Microbiology Commons^™

Pancreatic Ductal Adenocarcinoma And New Treatments In Development, Melissa J. Moisan

Biology and Microbiology Graduate Students Plan B Research Projects

Pancreatic ductal adenocarcinoma (PDAC) is the most frequently mutated (95%) 5exocrine pancreatic cancers. Patients with PDAC are also the least likely to survive more than 5 years with only 8% overall survivability. The median survival for patients with distant metastasis is less than one year. Most pancreatic ductal adenocarcinoma occurs in the pancreatic head, and the remainder can be found within the body (5% to 15%) or tail (10% to 15%) (14). This extremely aggressive cancer has an increasingly large metastatic dissemination rate to surrounding organs such as the liver, lung, and peritoneum, or can be seen as distant metastases …

Investigating The Impacts Of Ammonium Phosphate-Based Fire Retardants On Cyanobacteria (Anabaena) Growth, Gavin Sutter, Brenda Gonzalez Flores, Grace Laskey, Shane Jurak

Humboldt Journal of Microbiology

In recent years the effects of climate change have taken a devastating toll on ecosystems around the world. With high temperatures and extreme droughts, wildfires have become increasingly common. In order to combat these natural disasters wildland firefighters, drop millions of gallons of fire retardant on public lands and forests. These fire retardants consist of between 80%-100% ammonium phosphate which are incredibly effective as fire suppressants yet is more commonly known for its use in fertilizer. Ammonium phosphate fertilizers can lead to stream eutrophication and undesirable environmental impacts. Our research aims to address the effects of fire retardant on growth …

Essential Oils And Their Antimicrobial Effect On Serratia Marcescens, Seren C. Davies-Hughes, Patricia I. Marquez, Henna N. Schulz, Laura S. Sanchez

Humboldt Journal of Microbiology

S. marcescens is a gram-negative, facultatively anaerobic bacterium that is particularly aggressive in its growing capability. It is a concern in medical fields as well as home environments due to its resistance to most antibiotics, high mortality rate, and easy ability to colonize on soap and other fatty substances. Although testing of natural cleansers such as lemon juice, vinegar, and ammonia has been done on S. marcescens and essential oil efficacy has been tested on Escherichia coli and Staphylococcus aureus, no literature has been published on the effect of essential oils on S. marcescens growth. The purpose of this experiment …

Sex-Dependent Effects Of Induced Acute Inflammation On Glucose Homeostasis And Rna Editing Enzymes, Christian A. Rivas

Graduate Theses/Dissertations

The first line of defense against bodily insults, like pathogen invasion, is the innate immune system. Innate immunity sets in motion countless cascades that result in inflammation. Inflammation simultaneously affects multiple biological processes like metabolism and gene expression. Males and females react differently to inflammation. To understand both molecular and physiological sex differences in inflammation, we examined how inflammation affects gene expression and glucose metabolism. Adenosine deaminase acting on RNA (ADAR1) is upregulated by inflammation and catalyzes RNA editing, a process where nucleotides encoded by the genome are modified. ADAR1 also controls the innate immune reaction by decreasing activity of …

Application Of Nitrate To An Anaerobic Subsurface Bioremediation, Cassie Marie Roberts

Masters Theses

"The highly contaminated subsurface matrix of the Baird and McGuire Superfund site is currently threatening the health and safety of the surrounding environment of Holbrook, MA. Contaminants of significant concern due to high concentration are inorganic arsenite and petroleum hydrocarbons, such as naphthalene. Parsons Corporation and the Massachusetts Department of Environmental Protection have implemented a bioremediation pilot to attempt to degrade the hydrocarbons and arsenic with the application of nitrate. The nitrate would act as an electron acceptor for biodegradation of the hydrocarbon contaminants, produce nitrite that would oxidize reduced iron, and iron oxides would sequester arsenic. Preliminary data showed …

Characterizing The Rhizosphere Microbial Community Of Food Crops In A Changing Climate, Samuel Snider

