Microbiology Commons^™

Beyond Bivariate Correlations: Three-Block Partial Least Squares Illustrated With Vegetation, Soil, And Topography, Daehyun Kim, Thomas J. Dewitt, César S. B. Costa, John A. Kupfer, Ryan W. Mcewan, J. Anthony Stallins

Biology Faculty Publications

Ecologists, particularly those engaged in biogeomorphic studies, often seek to connect data from three or more domains. Using three-block partial least squares regression, we present a procedure to quantify and define bi-variance and tri-variance of data blocks related to plant communities, their soil parameters, and topography. Bi-variance indicates the total amount of covariation between these three domains taken in pairs, whereas tri-variance refers to the common variance shared by all domains. We characterized relationships among three domains (plant communities, soil properties, topography) for a salt marsh, four coastal dunes, and two temperate forests spanning several regions in the world. We …

Community-Acquired Methicillin-Resistant Staphylococcus Aureus (Ca-Mrsa) Usa300 Perturbs Acquisition Of Lysosomal Hydrolases And Requires Phagosomal Acidification For Survival In A Human Macrophage Cell Line, Zachary Ronald Tranchemontagne

All Theses And Dissertations

Community-acquired Methicillin-resistant Staphylococcus aureus (CA-MRSA) strain USA300 is a major cause of invasive drug-resistant skin and soft tissue infections in humans. Although S. aureus is a well-recognized extracellular pathogen, recent reports that USA300 survives inside host macrophages suggest that the intramacrophage environment may be a niche for persistent infection. Intramacrophage survival requires bacteria to avoid destruction in the phagosome; however, mechanisms by which USA300 evades phagosomal defenses are unclear. We examined the fate of the USA300-containing phagosome in human THP-1 macrophages by evaluating phagosomal acidification and maturation, and by testing the impact of phagosomal conditions on bacterial viability. Utilizing confocal …

Cultivation-Dependent Analysis Of Microorganisms Associated With Various Hydraulic Fracturing Fluids, Anthony Harrington

UNLV Theses, Dissertations, Professional Papers, and Capstones

The overarching goal of this study is to gain more insight to the microbial interactions associated with hydraulic fracturing by studying the culturable microorganisms present in various types of hydraulic fracturing fluids. Extraction of natural gas and other unconventional resources using hydraulic fracturing has increased in the last decade and very few studies have been conducted on the microorganisms associated with the various water types used in the process. From the very few published studies, the only cultivation-dependent method used involved determining the most probable number (MPN) of various metabolic groups, however the researchers failed to ask more in-depth questions …

The Effects Of Honeybee (Apis Mellifera) Antimicrobial Peptides On Paenibacillus Larvae, Jasmin Camille Khilnani

UNLV Theses, Dissertations, Professional Papers, and Capstones

American Foulbrood Disease (AFB) is the most detrimental bacterial disease that affects honeybee larvae (Apis mellifera) worldwide. The etiological agent of AFB is the Gram-positive, spore-forming bacterial pathogen, Paenibacillus larvae. Treatment with antibiotics, specifically oxytetracycline, has led to the development of antibiotic resistance in P. larvae. Therefore, there is a pressing need for an alternative treatment method. The overall goal of this project was to test naturally occurring, active antimicrobial peptides (AMPs), which are produced in the adult honeybee, against vegetative P. larvae. These active AMPs could potentially be used as a prophylactic treatment to prevent P. larvae infection of …

Coxiella Burnetii And Leishmania Mexicana Residing Within Similar Parasitophorous Vacuoles Elicit Disparate Host Responses, Jess A. Millar, Raquel Valdés, Fenil Kacharia, Scott M. Landfear, Eric D. Cambronne, Rahul Raghavan, Lynn Soong, Emilio Luis Malchiodi

