Getting awake after a long cold sleep: optimization of cryo-preservation techniques for subitanous rotifer eggs

The rotifer Brachionus calyciflorus is a very useful model organism for experimental research in ecology and evolution. This is because this organism is easy to manipulate for experiments and it can be cultured at high densities in the laboratory. Furthermore, the species has short generation times, and large population growth rates. Because of its cyclic parthenogenetic reproduction mode, clones can reproduce asexually for many generations. In contrast to model organisms that reproduce sexually, this has the great advantages that genotypes maintain their genetic characteristics when kept in cultures.

 

Despite its relative ease, the culturing of rotifer clonal lineages over long time spans has still some major costs. The cultures have to be regularly checked and fed. Cultures may accidentally die off and there is always the risk of contamination among cultures. During longer time periods, mutations may also accumulate and gradually change the genetic traits of the clonal lineages of interest.

 

Cryopreservation is a rapidly evolving field. Although applications are currently restricted mainly to tissue cultures and sperm banks, its potential for multicellular organisms is widely recognized. It is the aim of this project to optimize existing cryopreservation protocols for the preservation of B. calyciflorus subitanous eggs. Successful cryopreservation of eggs of this species would strongly enhance eco-evolutionary research on this species because it would help researchers in avoiding all the disadvantages of long term culturing. This topic is suitable for short term internships of MBO and HBO students.

 

3-5 months

 

Steven Declerck, S.Declerck@nioo.knaw.nl