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Sample records for bacterium lactococcus lactis

  1. Lactococcus lactis - a diploid bacterium

    DEFF Research Database (Denmark)

    Michelsen, Ole; Hansen, Flemming G.; Jensen, Peter Ruhdal

    In contrast to higher eukaryotes, bacteria are haploid, i.e. they store their genetic information in a single chromosome, which is then duplicated during the cell cycle. If the growth rate is sufficiently low, the bacterium is born with only a single copy of the chromosome, which gets duplicated...... before the bacterium divides. Fast-growing bacteria have overlapping rounds of replication, and can contain DNA corresponding to more than four genome equivalents. However, the terminus region of the chromosome is still present in just one copy after division, and is not duplicated until right before...... the next division. Thus, the regions of the chromosome that are the last to be replicated are haploid even in fast-growing bacteria. In contrast to this general rule for bacteria, we found that Lactococcus lactis, a bacterium which has been exploited for thousands of years for the production of fermented...

  2. Physiological Adaptation of the Bacterium Lactococcus lactis in Response to the Production of Human CFTR*

    OpenAIRE

    A. Steen; Wiederhold, E.; T Gandhi; Breitling, R.; D. J. Slotboom

    2010-01-01

    Biochemical and biophysical characterization of CFTR (the cystic fibrosis transmembrane conductance regulator) is thwarted by difficulties to obtain sufficient quantities of correctly folded and functional protein. Here we have produced human CFTR in the prokaryotic expression host Lactococcus lactis. The full-length protein was detected in the membrane of the bacterium, but the yields were too low (< 0.1% of membrane proteins) for in vitro functional and structural characterization, and indu...

  3. Complete Genome Sequence of Lactococcus lactis IO-1, a Lactic Acid Bacterium That Utilizes Xylose and Produces High Levels of l-Lactic Acid

    OpenAIRE

    Kato, Hiroaki; Shiwa, Yuh; Oshima, Kenshiro; Machii, Miki; Araya-Kojima, Tomoko; Zendo, Takeshi; Shimizu-Kadota, Mariko; Hattori, Masahira; Sonomoto, Kenji; Yoshikawa, Hirofumi

    2012-01-01

    We report the complete genome sequence of Lactococcus lactis IO-1 (= JCM7638). It is a nondairy lactic acid bacterium, produces nisin Z, ferments xylose, and produces predominantly l-lactic acid at high xylose concentrations. From ortholog analysis with other five L. lactis strains, IO-1 was identified as L. lactis subsp. lactis.

  4. Deciphering a unique biotin scavenging pathway with redundant genes in the probiotic bacterium Lactococcus lactis.

    Science.gov (United States)

    Zhang, Huimin; Wang, Qingjing; Fisher, Derek J; Cai, Mingzhu; Chakravartty, Vandana; Ye, Huiyan; Li, Ping; Solbiati, Jose O; Feng, Youjun

    2016-01-01

    Biotin protein ligase (BPL) is widespread in the three domains of the life. The paradigm BPL is the Escherichia coli BirA protein, which also functions as a repressor for the biotin biosynthesis pathway. Here we report that Lactococcus lactis possesses two different orthologues of birA (birA1_LL and birA2_LL). Unlike the scenario in E. coli, L. lactis appears to be auxotrophic for biotin in that it lacks a full biotin biosynthesis pathway. In contrast, it retains two biotin transporter-encoding genes (bioY1_LL and bioY2_LL), suggesting the use of a scavenging strategy to obtain biotin from the environment. The in vivo function of the two L. lactis birA genes was judged by their abilities to complement the conditional lethal E. coli birA mutant. Thin-layer chromatography and mass spectroscopy assays demonstrated that these two recombinant BirA proteins catalyze the biotinylation reaction of the acceptor biotin carboxyl carrier protein (BCCP), through the expected biotinoyl-AMP intermediate. Gel shift assays were used to characterize bioY1_LL and BirA1_LL. We also determined the ability to uptake (3)H-biotin by L. lactis. Taken together, our results deciphered a unique biotin scavenging pathway with redundant genes present in the probiotic bacterium L. lactis. PMID:27161258

  5. Physiological Adaptation of the Bacterium Lactococcus lactis in Response to the Production of Human CFTR

    NARCIS (Netherlands)

    Steen, Anton; Wiederhold, Elena; Gandhi, Tejas; Breitling, Rainer; Slotboom, Dirk Jan

    2011-01-01

    Biochemical and biophysical characterization of CFTR (the cystic fibrosis transmembrane conductance regulator) is thwarted by difficulties to obtain sufficient quantities of correctly folded and functional protein. Here we have produced human CFTR in the prokaryotic expression host Lactococcus lacti

  6. Dynamics of pyruvate metabolism in Lactococcus lactis

    DEFF Research Database (Denmark)

    Melchiorsen, Claus Rix; Jensen, Niels B.S.; Christensen, Bjarke;

    2001-01-01

    The pyruvate metabolism in the lactic acid bacterium Lactococcus lactis was studied in anaerobic cultures under transient conditions. During growth of L. lactis in continuous culture at high dilution rate, homolactic product formation was observed, i.e., lactate was produced as the major end prod...

  7. Genome Sequence of Lactococcus lactis subsp. lactis NCDO 2118, a GABA-Producing Strain

    DEFF Research Database (Denmark)

    Oliveira, Letícia C; Saraiva, Tessália D L; Soares, Siomar C;

    2014-01-01

    Lactococcus lactis subsp. lactis NCDO 2118 is a nondairy lactic acid bacterium, a xylose fermenter, and a gamma-aminobutyric acid (GABA) producer isolated from frozen peas. Here, we report the complete genome sequence of L. lactis NCDO 2118, a strain with probiotic potential activity.......Lactococcus lactis subsp. lactis NCDO 2118 is a nondairy lactic acid bacterium, a xylose fermenter, and a gamma-aminobutyric acid (GABA) producer isolated from frozen peas. Here, we report the complete genome sequence of L. lactis NCDO 2118, a strain with probiotic potential activity....

  8. Novel Antibacterial Activity of Lactococcus Lactis Subspecies Lactis Z11 Isolated from Zabady

    OpenAIRE

    Enan, Gamal; Abdel-Shafi, Seham; Ouda, Sahar; Negm, Sally

    2013-01-01

    The purpose of this study was to select and characterize a probiotic bacterium with distinctive antimicrobial activities. In this respect, Lactococcus lactis subspecies lactis Z11 (L. lactis Z11) isolated from Zabady (Arabian yoghurt) inhibited other strains of lactic acid bacteria and some food-born pathogens including Listeria monocytogenes, Bacillus cereus and staphylococcus aureus. The inhibitory activity of cell free supernatant (CFS) of L. lactis Z11 isolated from zabady was lost by pro...

  9. Multidrug transporters and antibiotic resistance in Lactococcus lactis

    NARCIS (Netherlands)

    Poelarends, GJ; Mazurkiewicz, P; Konings, WN

    2002-01-01

    The Gram-positive bacterium Lactococcus lactis produces two distinct multidrug transporters, designated LmrA and LmrP, that both confer resistance to a wide variety of cationic lipophilic cytotoxic compounds as well as to many clinically relevant antibiotics. While LmrP is a proton/drug antiporter t

  10. Glutathione protects Lactococcus lactis against oxidative stress

    NARCIS (Netherlands)

    Li, Y.; Hugenholtz, J.; Abee, T.; Molenaar, D.

    2003-01-01

    Glutathione was found in several dairy Lactococcus lactis strains grown in M17 medium. None of these strains was able to synthesize glutathione. In chemically defined medium, L. lactis subsp. cremoris strain SK11 was able to accumulate up to similar to60 mM glutathione when this compound was added t

  11. Elucidating Flux Regulation of the Fermentation Modes of Lactococcus lactis

    DEFF Research Database (Denmark)

    Chan, Siu Hung Joshua

    The long history of application to the dairy industry has established Lactococcus lactis (L. lactis), the lactic acid bacterium, as one of the most extensively characterized low GC organisms. The relatively simple metabolism of L. lactis has also made it an attractive target for metabolic...... engineering for the production of non-food related chemicals. Moreover, the status of being the first genetically modified organism to deliver immunoproteins alive to human has brought L. lactis considerable fame in biomedical research. Beside the exceptional industrial relevance of L. lactis, it is also an...... amounts of formate, acetate and ethanol are formed, known as mixed-acid fermentation. This shift is termed the mixedacid shift. This type of shift between a low-yield and a high-yield metabolism has drawn a lot of research focus and has similarly been observed in other bacteria, yeast and even tumor cells...

  12. Glutathione protects Lactococcus lactis against oxidative stress

    OpenAIRE

    Li, Y.; Hugenholtz, J.; Abee, T.; Molenaar, D

    2003-01-01

    Glutathione was found in several dairy Lactococcus lactis strains grown in M17 medium. None of these strains was able to synthesize glutathione. In chemically defined medium, L. lactis subsp. cremoris strain SK11 was able to accumulate up to similar to60 mM glutathione when this compound was added to the medium. Stationary-phase cells of strain SK11 grown in chemically defined medium supplemented with glutathione showed significantly increased resistance (up to fivefold increased resistance) ...

  13. Glutathione Protects Lactococcus lactis against Oxidative Stress

    OpenAIRE

    2003-01-01

    Glutathione was found in several dairy Lactococcus lactis strains grown in M17 medium. None of these strains was able to synthesize glutathione. In chemically defined medium, L. lactis subsp. cremoris strain SK11 was able to accumulate up to ∼60 mM glutathione when this compound was added to the medium. Stationary-phase cells of strain SK11 grown in chemically defined medium supplemented with glutathione showed significantly increased resistance (up to fivefold increased resistance) to treatm...

  14. Controlles modulation of folate polyglutamyl tail length by metabolic engineering of Lactococcus lactis

    NARCIS (Netherlands)

    Sybesma, W.F.H.; Born, van den E.; Starrenburg, M.; Mierau, I.; Kleerebezem, M.; Vos, de W.M.; Hugenholtz, J.

    2003-01-01

    The dairy starter bacterium Lactococcus lactis is able to synthesize folate and accumulates >90% of the produced folate intracellularly, predominantly in the polyglutamyl form. Approximately 10% of the produced folate is released into the environment. Overexpression of folC in L. lactis led to an

  15. Functionality of Sortase A in Lactococcus lactis

    NARCIS (Netherlands)

    Dieye, Yakhya; Oxaran, Virginie; Ledue-Clier, Florence; Alkhalaf, Walid; Buist, Girbe; Juillard, Vincent; Lee, Chang Won; Piard, Jean-Christophe

    2010-01-01

    Lactococcus lactis IL1403 harbors a putative sortase A (SrtA) and 11 putative sortase substrates that carry the canonical LPXTG signature of such substrates. We report here on the functionality of SrtA to anchor five LPXTG substrates to the cell wall, thus suggesting that SrtA is the housekeeping so

  16. High efficiency electrotransformation of Lactococcus lactis spp. lactis cells pretreated with lithium acetate and dithiothreitol

    OpenAIRE

    Filioussis George; Avramidis Nicholaos; Papagianni Maria

    2007-01-01

    Abstract Background A goal for the food industry has always been to improve strains of Lactococcus lactis and stabilize beneficial traits. Genetic engineering is used extensively for manipulating this lactic acid bacterium, while electropolation is the most widely used technique for introducing foreign DNA into cells. The efficiency of electrotransformation depends on the level of electropermealization and pretreatment with chemicals which alter cell wall permeability, resulting in improved t...

  17. Gene inactivation in Lactococcus lactis: histidine biosynthesis.

    OpenAIRE

    Delorme, C; Godon, J J; Ehrlich, S D; Renault, P

    1993-01-01

    Lactococcus lactis strains from dairy and nondairy sources were tested for the ability to grow in the absence of histidine. Among 60 dairy strains tested, 56 required histidine, whereas only 1 of 11 nondairy strains had this requirement. Moreover, 10 of the 56 auxotrophic strains were able to grow in the presence of histidinol (Hol+), the immediate histidine precursor. This indicates that adaptation to milk often results in histidine auxotrophy. The histidine operon was detected by Southern h...

  18. Mogućnost primjene bakterije Lactococcus lactis ssp. lactis kao funkcionalne starter kulture

    OpenAIRE

    Frece, Jadranka; Cvrtila, Jelena; Topić, Ivana; Delaš, Frane; Markov, Ksenija

    2014-01-01

    Svrha je ovoga istraživanja bila identificirati i okarakterizirati potencijalne autohtone funkcionalne starter kulture izolirane iz domaće kobasice proizvedene od konjskog mesa. Dominantnu su mikrofloru u uzorcima kobasica činile bakterije mliječne kiseline (BMK), a zatim mikrokoki. Od bakterija mliječne kiseline prevladavale su vrste Lactococcus lactis ssp. lactis i Lactobacillus plantarum. Vrsta Lactococcus lactis ssp. lactis nije uobičajena u fermentiranim kobasicama, pa smo ju okarakteriz...

  19. pSEUDO, a Genetic Integration Standard for Lactococcus lactis

    NARCIS (Netherlands)

    Pinto, Joao P. C.; Zeyniyev, Araz; Karsens, Harma; Trip, Hein; Lolkema, Juke S.; Kuipers, Oscar P.; Kok, Jan

    2011-01-01

    Plasmid pSEUDO and derivatives were used to show that llmg_pseudo_10 in Lactococcus lactis MG1363 and its homologous locus in L. lactis IL1403 are suitable for chromosomal integrations. L. lactis MG1363 and IL1403 nisin-induced controlled expression (NICE) system derivatives (JP9000 and IL9000) and

  20. High efficiency electrotransformation of Lactococcus lactis spp. lactis cells pretreated with lithium acetate and dithiothreitol

    Directory of Open Access Journals (Sweden)

    Filioussis George

    2007-03-01

    Full Text Available Abstract Background A goal for the food industry has always been to improve strains of Lactococcus lactis and stabilize beneficial traits. Genetic engineering is used extensively for manipulating this lactic acid bacterium, while electropolation is the most widely used technique for introducing foreign DNA into cells. The efficiency of electrotransformation depends on the level of electropermealization and pretreatment with chemicals which alter cell wall permeability, resulting in improved transformation efficiencies is rather common practice in bacteria as in yeasts and fungi. In the present study, treatment with lithium acetate (LiAc and dithiothreitol (DTT in various combinations was applied to L. lactis spp. lactis cells of the early-log phase prior to electroporation with plasmid pTRKH3 (a 7.8 kb shuttle vector, suitable for cloning into L. lactis. Two strains of L. lactis spp. lactis were used, L. lactis spp. lactis LM0230 and ATCC 11454. To the best of our knowledge these agents have never been used before with L. lactis or other bacteria. Results Electrotransformation efficiencies of up to 105 transformants per μg DNA have been reported in the literature for L. lactis spp.lactis LM0230. We report here that treatment with LiAc and DDT before electroporation increased transformation efficiency to 225 ± 52.5 × 107 transformants per μg DNA, while with untreated cells or treated with LiAc alone transformation efficiency approximated 1.2 ± 0.5 × 105 transformants per μg DNA. Results of the same trend were obtained with L. lactis ATCC 11454, although transformation efficiency of this strain was significantly lower. No difference was found in the survival rate of pretreated cells after electroporation. Transformation efficiency was found to vary directly with cell density and that of 1010 cells/ml resulted in the highest efficiencies. Following electrotransformation of pretreated cells with LiAc and DDT, pTRKH3 stability was examined

  1. Rewiring Lactococcus lactis for Ethanol Production

    DEFF Research Database (Denmark)

    Solem, Christian; Dehli, Tore Ibsen; Jensen, Peter Ruhdal

    2013-01-01

    to redirect the metabolism of LAB model organism Lactococcus lactis toward ethanol production. Codon-optimized Zymomonas mobilis pyruvate decarboxylase (PDC) was introduced and expressed from synthetic promoters in different strain backgrounds. In the wild-type L. lactis strain MG1363 growing on...... glucose, only small amounts of ethanol were obtained after introducing PDC, probably due to a low native alcohol dehydrogenase activity. When the same strains were grown on maltose, ethanol was the major product and lesser amounts of lactate, formate, and acetate were formed. Inactivating the lactate...... dehydrogenase genes ldhX, ldhB, and ldh and introducing codon-optimized Z. mobilis alcohol dehydrogenase (ADHB) in addition to PDC resulted in high-yield ethanol formation when strains were grown on glucose, with only minor amounts of by-products formed. Finally, a strain with ethanol as the sole observed...

  2. Cold shock of Lactococcus lactis MG1363 are involved in cryoprotection and in the production of cold-induced proteins

    NARCIS (Netherlands)

    Wouters, J.A.; Frenkiel, H.; Vos, de W.M.; Kuipers, O.P.; Abee, T.

    2001-01-01

    Members of the group of 7-kDa cold-shock proteins (CSPs) are the proteins with the highest level of induction upon cold shock in the lactic acid bacterium Lactococcus lactis MG1363. By using double-crossover recombination, two L. lactis strains were generated in which genes encoding CSPs are disrupt

  3. Development, molecular characterization and exploitation of the nisin controlled expression system in Lactococcus lactis.

    NARCIS (Netherlands)

    Ruyter, de P.G.G.A.

    1998-01-01

    Lactic acid bacteria are gram-positive bacteria that are widely used in a variety of dairy fermentation processes. Notably, strains of the lactic acid starter bacterium Lactococcus lactis are of great economic importance because of their world-wide use in cheese making. The characteristic aroma, fla

  4. Relationships between MDR proteins, bacteriocin production and proteolysis in Lactococcus lactis

    NARCIS (Netherlands)

    Gajic, Olivera

    2003-01-01

    The Gram-positive lactic acid bacterium Lactococcus lactis can harbour a wide variety of circular extrachromosomal DNA molecules, so-called plasmids. Many of the traits that make them useful for manufacturing of fermented food products (e.g. bacteriophage resistance, bacteriocin and proteinase produ

  5. Novel antibacterial activity of lactococcus lactis subspecies lactis z11 isolated from zabady.

    Science.gov (United States)

    Enan, Gamal; Abdel-Shafi, Seham; Ouda, Sahar; Negm, Sally

    2013-09-01

    The purpose of this study was to select and characterize a probiotic bacterium with distinctive antimicrobial activities. In this respect, Lactococcus lactis subspecies lactis Z11 (L. lactis Z11) isolated from Zabady (Arabian yoghurt) inhibited other strains of lactic acid bacteria and some food-born pathogens including Listeria monocytogenes, Bacillus cereus and staphylococcus aureus. The inhibitory activity of cell free supernatant (CFS) of L. lactis Z11 isolated from zabady was lost by proteolytic enzymes, heat resistant. Consequently, the active substance(s) of CFS was characterized as a bacteriocin. This bacteriocin has been shown to consist of protein but has no lipidic or glucidic moieties in its active molecule. Its activity was stable in the pH range 2.0 to 7.0 and was not affected by organic solvents. The L. lactis Z11 bacteriocin was produced in CFS throughout the mide to the late exponential phase of growth of the producer organism and maximum bacteriocin production was obtained at initial pH 6.5 at incubation temperature of about 30°C. PMID:24151453

  6. Minimal requirements for exponential growth of Lactococcus lactis

    DEFF Research Database (Denmark)

    Jensen, Peter Ruhdal; Hammer, Karin

    1993-01-01

    A minimal growth medium containing glucose, acetate, vitamins, and eight amino acids allowed for growth of Lactococcus lactis subsp. lactis, with a specific growth rate in batch culture of mu = 0.3 h-1. With 19 amino acids added, the growth rate increased to mu = 0.7 h-1 and the exponential growt...

  7. Autolysis of Lactococcus lactis is influenced by proteolysis

    NARCIS (Netherlands)

    Buist, G; Venema, G; Kok, J.

    1998-01-01

    The autolysin AcmA of Lactococcus lactis was shown to be degraded by the extracellular Lactococcal proteinase PrtP. Autolysis, as evidenced by reduction in optical density of a stationary-phase culture and concomitant release of intracellular proteins, was greatly reduced when L. lactis MG1363 cells

  8. Production and secretion of heterologous proteins by Lactococcus lactis.

    OpenAIRE

    Asseldonk, van, M.

    1994-01-01

    Lactococcus lactis strains have been used for centuries in food fermentation, now appreciated as traditional biotechnology. They have been applied in the cheesemaking process and for the manufacturing of other dairy products. Years of experience with these lactic acid bacteria have led to a profound understanding of the microbiological and technological aspects of L.lactis. Recent progress in the genetics of L. lactis made this organism a suitable candidate for the use in modern biotechnology...

  9. Genes but not genomes reveal bacterial domestication of Lactococcus lactis.

    Directory of Open Access Journals (Sweden)

    Delphine Passerini

    Full Text Available BACKGROUND: The population structure and diversity of Lactococcus lactis subsp. lactis, a major industrial bacterium involved in milk fermentation, was determined at both gene and genome level. Seventy-six lactococcal isolates of various origins were studied by different genotyping methods and thirty-six strains displaying unique macrorestriction fingerprints were analyzed by a new multilocus sequence typing (MLST scheme. This gene-based analysis was compared to genomic characteristics determined by pulsed-field gel electrophoresis (PFGE. METHODOLOGY/PRINCIPAL FINDINGS: The MLST analysis revealed that L. lactis subsp. lactis is essentially clonal with infrequent intra- and intergenic recombination; also, despite its taxonomical classification as a subspecies, it displays a genetic diversity as substantial as that within several other bacterial species. Genome-based analysis revealed a genome size variability of 20%, a value typical of bacteria inhabiting different ecological niches, and that suggests a large pan-genome for this subspecies. However, the genomic characteristics (macrorestriction pattern, genome or chromosome size, plasmid content did not correlate to the MLST-based phylogeny, with strains from the same sequence type (ST differing by up to 230 kb in genome size. CONCLUSION/SIGNIFICANCE: The gene-based phylogeny was not fully consistent with the traditional classification into dairy and non-dairy strains but supported a new classification based on ecological separation between "environmental" strains, the main contributors to the genetic diversity within the subspecies, and "domesticated" strains, subject to recent genetic bottlenecks. Comparison between gene- and genome-based analyses revealed little relationship between core and dispensable genome phylogenies, indicating that clonal diversification and phenotypic variability of the "domesticated" strains essentially arose through substantial genomic flux within the dispensable

  10. Cell Wall Anchoring of the Campylobacter Antigens to Lactococcus lactis.

    Science.gov (United States)

    Kobierecka, Patrycja A; Olech, Barbara; Książek, Monika; Derlatka, Katarzyna; Adamska, Iwona; Majewski, Paweł M; Jagusztyn-Krynicka, Elżbieta K; Wyszyńska, Agnieszka K

    2016-01-01

    Campylobacter jejuni is the most frequent cause of human food-borne gastroenteritis and chicken meat is the main source of infection. Recent studies showed that broiler chicken immunization against Campylobacter should be the most efficient way to lower the number of human infections by this pathogen. Induction of the mucosal immune system after oral antigen administration should provide protective immunity to chickens. In this work we tested the usefulness of Lactococcus lactis, the most extensively studied lactic acid bacterium, as a delivery vector for Campylobacter antigens. First we constructed hybrid protein - CjaA antigen presenting CjaD peptide epitopes on its surface. We showed that specific rabbit anti-rCjaAD serum reacted strongly with both CjaA and CjaD produced by a wild type C. jejuni strain. Next, rCjaAD and CjaA were fused to the C-terminus of the L. lactis YndF containing the LPTXG motif. The genes expressing these proteins were transcribed under control of the L. lactis Usp45 promoter and their products contain the Usp45 signal sequences. This strategy ensures a cell surface location of both analyzed proteins, which was confirmed by immunofluorescence assay. In order to evaluate the impact of antigen location on vaccine prototype efficacy, a L. lactis strain producing cytoplasm-located rCjaAD was also generated. Animal experiments showed a decrease of Campylobacter cecal load in vaccinated birds as compared with the control group and showed that the L. lactis harboring the surface-exposed rCjaAD antigen afforded greater protection than the L. lactis producing cytoplasm-located rCjaAD. To the best of our knowledge, this is the first attempt to employ Lactic Acid Bacteria (LAB) strains as a mucosal delivery vehicle for chicken immunization. Although the observed reduction of chicken colonization by Campylobacter resulting from vaccination was rather moderate, the experiments showed that LAB strains can be considered as an alternative vector to

  11. Regulation of Proteolytic Enzyme Activity in Lactococcus lactis

    OpenAIRE

    Meijer, W.; Marugg, J D; Hugenholtz, J

    1996-01-01

    Two different Lactococcus lactis host strains, L. lactis subsp. lactis MG1363 and L. lactis subsp. cremoris SK1128, both containing plasmid pNZ521, which encodes the extracellular serine proteinase (PrtP) from strain SK110, were used to study the medium and growth-rate-dependent activity of three different enzymes involved in the proteolytic system of lactococci. The activity levels of PrtP and both the intracellular aminopeptidase PepN and the X-prolyl-dipeptidyl aminopeptidase PepXP were st...

  12. Functional Expression of an Orchid Fragrance Gene in Lactococcus lactis

    Directory of Open Access Journals (Sweden)

    Adelene Ai Lian Song

    2012-02-01

    Full Text Available Vanda Mimi Palmer (VMP, an orchid hybrid of Vanda tesselata and Vanda Tan Chay Yan is a highly scented tropical orchid which blooms all year round. Previous studies revealed that VMP produces a variety of isoprenoid volatiles during daylight. Isoprenoids are well known to contribute significantly to the scent of most fragrant plants. They are a large group of secondary metabolites which may possess valuable characteristics such as flavor, fragrance and toxicity and are produced via two pathways, the mevalonate (MVA pathway or/and the 2-C-methyl-D-erythritol-4-phosphate (MEP pathway. In this study, a sesquiterpene synthase gene denoted VMPSTS, previously isolated from a floral cDNA library of VMP was cloned and expressed in Lactococcus lactis to characterize the functionality of the protein. L. lactis, a food grade bacterium which utilizes the mevalonate pathway for isoprenoid production was found to be a suitable host for the characterization of plant terpene synthases. Through recombinant expression of VMPSTS, it was revealed that VMPSTS produced multiple sesquiterpenes and germacrene D dominates its profile.

  13. Expression of PprI from Deinococcus radiodurans Improves Lactic Acid Production and Stress Tolerance in Lactococcus lactis

    OpenAIRE

    Dong, Xiangrong; Tian, Bing; Dai, Shang; Li, Tao; Guo, Linna; Tan, Zhongfang; JIAO, Zhen; Jin, Qingsheng; Wang, Yanping; Hua, Yuejin

    2015-01-01

    PprI is a general switch protein that regulates the expression of certain proteins involved in pathways of cellular resistance in the extremophilic bacterium Deinococcus radiodurans. In this study, we transformed pprI into Lactococcus lactis strain MG1363 using the lactococcal shuttle vector pMG36e and investigated its effects on the tolerance and lactic acid production of L. lactis while under stress. PprI was stably expressed in L. lactis as confirmed by western blot assays. L. lactis expre...

  14. Development, molecular characterization and exploitation of the nisin controlled expression system in Lactococcus lactis.

    OpenAIRE

    Ruyter, de, D.J.

    1998-01-01

    Lactic acid bacteria are gram-positive bacteria that are widely used in a variety of dairy fermentation processes. Notably, strains of the lactic acid starter bacterium Lactococcus lactis are of great economic importance because of their world-wide use in cheese making. The characteristic aroma, flavor and texture of cheese develops during ripening of the cheese curd through the action of numerous enzymes derived from the cheese milk, the coagulant, and the starter and non-starter bacteria. R...

  15. Characterization of the Lactococcus lactis lactose genes and regulation of their expression.

    OpenAIRE

    Rooijen, van, J.

    1993-01-01

    An important trait of the lactic acid bacterium Lactococcus lactis , that is used in industrial dairy fermentations, is the conversion of lactose into lactic acid. The enzymatic steps involved in the breakdown of lactose, that is transported into the cell via a phosphoenolpyruvate-dependent lactose phosphotransferase system (PEP-PTS lac), have been well established (Fig. 1). However, except for the molecular cloning and characterization of the plasmid-located phospho-B-galactosidase gene (Boi...

  16. Functional and Morphological Adaptation to Peptidoglycan Precursor Alteration in Lactococcus lactis*

    OpenAIRE

    Deghorain, Marie; Fontaine, Laetitia; David, Blandine; Mainardi, Jean-Luc; Courtin, Pascal; Daniel, Richard; Errington, Jeff; Sorokin, Alexei; Bolotin, Alexander; Chapot-Chartier, Marie-Pierre; Hallet, Bernard; Hols, Pascal

    2010-01-01

    Cell wall peptidoglycan assembly is a tightly regulated process requiring the combined action of multienzyme complexes. In this study we provide direct evidence showing that substrate transformations occurring at the different stages of this process play a crucial role in the spatial and temporal coordination of the cell wall synthesis machinery. Peptidoglycan substrate alteration was investigated in the Gram-positive bacterium Lactococcus lactis by substituting the peptidoglycan precursor bi...

  17. Expression of the Staphylococcus hyicus Lipase in Lactococcus lactis

    OpenAIRE

    Drouault, Sophie; Corthier, Gerard; Ehrlich, S. Dusko; Renault, Pierre

    2000-01-01

    The extracellular Staphylococcus hyicus lipase was expressed under the control of different promoters in Lactococcus lactis and Bacillus subtilis. Its expression at high and moderate levels is toxic for the former and the latter hosts, respectively. In L. lactis, the lipase was expressed at a high level, up to 30% of the total cellular proteins, under the control of the inducible promoter PnisA. About 80% of the lipase remained associated with the cells. Close to half of this amount remained ...

  18. Use of non-growing Lactococcus lactis cell suspensions for production of volatile metabolites with direct relevance for flavour formation during dairy fermentations

    OpenAIRE

    Bunt, van de, H.G.; Bron, P.A.; Sijtsma, L.; Vos, de, W.M.; Hugenholtz, J

    2014-01-01

    Abstract Background Lactococcus lactis is a lactic acid bacterium that has been used for centuries in the production of a variety of cheeses, as these bacteria rapidly acidify milk and greatly contribute to the flavour of the fermentation end-products. After a short growth phase during cheese ripening L. lactis enters an extended non-growing state whilst s...

  19. Cold Shock Proteins of Lactococcus lactis MG1363 Are Involved in Cryoprotection and in the Production of Cold-Induced Proteins

    NARCIS (Netherlands)

    Wouters, Jeroen A.; Frenkiel, Hélène; Vos, Willem M. de; Kuipers, Oscar P.; Abee, Tjakko

    2001-01-01

    Members of the group of 7-kDa cold-shock proteins (CSPs) are the proteins with the highest level of induction upon cold shock in the lactic acid bacterium Lactococcus lactis MG1363. By using double-crossover recombination, two L. lactis strains were generated in which genes encoding CSPs are disrupt

  20. The riboflavin transporter RibU in Lactococcus lactis : Molecular characterization of gene expression and the transport mechanism

    NARCIS (Netherlands)

    Burgess, CM; Slotboom, DJ; Geertsma, ER; Duurkens, Hinderika; Poolman, B; van Sinderen, D

    2006-01-01

    This study describes the characterization of the riboflavin transport protein RibU in the lactic acid bacterium Lactococcus lactis subsp. cremoris NZ9000. RibU is predicted to contain five membrane-spanning segments and is a member of a novel transport protein family, not described in the Transport

  1. Versatile vector suite for the extracytoplasmic production and purification of heterologous His-tagged proteins in Lactococcus lactis

    NARCIS (Netherlands)

    Neef, Jolanda; Milder, Fin J.; Koedijk, Danny G. A. M.; Klaassens, Marindy; Heezius, Erik C.; van Strijp, Jos A. G.; Otto, Andreas; Becher, Doerte; van Dijl, Jan Maarten; Buist, Girbe

    2015-01-01

    Recent studies have shown that the Gram-positive bacterium Lactococcus lactis can be exploited for the expression of heterologous proteins; however, a versatile set of vectors suitable for inducible extracellular protein production and subsequent purification of the expressed proteins by immobilized

  2. Tulum Peynirlerinden izole Edilen Lactococcus lactis subsp. lactis YBML9 ve

    Directory of Open Access Journals (Sweden)

    Yasin TUNCER

    2009-04-01

    Full Text Available Bu çalısmanın amacı tulum peynirlerinden izole edilen Lactococcus lactis suslarının fenotipik tanısı ve bu suslar tarafından üretilen bakteriyosinlerin kısmi karakterizasyonlarıdır. Bu amaçla Türkiye'nin sekiz farklı ilinden (Ankara, Antalya, Burdur, Denizli, Erzincan, Isparta, İstanbul ve İzmir yöresel pazarlardan toplanan 60 adet tulum peyniri örneginden 40 adet Lactococcus lactis susu (31 adet L. lactis subsp. lactis ve 9 adet L. lactis subsp. cremoris izole edildi. 40 adet L. lactis susu içerisinden, 2 adet L. lactis subsp. lactis (YBML9 ve YBML21 susu bakteriyosin üretme yeteneginde bulundu. L. lactis subsp. lactis YBML9 ve YBML21 susları tarafından üretilen bakteriyosinler, farklı enzim, pH ve sıcaklık uygulamaları sonucu; sırasıyla nisin ve laktisin 481 olarak tanımlandı.

  3. Stability of Integrated Plasmids in the Chromosome of Lactococcus lactis

    NARCIS (Netherlands)

    Leenhouts, Kees J.; Kok, Jan; Venema, Gerhardus

    1990-01-01

    Derivatives of plasmids pBR322, pUB110, pSC101, and pTB19, all containing an identical fragment of lactococcal chromosomal DNA, were integrated via a Campbell-like mechanism into the same chromosomal site of Lactococcus lactis MG1363, and the transformants were analyzed for the stability of the inte

  4. Nisin-Producing Lactococcus lactis Strains Isolated from Human Milk

    OpenAIRE

    Beasley, Shea S.; Saris, Per E. J.

    2004-01-01

    Characterization by partial 16S rRNA gene sequencing, ribotyping, and green fluorescent protein-based nisin bioassay revealed that 6 of 20 human milk samples contained nisin-producing Lactococcus lactis bacteria. This suggests that the history of humans consuming nisin is older than the tradition of consuming fermented milk products.

  5. Nucleotide metabolism in Lactococcus lactis: Salvage pathways of exogenous pyrimidines

    DEFF Research Database (Denmark)

    Martinussen, Jan; Andersen, Paal Skytt; Hammer, Karin

    1994-01-01

    By measuring enzyme activities in crude extracts and studying the effect of toxic analogs (5-fluoropyrimidines) on cell growth, the metabolism of pyrimidines in Lactococcus lactis was analyzed. Pathways by which uracil, uridine, deoxyuridine, cytidine, and deoxycytidine are metabolized in L. lact...

  6. Structure-function analysis of multidrug transporters in Lactococcus lactis

    NARCIS (Netherlands)

    van Veen, HW; Putman, M; Margolles, A; Sakamoto, K; Konings, WN

    1999-01-01

    The active extrusion of cytotoxic compounds from the cell by multidrug transporters is one of the major causes of failure of chemotherapeutic treatment of tumor cells and of infections by pathogenic microorganisms. A multidrug transporter in Lactococcus lactis, LmrA, is a member of the ATP-binding c

  7. Production and secretion of heterologous proteins by Lactococcus lactis.

    NARCIS (Netherlands)

    Asseldonk, van M.

    1994-01-01

    Lactococcus lactis strains have been used for centuries in food fermentation, now appreciated as traditional biotechnology. They have been applied in the cheesemaking process and for the manufacturing of other dairy products. Years of experience with these lactic acid bacteria have led to a profound

  8. Microbiota of Minas cheese as influenced by the nisin producer Lactococcus lactis subsp. lactis GLc05.

    Science.gov (United States)

    Perin, Luana Martins; Dal Bello, Barbara; Belviso, Simona; Zeppa, Giuseppe; de Carvalho, Antônio Fernandes; Cocolin, Luca; Nero, Luís Augusto

    2015-12-01

    Minas cheese is a popular dairy product in Brazil that is traditionally produced using raw or pasteurized cow milk. This study proposed an alternative production of Minas cheese using raw goat milk added of a nisin producer Lactococcus lactis subsp. lactis GLc05. An in situ investigation was carried on to evaluate the interactions between the L. lactis subsp. lactis GLc05 and the autochthonous microbiota of a Minas cheese during the ripening; production of biogenic amines (BAs) was assessed as a safety aspect. Minas cheese was produced in two treatments (A, by adding L. lactis subsp. lactis GLc05, and B, without adding this strain), in three independent repetitions (R1, R2, and R3). Culture dependent (direct plating) and independent (rep-PCR and PCR-DGGE) methods were employed to characterize the microbiota and to assess the possible interferences caused by L. lactis subsp. lactis GLc05. BA amounts were measured using HPLC. A significant decrease in coagulase-positive cocci was observed in the cheeses produced by adding L. lactis subsp. lactis GLc05 (cheese A). The rep-PCR and PCR-DGGE highlighted the differences in the microbiota of both cheeses, separating them into two different clusters. Lactococcus sp. was found as the main microorganism in both cheeses, and the microbiota of cheese A presented a higher number of species. High concentrations of tyramine were found in both cheeses and, at specific ripening times, the BA amounts in cheese B were significantly higher than in cheese A (p<0.05). The interaction of nisin producer L. lactis subsp. lactis GLc05 was demonstrated in situ, by demonstration of its influence in the complex microbiota naturally present in a raw goat milk cheese and by controlling the growth of coagulase-positive cocci. L. lactis subsp. lactis GLc05 influenced also the production of BA determining that their amounts in the cheeses were maintained at acceptable levels for human consumption. PMID:26310130

  9. Bacteriocinogenic Lactococcus lactis subsp. lactis DF04Mi isolated from goat milk: Characterization of the bacteriocin

    OpenAIRE

    Furtado, Danielle N.; Todorov, Svetoslav D.; Mariza Landgraf; Maria T. Destro; Franco, Bernadette D.G.M.

    2015-01-01

    Lactic acid bacteria capable of producing bacteriocins and presenting probiotic potential open innovative technological applications in the dairy industry. In this study, a bacteriocinogenic strain (Lactococcus lactis subsp. lactis DF4Mi) was isolated from goat milk, and studied for its antimicrobial activity. The bacteriocin presented a broad spectrum of activity, was sensitive to proteolytic enzymes, resistant to heat and pH extremes, and not affected by the presence of SDS, Tween 20, Tween...

  10. Control of Brochothrix thermosphacta in pork meat using Lactococcus lactis subsp. lactis I23 isolated from beef

    Directory of Open Access Journals (Sweden)

    Olusegun A Olaoye

    2015-06-01

    Full Text Available This study evaluated the antimicrobial activities of two lactic acid bacteria (LAB Lactococcus lactis subsp. lactis I23 and L. lactis subsp. hordinae E91 against Brochothrix thermosphacta in pork during storage at ambient temperature (30oC over 7 days. Both the LAB strains and spoilage organism were inoculated on fresh pork samples at 1x106cfu/g. About 3 log reduction in the spoilage organism was obtained in LAB treated samples after 48 h of storage. The spoilage organism was confirmed to be sensitive to the bacteriocin nisin produced by Lactococcus lactis subsp. lactis I23. There were reductions in the counts of Salmonella typhimurium, Listeria monocytogenes, Enterobacteriaceae and Staphylococcus in the treated samples. Conclusively, growth of B. thermosphacta could be effectively controlled by nisin producing Lactococcus lactis subsp. lactis I23 in fresh pork during storage, thereby enhancing shelf life of the product.

  11. Taxonomy, physiology and growth of Lactococcus lactis: a review

    Directory of Open Access Journals (Sweden)

    Dubravka Samaržija

    2001-01-01

    Full Text Available Lactococcus lactis species is one of the most important groups of lactic acid bacteria that are used in the dairy industry. The major functions of this species in dairy fermentation are the production of lactic acid from lactose, hydrolysis of casein and citric acid fermentation. Thus their metabolic end products and enzymes directly or indirectly have significant influence in determining the texture and flavour of the final products. In recent years, genetics and physiological properties of lactococci have considerable changed. Therefore, both for basic research and for application purposes in this paper the general view of the new taxonomic classification of Lactococcus lactis, the role of their plasmids and the physiology and nutritional requirements during growth are discussed.

  12. Taxonomy, physiology and growth of Lactococcus lactis: a review

    OpenAIRE

    Dubravka Samaržija; Neven Antunac; Jasmina Lukač Havranek

    2001-01-01

    Lactococcus lactis species is one of the most important groups of lactic acid bacteria that are used in the dairy industry. The major functions of this species in dairy fermentation are the production of lactic acid from lactose, hydrolysis of casein and citric acid fermentation. Thus their metabolic end products and enzymes directly or indirectly have significant influence in determining the texture and flavour of the final products. In recent years, genetics and physiological properties of ...

  13. Relationship between Glycolysis and Exopolysaccharide Biosynthesis in Lactococcus lactis

    OpenAIRE

    Ramos, Ana; Boels, Ingeborg C.; de Vos, Willem M; Santos, Helena

    2001-01-01

    The relationships between glucose metabolism and exopolysaccharide (EPS) production in a Lactococcus lactis strain containing the EPS gene cluster (Eps+) and in nonproducer strain MG5267 (Eps−) were characterized. The concentrations of relevant phosphorylated intermediates in EPS and cell wall biosynthetic pathways or glycolysis were determined by 31P nuclear magnetic resonance. The concentrations of two EPS precursors, UDP-glucose and UDP-galactose, were significantly lower in the Eps+ strai...

  14. Molecular Physiology of Sugar Catabolism in Lactococcus lactis IL1403

    OpenAIRE

    Even, Sergine; Lindley, Nic D.; Cocaign-Bousquet, Muriel

    2001-01-01

    The metabolic characteristics of Lactococcus lactis IL1403 were examined on two different growth media with respect to the physiological response to two sugars, glucose and galactose. Analysis of specific metabolic rates indicated that despite significant variations in the rates of both growth and sugar consumption, homolactic fermentation was maintained for all cultures due to the low concentration of either pyruvate-formate lyase or alcohol dehydrogenase. When the ionophore monensin was add...

  15. Relationship between glycolysis and exopolysaccharide biosynhesis in Lactococcus lactis

    OpenAIRE

    Ramos, A.; Boels, I. C.; Vos; Santos, H.

    2001-01-01

    The relationships between glucose metabolism and exopolysaccharide (EPS) production in a Lactococcus lactis strain containing the EPS gene cluster (Eps ) and in nonproducer strain MG5267 (Eps) were characterized. The concentrations of relevant phosphorylated intermediates in EPS and cell wall biosynthetic pathways or glycolysis were determined by 31P nuclear magnetic resonance. The concentrations of two EPS precursors, UDP-glucose and UDP-galactose, were significantly lower in the Eps strain ...

  16. Draft Genome Sequence of Lactococcus lactis subsp. lactis bv. diacetylactis CRL264, a Citrate-Fermenting Strain

    OpenAIRE

    Zuljan, Federico; Espariz, Martín; Blancato, Victor S.; Esteban, Luis; Alarcón, Sergio; Magni, Christian

    2016-01-01

    We report the draft genome sequence of Lactococcus lactis subsp. lactis bv. diacetylactis CRL264, a natural strain isolated from artisanal cheese from northwest Argentina. L. lactis subsp. lactis bv. diacetylactis is one of the most important microorganisms used as starter culture around the world. The CRL264 strain constitutes a model microorganism in the studies on the generation of aroma compounds (diacetyl, acetoin, and 2,3-butanediol) by lactic acid bacteria. Our genome analysis shows si...

  17. Over-expressed CmbT multidrug resistance transporter improves the fitness of Lactococcus lactis

    Directory of Open Access Journals (Sweden)

    Filipić Brankica

    2013-01-01

    Full Text Available The influence of the over-expression of CmbT multidrug resistance transporter on the growth rate of Lactococcus lactis NZ9000 was studied. L. lactis is a lactic acid bacteria (LAB widely used as a starter culture in dairy industry. Recently characterized CmbT MDR transporter in L. lactis confers resistance to a wide variety of toxic compounds as well as to some clinically relevant antibiotics. In this study, the cmbT gene was over-expressed in the strain L. lactis NZ9000 in the presence of nisin inducer. Over-expression of the cmbT gene in L. lactis NZ9000 was followed by RT-PCR. The obtained results showed that the cmbT gene was successfully over-expressed by addition of sub-inhibitory amounts of nisin. Growth curves of L. lactis NZ9000/pCT50 over-expressing the cmbT gene and L. lactis NZ9000 control strain were followed in the rich medium as well as in the chemically defined medium in the presence solely of methionine (0.084 mM or mix of methionine and cysteine (8.4 mM and 8.2 mM, respectively. Resulting doubling times revealed that L. lactis NZ9000/pCT50 had higher growth rate comparing to the control strain. This could be a consequence of the CmbT efflux activity, which improves the fitness of the host bacterium through the elimination of toxic compounds from the cell.

  18. Expanding the molecular toolbox for Lactococcus lactis: construction of an inducible thioredoxin gene fusion expression system

    LENUS (Irish Health Repository)

    Douillard, Francois P

    2011-08-09

    Abstract Background The development of the Nisin Inducible Controlled Expression (NICE) system in the food-grade bacterium Lactococcus lactis subsp. cremoris represents a cornerstone in the use of Gram-positive bacterial expression systems for biotechnological purposes. However, proteins that are subjected to such over-expression in L. lactis may suffer from improper folding, inclusion body formation and\\/or protein degradation, thereby significantly reducing the yield of soluble target protein. Although such drawbacks are not specific to L. lactis, no molecular tools have been developed to prevent or circumvent these recurrent problems of protein expression in L. lactis. Results Mimicking thioredoxin gene fusion systems available for E. coli, two nisin-inducible expression vectors were constructed to over-produce various proteins in L. lactis as thioredoxin fusion proteins. In this study, we demonstrate that our novel L. lactis fusion partner expression vectors allow high-level expression of soluble heterologous proteins Tuc2009 ORF40, Bbr_0140 and Tuc2009 BppU\\/BppL that were previously insoluble or not expressed using existing L. lactis expression vectors. Over-expressed proteins were subsequently purified by Ni-TED affinity chromatography. Intact heterologous proteins were detected by immunoblotting analyses. We also show that the thioredoxin moiety of the purified fusion protein was specifically and efficiently cleaved off by enterokinase treatment. Conclusions This study is the first description of a thioredoxin gene fusion expression system, purposely developed to circumvent problems associated with protein over-expression in L. lactis. It was shown to prevent protein insolubility and degradation, allowing sufficient production of soluble proteins for further structural and functional characterization.

  19. Genome Sequence of a Lactococcus lactis Strain Isolated from Salmonid Intestinal Microbiota.

    Science.gov (United States)

    Opazo, Rafael; Gajardo, Felipe; Ruiz, Mauricio; Romero, Jaime

    2016-01-01

    Lactococcus lactis is a common inhabitant of the intestinal microbiota of salmonids, especially those in aquaculture systems. Here, we present a genome sequence of a Lactococcus lactis strain isolated from the intestinal contents of rainbow trout reared in Chile. PMID:27563049

  20. Characterization of bacteriocins produced by Lactococcus lactis strains Caracterização de bacteriocinas produzidas por linhagens de Lactococcus lactis

    Directory of Open Access Journals (Sweden)

    Izildinha Moreno

    2000-09-01

    Full Text Available Bacteriocins produced by fifteen strains of Lactococcus lactis (14 L. lactis subsp. lactis and one L. lactis subsp. cremoris were heat resistant, sensitive to several proteolytic enzymes and active over a wide range of pH. Their resistance to the heating was greatly influenced by the pH. Only the strain L. lactis subsp. lactis ITAL 383 produced a bacteriocin with a wide activity spectrum, similar to nisin of L. lactis subsp. lactis ATCC 11454. This bacteriocin inhibited closely related species and other Gram-positive microorganisms including Listeria monocytogenes and Staphylococcus aureus, but it was not active against the Gram-negative bacteria tested. The identification of partially purified antimicrobial compounds by SDS-PAGE showed that bacteriocin produced by strain ITAL 383 had the same molecular weight of nisin produced by L. lactis subsp. lactis ATCC 11454.Bacteriocinas resistentes ao aquecimento produzidas por quinze linhagens de Lactococcus lactis (14 L. lactis subsp. lactis e 1 L. lactis subsp. cremoris foram sensíveis à enzimas proteolíticas e ativas em uma ampla faixa de pH. A resistência dessas bacteriocinas ao aquecimento foi fortemente influenciada pelo pH do meio. Somente a linhagem L. lactis subsp. lactis ITAL 383 produziu uma bacteriocina com um amplo espectro de atividade, semelhante ao da nisina de L. lactis subsp. lactis ATCC 11454. Esta bacteriocina inibiu as espécies relacionadas e outros microorganismos gram-positivos, inclusive Listeria monocytogenes e Staphylococcus aureus, mas não as bactérias Gram-negativas examinadas. A identificação do composto antimicrobiano parcialmente purificado por SDS-PAGE revelou um peso molecular similar entre a bacteriocina ITAL 383 e a nisina de L. lactis subsp lactis ATCC 11454.

