Exam 2 - Lecture 4 Flashcards
What is meant by virus cultivation?
Taking virions from a sample and “growing” more of them
What limitations do we face “growing” viruses as opposed to bacteria?
Cultivating viruses requires suitable host cells or a whole organism, and they can’t be grown on standard nutrient agar plates or in nutrient broth
Growing viruses in animals
- What are some examples of lab animals used?
- What are transgenic animals and why are they especially useful?
Common lab animals include mice, guinea pigs, rabbits, hamsters, and primates
Transgenic animals are genetically altered to make them more suitable for cultivating viruses when the original host is not able to be used
Growing viruses in animals
- What are benefits of using animals?
- What are drawbacks of using animals?
Benefits : can see virus in its native environment and study the immune response
Drawbacks : expense, difficulty in purifying, and animal rights concerns
Growing viruses in plants
- What are difficulties when using plants?
The cuticle and cell walls of plant cells makes infection difficult to achieve
- usually requires damage to the plant cells
- difficult to mimic in cells grown in Petri dishes
Growing viruses in plants
- How do we usually inoculate plants?
By scratching virions into the plant and creating damage so the virus can penetrate better
Know the procedure for growing viruses in embryonic eggs (and parts of the egg) well
- Disinfect the outer shell
- Drill small hole into the shell and inject the virus into the chorioallantoic membrane, allantoic cavity, amniotic sac, and yolk sac
- Seal hole with wax
- Look for signs of infection
- Harvest virions from egg
Growing viruses in embryonated eggs
- What are benefits of using eggs?
- What are drawbacks?
Benefits : cheap and unlimited supply, the inside of the egg is naturally sterile and very nutrient rich
Drawbacks: can’t be used for pathogenesis studies, need to purify virions from tissue
Growing lytic bacteriophages in cultured bacterial cells
- How does the purification process work if done in broth?
Add phage to bacteria growing in broth culture, and the phage will infect, kill, and release virions so that it can be purified
Growing lytic bacteriophages in cultured bacterial cells
- What are plaques and how do they form?
A plaque is an area of dead host cells that the phage has killed
Growing lytic eukaryotic viruses
- What is cell culture, where are cells grown during cell culture, and what are benefits of cell culture?
Cell culture is the process of growing cells outside of the animal
- Cells are grown in special dishes/ flasks with buffered growth media
- Benefits : cheap, limitless supply, and total control over conditions
Growing lytic eukaryotic viruses
- What are primary vs continuous cell lines (what are differences between them)?
Primary cell lines consist of cells that have been isolate from a plant or animal, and they’ll only last a few generations. Continuous cell lines use tumor cells that can divide indefinitely
Growing lytic eukaryotic viruses
- How do we grow plant cells in culture?
You first have to strip away the cell wall
What is meant by the concept of viral purification?
Isolating virions from their host cells, other types of virions, and any other contaminants for further identification and study
How can we use plaque formation as a way of purification?
Plaque will form in the cell monolayer and can then be easily transferred