Microbiology Commons^™

Identification Of Blda As A Major Regulator Of Virulence In The Sweetpotato Soil Rot Pathogen Streptomyces Ipomoeae And Characterization Of Distinct Clostridium Sweetpotato Soft Rot Isolates, Kuei-Ting Yang

LSU Doctoral Dissertations

Streptomyces ipomoeae is the causative agent of Streptomyces soil rot on sweetpotato, a disease characterized by extensive necrosis of both adventitious and storage roots. While Streptomyces potato scab pathogens produce a phytotoxin (thaxtomin A), which is induced in the presence of cellobiose and suberin, S. ipomoeae produces a less-modified, phytotoxin (thaxtomin C), whose inducer has not been identified. To investigate transcriptional regulation of thaxtomin C production, we inserted a promoter involved in thaxtomin C synthesis upstream of the gusA reporter in an S. ipomoeae strain. Reporter gene expression was significantly upregulated in the presence of size-fractionated sweetpotato extract (SPE). The …

A Cophylogenetic Analysis Of Fungus Gardening Ants And Their Symbiotic Fungi, Katherine Beigel

Biology Theses

Fungus-growing ants (Tribe Attini) and their fungal cultivars share a 50-million-year coevolutionary history. Large scale phylogenetic analyses depict a strong co-phyletic signal among ants and their farmed fungi yet fungus sharing among unrelated ant lineages is somewhat widespread. An overview of sharing has been hampered by a lack of genetic markers that exhibit intraspecific variation and surveys across geographic regions. For example, previous studies have shown similar sequences of the internal transcribed spacer (ITS) region of fungus in different species of Trachymyrmex, suggesting that these ant species are farming the same fungal clone. To examine whether this was a …

Multistrain Hiv-1 Elimination: A Crispr-Cas9 And Theranostics-Based Approach, Jonathan Herskovitz

Theses & Dissertations

A critical barrier to achieving a functional cure for infection by human immunodeficiency virus type one (HIV-1) rests in the presence of latent proviral DNA integrated in the nuclei of host CD4+ T cells and mononuclear phagocytes. Accordingly, HIV-1-infected patients must adhere to lifelong regimens of antiretroviral therapy (ART) to prevent viral rebound, CD4+ T cell decline, and progression to acquired immunodeficiency syndrome (AIDS). Gene editing using clustered regularly interspersed short palindromic repeat (CRISPR)-Cas9 technology stands as one means to inactivate integrated proviral DNA. We devised a mosaic gRNA CRISPR-Cas9 system- TatDE- that targets viral transcriptional regulator genes tat / …

Applied Molecular Dynamics: From Targeting Viral Helicases, To Understanding The Interactions Of Cucurbituril Complexes In Ionic Solutions, Bryan Raubenolt

LSU New Orleans Theses and Dissertations

Molecular Dynamics simulations are a highly useful tool in helping understand the fundamental interactions present in a variety of chemical systems. The work discussed here illustrates it’s use in determining the conformational dynamics of the Zika and SARS-Cov-2 helicase in a physiological environment, largely in an effort to discover inhibitors capable of rendering the protein inert. Additionally, we show how it can be used to understand paradoxical trends in the anion-induced precipitation of Cucurbituril cavitands.

Viral helicases are motor proteins tasked with unwinding the viral dsRNA, a crucial step in preparing the strand to be translatable by host cells. By …

Inaction On Lead Despite The Relevant Knowledge: Predictors, Covariates, And Outreach Implications, Alessandra Rossi, Bernabas Wolde, Pankaj Lal, Melissa Harclerode

Department of Biology Faculty Scholarship and Creative Works

Testing residential soil and paint for lead provides actionable information. By showing where and how much lead exists on the residence, it allows one to quantify risk and determine the best ways to reduce exposure along with the corresponding health and financial costs. For these reasons, several federal and state programs offer outreach to audiences on the benefits of testing residential soil and paint for lead. Not all individuals who know about lead’s adverse health effects, however, test their residence for lead, potentially limiting the actionable information that could have helped to reduce their exposure. Such individuals represent a challenge …