Theses and Dissertations (Comprehensive)

In recent years, there have been increased occurrences of food-borne illness in Canada, which is not directly associated with animal-related products but is caused by the increasing prevalence of pathogenic outbreaks in fresh produce. This can have health and economic impacts on the agriculture industry in Canada. As such, it is essential to better understand the plant-microbe interactions of crops grown in Canada and determine how climate change may alter the relationship. Plants can promote the growth of beneficial bacteria in the rhizosphere, which can create protective competition between beneficial and pathogenic bacteria. Changes in the environment of the rhizosphere …

Functional Residues Of Cjpata, Robert Lamont

Theses and Dissertations (Comprehensive)

Antibiotic resistance in pathogenic bacteria continues to challenge clinicians and threaten the lives of infected individuals. For this reason, new classes of antibiotics or new targets for antibiotic therapy are needed to circumvent this global health crisis. In Gram-negative bacteria, the enzymes peptidoglycan O-acetyltransferase A and B (PatA and PatB), are responsible for adding acetyl groups to the C-6 hydroxyl group of N-acetyl muramic acid (MurNAc) in peptidoglycan (PG). These acetyl groups are responsible for inhibiting the activity of lysozyme from host organisms that hydrolyze the β1-4 glycosidic linkage between MurNAc and N-acetylglucosamine (GlcNAc). The acetyl groups …

Characterization Of The Clostridioides Difficile Glycosyl Hydrolase Ccsz, Brian Lowrance

Theses and Dissertations (Comprehensive)

Bacteria inhabit many of the harshest environments on Earth; persisting and thriving in conditions thought to be unsuitable for life. One common strategy to withstand these environments is the formation of a biofilm. Biofilm composition varies greatly, depending on the underlying community that produces it. Cellulose, a polymer consistently prevalent in biofilms, has been identified as a virulence factor in many pathogens and is suspected to be involved in pathogenesis by Clostridioides difficile. C. difficile is the #1 cause of hospital acquired diarrhea, which can range from mild to life-threatening infections. Biofilm formation is hypothesized to be involved in …

Identification Of New Substrates From Pseudomonas Aeruginosa Exos, Adam V. Thota

Master's Theses

Pseudomonas aeruginosa is a gram-negative environmental bacterium that uses its intrinsic and acquired antibiotic resistance to infect patients with compromised epithelium, such as cystic fibrosis and burn wounds, and corneal keratitis. In order to cause disease, most strains of P. aeruginosa use the type three secretion system (T3SS) to disrupt cellular signaling and integrity. However, P. aeruginosa may also secrete exotoxins after invading host cells, which prolongs host cell death and maintains an intracellular niche. Of the T3 secreted effector toxins, ExoS, specifically the ADP-ribosyltransferase activity of ExoS, was shown to delay the death of invaded corneal cells, but it …

Investigating Structural And Biochemical Characteristics Of A Peptidase Required For Staphylococcus Aureus Virulence, Sagar Bhusal

Master's Theses

Staphylococcus aureus is an opportunistic Gram-positive pathogen that transiently colonizes 30% of the population at any given time. Upon breaching host skin or mucosal barriers, S. aureus can infect and cause disease in nearly all host tissues. Once inside the host, S. aureus expresses a plethora of virulence factors, mostly regulated by the Accessory Gene Regulatory (Agr) quorum sensing system, which facilitates the evasion of immune responses or directly promotes pathogenesis. The S. aureus Agr system relies on the production of a small peptide known as an auto-inducing peptide (AIP) to control virulence gene expression in response to cell density. …

Investigating Putative Toxin-Immunity Pairs From A New Class Of Rhs Proteins In Pseudomonas Aeruginosa, Syed Faieq Imam

