Microbiology Commons^™

The Role Of Sinorhizobium Meliloti Type Ivb Pili Protein On Legume Nodule Morphology And Infection, Alexis Chun

Honors Thesis

The symbiotic relationship between legumes and rhizobial soil bacteria leads to the conversion of nitrogen gas to biologically available forms of nitrogen. A critical step in this interaction is bacterial attachment to the host root. A variety of factors are involved in attachment, such as the Type IV pili (Tfp). In pathogens, Tfpb mediates tight adherence to host cells, promoting colonization, however in symbiotic interactions, the role of Tfpb–encoded by pilA genes–is not well understood. To assess the role of Tfpb pili during symbiosis, Melilotus alba plants were inoculated with wild type Sinorhizobium meliloti or ΔpilA deletion mutants; roots were …

On The Resurrection Of Microbes: An Eco-Christological Approach To The Resurrection, Denys Janiga Osb

Obsculta

This article attempts to bring ecology and Christology into conversation through a transdisciplinary approach. It looks at the pastoral implications of eco-anxiety, resurrection ecology in the field of biotechnology, Church teaching on the Resurrection, and concludes by initiating an interpretation of the resurrection appearances in the Gospel of Luke through the lens of the microbiome.

Exercise Reprograms The Inflammatory Landscape Of Multiple Stem Cell Compartments During Mammalian Aging, Ling Liu, Soochi Kim, Matthew T Buckley, Jaime M Reyes, Jengmin Kang, Lei Tian, Mingqiang Wang, Alexander Lieu, Michelle Mao, Cristina Rodriguez-Mateo, Heather D Ishak, Mira Jeong, Joseph C Wu, Margaret A Goodell, Anne Brunet, Thomas A Rando

Faculty, Staff and Students Publications

Exercise has the ability to rejuvenate stem cells and improve tissue regeneration in aging animals. However, the cellular and molecular changes elicited by exercise have not been systematically studied across a broad range of cell types in stem cell compartments. We subjected young and old mice to aerobic exercise and generated a single-cell transcriptomic atlas of muscle, neural, and hematopoietic stem cells with their niche cells and progeny, complemented by whole transcriptome analysis of single myofibers. We found that exercise ameliorated the upregulation of a number of inflammatory pathways associated with old age and restored aspects of intercellular communication mediated …

Effect Of Temperature On The Microbiome Of A Laboratory Reared Colony Of Haemaphysalis Longicornis Ticks, Brianna Mitchell

Poster Presentations

Honors research poster.

Haemaphysalis longicornis is a species of tick native to eastern Asia, including eastern China, Japan, eastern Russia, and Korea. To date, it has invaded and has now established its existence in Australia, New Zealand, and several of the Pacific Islands. This species of tick has recently been introduced to the United States, having a confirmed sighting in November 2017 on a sheep farm in New Jersey and since establishing populations in 18 states along the east coast and Appalachia. Based on the existing locations of H. longicornis in its native regions, as well as in the United …

Immunomodulatory Effects Of Resolvin D2 In A Model Of Infection, Prem Yugandhar Kadiyam Sundarasivarao

Graduate School of Biomedical Sciences Theses and Dissertations

Dysregulated hyperinflammatory host immune response to underlying bacterial infections is a characteristic of sepsis. In sepsis, bacteria often trigger abnormal hyperinflammatory responses which can cause multiple organ failure and if sustained can lead to an immunosuppressive phase where the host is susceptible to secondary infections caused by opportunistic bacteria like Pseudomonas aeruginosa (P. aeruginosa). In our studies, we used a 2-hit model of cecal ligation and puncture (CLP) followed by P. aeruginosa secondary lung infection to investigate cellular and molecular mechanisms in the beneficial action of resolvin D2 (RvD2). Resolvins of the D-series are a group of fatty acids known …

Investigating The Role Of Cytochrome P450 Enzymes In Triazole Drug Efficacy And Toxicity In Whole Organism Zebrafish Model, Heather Cosh

