Viruses are particles Viruses are NOT living Viruses

Viruses are particles. Viruses are NOT living.

Viruses Infectious particles.

Viruses Virus 1. 2. Protein coat DNA or RNA(not both) 3. 4. 5. Obligate intracellular parasite Not living 25 nm - 1 µ

ST U D Y Bacteria and Viruses

Virus Structure Capsid - protein coat Capsomere - protein unit Envelope - surrounds capsid, host origin. Spikes - special proteins in capsid hemagglutinin, neuraminidase of Influenza virus.

Virus Structure Spikes - special proteins in capsid hemagglutinin, neuraminidase of Influenza virus. Important for attachment to host cells.

Virus Structure Shapes - polyhedral, enveloped, helical.

Virus Structure West Nile virus model. Adenovirus model.

Virus Structure Bacteriophages. Complex structure. 1. 2. 3. 4. Capsid Sheath Baseplate - pins Tail fibers

Virus Structure Bacteriophages.

Counting Viruses Plaque Assay Plate viruses on bacterial lawn or cell cultures.

Growing viruses Replication in: Bacteria Cell culture Animals Embryonated eggs

Growing viruses Cell cultures : Primary - diploid- make monolayer. Continuous- transformed, tumor, lack contact inhibition.

Growing viruses Tumor Cell cultures : Cervical carcinoma- He. La Henrietta Lacks. Diagnosed with cancer. biopsy Feb 9 th 1951 George Gey cultured cells in chicken plasma. Began dividing every 24 hours. Henrietta died on Oct. 4, 1951 - 239 days after her cells began growing in vitro (‘in glass’ = a test tube). in vivo - ‘in a living thing. ’

Growing viruses Tumor Cell cultures : Cervical carcinoma- He. La - the first immortal cell line. found to be transformed by HPV 18. He. La provided the first cells to be used by Jonas Salk to develop the inactivated polio vaccine. He. La cells were given to the National Foundation for Infantile Paralysis at Tuskegee Inst.

Growing viruses Tissue Culture and its tools. STOP

Virus Structure Bacteriophages.

Viral Replication Bacteriophages 1. 2. Attachment of tail fibers Injection of nucleic acid

Viral Replication Bacteriophages 3. Biosynthesis - takes over cell machinery. 4. Maturation - assembles viral parts. 5. Release - 1000 s

Viral Replication DNA viruses: Attachment Penetration

Viral Replication DNA viruses: Attachment Penetration endocytosis Uncoating Replication in nucleus

Viral Replication DNA viruses: Replication in cytoplasm vesicles. Disrupts cell function pathology !! Corona virus in cell cytoplasm.

Viral Replication DNA viruses: Replication release into enviroment Corona virus shed through cell Membrane (budding).

Viral Replication Infection Eclipse Latent Production Yields 1000 -100, 000 particles per cell

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