Virology Commons^™

Dynamic Attachment Of Chlorovirus Pbcv-1 To Chlorella Variabilis, Irina Agarkova, Brigitte Hertel, Xinzheng Zhang, Les Lane, Alexander Tchourbanov, David D. Dunigan, Gerhard Thiel, Michael G. Rossmann, James L. Van Etten

Nebraska Center for Virology: Faculty Publications

Chloroviruses infect their hosts by specifically binding to and degrading the cell wall of their algal hosts at the site of attachment, using an intrinsic digesting enzyme(s). Chlorovirus PBCV-1 stored as a lysate survived longer than virus alone, suggesting virus attachment to cellular debris may be reversible. Ghost cells (algal cells extracted with methanol) were used as a model to study reversibility of PBCV-1 attachment because ghost cells are as susceptible to attachment and wall digestion as are live cells. Reversibility of attachment to ghost cells was examined by releasing attached virions with a cell wall degrading enzyme extract. The …

Cell- And Virus-Mediated Regulation Of The Barrier-To-Autointegration Factor’S Phosphorylation State Controls Its Dna Binding, Dimerization, Subcellular Localization, And Antipoxviral Activity, Augusta Jamin, April Wicklund, Matthew S. Wiebe

Nebraska Center for Virology: Faculty Publications

Barrier-to-autointegration factor (BAF) is a DNA binding protein with multiple cellular functions, including the ability to act as a potent defense against vaccinia virus infection. This antiviral function involves BAF’s ability to condense double-stranded DNA and subsequently prevent viral DNA replication. In recent years, it has become increasingly evident that dynamic phosphorylation involving the vaccinia virus B1 kinase and cellular enzymes is likely a key regulator of multiple BAF functions; however, the precise mechanisms are poorly understood. Here we analyzed how phosphorylation impacts BAF’s DNA binding, subcellular localization, dimerization, and antipoxviral activity through the characterization of BAF phosphomimetic and unphosphorylatable …

Host Entry Factors For Human Coronaviruses, Taylor Heald-Sargent

Dissertations

Coronaviruses infect a diverse range of animals from birds to pigs and cats to humans. Coronaviruses employ RNA-based replicative processes and as such are genetically adaptable to acquire novel host ranges. A coronavirus from one species can jump to another by shifting its entry requirements. As we learned from the Severe Acute Respiratory Syndrome (SARS) pandemic, this shift in species can have detrimental consequences. Thus, it is imperative that we understand the virus-host interaction during the entry process.

This dissertation focuses on host entry factors that influence human coronavirus entry. Recently, a new class of proteases, the type II transmembrane …

Characterizing Dsrna Production In Virus-Infected Fish Cells, Amal Brek Aloufi

Theses and Dissertations (Comprehensive)

Viral dsRNA is produced by almost all viruses sometime during their replicative cycle. These viral nucleic acids are potent inducers of both innate and adaptive immune responses, and are therefore considered important immuno-modulators. Previous studies have shown that viruses produce dsRNA when replicating in mammalian cells; however, to date no one has demonstrated viral dsRNA production in virus infected fish cells. Therefore, the goal of this study is to investigate dsRNA production by fish viruses in fish cells, verifying production and performing initial characterization of the dsRNA molecules being produced. Three different rainbow trout cell lines were used in this …

The Innate Antiviral Effects Of Extracellular Viral Dsrna In Rainbow Trout Cells, Sarah J. Poynter

Theses and Dissertations (Comprehensive)

Viral double-stranded RNA (dsRNA) molecules are a potent pathogen-associated molecular pattern and play a crucial role in the innate immune response. During a viral infection, extracellular and intracellular dsRNA can initiate pathways resulting in the production of type I interferons (IFNs) and interferon-stimulated genes (ISGs). The accumulation of ISGs within a cell results in a protective antiviral state. This study used both commercially available dsRNA (poly I:C) and in vitro transcribed dsRNA molecules, based on the viral hemorrhagic septicemia virus (VHSV) genome sequence, as stimuli to investigate the effects of these molecules on the innate immune response in rainbow trout …