Biology Faculty Publications and Presentations

Coxiella burnetii is a bacterium that thrives in an acidic parasitophorous vacuole (PV) derived from lysosomes. Leishmania mexicana, a eukaryote, has also independently evolved to live in a morphologically similar PV. As Coxiella and Leishmania are highly divergent organisms that cause different diseases, we reasoned that their respective infections would likely elicit distinct host responses despite producing phenotypically similar parasite-containing vacuoles. The objective of this study was to investigate, at the molecular level, the macrophage response to each pathogen. Infection of THP-1 (human monocyte/macrophage) cells with Coxiella and Leishmania elicited disparate host responses. At 5 days post-infection, when …

Regulation Of Vancomycin Resistance And Stress Response By The Msaabcr Operon In Staphylococcus Aureus, Dhritiman Samanta

Dissertations

Staphylococcus aureus is the predominant cause of public health problems around the world. Vancomycin has been an important antibiotic against Methicillin Resistant Staphylococcus aureus (MRSA) infections. However, Vancomycin Intermediate S. aureus (VISA) strains have been reported. These strains are characterized by thick cell walls, reduced autolytic rate, reduced PBP4 activity, and increased amount of D-Ala-D-Ala termini in the cell wall. In this study, we show that the msaABCR operon regulates vancomycin resistance in two clinical VISA strains. Deletion of the msaABCR operon in strains Mu50 and HIP6297 resulted in a significant decrease in the minimum inhibitory concentration (MIC) for vancomycin. …

Gene Regulation By A Novel Two-Component System Conserved Among Gammaproteobacteria, Kristin M. Jacob

All NMU Master's Theses

Two-component systems are common gene regulatory pathways seen in bacteria. Gene expression is controlled by these systems through a series of phosphorylation events between two proteins, a membrane bound sensor kinase and a cytoplasmic response regulator. Activation of a two-component system can be caused by biological or environmental stimuli, resulting in altered gene expression. A conserved two-component system was recently discovered in entomopathogenic bacteria, including our model organisms Pseudomonas entomophila and Pseudomonas aeruginosa, and is homologous to the recently identified two-component system, CrbRS, in Vibrio cholerae. In V. cholerae CrbRS regulates acetate metabolism and controls virulence. The aim of this …

Identification Of Genes Required To Synthesize An Antibiotic-Like Compound From The Soil Bacterium Rhodococcus Sp. Mtm3w5.2, Amber L. Ward

Electronic Theses and Dissertations

Rhodococcus is a soil bacterium, member of the Actinobacteria, and a close relative of the prolific small molecule producer Streptomyces. Recent interest in Rhodococcus as an under investigated source of possible bioactive secondary metabolites is sparked by the discovery of many polyketide synthase and non-ribosomal peptide synthetase genes of unknown function from sequenced Rhodococcus genomes. Rhodococcus species strain MTM3W5.2 was recently shown to produce a strong inhibitory compound with activity against most strains of Rhodococcus and closely related genera. A goal of this investigation is to discover the gene(s) required to synthesize this inhibitory molecule. The engineered Rhodococcus …

Algr Directly Controls Rsma In Pseudomonas Aeruginosa, Tyler Speaks

Electronic Theses and Dissertations

Pseudomonas aeruginosa is a bacterial pathogen that can infect any human tissue. The lungs of cystic fibrosis patients become chronically infected with Pseudomonas aeruginosa. Virulence factor gene expression is under elaborate regulatory control that remains poorly characterized. Understanding the regulatory hierarchy involved during infection is essential for identifying novel drug targets. RsmA is a post-transcriptional regulatory protein that controls expression of several virulence factors. Previous studies demonstrated alginate regulatory components AlgU and AlgR as regulators of rsmA expression. The aim of this study was to determine how AlgR controls rsmA expression. Western blot analysis of HA-tagged RsmA confirmed lower …

Kaposi’S Sarcoma-Associated Herpesvirus Transmission And Infection Among Young Zambian Children, Landon N. Olp

