Callus and Suspension cultures

different types of cultures, suspension culture, batch culture etc.

1. CALLUS & SUSPENSION CULTURES Lecture #7

2. CALLUS CULTURE When explants are cultured on a suitable GR combination, many of its cells undergo division. Even mature and certain differentiated, e.g., Parenchyma and often Collenchyma, cells undergo changes become meristematic; its called as “Dedifferentiation”. Dedifferentiation involves enhanced RNA and Protein synthesis.

3. Types of Cultures:

4. CALLUS CULTURE: Tissues and cells cultured on an agar gelled medium form and unorganised mass of cells called callus . These culture need to be sub-cultured every 3-5 weeks. Risk free, easy to handle.

5. SUSPENSION CULTURES: Tissues and cells cultured in liquid medium is known as Suspension culture. They often produce suspension of single cells and clumps. Liquid cultures are constantly agitated, generally by a gyratory shaker @ 100-250ppm. This enhances the aeration and dissociation of cell clumps into smaller pieces.

6. This suspension cultures are used for large scale production. Need to be sub-cultured every week. The suspension cultures are majorly three types Batch cultures Continuous cultures Immobilized cultures

7. Batch cultures: A technique used to grow microorganisms or cells . A limited supply of nutrients for growth is provided; when these are used up, or some other factor becomes limiting, the culture declines. Cells , or products that the organisms have made, can then be harvested from the culture . The cell number or biomass of batch culture exhibits a typical sigmoidal growth curve.

8. LAG Phase: during this phase cell number or biomass is unchanged. LOG Phase: during this phase the cell number rapidly increases in geometrical progression. Stationary Phase: In this phase end phase where cell number does not change.

9. Batch cultures are maintained by sub-culturing. These cultures are mostly used in initiation of cell suspension i.e. single cell culture. These are most convenient to use than continuous cultures hence mostly used.

10. Continuous culture: These cultures are maintained in a steady state for a long period by draining out the used (or) spent medium and adding the fresh medium. such subculture systems are either closed (or) open type . Closed : The cells separated from used medium taken out for replacement and added back to the suspension culture. So that the cell biomass keeps on increasing.

11. Open : Both cells and the used medium are taken out from open continuously cultures and replaced by equal volume of fresh medium. The replacement volume is so adjusted that cultures remain at sub-maximal growth indefinitely.

12. Immobilized cell cultures: Plant cells and cell groups may be encapsulated in a suitable material, e.g., agarose and calcium alginate gels. These gel beads are placed on a suitable frame structures or may be packed in a column of a membrane wire cloth. Liquid medium is continuously run through the column to provide aeration to cells.