Microbiology Commons^™

Pseudomonas Aeruginosa Exoy Enzymatic Activity Inhibits Exos-Induced Caspase-3/7 Activation But Not Cytotoxicity In Pmvecs, Connor Holm

Poster Presentations

Pseudomonas aeruginosa (P. aer.) is the most common cause of ventilator associated pneumonia (VAP) in ICU patients. Different combinations of exoenzymes (S, T, Y, and U) are found in P. aer. strains. ExoY is most often associated with VAP in ICU patients. ExoY infection of pulmonary microvascular endothelial cells (PMVECs) induces cell rounding but does not activate intracellular caspase-3/7 or cause cell death. ExoS and ExoT infection of epithelial cells leads to caspase-3/7 dependent cell death. Previous studies using epithelial cells show that ExoY alleviates the cytotoxic effects of ExoS and ExoT. Here, we sought to determine whether ExoY inhibits …

Decoding Bacterial Resilience: Srnas And Sigma Factors In Stress Adaptation And Persistence Of Salmonella, Anita Nguyen

Poster Presentations

Small RNAs (sRNAs) are noncoding RNA molecules in bacteria that function primarily to regulate gene expression, including those associated with stress. The Borchert Lab has identified 173 sRNAs and > 500 sRNAs that are responsive to desiccation and carbon starvation (c-starvation), respectively. Prokaryotic transcription involves an RNA Polymerase (RNAP) that transcribes DNA into RNA. RNAP involves sigma factors, which recognize promoters for the initial steps of RNA synthesis. The Borchert Lab has determined that there are significant overlaps between sRNAs expressed in cells subjected to both short-term durations and long-term durations of carbon starvation. Salmonella enterica serovars can have outbreaks associated …

The Impact Of Maternal Age On The Expression Of Transgenerational Plasticity In Daphnia Pulicaria, Calvin Nguyen

2025 Spring Honors Capstone Projects - Archive

Transgenerational plasticity refers to heritable, non-genetic changes in phenotype that persist across multiple generations and can enhance offspring survivability in variable environments. In Daphnia, increasing maternal age has been associated with maladaptive plasticity. To investigate this relationship, six clones were collected from two Wisconsin lakes and acclimated to laboratory conditions through a common garden rearing process. For each clone, ten replicates were generated and evenly divided between young (clutches 2–4) and old (clutches 5–8) maternal age groups. Offspring were exposed to three dietary treatments for three experimental generations: one fed only green algae, one fed only cyanobacteria (a nutritionally …

The Impacts Of Management Practices On Industrial Hemp Chemistry, Physiology, And Microbiome Ecology., Allison Marie Rietman

Electronic Theses and Dissertations

Agroecology incorporates ecology and agronomy to inform crop management. Industrial hemp (Cannabis sativa L.) is a prime system to investigate agroecological questions because it has only recently been authorized for commercial cultivation and its sensitivity to biotic and abiotic stressors is unresolved. Here, I investigate how some conventional management choices, including the application of fungicide, plastic mulch, and irrigation, impact the physiology, chemistry, and microbial ecology of industrial hemp. Overall, I found that industrial hemp can be both resilient and resistant to these stressors, an important development for the industry. In Chapter II, I tested the impacts of fungicide application …

Integration Of Multi-Omics Datasets Evaluating Structural And Functional Features Of The Gut Microbiome In People With Hiv (Pwh)., Aakarsha Vijayakumar Rao

Electronic Theses and Dissertations

Gut dysbiosis characterized by reduced abundance of beneficial butyrate-producing bacteria has been independently linked to HIV-1 infection and heavy alcohol drinking. Further, gut dysbiosis results in loss of gut barrier integrity, microbial translocation and host-specific systemic inflammation. Therefore, to evaluate the functional consequences of structural changes in the gut microbiome, integrated data analysis is imperative. In this dissertation, we perform integrated analyses using data from multi-omics platforms to examine the structural and functional features of the gut microbiome of PWH. Gut microbiome composition was evaluated by sequencing V4 region of 16S rDNA, concentrations of metabolites and host-specific immune markers were …

Novel Chloroviruses With Unique Glycans On Their Major Capsid Proteins, Cayden J. Homolka

Honors Program: Senior Projects (Public)

Chloroviruses, of the family Phycodnaviridae, are large, dsDNA viruses with a genome of 290 to 410 kb. These virus genomes are so large that they are classified as “giant viruses”. Within this genome, up to 16 tRNAs and 330 to 450 proteins are encoded. Among the massive amounts of genes and proteins are unique carbohydrate synthesis/metabolism genes, which are responsible for the glycosylation of chloroviruses major capsid proteins. In most viruses, these proteins are glycosylated by the host enzymes located in the endoplasmic reticulum. Instead, Chloroviruses encode their own glycosylation machinery; essentially decorating themselves. Furthermore, these chlorovirus glycans are unlike …

Investigation Into The Microbiome Of Blow Fly Eggs Using Microseqtm Id, Samantha S. Davis, Drusilla Sheridan, Jennifer Rosati

