Molecular Biology Commons^™

A Broadly Distributed, Novel Class Of Diiron Enzymes Involved In Para-Aminobenzoate Synthesis, Joseph M. Zambelas

Senior Theses

The overall structure and ligand arrangement of diiron enzymes influence their function and catalytic potential, allowing for them to catalyze an expansive breadth of high energy transformations. The diiron enzyme CADD from Chlamydia trachomatis is involved in a novel biosynthetic pathway for p-aminobenzoic acid (pABA), a precursor for tetrahydrofolate. The unique ligand structure and reactivity of CADD and homolog NE1434 provide an intriguing means to contrast structure function relationships with other known diiron enzymes that activate dioxygen. In this work, studies of CADD and NE1434 orthologs and comparison to other diiron enzymes reveal several sequence motifs that are likely critical …

Understanding How Human Lipoxygenases Bind Molecular Oxygen And Arachidonic Acid Substrate, Austin Paul Primeaux

Honors Capstones

No abstract provided.

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 …

A Novel Intramolecular Interaction In P53, Fan He

USF Tampa Graduate Theses and Dissertations

The p53 tumor suppressor is a sequence-specific DNA binding protein that activates gene transcription to regulate cell survival and proliferation. The activation process involves post-translational modifications that suppress p53 degradation by MDM2 and increase p53 DNA binding affinity. p53 is mutated in ~50% of human tumors, with higher frequency in specific tumor types and after relapse. Mutated p53 loses transcriptional activity and gains new functions that drive tumor progression. Both N-terminus (NT) and C-terminus (CT) of p53 contain intrinsically disordered regions. The p53 CT has well-documented effects in regulating DNA binding. CT truncated p53 mutants showed defective DNA binding and …

To Mid-Cell And Beyond: Characterizing The Roles Of Gpsb And Ypsa In Cell Division Regulation In Gram-Positive Bacteria, Robert S. Brzozowski

USF Tampa Graduate Theses and Dissertations

The bacterial cell division protein FtsZ is a tubulin homolog that forms a ring-like structure at the site of cell division in most bacterial species. There it acts as a scaffold, aiding in the recruitment of other divisome proteins to the site of cell division. Furthermore, studies focusing on the role of FtsZ treadmilling and septal peptidoglycan synthesis implicates that FtsZ plays a direct role in the ultimate closure of the division septum. Thus, many studies in the field of bacterial cell division have focused on FtsZ in terms of its spatial and temporal regulation as well as its ability …

Metabolic Reprogramming By C-Met Inhibition As A Targetable Vulnerability In Glioblastoma, Trang Thi Thu Nguyen, Enyuan Shang, Georg Karpel-Massler, Markus D. Siegelin

Publications and Research

The elucidation of better treatments for solid tumors and especially malignant glial tumors is a priority. Better understanding of the molecular underpinnings of treatment response and resistance are critical determinants in the success for this endeavor. Recently, a battery of novel tools have surfaced that allow to interrogate tumor cell metabolism to more precise extent than this was possible in the earlier days. At the forefront of these developments are the extracellular flux and carbon tracing analyses. Through utilization of these techniques our group made the recent observation that acute and chronic c-MET inhibition drives fatty acid oxidation that in …

Sunflower Seedlings Fail To Remove Uranium Pollution In The Navajo Nation: Participatory Science As A Path To Build Community And Address Environmental Injustice, Zak R. Webber

Undergraduate Honors Theses

Mid-20th century mining on Naabeehó Bináhásdzo (Navajo Nation) polluted groundwater with high concentrations of uranium and arsenic. The Navajo Nation and other rural residents of this region use groundwater for drinking, livestock, and irrigation. However, many individuals and communities must purchase and transport treated water from locations that are often hours away. Sunflowers have been shown to preferentially take up heavy metals, including uranium and arsenic, potentially representing a tool to improve water quality through on-site, low-cost phytoremediation. We carried out a collaborative research project with a high school class on the Navajo Nation in 2018 and 2019. The students …

Evaluation And Improvement Of A Novel Method For Rapid Promoter Characterization In A Zebrafish Model, Hunter Giles

Undergraduate Honors Theses

This thesis examines a novel technique for characterizing promoters using a zebrafish model. The proximal upstream cis-regulatory elements, also known as promoters or promoter regions, are essential for the precise regulation and timing of gene expression. Often the characterization of these regions relies on imprecise methods involving large deletions or bioinformatic predictions rather than experimental data. However, high-throughput sequencing technology could potentially allow large libraries containing hundreds of thousands of variants of a single promoter to be simultaneously analyzed. We have been working to develop a novel method for promoter characterization that takes advantage of this technology. We tested this …

Cellulolytic Enzymes From The Maize Seed Production System—Characterization, Inhibition, And Novel Activities, Hong Fang

