Release of dipicolinic acid and calcium and activation of <i>Bacillus stearothermophilus</i> spores as a function of time, temperature and pH

Brown, M. R. W.; Melling, J.

doi:10.1111/j.2042-7158.1973.tb09136.x

Cited by 9 publications

(9 citation statements)

References 10 publications

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“…Virtually all do so after treatment with 0.5 N hydrochloric acid (4). Optimum activation is a function of temperature, time, and pH and is also dependent on the presence of buffer and nutrient broth in the suspension medium in order to protect against killing (5). In certain strains of B. stearothermophilus, dormancy may be induced, rather than alleviated, by prior heating at sublethal temperatures (10).…”

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Heat shock affects permeability and resistance of Bacillus stearothermophilus spores

Beaman

Pankratz

Gerhardt

1988

Appl Environ Microbiol

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Heat shock of dormant spores of Bacillus stearothermophilus ATCC 7953 at 100 or 80°C for short times, the so-called activation or breaking of dormancy, was investigated by separating the resulting spores by buoyant density centrifugation into a band at 1.240 g/ml that was distinct from another band at 1.340 g/ml, the same density as the original spores. The proportion of spores at 1.240 g/ml became larger when the original dormant spores were heated for a longer period of time, but integument-stripped dormant spores were quickly and completely converted to spores with a band at 1.240 g/ml. The spores with bands at both 1.240 and 1.340 g/ml were germinable faster than the original dormant spores and thus were considered to be activated. The spores with a band at 1.240 g/ml, which were considered to be fully activated, were apparently permeabilized, with a resulting complete depletion of dipicolinic acid, partial depletion of minerals, susceptibility to lysozyme action, permeation of the gradient medium, changed structural appearance in electron micrographs of thin-sectioned spores, and partly decreased heat resistance (Dloo = 453 min) compared with the original dormant spores (Dloo = 760 min). However, the fully activated spores with a band at 1.240 g/ml, although devoid of dipicolinic acid, still were much more resistant than germinated spores or vegetative cells (Dloo = 0.1 min). The spores with a band at 1.340 g/ml, which were considered to be partly activated, showed no evidence of permeabilization and were much more heat resistant (Dloo = 1,960 min) than the original dormant spores. This phenomenon of super-resistance may involve either in situ induction or selection of a preexisting subpopulation.

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confidence: 99%

Heat shock affects permeability and resistance of Bacillus stearothermophilus spores

Beaman

Pankratz

Gerhardt

1988

Appl Environ Microbiol

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“…~~e u~~~~~r~~p h~~u .~ in connection with the pH of the heating medium but they did not relate it to the heat resistance of the strain. Brown & Melling (1973) studied the release of Dpa in relation to the heat activation of spores of B. steurothermophilus.…”

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The release of dipicolinic acid during heating and its relation to the heat destruction of Bacillus stearothermophilus spores

1985

Journal of Applied Bacteriology

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The rates of dipicolinic acid (Dpa) release and the rates of death were studied for spores of five strains of Bacillus stearothermophilus. It was observed that a highly significant relationship exists between the rate of Dpa release and rate of spore death for the four out of five strains tested and for all test temperatures. At 115 degrees C the rate of Dpa release was found to be faster than the rate of death, equal at 120 degrees C and slower at 125 degrees C. The role of Dpa in heat resistance was considered and a theory is proposed to explain the mechanism by which the heat resistance of bacterial spores is overcome.

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“…Divalent cations, particularly Ca'+, play an important role in the heat stability of bacterial spores (Sugiyama,19.51), and the loss of Ca*+ should lead to loss of heat resistance (El-Mabsout and Stevenson, 1979;Brown and Melling, 1973). Thus, heating spores in the presence of a metal chelator should result in enhanced rate of death.…”

Section: Results and Discussion Heat Resistance And Germinationmentioning

confidence: 99%

Elucidation of the Mechanism of the Acid‐blanch and EDTA Process Inhibition of Clostridium sporogenes PA 3679 Spores

Okereke

Beelman

Doores

et al. 1990

Journal of Food Science

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Acid-blanching followed by addition of ethylenediamine tetraacetic acid to the can brine had been shown to control germination of mesophilic spores following sub-lethal thermal processes. The mechanism of this control was investigated using C. sporogenes PA 3679 spores in buffered solutions. Spore suspensions in buffered 0.05M citric acid solutions, pH 3.5 and 5.8, and Sorensons phosphate buffer, pH 7.0, were heat-activated at 80 "C and then heated for 5 min at 121 "C. The mechanism of inhibition appeared to involve destruction of the spore germination system by heat at reduced pH as a result of collapse of the cortex peptidoglycan layers, possible hydration of the core and concommitant increase in the core volume.

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Release of dipicolinic acid and calcium and activation of Bacillus stearothermophilus spores as a function of time, temperature and pH

Cited by 9 publications

References 10 publications

Heat shock affects permeability and resistance of Bacillus stearothermophilus spores

Heat shock affects permeability and resistance of Bacillus stearothermophilus spores

The release of dipicolinic acid during heating and its relation to the heat destruction of Bacillus stearothermophilus spores

Elucidation of the Mechanism of the Acid‐blanch and EDTA Process Inhibition of Clostridium sporogenes PA 3679 Spores

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