ELECTRON MICROSCOPY OF CULTURED SPHERULES OF COCCIDIOIDES IMMITIS.

Area of Science:

• Mycology
• Microbiology
• Cell Biology

Background:

• Coccidioides immitis is a fungal pathogen.
• Understanding its life cycle is crucial for disease control.

Purpose of the Study:

• To investigate the in vitro transformation of Coccidioides immitis hyphae into spherules.
• To elucidate the ultrastructural changes during spherule development and endosporulation.

Main Methods:

• In vitro culture of Coccidioides immitis in modified Roessler's medium under CO(2) tension.
• Maintenance of continuous cultures for over 18 months.
• Thin section electron microscopy for ultrastructural analysis.

Main Results:

• Hyphal cells transform into spherules with thickening walls.
• A central accumulation of polysaccharide forms within spherules.
• Nuclei, mitochondria, and lipid particles are observed in hyphal and spherule stages.
• Endospores are formed within spherules and liberated upon wall rupture.

Conclusions:

• The study details the in vitro morphological transformation of Coccidioides immitis.
• Electron microscopy provides insights into the cellular mechanisms of spherule development and reproduction.
• This research contributes to understanding the fungal life cycle relevant to coccidioidomycosis.