Microbiology Commons^™

Phenotype Of The Triplo-Lethal Locus Of Drosophila Melanogaster And Its Suppression By Hyperoxia, Laura K. Smoyer, Douglas R. Dorer, Kenneth W. Nickerson, Alan C. Christensen

Papers in Microbiology

The Triplo-lethal locus (Tpl) of Drosophila is both triplo-lethal and haploinsufficient, but the function of the locus is unknown. We have examined Tpl-aneuploid embryos and find that, in both trisomics and monosomics, the midgut shows extensive cell death and the tracheae are abnormal. Shortly thereafter, all tissues die. PCR-based genotyping of individual embryos and larvae show that this phenotype occurs in the trisomics after hatching and in the monosomics before hatching. Weak alleles of the interacting gene Su(Tpl) delay the death of Tpl trisomics, but they still show the same tracheal and midgut phenotypes before dying. Hyperoxia (45% oxygen) …

The Endocrine Regulation Of Wing Polymorphism In Insects: State Of The Art, Recent Surprises, And Future Directions, Anthony J. Zera

Anthony Zera Publications

The endocrine mechanisms controlling the development and reproduction of flight-capable (long-winged) and flightless (short-winged or wingless) morphs of wing-polymorphic insects have been intensively investigated. The "classical model," put forward in the early 1960s, postulates that morph-specific differences in development and reproduction are caused by variation in the titers of juvenile hormone (JH) and/or ecdysone. Despite decades of study, the importance of these hormones in regulating wing polymorphism in aphids and planthoppers remains uncertain. This uncertainly is largely a consequence of technical and size constraints which have severely limited the types of endocrine approaches that can be used in these insects. …

Subpopulations Of Equine Infectious Anemia Virus Rev Coexist In Vivo And Differ In Phenotype, Prasith Baccam, Robert J. Thompson, Yuxing Li, Wendy O. Sparks, Michael Belshan, Karin S. Dorman, Yvonne Wannemuehler, J. Lindsay Oaks, James L. Cornette, Susan Carpenter

Nebraska Center for Virology: Faculty Publications

Lentiviruses exist in vivo as a population of related, nonidentical genotypes, commonly referred to as quasispecies. The quasispecies structure is characteristic of complex adaptive systems and contributes to the high rate of evolution in lentiviruses that confounds efforts to develop effective vaccines and antiviral therapies. Here, we describe analyses of genetic data from longitudinal studies of genetic variation in a lentivirus regulatory protein, Rev, over the course of disease in ponies experimentally infected with equine infectious anemia virus. As observed with other lentivirus data, the Rev variants exhibited a quasispecies character. Phylogenetic and partition analyses suggested that the Rev quasispecies …

Tomographic Reconstruction Of Treponemal Cytoplasmic Filaments Reveals Novel Bridging And Anchoring Components, Jacques Izard, Bruce F. Mcewen, Rita M. Barnard, Thomas Portuese, William A. Samsonoff, Ronald J. Limberger

Department of Food Science and Technology: Faculty Publications

An understanding of the involvement of bacterial cytoplasmic filaments in cell division requires the elucidation of the structural organization of those filamentous structures. Treponemal cytoplasmic filaments are composed of one protein, CfpA, and have been demonstrated to be involved in cell division. In this study, we used electron tomography to show that the filaments are part of a complex with a novel molecular organization that includes at least two distinct features decorating the filaments. One set of components appears to anchor the filaments to the cytoplasmic membrane. The other set of components appears to bridge the cytoplasmic filaments on the …

Genome Of Bovine Herpesvirus 5, Gustavo A. Delhon, M. P. Moraes, Z. Lu, C. L. Afonso, E. F. Flores, R. Weiblen, G. F. Kutish, D. L. Rock

Nebraska Center for Virology: Faculty Publications

Here we present the complete genomic sequence of bovine herpesvirus 5 (BHV-5), an alphaherpesvirus responsible for fatal meningoencephalitis in cattle. The 138,390-bp genome encodes 70 putative proteins and resembles the α2 subgroup of herpesviruses in genomic organization and gene content. BHV-5 is very similar to BHV-1, the etiological agent of infectious bovine rhinotracheitis, as reflected by the high level of amino acid identity in their protein repertoires (average, 82%). The highest similarity to BHV-1 products (≥95% amino acid identity) is found in proteins involved in viral DNA replication and processing (UL5, UL15, UL29, and UL39) and in virion proteins (UL14, …

