Virus Cultivation Methods

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Questions and Answers

What do viruses require for replication?

Chemical reagents

Artificial nutrient medium

Living host cells (correct)

Bacteriophages

Viruses can be grown outside a living organism in an artificial environment.

True

What is the purpose of culturing animal viruses?

Identification and diagnosis of pathogens, production of vaccines, and basic research

Viruses can be harvested from the growth medium after infecting __________ cells.

host Signup and view all the answers

Which of the following is a method used to separate virions from host cells?

Filtration Signup and view all the answers

Match the following terms to their descriptions:

In vivo = Cultivation within a living organism In vitro = Cultivation outside a living organism Bacteriophage = Virus that infects bacteria Plaque = Clear zone in bacterial lawn indicating lysis Signup and view all the answers

All viruses can be cultured on a dense layer of bacteria.

False Signup and view all the answers

What type of medium can be used to grow bacteriophages?

0.7% soft agar Signup and view all the answers

What is one method used to extract cells from tissues?

Mechanical scraping Signup and view all the answers

Primary cell cultures can be grown indefinitely without any limitations.

False Signup and view all the answers

What term is used for cells grown in a primary culture that have reached sufficient density and come into contact with each other?

secondary cell culture Signup and view all the answers

The HeLa cell line is an example of an __________ cell line that can be grown indefinitely.

immortal Signup and view all the answers

What is a key characteristic of continuous cell cultures?

They can grow indefinitely. Signup and view all the answers

Contact inhibition accelerates the growth of primary cell cultures once they become too dense.

False Signup and view all the answers

What is the function of antibodies in the context of hemagglutination assays?

To bind to hemagglutinins on viruses Signup and view all the answers

Match the following terms with their definitions:

Primary culture = Cells extracted from tissues for the first time Secondary culture = Cells that have become too dense Continuous cell culture = Cells that can grow indefinitely Hemagglutination = Clumping of red blood cells due to virus interaction Signup and view all the answers

Study Notes

Cultivation of Viruses

Viruses, unlike bacteria, require a living host cell for replication.
Infected host cells (eukaryotic or prokaryotic) can be cultured and harvested to produce virus.
Virions can be separated from host cells through centrifugation or filtration.
Filters remove larger particles than virions, allowing viruses to be collected in the filtrate.

Virus Cultivation Methods

In vivo: Viruses can be grown within a whole living organism (animal, plant), or in an artificial environment.
In vitro: Viruses can be grown in a test tube, cell culture flask, or an agar plate.
Bacteriophages: Grown in a bacterial lawn (dense layer of bacteria) on a Petri dish. Plaque formation indicates areas where bacteriophages have lysed bacterial cells.
Plaque Assay: Clear zones (plaques) in the bacterial lawn indicate where bacteriophages have replicated.

Animal Virus Cultivation

Animal viruses require cells within a host animal or tissue culture cells derived from an animal.
Animal virus cultivation is crucial for identifying and diagnosing pathogenic viruses, producing vaccines, and basic research.
In vivo source examples: Embryonated bird eggs (chickens, turkeys) or whole animals.
The embryo or animal functions as an incubator for viral replication.
Specific tissue location is critical, as viruses have a tissue tropism requiring specific sites for growth.

In Vitro Culture of Viruses

Primary cell culture: Freshly prepared from animal organs/tissues.
Cells are released using mechanical scraping, mincing, or enzymes (trypsin, collagenase).
Primary cells need a solid surface (glass, plastic) for attachment and growth.
Primary cells have a limited lifespan.

In Vitro Culture of Viruses (cont'd)

Secondary cell culture: Cells enter contact inhibition when their density becomes too high and growth must be sustained with transfer to a new medium and thus creating a secondary cell culture.
Continuous cell lines: Derived from transformed cells/tumors, they can be subcultured repeatedly, growing indefinitely (immortal). A notable example is the HeLa cell line.

Assays for Virus Identification

Hemagglutination Inhibition (HAI): Identifies specific viruses using an indirect method.
Antibodies bind to virus components like hemagglutinins preventing erythrocytes from interacting directly with the virus.
No agglutination indicates successful antibody binding to the viral components.

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Description

Explore the fascinating world of virus cultivation techniques. This quiz covers both in vivo and in vitro methods, including the specific procedures used for bacteriophages and animal viruses. Test your knowledge on how viruses are harvested and grown in various environments.