Microbiology Commons^™

Efficacy Of Ultraviolet Radiation To Control Lactic Acid Bacteria In Wine Must, Brian D. Williams

All Master's Theses

The use of shortwave ultraviolet (UV_c) radiation to control lactic acid bacteria (LAB) in wine production was studied. A simulated wine sterilizer was built using a commercially sourced ultraviolet (UV) sterilizer commonly used in aquariums and ponds. After growing cultures in test tubes, samples of five different species of LAB were introduced into white grape juice adjusted for brix and pH to match that of wine must commonly found in the Yakima Valley American Viticultural Area. The mixture was then agitated and allowed time to evenly distribute the bacteria throughout the juice. The juice was sent through the …

The Effect Of O Antigen Loss On The Protein Composition And Inflammatory Response Elicited By Klebsiella Pneumoniae, Bethaney Cahill

UNF Graduate Theses and Dissertations

Klebsiella pneumoniae is a Gram-negative pathogen associated with numerous infections. Like all Gram-negative bacteria, K. pneumoniae naturally release outer membrane vesicles (OMVs) during all stages of cellular growth. OMVs are composed of the outer membrane components such as lipopolysaccharide (LPS) and outer membrane proteins and contain cytosolic and periplasmic proteins in the lumen. K. pneumoniae is often found to lack an O antigen. The absence of the O antigen has been reported to alter the protein content of the membrane which may further alter the immune response elicited by K. pneumoniae. Therefore the purpose of this study was to …

Purification And Characterization Of Bcsc; An Integral Component Of Bacterial Cellulose Export, Emily D. Wilson Ms

Theses and Dissertations (Comprehensive)

Biofilms are a growing concern in the medical field due to their increased resistance to antibiotics. When found in a biofilm, bacteria can have antibiotic resistance 10-1000 times that of their planktonic counterparts. Therefore, it is important to study the formation of biofilms. Cellulose biofilms are formed by Enterobacteriaceae, such as many Escherichia coli and Salmonella spp. strains. Biofilms provide these species with benefits including antimicrobial protection, development of bacterial communities, promotion of DNA exchange, uptake of nutrients, and, in the case of cellulose biofilms, immune system evasion. Cellulose biofilms are controlled by the Bacterial cellulose synthesis (Bcs) complex located …

Exploring The Role Of Intracellular Aminopeptidases In Staphylococcus Aureus Pathogenesis, Devon Nicole Marking

USF Tampa Graduate Theses and Dissertations

Staphylococcus aureus is a remarkably pathogenic bacterium that is widely prevalent among the human population. It is the leading agent of skin and soft tissue infections, and is also responsible for causing an array of severe and life threatening diseases. The invasiveness of the pathogen, coupled with increasing antibiotic resistance seen for S. aureus infections, makes this bacterium a prominent public health concern. The extended pathogenicity of S. aureus is largely due to its repertoire of virulence factors, which are typically characterized by being bound to the cell wall, or secreted into the extracellular environment. Previously, our lab identified a …

Melatonin And Neurogenesis: A Comparative Study Of The Efficacy Of Melatonin, Its Precursors, And L-Dopa On Neural Stem Cell Metabolism In Human Adult Neurospheres, Omar Heriba

HIM 1990-2015

Human neurosphere stem cells offer promising potential for the treatment of neurodegenerative diseases. Their well characterized multi-potency of differentiating into neurons, astrocytes, and oligodendrocytes when exposed to the optimum exogenous growth factors make them an exciting area of study (38). Finding novel endogenous methods of modulating stem cell metabolism will allow for the safer treatment of various brain disorders (34). In this experiment, melatonin, N-acetylserotonin, L-tryptophan, and L-DOPA are added in three different concentrations to neurospheres suspended in HNSC/GBM media with less than optimal concentrations of exogenous epidermal growth factor (EGF) and fibroblast growth factor (FGF). The alamarBlue assay (resazurin) …

Characterization And Role Of Msaabcr In Biofilm Development And Virulence In Staphylococcus Aureus, Gyan Sundar Sahukhal

