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Lauková A, Maďar M, Zábolyová N, Troscianczyk A, Pogány Simonová M. Fortification of Goat Milk Yogurts with Encapsulated Postbiotic Active Lactococci. Life (Basel) 2024; 14:1147. [PMID: 39337930 PMCID: PMC11433272 DOI: 10.3390/life14091147] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2024] [Revised: 09/02/2024] [Accepted: 09/04/2024] [Indexed: 09/30/2024] Open
Abstract
The species Lactococcus lactis is a bacterium extensively used in the dairy industry. This bacterium is Generally Recognized as Safe and was added to the European Food Safety Authority's Qualified Presumption of Safety list. The major functions of this species in dairy fermentation are the production of lactic acid from lactose, citric acid fermentation, and the hydrolysis of casein. But, the representatives of this species that produce bacteriocin substances can also exert an inhibitory effect against spoilage bacteria. The aims of this study were to test three lactococcal strains isolated from raw goat milk for their postbiotic activity and to test their stability in goat milk yogurts after their application in encapsulated form for their further application. To achieve these aims, validated methods were used. Three Lactococcus lactis strains (identified by Blastn 16S rRNA analysis) produced bacteriocin substances/postbiotics. These concentrated postbiotics inhibited the growth of enterococci and staphylococci (by up to 97.8%), reaching an inhibitory activity of up to 800 AU/mL. The encapsulated (freeze-dried) lactococci survived in the goat milk yogurts with sufficient stability. Strain MK2/8 fortified the yogurts in the highest amount (8.1 ± 0.0 cfu/g log 10). It did not influence the pH of the yogurt.
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Affiliation(s)
- Andrea Lauková
- Centre of Biosciences of the Slovak Academy of Sciences, Institute of Animal Physiology, Šoltésovej 4-6, 040 01 Košice, Slovakia; (N.Z.); (M.P.S.)
| | - Marián Maďar
- Department of Microbiology and Immunology, University of Veterinary Medicine and Pharmacy in Košice, Komenského 73, 041 84 Košice, Slovakia;
| | - Natália Zábolyová
- Centre of Biosciences of the Slovak Academy of Sciences, Institute of Animal Physiology, Šoltésovej 4-6, 040 01 Košice, Slovakia; (N.Z.); (M.P.S.)
| | - Aleksandra Troscianczyk
- Sub-Department of Veterinary Microbiology, Faculty of Veterinary Medicine, University of Life Sciences in Lublin, Akademicka Street 12, 20 950 Lublin, Poland;
| | - Monika Pogány Simonová
- Centre of Biosciences of the Slovak Academy of Sciences, Institute of Animal Physiology, Šoltésovej 4-6, 040 01 Košice, Slovakia; (N.Z.); (M.P.S.)
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Mohamed HM, Barzideh Z, Siddiqi M, LaPointe G. Taxonomy, Sequence Variance and Functional Profiling of the Microbial Community of Long-Ripened Cheddar Cheese Using Shotgun Metagenomics. Microorganisms 2023; 11:2052. [PMID: 37630612 PMCID: PMC10458550 DOI: 10.3390/microorganisms11082052] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2023] [Revised: 07/16/2023] [Accepted: 07/27/2023] [Indexed: 08/27/2023] Open
Abstract
Shotgun metagenomic sequencing was used to investigate the diversity of the microbial community of Cheddar cheese ripened over 32 months. The changes in taxa abundance were compared from assembly-based, non-assembly-based, and mOTUs2 sequencing pipelines to delineate the community profile for each age group. Metagenomic assembled genomes (MAGs) passing the quality threshold were obtained for 11 species from 58 samples. Although Lactococcus cremoris and Lacticaseibacillus paracasei were dominant across the shotgun samples, other species were identified using MG-RAST. NMDS analysis of the beta diversity of the microbial community revealed the similarity of the cheeses in older age groups (7 months to 32 months). As expected, the abundance of Lactococcus cremoris consistently decreased over ripening, while the proportion of permeable cells increased. Over the ripening period, the relative abundance of viable Lacticaseibacillus paracasei progressively increased, but at a variable rate among trials. Reads attributed to Siphoviridae and Ascomycota remained below 1% relative abundance. The functional profiles of PMA-treated cheeses differed from those of non-PMA-treated cheeses. Starter rotation was reflected in the single nucleotide variant profiles of Lactococcus cremoris (SNVs of this species using mOTUs2), while the incoming milk was the leading factor in discriminating Lacticaseibacillus paracasei/casei SNV profiles. The relative abundance estimates from Kraken2, non-assembly-based (MG-RAST) and marker gene clusters (mOTUs2) were consistent across age groups for the two dominant taxa. Metagenomics enabled sequence variant analysis below the bacterial species level and functional profiling that may affect the metabolic interactions between subpopulations in cheese during ripening, which could help explain the overall flavour development of cheese. Future work will integrate microbial variants with volatile profiles to associate the development of compounds related to cheese flavour at each ripening stage.
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Affiliation(s)
- Hassan Mahmoud Mohamed
- Dairy at Guelph, Department of Food Science, University of Guelph, Guelph, ON N1G 2W1, Canada
- Faculty of Computer and Artificial Intelligence, Benha University, Banha 13518, Egypt
| | - Zoha Barzideh
- Dairy at Guelph, Department of Food Science, University of Guelph, Guelph, ON N1G 2W1, Canada
| | - Myra Siddiqi
- Dairy at Guelph, Department of Food Science, University of Guelph, Guelph, ON N1G 2W1, Canada
| | - Gisèle LaPointe
- Dairy at Guelph, Department of Food Science, University of Guelph, Guelph, ON N1G 2W1, Canada
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Anastasiou R, Kazou M, Georgalaki M, Aktypis A, Zoumpopoulou G, Tsakalidou E. Omics Approaches to Assess Flavor Development in Cheese. Foods 2022; 11:188. [PMID: 35053920 PMCID: PMC8775153 DOI: 10.3390/foods11020188] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2021] [Revised: 01/03/2022] [Accepted: 01/09/2022] [Indexed: 12/27/2022] Open
Abstract
Cheese is characterized by a rich and complex microbiota that plays a vital role during both production and ripening, contributing significantly to the safety, quality, and sensory characteristics of the final product. In this context, it is vital to explore the microbiota composition and understand its dynamics and evolution during cheese manufacturing and ripening. Application of high-throughput DNA sequencing technologies have facilitated the more accurate identification of the cheese microbiome, detailed study of its potential functionality, and its contribution to the development of specific organoleptic properties. These technologies include amplicon sequencing, whole-metagenome shotgun sequencing, metatranscriptomics, and, most recently, metabolomics. In recent years, however, the application of multiple meta-omics approaches along with data integration analysis, which was enabled by advanced computational and bioinformatics tools, paved the way to better comprehension of the cheese ripening process, revealing significant associations between the cheese microbiota and metabolites, as well as their impact on cheese flavor and quality.
