Biochemistry, Biophysics, and Structural Biology Commons^™

Sex And Heterochromatin: An Investigation Of Sexual Dimorphism In Drosophila Melanogaster, Manasi S. Apte

Wayne State University Dissertations

Over 30% of Drosophila genome is assembled into heterochromatin. Heterochromatin is relatively gene poor, transcriptionally less active and remains condensed during interphase. Previous studies established that roX RNA and some of the Male Specific Lethal (MSL) proteins, all components of the dosage compensation complex, are required for full expression of autosomal heterochromatic genes in male flies but not in females. This was surprising since heterochromatin is generally not thought to be sexually dimorphic. The genetic basis for the regulation of sex-specific heterochromatin was completely unknown.

To determine if roX RNAs localize directly at the heterochromatic regions that they regulate, I …

Characterization Of Initial Iron Binding Location And The Structure/Iron Binding Site On S.Cerevisiae Isu And On D.Melanogaster Frataxin, Andria V. Rodrigues

Wayne State University Dissertations

Iron-induced free radical damage has been implicated in the pathology of diseases of iron overload such as Friedreich's Ataxia, a genetic disorder characterized by an accumulation of iron in actively metabolizing tissues ultimately leading to cardio- and neuro- degeneration and cell death. It is caused by an inability to synthesize the mitochondrial protein, frataxin. Frataxin has been shown by numerous groups to be a part of the iron-sulfur cluster (ISC) multicomplex, where it functions in the capacity of a potential iron provider and an allosteric modulator of both the cysteine desulfurase and scaffold protein ISU. My research has been focused …

Characterization Of Prolylcarboxypeptidase Expression Pattern In Rat Cardiomyocytes In Nutrition Overload Conditions, Tahmineh Tabrizian

Electronic Theses and Dissertations

Prolylcarboxypeptidase (PRCP) is a serine protease that cleaves the last amino acid at the carboxy-terminus of peptides with a penultimate proline such as angiotensin II (Ang II), angiotensin III (Ang III), prekallikrein (PK) and α-melanocyte-stimulating-hormone (1-13) (α-MSH1-13). By inactivating Ang II and Ang III, PRCP promotes vasodilation and insulin sensitivity. As well by activating PK, PRCP increases nitric oxide (NO) generation and vasorelaxation through bradykinin (BK) liberation from high molecular weight kininogen (HK). PK is activated to kallikrein by PRCP, implicating a role for PRCP in the coagulation pathway. The resultant kallikrein will activate FXII which in a reciprocal manner …

The Role Of Af9 And Af9-Mediated Protein Interactions In Hematopoiesis And Leukemogenesis, Alyson Anne Lokken

Dissertations

The AF9 protein is one of the most common chromosomal translocation partners of the MLL gene in MLL leukemia. Wild-type AF9 is a member of the pTEFb transcription elongation complex, and interacts with gene regulatory proteins such as AF4/AF5q31, DOT1L, Pc3/CBX8 and BCoR. These interactions are retained in the oncogenic MLL-AF9 fusion protein, and may be required for leukemic transformation.

Using bone marrow progenitor cells isolated from conditional Af9 knockout mice, we examined in vitro differentiation of hematopoietic progenitor cells to the erythroid, myeloid and megakaryocytic lineages in the presence or absence of Af9. Based on previously published studies, we …

Structure And Dynamics Of The Hiv-1 Frameshift Element Rna, Kathryn Mouzakis

Chemistry and Biochemistry Faculty Works

The HIV-1 ribosomal frameshift element is highly structured, regulates translation of all virally encoded enzymes, and is a promising therapeutic target. The prior model for this motif contains two helices separated by a three-nucleotide bulge. Modifications to this model were suggested by SHAPE chemical probing of an entire HIV-1 RNA genome. Novel features of the SHAPE-directed model include alternate helical conformations and a larger, more complex structure. These structural elements also support the presence of a secondary frameshift site within the frameshift domain. Here, we use oligonucleotide-directed structure perturbation, probing in the presence of formamide, and in-virion experiments to examine …

