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Zoz F, Guyot S, Grandvalet C, Ragon M, Lesniewska E, Dupont S, Firmesse O, Carpentier B, Beney L. Management of Listeria monocytogenes on Surfaces via Relative Air Humidity: Key Role of Cell Envelope. Foods 2021; 10:foods10092002. [PMID: 34574112 PMCID: PMC8468791 DOI: 10.3390/foods10092002] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2021] [Revised: 08/20/2021] [Accepted: 08/24/2021] [Indexed: 12/25/2022] Open
Abstract
Although relative air humidity (RH) strongly influences microbial survival, its use for fighting surface pathogens in the food industry has been inadequately considered. We asked whether RH control could destroy Listeria monocytogenes EGDe by envelope damage. The impact of dehydration in phosphate-buffered saline (PBS) at 75%, 68%, 43% and 11% RH on the bacterial envelope was investigated using flow cytometry and atomic force microscopy. Changes after rehydration in the protein secondary structure and peptidoglycan were investigated by infrared spectroscopy. Complementary cultivability measurements were performed by running dehydration–rehydration with combinations of NaCl (3–0.01%), distilled water, city water and PBS. The main results show that cell membrane permeability and cell envelope were greatly altered during dehydration in PBS at 68% RH followed by rapid rehydration. This damage led cells to recover only 67% of their initial volume after rehydration. Moreover, the most efficient way to destroy cells was dehydration and rehydration in city water. Our study indicates that rehydration of dried, sullied foods on surfaces may improve current cleaning procedures in the food industry.
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Affiliation(s)
- Fiona Zoz
- Univ. Bourgogne Franche-Comté, AgroSup Dijon, PAM UMR A 02.102, F-21000 Dijon, France; (F.Z.); (C.G.); (M.R.); (S.D.); (L.B.)
- Mérieux NutriSciences–70 Mail Marcel Cachin, F-38600 Fontaine, France
| | - Stéphane Guyot
- Univ. Bourgogne Franche-Comté, AgroSup Dijon, PAM UMR A 02.102, F-21000 Dijon, France; (F.Z.); (C.G.); (M.R.); (S.D.); (L.B.)
- Correspondence: ; Tel.: +33-3-8077-2387
| | - Cosette Grandvalet
- Univ. Bourgogne Franche-Comté, AgroSup Dijon, PAM UMR A 02.102, F-21000 Dijon, France; (F.Z.); (C.G.); (M.R.); (S.D.); (L.B.)
| | - Mélanie Ragon
- Univ. Bourgogne Franche-Comté, AgroSup Dijon, PAM UMR A 02.102, F-21000 Dijon, France; (F.Z.); (C.G.); (M.R.); (S.D.); (L.B.)
| | - Eric Lesniewska
- ICB UMR CNRS 6303, Université de Bourgogne Franche-Comté, F-21078 Dijon, France;
| | - Sébastien Dupont
- Univ. Bourgogne Franche-Comté, AgroSup Dijon, PAM UMR A 02.102, F-21000 Dijon, France; (F.Z.); (C.G.); (M.R.); (S.D.); (L.B.)
| | - Olivier Firmesse
- Laboratory for Food Safety, French Agency for Food, Environmental and Occupational Health & Safety (ANSES), Université Paris-Est, F-94700 Maisons-Alfort, France; (O.F.); (B.C.)
| | - Brigitte Carpentier
- Laboratory for Food Safety, French Agency for Food, Environmental and Occupational Health & Safety (ANSES), Université Paris-Est, F-94700 Maisons-Alfort, France; (O.F.); (B.C.)
| | - Laurent Beney
- Univ. Bourgogne Franche-Comté, AgroSup Dijon, PAM UMR A 02.102, F-21000 Dijon, France; (F.Z.); (C.G.); (M.R.); (S.D.); (L.B.)
