1
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Dorau R, Liu J, Solem C, Jensen PR. Metabolic Engineering of Lactic Acid Bacteria. Metab Eng 2021. [DOI: 10.1002/9783527823468.ch15] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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2
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Kok J, van Gijtenbeek LA, de Jong A, van der Meulen SB, Solopova A, Kuipers OP. The Evolution of gene regulation research in Lactococcus lactis. FEMS Microbiol Rev 2018; 41:S220-S243. [PMID: 28830093 DOI: 10.1093/femsre/fux028] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2017] [Accepted: 06/15/2017] [Indexed: 11/12/2022] Open
Abstract
Lactococcus lactis is a major microbe. This lactic acid bacterium (LAB) is used worldwide in the production of safe, healthy, tasteful and nutritious milk fermentation products. Its huge industrial importance has led to an explosion of research on the organism, particularly since the early 1970s. The upsurge in the research on L. lactis coincided not accidentally with the advent of recombinant DNA technology in these years. The development of methods to take out and re-introduce DNA in L. lactis, to clone genes and to mutate the chromosome in a targeted way, to control (over)expression of proteins and, ultimately, the availability of the nucleotide sequence of its genome and the use of that information in transcriptomics and proteomics research have enabled to peek deep into the functioning of the organism. Among many other things, this has provided an unprecedented view of the major gene regulatory pathways involved in nitrogen and carbon metabolism and their overlap, and has led to the blossoming of the field of L. lactis systems biology. All of these advances have made L. lactis the paradigm of the LAB. This review will deal with the exciting path along which the research on the genetics of and gene regulation in L. lactis has trodden.
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Affiliation(s)
- Jan Kok
- Department of Molecular Genetics, Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen, 9747 AG Groningen, the Netherlands
| | - Lieke A van Gijtenbeek
- Department of Molecular Genetics, Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen, 9747 AG Groningen, the Netherlands
| | - Anne de Jong
- Department of Molecular Genetics, Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen, 9747 AG Groningen, the Netherlands
| | - Sjoerd B van der Meulen
- Department of Molecular Genetics, Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen, 9747 AG Groningen, the Netherlands
| | - Ana Solopova
- Department of Molecular Genetics, Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen, 9747 AG Groningen, the Netherlands
| | - Oscar P Kuipers
- Department of Molecular Genetics, Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen, 9747 AG Groningen, the Netherlands
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3
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Streptococcus thermophilus, an emerging and promising tool for heterologous expression: Advantages and future trends. Food Microbiol 2015; 53:2-9. [PMID: 26611164 DOI: 10.1016/j.fm.2015.05.003] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2014] [Revised: 05/07/2015] [Accepted: 05/09/2015] [Indexed: 11/19/2022]
Abstract
Streptococcus thermophilus is the second most used bacterium in dairy industry. It is daily consumed by millions of people through the worldwide consumption of yogurts, cheeses and fermented milks. S. thermophilus presents many features that make it a good candidate for the production of heterologous proteins. First, its ability to be naturally transformable allows obtaining swiftly and easily recombinant strains using various genetic tools available. Second, its Generally Recognised As Safe status and its ability to produce beneficial molecules or to liberate bioactive peptides from milk proteins open up the way for the development of new functional foods to maintain health and well-being of consumers. Finally, its ability to survive the intestinal passage and to be metabolically active in gastrointestinal tract allows considering S. thermophilus as a potential tool for delivering various biological molecules to the gastrointestinal tract. The aim of this review is therefore to take stock of various genetic tools which can be employed in S. thermophilus to produce heterologous proteins and to highlight the advantages and future trends of use of this bacterium as a heterologous expression host.
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4
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Abstract
This article describes my early life and the chance events leading to my becoming a microbiologist and then my embarking on a career developing the plasmid biology and genetics of lactococci used in milk fermentations.
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Affiliation(s)
- Larry McKay
- Department of Food Science and Nutrition, University of Minnesota, St. Paul, Minnesota 55108
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5
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Woskow SA, Kondo JK. Effect of Proteolytic Enzymes on Transfection and Transformation of Streptococcus lactis Protoplasts. Appl Environ Microbiol 2010; 53:2583-7. [PMID: 16347474 PMCID: PMC204149 DOI: 10.1128/aem.53.10.2583-2587.1987] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
With both chymotrypsin and mutanolysin used to form protoplasts, consistent transformation frequencies of 10 to 10 transformants and transfectants per mug of DNA were achieved. The procedure was used to transform protoplasts of Streptococcus cremoris CS224 at low frequency (5 transformants per mug of DNA).
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Affiliation(s)
- S A Woskow
- Department of Nutrition and Food Sciences, Utah State University, Logan, Utah 84322-8700
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6
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Sing WD, Klaenhammer TR. Conjugal Transfer of Bacteriophage Resistance Determinants on pTR2030 into Streptococcus cremoris Strains. Appl Environ Microbiol 2010; 51:1264-71. [PMID: 16347085 PMCID: PMC239056 DOI: 10.1128/aem.51.6.1264-1271.1986] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Agar surface conjugal matings were used to introduce heat-sensitive phage resistance (Hsp) determinants carried on the conjugal plasmid pTR2030 into Streptococcus cremoris KH, HP, 924, and TDM1. Lactose-fermenting (Lac) transconjugants were selected from matings of Lac variants of S. cremoris KH, HP, 924, and TDM1 with Streptococcus lactis ME2 or a high-frequency donor, S. lactis T-EK1 (pTR1040, Lac; pTR2030, Hsp). For all of the S. cremoris strains examined, select Lac transconjugants were completely resistant to plaquing by their homologous lytic phages. In all cases the plaquing efficiencies were less than 10. Acquisition of a 30-megadalton plasmid (pTR2030) in the S. cremoris phage-resistant transconjugants was demonstrated by direct plasmid analysis, by hybridization with P-labeled probes, or by conjugal transfer of pTR2030 out of the phage-resistant transconjugants into a plasmid-cured recipient, S. lactis LM2302. Acid production, coagulation ability, and proteolytic activity of phage-resistant transconjugants in milk were comparable to those of their phage-sensitive parents. Further, S. cremoris phage-resistant transconjugants were not attacked by phage in starter culture activity tests, which included a 40 degrees C incubation period. The results demonstrated that phage resistance determinants on pTR2030 could be conjugally transferred to a variety of S. cremoris strains and confer resistance to phage under conditions encountered during cheese manufacture. Phage-resistant transconjugants of S. cremoris M43 and HP were also constructed without the use of antiblotic markers to select conjugal recipients from mating mixtures.