Neuropilin In The Vascular System: Mechanistic Basis Of Angiogenesis, Hou-Fu Guo

Theses and Dissertations--Molecular and Cellular Biochemistry

The vascular system is critical for maintaining homeostasis in all vertebrates. Structural studies of Neuropilin (Nrp), an essential angiogenic receptor, have defined its role in regulating angiogenesis, the formation of new vessels from the existing vasculature. Utilizing biochemical and biophysical tools we describe the ability of Nrp to function as a co-receptor for the VEGFR receptor tyrosine kinase. Two families of Nrp-1 ligands, Vascular Endothelial Growth Factor A (VEGF-A) and Semaphorin3F (Sema3F), physically compete for binding to the Nrp-1 b1 domain, and have opposite roles. VEGF-A is a potent pro-angiogenic cytokine while Sema3F is an angiogenesis inhibitor. Using coupled structural …

Characterization Of Jabba, A Ricin-Resistant Mutant Of Leishmania Donovani, Megan Rhea Phillips

Theses and Dissertations--Molecular and Cellular Biochemistry

The abundant cell-surface lipophosphoglycan (LPG) of Leishmania parasites plays a central role throughout the eukaryote’s life cycle. A number of LPG-defective mutants and their complementing genes have been isolated and have proven invaluable in assessing the importance of LPG and related glycoconjugates in parasite virulence. While ricin agglutination selection protocols frequently result in lpg- mutants, one L. donovani variant we isolated, named JABBA, was found to be lpg+. Procyclic (logarithmic) JABBA expresses significant amounts of a large-sized LPG, larger than observed from procyclic wild-type but similar in size to LPG from wild-type from metacyclic (stationary) phase.

Structural analysis of …

Molecular Mechanisms Of Neuropilin-Ligand Binding, Matthew W. Parker

Theses and Dissertations--Molecular and Cellular Biochemistry

Neuropilin (Nrp) is an essential cell surface receptor with dual functionality in the cardiovascular and nervous systems. The first identified Nrp-ligand family was the Semaphorin-3 (Sema3) family of axon repulsion molecules. Subsequently, Nrp was found to serve as a receptor for the vascular endothelial growth factor (VEGF) family of pro-angiogenic cytokines. In addition to its physiological role, VEGF signaling via Nrp directly contributes to cancer stemness, growth, and metastasis. Thus, the Nrp/VEGF signaling axis is a promising anti-cancer therapeutic target. Interestingly, it has recently been shown that Sema3 and VEGF are functionally opposed to one another, with Sema3 possessing potent …

Leptin Resistance Induced Obesity And Diabetes Promote Neuropathological Changes In The Aging Brain, Thomas Platt

Theses and Dissertations--Molecular and Cellular Biochemistry

The aging brain is prone to the development of pathology and dementia. With a rapidly growing elderly population diagnoses of neurodegenerative diseases, such as Alzheimer’s disease (AD), frontotemporal dementia (FTD), and Parkinson’s disease are on the rise. Additionally, diabetes and obesity are linked to an increased risk of dementia. The convergence of this increasingly aged population with the obesity and diabetes epidemic give rise to new concerns regarding the future of prevention and treatment of neurodegenerative diseases. Our lab has previously shown that leptin, an adipokine involved in signaling satiety to the hypothalamus, can modulate the generation of the amyloid …

Group Via Calcium-Independent Phospholipase A2 Regulates Bcl-Xl Protein Levels In Mice Lung, Sang-Jin Nam

Theses and Dissertations

With previous indication of the Group VIA phospholipase A2 (iPLA2β) enzyme regulating ER-stress induced apoptosis in β-cells by regulating the anti-apoptotic protein Bcl-xL via alternative splicing, our lab postulated iPLA2β to be utilizing a similar mechanism to regulate apoptosis in mice lung. Our previous lab work has shown implications of lung function compromise in iPLA2β-/- mice, and we speculated the cause to be due altered lung architecture stemming from the attenuation of apoptosis. The western blot analysis in this study suggested that iPLA2β is involved in the regulation of Bcl-xL, but the mRNA ratios of the splice variants suggested that …

