Bacteriology Commons^™

Analysis Of The Atypical Temperature Dependence And Conformational Changes During Turnover Of A Lactobacillus Chlorogenic Acid Esterase, Nathaniel Carl, Yianni Tsigaris, Dan Ji, Nora K. Anpree, Kellie K. Omori, Cedric P. Owens

Biology, Chemistry, and Environmental Sciences Faculty Articles and Research

Many bacterial chlorogenic acid esterases (ChlEs) exhibit atypical temperature behavior, featuring activities that barely change with temperature and activity maxima that fall below the thermal denaturation point. This work focuses on a ChlE from Lactobacillus helveticus (Lh–ChlE), which has a flat temperature dependence. First, it was determined that conformational changes during Lh–ChlE turnover are not rate-limiting and that the overall rate depends on the chemical step at all temperatures. Next, Lh–ChlE’s temperature dependence was investigated using a conformational equilibrium model that assumes the existence of a temperature-dependent equilibrium between an active and an inactive conformation and an activation heat capacity …

Understanding The Role Of Toxs As A Bile Sensing Component Of The Toxrs Virulence Regulatory System In Vibrio Spp., Minje Kim

Dartmouth College Ph.D Dissertations

Pathogenic Vibrio bacteria, such as V. cholerae and V. parahaemolyticus, colonize in the human small intestine to cause severe gastrointestinal disease. During the infection, these bacteria encounter bile salts, antimicrobial cholesterol metabolites secreted into the intestine. Pathogenic Vibrio species have evolved to utilize bile salts as signals to regulate virulence. The signaling depends in part on ToxRS, a conserved co-component transmembrane transcription regulator. ToxRS consists of the transcription factor ToxR and its membrane-tethered binding partner ToxS. ToxS is required for ToxR stability and full transcriptional activity. Although bile salts are known to influence ToxRS-dependent virulence gene expression, the molecular …

In Vitro And In Silico Analysis Of The Antibacterial Activity Of Bioactive Compounds Extracted From Pineapple Peel, Wafa Mohammad Sadik, Iman Tajer Abdullah, Lana Abed Alnajar

Makara Journal of Science

Antibiotic resistance is a critical global challenge that requires the discovery of alternative therapeutic agents. Plants -derived compounds, such as those found in Ananas comosus (pineapple)peel, offer promising antibacterial potential. This study aimed to evaluate the antibacterial activity of pineapple peel extract using both in vitro and in silico approaches. Ethanolic extracts of pineapple peel were fractionated using silica gel chromatography, and the resulting fractions were analyzed by GC-MS. Antibacterial activity was tested against Gram-positive and Gram-negative pathogens using the agar well diffusion method, and the inhibition zones were recorded. Molecular docking was performed to assess the interaction of identified …

Oral Streptococcus And Vitamin B12 Deficiency In E-Cigarette Users: A Microbial–Nutrient–Neurotransmitter Axis Linking To Mood Disturbances, Maryam Sabah Naser, Ali Jabbar Abd Al-Hussain Alkawaz, Ali Abbas Hashim Almusawi, Ali Jalil Obaid, Hasanain Ayed Mohammed Al-Khafaji, Reihaneh Sabbaghzadeh

Karbala International Journal of Modern Science

Background: With the rising popularity of e-cigarettes, questions have emerged regarding their broader influence on oral ecology, nutrient absorption, and psychological health. Disruptions in the oral microbiome may alter vitamin B12 dynamics. This, in turn, may indirectly influence serotonin biosynthesis and mood regulation.

Methods: An observational cross-sectional study involved 150 young adults segregated into groups of 50 each as vapers, smokers, or non-users. Streptococcus sanguinis and vitamin B12 metabolism-related variable statuses methylmalonic acid and holotranscobalamin were quantified in samples, along with inflammatory markers interleukin-6, kynurenine/tryptophan ratio, and serotonin. Statistical techniques, including ANOVA and the Kruskal-Walli’s test, correlation, and serial mediation …

Transcription Factor Binding And Discovery Of Novel Gene In The Opportunistic Human Pathogen, Pseudomonas Aeruginosa, Alaina Westee

Symposium of Student Scholars

Pseudomonas aeruginosa (PA) is a gram-negative, ubiquitously-found bacterium that primarily causes nosocomial, or hospital-borne, infections within immunocompromised patients. Therefore, it has been deemed a critical priority pathogen by the World Health Organization (WHO) and the Center for Disease Control (CDC), generating a need for research on its fundamental biology. The Van Dyke laboratory focuses on proteins called transcription factors, which promote or repress gene expression to regulate an organism’s functioning. We are specifically studying the cadmium-responsive transcription factor, CadR, due to the importance of metals in virulence and the lack of information on PA’s response to metal fluctuations. We intend …

