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Freed E, Fenster J, Smolinski SL, Walker J, Henard CA, Gill R, Eckert CA. Building a genome engineering toolbox in nonmodel prokaryotic microbes. Biotechnol Bioeng 2018; 115:2120-2138. [PMID: 29750332 DOI: 10.1002/bit.26727] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2017] [Revised: 04/02/2018] [Accepted: 03/10/2018] [Indexed: 12/26/2022]
Abstract
The realization of a sustainable bioeconomy requires our ability to understand and engineer complex design principles for the development of platform organisms capable of efficient conversion of cheap and sustainable feedstocks (e.g., sunlight, CO2 , and nonfood biomass) into biofuels and bioproducts at sufficient titers and costs. For model microbes, such as Escherichia coli, advances in DNA reading and writing technologies are driving the adoption of new paradigms for engineering biological systems. Unfortunately, microbes with properties of interest for the utilization of cheap and renewable feedstocks, such as photosynthesis, autotrophic growth, and cellulose degradation, have very few, if any, genetic tools for metabolic engineering. Therefore, it is important to develop "design rules" for building a genetic toolbox for novel microbes. Here, we present an overview of our current understanding of these rules for the genetic manipulation of prokaryotic microbes and the available genetic tools to expand our ability to genetically engineer nonmodel systems.
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Affiliation(s)
- Emily Freed
- National Renewable Energy Laboratory, Biosciences Center, Golden, CO.,Renewable and Sustainable Energy Institute, University of Colorado, Boulder, CO
| | - Jacob Fenster
- Renewable and Sustainable Energy Institute, University of Colorado, Boulder, CO.,Chemical and Biological Engineering, University of Colorado, Boulder, CO
| | | | - Julie Walker
- Renewable and Sustainable Energy Institute, University of Colorado, Boulder, CO
| | - Calvin A Henard
- National Renewable Energy Laboratory, National Bioenergy Center, Golden, CO
| | - Ryan Gill
- National Renewable Energy Laboratory, Biosciences Center, Golden, CO.,Renewable and Sustainable Energy Institute, University of Colorado, Boulder, CO.,Chemical and Biological Engineering, University of Colorado, Boulder, CO
| | - Carrie A Eckert
- National Renewable Energy Laboratory, Biosciences Center, Golden, CO.,Renewable and Sustainable Energy Institute, University of Colorado, Boulder, CO
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2
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Landete JM, Medina M, Arqués JL. Fluorescent reporter systems for tracking probiotic lactic acid bacteria and bifidobacteria. World J Microbiol Biotechnol 2016; 32:119. [PMID: 27263014 DOI: 10.1007/s11274-016-2077-5] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2016] [Accepted: 04/27/2016] [Indexed: 12/19/2022]
Abstract
In the last two decades, there has been increasing evidence supporting the role of the intestinal microbiota in health and disease, as well as the use of probiotics to modulate its activity and composition. Probiotic bacteria selected for commercial use in foods, mostly lactic acid bacteria and bifidobacteria, must survive in sufficient numbers during the manufacturing process, storage, and passage through the gastro-intestinal tract. They have several modes of action and it is crucial to unravel the mechanisms underlying their postulated beneficial effects. To track their survival and persistence, and to analyse their interaction with the gastro-intestinal epithelia it is essential to discriminate probiotic strains from endogenous microbiota. Fluorescent reporter proteins are relevant tools that can be exploited as a non-invasive marker system for in vivo real-time imaging in complex ecosystems as well as in vitro fluorescence labelling. Oxygen is required for many of these reporter proteins to fluoresce, which is a major drawback in anoxic environments. However, some new fluorescent proteins are able to overcome the potential problems caused by oxygen limitations. The current available approaches and the benefits/disadvantages of using reporter vectors containing fluorescent proteins for labelling of bacterial probiotic species commonly used in food are addressed.
