Life Sciences Commons^™

Exploring Secondary Structure In Bacteriophage Programmed Frameshift Elements, Samuel Okabayashi, Sean Mcclory

HON499 projects

Bacteriophages are viruses that infect bacteria and reproduce using host bacterial components. Part of the bacteriophage reproduction is assembly of the tail complex, which requires two assembly chaperone (TAC) proteins. In many phages the TAC’s are produced from a single gene through a non-canonical process called programmed translational frameshifting (PTF). The SEA-PHAGES program has produced hundreds of TAC genes that are accessible through phagesdb, a database of sequenced and annotated phage genomes. The sequences for the TAC gene were gathered from phagesdb and analyzed using ClustalOmega; a multiple sequence alignment (MSA) tool which revealed several positions where total conservation was …

Analyzing The Role Of A Protein Downregulated After Induction Of Filamentous Growth In Candida Albicans, Jazmine Vasquez, Ian Cleary, Derek P. Thomas

McNair Scholars Manuscripts

Candida albicans is a commensal fungus, normally living with its human host, however, it has the ability to cause invasive infection. Candida albicans is the fourth most frequent nosocomial infection affecting a vulnerable immunocompromised population. Candida albicans exhibits different morphologies including yeast, pseudohyphae, and hyphae. The varying morphological potential of this organism is a virulence trait. Because of this, research has focused on what drives activation of hyphal formation as well as what impedes it. During a filamentation assay, a novel observation pertaining to a subgroup of proteins being downregulated early after germination, was made. In this study, we constructed …

9th Annual Postdoctoral Science Symposium, University Of Texas Md Anderson Cancer Center Postdoctoral Association

Annual Postdoctoral Science Symposium Abstracts

The mission of the Annual Postdoctoral Science Symposium (APSS) is to provide a platform for talented postdoctoral fellows throughout the Texas Medical Center to present their work to a wider audience. The MD Anderson Postdoctoral Association convened its inaugural Annual Postdoctoral Science Symposium (APSS) on August 4, 2011.

The APSS provides a professional venue for postdoctoral scientists to develop, clarify, and refine their research as a result of formal reviews and critiques of faculty and other postdoctoral scientists. Additionally, attendees discuss current research on a broad range of subjects while promoting academic interactions and enrichment and developing new collaborations.

Comparison Of The Kinetic Parameters Of Escherichia Coli 0157:H7, Listeria Monocytogenes And Salmonella Typhimurium Derived From The Baranyi And Huang Models In A Chemically Defined Minimal Medium, Jose Isidro Fuentes

LSU Master's Theses

Microbial growth can be characterized by parameters such as lag time, growth rate, and maximum population density at any specific point of time. Mathematical models that predict microbial growth of foodborne pathogens are increasingly used in the food industry as a viable alternative to traditional methods of microbial enumeration. The Baranyi model has been widely used as the primary model of choice by many authors because of its performance and accuracy. The most recently developed Huang model has been less implemented and few comparisons between the Baranyi and Huang models have been made when modeling pathogenic growth. For this research, …

Electrostatically Localized Proton Bioenergetics: Better Understanding Membrane Potential, James Weifu Lee

Chemistry & Biochemistry Faculty Publications

In Mitchell's chemiosmotic theory, membrane potential Δψ was given as the electric potential difference across the membrane. However, its physical origin for membrane potential Δψ was not well explained. Using the Lee proton electrostatic localization model with a newly formulated equation for protonic motive force (pmf) that takes electrostatically localized protons into account, membrane potential has now been better understood as the voltage difference contributed by the localized surface charge density ([H-⁺_L] + ⁿΣ _i=1 [M⁽ⁱ⁺⁾_L]) at the liquid-membrane interface as in an electrostatically localized protons/cations-membrane-anions capacitor. That is, the origin of membrane …

A Rapid Viability And Drug‑Susceptibility Assay Utilizing Mycobacteriophage As An Indicator Of Drug Susceptibilities Of Anti‑Tb Drugs Against Mycobacterium Smegmatis Mc2 155, Gillian Catherine Crowley, Jim O'Mahony, Aidan Coffey, Riona G. Sayers, Paul D. Cotter