Investigating The Undefined Role Of Subunit Iiiin Cytochrome C Oxidase Functioning Using Dicyclohexylcarbodiimide Chemical Modification; Insight Into Enzyme Structure And Molecular Mechanism, Kelli Nicole Fisher

Browse all Theses and Dissertations

In the cell metabolic cycle, cytochrome c oxidase (COX) is the final electron acceptor of the respiratory chain which reduces molecular oxygen into water. It is bound in the inner mitochondrial membrane and on the plasma membrane of bacterial species. Energy produced through electron transfer is coupled to the pumping of protons against the electrochemical gradient in order to fuel the proton motive force for the synthesis of most of the ATP in the cell. The three mitochondrial encoded subunits of COX, I, II, and III, are conserved across species and the complete function of subunit III remains unknown. Dicyclohexylcarbodiimide …

The Interactions Between Jak/Stat Signaling Ligands In Drosophila Melanogaster, Qian Chen

Theses and Dissertations--Biology

The development of multi-cellular organisms requires extensive cell-cell communication to coordinate cell functions. However, only a handful of signaling pathways have emerged to mediate all the intercellular communications; therefore, each of them is under an array of regulations to achieve signaling specificity and diversity. One such signaling pathway is the Janus Kinase/ Signal Transducer and Activator of Transcription (JAK/STAT) pathway, which is the primary signaling cascade responding to a variety of cytokines and growth factors in mammals and involved in many developmental processes. This signaling pathway is highly conserved between mammals and Drosophila, …

Structural Mechanisms Of Glucan Phosphatase Activity In Starch Metabolism, David A. Meekins

Theses and Dissertations--Molecular and Cellular Biochemistry

Starch is a water-insoluble glucose biopolymer used as an energy cache in plants and is synthesized and degraded in a diurnal cycle. Reversible phosphorylation of starch granules regulates the solubility and, consequentially, the bioavailability of starch glucans to degradative enzymes. Glucan phosphatases release phosphate from starch glucans and their activity is essential to the proper diurnal metabolism of starch. Previously, the structural basis of glucan phosphatase activity was entirely unknown. The work in this dissertation outlines the structural mechanism of activity of two plant glucan phosphatases called Starch EXcess4 (SEX4) and Like Sex Four2 (LSF2). The crystal structures of SEX4 …

Experimental Infection Of Pregnant Goats With Bovine Viral Diarrhea Virus (Bvdv) 1 Or 2, Thomas Passler, Kay P. Riddell, Misty A. Edmondson, Manuel F. Chamorro, John D. Neill, Bruce W. Brodersen, Heather L. Walz, Patricia K. Galik, Yijing Zhang, Paul H. Walz

School of Veterinary and Biomedical Sciences: Faculty Publications

Infections with bovine viral diarrhea virus (BVDV) of the genus pestivirus, family Flaviviridae, are not limited to cattle but occur in various artiodactyls. Persistently infected (PI) cattle are the main source of BVDV. Persistent infections also occur in heterologous hosts such as sheep and deer. BVDV infections of goats commonly result in reproductive disease, but viable PI goats are rare. Using 2 BVDV isolates, previously demonstrated to cause PI cattle and white-tailed deer, this study evaluated the outcome of experimental infection of pregnant goats. Pregnant goats (5 goats/group) were intranasally inoculated with BVDV 1b AU526 (group 1) or BVDV 2 …

Glutaredoxin-2 Is Required To Control Oxidative Phosphorylation In Cardiac Muscle By Mediating Deglutathionylation Reactions, Mary-Ellen Harper, Ryan J. Mailloux, Jian Ying Xuan, Skye Mcbride, Wael Maharsy, Stephanie Thorn, Chet E. Holterman, Christopher R.J. Kennedy, Peter Rippstein, Robert Dekemp, Jean Da Silva, Mona Nemer, Marjorie Lou

