Quasi-elastic neutron scattering studies on bacterial spores and their hydration water

Spores are bacteria passed into a metabolically dormant state due to starvation and awaiting better external conditions to germinate and colonize the medium again. Their resistance to numerous stress factors is amazing and the reasons behind are still not completely unveiled. Water seems to play an important role for that, as hydration inside the spores is reduced but paired with a remarkable water mobility. To learn more about these facts, we applied a sophisticated approach: we first analysed neutron scattering spectra of whole spores, then we subtracted spectra corresponding to proteins, lipids and sugars to obtain results as close as possible to the water signal. Our procedure revealed strongly reduced rotational dynamics of the proteome, but a high mobility of water molecules and small molecular subgroups at the sub-nanosecond time scale. Such combination might be key to explain the dormant state of spores which is vigilant to revive in adapted conditions.