Exploring Competitive Dynamics Between Pseudomonas Baetica And Salmonella In A Polymicrobial System,
2026
East Tennessee State University
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 …
Sporicidal Activity Mechanism Of Lactic Acid And Peracetic Acid On Bovine Pathogenic Bacillus Cereus Spores,
2026
Inner Mongolia Minzu University, College of Animal Science and Technology
Sporicidal Activity Mechanism Of Lactic Acid And Peracetic Acid On Bovine Pathogenic Bacillus Cereus Spores, Xin Zhang, Yunjiao Chen, Jingjing Zhao, Haiying Zheng, Lanlan Liu, Wei Liu, Mingshan Fu, Weijuan Jia, Zelin Jia, Jiayu Cui, Yuhang Zhang, Huisheng Xiong, Yujie Ma, Xueli Wang, Haifeng Wang
The Thai Journal of Veterinary Medicine
In recent years, the pathogenicity of Bacillus cereus (B. cereus) has increased significantly, its host adaptability has continued to expand, and the infection spectrum has also expanded. At the same time, food contamination by B. cereus is also common. Therefore, it is of practical significance to select green, safe and effective inhibitors. Lactic acid (LA) and peroxyacetic acid (PAA) possess good antibacterial properties, making them environmentally friendly, safe, and non-toxic. The purpose of this experiment was to preliminarily explore the inhibition mechanism of LA and PAA on B. cereus spores. The effects of LA and PAA on B. …
Antimicrobial Responses Of Staphylococcus Aureus In Simulated Spaceflight Conditions,
2026
Embry-Riddle Aeronautical University
Antimicrobial Responses Of Staphylococcus Aureus In Simulated Spaceflight Conditions, Mikayla Dutkiewicz, Yegor Bushnev
Discovery Day - Daytona Beach
Microbial persistence in confined environments, such as spacecraft, can pose challenges to astronaut health and habitat maintenance. This project investigates Staphylococcus aureus, a Gram-positive bacterium commonly associated with human microbiota and opportunistic infections, in spaceflight-relevant environmental conditions. Further, this project will assess the influence of the antimicrobial/antioxidant compound quercetin to assess its effects on bacterial growth and virulence under standard Earth gravity and simulated International Space Station (ISS) conditions. This approach will assess whether spaceflight-relevant stressors, including microgravity and radiation, alter treatment efficacy by influencing microbial physiology and antimicrobial susceptibility. Data collection and analysis are ongoing, and results are expected …
Observing Antibiotic Resistance In Bacterial Co-Cultures Under Simulated Microgravity,
2026
Embry-Riddle Aeronautical University
Observing Antibiotic Resistance In Bacterial Co-Cultures Under Simulated Microgravity, Tyler Jenkins, Marina Vaden
Discovery Day - Daytona Beach
Bacteria grow in complex natural environments with multiple factors affecting their growth, metabolism, and physiology. While astronauts are still preparing to travel to Mars, scientists must learn how to simulate a more realistic Martian environment. While a small volume of publications investigates the independent effects of microgravity or Martian regolith on microorganisms (Liao et al., 2025; Allen et al., 2022; Naz et al., 2023; Duri et al., 2025), to our knowledge no current experiments exist on the joint effects of microgravity and Martian simulant on a co-culture. This experiment aims to investigate the effect of a microgravity analog on the …
Investigation Of Biofilm Formation And Osmotic Stress Tolerance Of Nonmotile Escherichia Coli In Simulated Microgravity,
2026
Embry-Riddle Aeronautical University
Investigation Of Biofilm Formation And Osmotic Stress Tolerance Of Nonmotile Escherichia Coli In Simulated Microgravity, Tyler Jenkins
Discovery Day - Daytona Beach
Simulated microgravity presents multiple physiological stressors for astronauts, including bone demineralization, muscle loss, and weakening of the immune system. Bacteria serve as viable model organisms to study physiological changes because of their abundance in the human digestive system and skin. Motility in bacteria plays a significant role in cell survival, but few studies have been conducted on microgravity’s effect on motility phenotypes. While motile strains like Escherichia coli K12 have been studied extensively under microgravity conditions, the effects of simulated microgravity on non-motile strains are largely unknown. To better understand this relationship, the nonmotile E. coli MG1655 strain was inoculated …