Student Theses and Dissertations

Enzymatic saccharification of ligno-cellulosic material is a key process in advanced biofuel production. Different enzymes are required in the enzymatic saccharification. To meet the large demand of these enzymes for industrial purposes, a transgenic maize seed expression system had been utilized in our laboratory to acquire adequate and cost-effective pure enzymes including β-1,4-endoglucanase, cellobiohydrolase I, cellobiohydrolase II and expansin. In this dissertation, the possibility of utilizing maize-produced recombinant cellulases in promoting the saccharification of ligno-cellulosic material was investigated. From the purification and basic characterization of these target enzymes to the identification of different inhibitors, this project has partially addressed the …

Transcriptomics And Phenomics Analysis Of High Ascorbate Arabidopsis Myo-Inositol Oxygenase Overexpressers, Nirman Nepal

Student Theses and Dissertations

Myo-inositol oxygenase (MIOX) is the first enzyme in the inositol route to ascorbate (L-ascorbic acid, AsA). Over-expression of MIOX in plants leads to elevated AsA content and enhanced growth rate, biomass accumulation, and tolerance to abiotic stresses. In this work, a combination of transcriptomics, phenomics, cell biology, LC-MS/MS, and physiological measurements were used to gain a better understanding of the molecular mechanisms underlying the phenotype of the MIOX lines. Transcriptomic analysis revealed increased expression of genes involved in auxin synthesis, auxin conjugation, hydrolysis, transport, and metabolism, supported by elevated auxin levels both in vitro and in vivo, and confirmed by …

Mixed-Lineage Kinase-3 (Mlk3) Plays A Negative Modulatory Role In Insulin Secretion From The Pancreatic Β-Cell, Tyler Russeth, Vijayalakshmi Thamilselvan, Anjaneyulu Kowluru

Medical Student Research Symposium

Glucose-stimulated insulin secretion (GSIS) from the pancreatic β-cell in response to elevated levels of glucose is controlled by a variety of signals including intracellular calcium and nucleotides such as cAMP, ATP and GTP. These cellular signals are responsible for activation of specific kinases that mediate phosphorylation of key exocytotic proteins that lead to GSIS. In the context of protein kinases, mixed-lineage kinases (MLKs) have been implicated in an assortment of cellular functions, including cell proliferation and apoptosis. However, very little is known on potential regulatory roles of MLKs in islet β-cell function, including GSIS. The goal of this study is …

Functions Of Cdk/Cyclin Complexes In Endoreplication Regulation By The Cdk Inhibitor Siamese, Kai Wang

LSU Doctoral Dissertations

Arabidopsis trichome (leaf hair) is a specialized single cell extended from epidermal cell on the leaves, which is a typical endoreplication and is also known as endoreduplication. Several D-type cyclins were tested to check the cell division in trichome, and the trichome expressing either CYCB1;2 or CDKB2;2 cannot trigger cell division, even if simultaneous expression of CYCB1;2 and CDKB2;2 failed to produce mitosis in trichome. Only CYCD3;1 specifically promotes multicellular trichome. cdkb1;1cdbk1;2 double mutants and sim cdkb1;1cdkb1;2 triple mutants exhibit the phenotype similar to the wild type and very limited cell division respectively. Overexpression of a CDKB1;1 dominant-negative construct that …

Molecular Differentiation Of Astragalus Species And Varieties From The Western United States: The Chloroplast Dna Bridge Between Evolution And Molecular Systematics, Marwa Neyaz, Daniel Cook, Rebecca Creamer

Poisonous Plant Research (PPR)

Locoweeds are the most widespread poisonous plant problem in the world and have been reported in the Western United States since the 1800s, causing tremendous losses in livestock. Consumption of locoweeds by grazing animals stimulates the neurological disease, locoism, characterized by weight loss, ataxia, and lack of muscular coordination. The name locoweed is used for Astragalus and Oxytropis species known to contain swainsonine, the toxic principle produced by the plant endophytic fungus Undifilum. Astragalus includes 2,500-3,000 species and many varieties that have almost identical morphological characteristics that overlap among species, leading to improper identification. Therefore, the aim of this study …

Characterization And Assembly Of The Pseudomonas Aeruginosa Aspartate Transcarbamoylase-Pseudo Dihydroorotase Complex, Chandni Patel, Asmita Vaishnav, Brian Fp Edwards, David R. Evans

Biochemistry and Molecular Biology Faculty Publications

Pseudomonas aeruginosa is a virulent pathogen that has become more threatening with the emergence of multidrug resistance. The aspartate transcarbamoylase (ATCase) of this organism is a dodecamer comprised of six 37 kDa catalytic chains and six 45 kDa chains homologous to dihydroorotase (pDHO). The pDHO chain is inactive but is necessary for ATCase activity. A stoichiometric mixture of the subunits associates into a dodecamer with full ATCase activity. Unlike other known ATCases, the P. aeruginosa catalytic chain does not spontaneously assemble into a trimer. Chemical-crosslinking and size-exclusion chro- matography showed that P. aeruginosa ATCase is monomeric which accounts for its …