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Affiliation(s)
- W D Sing
- Department of Food Science, North Carolina State University, Raleigh, North Carolina 27695-7624
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7
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Gonzalez CF, Kunka BS. Evidence for Plasmid Linkage of Raffinose Utilization and Associated alpha-Galactosidase and Sucrose Hydrolase Activity in Pediococcus pentosaceus. Appl Environ Microbiol 2010; 51:105-9. [PMID: 16346958 PMCID: PMC238824 DOI: 10.1128/aem.51.1.105-109.1986] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The ability to ferment the trisaccharide raffinose was linked with the presence of plasmid DNA in three strains of Pediococcus pentosaceus. Parental strains showed associated inducible alpha-galactosidase and sucrose hydrolase activities when grown in alpha-galactosides and sucrose, respectively. Derivative strains of PPE1.0, PPE2.0, and PPE5.0, which had lost 30-, 28-, and 23-megadalton plasmids, respectively, had no alpha-galactosidase or sucrose hydrolase activity.
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8
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van der Lelie D, van der Vossen JM, Venema G. Effect of Plasmid Incompatibility on DNA Transfer to Streptococcus cremoris. Appl Environ Microbiol 2010; 54:865-71. [PMID: 16347608 PMCID: PMC202565 DOI: 10.1128/aem.54.4.865-871.1988] [Citation(s) in RCA: 57] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Several Streptococcus cremoris strains were used in protoplast transformation and interspecific protoplast fusion experiments with Streptococcus lactis and Bacillus subtilis, with pGKV110, pGKV21, and DeltapAMbeta1 as the marker plasmids. DeltapAMbeta1 is a 15.9-kilobase nonconjugative, deletion derivative of pAMbeta1, which is considerably larger than the pGKV plasmids (approximately 4.5 kilobases). In general, DeltapAMbeta1 was transferred more efficiently than the pGKV plasmids. Using electroporation, we were able to demonstrate that failure of efficient transfer for the pGKV plasmids was, except for one case, caused by incompatibility of these plasmids with resident plasmids of the recipient strain.
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Affiliation(s)
- D van der Lelie
- Department of Genetics, University of Groningen, 9751NN Haren, The Netherlands
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9
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Renault PP, Heslot H. Selection of Streptococcus lactis Mutants Defective in Malolactic Fermentation. Appl Environ Microbiol 2010; 53:320-4. [PMID: 16347282 PMCID: PMC203659 DOI: 10.1128/aem.53.2.320-324.1987] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
An enrichment medium and a new sensitive medium were developed to detect malolactic variants in different strains of lactic bacteria. Factors such as the concentration of glucose and l-malate, pH level, and the type of indicator dye used are discussed with regard to the kinetics of malic acid conversion to lactic acid. Use of these media allowed a rapid and easier screening of mutagenized streptococcal cells unable to ferment l-malate. A collection of malolactic-negative mutants of Streptococcus lactis induced by UV, nitrosoguanidine, or transposonal mutagenesis were characterized. The results showed that several mutants were apparently defective in the structural gene of malolactic enzyme, whereas others contained mutations which may either inactivate a putative permease or affect a regulatory sequence.
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Affiliation(s)
- P P Renault
- Laboratoire de Génétique, I. N. A. P.-G., 75231 Paris Cédex 05, France
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10
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Affiliation(s)
- S.K. Harlander
- a Department of Food Science and Nutrition , University of Minnesota , St. Paul , MN , 55108 , USA
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11
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Rattanachaikunsopon P, Phumkhachorn P. Glass bead transformation method for gram-positive bacteria. BRAZILIAN JOURNAL OF MICROBIOLOGY : [PUBLICATION OF THE BRAZILIAN SOCIETY FOR MICROBIOLOGY] 2009; 40:923-6. [PMID: 24031442 PMCID: PMC3768579 DOI: 10.1590/s1517-838220090004000025] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/10/2009] [Revised: 04/26/2009] [Accepted: 03/15/2009] [Indexed: 11/21/2022]
Abstract
A simple, inexpensive and reproducible transformation method was developed for Gram-positive bacteria. It was based on agitation of bacterial protoplasts with glass beads in the presence of DNA and polyethylene glycol. By using this method, introduction of pGK12 into protoplasts of several strains of Gram-positive bacteria was achieved.
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Affiliation(s)
- Pongsak Rattanachaikunsopon
- Department of Biological Science, Ubon Ratchathani University , Warin Chamrap, Ubon Ratchathani 34190 , Thailand
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12
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Guimarães V, Innocentin S, Chatel JM, Lefèvre F, Langella P, Azevedo V, Miyoshi A. A new plasmid vector for DNA delivery using lactococci. GENETIC VACCINES AND THERAPY 2009; 7:4. [PMID: 19208231 PMCID: PMC2646724 DOI: 10.1186/1479-0556-7-4] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/15/2008] [Accepted: 02/10/2009] [Indexed: 11/10/2022]
Abstract
BACKGROUND The use of food-grade lactococci as bacterial carriers to DNA delivery into epithelial cells is a new strategy to develop live oral DNA vaccine. Our goal was to develop a new plasmid, named pValac, for antigen delivery for use in lactococci. The pValac plasmid was constructed by the fusion of: i) a eukaryotic region, allowing the cloning of an antigen of interest under the control of the pCMV eukaryotic promoter to be expressed by a host cell and ii) a prokaryotic region allowing replication and selection of bacteria. In order to evaluate pValac functionality, the gfp ORF was cloned into pValac (pValac:gfp) and was analysed by transfection in PK15 cells. The applicability of pValac was demonstrated by invasiveness assays of Lactococcus lactis inlA+ strains harbouring pValac:gfp into Caco-2 cells. RESULTS After transfection with pValac:gfp, we observed GFP expression in PK15 cells. L. lactis inlA+ were able to invade Caco-2 cells and delivered a functional expression cassette (pCMV:gfp) into epithelial cells. CONCLUSION We showed the potential of an invasive L. lactis harbouring pValac to DNA delivery and subsequent triggering DNA expression by epithelial cells. Further work will be to examine whether these strains are able to deliver DNA in intestinal cells in vivo.
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Affiliation(s)
- Valeria Guimarães
- Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais (ICB-UFMG), Belo Horizonte - MG, Brasil.
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13
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Imanaka T. Application of recombinant DNA technology to the production of useful biomaterials. ADVANCES IN BIOCHEMICAL ENGINEERING/BIOTECHNOLOGY 2005; 33:1-27. [PMID: 2944355 DOI: 10.1007/bfb0002451] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
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14
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Luo H, Wan K, Wang HH. High-frequency conjugation system facilitates biofilm formation and pAMbeta1 transmission by Lactococcus lactis. Appl Environ Microbiol 2005; 71:2970-8. [PMID: 15932992 PMCID: PMC1151824 DOI: 10.1128/aem.71.6.2970-2978.2005] [Citation(s) in RCA: 54] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The importance of conjugation as a mechanism to spread biofilm determinants among microbial populations was illustrated with the gram-positive bacterium Lactococcus lactis. Conjugation triggered the enhanced expression of the clumping protein CluA, which is a main biofilm attribute in lactococci. Clumping transconjugants further transmitted the biofilm-forming elements among the lactococcal population at a much higher frequency than the parental non-clumping donor. This cell-clumping-associated high-frequency conjugation system also appeared to serve as an internal enhancer facilitating the dissemination of the broad-host-range drug resistance gene-encoding plasmid pAMbeta1 within L. lactis, at frequencies more than 10,000 times higher than those for the non-clumping parental donor strain. The implications of this finding for antibiotic resistance gene dissemination are discussed.
