Glassy state in Bacillus subtilis spores analyzed by differential scanning calorimetry.
Thermal properties of dried spores of Bacillus subtilis, investigated by differential scanning calorimetry (DSC), were studied. A reversible heat capacity shift ascribable to glass-rubber transition was observed at 90-115 degrees C. The transition was found to be a pressure-inhibited volume-activated event. The decoated spores and the extracted peptidoglycan material exhibited glass transition, suggesting that the cortex could be involved in the event. Furthermore, the glass transition was evident when spores were treated with strong acid, and when the isogenic strain PS578 was scanned, indicating that core integrity and core components are not involved in the occurrence of the event. These results suggest that in the dried B. subtilis spores an amorphous biomaterial, possibly the cortex peptidoglycan, is present as a glass.
Stecchini
Mara Lucia
ML
Department of Food Science, University of Udine, Via Marangoni n. 97, 33100 Udine, Italy. mara.stecchini@dsa.uniud.it
Del Torre
Manuela
M
Venir
Elena
E
Morettin
Alessia
A
Furlan
Patrizia
P
Maltini
Enrico
E
D001412:Bacillus subtilis / Q000254:growth & development / Q000302:isolation & purification / Q000502:physiology*; D002152:Calorimetry, Differential Scanning / Q000379:methods*; D005516:Food Microbiology; D006358:Hot Temperature; D007700:Kinetics; D008954:Models, Biological; D013171:Spores, Bacterial / Q000302:isolation & purification / Q000502:physiology / Q000648:ultrastructure