Morph-Dependent Fatty Acid Oxidation In A Wing-Polymorphic Cricket: Implications For The Trade-Off Between Dispersal And Reproduction, Anthony J. Zera, Zhangwu Zhao

Anthony Zera Publications

Although a considerable amount of information is available on the ecology and physiology of wing polymorphism, much less is known about the biochemical–genetic basis of morph specialization for dispersal versus reproduction. Previous studies have shown that the dispersing morph of the wing-polymorphic cricket, Gryllus firmus, prioritizes the accumulation of triglyceride flight fuel over ovarian growth, while the opposite occurs in the flightless morph during the first week of adulthood. In this study, we compared the in vivo rate of lipid oxidation between genetic stocks of flight-capable versus flightless morphs to determine the role of lipid catabolism in morph specialization …

Bovine Herpes Virus Gd Protein Produced In Plants Using A Recombinant Tobacco Mosaic Virus (Tmv) Vector Possesses Authentic Antigenicity, D. M. Pérez Filgueira, P.I. Zamorano, M. G. Dominguez, O. Taboga, M. P. Del Medico Zajac, M. Puntel, S. A. Romera, Thomas Jack Morris, M. V. Borca, A. M. Sadir

Papers in Virology

A tobacco mosaic virus (TMV)-based vector was utilized for expression of a cytosolic form of the bovine herpesvirus type 1 (BHV-1) protein glycoprotein D (gDc). Nicotiana benthamiana plants were harvested 7 days after inoculation with RNA transcripts derived from the TMV-gDc recombinant virus. Recombinant gDc protein of expected electrophoretic mobility accumulated in inoculated leaves to a concentration of about 20 μg/g of fresh leaf tissue. Oil-based vaccines were formulated with crude foliar extracts to immunize mice parentally. After a single injection, animals developed a sustained and specific response to both the isolated gD and native virus particles. Cattle vaccinated with …

Quorum Sensing In Candida Albicans: Probing Farnesol’S Mode Of Action With 40 Natural And Synthetic Farnesol Analogs, Roman Shchepin, Jacob M. Hornby, Erin Burger, Timothy Niessen, Patrick H. Dussault, Kenneth Nickerson

Kenneth Nickerson Papers

The dimorphic fungus Candida albicans produces extracellular farnesol (3,7, 11-trimethyl-2,6,10-dodecatriene- 1-ol) which acts as a quorum-sensing molecule (QSM) to suppress filamentation. Of four possible geometric isomers of farnesol, only the E,E isomer possesses QSM activity. We tested 40 natural and synthetic analogs of farnesol for their activity in an N-acetylglucosamine-induced differentiation assay for germ tube formation (GTF). Modified structural features include the head group, chain length, presence or absence of the three double bonds, substitution of a backbone carbon by S, O, N, and Se heteroatoms, presence or absence of a 3-methyl branch, and the bulkiness of the hydrophobic …

To The Editor: Reply To Sarmati, Brad P. Brayfield, John T. West, Charles D. Mitchell, Charles Wood

Nebraska Center for Virology: Faculty Publications

The letter by Sarmati et al. [1] presents data indicating that they were unable to find a significant correlation between human herpesvirus (HHV)–8 seropositivity and a history of spontaneous abortion in a group of 245 human immunodeficiency virus (HIV) type 1–seronegative women but that they did observe a correlation between high HHV-8 antibody titers (≥1:1280) and spontaneous abortion. Although it is possible that an increased risk of spontaneous abortion may be associated with active infection with HHV-8, at this point there is not enough evidence to support such an association. Given that several human herpes viruses are well-known agents of …

Farnesol Biosynthesis In Candida Albicans: Cellular Response To Sterol Inhibition By Zaragozic Acid B, Jacob M. Hornby, Bessie W. Kebaara, Kenneth W. Nickerson

Papers in Microbiology

The dimorphic fungus Candida albicans produces farnesol as a quorum-sensing molecule that regulates cellular morphology. The biosynthetic origin of farnesol has been resolved by treating these cells with zaragozic acid B, a potent inhibitor of squalene synthase in the sterol biosynthetic pathway. Treatment with zaragozic acid B leads to an eightfold increase in the amount of farnesol produced by C. albicans. Furthermore, C. albicans cell extracts contain enzymatic activity to convert [³H]farnesyl pyrophosphate to [³H]farnesol. Many common antifungal antibiotics (e.g., zaragozic acids, azoles, and allylamines) target steps in sterol biosynthesis. We suggest that the fungicidal …

