Other Microbiology Commons^™

Role Of The C-Terminus Of The Catalytic Subunit Of Translesion Synthesis Polymerase Ζ (Zeta) In Uv-Induced Mutagensis, Hollie M. Siebler

Theses & Dissertations

Cellular DNA is under constant attack by endogenous and exogenous DNA damaging agents that threaten genome integrity. Unrepaired DNA lesions often stall replicative DNA polymerases and are bypassed by translesion synthesis (TLS) to prevent replication fork collapse. TLS mechanisms are lesion- and species-specific, with prominent roles of specialized DNA polymerases with relaxed active sites. After incorporation of nucleotide(s) across from the lesion, the distorted primer termini are typically extended by DNA polymerase ζ (Pol ζ). As a result, Pol ζ is responsible for most DNA damage-induced mutations. Mechanisms of sequential polymerase switches and regulation of Pol ζ access to DNA …

Characterization Of The Replication Of Coxsackievirus B3 With A Mutationally Disrupted Cre(2c) And The Use Of Creatinine-Hydrochloride As An Antibacterial Agent, Shane E. Smithee

Theses & Dissertations

Following natural or experimental infection, and in cell culture, coxsackie B virus (CVB) RNA can persist for weeks in the absence of CPE yet with detectable viral RNA. Earlier studies in our laboratory demonstrated that this persistence produced viral RNA with up to 49 nucleotide deletions at the 5’ genomic terminus, partially degrading the cloverleaf (or domain I), an RNA structure that is required for efficient viral replication. A cis-acting replication element (CRE) in the 2C protein coding region [CRE(2C)] templates the addition of two uridine residues to the virus-encoded RNA replication primer, VPg, prior to genomic replication. Because …

How Many Particles Are Present In The Air? Bioaerosol Detection Using An Air Particle Counter, Angie Pamela Rivera, Parag Vaishampayan

STAR Program Research Presentations

Relative cleanliness in terms of particle abundance in spacecraft assembly facilities is determined by particle counts carried out in clean rooms during resting conditions. Particle counters assess total particles and particle size distribution, but do not distinguish inert particles from biological particles, which may include bacterial spores that are resistant to standard cleanroom sterilization procedures. Current cleanroom certifications do not fully assess the effects of human presence on spacecraft contamination since humans are known symbionts to enumerate microorganisms and assessments are performed at rest when there is no human presence. In this study, contamination risks and bioburden in spacecraft assembly …

Identification Of Genes Required To Synthesize An Antibiotic-Like Compound From The Soil Bacterium Rhodococcus Sp. Mtm3w5.2, Amber L. Ward

Electronic Theses and Dissertations

Rhodococcus is a soil bacterium, member of the Actinobacteria, and a close relative of the prolific small molecule producer Streptomyces. Recent interest in Rhodococcus as an under investigated source of possible bioactive secondary metabolites is sparked by the discovery of many polyketide synthase and non-ribosomal peptide synthetase genes of unknown function from sequenced Rhodococcus genomes. Rhodococcus species strain MTM3W5.2 was recently shown to produce a strong inhibitory compound with activity against most strains of Rhodococcus and closely related genera. A goal of this investigation is to discover the gene(s) required to synthesize this inhibitory molecule. The engineered Rhodococcus …

Towards Bioregenerative Life Support For Extended Human Exploration: Experiment Development For Testing The Fitness Of Algae In Space, Audrey Fry, R. Craig Everroad, Jessica E. Koehne, Thomas E. Murphy, Brad M. Bebout

STAR Program Research Presentations

Microbes such as algae and bacteria are promising candidates for supporting extended human space travel, as they are robust sources of food, fuel, waste cycling, and oxygen production. Growing microbes on membranes reduces the mass and water demands of a bioreactor system, both of which are important considerations in space travel. The European Modular Cultivation System (EMCS) on the International Space Station (ISS) provides an ideal opportunity to test the effects of microgravity and other aspects of the space environment on algal growth on membranes. This project aims to find optimal growing conditions and measurement technologies that conform to the …

