Microbiology Commons^™

Detection Of Quorum-Sensing Molecules In The Mutualistic Bacteria Vibrio Fischeri Exposed To Simulated Microgravity Using Cell-Based Biosensors., Paulina Slick, Maria C. Tobarra, Alba A. Chavez, Hugo Castillo

Beyond: Undergraduate Research Journal

Bacteria flourish in multiple environments when communicating with each other in a process known as Quorum Sensing. This process is accomplished by the production of small signaling molecules referred to as Autoinducers (AI). This communication allows the bacteria to alter their gene expression in an effort to regulate their cell number, behavior, community formation and virulence. The space environment provides stressful conditions for bacteria as they are exposed to radiation and Microgravity (µG or MG) altering synthesis and concentration of Autoinducers. The purpose of this research was to expose the model system Vibrio fischeri to simulated microgravity using the recently …

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 …

Assessing The Efficiency Of Methotrexate (Mtx) As An Antiviral Drug Against Gammaherpes Virus Replication, Yennifer A. Gaspar Garcia

Honors Projects

It is estimated that ~15% of all cancers are caused by oncogenic virus infections. Two of the top seven cancer-causing human viruses are members of the gammaherpesvirus family: Epstein Barr Virus (EBV) and Kaposi’s Sarcoma Herpesvirus (KSHV). Our lab uses Murine Herpesvirus 68 (MHV-68), a mouse gammaherpesvirus with shares significant genetic homology to KSHV and EBV, as a model system to understand how gammaherpesviruses alter the metabolism of their host during lytic infection to promote their replication. We recently metabolically profiled MHV-68 infected host cells at various time points during the lytic infectious cycle. Our data showed nucleotide metabolism is …

Coxiella Burnetii Manipulation Of Membrane Contact Sites In The Intracellular Niche, Margaret F. Sladek

Theses & Dissertations

Coxiella burnetii is a highly infectious and environmentally persistent bacterium that causes the disease Q Fever. Its intracellular home, the Coxiella-Containing Vacuole (CVV), is formed from fusion of host-derived vesicles and is rich in sterols - yet cholesterol accumulation in the CCV is bacteriolytic. Our lab’s goal is to understand how Coxiella manages intracellular cholesterol levels and survives within the host. One way Coxiella may modulate CCV cholesterol is through membrane contact sites (MCS), areas where molecular complexes bridge two organelles and exchange lipids. This thesis explores how Coxiella uses both a mammalian lipid transfer protein and bacterially-encoded effector …

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 …

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 …

Impact Of Temperature And Microbial Infection On The Honey Bee Hemocytes, Michael E. Oeth

Master's Theses

Introduction

Honey bees (Apis mellifera) rely on hemocytes for immunity, wound healing, and hemolymph homeostasis. While 32°C reflects optimal hive conditions, suboptimal temperatures (22°C) and stressors like pathogens (Varroa destructor, bacteria) or pesticides impair hemocyte function. Using clodronate liposomes (CLD) to deplete hemocytes, we assessed how immune suppression interacts with these stressors.

Methods

Newly emerged (5-day-old) and older (15-day-old) bees were assigned to: CLD, control liposomes (LP), PBS, injection wound, or no treatment. Cohorts were exposed to 32°C (optimal) or 22°C (stressful for non-immunosuppressed bees). Fifteen-day-old bees were challenged with Escherichia coli or Staphylococcus aureus. Survival, hemolymph volume, and hemocyte …

Thymosin Beta-4: A Novel Treatment For Acanthamoeba Keratitis, Victoria A. Murphey

All Theses

Acanthamoeba keratitis (AK) is a severe corneal infection caused by the free-living amoeba, Acanthamoeba. Both stages of its life cycle (trophozoite and cyst) cause infection, primarily in contact lens wearers. It is often misdiagnosed, leading to delayed treatment and poor clinical outcomes. Current treatment options for AK rely on anti-amoebic agents that are toxic to corneal epithelial cells. Further, no single drug can eliminate both forms of the amoeba. Approximately 30% of all AK infections require a corneal transplant.