  1. Bacteriocinogenic Lactococcus lactis subsp. lactis DF04Mi isolated from goat milk: characterization of the bacteriocin.

    Science.gov (United States)

    Furtado, Danielle N; Todorov, Svetoslav D; Landgraf, Mariza; Destro, Maria T; Franco, Bernadette D G M

    2014-01-01

    Lactic acid bacteria capable of producing bacteriocins and presenting probiotic potential open innovative technological applications in the dairy industry. In this study, a bacteriocinogenic strain (Lactococcus lactis subsp. lactis DF4Mi) was isolated from goat milk, and studied for its antimicrobial activity. The bacteriocin presented a broad spectrum of activity, was sensitive to proteolytic enzymes, resistant to heat and pH extremes, and not affected by the presence of SDS, Tween 20, Tween 80, EDTA or NaCl. Bacteriocin production was dependent on the components of the culture media, especially nitrogen source and salts. When tested by PCR, the bacteriocin gene presented 100% homology to nisin Z gene. These properties indicate that this L. lactis subsp. lactis DF4Mi can be used for enhancement of dairy foods safety and quality. PMID:25763065

  2. Bacteriocinogenic Lactococcus lactis subsp. lactis DF04Mi isolated from goat milk: characterization of the bacteriocin

    Directory of Open Access Journals (Sweden)

    Danielle N. Furtado

    2014-12-01

    Full Text Available Lactic acid bacteria capable of producing bacteriocins and presenting probiotic potential open innovative technological applications in the dairy industry. In this study, a bacteriocinogenic strain (Lactococcus lactis subsp. lactis DF4Mi was isolated from goat milk, and studied for its antimicrobial activity. The bacteriocin presented a broad spectrum of activity, was sensitive to proteolytic enzymes, resistant to heat and pH extremes, and not affected by the presence of SDS, Tween 20, Tween 80, EDTA or NaCl. Bacteriocin production was dependent on the components of the culture media, especially nitrogen source and salts. When tested by PCR, the bacteriocin gene presented 100% homology to nisin Z gene. These properties indicate that this L. lactis subsp. lactis DF4Mi can be used for enhancement of dairy foods safety and quality.

  3. Production of recombinant peanut allergen Ara h 2 using Lactococcus lactis

    DEFF Research Database (Denmark)

    Glenting, J.; Poulsen, Lars K.; Kato, K.; Madsen, S.M.; Frøkiær, Hanne; Wendt, C.; Sorensen, H.W.

    2007-01-01

    Background: Natural allergen sources can supply large quantities of authentic allergen mixtures for use as immunotherapeutics. However, such extracts are complex, difficult to define, vary from batch to batch, which may lead to unpredictable efficacy and/ or unacceptable levels of side effects. The...... use of recombinant expression systems for allergen production can alleviate some of these issues. Several allergens have been tested in high- level expression systems and in most cases show immunereactivity comparable to their natural counterparts. The gram positive lactic acid bacterium Lactococcus...... lactis is an attractive microorganism for use in the production of protein therapeutics. L. lactis is considered food grade, free of endotoxins, and is able to secrete the heterologous product together with few other native proteins. Hypersensitivity to peanut represents a serious allergic problem. Some...

  4. Intranasal Immunization with Recombinant Lactococcus lactis Secreting Murine Interleukin-12 Enhances Antigen-Specific Th1 Cytokine Production

    OpenAIRE

    Bermudez Humaran, Luis; Langella, Philippe; Cortes-Perez, Naima; Gruss, Alexandra; Tamez-Guerra, Reyes S; Oliveira, Sergio C.; Saucedo-Cardenas, Odila; Montes de Oca-Luna, Roberto; Le Loir, Yves

    2003-01-01

    Interleukin-12 (IL-12), a heterodimeric cytokine, plays an important role in cellular immunity to several bacterial, viral, and parasitic infections and has adjuvant activity when it is codelivered with DNA vaccines. IL-12 has also been used with success in cancer immunotherapy treatments. However, systemic IL-12 therapy has been limited by high levels of toxicity. We describe here inducible expression and secretion of IL-12 in the food-grade lactic acid bacterium Lactococcus lactis. IL-12 wa...

  5. Heterologous expression of Brucella abortus GroEL heat-shock protein in Lactococcus lactis

    Directory of Open Access Journals (Sweden)

    Langella Philippe

    2006-03-01

    Full Text Available Abstract Background Brucella abortus is a facultative intracellular pathogen that mainly infects cattle and humans. Current vaccines rely on live attenuated strains of B. abortus, which can revert to their pathogenic status and thus are not totally safe for use in humans. Therefore, the development of mucosal live vaccines using the food-grade lactic acid bacterium, Lactococcus lactis, as an antigen delivery vector, is an attractive alternative and a safer vaccination strategy against B. abortus. Here, we report the construction of L. lactis strains genetically modified to produce B. abortus GroEL heat-shock protein, a candidate antigen, in two cellular locations, intracellular or secreted. Results Only the secreted form of GroEL was stably produced in L. lactis, suggesting a detrimental effect of GroEL protein when intracellularly produced in this bacterium. Only trace amounts of mature GroEL were detected in the supernatant fraction of induced lactococcal cultures, and the GroEL precursor remained stacked in the cell fraction. Attempts to raise the secretion yields were made, but even when GroEL was fused to a synthetic propeptide, secretion of this antigen was not improved. Conclusion We found that L. lactis is able to produce, and to secrete, a stable form of GroEL into the extracellular medium. Despite the low secretion efficiency of GroEL, which suggest that this antigen interacts with the cell envelope of L. lactis, secretion seems to be the best way to achieve both production and protein yields, regardless of cellular location. The L. lactis strain secreting GroEL has potential for in vivo immunization.

  6. Mucosal Delivery of Murine Interleukin-2 (IL-2) and IL-6 by Recombinant Strains of Lactococcus lactis Coexpressing Antigen and Cytokine

    OpenAIRE

    Steidler, Lothar; Robinson, K.; Chamberlain, L.; SCHOFIELD, KM; Remaut, Erik; LE PAGE, RWF; Wells, JM

    1998-01-01

    Lactococcus lactis is a nonpathogenic and noncolonizing bacterium which is being developed as a vaccine delivery vehicle for immunization by mucosal routes. To determine whether lactococci can also deliver cytokines to the immune system, we have constructed novel constitutive expression strains of L. lactis which accumulate a test antigen, tetanus toxin fragment C (TTFC), within the cytoplasmic compartment and also secrete either murine interleukin-2 (IL-2) or IL-6. When mice were immunized i...

  7. Heterologous Gene Expression in Lactococcus lactis subsp. lactis : Synthesis, Secretion, and Processing of the Bacillus subtilis Neutral Protease

    NARCIS (Netherlands)

    Guchte, Maarten van de; Kodde, Jan; Vossen, Jos M.B.M. van der; Kok, Jan; Venema, Gerard

    1990-01-01

    The Bacillus subtilis nprE gene lacking its own promoter sequence was inserted in the lactococcal expression vector pMG36e. Upon introduction of the recombinant plasmid into Lactococcus lactis subsp. lactis strain MG1363, neutral protease activity could be visualized by the appearance of large clear

  8. Heterologous Expression and Characterization of an N-Acetyl-beta-D-hexosaminidase from Lactococcus lactis ssp. lactis IL1403

    Czech Academy of Sciences Publication Activity Database

    Nguyen, A. H.; Nguyen, T.-H.; Křen, Vladimír; Eijsink, V. G. H.; Haltrich, D.; Peterbauer, C.

    2012-01-01

    Roč. 60, č. 12 (2012), s. 3275-3281. ISSN 0021-8561 R&D Projects: GA ČR(CZ) GAP207/11/0629 Keywords : N-acetyl-beta-D-hexosaminidase * Lactococcus lactis ssp lactis IL1403 * pNP-GlcNAc Subject RIV: CE - Biochemistry Impact factor: 2.906, year: 2012

  9. Draft Genome Sequence of Lactococcus lactis subsp. lactis bv. diacetylactis CRL264, a Citrate-Fermenting Strain.

    Science.gov (United States)

    Zuljan, Federico; Espariz, Martín; Blancato, Victor S; Esteban, Luis; Alarcón, Sergio; Magni, Christian

    2016-01-01

    We report the draft genome sequence of Lactococcus lactis subsp. lactis bv. diacetylactis CRL264, a natural strain isolated from artisanal cheese from northwest Argentina. L. lactis subsp. lactis bv. diacetylactis is one of the most important microorganisms used as starter culture around the world. The CRL264 strain constitutes a model microorganism in the studies on the generation of aroma compounds (diacetyl, acetoin, and 2,3-butanediol) by lactic acid bacteria. Our genome analysis shows similar genetic organization to other available genomes of L. lactis bv. diacetylactis strains. PMID:26847906

  10. Draft Genome Sequence of Lactococcus lactis subsp. lactis bv. diacetylactis CRL264, a Citrate-Fermenting Strain

    Science.gov (United States)

    Zuljan, Federico; Espariz, Martín; Blancato, Victor S.; Esteban, Luis; Alarcón, Sergio

    2016-01-01

    We report the draft genome sequence of Lactococcus lactis subsp. lactis bv. diacetylactis CRL264, a natural strain isolated from artisanal cheese from northwest Argentina. L. lactis subsp. lactis bv. diacetylactis is one of the most important microorganisms used as starter culture around the world. The CRL264 strain constitutes a model microorganism in the studies on the generation of aroma compounds (diacetyl, acetoin, and 2,3-butanediol) by lactic acid bacteria. Our genome analysis shows similar genetic organization to other available genomes of L. lactis bv. diacetylactis strains. PMID:26847906

  11. Bacteriocinogenic Lactococcus lactis subsp. lactis DF04Mi isolated from goat milk: Evaluation of the probiotic potential

    OpenAIRE

    Furtado, Danielle N.; Todorov, Svetoslav D.; Mariza Landgraf; Maria T. Destro; Franco, Bernadette D.G.M.

    2014-01-01

    Lactic acid bacteria capable of producing bacteriocins and presenting probiotic potential open innovative technological applications in the dairy industry. In this study, a bacteriocinogenic strain (Lactococcus lactis subsp. lactis DF4Mi) was isolated from goat milk, and studied for its probiotic potential. Lc. lactis DF4Mi was resistant to acidic pH and oxbile, presented co-aggregation with Listeria monocytogenes, and was not affected by several drugs from different generic groups, being sen...

  12. Modeling Lactococcus lactis using a genome-scale flux model

    Directory of Open Access Journals (Sweden)

    Nielsen Jens

    2005-06-01

    Full Text Available Abstract Background Genome-scale flux models are useful tools to represent and analyze microbial metabolism. In this work we reconstructed the metabolic network of the lactic acid bacteria Lactococcus lactis and developed a genome-scale flux model able to simulate and analyze network capabilities and whole-cell function under aerobic and anaerobic continuous cultures. Flux balance analysis (FBA and minimization of metabolic adjustment (MOMA were used as modeling frameworks. Results The metabolic network was reconstructed using the annotated genome sequence from L. lactis ssp. lactis IL1403 together with physiological and biochemical information. The established network comprised a total of 621 reactions and 509 metabolites, representing the overall metabolism of L. lactis. Experimental data reported in the literature was used to fit the model to phenotypic observations. Regulatory constraints had to be included to simulate certain metabolic features, such as the shift from homo to heterolactic fermentation. A minimal medium for in silico growth was identified, indicating the requirement of four amino acids in addition to a sugar. Remarkably, de novo biosynthesis of four other amino acids was observed even when all amino acids were supplied, which is in good agreement with experimental observations. Additionally, enhanced metabolic engineering strategies for improved diacetyl producing strains were designed. Conclusion The L. lactis metabolic network can now be used for a better understanding of lactococcal metabolic capabilities and potential, for the design of enhanced metabolic engineering strategies and for integration with other types of 'omic' data, to assist in finding new information on cellular organization and function.

  13. Construction of a new shuttle vector for DNA delivery into mammalian cells using non-invasive Lactococcus lactis.

    Science.gov (United States)

    Yagnik, Bhrugu; Padh, Harish; Desai, Priti

    2016-04-01

    Use of food grade Lactococcus lactis (L. lactis) is fast emerging as a safe alternative for delivery of DNA vaccine. To attain efficient DNA delivery, L. lactis, a non-invasive bacterium is converted to invasive strain either by expressing proteins like Internalin A (InlA) or Fibronectin binding protein A (FnBPA) or through chemical treatments. However the safety status of invasive L. lactis is questionable. In the present report, we have shown that non-invasive L. lactis efficiently delivered the newly constructed reporter plasmid pPERDBY to mammalian cells without any chemical enhancers. The salient features of the vector are; I) Ability to replicate in two different hosts; Escherichia coli (E. coli) and Lactic Acid Bacteria (LAB), II) One of the smallest reporter plasmid for DNA vaccine, III) Enhanced Green Fluorescence Protein (EGFP) linked to Multiple Cloning Site (MCS), IV) Immunostimulatory CpG motifs functioning as an adjuvant. Expression of EGFP in pPERDBY transfected CHO-K1 and Caco-2 cells demonstrates its functionality. Non-invasive r-L. lactis was found efficient in delivering pPERDBY to Caco-2 cells. The in vitro data presented in this article supports the hypothesis that in the absence of invasive proteins or relevant chemical treatment, L. lactis was found efficient in delivering DNA to mammalian cells. PMID:26655884

  14. Engineering of carbon distribution between glycolysis and sugar nucleobiosynthesis in Lactococcus lactis

    NARCIS (Netherlands)

    Boels, I.C.; Kleerebezem, M.; Vos, de W.M.

    2003-01-01

    We describe the effects of modulating the activities of glucokinase, phosphofructokinase, and phosphoglucomutase on the branching point between sugar degradation and the biosynthesis of sugar nucleotides involved in the production of exopolysaccharide biosynthesis by Lactococcus lactis. This was rea

  15. Mobile CRISPR/Cas-mediated bacteriophage resistance in Lactococcus lactis.

    Directory of Open Access Journals (Sweden)

    Anne M Millen

    Full Text Available Lactococcus lactis is a biotechnological workhorse for food fermentations and potentially therapeutic products and is therefore widely consumed by humans. It is predominantly used as a starter microbe for fermented dairy products, and specialized strains have adapted from a plant environment through reductive evolution and horizontal gene transfer as evidenced by the association of adventitious traits with mobile elements. Specifically, L. lactis has armed itself with a myriad of plasmid-encoded bacteriophage defensive systems to protect against viral predation. This known arsenal had not included CRISPR/Cas (clustered regularly interspaced short palindromic repeats/CRISPR-associated proteins, which forms a remarkable microbial immunity system against invading DNA. Although CRISPR/Cas systems are common in the genomes of closely related lactic acid bacteria (LAB, none was identified within the eight published lactococcal genomes. Furthermore, a PCR-based search of the common LAB CRISPR/Cas systems (Types I and II in 383 industrial L. lactis strains proved unsuccessful. Here we describe a novel, Type III, self-transmissible, plasmid-encoded, phage-interfering CRISPR/Cas discovered in L. lactis. The native CRISPR spacers confer resistance based on sequence identity to corresponding lactococcal phage. The interference is directed at phages problematic to the dairy industry, indicative of a responsive system. Moreover, targeting could be modified by engineering the spacer content. The 62.8-kb plasmid was shown to be conjugally transferrable to various strains. Its mobility should facilitate dissemination within microbial communities and provide a readily applicable system to naturally introduce CRISPR/Cas to industrially relevant strains for enhanced phage resistance and prevention against acquisition of undesirable genes.

  16. Bacteriocinogenic Lactococcus lactis subsp: lactis DF04Mi isolated from goat milk: Evaluation of the probiotic potential

    Directory of Open Access Journals (Sweden)

    Danielle N. Furtado

    2014-09-01

    Full Text Available Lactic acid bacteria capable of producing bacteriocins and presenting probiotic potential open innovative technological applications in the dairy industry. In this study, a bacteriocinogenic strain (Lactococcus lactis subsp. lactis DF4Mi was isolated from goat milk, and studied for its probiotic potential. Lc. lactis DF4Mi was resistant to acidic pH and oxbile, presented co-aggregation with Listeria monocytogenes, and was not affected by several drugs from different generic groups, being sensitive to most tested antibiotics. These properties indicate that this Lc. lactis strain can be used for enhancement of dairy foods safety and quality, in combination with potential probiotic properties.

  17. Bacteriocinogenic Lactococcus lactis subsp. lactis DF04Mi isolated from goat milk: evaluation of the probiotic potential.

    Science.gov (United States)

    Furtado, Danielle N; Todorov, Svetoslav D; Landgraf, Mariza; Destro, Maria T; Franco, Bernadette D G M

    2014-01-01

    Lactic acid bacteria capable of producing bacteriocins and presenting probiotic potential open innovative technological applications in the dairy industry. In this study, a bacteriocinogenic strain (Lactococcus lactis subsp. lactis DF4Mi) was isolated from goat milk, and studied for its probiotic potential. Lc. lactis DF4Mi was resistant to acidic pH and oxbile, presented co-aggregation with Listeria monocytogenes, and was not affected by several drugs from different generic groups, being sensitive to most tested antibiotics. These properties indicate that this Lc. lactis strain can be used for enhancement of dairy foods safety and quality, in combination with potential probiotic properties. PMID:25477942

  18. Secretion of biologically active murine interleukin-2 by Lactococcus lactis subsp. lactis.

    OpenAIRE

    Steidler, L; Wells, J M; Raeymaekers, A; Vandekerckhove, J; Fiers, W; Remaut, E

    1995-01-01

    Secretion of functional recombinant murine interleukin-2 (mIL2) by Lactococcus lactis was achieved by fusion of the sequence encoding mature mIL2 to the secretion signal leader of the lactococcal usp45 gene placed under transcriptional control of the phage T7 promoter-T7 RNA polymerase expression system. The recombinant mature mIL2 was one of only a few proteins which accumulated in the growth medium. Sequence analysis revealed correct processing at the first amino acid of the mature protein....

  19. Kefir-isolated Lactococcus lactis subsp. lactis inhibits the cytotoxic effect of Clostridium difficile in vitro.

    Science.gov (United States)

    Bolla, Patricia Araceli; Carasi, Paula; Serradell, María de los Angeles; De Antoni, Graciela Liliana

    2013-02-01

    Kefir is a dairy product obtained by fermentation of milk with a complex microbial population and several health-promoting properties have been attributed to its consumption. In this work, we tested the ability of different kefir-isolated bacterial and yeast strains (Lactobacillus kefir, Lb. plantarum, Lactococcus lactis subps. lactis, Saccharomyces cerevisiae and Kluyveromyces marxianus) or a mixture of them (MM) to antagonise the cytopathic effect of toxins from Clostridium difficile (TcdA and TcdB). Cell detachment assays and F-actin network staining using Vero cell line were performed. Although incubation with microbial cells did not reduce the damage induced by C. difficile spent culture supernatant (SCS), Lc. lactis CIDCA 8221 and MM supernatants were able to inhibit the cytotoxicity of SCS to Vero cells. Fraction of Lc. lactis CIDCA 8221 supernatant containing components higher than 10 kDa were responsible for the inhibitory activity and heating of this fraction for 15 min at 100 °C completely abrogated this ability. By dot-blot assay with anti-TcdA or anti-TcdB antibodies, concentration of both toxins seems to be reduced in SCS treated with Lc. lactis CIDCA 8221 supernatant. However, protective effect was not affected by treatment with proteases or proteases-inhibitors tested. In conclusion, we demonstrated that kefir-isolated Lc. lactis CIDCA 8221 secreted heat-sensitive products able to protect eukaryotic cells from cytopathic effect of C. difficile toxins in vitro. Our findings provide new insights into the probiotic action of microorganisms isolated from kefir against virulence factors from intestinal pathogens. PMID:23217732

  20. The structure of the lantibiotic lacticin 481 produced by Lactococcus lactis : location of the thioether bridges

    NARCIS (Netherlands)

    Hooven, Henno W. van den; Lagerwerf, Fija M.; Heerma, Wigger; Haverkamp, Johan; Piard, Jean-Christophe; Hilbers, Cornelis W.; Siezen, Roland J.; Kuipers, Oscar P.; Rollema, Harry S.

    1996-01-01

    The lantibiotic lacticin 481 is a bacteriocin produced by Lactococcus lactis ssp. lactis. This polypeptide contains 27 amino acids, including the unusual residues dehydrobutyrine and the thioether-bridging lanthionine and 3-methyllanthionine. Lacticin 481 belongs to a structurally distinct group of

  1. Effect of X-Prolyl Dipeptidyl Aminopeptidase Deficiency on Lactococcus lactis

    NARCIS (Netherlands)

    Mayo, Baltasar; Kok, Jan; Bockelmann, Wilhelm; Haandrikman, Alfred; Leenhouts, Kees J.; Venema, Gerhardus

    1993-01-01

    The genetic determinant (pepXP) of an X-prolyl dipeptidyl aminopeptidase (PepXP) has recently been cloned and sequenced from both Lactococcus lactis subsp. cremoris (B. Mayo, J. Kok, K. Venema, W. Bockelmann, M. Teuber, H. Reinke, and G. Venema, Appl. Environ. Microbiol. 57:38-44, 1991) and L. lacti

  2. Increasing the heme-dependent respiratory efficiency of Lactococcus lactis by inhibition of lactate dehydrogenase.

    Science.gov (United States)

    Arioli, Stefania; Zambelli, Daniele; Guglielmetti, Simone; De Noni, Ivano; Pedersen, Martin B; Pedersen, Per Dedenroth; Dal Bello, Fabio; Mora, Diego

    2013-01-01

    The discovery of heme-induced respiration in Lactococcus lactis has radically improved the industrial processes used for the biomass production of this species. Here, we show that inhibition of the lactate dehydrogenase activity of L. lactis during growth under respiration-permissive conditions can stimulate aerobic respiration, thereby increasing not only growth efficiency but also the robustness of this organism. PMID:23064338

  3. Generation of Dipeptidyl Peptidase-IV-Inhibiting Peptides from β-Lactoglobulin Secreted by Lactococcus lactis

    Directory of Open Access Journals (Sweden)

    Suguru Shigemori

    2014-01-01

    Full Text Available Previous studies showed that hydrolysates of β-lactoglobulin (BLG prepared using gastrointestinal proteases strongly inhibit dipeptidyl peptidase-IV (DPP-IV activity in vitro. In this study, we developed a BLG-secreting Lactococcus lactis strain as a delivery vehicle and in situ expression system. Interestingly, trypsin-digested recombinant BLG from L. lactis inhibited DPP-IV activity, suggesting that BLG-secreting L. lactis may be useful in the treatment of type 2 diabetes mellitus.

  4. Secretion of TEM beta-lactamase with signal sequences isolated from the chromosome of Lactococcus lactis subsp. lactis.

    OpenAIRE

    Sibakov, M; Koivula, T; von Wright, A.; Palva, I

    1991-01-01

    With TEM beta-lactamase as a reporter gene, a set of expression-secretion-promoting fragments were isolated from the chromosome of Lactococcus lactis subsp. lactis. The fact that only translocated beta-lactamase renders cells resistant to ampicillin allowed direct ampicillin selection with an Escherichia coli vector (pKTH33). The clones showing the greatest ampicillin resistance were subcloned onto a replicon capable of replication in lactic acid bacteria (pVS2), and the nucleotide sequences ...

  5. PpiA, a surface PPIase of the cyclophilin family in Lactococcus lactis.

    Directory of Open Access Journals (Sweden)

    Nicolas Trémillon

    Full Text Available BACKGROUND: Protein folding in the envelope is a crucial limiting step of protein export and secretion. In order to better understand this process in Lactococcus lactis, a lactic acid bacterium, genes encoding putative exported folding factors like Peptidyl Prolyl Isomerases (PPIases were searched for in lactococcal genomes. RESULTS: In L. lactis, a new putative membrane PPIase of the cyclophilin subfamily, PpiA, was identified and characterized. ppiA gene was found to be constitutively expressed under normal and stress (heat shock, H(2O(2 conditions. Under normal conditions, PpiA protein was synthesized and released from intact cells by an exogenously added protease, showing that it was exposed at the cell surface. No obvious phenotype could be associated to a ppiA mutant strain under several laboratory conditions including stress conditions, except a very low sensitivity to H(2O(2. Induction of a ppiA copy provided in trans had no effect i on the thermosensitivity of an mutant strain deficient for the lactococcal surface protease HtrA and ii on the secretion and stability on four exported proteins (a highly degraded hybrid protein and three heterologous secreted proteins in an otherwise wild-type strain background. However, a recombinant soluble form of PpiA that had been produced and secreted in L. lactis and purified from a culture supernatant displayed both PPIase and chaperone activities. CONCLUSIONS: Although L. lactis PpiA, a protein produced and exposed at the cell surface under normal conditions, displayed a very moderate role in vivo, it was found, as a recombinant soluble form, to be endowed with folding activities in vitro.

  6. Detection and characterization of bacteriocin-producing Lactococcus lactis strains Detecção e caracterização de Lactococcus lactis produtores de bacteriocinas

    Directory of Open Access Journals (Sweden)

    Izildinha Moreno

    1999-04-01

    Full Text Available One hundred sixty seven strains of Lactococcus lactis were screened for bacteriocin production by well diffusion assay of GM17 agar. Fourteen (8.4% produced antimicrobial activity other than organic acids, bacteriophages or hydrogen peroxide. The frequency of bacteriocin production ranged from 2% in L. lactis subsp. cremoris up to 12% in L. lactis subsp. lactis. Antimicrobial activities were not observed in any strain of L. lactis subsp. lactis var. diacetylactis. Among thirteen bacteriocin-producing strains and two nisin-producing strains (L. lactis subsp. lactis ATCC 11454 and L. lactis subsp. lactis CNRZ 150, eight (53% were characterized as lactose-positive (Lac+ and proteinase-negative (Prt-. The bacteriocin-producing cultures were also characterized on the basis of plasmid content. All strains had 2 to 7 plasmids with molecular weights varying from 0.5 to 28.1 Mdal. Four strains (ITAL 435, ITAL 436, ITAL 437 and ITAL 438 showed identical profiles and the other were quite distinct.Um total de 167 linhagens de L. lactis foi selecionado para os testes de produção de bacteriocinas pelo método de difusão em poços em agar GM17. Desse total, 14 (8.4% produziram substâncias inibidoras que não foram associadas com ácidos orgânicos, peróxido de hidrogênio e bacteriófagos. A frequência de produção de bacteriocinas variou de 2% em L. lactis subsp. cremoris a 12% em L. lactis subsp. lactis. Nenhuma das linhagens de L. lactis subsp. lactis var. diacetylactis produziu substâncias inibidoras. De 13 linhagens produtoras de bacteriocinas e duas de nisina (L. lactis subsp. lactis ATCC 11454 e L. lactis subsp. lactis CNRZ 150, 8 (53% foram caracterizadas como lactose-positivas (Lac+ e proteinase-negativas (Prt-. As linhagens produtoras de bacteriocinas também foram caracterizadas no seu conteúdo de plasmídios. Elas apresentaram de 2 a 7 plasmídios, com pesos moleculares aproximados de 0.5 a 28.1 Mdal. Quatro linhagens (ITAL 435, ITAL 436

  7. Proteomic Signature of Lactococcus lactis NCDO763 Cultivated in Milk†

    Science.gov (United States)

    Gitton, Christophe; Meyrand, Mickael; Wang, Juhui; Caron, Christophe; Trubuil, Alain; Guillot, Alain; Mistou, Michel-Yves

    2005-01-01

    We have compared the proteomic profiles of L. lactis subsp. cremoris NCDO763 growing in the synthetic medium M17Lac, skim milk microfiltrate (SMM), and skim milk. SMM was used as a simple model medium to reproduce the initial phase of growth of L. lactis in milk. To widen the analysis of the cytoplasmic proteome, we used two different gel systems (pH ranges of 4 to 7 and 4.5 to 5.5), and the proteins associated with the cell envelopes were also studied by two-dimensional electrophoresis. In the course of the study, we analyzed about 800 spots and identified 330 proteins by mass spectrometry. We observed that the levels of more than 50 and 30 proteins were significantly increased upon growth in SMM and milk, respectively. The large redeployment of protein synthesis was essentially associated with an activation of pathways involved in the metabolism of nitrogenous compounds: peptidolytic and peptide transport systems, amino acid biosynthesis and interconversion, and de novo biosynthesis of purines. We also showed that enzymes involved in reactions feeding the purine biosynthetic pathway in one-carbon units and amino acids have an increased level in SMM and milk. The analysis of the proteomic data suggested that the glutamine synthetase (GS) would play a pivotal role in the adaptation to SMM and milk. The analysis of glnA expression during growth in milk and the construction of a glnA-defective mutant confirmed that GS is an essential enzyme for the development of L. lactis in dairy media. This analysis thus provides a proteomic signature of L. lactis, a model lactic acid bacterium, growing in its technological environment. PMID:16269754

  8. Suitability of Lactococcus lactis subsp lactis ATCC 11454 as a protective culture for lightly preserved fish products

    DEFF Research Database (Denmark)

    Wessels, Stephen Wallace; Huss, Hans Henrik

    1996-01-01

    This study is part of strategy to control the human pathogen Listeria monocytogenes in lightly preserved fish products by using food-grade lactic acid bacteria. When the nisin-producing Lactococcus lactis subsp lactis ATCC 11454 was cultured in the same vessel as L-monocytogenes Scott A in brain......-heart infusion broth (BHI) at 30-degrees C, the pathogen declined from 5x10(5) to fewer than 5 cfu ml(-1) within 31 h. The effect was not due to lactic acid inhibition. Growth and nisin production by L- lactis ATCC 11454 were investigated under the conditions of temperature and salt used for light preservation...

  9. Identification of the Minimal Replicon of Lactococcus lactis subsp. lactis UC317 Plasmid pCI305

    OpenAIRE

    Hayes, Finbarr; Daly, Charles; Fitzgerald, Gerald F.

    1990-01-01

    Replication functions of the stable, cryptic 8.7-kilobase (kb) plasmid pCI305 from multi-plasmid-containing Lactococcus lactis subsp. lactis UC317 were studied. Analysis of this replicon was facilitated by the construction of replication probe vectors that consisted of the pBR322 replication region, a pUC18-derived multiple cloning site, and either the cat gene of pC194 (pCI341; 3.1 kb) or the erm gene of pAMβ1 (pCI3330; 4.0 kb). Plasmid pCI305 was introduced into plasmid-free L. lactis subsp...

  10. Adaptation of Lactococcus lactis to high growth temperature leads to a dramatic increase in acidification rate.

    Science.gov (United States)

    Chen, Jun; Shen, Jing; Ingvar Hellgren, Lars; Ruhdal Jensen, Peter; Solem, Christian

    2015-01-01

    Lactococcus lactis is essential for most cheese making, and this mesophilic bacterium has its growth optimum around 30 °C. We have, through adaptive evolution, isolated a mutant TM29 that grows well up to 39 °C, and continuous growth at 40 °C is possible if pre-incubated at a slightly lower temperature. At the maximal permissive temperature for the wild-type, 38 °C, TM29 grows 33% faster and has a 12% higher specific lactate production rate than its parent MG1363, which results in fast lactate accumulation. Genome sequencing was used to reveal the mutations accumulated, most of which were shown to affect thermal tolerance. Of the mutations with more pronounced effects, two affected expression of single proteins (chaperone; riboflavin transporter), two had pleiotropic effects (RNA polymerase) which changed the gene expression profile, and one resulted in a change in the coding sequence of CDP-diglyceride synthase. A large deletion containing 10 genes was also found to affect thermal tolerance significantly. With this study we demonstrate a simple approach to obtain non-GMO derivatives of the important L. lactis that possess properties desirable by the industry, e.g. thermal robustness and increased rate of acidification. The mutations we have identified provide a genetic basis for further investigation of thermal tolerance. PMID:26388459

  11. Some chemical properties of nisin produced by lactococcus lactis

    International Nuclear Information System (INIS)

    The present study was carried out to study the properties of nisin produced by lactococcus lactis FG2 isolated from local un fated cheese. The maximum anti-microbial effect of pure nisin was occurred at ph 6 and 7. Nisin was heat stable from 40 to 90 degree C for 30 min. Molecular weight of nisin was determined by SDS-PAGE, it was 3.0 kDa and after irradiated the microbial cells to 1.5 kGy dose level the molecular weight increased to 3.5 t kDa then decreased at 2 kGy . Storage for two weeks it appeared in dimmer means and had a molecular weight 7 kDa . Using amino acid analyzer reveled that nisin contained a majority of nonpolar amino acids and exhibited cystine in composition . Nisin produced in whey have higher activity than nisin produced in MRS medium but both had the same structure. The results proved that nisin gene is in coded in chromosome and not with plasmid.

  12. The putrescine biosynthesis pathway in Lactococcus lactis is transcriptionally regulated by carbon catabolic repression, mediated by CcpA.

    Science.gov (United States)

    Linares, Daniel M; del Río, Beatriz; Ladero, Victor; Redruello, Begoña; Martín, María Cruz; Fernández, María; Alvarez, Miguel A

    2013-07-01

    Lactococcus lactis is the lactic acid bacterium most widely used by the dairy industry as a starter for the manufacture of fermented products such as cheese and buttermilk. However, some strains produce putrescine from agmatine via the agmatine deiminase (AGDI) pathway. The proteins involved in this pathway, including those necessary for agmatine uptake and conversion into putrescine, are encoded by the aguB, aguD, aguA and aguC genes, which together form an operon. This paper reports the mechanism of regulation of putrescine biosynthesis in L. lactis. It is shown that the aguBDAC operon, which contains a cre site at the promoter of aguB (the first gene of the operon), is transcriptionally regulated by carbon catabolic repression (CCR) mediated by the catabolite control protein CcpA. PMID:23688550

  13. Variable volume fed-batch fermentation for nisin production by Lactococcus lactis subsp. lactis W28.

    Science.gov (United States)

    Wu, Zhaoliang; Wang, Lin; Jing, Yingjun; Li, Xueliang; Zhao, Yanli

    2009-03-01

    A feeding technology that was suitable for improving the nisin production by Lactococcus lactis subsp. lactis W28 was established. The effects of initial sucrose concentration (ISC) in the fermentation broth, feeding time, and feeding rate on the fermentation were studied. It was observed that a fed-batch culture (ISC = 10 g l(-1)) with 100 ml sucrose solution (190 g l(-1)) being evenly fed (9-10 ml h(-1)) into the fermenter after 3-h fermentation gave the best performance in terms of biomass and nisin yield. Under these conditions, the total biomass and the total nisin yield were approximately 23% and 51% higher than those in batch fermentation, respectively. When the sucrose concentration was controlled at 5-10 g l(-1) in variable volume intermittent fed-batch fermentation (VVIF) with ISC = 10 g l(-1), the total biomass and the total nisin yield were 29% and 60% above those in batch fermentation, respectively. The VVIF proved to be effective to eliminate the substrate inhibition by maintaining sucrose at appropriate levels. It is also easy to be scaled up, since various parameters involved in industrial production were taken into account. PMID:18712289

  14. Characterization and antimicrobial activity of natural isolate Lactococcus lactis subsp. lactis BGSM1-19

    Directory of Open Access Journals (Sweden)

    Strahinić Ivana

    2007-01-01

    Full Text Available The strain Lactococcus lactis subsp. lactis BGSM1-19, isolated from traditionally homemade white cheese, produces two bacteriocins: lactococcin B-like bacteriocin named bacteriocin BacSMa and bacteriocin BacSMb which have shown similarity with lacticin RM. Plasmid curing resulted in a low yield (0.33% of BacSMa- BacSMas and BacSMa- BacSMas, BacSMb-, BacSMbs derivatives. The bacteriocin biosynthesis was observed in the logarithmic phase of growth and the production plateau was reached after 8 h of incubation at 30oC, when the culture entered the early stationary phase. Biochemical characterization showed that strain BGSM1-19 retained antimicrobial activity within the pH range of 1 to 12 or after treatment at 100oC for 15 min. However, bacteriocin activity was completely lost after treatment with different proteolytic enzymes. The strain BGSM1-19 contains five plasmids. Plasmid curing indicated that genes coding for bacteriocins synthesis and immunity seem to be located on plasmids. BGSM1-19 exhibited antimicrobial activity against some pathogenic bacteria such as Salmonella paratyphi, Micrococcus flavus, Pseudomonas aeruginosa and Staphylococcus aureus.

  15. Determination of the phosphorylated sugars of the Embden-Meyerhoff-Parnas Pathway in Lactococcus lactis using a fast sampling technique and solid phase extraction

    DEFF Research Database (Denmark)

    Jensen, Niels B.s.; Jokumsen, Kirsten Væver; Villadsen, John

    1999-01-01

    An experimental procedure for the determination of intracellular concentrations of the phosphorylated sugars in the lactic acid bacterium Lactococcus lactis is presented. The first step of the procedure is a rapid sampling of a small volume of the growth medium into 60% (v/v) methanol precooled t...... components. The internal standard was recovered to an extent of 85-95%. (C) 1999 John Wiley & Sons, Inc. Biotechnol Bioeng 63: 356-362, 1999....

  16. Engineering Trehalose Synthesis in Lactococcus lactis for Improved Stress Tolerance ▿ †

    OpenAIRE

    Carvalho, Ana Lúcia; Cardoso, Filipa S.; Bohn, Andreas; Neves, Ana Rute; Santos, Helena

    2011-01-01

    Trehalose accumulation is a common cell defense strategy against a variety of stressful conditions. In particular, our team detected high levels of trehalose in Propionibacterium freudenreichii in response to acid stress, a result that led to the idea that endowing Lactococcus lactis with the capacity to synthesize trehalose could improve the acid tolerance of this organism. To this end, we took advantage of the endogenous genes involved in the trehalose catabolic pathway of L. lactis, i.e., ...

  17. Engineering of Carbon Distribution between Glycolysis and Sugar Nucleotide Biosynthesis in Lactococcus lactis

    OpenAIRE

    Boels, Ingeborg C.; Kleerebezem, Michiel; de Vos, Willem M.

    2003-01-01

    We describe the effects of modulating the activities of glucokinase, phosphofructokinase, and phosphoglucomutase on the branching point between sugar degradation and the biosynthesis of sugar nucleotides involved in the production of exopolysaccharide biosynthesis by Lactococcus lactis. This was realized by using a described isogenic L. lactis mutant with reduced enzyme activities or by controlled expression of the well-characterized genes for phosphoglucomutase or glucokinase from Escherichi...

  18. The Carbohydrate Metabolism Signature of Lactococcus lactis Strain A12 Reveals Its Sourdough Ecosystem Origin

    OpenAIRE

    Passerini, Delphine; Coddeville, Michèle; Le Bourgeois, Pascal; Loubière, Pascal; Ritzenthaler, Paul; Fontagné-Faucher, Catherine; Daveran-Mingot, Marie-Line; Cocaign-Bousquet, Muriel

    2013-01-01

    Lactococcus lactis subsp. lactis strain A12 was isolated from sourdough. Combined genomic, transcriptomic, and phenotypic analyses were performed to understand its survival capacity in the complex sourdough ecosystem and its role in the microbial community. The genome sequence comparison of strain A12 with strain IL1403 (a derivative of an industrial dairy strain) revealed 78 strain-specific regions representing 23% of the total genome size. Most of the strain-specific genes were involved in ...

  19. Estudo dos parâmetros da ultrafiltração de permeado de soro de queijo fermentado por Lactococcus lactis subsp. lactis Ultrafiltration conditions of whey permeate fermented by Lactococcus lactis subsp. lactis

    Directory of Open Access Journals (Sweden)

    Viviane BRONSTEIN

    1998-04-01

    Full Text Available Permeado de soro doce, suplementado com extrato de levedura e peptona, foi utilizado como meio de crescimento para Lactococcus lactis subsp. lactis. No final da fase exponencial de crescimento, o meio de cultura fermentado foi submetido a uma ultrafiltração com o objetivo de concentrar o microrganismo. Foram realizados 6 processamentos diferentes, nos quais variou-se as condições iniciais da ultrafiltração, tendo sido avaliados os seguintes parâmetros: porosidade da membrana, pH e número de células viáveis no permeado e no retentado, a fim de ser estudado a influência de cada parâmetro na taxa de permeação da ultrafiltração. As membranas utilizadas foram eficazes como meio de barragem para o microrganismo Lactococcus lactis subsp. lactis, ficando o retentado com uma média celular de 10(8 ufc/ml e o permeado com uma média celular de 10² ufc/ml. Membranas de diferentes porosidades tiveram taxas de fluxo semelhantes. O aumento da concentração celular provocou a diminuição do fluxo. O pH também influenciou a taxa de permeação, havendo um aumento do fluxo quando foi utilizado um pH inicial mais alto.Cheese whey permeate supplemented with yeast extract and peptone was used as a growth medium for the bacteria Lactococcus lactis subsp. lactis. At the end of the exponential growth phase, the fermented growth medium was ultrafiltered to concentrate the microorganism and to evaluate the effect of the membrane porosity, inicial UF pH and cellular concentration in permeation rate during the ultrafiltration process. The membranes used were efficient as a mean of a barrage for the Lactococcus lactis subsp. lactis. On average, the cellular concentrations were 10(8 CFU/mL and 10² CFU/mL for retentate and permeate, respectively. Membranes of different porosities had very similar flux rates. Better flow rates were obtained with inicial UF pH 6,5 and with the minors micrrorganism concentration.

  20. Effect of Initial Oxygen Concentration on Diacetyl and Acetoin Production by Lactococcus lactis subsp. lactis biovar diacetylactis

    OpenAIRE

    Bassit, Naïma; Boquien, Clair-Yves; Picque, Daniel; Corrieu, Georges

    1993-01-01

    The production of aroma compounds (acetoin and diacetyl) in fresh unripened cheese by Lactococcus lactis subsp. lactis biovar diacetylactis CNRZ 483 was studied at 30°C at different initial oxygen concentrations (0, 21, 50, and 100% of the medium saturation by oxygen). Regardless of the initial O2 concentration, maximal production of these compounds was reached only after all the citrate was consumed. Diacetyl and acetoin production was 0.01 and 2.4 mM, respectively, at 0% oxygen. Maximum ace...

  1. Construction and Expression of β-galactosidase Genetically Engineered Lactococcus lactis

    Institute of Scientific and Technical Information of China (English)

    吕晓英; 张朝武; 裴晓方; 刘祥; 余倩; 刘衡川

    2004-01-01

    Our objective is to solve the lactose malabsorption and intolerance of human beings by combining mlcro-ecology path with genetic engineering technique. Plasmid pMG36e was used to clone and express a β-galactosidase gene from L.delbrueckii bulgaricus strain 1. 1480 in the Lactococcus lactis subsp, cremoris MG1363 and Lactococcus lactis subsp. lactis IL1403. The recombinant plasmid was preserved and proliferated in Escherichia coli ( E. coli) JM109, and transformed into MG1363 and 1L1403 by electroporation. The protein expression was studied. (1) The bifidobacterium culture medium (BBL) was suitable for the growth of the strain 1. 1480. (2) With 13 amino acids at the N-terminus from the vector, β-galactosidase fusion protein (which retained the enzyme activity) could be successfully expressed in E. coli JM109, MG1363 and IL1403, but the expression quantity was larger in the former than in the latter two. (3) The SD sequence designed could be successfully recognized by both the E. coli and the Lactococcus lactis, but the expression level of the non-fusion β-galac-tosidase protein was lower than that of the fusion protein in the same host. The β-galactosidase genetically engineered E.coli JM109 is a useful tool to produce this enzyme in vitro. The signal peptide of the usp45 protein from the Lactococcus lactis can be added before the promoter sequence to promote β-galactosidase secretion from Lactococcus lactis. The potential application of the β-galactosidase genetically engineered MG1363 and IL1403 to cure the lactose malabsorption and lactose intolerance in both health food and medicine is promising。

  2. Elucidating Flux Regulation of the Fermentation Modes of Lactococcus lactis:A Mutlilevel Study

    OpenAIRE

    Chan, Siu Hung Joshua; Solem, Christian; Jensen, Peter Ruhdal

    2014-01-01

    De mange års anvendelse af mælkesyrebakterien Lactococcus lactis (L. lactis) indenfor mejeriindustrien, har været medvirkende til at L. lactis er blevet en af de mest velkarakteriserede bakterier. Denne Gram positive bakterie, som har et lavt GC indhold, har en relativt simpel metabolisme og er let at modificere genetisk. Dette har gjort den til et attraktivt mål for ”metabolic engineering”, bl.a. med henblik på produktion af non-food relaterede kemikalier. Derudover har den status som den fø...

  3. Synthesis and Posttranslational Regulation of Pyruvate Formate-Lyase in Lactococcus lactis

    OpenAIRE

    Melchiorsen, Claus Rix; Jokumsen, Kirsten Væver; Villadsen, John; Johnsen, Mads G.; Israelsen, Hans; Arnau, José

    2000-01-01

    The enzyme pyruvate formate-lyase (PFL) from Lactococcus lactis was produced in Escherichia coli and purified to obtain anti-PFL antibodies that were shown to be specific for L. lactis PFL. It was demonstrated that activated L. lactis PFL was sensitive to oxygen, as in E. coli, resulting in the cleavage of the PFL polypeptide. The PFL protein level and its in vivo activity and regulation were shown by Western blotting, enzyme-linked immunosorbent assay, and metabolite measurement to be depend...

  4. Lactococcus lactis Dihydroorotate Dehydrogenase A Mutants Reveal Important Facets of the Enzymatic Function

    DEFF Research Database (Denmark)

    Nørager, Sofie Charlotte; Arent, S; Björnberg, Olof;

    2003-01-01

    and 1B, and class 2. This division corresponds to differences in cellular location and the nature of the electron acceptor. Herein we report a study of Lactococcus lactis DHODA, a representative of the class 1A enzymes. Based on the DHODA structure we selected seven residues that are highly conserved...

  5. 21 CFR 184.1985 - Aminopeptidase enzyme preparation derived from lactococcus lactis.

    Science.gov (United States)

    2010-04-01

    ...) and 1 CFR part 51. Copies are available from the National Academy Press, 2101 Constitution Ave. NW... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Aminopeptidase enzyme preparation derived from... Aminopeptidase enzyme preparation derived from lactococcus lactis. (a) Aminopeptidase enzyme preparation...

  6. Increasing acidification of nonreplicating Lactococcus lactis Delta thyA mutants by incorporating ATPase activity

    DEFF Research Database (Denmark)

    Pedersen, Martin Bastian; Købmann, Brian Jensen; Jensen, Peter Ruhdal;

    2002-01-01

    Lactococcus lactis MBP71 DeltathyA (thymidylate synthase) cannot synthesize dTTP de novo, and DNA replication is dependent on thymidine in the growth medium. In the nonreplicating state acidification by MBP71 was completely insensitive to bacteriophages (M. B. Pedersen, P. R. Jensen, T. Janzen, and...

  7. Sec-Mediated Transport of Posttranslationally Dehydrated Peptides in Lactococcus lactis

    NARCIS (Netherlands)

    Kuipers, Anneke; Wierenga, Jenny; Rink, Rick; Kluskens, Leon D.; Driessen, Arnold J.M.; Kuipers, Oscar P.; Moll, Gert N.

    2006-01-01

    Nisin is a lanthionine-containing antimicrobial peptide produced by Lactococcus lactis. Its (methyl)lanthionines are introduced by two posttranslational enzymatic steps involving the dehydratase NisB, which dehydrates serine and threonine residues, and the cyclase NisC, which couples these dehydrate

  8. CONTINUOUS MEASUREMENT OF THE CYTOPLASMIC PH IN LACTOCOCCUS-LACTIS WITH A FLUORESCENT PH INDICATOR

    NARCIS (Netherlands)

    MOLENAAR, D; ABEE, T; KONINGS, WN

    1991-01-01

    The cytoplasmic pH of Lactococcus lactis was studied with the fluorescent pH indicator 2',7'-bis-(2-carboxyethyl)-5 (and-6)-carboxyfluorescein (BCECF). A novel method was applied for loading bacterial cells with BCECF, which consists of briefly treating a dense cell suspension with acid in the prese

  9. Quantitative physiology of Lactococcus lactis at extreme low-growth rates

    NARCIS (Netherlands)

    Ercan, O.; Smid, E.J.; Kleerebezem, M.

    2013-01-01

    This paper describes the metabolic adaptation of Lactococcus lactis during the transition from a growing to a non-growing state using retentostat cultivation. Under retentostat cultivation, the specific growth rate decreased from 0.025 h-1 to 0.0001 h-1 in 42 days, while doubling time increased to m

  10. Lactococcus lactis YfiA is necessary and sufficient for ribosome dimerization

    NARCIS (Netherlands)

    Puri, Pranav; Eckhardt, Thomas H; Franken, Linda E; Fusetti, Fabrizia; Stuart, Marc C A; Boekema, Egbert J; Kuipers, Oscar P; Kok, Jan; Poolman, Berend

    2014-01-01

    Dimerization and inactivation of ribosomes in Escherichia coli is a two-step process that involves the binding of ribosome modulation factor (RMF) and hibernation promotion factor (HPF). Lactococcus lactisMG1363 expresses a protein, YfiA(Ll), which associates with ribosomes in the stationary phase o

  11. Mechanism of Citrate Metabolism by an Oxaloacetate Decarboxylase-Deficient Mutant of Lactococcus lactis IL1403

    NARCIS (Netherlands)

    Pudlik, Agata M.; Lolkema, Juke S.