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Affiliation(s)
- Rania Anastasiou
- Laboratory of Dairy Research, Department of Food Science and Human Nutrition, Agricultural University of Athens, Iera Odos 75, 118 55 Athens, Greece; (M.K.); (M.G.); (A.A.); (G.Z.); (E.T.)
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Chang D, Islam ZU, Zheng J, Zhao J, Cui X, Yu Z. Inhibitor tolerance and bioethanol fermentability of levoglucosan-utilizing Escherichia coli were enhanced by overexpression of stress-responsive gene ycfR: The proteomics-guided metabolic engineering. Synth Syst Biotechnol 2021; 6:384-395. [PMID: 34853817 PMCID: PMC8605246 DOI: 10.1016/j.synbio.2021.11.003] [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: 06/21/2021] [Revised: 08/28/2021] [Accepted: 11/08/2021] [Indexed: 01/06/2023] Open
Abstract
Pretreatment of lignocellulosic biomass is crucial for the release of biofermentable sugars for biofuels production, which could greatly alleviate the burgeoning environment and energy crisis caused by the massive usage of traditional fossil fuels. Pyrolysis is a cost-saving pretreatment process that can readily decompose biomass into levoglucosan, a promising anhydrosugar; however, many undesired toxic compounds inhibitory to downstream microbial fermentation are also generated during the pyrolysis, immensely impeding the bioconversion of levoglucosan-containing pyrolysate. Here, we took the first insight into the proteomic responses of a levoglucosan-utilizing and ethanol-producing Escherichia coli to three representative biomass-derived inhibitors, identifying large amounts of differentially expressed proteins (DEPs) that could guide the downstream metabolic engineering for the development of inhibitor-resistant strains. Fifteen up- and eight down-regulated DEPs were further identified as the biomarker stress-responsive proteins candidate for cellular tolerance to multiple inhibitors. Among these biomarker proteins, YcfR exhibiting the highest expression fold-change level was chosen as the target of overexpression to validate proteomics results and develop robust strains with enhanced inhibitor tolerance and fermentation performance. Finally, based on four plasmid-borne genes encoding the levoglucosan kinase, pyruvate decarboxylase, alcohol dehydrogenase, and protein YcfR, a new recombinant strain E. coli LGE-ycfR was successfully created, showing much higher acetic acid-, furfural-, and phenol-tolerance levels compared to the control without overexpression of ycfR. The specific growth rate, final cell density, ethanol concentration, ethanol productivity, and levoglucosan consumption rate of the recombinant were also remarkably improved. From the proteomics-guided metabolic engineering and phenotypic observations, we for the first time corroborated that YcfR is a stress-induced protein responsive to multiple biomass-derived inhibitors, and also developed an inhibitors-resistant strain that could produce bioethanol from levoglucosan in the presence of inhibitors of relatively high concentration. The newly developed E. coli LGE-ycfR strain that could eliminate the commonly-used costly detoxicification processes, is of great potential for the in situ cost-effective bioethanol production from the biomass-derived pyrolytic substrates.
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Affiliation(s)
- Dongdong Chang
- College of Resources and Environment, University of Chinese Academy of Sciences, Beijing, 100049, PR China
| | - Zia Ul Islam
- College of Resources and Environment, University of Chinese Academy of Sciences, Beijing, 100049, PR China
- Department of Chemistry, Mississippi State University, Mississippi State, MS 39762, USA
| | - Junfang Zheng
- Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Capital Medical University, Beijing, 100069, PR China
| | - Jie Zhao
- College of Resources and Environment, University of Chinese Academy of Sciences, Beijing, 100049, PR China
| | - Xiaoyong Cui
- Yanshan Earth Critical Zone and Surface Fluxes Research Station, Chinese Academy of Sciences, No. 380 Huaibei Town, Huairou District, Beijing, 101408, PR China
| | - Zhisheng Yu
- College of Resources and Environment, University of Chinese Academy of Sciences, Beijing, 100049, PR China
- RCEES-IMCAS-UCAS Joint-Lab of Microbial Technology for Environmental Science, Beijing, 100085, PR China
- Corresponding author. College of Resources and Environment, University of Chinese Academy of Sciences, Beijing, 100049, PR China.
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Butanol is cytotoxic to Lactococcus lactis while ethanol and hexanol are cytostatic. Microbiology (Reading) 2017; 163:453-461. [DOI: 10.1099/mic.0.000441] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
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Raftari M, Ghafourian S, Abu Bakar F. Simultaneous lactic acidification and coagulation by using recombinant Lactococcus lactis strain. J Appl Microbiol 2016; 122:1009-1019. [PMID: 28028882 DOI: 10.1111/jam.13388] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2015] [Revised: 11/16/2016] [Accepted: 12/10/2016] [Indexed: 11/30/2022]
Abstract
AIMS This study was an attempt to create a novel milk clotting procedure using a recombinant bacterium capable of milk coagulation. METHODS AND RESULTS The Rhizomucor pusillus proteinase (RPP) gene was sub-cloned into a pALF expression vector. The recombinant pALF-RPP vector was then electro-transferred into Lactococcus lactis. Finally, the milk coagulation ability of recombinant L. lactis carrying a RPP gene was evaluated. Nucleotide sequencing of DNA insertion from the clone revealed that the RPP activity corresponded to an open reading frame consisting of 1218 bp coding for a 43·45 kDa RPP protein. The RPP protein assay results indicated that the highest RPP enzyme expression with 870 Soxhlet units (SU) per ml and 7914 SU/OD were obtained for cultures which were incubated at pH 5·5 and 30°C. Interestingly, milk coagulation was observed after 205 min of inoculating milk with recombinant L. lactis carrying the RPP gene. CONCLUSION The recombinant L. lactis carrying RPP gene has the ability to function as a starter culture for acidifying and subsequently coagulating milk by producing RPP as a milk coagulant agent. SIGNIFICANCE AND IMPACT OF THE STUDY Creating a recombinant starter culture bacterium that is able to coagulate milk. It is significant because the recombinant L. lactis has the ability to work as a starter culture and milk coagulation agent.