Undergraduate Research

There is little published research characterizing the microbiome associated with blow fly eggs and how they may affect the colonization behaviors of certain blow fly species. Once deposited, blow fly eggs are rapidly introduced to a diverse range of microorganisms, which can vary depending on the species of blow fly, the environment, and the decomposition stage of the substrate (Junqueira et al., 2017). Since blow flies are among the first insects to colonize decomposing remains, the microbial communities present on their eggs could serve as key indicators of the decomposition stage at the time of egg-laying, thus providing a potential …

Exploring The Role Of Lysine Acetylation During Biofilm Formation In Bacillus Subtilis, Jennifer Nguyen, Briana Ericka Reid, Valerie Carabetta

Rowan-Virtua Research Day

Biofilms are structured communities of bacterial cells encased in a self-produced extracellular matrix, composed of polysaccharides, extracellular DNA, and proteins. Bacteria in a biofilm pose significant challenges in healthcare due to their resistance to disinfectants and tolerance to antibiotics. In some species, histone-like proteins were found to be important structural components of the biofilm. Nε-Lysine acetylation is a widespread post-translational modification (PTM) in bacteria, which can alter a protein’s function. The histone-like protein HBsu in Bacillus subtilis is acetylated at seven sites in vivo. We hypothesized that the acetylation state of HBsu may alter biofilm structure or the genetic programming, …

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 …

Biological Reduction Of Perchlorate In Martian Regolith Simulant Using Azospira Oryzae, Brianna Bernhardt

Honors Program: Senior Projects (Public)

Establishing a sustainable human presence on Mars will require in-situ resource utilization (ISRU) to reduce costly and inefficient resupply missions. Despite containing many of the requirements for agriculture, Martian regolith is contaminated with toxic levels of perchlorate (ClO₄^-), threatening human health and agricultural success. Biological remediation using perchlorate-reducing bacteria offers a promising approach to address these challenges. This study investigated the perchlorate-reducing ability of Azospira oryzae, a facultative anaerobe capable of converting ClO₄^- to chloride (Cl^-) through dissimilatory respiration. A. oryzae was cultured in Martian regolith simulant (MGS-1) amended with 0.0%, 0.5%, …

Investigating The Effects Of Prenatal E-Cigarette Exposure On Postnatal Liver Histology, Emma Mcclellan

College of Arts & Sciences Senior Theses

The electronic cigarette (e-cigarette) entered the American market in the mid-2000s and quickly became popular. This product poses a significant threat to youth with 1.63 million students reporting use in 2024. Adverse health effects to different organs are well known. The liver is less studied, and despite its role in detoxification of e-cigarette chemicals, is a target of injury. Unlike the known effects of cigarettes and nicotine on the liver from adult or prenatal exposure, effects of prenatal exposure to e-cigarettes on liver remain to be defined. The current study investigated the effects of prenatal exposure of e-cigarettes on liver …

Decoding Bacterial Resilience: Srnas And Sigma Factors In Stress Adaptation And Persistence Of Salmonella, Anita Nguyen

Honors Theses

Small RNAs (sRNAs) are noncoding RNA molecules in bacteria that function primarily to regulate gene expression, including those associated with stress. The Borchert Lab has identified 173 sRNAs and > 500 sRNAs that are responsive to desiccation and carbon starvation (c-starvation), respectively. Prokaryotic transcription involves an RNA Polymerase (RNAP) that transcribes DNA into RNA. RNAP involves sigma factors, which recognize promoters for the initial steps of RNA synthesis. The Borchert Lab has determined that there are significant overlaps between sRNAs expressed in cells subjected to both short-term durations and long-term durations of carbon starvation. Salmonella enterica serovars can have outbreaks associated …

Pseudomonas Aeruginosa Exoenzyme Y Enzymatic Activity Inhibits Exoenzyme S-Induced Caspase Activation But Not Cytotoxicity In Pulmonary Microvascular Endothelial Cells, Connor Holm

Honors Theses

Pseudomonas aeruginosa (P. aeruginosa) is the most common cause of ventilator-associated pneumonia in intensive care unit patients. P. aeruginosa utilizes a type III secretion system that injects exoenzymes U, S, T, and/or Y into the host cell cytosol. A majority of clinically isolated P. aeruginosa strains express ExoY often in combination with ExoU and ExoT, or ExoS and ExoT. Host signaling mechanisms in response to intoxication with individual exoenzymes have been extensively studied, yet little is known about host cell response to co-intoxication. In this study, pulmonary microvascular endothelial cells (PMVECs) were infected with P. aeruginosa strains expressing different combinations …

Toxicity And Biodegradability Of Novel Boronium Vs Conventional Ammonium-Based Antimicrobial Compounds In Wastewater Treatment Systems, Noor Shalan

Honors Theses

Quaternary ammonium compounds (QACs) are highly effective as disinfectants, herbicides, and pesticides; thus, overuse causes elevated levels of residual toxicity in domestic and industrial wastewater. QACs can be toxic to essential bacteria breaking down pollutants in wastewater treatment plants (WWTPs) and can remain untreated in effluent, harming the environment, and contributing to antibiotic resistance, posing risks to human health. Novel boronium-based antimicrobial compounds have demonstrated efficacy in eliminating bacteria, fungi, and viruses. If the boronium compounds exhibit lower residual toxicity, they could offer a promising alternative to QACs. Because these compounds are still in development, their potential toxicity to the …