Identification Of The Nuclear Localization Signal Of Human Immunodeficiency Virus Type 2 Vpx, Michael Belshan, Lee Ratner

Nebraska Center for Virology: Faculty Publications

The Vpx protein of human immunodeficiency virus type 2 (HIV-2) is a viral accessory protein related to, but distinct from, the Vpr protein of HIV-1. Vpx is packaged into virions and, as a component of the viral preintegration complex (PIC), Vpx is required for efficient virus replication in nondividing cells. Therefore, the localization of Vpx in cells is dynamic and dependent upon discrete domains of the protein. Expressed in the absence of other viral proteins, Vpx localizes to the nucleus of cells. However, if expressed with the Gag protein of HIV-2, Vpx localizes to the plasma membrane of cells. To …

Life-History Evolution And The Microevolution Of Intermediary Metabolism: Activities Of Lipid-Metabolizing Enzymes In Life-History Morphs Of A Wing-Dimorphic Cricket, Anthony J. Zera, Zhangwu Zhao

Anthony Zera Publications

Although a considerable amount of information is available on the ecology, genetics, and physiology of life-history traits, much more limited data are available on the biochemical and genetic correlates of life-history variation within species. Specific activities of five enzymes of lipid biosynthesis and two enzymes of amino acid catabolism were compared among lines selected for flight-capable (LW[f]) versus flightless (SW) morphs of the cricket Gryllus firmus. These morphs, which exist in natural populations, differ genetically in ovarian growth (100–400% higher in SW) and aspects of flight capability including the size of wings and flight muscles, and the concentration of triglyceride …

Postnatal Human Herpesvirus 8 And Human Immunodeficiency Virus Type 1 Infection In Mothers And Infants From Zambia, Brad P. Brayfield, Saul Phiri, Chipepo Kankasa, Jubra Muyanga, Hamakwa Mantina, Geoffrey Kwenda, John T. West, Ganapati Bhat, Dave B. Marx, Winslow Klaskala, Charles D. Mitchell, Charles Wood

Nebraska Center for Virology: Faculty Publications

The specific route and timing of human herpesvirus (HHV) 8 infection in regions where Kaposi sarcoma is endemic are not known. HHV-8 infection and any risk factors that may be associated with HHV-8, including human immunodeficiency virus (HIV) type 1 infection, were monitored during the 12-month post-delivery period for 416 mothers and 485 infants from Lusaka, Zambia. HHV-8 incident infection rates during this period were 3.2 and 5.3 infections/100 person-years for infants and mothers, respectively. HHV-8 infection among infants was not associated with HHV-8 or HIV-1 infection in the mother. Among the HHV-8–positive infants, 2 of 12 tested were found …

Rapid Prion Neuroinvasion Following Tongue Infection, Jason C. Bartz, Anthony E. Kincaid, Richard A. Bessen

Nebraska Center for Virology: Faculty Publications

Food-borne transmission of prions can lead to infection of the gastrointestinal tract and neuroinvasion via the splanchnic and vagus nerves. Here we report that the transmission of transmissible mink encephalopathy (TME) is 100,000-fold more efficient by inoculation of prions into the tongues of hamsters than by oral ingestion. The incubation period following TME agent (hereinafter referred to as TME) inoculation into the lingual muscles was the shortest among the five nonneuronal routes of inoculation, including another intramuscular route. Deposition of the abnormal isoform of the prion protein, PrP^Sc, was first detected in the tongue and submandibular lymph node …

Structural Analyses Of Phycodnaviridae And Iridoviridae, Alan A. Simpson, Narayanasamy Nandhagopal, James L. Van Etten, Michael G. Rossmann

Nebraska Center for Virology: Faculty Publications

The Phycodnaviridae, Iridoviridae and related viruses, with diameters of 1500±2000 A Ê , are formed from large trigonal arrays of hexagonally close-packed capsomers forming the faces of icosahedra [Yan et al. (2000), Nature Struct. Biol. 7, 101-103; Nandhagopal et al. (2002), Proc. Natl Acad. Sci. USA, 99, 14758-14763]. Caspar and Klug predicted that such structures could be assembled from hexameric capsomers [Caspar & Klug (1962), Cold Spring Harbor. Symp. Quant. Biol. 27, 1-24], as was subsequently found in numerous icosahedral viruses. During the course of evolution, some viruses, including the virus families …

Functional Implications In Apoptosis By Interferon Inducible Gene Product 1-8d, The Binding Protein To Adenovirus Preterminal Protein, Insil Joung, Peter C. Angeletti, Jeffrey A. Engler