    2011-01-01

    Citrate metabolism in resting cells of Lactococcus lactis IL1403(pFL3) results in the formation of two end products from the intermediate pyruvate, acetoin and acetate (A. M. Pudlik and J. S. Lolkema, J. Bacteriol. 193:706-714, 2011). Pyruvate is formed from citrate following uptake by the transport

  12. An ABC-type multidrug transporter of Lactococcus lactis possesses an exceptionally broad substrate specificity

    NARCIS (Netherlands)

    Poelarends, GJ; Mazurkiewicz, P; Putman, M; Cool, RH; van Veen, HW; Konings, WN

    2000-01-01

    LmrA is a 590-amino acid membrane protein which confers multidrug resistance on Lactococcus lactis cells by extruding amphiphilic compounds from the inner leaflet of the cytoplasmic membrane at the expense of ATP hydrolysis. Its structural and functional characteristics place it in the P-glycoprotei

  13. Fine tuning of the lactate and diacetyl production through promoter engineering in Lactococcus lactis.

    Directory of Open Access Journals (Sweden)

    Tingting Guo

    Full Text Available Lactococcus lactis is a well-studied bacterium widely used in dairy fermentation and capable of producing metabolites with organoleptic and nutritional characteristics. For fine tuning of the distribution of glycolytic flux at the pyruvate branch from lactate to diacetyl and balancing the production of the two metabolites under aerobic conditions, a constitutive promoter library was constructed by randomizing the promoter sequence of the H(2O-forming NADH oxidase gene in L. lactis. The library consisted of 30 promoters covering a wide range of activities from 7,000 to 380,000 relative fluorescence units using a green fluorescent protein as reporter. Eleven typical promoters of the library were selected for the constitutive expression of the H(2O-forming NADH oxidase gene in L. lactis, and the NADH oxidase activity increased from 9.43 to 58.17-fold of the wild-type strain in small steps of activity change under aerobic conditions. Meanwhile, the lactate yield decreased from 21.15 ± 0.08 mM to 9.94 ± 0.07 mM, and the corresponding diacetyl production increased from 1.07 ± 0.03 mM to 4.16 ± 0.06 mM with the intracellular NADH/NAD(+ ratios varying from 0.711 ± 0.005 to 0.383 ± 0.003. The results indicated that the reduced pyruvate to lactate flux was rerouted to the diacetyl with an almost linear flux variation via altered NADH/NAD(+ ratios. Therefore, we provided a novel strategy to precisely control the pyruvate distribution for fine tuning of the lactate and diacetyl production through promoter engineering in L. lactis. Interestingly, the increased H(2O-forming NADH oxidase activity led to 76.95% lower H(2O(2 concentration in the recombinant strain than that of the wild-type strain after 24 h of aerated cultivation. The viable cells were significantly elevated by four orders of magnitude within 28 days of storage at 4°C, suggesting that the increased enzyme activity could eliminate H(2O(2 accumulation and prolong cell survival.

  14. Differential expression of proteins and genes in the lag phase of Lactococcus lactis subsp lactis grown in synthetic medium and reconstituted skim milk

    DEFF Research Database (Denmark)

    Larsen, N.; Boye, Mette; Jakobsen, Marianne;

    2006-01-01

    We investigated protein and gene expression in the lag phase of Lactococcus lactis subsp. lactis CNRZ 157 and compared it to the exponential and stationary phases. By means of two-dimensional polyacrylamide gel electrophoresis, 28 highly expressed lag-phase proteins, implicated in nucleotide meta...

  15. Nucleotide Sequence and Analysis of an orotate transporter-containing plasmid isolated from the Lactococcus lactis ssp. lactis biovar diacetylactis strain DB0410

    DEFF Research Database (Denmark)

    Defoor, Els Marie Celine; Martinussen, Jan

    A new lactococcal plasmid, pDBORO, was isolated from the Lactococcus lactis ssp. lactis biovar diacetylactis strain DB0410 responsible for the sensitivity of DB0410 towards the pyrimidine-analog 5´-fluoroorotate. The plasmid pDBORO amounts to 16404 bp and its complete nucleotide sequence has been...... molecular cloning, we identified the open reading frames on pDBORO necessary for the utilization of orotate as the sole pyrimidine source. Surprisingly, homologs are found on the Lactococcus lactis IL1403 and MG1363 chromosomes despite the fact that they are resistant towards fluoroorotate....

  16. Novel Food-Grade Plasmid Vector Based on Melibiose Fermentation for the Genetic Engineering of Lactococcus lactis

    OpenAIRE

    Boucher, Isabelle; Parrot, Marc; Gaudreau, Hélène; Champagne, Claude P.; Vadeboncoeur, Christian; Moineau, Sylvain

    2002-01-01

    The α-galactosidase gene (aga) and a gene coding for a putative transcriptional regulator from the LacI/GalR family (galR) of Lactococcus raffinolactis ATCC 43920 were cloned and sequenced. When transferred into Lactococcus lactis and Pediococcus acidilactici strains, aga modified the sugar fermentation profile of the strains from melibiose negative (Mel−) to melibiose positive (Mel+). Analysis of galA mutants of L. lactis subsp. cremoris MG1363 indicated that the putative galactose permease ...

  17. Immunogenicity and immunoprotection of porcine circovirus type 2 (PCV2) Cap protein displayed by Lactococcus lactis.

    Science.gov (United States)

    Li, Peng-cheng; Qiao, Xu-wen; Zheng, Qi-sheng; Hou, Ji-bo

    2016-01-27

    The capsid (Cap) protein, an important immunoprotective protein of porcine circovirus type 2 (PCV2), was expressed on the cell surface of the Gram-positive food-grade bacterium, Lactococcus lactis. Cap protein was fused to the peptidoglycan binding domain (known as the protein anchor domain, PA) of the lactococcal AcmA cell-wall hydrolase. The Cap protein fusion was non-covalently rebound to the surface of non-genetically modified, non-living high-binder L. lactis cells (designated Gram-positive enhancer matrix (GEM) particles). Expression of the recombinant GEM-displaying capsid protein (GEM-PA-Cap) was verified by Western blotting and immunofluorescence and transmission electron microscopy assays. To evaluate the immunogenicity of the recombinant Cap protein (rCap), 20 PCV2-seronegative piglets were immunized with the GEM-PA-Cap subunit vaccine, GEM alone, or phosphate-buffered saline (PBS, challenge control and empty control). Each group consisted of five piglets. The results showed that the level of PCV2-specific antibodies in piglets immunized with the GEM-PA-Cap subunit vaccine was significantly higher than that of the piglets immunized with GEM alone or the control group at all the time points post-vaccination (P<0.01). After challenge with the PCV2 wild-type strain, piglets that received the GEM-PA-Cap subunit vaccine showed significantly higher average daily weight gain (DWG) and shorter fever duration than the other two groups (P<0.001). Furthermore, a significant reduction in the gross lung lesion scores and lymph node lesion scores was noted in the GEM-PA-Cap-immunized group compared with the scores of the GEM or PBS-treated group (P<0.01). The results suggest that recombinant rCap displayed by L. lactis GEM particles provided the piglets with significant immunoprotection from PCV2-associated disease. Thus, the novel GEM-PA-Cap subunit vaccine has potential to be considered an effective and safe candidate vaccine against PCV2 infection in piglets. PMID

  18. Heterologous Expression of the Pneumococcal Serotype 14 Polysaccharide in Lactococcus lactis Requires Lactococcal epsABC Regulatory Genes▿ †

    OpenAIRE

    Nierop Groot, M.N.; Godefrooij, J.; Kleerebezem, M.

    2007-01-01

    The pneumococcal serotype 14 polysaccharide was produced in Lactococcus lactis by coexpressing pneumococcal polysaccharide type 14-specific genes (cpsFGHIJKL(14)) with the lactococcal regulatory and priming glucosyltransferase-encoding genes specific for B40 polysaccharide (epsABCD(B40)). The polysaccharide produced by Lactococcus was secreted in the medium, simplifying downstream processing and polysaccharide isolation from culture broth

  19. Cloning and verification of the Lactococcus lactis pyrG gene and characterization of the gene product, CTP synthase

    DEFF Research Database (Denmark)

    Wadskov-Hansen, Steen Lyders Lerche; Willemoës, M.; Martinussen, Jan;

    2001-01-01

    The pyrG gene of Lactococcus lactis subsp. cremoris, encoding CTP synthase, has been cloned and sequenced. It is flanked upstream by an open reading frame showing homology to several aminotransferases and downstream by an open reading frame of unknown function. L. lactis strains harboring disrupted...

  20. Cloning, nucleotide sequence, and regulatory analysis of the Lactococcus lactis dnaJ gene.

    OpenAIRE

    van Asseldonk, M; Simons, A.; Visser, H.; DE VOS W.M.; Simons, G

    1993-01-01

    The dnaJ gene of Lactococcus lactis was isolated from a genomic library of L. lactis NIZO R5 and cloned into pUC19. Nucleotide sequencing revealed an open reading frame of 1,137 bp in length, encoding a protein of 379 amino acids. The deduced amino acid sequence showed homology to the DnaJ proteins of Escherichia coli, Mycobacterium tuberculosis, Bacillus subtilis, and Clostridium acetobutylicum. The level of the dnaJ monocistronic mRNA increased approximately threefold after heat shock. The ...

  1. Effects of Lactococcus lactis on composition of intestinal microbiota: Role of nisin

    DEFF Research Database (Denmark)

    Bernbom, Nete; Licht, Tine Rask; Brogren, Carl-Henrik;

    2006-01-01

    This study examined the ability of (i) pure nisin, (ii) nisin-producing Lactococcus lactis strain CHCC5826, and (iii) the non-nisin-producing L. lactis strain CHCH2862 to affect the composition of the intestinal microbiota of human flora-associated rats. The presence of both the nisin-producing and...... intestine and 200-fold higher in feces than the corresponding concentrations estimated by a biological assay. This indicates that nisin was degraded or inactivated in the gastrointestinal tract, since fragments of this bacteriocin are detected by ELISA while an intact molecule is needed to retain biological...

  2. Gene-cassette for adaptation of Lactococcus lactis to a plant environment

    OpenAIRE

    Doman-Pytka, Monika; Renault, Pierre; Bardowski, Jacek

    2004-01-01

    International audience The generally accepted opinion is that the natural niche for lactococci are plants. Several genes reminiscent of the environmental adaptation of these bacteria to the plant habitat were found as a result of our work on the pullulanase coding region in the Lactococcus lactis IBB500 strain. All genes were located within an 11-kb DNA fragment of a 35-kb plasmid. Analysis of the nucleotide sequence of the 11-kb DNA fragment showed three regions: (i) a middle region - enc...

  3. Physiological function of the maltose operon regulator, MalR, in Lactococcus lactis

    OpenAIRE

    Rådström Peter; Andersson Ulrika

    2002-01-01

    Abstract Background Maltose metabolism is initiated by an ATP-dependent permease system in Lactococcus lactis. The subsequent degradation of intracellular maltose is performed by the concerted action of Pi-dependent maltose phosphorylase and β-phosphoglucomutase. In some Gram-positive bacteria, maltose metabolism is regulated by a maltose operon regulator (MalR), belonging to the LacI-GalR family of transcriptional regulators. A gene presumed to encode MalR has been found directly downstream ...

  4. Plasmid biology of natural Lactococcus lactis strains and molecular mechanisms of bacteriophage-host interaction

    OpenAIRE

    Fallico, Vincenzo

    2011-01-01

    Lacticin 3147, enterocin AS-48, lacticin 481, variacin, and sakacin P are bacteriocins offering promising perspectives in terms of preservation and shelf-life extension of food products and should find commercial application in the near future. The studies detailing their characterization and bio-preservative applications are reviewed. Transcriptomic analyses showed a cell wall-targeted response of Lactococcus lactis IL1403 during the early stages of infection with the lytic bacteriophage c2,...

  5. Some chemical and physical properties of nisin, a small-protein antibiotic produced by Lactococcus lactis.

    OpenAIRE

    Liu, W.; Hansen, J N

    1990-01-01

    Nisin is a small gene-encoded antimicrobial protein produced by Lactococcus lactis that contains unusual dehydroalanine and dehydrobutyrine residues. The reactivity of these residues toward nucleophiles was explored by reacting nisin with a variety of mercaptans. The kinetics of reaction with 2-mercaptoethane-sulfonate and thioglycolate indicated that the reaction pathway includes a binding step. Reaction of nisin at high pH resulted in the formation of multimeric products, apparently as a re...

  6. Lactococcus lactis as an adjuvant and delivery vehicle of antigens against pneumococcal respiratory infections

    OpenAIRE

    Medina, Marcela; Vintiñi, Elisa; Villena, Julio; Raya, Raul; Alvarez, Susana

    2010-01-01

    Most studies of Lactococcus lactis as delivery vehicles of pneumococcal antigens are focused on the effectiveness of mucosal recombinant vaccines against Streptococcus pneumoniae in animal models. At present, there are three types of pneumococcal vaccines: capsular polysaccharide pneumococcal vaccines (PPV), protein-polysaccharide conjugate pneumococcal vaccines (PCV) and protein-based pneumococcal vaccines (PBPV). Only PPV and PCV have been licensed. These vaccines, however, do not represent...

  7. Cloning and Characterization of upp, a Gene Encoding Uracil Phosphoribosyltransferase from Lactococcus lactis

    DEFF Research Database (Denmark)

    Martinussen, Jan; Hammer, Karin

    1994-01-01

    Uracil phosphoribosyltransferase catalyzes the key reaction in the salvage of uracil in many microorganisms. The gene encoding uracil phosphoribosyltransferase (upp) was cloned from Lactococcus lactis subsp. cremoris MG1363 by complementation of an Escherichia coli mutant. The gene was sequenced......-negative bacterial strains. The phenotype of the uracil phosphoribosyltransferase-deficient strain was established. Surprisingly, the upp strain is resistant only to very low concentrations of 5-fluorouracil. Secondary mutants in thymidine phosphorylase and thymidine kinase were isolated by selection for resistance...

  8. Purification and Characterization of an Aminopeptidase from Lactococcus lactis subsp. cremoris Wg2

    OpenAIRE

    Tan, P. S. T.; Konings, W. N.

    1990-01-01

    An aminopeptidase was purified to homogeneity from a crude cell extract of Lactococcus lactis subsp. cremoris Wg2 by a procedure that included diethyl-aminoethane-Sephacel chromatography, phenyl-Sepharose chromatography, gel filtration, and high-performance liquid chromatography over an anion-exchange column. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis of the purified enzyme showed a single protein band with a molecular weight of 95,000. The aminopeptidase was capable of degradi...

  9. Peptide uptake is essential for growth of Lactococcus lactis on the milk protein casein.

    OpenAIRE

    Smid, E. J.; Plapp, R; Konings, W. N.

    1989-01-01

    The chlorated dipeptide L-alanyl-beta-chloro-L-alanine (diACA) is very toxic for Lactococcus lactis. Spontaneous mutants resistant to the dipeptide were isolated from plates. The presence and activities of cell wall-associated proteinase, different peptidases in cell extracts, amino acid transport systems, and di- and oligopeptide transport systems were examined and compared in a diACA-resistant mutant and the wild type. Only the rates of di- and tripeptide transport were found to be signific...

  10. Regulation of Exopolysaccharide Production by Lactococcus lactis subsp. cremoris by the Sugar Source

    OpenAIRE

    Looijesteijn, Petronella J.; Boels, Ingeborg C.; Kleerebezem, Michiel; Hugenholtz, Jeroen

    1999-01-01

    Lactococcus lactis produced more exopolysaccharide (EPS) on glucose than on fructose as the sugar substrate, although the transcription level of the eps gene cluster was independent of the sugar source. A major difference between cells grown on the two substrates was the capacity to produce sugar nucleotides, the EPS precursors. However, the activities of the enzymes required for the synthesis of nucleotide sugars were not changed upon growth on different sugars. The activity of fructosebisph...

  11. Prevention of gastrointestinal lead poisoning using recombinant Lactococcus lactis expressing human metallothionein-I fusion protein

    OpenAIRE

    Xue Xiao; Changbin Zhang; Dajun Liu; Weibin Bai; Qihao Zhang; Qi Xiang; Yadong Huang; Zhijian Su

    2016-01-01

    Low-level lead poisoning is an insidious disease that affects millions of children worldwide, leading to biochemical and neurological dysfunctions. Blocking lead uptake via the gastrointestinal tract is an important prevention strategy. With this in mind, we constructed the recombinant Lactococcus lactis strain pGSMT/MG1363, which constitutively expressed the fusion protein glutathione S-transferase (GST)–small molecule ubiquitin-like modifier protein (SUMO)–metallothionein-I (GST-SUMO-MT). T...

  12. Oxidative Stress at High Temperatures in Lactococcus lactis Due to an Insufficient Supply of Riboflavin

    DEFF Research Database (Denmark)

    Shen, Jing; Solem, Christian; Jensen, Peter Ruhdal;

    2013-01-01

    Lactococcus lactis MG1363 was found to be unable to grow at temperatures above 37°C in a defined medium without riboflavin, and the cause was identified to be dissolved oxygen introduced during preparation of the medium. At 30°C, growth was unaffected by dissolved oxygen and oxygen was consumed...... riboflavin to the medium, it was possible to improve growth and oxygen consumption at 37°C, and this also normalized the [ATP]-to-[ADP] ratio. A codon-optimized redox-sensitive green fluorescent protein (GFP) was introduced into L. lactis and revealed a more oxidized cytoplasm at 37°C than at 30°C. These...... results indicate that L. lactis suffers from heat-induced oxidative stress at increased temperatures. A decrease in intracellular flavin adenine dinucleotide (FAD), which is derived from riboflavin, was observed with increasing growth temperature, but the presence of riboflavin made the decrease smaller...

  13. Angiotensin-converting enzyme inhibitory activity of milk fermented by wild and industrial Lactococcus lactis strains.

    Science.gov (United States)

    Rodríguez-Figueroa, J C; Reyes-Díaz, R; González-Córdova, A F; Troncoso-Rojas, R; Vargas-Arispuro, I; Vallejo-Cordoba, B

    2010-11-01

    Angiotensin I-converting enzyme inhibitory (ACEI) activity was evaluated and compared in milk fermented by wild and commercial starter culture Lactococcus lactis strains after 48 h of incubation. The highest ACEI activities were found in WSE from milk inoculated with wild L. lactis strains isolated from artisanal dairy products and commercial starter cultures. On the other hand, the lowest ACEI activities were found in WSE from milk inoculated with wild strains isolated from vegetables. Moreover, the IC(50) values (concentration that inhibits 50% activity) of WSE from artisanal dairy products were the lowest, indicating that these fractions were the most effective in inhibiting 50% of ACE activity. In fact, a strain isolated from artisanal cheese presented the lowest IC(50) (13 μg/mL). Thus, it appears that wild L. lactis strains isolated from artisanal dairy products and commercial starter cultures showed good potential for the production of fermented dairy products with ACEI properties. PMID:20965317

  14. Physiochemical parameters optimization for enhanced nisin production by Lactococcus lactis (MTCC 440

    Directory of Open Access Journals (Sweden)

    Puspadhwaja Mall

    2010-02-01

    Full Text Available The influence of various physiochemical parameters on the growth of Lactococcus lactis sub sp. lactis MTCC 440 was studied at shake flask level for 20 h. Media optimization (MRS broth was studied to achieve enhanced growth of the organism and also nisin production. Bioassay of nisin was done with agar diffusion method using Streptococcus agalactae NCIM 2401 as indicator strain. MRS broth (6%, w/v with 0.15μg/ml of nisin supplemented with 0.5% (v/v skimmed milk was found to be the best for nisin production as well as for growth of L lactis. The production of nisin was strongly influenced by the presence of skimmed milk and nisin in MRS broth. The production of nisin was affected by the physical parameters and maximum nisin production was at 30(0C while the optimal temperature for biomass production was 37(0C.

  15. Fate of Lactococcus lactis starter cultures during late ripening in cheese models.

    Science.gov (United States)

    Ruggirello, Marianna; Cocolin, Luca; Dolci, Paola

    2016-10-01

    The presence of Lactococcus lactis, commonly employed as starter culture, was, recently, highlighted and investigated during late cheese ripening. Thus, the main goal of the present study was to assess the persistence and viability of this microorganism throughout manufacturing and ripening of model cheeses. Eight commercial starters, constituted of L. lactis subsp. lactis and L. lactis subsp. cremoris, were inoculated in pasteurized milk in order to manufacture miniature cheeses, ripened for six months. Samples were analysed at different steps (milk after inoculum, curd after cutting, curd after pressing and draining, cheese immediately after salting and cheese at 7, 15, 30, 60, 90, 120, 150 and 180 days of ripening) and submitted to both culture-dependent (traditional plating on M17) and -independent analysis (reverse transcription-quantitative PCR). On the basis of direct RNA analysis, L. lactis populations were detected in all miniature cheeses up to the sixth month of ripening, confirming the presence of viable cells during the whole ripening process, including late stages. Noteworthy, L. lactis was detected by RT-qPCR in cheese samples also when traditional plating failed to indicate its presence. This discrepancy could be explain with the fact that lactococci, during ripening process, enter in a stressed physiological state (viable not culturable, VNC), which might cause their inability to grow on synthetic medium despite their viability in cheese matrix. Preliminary results obtained by "resuscitation" assays corroborated this hypothesis and 2.5% glucose enrichment was effective to recover L. lactis cells in VNC state. The capability of L. lactis to persist in late ripening, and the presence of VNC cells which are known to shift their catabolism to peptides and amino acids consumption, suggests a possible technological role of this microorganism in cheese ripening with a possible impact on flavour formation. PMID:27375251

  16. Properties and genomic analysis of Lactococcus garvieae lysogenic bacteriophage PLgT-1, a new member of Siphoviridae, with homology to Lactococcus lactis phages.

    Science.gov (United States)

    Hoai, Truong Dinh; Nishiki, Issei; Yoshida, Terutoyo

    2016-08-15

    The lysogenic phage PLgT-1 is highly prevalent in Lactococcus garvieae, which is a serious bacterial pathogen in marine fish. Therefore, information regarding this phage is one of the key factors to predict the evolution of this bacterium. However, many properties of this phage, its complete genome sequence, and its relationship with other viral communities has not been investigated to date. Here, we demonstrated that the phage PLgT-1 was not only induced by an induction agent (Mitomycin C), but could be released frequently during cell division in a nutrient-rich environment or in natural seawater. Integration of PLgT-1 into non-lysogenic bacteria via transduction changed the genotype, resulting in the diversification of L. garvieae. The complete DNA sequence of PLgT-1 was also determined. This phage has a dsDNA genome of 40,273bp with 66 open reading frames (ORFs). Of these, the biological functions of 24 ORFs could be predicted but those of 42 ORFs are unknown. Thus, PLgT-1 is a novel phage with several novel proteins encoded in its genome. The strict MegaBLAST search program for the PLgT-1 genome revealed that this phage had no similarities with other previously investigated phages specific to L. garvieae (WP-2 and GE1). Notably, PLgT-1 was relatively homologous with several phages of Lactococcus lactis and 17 of the 24 predicted proteins encoded in PLgT-1 were homologous with the deduced proteins of various phages from these dairy bacteria. Comparative genome analysis revealed that the L. garvieae phage PLgT-1 was most closely related to the L. lactis phage TP712. However, they differed from each other in genome size and gene arrangement. The results obtained in this study suggest that the lysogenic phage PLgT-1 is a new member of the family Siphoviridae and has been involved in horizontal gene exchange with microbial communities, especially with L. lactis and its phages. PMID:27234995

  17. Lactococcus lactis NCC 2287 Alleviates Food Allergic Manifestations in Sensitized Mice by Reducing IL-13 Expression Specifically in the Ileum

    Directory of Open Access Journals (Sweden)

    Adrian W. Zuercher

    2012-01-01

    Full Text Available Objective. Utilizing a food allergy murine model, we have investigated the intrinsic antiallergic potential of the Lactococcus lactis NCC 2287 strain. Methods. BALB/c mice were sensitized at weekly intervals with ovalbumin (OVA plus cholera toxin (CT by the oral route for 7 weeks. In this model, an oral challenge with a high dose of OVA at the end of the sensitization period leads to clinical symptoms. Lactococcus lactis NCC 2287 was given to mice via the drinking water during sensitization (prevention phase or after sensitization (management phase. Results. Lactococcus lactis NCC 2287 administration to sensitized mice strikingly reduced allergic manifestations in the management phase upon challenge, when compared to control mice. No preventive effect was observed with the strain. Lactococcus lactis NCC 2287 significantly decreased relative expression levels of the Th-2 cytokine, IL-13, and associated chemokines CCL11 (eotaxin-1 and CCL17 (TARC in the ileum. No effect was observed in the jejunum. Conclusion/Significance. These results taken together designate Lactococcus lactis NCC 2287 as a candidate probiotic strain appropriate in the management of allergic symptoms.

  18. Bacteriocinogenic Lactococcus lactis subsp. lactis DF04Mi isolated from goat milk: Application in the control of Listeria monocytogenes in fresh Minas-type goat cheese

    OpenAIRE

    Danielle N. Furtado; Todorov, Svetoslav D.; Mariza Landgraf; Destro, Maria T.; Bernadette D.G.M. Franco

    2015-01-01

    Listeria monocytogenes is a pathogen frequently found in dairy products. Its control in fresh cheeses is difficult, due to the psychrotrophic properties and salt tolerance. Bacteriocinogenic lactic acid bacteria (LAB) with proven in vitro antilisterial activity can be an innovative technological approach but their application needs to be evaluated by means of in situ tests. In this study, a novel bacteriocinogenic Lactococcus lactis strain ( Lc . lactis DF4Mi), isolated from raw goat milk, wa...

  19. Growth Phase-Dependent Proteomes of the Malaysian Isolated Lactococcus lactis Dairy Strain M4 Using Label-Free Qualitative Shotgun Proteomics Analysis

    Directory of Open Access Journals (Sweden)

    Theresa Wan Chen Yap

    2014-01-01

    Full Text Available Lactococcus lactis is the most studied mesophilic fermentative lactic acid bacterium. It is used extensively in the food industry and plays a pivotal role as a cell factory and also as vaccine delivery platforms. The proteome of the Malaysian isolated L. lactis M4 dairy strain, obtained from the milk of locally bred cows, was studied to elucidate the physiological changes occurring between the growth phases of this bacterium. In this study, ultraperformance liquid chromatography nanoflow electrospray ionization tandem mass spectrometry (UPLC- nano-ESI-MSE approach was used for qualitative proteomic analysis. A total of 100 and 121 proteins were identified from the midexponential and early stationary growth phases, respectively, of the L. lactis strain M4. During the exponential phase, the most important reaction was the generation of sufficient energy, whereas, in the early stationary phase, the metabolic energy pathways decreased and the biosynthesis of proteins became more important. Thus, the metabolism of the cells shifted from energy production in the exponential phase to the synthesis of macromolecules in the stationary phase. The resultant proteomes are essential in providing an improved view of the cellular machinery of L. lactis during the transition of growth phases and hence provide insight into various biotechnological applications.

  20. Interaction between the genomes of Lactococcus lactis and phages of the P335 species.

    Directory of Open Access Journals (Sweden)

    William John Kelly

    2013-08-01

    Full Text Available Phages of the P335 species infect Lactococcus lactis and have been particularly studied because of their association with strains of L. lactis subsp. cremoris used as dairy starter cultures. Unlike other lactococcal phages, those of the P335 species may have a temperate or lytic lifestyle, and are believed to originate from the starter cultures themselves. We have sequenced the genome of L. lactis subsp. cremoris KW2 isolated from fermented corn and found that it contains an integrated P335 species prophage. This 41 kb prophage (ΦKW2 has a mosaic structure with functional modules that are highly similar to several other phages of the P335 species associated with dairy starter cultures. Comparison of the genomes of 26 phages of the P335 species, with either a lytic or temperate lifestyle, shows that they can be divided into three groups and that the morphogenesis gene region is the most conserved. Analysis of these phage genomes in conjunction with the genomes of several L. lactis strains shows that prophage insertion is site specific and occurs at seven different chromosomal locations. Exactly how induced or lytic phages of the P335 species interact with carbohydrate cell surface receptors in the host cell envelope remains to be determined. Genes for the biosynthesis of a variable cell surface polysaccharide and for lipoteichoic acids are found in L. lactis and are the main candidates for phage receptors, as the genes for other cell surface carbohydrates have been lost from dairy starter strains. Overall, phages of the P335 species appear to have had only a minor role in the adaptation of L. lactis subsp. cremoris strains to the dairy environment, and instead they appear to be an integral part of the L. lactis chromosome. There remains a great deal to be discovered about their role, and their contribution to the evolution of the bacterial genome.

  1. Transcriptome analysis of Lactococcus lactis subsp. lactis during milk acidification as affected by dissolved oxygen and the redox potential.

    Science.gov (United States)

    Larsen, Nadja; Moslehi-Jenabian, Saloomeh; Werner, Birgit Brøsted; Jensen, Maiken Lund; Garrigues, Christel; Vogensen, Finn Kvist; Jespersen, Lene

    2016-06-01

    Performance of Lactococcus lactis as a starter culture in dairy fermentations depends on the levels of dissolved oxygen and the redox state of milk. In this study the microarray analysis was used to investigate the global gene expression of L. lactis subsp. lactis DSM20481(T) during milk acidification as affected by oxygen depletion and the decrease of redox potential. Fermentations were carried out at different initial levels of dissolved oxygen (dO2) obtained by milk sparging with oxygen (high dO2, 63%) or nitrogen (low dO2, 6%). Bacterial exposure to high initial oxygen resulted in overexpression of genes involved in detoxification of reactive oxygen species (ROS), oxidation-reduction processes, biosynthesis of trehalose and down-regulation of genes involved in purine nucleotide biosynthesis, indicating that several factors, among them trehalose and GTP, were implicated in bacterial adaptation to oxidative stress. Generally, transcriptional changes were more pronounced during fermentation of oxygen sparged milk. Genes up-regulated in response to oxygen depletion were implicated in biosynthesis and transport of pyrimidine nucleotides, branched chain amino acids and in arginine catabolic pathways; whereas genes involved in salvage of nucleotides and cysteine pathways were repressed. Expression pattern of genes involved in pyruvate metabolism indicated shifts towards mixed acid fermentation after oxygen depletion with production of specific end-products, depending on milk treatment. Differential expression of genes, involved in amino acid and pyruvate pathways, suggested that initial oxygen might influence the release of flavor compounds and, thereby, flavor development in dairy fermentations. The knowledge of molecular responses involved in adaptation of L. lactis to the shifts of redox state and pH during milk fermentations is important for the dairy industry to ensure better control of cheese production. PMID:27015296

  2. 重组乳酸乳球菌表达外源产物在养猪生产中的潜在应用%Potential Application of Expression of Exogenous Products by Recombinant Lactococcus lactis in Pig Production

    Institute of Scientific and Technical Information of China (English)

    张攀; 许蒙蒙; 林燕; 方正锋; 车炼强; 吴德; 徐盛玉

    2015-01-01

    Lactococcus lactis is a typical representative bacterium of lactic acid bacteria. With the deepening re-search in molecular biology of Lactococcus lactis, recombinant Lactococcus lactis is extensively researched as a bacterial carrier in the field of animal husbandry and veterinary due to having prebiotic effects and using expres-sion of exogenous functional proteins. Meanwhile, Lactococcus lactis also showed good potential in pig indus-try, which could provide a new way for the healthy development of pig industry. This paper reviewed the ex-pression of exogenous products of recombinant Lactococcus lactis ( epidermal growth factor, lactoferrin, etc. ) for improving pig performance as well as a vaccine carrier for prevention and treatment of swine diseases.%乳酸乳球菌是乳酸菌中的典型代表,随着乳酸乳球菌分子生物学研究的不断深入,重组乳酸乳球菌因具有益生作用和表达外源功能蛋白的双重功能被用做载体菌在畜牧兽医学领域广泛研究,同时在养猪产业中也显示出良好的应用潜力,可为养猪业的健康发展提供新的思路. 本文主要对重组乳酸乳球菌表达表皮生长因子、乳铁蛋白等外源产物来提高猪生产性能以及作为疫苗呈递载体用于猪疾病防治的应用做一综述.

  3. The carB Gene Encoding the Large Subunit of Carbamoylphosphate Synthetase from Lactococcus lactis Is Transcribed Monocistronically

    OpenAIRE

    Martinussen, Jan; Hammer, Karin

    1998-01-01

    The biosynthesis of carbamoylphosphate is catalyzed by the heterodimeric enzyme carbamoylphosphate synthetase. The genes encoding the two subunits of this enzyme in procaryotes are normally transcribed as an operon, but the gene encoding the large subunit (carB) in Lactococcus lactis is shown to be transcribed as an isolated unit. Carbamoylphosphate is a precursor in the biosynthesis of both pyrimidine nucleotides and arginine. By mutant analysis, L. lactis is shown to possess only one carB g...

  4. Glucose Metabolism in Lactococcus lactis MG1363 under Different Aeration Conditions: Requirement of Acetate To Sustain Growth under Microaerobic Conditions

    OpenAIRE

    Nordkvist, Mikkel; Jensen, Niels Bang Siemsen; Villadsen, John

    2003-01-01

    Lactococcus lactis subsp. lactis MG1363 was grown in batch cultures on a defined medium with glucose as the energy source under different aeration conditions, namely, anaerobic conditions, aerobic conditions, and microaerobic conditions with a dissolved oxygen tension of 5% (when saturation with air was used as the reference). The maximum specific growth rate was high (0.78 to 0.91 h−1) under all aeration conditions but decreased with increasing aeration, and more than 90% of the glucose was ...

  5. Oral Treatment with Lactococcus lactis Expressing Staphylococcus hyicus Lipase Enhances Lipid Digestion in Pigs with Induced Pancreatic Insufficiency

    OpenAIRE

    Drouault, Sophie; Juste, Catherine; Marteau, Philippe; Renault, Pierre; Corthier, Gérard

    2002-01-01

    The Staphylococcus hyicus lip gene was cloned in Lactococcus lactis. Pancreatic insufficiency was induced by ligation of the pancreatic duct in pigs. In pigs who had undergone pancreatic ligation, the coefficient of fat absorption was higher after consumption of lipase-expressing L. lactis (91.9% ± 3.7%) than that after consumption of the inactive control strain (78.4% ± 2.4%).

  6. Heterologous production of methionine-γ-lyase from brevibacterium linens in lactococcus lactis and formation of volatile sulfur compounds

    OpenAIRE

    Hanniffy, Sean; Philo, Mark; Peláez, Carmen; Gasson, M. J.; Requena, Teresa; Martínez-Cuesta, M. Carmen

    2009-01-01

    The conversion of methionine to volatile sulfur compounds (VSCs) is of great importance in flavor formation during cheese ripening and is the focus of biotechnological approaches toward flavor improvement. A synthetic mgl gene encoding methionine-γ-lyase (MGL) from Brevibacterium linens BL2 was cloned into a Lactococcus lactis expression plasmid under the control of the nisin-inducible promoter PnisA. When expressed in L. lactis and purified as a recombinant protein, MGL was shown to degrade ...

  7. Proton motive force-driven and ATP-dependent drug extrusion systems in multidrug-resistant Lactococcus lactis.

    OpenAIRE

    Bolhuis, H.; Molenaar, D.; POELARENDS, G; VANVEEN, HW; Poolman, B; Driessen, AJM; KONINGS, WN

    1994-01-01

    Three mutants of Lactococcus lactis subsp. lactis MG1363, termed Eth(R), Dau(R), and Rho(R), were selected for resistance to high concentrations of ethidium bromide, daunomycin, and rhodamine 6G, respectively. These mutants were found to be cross resistant to a number of structurally and functionally unrelated drugs, among which were typical substrates of the mammalian multidrug transporter (P-glycoprotein) such as daunomycin, quinine, actinomycin D, gramicidin D, and rhodamine 6G. The three ...

  8. Analysis of heat shock gene expression in Lactococcus lactis MG1363

    DEFF Research Database (Denmark)

    Arnau, José; Sørensen, Kim; Appel, Karen Fuglede;

    1996-01-01

    The induction of the heat shock response in Lactococcus lactis subsp. cremoris strain MG1363 was analysed at the RNA level using a novel RNA isolation procedure to prevent degradation. Cloning of the dnaJ and groEL homologous was carried out. Nothern blot analysis showed a similar induction pattern...... heat shock response in L. lactis MG1363 is presented. A gene located downstream of the dnaK operon in strain MG1363, named orf4, was shown not to be regulated by heat shock......., although maximum induction was observed earlier for orf1 and grpE. Novel transcript sizes were detected in heat-shocked cells. The induction kinetics observed for ftsH suggested a different regulation for this gene. Experimental evidence for a prenounced transcriptional regulation being involved in the...

  9. The pyrimidine operon pyrRPB-carA from Lactococcus lactis

    DEFF Research Database (Denmark)

    Martinussen, Jan; Schallert, J.; Andersen, Birgit;

    2001-01-01

    The four genes pyrR, pyrP, pyrB, and carA were found to constitute an operon in Lactococcus lactis subsp, lactis MG1363. The functions of the different genes were established by mutational analysis. The first gene in the operon is the pyrimidine regulatory gene, pyrR, which is responsible for the...... regulation of the expression of the pyrimidine biosynthetic genes leading to UMP formation. The second gene encodes a membrane-bound high-affinity uracil permease, required for utilization of exogenous uracil. The last two genes in the operon, pyrB and carA, encode pyrimidine biosynthetic enzymes; aspartate...... transcarbamoylase (pyrB) is the second enzyme in the pathway, whereas carbamoyl-phosphate synthetase subunit A (carA) is the small subunit of a heterodimeric enzyme, catalyzing the formation of carbamoyl phosphate. The carA gene product is shown to be required for both pyrimidine and arginine biosynthesis. The...

  10. Characterization of Lactococcus lactis mutants with improved performance at high temperatures and potential dairy applications

    DEFF Research Database (Denmark)

    Chen, Jun

    Lactococcus lactis (L. lactis) is a Gram-positive mesophile, which has considerable importance in the dairy industry for production of cheese and butter milk, and which carries the “GRAS” (generally recognized as safe) designation. Temperature has a great impact on dairy fermentation processes...... latter because the increased energy consumption at high temperatures potentially could stimulate glycolysis. However in many cases the fitness is affected and mostly negative effects on productivity are observed. In this study, the non-GMO approach, experimental adaptation, was employed for isolating...... lactate production rates when compared to MG1363 at high temperatures. Whole genome re-sequencing identified 13 SNPs, one DIP and one large deletion in TM29, and additional sequencing of the isolated intermediates indicated dynamic accumulation of mutations with rising fitness in a temporal order. DNA...

  11. Increased biomass yield of Lactococcus lactis during energetically limited growth and respiratory conditions

    DEFF Research Database (Denmark)

    Købmann, Brian Jensen; Blank, Lars Mathias; Solem, Christian;

    2008-01-01

    subtracting these contributions, approx. 0.3 mol of ATP/mol of glucose remained unaccounted for. A similar response to respiratory conditions (0.2 mol of ATP/mol of glucose) was observed in a mutant that had a decreased glucose uptake rate during growth on glucose caused by disruption of the PTSmannose......Lactococcus lactis is known to be capable of respiration under aerobic conditions in the presence of haemin. In the present study the effect of respiration on ATP production during growth on different sugars was examined. With glucose as the sole carbon source, respiratory conditions in L. lactis...... MG1363 resulted in only a minor increase, 21%, in biomass yield. Since ATP production through substrate-level phosphorylation was essentially identical with and without respiration, the increased biomass yield was a result of energy-saving under respiratory conditions estimated to be 0.4 mol of ATP...

  12. Exploring optimization parameters to increase ssDNA recombineering in Lactococcus lactis and Lactobacillus reuteri

    OpenAIRE

    van Pijkeren, Jan-Peter; Neoh, Kar Mun; Sirias, Denise; Findley, Anthony S.; Britton, Robert A.

    2012-01-01

    Single-stranded DNA (ssDNA) recombineering is a technology which is used to make subtle changes in the chromosome of several bacterial genera. Cells which express a single-stranded DNA binding protein (RecT or Bet) are transformed with an oligonucleotide which is incorporated via an annealing and replication-dependent mechanism. By in silico analysis we identified ssDNA binding protein homologs in the genus Lactobacillus and Lactococcus lactis. To assess whether we could further improve the r...

  13. Oxidative Stress at High Temperatures in Lactococcus lactis Due to an Insufficient Supply of Riboflavin

    OpenAIRE

    Chen, Jun; Shen, Jing; Solem, Christian; Jensen, Peter Ruhdal

    2013-01-01

    Lactococcus lactis MG1363 was found to be unable to grow at temperatures above 37°C in a defined medium without riboflavin, and the cause was identified to be dissolved oxygen introduced during preparation of the medium. At 30°C, growth was unaffected by dissolved oxygen and oxygen was consumed quickly. Raising the temperature to 37°C resulted in severe growth inhibition and only slow removal of dissolved oxygen. Under these conditions, an abnormally low intracellular ratio of [ATP] to [ADP] ...

  14. Investigation of glycerol assimilation and cofactor metabolism in Lactococcus lactis

    DEFF Research Database (Denmark)

    Holm, Anders Koefoed

    The production of biodiesel has been steadily increasing during the last decade, and with it crude glycerol as a byproduct. Despite being rich in glycerol, the increased supply has saturated the demand for glycerol, making purification a non-viable option. The background for this project was to...... evaluated were: anaerobic, aerobic and respiration permissive growth in combination with either glycerol as a sole substrate or with co-metabolization of glycerol with common sugar substrates. Although no growth on glycerol was seen, both positive and detrimental effects were observed from cultures with...... glycerol supplementation. The positive effects were observed from cultivation of L. lactis IL1403 with trehalose as a substrate under aerated conditions. Under these conditions, the supplementation of glycerol would cause an increase in biomass production of over night cultures. The growth rate of the...

  15. Expression of Helicobacter pylori hspA Gene in Lactococcus lactis NICE System and Experimental Study on Its Immunoreactivity

    Directory of Open Access Journals (Sweden)

    Xiao-Juan Zhang

    2015-01-01

    Full Text Available Aim. The aim of this study was to develop an oral Lactococcus lactis (L. lactis vaccine against Helicobacter pylori (H. pylori. Methods. After L. lactis NZ3900/pNZ8110-hspA was constructed, growth curves were plotted to study whether the growth of recombinant L. lactis was affected after hspA was cloned into L. lactis and whether the growth of empty bacteria, empty plasmid bacteria, and recombinant L. lactis was affected by different concentrations of Nisin; SDS-PAGE and Western blot were adopted, respectively, to detect the HspA expressed by recombinant L. lactis and its immunoreactivity. Results. There was no effect observed from the growth curve after exogenous gene hspA was cloned into L. lactis NZ3900; different concentrations of Nisin did not affect the growth of NZ3900 and NZ3900/pNZ8110, while different concentrations of Nisin inhibited the growth of NZ3900/pNZ8110-hspA except 10 ng/mL Nisin. No HspA strip was observed from SDS-PAGE. Western blot analysis showed that HspA expressed by recombinant bacteria had favorable immunoreactivity. Conclusion. The growth of recombinant L. lactis was suppressed even though a small amount of HspA had been induced to express. Therefore recombinant L. lactis only express HspA which was not suitable to be oral vaccine against Helicobacter pylori.

  16. An evaluation and partial characterization of a bacteriocin produced by Lactococcus lactis subsp lactis ST1 isolated from goat milk.

    Science.gov (United States)

    Taheri, Parinaz; Samadi, Nasrin; Ehsani, Mohammad Reza; Khoshayand, Mohammad Reza; Jamalifar, Hossein

    2012-10-01

    A bacteriocin-like inhibitory substance producing Lactococcus lactis subsp lactis strain, ST1, isolated from goat milk of Iranian origin and with broad spectrum of activity and desirable technical properties was used for evaluating some futures of bacteriocin inhibitory activity. Cell growth and bacteriocin production studies were carried out in MRS medium incubated statically under uncontrolled pH condition. The antibacterial activity presented a primary metabolite pattern and showed a rapid decrease at the stationary phase. Microaerobiosis and capnophily growth conditions resulted in higher bacteriocin production while aerobiosis showed negative effect on both cell growth and bacteriocin production. Bacteriocin production, on the other hand, was favored in MRS broth (pH; 6.5) inoculated with 0.1 ml l(-1) fresh culture when incubation was carried out at 30 °C. This indicated that the conditions resulted in higher levels of growth were frequently favoring bacteriocin production by ST1 as well. Decrease in activity, at the stationary growth phase, was much pronounced in favored growth condition. Nutrient depletion, deferent effect of low pH on bacteriocin production and/or protein degradation seemed more responsible for this phenomenon. The study also provided further data on new method for bacteriocin release from the cell wall of producer. It was clearly shown that both heating and ultrasound shock for 5 min at pH 2 could increase bacteriocin activity significantly. The release was more pronounced in the presence of 0.5% Tween80. PMID:24031976

  17. An evaluation and partial characterization of a bacteriocin produced by Lactococcus lactis subsp lactis ST1 isolated from goat milk

    Directory of Open Access Journals (Sweden)

    Parinaz Taheri

    2012-12-01

    Full Text Available A bacteriocin-like inhibitory substance producing Lactococcus lactis subsp lactis strain, ST1, isolated from goat milk of Iranian origin and with broad spectrum of activity and desirable technical properties was used for evaluating some futures of bacteriocin inhibitory activity. Cell growth and bacteriocin production studies were carried out in MRS medium incubated statically under uncontrolled pH condition. The antibacterial activity presented a primary metabolite pattern and showed a rapid decrease at the stationary phase. Microaerobiosis and capnophily growth conditions resulted in higher bacteriocin production while aerobiosis showed negative effect on both cell growth and bacteriocin production. Bacteriocin production, on the other hand, was favored in MRS broth (pH; 6.5 inoculated with 0.1 ml l-1 fresh culture when incubation was carried out at 30 °C. This indicated that the conditions resulted in higher levels of growth were frequently favoring bacteriocin production by ST1 as well. Decrease in activity, at the stationary growth phase, was much pronounced in favored growth condition. Nutrient depletion, deferent effect of low pH on bacteriocin production and/or protein degradation seemed more responsible for this phenomenon. The study also provided further data on new method for bacteriocin release from the cell wall of producer. It was clearly shown that both heating and ultrasound shock for 5 min at pH 2 could increase bacteriocin activity significantly. The release was more pronounced in the presence of 0.5% Tween80.

  18. Antimicrobial activity of the Nisin Z producer Lactococcus lactis subsp. lactis Lc08 against Listeria monocytogenes in skim milk

    Directory of Open Access Journals (Sweden)

    L.M. Perin

    2013-10-01

    Full Text Available The presented study aimed to verify the effect of different pH values, enzyme solutions and heat treatments on the antimicrobial activity of the bacteriocinogenic strain Lactococcus lactis subsp. lactis Lc08 and to test their antimicrobial activity against Listeria monocytogenes in reconstituted skim milk at refrigeration temperatures. This strain was previously described as a nisin Z producer and capable of inhibiting L. monocytogenes growth in in vitro tests. The antimicrobial activity of the bacteriocin cell-free supernatant of Lc08 was sensitive to enzyme treatments (except papain. The pH values and heating (65ºC for 30min, 75ºC for 15s had no apparent effect on the antimicrobial activity of the bacteriocin produced by Lc08. Only treatment at autoclave conditions result in loss of their antimicrobial activity. Lc08 presented antimicrobial activity against L. monocytogenes in the milk system after 12h at 25ºC. No effect was found at 7ºC. The results show the application viability of the Lc08 in food systems as a biopreservative against L. monocytogenes.

  19. Molecular Cloning and Sequence Analysis of the X-Prolyl Dipeptidyl Aminopeptidase Gene From Lactococcus lactis subsp. cremoris

    NARCIS (Netherlands)

    Mayo, Baltasar; Kok, Jan; Venema, Konraad; Bockelmann, Wilhelm; Teuber, Michael; Reinke, Heinz; Venema, Gerhardus

    1991-01-01

    Lactococcus lactis subsp. cremoris P8-2-47 contains an X-prolyl dipeptidyl aminopeptidase (X-PDAP; EC 3.4.14.5). A mixed-oligonucleotide probe prepared on the basis of the N-terminal amino acid sequence of the purified protein was made and used to screen a partial chromosomal DNA bank in Escherichia

  20. Complete Genome Sequence of Lactococcus lactis Strain AI06, an Endophyte of the Amazonian Açaí Palm

    OpenAIRE

    McCulloch, John Anthony; de Oliveira, Viviane Matoso; de Almeida Pina, André Vicioli; Pérez-Chaparro, Paula Juliana; Almeida, Lara Mendes; de Vasconcelos, Janaina Mota; de Oliveira, Layanna Freitas; da Silva, Daisy Elaine Andrade; Rogez, Hervé Louis Ghislain; CRETENET, Marina; Mamizuka, Elsa Masae; Nunes, Marcio Roberto Teixeira

    2014-01-01

    We report the genome, in a single chromosome, of Lactococcus lactis strain AI06, isolated from the mesocarp of the açaí fruit (Euterpe oleracea) in eastern Amazonia, Brazil. This strain is an endophyte of the açaí palm and also a component of the microbiota of the edible food product.

