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Saint Martin C, Caccia N, Darsonval M, Gregoire M, Combeau A, Jubelin G, Dubois-Brissonnet F, Leroy S, Briandet R, Desvaux M. Spatially localised expression of the glutamate decarboxylase gadB in Escherichia coli O157:H7 microcolonies in hydrogel matrices. NPJ Sci Food 2023; 7:55. [PMID: 37838796 PMCID: PMC10576782 DOI: 10.1038/s41538-023-00229-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2023] [Accepted: 10/02/2023] [Indexed: 10/16/2023] Open
Abstract
Functional diversity within isogenic spatially organised bacterial populations has been shown to trigger emergent community properties such as stress tolerance. Considering gadB gene encoding a key glutamate decarboxylase involved in E. coli tolerance to acidic conditions, we investigated its expression in hydrogels mimicking the texture of some structured food matrices (such as minced meat or soft cheese). Taking advantage of confocal laser scanning microscopy combined with a genetically-engineered dual fluorescent reporter system, it was possible to visualise the spatial patterns of bacterial gene expression from in-gel microcolonies. In E. coli O157:H7 microcolonies, gadB showed radically different expression patterns between neutral (pH 7) or acidic (pH 5) hydrogels. Differential spatial expression was determined in acidic hydrogels with a strong expression of gadB at the microcolony periphery. Strikingly, very similar spatial patterns of gadB expression were further observed for E. coli O157:H7 grown in the presence of L. lactis. Considering the ingestion of contaminated foodstuff, survival of E. coli O157:H7 to acidic stomachal stress (pH 2) was significantly increased for bacterial cells grown in microcolonies in acidic hydrogels compared to planktonic cells. These findings have significant implications for risk assessment and public health as they highlight inherent differences in bacterial physiology and virulence between liquid and structured food products. The contrasting characteristics observed underscore the need to consider the distinct challenges posed by these food types, thereby emphasising the importance of tailored risk mitigation strategies.
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Affiliation(s)
- Cédric Saint Martin
- Université Paris-Saclay, INRAE, AgroParisTech, MICALIS Institute, 78350, Jouy-en-Josas, France
- INRAE, UCA, UMR0454 MEDIS, 63000, Clermont-Ferrand, France
| | - Nelly Caccia
- INRAE, UCA, UMR0454 MEDIS, 63000, Clermont-Ferrand, France
| | - Maud Darsonval
- Université Paris-Saclay, INRAE, AgroParisTech, MICALIS Institute, 78350, Jouy-en-Josas, France
| | - Marina Gregoire
- Université Paris-Saclay, INRAE, AgroParisTech, MICALIS Institute, 78350, Jouy-en-Josas, France
| | - Arthur Combeau
- Université Paris-Saclay, INRAE, AgroParisTech, MICALIS Institute, 78350, Jouy-en-Josas, France
| | | | | | - Sabine Leroy
- INRAE, UCA, UMR0454 MEDIS, 63000, Clermont-Ferrand, France
| | - Romain Briandet
- Université Paris-Saclay, INRAE, AgroParisTech, MICALIS Institute, 78350, Jouy-en-Josas, France.
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Martin CS, Jubelin G, Darsonval M, Leroy S, Leneveu-Jenvrin C, Hmidene G, Omhover L, Stahl V, Guillier L, Briandet R, Desvaux M, Dubois-Brissonnet F. Genetic, physiological, and cellular heterogeneities of bacterial pathogens in food matrices: Consequences for food safety. Compr Rev Food Sci Food Saf 2022; 21:4294-4326. [PMID: 36018457 DOI: 10.1111/1541-4337.13020] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2022] [Revised: 07/12/2022] [Accepted: 07/14/2022] [Indexed: 01/28/2023]
Abstract
In complex food systems, bacteria live in heterogeneous microstructures, and the population displays phenotypic heterogeneities at the single-cell level. This review provides an overview of spatiotemporal drivers of phenotypic heterogeneity of bacterial pathogens in food matrices at three levels. The first level is the genotypic heterogeneity due to the possibility for various strains of a given species to contaminate food, each of them having specific genetic features. Then, physiological heterogeneities are induced within the same strain, due to specific microenvironments and heterogeneous adaptative responses to the food microstructure. The third level of phenotypic heterogeneity is related to cellular heterogeneity of the same strain in a specific microenvironment. Finally, we consider how these phenotypic heterogeneities at the single-cell level could be implemented in mathematical models to predict bacterial behavior and help ensure microbiological food safety.