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Chi NTQ, Lan NTH, Toyama K, Mukai Y. Microbial inspection of a Vietnamese hospital kitchen with reference to a Japanese hospital kitchen. J Food Saf 2020. [DOI: 10.1111/jfs.12827] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Affiliation(s)
- Nguyen Thi Quynh Chi
- Division of Health and Social Services Graduate Course of Health and Social Work, Kanagawa University of Human Services Graduate School Kanagawa Japan
| | - Nguyen Thi Huong Lan
- Nutrition and Food Safety Department Institute for Preventive Medicine and Public Health, Hanoi Medical University Hanoi Vietnam
- Nutrition and Dietetics Department Saint Paul Hospital Hanoi Vietnam
| | - Kenji Toyama
- Division of Health and Social Services Graduate Course of Health and Social Work, Kanagawa University of Human Services Graduate School Kanagawa Japan
- Department of Clinical Nutrition, School of Nutrition and Dietetics, Faculty of Health and Social Work Kanagawa University of Human Services Kanagawa Japan
| | - Yuuka Mukai
- Division of Health and Social Services Graduate Course of Health and Social Work, Kanagawa University of Human Services Graduate School Kanagawa Japan
- Department of Food Hygiene and Function, School of Nutrition and Dietetics, Faculty of Health and Social Work Kanagawa University of Human Services Kanagawa Japan
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Bitencourt TA, Lang EAS, Sanches PR, Peres NTA, Oliveira VM, Fachin AL, Rossi A, Martinez-Rossi NM. HacA Governs Virulence Traits and Adaptive Stress Responses in Trichophyton rubrum. Front Microbiol 2020; 11:193. [PMID: 32153523 PMCID: PMC7044415 DOI: 10.3389/fmicb.2020.00193] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2019] [Accepted: 01/27/2020] [Indexed: 12/16/2022] Open
Abstract
The ability of fungi to sense environmental stressors and appropriately respond is linked to secretory system functions. The dermatophyte infection process depends on an orchestrated signaling regulation that triggers the transcription of genes responsible for adherence and penetration of the pathogen into host-tissue. A high secretion system is activated to support the host-pathogen interaction and assures maintenance of the dermatophyte infection. The gateway of secretion machinery is the endoplasmic reticulum (ER), which is the primary site for protein folding and transport. Current studies have shown that ER stress that affects adaptive responses is primarily regulated by UPR and supports fungal pathogenicity; this has been assessed for yeasts and Aspergillus fumigatus, in regard to how these fungi cope with host environmental stressors. Fungal UPR consists of a transmembrane kinase sensor (Ire1/IreA) and a downstream target Hac1/HacA. The active form of Hac is achieved via non-spliceosomal intron removal promoted by endonuclease activity of Ire1/IreA. Here, we assessed features of HacA and its involvement in virulence and susceptibility in Trichophyton rubrum. Our results showed that exposure to antifungals and ER-stressing agents initiated the activation of HacA from T. rubrum. Interestingly, the activation occurs when a 20 nt fragment is removed from part of the exon-2 and part of intron-2, which in turn promotes the arisen of the DNA binding site motif and a dimer interface domain. Further, we found changes in the cell wall and cellular membrane composition in the ΔhacA mutant as well as an increase in susceptibility toward azole and cell wall disturbing agents. Moreover, the ΔhacA mutant presented significant defects in important virulence traits like thermotolerance and growth on keratin substrates. For instance, the development of the ΔhacA mutant was impaired in co-culture with keratinocytes or human nail fragments. Changes in the pro-inflammatory cytokine release were verified for the ΔhacA mutant during the co-culture assay, which might be related to differences in pathogen-associated molecular patterns (PAMPs) in the cell wall. Together, these results suggested that HacA is an integral part of T. rubrum physiology and virulence, implying that it is an important molecular target for antidermatophytic therapy.
