Organisms Commons^™

Candida Albicans Farnesol Synthesis And Secretion, Daniel J. Gutzmann

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

Candida albicans is a polymorphic fungus and opportunistic commensal found primarily in the gastrointestinal and skin of healthy individuals. Several barriers prevent C. albicans from causing disease including a healthy immune system and microbiome. When these barriers become comprised, C. albicans can transition to a pathogen and disseminate through the intestinal mucosa leading to life-threatening bloodstream and invasive infections with mortality rates of up to 64%. Morphogenic plasticity is key to this transition and impacts virulence, adaptation to different host environments, and evasion of host immune responses. One regulator of morphogenesis is farnesol. Farnesol is a secondary metabolite of …

Investigating The Abilities Of Potentially Beneficial Bacteria For Increasing Nitrogen-Use Efficiency In Maize, Lexie R. Foster

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

Global agriculture relies heavily on the use of synthetic nitrogen fertilizer to meet the current global food demand. Unfortunately, the average nitrogen-use efficiency (NUE) of maize (Zea mays) is approximately 50 percent. Improving the NUE of maize is essential for meeting the growing global food demand while also decreasing the negative environmental impacts caused by losses of nitrogen fertilizer due to runoff and volatilization. Harnessing the symbiotic relationship between plants and the soil microbiome may be one method for increasing the NUE in crops such as maize. In the present study, a set of potentially beneficial bacterial species …

The Developmental Process For Adenoviral Vectored Canine Influenza Vaccines, Nicholas Jeanjaquet

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

Canine Influenza Virus (CIV) is a recently emerged branch of Influenza A virus that is highly infectious in dogs. The first strain was isolated in 2003, and it has quickly become endemic in areas with dense dog populations, most notably in Asia. The proximity of dogs to humans, along with their potential to serve as mixing vessels for reassortment, raises concern for possible zoonotic transmission and a potential human pandemic. Available vaccines are not frequently updated and struggle to prevent the spread of currently circulating strains. This highlights the need for a new and more effective vaccine. We outline the …

Discovering Novel Polyextremotolerant Fungi And Determining Their Ecological Role Within The Biological Soil Crust Consortium, Erin C. Carr

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

The ecological niche of polyextremotolerant fungi within oligotrophic ecosystems such as biological soil crusts has not yet been determined. These fungi persist in locations where nutrients are depleted while simultaneously surrounded by autotrophic microbes such as algae and cyanobacteria. Yet it has not been shown that they are engaging in any exchange of nutrients the way lichens do. However, there is seemingly no other way for these fungi to obtain vital nutrients, such as carbon or nitrogen, other than from these microbes. Here we have isolated polyextremotolerant fungi from cold desert biological soil crusts which are a microbial biofilm that …

Dgts Production As A Phosphate Starvation Response In The Human Fungal Pathogen Candida Albicans, Caleb J. Wehling

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

Betaine lipids are a class of membrane lipids with betaine head groups. Three betaine lipids are known: diacylglyceryltrimethylhomoserine (DGTS), diacylglycerylhydroxymethylalanine (DGTA), and diacylglycerylcarboxymethylcholine (DGCC). Betaine lipids are most common in algae, although DGTS, the most common betaine lipid, is also found in many bacteria and fungi. Organisms which produce betaine lipids (especially DGTS) often don’t produce phosphatidylcholine (PtdCho), and DGTS structure resembles PtdCho structure without any phosphorous, leading to the hypothesis that betaine lipids may substitute for phospholipids in some organisms. This has been confirmed by discoveries that some organisms are capable of switching their membrane composition from PtdCho to …

Regulation Of Vaccinia Virus Replication: A Story Of Viral Mimicry And A Novel Antagonistic Relationship Between Vaccinia Kinase And Pseudokinase, Annabel T. Olson

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

Poxviruses employ sophisticated signaling pathways that thwart cellular defense mechanisms and simultaneously ensure viral factors are modulated properly. Yet, our understanding of these complex signaling networks are incomplete. For example, the vaccinia B1 kinase plays a vital role in inactivating the cellular antiviral factor BAF, and is suggested to orchestrate other pathways. B1 is highly conserved among poxviruses and exhibits a remarkable degree of similarity to VRKs, a family of cellular kinases, suggesting that the viral enzyme has evolved to mimic VRK activity. Indeed, B1 and VRKs have been demonstrated to target a shared substrate, the DNA binding protein BAF, …

Establishing Benchmark Criteria For Single Chromosome Bacterial Genome Assembly, Timothy J. Krause

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

Adequate recommendations for the amount and types of sequencing data necessary to optimize the recovery of single chromosomes from bacterial sequencing projects do not exist. Broad estimates for coverage depths needed to recover complete bacterial genomes are present in the literature, but required sequencing depths across bacterial and archaeal phylogenies needed for high-quality assembly are not known. Additionally, correlations between genomic complexity and expected quality of assembly have not been properly defined. Furthermore, the capabilities of multiplexing (sequencing more than one sample simultaneously on one flow cell) with long-read sequencing platforms in order to recover complete bacterial chromosomes are poorly …

