Figure 2: Heat map of SELDI-TOF MS spectra generated from 42 protein samples (anaerobically and aerobically grown cells of 21 P. acnes strains). All mass ions from each spectrum were analysed using the Ciphergen Biosystems Express Heat Map Software [14]. This software allowed comparison of mass ions (m/z) between various samples and presents the data both as a dendrogram and heat map. The coloured boxes represent intensity of each peak in the SELDI spectra and each colour intensity of the green and the red indicates the difference from the average peak intensity.