MICB 202 Chapter Notes - Chapter Virology, Polio: Viremia, Central Nervous System, Antibody
Document Summary
Case study #1: poliovirus example of a picornavirus. Picornavirus: diverse group of 5 genera based on physical properties, serological relatedness, nucleotide sequence. Presence of organic matter may protect virus from inactivation (explains why polio can be spread by drinking swimming pool water). Poliovirus causes paralytic poliomyelitis flaccid muscular paralysis due to death of motor neurons. Only about 1% result in clinical disease. Still causes endemic infections in places like afghanistan, india, nigeria, and has been re-imported to countries where poliovirus had been eradicated. 5 limitations of host cell to overcome in its replication cycle: host has no enzymes that use rna template to make rna. Genome is (+) sense, translated by ribosome upon infection: polio doesn"t have 5" cap. Genome encodes a protease that cleaves polyprotein. Becomes active when secondary, tertiary structures of polypeptide formed: must compete for host ribosomes. Virus has protease (eif4g) that damages protein associated with 5" cap. Damages cap binding complex, can"t bind to ribosome.