Contributions Of The Gp120 Variable Loops To Envelope Glycoprotein Trimer Stability In Primate Lentiviruses, Dane M. Bowder

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

Human Immunodeficiency Virus (HIV) is the etiological agent of AIDS and is responsible for the AIDS pandemic worldwide. According to UNAIDS, as of 2016, there were approximately 36.7 million people living with HIV globally, and 1.8 million new infections that year. While antiretroviral therapies and education continue to reduce these numbers, a preventative vaccine is still required to curb this epidemic. The envelope glycoprotein trimer of HIV, which is the sole protein on the surface of the virus and facilitates entry of the virus into host cells, is of keen interest to the HIV vaccine and drug-development field. Recently, the …

Evaluation Of A Human Papillomavirus Genotyping Assay For Cervical Cancer Screening In Tanzania, Kandali S. Kapie

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

Abstract: Mucosal high-risk Human papillomavirus (HR-HPV) has been identified as the primary factor in causing cervical cancer, the most common cancer in women of low and middle-income countries (LMICs). Cervical cancer screening, incorporating the HPV test shown to be more advantageous than screening by visual inspection with acetic acid (VIA) alone. However, due to resources constrain these countries could not afford the available HPV tests. We, therefore, validated a cost-effective Multiplex PCR HPV (mPCR) assay, a recently developed assay for detecting sixteen genital HPV, fourteen HR-HPV and 2 low-risk genotypes. We postulate that this HPV multiplex assay will be at …

Relationship Between Morphogenesis And Secretion In The Filamentous Fungus Aspergillus Nidulans, Lakshmi Preethi Yerra

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

Filamentous fungi have a long history in biotechnology for the production of food ingredients, pharmaceuticals and enzymes. The advancements made in recent years have earned filamentous fungi such as Aspergillus species a dominant place among microbial cell factories. Although the model fungus A. nidulans has been extensively studied, the genetic and regulatory networks that underlie morphogenesis and development have yet to be fully characterized. The Rho GTPases (Cdc42 and RacA) are one of the most important regulators of the morphogenetic processes among diverse eukaryotic organisms. Although the functions of these GTPases are relatively well-characterized, little is known about their …

No Nonsense: The Protection Of Wild-Type Mrnas From Nonsense-Mediated Mrna Decay In Saccharomyces Cerevisiae, Krista D. Patefield

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

Gene regulation in eukaryotes is tightly controlled at multiple levels to ensure proper expression and cellular homeostasis. Misregulation of gene expression is a common source of genetic disease. One mechanism by which cells are able to control gene expression is through the synthesis and degradation of the mRNA molecules encoding the genes. The transcription and degradation of mRNA molecules controls the pool mRNAs that are available to the translational machinery. One of the well-studied mRNA decay pathways is the Nonsense-Mediated mRNA Decay pathway (NMD). Originally, NMD was discovered as a posttranscriptional mRNA surveillance mechanism responsible for the deadenylation-independent decapping and …

Expansion Of The Chlorovirus Genus By Studies On Virus Natural History And Chlorella Host Metabolism, Cristian F. Quispe

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

Inland waters cover about 2.5 percent of our planet and harbor huge numbers of known and unknown microorganisms including viruses. Viruses likely play dynamic, albeit largely undocumented roles in regulating microbial communities and in recycling nutrients in the ecosystem. Phycodnaviruses are a genetically diverse, yet morphologically similar, group of large dsDNA-containing viruses (160- to 560-kb) that inhabit aquatic environments. Members of the genus Chlorovirus are common in freshwater. They replicate in eukaryotic, single-celled, chlorella-like green algae that normally exist as endosymbionts of protists in nature. Very little is known about the natural history of the chloroviruses and how they achieve …

The Epidemiology Of Human Herpesvirus-8: Transmission Of Infection To Children In Zambian Households, Kay L. Crabtree

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

Human Herpes virus-8 (HHV-8) is the known etiologic agent for several malignant pathologies, including Kaposi’s sarcoma (KS), the most common tumor in children in sub-Saharan Africa. Saliva is implicated as the culprit of transmission; however there is a paucity of information regarding transmission to young children. In this study, we investigated the hypothesis that household behaviors exposing the susceptible child to saliva increase the risk of transmission of HHV-8 to that child.

To test our hypothesis a large prospective cohort study in Lusaka, Zambia, enrolling 464 young children and their households, was followed for 48 months. Socio-demographics, health histories, feeding …

Regulation Of Morphogenesis In Filamentous Fungi, Haoyu Si

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

One of the distinguishing features of fungal cells is their highly polarized model of growth. Both yeast cells and hyphal cells grow by cell surface expansion at specified cortical sites. Although the same general mechanisms are likely to be involved in controlling the establishment of hyphal polarity in budding yeast and filamentous fungi, it is noticeable that hyphal cells are organized in a fundamentally different manner to yeast dells. For example, hyphal cells organize formins, septins and actins at the division site while simultaneously retain the same machinery at the tip; whereas yeast cells undergo a transient period of isotropic …