School of Veterinary and Biomedical Sciences: Faculty Publications

Glutaredoxin-2 (Grx2) modulates the activity of several mitochondrial proteins in cardiac tissue by catalyzing deglutathionylation reactions. However, it remains uncertain whether Grx2 is required to control mitochondrial ATP output in heart. Here, we report that Grx2 plays a vital role modulating mitochondrial energetics and heart physiology by mediating the deglutathionylation of mitochondrial proteins. Deletion of Grx2 (Grx2−/−) decreased ATP production by complex I-linked substrates to half that in wild type (WT) mitochondria. Decreased respiration was associated with increased complex I glutathionylation diminishing its activity. Tissue glucose uptake was concomitantly increased. Mitochondrial ATP output and complex I activity could be recovered …

Altered Entrainment To The Day/Night Cycle Attenuates The Daily Rise In Circulating Corticosterone In The Mouse, Patricia J. Sollars, Michael J. Weiser, Andrea E. Kudwa, Jayne R. Bramley, Malcolm D. Ogilvie, Robert L. Spencer, Robert J. Handa, Gary E. Pickard

School of Veterinary and Biomedical Sciences: Faculty Publications

The suprachiasmatic nucleus (SCN) is a circadian oscillator entrained to the day/night cycle via input from the retina. Serotonin (5-HT) afferents to the SCN modulate retinal signals via activation of 5-HT_1B receptors, decreasing responsiveness to light. Consequently, 5-HT_1B receptor knockout (KO) mice entrain to the day/night cycle with delayed activity onsets. Since circulating corticosterone levels exhibit a robust daily rhythm peaking around activity onset, we asked whether delayed entrainment of activity onsets affects rhythmic corticosterone secretion. Wheel-running activity and plasma corticosterone were monitored in mice housed under several different lighting regimens. Both duration of the light:dark cycle (T …

Sumoylation Differentially Regulates Sp1 To Control Cell Differentiation, Lili Gong, Wei-Ke Ji, Xiao-Hui Hu, Wen-Feng Hu, Xiang-Cheng Tang, Zhao-Xia Huang, Ling Li, Mugen Liu, Shi-Hua Xiang, Erxi Wu, Zachary Woodward, Yi-Zhi Liu, Quan Dong Nguyen, David Wan-Cheng Li

School of Veterinary and Biomedical Sciences: Faculty Publications

The mammalian small ubiquitin-like modifiers (SUMOs) are actively involved in regulating differentiation of different cell types. However, the functional differences between SUMO isoforms and their mechanisms of action remain largely unknown. Using the ocular lens as a model system, we demonstrate that different SUMOs display distinct functions in regulating differentiation of epithelial cells into fiber cells. During lens differentiation, SUMO1 and SUMO2/3 displayed different expression, localization, and targets, suggesting differential functions. Indeed, overexpression of SUMO2/3, but not SUMO1, inhibited basic (b) FGF-induced cell differentiation. In contrast, knockdown of SUMO1, but not SUMO2/3, also inhibited bFGF action. Mechanistically, specificity protein 1 …

Protective Humoral Immune Response Induced By An Inactivated Porcine Reproductive And Respiratory Syndrome Virus Expressing The Hypo-Glycosylated Glycoprotein 5, Jung-Ah Lee, Byungjoon Kim, Fernando A. Osorio, Asit K. Pattnaik, Nak-Hyung Lee, Sang-Won Lee, Seung-Yong Park, Chang-Seon Song, In-Soo Choi, Joong-Bok Lee

School of Veterinary and Biomedical Sciences: Faculty Publications

Porcine reproductive and respiratory syndrome (PRRS) causes significant economic losses to the swine industry worldwide. Although inactivated and live vaccines are commercially available for the control of PRRS, both types of vaccine have not always proven successful in terms of generating a protective immune response, particularly in the case of inactivated vaccines. In this study, we tested whether an inactivated vaccine could induce a humoral immune response to PRRS during a homologous challenge. Amino acid substitutions were introduced into glycoprotein (GP) 5 of the FL12 strain of the PRRS virus (PRRSV) using site-directed mutagenesis with a pFL12 infectious clone. The …

