Microbiology Commons^™

Green Infrastructure Design Influences Communities Of Urban Soil Bacteria, Jessica Lee Joyner, Jordan Kerwin, Maha Deeb, George Lozefski, Bharath Prithiviraj, Anna Paitseva, John Mclaughin, Peter M. Groffman, Zhongqi Cheng, Theodore R. Muth

Publications and Research

The importance of natural ecosystem processes is often overlooked in urban areas. Green Infrastructure (GI) features have been constructed in urban areas as elements to capture and treat excess urban runoff while providing a range of ancillary benefits, e.g., ecosystem processes mediated by microorganisms that improve air and water quality, in addition to the associations with plant and tree rhizospheres. The objective of this study was to characterize the bacterial community and diversity in engineered soils (Technosols) of five types of GI in New York City; vegetated swales, right of way bioswales (ROWB; including street-side infiltration systems and enhanced tree …

Investigation Of Origin And Growth Of Fungi In Coastal Beach Sand, Ruth L. Wright

Honors Theses

In a previous study from this lab (Stevens, Evans, & Aguirre, 2012) yeast colonies were isolated and grown grown from sand collection at pristine, medium use and high use beaches along the grand strand. In that study greater yeast abundance and greater diversity both correlated with higher census of human use, suggesting that some yeast growth of sites was anthropogenic. However the sand matrix itself also varied from very fine, uniform, dark sand at the pristine beach to coarser, color varying, less tightly packed sand at residential and commercial beaches. This suggested an alternative hypothesis to differential colonization and growth …

See The Forest For The Leaves: Foliar Fungal Community Composition And Volatile Organic Compound Production, Joshua Copeland

Master's Theses

Endophytes are microbes that live within plants without causing detectable illness. These microorganisms can emit volatile organic compounds (VOCs), airborne signaling molecules that can significantly affect plant growth. Despite the prevalence of endophytes and their VOCs, little is known about these factors important to plant health. With this in mind I isolated fungal endophytes from leaves of Populus trichocarpa and Populus fremontii, tree species with economic and environmental uses, to determine if endophyte communities are reserved between the closely related tree species and over seasons. Surface sterilized leaf fragments were plated onto malt extract agar and the resulting fungi were …

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, …

Fungi In A Hot, Dry, Changing World, Miriam I. Hutchinson

Biology ETDs

My doctoral work focused on understanding the reciprocal relationship between fungi and their environment, namely how fungi respond to environmental flux, as well as how fungi can modify and structure their habitats, especially in the context of climate change. As such, I aimed my research on fungi with distinct adaptations to their environmental niches: endophytic fungi that inhabit plant tissue and thermophilic fungi that are capable of growing at the upper temperature limit for eukaryotic life. My research consisted of three studies. First, I investigated the thermophilic species Myceliophthora heterothallica to demonstrate its use as a model organism for efficient …

Warming Up: Climate Change Related Shifts Of Mycorrhizal Fungal Communities In High Latitude Ecosystems, Megan Rae Devan

Biology ETDs

This dissertation examines how climate change affects mycorrhizal fungal communities in boreal and arctic ecosystems. In chapter one, I revealed that increases in fire severity and related increases in deciduous tree dominance result in greater Ascomycota relative abundance (RA) and subsequent declines in Basidiomycota RA. In chapter two I analyzed the effects of post-fire mycorrhizal fungal communites on host growth. There were trends at the fungal genus level that were largely reflected at the guild level across all hosts; however, there were some fungal genera that had the opposite effect on different host species. In chapter three, I found host …

Characterization Of Bacterial Isolates Obtained From Commercial Poultry Feed And Retail Food Using Whole Genome Sequence Analysis And Selected Biochemical Tests, Elena George Olson

Electronic Theses & Dissertations

The goals of this study is two-fold. The first part investigates bacterial isolates from commercial poultry feed and the second part deals with bacterial isolates recovered from retail food. In order to reduce pathogen contamination in poultry products identification of overall microbial populations in poultry production processing steps have always been considered an important monitoring tool for assessing sanitizer effectiveness and the corresponding responses of bacteria load levels on poultry carcasses. Bacterial isolates recovered from corn-based chicken feed were purified on aerobic plate count agar and eleven morphologically different colonies were selected for whole genome sequencing. In this part, the …

