Biochemistry, Biophysics, and Structural Biology Commons^™

Structural Basis For The Substrate Inhibition Of Proline Utilization A By Proline, David A. Korasick, Travis A. Pemberton, Benjamin W. Arentson, Donald F. Becker, John J. Tanner

Department of Biochemistry: Faculty Publications

Proline utilization A (PutA) is a bifunctional flavoenzyme that catalyzes the two-step oxidation of L-proline to L-glutamate using spatially separated proline dehydrogenase (PRODH) and L-glutamate-y-semialdehyde dehydrogenase (GSALDH) active sites. Substrate inhibition of the coupled PRODH-GSALDH reaction by proline is a common kinetic feature of PutAs, yet the structural basis for this phenomenon remains unknown. To understand the mechanism of substrate inhibition, we determined the 2.15 Å resolution crystal structure of Bradyrhizobium japonicum PutA complexed with proline. Proline was discovered in five locations remote from the PRODH active site. Most notably, strong electron density indicated that proline bound tightly to the …

Lncrna Meg3 Protects Endothelial Function By Regulating The Dna Damage Response, Mohamed Sham Shihabudeen Haider Ali, Xiao Cheng, Matthew Moran, Stefan Haemmig, Michael J. Naldrett, Sophie Alvarez, Mark W. Feinberg, Xinghui Sun

Department of Biochemistry: Faculty Publications

The role of long non-coding RNAs (lncRNAs) in regulating endothelial function through the DNA damage response (DDR) remains poorly understood. In this study, we demonstrate that lncRNA maternally expressed gene 3 (Meg3) interacts with the RNA binding protein polypyrimidine tract binding protein 3 (PTBP3) to regulate gene expression and endothelial function through p53 signaling a major coordinator of apoptosis and cell proliferation triggered by the DDR. Meg3 expression is induced in endothelial cells (ECs) upon p53 activation. Meg3 silencing induces DNA damage, activates p53 signaling, increases the expression of p53 target genes, promotes EC apoptosis, and inhibits EC proliferation. Mechanistically, …

Long-Chain Omega-3 Polyunsaturated Fatty Acids Modulate Mammary Gland Composition And Inflammation, Saraswoti Khadge, Geoffrey M. Thiele, J. Graham Sharp, Timothy R. Mcguire, Lynell W. Klassen, Paul N. Black, Concetta Dirusso, James Talmadge

Department of Biochemistry: Faculty Publications

Studies in rodents have shown that dietary modifications as mammary glands (MG) develop, regulates susceptibility to mammary tumor initiation. However, the effects of dietary PUFA composition on MGs in adult life, remains poorly understood. This study investigated morphological alterations and inflammatory microenvironments in the MGs of adult mice fed isocaloric and isolipidic liquid diets with varying compositions of omega (ω)-6 and long-chain (Lc)-ω3FA that were pair-fed. Despite similar consumption levels of the diets, mice fed the ω-3 diet had significantly lower body-weight gains, and abdominal-fat and mammary fat pad (MFP) weights. Fatty acid analysis showed significantly higher levels of Lc-ω-3FAs …

Dietary Omega-3 And Omega-6 Polyunsaturated Fatty Acids Modulate Hepatic Pathology, Saraswoti Khadge, J. Graham Sharp, Geoffrey M. Thiele, Timothy R. Mcguire, Lynell W. Klassen, Michael J. Duryee, Holly C. Britton, Jordan Beck, Paul N. Black, Concetta Dirusso, James Talmadge

Department of Biochemistry: Faculty Publications

Recent evidence has suggested that dietary polyunsaturated fatty acids (PUFAs) modulate inflammation; however, few studies have focused on the pathobiology of PUFA using isocaloric and isolipidic diets and it is unclear if the associated pathologies are due to dietary PUFA composition, lipid metabolism or obesity, as most studies compare diets fed ad libitum. Our studies used isocaloric and isolipidic liquid diets (35% of calories from fat), with differing compositions of omega (ω)-6 or long chain (Lc) ω-3 PUFA that were pair-fed and assessed hepatic pathology, inflammation and lipid metabolism. Consistent with an isocaloric, pair-fed model we observed no significant difference …

