3.5. In vitro effect of the melanization reaction products on the morphology of F. solani
To further examine the cytotoxicity of three phenolic substrates (L-DOPA, dopamine and DHI) on the F. Solani cells, the fungus conidia were incubated with 2 mM or 20 mM of each substrates and morphology of cells were then observed under the SEM. As shown in Fig. 5, no adverse effect on the morphology of F. solani cells was detected after incubated with 2 mM of L-DOPA and dopamine. However, when the concentration was increase ten times, the distinct cell morphologies were evident (Fig. 5), with the presence of burst cells and clearly visible membrane pores after treatment with 20 mM L-DOPA, and the decomposition and rupture of cell membranes after treatment with 20 mM dopamine. In the case of DHI, an extensive effect in the fungal cell morphology including the presence of fungal cell debris, as observed after treatment with 2 mM DHI, and a higher frequency of more severely damaged and ruptured cells with a preponderance of cell debris after treatment with 20 mM DHI was visualized (Fig. 5).