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Affiliation(s)
- Hongliang Luo
- Department of Food Science and Technology, The Ohio State University, Columbus, Ohio 43210, USA
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15
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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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16
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Vaid A, Bishop AH. Amplification of fluorescently labelled DNA within gram-positive and acid-fast bacteria. J Microbiol Methods 1999; 38:53-62. [PMID: 10520585 DOI: 10.1016/s0167-7012(99)00078-0] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Representative organisms from a variety of Gram-positive genera were subjected to varying regimes in order to optimise the intracellular amplification of DNA. The bacteria were subjected to treatments with paraformaldehyde, muramidases and mild acid hydrolysis to discover which regime made each organism permeable to the amplification reagents yet allowed retention of the fluorescein-labelled amplified products within the cell. Scanning electron micrographs were used to corroborate the effectiveness of the treatments, as seen by fluorescent photomicrographs, with the damage caused to the bacterial walls. A combination of mutanolysin and lysozyme was found most effective for Bacillus cereus, whereas permeabilisation of Streptomyces coelicolor, Lactococcus lactis and Clostridium sporogenes was most effective when exposed to lysozyme only. Surprisingly, direct amplification with no pre-treatment gave the brightest fluorescence in Mycobacterium phlei. Comparing the techniques of whole cell PCR, primed in situ labelling (PRINS), and cycle PRINS showed that under the conditions used the strongest intensity of fluorescence was obtained with in situ PCR; only L. lactis and M. phlei produced signals with cycle PRINS, fluorescence was not seen for any of the organisms with PRINS.
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Affiliation(s)
- A Vaid
- School of Chemical and Life Sciences, University of Greenwich, London, UK
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17
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Broadbent JR, Sandine WE, Kondo JK. Characteristics of Tn5307 exchange and intergeneric transfer of genes associated with nisin production. Appl Microbiol Biotechnol 1995; 44:139-46. [PMID: 8579827 DOI: 10.1007/bf00164493] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Transfer of the Lactococcus lactis 11454 nisin-sucrose conjugative transposon, Tn5307, was investigated to develop a methodology for conjugation of this element to other lactic acid bacteria. Tn5307 exchange was sensitive to temperature and pH but was not affected by protease or amylase treatments to donor cells. Moreover, conjugation studies demonstrated that the direct-plate method could be employed to rapidly identify LM2301 transconjugants able to transfer Tn5307 at least ten times more efficiently than 11454. Intergeneric transfer of nisin and sucrose genes between L. lactis and a dairy Enterococcus sp. was also investigated. Erythromycin-resistant Enterococcus sp. recipients were developed by electro-transformation with pGK13 or by conjugal introduction of the broad-host-range plasmid pAM beta 1. Matings between L. lactis 11454 and an Enterococcus sp. recipient that contained pAM beta 1 yielded sucrose-positive, nisin-immune transconjugants at a frequency of 2.3 x 10(-9) transconjugants per donor cfu. Agar-overlay assays for nisin production revealed that enterococcal transconjugants did not produce the bacteriocin, but DNA.DNA hybridization with a nisA-specific probe demonstrated that these bacteria had acquired the nisin structural gene.
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Affiliation(s)
- J R Broadbent
- Department of Nutrition and Food Sciences, Utah State University, Logan 84322-8700, USA
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18
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Abstract
Lactose utilization is the primary function of lactic acid bacteria used in industrial dairy fermentations. The mechanism by which lactose is transported determines largely the pathway for the hydrolysis of the internalized disaccharide and the fate of the glucose and galactose moieties. Biochemical and genetic studies have indicated that lactose can be transported via phosphotransferase systems, transport systems dependent on ATP binding cassette proteins, or secondary transport systems including proton symport and lactose-galactose antiport systems. The genetic determinants for the group translocation and secondary transport systems have been identified in lactic acid bacteria and are reviewed here. In many cases the lactose genes are organized into operons or operon-like structures with a modular organization, in which the genes encoding lactose transport are tightly linked to those for lactose hydrolysis. In addition, in some cases the genes involved in the galactose metabolism are linked to or co-transcribed with the lactose genes, suggesting a common evolutionary pathway. The lactose genes show characteristic configurations and very high sequence identity in some phylogenetically distant lactic acid bacteria such as Leuconostoc and Lactobacillus or Lactococcus and Lactobacillus. The significance of these results for the adaptation of lactic acid bacteria to the industrial milk environment in which lactose is the sole energy source is discussed.
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Affiliation(s)
- W M de Vos
- Department of Biophysical Chemistry, NIZO, Ede, The Netherlands
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19
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Beimfohr C, Krause A, Amann R, Ludwig W, Schleifer KH. In situ Identification of Lactococci, Enterococci and Streptococci. Syst Appl Microbiol 1993. [DOI: 10.1016/s0723-2020(11)80279-1] [Citation(s) in RCA: 96] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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20
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Cotransformation of lactococcin-producing, 2.0-mega dalton and erythromycin-resistant pGB 301 plasmids toLactococcus lactis subsp.lactis protoplast. Curr Microbiol 1993. [DOI: 10.1007/bf01692878] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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21
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Wells JM, Wilson PW, Le Page RW. Improved cloning vectors and transformation procedure for Lactococcus lactis. THE JOURNAL OF APPLIED BACTERIOLOGY 1993; 74:629-36. [PMID: 8349525 DOI: 10.1111/j.1365-2672.1993.tb05195.x] [Citation(s) in RCA: 170] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
Four shuttle vectors (pMIG 1, 2, 2H and 3) have been constructed based on the broad host-range plasmid pCK1. All the pMIG vectors possess a multiple cloning site containing 12 or more unique restriction enzyme sites, and are stably maintained at either high or low copy number in Lactococcus lactis and in Escherichia coli. By cloning the E. coli pUC replicon into one of these vectors a plasmid was constructed which can replicate to high copy number in recA strains of E. coli. The broad host-range of the pCK1 replicon may enable these cloning vectors to be used in a number of Gram-positive bacteria. One of these vectors was used to optimize an electroporation procedure for transformation of a commonly used plasmid-cured strain MG1363 of L. lactis which routinely yielded 1 x 10(7) to 5 x 10(7) transformants micrograms-1 supercoiled DNA using stored, snap-frozen cells. This transformation efficiency was obtained by growing the cells in medium containing the cell wall weakening agent glycine, to an upper limit of 2.5% w/v. Although growth of L. lactis strain MG1363 was inhibited by the use of 0.5 mol l-1 sucrose as an osmotic stabilizer, the presence of sucrose in the electroporation buffer was critical for high transformation efficiency. Other variables which were tested for their effect on the efficiency of transformation were cell concentration, DNA concentration, pulse time and field strength. These results provide a model procedure which can be followed to optimize conditions for the genetic transformation of various strains of L. lactis.
