![]() ![]() However, the timing of this process is difficult to predict accurately as spores are generally seen to germinate at different times and at different rates. In practice this should be done by triggering spores with germinants or physical treatments that allow their ‘rapid return to life’ through the process of germination and outgrowth. Therefore, it would be advantageous to deliberately drive spores in food into their vegetative form in order to facilitate their inactivation with relatively mild food preservation treatments. In contrast, the metabolically active form of the bacterium, the vegetative cell, is much easier to kill than the dormant spore. Some may even survive harsh preservation treatments that are commonly used in some of the industrial processes. The metabolically dormant spores are extremely resistant to environmental stresses. For example, spores of Gram-positive bacteria such as Bacillus and Clostridium cause food spoilage and food borne diseases. Spore-forming bacteria are an aggravating problem for the food industry and public health. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.Ĭompeting interests: The authors have declared that no competing interests exist. ![]() This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.įunding: RP is supported by a European Union ERASMUS MUDUS grant (EMECW 15 India) and ATB is supported by a grant from the Dutch Foundation for Applied Sciences (STW 10431). Received: NovemAccepted: FebruPublished: March 25, 2013Ĭopyright: © 2013 Pandey et al. Loyola University Medical Center, United States of America However, the distribution and the mean outgrowth time and the generation time of vegetative cells, emerging from untreated and thermally injured spores, were similar.Ĭitation: Pandey R, Ter Beek A, Vischer NOE, Smelt JPPM, Brul S, Manders EMM (2013) Live Cell Imaging of Germination and Outgrowth of Individual Bacillus subtilis Spores the Effect of Heat Stress Quantitatively Analyzed with SporeTracker. The heat treatment had a significant influence on the average time to the start of germination (increased) and the distribution and average of the duration of germination itself (increased). Compared to control samples fewer spores germinated (41.1% less) and fewer grew out (48.4% less) after the treatment. The influence of a heat stress of 85☌ for 10 min on germination, outgrowth, and subsequent vegetative growth was investigated in detail. The observed generation times of vegetative cells were comparable to those obtained in well-aerated shake flask cultures. subtilis vegetative cells were monitored. In order to check the efficiency of the chamber, growth and division of B. Image analysis with the purposely built program “SporeTracker” allows for automated data processing from germination to outgrowth and vegetative doubling. Typically, we examined around 90 starting spores/cells for ≥4 hours per experiment. This chamber was used to analyze Bacillus subtilis spore germination, outgrowth, as well as subsequent vegetative growth. In order to examine spore heterogeneity we made a novel closed air-containing chamber for live imaging. Mechanistic details of the cause of this heterogeneity are necessary. Spore germination and outgrowth progression are often very heterogeneous and therefore, predictions of microbial stability of food products are exceedingly difficult. ![]() Vegetative cells are formed by germination of spores followed by a more extended outgrowth phase. ![]() spores can remain in a dormant, stress resistant state for a long period of time. Spore-forming bacteria are a special problem for the food industry as some of them are able to survive preservation processes. ![]()
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