Molecular Genetics Commons^™

Exploring Competitive Dynamics Between Pseudomonas Baetica And Salmonella In A Polymicrobial System, Braxton E.M. Stout

Electronic Theses and Dissertations

The global rise in antimicrobial resistance has catalyzed a greater focus on polymicrobial research aimed at characterizing microbial interactions and uncovering new therapeutic strategies. Though it has long been of interest, environmental soil-derived bacteria remain largely under-represented in research and thus uncharacterized in this field. This project aimed to identify soil microbes that display inhibitory mechanisms to potential nosocomial pathogens. Soil sample S1S3-2 displayed inhibitory phenotypes toward numerous bacteria and was identified as Pseudomonas baetica. In both planktonic and biofilm growth, P. baetica was able to inhibit Salmonella arizonae through a contact-dependent and temperature-dependent manner. Screening of a transposon insertion …

The Role Of Seed Mix Characteristics And Soil Amendments During Post-Agricultural Prairie Restoration, Valerie N. Thurston, Michaela J. Woods, Madelaine Gregory, Mary C. Lloyd, Ryan W. Mcewan

Biology Faculty Publications

Introduction: Prairie restoration on degraded lands may be influenced by seed mix characteristics, including species richness and legume establishment. Soil amendments may facilitate restoration; however, the practical usefulness of techniques such as applications of whole soil and leaf mulch remains relatively unclear.

Objectives: We assessed whether increasing species richness and legume content in seed mixes enhances prairie restoration success and examined how soil amendments interact with seed mix composition to influence cover, species richness, diversity, and legume establishment.

Methods: We conducted a field experiment on a 12-ha post-agricultural site in Ohio, U.S.A. Twenty 50 × 50 m plots received one …

An Investigation Of Entamoeba Histolytica Chitin Synthases And Other Encystation Factors In Early Encystation, John N. Talledo

All Theses

Entamoeba histolytica is a food-and-water-borne human protozoan pathogen that relies on a two-stage life cycle for successful proliferation outside of the host. E. histolytica exists in its dormant cyst form while outside of its host and converts to the motile trophozoite (amoeba) form in the small intestine. The trophozoites colonize the large intestine to cause symptomatic disease in ~10% of infections, resulting in ~100 million cases of amoebic dysentery each year. Trophozoites can convert back to the cyst form, which is shed in feces to continue the infection cycle.

Currently, there is a lack of understanding of the exact molecular …

Genetic Screen For Regulators Of Pol4, A Dna Repair Polymerase In Saccharomyces Cerevisiae, Pasang Dolma Sherpa

Theses and Dissertations

In Saccharomyces cerevisiae, DNA polymerase 4 (POL4) is the beta repair polymerase, the product of the POL4 gene, and is involved in base excision repair (BER) and microhomology-mediated end joining (MMEJ). Despite its involvement in these repair pathways and its conservation across eukaryotes, deletion of POL4 shows no detectable phenotype under standard laboratory conditions. I hypothesized that unknown genes act as backup systems, providing redundant activities that allow pol4Δ cells to survive. To test this, a genetic screen for mutants showing synthetic lethality with pol4Δ was implemented. I constructed a strain lacking the POL4 gene and carrying …

Validation Of A Real-Time Pcr Laboratory Developed Test For The Detection Of Pneumocystis Jirovecii In Bronchoalveolar Lavage Samples, Caitlyn Moon

Honors Scholar Theses

Pneumocystis jirovecii is an opportunistic, host-obligate fungal pathogen responsible for causing P. jirovecii pneumonia (PJP) in humans. PJP is treated with trimethoprim-sulfamethoxazole (TMP-SMX), a strong broad-spectrum antibiotic that carries risk of renal and hepatotoxicity. Therefore, rapid diagnosis or exclusion of PJP is crucial to ensure PJP-positive patients receive effective treatment and PJP-negative patients avoid unnecessary antibiotics. Unlike most microorganisms, P. jirovecii cannot be cultured, presenting complications for the typical methods of diagnosing fungal pathogens. Historically, the gold standard for diagnosis was direct microscopic examination with stains such as methenamine silver and calcofluor white, but this diagnostic technique requires highly skilled …

