Viruses Individual Viruses Virion Not cells nonliving Size

Viruses • Individual Viruses = Virion • Not cells – nonliving • Size 0. 02 -0. 3 μm • Bacterial Viruses = Bacteriophage T 4

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

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

Viral Symmetry • Icosahedral 20 faces, 12 vertices • Helical

Icosahedral Subunits

Herpes Simplex Virus Tobacco Mosaic Virus

Enveloped Virus

Complex Virus T 4 Bacteriophage

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

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

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

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

Bacteriophage Plaques

Plaques in Tissue Culture Monolayer

Viral Replication • Attachment • Penetration

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

• Assembly • Release

One-step Growth Curve Latent Period

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

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

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

Virulent Bacteriophage • Lytic T Phages • T 4, T 7 DS DNA • Head, Tail, Spikes Base Plate, Tail Fibers, Contractile Sheath • Hydroxymethylcytosine

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

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

Animal Viruses DNA Viruses RNA Viruses

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

Cancer Viruses • Transformation • Neoplasm • Benign • Malignant • Metastasis • Oncogene

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

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

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

Prions • • • Infectious Proteins? Chaperone Protein Kuru Mad Cow Disease Scrapies Creutzfeldt. Jakob Disease 10/23/2021

Prion Infectious Cycle • • • Pr. Pc → Pr. Psc Infectious, Sporadic, or Inherited Prion Disease Mice with no Pr. Pc are Normal?

Viruses Word List Virion Bacteriophage 28 – 200 nm (0. 2 μm) Genome SS/DS RNA/DNA Capsid, Coat, Shell Capsomer Self-Assembly Nucleocapsid Viral Symmetry Helical Icosahedral Enveloped Viruses Complex Viruses Enzymes in Virion Reverse Transcriptase Lysozyme Viral Host Living Organisms Cell (Tissue) Culture Monolayer Primary Culture Line

Viruses 2 Transformation Permanent Cell Line Quantification of Viruses Plaque Assay Efficiency of Plating Animal Infectivity Methods End Point Dilution Viral Reproduction Attachment Penetration Early Steps (Early Proteins) Replication of Nucleic Acids Synthesis of Proteins (Late) Assembly Release

Viruses 3 One-step Growth Curve Latent Period Restriction/ Modification Restriction Enzymes Modification +/- SS RNA Viruses SS DNA Viruses DS Intermediates Reverse Transcriptase BACTERIAL VIRUSES Model Viruses Genetic Engineering RNA Bacteriophage +SS RNA Viruses MS 2 “Male” Specific Phage

Viruses 4 4 Proteins Maturation, Coat, Lysis & RNA Replicase Overlapping Genes SS DNA Icosahedral Phage ФX 174 DS DNA Phage – Lytic T 7, T 4 Head, Tail, Base Plate, Spikes, Tail Fibers, Contractile Sheath Hydoxymethylc ytosine Temperate Bacteriophage Lambda

Viruses 5 Virulent – Temperate Lysogeny Prophage – Provirus Immunity Lambda Repressor Cro protein Transposable Phage Insertion Elements Transposon Mu Phage – Mutator Animal Viruses Eukaryotic Hosts Lytic Infections Persistent Infections Latent Infections

Viruses 6 Cancer Transformation Neoplasm Benign Malignant Metastasis Oncogene +SS RNA Viruses Rhinovirus Foot-and. Mouth Virus Poliovirus Polyprotein Viral Protease -SS RNA Virus Rhabdovirus RNA Dep. RNA Polymerase Influenza Segmented Genome DS RNA Virus Reovirus Rotavirus

Viruses 7 DNA Virus Papovavirus SV 40 Herpesviruses Herpes simplex, Chickenpox, Shingles, Epstein-Barr, Burkitt’s Lymphoma Pox Virus Smallpox Adenovirus Retrovirus Reverse Transcriptase Acquired Immuno deficiency Syndrome – AIDS Viroids SS RNA Circles

Viruses 8 Prions “Mad Cow Disease” Kuru Scrapies Creutzfeldt-Jakob Disease