Microbiology Commons^™

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 …

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 …

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 …

Exploring Novel Nutrient Acquisition Mechanisms For Maintaining Energy Metabolism In Toxoplasma Gondii, Melanie Key

All Dissertations

Toxoplasma gondii is an infectious intracellular parasite that establishes infection within various mammalian hosts, including humans. Toxoplasma infects approximately one-third of the global population, making it an impactful pathogen of study. T. gondii is the causative agent of toxoplasmosis, an opportunistic infection that causes severe illness or fatality in immunocompromised individuals or pregnant women. The parasite possesses a very effective invasion strategy, allowing it to cross different tissue types to disseminate infection across the placental and blood-brain barrier. Although there are a few treatments for acute toxoplasmosis, these drugs can produce adverse side effects. These options are not effective against …

Ammonium Chemotaxis In Chlamydomonas Reinhardtii, Gabela Nelson

LSU Doctoral Dissertations

Analysis of ammonium chemotaxis in Chlamydomonas reinhardtii is largely hindered, compared to that of phototaxis, despite equal importance on flagellated microalgal physiology. A major contribution of this shortfall is the lack of proper assay method. We developed a simple Petri dish assay method in which light is homogenously exposed while patterns of the cellular migration are tracked with a function of time. Using the method, new findings were revealed. First, this research presented that a strain lacking the eyespot organelle required for light gradient-sensing exhibits similar chemotactic behavior compared to a wild-type strain, suggesting Chlamydomonas sense an ammonium gradient not …

Hgs-3 The Influence Of A Tandem Cycling Program In The Community On Physical And Functional Health, Therapeutic Bonds, And Quality Of Life For Individuals And Care Partners Coping With Parkinson’S Disease, Leila Djerdjour, Jennifer L. Trilk

SC Upstate Research Symposium

Purpose Statement: Several studies have shown that aerobic exercise can have a positive impact on alleviating symptoms experienced by individuals with Parkinson's disease (PD). Despite this evidence, the potential benefits of exercise for both PD patients and their care partners (PD dyad) remain unexplored. This research project investigates the effectiveness, therapeutic collaborations, and physical outcomes of a virtual reality (VR) tandem cycling program specifically designed for PD dyads.

Methods: Following approval from the Prisma Health Institutional Review Board, individuals with PD were identified and screened by clinical neurologists. The pre-testing measures for PD dyads (N=9) included emotional and cognitive status …

The Plant Disease Triangle Facing Climate Change: A Molecular Perspective, Charles Roussin-Léveillée, Christina A. M. Rossi, Christian Castroverde, Peter Moffett

Biology Faculty Publications

No abstract provided.

Pulsed Electric Fields Sensitize Methicillin-Resistant Staphylococcus Aureus To Antibacterial Therapies And Stimulate Host Immune Responses, Alexandra E. Chittams-Miles

Biomedical Sciences Theses & Dissertations

This research explores the impact of nanosecond pulsed electric fields (nsPEF) on two fronts: their immune stimulatory effects and their potential as a novel strategy to enhance the sensitivity of Methicillin-resistant Staphylococcus aureus (MRSA) to clinically relevant antibiotics. While pulsed electric fields have been reported to have an immune stimulatory effect, the mechanisms responsible for these effects have yet to be determined.

Our investigation addresses the rising concern of MRSA derived skin and soft tissue infections (SSTIs). Consistent with other publications, we found that nsPEF alone cause modest inactivation of planktonic MRSA. We then investigated the effects of nsPEF in …

Investigating Optimal Laboratory Growth Conditions Of Gracilibacillus Halotolerans In Media Supplemented With Salt, Isaac Young

Annual Research Symposium

As interest continues to grow in the field of persister cells and their morphology, there arises an ever-evolving desire to further understand specific strains of bacteria that exemplify the qualities of seemingly anomalous survival regardless of anti-bacterial treatment. In the case of the Gracilibacillus halotolerans, a halotolerant extremophile extracted from the Great Salt Lake with known persistent characteristics, uncovering its optimal growth conditions was essential for future investigations. Identifying the optimal salinity for the growth of G. halotolerans will allow us to standardize our growth methods, uncover several mechanisms of saline tolerance, and add to future investigations of persistence with …

A New Model For Polar Growth In Mycobacteria: The Role Of Wag31 And Mmpl3 In Cell Wall Synthesis, Neda Habibi Arejan

