Introduction to Virology

1. Introduction to Virology

2. 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

3. 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?

4. 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

5. X. Viroids • XI. Prions

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

7. II. Historical Perspective • A. Ancient times • 1. poliovirus • 2. smallpox • B. More recent history • 1. 1790’s • Iwanowski • 2. 1890’s • Jenner

8. III. What is a virus? • A. Characteristics

9. B. Comparison to bacteria1. 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

10. 2. Size comparison • 3. Genome size comparison

11. IV. Nucleocapsid morphology • A. Helical • B. Polyhedral • C. Complex

12. V. How viruses multiply (13.10) • A. Basic strategy • Attachment • Penetration • Synthesis of viral proteins and nucleic acids • Maturation • Release

13. B. Bacterial viruses: Fig 13.12 • Lytic vs lysogenic cycle

14. C. Animal Viruses

15. D. Culturing viruses in the lab • 1. bacteriophage • 2. animal viruses

16. VI. How to classify viruses? • A. Formal taxonomies • B. Baltimore classification • C. Which means what?

17. 1. Genome organization

18. 2. Genome organization affects replication

19. 3. DNA Viruses: Life Cycle: Fig 13.17

20. 4. Replication of RNA viruses: Fig 13.17

21. 5. Viral classes • Class I • ds DNA • Class II • ssDNA (positive and negative) • Class III • dsRNA • Class IV • ssRNA (positive)

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

23. Brief note on nomenclature • Family • Genus • Species • eg. Family Herpesviridae, genus Simplexvirus, human herpes virus 2

24. VII. Viruses and the diseases they cause • A. Class I: dsDNA Viruses • 1. Bacterial • 2. Plant

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

26. B. Class II: ssDNA viruses • 1. Bacteria • 2. Plant • 3. Human • A. Parvoviridae

27. C. Class III: dsRNA viruses • 1. Reoviridae

28. D. Class IV: ss (+) RNA viruses • 1. Picornaviridae • 2. Togaviridae • 3. Flaviviridae • 4. Coronaviridae • 5. Calciviridae

29. E. Class V: ss (-) RNA viruses • 1. Rhabdoviridae • 2. Filoviridae • 3. Paramyxoviridae • 4. Orthomyxoviridae • 5. Bunyaviridae

30. Retrovirus Life Cycle: Fig 13.19

31. F. Class VI: ss (+) viruses (dsDNA intermediate) • 1. Retroviridae • Oncoviruses • Lentivirus

32. G. Review of Replication Strategies

33. VIII. Summary of effects of viral infection on cells

34. IX. Oncogenic Viruses

35. X. Viroids

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

37. Prion diseases of humans and animals