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Articles 1 - 25 of 25
Full-Text Articles in Life Sciences
Analysis Of Spore Shape Determination In Streptomyces, Ning Sun
Analysis Of Spore Shape Determination In Streptomyces, Ning Sun
Electronic Theses and Dissertations
Streptomycetes are Gram-positive, soil-dwelling bacteria that possess a complex life cycle with the alternation of vegetative mycelium, aerial mycelium, and spores. Streptomyces. coelicolor spore maturation is a complex process that involves spore shape metamorphosis from cylindrical pre-spores into ellipsoid spores, but the details of this process have remained enigmatic. Previously, our lab identified a novel gene ssdA that might play a role in spore shape determination using a transposon-based insertion mutagenesis in S. coelicolor. In this study, I isolated a S. coelicolor ssdA-null mutant that showed increased colony hydrophobicity and misshapen spores in sizes and shapes, confirming the …
Retroviral Infection Dynamics In Maine's Wild Turkeys, Stephanie A. Shea
Retroviral Infection Dynamics In Maine's Wild Turkeys, Stephanie A. Shea
Electronic Theses and Dissertations
Widespread wild turkey reintroductions in the late 1900s have led to increases in population density and geographic distribution across North America. This rapid population expansion has put them into proximity with closely-related wild and domestic avian species, increasing the risks of pathogen transmission. Lymphoproliferative disease virus (LPDV) is an avian oncogenic retrovirus detected in wild turkeys in 2009, and previously known to infect domestic turkeys. Following its initial detection, surveys reported variable LPDV prevalence across eastern North America with most wild turkeys being asymptomatic, however diagnostic cases revealed 10% mortality of LPDV-infected individuals. Given its recent detection, little is known …
Determining Effects Of Management Practices On Potato Early Dying And Soil Microbiome And Assessing Risk Of Fungicide Resistance In Verticillium Dahliae, Kedi Li
Electronic Theses and Dissertations
Potato early dying (PED) is a yield-constraining soilborne disease of potato, caused by Verticillium spp. with V. dahliae being the predominant causal agent. Since the pathogen inhabits soil for long periods, PED management aims to reduce the population of V. dahliae in soil. Benzovindiflupyr and azoxystrobin are effective chemicals and frequently used in the control of V. dahliae. In this study, field trials were conducted at Aroostook Farm, Presque Isle, ME in 2019 and 2020. Chemical and biological products have been studied for PED control, and fungicide resistance was also examined. To evaluate fungicide resistance, benzovindiflupyr was characterized on …
Trained Immunity Enhances The Immune Response And Maintains Microbiome Diversity In Aging And Sepsis, P. Spencer Gill
Trained Immunity Enhances The Immune Response And Maintains Microbiome Diversity In Aging And Sepsis, P. Spencer Gill
Electronic Theses and Dissertations
The global population is rapidly aging. It is estimated that over the next thirty years, the number of individuals >60 years of age will increase by over a billion, and the number of individuals over age 80 may increase by 300 million. As humans age, our immune system becomes progressively weaker through a process called immune senescence. This age-related decrease in immune function increases susceptibility to infection and chronic diseases. Sepsis is a leading cause of death worldwide. Over the past two decades, there has been an increased incidence of sepsis which is due, in part, to our aging population …
Genital Chlamydia Infection Is Influenced By The Female Sex Hormones Estrogen And Progesterone In Vivo, Amy Gail Gravitte
Genital Chlamydia Infection Is Influenced By The Female Sex Hormones Estrogen And Progesterone In Vivo, Amy Gail Gravitte
Electronic Theses and Dissertations
Chlamydia is the most common bacterial sexually transmitted infection in the United States and worldwide. It often goes unnoticed due to lack of symptoms and left untreated it can ascend the female genital tract to cause sequelae like pelvic inflammatory disease and irreversible tubal infertility. In reproductive-aged women, female sex hormones estrogen (E2) and progesterone (P4) concentrations fluctuate during the menstrual cycle and are influenced by hormonal contraceptives and hormone replacement therapy. E2 and P4 influence genital Chlamydia infection in women and mice, but these multifactorial interactions are not entirely mapped out. The complex interplay of E2 and P4 with …
Characterizing The Role Of Prophages On Whib7 Expression And Antibiotic Resistance In Mycobacterium Chelonae, Jaycee J. Cushman
Characterizing The Role Of Prophages On Whib7 Expression And Antibiotic Resistance In Mycobacterium Chelonae, Jaycee J. Cushman
