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Bravo-Ferrada B, Gonçalves S, Semorile L, Santos N, Tymczyszyn E, Hollmann A. Study of surface damage on cell envelope assessed by AFM and flow cytometry of Lactobacillus plantarum
exposed to ethanol and dehydration. J Appl Microbiol 2015; 118:1409-17. [DOI: 10.1111/jam.12796] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2014] [Revised: 03/03/2015] [Accepted: 03/05/2015] [Indexed: 11/28/2022]
Affiliation(s)
- B.M. Bravo-Ferrada
- Laboratorio de Microbiología Molecular; Instituto de Microbiología Básica y Aplicada (IMBA); Departamento de Ciencia y Tecnología; Universidad Nacional de Quilmes; Bernal Argentina
| | - S. Gonçalves
- Instituto de Medicina Molecular; Faculdade de Medicina; Universidade de Lisboa; Lisbon Portugal
| | - L. Semorile
- Laboratorio de Microbiología Molecular; Instituto de Microbiología Básica y Aplicada (IMBA); Departamento de Ciencia y Tecnología; Universidad Nacional de Quilmes; Bernal Argentina
| | - N.C. Santos
- Instituto de Medicina Molecular; Faculdade de Medicina; Universidade de Lisboa; Lisbon Portugal
| | - E.E. Tymczyszyn
- Laboratorio de Microbiología Molecular; Instituto de Microbiología Básica y Aplicada (IMBA); Departamento de Ciencia y Tecnología; Universidad Nacional de Quilmes; Bernal Argentina
- CONICET; Buenos Aires Argentina
| | - A. Hollmann
- Laboratorio de Microbiología Molecular; Instituto de Microbiología Básica y Aplicada (IMBA); Departamento de Ciencia y Tecnología; Universidad Nacional de Quilmes; Bernal Argentina
- Instituto de Medicina Molecular; Faculdade de Medicina; Universidade de Lisboa; Lisbon Portugal
- Laboratory of Biointerfaces and Biomimetic Systems; CITSE-University of Santiago del Estero-CONICET; Santiago del Estero Argentina
- CONICET; Buenos Aires Argentina
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52
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Koseki S, Nakamura N, Shiina T. Comparison of desiccation tolerance among Listeria monocytogenes, Escherichia coli O157:H7, Salmonella enterica, and Cronobacter sakazakii in powdered infant formula. J Food Prot 2015; 78:104-10. [PMID: 25581184 DOI: 10.4315/0362-028x.jfp-14-249] [Citation(s) in RCA: 57] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Bacterial pathogens such as Listeria monocytogenes, Escherichia coli O157:H7, Salmonella enterica, and Cronobacter sakazakii have demonstrated long-term survival in/on dry or low-water activity (aw) foods. However, there have been few comparative studies on the desiccation tolerance among these bacterial pathogens separately in a same food matrix. In the present study, the survival kinetics of the four bacterial pathogens separately inoculated onto powdered infant formula as a model low-aw food was compared during storage at 5, 22, and 35°C. No significant differences in the survival kinetics between E. coli O157:H7 and L. monocytogenes were observed. Salmonella showed significantly higher desiccation tolerance than these pathogens, and C. sakazakii demonstrated significantly higher desiccation tolerance than all other three bacteria studied. Thus, the desiccation tolerance was represented as C. sakazakii > Salmonella > E. coli O157:H7 = L. monocytogenes. The survival kinetics of each bacterium was mathematically analyzed, and the observed kinetics was successfully described using the Weibull model. To evaluate the variability of the inactivation kinetics of the tested bacterial pathogens, the Monte Carlo simulation was performed using assumed probability distribution of the estimated fitted parameters. The simulation results showed that the storage temperature significantly influenced survival of each bacterium under the dry environment, where the bacterial inactivation became faster with increasing storage temperature. Furthermore, the fitted rate and shape parameters of the Weibull model were successfully modelled as a function of temperature. The numerical simulation of the bacterial inactivation was realized using the functions of the parameters under arbitrary fluctuating temperature conditions.
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Affiliation(s)
- Shigenobu Koseki
- Research Faculty of Agriculture, Hokkaido University, Kita 9 Nishi 9, Kita-ku, Sapporo 060-8589, Japan; National Food Research Institute, 2-1-12 Kannondai, Tsukuba, Ibaraki 305-8642, Japan; Research Faculty of Agriculture, Hokkaido University, Kita 9 Nishi 9, Kita-ku, Sapporo 060-8589, Japan.
