Biochemistry, Biophysics, and Structural Biology Commons^™

Investigating The Role Of Cnag_05113 In The Carnitine Biosynthesis Pathway In Cryptococcus Neoformans., Jasmine Meltzer, Rodrigo Catalan-Hurtado, Perry Kezh, Kerry Smith

Honors College Theses

Cryptococcus neoformans, the leading cause of fungal meningitis, is a fungal pathogen that causes severe infection of the central nervous system in patients with compromised immune systems, typically caused by HIV/AIDS. C. neoformans infections are present in developed countries including the United States, but most fatalities occur in sub-Saharan Africa where antiretroviral therapy, the treatment for HIV/AIDS, is less accessible. Current treatments for severe cryptococcal infections are extensive and outdated. There is a critical need for an improved understanding of the fungus and new targeted therapies. Our goal is to identify metabolic pathways important to the survival of C. …

The Role Of Fto, A Human Rna Demethylase In Perennial Grass Development And Abiotic Stress Responses, Andrew Fiorentino, Qian Hu, Xiaotong Chen, Zhaohui Chen

Honors College Theses

The integration of the human fat mass and obesity associated (FTO) gene into turfgrass is a novel approach at improving cell proliferation and abiotic stress resistance. The FTO protein is an RNA demethylase responsible for epigenetic regulation of the genome. In related rice, the gene is associated with increased crop yield, tiller number, and aerial biomass. It is proposed to work via demethylation of repeat RNA associated with chromatin remodeling, causing widespread transcriptional activation. In this study, the feasibility of using FTO for plant trait modification in perennial grasses is being investigated. Potentially transformed embryogenic calli of creeping bentgrass with …

Methyltransferase, Glucose Adaptation, And Import Complex In Trypanosoma Brucei, Emily Knight

All Dissertations

Trypanosoma brucei is a kinetoplastid parasite responsible for human African trypanosomiasis (HAT) and nagana, a livestock wasting disease, which both endemic to sub-Saharan Africa. Unique to kinetoplastids are the specialized peroxisomes, named glycosomes, which compartmentalize the first several steps of glycolysis and gluconeogenesis, nucleotide sugar biosynthesis, and many other metabolic processes. Kinetoplastids are unique in that they have a single mitochondrion. In this work, I present the first study into SET domain proteins in any kinetoplastid parasites. We have characterized a predicted SET domain protein, TbSETD3, that localizes to the mitochondrion and a depletion of the protein results in growth …

Acetate Metabolism In The Fungal Pathogen Cryptococcus Neoformans, Oly Ahmed

All Dissertations

Cryptococcus neoformans is an environmental basidiomycetous fungus with a worldwide distribution and a wide range of habitats. Inhalation of the desiccated yeasts or spores of C. neoformans often leads to opportunistic pulmonary infections in immunocompromised individuals, and in severe cases causes lethal meningitis following hematogenous dissemination. During infection, depending on the tissue and disease state, the invading fungi experience a range of nutrient microenvironments within the host body. As a result, rapid metabolic adaptations geared towards efficient utilization of carbon sources alternative to glucose become one of the prime determinants of survival and growth for the pathogen. Incidentally, cryptococcal infection …

Heat Stress Response And Excystation In Entamoeba Histolytica, Irem Bastuzel

All Dissertations

Entamoeba histolytica is a water- and food-borne intestinal protozoan parasite that causes amoebiasis and liver abscess and is responsible for symptomatic disease in approximately 100 million people each year leading to ~ 100,000 deaths. The most common disease transmission follows the oral-fecal route, but it can also be transmitted by mechanical vectors such as animals carrying the amoeba from contaminated sources to water systems. In rare cases, disease transmission has been recorded in some patients in which men-to-men sexual practices were preferred.