Dissertations

Community-acquired, methicillin-resistant Staphylococcus aureus strains often cause localized infections in immune-compromised hosts, but some strains show enhanced virulence leading to severe infections even among healthy individuals with no predisposing risk factors. The genetic basis for this enhanced virulence has yet to be determined. S. aureus possesses a wide variety of virulence factors, the expression of which is carefully coordinated by a variety of regulators. Several virulence regulators have been well characterized, but others have yet to be thoroughly investigated. Previously, the msa gene as a regulator of several virulence genes, biofilm development, and antibiotic …

Using The Yeast Two-Hybrid System To Determine The Function Of Parkin E3 Ubiquitin Ligase, Vanessa Nguyen

HIM 1990-2015

Parkin is a cytosolic E3 ubiquitin ligase that is recruited to the mitochondria during cellular stress and has been suggested to be involved in a variety of biological processes such as mitophagy. The recruitment of Parkin (PARK2) to the mitochondria is dependent upon the kinase activity and the accumulation of PINK1 on damaged mitochondria. Mutations in either PINK1 or Parkin genes disrupt this protective pathway and lead to the accumulation of damaged mitochondria. From a clinical standpoint, mutations in the PARK2 gene have been associated with the progression and onset of autosomal recessive juvenile parkinsonism. Without the presence of a …

Host Cell Death In Legionella Pneumophila Pathogenesis And Immunity, Wenhan Zhu

Open Access Dissertations

Legionella pneumophila is an intracellular pathogen that causes a severe, atypical pneumonia termed Legionnaires' disease. Upon entering the host cell, L. pneumophila resides in a membrane-bound vacuole, in which the bacterium evades lysosomal fusion and replicates. The establishment of the vacuole requires the Dot/Icm (Defect in organelle trafficking/ intracellular multiplication) transport system, which translocates a large number of substrates into host cells to re-orchestrate various cellular processes, such as intracellular trafficking, protein synthesis and host cell death pathways. Therefore, a key step in understanding the biology of Legionella is to dissect the mechanisms of action of the Dot/Icm substrates. By …

Large-Scale Identification Of Chemically Induced Mutations In Drosophila Melanogaster, Nele A Haelterman, Lichun Jiang, Yumei Li, Vafa Bayat, Hector Sandoval, Berrak Ugur, Kai Li Tan, Ke Zhang, Danqing Bei, Bo Xiong, Wu-Lin Charng, Theodore Busby, Adeel Jawaid, Gabriela David, Manish Jaiswal, Koen J T Venken, Shinya Yamamoto, Rui Chen, Hugo J Bellen

Faculty, Staff and Students Publications

Forward genetic screens using chemical mutagens have been successful in defining the function of thousands of genes in eukaryotic model organisms. The main drawback of this strategy is the time-consuming identification of the molecular lesions causative of the phenotypes of interest. With whole-genome sequencing (WGS), it is now possible to sequence hundreds of strains, but determining which mutations are causative among thousands of polymorphisms remains challenging. We have sequenced 394 mutant strains, generated in a chemical mutagenesis screen, for essential genes on the Drosophila X chromosome and describe strategies to reduce the number of candidate mutations from an average of …

Mechanisms And Molecular Biology Of Major Tumor Suppressors, Brienne E. Engel

USF Tampa Graduate Theses and Dissertations

This dissertation is devoted to the study of the molecular biology of major tumor suppressors, defined as those that prevent the cellular processes identified as the hallmarks of cancer. Specifically, the major tumor suppressors pRb and STK11 are explored in the context of osteosarcoma and lung cancer, respectively.