Honors College Theses

Invasive fungal infections account for nearly 1.5 million deaths a year and therefore are considered one of the leading causes of death worldwide. The first line of therapy towards these infections are antifungal drugs in the triazole class such as voriconazole, posaconazole, itraconazole, and isavuconazole. However, these antifungal drug therapies fail in a large number of patients and can produce toxic side effects, therefore increasing the risk of mortality worldwide. While prior research has demonstrated the efficacy of these drugs in mitigating fungal growth in vitro, it is unclear why these drugs fail to protect patients infected with fungal …

Determining The Effects Of Maternal Adiposity On Preterm Neonatal Microbiome And Short Chain Fatty Acid Profiles, Dalton James, William A. Clark Phd, Kristy L. Thomas

Undergraduate Honors Theses

The gut microbiota and its metabolites have vast impacts on the human digestive system, immune system, and health outcomes. Short chain volatile fatty acids (SCVFAs) present in feces can be representative of the interactions of the microbiota present in the gut. Low microbiota diversity in the human gut is highly associated with obesity and adverse health outcomes. Furthermore, the maternal microbiome has a direct impact on neonatal microbiota through various pathways such as environment, skin flora, breast milk composition, and vaginal secretions. This study is aimed to further understand the associations between various factors (maternal adiposity, gestational time, length of …

The Effects Of Salt And Temperature On Three Methanogen Species: Implications For Mars, Katy Dunlap

Biological Sciences Undergraduate Honors Theses

The question of whether life has ever existed on Mars – either in the past or currently – has been pursued for decades. This debate has been prompted by a variety of discoveries regarding similarities between Mars and Earth and more recently concerns over human extinction. Mars, like Earth, once had large amounts of water, a key ingredient for life. H₂O exists on Mars in various forms now, and it is theorized that there is liquid water beneath the surface as well. Mars also contains salt and is very cold at its surface, pointing researchers towards the idea …

Roles For Mycobacterial Dinb2 In Frameshift And Substitution Mutagenesis, Pierre Dupuy, Shreya Ghosh, Allison Fay, Oyindamola Adefisayo, Richa Gupta, Stewart Shuman, Michael S. Glickman

Publications and Research

Translesion synthesis by translesion polymerases is a conserved mechanism of DNA damage tolerance. In bacteria, DinB enzymes are the widely distributed promutagenic translesion polymerases. The role of DinBs in mycobacterial mutagenesis was unclear until recent studies revealed a role for mycobacterial DinB1 in substitution and frameshift mutagenesis, overlapping with that of translesion polymerase DnaE2. Mycobacterium smegmatis encodes two additional DinBs (DinB2 and DinB3) and Mycobacterium tuberculosis encodes DinB2, but the roles of these polymerases in mycobacterial damage tolerance and mutagenesis is unknown. The biochemical properties of DinB2, including facile utilization of ribonucleotides and 8-oxo- guanine, suggest that DinB2 could be …

Exploring Extreme Viruses With Ken Stedman, Kenneth Stedman

PDXPLORES Podcast

In this episode of PDXPLORES, Ken Stedman, Professor of Biology at Portland State University, discusses his distinguished virology career. From discovering his love of extreme viruses at Max Planck Institute for Biochemistry in Munich, Germany, to heading the Advanced Molecular and Cell Biology Research Laboratory and the eXtreme Virus Lab, Steadman has investigated extreme virus structures, function, genetics, and evolution for more than 25 years. He is the co-founder of the research lab Center for Life in Extreme Environments as well as the Chief Scientific Officer of StoneStable, Inc. Adding to his scientific accomplishments and accolades, Professor Stedman …

Disinfectant Efficacy Against Sars-Cov-2 Surrogates, Bovine Coronavirus And Human Coronavirus Oc43, On Hard And Soft Non-Porous Surfaces, Breanna Kimbrell

All Theses

The novel human coronavirus (HCoV), severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), emerged from Wuhan, China in the latter part of 2019. The rapid spread of SARS-CoV-2 amid the most recent COVID-19 pandemic forced countless foodservice establishments (FSEs) across the United States to close, taking a tremendous toll on the foodservice industry. Although primarily transmitted person-to-person, previous studies indicate that the duration of SARS-CoV-2 survival on different environmental surfaces provides adequate time for secondary transmission to occur. To prevent the further spread of SARS-CoV-2, effective disinfection of surfaces in FSEs is necessary. While disinfectants approved for use against SARS-CoV-2 are …