  1. The carB gene encoding the large subunit of carbamoylphosphate synthetase from Lactococcus lactis is transcribed monocistronically

    DEFF Research Database (Denmark)

    Martinussen, Jan; Hammer, Karin

    1998-01-01

    The biosynthesis of carbamoylphosphate is catalysed by the heterodimeric enzyme carbamoylphosphate synthetase (CPSase). The genes encoding the two subunits in procaryotes are normally transcribed as an operon, whereas in Lactococcus lactis, the gene encoding the large subunit (carB) is shown to b...

  2. Complete Genome Sequence of Lactococcus lactis Strain AI06, an Endophyte of the Amazonian Açaí Palm.

    Science.gov (United States)

    McCulloch, John Anthony; de Oliveira, Viviane Matoso; de Almeida Pina, André Vicioli; Pérez-Chaparro, Paula Juliana; de Almeida, Lara Mendes; de Vasconcelos, Janaina Mota; de Oliveira, Layanna Freitas; da Silva, Daisy Elaine Andrade; Rogez, Hervé Louis Ghislain; Cretenet, Marina; Mamizuka, Elsa Masae; Nunes, Marcio Roberto Teixeira

    2014-01-01

    We report the genome, in a single chromosome, of Lactococcus lactis strain AI06, isolated from the mesocarp of the açaí fruit (Euterpe oleracea) in eastern Amazonia, Brazil. This strain is an endophyte of the açaí palm and also a component of the microbiota of the edible food product. PMID:25414513

  3. Stability of active prophages in industrial Lactococcus lactis strains in the presence of heat, acid, osmotic, oxidative and antibiotic stressors.

    Science.gov (United States)

    Ho, Chun-Hoong; Stanton-Cook, Mitchell; Beatson, Scott A; Bansal, Nidhi; Turner, Mark S

    2016-03-01

    Lactococcus lactis is a starter bacterium commonly used in cheese making where it has an important role in acid-mediated curd formation as well as the development of flavour compounds. Industrial L. lactis strains can harbour one or more inducible prophages which when induced can affect cell growth and possibly lead to cell lysis. This is undesirable during growth and fermentation, but can beneficially lead to faster release of enzymes during cheese ripening. Lactococci can encounter multiple stress inducing conditions during the production of cheese, such as low and high temperatures, low pH, high osmotic pressure and long-term incubation. In this study, we tested the effect of these industrial stressors on prophage induction in two cheese making L. lactis subsp. cremoris strains (ASCC890049 and ASCC890310) as well as the laboratory strain L. lactis MG1363. Firstly, in order to identify inducible prophages in these strains we exposed them to the prophage inducing chemical mitomycin C (MMC) for 1 and 2h and then subjected the total genomic DNA to next-generation Illumina sequencing. Mapping of sequence reads back to the genome sequences revealed regions which contained a much higher fold coverage indicating DNA replication. These regions were amplified by up to 332-fold per cell (relative to the control tufA gene) and were identified as having similarities to different subgroups of P335 phages including MG-5, TP901-1, ul36.k1, bIL286, TP712 and BK5-T. Next, quantitative PCR was used to confirm the strong induction of prophages by MMC and then determine the copy number of the inducible prophages following exposure to various growth inhibitory levels of HCl, lactic acid, high temperature, NaCl, hydrogen peroxide and bacitracin. With the exception of a slight induction (2 to 4-fold) with hydrogen peroxide and long-term incubation after 21days in one industrial strain, none of the other stressors induced prophage DNA replication. These findings show that the repression

  4. Heterologous protein secretion in Lactococcus lactis: a novel antigen delivery system

    Directory of Open Access Journals (Sweden)

    Langella P.

    1999-01-01

    Full Text Available Lactic acid bacteria (LAB are Gram-positive bacteria and are generally regarded as safe (GRAS organisms. Therefore, LAB could be used for heterologous protein secretion and they are good potential candidates as antigen delivery vehicles. To develop such live vaccines, a better control of protein secretion is required. We developed an efficient secretion system in the model LAB, Lactococcus lactis. Staphylococcal nuclease (Nuc was used as the reporter protein. We first observed that the quantity of secreted Nuc correlated with the copy number of the cloning vector. The nuc gene was cloned on a high-copy number cloning vector and no perturbation of the metabolism of the secreting strain was observed. Replacement of nuc native promoter by a strong lactococcal one led to a significant increase of nuc expression. Secretion efficiency (SE of Nuc in L. lactis was low, i.e., only 60% of the synthesized Nuc was secreted. Insertion of a synthetic propeptide between the signal peptide and the mature moiety of Nuc increased the SE of Nuc. On the basis of these results, we developed a secretion system and we applied it to the construction of an L. lactis strain which secretes a bovine coronavirus (BCV epitope-protein fusion (BCV-Nuc. BCV-Nuc was recognized by both anti-BCV and anti-Nuc antibodies. Secretion of this antigenic fusion is the first step towards the development of a novel antigen delivery system based on LAB-secreting strains.

  5. Transcriptomic profile of aguR deletion mutant of Lactococcus lactis subsp. cremoris CECT 8666.

    Science.gov (United States)

    Del Rio, Beatriz; Linares, Daniel M; Redruello, Begoña; Martin, Maria Cruz; Fernandez, Maria; de Jong, Anne; Kuipers, Oscar P; Ladero, Victor; Alvarez, Miguel A

    2015-12-01

    Lactococcus lactis subsp. cremoris CECT 8666 (formerly GE2-14) is a dairy strain that catabolizes agmatine (a decarboxylated derivative of arginine) into the biogenic amine putrescine by the agmatine deiminase (AGDI) pathway [1]. The AGDI cluster of L. lactis is composed by five genes aguR, aguB, aguD, aguA and aguC. The last four genes are responsible for the deamination of agmatine to putrescine and are co-transcribed as a single policistronic mRNA forming the catabolic operon aguBDAC[1]. aguR encodes a transmembrane protein that functions as a one-component signal transduction system that senses the agmatine concentration of the medium and accordingly regulates the transcription of aguBDAC[2], which is also transcriptionally regulated by carbon catabolic repression (CCR) via glucose, but not by other sugars such as lactose and galactose [1], [3]. Here we report the transcriptional profiling of the aguR gene deletion mutant (L. lactis subsp. cremoris CECT 8666 ∆aguR) [2] compared to the wild type strain, both grown in M17 medium with galactose as carbon source and supplemented with agmatine. The transcriptional profiling data of AguR-regulated genes were deposited in the Gene Expression Omnibus (GEO) database under accession no. GSE59514. PMID:26697381

  6. Phosphoglycerate Mutase Is a Highly Efficient Enzyme without Flux Control in Lactococcus lactis

    DEFF Research Database (Denmark)

    Solem, Christian; Petranovic, D.; Købmann, Brian;

    2010-01-01

    The glycolytic enzyme phosphoglycerate mutase (PGM), which catalyzes the conversion of 3-phosphoglycerate to 2-phosphoglycerate, was examined in Lactococcus lactis with respect to its function, kinetics and glycolytic flux control. A library of strains with PGM activities ranging between 15-465% of....... lactis PGM was dependent on 2,3-bisphosphoglyceric acid for activity, which showed that the enzyme is of the dPGM type in accordance with its predicted homology to dPGM enzymes from other organisms. In conclusion, PGM from L. lactis is a highly efficient catalyst, which partially explains why this enzyme...... at highly reduced PGM activities. At the wild-type level PGM operated very far from V-max. Consequently, in a strain with only 15% PGM activity, the catalytic rate of PGM was almost six times higher than in the wildtype. K-m of PGM for 3-phosphoglycerate was 1.0 m M and k(cat) was 3,200 s(-1). The L...

  7. Enhance nisin yield via improving acid-tolerant capability of Lactococcus lactis F44.

    Science.gov (United States)

    Zhang, Jian; Caiyin, Qinggele; Feng, Wenjing; Zhao, Xiuli; Qiao, Bin; Zhao, Guangrong; Qiao, Jianjun

    2016-01-01

    Traditionally, nisin was produced industrially by using Lactococcus lactis in the neutral fermentation process. However, nisin showed higher activity in the acidic environment. How to balance the pH value for bacterial normal growth and nisin activity might be the key problem. In this study, 17 acid-tolerant genes and 6 lactic acid synthetic genes were introduced in L. lactis F44, respectively. Comparing to the 2810 IU/mL nisin yield of the original strain F44, the nisin titer of the engineered strains over-expressing hdeAB, ldh and murG, increased to 3850, 3979 and 4377 IU/mL, respectively. These engineered strains showed more stable intracellular pH value during the fermentation process. Improvement of lactate production could partly provide the extra energy for the expression of acid tolerance genes during growth. Co-overexpression of hdeAB, murG, and ldh(Z) in strain F44 resulted in the nisin titer of 4913 IU/mL. The engineered strain (ABGL) could grow on plates with pH 4.2, comparing to the surviving pH 4.6 of strain F44. The fed-batch fermentation showed nisin titer of the co-expression L. lactis strain could reach 5563 IU/mL with lower pH condition and longer cultivation time. This work provides a novel strategy of constructing robust strains for use in industry process. PMID:27306587

  8. Coculture-inducible bacteriocin biosynthesis of different probiotic strains by dairy starter culture Lactococcus lactis

    Directory of Open Access Journals (Sweden)

    Blaženka Kos

    2011-12-01

    Full Text Available Bacteriocins produced by probiotic strains effectively contribute to colonization ability of probiotic strains and facilitate their establishment in the competitive gut environment and also protect the gut from gastrointestinal pathogens. Moreover, bacteriocins have received considerable attention due to their potential application as biopreservatives, especially in dairy industry. Hence, the objective of this research was to investigate antimicrobial activity of probiotic strains Lactobacillus helveticus M92, Lactobacillus plantarum L4 and Enterococcus faecium L3, with special focus on their bacteriocinogenic activity directed towards representatives of the same or related bacterial species, and towards distant microorganisms including potential food contaminants or causative agents of gut infections. In order to induce bacteriocin production, probiotic cells were cocultivated with Lactococcus lactis subsp. lactis LMG 9450, one of the most important starter cultures in cheese production. The presence of bacteriocin coding genes was investigated by PCR amplification with sequence-specific primers for helveticin and was confirmed for probiotic strain L. helveticus M92. All examined probiotic strains have shown bacteriocinogenic activity against Staphylococcus aureus 3048, Staphylococcus aureus K-144, Escherichia coli 3014, Salmonella enterica serovar Typhimurium FP1, Bacillus subtilis ATCC 6633, Bacillus cereus TM2, which is an important functional treat of probiotic strains significant in competitive exclusion mechanism which provides selective advantage of probiotic strains against undesirable microorganisms in gastrointestinal tract of the host. According to obtained results, living cells of starter culture Lc. lactis subsp. lactis LMG 9450 induced bacteriocin production by examined probiotic strains but starter culture itself was not sensitive to bacteriocin activity.

  9. Cold shock proteins of Lactococcus lactis MG1363 are involved in cryoprotection and in the production of cold-induced proteins.

    Science.gov (United States)

    Wouters, J A; Frenkiel, H; de Vos, W M; Kuipers, O P; Abee, T

    2001-11-01

    Members of the group of 7-kDa cold-shock proteins (CSPs) are the proteins with the highest level of induction upon cold shock in the lactic acid bacterium Lactococcus lactis MG1363. By using double-crossover recombination, two L. lactis strains were generated in which genes encoding CSPs are disrupted: L. lactis NZ9000 Delta AB lacks the tandemly orientated cspA and cspB genes, and NZ9000 Delta ABE lacks cspA, cspB, and cspE. Both strains showed no differences in growth at normal and at low temperatures compared to that of the wild-type strain, L. lactis NZ9000. Two-dimensional gel electrophoresis showed that upon disruption of the cspAB genes, the production of remaining CspE at low temperature increased, and upon disruption of cspA, cspB, and cspE, the production of CspD at normal growth temperatures increased. Northern blot analysis showed that control is most likely at the transcriptional level. Furthermore, it was established by a proteomics approach that some (non-7-kDa) cold-induced proteins (CIPs) are not cold induced in the csp-lacking strains, among others the histon-like protein HslA and the signal transduction protein LlrC. This supports earlier observations (J. A. Wouters, M. Mailhes, F. M. Rombouts, W. M. De Vos, O. P. Kuipers, and T. Abee, Appl. Environ. Microbiol. 66:3756-3763, 2000). that the CSPs of L. lactis might be directly involved in the production of some CIPs upon low-temperature exposure. Remarkably, the adaptive response to freezing by prior exposure to 10 degrees C was significantly reduced in strain NZ9000 Delta ABE but not in strain NZ9000 Delta AB compared to results with wild-type strain NZ9000, indicating a notable involvement of CspE in cryoprotection. PMID:11679342

  10. Mdt(A), a New Efflux Protein Conferring Multiple Antibiotic Resistance in Lactococcus lactis and Escherichia coli

    Science.gov (United States)

    Perreten, Vincent; Schwarz, Franziska V.; Teuber, Michael; Levy, Stuart B.

    2001-01-01

    The mdt(A) gene, previously designated mef214, from Lactococcus lactis subsp. lactis plasmid pK214 encodes a protein [Mdt(A) (multiple drug transporter)] with 12 putative transmembrane segments (TMS) that contain typical motifs conserved among the efflux proteins of the major facilitator superfamily. However, it also has two C-motifs (conserved in the fifth TMS of the antiporters) and a putative ATP-binding site. Expression of the cloned mdt(A) gene decreased susceptibility to macrolides, lincosamides, streptogramins, and tetracyclines in L. lactis and Escherichia coli, but not in Enterococcus faecalis or in Staphylococcus aureus. Glucose-dependent efflux of erythromycin and tetracycline was demonstrated in L. lactis and in E. coli. PMID:11257023

  11. ClpE from Lactococcus lactis promotes repression of CtsR-dependent gene expression

    DEFF Research Database (Denmark)

    Varmanen, P.; Vogensen, F.K.; Hammer, Karin;

    2003-01-01

    The heat shock response in bacterial cells is characterized by rapid induction of heat shock protein expression, followed by an adaptation period during which heat shock protein synthesis decreases to a new steady-state level. In this study we found that after a shift to a high temperature the Clp...... ATPase (ClpE) in Lactococcus lactis is required for such a decrease in expression of a gene negatively regulated by the heat shock regulator (CtsR). Northern blot analysis showed that while a shift to a high temperature in wild-type cells resulted in a temporal increase followed by a decrease in......R homologue in Bacillus subtilis. Thus, our data point to a regulatory role of ClpE in turning off clpP gene expression following temporal heat shock induction, and we propose that this effect is mediated through CtsR....

  12. Mdt(A), a New Efflux Protein Conferring Multiple Antibiotic Resistance in Lactococcus lactis and Escherichia coli

    OpenAIRE

    Perreten, Vincent; Schwarz, Franziska V.; Teuber, Michael; Levy, Stuart B.

    2001-01-01

    The mdt(A) gene, previously designated mef214, from Lactococcus lactis subsp. lactis plasmid pK214 encodes a protein [Mdt(A) (multiple drug transporter)] with 12 putative transmembrane segments (TMS) that contain typical motifs conserved among the efflux proteins of the major facilitator superfamily. However, it also has two C-motifs (conserved in the fifth TMS of the antiporters) and a putative ATP-binding site. Expression of the cloned mdt(A) gene decreased susceptibility to macrolides, lin...

  13. Glucose metabolism in Lactococcus lactis MG1363 under different aeration conditions: Requirement of acetate to sustain growth under microaerobic conditions

    DEFF Research Database (Denmark)

    Nordkvist, Mikkel; Jensen, N.B.S.; Villadsen, John

    2003-01-01

    Lactococcus lactis subsp. lactis MG1363 was grown in batch cultures on a defined medium with glucose as the energy source under different aeration conditions, namely, anaerobic conditions, aerobic conditions, and microaerobic conditions with a dissolved oxygen tension of 5% (when saturation with...... air was used as the reference). The maximum specific growth rate was high (0.78 to 0.91 h(-1)) under all aeration conditions but decreased with increasing aeration, and more than 90% of the glucose was converted to lactate. However, a shift in by-product formation was observed. Increasing aeration...

  14. Exploring optimization parameters to increase ssDNA recombineering in Lactococcus lactis and Lactobacillus reuteri.

    Science.gov (United States)

    Van Pijkeren, Jan-Peter; Neoh, Kar Mun; Sirias, Denise; Findley, Anthony S; Britton, Robert A

    2012-01-01

    Single-stranded DNA (ssDNA) recombineering is a technology which is used to make subtle changes in the chromosome of several bacterial genera. Cells which express a single-stranded DNA binding protein (RecT or Bet) are transformed with an oligonucleotide which is incorporated via an annealing and replication-dependent mechanism. By in silico analysis we identified ssDNA binding protein homologs in the genus Lactobacillus and Lactococcus lactis. To assess whether we could further improve the recombineering efficiency in Lactobacillus reuteri ATCC PTA 6475 we expressed several RecT homologs in this strain. RecT derived from Enterococcus faecalis CRMEN 19 yielded comparable efficiencies compared with a native RecT protein, but none of the other proteins further increased the recombineering efficiency. We successfully improved recombineering efficiency 10-fold in L. lactis by increasing oligonucleotide concentration combined with the use of oligonucleotides containing phosphorothioate-linkages (PTOs). Surprisingly, neither increased oligonucleotide concentration nor PTO linkages enhanced recombineering in L. reuteri 6475. To emphasize the utility of this technology in improving probiotic features we modified six bases in a transcriptional regulatory element region of the pdu-operon of L. reuteri 6475, yielding a 3-fold increase in the production of the antimicrobial compound reuterin. Directed genetic modification of lactic acid bacteria through ssDNA recombineering will simplify strain improvement in a way that, when mutating a single base, is genetically indistinguishable from strains obtained through directed evolution. PMID:22750793

  15. Transcriptome profiling of Lactococcus lactis subsp. cremoris CECT 8666 in response to agmatine.

    Science.gov (United States)

    Del Rio, Beatriz; Redruello, Begoña; Martin, M Cruz; Fernandez, Maria; de Jong, Anne; Kuipers, Oscar P; Ladero, Victor; Alvarez, Miguel A

    2016-03-01

    The dairy strain Lactococcus lactis subsp. cremoris CECT 8666 (formerly GE2-14) synthesizes the biogenic amine putrescine from agmatine via the agmatine deiminase (AGDI) pathway [1]. The AGDI cluster of L. lactis is composed by five genes aguR, aguB, aguD, aguA and aguC. The last four genes are co-transcribed as a single policistronic mRNA forming the catabolic operon aguBDAC, which encodes the proteins necessary for agmatine uptake and its conversion into putrescine [1], [2]. The first gene of the cluster, aguR, encodes a transmembrane protein that functions as a one-component signal transduction system that senses the agmatine concentration of the medium and accordingly regulates the transcription of aguBDAC[2]. The catabolic operon aguBDAC is transcriptionally activated by agmatine [2] and transcriptionally regulated by carbon catabolite repression (CCR) via glucose, but not by other sugars such as lactose or galactose [1], [3]. On the contrary, the transcription of the aguR regulatory gene is not subject to CCR regulation [1], [3] nor is regulated by agmatine [2]. In this study we report the transcriptional profiling of L. lactis subsp. cremoris CECT 8666 grown in M17 medium with galactose (GalM17) as carbon source and supplemented with agmatine, compared to that of the strain grown in the same culture medium without agmatine. The transcriptional profiling data of agmatine-regulated genes were deposited in the Gene Expression Omnibus (GEO) database under Accession no. GSE74808. PMID:26981381

  16. Transcriptome profiling of Lactococcus lactis subsp. cremoris CECT 8666 in response to agmatine

    Directory of Open Access Journals (Sweden)

    Beatriz del Rio

    2016-03-01

    Full Text Available The dairy strain Lactococcus lactis subsp. cremoris CECT 8666 (formerly GE2-14 synthesizes the biogenic amine putrescine from agmatine via the agmatine deiminase (AGDI pathway [1]. The AGDI cluster of L. lactis is composed by five genes aguR, aguB, aguD, aguA and aguC. The last four genes are co-transcribed as a single policistronic mRNA forming the catabolic operon aguBDAC, which encodes the proteins necessary for agmatine uptake and its conversion into putrescine [1,2]. The first gene of the cluster, aguR, encodes a transmembrane protein that functions as a one-component signal transduction system that senses the agmatine concentration of the medium and accordingly regulates the transcription of aguBDAC [2]. The catabolic operon aguBDAC is transcriptionally activated by agmatine [2] and transcriptionally regulated by carbon catabolite repression (CCR via glucose, but not by other sugars such as lactose or galactose [1,3]. On the contrary, the transcription of the aguR regulatory gene is not subject to CCR regulation [1,3] nor is regulated by agmatine [2]. In this study we report the transcriptional profiling of L. lactis subsp. cremoris CECT 8666 grown in M17 medium with galactose (GalM17 as carbon source and supplemented with agmatine, compared to that of the strain grown in the same culture medium without agmatine. The transcriptional profiling data of agmatine-regulated genes were deposited in the Gene Expression Omnibus (GEO database under Accession no. GSE74808.

  17. Characterization of the Lactococcus lactis lactose operon promoter: contribution of flanking sequences and LacR repressor to promoter activity.

    OpenAIRE

    van Rooijen, R J; Gasson, M. J.; de Vos, W M

    1992-01-01

    We determined the location, activity, and regulation of the promoter of the Lactococcus lactis 8-kb lactose operon (lacABCDFEGX), which encodes the enzymes of the lactose phosphotransferase system and the tagatose 6-phosphate pathway. The lac promoter sequence corresponds closely to the consensus promoter described for gram-positive bacteria and is located in a back-to-back configuration with the promoter of the divergently transcribed lacR gene, which encodes the LacR repressor. The transcri...

  18. Transcriptional Regulation and Evolution of Lactose Genes in the Galactose-Lactose Operon of Lactococcus lactis NCDO2054

    OpenAIRE

    Vaughan, Elaine E.; Pridmore, R. David; Mollet, Beat

    1998-01-01

    The genetics of lactose utilization within the slow-lactose-fermenting Lactococcus lactis strain NCDO2054 was studied with respect to the organization, expression, and evolution of the lac genes. Initially the β-galactosidase gene (lacZ) was cloned by complementation of an Escherichia coli mutant on a 7-kb HpaI fragment. Nucleotide sequence analysis of the complete fragment revealed part of a gal-lac operon, and the genes were characterized by inactivation and complementation analyses and in ...

  19. Expression of a Heterologous Glutamate Dehydrogenase Gene in Lactococcus lactis Highly Improves the Conversion of Amino Acids to Aroma Compounds

    OpenAIRE

    Rijnen, Liesbeth; Courtin, Pascal; Gripon, Jean-Claude; Yvon, Mireille

    2000-01-01

    The first step of amino acid degradation in lactococci is a transamination, which requires an α-keto acid as the amino group acceptor. We have previously shown that the level of available α-keto acid in semihard cheese is the first limiting factor for conversion of amino acids to aroma compounds, since aroma formation is greatly enhanced by adding α-ketoglutarate to cheese curd. In this study we introduced a heterologous catabolic glutamate dehydrogenase (GDH) gene into Lactococcus lactis so ...

  20. Molecular and Functional Analyses of the metC Gene of Lactococcus lactis, Encoding Cystathionine β-Lyase

    OpenAIRE

    Fernández, María; Doesburg, Wim van; Rutten, Ger A.M.; Marugg, Joey D.; Alting, Arno C.; van Kranenburg, Richard; Oscar P. Kuipers

    2000-01-01

    The enzymatic degradation of amino acids in cheese is believed to generate aroma compounds and therefore to be essential for flavor development. Cystathionine β-lyase (CBL) can convert cystathionine to homocysteine but is also able to catalyze an α,γ elimination. With methionine as a substrate, it produces volatile sulfur compounds which are important for flavor formation in Gouda cheese. The metC gene, which encodes CBL, was cloned from the Lactococcus lactis model strain MG1363 and from str...

  1. The protective effect of recombinant Lactococcus lactis oral vaccine on a Clostridium difficile-infected animal model

    OpenAIRE

    Yang, Xiao-qiang; Zhao, Ya-Gang; Chen, Xue-Qing; Jiang, Bo; SUN, DA-YONG

    2013-01-01

    Background Oral immunization with vaccines may be an effective strategy for prevention of Clostridium difficile infection (CDI). However, application of previously developed vaccines for preventing CDI has been limited due to various reasons. Here, we developed a recombinant Lactococcus lactis oral vaccine and evaluated its effect on a C. difficile-infected animal model established in golden hamsters in attempt to provide an alternative strategy for CDI prevention. Methods Recombinant L. lact...

  2. Reassessing the Role of Staphylococcus aureus Clumping Factor and Fibronectin-Binding Protein by Expression in Lactococcus lactis

    OpenAIRE

    Que, Yok-Ai; François, Patrice; Haefliger, Jacques-Antoine; Entenza, José-Manuel; Vaudaux, Pierre; Moreillon, Philippe

    2001-01-01

    Since Staphylococcus aureus expresses multiple pathogenic factors, studying their individual roles in single-gene-knockout mutants is difficult. To circumvent this problem, S. aureus clumping factor A (clfA) and fibronectin-binding protein A (fnbA) genes were constitutively expressed in poorly pathogenic Lactococcus lactis using the recently described pOri23 vector. The recombinant organisms were tested in vitro for their adherence to immobilized fibrinogen and fibronectin and in vivo for the...

  3. Multi-stress resistance in Lactococcus lactis is actually escape from purine-induced stress sensitivity

    DEFF Research Database (Denmark)

    Ryssel, Mia; Hviid, Anne-Mette Meisner; Dawish, Mohamed S.;

    2014-01-01

    to the acid-stress medium increased the stress sensitivity of L. lactis MG1363. It is also shown that high intracellular guanine nucleotide pools confer increased sensitivity to high temperatures, thus showing that it is indeed a multi-stress phenotype. Our analysis suggests that an increased level......Multi-stress resistance is a widely documented and fascinating phenotype of lactococci where single mutations, preferentially in genes involved in nucleotide metabolism and phosphate uptake, result in elevated tolerance to multiple stresses simultaneously. In this report, we have analysed the...... metabolic basis behind this multi-stress-resistance phenotype in Lactococcus lactis subsp. cremoris MG1363 using acid stress as a model of multi-stress resistance. Surprisingly, we found that L. lactis MG1363 is fully resistant to pH 3.0 in the chemically defined SA medium, contrary to its sensitivity in...

  4. Evaluation of Lactococcus lactis Isolates from Nondairy Sources with Potential Dairy Applications Reveals Extensive Phenotype-Genotype Disparity and Implications for a Revised Species.

    Science.gov (United States)

    Cavanagh, Daniel; Casey, Aidan; Altermann, Eric; Cotter, Paul D; Fitzgerald, Gerald F; McAuliffe, Olivia

    2015-06-15

    Lactococcus lactis is predominantly associated with dairy fermentations, but evidence suggests that the domesticated organism originated from a plant niche. L. lactis possesses an unusual taxonomic structure whereby strain phenotypes and genotypes often do not correlate, which in turn has led to confusion in L. lactis classification. A bank of L. lactis strains was isolated from various nondairy niches (grass, vegetables, and bovine rumen) and was further characterized on the basis of key technological traits, including growth in milk and key enzyme activities. Phenotypic analysis revealed all strains from nondairy sources to possess an L. lactis subsp. lactis phenotype (lactis phenotype); however, seven of these strains possessed an L. lactis subsp. cremoris genotype (cremoris genotype), determined by two separate PCR assays. Multilocus sequence typing (MLST) showed that strains with lactis and cremoris genotypes clustered together regardless of habitat, but it highlighted the increased diversity that exists among "wild" strains. Calculation of average nucleotide identity (ANI) and tetranucleotide frequency correlation coefficients (TETRA), using the JSpecies software tool, revealed that L. lactis subsp. cremoris and L. lactis subsp. lactis differ in ANI values by ∼14%, below the threshold set for species circumscription. Further analysis of strain TIFN3 and strains from nonindustrial backgrounds revealed TETRA values of revision of L. lactis taxonomy. PMID:25841018

  5. Plasmid elimination of Lactococcus lactis%乳酸乳球菌的质粒消除

    Institute of Scientific and Technical Information of China (English)

    柳国霞; 范丽平; 霍贵成

    2009-01-01

    质粒消除是签定质粒和获得无质粒菌株的重要方法,是乳酸菌进行遗传学改造所需的一项重要技术.试验采用高温和消除剂结合的方法,对乳酸乳球菌镉抗性菌株进行质粒消除,探讨温度、消除剂吖啶橙的用量和作用时间对乳酸乳球菌镉抗性质粒消除的影响.结果表明,39℃高温可以质粒消除,而37和41℃均无此效果;独自吖叮橙作用未获得质粒消除菌株;39℃高温-吖啶橙同时作用比高温-吖啶橙交替作用消除率高,而39℃高温-20 μg·mL-1吖啶橙共同作用12 d,消除率可达98%.根据消除结果,以疑似功能性质粒为模板,进行PCR扩增,获得预期片段,进一步证实了其功能.%Plasmid elimination is a key method of plasmid identificaton and obtaining non-plasmid strain, and it is an important technology which was needed by genetics transformation in lactic acid bacteria. High temperature and the elimination agent were combined by plasmid elimination for a cadmium-resistant Lactococcus lactis strains, the amount and the time by using temperature and eUminaton agent acridine orange (AO) were approached on the effect of cadmium-resistant Lactococcus lactis plasmid. The results showed that 39℃ high temperature could eliminate the plasmid, but 37 and 41℃ had no effects. Plasmid elimination strain was not obtained by using AO alone, the elimination rate by the method of both high temperature and AO at the same time was higher than that of by interchanging between high temperature and AO. The combined effect of 39℃ temperature and 20 μg·mL-1 AO for 12 days was significant, the elimination rate was as high as 98%. According to the results, PCR amplification was based on the suspected functional plasmid as a template, achieved the desired fragment, and further confirmed its functions.

  6. Reduced binding of the endolysin LysTP712 to Lactococcus lactis ΔftsH contributes to phage resistance

    Directory of Open Access Journals (Sweden)

    CLARA eROCES

    2016-02-01

    Full Text Available Absence of the membrane protease FtsH in Lactococcus lactis hinders release of the bacteriophage TP712. In this work we have analysed the mechanism responsible for the non-lytic phenotype of L. lactis ΔftsH after phage infection. The lytic cassette of TP712 contains a putative antiholin-pinholin system and a modular endolysin (LysTP712. Inducible expression of the holin gene demonstrated the presence of a dual start motif which is functional in both wildtype and L. lactis ΔftsH cells. Moreover, simulating holin activity with ionophores accelerated lysis of wildtype cells but not L. lactis ΔftsH cells, suggesting inhibition of the endolysin rather than a role of FtsH in holin activation. However, zymograms revealed the synthesis of an active endolysin in both wildtype and L. lactis ΔftsH TP712 lysogens. A reporter protein was generated by fusing the cell wall binding domain of LysTP712 to the fluorescent mCherry protein. Binding of this reporter protein took place at the septa of both wildtype and L. lactis ΔftsH cells as shown by fluorescence microscopy. Nonetheless, fluorescence spectroscopy demonstrated that mutant cells bound 40 % less protein. In conclusion, the non-lytic phenotype of L. lactis ΔftsH is not due to direct action of the FtsH protease on the phage lytic proteins but rather to a putative function of FtsH in modulating the architecture of the L. lactis cell envelope that contributes to a lower affinity of the phage endolysin to its substrate and, likely to its catalytic activity.

  7. Reduced Binding of the Endolysin LysTP712 to Lactococcus lactis ΔftsH Contributes to Phage Resistance.

    Science.gov (United States)

    Roces, Clara; Campelo, Ana B; Escobedo, Susana; Wegmann, Udo; García, Pilar; Rodríguez, Ana; Martínez, Beatriz

    2016-01-01

    Absence of the membrane protease FtsH in Lactococcus lactis hinders release of the bacteriophage TP712. In this work we have analyzed the mechanism responsible for the non-lytic phenotype of L. lactis ΔftsH after phage infection. The lytic cassette of TP712 contains a putative antiholin-pinholin system and a modular endolysin (LysTP712). Inducible expression of the holin gene demonstrated the presence of a dual start motif which is functional in both wildtype and L. lactis ΔftsH cells. Moreover, simulating holin activity with ionophores accelerated lysis of wildtype cells but not L. lactis ΔftsH cells, suggesting inhibition of the endolysin rather than a role of FtsH in holin activation. However, zymograms revealed the synthesis of an active endolysin in both wildtype and L. lactis ΔftsH TP712 lysogens. A reporter protein was generated by fusing the cell wall binding domain of LysTP712 to the fluorescent mCherry protein. Binding of this reporter protein took place at the septa of both wildtype and L. lactis ΔftsH cells as shown by fluorescence microscopy. Nonetheless, fluorescence spectroscopy demonstrated that mutant cells bound 40% less protein. In conclusion, the non-lytic phenotype of L. lactis ΔftsH is not due to direct action of the FtsH protease on the phage lytic proteins but rather to a putative function of FtsH in modulating the architecture of the L. lactis cell envelope that results in a lower affinity of the phage endolysin to its substrate. PMID:26904011

  8. Reduced Binding of the Endolysin LysTP712 to Lactococcus lactis ΔftsH Contributes to Phage Resistance

    Science.gov (United States)

    Roces, Clara; Campelo, Ana B.; Escobedo, Susana; Wegmann, Udo; García, Pilar; Rodríguez, Ana; Martínez, Beatriz

    2016-01-01

    Absence of the membrane protease FtsH in Lactococcus lactis hinders release of the bacteriophage TP712. In this work we have analyzed the mechanism responsible for the non-lytic phenotype of L. lactis ΔftsH after phage infection. The lytic cassette of TP712 contains a putative antiholin–pinholin system and a modular endolysin (LysTP712). Inducible expression of the holin gene demonstrated the presence of a dual start motif which is functional in both wildtype and L. lactis ΔftsH cells. Moreover, simulating holin activity with ionophores accelerated lysis of wildtype cells but not L. lactis ΔftsH cells, suggesting inhibition of the endolysin rather than a role of FtsH in holin activation. However, zymograms revealed the synthesis of an active endolysin in both wildtype and L. lactis ΔftsH TP712 lysogens. A reporter protein was generated by fusing the cell wall binding domain of LysTP712 to the fluorescent mCherry protein. Binding of this reporter protein took place at the septa of both wildtype and L. lactis ΔftsH cells as shown by fluorescence microscopy. Nonetheless, fluorescence spectroscopy demonstrated that mutant cells bound 40% less protein. In conclusion, the non-lytic phenotype of L. lactis ΔftsH is not due to direct action of the FtsH protease on the phage lytic proteins but rather to a putative function of FtsH in modulating the architecture of the L. lactis cell envelope that results in a lower affinity of the phage endolysin to its substrate. PMID:26904011

  9. GABA Production in Lactococcus lactis Is Enhanced by Arginine and Co-addition of Malate.

    Science.gov (United States)

    Laroute, Valérie; Yasaro, Chonthicha; Narin, Waranya; Mazzoli, Roberto; Pessione, Enrica; Cocaign-Bousquet, Muriel; Loubière, Pascal

    2016-01-01

    Lactococcus lactis NCDO 2118 was previously selected for its ability to decarboxylate glutamate to γ-aminobutyric acid (GABA), an interesting nutritional supplement able to improve mood and relaxation. Amino acid decarboxylation is generally considered as among the biochemical systems allowing lactic acid bacteria to counteracting acidic stress and obtaining metabolic energy. These strategies also include arginine deiminase pathway and malolactic fermentation but little is known about their possible interactions of with GABA production. In the present study, the effects of glutamate, arginine, and malate (i.e., the substrates of these acid-resistance pathways) on L. lactis NCDO 2118 growth and GABA production performances were analyzed. Both malate and arginine supplementation resulted in an efficient reduction of acidity and improvement of bacterial biomass compared to glutamate supplementation. Glutamate decarboxylation was limited to narrow environmental conditions (pH < 5.1) and physiological state (stationary phase). However, some conditions were able to improve GABA production or activate glutamate decarboxylation system even outside of this compass. Arginine clearly stimulated glutamate decarboxylation: the highest GABA production (8.6 mM) was observed in cultures supplemented with both arginine and glutamate. The simultaneous addition of arginine, malate, and glutamate enabled earlier GABA production (i.e., during exponential growth) at relatively high pH (6.5). As far as we know, no previous study has reported GABA production in such conditions. Although further studies are needed to understand the molecular basis of these phenomena, these results represent important keys suitable of application in GABA production processes. PMID:27458444

  10. Food Safety: Secretome of Lactococcus lactis and Listeria monocytogenes in competition.

    Directory of Open Access Journals (Sweden)

    Isabella Alloggio

    2015-07-01

    Full Text Available Listeria monocytogenes (LM is a foodborne pathogen responsible of listeriosis. In the spreading of this pathology, milk and dairy products are key reservoir for this pathogen1. Food processing represents one of the major steps that could be linked to LM growth. Inhibition of LM growth through competition of Lactococcus lactis (LAC could represent a solution to this problem. Exoproteome of LM and two different strains of Lactic Acid Bacteria in co-culture have been studied in order to highlight mechanisms of bacterial competition useful to improve food safety. Two different strains of LAC and one strain of LM were cultivated in appropriate medium cultures (BHI, also in competition. Filtrated cultures (SECRETOME were lyophilized and resuspended for proteomics analysis. Shotgun analysis on each secretome was performed on nano UPLC-MS system. Obtained data reveal, during competition, the higher production by LM of moonlighting protein Enolase and Glucose 6 Phosphate isomerase, of Septation ring formation regulator EzrA, involved into cell replication and the lower secretion of Endopeptidase P60. In parallel, L. lactis produced higher amounts of Secreted 45 kDa protein and switched from lantibiotic Nisin A production to Nisin Z production. In competition with LM, LAC strain investigated produce higher amounts of Secreted 45 kDa protein with peptidoglycan lytic activity and the selective secretion of Nisin Z probably to improve lantibiotic solubility in less acidic environment. Next step will be validation of obtained results in dairy products. These results are of interesting to design new strategies of fighting LM as contaminant in food from animal origin.Work supported by Ministry of Health-CCM “Milano EXPO 2015 Project: Garantire la sicurezza alimentare- Valorizzare le produzioni”

  11. Optimization of the Lactococcus lactis nisin-controlled gene expression system NICE for industrial applications

    Directory of Open Access Journals (Sweden)

    Mond James

    2005-05-01

    Full Text Available Abstract Background The nisin-controlled gene expression system NICE of Lactococcus lactis is one of the most widely used expression systems in Gram-positive bacteria. Despite its widespread use, no optimization of the culture conditions and nisin induction has been carried out to obtain maximum yields. As a model system induced production of lysostaphin, an antibacterial protein (mainly against Staphylococcus aureus produced by S. simulans biovar. Staphylolyticus, was used. Three main areas need optimization for maximum yields: cell density, nisin-controlled induction and protein production, and parameters specific for the target-protein. Results In a series of pH-controlled fermentations the following parameters were optimized: pH of the culture, use of NaOH or NH4OH as neutralizing agent, the addition of zinc and phosphate, the fermentation temperature, the time point of induction (cell density of the culture, the amount of nisin added for induction and the amount of three basic medium components, i.e. yeast extract, peptone and lactose. For each culture growth and lysostaphin production was followed. Lysostaphin production yields depended on all parameters that were varied. In the course of the optimization a three-fold increase in lysostaphin yield was achieved from 100 mg/l to 300 mg/l. Conclusion Protein production with the NICE gene expression system in L. lactis strongly depends on the medium composition, the fermentation parameters and the amount of nisin added for induction. Careful optimization of key parameters lead to a significant increase in the yield of the target protein.

  12. AguR, a Transmembrane Transcription Activator of the Putrescine Biosynthesis Operon in Lactococcus lactis, Acts in Response to the Agmatine Concentration.

    Science.gov (United States)

    Linares, Daniel M; Del Rio, Beatriz; Redruello, Begoña; Ladero, Victor; Martin, M Cruz; de Jong, Anne; Kuipers, Oscar P; Fernandez, Maria; Alvarez, Miguel A

    2015-09-01

    Dairy industry fermentative processes mostly use Lactococcus lactis as a starter. However, some dairy L. lactis strains produce putrescine, a biogenic amine that raises food safety and spoilage concerns, via the agmatine deiminase (AGDI) pathway. The enzymatic activities responsible for putrescine biosynthesis in this bacterium are encoded by the AGDI gene cluster. The role of the catabolic genes aguB, aguD, aguA, and aguC has been studied, but knowledge regarding the role of aguR (the first gene in the cluster) remains limited. In the present work, aguR was found to be a very low level constitutively expressed gene that is essential for putrescine biosynthesis and is transcribed independently of the polycistronic mRNA encoding the catabolic genes (aguBDAC). In response to agmatine, AguR acts as a transcriptional activator of the aguB promoter (PaguB), which drives the transcription of the aguBDAC operon. Inverted sequences required for PaguB activity were identified by deletion analysis. Further work indicated that AguR is a transmembrane protein which might function as a one-component signal transduction system that senses the agmatine concentration of the medium and, accordingly, regulates the transcription of the aguBDAC operon through a C-terminal cytoplasmic DNA-binding domain typically found in LuxR-like proteins. PMID:26116671

  13. Induced Levels of Heat Shock Proteins in dnaK mutants of Lactococcus lactis

    DEFF Research Database (Denmark)

    Koch, Birgit; Hammer, Karin; Vogensen, Finn K.;

    1998-01-01

    The bacterial heat shock response is characterized by the elevated expression of a number of chaperone complexes and proteases including the DnaK-GrpE-DnaJ and the GroELS chaperone complexes. In order to investigate the importance of the DnaK chaperone complex for the growth and the heat shock...... the inferred substrate binding site of the DnaK protein, exhibits a pronounced temperature sensitive phenotype and shows altered regulation of the heat shock response. The expression of the heat shock proteins are increased at the normal growth temperature measured both as protein synthesis rates and...... mRNA levels which indicate that DnaK could be involved in the regulation of the heat shock response in Lactococcus lactis. In Bacillus subtilis it has been found by Mogk,A., G.Homouth, C. Scholz, L. Kim, F.X. Schmid, and W. Schumann. 1997. EMBO J. 16: 4579-4590, that the activity of the heat shock...

  14. Mechanism of flavin reduction in the class 1A dihydroorotate dehydrogenase from Lactococcus lactis

    DEFF Research Database (Denmark)

    Fagan, Rebecca L; Jensen, Kaj Frank; Björnberg, Olof; Palfey, Bruce A

    2007-01-01

    is concerted or stepwise was addressed for the class 1A enzyme from Lactococcus lactis by determining kinetic isotope effects (KIEs) on flavin reduction in anaerobic stopped-flow experiments. Isotope effects were determined at two pH values. At pH 7.0, KIEs were approximately 2-fold for DHO labeled....... These isotope effects are consistent with a concerted oxidation of DHO. The pH dependence of reduction was also determined, and a pKa of 8.3 was found. This pKa can be attributed to the ionization of the active site cysteine which deprotonates C5 of DHO during the reaction. To further investigate the...... importance of the active site base, two site-directed mutants were also studied: Cys130Ala (removal of the active site base) and Cys130Ser (replacement with the active site base used by class 2 DHODs). Both mutant enzymes exhibited binding affinities for DHO similar to that of the wild-type enzyme. Reduction...

  15. A genome-scale integration and analysis of Lactococcus lactis translation data.

    Directory of Open Access Journals (Sweden)

    Julien Racle

    Full Text Available Protein synthesis is a template polymerization process composed by three main steps: initiation, elongation, and termination. During translation, ribosomes are engaged into polysomes whose size is used for the quantitative characterization of translatome. However, simultaneous transcription and translation in the bacterial cytosol complicates the analysis of translatome data. We established a procedure for robust estimation of the ribosomal density in hundreds of genes from Lactococcus lactis polysome size measurements. We used a mechanistic model of translation to integrate the information about the ribosomal density and for the first time we estimated the protein synthesis rate for each gene and identified the rate limiting steps. Contrary to conventional considerations, we find significant number of genes to be elongation limited. This number increases during stress conditions compared to optimal growth and proteins synthesized at maximum rate are predominantly elongation limited. Consistent with bacterial physiology, we found proteins with similar rate and control characteristics belonging to the same functional categories. Under stress conditions, we found that synthesis rate of regulatory proteins is becoming comparable to proteins favored under optimal growth. These findings suggest that the coupling of metabolic states and protein synthesis is more important than previously thought.

  16. Improvement of bovine ß-lactoglobulin production and secretion by Lactococcus lactis

    Directory of Open Access Journals (Sweden)

    S. Nouaille

    2005-03-01

    Full Text Available The stabilizing effects of staphylococcal nuclease (Nuc and of a synthetic propeptide (LEISSTCDA, hereafter called LEISS on the production of a model food allergen, bovine ß-lactoglobulin (BLG, in Lactococcus lactis were investigated. The fusion of Nuc to BLG (Nuc-BLG results in higher production and secretion of the hybrid protein. When LEISS was fused to BLG, the production of the resulting protein LEISS-BLG was only slightly improved compared to the one obtained with Nuc-BLG. However, the secretion of LEISS-BLG was dramatically enhanced (~10- and 4-fold higher than BLG and Nuc-BLG, respectively. Finally, the fusion of LEISS to Nuc-BLG resulting in the protein LEISS-Nuc-BLG led to the highest production of the hybrid protein, estimated at ~8 µg/ml (~2-fold higher than Nuc-BLG. In conclusion, the fusions described here led to the improvement of the production and secretion of BLG. These tools will be used to modulate the immune response against BLG via delivery of recombinant lactococci at the mucosal level, in a mouse model of cow's milk allergy.

  17. Prevention of gastrointestinal lead poisoning using recombinant Lactococcus lactis expressing human metallothionein-I fusion protein.

    Science.gov (United States)

    Xiao, Xue; Zhang, Changbin; Liu, Dajun; Bai, Weibin; Zhang, Qihao; Xiang, Qi; Huang, Yadong; Su, Zhijian

    2016-01-01

    Low-level lead poisoning is an insidious disease that affects millions of children worldwide, leading to biochemical and neurological dysfunctions. Blocking lead uptake via the gastrointestinal tract is an important prevention strategy. With this in mind, we constructed the recombinant Lactococcus lactis strain pGSMT/MG1363, which constitutively expressed the fusion protein glutathione S-transferase (GST)-small molecule ubiquitin-like modifier protein (SUMO)-metallothionein-I (GST-SUMO-MT). The thermodynamic data indicated that the average number of lead bound to a GST-SUMO-MT molecule was 3.655 and this binding reaction was a spontaneous, exothermic and entropy-increasing process. The total lead-binding capacity of pGSMT/MG1363 was 4.11 ± 0.15 mg/g dry mass. Oral administration of pGSMT/MG1363 (1 × 10(10) Colony-Forming Units) to pubertal male rats that were also treated with 5 mg/kg of lead acetate daily significantly inhibited the increase of blood lead levels, the impairment of hepatic function and the decrease of testosterone concentration in the serum, which were all impaired in rats treated by lead acetate alone. Moreover, the administration of pGSMT/MG1363 for 6 weeks did not affect the serum concentration of calcium, magnesium, potassium or sodium ions. This study provides a convenient and economical biomaterial for preventing lead poisoning via the digestive tract. PMID:27045906

  18. Comparative effect of Pediococcus acidilactici and Lactococcus lactis on growth performance, survival and enzyme activity of western white leg shrimp (Litopenaeus vannamei)

    OpenAIRE

    Ahmadi, Sara

    2014-01-01

    This study was done in Shahid Kiani Marine Aquaculture Development Center, Choebde, Abadan in order to evaluate the effects of Pediiococcus acidilactici, Lactococcus lactis and vitamin C on growth performance, survival, enzymatic activities and immune responses of L. vannamei during three months. Treatments were included control group, Pediiococcus and Lactococcus treatments which fed with diet containing 1×10P9P cfu gP_1P bacteria and vitamin C. At the end of the experiment, the growth facto...

  19. Proteome analysis of a Lactococcus lactis strain overexpressing gapA suggests that the gene product is an auxiliary glyceraldehyde 3-phosphate dehydrogenase

    DEFF Research Database (Denmark)

    Willemoës, Martin; Kilstrup, Mogens; Roepstorff, Peter;

    2002-01-01

    The sequence of the genome from the Lactococcus lactis subspecies lactis strain IL1403 shows the presence of two reading frames, gapA and gapB, putatively encoding glyceraldehyde 3-phosphate dehydrogenase (GAPDH). Previous proteomic analysis of the L. lactis subspecies cremoris strain MG1363 has ...