RB1 was the first tumor suppressor gene discovered. Over four decades of work have revealed that the Rb protein (pRb) is a master regulator of biological pathways influencing virtually every aspect of intrinsic cell fate including cell growth, cell-cycle checkpoints, differentiation, senescence, self-renewal, replication, genomic stability and apoptosis. While these many processes …

Role And Regulation Of Snon/Skil And Plscr1 Located At 3q26.2 And 3q23, Respectively, In Ovarian Cancer Pathophysiology, Madhav Karthik Kodigepalli

USF Tampa Graduate Theses and Dissertations

Ovarian cancer is one of the most common causes of gynecological cancer related deaths in women. In 2014, the estimated number of deaths due to ovarian cancer is 14,270 with occurrence of over 22, 240 new cases (National Cancer Institute, http://seer.cancer.gov/statfacts/html/ovary.html). Despite improvement in treatment strategies, the 5-year survival rate is still below 50% mainly due to chemoresistance and relapse. Amplification of chromosomal region 3q26 is a common characteristic in various epithelial cancers including ovarian cancer. This region harbors various oncogenes including the TGFβ signaling mediators EVI1 and SnoN/SkiL, PKCι and PIK3CA amplified at 3q26.2 and 3q26.3, respectively, in ovarian …

Nack Is An Integral Component Of The Notch Transcriptional Activation Complex And Is Critical For Development And Tumorigenesis, Kelly L Weaver, Marie-Clotilde Alves-Guerra, Ke Jin, Zhiqiang Wang, Xiaoqing Han, Prathibha Ranganathan, Xiaoxia Zhu, Thiago Dasilva, Wei Liu, Francesca Ratti, Renee M Demarest, Cristos Tzimas, Meghan Rice, Rodrigo Vasquez-Del Carpio, Nadia Dahmane, David J Robbins, Anthony J Capobianco

Rowan-Virtua School of Osteopathic Medicine Departmental Research

The Notch signaling pathway governs many distinct cellular processes by regulating transcriptional programs. The transcriptional response initiated by Notch is highly cell context dependent, indicating that multiple factors influence Notch target gene selection and activity. However, the mechanism by which Notch drives target gene transcription is not well understood. Herein, we identify and characterize a novel Notch-interacting protein, Notch activation complex kinase (NACK), which acts as a Notch transcriptional coactivator. We show that NACK associates with the Notch transcriptional activation complex on DNA, mediates Notch transcriptional activity, and is required for Notch-mediated tumorigenesis. We demonstrate that Notch1 and NACK are …

Transcriptional Regulation Of Sinorhizobium Meliloti Cell Cycle-Related Genes In The Δcbra Mutant And Root Nodules Of Medicago Sativa, Corey S. Hazekamp

Graduate Masters Theses

Sinorhizobium meliloti is a Gram-negative alphaproteobacterium and nitrogen-fixing symbiont, which undergoes a novel cell cycle modification during its' host-microbe interaction. I intend to monitor the transcriptional regulation of cell cycle-related genes during free-loving growth, in addition to monitoring their expression during symbiosis. Using genes known to be regulated by CtrA in C. crescentus or predicted to be regulated by CtrA in S. meliloti, I aim to show how certain cell cycle genes are regulated in S. meliloti. In C. crescentus, CtrA acts as a transcription factor that is active when phosphorylated and inactive when not phosphorylated. In …

Antiviral Responses In Mouse Embryonic Stem Cells: Differential Development Of Cellular Mechanisms In Type I Interferon Production And Response, Ruoxing Wang

Dissertations

Embryonic stem cells (ESCs) have been recognized as a promising cell source for regenerative medicine. Intensive research over the past decade has led to the possibility that ESC-derived cells will be used for the treatment of human diseases. However, increasing evidence indicates that ESC-derived cells generated by the current differentiation methods are not fully functional. It is recently recognized that ESC-derived cells lack innate immunity to a wide range of infectious agents and inflammatory cytokines. When used in patients, ESC-derived cells would be placed in wounded sites that are exposed to various pathogens and inflammatory cytokines; therefore, their viability and …

Energy Stress Causes Chaperones To Assemble Into Cytoplasmic Complexes, Kimberly J. Cope

Dissertations and Theses (Open Access)

