DOH133 Lecture Notes - Lecture 10: Reverse Transcription Polymerase Chain Reaction, Bacteriophage, Lytic Cycle
Differentiate a virus from a bacterium
Virus characteristics
1. Obligatory intracellular parasites
2. Contain DNA or RNA
3. Contain a protein coat
4. Some are enclosed by an envelope
5. Some viruses have spikes
6. Most viruses infect only specific types of cells in one host
7. Host range is determined by specific host attachment sites and cellular
factors
List the properties of an enveloped & non-enveloped virus
Virion: The complete infectious particle structure.
Nucleic acid: DNA or RNA inside particle
Capsid: made up of capsomere subunits; which self-assemble to make capsid
Envelope: If present; host-derived
Spikes: If present; can bind to host receptor
Describe how animal viruses are cultured and their growth curve
By definition, viruses must be grown in a living cell of some type
Animal viruses may be grown in:
- Living animals
- Embryonated eggs
- Immortal cell lines such as HeLa
Pharmacists:
- Culturing is often done to create vaccines. Influenza virus is grown in egg
amniotic cavity for this purpose:
- TIV, LAIV. Therefore a source of egg allergy.
List three techniques used to identify viruses
More difficult than identification of bacterial agents. Viruses cannot be seen using
light microscope. They are difficult to grow, requiring a cell line. Biochemical
growth tests cannot be done. The usual methods of detection are:
1. Cytopathic effects
- The visible effect of viruses on their host cellsCan be cyctocydal
ornon-cytocidal effects.
2. Serological test
- Detect antibodies against viruses in a patient
- Use antibodies to identify viruses in neutralization tests, viral
hemagglutination, and Western blot
3. Nucleic acid amplification
