Open AccessMorphometric and densitometric study of the biogenesis of electron‐dense granules in Fonsecaea pedrosoi
Author(s) -
Franzen Anderson J,
Souza Wanderley,
Farina Marcos,
Sales Alviano Celuta,
Rozental Sonia
Publication year - 1999
Publication title -
fems microbiology letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.899
H-Index - 151
eISSN - 1574-6968
pISSN - 0378-1097
DOI - 10.1111/j.1574-6968.1999.tb13531.x
Subject(s) - acridine orange , melanin , electron microscope , transmission electron microscopy , cytoplasm , biology , ultrastructure , granule (geology) , biophysics , confocal , chemistry , staining , microbiology and biotechnology , anatomy , materials science , biochemistry , nanotechnology , optics , paleontology , genetics , physics
Abstract Fonsecaea pedrosoi is a polymorphic pathogenic fungus, etiological agent of chromoblastomycosis, that synthesizes a melanin‐like pigment. Although this pigment has been described as a component of the outer layers of the cell wall, electron‐dense cytoplasmic bodies have also been visualized. In this work, we have correlated the appearance of intracellular electron‐dense granules with the melanization process in F. pedrosoi . For this, conidial forms were grown under conditions where melanin was not synthesized. Afterwards, cells were incubated in Hank's medium supplemented with bovine fetal serum, at 37°C, to stimulate the pigment production. The genesis of cytoplasmic bodies, with different stages of electron density, was demonstrated by transmission electron microscopy. The appearance of fungal acidic compartments, visualized by confocal laser scanning microscopy in cells stained with acridine orange, was time coincident with the formation of electron‐dense granules observed by transmission electron microscopy. The quantification of granule numbers as well as morphometric and densitometric studies were performed.