Innate Pathogenic Traits In Oral Yeasts, Ayat Ibrahiem Esmaeel Al-Laaeiby, Adnan A. Al-Mousawi, Inaam M.N. Alrubayae, Abdullah Al-Saadoon, Maysoon Almayahi

Karbala International Journal of Modern Science

The normal flora community plays a significant role in both healthy and patient individual’s bodies. It has improved its ability to change from beneficial to opportunistic organisms causing crucial infections in immunocompromised patients. This study was conducted to identify the community of yeast species, and to investigate potential virulence factors. Saliva samples were collected from healthy individuals, yeast species were isolated and identified using both traditional and advance molecular genetics technique. The results revealed that Candida albicans was the dominant isolate, while Meyerozyma caribbica was the least. The phylogenetic tree was constructed for 13 species using the Neighbour-Joining method, which …

Microbial Dark Matter Coming To Light: Challenges And Opportunities, Jian Yu Jiao, Lan Liu, Zheng Shuang Hua, Bao Zhu Fang, En Min Zhou, Nimaichand Salam, Brian P. Hedlund, Wen Jun Li

Life Sciences Faculty Research

Microbes are the most abundant and diverse cellular life forms on Earth and colonize a wide range of environmental niches. However, more than 99% of bacterial and archaeal species have not been obtained in pure culture [1] and we have only glimpsed the surface of this mysterious microbial world. This is so-called Microbial Dark Matter (MDM): the enormous diversity of yet-uncultivated microbes that microbiologists can only study by using cultivation-independent techniques. Recently, a number of international projects have dramatically increased our understanding of the extent and distribution of microbial diversity, including the Global Catalogue of Microorganisms (GCM), the Genomic Encyclopedia …

Pandemic Vibrio Cholerae Shuts Down Site-Specific Recombination To Retain An Interbacterial Defence Mechanism, Francis J. Santoriello, Lina Michel, Daniel Unterweger, Stefan Pukatzki

Publications and Research

Vibrio cholerae is an aquatic microbe that can be divided into three subtypes: harmless environmental strains, localised pathogenic strains, and pandemic strains causing global cholera outbreaks. Each type has a contact-dependent type VI secretion system (T6SS) that kills neighbouring competitors by translocating unique toxic effector proteins. Pandemic isolates possess identical effectors, indicating that T6SS effectors may affect pandemicity. Here, we show that one of the T6SS gene clusters (Aux3) exists in two states: a mobile, prophage-like element in a small subset of environmental strains, and a truncated Aux3 unique to and conserved in pandemic isolates. Environmental Aux3 can be readily …

Impact Of Endangered Animal Protection Rights, Policies, And Practices On Zoonotic Disease Spread, Daniella Fedak-Lengel

Honors Projects

Building on field research in Costa Rica and Belize, this honors project analyzes environmental and endangered animal protection policies, rights, and practices in Central America and the Caribbean, and assesses the impact of veterinary science and biological research and practice, particularly conservation biology, on animal welfare concerns. Informed by the recent surge in awareness regarding zoonoses and zoonotic disease transmission, prevention and control, resulting from the current global pandemic of SARS-CoV-2, the project assesses the need for new and innovative types of collaboration, particularly involving conservation biologists, environmental scientists, public health experts, law and policy makers, and global trade and …

Climate Warming’S Alteration Of Host-Parasite Dynamics, Ting-Hsuan Wu

Binghamton University Undergraduate Journal

Parasites and pathogens have significant roles in host population control, and thus host-parasite interactions affect biodiversity. The important question reviewed in this paper is how changes in temperature due to climate change affect host-parasite interactions. There is mounting evidence that elevated temperatures have both beneficial and detrimental effects on parasites and independently on hosts. These independent changes result in altered host-parasite dynamics through various mechanisms. If elevated temperatures enhance parasite survival, risk of disease transmission among hosts is enhanced as well. This enhancement is dependent on temperature-induced shifts in the host lifecycle, as asynchrony in host and parasite development can …