Evaluation Of Antimicrobial Resistance In Pathogens Relevant To Long-Duration Space Missions,
2026
Embry-Riddle Aeronautical University
Evaluation Of Antimicrobial Resistance In Pathogens Relevant To Long-Duration Space Missions, Natalie Brattain, Yegor Bushnev, Mikayla M. Dutkiewicz
Discovery Day - Daytona Beach
Antimicrobial resistance is a growing global concern that necessitates the development of effective strategies for selecting appropriate antibiotics, especially in the context of future long-duration space missions, where infection control and treatment options are limited. This study employs the Kirby–Bauer disk diffusion assay to evaluate the antimicrobial susceptibility of Pseudomonas aeruginosa and other clinically and spaceflight-relevant bacterial pathogens such as Klebsiella pneumoniae, Staphylococcus aureus, and Streptococcus pneumoniae. These pathogens will be tested with commonly used antibiotics and potential natural compounds. The pathogens will be cultured and isolated onto Mueller–Hinton agar plates. Antibiotic disks, along with various flavonoids disks, such as …
From Dust To Growth: Microbial Pathways To Extraterrestrial Farming,
2026
Embry-Riddle Aeronautical University
From Dust To Growth: Microbial Pathways To Extraterrestrial Farming, Stefani Capasso Villanueva, Nupur Kulkarni
Discovery Day - Daytona Beach
From Dust to Growth: Microbial Pathways to Extraterrestrial Farming addresses the fundamental challenge of sustaining long-term human habitation on other planets. In the era of the Artemis missions, establishing a cost-effective, bioregenerative food source is critical to reducing logistical dependency on Earth, and mitigating the physiological stressors faced by spacecrew through improved nutrition. This study initially investigated the viability of cultivating Mizuna, a proven ISS model organism, in a substrate of Martian regolith simulant amended with organic compost. Following iterative trials, it was found that the plant survival rate was extremely low, even after varying percentages of compost and simulant. …
Effects Of Microgravity And Gamma Radiation On Biofilm Growth,
2026
Embry-Riddle Aeronautical University
Effects Of Microgravity And Gamma Radiation On Biofilm Growth, Anya Pavlidis, Kaitlyn Mills Mills, Eva Mcclory, Grant Erlinder, Allen Qiu
Discovery Day - Daytona Beach
Biofilms are collections of bacteria that commonly grow on a variety of surfaces. They are resistant to environmental impacts as bacteria fortify themselves to a surface. Biofilms are commonly found on Earth, but more problematically are also found on spacecraft. On the ISS biofilms have developed in spaces like the workout area, food spaces, and most concerning in the Water Recovery System (WRS). Biofilms tend to react differently to attempted cleaning methods in space than they do on Earth and can be located in extremely difficult to reach places. This study aims to explore the effects of gamma radiation on …
Escherichia Coli Concentrations In Sand And Water At Tributary-Influenced Lake Michigan Beaches,
2026
Grand Valley State University
Escherichia Coli Concentrations In Sand And Water At Tributary-Influenced Lake Michigan Beaches, Josie Elaine Kuhlman
Masters Theses
Contamination of public recreational water and sand is a human health concern, creating a management challenge for public health officials. Past research has shown that Escherichia coli can persist in sediment and can be washed into recreational water. Currently, beach monitoring practices only utilize E. coli concentrations in water samples to determine beach safety and do not consider potential exposure to sediment/sand concentrations. In this study, I investigated the relationship between E. coli concentrations in water and sand samples, which will aid public health officials in making more informed decisions about beach closures. I utilized culture-based measurements of E. coli …