A Cure For Cmb: Empowering Undergrads With Course-Based Research, Aisling Macaraeg

Senior Honors Projects

The Cell and Molecular Biology Department at the University of Rhode Island has a gap between introductory and advanced laboratory courses offered to undergraduate students. The implementation of a Course-based Undergraduate Research Experience (CURE) catered towards second- and third-year undergraduate students would benefit both students and faculty. A CMB-based CURE would allow for the integration of all four tracks within the CMB major through hands-on laboratory experience and create a low-stakes environment for students to practice independent experimental thinking. Students

will reinforce basic laboratory skills and be exposed to novel concepts that can be further explored in detail through advanced …

Role Of Pseudomonas Aeruginosa Exoenzymes S, T, And Y In The Modulation Of Intrinsic Apoptosis In Pulmonary Microvascular Endothelial Cells, Andrea M. Vavrinek

Honors Theses

P. aeruginosa is the most common cause of ventilator-associated pneumonia in ICU patients. P. aeruginosa uses a type III secretion system to inject exoenzymes S, T, U, and Y into host cells, exhibiting unique effects. Pulmonary microvascular endothelial cells (PMVECs) are used to evaluate cellular changes caused by exoenzymes. ExoY infection of PMVECs leads to cell rounding but does not lead to cell death, unlike ExoS/T. The current study evaluated the exoenzyme-induced modulation of intrinsic apoptosis in endothelial cells. Strain PAK, producing ExoS, T, and Y, was compared to isogenic strains expressing either S, SY, T, TY, Y, or none …

Impacts Of Bacterial Evolution On Host Lethality In Drosophila, Andrew Preston

College of Arts & Sciences Senior Theses

Evolution is the process by which species change their genetic traits, such as the pathogenicity of bacteria, over time in response to changes in their environment. Although the genetic mechanisms underlying many evolutionary processes have been revealed, it is still not well understood how opportunistic pathogens, such as Pseudomonas aeruginosa, become virulent. The overall goal of this thesis is to test the Coincidental Evolution Hypothesis, which proposes that the virulence of opportunistic pathogens evolves coincidentally as a by-product of their interaction with their natural predators. I hypothesized that the virulence of ancestral Pseudomonas aeruginosa changes over time if it co-evolves …

Understanding The Role Of Heterodisulfide Reductase During Nitrogen Fixation By Methanosarcina Acetivorans, Grant Shelnut

Biological Sciences Undergraduate Honors Theses

Methanosarcina acetivorans is a methanogenic archaeon (methanogen) that is important for several processes in our biosphere. A feature of interest within this methanogen is the enzyme nitrogenase which catalyzes the reduction of unusable dinitrogen gas (N₂) into a usable form of nitrogen, ammonia (NH₃). How electrons are transferred within M. acetivorans to nitrogenase during N₂ reduction is unknown. Heterodisulfide reductase (Hdr) is a key enzyme known to reduce the electron carrier protein ferredoxin, which is a direct electron donor to nitrogenase in bacteria. I hypothesized that cytoplasmic HdrA2B2C2 functions in electron transfer to nitrogenase and …

An Ecological Perspective Of American Rodent-Borne Orthohantavirus Surveillance, Nathaniel Mull

