Biochemistry, Biophysics, and Structural Biology Commons^™

Effects Of 5-Hydroxytryptamine 2c Receptor Agonist Mk212 And 2a Receptor Antagonist Mdl100907 On Maternal Behavior In Postpartum Female Rats, Weihai Chen, Qi Zhang, Wenxin Su, Yu Yang, Jing Qiao, Nan Sui, Ming Li

Department of Psychology: Faculty Publications

Maternal behavior in rats is a highly motivated and well-organized social behavior. Given the known roles of serotonin (5-HT) in emotion, motivation, social behavior, and major depression – and its known interaction with dopamine – it is likely that serotonin also plays a crucial role in this behavior. So far, there are surprisingly few studies focusing on 5-HT in maternal behavior, except for maternal aggression. In the present study,we examined the effects of 5-HT_2C receptor agonism and 5-HT_2A receptor antagonism on maternal behavior in postpartum female rats.We hypothesized that activation of 5-HT_2C receptors and blockade of 5-HT …

Arabidopsis Accelerated Cell Death 11, Acd11, Is A Ceramide-1-Phosphate Transfer Protein And Intermediary Regulator Of Phytoceramide Levels, Dhirendra K. Simanshu, Xiuhong Zhai, David Munch, Daniel Hofius, Jennifer E. Markham, Jacek Bielawski, Alicja Bielawska, Lucy Malinina, Julian G. Molotkovsky, John W. Mundy, Dinshaw J. Patel, Rhoderick E. Brown

Department of Biochemistry: Faculty Publications

The accelerated cell death 11 (acd11) mutant of Arabidopsis provides a genetic model for studying immune response activation and localized cellular suicide that halt pathogen spread during infection in plants. Here, we elucidate ACD11 structure and function and show that acd11 disruption dramatically alters the in vivo balance of sphingolipid mediators that regulate eukaryotic-programmed cell death. In acd11 mutants, normally low ceramide-1- phosphate (C1P) levels become elevated, but the relatively abundant cell death inducer phytoceramide rises acutely. ACD11 exhibits selective intermembrane transfer of C1P and phyto-C1P. Crystal structures establish C1P binding via a surface-localized, phosphate headgroup recognition center …

Evidence For Hysteretic Substrate Channeling In The Proline Dehydrogenaseand ∆1-Pyrroline-5-Carboxylate Dehydrogenase Coupled Reaction Of Proline Utilizationa(Puta), Michael A Moxley, Nikhilesh Sanyal, Navasona Krishnan, John J. Tanner, Donald F. Becker

Department of Biochemistry: Faculty Publications

Background: PutA from Escherichia coli is a bifunctional enzyme and transcriptional repressor in proline catabolism.

Results: Steady-state and transient kinetic data revealed a mechanism in which the two enzymatic reactions are coupled by an activation step.

Conclusion: Substrate channeling in PutA exhibits hysteretic behavior.

Significance: This is the first kinetic model of bi-enzyme activity in PutA and reveals a novel mechanism of channeling activation.

Evaluation Of Three Herbicide Resistance Genes For Use In Genetic Transformations And For Potential Crop Protection In Algae Production, Andrew J. Bruggeman, Daniel Kuehler, Donald P. Weeks

Department of Biochemistry: Faculty Publications

Genes conferring resistance to the herbicides glyphosate, oxyfluorfen and norflurazon were developed and tested for use as dominant selectable markers in genetic transformation of Chlamydomonas reinhardtii and as potential tools for the protection of commercial-scale algal production facilities against contamination by organisms sensitive to these broad-spectrum herbicides. A synthetic glyphosate acetyltransferase (GAT) gene, when fitted with a strong Chlamydomonas promoter, conferred a 2.79-fold increase in tolerance to the EPSPS inhibitor, glyphosate, in transgenic cells compared with progenitor WT cells. A mutant Chlamydomonas protoporphyrinogen oxidase (protox, PPO) gene previously shown to produce an enzyme insensitive to PPO-inhibiting herbicides, when genetically engineered, …

