WHO Immunological Basis for Immunization Series
Total Page:16
File Type:pdf, Size:1020Kb
Load more
Recommended publications
-
10.2.2 Nomenclature of Viruses and Taxonomic Groups Bacterial Viruses Such As T1, T2 and Φx174
Classification and nomenclature of viruses History of virus classification • Type of host • Type of disease • Transmition by an arthropod vector • Nucleic acid type • SS or DS • Segmented • Size of the virion • Capsid simmetry • Envelope Nomenclature • Small, icosahedral, single-stranded DNA viruses of animals were called parvoviruses (Latin parvus = small) • Nematode-transmitted polyhedral (icosahedral) viruses of plants were called nepoviruses • Phages T2, T4 and T6 were called T even phages • Serological relationships between viruses were investigated • Distinct strains (serotypes) could be distinguished in serological tests • Antisera against purified virions • Serotypes reflect differences in virus proteins International Committee on Taxonomy of Viruses • Order had to be brought • ICTV was formed in 1966 • Many working groups and is advised by virologists around the world • Rules for the nomenclature and classification of viruses • Considers proposals for new taxonomic groups and virus names • Approved are published in book form and on the web Modern virus classification and nomenclature • Each order, family, subfamily and genus is defined by viral characteristics that are necessary for membership of that group. Classification based on genome sequences • Similarity is represented in diagrams known as phylogenetic trees. • Rooted- the tree begins at a root which is assumed to be the ancestor of the viruses in the tree. • Unrooted- no assumption is made about the ancestor of the viruses in the tree. 10.2.2 Nomenclature of viruses and taxonomic groups Bacterial viruses such as T1, T2 and ϕX174. Viruses of humans and other vertebrates diseases that they cause Examples: measles virus, smallpox virus, foot and mouth disease virus Some viruses city, town or river Examples: Newcastle disease virus, Norwalk virus, Ebola virus Insect viruses Many insect viruses were named after the insect, with an indication of the effect of infection on the host. -
Introduction to Viroids and Prions
Harriet Wilson, Lecture Notes Bio. Sci. 4 - Microbiology Sierra College Introduction to Viroids and Prions Viroids – Viroids are plant pathogens made up of short, circular, single-stranded RNA molecules (usually around 246-375 bases in length) that are not surrounded by a protein coat. They have internal base-pairs that cause the formation of folded, three-dimensional, rod-like shapes. Viroids apparently do not code for any polypeptides (proteins), but do cause a variety of disease symptoms in plants. The mechanism for viroid replication is not thoroughly understood, but is apparently dependent on plant enzymes. Some evidence suggests they are related to introns, and that they may also infect animals. Disease processes may involve RNA-interference or activities similar to those involving mi-RNA. Prions – Prions are proteinaceous infectious particles, associated with a number of disease conditions such as Scrapie in sheep, Bovine Spongiform Encephalopathy (BSE) or Mad Cow Disease in cattle, Chronic Wasting Disease (CWD) in wild ungulates such as muledeer and elk, and diseases in humans including Creutzfeld-Jacob disease (CJD), Gerstmann-Straussler-Scheinker syndrome (GSS), Alpers syndrome (in infants), Fatal Familial Insomnia (FFI) and Kuru. These diseases are characterized by loss of motor control, dementia, paralysis, wasting and eventually death. Prions can be transmitted through ingestion, tissue transplantation, and through the use of comtaminated surgical instruments, but can also be transmitted from one generation to the next genetically. This is because prion proteins are encoded by genes normally existing within the brain cells of various animals. Disease is caused by the conversion of normal cell proteins (glycoproteins) into prion proteins. -
Type D Primate Retroviruses: a Review1