School of Biological Sciences: Dissertations, Theses, and Student Research

Kaposi’s sarcoma-associated herpesvirus (KSHV) is the etiologic agent for all forms of Kaposi’s sarcoma (KS)—one of the most common pediatric cancers in sub-Saharan Africa during the AIDS epidemic. KS was endemic in sub-Saharan Africa prior to the HIV/AIDS epidemic, but KS cases drastically increased thereafter. Our laboratory previously observed that KSHV infection is common among Zambian children and saliva is the major route of transmission. However, additional factors associated with the transmission of KSHV to children are poorly understood. Since a vaccine against KSHV is not currently available, it is paramount to understand factors associated with transmission so that alternative …

Symptomatic Surgically Treated Non-Neoplastic Cysts Of The Central Nervous System: A Clinicopathological Study From Pakistan, Nasir Ud Din, Huma Arshad, Zubair Ahmad, Sheema H Hasan, Mohammad Ehsan Bar

Department of Pathology and Laboratory Medicine

Objective: To report clinicopathologic features of symptomatic surgically removed non-neoplastic cysts of the central nervous system (CNS). Study Design: Case series. Place and Duration of Study: The Aga Khan University Hospital, Karachi, from 2003 to 2012. Methodology: All non-neoplastic CNS cysts reported during the study period were retrieved and reviewed. Age, gender, location, histologic type and clinical features were noted. Results: A total of 124 cysts were diagnosed in the study period. These included 44 epidermoid cysts (mean age 30.5 ± 13.8 years), 35 colloid cysts (mean age 31 ± 13.2 years), 32 arachnoid cysts (mean age 24.8 ± 20.2 …

Investigations Of Filarial Nematode Motility, Response To Drug Treatment, And Pathology, Charles Nutting

Dissertations

More than a billion people live at risk of chronic diseases caused by parasitic filarial nematodes. These diseases: lymphatic filariasis, onchocerciasis, and loaisis cause significant morbidity, degrading the health, quality of life, and economic productivity of those who suffer from them. Though treatable, there is no cure to rid those infected of adult parasites. The parasites can modulate the immune system and live for 10-15 years. Testing of compounds against filarial nematodes is complicated due to a lack of an objective platform on which to analyze in vitro treatments. There is no published, immunocompetent laboratory model for lymphatic filariasis. This …

N-Acetylglucosamine Regulates Virulence Properties In Microbial Pathogens, Shamoon Naseem, James B. Konopka

Department of Molecular Genetics and Microbiology Faculty Publications

There is growing evidence that the sugar N-acetylglucosamine (GlcNAc) plays diverse roles in cell signaling pathways that impact the virulence properties of microbes and host cells. GlcNAc is already well known as a ubiquitous structural component at the cell surface that forms part of bacterial cell wall peptidoglycan, cell wall chitin in fungi and parasites, and extracellular matrix glycosaminoglycans of animal cells. Chitin and peptidoglycan have been previously linked to cell signaling as they can stimulate responses in plant and animal host cells [1–3]. Recent studies now indicate that GlcNAc released from these polymers can also …

Simulation And Validation Of Radio Frequency Heating Of Shell Eggs, Soon Kiat Lau

Department of Food Science and Technology: Dissertations, Theses, and Student Research

Finite element models were developed with the purpose of finding an optimal radio frequency (RF) heating setup for pasteurizing shell eggs. Material properties of the yolk, albumen, and shell were measured and fitted into equations that were used as inputs for the model. When the egg was heated by itself, heating tend to be focused at the air cell to result in a “coagulation ring.” The focused heating near the air cell of the egg prevented satisfactory pasteurization of the egg, but deeper analysis of the simulation results offered a new perspective on how non-uniform RF heating could occur in …

Protective Properties Of Functionalised Tetrazine On An Aerospace Aluminium Alloy (Aa 2024-T3), Swarna Jaiswal, P.C. Rajath Varma, Brendan Duffy, Felicia Mutuma, Patrick Mchale

Articles

Environmental health concerns over conventional chromium based surface treatments on aluminium substrates are well known. Current research efforts have concentrated on developing protective technologies for multiple applications. Such properties would enable manufacturers to address both corrosion and bacterial threats in areas such as fuel tanks and delivery systems.