Light Stimulates The Mouse Adrenal Through A Retinohypothalamic Pathway Independent Of An Effect On The Clock In The Suprachiasmatic Nucleus, Silke Kiessling, Patricia J. Sollars, Gary E. Pickard

School of Veterinary and Biomedical Sciences: Faculty Publications

The brain’s master circadian pacemaker resides within the hypothalamic suprachiasmatic nucleus (SCN). SCN clock neurons are entrained to the day/night cycle via the retinohypothalamic tract and the SCN provides temporal information to the central nervous system and to peripheral organs that function as secondary oscillators. The SCN clock-cell network is thought to be the hypothalamic link between the retina and descending autonomic circuits to peripheral organs such as the adrenal gland, thereby entraining those organs to the day/night cycle. However, there are at least three different routes or mechanisms by which retinal signals transmitted to the hypothalamus may be conveyed …

Moraxella Spp. Isolated From Field Outbreaks Of Infectious Bovine Keratoconjunctivitis: A Retrospective Study Of Case Submissions From 2010 To 2013, John Dustin Loy, Bruce W. Brodersen

School of Veterinary and Biomedical Sciences: Faculty Publications

Infectious bovine keratoconjunctivitis (IBK), also known as pinkeye, is the most costly eye disease of cattle. The principal etiologic agent of IBK is the Gram-negative bacterium Moraxella bovis. However, there have been reports of IBK outbreaks associated with Moraxella bovoculi. A retrospective study of IBK diagnostic cases submitted from July 1, 2010, through October 31, 2013, was conducted. Included in the study were 1,042 Moraxella isolates from 1,538 swabs of lacrimal secretions collected from 282 herds from 30 U.S. states. Moraxella isolates were identified to the species level and were composed of M. bovoculi (701 isolates), M. bovis …

In Situ Detection Of Autoreactive Cd4 T Cells In Brain And Heart Using Major Histocompatibility Complex Class Ii Dextramers, Chandirasegaran Massilamany, Arunakumar Gangaplara, Ting Jia, Christian Elowsky, Qingsheng Li, You Zhou, Jay Reddy

School of Veterinary and Biomedical Sciences: Faculty Publications

This report demonstrates the use of major histocompatibility complex (MHC) class II dextramers for detection of autoreactive CD4 T cells in situ in myelin proteolipid protein (PLP) 139-151-induced experimental autoimmune encephalomyelitis (EAE) in SJL mice and cardiac myosin heavy chain-α (Myhc) 334-352-induced experimental autoimmune myocarditis (EAM) in A/J mice. Two sets of cocktails of dextramer reagents were used, where dextramers+ cells were analyzed by laser scanning confocal microscope (LSCM): EAE, IAs/PLP 139-151 dextramers (specific)/anti- CD4 and IAs/Theiler’s murine encephalomyelitis virus (TMEV) 70-86 dextramers (control)/anti-CD4; and EAM, IAk/Myhc 334-352 dextramers/ anti-CD4 and IAk/bovine ribonuclease (RNase) 43-56 dextramers (control)/anti-CD4. LSCM analysis of …

Generation Of Calves Persistently Infected With Hobi-Like Pestivirus And Comparison Of Methods For Detection Of These Persistent Infections, F. V. Bauermann, S. M. Falkenberg, B. Vander Ley, N. Decaro, Bruce W. Brodersen, A. Harmon, B. Hessman, E. F. Flores, J. F. Ridpath

School of Veterinary and Biomedical Sciences: Faculty Publications

The identification and elimination of persistently infected (PI) cattle are the most effective measures for controlling bovine pestiviruses, including bovine viral diarrhea virus (BVDV) and the emerging HoBi-like viruses. Here, colostrum-deprived calves persistently infected with HoBi-like pestivirus (HoBi-like PI calves) were generated and sampled (serum, buffy coat, and ear notches) on the day of birth (DOB) and weekly for 5 consecutive weeks. The samples were subjected to diagnostic tests for BVDV—two reverse transcriptase PCR (RT-PCR) assays, two commercial real-time RT quantitative PCR (RT-qPCR), two antigen capture enzyme-linked immunosorbent assays (ACE), and immunohistochemistry (IHC)—and to HoBi-like virus-specific RT-PCR and RT-qPCR assays. …