| | - Nobutaka Nakamura
- National Food Research Institute, 2-1-12 Kannondai, Tsukuba, Ibaraki 305-8642, Japan
| | - Takeo Shiina
- National Food Research Institute, 2-1-12 Kannondai, Tsukuba, Ibaraki 305-8642, Japan
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Bravo-Ferrada BM, Gómez-Zavaglia A, Semorile L, Tymczyszyn EE. Effect of the fatty acid composition of acclimated oenological Lactobacillus plantarum on the resistance to ethanol. Lett Appl Microbiol 2014; 60:155-161. [PMID: 25359087 DOI: 10.1111/lam.12350] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2014] [Revised: 10/22/2014] [Accepted: 10/27/2014] [Indexed: 11/28/2022]
Abstract
The aim of this work was to evaluate the changes due to acclimation to ethanol on the fatty acid composition of three oenological Lactobacillus plantarum strains and their effect on the resistance to ethanol and malic acid consumption (MAC). Lactobacillus plantarum UNQLp 133, UNQLp 65.3 and UNQLp 155 were acclimated in the presence of 6 or 10% v/v ethanol, for 48 h at 28°C. Lipids were extracted to obtain fatty acid methyl esters and analysed by gas chromatography interfaced with mass spectroscopy. The influence of change in fatty acid composition on the viability and MAC in synthetic wine was analysed by determining the Pearson correlation coefficient. Acclimated strains showed a significant change in the fatty composition with regard to the nonacclimated strains. Adaptation to ethanol led to a decrease in the unsaturated/saturated ratio, mainly resulting from an increase in the contribution of short-length fatty acid C12:0 and a decrease of C18:1. The content of C12:0 was related to a higher viability after inoculation of synthetic wine. The MAC increased at higher contents in saturated fatty acid, but its efficiency was strain dependent.
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Affiliation(s)
- B M Bravo-Ferrada
- Laboratorio de Microbiología Molecular, Departamento de Ciencia y Tecnología, Universidad Nacional de Quilmes, Bernal, Argentina
| | - A Gómez-Zavaglia
- Centro de Investigación y Desarrollo en Criotecnología de Alimentos (CIDCA) (CONICET La Plata, UNLP), La Plata, Argentina
| | - L Semorile
- Laboratorio de Microbiología Molecular, Departamento de Ciencia y Tecnología, Universidad Nacional de Quilmes, Bernal, Argentina
| | - E E Tymczyszyn
- Laboratorio de Microbiología Molecular, Departamento de Ciencia y Tecnología, Universidad Nacional de Quilmes, Bernal, Argentina
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Sanders ME, Klaenhammer TR, Ouwehand AC, Pot B, Johansen E, Heimbach JT, Marco ML, Tennilä J, Ross RP, Franz C, Pagé N, Pridmore RD, Leyer G, Salminen S, Charbonneau D, Call E, Lenoir-Wijnkoop I. Effects of genetic, processing, or product formulation changes on efficacy and safety of probiotics. Ann N Y Acad Sci 2014; 1309:1-18. [PMID: 24571253 DOI: 10.1111/nyas.12363] [Citation(s) in RCA: 61] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Commercial probiotic strains for food or supplement use can be altered in different ways for a variety of purposes. Production conditions for the strain or final product may be changed to address probiotic yield, functionality, or stability. Final food products may be modified to improve flavor and other sensory properties, provide new product formats, or respond to market opportunities. Such changes can alter the expression of physiological traits owing to the live nature of probiotics. In addition, genetic approaches may be used to improve strain attributes. This review explores whether genetic or phenotypic changes, by accident or design, might affect the efficacy or safety of commercial probiotics. We highlight key issues important to determining the need to re-confirm efficacy or safety after strain improvement, process optimization, or product formulation changes. Research pinpointing the mechanisms of action for probiotic function and the development of assays to measure them are greatly needed to better understand if such changes have a substantive impact on probiotic efficacy.
