Synchrotron FTIR Microspectroscopy of Fungal Hyphae

Fungi are interesting from many perspectives, as humans and fungi have remarkably similar metabolism. Fungi have smaller and less complex genomes, and tractable growth characteristics, making them amenable to study. Fungi are an emerging threat for human health, especially for immune compromised and HIV patients. Anti-fungal drugs are extremely toxic, expensive, cure rates are low, and cures seldom last m ore than six months. With regard to food, fungi have both good and bad characteristics. Fungal interactions with plant roots called mycorrhizae are thought to have been essential for emergence of plants onto land ca 450 million years ago, and currently mycorrhizae are associated with 95% of plant species. However, fungal plant pathogens are also the most important threat to the global food supply. Hyphal tips grow continuously through a complex, inter-related suite of biochemical processes.1,2 Synchrotron FT-IR can provide high spatial resolution (< 10 μm pixel size), in situ, biochemical analyses, an area of increasing importance in the post-genomic era, as gene functions and gene networks are coming under direct scrutiny. While more precise chemical identification is possible with LC-MS and GC-MS, such techniques require sample homogenization, thus all spatial resolution is lost. FTIR spectra of bulk samples of some common fungi have been partially assigned..3,4 We have analyzed high spatial resolution synchrotron FT-IR maps of Aspergillus nidulans cells containing the hypA1 allele, a single-gene temperature-sensitive lesion.5