Veterinary Pathology and Pathobiology Commons^™

Cellular Poly(C) Binding Proteins 1 And 2 Interact With Porcine Reproductive And Respiratory Syndrome Virus Nonstructural Protein 1Β And Support Viral Replication, Lalit Beura, Phat X. Dinh, Fernando A. Osorio, Asit K. Pattnaik

School of Veterinary and Biomedical Sciences: Faculty Publications

Porcine reproductive and respiratory syndrome virus (PRRSV) infection of swine results in substantial economic losses to the swine industry worldwide. Identification of cellular factors involved in PRRSV life cycle not only will enable a better understanding of virus biology but also has the potential for the development of antiviral therapeutics. The PRRSV nonstructural protein 1 (nsp1) has been shown to be involved in at least two important functions in the infected hosts: (i) mediation of viral subgenomic (sg) mRNA transcription and (ii) suppression of the host’s innate immune response mechanisms. To further our understanding of the role of the viral …

Genome Of Mycoplasma Haemofelis, Unraveling Its Strategies For Survival And Persistence, Andrea P. Santos, Ana Ms Guimaraes, Naila C. Do Nascimento, Phillip J. Sanmiguel, Samuel W. Martin, Joanne Messick

Department of Comparative Pathobiology Faculty Publications

Mycoplasma haemofelis is a mycoplasmal pathogen (hemoplasma) that attaches to the host’s erythrocytes. Distributed worldwide, it has a significant impact on the health of cats causing acute disease and, despite treatment, establishing chronic infection. It might also have a role as a zoonotic agent, especially in immunocompromised patients. Whole genome sequencing and analyses of M. haemofelis strain Ohio2 was undertaken as a step toward understanding its survival and persistence. Metabolic pathways are reduced, relying on the host to supply many of the nutrients and metabolites needed for survival. M. haemofelis must import glucose for ATP generation and ribose derivates for …

Antagonistic Effects Of Cellular Poly(C) Binding Proteins On Vesicular Stomatitis Virus Gene Expression, Phat X. Dinh, Lalit Beura, Debasis Panda, Anshuman Das, Asit K. Pattnaik

School of Veterinary and Biomedical Sciences: Faculty Publications

Immunoprecipitation and subsequent mass spectrometry analysis of the cellular proteins from cells expressing the vesicular stomatitis virus (VSV) P protein identified the poly(C) binding protein 2 (PCBP2) as one of the P protein-interacting proteins. To investigate the role of PCBP2 in the viral life cycle, we examined the effects of depletion or overexpression of this protein on VSV growth. Small interfering RNA-mediated silencing of PCBP2 promoted VSV replication. Conversely, overexpression of PCBP2 in transfected cells suppressed VSV growth. Further studies revealed that PCBP2 negatively regulates overall viral mRNA accumulation and subsequent genome replication. Coimmunoprecipitation and immunofluorescence microscopic studies showed that …

Acute Fatty Liver Of Pregnancy: An Update On Mechanisms, Sathish Kumar Natarajan, Kavitha R. Thangaraj, Ashish Goel, C. E. Eapen, K. A. Balasubramanian, Anup Ramachandran

School of Veterinary and Biomedical Sciences: Faculty Publications

Acute fatty liver of pregnancy (AFLP), characterized by hepatic microvesicular steatosis, is a sudden catastrophic illness occurring almost exclusively in the third trimester of pregnancy. Defective fatty acid oxidation in the fetus has been shown to be associated with this disease. Since the placenta has the same genetic makeup as the fetus and as AFLP patients generally recover following delivery, we hypothesized that the placenta might be involved in pathogenesis of this disease. In an animal model of hepatic microvesicular steatosis (using sodium valproate), we found that microvesicular steatosis results in mitochondrial structural alterations and oxidative stress in subcellular organelles …

Glutaredoxin 2 Prevents H2o2-Induced Cell Apoptosis By Protecting Complex I Activity In The Mitochondria, Hongli Wu, Kuiyi Xing, Marjorie F. Lou

School of Veterinary and Biomedical Sciences: Faculty Publications

Glutaredoxin 2 (Grx2) belongs to the oxidoreductase family and is an isozyme of glutaredoxin 1 (Grx1) present in the mitochondria, however its function is not well understood. The purpose of this study is to evaluate the potential anti-apoptotic function of Grx2 by examining its ability to protect complex I in the mitochondrial electron transport system using human lens epithelial cells as a model. We found that cells treated with 200 μM hydrogen peroxide (H2O2) for 24 h exhibited decreased viability and became apoptotic with corresponding Bax up-regulation, Bcl-2 down-regulation, caspase 3 activation and mitochondrial cytochrome c leakage. Grx2 over-expression (OE) …

