Microbiology Commons^™

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 …

Interactions Of The Sars-Cov-2 Viral Genome 3’-Untranslated Region With Viral And Host Rnas, Caleb Frye, Mihaela Rita Mihailescu

Electronic Theses and Dissertations

This dissertation focuses on the characterization of RNA-RNA interactions within the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) genome and with host microRNAs. As the causative agent of coronavirus disease 2019 (COVID-19), SARS-CoV-2 has evolved rapidly since its appearance. This has warranted prompt characterization of the virus particularly of its single stranded RNA (ssRNA) genome. By using a combination of bioinformatics, biophysics, and/or biological assays, we analyzed the SARS-CoV-2 viral genomic RNA and uncovered interactions of genomic RNA with host RNAs, highlighting an underutilized method of targeting RNA viruses. We showed here that the conserved elements in the viral genomic …

Genome-Guided Isolation Of The Hyperthermophilic Aerobe Fervidibacter Sacchari Reveals Conserved Polysaccharide Metabolism In The Armatimonadota, Nancy O. Nou, Jonathan K. Covington, Dengxun Lai, Xavier Mayali, Cale O. Seymour, Juliet Johnston, Jian-Yu Jiao, Steffen Buessecker, Damon Mosier, Alise R. Muok, Nicole Torosian, Allison M. Cook, Ariane Briegel, Tanja Woyke, Emiley Eloe-Fadrosh, Nicole Shapiro, Scott G. Bryan, Savannah Sleezer, Joshua Dimapilis, Cristina Gonzalez, Lizett Gonzalez, Marlene Noriega, Matthias Hess, Ross P. Carlson, Lan Liu, Meng-Meng Li, Zheng-Han Lian, Siqii Zhu, Fan Liu, Xian Sun, Beile Gao, Ritesh Mewalal, Miranda Harmon-Smith, Ian K. Blaby, Jan-Fang Cheng, Peter K. Weber, Gabriela Grigorean, Wen-Jun Li, Anne E. Dekas, Jennifer E. Pett-Ridge, Jeremy A. Dodsworth, Marike Palmer, Brian P. Hedlund

Life Sciences Faculty Research

Few aerobic hyperthermophilic microorganisms degrade polysaccharides. Here, we describe the genome-enabled enrichment and optical tweezer-based isolation of an aerobic polysaccharide-degrading hyperthermophile, Fervidibacter sacchari, previously ascribed to candidate phylum Fervidibacteria. F. sacchari uses polysaccharides and monosaccharides for growth at 65–87.5 °C and expresses 191 carbohydrate-active enzymes (CAZymes) according to RNA-Seq and proteomics, including 31 with unusual glycoside hydrolase domains (GH109, GH177, GH179). Fluorescence in-situ hybridization and nanoscale secondary ion mass spectrometry confirmed rapid assimilation of 13C-starch in spring sediments. Purified GHs were optimally active at 80–100 °C on ten different polysaccharides. Finally, we propose reassigning Fervidibacteria as a class …

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 …

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 (

Exploring Biosignatures And Biogeochemical Processes In Lanzarote Lava Tubes: Implications For Martian Analog Research, Vera Palma, Ana Z. Miller, Francesco Sauro, Bogdan P. Onac, José M. De La Rosa, Sara Gutiérrez-Patricio, Beatriz Cubero, José A. Gonzalez-Perez, Jesus Martínez-Frías, A Teresa Caldeira

FRONTIERS UNBOUND: Exploring Extreme Environments

No abstract provided.

Exploring Pristine Microbial Ecosystems From The Uninhabited Volcanic Selvagens Islands, Pedro N. Jiménez-Morillo, Sara Gutiérrez-Patricio, Vera Palma, Ana Teresa Caldeira, Nicasio Tomás Jiménez-Morillo, Ana Z. Miller

FRONTIERS UNBOUND: Exploring Extreme Environments

No abstract provided.

Sequence Specificity Of Non-Structural Protein 15 From Sars-Cov-2, John Vincent Mcguire

Electronic Theses and Dissertations

The SARS-CoV-2 virus was recently able to cause a global pandemic, largely due to the asymptomatic period that occurs during initial infection. During this period, patients are infectious but do not exhibit symptoms, resulting in the unintentional spread of the virus. This occurs because the virus effectively avoids detection by the immune system during the early stages of infection, and as symptoms are the result of immune system activation, they never manifest. Non-structural Protein 15 (Nsp15) is one of the tools the virus uses to remain undetected, via its degradation of Pathogen-Associated Molecular Patterns (PAMPs) that would otherwise be recognized …

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 …

Investigation Of The Microbiome Of A Recirculating Aquaculture System (Ras) For Crassostrea Virginica Larvae, Isabelle Townsend