Graduate Theses and Dissertations

Orthohantaviruses are a global group of viruses found primarily in rodents, though several viruses have also been found in shrews and moles. Many rodent-borne orthohantaviruses are capable of causing one of several diseases in humans, and the mortality associated with these diseases ranges from < 0.1% - 50% depending on the specific etiological virus. In North and South America, orthohantavirus research was ignited by an outbreak of severe disease in the Four Corners region of the United States in 1993. However, despite the discovery of over 20 orthohantaviruses in the Americas, our understanding of orthohantavirus ecology and virus-host dynamics in this region is still limited, and orthohantavirus surveillance is generally restricted in scope to select regions and small portions of host distributional ranges. In Chapter I, I present a literature review on the current understanding of American rodent-borne orthohantavirus ecology. This review focused on under-studied orthohantaviruses, addressing gaps in knowledge by extrapolating information from well-studied orthohantaviruses, general rodent ecology, and occassionally from Eurasian orthohantavirus-host ecology. There were several key conclusions generated from this review that warrant further research: 1) the large number of putative orthohantaviruses and gaps in orthohantavirus evolution necessitate further surveillance and characterization, 2) orthohantavirus traits differ and are more generalizable based on host taxonomy rather than geography, and 3) orthohantavirus host species are disproportionately found in grasslands and disturbed habitats. In Chapter II, I present a prioritized list of rodent species to target for orthohantavirus surveillance based on predictive modeling using machine learning. Probable orthohantavirus hosts were predicted based on traits of known orthohantavirus hosts using two different types of evidence: RT-PCR and virus isolation. Predicted host distributions were also mapped to identify geographic hotspots to spatially guide future surveillance efforts. In Chapter III, I present a framework for understanding and predicting orthohantavirus traits based on reservoir host phylogeny, as opposed to the traditional geographic dichotomy used to group orthohantaviruses. This framework establishes three distinct orthohantavirus groups: murid-borne orthohantaviruses, arvicoline-borne orthohantaviruses, and non-arvicoline cricetid-borne orthohantaviruses, which differ in several key traits, including the human disease they cause, transmission routes, and virus-host fidelity. In Chapter IV, I compare rodent communities and orthohantavirus prevalence among grassland management regimes. Sites that were periodically burned had high rodent diversity and a high proportion of grassland species. However, rodent seroprevalence for orthohantavirus was also highest in burned sites, representing a trade-off in habitat management outcomes. The high seroprevalence in burned sites is likely due to the robust populations supported by the high quality habitat resulting from prescribed burning. In Chapters V and VI, I describe Ozark virus and Sager Creek virus, two novel orthohantaviruses discovered from specimens collected during Chapter IV. Both chapters report full genome sequences of the respective viruses and compare both nucleotide and protein phylogenies with related orthohantaviruses. Additionally in Chapter VI, I support the genetic analyses with molecular and ecological characterizations, including seasonal fluctuations in host abundance, correlates of prevalence, evidence of virus shedding, and information on host cell susceptibility to Sager Creek virus.

Potency Of Novel Anti-Toxoplasmic Compounds, Matthias Walters

Theses/Capstones/Creative Projects

Toxoplasma gondii, the causative agent of toxoplasmosis, is an intracellular apicomplexan parasite. Toxoplasmosis is often asymptomatic, though, it can be debilitating or fatal to immunocompromised individuals and fetuses, being one of the leading causes of fetal mortality and birth defects. Toxoplasmosis is treated with a synergistic combination of drugs pyrimethamine and sulfadiazine; however, these drugs are only effective against the acute stage of infection, and the pyrimethamine is relatively cytotoxic, damaging bone marrow and causing noxious side effects. Due to these limitations, a safer alternative that targets the chronic stage of infection is needed. In this study, we tested …

Effect Of Temperature On The Microbiome Of A Laboratory-Reared Colony Of Haemaphysalis Longicornis Ticks, Brianna L. Mitchell

Honors Theses

Haemaphysalis longicornis ticks are invasive to the United States with potential to transmit several tick-borne pathogens that are native to the United States. Based on existing locations of H. longicornis in its native regions in Asia, as well as its invasive populations that are established in the United States, several geographic range prediction models have been produced to help understand future range expansion and distribution of this invasive tick in North America. Unfortunately, these models do not all agree and there is uncertainty associated with the potential geographic range expansion of H. longicornis ticks in North America. Climate can affect …

College Of Natural Sciences Newsletter, March - May 2023, College Of Natural Sciences

College of Natural Sciences Newsletters and Reports

Volume 4, Issue 2

Page 1 Dean's Message
Page 2-7 Awards and Recognition
Page 8 March 3rd Corothers Seminar
Page 9 54th Geography Convention
Page 10 Spring 2023 Day of Scholars
Page 11 2023 URSCAD Snaps
Page 12-14 Media Coverage of CNS
Page 15 Open PRAIRIE Data

The Effect Of Different Types Of Plastic And Rubbers Often Found In Healthcare Facilities On The Survival Of Potentially Pathogenic Bacteria, Ashely George

