title: The Heat Resistance of Microbial Cells Represented by D Values Can be Estimated by the Transition Temperature and the Coefficient of Linear Expansion.
abstract: We previously developed a method for evaluating the heat resistance of microorganisms by measuring the transition temperature at which the coefficient of linear expansion of a cell changes. Here, we performed heat resistance measurements using a scanning probe microscope with a nano thermal analysis system. The microorganisms studied included six strains of the genus Bacillus or related genera, one strain each of the thermophilic obligate anaerobic bacterial genera Thermoanaerobacter and Moorella, two strains of heat-resistant mold, two strains of non-sporulating bacteria, and one strain of yeast. Both vegetative cells and spores were evaluated. The transition temperature at which the coefficient of linear expansion due to heating changed from a positive value to a negative value correlated strongly with the heat resistance of the microorganism as estimated from the D value. The microorganisms with greater heat resistance exhibited higher transition temperatures. There was also a strong negative correlation between the coefficient of linear expansion and heat resistance in bacteria and yeast, such that microorganisms with greater heat resistance showed lower coefficients of linear expansion. These findings suggest that our method could be useful for evaluating the heat resistance of microorganisms.
authors.affiliation: Nano-Microbio Research Laboratory.
authors.forename: Koichi
authors.initials: K
authors.lastname: Nakanishi
authors.forename: Akinori
authors.initials: A
authors.lastname: Kogure
authors.forename: Keiji
authors.initials: K
authors.lastname: Deuchi
authors.forename: Ritsuko
authors.initials: R
authors.lastname: Kuwana
authors.forename: Hiromu
authors.initials: H
authors.lastname: Takamatsu
authors.forename: Kiyoshi
authors.initials: K
authors.lastname: Ito
mesh_terms: D001419:Bacteria / Q000528:radiation effects*; D055598:Chemical Phenomena; D005658:Fungi / Q000528:radiation effects*; D006358:Hot Temperature; D050296:Microbial Viability / Q000528:radiation effects*; D008853:Microscopy / Q000379:methods*; D044366:Transition Temperature