FUNGITOXICITY OF MURAMIDASE - ULTRASTRUCTURAL DAMAGE TO CANDIDA-ALBICANS

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  • 1 January 1982
    • journal article
    • research article
    • Vol. 46  (6) , 627-636
Abstract
The antifungal activity of hen egg-white lysozyme was investigated in vitro using a hypotonic medium designed to support an anabolic cellular state with minimal growth stimulation. The pathogenic yeast C. albicans was sensitive to microgram amounts of hen egg-white lysozyme. This susceptiblity was evidenced by sluggish growth and a dose-dependent killing process. Transmitted and scanning electron microscopic observations on lysozyme-treated C. albicans yeast cells revealed the following ultrastructural modifications: plasmolysis, vacuolar expansion and wrinkled surface configuration; unremitting accumulation of wall-like material that bulged into the periplasmic space; qualitative changes in the organization of the wall. Ongoing structural modifications within the wall were highlighted with the cationic heavy metal dye ruthenium red. A disruption in the permeability of the cytoplasmic membrane was evidenced by the 1st modification and by differential staining characteristics in light microscopy. The superimposed osmotic imbalance was identified as the cause of cell death. It is proposed that lysozyme acts on C. albicans by 2 distinct complementry mechanisms: enzymatic hydrolysis of N-glycosidic bonds that link polysaccharides and structural proteins of the wall and injury to the cytoplasmic membrane as a result of a cationic protein kind of interaction.