Development of an Ecologically Relevant Assay using the Growth of Chlamydomonas reinhardtii to Assess the Effect of Marine Natural Products

Abstract

Marine natural products, with their highly bioactive properties, have been studied in many fields, serving as beneficial compounds in therapeutics and bioengineering. Often produced by the marine microbiome, marine natural compounds can play an important role in defensive symbiotic interactions. However, the ecological relevance of these compounds has rarely been studied. In this research project, I developed an assay to assess the ecological impact of marine natural compounds on an ecologically relevant organism. By evaluating growth effects of two different strains of the model organism C. reinhardtii (CC1690 and CC5325), I am aiming to identify phenotypic differences when exposed to marine natural compounds. The developed experimental set up suggests a starting concentration of 104 cells/ ml TAP media, a DMSO solvent in-plate control of 0.5% v/v, and OD600 measurements at 0, 72, and 104 hrs after the start of the experiment. When performed with chemical compounds, the growth assay showed inhibitory effects of Caffeine and Primaquine Phosphate on CC5325 and promotional effects of Melphalan and Rifampicin on CC1690 for all tested molarities. Growth effects were captured by three different inhibition ratios: Area Under Curve Ratio, Doubling Time Ratio, and Mid-Exponential Growth Phase Ratio. With the suggested experimental set up and statistics, I anticipate providing an ecologically relevant assay to test the effects of marine natural compounds on aquatic organisms. Keywords: Marine Natural Products; Chlamydomonas reinhardtii; Inhibition Ratio; Growth Assay