the most important quantitative trait locus (QTL) for FHB resistance. Our lab has previously identified wheat gene WFhb1-1 (aka. Wfhb1_c1) as a candidate for FHB resistance gene. Here we report that WFhb1-1 has been cloned. The gene (GenBank # KU304333.1) consists of a single exon, encoding a putative membrane protein of 127 amino acids. WFhb1-1 protein produced in …

The Biology Of The Influenza D Virus, Jieshi Yu

Electronic Theses and Dissertations

Influenza D virus (IDV) was first identified in 2011 from clinically ill pigs in America. In nearly a decade since its discovery, the virus has been detected in multiple animal species in a vast region of the globe and is considered an important cause of concern to animal and human health. IDV utilizes cattle as the primary reservoir. The viral infection can cause mild respiratory disease in cattle and has been indicated as a causative agent of bovine respiratory disease (BRD) complex that is the most common and costly disease affecting the cattle industry. Moreover, outbreaks of IDV in swine …

The Role And Molecular Mechanisms Of Wss1 In Preserving Genomic Stability, Daniel Kwesi Sam

Electronic Theses and Dissertations

Cells are constantly under threat from both exogenous and endogenous sources of DNA damage. Eukaryotic organisms, however, possess conserved mechanisms that accurately and faithfully respond to DNA damage. The inability to effectively remove DNA lesions can lead to an accumulation of mutations which can compromise cellular viability. The DNA damage response is conserved from bacteria to eukaryotic organisms and have been well characterized, however, how covalently crosslinked proteins are removed from DNA remains enigmatic This thesis provides genetic and biochemical evidence implicating Wss1, a yeast metalloprotease in genome maintenance. We have identified SUMOylation to be an important signal that mediates …

Genetic And Biochemical Analysis Of A Conserved, Multi-Gene System Regulation Spore-Associated Proteins In Streptomyces Coelicolor, Joseph Sallmen

Electronic Theses and Dissertations

Streptomyces coelicolor is a Gram positive, filamentous soil dwelling bacterium that exhibits a complex life cycle including the transition from a vegetative mycelium to a sporulating, aerial mycelium. Early genetic studies identified two classes of genes that resulted in developmental blocks, bald and white. The bald (bld) phenotype occurs when colonies cannot produce aerial hyphae. White (whi) colonies exhibit incomplete sporulation and/or loss of production of the concurrently produced grey pigment. While some of the original mutants have been explored, the developmental functions of many of the identified genes are not well understood. Of particular interest …

Genetic Analysis Of A Novel Ftsk Homolog, Hfka, In Streptomyces Coelicolor Development-Associated Chromosome Segregation, Sumedha Sethi

Electronic Theses and Dissertations

A quintessential phenomenon occurring during prokaryotic development is accurate segregation of the replicated genomes into the daughter cells. Key energy-dependent processes like chromosome condensation and subcellular partitioning of the genomes are driven by conserved proteins like SMC, ParB, FtsK. During its complex developmental cycle, Streptomyces coelicolor segregates its genomes into chains of unicellular spores when its multigenomic syncytial aerial hyphae undergo division.

A novel ftsK-like gene, hfkA (Homolog of FtsK protein A), was examined for function and localization during development-associated chromosome segregation. Individual deletions did not affect segregation, but a ΔhfkA ΔftsK mutant exhibited 8% anucleate …

Role Of Topoisomerase Ii Alpha In Dna Topology And T Cell Responses During Chronic Viral Infections, Stella Chinyere Ogbu

Electronic Theses and Dissertations

The clearance of viruses is largely dependent upon the activation of T cells to generate a robust immune response. However, host responses are suppressed during chronic viral infections. In this thesis, we explored the role of Top2α in DNA topology in individuals with chronic HBV, HCV, and HIV infections. We found that Top2α protein expression and activity were low in T cells derived from chronically virus-infected individuals compared to healthy subjects. Using CD4⁺ T cells treated with Top2α inhibitor or poisoner as a model, we demonstrated that Top2α inhibition disrupts the DNA topology, suppresses DNA repair kinase (ATM), and …

A Possible Luxr Solo Type Regulator Of An Antibiotic-Like Compound From The Soil Bacterium Rhodococcus, Katelyn Sellick

