Virology

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Virologydr Jacky Junaedi12The VirusesGeneral CharacteristicsSize, Shape, Classification, Composition (NA, protein, lipid)Infectivity (Host range & tissue tropism) ReplicationPhages vs Animal virusesDNA viruses vs RNA viruses2Definition of a VirusSub microscopic entity consisting of a single nucleic acid surrounded by a protein coat and capable of replication only within the living cells of bacteria, animals or plants. 3What is a virusSub microscopic entities consisting of a single nucleic acid surrounded by a protein coat and capable of replication only within the living cells of bacteria, animals or plants.[1]The key features of this definition are as follows: Single type of nucleic acid either DNA or RNA but not both Replication of the virus only with a living cell they are obligate intracellular parasites.These characteristics are typical for ALL viruses whether they infect bacteria, plants or animals. [1] Adapted from Collins English Dictionary

Definition of a VirusObligateIntracellularParasite4What is a virusSub microscopic entities consisting of a single nucleic acid surrounded by a protein coat and capable of replication only within the living cells of bacteria, animals or plants.[1]The key features of this definition are as follows: Single type of nucleic acid either DNA or RNA but not both Replication of the virus only with a living cell they are obligate intracellular parasites.These characteristics are typical for ALL viruses whether they infect bacteria, plants or animals. [1] Adapted from Collins English Dictionary

5The VirusesGeneral CharacteristicsSize:Shape:Composition:Classification:Infectivity:Host range Tissue tropism

ReplicationPhages vs Animal virusesDNA viruses, RNA virusesPerspective:Size

Virus Shape

(d) Helical

(e) Icosahedral

Viral Diversity andMethods used in Classification

Viral Anatomy

Viral Diversity

Viral Diversity

Viral Diversity

Viral CharacteristicsAcellularInfectiousPhasesExtracellularIntracellularViron structureNucelocapsidCapsidNA+/- Envelope

Viral MorphologySize10-400 nmStructural componentsNucleocapsidEnvelope (+/-)ClassificationsNAss or ds

SizeViral CapsidFunctionProtect NAAids in transfer to hostStructureProtein coatCapsomere arrangeHelicalPolyhedralComplex

Polyhedral Capsids

Capsomeres are capsid subunits

Naked vs. Enveloped Viruses

Viral EnvelopePresenceEnvelopedNaked (non-enveloped)LocationSurrounds capsidSourceHost plasma membraneNuclear membraneEndoplasmic reticulumComponentsPhospholipidProteinsGlycoprotein spikes (+/-)ExamplesInfluenzaRabiesHerpesHIV

Envelope Glycoprotein Spikes

Viral NADNA OR RNAShapeCircularLinearNumberOne Or moreStrandsssds+ or - if RNA

Viral ClassificationdsDNASmall poxHerpesPapillomassDNA ParvodsRNARotavirus+ssRNAPolioRhinoCorona-ssRNAMeasles, mumpsRabiesInfluenzaRetrovirusesHIV

Immune Response

Adaptive ImmunityIMMUNE RESPON28The VirusesGeneral CharacteristicsSize, Shape, Composition (NA, protein, lipid)Classification, Infectivity (Host range & tissue tropism) ReplicationPhages: Lytic vs lysogenic infection, TransductionAnimal viruses: DNA viruses vs RNA viruses, RetrovirusesEffects on CellsCytopathology, Organismal effectsOncogenes and tumorigenesisGeneralPhage Life Cycle

Lytic vsLysogenicCycleTransduction

Transduction

Information Flow in Different Viruses

Replication:A DNA Virus

Replication:An RNA Virus

375 BASIC TYPES OF VIRAL STRUCTURE

HELICALENVELOPED HELICALENVELOPED ICOSAHEDRAL COMPLEX ICOSAHEDRALAdapted from Schaechter et al., Mechanisms of Microbial Disease nucleocapsid icosahedral nucleocapsid nucleocapsid helical nucleocapsid lipid bilayer lipid bilayer glycoprotein spikes= peplomers3738UNCONVENTIONAL AGENTSVIROIDSRNA onlySmall genomeDo not code for proteinSo far, only known viroids are in plants hepatitis delta virus (agent)- some viroid, some virus features3839UNCONVENTIONAL AGENTSPRIONS

protein only?

do not contain any nucleic acid?39