Bacteriology Commons^™

A Systems Biology Approach For Predicting Essential Genes And Deciphering Their Dynamics Under Stress In Streptococcus Sanguinis, Fadi El-Rami

Theses and Dissertations

Infectious diseases are the top leading cause of death worldwide. Identifying essential genes, genes indispensable for survival, has been proven indispensable in defining new therapeutic targets against pathogens, major elements of the minimal set genome to be harnessed in synthetic biology, and determinants of evolutionary relationships of phylogenetically distant species. Thus, essentiality studies promise valuable revenues that can decipher much of biological complexities.

Taking advantage of the available microbial sequences and the essentiality studies conducted in various microbial models, we proposed a framework for the prediction of essential genes based on our experimentally verified knowledge of the pathways involved in …

Come Fly With Me: Using Amixicile To Target Periodontal Pathogens And Elucidating The Innate Immune Response In Drosophila Melanogaster, Kathryn Sinclair

Theses and Dissertations

Periodontal diseases (PD) affect 46% of American adults over age 30. These diseases cause symptoms including bleeding and swelling of the gums, bone resorption, and tooth loss, that affect quality of life and have a high economic burden. Periodontal diseases are caused by an imbalance in the oral microbiome, from a healthy state that contains anti-inflammatory commensals like Streptococcus gordonii and mitis, to a diseased state that has pro-inflammatory anaerobic pathogens including Porphyromonas gingivalis, Prevotella intermedia, Fusobacterium nucleatum, and Tannerella forsythia. The latter initiate disease progression in the oral cavity. However, it’s the host immune …

The Role Of The Dosage Compensation Complex As A Pathway For Spiroplasma To Induce Male Lethality In Drosophila Melanogaster, Becky Cheng

CMC Senior Theses

Drosophila melanogaster and many other insects harbor intracellular bacterial symbionts that are transmitted vertically from infected host mothers to their offspring. Many of these bacteria alter host reproductive developmental processes in order to increase their transmission success. For example, Spiroplasma, a spirochete that naturally infects D. melanogaster, selectively kills males during mid-embryogenesis while sparing females. Previous studies suggested that Spiroplasma interacts genetically with the male-specific dosage compensation pathway, which causes ~2-fold up-regulation of most genes located on the male’s single X chromosome so that their expression matches the levels found in females who have two Xs. To further …

Antifungal Genome Mining And Genetics In Filamentous Actinomycete Bacteria Isolated From Local Soils, Jacob Alex, Kevin Lou, Bilal Makhdoom

Undergraduate Research Symposium Posters

Actinomycetes are gram positive, filamentous bacteria that produce useful antibiotics, antitumor agents, and agricultural products. A series of enrichments were undertaken to isolate actinomycetes from local soils, varying enrichment media, antibacterials, and soil treatments (including heat and CaCO3). Isolates were characterized by 16S rDNA sequencing, phenotypic and morphological observations, and antibiotic production. The genetic tractability of select isolates was analyzed using a panel of integrating vectors derived from ɸC31, ɸBT1, and OzzyJ phage using intergeneric conjugation. Further, a semi-degenerate multiplex PCR assay to detect ɸBT1 genomic integrants was designed and tested for the first time. Finally, PCR screens were used …

Role Of Intracellular Growth During The Gastrointestinal Stage Of Listeria Monocytogenes Infection, Grant Steven Jones

Theses and Dissertations--Microbiology, Immunology, and Molecular Genetics

Listeria monocytogenes is a facultative intracellular bacterium that causes foodborne disease in humans. L. monocytogenes invade the gut mucosa and then disseminate, causing systemic infections associated with high mortality rates in immunocompromised individuals. It is unknown how L. monocytogenes traffic to the mesenteric lymph nodes, which represent an important bottleneck for systemic spread. In addition, little is known about the gastrointestinal stage of infection due to the general resistance of mice to oral infection with L. monocytogenes. Our laboratory developed a novel foodborne mouse model of listeriosis utilizing a murinized strain of L. monocytogenes to investigate the gastrointestinal stage …

Structure-Function Investigation Of Proteins Involved In Cellulose Biosynthesis By Escherichia Coli, Thomas Brenner