Metagenomic Profiling Of Gut Microbiome Signatures Across Liver Disease Stages And Hcv-Related Hepatocellular Carcinoma In Egyptian Patients, Marwa A. Zahra

Theses and Dissertations

Dysbiosis in the gut microbiome, particularly concerning the synchronous crosstalk between the gut and the liver, has been associated with various diseases. This study profiles the gut microbiome in liver diseases among Egyptian patients, with a focus on the hepatitis C virus (HCV) and hepatocellular carcinoma (HCC), both of which are highly prevalent in Egypt. Utilizing shotgun metagenomic sequencing, we analyzed microbial gene catalogs and taxonomic profiles from 46 Egyptian patients categorized into five groups: healthy individuals, liver disease patients of different etiologies, post-HCV, treated HCV, and HCV-HCC patients. Healthy and treated HCV patients exhibited distinct microbial profiles characterized by …

Oral Streptococcus And Vitamin B12 Deficiency In E-Cigarette Users: A Microbial–Nutrient–Neurotransmitter Axis Linking To Mood Disturbances, Maryam Sabah Naser, Ali Jabbar Abd Al-Hussain Alkawaz, Ali Abbas Hashim Almusawi, Ali Jalil Obaid, Hasanain Ayed Mohammed Al-Khafaji, Reihaneh Sabbaghzadeh

Karbala International Journal of Modern Science

Background: With the rising popularity of e-cigarettes, questions have emerged regarding their broader influence on oral ecology, nutrient absorption, and psychological health. Disruptions in the oral microbiome may alter vitamin B12 dynamics. This, in turn, may indirectly influence serotonin biosynthesis and mood regulation.

Methods: An observational cross-sectional study involved 150 young adults segregated into groups of 50 each as vapers, smokers, or non-users. Streptococcus sanguinis and vitamin B12 metabolism-related variable statuses methylmalonic acid and holotranscobalamin were quantified in samples, along with inflammatory markers interleukin-6, kynurenine/tryptophan ratio, and serotonin. Statistical techniques, including ANOVA and the Kruskal-Walli’s test, correlation, and serial mediation …

Assessing The Impact Of Storing Water Samples At Ambient Temperature On Plankton Metabarcoding, Stephanie N. Lievano

Honors Undergraduate Theses

Increasing incidence of Harmful Algal Blooms (HABs) has led to fish kills, air quality hazards, and economic impacts. One economic impact is on tourism, one of the main sources of Florida’s income, where billions of dollars are lost to such events. The Florida Fish and Wildlife Conservation Commission Fish and Wildlife Research Institute (FWC-FWRI), with the help of collaborators, collects water samples from across the state for HAB monitoring. These samples are stored at ambient temperature for up to 24 hours which could directly affect data analyses. Here, in collaboration with FWRI-FWC, I investigated whether this storage technique affects plankton …

Coordinating The Layers: Regulation Of Peptidoglycan Synthesis And Cell Wall Assembly In Mycobacterium Smegmatis By Murj And Pgfa, Karen Emmanuella Samaga-De-Tembiwa

Biology Dissertations

The mycobacterial cell envelope consists of three covalently linked layers whose synthesis must be coordinated to maintain structural integrity during polar growth. While the biosynthetic enzymes for each layer are well characterized, the molecular mechanisms that coordinate synthesis across layers have remained poorly understood. This thesis investigates two essential transmembrane proteins, PgfA and MurJ, that regulate peptidoglycan metabolism in Mycobacterium smegmatis and provide new insight into how mycobacteria synchronize cell wall assembly.