[CANCER RESEARCH 38, 3123-3139, October 1978] Type D Primate Retroviruses: A Review1 Donald Fine and Gerald Schochetman Viral Oncology Program, Frederick Cancer Research Center. Frederick, Maryland 21701 Abstract The prototype virus of the type D retroviruses is the techniques. The retrovirus associated with the induction of Mason-Pfizer monkey virus (MPMV). MPMV was originally mammary cancer in mice, MMTV,2 is morphologically dis isolated from a breast carcinoma of a female rhesus tinct from the type C viruses and is the prototype of the type monkey (an Old World monkey). MPMV is of obvious B virus group (30). A retrovirus group of primate origin, importance in that it is the only retrovirus thus far isolated which has properties similar to the type C and type B from a mammary tumor of a primate and has been shown viruses but is morphologically distinct from them, has been to have transforming potential for primate cells in vitro. designated genus Oncornavirus D (30). The prototype virus Subsequent to the isolation of MPMV, viruses morpholog of this genus is the MPMV. MPMV was originally isolated ically and ¡mmunologicallyindistinguishable from MPMV from a mammary carcinoma of a female rhesus monkey (an have been isolated from normal placenta and lactating Old World monkey) (19, 60). Because mammary carcinomas mammary glands of other rhesus monkeys in captivity. represent the most prevalent form of neoplasia in humans Recently, viruses morphologically resembling MPMV have and, furthermore, because the incidence of mammary tu been isolated from a langur monkey (another Old World mors in subhuman primates is rare (61, 62, 70, 78), MPMV monkey) and from squirrel monkeys (a New World mon is of obvious potential importance because it is the only key). -
Basic Properties of Viruses and Virus–Cell Interaction
WBV5 6/27/03 10:28 PM Page 49 Basic Properties of Viruses and Virus–Cell II Interaction PART ✷ VIRUS STRUCTURE AND CLASSIFICATION ✷ CLASSIFICATION SCHEMES ✷ THE BEGINNING AND END OF THE VIRUS REPLICATION CYCLE ✷ LATE EVENTS IN VIRAL INFECTION: CAPSID ASSEMBLY AND VIRION RELEASE ✷ HOST IMMUNE RESPONSE TO VIRAL INFECTION: THE NATURE OF THE VERTEBRATE IMMUNE RESPONSE ✷ PRESENTATION OF VIRAL ANTIGENS TO IMMUNE REACTIVE CELLS ✷ CONTROL AND DYSFUNCTION OF IMMUNITY ✷ MEASUREMENT OF THE IMMUNE REACTION ✷ STRATEGIES TO PROTECT AGAINST AND COMBAT VIRAL INFECTION ✷ VACCINATION — INDUCTION OF IMMUNITY TO PREVENT VIRUS INFECTION ✷ EUKARYOTIC CELL-BASED DEFENSES AGAINST VIRAL REPLICATION ✷ ANTIVIRAL DRUGS ✷ BACTERIAL ANTIVIRAL SYSTEMS — RESTRICTION ENDONUCLEASES ✷ PROBLEMS FOR PART II ✷ ADDITIONAL READING FOR PART II WBV5 6/27/03 10:28 PM Page 50 WBV5 6/27/03 3:35 PM Page 51 Virus Structure and Classification ✷ 5 Viral genomes ✷ Viral capsids ✷ Viral membrane envelopes ✷ CLASSIFICATION SCHEMES CHAPTER ✷ The Baltimore scheme of virus classification ✷ Disease-based classification schemes for viruses ✷ QUESTIONS FOR CHAPTER 5 Viruses are small compared to the wavelength of visible light; indeed, while the largest virus can be discerned in a good light microscope, viruses can only be visualized in detail using an electron microscope. A size scale with some important landmarks is shown in Fig. 5.1. Viruses are composed of a nucleic acid genomeor core, which is the genetic material of the virus, surrounded by a capsid made up of virus-encoded proteins. Viral genetic material encodes the structural proteins of the capsid and other viral proteins essential for other functions in initiating virus replication. The entire structure of the virus (the genome, the capsid, and — where present — the envelope) make up the virion or virus particle. -
A Tool for Hierarchical Clustering, Core Gene Detection and Annotation of (Prokaryotic) Viruses Cristina Moraru
bioRxiv preprint doi: https://doi.org/10.1101/2021.06.14.448304; this version posted June 14, 2021. The copyright holder for this preprint (which was not certified by peer review) is the author/funder. All rights reserved. No reuse allowed without permission. VirClust – a tool for hierarchical clustering, core gene detection and annotation of (prokaryotic) viruses Cristina Moraru Institute for Chemistry and Biology of the Marine Environment, Carl-von-Ossietzky –Str. 9 -11, D-26111 Oldenburg, Germany; [email protected] Abstract Recent years have seen major changes in the classification criteria and taxonomy of viruses. The current classification scheme, also called “megataxonomy of viruses”, recognizes five different viral realms, defined based on the presence of viral hallmark genes. Within the realms, viruses are classified into hierarchical taxons, ideally defined by their shared genes. Therefore, there is currently a need for virus classification tools based on such shared genes / proteins. Here, VirClust is presented – a novel