Fungal-Metal Interactions: A Review of Toxicity and Homeostasis

Area of Science:

• Environmental Microbiology
• Mycology
• Biochemistry

Background:

• Metal nanoparticles are increasingly used as antifungals, leading to more fungal-metal interactions.
• Understanding these interactions is crucial for addressing the rise of fungal superbugs.
• Current knowledge of fungal resistance mechanisms to metals is limited, especially in filamentous fungi.

Purpose of the Study:

• To review and synthesize current knowledge on fungal homeostasis of essential metals (zinc, copper, iron, manganese) and silver.
• To comprehensively examine metal resistance mechanisms in yeast and filamentous fungi.
• To identify knowledge gaps, particularly concerning silver resistance and mechanisms in filamentous fungi.

Main Methods:

• Literature review and synthesis of existing research on fungal metal resistance.
• Analysis of microarray data to identify resistance mechanisms in response to metal exposure.
• Comparative examination of resistance strategies between Saccharomyces cerevisiae (yeast) and filamentous fungi.

Main Results:

• Metal resistance in yeast primarily involves down-regulation of importers, metallothionein use, and vacuolar sequestration.
• Filamentous fungi predominantly utilize cellular ion export for metal resistance, with some employing vacuolar sequestration and cell wall storage.
• Resistance to zinc, copper, iron, and manganese is well-documented in yeast but only partially understood in filamentous fungi; silver resistance is poorly understood in both.

Conclusions:

• Fungal resistance mechanisms vary significantly between yeast and filamentous fungi, with implications for antifungal development.
• Further research is needed to elucidate silver resistance pathways and expand understanding in filamentous fungi.
• Addressing knowledge gaps is critical for managing fungal infections and mitigating the emergence of antifungal resistance.