Master's Theses

Pseudomonas aeruginosa is a gram-negative, opportunistic pathogen that is ubiquitous in nature, especially in human/animal impacted environments. One of the reasons for this is the arsenal of protein systems and toxins that P. aeruginosa utilizes to mold its environment to suit its needs. Recently, we discovered a novel locus in the P. aeruginosa genome, which resembles other loci that are known to mediate interbacterial competition. Our bioinformatic analysis found this locus to be enriched in a rearrangement hotspot (rhs) motif which led us to ad-interim term the three ORFs of the loci as rhsB, rhsC, and rhsI. Furthermore, we have …

Multipatch Stochastic Epidemic Model For The Dynamics Of A Tick-Borne Disease, Milliward Maliyoni, Holly D. Gaff, Keshlan S. Govinder, Faraimunashe Chirove

Biological Sciences Faculty Publications

Spatial heterogeneity and migration of hosts and ticks have an impact on the spread, extinction and persistence of tick-borne diseases. In this paper, we investigate the impact of between-patch migration of white-tailed deer and lone star ticks on the dynamics of a tick-borne disease with regard to disease extinction and persistence using a system of Itô stochastic differential equations model. It is shown that the disease-free equilibrium exists and is unique. The general formula for computing the basic reproduction number for all patches is derived. We show that for patches in isolation, the basic reproduction number is equal to the …

Trends In Antibiotic Susceptibility Of Staphylococcus Aureus Isolates In A Pediatric Hospital: An Analysis Of The Impact Of The Sars-Cov-2 Pandemic, Juan Miguel S. Gonzalez Rivero

Honors Undergraduate Theses

Infections caused by the organism Staphylococcus aureus are one of the most common causes for community-associated and healthcare-acquired infections (HAI). Isolates of this bacterium found within the healthcare setting often demonstrate a higher prevalence of antibiotic resistance making these infections difficult to treat. Historically, considerable focus has been placed on methicillin-resistant S. aureus (MRSA), which are strains resistant to β-lactam antibiotics like penicillin, oxacillin and cephalosporins; however, methicillin-sensitive (MSSA) strains may also possess resistance to several first-line antibiotics. Resistance to antibiotics can be acquired through horizontal gene transfer (HGT) by means of mobile genetic elements or by random DNA mutations …

Comparison Of Groundwater Chemistry And Associated Biodiversity Of Sulfidic Karst Habitats In Southcentral Kentucky, Kendall Wheeler

Mahurin Honors College Capstone Experience/Thesis Projects

In most ecosystems, primary production is conducted by plants or photosynthetic microbes; however, extremophilic sulfur-oxidizing bacteria can use hydrogen sulfide gas (H2S) as an electron donor to produce metabolic energy in a type of metabolism called chemoautotrophy. These ecosystems are a prominent feature of some karst landscapes, and two have been observed in the Mammoth Cave system, Sulphur River in Parker Cave and Marianne’s Pass in Mammoth Cave National Park respectively.

Sulfidic water is ubiquitous in southcentral Kentucky and is strongly associated with hydrocarbon deposits. This oil boom of the 1880s in this region predates most environmental regulation and records …

Investigation Of Key Mechanisms Of Contact Dependent Growth Inhibition Systems In Burkholderia Cepacia Complex Species, Zaria K. Elery

Theses and Dissertations--Microbiology, Immunology, and Molecular Genetics

Burkholderia cepacia complex is a group of closely related environmental bacteria that can exacerbate disease in immunocompromised individuals. B. cepacia bacteria are equipped with an arsenal of mechanisms to cooperate and compete for nutrients in various polymicrobial environments. Contact-dependent growth inhibition (CDI) systems are antagonistic mechanisms widespread among proteobacteria. CDI systems consist of Two Partner Secretion pathway proteins that function to deliver the toxic C-terminal portion of the large effector exoprotein (termed ‘BcpA’ in Burkholderia-type CDI systems) to the cytoplasm of a compatible recipient bacterial cell upon direct cell to cell contact. The translocation of BcpA out of the …

Substrate Selection And Effector Gating In The Helicobacter Pylori Cag Type Iv Secretion System, Mackenzie E. Ryan