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Affiliation(s)
- Mary Ellen Sanders
- International Scientific Association for Probiotics and Prebiotics, Centennial, Colorado
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Bang M, Oh S, Lim KS, Kim Y, Oh S. The involvement of ATPase activity in the acid tolerance ofLactobacillus rhamnosusstrain GG. INT J DAIRY TECHNOL 2014. [DOI: 10.1111/1471-0307.12123] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Affiliation(s)
- Miseon Bang
- Division of Animal Science; Institute of Agricultural Science and Technology; Chonnam National University; Gwangju 500-757 Korea
| | - Sangnam Oh
- BK21 Plus Graduate Program; Department of Animal Science and Institute of Rare Earth for Biological Application; Chonbuk National University; Jeonju 561-756 Korea
| | - Kwang-Sei Lim
- R & D Ctr.; Maeil Dairy Co. Ltd; Pyeongtaek 451-861 Korea
| | - Younghoon Kim
- BK21 Plus Graduate Program; Department of Animal Science and Institute of Rare Earth for Biological Application; Chonbuk National University; Jeonju 561-756 Korea
| | - Sejong Oh
- Division of Animal Science; Institute of Agricultural Science and Technology; Chonnam National University; Gwangju 500-757 Korea
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Adaptation of the wine bacterium Oenococcus oeni to ethanol stress: role of the small heat shock protein Lo18 in membrane integrity. Appl Environ Microbiol 2014; 80:2973-80. [PMID: 24584255 DOI: 10.1128/aem.04178-13] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Malolactic fermentation in wine is often carried out by Oenococcus oeni. Wine is a stressful environment for bacteria because ethanol is a toxic compound that impairs the integrity of bacterial membranes. The small heat shock protein (sHsp) Lo18 is an essential actor of the stress response in O. oeni. Lo18 prevents the thermal aggregation of proteins and plays a crucial role in membrane quality control. Here, we investigated the interaction between Lo18 and four types of liposomes: one was prepared from O. oeni grown under optimal growth conditions (here, control liposomes), one was prepared from O. oeni grown in the presence of 8% ethanol (here, ethanol liposomes), one was prepared from synthetic phospholipids, and one was prepared from phospholipids from Bacillus subtilis or Lactococcus lactis. We observed the strongest interaction between Lo18 and control liposomes. The lipid binding activity of Lo18 required the dissociation of oligomeric structures into dimers. Protein protection experiments carried out in the presence of the liposomes from O. oeni suggested that Lo18 had a higher affinity for control liposomes than for a model protein. In anisotropy experiments, we mimicked ethanol action by temperature-dependent fluidization of the liposomes. Results suggest that the principal determinant of Lo18-membrane interaction is lipid bilayer phase behavior rather than phospholipid composition. We suggest a model to describe the ethanol adaptation of O. oeni. This model highlights the dual role of Lo18 in the protection of proteins from aggregation and membrane stabilization and suggests how modifications of phospholipid content may be a key factor determining the balance between these two functions.
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57
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Engineering biofuel tolerance in non-native producing microorganisms. Biotechnol Adv 2014; 32:541-8. [PMID: 24530635 DOI: 10.1016/j.biotechadv.2014.02.001] [Citation(s) in RCA: 57] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2013] [Revised: 01/19/2014] [Accepted: 02/08/2014] [Indexed: 01/17/2023]
Abstract
Large-scale production of renewable biofuels through microbiological processes has drawn significant attention in recent years, mostly due to the increasing concerns on the petroleum fuel shortages and the environmental consequences of the over-utilization of petroleum-based fuels. In addition to native biofuel-producing microbes that have been employed for biofuel production for decades, recent advances in metabolic engineering and synthetic biology have made it possible to produce biofuels in several non-native biofuel-producing microorganisms. Compared to native producers, these non-native systems carry the advantages of fast growth, simple nutrient requirements, readiness for genetic modifications, and even the capability to assimilate CO2 and solar energy, making them competitive alternative systems to further decrease the biofuel production cost. However, the tolerance of these non-native microorganisms to toxic biofuels is naturally low, which has restricted the potentials of their application for high-efficiency biofuel production. To address the issues, researches have been recently conducted to explore the biofuel tolerance mechanisms and to construct robust high-tolerance strains for non-native biofuel-producing microorganisms. In this review, we critically summarize the recent progress in this area, focusing on three popular non-native biofuel-producing systems, i.e. Escherichia coli, Lactobacillus and photosynthetic cyanobacteria.
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58
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Safety of the surrogate microorganism Enterococcus faecium NRRL B-2354 for use in thermal process validation. Appl Environ Microbiol 2014; 80:1899-909. [PMID: 24413604 DOI: 10.1128/aem.03859-13] [Citation(s) in RCA: 83] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Enterococcus faecium NRRL B-2354 is a surrogate microorganism used in place of pathogens for validation of thermal processing technologies and systems. We evaluated the safety of strain NRRL B-2354 based on its genomic and functional characteristics. The genome of E. faecium NRRL B-2354 was sequenced and found to comprise a 2,635,572-bp chromosome and a 214,319-bp megaplasmid. A total of 2,639 coding sequences were identified, including 45 genes unique to this strain. Hierarchical clustering of the NRRL B-2354 genome with 126 other E. faecium genomes as well as pbp5 locus comparisons and multilocus sequence typing (MLST) showed that the genotype of this strain is most similar to commensal, or community-associated, strains of this species. E. faecium NRRL B-2354 lacks antibiotic resistance genes, and both NRRL B-2354 and its clonal relative ATCC 8459 are sensitive to clinically relevant antibiotics. This organism also lacks, or contains nonfunctional copies of, enterococcal virulence genes including acm, cyl, the ebp operon, esp, gelE, hyl, IS16, and associated phenotypes. It does contain scm, sagA, efaA, and pilA, although either these genes were not expressed or their roles in enterococcal virulence are not well understood. Compared with the clinical strains TX0082 and 1,231,502, E. faecium NRRL B-2354 was more resistant to acidic conditions (pH 2.4) and high temperatures (60°C) and was able to grow in 8% ethanol. These findings support the continued use of E. faecium NRRL B-2354 in thermal process validation of food products.
