Fig 1.
Simplified schematic of SERDS experimental layout.
ECDL: external cavity diode laser; BP: bandpass filter; NDF: neutral density filter; EF: edge filter; Obj: microscope objective; S: sample.
Fig 2.
Single spore Raman spectra of species that yielded usable signals.
The blue and purple curves correspond to Asymmetric Least-Squares (AsLS) [42] background-subtracted raw spectra excited by two slightly different frequencies, while the red curves correspond to the reconstructed, pure Raman spectra obtained through the SERDS protocol outlined in the S1 Appendix.
Fig 3.
Averaged AsLS background-subtracted raw spectra showing fine-scale fluorescence features in the range ~1750 to 2500 cm-1.
Fig 4.
Pure Raman spectra of various species retrieved from the SERDS protocol outlined in the S1 Appendix.
Each spectrum is the average of the SERDS spectra retrieved from n = 100 individual spores. The red circles indicate that a species either produces DOPA melanin when cultured in the presence of tyrosine (A. oryzae) or remains unaffected by DHN pathway inhibitors (A. nidulans and A. flavus). The green square indicates that conidial pigmentation is due to DHN melanin (A. fumigatus). The blue triangle indicates that, while A. niger is not affected by DHN pathway inhibitors, it is thought to polymerize two pigments [47, 48].
Table 1.
Percent accuracy with which single spore spectra from a given species may be classified using the Neural Network (NN) models described in methods and materials.