This study investigated why some strains of the fungus Aspergillus terreus are resistant to amphotericin B, an important antifungal medicine. Researchers compared a resistant strain with a mutated version that became susceptible to the drug. They found that certain genes called P-type ATPases are more active in resistant strains and may help the fungus pump ions and alter its cell membrane to survive the drug. Additionally, mutations in genes responsible for producing secondary metabolites were linked to the visible changes seen when fungal cultures degenerate.