Adenosine Has Two Faces: Regionally Dichotomous Adenosine Tone In A Model Of Epilepsy With Comorbid Sleep Disorders, Ted J. Warren, Timothy A. Simeone, D. David Smith, Ryan Grove, Jiri Adamec, Kaeli K. Samson, Harrison M. Roundtree, Deepak Madhavan, Kristina A. Simeone

Department of Biochemistry: Faculty Publications

Objective: Adenosine participates in maintaining the excitatory/inhibitory balance in neuronal circuits. Studies indicate that adenosine levels in the cortex and hippocampus increase and exert sleep pressure in sleep-deprived and control animals, whereas in epilepsy reduced adenosine tone promotes hyperexcitability. To date, the role of adenosine in pathological conditions that result in both seizures and sleep disorders is unknown. Here, we determined adenosine tone in sleep and seizure regulating brain regions of Kv1.1 knockout (KO) mice, a model of temporal epilepsy with comorbid sleep disorders.

Methods: 1) Reverse phase-high performance liquid chromatography (RP-HPLC) was performed on brain tissue to determine levels …

A Behavioral Mechanistic Investigation Of The Role Of 5-Ht1a Receptors In The Mediation Of Rat Maternal Behavior, Xiaonan Li, Xiaojing Ding, Ruiyong Wu, Leilei Chen, Jun Gao, Gang Hu, Ming Li

Department of Psychology: Faculty Publications

Previous work suggests that 5-HT_1A receptors play a special role in rodent maternal aggression, but not in other aspects of maternal care (e.g. pup retrieval and nest building). The present study re-assessed the basic effects of 5-HT_1A activation or blockade on various maternal responses in postpartum female rats. We also examined the possible behavioral mechanisms underlying the maternal effects of 5-HT_1A. Sprague–Dawley mother rats were injected with a 5-HT_1A agonist 8-OH-DPAT (0.1, 0.5 or 1.0 mg/kg, sc), a 5-HT_1A antagonist WAY-101405 (0.1, 0.5 or 1.0 mg/kg, sc) or 0.9% saline solution on postpartum days …

Microstructural Changes To Proso Millet Protein Bodies Upon Cooking And Digestion, Paridhi Gulati, You Zhou, Christian Elowsky, Devin J. Rose

Department of Food Science and Technology: Faculty Publications

Cooking results in a drastic decline in digestibility of proso millet proteins, panicins. Scanning electron and confocal microscopy were used to observe morphological changes in proso millet protein bodies upon cooking and digestion that could be associated with the loss in digestibility. Spherical protein bodies (1–2.5 mm) were observed in proso millet flour and extracted protein. Cooking did not result in any noticeable change in the size or shape of the protein bodies. However, upon digestion with pepsin the poor digestibility of cooked proso millet protein was clearly evident from the differences in microstructure of the protein bodies: large cavities …

การพัฒนาอุปกรณ์วิเคราะห์ฐานกระดาษสำหรับหาปริมาณสารเพรดนิโซโลนและเดกซาเมทาโซนที่ปลอมปนในผลิตภัณฑ์สมุนไพรด้วยวิธีเคมีไฟฟ้า, วิศรุต พริ้มพราย

Chulalongkorn University Theses and Dissertations (Chula ETD)