The Sumoylation Of The Non-Structural Protein 1 Of The Influenza A Virus Plays A Dual Role During Viral Infection, Jason Michael Chacon

Open Access Theses & Dissertations

The potential for a highly pathogenic influenza pandemic remains a concern for global health. The ability of the influenza virus to undergo antigenic shift and genetic drift give circulating strains of influenza the high probability of developing resistance to current antiviral therapies. Emerging strains of higher virulence, to which the infected person has not had any previous exposure to viral antigens, pose a greater threat of serious illness and death. Currently, there is no antiviral therapy that is effective against all strains of influenza, emphasizing the need to develop new strategies that target cellular systems required for viral replication to …

Divergent Antibody Subclass And Specificity Profiles But Not Protective Hla-B Alleles Are Associated With Variable Antibody Effector Function Among Hiv-1 Controllers, Jennifer I. Lai, Anna F. Licht, Anne-Sophie Dugast, Todd Suscovich, Ickwon Choi, Chris Bailey-Kellogg, Galit Alter, Margaret E. Ackerman

Dartmouth Scholarship

Understanding the coordination between humoral and cellular immune responses may be the key to developing protective vaccines, and because genetic studies of long-term HIV-1 nonprogressors have associated specific HLA-B alleles with spontaneous control of viral replication, this subject group presents an opportunity to investigate relationships between arms of the adaptive immune system. Given evidence suggesting that cellular immunity may play a role in viral suppression, we sought to determine whether and how the humoral immune response might vary among controllers. Significantly, Fc-mediated antibody effector functions have likewise been associated with durable viral control. In this study, we compared the effector …

Use Of Irf-3 And/Or Irf-7 Knockout Mice To Study Viral Pathogenesis: Lessons From A Murine Retrovirus-Induced Aids Model, Megan A. O'Connor, William R. Green

Dartmouth Scholarship

Interferon regulatory factor (IRF) regulation of the type I interferon response has not been extensively explored in murine retroviral infections. IRF-3(-/-) and select IRF-3/7(-/-) mice were resistant to LP-BM5-induced pathogenesis. However, further analyses strongly suggested that resistance could be attributed to strain 129-specific contamination of the known retrovirus resistance gene Fv1. Therefore, caution should be taken when interpreting phenotypes observed in these knockout mice, as strain 129-derived genetic polymorphisms may explain observed differences.

Impact Of Wheat Streak Mosaic Virus And Triticum Mosaic Virus On Transmission By Aceria Tosichella Keifer (Eriophyidae) And Virus Epidemiology In Wheat, Camila F. De Oliveira

Department of Entomology: Dissertations, Theses, and Student Research

The wheat curl mite (WCM), Aceria tosichella Keifer, transmits a complex of viruses, Wheat streak mosaic virus (WSMV), Triticum mosaic virus (TriMV) and Wheat mosaic virus (WMoV), to wheat, Triticum aestivum, in the Great Plains. Co-infection of wheat by these viruses is frequently observed, increasing disease severity and yield loss.

Current genetic work classifies WCM populations into two genotypes, Type 1 and Type 2. It has been shown that different mite genotypes are able to transmit viruses at varying rates. WCM-virus relations are very specific and can impact vector biology. In this study, the primary objective was to determine …

Characterization Of The Role(S) Of Env Protein Of Human Endogenous Retrovirus-K In Multiple Human Cancers, Ming Li

Dissertations and Theses (Open Access)

Human endogenous retroviruses (HERVs) are remnants from ancient retroviral infections, and most of them are inactive in normal tissues. One family of HERV, HERV-K, is found to be associated with multiple human cancers including breast cancer, pancreatic cancer and melanoma, but the causal relationship between HERV-K and cancer is still unclear. Increased expression of HERV-K in melanoma cells correlates with malignant transformation, while a serological response to HERV-K in breast cancer or melanoma patients correlates with survival probability. However, the mechanism behind these observations remains obscure. Our laboratory reported that anti-HERV-K envelope (Env) protein antibodies show antitumor potential in targeting …

