Download Historical perspectives General characteristics Virus Life Cycle Viral

Historical perspectives
• TMD 1886
• Filterable agent 1892: Ivanowski
• Isolation: 1935 Stanley
Chapter opener 13
General characteristics
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Virus Life Cycle
acellular
Obligate intracellular parasite
No independent metabolism
No independent motility
Infects bacteria, animals and plants
Nucleic acid and protein
• Extracellular: inert, infectious virion
• Intracellular: active, replicating nucleic acid
– Goal is reproduction
Viral structures/terminology
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Virion
Capsid: capsomeres
Nucleic acid
Nucleocapsid
Envelope
Naked vs. enveloped
Table 13.1
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Capsid (capsomeres)
Genetic material of viruses
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dsDNA
ssDNA
dsRNA
ssDNA
Figure 13.1 - Overview
Hosts of viruses
Figure 13.2
Viral sizes
TMV
bacteriophages
Budding influenzae virus
HIV on wbc
Figure 13.3 - Overview
Figure 13.4 - Overview (1 of 4)
Figure 13.4 (2 of 4)
Figure 13.4 (3 of 4)
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Viral shapes
Figure 13.4 (4 of 4)
Figure 13.5 - Overview
helical
Helical capsid
TMV
Figure 13.5a
Polyhedral capsid
Cold virus
icosahedron
http://www.rkm.com.au/VIRUS/Influenza/bird-flu-reassort.html
http://www.rkm.com.au/VIRUS/
Figure 13.5b
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Complex: smallpox
Complex: rabies virus
bullet shaped
Figure 13.5c
Complex virions
Figure 13.5d
bacteriophage
Figure 13.8 - Overview
enveloped
Figure 13.7 - Overview
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Viral Taxonomy
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Nucleic acid type
Morphology: shape, size, envelope
Strategy for replication
Viral species (same genetic info)
Table 13.2 (1 of 2)
Viral LYTIC replication: T4 PHAGE
Table 13.2 (2 of 2)
Figure 13.8 - Overview (1 of 5)
Figure 13.8 (2 of 5)
Figure 13.8 (3 of 5)
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Figure 13.8 (4 of 5)
Figure 13.8 (5 of 5)
Lysogeny (replication):
bacteriophage lambda
Figure 13.9
Figure 13.10
Animal virus replication: entry mechanisms
Example of lysogenic conversion
in bacteria?
Figure 13.11
Figure 13.12 - Overview
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Direct penetration
Membrane fusion
Figure 13.12a, steps 1-3
endocytosis
Figure 13.12b, steps 1-5
Budding of virions from infected cell
Figure 13.12c, steps 1-6
Figure 13.13
Replication strategies
Viruses in cancer
Example?
Figure 13.15 - Overview (1 of 4)
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Embryonated chick eggs
Culturing bacteriophage on
lawn of bacterial cells
Figure 13.16
Figure 13.17
Cell culture
Figure 13.18
Viroids: infectious RNA
Potato spindle tuber viroid: PSTV
Figure 13.19
Figure 13.20
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Sprongiform encephalopathies: sheep
brain scrapie
Prion: proteinacious infective particles
Prion protein: PrP
Figure 13.21
Mad Cow Disease
Figure 13.22
comparisons
UN 13.2
Table 13.5
Discuss Avian Flu threat
UN 13.1
UN 13.3
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