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 …

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 …

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 …

Reducing Food Scarcity: The Benefits Of Urban Farming, S.A. Claudell, Emilio Mejia

Journal of Nonprofit Innovation

Urban farming can enhance the lives of communities and help reduce food scarcity. This paper presents a conceptual prototype of an efficient urban farming community that can be scaled for a single apartment building or an entire community across all global geoeconomics regions, including densely populated cities and rural, developing towns and communities. When deployed in coordination with smart crop choices, local farm support, and efficient transportation then the result isn’t just sustainability, but also increasing fresh produce accessibility, optimizing nutritional value, eliminating the use of ‘forever chemicals’, reducing transportation costs, and fostering global environmental benefits.

Imagine Doris, who is …

Mutational Analysis Of The Nitrogenase Carbon Monoxide Protective Protein Cown Reveals That A Conserved C‑Terminal Glutamic Acid Residue Is Necessary For Its Activity, Dustin L. Willard, Joshuah J. Arellano, Mitch Underdahl, Terrence M. Lee, Avinash S. Ramaswamy, Gabriella Fumes, Agatha Kliman, Emily Y. Wong, Cedric P. Owens

Biology, Chemistry, and Environmental Sciences Faculty Articles and Research

Nitrogenase is the only enzyme that catalyzes the reduction of nitrogen gas into ammonia. Nitrogenase is tightly inhibited by the environmental gas carbon monoxide (CO). Many nitrogen fixing bacteria protect nitrogenase from CO inhibition using the protective protein CowN. This work demonstrates that a conserved glutamic acid residue near the C-terminus of Gluconacetobacter diazotrophicus CowN is necessary for its function. Mutation of the glutamic acid residue abolishes both CowN’s protection against CO inhibition and the ability of CowN to bind to nitrogenase. In contrast, a conserved C-terminal cysteine residue is not important for CO protection by CowN. Overall, this work …

Spatial Structure Formation By The Post-Transcriptional Gene Regulator Rsme In Pseudomonas Fluorescens Pf0-1, Anton Evans

Electronic Theses and Dissertations

Microorganisms are often found in microbial communities we call biofilms. Organisms living in these crowded environments have significant evolutionary pressure to retain access to the resources necessary to sustain life. My research uses the bacterium Pseudomonas fluorescens Pf0-1 to study how organisms evolve strategies to solve this crowding problem as aging colonies repeatedly generate mutant patches. These mutants expand the reach of the colony resulting in decreased local density as they push themselves up to the resource rich surface. These spatial structures result from social interactions between the mutant and the parental cells mediated through extracellular secretions, resulting in the …

Sympatric Soil Microbe Interactions Between Streptomyces And Fusarium Isolates, Lehren A. Olk-Szost

All NMU Master's Theses

Interkingdom interactions between soil bacteria and fungi may play a critical role in occurrence of disease suppressive soils, yet our understanding of these interactions remains limited. Streptomyces are well-known producers of antimicrobial compounds important to medicine and agriculture. Production of these secondary metabolites is often mediated by quorum sensing. Most Streptomyces research occurs in single species experiments, yet new metabolites have been discovered in interspecies co-culture experiments. Interspecies, intergenic, and interkingdom co-culture research will likely reveal many valuable compounds, and strengthen our understanding of complex ecological interactions in soil microbiomes. Interactions between sympatric Streptomyces and Fusarium isolates from disease suppressive …

A Critical Assessment Of The Role Of Clpxp-Mediated Proteolysis In The Development And Differentiation Of Chlamydia Trachomatis, Nicholas A. Wood

Theses & Dissertations

Chlamydia trachomatis, an obligate intracellular human pathogen, is the etiological agent of the most commonly reported bacterial sexually transmitted infection and the leading cause of preventable infectious blindness worldwide. In adapting to an intracellular niche, Chlamydia has evolved to eliminate superfluous genes from its chromosome. Despite its highly reduced genome, Chlamydia undergoes a complex developmental cycle in which the bacteria differentiate between two functionally and morphologically distinct forms: the infectious, non-replicative elementary body (EB) and the non-infectious, replicative reticulate body (RB). An EB initiates infection by binding to and inducing uptake into a host cell. Within the cell, the EB …

Treponema Denticola Synthesizes C-Di-Amp And Encodes The Cdaa-Type Diadenylate Cyclase Cdaa, Claire R. O'Brien