The majority of proteins require molecular chaperones to assist their folding into tertiary and quaternary structures. Certain stresses can compromise the weak hydrophobic forces responsible for these structures and lead to protein unfolding, misfolding, and aggregation. Aggregates of proteins are hallmarks of devastating diseases such as Alzheimer’s, Parkinson’s, and Huntington’s diseases. Fortunately, bacteria, plants, and fungi have a potent disaggregase, named Hsp104 in Saccharomyces cerevisiae. Recently, heat-induced aggregates, termed Q-bodies, were found to contain three molecular chaperones: Hsp70, Hsp104, and Hsp42. Their coalescence from small puncta into larger inclusions required Hsp104. During glucose deprivation, a stress that isn’t known to …

Characterizing The Response Of Multidrug-Resistant Klebsiella Pneumoniae Species To The Application Of A Phage Cocktail, Steven Liu

Symposium

Project Summary: The application of bacteriophages to treat bacterial infections is known as phage therapy, which takes advantage of bacteriophage’s natural ability to infect and lyse bacterial hosts. Phages have been shaped by billions of years of evolution to be highly specialized deliverers of bactericidal agents to the cytoplasm of their target bacteria. Ever since discovery of bacteriophages in 1915, phage therapy was recognized as a potentially powerful tool for eliminating bacterial infections. The effectiveness of phage therapy can be increased by creating a mixture of multiple phages to target a wider variety of bacterial strains. Furthermore, phage therapy has …

Structure And Function In Bacteriophage Phi6, James Carpino

Dissertations, Theses, and Capstone Projects

The present study of bacteriophage Phi6 has been preceded by a great number of exploratory studies of its structure and function, and these studies have formed a basis for Phi6's development into a model organism. In this study, two aspects of the model organism have been examined. 1. There are several uncharacterized and presumed untranslated regions (UTRs) in Phi6's 13.3 kilobase-pair dsRNA genome. I examined the impact of specific modification to the 3' UTR of the small segment of bacteriophage Phi6. I determined that modification to the purported UTR of the small segment resulted in severe fitness costs, supporting a …

Genetic Basis For The Virulence Of Enterohemorrhagic Escherichia Coli Strain Tw14359, Jason Kyle Morgan

USF Tampa Graduate Theses and Dissertations

Enterohemorrhagic Escherichia coli (EHEC) is a virulent pathotype of E. coli that is associated with major outbreaks of hemorrhagic colitis and the life-threatening kidney disease hemolytic uremic syndrome. For successful host colonization and attachment to the intestinal mucosa, EHEC requires the locus of enterocyte effacement (LEE) pathogenicity island, which encodes a type III secretion system (TTSS) responsible for secreting and translocating effector proteins into host colonocytes. Regulation of the LEE is primarily directed through the first operon, LEE1, encoding the locus encoded regulator (Ler), and occurs through the direct and indirect action of several regulators. The 2006 U.S. spinach outbreak …

Functional Analysis Of Cytosolic Hsp70 Nucleotide Exchange Factor Networks In Yeast, Jennifer Lynn Abrams

Dissertations and Theses (Open Access)

The Hsp70 class of molecular chaperones play critical roles in protein homeostasis via an ATP-dependent folding cycle. Cytosolic Hsp70s in the budding yeast Saccharomyces cerevisiae, Ssa and Ssb, interact with up to three distinct nucleotide exchange factors (NEFs) homologous to human counterparts; Sse1/Sse2/HSP110, Fes1/HspBP1, and Snl1/Bag1. In an effort to understand the differential functional contributions of the cytosolic NEFs to protein homeostasis (“proteostasis”), I carried out comparative genetic, biochemical and cell biological analyses. For these studies, I developed protocols to monitor protein disaggregation and reactivation in a near real-time coupled assay that revealed the importance of aggregate dynamics in the …

Determining The Presence Of Carbapenem Antibiotic Resistance In Clinical Isolates, Fidelis Uzoma Enyinnaya