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Affiliation(s)
- J M Wells
- Department of Pathology, University of Cambridge, UK
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22
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Sing WD, Klaenhammer TR. A Strategy for Rotation of Different Bacteriophage Defenses in a Lactococcal Single-Strain Starter Culture System. Appl Environ Microbiol 1993; 59:365-72. [PMID: 16348864 PMCID: PMC202114 DOI: 10.1128/aem.59.2.365-372.1993] [Citation(s) in RCA: 55] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
A new strategy for starter culture rotations was developed for a series of phage-resistant clones genetically derived from a single strain of
Lactococcus lactis
subsp.
lactis.
Phage-resistant derivatives carrying different defense systems were constructed via conjugation with various plasmids encoding abortive infection (Abi/Hsp) and/or restriction and modification (R/M) systems of different specificity. The plasmids included pTR2030 (Hsp
+
R
+
/M
+
), pTN20 (Abi
+
R
+
/M
+
), pTRK11 (R
+
/M
+
), and pTRK68 (R
+
/M
+
). Selected phage-resistant transconjugants or transformants were evaluated in different rotation sequences through cycles of the Heap-Lawrence starter culture activity test in milk contaminated with phage and whey from the previous cycle. When used in consecutive sequence, derivative strains carrying the R/M systems encoded by pTN20, pTRK11, and pTRK68 retarded phage development when the initial levels of phage contamination were below 10
2
PFU/ml but not when levels were increased to 10
3
PFU/ml. Use of a derivative bearing pTR2030 (Hsp
+
R
+
/M
+
) at the beginning of the rotation prevented phage development, even when the initial levels of phage contamination were high (10
6
PFU/ml). Alternating the type and specificity of R/M and Abi defenses through the rotation prevented phage proliferation and in some cases eliminated contaminating phages. A model rotation sequence for the phage defense rotation strategy was developed and performed successfully over nine cycles of the Heap-Lawrence starter culture activity test in the presence of high-titer commercial phage composites. This phage defense rotation strategy is designed to protect a highly specialized
Lactococcus
strain from phage attack during continuous and extended use in the dairy industry.
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Affiliation(s)
- W D Sing
- Department of Microbiology, Southeast Dairy Foods Research Center, North Carolina State University, Raleigh, North Carolina 27695-7624
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23
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Durmaz E, Higgins DL, Klaenhammer TR. Molecular characterization of a second abortive phage resistance gene present in Lactococcus lactis subsp. lactis ME2. J Bacteriol 1992; 174:7463-9. [PMID: 1429469 PMCID: PMC207445 DOI: 10.1128/jb.174.22.7463-7469.1992] [Citation(s) in RCA: 61] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
The fifth phage resistance factor from the prototype phage-insensitive strain Lactococcus lactis subsp. lactis ME2 has been characterized and sequenced. The genetic determinant for Prf (phage resistance five) was subcloned from the conjugative plasmid pTN20, which also encodes a restriction and modification system. Typical of other abortive resistance mechanisms, Prf reduces the efficiency of plaquing to 10(-2) to 10(-3) and decreases the plaque size and burst size of the small isometric-headed phage p2 in L. lactis subsp. lactis LM0230. However, normal-size plaques occurred at a frequency of 10(-4) and contained mutant phages that were resistant to Prf, even after repeated propagation through a sensitive host. Prf does not prevent phage adsorption or promote restriction and modification activities, but 90% of Prf+ cells infected with phage p2 die. Thus, phage infections in Prf+ cells are aborted. Prf is effective in both L. lactis subsp. lactis and L. lactis subsp. cremoris strains against several small isometric-headed phages but not against prolate-headed phages. The Prf determinant was localized by Tn5 mutagenesis and subcloning. DNA sequencing identified a 1,056-nucleotide structural gene designated abiC. Prf+ expression was obtained when abiC was subcloned into the lactococcal expression vector pMG36e. abiC is distinct from two other lactococcal abortive phage resistance genes, abiA (Hsp+, from L. lactis subsp. lactis ME2) and abi416 (Abi+, from L. lactis subsp. lactis IL416). Unlike abiA, the action of abiC does not appear to affect DNA replication. Thus, abiC represents a second abortive system found in ME2 that acts at a different point of the phage lytic cycle.
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Affiliation(s)
- E Durmaz
- Department of Food Science North Carolina State University, Raleigh 27695-7624
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24
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Stoddard GW, Petzel JP, van Belkum MJ, Kok J, McKay LL. Molecular analyses of the lactococcin A gene cluster from Lactococcus lactis subsp. lactis biovar diacetylactis WM4. Appl Environ Microbiol 1992; 58:1952-61. [PMID: 1622271 PMCID: PMC195709 DOI: 10.1128/aem.58.6.1952-1961.1992] [Citation(s) in RCA: 103] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
The genes responsible for bacteriocin production and immunity in Lactococcus lactis subsp. lactis biovar diacetylactis WM4 were localized and characterized by DNA restriction fragment deletion, subcloning, and nucleotide sequence analysis. The nucleotide sequence of a 5.6-kb AvaII restriction fragment revealed a cluster with five complete open reading frames (ORFs) in the same orientation. DNA and protein homology analyses, combined with deletion and Tn5 insertion mutagenesis, implicated four of the ORFs in the production of and immunity to lactococcin A. The last two ORFs in the cluster were the lactococcin A structural and immunity genes, lcnA and lciA. The two ORFs immediately upstream of lcnA and lciA were designated lcnC and lcnD, and the proteins that they encoded showed similarities to proteins of signal sequence-independent secretion systems. lcnC encodes a protein of 716 amino acids that could belong to the HlyB family of ATP-dependent membrane translocators. LcnC contains an ATP binding domain in a conserved C-terminal stretch of approximately 200 amino acids and three putative hydrophobic segments in the N terminus. The lcnD product, LcnD, of 474 amino acids, is essential for lactococcin A expression and shows structural similarities to HlyD and its homologs. On the basis of these results, a secretion apparatus that is essential for the full expression of active lactococcin A is postulated.
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Affiliation(s)
- G W Stoddard
- Department of Food Science and Nutrition, University of Minnesota, St. Paul 55108
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25
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Abstract
Lactic acid bacteria are of major economic importance, as they occupy a key position in the manufacture of fermented foods. A considerable body of research is currently being devoted to the development of lactic acid bacterial strains with improved characteristics, that may be used to make fermentations pass of more efficiently, or to make new applications possible. Therefore, and because the lactococci are designated 'GRAS' organisms ('generally recognized as safe') which may be used for safe production of foreign proteins, detailed knowledge of homologous and heterologous gene expression in these organisms is desired. An overview is given of our current knowledge concerning gene expression in Lactococcus lactis. A general picture of gene expression signals in L. lactis emerges that shows considerable similarity to those observed in Escherichia coli and Bacillus subtilis. This feature allowed the expression of a number of L. lactis-derived genes in the latter bacterial species. Several studies have indicated, however, that in spite of the similarities, the expression signals from E. coli, B. subtilis and L. lactis are not equally efficient in these three organisms.