Function And Regulation Of Long Polar Fimbriae During Enterohemorrhagic Escherichia Coli Infection,
2026
The Texas Medical Center Library
Function And Regulation Of Long Polar Fimbriae During Enterohemorrhagic Escherichia Coli Infection, Walter J. Galdamez
Dissertations and Theses (Open Access)
Enterohemorrhagic Escherichia coli (EHEC) is a foodborne pathogen that causes severe gastrointestinal disease and hemolytic uremic syndrome. EHEC employs multiple virulence factors to colonize the host intestine, including the locus of enterocyte effacement (LEE) encoded type III secretion system, intimin, and flagella, yet the role of long polar fimbriae (Lpf) in adhesions and infection remains less well understood. Long polar fimbriae can mediate bacterial attachment to host cells in vitro, yet the regulation and function of its two fimbrial operons, lpf1 and lpf2 in vivo remain poorly understood. Preliminary RNA-seq data from zebrafish infected with EHEC reveal that expression of …
Defining The Role Of Spxa1 And Spxa2 In Group A Streptococcus (Gas),
2026
MD Anderson Cancer Center UTHealth Houston Graduate School of Biomedical Sciences
Defining The Role Of Spxa1 And Spxa2 In Group A Streptococcus (Gas), Gretchen Anne Morrison
Dissertations and Theses (Open Access)
Group A Streptococcus (GAS) is a human-restricted pathogen whose global incidence has surged in the post-COVID era. The ability of GAS to shift from a colonizing to invasive phenotype depends on coordinated virulence gene regulation in response to host-imposed stressors. The paralogous global transcriptional regulators, SpxA1 and SpxA2, have emerged as central mediators of these adaptive responses; however, the mechanisms by which these regulators influence both global gene regulation in direct response to external stresses and the host response as a result of regulatory changes remain incompletely understood. Using an integrated multi-omic approach, we define the distinct yet interconnected regulatory …
Mutational Analysis Of Domain Functions In The Yeast Decapping Enzyme Dcp2,
2026
University of Texas Health Science Center at Houston
Mutational Analysis Of Domain Functions In The Yeast Decapping Enzyme Dcp2, Jellisa Ewan, Ambro Van Hoof
Dissertations and Theses (Open Access)
In yeast, the major mRNA decay pathway involves deadenylation of the 3’ poly-A tail, followed by decapping of the 5’ m7Gppp cap and subsequent 5’ to 3’ degradation or 3’ to 5’ degradation. This is carried out by Pan2/Pan3 and Ccr4/Not deadenylases, the decapping enzyme Dcp2, and Xrn1 and RNA exosome exoribonucleases, respectively. The eukaryotic mRNA decapping enzyme complex, Dcp1/Dcp2, is essential in yeast, and deletion of either gene is lethal. However, the deadenylases that act upstream and the 5’ exoribonuclease that act downstream of the decapping step are not, even though they are all highly conserved with no known …
Bridging The Gap In Science Research: Preparing Students For College- Level Research In The Sciences,
2026
University of Connecticut - Storrs
Bridging The Gap In Science Research: Preparing Students For College- Level Research In The Sciences, Victoria Helwig, Yaoguang Li
UConn Library Presentations
Many first-year students enter college unprepared to fully engage with scientific literature and academic library resources. Drawing on experiences from academic librarians working with STEM students, this session explores common gaps in science research skills, including navigating databases, identifying scholarly sources, and understanding the structure of scientific literature. Participants will be introduced to practical strategies and classroom-ready activities to better prepare students for college-level research. Discussion questions: What science research skills do students struggle with most when entering college? How can high school instruction better support these skills? Where can librarians and educators collaborate to support student success?
