Microbiology Commons^™

Targeting The Pin Domain Of Type Ii Toxins Is A Novel Approach To Treat Infections Caused By Nontypeable Haemophilus Influenzae, Ashley Lynne Molinaro

Biomedical Sciences Theses & Dissertations

Toxin-antitoxin (TA) gene pairs have been identified in nearly all bacterial genomes sequenced to date and are thought to facilitate persistence and antibiotic tolerance. TA loci are classified into various types based upon the characteristics of their antitoxins, with those in type II expressing proteic antitoxins. Many toxins from type II modules are ribonucleases that maintain a PilT N-terminus (PIN) domain containing conserved amino acids considered essential for activity. The vapBC (virulence associated protein) TA system is the largest subfamily in this class and has been linked to pathogenesis of nontypeable Haemophilus influenzae (NTHi). This dissertation presents three studies investigating …

Heterotrophic Protists As Useful Models For Studying Microbial Food Webs In A Model Soil Ecosystem And The Universality Of Complex Unicellular Life, Andrew Robert Thompson

Theses and Dissertations

Heterotrophic protists, consisting largely of the Cercozoa, Amoebozoa, Ciliophora, Discoba and some Stramenopiles, are a poorly characterized component of life on Earth. They play an important ecological role in soil communities and provide key insights into the nature of one of life’s most enigmatic evolutionary transitions: the development of the complex unicell. Soil ecosystems are crucial to the functioning of global biogeochemical cycles (e.g. carbon and nitrogen) but are at risk of drastic change from anthropogenic climate change. Heterotrophic protists are the primary regulators of bacterial diversity in soils and as such play integral roles in biogeochemical cycling, nutrient mobilization, …

Bottom-Up Controls (Micronutrients And N And P Species) Better Predict Cyanobacterial Abundances In Harmful Algal Blooms Than Top-Down Controls (Grazers), Scott Andrew Collins

Theses and Dissertations

The initiation, bloom, and bust of harmful Cyanobacteria and algae blooms (HAB) in lakes are controlled by top-down and bottom-up ecological controls. Excess phosphorous and nitrogen inputs from anthropogenic sources are primary to blame, but eukaryotic grazers may also promote or curb Cyanobacteria dominance. We tracked shifts in bacterial composition, lake chemistry, and eukaryotic grazing community weekly or bi-weekly through spring and summer and modeled the causes of specific Cyanobacterial species blooms and busts across three lakes in Utah, USA, with differing lake trophic states. Regardless of trophic status, all three lakes experienced blooms of varying composition and duration. Aphanizomenon …

Role Of Gp120 Glycosylation In Sexual Transmission Of Hiv, Yingxue Sun, Adam Meadows, Najwa Zebian, Eric Arts, Carole Creuzenet

Western Research Forum

Background:

In chronic HIV patients, the viral populations are genetically diverse due to mutations introduced by the viral reverse transcriptase during HIV replication. However, more than 80% new infections result from single transmission founder (TF) viruses; therefore, targeting the TFs is key to control AIDS worldwide.

Gp120 is a glycosylated envelope protein required for HIV infection, propagation, and transmission. Glycans on gp120 influence HIV infectivity through their interactions with lectins, the carbohydrate-binding immune proteins in the host mucosa. To transmit sexually, viruses must overcome the lectin traps to access more target T cells.

Hypothesis:

TF viruses are less likely to …

Molecular Detection Of Pathogenic Leptospira Throughout The Caribbean, Zamara R. Garcia Truitt

Biology Theses

Leptospirosis is a common widespread zoonotic disease found throughout the Caribbean. The infection is produced by a pathogenic Leptospira species found in tropical and subtropical regions. The severity of the disease ranges from a mild asymptomatic infection to death. Leptospirosis is a neglected tropical disease due to the lack of public awareness and health approaches. Therefore, misdiagnosis is common because the symptoms are similar to that of other tropical endemic diseases. The aim of the study was to determine the presence of pathogenic Leptospira in water samples collected from Puerto Rico and Trinidad. Sixty-four environmental water samples were collected throughout …

