Environmental Microbiology and Microbial Ecology Commons^™

Preliminary Analyses Of The Diversity Of Soil Microbes On The Campus Of The University Of The Incarnate Word, Viridiana Wheeler

Theses & Dissertations

Soil samples were examined outside Bonilla Science Hall on the campus of the University of the Incarnate Word in San Antonio, Texas, at three time points between the calendar years 2016 and 2017. These time points correspond to Fall, Winter, and Spring. Samples were taken at two topsoil depths, 1 cm and 4 cm, to determine if there is a difference in bacterial load or distribution across the time frame examined.

Soil samples were diluted and plated on nutrient agar plates in order to identify unique colony morphologies. A total of 132 distinct morphological isolates were identified and sequenced. Of …

Range-Wide Prevalence And Impacts Of Pseudocercosporella Inconspicua On Lilium Grayi And An Assessment Of L. Superbum And L. Michauxii As Reservoirs, Cindy L. Barrett

Electronic Theses and Dissertations

Lilium grayi (Gray’s Lily), a southern Appalachian endemic species, is threatened by a Lilium-specific fungal pathogen, Pseudocercosporella inconspicua. The disease is characterized by tan lesions that can cause early senescence, while also lowering seed production and viability. This project tested for P. inconspicua conidia and accessed health at nine locations. The disease was present and ubiquitous across the range of L. grayi. Through identification of P. inconspicua conidia in the field, L. superbum (Turk’s Cap Lily) was identified as an additional host, while L. michauxii (Michaux’s Lily) was disease-free. However, infection was inducible in both species. With …

Burkholderia Cenocepacia J2315-Mediated Destruction Of Staphylococcus Aureus Nrs77 Biofilms., Rachel Thompson

College of Arts & Sciences Senior Theses

Cystic fibrosis (CF) is an inherited disorder that affects over 30,000 people in the US and more than 70,000 people worldwide. Recurring bacterial infections in CF patients result in tissue damage that dramatically lowers respiratory function and are ultimately fatal. The formation of bacterial biofilms in the mucus and on lung epithelial tissue allows pathogens to be protected from antibiotics and the host immune system, making treatment of infection difficult. The interactions between CF pathogens in co-culture biofilms are not well understood and were examined in this study. Staphylococcus aureus and Burkholderia cenocepacia, two common CF pathogens, were used …

Study Of Rickettsia Parkeri Colonization And Proliferation In The Tick Host Amblyomma Maculatum (Acari: Ixodidae), Khemraj Budachetri

Dissertations

Amblyomma maculatum (Gulf coast tick) ticks are prevalent across the Atlantic to Gulf Coast region of United States. These ticks are recognized vectors of Rickettsia parkeri, a spotted fever group of Rickettsia (SFGR) known to cause American boutonneuse fever associated with fever and eschar rashes localized to the site of bites. We hypothesized that Rickettsia parkeri colonization and proliferation in the tick vector involve pathogen-symbiont dynamics and tick-pathogen interactions, which influence rickettsial transmission to the victims after tick bites. The rickettsial infection is maintained across the tick life cycle for many generations due to transovarial and transstadial transmission of …

Impact Of Cations On The Sorption Capabilities Of Kaolin Towards Biofilm-Forming Bacteria, Rachel E. Brineman

Georgia College Student Research Events

Biofilm-forming bacteria cause problems for industries such as medical, food, and water treatment. Due to its heterogeneous charges, kaolin is capable of sorption of these microorganisms. These charges are impacted by pH and cations, which change the electrostatic interactions between kaolin particles and microorganisms. Proper pH and cation composition may lead to enhanced sorption. The impact of Al3+ cations on kaolin sorption of Gram negative (E. coli and P. aeruginosa) and Gram positive (B. megaterium and S. aureus) was investigated. Calcined kaolin and Diatomaceous Earth kaolin, which were selected in previous studies, were incubated in triplicates with the above organisms …

Phytohormone Signaling In Chlorella Sorokiniana: Perspectives On The Evolution Of Plant Cell-To-Cell Signaling, Maya Khasin