Electronic Theses and Dissertations

Rhodococcus, a species of bacteria commonly found in the soil, is an under-explored producer of small bioactive compounds including siderophores, pigments and antibiotics. MTM3W5.2 is a strain of Rhodococcus that was previously discovered to produce an antibiotic-like compound that has inhibitory effects on other Rhodococcus strains, including the veterinary pathogen, R. equi. The biosynthetic gene cluster responsible for production of the antibiotic has been identified, and a small gene, BTZ20_3964 at the start of the operon is believed to be a luxR solo regulator of the gene cluster. The goal of this project was to determine this gene’s …

The Effects Of Constructed Wetlands On Metal Solubilization And Bioavailability In Passive Mine Remediation, Elizabeth Cochran

Electronic Theses and Dissertations

The legacy of coal mining in Appalachia has left many watersheds impacted by abandoned mine drainage. The drainage degrades streams, groundwater and habitats with acidity and toxic heavy metals. The Lowber Passive Remediation System has been in operation since 2004 to remediate high amounts of dissolved Fe, SO₄, Al, and Mn. The site consists of six settling ponds and an extensive wetlands at the finish. This study investigated the resolubilization of Fe and Mn in the wetlands and the role of bacteria in resolubilization. During three seasons, field measurements of water quality and lab analysis of Fe, Mn, …

Effects Of Temperature On Microbial Parameters Associated With Decaying Plant Litter In A Stream Microcosm Experiment, Hunter David Pates

Electronic Theses and Dissertations

Increases in mean surface air temperature under climate-change predictions are expected to affect microbial activity, as well as carbon dynamics in aquatic ecosystems. I explored responses of litter-associated decomposers along temperature ranges typical of temperate streams in laboratory microcosms simulating stream conditions. The objectives of this study were to determine (1) whether the effects of temperature on stream leaf-associated microorganisms can be explained by the Metabolic Theory of Ecology (MTE); (2) if the effects of temperature are the same across temperatures commonly found in temperate streams; and (3) if there are differences in the magnitude of responses to temperature among …

The Q Rule In Bacteriodetes And The Identification And Characterization Of Porphyromonas Gingivalis Glutaminyl Cyclase., John Andrew Houston

Electronic Theses and Dissertations

Background: Porphyromonas gingivalis, a major pathogen associated with chronic periodontitis, secretes variety of proteins, majority of which begins with glutamine. Several of these proteins were found with pyroglutamate (pGlu) at N-terminus suggesting the presence of this posttranslational modification pathway in P.gingivalis. The observation that N-terminal glutamine is over-represented as the first amino acid after signal peptide cleavage, and subsequent confirmation of pGlu formation on the nascent protein via mass spectrometry, led us to conclude that an enzyme must be present as the executor of this reaction. Hypothesis: PG2157 is a glutaminyl cyclase and is responsible for the cyclization of …

Assessing Listeria Risk During Different Stages Of Ice Cream Manufacturing And Storage, Neha Singh

Electronic Theses and Dissertations

Listeriosis is a life-threatening infection caused by foods contaminated with Listeria monocytogenes. Some of the major ice cream recalls in recent years reaffirm the ability of this food-borne pathogen to survive in diverse dairy processing environments and cause cross contamination. Inspection reports revealed certain lapses in implementing adequate hygienic practices for Listeria persistence in the processing environment, leading to cross contamination of ice cream. The higher levels of cross contamination of raw ice cream mix might result in random heat-injured cells when exposed to minimum heat treatment (69°C for 30 min). Evidence about the presence of injured cells in ice …

Isolation And Identification Of Potential Bioinoculants Based On Phosphate Solubilizing And Plant Growth Promoting Benefits, Rachel Raths

Electronic Theses and Dissertations

Conservative models have shown that as populations rise, food production needs to double by 2050. Population increase and the green revolution have caused fertilizer inputs to increase since the 1960’s, increasing environmental issues and production costs. These intensive practices have led to degraded arable land and there has been an increase in urbanization meaning we need to make best use of the farming land that is available and ensure it is sustainable for future food production. Due to this, there has been a higher demand for research on more environmentally and economically friendly approaches to food production. Plant growth promoting …