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Affiliation(s)
- M van de Guchte
- Department of Genetics, University of Groningen, Haren, The Netherlands
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26
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Dessart S, Steenson L. High Frequency Intergeneric and Intrageneric Conjugal Transfer of Drug Resistance Plasmids in Leuconostoc mesenteroides ssp. cremoris. J Dairy Sci 1991. [DOI: 10.3168/jds.s0022-0302(91)78474-9] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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27
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Cocconcelli PS, Gasson MJ, Morelli L, Bottazzi V. Single-stranded DNA plasmid, vector construction and cloning of Bacillus stearothermophilus alpha-amylase in Lactobacillus. Res Microbiol 1991; 142:643-52. [PMID: 1961976 DOI: 10.1016/0923-2508(91)90077-n] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Vector plasmids were constructed by ligating chloramphenicol and erythromycin resistance genes to TaqI-digested DNA of a cryptic plasmid from Lactobacillus plantarum. The minimal region of Lactobacillus plasmid DNA that was required for DNA replication was defined and a single-stranded DNA intermediate replication system was observed. Homologies with other origins of replication of plasmids from Gram-positive bacteria, replicating via rolling circle mechanism, were found. It was shown that the constructed vectors, named pPSC20 and pPSC22, were transformable into L. plantarum, Lactobacillus acidophilus, Lactobacillus reuteri, Lactobacillus fermentum, Lactobacillus helveticus, Lactococcus lactis subsp. lactis, Bacillus subtilis, and Escherichia coli. Using plasmid pPSC22, the alpha-amylase gene of Bacillus stearothermophilus was cloned and expressed in several Lactobacillus species.
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Affiliation(s)
- P S Cocconcelli
- Istituto di Microbiologia, Università Cattolica del Sacro Cuore, Piacenza, Italy
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28
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Slos P, Bourquin JC, Lemoine Y, Mercenier A. Isolation and characterization of chromosomal promoters of Streptococcus salivarius subsp. thermophilus. Appl Environ Microbiol 1991; 57:1333-9. [PMID: 1854195 PMCID: PMC182951 DOI: 10.1128/aem.57.5.1333-1339.1991] [Citation(s) in RCA: 44] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
A promoter probe vector, pTG244, was constructed with the aim of isolating transcription initiation signals from Streptococcus thermophilus (Streptococcus salivarius subsp. thermophilus). pTG244 is based on the Escherichia coli-streptococcus shuttle vector pTG222, into which the promoterless chloramphenicol acetyltransferase gene of Bacillus pumilus (cat-86) was cloned. Random Sau3A fragments from the S. thermophilus A054 chromosomal DNA were cloned upstream of the cat-86 gene by using E. coli as the host. The pool of recombinant plasmids were introduced into S. thermophilus and Lactococcus lactis subsp. lactis in order to search for promoter activity in these hosts. For S. thermophilus, it was necessary to first select erythromycin-resistant transformants and then to screen for chloramphenicol resistance among these. Direct selection of chloramphenicol-resistant clones was, however, possible in L. lactis subsp. lactis. Six fragments exhibiting promoter activity were characterized in S. thermophilus by measuring the levels of cat-86 transcription and/or chloramphenicol acetyltransferase specific activity. Three of the promoter-carrying fragments were sequenced. The 5' ends of their corresponding mRNAs were determined by S1 mapping and shown to correspond to a purine residue in all cases. Upstream from these potential transcription start points, sequences homologous to the E. coli sigma 70 and the Bacillus subtilis vegetative sigma 43 (or sigma A) consensus promoters were identified.
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Affiliation(s)
- P Slos
- Transgène S.A., Strasbourg, France
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29
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Sing WD, Klaenhammer TR. Characterization of Restriction-Modification Plasmids from Lactococcus lactis ssp. cremoris and Their EffectsWhen Combined with pTR2030. J Dairy Sci 1991. [DOI: 10.3168/jds.s0022-0302(91)78265-9] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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30
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Influence of the physiological state on the electric field mediated transformation efficiency of intact mycobacterial cells. J Electroanal Chem (Lausanne) 1991. [DOI: 10.1016/0022-0728(91)85633-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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31
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Influence of the physiological state on the electric field mediated transformation efficiency of intact mycobacterial cells. ACTA ACUST UNITED AC 1991. [DOI: 10.1016/0302-4598(91)87009-6] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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32
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Feirtag JM, Petzel JP, Pasalodos E, Baldwin KA, McKay LL. Thermosensitive plasmid replication, temperature-sensitive host growth, and chromosomal plasmid integration conferred by Lactococcus lactis subsp. cremoris lactose plasmids in Lactococcus lactis subsp. lactis. Appl Environ Microbiol 1991; 57:539-48. [PMID: 1901709 PMCID: PMC182745 DOI: 10.1128/aem.57.2.539-548.1991] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
Evidence is presented that lactose-fermenting ability (Lac+) in Lactococcus lactis subsp. cremoris AM1, SK11, and ML1 is associated with plasmid DNA, even though these strains are difficult to cure of Lac plasmids. When the Lac plasmids from these strains were introduced into L. lactis subsp. lactis LM0230, they appeared to replicate in a thermosensitive manner; inheritance of the plasmid was less efficient at 32 to 40 degrees C than at 22 degrees C. The stability of the L. lactis subsp. cremoris Lac plasmids in lactococci appeared to be a combination of both host and plasmid functions. Stabilized variants were isolated by growing the cultures at 32 to 40 degrees C; these variants contained the Lac plasmids integrated into the L. lactis subsp. lactis LM0230 chromosome. In addition, the presence of the L. lactis subsp. cremoris Lac plasmids in L. lactis subsp. lactis resulted in a temperature-sensitive growth response; growth of L. lactis subsp. lactis transformants was significantly inhibited at 38 to 40 degrees C, thereby resembling some L. lactis subsp. cremoris strains with respect to temperature sensitivity of growth.
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Affiliation(s)
- J M Feirtag
- Department of Food Science and Nutrition, University of Minnesota, St. Paul 55108
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33
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Koivula T, Sibakov M, Palva I. Isolation and characterization of Lactococcus lactis subsp. lactis promoters. Appl Environ Microbiol 1991; 57:333-40. [PMID: 1707605 PMCID: PMC182715 DOI: 10.1128/aem.57.2.333-340.1991] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
DNA fragments with promoter activity were isolated from the chromosome of Lactococcus lactis subsp. lactis. For the isolation, a promoter probe vector based on the cat gene was constructed, which allowed direct selection with chloramphenicol in Bacillus subtilis and L. lactis. Four of the putative promoters (P1, P2, P10, and P21) were analyzed further by sequencing, mapping of the 5' end of the mRNA, Northern (RNA blot) hybridization, and chloramphenicol acetyltransferase activity measurements. From these fragments, -10 and -35 regions resembling the consensus Escherichia coli sigma 70 and B. subtilis sigma 43 promoters were identified. Another set of promoters, together with a signal sequence, were also isolated from the same organism. These fragments promoted secretion of TEM beta-lactamase from L. lactis. When the two sets of promoters were compared, it was found that the ones isolated with the cat vector were more efficient (produced more mRNA). By changing the promoter part of the promoter-signal sequence fragment giving the best TEM beta-lactamase secretion into a more efficient one (P2), a 10-fold increase in enzyme production was obtained.