การปลอมปนของสารสเตียรอยด์ชนิดเดกซาเมทาโซนและเพรดนิโซโลนในผลิตภัณฑ์สมุนไพรเป็นปัญหาสำคัญที่ก่อผลเสียร้ายแรงต่อสุขภาพของผู้ใช้ ในหลาย ๆ ประเทศทั่วโลก โดยเฉพาะอย่างยิ่งในประเทศกำลังพัฒนา งานวิจัยนี้ ประสบความสำเร็จในการพัฒนาอุปกรณ์สำหรับแยกและตรวจวัดปริมาณการปลอมปนของสารสเตียรอยด์ดังกล่าว โดยใช้อุปกรณ์ตรวจวิเคราะห์ฐานกระดาษและใช้หลักการทางเคมีไฟฟ้า (electrochemical paper-based analytical device หรือ ePAD) ซึ่งประกอบด้วยกระดาษ Whatman SG81 ตลับพลาสติกจากการพิมพ์สามมิติ และขั้วไฟฟ้าชนิด screen printed electrode โดยกระดาษ Whatman SG81 ใช้สำหรับแยกสารสเตียรอยด์ชนิดเดกซาเมทาโซนและเพรดนิโซโลน โดยใช้วัฏภาคเคลื่อนที่เป็นสารละลาย 60% ethyl acetate ใน cyclohexane ซึ่งผลการศึกษาพบว่าสามารถแยกสารสเตียรอยด์ดังกล่าวออกจากสิ่งเจือปนต่าง ๆ ได้ภายใน 7 นาที สารสเตียรอยด์ที่แยกออกจากกันบนกระดาษ นำมาวัดปริมาณด้วยเทคนิคเคมีไฟฟ้าชนิด differential pulse voltammetry โดยใช้ตลับพลาสติกจากการพิมพ์สามมิติที่ถูกออกแบบทำให้สารละลายอิเล็กโทรไลต์ถูกขังอยู่บนกระดาษ ทำให้สามารถตรวจวัดสัญญาณทางเคมีไฟฟ้าได้คงที่ ซึ่งอุปกรณ์ที่พัฒนาขึ้นสามารถตรวจวัดปริมาณปลอมปนของสารสเตียรอยด์ทั้งชนิดเดกซาเมทาโซนและ เพรดนิโซโลนได้ในช่วงความเข้มข้นระหว่าง 10 ถึง 500 µg/mL โดยมีค่าสัมประสิทธิ์สหสัมพันธ์เท่ากับ 0.988 และ 0.994 ตามลำดับ มีขีดจำกัดในการตรวจวิเคราะห์เชิงคุณภาพเท่ากับ 3.59 µg/mL และ 6.00 µg/mL ตามลำดับ และขีดจำกัดในการตรวจวิเคราะห์เชิงปริมาณมีค่าเท่ากับ 11.98 µg/mL และ 20.02 µg/mL ตามลำดับ การตรวจวัดปริมาณปลอมปนของสารสเตียรอยด์ทั้งสองชนิดในสิ่งตัวอย่างผลิตภัณฑ์สมุนไพรจริงด้วยวิธีที่พัฒนาขึ้นมีค่าสอดคล้องกับผลที่ตรวจด้วยวิธี HPLC และเป็นวิธีที่ใช้งานง่าย มีต้นทุนต่ำ รวดเร็ว และมีศักยภาพนำไปใช้ตรวจหาสิ่งตัวอย่างผลิตภัณฑ์สมุนไพรที่สงสัยว่ามีการปลอมปนของสารสเตียรอยด์ ในระดับภาคสนาม

Wnt Secretion Proteins Modulate Rankl-Induced Expression Of Aire In Thymic Epithelial Cells, Daniel Pollack

Dissertations and Theses

Thymic epithelial cells (TEC) are essential for a proper adaptive immune response by regulating thymocyte development and establishing central tolerance. In the thymus, TECs differentially express Wnt proteins, which activate canonical and non-canonical Wnt signaling pathways. Wnt signaling is thought to regulate cell survival, proliferation, and development although the direct molecular mechanisms in TECs have yet to be elucidated. The inducible inhibition of canonical Wnt signaling with Dkk1 leads to a rapid loss of TEC progenitors as well as a decline in mature Aire-expressing mTECs. Therefore, we explore the role of Wnt ligands potentially responsible for stimulating and/or regulating Wnt …