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Affiliation(s)
- Tamires A. Bitencourt
- Department of Genetics, Ribeirão Preto Medical School, University of São Paulo, São Paulo, Brazil
| | - Elza A. S. Lang
- Department of Genetics, Ribeirão Preto Medical School, University of São Paulo, São Paulo, Brazil
| | - Pablo R. Sanches
- Department of Genetics, Ribeirão Preto Medical School, University of São Paulo, São Paulo, Brazil
| | - Nalu T. A. Peres
- Department of Genetics, Ribeirão Preto Medical School, University of São Paulo, São Paulo, Brazil
- Department of Microbiology, Institute of Biological Sciences, Federal University of Minas Gerais, Belo Horizonte, Brazil
| | - Vanderci M. Oliveira
- Department of Genetics, Ribeirão Preto Medical School, University of São Paulo, São Paulo, Brazil
| | - Ana Lúcia Fachin
- Department of Biotechnology, University of Ribeirão Preto, Ribeirão Preto, Brazil
| | - Antonio Rossi
- Department of Genetics, Ribeirão Preto Medical School, University of São Paulo, São Paulo, Brazil
| | - Nilce M. Martinez-Rossi
- Department of Genetics, Ribeirão Preto Medical School, University of São Paulo, São Paulo, Brazil
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Rapoport A, Rusakova A, Khroustalyova G, Walker G. Thermotolerance in Saccharomyces cerevisiae is linked to resistance to anhydrobiosis. Process Biochem 2014. [DOI: 10.1016/j.procbio.2014.07.006] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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Dato L, Berterame NM, Ricci MA, Paganoni P, Palmieri L, Porro D, Branduardi P. Changes in SAM2 expression affect lactic acid tolerance and lactic acid production in Saccharomyces cerevisiae. Microb Cell Fact 2014; 13:147. [PMID: 25359316 PMCID: PMC4230512 DOI: 10.1186/s12934-014-0147-7] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2014] [Accepted: 10/08/2014] [Indexed: 01/25/2023] Open
Abstract
Background The great interest in the production of highly pure lactic acid enantiomers comes from the application of polylactic acid (PLA) for the production of biodegradable plastics. Yeasts can be considered as alternative cell factories to lactic acid bacteria for lactic acid production, despite not being natural producers, since they can better tolerate acidic environments. We have previously described metabolically engineered Saccharomyces cerevisiae strains producing high amounts of L-lactic acid (>60 g/L) at low pH. The high product concentration represents the major limiting step of the process, mainly because of its toxic effects. Therefore, our goal was the identification of novel targets for strain improvement possibly involved in the yeast response to lactic acid stress. Results The enzyme S-adenosylmethionine (SAM) synthetase catalyses the only known reaction leading to the biosynthesis of SAM, an important cellular cofactor. SAM is involved in phospholipid biosynthesis and hence in membrane remodelling during acid stress. Since only the enzyme isoform 2 seems to be responsive to membrane related signals (e.g. myo-inositol), Sam2p was tagged with GFP to analyse its abundance and cellular localization under different stress conditions. Western blot analyses showed that lactic acid exposure correlates with an increase in protein levels. The SAM2 gene was then overexpressed and deleted in laboratory strains. Remarkably, in the BY4741 strain its deletion conferred higher resistance to lactic acid, while its overexpression was detrimental. Therefore, SAM2 was deleted in a strain previously engineered and evolved for industrial lactic acid production and tolerance, resulting in higher production. Conclusions Here we demonstrated that the modulation of SAM2 can have different outcomes, from clear effects to no significant phenotypic responses, upon lactic acid stress in different genetic backgrounds, and that at least in one genetic background SAM2 deletion led to an industrially relevant increase in lactic acid production. Further work is needed to elucidate the molecular basis of these observations, which underline once more that strain robustness relies on complex cellular mechanisms, involving regulatory genes and proteins. Our data confirm cofactor engineering as an important tool for cell factory improvement. Electronic supplementary material The online version of this article (doi:10.1186/s12934-014-0147-7) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Laura Dato
- Dipartimento di Biotecnologie e Bioscienze, Università degli Studi di Milano-Bicocca, Piazza della Scienza 2, 20126, Milan, Italy.
| | - Nadia Maria Berterame
- Dipartimento di Biotecnologie e Bioscienze, Università degli Studi di Milano-Bicocca, Piazza della Scienza 2, 20126, Milan, Italy.
| | - Maria Antonietta Ricci
- Dipartimento di Bioscienze, Biotecnologie e Biofarmaceutica, Università degli Studi di Bari Aldo Moro, Via Orabona 4, 70125, Bari, Italy.
| | - Paola Paganoni
- Dipartimento di Biotecnologie e Bioscienze, Università degli Studi di Milano-Bicocca, Piazza della Scienza 2, 20126, Milan, Italy.
| | - Luigi Palmieri
- Dipartimento di Bioscienze, Biotecnologie e Biofarmaceutica, Università degli Studi di Bari Aldo Moro, Via Orabona 4, 70125, Bari, Italy.
| | - Danilo Porro
- Dipartimento di Biotecnologie e Bioscienze, Università degli Studi di Milano-Bicocca, Piazza della Scienza 2, 20126, Milan, Italy.
| | - Paola Branduardi
- Dipartimento di Biotecnologie e Bioscienze, Università degli Studi di Milano-Bicocca, Piazza della Scienza 2, 20126, Milan, Italy.
