Biochemistry, Biophysics, and Structural Biology Commons^™

Single-Molecule Unbinding Forces Between The Polysaccharide Hyaluronan And Its Binding Proteins, Fouzia Bano, Markku I. Tammi, David W. Kang, Edward N. Harris, Ralf P. Richter

Department of Biochemistry: Faculty Publications

The extracellular polysaccharide hyaluronan (HA) is ubiquitous in all vertebrate tissues, where its various functions are encoded in the supramolecular complexes and matrices that it forms with HA-binding proteins (hyaladherins). In tissues, these supramolecular architectures are frequently subjected to mechanical stress, yet how this affects the intermolecular bonding is largely unknown. Here, we used a recently developed single-molecule force spectroscopy platform to analyze and compare the mechanical strength of bonds between HA and a panel of hyaladherins from the Link module superfamily, namely the complex of the proteoglycan aggrecan and cartilage link protein, the proteoglycan versican, the inflammation-associated protein TSG-6, …

Endosomal Escape Of Antisense Oligonucleotides Internalized By Stabilin Receptors Is Regulated By Rab5c And Eea1 During Endosomal Maturation, Colton M. Miller, W. Brad Wan, Punit P. Seth, Edward N. Harris

Department of Biochemistry: Faculty Publications

Second-generation (Gen 2) Antisense oligonucleotides (ASOs) show increased nuclease stability and affinity for their RNA targets, which has translated to improved potency and therapeutic index in the clinic. Gen 2 ASOs are typically modified using the phosphorothioate (PS) backbone modification, which enhances ASO interactions with plasma, cell surface, and intracellular proteins. This facilitates ASO distribution to peripheral tissues and also promotes cellular uptake after injection into animals. Previous work identified that Stabilin receptors specifically internalize PS-ASOs in the sinusoidal endothelial cells of the liver and the spleen. By modulating expression of specific proteins involved in the trafficking and maturation of …

Purification Of Hepatocytes And Sinusoidal Endothelial Cells From Mouse Liver Perfusion, Fatima Cabral, Colton M. Miller, Katrina M. Kudrna, Blake E. Hass, Jocelyn G. Daubendiek, Brianna M. Kellar, Edward N. Harris

Department of Biochemistry: Faculty Publications

This protocol demonstrates a method for obtaining high yield and viability for mouse hepatocytes and sinusoidal endothelial cells (SECs) suitable for culturing or for obtaining cell lysates. In this protocol, the portal vein is used as the site for catheterization, rather than the vena cava, as this limits contamination of other possible cell types in the final liver preparation. No special instrumentation is required throughout the procedure. A water bath is used as a source of heat to maintain the temperature of all the buffers and solutions. A standard peristaltic pump is used to drive the fluid, and a refrigerated …

A Tlr/Akt/Foxo3 Immune Tolerance–Like Pathway Disrupts The Repair Capacity Of Oligodendrocyte Progenitors, Taasin Srivastava, Parham Diba, Justin M. Dean, Fatima Banine, Daniel Shaver, Matthew Hagen, Xi Gong, Weiping Su, Ben Emery, Daniel L. Marks, Edward N. Harris, Bruce Baggentoss, Paul H. Weigel, Larry S. Sherman, Stephen A. Back

Department of Biochemistry: Faculty Publications

Cerebral white matter injury (WMI) persistently disrupts myelin regeneration by oligodendrocyte progenitor cells (OPCs). We identified a specific bioactive hyaluronan fragment (bHAf) that downregulates myelin gene expression and chronically blocks OPC maturation and myelination via a tolerance-like mechanism that dysregulates pro-myelination signaling via AKT. Desensitization of AKT occurs via TLR4 but not TLR2 or CD44. OPC differentiation was selectively blocked by bHAf in a maturation-dependent fashion at the late OPC (preOL) stage by a noncanonical TLR4/TRIF pathway that induced persistent activation of the FoxO3 transcription factor downstream of AKT. Activated FoxO3 selectively localized to oligodendrocyte lineage cells in white matter …

3-O Sulfation Of Heparin Leads To Hepatotropism And Longer Circulatory Half-Life, Colton M. Miller, Yongmei Xu, Katrina M. Kudrna, Blake E. Hass, Brianna M. Kellar, Andrew W. Egger, Jian Liu, Edward N. Harris

Department of Biochemistry: Faculty Publications

Introduction: Heparins are common blood anticoagulants that are critical for many surgical and biomedical procedures used in modern medicine. In contrast to natural heparin derived from porcine gut mucosa, synthetic heparins are homogenous by mass, polymer length, and chemistry.