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Van Bokhorst-van de Veen H, Bongers RS, Wels M, Bron PA, Kleerebezem M. Transcriptome signatures of class I and III stress response deregulation in Lactobacillus plantarum reveal pleiotropic adaptation. Microb Cell Fact 2013; 12:112. [PMID: 24238744 PMCID: PMC3842655 DOI: 10.1186/1475-2859-12-112] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2013] [Accepted: 11/11/2013] [Indexed: 01/17/2023] Open
Abstract
Background To cope with environmental challenges bacteria possess sophisticated defense mechanisms that involve stress-induced adaptive responses. The canonical stress regulators CtsR and HrcA play a central role in the adaptations to a plethora of stresses in a variety of organisms. Here, we determined the CtsR and HrcA regulons of the lactic acid bacterium Lactobacillus plantarum WCFS1 grown under reference (28°C) and elevated (40°C) temperatures, using ctsR, hrcA, and ctsR-hrcA deletion mutants. Results While the maximum specific growth rates of the mutants and the parental strain were similar at both temperatures (0.33 ± 0.02 h-1 and 0.34 ± 0.03 h-1, respectively), DNA microarray analyses revealed that the CtsR or HrcA deficient strains displayed altered transcription patterns of genes encoding functions involved in transport and binding of sugars and other compounds, primary metabolism, transcription regulation, capsular polysaccharide biosynthesis, as well as fatty acid metabolism. These transcriptional signatures enabled the refinement of the gene repertoire that is directly or indirectly controlled by CtsR and HrcA of L. plantarum. Deletion of both regulators, elicited transcriptional changes of a large variety of additional genes in a temperature-dependent manner, including genes encoding functions involved in cell-envelope remodeling. Moreover, phenotypic assays revealed that both transcription regulators contribute to regulation of resistance to hydrogen peroxide stress. The integration of these results allowed the reconstruction of CtsR and HrcA regulatory networks in L. plantarum, highlighting the significant intertwinement of class I and III stress regulons. Conclusions Taken together, our results enabled the refinement of the CtsR and HrcA regulatory networks in L. plantarum, illustrating the complex nature of adaptive stress responses in this bacterium.
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Bravo-Ferrada BM, Tymczyszyn EE, Gómez-Zavaglia A, Semorile L. Effect of acclimation medium on cell viability, membrane integrity and ability to consume malic acid in synthetic wine by oenological Lactobacillus plantarum strains. J Appl Microbiol 2013; 116:360-7. [PMID: 24224840 DOI: 10.1111/jam.12372] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2013] [Revised: 09/29/2013] [Accepted: 10/21/2013] [Indexed: 11/26/2022]
Abstract
AIMS The aim of this work was to evaluate the effect of acclimation on the viability, membrane integrity and the ability to consume malic acid of three oenological strains of Lactobacillus plantarum. METHODS AND RESULTS Cultures in the stationary phase were inoculated in an acclimation medium (Accl.) containing 0, 6 or 10% v/v ethanol and incubated 48 h at 28°C. After incubation, cells were harvested by centrifugation and inoculated in a synthetic wine, containing 14% v/v ethanol and pH 3.5 at 28°C. Viability and membrane integrity were determined by flow cytometry (FC) using carboxyfluorescein diacetate (cFDA) and propidium iodide. Bacterial growth and malic acid consumption were monitored in a synthetic wine during 15 days. In nonacclimated strains, the damage of bacterial membranes produced a dramatic decrease in microbial viability in synthetic wine. In contrast, survival of strains previously acclimated in Accl. with 6 and 10% v/v ethanol was noticeable higher. Therefore, acclimation with ethanol increased the cultivability in synthetic wine and consequently, the consumption of l-malic acid after 15 days of growth. CONCLUSION Acclimation of oenological strains in media containing ethanol prior to wine inoculation significantly decreases the membrane damage and improves viability in the harsh wine conditions. The role of membrane integrity is crucial to warrant the degradation of l-malic acid. SIGNIFICANCE AND IMPACT OF THE STUDY The efficiency of multiparametric FC in monitoring viability and membrane damage along with the malic acid consumption has a strong impact on winemaking because it represents a useful tool for a quick and highly reliable evaluation of oenological parameters.