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Affiliation(s)
- M Raftari
- Faculty of Food Science and Technology, Universiti Putra Malaysia, Serdang, Selangor, Malaysia
| | - S Ghafourian
- Clinical Microbiology Research Center, Ilam University of Medical Sciences, Ilam, Iran.,Faculty of Medicine and Health Sciences, Universiti Putra Malaysia, Serdang, Selangor, Malaysia
| | - F Abu Bakar
- Faculty of Food Science and Technology, Universiti Putra Malaysia, Serdang, Selangor, Malaysia
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Araque I, Gil J, Carreté R, Constantí M, Bordons A, Reguant C. Arginine deiminase pathway genes and arginine degradation variability in Oenococcus oeni strains. Folia Microbiol (Praha) 2015; 61:109-18. [PMID: 26873388 DOI: 10.1007/s12223-015-0416-9] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2015] [Accepted: 07/10/2015] [Indexed: 01/03/2023]
Abstract
Trace amounts of the carcinogenic ethyl carbamate can appear in wine as a result of a reaction between ethanol and citrulline, which is produced from arginine degradation by some bacteria used in winemaking. In this study, arginine deiminase (ADI) pathway genes were evaluated in 44 Oenococcus oeni strains from wines originating from several locations in order to establish the relationship between the ability of a strain to degrade arginine and the presence of related genes. To detect the presence of arc genes of the ADI pathway in O. oeni, pairs of primers were designed to amplify arcA, arcB, arcC and arcD1 sequences. All strains contained these four genes. The same primers were used to confirm the organization of these genes in an arcABCD1 operon. Nevertheless, considerable variability in the ability to degrade arginine among these O. oeni strains was observed. Therefore, despite the presence of the arc genes in all strains, the expression patterns of individual genes must be strain dependent and influenced by the different wine conditions. Additionally, the presence of arc genes was also determined in the 57 sequenced strains of O. oeni available in GenBank, and the complete operon was found in 83% of strains derived from wine. The other strains were found to lack the arcB, arcC and arcD genes, but all contained sequences homologous to arcA, and some of them had also ADI activity.
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Affiliation(s)
- Isabel Araque
- Departament de Bioquímica i Biotecnologia, Facultat d'Enologia, Universitat Rovira i Virgili, Tarragona, Catalonia, Spain
| | - Joana Gil
- Departament de Bioquímica i Biotecnologia, Facultat d'Enologia, Universitat Rovira i Virgili, Tarragona, Catalonia, Spain
| | - Ramon Carreté
- Departament de Bioquímica i Biotecnologia, Facultat d'Enologia, Universitat Rovira i Virgili, Tarragona, Catalonia, Spain
| | - Magda Constantí
- Departament d'Enginyeria Química, ETSEQ, Universitat Rovira i Virgili, Tarragona, Catalonia, Spain
| | - Albert Bordons
- Departament de Bioquímica i Biotecnologia, Facultat d'Enologia, Universitat Rovira i Virgili, Tarragona, Catalonia, Spain.
| | - Cristina Reguant
- Departament de Bioquímica i Biotecnologia, Facultat d'Enologia, Universitat Rovira i Virgili, Tarragona, Catalonia, Spain
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Kelleher P, Murphy J, Mahony J, van Sinderen D. Next-generation sequencing as an approach to dairy starter selection. DAIRY SCIENCE & TECHNOLOGY 2015; 95:545-568. [PMID: 26798445 PMCID: PMC4712225 DOI: 10.1007/s13594-015-0227-4] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 01/26/2015] [Revised: 03/25/2015] [Accepted: 04/02/2015] [Indexed: 02/06/2023]
Abstract
Lactococcal and streptococcal starter strains are crucial ingredients to manufacture fermented dairy products. As commercial starter culture suppliers and dairy producers attempt to overcome issues of phage sensitivity and develop new product ranges, there is an ever increasing need to improve technologies for the rational selection of novel starter culture blends. Whole genome sequencing, spurred on by recent advances in next-generation sequencing platforms, is a promising approach to facilitate rapid identification and selection of such strains based on gene-trait matching. This review provides a comprehensive overview of the available methodologies to analyse the technological potential of candidate starter strains and highlights recent advances in the area of dairy starter genomics.
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Affiliation(s)
- Philip Kelleher
- School of Microbiology, University College Cork, Cork, Ireland
| | - James Murphy
- School of Microbiology, University College Cork, Cork, Ireland
| | - Jennifer Mahony
- School of Microbiology, University College Cork, Cork, Ireland
| | - Douwe van Sinderen
- School of Microbiology, University College Cork, Cork, Ireland
- Alimentary Pharmabiotic Centre, Biosciences Institute, University College Cork, Cork, Ireland
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Afiati F, - Y, R.A. Maheswari R. PEMANFAATAN BAKTERI PROBIOTIK INDIGENUS DALAM PEMBUATAN KEJU LUNAK. JURNAL TEKNOLOGI DAN INDUSTRI PANGAN 2014. [DOI: 10.6066/jtip.2014.25.1.7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
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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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Khemariya P, Singh S, Nath G, Gulati AK. Subspecies-Specific Nested PCR Assay for Detection ofLactococcus lactisspp.lactisand spp.cremoris. FOOD BIOTECHNOL 2013. [DOI: 10.1080/08905436.2013.811085] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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de Jong A, Hansen ME, Kuipers OP, Kilstrup M, Kok J. The transcriptional and gene regulatory network of Lactococcus lactis MG1363 during growth in milk. PLoS One 2013; 8:e53085. [PMID: 23349698 PMCID: PMC3547956 DOI: 10.1371/journal.pone.0053085] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2012] [Accepted: 11/27/2012] [Indexed: 11/18/2022] Open
Abstract
In the present study we examine the changes in the expression of genes of Lactococcus lactis subspecies cremoris MG1363 during growth in milk. To reveal which specific classes of genes (pathways, operons, regulons, COGs) are important, we performed a transcriptome time series experiment. Global analysis of gene expression over time showed that L. lactis adapted quickly to the environmental changes. Using upstream sequences of genes with correlated gene expression profiles, we uncovered a substantial number of putative DNA binding motifs that may be relevant for L. lactis fermentative growth in milk. All available novel and literature-derived data were integrated into network reconstruction building blocks, which were used to reconstruct and visualize the L. lactis gene regulatory network. This network enables easy mining in the chrono-transcriptomics data. A freely available website at http://milkts.molgenrug.nl gives full access to all transcriptome data, to the reconstructed network and to the individual network building blocks.