Materials & methods: Stable cell lines expressing the human and mouse Stabilin receptors were used to evaluate endocytosis of natural and synthetic heparin. We chemoenzymatically produced synthetic heparin consisting of 12 sugars (dodecamers) containing 14 sulfate groups resulting in a non-3-O sulfated structure (n12mer). Half of the n12mer was modified with a 3-O sulfate on a single GlcNS sugar producing the …

Characterization Of A Recurrent Missense Mutation In The Forkhead Dna-Binding Domain Of Foxp1, Tyler B. Johnson, Keegan Mechels, Ruth Ellen Anderson, Jacob T. Cain, David A. Sturdevant, Stephen Braddock, Hailey Pinz, Mark A. Wilson, Megan Landsverk, Kyle J. Roux, Jill M. Weimer

Department of Biochemistry: Faculty Publications

Haploinsufficiency of Forkhead box protein P1 (FOXP1), a highly conserved transcription factor, leads to developmental delay, intellectual disability, autism spectrum disorder, speech delay, and dysmorphic features. Most of the reported FOXP1 mutations occur on the C-terminus of the protein and cluster around to the forkhead domain. All reported FOXP1 pathogenic variants result in abnormal cellular localization and loss of transcriptional repression activity of the protein product. Here we present three patients with the same FOXP1 mutation, c.1574G>A (p.R525Q), that results in the characteristic loss of transcription repression activity. This mutation, however, represents the first reported FOXP1 mutation that does …

Editorial: Structure And Function Of Chloroplasts, Rebecca L. Roston, Juliette Jouhet, Fei Yu, Hongbo Gao

Department of Biochemistry: Faculty Publications

The primary energy resource of life on earth is the sun, whose energy is captured in the form of usable carbons by a process called photosynthesis. Photosynthesis occurs within a cellular organelle adapted to that purpose, called the chloroplast. Chloroplasts are unique metabolic and sensory organelles restricted to plants, algae, and a few protists. In this special topic, we aimed to gather new research, hypotheses, and reviews that would help us to better understand the important role of chloroplasts in all photosynthetic organisms. We were fortunate enough to have submissions from many talented chloroplast researchers. This topic contains a total …

Identification Of Genes Encoding Enzymes Catalyzing The Early Steps Of Carrot Polyacetylene Biosynthesis, Lucas Busta, Won Cheol Yim, Evan William Labrant, Peng Wang, Lindsey Grimes, Kiah Malyszka, John C. Cushman, Patricia Santos, Dylan K. Kosma, Edgar B. Cahoon

Department of Biochemistry: Faculty Publications

Polyacetylenic lipids accumulate in various Apiaceae species after pathogen attack, suggesting that these compounds are naturally occurring pesticides and potentially valuable resources for crop improvement. These compounds also promote human health and slow tumor growth. Even though polyacetylenic lipids were discovered decades ago, the biosynthetic pathway underlying their production is largely unknown. To begin filling this gap and ultimately enable polyacetylene engineering, we studied polyacetylenes and their biosynthesis in the major Apiaceae crop carrot (Daucus carota subsp. sativus). Using gas chromatography and mass spectrometry, we identified three known polyacetylenes and assigned provisional structures to two novel polyacetylenes. We …

Role Of Selenof As A Gatekeeper Of Secreted Disulfide-Rich Glycoproteins, Sun Hee Yim, Robert A. Everley, Frank A. Schildberg, Sang-Goo Lee, Andrea Orsi, Zachary R. Barbati, Kutay Karatepe, Dmitry E. Fomenko, Petra A. Tsuji, Hongbo R. Luo, Steven P. Gygi, Roberto Sitia, Arlene H. Sharpe, Dolph L. Hatfield, Vadim N. Gladyshev

Department of Biochemistry: Faculty Publications

Selenof (15-kDa selenoprotein; Sep15) is an endoplasmic reticulum (ER)-resident thioredoxin-like oxidoreductase that occurs in a complex with UDPglucose: glycoprotein glucosyltransferase. We found that Selenof deficiency in mice leads to elevated levels of non-functional circulating plasma immunoglobulins and increased secretion of IgM during in vitro splenic B cell differentiation. However, Selenof knockout animals show neither enhanced bacterial killing capacity nor antigen-induced systemic IgM activity, suggesting that excess immunoglobulins are not functional. In addition, ER-to-Golgi transport of a target glycoprotein was delayed in Selenof knockout embryonic fibroblasts, and proteomic analyses revealed that Selenof deficiency is primarily associated with antigen presentation and ER-to-Golgi …

Visualizing The Invisible: A Guide To Designing, Printing, And Incorporating Dynamic 3d Molecular Models To Teach Structure–Function Relationships, Michelle E. Howell, Karin V. Van Dijk, Christine S. Booth, Tomáš Helikar, Brian A. Couch, Rebecca Roston

Department of Biochemistry: Faculty Publications

Understanding the intricate relationship between macromolecular structure and function represents a central goal of undergraduate biology education (1–3). In teaching complex three-dimensional (3D) concepts, instructors typically depend on static two-dimensional (2D) textbook images or computer-based visualization software, which can lead to unintended misconceptions (4–6). While chemical and molecular kits exist, these models cannot handle the size and detail of macromolecules. Consequently, students may graduate in the life sciences without understanding how structure underlies function or acquiring skills to translate between 2D and 3D molecular models (5, 7).