Sars-Cov-2 Modulates Pla2g2d/Pgd2 Signaling To Manipulate Host Immune Response To Increase Disease Severity., Dante L. Hamiel

Electronic Theses and Dissertations

Background: Previous studies suggested that SARS-CoV-2 infection could cause diverse immune and metabolic dysregulations, although the underlying mechanisms remain poorly understood. In addition, viruses may escape the immune response by modulating cellular metabolism, mitochondria, and protein functions indicating that immune or metabolic components may represent novel targets for anti-viral strategies. However, whether immune and metabolic disorders interact or affect each other waits to be determined. On the other hand, previous investigations identified the critical roles of a cell membrane-bound phospholipase PLA₂G2D and its downstream products PGD₂ in regulating the metabolism and inflammation in respiratory system. More importantly, …

Expanding Inducible Epithelial Resistance Against Pneumonia: Novel Virus, Novel Receptor, Michael Longmire

Dissertations and Theses (Open Access)

Pneumonia is the leading infectious cause of death worldwide and presents a continuing risk among immunocompromised patients. Our work has been focused for many years on the phenomenon of inducible epithelial resistance, where activation of the innate immune response in the airway epithelium is necessary and sufficient to produce a pathogen-killing but self-protective environment to prevent severe disease. Inducible resistance is pathogen-agnostic and has been demonstrated against an array of respiratory infections. We achieve this using a combination of pattern recognition receptor agonists – Pam2CSK4 and ODN M362 being the current formulation – which produce synergistic levels of pathogen reduction …

Effects Of Plant Growth-Promoting Microorganisms On Microbial Community Dynamics And Plant Growth Responses Of Aeroponically Cultivated Spinach, Veronica Snow

All NMU Master's Theses

Regional food insecurity caused by the inability to use conventional farming techniques year-round in cold climates increases the need for access to quality, locally sourced, and affordable foods year-round. Shifting from a soil-based system to aeroponics can increase yields, as aeroponic systems are not weather-reliant and can operate year-round. Aeroponics, a subgroup of hydroponics, induces growth by misting nutrient-rich solutions onto the plant roots. These systems use space and water more efficiently and rely less on fertilizers and pesticides but are vulnerable to errors in nutrient application, power loss, and rapid pathogen spread. Adding Vermicompost (VCT) and plant growth-promoting microorganisms …

Serological Evaluation For Leptospirosis On Samples Received By The Connecticut Veterinary Medical Diagnostic Laboratory (Cvmdl), Hayden R. Samuels

Honors Scholar Theses

Leptospirosis is a globally distributed zoonotic disease caused by pathogenic species of Leptospira, motile spirochetes capable of infecting humans and animals. Transmission typically occurs through contact with water or soil contaminated by the urine of reservoirs or infected animals. Although leptospirosis is considered a neglected tropical disease, its geographic range is expanding due to climate change and urbanization. Surveillance remains limited in many regions, especially in the United States. This study aimed to assess the seroprevalence and serovar diversity of Leptospira exposure in a variety of domestic and wild animals submitted to the Connecticut Veterinary Medical Diagnostic Laboratory (CVMDL). …

Exploring The Antagonistic Polymicrobial Interaction Of Alcaligenes Faecalis With Prokaryotic And Eukaryotic Microorganisms, Aly Hargrave

Electronic Theses and Dissertations

Alcaligenes faecalis, a generally nonpathogenic, Gram-negative bacterium, has been observed by our laboratory to possess antagonistic activity against antimicrobial-resistant genera Staphylococcus, Candida, and Bacillus. This study focused on exploring the inhibition mechanism of A. faecalis against the three genera, with an emphasis on S. aureus. A library of A. faecalis transposon mutants was constructed and identified fourteen possible genetic factors linked to this inhibitory activity. Characterization of this inhibition indicated that A. faecalis suppressed S. aureus planktonic and biofilm growth via a contact-dependent mechanism, with pronounced effects during biofilm attachment phase. In a Caenorhabditis elegans …

Impact Of Shear Flow On Marine Biofilms Using Hyperspectral Imaging, Shantanu Mahesh Kore

All Theses

Various microbial communities in marine biofilms cause biofouling on submerged surfaces, posing challenges to marine industries. Despite their ecological and economic importance, biofilms' biomechanical and biochemical responses to hydrodynamic shear stress are insufficiently understood, particularly in dynamic flow conditions. To fill this gap, our study uses an innovative fiber-optic hyperspectral imaging (HSI) system and a supercontinuum laser source to examine marine biofilms' structure, composition, and detachment behavior at different shear stress levels.

To detect spectral and spatial heterogeneity in live biofilms without labeling, we created a custom imaging pipeline that captures reflectance spectra in the 600-850 nm range, targeting microbial …