Shrimp Production Environment And The Gut Microbiome: Effects Of Aquaculture Practices And Selective Breeding On The Gut Microbiome Of Pacific Whiteleg Shrimp, Litopenaeus Vannamei, Angela Landsman

Electronic Theses and Dissertations

Knowledge of the functional role of the gut microbiome in animal health and nutrition may provide solutions to shrimp aquaculture challenges, such as improving disease resistance and optimizing growth particularly with low cost feeds. Successful manipulation of bacteria found in the gut requires a deeper understanding of shrimp microbial communities and how their compositional structure is influenced by environmental conditions, and inherent host factors such as genetics. The initial research investigated the intestinal bacterial communities of the Pacific whiteleg shrimp (Litopenaeus vannamei) reared in pond systems compared to indoor aquaculture facilities as an exploration of the effects of aquaculture practices …

Comparing Gut Microbiome And Virome In The Breast Milk- And Formula-Fed Late Preterm Infants, Zyi Wang

Electronic Theses and Dissertations

The neonatal intestinal microbiome consists of all microorganisms in the gut. Although the microbiome is critical to human health and disease, its colonization remains incompletely understood, particularly in the preterm infant. We aimed to characterize the intestinal bacteria microbiome and virome in moderate-to-late preterm infants. We hypothesized that the bacteria microbiome and virome differs between breast milk and formula-fed infants. We collected stool samples from twenty infants born between 32 0/7 and 36 6/7 weeks gestation. Samples were collected after infants reached full volume enteral feedings. Ten infants were breast milk fed and ten received infant formula. DNA and RNA …

The Effect Of Proteolytic Queues On Antibiotic Tolerance And Persistence Cells Population In Escherichia Coli, Alawiah Abualrahi

Electronic Theses and Dissertations

A major contributing factor to the abundance of antibiotic-resistant microorganisms and failed antibiotic treatment is survival due to antibiotic tolerance and persistence. Antibiotic tolerance is a widespread phenomenon that enables cells to survive treatment without carrying a resistance gene. This phenomenon renders antibiotic treatments less effective and facilitates antibiotic resistance. We are particularly interested in proteases, responsible for degradation of proteins, because of their known relationship to tolerance and persistence. Here, we examine the effects of proteases and antibiotic survival using queueing theory, in which one type of customer competes for processing by servers, that has traditionally been applied to …

Development And Evaluation Of Vaccine Candidates For Senecavirus A, Bishwas Sharma

Electronic Theses and Dissertations

Senecavirus A (SVA) has been associated with several outbreaks of vesicular disease (VD) since 2014 in major swine-producing countries around the world. The virus causes VD that is clinically indistinguishable from foot-and-mouth disease (FMD) in pigs. Currently there are no commercial vaccines available for SVA. Here, we developed a live attenuated SVA strain by mutating a wild type SVA strain SD15-26 (wt SVA). The live attenuated virus, rSVA mSacII, replicated less efficiently in cell cultures in vitro and expressed lower amounts of VP1 and VP2 capsid proteins than wt SVA. Most importantly, the rSVA mSacII virus failed to induce clinical …

Bovine Cellular And Innate Immune Response To Hemostatic Polysaccharides, Brian Kobylkevich

Electronic Theses and Dissertations

Chronic wounds are longstanding dermal wounds that do not heal in a normal amount of time and can commonly last for over a year. These wounds plague humans and farm animals alike. Wounds are characterized by chronic inflammation and are often painful, difficult to heal, have a high recurrence rate, and are potentially debilitating. Long term wounds that do not fully heal are distressing for both humans and animals, but understandably more resources have been directed towards humans. Some treatment options for humans may be suitable for adaptation into the field of animal care. Chronic lesions such as bovine digital …

Hydrodynamic Cavitation As In-Line Process To Control Common Dairy Sporeformers, Pratibha Chaudhary

Electronic Theses and Dissertations

Sporeforming bacteria and their endospores have the ability to survive thermal treatments and proliferate in the milk and dairy products to cause spoilages. We applied the effect of hydrodynamic cavitation in controlling these bacteria and their spores at pilot scale level. Our aim was to investigate a technology that would improve the microbial quality of milk and dairy products, and is capable of being scaled up to be adapted at industrial level. Cavitation damages the cell walls of the bacteria and their endospores (releasing dipicolinic acid, responsible for endospore resistance to extreme conditions), thereby making them susceptible to thermal treatments …