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Grube M, Gavare M, Rozenfelde L, Rapoport A. Anhydrobiosis in yeast: FT-IR spectroscopic studies of yeast grown under conditions of severe oxygen limitation. Biotechnol Appl Biochem 2014; 61:474-9. [PMID: 24923424 DOI: 10.1002/bab.1165] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2013] [Accepted: 09/17/2013] [Indexed: 01/31/2023]
Abstract
Anhydrobiosis is a unique state of living organisms when metabolism is temporarily and reversibly delayed in response to the extreme desiccation of cells. The production of dry active preparations of yeast grown under anaerobic conditions is not currently possible because preparations are extremely sensitive to the dehydration procedure, though they could be very helpful in different biotechnological processes, including bioethanol production. To characterize mechanisms responsible for such sensitivity to the dehydration procedure, Fourier transform infrared spectroscopy was used to study the composition of aerobically grown yeast Saccharomyces cerevisiae resistant to dehydration and grown under conditions of severe oxygen limitation and sensitive to dehydration. Results indicated that significantly lower amounts of lipids in cells, grown under conditions of severe oxygen limitation, may be related to the mechanisms of sensitivity. Dehydration of both resistant and sensitive S. cerevisiae cells was accompanied by similar changes in main cellular compounds. Amounts of nucleic acids and proteins decreased slightly, whereas that of lipids and carbohydrates increased. Artificially reduced sensitivity to dehydration in S. cerevisiae cells, grown under conditions of severe oxygen limitation, led to the increase in the lipid concentration. The chemical composition of S. cerevisiae membranes is proposed to dictate the resistance to dehydration in resistant and sensitive cells.
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Affiliation(s)
- Mara Grube
- Environmental Microbiology Laboratory, Institute of Microbiology and Biotechnology, University of Latvia, Riga, Latvia
| | - Marita Gavare
- Environmental Microbiology Laboratory, Institute of Microbiology and Biotechnology, University of Latvia, Riga, Latvia
| | - Linda Rozenfelde
- Laboratory of Cell Biology, Institute of Microbiology and Biotechnology, University of Latvia, Riga, Latvia
| | - Alexander Rapoport
- Laboratory of Cell Biology, Institute of Microbiology and Biotechnology, University of Latvia, Riga, Latvia
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Randez-Gil F, Córcoles-Sáez I, Prieto JA. Genetic and Phenotypic Characteristics of Baker's Yeast: Relevance to Baking. Annu Rev Food Sci Technol 2013; 4:191-214. [DOI: 10.1146/annurev-food-030212-182609] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Francisca Randez-Gil
- Departamento de Biotecnología, Instituto de Agroquímica y Tecnología de los Alimentos, Consejo Superior de Investigaciones Científicas, 46980 Paterna, Valencia, Spain;
| | - Isaac Córcoles-Sáez
- Departamento de Biotecnología, Instituto de Agroquímica y Tecnología de los Alimentos, Consejo Superior de Investigaciones Científicas, 46980 Paterna, Valencia, Spain;
| | - José A. Prieto
- Departamento de Biotecnología, Instituto de Agroquímica y Tecnología de los Alimentos, Consejo Superior de Investigaciones Científicas, 46980 Paterna, Valencia, Spain;