Theses and Dissertations (Comprehensive)

Bacteria thrive within multicellular communities called biofilms consisting of a self-produced matrix. Biofilm matrices improve bacterial adherence to surfaces while creating a barrier from host immune responses, disinfectants, antibiotics and other environmental factors. Persistent colonization by the widely distributed pathogens, Escherichia coli and Salmonella spp., has been linked to production of biofilms composed of the exopolysaccharide cellulose. Cellulose-containing biofilms are also important to Acetobacter, Sarcina, Rhizobium and Agrobacterium species to form symbiotic and pathogenic interactions. In Enterobacteriaceae, two operons (bcsABZC and bcsEFG) are proposed to encode for proteins that form a cellulose biosynthetic complex that spans the …

Loss Of Outer Membrane Porins In Clonally Related Clinical Isolates Of Klebsiella Pneumoniae Modifies The Bacteria; Resulting In Altered Resistance To Phagocytosis By Macrophages, Debra Nickole Brunson

UNF Graduate Theses and Dissertations

Klebsiella pneumoniae is an opportunistic pathogen responsible for lobar pneumoniae, liver abscess, and septicemia. Clinical isolates are found to be extended spectrum beta lactamase positive with differential expression of the two classical porins, OmpK35 and OmpK36. Porin loss is associated with increased minimum inhibitory concentrations of beta lactam, cephalosporin, and carbapenem antibiotics that target the peptidoglycan. However, little is known about how porin loss affects other aspects of the cell envelope. The focus of this study was to characterize clinical isolates exhibiting differential porin expression and determine if the cumulative changes altered the resistance to phagocytosis by macrophages. The results …

Mycobacterium Species Identification In An Acute Hospital: Towards Rapid Identification, And Improved Epidemiology, Using Novel Mass Spectrometry Analysis, James Anthony O'Connor

Theses

Mycobacteria are a heterogeneous group of bacteria that cause a wide spectrum of disease, including Tuberculosis (TB), the single biggest killer worldwide. The genus also incorporates over 170 nontuberculosis (NTM) species, many of which are opportunistic pathogens. The aim of this project was to ascertain the burden of mycobacterial disease in the region and to determine the efficacy of Matrix-Assisted Laser Desorption/Ionisation time-of-flight (MALDI-tof) mass spectrometry (MS) for novel uses as a rapid identification method for clinical mycobacteria and as a typing tool for Mycobacterium tuberculosis complex isolates. A five-year retrospective epidemiological study of the region was conducted, the first …

Metabolic Characteristics Of Macrophage Activation With Phenotype Microarrays, Tanya Kathryn D'Souza

Theses

Inflammation is a natural protective response and is characterised by the activation of numerous immune cells, including macrophages which can release a variety of inflammatory mediators. Macrophages play a flexible role in the initiation and effector phases of the immune response and change their behaviour to respond to environmental stimuli. The main objectives in this study were to create and characterise different macrophage behaviours and employ a novel metabolic characterisation platform the Phenotype Microarray^TM to attribute additional characteristics to the currently well recognised phenotypes. Five activated macrophage states were demonstrated and characterised. Unactivated macrophages (MO) demonstrated undetectable levels of …

Measuring Bacterial Growth Using A 3d-Printable Spectrometer, Samuel R. Bunting

Williams Honors College, Honors Research Projects

Visible light spectroscopy is a commonly used technique for measuring the growth of bacterial cultures, and growth curves provide broadly important data. However, the equipment and resources required for these experiments has been restricted to higher education and industry due to high cost and sophistication. We have previously reported on an inexpensive, 3D-printable photospectrometer called the SpecPhone. This device utilizes an iPhone as the camera, along with several other, inexpensive additions to make a fully functional spectrometer. Here, the application of the SpecPhone is expanded to the quantification of actively dividing E. coli cultures. Two protocols have been developed; one …

Molecular Biology Of A Surface-Exposed Protein Family Of Bartonella Bacilliformis, Hannah Fay