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Affiliation(s)
- José M Landete
- Dpto. de Tecnología de Alimentos, INIA, Carretera de La Coruña Km 7, 28040, Madrid, Spain
| | - Margarita Medina
- Dpto. de Tecnología de Alimentos, INIA, Carretera de La Coruña Km 7, 28040, Madrid, Spain
| | - Juan L Arqués
- Dpto. de Tecnología de Alimentos, INIA, Carretera de La Coruña Km 7, 28040, Madrid, Spain.
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3
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Shareck J, Choi Y, Lee B, Miguez CB. Cloning Vectors Based on Cryptic Plasmids Isolated from Lactic Acid Bacteria:Their Characteristics and Potential Applications in Biotechnology. Crit Rev Biotechnol 2010; 24:155-208. [PMID: 15707158 DOI: 10.1080/07388550490904288] [Citation(s) in RCA: 56] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
Lactic acid bacteria (LAB) are Gram positive bacteria, widely distributed in nature, and industrially important as they are used in a variety of industrial food fermentations. The use of genetic engineering techniques is an effective means of enhancing the industrial applicability of LAB. However, when using genetic engineering technology, safety becomes an essential factor for the application of improved LAB to the food industry. Cloning and expression systems should be derived preferably from LAB cryptic plasmids that generally encode genes for which functions can be proposed, but no phenotypes can be observed. However, some plasmid-encoded functions have been discovered in cryptic plasmids originating from Lactobacillus, Streptococcus thermophilus, and Pediococcus spp. and can be used as selective marker systems in vector construction. This article presents information concerning LAB cryptic plasmids, and their structures, functions, and applications. A total of 134 cryptic plasmids collated are discussed.
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Affiliation(s)
- Julie Shareck
- Department of Food Science and Agricultural Chemistry, McGill University, Ste-Anne-de-Bellevue, Quebec, Canada
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4
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Applegate T, Klose V, Steiner T, Ganner A, Schatzmayr G. Probiotics and phytogenics for poultry: Myth or reality? J APPL POULTRY RES 2010. [DOI: 10.3382/japr.2010-00168] [Citation(s) in RCA: 96] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
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5
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Labrie S, Bart C, Vadeboncoeur C, Moineau S. Use of an α-Galactosidase Gene as a Food-Grade Selection Marker for Streptococcus thermophilus. J Dairy Sci 2005; 88:2341-7. [PMID: 15956297 DOI: 10.3168/jds.s0022-0302(05)72912-x] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
The alpha-galactosidase gene (aga) of Lactococcus raffinolactis ATCC 43920 was previously shown to be an efficient food-grade selection marker in Lactococcus lactis and Pediococcus acidilactici but not in Streptococcus thermophilus. In this study, we demonstrated that the alpha-galactosidase of L. raffinolactis is thermolabile and inoperative at 42 degrees C, the optimal growth temperature of S. thermophilus. An in vitro assay indicated that the activity of this alpha-galactosidase at 42 degrees C was only 3% of that at 30 degrees C, whereas the enzyme retained 23% of its activity at 37 degrees C. Transformation of Strep. thermophilus RD733 with the shuttle-vector pNZ123 bearing the aga gene of L. raffinolactis (pRAF301) generated transformants that were stable and able to grow on melibiose and raffinose at 37 degrees C or below. The transformed cells possessed 6-fold more alpha-galactosidase activity after growth on melibiose than cells grown on lactose. Slot-blot analyses of aga mRNA indicated that repression by lactose occurred at the transcriptional level. The presence of pRAF301 did not interfere with the lactic acid production when the transformed cells of Strep. thermophilus were grown at the optimal temperature in milk. Using the recombinant plasmid pRAF301, which carries a chloramphenicol resistance gene in addition to aga, we showed that both markers were equally efficient at differentiating transformed from nontransformed cells. The aga gene of L. raffinolactis can be used as a highly efficient selection marker in Strep. thermophilus.