C-Jun N-Terminal Kinases Regulate Adenovirus-Mediated Autophagy And Antigen Presentation, Sarah R. Klein

Dissertations and Theses (Open Access)

Targeted immunotherapy with recombinant, oncolytic adenoviruses is under investigation for the treatment of cancer. Evidence indicates adenoviruses induce autophagy that is required for oncolysis, but the molecular regulation of autophagy in infected cells remains under investigation. Our data suggested the canonical pathway regulating starvation-induced autophagy was not implemented in adenovirus-induced autophagy; however, adenovirus infection triggered phosphorylation of c-Jun N-terminal kinases (JNK) that was essential for autophagy. Adenoviral replication within the host cell elicited JNK pathway activation leading to B cell lymphoma-2 (Bcl-2) phosphorylation. JNK-dependent Bcl-2 phosphorylation stimulated the dissociation of Bcl-2/beclin 1 heterodimers, enabling beclin 1 to initiate autophagy. Moreover, …

Study Of Coronavirus Protease Using Cfp-Yfp Fluorescent Assay, Caitlin E. Specht, Andrew Mesecar Ph.D., Katrina Molland Ph.D.

The Summer Undergraduate Research Fellowship (SURF) Symposium

Middle Eastern Respiratory Syndrome (MERS) is an emerging viral disease originating in the Arabian Peninsula with a current mortality rate of nearly fifty percent throughout Europe and Asia according to the World Health Organization. Characterization of this disease is being done to understand the basis of viral replication. One target for viral inhibition are replication proteases. Replication proteases are enzymes that cleave proteins specific to cell growth and reproduction that form the viral replicase complex making them an ideal target for viral replication inhibition. First, replication proteases were characterized using a fluorescence resonance energy transfer (FRET) construct by measuring the …

Reversible Inactivation And Desiccation Tolerance Of Silicified Viruses, James R. Laidler, Jessica A. Shugart, Sherry L. Cady, Keith S. Bahjat, Kenneth M. Stedman

Biology Faculty Publications and Presentations

Long-distance host-independent virus dispersal is poorly understood, especially for viruses found in isolated ecosystems. To
demonstrate a possible dispersal mechanism, we show that bacteriophage T4, archaeal virus Sulfolobus spindle-shaped virus Kamchatka, and vaccinia virus are reversibly inactivated by mineralization in silica under conditions similar to volcanic hot
springs. In contrast, bacteriophage PRD1 is not silicified. Moreover, silicification provides viruses with remarkable desiccation
resistance, which could allow extensive aerial dispersal.

Structural Studies On The Rubella Virus Capsid Protein And Its Organization In The Virion, Vidya Mangala Prasad

Open Access Dissertations

Rubella virus is a leading cause of birth defects due to infectious agents. When contracted during pregnancy, rubella infection leads to severe damage in fetuses. Despite its medical importance, very little is known about the structure of the pleomorphic rubella virus as compared to its alphavirus relatives. The rubella capsid protein is a critical structural component of virions as well as a key factor in virus-host interactions. Three crystal structures of the structural domain of the rubella capsid protein have been described here. The polypeptide fold of the capsid protomer has not been observed previously. The capsid protein structure, along …

Endothelial Cell Stimulation Overcomes Restriction And Promotes Productive And Latent Hiv-1 Infection Of Resting Cd4+ T Cells, Anding Shen, Jacob J. Baker, Geoffrey L. Scott, Yelena P. Davis

University Faculty Publications and Creative Works

Highly active antiretroviral therapy (HAART) is able to suppress human immunodeficiency virus type 1 (HIV-1) to undetectable levels in the majority of patients, but eradication has not been achieved because latent viral reservoirs persist, particularly in resting CD4+ T lymphocytes. It is generally understood that HIV-1 does not efficiently infect resting CD4+ T cells, and latent infection in those cells may arise when infected CD4+ T lymphoblasts return to resting state. In this study, we found that stimulation by endothelial cells can render resting CD4+ T cells permissible for direct HIV infection, includingboth productive and latent infection. These stimulated T …