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Affiliation(s)
- Anne de Jong
- Department of Molecular Genetics, University of Groningen, Groningen Biomolecular Sciences and Biotechnology Institute, Groningen, The Netherlands
| | - Morten E. Hansen
- Center for Systems Microbiology, Institute of Systems Biology, Technical University of Denmark, Lyngby, Denmark
| | - Oscar P. Kuipers
- Department of Molecular Genetics, University of Groningen, Groningen Biomolecular Sciences and Biotechnology Institute, Groningen, The Netherlands
| | - Mogens Kilstrup
- Center for Systems Microbiology, Institute of Systems Biology, Technical University of Denmark, Lyngby, Denmark
| | - Jan Kok
- Department of Molecular Genetics, University of Groningen, Groningen Biomolecular Sciences and Biotechnology Institute, Groningen, The Netherlands
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Petrova P, Petrov K, Stoyancheva G. Starch-modifying enzymes of lactic acid bacteria - structures, properties, and applications. STARCH-STARKE 2012. [DOI: 10.1002/star.201200192] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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Gu X, Li C, Cai Y, Dong H, Xu W, Tian H, Yang J. Construction of Lactococcus lactis thyA-null using the Red recombination system. ANN MICROBIOL 2012. [DOI: 10.1007/s13213-012-0548-y] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
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van de Guchte M, Chaze T, Jan G, Mistou MY. Properties of probiotic bacteria explored by proteomic approaches. Curr Opin Microbiol 2012; 15:381-9. [PMID: 22658701 DOI: 10.1016/j.mib.2012.04.003] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/29/2012] [Revised: 03/09/2012] [Accepted: 04/05/2012] [Indexed: 02/07/2023]
Abstract
The study of health-beneficial effects that probiotic bacteria can exert on humans and animals is at its beginning. Pending scientific questions include the identification of molecular markers of the health-promoting activity of specific strains, which may be used to select novel probiotic strains and to gain understanding of the mechanisms underlying their effects. In that perspective, the role of bacterial proteins must be evaluated, placing proteomics-based approaches at the core of the field. Until now, most proteomic analyses focused on the dynamics of abundant cytoplasmic proteins during adaptation of bacteria to conditions mimicking the gastro-intestinal tract environment. The development of in silico and experimental procedures allowing identification and quantification of surface-exposed and secreted proteins should boost our understanding of bacteria-host crosstalk.
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Sequencing and transcriptional analysis of the biosynthesis gene cluster of putrescine-producing Lactococcus lactis. Appl Environ Microbiol 2011; 77:6409-18. [PMID: 21803900 DOI: 10.1128/aem.05507-11] [Citation(s) in RCA: 62] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Lactococcus lactis is a prokaryotic microorganism with great importance as a culture starter and has become the model species among the lactic acid bacteria. The long and safe history of use of L. lactis in dairy fermentations has resulted in the classification of this species as GRAS (General Regarded As Safe) or QPS (Qualified Presumption of Safety). However, our group has identified several strains of L. lactis subsp. lactis and L. lactis subsp. cremoris that are able to produce putrescine from agmatine via the agmatine deiminase (AGDI) pathway. Putrescine is a biogenic amine that confers undesirable flavor characteristics and may even have toxic effects. The AGDI cluster of L. lactis is composed of a putative regulatory gene, aguR, followed by the genes (aguB, aguD, aguA, and aguC) encoding the catabolic enzymes. These genes are transcribed as an operon that is induced in the presence of agmatine. In some strains, an insertion (IS) element interrupts the transcription of the cluster, which results in a non-putrescine-producing phenotype. Based on this knowledge, a PCR-based test was developed in order to differentiate nonproducing L. lactis strains from those with a functional AGDI cluster. The analysis of the AGDI cluster and their flanking regions revealed that the capacity to produce putrescine via the AGDI pathway could be a specific characteristic that was lost during the adaptation to the milk environment by a process of reductive genome evolution.
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Ndoye B, Lessard MH, LaPointe G, Roy D. Exploring suppression subtractive hybridization (SSH) for discriminating Lactococcus lactis ssp. cremoris SK11 and ATCC 19257 in mixed culture based on the expression of strain-specific genes. J Appl Microbiol 2010; 110:499-512. [DOI: 10.1111/j.1365-2672.2010.04902.x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
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Metatranscriptome analysis for insight into whole-ecosystem gene expression during spontaneous wheat and spelt sourdough fermentations. Appl Environ Microbiol 2010; 77:618-26. [PMID: 21097589 DOI: 10.1128/aem.02028-10] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Lactic acid bacteria (LAB) are of industrial importance in the production of fermented foods, including sourdough-derived products. Despite their limited metabolic capacity, LAB contribute considerably to important characteristics of fermented foods, such as extended shelf-life, microbial safety, improved texture, and enhanced organoleptic properties. Triggered by the considerable amount of LAB genomic information that became available during the last decade, transcriptome and, by extension, metatranscriptome studies have become one of the most appropriate research approaches to study whole-ecosystem gene expression in more detail. In this study, microarray analyses were performed using RNA sampled during four 10-day spontaneous sourdough fermentations carried out in the laboratory with an in-house-developed LAB functional gene microarray. For data analysis, a new algorithm was developed to calculate a net expression profile for each of the represented genes, allowing use of the microarray analysis beyond the species level. In addition, metabolite target analyses were performed on the sourdough samples to relate gene expression with metabolite production. The results revealed the activation of different key metabolic pathways, the ability to use carbohydrates other than glucose (e.g., starch and maltose), and the conversion of amino acids as a contribution to redox equilibrium and flavor compound generation in LAB during sourdough fermentation.
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Genome sequences of Lactococcus lactis MG1363 (revised) and NZ9000 and comparative physiological studies. J Bacteriol 2010; 192:5806-12. [PMID: 20639323 DOI: 10.1128/jb.00533-10] [Citation(s) in RCA: 93] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Lactococcus lactis NZ9000 and its parent MG1363 are the most commonly used lactic acid bacteria for expression and physiological studies. We noted unexpected but significant differences in the growth behaviors of both strains. We sequenced the entire genomes of the original NZ9000 and MG1363 strains using an ultradeep sequencing strategy. The analysis of the L. lactis NZ9000 genome yielded 79 differences, mostly point mutations, with the annotated genome sequence of L. lactis MG1363. Resequencing of the MG1363 strain revealed that 73 out of the 79 differences were due to errors in the published sequence. Comparative transcriptomic studies revealed several differences in the regulation of genes involved in sugar fermentation, which can be explained by two specific mutations in a region of the ptcC promoter with a key role in the regulation of cellobiose and glucose uptake.