Nebraska Center for Virology: Faculty Publications

Adenovirus (Ad) precursor to the terminal protein (pTP) plays an essential roles in the viral DNA

replication. Ad pTP serves as a primer for the synthesis of a new DNA strand during the initiation

step of replication. In addition, Ad pTP forms organized spherical replication foci on the nuclear

matrix (NM) and anchors the viral genome to the NM. Here we identified the interferon inducible

gene product 1-8D (Inid) as a pTP binding protein by using a two-hybrid screen of a HeLa cDNA

library. Of the clones obtained in this assay, nine were identical to the Inid, a 13-kDa polypeptide …

Potentiation Of Trail-Induced Apoptosis In Primary Effusion Lymphoma Through Azidothymidine-Mediated Inhibition Of Nf-[Kappa]B, Subrata K. Ghosh, Charles Wood, Lawrence H. Boise, Abdul M. Mian, Vadim V. Deyev, Gerold Feuer, Ngoc L. Toomey, Nicole C. Shank, Lisa Cabral, Glen N. Barber, William J. Harrington

Nebraska Center for Virology: Faculty Publications

The survival of viral mediated lymphomas depends upon constitutive nuclear factor kappa B (NF-[kappa]B) activity. AIDS-related human herpesvirus type 8–associated primary effusion lymphoma (PEL) responds poorly to chemotherapy and is almost invariably fatal. We have previously demonstrated that the antiviral combination of interferon alpha (IFN-[alpha]) and azidothymidine (AZT) induces apoptosis in PEL cell lines. We therefore used these agents as therapy for an AIDS patient with PEL. The patient had a dramatic response, with complete resolution of his malignant effusion in 5 days. In PEL cells, the death receptor ligand known as tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) is markedly …

Epitope Mapping And Characterization Of A Novel Cd4-Induced Human Monoclonal Antibody Capable Of Neutralizing Primary Hiv-1 Strains, Shi-Hua Xiang, Liping Wang, Mariam Abreu, Chih-Chin Huang, Peter D. Kwong, Eric Rosenberg, James E. Robinson, Joseph Sodroski

Nebraska Center for Virology: Faculty Publications

Human immunodeficiency virus (HIV-1) enters target cells by binding its gp120 exterior envelope glycoprotein to CD4 and one of the chemokine receptors, CCR5 or CXCR4. CD4-induced (CD4i) antibodies bind gp120 more efficiently after CD4 binding and block the interaction with the chemokine receptor. Examples of CD4i antibodies are limited, and the prototypes of the CD4i antibodies exhibit only weak neutralizing activity against primary, clinical HIV-1 isolates. Here we report the identification of a novel antibody, E51, that exhibits CD4-induced binding to gp120 and neutralizes primary HIV-1 more efficiently than the prototypic CD4i antibodies. The E51 antibody blocks the interaction of …

Animal Anti-Apoptotic Genes Ameliorate The Loss Of Turgor In Water-Stressed Transgenic Tobacco, Tala Awada, D. D. Dunigan, M. B. Dickman

Nebraska Center for Virology: Faculty Publications

Nicotiana tabacum L. ‘Glurk’ plants were transformed with antiapoptotic animal genes [chicken Bcl-xl; nematode CED-9; chicken Bcl-xl(GA) a mutant of Bcl-xl; and a 3’ non-coding region of human Bcl-2, referred to as 161-1]. Our objectives were to determine whether plant transformation with anti-apoptotic genes ameliorates drought tolerance in tobacco plants by subjecting the plants to a dry-down period. The non-transformed Glurk and the transgenic Glurk harboring G115, which expresses β-glucuronidase, served as controls. Transformation of tobacco plants with animal anti-apoptotic genes significantly impacted the rates of photosynthesis (A) and stomatal conductance (g_s), but not to the same extent …

Identification Of Novel Domains Within Sox-2 And Sox-11 Involved In Autoinhibition Of Dna Binding And Partnership Specificity, Matthew S. Wiebe, Tamara K. Nowling, Angie Rizzino

Nebraska Center for Virology: Faculty Publications

Sox transcription factors play key regulatory roles throughout development, binding DNA through a consensus (A/T)(A/T)CAA(A/T)G sequence. Although many different Sox proteins bind to this se-quence, it has been observed that gene regulatory elements are commonly responsive to only a small subset of the entire family, implying that regulatory mechanisms exist to permit selective DNA bind-ing and/or transactivation by Sox family members. To identify and explore the mechanisms modu-lating gene activation by Sox proteins further, we compared the function of Sox-2 and Sox-11. This led to the discovery that Sox proteins are regulated differentially at multiple levels, including trans-activation, protein partnerships …

