Veterinary Pathology and Pathobiology Commons^™

Amblyomma Maculatum Immunomodulation In Mammalian Models Of Rickettsia Parkeri Rickettsiosis, Kaikhushroo Hormazd Banajee

LSU Doctoral Dissertations

Rickettsia parkeri is an emerging human pathogen and spotted fever group Rickettsia that is transmitted via Amblyomma maculatum (the Gulf Coast tick) in the United States. Since these ticks must feed for several days in order to molt to the next life cycle, they must be able to counteract the host immune response. Despite this fact, there have been few studies that evaluate the immunomodulatory effect of this vector and the resultant influence on rickettsial disease. The hypothesis of this research is that, if A. maculatum feeding modifies the host immune response, this immunomodulation will enhance disease caused by R. …

Rickettsia Felis, Transmission Mechanisms Of An Emerging Flea-Borne Rickettsiosis, Lisa Diane Brown

LSU Doctoral Dissertations

Rickettsia felis is an emerging insect-borne rickettsial pathogen and the causative agent of flea-borne spotted fever. First described as a human pathogen from the United States in 1991, R. felis is now identified throughout the world and considered a common cause of fever in Africa. The cosmopolitan distribution of this pathogen is credited to the equally widespread occurrence of cat fleas (Ctenocephalides felis), the primary vector and reservoir of R. felis. Additionally, R. felis has been identified in other hematophagous arthropods (including numerous species of fleas, ticks, mosquitoes, and mites). Most transmission cycles of pathogenic Rickettsia include transovarial and transstadial …

Identification And Characterization Of A Relish-Type Nf-Kb, Dvrelish In Dermacentor Variabilis, The American Dog Tick, Victoria Irene Verhoeve

LSU Doctoral Dissertations

Ticks are important worldwide as vectors of bacteria, viruses, and parasites. Pathogenic and non-pathogenic Spotted fever group (SFG) Rickettsia are maintained and transmitted by ticks with specific hard tick-Rickettsia pairings evident in nature. The pathogenic SFG Rickettsia rickettsii is transmitted by the hard tick Dermacentor variabilis. In response to infection, D. variabilis is known differentially respond to SFG Rickettsia infection. The mechanisms of differential immune induction are currently unknown, and are likely involved in the establishment of specific tick-SFG Rickettsia pairings. It was hypothesized that the level of response by D. variabilis to SFG Rickettsia occurs in a species-specific manner, …

Mosquito Host Choices On Livestock Amplifiers Of Rift Valley Fever Virus In Kenya, David P. Tchouassi, Robinson O. Okiro, Rosemary Sang, Lee W. Cohnstaedt, D. Scott Mcvey, Baldwyn Torto

School of Veterinary and Biomedical Sciences: Faculty Publications

Background: Animal hosts may vary in their attraction and acceptability as components of the host location process for assessing preference, and biting rates of vectors and risk of exposure to pathogens. However, these parameters remain poorly understood for mosquito vectors of the Rift Valley fever (RVF), an arboviral disease, and for a community of mosquitoes.

Methods: Using three known livestock amplifiers of RVF virus including sheep, goat and cattle as bait in enclosure traps, we investigated the host-feeding patterns for a community of mosquitoes in Naivasha, an endemic area of Rift Valley fever (RVF), in a longitudinal study for six …

Analysis Of Mycobacterium Avium Subsp. Paratuberculosis Mutant Libraries Reveals Loci-Dependent Transposition Biases And Strategies For Novel Mutant Discovery, Govardhan Rathnaiah, John Bannantine, Darrell O. Bayles, Denise K. Zinniel, Judith R. Stabel, Yrjö T. Gröhn, Raúl G. Barletta

School of Veterinary and Biomedical Sciences: Faculty Publications

Mycobacterium avium subsp. paratuberculosis (MAP), the aetiological agent of Johne’s disease, is one of the most important bacterial pathogens in ruminants. A thorough understanding of MAP pathogenesis is needed to develop new vaccines and diagnostic tests. The generation of comprehensive random transposon mutant libraries is a fundamental genetic technology to determine the role of genes in physiology and pathogenesis. In this study, whole MAP genome analysis compared the insertion sites for the mycobacterial transposon Tn5367 derived from the Mycobacterium smegmatis insertion sequence IS1096 and the mariner transposon MycoMarT7 carrying the Himar1 transposase. We determined that only MycoMarT7 provides …

A Synthetic Porcine Reproductive And Respiratory Syndrome Unprecedented Levels Of Heterologous Protection, Hiep Vu, Fangrui Ma, William W. Laegreid, Asit K. Pattnaik, David Steffen, Alan R. Doster, Fernando A. Osorio

