Chemical structures of 3,4-hydroxy phenyl propionic acid (HPA), 4-hydroxyphenylpyruvic acid (HPPA), 3-4-dihydroxyphenyl lactic acid (DPLA), tyrosine, L-3,4-dihydroxyphenylalanine (DOPA), 3,4-dihydrobenzaldehyde (DHB), 3,4-dihydroxyphenylacetic acid (DOPAC), 3,4-dihyroxybenzoic acid (DHBA), and 3,4 dihydroxymandelic acid (DHMA), together with normalized fluorescence ratio of young adult wild type worms carrying frIs7 treated for 2 h at 25°C with increasing concentrations of the indicated chemical. Data are representative of at least three independent experiments with a minimum of 50 worms for each condition. Compounds previously found to act as DCAR-1 ligands in a Xenopus oocyte system, and their relative potency are indicated (*** medium; ** low; * weak). Tyrosine and DOPA were also tested and had no effect4. As the epidermis of C. elegans is surrounded by a cuticle that is relatively impermeable to many compounds5–6, we cannot formally exclude the possibility that lack of reporter gene expression in our assay results from a failure of a given compound to reach DCAR-1 in vivo. Nor can we exclude the possibility that different compounds have different pharmacokinetic properties.
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5 - Partridge, F. A., Tearle, A. W., Gravato-Nobre, M. J., Schafer, W. R. & Hodgkin, J. The C. elegans glycosyltransferase BUS-8 has two distinct and essential roles in epidermal morphogenesis. Dev Biol 317, 549-559 (2008).
6 - Zheng, S. Q., Ding, A. J., Li, G. P., Wu, G. S. & Luo, H. R. Drug absorption efficiency in Caenorhbditis elegans delivered by different methods. PLoS One 8, e56877 (2013).