Biology Dissertations - Archive

The disease Tuberculosis (TB) is caused by the pathogen Mycobacterium tuberculosis and was the cause of over one million deaths worldwide in 2023 (World Health Organization, 2023). TB treatment is difficult due to antibiotic tolerance and emerging resistance in Mtb strains. Mycobacterial cells have different regulatory mechanisms that allow them to adjust to myriad environmental stressors: these responses often lead to antibiotic tolerance. Therefore, studying responses to stress will lead to insights about antibiotic tolerance and treatment failure. Here, we specifically study two essential mycobacterial proteins, Wag31 and MmpL3, involved in cell wall metabolism. We show that Wag31 has distinct …

Why Should Early-Career Scientists Publish In Society Journals, Stephen K. Dolan, Lori D. Banks, Wenqi Yu

Molecular Biosciences Faculty Publications

In this editorial, written by early-career scientists, we advocate for the invaluable role of society journals in our scientific community. By choosing to support these journals as authors, peer reviewers, and as editors, we can reinforce our academic growth and benefit from their re-investment back into the scientific ecosystem. Considering the numerous clear merits of this system for future generations of microbiologists and more broadly, society, we argue that early-career researchers should publish our high-quality research in society journals to shape the future of science and scientific publishing landscape.

The Inaugural Mbio Junior Editorial Board—Lessons Learned And The Path Forward Toward Improving The Peer Review Process, Cynthia Ayefoumi Adinortey, Stephen K. Dolan, Sarah Doore, Rebeccah Lijek, Diana Priscila Pires, Wenqi Yu, Elizabeth B. Draganova, Lennart Schada Von Borzyskowski

Molecular Biosciences Faculty Publications

The inaugural Junior Editorial Board (JEB) of mBio consisted of 64 early-career researchers active from 2022 to 2023. The goal of the JEB was to train early-career researchers in the art of peer review under the guidance of experienced editors. JEB members gained hands-on experience in peer review by participating in modules detailing the publishing process through the lenses of the journal, editor, and reviewer. Ultimately, JEB members applied this new knowledge by reviewing mBio manuscripts. Here, we summarize the background, the mission, and the achievements of the first mBio JEB. We also include possible trajectories for the future editions …

Revolutionizing Our Understanding Of Specific Platelet-Pathogen Interactions, Hammodah Rawhi Hammodah Alfar

Theses and Dissertations--Molecular and Cellular Biochemistry

Aside from their classical role in maintaining hemostasis, platelets are considered first-line vascular guardians that influence both the innate and adaptive immune systems. This is mediated by either direct interactions with immune cells or through the release of pre-stored cytokines and chemokines upon interacting with pathogens such as viruses. While this establishes platelets as potential players in the response to pathogens, it remains unclear what platelets can do with pathogens and how important that is to immune responses, especially against viruses. Most systemic viremias, such as HIV-1, present with mild thrombocytopenia, which is mediated through several mechanisms such as a …

Multiple Variables Influence The Finely Calibrated Antioxidant Defenses Of Clostridioides Difficile, Erin B. Purcell

Chemistry & Biochemistry Faculty Publications

The obligate anaerobe Clostridioides difficile encodes multiple reductases to detoxify molecular oxygen and reactive oxygen species. Caulat and colleagues have characterized the activity and regulation of four such reductases (L. C. Caulat, A. Lotoux, M. C. Martins, N. Kint, et al., mBio 15:e01591-24, 2024, https://doi.org/10.1128/mbio.01591-24). Each proved critical for clostridial survival in a different range of oxygen concentrations; together, they ameliorate a broad range of oxidative stress levels. Moreover, two previously uncharacterized regulators were found to control reductase gene expression in response to oxidative stress. The genetic repressor Rex and the reductase FdpF are both sensitive to the NAP …

Role Of Autophagy-Related Genes In Lipid Transport For Efficient Replication Of Tombusviruses, Yuanrong Kang

Theses and Dissertations--Plant Pathology

Tombusviruses are positive-strand RNA viruses, which utilize numerous co-opted host factors and massive de-novo synthesized membrane resources to modify host membranes and form large viral replication organelles (VROs). Among plenty of host cellular processes, autophagy emerges as a potential membrane resource for VROs formation due to its ability to de-novo generate the double membrane structures, known as autophagosomes. Besides, as an important host defense pathway, autophagy is also a target for tombusviruses to prevent its antiviral activities. In this study, I identify the role of key autophagy related genes, Atg11, Atg8, and Atg2, which are involved in autophagosome formation, and …

Temporal Distribution Of Potential Waterborne Pathogens In Sequiota Spring, William J. Durstock