Analysis Of The Atypical Temperature Dependence And Conformational Changes During Turnover Of A Lactobacillus Chlorogenic Acid Esterase,
2026
Chapman University
Analysis Of The Atypical Temperature Dependence And Conformational Changes During Turnover Of A Lactobacillus Chlorogenic Acid Esterase, Nathaniel Carl, Yianni Tsigaris, Dan Ji, Nora K. Anpree, Kellie K. Omori, Cedric P. Owens
Biology, Chemistry, and Environmental Sciences Faculty Articles and Research
Many bacterial chlorogenic acid esterases (ChlEs) exhibit atypical temperature behavior, featuring activities that barely change with temperature and activity maxima that fall below the thermal denaturation point. This work focuses on a ChlE from Lactobacillus helveticus (Lh–ChlE), which has a flat temperature dependence. First, it was determined that conformational changes during Lh–ChlE turnover are not rate-limiting and that the overall rate depends on the chemical step at all temperatures. Next, Lh–ChlE’s temperature dependence was investigated using a conformational equilibrium model that assumes the existence of a temperature-dependent equilibrium between an active and an inactive conformation and an activation heat capacity …
De Novo Pyrimidine Synthesis Controls Germinal Center B Cell And Plasma Cell Fates And Systemic Autoimmunity,
2026
Thomas Jefferson University
De Novo Pyrimidine Synthesis Controls Germinal Center B Cell And Plasma Cell Fates And Systemic Autoimmunity, Julia L. Weber, Tien Bui, Keomonyroth Nuon, Adam J. Fike, Sophia M. Crocker, Kristen N. Bricker, Anju Maharjan, Wujuan Zhang, Aaron R. Goldman, Sathi Babu Chodisetti, Ziaur S. M. Rahman
Department of Microbiology and Immunology Faculty Papers
Whether and how pyrimidine metabolites promote systemic autoimmunity is unknown. Here, metabolomics and 15N-amide glutamine tracing show enhanced flux through de novo pyrimidine synthesis in systemic lupus erythematosus (SLE)-prone B cells. Temporal inhibition of pyrimidine synthesis dampens SLE-prone but not foreign antigen-specific germinal center (GC), plasma cell (PC), and antibody responses. Uridine monophosphate synthase (UMPS) conditional deletion, however, reveals a B cell-intrinsic requirement of de novo pyrimidine synthesis in foreign antigen-driven and SLE-prone GC, PC, and antibody responses and kidney immune complex deposition. Metabolomics, mitochondrial stress test, metabolic flow cytometry, glycolytic rate assay, and RNA sequencing highlight the importance of …
Systemic Infection Of Beauveria Bassiana In A Stranded Endangered Green Turtle Chelonia Mydas: A Case Report,
2026
College of Veterinary Medicine, National Pingtung University of Science and Technology
Systemic Infection Of Beauveria Bassiana In A Stranded Endangered Green Turtle Chelonia Mydas: A Case Report, Ming-An Tsai, I-Chun Chen, Tsung-Hsien Li
The Thai Journal of Veterinary Medicine
The green turtle (Chelonia mydas) is the most frequently encountered marine turtle species in Taiwan. This study describes the postmortem findings of a juvenile green turtle with injuries to the right foreflipper that was rescued off the Taiwan coast and died after 3 months in rehabilitation. Necropsy revealed large, yellow, multifocal caseous lesions involving the right foreflipper, spleen, liver, kidneys, and lungs. Fungal infection of Beauveria bassiana was confirmed by culture, morphological and molecular characterization, phylogenetic analysis, and histopathological examination. This report provides evidence that B. bassiana is associated with a systemic fungal infection which can be fatal …
In Vivo Expression Profiling Of Listeria Monocytogenes Internalins (Inlf, Inlp, Inlj) And Their Corresponding Host Receptors (Vim, Afdn, Muc2) Using A Rabbit Ligated Intestinal Loop Model,
2026
Department of Medical Biotechnology, College of Biotechnology, Al-Qasim Green University, Babylon 51013, Iraq.