School of Biological Sciences: Dissertations, Theses, and Student Research

Cell-to-cell communication is a key aspect of microbial physiology and population dynamics, and a cornerstone in understanding the evolution of multicellularity. Quorum sensing in bacteria is a canonical example of microbial cell-to-cell signaling, in which bacteria use small molecule signals in order to monitor their population size and modulate their physiology accordingly. We propose that the evolution of plant hormone signaling arose in unicellular green algae, analogously to quorum sensing in bacteria, and that the complexity of these pathways required the recruitment of increasingly specific enzymes to increasingly sophisticated gene networks throughout the course of phytohormone signaling evolution. Using Chlorella …

Microflora In The Cheek Pouches Of Ord's Kangaroo Rat (Dipodomys Ordii) From The Nebraska Sandhills, Devin M. Christensen

UNO Student Research and Creative Activity Fair

The microflora living within the Ord’s kangaroo rat (Dipodymis ordii) cheek pouches has never been extensively studied before. Kangaroo rats use their cheek pouches to transport seeds and grasses in their mouths that they later store. It is predicted that the cheek pouches harbor fungal and bacterial growth that could be either helpful or harmful to the kangaroo rat and its environment. 8 kangaroo rats were humanely captured using Sherman live traps in the Nebraska Sandhills; their cheek pouches were swabbed, and the microorganisms obtained were grown on agar plates and in liquid media until an adequate amount …

Diversity And Biocide Susceptibility Of Fungal Assemblages Dwelling In The Art Gallery Of Magura Cave, Bulgaria, Milena M. Mitova, Mihail Iliev, Alena Nováková, Anna A. Gorbushina, Veneta I. Groudeva, Pedro M. Martin-Sanchez

International Journal of Speleology

Magura Cave, north-western Bulgaria, possesses valuable rock-art paintings made with bat guano and dated from the period between the Eneolithic and Bronze Ages. Since 2008, the Art Gallery is closed to the general public in order to protect the paintings from vandalism, microclimatic changes caused by visitors and artificial illumination, and the consequent growth of fungi and phototrophs. Nevertheless, some tourist visits are allowed under the supervision of cave managers. This study provides the first scientific report on cultivable fungal assemblages dwelling different substrata in the Art Gallery. A total of 78 strains, belonging to 37 OTUs (Ascomycota 81%, Zygomycota …

An Assessment Of Potential False Positive E.Coli Pyroprints In The Cplop Database, Skyler A. Gordon

Master's Theses

The genetic information found in each species of organism is unique, and can be used as a tool to differentiate at the molecular level. This has caused rapid genotyping methods to become the cornerstone of a new area of research dependent on reading the genome as a form of identification. One of these specific identification methods, known as pyroprinting, relies on the small variation of DNA sequences within the same species to develop a unique, reproducible fingerprint. By simultaneously pyrosequencing multiple polymorphic loci within the ribosomal operons known as the intergenic transcribed spacers, a reproducible output is obtained, known as …

Beyond The Obvious: Emerging Contaminants And Biogeochemistry As A Cause And Solution For Nitrogen Pollution, Stephanie L. Devries

Dissertations, Theses, and Capstone Projects

Following a comprehensive review of the occurrence and impacts of antibiotics and related pharmaceutical compounds on the terrestrial N-cycle, three experiments were performed to explore the topic of biogeochemistry as a source or a sink for N-pollution. The first of these experiments addresses the question of whether environmentally relevant concentrations of antibiotics (µg·kg^-1) have a significant effect on denitrification or N₂O production, a question that has not been well addressed in previous studies. Having determined that there is a significant shift, the second study aims to comprehensively follow changes to soil N pools and N_{2 …}

Freshwater Fungal Infections, Dennis J. Baumgardner

Journal of Patient-Centered Research and Reviews

Fungal infections as a result of freshwater exposure or trauma are fortunately rare. Etiologic agents are varied, but commonly include filamentous fungi and Candida. This narrative review describes various sources of potential freshwater fungal exposure and the diseases that may result, including fungal keratitis, acute otitis externa and tinea pedis, as well as rare deep soft tissue or bone infections and pulmonary or central nervous system infections following traumatic freshwater exposure during natural disasters or near-drowning episodes. Fungal etiology should be suspected in appropriate scenarios when bacterial cultures or molecular tests are normal or when the infection worsens or …