We present evidence that PgfA functions as a bifunctional regulator that links peptidoglycan metabolism to the availability of trehalose monomycolate (TMM), a key mycolic acid precursor. Through epistasis …

Structure And Function Studies On Trna Splicing Endonuclease, Justin G. Underwood

Dissertations and Theses (Open Access)

A subset of eukaryotic pre-tRNAs have introns that must be spliced out to become mature molecules capable of functioning in translation. This essential processing step is performed by tRNA splicing endonuclease (TSEN), a highly conserved heterotetramer with two catalytic and two structural subunits. In addition to this conserved function, archaeal TSEN also processes pre-rRNA and yeast TSEN cleaves some mRNAs that encode mitochondrial proteins to initiate mRNA degradation. Interestingly, single amino acid mutations in TSEN cause the human Mendelian disease pontocerebellar hypoplasia (PCH) by an unknown mechanism. Recently, several groups have determined the structure of human TSEN, revealing similarities and …

Fostering Entrepreneurial Thinking And Practice Through Teaching And Learning Integration, Mohammad G. Sabbir

Learning and Educational Center Virtual Teaching and Learning Conference

This session explores an innovative, evidence-based approach to integrating entrepreneurial thinking into undergraduate neuroscience education through hands-on gene editing experiences. Using the commercially available Bio-Rad CRISPR/Cas9-based “Out of the Blue” kit for bacterial LacZ gene editing, students are guided not only through the scientific principles underlying modern gene editing technologies but also through the entrepreneurial challenge of replicating and manufacturing the kit using existing lab resources. This model empowers students to extend their learning beyond the classroom by engaging in cost-effective, scalable biotechnology practices—particularly valuable for institutions with limited funding. Classroom-based research demonstrates increased student engagement, deeper conceptual understanding, and …

Enhancing Preparedness: A Genetic Study Of Sar-Cov-2 And Other Microbial Public Health Threats In Wastewater From A College Town, Christian N. Hutchinson

Master's Theses

Problem

The SARS-CoV-2 (COVID-19) pandemic revealed both the systemic vulnerabilities of our healthcare system as well as the importance of timely, localized data for informing public health responses. Traditional testing approaches were essential but often failed to capture the full extent of viral spread, especially in those with mild or asymptomatic conditions that relied on at home testing. This underreporting hindered effective allocation of resources and made developing effective intervention strategies difficult. We also realized the potential for wastewater surveillance to be applied to tracking antimicrobial resistance gene markers. Taken together, this approach should have important implications for improving public …

Enhancing Cataract Surgery Outcomes: Optimal Use Of Pre- And Post-Operative Eye Drops, Keith Skolnick M.D., Anu Valiaveedu

Mako: NSU Undergraduate Student Journal

Many preoperative and postoperative cataract patients struggle with comprehending the use of prescription medication as directed. Language barriers and low health literacy levels are major factors contributing to improper use of prescriptions. To increase patients comprehension, the Fort Lauderdale Eye Institute employed an educational intervention consisting of a live presentation and an instructional video. Results found that 44% of patients were hesitant to ask questions to clinical staff, 32% felt overwhelmed, and nearly 70% lacked confidence in using their prescribed eye drops. Following the intervention, 91% of patients reported increased confidence in their medications, and most indicated that the video …

A Toi Rna Editing In Three Members Of The Microbotryum Violaceum Fungal Complext And Characterization Of Adar Genes Of Microbotryum Superbum., Shikhi Baruri

Electronic Theses and Dissertations

A-to-I RNA editing is a process that occurs post-transcriptionally. Through this process, adenosine (A) is replaced by inosine (I) in RNAs by adenosine deaminase enzymes that act on the single-stranded RNA. These enzymes, also known as ADARs, act on RNA. The translation and splicing mechanisms subsequently interpret inosine as guanosine (G), which effectively alters genetic information. This kind of RNA alteration can cause both nonsynonymous and synonymous changes in codon, which may have an impact on protein function. A group of over 89 basidiomycete fungal species known as the Microbotryum violaceum complex infects a similarly large group of plant host …

Phylogenetic Analysis Of Ftsz In Wolbachia: Implications For Host Specificity, Anwar Rovik, Ayu Rahayu