Iron-Sulfur Cluster Biosynthesis In Methanogens, Cuiping Zhao

LSU Doctoral Dissertations

Methanogens live in a syntrophic consortium with bacteria, taking advantage of the metabolic abilities of their syntrophic partners to overcome energetic barriers and break down compounds that they cannot digest by themselves. Interspecies electron transfer, which is a major type of microbial communication in syntrophic processes, improves methanogenesis and anaerobic oxidization of methane (AOM) processes involved in syntrophic consortia. These processes have a significant impact on the global carbon cycle. Most of the essential enzymes involved in methanogenesis are iron-sulfur proteins. Iron-sulfur clusters are one of the oldest and most versatile cofactors present in all domains of life. To date, …

Cross-Species Genome-Wide Analysis Reveals Molecular And Functional Diversity Of The Unconventional Interferon-Ω Subtype, Lauren E. Shields, Jordan Jennings, Qinfang Liu, Jinhwa Lee, Wenjun Ma, Frank Blecha, Laura C. Miller, Yongming Sang

Agricultural and Environmental Sciences Faculty Research

Innate immune interferons (IFNs), particularly type I IFNs, are primary mediators regulating animal antiviral, antitumor, and cell-proliferative activity. These antiviral cytokines have evolved remarkable molecular and functional diversity to confront ever-evolving viral threats and physiological regulation. We have annotated IFN gene families across 110 animal genomes, and showed that IFN genes, after originating in jawed fishes, had several significant evolutionary surges in vertebrate species of amphibians, bats and ungulates, particularly pigs and cattle. For example, pigs have the largest but still expanding type I IFN family consisting of nearly 60 IFN-coding genes that encode seven IFN subtypes including multigene subtypes …

Msphere Of Influence: The View From The Microbiologists Of The Future, Aaron Mitchell, Ira Blader, Patricia Bradford, Sarah E. F. D'Orazio, W. Paul Duprex, Craig D. Ellermeier, Ana Fernandez-Sesma, Michael J. Imperiale, Katherine Mcmahon, Marcela F. Pasetti, Susannah Tringe

Microbiology, Immunology, and Molecular Genetics Faculty Publications

No abstract provided.

Substrate Utilization Of The Emerging Fungal Pathogen, Candida Auris, And The Antifungal Activity Of Select Essential Oils, Ryan Parker

Master of Science in Integrative Biology Theses

Candida auris is an emerging fungal pathogen that commonly causes nosocomial blood infections in the immunocompromised. Three factors make this emerging pathogen a global threat. First, it is frequently misidentified by commonly used diagnostic platforms. Second, it is able to survive for weeks on fomites. Third, it is almost always drug resistant, sometimes to all three classes of antifungal drugs used to treat Candida infections. The objectives of this study are three-fold. First, two existing methods, population estimation using absorbance-based standard curves and methylene blue viability staining, were investigated as to application in determining Candida auris cell population size and …

Porcine Interferon Complex And Co-Evolution With Increasing Viral Pressure After Domestication, Jordan Jennings, Yongming Sang

Agricultural and Environmental Sciences Faculty Research

Consisting of nearly 60 functional genes, porcine interferon (IFN)-complex represents an evolutionary surge of IFN evolution in domestic ungulate species. To compare with humans and mice, each of these species contains about 20 IFN functional genes, which are better characterized using the conventional IFN-α/β subtypes as examples. Porcine IFN-complex thus represents an optimal model for studying IFN evolution that resulted from increasing viral pressure during domestication and industrialization. We hypothesize and justify that porcine IFN-complex may extend its functionality in antiviral and immunomodulatory activity due to its superior molecular diversity. Furthermore, these unconventional IFNs could even confer some functional and …

