Modelling the effects of temperature and osmotic shifts on the growth kinetics of Bacillus weihenstephanensis in broth and food products

Antolinos, Vera; Muñoz-Cuevas, Marina; Ros−Chumillas, María; Periago, Paula M.; Fernández, Pablo S.; Marc, Yvan Le

doi:10.1016/j.ijfoodmicro.2012.06.017

Cited by 13 publications

(8 citation statements)

References 27 publications

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“…We hypothesize that the oligotrophic condition in the CCB may have had a significant effect on the Bacillus growth dynamics that contribute to this variability. For example, long adaptation times are related to stressful conditions affecting the speed of bacterial growth, like limited nutrient availability ( Chorin et al, 1997 ; Schaechter, 2006 ; Antolinos et al, 2011 , 2012 ; Bren et al, 2013 ). Furthermore, estimates of maximum biomass reached can be quite variable because of the influence of overall nutrient availability and sensitivity to the waste material that accumulates during the exponential phase ( Buchanan et al, 1997 ; Chorin et al, 1997 ).…”

Section: Discussionmentioning

confidence: 99%

Variability of rRNA Operon Copy Number and Growth Rate Dynamics of Bacillus Isolated from an Extremely Oligotrophic Aquatic Ecosystem

et al. 2016

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The ribosomal RNA (rrn) operon is a key suite of genes related to the production of protein synthesis machinery and thus to bacterial growth physiology. Experimental evidence has suggested an intrinsic relationship between the number of copies of this operon and environmental resource availability, especially the availability of phosphorus (P), because bacteria that live in oligotrophic ecosystems usually have few rrn operons and a slow growth rate. The Cuatro Ciénegas Basin (CCB) is a complex aquatic ecosystem that contains an unusually high microbial diversity that is able to persist under highly oligotrophic conditions. These environmental conditions impose a variety of strong selective pressures that shape the genome dynamics of their inhabitants. The genus Bacillus is one of the most abundant cultivable bacterial groups in the CCB and usually possesses a relatively large number of rrn operon copies (6–15 copies). The main goal of this study was to analyze the variation in the number of rrn operon copies of Bacillus in the CCB and to assess their growth-related properties as well as their stoichiometric balance (N and P content). We defined 18 phylogenetic groups within the Bacilli clade and documented a range of from six to 14 copies of the rrn operon. The growth dynamic of these Bacilli was heterogeneous and did not show a direct relation to the number of operon copies. Physiologically, our results were not consistent with the Growth Rate Hypothesis, since the copies of the rrn operon were decoupled from growth rate. However, we speculate that the diversity of the growth properties of these Bacilli as well as the low P content of their cells in an ample range of rrn copy number is an adaptive response to oligotrophy of the CCB and could represent an ecological mechanism that allows these taxa to coexist. These findings increase the knowledge of the variability in the number of copies of the rrn operon in the genus Bacillus and give insights about the physiology of this bacterial group under extreme oligotrophic conditions.

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Section: Discussionmentioning

confidence: 99%

Variability of rRNA Operon Copy Number and Growth Rate Dynamics of Bacillus Isolated from an Extremely Oligotrophic Aquatic Ecosystem

et al. 2016

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“…The emulsion characteristics (pH, weak acid and dispersed phase volume ratio) were modified and the impacts were assessed on several scales, namely Bacillus weihenstephanensis germination and outgrowth, and the interface phenomenon with the emulsifier. Bacillus weihenstephanensis was used in this study because of its capacity i) to contaminate chilled and minimally processed food, ii) to constitute a potential danger for customers' health, and iii) to limit products' shelf life leading to economic losses (Antolinos et al, 2012;Desriac et al, 2013).…”

Section: Introductionmentioning

confidence: 99%

Dispersed phase volume fraction, weak acids and Tween 80 in a model emulsion: Effect on the germination and growth of Bacillus weihenstephanensis KBAB4 spores

Léonard-Akkari

Guégan

Courand

et al. 2018

Food Research International

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In foodstuffs, physico-chemical interactions and/or physical constraints between spores, inhibitors and food components may exist. Thus, the objective of this study was to investigate such interactions using a model emulsion as a microbial medium in order to improve bacterial spore control with better knowledge of the interactions in the formulation. Emulsions were prepared with hexadecane mixed with nutrient broth using sonication and were stabilized by Tween 80 and Span 80. The hexadecane ratio was either 35% (v/v) or 50% (v/v) and each emulsion was studied in the presence of organic acid (acetic, lactic or hexanoic) at two pH levels (5.5 and 6). Self-diffusion coefficients of emulsion components and the organic acids were measured by Pulsed Field Gradient-Nuclear Magnetic Resonance (PFG-NMR). The inhibition effect on the spore germination and cell growth of Bacillus weihenstephanensis KBAB4 was characterized by the measure of the probability of growth using the most probable number methodology, and the measure of the time taken for the cells to germinate and grow using a single cell Bioscreen® method and using flow cytometry. The inhibition of spore germination and growth in the model emulsion depended on the dispersed phase volume fraction and the pH value. The effect of the dispersed phase volume fraction was due to a combination of (i) the lipophilicity of the biocide, hexanoic acid, that may have had an impact on the distribution of organic acid between hexadecane and the aqueous phases and (ii) the antimicrobial activity of the emulsifier Tween 80 detected at the acidic pH value. The interface phenomena seemed to have a major influence. Future work will focus on the exploration of these phenomena at the interface.

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“…Antolinos et al . () proposed a model that correctly described the growth of Bacillus weihenstephanensis after temperature and osmotic shifts in refrigerated foods. Previous studies were mostly conducted based on microbial population level.…”

Section: Introductionmentioning

confidence: 99%

Modeling Growth of Pseudomonas Aeruginosa Single Cells with Temperature Shifts

Wang

Dong

Liu

et al. 2016

Journal of Food Safety

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In this article, a single-cell growth and imaging system was used to study how the growth of single cells of Pseudomonas aeruginosa was affected by temperature shifts. An individual-based modeling was conducted to predict the growth of bacterial single cells. We found that shifts to lower temperatures lengthened the division times of P. aeruginosa single cells, whereas shifts to higher temperature caused a rapid shortening of the division times. The coefficient of variation of the division time decreased as the magnitude of the temperature shifts increased which suggested that the variability of the growth of single P. aeruginosa cells was increased with bigger temperature shifts. Furthermore, the individual-based modeling proposed in this study turned out to be a useful way for predicting the stochastic growth of single bacterial cells under nonconstant temperature conditions. PRACTICAL APPLICATIONSIt was deduced that studying the microbial dynamics at the single cell level, which take into account the growth viability and uncertainty of bacterial single cells, could help to establish a more reliable set of microbe-influenced food shelf life and food safety criteria.

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Modelling the effects of temperature and osmotic shifts on the growth kinetics of Bacillus weihenstephanensis in broth and food products

Cited by 13 publications

References 27 publications

Variability of rRNA Operon Copy Number and Growth Rate Dynamics of Bacillus Isolated from an Extremely Oligotrophic Aquatic Ecosystem

Variability of rRNA Operon Copy Number and Growth Rate Dynamics of Bacillus Isolated from an Extremely Oligotrophic Aquatic Ecosystem

Dispersed phase volume fraction, weak acids and Tween 80 in a model emulsion: Effect on the germination and growth of Bacillus weihenstephanensis KBAB4 spores

Modeling Growth of Pseudomonas Aeruginosa Single Cells with Temperature Shifts

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