The Role Of The Msaabcr Operon In Implant-Associated Chronic Osteomyelitis In Staphylococcus Aureus Usa300 Lac, Gyan S. Sahukhal, Michelle Tucci, Hamed Benghuzzi, Gerri Wilson, Mohamed O. Elasri

Faculty Publications

The msaABCR operon regulates several staphylococcal phenotypes such as biofilm formation, capsule production, protease production, pigmentation, antibiotic resistance, and persister cells formation. The msaABCR operon is required for maintaining the cell wall integrity via affecting peptidoglycan cross-linking. The msaABCR operon also plays a role in oxidative stress defense mechanism, which is required to facilitate persistent and recurrent staphylococcal infections. Staphylococcus aureus is the most frequent cause of chronic implant-associated osteomyelitis (OM). The CA-MRSA USA300 strains are predominant in the United States and cause severe infections, including bone and joint infections.

Study Of Plants Used Against Infections By California Native American Tribes, Maria J. Rojas

Master's Theses

The objectives of this research were to evaluate the antibacterial activity and to determine the chemical composition of a list of medicinal plants used by Native Americans in California. Artemisia californica, Mimulus aurantiacus, Equisetum telmateia, Equisetum hyemale, and Marah fabacea were selected from a list of plants reported as having been used for ailments related to infections by tribes located in California. The extracts obtained through steam distillation from E. telmateia, E. hyemale and M. fabacea were assayed for in vitro antibacterial activity against 16 Gram-negative and 6 Gram-positive bacteria using disk diffusion assays and measuring the diameters of inhibition …

Copper And Cobalt Metal Conjugation Enhances Flaviviral Replication, And Denv/Zikv Caused Thrombocytopenia Suppresses Integrin Signaling, Shovan Dutta

Biomedical Sciences Theses & Dissertations

Vector control is a global concern, and effective strategies have been on the way. Among the many different strategies, insect repellents to protect us from blood-feeding arthropods are very common. Food processing or preservatives in food expose us to several chemicals associated with insect repellents, insecticides, and pesticides. Using metallic conjugation with plant extracts or essential oils has become a widespread strategy to increase their efficacy. But it is worth it to be aware that some of those metallic compounds like Cobalt or Copper upon conjugation with thiosemicarbazone ligands derived from Citral and 2-acetylethiazole at the center coordination enhance both …

In The Margins: Reconsidering The Range And Contribution Of Diazotrophs In Nearshore Environments, Corday R. Selden

OES Theses and Dissertations

Dinitrogen (N₂) fixation enables primary production and, consequently, carbon dioxide drawdown in nitrogen (N) limited marine systems, exerting a powerful influence over the coupled carbon and N cycles. Our understanding of the environmental factors regulating its distribution and magnitude are largely based on the range and sensitivity of one genus, Trichodesmium. However, recent work suggests that the niche preferences of distinct diazotrophic (N₂ fixing) clades differ due to their metabolic and ecological diversity, hampering efforts to close the N budget and model N₂ fixation accurately. Here, I explore the range of N₂ fixation …

Drivers Of Rickettsial Pathogen Transmission And Spillover In Local Tick Populations In Southeastern Virginia, Alexandra Cumbie

Biomedical Sciences Theses & Dissertations

Cases of spotted fever group rickettsiosis are becoming more prevalent in the United States. In Virginia, there are three human-biting ticks which are largely responsible for the spread of rickettsial pathogens and the increase in disease cases. These species include Dermacentor variabilis, Amblyomma americanum, and Amblyomma maculatum; all of which are vectors of rickettsial agents to vertebrate hosts. These species are sympatric as adults and have the potential to share large and small mammal hosts. Their interactions on and off host and their associated rickettsiae were the focus of this dissertation work. Amblyomma americanum is the vector …