Electronic Theses and Dissertations
Mycobacterial pathogens are responsible for an ongoing public health crisis. Mycobacterium abscessus is the causative agent of lung infections that disproportionately affect immunocompromised individuals and is the most intrinsically antibiotic-resistant bacterial species known. These characteristics make M. abscessus infections difficult to treat, with a success rate of only 45%. While some extensively resistant isolates are caused by mutations in drug targets, others appear to be a result of increased intrinsic drug resistance. Common among these strains is the presence of integrated viral genomes (prophage) that are known to contribute to fitness and antibiotic resistance in other pathogens but whose roles …
Understanding The Adhesion Mechanism In Mycelium-Assisted Wood Bonding, Wenjing Sun
Understanding The Adhesion Mechanism In Mycelium-Assisted Wood Bonding, Wenjing Sun
Electronic Theses and Dissertations
The increasing environmental awareness has led to an increased interest in developing more sustainable materials as alternatives to petroleum-derived products. Among different nature-based products, fungal-mycelium-based bio-composites have gained considerable attention in various applications. Multiple materials with different densities and structures and potential applications can be fabricated by inoculating filamentous white-rot fungi in lignocellulosic materials and other substrates. Different from lower-density as-grown foam-like mycelium composites, higher-density mycelium-lignocellulosic panels have the potential to replace commercial particleboard and fiberboard bonded by petroleum-based resins. This kind of composite can be produced by directly adding heat and pressure to the low-density foams or by assembling …
Neuroinflammation, Peripheral Inflammation And Gut Microbiome Profiles In Male Mice From Two Proposed Mouse Models Of Social Behavior Deficits, Sarah Parkinson
Neuroinflammation, Peripheral Inflammation And Gut Microbiome Profiles In Male Mice From Two Proposed Mouse Models Of Social Behavior Deficits, Sarah Parkinson
Electronic Theses and Dissertations
Autism spectrum disorder (ASD) is a neurodevelopmental disorder marked by social deficits and repetitive actions. A communication pathway exists between the brain and gut called the gut-brain axis. It is thought that gut bacteria can secrete signaling molecules, triggering inflammation across the body. These studies attempt to determine if markers are expressed in two mouse models of ASD behaviors, BTBR and a valproic acid model. Immunohistochemistry of ionized calcium binding adaptor molecule 1 from male mouse brain tissue showed no microglial activation in any group. Cytokine analysis did exhibit an increase in interleukin 1 (IL-1) in male adult mice only. …
Deciphering The Perpetual Fight Between Virus And Host: Utilizing Bioinformatics To Elucidate The Host's Genetic Mechanisms That Influence Jc Polyomavirus Infection, Michael P. Wilczek
Deciphering The Perpetual Fight Between Virus And Host: Utilizing Bioinformatics To Elucidate The Host's Genetic Mechanisms That Influence Jc Polyomavirus Infection, Michael P. Wilczek
Electronic Theses and Dissertations
JC polyomavirus (JCPyV) is a human-specific pathogen that infects 50-80% of the population, and can cause a deadly, demyelinating disease, known as progressive multifocal leukoencephalopathy (PML). In most of the population, JCPyV persistently infects the kidneys but during immunosuppression, it can reactivate and spread to the central nervous system (CNS), causing PML. In the CNS, JCPyV targets two cell types, astrocytes, and oligodendrocytes. Due to the hallmark pathology of oligodendrocyte lysis observed in disease, oligodendrocytes were thought to be the main cell type involved during JCPyV infection. However, recent evidence suggests that astrocytes are targeted by the virus and act …
Characterizing The Dormancy And Repair Of A Circumneutral Passive Remediation System Receiving Iron And Sulfate-Rich Amd, Garrett Struble
Characterizing The Dormancy And Repair Of A Circumneutral Passive Remediation System Receiving Iron And Sulfate-Rich Amd, Garrett Struble
Electronic Theses and Dissertations
The Wingfield Pines remediation system is a ~20-acre circumneutral, gravity-fed system constructed in 2009 to passively remediate Fe from an ~2000 gallon/minute effluent. In 2017, a fracture to the system’s underground cavern caused the AMD effluent to bypass the system, flowing directly into Chartiers Creek and leaving the system decommissioned between 2017-2019. Soil slurry and water samples were collected in the weeks prior to the system’s reinstalment in September 2019 through January 2020 in order to determine the effect of the repair on remediation efficiency and microbial community composition. This study acted as the first to describe the temporary decommissioning …