UNLV Theses, Dissertations, Professional Papers, and Capstones

Carbapenems are β-lactam antibiotics reserved for the treatment of severe microbial infections, especially those targeting the Enterobacteriaceae. Introduced in the 1980s, carbapenems have been used successfully in hospitals, and in the 1990s resistance was discovered. Carbapenem resistance is conferred through the production of carbapenemases. In the U.S., the most common carbapenemase is Klebsiella pneumoniae carbapenemase (KPC). In 2012, the National Healthcare Safety Network reported a carbapenem resistance rate of 13.0% among Klebsiella pneumoniae infections, and indicated that the mortality rate associated with carbapenem resistant Enterobacteriaceae (CRE) infections ranged from 48.0-71.9%. According to the Food and Drug Administration (FDA), carbapenem resistance …

Characterization Of Ftsa-Ftsn Interaction During Escherichia Coli Cell Division, [email protected] K. Busiek

Dissertations and Theses (Open Access)

Division of a bacterial cell into two equal daughter cells requires precise assembly and constriction of the division machinery, or divisome. The Escherichia coli divisome includes nearly a dozen essential cell division proteins that assemble at midcell between segregating sister chromosomes. FtsZ, a homolog of eukaryotic tubulin, is the first essential cell division protein to localize at midcell where it polymerizes into a ring-shaped scaffold (Z ring). Establishment of the Z ring is required for recruitment of downstream cell division proteins including FtsA, a cytoplasmic protein that tethers the Z ring to the inner membrane. Following localization of FtsA and …

Clpxp Modulates Cell Growth And Morphology In Cell Shape Mutants Of E.Coli, Ryann Murphy

Senior Honors Projects

ClpXP modulates cell growth and morphology in cell shape mutants of E. coli

Ryann Murphy¹ and Jodi L. Camberg¹

¹University of Rhode Island, Department of Cell and Molecular Biology, Kingston, RI, 02881

Penicillin Binding Proteins (PBPs) are a family of prokaryotic membrane proteins named for their propensity to bind the antibiotic penicillin and are involved in remodeling and deposition of peptidoglycan. In wild type Escherichia coli cells, the uniform rod shape is conserved across generations. E.coli cells containing multiple deletions of Low Molecular Weight (LMW) PBPs exhibit irregular shapes. LMW PBP5 (dacA) is a potential …

Structure-Based Design Of Novel Inhibitors And Ultra High Resolution Analysis Of Ctx-M Beta-Lactamase, Derek Allen Nichols

USF Tampa Graduate Theses and Dissertations

The emergence of CTX-M class-A extended-spectrum β-lactamases, which confer resistance to second and third-generation cephalosporins, poses a serious health threat to the public. CTX-M β-lactamases use a catalytic serine to hydrolyze the β-lactam ring. Specifically, the hydrolysis reaction catalyzed by CTX-M β-lactamase proceeds through a pre-covalent complex, a high-energy tetrahedral acylation intermediate, a low-energy acyl-enzyme complex, a high-energy tetrahedral deacylation intermediate after attack via a catalytic water, and lastly, the hydrolyzed β-lactam ring product which is released from the enzyme complex. The crystallographic structure of CTX-M at sub-angstrom resolution has enabled us to study enzyme catalysis as well as perform …

Section Abstracts: Biology With Microbiology And Molecular Biology

Virginia Journal of Science

Abstracts of the Biology with Microbiology and Molecular Biology Section for the 92nd Annual Meeting of the Virginia Academy of Science, May 13-15, 2014, Virginia Commonwealth University, Richmond, Virginia

The Effects Of Lipoxin A4 (Lxa4) On Neutrophil Biology In Sepsis, Benedict Wu

Graduate School of Biomedical Sciences Theses and Dissertations

During sepsis, neutrophils are inappropriately activated and have prolonged lifespans, thus becoming dysfunctional. Excessive neutrophil activation can lead to tissue injury while neutrophil dysfunction can lead to decreased free radical production and reduced phagocytosis, preventing the host from clearing preexisting infections. Lipoxin A4 (LXA4) is a specialized pro-resolution mediator which reduces neutrophil migration and expression of proinflammatory mediators. Intact neutrophil functions are critical for the host to efficiently clear invading pathogens. The effects of LXA4 on neutrophil function in sepsis have not been established. Using the cecal ligation and puncture (CLP) model of sepsis, LXA4 administered 1 h after sepsis …

