Figure 1.

Chlamydomonas reinhardtii small molecule screens. (a) Chronic fitness screen: 96- and 384-well microtiter plates were inoculated with low density cells (1.5 × 10⁵ cells/ml) and small molecules were added to a final concentration of 25 µM (0.5 µg/ml FDA library). Growth was monitored by optical density in our Freedom Evo robotics platform every 30 minutes, resulting in detailed growth curves. A total of 5,445 small molecules were screened with 44% inhibiting Chlamydomonas growth by 35% or more compared to in-plate controls. (b) Acute exposure screen: 96-well microtitre plates were prepared similarly to the chronic screen except with a higher cell density (2 × 10⁶ cells/ml). Plates were assayed for alterations in motility utilizing a phototaxis assay or photosynthesis by assaying fluorescent induction. Of the 476 unique acute inhibitors, 45% were also active in the chronic exposure screen.