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Full-Text Articles in Biochemistry, Biophysics, and Structural Biology

Identification And Characterization Of Genetic Elements That Regulate A C-Di-Gmp Mediated Multicellular Trait In Pseudomonas Fluorescens, Collin Kessler Aug 2022

Identification And Characterization Of Genetic Elements That Regulate A C-Di-Gmp Mediated Multicellular Trait In Pseudomonas Fluorescens, Collin Kessler

Electronic Theses and Dissertations

Microbial communities contain densely packed cells where competition for space and resources are fierce. These communities are generally referred to as biofilms and provide advantages to individual cells against immunological and antimicrobial intervention, dehydration, and predation. High intracellular pools of cyclic diguanylate monophosphate (c-di-GMP) cause cells to aggregate during biofilm formation through the production of diverse extracellular polymers. Genes that encode c-di-GMP catalytic enzymes are commonly mutated during chronic infections where opportunists display enhanced resistance to phagocytosis and antibiotics. Our lab uses an emergent multicellular trait in the model organism Pseudomonas fluorescens Pf0-1 to study the emergence of c-di-GMP mutations …


Growth Outcomes Of Pseudomonas Aeruginosa Inhibitor Of Vertebrate Lysozyme Knockouts In Conditions Mimicking The Cystic Fibrosis Lung Environment, Amani Gaddy Jul 2022

Growth Outcomes Of Pseudomonas Aeruginosa Inhibitor Of Vertebrate Lysozyme Knockouts In Conditions Mimicking The Cystic Fibrosis Lung Environment, Amani Gaddy

Master of Science in Chemical Sciences Theses

Pseudomonas aeruginosa (PA) is a Gram-negative bacterium, often found in cystic fibrosis (CF) patients and can lead to the decline of lung functioning and premature death in 80% of infected patients when microcolonies form within the mucin of the lung. Due to its major capacity for antibiotic resistance, an alternative strategy towards defending against the bacterial invasion of PA is by the antibacterial activity of our own innate immune system with use of elements such as lysozyme. Pseudomonas aeruginosa inhibitor of vertebrate lysozyme class 1 (Ivyp1) is a periplasmic protein produced by gram-negative bacteria that inhibits the enzymatic activity of …


Eskape Pathogens: The Clinical Prevalence And Molecular Mechanisms Of Antibiotic Resistance, Anusha Attre May 2022

Eskape Pathogens: The Clinical Prevalence And Molecular Mechanisms Of Antibiotic Resistance, Anusha Attre

Honors Scholar Theses

The ESKAPE pathogens (Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa, and Enterobacter species) are the leading cause of all nosocomial, or healthcare-associated (HAI), infections (Navidinia, 2016). The purpose of this research study is to determine the burden of ESKAPE infections on healthcare and study the antibiotic resistance in these high-risk pathogens to provide direction for researchers to develop new antimicrobial innovations to reduce ESKAPE infectivity and improve patient outcomes. To study the burden of ESKAPE infections, this review analyzes the current statistics explaining the clinical prevalence of each pathogen in causing HAIs. Additionally, each pathogen is …


A Tale Of Two Adaptors: The Role Of Two Adaptor Proteins In Pseudomonas Aeruginosa Chp Chemosensory System Signal Transduction And Implications For Chemosensory Array Formation, Zachary Hying May 2020

A Tale Of Two Adaptors: The Role Of Two Adaptor Proteins In Pseudomonas Aeruginosa Chp Chemosensory System Signal Transduction And Implications For Chemosensory Array Formation, Zachary Hying

Theses and Dissertations

Bacteria use chemosensory systems to coordinate environmental signals to direct chemotaxis and make lifestyle decisions such as surface attachment and biofilm formation. Chemosensory systems form extended arrays with pseudo-hexagonal symmetry that are essential for efficient signal transduction. These arrays consist of three essential components: Methyl-Accepting Chemotaxis proteins (MCPs), which receive signals, a histidine kinase to coordinate cell responses through phosphorylation of response regulators, and an adaptor protein to transduce conformational change and facilitate array formation. Pseudomonas aeruginosa uses four chemosensory systems to control flagellar-based motility, type IV pili-mediated twitching motility and acute virulence, and biofilm formation. The Chp chemosensory system …


Pseudomonas And Bacillus Soil Isolates Produce Antibiotics, Chelsea Brandt, Dr. Lori Scott Jan 2020