Microbial Interactions In The Phyllosphere Increase Plant Performance Under Herbivore Biotic Stress, Muhammad Saleem, Nicole Meckes, Zahida H. Pervaiz, Milton B. Traw

Plant and Soil Sciences Faculty Publications

The phyllosphere supports a tremendous diversity of microbes and other organisms. However, little is known about the colonization and survival of pathogenic and beneficial bacteria alone or together in the phyllosphere across the whole plant life-cycle under herbivory, which hinders our ability to understand the role of phyllosphere bacteria on plant performance. We addressed these questions in experiments using four genetically and biogeographically diverse accessions of Arabidopsis thaliana, three ecologically important bacterial strains (Pseudomonas syringae DC3000, Xanthomonas campestris, both pathogens, and Bacillus cereus, plant beneficial) under common garden conditions that included fungus gnats (Bradysia spp.). …

Review Of The Algal Biology Program Within The National Alliance For Advanced Biofuels And Bioproducts, Clifford J. Unkefer, Richard T. Sayre, Jon K. Magnuson, Daniel B. Anderson, Ivan Baxter, Ian K. Balby, Judith K. Brown, Michael Carleton, Rose Ann Cattolico, Taraka Dale, Timothy P. Devarenne, C. Meghan Downes, Susan K. Dutcher, David T. Fox, Ursula Goodenough, Jan Jaworski, Jonathan E. Holladay, David M. Kramer, Andrew T. Koppisch, Mary S. Lipton, Babetta L. Marrone, Margaret Mccormick, István Molnár, John B. Mott, Kimberly L. Ogden, Ellen A. Panisko, Matteo Pellegrini, Juergen Polle, James W. Richardson, Martin Sabarsky, Shawn R. Starkenburg, Gary D. Stormo, Munehiro Teshima, Scott N. Twary, Pat J. Unkefer, Joshua S. Yuan, José A. Olivares

Publications and Research

In 2010,when the National Alliance for Advanced Biofuels and Bioproducts (NAABB) consortiumbegan, littlewas known about themolecular basis of algal biomass or oil production. Very fewalgal genome sequenceswere available and efforts to identify the best-producing wild species through bioprospecting approaches had largely stalled after the U.S. Department of Energy's Aquatic Species Program. This lack of knowledge included how reduced carbon was partitioned into storage products like triglycerides or starch and the role played bymetabolite remodeling in the accumulation of energy-dense storage products. Furthermore, genetic transformation and metabolic engineering approaches to improve algal biomass and oil yields were in their infancy. Genome …

Quorum Sensing In Candida Albicans: Farnesol Versus Farnesoic Acid, Wayne R. Riekhof, Kenneth Nickerson

Kenneth Nickerson Papers

Candida albicans is a clinically important dimorphic fungus that exhibits either a budding yeast or a mycelial-hyphal or pseudohyphal growth, depending on environmental conditions. The yeast-to-mycelia morphologic transition, which is generally regarded as an important virulence determinant, depends on the inoculum size of liquid cultures. The yeast form is favored when cultures are inoculated at > 10⁶ cells∙mL^–1, whereas the mycelial form is favored at inoculum densities < 10⁶∙mL^–1. Farnesoic acid (FA) and farnesol (FOH) are two related sesquiterpene quorum- sensing molecules that, upon accumulation, prevent the yeast-to-mycelial conversion. Oh et al. showed that C. albicans …

Deciphering Fungal Dimorphism: Farnesol’S Unanswered Questions, Kenneth Nickerson, Audrey L. Atkin