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MILLS SUSAN, O’SULLIVAN ORLA, HILL COLIN, FITZGERALD GERALD, ROSS RPAUL. The changing face of dairy starter culture research: From genomics to economics. INT J DAIRY TECHNOL 2010. [DOI: 10.1111/j.1471-0307.2010.00563.x] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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22
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Prasad SB, Jayaraman G, Ramachandran KB. Hyaluronic acid production is enhanced by the additional co-expression of UDP-glucose pyrophosphorylase in Lactococcus lactis. Appl Microbiol Biotechnol 2009; 86:273-83. [DOI: 10.1007/s00253-009-2293-0] [Citation(s) in RCA: 67] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2009] [Revised: 10/01/2009] [Accepted: 10/03/2009] [Indexed: 11/29/2022]
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23
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Margolles A, Moreno JA, Ruiz L, Marelli B, Magni C, de Los Reyes-Gavilán CG, Ruas-Madiedo P. Production of human growth hormone by Lactococcus lactis. J Biosci Bioeng 2009; 109:322-4. [PMID: 20226370 DOI: 10.1016/j.jbiosc.2009.10.006] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2009] [Accepted: 10/06/2009] [Indexed: 11/16/2022]
Abstract
A synthetic gene coding for human growth hormone was expressed in Lactococcus lactis. The presence of the recombinant protein was assayed and quantified using ELISA tests. Human growth hormone was detected at high concentrations and displayed a biological activity similar to the one shown by commercial human growth hormone.
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Affiliation(s)
- Abelardo Margolles
- Departamento de Microbiología y Bioquímica de Productos Lácteos, Instituto de Productos Lácteos de Asturias (CSIC), Carretera de Infiesto s/n 3300 Villaviciosa, Asturias, Spain.
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Araque I, Gil J, Carreté R, Bordons A, Reguant C. Detection of arc genes related with the ethyl carbamate precursors in wine lactic acid bacteria. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2009; 57:1841-1847. [PMID: 19219988 DOI: 10.1021/jf803421w] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
Trace amounts of the carcinogen ethyl carbamate can appear in wine by the reaction of ethanol with compounds such as citrulline and carbamyl phosphate, which are produced from arginine degradation by some wine lactic acid bacteria (LAB). In this work, the presence of arc genes for the arginine-deiminase pathway was studied in several strains of different species of LAB. Their ability to degrade arginine was also studied. To detect the presence of arc genes, degenerate primers were designed from the alignment of protein sequences in already sequenced LAB. The usefulness of these degenerate primers has been proven by sequencing some of the amplified PCR fragments and searching for homologies with published sequences of the same species and related ones. Correlation was found between the presence of genes and the ability to degrade arginine. Degrading strains included all heterofermentative lactobacilli, Oenococcus oeni , Pediococcus pentosaceus , and some strains of Leuconostoc mesenteroides and Lactobacillus plantarum .
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Affiliation(s)
- Isabel Araque
- Departament de Bioquimica i Biotecnologia, Facultat d'Enologia, Campus Sescelades, Universitat Rovira i Virgili, Tarragona, Catalonia, Spain
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Affiliation(s)
- Roland J Siezen
- Kluyver Centre for Genomics of Industrial Fermentation, TI Food and Nutrition, Wageningen, The Netherlands.
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26
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De Vuyst L, Tsakalidou E. Streptococcus macedonicus, a multi-functional and promising species for dairy fermentations. Int Dairy J 2008. [DOI: 10.1016/j.idairyj.2007.10.006] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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27
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Genome-scale genotype-phenotype matching of two Lactococcus lactis isolates from plants identifies mechanisms of adaptation to the plant niche. Appl Environ Microbiol 2007; 74:424-36. [PMID: 18039825 DOI: 10.1128/aem.01850-07] [Citation(s) in RCA: 90] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Lactococcus lactis is a primary constituent of many starter cultures used for the manufacturing of fermented dairy products, but the species also occurs in various nondairy niches such as (fermented) plant material. Three genome sequences of L. lactis dairy strains (IL-1403, SK11, and MG1363) are publicly available. An extensive molecular and phenotypic diversity analysis was now performed on two L. lactis plant isolates. Diagnostic sequencing of their genomes resulted in over 2.5 Mb of sequence for each strain. A high synteny was found with the genome of L. lactis IL-1403, which was used as a template for contig mapping and locating deletions and insertions in the plant L. lactis genomes. Numerous genes were identified that do not have homologs in the published genome sequences of dairy L. lactis strains. Adaptation to growth on substrates derived from plant cell walls is evident from the presence of gene sets for the degradation of complex plant polymers such as xylan, arabinan, glucans, and fructans but also for the uptake and conversion of typical plant cell wall degradation products such as alpha-galactosides, beta-glucosides, arabinose, xylose, galacturonate, glucuronate, and gluconate. Further niche-specific differences are found in genes for defense (nisin biosynthesis), stress response (nonribosomal peptide synthesis and various transporters), and exopolysaccharide biosynthesis, as well as the expected differences in various mobile elements such as prophages, plasmids, restriction-modification systems, and insertion sequence elements. Many of these genes were identified for the first time in Lactococcus lactis. In most cases good correspondence was found with the phenotypic characteristics of these two strains.
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van Hylckama Vlieg J, Hugenholtz J. Mining natural diversity of lactic acid bacteria for flavour and health benefits. Int Dairy J 2007. [DOI: 10.1016/j.idairyj.2007.02.010] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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29
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Rademaker JLW, Herbet H, Starrenburg MJC, Naser SM, Gevers D, Kelly WJ, Hugenholtz J, Swings J, van Hylckama Vlieg JET. Diversity analysis of dairy and nondairy Lactococcus lactis isolates, using a novel multilocus sequence analysis scheme and (GTG)5-PCR fingerprinting. Appl Environ Microbiol 2007; 73:7128-37. [PMID: 17890345 PMCID: PMC2168189 DOI: 10.1128/aem.01017-07] [Citation(s) in RCA: 84] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The diversity of a collection of 102 lactococcus isolates including 91 Lactococcus lactis isolates of dairy and nondairy origin was explored using partial small subunit rRNA gene sequence analysis and limited phenotypic analyses. A subset of 89 strains of L. lactis subsp. cremoris and L. lactis subsp. lactis isolates was further analyzed by (GTG)(5)-PCR fingerprinting and a novel multilocus sequence analysis (MLSA) scheme. Two major genomic lineages within L. lactis were found. The L. lactis subsp. cremoris type-strain-like genotype lineage included both L. lactis subsp. cremoris and L. lactis subsp. lactis isolates. The other major lineage, with a L. lactis subsp. lactis type-strain-like genotype, comprised L. lactis subsp. lactis isolates only. A novel third genomic lineage represented two L. lactis subsp. lactis isolates of nondairy origin. The genomic lineages deviate from the subspecific classification of L. lactis that is based on a few phenotypic traits only. MLSA of six partial genes (atpA, encoding ATP synthase alpha subunit; pheS, encoding phenylalanine tRNA synthetase; rpoA, encoding RNA polymerase alpha chain; bcaT, encoding branched chain amino acid aminotransferase; pepN, encoding aminopeptidase N; and pepX, encoding X-prolyl dipeptidyl peptidase) revealed 363 polymorphic sites (total length, 1,970 bases) among 89 L. lactis subsp. cremoris and L. lactis subsp. lactis isolates with unique sequence types for most isolates. This allowed high-resolution cluster analysis in which dairy isolates form subclusters of limited diversity within the genomic lineages. The pheS DNA sequence analysis yielded two genetic groups dissimilar to the other genotyping analysis-based lineages, indicating a disparate acquisition route for this gene.