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Affiliation(s)
- B M Bravo-Ferrada
- Laboratorio de Microbiología Molecular, Departamento de Ciencia y Tecnología, Universidad Nacional de Quilmes, Bernal, Argentina
| | - E E Tymczyszyn
- Centro de Investigación y Desarrollo en Criotecnología de Alimentos (CIDCA) (CONICET La Plata, UNLP), La Plata, Argentina
| | - A Gómez-Zavaglia
- Centro de Investigación y Desarrollo en Criotecnología de Alimentos (CIDCA) (CONICET La Plata, UNLP), La Plata, Argentina
| | - L Semorile
- Laboratorio de Microbiología Molecular, Departamento de Ciencia y Tecnología, Universidad Nacional de Quilmes, Bernal, Argentina
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61
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From physiology to systems metabolic engineering for the production of biochemicals by lactic acid bacteria. Biotechnol Adv 2013; 31:764-88. [DOI: 10.1016/j.biotechadv.2013.03.011] [Citation(s) in RCA: 109] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2012] [Revised: 03/28/2013] [Accepted: 03/31/2013] [Indexed: 11/21/2022]
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62
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Chu-Ky S, Bui TK, Nguyen TL, Ho PH. Acid adaptation to improve viability and X-prolyl dipeptidyl aminopeptidase activity of the probiotic bacteriumLactobacillus fermentumHA6 exposed to simulated gastrointestinal tract conditions. Int J Food Sci Technol 2013. [DOI: 10.1111/ijfs.12338] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Affiliation(s)
- Son Chu-Ky
- Department of Food Technology; School of Biotechnology and Food Technology; Hanoi University of Science and Technology; 1 Dai Co Viet, Hai Ba Trung Hanoi 10000 Vietnam
| | - Thi-Khanh Bui
- Department of Food Technology; School of Biotechnology and Food Technology; Hanoi University of Science and Technology; 1 Dai Co Viet, Hai Ba Trung Hanoi 10000 Vietnam
| | - Tien-Long Nguyen
- Department of Food Technology; School of Biotechnology and Food Technology; Hanoi University of Science and Technology; 1 Dai Co Viet, Hai Ba Trung Hanoi 10000 Vietnam
| | - Phu-Ha Ho
- Department of Food Technology; School of Biotechnology and Food Technology; Hanoi University of Science and Technology; 1 Dai Co Viet, Hai Ba Trung Hanoi 10000 Vietnam
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63
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ESR spin trapping for characterization of radical formation in Lactobacillus acidophilus NCFM and Listeria innocua. J Microbiol Methods 2013; 94:205-12. [DOI: 10.1016/j.mimet.2013.06.010] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2013] [Revised: 06/10/2013] [Accepted: 06/10/2013] [Indexed: 01/13/2023]
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64
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Transcriptome-based characterization of interactions between Saccharomyces cerevisiae and Lactobacillus delbrueckii subsp. bulgaricus in lactose-grown chemostat cocultures. Appl Environ Microbiol 2013; 79:5949-61. [PMID: 23872557 DOI: 10.1128/aem.01115-13] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Mixed populations of Saccharomyces cerevisiae yeasts and lactic acid bacteria occur in many dairy, food, and beverage fermentations, but knowledge about their interactions is incomplete. In the present study, interactions between Saccharomyces cerevisiae and Lactobacillus delbrueckii subsp. bulgaricus, two microorganisms that co-occur in kefir fermentations, were studied during anaerobic growth on lactose. By combining physiological and transcriptome analysis of the two strains in the cocultures, five mechanisms of interaction were identified. (i) Lb. delbrueckii subsp. bulgaricus hydrolyzes lactose, which cannot be metabolized by S. cerevisiae, to galactose and glucose. Subsequently, galactose, which cannot be metabolized by Lb. delbrueckii subsp. bulgaricus, is excreted and provides a carbon source for yeast. (ii) In pure cultures, Lb. delbrueckii subsp. bulgaricus grows only in the presence of increased CO2 concentrations. In anaerobic mixed cultures, the yeast provides this CO2 via alcoholic fermentation. (iii) Analysis of amino acid consumption from the defined medium indicated that S. cerevisiae supplied alanine to the bacterium. (iv) A mild but significant low-iron response in the yeast transcriptome, identified by DNA microarray analysis, was consistent with the chelation of iron by the lactate produced by Lb. delbrueckii subsp. bulgaricus. (v) Transcriptome analysis of Lb. delbrueckii subsp. bulgaricus in mixed cultures showed an overrepresentation of transcripts involved in lipid metabolism, suggesting either a competition of the two microorganisms for fatty acids or a response to the ethanol produced by S. cerevisiae. This study demonstrates that chemostat-based transcriptome analysis is a powerful tool to investigate microbial interactions in mixed populations.