Prokaryotic Diversity In The Rhizosphere Of Organic, Intensive, And Transitional Coffee Farms In Brazil, Adam Caldwell, Livia Silva, Cynthia Da Silva, Cleber Ouverney

Faculty Publications, Biological Sciences

Despite a continuous rise in consumption of coffee over the past 60 years and recent studies showing positive benefits linked to human health, intensive coffee farming practices have been associated with environmental damage, risks to human health, and reductions in biodiversity. In contrast, organic farming has become an increasingly popular alternative, with both environmental and health benefits. This study aimed to characterize and determine the differences in the prokaryotic soil microbiology of three Brazilian coffee farms: one practicing intensive farming, one practicing organic farming, and one undergoing a transition from intensive to organic practices. Soil samples were collected from 20 …

Cave Cyanobacteria Showing Antibacterial Activity, Vasiliki Lamprinou, Kyriaki Tryfinopoulou, Emmanuel N. Velonakis, Alkiviadis Vatopoulos, Smaragdi Antonopoulou, Elizabeth Fragopoulou, Adriani Pantazidou, Athena Economou-Amilli

International Journal of Speleology

Cave Cyanobacteria - thriving in an ‘extreme’ environment with interesting species biodiversity - are supposed to be a potential source of bioactive compounds. Lipid extracts from pure cultures of two recently established Cyanobacteria from Greek caves, Toxopsis calypsus and Phormidium melanochroun, were used for antibacterial screening against human pathogenic bacteria (reference and clinical isolates). Antimicrobial Susceptibility testing for both taxa was carried out using the disc-diffusion (Kirby Bauer) method, while preliminary data applying the standard broth microdilution method for the determination of the Minimal Inhibitory Concentration (MIC) are given only for T. calypsus. Antibacterial activity was demonstrated against the …

Comparison Of The Antibacterial, Colloidal, And Hemolytic Properties Of Novel Triple-Headed, Triscationic Amphiphiles, Tara Gallagher

Masters Theses, 2010-2019

Antibiotic resistant bacteria were first reported in the 1940s, several years after the clinical introduction of penicillin. Since then, antibiotic resistance has contributed to increasing bacterial infections, mortality rates, and treatment costs. One promising alternative to traditional antibiotics is the development and use of amphiphiles, compounds with at least one hydrophilic head group and one hydrophobic tail. Three novel series of triple-headed amphiphiles with variations in the third head group composition, tail length and number of tails (one or two) were synthesized. Isothermal titration calorimetry was used to determine the critical micelle concentration – the concentration at which amphiphiles aggregate …

Identification Of Transcription Factors Gzf3, Rfx1, Orf19.3928 As Being Implicated In Candida-Bacterial Interactions., Joni Watson

Undergraduate Honors Theses

Candida albicans is an opportunistic pathogen that is present in the normal flora in a majority of individuals. One key factor in C. albicans virulence is the ability to change its morphology from yeast to an elongated or hyphal form. The regulation of this morphogenesis relies in part upon quorum sensing (QS) molecules. C. albicans often exists as part of a mixed culture alongside other microbes and is influenced by their presence as well as the presence of QS molecules that they produce. In this study, a library of diploid homozygous transcriptional regulator knockout (TRKO) mutants were screened to identify …

Exploring The Physiological Role Of Vibrio Fischeri Pepn, Sally L. Cello

Master's Theses

The primary contributor to Vibrio fischeri aminopeptidase activity is aminopeptidase N, PepN. Colonization assays revealed the pepN mutant strain to be deficient at forming dense aggregates and populating the host’s light organ compared to wildtype within the first 12 hours of colonization; however the mutant competed normally at 24 hours. To address the role of PepN in colonization initiation and establish additional phenotypes for the pepN mutant strain, stress response and other physiological assays were employed. Marked differences were found between pepN mutant and wildtype strain in response to salinity, acidity, and antibiotic tolerance. This study has provided a foundation …