tool capable of performing i) hierarchical clustering of viruses based on intergenomic distances calculated from their protein cluster content, ii) identification of core proteins and iii) annotation of viral proteins. VirClust groups proteins into clusters both based on BLASTP sequence similarity, which identifies more related proteins, and also based on hidden markow models (HMM), which identifies more distantly related proteins. Furthermore, VirClust provides an integrated visualization of the hierarchical clustering tree and of the distribution of the protein content, which allows the identification of the genomic features responsible for the respective clustering. By using different intergenomic distances, the hierarchical trees produced by VirClust can be split into viral genome clusters of different taxonomic ranks. -
Viral Evolution, Morphology, and Classification
Viral Evolution, Morphology, and Classification Discovery and Detection of Viruses Viruses are infectious particles about 100 times smaller than bacteria and can only be observed by electron microscopy. LEARNING OBJECTIVES Describe how viruses were first discovered and how they are detected KEY TAKEAWAYS Key Points • Virions, single virus particles, are 20–250 nanometers in diameter. • In the past, viruses were classified by the type of nucleic acid they contained, DNA or RNA, and whether they had single- or double-stranded nucleic acid. • Molecular analysis of viral replicative cycles is now more routinely used to classify viruses. Key Terms • virus: a submicroscopic infectious organism, now understood to be a non- cellular structure consisting of a core of DNA or RNA surrounded by a protein coat • virion: a single individual particle of a virus (the viral equivalent of a cell) Discovery and Detection The structure of the icosahedral cowpea mosaic virus: In the past, viruses were classified by the type of nucleic acid they contained, DNA or RNA, and whether they had single- or double-stranded nucleic acid. Viruses were first discovered after the development of a porcelain filter, called the Chamberland-Pasteur filter, which could remove all bacteria visible in the microscope from any liquid sample. In 1886, Adolph Meyer demonstrated that a disease of tobacco plants, tobacco mosaic disease, could be transferred from a diseased plant to a healthy one via liquid plant extracts. In 1892, Dmitri Ivanowski showed that this disease could be transmitted in this way even after the Chamberland-Pasteur filter had removed all viable bacteria from the extract. -
Structure Unveils Relationships Between RNA Virus Polymerases
viruses Article Structure Unveils Relationships between RNA Virus Polymerases Heli A. M. Mönttinen † , Janne J. Ravantti * and Minna M. Poranen * Molecular and Integrative Biosciences Research Programme, Faculty of Biological and Environmental Sciences, University of Helsinki, Viikki Biocenter 1, P.O. Box 56 (Viikinkaari 9), 00014 Helsinki, Finland; heli.monttinen@helsinki.fi * Correspondence: janne.ravantti@helsinki.fi (J.J.R.); minna.poranen@helsinki.fi (M.M.P.); Tel.: +358-2941-59110 (M.M.P.) † Present address: Institute of Biotechnology, Helsinki Institute of Life Sciences (HiLIFE), University of Helsinki, Viikki Biocenter 2, P.O. Box 56 (Viikinkaari 5), 00014 Helsinki, Finland. Abstract: RNA viruses are the fastest evolving known biological entities. Consequently, the sequence similarity between homologous viral proteins disappears quickly, limiting the usability of traditional sequence-based phylogenetic methods in the reconstruction of relationships and evolutionary history among RNA viruses. Protein structures, however, typically evolve more slowly than sequences, and structural similarity can still be evident, when no sequence similarity can be detected. Here, we used an automated structural comparison method, homologous structure finder, for comprehensive comparisons of viral RNA-dependent RNA polymerases (RdRps). We identified a common structural core of 231 residues for all the structurally characterized viral RdRps, covering segmented and non-segmented negative-sense, positive-sense, and double-stranded RNA viruses infecting both prokaryotic and eukaryotic hosts. The grouping and branching of the viral RdRps in the structure- based phylogenetic tree follow their functional differentiation. The RdRps using protein primer, RNA primer, or self-priming mechanisms have evolved independently of each other, and the RdRps cluster into two large branches based on the used transcription mechanism. -
