Researchers discovered that a specific sugar compound called β-1,6-glucan is found in the spore-like reproductive structures (conidia) of the fungus Aspergillus fumigatus but not in its growing filaments (mycelium). Using advanced nuclear magnetic resonance technology, they identified the KRE6 gene as responsible for making this sugar and found that removing this gene makes the fungus more vulnerable to certain chemicals that damage fungal cell walls.