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Abstract
The increasing number of genomic and post-genomic studies on Gram-positive organisms and especially on lactic acid bacteria brings a lot of information on sugar catabolism in these bacteria. Like for many other bacteria, glucose is the most preferred source of carbon and energy for Lactococcus lactis. Other carbon sources can induce their own utilization in the absence of well-metabolized sugar. These processes engage numbers of genes and undergo complex mechanisms of regulation. In this review, we discuss various biochemical and genetic control mechanisms involved in sugar catabolism, like regulation by repressors, activators, antiterminators or carbon catabolite repression control.
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Affiliation(s)
- Magdalena Kowalczyk
- Department of Microbial Biochemistry, Institute of Biochemistry and Biophysics PAS, Pawinskiego, Warszawa, Poland.
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31
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Gálvez A, Abriouel H, López RL, Ben Omar N. Bacteriocin-based strategies for food biopreservation. Int J Food Microbiol 2007; 120:51-70. [PMID: 17614151 DOI: 10.1016/j.ijfoodmicro.2007.06.001] [Citation(s) in RCA: 617] [Impact Index Per Article: 36.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2006] [Revised: 12/21/2006] [Indexed: 11/15/2022]
Abstract
Bacteriocins are ribosomally-synthesized peptides or proteins with antimicrobial activity, produced by different groups of bacteria. Many lactic acid bacteria (LAB) produce bacteriocins with rather broad spectra of inhibition. Several LAB bacteriocins offer potential applications in food preservation, and the use of bacteriocins in the food industry can help to reduce the addition of chemical preservatives as well as the intensity of heat treatments, resulting in foods which are more naturally preserved and richer in organoleptic and nutritional properties. This can be an alternative to satisfy the increasing consumers demands for safe, fresh-tasting, ready-to-eat, minimally-processed foods and also to develop "novel" food products (e.g. less acidic, or with a lower salt content). In addition to the available commercial preparations of nisin and pediocin PA-1/AcH, other bacteriocins (like for example lacticin 3147, enterocin AS-48 or variacin) also offer promising perspectives. Broad-spectrum bacteriocins present potential wider uses, while narrow-spectrum bacteriocins can be used more specifically to selectively inhibit certain high-risk bacteria in foods like Listeria monocytogenes without affecting harmless microbiota. Bacteriocins can be added to foods in the form of concentrated preparations as food preservatives, shelf-life extenders, additives or ingredients, or they can be produced in situ by bacteriocinogenic starters, adjunct or protective cultures. Immobilized bacteriocins can also find application for development of bioactive food packaging. In recent years, application of bacteriocins as part of hurdle technology has gained great attention. Several bacteriocins show additive or synergistic effects when used in combination with other antimicrobial agents, including chemical preservatives, natural phenolic compounds, as well as other antimicrobial proteins. This, as well as the combined use of different bacteriocins may also be an attractive approach to avoid development of resistant strains. The combination of bacteriocins and physical treatments like high pressure processing or pulsed electric fields also offer good opportunities for more effective preservation of foods, providing an additional barrier to more refractile forms like bacterial endospores as well. The effectiveness of bacteriocins is often dictated by environmental factors like pH, temperature, food composition and structure, as well as the food microbiota. Foods must be considered as complex ecosystems in which microbial interactions may have a great influence on the microbial balance and proliferation of beneficial or harmful bacteria. Recent developments in molecular microbial ecology can help to better understand the global effects of bacteriocins in food ecosystems, and the study of bacterial genomes may reveal new sources of bacteriocins.
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Affiliation(s)
- Antonio Gálvez
- Area de Microbiología, Facultad de Ciencias Experimentales, Universidad de Jaén, Spain.
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32
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Margolles A, Flórez AB, Moreno JA, van Sinderen D, de Los Reyes-Gavilán CG. Two membrane proteins from Bifidobacterium breve UCC2003 constitute an ABC-type multidrug transporter. MICROBIOLOGY-SGM 2007; 152:3497-3505. [PMID: 17159201 DOI: 10.1099/mic.0.29097-0] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Intrinsic resistance to drugs is one of the main determining factors in bacterial survival in the intestinal ecosystem. This is mediated by, among others, multidrug resistance (MDR) transporters, membrane proteins which extrude noxious compounds with very different chemical structures and cellular targets. Two genes from Bifidobacterium breve encoding hypothetical membrane proteins with a high homology with members of the ATP-binding cassette (ABC) family of multidrug efflux transporters, were expressed separately and jointly in Lactococcus lactis. Cells co-expressing both proteins exhibited enhanced resistance levels to the antimicrobials nisin and polymyxin B. Furthermore, the drug extrusion activity in membrane vesicles was increased when both proteins were co-expressed, compared to membranes in which the proteins were produced independently. Both proteins were co-purified from the membrane as a stable complex in a 1:1 ratio. This is believed to be the first study of a functional ABC-type multidrug transporter in Bifidobacterium and contributes to our understanding of the molecular mechanisms underlying the capacity of intestinal bacteria to tolerate cytotoxic compounds.