Department of Biological Sciences Publications

Background: A rapid in-house TM4 mycobacteriophage-based assay, to identify multidrug resistance against various anti-tuberculosis drugs, using the fast-growing Mycobacterium smegmatis mc² 155 in a microtiter plate format was evaluated, based on phage viability assays. Methods: A variety of parameters were optimized before the study including the minimum incubation time for the drugs, phage and M. smegmatis mc² 155 to be in contact. An increase in phage numbers over 2 h was indicative that M. smegmatis mc² 155 is resistant to the drugs under investigation, however when phage numbers remained static, M. smegmatis mc² 155 found to …

Fungi In A Hot, Dry, Changing World, Miriam I. Hutchinson

Biology ETDs

My doctoral work focused on understanding the reciprocal relationship between fungi and their environment, namely how fungi respond to environmental flux, as well as how fungi can modify and structure their habitats, especially in the context of climate change. As such, I aimed my research on fungi with distinct adaptations to their environmental niches: endophytic fungi that inhabit plant tissue and thermophilic fungi that are capable of growing at the upper temperature limit for eukaryotic life. My research consisted of three studies. First, I investigated the thermophilic species Myceliophthora heterothallica to demonstrate its use as a model organism for efficient …

Developing A Modern Microbiology Laboratory Manual To Enhance Student Learning, Alexander Yonchak

Senior Honors Projects

My project has been addressing the issue of incorporating recent developments in biosafety and pedagogical approaches for lab-courses into our existing educational curriculum by developing a new, modern lab manual aimed at improving experiential learning for introductory microbiology teaching labs. Through researching the most recent safety regulations, industry standards, & guidelines for such teaching labs, my manual clearly delineates learning outcomes to match the skills expected of undergraduates completing degrees within the life sciences. In addition, the lab manual that I have designed has been modernized to incorporate the most recent recommended safety precautions and is written in a user-friendly …

Searching For Megaviruses In Iceland, Delanie Baker

Student Symposium

The proposed Megavirales order comprises members of the previously known nucleocytoplasmic large DNA viruses (NCLDVs). Virus families in the Megavirales order include Poxviridae, Ascoviridae, and the recently explored families of megaviruses infecting free living amoeba such as Mimiviridae, Marseilleviridae, and Pandoraviridae. Megaviruses have been isolated from water and soil samples from Chile, France, India, and the United States. We chose to study the occurrence of megaviruses in Iceland because of the diverse habitats all within one island. No research has been carried out on the presence of megaviruses in Iceland. Samples of water and soil were collected from lava fields, …

A Comparative Analysis Of The Fermentation Capabilities Of Various Bifidobacterium Strains, Ella Oney

Honors Theses

Bifidobacterium is a genus of anaerobic bacteria that are commonly found to inhabit the gastrointestinal tract of many members of the animal kingdom. These microorganisms are adapted to obtain their carbon from the breakdown of complex carbohydrates. Marmosets, a mammal whose gut microbiome is inhabited by high levels of Bifidobacteria, consume gum Arabic as a major part of their diet. The purpose of this experiment is to determine whether Bifidobacterium strains isolated from the guts of marmosets are able to degrade and ferment this complex carbohydrate or one of its main constituents, arabinose. This was accomplished by inoculating isolates of …

Genetic Study Of Checkpoint Defects Of The Mus81-1 Mutant In The Fission Yeast Schizosaccharomyces Pombe, Darlington Osei Abrefa

Browse all Theses and Dissertations

In response to various perturbations of DNA replication, the DNA replication checkpoint is activated in eukaryotes to stimulate a cascade of cellular responses that are crucial for maintaining genome stability and cell survival. Defects in the checkpoint pathway result in mutations and genome instability, which is a hallmark for cancers. This study used a genetic approach to identify a mutation in the MMS (methyl methanesulfonate) and UV-sensitive protein Mus81, a DNA repair enzyme that resolves aberrant DNA structures through the homologous recombination pathway. We show that a single missense mutation, identified in fission yeast mus81-1, causes moderate reduction in the …