Thymosin beta-4 (Tβ4) is a G-actin binding protein synthesized in almost all human cells, including corneal epithelial cells. Tβ4 exhibits …

Bibliometric Analysis Of Research Trends Related To Human Immunodeficiency Virus., Madyson E. Johnson, Kaitlyn R. Coffman, Valerie Rivas, Elizabeth Barrett

ATU Scholars Symposium

Human immunodeficiency virus poses major health burden across the globe including the United States of America and has its zoonotic origin from the Simian Immunodeficiency viruses of sooty mangabey monkey and chimpanzee in Africa. Epidemiological trends indicate that even though the mortality rates for HIV are falling globally, the rates of new cases have been rising since 2010 in several countries including the USA. An estimated 0.5% of the human population is currently infected with the virus with countries like USA, India, Nigeria and South Africa carrying the highest burden of the disease. Host receptors such as CD4 and coreceptors …

Biology Department Publications: 2024, Sam Lindgren

Biology Department Bibliographies

This document is a non-comprehensive list of publications made by graduate students, post-doctoral researchers, and faculty members in the Biology Department in 2024. It indexes those publications available through PubMed, and serves as an archival record of the Department's robust scholarly contributions.

College Of Natural Sciences Newsletter, Spring 2025, College Of Natural Sciences

College of Natural Sciences Newsletters and Reports

Page 1 Dean's Message from Dr. Sen Subramanian
Page 2 Student Spotlights
Page 3 Kaushik honored, Three-Minute Thesis, & Ice Cores revealed
Page 4 Alumni Spotlight
Page 5 Day of Scholars
Page 6 Cyanide research, Record Research Expenditures, Adhikari awarded Miller Research Award
Page 8 Hanson Receives NSF Grant
Page 9 Snow Lab Research Team
Page 10 Faculty Awards
Page 11 Drone Day
Page 13 Khalaf Awarded Presidential Award

College Of Natural Sciences 2024 Year-End Publication, College Of Natural Sciences

College of Natural Sciences Newsletters and Reports

Page 2 Dean's Message
Page 3 Department Highlights
Page 4 One Day for State
Page 5 New Students in Wecota
Page 6-8 Faculty Excellence
Page 9 SDSU Physics Students Recognized
Page 9 Prairie Doc Watch Party
Page 10-11 Student Excellence
Page 11 Connections Abroad
Page 12-13 CNS’s Research Centers
Page 14 Connections Abroad
Page 14 Dean Wolf-Hall Retired
Page 15 Outreach Program
Page 15 Events and Traditions
Page 16 Student Spotlight
Page 17 Alumni Spotlight
Page 18-19 SDSU Alum at Paris Paralympics
Page 20 Work Anniversaries & Programs

Genetic Analysis Of Methionine Restriction-Associated Mitochondrial Unfolded Protein Response Signaling., Josh D. Dodge

Biology Dissertations - Archive

The lifespan of an organism is dictated by various genetic and environmental factors. One such determinant is the health of mitochondria which are organelles that mediate various critical cell functions including a significant role in generating the vast supply of cellular energy. Indeed, the gradual decline of mitochondrial function is believed to be a hallmark and possible cause of aging. Paradoxically, mild mitochondrial dysfunction early in life extends lifespan in various model organisms. Cells use diverse approaches to promote mitochondrial homeostasis, including the transcriptional reprogramming of cells by mitochondrial unfolded protein response (UPRmt) to mitigate mitochondrial stress. Consistently, UPRmt activation …

Functional Analysis Of Ligand Binding Domain 2 Of Outer Surface Protein C Of Borreliella Burgdorferi, Gavin Z. Chambers

Theses and Dissertations

Lyme disease, caused by the spirochete Borreliella burgdorferi, is the most common vector-borne infection in North America. A critical determinant of early mammalian infection is outer surface protein C (OspC), a highly variable lipoprotein that is indispensable for spirochete survival but whose precise function remains unresolved. OspC has been proposed to mediate diverse roles, including complement evasion, adhesion, tissue dissemination, and antiphagocytic activity, supporting the view that it is a multifunctional virulence factor. Structural studies have identified two putative ligand-binding domains (LBD1 and LBD2), with LBD2 forming a solvent-exposed crown at the membrane-distal end of the OspC dimer.

