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Culture TechnologyKultivierungstechniken

Culture Technology

List of media

Callus cultures

Almost all cell lines listed in the catalogue are undifferentiated callus cultures. They have been initiated for biotechnological and research purposes. The cell lines have been maintained from the date of initiation on by continuous subculturing. Cultures have not been tested for embryogenic or organogenic potential.

Suspension Cultures

Suspension cultures are not routinely maintained at the DSMZ. Usually suspension cultures can easily be initiated from callus cultures by clients themselves. For the initiation of a suspension culture the callus contained in one Petri-dish should be carefully disintegrated with sterile forceps and put into a 100 ml Erlenmeyer-flask. App. 10 ml liquid medium is added and the culture shaken on a gyratory shaker at about 100 rotation per minute. Within the next two weeks, depending on the degree of disintegration of the callus, more liquid medium should be added stepwise up to 25 ml per 100 Erlenmeyer-flask. After two or three weeks of growth the culture should be transferred into fresh liquid medium. To improve suspended growth the cultures may be sieved through sterile nylon or steel nets with different pore size during transfer to fresh medium at later stages. As a service, suspension cultures can be initiated from a callus at DSMZ. more

Maintenance

The DSMZ plant cell lines are routinely maintained as living calli under the following growth conditions:

  • at 23 °C
  • at 40 % rel. humidity
  • either in the dark or at ca. 600 lux permanent illumination.

Although controlled humidity is not essential, it should help to reduce the number of random infections. Cultures grown in the dark normally contain no, or only a low concentration of photosynthetic pigments. When these cultures are grown under illumination they may turn green; growth characteristics and secondary metabolism might also change. Depending on the growth rate the cultures have to be transferred to fresh medium in regular intervals as indicated in the catalogue. Transfer of cultures to fresh medium has to be carried out very carefully and with a minimum of mechanical damage. Most cell lines should be transferred with sterile forceps. Very rigid cell lines should be split into smaller pieces with a scalpel.

Transferred callus material should not be placed upside down onto the fresh medium. For optimum growth, fresh callus material from the surface of the callus should be transferred to fresh medium and not base parts of the callus, which often consist of dead cell material. After transfer of the cultures Petri-dishes should be wrapped with parafilm to reduce dessication of the medium.