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Affiliation(s)
- S Labrie
- Département de Biochimie et de Microbiologie, Faculté des Sciences et de Génie, Groupe de Recherche en Ecologie Buccale, Université Laval, Quebec City, Québec, G1K 7P4, Canada
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6
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São-José C, Santos S, Nascimento J, Brito-Madurro AG, Parreira R, Santos MA. Diversity in the lysis-integration region of oenophage genomes and evidence for multiple tRNA loci, as targets for prophage integration in Oenococcus oeni. Virology 2004; 325:82-95. [PMID: 15231388 DOI: 10.1016/j.virol.2004.04.029] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2004] [Revised: 04/20/2004] [Accepted: 04/27/2004] [Indexed: 11/22/2022]
Abstract
The central genomic regions of Oenococcus oeni phages fOg30 and fOgPSU1 have been compared with the equivalent regions of oenophages fOg44 and phi 10MC. In all cases, an almost identical endolysin gene was followed by one of two orfs, encoding putative holins (orf117 and orf163). The fOg44 endolysin was established as a secretory protein when expressed in Lactococcus lactis. Orf117 (from fOg44) promoted lysis of Escherichia coli cultures upon induction of a defective lambda Sam7 prophage, but Orf163 (from fOg30) failed to elicit a lysis response in this system. fOg44 and fOgPSU1 were shown to integrate at the 3' end of a tRNA(Glu) and a tRNA(Lys), respectively. Searching the available sequence of the O. oeni MCW genome for attP-like elements, two other tRNA targets could be proposed for prophage establishment. Between the lysis and integration elements, a diverse cluster of genes (absent in phi 10MC) was observed. One common gene in this "lysogenic conversion cluster" was experimentally confirmed as a transcriptional repressor, affecting the expression of a putative permease gene.
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Affiliation(s)
- Carlos São-José
- Centro de Genética e Biologia Molecular e Departamento de Biologia Vegetal, Faculdade de Ciências da Universidade de Lisboa, Ed. ICAT, 1749-016, Lisbon, Portugal
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Lunde M, Blatny JM, Lillehaug D, Aastveit AH, Nes IF. Use of real-time quantitative PCR for the analysis of phiLC3 prophage stability in lactococci. Appl Environ Microbiol 2003; 69:41-8. [PMID: 12513975 PMCID: PMC152469 DOI: 10.1128/aem.69.1.41-48.2003] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Bacteriophages are a common and constant threat to proper milk fermentation. It has become evident that lysogeny is widespread in lactic acid bacteria, and in this work the temperate lactococcal bacteriophage phi LC3 was used as a model to study prophage stability in lactococci. The stability was analyzed in six phi LC3 lysogenic Lactococcus lactis subsp. cremoris host strains when they were growing at 15 and 30 degrees C. In order to perform these analyses, a real-time PCR assay was developed. The stability of the phi LC3 prophage was found to vary with the growth phase of its host L. lactis IMN-C1814, in which the induction rate increased during the exponential growth phase and reached a maximum level when the strain was entering the stationary phase. The maximum spontaneous induction frequency of the phi LC3 prophage varied between 0.32 and 9.1% (28-fold) in the six lysogenic strains. No correlation was observed between growth rates of the host cells and the spontaneous prophage induction frequencies. Furthermore, the level of extrachromosomal phage DNA after induction of the prophage varied between the strains (1.9 to 390%), and the estimated burst sizes varied up to eightfold. These results show that the host cells have a significant impact on the lytic and lysogenic life styles of temperate bacteriophages. The present study shows the power of the real-time PCR technique in the analysis of temperate phage biology and will be useful in work to reveal the impact of temperate phages and lysogenic bacteria in various ecological fields.
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Affiliation(s)
- Merete Lunde
- Laboratory of Microbial Gene Technology, Department of Chemistry and Biotechnology, Agricultural University of Norway, N-1432 Aas, Norway.