Honors Theses

This study focused on the survival of different species of bacteria on different types of plastics and rubbers found in healthcare facilities. The gram-positive coccus Staphylococcus aureus and the gram negative bacillus Escherichia coli, known to have importance as potential pathogens in healthcare facilities, were tested on two types of plastic (polyurethane and Polyvinyl Chloride (PVC)) and two types of rubbers (latex and nitrile) typically found on reusable healthcare surfaces. Known quantities of bacteria were aseptically placed on disinfected plastic surfaces in triplicate, air-dried, and then incubated at room temperature for 30 minutes, 20 hours, and 40 hours. After incubation, …

The Effect Of Algal Wastewater Treatment Systems On Microbial Communities, Alexis Leach

University Honors Program Senior Projects

In collaboration with the Metropolitan Water Reclamation District of Greater Chicago and Gross-Wen Technologies, I examined the microbial communities in experimental tertiary wastewater treatment systems employing algal phytoremediation. Three algal phytoremediation systems were examined: two vertical conveyor belt systems, known as the 10-foot belt system and the series 4 system, and a third system lacking a converter belt in which planktonic algae grew in a control pond. I used EcoPlates to measure carbon substrate utilization by microorganisms in each system. EcoPlates contain thirty-one different carbon substrates, with a dye that indicates microbial use of each substrate. I conducted a Principal …

Elucidating Mechanisms Involved In Host Microbial-Tumor Interactions, Vidhi Chandra

Dissertations and Theses (Open Access)

Cancer is a rising cause of mortality worldwide. Microbiota is the collection of micro-organisms that live inside our bodies and can impact the host health and disease by interacting with the immune and metabolic systems. The relationship between the microbiota and cancer is complex. Gut and intratumoral microbiota can affect cancer development and progression by influencing patient outcomes and therapy responsiveness in several cancer types. Pancreatic ductal adenocarcinoma (PDAC) is an aggressive cancer surrounded by a highly immuno-suppressive tumor microenvironment (TME) which limits efficacy of most available therapies. The tumoral niche provides a privileged microenvironment for microbial colonization that can …

Oncolytic Virus Immunotherapy: Development And Potential For Cancer Treatment, Olivia Guinness

Honors Scholar Theses

The American Cancer Society estimates that in 2023, 1,958,310 new cancer cases and 609,820 cancer deaths will occur in the United States [16]. A promising therapeutic option that has been supported by recent clinical trials is the use of oncolytic viruses to treat malignant tumors. The mechanism of action of existing treatments, such as chemotherapy, radiotherapy, and surgery, differs from that of oncolytic virus therapy because oncolytic viruses are able to affect cancer cells with specificity, minimizing side effects. When infecting a normal, non-cancerous cell, oncolytic viruses do not replicate, leaving healthy cells unaffected. In tumor cells, oncolytic viruses will …

Gene Expression Changes Linked To Phenylpropanoid-Based Resistance To Fusarium Head Blight Of Wheat, Shiv Singla

Department of Plant Pathology: Dissertations, Theses, and Student Research

Fusarium graminearum is a devastating pathogen of wheat that causes Fusarium head blight (FHB) and contaminates the grain with the mycotoxin deoxynivalenol (DON). Resistance to FHB is quantitative and it is important to identify additional genes conferring resistance against it. The goal of this thesis was to examine if the constitutive expression of two sorghum phenylpropanoid pathway genes, SbCCoAOMT (encoding caffeoyl-CoA O-methyltransferase) and SbC3’H (encoding p-coumarate 3-hydroxylase), in the moderately-susceptible spring wheat CB037 can provide Type-I and Type-II resistance to F. graminearum and determine the underlying mechanisms of the enhanced resistance. The constitutive expression lines (CCoAOMT413, CCoAOMT421, C3H112, …

Antimicrobial Resistance In Eskape Pathogens And Its Effect On Modern Medicine And Treatment, Cameran Runge

Honors Program: Senior Projects (Public)

Abstract

ESKAPE pathogens (Enterococcus faecium, Staphylococcus aureus, Klebsiella

pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa, and Enterobacter

spp.) are seeing a growing resistance to multiple classes of antibiotics. Misuse and overuse of antibiotics have played directly into the resistance observed, and the problem is growing exponentially. Antibiotic resistance is partially due to several intrinsic factors limiting the drug's uptake. These include efflux pumps, increased biofilm production, and reduced cell wall permeability in the resistant bacteria. ESKAPE pathogens also acquire resistance through horizontal gene transfer and plasmids. As antibiotics have become less effective, the bacteria can continue to thrive, leading to a detrimental …