Rep-Dna Complexes And Their Role In Aav Dna Transactions, Vishaka Santosh

Theses and Dissertations

Adeno-associated Virus (AAV) Rep proteins are multifunctional proteins that carry out various DNA transactions required for the life cycle of AAV. The Rep proteins have been found to be important for genome replication, gene regulation, site-specific integration and play an essential role in genome packaging. There are two main groups of Rep proteins: large and small Reps; both groups are SF3 helicase family members. During DNA packaging, studies have shown that the small Rep proteins are critical to produce fully packed particles. Using stopped-flow kinetic analysis, we show a significant difference in helicase activity between the small and large Rep …

Quantitation Without Calibration: Response Profile As An Indicator Of Target Amount, Mrittika Debnath

Graduate Research Theses & Dissertations

Quantitative assessment of biomarkers is essential in numerous contexts from decision-making in clinical situations to food quality monitoring to the interpretation of life-science research findings. However, appropriate quantitation techniques are not as widely addressed as detection methods. One of the major challenges in biomarker’s quantitation is the need to have a calibration for correlating a measured signal to a target amount. The step complicates the methodologies and makes them less sustainable. In this work, we addressed the issue via a new strategy: relying on the position of response profile rather than absolute signal for assessment of a target nucleic acid’s …

Quantifying The Differences In Binding Affinity Of Reduced Glutathione For Glutathione S-Transferase At Ph 6.5 And 8.5 Using Isothermal Titration Calorimetry, Clay P. Renshaw Jr., Ronald K. Gary

McNair Poster Presentations

The binding affinity between an enzyme and its substrate is often dependent on the pH of the local environment. Knowing the pH at which reduced glutathione (GSH) binds with the highest affinity to the enzyme glutathione S-transferase (GST) is useful for determining the optimal pH for purification of GST-fusion proteins during GST-affinity chromatography. In this study, GST of the species Schistosoma japonicum was purified, quantified, and utilized to study its binding interaction with GSH at pH 6.5 and 8.5 via isothermal titration calorimetry (ITC). After protein expression, extraction, and purification, the GST concentration was quantified using Qubit^TM fluorometry. …

Synthesis, Characterisation And Dna Intercalation Studies Of Regioisomers Of Ruthenium (Ii) Polypyridyl Complexes, Laura Perdisatt, Samar Moqadasi, Luke O'Neill, Gary Hessman, Alessandra Ghion, Muhammad Qasim Mushtaq Warraich, Alan Casey, Christine O'Connor

Articles

Regioisomers of the functional group of the main ligand (L) on a series of [Ru(phen)2L]2+and [Ru(bpy)2L]2+ complexes, where phen is 1,10 phenanthroline and bpy is 2,2′-bipyridine, were synthesised to investigate the interaction with deoxyribonucleic acid (DNA) as potential therapeutics. UV–Vis binding titrations, thermal denaturation and circular dichroism were used to evaluate their interaction with DNA. The conclusions indicated the significance of the auxiliary ligand; especially 1,10-phenanthroline has on the binding constants (Kb). The systematic variation of auxiliary ligand(phen or bpy), and polypyridyl ligand (4-(1H-Imidazo[4,5-f][1,10]phenanthrolin-2-yl)benzonitrile (CPIP), 2-(4-formylphenyl)imidazo[4,5-f] [1,10] phenanthroline (FPIP), 2-(4-bromophenyl)imidazo[4,5-f][1,10]phenanthroline (BPIP) and 2-(4-nitrophenyl)imidazo[4,5-f] [1,10] phenanthroline (NPIP), split in terms of …

Determining The Role Played By Aryl Hydrocarbon Receptor (Ahr) In The Colon Carcinoma Tumor Model, Poonam Yakkundi

