Figure 4. Histological images of sea fans infected with Aspergillus sydowii and presence of melanin both as a band and in amoebocytes as melanosomes.

A) Histological preparation of an infected coral stained with H&E showing individual fungal hyphae (F) in skeleton and surrounded by melanin (M). Note granular amoebocytes (ga) aggregated near melanin and fungal hyphae. Scale bar = 25 µm. B) Histological preparation of an infected coral showing multiple amoebocytes containing melanin granules in contact with the thick layer of melanin preventing A. sydowii hyphae within the axial skeleton (at left) from contacting the sea fan tissue (on right). Fontana-Masson staining procedure, scale bar = 25 µm. C) Close up of an amoebocyte containing melanin granules (Mg) and black stained melanin (M) layer surrounding fungus (F). Fontana-Masson staining procedure, scale bar = 10 µm D) Uninfected coral stained with Fontana-Masson's procedure showing lack of melanin and melanin granules. Scale bar = 10 µm.