Ecological, Evolutionary, And Molecular Mechanisms Driving Pyocin Diversity In Pseudomonas Aeruginosa., Aubrey A. Mojesky
Ecological, Evolutionary, And Molecular Mechanisms Driving Pyocin Diversity In Pseudomonas Aeruginosa., Aubrey A. Mojesky
Electronic Theses and Dissertations
Bacteriocins are narrow-spectrum antibiotics produced in nearly all lineages of bacteria, meaning that these antimicrobials target closely related individuals. The bacteriocins of Pseudomonas aeruginosa, called pyocins, are highly prevalent and diverse in populations of this species. Laboratory studies have shown that pyocins can function to mediate the outcome of interactions, often allowing for the coexistence of multiple strains, as no one pyocin genotype is competitively superior. Although this has been demonstrated under laboratory conditions, the function of pyocins in natural settings and the ecological, evolutionary, and genetic mechanisms underlying pyocin diversity remains unclear. As such, for my dissertation, I …
Determination Of The Biological Functions Of Undefined Domains Of Veev Nsp2., Andrew Michael Skidmore
Determination Of The Biological Functions Of Undefined Domains Of Veev Nsp2., Andrew Michael Skidmore
Electronic Theses and Dissertations
Alphaviruses are positive sense, single strand, RNA viruses. These viruses occur on every populated continent. Alphaviruses are divided into two clades, the New-World and Old-World viruses. The New-World viruses include Eastern (EEEV), Western (WEEV), and Venezuelan equine encephalitis viruses (VEEV), and cause neuroinvasive disease. The Old-World viruses include Chikungunya (CHIKV) and Ross River viruses (RRV), and typically cause multijoint arthralgia. There are currently no approved antiviral therapeutics or vaccines for any alphavirus, making them a high priority for antiviral drug design and discovery. A benzamidine inhibitor (ML336) of VEEV was characterized, and determined to inhibit replication of VEEV RNA during …
Auxin-Based Herbicide Program And Rhizobia Application For Weed Control And Nodulation Potential In Auxin Tolerant Soybean, Joy Amajioyi
Auxin-Based Herbicide Program And Rhizobia Application For Weed Control And Nodulation Potential In Auxin Tolerant Soybean, Joy Amajioyi
Electronic Theses and Dissertations
Foliar-applied Bradyrhizobia to V4 soybean has been reported to increase yield up to 5%. However, a stand-alone product application may not be practical. Applying with other treatments such as post-emergence herbicide application may be economical but herbicide and/or additives may be deleterious to rhizobial growth. A laboratory study investigated the impact of herbicides (glyphosate and dicamba), additives (an oil to improve absorption and spreading; and AMS used to overcome hard water impacts on glyphosate), and herbicide + additives on bacterial growth. Optical density (OD) measurements at the wavelength of 650 nm assessed solution turbidity, a surrogate measure of bacterial growth. …
Free-Living Diazotrophs And The Nitrogen Cycle In Natural Grassland Revealed By Culture Dependent And Independent Approaches, Amrit Koirala
Free-Living Diazotrophs And The Nitrogen Cycle In Natural Grassland Revealed By Culture Dependent And Independent Approaches, Amrit Koirala
Electronic Theses and Dissertations
Biological nitrogen fixation contributes to half of the global supply of nitrogen to the biosphere. It is carried out by a diverse group of prokaryotes called diazotrophs via the nitrogenase enzyme. Nitrogen fixation research is focused on the narrow group of symbiotic diazotrophs, and the vast majority of free-living diazotrophs which contribute significantly to fixed nitrogen are yet to be explored. The goal of this research was to access phylogeny of diazotrophs considering the most up-to-date genomic information and apply that knowledge to understand the diversity of free-living diazotrophs in a natural grassland ecosystem, both by culture dependent and independent …
Study On The Human Gut Bacteria Under Different Ecological Conditions: Antibiotic Perturbation And Dietary Quercetin, Shruti Shashidharan Menon
Study On The Human Gut Bacteria Under Different Ecological Conditions: Antibiotic Perturbation And Dietary Quercetin, Shruti Shashidharan Menon
Electronic Theses and Dissertations
The human intestine encompasses a vast community of microorganisms known as the gut microbiota that play a crucial role in maintaining health. Common perturbations such as changes in the normal diet, antibiotic treatment, and changes in environmental conditions can alter the gut microbiome. This can create dysbiosis in the gut leading to disease conditions. Therefore, it becomes important to determine the forces that influence the gut microbial ecology. In the first study, we focus on antibiotic perturbations on microbial succession and resilience in a synthetic consortium consisting of the most prevalent gut bacteria in humans. In addition, we investigated the …