Regulation Of Cytosolic Phospholipase A2 (Cpla2) And Its Association With Cell Proliferation In Human Lens Epithelial Cells, Yin Wang, Kui-Yi Xing, Marjorie F. Lou

School of Veterinary and Biomedical Sciences: Faculty Publications

PURPOSE. To investigate the molecular mechanism for cytosolic phospholipase A2 (cPLA2) regulation and its association to platelet-derived growth factor (PDGF)-induced cell proliferation.

METHODS. cPLA2 was examined using human lens epithelial (HLE) B3 cells. Reactive oxygen species (ROS) generation induced by PDGF was analyzed by luminescence assay. Cell proliferation was measured by cell counting and by BrdU assay. Human cPLA2 gene was cloned via RT-PCR followed by sitedirected mutagenesis to construct HLE B3 cells expressing either inactive cPLA2 enzyme with S228A mutation (S228A), or cPLA2 truncated at the calcium-binding C2 domain (C2D). Activity of cPLA2 was measured by arachidonic acid (AA) …

Immune Evasion Of Porcine Reproductive And Respiratory Syndrome Virus Through Glycan Shielding Involves Both Glycoprotein 5 As Well As Glycoprotein 3, Hiep Vu, Byungjoon Kwon, Kyoung-Jin Yoon, William W. Laegreid, Asit K. Pattnaik, Fernando A. Osorio

School of Veterinary and Biomedical Sciences: Faculty Publications

Passive administration of porcine reproductive and respiratory syndrome virus (PRRSV) neutralizing antibodies (NAbs) can effectively protect pigs against PRRSV infection. However, after PRRSV infection, pigs typically develop a weak and deferred NAb response. One major reason for such a meager NAb response is the phenomenon of glycan shielding involving GP5, a major glycoprotein carrying one major neutralizing epitope. We describe here a type II PRRSV field isolate (PRRSV-01) that is highly susceptible to neutralization and induces an atypically rapid, robust NAb response in vivo. Sequence analysis shows that PRRSV-01 lacks two N-glycosylation sites, normally present in wild-type (wt) PRRSV strains, …

Complete Genome Sequence Of Mycoplasma Suis And Insights Into Its Biology And Adaption To An Erythrocyte Niche, Ana Ms Guimaraes, Andrea P. Santos, Phillip Sanmiguel, Thomas Walter, Jorge Timenetsky, Joanne Messick

Department of Comparative Pathobiology Faculty Publications

Mycoplasma suis, the causative agent of porcine infectious anemia, has never been cultured in vitro and mechanisms by which it causes disease are poorly understood. Thus, the objective herein was to use whole genome sequencing and analysis of M. suis to define pathogenicity mechanisms and biochemical pathways. M. suis was harvested from the blood of an experimentally infected pig. Following DNA extraction and construction of a paired end library, whole-genome sequencing was performed using GS-FLX (454) and Titanium chemistry. Reads on paired-end constructs were assembled using GS De Novo Assembler and gaps closed by primer walking; assembly was validated by …

Molecular Structures Of Prrsv That Contribute To Prrsv Protective Immunity, Asit K. Pattnaik

School of Veterinary and Biomedical Sciences: Faculty Publications

One of the objectives of the proposal is to delineate the regions of the two glycoproteins (GP2 and GP4) of PRRSV that interact with CD163. Other objectives of the proposal are to generate antibodies to these small regions of the glycoproteins as well as to the full-length proteins for future studies to determine if any of these antibodies possess PRRSV neutralizing activity.

To carry out the studies in the proposed objectives, we generated a series of mutants of GP2 as well as GP4 proteins in which various regions were specifically removed by manipulating the plasmids encoding these proteins. We then …

Low Levels Of Hydrogen Peroxide Stimulate Corneal Epithelial Cell Adhesion, Migration, And Wound Healing, Qing Pan, Wen-Ya Qiu, Ya-Nan Huo, Yu-Feng Yao, Marjorie F. Lou

School of Veterinary and Biomedical Sciences: Faculty Publications

PURPOSE. Intracellular reactive oxygen species have been reported to associate with growth factor and integrin signalings in promoting cell adhesion in many cell types. This study is to explore if exogenous H2O2 at low levels can be beneficial to cell adhesion, migration, and wound healing.

