Microbiology Commons^™

Specialized Replication Operons Control Rhizobial Plasmid Copy Number In Developing Symbiotic Cells, Clarice Lorraine Perry

Theses and Dissertations

The rhizobium – legume symbiosis is a complex process that involves genetic cooperation from both bacteria and plants. Previously, our lab described naturally occurring accessory plasmids in rhizobia that inhibit this cooperation. A transposon mutagenesis was performed on the plasmids to detect the genetic factor that blocked nitrogen fixation. Several of the plasmids were found to possess a replication operon that when disrupted by transposon insertion, restored symbiotic function. This study describes an in-depth investigation into one of those plasmids, pHRC377, and into its replication operon. The operon, which we have called repA2C2, comes from the repABC family of …

Gene Networks Involved In Competitive Root Colonization And Nodulation In The Sinorhizobium Meliloti-Medicago Truncatula Symbiosis, Ryan D. Vanyperen

Theses and Dissertations

The rhizobia-legume symbiosis is the most agriculturally significant source of naturally fixed nitrogen, accounting for almost 25% of all biologically available nitrogen. Rhizobia-legume compatibility restrictions impose limits on symbiotic nitrogen fixation. In many cases, the molecular basis for symbiotic compatibility is not fully understood. The signals required for establishing a symbiotic partnership between nitrogen-fixing bacteria (e.g. Sinorhizobium meliloti) and leguminous plants (e.g. Medicago truncatula) have been partially characterized at the molecular level. The first stage of successful root colonization is competitive occupation of the rhizosphere (which is poorly understood). Here, the bacteria introduce themselves as potential symbiotic partners …

The Detection And Molecular Evolution Of Francisella Tularensis Subspecies, Mark K. Gunnell

Theses and Dissertations

Francisella tularensis is the etiological agent of tularemia, a zoonotic disease with worldwide prevalence. F. tularensis is a highly pathogenic organism and has been designated as a potential biothreat agent. Currently there are four recognized subspecies of F. tularensis: tularensis (type A), holarctica (type B), mediasiatica, and novicida. In addition, genomic studies have further subdivided type A tularensis into two subclassifications, type A.I and type A.II. These two subclassifications differ in geographic distribution with type A.I appearing mainly in the Eastern United States and type A.II appearing mainly in the Western United States. Because of differences of virulence among the …

Biofilm Binding Capabilities Of Yersinia Pseudotuberculosis Mutants, Bailey Benson, Dr. David Erickson

Journal of Undergraduate Research

Yersinia pestis — the causative agent of the deadly bubonic plague, which killed over one-third of Europe in the 14th century – spreads quickly from person to person due to its ability to create a biofilm, characterized by bacterial adhesion to themselves and surfaces. The bacteria infects fleas and forms a biofilm in their midgut, which causes the flea to both feed more often and cough up bacteria biofim into each new host. In this way, the formation of a strong biofilm is essential for the rapid spread of the bubonic plague. In my experiment, I analyzed which genes would …

Vibrio Cholera: Detection And Destruction, Amber Brown, Dr. Julianne Grose

Journal of Undergraduate Research

Cholera, the Disease: Cholera is a disease that affects three to five million people each year with approximately 100,000 deaths. Transmitted mainly by the drinking-­‐water supply, it causes an infection in the small intestine leading to severe diarrhea and vomiting. If left untreated, it can cause death within hours. The disease is caused by the bacterium Vibrio cholerae which was first isolated by Filippo Pacini in 1854. Vibrio cholerae is gram negative, comma shaped, and flagellated. It is easily treated with modern water purification techniques, and as such it is most prevalent in developing countries that lack this infrastructure. Countries …

Understanding The Role Of Estrogen In The Mucosal Immune Response, Youna Choi, Dr. Eric Wilson

Journal of Undergraduate Research

Most antigens (foreign substances) enter an organism via mucosal surfaces. Thus, understanding the mechanisms involved in immune protection at these surfaces is of paramount importance. Immune responses are highly dependent on homing mechanisms responsible for directing lymphocyte (white blood cell) migration and accumulation at target tissues. Estrogen control of lymphocyte homing within the uterus has recently been established (2).