Theses and Dissertations

Periodontitis is a form of oral disease characterized by dysbiosis of the oral microbiome, leading to inflammation, bone resorption, and in severe cases, entire tooth loss, affecting 42% of adults in the US. One of the bacteria most associated with periodontal disease progression is Treponema denticola (Td), an oral spirochete which inhabits the mouth in small quantities during health but which can dominate the biofilms that form during periodontal disease. The ability of Td to survive in a disease environment and contribute to the progression of disease requires the use of robust signaling networks. Analysis of Td cultures …

Functional Residues Of Cjpata, Robert Lamont

Theses and Dissertations (Comprehensive)

Antibiotic resistance in pathogenic bacteria continues to challenge clinicians and threaten the lives of infected individuals. For this reason, new classes of antibiotics or new targets for antibiotic therapy are needed to circumvent this global health crisis. In Gram-negative bacteria, the enzymes peptidoglycan O-acetyltransferase A and B (PatA and PatB), are responsible for adding acetyl groups to the C-6 hydroxyl group of N-acetyl muramic acid (MurNAc) in peptidoglycan (PG). These acetyl groups are responsible for inhibiting the activity of lysozyme from host organisms that hydrolyze the β1-4 glycosidic linkage between MurNAc and N-acetylglucosamine (GlcNAc). The acetyl groups …

Potential Use Of Proteolytic Bacteria Paenibacillus Dendritiformis (Bt7) Isolated From Batu Tannery Effluents For The Detergent Industry, Chandran Masi, Degafneh Tadesse, Abate Ayele

Karbala International Journal of Modern Science

This research was aimed at identifying a bacterium that can produce alkaline proteases. As a result, bacteria that produce proteases were isolated from Batu tannery effluents, tested for protease synthesis on skim milk agar plates, and validated with a protease assay. Microscopic and molecular phylogenetic analyses identified Paenibacillus dendritiformis (BT7) as the bacterial isolate with the highest alkaline protease production. The isolate's maximum enzyme production was obtained by 2% inoculum size, 40°C temperature, 9.0 pH, and a 48-hour incubation time with production media components such as glucose, casein, MgCl2, and 2% NaCl. The maximal enzyme activity was 270 U/mL under …

Using Dietary Additives To Improve Palatability Of Diets Containing Single‐Cell Protein From Methanotrophic Bacteria In Yellowtail Kingfish (Seriola Lalandi) Diets, Luke Pilmer, Lindsey Woolley, Alan J. Lymbery, Michael Salini, Gavin Partridge

Fisheries Research Articles

Single-cell protein (SCP) derived from methanotrophic bacteria has significant potential as a fishmeal alternative in aquafeeds. However, SCP has known palatability issues, to overcome these issues tuna hydrolysate and garlic powder were tested as palatability enhancers against basal diets without these additives. This study tested the inclusion of SCP at four dietary levels of 0%, 10%, 20% and 30%, representing 0%, 25%, 50% and 75% fishmeal replacement in juvenile yellowtail kingfish (Seriola lalandi) (YTK) diets. YTK were fed these diets in triplicate over 35 days. Compared with the control diet, fish fed the SCP10% diet ate less feed, …

Studying The Lysine Acetylation Of Aconitase Isozymes In E. Coli, Sara Ottinger

Chemistry & Biochemistry Undergraduate Honors Theses

The contents of this thesis have been modified from the publication “Araujo J, Ottinger S, Venkat S, Gan Q and Fan C (2022) Studying Acetylation of Aconitase Isozymes by Genetic Code Expansion. Front. Chem. 10:862483”. Though studies have found multiple lysine sites in which acetylation takes place in Escherichia Coli aconitase, acetylation’s effects on the enzyme’s activity have yet to be studied. Aconitase is the dehydratase-hydratase found in the citric acid and glyoxylate cycles responsible for the reversible isomerization of citrate to isocitrate via cis-aconitate intermediate. There are two isoforms of aconitase in E. coli: AcnA and AcnB. In …

Annual Faculty Research Symposium 2022, Oakwood University

Proceedings

No abstract provided.

Characterization Of A Medium-Dependent Streptomyces Developmental Mutant, Dylan Gray, Jennifer A. Bennett

Undergraduate Distinction Papers

Streptomyces coelicolor is a soil-dwelling, Gram-positive Actinobacteria. Streptomyces species produce thousands of secondary metabolites which include many antibiotics used in medicine today. In Streptomyces development, as colonies grow, secondary metabolites are produced, and ultimately mature spores are dispersed. The production of each of these secondary metabolites in wild-type Streptomyces is determined by a distinct biosynthetic pathway. In order to identify new genes for antibiotic production and other aspects of development, an engineered Tn5-derived transposon was used to mutagenize wild-type cells in vivo and produce single, stable insertions.

