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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