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34
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Iwaki M, Okahashi N, Takahashi I, Kanamoto T, Sugita-Konishi Y, Aibara K, Koga T. Oral immunization with recombinant Streptococcus lactis carrying the Streptococcus mutans surface protein antigen gene. Infect Immun 1990; 58:2929-34. [PMID: 2117575 PMCID: PMC313589 DOI: 10.1128/iai.58.9.2929-2934.1990] [Citation(s) in RCA: 50] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
A recombinant Streptococcus lactis strain which carries the structural gene for a surface protein antigen (PAc) of 190,000 daltons from Streptococcus mutans serotype c was constructed for development of an oral vaccine against dental caries. The gene from S. mutans MT8148 joined to shuttle vector pSA3 was successfully transformed into S. lactis IL1403. A small amount of PAc was detected in the cell homogenate and cytoplasmic fraction of the recombinant S. lactis, but not in the culture supernatant of the recombinant, by Western immunoblotting and dot immunoblotting. The level of PAc-specific mRNA in the recombinant strain was lower than that in S. mutans MT8148. However, significant salivary immunoglobulin A and serum immunoglobulin G responses to PAc were induced in mice immunized orally with the recombinant S. lactis.
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Affiliation(s)
- M Iwaki
- Department of Biomedical Research on Foods, National Institute of Health, Tokyo, Japan
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35
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Abstract
The proteolytic system of lactic acid bacteria is of eminent importance for the rapid growth of these organisms in protein-rich media. The combined action of proteinases and peptidases provides the cell with small peptides and essential amino acids. The amino acids and peptides thus liberated have to be translocated across the cytoplasmic membrane. To that purpose, the cell contains specific transport proteins. The internalized peptides are further degraded to amino acids by intracellular peptidases. The world-wide economic importance of the lactic acid bacteria and their proteolytic system has led to an intensive research effort in this area and a considerable amount of biochemical data has been collected during the last two decades. Since the development of systems to genetically manipulate lactic acid bacteria, data on the genetics of enzymes and processes involved in proteolysis are rapidly being generated. In this review an overview of the latest genetic data on the proteolytic system of lactic acid bacteria will be presented. As most of the work in this field has been done with lactococci, the emphasis will, inevitably, be on this group of organisms. Where possible, links will be made with other species of lactic acid bacteria.
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Affiliation(s)
- J Kok
- Department of Genetics, University of Groningen, Haren, The Netherlands
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36
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37
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Solioz M, Waser M. Efficient electrotransformation of Enterococcus hirae with a new Enterococcus-Escherichia coli shuttle vector. Biochimie 1990; 72:279-83. [PMID: 2116916 DOI: 10.1016/0300-9084(90)90084-t] [Citation(s) in RCA: 24] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
In the present study, an Enterococcus-Escherichia coli shuttle vector, pC3, was constructed that allows efficient transformation by electroporation of Enterococcus hirae ATCC9790. 5 x 10(6) transformants per microgram of plasmid DNA were obtained, using a commercial capacitor discharge device with an improved circuitry and a home-made electrode assembly, delivering pulses of 24 kV/cm across the cell suspension. The transformants were stable without selective pressure and plasmid DNA reisolated from transformed cells displayed no alterations in restriction enzyme analysis. Chromosomal DNA from E coli or E hirae, carried by pC3, was stably maintained in E hirae, making cloning and genetic manipulation in this organism feasible.
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Affiliation(s)
- M Solioz
- Dept of Clinical Pharmacology, University of Berne, Switzerland
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38
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van der Lelie D, Wösten HA, Bron S, Oskam L, Venema G. Conjugal mobilization of streptococcal plasmid pMV158 between strains of Lactococcus lactis subsp. lactis. J Bacteriol 1990; 172:47-52. [PMID: 2104609 PMCID: PMC208399 DOI: 10.1128/jb.172.1.47-52.1990] [Citation(s) in RCA: 24] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
pMV158, a non-self-transmissible plasmid encoding tetracycline resistance, was conjugally transferred from Enterococcus faecalis JH203 to Lactococcus lactis subsp. lactis IL1403. This transfer appeared to be dependent on the cotransfer of the conjugative plasmids pAM beta 1 or pIP501. Intraspecies conjugal transfer of pMV158 also occurred in strain IL1403. In contrast to the transfer from E. faecalis, transfer in IL1403 did not require the presence of a conjugative plasmid in the donor strain but, rather, appeared to be dependent on putative chromosomal functions in strain IL1403. The transfer of pMV158 from strain IL1403 required the presence of an active pMV158-encoded protein, which showed homology to the Pre (plasmid recombination enzyme) proteins encoded by several small plasmids extracted from Staphylococcus aureus, such as pT181.
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Affiliation(s)
- D van der Lelie
- Department of Genetics, University of Groningen, Haren, The Netherlands
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39
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de Vos WM, Vos P, de Haard H, Boerrigter I. Cloning and expression of the Lactococcus lactis subsp. cremoris SK11 gene encoding an extracellular serine proteinase. Gene X 1989; 85:169-76. [PMID: 2515994 DOI: 10.1016/0378-1119(89)90477-0] [Citation(s) in RCA: 104] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
The Lactococcus lactis subsp. cremoris SK11 plasmid-located prtP gene, encoding a cell-envelope-located proteinase (PrtP) that degrades alpha s1-, beta- and kappa-casein, was identified in a lambda EMBL3 gene library in Escherichia coli using immunological methods. The complete prtP gene could not be cloned in E. coli and L. lactis on high-copy-number plasmid vectors. However, using a low-copy-number vector, the complete prtP gene could be cloned in strains MG1363 and SK1128, proteinase-deficient derivatives of L. lactis subsp. lactis 712 and L. lactis subsp. cremoris SK11, respectively. The proteinase deficiency of these hosts was complemented to wild-type (wt) levels by the cloned SK11 prtP gene. The caseinolytic specificity of the proteinase specified by the cloned prtP gene was identical to that encoded by the wt proteinase plasmid, pSK111. The expression of recombinant plasmids containing 3' and 5' deletions of prtP was analyzed with specific attention directed towards the location of the gene products. In this way the expression signals of prtP were localized and overproduction was obtained in L. lactis subsp. lactis. Furthermore, a region at the C terminus of PrtP was identified which is involved in cell-envelope attachment in lactococci. A deletion derivative of prtP was constructed which specifies a C-terminally truncated proteinase that is well expressed and fully secreted into the medium, and still shows the same capacity to degrade alpha s1-, beta- and kappa-casein.