School of Veterinary and Biomedical Sciences: Faculty Publications

Current vaccines do not provide sufficient levels of protection against divergent porcine reproductive and respiratory syndrome virus (PRRSV) strains circulating in the field, mainly due to the substantial variation of the viral genome. We describe here a novel approach to generate a PRRSV vaccine candidate that could confer unprecedented levels of heterologous protection against divergent PRRSV isolates. Using a set of 59 non-redundant, full genome sequences of type-2 PRRSV, a consensus genome (designated as PRRSV-CON) was these 59 PRRSV full genome sequences, followed by selecting the most common nucleotide found at each position of the alignment. Next, the synthetic PRRSV-CON …

Overview Of Rhabdo- And Filoviruses, Asit K. Pattnaik, Michael A. Whitt

School of Veterinary and Biomedical Sciences: Faculty Publications

Enveloped viruses with a negative-sense, single-stranded monopartite RNA genome have been classified into the order Mononegavirales. Five families of viruses that constitute the order are: Rhabdoviridae, Filoviridae, Paramyxoviridae, Bornaviridae and Nyamiviridae. Members of these families possess a helical nucleocapsid core containing the viral genome and a host-derived lipid envelope containing viral proteins. This introductory chapter provides a brief overview of the Rhabdoviridae and the Filoviridae, the two families of viruses that are the subject of this book. Many members of these two families are highly significant human and animal pathogens. The rationale and goal of the book is to …

On And Off Retinal Ganglion Cells Differentially Regulate Serotonergic And Gabaergic Activity In The Dorsal Raphe Nucleus, Ting Zhang, Lu Huang, Li Zhang, Minjie Tan, Mingliang Pu, Gary E. Pickard, Kwok -Fai So, Chaoran Ren

School of Veterinary and Biomedical Sciences: Faculty Publications

The dorsal raphe nucleus (DRN), the major source of serotonergic input to the forebrain, receives excitatory input from the retina that can modulate serotonin levels and depressive-like behavior. In the Mongolian gerbil, retinal ganglion cells (RGCs) with alpha-like morphological and Y-like physiological properties innervate the DRN with ON DRN-projecting RGCs out numbering OFF DRN-projecting RGCs. The DRN neurons targeted by ON and OFF RGCs are unknown. To explore retino-raphe anatomical organization, retinal afferents labeled with Cholera toxin B were examined for association with the postsynaptic protein PSD-95. Synaptic associations between retinal afferents and DRN serotonergic and GABAergic neurons were observed. …

Host Cell Functions In Vesicular Stomatitis Virus Replication, Phat X. Dinh, Anshuman Das, Asit K. Pattnaik

School of Veterinary and Biomedical Sciences: Faculty Publications

Vesicular stomatitis virus (VSV), the prototypic rhabdovirus, has been used as an excellent paradigm for understanding the mechanisms of virus replication, pathogenesis, host response to virus infection and also for myriads of studies on cellular and molecular biology. Biochemical studies as well as high-throughput genomics, proteomics, and chemical approaches have revealed a plethora of cellular factors and pathways that regulate replication of VSV. These factors include those that support virus replication and also those that restrict its replication. This chapter discusses the role(s) of many of these host cell factors and pathways involved in VSV replication. Although mechanistic understanding of …

Resolving Bovine Viral Diarrhea Virus Subtypes From Persistently Infected U.S. Beef Calves With Complete Genome Sequence, Aspen M. Workman, Michael P. Heaton, Gregory P. Harhay, Timothy P.L. Smith, Dale M. Grotelueschen, David Sjeklocha, Bruce Brodersen, Jessica L. Petersen, Carol G. Chitko-Mckown

School of Veterinary and Biomedical Sciences: Faculty Publications

Bovine viral diarrhea virus (BVDV) is classified into 2 genotypes, BVDV-1 and BVDV-2, each of which contains distinct subtypes with genetic and antigenic variation. To effectively control BVDV by vaccination, it is important to know which subtypes of the virus are circulating and how their prevalence is changing over time. Accordingly, the purpose of our study was to estimate the current prevalence and diversity of BVDV subtypes from persistently infected (PI) beef calves in the central United States. Phylogenetic analysis of the 5′-UTR (5′ untranslated region) for 119 virus strains revealed that a majority (82%) belonged to genotype 1b, and …

New Tools To Convert Bacterial Artificial Chromosomes To A Self-Excising Design And Their Application To A Herpes Simplex Virus Type 1 Infectious Clone, Alexsia L. Richards, Patricia J. Sollars, Gregory A. Smith

