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Effects of tricyclazole (5‐methyl‐1,2,4‐triazol[3,4] benzothiazole), a specific DHN–melanin inhibitor, on the morphology of Fonsecaea pedrosoi conidia and sclerotic cells
Author(s) -
Franzen Anderson J.,
Cunha Marcel M.L.,
Batista Evander J.O.,
Seabra Sergio H.,
De Souza Wanderley,
Rozental Sonia
Publication year - 2006
Publication title -
microscopy research and technique
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.536
H-Index - 118
eISSN - 1097-0029
pISSN - 1059-910X
DOI - 10.1002/jemt.20344
Subject(s) - benzothiazole , melanin , conidium , morphology (biology) , chemistry , microbiology and biotechnology , biology , botany , biochemistry , zoology
The influence of tricyclazole (5‐methyl‐1,2,4‐triazol[3,4]benzothiazole), a specific DHN‐melanin inhibitor, on the cell walls and intracellular structures of Fonsecaea pedrosoi conidia and sclerotic cells was analyzed by transmission electron microscopy (TEM), deep‐etching, and field emission scanning electron microscopy. The treatment of the fungus with 16 μg mL −1 of tricyclazole (TC) did not significantly affect fungal viability, but electron microscopy observations showed several important morphological differences between TC‐treated and non‐TC treated cells. Control sclerotic cells presented patched granules, with an average diameter of 47 nm, on the cell surface, which were absent in TC‐treated cells. Also, TC‐treated sclerotic cells showed an undulated relief. TC treatment leads to an accumulation of electron lucent vacuoles in the fungal cytoplasm of both conidia and sclerotic cells, and treated conidia observed by deep etching showed a relevant thickening of the fungal cell wall. Together, these observations support the previous data of our group that F. pedrosoi synthesizes melanin in intracellular organelles. In addition, we suggest that melanin is not only an extracellular constituent but could also be dispersing all over the cell walls and could have an effective role in cross‐linking different cell wall compounds that help maintain the regular shape of the cell wall. Microsc. Res. Tech., 2006. © 2006 Wiley‐Liss, Inc.