Barrier To Autointegration Factor (Baf) Inhibits Vaccinia Virus Intermediate Transcription In The Absence Of The Viral B1 Kinase, Nouhou Ibrahim, April Wicklund, Augusta Jamin, Matthew S. Wiebe

Nebraska Center for Virology: Faculty Publications

Barrier to autointegration factor (BAF/BANF1) is a cellular DNA-binding protein found in the nucleus and cytoplasm. Cytoplasmic BAF binds to foreign DNA and can act as a defense against vaccinia DNA replication. To evade BAF, vaccinia expresses the B1 kinase, which phosphorylates BAF and blocks its ability to bind DNA. Interestingly, B1 is also needed for viral intermediate gene expression via an unknown mechanism. Therefore, we evaluated the impact of B1-BAF signaling on vaccinia transcription. Strikingly, the decrease in vaccinia transcription caused by loss of B1 can be rescued by depletion of BAF. The repressive action of BAF is greatest …

A Supramolecular Strategy To Assemble Multifunctional Viral Nanoparticles, Limin Chen, Xia Zhao, Yuan Lin, Yubin Huang, Qian Wang

Faculty Publications

Using a one-pot approach driven by the supramolecular interaction between β-cyclodextrin and adamantyl moieties, multifunctional viral nanoparticles can be facilely formulated for biomedical applications.

Hcmv Promotes Breast Cancer Metastasis: Impacts Of Cmvil-10 In The Tumor Microenvironment, Robin Bishop

Master's Theses

Human cytomegalovirus (HCMV) is a highly species-specific, common human pathogen. While a large majority of people are infected with HCMV worldwide, infection is typically asymptomatic in immune competent individuals. To enhance virus persistence and avoid immune detection by the host, HCMV exploits the strategy of encoding homologs of cellular cytokines. One factor produced by HCMV-infected cells is the viral cytokine cmvIL-10, which acts through the cellular IL-10 receptor to induce downstream cell signaling. In instances where HCMV-infected cells infiltrate the tumor microenvironment, the presence of cmvIL-10 in may initiate events that promote a more invasive tumor phenotype. Cancer cells that …

Defining The Requirements For Early Gene Expression In Bacteriophage Hk639, Amanda L. Seaton

Masters Theses & Specialist Projects

Lambdoid phages suppress transcription termination to fully express their genes. Antitermination of early gene expression in most lambdoid phages is mediated by an interaction between the N protein and a number of host-encoded factors. Bacteriophage HK022 does not rely on a protein for antitermination. To promote full expression of early phage genes, the transcripts of the HK022 put sites interact directly with RNA polymerase to convert it to a termination resistant form. Bacteriophage HK639 also uses RNA-mediated antitermination. However, it only possesses a single put-like element in its left operon. Because most lambdoid phages, including HK022, have antiterminator elements in …

Analysis Of Human Papillomavirus Capsid Proteins: Insights Into Capsid Assembly, Willie A. Hughes

School of Biological Sciences: Dissertations, Theses, and Student Research

Papillomaviruses (PVs) are double stranded (ds)-DNA viruses (~8-kbp), which infect mucosal and cutaneous epithelial cells from various mammalian species, causing tumors in both epithelial cell-types. During the late-phase, the capsid proteins (L1 and L2), are expressed to encapsidate the viral genome generating infectious virion particles required for PV. Natural PV infections produce morphologically homogenous progeny virions 55-nm in diameter. Transient transfection systems allow individual expression of the capsid proteins, which are able to produce low-levels of infectious virion-like particles (VLPs) and non-infectious VLPs that have the capacity to resemble and function as wild-type virions.