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 …

Synthesis And Characterization Of A Long-Acting Emtricitabine Prodrug Nanoformulation, Ibrahim M. Ibrahim

Theses & Dissertations

The introduction of highly active antiretroviral therapy led to a paradigm shift in the management of HIV/AIDS changing a disease considered “a death sentence” to “a manageable chronic disease”. Nevertheless, challenges exist for successful treatment of HIV, including patient adherence to the complex daily regimens and the inability of current formulations to target viral sanctuaries. Introduction of nanoformulated antiretroviral therapy (ART) is a promising alternative to tackle these challenges. Our laboratory has been focusing on developing long-acting (LA) nanoformulated antiretrovirals and has succeeded in developing LA integrase inhibitors. However, challenges for this approach extend to a range of short-acting hydrophilic …

Development Of A Long-Acting Nanoformulation Of Dolutegravir For Prevention And Treatment Of Hiv-1 Infection, Brady Sillman

Theses & Dissertations

Dolutegravir (DTG) is a potent human immunodeficiency virus type 1 (HIV-1) integrase strand-transfer inhibitor (INSTI) with a high barrier to viral drug resistance. However, opportunities to improve its profile abound. These include extending the drug’s apparent half-life, increasing penetrance to “putative” viral reservoirs, and reducing inherent toxicities. These highlight, in part, the need for long-acting, slow effective release antiretroviral therapy (LASER ART) delivery schemes. A long-acting (LA) DTG was made by synthesizing a hydrophobic and lipophilic prodrug encased with poloxamer (P407) surfactant. This modified DTG (MDTG) reduced systemic metabolism and polarity, increased lipophilicity and membrane permeability, improved encapsulation, and formed …

Yfmk Is A Novel Nε-Lysine Acetyltransferase That Directly Acetylates The Histone-Like Protein Hbsu In Bacillus Subtilis, Valerie J. Carabetta, Todd M. Greco, Ileana M. Cristea, David Dubnau

Rowan-Virtua Research Day

Recently, N^e-lysine acetylation was realized to be a prevalent bacterial post-translational modification (PTM), contrary to the historical notion that this was a rare occurrence. Acetylation can impact protein function in multiple ways, by modifying conformation, interactions, subcellular localization or activity. In bacteria, hundreds of proteins are known to be acetylated, including those involved essential processes such as DNA replication, nucleoid organization, translation, cell shape, central carbon metabolism, and even several virulence factors. Despite the growing recognition that numerous proteins are acetylated, the biological significance of the vast majority of these modifications in any bacteria remains largely unknown. Previously, …

Screening Of Crude Microalgal Extracts For Antimicrobial Activity, Patrick Matulich

Theses & Dissertations

Microbial biofilm associated infections are a significant threat to patients with medical devices and are partially responsible for the increased resistance seen in nosocomial infections. The biofilm chemical and physical properties restrict access of chemotherapeutic agents. Therefore, there is a need to enhance the antimicrobial effects of current chemotherapeutic agents. Microalgae live in competitive environments that include film-forming, opportunistic pathogens S. maltophilia and C. albicans. Extracts from 5 diverse species of microalgae were screened for antimicrobial enhancing effects against established biofilms with two different extraction solvents, 3:1 hexanes and isopropyl (HIPA) and 2-methyltetrahydrofuran (2-MTHF).

Three species, B. braunii, …

Isolation, Analysis, And Partial Characterization Of An Inhibitor Of Neisseria Gonorrhoeae, Natania Paul

Undergraduate Honors Theses

There is an emerging threat of Neisseria gonorrhoeae strains that are resistant to all antibiotics. Because of this, the purpose of this research is to isolate, analyze, and partially characterize a new inhibitor(s) of N. gonorrhoeae. Since there is an unknown molecule secreted by Candida albicans that inhibits N. gonorrhoeae, this molecule can be partially characterized using ¹H NMR Spectroscopy to assist in the development of a new antibiotic compound. It was hypothesized that quorum-sensing molecules, trans, trans- farnesol, tyrosol, phenylethyl alcohol, and tryptophol, could be possible candidates for the inhibitor. Because of this, ¹H …

