Life Sciences Commons^™

Difference In The Inhibitory Effects Of Violacein On Various Yeast Isolate Strains From The Hudson Valley Region, Lilah Dorothy Blaker

Senior Projects Spring 2023

Violacein is a purple pigmented compound produced by numerous bacterial species including Janthinobacterium lividum. Studies into violacein have found it to have a multitude of medicinal properties, from antifungal, antibiotic, to antitumor activity. Research has shown that violacein significantly inhibits both tumor and fungal growth and it has been shown to have higher cyotoxicity in pathogenic or cancerous cells than in healthy ones, giving it great potential as for use as a pharmaceutical drug in humans, alongside the fact that as a bacterial compound it’s easier and faster to produce than some other drugs. Violacein has also been shown to …

Death Of A Bacterium: Exploring The Inhibition Of Staphylococcus Aureus By Burkholderia Cenocepacia., Tiffany Brandt

Electronic Theses and Dissertations

Antimicrobial resistance is a phenomenon of increasing concern as antimicrobial overuse and misuse eliminate current therapeutic options, ushering society into a post-antimicrobial era. Antibiotic discovery and synthesis efforts are urgently needed to counter the increasing burden of antimicrobial resistance. Staphylococcus aureus is a causative agent of a variety of clinical manifestations including bacteremia, endocarditis, soft tissue infection, osteomyelitis, and device-related infections. S. aureus infection presents additional treatment challenges due to its capacity for biofilm formation, which is a mode of growth that confers protection from antibiotics and physical elimination, and the emergence of antibiotic resistant strains, including methicillin-resistant S. aureus …

Attempted Synthesis & Antibacterial Properties Of Apt-6k Against Ndm-1 K. Pneumoniae, Alec Bofetiado

Honors Theses

NDM-1 K. pneumoniae is a highly resistant bacterial organism that is capable of causing debilitating nosocomial infections in immunocompromised patients. Only "last-resort" antibiotics--such as colistin--work against this organism. Therefore, new antibiotics are needed to help fight against these types of infections. APT-6K is a novel compound that was demonstrated to be effective against MRSA with nanomolar concentrations in a prior study. Novel methods of APT-6K synthesis and its testing for antibiotic effects against NDM-1 K. pneumoniae were attempted in this research. APT-6K synthesis was unsuccessful. Commercially-prepared APT-6K also did not demonstrate growth inhibition against NDM-1 K. pneumoniae nor against a …

Mechanism Of Antibiotic Permeability Through The Gram-Negative Bacterial Envelope, Olaniyi Alegun

Theses and Dissertations--Chemistry

The outer membrane of Gram-negative bacteria (GN) makes them distinct among superbugs that are associated with the development of antibiotic resistance. The outer membrane, and inner membrane, separated by the periplasm, form a double-membrane barrier to the entry of antibiotics into the cell. Several studies have been conducted to examine the role of outer membrane modifications such as porins, lipopolysaccharides, and efflux pumps on antibiotic resistance. However, there is a paucity of knowledge on how antibiotics behave in the periplasm, to gain access into their target region. My thesis focuses on understanding the mechanism of antibiotic permeability through the cellular …

Changes In Antibiotic Resistance Of Soil Microbes During Human Decomposition, Victoria N. Beard

Chancellor’s Honors Program Projects

No abstract provided.

Development Of Small Molecule Antibiotics Against A Conserved Rna Gene Regulatory Element In Gram-Positive Bacteria, Ville Yrjö Petteri Väre

Legacy Theses & Dissertations (2009 - 2024)

Bacterial infections and the rise of antibiotic resistance, especially multidrug resistant strains, have generated a clear need for discovery of novel therapeutics. Most antibiotics in use today are derivatives of previous antibiotics to which resistance mechanisms already exist, and traditionally they have a single target: either a protein or rRNA. Gram-positive bacteria regulate the expression of several essential genes or operons using a mechanism called the T-box. The T-box is a structurally conserved riboswitch-like gene regulator in the 5’-untranslated region (UTR) of numerous essential genes of Gram-positive bacteria. T-boxes are stabilized by cognate, unacylated tRNA ligands, allowing the formation of …

A Possible Luxr Solo Type Regulator Of An Antibiotic-Like Compound From The Soil Bacterium Rhodococcus, Katelyn Sellick