  20. Diacetyl and α-Acetolactate Overproduction by Lactococcus lactis subsp. lactis Biovar Diacetylactis Mutants That Are Deficient in α-Acetolactate Decarboxylase and Have a Low Lactate Dehydrogenase Activity

    OpenAIRE

    Monnet, Christophe; Aymes, Frédéric; Corrieu, Georges

    2000-01-01

    Lactococcus lactis subsp. lactis biovar diacetylactis strains are utilized in several industrial processes for producing the flavoring compound diacetyl or its precursor α-acetolactate. Using random mutagenesis with nitrosoguanidine, we selected mutants that were deficient in α-acetolactate decarboxylase and had low lactate dehydrogenase activity. The mutants produced large amounts of α-acetolactate in anaerobic milk cultures but not in aerobic cultures, except when the medium was supplemente...

  1. The carB gene encoding the large subunit of carbamoylphosphate synthetase from Lactococcus lactis is transcribed monocistronically

    DEFF Research Database (Denmark)

    Martinussen, Jan; Hammer, Karin

    1998-01-01

    The biosynthesis of carbamoylphosphate is catalysed by the heterodimeric enzyme carbamoylphosphate synthetase (CPSase). The genes encoding the two subunits in procaryotes are normally transcribed as an operon, whereas in Lactococcus lactis, the gene encoding the large subunit (carB) is shown to be...... an isolated transcriptional unit. Carbamoylphosphate is a precursor in the biosynthesis of both pyrimidine nucleotides and arginine. By mutant analysis L. lactis is shown to possess only one carB gene; the same gene product is thus required for both biosynthetic pathways. Furthermore, arginine may...... satisfy the requirement for carbamoylphosphate in pyrimidine biosynthesis through degradation by the arginine deiminase pathway. The expression of the carB gene is subject to regulation at the level of transcription by pyrimidines most probably by an attenuator mechanism. Upstream of the carB gene, an...

  2. In Situ Determination of the Intracellular pH of Lactococcus lactis and Lactobacillus plantarum during Pressure Treatment

    OpenAIRE

    Molina-Gutierrez, Adriana; Stippl, Volker; Delgado, Antonio; Gänzle, Michael G.; Rudi F. Vogel

    2002-01-01

    Hydrostatic pressure may affect the intracellular pH of microorganisms by (i) enhancing the dissociation of weak organic acids and (ii) increasing the permeability of the cytoplasmic membrane and inactivation of enzymes required for pH homeostasis. The internal pHs of Lactococcus lactis and Lactobacillus plantarum during and after pressure treatment at 200 and 300 MPa and at pH values ranging from 4.0 to 6.5 were determined. Pressure treatment at 200 MPa for up to 20 min did not reduce the vi...

  3. Purification and characterization of a cell wall peptidase from Lactococcus lactis subsp. cremoris IMN-C12.

    OpenAIRE

    Sahlstrøm, S; J. Chrzanowska; Sørhaug, T

    1993-01-01

    A peptidase from the cell wall fraction of Lactococcus lactis subsp. cremoris IMN-C12 has been purified to homogeneity by hydrophobic interaction chromatography, two steps of anion-exchange chromatography, and gel filtration. The molecular mass of the purified enzyme was estimated to be 72 kDa by gel filtration and 23 kDa by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The enzyme has a pI of 4.0, and it has the following N-terminal sequence from the 2nd to the 17th amino acid re...

  4. Estudio de la expresión de enzimas del metabolismo de aminoácidos en lactococcus lactis

    OpenAIRE

    García-Cayuela, Tomás

    2011-01-01

    Los aminoácidos son fundamentales para la supervivencia y el desarrollo de bacterias. Son las principales fuentes de nitrógeno y están implicados en la producción de energía, el control del pH intracelular y la regeneración de cofactores. Además, son los precursores de una larga variedad de compuestos volátiles en Lactococcus lactis y, por ello, diversas enzimas son consideradas clave para su formación, como aminotransferasas, deshidrogenasas, liasas y decarboxilasas, entre otras. Estas enzim...

  5. Characterization and overexpression of the Lactococcus lactis pepN gene and localization of its product, aminopeptidase N.

    OpenAIRE

    van Alen-Boerrigter, I J; Baankreis, R; de Vos, W M

    1991-01-01

    The chromosomal pepN gene encoding lysyl-aminopeptidase activity in Lactococcus lactis has been identified in a lambda EMBL3 library in Escherichia coli by using an immunological screening with antiserum against a purified aminopeptidase fraction. The pepN gene was localized and subcloned in E. coli on the basis of its expression and hybridization to a mixed-oligonucleotide probe for the previously determine N-terminal amino acid sequence of lysyl-aminopeptidase (P. S. T. Tan and W. N. Koning...

  6. The extracellular PI-type proteinase of Lactococcus lactis hydrolyzes beta-casein into more than one hundred different oligopeptides.

    OpenAIRE

    Juillard, V; van der Laan, H.; Kunji, E R; Jeronimus-Stratingh, C M; Bruins, A P; Konings, W. N.

    1995-01-01

    The peptides released from beta-casein by the action of PI-type proteinase (PrtP) from Lactococcus lactis subsp. cremoris Wg2 have been identified by on-line coupling of liquid chromatography to mass spectrometry. After 24 h of incubation of beta-casein with purified PrtP, a stable mixture of peptides was obtained. The trifluoroacetic acid-soluble peptides of this beta-casein hydrolysate were fractionated by high-performance liquid chromatography and introduced into the liquid chromatography-...

  7. Genetically engineered Lactococcus lactis protect against house dust mite allergy in a BALB/c mouse model.

    Directory of Open Access Journals (Sweden)

    Chunqing Ai

    Full Text Available Mucosal vaccine based on lactic acid bacteria is an attractive concept for the prevention and treatment of allergic diseases, but their mechanisms of action in vivo are poorly understood. Therefore, we sought to investigate how recombinant major dust mite allergen Der p2-expressing Lactococcus lactis as a mucosal vaccine induced the immune tolerance against house dust mite allergy in a mouse model.Three strains of recombinant L. lactis producing Der p2 in different cell components (extracellular, intracellular and cell wall were firstly constructed. Their prophylactic potential was evaluated in a Der p2-sensitised mouse model, and immunomodulation properties at the cellular level were determined by measuring cytokine production in vitro.Der p2 expressed in the different recombinant L. lactis strains was recognized by a polyclonal anti-Der p2 antibody. Oral treatment with the recombinant L. lactis prior sensitization significantly prevented the development of airway inflammation in the Der p2-sensitized mice, as determined by the attenuation of inflammatory cells infiltration in the lung tissues and decrease of Th2 cytokines IL-4 and IL-5 levels in bronchoalveolar lavage. In addition, the serum allergen-specific IgE levels were significantly reduced, and the levels of IL-4 in the spleen and mesenteric lymph nodes cell cultures were also markedly decreased upon allergen stimulation in the mice fed with the recombinant L. lactis strains. These protective effects correlated with a significant up-regulation of regulatory T cells in the mesenteric lymph nodes.Oral pretreatment with live recombinant L. lactis prevented the development of allergen-induced airway inflammation primarily by the induction of specific mucosal immune tolerance.

  8. Nisin production of Lactococcus lactis N8 with hemin-stimulated cell respiration in fed-batch fermentation system.

    Science.gov (United States)

    Kördikanlıoğlu, Burcu; Şimşek, Ömer; Saris, Per E J

    2015-01-01

    In this study, nisin production of Lactococcus lactis N8 was optimized by independent variables of glucose, hemin and oxygen concentrations in fed-batch fermentation in which respiration of cells was stimulated with hemin. Response surface model was able to explain the changes of the nisin production of L. lactis N8 in fed-batch fermentation system with high fidelity (R(2) 98%) and insignificant lack of fit. Accordingly, the equation developed indicated the optimum parameters for glucose, hemin, and dissolved oxygen were 8 g L(-1) h(-1) , 3 μg mL(-1) and 40%, respectively. While 1711 IU mL(-1) nisin was produced by L. lactis N8 in control fed-batch fermentation, 5410 IU mL(-1) nisin production was achieved within the relevant optimum parameters where the respiration of cell was stimulated with hemin. Accordingly, nisin production was enhanced 3.1 fold in fed-batch fermentation using hemin. In conclusion the nisin production of L. lactis N8 was enhanced extensively as a result of increasing the biomass by stimulating the cell respiration with adding the hemin in the fed-batch fermentation. PMID:25826783

  9. Interaction of Saccharomyces cerevisiae and Lactococcus lactis in the fermentation and quality of artisanal cachaça

    Directory of Open Access Journals (Sweden)

    Fernanda Paula Carvalho

    2014-11-01

    Full Text Available Lactococcus lactis and Saccharomyces cerevisiae in co-culture were evaluated during sugar cane fermentantion for cachaça production. The inocula containing L. lactis UFLA CA 312 and S. cerevisiae UFLA CA 11 were used in the population of approximately 105 CFU mL-1 and 108 CFU mL-1,  respectively. The sugar cane medium plus 1% of yeast extract (SCM was efficient for growth of L. lactis UFLA CA 312 and S. cerevisiae UFLA CA 11 (letter b -Tukey test. In flasks and vats fermentation the growth of UFLA CA 11 was not negatively influenced by L. lactis UFLA CA 312. However, after 19 h of fermentation, bacterial population showed a slight decrease. Considering parameters higher alcohols and aldehydes, cachaça produced by pure culture of S. cerevisiae was similar to cachaça produced by mixed culture. Cachaça produced by mixed culture showed high values of volatile acidity (letter b -Scott-Knott test being characterized by this parameters in the principal component analysis. High percentage of acceptance (81.10% for the attribute aroma was observed in samples from cachaça produced by mixed culture.

  10. Identification and characterization of tetracycline resistance in Lactococcus lactis isolated from Polish raw milk and fermented artisanal products.

    Science.gov (United States)

    Zycka-Krzesinska, Joanna; Boguslawska, Joanna; Aleksandrzak-Piekarczyk, Tamara; Jopek, Jakub; Bardowski, Jacek K

    2015-10-15

    To assess the occurrence of antibiotic-resistant Lactic Acid Bacteria (LAB) in Polish raw milk and fermented artisanal products, a collection comprising 500 isolates from these products was screened. Among these isolates, six strains (IBB28, IBB160, IBB161, IBB224, IBB477 and IBB487) resistant to tetracycline were identified. The strains showing atypical tetracycline resistance were classified as Lactococcus lactis: three of them were identified as L. lactis subsp. cremoris (IBB224, IBB477 and IBB487) and the other three (IBB28, IBB160, IBB161) were identified as L. lactis subsp. lactis. The mechanism involving Ribosomal Protection Proteins (RPP) was identified as responsible for tetracycline resistance. Three of the tested strains (IBB28, IBB160 and IBB224) had genes encoding the TetS protein, whereas the remaining three (IBB161, IBB477 and IBB487) expressed TetM. The results also demonstrated that the genes encoding these proteins were located on genetic mobile elements. The tet(S) gene was found to be located on plasmids, whereas tet(M) was found within the Tn916 transposon. PMID:26204235

  11. Hsp65-producing Lactococcus lactis prevents experimental autoimmune encephalomyelitis in mice by inducing CD4+LAP+ regulatory T cells.

    Science.gov (United States)

    Rezende, Rafael M; Oliveira, Rafael P; Medeiros, Samara R; Gomes-Santos, Ana C; Alves, Andrea C; Loli, Flávia G; Guimarães, Mauro A F; Amaral, Sylvia S; da Cunha, André P; Weiner, Howard L; Azevedo, Vasco; Miyoshi, Anderson; Faria, Ana M C

    2013-02-01

    Heat shock proteins (Hsps) participate in the cellular response to stress and they are hiperexpressed in inflammatory conditions. They are also known to play a major role in immune modulation, controlling, for instance, autoimmune responses. In this study, we showed that oral administration of a recombinant Lactococcus lactis strain that produces and releases LPS-free Hsp65 prevented the development of experimental autoimmune encephalomyelitis (EAE) in C57BL/6 mice. This was confirmed by the reduced inflammatory cell infiltrate and absence of injury signs in the spinal cord. The effect was associated with reduced IL-17 and increased IL-10 production in mesenteric lymph node and spleen cell cultures. Hsp65-producing-L. lactis-fed mice had a remarkable increase in the number of natural and inducible CD4+Foxp3+ regulatory T (Treg) cells and CD4+LAP+ (Latency-associated peptide) Tregs - which express the membrane-bound TGF-β - in spleen, inguinal and mesenteric lymph nodes as well as in spinal cord. Moreover, many Tregs co-expressed Foxp3 and LAP. In vivo depletion of LAP+ cells abrogated the effect of Hsp65-producing L. lactis in EAE prevention and worsened disease in medium-fed mice. Thus, Hsp65-L.lactis seems to boost this critical regulatory circuit involved in controlling EAE development in mice. PMID:22939403

  12. Oral Vaccination with the Porcine Rotavirus VP4 Outer Capsid Protein Expressed by Lactococcus lactis Induces Specific Antibody Production

    Directory of Open Access Journals (Sweden)

    Yi-jing Li

    2010-01-01

    Full Text Available The objective of this study to design a delivery system resistant to the gastrointestinal environment for oral vaccine against porcine rotavirus. Lactococcus lactis NZ9000 was transformed with segments of vP4 of the porcine rotavirus inserted into the pNZ8112 surface-expression vector, and a recombinant L. lactis expressing VP4 protein was constructed. An approximately 27 kDa VP4 protein was confirmed by SDS-PAGE , Western blot and immunostaining analysis. BALB/c mice were immunized orally with VP4-expression recombinant L. lactis and cellular, mucosal and systemic humoral immune responses were examined. Specific anti-VP4 secretory IgA and IgG were found in feces, ophthalmic and vaginal washes and in serum. The induced antibodies demonstrated neutralizing effects on porcine rotavirus infection on MA104 cells. Our findings suggest that oral immunization with VP4-expressing L. lactis induced both specific local and systemic humoral and cellular immune responses in mice.

  13. Bacteriocinogenic Lactococcus lactis subsp. lactis DF04Mi isolated from goat milk: Application in the control of Listeria monocytogenes in fresh Minas-type goat cheese.

    Science.gov (United States)

    Furtado, Danielle N; Todorov, Svetoslav D; Landgraf, Mariza; Destro, Maria T; Franco, Bernadette D G M

    2015-03-01

    Listeria monocytogenes is a pathogen frequently found in dairy products. Its control in fresh cheeses is difficult, due to the psychrotrophic properties and salt tolerance. Bacteriocinogenic lactic acid bacteria (LAB) with proven in vitro antilisterial activity can be an innovative technological approach but their application needs to be evaluated by means of in situ tests. In this study, a novel bacteriocinogenic Lactococcus lactis strain ( Lc . lactis DF4Mi), isolated from raw goat milk, was tested for control of growth of L. monocytogenes in artificially contaminated fresh Minas type goat cheese during storage under refrigeration. A bacteriostatic effect was achieved, and counts after 10 days were 3 log lower than in control cheeses with no added LAB. However, this effect did not differ significantly from that obtained with a non-bacteriocinogenic Lc. lactis strain. Addition of nisin (12.5 mg/kg) caused a rapid decrease in the number of viable L. monocytogenes in the cheeses, suggesting that further studies with the purified bacteriocin DF4Mi may open new possibilities for this strain as biopreservative in dairy products. PMID:26221109

  14. Bacteriocinogenic Lactococcus lactis subsp. lactis DF04Mi isolated from goat milk: Application in the control of Listeria monocytogenes in fresh Minas-type goat cheese

    Directory of Open Access Journals (Sweden)

    Danielle N. Furtado

    2015-03-01

    Full Text Available Listeria monocytogenes is a pathogen frequently found in dairy products. Its control in fresh cheeses is difficult, due to the psychrotrophic properties and salt tolerance. Bacteriocinogenic lactic acid bacteria (LAB with proven in vitro antilisterial activity can be an innovative technological approach but their application needs to be evaluated by means of in situ tests. In this study, a novel bacteriocinogenic Lactococcus lactis strain (Lc. lactis DF4Mi, isolated from raw goat milk, was tested for control of growth of L. monocytogenes in artificially contaminated fresh Minas type goat cheese during storage under refrigeration. A bacteriostatic effect was achieved, and counts after 10 days were 3 log lower than in control cheeses with no added LAB. However, this effect did not differ significantly from that obtained with a non-bacteriocinogenic Lc. lactis strain. Addition of nisin (12.5 mg/kg caused a rapid decrease in the number of viable L. monocytogenes in the cheeses, suggesting that further studies with the purified bacteriocin DF4Mi may open new possibilities for this strain as biopreservative in dairy products.

  15. Some chemical and physical properties of nisin, a small-protein antibiotic produced by Lactococcus lactis.

    Science.gov (United States)

    Liu, W; Hansen, J N

    1990-08-01

    Nisin is a small gene-encoded antimicrobial protein produced by Lactococcus lactis that contains unusual dehydroalanine and dehydrobutyrine residues. The reactivity of these residues toward nucleophiles was explored by reacting nisin with a variety of mercaptans. The kinetics of reaction with 2-mercaptoethane-sulfonate and thioglycolate indicated that the reaction pathway includes a binding step. Reaction of nisin at high pH resulted in the formation of multimeric products, apparently as a result of intramolecular and intermolecular reactions between nucleophilic groups and the dehydro residues. One of the nucleophiles had a pKa of about 9.8. The unique vinyl protons of the dehydro residues that give readily identifiable proton nuclear magnetic resonances were used to observe the addition of nucleophiles to the dehydro moiety. After reaction with nucleophiles, nisin lost its antibiotic activity and no longer showed the dehydro resonances, indicating that the dehydro groups had been modified. The effect of pH on the solubility of nisin was determined; the solubility was quite high at low pH (57 mg/ml at pH 2) and was much lower at high pH (0.25 mg/ml at pH 8 to 12), as measured before significant pH-induced chemical modification had occurred. High-performance liquid chromatography on a C18 column was an effective technique for separating unmodified nisin from its reaction products. The cyanogen bromide cleavage products of nisin were about 90% less active toward inhibition of bacterial spore outgrowth than was native nisin. These results are consistent with earlier observations, which suggested that the dehydro residues of nisin have a role in the mechanism of antibiotic action, in which they act as electrophilic Michael acceptors toward nucleophiles in the cellular target. PMID:2119570

  16. A derivative of Lactococcus lactis strain H61 with less interleukin-12 induction has a different cell wall.

    Science.gov (United States)

    Kimoto-Nira, H; Suzuki, C; Aoki, R; Kobayashi, M; Mizumachi, K

    2012-06-01

    Lactococcus lactis H61 can increase the cellular immune responses of aged (14-mo-old) senescence-accelerated mice. The aim of this study was to investigate the factors contributing to IL-12 induction by strain H61 by analyzing strains derived from it. Strain H61 derivative no. 13 was obtained by growing the parent strain at 37°C. This derivative induced significantly lower production of IL-12 from J774.1 macrophage cells than did the parent strain H61. The 2 strains differed in the resistance of their whole cells or cell walls to lysozyme, a cell wall-degrading enzyme. Sodium hydroxide treatment to de-O-acetylate muramic acid in the cell walls of the 2 strains reduced the lysozyme resistance, compared with untreated cell walls: at 3h after adding lysozyme, the lysozyme resistance of untreated and NaOH treated cell wall from strain H61 was 55.4% and 11.7%, respectively. The values of untreated and NaOH-treated cell walls from strain no.13 were 73.7 and 42.8%, respectively. The reduction was higher in strain H61, indicating that the cell walls of strain H61 were highly O-acetylated. Trichloroacetic acid treatment to remove wall-associated polymers such as teichoic acids made the lysozyme resistance of the cell walls of both strains similar. The sugar content of cell walls prepared from strain H61 was significantly higher than that of strain no. 13 cell wall. A derivative with less activity for inducing IL-12 by macrophage cells had less O-acetylation and had lower sugar content in the cell wall than did strain H61. Modifying the cell wall of strain H61 may be a useful way to regulate its ability to induce IL-12. Strain H61 has been used as a starter bacterium in the dairy industry. This study could lead to enhancing the value of dairy products made by strain H61 by characterizing the key factor(s) responsible for its stimulation of immunity. PMID:22612923

  17. Induction of antigen-specific tolerance by oral administration of Lactococcus lactis delivered immunodominant DQ8-restricted gliadin peptide in sensitized nonobese diabetic Abo Dq8 transgenic mice

    NARCIS (Netherlands)

    I.L. Huibregtse; E.V. Marietta; S. Rashtak; F. Koning; P. Rottiers; C.S. David; S.J.H. van Deventer; J.A. Murray

    2009-01-01

    Active delivery of recombinant autoantigens or allergens at the intestinal mucosa by genetically modified Lactococcus lactis (LL) provides a novel therapeutic approach for the induction of tolerance. Celiac disease is associated with either HLA-DQ2- or HLA-DQ8-restricted responses to specific antige

  18. How to distinguish between the vacuum cleaner and flippase mechanisms of the LmrA multi-drug transporter in Lactococcus lactis

    NARCIS (Netherlands)

    Hofmeyr, JHS; Rohwer, JM; Snoep, JL; Westerhoff, HV; Konings, WN

    2002-01-01

    A numerical model of the LmrA multi-drug transport system of Lactococcus lactis is used to explore the possibility of distinguishing experimentally between two putative transport mechanisms, i.e., the vacuum-cleaner and the flippase mechanisms. This comparative model also serves as an example of num

  19. Complete sequences of four plasmids of Lactococcus lactis subsp. cremoris SK11 reveal extensive adaptation to the dairy environment.

    Science.gov (United States)

    Siezen, Roland J; Renckens, Bernadet; van Swam, Iris; Peters, Sander; van Kranenburg, Richard; Kleerebezem, Michiel; de Vos, Willem M

    2005-12-01

    Lactococcus lactis strains are known to carry plasmids encoding industrially important traits. L. lactis subsp. cremoris SK11 is widely used by the dairy industry in cheese making. Its complete plasmid complement was sequenced and found to contain the plasmids pSK11A (10,372 bp), pSK11B (13,332 bp), pSK11L (47,165 bp), and pSK11P (75,814 bp). Six highly homologous repB-containing replicons were found, all belonging to the family of lactococcal theta-type replicons. Twenty-three complete insertion sequence elements segment the plasmids into numerous modules, many of which can be identified as functional units or containing functionally related genes. Plasmid-encoded functions previously known to reside on L. lactis SK11 plasmids were now mapped in detail, e.g., lactose utilization (lacR-lacABCDFEGX), the proteolytic system (prtM-prtP, pepO, pepF), and the oligopeptide permease system (oppDFBCA). Newly identified plasmid-encoded functions could facilitate the uptake of various cations, while the pabA and pabB genes could be essential for folate biosynthesis. A competitive advantage could be obtained by using the putative flavin adenine dinucleotide-dependent d-lactate dehydrogenase and oxalate:formate antiporter for enhanced ATP synthesis, while the activity of the predicted alpha-acetolactate decarboxylase may contribute to the formation of an additional electron sink. Various stress response proteins are plasmid encoded, which could enhance strain robustness. A substantial number of these "adaptation" genes have not been described before on L. lactis plasmids. Moreover, several genes were identified for the first time in L. lactis, possibly reflecting horizontal gene transfer. PMID:16332824

  20. Complete Genome Sequence of Lactococcus lactis subsp. lactis CV56, a Probiotic Strain Isolated from the Vaginas of Healthy Women▿

    OpenAIRE

    Gao, Yong; Lu, Ying; Teng, Kun-Ling; Chen, Mei-Ling; Zheng, Hua-Jun; Zhu, Yong-Qiang; Zhong, Jin

    2011-01-01

    Lactic acid bacteria that exist in the urinogenital system play an important role in maintaining the health of the host. Here, we report the finished and annotated genome of a Lactococcus strain that was isolated from the vaginas of healthy women and shows probiotic properties, including nisin A production and adhesion to vaginal epithelial cells.

  1. Production of Ginsenoside F2 by Using Lactococcus lactis with Enhanced Expression of β-Glucosidase Gene from Paenibacillus mucilaginosus.

    Science.gov (United States)

    Li, Ling; Shin, So-Yeon; Lee, Soo Jin; Moon, Jin Seok; Im, Wan Taek; Han, Nam Soo

    2016-03-30

    This study aimed to produce a pharmacologically active minor ginsenoside F2 from the major ginsenosides Rb1 and Rd by using a recombinant Lactococcus lactis strain expressing a heterologous β-glucosidase gene. The nucleotide sequence of the gene (BglPm) was derived from Paenibacillus mucilaginosus and synthesized after codon optimization, and the two genes (unoptimized and optimized) were expressed in L. lactis NZ9000. Codon optimization resulted in reduction of unfavorable codons by 50% and a considerable increase in the expression levels (total activities) of β-glucosidases (0.002 unit/mL, unoptimized; 0.022 unit/mL, optimized). The molecular weight of the enzyme was 52 kDa, and the purified forms of the enzymes could successfully convert Rb1 and Rd into F2. The permeabilized L. lactis expressing BglPm resulted in a high conversion yield (74%) of F2 from the ginseng extract. Utilization of this microbial cell to produce F2 may provide an alternative method to increase the health benefits of Panax ginseng. PMID:26494255

  2. Preliminary X-ray crystallographic analysis of the d-xylulose 5-phosphate phosphoketolase from Lactococcus lactis

    International Nuclear Information System (INIS)

    The expression, purification, preliminary crystallization and crystallographic analysis of phosphoketolase from L. lactis ssp. lactis (strain IL 1403) are reported. Phosphoketolases are thiamine diphosphate-dependent enzymes which play a central role in the pentose-phosphate pathway of heterofermentative lactic acid bacteria. They belong to the family of aldehyde-lyases and in the presence of phosphate ion cleave the carbon–carbon bond of the specific substrate d-xylulose 5-phosphate (or d-fructose 6-phosphate) to give acetyl phosphate and d-glyceraldehyde 3-phosphate (or d-erythrose 4-phosphate). Structural information about phosphoketolases is particularly important in order to fully understand their mechanism as well as the steric course of phosphoketolase-catalyzed reactions. Here, the purification, preliminary crystallization and crystallographic characterization of d-xylulose 5-phosphate phosphoketolase from Lactococcus lactis are reported. The presence of thiamine diphosphate during purification was essential for the enzymatic activity of the purified protein. The crystals belonged to the monoclinic space group P21. Diffraction data were obtained to a resolution of 2.2 Å

  3. Improvement in lactic acid production from starch using alpha-amylase-secreting Lactococcus lactis cells adapted to maltose or starch.

    Science.gov (United States)

    Okano, Kenji; Kimura, Sakurako; Narita, Junya; Fukuda, Hideki; Kondo, Akihiko

    2007-07-01

    To achieve direct and efficient lactic acid production from starch, a genetically modified Lactococcus lactis IL 1403 secreting alpha-amylase, which was obtained from Streptococcus bovis 148, was constructed. Using this strain, the fermentation of soluble starch was achieved, although its rate was far from efficient (0.09 g l(-1) h(-1) lactate). High-performance liquid chromatography revealed that maltose accumulated during fermentation, and this was thought to lead to inefficient fermentation. To accelerate maltose consumption, starch fermentation was examined using L. lactis cells adapted to maltose instead of glucose. This led to a decrease in the amount of maltose accumulation in the culture, and, as a result, a more rapid fermentation was accomplished (1.31 g l(-1) h(-1) lactate). Maximum volumetric lactate productivity was further increased (1.57 g l(-1) h(-1) lactate) using cells adapted to starch, and a high yield of lactate (0.89 g of lactate per gram of consumed sugar) of high optical purity (99.2% of L: -lactate) was achieved. In this study, we propose a new approach to lactate production by alpha-amylase-secreting L. lactis that allows efficient fermentation from starch using cells adapted to maltose or starch before fermentation. PMID:17384945

  4. Producción de ácido láctico por una mezcla de Lactococcus lactis y Streptococcus salivarius en fermentaciones en discontinuo Lactic acid production from a mixture of cultures of Lactococcus lactis and Streptococcus salivarius using batch fermentation

    Directory of Open Access Journals (Sweden)

    Rodríguez de Stouvenel Aida

    2005-07-01

    Full Text Available Se estudió la producción de ácido láctico (AL, la conversión de sustrato (CG, y el rendimiento(Yp/s de Lactococcus lactis, Streptococcus salivarius y una mezcla 1:1 de ambas cepas en sustrato glucosado. Lactococcus lactis se seleccionó de 20 cepas homofermentativas aisladas de cultivos de caña de azúcar variedad CC85-92 y Streptococcus salivarius se aisló de un fermento láctico comercial. En fermentaciones llevadas a cabo con la mezcla microbiana, a 32 °C con 60 gL-1 de glucosa y pH 6,0 se obtuvo un máximo de 47,63 gL-1 de ácido láctico, conversión de glucosa de 95,4% y rendimiento en producto de 0,83 gg-1. Palabras clave: caña de azúcar, Lactococcus lactis, Streptococcus salivarius, mezcla de cepas.Production of lactic acid (LA, yield (Yp/s and substrate conversion (SC from Lactococcus lactis, Streptococcus salivarius and their mixtures were tested. Lactococcus lactis was selected from 20 homofermentative strains isolated from a sugar cane crop (variety CC85-92 and Streptococcus salivarius was isolated from a commercial lactic ferment. Batch fermentation experiments at 32 C with a glucose concentration of 60 gL-1 and a pH of 6,0 were carried out. A maximum of 47,63 gL-1 of lactic acid concentration, 95,4% of substrate conversion and 83 gg-1 were obtained from the mixture of strains after a fermentation of 48 h. Key words: sugar cane, Lactococcus lactis, Streptococcus salivarius, mixture of strains.

  5. Complete genome sequences of four novel Lactococcus lactis phages distantly related to the Rare 1706 Phage Species

    DEFF Research Database (Denmark)

    Kot, Witold Piotr; Neve, Horst; Vogensen, Finn Kvist;

    2014-01-01

    Lactoccocus lactis is a Gram-positive bacterium widely used in the dairy industry in the production of an array of cheeses and other fermented milk products. Here, we describe the sequencing and genome annotations of a set of four phages virulent to L. lactis and exhibiting similarities to phage...

  6. Engineering the cell surface display of cohesins for assembly of cellulosome-inspired enzyme complexes on Lactococcus lactis

    Directory of Open Access Journals (Sweden)

    Wieczorek Andrew S

    2010-09-01

    Full Text Available Abstract Background The assembly and spatial organization of enzymes in naturally occurring multi-protein complexes is of paramount importance for the efficient degradation of complex polymers and biosynthesis of valuable products. The degradation of cellulose into fermentable sugars by Clostridium thermocellum is achieved by means of a multi-protein "cellulosome" complex. Assembled via dockerin-cohesin interactions, the cellulosome is associated with the cell surface during cellulose hydrolysis, forming ternary cellulose-enzyme-microbe complexes for enhanced activity and synergy. The assembly of recombinant cell surface displayed cellulosome-inspired complexes in surrogate microbes is highly desirable. The model organism Lactococcus lactis is of particular interest as it has been metabolically engineered to produce a variety of commodity chemicals including lactic acid and bioactive compounds, and can efficiently secrete an array of recombinant proteins and enzymes of varying sizes. Results Fragments of the scaffoldin protein CipA were functionally displayed on the cell surface of Lactococcus lactis. Scaffolds were engineered to contain a single cohesin module, two cohesin modules, one cohesin and a cellulose-binding module, or only a cellulose-binding module. Cell toxicity from over-expression of the proteins was circumvented by use of the nisA inducible promoter, and incorporation of the C-terminal anchor motif of the streptococcal M6 protein resulted in the successful surface-display of the scaffolds. The facilitated detection of successfully secreted scaffolds was achieved by fusion with the export-specific reporter staphylococcal nuclease (NucA. Scaffolds retained their ability to associate in vivo with an engineered hybrid reporter enzyme, E. coli β-glucuronidase fused to the type 1 dockerin motif of the cellulosomal enzyme CelS. Surface-anchored complexes exhibited dual enzyme activities (nuclease and β-glucuronidase, and were

  7. Lactococcus lactis expressing either Staphylococcus aureus fibronectin-binding protein A or Listeria monocytogenes internalin A can efficiently internalize and deliver DNA in human epithelial cells.

    Science.gov (United States)

    Innocentin, Silvia; Guimarães, Valeria; Miyoshi, Anderson; Azevedo, Vasco; Langella, Philippe; Chatel, Jean-Marc; Lefèvre, François

    2009-07-01

    Lactococci are noninvasive bacteria frequently used as protein delivery vectors and, more recently, as in vitro and in vivo DNA delivery vehicles. We previously showed that a functional eukaryotic enhanced green fluorescent protein (eGFP) expression plasmid vector was delivered in epithelial cells by Lactococcus lactis producing Listeria monocytogenes internalin A (L. lactis InlA(+)), but this strategy is limited in vivo to transgenic mice and guinea pigs. In this study, we compare the internalization ability of L. lactis InlA(+) and L. lactis producing either the fibronectin-binding protein A of Staphylococcus aureus (L. lactis FnBPA(+)) or its fibronectin binding domains C and D (L. lactis CD(+)). L. lactis FnBPA(+) and L. lactis InlA(+) showed comparable internalization rates in Caco-2 cells, while the internalization rate observed with L. lactis CD(+) was lower. As visualized by conventional and confocal fluorescence microscopy, large clusters of L. lactis FnBPA(+), L. lactis CD(+), and L. lactis InlA(+) were present in the cytoplasm of Caco-2 cells after internalization. Moreover, the internalization rates of Lactobacillus acidophilus NCFM and of an NCFM mutant strain with the gene coding for the fibronectin-binding protein (fbpA) inactivated were also evaluated in Caco-2 cells. Similar low internalization rates were observed for both wild-type L. acidophilus NCFM and the fbpA mutant, suggesting that commensal fibronectin binding proteins have a role in adhesion but not in invasion. L. lactis FnBPA(+), L. lactis CD(+), and L. lactis InlA(+) were then used to deliver a eukaryotic eGFP expression plasmid in Caco-2 cells: flow cytometry analysis showed that the highest percentage of green fluorescent Caco-2 cells was observed after coculture with either L. lactis FnBPA(+) or L. lactis InlA(+). Analysis of the in vivo efficiency of these invasive recombinant strains is currently in progress to validate their potential as DNA vaccine delivery vehicles. PMID

  8. Sugar Utilization and Acid Production by Free and Entrapped Cells of Streptococcus salivarius subsp. thermophilus, Lactobacillus delbrueckii subsp. bulgaricus, and Lactococcus lactis subsp. lactis in a Whey Permeate Medium

    Science.gov (United States)

    Audet, Pascal; Paquin, Celine; Lacroix, Christophe

    1989-01-01

    Cells of Streptococcus salivarius subsp. thermophilus and Lactococcus lactis subsp. lactis entrapped in k-carrageenan-locust bean gum gel performed similarly to free cells in the conversion of lactose to lactic acid. Bead diameter influenced the fermentation rate. Cells entrapped in smaller beads (0.5 to 1.0 mm) showed higher release rates, higher lactose, glucose, and formic acid utilization, higher galactose accumulation, and higher lactic acid production than did cells entrapped in larger beads (1.0 to 2.0 mm). Values for smaller beads were comparable with those for free cells. Immobilization affected the fermentation rate of lactic acid bacteria, especially Lactobacillus delbrueckii subsp. bulgaricus. Entrapped cells of L. delbrueckii subsp. bulgaricus demonstrated a lower lactic acid production than did free cells in batch fermentation. The kinetics of the production of formic and pyruvic acids by L. lactis subsp. lactis and S. salivarius subsp. thermophilus are presented. PMID:16347822

  9. Classification of Lactococcus lactis cell envelope proteinase based on gene sequencing, peptides formed after hydrolysis of milk, and computer modeling

    DEFF Research Database (Denmark)

    Børsting, Mette Winther; Qvist, K.B.; Brockmann, E.; Vindeløv, J.; Pedersen, T.L.; Vogensen, Finn Kvist; Ardö, Ylva Margareta

    2015-01-01

    Lactococcus lactis strains depend on a proteolytic system for growth in milk to release essential AA from casein. The cleavage specificities of the cell envelope proteinase (CEP) can vary between strains and environments and whether the enzyme is released or bound to the cell wall. Thirty-eight Lc....... lactis strains were grouped according to their CEP AA sequences and according to identified peptides after hydrolysis of milk. Finally, AA positions in the substrate binding region were suggested by the use of a new CEP template based on Streptococcus C5a CEP. Aligning the CEP AA sequences of 38 strains...... of Lc. lactis showed that 21 strains, which were previously classified as group d, could be subdivided into 3 groups. Independently, similar subgroupings were found based on comparison of the Lc. lactis CEP AA sequences and based on normalized quantity of identified peptides released from αS1-casein...

  10. Transfer of nisin gene cluster from Lactococcus lactis ATCC 11454 into the chromosome of Bacillus subtilis 168.

    Science.gov (United States)

    Yuksel, Sahru; Hansen, J Norman

    2007-03-01

    Nisin is an antimicrobial peptide produced by certain strains of Lactococcus lactis. It is a gene-encoded peptide that contains unusual amino acid residues. These novel residues are introduced by posttranslational modification machinery and confer unique chemical and physical properties that are not attainable by regular amino acid residues. To study the modification mechanisms and to create structural analogs with superior properties, it would be advantageous to insert the nisin genes into a bacterial strain that is amenable to genetic manipulation. In this study, we report the cloning and integration of the complete and intact nisin gene cluster into the Bacillus subtilis 168 chromosome. Furthermore, we demonstrate that the nisin genes are transcriptionally active. These results should greatly facilitate the studies of the genes and proteins involved in nisin expression, as well as provide a standard system for the manipulation and expression of genes involved in other members of the lantibiotic family of antimicrobial peptides. PMID:17143619

  11. Effect of Lactococcus lactis CLFP 100 and Leuconostoc mesenteroides CLFP 196 on Aeromonas salmonicida Infection in brown trout (Salmo trutta).

    Science.gov (United States)

    Balcázar, José Luis; Vendrell, Daniel; de Blas, Ignacio; Ruiz-Zarzuela, Imanol; Múzquiz, José Luis

    2009-01-01

    Aeromonas salmonicida is the etiological agent of furunculosis in salmonid fish. This pathogen is important from an epizootic perspective because fish surviving an outbreak can remain lifelong asymptomatic carriers, serving as reservoirs of infection. As a result, the early detection and the control of infection are essential to prevent the spread of new furunculosis outbreaks. We have thus analyzed the effect of probiotic administration on the incidence of A. salmonicida in brown trout (Salmo trutta), that were subjected to temperature stress. Treatment with probiotic strains (Lactococcus lactis CLFP 100 and Leuconostoc mesenteroides CLFP 196) resulted in a higher survival rate after challenge, activation of phagocytic cells in the head kidney, and a lower rate of pathogen proliferation in the intestine as determined by real-time PCR. PMID:19556745

  12. Genetically Modified Lactococcus lactis for Delivery of Human Interleukin-10 to Dendritic Cells

    Directory of Open Access Journals (Sweden)

    Inge L. Huibregtse

    2012-01-01

    Full Text Available Interleukin-10 (IL-10 plays an indispensable role in mucosal tolerance by programming dendritic cells (DCs to induce suppressor Th-cells. We have tested the modulating effect of L. lactis secreting human IL-10 (L.  lactisIL-10 on DC function in vitro. Monocyte-derived DC incubated with L.  lactisIL-10 induced effector Th-cells that markedly suppressed the proliferation of allogenic Th-cells as compared to L. lactis. This suppressive effect was only seen when DC showed increased CD83 and CD86 expression. Furthermore, enhanced production of IL-10 was measured in both L.  lactisIL-10-derived DC and Th-cells compared to L. lactis-derived DC and Th-cells. Neutralizing IL-10 during DC-Th-cell interaction and coculturing L.  lactisIL-10-derived suppressor Th-cells with allogenic Th-cells in a transwell system prevented the induction of suppressor Th-cells. Only 130 pg/mL of bacterial-derived IL-10 and 40 times more exogenously added recombinant human IL-10 were needed during DC priming for the generation of suppressor Th-cells. The spatially restricted delivery of IL-10 by food-grade bacteria is a promising strategy to induce suppressor Th-cells in vivo and to treat inflammatory diseases.

  13. Control analysis of the role of triosephosphate isomerase in glucose metabolism in Lactococcus lactis

    DEFF Research Database (Denmark)

    Solem, Christian; Købmann, Brian Jensen; Jensen, Peter Ruhdal

    2008-01-01

    Triosephosphate isomerase (TPI), which catalyses the conversion of dihydroxyacetone phosphate (DHAP) to glyceraldehyde-3-phosphate (G3P), was studied for its control on glycolysis and mixed acid production in L. lactis subspecies lactis IL1403 and L. lactis subspecies cremoris MG1363. Strains in...... metabolites glucose-6-phosphate, fructose-1,6-bisphosphate and DHAP in the IL1403 derivatives were essentially unchanged for TPI activities from 26% to 225%. At a TPI activity of 3%, the level of DHAP increased four times. The finding that an increased level of DHAP coincides with an increase in formate...

  14. Identification of a Conserved Sequence in Flavoproteins Essential for the Correct Conformation and Activity of the NADH Oxidase NoxE of Lactococcus lactis ▿ †

    OpenAIRE

    Tachon, Sybille; Chambellon, Emilie; Yvon, Mireille

    2011-01-01

    Water-forming NADH oxidases (encoded by noxE, nox2, or nox) are flavoproteins generally implicated in the aerobic survival of microaerophilic bacteria, such as lactic acid bacteria. However, some natural Lactococcus lactis strains produce an inactive NoxE. We examined the role of NoxE in the oxygen tolerance of L. lactis in the rich synthetic medium GM17. Inactivation of noxE suppressed 95% of NADH oxidase activity but only slightly affected aerobic growth, oxidative stress resistance, and NA...

  15. Induction of a stress response in Lactococcus lactis is associated with a resistance to ribosomally active antibiotics.

    Science.gov (United States)

    Dorrian, James M; Briggs, Deborah A; Ridley, Michael L; Layfield, Robert; Kerr, Ian D

    2011-11-01

    The acquisition of multidrug resistance in bacteria underlies the failure of antimicrobial therapy, and the emergence of pathogens that are resistant to almost the entire armoury of antibiotics. Among the proteins that can mediate or contribute to the drug-resistance profile in Gram-positive bacteria is a subset of ATP-binding cassette proteins that are comprised of a tandem-repeated nucleotide-binding domain. In this study, we expressed one of these NBD(2) proteins, LmrC, in an antibiotic-sensitive Gram-positive host strain (Lactococcus lactis) and demonstrated the acquisition of resistance to ribosomally active antibiotics. Mutation of key catalytic residues suggested that the resistance profile was the result of a cellular response, rather than being a function of the NBD(2) protein itself. This observation was confirmed by 2D SDS/PAGE, which demonstrated that the expression of the NBD(2) protein induced a stress response in L. lactis. A model combining this stress response induction and the acquisition of antibiotic resistance is proposed. PMID:21848804

  16. Bidirectional cell-surface anchoring function of C-terminal repeat region of peptidoglycan hydrolase of Lactococcus lactis IL1403.

    Science.gov (United States)

    Tarahomjoo, Shirin; Katakura, Yoshio; Satoh, Eiichi; Shioya, Suteaki

    2008-02-01

    With the aim of constructing an efficient protein display system for lactic acid bacteria (LABs), the effect of fusion direction on the cell-surface binding activity of the C-terminal region of the peptidoglycan hydrolase (CPH) of Lactococcus lactis IL1403 was studied. CPH fused to the alpha-amylase (AMY) of Streptococcus bovis 148 either at its C-terminus (CPH-AMY) or at its N-terminus (AMY-CPH) was expressed intracellularly in Escherichia coli. This domain was able to direct binding of AMY to the surface of L. lactis ATCC 19435 in both constructs. However, the number of bound molecules per cell and the specific activity for starch digestion in the case of CPH-AMY were 3 and 14 times greater than those in the case of AMY-CPH, respectively. Of the LABs tested, L. lactis ATCC 19435 showed the highest binding capability for CPH-AMY, up to 6 x 10(4) molecules per cell, with a dissociation rate constant of 5.00 x 10(-5) s(-1). The binding of CPH-AMY to the surface of Lactobacillus delbrueckii ATCC 9649 cells was very stable with a dissociation rate constant of 6.96 x 10(-6) s(-1). The production of CPH-AMY in the soluble form increased 3-fold as a result of coexpression with a molecular chaperone, trigger factor. The results of this study suggest the usefulness of CPH as a bidirectional anchor protein for the production of cell-surface adhesive enzymes in E. coli. Furthermore, the importance of the fusion direction of CPH in determining cell-surface binding and enzymatic activities was shown. PMID:18343337

  17. Producción de ácido láctico por una mezcla de lactococcus lactis y streptococcus salivarius en fermentaciones en discontinuo

    OpenAIRE

    Serna Cock, Liliana; Rodríguez de Stouvenel, Aida

    2006-01-01

    Se estudió la producción de ácido láctico (AL), la conversión de sustrato (CG), y el rendimiento(Yp/s) de Lactococcus lactis, Streptococcus salivarius y una mezcla 1:1 de ambas cepas en sustrato glucosado. Lactococcus lactis se seleccionó de 20 cepas homofermentativas aisladas de cultivos de caña de azúcar variedad CC85-92 y Streptococcus salivarius se aisló de un fermento láctico comercial. En fermentaciones llevadas a cabo con la mezcla microbiana, a 32 °C con 60 gL-1 de glucosa y pH 6,0 se...

  18. Improvement of LysM-Mediated Surface Display of Designed Ankyrin Repeat Proteins (DARPins) in Recombinant and Nonrecombinant Strains of Lactococcus lactis and Lactobacillus Species

    OpenAIRE

    Zadravec, Petra; Štrukelj, Borut; Berlec, Aleš

    2015-01-01

    Safety and probiotic properties make lactic acid bacteria (LAB) attractive hosts for surface display of heterologous proteins. Protein display on nonrecombinant microorganisms is preferred for therapeutic and food applications due to regulatory requirements. We displayed two designed ankyrin repeat proteins (DARPins), each possessing affinity for the Fc region of human IgG, on the surface of Lactococcus lactis by fusing them to the Usp45 secretion signal and to the peptidoglycan-binding C ter...

  19. Transport of β-Casein-derived Peptides by the Oligopeptide Transport System Is a Crucial Step in the Proteolytic Pathway of Lactococcus lactis

    OpenAIRE

    Kunji, E. R. S.; Hagting, A; de Vries, C. J.; Juillard, V; Haandrikman, A J; Poolman, B; Konings, W. N.

    1995-01-01

    In the proteolytic pathway of Lactococcus lactis, milk proteins (caseins) are hydrolyzed extracellularly to oligopeptides by the proteinase (PrtP). The fate of these peptides, i.e. extracellular hydrolysis followed by amino acid uptake or transport followed by intracellular hydrolysis, has been addressed. Mutants have been constructed that lack a functional di-tripeptide transport system (DtpT) and/or oligopeptide transport system (Opp) but do express the P-1-type proteinase (specific for hyd...

  20. Degradation and debittering of a tryptic digest from beta-casein by aminopeptidase N from Lactococcus lactis subsp. cremoris Wg2.

    OpenAIRE

    Tan, P S; van Kessel, T A; van de Veerdonk, F.L.; Zuurendonk, P F; Bruins, A P; Konings, W. N.

    1993-01-01

    The mode of action of purified aminopeptidase N from Lactococcus lactis subsp. cremoris Wg2 on a complex peptide mixture of a tryptic digest from bovine beta-casein was analyzed. The oligopeptides produced in the tryptic digest before and after aminopeptidase N treatment were identified by analysis of the N- and C-terminal amino acid sequences and amino acid compositions of the isolated peptides and by on-line liquid chromatography-mass spectrometry. Incubation of purified peptides with amino...

  1. Bacteriocinas de Lactococcus lactis aislados de quesos asturianos: Nisina Z y Lactococina 972

    OpenAIRE

    Martínez Fernández, Beatriz

    1996-01-01

    Se ha analizado la producción de bacteriocinas en cepas de lactococcus aisladas de quesos artesanales asturianos, de este modo se han identificado productores de Nisina Z que producen la bacteriocina en leche y, además, presentan aptitudes tecnológicas adecuadas para su inclusión en un cultivo iniciador. Por otro lado, se ha descrito una nueva bacteriocina Lactococina 972, cuyo espectro de actuación se restringe al género lactococcus. Esta bacteriocina se ha purificado y se ha obtenido su ...

  2. The Transcriptional and Gene Regulatory Network of Lactococcus lactis MG1363 during Growth in Milk

    DEFF Research Database (Denmark)

    de Jong, Anne; Hansen, Morten Ejby; Kuipers, Oscar P.;

    2013-01-01

    milk. All available novel and literature-derived data were integrated into network reconstruction building blocks, which were used to reconstruct and visualize the L. lactis gene regulatory network. This network enables easy mining in the chrono-transcriptomics data. A freely available website at http...... analysis of gene expression over time showed that L. lactis adapted quickly to the environmental changes. Using upstream sequences of genes with correlated gene expression profiles, we uncovered a substantial number of putative DNA binding motifs that may be relevant for L. lactis fermentative growth in......://milkts.molgenrug.nl gives full access to all transcriptome data, to the reconstructed network and to the individual network building blocks....