Role Of Extracytoplasmic Rna Polymerase Sigma 70 Factor, Pg0214, In The Survival Of Porphyromonas Gingivalis And In Adaptation To Environmental Stress., David M. Smith

Theses and Dissertations

Porphyromonas gingivalis, a gram-negative anaerobic, pathogenic bacterium is a major etiological agent in the initiation and progression of periodontal disease. Due to the ever-changing environment of the oral cavity, inhabitants like Porphyromonas gingivalis must possess the ability to adapt to changes in environmental conditions like pH, temperature, oxygen tension, and metal concentration. P. gingivalis should therefore have an efficient regulatory system in order to adapt and survive in the oral cavity. This response adaptation occurs at the transcriptional level, which involves alternative sigma factors. Extracytoplasmic function sigma (ECF-s) factors are the largest group of alternative sigma factors that play …

Efficacy Of Ultraviolet Radiation To Control Lactic Acid Bacteria In Wine Must, Brian D. Williams

All Master's Theses

The use of shortwave ultraviolet (UV_c) radiation to control lactic acid bacteria (LAB) in wine production was studied. A simulated wine sterilizer was built using a commercially sourced ultraviolet (UV) sterilizer commonly used in aquariums and ponds. After growing cultures in test tubes, samples of five different species of LAB were introduced into white grape juice adjusted for brix and pH to match that of wine must commonly found in the Yakima Valley American Viticultural Area. The mixture was then agitated and allowed time to evenly distribute the bacteria throughout the juice. The juice was sent through the …

Mechanism Of Inactivation By High Voltage Atmospheric Cold Plasma Differs Between Escherichia Coli And Staphylococcus Aureus, Lu Han, Sonal Patil, Daniela Boehm, Vladimir Milosavljević, Patrick J. Cullen, Paula Bourke

Articles

Atmospheric cold plasma (ACP) is a promising non-thermal technology effective against a wide range of pathogenic microorganisms. Reactive oxygen species (ROS) play a crucial inactivation role when air or other oxygen containing gases are used. With strong oxidative stress, cells can be damaged by lipid peroxidation, enzyme inactivation and DNA cleavage. Identifying ROS and understanding their role is important to advance ACP applications to a range of complex microbiological issues. In this study, the inactivation efficacy of in-package, high voltage (80 kV_RMS) ACP (HVACP) and the role of intracellular ROS were investigated. Two mechanisms of inactivation were observed …

Quantitative Analysis And Imaging-Based Insights Into The Characteristics And Mechanisms Of Yeast Pattern Formation, Lin Chen

Dissertations and Theses (Open Access)

Biofilm formation is a common lifestyle adapted by bacteria and fungi in response to various environmental stresses. Bacterial and fungal biofilms adhering to medical devices convey resistance to antibiotics or biocides, causing high rates of clinical infections. Microorganisms are protected from harsh environmental conditions by reduced stress penetration through the complex biofilm architecture with distinct patterns. Although the molecular regulations of surface patterning have been well characterized in bacteria, the mechanisms underlying the complex pattern formation in eukaryotic biofilms remain unclear.

This dissertation aims to investigate the salient features of robust colony expansion in yeast biofilms and the processes driving …

Development Of A Molecular Gram-Stain Assay For The Diagnosis Of Blood Stream Infections Associated With Sepsis, Douglas Bryan Litwin

Dissertations and Theses (Open Access)

Sepsis is a serious medical condition resulting from the severe dysregulation of the immune response that is generally triggered by infection. It affects more than 1.1 million Americans, has an average mortality rate of 30%, and is estimated to cost $24.3 billion annually. Currently, blood culture followed by Gram-stain analysis is the gold standard for diagnosing bacterial infections associated with sepsis. This method generates a high rate of false negative results and, in general, requires 20 to 48 hr to provide results. Both of these problems are related to the requirement that the bacterial pathogens grow under defined laboratory conditions. …