The present study explores the anticorrosion properties of 1,2-dihydro 1, 2, 4, 5 tetrazine-3, 6-dicarboxylic acid (H₂DCTZ) on a copper rich aerospace aluminium alloy (AA 2024-T3). Furthermore the antimicrobial activity of the tetrazine is evaluated against Gram-positive and Gram-negative bacteria, both capable of inducing corrosion. The protective action of the …

Selective Involvement Of The Checkpoint Regulator Vista In Suppression Of B-Cell, But Not T-Cell, Responsiveness By Monocytic Myeloid-Derived Suppressor Cells From Mice Infected With An Immunodeficiency-Causing Retrovirus, Kathy A. Green, Li Wang, Randolph J. Noelle, William R. Green

Dartmouth Scholarship

Inhibition of T-cell responses in tumor microenvironments by myeloid-derived suppressor cells (MDSCs) is widely accepted. We demonstrated augmentation of monocytic MDSCs whose suppression of not only T-cell, but also B-cell, responsiveness paralleled the immunodeficiency during LP-BM5 retrovirus infection. MDSCs inhibited T cells by inducible nitric oxide synthase (iNOS)/nitric oxide (NO), but uniquely, inhibition of B cells was ~50% dependent each on iNOS/NO and the MDSC-expressed negative-checkpoint regulator VISTA. Blockade with a combination of iNOS/NO and VISTA caused additive or synergistic abrogation of MDSC-mediated suppression of B-cell responsiveness.

Towards Bioregenerative Life Support For Extended Human Exploration: Experiment Development For Testing The Fitness Of Algae In Space, Audrey Fry, R. Craig Everroad, Jessica E. Koehne, Thomas E. Murphy, Brad M. Bebout

STAR Program Research Presentations

Microbes such as algae and bacteria are promising candidates for supporting extended human space travel, as they are robust sources of food, fuel, waste cycling, and oxygen production. Growing microbes on membranes reduces the mass and water demands of a bioreactor system, both of which are important considerations in space travel. The European Modular Cultivation System (EMCS) on the International Space Station (ISS) provides an ideal opportunity to test the effects of microgravity and other aspects of the space environment on algal growth on membranes. This project aims to find optimal growing conditions and measurement technologies that conform to the …

Isolation Of Possible Biocontrol Endophytic Bacteria From Solanum Tuberosum Effective Against Streptomyces Scabies., Annie Flatley, Luke Ogle, Adam Noel, Erica Fraley, Alaxandra Goodman, Donna Becker

Poster Sessions

Use of biological control offers a cost effective and environmentally safe method for controlling plant diseases. Biocontrol agents that can colonize roots and live endophytically within plant tissue should allow for effective disease control. The goal of this research was to develop protocols to isolate putative Streptomyces species from potato stem and tuber tissue due to their ability to produce inhibitory compounds which could potentially reduce diseases caused by Streptomyces scabies. Endophyte isolation from Solanum tuberosum (potato) plants (stem and tuber tissues) that were grown in a biocontrol field trial were the focus of this study. Several surface …

Use Of Two Pathogen-Inhibiting Streptomyces Isolates For Biocontrol Of Scab Disease Of Raphanus Sativus, Tyler Park, Nichole Klingler, Adam Noel, Luke Ogle, Annie Flatley, Donna Becker

Poster Sessions

Streptomyces species are ubiquitous soil bacteria that are promising as biological control agents due to their prolific antibiotic production that can inhibit soil-borne plant pathogens. This includes Streptomyces scabies, which causes scab disease on underground storage organs. The goal of this research was to test two Streptomyces isolates that have known inhibitory and biocontrol abilities against S. scabies in a potato (Solanum tuberosum) agricultural system for their effectiveness in biocontrol of this pathogen in a radish (Raphanus sativus) greenhouse assay. Pathogenic S. scabies were mixed into either pasteurized or unpasteurized soil prior to planting. Radish …

The Functional And Distributional Ecology Of Mycetozoans Under Changing Edaphic And Climatic Dynamics, Geoffrey Lloyd Zahn