  3. Production of recombinant peanut allergen Ara h 2 using Lactococcus lactis

    DEFF Research Database (Denmark)

    Glenting, J.; Poulsen, Lars K.; Kato, K.;

    2007-01-01

    Background: Natural allergen sources can supply large quantities of authentic allergen mixtures for use as immunotherapeutics. However, such extracts are complex, difficult to define, vary from batch to batch, which may lead to unpredictable efficacy and/ or unacceptable levels of side effects. The...... lactis is an attractive microorganism for use in the production of protein therapeutics. L. lactis is considered food grade, free of endotoxins, and is able to secrete the heterologous product together with few other native proteins. Hypersensitivity to peanut represents a serious allergic problem. Some...

  4. Increased D-alanylation of lipoteichoic acid and a thickened septum are main determinants in the nisin resistance mechanism of Lactococcus lactis.

    Science.gov (United States)

    Kramer, Naomi E; Hasper, Hester E; van den Bogaard, Patrick T C; Morath, Siegfried; de Kruijff, Ben; Hartung, Thomas; Smid, Eddy J; Breukink, Eefjan; Kok, Jan; Kuipers, Oscar P

    2008-06-01

    Nisin is a post-translationally modified antimicrobial peptide produced by Lactococcus lactis which binds to lipid II in the membrane to form pores and inhibit cell-wall synthesis. A nisin-resistant (Nis(R)) strain of L. lactis, which is able to grow at a 75-fold higher nisin concentration than its parent strain, was investigated with respect to changes in the cell wall. Direct binding studies demonstrated that less nisin was able to bind to lipid II in the membranes of L. lactis Nis(R) than in the parent strain. In contrast to vancomycin binding, which showed ring-like binding, nisin was observed to bind in patches close to cell-division sites in both the wild-type and the Nis(R) strains. Comparison of modifications in lipoteichoic acid of the L. lactis strains revealed an increase in d-alanyl esters and galactose as substituents in L. lactis Nis(R), resulting in a less negatively charged cell wall. Moreover, the cell wall displays significantly increased thickness at the septum. These results indicate that shielding the membrane and thus the lipid II molecule, thereby decreasing abduction of lipid II and subsequent pore-formation, is a major defence mechanism of L. lactis against nisin. PMID:18524930

  5. Características da bacteriocina produzida por Lactococcus lactis ssp. hordniae CTC 484 e seu efeito sobre Listeria monocytogenes em carne bovina Characterisation of the bacteriocin produced by Lactococcus lactis ssp. hordniae CTC 484 and the effect of this compound on Listeria monocytogenes in beef

    Directory of Open Access Journals (Sweden)

    Renata Bromberg

    2006-03-01

    Full Text Available O isolamento de linhagens de bactérias lácticas produtoras de bacteriocinas em carnes e seus produtos derivados resultou na detecção de Lactococcus lactis ssp. hordniae CTC 484, proveniente de frango. A bacteriocina inibiu não apenas uma outra bactéria láctica (Lactobacillus helveticus, mas também microorganismos patogênicos (Staphylococcus aureus, Listeria monocytogenes, Bacillus cereus, Clostridium perfringens e Enterococcus faecalis. Ela foi inativada por causa de enzimas como: alfa-quimotripsina, tripsina, pronase E, ficina, pepsina, papaína e lipase. Além disso, a bacteriocina mostrou-se termoestável, mesmo a temperaturas de autoclavagem (121°C/10 min e foi produzida em condições de armazenamento sob refrigeração. A bacteriocina mostrou-se ativa dentro de uma ampla faixa de valores de pH (2-10, porém a maior atividade ocorreu em valores menores de pH. A eficiência da linhagem CTC 484, assim como a de sua bacteriocina na redução e inibição do crescimento de Listeria monocytogenes em carne bovina estéril, foram avaliadas. Os resultados indicaram que o tratamento da carne por meio da inoculação desta bactéria contribuiu para o aumento da segurança e extensão da vida útil deste alimento.Screening for the bacteriocin production of strains of lactic acid bacteria from various meat and meat products resulted in the detection of a bacteriocin-producing Lactococcus lactis ssp. hordniae CTC 484, isolated from chicken. The bacteriocin inhibited not only closely related lactic acid bacterium (Lactobacillus helveticus, but also pathogenic microorganisms (Staphylococcus aureus, Listeria monocytogenes, Bacillus cereus, Clostridium perfringens, and Enterococcus faecalis. This compound was inactivated by alpha-chymotrypsin, trypsin, pronase E, ficin, pepsin, papain, and also by lipase. It was heat stable even at autoclaving temperature (121°C/10 min and was produced under refrigerated storage. It was also active over a wide

  6. Strains of Lactococcus lactis with a partial pyrimidine requirement show sensitivity toward aspartic acid

    DEFF Research Database (Denmark)

    Wadskov-Hansen, Steen Lyders Lerche; Martinussen, Jan

    2009-01-01

    that the partial pyrimidine requirement can be explained by a low specific activity of the pyrimidine biosynthetic enzymes. In conclusion, L. lactis LM0230 during the process of plasmid- and prophage-curing has acquired a partial pyrimidine requirement resulting in sensitivity toward aspartic acid....

  7. An exoproteome approach to monitor safety of a cheese-isolated Lactococcus lactis

    DEFF Research Database (Denmark)

    Genovese, Federica; Coïsson, Jean Daniel; Majumder, Avishek;

    2013-01-01

    . A DIGE comparative exoproteomic analysis was performed on the L. lactis 11D strain grown on glucose and the disaccharide trehalose, examined here due to its common use as lyophilization stabilizer, respectively. The experiment showed that chitinase biosynthesis was enhanced in presence of trehalose...

  8. Carbon catabolite repression and global control of the carbohydrate metabolism in Lactococcus lactis.

    NARCIS (Netherlands)

    Luesink, E.J.

    1998-01-01

    In view of the economic importance of fermented dairy products considerable scientific attention has been given to various steps of fermentation processes, including the L-lactate formation of lactic acid bacteria (de Vos, 1996). In particular, the carbohydrate metabolism of L. lactis has been the s

  9. Improved acid stress survival of Lactococcus lactis expressing the histidine decarboxylation pathway of Streptococcus thermophilus CHCC1524.

    Science.gov (United States)

    Trip, Hein; Mulder, Niels L; Lolkema, Juke S

    2012-03-30

    Degradative amino acid decarboxylation pathways in bacteria generate secondary metabolic energy and provide resistance against acid stress. The histidine decarboxylation pathway of Streptococcus thermophilus CHCC1524 was functionally expressed in the heterologous host Lactococcus lactis NZ9000, and the benefits of the newly acquired pathway for the host were analyzed. During growth in M17 medium in the pH range of 5-6.5, a small positive effect was observed on the biomass yield in batch culture, whereas no growth rate enhancement was evident. In contrast, a strong benefit for the engineered L. lactis strain was observed in acid stress survival. In the presence of histidine, the pathway enabled cells to survive at pH values as low as 3 for at least 2 h, conditions under which the host cells were rapidly dying. The flux through the histidine decarboxylation pathway in cells grown at physiological pH was under strict control of the electrochemical proton gradient (pmf) across the membrane. Ionophores that dissipated the membrane potential (ΔΨ) and/or the pH gradient (ΔpH) strongly increased the flux, whereas the presence of glucose almost completely inhibited the flux. Control of the pmf over the flux was exerted by both ΔΨ and ΔpH and was distributed over the transporter HdcP and the decarboxylase HdcA. The control allowed for a synergistic effect between the histidine decarboxylation and glycolytic pathways in acid stress survival. In a narrow pH range around 2.5 the synergism resulted in a 10-fold higher survival rate. PMID:22351775

  10. Carbon catabolite repression and global control of the carbohydrate metabolism in Lactococcus lactis.

    OpenAIRE

    Luesink, E.J.

    1998-01-01

    In view of the economic importance of fermented dairy products considerable scientific attention has been given to various steps of fermentation processes, including the L-lactate formation of lactic acid bacteria (de Vos, 1996). In particular, the carbohydrate metabolism of L. lactis has been the subject of extensive research and several genes encoding proteins involved in the central carbohydrate metabolism have been described (Llanos et al., 1992; Llanos et al., 1993; Cancilla et al., 1995...

  11. Genotypic and phenotypic diversity of Lactococcus lactis isolates from Batzos, a Greek PDO raw goat milk cheese.

    Science.gov (United States)

    Psoni, L; Kotzamanidis, C; Yiangou, M; Tzanetakis, N; Litopoulou-Tzanetaki, E

    2007-03-10

    The genotypic and phenotypic variability of 40 Lactococcus lactis isolates obtained from three cheese-making trials of Batzos cheese made one in each, winter, spring and summer was investigated. RAPD-PCR, plasmid profiling and PFGE were used to study the genetic variability and distinguish closely related isolates. Results showed a high degree of heterogeneity among strains. According to PFGE data, all strains except one were clustered together (at a similarity level of approximately 50%) with the L. lactis subsp. lactis reference strain and eleven groups of isolates consisting of 2-8 strains each were distinguished. Plasmid profiling results revealed that there were eight isolates lacking plasmids and nine having unique plasmids. Twenty-three isolates were allocated into six groups. There was an interesting similarity between the plasmid profiling groups and those formed according to PFGE. Clustering of strains according to RAPD-PCR was in agreement with results obtained by both plasmid profiling and PFGE for the majority of the strains. In addition, results obtained by molecular methods indicate a grouping of most of the strains according to the season of cheese production. All strains inhibited the growth of Escherichia coli O157:H7. Their ability to affect the growth of Yersinia enterocolitica, Staphylococcus aureus, Bacillus cereus, Listeria monocytogenes and Enterococcus faecalis was strain dependent. In 42.5% of the isolates high acidifying ability in milk after 24 h was recorded and these were isolates, mainly, from fresh cheese. The 75% of the isolates from winter cheese exhibited higher Lys- than Leu-aminopeptidase activity while the approximately 67% of the isolates from summer cheese showed higher Leu- than Lys-aminopeptidase activity. Their caseinolytic activity after growth in milk for 24 h was significant with preference for alpha(s)-casein degradation. The majority (90%) of the strains formed methanethiol from methionine and this ability was strain

  12. Industrial-scale production and purification of a heterologous protein in Lactococcus lactis using the nisin-controlled gene expression system NICE: The case of lysostaphin

    Directory of Open Access Journals (Sweden)

    Floris Esther

    2005-05-01

    Full Text Available Abstract Background The NIsin-Controlled gene Expression system NICE of Lactococcus lactis is one of the most widespread used expression systems of Gram-positive bacteria. It is used in more than 100 laboratories for laboratory-scale gene expression experiments. However, L. lactis is also a micro-organism with a large biotechnological potential. Therefore, the aim of this study was to test whether protein production in L. lactis using the NICE system can also effectively be performed at the industrial-scale of fermentation. Results Lysostaphin, an antibacterial protein (mainly against Staphylococcus aureus from S. simulans biovar. Staphylolyticus, was used as a model system. Food-grade lysostaphin expression constructs in L. lactis were grown at 1L-, 300-L and 3000-L scale and induced with nisin for lysostaphin production. The induction process was equally effective at all scales and yields of about 100 mg/L were obtained. Up-scaling was easy and required no specific effort. Furthermore, we describe a simple and effective way of downstream processing to obtain a highly purified lysostaphin, which has been used for clinical phase I trials. Conclusion This is the first example that shows that nisin-regulated gene expression in L. lactis can be used at industrial scale to produce large amounts of a target protein, such as lysostaphin. Downstream processing was simple and in a few steps produced a highly purified and active enzyme.

  13. Structure-guided engineering of Lactococcus lactis alcohol dehydrogenase LlAdhA for improved conversion of isobutyraldehyde to isobutanol

    KAUST Repository

    Liu, Xiang

    2013-03-01

    We have determined the X-ray crystal structures of the NADH-dependent alcohol dehydrogenase LlAdhA from Lactococcus lactis and its laboratory-evolved variant LlAdhA(RE1) at 1.9Å and 2.5Å resolution, respectively. LlAdhA(RE1), which contains three amino acid mutations (Y50F, I212T, and L264V), was engineered to increase the microbial production of isobutanol (2-methylpropan-1-ol) from isobutyraldehyde (2-methylpropanal). Structural comparison of LlAdhA and LlAdhA(RE1) indicates that the enhanced activity on isobutyraldehyde stems from increases in the protein\\'s active site size, hydrophobicity, and substrate access. Further structure-guided mutagenesis generated a quadruple mutant (Y50F/N110S/I212T/L264V), whose KM for isobutyraldehyde is ∼17-fold lower and catalytic efficiency (kcat/KM) is ∼160-fold higher than wild-type LlAdhA. Combining detailed structural information and directed evolution, we have achieved significant improvements in non-native alcohol dehydrogenase activity that will facilitate the production of next-generation fuels such as isobutanol from renewable resources.

  14. A food-grade fimbrial adhesin FaeG expression system in Lactococcus lactis and Lactobacillus casei.

    Science.gov (United States)

    Lu, W W; Wang, T; Wang, Y; Xin, M; Kong, J

    2016-03-01

    Enterotoxigenic Escherichia coli (ETEC) infection is the major cause of diarrhea in neonatal piglets. The fimbriae as colonizing factor in the pathogenesis of ETEC constitute a primary target for vaccination against ETEC. Lactic acid bacteria (LAB) are attractive tools to deliver antigens at the mucosal level. With the safety of genetically modified LAB in mind, a food-grade secretion vector (pALRc or pALRb) was constructed with DNA entirely from LAB, including the replicon, promoter, signal peptide, and selection marker alanine racemase gene (alr). To evaluate the feasibility of the system, the nuclease gene (nuc) from Staphylococcus aureus was used as a reporter to be expressed in both Lactococcus lactis and Lactobacillus casei. Subsequently, the extracellular secretion of the fimbrial adhesin FaeG of ETEC was confirmed by Western blot analysis. These results showed that this food-grade expression system has potential as the delivery vehicle for the safe use of genetically modified LAB for the development of vaccines against ETEC infection. PMID:26825016

  15. Biogenic amine production by Lactococcus lactis subsp. cremoris strains in the model system of Dutch-type cheese.

    Science.gov (United States)

    Flasarová, Radka; Pachlová, Vendula; Buňková, Leona; Menšíková, Anna; Georgová, Nikola; Dráb, Vladimír; Buňka, František

    2016-03-01

    The aim of this study was to compare the biogenic amine production of two starter strains of Lactococcus lactis subsp. cremoris (strains from the Culture Collection of Dairy Microorganisms - CCDM 824 and CCDM 946) with decarboxylase positive activity in a model system of Dutch-type cheese during a 90-day ripening period at 10°C. During ripening, biogenic amine and free amino acid content, microbiological characteristics and proximate chemical properties were observed. By the end of the ripening period, the putrescine content in both samples with the addition of the biogenic amine producing strain almost evened out and the concentration of putrescine was >800mg/kg. The amount of tyramine in the cheeses with the addition of the strain of CCDM 824 approached the limit of 400mg/kg by the end of ripening. In the cheeses with the addition of the strain of CCDM 946 it even exceeded 500mg/kg. In the control samples, the amount of biogenic amines was insignificant. PMID:26471528

  16. Producción de ácido láctico por una mezcla de Lactococcus lactis y Streptococcus salivarius en fermentaciones en discontinuo Lactic acid production from a mixture of cultures of Lactococcus lactis and Streptococcus salivarius using batch fermentation

    OpenAIRE

    Rodríguez de Stouvenel Aida; Serna Cock Liliana

    2005-01-01

    Se estudió la producción de ácido láctico (AL), la conversión de sustrato (CG), y el rendimiento(Yp/s) de Lactococcus lactis, Streptococcus salivarius y una mezcla 1:1 de ambas cepas en sustrato glucosado. Lactococcus lactis se seleccionó de 20 cepas homofermentativas aisladas de cultivos de caña de azúcar variedad CC85-92 y Streptococcus salivarius se aisló de un fermento láctico comercial. En fermentaciones llevadas a cabo con la mezcla microbiana, a 32 °C con 60 gL-1 de glucosa y pH 6,0 se...

  17. Two Lactococcus lactis thioredoxin paralogues play different roles in responses to arsenate and oxidative stress

    DEFF Research Database (Denmark)

    Efler, Petr; Kilstrup, Mogens; Johnsen, Stig;

    2015-01-01

    Thioredoxin (Trx) maintains intracellular thiol groups in a reduced state and is involved in a wide range of cellular processes, including ribonucleotide reduction, sulphur assimilation, oxidative stress responses and arsenate detoxification. The industrially important lactic acid bacterium...

  18. Lactococcus lactis and Lactobacillus sakei as bio-protective culture to eliminate Leuconostoc mesenteroides spoilage and improve the shelf life and sensorial characteristics of commercial cooked bacon.

    Science.gov (United States)

    Comi, Giuseppe; Andyanto, Debbie; Manzano, Marisa; Iacumin, Lucilla

    2016-09-01

    Cooked bacon is a typical Italian meat product. After production, cooked bacon is stored at 4 ± 2 °C. During storage, the microorganisms that survived pasteurisation can grow and produce spoilage. For the first time, we studied the cause of the deterioration in spoiled cooked bacon compared to unspoiled samples. Moreover, the use of bio-protective cultures to improve the quality of the product and eliminate the risk of spoilage was tested. The results show that Leuconostoc mesenteroides is responsible for spoilage and produces a greening colour of the meat, slime and various compounds that result from the fermentation of sugars and the degradation of nitrogen compounds. Finally, Lactococcus lactis spp. lactis and Lactobacillus sakei were able to reduce the risk of Leuconostoc mesenteroides spoilage. PMID:27217354

  19. Integration and gene replacement in the Lactococcus lactis lac operon: induction of a cryptic phospho-beta-glucosidase in LacG-deficient strains.

    OpenAIRE

    Simons, G.; Nijhuis, M.; de Vos, W M

    1993-01-01

    Insertions, replacement mutations, and deletions were introduced via single or double crossover recombination into the lacE (enzyme IIlac) and lacG (phospho-beta-galactosidase) genes of the Lactococcus lactis chromosomal lacABCDFEGX operon. LacG production was abolished in strains missing the lacG gene or carrying multicopy insertions in the lacE gene that affected expression of the lacG gene. However, these LacG-deficient strains could still ferment lactose slowly and were found to contain a...

  20. Exopolysaccharide Biosynthesis in Lactococcus lactis NIZO B40: Functional Analysis of the Glycosyltransferase Genes Involved in Synthesis of the Polysaccharide Backbone

    OpenAIRE

    Kranenburg, Richard van; van Swam, Iris I.; Marugg, Joey D.; Kleerebezem, Michiel; de Vos, Willem M.

    1999-01-01

    We used homologous and heterologous expression of the glycosyltransferase genes of the Lactococcus lactis NIZO B40 eps gene cluster to determine the activity and substrate specificities of the encoded enzymes and established the order of assembly of the trisaccharide backbone of the exopolysaccharide repeating unit. EpsD links glucose-1-phosphate from UDP-glucose to a lipid carrier, EpsE and EpsF link glucose from UDP-glucose to lipid-linked glucose, and EpsG links galactose from UDP-galactos...

  1. The crystal structure of Lactococcus lactis dihydroorotate dehydrogenase A complexed with the enzyme reaction product throws light on its enzymatic function

    DEFF Research Database (Denmark)

    Rowland, Paul; Bjørnberg, Olof; Nielsen, Finn S.; Jensen, Kaj Frank; Larsen, Sine

    1998-01-01

    Dihydroorotate dehydrogenases (DHODs) catalyze the oxidation of (S)-dihydroorotate to orotate, the fourth step and only redox reaction in the de novo biosynthesis of pyrimidine nucleotides. A description is given of the crystal structure of Lactococcus lactis dihydroorotate dehydrogenase A (DHODA......) complexed with the product of the enzyme reaction orotate. The structure of the complex to 2.0 A resolution has been compared with the structure of the native enzyme. The active site of DHODA is known to contain a water filled cavity buried beneath a highly conserved and flexible loop. In the complex the...

  2. Adaptation of Lactococcus lactis to high growth temperature leads to a dramatic increase in acidification rate

    DEFF Research Database (Denmark)

    Chen, Jun; Shen, Jing; Hellgren, Lars;

    2015-01-01

    temperature. At the maximal permissive temperature for the wild-type, 38 °C, TM29 grows 33% faster and has a 12% higher specific lactate production rate than its parent MG1363, which results in fast lactate accumulation. Genome sequencing was used to reveal the mutations accumulated, most of which were shown...... to affect thermal tolerance. Of the mutations with more pronounced effects, two affected expression of single proteins (chaperone; riboflavin transporter), two had pleiotropic effects (RNA polymerase) which changed the gene expression profile, and one resulted in a change in the coding sequence of...... CDP-diglyceride synthase. A large deletion containing 10 genes was also found to affect thermal tolerance significantly. With this study we demonstrate a simple approach to obtain non-GMO derivatives of the important L. lactis that possess properties desirable by the industry, e.g. thermal robustness...

  3. Production of Fibronectin Binding Protein A at the surface of Lactococcus lactis increases plasmid transfer in vitro and in vivo.

    Directory of Open Access Journals (Sweden)

    Daniela Pontes

    Full Text Available Lactococci are noninvasive lactic acid bacteria frequently used as protein delivery vectors and, more recently, as DNA delivery vehicles. We previously showed that Lactococcus lactis (LL expressing the Fibronectin-Binding Protein A of Staphylococcus aureus (LL-FnBPA+ showed higher internalization rates in vitro in Caco-2 cells than the native (wt lactococci and were able to deliver a eukaryotic Green Fluorescent Protein (GFP expression plasmid in 1% of human Caco-2 cells. Here, using the bovine beta-lactoglobulin (BLG, one of the major cow's milk allergen, and GFP we characterized the potential of LL-FnBPA+ as an in vivo DNA vaccine delivery vehicle. We first showed that the invasive strain LL-FnBPA+ carrying the plasmid pValac:BLG (LL-FnBPA+ BLG was more invasive than LL-BLG and showed the same invasivity as LL-FnBPA+. Then we demonstrated that the Caco-2 cells, co-incubated with LL-FnBPA+ BLG produced up to 30 times more BLG than the Caco-2 cells co-incubated with the non invasive LL-BLG. Using two different gene reporters, BLG and GFP, and two different methods of detection, EIA and fluorescence microscopy, we showed in vivo that: i in order to be effective, LL-FnBPA+ required a pre-coating with Fetal Calf Serum before oral administration; ii plasmid transfer occurred in enterocytes without regard to the strains used (invasive or not; iii the use of LL-FnBPA+ increased the number of mice producing BLG, but not the level of BLG produced. We thus confirmed the good potential of invasive recombinant lactic acid bacteria as DNA delivery vector in vivo.

  4. Mutations in the Lactococcus lactis Ll.LtrB group II intron that retain mobility in vivo

    Directory of Open Access Journals (Sweden)

    D'Souza Lisa M

    2002-12-01

    Full Text Available Abstract Background Group II introns are mobile genetic elements that form conserved secondary and tertiary structures. In order to determine which of the conserved structural elements are required for mobility, a series of domain and sub-domain deletions were made in the Lactococcus lactis group II intron (Ll.LtrB and tested for mobility in a genetic assay. Point mutations in domains V and VI were also tested. Results The largest deletion that could be made without severely compromising mobility was 158 nucleotides in DIVb(1–2. This mutant had a mobility frequency comparable to the wild-type Ll.LtrB intron (ΔORF construct. Hence, all subsequent mutations were done in this mutant background. Deletion of DIIb reduced mobility to approximately 18% of wild-type, while another deletion in domain II (nts 404–459 was mobile to a minor extent. Only two deletions in DI and none in DIII were tolerated. Some mobility was also observed for a DIVa deletion mutant. Of the three point mutants at position G3 in DV, only G3A retained mobility. In DVI, deletion of the branch-point nucleotide abolished mobility, but the presence of any nucleotide at the branch-point position restored mobility to some extent. Conclusions The smallest intron capable of efficient retrohoming was 725 nucleotides, comprising the DIVb(1–2 and DII(iia,b deletions. The tertiary elements found to be nonessential for mobility were alpha, kappa and eta. In DV, only the G3A mutant was mobile. A branch-point residue is required for intron mobility.

  5. Temperate phages TP901-1 and fLC3, belonging to the P335 species, apparently use different pathways for DNA injection in Lactococcus lactis subsp. cremoris 3107

    DEFF Research Database (Denmark)

    Breum, Solvej Østergaard; Neve, Horst; Heller, Knut J.; Vogensen, Finn Kvist

    2007-01-01

    Five mutant of Lactococcus lactis subsp. cremoris 3107 resistant to phage TP901-1 were obtained after treatment with ethyl methanesulfonate. Two of the mutants were also resistant to phage fLC3. The remaining three mutants were as sensitive as 3107. Mutants E46 and E100 did not adsorb the two pha...

  6. The effects of combined dietary probiotics Lactococcus lactis BFE920 and Lactobacillus plantarum FGL0001 on innate immunity and disease resistance in olive flounder (Paralichthys olivaceus).

    Science.gov (United States)

    Beck, Bo Ram; Kim, Daniel; Jeon, Jongsu; Lee, Sun-Min; Kim, Hui Kwon; Kim, Oi-Jin; Lee, Jae Il; Suh, Byung Sun; Do, Hyung Ki; Lee, Kwan Hee; Holzapfel, Wilhelm H; Hwang, Jee Youn; Kwon, Mun Gyeong; Song, Seong Kyu

    2015-01-01

    The effects of a dietary probiotic mixture containing Lactococcus (Lc.) lactis BFE920 isolated from bean sprout and autochthonous Lactobacillus (Lb.) plantarum FGL0001 originally isolated from the hindgut of olive flounder (Paralichthys olivaceus) were investigated for the purpose of improving the probiotic effects of Lc. lactis BFE920 on the olive flounder. The immunostimulatory, disease protective, and weight gain effects of Lc. lactis BFE920 were significantly improved when olive flounder (average weight 37.5±1.26 g) were fed the probiotic mixture (log10 7.0 CFU each/g feed pellet) for 30 days. Flounder fed the mixture showed improved skin mucus lysozyme activity and phagocytic activity of innate immune cells compared to flounder fed a single probiotic agent or a control diet. While the levels of neutrophil activity in flounder fed the single probiotic agent or the mixture were similar, they were significantly higher than levels in a control group. Additionally, probiotic-fed flounder showed significantly increased expressions of IL-6, IL-8, and TNF-α in the intestine compared to the control group. Following a 30-day period of being fed probiotics or a control diet, the olive flounder were challenged with an i.p. injection of Streptococcus iniae (log10 6.0 CFU/fish). The groups fed the mixed probiotics, Lc. lactis BFE920, Lb. plantarum FGL0001, and the control diet had survival rates of 55%, 45%, 35%, and 20%, respectively. Flounder fed the probiotic mixture gained 38.1±2.8% more body weight compared to flounder fed the control diet during the 30-day study period. These data strongly suggest that a mixture of Lc. lactis BFE920 and Lb. plantarum FGL0001 may serve as an immunostimulating feed additive useful for disease protection in the fish farming industry. PMID:25449382

  7. On Lactococcus lactis UL719 competitivity and nisin (Nisaplin® capacity to inhibit Clostridium difficile in a model of human colon

    Directory of Open Access Journals (Sweden)

    Christophe eLe Lay

    2015-09-01

    Full Text Available Clostridium difficile is the most frequently identified enteric pathogen in patients with nocosocomially acquired, antibiotic-associated diarrhea and pseudomembranous colitis. Although metronidazole and vancomycin were effective, an increasing number of treatment failures and recurrence of C. difficile infection are being reported. Use of probiotics, particularly metabolically active lactic acid bacteria, was recently proposed as an alternative for the medical community. The aim of this study was to assess a probiotic candidate, nisin Z-producer Lactococcus lactis UL719, competitivity and nisin (Nisaplin® capacity to inhibit C. difficile in a model of human colon. Bacterial populations was enumerated by qPCR coupled to PMA treatment. L. lactis UL719 was able to survive and proliferate under simulated human colon, did not alter microbiota composition, but failed to inhibit C. difficile. While a single dose of 19 µmol/L (5× the MIC was not sufficient to inhibit C. difficile, nisin at 76 µmol/L (20× the MIC was effective at killing the pathogen. Nisin (at 76 µmol/L caused some temporary changes in the microbiota with Gram-positive bacteria being the mostly affected. These results highlight the capacity of L. lactis UL719 to survive under simulated human colon and the efficacy of nisin as an alternative in the treatment of C. difficile infections.

  8. Obtención de microcapsulas de tamaño controlado conteniendo Lactococcus lactis, utilizando mezclas de gelanos de alto y bajo acilo

    Directory of Open Access Journals (Sweden)

    Rafael Emilio Gonzalez

    2013-12-01

    Full Text Available Título en ingles: Obtaining size-controlled microcapsules by ionic gelation with high and low acyl gellans containing Lactococcus lactisResumen: Control the diameter of microcapsules obtained with functional biopolymer is a crucial parameter in the success of food applications, since it affects the protection of microencapsulated microorganism and also in the texture of the final product. The aim of this study was to assess the obtaining of controlled size microcapsules containing Lactococcus lactis, using mixtures of high acyl gellan (HA and low acyl gellan (LA. A concentration of 0.2% (w/w gellan was employed using a simple design, generating the following mixtures: 100HA/0.0LA, 0.0HA/100LA, 25HA/75LA, 50HA/50LA and 75HA/25LA. The diameter of the microcapsules, efficiency of microencapsulation and viability of the microencapsulated microorganism were studied in function of the speed of agitation (400-800 rpm and surfactant concentration (sorbitan monooleate (0.0-0.2%v/v. The results indicated that mixtures with concentration equal or greater than 50% of HA gellan are not efficient for obtaining microcapsules, only the LA gellan and the mixture 25HA/75LA gave acceptable results. The viability of the microorganism and the efficiency of microencapsulation were descending function of the stirring speed and surfactant concentration. The microcapsules obtained had diameters not greater than 80 µm when the highest concentrations of surfactant (0.2% v/v and stirring speed (800 rpm were used, suggesting that the ionic gelation can be used to obtain microcapsules of controlled size (15-75 µm containing Lactococcus lactis with high viability (83.32% and high efficiency of microencapsulation (82.4%, which makes it feasible for use in food applications.Palabras clave: microencapsulation, high acyl gellan, low acyl gellan, ionic gelation, Lactococcus lactisSummary: Controlar el diámetro de microcápsulas obtenidas con biopolímeros funcionales es un

  9. Nisin Z Production by Lactococcus lactis subsp. cremoris WA2-67 of Aquatic Origin as a Defense Mechanism to Protect Rainbow Trout (Oncorhynchus mykiss, Walbaum) Against Lactococcus garvieae.

    Science.gov (United States)

    Araújo, Carlos; Muñoz-Atienza, Estefanía; Pérez-Sánchez, Tania; Poeta, Patrícia; Igrejas, Gilberto; Hernández, Pablo E; Herranz, Carmen; Ruiz-Zarzuela, Imanol; Cintas, Luis M

    2015-12-01

    Probiotics represent an alternative to chemotherapy and vaccination to control fish diseases, including lactococcosis caused by Lactococcus garvieae. The aims of this study were (i) to determine the in vitro probiotic properties of three bacteriocinogenic Lactococcus lactis subsp. cremoris of aquatic origin, (ii) to evaluate in vivo the ability of L. cremoris WA2-67 to protect rainbow trout (Oncorhynchus mykiss, Walbaum) against infection by L. garvieae, and (iii) to demonstrate the role of nisin Z (NisZ) production as an anti-infective mechanism. The three L. cremoris strains survived in freshwater at 18 °C for 7 days, withstood exposure to pH 3.0 and 10 % (v/v) rainbow trout bile, and showed different cell surface hydrophobicity (37.93-58.52 %). The wild-type NisZ-producer L. cremoris WA2-67 and its non-bacteriocinogenic mutant L. cremoris WA2-67 ∆nisZ were administered orally (10(6) CFU/g) to rainbow trout for 21 days and, subsequently, fish were challenged with L. garvieae CLG4 by the cohabitation method. The fish fed with the bacteriocinogenic strain L. cremoris WA2-67 reduced significantly (p fish farming to prevent lactococcosis in rainbow trout. PMID:26307018

  10. Pellet feed adsorbed with the recombinant Lactococcus lactis BFE920 expressing SiMA antigen induced strong recall vaccine effects against Streptococcus iniae infection in olive flounder (Paralichthys olivaceus).

    Science.gov (United States)

    Kim, Daniel; Beck, Bo Ram; Lee, Sun Min; Jeon, Jongsu; Lee, Dong Wook; Lee, Jae Il; Song, Seong Kyu

    2016-08-01

    The aim of this study was to develop a fish feed vaccine that provides effective disease prevention and convenient application. A lactic acid bacterium (LAB), Lactococcus lactis BFE920, was modified to express the SiMA antigen, a membrane protein of Streptococcus iniae. The antigen was engineered to be expressed under the nisin promoter, which is induced by nisin produced naturally by the host LAB. Various sizes (40 ± 3.5 g, 80 ± 2.1 g, and 221 ± 2.4 g) of olive flounder (Paralichthys olivaceus) were vaccinated by feeding the extruded pellet feed, onto which the SiMA-expressing L. lactis BFE920 (1.0 × 10(7) CFU/g) was adsorbed. Vaccine-treated feed was administered twice a day for 1 week, and priming and boosting were performed with a 1-week interval in between. The vaccinated fish had significantly elevated levels of antigen-specific serum antibodies and T cell marker mRNAs: CD4-1, CD4-2, and CD8a. In addition, the feed vaccine significantly induced T cell effector functions, such as the production of IFN-γ and activation of the transcription factor that induces its expression, T-bet. When the flounder were challenged by intraperitoneal infection and bath immersion with S. iniae, the vaccinated fish showed 84% and 82% relative percent survival (RPS), respectively. Furthermore, similar protective effects were confirmed even 3 months after vaccination in a field study (n = 4800), indicating that this feed vaccine elicited prolonged duration of immunopotency. In addition, the vaccinated flounder gained 21% more weight and required 16% less feed to gain a unit of body weight compared to the control group. The data clearly demonstrate that the L. lactis BFE920-SiMA feed vaccine has strong protective effects, induces prolonged vaccine efficacy, and has probiotic effects. In addition, this LAB-based fish feed vaccine can be easily used to target many different pathogens of diverse fish species. PMID:27302864

  11. The ltp gene of temperate Streptococcus thermophilus phage TP-J34 confers superinfection exclusion to Streptococcus thermophilus and Lactococcus lactis

    International Nuclear Information System (INIS)

    The ltp gene, located within the lysogeny module of temperate Streptococcus thermophilus phage TP-J34, has been shown to be expressed in lysogenic strain S. thermophilus J34. It codes for a lipoprotein, as demonstrated by inhibition of cleavage of the signal sequence by globomycin. Exposure of Ltp on the surface of Lactococcus lactis protoplasts bearing a plasmid-encoded copy of ltp has been demonstrated by immunogold labeling and electron microscopy. Expression of ltp in prophage- and plasmid-cured S. thermophilus J34-6f interfered with TP-J34 infection. While plating efficiency was reduced by a factor of about 40 and lysis of strain J34-6f in liquid medium was delayed considerably, phage adsorption was not affected at all. Intracellular accumulation of phage DNA was shown to be inhibited by Ltp. This indicates interference of Ltp with infection at the stage of triggering DNA release and injection into the cell, indicating a role of Ltp in superinfection exclusion. Expression of ltp in L. lactis Bu2-60 showed that the same superinfection exclusion mechanism was strongly effective against phage P008, a member of the lactococcal 936 phage species: no plaque-formation was detectable with even 109 phage per ml applied, and lysis in liquid medium did not occur. In Lactococcus also, Ltp apparently inhibited phage DNA release and/or injection. Ltp appears to be a member of a family of small, secreted proteins with a 42 amino acids repeat structure encoded by genes of Gram-positive bacteria. Some of these homologous genes are part of the genomes of prophages

  12. Display of the Viral Epitopes on Lactococcus lactis: A Model for Food Grade Vaccine against EV71

    Directory of Open Access Journals (Sweden)

    Nadimpalli Ravi S. Varma

    2013-01-01

    Full Text Available In this study, we have developed a system for display of antigens of Enterovirus type 71 (EV71 on the cell surface of L. lactis. The viral capsid protein (VP1 gene from a local viral isolate was utilized as the candidate vaccine for the development of oral live vaccines against EV71 using L. lactis as a carrier. We expressed fusion proteins in E. coli and purified fusion proteins were incubated with L. lactis. We confirmed that mice orally fed with L. lactis displaying these fusion proteins on its surface were able to mount an immune response against the epitopes of EV71. This is the first example of an EV71 antigen displayed on the surface of a food grade organism and opens a new perspective for alternative vaccine strategies against the EV71. We believe that the method of protein docking utilized in this study will allow for more flexible presentations of short peptides and proteins on the surface of L. lactis to be useful as a delivery vehicle.

  13. Shigella IpaB and IpaD displayed on L. lactis bacterium-like particles induce protective immunity in adult and infant mice.

    Science.gov (United States)

    Heine, Shannon J; Franco-Mahecha, Olga L; Chen, Xiaotong; Choudhari, Shyamal; Blackwelder, William C; van Roosmalen, Maarten L; Leenhouts, Kees; Picking, Wendy L; Pasetti, Marcela F

    2015-08-01

    Shigella spp. are among the enteric pathogens with the highest attributable incidence of moderate-to-severe diarrhea in children under 5 years of age living in endemic areas. There are no vaccines available to prevent this disease. In this work, we investigated a new Shigella vaccine concept consisting of nonliving, self-adjuvanted, Lactococcus lactis bacterium-like particles (BLP) displaying Shigella invasion plasmid antigen (Ipa) B and IpaD and examined its immunogenicity and protective efficacy in adult and newborn/infant mice immunized via the nasal route. Unique advantages of this approach include the potential for broad protection due to the highly conserved structure of the Ipas and the safety and practicality of a probiotic-based mucosal/adjuvant delivery platform. Immunization of adult mice with BLP-IpaB and BLP-IpaD (BLP-IpaB/D) induced high levels of Ipa-specific serum IgG and stool IgA in a dose-dependent manner. Immune responses and protection were enhanced by BLP delivery. Vaccine-induced serum antibodies exhibited opsonophagocytic and cytotoxic neutralizing activity, and IpaB/D IgG titers correlated with increased survival post-challenge. Ipa-specific antibody secreting cells were detected in nasal tissue and lungs, as well as IgG in bronchoalveolar lavage. Bone marrow cells produced IpaB/D-specific antibodies and contributed to protection after adoptive transfer. The BLP-IpaB/D vaccine conferred 90% and 80% protection against S. flexneri and S. sonnei, respectively. Mice immunized with BLP-IpaB/D as newborns also developed IpaB and IpaD serum antibodies; 90% were protected against S. flexneri and 44% against S. sonnei. The BLP-IpaB/D vaccine is a promising candidate for safe, practical and potentially effective immunization of children against shigellosis. PMID:25776843

  14. Antibacterial activity and immunomodulatory effects on a bovine mammary epithelial cell line exerted by nisin A-producing Lactococcus lactis strains.

    Science.gov (United States)

    Malvisi, M; Stuknytė, M; Magro, G; Minozzi, G; Giardini, A; De Noni, I; Piccinini, R

    2016-03-01

    Twenty-nine strains of mastitis pathogens were used to study the antibacterial activity of the cell-free supernatants (CFS) of 25 strains of Lactococcus lactis ssp. lactis. Out of the tested strains, only the CFS of L. lactis LL11 and SL153 were active, inhibiting and killing most of the pathogens. By means of ultra-performance liquid chromatography/high resolution mass spectrometry, they were shown to produce nisin A, a class I bacteriocin. A variable sensitivity to nisin A-containing CFS was observed among Streptococcus uberis and Enterococcus faecalis strains. Nonetheless, Streptococcus agalactiae, Strep. uberis, and E. faecalis displayed high minimum inhibitory concentration values, reaching 384 arbitrary units/mL. Interestingly, the minimum inhibitory values and the bactericidal concentrations were almost identical among them for each of the 2 stains, LL11 and SL153. Staphylococci were, on average, less sensitive than streptococci, but the 2 CFS inhibited and killed, at different dilutions, strains of methicillin-resistant Staphylococcus aureus. The immune response to nisin A-containing CFS was tested using the bovine mammary epithelial cell line BME-UV1. Application of CFS did not damage epithelial integrity, as demonstrated by the higher activity of N-acetyl-β-d-glucosaminidase (NAGase) and lysozyme inside the cells, in both treated and control samples. On the other hand, the increase of released NAGase after 15 to 24h of treatment with LL11 or SL153 live cultures demonstrated an inflammatory response of epithelial cells. Similarly, a significantly higher lysozyme activity was detected in the cells treated with LL11 live culture confirming the stimulation of lysosomal activity. The treatment of epithelial cells with SL153 live culture induced a significant tumor necrosis factor-α downregulation in the cells, but did not influence IL-8 expression. The control of tumor necrosis factor-α release could be an interesting approach to reduce the symptoms linked

  15. Lactate dehydrogenase has no control on lactate production but has a strong negative control on formate production in Lactococcus lactis

    DEFF Research Database (Denmark)

    Andersen, H.W.; Pedersen, M.B.; Hammer, Karin;

    2001-01-01

    enhanced in the strain deleted for lactate dehydrogenase. What is more surprising is that the enzyme had a strong negative control (C- LDH(F1)J=-1.3) on the flux to formate at the wild-type level of lactate dehydrogenase. Furthermore, we showed that L. lactis has limited excess of capacity of lactate...

  16. Influence of extracellular pH on growth, viability, cell size, acidification activity, and intracellular pH of Lactococcus lactis in batch fermentations.

    Science.gov (United States)

    Hansen, Gunda; Johansen, Claus Lindvald; Marten, Gunvor; Wilmes, Jacqueline; Jespersen, Lene; Arneborg, Nils

    2016-07-01

    In this study, we investigated the influence of three extracellular pH (pHex) values (i.e., 5.5, 6.5, and 7.5) on the growth, viability, cell size, acidification activity in milk, and intracellular pH (pHi) of Lactococcus lactis subsp. lactis DGCC1212 during pH-controlled batch fermentations. A universal parameter (e.g., linked to pHi) for the description or prediction of viability, specific acidification activity, or growth behavior at a given pHex was not identified. We found viability as determined by flow cytometry to remain high during all growth phases and irrespectively of the pH set point. Furthermore, regardless of the pHex, the acidification activity per cell decreased over time which seemed to be linked to cell shrinkage. Flow cytometric pHi determination demonstrated an increase of the averaged pHi level for higher pH set points, while the pH gradient (pHi-pHex) and the extent of pHi heterogeneity decreased. Cells maintained positive pH gradients at a low pHex of 5.5 and even during substrate limitation at the more widely used pHex 6.5. Moreover, the strain proved able to grow despite small negative or even absent pH gradients at a high pHex of 7.5. The larger pHi heterogeneity at pHex 5.5 and 6.5 was associated with more stressful conditions resulting, e.g., from higher concentrations of non-dissociated lactic acid, while the low pHi heterogeneity at pHex 7.5 most probably corresponded to lower concentrations of non-dissociated lactic acid which facilitated the cells to reach the highest maximum active cell counts of the three pH set points. PMID:27020293

  17. Effects of dietary supplementation of Lactobacillus rhamnosus or/and Lactococcus lactis on the growth, gut microbiota and immune responses of red sea bream, Pagrus major.

    Science.gov (United States)

    Dawood, Mahmoud A O; Koshio, Shunsuke; Ishikawa, Manabu; Yokoyama, Saichiro; El Basuini, Mohammed F; Hossain, Md Sakhawat; Nhu, Truong H; Dossou, Serge; Moss, Amina S

    2016-02-01

    Pagrus major fingerlings (3·29 ± 0·02 g) were fed with basal diet (control) supplemented with Lactobacillus rhamnosus (LR), Lactococcus lactis (LL), and L. rhamnosus + L. lactis (LR + LL) at 10(6) cell g(-1) feed for 56 days. Feeding a mixture of LR and LL significantly increased feed utilization (FER and PER), intestine lactic acid bacteria (LAB) count, plasma total protein, alternative complement pathway (ACP), peroxidase, and mucus secretion compared with the other groups (P < 0.05). Serum lysozyme activity (LZY) significantly increased in LR + LL when compared with the control group. Additionally, fish fed the LR + LL diet showed a higher growth performance (Fn wt, WG, and SGR) and protein digestibility than the groups fed an individual LR or the control diet. Superoxide dismutase (SOD) significantly increased in LR and LR + LL groups when compared with the other groups. Moreover, the fish fed LR or LL had better improvement (P < 0.05) in growth, feed utilization, body protein and lipid contents, digestibility coefficients (dry matter, protein, and lipid), protease activity, total intestine and LAB counts, hematocrit, total plasma protein, biological antioxidant potential, ACP, serum and mucus LZY and bactericidal activities, peroxidase, SOD, and mucus secretion than the control group. Interestingly, fish fed diets with LR + LL showed significantly lower total cholesterol and triglycerides when compared with the other groups (P < 0.05). These data strongly suggest that a mixture of LR and LL probiotics may serve as a healthy immunostimulating feed additive in red sea bream aquaculture. PMID:26766177

  18. A highly conserved DNA replication module from Streptococcus thermophilus phages is similar in sequence and topology to a module from Lactococcus lactis phages.

    Science.gov (United States)

    Desiere, F; Lucchini, S; Bruttin, A; Zwahlen, M C; Brüssow, H

    1997-08-01

    A highly conserved DNA region extending over 5 kb was observed in Streptococcus thermophilus bacteriophages. Comparative sequencing of one temperate and 26 virulent phages demonstrated in the most extreme case an 18% aa difference for a predicted protein, while the majority of the phages showed fewer, if any aa changes. The relative degree of aa conservation was not homogeneous over the DNA segment investigated. Sequence analysis of the conserved segment revealed genes possibly involved in DNA transactions. Three predicted proteins (orf 233, 443, and 382 gene product (gp)) showed nucleoside triphosphate binding motifs. Orf 443 gp showed in addition a DEAH box motif, characteristically found in a subgroup of helicases, and a variant zinc finger motif known from a phage T7 helicase/primase. Tree analysis classified orf 443 gp as a distant member of the helicase superfamily. Orf 382 gp showed similarity to putative plasmid DNA primases. Downstream of orf 382 a noncoding repeat region was identified that showed similarity to a putative minus origin from a cryptic S. thermophilus plasmid. Four predicted proteins showed not only high degrees of aa identity (34 to 63%) with proteins from Lactococcus lactis phages, but their genes showed a similar topological organization. We interpret this as evidence for a horizontal gene transfer event between phages of the two bacterial genera in the distant past. PMID:9268169

  19. Oral delivery of glutamic acid decarboxylase (GAD)-65 and IL10 by Lactococcus lactis reverses diabetes in recent-onset NOD mice.

    Science.gov (United States)

    Robert, Sofie; Gysemans, Conny; Takiishi, Tatiana; Korf, Hannelie; Spagnuolo, Isabella; Sebastiani, Guido; Van Huynegem, Karolien; Steidler, Lothar; Caluwaerts, Silvia; Demetter, Pieter; Wasserfall, Clive H; Atkinson, Mark A; Dotta, Francesco; Rottiers, Pieter; Van Belle, Tom L; Mathieu, Chantal

    2014-08-01

    Growing insight into the pathogenesis of type 1 diabetes (T1D) and numerous studies in preclinical models highlight the potential of antigen-specific approaches to restore tolerance efficiently and safely. Oral administration of protein antigens is a preferred method for tolerance induction, but degradation during gastrointestinal passage can impede such protein-based therapies, reducing their efficacy and making them cost-ineffective. To overcome these limitations, we generated a tolerogenic bacterial delivery technology based on live Lactococcus lactis (LL) bacteria for controlled secretion of the T1D autoantigen GAD65370-575 and the anti-inflammatory cytokine interleukin-10 in the gut. In combination with short-course low-dose anti-CD3, this treatment stabilized insulitis, preserved functional β-cell mass, and restored normoglycemia in recent-onset NOD mice, even when hyperglycemia was severe at diagnosis. Combination therapy did not eliminate pathogenic effector T cells, but increased the presence of functional CD4(+)Foxp3(+)CD25(+) regulatory T cells. These preclinical data indicate a great therapeutic potential of orally administered autoantigen-secreting LL for tolerance induction in T1D. PMID:24677716

  20. Lactococcus lactis TrxD represents a subgroup of thioredoxins prevalent in Gram-positive bacteria containing WCXDC active site motifs

    DEFF Research Database (Denmark)

    Björnberg, Olof; Efler, Petr; Epie, Denis Ebong;

    2014-01-01

    Three protein disulfide reductases of the thioredoxin superfamily from the industrially important Gram-positive Lactococcus lactis (LlTrxA, LlTrxD and LlNrdH) are compared to the "classical" thioredoxin from Escherichia coil (EcTrx1). LlTrxA resembles EcTrx1 with a WCGPC active site motif and other...... key residues conserved. By contrast, LlTrxD is more distantly related and contains a WCGDC motif. Bioinformatics analysis suggests that LlTrxD represents a subgroup of thioredoxins from Gram-positive bacteria. LlNrdH is a glutaredoxin-like electron donor for ribonucleotide reductase class Ib. Based on...... capacity to reduce insulin disulfides and their exposed active site thiol is alkylated at a similar rate at pH 7.0. LlTrxD on the other hand, is alkylated by iodoacetamide at almost 100 fold higher rate and shows no activity towards insulin disulfides. LlTrxA, LlTrxD and L1NrdH are all efficiently reduced...

