Synchronous cultures of the chlorophyte Scenedesmus vacuolatus or other green algae are used to diagnose different modes of action based on functional and population based endpoints. After dosing of the samples to an inorganic algal medium and an inoculation of algae is added, algae are incubated for 2h and 24h. Photosynthetic capacity and fluorescence are evaluated using a Maxi-IPAM fluorometer and a fluorescence plate reader, respectively.
Flow cytometry is applied to quantify cell densities and size distributions as well as subpopulations with specific fluorescence characteristics. This test can differentiate between non-specifically acting compounds and photosynthesis inhibitors, such as herbicides.
Assessment of phytotoxicity caused by herbicides and other modes of action relevant for inhibition of algal growth and reproduction
Schreiber U, Quayle P, Schmidt S, Escher BI, Mueller JF. (2007). Methodology and evaluation of a highly sensitive algae toxicity test based on multiwell chlorophyll fluorescence imaging. Biosens Bioelectron 22:2554-2563.Escher, B.I., Bramaz, N., Mueller, J.F., Quayle, P., Rutishauser, S. and Vermeirssen, E.L.M. (2008). Toxic equivalent concentrations (TEQs) for baseline toxicity and specific modes of action as a tool to improve interpretation of ecotoxicity testing of environmental samples. Journal of Environmental Monitoring, 10(5): 612-621.