In January 2013 ten scientists from three STAR partners (SCK, SU and IRSN) carried out parallel experiments at the irradiation facility at SCK-CEN as part of STAR’s workpackages 4 and 5 For an intensive period the irradiation facility was filled with 240 Falcon tubes containing 1440 Daphnia, 110 Petri dishes containing 110 nematodes and 100 glass beakers containing more than 1000 Lemna plants!
We are still working with all the samples and data from the experiments, so it’s too early to say what the results have shown. Hopefully we can post an update in a few months…
Why were we doing these experiments?!
SCK were setting up a dose response curve for Lemna growth that will form the basis of later multiple stressor experiments, as well as testing possible dose-dependent DNA damage and possible changes in gene expression triggered by lower dose rates. In addition they were investigating possible recovery from irradiation over a 7 day period.
SU were investigating the whether there were interactive effects (e.g., synergism or antagonism) of the two stressors cadmium and gamma irradiation on Daphnia food assimilation.
IRSN were investigating if chronic gamma irradiation affects life history traits of C. elegans in a dose-dependent way. The experiment started with newly hatched nematodes and ended after they had reproduced (9 days).The results (e.g., dose-response curves, no effect dose rates) will be compared with similar data from acute exposure experiments and used to implement a DEBtox model.
What did we measure?
Lemna: frond area, frond number, fresh weight, ploidy, oxidative DNA damage (ELISA kit for 8OHguanine, disintegration of DNA (DNA laddering), changes in gene expression (RNAsequencing).
Daphnia: the main endpoint was 13C assimilation from 13C-labelled phytoplankton. We also measured feeding rate (number of cells per hour) and mobility/immobility after exposure.
C. elegans: growth (measured from photos taken at different time points) and reproduction (number of larvae/nematodes).
SCK-CEN: Nele Horemans, May Van Hees, Arne Van Hoeck, Robin Nauts and Jean Wannijn