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8
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Abstract
Starter cultures for fermented foods are today developed mainly by design rather than by screening. The design principles are based on knowledge of bacterial metabolism and physiology as well as on the interaction with the food product. In the genomics era, we will obtain a wealth of data making design on a rational basis even simpler. The design tools available are food grade tools for genetic, metabolic and protein engineering and an increased use of laboratory automation and high throughput screening methods. The large body of new data will influence the future patterns of regulation. It is currently difficult to predict in what direction the future regulatory requirements will influence innovation in the food industry. It can either become a promoting force for the practical use of biotechnology to make better and safer products, or it can be limiting the use of starter cultures to a few strains with official approval. Successful cultures based on modern technology is expected to be launched in the areas of: probiotics, bioprotection, general improvement of yield and performance for the existing culture market and probably the introduction of cultures for fermenting other food products. A scientific basis for dramatic innovations that could transform the culture industry is currently being established.
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9
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Grath S, van Sinderen D, Fitzgerald G. Bacteriophage-derived genetic tools for use in lactic acid bacteria. Int Dairy J 2002. [DOI: 10.1016/s0958-6946(01)00150-9] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
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10
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Duez C, Zorzi W, Sapunaric F, Amoroso A, Thamm I, Coyette J. The penicillin resistance of Enterococcus faecalis JH2-2r results from an overproduction of the low-affinity penicillin-binding protein PBP4 and does not involve a psr-like gene. MICROBIOLOGY (READING, ENGLAND) 2001; 147:2561-2569. [PMID: 11535796 DOI: 10.1099/00221287-147-9-2561] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
A penicillin-resistant mutant, JH2-2r (MIC 75 microg ml(-1)), was isolated from Enterococcus faecalis JH2-2 (MIC 5 microg ml(-1)) by successive passages on plates containing increasing concentrations of benzylpenicillin. A comparison of the penicillin-binding protein (PBP) profiles in the two strains revealed a more intensely labelled PBP4 in JH2-2r. Because the sequences of the JH2-2 and JH2-2r pbp4 genes were strictly identical, even in their promoter regions, this intensive labelling could only be associated with an overproduction of the low-affinity PBP4. No psr gene analogous to that proposed to act as a regulator of PBP5 synthesis in Enterococcus hirae and Enterococcus faecium could be identified in the vicinity of pbp4 in E. faecalis JH2-2 and JH2-2r. However, a psr-like gene distant from pbp4 was identified. The cloning and sequencing of that psr-like gene from both E. faecalis strains indicated that they were identical. It is therefore postulated that the PBP4 overproduction in E. faecalis JH2-2r results from the modification of an as yet unidentified factor.
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Affiliation(s)
- Colette Duez
- Centre d'Ingénierie des Protéines, Institut de Chimie, B6, Université de Liège, (Sart Tilman), B-4000 Liège, Belgium1
| | - Willy Zorzi
- Centre d'Ingénierie des Protéines, Institut de Chimie, B6, Université de Liège, (Sart Tilman), B-4000 Liège, Belgium1
| | - Frédéric Sapunaric
- Centre d'Ingénierie des Protéines, Institut de Chimie, B6, Université de Liège, (Sart Tilman), B-4000 Liège, Belgium1
| | - Ana Amoroso
- Centre d'Ingénierie des Protéines, Institut de Chimie, B6, Université de Liège, (Sart Tilman), B-4000 Liège, Belgium1
| | - Iris Thamm
- Centre d'Ingénierie des Protéines, Institut de Chimie, B6, Université de Liège, (Sart Tilman), B-4000 Liège, Belgium1
| | - Jacques Coyette
- Centre d'Ingénierie des Protéines, Institut de Chimie, B6, Université de Liège, (Sart Tilman), B-4000 Liège, Belgium1
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11
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Genetic labeling of lactobacilli in a food grade manner for strain-specific detection of industrial starters and probiotic strains. Food Microbiol 2001. [DOI: 10.1006/fmic.2001.0402] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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12