METHODS. Primary rabbit corneal epithelial cells treated with 0–70 M H2O2 were tested for viability by MTT assay, adhesion by centrifugation assay, focal contacts of vinculin and F-actin by immunofluorescence, activated Src(pY416), EGF receptor (pY845), vinculin(pY1065), FAK(pY397), and FAK(pY576) by immunoblotting. Cell migration was examined with 0–50 M H2O2 using the scratch wound technique. Corneal …

Roles Of The 15-Kda Selenoprotein (Sep15) In Redox Homeostasis And Cataract Development Revealed By The Analysis Of Sep 15 Knockout Mice, Marina V. Kasaikina, Dmitri E. Fomenko, Vyacheslav M. Labunskyy, Salil A. Lachke, Wenya Qiu, Juliet A. Moncaster, Jie Zhang, Mark W. Wojnarowicz, Sathish Kumar Natarajan, Mikalai I. Malinouski, Ulrich Schweizer, Petra A. Tsuji, Bradley A. Carlson, Richard L. Maas, Marjorie F. Lou, Lee E. Goldstein, Dolph L. Hatfield, Vadim N. Gladyshev

School of Veterinary and Biomedical Sciences: Faculty Publications

The 15-kDa selenoprotein (Sep15) is a thioredoxin-like, endoplasmic reticulum-resident protein involved in the quality control of glycoprotein folding through its interaction with UDP-glucose:glycoprotein glucosyltransferase. Expression of Sep15 is regulated by dietary selenium and the unfolded protein response, but its specific function is not known. In this study, we developed and characterized Sep15 KO mice by targeted removal of exon 2 of the Sep15 gene coding for the cysteinerich UDP-glucose:glycoprotein glucosyltransferase-binding domain. These KO mice synthesized a mutant mRNA, but the shortened protein product could be detected neither in tissues nor in Sep15 KO embryonic fibroblasts. Sep15 KO mice were viable …

Arbovirus Phenotype Alters Transmission Potential, Rebecca C. Christofferson

LSU Doctoral Dissertations

Extrinsic and environmental factors are known to affect the transmission of arthropod-borne viruses (arboviruses), including variations in the arthropod vector populations. Differences among these factors have been associated with differential transmission and are sometimes used to control the spread of an arbovirus through a vertebrate population in an effort to prevent or disrupt an outbreak. However, diversity in intrinsic viral populations, such as genetic and phenotypic variability, is not often accounted for when considering alterations in transmission. Presented in this dissertation are four experimental studies that explore the contribution of viral intrinsic factors, especially phenotypic variability, to the transmission potential …

The Tick Response To Rickettsial Dissemination During Typical And Atypical Rickettsial Infection, Piyanate Sunyakumthorn

LSU Doctoral Dissertations

Ticks are the only disease vectors for spotted fever group (SFG) Rickettsia which are obligate intracellular bacteria belonging to the genus Rickettsia. In nature, ticks maintain the infection of SFG Rickettsia via vertical and horizontal transmission. However, the prevalence of rickettsial transmission is limited to certain species of ticks, and this limitation is known as a specific tick/Rickettsia relationship. Due to the continuous increase of tick-borne rickettsial disease cases in the United States, which contrasts with very low prevalence of Rickettsia in tick vectors, the study of vector competence of tick to Rickettsia is needed in order to understand the …

Mapping And Modeling Of Neglected Tropical Diseases In Brazil And Bolivia, Paula Mischler

LSU Doctoral Dissertations

Accurately defining disease distributions and calculating disease risk is an important step in the control and prevention of diseases. This study used geographical information systems and remote sensing technologies within the MaxEnt ecological niche modeling program to create predictive risk maps for leprosy and Schistosomiasis in Brazil and Chagas disease in both Brazil and Bolivia. New disease cases were compiled for leprosy, Schistosomiasis, and Chagas disease from the Brazilian ministry of Health for 2001 to 2009 and the data was stratified to a 10,000 population for each municipality. Bolivian Chagas prevalence rates were calculated from 2007 to 2009 survey data. …

Development, Optimization, And Validation Of A Classical Swine Fever Virus Real-Time Reverse Transcription Polymerase Chain Reaction Assay, August J. Eberling, Jill Bieker-Stefanelli, Monica M. Reising, David Siev, Barbara M. Martin, Michael T. Mcintosh, Tammy R. Beckham