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 …

Dens Agenesis And Cervical Vertebral Malformation In A Labrador Retriever Puppy, Elisa Salas, Henry E. Cerny, Seth P. Harris

School of Veterinary and Biomedical Sciences: Faculty Publications

Cervical vertebral malformations can cause acute or progressive pain, paralysis, and potentially death. Herein we present a case report of dens agenesis; cervical vertebral malformations of C1, C2, C6, and C7; subluxation of C1 and C2 and C4 and C5; and associated degenerative myelopathy in a 5-month-old female Labrador Retriever puppy. We additionally review current knowledge regarding pathogenesis and treatment.

Pharmacokinetic And Biodistribution Assessment Of A Near Infrared-Labeled Psma-Specific Small Molecule In Tumor-Bearing Mice, Joy L. Kovar, Lael L. Cheung, Melanie A. Simpson, D. Michael Olive

Department of Biochemistry: Faculty Publications

Prostate cancer is themost frequently diagnosed cancer in men and often requires surgery. Use of near infrared (NIR) technologies to perform image-guided surgery may improve accurate delineation of tumor margins. To facilitate preclinical testing of such outcomes, here we developed and characterized a PSMA-targeted small molecule, YC-27. IRDye 800CW was conjugated to YC-27 or an anti-PSMA antibody used for reference. Human 22Rv1, PC3M-LN4, and/or LNCaP prostate tumor cells were exposed to the labeled compounds. In vivo targeting and clearance properties were determined in tumor-bearing mice. Organs and tumors were excised and imaged to assess probe localization. YC-27 exhibited a dose …

Preliminary Joint X-Ray And Neutron Protein Crystallographic Studies Of Ecdhfr Complexed With Folate And Nadp+, Qun Wan, Audrey Y. Kovalevsky, Mark A. Wilson, Brad C. Bennett, Paul Langan, Chris Dealwis

Department of Biochemistry: Faculty Publications

A crystal of Escherichia coli dihydrofolate reductase (ecDHFR) complexed with folate and NADP⁺ of 4 x 1.3 x 0.7 mm (3.6 mm³) in size was obtained by sequential application of microseeding and macroseeding. A neutron diffraction data set was collected to 2.0 A resolution using the IMAGINE diffractometer at the High Flux Isotope Reactor within Oak Ridge National Laboratory. A 1.6 A resolution X-ray data set was also collected from a smaller crystal at room temperature. The neutron and X-ray data were used together for joint refinement of the ecDHFR–folate–NADP⁺ ternary-complex structure in order to examine …

Ycf1-Mediated Cadmium Resistance In Yeast Is Dependent On Copper Metabolism And Antioxidant Enzymes, Wenzhong Wei, Nathan Smith, Xiaobin Wu, Heejeong Kim, Javier Seravalli, Oleh Khalimonchuk, Jaekwon Lee

Department of Biochemistry: Faculty Publications

Aims: Acquisition and detoxification of metal ions are vital biological processes. Given the requirement of metallochaperones in cellular copper distribution and metallation of cuproproteins, this study investigates whether the metallochaperones also deliver metal ions for transporters functioning in metal detoxification. Results: Resistance to excess cadmium and copper of the yeast Saccharomyces cerevisiae, which is conferred by PCA1 and CaCRP1 metal efflux P-type ATPases, respectively, does not rely on known metallochaperones, Atx1p, Ccs1p, and Cox17p. Copper deficiency induced by the expression of CaCRP1 encoding a copper exporter occurs in the absence of Atx1p. Intriguingly, CCS1 encoding the copper chaperone for superoxide …

Novel Gammaherpesvirus Functions 1 Encoded By Bovine Herpesvirus (Bovine Lymphotropic Virus), J. Jia, G. Delhon, E. R. Tulman, D. G. Diel, Fernando A. Osorio, X. Wen, G. F. Kutish, D. L. Rock