Ixodes Scapularis Src Kinase Is Required For Rickettsial Pathogen Survival In Ticks, Jeremy W. Turck

Biological Sciences Theses & Dissertations

Anaplasma phagocytophilum is an obligate intracellular bacterium that causes disease in humans and animals. It is the causative agent for human anaplasmosis. A. phagocytophilum uses certain strategies to infect both vertebrates and invertebrates. It uses Ixodes scapularis ticks as a vector for spreading infection to other mammal species. This bacterium has a specific path for infection through the salivary glands of its vector host. It also suppresses certain functions such as the inhibition of apoptosis and ROS production in order to increase its survival in ticks. Src kinase, a non-receptor protein-tyrosine kinase, is a major player in cell signaling. Src …

Two Hundred And Fifty-Four Metagenome-Assembled Bacterial Genomes From The Bank Vole Gut Microbiota, Anton Lavrinienko, Eugene Tukalenko, Timothy A. Mousseau, Luke R. Thompson, Rob Knight, Tapio Mappes, Phillip C. Watts

Faculty Publications

Vertebrate gut microbiota provide many essential services to their host. To better understand the diversity of such services provided by gut microbiota in wild rodents, we assembled metagenome shotgun sequence data from a small mammal, the bank vole Myodes glareolus (Rodentia, Cricetidae). We were able to identify 254 metagenome assembled genomes (MAGs) that were at least 50% (n = 133 MAGs), 80% (n = 77 MAGs) or 95% (n = 44 MAGs) complete. As typical for a rodent gut microbiota, these MAGs are dominated by taxa assigned to the phyla Bacteroidetes (n = 132 MAGs) and …

Investigation Of Sulfur Cycling In Marine Sponge Cinachyrella Spp. From A South Florida Reef, Shelby K. Cain

All HCAS Student Capstones, Theses, and Dissertations

Symbionts within marine sponges are actively participating in the biogeochemical cycles. Among them, the role of symbiont microbes in the sulfur cycle remains a mystery. This study measured the abundance of microbes within the genus Cinachyrella before and after exposure to hydrogen sulfide. A four-part study was conducted: a) five-hour drop experiments, b) vertical distribution experiments, c) five-hour uptake experiments, and d) long-term exposure experiments. The five-hour drop experiment utilized a microsensor to measure sulfide levels, which was lowered 1.0 mm every thirty minutes for a total of 5 hours. Three trials were performed, each with one sponge and a …

Comprehensive Survey Of The Litter Bacterial Communities In Commercial Turkey Farms, Bishnu Adhikari, Guillermo Tellez-Isaias, Tieshan Jiang, Brian Wooming, Young Min Kwon

Poultry Science Faculty Publications and Presentations

The importance of microbiota in the health and diseases of farm animals has been well-documented for diverse animal species. However, studies on microbiotas in turkey and turkey farms are relatively limited as compared to other farm animal species. In this study, we performed a comprehensive survey of the litter microbiotas in 5 commercial turkey farms in the Northwest Arkansas (H, M, V, K, and R farms) including one farm with positive incidence of cellulitis (R farm). Altogether 246 boot swabs were used for 16S rRNA gene profiling of bacterial communities. At phylum level, 11 major bacterial phyla (≥0.01%) were recovered. …

Incidence Of Antibiotic Resistance And Plasmid Content In Freshwater Beach Sand And Water And Clinical Urinary Tract Infection Escherichia Coli Isolates, Robert F. White

Biology Theses

Antibiotic-resistant (AR) bacteria have been found in environmental ecosystems including beach sand and water, and pose a serious threat to the mitigation of human and animal disease. The presence of antibiotic residues in the environment, fueled by wastewater effluent and agricultural runoff, may produce selective pressure on introduced microbes such as Escherichia coli, leading to the production of AR populations. This study characterized and compared the antibiotic resistance patterns and plasmid content of E. coli isolated from a freshwater beach and clinical urinary tract infection (UTI) samples. A higher level of antibiotic resistance was expected in clinical (UTI) Escherichia coli …