Graduate Theses and Dissertations

Investigations into the distribution and ecosystem functions of fruiting amoebae revealed that local-scale environmental conditions can largely explain broad biogeographical patterns in species assemblage, the way in which amoeboid predators shape bacterial communities and how this top-down influence may affect global biogeochemical processes in a changing climate. The distribution and assemblage of protosteloid amoebae on the islands of New Zealand and Hawaii did not yield any expected patterns of island biogeography, and conformed to other global regions studied. The strongest predictor of species richness in a given region was sampling effort and these species do not appear to have any …

Inhibition Of Cell Differentiation In Bacillus Subtilis By Pseudomonas Protegens, Matthew J. Powers, Edgardo Sanabria-Valentín, Albert A. Bowers, Elizabeth A. Shanka

Publications and Research

Interspecies interactions have been described for numerous bacterial systems, leading to the identification of chemical compounds that impact bacterial physiology and differentiation for processes such as biofilm formation. Here, we identified soil microbes that inhibit biofilm formation and sporulation in the common soil bacterium Bacillus subtilis. We did so by creating a reporter strain that fluoresces when the transcription of a biofilm-specific gene is repressed. Using this reporter in a coculture screen, we identified Pseudomonas putida and Pseudomonas protegens as bacteria that secrete compounds that inhibit biofilm gene expression in B. subtilis. The active compound produced by P. protegens was …

Toll-Like Receptor 9-Mediated Inflammation Triggers Alveolar Bone Loss In Experimental Murine Periodontitis, Paul D. Kim, Xia Xia-Juan, Katie E. Crump, Toshiharu Abe, George Hajishengallis, Sinem E. Sahingur

Biology Faculty Articles

Chronic periodontitis is a local inflammatory disease induced by a dysbiotic microbiota and leading to destruction of the tooth-supporting structures. Microbial nucleic acids are abundantly present in the periodontium, derived through release after phagocytic uptake of microbes and/or from biofilm-associated extracellular DNA. Binding of microbial DNA to its cognate receptors, such as Toll-like receptor 9 (TLR9), can trigger inflammation. In this study, we utilized TLR9 knockout (TLR9^−/−) mice and wild-type (WT) controls in a murine model of Porphyromonas gingivalis-induced periodontitis and report the first in vivo evidence that TLR9 signaling mediates the induction of periodontal bone loss.P. gingivalis-infected …

Determining The Prevalence And Distribution Of Tick-Borne Pathogens In Southeastern Virginia And Exploring The Transmission Dynamics Of Rickettsia Parkeri In Amblyomma Maculatum, Chelsea L. Wright Thompson

Biological Sciences Theses & Dissertations

Tick-borne pathogens are an increasing threat to human and animal health worldwide. In the United States, cases of Lyme disease, spotted fever rickettsioses, ehrlichiosis and anaplasmosis are on the rise. Factors related to emergence include appearance of a new pathogen, recognition of an existing pathogen and environmental changes that result in new exposure events. Despite the rise in tick-borne disease incidence within many states, including Virginia, there is a paucity of data related to the prevalence and distribution of ticks and tick-borne pathogens.

The first aim of this dissertation research was to determine the tick-borne pathogen composition within tick populations …

Aspergillus Fumigatus Spinal Abscess In An Immunocompetent Child, Mohammad Faizan Zahid, Joveria Farooqi

Department of Pathology and Laboratory Medicine

No abstract provided.

Iron Chelation In Patients With Transfusion Dependent Thalassemia: An Insight On Response To Deferasirox, Muhammad Shariq Shaikh, Salman Naseem Adil

Department of Pathology and Laboratory Medicine

No abstract provided.