School of Veterinary and Biomedical Sciences: Faculty Publications

Background: Infectious clones are fundamental tools for the study of many viruses, allowing for efficient mutagenesis and reproducible production of genetically-defined strains. For the large dsDNA genomes of the herpesviridae, bacterial artificial chromosomes have become the cloning vector of choice due to their capacity to house full-length herpesvirus genomes as single contiguous inserts. Furthermore, while maintained as plasmids in Escherichia coli, the clones can be mutated using robust prokaryotic recombination systems. An important consideration in the design of these clones is the means by which the vector backbone is removed from the virus genome upon delivery into mammalian cells. …

The Mechanistic Basis Of Hemoglobin Adaptation In The High-Flying Barheaded Goose: Insights From Ancestral Protein Resurrection, Chandrasekhar Natarajan, Amit Kumar, Hideaki Moriyama, Roy E. Weber, Angela Fago, Jay F. Storz

School of Veterinary and Biomedical Sciences: Faculty Publications

The bar-headed goose (‘BHG’, Anser indicus) is renowned for its trans-Himalayan migratory flights, and the elevated hemoglobin (Hb)-O2 affinity of this species is thought to make a key contribution to its capacity for powered flight at elevations of ~9000 m. Here we revisit the molecular basis of this text-book example of biochemical adaptation. Previous hypotheses about the molecular basis of the evolved increase in Hb-O2 affinity were tested by engineering BHGspecific mutations into recombinant human Hb. This approach can provide important insights, but one problem with such ‘horizontal’ comparisons – swapping residues between proteins of contemporary species – is that …

Maporal Hantavirus Causes Mild Pathology In Deer Mice (Peromyscus Maniculatus), Amanda Mcguire, Kaitlyn Miedema, Joseph R. Fauver, Amber Rico, Tawfik Aboellail, Sandra L. Quackenbush, Ann Hawkinson, Tony Schountz

School of Veterinary and Biomedical Sciences: Faculty Publications

Rodent-borne hantaviruses can cause two human diseases with many pathological similarities: hantavirus cardiopulmonary syndrome (HCPS) in the western hemisphere and hemorrhagic fever with renal syndrome in the eastern hemisphere. Each virus is hosted by specific reservoir species without conspicuous disease. HCPS-causing hantaviruses require animal biosafety level-4 (ABSL-4) containment, which substantially limits experimental research of interactions between the viruses and their reservoir hosts. Maporal virus (MAPV) is a South American hantavirus not known to cause disease in humans, thus it can be manipulated under ABSL-3 conditions. The aim of this study was to develop an ABSL-3 hantavirus infection model using the …

Localization Of Cd8 T Cell Epitope Within Cardiac Myosin Heavy Chain-Α334-352 That Induces Autoimmune Myocarditis In A/J Mice, Chandirasegara Massilamany, Arunakumar Gangaplara, Rakesh H. Basavalingappa, Rajkumar A. Rajasekaran, Vahid Khalilzad-Sharghi, Zhongji Han, Shadi F. Othman, David Steffen, Jay Reddy

School of Veterinary and Biomedical Sciences: Faculty Publications

Background—Cardiac myosin heavy chain-α (Myhc), an intracellular protein expressed in the cardiomyocytes, has been identified as a major autoantigen in cardiac autoimmunity. In our studies with Myhc_334-352-induced experimental autoimmune myocarditis in A/J mice (H-2a), we discovered that Myhc_334-352, supposedly a CD4 T cell epitope, also induced antigen-specific CD8 T cells that transfer disease to naïve animals.

Methods and Results—In our efforts to identify the CD8 T cell determinants, we localized Myhc_338-348 within the full length-Myhc_334-352, leading to four key findings. (1) By acting as a dual epitope, Myhc_338-348 induces both …

Note On Ehrlichia Chaffeensis, Ehrlichia Ewingii, And “Borrelia Lonestari” Infection In Lone Star Ticks (Acari: Ixodidae), Nebraska, Usa, Amanda Maegli, J. Dustin Loy, Roberto Cortinas

School of Veterinary and Biomedical Sciences: Faculty Publications

The lone star tick, Amblyomma americanum (L.) (Acari: Ixodidae), is established in southeastern Nebraska, yet the prevalence of tick-associated microorganisms is not known. An initial PCR-based analysis for Ehrlichia chaffeensis, Ehrlichia ewingii, and Borrelia infection in host-seeking adult ticks collected in southeast Nebraska was conducted. A total of 251 adult ticks collected in six sites in southeast Nebraska were tested. E. chaffeensis, E. ewingii, and Borrelia spp. were present, and the prevalence of each was approximately 1.6%. This study demonstrates that Ehrlichia spp. are present in Nebraska lone star tick populations.