The Show Cave Of Diros Vs. Wild Caves Of Peloponnese, Greece - Distribution Patterns Of Cyanobacteria, Vasiliki Lamprinou, Daniel B. Danielidis, Adriani Pantazidou, Alexandra Oikonomou, Athena Economou-Amilli

International Journal of Speleology

The karst cave ‘Vlychada’of Diros, one of the oldest show caves in Peloponnese, sustains extended phototrophic biofilms on various substrata – on rocks inside the cave including speleothems, and especially near the artificial lighting installation (‘Lampenflora’). After a survey of the main abiotic parameters (Photosynthetically Active Radiation -PAR, Temperature -T, Relative Humidity -RH, Carbon Dioxide -CO₂) three clusters of sampling sites were revealed according to Principal Component Analysis (PCA): i) the water gallery section predominately influenced by CO₂, ii) the dry passages influenced by RH and PAR, and iii) the area by the cave exit at …

Fty720 (Fingolimod) Provides Insight Into The Molecular Mechanisms Of Multiple Sclerosis, Madelyn Elizabeth Crawford

Pursuit - The Journal of Undergraduate Research at The University of Tennessee

Multiple sclerosis (MS) is a neurodegenerative disorder caused by a prolonged immune- mediated inflammatory response that targets myelin. Nearly all of the drugs approved for the treatment of MS are general immunosuppressants or only function in symptom management. The oral medication fingolimod, however, is reported to have direct therapeutic effects on cells of the central nervous system in addition to immunomodulatory functions. Fingolimod is known to interact with sphingosine-1-phosphate (S1P) receptors, and the most widely- accepted theory for its mechanism of action is functional antagonism of the receptor. This review examines significant neuromodulatory effects achieved by functional antagonism of the …

Characterizing The Response Of Multidrug-Resistant Klebsiella Pneumoniae Species To The Application Of A Phage Cocktail, Steven Liu

Symposium

Project Summary: The application of bacteriophages to treat bacterial infections is known as phage therapy, which takes advantage of bacteriophage’s natural ability to infect and lyse bacterial hosts. Phages have been shaped by billions of years of evolution to be highly specialized deliverers of bactericidal agents to the cytoplasm of their target bacteria. Ever since discovery of bacteriophages in 1915, phage therapy was recognized as a potentially powerful tool for eliminating bacterial infections. The effectiveness of phage therapy can be increased by creating a mixture of multiple phages to target a wider variety of bacterial strains. Furthermore, phage therapy has …

Chemical Profiling And Biological Activity Of Two Tunicate-Associated Marine Bacteria, Lyubina Yankova

Honors Scholar Theses

Marine natural products have recently been an increasingly abundant source of novel antibiotics. Given that there is an increasing resistance to current drug therapies, finding new sources such as marine natural products is essential. Tunicate-associated marine bacteria can be a significant source of antibacterial compounds. Two tunicates of the species Eudistoma were collected from Portobelo National Park on the Salmedina Reef of Panama in the Caribbean Sea. Bacteria associated with the tunicate were isolated, cultured, extracted, and fractionated. Fractions were tested against an array of clinically relevant bacterial pathogens in the BioMAP assay. Two fractions MB0086E and MB0088E demonstrated activity …

Characterization Of A Putative Cephalotoxin From The Hemocytes Of Euprymna Scolopes, Jessie E. Scott

University Scholar Projects

Many organisms have beneficial microbial symbionts, and complex interactions between the immune system and the bacteria must occur to allow these symbioses to persist. The host immune system must recognize and preferentially tolerate the beneficial microorganisms, while simultaneously eliminating harmful pathogens. The Hawaiian bobtail squid, Euprymna scolopes, is a model organism for host-microbe interactions because of the unique light organ symbiosis. Hemocytes, the squid’s primary immune cell, infiltrate and patrol the light organ and continuously interact with the symbiont Vibrio fischeri. Using this model, several innate immunity genes have been shown to be differentially expressed in the hemocytes …