Kenneth Nickerson Papers

Candida albicans excretes E,E-farnesol as a virulence factor and quorum sensing molecule that prevents the yeast to hyphal conversion. Polke et al. (2016) identified eed1Δ/Δ as the first farnesol hypersensitive mutant of C. albicans. eed1Δ/Δ also excretes 10X more farnesol and while able to form hyphae, it cannot maintain hyphae. This mutant enables new research into unanswered questions, including the existence of potential farnesol receptors and transporters, regulation of farnesol synthesis, and relationships among farnesol, germ tube formation and hyphal maintenance. The eed1 farnesol hypersensitivity can be explained by higher internal concentrations of farnesol or lower thresholds for response. One …

Media Optimization, Scale-Up And Repeated Fed-Batch Operations For The Production Of 1,3-Propanediol From Glycerol By Halanaerobium Hydrogeniformans, Shivani Kalia

Masters Theses

"The development of renewable energy sources, such as biofuels, is of great interest in today's world due to depletion of fossil fuels and concerns about climate change. The production of the main by-product, crude glycerol, in biodiesel production presents an opportunity for the production of industrially relevant commodities. Crude glycerol in biodiesel waste is highly impure and possesses high salt concentrations and alkalinity, making it infeasible for direct industrial utilization. Moreover, current glycerol purification methods are highly cost-intensive, necessitating a search for cost-effective approaches that are feasible to employ. Genome data analysis of Halanaerobium hydrogeniformans, revealed the metabolic capability …

A Survey Of Β-Lactam Antibiotic Resistance Genes And Culturable Ampicillin Resistant Bacteria In Minnesota Soils, Emily M. Wollmuth

Departmental Honors Projects

Since the discovery of penicillin, antibiotics have been an essential tool in the treatment of bacterial infections and diseases. It is estimated that antibiotics and antibiotic resistance genes have existed for billions of years. With the increasing appearance of resistant pathogenic bacteria, there has been growing concern. β-lactam antibiotics make up the largest portion of the global market, so resistance to these antibiotics is especially alarming. It has been theorized that frequency and type of antibiotic resistance genes vary by area. Previous studies suggest that these differences may be related to antibiotic use in agricultural and urban areas. To survey …

Antibiotic Resistance Genes In Minnesota Soil Bacteria From Areas Of High And Low Ferric Iron, Gunner L. Drossel, Presley Martin Phd

Departmental Honors Projects

Naturally-occurring antibiotic resistance genes in soil bacteria represent a potentially important reservoir of genes that could contribute to antibiotic resistance of human pathogens. It has been reported that over 40 genes in bacterial genomes are controlled by concentrations of ferric iron. We examined the effect of soil metal content on the level of resistance to two antibiotics, ampicillin (Amp) and tetracycline (Tet), and the presence of multiple genes that code for efflux pump-mediated resistance. These pumps act to export toxins (e.g. heavy metals and antibiotics, perhaps). Because of this, growth in heavy metal-contaminated soils might select for antibiotic resistance. Ninety-six …

A First Look At The Microbial Community Of Rabidosa Rabida, A Wolf Spider In Searcy, Arkansas, Patricia Rivera, Ryan Stork, Amber Hug

Journal of the Arkansas Academy of Science

Many diverse animal models have been used to explore the interactions between host organisms and their microbiota. Increased understanding of microbe-host interactions could lead to improved healthcare and drug development. Spiders have venom, digestive fluid, and body fluid components that have been suggested to possess antimicrobial properties that could lead to new and interesting host-microbe interactions. While studies have been published on interactions between bacteria affecting the immune function and behavior of spiders, the spider microbiome has not been established to date. Excreta and body swabs were collected from Rabidosa rabida, a wolf spider typically found on tall grass …

Analysis Of Microbial Diversity In Disturbed Soil, Tyler G. Sanda

Williams Honors College, Honors Research Projects

This paper uses the composition and abundance of microbial species to analyze soil recovery in disturbed land. Surface mining disturbs ecological communities throughout the world. As organizations seek to reclaim these disturbed lands, a proper analysis of recovery is needed. In previous studies, recovery of disturbed land was limited to surface examinations, which do not characterize the possible unseen devastating effects of the subsoil. Soil microorganisms are extremely sensitive to environmental changes such as strip mining. It is proposed that these microorganisms may serve as better indicators of recovery post disturbance. Our analysis indicates microbial recovery, however it may not …