Cell/Tissue culture – growing cells/tissue in the lab

• can be used for genetic manipulation, research etc.

• different techniques and growth media depending on cell type

What things do you think you would need for all cell types to grow?

Many things are needed by all cell types:

• source of cells

• suitable container

• growth medium to provide all necessary nutrient

• gas exchange

• control of environmental factors (e.g. pH, temp.)

• method to measure cell growth

• avoid contamination from micro-organisms

Microbial Cells

Bacterial and fungal cultures are used for:

1.Energy – ethanol (biofuel) and methane (biogas) production

2.Food – single cell biomass, vinegar etc.

3.Biodegradation – treatment of sewage

• can be grown in batch culture without dilution until maximum quantity reached

• in correct conditions, cultures show exponential growth until a factor becomes limiting

• eventually will die out if not sub-cultured

• need to ensure cells from culture cannot escape and contaminate

• fragile, and conditions need to be more carefully controlled than for microbial cells

Answer following in sentences:

1.What nutrients must be present in the growth medium?

2.Why might it be useful to include universal indicator and antibiotics?

Salt, amino acids, vitamins, glucose

Indicator to monitor pH, antibiotics to kill microbes

Foetal bovine serum (FBS) is essential also, as it contains chemicals for cell proliferation.

2 types of animal culture:

1. Primary culture – cells are taken from tissue (sometimes tumours e.g. HeLa) using proteolytic enzymes, however, cells only have a limited lifespan

2. Continuous cell line – cells taken from an already established culture, they will proliferate indefinitely given suitable media and space

• cells need a solid surface to ‘anchor’ on to

• cells grow as a monolayer until confluent (joined)

• proliferation stops until they are sub-cultured

• cells from culture can be cloned to make a culture of identical cells

• cultures are used in medical research

• media simpler than that of animal cell culture

• plant cells show nuclear totipotency – they can develop into any type of cell

=> whole plants can be generated from culture

• explants (small piece of plant tissue) are grown

• protoplasts are produced (plant cells with the wall removed)

• protoplasts divide to produce a callus (mass of undifferentiated cells)

• cells from callus can be sub-cultured with plant hormones (e.g. auxins and cytokinins) to promote differentiation

• protoplasts from different species can be fused together

• these plants are called hybrids

• what is this process called? (Think back to Higher!)

Somatic fusion

Plant cultures can be used to:

• grow pathogen-free plantlets and plants

• produce new plant varieties