Thermal properties of bacterial spores and biopolymers.

Differential scanning calorimetry (DSC) measurements of dormant bacterial spores is traditionally associated with an endothermic transition at around 50 degrees C. This endothermic transition was described as an indicator for two main physico-chemical states in spores. These were a glassy state in the dormant spore core as a model for spore dormancy and a heat-activated state that generally facilitates spore resuscitation. The idea of a glassy state in dormant spores is based on the observation that a similar transition as in dormant spores was observed in low moisture biopolymers that are in a glassy state. Thermal properties of spores of Bacillus subtilis and B. cereus in a dormant and germinated, resuscitated state and of an outer and an inner coatless spore mutant of B. subtilis were investigated. Biopolymers with low moisture (<15%) and high moisture (>30%) contents such as maize starch, pectin, RNA and DNA were further studied. Critical evaluation of results revealed that the low temperature transition in dormant spores has some similarities to those observed in glassy biopolymers, but also to those of fully hydrated proteins and therefore does not necessarily indicate a glassy low moisture state. Its origin can also be attributed to the outer spore coats and it occurred at a lower temperature and for a shorter duration to be of significance for thermal heat activation of spores.

[1]  K. Nishinari,et al.  Effects of pH and DMSO content on the thermal and rheological properties of high methoxyl pectin-water gels , 1993 .

[2]  R. Losick,et al.  Gene encoding a morphogenic protein required in the assembly of the outer coat of the Bacillus subtilis endospore. , 1988, Genes & development.

[3]  P. Lillford,et al.  Effects of temperature and heat activation on germination of individual spores of Bacillus subtilis , 1999, Letters in applied microbiology.

[4]  K. Jouppila,et al.  Differential Scanning Calorimetry Glass Transition Temperatures of White Bread and Mold Growth in the Putative Glassy State , 1998 .

[5]  H. Nakagawa,et al.  Studies on Peroxidase of Kiwifruit , 1988 .

[6]  M. Gidley,et al.  Low moisture polysaccharide systems: Thermal and spectroscopic aspects , 1993 .

[7]  D. Heldman,et al.  Changes in Specific Heat of Corn Starch Due to Gelatinization , 1999 .

[8]  P. Lillford,et al.  The glassy state in foods , 1993 .

[9]  H. Martens,et al.  Thermal denaturation of proteins in post rigor muscle tissue as studied by differential scanning calorimetry , 1980 .

[10]  P. Lillford,et al.  Effects of hydration on molecular mobility in phase-bright Bacillus subtilis spores. , 2000, Microbiology.

[11]  S Denyer,et al.  Bioluminescence and spores as biological indicators of inimical processes. , 1994, Society for Applied Bacteriology symposium series.

[12]  C. Biliaderis.  Differential scanning calorimetry in food research—A review☆ , 1983 .

[13]  S. Ablett,et al.  Glass formation and dormancy in bacterial spores , 1999 .

[14]  B. Marshall,et al.  (Symposium on Bacterial Spores : Paper IX). Biophysical Analysis of the Spore , 1970 .

[15]  R. Bucci,et al.  Thermal analysis of food carbohydrates by determination of starch gelatinization phenomena , 1997 .

[16]  S. Koga,et al.  PHYSICAL PROPERTIES OF WATER IN SPORES OF BACILLUS MEGATERIUM , 1968 .

[17]  T. Labuza,et al.  Glassy State in Bacterial Spores Predicted by Polymer Glass-Transition Theory , 1993 .

[18]  Bienvenido O. Juliano,et al.  Thermal characterization of rice starches: a polymeric approach to phase transitions of granular starch , 1986 .

[19]  R. Losick,et al.  Subcellular localization of proteins involved in the assembly of the spore coat of Bacillus subtilis. , 1994, Genes & development.

[20]  P. Lillford,et al.  Rapid particle size distribution analysis of Bacillus spore suspensions , 1999 .

[21]  L. Slade,et al.  Water relationships in starch transitions , 1993 .

[22]  Y. Roos.  Characterization of food polymers using state diagrams , 1995 .

[23]  P. Lillford,et al.  Investigation of bacterial spore structure by high resolution solid-state nuclear magnetic resonance spectroscopy and transmission electron microscopy. , 2001, International journal of food microbiology.

[24]  C. Ma,et al.  Thermal analysis of foods , 1990 .

[25]  B. Brockway.  Thermal analysis of food , 1991 .

[26]  R. Doi.  Sporulation and Germination , 1989 .

[27]  P. Lillford,et al.  Structural analysis of spores of Bacillus subtilis during germination and outgrowth , 2000 .

[28]  P. Wilding,et al.  Differential scanning calorimetric study of muscle and its proteins: myosin and its subfragments. , 1984, Journal of the science of food and agriculture.

[29]  Donald B. Thompson,et al.  EFFECTS OF MOISTURE CONTENT AND DIFFERENT GELATINIZATION HEATING TEMPERATURES ON RETROGRADATION OF WAXY-TYPE MAIZE STARCHES , 1998 .

[30]  T. C. Beaman,et al.  Heat shock affects permeability and resistance of Bacillus stearothermophilus spores , 1988, Applied and environmental microbiology.

[31]  S. Ablett,et al.  The glass transition of amylopectin measured by DSC, DMTA and NMR , 1992 .

[32]  J. Chaires,et al.  Singular value decomposition of 3-D DNA melting curves reveals complexity in the melting process , 1997, European Biophysics Journal.

[33]  T. C. Beaman,et al.  Heat killing of bacterial spores analyzed by differential scanning calorimetry , 1992, Journal of bacteriology.

[34]  M. B. Cole,et al.  Thermal inactivation of Listeria monocytogenes studied by differential scanning calorimetry. , 1991, Journal of general microbiology.

[35]  P. Wilding,et al.  Differential scanning calorimetric studies of muscle and its constituent proteins. , 1977, Journal of the science of food and agriculture.

[36]  C. A. Miles,et al.  Differential scanning calorimetry of bacteria. , 1986, Journal of general microbiology.