University of the Pacific Theses and Dissertations

Aryl hydrocarbon receptor (AHR), commonly known as an environmental sensor involved in the metabolism and elimination of xenobiotic substances, is also an important modulator in the development and functioning of the immune system. AHR expression is varied in the T cell subsets with the highest expression in T-helper 17 and T regulatory cells. Work from many researchers has suggested that AHR can act as a tumor promoter or a tumor suppressor depending on the tumor type. Our goal is to understand the role played by AHR in MC38 syngeneic colon carcinoma tumor model. In the absence of AHR, MC38 tumor …

Characterization Of Tetraethyl Orthosilicate-Based Dynamic Hydrogels For Use As Reversible 3-D Cell Culture Matrices, Krisitan Stipe

Graduate Student Theses, Dissertations, & Professional Papers

No abstract provided.

Forelimb Position Affects Facultative Bipedal Locomotion In Lizards, Chase T. Kinsey, Lance D. Mcbrayer

Biology: Faculty Publications

Recent work indicates that bipedal posture in lizards is advantageous during obstacle negotiation. However, little is known about how bipedalism occurs beyond a lizard's acceleratory threshold. Furthermore, no study to date has examined the effects of forelimb position on the body center of mass (BCoM) in the context of bipedalism. This study quantified the frequency of bipedalism when sprinting with versus without an obstacle at 0.8 m from the start of a sprint. Forelimb positions were quantified during bipedal running at the start of a sprint and when crossing an obstacle. Two species with contrasting body forms (and thus different …

Parrots And Palms: Analyzing Data To Determine Best Management Strategies And Sustainable Harvest Levels, James P. Gibbs, J. Michelle Cawthorn, Adriana Bravo, Ana L. Porzecanski

Biology: Faculty Publications

This exercise¹ presents a scenario and raw data on a realistic conflict between parrot conservation and palm tree harvest. It requires that students analyze data very comparable to what would be gathered in the field, to: 1) construct a life tables for the palm and parrot, 2) extract vital statistics about both the palm and parrot population from the life tables, 3) estimate maximum sustainable yield for both species, and 4) make a decision about the sustainability of harvest intensity. It illustrates the importance of data analysis skills for conservation.

Rates And Patterns Of Evolution In A Duplicated Genome In The Family Catostomidae, Megann Michelle Schmidt

Honors Program Theses

Whole genome duplication (WGD) is a process in which the entire genome of an organism is duplicated, making redundant genes which are subject to unique evolutionary forces. Various modes of selection create different genetic fates such as retention of ancestral function, development of new function, or loss of function. Because of these differing fates, WGD is hypothesized to be a major driving force behind diversification. In this project, DNA sequences from fish species in the family Catostomidae were examined to observe patterns of evolution following a known WGD. Gene trees were generated for 179 loci to determine the amount of …

Prebiotic Potential Of Aerosols, Emma Rae Shipley

Honors Program Theses

A triple quadrupole gas chromatograpy mass spectrometer (GC/MS/QQQ) was used to determine prebiotic molecules of interest in plasma and photochemical aerosols. Glycolic acid was further studied using isotopically doped gases. Plasma and photochemical aerosol analogs were shown to have nucleobases and a few amino acids. Each type of aerosol was also the source of glycolic acid, a precursor to glycine. Using ¹⁸O doped CO, it was determined that contamination was not a source of oxygen in the samples. Using different combinations of ¹³C doped gases in 1:1 combinations of CO and CH₄, it was determined that …

New Insights Into The "Manna From Heaven" Hypothesis, Clare Laubenthal

Honors Program Theses

Titan’s atmosphere is unique in that its atmospheric chemistry is thought to be similar to that of the Earth’s atmosphere during the Archean Era, when bacterial life dominated the Earth¹. Tholins form as a result of the radiation of organic gases by ultraviolet light. These molecules are considered alike to the prebiotic hazes that formed in the atmosphere of Earth during the Archean Era and which allowed for the eventual development of microbial life² . This study investigated whether Earth soil bacteria can grow, using laboratory created tholin analogs, or aerosols, as a nutrient source. This study …