Nuclear Import And Interactions Of Potato Yellow Dwarf Virus Nucleocapsid, Matrix, And Phosphoprotein, Gavin Lloyd Franklin Anderson

Theses and Dissertations--Plant Pathology

Potato yellow dwarf virus (PYDV) is the type species of the genus Nucleorhabdovirus and, like all members of this genus, replication and morphogenesis occurs inside the nuclei of infected cells. Protein localization prediction algorithms failed to identify a nuclear localization signal (NLS) in PYDV nucleocapsid (N) protein, although PYDV-N has been shown to localize exclusively to the nucleus when expressed as a green fluorescent protein (GFP):N fusion in plant cells. Deletion analysis and alanine-scanning mutagenesis identified two amino acid motifs, ⁴¹⁹QKR⁴²¹ and ⁴³²KR⁴³³, that were shown to be essential for nuclear import and interaction with …

Ether Bridge Formation And Chemical Diversification In Loline Alkaloid Biosynthesis, Juan Pan

Theses and Dissertations--Plant Pathology

Loline alkaloids, found in many grass-Epichloë symbiota, are toxic or feeding deterrent to invertebrates. The loline alkaloids all share a saturated pyrrolizidine ring with a 1-amine group and an ether bridge linking C2 and C7. The steps in biosynthesis of loline alkaloids are catalyzed by enzymes encoded by a gene cluster, designated LOL, in the Epichloë genome. This dissertation addresses the enzymatic, genetic and evolutionary basis for diversification of these alkaloids, focusing on ether bridge formation and the subsequent modifications of the 1-amine to form different loline alkaloids.

Through gene complementation of a natural lolO mutant and comparison …

Characterization Of Ns1 Sumoylation And Its Effect On Influenza A Viral Infection, Katherine Anne Meraz

Open Access Theses & Dissertations

Influenza virus is a contagious respiratory virus responsible for seasonal epidemics and several catastrophic pandemics in the last century. Its genome is comprised of negative sense, single-stranded RNA and, after entering the cell, it is capable of hijacking the host cellular machinery for reproducing its own genetic material. The activation of cellular defenses against influenza viral infection are triggered upon viral entry and help regulate the course of viral infection. This study focused on the interplay between the influenza A virus and the cellular SUMOylation system during viral infection. The first part of this Dissertation deals with the relevance of …

The Sumoylation Of The Non-Structural Protein 1 Of The Influenza A Virus Plays A Dual Role During Viral Infection, Jason Michael Chacon

Open Access Theses & Dissertations

The potential for a highly pathogenic influenza pandemic remains a concern for global health. The ability of the influenza virus to undergo antigenic shift and genetic drift give circulating strains of influenza the high probability of developing resistance to current antiviral therapies. Emerging strains of higher virulence, to which the infected person has not had any previous exposure to viral antigens, pose a greater threat of serious illness and death. Currently, there is no antiviral therapy that is effective against all strains of influenza, emphasizing the need to develop new strategies that target cellular systems required for viral replication to …

The Role Of Intestinal Sweet Taste Receptors (Strs) In The Regulation Of Glucose Absorption: Effects Of Short Term High Sucrose Diet (Hsd), Tania Hussain

HIM 1990-2015

Sweet taste receptors are primarily found in the oral cavity of the mammalian species. However, recent studies have shown that sweet taste receptors can be found in extraoral tissues such as the pancreas, intestines, and adipose tissue. Our lab has previously found that sweet taste receptors are down-regulated on the pancreas in the presence of high plasma glucose levels. In order to assess the possibility that sweet taste receptors respond to high levels of glucose by suppressing its expression, we wanted to see if they reacted similarly on the intestines. We found that intestinal sweet taste receptors are down regulated …