Bioindicators Of Mercury In Riverine Systems,
2024
Indiana State University
Bioindicators Of Mercury In Riverine Systems, Kathryn Mudica
All-Inclusive List of Electronic Theses and Dissertations
This study focuses on the bioaccumulation and biomagnification of mercury in freshwater food webs, with emphasis on bioindicators, such as macroinvertebrates, crayfish, and river otters. Despite regulatory efforts and advancements in monitoring, significant gaps remain in understanding mercury dynamics in freshwater systems—especially regarding its transport, methylation, and bioavailability across different ecosystems. To address these knowledge gaps, this study adopts a biocentric approach, emphasizing the role of living organisms in their environment. By utilizing macroinvertebrates, crayfish, and river otters as bioindicators, we aim to assess mercury bioavailability and distribution. These organisms provide varying temporal and spatial scales of mercury accumulation, offering …
Genome-Guided Isolation Of The Hyperthermophilic Aerobe Fervidibacter Sacchari Reveals Conserved Polysaccharide Metabolism In The Armatimonadota,
2024
University of Nevada, Las Vegas
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 …
Limits Of Longwood's Electron Microscope: A Study In Biological Imaging,
2024
Longwood University
Limits Of Longwood's Electron Microscope: A Study In Biological Imaging, Rachel Danzitz, Bjoern Ch. Ludwar
Fall Showcase for Research and Creative Inquiry
This study evaluates the imaging capabilities and limitations of the Hitachi TM4000II Plus Scanning Electron Microscope (SEM) and its Scanning Transmission adapter in biological imaging. A variety of specimens, including protozoans (e.g., Volvox and nematodes), bacteria (e.g., Magnetospirillum gryphiswaldense, Bacillus cereus, and Escherichia coli), tissue samples, and blood, were analyzed. While the SEM effectively imaged protozoans and bacteria, its ability to visualize viruses was deemed impractical. Despite claims of magnification up to 100,000x, clarity significantly decreased beyond 5,000x. The transmission adapter proved functional but challenging to operate consistently. The study highlights the microscope's limitations in producing high-clarity, …
Pilz Domain-Containing Proteins Regulate Motility In Acinetobacter Baumannii,
2024
East Tennessee State University
Pilz Domain-Containing Proteins Regulate Motility In Acinetobacter Baumannii, Gabriel Smith
Electronic Theses and Dissertations
Acinetobacter baumannii is an increasingly multidrug-resistant pathogen contributing to hospital-acquired infections, necessitating a greater understanding of how it interacts with its surroundings. Many bacteria utilize different methods of bacterial motility to move about and interact with these surroundings. A bacterial second messenger, cyclic diguanosine monophosphate (c-di-GMP), can regulate various motility factors that are potentially advantageous for survival in and adaptation to their environment. Concentrations of c-di-GMP are regulated by specific synthesizing and degrading enzymes. Controlled levels of c-di-GMP allow interaction between the c-di-GMP and its binding effectors that induce changes in bacterial phenotypes such as biofilm formation and motility. A …
Characterizing Enterobacter Cloacae Genetic Elements Responsible For Interactions With Candida Albicans,
2024
East Tennessee State University
Characterizing Enterobacter Cloacae Genetic Elements Responsible For Interactions With Candida Albicans, Abigail Suarez
Electronic Theses and Dissertations
Polymicrobial interactions are an important, yet understudied area of research. Candida albicans is the most common human fungal pathogen. The bacterial genus, Enterobacter, is a source of nosocomial acquired infections and increased drug resistance. Our lab has previously discovered that Enterobacter preferentially adheres to C. albicans hyphae. From an E. cloacae transposon library screen, six candidates displayed reduction in C. albicans attachment. These candidates were identified genetically and characterized for involvement in attachment to C. albicans. A fluorescent plasmid was introduced into E. cloacae to measure and observe adherence to C. albicans in planktonic and biofilm growth. In vivo …
The Physiological Significance Of Nitric Oxide Synthase In Staphylococci,
2024
University of Nebraska Medical Center
The Physiological Significance Of Nitric Oxide Synthase In Staphylococci, Ryan M. Singh
Theses & Dissertations
Staphylococci, particularly Staphylococcus epidermidis, are common causes of implant-associated infections that may result in notable morbidity and mortality. One of the ways the innate immune system attempts to combat these invading pathogens is via the respiratory burst, in which free radical species such as nitric oxide (NO•), toxic to bacterial respiration, are released in large quantities. Despite the toxicity of NO•, some bacteria, including staphylococci, encode an endogenous bacterial nitric oxide synthase (bNOS), whose physiological role has been unclear until now. In this dissertation, we demonstrate that S. epidermidis is able to overcome the toxicity …
Growth Of Methanogens On Kaolinite, A Clay That Has Been Identified On Mars,
2024
University of Arkansas, Fayetteville
Growth Of Methanogens On Kaolinite, A Clay That Has Been Identified On Mars, Hailey Littrell
Biological Sciences Undergraduate Honors Theses