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Affiliation(s)
- Cédric Saint Martin
- MICALIS Institute, Université Paris-Saclay, INRAE, AgroParisTech, Jouy-en-Josas, France.,Université Clermont Auvergne, INRAE, UMR454 MEDIS, Clermont-Ferrand, France
| | - Grégory Jubelin
- Université Clermont Auvergne, INRAE, UMR454 MEDIS, Clermont-Ferrand, France
| | - Maud Darsonval
- MICALIS Institute, Université Paris-Saclay, INRAE, AgroParisTech, Jouy-en-Josas, France
| | - Sabine Leroy
- Université Clermont Auvergne, INRAE, UMR454 MEDIS, Clermont-Ferrand, France
| | - Charlène Leneveu-Jenvrin
- MICALIS Institute, Université Paris-Saclay, INRAE, AgroParisTech, Jouy-en-Josas, France.,Association pour le Développement de l'Industrie de la Viande (ADIV), Clermont-Ferrand, France
| | - Ghaya Hmidene
- Risk Assessment Department, ANSES, Maisons-Alfort, France
| | - Lysiane Omhover
- Aerial, Technical Institute of Agro-Industry, Illkirch, France
| | - Valérie Stahl
- Aerial, Technical Institute of Agro-Industry, Illkirch, France
| | | | - Romain Briandet
- MICALIS Institute, Université Paris-Saclay, INRAE, AgroParisTech, Jouy-en-Josas, France
| | - Mickaël Desvaux
- Université Clermont Auvergne, INRAE, UMR454 MEDIS, Clermont-Ferrand, France
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Saint Martin C, Darsonval M, Grégoire M, Caccia N, Midoux L, Berland S, Leroy S, Dubois-Brissonnet F, Desvaux M, Briandet R. Spatial organisation of Listeria monocytogenes and Escherichia coli O157:H7 cultivated in gel matrices. Food Microbiol 2022; 103:103965. [DOI: 10.1016/j.fm.2021.103965] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2021] [Revised: 12/03/2021] [Accepted: 12/06/2021] [Indexed: 01/01/2023]
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Darsonval M, Julliat F, Msadek T, Alexandre H, Grandvalet C. CtsR, the Master Regulator of Stress-Response in Oenococcus oeni, Is a Heat Sensor Interacting With ClpL1. Front Microbiol 2018; 9:3135. [PMID: 30619203 PMCID: PMC6305308 DOI: 10.3389/fmicb.2018.03135] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2018] [Accepted: 12/04/2018] [Indexed: 11/13/2022] Open
Abstract
Oenococcus oeni is a lactic acid bacterium responsible for malolactic fermentation of wine. While many stress response mechanisms implemented by O. oeni during wine adaptation have been described, little is known about their regulation. CtsR is the only regulator of stress response genes identified to date in O. oeni. Extensively characterized in Bacillus subtilis, the CtsR repressor is active as a dimer at 37°C and degraded at higher temperatures by a proteolytic mechanism involving two adapter proteins, McsA and McsB, together with the ClpCP complex. The O. oeni genome does not encode orthologs of these adapter proteins and the regulation of CtsR activity remains unknown. In this study, we investigate CtsR function in O. oeni by using antisense RNA silencing in vivo to modulate ctsR gene expression. Inhibition of ctsR gene expression by asRNA leads to a significant loss in cultivability after heat shock (58%) and acid shock (59%) highlighting the key role of CtsR in the O. oeni stress response. Regulation of CtsR activity was studied using a heterologous expression system to demonstrate that O. oeni CtsR controls expression and stress induction of the O. oeni hsp18 gene when produced in a ctsR-deficient B. subtilis strain. Under heat stress conditions, O. oeni CtsR acts as a temperature sensor and is inactivated at growth temperatures above 33°C. Finally, using an E. coli bacterial two-hybrid system, we showed that CtsR and ClpL1 interact, suggesting a key role for ClpL1 in controlling CtsR activity in O. oeni.
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Affiliation(s)
- Maud Darsonval
- UMR A. 02.102 Procédés Alimentaires et Microbiologique, AgroSup Dijon, Université Bourgogne Franche-Comté, Dijon, France
| | - Frédérique Julliat
- UMR A. 02.102 Procédés Alimentaires et Microbiologique, AgroSup Dijon, Université Bourgogne Franche-Comté, Dijon, France
| | - Tarek Msadek
- Unité de Biologie des Bactéries Pathogènes à Gram Positif, Institut Pasteur, Paris, France.,CNRS ERL 6002, Paris, France
| | - Hervé Alexandre
- UMR A. 02.102 Procédés Alimentaires et Microbiologique, AgroSup Dijon, Université Bourgogne Franche-Comté, Dijon, France.,Institut Universitaire de la Vigne et du Vin - Jules Guyot, Dijon, France
| | - Cosette Grandvalet
- UMR A. 02.102 Procédés Alimentaires et Microbiologique, AgroSup Dijon, Université Bourgogne Franche-Comté, Dijon, France.,Institut National Supérieur des Sciences Agronomiques, de L'Alimentation et de L'Environnement, AgroSup Dijon, Dijon, France
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Darsonval M, Alexandre H, Grandvalet C. Genetically engineered Oenococcus oeni strains to highlight the impact of estA2 and estA7 esterase genes on wine ester profile. Food Microbiol 2016; 60:21-8. [DOI: 10.1016/j.fm.2016.06.012] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2015] [Revised: 06/10/2016] [Accepted: 06/15/2016] [Indexed: 11/25/2022]
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