  1. Therapeutic efficacy of oral immunization with a non-genetically modified Lactococcus lactis-based vaccine CUE-GEM induces local immunity against Helicobacter pylori infection.

    Science.gov (United States)

    Liu, Wei; Tan, Zhoulin; Xue, Jinfeng; Luo, Wenjin; Song, Hui; Lv, Xiaobo; Zheng, Tianjing; Xi, Tao; Xing, Yingying

    2016-07-01

    The gastric bacterial pathogen Helicobacter pylori persistently colonizes the gastric mucosa of humans and plays a critical role in the development of gastritis, peptic ulceration and gastric adenocarcinoma. Consequently, the eradication of H. pylori might contribute to the prevention of H. pylori-associated gastric diseases. In this study, a multi-epitope vaccine CTB-UE (CUE) was displayed on the surface of non-genetically modified Lactococcus lactis particles (GEM) to enhance immunogenicity. This particulate vaccine CUE-GEM induced serum and mucosal specific antibody responses against native H. pylori urease and provided potent protection to eliminate H. pylori colonization and relieve gastritis in an H. pylori-infected BALB/c mouse model. The immuno-protective mechanisms are highly associated with CD4(+) Th cell-mediated and humoral immunity, especially local immunity. There might be two main aspects of this association. One aspect is related to the suppression of urease activity by promotion of the production of specific mucosal neutralizing antibody. The other aspect is correlated with alleviating gastritis by regulating the gastric pro-inflammatory cytokine profile, especially IFN-γ and IL-17. These results demonstrated that conjugating antigen vaccines with GEM particles could lead to promising oral therapeutic vaccine formulations against H. pylori infection. PMID:26846746

  2. Effects of synthetic cohesin-containing scaffold protein architecture on binding dockerin-enzyme fusions on the surface of Lactococcus lactis

    Directory of Open Access Journals (Sweden)

    Wieczorek Andrew S

    2012-12-01

    Full Text Available Abstract Background The microbial synthesis of fuels, commodity chemicals, and bioactive compounds necessitates the assemblage of multiple enzyme activities to carry out sequential chemical reactions, often via substrate channeling by means of multi-domain or multi-enzyme complexes. Engineering the controlled incorporation of enzymes in recombinant protein complexes is therefore of interest. The cellulosome of Clostridium thermocellum is an extracellular enzyme complex that efficiently hydrolyzes crystalline cellulose. Enzymes interact with protein scaffolds via type 1 dockerin/cohesin interactions, while scaffolds in turn bind surface anchor proteins by means of type 2 dockerin/cohesin interactions, which demonstrate a different binding specificity than their type 1 counterparts. Recombinant chimeric scaffold proteins containing cohesins of different specificity allow binding of multiple enzymes to specific sites within an engineered complex. Results We report the successful display of engineered chimeric scaffold proteins containing both type 1 and type 2 cohesins on the surface of Lactococcus lactis cells. The chimeric scaffold proteins were able to form complexes with the Escherichia coli β-glucuronidase fused to either type 1 or type 2 dockerin, and differences in binding efficiencies were correlated with scaffold architecture. We used E. coli β-galactosidase, also fused to type 1 or type 2 dockerins, to demonstrate the targeted incorporation of two enzymes into the complexes. The simultaneous binding of enzyme pairs each containing a different dockerin resulted in bi-enzymatic complexes tethered to the cell surface. The sequential binding of the two enzymes yielded insights into parameters affecting assembly of the complex such as protein size and position within the scaffold. Conclusions The spatial organization of enzymes into complexes is an important strategy for increasing the efficiency of biochemical pathways. In this study

  3. Activation of mRNA translation by phage protein and low temperature: the case of Lactococcus lactis abortive infection system AbiD1

    Directory of Open Access Journals (Sweden)

    Ehrlich S Dusko

    2009-01-01

    Full Text Available Abstract Background Abortive infection (Abi mechanisms comprise numerous strategies developed by bacteria to avoid being killed by bacteriophage (phage. Escherichia coli Abis are considered as mediators of programmed cell death, which is induced by infecting phage. Abis were also proposed to be stress response elements, but no environmental activation signals have yet been identified. Abis are widespread in Lactococcus lactis, but regulation of their expression remains an open question. We previously showed that development of AbiD1 abortive infection against phage bIL66 depends on orf1, which is expressed in mid-infection. However, molecular basis for this activation remains unclear. Results In non-infected AbiD1+ cells, specific abiD1 mRNA is unstable and present in low amounts. It does not increase during abortive infection of sensitive phage. Protein synthesis directed by the abiD1 translation initiation region is also inefficient. The presence of the phage orf1 gene, but not its mutant AbiD1R allele, strongly increases abiD1 translation efficiency. Interestingly, cell growth at low temperature also activates translation of abiD1 mRNA and consequently the AbiD1 phenotype, and occurs independently of phage infection. There is no synergism between the two abiD1 inducers. Purified Orf1 protein binds mRNAs containing a secondary structure motif, identified within the translation initiation regions of abiD1, the mid-infection phage bIL66 M-operon, and the L. lactis osmC gene. Conclusion Expression of the abiD1 gene and consequently AbiD1 phenotype is specifically translationally activated by the phage Orf1 protein. The loss of ability to activate translation of abiD1 mRNA determines the molecular basis for phage resistance to AbiD1. We show for the first time that temperature downshift also activates abortive infection by activation of abiD1 mRNA translation.

  4. Metabolic and Transcriptional Analysis of Acid Stress in Lactococcus lactis , with a Focus on the Kinetics of Lactic Acid Pools

    OpenAIRE

    Carvalho, Ana Lúcia; David L Turner; Fonseca, Luís L.; Solopova, Ana; Catarino, Teresa; Kuipers, Oscar P; Voit, Eberhard O.; Neves, Ana Rute; Santos, Helena

    2013-01-01

    The effect of pH on the glucose metabolism of non-growing cells of L. lactis MG1363 was studied by in vivo NMR in the range 4.8 to 6.5. Immediate pH effects on glucose transporters and/or enzyme activities were distinguished from transcriptional/translational effects by using cells grown at the optimal pH of 6.5 or pre-adjusted to low pH by growth at 5.1. In cells grown at pH 5.1, glucose metabolism proceeds at a rate 35% higher than in non-adjusted cells at the same pH. Besides the upregulat...

  5. The simultaneous biosynthesis and uptake of amino acids by Lactococcus lactis studied by C-13-labeling experiments

    DEFF Research Database (Denmark)

    Jensen, N.B.S.; Christensen, B.; Nielsen, Jette;

    2002-01-01

    Uniformly C-13 labeled glucose was fed to a lactic acid bacterium growing on a defined medium supplemented with all proteinogenic amino acids except glutamate. Aspartate stemming from the protein pool and from the extracellular medium was enriched with C-13 disclosing a substantial de novo biosyn...

  6. Phenotypical analysis of the Lactobacillus rhamnosus GG fimbrial spaFED operon: surface expression and functional characterization of recombinant SpaFED pili in Lactococcus lactis.

    Directory of Open Access Journals (Sweden)

    Johanna Rintahaka

    Full Text Available A noticeable genomic feature of many piliated Gram-positive bacterial species is the presence of more than one pilus-encoding operon. Paradigmatically, the gut-adapted Lactobacillus rhamnosus GG strain contains two different fimbrial operons in its genome. However, whereas one of these operons (called spaCBA is encoding for the functionally mucus-/collagen-binding SpaCBA pilus, for the other operon (called spaFED any native expression of the SpaFED-called pili is still the subject of some uncertainty. Irrespective of such considerations, we decided it would be of relevance or interest to decipher the gross structure of this pilus type, and as well assess its functional capabilities for cellular adhesion and immunostimulation. For this, and by following the approach we had used previously to explicate the immuno-properties of SpaCBA pili, we constructed nisin-inducible expression clones producing either wild-type or SpaF pilin-deleted surface-assembled L. rhamnosus GG SpaFED pili on Lactococcus lactis cells. Using these piliated lactococcal constructs, we found that the pilin-polymerized architecture of a recombinant-produced SpaFED pilus coincides with sequence-based functional predictions of the related pilins, and in fact is prototypical of those other sortase-dependent pilus-like structures thus far characterized for piliated Gram-positive bacteria. Moreover, we confirmed that among the different pilin subunits encompassing spaFED operon-encoded pili, the SpaF pilin is a main adhesion determinant, and when present in the assembled structure can mediate pilus binding to mucus, certain extracellular matrix proteins, and different gut epithelial cell lines. However, somewhat unexpectedly, when recombinant SpaFED pili are surface-attached, we found that they could not potentiate the existing lactococcal cell-induced immune responses so elicited from intestinal- and immune-related cells, but rather instead, they could dampen them. Accordingly, we

  7. CHARACTERIZATION OF LACTOCOCCUS STRAINS AND THEIR USING IN DAIRY TECHNOLOGY

    Directory of Open Access Journals (Sweden)

    Gabriel Greif

    2012-02-01

    Full Text Available Lactococcus lactis species is one of the most important groups of lactic acid bacteria that are used in the dairy industry. Lactococci are generally found on plants and the skins of animals. Special interest is placed on the study of Lactococcus lactis ssp. lactis and Lactococcus lactis ssp. cremoris, as they are the strains used as starter cultures in industrial dairy fermentation. The major functions of this species in dairy fermentation are the production of lactic acid, formation of flavour and aroma compounds, development of ripened cheese texture and antimicrobial activity against spoilage bacteria and moulds.doi:10.5219/162

  8. EFSA Panel on Dietetic Products, Nutrition and Allergies (NDA) Scientific Opinion on the substantiation of a health claim related to a combination of Bifidobacterium longum LA 101, Lactobacillus helveticus LA 102, Lactococcus lactis LA 103 and Streptococcus

    DEFF Research Database (Denmark)

    Tetens, Inge

    substantiation of a health claim related to a combination of Bifidobacterium longum LA 101, Lactobacillus helveticus LA 102, Lactococcus lactis LA 103 and Streptococcus thermophilus LA 104 and improves stools frequency. The food that is the subject of the health claim is a combination of B. longum LA 101, L...... and effect relationship cannot be established between the consumption of a combination of B. longum LA 101, L. helveticus LA 102, L. lactis LA 103 and S. thermophilus LA 104 and improves stool frequency. © European Food Safety Authority, 2013...

  9. EFSA Panel on Dietetic Products, Nutrition and Allergies (NDA); Scientific Opinion on the substantiation of a health claim related to a combination of Bifidobacterium logum LA 10, Lactobacillus helveticus LA 102, Lactococcus lactis LA 103 and Streptococcus thermophilus LA 104 and reducing

    DEFF Research Database (Denmark)

    Tetens, Inge

    substantiation of a health claim related to a combination of Bifidobacterium longum LA 101, Lactobacillus helveticus LA 102, Lactococcus lactis LA 103 and Streptococcus thermophilus LA 104 and reducing intestinal discomfort. The food that is the subject of the health claim is a combination of B. longum LA 101, L...... and effect relationship cannot be established between the consumption of a combination of B. longum LA 101, L. helveticus LA 102, L. lactis LA 103, and S. thermophilus LA 104 and reducing intestinal discomfort. © European Food Safety Authority, 2013...

  10. Putrescine production by Lactococcus lactis subsp. cremoris CECT 8666 is reduced by NaCl via a decrease in bacterial growth and the repression of the genes involved in putrescine production.

    Science.gov (United States)

    Del Rio, Beatriz; Redruello, Begoña; Ladero, Victor; Fernandez, Maria; Martin, Maria Cruz; Alvarez, Miguel A

    2016-09-01

    The reduction of NaCl in food is a public health priority; high NaCl intakes have been associated with serious health problems. However, it is reported that reducing the NaCl content of cheeses may lead to an increase in the content of biogenic amines (BAs). The present work examines the effect of NaCl on the accumulation of putrescine (one of the BAs often detected at high concentration in cheese) in experimental Cabrales-like cheeses containing Lactococcus lactis subsp. cremoris CECT 8666, a dairy strain that catabolises agmatine to putrescine via the agmatine deiminase (AGDI) pathway. The genes responsible for this pathway are grouped in the AGDI cluster. This comprises a regulatory gene (aguR) (transcribed independently), followed by the catabolic genes that together form an operon (aguBDAC). Reducing the NaCl concentration of the cheese led to increased putrescine accumulation. In contrast, increasing the NaCl concentration of both pH-uncontrolled and pH-controlled (pH 6) cultures of L. lactis subsp. cremoris CECT 8666 significantly inhibited its growth and the production of putrescine. Such production appeared to be inhibited via a reduction in the transcription of the aguBDAC operon; no effect on the transcription of aguR was recorded. The present results suggest that low-sodium cheeses are at risk of accumulating higher concentrations of putrescine. PMID:27218410

  11. System using tandem repeats of the cA peptidoglycan-binding domain from Lactococcus lactis for display of both N- and C-terminal fusions on cell surfaces of lactic acid bacteria.

    Science.gov (United States)

    Okano, Kenji; Zhang, Qiao; Kimura, Sakurako; Narita, Junya; Tanaka, Tsutomu; Fukuda, Hideki; Kondo, Akihiko

    2008-02-01

    Here, we established a system for displaying heterologous protein to the C terminus of the peptidoglycan-binding domain (cA domain) of AcmA (a major autolysin from Lactococcus lactis). Western blot and flow cytometric analyses revealed that the fusion proteins (cA-AmyA) of the cA domain and alpha-amylase from Streptococcus bovis 148 (AmyA) are efficiently expressed and successfully displayed on the surfaces of L. lactis cells. AmyA was also displayed on the cell surface while retaining its activity. Moreover, with an increase in the number of cA domains, the quantity of cA-AmyA fusion proteins displayed on the cell surface increased. When three repeats of the cA domain were used as an anchor protein, 82% of alpha-amylase activity was detected on the cells. The raw starch-degrading activity of AmyA was significantly higher when AmyA was fused to the C terminus of the cA domain than when it was fused to the N terminus. In addition, cA-AmyA fusion proteins were successfully displayed on the cell surfaces of Lactobacillus plantarum and Lactobacillus casei. PMID:18156338

  12. The Lactococcus lactis Thioredoxin System

    DEFF Research Database (Denmark)

    Efler, Petr

    D mutant vs. wt upon exposure to sodium arsenate showed down-regulation of several ATPases (DnaK and GroEL) and GTPases (Ef-G, Ef-Ts) concomitantly with up-regulation of enzymes involved in aerobiosis and nucleotide metabolism in the ΔtrxD mutant. The ΔtrxAΔtrxD deletion mutant is viable, in agreement with...

  13. Multidrug resistance in Lactococcus lactis

    NARCIS (Netherlands)

    Bolhuis, Hendrik

    1996-01-01

    Multidrug resistance (MDR) was initially recongnized as the major cause of the failure of the drug-based treatment of human cancers. It has become increasingly clear that MDR occurs in mammalian cells but also in lower eukaryotes and bacteria. The appearance of multiple antibiotic resistant micro-or

  14. Multidrug resistance in Lactococcus lactis

    OpenAIRE

    Bolhuis, Hendrik

    1996-01-01

    Multidrug resistance (MDR) was initially recongnized as the major cause of the failure of the drug-based treatment of human cancers. It has become increasingly clear that MDR occurs in mammalian cells but also in lower eukaryotes and bacteria. The appearance of multiple antibiotic resistant micro-organisms forms the major cause for the re-emergence of a number of infectious diseases that were believed to be controlled or totally exterminated. ... Zie: Summary

  15. 乳源血管紧张素转移酶抑制肽在乳酸乳球菌中的表达%Expression Milk-derived Angiotensin-I Converting Enzyme Inhibitory Peptides in Lactococcus lactis

    Institute of Scientific and Technical Information of China (English)

    曲行光; 满朝新; 姚丽燕; 赵凤; 杨士芹; 姜毓君

    2011-01-01

    Objective:To express Milk-derived angiotensin-Ⅰ converting enzyme (ACE) inhibitory peptides in Lactococcus lactis (L.lactis).Methods:The four different Bovine casein-derived peptides were chosen and designed as tandem peptides (TP) with digestive enzyme restriction site among them to ensure the potent ACE inhibitory activity of TP could be activated by pepsin and trypsin in human digestive juice.The TP gene was synthesized artificially based on its amino acid sequence and bias codon of L.lactis.Then, the TP gene was co-expressed with green fluorescent protein (GFP), which was cloned in expression vector pSEC-E7 resulting in the pSEC-TP:GFP plasmid.This recombinant plasmid was transformed into L.lactis strain NZ9000 carrying regulatory genes nisR and nisK to obtain the strain NZ9000 (pSEC-TP:GFP) by electroporation.The expression of TP:GFP gene induced by Nisin was identified by RT-PCR, SDS-PAGE and Confocal scanning laser micrographs.Results: RT-PCR showed that the TP: GFP was expressed at the RNA level.SDS-PAGE analysis showed target proteins product of 35 ku.Conclusion:The expression of Milk-derived ACE inhibitory peptide has been detected in Lactococcus lactis.%在乳酸乳球菌中表达乳源血管紧张素转移酶抑制肽.选取了4种不同的来源于牛酪蛋白的血管紧张素转移酶(ACE)抑制肤,为了确保能够在人体消化液作用下正常发挥它们的ACE抑制活性,4种短肽以串联多肽(TP)的形式进行表达,并在各短肽单体间引入了人体内主要消化酶的酶切位点.根据TP的氨基酸序列和乳酸乳球菌的偏爱密码子,人工合成TP基因.然后将TP基因和绿色荧光蛋白(GFP)基因串联于载体pSEC-E7,从而构楚了pSEC-TP:GFP质粒,实现了2种蛋白在乳酸乳球菌中的共表达.经电击转化,将该重组质粒转入乳酸乳球菌NZ9000中,获得重组菌株NZ9000(pSEC-TP:CFP).用Nisin诱导TP:GFP蛋白表达.RT-PCR、激光共聚焦扫描显微镜和SDS-PAGE鉴定表达产物.RT-PCR

  16. EFSA NDA Panel (EFSA Panel on Dietetic Products, Nutrition and Allergies), 2014. Scientific Opinion on the substantiation of a health claim related to a combination of Bifidobacterium longum LA 101, Lactobacillus helveticus LA 102, Lactococcus lactis LA 103 and Streptococcus thermophilus LA 104 and

    DEFF Research Database (Denmark)

    Tetens, Inge

    to a combination of Bifidobacterium longum LA 101, Lactobacillus helveticus LA 102, Lactococcus lactis LA 103 and Streptococcus thermophilus LA 104 and reducing intestinal discomfort. The food that is the subject of the health claim is a combination of four bacterial strains—B. longum LA 101, L....... helveticus LA 102, L. lactis LA 103 and S. thermophilus LA 104. The Panel considers that the food, a combination of B. longum LA 101, L. helveticus LA 102, L. lactis LA 103 and S. thermophilus LA 104, which is the subject of the health claim is sufficiently characterised. The claimed effect proposed by the...... applicant is "improves intestinal comfort". The Panel considers that reduction of gastro-intestinal discomfort is a beneficial physiological effect. The Panel considers that the only human study provided for the substantiation of the claim (with limitations) did not find an effect of a combination of the...

  17. Evaluación de la transferencia de oxígeno en cultivos con lactococcus lactis empleando un sistema de fermentación con aireación externa

    Directory of Open Access Journals (Sweden)

    Andrea Soler

    2010-10-01

    Full Text Available Título en inglés: Evaluating oxygen transfer in a Lactococcus lactis cultures using an external aeration fermentation system (EAFS Resumen En fermentaciones aerobias el oxígeno, como aceptor terminal de electrones en el proceso de respiración, comúnmente se constituye en limitante debido entre otros factores al diseño del biorreactor (factores geométricos, a las condiciones de operación de los fermentadores (condiciones ambientales requeridas en el cultivo, potencia transferida al cultivo por el sistema de agitación, propiedades del medio líquido, demanda de oxígeno por parte del microorganismo, sistema de aireación (concentración de oxígeno en el gas, solubilidad del oxígeno. La limitación de oxígeno se refleja en la fermentación con Lactococcus lactis cepa IBUN 34.1, en que presenta una baja disponibilidad de oxígeno desde muy temprano en la fase exponencial del cultivo. Para superar estas limitaciones se diseñó y desarrolló un sistema de suministro de oxígeno de alta tasa de transferencia, consistente en un sistema de fermentación con aireación externa (SFAE, el cual es comparado en este trabajo con el sistema tradicional de fermentador agitado dotado con dos turbinas tipo Rushton y aireación por difusor interno. En este trabajo se evalúa la operación del SFAE, se seleccionan y estudian algunas variables operacionales y su efecto sobre la transferencia de oxígeno gas-líquido. Los resultados indican que las variables que tienen efecto significativo sobre el coeficiente volumétrico global de transferencia de masa kLa son la agitación y el flujo de medio de cultivo que circula por el aireador externo denominado flujo de recirculación. Los valores de kLa obtenidos indican que con el fermentador convencional con aireación interna el mayor valor de kLa alcanzado fue de 40,68 (h-1, en tanto que con el SFAE se alcanzaron valores de 63,18 (h-1. Palabras clave: biorreactores; kLa; transferencia de ox

  18. The level of pyruvate-formate lyase controls the shift from homolactic to mixed-acid product formation in Lactococcus lactis

    DEFF Research Database (Denmark)

    Melchiorsen, C.R.; Jokumsen, K.V.; Villadsen, John;

    2002-01-01

    promoters in L. lactis MG1363 and in the PFL-deficient strain CRM40. Strains with five different PFL levels were obtained. Variation in the PFL level markedly affected the resulting end-product formation in these strains. During growth on galactose, the flux towards mixed-acid products was to a great extent...

  19. Scientific Opinion on the substantiation of a health claim related to a combination of Bifidobacterium longum LA 101, Lactobacillus helveticus LA 102, Lactococcus lactis LA 103 and Streptococcus thermophilus LA 104 and improves stool frequency pursuant to Article 13(5 of Regulation (EC No 1924/2006

    Directory of Open Access Journals (Sweden)

    EFSA Panel on Dietetic Products, Nutrition and Allergies (NDA

    2013-02-01

    Full Text Available Following an application from PiLeJe submitted for authorisation of a health claim pursuant to Article 13(5 of Regulation (EC No 1924/2006 via the Competent Authority of France, the Panel on Dietetic Products, Nutrition and Allergies (NDA was asked to deliver an opinion on the scientific substantiation of a health claim related to a combination of Bifidobacterium longum LA 101, Lactobacillus helveticus LA 102, Lactococcus lactis LA 103 and Streptococcus thermophilus LA 104 and improves stools frequency. The food that is the subject of the health claim is a combination of B. longum LA 101, L. helveticus LA 102, L. lactis LA 103 and S. thermophilus LA 104. The information provided was insufficient to establish that the strain L. lactis LA 103 was sufficiently characterised. The Panel considers that if in a combination of several microorganisms and/or ingredients one microorganism or ingredient used in the combination is not sufficiently characterised, then the combination is considered to be not sufficiently characterised. A combination of B. longum LA 101, L. helveticus LA 102, L. lactis LA 103, and S. thermophilus LA 104 is not sufficiently characterised. The Panel concludes that a cause and effect relationship cannot be established between the consumption of a combination of B. longum LA 101, L. helveticus LA 102, L. lactis LA 103 and S. thermophilus LA 104 and improves stool frequency.

  20. Induction of heat shock proteins DnaK, GroEL, and GroES by salt stress in Lactococcus lactis

    DEFF Research Database (Denmark)

    Kilstrup, Mogens; Jacobsen, Susanne; Hammer, Karin;

    1997-01-01

    , by comparison of prototrophic wild-type strains and auxotrophic domesticated (daily) strains. In a study of the capacity of domesticated strains to perform directed responses toward various stress conditions, we have analyzed the heat and salt stress response in the established L,. lactis subsp. cremoris...... laboratory strain MG1363, which was originally derived from a dairy strain, After two-dimensional separation of proteins, the DnaK, GroEL, and GroES heat shock proteins, the HrcA (Orf1) heat shack repressor, and the glycolytic enzymes pyruvate kinase, glyceral-dehyde-3-phosphate dehydrogenase......, and phosphoglycerate kinase were identified by a combination of Western blotting and direct N-terminal amino acid sequencing of proteins from the gels, Of 400 to 500 visible proteins, 17 were induced more than twofold during heat stress, Two classes of heat stress proteins were identified from their temporal induction...

  1. Bacterium-like Particles for efficient immune stimulation of existing vaccines and new subunit vaccines in mucosal applications

    Directory of Open Access Journals (Sweden)

    Natalija eVan Braeckel-Budimir

    2013-09-01

    Full Text Available The successful development of a mucosal vaccine critically depends on the use of a safe and effective immunostimulant and/or carrier system. This review describes the effectiveness and mode of action of an immunostimulating particle derived from bacteria in mucosal subunit vaccines. The non-living particles, designated Bacterium-like Particles (BLPs are based on the food-grade bacterium Lactococcus lactis. The focus of the overview is on the development of intranasal BLP-based vaccines to prevent diseases caused by influenza and respiratory syncytial virus, and includes a selection of Phase I clinical data for the intranasal FluGEM vaccine.

  2. Bacterium-Like Particles for Efficient Immune Stimulation of Existing Vaccines and New Subunit Vaccines in Mucosal Applications

    Science.gov (United States)

    Van Braeckel-Budimir, Natalija; Haijema, Bert Jan; Leenhouts, Kees

    2013-01-01

    The successful development of a mucosal vaccine depends critically on the use of a safe and effective immunostimulant and/or carrier system. This review describes the effectiveness and mode of action of an immunostimulating particle, derived from bacteria, used in mucosal subunit vaccines. The non-living particles, designated bacterium-like particles are based on the food-grade bacterium Lactococcus lactis. The focus of the overview is on the development of intranasal BLP-based vaccines to prevent diseases caused by influenza and respiratory syncytial virus, and includes a selection of Phase I clinical data for the intranasal FluGEM vaccine. PMID:24062748

  3. Human Gut-Commensalic Lactobacillus ruminis ATCC 25644 Displays Sortase-Assembled Surface Piliation: Phenotypic Characterization of Its Fimbrial Operon through In Silico Predictive Analysis and Recombinant Expression in Lactococcus lactis.

    Directory of Open Access Journals (Sweden)

    Xia Yu

    Full Text Available Sortase-dependent surface pili (or fimbriae in Gram-positive bacteria are well documented as a key virulence factor for certain harmful opportunistic pathogens. However, it is only recently known that these multi-subunit protein appendages are also belonging to the "friendly" commensals and now, with this new perspective, they have come to be categorized as a niche-adaptation factor as well. In this regard, it was shown earlier that sortase-assembled piliation is a native fixture of two human intestinal commensalics (i.e., Lactobacillus rhamnosus and Bifidobacterium bifidum, and correspondingly where the pili involved have a significant role in cellular adhesion and immunomodulation processes. We now reveal that intestinal indigenous (or autochthonous Lactobacillus ruminis is another surface-piliated commensal lactobacillar species. Heeding to in silico expectations, the predicted loci for the LrpCBA-called pili are organized tandemly in the L. ruminis genome as a canonical fimbrial operon, which then encodes for three pilin-proteins and a single C-type sortase enzyme. Through electron microscopic means, we showed that these pilus formations are a surface assemblage of tip, basal, and backbone pilin subunits (respectively named LrpC, LrpB, and LrpA in L. ruminis, and also when expressed recombinantly in Lactococcus lactis. As well, by using the recombinant-piliated lactococci, we could define certain ecologically relevant phenotypic traits, such as the ability to adhere to extracellular matrix proteins and gut epithelial cells, but also to effectuate an induced dampening on Toll-like receptor 2 signaling and interleukin-8 responsiveness in immune-related cells. Within the context of the intestinal microcosm, by wielding such niche-advantageous cell-surface properties the LrpCBA pilus would undoubtedly have a requisite functional role in the colonization dynamics of L. ruminis indigeneity. Our study provides only the second description of a

  4. Scientific Opinion on the substantiation of a health claim related to a combination of Bifidobacterium longum LA 101, Lactobacillus helveticus LA 102, Lactococcus lactis LA 103 and Streptococcus thermophilus LA 104 and reducing intestinal discomfort pursuant to Article 13(5 of Regulation (EC No 1924/2006

    Directory of Open Access Journals (Sweden)

    EFSA Panel on Dietetic Products, Nutrition and Allergies (NDA

    2014-05-01

    Full Text Available Following an application from PiLeJe, submitted pursuant to Article 13(5 of Regulation (EC No 1924/2006 via the Competent Authority of France, the Panel on Dietetic Products, Nutrition and Allergies (NDA was asked to deliver an opinion on the scientific substantiation of a health claim related to a combination of Bifidobacterium longum LA 101, Lactobacillus helveticus LA 102, Lactococcus lactis LA 103 and Streptococcus thermophilus LA 104 and reducing intestinal discomfort. The food that is the subject of the health claim is a combination of four bacterial strains—B. longum LA 101, L. helveticus LA 102, L. lactis LA 103 and S. thermophilus LA 104. The Panel considers that the food, a combination of B. longum LA 101, L. helveticus LA 102, L. lactis LA 103 and S. thermophilus LA 104, which is the subject of the health claim is sufficiently characterised. The claimed effect proposed by the applicant is "improves intestinal comfort". The Panel considers that reduction of gastro-intestinal discomfort is a beneficial physiological effect. The Panel considers that the only human study provided for the substantiation of the claim (with limitations did not find an effect of a combination of the bacterial strains being the subject of the claim on gastrointestinal discomfort. The Panel concludes that a cause and effect relationship has not been established between the consumption of a combination of B. longum LA 101, L. helveticus LA 102, L. lactis LA 103 and S. thermophilus LA 104 and reducing gastro-intestinal discomfort.

  5. EFSA NDA Panel (EFSA Panel on Dietetic Products, Nutrition and Allergies), 2014. Scientific Opinion on the substantiation of a health claim related to a combination of Bifidobacterium longum LA 101, Lactobacillus helveticus LA 102, Lactococcus lactis LA 103 and Streptococcus thermophilus LA 104 and

    DEFF Research Database (Denmark)

    Tetens, Inge

    to a combination of Bifidobacterium longum LA 101, Lactobacillus helveticus LA 102, Lactococcus lactis LA 103 and Streptococcus thermophilus LA 104 and improvement of bowel function by increasing stool frequency. The food that is the subject of the health claim is a combination of four bacterial...... effect proposed by the applicant is "improves stool frequency". The Panel considers that improvement of bowel function by increasing stool frequency, provided that it does not result in diarrhoea, is a beneficial physiological effect. The Panel considers that the human study provided for the...... substantiation of the claim did not find an increase in stool frequency following consumption of a combination of the bacterial strains which is the subject of the claim. The Panel concludes that a cause and effect relationship has not been established between the consumption of a combination of B. longum LA 101...

  6. A comparative study between inhibitory effect of L. lactis and nisin on important pathogenic bacteria in Iranian UF Feta cheese

    OpenAIRE

    Saeed Mirdamadi; Shadi Agha Ghazvini

    2015-01-01

      Introduction : In the present study, the inhibitory effect of nisin-producing Lactococcus lactis during co-culture and pure standard nisin were assessed against selected foodborne pathogenes in growth medium and Iranian UF Feta cheese. In comparison L lactis, not only proves flavor but also plays a better role in microbial quality of Iranian UF Feta cheese as a model of fermented dairy products.   Materials and method s: L. lactis subsp. lactis as nisin producer strain, Listeria monocytogen...

  7. Physiology of exopolysaccharide biosynthesis by Lactococcus lactis

    NARCIS (Netherlands)

    Looijesteijn, P.J.

    2000-01-01

    Several lactic acid bacteria (LAB) produce exopolysaccharides (EPS). EPSs produced by LAB are a potential source of natural additives and because LAB are food grade organisms, these EPSs can also be produced in situ . The amount of EPS in milk fermented with strain NIZO B40, which produces an anioni

  8. Physiology of exopolysaccharide biosynthesis by Lactococcus lactis

    OpenAIRE

    Looijesteijn, P.J.

    2000-01-01

    Several lactic acid bacteria (LAB) produce exopolysaccharides (EPS). EPSs produced by LAB are a potential source of natural additives and because LAB are food grade organisms, these EPSs can also be produced in situ . The amount of EPS in milk fermented with strain NIZO B40, which produces an anionic EPS composed of glucose, rhamnose, galactose and phosphate, is very low. This relatively low concentration could be increased by optimising the culture conditions and medium composition. Using pH...

  9. Construction of the recombinant Lactococcus lactis expressing HIV-1 gag protein and its colonization in mice%表达HIV-1 gag蛋白重组乳酸乳球菌株的建立及其在小鼠体内定植的研究

    Institute of Scientific and Technical Information of China (English)

    张彩荣; 吴玲玲; 侯向前; 马正海

    2013-01-01

    目的 构建表达HIV-1 gag的重组乳酸乳球菌,并分析重组菌在小鼠体内的定植情况.方法 将HIV-1 gag克隆至原核表达质粒pMG36e,重组质粒pMG36e-gag电转乳酸乳球菌,SDS-PAGE和Western blot法检测其在乳酸乳球菌中的表达.以109个重组菌给小鼠口服,对照组口服PBS.口服后第1、3、5、7、9、11天分别取小鼠的胃、小肠和大肠,采用稀释滴种法测定小鼠胃、肠道内重组菌的数量.结果 酶切和DNA测序表明gag已克隆入pMG36e.SDS-PAGE在预期位置检测到蛋白条带,Western blot分析证实其为gag蛋白.重组菌定植实验表明,第1、3天在胃肠均有一定量重组菌,且大肠中重组菌数量多于胃和小肠,随后胃肠中重组菌均迅速减少,仅在大肠中仍有一定量的重组菌,第11天时胃肠仅分离到极少量的重组菌.结论 本研究获得胞内表达HIV-1 gag前体蛋白Pr55的重组乳酸乳球菌,其可在胃肠中短期存活,可作为预防HIV-1感染的候选疫苗.%Objective To construct the recombinant Lactococcus lactis(L.lactis) expressing HIV-1 gag and research its colonization in mice.Methods HIV-1 gag was cloned into prokaryotic expression plasmid pMG36e,then the recombinant plasmid (pMG36e-gag) was electrotransformed into L.lactis.The expression of gag in L.lactis was analyzed by SDS-PAGE and Western blotting,respectively.The experimental mice were administrated orally with the 1 × 109 L.lactis,and the control mice with PBS instead.At 1,3,5,7,9 and 11 d after administration,the mice were sacrificed,and then the stomach,small intestine and large intestine were taken from each mouse.The L.lactis number of colonization in these tissues were assayed by means of diluting and dripping.Results Restriction endonuclease analysis and DNA sequencing confirmed that gag had been cloned into the plasmid pMG36e.SDS-PAGE and Western blotting identified the gag antigen in L.lactis as we expected.At 1 and 3 d,there were some colonized

  10. Expression of the Phage Lysin LySMP in Lactococcus lactis and Studies on its Antibiotic Bioactivities%猪链球菌噬菌体SMP裂解酶在乳酸乳球菌中的表达及活性研究

    Institute of Scientific and Technical Information of China (English)

    方圆子; 王琰; 孙建和

    2011-01-01

    Streptococcus suis phage (SMP) shows narrow spectrum in its host range, which limited its potential application in clinic. Previous studies indicated that the bacteriophage lysine synthesized by LySMP could effectively broaden its lytic spectrum. In this study, the LySMP gene was obtained from the PCR amplification using SMP gene as the template and then was inserted into an expression plasmid of pNZ8148. The recombinant plasmid pNZ8148-LySMP was established by the electro-transformation of the pNZ8148 into Lactococcus lactis NZ9000 and the expression of LySMP was induced by Nisin. The degraded bacterial turbidity test showed that 7 strains of Streptococcus suis-2 and Streptococcus suis-9 possessed high sensitivity to SMP lysine and the turbidity could be decreased by 30% ~ 77% in 30 min. It was concluded that SMP lysin has been successfully expressed in Lactococcus lactis using NICE expression system,providing the potential application of the LySMP in clinic.%猪链球菌(Streptococcus suis,SS)烈性噬菌体SMP的宿主谱窄,制约了其临床应用潜力.研究发现,由噬菌体编码的裂解酶(LySMP)可有效拓宽其裂解谱.本研究以SMP基因组DNA为模板,扩增获得SMP裂解酶基因,将其克隆至质粒pNZ8148中,电转化乳酸乳球菌NZ9000,获得重组乳酸乳球菌NZ9000(pNZ8148-LySMP),经Nisin诱导可表达LySMP.浊度递减实验结果显示,所表达的LySMP对7株猪链球菌2型菌株和猪链球菌9型菌株有较高的裂解活性,浊度下降可达30%~77%.表明利用NICE表达系统及pNZ8148表达载体在乳酸乳球菌中可实现猪链球菌噬菌体裂解酶的活性表达,为开展LySMP的应用研究提供了可能.

  11. ВЛИЯНИЕ УГЛЕВОДОВ НА ПРОТЕОЛИТИЧЕСКУЮ АКТИВНОСТЬ ШТАММОВ LACTOCOCCUS LACTIS

    OpenAIRE

    Брацихина, Мария; Рябцева, Светлана

    2012-01-01

    Исследовано влияние пребиотика лактулозы, лактозы и глюкозы на протеолитическую активность двух генетически модифицированных штаммов Lactococcus lactis pNZ45subC и pNZ48CE. Установлено, что наивысшая про-теолитическая активность обоих штаммов наблюдается в присутствии глюкозы. Внесение лактозы и лактулозы, вероятно, блокирует действие низина, индуцирующего синтез протеазы штаммами L. lactis pNZ45subC и pNZ48CE, в связи с чем отмечено значительное снижение протеолитической активности. Полученн...

  12. Selective enumeration and viability of Bifidobacterium animalis subsp. lactis in a new fermented milk product Enumeração seletiva e viabilidade de Bifidobacterium animalis subsp. lactis em um novo produto lácteo fermentado

    Directory of Open Access Journals (Sweden)

    Adriane Elisabete Costa Antunes

    2007-03-01

    Full Text Available One of the key focuses of today's dairy industry worldwide is the continued development of new products, especially probiotic-based products. Buttermilk is originally a by-product of butter making fermented by Mesophilic Aromatic Cultures (MAC. It can also be made by fermentation of pasteurized whole milk or skimmed milk. This product is not marketed in Brazil. The objectives of this work were: (1 to develop a selective medium for Bifidobacterium animalis subsp. lactis enumeration and (2 to determine the viability of this microorganism during the shelf life of the buttermilk. Skim milk added with 10% sucrose or 0.03% sucralose was pasteurized and inoculated with a composite starter culture consisting of 1% MAC (containing Lactococcus lactis subsp. cremoris, Lactococcus lactis subsp. lactis, Lactococcus lactis subsp. lactis biovar. diacetylactis and Leuconostoc mesenteroides subsp. cremoris and 2% Bifidobacterium animalis subsp. lactis. To attain selective counts of Bif. animalis subsp. lactis the MRS agar supplemented with 0.5% L-cysteine hydrochloride at 10%, 1% lithium chloride at 10%, 0.01% aniline blue and 0.5% dicloxacillin at 0.1% was modified by increasing the antibiotic concentration, addition of NaCl, adjusting pH to 4.8 or increasing the incubation temperature (from 37 to 45ºC. Raising the incubation temperature to 45ºC was found to be efficient in inhibiting the MAC cultures, even in media not added with dicloxacillin. Bif. animalis subsp. lactis exhibited high viability in the product. The buttermilk product prepared with sucrose and sweetener contained in excess of 10(8 cfu.ml-1 bifidobacteria throughout the shelf life of the product (28 days.Atualmente, um dos principais focos da indústria de laticínios em todo o mundo é o desenvolvimento de novos produtos, especialmente probióticos. Buttermilk é originalmente um sub-produto do processamento da manteiga fermentado por Culturas Aromáticas Mesofílicas (MAC. Pode também ser

  13. Activities of amylase, proteinase, and lipase enzymes from Lactococcus chungangensis and its application in dairy products.

    Science.gov (United States)

    Konkit, Maytiya; Kim, Wonyong

    2016-07-01

    Several enzymes are involved in the process of converting milk to lactic acid and coagulated milk to curd and, therefore, are important in dairy fermented products. Amylase, proteinase, and lipase are enzymes that play an important role in degrading milk into monomeric molecules such as oligosaccharides, amino acids, and fatty acids, which are the main molecules responsible for flavors in cheese. In the current study, we determined the amylase, proteinase, and lipase activities of Lactococcus chungangensis CAU 28(T), a bacterial strain of nondairy origin, and compared them with those of the reference strain, Lactococcus lactis ssp. lactis KCTC 3769(T), which is commonly used in the dairy industry. Lactococcus chungangensis CAU 28(T) and L. lactis ssp. lactis KCTC 3769(T) were both found to have amylase, proteinase, and lipase activities in broth culture, cream cheese, and yogurt. Notably, the proteinase and lipase activities of L. chungangensis CAU 28(T) were higher than those of L. lactis ssp. lactis KCTC 3769(T), with proteinase activity of 10.50 U/mL in tryptic soy broth and 8.64 U/mL in cream cheese, and lipase activity of 100 U/mL of tryptic soy broth, and 100 U/mL of cream cheese. In contrast, the amylase activity was low, with 5.28 U/mL in tryptic soy broth and 8.86 U/mL in cream cheese. These enzyme activities in L. chungangensis CAU 28(T) suggest that this strain has potential to be used for manufacturing dairy fermented products, even though the strain is of nondairy origin. PMID:27108177

  14. Metabolic shifts in microorganisms: the case of Lactococcus lactis

    OpenAIRE

    Goel, A.

    2013-01-01

      A commonly observed organismal response to changing growth rate is a metabolic shift from one mode of metabolism to another. This phenomenon is potentially interesting from a fundamental and industrial perspective because it can influence cellular choices and can limit the capacity of industrial microorganisms to channel nutrients to desired products. The mechanistic cause of the metabolic shift may vary between species, but the presence of such shifts from bacteria to man suggests fun...

  15. Structural characterisation and enzymic modification of exopolysaccharides from Lactococcus lactis

    OpenAIRE

    Casteren, van, DTEH Dave

    2000-01-01

    Since ancient times, lactic acid bacteria have been used for the preservation of food. Some of these bacteria are able to produce exopolysaccharides (EPSs), which may contribute to the peculiar rheology and texture of, for example, milk-derived products. Insight into the relationship between the chemical structure of EPSs and their physical properties can lead to tailor-made polysaccharides, which meet particular requirements in terms of structure and function. In this thesis, the elucidation...

  16. Functional Expression of an Orchid Fragrance Gene in Lactococcus lactis

    OpenAIRE

    Adelene Ai Lian Song; Abdullah, Janna O.; Mohd Puad Abdullah; Norazizah Shafee; Rahim, Raha A

    2012-01-01

    Vanda Mimi Palmer (VMP), an orchid hybrid of Vanda tesselata and Vanda Tan Chay Yan is a highly scented tropical orchid which blooms all year round. Previous studies revealed that VMP produces a variety of isoprenoid volatiles during daylight. Isoprenoids are well known to contribute significantly to the scent of most fragrant plants. They are a large group of secondary metabolites which may possess valuable characteristics such as flavor, fragrance and toxicity and are produced via two pathw...

  17. Proteome analysis of the purine stimulon from Lactococcus lactis

    DEFF Research Database (Denmark)

    Beyer, N.H.; Roepstorff, P.; Hammer, Karin;

    2003-01-01

    members are down-regulated during purine depletion, contained proteins related to protein synthesis (PpsB, EF-TS, trigger factor), or to GTPases (FtsZ, EF-TS); or are involved in energy metabolism (GapB, CcpA). No common regulatory elements could be found for members of this stimulon. Two Psd proteins...

  18. Transforming Lactococcus lactis into a microbial cell factory

    DEFF Research Database (Denmark)

    Petersen, Kia Vest

    of undesirable elements relies on a modified Cre-loxP system and 5-fluoroorotate mediated counter-selection. The plasmid used for the site-specific integration was termed pKV6 and when it is used for integrating genes, a new attachment site, attBmin, is likewise introduced, which can subsequently be used...

  19. Metabolic Engineering of Exopolysaccharide Production in Lactococcus lactis

    NARCIS (Netherlands)

    Boels, I.C.

    2002-01-01

    Exopolysaccharides (EPS) produced by lactic acid bacteria are important structural components in fermented foods. In addition, they may confer health benefits to the consumer, as mouse model studies have indicated that EPS may have immunostimulatory, anti-tumoral,

  20. Exopolysaccharide biosynthesis in Lactococcus lactis : a molecular characterisation

    NARCIS (Netherlands)

    Kranenburg, van R.

    1999-01-01

    Lactic acid bacteria are Gram-positive bacteria which are used for industrial food fermentation processes. Some have the ability to form exopolysaccharides (EPSs) and these bacteria or the produced EPSs can be used to enhance the structural properties of food products. Furthermore, these EPSs are cl

  1. Resistance to antibiotics in Lacid acid bacteria - strain Lactococcus

    Directory of Open Access Journals (Sweden)

    Filipić Brankica

    2015-01-01

    Full Text Available Lactic acid bacteria (LAB are widely used in the food industry, especially in the production of fermented dairy products and meat. The most studied species among Lis Lactococcus lactis. L. lactis strains are of great importance in the production of fermented dairy products such as yogurt, butter, fresh cheese and some kind of semi-hard cheese. Although L. lactis acquired the „Generally Regarded As Safe“ (GRAS status, many investigations indicated that lactococci may act as reservoirs of antibiotic resistance genes, which could be transferred to other bacterial species in human gastrointestinal tract includ­ing pathogens. The genome analysis of L. lactis indicated the presence of at least 40 putative drug transporter genes, and only four multidrug resistance (MDR transporters are functionally characterized: LmrA, LmrP, LmrCD i CmbT. LmrA is the first described MDR transporter in prokaryotes. LmrCD is responsible for resistance to cholate, which is an integral part of human bile and LmrCD is important for intestinal survival of lactococci that are used as probiotics. Secondary multidrug transporter LmrP confers resistance to lincosamides, macrolides, streptogramins and tetracyclines. CmbT protein has an effect on the host cell resistance to lincomycin, sulfadiazine, streptomycin, rifampicin, puromycin and sulfametox­azole. Since the food chain is an important way of transmitting resistance genes in human and animal population, it is of great importance to study the mechanisms of resistance in lactococci and other LAB, intended for the food industry. [Projekat Ministarstva nauke Republike Srbije, br. 173019: Izučavanje gena i molekularnih mehanizama u osnovi probiotičke aktivnosti bakterija mlečne kiseline izolovanih sa područja Zapadnog Balkana

  2. A comparative study between inhibitory effect of L. lactis and nisin on important pathogenic bacteria in Iranian UF Feta cheese

    Directory of Open Access Journals (Sweden)

    Saeed Mirdamadi

    2015-02-01

    Full Text Available   Introduction : In the present study, the inhibitory effect of nisin-producing Lactococcus lactis during co-culture and pure standard nisin were assessed against selected foodborne pathogenes in growth medium and Iranian UF Feta cheese. In comparison L lactis, not only proves flavor but also plays a better role in microbial quality of Iranian UF Feta cheese as a model of fermented dairy products.   Materials and method s: L. lactis subsp. lactis as nisin producer strain, Listeria monocytogenes, Escherichia coli and Staphylococcus aureus as pathogenic strains were inoculated in Ultra-Filtered Feta cheese. Growth curve of bacterial strains were studied by colony count method in growth medium and UF Feta cheese separately and during co-culture with L. lactis. Nisin production was determined by agar diffusion assay method against susceptible test strain and confirmed by RP-HPLC analysis method.   Results : Counts of L. monocytogenes decreased in cheese sample containing L. lactis and standard nisin, to 103 CFU/g after 7 days and it reached to undetectable level within 2 weeks. S. aureus counts remained at its initial number, 105 CFU/g, after 7 days then decreased to 104 CFU/g on day 14 and it was not detectable on day 28. E. coli numbers increased in both treatments after 7 days and then decreased to 104 CFU/g after 28 days. Despite the increasing number of E. coli in growth medium containing nisin, due to the synergistic effect of nisin and other metabolites produced by Lactococcus lactis and starter cultures, the number of E. coli decreased with slow rate . Discussion and conclusion : The results showed, L. monocytogenes was inhibited by L. lactis before entering the logarithmic phase during co-culture. S. aureus was also inhibited during co-culture, but it showed less sensitivity in comparison with L. monocytogenes. However, the number of E. coli remained steady in co-culture with L. lactis. Also, we found that, in all cheese samples, E

  3. Heterologous production of human papillomavirus type-16 L1 protein by a lactic acid bacterium

    Directory of Open Access Journals (Sweden)

    Bermúdez-Humarán Luis G

    2009-08-01

    Full Text Available Abstract Background The expression of vaccine antigens in lactic acid bacteria (LAB is a safe and cost-effective alternative to traditional expression systems. In this study, we investigated i the expression of Human papillomavirus type 16 (HPV-16 L1 major capsid protein in the model LAB Lactococcus lactis and ii the ability of the resulting recombinant strain to produce either capsomer-or virus-like particles (VLPs. Results and conclusion HPV-16 L1 gene was cloned into two vectors, pCYT and pSEC, designed for controlled intra- or extracellular heterologous expression in L. lactis, respectively. The capacity of L. lactis harboring either pCYT:L1 or pSEC:L1 plasmid to accumulate L1 in the cytoplasm and supernatant samples was confirmed by Western blot assays. Electron microscopy analysis suggests that, L1 protein produced by recombinant lactococci can self-assemble into structures morphologically similar to VLPs intracellularly. The presence of conformational epitopes on the L. lactis-derived VLPs was confirmed by ELISA using an anti-HPV16 L1 capsid antigen antibody. Our results support the feasibility of using recombinant food-grade LAB, such as L. lactis, for the production of L1-based VLPs and open the possibility for the development of a new safe mucosal vector for HPV-16 prophylactic vaccination.

