Budding in the dimorphic fungus Phialophora dermatitidis

Area of Science:

• Mycology
• Cell Biology
• Medical Mycology

Background:

• Phialophora dermatitidis is a dimorphic fungus implicated in human infections.
• Understanding its morphological transition is key to understanding its pathogenicity.

Purpose of the Study:

• To compare ultrastructurally the processes of yeast and hyphal bud formation in Phialophora dermatitidis.
• To elucidate the conserved growth mechanisms in both morphological phases of this dimorphic fungus.

Main Methods:

• Transmission electron microscopy was employed to examine the ultrastructure of budding in both yeast and hyphal forms.
• Detailed analysis of cell wall rupture, bud emergence, and septum formation was performed.

Main Results:

• Bud initiation involves a blastic rupture of the parental cell wall, with the new bud wall originating from the inner layer.
• A characteristic collar is formed from the ruptured parental wall.
• Septa formed between parent and daughter cells are complete, lacking septal pores or Woronin bodies.

Conclusions:

• Yeast bud formation and hyphal bud formation in P. dermatitidis share an identical ultrastructural growth process.
• This conserved mechanism in both yeast and mold phases highlights a fundamental aspect of this human pathogenic organism's biology.