Interactions Of Arbuscular Mychorrhizal Fungi And Bacterial Endophytes On Disease Resistance Of Common Root Pathogens In Wheat, Janice L. Eibensteiner

Electronic Theses and Dissertations

Arbuscular mycorrhiza, a symbiosis between plants and fungi, help plants to capture nutrients such as phosphorus (P), nitrogen (N) and other micronutrients from the aggre in exchange for up to 20% of the fixed carbon (C) from the plant. In addition, arbuscular mycorrhizal (AM) fungi can improve the resistance against abiotic (drought, salinity), and also biotic (pathogen) stresses. Bacterial endophytes promote plant growth and yield by fixing N2 from the atmosphere, assimilating N and transfer it to the plant. Bacterial endophytes can also solubilize phosphate and stimulate plant defense responses, suppressing pathogens. The host plant provides sucrose and a favorable …

Development Of Computational Techniques For Identification Of Regulatory Dna Motif, Cankun Wang

Electronic Theses and Dissertations

Identifying precise transcription factor binding sites (TFBS) or regulatory DNA motif (motif) plays a fundamental role in researching transcriptional regulatory mechanism in cells and helping construct regulatory networks for biological investigation. Chromatin immunoprecipitation combined with sequencing (ChIP-seq) and lambda exonuclease digestion followed by high-throughput sequencing (ChIP-exo) enables researchers to identify TFBS on a genome-scale with improved resolution. Several algorithms have been developed to perform motif identification, employing widely different methods and often giving divergent results. In addition, these existing methods still suffer from prediction accuracy. Thesis focuses on the development of improved regulatory DNA motif identification techniques. We designed an …

Increasing Accumulation Of Glyceollins In Soybeans Via Optimization Of The Fungal Incubation Process, Stephanie Wootton

Electronic Theses and Dissertations

Continual use of antibiotics in the feed of food animals was viewed a solution to the problem of disease outbreaks in livestock produced in confinement operations. This practice also improved animal performance, likely due to the reduction in sub-clinical infections. Unfortunately, this practice led to a new problem, the development of antibiotic resistant microbes. This increase in antibiotic resistance reduced the direct benefits of antibiotics in animal production. Moreover, as antibiotic resistance spread from animal to human pathogens, this practice created a major public health concern. This led the FDA to enact the Veterinary Feed Directive in 2017 that greatly …

Improvement Of Dried Distillers’ Grains With Solubles Utilizing Pretreatments And Fungal Fermentation, Burgandy Zschetzsche

Electronic Theses and Dissertations

Limited inclusion of distillers’ grains in animal feed is primarily due to low protein and high fiber content. Other elements, such as phytate phosphorus levels in DDGS are still an issue for monogastric animals such as swine, poultry, and fish. Furthermore, unabsorbed phytic acid in manure poses a high risk for environmental pollution, because bacteria can hydrolyze phytic acid into free phosphorus that can result in algal blooms and eutrophication of surface or ground water. The objective of this thesis was to improve the nutritional value of corn dried distillers’ grains with solubles (DDGS). This was done utilizing submerged fungal …

Bacterioplankton Biogeography Of The Mississippi River Basin, Jason Taylor Payne

Electronic Theses and Dissertations

Bacterioplankton are important structural and functional components of river networks yet their biogeographical patterns in these systems are largely unknown. Using Illumina sequencing of the 16S rRNA gene we characterized variation in bacterioplankton community alpha diversity (within-sample richness of operational taxonomic units OTUs) and beta diversity (between-sample differences in composition) (1) along a 1 300-km downstream reach of the Mississippi River (2) over a range of temporal scales in the Lower Mississippi River (LMR) and (3) along cross-sectional transects repeated monthly for six months across the LMR floodplain. Particle-associated assemblages were richer in bacterial OTUs and more productive than free-living …

A Bioinfomatic Analysis Of Luminal And Mucosal Ileal Bacteria Colonizing Nursery Pigs Fed Different Protein Sources, Jamie L. Ortman