Electronic Theses and Dissertations

Rhodococcus, a species of bacteria commonly found in the soil, is an under-explored producer of small bioactive compounds including siderophores, pigments and antibiotics. MTM3W5.2 is a strain of Rhodococcus that was previously discovered to produce an antibiotic-like compound that has inhibitory effects on other Rhodococcus strains, including the veterinary pathogen, R. equi. The biosynthetic gene cluster responsible for production of the antibiotic has been identified, and a small gene, BTZ20_3964 at the start of the operon is believed to be a luxR solo regulator of the gene cluster. The goal of this project was to determine this gene’s …

Antibiotic Drug Discovery Targeting Bacterial Metabolism, Miranda J. Wallace

Theses and Dissertations (ETD)

Over the last century, the use of antibiotics has enabled many advances in modern medicine, making life as we know it possible. In recent years, however, emerging bacterial resistance to virtually all major antibiotic classes has resulted in a worldwide increase in morbidity, mortality, and financial burden associated with drug resistant infections. The antimicrobial resistance crisis presents an urgent need for new antimicrobials with distinct mechanisms of action from existing drugs. The current pharmaceutical pipeline of new antibiotics is limited due to three obstacles: a lack of understanding of resistance mechanisms, a dearth of novel mechanisms of action among new …

Identification Of Inhibitors Of The Glutaminyl And Prolyl Trna Synthetases From Pseudomonas Aeruginosa, Yaritza Escamilla

Theses and Dissertations

Antibiotic resistance is a growing global threat and bacterial infections caused by antibiotic resistant bacteria have become increasingly difficult and expensive to treat with most current antibiotics. Pseudomonas aeruginosa is a Gram-negative opportunistic pathogen and a leading cause of nosocomial infections and is the leading cause of mortality in cystic fibrosis patients. Aminoacyl-tRNA synthetases (aaRSs) are a class of enzymes that catalyze the covalent attachment of amino acids to their cognate tRNAs during protein biosynthesis. The glutaminyl- tRNA synthetase from P. aeruginosa was over-expressed, enzymatically characterized and developed into a screening platform for the discovery of chemical compounds that inhibit …

Iron-Containing Nanoparticles For The Treatment Of Chrionic Biofilm Infections In Cystic Fibrosis, Leisha M. A. Martin

Nanoscience and Microsystems ETDs

Cystic fibrosis (CF) is the most common genetic disease resulting in the morbidity and mortality of Caucasian children and adults worldwide. Due to a genetic mutation resulting in malfunction of the Cystic Fibrosis Transmembrane Conductance Regulator (CFTR) protein, CF patients produce highly viscous mucus in their respiratory tract. This leads to impairment of the mucociliary clearance of inhaled microbes. In addition to reduced microbial clearance, anoxic environmental conditions in the lungs promote biofilm-mode growth of the pathogenic bacterial species Pseudomonas aeruginosa. Chronic infections of P. aeruginosa begin in early childhood and typically persist until respiratory failure and death result. The …

Identification Of Antibiotic Ge37468a From Pseudonocardia Symbionts Of Trachymyrmex Septentrionalis Ants, Krithika Rao

Scripps Senior Theses

In response to the growing rates of antibiotic resistance in human bacterial pathogens, this study explores the natural products involved in the defensive symbiosis between actinobacteria and fungus-growing ants to uncover new potential antibiotics. This study also seeks to understand the function of natural antibiotics in their ecological contexts, especially those involved in defensive symbioses. Defensive symbiosis can be a beneficial platform for discovering useful antibiotics, because antibiotics in these relationships must be able to selectively inhibit enemies without harming hosts, and are therefore likely more specific and less toxic. Pseudonocardia sp. associated with Trachymyrmex septentrionalis ants demonstrated antibiotic activity …

Impact Of Industrial Biocides On Bacterial Isolates From Hydraulic Fracturing Produced Water, Waad Ahmed Aljohani

Dissertations, Master's Theses and Master's Reports

Biocides are antimicrobial compounds that are designed to kill diverse groups of microbes in an untargeted fashion. Glutaraldehyde and DBNPA are commonly used to manage microbial growth in different industries. It is possible that biocide use may result in the development of bacterial resistance. However, resistance to DBNPA is believed to be limited under normal use conditions. We isolated a number of bacteria from produced water from a hydraulically fractured site in West Texas. We then tested the ability of these isolates to resist Glutaraldehyde and DBNPA. In this study, we found that these isolates have varying resistance to these …