Improving Nutritional Properties And Extractability Of Pea Proteins For Human Consumption Via Fungal Bioprocessing, Camille Massmann
Improving Nutritional Properties And Extractability Of Pea Proteins For Human Consumption Via Fungal Bioprocessing, Camille Massmann
Electronic Theses and Dissertations
Yellow peas are a rich source of protein and phytochemicals. Peas are compatible with many diets restricted by sensitivities, allergies, or personal choice. As a result, peas are gaining popularity in food markets, despite the challenges they present. The biggest challenges for pea proteins in food markets are high content of fiber, starch, and saponins. These components cause processing challenges and create undesirable textures and bitter flavors. Pea proteins are typically extracted with alkaline extraction or air classification methods which result in 80% and 50% protein products respectively. With low protein purity, these products are not competitive with other, more …
Characterization Of The Rumen Bacterial Communities Of Bison Heifers Fed A Grass-Based Diet Vs A Grain-Based Free-Choice Diet, Anlly Miley Fresno Rueda
Characterization Of The Rumen Bacterial Communities Of Bison Heifers Fed A Grass-Based Diet Vs A Grain-Based Free-Choice Diet, Anlly Miley Fresno Rueda
Electronic Theses and Dissertations
A century ago, the North American grasslands and prairie ecosystems were dominated by bison. At least 30 million bison roamed the Great Plains when the first explorers arrived. By 1900, there were little over a thousand bison remained in the United States and Canada. Recovery efforts has been made since the 20th century to reestablish the herds and increase the bison population. Today, over 500,000 bison are distributed across North America, with more than 90% of the existing bison population under commercial production. Modern conservation strategies are made via the collaborative efforts of conservationist, producers, and researchers, resulting in increased …
Optimized Microbial Recombinant Production Of Hiv-1 Anti-Envelope Antibody Fragments With Applications To Single Particle Tracking Of Virus Assembly, Merissa Michelle Bruns
Optimized Microbial Recombinant Production Of Hiv-1 Anti-Envelope Antibody Fragments With Applications To Single Particle Tracking Of Virus Assembly, Merissa Michelle Bruns
Electronic Theses and Dissertations
In my findings, I have established a set series of protocols to recombinantly produce, purify and apply various fluorescent probes in vitro for the fluorescent labeling and study of the human immunodeficiency virus type 1 (HIV-1) envelope (Env) protein during HIV viral assembly. There remains insufficient knowledge about the molecular dynamics and interactions of HIV-1 Env protein with its counterpart, Gag, on the inner host cell surface during assembly of a mature virus particle. There also remains an insufficient amount of data for the understanding and clarification of the mechanism of action of a known host cell HIV-1 restriction factor, …
Investigating The Development Of Fecal Bacterial Communities In Growing Dairy Calves, Emily Fowler
Investigating The Development Of Fecal Bacterial Communities In Growing Dairy Calves, Emily Fowler
Electronic Theses and Dissertations
The gut development of young calves is crucial for the producer and the calf's future. Many factors can affect the development of a young calf's gastrointestinal system, and there has been little research into the fecal microbiome development of calves from 0 to 12 weeks of age. To gain further insight into this process, development of the fecal microbiome in 12 dairy calves was investigated. Fecal bacterial composition was determined at four time points (weeks 0, 4, 8 and 12) using the 16S rRNA gene through PCR-amplification of the V1-V3 regions from fecal microbial genomic DNA, followed by Illumina MiSeq …
Describing The Gut Microbiome Of Amblema Plicata, Lauren Lawson
Describing The Gut Microbiome Of Amblema Plicata, Lauren Lawson
Electronic Theses and Dissertations
Freshwater mussels are important for nutrient cycling and ecosystem health, as they filter feed on their surrounding water column. This form of feeding makes these bivalves especially sensitive to conditions in their environment. Gut microbial communities (microbiomes) have been recognized as important to both host organism and ecosystem health; however, how microbiomes are organized and influenced is still unclear. In this study, the gut microbiomes of 58 individuals of the freshwater mussel Amblema plicata were compared across two river basins, five rivers, and nine sites in the southeastern USA. Planctomycetes, Firmicutes, and Cyanobacteria were the most common phyla within all …
