dopamine or DHI as the substrate. Twenty-five lg of SHLS was pre-incubated with either 25 lL of L-DOPA (2 mM), dopamine (2 mM) or DHI (2 mM) at RT for at least 10 min before being incubated with 25 lL of one of the Gram-negative bacteria (V. harveyi and V. parahaemolyticus), Gram-positive bacteria (B. subtilis) or the filamentous fungus (F. solani) at RT for 1 h with constant shaking. The treated microbial cells were serially diluted and dotted onto LB or PDA plates (for bacterial or fungal counts, respectively, as appropriate). The number of bacterial colonies or fungal hyphal body as colony forming units (CFUs) was then counted after incubation at 30 C for 18–48 h. SHLS pre-incubated with 0.1 mM PTU before being mixed with PO substrates and microbial cells were included as control. Microbial cells incubated with SHLS or substrates alone were included as control groups, and no significant differences between the mean colony counts, except for DHI due to its cytotoxicity (Zhao et al., 2007, 2011), were observed (data not shown).