Methanogens have been studied as a model for life on Mars for 28 years now in the Kral lab. The discovery of methane in the Martian atmosphere by ground-based and orbital observations as well as Curiosity Rover (Formisano, V. et al., Krasnopolsky, V.A. et al., Mumma, M.J. et al.) has added relevance to these types of studies. Methanogens were chosen due to their ability to live in harsh environments, very similar to the Martian terrain. In addition to methane in the atmosphere, phyllosilicate clays have also been identified. One of those clays is kaolinite. Kaolinite has been found to not …
Characterizing The Role Of Pa5189 Of Pseudomonas Aeruginosa In Deletion And Overexpression Mutants,
2024
University of Nebraska at Omaha
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 …
Managing Stress: A Study Of Stress Response Mechanisms In Mycobacteria,
2024
University of Texas at Arlington
Managing Stress: A Study Of Stress Response Mechanisms In Mycobacteria, Augusto C. Hunt Serracin
Biology Dissertations - Archive
Mycobacteria encompass many pathogenic species known to cause severe disease in humans. A well-known example is Mycobacterium tuberculosis (Mtb), the causative agent of the lung disease tuberculosis, which kills millions of humans worldwide yearly. Pathogenic mycobacteria like Mtb are challenging to treat because of their innate ability to adapt to environmental stress. Their unique cell physiology and conserved stress responses allow them to combat biological insults, regulate growth, and regulate genes involved in stress; all these responses increase tolerance to antibiotics. The current therapies to treat mycobacterial infections are lengthy and, at times, unsuccessful, partly due to antibiotic tolerance. A …
A New Model For Polar Growth In Mycobacteria: The Role Of Wag31 And Mmpl3 In Cell Wall Synthesis,
2024
University of Texas at Arlington
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 …
Iron–Sulfur Cluster Assembly Scaffold Protein Iscu Is Required For Activation Of Ferric Uptake Regulator (Fur) In Escherichia Coli,
2024
Louisiana State University
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.
Complete Genome Sequence Of Microbacterium Foliorum Phage Curie, A Podovirus Isolated From Soil In Spokane, Washington,
2024
Gonzaga University
Complete Genome Sequence Of Microbacterium Foliorum Phage Curie, A Podovirus Isolated From Soil In Spokane, Washington, Emma N. Horton, Kathryn T. Cook, Kyra G. Cronin, Avery T. Haag, Sierra M. Salter, Nicole A. Stojanovic, Zoe E. Fry, Brian M. Connolly, Rebekah F. Hare, Ann-Scott H. Ettinger, Marianne K. Poxleitner, Kirk Anders
Biology Faculty Scholarship
Bacteriophage Curie is a podovirus that infects Microbacterium foliorum. The Curie genome spans 16,810 bp, has 90 bp terminal inverted repeats, and includes 23 protein-coding genes. Its genome architecture resembles phage PineapplePizza and other phi29-like phages. Together, Curie and PineapplePizza form a new actinobacteriophage Cluster GI.
Characterization Of Serx: A Putative Periplasmic Binding Protein In A Selenate Respiring Bacteria,
2024
Colby College
Characterization Of Serx: A Putative Periplasmic Binding Protein In A Selenate Respiring Bacteria, Henry Jacques, Susan E. Childers
Honors Theses
A selenate respiring bacterium, Dechloromonas sp. A34, was isolated from a seleniferous mining site in southeastern Idaho. A34 was of interest due to its ability to respire up to 20 mM selenate, the highest concentration tested. The strain has been proposed to represent a new species of bacteria within the Dechloromonas genera, with the prospective name Dechloromonas selenatirespirans (manuscript in preparation). Our research presents characterization of a putative periplasmic binding protein found within an operon that contains genes encoding a putative selenate reductase. The gene, named serX (selenate reductase gene X), is 855 base pairs and encodes a putative …
Contributions Of The Replication Initiator Protein Dnaa To Physiology And Virulence Of The Lyme Disease Spirochete,
2024
University of Kentucky
Contributions Of The Replication Initiator Protein Dnaa To Physiology And Virulence Of The Lyme Disease Spirochete, Andrew Krusenstjerna
Theses and Dissertations--Microbiology, Immunology, and Molecular Genetics
Borrelia burgdorferi, the etiological agent of Lyme disease, is the most prevalent vector-borne disease in the United States. The spirochetal population is naturally maintained by consistently cycling between Ixodid ticks and small vertebrates. To survive within these diverse niches, B. burgdorferi has evolved a unique physiology and regulatory network to sense and respond to environmental fluxes. Replication is a hallmark of the Lyme spirochete’s enzootic life cycle, specifically at the nymphal tick-to-vertebrate interface. The mechanisms and regulatory schema for the basic cellular processes in B. burgdorferi, or indeed any member of the phylum spirochaetota, are largely unknown. The central hypothesis …
The Effect Of Nanoconfined Liquid Properties On The Water-Responsive Behavior Of Bacterial Cell Walls,
2024
CUNY City College
The Effect Of Nanoconfined Liquid Properties On The Water-Responsive Behavior Of Bacterial Cell Walls, Seungri Kim
Dissertations and Theses