The Role Of Cody In Hydrogen Peroxide Tolerance And Biofilm Formation Of Streptococcus Mutans, Kaitlin M. Rioux, Brandaliz Santiago-Narvaez

Honors Program Theses

Streptococcus mutans is the major cariogenic bacterium in the oral cavity. S. mutans causes disease by three main virulence factors: acid production, acid tolerance, and biofilm formation. S. mutans outcompetes various other species in the oral cavity, however it is affected by hydrogen peroxide production by these species. Based on previous findings and this research, hydrogen peroxide is shown to extend the lag phase of S. mutans but does not kill it unless present in extremely high amounts that are generally not produced by commensal species like S. sanguinis and S. gordonii in the oral cavity. CodY is a global …

A Full-Ocean-Depth Rated Modular Lander And Pressure-Retaining Sampler Capable Of Collecting Hadal-Endemic Microbes Under In Situ Conditions, Logan M. Peoples, Matthew Norenberg, David Price, Madeline Mcgoldrick, Mark Novotny, Alexander Bochdansky, Douglas H. Bartlett

OES Faculty Publications

The hadal zone remains one of the least studied environments because of its inaccessibility, in part because of hydrostatic pressures extending to 110 MPa. Few instruments are capable of sampling from such great depths. We have developed a full-ocean-depth-capable lander that can be fit with sampling packages for the collection of still images, video, motile megafauna, and hadal seawater. One payload includes a pressure-retaining sampler (PRS) able to maintain seawater samples under in situ pressure during recovery. We describe the technical specifications of the lander and the PRS and preliminary results from three deployments at depths in excess of 10,700 …

Understanding The Molecular Strategies Of Campylobacter Jejuni For Survival In Amoeba And Chicken., Deepti Pranay Samarth

Graduate Theses and Dissertations

Campylobacter jejuni endure to be major cause of gastroenteritis in humans worldwide. C. jejuni is fastidious in laboratory setup but can cause waterborne infection through contaminated water where none of these fastidious conditions are met. This dissertation presents an assortment of studies focused in reviewing three major factors which could present a helping hand to C. jejuni in its environmental survival viz. i) association with free-living amoebae (FLA) ii) horizontal gene transfer (HGT) contributing towards its genetic diversity iii). Viable but non-culturable (VBNC) state.

Acanthamoeba is a FLA linked to environmental survival of many intracellular pathogens, including C. jejuni. In …

The Gut Microbiome: Is Fecal Matter Microbial Composition A Proxy For Intestinal Microbial Composition In Studies Of The Microbiome, Enique Reyes

All Master's Theses

As many health phenomena seem to be affected directly and indirectly by the microbiome, gut microbiome research has increased in the last decade. Issues such as allergies, cancer, obesity, and other health complications have been shown to be influenced by the microbiome. Most of gut microbiome research is done by collecting and sequencing the DNA of the microbiome of the fecal matter from model organisms or human subjects. Studies that use this method of sample collection and analysis assume that fecal matter microbiomes are similar to intestinal microbiomes, and that it can be used as a proxy. At present, no …

Bacterioplankton Biogeography Of The Mississippi River Basin, Jason Taylor Payne

Electronic Theses and Dissertations

Bacterioplankton are important structural and functional components of river networks yet their biogeographical patterns in these systems are largely unknown. Using Illumina sequencing of the 16S rRNA gene we characterized variation in bacterioplankton community alpha diversity (within-sample richness of operational taxonomic units OTUs) and beta diversity (between-sample differences in composition) (1) along a 1 300-km downstream reach of the Mississippi River (2) over a range of temporal scales in the Lower Mississippi River (LMR) and (3) along cross-sectional transects repeated monthly for six months across the LMR floodplain. Particle-associated assemblages were richer in bacterial OTUs and more productive than free-living …

Six-Nine Months Long Term Culture Of Mouse Bone Marrow Cells Differentiated To Macrophages And Eosinophils, Olena B. Svitlova