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 …

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

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 …

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, …

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 …

Study Of The Mechanism Of Action For Ru(Ii) Polypyridyl Complexes As Potential Anticancer Agents, Yang Sun

Theses and Dissertations--Chemistry

Application of chemotherapeutic agents in current cancer treatment has been limited by adverse effects as poor selectivity results in systemic toxicity; most chemotherapy approaches also experience inherited or acquired drug resistance which lead to reduced treatment outcome. Research efforts have focused on the discovery of novel chemotherapies that overcome the limitations mentioned above. Ru(II) polypyridyl complexes with anti-cancer properties have been extensively studied as traditional cytotoxic agents and photodynamic therapy agents due to their photophysical and photochemical characteristics.

Most research has focused on the design of Ru(II) polypyridyl complexes that have affinities to nucleic acids as inspired by the classic …

The Distinction Of The Interactions Between The Transmembrane Domains Of Basigin Gene Products And Monocarboxylate Transporters, Joseph D. Fong

UNF Graduate Theses and Dissertations

Although it was once thought that neurons solely rely on glucose as a substrate for cellular energy production, it is now known that small monocarboxylate molecules, like pyruvate, lactate, and ketone bodies, are also utilized. Monocarboxylates are transported across plasma membranes via facilitated diffusion using a family of transport proteins known as monocarboxylate transporters (MCTs). Four MCTs (MCT1, MCT2, MCT3, and MCT4) are expressed within neural tissues. Expression of the MCTs has been tied to co-expression of a cell adhesion molecule belonging to the Basigin subset of the immunoglobulin superfamily (IgSF). Basigin gene products are known to interact with MCT1 …

Crystal Structure Of (2-{[(8-Aminona­Phthalen-1-Yl)Imino]­Meth­Yl}-4,6-Di-Tert-Butyl­Phenolato-Κ3n,N′,O)Bromido­Nickel(Ii), Patrick O’Brien, Matthias Zeller, Wei-Tsung Less

Chemistry: Faculty Publications and Other Works

The title compound, [NiBr(C25H29N2O)], contains an NiII atom with a slightly distorted square-planar coordination environment defined by one O and two N atoms from the 2-{[(8-aminonaphthalen-1-yl)imino]methyl}-4,6-di-tert-butylphenolate ligand and a bromide anion. The Ni—O and Ni—N bond lengths are slightly longer than those observed in the phenyl backbone counterpart, which can be attributed to the larger steric hindrance of the naphthyl group in the structure of the title compound. The molecule as a whole is substantially distorted, with both the planar naphthalene-1,8-diamine and imino–methyl– phenolate substitutents rotated against the NiN2OBr plane by 38.92 (7) and 37.22 (8), respectively, giving the molecule …

Identification Of Genes And Metabolites Involved In Durian Durio Zibethinus Fruit Ripening, Pinnapat Pinsorn

Chulalongkorn University Theses and Dissertations (Chula ETD)

Durian (Durio zibethinus M.), a major economic fruit, actively produces infamous sulfur-containing compounds during ripening. However, sulfur metabolism which is important in this fruit is rarely investigated. In this study, the integration of metabolomics using CE-TOF/MS and transcriptomics using de novo RNA-seq assembly was performed to reveal metabolic changes involved in sulfur metabolism and chemical composition related to fruit quality. During ripening, the expression level of genes involved in sulfur metabolism is concurred with the reduced sulfate ion content in placenta and the up-accumulation of sulfur metabolism-related metabolites in pulps. It is noteworthy that durian pulps highly accumulate γ-glutamylcysteine (γ-EC) …

Development Of Simple Devices For Point-Of-Care Screening Of Bacterial Infection And Inflammatory Markers, Julaluk Noiphung

Chulalongkorn University Theses and Dissertations (Chula ETD)

A paper-based analytical devices (PADs) provides a great benefit in medical diagnostics, especially in the developing world. The first part of this dissertation describes the effect of sample viscosity on PADs for the measurement of pH and nitrite concentration in human saliva. Preliminary study found that viscosity had a significant effect on the calibration curve of nitrite and a consistent curve could be generated after added washing buffer. Nitrite measurement in artificial saliva with viscosity 1.87-5.10 mPa-s was tested on the proposed device and also showed a good correlation with the standard spectrophotometry method (p=0.8484, paired sample t-test, n=20). Moreover, …