To …

Spermidine And Polyamine Blockade As Key Mediators Of Intestinal Epithelial Cell Functions, Madison Lynn Flory

Theses and Dissertations--Microbiology, Immunology, and Molecular Genetics

Frequently, alterations in the composition of the gut microbiota and its metabolites are linked with intestinal diseases, including inflammatory bowel disease and colorectal cancer. However, the direct connections between alterations in the microbiome and disease states often remain elusive. Prior research has identified increases in both polyamines, which are a class of microbial metabolite, and in the abundance of bacteria that can produce polyamines, in a murine colorectal cancer model. Understanding the significance of the interaction between these microbial metabolites and intestinal epithelial cells (IECs) will provide new and expanded evidence of the importance of the gut microbiome in colorectal …

Assessing The Role Of Daily Thermal Fluctuations In The Performance Of Mitochondrial Energy Transduction Of The Centrarchid, Lepomis Cyanellus, Grayson Hofmann

Masters Theses

Freshwater systems are affected by current climate extremes, forcing species found in these systems to withstand drastic changes in temperature. Temperature changes affect these organisms by altering their metabolic rate and energy balance. Increases in temperature can lead to an increase in oxygen consumption, which ultimately increases the need for more energy production. Mitochondrial energy transduction of green sunfish (Lepomis cyanellus) and many other fish species after a thermal insult, has hardly been explored. This study complements the limited research available on mitochondrial function in similar species, as they ignore the possibility of consecutive thermal events, which are …

Reversible Degradation Of Peptidoglycan By Lytic Transglycosylases, Aaron Devereaux

Theses and Dissertations (Comprehensive)

Antimicrobial resistance continues to be a burden on the global healthcare system with an estimated cost of billions of dollars and millions of deaths each year. Recently, there has been little to no development on new antibiotics to treat bacterial infection, and any that are developed become resisted to within a few years. Both Gram-positive and Gram-negative bacteria contain a mesh-like layer called peptidoglycan (PG) that surrounds their cells providing strength, cell shape, and protection from their environments. This layer is a polymer of N-acetylmuramic acid (MurNAc) and N-acetylglucosamine (GlcNAc) connected via a b-1,4-glycosidic bond, with each strand being cross-linked …

Elucidating The Mechanism Of Interleukin-17a Signaling In The Pathogenesis Of West Nile Virus, Farzana Nazneen

Dissertations

West Nile Virus (WNV), a neurotropic flavivirus transmitted by mosquitoes, is a leading cause of viral encephalitis in the United States and remains a significant public health concern. Unfortunately, no vaccine or therapeutic intervention is available against WNV infection. Previous studies, including ours, demonstrated that interleukin-17A (IL-17A) signaling increases the cytotoxic potential of CD8⁺ T cells to facilitate WNV and parasite clearance; however, the molecular mechanism is not understood. IL-17 receptor C (IL-17RC) is an obligatory co-receptor with IL-17 receptor A (IL-17RA) for signaling induced by IL-17A, IL-17A/F, and IL-17F. In this study, we found that IL-17RC deficient ( …

Lack Of Inflammatory Response In Mouse Embryonic Cells To Listeria Infection, Damilola Oyebode