Water-responsive (WR) materials have the ability to mechanically swell and shrink in response to changes in relative humidity (RH). These WR materials are used by many biological systems to perform essential tasks; for example, pinecones use WR materials to release their seeds in dry environments, and wheat awns open and close to propel seeds into the soil, driven by daily RH changes. The WR actuation of some biomaterials is extremely powerful, for example Bacillus subtilis cell walls display record-high actuation energy and power densities of 72 MJ m-3 and 9.1 MW m-3, surpassing those of all existing …
Examining The Role Of Microbial Communities In Soil Carbon Cycling Across Levels Of Complexity,
2024
West Virginia University
Examining The Role Of Microbial Communities In Soil Carbon Cycling Across Levels Of Complexity, Chansotheary Dang
Graduate Theses, Dissertations, and Problem Reports (ETD)
Microorganisms provide the foundation for many ecosystem processes and are important drivers of carbon and nutrient cycling. The advancement of next generation sequencing has allowed researchers to lift open the lid on the ‘black box’ in microbial ecology. While previously unculturable microbes can now be characterized with the 16S rRNA gene, answering ‘who’s there?’ is only part of the challenge. Hidden inside the ‘black box’ remains the question, ‘who’s doing what?’. Recent development in trait-based methods like quantitative stable isotope probing (qSIP) equipped microbial ecologists with the tool to connect taxon-specific traits to ecosystem processes. Despite the growing body of …
Effects Of Subchronic Oral Pfos Exposure Via Drinking Water On Gut Microbiota Composition,
2024
Missouri State University
Effects Of Subchronic Oral Pfos Exposure Via Drinking Water On Gut Microbiota Composition, Emma Ann Loder
Graduate Theses/Dissertations
Perfluorooctanesulfonic acid (PFOS) has been phased out of production in the United States, but because of its resistance to degradation and its persistence in the environment, PFOS can be found in drinking water across America. Oral exposure to PFOS has been linked to adverse developmental, immunological, hepatic, and endocrine health. Oral PFOS exposure may alter the gut microbiota and cause dysbiosis, which is implicated in the pathology of inflammatory diseases like Crohn’s disease, diabetes, and ulcerative colitis. The goal of the study was to investigate the effects of subchronic oral PFOS exposure on the composition of the gut microbiota. Adult …
Investigation Of L-Serine Synthesis And Transport As Stabilizing Feedback Mechanisms Within The Tsetse-Wigglesworthia Symbiosis,
2024
West Virginia University
Investigation Of L-Serine Synthesis And Transport As Stabilizing Feedback Mechanisms Within The Tsetse-Wigglesworthia Symbiosis, Ryan Phillips
Graduate Theses, Dissertations, and Problem Reports (ETD)
Tsetse flies (Glossina morsitans), which are the obligate vectors of Old-World trypanosomes (Trypanosoma spp.) that cause African trypanosomiasis, have a bacteriome that houses the intracellular endosymbiont Wigglesworthia glossinidia. The ancient coevolution of these species has led to the integration of Wigglesworthia metabolism into tsetse physiology and a subsequent reliance on nutrient exchange for maintaining the fitness of both partners. The establishment of this obligate mutualism has facilitated the emergence of feedback mechanisms that stabilize the symbiosis, such as that which involves the exchange of L-serine and B vitamins. The Gammaproteobacteria Wigglesworthia supplement B vitamins lacking …
Characterizing The Regulation Of Candida Albicans Hyphal Morphogenesis In The Context Of Host Macrophages,
2023
The University of Texas MD Anderson Cancer Center UTHealth Graduate School of Biomedical Sciences
Characterizing The Regulation Of Candida Albicans Hyphal Morphogenesis In The Context Of Host Macrophages, Hannah Wilson
Dissertations and Theses (Open Access)
Candida albicans is a commensal fungus that resides on the skin, mucosal surfaces, and in the gut of an estimated 80% of individuals. Though generally harmless, C. albicans is capable of causing uncomfortable mucosal infections as well as deadly disseminated infections depending on the immune status of the host. Although antifungal therapeutics exist, the mortality rate associated with disseminated disease still lingers around 50%. Further, C. albicans is the fourth most common cause of all bloodstream infections and continues to present as a major clinical issue with less than satisfactory treatment options. For this reason, it is imperative to understand …
What Is Microbial Dormancy?,
2023
Argonne National Laboratory
What Is Microbial Dormancy?, Mark D. Mcdonald, Carlos Owusu-Ansah, Jared B. Ellenbogen, Zachary D. Malone, Michael P. Ricketts, Steve E. Frolking, Jessica Gilman Ernakovich, Michael Ibba, Sarah C. Bagby, J. L. Weissman
Biology, Chemistry, and Environmental Sciences Faculty Articles and Research
Life can be stressful. One way to deal with stress is to simply wait it out. Microbes do this by entering a state of reduced activity and increased resistance commonly called ‘dormancy’. But what is dormancy? Different scientific disciplines emphasize distinct traits and phenotypic ranges in defining dormancy for their microbial species and system-specific questions of interest. Here, we propose a unified definition of microbial dormancy, using a broad framework to place earlier discipline-specific definitions in a new context. We then discuss how this new definition and framework may improve our ability to investigate dormancy using multi-omics tools. Finally, we …
