Viruses

1. Viruses • Individual Viruses = Virion • Not cells – nonliving • Size 0.02 -0.3 μm • Bacterial Viruses = Bacteriophage T 4

2. Viral Genome • Double Strand or Single Strand • DNA or RNA • Most Genomes Linear • Overlapping genes Human Papillomavirus

3. Protein Coat • Capsid, Coat, Shell • Capsomer - Individual Proteins • Self Assembly • Nucleocapsid

4. Viral Symmetry • Helical • Icosahedral 20 faces, 12 vertices

5. Icosahedral Subunits

6. Tobacco Mosaic Virus Herpes Simplex Virus

7. Enveloped Virus

8. Complex Virus T 4 Bacteriophage

9. Enzymes in Viruses • Reverse Transcriptase • Lysozyme • RNA Polymerase • Neuraminidase

10. Viral Host • Living Cells • Animal Host • Cell Culture • Tissue Culture • Monolayer

11. Cell Line • Primary Culture Line • Transformation • Viruses • Mutagen • Permanent Cell line • HELA –Henrietta Lacks

12. Quantification of Viruses • Plaque Assay – Bacteria • Efficiency of Plating • Animal Infectivity Methods • End Point Dilution

13. Bacteriophage Plaques

14. Plaques in Tissue Culture Monolayer

15. Viral Replication • Attachment • Penetration

17. Synthesis 1. Production of Early Proteins Replication of Nucleic Acids 2. Production of Late Proteins Viral Coat

18. Assembly • Release

19. One-step Growth Curve Latent Period

20. Some Host Cells Use Restriction Enzymes to Destroy DNA Viruses • Some Viruses Can Modify Their Genome’s Restriction Sites for Protection

21. Baltimore Classification Scheme David Baltimore, Howard Temin, Renato Dulbecco 1975 Reverse transciptase Retro virus 6 Classes based on DNA→RNA→Protein 7th Class Hepadnaviruses added

22. 6 Classes of Viruses Class I DS DNA Herpes virus Class II SS DNA ØX 174 Class III DS RNA Reovirus –rotavirus Class IV +SS RNA Polio Class V -SS RNA Influenza Class VI SS RNA Retrovirus Others?

23. HEPADNAVIRUS Class VII DS DNA virus Reverse transcriptase Use RNA intermediate Smallest genome 3-4 kb Hepatitis B

24. +/- SS RNA Viruses SS DNA Viruses DS Intermediates Reverse Transcriptase

25. Virulent Bacteriophage • Lytic T Phages • T4, T7 DS DNA • Head, Tail, Spikes Base Plate, Tail Fibers, Contractile Sheath • Hydroxymethyl-cytosine

26. Lambda • Best Known Virus? • Can be Virulent or Temperate • Lysis or Lysogeny • Becomes Prophage (Provirus) • Gives Immunity to Host • Specific Insertion Site

28. Maintenance of Lysogeny • Lambda Repressor -Lysogeny • CRO Protein - Lysis • Induction

29. Animal Viruses DNA Viruses RNA Viruses

30. Eukaryotic Host Types of Infections: Lytic Persistent Latent Hepatitis A Herpes

31. Transformation Neoplasm Benign Malignant Metastasis Oncogene Cancer Viruses

32. Retrovirus • RNA Genome • Reverse Transcriptase • DNA Copy Insert into Host Genome • AIDS • Acquired Immunodeficiency Syndrome • HIV – Human Immunodeficiency Virus HIV

33. Subviral Entities • Defective Viruses • Parasitic? • Helper Viruses • Satellite Viruses • AAV – Adenovirus Associated Virus • Specific Insertion Sites

34. Viroids • Naked Circles • SS RNA • 246-375 Nucleotides • Plant Diseases • Regulatory RNA • -sRNA

35. Prions • Infectious Proteins? • Chaperone Protein • Kuru • Mad Cow Disease • Scrapies • Creutzfeldt- Jakob Disease

36. Prion Infectious Cycle • PrPc → PrPsc • Infectious, • Sporadic, or • Inherited Prion Disease • Mice with no PrPc are Normal?

37. Viruses Word List

38. Viruses 2

39. Viruses 3

40. Viruses 4

41. Viruses 5

42. Viruses 6

43. Viruses 7

44. Viruses 8