Colonies that were visually distinct from the wild type were selected for further …

Escherichia Coli Alanyl-Trna Synthetase Maintains Proofreading Activity And Translational Accuracy Under Oxidative Stress, Arundhati Kavoor, Paul Kelly, Michael Ibba

Biology, Chemistry, and Environmental Sciences Faculty Articles and Research

Aminoacyl-tRNA synthetases (aaRSs) are enzymes that synthesize aminoacyl-tRNAs to facilitate translation of the genetic code. Quality control by aaRS proofreading and other mechanisms maintains translational accuracy, which promotes cellular viability. Systematic disruption of proofreading, as recently demonstrated for alanyl-tRNA synthetase (AlaRS), leads to dysregulation of the proteome and reduced viability. Recent studies showed that environmental challenges such as exposure to reactive oxygen species can also alter aaRS synthetic and proofreading functions, prompting us to investigate if oxidation might positively or negatively affect AlaRS activity. We found that while oxidation leads to modification of several residues in Escherichia coli AlaRS, unlike …

Characterizing The Amino Acid Activation Center Of The Naturally Editing-Deficient Aminoacyl-Trna Synthetase Phers In Mycoplasma Mobile, Nien-Ching Han, Arundhati Kavoor, Michael Ibba

Biology, Chemistry, and Environmental Sciences Faculty Articles and Research

To ensure correct amino acids are incorporated during protein synthesis, aminoacyl-tRNA synthetases (aaRSs) employ proofreading mechanisms collectively referred to as editing. Although editing is important for viability, editing-deficient aaRSs have been identified in host-dependent organisms. In Mycoplasma mobile, editing-deficient PheRS and LeuRS have been identified. We characterized the amino acid activation site of MmPheRS and identified a previously unknown hyperaccurate mutation, L287F. Additionally, we report that m-Tyr, an oxidation byproduct of Phe which is toxic to editing-deficient cells, is poorly discriminated by MmPheRS activation and is not subjected to editing. Furthermore, expressing MmPheRS and the hyperaccurate variants renders …

Biodegradation Of Rubber Particles In Soil: Using Acclimated Bacteria Isolated From Kansas Soil To Degrade Cryogrinds In Slurry, Shane Graham

Williams Honors College, Honors Research Projects

This study investigated the viability of bioremediating rubber cryogrind using enriched indigenous bacteria. To begin the experiment, soils from three highway roadside locations in Kansas, KS 96 and West, KS 400 and 143^rd, and 199^th, were collected and transported to the lab to be studied. An initial soil characterization was run on the soil samples using distilled (DI) water mixture and 0.01 M CaCl₂ to assess conductivity. The soils were tested to gather a baseline of the relationship between pH and conductivity and the impact of its distance from the roadside. Bacteria were isolated from …

Antibiotic Permeation In Gram-Negative Bacteria And Contribution Of Inflammasome Activation And Pyroptosis In Pathogenesis Of Salmonella Systemic Infection, Ankit Pandeya

Theses and Dissertations--Chemistry

Antibiotic resistance is one of the major global issues in the field of public health and medicine. Good antibiotic candidates need to be selectively toxic, inhibit cellular target, and effectively penetrate and accumulate in bacterial cells. The last factor is a formidable barrier in the development of antimicrobials effective in Gram-negative bacteria, due to the presence of two layers of cell envelope. The first half of my thesis focuses on understanding the permeation of small molecules through this formidable cell envelope, distribution inside the cell of Gram-negative bacteria, and design of novel methods to make small molecules effectively cross the …

Enzymatic Degradation Of Microcystin-Lr By Microcystinase (Mlra), Faisal Alqhtani

Graduate Theses and Dissertations

Microcystin-LR (MC-LR) is affecting the water supply worldwide. Hence, a way to eliminate this toxin is an essential target. In this study, successful cloning of the mlrA gene and producing MlrA enzyme that can degrade the cyclic MC-LR to linearized MC-LR was done. MlrA protein was expressed in Escherichia coli BL-21 (E. coli). Also, enhancing the MlrA yield by adding nickel to LB media was a success in producing more MlrA enzyme from the same volume. Even though the enzyme showed no activity after adding Ni, the enzyme was expressed at a higher yield. Furthermore, it was to investigate adding …

A Conserved Structural Role For The Walker-A Lysine In P-Loop Containing Kinases, Fatlum Hajredini, Ranajeet Ghose