Identifying And Characterizing Yeast Pas Kinase 1 Substrates Reveals Regulation Of Mitochondrial And Cell Growth Pathways, Desiree Demille

Theses and Dissertations

Glucose allocation is an important cellular process that is misregulated in the interrelated diseases obesity, diabetes and cancer. Cells have evolved critical mechanisms for regulating glucose allocation, one of which is sensory protein kinases. PAS kinase is a key sensory protein kinase that regulates glucose allocation in yeast, mice and man; and is a novel therapeutic target for the treatment of metabolic diseases such as obesity, diabetes and cancer. Despite its importance, the molecular mechanisms of PAS kinase function are largely unknown. Through large-scale protein-interaction studies, we have identified 93 novel binding partners for PAS kinase which help to expand …

The Antioxidant And Dna Repair Capacities Of Resveratrol, Piceatannol, And Pterostilbene, Justin Ryan Livingston

Theses and Dissertations

Lifestyle diseases represent a large burden on developed societies and account for much morbidity worldwide. Research has shown that eating a diet rich in fruit and vegetables helps to ameliorate and prevent some of these diseases. Antioxidants found in fruits and vegetables may provide a substantial benefit in reducing disease incidence. This thesis examines the antioxidant properties of resveratrol, piceatannol, and pterostilbene, and the ability of Burkitt's Lymphoma (Raji) cells to uptake these three antioxidants. It also studies the effect of the antioxidants in protecting against DNA damage and their role in DNA repair following oxygen radical exposure in Raji …

Advancing Phage Genomics And Honeybee Health Through Discovery And Characterization Of Paenibacillaceae Bacteriophages, Bryan Douglas Merrill

Theses and Dissertations

The Paenibacillaceae family of bacteria includes two species known to infect the hives of honeybees, Paenibacillus larvae and Brevibacillus laterosporus. P. larvae, the causative agent of American Foulbrood (AFB) causes a lethal infection of honeybee larvae, while B. laterosporus is a secondary invader following European Foulbrood (EFB) infection. Increasing antibiotic resistance of P. larvae bacteria has prompted a search for alternative treatment methods for this disease. Bacteriophages are the most diverse life forms on earth and can provide important insights about the bacterial hosts they infect. However, few Paenibacillaceae phages have been isolated or characterized. In this study, the first …

Isolation And Host Range Of Staphylococcus Aureus Bacteriophages And Use For Decontamination Of Fomites, Kyle C. Jensen

Theses and Dissertations

Staphylococcus aureus is a common bacterium found on the skin and mucosal membranes of about 20% of the population. S. aureus growth on the skin is harmless, but if it bypasses the skin it can causes life-threatening diseases such as pneumonia, meningitis, bacteremia, and sepsis. Antibiotic-resistant strains of S. aureus, called Methicillin Resistant S. aureus (MRSA), are resistant to most antibiotics except vancomycin. However, vancomycin resistant strains of MRSA are becoming more common. In this study, 12 phages were isolated capable of infecting human S. aureus and/or MRSA strains. Five phages were discovered through mitomycin C induction of prophages and …

High Salinity Stabilizes Bacterial Community Composition And Activity Through Time, Tylan Wayne Magnusson

Theses and Dissertations

Dormancy is a plausible strategy for bacteria to overcome the effects of temporal fluctuations in resources or stresses and await more “optimal” conditions to resume metabolic activity and growth. Seasonal changes in environmental conditions force microbes to adjust their metabolic activity accordingly, and community composition drastically shifts. In extreme environments, however, the overriding effects of a constant stress may constrain the need or benefit of bacteria entering dormancy. In hypersaline lakes, high metabolic activity is required to maintain adaptations that permit survival. Sampling from six lakes on a salinity gradient (0.05% – 30.3%), we measured seasonal fluctuations in bacterial dormancy …