Makara Journal of Science

Wolbachia are the most prevalent and successful endosymbiont in invertebrates and are categorized into 21 supergroups based on genetic phylogeny. The filamenting temperature-sensitive Z (FtsZ) protein is essential for bacterial cell division and is hypothesized to play a role in Wolbachia's control of host reproduction. However, despite FtsZ's importance, little is known about its diversity and function within Wolbachia. This study investigated the variability of the FtsZ-encoding gene among Wolbachia strains and their hosts. FtsZ gene sequences were retrieved from the National Center for Biotechnology Information database, and representative sequences were randomly selected from each host species and analyzed …

Investigating A Link Between Dna Repair And Dna Replication In Escherichia Coli Using A Bacterial Two-Hybrid System, Lo Cooper

University Honors Theses

Cells rely on nucleotide excision repair (NER) to remove bulky DNA lesions, such as those caused by UV light. In Escherichia coli, NER involves the UvrABC complex, and includes two main pathways, global genomic repair and transcription-coupled repair (TCR). While TCR, which preferentially removes lesions that block RNA polymerase on the transcribed strand of active genes, is well studied, less is known about whether a similar coupling between repair proteins and replisomes blocked by damaged DNA exists. Such a process has been suggested by a high throughput interactome study, using the replisome subunit HolC as bait and the damage …

Microbial Community And Water Quality Assessment Of Crassostrea Virginica Habitats In Southeast Florida, Stacy Brown

All HCAS Student Capstones, Theses, and Dissertations

Eastern oysters (Crassostrea virginica) are essential habitat-forming species that contribute significantly to coastal water quality due to their filter-feeding behavior. Unlike other coastal regions in the Gulf of Mexico and Northeastern United States, oysters are not commercially managed in Southeast Florida and as a result sparse data exists on locations of the Eastern oyster habitat. Similarly, the benefits of oyster reefs to water quality are also not fully documented in Southeast Florida. Although beneficial and often referred to as keystone habitat building species, populations of C. virginica are not currently listed as protected species so little work has …

Competence Protein Comea And Oxidative Stress In Bacillus Subtilis Stationary Phase Mutagenesis, Angeline Roldan, Sam Schauf

Undergraduate Research Symposium Posters

Stationary Phase Mutagenesis is a process where a bacterium can accumulate mutations in the absence of cell division. This may occur via competent DNA uptake and oxidant DNA damage and repair. ComEA is a transmembrane protein in B. subtilis that is required for the transport of exogenous DNA into the cell. (Figure 1)

Implications Of Type Iv Pilus Retraction For Dna Uptake By Acinetobacter Baumannii, Yafan Yu

Dissertations and Doctoral Documents, University of Nebraska-Lincoln, 2023–

Horizontal gene transfer (HGT) via natural competence allows bacteria to incorporate extracellular DNA (eDNA) into their genomes, facilitating genetic diversity and adaptation. In Acinetobacter species, natural competence depends on DNA binding and uptake mediated by type IV pili (T4P). T4P are dynamic extracellular filaments composed primarily of the major pilin subunit PilA, along with a few minor subunits. T4P drive a range of cellular functions including twitching motility, biofilm formation, and DNA uptake, with some functions dependent on pilus retraction and others not. However, how Acinetobacter T4P bind DNA and how T4P/eDNA interactions impact biofilm formation remain unclear. Here, I …

The Roles Of Rnt1 And Putative Endoribonucleases In Eukaryotic Mrna Degradation, Lee-Ann Notice-Sarpaning

Dissertations and Theses (Open Access)

Endoribonucleases initiate degradation by cleaving RNAs internally. Mutations in these enzymes have been shown to cause diseases such as cancer, developmental disorders, and neurodegenerative diseases. Yet, eukaryotic endoribonucleases have not been well studied, especially with regard to their role in nuclear mRNA degradation. Rnt1 is a Saccharomyces cerevisiae (budding yeast) nuclear endoribonuclease and homolog of human Drosha with well-characterized roles in the processing of ncRNAs. The enzyme recognizes and cleaves double-stranded RNA stems containing a terminal tetraloop with an AGNN consensus sequence. However, the scope and consequence of its function in mRNA degradation has heretofore been unclear. Previous studies have …