Undergraduate Theses, Professional Papers, and Capstone Artifacts

Bartonella bacilliformis is a gram negative alpha-proteobacterium native to the Andes of South America. Bartonella causes Carrion’s disease, a potentially life threatening disease transmitted by the sand fly. It has a mortality rate of 88% when untreated and 10% when treated. Diagnostics and control measures for the disease are underdeveloped and no vaccine is available. Recent outbreaks indicate that the range of the pathogen is increasing with nearly 1.7 million people in western South America at risk. Little is known about the epidemiology and pathogenesis of B. bacilliformis. Recent research done by UC San Diego found a paralogous gene …

Contribution Of A Class Ii Ribonucleotide Reductase To The Manganese Dependence Of Streptococcus Sanguinis, John L. Smith

Theses and Dissertations

Manganese-deficient Streptococcus sanguinis mutants exhibit a dramatic decrease in virulence for infective endocarditis and in aerobic growth in manganese-limited media. Loss of activity of a manganese-dependent, oxygen-dependent ribonucleotide reductase (RNR) could explain the decrease in virulence. When the genes encoding this RNR are deleted, there is no growth of the mutant in aerobic broth culture or in an animal model. Testing the contribution of the aerobic RNR to the phenotype of a manganese transporter mutant, a heterologous class II RNR from Lactobacillus leichmannii called NrdJ that requires B₁₂ rather than manganese as a cofactor was previously introduced into an …

What's In A Name? New Bacterial Species And Changes To Taxonomic Status From 2012 Through 2015, Erik Munson, Karen C. Carroll

Clinical Lab Sciences Faculty Research and Publications

Technological advancements in fields such as molecular genetics and the human microbiome have resulted in an unprecedented recognition of new bacterial genus/species designations by the International Journal of Systematic and Evolutionary Microbiology. Knowledge of designations involving clinically significant bacterial species would benefit clinical microbiologists in the context of emerging pathogens, performance of accurate organism identification, and antimicrobial susceptibility testing. In anticipation of subsequent taxonomic changes being compiled by the Journal of Clinical Microbiology on a biannual basis, this compendium summarizes novel species and taxonomic revisions specific to bacteria derived from human clinical specimens from the calendar years 2012 through …

Using Extremophile Bacteriophage Discovery In A Stem Education Professional Development Partnership To Explore Model Classroom Research Experiences Integrating The Three Dimentions Of The Next Generation Science Standards, Carrie L. Boudreau Ms

All Student Scholarship

The National Research Council’s (NRC) A Framework for K-12 Science Education: Practices, Crosscutting Concepts, and Core Ideas describes a vision of what it means to be proficient in science. The project discussed in this thesis was developed with a NIH SEPA Grant 8R25OD010937 to the Virology and Electron Microscopy Laboratory at the University of Southern Maine (USM) under the direction of Dr. S. Monroe Duboise. The goal of the project was to explore using discovery of extreme environment bacteria and their bacteriophages as a model for using the three dimensions of learning to teach Next Generation Science Standards (NGSS). Specifically, …

Characterization Of A Putative Hemolysin Expressed By Sneathia Amnii, A Preterm Birth-Associated Pathogen, Lizette Carrasco, Kimberly Jefferson

Undergraduate Research Posters

The gram-negative bacteria Sneathia amnii is a poorly-characterized commensal of the female urogenital tract frequently associated with adverse clinical outcomes such as bacterial vaginosis (BV), amnionitis, and preterm labor. To investigate its potential role in virulence, we sought to identify and characterize virulence determinants produced by S. amnii in an effort to better understand the pathogenesis of infectious preterm birth. Through sequencing of the Sn35 genome (type strain of S. amnii), we identified two genes with amino acid sequence similarity and structural similarity to the filamentous hemagglutinin (FHA) protein of Bordetella pertussis and its Type Vb transporter. Because S. amnii …

Comparative Genomic Analysis Of Two Serotype 1/2b Listeria Monocytogenes Isolates From Analogous Environmental Niches Demonstrates The Influence Of Hypervariable Hotspots In Defining Pathogenesis, Aidan Casey, Kieran Jordan, Aidan Coffey, Edward M. Fox, Olivia Mcauliffe

