Cultivation Flashcards
Why is there no viral growth on a plate?
Viruses do not have genetic capability to multiply by division. Outside the host cell, they are inert/dormant particles
Viruses need living host cells to replicate and generate next progeny of viruses.
Inside host cell, virus hijacks and utilized host cell machinery to produce its proteins and nucleic acid for next gen
Possible ways to grow/cultivate viruses
Cell/tissue culture
Inoculation in embryonated egg
Lab animal
Monolayer cultures
When the bottom of the culture vessel is covered with a continuous layer of cells, usually one cell in thickness.
Primary cell culture
Maintenance of growth of cells dissociated directly from the parental tissue (like kidney) of human or animal origin
Best culture systems for isolation and propagation of viruses
Used in producing viral vaccines
Subculture
transfer of cells from one culture vessel to another vessel
This is periodically required to provide fresh nutrients and growing space for continuous growing cell lines
Types of cell lines
Finite/diploid
Continuous
Finite/diploid cell lines
Limited life span
Limited number of cell generations
Derived mainly from embryos; or from secondary cell cultures
Can be used for vaccine production
Continuous Cell lines
Derived directly from cancer cells
Can divide indefinitely
FDA prohibits use in vaccine production
Culture medium
Provides all the necessary nutrients (amino acids, inorganic salts, vitamins, and glucose) required for growth of cells
Serum in culture media
Fetal bovine serum
Required for growth and maintenance of cells
Helps in cell adhesion, regulate cell membrane permeability and provide nutrients
Phenol Red pH indicator
Indicates changes in pH (fall) by changing color of medium from red to orange or yellow
Carbon dioxide level
It is necessary to use exogenous CO2 when using media buffered with a CO2-bicarbonate based buffer to maintain pH of medium
Antimicrobial agents
to prevent contamination with bacteria, mycoplasma, yeast, molds, etc
Trypsin
Proteolytic enzyme used to detach and dissociate cells while subculturing
Cytopathic effect
Damage or morphological changes to host cells during virus invasion