Isolation, Sequencing, And Characterization Of Four Transmissible Antibiotic Resistance Plasmids Captured From Bacteria In Stream Sediments, Curtis J. Kapsak

Masters Theses, 2010-2019

Self-transmissible plasmids are key vectors in the transfer of resistance, catabolic, and other genes among bacteria native to environments such as streams and wetlands. The evolution of antibiotic resistance in particular is known to be powerfully affected by conjugative plasmid transfer due to the ease in which some plasmids can be horizontally transferred into a broad range of host bacteria and their ability to exchange mobile genetic elements that often contain antibiotic resistance genes.

In this study, we captured tetracycline resistance plasmids from stream sediments impacted by agricultural runoff. We selected for resistance plasmids using tetracycline, an antibiotic commonly used …

Antibiotic Resistant Bacteria In Water Environments In Louisville, Kentucky., Amy Priest

College of Arts & Sciences Senior Honors Theses

Antibiotic resistant bacterial strains are an increasing problem, particularly in clinical health care settings. As a result, bacterial infections are becoming increasingly challenging to treat with more cases becoming life threatening. Aquatic environments facilitate microbial diversity and the transfer of genetic elements and thus may serve as a reservoir for antibiotic resistant microbes. Human misuse of antibiotics may further facilitate the spread of resistance in water environments. With little known about the bacteria communities in local water environments, this study aimed to learn more about these populations through the following aims: 1) identify the microbial community composition from water environments …

Trends In Antibiotic Resistance And Correlations Of Antibiotic Use And Antibiotic Resistance In A Small Hospital In El Paso, Texas 2013-2015, Christopher Olivas

Open Access Theses & Dissertations

Antibiotic resistance is a serious public health threat, primarily, resulting from the excess and inappropriate use of antibiotics. Antibiotic resistance and antibiotic consumption trends may differ along the U.S-Mexico border from the rest of the U.S. due to geographical and cultural differences unique to the border region. The objectives of this study were: 1.) To examine the trends in antibiotic resistance among E. coli, ESBL producing E. coli, P. aeruginosa, S. aureus, and MRSA over a 3-year period (2013, 2014, 2015) in a U.S.-Mexico border area hospital; 2.) To examine the trends in antibiotic consumption among aztreonam, cefazolin, cefepime, ceftriaxone, …

An Interdisciplinary Approach To The Target Elucidation Of Novel Antibiotic 31g12, Larissa A. Walker

Graduate Student Theses, Dissertations, & Professional Papers

Staphylococcus aureus is a Gram-positive bacterial pathogen responsible for nosocomial and community-acquired infections that can quickly acquire antibiotic resistance. We have identified a novel triazole antimicrobial 31G12 based on the natural product core of nonactin isolated from the fermentation of Streptomyces griseus, that is active against many Gram-positive bacteria as well as antibiotic resistant methicillin-resistant S. aureus and vancomycin-resistant Enterococcus. The synthesis and characterization indicate that 31G12 exists as a mixture of two rotamers at room temperature and displays bacteriostatic activity against S. aureus with moderate mammalian cell toxicity. We have currently identified potential protein targets of 31G12 in …

Evaluation Of An Essential Oil Blend And A Novel Soybean Variety As Alternatives To Preventative Antibiotic Use In Monogastrics, Samantha Tauer

Electronic Theses and Dissertations

Increasing consumer pressure to minimize antibiotic use and the implementation of the Veterinary Feed Directive in 2017 has increased research on alternatives to preventative antibiotics. This thesis focuses on evaluation of Ralco’s Microfused™ Essential Oils (MEO) fed to broilers and soybean meal from low allergenicity soybeans fed to weaned pigs and their potential use as alternatives to antibiotics. Essential oils are known to have antimicrobial, antioxidant, antiparasitic, and digestive stimulant effects. Low allergenicity (LA) soybeans were bred to contain significantly lower concentrations of the following anti-nutritional factors and allergenic proteins: Kunitz trypsin inhibitor, soybean agglutinin (lectin), and P34 (Gly m …