Department of Biological Sciences Publications

The vast majority of clinical human listeriosis cases are caused by serotype 1/2a, 1/2b, 1/2c, and 4b isolates of Listeria monocytogenes. The ability of L. monocytogenes to establish a systemic listeriosis infection within a host organism relies on a combination of genes that are involved in cell recognition, internalization, evasion of host defenses, and in vitro survival and growth. Recently, whole genome sequencing and comparative genomic analysis have proven to be powerful tools for the identification of these virulence-associated genes in L. monocytogenes. In this study, two serotype 1/2b strains of L. monocytogenes with analogous isolation sources, but …

The Vibrio Cholerae Minor Pilin Tcpb Initiates Assembly And Retraction Of The Toxin-Coregulated Pilus, Dixon Ng, Tony Harn, Tuba Altindal, Subramania Kolappan, Jarrad Marles, Rajan Lala, Ingrid Spielman, Yang Gao, Caitlyn Hauke, Gabriela Kovacikova

Dartmouth Scholarship

Type IV pilus (T4P) systems are complex molecular machines that polymerize major pilin proteins into thin filaments displayed on bacterial surfaces. Pilus functions require rapid extension and depolymerization of the pilus, powered by the assembly and retraction ATPases, respectively. A set of low abundance minor pilins influences pilus dynamics by unknown mechanisms. The Vibrio cholerae toxin-coregulated pilus (TCP) is among the simplest of the T4P systems, having a single minor pilin TcpB and lacking a retraction ATPase. Here we show that TcpB, like its homolog CofB, initiates pilus assembly. TcpB co-localizes with the pili but at extremely low levels, equivalent …

Amino Acid Catabolism In Staphylococcus Aureus, Cortney Halsey

Theses & Dissertations

Staphylococcus aureus must rapidly adapt to a variety of carbon and nitrogen sources during invasion of a host. Within a staphylococcal abscess, preferred carbon sources such as glucose are limiting, suggesting S. aureus survives through the catabolism of secondary carbon sources. S. aureus encodes pathways to catabolize multiple amino acids including those that generate pyruvate, 2-oxoglutarate, and oxaloacetate. To assess amino acid catabolism, S. aureus JE2 and mutants were grown in complete defined medium containing 18 amino acids but lacking glucose (CDM). A mutation in glutamate dehydrogenase (gudB), which generates 2-oxoglutarate from glutamate, abrogated growth in CDM suggesting …

Xpert Mtb/Rif Assay Shows Faster Clearance Of Mycobacterium Tuberculosis Dna With Higher Levels Of Rifapentine Exposure., A Jayakumar, R M Savic, C K Everett, Debra Benator, D Alland, C M Heilig, M Weiner, S O Friedrich, N A Martinson, A Kerrigan, C Zamudio, S V Goldberg, W C Whitworth, J L Davis, P Nahid

Medicine Faculty Publications

The Xpert MTB/RIF assay is both sensitive and specific as a diagnostic test. Xpert also reports quantitative output in cycle threshold (CT) values, which may provide a dynamic measure of sputum bacillary burden when used longitudinally. We evaluated the relationship between Xpert CT trajectory and drug exposure during tuberculosis (TB) treatment to assess the potential utility of Xpert CT for treatment monitoring. We obtained serial sputum samples from patients with smear-positive pulmonary TB who were consecutively enrolled at 10 international clinical trial sites participating in study 29X, a CDC-sponsored Tuberculosis Trials Consortium study evaluating the tolerability, safety, and antimicrobial activity …

The Role Of Streptococcus Gallolyticus Subspecies Gallolyticus In Colon Cancer Development, Jennifer L. Herold

Dissertations and Theses (Open Access)

Colorectal cancer (CRC) is the third most common cancer in men and women and is also the third most common cause of cancer death. A large body of evidence points towards the possibility that bacteria can have a significant impact on the development of cancer. It has been suggested that Streptococcus gallolyticus subsp. gallolyticus, a group D streptococci, may play a role in the development of CRC. Sg, formerly S. bovis biotype I, has been shown to be highly associated with CRC. In observing patients with either Sg bacteremia or endocarditis it was found that 25-80% of …