MBio - Viruses

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Types of DNA Genomes (and examples)
- Circular dsDNA - SV40
- Linear dsDNA - T4 and/or T7
- Linear ssDNA - Parvovirus
- Linear dsRNA - Reovirus
- Linear ssRNA - Poliovirus
Viruses with multiple nucleic acid molecules
- Reovirus (10 dsRNA)
- Influenza (8ssRNA)
5-hydroxymethylcytosine
- Unique base found in T-phage
- Many viruses have unique bases
Nucleocapsid

Capsid + Genome
Membrane envelope
- Layer surrounding the viral capsid
- Not found in all viruses
Select viral taxonomic criteria
- Cellular location of replication
- sense of ssRNA strand (if applicable)
- Number of capsomers (if applicable)
- And more...
Techniques for isolating viruses
- Viruses are tough
- Centrifugation (differential and density)
- Precipitation - (NH₄)₂SO₄ or PG
- Denaturation of contaminants (Chloroform)
Methods for counting viruses
- Direct (With an EM) or indirect (below)
- Hemaglutination assay
- Plaque formation
- LD50 (Animals)
Perimissive cell

Permits viral replication
Outcomes of viral infection
- Abortive - The virus is eliminated
- Restrictive - Virus tends to stick around, quietly (but not silent)
- Productive - Normal viruses infections, virions produced
Ecplipse phase
- Viral particles bound to the target cell
- No longer infectious
Stages of viral replication
- Eclipse phase
- Maturation
- Latency (Both of the above combined)
Two proteins involved in virus activation
- Cro - Activates lysis if concentration is high enough
- Lambda repressor (cI) - Causes lysogeny
Pinocytosis

Entry of an entire virion into an animal cell
Viroid

Virus with no DNA componenet

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Card Set

MBio - Viruses

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MBio

Updated

2017-04-11T03:23:27Z

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