Developing A Modern Microbiology Laboratory Manual To Enhance Student Learning, Alexander Yonchak

Senior Honors Projects

My project has been addressing the issue of incorporating recent developments in biosafety and pedagogical approaches for lab-courses into our existing educational curriculum by developing a new, modern lab manual aimed at improving experiential learning for introductory microbiology teaching labs. Through researching the most recent safety regulations, industry standards, & guidelines for such teaching labs, my manual clearly delineates learning outcomes to match the skills expected of undergraduates completing degrees within the life sciences. In addition, the lab manual that I have designed has been modernized to incorporate the most recent recommended safety precautions and is written in a user-friendly …

The Effect Of Stenotrophomonas Maltophilia On Gram-Negative Cystic Fibrosis Pathogens., Joshua D Stewart

College of Arts & Sciences Senior Theses

Cystic Fibrosis (CF) is the most common lethal genetic disorder in the Caucasian population with an incidence of 1 per 3,000 live births and a median predicted survival of only 47 years. Respiratory failure due to repeated pathological insults to lung tissue by infection is the ultimate cause of mortality in the majority of patients. The lung microenvironment created by CF highly favors colonization by opportunistic pathogens such as Pseudomonas aeruginosa, Stenotrophomonas maltophilia, Burkholderia cenocepacia, and Achromobacter xylosoxidans. Biofilm formation by multiple bacterial species contributes to the chronic, persistent, and difficult to treat nature of CF infections. This study seeks …

Detection, Identification, And Metagenomic Characterization Of Cyanobacteria In Barnegat Bay, New Jersey, Roksana M. Rahman

Seton Hall University Dissertations and Theses (ETDs)

Cyanobacterial harmful algal blooms (CHAB), caused by eutrophication, is known to threaten both wildlife and human health. Barnegat Bay, also home to Oyster Creek nuclear power plant, has experienced an elevated levels of nitrogen due to human activity such as recreational activity and urbanization. This has caused an increase of CHAB’s at a more frequent rate within Barnegat Bay. In order to detect possible CHAB causing cyanobacteria, water samples were collected from 12 different locations within Barnegat Bay. Each sample was filtered through a 30- and 0.4-mm polycarbonate filter sequentially. Chelex DNA extraction, polymerase chain reaction (PCR), and gel electrophoresis …

The Chelation Of Metal Ions By Vicibactin, A Siderophore Produced By Rhizobium Leguminosarum Atcc 14479, Joshua Stinnett

Undergraduate Honors Theses

Vicibactin is a small, high-affinity iron chelator produced by Rhizobium leguminosarum ATCC 14479. Previous work has shown that vicibactin is produced and secreted from the cell to sequester ferric iron from the environment during iron-deplete conditions. This ferric iron is then transported into the cell to be converted into ferrous iron. This study uses UV-Vis spectroscopy as well as ion trap-time of flight mass spectroscopy to determine that vicibactin does form a complex with copper(II) ions, however, at a much lower affinity than for iron(III). Stability tests have shown that the copper(II)-vicibactin complex is stable over time. The results of …

The Importance Of Rnd-Type Efflux Pumps In The Interactions Of Pseudomonas Aeruginosa With 4-Methoxybenzaldehyde, Sanchirmaa Namjilsuren

Honors Theses

Pseudomonas aeruginosa is a common hospital-acquired pathogen and is often associated with high mortality rates due to the development of multidrug-resistance. Antimicrobial plant-derived (phyto-) aldehydes present a promising alternative to antibiotics due to their broad-spectrum antimicrobial activity and low propensity to trigger resistance. However, two main problems preclude the widespread application of these compounds: chemical instability and low antimicrobial efficacy. The ongoing collaboration between the Mavrodi and Patton labs at USM has recently addressed the problem of chemical instability by incorporating plant aldehydes into polymer materials called Pro-Antimicrobial Networks via Degradable Acetals (PANDAs). Thus, this study aimed to address the …

The Impact Of Oxygen On The Intracellular Survival Of Listeria Monocytogenes, Amber N. Coats

Honors Theses

Listeria monocytogenes is an intracellular pathogen that is responsible for the foodborne disease listeriosis. In order to invade host cells and establish an infection, this pathogen must travel through the gastrointestinal tract where it is exposed to a variety of stressors, including low pH, bile, and variations in oxygen concentrations. These stressors necessitate this organism’s ability to sense and respond to its environment. Previous research has shown that bacteria use two-component systems to sense and regulate genes needed for improved survival in stressful environmental conditions. The goal of this study was to determine if the expression of the putative oxygen …

Reporting Charcoal Rot In Chia And Developing A Susceptibility Assay, Reis M. Misaka, Hagop S. Atamian Dr., Julien Besnard Dr.