The life cycle of E. histolytica starts through ingestion of infectious cysts, which are non-dividing, quadri-nucleated structures surrounded …

Investigating The Biochemical Properties Of A Novel Mutation, A194v, In Human Rad51, Briana Vollbeer

All Theses

DNA double-strand breaks (DSB) are one of the most serious DNA lesions because improper repair of a DSB can lead to loss of heterozygosity, aneuploidy, and cancer. One of the primary pathways to repair DSBs is homologous recombination (HR). HR resects the DNA around the DSB and then uses homologous DNA as a template to restore the broken sequence. RAD51 has a vital function in this pathway by forming a nucleoprotein filament on a resected end of the DSB. The nucleoprotein filament searches for homology within the homologous DNA. Once homology is located, strand invasion followed by strand exchange occurs. …

Modeling Electrostatics In Molecular Biology And Its Relevance With Molecular Mechanisms Of Diseases, Mahesh Koirala

All Dissertations

Electrostatics plays an essential role in molecular biology. Modeling electrostatics in molecular biology is complicated due to the water phase, mobile ions, and irregularly shaped inhomogeneous biological macromolecules. This dissertation presents the popular DelPhi package that solves PBE and delivers the electrostatic potential distribution of biomolecules. We used the newly developed DelPhiForce steered Molecular Dynamics (DFMD) approach to model the binding of barstar to barnase and demonstrated that the first-principles method could also model the binding. This dissertation also reflects the use of existing computational approaches to model the effects of Single Amino Acid Variations (SAVs) to reveal molecular mechanisms …

Characterization Of A Potential Glucose Transporter In Trypanosoma Brucei, Matthew Morgan

All Theses

Trypanosoma brucei, the African trypanosome, is an organism heavily dependent on glucose for ATP production during the infectious stage of its life cycle. Here, we have explored the role of an uncharacterized protein designated “novel glucose transporter” (NGT) as a potential glucose transporter. Sequence analyses suggests that NGT shares similarities (either at the primary sequence level or structurally) with Trypanosome Hexose Transporters 1 (TbTHT1), and human GLUT3, both of which are membrane sugar transporters. NGT was localized by fluorescence microscopy to subcellular structures consistent with lysosomes. Silencing NGT expression with RNA interference in parasites resulted in a growth defect …

Discovery Of Genomic Variations By Whole-Genome Resequencing Of The North American Araucana Chicken, Rooksana E. Noorai, Vijay Shankar, Nowlan H. Freese, Christopher M. Gregorski, Susan C. Chapman

Publications

Gallus gallus (chicken) is phenotypically diverse, with over 60 recognized breeds, among the myriad species within the Aves lineage. Domestic chickens have been under artificial selection by humans for thousands of years for agricultural purposes. The North American Araucana (NAA) breed arose as a cross between the Chilean “Collonocas” that laid blue eggs and was rumpless and the “Quetros” that had unusual tufts but with tail. NAAs were introduced from South America in the 1940s and have been kept as show birds by enthusiasts since then due to several distinctive traits: laying eggs with blue eggshells, characteristic ear-tufts, a pea …

Glucose Signaling Is Important For Nutrient Adaptation During Differentiation Of Pleomorphic African Trypanosomes, Yijian Qiu, Jillian E. Milanes, Jessica A. Jones, Rooksana E. Noorai, Vijay Shankar, James C. Morris

Publications

The African trypanosome has evolved mechanisms to adapt to changes in nutrient availability that occur during its life cycle. During transition from mammalian blood to insect vector gut, parasites experience a rapid reduction in environmental glucose. Here we describe how pleomorphic parasites respond to glucose depletion with a focus on parasite changes in energy metabolism and growth. Long slender bloodstream form parasites were rapidly killed as glucose concentrations fell, while short stumpy bloodstream form parasites persisted to differentiate into the insect-stage procyclic form parasite. The rate of differentiation was lower than that triggered by other cues but reached physiological rates …

Ectopic Expression Of A Cyanobacterial Flavodoxin In Creeping Bentgrass Impacts Plant Development And Confers Broad Abiotic Stress Tolerance, Zhigang Li, Shuangrong Yuan, Haiyan Jia, Fangyuan Gao, Qian Hu, Dongfa Sun, Hong Luo

