Heat shock affects permeability and resistance of Bacillus stearothermophilus spores

Beaman, T C; Pankratz, H. Stuart; Gerhardt, Philipp

doi:10.1128/aem.54.10.2515-2520.1988

Cited by 37 publications

(13 citation statements)

References 25 publications

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“…Electron microscopy. The methods for electron microscopy were those described previously (4,5). Fixed, embedded spores were cut into thin sections and then stained with uranyl acetate and lead citrate.…”

Section: Methodsmentioning

confidence: 99%

Microscopic and Thermal Characterization of Hydrogen Peroxide Killing and Lysis of Spores and Protection by Transition Metal Ions, Chelators, and Antioxidants

Shin

Calvisi

Beaman

et al. 1994

Appl Environ Microbiol

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Killing of bacterial spores by H202 at elevated but sublethal temperatures and neutral pH occurred without lysis. However, with prolonged exposure or higher concentrations of the agent, secondary lytic processes caused major damage successively to the coat, cortex, and protoplast, as evidenced by electron and phase contrast microscopy. These processes were also reflected in changes in differential scanning calorimetric profiles for H202-treated spores. Endothermic transitions in the profiles occurred at lower temperatures than usual as a result of H202 damage. Thus, H202 sensitized the cells to heat damage. Longer exposure to H202 resulted in total disappearance of the transitions, indicative of major disruptions of cell structure. Spores but not vegetative cells were protected against the lethal action of H202 by the transition metal cations Cu+, Cu21, Co2+, Co3+, Fe2+, Fe3+, Mn2+, Ti3+, and Ti4+. The metal chelator EDTA was also somewhat protective, while o-phenanthroline, citrate, deferoxamine, and ethanehydroxydiphosphonate were only marginally so. Superoxide dismutase and a variety of other free-radical scavengers were not protective. In contrast, reducing agents such as sulfhydryl compounds and ascorbate at concentrations of 20 to 50 mM were highly protective. Decoating or demineralization of the spores had only minor effects. The marked dependence of H202 sporicidal activity on moderately elevated temperature and the known low reactivity of H202 itself suggest that radicals are involved in its killing action. However, the protective effects of a variety of oxidized or reduced transition metal ions indicate that H202 killing of spores is markedly different from that of vegetative cells.

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Section: Methodsmentioning

confidence: 99%

Microscopic and Thermal Characterization of Hydrogen Peroxide Killing and Lysis of Spores and Protection by Transition Metal Ions, Chelators, and Antioxidants

Shin

Calvisi

Beaman

et al. 1994

Appl Environ Microbiol

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“…Heat shocking is a recognized method of increasing the likelihood of spore germination. 29 A standard pour plating method with tryptic soy agar was used for culturing. Serial dilutions were performed, with each dilution plated in triplicate.…”

Section: Culturing and Analysismentioning

confidence: 99%

Sterilization of bacterial spores by using supercritical carbon dioxide and hydrogen peroxide

Hemmer¹,

Drews²,

LaBerge³

et al. 2006

J Biomed Mater Res

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It was hypothesized that supercritical carbon dioxide (SC-CO(2)) treatment could serve as an alternative sterilization method at various temperatures (40-105 degrees C), CO(2) pressures (200-680 atm), and treatment times (25 min to 6 h), and with or without the use of a passive additive (distilled water, dH(2)O) or an active additive (hydrogen peroxide, H(2)O(2)). While previous researchers have shown that SC-CO(2) possesses antimicrobial properties, sterilization effectiveness has not been shown at sufficiently low treatment temperatures and cycle times, using resistant bacterial spores. Experiments were conducted using Geobacillus stearothermophilus and Bacillus atrophaeus spores. Spore strips were exposed to SC-CO(2) in commercially available supercritical fluid extraction and reaction systems, at varying temperatures, pressures, treatment times, and with or without the use of a passive additive, such as dH(2)O, or an active additive, such as H(2)O(2). Treatment parameters were varied from 40 to 105 degrees C, 200-680 atm, and from 25 min to 6 h. At 105 degrees C without H(2)O(2), both spore types were completely deactivated at 300 atm in 25 min, a shorter treatment cycle than is obtained with methods in use today. On the other hand, with added H(2)O(2) (<100 ppm), 6 log populations of both spore types were completely deactivated using SC-CO(2) in 1 h at 40 degrees C. It was concluded from the data that large populations of resistant bacterial spores can be deactivated with SC-CO(2) with added H(2)O(2)at lower temperatures and potentially shorter treatment cycles than in most sterilization methods in use today.

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“…It may also result in reversible changes in the tertiary structure of one or more proteins controlling the dormant state of a spore . Activated and dormant spores of B. stearothennophilus can be separated by buoyant density centrifugation into separate bands of differing density (Beaman et al, 1988). That implies activated spores differ significantly from viable, dormant spores.…”

Section: Introductionmentioning

confidence: 99%

Comparison of Predictive Models for Bacterial Spore Population Resources to Sterilization Temperatures

Sapru

Smerage

Teixeira

et al. 1993

Journal of Food Science

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Comparisons of characteristics of recent models and the conventional model of bacterial spore populations during thermal sterilization showed the conventional model was inadequate for general representation because it lacks activation of dormant spores. New models accounting for activation differed in other assumptions but obviated heat shock of indicator spores required when using the conventional model in validations of thermal sterilization. Comparisons of rate constants and simulated and experimental responses of models of B. stearothermophilus spores in constant and dynamic temperatures showed one new model was more general, more accurate and preferred. Arrhenius equations accurately described temperature dependencies of all rate constants of that model.

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Heat shock affects permeability and resistance of Bacillus stearothermophilus spores

Cited by 37 publications

References 25 publications

Microscopic and Thermal Characterization of Hydrogen Peroxide Killing and Lysis of Spores and Protection by Transition Metal Ions, Chelators, and Antioxidants

Microscopic and Thermal Characterization of Hydrogen Peroxide Killing and Lysis of Spores and Protection by Transition Metal Ions, Chelators, and Antioxidants

Sterilization of bacterial spores by using supercritical carbon dioxide and hydrogen peroxide

Comparison of Predictive Models for Bacterial Spore Population Resources to Sterilization Temperatures

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