The Stringent Response In Pseudomonas Aeruginosa Influences The Phenotypes Controlled By The Gac/Rsm System, Michael Shawn Hooker

Electronic Theses and Dissertations

Pseudomonas aeruginosa is a ubiquitous, opportunistic pathogen that causes acute and chronic infections. Infection is typically initiated via motile and virulent strains. After exposure to stressors, acute infections make both genotypic and phenotypic switches to a chronic, sessile strain. This is due to intricate regulatory networks directing gene expression in response to stressors. One network, GacA/GacS, has been established to control virulence factors. The stringent response of bacteria is mediated by alarmones produced primarily by RelA which responds to starvation.

To study the effect of the stringent response on the virulence switch. A series of experiments were run in both …

Inhibiting Survival Of Salmonella During Desiccation Through The Use Of Naturally Occurring Signals, Joseph Headrick

Electronic Theses and Dissertations

A rising problem in agriculture is the increase of antibiotic-resistant Salmonella cases associated with chicken eggs, which transmit infection to humans. To counter this, new approaches to combat Salmonella in chickens and desiccated on eggshells are vital in the prevention of human foodborne illness. Disrupting signaling pathways with naturally occurring compounds provides a potential novel avenue for prevention of Salmonella infections, as this would disrupt sensing of these environments and inhibit subsequent optimal gene expression. Starting with signals identified in previous studies, salicylic acid was found to inhibit Salmonella desiccation survival on both eggshells and plastic. To expand upon this, …

The Impact Of The American Association For Thoracic Surgery On National Institutes Of Health Grant Funding For Cardiothoracic Surgeons, J Hunter Mehaffey, Hanjay Wang, Adishesh K Narahari, Simar S Bajaj, Anirudha S Chandrabhatla, Alexander S Krupnick, Frank W Sellke, Todd K Rosengart, Y Joseph Woo

Faculty, Staff and Students Publications

Objectives: The American Association for Thoracic Surgery, through its annual meeting, pilot grant funding, Scientific Affairs and Government Relations Committee activity, and academic development programs (Grant Writing Workshop, Clinical Trials Course, Innovation Summit), has aimed to develop the research careers of cardiothoracic surgeons. We hypothesized that American Association for Thoracic Surgery activities have helped increase National Institutes of Health grants awarded to cardiothoracic surgeons.

Methods: A database of 1869 academic cardiothoracic surgeons in the United States was created in December 2020. National Institutes of Health grant records from 1985 to 2020 were obtained for each surgeon using National Institutes of …

Direct Cardiac Reprogramming: A New Technology For Cardiac Repair, Paige E Brlecic, Clark A Bonham, Todd K Rosengart, Megumi Mathison

Faculty, Staff and Students Publications

Cardiovascular disease is one of the leading causes of morbidity and mortality worldwide, with myocardial infarctions being amongst the deadliest manifestations. Reduced blood flow to the heart can result in the death of cardiac tissue, leaving affected patients susceptible to further complications and recurrent disease. Further, contemporary management typically involves a pharmacopeia to manage the metabolic conditions contributing to atherosclerotic and hypertensive heart disease, rather than regeneration of the damaged myocardium. With modern healthcare extending lifespan, a larger demographic will be at risk for heart disease, driving the need for novel therapeutics that surpass those currently available in efficacy. Transdifferentiation …

Desert Spring Prokaryotes And Benthic Macroinvertebrates: Geological And Ecological Controls, Ariel D. Friel

UNLV Theses, Dissertations, Professional Papers, and Capstones

Desert springs are aquatic oases, being considered among the most diverse and imperiled ecosystems on Earth. Despite the ecological significance and threatened status of desert springs, few studies have surveyed the microorganisms in these systems or their interactions with other community members. The primary goal of this dissertation was to describe the major controls influencing the community ecology of prokaryotic and BMI communities in cold- and moderate-temperature desert springs of the southern hydrographic Great Basin. Chapter 1 provides a broad overview of spring ecosystems and of each chapter included in this dissertation. Chapter 2 documents the first-ever, regional-scale survey of …