Zoonotics and Wildlife Disease: Publications

Classical swine fever (CSF) is an economically devastating disease of pigs. Instrumental to the control of CSF is a well-characterized assay that can deliver a rapid, accurate diagnosis prior to the onset of clinical signs. A real-time fluorogenicprobe hydrolysis (TaqMan) reverse transcription polymerase chain reaction (RT-PCR) for CSF was developed by the United States Department of Agriculture (USDA) at the Plum Island Animal Disease Center (CSF PIADC assay) and evaluated for analytical and diagnostic sensitivity and specificity. A well-characterized panel including Classical swine fever virus (CSFV), Bovine viral diarrhea virus (BVDV), and Border disease virus (BDV) isolates was utilized in …

Carbenoxolone Blocks The Light-Evoked Rise In Intracellular Calcium In Isolated Melanopsin Ganglion Cell Photoreceptors, Jayne R. Bramley, Erin M. Wiles, Patricia J. Sollars, Gary E. Pickard

School of Veterinary and Biomedical Sciences: Faculty Publications

Background: Retinal ganglion cells expressing the photopigment melanopsin are intrinsically photosensitive (ipRGCs). These ganglion cell photoreceptors send axons to several central targets involved in a variety of functions. Within the retina ipRGCs provide excitatory drive to dopaminergic amacrine cells via glutamatergic signals and ipRGCs are coupled to widefield GABAergic amacrine cells via gap junctions. However, the extent to which ipRGCs are coupled to other retinal neurons in the ganglion cell layer via gap junctions is unclear. Carbenoxolone, a widely employed gap junction inhibitor, greatly reduces the number of retinal neurons exhibiting non-rod, non-cone mediated light-evoked Ca²⁺ signals suggesting extensive …

Y-Like Retinal Ganglion Cells Innervate The Dorsal Raphe Nucleus In The Mongolian Gerbil (Meriones Unguiculatus), Liju Luan, Chaoran Ren, Benson Wui-Man Lau, Jian Yang, Gary E. Pickard, Kwok-Fai So, Mingliang Pu

School of Veterinary and Biomedical Sciences: Faculty Publications

Background: The dorsal raphe nucleus (DRN) of the mesencephalon is a complex multi-functional and multi-transmitter nucleus involved in a wide range of behavioral and physiological processes. The DRN receives a direct input from the retina. However little is known regarding the type of retinal ganglion cell (RGC) that innervates the DRN. We examined morphological characteristics and physiological properties of these DRN projecting ganglion cells.

Methodology/Principal Findings: The Mongolian gerbils are highly visual rodents with a diurnal/crepuscular activity rhythm. It has been widely used as experimental animals of various studies including seasonal affective disorders and depression. Young adult gerbils were used …

Challenges And Opportunities For Toxicology In Mexico, Rodrigo Franco, Balam Muñoz

School of Veterinary and Biomedical Sciences: Faculty Publications

We have developed this Special Issue titled “Challenges and Opportunities for Toxicology in Mexico” with the aim to highlight not only the challenges toxicology research faces in Mexico, but also the efforts and drive towards cutting edge research to address them. Altogether, this special issue should be a valuable source of information for all readers with an interest in toxicology and human health.

Mexico is an important economy worldwide and is a major exporter of several supplies and commodities. Because of this, its industry is a source of occupational exposure to several chemical derivatives (Nieusma 2011). The situation of occupational …

Intrinsically Photosensitive Retinal Ganglion Cells, Gary E. Pickard, Patricia J. Sollars

School of Veterinary and Biomedical Sciences: Faculty Publications

Intrinsically photosensitive retinal ganglion cells (ipRGCs) respond to light in the absence of all rod and cone photoreceptor input. The existence of these ganglion cell photoreceptors, although predicted from observations scattered over many decades, was not established until it was shown that a novel photopigment, melanopsin, was expressed in retinal ganglion cells of rodents and primates. Phototransduction in mammalian ipRGCs more closely resembles that of invertebrate than vertebrate photoreceptors and appears to be mediated by transient receptor potential channels. In the retina, ipRGCs provide excitatory drive to dopaminergic amacrine cells and ipRGCs are coupled to GABAergic amacrine cells via gap …

Long-Term Clinicopathological Characteristics Of Alpacas Naturally Infected With Bovine Viral Diarrhea Virus Type Ib, D. Bedenice, Edward J. Dubovi, Clayton Kelling, Jamie N Henningson, Christina L. Topliff, N. Parry

School of Veterinary and Biomedical Sciences: Faculty Publications

Background: Substantial bovine viral diarrhea virus (BVDV)-related production losses in North American alpaca herds have been associated with BVDV type Ib infection.