A Novel Approach To The Discovery Of Natural Products From Actinobacteria, Rahmy Tawfik

USF Tampa Graduate Theses and Dissertations

Actinobacteria, primarily the genus Streptomyces, have led to the development of a number of antibiotics, which result from their secondary metabolites or modified derivatives. Secondary metabolite production can result from competition with neighboring microbes in an effort to disrupt growth, aiding in the competition for vital nutrients in impoverished conditions. Such secondary metabolites have the potential to affect a plethora of cellular functions in target cells, including, cell wall development, protein synthesis, protein function and fatty acid synthesis/metabolism. Due to the pandemic spread of antibiotic resistant bacteria, it is imperative to continue the search for new therapeutic agents …

Antibiotic Resistance Genes In Minnesota Soil Bacteria From Areas Of High And Low Ferric Iron, Gunner L. Drossel, Presley Martin Phd

Departmental Honors Projects

Naturally-occurring antibiotic resistance genes in soil bacteria represent a potentially important reservoir of genes that could contribute to antibiotic resistance of human pathogens. It has been reported that over 40 genes in bacterial genomes are controlled by concentrations of ferric iron. We examined the effect of soil metal content on the level of resistance to two antibiotics, ampicillin (Amp) and tetracycline (Tet), and the presence of multiple genes that code for efflux pump-mediated resistance. These pumps act to export toxins (e.g. heavy metals and antibiotics, perhaps). Because of this, growth in heavy metal-contaminated soils might select for antibiotic resistance. Ninety-six …

Effects Of Antibiotic Treatment On The Expression Of Hepatic And Intestinal Cytochrome P450, Bruno Pereira De Carvalho

Legacy Theses & Dissertations (2009 - 2024)

Expression of metabolic enzymes Cytochrome P450 (CYP) is highly affected by drugs, diseases, age and gender. The Intestinal microflora has been suggested to play a role in regulating CYP expression and antibiotic treatments would lead to changes in level and composition of microbiota in mouse gut. This study aims to analyze CYP expression changes in the liver and small intestine resulted from the reduction of intestinal microflora by antibiotics. Impacts on bile acid signaling were also analyzed for a better comprehension of the mechanisms involved in this modulation. Female C57BL/6J mice (9- to 13-week old) were treated with ampicillin (AMP) …

Antibiotic Resistant Bacteria In Natural Environments Within Kentucky., Steve Tran

College of Arts & Sciences Senior Honors Theses

Rates of antibiotic resistance in bacteria are rapidly rising; this is, in part, due to overuse of antibiotics resulting in a great burden on the U.S. healthcare system. With the rise of resistant bacteria, a large-scale outbreak of antibiotic resistant bacterial infections may also occur. Research on developing antibiotics has also decreased. Thus healthcare is at a great disadvantage in the arms race against bacteria. The environmental reservoirs of antibiotic resistance are currently being explored in Kentucky, in which bacteria have been collected from a broad spectrum of natural environments to analyze their antibiotic resistant capabilities and their interactions with …

Examination Of Klebsiella Pneumoniae 5'-Methylthioadenosine/S-Adenosylhomocysteine Nucleosidase And 5-Methylthioribose Kinase, Jason Alan Stonick

Boise State University Theses and Dissertations

Klebsiella pneumoniae is an opportunistic bacterial pathogen that is emerging as a major global threat as an infectious agent. This organism, along with many other pathogens, possesses a broad suite of antibiotic resistances that can make treatment exceedingly difficult. As such, the impetus for creating novel antibiotics is at an all-time high despite the fact that pharmaceutical investment into drug development is at an all-time low. S-adenosylmethionine (SAM) is a universally utilized metabolite involved in a wide array of biosynthetic processes, and whose products are catabolized by a different set of enzymes in mammals than used by many bacteria, protozoa, …

Super-Killers: Environmental Isolates That Antagonize Pathogenic Vibrio, Abigail Joy

Honors Projects

Vibrio are members of a bacterial group that thrive in diverse aquatic environments including on the surface of aquatic animals, free-living in the water column, and in association with suspended particles. The total Vibrio counts in the coastal ocean ranges from 10³-10⁵ per milliliter of water depending on seasons and water temperature. Although many different species of Vibrio persist in the water column, pathogenic strains, such as Vibrio cholerae and Vibrio parahaemolyticus are absent or rare in marine environments. We hypothesize that the low abundance of these pathogenic species may be due to interspecific competition among environmental …

