Question

Tissue culture medium is the “soup” that cells are grown in. Briefly describe its composition and best conditions for cell culturing. (Hint: List the names and write down for what purpose we use them)?

Answer 1

Types of tissue cultures: Organ culture: Small bits of organs can be maintained in vitro for days and weeks, preserving their original architecture and function. Organ cultures are useful for the isolation of some viruses which appear to be highly specialised parasites of certain organs. For example, the tracheal ring organ culture is employed for the isolation of coronavirus, a respiratory pathogen. Explant culture: Fragments of minced tissue can be grown as 'explants' embedded in plasma clots. They may also be cultivated in suspension. This was what was originally known as 'tissue culture'. This method is now seldom employed in virology. Adenoid tissue explant cultures were used for the isolation of adenoviruses. Cell culture: This is the type of culture routinely employed for growing viruses. Tissues are dissociated into component cells by the action of proteolytic enzymes such as trypsin and mechanical shaking. The cells are washed, counted and suspended in a growthmedium. The essential constituents of the growth medium are physiologic amounts of essential amino acids and vitamins, salts, glucose, and a buffering system generally consisting of bicarbonate in equilibrium with atmosphere containing about 5% carbon dioxide. This is supplemented with up to 5% calf or fetal calf serum. Antibiotics are added to prevent bacterial contaminants and phenol red is used as indicator. Such media will enable most cell types to multiply with a division time of 24-48 hours. The cell suspension is dispensed in bottles, tubes or petri dishes. The cells adhere to the glass surface and on incubation, divide to form a confluent monolayer sheet of cells covering the surface within about a week.