Expression And Distribution Of Thiol-Regulating Enzyme Glutaredoxin 2 (Grx2) In Porcine Ocular Tissues, Bijaya Upadhyaya, Xiaoli Tian, Hongli Wu, Marjorie F. Lou

School of Veterinary and Biomedical Sciences: Faculty Publications

Glutaredoxin2 (Grx2) is a mitochondrial isozyme of the cytosolic glutaredoxin1 (thioltransferase or TTase). Both belong to the large oxidoreductase family and play an important role in maintaining thiol/disulfide redox homeostasis in the cells. Grx2 is recently found in the lens where its activities of disulfide reductase and peroxidase, similar to TTase, can protect the lens against oxidative stress. Since other eye tissues are also highly sensitive to oxidative stress, and TTase’s distribution in the eye is known, we focused on this study by investigating the Grx2 distribution in the ocular tissues in comparison to the lens. Fresh porcine eyes were …

Autoimmunity In Picornavirus Infections, Chandirasegara Massilamany, Andreas Koenig, Jay Reddy, Sally Huber, Iwona Buskiewicz

School of Veterinary and Biomedical Sciences: Faculty Publications

Enteroviruses are small, non-enveloped, positive-sense singlestrand RNA viruses, and are ubiquitously found throughout the world. These viruses usually cause asymptomatic or mild febrile illnesses, but have a propensity to induce severe diseases including type 1 diabetes and pancreatitis, paralysis and neuroinflammatory disease, myocarditis, or hepatitis. This pathogenicity may result from induction of autoimmunity to organ-specific antigens. While enterovirus-triggered autoimmunity can arise from multiple mechanisms including antigenic mimicry and release of sequestered antigens, the recent demonstration of T cells expressing dual T cell receptors arising as a natural consequence of Theiler’s virus infection is the first demonstration of this autoimmune mechanism.

Genome-Wide Search For Host Association Factors During Ovine Progressive Pneumonia Virus Infection, Jesse Thompson, Fangrui Ma, Meghan Quinn, Shi-Hua Xiang

School of Veterinary and Biomedical Sciences: Faculty Publications

Ovine progressive pneumonia virus (OPPV) is an important virus that causes serious diseases in sheep and goats with a prevalence of 36% in the USA. Although OPPV was discovered more than half of a century ago, little is known about the infection and pathogenesis of this virus. In this report, we used RNA-seq technology to conduct a genome-wide probe for cellular factors that are associated with OPPV infection. A total of approximately 22,000 goat host genes were detected of which 657 were found to have been significantly up-regulated and 889 down-regulated at 12 hours post-infection. In addition to previously known …

From Crystal Structure Of Α-Conotoxin Gic In Complex With Ac-Achbp To Molecular Determinants Of Its High Selectivity For Α3Β2 Nachr, Bo Lin, Manyu Xu, Xiaopeng Zhu, Yong Wu, Xi Liu, Dongting Zhangsun, Yuanyan Hu, Shi-Hua Xiang, Igor E. Kasheverov, Victor I. Tsetlin, Xinquan Wang, Sulan Luo

School of Veterinary and Biomedical Sciences: Faculty Publications

Acetylcholine binding proteins (AChBPs) are unique spatial homologs of the ligand-binding domains of nicotinic acetylcholine receptors (nAChRs), and they reproduce some pharmacological properties of nAChRs. X-ray crystal structures of AСhBP in complex with α-conotoxins provide important insights into the interactions of α-conotoxins with distinct nAChR subtypes. Although considerable efforts have been made to understand why α-conotoxin GIC is strongly selective for α3β2 nAChR, this question has not yet been solved. Here we present the structure of α-conotoxin GIC in complex with Aplysia californica AChBP (Ac-AChBP) at a resolution of 2.1 Å. Based on this co-crystal structure complemented with molecular docking …

From Crystal Structure Of Α-Conotoxin Gic In Complex With Ac-Achbp To Molecular Determinants Of Its High Selectivity For Α3Β2 Nachr, Bo Lin, Manyu Xu, Xiaopeng Zhu, Yong Wu, Xi Liu, Dongting Zhangsun, Yuanyan Hu, Shi-Hua Xiang, Igor E. Kasheverov, Victor I. Tsetlin, Xianquan Wang, Sulan Luo

School of Veterinary and Biomedical Sciences: Faculty Publications

Acetylcholine binding proteins (AChBPs) are unique spatial homologs of the ligand-binding domains of nicotinic acetylcholine receptors (nAChRs), and they reproduce some pharmacological properties of nAChRs. X-ray crystal structures of AСhBP in complex with α-conotoxins provide important insights into the interactions of α-conotoxins with distinct nAChR subtypes. Although considerable efforts have been made to understand why α-conotoxin GIC is strongly selective for α3β2 nAChR, this question has not yet been solved. Here we present the structure of α-conotoxin GIC in complex with Aplysia californica AChBP (Ac-AChBP) at a resolution of 2.1 Å. Based on this co-crystal structure complemented with molecular docking …