Discovery of small molecule hyperlipid accumulating triggers of algae Chlamydomonas reinhardtii identified via in vivo phenotype based screen (597.1)

Abstract

A large scale in vivo high throughput screen (HTS) was performed to identify small compounds that stimulate lipid production and accumulation using the model organism Chlamydomonas reinhardtii. The HTS employed a 384‐well microplate format in which cells were allowed to grow in the presence of the compounds at 10 μM final concentration for 72 hours. Accumulation of intracellular lipids was assessed using the lipophilic dye Nile Red and growth was monitored at OD600. The screening library included 43,736 compounds (ChemBridge, Corp). A total of 367 active compounds were identified that stimulated lipid accumulation to > 2.5‐fold and did not affect cell viability to give a hit rate of 0.8%. Primary hits were “cherry picked” and the sub‐set of compounds were retested using an 8‐point dose response assay (0.25‐30 µM). Hits were further assessed visually using a Nikon Ti‐inverted microscope (60X) to reconfirm lipid droplet accumulation was induced.. The final set of hits included 306 compounds. These were further compared for structural similarities using Tibco Spotfire Lead Discovery package and resulted in three main structural clusters: compounds with a piperazine, nitrobenzene, and/or adamantine group. The impact of the compounds on cellular metabolism was also characterization by quantifying Chl A, B, starch, protein and toxicity analysis. Currently, we are examining compound effectiveness in additional algal species such as Chlorella sorokiniana UTEX 1230, Tetrachlorella alterans UTEX 2453, C. protothecoides UTEX 29, C. vulgaris UTEX 395, Nannochloropsis sp.Grant Funding Source: Supported by EPSCoR