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 …

Equivalency Of Indirect And Direct Potable Reuse Paradigms Based On A Quantitative Microbial Risk Assessment Framework, Erfaneh Amoueyan, Yongsheng He, Hongjie Wu, Chuanwei Zhu, Shichun Huang, Jian Huang

Civil and Environmental Engineering and Construction Faculty Research

Due to rapid growth in the potable reuse industry, there is a need to better characterize the associated pathogen risks and degree of attenuation achieved by various treatment trains. It is also important to understand how emerging treatment frameworks compare to the historical practice of de facto reuse. As such, the goals of this study were to (1) evaluate the equivalency of indirect potable reuse (IPR) and direct potable reuse (DPR) systems; (2) compare alternative treatment trains; and (3) identify the design components and operational conditions that are most critical to minimizing public health risks. To this end, we developed …

Antimicrobial Susceptibility Against Metronidazole And Carbapenem In Clinical Anaerobic Isolates From Pakistan, Kauser Jabeen, Yusra Shafquat, Joveria Farooqi, Kiran Mehmood, Seema Irfan, Rumina Hasan, Afia Zafar

Department of Pathology and Laboratory Medicine

Background: Globally metronidazole and carbapenem resistance in anaerobic organisms is increasing necessitating continuous surveillance to guide selection of empirical treatment. In this study we have determined metronidazole resistance in anaerobes using MIC Evaluator strips (M.I.C.E strips). Carbapenem resistance was evaluated only in metronidazole resistant isolates.
Material and methods: The study was conducted at the Aga Khan University (AKU) Hospital laboratory, Karachi, Pakistan (2014–2017). Metronidazole and imipenem resistance was evaluated using M.I.C.E strips and minimum inhibitory concentrations (MICs) were interpreted using Clinical Laboratory Standards Institute (CLSI) criteria. Clinical details including demographics, prolonged hospital stay, malignancy, transplant, dialysis, diabetes, site of infection …

The Gene Encoding Nad-Dependent Epimerase/Dehydratase, Wcag, Affects Cell Surface Properties, Virulence, And Extracellular Enzyme Production In The Soft Rot Phytopathogen, Pectobacterium Carotovorum, Rabiul Islam, Shyretha Brown, Ali Taheri, C. Korsi Dumenyo

Agricultural and Environmental Sciences Faculty Research

Pectobacterium carotovorum is a gram-negative bacterium that, together with other soft rot Enterobacteriaceae causes soft rot disease in vegetables, fruits, and ornamental plants through the action of exoproteins including plant cell wall-degrading enzymes (PCWDEs). Although pathogenicity in these bacteria is complex, virulence levels are proportional to the levels of plant cell wall-degrading exoenzymes (PCWDEs) secreted. Two low enzyme-producing transposon Tn5 mutants were isolated, and compared to their parent KD100, the mutants were less virulent on celery petioles and carrot disks. The inactivated gene responsible for the reduced virulence phenotype in both mutants was identified as wcaG. The gene, wcaG (previously …

Hawk On Wire: Ecopoems By Scott T. Starbuck, Vivian M. Hansen

The Goose

Review of Scott T. Starbuck’s Hawk on Wire: Ecopoems

Biomethane Production From Distillery Wastewater, Zachary Christman

Department of Agronomy and Horticulture: Dissertations, Theses, and Student Research

Distillery wastewater treatment is a great ecological problem, for example, India produces 2.7 billion liters of alcohol that results in 40 billion liters of wastewater. However, this material can be seen as a resource since 11 million cubic meters of biogas at 60% methane could be produced in addition to cleaning the water. The distillery has two options of what to do with the biogas. The first is to use the biogas to fuel the distillery making the production plant more energy efficient and removing some of the need to buy natural gas. The other is to upgrade the biogas …

Culture-Based Analysis Of ‘Cave Silver’ Biofilms On Rocks In The Former Homestake Mine In South Dakota, Usa, Amanpreet K. Brar, David Bergmann