Graduate Theses/Dissertations

Waterborne pathogens from human fecal matter pose a significant health risk in karst environments, where domestic wastewater can easily be transferred to the shallow groundwater system via old, leaky septic tanks and damaged sewer lines. This study monitored fecal indicator bacteria (FIB) and potential pathogens in Sequiota Spring located in the karst region of southwest Missouri, using Microbial Source Tracking (MST) and Illumina DNA sequencing of bacterial 16S rRNA genes. MST identified high levels of human fecal indicator bacteria (HFIB) (up to 110,000 cells/L) in July 2020. By June 2022, HFIB levels had dropped significantly (55-fold reduction) after the City …

Understanding Cellular Dynamics: Investigating A Yeast-Two Hybrid Protein-Protein Interaction, Riok3:Cse1l; Also By Investigating Trogocytosis Of Cd4+ T Cells From Rhog-/- Mice, Brittnee N. Crane

Graduate Student Theses, Dissertations, & Professional Papers

Rift Valley fever virus (RVFV) is a negative-sense virus that was first described in 1930 when it was isolated from sheep during an outbreak. In the last 25 years there has been a spread in the geographical range into the Middle East. The most susceptible animals are cattle, goats, sheep, and camels. The most overt symptom of livestock infection is that infected pregnant animals experience spontaneous abortion. Humans are susceptible as well and symptoms range from mild febrile illness to liver necrosis, blindness, hemorrhagic fever, and death. An important player in the cellular innate response to RVFV infections is the …

Consequences Of Spatial Structure In Soil–Geomorphic Data On The Results Of Machine Learning Models, Daehyun Kim, Insang Song, Lorrayne Miralha, Daniel R. Hirmas, Ryan W. Mcewan, Tom G. Mueller, Pavel Samonil

Biology Faculty Publications

In this paper, we examined the degree to which inherent spatial structure in soil properties influences the outcomes of machine learning (ML) approaches to predicting soil spatial variability. We compared the performances of four ML algorithms (support vector machine, artificial neural network, random forest, and random forest for spatial data) against two non-ML algorithms (ordinary least squares regression and spatial filtering regression). None of the ML algorithms produced residuals that had lower mean values or were less autocorrelated over space compared with the non-ML approaches. We recommend the use of random forest when a soil variable of interest is weakly …

Synergetic Signaling Between The Chlamydia Secreted Effectors Tarp And Tmea Regulates Actin Kinetics And Efficient Entry, Matthew Romero

Theses & Dissertations

Chlamydia trachomatis is both the leading cause of non-congenital preventable blindness in developing nations and the leading source of bacterial sexually transmitted infections. As an obligate intracellular pathogen, Chlamydia has an absolute requirement on gaining entry into its host, which is accomplished by manipulating the host actin cytoskeleton to assemble engulfment structures that drive pathogen entry. In support of this, Chlamydia secretes the effectors TarP and TmeA via a type-III secretion system, whose respective signaling outputs operate synergistically to generate rapid actin kinetics and efficient pathogen engulfment. Rapid actin recruitment characteristic of invading Chlamydia is derived from a collaborative interaction …

Breaking Virulent: The Coincidental Evolution Of Virulence Factors In Bacteria., Rhiannon Emmanuelle Cecil

Electronic Theses and Dissertations

Understanding how innocuous organisms can evolve to be pathogenic to humans is of increasing global concern. Further, understanding how existing pathogens may evolved to be more virulent is also vital to our ability to provide healthcare to people afflicted with diseases that promote chronic bacterial infections, such as cystic fibrosis. With the rise of antibiotic resistance in both bacteria and fungi it is paramount that new therapeutics are identified. Understanding what mutations occur that result in increased virulence in microbes can potentially provide new targets for antimicrobial drugs to combat antibiotic resistance. The Coincidental Evolution Hypothesis is a fundamental hypothesis …

Exploring The Potential Of Tesla Valve For Filtering And Sorting Microscale Active Swimmers: A Computational Study, Ariel Rogers, Zhiyao He, Yong Wang

Physics Faculty Publications and Presentations

It is well-known that a Tesla valve allows fluids to flow unidirectionally without moving parts; however, how Tesla valves interact with active matters and the potential applications of Tesla valves in biology remain largely unexplored. Here, we present a computational study on the potential use of Tesla valves for filtering and sorting microscale active swimmers such as bacteria. We investigated the behavior of microscale swimmers passing through the Tesla valve at different linear and angular velocities using numerical simulations and quantified the diodicity of the Tesla valve for active swimmers. Our results demonstrate that the Tesla valve can effectively filter …