Theses and Dissertations--Microbiology, Immunology, and Molecular Genetics

Helicobacter pylori is a recognized carcinogen and gastric colonization by strains that harbor the cag type IV secretion system (1) is the strongest known risk factor for stomach malignancy. Gastric adenocarcinoma is the fourth leading cause of cancer-related deaths world-wide ( > 700,000 deaths annually), with H. pylori directly contributing to the development of more than one million new cases of cancer per year accounting for 5.5% of all malignancies. H. pylori exploits cag T4SS activity to alter the mucosal microenvironment by delivering diverse immunostimulatory cargo into target gastric epithelial cells. Currently, the mechanisms by which the cag T4SS …

Receptor Usage And Infection Biology Of Influenza D Virus, Tirth Uprety

Theses and Dissertations--Veterinary Science

Influenza D virus (IDV) utilizes bovines as a primary reservoir with periodical spillover to other hosts. We have previously demonstrated by the traditional hemagglutination assay coupled with sialoglycan microarray and functional assays that IDV can recognize and bind both 9-O-acetylated N-acetylneuraminic acid (Neu5,9Ac₂) and 9-O-acetylated N-glycolylneuraminic acid (Neu5Gc9Ac). Agricultural animals such as cattle can produce both Neu5,9Ac₂ and Neu5Gc9Ac, while humans are genetically unable to synthesize Neu5Gc9Ac. The bifunctional enzyme, glucosamine (UDP-N-acetyl)-2-epimerase/N-acetylmannosamine kinase (GNE) is a master regulator of de-novo sialic acid synthesis while 9-O-Acetylation of sialic acids is catalyzed by …

Location Of The Fibronectin Binding Domain On The Fibronectin Attachment Protein Of Mycobacterium Avium Subsp. Paratuberculosis, Chrissy Rose Hattery

All Graduate Theses, Dissertations, and Other Capstone Projects

Mycobacterium avium paratuberculosis (MAP) is an acid-fast bacillus that causes a fatal granulomatous ileocolitis called Johne’s Disease that affects primarily ruminants. The impact of MAP infection in the US dairy industry is particularly severe, with up to 70.4% of the herds being infected and annual losses as high as $1.5 billion. MAP is capable of persisting for months in the livestock environment and surviving the pasteurization process. While several vaccines are available, none can prevent infection and treatment with antimycobacterial chemotherapy does not result in a cure. Management and control of MAP infection requires characterization of host-pathogen interaction at the …

Novel Amino Acids Dictate Differences In Sivmac239 And Hiv-2 Rod9 Vpx Cellular Localization, Hunter D. Mayhew

All Graduate Theses, Dissertations, and Other Capstone Projects

Vpx is a protein encoded by Human Immunodeficiency Virus Type 2 (HIV-2) and specific Simian Immunodeficiency Viruses (SIVs) that is essential for successful infection of non-dividing myeloid cells. Vpx facilitates viral replication by trafficking the viral genome into the nucleus of infected cells and targeting the primarily nuclear innate immune protein SAMHD1 for proteasomal degradation. Considering that these activities occur at the nucleus, we hypothesized that Vpx nuclear localization would be tightly correlated with these functions. To assess this, site directed mutagenesis in combination with confocal microscopy or Western Blotting analyses were utilized to evaluate the determinants of nuclear accumulation …

Effectiveness Of Atmospheric Cold Plasma In Inactivating Microorganisms, Nadee Shanika Kaluwahandi

Electronic Theses and Dissertations

In the food processing industry, Cold Plasma (CP) is an emerging green process with a number of potential applications. Cold plasma has mostly been used to reduce microbial counts in foodstuffs and biological materials as well as in different levels of packaging, particularly in cases where there is thermal sensitivity. Recent studies have demonstrated that CP technology is being developed for use in the food and agriculture industries. The primary focus is on the interactions between reactive species and food-borne microbes to inactivate them. The literature review discusses both proven and potential applications for cold plasma in food processing, as …