Master's Theses

Approximately 1 in 5 pregnancies in the United States results in miscarriage, with a significant percentage of these losses attributed to failed implantation due to immunological challenges encountered by the early embryo. Recent research has shown that key cell types within mouse blastocysts, including embryonic stem cells (ESCs) and trophoblast stem cells (TSCs), exhibit remarkable resilience against the cytotoxic effects associated with viral infections and embryotoxic cytokines, such as TNFα and IFNγ, both of which are known to hinder blastocyst development. However, the immune properties of the preimplantation stage embryo, specifically the blastocyst, remain poorly understood. Using mouse cell model, …

Bactericidal Mechanism Of Peracetic Acid Against Salmonella Mediated By Reactive Oxygen Species, Mohammed Khalid Wheib Al-Doury

Graduate Theses and Dissertations

Peracetic acid (PAA) is extensively used as a bactericidal agent in poultry processing to reduce foodborne pathogens, including Salmonella enterica serotype Typhimurium (S. Typhimurium). Despite its widespread application, the exact mechanisms underlying its bactericidal effects, particularly the role of reactive oxygen species (ROS), remain incompletely understood. This dissertation examines the role of ROS in PAA-mediated bacterial killing and explores both genetic and metabolic factors that influence bacterial susceptibility to PAA. Findings from these studies have implications for enhancing the efficacy of PAA, thereby improving food safety practices in the industry.

The first study investigates ROS as a central component …

Differential Responses Of Human Neutrophils To Legionella Species., Hannah E. Hanford

Electronic Theses and Dissertations

Legionella species are Gram-negative facultative intracellular bacterial pathogens commonly found in freshwater or soil environments where they survive and replicate within their natural protozoan hosts. Humans serve as an accidental host for Legionella species after inhalation of contaminated aerosolized water droplets or soil particles enabling the bacteria to enter the lungs, infect alveolar macrophages, and result in severe pneumonia. Evasion of degradation and proliferation within alveolar macrophages by Legionella species and manifestation of “Legionnaires’ disease” is dependent on the Dot/Icm type IV secretion system (T4SS). The T4SS apparatus is a needle-like channel for translocation of over ~350 effector proteins, depending …

Electric Potential Energy Optimized 3d Radial Sampling Trajectories For Mri, Christopher Huynh, Datta Singh Goolaub, Christopher K Macgowan

Faculty, Staff and Students Publications

A novel method for creating “golden” 3D center-out radial MRI sampling trajectories was developed and analyzed. This method, called ELECTRO (ELECTRic potential energy Optimized), uses repulsive forces to minimize electric potential energy. An objective function , the electric potential energies of all subsets of consecutive readouts in a 3D radial trajectory, and its reduced form were minimized using a multi-stage optimization strategy. A metric called normalized mean nearest neighbor angular distance (NMNA) was proposed for describing distributions of points on a sphere. ELECTRO and other relevant golden trajectories were compared in silico using NMNA and point spread function analysis. Consecutive …

Complete Genome Sequence Of An Indian Outbreak Strain Of Chikungunya Virus, Eshna Laha, Deepak Jena, Viplov K. Biswas, Sharad Singh, Sunil K. Raghav, Asit K. Pattnaik, Soma Chattopadhyay

Nebraska Center for Virology: Faculty Publications

Here, we report the complete genome sequence of an Indian strain of chikungunya virus isolated from an infected patient from Hyderabad, Andhra Pradesh, India, during a massive outbreak in 2005–2006. The genome length spans 11,811 nucleotides and has a poly(A) tail of 29 residues at the 3′ end.