In Vivo Expression Profiling Of Listeria Monocytogenes Internalins (Inlf, Inlp, Inlj) And Their Corresponding Host Receptors (Vim, Afdn, Muc2) Using A Rabbit Ligated Intestinal Loop Model, Nawar Al-Janabi, Nadhim Mushtaq Hashim Al-Bderee, Zahraa M. Madania, Mohanad Jawad Kadhim
Karbala International Journal of Modern Science
Listeria monocytogenes is a Gram-positive pathogen that causes severe infections, particularly in immunocompromised individuals. Internalin genes are important virulence factors that facilitate the bacterium's invasion of host cells. This research aimed to quantify in vivo expression of selected internalin genes (inlF, inlP, and inlJ) and their corresponding host receptors (VIM, AFDN, and MUC2) during L. monocytogenes infection. To achieve this aim, a rabbit ligated intestinal loop model was constructed comprising two intestinal loops. The first loop was injected with 1 mL of L. monocytogenes (1 × 10⁷ CFU/mL), while the second loop was injected with 1 mL of PBS as …
Homocysteine Thiolactone From Translation Proofreading Is An Endogenous Ligand For Cell-Cell Signaling By The Receptor Sdia,
2026
Chapman University
Homocysteine Thiolactone From Translation Proofreading Is An Endogenous Ligand For Cell-Cell Signaling By The Receptor Sdia, Lorenzo Eugenio Leiva, Roberto A. Zúñiga, Gregory J. Phillips, Michael Ibba
Biology, Chemistry, and Environmental Sciences Faculty Articles and Research
Several widespread mechanisms enable cellular communication and coordinate the behavior of bacterial populations. The modules responsible for cellular communication are often found in matching pairs: an enzyme that synthesizes a signal molecule and a specific receptor that decodes it. A notable exception is Escherichia coli SdiA, a homolog of known N-acyl-homoserine lactone (AHL) receptors, for which no corresponding AHL synthase exists. SdiA is an orphan receptor that enables cross-talk by sensing AHLs from other bacterial species. In this work, we investigated whether homocysteine thiolactone (HTL), an AHL-like molecule arising from a proofreading reaction of methionyl tRNA synthetase (MetRS) to correct …
Understanding The Effects Of Simulated Microgravity On Staphylococcus Epidermidis And Escherichia Coli In Co-Culture,
2026
Embry-Riddle Aeronautical University
Understanding The Effects Of Simulated Microgravity On Staphylococcus Epidermidis And Escherichia Coli In Co-Culture, Emma Costa, Mitchell K. Villafania, Makaila Olson, Kareigh N. Gammon, Hugo Castillo
Beyond: Undergraduate Research Journal
With the popularity of space travel increasing, it is important to understand the effects of microgravity on microbial communities as alterations on bacterial interactions can occur. Staphylococcus epidermidis and Escherichia coli are bacteria that are commonly found within human microbiomes. S. epidermidis is a cocci-shaped gram-positive bacterium that is part of the human skin microbiome. However, it can gather on sites of open skin and enter the body leading to an infection. E. coli is a rod-shaped gram-negative bacterium that can be found in the human gut microbiome. The pathogenic strains of E. coli have the potential to cause harmful …
Effectiveness Of Organic Amendments In Enriching Nitrogen In Compost Produced From Organic Fractions Of Market Waste Generated In Dar Es Salaam, Tanzania,
2026
Department of Molecular Biology and Biotechnology, College of Natural and Applied Sciences, University of Dar es Salaam, P.O. Box 35179, Dar es Salaam, Tanzania.
Effectiveness Of Organic Amendments In Enriching Nitrogen In Compost Produced From Organic Fractions Of Market Waste Generated In Dar Es Salaam, Tanzania, Amani Bilula, Ally Mahadhy, Anthony Manoni Mshandete, Amelia Kivaisi
Tanzania Journal of Science
Low nitrogen (N) content remains a key limitation of compost derived from urban organic waste. This study evaluated the effectiveness of selected plant-based organic amendments in enhancing nitrogen content and improving compost quality. Four plant- based organic amendments, Leucaena leucocephala (BN01), Commelina benghalensis (BN02), Morus alba (BN03), and Helianthus annuus (sunflower) cake (BN04), were incorporated into market waste compost at ratios of 1:0.06:0.04, 1:0.06:0.25, and 1:0.06:0.5 (organic waste: sawdust: amendment). Composting was conducted using a 4 × 3 factorial design with three replicates per treatment (n = 36). Temperature, moisture, and pH were monitored throughout the composting period. Total nitrogen, …