Student Scholar Symposium Abstracts and Posters

Chia (Salvia Hispanica) cross breeds were planted in the summer of 2018 with the intent of selective breeding for agricultural benefit. Preexisting pathogens in the soil caused 40-50% fatality of adult plants. This was surprising due to the precursory knowledge that chia has antibiotic and antifungal oils (Elshafie et. al. 2018); chia was only recently documented to be susceptible to Fusarium wilt (Fusarium oxysporum). The primary pathogen responsible was identified as Macrophomina phaseolina (aka charcoal rot); a widespread soilborne pathogen which has multiple commercial hosts (Su et. al. 2001).

M. phaesolina on wheat seed vector where used as …

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 …

Challenging The Paradigm Of Clinical Triazole Resistance In Aspergillus Fumigatus, Jeffrey Michael Rybak

Theses and Dissertations (ETD)

Invasive aspergillosis is a leading cause of morbidity and mortality among immunocompromised populations and is predicted to cause more than 200,000 life- threatening infections each year. Aspergillus fumigatus is the most prevalent pathogen isolated from patients with invasive aspergillosis, accounting for more than 60% of all cases. Currently, the only antifungal agents available with consistent activity against A. fumigatus are the mold-active triazoles and amphotericin B, of which the triazoles commonly represent both front-line and salvage therapeutic options. Unfortunately, the treatment of infections caused by A. fumigatus has recently been further complicated by the global emergence of triazole resistance among …

Prevalence Of Aggregatibacter Actinomycetemcomitans And Fusobacterium Nucleatum Among Clinical Orthodontic Saliva Samples, Jason Robert Klingler

UNLV Theses, Dissertations, Professional Papers, and Capstones

Changes to the oral microflora occur when there are shifts in the levels of the numerous bacterial species. Changes in bacterial load occur in health, disease, and dental treatments such as orthodontics and can be detected through saliva. Many studies dealing with saliva have centered around detecting bacteria known for correlation with chronic periodontitis and caries. Fewer have focused on bacterial species that contribute to microbial shifts not strictly correlated with disease. Measuring the degree of disease progression or future susceptibility is not always possible with traditional clinical parameters alone.

Aggregatibacter actinomycetemcomitans (AA) is a bacterial strain that serves as …

Effect Of Common Oxidative Water Treatments On Acanthamoeba Internalized Legionella, James Park

UNLV Theses, Dissertations, Professional Papers, and Capstones

Legionella pneumophila can cause pneumonic and non-pneumonic disease in humans. Infections occur from aerosolized contaminated water. This bacterium is an opportunistic intracellular pathogen able to infect both protozoans, such as Acanthamoeba polyphaga, and human macrophages. Both L. pneumophila and A. polyphaga resist commonly used water treatments, such as chlorination, but L. pneumophila has displayed greater resistance in the presence of A. polyphaga. Therefore, there is concern that L. pneumophila could become established in plumbing systems after water treatment, leading to infections. The objective of this study was to show the effect of chlorine and chlorine dioxide exposures on the survival …

Beyond Genetics: Addressing Activity In Microbial Ecology, Scott Christopher Thomas

UNLV Theses, Dissertations, Professional Papers, and Capstones

The field of microbial ecology is on the cusp of another revolution, one that uses synergy to address the limitations of previous studies. My dissertation is representative of the new era of research to come, through combining the latest technological advances with established classical methods to provide a more complete understanding of microbial ecosystems. In my first study, I evaluate the conservation of central carbon metabolic pathways and activity along a temperature and diversity gradient (60-95 ℃) through the use of 16S rRNA gene amplicon data, metagenome sequencing, and position-specific 13C-labeled metabolite probing. In my second study, I provide the …