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Genetic and physiological responses of Bifidobacterium animalis subsp. lactis to hydrogen peroxide stress. J Bacteriol 2013; 195:3743-51. [PMID: 23772066 DOI: 10.1128/jb.00279-13] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Consumer interest in probiotic bifidobacteria is increasing, but industry efforts to secure high cell viability in foods is undermined by these anaerobes' sensitivity to oxidative stress. To address this limitation, we investigated genetic and physiological responses of two fully sequenced Bifidobacterium animalis subsp. lactis strains, BL-04 and DSM 10140, to hydrogen peroxide (H₂O₂) stress. Although the genome sequences for these strains are highly clonal, prior work showed that they differ in both intrinsic and inducible H₂O₂ resistance. Transcriptome analysis of early-stationary-phase cells exposed to a sublethal H₂O₂ concentration detected significant (P < 0.05) changes in expression of 138 genes in strain BL-04 after 5 min and 27 genes after 20 min. Surprisingly, no significant changes in gene expression were detected in DSM 10140 at either time. Genomic data suggested that differences in H₂O₂ stress resistance might be due to a mutation in a BL-04 gene encoding long-chain fatty acid coenzyme A (CoA) ligase. To explore this possibility, membrane fatty acids were isolated and analyzed by gas chromatography-mass spectrometry (GC-MS). Results confirmed that the strains had significantly different lipid profiles: the BL-04 membrane contained higher percentages of C(14:0) and C(16:0) and lower percentages of C(18:1n9). Alteration of the DSM 10140 membrane lipid composition using modified growth medium to more closely mimic that of BL-04 yielded cells that showed increased intrinsic resistance to lethal H₂O₂ challenge but did not display an inducible H₂O₂ stress response. The results show that deliberate stress induction or membrane lipid modification can be employed to significantly improve H₂O₂ resistance in B. animalis subsp. lactis strains.
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Identification of critical genes for growth in olive brine by transposon mutagenesis of Lactobacillus pentosus C11. Appl Environ Microbiol 2013; 79:4568-75. [PMID: 23686273 DOI: 10.1128/aem.01159-13] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Olive brine represents a stressful environment due to the high NaCl concentration, presence of phenolic compounds known as antimicrobials, and low availability of nutrients. Thus, only a few strains of lactic acid bacteria (LAB) are adapted to grow in and ferment table olives. To identify the mechanisms by which these few strains are able to grow in olive brine, Lactobacillus pentosus C11, a particularly resistant strain isolated from naturally fermented table olives, was mutagenized by random transposition using the P(junc)-TpaseIS1223 system (H. Licandro-Seraut, S. Brinster, M. van de Guchte, H. Scornec, E. Maguin, P. Sansonetti, J. F. Cavin, and P. Serror, Appl. Environ. Microbiol. 78:5417-5423, 2012). A library of 6,000 mutants was generated and screened for adaptation and subsequent growth in a medium, named BSM (brine screening medium), which presents the stressful conditions encountered in olive brine. Five transposition mutants impaired in growth on BSM were identified. Transposition occurred in two open reading frames and in three transcription terminators affecting stability of transcripts. Thus, several essential genes for adaptation and growth of L. pentosus C11 in olive brine were identified.
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Adaptation of the hydrocarbonoclastic bacterium Alcanivorax borkumensis SK2 to alkanes and toxic organic compounds: a physiological and transcriptomic approach. Appl Environ Microbiol 2013; 79:4282-93. [PMID: 23645199 DOI: 10.1128/aem.00694-13] [Citation(s) in RCA: 58] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
The marine hydrocarbonoclastic bacterium Alcanivorax borkumensis is able to degrade mixtures of n-alkanes as they occur in marine oil spills. However, investigations of growth behavior and physiology of these bacteria when cultivated with n-alkanes of different chain lengths (C6 to C30) as the substrates are still lacking. Growth rates increased with increasing alkane chain length up to a maximum between C12 and C19, with no evident difference between even- and odd-numbered chain lengths, before decreasing with chain lengths greater than C19. Surface hydrophobicity of alkane-grown cells, assessed by determination of the water contact angles, showed a similar pattern, with maximum values associated with growth rates on alkanes with chain lengths between C11 and C19 and significantly lower values for cells grown on pyruvate. A. borkumensis was found to incorporate and modify the fatty acid intermediates generated by the corresponding n-alkane degradation pathway. Cells grown on distinct n-alkanes proved that A. borkumensis is able to not only incorporate but also modify fatty acid intermediates derived from the alkane degradation pathway. Comparing cells grown on pyruvate with those cultivated on hexadecane in terms of their tolerance toward two groups of toxic organic compounds, chlorophenols and alkanols, representing intensely studied organic compounds, revealed similar tolerances toward chlorophenols, whereas the toxicities of different n-alkanols were significantly reduced when hexadecane was used as a carbon source. As one adaptive mechanism of A. borkumensis to these toxic organic solvents, the activity of cis-trans isomerization of unsaturated fatty acids was proven. These findings could be verified by a detailed transcriptomic comparison between cultures grown on hexadecane and pyruvate and including solvent stress caused by the addition of 1-octanol as the most toxic intermediate of n-alkane degradation.
