Glass formation and dormancy in bacterial spores

Autor: David R. Martin, Peter J. Lillford, Arthur H. Darke, Steve Ablett
Rok vydání: 1999
Předmět:
Zdroj: International Journal of Food Science & Technology. 34:59-69
ISSN: 1365-2621
0950-5423
DOI: 10.1046/j.1365-2621.1999.00240.x
Popis: Differential scanning calorimetry (DSC) and nuclear magnetic resonance (NMR) techniques were used to obtain evidence whether a glassy state exists within fully hydrated dormant Bacillus subtilis spores. DSC thermograms of hydrated dormant spores contained two major transitions; one at approximately 60 degrees C assigned to be associated with the initial 'activation' stage for germination, and the other at approximately 120 degrees C assigned to be associated with the 'inactivation' process (i.e. killing of the spores). The peak at approximately 60 degrees C had characteristics which were all consistent with at least some region of the compartmentalised structure of fully hydrated dormant spores being in a glassy state. Solid (CPMAS) and liquid state (SPMAS) mobility resolved (13)C NMR spectroscopy studies on the calcium dipicolinic acid (CaDPA) resonances, which are only present in the central protoplast of bacterial spores, showed it to be present in an amorphous solid-like environment. The DSC and NMR results were both found to be consistent with the hypothesis that the dormancy of bacterial spores is due to at least the central protoplast region being maintained in a low moisture content glassy state.
Databáze: OpenAIRE
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