lecture 4 Flashcards
Why is there no viral group outside of the host cell?
- cannot multiply by division, outside host cell they are inert/dormant particles
- need living host cell to replicate and generate progeny
- virus hijacks and utilizes host cell machinery to produce its proteins and nucleic acid for next generation
possible ways to grow/cultivate viruses
- cell/tissue culture
- inoculation in embryonated egg
- lab animals
monolayer culture
-when bottom of culture vessel is covered in continuous layer of cells, usually one cell in thickness
primary cell culture
-maintenance of growth of cells dissociated from the parental tissue (such as kidney or liver) of human or animal origin
advantages of primary cell culture
- best culture system for isolation and propagation of viruses
- used in producing viral vaccines
secondary culture/transfer culture
- subculture/passage-transfer of cells from one culture vessel to another
- periodically required to provide fresh nutrients and growing space for continuously growing cell lines
types of cell lines
- finite/diploid
- continuous
finite/diploid cell lines
- have limited life span
- go through a limited number of generations
- derived mainly from embryos; or from secondary cell cultures
- can be used for vaccine production
continuous cell lines
- acquire ability to divide indefinitely
- derived directly from cancer cells
- cannot be used for vaccine production (prohibited by FDA)
culture medium
-provides all necessary nutrients (amino acids, inorganic salts, vitamins, and glucose) required for the growth of cells
serum in culture media
- most widely used serum supplement is fetal bovine serum, FBS
- required for growth and maintenance of the cells
- helps in cell adhesion, regulates membrane permeability, provides nutrients
phenol red pH indicator
-indicates change in pH (fall in pH) by changing color of medium from red to orange or yellow
CO2 level
-necessary to use exogenous CO2 when using media buffered with a CO2-bicarbonate based filter to maintain pH of medium
antimicrobial agents
-prevent contamination from bacteria, mycoplasma, yeast, molds, etc
Trypsin (protease)
-proteolytic enzyme used to detach and dissociate cells while subculturing