An Impedimetric Aptasensing System For The Rapid Detection Of Salmonella Typhimurium, America Sotero

Graduate Theses and Dissertations

Salmonella Typhimurium is a foodborne pathogen associated with raw and undercooked eggs, poultry, beef, fruits, and vegetables. In the United States, Salmonella is responsible for approximately 1.2 million illnesses, 23,000 hospitalizations, and 450 deaths annually. For many years, conventional detection methods such as culture-dependent and PCR-based methods have been the “golden standards” for the detection of this pathogen due to their high sensitivity and reliability. However, they still have some disadvantages such as long enrichment steps and high costs that need to be overcome. The development of a rapid and reliable method for the detection of S. Typhimurium is needed …

Microplastic Abundance, Distribution And Impacts On Sargassum-Associated Juvenile Fishes In The Gulf Of Mexico, Olivia Lestrade

Master's Theses

Microplastics are a concern in marine environments because they are highly durable, ubiquitous, and can be mistaken for food and ingested by small organisms. Pelagic Sargassum, an important habitat for larval and juvenile stages of many fish species, is found in large surface aggregations, and may provide complex structure in which microplastics become trapped. This could lead to greater risk of microplastic ingestion by fish early life stages associated with Sargassum habitats. To better understand the impacts of microplastics within Sargassum communities, this study examined 1) microplastic concentrations and ingestion by juvenile fishes associated with Sargassum; 2) the microbial …

Does The Presence Of Multiple Β-Lactamases In Gram-Negative Bacilli Impact The Results Of Antimicrobial Susceptibility Tests And Extended-Spectrum Β-Lactamase And Carbapenemase Confirmation Methods?, Fred C. Tenover, Caitlin M. Dela Cruz, Scott Dewell, Victoria M. Le, Isabella A. Tickler

Biology Faculty Publications

Objectives: Many multidrug-resistant Gram-negative bacilli (MDR-GNB) harbour multiple β-lactamases. The aim of this study was to assess the impact of multiple β-lactamase carriage on the accuracy of susceptibility tests and extended-spectrum β-lactamase (ESBL) and carbapenemase confirmation methods.

Methods: A total of 50 MDR-GNB, of which 29 carried multiple β-lactamases, underwent broth microdilution (BMD) and disk diffusion (DD) testing as well as confirmation tests for ESBLs and carbapenemases. Whole-genome sequencing (WGS) was used for β-lactamase gene identification.

Results: Categorical agreement of BMD and DD testing results ranged from 86.5 to 97.7% for 10 β-lactam agents. BMD and DD algorithms for ESBL …

Role Of Β-Glucan Structure In Dectin-1 Homo- And Hetero-Oligomerization In Innate Anti-Fungal Immunity, Eduardo U. Anaya

Biomedical Sciences ETDs

Dectin-1A is a C-type Lectin innate immunoreceptor that recognizes β-(1,3)-glucan, a structural component of Candida species cell walls. Dectin-1 has eight alternative splice isoforms including, A and B. Innate immunocytes can express one or both isoforms, but neither their relative responsiveness to β-glucan nor the potential for inter-isoform signaling cross-talk is well understood. In this study, we determine how the different structures of soluble β-glucans affect both isoforms and unravel how differences in glucan structure impact the earliest events in Dectin-1 signaling. Using quantitative microscopy techniques, we explored the role of glucan structure on Dectin-1A oligomerization, which is thought to …

Exploring The Niche Of Rickettsia Montanensis (Rickettsiales: Rickettsiaceae) Infection Of The American Dog Tick (Acari: Ixodidae), Using Multiple Species Distribution Model Approaches, Catherine A. Lippi, Holly Gaff, Alexis L. White, Heidi K. St. John, Allen L. Richards, Sadie J. Ryan