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Affiliation(s)
- Abelardo Margolles
- Instituto de Productos Lácteos de Asturias, Consejo Superior de Investigaciones Científicas (CSIC), Ctra Infiesto s/n, 33300, Villaviciosa, Asturias, Spain
| | - Ana Belén Flórez
- Instituto de Productos Lácteos de Asturias, Consejo Superior de Investigaciones Científicas (CSIC), Ctra Infiesto s/n, 33300, Villaviciosa, Asturias, Spain
| | - José Antonio Moreno
- Department of Microbiology and Alimentary Pharmabiotic Centre, University College Cork, Western Road, Cork, Ireland
- Instituto de Productos Lácteos de Asturias, Consejo Superior de Investigaciones Científicas (CSIC), Ctra Infiesto s/n, 33300, Villaviciosa, Asturias, Spain
| | - Douwe van Sinderen
- Department of Microbiology and Alimentary Pharmabiotic Centre, University College Cork, Western Road, Cork, Ireland
| | - Clara G de Los Reyes-Gavilán
- Instituto de Productos Lácteos de Asturias, Consejo Superior de Investigaciones Científicas (CSIC), Ctra Infiesto s/n, 33300, Villaviciosa, Asturias, Spain
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van Belkum A, Tassios PT, Dijkshoorn L, Haeggman S, Cookson B, Fry NK, Fussing V, Green J, Feil E, Gerner-Smidt P, Brisse S, Struelens M. Guidelines for the validation and application of typing methods for use in bacterial epidemiology. Clin Microbiol Infect 2007; 13 Suppl 3:1-46. [PMID: 17716294 DOI: 10.1111/j.1469-0691.2007.01786.x] [Citation(s) in RCA: 530] [Impact Index Per Article: 31.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
For bacterial typing to be useful, the development, validation and appropriate application of typing methods must follow unified criteria. Over a decade ago, ESGEM, the ESCMID (Europen Society for Clinical Microbiology and Infectious Diseases) Study Group on Epidemiological Markers, produced guidelines for optimal use and quality assessment of the then most frequently used typing procedures. We present here an update of these guidelines, taking into account the spectacular increase in the number and quality of typing methods made available over the past decade. Newer and older, phenotypic and genotypic methods for typing of all clinically relevant bacterial species are described according to their principles, advantages and disadvantages. Criteria for their evaluation and application and the interpretation of their results are proposed. Finally, the issues of reporting, standardisation, quality assessment and international networks are discussed. It must be emphasised that typing results can never stand alone and need to be interpreted in the context of all available epidemiological, clinical and demographical data relating to the infectious disease under investigation. A strategic effort on the part of all workers in the field is thus mandatory to combat emerging infectious diseases, as is financial support from national and international granting bodies and health authorities.
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Affiliation(s)
- A van Belkum
- Erasmus MC, Department of Medical Microbiology and Infectious Diseases, Rotterdam, The Netherlands.
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Behr J, Gänzle MG, Vogel RF. Characterization of a highly hop-resistant Lactobacillus brevis strain lacking hop transport. Appl Environ Microbiol 2006; 72:6483-92. [PMID: 17021196 PMCID: PMC1610305 DOI: 10.1128/aem.00668-06] [Citation(s) in RCA: 65] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Resistance to hops is a prerequisite for lactic acid bacteria to spoil beer. In this study we analyzed mechanisms of hop resistance of Lactobacillus brevis at the metabolism, membrane physiology, and cell wall composition levels. The beer-spoiling organism L. brevis TMW 1.465 was adapted to high concentrations of hop compounds and compared to a nonadapted strain. Upon adaptation to hops the metabolism changed to minimize ethanol stress. Fructose was used predominantly as a carbon source by the nonadapted strain but served as an electron acceptor upon adaptation to hops, with concomitant formation of acetate instead of ethanol. Furthermore, hop adaptation resulted in higher levels of lipoteichoic acids (LTA) incorporated into the cell wall and altered composition and fluidity of the cytoplasmic membrane. The putative transport protein HitA and enzymes of the arginine deiminase pathway were overexpressed upon hop adaptation. HorA was not expressed, and the transport of hop compounds from the membrane to the extracellular space did not account for increased resistance to hops upon adaptation. Accordingly, hop resistance is a multifactorial dynamic property, which can develop during adaptation. During hop adaptation, arginine catabolism contributes to energy and generation of the proton motive force until a small fraction of the population has established structural improvements. This acquired hop resistance is energy independent and involves an altered cell wall composition. LTA shields the organism from accompanying stresses and provides a reservoir of divalent cations, which are otherwise scarce as a result of their complexation by hop acids. Some of the mechanisms involved in hop resistance overlap with mechanisms of pH resistance and ethanol tolerance and as a result enable beer spoilage by L. brevis.
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Affiliation(s)
- Jürgen Behr
- Technische Mikrobiologie, Technische Universität München, Weihenstephaner Steig 16, 85350 Freising, Germany
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35
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Affiliation(s)
- Kira S Makarova
- National Center for Biotechnology Information, National Library of Medicine, National Institutes of Health, Bethesda, MD 20894, USA.
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36
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Houlihan AJ, Russell JB. The Effect of Calcium and Magnesium on the Activity of Bovicin HC5 and Nisin. Curr Microbiol 2006; 53:365-9. [PMID: 17036211 DOI: 10.1007/s00284-005-0417-z] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2005] [Accepted: 12/02/2005] [Indexed: 10/24/2022]
Abstract
Some Gram-positive bacteria produce small peptides (bacteriocins) that have antimicrobial activity, but many bacteria can become bacteriocin resistant. Bovicin HC5, a lantibiotic produced by Streptococcus bovis HC5, has the ability to inhibit nisin-resistant bacteria. Because nisin resistance has in many cases been correlated with an alteration of lipoteichoic acids or the polar head groups of membrane phospholipids, we decided to examine the effect of divalent cations on nisin and bovicin HC5 activity. Both bacteriocins catalyzed potassium efflux from S. bovis JB1, a non-bacteriocin-producing strain. The addition of large amounts (100 mM) of calcium or magnesium increased the ability of S. bovis JB1 to bind Congo red (an anionic dye) and counteracted bacteriocin-mediated potassium loss. Calcium was more effective than magnesium in decreasing nisin activity, but the reverse was observed with bovicin HC5. Nisin-resistant S. bovis JB1 cells bound three times as much Congo red as nisin-sensitive cells, and this result is consistent with the idea that changes in cell surface charge can be a mechanism of bacteriocin resistance. The nisin-resistant cells were less susceptible to bovicin HC5, but bovicin HC5 still caused a 50% depletion of intracellular potassium. These results indicate that nisin and bovicin HC5 react differently with the cell surfaces of Gram-positive bacteria.
