Fig. 4

Relative levels of intact lipid species of L. aequinoctialis culture cultivated under various melatonin concentrations. A pathway diagram of relative (relative intensity/g) lipid levels was proposed in the Kyoto Encyclopedia of Genes and Genomes (KEGG) database (http://www.genome.jp/kegg/). The data were normalized to an internal standard (PE 17:0/17:0) and then multiplied 100 times for simplicity. Vertical bars and error bars indicate the mean and standard deviation (n = 9, three biological replicates and three technical replicates) of the control group and the 0.1, 1, and 10 µM melatonin treatment groups on days 14 and 28. Black bars indicate no significant differences, red bars indicate statistically significant increases, and blue bars indicate statistically significant decreases by using the Kruskal-Wallis test followed by the Mann-Whitney test as a post hoc analysis with Bonferroni’s correction (p < 0.0083)