Master's Theses

Recirculating Aquaculture Systems (RAS) offer control over physicochemical and biological factors impacting aquaculture success. One understudied facet of RASs is the water microbiome. Oyster larval microbiomes are shaped by their aquatic microbiomes. Understanding the dynamics of and the factors shaping RAS microbiome may provide insights to how the microbiome can be a tool for optimizing larval production. This study’s goals were to investigate the microbiome stability of a RAS rearing oyster larvae across time and space, determine impacts of larval presence on the microbiome, and examine connections between larvae production outcomes and microbiome stability. Water samples were collected weekly from …

Assessment Of Tce And Chiral Pcb Dechlorination Rate, Congener Diversity, And Enantioselectivity In Town Creek, Sc, Usa Sediment Microcosms, Catherine P. Sumner

All Dissertations

Polychlorinated biphenyls (PCBs) and trichloroethene (TCE) are ubiquitous contaminants and are recognized as persistent organic pollutants due to their extreme chemical stability. PCBs were manufactured by chlorinating biphenyls that created 209 congeners with various structures, of which 19 are chiral and can exist as a pair of stable atropisomers. PCBs have been known to cause developmental and neurological toxicity in humans and wildlife; they can act as endocrine disrupters, carcinogens, and teratogens. Sangamo Weston Inc. was an industrial plant located near Town Creek in Pickens Country, South Carolina, that manufactured capacitors and used Aroclors 1016 and 1254 as dialectic fluids …

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 …

Group B Streptococcus Intestinal Barrier Disruption And The Protective Role Of Butyrate, Kristen Dominguez

USF Tampa Graduate Theses and Dissertations

Group B Streptococcus (Streptococcus agalactiae; GBS) is a leading cause of neonatal sepsis worldwide. Intrapartum antibiotics in GBS-colonized mothers significantly reduced the incidence of early-onset sepsis occurring in the first week of life; however, there are currently no prophylactic interventions for late-onset sepsis, occurring within the first 3 months of life. GBS is a pathobiont that primarily colonizes the gastrointestinal tract and can cross the intestinal barrier via both the paracellular and transcellular routes, causing invasive disease. Neonatal susceptibility to GBS intestinal translocation is mediated by inadequate epithelial barrier function and microbiome immaturity; however, the mechanisms by which GBS exploits …

Establishment Of Bacteroides In The Gut And Its Role In The Cystic Fibrosis Gut-Lung Axis, Rebecca A. Valls

Dartmouth College Ph.D Dissertations

In the quest to understand the complex interplay between the gut microbiota and cystic fibrosis (CF), a disease characterized by chronic upper respiratory complications and an exacerbated proinflammatory response, our lab engaged in a collaborative study with Dartmouth-Hitchcock Medical Center (DHMC) to characterize the gut microbiota of pediatric CF patients. Initial analyses established a connection between gut microbial composition and respiratory health, particularly highlighting a scarcity of Bacteroides species compared to healthy controls. In following investigations, we utilized random forest models to understand how stool microbiota may influence clinical outcomes of these pediatric CF patients, including: age, upper respiratory infections, …

Tetr Family Regulator, Farr, Influences Rot-Mediated Control Of Virulence Factor Expression In Staphylococcus Aureus, Julia C. Schumacher

USF Tampa Graduate Theses and Dissertations

Point-mutation variants of the TetR family regulator, FarR, have emerged across Staphylococcus aureus sequence types as conferring antibiotic and fatty acid resistance, particularly in Hospital-Associated Methicillin Resistant S. aureus (HA-MRSA) strains. FarR also exhibits an additional largely uncharacterized relationship to virulence factor production, seemingly through the global repressor of toxins—Rot, which functions to regulate S. aureus’ ability to colonize and persist in the host via a complex cascade of signaling. While Rot protein is post-transcriptionally regulated by the highly characterized Agr system, there is little known about its transcriptional regulation. Herein, we explored these dynamics by initially characterizing virulence phenotypes …

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 …

Characterizing The Role Of Pa5189 Of Pseudomonas Aeruginosa In Deletion And Overexpression Mutants, Seh Na Mellick

Theses/Capstones/Creative Projects

In the context of rising multidrug resistance in biofilm-forming pathogens like Pseudomonas aeruginosa, this study investigates the role of the understudied transcription factor PA5189 in antibiotic resistance and biofilm formation. PA5189 deletion and overexpression mutants were created in a parent P. aeruginosa strain using pEX18Tc-based recombinant suicide vectors, with genotypic verification of putative triparental conjugants achieved through restriction digestion and PCR. The study revealed that PA5189 overexpression significantly increases resistance to commonly used broad spectrum antibiotics such as ciprofloxacin and imipenem. Additionally, differential expression of PA5189 was found to notably affect biofilm formation, with variations contingent on the nutrient …

Pipecolic Acid And Novel Insights Into Cerebral Malaria, Akua E. Mensah

Theses and Dissertations

Cerebral malaria (CM), a severe manifestation of Plasmodium infection, prompts our investigation into the nuanced role of pipecolic acid in its pathophysiology. To unravel the molecular intricacies, we conducted in vitro lysine labeling techniques of mice infected with P. berghei ANKA parasites, and human P. falciparum grown in vitro, aiming to discern the impact of Plasmodium on pipecolic acid production. Previous observations indicated an elevation in pipecolic acid levels correlating with neurological decline in children with CM. In our study, confirming elevated pipecolic acid presence in the plasma and brain tissues of CM patients and the animal model of CM, …

