Microbiology Commons^™

Role Of Regulatory T Cells In The Development And Progression Of Lyme Disease In Balb/C Mice, Kaitlyn Nielsen

Theses and Dissertations

Lyme disease, caused by Borrelia burgdorferi, is an increasingly important public health concern, with tens of thousands of new cases being diagnosed each year, even in previously non-endemic areas. It is known that symptoms of Lyme disease are caused by an inflammatory immune response initiated to aid in clearance of the pathogen. Left unchecked, these inflammatory responses can potentially increase tissue damage, leading to increased disease severity. Mechanisms responsible for the control of the inflammatory response to infection with B. burgdorferi are not entirely understood. Evidence exists that regulatory T (Treg) cells, a population of Foxp3-expressing CD4+ T cells known …

Development Of Indicators For Human Fecal Pollution Using Deep-Sequencing Of Microbial Communities, Shuchen Feng

Theses and Dissertations

The gut microbiome is shaped by both host physiology and environmental factors, which results in unique communities that contain certain members specific to a host. Microbial source tracking (MST) methods that rely on host-specific fecal microorganisms have been applied to detect human fecal pollution over the past two decades. The most common approach uses quantitative polymerase chain reaction (qPCR) to amplify certain sequences of these microorganisms, or human fecal markers. To date, most bacterial human fecal markers have focused on the HF183 cluster within the genus Bacteroides. However, cross-reactions with animals or variable Bacteroides abundance in humans have been found. …

Mechanism Of Anti-Virulence Compound 187r Inhibiting Pseudomonas Aeruginosa Type Iii Secretion System, Liwei Fang

Theses and Dissertations

Antibiotics have been widely used for treating bacterial infectious diseases. However, the rapidly emerging of antibiotic resistance has dramatically decreased the efficacy of antibiotics and poses a serious worldwide crisis. In addition, the cell components serving as antibiotics’ targets are conserved in many different bacterial species, as a result, antibiotic treatments disrupt the host microbiota and negatively influence the hosts health condition. Therefore, new alternative strategies for fighting infectious diseases without causing antibiotic resistance and disturbing the host microbiota are needed. Type 3 secretion system (T3SS) is a highly conserved virulence factor presents in many different Gram-negative pathogens. It is …

Exploring Primitive Legume Symbiosis Using Chamaecrista Fasciculata As A Model, Zachary E. Zawada

Theses and Dissertations

Legumes form symbiotic associations with diazotrophs collectively termed “rhizobia” leading to the formation of nodules and N2-fixation and contribute significant amounts of fixed N to agricultural and natural environments. The mechanisms of nodulation and N2-fixation are extensively studied using model legumes that belong to the Papilionoideae, in which nodulation is widespread and advanced. In contrast, very little is known about the mechanisms of nodulation and N2-fixation in in basal Caesalpinioideae subfamily in which nodulation is rare. The nodulating caesalpiniod legume Chamaecrista fasciculata is widespread in North America and is suggested as a complementary model to study legume nodulation because of …

Flavobacterium Gliding Motility: From Protein Secretion To Cell Surface Adhesin Movements, Joseph Johnston

Theses and Dissertations

Flavobacterium johnsoniae exhibits rapid gliding motility over surfaces. At least twenty genes are involved in this process. Seven of these, gldK, gldL, gldM, gldN, sprA, sprE, and sprT encode proteins of the type IX protein secretion system (T9SS). The T9SS is required for surface localization of the motility adhesins SprB and RemA, and for secretion of the soluble chitinase ChiA. This thesis demonstrates that the gliding motility proteins GldA, GldB, GldD, GldF, GldH, GldI and GldJ are also essential for secretion. Cells with mutations in the genes encoding any of these seven proteins had normal levels of gldK mRNA but …

Analysis Of Genes Involved In Metal Resistance And Cytochrome C Maturation In Shewanella Oneidensis Mr-1, Rini Banerjee

Theses and Dissertations

Metals play crucial roles in many cellular processes where they form active centers of metabolic enzymes or participate in electron transfer reactions during respiration. At high concentrations, metals can be toxic and result in the formation of reactive oxygen species and protein denaturation. Bacteria have evolved homeostasis systems to maintain intracellular concentrations of various metals and avoid their toxic effects. The aim of this project is to identify and characterize metal homeostasis systems in the metal reducer Shewanella oneidensis MR-1. This bacterium can use metals and radionuclides as electron acceptors during anaerobic respiration and is therefore a good candidate for …

Understanding The Link Between Chemotaxis And Biofilm Dispersion Systems In Pseudomonas Aeruginosa, Kayla Audenia Simanek

Theses and Dissertations

The opportunistic pathogen P. aeruginosa forms biofilms during chronic lung infections in cystic fibrosis patients, contributing to morbidity and mortality. Not only are biofilms antibiotic resistant but dispersal may release pathogenic bacteria throughout the body. Previous research discovered a novel interaction between DipA, a phosphodiesterase that promotes biofilm dispersal, and ParP, which localizes chemosensory clusters and has AIF (array integration and formation) domain homology to CheA and CheW of the chemotaxis system. This research was focused on further deciphering the role of ParP’s AIF domain in mediating the interactions between DipA and CheA by using a bacterial two hybrid system. …

Understanding The Link Between Chemotaxis And Biofilm Dispersion Systems In Pseudomonas Aeruginosa, Kayla Audenia Simanek

Theses and Dissertations

The opportunistic pathogen P. aeruginosa forms biofilms during chronic lung infections in cystic fibrosis patients, contributing to morbidity and mortality. Not only are biofilms antibiotic resistant but dispersal may release pathogenic bacteria throughout the body. Previous research discovered a novel interaction between DipA, a phosphodiesterase that promotes biofilm dispersal, and ParP, which localizes chemosensory clusters and has AIF (array integration and formation) domain homology to CheA and CheW of the chemotaxis system. This research was focused on further deciphering the role of ParP’s AIF domain in mediating the interactions between DipA and CheA by using a bacterial two hybrid system. …

Diverse Microbial Communities Hosted By The Model Carnivorous Pitcher Plant Sarracenia Purpurea: Analysis Of Both Bacterial And Eukaryotic Composition Across Distinct Host Plant Populations, Jacob J. Grothjan, Erica B. Young

Biological Sciences Faculty Articles

Background. The pitcher plant Sarracenia purpurea supplements nutrient acquisition through carnivory, capturing insect prey which are digested by a food web community of eukaryotes and bacteria. While the food web invertebrates are well studied, and some recent studies have characterized bacteria, detailed genetic analysis of eukaryotic diversity is lacking. This study aimed to compare eukaryotic and bacterial composition and diversity of pitcher communities within and between populations of host plants in nearby but distinct wetland habitats, and to characterize microbial functions across populations and in comparison with another freshwater community.

Methods. Pitcher fluid was sampled from the two …