A Halogen Bonding Perspective On Iodothyronine Deiodinase Activity, Eric S. Marsan, Craig A. Bayse

Chemistry & Biochemistry Faculty Publications

Iodothyronine deiodinases (Dios) are involved in the regioselective removal of iodine from thyroid hormones (THs). Deiodination is essential to maintain TH homeostasis, and disruption can have detrimental effects. Halogen bonding (XB) to the selenium of the selenocysteine (Sec) residue in the Dio active site has been proposed to contribute to the mechanism for iodine removal. Polybrominated diphenyl ethers (PBDEs) and polychlorinated biphenyls (PCBs) are known disruptors of various pathways of the endocrine system. Experimental evidence shows PBDEs and their hydroxylated metabolites (OH-BDEs) can inhibit Dio, while data regarding PCB inhibition are limited. These xenobiotics could inhibit Dio activity by competitively …

Targeting Trna-Synthetase Interactions Towards Novel Therapeutic Discovery Against Eukaryotic Pathogens, Paul Kelly, Fatemeh Hadi-Nezhad, Dennis Y. Liu, Travis J. Lawrence, Roger G. Linington, Michael Ibba, David H. Ardell

Biology, Chemistry, and Environmental Sciences Faculty Articles and Research

The development of chemotherapies against eukaryotic pathogens is especially challenging because of both the evolutionary conservation of drug targets between host and parasite, and the evolution of strain-dependent drug resistance. There is a strong need for new nontoxic drugs with broad-spectrum activity against trypanosome parasites such as Leishmania and Trypanosoma. A relatively untested approach is to target macromolecular interactions in parasites rather than small molecular interactions, under the hypothesis that the features specifying macromolecular interactions diverge more rapidly through coevolution. We computed tRNA Class-Informative Features in humans and independently in eight distinct clades of trypanosomes, identifying parasite-specific informative features, …

Assessment Of Soil Protein And Refractory Soil Organic Matter Across Two Chronosequences Of Newly Developing Marshes In Coastal Louisiana, Usa, Stuart Alexander Mcclellan

LSU Doctoral Dissertations

The impacts of sea-level rise and hydrologic manipulation are threatening the stability of coastal marshes throughout the world, thereby increasing the potential for re-mineralization of soil organic matter (SOM) in these systems. Such threats have prompted marsh restoration efforts, particularly in coastal Louisiana, yet it is unclear how the slowly decomposing (refractory) and quickly decomposing (labile) fractions of SOM may be differentially affected by different approaches to marsh restoration. Additionally, otherwise labile compounds may accumulate in the soil via a range of protective mechanisms, including rapid burial and association with organic compounds that are thought to enhance soil aggregation, such …

Assessing Population Genetic Structure Of Eastern Phoebes At A Migratory Stopover Site, Daniel Jones

Biology Theses

Migration is an energetically costly and stressful event and migratory stopover sites are important areas along the migratory route that birds stop at to rest and refuel. Migration timing and routes vary across and even within species, including differences between sexes, ages and populations. Most genetic studies of migratory birds occur on breeding grounds, but when breeding locations are not known, it is likely that genetic patterns can be assessed accurately at migratory stopover sites if certain conditions exist. First, if a species is philopatric – where individuals return to the same sites every year, gene flow across geographically separated …

Hur Ubiquitination By Brca1/Bard1 And Its Role In Controlling Gene Expression During Dna Damage Response, Gamage M. Aruggoda

Dissertations, Theses, and Capstone Projects

Despite our understanding of the biochemistry of the BRCA1/BARD1 E3 ligase, we know very little of the mechanism by which its cellular substrates, how they are chosen, how its E3 Ub ligase activity is regulated, which are the cofactors involved in this regulation, and how the substrates are modified during DDR. In this dissertation, I further evaluate BRCA1/BARD1-mediated E3 ligase activity and how CstF-50 and p97 regulate this reaction working as cofactors. My data show that BRCA1/BARD1 is an E3 ligase that ubiquitinates the RNA binding protein Human antigen R(HuR).

HuR is abundant in the nucleus and is transported to …

Identification Of Uncommon Antibiotic-Producing Illinois Soil Isolates, Lesly Muniz, Dr. Lori Scott

Identifying and Characterizing Novel Antibiotic Producing Microbes From the Soil

This project is a collaboration with the Tiny Earth Project Initiative (TEPI), which is a global network of educators and students focused on student sourcing antibiotic discovery from the soil. We researched tester strains B. subtilis and E. coli from the soil isolates obtained. We further verified if the isolates were common antibiotic bacteria. Unfortunately, this project heavily relied on biochemical tests, colony morphology, and Gram stains to reject or fail to reject our hypothesis. Our goal was to discover new antibiotic-producing bacteria that could be beneficial in combating ESKAPE strains. A proper PCR and DNA extraction would be required …