Results: The research herein demonstrates …

The Role Of Indoleamine 2,3-Dioxygenase In Lp-Bpm5 Murine Retroviral Disease Progression, Megan A. O'Connor, William R. Green

Dartmouth Scholarship

Indoleamine 2,3-dioxygenase (IDO) is an immunomodulatory intracellular enzyme involved in tryptophan degradation. IDO is induced during cancer and microbial infections by cytokines, ligation of co-stimulatory molecules and/or activation of pattern recognition receptors, ultimately leading to modulation of the immune response. LP-BM5 murine retroviral infection induces murine AIDS (MAIDS), which is characterized by profound and broad immunosuppression of T- and B-cell responses. Our lab has previously described multiple mechanisms regulating the development of immunodeficiency of LP-BM5-induced disease, including Programmed Death 1 (PD-1), IL-10, and T-regulatory (Treg) cells. Immunosuppressive roles of IDO have been demonstrated in other retroviral models, suggesting a possible …

Proteomic Studies Of The Influenza Virus-Human Cell Interactions: The Responses Of Host Cell Protein Expression To Viral Infection And The Novel Host Proteins That Interact With Virus Protein Ns1, Yimeng Wang

Graduate Theses and Dissertations

Influenza A viruses (IAVs) continue to be a threat to human health. Despite extensive studies, the mechanisms underlying the IAVs-host interactions during IAV infection remain elusive. We employed quantitative proteomic methods to systematically explore the host cell protein expression responses to IAV infection and examine the function of a critical IAV protein called NS1 by identifying its host binding partners. Specifically, we used a 2-dimentional gel electrophoresis (2-DE) based proteomic method to screen host proteins whose expression was substantially altered by IAV. One critical protein named IκB kinase-gamma (IKKγ) was found to be significantly down-regulated during IAV infection. Functional studies …

Qcm Aptasensor For Rapid And Specific Detection Of Avian Influenza Virus, Luke Brockman

Graduate Theses and Dissertations

There has been a need for rapid detection of avian influenza virus (AIV) H5N1 due to it being a potential pandemic threat. Most of the current methods, including culture isolation and PCR, are very sensitive and specific but require specialized laboratories and trained personnel in order to complete the tests and are time-consuming. The goal of this study was to design a biosensor that would be able to rapidly detect AIV H5N1 using aptamers as biosensing material and a quartz crystal microbalance (QCM) for transducing method. Specific DNA aptamers against AIV H5N1 were immobilized, through biotin and streptavidin conjugation, onto …

In Vitro Characterization Of Avian Influenza Virus Isolates With A Truncated Ns1 Gene Segment, Aaron Dick

Honors Scholar Theses

Avian Influenza Virus represents a significant threat to the world poultry population, and is a potential threat to humans due to the possibility of cross-species AIV infection. Our approach is to characterize a number of avian virus populations with respect to their content of biologically active particles that include hemagglutinating particles (HAP), plaque forming particles (PFP), interferon inducing particles (IFP), interferon induction-suppressing particles (ISP), defective-interfering particles (DIP), cell-killing particles (CKP) and non-infectious cell killing particles (niCKP) using unique in vitro assays developed for avian influenza virus in the Marcus-Sekellick Laboratory. Specifically, we will use a strain of Avian influenza virus, …

A Mathematical Model For Antibiotic Resistance In A Hospital Setting With A Varying Population, Edward H. Snyder

Electronic Theses and Dissertations

Antibiotic-resistant bacteria(ARB) is causing increased health risk and cost to society. Mathematical models have been developed to study the transmission of resistant bacteria and the efficacy of preventive measures to slow its spread within a hospital setting. The majority of these models have assumed a constant total hospital population with the admission and discharge rates being equal throughout the duration. But a typical hospital population varies from day to day and season to season. In this thesis, we apply variable admission and discharge daily rates to existing deterministic and stochastic models which examine the transmission of single and dual resistant …

Evolution Of Human Immunodeficiency Virus Type 1 Clade C Envelope V1–V5 Region During Disease Progression In Non-Human Primate Model, For Yue Tso

School of Biological Sciences: Dissertations, Theses, and Student Research

Human immunodeficiency virus type 1 (HIV-1) clade C strain is the fastest spreading HIV-1 strain globally, especially in Africa. It has been decades since the acquired immune deficiency syndrome (AIDS) pandemic first started. However, an effective anti-HIV-1 vaccine is not yet available, which is partly due to the highly variable nature of HIV-1 envelope gene and the absence of a suitable animal model. Strengthening of the understanding of envelope evolution during disease progression will contribute significantly towards future anti-HIV-1 treatment and preventions.