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 …

Trna Anticodon Cleavage By Target-Activated Crispr-Cas13a Effector, Ishita Jain, Matvey Kolesnik, Konstantin Kuznedelov, Leonid Minakhin, Natalia Morozova, Anna Shiriaeva, Alexandr Kirillov, Sofia Medvedeva, Alexei Livenskyi, Laura Kazieva, Kira S Makarova, Eugene V Koonin, Sergei Borukhov, Konstantin Severinov, Ekaterina Semenova

Rowan-Virtua School of Osteopathic Medicine Departmental Research

Type VI CRISPR-Cas systems are among the few CRISPR varieties that target exclusively RNA. The CRISPR RNA–guided, sequence-specific binding of target RNAs, such as phage transcripts, activates the type VI effector, Cas13. Once activated, Cas13 causes collateral RNA cleavage, which induces bacterial cell dormancy, thus protecting the host population from the phage spread. We show here that the principal form of collateral RNA degradation elicited by Leptotrichia shahii Cas13a expressed in Escherichia coli cells is the cleavage of anticodons in a subset of transfer RNAs (tRNAs) with uridine-rich anticodons. This tRNA cleavage is accompanied by inhibition of protein synthesis, thus …

Targeting Mycobacterial Efflux System For Combating Anti-Microbial Resistance, Arathi Radhakrishnan, Raj Kishor Kapardar, Rajpal Srivastav

Research Symposium

Background: The drug resistance in the microbes is a serious concern in medicine. Along with intrinsic factors, extrinsic factors like unprescribed usage of drugs are the contributing factors. The drug tolerance has led to the emergence of superbugs. Mycobacterial species utilize an array of multidrug efflux mechanisms linked to intrinsic and acquired antibiotic resistance. Understanding molecular mechanisms regulating efflux could reveal new therapeutic targets and strategies. Our study is aimed to target regulators of efflux Mycobacterial transporter.

Methods: Using the reference mycobacterial strain, antibiotic sensitivity was first profiled by minimal inhibitory concentration assays across a panel of antimicrobials, followed by …

Borrelia Burgdorferi Plza Is A Cyclic-Di-Gmp Dependent Dna And Rna Binding Protein, Nerina Jusufovic, Andrew Krusenstjerna, Christina R. Savage, Timothy C. Saylor, Catherine A. Brissette, Wolfram Zückert, Paula J. Schlax, Md A. Motaleb, Brian Stevenson

Entomology Faculty Publications

The PilZ domain-containing protein, PlzA, is the only known cyclic di- GMP binding protein encoded by all Lyme disease spirochetes. PlzA has been implicated in the regulation of many borrelial processes, but the effector mechanism of PlzA was not previously known. Here, we report that PlzA can bind DNA and RNA and that nucleic acid binding requires c-di-GMP, with the affinity of PlzA for nucleic acids increasing as concentrations of c-di-GMP were increased. A mutant PlzA that is incapable of bind- ing c-di-GMP did not bind to any tested nucleic acids. We also determined that PlzA interacts predominantly with the …

Analysis Of Protein-Protein Interactions Between Legionella Pneumophilia Effectors, Briana Harness

Mahurin Honors College Capstone Experience/Thesis Projects

Legionella pneumophila an intracellular, opportunistic pathogen that is the causative agent of Legionnaires’ disease and Pontiac fever. A key component of Legionella’s pathogenicity is a series of effector proteins, which aid in the establishment of the Legionella-containing vacuole (LCV). The abundant library of effector proteins L. pneumophila has within its arsenal gives L. pneumophila the ability to infect several different hosts. The pathogenesis of L. pneumophila within various hosts depends on its ability to modulate the activity of its effector proteins through protein-protein interactions within effectors and eukaryotic host cell proteins. By understanding how L. pneumophila regulates its effectors, a …

Microbial Prevalence And Antibiotic Resistance Associated With Urban Food Production Systems, Nirosha Ruwani Amarasekara

Wayne State University Dissertations

Despite the increasing popularity of urban agriculture and farmers’ markets, there is a lack of scientific data on microbial prevalence and antibiotic resistance associated with this unique food production system. The overall goal of this research is to understand antibiotic resistance and microbial prevalence in soil and fresh produce associated with urban agriculture. Specifically, we aim to investigate ARG in association with resistance genes to metals and other compounds in urban agricultural soil as well as antibiotic resistome and Listeria contamination in fresh produce distributed in urban communities.

In the initial phase of this research, soil samples were collected from …

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 …

Iron–Sulfur Cluster Assembly Scaffold Protein Iscu Is Required For Activation Of Ferric Uptake Regulator (Fur) In Escherichia Coli, Huangen Ding

Faculty Publications

No abstract provided.