Publications and Research

Bacterial tyrosine kinases (BY-kinases) and shikimate kinases (SKs) comprise two structurally divergent P-loop containing enzyme families that share similar catalytic site geometries, most notably with respect to their Walker-A, Walker-B, and DxD motifs. We had previously demonstrated that in BY-kinases, a specific interaction between the Walker-A and Walker-B motifs, driven by the conserved “catalytic” lysine housed on the former, leads to a conformation that is unable to efficiently coordinate Mg²⁺•ATP and is therefore incapable of chemistry. Here, using enhanced sampling molecular dynamics simulations, we demonstrate that structurally similar interactions between the Walker-A and Walker-B motifs, also mediated by …

Oxidation Alters The Architecture Of The Phenylalanyl-Trna Synthetase Editing Domain To Confer Hyperaccuracy, Pooja Srinivas, Rebecca E. Steiner, Ian J. Pavelich, Ricardo Guerrera-Ferreira, Puneet Juneja, Michael Ibba, Christine M. Dunham

Biology, Chemistry, and Environmental Sciences Faculty Articles and Research

High fidelity during protein synthesis is accomplished by aminoacyl-tRNA synthetases (aaRSs). These enzymes ligate an amino acid to a cognate tRNA and have proofreading and editing capabilities that ensure high fidelity. Phenylalanyl-tRNA synthetase (PheRS) preferentially ligates a phenylalanine to a tRNA^Phe over the chemically similar tyrosine, which differs from phenylalanine by a single hydroxyl group. In bacteria that undergo exposure to oxidative stress such as Salmonella enterica serovar Typhimurium, tyrosine isomer levels increase due to phenylalanine oxidation. Several residues are oxidized in PheRS and contribute to hyperactive editing, including against mischarged Tyr-tRNA^Phe, despite these oxidized residues not …

Insights Into Halophilic Microbial Adaptation: Analysis Of Integrons And Associated Genomic Structures And Characterization Of A Nitrilase In Hypersaline Environments, Sarah Sonbol

Theses and Dissertations

Hypersaline environments are extreme habitats that can be exploited as biotechnological resources. Here, we characterized a nitrilase (NitraS-ATII) isolated from Atlantis II Deep brine pool. It showed higher thermal stability and heavy metal tolerance compared to a closely related nitrilase.

We also studied integrons in halophiles and hypersaline environments. Integrons are genetic platforms in which an integron integrase (IntI) mediates the excision and integration of gene cassettes at specific recombination sites. In order to search for integrons in halophiles and hypersaline metagenomes, we used a PCR-based approach, in addition to different bioinformatics tools, mainly IntegronFinder.

We found that integrons and …

Design, Synthesis, And Evaluation Of Carbapenem And Cephalosporin Antibiotics To Counter Resistant 21st Century Pathogens, Maha Alqurafi

Chemistry Theses and Dissertations

Antibiotics represent one of mankind’s most important discoveries, enabling longer, more productive lives. Carbapenem antibiotics are one of the most potent classes of β-lactams and often represent the last resort used to treat patients who are seriously stricken by bacterial infections. Carbapenems possess a broad spectrum of antibacterial activity including efficacy against the majority of Gram-positive and Gram–negative bacteria. Unfortunately, the emergence of antibiotic resistant strains is posing a serious threat to existing antibiotics. New discoveries in the antibiotic field are desperately needed to counter the threat of rapidly evolving bacterial resistance. Despite the investment of billions of dollars, and …

Project Alien, Rebecca Mccallin, Madelyn Hoying, Alex Evans, Matthew Nestler, Karli Rae Sutton, Garett Craig, Lucia Secaia Del Cid, Alexander Guy, Rachel Fernandez, Amanda Trusiak, Paige Aley, Ingabire Gakwerere, Nina Dorfner, Maria Mosbacher, Mary Flavin, Selvin Hernandez, Audrey Steen, Benjamin Kazimer

Undergraduate Research and Scholarship Symposium

Project ALIEN is a comprehensive plan to send humans to Mars to look for life on the Martian surface while exploring the viability and adaptability of terrestrial microbes in Martian atmospheric conditions. ALIEN will use a ballistic capture trajectory to get to Mars and stay in aerostationary orbit for a 30-day surface mission, during which two surface crewmembers will perform a variety of experiments to achieve the mission’s goals of Martian microbial discovery within brines of the Gale Crater and terrestrial microbe adaptability and viability to Martian conditions. Experimentation is based on the presumption that Martian microbes are metabolically similar …