Superimposition of Viral Protein Structures: a Means to Decipher the Phylogenies of Viruses
viruses Review Superimposition of Viral Protein Structures: A Means to Decipher the Phylogenies of Viruses Janne J. Ravantti 1 , Ane Martinez-Castillo 2 and Nicola G.A. Abrescia 2,3,4,* 1 Molecular and Integrative Biosciences Research Programme, Faculty of Biological and Environmental Sciences, University of Helsinki, FI-00014 Helsinki, Finland; Janne.Ravantti@helsinki.fi 2 Center for Cooperative Research in Biosciences (CIC bioGUNE), Basque Research and Technology Alliance (BRTA), Bizkaia Technology Park, 48160 Derio, Spain; [email protected] 3 IKERBASQUE, Basque Foundation for Science, 48013 Bilbao, Spain 4 Centro de Investigación Biomédica en Red de Enfermedades Hepáticas y Digestivas (CIBERehd), Instituto de Salud Carlos III, 28029 Madrid, Spain * Correspondence: [email protected]; Tel.: +34-946572502 Received: 10 September 2020; Accepted: 2 October 2020; Published: 9 October 2020 Abstract: Superimposition of protein structures is key in unravelling structural homology across proteins whose sequence similarity is lost. Structural comparison provides insights into protein function and evolution. Here, we review some of the original findings and thoughts that have led to the current established structure-based phylogeny of viruses: starting from the original observation that the major capsid proteins of plant and animal viruses possess similar folds, to the idea that each virus has an innate “self”. This latter idea fueled the conceptualization of the PRD1-adenovirus lineage whose members possess a major capsid protein (innate “self”) with a double jelly roll fold. Based on this approach, long-range viral evolutionary relationships can be detected allowing the virosphere to be classified in four structure-based lineages. However, this process is not without its challenges or limitations. -
Identification of a Ruminant Origin Group B Rotavirus Associated With
viruses Article Identification of a Ruminant Origin Group B Rotavirus Associated with Diarrhea Outbreaks in Foals Tirth Uprety 1,†,‡, Chithra C. Sreenivasan 1,†,‡, Ben M. Hause 2 , Ganwu Li 3, Solomon O. Odemuyiwa 4, Stephan Locke 5,‡, Jocelynn Morgan 5,‡, Li Zeng 5,‡, William F. Gilsenan 6, Nathan Slovis 7, Laurie Metcalfe 6, Craig N. Carter 5,‡, Peter Timoney 1,‡, David Horohov 1,‡, Dan Wang 1,‡ , Erdal Erol 5,*,‡, Emma Adam 1,*,‡ and Feng Li 1,*,‡ 1 Maxwell H. Gluck Equine Research Center, University of Kentucky, Lexington, KY 40546, USA; [email protected] (T.U.); [email protected] (C.C.S.); [email protected] (P.T.); [email protected] (D.H.); [email protected] (D.W.) 2 Department of Veterinary and Biomedical Sciences, South Dakota State University, Brookings, SD 57007, USA; [email protected] 3 Department of Veterinary Diagnostic and Production Animal Medicine, College of Veterinary Medicine, Iowa State University, Ames, IA 50011, USA; [email protected] 4 Veterinary Medical Diagnostic Laboratory, College of Veterinary Medicine, University of Missouri, Columbia, MO 65212, USA; [email protected] 5 Veterinary Diagnostic Laboratory, University of Kentucky, Lexington, KY 40512, USA; [email protected] (S.L.); [email protected] (J.M.); [email protected] (L.Z.); [email protected] (C.N.C.) 6 Rood and Riddle Equine Hospital, Lexington, KY 40511, USA; [email protected] (W.F.G.); [email protected] (L.M.) 7 Hagyard Equine Medical Institute, Lexington, KY 40511, USA; [email protected] * Correspondence: [email protected] (E.E.); [email protected] (E.A.); [email protected] (F.L.) † These authors contributed equally to this work and share first authorship. -
Chapter 21 – Viruses