School of Veterinary and Biomedical Sciences: Faculty Publications

The genus Macavirus of the subfamily Gammaherpesvirinae includes viruses that infect lymphoid cells of domestic and wild ruminants and swine, causing asymptomatic latent infections in reservoir hosts. Here, we describe the genome of bovine herpesvirus 6 (BoHV-6), a

macavirus ubiquitous in healthy cattle populations. The BoHV-6 genome exhibited architecture conserved in macaviruses, including a repetitive H-DNA region and unique, 141 kilobase pair L

DNA region predicted to encode 77 genes. BoHV-6 encoded in variable genomic regions a novel complement of genes relative to other characterized macaviruses, likely contributing to distinctive aspects of BoHV-6 infection biology and host range. Most notably, …

Comparative Analyses Of Three Chlorella Species In Response To Light And Sugar Reveal Distinctive Lipid Accumulation Patterns In The Microalga C. Sorokiniana, Julian N. Rosenberg, Naoko Kobayashi, Austin Barnes, Eric A. Noel, Michael J. Betenbaugh, George A. Oyler

Department of Biochemistry: Faculty Publications

While photosynthetic microalgae, such as Chlorella, serve as feedstocks for nutritional oils and biofuels, heterotrophic cultivation can augment growth rates, support high cell densities, and increase triacylglycerol (TAG) lipid content. However, these species differ significantly in their photoautotrophic and heterotrophic characteristics. In this study, the phylogeny of thirty Chlorella strains was determined in order to inform bioprospecting efforts and detailed physiological assessment of three species. The growth kinetics and lipid biochemistry of C. protothecoides UTEX 411, C. vulgaris UTEX 265, and C. sorokiniana UTEX 1230 were quantified during photoautotrophy in Bold’s basal medium (BBM) and heterotrophy in BBM supplemented …

Evaluating The Clinical And Physiological Effects Of Long Term Ultraviolet B Radiation On Guinea Pigs (Cavia Porcellus), Megan K. Watson, Adam W. Stern, Amber L. Labelle, Stephen Joslyn, Timonthy M. Fan, Katie Leister, Micah Kohles, Kemba Marshall, Mark A. Mitchell

School of Veterinary and Biomedical Sciences: Faculty Publications

Vitamin D is an important hormone in vertebrates. Most animals acquire this hormone through their diet, secondary to exposure to ultraviolet B (UVB) radiation, or a combination thereof. The objectives for this research were to evaluate the clinical and physiologic effects of artificial UVB light supplementation on guinea pigs (Cavia porcellus) and to evaluate the long-term safety of artificial UVB light supplementation over the course of six months. Twelve juvenile acromelanic Hartley guinea pigs were randomly assigned to one of two treatment groups: Group A was exposed to 12 hours of artificial UVB radiation daily and Group B …

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 …

Stress Adaptation In A Pathogenic Fungus, Alistair J. P. Brown, Susan Budge, Despoina Kaloriti, Anna Tillmann, Mette D. Jacobsen, Zhikang Yin, Iuliana V. Ene, Iryna Bohovych, Doblin Sandai, Stavroula Kastora, Joanna Potrykus, Elizabeth R. Ballou, Delma S. Childers, Shahida Shahana, Michelle D. Leach

Department of Biochemistry: Faculty Publications

Candida albicans is a major fungal pathogen of humans. This yeast is carried by many individuals as a harmless commensal, but when immune defences are perturbed it causes mucosal infections (thrush). Additionally, when the immune system becomes severely compromised, C. albicans often causes life-threatening systemic infections. A battery of virulence factors and fitness attributes promote the pathogenicity of C. albicans. Fitness attributes include robust responses to local environmental stresses, the inactivation of which attenuates virulence. Stress signalling pathways in C. albicans include evolutionarily conserved modules. However, there has been rewiring of some stress regulatory circuitry such that the roles of …