Biochemistry, Biophysics, and Structural Biology Commons^™

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

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

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 …

Isolation And Characterization Of A Novel Thermo-Solvent-Stable Lipase From Pseudomonas Brenneri And Its Application In Biodiesel Synthesis, Priyanka Priyanka, Gemma K. Kinsella, Gary T. Henehan, Barry J. Ryan

Articles

Pseudomonads are one of the most studied species of bacteria as they display remarkable metabolic and physiological versatility. This enables them to colonize a wide variety of terrestrial and aquatic habitats, generating biotechnologically interesting enzymes. Here, the partial purification and characterization of a novel, extracellularly-produced, lipase from Pseudomonas brenneri is described. The partially purified lipase was active over a broad pH range (5.0–9.0) and was stable at 70 °C for 45 min. The lipase displayed significant stability, and in some cases activation, in the presence of organic solvents with log P≥2.0. Such stability characteristics indicated that this lipase could potentially …

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

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 …

Characterization Of Wssf; A Putative Acetyltransferase From Achromobacter Insuavis And Pseudomonas Fluorescens, Cody Reese

Theses and Dissertations (Comprehensive)

Biofilms are a survival mechanism commonly employed by communities of bacteria for adherence and protection. Bacteria produce a matrix of polymers (e.g. exopolysaccharides, such as cellulose) that allow them to exert control on their local environment. In the case of cellulose biofilms, acetylation (addition of acetate on carbohydrates) is paramount for polymer integrity and in some cases virulence. For this research, the wrinkly spreader (WS) genotype of the emergent human pathogen Achromobacter insuavis facilitates infections of the eyes of contact lens wearers and the lungs of Cystic Fibrosis patients (CF). Chronic infections have created a growing concern for the protective …

Isolation, Purification And Characterization Of A Novel Solvent Stable Lipase From Pseudomonas Reinekei, Barry Ryan, Priyanka Priyanka, Gemma K. Kinsella, Gary T. Henehan

Articles

The Pseudomonas sp. have been long recognized for their exogenous lipolytic activities yet the genus still contains a lot of unexplored strains. Due to the versatile metabolic machinery and their potential for adaptation to fluctuating environmental conditions Pseudomonas sp. are of great interest for biotechnological applications. In this study, a new extracellularly produced lipolytic enzyme from Pseudomonas sp. (P. reinekei) was purified and characterized. The production of lipase from P. reinekei (H1) was enhanced 10-fold by optimizing the nitrogen source. The 50 kDa H1 lipase was purified using negative and positive mode anion exchange chromatography. The purified lipase was active …

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

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 …

Examination Of Pseudomonas Fluorescence As A Recombinant Expression Host: Cloning, Expression, And Chromatography, Ahmed K.Ali Elmasheiti

Graduate Theses and Dissertations

In an effort to expand the pool of bacterium useful for biotechnology applications, Pseudomonas fluorescens, a common gram negative microbe, was examined for its ability to function in a recombinant setting. P. fluorescens is ubiquitous in nature and was initially identified as a soil bacterium found in dirt and is typically associated with plant material. Past literature indicates that it shared characteristics common to Escherichia coli and Bacillus subtilis, including simple growth conditions and potential cloning vectors, providing motivation to look into both the upstream and downstream characteristics of this bacterium. First, it was demonstrated that P. fluorescens could be …

Analysis Of Histone Deacetylase Involvement In Pseudomonas Syringae-Triggered Chromatin Changes, Jennifer Wies, Victoria Shum, Karin V. Van Dijk

UCARE Research Products

I had the great privilege of working with Dr. Karin van Dijk, through UCARE, researching the specific pathways through which histone deacetylation occurs in plants during the 2015-2016 academic year. My first year conducting research helped me develop my technical skills and learn about experimental protocols and how to conduct them. I would like to continue my research during the 2016-2017 academic year and now that I have a year of research experience, be able to further develop my skills and learn more about my research project.

Background

Pseudomonas syringae is a bacterial pathogen that is well known for causing …

Investigations Into The Molecular Mechanisms Of Bacterial Pathogen-Host Interactions: Construction Of A Dual Plasmid System For Incorporation Of Unnatural Amino Acids Into Pseudomonas Syringae Pv. Tomato Dc3000, Scotty D. Raber

Department of Chemistry: Dissertations, Theses, and Student Research

A dual plasmid system for the incorporation of unnatural amino acids into plant pathogen, Pseudomonas syringae pv. tomato DC3000, has been designed. This invention is expected to allow (a) mutations of proteins synthesized by the bacterium, P. syringae pv. tomato DC3000, that can capture molecular targets, especially for such modified proteins secreted by the phytopathogen into the host plant cells of A. thaliana and S. lycopersicum, (b) expression of biological probes in the bacterial species to monitor changes in redox, nutritional, and other small molecule states over pre-, post- and in situ disease stages, and (c) secretion of such …

Diatom Assemblages Promote Ice Formation In Large Lakes, N. A. D'Souza, Y. Kawarasaki, J. D. Gantz, R. E. Lee, B. F.N. Beall, Y. M. Shtarkman, Z. A. Koçer, S. O. Rogers, H. Wildschutte, G. S. Bullerjahn, R. M.L. Mckay

Great Lakes Institute for Environmental Research Publications

We present evidence for the directed formation of ice by planktonic communities dominated by filamentous diatoms sampled from the ice-covered Laurentian Great Lakes. We hypothesize that ice formation promotes attachment of these non-motile phytoplankton to overlying ice, thereby maintaining a favorable position for the diatoms in the photic zone. However, it is unclear whether the diatoms themselves are responsible for ice nucleation. Scanning electron microscopy revealed associations of bacterial epiphytes with the dominant diatoms of the phytoplankton assemblage, and bacteria isolated from the phytoplankton showed elevated temperatures of crystallization (T c) as high as -3 °C. Ice nucleation-active bacteria were …

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, …

Characterizing The Role Of The Bacterial Metallothionein, Smta, In Mammalian Infection, Stephanie R. Davis

Honors Scholar Theses

Mammalian metallothioneins (MT) are induced by various immunomodulatory molecules and are involved in a spectrum of immune processes such as essential metal homeostasis, detoxification of certain heavy metals, inflammation, and immune cell trafficking [1-3]. A bacterial metallothionein, SmtA, shares some sequence homology with mammalian MT as well as its metal-binding capabilities [4]. In addition to its ability to sequester heavy metals, eukaryotic MT has also been shown to scavenge free radicals such as reactive oxygen and nitrogen species (ROS, RNS), interfering with their toxic effects on cells and potentially influencing their regulatory roles in cell proliferation and differentiation [5, 6]. …

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 …