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Zhang Y, Li Y. Engineering the antioxidative properties of lactic acid bacteria for improving its robustness. Curr Opin Biotechnol 2013; 24:142-7. [DOI: 10.1016/j.copbio.2012.08.013] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2012] [Revised: 08/22/2012] [Accepted: 08/30/2012] [Indexed: 10/27/2022]
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Reverón I, de Las Rivas B, Muñoz R, López de Felipe F. Genome-wide transcriptomic responses of a human isolate of Lactobacillus plantarum exposed to p-coumaric acid stress. Mol Nutr Food Res 2012; 56:1848-59. [PMID: 23065750 DOI: 10.1002/mnfr.201200384] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2012] [Revised: 08/20/2012] [Accepted: 09/03/2012] [Indexed: 11/12/2022]
Abstract
SCOPE To advance knowledge of the stress tolerance mechanisms of a probiotic Lactobacillus plantarum strain to dietary hydroxycinnamic acids and the role of gut commensal microorganisms in the bioactivation of polyphenols. METHODS AND RESULTS To understand how gut commensal microorganisms tolerate toxicity of hydroxycinnamic acids and bioactivate these compounds, we used whole genome transcriptional profiling to characterize the response of a L. plantarum human isolate during challenge with p-coumaric acid (p-CA). The transcriptional profile reveals a massive induction of genes involved in stress resistance and detoxification-related functions and a global shutdown of growth-associated processes. A specific oxidative stress response, including a large reshape of nitrogen metabolism toward methionine production, was induced, probably to counteract a p-CA-induced oxidative protein stress. The transcriptional datasets revealed overlapping behaviors with the response of L. plantarum to the gut environment. CONCLUSION Contact with p-CA triggers responses that would be potentially beneficial for the intestinal function such as detoxification of dietary hydroxycinnamic acids and induction of a marked antioxidant response. Elicited responses indicated that contact with p-CA could provide preparedness to L. plantarum for adaptation to the gut environment. This knowledge facilitates the way to design methods to improve probiotic cell survival in this habitat.
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Affiliation(s)
- Inés Reverón
- Laboratorio de Biotecnología Bacteriana, Instituto de Ciencia y Tecnología de los Alimentos y Nutrición (ICTAN-CSIC), Madrid, Spain
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van Bokhorst-van de Veen H, van Swam I, Wels M, Bron PA, Kleerebezem M. Congruent strain specific intestinal persistence of Lactobacillus plantarum in an intestine-mimicking in vitro system and in human volunteers. PLoS One 2012; 7:e44588. [PMID: 22970257 PMCID: PMC3435264 DOI: 10.1371/journal.pone.0044588] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2012] [Accepted: 08/08/2012] [Indexed: 01/17/2023] Open
Abstract
Background An important trait of probiotics is their capability to reach their intestinal target sites alive to optimally exert their beneficial effects. Assessment of this trait in intestine-mimicking in vitro model systems has revealed differential survival of individual strains of a species. However, data on the in situ persistence characteristics of individual or mixtures of strains of the same species in the gastrointestinal tract of healthy human volunteers have not been reported to date. Methodology/Principal Findings The GI-tract survival of individual L. plantarum strains was determined using an intestine mimicking model system, revealing substantial inter-strain differences. The obtained data were correlated to genomic diversity of the strains using comparative genome hybridization (CGH) datasets, but this approach failed to discover specific genetic loci that explain the observed differences between the strains. Moreover, we developed a next-generation sequencing-based method that targets a variable intergenic region, and employed this method to assess the in vivo GI-tract persistence of different L. plantarum strains when administered in mixtures to healthy human volunteers. Remarkable consistency of the strain-specific persistence curves were observed between individual volunteers, which also correlated significantly with the GI-tract survival predicted on basis of the in vitro assay. Conclusion The survival of individual L. plantarum strains in the GI-tract could not be correlated to the absence or presence of specific genes compared to the reference strain L. plantarum WCFS1. Nevertheless, in vivo persistence analysis in the human GI-tract confirmed the strain-specific persistence, which appeared to be remarkably similar in different healthy volunteers. Moreover, the relative strain-specific persistence in vivo appeared to be accurately and significantly predicted by their relative survival in the intestine-mimicking in vitro assay, supporting the use of this assay for screening of strain-specific GI persistence.