Life After Death: Investigating The Resistance And Recovery Of Fungal Communities To Foundation Tree Mortality, Jessie F. Marlenee

Biology ETDs

Tree mortality can have cascading effects on the composition and resilience of interacting fungal communities. Yet, little is known about the impact tree mortality, distinct from abiotic drivers (i.e., drought), has on these communities. This dissertation focuses on the resilience of fungal communities to experimental tree mortality in a piñon-juniper woodland. In chapter one, I found that piñon mortality reduced piñon fine root biomass and piñon mycorrhizal fungal diversity, whereas juniper mycorrhizal fungi were unaffected by juniper mortality. In chapter two, I revealed that piñon mortality altered the composition and spatial structure of mycorrhizal and saprotrophic fungi in the soil, …

The Design, Construction, And Testing Of Mrna Vaccine Against Equine Herpes Virus, Bhawana Devkota

LSU Master's Theses

Equine Herpesvirus-1 (EHV 1) is a worldwide significant pathogen that causes respiratory illness, abortion, and neurological disorders in equine. Current vaccines, including live attenuated, inactivated, and subunit platforms, do not prevent viral latency, mucosal shedding, or cross-strain immunity, requiring alternative approaches. To address these gaps, this project explores the design, synthesis, and in vitro testing of an mRNA vaccine targeting immunogenic EHV 1 glycoprotein (gB, gC, gD, gG, and gM). Epitopes were computationally predicted using the Immune Epitope Database (IEDB), codon-optimized for Bos taurus, and cloned into pUCIDT vectors using SP6/T7 promoters. In vitro transcription (IVT) used nucleotide modifications …

Microbial Source Tracking Protocols For Differentiation Of Fecal Bacteria From Cow, Deer, And Horse, Nika Shams, Michael Beach

Symposium of Student Scholars

Microbial source tracking (MST) attempts to identify specific animal sources of fecal contamination in the environment. While traditional fecal coliform enumeration can give a general measure of contamination, the specificity imparted by modern MST provides a more informative assessment of contaminants and their likelihood to affect human health outcomes.

We have been developing an MST system that detects DNA biomarkers from the gram-negative bacterial genus Bacteroides and the family Lachnospiraceae. They are strict anaerobes found in large quantities in the intestines of animals. Unlike E. coli or Enterococci, host-specific strains of Bacteroides and Lachnospiraceae exist. To this end, we …

Clonal Variation In Effector Gene Expression As A Mechanism For Pathogenic Adaptation In Magnaporthe Oryzae, Rebekah J. Ellsworth

Theses and Dissertations--Plant Pathology

Magnaporthe oryzae is a filamentous fungal pathogen that causes destructive diseases in cereals, including rice blast, wheat blast, and gray leaf spot. It is responsible for 10–30% annual yield losses in rice (Nalley et al., 2016) and up to 100% loss in wheat under favorable conditions (Kohli et al., 2011). Disease management typically relies on the use of resistant cultivars, but M. oryzae rapidly overcomes host resistance by mutating or deleting avirulence (AVR) genes recognized by host immune receptors. This rapid adaptation, often occurring within one to two growing seasons, presents a major challenge to breeding for durable resistance.