Pseudomonas And Bacillus Soil Isolates Produce Antibiotics, Chelsea Brandt, Dr. Lori Scott

Identifying and Characterizing Novel Antibiotic Producing Microbes From the Soil

The recent emergence of antibiotic resistance bacterial strains presents a significant challenge and threat to human healthcare. While new methods of treatment such as bacteriophage therapy and combinations of existing antibiotics are being researched, the human population is in dire need of new antibiotics to replace those that are ineffective. This research addresses this need by identifying antibiotic producing bacteria in a soil sample from Davenport, IA. This project is a collaboration with the Tiny Earth Project Initiative (TEPI), which is a global network of educators and students focused on studentsourcing antibiotic discovery from soil. Microbiology lab techniques and 16S …


Microbiome Of Commercial Broilers Through Evisceration And Immersion Chilling, John A. Handley May 2018

Microbiome Of Commercial Broilers Through Evisceration And Immersion Chilling, John A. Handley

Graduate Theses and Dissertations

The United States poultry industry generated 38.6 billion pounds (17,500 metric ton) of meat in 2014 which averaged to 121 pounds (55 kg) per individual of the U.S that same year. Of that meat generated by the poultry industry, an estimated 1 million cases of Salmonellosis will occur. Out of the 1 million cases approximately 40, 000 to 50,000 will be confirmed cases by the CDC. Recently, the USDA has requested changes in the inspection process and are currently allowing processors more freedom to utilize innovation to drive the increase in safer and more desirable foods. The new standards set …


A Novel Link Between The Chemotaxis And Biofilm Dispersion Systems Of Pseudomonas Aeruginosa, Jesse Michael Reinhardt May 2017

A Novel Link Between The Chemotaxis And Biofilm Dispersion Systems Of Pseudomonas Aeruginosa, Jesse Michael Reinhardt

Theses and Dissertations

Bacterial chemotaxis is the movement of a cell towards an attractant or away from a repellent. This controlled movement is possible due to the chemotaxis system, which is typically made up of several proteins that collectively sense the stimuli and transduce the signal within the cell to mediate a motility response. The chemotaxis proteins of Pseudomonas aeruginosa are encoded in two clusters, which are located at different regions of the chromosome: che I and che V. These gene clusters are known to control chemotaxis via swimming, or flagellar-based, motility. When expressed, these chemotaxis proteins associate with each other to form …


Host Pathogen Interactions: Is Arabidopsis Thaliana Remembered By Its Nemesis Pseudomonas Syringae?, Daniel Z. Kreiser May 2012

Host Pathogen Interactions: Is Arabidopsis Thaliana Remembered By Its Nemesis Pseudomonas Syringae?, Daniel Z. Kreiser

Lawrence University Honors Projects

Plants contain innate immune systems that deter pathogen infection. Pattern recognition receptors bind microbe-associated molecular patterns (MAMPs), triggering immunity. MAMPs are proteins exclusive to pathogens that are typically indispensable for their survival. For this reason, MAMPs cannot be mutated or removed without causing pathogen death. However, this does not necessitate constitutive expression of MAMPs. In this study, the MAMP response of Arabidopsis thaliana was utilized to determine differential detection of MAMPs expressed by Pseudomonas syringe pv. tomato DC3000 when pretreated with A. thaliana. Results demonstrated that more MAMPs are detected when P. syringae had previously encountered A. thaliana, …


A Messenger Molecule Governs Interdependency In An Evolved Pseudomonas Aeruginosa Biofilm Community, Thomas Macelliott Johnson Jan 2011

A Messenger Molecule Governs Interdependency In An Evolved Pseudomonas Aeruginosa Biofilm Community, Thomas Macelliott Johnson

Honors Theses and Capstones

Biofilm populations are known to harbor great diversity, but the importance of this diversity is not fully understood. A likely contributor to this variation is the second messenger molecule cyclic-di-GMP: low levels associate with a planktonic lifestyle while high levels favor biofilm formation. In ongoing studies of an evolving biofilm population of Pseudomonas aeruginosa (PA), we observed extensive ecological diversification that may relate to this lifestyle switch. In PA, the gene bifA encodes a phosphodiesterase that is known to degrade cyclic-di-GMP and reduce biofilm. This gene was cloned onto a plasmid under control of an inducible promoter and the plasmid …