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Feng X, Krishnan K, Richie DL, Aimanianda V, Hartl L, Grahl N, Powers-Fletcher MV, Zhang M, Fuller KK, Nierman WC, Lu LJ, Latgé JP, Woollett L, Newman SL, Cramer RA, Rhodes JC, Askew DS. HacA-independent functions of the ER stress sensor IreA synergize with the canonical UPR to influence virulence traits in Aspergillus fumigatus. PLoS Pathog 2011; 7:e1002330. [PMID: 22028661 PMCID: PMC3197630 DOI: 10.1371/journal.ppat.1002330] [Citation(s) in RCA: 82] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2011] [Accepted: 09/06/2011] [Indexed: 12/20/2022] Open
Abstract
Endoplasmic reticulum (ER) stress is a condition in which the protein folding capacity of the ER becomes overwhelmed by an increased demand for secretion or by exposure to compounds that disrupt ER homeostasis. In yeast and other fungi, the accumulation of unfolded proteins is detected by the ER-transmembrane sensor IreA/Ire1, which responds by cleaving an intron from the downstream cytoplasmic mRNA HacA/Hac1, allowing for the translation of a transcription factor that coordinates a series of adaptive responses that are collectively known as the unfolded protein response (UPR). Here, we examined the contribution of IreA to growth and virulence in the human fungal pathogen Aspergillus fumigatus. Gene expression profiling revealed that A. fumigatus IreA signals predominantly through the canonical IreA-HacA pathway under conditions of severe ER stress. However, in the absence of ER stress IreA controls dual signaling circuits that are both HacA-dependent and HacA-independent. We found that a ΔireA mutant was avirulent in a mouse model of invasive aspergillosis, which contrasts the partial virulence of a ΔhacA mutant, suggesting that IreA contributes to pathogenesis independently of HacA. In support of this conclusion, we found that the ΔireA mutant had more severe defects in the expression of multiple virulence-related traits relative to ΔhacA, including reduced thermotolerance, decreased nutritional versatility, impaired growth under hypoxia, altered cell wall and membrane composition, and increased susceptibility to azole antifungals. In addition, full or partial virulence could be restored to the ΔireA mutant by complementation with either the induced form of the hacA mRNA, hacAi, or an ireA deletion mutant that was incapable of processing the hacA mRNA, ireAΔ10. Together, these findings demonstrate that IreA has both HacA-dependent and HacA-independent functions that contribute to the expression of traits that are essential for virulence in A. fumigatus. Aspergillus fumigatus is the predominant mold pathogen of humans, responsible for life-threatening infections in patients with depressed immunity. The fungus is highly adapted for secretion, a feature that it uses to extract nutrients from the host environment. High rates of protein secretion can overwhelm the protein folding capacity of the endoplasmic reticulum (ER). The resulting ER stress is alleviated by the unfolded protein response (UPR), a signaling pathway that is triggered by the ER-membrane sensor IreA and executed by the downstream transcription factor HacA. This paper uncovers a novel role for IreA in the expression of multiple adaptive traits that allow the fungus to cope with stress conditions that are encountered during infection. Gene expression profiling of ΔireA and ΔhacA mutants revealed that IreA signals predominantly through the canonical IreA-HacA UPR pathway under extreme conditions of ER stress, but has unexpected HacA-dependent and HacA-independent functions even in the absence of ER stress. These findings establish IreA as an important regulator of A. fumigatus pathogenicity and suggest that therapeutic targeting of the dual functions of this protein could be an effective antifungal strategy.