Electrical Sensing In Non-Excitable Cells To Promote Galvanotaxis And Tissue Survival, Anyesha Sarkar
Electrical Sensing In Non-Excitable Cells To Promote Galvanotaxis And Tissue Survival, Anyesha Sarkar
Electronic Theses and Dissertations
Weak DC fields have been shown to induce polarity, cell migration and cell proliferation in 2D cultures in vitro. To understand the mechanism by which non-excitable cells sense such weak EFs, we have investigated the mechanism of cathode-directed water flow (electro-osmosis) in the boundary layer of cells by reducing it with neutral, viscous polymers. Our results indicate that low molecular weight polymers decrease cathodal migration and promote anodal migration in a concentration dependent manner. High molecular weight polymers do not affect directionality and can be explained using porosity and hydraulic permeability between the polymers. These results provide the first evidence …
Identification Of Loci Influencing Teosinte Crossing Barrier 1 (Tcb1) Efficacy In Maize By Quantitative Trait Loci (Qtl) Mapping And Genome-Wide Association Study (Gwas), Namrata Maharjan
Electronic Theses and Dissertations
Pollen cross-contamination has been a major problem for maize breeders. Various mechanical methods applied to avoid the contaminations are ineffective. The genetic factors related to maize fertilization can be used to develop an effective method to prevent pollen contamination. Pollen rejection ability controlled by Teosinte crossing barrier 1 (Tcb1) is such a genetic system. Silks possessing dominant Tcb1-s reject pollen possessing the recessive allele (tcb1). Successful fertilization occurs when Tcb1-s pollen falls upon tcb1 silks. The efficacy of dominant Tcb1-s was, however, reduced when repeatedly backcross with maize inbred lines, which suggests that there are modifiers to Tcb1-s. To find …
A Biocontrol Pesticide Derived From Mycovirus-Infected Sclerotinia Sclerotiorum Can Induce Plant Resistance, Connor Pedersen
A Biocontrol Pesticide Derived From Mycovirus-Infected Sclerotinia Sclerotiorum Can Induce Plant Resistance, Connor Pedersen
Electronic Theses and Dissertations
Soybean leaf-associated gemycircularvirus-1 (SlaGemV-1) is a novel mycovirus discovered through the metagenomic sequencing of soybean leaves which is capable of inducing hypovirulence in the highly pathogenic fungus Sclerotinia sclerotiorum. RNASeq analysis techniques were used to determine the transcriptional changes caused by the infection of virus in S. sclerotiorum, as well as the transcriptional changes in Glycine max caused by the colonization of hypovirulent, SlaGemV-1-infected S. sclerotiorum. RNASeq results indicate that viral infection leading to hypovirulence may attenuate expression of genes relating to cell wall synthesis, microtubule formation, and metabolism of steroids and natural antibiotics. Cytochrome P450-related genes, kinesin domain genes, …
Assaying Bacillus Amyloliquefaciens Isolates 1ba And 1d3 For Biosurfactant Production And Utilization Of Petroleum Hydrocarbons And Phenolic Acids, Pavan Kulkarni
Electronic Theses and Dissertations
Several Bacillus amyloliquefaciens isolates obtained from wheat residue have been studied as biological agents to control wheat diseases. Notable traits of isolates 1BA and 1D3 include growth with high salt (10% NaCl), at temperatures up to 50°C and over a wide pH range. BIOLOG Gen III plates were used to study and further characterize Bacillus amyloliquefaciens 1BA and 1D3. Both isolates showed tolerance to high salt concentration supporting previous studies. They also grew in the presence of lithium chloride, potassium tellurite, and sodium bromate. Both isolates grew at pH 5, with almost identical carbon source utilization fingerprints. However, D-serine, quinic …
Exploration Of Host Health Benefits By A Defined Consortium Of Butyrate-Producing Human Gut Bacteria In Gnotobiotic Mouse Model, Linto Antony
Electronic Theses and Dissertations
Aberrant gut microbiota composition is found to be associated with several human diseases such as inflammatory bowel diseases (IBD). Reduction in butyrate producing bacteria is one of the characteristic features of such dysbiotic bacterial community in the gut. Modulation of gut microbiota to bring the dysbiotic state back to normal healthy state is a promising therapeutic strategy to cure several diseases like recurrent Clostridium difficile infection (rCDI) and IBD where traditional therapies using pharmacological substances fails to make a difference. Restoration of butyrate producers is found to be an effective method of such gut microbiota modulation. The potential to produce …