Introduction to Virology

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Introduction to Virology
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Lecture Outline

• I. Objectives
• II. Historical perspective
• III. What is a virus
• A. Characteristics
• B. Comparison to bacteria
• IV. Nucleocapsid morphology
• A. Helical
• B. Polyhedral
• C. Complex

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• V. How viruses multiply
• A. Basic strategy
• B. Bacterial viruses
• C. Animal viruses
• D. Culturing viruses in the lab
• VI. How to classify viruses?
• A. Formal taxonomies
• B. Baltimore Classification
• C. Which means what?

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• VII. Viruses and the diseases they cause
• A. Class I dsDNA
• B. Class II ssDNA
• C. Class III dsRNA
• D. Class IV ss()RNA
• E. Class V ss(-)RNA
• F. Class VI ss()RNA with dsDNA intermediate
• VIII. Summary of effects of viral infection on
  cells
• IX. Oncogenic viruses

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• X. Viroids
• XI. Prions

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I. Objectives

• What is a virus
• How do viruses multiply
• How are viruses classified
• What are some of the diseases viruses cause

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II. Historical Perspective

• A. Ancient times
• 1. poliovirus
• 2. smallpox
• B. More recent history
• 1. 1790s
• Iwanowski
• 2. 1890s
• Jenner

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III. What is a virus?

• A. Characteristics

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B. Comparison to bacteria 1. overall

• 
  Bacteria Virus
• Intracellular parasite (no) yes
• Plasma membrane yes no
• Binary fission yes
  no
• Filterable no
  yes
• Possess DNA RNA yes no
• ATP production yes no
• Ribosomes yes no
• Antibiotic sensitive yes no

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• 2. Size comparison
• 3. Genome size comparison

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IV. Nucleocapsid morphology

• A. Helical
• B. Polyhedral
• C. Complex

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V. How viruses multiply (13.10)

• A. Basic strategy
• Attachment
• Penetration
• Synthesis of viral proteins and nucleic acids
• Maturation
• Release

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B. Bacterial viruses Fig 13.12

• Lytic vs lysogenic cycle

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C. Animal Viruses
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D. Culturing viruses in the lab

• 1. bacteriophage
• 2. animal viruses

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VI. How to classify viruses?

• A. Formal taxonomies
• B. Baltimore classification
• C. Which means what?

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1. Genome organization
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2. Genome organization affects replication
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3. DNA Viruses Life Cycle Fig 13.17
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4. Replication of RNA viruses Fig 13.17
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5. Viral classes

• Class I
• ds DNA
• Class II
• ssDNA (positive and negative)
• Class III
• dsRNA
• Class IV
• ssRNA (positive)

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• Class V
• ssRNA (negative)
• Class VI
• ssRNA (positive, replication intermediate DNA)

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Brief note on nomenclature

• Family
• Genus
• Species
• eg. Family Herpesviridae, genus Simplexvirus,
  human herpes virus 2

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VII. Viruses and the diseases they cause

• A. Class I dsDNA Viruses
• 1. Bacterial
• 2. Plant

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• 3. Human host
• a. Herpesviridae
• b. Adenoviridae
• c. Poxviridae
• d. Papovaviridae
• Papillomavirus
• Polyomavirus
• Vacuolating agent
• e. Hepadnaviridae

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B. Class II ssDNA viruses

• 1. Bacteria
• 2. Plant
• 3. Human
• A. Parvoviridae

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C. Class III dsRNA viruses

• 1. Reoviridae

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D. Class IV ss () RNA viruses

• 1. Picornaviridae
• 2. Togaviridae
• 3. Flaviviridae
• 4. Coronaviridae
• 5. Calciviridae

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E. Class V ss (-) RNA viruses

• 1. Rhabdoviridae
• 2. Filoviridae
• 3. Paramyxoviridae
• 4. Orthomyxoviridae
• 5. Bunyaviridae

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Retrovirus Life Cycle Fig 13.19
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F. Class VI ss () viruses (dsDNA intermediate)

• 1. Retroviridae
• Oncoviruses
• Lentivirus

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G. Review of Replication Strategies
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VIII. Summary of effects of viral infection on
cells
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IX. Oncogenic Viruses
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X. Viroids
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XI. Prions

• A. Fig 13.21
• B. PrPC vs PrPSc
• Structural differences
• Detergent solubility differences
• Differences in susceptibility to protein
  degrading enzymes

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Prion diseases of humans and animals