Engineering A Pathogen Specific High Affinity T-Cell Receptor Called Llo56, John Hancock, Dr. Scott Weber

Journal of Undergraduate Research

CD4+ helper T-cells play a vital role in the body’s immune response. When infectious agents attack the body, phagocytes engulf these invaders and present a peptide segment of the pathogen on a receptor (called MHCII). These receptors are located on the surface of the cell and the displayed peptide is termed an epitope. CD4+ T-cells with T-cell receptors (TCRs) specific for the displayed peptide bind to the MHCII complex. It is this binding that releases chemical signals to initiate an immune response. A disadvantage of TCRs is that their wild-type affinity for MHC is low and that they are membrane …

Mapping Interaction Through Compensatory Phou Mutants In Escherichia Coli, Tanner Dean, William Mccleary

Journal of Undergraduate Research

The purpose of this experiment was to identify the physical interaction site between two proteins in Escherichia Coli. These two proteins, PhoU and PhoR, are two proteins involved in Phosphate signal transduction. When these two proteins are mutated, so they no longer interact, the pathway is broken and signaling is inhibited. To break this pathway, we mutated one protein (PhoR) until we developed several mutations that no longer interact with PhoU. This loss of interaction is caused by a physical change to the site of interaction between the two proteins. We hypothesized that we could find a naturally occurring PhoU …

Analysis Of Anti-Dengue Antibodies, Lauren Syndergaard, Brian Poole

Journal of Undergraduate Research

Dengue virus is a mosquitoes-borne virus that causes dengue fever. It is found primarily in tropical areas with over a third of the world’s population living in at-risk areas (WHO). The number of infections has grown rapidly in recent years with as many as 50 to 100 million infections occur each year (WHO). Though not widely present in the United States (small outbreaks occur with some regularity in Texas from the Mexican border; Hawaii and Florida relatively recently had cases), many travelers endemic areas contract the virus. Though several are being studied, as yet, there are no vaccines available for …

Discovery And Characterization Of Bacteriophage To Control Mrsa, Jacob B. Hatch, Bradford Berges

Journal of Undergraduate Research

About 20% of humans are carriers of Staphylococcus aureus (SA). There were an estimated 11,000 deaths in the United States in 2005 attributed to SA, with the majority caused by MRSA (Methicillin Resistant Staphylococcus Aureus) isolates [1]. Many MRSA isolates have developed resistance to all but one antibiotic drug: vancomycin. However, other bacteria have developed resistance to vancomycin, suggesting that in time MRSA will likewise become non-responsive to this last available drug and MRSA infections will be untreatable. This project looks to find an alternate method of MRSA treatment. Bacteriophage (phage) are viruses that infect bacterial cells in order …

Use Of Humanized Mice To Study The Production Of Human Antibodies, Steven Hallam, Dr. Bradford Berges

Journal of Undergraduate Research

The human immune system is composed of two main subsets: innate and adaptive immunities. Among the adaptive immune cells, B cells play a vital role in stopping infectious agents through the production of antigen specific antibodies. Human B cells are important targets of infection for many human-specific viruses that are poorly understood. Since the infection and study of human subjects is not possible, animal models have been developed to mimic the human immune environment. Rag2-/-γc-/- mice engrafted with human hematopoietic stem cells produce human B lymphocytes and these cells are capable of mounting antigen-specific human antibody responses. However, there is …

Fire Blight Treatment With Lytic Bacteriophage, Todd Jarvis, Julianne Grose

Journal of Undergraduate Research

Fire Blight, caused by the bacteria Erwinia amylovora, is a highly contagious fruit tree disease that is difficult to treat. This disease causes a tree to whither away, as if it had been burned. It is estimated that Fire Blight causes more than a 100 million dollar loss in agricultural goods each year¹. In an attempt to treat fire blight and prevent it from spreading, large doses of antibiotics are sprayed on infected trees. These antibiotics do little in the way of helping to treat the trees. In addition, the antibiotic run off from the treatment finds …

Lymphoblastoid Cell Line Generation From Sle Patient Lymphocytes, Vera Mayhew, Brian Poole

Journal of Undergraduate Research

Epstein-Barr Virus (EBV) is one of the viruses found most frequently in the human population. Approximately 95% of the population is infected in the United Sates by the age of 40. When primary infection occurs is young adulthood approximately 50% of cases result in infectious mononucleosis. Whether EBV infection results in mononucleosis manifestations or not, the virus stays latent in the infected individual’s B cells for the rest of their life.

