Abstract
We have combined the use of atomic force microscopy (AFM) and micro-attenuated total reflectance Fourier transform infrared (micro-ATR-FT-IR) imaging to show the extent of exoenzyme influence around individual hyphae of three fungal species growing on cellophane. AFM data show that surface roughness of the cellophane substrate is significantly lower adjacent to hyphae of Armillaria and Aspergillus, which produce cellulase enzyme, than for Mucor, which has lower cellulase activity. Additionally, the adhesive properties of the cellophane surface are significantly altered within the sphere of influence of the hyphae of Armillaria and Aspergillus. Micro-ATR-FT-IR imaging indicates that the cellophane substrate changes composition immediately adjacent to the hyphae of Armillaria and Aspergillus, but similar spectral changes do not occur in the presence of Mucor. This is consistent with the difference in cellulase enzyme activity in these fungal species. The appearance of new spectral peaks, consistent with those expected in the presence of enzymes and the minor decrease in peaks associated with cellophane adjacent to these hyphae are consistent with the hypothesis that the changes observed by AFM are due to local effects of enzyme action around individual hyphae.