Generation And Screening Of A Comprehensive Mycobacterium Avium Subsp. Paratuberculosis Transposon Mutant Bank, Govardhan Rathnaiah, Elise A. Lamont, N. Beth Harris, Robert J. Fenton, Denise K. Zinniel, Xiaofei Liu, Josh Sotos, Zhengyu Feng, Ayala Livneh-Kol, Nahum Y. Shpigel, Charles J. Czuprynski, Srinand Sreevatsan, Raul G. Barletta

School of Veterinary and Biomedical Sciences: Faculty Publications

Mycobacterium avium subsp. paratuberculosis (MAP) is the etiologic agent of Johne’s Disease in ruminants. This enteritis has significant economic impact and world wide distribution. Vaccination is one of the most cost effective infectious disease control measures. Unfortunately, current vaccines reduce clinical disease and shedding, but are of limited efficacy and do not provide long-term protective immunity. Several strategies have been followed to mine the MAP genome for virulence determinants that could be applied to vaccine and diagnostic assay developent. In this study, a comprehensive mutant bank of 13,536 MAP K-10 Tn5367 mutants (P>95% )was constructed and screened in …

Noninvasive Assessment Of Cardiac Abnormalities In Experimental Autoimmune Myocarditis By Magnetic Resonance Microscopy Imaging In The Mouse, Chandirasegara Massilamany, Vahid Khalilzad-Sharghi, Arunakumar Gangaplara, David Steffen, Shadi F. Othman, Jay Reddy

School of Veterinary and Biomedical Sciences: Faculty Publications

Myocarditis is an inflammation of the myocardium, but only ~10% of those affected show clinical manifestations of the disease. To study the immune events of myocardial injuries, various mouse models of myocarditis have been widely used. This study involved experimental autoimmune myocarditis (EAM) induced with cardiac myosin heavy chain (Myhc)-α 334-352 in A/J mice; the affected animals develop lymphocytic myocarditis but with no apparent clinical signs. In this model, the utility of magnetic resonance microscopy (MRM) as a non-invasive modality to determine the cardiac structural and functional changes in animals immunized with Myhc-α 334-352 is shown. EAM and healthy mice …

Intricacies Of Cardiac Damage In Coxsackievirus B3 Infection: Implications For Therapy, Chandirasegara Massilamany, Arunakumar Gangaplara, Jay Reddy

School of Veterinary and Biomedical Sciences: Faculty Publications

Heart disease is the leading cause of death in humans, and myocarditis is one predominant cause of heart failure in young adults. Patients affected with myocarditis can develop dilated cardiomyopathy (DCM), a common reason for heart transplantation, which to date is the only viable option for combatting DCM. Myocarditis/DCM patients show antibodies to coxsackievirus B (CVB)3 and cardiac antigens, suggesting a role for CVB-mediated autoimmunity in the disease pathogenesis; however, a direct causal link remains to be determined clinically. Experimentally, myocarditis can be induced in susceptible strains of mice using the human isolates of CVB3, and the disease pathogenesis of …

Direct Staining With Major Histocompatibility Complex Class Ii Dextramers Permits Detection Of Antigen- Specific, Autoreactive Cd4 T Cells In Situ, Chandirasegaran Massilamany, Arunakumar Gangaplara, Ting Jia, Christian Elowsky, Guobin Kang, Jean-Jack Riethoven, Qingsheng Li, You Zhou, Jay Reddy