Non-human primates have been an essential animal model for many biomedical research areas. Using simian-human immunodeficiency virus (SHIV) …

Neuropathogenic Escherichia Coli K1 Does Not Exhibit Proteolytic Activities To Exert Its Pathogenicity, Junaid Iqbal, Mehak Rajan, Ruqaiyyah Siddiqu, Naveed Ahmed Khan

Department of Biological & Biomedical Sciences

Background: Proteases are well-known virulence factors that promote survival, pathogenesis and immune evasion of many pathogens. Several lines of evidence suggest that the blood-brain barrier permeability is a prerequisite in microbial invasion of the central nervous system. Because proteases are frequently associated with vascular permeability by targeting junctional proteins, here it is hypothesized that neuropathogenic Escherichia coli K1 exhibit proteolytic activities to exert its pathogenicity.
Methods: Zymographic assays were performed using collagen and gelatin as substrates. The lysates of whole E. coli K1 strain E44, or E. coli K-12 strain HB101 were tested for proteolytic activities. The conditioned media were …

Telomere-Related Factors And Human Papillomavirus Genome Maintenance, Adam J. Rogers

School of Biological Sciences: Dissertations, Theses, and Student Research

Human papillomaviruses (HPVs) are small DNA tumor viruses identified by their characteristic ability to replicate as a nuclear plasmid in mitotically active basal keratinocytes. A key characteristic of the HPV life cycle is the establishment of a stable maintenance phase wherein the virus replicates at low copy number, which likely occurs in cells expressing little to no E1 and E2. It is thought that HPV16 replicates in a once-per-cell-cycle manner during this portion of its life cycle and presumably interacts with host chromosome replication and maintenance factors to facilitate this replication. The adaptive radiation of papillomaviruses in response to changing …

Enrollment In Yfv Vaccine Trial: An Evaluation Of Recruitment Outcomes Associated With A Randomized Controlled Double-Blind Trial Of A Live Attenuated Yellow Fever Vaccine, Paula M. Frew, Eve T. Shapiro, Lu Lu, Srilatha Edupuganti, Harry L. Keyserling, Mark J. Mulligan

Environmental & Global Health Faculty Research

This investigation evaluated several factors associated with diverse participant enrollment of a clinical trial assessing safety, immunogenicity, and comparative viremia associated with administration of 17-D live, attenuated yellow fever vaccine given alone or in combination with human immune globulin. We obtained baseline participant information (e.g., sociodemographic, medical) and followed recruitment outcomes from 2005 to 2007. Of 355 potential Yellow Fever vaccine study participants, 231 cases were analyzed. Strong interest in study participation was observed among racial and ethnically diverse persons with 36.34% eligible following initial study screening, resulting in 18.75% enrollment. The percentage of white participants increased from 63.66% (prescreened …

Cd4 And Cd8 T Cells Directly Recognize Murine Gammaherpesvirus 68-Immortalized Cells And Prevent Tumor Outgrowth, Xiaozhan Liang, Rebecca L. Crepeau, Weijun Zhang, Samuel H. Speck, Edward J. Usherwood

Dartmouth Scholarship

There has been extensive research regarding T cell recognition of Epstein-Barr virus-transformed cells; however, less is known regarding the recognition of B cells immortalized by gamma-2 herpesviruses. Here we show that B cells immortalized by murine gammaherpesvirus 68 (MHV-68, γHV-68) can be controlled by either CD4 or CD8 T cells in vivo. We present evidence for the direct recognition of infected B cells by CD4 and CD8 T cells. These data will help in the development of immunotherapeutic approaches combating gamma-2 herpesvirus-related disease.