Quantitative drug testing model using living sea urchin embryos

Living sea urchin embryos can be used as a model system for quantitative drug testing on developmental mechanisms and morphologies. Here 24 hr Lytechinus pictus sea urchin embryos were incubated with 0M (control), 0.05M, 0.1M or 0.2M alpha lactose, beta lactose, cellobiose, L‐sorbose, L‐fucose, D‐galactosamine, D‐mannoheptose, D‐mannose, D‐palatinose or D‐raffinose at 15 degrees C, pH 8.0 lower calcium artificial sea water, at about 16 embryos per well, containing 100 microliters of suspension per well in 96 well microplates. The embryos were fixed using 6 microliters of 10% formaldehyde per well after 24 hrs incubation with or without the sugars and were quantitatively assessed for specific morphological characteristics such as development of complete or deranged archenterons (primitive guts). Of the sugars tested, in a concentration‐dependent manner embryos incubated with L‐sorbose, D‐galactosamine, D‐mannoheptose, D‐mannose and D‐palatinose quantitatively displayed more deranged archenterons compared with controls in the absence of sugar (p less than 0.05), than found for the other sugars tested. 300–450 embryos were assessed for each sugar concentration tested, totaling over 10,000 embryos that were examined. The results suggest that some sugar structures and not others may play a role in archenteron development. Lower calcium sea water (about 5 mM instead of 10 mM Ca in normal Ca artificial sea water) speeds up entry of molecules into the interior of the embryo. This is a nice model for testing the effects of drugs on developmental events in living embryos (Supported by NIH NIGMS SCORE S0648680, MARC, RISE, the Joseph Drown Foundation, and the Sidney Stern Memorial Trust).