School of Veterinary and Biomedical Sciences: Faculty Publications

We report here the utility of major histocompatibility complex (MHC) class II dextramers for in situ detection of self-reactive CD4 T cells in two target organs, the brain and heart. We optimized the conditions for in situ detection of antigen-specific CD4 T cells using brain sections obtained from SJL mice immunized with myelin proteolipid protein (PLP) 139–151; the sections were costained with IA^s/PLP 139–151 (specific) or Theiler’s murine encephalomyelitis virus (TMEV) 70–86 (control) dextramers and anti-CD4. Analysis of sections by laser scanning confocal microscope revealed detection of cells positive for PLP 139–151 but not for TMEV 70–86 dextramers …

Influence Of Iron And Aeration On Staphylococcus Aureus Growth, Metabolism, And Transcription, Nagender Ledala, Bo Zhang, Javier Seravalli, Robert Powers, Greg Somerville

School of Veterinary and Biomedical Sciences: Faculty Publications

Staphylococcus aureus is a prominent nosocomial pathogen and a major cause of biomaterial-associated infections. The success of S. aureus as a pathogen is due in part to its ability to adapt to stressful environments. As an example, the transition from residing in the nares to residing in the blood or deeper tissues is accompanied by changes in the availability of nutrients and elements such as oxygen and iron. As such, nutrients, oxygen, and iron are important determinants of virulence factor synthesis in S. aureus. In addition to influencing virulence factor synthesis, oxygen and iron are critical cofactors in enzymatic and …

Book Review Of Dane Kennedy, The Last Blank Spaces: Exploring Africa And Australia, Adrian S. Wisnicki

Department of Biochemistry: Faculty Publications

Mid-nineteenth-century British exploration, particularly the stories of the “heroic” individuals who carried out this exploration, remains a topic of worldwide interest, as most recently evidenced by the many events in Britain and Africa celebrating the 2013 bicentenary of David Livingstone’s birth. Dane Kennedy’s intriguing study takes issue with such readings of the historical record by foregrounding an epistemological tension that lies at the heart of nineteenthcentury British exploration discourse and practice. The book examines the collision—as it played out in the exploration of African and Australia—between metropolitan scientific protocols and non-Western quotidian realities. Nineteenth-century explorers, argues Kennedy, left home with …

Protein/Protein Interactions In The Mammalian Heme Degradation Pathway: Heme Oxygenase-2, Cytochrome P450 Reductase, And Biliverdin Reductase, Andrea L. M. Spencer, Ireena Bagai, Donald F. Becker, Erik R. P. Zuiderweg, Stephen W. Ragsdale

Department of Biochemistry: Faculty Publications

Heme oxygenase (HO) catalyzes the rate-limiting step in the O₂- dependent degradation of heme to biliverdin, CO, and iron with electrons delivered from NADPH via cytochrome P450 reductase (CPR). Biliverdin reductase (BVR) then catalyzes conversion of bili­verdin to bilirubin. We describe mutagenesis combined with kinetic, spectroscopic (fluorescence and NMR), surface plasmon resonance, cross-linking, gel filtration, and analytical ultracentrifugation studies aimed at evaluating interactions of HO-2 with CPR and BVR. Based on these results, we propose a model in which HO-2 and CPR form a dynamic ensemble of complex(es) that precede formation of the productive electron transfer complex. The …

Arabidopsis Cuticular Wax Biosynthesis Is Negatively Regulated By The Dewax Gene Encoding An Ap2/Erf-Type Transcription Factor, Young Sam Go, Hyojin Kim, Hae Jin Kim, Mi Chung Suh

Department of Biochemistry: Faculty Publications

The aerial parts of plants are protected from desiccation and other stress by surface cuticular waxes. The total cuticular wax loads and the expression of wax biosynthetic genes are significantly downregulated in Arabidopsis thaliana under dark conditions. We isolated Decrease Wax Biosynthesis (DEWAX), which encodes an AP2/ERF-type transcription factor that is preferentially expressed in the epidermis and induced by darkness. Disruption of DEWAX leads to an increase in total leaf and stem wax loads, and the excess wax phenotype of dewax was restored to wild type levels in complementation lines. Moreover, overexpression of DEWAX resulted in a reduction …