Duration Of Infection And Proportion Of Pigs Persistently Infected With Porcine Reproductive And Respiratory Syndrome Virus, Robert W. Wills, Alan R. Doster, Judith A. Galeota, Jung-Hyang Sur, Fernando A. Osorio

Nebraska Center for Virology: Faculty Publications

Understanding the dynamics of porcine reproductive and respiratory syndrome virus (PRRSV) persistence in individual pigs is essential to the development of successful control programs. The objectives of this study were to investigate the proportion of inoculated pigs that become persistently infected with PRRSV and the duration of their infection. Additionally, different diagnostic techniques that detect persistent infections were compared. Twenty-eight 35-day-old pigs were inoculated with PRRSV. Serum and tonsil biopsy samples were collected on days 0, 7, 14, and 28 and then approximately monthly thereafter until day 251 post-inoculation (p.i.). Tonsil, lymph node, and lung samples were collected following euthanasia …

The Coat Protein Of Turnip Crinkle Virus Suppresses Posttranscriptional Gene Silencing At An Early Initiation Step, Feng Qu, Tao Ren, Thomas Jack Morris

Nebraska Center for Virology: Faculty Publications

Posttranscriptional gene silencing (PTGS), or RNA silencing, is a sequence-specific RNA degradation process that targets foreign RNA, including viral and transposon RNA for destruction. Several RNA plant viruses have been shown to encode suppressors of PTGS in order to survive this host defense. We report here that the coat protein (CP) of Turnip crinkle virus (TCV) strongly suppresses PTGS. The Agrobacterium infiltration system was used to demonstrate that TCV CP suppressed the local PTGS as strongly as several previously reported virus-coded suppressors and that the action of TCV CP eliminated the small interfering RNAs associated with PTGS. We have also …

Eight Gram-Negative Bacteria Are 10,000 Times More Sensitive To Cationic Detergents Than To Anionic Detergents, Soumitra Rajagopal, Nicole Eis, Kenneth Nickerson

Kenneth Nickerson Papers

In liquid culture, eight typical Gram-negative bacteria were ca. 10,000-fold more sensitive to cationic detergents than to the anionic detergent sodium dodecyl sulfate. Cetyltrimethylammonium bromide (CTAB) was inhibitory at concentrations ranging from 0.0006% to 0.01%. Four pseudomonads able to form biofilms were ca. 1000-fold more resistant to CTAB on Luria–Bertani agar plates than they were in liquid culture. A lasI mutant of Pseudomonas aeruginosa was only able to tolerate 0.1% CTAB on Luria–Bertani agar plates but could tolerate 5% CTAB when supplemented with homoserine lactone containing culture supernatants.

En culture liquide, huit bactéries Gram négatif typiques étaient ca. 10,000 fois …

Differential Lipid Biosynthesis Underlies A Tradeoff Between Reproduction And Fl Ight Capability In A Wing-Polymorphic Cricket, Zhangwu Zhao, Anthony J. Zera

Anthony Zera Publications

The biochemical basis of life-history tradeoffs is a poorly studied aspect of life-history evolution. We used radiotracer and endocrine approaches to investigate the extent to which morphs of a wing-polymorphic insect differ in the biosynthesis of lipid classes important for dispersal capability vs. reproduction (ovarian growth). The flightcapable genotype of Gryllus firmus biosynthesized a greater amount of total lipid and triglyceride (main flight fuel), which was preferentially allocated to somatic tissue during early adulthood. By contrast, the fl ightless genotype biosynthesized a significantly greater amount of phospholipid (important in egg development), which was preferentially allocated to ovaries. Topical application of …

The Structure And Evolution Of The Major Capsid Protein Of A Large, Lipid-Containing Dna Virus, Narayanasamy Nandhagopal, Alan Simpson, James Gurnon, Xiadong Yan, Timothy Baker, Michael V. Graves, James L. Van Etten, Michael Rossman

Nebraska Center for Virology: Faculty Publications

Paramecium bursaria Chlorella virus type 1 (PBCV-1) is a very large, icosahedral virus containing an internal membrane enclosed within a glycoprotein coat consisting of pseudohexagonal arrays of trimeric capsomers. Each capsomer is composed of three molecules of the major capsid protein, Vp54, the 2.0-Å resolution structure of which is reported here. Four N-linked and two O-linked glycosylation sites were identified. The N-linked sites are associated with nonstandard amino acid motifs as a result of glycosylation by virus-encoded enzymes. Each monomer of the trimeric structure consists of two eight-stranded, antiparallel β-barrel, “jelly-roll” domains related by a pseudo-sixfold rotation. The fold of …