The …

Presence Of The Ade Multidrug Systems And Response To Triclosan Exposure In Acinetobacter Baumannii From Animal Origins, Sirawit Pagdepanichkit, Rungtip Chuanchuen

The Thai Journal of Veterinary Medicine

Thirty Acinetobacter baumannii from animal origins were obtained from 210 animal carcasses submitted for post-mortem examination, including dogs (n=112), cats (n=45), rabbits (n=17), birds (n=15), pigs (n=7) and exotic animals (n=14). All the isolates were evaluated for antimicrobial susceptibility with absence and presence of efflux inhibitors i.e. reserpine and carbonyl cyanide m-chlorophenylhydrazone (CCCP) and expression profile of important six multidrug efflux systems (i.e. AdeABC, AdeDE, AdeFGH, AdeIJK, AbeM and AmvA). Fifteen isolates expressing different Ade multidrug efflux pumps were selected for determining transcription levels and regulatory mutations. A continuous in vitro exposure experiment with benzalkonium chloride, chlorhexidine and triclosan …

Effects Of Microplastic Biofilms On An Anthropogenically Impacted Suburban Lake, Paris M. Velasquez

Masters Theses

Plastics have been observed in every location on the planet, and their prevalence in the environment is due in part to their strong resistance to degradation. Inland lakes are susceptible to plastic pollution by highway runoff, which contains plastic fragments of brake pads, car tires, litter, and road paint. These plastics eventually enter freshwater environments and degrade into microplastics (

Antarctic Glacier Melting Modeling Distribution Of Bacterial Community Structure, Corina Itcus, Constantin Marin, Soon Gyu Hong, Manuela Elisabeta Sidoroff, Cristian Coman, Cristina Purcarea

FRONTIERS UNBOUND: Exploring Extreme Environments

No abstract provided.

Elucidating The Roles Of Septin Proteins In Thermotolerance And Cell Wall Integrity In Cryptococcus Neoformans, Stephani S. Martinez Barrera

All Dissertations

Cryptococcus neoformans is a globally distributed fungal pathogen responsible for causing cryptococcal meningitis in immunocompromised individuals. This pathogenic yeast must adapt to changes in temperature upon entering the human host. Septin proteins are conserved filament-forming GTPases that assemble as higher-order complexes at the cell cortex to support cytokinesis and morphogenesis in fungal and animal cells. In C. neoformans, four septin homologs (Cdc3, Cdc10, Cdc11, and Cdc12) assemble at the mother-bud neck, contributing to cytokinesis through poorly understood mechanisms. C. neoformans strains lacking the septins Cdc3 or Cdc12 are viable at 25°C, but fail to proliferate at 37°C, and are …

Functional And Structural Analysis Of The Neimann-Pick Disease Type C Pathway To Include Caveolin-1, Anthony Michael Seat

Chemistry and Chemical Biology ETDs

Human disease is often thought of as an all or nothing prospect, either one has the disease or one does not. This does not bear out in clinical or personal experiences, instead demonstrating that disease occurs within a spectrum ranging from presumed unaffected to demonstrably and detrimentally affected.Neimann-Pick disease is one example of this spectrum look into diseased states, with multiple named versions of a phenotypically similar disease. We focus on Neimann-Picktype C (NPC), which is the result of a disruption in the efflux of cholesterol and sphingolipids from the endocytic pathway. NPC demonstrates this concept of a spectrum of …

Optimizing The Expression Of Polyethylene Terephtalate Hydrolase-Encoding Synthetic Gene In Escherichia Coli Arctic Express (De3), Jocelyn Nataniel, Maria Ulfah, Dini Achnafani, Niknik Nurhayati, Gabriela Christy Sabbathini, Sri Rezeki Wulandari, Abinawanto Abinawanto, Is Helianti

Makara Journal of Science

The waste of polyethylene terephthalate (PET) plastic waste in Indonesia is a pressing concern due to its slow degradation and potential environmental damage. One promising solution is to utilize polyethylene terephthalate hydrolase from Ideonella sakaiensis (IsPETase), an enzyme that specifically degrades PET. However, inducing the expression of IsPETase synthetic gene in Escherichia coli BL21 (DE3) has been challenging because much of it remains insoluble. This study aimed to express IsPETase in E. coli Arctic Express (DE3) and optimize the conditions to enhance its production. First, pET22b(+)pelB-IsPETase was inserted into E. coli Arctic Express (DE3). The …