(Georgia Institute of Technology, 2021-05)
Brashear, Jillian
Rotifers are sensitive indicators of environmental conditions and serve as model organisms for assessing toxicity. It is understood that rotifer cysts (diapausing eggs) are convenient for toxicity assessment because they remove the need to maintain animal cultures, reduce variability in tests, and can be stored for on-demand use. Indeed, cyst-based toxicity tests for the rotifer Proales similis have helped to fill a need for an additional marine animal model to the rotifer Brachionus plicatilis in ecotoxicology. A challenge to implementing tests is the need for readily- available P. similis diapausing eggs, which need to be reliably preserved and hatched on demand. This study explores preservation methods to extend the viability of P. similis eggs. We explore factors including storage temperature, salinity, and the addition of ascorbic acid to measure their effects independently and combined. We found that storing the diapausing eggs at approximately 4℃ in the presence of 20µM ascorbic acid and a 220ppt salinity is effective for extending egg viability. With longer viability, P. similis diapausing eggs are more readily available and thereby valuable as a tool in toxicity assessments.
(Georgia Institute of Technology, 2020-05)
Park, Nancy
This study is the first inquiry into the suitability of the rotifer Proales similis as a test
animal for researchers studying marine pollution. It also introduces a novel toxicity test based on
inhibition of hatching rates of P. similis diapausing embryos. We exposed P. similis to various
concentrations of cadmium, copper, and mercury and then quantified effects on survival,
hatching, reproduction, and ingestion. We found that mortality and cyst hatching endpoints were
more robust to heavy metal toxicity than reproduction or ingestion. Overall, we confirmed that P.
similis is a suitable tool for convenient and quick ecotoxicology assessments, and we established
cyst inhibition as a novel, reliable endpoint for observing effects of toxicity on rotifer
populations.