Objectives: To classify and differentiate the long-term clinicopathological characteristics of BVDV type Ib infection of al- paca crias, after natural virus exposure. We hypothesized that persistently infected (PI) alpacas specifically demonstrate growth retardation, clinicopathological evidence of opportunistic infections, and early mortality.

Animals: Thirty-five crias naturally exposed to BVDV (18 acute, 3 chronic, 14 PIs), and 19 healthy cohort controls of 5 northeastern alpaca farms were prospectively evaluated over 2 years (September 2005–September 2008).

Methods: Observational cohort-control study.

Results: …

Rnai Screening Reveals Requirement For Host Cell Secretory Pathway In Infection By Diverse Families Of Negative-Strand Rna Viruses, Debasis Panda, Anshuman Das, Phat X. Dinh, Sakthivel Subramaniam, Debasis Nayak, Nicholas J. Barrows, James L. Pearson, Jesse Thompson, David L. Kelly, Istvan Ladunga, Asit K. Pattnaik

School of Veterinary and Biomedical Sciences: Faculty Publications

Negative-strand (NS) RNA viruses comprise many pathogens that cause serious diseases in humans and animals. Despite their clinical importance, little is known about the host factors required for their infection. Using vesicular stomatitis virus (VSV), a prototypic NS RNA virus in the family Rhabdoviridae, we conducted a human genomewide siRNA screen and identified 72 host genes required for viral infection. Many of these identified genes were also required for infection by two other NS RNA viruses, the lymphocytic choriomeningitis virus of the Arenaviridae family and human parainfluenza virus type 3 of the Paramyxoviridae family. Genes affecting different stages of …

Consensus-Based Reporting Standards For Diagnostic Test Accuracy Studies For Paratuberculosis In Ruminants, Ian A. Gardner, Søren S. Nielsen, Richard J. Wittington, Michael T. Collins, Douwe Bakker, Beth Harris, Srinand Sreevatsan, Jason E. Lombard, Raymond Sweeney, David R. Smith, Jerrie Gavalchin, Shigetoshi Eda

School of Veterinary and Biomedical Sciences: Faculty Publications

The Standards for Reporting of Diagnostic Accuracy (STARD) statement was developed to encourage complete and transparent reporting of key elements of test accuracy studies in human medicine. The statement was motivated by widespread evidence of bias in test accuracy studies and the finding that incomplete or absent reporting of items in the STARD checklist was associated with overly optimistic estimates of test performance characteristics. Although STARD principles apply broadly, specific guidelines do not exist to account for unique considerations in livestock studies such as herd tests, potential use of experimental challenge studies, a more diverse group of testing purposes and …

Characterization Of Spiroplasma Mirum And Its Role In Transmissible Spongiform Encephalopathies, Hilari Maree French

LSU Doctoral Dissertations

There are many contradictory reports in the literature involving the culture of Spiroplasma mirum, its resistance to disinfectants and antibiotics, and its potential role in Transmissible Spongiform Encephalopathies (TSEs). These contradictions led to an interest in a possible link between spiroplasma and TSEs and the development of a research plan to elucidate this connection. It was hypothesized that Spiroplasma was associated with a neurodegenerative disease such as TSE. In this work we further characterized S. mirum laboratory strains and continued to evaluate the possible correlations they have with TSE infections and the prion. To optimize recovery of S. mirum from …

Arginine Metabolism In The Edwardsiella Ictaluri- Channel Catfish Macrophage Dynamic, Wes Arend Baumgartner

LSU Doctoral Dissertations

Edwardsiella ictaluri encodes a urease operon and an arginine decarboxylase (AdiA) that are required for virulence in head kidney derived macrophages (HKDM). The urease produces ammonia in amounts sufficient to alter environmental pH from acid to neutral. A hypothetical model was proposed, involving arginine metabolism in E. ictaluri infected HKDM, focusing on bacterial urease, AdiA, a second arginine decarboxylase (SpeA), and agmatinase (SpeB). Using fluorescence based ratiometric pH determination of E. ictaluri in live HKDM, it was shown that E. ictaluri modulates HKDM phagosome pH to above six. Urease and AdiA mutants failed to up-regulate vacuole pH, while vacuole pH …