Chapter 21 | Viruses 559 21 | VIRUSES Figure 21.1 The tobacco mosaic virus, seen here by transmission electron microscopy (left), was the first virus to be discovered. The virus causes disease in tobacco and other plants, such as the orchid (right). (credit a: USDA ARS; credit b: modification of work by USDA Forest Service, Department of Plant Pathology Archive North Carolina State University; scale-bar data from Matt Russell) Chapter Outline 21.1: Viral Evolution, Morphology, and Classification 21.2: Virus Infections and Hosts 21.3: Prevention and Treatment of Viral Infections 21.4: Other Acellular Entities: Prions and Viroids Introduction Viruses are noncellular parasitic entities that cannot be classified within any kingdom. They can infect organisms as diverse as bacteria, plants, and animals. In fact, viruses exist in a sort of netherworld between a living organism and a nonliving entity. Living things grow, metabolize, and reproduce. In contrast, viruses are not cellular, do not have a metabolism or grow, and cannot divide by cell division. Viruses can copy, or replicate themselves; however, they are entirely dependent on resources derived from their host cells to produce progeny viruses—which are assembled in their mature form. No one knows exactly when or how viruses evolved or from what ancestral source because viruses have not left a fossil record. Some virologists contend that modern viruses are a mosaic of bits and pieces of nucleic acids picked up from various sources along their respective evolutionary paths. 21.1 | Viral -
The Reoviridae the VIRUSES
The Reoviridae THE VIRUSES Series Editors HEINZ FRAENKEL-CONRAT, University of California Berkeley, California ROBERT R. WAGNER, University of Virginia School of Medicine Charlottesville, Virginia THE HERPESVIRUSES, Volumes I, 2, 3, and 4 Edited by Bernard Roizman THE REOVIRIDAE Edited by Wolfgang K. Joklik THE PARVOVIRUSES Edited by Kenneth I. Berns The Reoviridae Edited by WOLFGANG K. JOKLIK Duke University Medical Center Durham, North Carolina Springer Science+Business Media, LLC Library of Congress Cataloging in Publication Data Main entry under title: The Reoviridae. (Viruses) Includes bibliographical references and index. 1. Reoviruses. L Joklik, Wolfgang K. II. Series. QR414.R46 1983 576/.64 83-6276 ISBN 978-1-4899-0582-6 ISBN 978-1-4899-0582-6 ISBN 978-1-4899-0580-2 (eBook) DOI 10.1007/978-1-4899-0580-2 © Springer Science+Business Media New York 1983 Originally published by Plenum Press, New York in 1983 Softcover reprint of the hardcover 1st edition 1983 All rights reserved No part of this book may be reproduced, stored in a retrieval system, or transmitted in any form or by any means, electronic, mechanical, photocopying, microfilming, recording, or otherwise, without written permission from the Publisher Con tribu tors Guido 'Boccardo, Istituto di Fitovirologia Applicata del C.N.R., 10135 To rino, Italy Bernard N. Fields, Department of Microbiology and Molecular Genetics, Harvard Medical School, Boston, Massachusetts 02115; and Depart ment of Medicine, Brigham and Women's Hospital, Boston, Massa chusetts 02115 R. I. B. Fran'cki, Department of Plant Pathology, Waite Agricultural Re search Institute, The University of Adelaide, Adelaide 5064, South Australia Barry M. -
Virus Taxonomy
Virus Taxonomy It is the authors’ responsibility to ensure proper application of virus and virus taxon nomenclature. Viruses adheres to the most current international standards of virus taxonomy governed by the International Committee on Taxonomy of Viruses (ICTV). The ICTV oversees the classification of viruses into taxa and the nomenclature of taxa, but not the nomenclature of viruses including their abbreviations. For authors, it is of utmost importance to stringently distinguish in writing between viruses and viral taxa, such as species, genera or families. Viruses are physical entities, whereas taxa (denoted by italicization) are concepts of the mind. Example 1 (virus name and species name differ in spelling): Ebola virus (EBOV) is currently a member of the species Zaire ebolavirus. Ebola virus can infect people; Ebola virions can be concentrated; and new Ebola virus variants can be discovered. Zaire ebolavirus on the other hand cannot be discovered, injected, grown, or vaccinated against; and in contrast to Ebola virus, Zaire ebolavirus does not have a genome. Example 2 (virus name and species name are identical in spelling): measles virus (MeV) is currently a member of the species Measles virus. One can be vaccinated against measles virus, but not against Measles virus. Measles virus may one day be eradicated; Measles virus will not be. As a rule-of-thumb, the use of species names in general virology articles (aside from mentioning to which species a particular virus belongs in an introduction or a method section), and in particular in article titles, is almost always ill-advised. The rules for nomenclature are laid out in the ICTV’s International Code of Virus Classification and Nomenclature (ICVCN; http://www.ictvonline.org/codeOfVirusClassification.asp).