Morphological, Genetic And Biochemical Characterization Of The Anti-Malarial Herb, Artemisia Annua Germplasm Collection At West Virginia University, Delini K. Samarasinghe

Graduate Theses, Dissertations, and Problem Reports (ETD)

Malaria is one of the deadliest diseases in human history. Nearly half of the world’s population, is at the risk in 106 countries. Only in 2016, this disease killed about 445,000 people, 72% of them being children under age five. It also accounts for US $12 billion dollars of direct costs in Africa alone. Five different species of Plasmodium cause malaria but P. falciparum is the most detrimental one, causing 50% of all malaria cases and is considered as the deadliest parasite in humans. Artemisinin (ART), a 15 C sesquiterpenoid is currently the only precursor to the most effective anti-malarial …

Manipulation Of Genes Involved In Secondary Cell Wall Development During Wood Formation In Poplar, Kavitha Satish Kumar

Dissertations, Master's Theses and Master's Reports

Lignins are second most abundant components of vascular plant cell walls. They provide plants with structural rigidity and are polymers of monolignols. Lignin polymerization is catalyzed by peroxidases and/or laccases. These enzymes are suggested to share functional overlap and mechanism by which they coordinate this process is not clearly understood. There are about 100 peroxidases and 50 laccase genes known in poplar genome out of which some stem differentiating xylem-specific (SDX) enzymes were selected for our study. The main objective was to genetically manipulate genes expressed in the SDX region in the cell wall to see the effects on lignin …

Quantitative Genetics Of Populus, Roba Bdeir

Dissertations, Master's Theses and Master's Reports

Evidence for bark, stem and stomatal density adaptation to different climates in the model species Populus is seen in both the natural population as well as in the greenhouse, but the genetic basis of these adaptation remains poorly understood. The present thesis investigates bark texture, bark thickness, diameter and stomatal density variations among Populus population using two quantitative genetics methods to attempt understand the genetic system controlling inheritance of these traits and to associate them with respective genes. The first approach aimed at detecting quantitative trait loci (QTL) associated with all phenotypic traits in an interspecific hybrid pedigree (Populus …

Assembly And Trafficking Of The Cystic Fibrosis Transmembrane Conductance Regulator And Associated Proteins, Zhihui Zhang

Theses and Dissertations--Chemistry

Cystic Fibrosis (CF) is an autosomal recessive genetic disease that leads to severe malfunction in many organs, but particularly the lungs. The primary cause of this malfunction is the decrease of the airway surface liquid layer on the lung epithelium. The lack of hydration leads to mucus build up on the epithelial lining, leading to blockage of airways. The underlying cause of CF is the dysfunction of the cystic fibrosis transmembrane conductance regulator (CFTR), which results from mutations in the protein. Almost 90% of CF patients are caused by the deletion of the phenylalanine at position 508 of CFTR, which …

Evaluation Of Ispe For Inhibitor Design In The Non-Mevalonate Pathway, Kataryzna Barbara Hoerchler

Graduate Research Theses & Dissertations

There is an urgent need to discover new antibiotics to combat the emergence of drug resistant Novel antibiotics that target unique pathways different from existing therapies are promising targets. The non-mevalonate pathway (MEP), which was discovered in the 1990’s, is essential for most bacteria, plants and apicomplexan parasites. Inhibition of the non-mevalonate is an attractive pharmaceutical target, since it is not present in mammals. Many compounds have surfaced as potential inhibitors, but none have made it to market. This thesis investigates the fourth step in the MEP pathway involving the enzyme 4-diphosphocytidyl-2-C-methyl-D-erythritol kinase (IspE) from Escherichia coli (Ec), Burkholderia thailandensis …