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Affiliation(s)
- W M de Vos
- Department of Biophysical Chemistry, Netherlands Institute for Dairy Research (NIZO), Ede
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40
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41
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42
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43
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McIntyre DA, Harlander SK. Improved electroporation efficiency of intact Lactococcus lactis subsp. lactis cells grown in defined media. Appl Environ Microbiol 1989; 55:2621-6. [PMID: 2513778 PMCID: PMC203134 DOI: 10.1128/aem.55.10.2621-2626.1989] [Citation(s) in RCA: 45] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
The impact of growth conditions on electroporation of Lactococcus lactis subsp. lactis LM0230 (previously designated Streptococcus lactis LM0230) was evaluated. Cells grown in M17 broth supplemented with 0.5% glucose (M17-Glu) and two chemically defined synthetic media, FMC and RPMI 1640, all supplemented with 0.24% DL-threonine or 0.5% glycine, were harvested, washed with double-distilled water, diluted, and porated in the presence of 1 microgram of pGB301 DNA with a Transfector 100 (BTX, Inc., San Diego, Calif.) or a Gene Pulser (Bio-Rad Laboratories, Richmond, Calif.). Transformants were recovered at consistently higher efficiencies for cells grown in FMC or RPMI 1640 (10(3) to 10(4) transformants per micrograms of DNA) than for cells grown in M17-Glu (10(1) to 10(2) transformants per micrograms of DNA). Other parameters influencing electroporation of L. lactis cells grown in chemically defined media were growth phase and final concentration of cells, concentration of plasmid DNA, voltage achieved during poration, and expression conditions. A high degree of variability in transformation efficiencies was evident for replicate samples of cells pulsed with either electroporation machine. A trend toward decreased variability was observed for duplicate samples of cells prepared on the same day. In addition, storage studies done with a large batch of cells prepared on the same day indicated that freezing dry cell pellets at -60 degrees C had no deleterious effect on transformation efficiencies over a 30-day period when a new 0.2-cm cuvette was used for porating each sample.
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Affiliation(s)
- D A McIntyre
- Department of Food Science and Nutrition, University of Minnesota, St. Paul 55108
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44
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McKay LL, Bohanon MJ, Polzin KM, Rule PL, Baldwin KA. Localization of Separate Genetic Loci for Reduced Sensitivity towards Small Isometric-Headed Bacteriophage sk1 and Prolate-Headed Bacteriophage c2 on pGBK17 from
Lactococcus lactis
subsp.
lactis
KR2. Appl Environ Microbiol 1989; 55:2702-9. [PMID: 16348036 PMCID: PMC203147 DOI: 10.1128/aem.55.10.2702-2709.1989] [Citation(s) in RCA: 30] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The mechanism of reduced sensitivity to the small isometric-headed bacteriophage sk1 encoded on a 19-kilobase (kb)
Hpa
II fragment subcloned from pKR223 of
Lactococcus lactis
subsp.
lactis
KR2 was examined. The reduced sensitivity to phage sk1 was due to a modest restriction/modification (R/M) system that was not active against prolate-headed phage c2. The genetic loci for the R/M system against sk1 and the abortive phage infection (Abi) mechanism effective against phage c2 were then localized by restriction mapping, subcloning, and deletion analysis. The restriction gene was localized to a region of a 2.7-kb
Eco
RV fragment and included an
Eco
RI site within that fragment. The modification gene was found to be physically separable from the restriction gene and was present on a 1.75-kb
Bst
EII-
Xba
I fragment. The genetic locus for the Abi phenotype against phage c2 was localized to a region containing a 1.3-kb
Eco
RI fragment. Attempts to clone the c2 Abi mechanism independent of the sk1 R/M system were unsuccessful, suggesting that expression of the
abi
genes required sequences upstream of the modification gene. Some pGBK17 (vector pGB301 plus a 19-kb
Hpa
II insert fragment) transformants exhibited the R/M system against phage sk1 but lost the Abi mechanism against phage c2. These transformants contained a 1.2- to 1.3-kb insertion in the Abi region. The data identified genetic loci on a cloned 19-kb
Hpa
II fragment responsible for restriction activity and for modification activity against a small isometric-headed phage and for Abi activity against prolate-headed phage c2. A putative insertion element was also found to inactivate the
abi
gene(s).
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Affiliation(s)
- L L McKay
- Department of Food Science and Nutrition, University of Minnesota, 1334 Eckles Avenue, St. Paul, Minnesota 55108
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45
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van der Lelie D, Bron S, Venema G, Oskam L. Similarity of minus origins of replication and flanking open reading frames of plasmids pUB110, pTB913 and pMV158. Nucleic Acids Res 1989; 17:7283-94. [PMID: 2677995 PMCID: PMC334808 DOI: 10.1093/nar/17.18.7283] [Citation(s) in RCA: 66] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
Plasmids pMV158 and pTB913, originating from Streptococcus agalactiae and a thermophilic Bacillus respectively, were sequenced to completion. Both contained a BA3-type minus origin of replication and an RSA-site, believed to constitute a site-specific recombination site. These two regions were more than 99% homologous to the corresponding regions of the Staphylococcus aureus plasmid pUB110. Deleting the BA3-type minus origin resulted in the accumulation of a considerable amount of single-stranded DNA, both in L. lactis subsp. lactis and B. subtilis, indicating that this minus origin was functional in both bacterial species. Like pUB110, both plasmids contained an open reading frame encoding a putative plasmid recombination enzyme (Pre protein), which was located downstream of the RSA-site. On the basis of sequence comparisons between pUB110, pMV158, pTB913, pT181, pE194, pNE131 and pT48 two distinct families of RSA-sites and Pre proteins could be distinguished.
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Affiliation(s)
- D van der Lelie
- Department of Molecular Genetics, University of Groningen, Haren, The Netherlands
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46
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Steele JL, Murphy MC, Daly C, McKay LL. DNA-DNA homology among lactose- and sucrose-fermenting transconjugants from Lactococcus lactis strains exhibiting reduced bacteriophage sensitivity. Appl Environ Microbiol 1989; 55:2410-3. [PMID: 2508557 PMCID: PMC203090 DOI: 10.1128/aem.55.9.2410-2413.1989] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
DNA-DNA homology between a reduced bacteriophage sensitivity (Rbs+) probe and DNA from both Rbs+ and Rbs- Lactococcus lactis strains was examined. Homology was detected between the probe and five plasmids (pCI750, pCC34, pEB56, pNP2, and pJS88) isolated from lactose-positive Rbs+ transconjugants and between the probe and genomic DNA of a sucrose-positive Rbs+ transconjugant. Additionally, hybridizations conducted between the probe and plasmids reported to encode abortive bacteriophage infection indicated homology with pTR2030 but not with pBF61 and pGBK17. The results suggest that a common genetic determinant(s) may be present in a variety of lactococcal plasmids coding for Rbs+.
