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Plate 33. Inactivation of Viruses. Lytic vs. Lysogenic Cycles. Virus Inactivation. Since viruses aren’t technically “alive”, they cannot be “killed” However, they can be inactivated A virus that cannot replicate is considered inactivated. Susceptible Parts of a Virus.
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Plate 33 Inactivation of Viruses
Virus Inactivation • Since viruses aren’t technically “alive”, they cannot be “killed” • However, they can be inactivated • A virus that cannot replicate is considered inactivated
Susceptible Parts of a Virus • Chemical and physical means are used to inactivate 3 parts of a virus: • Genetic material (DNA or RNA) • Capsid • Envelope (if available)
Inactivation Agents • Alcohol (typically ethyl) • Ultraviolet light • Formaldehyde • Heavy metals • Phenol • Heat Influenza viruses
Alcohol • Virus envelopes are composed of lipids • Lipids are soluble in alcohol • Thus, alcohol can be used to dissolve the lipid envelope of a virus
Ultraviolet Radiation • Shorter wavelengths than visible light, UV light is higher in energy • Causes sunburn • Sterilizes objects by altering the thymine and cytosine bases of nucleic acid • If DNA replication is inhibited, the entity becomes harmless
Formaldehyde • Formaldehyde, CH2O, is a simple organic compound • Used for a variety of biological purposes: • Preserving specimens • Sterilizing vaccines • Treatment of urinary tract infections • Inactivating viruses • Binds with nucleotide bases of RNA/DNA
Heavy Metals • Various heavy metals can be used to inactivate viruses: • Copper • Silver • Mercury • These metals work by altering the proteins in the virus’ capsid • Ex: silver nitrate solution is applied to newborn’s eyes to prevent gonorrhea and Chlamydia
Virus & Heavy Metal • Coincidentally, there is a guitarist named Virus who plays heavy metal Virus
Phenol • Phenol (carbolic acid) is derived from coal tar and is extremely corrosive to biological tissue • In more dilute quantities, phenol was used as an antiseptic for medical procedures (fun fact: Joseph Lister was the “father of modern antisepsis”) • Used to alter and dissolve proteins in viruses, rendering them harmless
Heat • Heat breaks up the chemical bonds of a virus (proteins, lipids, nucleic acids) • Flaming a virus or boiling it will destroy it