Figure 7

Molecular mechanism of action of dicephalic cationic surfactants on C. albicans cells, which takes into consideration domain structure of yeast cells, morphological changes (filamentation) of yeast-like cells to pseudohyphal and hyphal cells as well as ionic and hydrophobic interactions. Yeast cell at the first stage of adhesion starts to synthesize increased amounts of EPS (including exopolysaccharides), which determine the increase in negative surface charge of the cell, together with other cell structures. It results in the ability of double-headed cationic surfactants with their double positive charges to bind to negatively charged cell structures, orienting their hydrophilic heads towards the cell surface. Then the surfactants could interact with other areas of the yeast cell, including more hydrophobic ones, due to increased expression of proteins, which allows the surfactants to penetrate into the cell, change orientation and interact with hydrophobic molecules and cell membranes with their n-variable alkyl chains. Penetration of surfactants into the cell may cause impairment of the mitochondrial process, marked “M” in the picture, and severe oxidative stress through high production of reactive oxygen species (ROS), which in turn could cause further intracellular damage, including damage to the endoplasmic reticulum (ER) and increased synthesis of lipid droplets (LD) as well as damage to cell membranes. The multimodal mechanism of action of dicephalic surfactants may lead to a wide spectrum of intracellular damage in yeast cells, which in turn could lead to disruption of the filamentation process and biofilm formation, or lead to its significant eradication.