Unique Epitope Of Bovine Immunodeficiency Virus Gag Protein Spans The Cleavage Site Between P16Ma And P2l, Ming Lu, Ling Zheng, Kathy Mitchell, Sanjay Kapil, Charles Wood, Harish Minocha

Nebraska Center for Virology: Faculty Publications

Bovine immunodeficiency virus (BIV) and Jembrana disease virus (JDV) are closely related bovine lentiviruses that are difficult to distinguish by presently available diagnostic methods. Recently, in our laboratory, a monoclonal antibody (MAb; MAb 10H1) against the BIV Gag protein identified a differential epitope, located at the 6.4-kDa N terminus of a 29-kDa Gag capsid protein, which was absent in JDV. To define the essential amino acids of the epitope, a series of primers within the 163 bp of DNA corresponding to the 6.4-kDa protein were designed. The full-length 163-bp DNA fragment and the smaller DNA fragments with deletions were amplified …

Review Of Dispersal. Based On A Conference Held In Roscoff, France, 23 April–1 May 1999., Anthony J. Zera

Anthony Zera Publications

Edited by Jean Clobert, Etienne Danchin, André A Dhondt, and James D Nichols. Oxford and New York: Oxford University Press.

Dispersal is a phenomenon of central importance in ecology and evolution. Yet many of its fundamental aspects remain poorly understood or barely investigated. This excellent, broad-ranging volume is a collection of 26 short reviews derived from a Centre National de la Recherche (CNRS)-National Science Foundation (NSF) sponsored workshop held in 1999. As stated by the editors, this book is mainly comprised of “reviews and more theoretical approaches, with a limited number of empirical examples” (p. xx) on dispersal.

I highly …

Sodium Dodecyl Sulfate Hypersensitivity Of Clpp And Clpb Mutants Of Escherichia Coli, Soumitra Rajagopal, Narasimhan Sudarsan, Kenneth W. Nickerson

Papers in Microbiology

We studied the hypersensitivity of clpP and clpB mutants of Escherichia coli to sodium dodecyl sulfate (SDS). Both wild-type E. coli MC4100 and lon mutants grew in the presence of 10% SDS, whereas isogenic clpP and clpB single mutants could not grow above 0.5% SDS and clpA and clpX single mutants could not grow above 5.0% SDS. For wild-type E. coli, cellular ClpP levels as determined by Western immunoblot analysis increased ca. sixfold as the levels of added SDS increased from 0 to 2%. Capsular colanic acid, measured as uronic acid, increased ca. sixfold as the levels of added …

Retrograde Transport Of Transmissible Mink Encephalopathy Within Descending Motor Tracts, Jason C. Bartz, Anthony E. Kincaid, Richard A. Bessen

Nebraska Center for Virology: Faculty Publications

The spread of the abnormal conformation of the prion protein, PrP^Sc, within the spinal cord is central to the pathogenesis of transmissible prion diseases, but the mechanism of transport has not been determined. For this report, the route of transport of the HY strain of transmissible mink encephalopathy (TME), a prion disease of mink, in the central nervous system following unilateral inoculation into the sciatic nerves of Syrian hamsters was investigated. PrP^Sc was detected at 3 weeks postinfection in the lumbar spinal cord and ascended to the brain at a rate of approximately 3.3 mm per day. …

Ornithine Decarboxylase Encoded By Chlorella Virus Pbcv-1, Tiara A. Morehead, James R. Gurnon, Byron Adams, Kenneth Nickerson, Lisa A. Fitzgerald, James L. Van Etten

Nebraska Center for Virology: Faculty Publications

Sequence analysis of the 330-kb genome of chlorella virus PBCV-1 revealed an open reading frame, A207R, which encodes a protein with 37–41% amino acid identity to ornithine decarboxylase (ODC) from many eukaryotic organisms. The a207r gene was cloned and the protein was expressed as a His-A207R fusion protein in Escherichia coli. The recombinant protein catalyzes pyridoxal 5’-phosphate-dependent decarboxylation of ornithine to putrescine, the first step in the polyamine biosynthetic pathway The enzyme has a pH optimum of 9.0 and a temperature optimum of 42°C, and it requires dithiothreitol for maximal activity. The enzyme has a Km, for ornithine of …