A Diffusion Model to Quantify Membrane Repair Process in Listeria monocytogenes Exposed to High Pressure Processing Based on Fluorescence Microscopy Data
Nikparvar, Bahareh (Norwegian University of Science and Technology. Department of Chemical Engineering)
Subires Orenes, Alicia (Universitat Autònoma de Barcelona. Departament de Ciència Animal i dels Aliments)
Capellas Puig, Marta (Universitat Autònoma de Barcelona. Departament de Ciència Animal i dels Aliments)
Hernandez-Herrero, Manuela (Universitat Autònoma de Barcelona. Departament de Ciència Animal i dels Aliments)
Crauwels, Peter (Ulm University. Institute of Microbiology and Biotechnology)
Riedel, Christian U. (Ulm University. Institute of Microbiology and Biotechnology)
Bar, Nadav (Norwegian University of Science and Technology. Department of Chemical Engineering)

Date:	2021
Abstract:	The effects of environmental stresses on microorganisms have been well-studied, and cellular responses to stresses such as heat, cold, acids, and salts have been extensively discussed. Although high pressure processing (HPP) is becoming more popular as a preservation method in the food industry, the characteristics of the cellular damage caused by high pressure are unclear, and the microbial response to this stress has not yet been well-explored. We exposed the pathogen Listeria monocytogenes to HPP (400 MPa, 8 min, 8°C) and found that the high pressure created plasma membrane pores. Using a common staining technique involving propidium iodide (PI) combined with high-frequency fluorescence microscopy, we monitored the rate of diffusion of PI molecules into hundreds of bacterial cells through these pores on days 0, 1, 2, 3, and 4 after pressurization. We also developed a mathematical dynamic model based on mass transfer and passive diffusion laws, calibrated using our microscopy experiments, to evaluate the response of bacteria to HPP. We found that the rate of diffusion of PI into the cells decreased over the 4 consecutive days after exposure to HPP, indicating repair of the pressure-created membrane pores. The model suggested a temporal change in the size of pores until closure. To the best of our knowledge, this is the first time that pressure-created membrane pores have been quantitatively described and shown to diminish with time. In addition, we found that the membrane repair rate in response to HPP was linear, and growth was temporarily arrested at the population level during the repair period. These results support the existence of a progressive repair process in some of the cells that take up PI, which can therefore be considered as being sub-lethally injured rather than dead. Hence, we showed that a subgroup of bacteria survived HPP and actively repaired their membrane pores.
Grants:	Ministerio de Ciencia e Innovación PCIN-2016-072
Rights:	Aquest document està subjecte a una llicència d'ús Creative Commons. Es permet la reproducció total o parcial, la distribució, la comunicació pública de l'obra i la creació d'obres derivades, fins i tot amb finalitats comercials, sempre i quan es reconegui l'autoria de l'obra original.
Language:	Anglès
Document:	Article ; recerca ; Versió publicada
Subject:	High pressure processing ; Listeria monocytogenes ; Mathematical modeling ; Membrane damage ; Repair process ; Fluorescence microscopy
Published in:	Frontiers in microbiology, Vol. 12 (may 2021) , ISSN 1664-302X

DOI: 10.3389/fmicb.2021.598739
PMID: 34054742

14 p, 1.6 MB

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