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Affiliation(s)
- Adam J Houlihan
- Department of Microbiology, Cornell University, Ithaca, NY, 14853, USA
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37
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O'Driscoll J, Glynn F, Fitzgerald GF, van Sinderen D. Sequence analysis of the lactococcal plasmid pNP40: a mobile replicon for coping with environmental hazards. J Bacteriol 2006; 188:6629-39. [PMID: 16952955 PMCID: PMC1595478 DOI: 10.1128/jb.00672-06] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The conjugative lactococcal plasmid pNP40, identified in Lactococcus lactis subsp. diacetylactis DRC3, possesses a potent complement of bacteriophage resistance systems, which has stimulated its application as a fitness-improving, food-grade genetic element for industrial starter cultures. The complete sequence of this plasmid allowed the mapping of previously known functions including replication, conjugation, bacteriocin resistance, heavy metal tolerance, and bacteriophage resistance. In addition, functions for cold shock adaptation and DNA damage repair were identified, further confirming pNP40's contribution to environmental stress protection. A plasmid cointegration event appears to have been part of the evolution of pNP40, resulting in a "stockpiling" of bacteriophage resistance systems.
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Affiliation(s)
- Jonathan O'Driscoll
- Department of Microbiology, University College Cork, Western Road, Cork, Ireland
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38
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ten Cate JM. Biofilms, a new approach to the microbiology of dental plaque. Odontology 2006; 94:1-9. [PMID: 16998612 DOI: 10.1007/s10266-006-0063-3] [Citation(s) in RCA: 160] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2006] [Accepted: 05/23/2006] [Indexed: 12/20/2022]
Abstract
Dental plaque has the properties of a biofilm, similar to other biofilms found in the body and the environment. Modern molecular biological techniques have identified about 1000 different bacterial species in the dental biofilm, twice as many as can be cultured. Oral biofilms are very heterogeneous in structure. Dense mushroom-like structures originate from the enamel surface, interspersed with bacteria-free channels used as diffusion pathways. The channels are probably filled with an extracellular polysaccharide (EPS) matrix produced by the bacteria. Bacteria in biofilms communicate through signaling molecules, and use this "quorum-sensing" system to optimize their virulence factors and survival. Bacteria in a biofilm have a physiology different from that of planktonic cells. They generally live under nutrient limitation and often in a dormant state. Such "sleepy" bacteria respond differently to antibiotics and antimicrobials, because these agents were generally selected in experiments with metabolically active bacteria. This is one of the explanations as to why antibiotics and antimicrobials are not as successful in the clinic as could be expected from laboratory studies. In addition, it has been found that many therapeutic agents bind to the biofilm EPS matrix before they even reach the bacteria, and are thereby inactivated. Taken together, these fundings highlight why the study of bacteria in the oral cavity is now taken on by studying the biofilms rather than individual species.
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Affiliation(s)
- Jacob M ten Cate
- Department of Cariology Endodontolgy Pedodontology, Academic Centre for Dentistry ACTA, Louwesweg 1, 1066 EA Amsterdam, The Netherlands.
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39
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Hilmi HTA, Kylä-Nikkilä K, Ra R, Saris PEJ. Nisin induction without nisin secretion. Microbiology (Reading) 2006; 152:1489-1496. [PMID: 16622065 DOI: 10.1099/mic.0.28544-0] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Nisin Z, a post-translationally modified antimicrobial peptide ofLactococcus lactis, is positively autoregulated by extracellular nisin via the two-component regulatory proteins NisRK. A mutation in the nisin NisT transporter renderedL. lactisincapable of nisin secretion, and nisin accumulated inside the cells. Normally nisin is activated after secretion by the serine protease NisP in the cell wall. This study showed that when secretion of nisin was blocked, intracellular proteolytic activity could cleave the N-terminal leader peptide of nisin precursor, resulting in active nisin. The isolated cytoplasm of a non-nisin producer could also cleave the leader from the nisin precursor, showing that the cytoplasm ofL. lactiscells does contain proteolytic activity capable of cleaving the leader from fully modified nisin precursor. Nisin could not be detected in the growth supernatant of the NisT mutant strain with a nisin-sensing strain (sensitivity 10 pg ml−1), which has a green fluorescent protein gene connected to the nisin-induciblenisApromoter and a functional nisin signal transduction circuit. Northern analysis of the NisT mutant cells revealed that even though the cells could not secrete nisin, the nisin-inducible promoter PnisZwas active. In anisBornisCbackground, where nisin could not be fully modified due to the mutations in the nisin modification machinery, the unmodified or partly modified nisin precursor accumulated in the cytoplasm. This immature nisin could not induce the PnisZpromoter. The results suggest that when active nisin is accumulated in the cytoplasm, it can insert into the membrane and from there extrude parts of the molecule into the pseudoperiplasmic space to interact with the signal-recognition domain of the histidine kinase NisK. Potentially, signal presentation via the membrane represents a general pathway for amphiphilic signals to interact with their sensors for signal transduction.
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Affiliation(s)
- Hanan T Abbas Hilmi
- Department of Applied Chemistry and Microbiology, PO Box 56, FI-00014 University of Helsinki, Finland
| | - Kari Kylä-Nikkilä
- Department of Applied Chemistry and Microbiology, PO Box 56, FI-00014 University of Helsinki, Finland
| | - Runar Ra
- Department of Applied Chemistry and Microbiology, PO Box 56, FI-00014 University of Helsinki, Finland
| | - Per E J Saris
- Department of Applied Chemistry and Microbiology, PO Box 56, FI-00014 University of Helsinki, Finland
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van Hylckama Vlieg JET, Rademaker JLW, Bachmann H, Molenaar D, Kelly WJ, Siezen RJ. Natural diversity and adaptive responses of Lactococcus lactis. Curr Opin Biotechnol 2006; 17:183-90. [PMID: 16517150 DOI: 10.1016/j.copbio.2006.02.007] [Citation(s) in RCA: 66] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2006] [Revised: 01/31/2006] [Accepted: 02/20/2006] [Indexed: 10/24/2022]
Abstract
Lactococcus lactis is the primary model organism for lactic acid bacteria (LAB) and is widely used in the production of fermented dairy products. In recent years there has been increasing interest in strains isolated from non-dairy environments, as these exhibit a high metabolic diversity and have unique flavour-forming activities. Recent progress has been made in understanding the natural diversity and adaptive responses of L. lactis from dairy and non-dairy origins. Genome sequencing and comparative genomics have also had an impact on understanding natural diversity within the species, and have provided new opportunities for industrial strain development.
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Affiliation(s)
- Johan E T van Hylckama Vlieg
- NIZO Food Research, Kluyver Centre for Genomics of Industrial Fermentation, PO Box 20, 6710 BA Ede, The Netherlands.
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