Understanding Carbohydrate Recognition Mechanisms In Non-Catalytic Proteins Through Molecular Simulations, Abhishek A. Kognole

Theses and Dissertations--Chemical and Materials Engineering

Non-catalytic protein-carbohydrate interactions are an essential element of various biological events. This dissertation presents the work on understanding carbohydrate recognition mechanisms and their physical significance in two groups of non-catalytic proteins, also called lectins, which play key roles in major applications such as cellulosic biofuel production and drug delivery pathways. A computational approach using molecular modeling, molecular dynamic simulations and free energy calculations was used to study molecular-level protein-carbohydrate and protein-protein interactions. Various microorganisms like bacteria and fungi secret multi-modular enzymes to deconstruct cellulosic biomass into fermentable sugars. The carbohydrate binding modules (CBM) are non-catalytic domains of such enzymes that …

Protein Engineering In The Study Of Protein Labeling And Degradation, Xinyi Zhang

Theses and Dissertations--Chemistry

Proteins are large macromolecules that play important roles in nature. With the development of modern molecular biology techniques, protein engineering has emerged as a useful tool and found many applications in areas ranging from food industry, environmental protection, to medical and life science. Biomimetic membrane incorporates biological elements, such as proteins, to form membranes that mimic the high specificity and conductance of natural biological membranes. For any application involving the usage of proteins, the first barrier is always the production of proteins with sufficient stability, and the incorporation of proteins into the artificial matrix. This thesis contains two major parts, …

Applications Of Cell-Derived Vesicles: From Single Molecule Studies To Drug Delivery, Faruk H. Moonschi

Theses and Dissertations--Chemistry

Single molecule studies can provide information of biological molecules which otherwise is lost in ensemble studies. A wide variety of fluorescence-based techniques are utilized for single molecule studies. While these tools have been widely applied for imaging soluble proteins, single molecule studies of transmembrane proteins are much more complicated. A primary reason for this is that, unlike membrane proteins, soluble proteins can be easily isolated from the cellular environment. One approach to isolate membrane proteins into single molecule level involves a very low label expression of the protein in cells. However, cells generate background fluorescence leading to a very low …

Protein Suppression Of Flavin Semiquinone As A Mechanistically Important Control Of Reactivity: A Study Comparing Flavoenzymes Which Differ In Redox Properties, Substrates, And Ability To Bifurcate Electrons, John Patrick Hoben

Theses and Dissertations--Chemistry

A growing number of flavoprotein systems have been observed to bifurcate pairs of electrons. Flavin-based electron bifurcation (FBEB) results in products with greater reducing power than that of the reactants with less reducing power. Highly reducing electrons at low reduction midpoint potential are required for life processes of both aerobic and anaerobic metabolic processes. For electron bifurcation to function, the semiquinone (SQ) redox intermediate needs to be destabilized in the protein to suppress its ability to trap electrons. This dissertation examines SQ suppression across a number of flavin systems for the purpose of better understanding the nature of SQ suppression …

The Rtfa Gene Regulates Plant And Animal Pathogenesis And Secondary Metabolism In Aspergillus Flavus, Jessica Michelle Lohmar

Graduate Research Theses & Dissertations

Aspergillus flavus is an opportunistic fungal plant and human pathogen and producer of mycotoxins including aflatoxin B1 (AFB1). As part of our ongoing studies to elucidate biological functions of the A. flavus rtfA gene, we examined its role in pathogenicity of both plant and animal model systems. rtfA encodes a putative RNA-Pol II transcription elongation factor, previously characterized in Saccharomycese cerevisiae, Aspergillus nidulans, Aspergillus fumigatus, where it was shown to regulate several important cellular processes, including morphogenesis, secondary metabolism. In addition, an initial study in A. flavus indicated that rtfA also influences development and production of AFB1, however its effect …