Manipulation Of Cellular Proliferating Cell Nuclear Antigen (Pcna) During Herpes Simplex Virus Type 1 Infection, Jessica Packard, Jill A. Dembowski

Electronic Theses and Dissertations

Herpes simplex virus type 1 (HSV-1) is a double stranded DNA virus that replicates within the nucleus of host cells. Using accelerated native isolation of proteins on nascent DNA (aniPOND), cellular proteins were found to associate with HSV-1 replication forks. One host factor of interest is proliferating cell nuclear antigen (PCNA), the DNA sliding clamp that tethers DNA polymerases and DNA damage response proteins to replicating cellular DNA. Although HSV-1 encodes its own DNA polymerase processivity factor (UL42), PCNA plays a key role in HSV-1 infection. We used commercially available PCNA inhibitors and short hairpin RNAs (shRNA) to investigate how …

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 …

Protein Nanoparticles As Vaccine Platforms For Human And Zoonotic Viruses, Kush Kumar Pandey, Bikash R. Sahoo, Asit K. Pattnaik

Nebraska Center for Virology: Faculty Publications

Vaccines are one of the most effective medical interventions, playing a pivotal role in treating infectious diseases. Although traditional vaccines comprise killed, inactivated, or liveattenuated pathogens that have resulted in protective immune responses, the negative consequences of their administration have been well appreciated. Modern vaccines have evolved to contain purified antigenic subunits, epitopes, or antigen-encoding mRNAs, rendering them relatively safe. However, reduced humoral and cellular responses pose major challenges to these subunit vaccines. Protein nanoparticle (PNP)-based vaccines have garnered substantial interest in recent years for their ability to present a repetitive array of antigens for improving immunogenicity and enhancing protective …

Understanding The Non-Canonical Regulation Of Srebp In Aspergillus Fumigatus, Muhammad Abubakar Khan

Dartmouth College Ph.D Dissertations

Aspergillus fumigatus is an opportunistic fungal pathogen causing invasive pulmonary aspergillosis (IPA), with high mortality rates in immunocompromised individuals. Adaptation to the hypoxic microenvironment of IPA is crucial for fungal virulence. The transcription factor SrbA, a Sterol Regulatory Element-Binding Protein (SREBP) homolog, plays a key role in this hypoxic response and regulates genes involved in hypoxic growth, sterol biosynthesis, and azole resistance, making it an attractive therapeutic target.

However, SrbA activation in A. fumigatus lacks critical components of the canonical SREBP pathway, such as SCAP, Site-1 protease (S1P), and Site-2 protease (S2P). Instead, the rhomboid protease RbdB, signal peptide peptidase …

Efficacy Of Mcl-1 Inhibitors In Multiple Myeloma Cells Resistant To Bortezomib, Emily Nelson, Omar S. Al-Odat, Sabrina M. Paparo, Daniel A. Guirguis, Gabriella Yao, Manoj Pandey, Subash Jonnalagadda, Tulin Budak-Alpdogan

Rowan-Virtua Research Day

Multiple myeloma (MM) is a type of cancer that affects plasma B cells. Patients with MM often experience frequent relapses and can develop resistance to drugs. As a medical researcher, it is important to understand the role of Mcl-1 in preventing intrinsic apoptosis and drug resistance. Mcl-1 belongs to the anti-apoptotic subgroup of Bcl-2 family proteins and plays a crucial role in these processes. Mcl-1 plays a crucial role in driving disease progression and contributing to drug resistance in MM. It has been observed that there is an increased expression of Mcl-1 in 52% of patients with MM during diagnosis, …

Fiddler Crab Gut Microbiomes As An Indicator For Eutrophication Due To Waste-Water Contamination In Estuaries, Madison L. Geraci

Honors Theses

Estuaries are unique biogeochemical zones in coastal systems that provide a myriad of ecological functions: providing habitat for critically important fishery species, diverse species of plants and animals, and contributing to nutrient cycling. Estuaries are vulnerable to anthropogenic stressors as they are intersections between marine and terrestrial communities and are often the hotspot of coastal development and activity. Estuarine sediments act as repositories for anthropogenic contaminants, including excess nutrient runoffs and waste-water pollution that can cause states of eutrophication. Microorganisms are sensitive to these environmental changes, presenting a unique opportunity of being useful bioindicators of environmental stress. Isolating microorganisms from …