Biological Sciences Faculty Publications

The American dog tick, Dermacentor variabilis (Say) (Acari: Ixodidae), is a vector for several human diseasecausing pathogens such as tularemia, Rocky Mountain spotted fever, and the understudied spotted fever group rickettsiae (SFGR) infection caused by Rickettsia montanensis. It is important for public health planning and intervention to understand the distribution of this tick and pathogen encounter risk. Risk is often described in terms of vector distribution, but greatest risk may be concentrated where more vectors are positive for a given pathogen. When assessing species distributions, the choice of modeling framework and spatial layers used to make predictions are important. …

Assessment Of Grain Safety In Developing Nations, Jose R. Mendoza

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

Grains are the most widely consumed foods worldwide, with maize (Zea mays) being frequently consumed in developing countries where it feeds approximately 900 million people under the poverty line of 2 USD per day. While grain handling practices are acceptable in most developed nations, many developing nations still face challenges such as inadequate field management, drying, and storage. Faulty grain handling along with unavoidably humid climates result in recurrent fungal growth and spoilage, which compromises both the end-quality and safety of the harvest. This becomes particularly problematic where there is little awareness about health risks associated with poor …

Structural Characterization Of Two Large Icosahedral Dna Viruses And Their Capsid Assembly Mechanisms, Yuejiao Xian

Open Access Theses & Dissertations

In the last three decades, many large DNA viruses were discovered and grouped into a loosely defined clade of Nucleocytoplasmic Large DNA Viruses (NCLDVs). NCLDVs infect a wide range of hosts from single cellular protists to large animals. Recently, these viruses were classified as a new phylum of Nucleocytoviricota under the kingdom of Bamfordvirae. The genomes of these Nucleocytoviricota viruses (NCVs) are remarkedly large and complicated, containing many cellular genes from all three domains of life, which raised intensive debates on their evolutionary origins. Despite being classified in the same phylum, their physical structures vary and can be roughly classified …

Molecular Detection Of Host-Specific Fecal Bacteria In Three Major Watersheds Of Piedmont Georgia, Muhammad Amar

Biology Theses

Abstract

Fecal pollution is a major concern in creeks and rivers. The aim of this study was to enumerate fecal coliform bacteria and identify the source of contamination using Microbial Source Tracking at three different creeks (Mountain Oak, Long Cane, and Ulcohatchee) in the Piedmont region of Georgia. Data collected in this research will be used to formulate watershed rehabilitation plans to decrease the transfer of fecal indicator bacteria (FIB) into these creeks. Samples were collected at several sites along the creeks (4 sites at Mountain Oak, 10 sites at Long Cane, and 5 sites at Ulcohatchee). The site locations …

Malaria, Microbes, And Mice: The Role Of The Gut Microbiota On The Immune Response To Plasmodium Infection And The Treatment Potential Of Microbiota Modulation., Morgan L. Waide

Electronic Theses and Dissertations

Plasmodium infection leads to over 200 million cases of malaria and 400,000 deaths worldwide each year. These deaths are largely in children under the age of five and pregnant women [1]. Caused by transmission of Plasmodium parasites by the female Anopheles mosquito, malaria poses a risk for over 40 percent of the world’s population [1]. Despite worldwide efforts to eradicate malaria leading to a decrease in malaria-associated mortalities in the early 2000s [2], growing resistance to the available antimalarials and the lack of an effective, long-lasting vaccine has caused this decrease to plateau in recent years [1, 3-6]. Furthermore, malaria …

A Pharmacological Strategy Against African Sleeping Sickness, Wahaj Zuberi

Dissertations and Theses (Open Access)

Trypanosoma brucei is a parasitic eukaryote and is the causal agent of the disease known as African sleeping sickness, transmitted via the bite of a tsetse fly. If left untreated, the parasite ultimately crosses the blood-brain eventually leading to death. Currently there are 5 approved drugs used to treat it, each with toxic side effects and effective at specific disease stages. A more effective and less toxic drug candidate is highly sought after. The essential enzyme, dUTPase, is an excellent drug target in the parasite while utilizing S. cerevisiae as a model system.

dUTPase is essential in T. brucei (tbdUTPase), …