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Affiliation(s)
- Xizhi Feng
- Department of Pathology & Laboratory Medicine, University of Cincinnati College of Medicine, Cincinnati, Ohio, United States of America
| | - Karthik Krishnan
- Department of Pathology & Laboratory Medicine, University of Cincinnati College of Medicine, Cincinnati, Ohio, United States of America
| | - Daryl L. Richie
- Department of Pathology & Laboratory Medicine, University of Cincinnati College of Medicine, Cincinnati, Ohio, United States of America
| | | | - Lukas Hartl
- Unité des Aspergillus, Institut Pasteur, Paris, France
| | - Nora Grahl
- Department of Immunology & Infectious Diseases, Montana State University, Bozeman, Montana, United States of America
| | - Margaret V. Powers-Fletcher
- Department of Pathology & Laboratory Medicine, University of Cincinnati College of Medicine, Cincinnati, Ohio, United States of America
| | - Minlu Zhang
- Division of Biomedical Informatics, Cincinnati Children's Hospital Research Foundation, Cincinnati, Ohio, United States of America
| | - Kevin K. Fuller
- Department of Pathology & Laboratory Medicine, University of Cincinnati College of Medicine, Cincinnati, Ohio, United States of America
| | - William C. Nierman
- The J. Craig Venter Institute, Rockville, Maryland, United States of America
| | - Long Jason Lu
- Department of Medicine, University of Cincinnati College of Medicine, Cincinnati, Ohio, United States of America
| | | | - Laura Woollett
- Department of Pathology & Laboratory Medicine, University of Cincinnati College of Medicine, Cincinnati, Ohio, United States of America
| | - Simon L. Newman
- Department of Medicine, University of Cincinnati College of Medicine, Cincinnati, Ohio, United States of America
| | - Robert A. Cramer
- Department of Immunology & Infectious Diseases, Montana State University, Bozeman, Montana, United States of America
| | - Judith C. Rhodes
- Department of Pathology & Laboratory Medicine, University of Cincinnati College of Medicine, Cincinnati, Ohio, United States of America
| | - David S. Askew
- Department of Pathology & Laboratory Medicine, University of Cincinnati College of Medicine, Cincinnati, Ohio, United States of America
- * E-mail:
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García MTA, González ELM. Natural antioxidants protect against cadmium-induced damage during pregnancy and lactation in rats' pups. J Food Sci 2010; 75:R121-30. [PMID: 20492210 PMCID: PMC2995313 DOI: 10.1111/j.1750-3841.2010.01763.x] [Citation(s) in RCA: 81] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Advanced food processing methods that accomplish inactivation of microorganisms but minimize adverse thermal exposure are of great interest to the food industry. High pressure (HP) and pulsed electric field (PEF) processing are commercially applied to produce high quality fruit and vegetable products in the United States, Europe, and Japan. Both microbial and plant cell membranes are significantly altered following exposure to heat, HP, or PEF. Our research group sought to quantify the degree of damage to plant cell membranes that occurs as a result of exposure to heat, HP, or PEF, using the same analytical methods. In order to evaluate whether new advanced processing methods are superior to traditional thermal processing methods, it is necessary to compare them. In this review, we describe the existing state of knowledge related to effects of heat, HP, and PEF on both microbial and plant cells. The importance and relevance of compartmentalization in plant cells as it relates to fruit and vegetable quality is described and various methods for quantification of plant cell membrane integrity are discussed. These include electrolyte leakage, cell viability, and proton nuclear magnetic resonance (1H-NMR).
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Guyot S, Pottier L, Ferret E, Gal L, Gervais P. Physiological responses of Escherichia coli exposed to different heat-stress kinetics. Arch Microbiol 2010; 192:651-61. [PMID: 20549191 DOI: 10.1007/s00203-010-0597-1] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2010] [Revised: 05/26/2010] [Accepted: 05/31/2010] [Indexed: 11/28/2022]
Abstract
The effects of heat-stress kinetics on the viability of Escherichia coli were investigated. Cells were exposed to heat-stress treatments extending from 30 to 50 degrees C, with either a slope (40 min) or a shock (10 s), both followed by a 1-h plateau at 50 degrees C in nutritive medium. A higher survival rate was observed after the slope than after the shock, when both were followed by a plateau, so the heat slope induced a certain degree of thermotolerance. This tolerance was partly (i) linked to de novo protein synthesis during the subsequent plateau phase, and (ii) abolished after rapid cooling from 50 to 30 degrees C, which means that cellular components with rapidly reversible thermal properties are involved in this type of thermotolerance. The heat-slope-induced thermotolerance was chiefly linked to the maintenance of the plasma membrane integrity (preservation of structure, fluidity, and permeability), and not to GroEL or DnaK overexpression. Moreover, the high level of cell mortality induced by the heat shock could be related to changes in the membrane integrity.