Electronic Theses and Dissertations

Weaning is a critical time in a young pig’s life that will greatly impact its adult growth and development. The objective of this research was to evaluate the effects of various protein sources on the bacterial composition within luminal and mucosal populations in simple and complex diets to gain a better understanding of factors influencing gut health. Weaned pigs were fed 1 of 3 simple experimental diets: 1) basic diet containing corn and soybean meal (Negative Control - NEG), 2) basic diet + fishmeal (FM; Positive Control - POS), and 3) basic diet + microbially-enhanced soybean meal (MSBM). Phase I …

Modeling Disease Impact Of Vibrio-Phage Interactions, Christopher Botelho

Electronic Theses and Dissertations

Since the work of John Snow, scientists and medical professionals have understood that individuals develop cholera by means of consuming contaminated water. Despite the knowledge of cholera's route of infection, many countries have experienced and still experience endemic cholera. Cholera is caused by the Vibrio cholerae (V. cholerae) bacterium and presents with acute diarrhea and vomiting. If untreated, infected individuals may die due to dehydration. Cholera is a disease that most commonly affects countries with poor infrastructure and water sanitation. Despite efforts to control cholera in such countries, the disease persists. One such example is Haiti which has been experiencing …

Harnessing The Anopheles Microbiome To Conditionally Express Anti-Plasmodial Effectors During The Blood Meal, Jackie Shane

Electronic Theses and Dissertations

The control of vector-borne diseases such as malaria has been an extremely important research subject for hundreds of years. Because of the complex lifecycles of the pathogens that cause these diseases, finding a comprehensive treatment or preventative strategy has proven extremely difficult. Malaria alone is responsible for almost half a million deaths annually, most of them children under 5 years old. This disease is caused by parasitic protists in the genus Plasmodium that are transmitted to humans from Anopheles sp. mosquitoes. Most preventative strategies that are in use today revolve around controlling the vectors, including bed nets, insecticides, and larval …

Virulence Regulation In Pseudomonas Aeruginosa Via The Alginate Regulators, Algu And Algr, The Posttranscriptional Regulator, Rsma, And The Two-Component System, Algz/R, Sean Stacey

Electronic Theses and Dissertations

Pseudomonas aeruginosa is a Gram-negative bacillus able to colonize a wide variety of environments. In the human host, P. aeruginosa can establish an acute infection or persist and create a chronic infection. P. aeruginosa is able to establish a niche and persist in human hosts by using a wide array of virulence factors used for: movement, killing host cells, and evading immune cells and antibiotics. Understanding virulence factors and their regulation has proved to be an important means of combating the morbidity and mortality of P. aeruginosa as well as the ever-increasing threat of drug resistance. By targeting virulence factors …

Synthesis And Characterization Of Targeted Bar Encapsulated Polylactic-Co-Glycolic Acid Nanoparticles To Inhibit Porphyromonas Gingivalis Biofilm Formation., Ranjith Radha Krishnan

Electronic Theses and Dissertations

Periodontal disease is one of the most prevalent infectious diseases worldwide. Between 30-50% of the global adult population suffers from periodontal disease. Some form of periodontitis is present in 46% of American adults, corresponding to annual expenditures in excess of 14 billion dollars for treatment and prevention. Current treatments for periodontal diseases involve mechanical removal of plaque, correction of risk factors, gingival surgery and/or antibiotic therapy. To our knowledge there is no effective therapeutic approach that aims to limit pathogen colonization of the oral biofilm or re-colonization after treatment. Interaction of the pathogen Porphyromonas gingivalis with oral streptococci is critical …

The Role Of Non-Neuronal Acetylcholine In Urogenital Chlamydial Infection, Jessica R. Lockhart

Electronic Theses and Dissertations

Chlamydia trachomatiscauses a bacterial sexually transmitted infection, Chlamydia, that is often chronic and casues reproductive complications in women. We hypothesized that Chlamydia infection increases local acetylcholine (ACh) production, which regulates the host’s inflammatory response to the infection. Female mice infected with C. muridarumwere sacrificed at days 3, 9, 15, and 21 post-infection, genital tract tissues harvested, and immunohistochemistry performed to enumerate ACh-producing cells. Infection increased the number of ACh-producing cells in cervical tissue at days 3,15, and 21 post-infection (pi), uterine tissue at day 3 and 9 pi, and ovarian tissue day 3, 15, and 21 pi. These …