Effect Of Ebi2 On B Cell Migration, Jeffrey Mella, Brian Poole

Journal of Undergraduate Research

My mentored research project was a terrific experience. I have been mentored with Dr. Brian Poole for the last three years. As a result of the project that was made possible by the ORCA grant, I was the first author on an abstract submitted and accepted by the International Immunology Summit. This last October I attended the International Immunology Summit in Las Vegas, Nevada. Dr. Poole and I presented our research and I responded to questions from the audience. I am currently an author on a manuscript that in progress that has been submitted for review. I have enjoyed my …

P. Larvae Bacteriophages As A Treatment For American Foulbrood In Honeybees, Bryan Merrill, Sandra Burnett

Journal of Undergraduate Research

The deadly honey bee disease American Foulbrood (AFB) is caused by the bacterium Paenibacillus larvae. The widespread use of antibiotics to prevent or treat AFB has led to many drug-resistant strains of P. larvae. Bacteriophages can target and destroy specific strains of bacteria and can be used to treat bacterial infections. This study accomplished two main goals. We determined the efficacy of previously isolated P. larvae phages as a treatment for AFB by applying a phage spray to infected beehives. We also isolated P. larvae bacteria from the infected hives we treated and identified phages to better counteract …

How Chemokine Ccl28 Binds To Yersinia Pseudotuberculosis, Jeffrey Moffat, David Erickson

Journal of Undergraduate Research

Chemokines are tiny proteins that play a valuable role in defending our bodies against bacteria and other pathogens. Chemokines are best known for their role in attracting immune cells to areas of infection. Some chemokines, however, have demonstrated the ability to not only recognize pathogens and/or recruit white blood cells, but also to kill various classes of bacteria and fungi¹. One of these antimicrobial chemokines is CCL28.

Histone Modifications And Their Effects On Nucleosome Positioning And Gene Expression, Jordon Ritchie, Steven Johnson

Journal of Undergraduate Research

Nucleosome positioning plays an important role in gene regulation and expression. Nucleosomes consist of DNA-histone interactions that comprise the first order of DNA compaction into chromatin in the cell. Modifications to the histone in the nucleosome have been hypothesized to influence the location of the nucleosome on the DNA and therefore the regulation of the gene the nucleosome is forming on. In our original proposal, we proposed to show the effects that different modifications had on the position of the nucleosome on the DNA and the DNA sequence that had the highest affinity for nucleosome formation given a specific histone …

How Yersinia Pseudotuberculosis Biofilm Formation Is Regulated By Global Regulator Csra, Jeffrey Schachterle, David Erickson

Journal of Undergraduate Research

The bacteria Yersinia pestis is the causative agent of bubonic plague, and its ability to form biofilm in fleas is essential for plague transmission by fleas [1]. Y. pestis recently evolved from Y. pseudotuberculosis (Y. pstb), and the two have nearly identical genomes. Y. pestis forms a biofilm in fleas that is capable of blocking the flea’s feeding. These biofilms are made up of a community of bacteria adhering to a polysaccharide matrix that is made by the hmsHFRS gene products. Y. pstb is capable of infecting fleas, but will not block the flea’s feeding [1]. Since the …

Analysis Of The Adjuvant Effect Of Vitamin D3 In Enhancing Mucosal Immune Responses, Cameron Sargent, Dr. Eric Wilson