Publications

Flavodoxin (Fld) plays a pivotal role in photosynthetic microorganisms as an alternative electron carrier flavoprotein under adverse environmental conditions. Cyanobacterial Fld has been demonstrated to be able to substitute ferredoxin (Fd) of higher plants in most electron transfer processes under stressful conditions. We have explored the potential of Fld for use in improving plant stress response in creeping bentgrass (Agrostis stolonifera L.). Overexpression of Fld altered plant growth and development. Most significantly, transgenic (TG) plants exhibited drastically enhanced performance under oxidative, drought and heat stress as well as nitrogen (N) starvation, which was associated with higher water retention and …

Tackling Adverse Environment—Molecular Mechanism Of Plant Stress Response And Biotechnology Tool Development, Ning Yuan

All Dissertations

Abiotic and biotic stresses such as drought, salt, nutrition starvation, and pathogen infection are major factors threatening our agricultural production. With the rapidly increasing population and limited arable land area, genetic engineering of crops for new products with more stable and higher yield than conventional cultivars under adverse environment provides a powerful new tool for use in developing novel GMOs (Genetically Modified Organisms) to feed the large population in the immediate future. To develop novel GMOs with enhanced performance under adverse conditions, we need first to understand molecular mechanisms underlying plant stress response. To better understand how signaling transduction pathway …

Heterologous Expression Of A Rice Mir395 Gene In Nicotiana Tabacum Impairs Sulfate Homeostasis, Ning Yuan, Shuangrong Yuan, Zhigang Li, Dayong Li, Qian Hu, Hong Luo

Publications

Sulfur participates in many important mechanisms and pathways of plant development. The most common source of sulfur in soil –SO₄²⁻– is absorbed into root tissue and distributed into aerial part through vasculature system, where it is reduced into sulfite and finally sulfide within the subcellular organs such as chloroplasts and mitochondria and used for cysteine and methionine biosynthesis. MicroRNAs are involved in many regulation pathways by repressing the expression of their target genes. MiR395 family in Arabidopsis thaliana has been reported to be an important regulator involved in sulfate transport and assimilation, and a high-affinity sulphate transporter …

Phosphotransacetylase And Xylulose 5-Phosphate/Fructose 6-Phosphate Phosphoketolase: Two Eukaryotic Partners Of Acetate Kinase, Tonya Taylor

All Dissertations

Although acetate is a predominant metabolite produced by many eukaryotic microbes, far less attention has been given to acetate metabolism in eukaryotes than in bacteria and archaea. Acetate kinase (Ack), which catalyzes the reversible phosphorylation of acetate from ATP, is a key enzyme in bacterial acetate metabolism. Ack primarily partners with phosphotransacetylase (Pta), which catalyzes the generation of acetyl phosphate from acetyl-CoA, but can also partner with xylulose 5-phosphate/fructose 6-phosphate phosphoketolase (Xfp), which produces acetyl phosphate from either xylulose 5-phosphate or fructose 6-phosphate. The Ack-Pta pathway, found primarily in bacteria, is also present in lower eukaryotes such as the green …

Probing The Effects Of Tbhk2 On Trypanosoma Brucei Growth, Social Growth, And Inhibitor Response, Amber Hackler, William Mcalpine, Yijian Qiu, James Morris

Graduate Research and Discovery Symposium (GRADS)

In sub-Saharan Africa the protozoan parasite, Trypanosoma brucei, continues to be of major concern for the health and economic development of the region. This parasite is known to cause human African trypanosomiasis (HAT or African sleeping sickness) and nagana in livestock such as cattle. Social behaviors, such as colonization and migration, are important in the study of T. brucei because of the way the parasite infects its mammalian host. During the fly bloodmeal, the parasite first passes into the gut but then eventually migrates to the fly salivary glands where it will continue to develop before transmission as a parasitic …