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Brøndsted L, Ostergaard S, Pedersen M, Hammer K, Vogensen FK. Analysis of the complete DNA sequence of the temperate bacteriophage TP901-1: evolution, structure, and genome organization of lactococcal bacteriophages. Virology 2001; 283:93-109. [PMID: 11312666 DOI: 10.1006/viro.2001.0871] [Citation(s) in RCA: 70] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
A complete analysis of the entire genome of the temperate lactococcal bacteriophage TP901-1 has been performed and the function of 21 of 56 TP901-1-encoded ORFs has been assigned. This knowledge has been used to propose 10 functional modules each responsible for specific functions during bacteriophage TP901-1 proliferation. Short regions of microhomology in intergenic regions present in several lactococcal bacteriophages and chromosomal fragments of Lactococcus lactis are suggested to be points of exchange of genetic material through homologous recombination. Our results indicate that TP901-1 may have evolved by homologous recombination between the host chromosome and a mother phage and support the observation that phage remnants as well as prophages located in the Lactococcus chromosome contribute significantly to bacteriophage evolution. Some proteins encoded in the early transcribed region of the TP901-1 genome were more homologous to proteins encoded by phages infecting gram-positive hosts other than L. lactis. This protein homology argues for the occurrence of horizontal genetic exchange among these bacteriophages and indicates that they have access to a common gene pool.
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Affiliation(s)
- L Brøndsted
- Department of Microbiology, Technical University of Denmark, DK-2800 Lyngby, Denmark.
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Gaeng S, Scherer S, Neve H, Loessner MJ. Gene cloning and expression and secretion of Listeria monocytogenes bacteriophage-lytic enzymes in Lactococcus lactis. Appl Environ Microbiol 2000; 66:2951-8. [PMID: 10877791 PMCID: PMC92096 DOI: 10.1128/aem.66.7.2951-2958.2000] [Citation(s) in RCA: 113] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2000] [Accepted: 04/17/2000] [Indexed: 11/20/2022] Open
Abstract
Bacteriophage lysins (Ply), or endolysins, are phage-encoded cell wall lytic enzymes which are synthesized late during virus multiplication and mediate the release of progeny virions. Bacteriophages of the pathogen Listeria monocytogenes encode endolysin enzymes which specifically hydrolyze the cross-linking peptide bridges in Listeria peptidoglycan. Ply118 is a 30.8-kDa L-alanoyl-D-glutamate peptidase and Ply511 (36.5 kDa) acts as N-acetylmuramoyl-L-alanine amidase. In order to establish dairy starter cultures with biopreservation properties against L. monocytogenes contaminations, we have introduced ply118 and ply511 into Lactococcus lactis MG1363 by using a pTRKH2 backbone. The genes were expressed under control of the lactococcal promoter P32, which proved superior to other promoters (P21 and P59) tested in this study. High levels of active enzymes were produced and accumulated in the cytoplasmic cell fractions but were not released from the cells at significant levels. Therefore, ply511 was genetically fused with the (SP)slpA nucleotide sequence encoding the Lactobacillus brevis S-layer protein signal peptide. Expression of (SP)slpA-ply511 from pSL-PL511 resulted in secretion of functional Ply511 enzyme from L. lactis cells. One clone expressed an unusually strong lytic activity, which was found to be due to a 115-bp deletion that occurred within the 3'-end coding sequence of (SP)slpA-ply511, which caused a frameshift mutation and generated a stop codon. Surprisingly, the resulting carboxy-terminal deletion of 80 amino acids in the truncated Ply511 Delta(S262-K341) mutant polypeptide strongly increased its lytic activity. Proteolytic processing of the secretion competent (SP)SlpA-Ply511 propeptide following membrane translocation had no influence on enzyme activity. Immunoblotting experiments using both cytoplasmic and supernatant fractions indicated that the enzyme was quantitatively exported from the cells and secreted into the surrounding medium, where it caused rapid lysis of L. monocytogenes cells. Moreover, transformation of pSL-PL511 delta C into L. lactis Bu2-129, a lactose-utilizing strain that can be employed for fermentation of milk, also resulted in secretion of functional enzyme and showed that the vector is compatible with the native lactococcal plasmids.