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 …

Sub-Inhibitory Antibiotics Enhance Virulence, Persistence, And Pathogenesis Of Uropathogens, Lee W. Goneau

Electronic Thesis and Dissertation Repository

In addition to their bactericidal effects, antibiotics are potent signal mediators at sub-inhibitory levels in the environment. The ability to modulate community structure in this niche raises concerns over their capacity to influence pathogenesis in patients during antibiotic therapy. This concept forms the basis of this thesis, and is explored using models of prophylactic therapy for recurrent urinary tract infection (UTI) management.

Sub-inhibitory ciprofloxacin, ampicillin, and gentamicin were found to augment virulence in vitro, increasing adherence and urothelial cell invasion in uropathogenic Escherichia coli (UPEC) and Staphylococcus saprophyticus. In addition, biofilm formation was increased, and swarming motility decreased. …

Assessment Of Antimicrobial Resistance In Pathogens Responsible For Causing Bovine Mastitis In Kentucky, Erica Denise West

Online Theses and Dissertations

Bovine mastitis is most significant disease seen in dairy farms worldwide, resulting in the largest profit loss of any other disease affecting dairy cows. The aim of this thesis was to determine the predominant species responsible for bovine mastitis in a subset of ten Kentucky dairy herds, and to assess the presence of antibiotic resistance in these pathogens. In this study, 308 milk samples were obtained from cow's selected based on their recent somatic cell count. Samples positive for growth were identified using the gram stain and various biochemical tests. After identification, resistance to 11 antimicrobial agents was assessed using …

Isolation Of A Rhodococcus Soil Bacterium That Produces A Strong Antibacterial Compound., Ralitsa Bogomilova Borisova

Electronic Theses and Dissertations

Rhodococci are notable for their ability to degrade a variety of natural and xenobiotic compounds. Recently, interest in Rhodococcus has increased due to the discovery of a large number of genes for secondary metabolism. Only a few secondary metabolites have been characterized from the rhodococci (including 3 recently described antibiotics). Twenty-four new Rhodococcus strains were isolated from soils in East Tennessee using acetonitrile enrichment culturing and identified using 16S rRNA analysis. Forty-seven Rhodococcus strains were screened for antibiotic production using a growth inhibition assay. One strain, MTM3W5.2, had 90% similarity to the Rhodococcus opacus 16S rRNA gene sequence and produced …

The Efficacy Of Antibiotic Residue Screening Tests For The Detection Of Natural Antimicrobials In Milk, Stacey L. O'Donnell

Master's Theses

No abstract provided.

Discovery And Characterization Of An Antibiotic From The Soil Bacterium Bacillus Sp., Thomas S. Barber

Electronic Theses and Dissertations

Many important antibiotics have become nearly obsolete due to the rise of antibiotic resistant pathogens. Rhodococcus, an actinomycete related to the prolific antibiotic producing genus Streptomyces, harbors over 30 genes for secondary metabolism that could be involved in antibiotic production. Several antibiotics have already been reported for Rhodococcus, suggesting the genus may be a good source for new inhibitory compounds. Fifty four soil bacteria were isolated using enrichment culture techniques (including 37 Rhodococcus) and screened for antibiotic producers. BTHX2, a species of Bacillus was found to have activity against Micrococcus luteus and Rhodococcus erythropolis. BTHX2 …

Latex Of Sciadopitys Verticillata (Thunb.) Siebold And Zuccarini: Antibiotic Properties, Phytochemistry, And Inhibition Of Adventitious Rooting Of Stem Cuttings., David Ira Yates

Electronic Theses and Dissertations

Sciadopitys verticillata was subjected to three propagation treatments designed to inhibit coagulation of its latex-like sap at the cut ends of the stem cuttings. Twenty-four hour soaking in water prior to rooting hormone application significantly enhanced production of adventitious roots. Old wood stem cuttings from shade-grown trees rooted at higher proportions than stem cuttings collected from sun-grown trees. Height, age, and place of origin of the source trees were not important factors in successful rooting. Antibacterial activity against some human pathogens and soil bacterial species was detected in latex application trials but the antibiotic activity was not related to the …