Browse all Theses and Dissertations

Mouse models of eosinophil-associated diseases have been used to study the mechanisms of disease pathogenesis. In this study, mouse-derived bone marrow cells were used in long-term (6 and 9 months) cell cultures of differentiated eosinophils and macrophages. IL-5 was used to differentiate the stem cells to eosinophils and GM-CSF was used to propagate macrophages from the bone marrow stem cells. The maximum time period for observing the eosinophil cultures was 252 days which is censurably longer than the 18 days culture period observed by others. The results were assessed by describing the microscopic cell morphology by Wright staining, modified Giemsa …

Enhanced Expression Of Receptor Tyrosine Kinase Mer (Mertk) On Socs3-Treated Polarized Raw 264.7 Anti-Inflammatory M2c Macrophages, Sankhadip Bhadra

Browse all Theses and Dissertations

Macrophages are phagocytic cells located in tissues, organs and even circulated within our body as white blood cells. They are critical in detecting tissue damage and infection. Resident tissue macrophages initiate the signals for inflammation recruiting neutrophils and blood monocytes which mature into macrophages at sites of infection and in the resolution of inflammation. Based on the local cytokine milieu in tissue sites, macrophages may be polarized into pro-inflammatory M1 or anti-inflammatory M2 phenotypes. Receptor tyrosine kinase Mer (MERTK) helps in clearing dead neutrophils and other apoptotic cells from damaged tissue sites preventing chronic inflammation and autoimmune disorders. MERTK aids …

The Effects Of Socs1 And Socs3 Peptide Mimetics On Macrophage Phagocytosis Of Malignant Cells, Tahirah M. Madkhali

Browse all Theses and Dissertations

Macrophages are essential phagocytic cells involved in both innate and adaptive immune systems and play vital roles in the host defense and inflammation. Macrophages have a remarkably high capacity to clear unnecessary cellular materials in interstitial environment through a process called “phagocytosis”, which is affected by many factors including suppressors of cytokine signaling (SOCS). SOCSs are a group of intracellular proteins that downregulate the cytokine signals involved in various JAK/STAT pathways through a negative feedback loop. This study focuses on investigating the effects of SOCS1 and SOCS3 on the phagocytic ability of RAW 264.7 macrophages polarized into M2a with IL-4/IL-13 …

Structural Investigation Of Bcsc: Insight Into Periplasmic Transport During Cellulose Export, William Scott, Joel T. Weadge

Theses and Dissertations (Comprehensive)

A biofilm can be defined by a community of microbes coexisting within a self-produced protective polymeric matrix. Exopolysaccharide (EPS) is a key component in biofilms and a contributor to their virulence and pathogenicity. The cellulose bacterial synthesis complex is one such EPS system that is found in many Enterobacteriaceae,including Escherichia coli and Salmonella spp., and is responsible for the production and secretion of the EPS cellulose. BcsC is the periplasmic protein responsible for the export of the exopolysaccharide cellulose and was the focus of this research. Sequence homology comparisons and structural predictions between BcsC, and the previously characterized alginate …

Xylan Metabolism By Caulobacter Crescentus, Viet Bui

Masters Theses

Bacteria present unique opportunities to explore the molecular mechanisms of nutrient acquisition processes at single cell level under various experimental conditions. Caulobacter crescentus is a gram-negative oligotrophic environmental bacterium with adaptive physiological responses, such as slow growth or complete arrest of cell cycle, presence of sessile and motile progenies with the sessile cells growing stalk to enhance nutrient uptake for growth in low-nutrient conditions. Details of plant polysaccharide-derived carbon compound, such as cellobiose, maltose, and xylose utilization by C. crescentus can be found but molecular details or mechanisms of polysaccharide utilization, such as xylan, has not been reported. Database analyses …

Riparian Zone Soil Microbial Community Dynamics: Interactions With Nutrient Loadings, James Bannister

Theses and Dissertations (Comprehensive)

Riparian zones are a type of wetland described as the interface between land and a body of water such as a river or stream. Riparian zones are effective buffers against anthropogenic pollutants and nutrient loads from non-point sources that can greatly diminish water quality. Riparian zones can host a variety of plant species and associated microbial communities. The combined biological processes of plants, bacteria, and arbuscular mycorrhizal fungi (AMF) are key to nutrient cycling and nutrient removal in riparian zones. As such, understanding the factors that influence them is critical for watershed management. This research is targeted at obtaining a …