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Affiliation(s)
- S Gaeng
- Institut für Mikrobiologie, FML Weihenstephan, Technische Universität München, D-85350 Freising, Germany
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Martín MC, Alonso JC, Suárez JE, Alvarez MA. Generation of food-grade recombinant lactic acid bacterium strains by site-specific recombination. Appl Environ Microbiol 2000; 66:2599-604. [PMID: 10831443 PMCID: PMC110586 DOI: 10.1128/aem.66.6.2599-2604.2000] [Citation(s) in RCA: 59] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The construction of a delivery and clearing system for the generation of food-grade recombinant lactic acid bacterium strains, based on the use of an integrase (Int) and a resolvo-invertase (beta-recombinase) and their respective target sites (attP-attB and six, respectively) is reported. The delivery system contains a heterologous replication origin and antibiotic resistance markers surrounded by two directly oriented six sites, a multiple cloning site where passenger DNA could be inserted (e.g., the cI gene of bacteriophage A2), the int gene, and the attP site of phage A2. The clearing system provides a plasmid-borne gene encoding beta-recombinase. The nonreplicative vector-borne delivery system was transformed into Lactobacillus casei ATCC 393 and, by site-specific recombination, integrated as a single copy in an orientation- and Int-dependent manner into the attB site present in the genome of the host strain. The transfer of the clearing system into this strain, with the subsequent expression of the beta-recombinase, led to site-specific DNA resolution of the non-food-grade DNA. These methods were validated by the construction of a stable food-grade L. casei ATCC 393-derived strain completely immune to phage A2 infection during milk fermentation.
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Affiliation(s)
- M C Martín
- Departamento de Biología Funcional, Area Microbiología and Instituto Universitario de Biotecnología de Asturias, Universidad de Oviedo, 33006 Oviedo, Spain
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15
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Brøndsted L, Hammer K. Use of the integration elements encoded by the temperate lactococcal bacteriophage TP901-1 to obtain chromosomal single-copy transcriptional fusions in Lactococcus lactis. Appl Environ Microbiol 1999; 65:752-8. [PMID: 9925612 PMCID: PMC91091 DOI: 10.1128/aem.65.2.752-758.1999] [Citation(s) in RCA: 62] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Previously we showed that only one phage-expressed protein (Orf1), a 425-bp region upstream of the orf1 gene (presumably encoding a promoter), and the attP region are necessary and also sufficient for integration of the bacteriophage TP901-1 genome into the chromosome of Lactococcus lactis subsp. cremoris (B. Christiansen, L. Brondsted, F. K. Vogensen, and K. Hammer, J. Bacteriol. 178:5164-5173, 1996). In this work, a further analysis of the phage-encoded elements involved in integration was performed. Here we demonstrate that even when the orf1 gene is separated from the attP region, the Orf1 protein is able to promote site-specific integration of an attP-carrying plasmid into the attB site on the L. lactis subsp. cremoris chromosome. Furthermore, the first detailed deletion analysis of an attP region of a phage infecting lactic acid bacteria was carried out. We show that a fragment containing 56 bp of the attP region, including the core, is sufficient for the site-specific integration of a nonreplicating plasmid into the chromosome of L. lactis subsp. cremoris when the orf1 gene is donated in trans. The functional 56-bp attP region of TP901-1 is substantially smaller than minimal attP regions identified for other phages. Based on the deletion analysis, several repeats located within the attP region seem to be necessary for site-specific integration of the temperate bacteriophage TP901-1. By use of the integrative elements (attP and orf1) expressed by the temperate lactococcal bacteriophage TP901-1, a system for obtaining stable chromosomal single-copy transcriptional fusions in L. lactis was constructed. Two promoter-reporter integration vectors containing the reporter gene gusA or lacLM, encoding beta-glucuronidase or beta-galactosidase, respectively, were constructed. Immediately upstream of both genes are found translational stop codons in all three reading frames as well as multiple restriction enzyme sites suitable for cloning of the promoter of interest. By transformation of L. lactis subsp. cremoris MG1363 containing the integrase gene on a replicating plasmid, the promoter-reporter integration vectors integrated with a high frequency site specifically into the chromosomal attachment site attB used by bacteriophage TP901-1.