Short Chain Fatty Acid Combination Treatment Protects Against 6-Ohda And Wt Α-Synuclein Induced Decreases In Neurite Growth In In Vitro Models Of Parkinson’S Disease., Alex Morris

ORBioM (Open Research BioSciences Meeting)

Background

Parkinson’s disease (PD) is a neurodegenerative disorder characterized by dopaminergic neuron degeneration. This degeneration is partly driven by over expression of α-synuclein (α-syn) and development of α-syn aggregates known as Lewy bodies throughout the substantia nigra. As well as motor dysfunction, PD presents with several chronic gastrointestinal comorbidities, which cause a decline of gut microbial diversity and microbially derived short chain fatty acids (SCFAs). Recent in vivo studies have shown SCFAs to be neuroprotective in various degenerative disease states, suggesting that SCFAs may protect against dopaminergic degeneration.

Methods

Human neuroblastoma SH-SY5Y cells were used as a model of human …

The Pseudomonas Syringae Pv. Tomato Dc3000 Effector Hopd1 Interferes With Cellular Dynamics Associated With The Function Of The Plant Immune Protein Atnhr2b, Luis Francisco Marin-Ponce, Catalina Rodriguez-Puerto, Perla Rocha-Loyola, Clemencia M. Rojas

Entomology and Plant Pathology Faculty Publications and Presentations

The plant pathogenic bacterium Pseudomonas syringae pv. tomato DC3000 (Pst DC3000) causes disease in tomato, in the model plant Arabidopsis thaliana, and conditionally in Nicotiana benthamiana. The pathogenicity of Pst DC3000 is mostly due to bacterial virulence proteins, known as effectors, that are translocated into the plant cytoplasm through the type III secretion system (T3SS). Bacterial type III secreted effectors (T3SEs) target plants physiological processes and suppress defense responses to enable and support bacterial proliferation. The Pst DC3000 T3SE HopD1 interferes with plant defense responses by targeting the transcription factor NTL9. This work shows that HopD1 also targets the …

Dynamics And Inhibition Of Abc And Rnd Transporters Associated With Multidrug Resistances In Cancer And Pathogenic Bacteria, Hang Zhao

Biological Sciences Theses and Dissertations

The overexpression of efflux transporters is deemed to be one of the important mechanisms that contribute to Multidrug Resistance (MDR). In this dissertation, three transporters of significance were studied, the Breast Cancer Resistance Protein (BCRP/ABCG2) in a variety of cancer cells, the mtrCDE transporter from Neisseria gonorrhoeae, and the acrAB-tolC transporter from Escherichia coli. It is well known that the overexpression of BCRP in cancer cells results in these cells being resistant to the effects of many chemotherapeutics. This results in multidrug resistance for this cancer because of the fact that BCRP can transport many different types of …

Potent Bile Acid Microbial Metabolites Modulate Clostridium Perfringens Virulence, Tahrir Jatli Alenezi, Ying Fu, Bilal Alrubaye, Thamer Alanazi, Ayidh Almansour, Hong Wang, Xiaolun Sun

Poultry Science Faculty Publications and Presentations

Clostridium perfringens is a versatile pathogen, inducing diseases in the skin, intestine (such as chicken necrotic enteritis (NE)), and other organs. The classical sign of NE is the foul smell gas in the ballooned small intestine. We hypothesized that deoxycholic acid (DCA) reduced NE by inhibiting C. perfringens virulence signaling pathways. To evaluate the hypothesis, C. perfringens strains CP1 and wild-type (WT) HN13 and its mutants were cultured with different bile acids, including DCA and isoallolithocholic acid (isoalloLCA). Growth, hydrogen sulfide (H₂S) production, and virulence gene expression were measured. Notably, isoalloLCA was more potent in reducing growth, H …

Structural Insights Into The Cl-Par-4 Protein: Ionic Requirements, Conformational Transitions, And Interaction With Cisplatin, Krishna Kumar Raut

Chemistry & Biochemistry Theses & Dissertations

Cancer continues to be the leading global cause of death, with challenges in early diagnosis, drug resistance, non-specific drug targeting, and cancer recurrence and metastasis posing formidable obstacles in cancer therapy. In this context, Prostate Apoptosis Response-4 (Par-4), a pro-apoptotic tumor suppressor protein, emerged as a promising therapeutic target due to its ability to selectively induce apoptosis in cancer cells, thereby minimizing the drug-associated adverse effects. However, a comprehensive understanding of the structural features of Par-4, specifically the caspase-cleaved fragment (cl-Par-4), is crucial for therapeutic advancements.

This dissertation investigated the effects of various ions, both monovalent and divalent, on the …