Single-cell analysis reveals individual spore responses to simulated space vacuum

Viability, DPA levels and Raman spectra of spores with and without high vacuum treatment. a, b Viability of B. subtilis PS533 and NCIB 3610 spores that were exposed to high vacuum (<2.6？×？10？5？Pa) for various periods. Spores were first dried in a centrifuge tube and were exposed to high vacuum for 1 or 10 days. Spores that were dried in ambient laboratory pressure but not exposed to high vacuum are the control spores. After high vacuum exposure, spores were suspended in 100？uL distilled water and cultured on LB plates at 37？°C, and spore viability was normalized to that of the control spores. c, d Average Raman spectra of multiple single spores of B. subtilis PS832 c and B. cereus d at atmospheric pressure (1.0？×？105？Pa) (control) and high vacuum. The spectra of spores during the exposure to high vacuum were directly measured using image-guided micro-Raman spectroscopy. The laser power was 20？mW and integration time was 30？s, and spectra shown were averaged over 30 individual spores. *P？<？0.05%; ns, no significanc