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Affiliation(s)
- Hermien van Bokhorst-van de Veen
- TI Food & Nutrition, Wageningen, The Netherlands
- NIZO food research, Ede, The Netherlands
- Laboratory of Microbiology, Wageningen University and Research Centre, Wageningen, The Netherlands
| | - Iris van Swam
- TI Food & Nutrition, Wageningen, The Netherlands
- NIZO food research, Ede, The Netherlands
| | - Michiel Wels
- TI Food & Nutrition, Wageningen, The Netherlands
- NIZO food research, Ede, The Netherlands
- Centre for Molecular and Biomolecular Informatics (CMBI 260), Radboud University Medical Centre, Nijmegen, The Netherlands
| | - Peter A. Bron
- TI Food & Nutrition, Wageningen, The Netherlands
- NIZO food research, Ede, The Netherlands
- Kluyver Centre for Genomics of Industrial Fermentation, Delft, The Netherlands
- * E-mail:
| | - Michiel Kleerebezem
- TI Food & Nutrition, Wageningen, The Netherlands
- NIZO food research, Ede, The Netherlands
- Laboratory of Microbiology, Wageningen University and Research Centre, Wageningen, The Netherlands
- Host-Microbe Interactomics, Wageningen University and Research Centre, Wageningen, The Netherlands
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Genome sequences of the ethanol-tolerant Lactobacillus vini strains LMG 23202T and JP7.8.9. J Bacteriol 2012; 194:3018. [PMID: 22582376 DOI: 10.1128/jb.00446-12] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
We report on the genome sequences of Lactobacillus vini type strain LMG 23202(T) (DSM 20605) (isolated from fermenting grape musts in Spain) and the industrial strain L. vini JP7.8.9 (isolated from a bioethanol plant in northeast Brazil). All contigs were assembled using gsAssembler, and genes were predicted and annotated using Rapid Annotation using Subsystem Technology (RAST). The identified genome sequence of LMG 23202(T) had 2.201.333 bp, 37.6% G+C, and 1,833 genes, whereas the identified genome sequence of JP7.8.9 had 2.301.037 bp, 37.8% G+C, and 1,739 genes. The gene repertoire of the species L. vini offers promising opportunities for biotechnological applications.
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Modulation of Lactobacillus plantarum gastrointestinal robustness by fermentation conditions enables identification of bacterial robustness markers. PLoS One 2012; 7:e39053. [PMID: 22802934 PMCID: PMC3389004 DOI: 10.1371/journal.pone.0039053] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2012] [Accepted: 05/14/2012] [Indexed: 01/01/2023] Open
Abstract
Background Lactic acid bacteria (LAB) are applied worldwide in the production of a variety of fermented food products. Additionally, specific Lactobacillus species are nowadays recognized for their health-promoting effects on the consumer. To optimally exert such beneficial effects, it is considered of great importance that these probiotic bacteria reach their target sites in the gut alive. Methodology/Principal Findings In the accompanying manuscript by Bron et al. the probiotic model organism Lactobacillus plantarum WCFS1 was cultured under different fermentation conditions, which was complemented by the determination of the corresponding molecular responses by full-genome transcriptome analyses. Here, the gastrointestinal (GI) survival of the cultures produced was assessed in an in vitro assay. Variations in fermentation conditions led to dramatic differences in GI-tract survival (up to 7-log) and high robustness could be associated with low salt and low pH during the fermentations. Moreover, random forest correlation analyses allowed the identification of specific transcripts associated with robustness. Subsequently, the corresponding genes were targeted by genetic engineering, aiming to enhance robustness, which could be achieved for 3 of the genes that negatively correlated with robustness and where deletion derivatives displayed enhanced survival compared to the parental strain. Specifically, a role in GI-tract survival could be confirmed for the lp_1669-encoded AraC-family transcription regulator, involved in capsular polysaccharide remodeling, the penicillin-binding protein Pbp2A involved in peptidoglycan biosynthesis, and the Na+/H+ antiporter NapA3. Moreover, additional physiological analysis established a role for Pbp2A and NapA3 in bile salt and salt tolerance, respectively. Conclusion Transcriptome trait matching enabled the identification of biomarkers for bacterial (gut-)robustness, which is important for our molecular understanding of GI-tract survival and could facilitate the design of culture conditions aimed to enhance probiotic culture robustness.
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Seydlová G, Halada P, Fišer R, Toman O, Ulrych A, Svobodová J. DnaK and GroEL chaperones are recruited to the Bacillus subtilis membrane after short-term ethanol stress. J Appl Microbiol 2012; 112:765-74. [DOI: 10.1111/j.1365-2672.2012.05238.x] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
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Abstract
CtsR is an important repressor that modulates the transcription of class III stress genes in Gram-positive bacteria. In Bacillus subtilis, a model Gram-positive organism, the DNA binding activity of CtsR is regulated by McsAB-mediated phosphorylation of the protein where phosphorylated CtsR is a substrate for degradation by the ClpCP complex. Surprisingly, the mcsAB genes are absent from many Gram-positive bacteria, including streptococci; therefore, how CtsR activity is modulated in those bacteria remains unknown. Here we show that the posttranslational modulation of CtsR activity is different in Streptococcus mutans, a dental pathogen. We observed that of all of the Clp-related proteins, only ClpL is involved in the degradation of CtsR. Neither ClpP nor ClpC had any effect on the degradation of CtsR. We also found that phosphorylation of CtsR on a conserved arginine residue within the winged helix-turn-helix domain is necessary for modulation of the repressor activity of CtsR, as demonstrated by both in vitro and in vivo assays. We speculate that CtsR is regulated posttranslationally by a different mechanism in S. mutans and possibly in other streptococci.
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