Infrared Spectra of Bacillus subtilis Spores: The Effect of Growth Media; Conference paper

摘要

We present infrared microscopy spectra of Bacillus subtilis spores cultured in nine types of growth media, and also consider the effect of heat shock on the sporulation of the bacteria and the consequence on the infrared spectral properties of the whole microorganisms. The effect of growth media is elucidated with regard to the variance or invariance of several marker bands in the infrared spectrum of the microorganisms that can be used to effect detection and to some extent identification of the bacterial spores. We evaluate the degree of sporulation apparent in the various samples as a function of the growth media using optical microscopy, and compare the spectra of the samples to that of a sample consisting almost exclusively of vegetative cells. We use a correlation coefficient metric to explore the influence of growth media on detection models programmed using a sample of the microbial spores that is frequently used in field tests sponsored by the Department of Defense. While the results exhibit significant quantitative variation in the spectra as a function of growth media, we note that the qualitative properties of the spore spectra are preserved under the varying growing conditions.