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Affiliation(s)
- Stéphane Guyot
- Laboratoire de Génie des Procédés Microbiologiques et Alimentaires-AgroSup Dijon, Université de Bourgogne, 1 Esplanade Erasme, 21000 Dijon, France
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11
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Trofimova Y, Walker G, Rapoport A. Anhydrobiosis in yeast: influence of calcium and magnesium ions on yeast resistance to dehydration-rehydration. FEMS Microbiol Lett 2010; 308:55-61. [DOI: 10.1111/j.1574-6968.2010.01989.x] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
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12
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Keyhani E, Khavari-Nejad S, Keyhani J, Attar F. Acriflavine-Mediated Apoptosis and Necrosis in Yeast Candida utilis. Ann N Y Acad Sci 2009; 1171:284-91. [DOI: 10.1111/j.1749-6632.2009.04682.x] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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13
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Simonin H, Beney L, Gervais P. Controlling the membrane fluidity of yeasts during coupled thermal and osmotic treatments. Biotechnol Bioeng 2008; 100:325-33. [PMID: 18078293 DOI: 10.1002/bit.21749] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Yeasts are often exposed to variations in osmotic pressure in their natural environments or in their substrates when used in fermentation industries. Such changes may lead to cell death or activity loss. Previous work by our team has allowed us to relate the mortality of cells exposed to a combination of thermal and osmotic treatments to leakage of cellular components through an unstable membrane when lipid phase transition occurs. In this study, yeast viability was measured after numerous osmotic and thermal treatments. In addition, the fluidity of yeast membranes was assessed according to a(w) and temperature by means of 1,6-diphenyl-1,3,5-hexatriene (DPH) anisotropy measurement. The results show that there is a negative correlation between the overall fluidity variation undergone by membranes during treatments and yeast survival. Using a diagram of membrane fluidity according to a(w) and temperature, we defined dehydration and rehydration methods that minimize fluidity fluctuations, permitting significantly increased yeast survival. Thus, such membrane fluidity diagram should be a potential tool for controlling membrane state during dehydration and rehydration and improve yeast survival. Overall fluidity measurements should now be completed by accurate structural analysis of membranes to better understand the plasma membrane changes occurring during dehydration and rehydration.
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Affiliation(s)
- Hélène Simonin
- Laboratoire de Génie des Procédés Microbiologiques et Alimentaires, ENSBANA, Esplanade Erasme, 21000 Dijon, France
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Cao-Hoang L, Dumont F, Marechal PA, Le-Thanh M, Gervais P. Rates of chilling to 0°C: implications for the survival of microorganisms and relationship with membrane fluidity modifications. Appl Microbiol Biotechnol 2008; 77:1379-87. [DOI: 10.1007/s00253-007-1279-z] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2006] [Accepted: 11/06/2007] [Indexed: 11/29/2022]
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15
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Moussa M, Perrier-Cornet JM, Gervais P. Damage in Escherichia coli cells treated with a combination of high hydrostatic pressure and subzero temperature. Appl Environ Microbiol 2007; 73:6508-18. [PMID: 17766454 PMCID: PMC2075060 DOI: 10.1128/aem.01212-07] [Citation(s) in RCA: 63] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The relationship between membrane permeability, changes in ultrastructure, and inactivation in Escherichia coli strain K-12TG1 cells subjected to high hydrostatic pressure treatment at room and subzero temperatures was studied. Propidium iodide staining performed before and after pressure treatment made it possible to distinguish between reversible and irreversible pressure-mediated cell membrane permeabilization. Changes in cell ultrastructure were studied using transmission electron microscopy (TEM), which showed noticeable condensation of nucleoids and aggregation of cytosolic proteins in cells fixed after decompression. A novel technique used to mix fixation reagents with the cell suspension in situ under high hydrostatic pressure (HHP) and subzero-temperature conditions made it possible to show the partial reversibility of pressure-induced nucleoid condensation. However, based on visual examination of TEM micrographs, protein aggregation did not seem to be reversible. Reversible cell membrane permeabilization was noticeable, particularly for HHP treatments at subzero temperature. A correlation between membrane permeabilization and cell inactivation was established, suggesting different mechanisms at room and subzero temperatures. We propose that the inactivation of E. coli cells under combined HHP and subzero temperature occurs mainly during their transiently permeabilized state, whereas HHP inactivation at room temperature is related to a balance of transient and permanent permeabilization. The correlation between TEM results and cell inactivation was not absolute. Further work is required to elucidate the effects of pressure-induced damage on nucleoids and proteins during cell inactivation.
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Affiliation(s)
- Marwen Moussa
- Laboratoire de Génie des Procédés Microbiologiques et Alimentaires, ENSBANA, Université de Bourgogne, 1, Esplanade Erasme, 21000 Dijon, France
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