Deletion Of Nfnab In Thermoanaerobacterium Saccharolyticum And Its Effect On Metabolism, Jonathan Lo, Tianyong Zheng, Daniel G. Olson, Natalie Ruppertsberger, Shital Tripathi, Adam Guss, Lee Lynd

Dartmouth Scholarship

NfnAB catalyzes the reversible transfer of electrons from reduced ferredoxin and NADH to 2 NADP⁺. The NfnAB complex has been hypothesized to be the main enzyme for ferredoxin oxidization in strains of Thermoanaerobacterium saccharolyticum engineered for increased ethanol production. NfnAB complex activity was detectable in crude cell extracts of T. saccharolyticum. Activity was also detected using activity staining of native PAGE gels. The nfnAB gene was deleted in different strains of T. saccharolyticum to determine its effect on end product formation. In wild-type T. saccharolyticum, deletion of nfnAB resulted in a 46% increase in H₂ formation but …

Prokaryotic Diversity In The Rhizosphere Of Organic, Intensive, And Transitional Coffee Farms In Brazil, Adam Caldwell, Livia Silva, Cynthia Da Silva, Cleber Ouverney

Faculty Publications, Biological Sciences

Despite a continuous rise in consumption of coffee over the past 60 years and recent studies showing positive benefits linked to human health, intensive coffee farming practices have been associated with environmental damage, risks to human health, and reductions in biodiversity. In contrast, organic farming has become an increasingly popular alternative, with both environmental and health benefits. This study aimed to characterize and determine the differences in the prokaryotic soil microbiology of three Brazilian coffee farms: one practicing intensive farming, one practicing organic farming, and one undergoing a transition from intensive to organic practices. Soil samples were collected from 20 …

Genomic Signatures Of Cooperation And Conflict In The Social Amoeba, Elizabeth A. Ostrowski, Yufeng Shen, Xiangjun Tian, Richard Sucgang, Huaiyang Jiang, Jiaxin Qu, Mariko Katoh-Kurasawa, Debra A. Brock, Christopher Dinh, Fremiet Lara-Garduno, Sandra L. Lee, Christie L. Kovar, Huyen H. Dinh, Viktoriya Korchina, Laronda Jackson, Shobha Patil, Yi Han, Lesley Chaboub, Gad Shaulsky, Donna M. Muzny, Kim C. Worley, Richard A. Gibbs, Stephen Richards, Adam Kuspa, Joan E. Strassmann, David C. Queller

Biology Faculty Research

• Molecular evolution analyses reveal the history of social conflict
• Genes that mediate social conflict show signatures of frequency-dependent selection
• Balanced polymorphisms suggest that cheating may be stable and endemic

Cooperative systems are susceptible to invasion by selfish individuals that profit from receiving the social benefits but fail to contribute. These so-called "cheaters" can have a fitness advantage in the laboratory, but it is unclear whether cheating provides an important selective advantage in nature. We used a population genomic approach to examine the history of genes involved in cheating behaviors in the social amoeba Dictyostelium discoideum, testing whether these genes experience …

Vibrio Cholera: Detection And Destruction, Amber Brown, Dr. Julianne Grose

Journal of Undergraduate Research

Cholera, the Disease: Cholera is a disease that affects three to five million people each year with approximately 100,000 deaths. Transmitted mainly by the drinking-­‐water supply, it causes an infection in the small intestine leading to severe diarrhea and vomiting. If left untreated, it can cause death within hours. The disease is caused by the bacterium Vibrio cholerae which was first isolated by Filippo Pacini in 1854. Vibrio cholerae is gram negative, comma shaped, and flagellated. It is easily treated with modern water purification techniques, and as such it is most prevalent in developing countries that lack this infrastructure. Countries …

Biofilm Binding Capabilities Of Yersinia Pseudotuberculosis Mutants, Bailey Benson, Dr. David Erickson

Journal of Undergraduate Research

Yersinia pestis — the causative agent of the deadly bubonic plague, which killed over one-third of Europe in the 14th century – spreads quickly from person to person due to its ability to create a biofilm, characterized by bacterial adhesion to themselves and surfaces. The bacteria infects fleas and forms a biofilm in their midgut, which causes the flea to both feed more often and cough up bacteria biofim into each new host. In this way, the formation of a strong biofilm is essential for the rapid spread of the bubonic plague. In my experiment, I analyzed which genes would …