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Affiliation(s)
- L Brøndsted
- Department of Microbiology, Technical University of Denmark, DK-2800 Lyngby, Denmark
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16
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Parreira R, São-José C, Isidro A, Domingues S, Vieira G, Santos MA. Gene organization in a central DNA fragment of Oenococcus oeni bacteriophage fOg44 encoding lytic, integrative and non-essential functions. Gene 1999; 226:83-93. [PMID: 9889328 DOI: 10.1016/s0378-1119(98)00554-x] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
The nucleotide sequence of a DNA fragment previously shown to contain the attachment site (attP) of Oenococcus oeni phage fOg44 (. Arch. Virol. 143, 523-536) has been determined. Sequence analysis indicated that this 6226bp EcoRI fragment harbours an integrase gene, in the vicinity of a direct repeat rich region defining attP, as well as genes encoding a muramidase-related lysin (Lys) and a holin polypeptide (Hol). Transcriptional studies suggested that lys and hol are mainly co-expressed, late in the lytic cycle, from a promotor located upstream of lys. Between the lytic cassette and the phage integration elements three additional open reading frames were found: orf217 and orf252 of unknown function and orf72, the putative product of which bears 32% identity with acidic excisionases from other Gram positive phages. We have established that the first two orfs, as well as the predicted promotor of orf72, are included in a 2143-bp DNA segment missing from the genome of the deletion mutant fOg44Delta2. Although lysogens of fOg44 and fOg44Delta2 exhibited similar properties, each phage produced two distinguishable types of lysogenic strains, differing in inducibility and immunity to other oenophages.
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Affiliation(s)
- R Parreira
- Departmento de Biologia Vegetal, Faculdade de Ciências da Universidade de Lisboa, Campo-Grande, 1700, Lisbon, Portugal
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Smith MCM, Rees CED. 3 Exploitation of Bacteriophages and their Components. METHODS IN MICROBIOLOGY 1999. [DOI: 10.1016/s0580-9517(08)70114-4] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
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18
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Frère J, Benachour A, Giard JC, Laplace JM, Flahaut S, Auffray Y. A new theta-type thermosensitive replicon from Lactococcus lactis as an integration vector for Enterococcus faecalis. FEMS Microbiol Lett 1998; 161:107-14. [PMID: 9561737 DOI: 10.1111/j.1574-6968.1998.tb12935.x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Abstract
We isolated a replication thermosensitive mutant of the theta-type lactococcal pUCL22 replicon. An improved version of this thermosensitive replicon was obtained by fusioning the replication repA gene with the downstream repB gene. The resulting plasmid was named pUCB3522Ts. It is highly instable at 42 degrees C in Enterococcus faecalis. Integration into the chromosome via homologous recombination was monitored using the npr gene of E. faecalis JH2-2 as a target. A 513 bp PCR amplification product from an internal region of this npr gene was cloned into pUCB3522Ts. Integration of this construction into the JH2-2 npr gene was selected by shift temperature, from 30 degrees C to 42 degrees C. 85% of the analysed clones showed integration into the npr gene, demonstrating the practicality of this thermosensitive replicon as a genetic integrative tool for E. faecalis.
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Affiliation(s)
- J Frère
- Laboratoire de Microbiologie de l'Environnement, IRBA, Université de Caen, France.
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