Thiol-Based Misfolding: Linking Redox Balance To Cytosolic Proteostasis, Ford Amy

Dissertations and Theses (Open Access)

The eukaryotic cytosolic proteome is vulnerable to changes in proteostatic and redox balance caused by temperature, pH, oxidants and xenobiotics. Cysteine-containing proteins are especially at risk as the thiol side chain is subject to oxidation, adduction and chelation by thiol-reactive compounds. All of these thiol-modifiers have been demonstrated to induce the heat shock response and recruit protein chaperones to sites of presumed protein aggregation in the budding yeast Saccharomyces cerevisiae. However, endogenous targets of thiol stress toxicity responsible for these outcomes are largely unknown. Furthermore, I hypothesize proteins identified as redox-active are prone to misfolding and aggregation by thiol-specific …

Hsp70-Mediated Regulation Of Hsf1 Transcriptional Activity In Saccharomyces Cerevisiae, Sara Peffer

Dissertations and Theses (Open Access)

In eukaryotic cells, protein homeostasis and cellular fitness is promoted by the transcription factor heat shock factor 1 (HSF1) during exposure to proteotoxic stress. HSF1 controls the basal and stress-induced expression of molecular chaperones and other protective targets. Dynamic regulation of HSF1 involves the major heat shock proteins Hsp70 and Hsp90. Recent advances in the understanding of this regulatory circuit in Saccharomyces cerevisiae have shown that the Hsp70 Ssa1 acts as a sensor for some proteotoxic stresses and is capable of a direct interaction with Hsf1. This work continues to explore the complex regulatory interaction between Hsf1 and Ssa1. I …

Characterization Of Microtubule Organizing Centers In The Genus Protostelium, Including Evolutionary Implications, Ethan Taylor Ozment

Graduate Theses and Dissertations

Microtubule organizing centers (MTOCs) are cellular regions of microtubule nucleation. The best known MTOCs are those associated with the centrosome, but several non-centrosomal MTOCs are known in eukaryotes, especially in land plants. MTOCs are poorly characterized across the breadth of amoebozoan diversity, but are well-known in certain amoebozoan lineages, including the genus of protosteloid slime molds Protostelium. The structure of the MTOC is known for two non-ciliated species, P. nocturnum and P. mycophaga, as well as P. aurantium, which can reversibly become ciliated under appropriate conditions. P. nocturnum and P. mycophaga have acentriolar centrosomal MTOCs while P. aurantium has a …

Inactivation Of Mycobacteria By Radicals From Non-Thermal Plasma Jet, Chaebok Lee, Bindu Subhadra, Hei-Gwon Choi, Hyun-Woo Suh, Han S. Uhm, Hwa-Jung Kim

Faculty Publications - Biological Sciences

Mycobacterial cell walls comprise thick and diverse lipids and glycolipids that act as a permeability barrier to antibiotics or other chemical agents. The use of OH radicals from a non-thermal plasma jet (NTPJ) for the inactivation of mycobacteria in aqueous solution was adopted as a novel approach. Addition of water vapor in a nitrogen plasma jet generated OH radicals, which converted to hydrogen peroxide (H2O2) that inactivated non-pathogenic Mycobacterium smegmatis and pathogenic Mycobacterium tuberculosis H37Rv. A stable plasma plume was obtained from a nitrogen plasma jet with 1.91 W of power, killing Escherichia coli and mycobacteria effectively, whereas addition of …

The Contribution Of Foliar Fungi To Agricultural Soil Microbiomes In An Organic Cropping System., Derek R. Newberger

Creative Activity and Research Day - CARD

With finite arable land available to support a growing human population, sustainable agricultural techniques are increasingly needed to provide long-term food security. Traditionally, the focus of using cover crops as a technique in organic agriculture has been on the improved nutrient and physical properties of soil that result from their use. However, recent technological developments in sequencing have enabled a new window into the benefits of plant microbiomes in agriculture that extend beyond these traditionally touted effects. This project will investigate one relatively under-described effect of using cover cropping systems – the transfer of microbes from plants to soil. Specifically, …