Why apply Synchrotron FTIR Microspectroscopy SFTIRM

A recent pilot study by Kneipp et al. has shown that the microdisperse accumulation of PrP in 263K infected Syrian hamster is only detectable when using small apertures (this phenomenon was termed the optical dilution effect ). In this study, spectra from DRG of terminally diseased 263K hamsters were acquired using such a device, which provides a spatial resolution approaching the diffraction limit of mid-infrared light. Results showed that the peak at around 1657 cm associated with a-helical protein structures (see Table 11.2), decreased and shifted to a lower frequency in spectra from infected animals, and the peak at 1637 cm indicative of (3-sheet structure, increased. In some spectra from infected hamsters, an additional peak at 

For a more detailed insight into disease progression the relative contributions of an increased p-sheet or a decreased a-helix (or both) to the observed phenomenon of scrapie-induced variations in p-sheet to a-helix ratios needed to be elucidated as well. Furthermore, investigations on animals sacrificed at different time points after peroral challenge had to be performed for additional information about the spatial and temporal course of protein composition and prion protein accumulation in scrapie infected nervous tissue during disease progression. 

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