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Affiliation(s)
- J L Steele
- Department of Genetics and Cell Biology, University of Minnesota, St. Paul 55108
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Schurter W, Geiser M, Mathé D. Efficient transformation of Bacillus thuringiensis and B. cereus via electroporation: transformation of acrystalliferous strains with a cloned delta-endotoxin gene. MOLECULAR & GENERAL GENETICS : MGG 1989; 218:177-81. [PMID: 2550762 DOI: 10.1007/bf00330581] [Citation(s) in RCA: 67] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Electroporation was used as a method to transform intact cells of Bacillus thuringiensis and B. cereus. With our optimized method a range of plasmid vectors could be transformed into strains of B. thuringiensis at frequencies of up to 10(7) transformants/micrograms DNA. This high frequency allows cloning experiments to be done directly in B. thuringiensis. A bifunctional vector capable of replicating in Escherichia coli and in Bacillus spp. was constructed. The kurhd1 protoxin gene was cloned into this shuttle vector to produce plasmid pX193, then transformed into B. thuringiensis HD1 cryB and B. cereus 569K. The cloned protoxin gene was expressed in sporulating cultures of both strain HD1 cryB (pX193) and 569K (pXI93), producing crystal protein active in biotests against larvae of Heliothis virescens. This demonstrates the usefulness of the electroporation method for the introduction of cloned toxin genes, in either their native or modified form, into a variety of host strains.
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Affiliation(s)
- W Schurter
- Biotechnology Department, Ciba-Geigy Ltd., Basel, Switzerland
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Abstract
Conjugal transfer of genetic material by Lactococcus lactis subsp. lactis 11007 was examined. A plasmid of 88 MDa (pJS88) was identified in addition to the previously reported conjugally transferred plasmids of 32 (pKB32) and 4.8 MDa. Proteinase activity, reduced bacteriophage sensitivity, bacteriocin resistance, and conjugal transfer ability were encoded by pJS88. The ability to metabolize lactose (Lac+) was encoded by pKB32, and the 4.8-MDa plasmid was cryptic. When a strain containing both pKB32 and pJS88 was mated with a recipient deficient in host-mediated homologous recombination (Rec-), a plasmid of 40 MDa (pJS40) was observed in approximately 50% of the Lac+ transconjugants. DNA-DNA hybridization results indicated that pJS40 contained homology with both pKB32 and pJS88. These results indicated that pKB32 was conjugally transferred via conduction and suggested that pJS40 is a deletion derivative of a pKB32::pJS88 cointegrate. A Rec- strain containing pKB32 and pJS88 mediated Lac+ conjugal transfer, suggesting that the pKB32::pJS88 cointegrate could form via a rec-independent event. Resolution of the pKB32::pJS88 cointegrate was observed in both Rec- and Rec+ hosts. Cointegrate formation and resolution via rec-independent mechanisms suggest the involvement of a transposable element in the Tn3 family.
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Affiliation(s)
- J L Steele
- Department of Genetics and Cell Biology, University of Minnesota, St. Paul 55108
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Hill C, Romero DA, McKenney DS, Finer KR, Klaenhammer TR. Localization, cloning, and expression of genetic determinants for bacteriophage resistance (Hsp) from the conjugative plasmid pTR2030. Appl Environ Microbiol 1989; 55:1684-9. [PMID: 2504114 PMCID: PMC202935 DOI: 10.1128/aem.55.7.1684-1689.1989] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Genetic determinants for a bacteriophage resistance mechanism (Hsp+) encoded by plasmid pTR2030 (46.2 kilobases [kb]) were localized by mapping an 11.5-kb deletion that accompanied the transition of Lactococcus lactis LMA12-4 transconjugants (M. E. Sanders, P. J. Leonard, W. D. Sing, and T. R. Klaenhammer, Appl. Environ. Microbiol. 52:1001-1007, 1986) from phage resistance to phage sensitivity. The deleted 34.7-kb replicon (pTR2023, Hsp-) retained its conjugative ability, demonstrating that the phage resistance and conjugal transfer determinants were genetically distinct. The Hsp region of pTT2030, which was contained within a 13.6-kb BglII fragment, was cloned into the BamHI site of bacteriophage lambda EMBL3, and Hsp was subcloned into the Escherichia coli-Streptococcus shuttle vector pSA3. The recombinant plasmids pTK6 and pTK9 were recovered in E. coli HB101 and contained a 13.6-kb insert in opposite orientations. L. Lactis MG1363 transformants carrying pTK6 or pTK9 exhibited a significant reduction in plaque size, in addition to a slight reduction in the efficiency of plaquing for both prolate and small isometric phages. Phenotypic reactions observed for the recombinant plasmids suggest that pTR2030-encoded Hsp acts similarly against both prolate and small isometric phages. Tn5 mutagenesis was used to define the region essential for the expression of the Hsp+ phenotype. Any of four insertions within a 3-kb region resulted in the loss of phage resistance, whereas a further 26 insertions outside this locus had no effect on Hsp expression. In vitro deletion analysis confirmed that the 3-kb region contained all the information necessary for the observed resistance.
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Affiliation(s)
- C Hill
- Department of Food Science, Southeast Dairy Foods Research Center, North Carolina State University, Raleigh 27695-7624
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David S, Simons G, De Vos WM. Plasmid transformation by electroporation of Leuconostoc paramesenteroides and its use in molecular cloning. Appl Environ Microbiol 1989; 55:1483-9. [PMID: 2504108 PMCID: PMC202890 DOI: 10.1128/aem.55.6.1483-1489.1989] [Citation(s) in RCA: 42] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
In this report, we demonstrate the utility of electroporation as an efficient method for genetic transformation of Leuconostoc paramesenteroides. We optimized several factors which determine the transformation frequency, resulting in transformation efficiencies of up to 4 x 10(3) transformants per micrograms of pNZ12 DNA, which contains the promiscuous Lactococcus lactis pSH71 replicon. Slightly lower efficiencies were obtained with a deletion derivative of the broad-host-range plasmid pAM beta 1. These plasmids could be stably maintained in L. paramesenteroides NZ6009 for more than 100 generations, even in the absence of selective pressure. In order to show the use of the developed host-vector system, we cloned the Lactococcus lactis gene encoding phospho-beta-galactosidase in L. paramesenteroides. Expression of this heterologous gene in L. paramesenteroides under control of Lactococcus lactis expression signals was evident from the presence, in transformants, of phospho-beta-galactosidase activity and a specific phospho-beta-galactosidase protein band on Western blots (immunoblots). In addition, we transformed a lactose-deficient derivative of L. paramesenteroides with a plasmid carrying a Lactococcus lactis-Escherichia coli lacZ gene fusion. The resulting transformants synthesized high levels of beta-galactosidase, indicating the efficiency of heterologous gene expression signals in L. paramesenteroides.
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Affiliation(s)
- S David
- Department of Biophysical Chemistry, Netherlands Institute for Dairy Research (NIZO), BA EDE
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