Journal of Undergraduate Research

Because skin provides an effective physical barrier, most pathogens that invade the body do so at mucosal sites like the nose and mouth. As such, finding methods of improving mucosal immunity is key to providing greater defense against communicable diseases, the cause of approximately one-quarter of all deaths worldwide [1]. Improving vaccination, the technique in which the body is exposed to a weakened or nonvirulent dosage of a pathogen or toxin to promote an immune response specific to that foreign material, is a potential way of enhancing mucosal immunity. Vaccination has been used for several decades in medicine, nearly eradicating …

A Method Of Introducing Site Specific Mutations Into The Phor Gene Of The E. Coli Chromosome, Cameron Woodward, William Mccleary

Journal of Undergraduate Research

Phosphate intake by Escherichia coli serves as a good model system to study phosphate intake by other bacteria. The pho phosphate uptake system used by E. coli is well conserved in pathogens like Vibrio cholerae (1). To better understand this important mode of phosphate uptake a study was performed to examine the interactions between the phoR and phoU proteins of this system. PhoU interacts with the pstSCAB complex, which brings phosphate into the cell. After communicating with pstSCAB the phoU protein interacts with phoR to tell it if phosphate is present in the environment or not. PhoR has been shown …

Characterizing Dna2 In Model Plant Arabidopsis, Connor Woodward, Brent Nielsen

Journal of Undergraduate Research

Dna2 is a protein that is known to be essential for DNA replication in human and yeast mitochondria. In these organisms it acts as both a helicase and an endonuclease. In the model plant Arabidopsis thaliana an ortholog of Dna2 exists but has never been studied. Two questions were answered in this study. The first question is “What would happen to A. thaliana plants that lacked Dna2?”. The second is “Where is Dna2 localized in plant cells?”

Role Of Epstein-Barr Virus Induced Gene Ii (Ebi2) In Epstein-Barr Virus Infection And B-Cell Chemotaxis, Brian Poole

Journal of Undergraduate Research

The academic objectives of this proposal were met. Using the funding provided by the MEG, we generated data that was used to publish three peer-reviewed journal articles:

Post-Translational Modifications Of Thymidine Kinase 1, Dr. Kim O'Neill

Journal of Undergraduate Research

Thymidine kinase 1 (TK1) is one diagnostic and prognostic marker which has shown promising potential in a variety of solid tumors and hematological malignancies. Unfortunately there have been challenges associated with developing a clinically useful immunoassay which have prevented TK1 from being fully utilized in the clinical setting at present. One of the major goals of this study was to produce a dependable, reproducible, immunoassay to detect TK1 in serum from cancer patients. There have been many attempts at detecting protein or genetic material in the serum or sputum of lung cancer patients but these all have failed due to …

Elucidating A Precise Role For The Small Heat Shock Proteins Cryab And Hspb2 In Cardiac Robustness, Julianne H. Grose

Journal of Undergraduate Research

Evaluation of how well the academic objectives of the proposal were met

• Specific Aim 1: Perform yeast two-hybrid screens on wild type CryAB, R120G CryAB, and HspB2 in order to create a protein-protein interaction network and identify potential substrates.
• Achievements: Large-scale yeast-two hybrid screens were performed on wild type CryAB, R120G CryAB and HspB2 in order to identify their protein-protein interaction networks and to identify putative substrates.
• Specific Aim 2: Validate the protein-protein interaction network via Y2H dependency tests (A), affinity purification from mammalian cells (B) and chaperone activity assays (C).
• Achievements: Y2H dependency tests were performed for all three …

Validation Of An Nbmp2 Mutant Mouse Model, Laura C. Bridgewater

Journal of Undergraduate Research

Work in the Bridgewater Lab over the last several years has focused on elucidating the function of a novel protein we discovered, nBmp2. The initial discovery presenting work performed in cultured cells (rather than whole animals) was published back in 2010 and we subsequently constructed a mutant mouse line in which nBmp2 is disrupted. Much evidence was accumulating to show that the mice have problems with muscle function, neurological function, and immune function, but some fundamental experiments necessary to validate the mouse model had been giving us problems. The absence of that data prevented us from publishing any reports on …