International Journal of Speleology

Tunnels in a warm, humid area of the 1478 m level of the Sanford Underground Research Facility (SURF), located in a former gold mine in South Dakota, USA, host irregular, thin whitish, iridescent biofilms, which appear superficially similar to ‘cave silver’ biofilms described from limestone and lava tube caves, despite the higher rock temperature (32°C) and differing rock surface (phyllite) present at SURF. In this study, we investigated the diversity of cultivable bacteria constituting the cave silver by using several media: CN agar, CN gellan gum and 0.1X R2A agar. The highest colony count (CFU/g of sample) was observed on …

The Anti-Sigma Factor Muca Of Pseudomonas Aeruginosa: Dramatic Differences Of A Muca22 Vs. A Δmuca Mutant In Anaerobic Acidified Nitrite Sensitivity Of Planktonic And Biofilm Bacteria In Vitro And During Chronic Murine Lung Infection, Warunya Panmanee, Shengchang Su, Michael J. Schurr, Gee W. Lau, Xiaoting Zhu, Zhaowei Ren, Cameron T. Mcdaniel, Long J. Lu, Dennis E. Ohman, Daniel A. Muruve, Ralph J. Panos, Hongwei D. Yu, Thomas B. Thompson, Boo Shan Tseng, Daniel J. Hassett

Life Sciences Faculty Research

Mucoid mucA22 Pseudomonas aeruginosa (PA) is an opportunistic lung pathogen of cystic fibrosis (CF) and chronic obstructive pulmonary disease (COPD) patients that is highly sensitive to acidified nitrite (A-NO2-). In this study, we first screened PA mutant strains for sensitivity or resistance to 20 mM A-NO2- under anaerobic conditions that represent the chronic stages of the aforementioned diseases. Mutants found to be sensitive to A-NO2- included PA0964 (pmpR, PQS biosynthesis), PA4455 (probable ABC transporter permease), katA (major catalase, KatA) and rhlR (quorum sensing regulator). In contrast, mutants lacking PA0450 (a putative phosphate transporter) and PA1505 (moaA2) were A-NO2- resistant. However, …

The Effect Of Intracellular Zinc Levels In Escherichia Coli On Metallo-Β-Lactamase Activity, Jill Thompson

Graduate School of Biomedical Sciences Theses and Dissertations

Antibiotic resistance is a consequence of evolution via natural selection and poses a serious threat to the world's population. Escherichia coli, and other bacterial species, have acquired genes encoding Metallo-β-Lactamases (MBLs). MBLs are zinc-dependent enzymes that degrade most β-lactam antibiotics, and have emerged as important antibacterial resistance determinants in multidrug resistant pathogens. There are several different families of MBLs, and the major clinically relevant ones are Verona Integrated-encoded Metallo-β-Lactamases (VIMs), Imipenemases (IMPs), and New Delhi Metallo-β-Lactamases (NDMs). These enzymes confer high level resistance to penicillins, cephalosporins, and carbapenems, and are not inhibited by FDA-approved β-lactamase inhibitors. Variants of NDM have …

Anti-Human Cd9 Antibody Fab Fragment Impairs The Internalization Of Extracellular Vesicles And The Nuclear Transfer Of Their Cargo Proteins., Mark F. Santos, Germana Rappa, Jana Karbanová, Cheryl Vanier, Chikao Morimoto, Denis Corbeil, Aurelio Lorico

College of Osteopathic Medicine (TUN) Publications and Research

The intercellular communication mediated by extracellular vesicles (EVs) has gained international interest during the last decade. Interfering with the mechanisms regulating this cellular process might find application particularly in oncology where cancer cell-derived EVs play a role in tumour microenvironment transformation. Although several mechanisms were ascribed to explain the internalization of EVs, little is our knowledge about the fate of their cargos, which are crucial to mediate their function. We recently demonstrated a new intracellular pathway in which a fraction of endocytosed EV-associated proteins is transported into the nucleoplasm of the host cell via a subpopulation of late endosomes penetrating …