  4. Enhancing bile tolerance improves survival and persistence of Bifidobacterium and Lactococcus in the murine gastrointestinal tract

    Directory of Open Access Journals (Sweden)

    Hill Colin

    2008-10-01

    Full Text Available Abstract Background The majority of commensal gastrointestinal bacteria used as probiotics are highly adapted to the specialised environment of the large bowel. However, unlike pathogenic bacteria; they are often inadequately equipped to endure the physicochemical stresses of gastrointestinal (GI delivery in the host. Herein we outline a patho-biotechnology strategy to improve gastric delivery and host adaptation of a probiotic strain Bifidobacterium breve UCC2003 and the generally regarded as safe (GRAS organism Lactococcus lactis NZ9000. Results In vitro bile tolerance of both strains was significantly enhanced (P Listeria monocytogenes bile resistance mechanism BilE. Strains harbouring bilE were also recovered at significantly higher levels (P n = 5, following oral inoculation. Furthermore, a B. breve strain expressing bilE demonstrated increased efficacy relative to the wild-type strain in reducing oral L. monocytogenes infection in mice. Conclusion Collectively the data indicates that bile tolerance can be enhanced in Bifidobacterium and Lactococcus species through rational genetic manipulation and that this can significantly improve delivery to and colonisation of the GI tract.

  5. Increased biomass yield of Lactococcus lactis during energetically limited growth and respiratory conditions

    DEFF Research Database (Denmark)

    Købmann, Brian Jensen; Blank, Lars Mathias; Solem, Christian; Petranovic, Dina; Nielsen, Lars K.; Jensen, Peter Ruhdal

    2008-01-01

    /mol of glucose. With maltose as the energy source, the increase in biomass yield amounted to 51% compared with an aerobic culture that lacked haemin. This higher ATP yield was obtained by redirecting pyruvate metabolism from lactate to acetate production, and from savings through respiration. However...... energy saved on proton pumping through the H+-ATPase due to respiration and partly from a reversed function of the H+-ATPase towards oxidative phosphorylation. These results may contribute to the design and implementation of carbon-efficient high-cell-density cultures of this industrially important...... MG1363 resulted in only a minor increase, 21%, in biomass yield. Since ATP production through substrate-level phosphorylation was essentially identical with and without respiration, the increased biomass yield was a result of energy-saving under respiratory conditions estimated to be 0.4 mol of ATP...

  6. Activation Control of purDEK and purC Gene Expression in Lactococcus lactis

    DEFF Research Database (Denmark)

    Kilstrup, Mogens; Jessing, Stine; Wichmand-Jørghensen, S. B;

    1998-01-01

    sequences resembling -35 regions for 70 promoters . Fusion studies point to the importance of the conserved sequences in purine mediated regulation. Adjacent to the conserved sequence in purC is a second and similar region required for high expression of the gene. A consensus “PurBox” sequence...

  7. Mecanismos implicados en la resistencia de Lactococcus lactis a la bacteriocina Lcn972

    OpenAIRE

    Roces, Clara; Campelo, Ana B; Pérez, Verónica; BLANCO, DIEGO; Rodríguez González, Ana; Martínez Fernández, Beatriz

    2012-01-01

    Comunicación presentada en la 6ª reunión de la Red temática BAL (Participación de las Bacterias Lácticas en la Salud Humana y en la Calidad Alimentaria), celebrada el 28 y 29 de junio de 2012 en Tarragona.

  8. Coculture-inducible bacteriocin biosynthesis of different probiotic strains by dairy starter culture Lactococcus lactis

    OpenAIRE

    Blaženka Kos; Jasna Beganović; Lina Jurašić; Martina Švađumović; Andreja Leboš Pavunc; Ksenija Uroić; Jagoda Šušković

    2011-01-01

    Bacteriocins produced by probiotic strains effectively contribute to colonization ability of probiotic strains and facilitate their establishment in the competitive gut environment and also protect the gut from gastrointestinal pathogens. Moreover, bacteriocins have received considerable attention due to their potential application as biopreservatives, especially in dairy industry. Hence, the objective of this research was to investigate antimicrobial activity of probiotic strains Lactobacill...

  9. Maturation of the cell envelope-associated proteinase of lactococcus lactis.

    NARCIS (Netherlands)

    Haandrikman, Alfred Jacques

    1990-01-01

    Lactococci are of major economic importance for their use in production and preservation of cheese and other fermented milk products. The succes of this use depends on the fast production of lactic acid, which goes together with fast growth of lacctococci in milk. The amount of free amino acids and

  10. SpxB regulates O-acetylation-dependent resistance of Lactococcus lactis peptidoglycan to hydrolysis

    NARCIS (Netherlands)

    Veiga, Patrick; Bulbarela-Sampieri, Carmen; Furlan, Sylviane; Maisons, Aurelie; Chapot-Chartier, Marie-Pierre; Erkelenz, Michael; Mervelet, Peggy; Noirot, Philippe; Frees, Dorte; Kuipers, Oscar P.; Kok, Jan; Gruss, Alexandra; Buist, Girbe; Kulakauskas, Saulius

    2007-01-01

    Endogenous peptidoglycan (PG)-hydrolyzing enzymes, the autolysins, are needed to relax the rigid PG sacculus to allow bacterial cell growth and separation. PGs of pathogens and commensal bacteria may also be degraded by hydrolases of animal origin (lysozymes), which act as antimicrobials. The geneti

  11. Molekulare Mechanismen der allergieprotektiven Wirkung durch Lactococcus lactis im Mausmodell des akuten allergischen Asthma

    OpenAIRE

    Niesel, Stefan Christian

    2012-01-01

    Als ursächlich für in den letzten Jahrzehnten stetig steigenden Prävalenzen von Asthma bronchiale in industrialisierten Ländern werden neben einer genetischen Prädisposition vor allem Umweltfaktoren verantwortlich gemacht. Die Hygiene-Hypothese bestätigend konnten epidemiologische Studien eine Reduktion allergischer Erkrankungen durch Exposition gegenüber mikrobiellen Komponenten im bäuerlichen Umfeld belegen. In Folge wurde das ...

  12. Bacteriophage resistance of a Delta thyA mutant of Lactococcus lactis blocked in DNA replication

    DEFF Research Database (Denmark)

    Pedersen, M.B.; Jensen, Peter Ruhdal; Janzen, T.;

    2002-01-01

    , such as milk, there was no detectable d'ITP pool in the cells. Hence, DNA replication was abolished, and acidification by MBP71 was completely unaffected by the presence of nine different phages tested at a multiplicity of infection (MOI) of 0.1. Nonreplicating MBP71 must be inoculated at a higher...

  13. Monte-Carlo Modeling of the Central Carbon Metabolism of Lactococcus lactis: Insights into Metabolic Regulation

    Czech Academy of Sciences Publication Activity Database

    Murabito, E.; Verma, M.; Bekker, M.; Bellomo, D.; Westerhoff, H. V.; Teusink, B.; Steuer, Ralf

    2014-01-01

    Roč. 9, č. 9 (2014), e106453. E-ISSN 1932-6203 R&D Projects: GA MŠk(CZ) EE2.3.20.0256 Institutional support: RVO:67179843 Keywords : systems biology * aced bacteria * Escherichia-coli * framework development * rate laws * dehydrogenase Subject RIV: EI - Biotechnology ; Bionics Impact factor: 3.234, year: 2014

  14. Milk Contamination and Resistance to Processing Conditions Determine the Fate of Lactococcus lactis Bacteriophages in Dairies

    OpenAIRE

    Madera, Carmen; Monjardín, Cristina; Suárez, Juan E.

    2004-01-01

    Milk contamination by phages, the susceptibility of the phages to pasteurization, and the high levels of resistance to phage infection of starter strains condition the evolution dynamics of phage populations in dairy environments. Approximately 10% (83 of 900) of raw milk samples contained phages of the quasi-species c2 (72%), 936 (24%), and P335 (4%). However, 936 phages were isolated from 20 of 24 (85%) whey samples, while c2 was detected in only one (4%) of these samples. This switch may h...

  15. Metabolic behavior of Lactococcus lactis MG1363 in microaerobic continuous cultivation at a low dilution rate

    DEFF Research Database (Denmark)

    Jensen, Niels B.S.; Melchiorsen, Claus Rix; Jochumsen, Kirsten Væver;

    2001-01-01

    of even minute amounts of oxygen increased the yield of biomass on glucose by more than 10% compared to that obtained under anaerobic conditions and had a dramatic impact on catabolic enzyme activities and hence on the distribution of carbon at the pyruvate branch point. Increasing aeration caused...

  16. Molecular characterization of a family of cold-shock proteins of Lactococcus lactis

    NARCIS (Netherlands)

    Wouters, J.A.

    2000-01-01

    Lactic acid bacteria (LAB) are widely used as starter cultures in fermentation processes. The stress response of LAB during different industrial processes, and during low-temperature conditions in particular, requires a better understanding. For that reason a research project on the cold adaptation

  17. Expression and release of proteolytic enzymes of Lactococcus lactis - Ripening of UF-cheese.

    NARCIS (Netherlands)

    Meijer, W.C.

    1997-01-01

    Semi-hard cheese types, such as Gouda, cannot be satisfactorily produced when using ultrafiltration technology. Although the cheese yield increases using this method, the higher financial return is completely lost by the (poor) quality of the cheese. The work described in this thesis is directed at

  18. Construction of Streptococcus lactis subsp. lactis Strains with a Single Plasmid Associated with Mucoid Phenotype

    OpenAIRE

    von Wright, Atte; Tynkkynen, Soile

    1987-01-01

    Lactose-fermenting mucoid (Lac+ Muc+) variants of plasmid-free Streptococcus lactis subsp. lactis MG1614 were obtained by protoplast transformation with total plasmid DNA from Muc+S. lactis subsp. cremoris ARH87. By using plasmid DNA from these variants for further transformations followed by novobiocininduced plasmid curing, Lac− Muc+ MG1614 strains containing only a single 30-megadalton plasmid could be constructed. This plasmid, designated pVS5, appeared to be associated with the Muc+ phen...

  19. [Finding of dairy yeasts Kluyveromyces lactis var. lactis in natural habitats].

    Science.gov (United States)

    Naumov, G I; Naumova, E S; Glushakova, A M; Kachalkin, A V; Chernov, I Y

    2014-01-01

    Well-known yeasts Kluyveromyces lactis var. lactis, which are usually associated with dairy prod- ucts, were discovered in nature (in woodland park soil under Impatiens glandulifera Royle plants). Reliable identification of the yeasts was carried out using physiological criteria (lactose and maltose utilization) and molecular markers (nucleotide sequence of the 5.8S-ITS rDNA fragment, pulsed-field electrophoresis, and Southern hybridization of chromosomal DNA with the LAC4 probe). Ecology of KI. lactis var. lactis is discussed. PMID:25941717

  20. Liposome-enhanced transformation of Streptococcus lactis and plasmid transfer by intergeneric protoplast fusion of Streptococcus lactis and Bacillus subtilis

    NARCIS (Netherlands)

    Vossen, Jos M.B.M. van der; Kok, Jan; Lelie, Daniel van der; Venema, Gerhardus

    1988-01-01

    An efficient protoplast transformation system and a procedure of plasmid transfer by means of protoplast fusion is described for Streptococcus lactis. Protoplasts of S. lactis IL1403 and S. lactis MG1363 were transformed by pGK12 [2.9 MDa erythromycin resistance (Emr)] with an efficiency of 3 × 10^5

  1. Teamwork in microbial fuels cells: symbiotic conversion of sugars into electricity

    Science.gov (United States)

    A binary culture of Lactococcus lactis and Shewanella oneidensis was studied for an efficient conversion of glucose into electricity in a continuously-operated chemostatic electrochemical reactor. The homolactic fermentation bacterium L. lactis fermented glucose almost exclusively to lactate – the ...

  2. Synergetic effects of microbial binary cultures on microbial fuel cell performance

    Science.gov (United States)

    A binary culture of Lactococcus lactis and Shewanella oneidensis was studied for an efficient conversion of glucose into electricity in a continuously-operated chemostatic electrochemical reactor. The homolactic fermentation bacterium L. lactis fermented glucose almost exclusively to lactate – the ...

  3. The extracellular proteome of Bifidobacterium animalis subsp. lactis BB‐12 reveals proteins with putative roles in probiotic effects

    DEFF Research Database (Denmark)

    Gilad, Ofir; Svensson, Birte; Viborg, Alexander Holm; Stuer‐Lauridsen, Birgitte; Jacobsen, Susanne

    2011-01-01

    Bifidobacterium animalis subsp. lactis BB‐12, proteins secreted by the bacterium, i.e. belonging to the extracellular proteome present in the culture medium, were identified by 2‐DE coupled with MALDI‐TOF MS. Among the 74 distinct proteins identified, 31 are predicted to carry out their physiological role either...... outside the cell or on its surface. These proteins include solute‐binding proteins for oligosaccharides, amino acids and manganese, cell wall‐metabolizing proteins, and 18 proteins that have been described to interact with human host epithelial cells or extracellular matrix proteins. The potential...

  4. Kluyveromyces lactis maintains Saccharomyces cerevisiae intron-encoded splicing signals.

    OpenAIRE

    Deshler, J O; Larson, G P; Rossi, J J

    1989-01-01

    The actin (ACT) gene from the budding yeast Kluyveromyces lactis was cloned, and the nucleotide sequence was determined. The gene had a single intron 778 nucleotides in length which possessed the highly conserved splicing signals found in Saccharomyces cerevisiae introns. We demonstrated splicing of heterologous ACT transcripts in both K. lactis and S. cerevisiae.

  5. The extent of co-metabolism of glucose and galactose by L. lactis changes with the expression of the lacSZ operon from Streptococcus thermophilus

    DEFF Research Database (Denmark)

    Solem, Christian; Købmann, Brian Jensen; Jensen, Peter Ruhdal

    2008-01-01

    The lactose transporter and β-galactosidase from Streptococcus thermophilus, encoded by the lacSZ operon, were introduced into the lactose-negative strain Lactococcus lactis MG1363 and the expression of the lacSZ operon was modulated by substitution of the native promoter with randomized synthetic...... only glucose was metabolized in glycolysis. Interestingly, strains with low expression of the operon showed a mixed acid metabolism and co-metabolism of galactose and glucose. The lactose flux increased gradually with increasing expression of the lacSZ operon until an optimum was observed at...... promoters. A series of strains with various expression levels of lacSZ were examined for their fermentation of lactose. Strains with a high expression level were found to metabolize lactose in a similar manner to S. thermophilus, i.e. the galactose moiety of lactose was excreted to the growth medium and...

  6. Lactococcus nasutitermitis sp. nov. isolated from a termite gut.

    Science.gov (United States)

    Yan Yang, Shu; Zheng, Ying; Huang, Zhou; Min Wang, Xue; Yang, Hong

    2016-01-01

    Bacterial strain M19T was isolated from the gut of a wood-feeding termite, Nasutitermes hainanensis. Phylogenetic analysis based on 16S rRNA gene sequences indicated that strain M19T was related to members of the genus Lactococcus, with sequence similarities ranging from 84.8 to 95.5 %. Comparison of housekeeping gene ropB sequences revealed that strain M19T was well separated from Lactococcus fujiensis JCM 16395T and Lactococcus hircilactis 117T. The isolate was Gram-stain-positive, catalase-negative and non-motile. Cells were coccoid or ovoid-shaped, and occurred singly, in pairs or as short chains. Growth of strain M19T occurred at 10-40 °C and at pH 5.0-7.5. The DNA G+C content of strain M19T was 39.6 mol% and the major fatty acids were C16 : 0, cyclo-C19 : 0ω8c, C18 : 1ω9c, summed feature 7 and summed feature 8. Based on the phylogenetic, chemotaxonomic and phenotypic data presented, strain M19T represents a novel species of the genus Lactococcus, for which the name Lactococcus nasutitermitis sp. nov. is proposed. The type strain is M19T ( = CGMCC 1.15204T = NBRC 111537T). PMID:26546382

  7. Ornithine transport and exchange in Streptococcus lactis

    International Nuclear Information System (INIS)

    Resting cells of Streptococcus lactis 133 appeared to accumulate [14C]ornithine to a high concentration in the absence of an exogenous energy source. However, analysis of intracellular amino acid pool constituents and results of transport experiments revealed that the accumulation of ornithine represented a homoexchange between extracellular [14C]ornithine and unlabeled ornithine in the cell. The energy-independent exchange of ornithine was not inhibited by proton-conducting uncouplers or by metabolic inhibitors. Intracellular [14C]ornithine was retained by resting cells after suspension in a buffered medium. However, addition of unlabeled ornithine to the suspension elicited rapid exit of labeled amino acid. The initial rate of exist of [14C]ornithine was dependent on the concentration of unlabeled ornithine in the medium, but this accelerative exchange diffusion process caused no net loss of amino acid. By contrast, the presence of a fermentable energy source caused a rapid expulsion of and new decrease in the concentration of intracellular ornithine. Kinetic analyses of amino acid transport demonstrated competitive inhibition between lysine and ornithine, and data obtained by two-dimensional thin-layer chromatography established the heteroexchange of these basic amino acids. The effects of amino acids and of ornithine analogs on both entry and exit of [14C]ornithine have been examined. The data suggest that common carrier mediates the entry and exchange of lysine, arginine, and ornithine in cells of S. lactis

  8. Molecular and Functional Analyses of the metC Gene of Lactococcus lactis, Encoding Cystathionine β-Lyase

    NARCIS (Netherlands)

    Fernández, María; Doesburg, Wim van; Rutten, Ger A.M.; Marugg, Joey D.; Alting, Arno C.; Kranenburg, Richard van; Kuipers, Oscar P.

    2000-01-01

    The enzymatic degradation of amino acids in cheese is believed to generate aroma compounds and therefore to be essential for flavor development. Cystathionine β-lyase (CBL) can convert cystathionine to homocysteine but is also able to catalyze an α,γ elimination. With methionine as a substrate, it p

  9. La ausencia de ftsH impide la liberación de viriones TP712 en Lactococcus lactis

    OpenAIRE

    Roces, Clara; Campelo, Ana B; Rodríguez González, Ana; García Suárez, María Pilar; Wegmann, Udo; Chapot-Chartier, Marie-Pierre; Martínez Fernández, Beatriz

    2013-01-01

    Comunicación presentada en la 7ª Reunión de la Red Temática BAL (Participación de las Bacterias Lácticas en la Salud Humana y en la Calidad Alimentaria), celebrada en Madrid los días 4 y 5 de julio de 2013.

  10. Oral Administration of Lactococcus lactis Expressing Synthetic Genes of Myelin Antigens in Decreasing Experimental Autoimmune Encephalomyelitis in Rats

    OpenAIRE

    Kasarello, Kaja; Kwiatkowska-Patzer, Barbara; Lipkowski, Andrzej W.; Bardowski, Jacek K.; Szczepankowska, Agnieszka K.

    2015-01-01

    Background Multiple sclerosis is a human autoimmunological disease that causes neurodegeneration. One of the potential ways to stop its development is induction of oral tolerance, whose effect lies in decreasing immune response to the fed antigen. It was shown in animal models that administration of specific epitopes of the three main myelin proteins – myelin oligodendrocyte glycoprotein (MOG), myelin basic protein (MBP), and proteolipid protein (PLP) – results in induction of oral tolerance ...

  11. Functional Expression of the Thiolase Gene thl from Clostridium beijerinckii P260 in Lactococcus lactis and Lactobacillus buchneri

    Science.gov (United States)

    The first step of the butanol pathway involves an acetyl-CoA acetyltransferase (ACoAAT), which controls the key branching point from acetyl-CoA to butanol. ACoAAT, also known as thiolase (EC 2.3.1.9), is encoded by the thl gene and catalyzes ligation of 2 acetyl-CoA into acetoacetyl-CoA. Bioinform...

  12. Oral immunization with Lactococcus lactis secreting attenuated recombinant staphylococcal enterotoxin B induces a protective immune response in a murine model

    OpenAIRE

    Fernandes Asensi, Giselli; Ferrari Fonseca de Sales, Nathalia; Ferreira Dutra, Fabiano; Ferreira Feijo, Daniel; Torres Bozza, Marcelo; Ulrich, Robert G.; Miyoshi, Anderson; De Morais, Katia; Ariston de Carvalho Azevedo, Vasco; Trajano Silva, Joab; Le Loir, Yves

    2013-01-01

    Background: Staphylococcus aureus is unrestrictedly found in humans and in animal species that maintain thermal homeostasis. Inadequate cleaning of processing equipment or inappropriate handling can contaminate processed food and cause severe food poisoning. Staphylococcal enterotoxin B (SEB), a potent superantigenic exotoxin, is produced by 50% of clinical isolates of S. aureus and is associated with massive food poisoning and with the induction of toxic shock syndrome. Results: A gene seque...

  13. Benchmarking Various Green Fluorescent Protein Variants in Bacillus subtilis, Streptococcus pneumoniae, and Lactococcus lactis for Live Cell Imaging

    NARCIS (Netherlands)

    Overkamp, Wout; Beilharz, Katrin; Weme, Ruud Detert Oude; Solopova, Ana; Karsens, Harma; Kovacs, Akos T.; Kok, Jan; Kuipers, Oscar P.; Veening, Jan-Willem

    2013-01-01

    Green fluorescent protein (GFP) offers efficient ways of visualizing promoter activity and protein localization in vivo, and many different variants are currently available to study bacterial cell biology. Which of these variants is best suited for a certain bacterial strain, goal, or experimental c

  14. Efficient production of secreted staphylococcal antigens in a non-lysing and proteolytically reduced Lactococcus lactis strain

    NARCIS (Netherlands)

    Neef, Jolanda; Koedijk, Danny G. A. M.; Bosma, Tjibbe; van Dijl, Jan Maarten; Buist, Girbe

    2014-01-01

    Cell surface-exposed and secreted proteins are attractive targets for vaccination against pathogenic gram-positive bacteria. To obtain sufficient amounts of such antigens, efficient protein production platforms are needed. In this study, a pipeline for the production and purification of surface-expo

  15. Morphology, genome sequence, and structural proteome of type phage P335 from Lactococcus lactis

    DEFF Research Database (Denmark)

    Labrie, Simon J.; Josephsen, Jytte; Neve, Horst;

    2008-01-01

    ) and the small terminase subunit (TerS). Four genes within this region were autonomously late transcribed and possibly under the control of Alt. Three of the four deduced proteins had similarities with proteins from Streptococcus pyogenes prophages, suggesting that P335 acquired this module from...

  16. Twofold reduction of phosphofructokinase activity in Lactococcus lactis results in strong decreases in growth rate and in glycolytic flux

    DEFF Research Database (Denmark)

    Andersen, Heidi Winterberg; Solem, Christian; Hammer, Karin;

    2001-01-01

    reduced. Surprisingly, the mutants still showed homolactic fermentation, which indicated that the limitation was different from standard glucose-limited conditions, One explanation could be that the reduced activity of phosphofructokinase resulted in the accumulation of sugar-phosphates. Indeed, when one...

  17. Variacin, a new lanthionine-containing bacteriocin produced by Micrococcus varians: comparison to lacticin 481 of Lactococcus lactis.

    OpenAIRE

    Pridmore, D; Rekhif, N; Pittet, A C; Suri, B.; Mollet, B

    1996-01-01

    A new lanthionine-containing bacteriocin, variacin, displaying a broad host range of inhibition against gram-positive food spoilage bacteria, has been identified from two strains of Micrococcus varians isolated from meat fermentations. The new bacteriocin was purified, and its amino-terminal end and total amino acid composition were determined. The structural gene was isolated and analyzed. Variacin is resistant to heat and pH conditions from 2 to 10. Its primary sequence shows significant ho...

  18. The PurR regulon in Lactococcus lactis – transcriptional regulation of the purine nucleotide metabolism and translational machinery

    DEFF Research Database (Denmark)

    Jendresen, Christian Bille; Martinussen, Jan; Kilstrup, Mogens

    2012-01-01

    motif optimization, 21 PurR-regulated genes were identified and used in a redefinition of the PurBox consensus sequence. In the process a new motif, the double-PurBox, which is present in a number of promoters and contains two partly overlapping PurBox motifs, was established. Transcriptional fusions....... This suggests that binding of the PurR protein to the PurBox takes over the role of the -35 sequence. The study has expanded the PurR regulon to include promoters in nucleotide metabolism, C(1) compound metabolism, phosphonate transport, pyrophosphatase activity, (p)ppGpp metabolism, and translation......-related functions. Of special interest is the presence of PurBox motifs in rrn promoters, suggesting a novel connection between nucleotide availability and the translational machinery....

  19. Discovery and molecular biology of the abortive infection phage resistance system AbiV from Lactococcus lactis

    DEFF Research Database (Denmark)

    Haaber, Jakob Brandt Borup

    2008-01-01

    Bakteriofager (fager) er bakteriedræbende virus som fungerer ved at sprøjte deres DNA ind i en bakteriecelle og udnytte dennes celle-apparat til at danne nye fager. Disse frigives til omgivelserne under ødelæggelse af bakteriens cellevæg hvorved cellen dør. Fager forårsager stor skade i industrie...

  20. Prophage-Cured Derivatives of Streptococcus lactis and Streptococcus cremoris

    OpenAIRE

    Gasson, Michael J.; Davies, F. Lyndon

    1980-01-01

    Prophage curing was achieved in Streptococcus lactis and Streptococcus cremoris, and the cured derivatives were shown to be indicators for their temperate bacteriophages. Relysogenization of these cured derivatives completed the first formal demonstration of the lysogenic state in lactic streptococci.

  1. Characterization of Two New Glycosyl Hydrolases from the Lactic Acid Bacterium Carnobacterium piscicola Strain BA

    OpenAIRE

    Coombs, Jonna; Brenchley, Jean E.

    2001-01-01

    Three genes with homology to glycosyl hydrolases were detected on a DNA fragment cloned from a psychrophilic lactic acid bacterium isolate, Carnobacterium piscicola strain BA. A 2.2-kb region corresponding to an α-galactosidase gene, agaA, was followed by two genes in the same orientation, bgaB, encoding a 2-kb β-galactosidase, and bgaC, encoding a structurally distinct 1.76-kb β-galactosidase. This gene arrangement had not been observed in other lactic acid bacteria, including Lactococcus la...

  2. Protective effect of clove oil-supplemented fish diets on experimental Lactococcus garvieae infection in tilapia.

    Science.gov (United States)

    Rattanachaikunsopon, Pongsak; Phumkhachorn, Parichat

    2009-09-01

    The essential oils extracted from the four herbs, cinnamon (Cinnamomum verum), clove (Syzygium aromaticum), ginger (Zingiber officinale) and holy basil (Ocimum sanctum), were investigated for their antimicrobial activity and mode of action against Lactococcus garvieae, a fish pathogenic bacteria causing lactococcosis. Of all the tested oils, clove oil had the strongest inhibitory effect and exhibited a bactericidal mode of action against the pathogenic bacterium. When an intraperitoneal infection of tilapia (Oreochromis niloticus) with L. garvieae was performed, the median lethal dose (LD(50)) was determined to be 1.78x10(2) CFU/fish. For an in vivo trial, no mortality was apparent in fish fed on the fish diets supplemented with 3% (w/w) of clove oil and with 0.5% (w/w) of oxytetracycline 5 d prior to the infection with L. garvieae. These results indicate that clove oil had a protective effect on experimental L. garvieae infection in tilapia and the potential to replace antibiotics for controlling the disease. PMID:19734665

  3. Lactococcus garvieae Endocarditis on a Prosthetic Biological Aortic Valve.

    Science.gov (United States)

    Tsur, A; Slutzki, T; Flusser, D

    2015-09-01

    Lactococcus garvieae (LG) endocarditis is a rare disease in humans. There are only about 16 reported cases in the world. We report a 76-year-old male patient with LG endocarditis. In depth interview with the patient revealed that 2 weeks prior to admission, he had eaten sushi containing raw fish. Unlike many of the other infections reported, which were on a native mitral valve, our patient's vegetation was on a prosthetic aortic valve. PMID:25295408

  4. Genome Sequence of Lactococcus garvieae 8831, Isolated from Rainbow Trout Lactococcosis Outbreaks in Spain▿

    OpenAIRE

    Aguado-Urda, Mónica; López-Campos, Guillermo H.; Gibello, Alicia; Cutuli, M. Teresa; López-Alonso, Victoria; Fernández-Garayzábal, José F.; Blanco, M. Mar

    2011-01-01

    Lactococcus garvieae is the etiological agent of lactococcosis, one of the most important disease threats to the sustainability of the rainbow trout farming industry. Here, we present the draft genome sequence of Lactococcus garvieae strain 8831, isolated from diseased rainbow trout, which is composed of 2,087,276 bp with a G+C content of 38%.

  5. Metabolic engineering of folate production in lactic acid bacteria

    OpenAIRE

    Sybesma, W.F.H.

    2003-01-01

    Folate is an essential compound in the human diet. Folate deficiency occurs frequently among certain population groups even in highly developed countries and may increase the risks for several diseases like neural tube defects, cardiovascular diseases and certain forms of cancer. The dairy starter bacterium Lactococcus lactis is able to synthesize this vitamin. The use of metabolic engineering has enabled the generation of a L. lactis strain with a more than 50-fold increased folate productio...

  6. Flavin binding to the high affinity riboflavin transporter RibU

    NARCIS (Netherlands)

    Duurkens, Hinderika; Tol, Menno B.; Geertsma, Eric R.; Permentier, Hjalmar P.; Slotboom, Dirk Jan

    2007-01-01

    The first biochemical and spectroscopic characterization of a purified membrane transporter for riboflavin ( vitamin B-2) is presented. The riboflavin transporter RibU from the bacterium Lactococcus lactis was overexpressed, solubilized, and purified. The purified transporter was bright yellow when

  7. To have neighbour's fare : extending the molecular toolbox for Streptococcus pneumoniae

    NARCIS (Netherlands)

    Kloosterman, TG; Bijlsma, J.J.E.; Kok, J; Kuipers, OP

    2006-01-01

    In past years, several useful genetic tools have been developed to study the molecular biology of Streptococcus pneumoniae. In order to extend the existing spectrum of tools, advantage was taken of the toolbox originally developed for the closely related bacterium Lactococcus lactis, which was adapt

  8. Cloning in Streptococcus lactis of plasmid-mediated UV resistance and effect on prophage stability.

    OpenAIRE

    Chopin, M C; Chopin, A; Rouault, A.; Simon, D.

    1986-01-01

    Plasmid pIL7 (33 kilobases) from Streptococcus lactis enhances UV resistance and prophage stability. A 5.4-kilobase pIL7 fragment carrying genes coding for both characters was cloned into S. lactis, using plasmid pHV1301 as the cloning vector. The recombinant plasmid was subsequently transferred to three other S. lactis strains by transformation or protoplast fusion. Cloned genes were expressed in all tested strains.

  9. Cloning in Streptococcus lactis of plasmid-mediated UV resistance and effect on prophage stability

    International Nuclear Information System (INIS)

    Plasmid pIL7 (33 kilobases) from Streptococcus lactis enhances UV resistance and prophage stability. A 5.4-kilobase pIL7 fragment carrying genes coding for both characters was cloned into S. lactis, using plasmid pHV1301 as the cloning vector. The recombinant plasmid was subsequently transferred to three other S. lactis strains by transformation or protoplast fusion. Cloned genes were expressed in all tested strains

  10. Bifidobacterium animalis subsp. lactis ATCC 27673 Is a Genomically Unique Strain within Its Conserved Subspecies

    OpenAIRE

    Loquasto, Joseph R.; Barrangou, Rodolphe; Dudley, Edward G.; Stahl, Buffy; Chen, Chun; Roberts, Robert F.

    2013-01-01

    Many strains of Bifidobacterium animalis subsp. lactis are considered health-promoting probiotic microorganisms and are commonly formulated into fermented dairy foods. Analyses of previously sequenced genomes of B. animalis subsp. lactis have revealed little genetic diversity, suggesting that it is a monomorphic subspecies. However, during a multilocus sequence typing survey of Bifidobacterium, it was revealed that B. animalis subsp. lactis ATCC 27673 gave a profile distinct from that of the ...

  11. Regulation of the Glutamate-Glutamine Transport System by Intracellular pH in Streptococcus lactis

    NARCIS (Netherlands)

    POOLMAN, B; HELLINGWERF, KJ; KONINGS, WN

    1987-01-01

    Various methods of manipulation of the intracellular pH in Streptococcus lactis result in a unique relationship between the rate of glutamate and glutamine transport and the cytoplasmic pH. The initial rate of glutamate uptake by S. lactis cells increases more than 30-fold when the intracellular pH

  12. Infective endocarditis with Lactococcus garvieae in Japan: a case report

    Directory of Open Access Journals (Sweden)

    Isonuma Hiroshi

    2011-08-01

    Full Text Available Abstract Introduction Lactococcus garvieae is a well-recognized fish pathogen, and it is considered a rare pathogen with low virulence in human infection. We describe the 11th case of L. garvieae infective endocarditis reported in the literature, and the first reported case in Japan. Case presentation We report a case of a 55-year-old Japanese woman who had native valve endocarditis with L. garvieae. The case was complicated by renal infarction, cerebral infarction, and mycotic aneurysms. After anti-microbial treatment, she was discharged from the hospital and is now well while being monitored in the out-patient clinic. Conclusion We encountered a case of L. garvieae endocarditis that occurred in a native valve of a healthy woman. The 16S ribosomal RNA gene sequencing was useful for the identification of this pathogen. Although infective endocarditis with L. garvieae is uncommon, it is possible to treat high virulence clinically.

  13. Physiological Studies of β-Galactosidase Induction in Kluyveromyces lactis

    OpenAIRE

    Dickson, Robert C.; Markin, Jennifer S.

    1980-01-01

    We examined the kinetics of β-galactosidase (EC 3.2.1.23) induction in the yeast Kluyveromyces lactis. Enzyme activity began to increase 10 to 15 min, about 1/10 of a cell generation, after the addition of inducer and continued to increase linearly for from 7 to 9 cell generations before reaching a maximum, some 125- to 150-fold above the basal level of uninduced cells. Thereafter, as long as logarithmic growth was maintained, enzyme levels remained high, but enzyme levels dropped to a value ...

  14. Isolation and characterization of an Enterococcus-like bacterium causing muscle necrosis and mortality in Macrobrachium rosenbergii in Taiwan.

    Science.gov (United States)

    Cheng, W; Chen, J C

    1998-10-01

    A Gram-positive, ovoid, diplococoid bacterium tentatively identified as Enterococcus-like was isolated from diseased Macrobrachium rosenbergii in Taiwanese aquaculture ponds. The diseased prawns displayed poor growth, anorexia, inactivity, opaque and whitish musculature, and mortality. In histological preparations, melanized hemocytic granulomas were seen in the connective tissue around hemal sinuses together with hemocytic aggregation in necrotic musculature. Five isolates of diplococci were collected from diseased prawns at 4 farms and these were evaluated for 93 characteristics including morphology, physiology, biochemistry and sensitivity to antibiotics. The results indicated that the isolates belonged to a single species. They grew in 0.5 to 6.0% NaCl, at 10 to 40 degrees C, at pH 9.6 and on bile esculin medium, gave positive pyrrolidonylarylamidase, arginine dehydrolase and Voges-Proskauer tests, were resistant to bacitracin and SXT, and were CAMP-negative and non-hemolytic on sheep blood agar. These findings indicated an Enterococcus-like bacterium closely related to Enterococcus seriolicida (recently reduced to synonymy with Lactococcus garvieae). Experimental injection of 3 x 10(5) cells of strain KM002 of this Enterococcus-like bacterium into the ventral sinus of the prawn cephalothorax caused 100% mortality in 11 d, and induced muscular necrosis and hepatopancreatitis, gross signs and histopathology similar to those observed in the naturally infected prawns. It was concluded that this Enterococcus-like bacterium was the etiological agent associated with mortality of the farmed, diseased prawns. PMID:9828405

  15. Bifidobacterium lactis attenuates onset of inflammation in a murine model of colitis

    Institute of Scientific and Technical Information of China (English)

    David Philippe; Stéphanie Blum; Laurent Favre; Francis Foata; Oskar Adolfsson; Genevieve Perruisseau-Carrier; Karine Vidal; Gloria Reuteler; Johanna Dayer-Schneider; Christoph Mueller

    2011-01-01

    AIM: To assess the anti-inflammatory effect of the probiotic Bifidobacterium lactis (B. lactis ) in an adoptive transfer model of colitis. METHODS: Donor and recipient mice received either B. lactis or bacterial culture medium as control (deMan Rogosa Sharpe) in drinking water for one week prior to transfer of a mix of naive and regulatory T cells until sacrifice. RESULTS: All recipient mice developed signs of colonic inflammation, but a significant reduction of weight loss was observed in B. lactis -fed recipient mice compared to control mice. Moreover, a trend toward a diminution of mucosal thickness and attenuated epithelial damage was revealed. Colonic expression of pro-inflammatory and T cell markers was significantly reduced in B. lactis - fed recipient mice compared to controls. Concomitantly, forkhead box protein 3, a marker of regulatory T cells, was significantly up-regulated by B. lactis . CONCLUSION: Daily oral administration of B. lactis was able to reduce inflammatory and T cells mediators and to promote regulatory T cells specific markers in a mouse model of colitis.

  16. Two Uptake Systems for Fructose in Lactococcus lactis subsp. cremoris FD1 Produce Glycolytic and Gluconeogenic Fructose Phosphates and Induce Oscillations in Growth and Lactic Acid Formation

    OpenAIRE

    Benthin, Stig; Nielsen, Jens; Villadsen, John

    1993-01-01

    Fructose transport in lactococci is mediated by two phosphotransferase systems (PTS). The constitutive mannose PTS has a broad specificity and may be used for uptake of fructose with a fructose saturation constant (KFru) of 0.89 mM, giving intracellular fructose 6-phosphate. The inducible fructose PTS has a very small saturation constant (KFru,

  17. Dispersive solid phase extraction combined with ion-pair ultra high-performance liquid chromatography tandem mass spectrometry for quantification of nucleotides in Lactococcus lactis

    DEFF Research Database (Denmark)

    Magdenoska, Olivera; Martinussen, Jan; Thykær, Jette;

    2013-01-01

    Analysis of intracellular metabolites in bacteria is of utmost importance for systems biology and at the same time analytically challenging due to the large difference in concentrations, multiple negative charges, and high polarity of these compounds. To challenge this, a method based on dispersive...

  18. Shewanella oneidensis in a lactate-fed pure-culture and a glucose-fed co-culture with Lactococcus lactis with an electrode as electron acceptor

    Science.gov (United States)

    Bioelectrochemical systems (BESs) employing mixed microbial communities as biocatalysts are gaining importance as potential renewable energy, bioremediation, or biosensing devices. While we are beginning to understand how individual microbial species interact with an electrode as electron donor, li...

  19. Characterization of the Function and Interaction of Proteins Involved in Exopolysaccharide Synthesis in Streptococcus thermophilus, Streptococcus iniae, and Lactococcus lactis subsp. cremoris

    OpenAIRE

    Cefalo, Angela D.

    2012-01-01

    Amino acid residues that are important for metal binding and catalysis in Grampositive phosphotyrosine phosphatases were identified in Streptococcus thermophilus Wzh/EpsB proteins. The Wzh protein from S. thermophilus MR-1C was purified after heterologous expression and tested for phosphatase activity against synthetic phosphotyrosine and phosphoserine/threonine peptides. The purified Wzh protein was able to remove phosphate from both phosphotyrosine peptides tested and the phosphatase activi...

  20. Comparative genome-based identification of a cell wall-anchored protein from Lactobacillus plantarum increases adhesion of Lactococcus lactis to human epithelial cells

    OpenAIRE

    ZHANG, BO; Zuo, Fanglei; Yu, Rui; Zeng, Zhu; Ma, Huiqin; Chen, Shangwu

    2015-01-01

    Adhesion to host cells is considered important for Lactobacillus plantarum as well as other lactic acid bacteria (LAB) to persist in human gut and thus exert probiotic effects. Here, we sequenced the genome of Lt. plantarum strain NL42 originating from a traditional Chinese dairy product, performed comparative genomic analysis and characterized a novel adhesion factor. The genome of NL42 was highly divergent from its closest neighbors, especially in six large genomic regions. NL42 harbors a t...

  1. Genetic investigation within Lactococcus garvieae revealed two genomic lineages.

    Science.gov (United States)

    Ferrario, Chiara; Ricci, Giovanni; Borgo, Francesca; Rollando, Alessandro; Fortina, Maria Grazia

    2012-07-01

    The diversity of a collection of 49 Lactococcus garvieae strains, including isolates of dairy, fish, meat, vegetable and cereal origin, was explored using a molecular polyphasic approach comprising PCR-ribotyping, REP and RAPD-PCR analyses and a multilocus restriction typing (MLRT) carried out on six partial genes (atpA, tuf, dltA, als, gapC, and galP). This approach allowed high-resolution cluster analysis in which two major groups were distinguishable: one group included dairy isolates, the other group meat isolates. Unexpectedly, of the 12 strains coming from fish, four grouped with dairy isolates, whereas the others with meat isolates. Likewise, strains isolated from vegetables allocated between the two main groups. These findings revealed high variability within the species at both gene and genome levels. The observed genetic heterogeneity among L. garvieae strains was not entirely coherent with the ecological niche of origin of the strains, but rather supports the idea of an early separation of L. garvieae population into two independent genomic lineages. PMID:22568590

  2. Single Bacterium Detection Using Sers

    Science.gov (United States)

    Gonchukov, S. A.; Baikova, T. V.; Alushin, M. V.; Svistunova, T. S.; Minaeva, S. A.; Ionin, A. A.; Kudryashov, S. I.; Saraeva, I. N.; Zayarny, D. A.

    2016-02-01

    This work is devoted to the study of a single Staphylococcus aureus bacterium detection using surface-enhanced Raman spectroscopy (SERS) and resonant Raman spectroscopy (RS). It was shown that SERS allows increasing sensitivity of predominantly low frequency lines connected with the vibrations of Amide, Proteins and DNA. At the same time the lines of carotenoids inherent to this kind of bacterium are well-detected due to the resonance Raman scattering mechanism. The reproducibility and stability of Raman spectra strongly depend on the characteristics of nanostructured substrate, and molecular structure and size of the tested biological object.

  3. Heterologous expression of Aspergillus terreus fructosyltransferase in Kluyveromyces lactis.

    Science.gov (United States)

    Spohner, Sebastian C; Czermak, Peter

    2016-06-25

    Fructo-oligosaccharides are prebiotic and hypocaloric sweeteners that are usually extracted from chicory. They can also be produced from sucrose using fructosyltransferases, but the only commercial enzyme suitable for this purpose is Pectinex Ultra, which is produced with Aspergillus aculeatus. Here we used the yeast Kluyveromyces lactis to express a secreted recombinant fructosyltransferase from the inulin-producing fungus Aspergillus terreus. A synthetic codon-optimised version of the putative β-fructofuranosidase ATEG 04996 (XP 001214174.1) from A. terreus NIH2624 was secreted as a functional protein into the extracellular medium. At 60°C, the purified A. terreus enzyme generated the same pattern of oligosaccharides as Pectinex Ultra, but at lower temperatures it also produced oligomers with up to seven units. We achieved activities of up to 986.4U/mL in high-level expression experiments, which is better than previous reports of optimised Aspergillus spp. fermentations. PMID:27084521

  4. Bifidobacterium lactis 420 and fish oil enhance intestinal epithelial integrity in Caco-2 cells.

    Science.gov (United States)

    Mokkala, Kati; Laitinen, Kirsi; Röytiö, Henna

    2016-03-01

    Increased intestinal permeability is a predisposing factor for low-grade inflammation-associated conditions, including obesity and type 2 diabetes. Dietary components may influence intestinal barrier integrity. We hypothesized that the dietary supplements Bifidobacterium lactis 420, Lactobacillus rhamnosus HN001, and fish oil have beneficial impacts on intestinal barrier integrity. In addition, we hypothesized that the coadministration of these components results in synergistic benefits to the integrity of the intestinal barrier. To study this, we investigated the impact of cell-free culture supernatant from dietary supplements B lactis 420 and L rhamnosus HN001, and fish oil, separately and in combination, on intestinal permeability in a CaCo-2 cell model. Administered separately, both B lactis 420 supernatant and fish oil significantly increased the integrity of the intestinal epithelial barrier, as determined by an increase in transepithelial electrical resistance (TEER), whereas L rhamnosus did not. The TEER increase with B lactis 420 was dose dependent. Interestingly, a combination of B lactis 420 supernatant and fish oil negated the increase in TEER of the single components. mRNA expression of tight junction proteins, measured by real-time quantitative polymerase chain reaction, was not altered, but the mRNA expression of myosin light chain kinase increased after fish oil treatment. To conclude, single dietary components, namely, B lactis 420 and fish oil, induced beneficial effects on intestinal barrier integrity in vitro, whereas a combination of 2 beneficial test compounds resulted in a null effect. PMID:26923511

  5. Glycosylation in secreted proteins from yeast Kluyveromyces lactis

    International Nuclear Information System (INIS)

    Full text: The nutritional status of a cell culture affects either the expression or the traffic of a number of proteins. The identification of the physiological conditions which favor protein secretion has important biotechnological consequences in designing systems for recombinant extracellular protein industrial production. Yeast Kluyvromyces lactis has been cultured in a continuous stirring tank bioreactor (CSTR) under nitrogen limitation at growth rates (0.03 h-1 and 0.09 h-1) close to either exponential or stationary batch growth phases, respectively the objective was to investigate the extracellular glycoproteins at these two level of nitrogen limitation. Proteins from free cell extracts were separated by gradient SDS-PAGE (5-15%) and two-dimensional chromatography, and were analyzed by mass spectrometry (MALDI-TOF-TOF-MS). In SDS-PAGE analysis, differences in extracellular proteome were visualized: different proteins profiles at these two growth rates. The 0.09 h-1 growth rate showed larger number of bands using colloidal Coma ssie Blue staining. Different bands were detected at these two growth rates when the PAS assay for glycoprotein detection in polyacrylamide gel was used. The two-dimensional chromatogram profiles were comparatively distinguished between the 0.03 h-1 and 0.09 h-1 growth rate samples. Protein peaks from the second dimension, were subjected to mass spectrometry. The mass spectrums visualized showed glycosylated proteins with N-acetylglucosamine molecules and 8, 9 or 15 hexoses molecules. Comparisons between the proteins averaged mass values with the deduced proteins masses from K. lactis secreted proteins database indicated possible post-translational modifications, such as post-translational proteolysis, acetylation, deamidation and myristoylation

  6. Glycosylation in secreted proteins from yeast Kluyveromyces lactis

    Energy Technology Data Exchange (ETDEWEB)

    Santos, A.V.; Passos, F.M.L. [Universidade Federal de Vicosa (UFV), MG (Brazil). Dept. de Microbiologia. Lab. de Fisiologia de Microrganismos; Azevedo, B.R.; Pimenta, A.M.C.; Santoro, M.M. [Universidade Federal de Minas Gerais (UFMG), Belo Horizonte, MG (Brazil). Dept. de Bioquimica e Imunologia. Lab. de Enzimologia e Fisico-Quimica de Proteina

    2008-07-01

    Full text: The nutritional status of a cell culture affects either the expression or the traffic of a number of proteins. The identification of the physiological conditions which favor protein secretion has important biotechnological consequences in designing systems for recombinant extracellular protein industrial production. Yeast Kluyvromyces lactis has been cultured in a continuous stirring tank bioreactor (CSTR) under nitrogen limitation at growth rates (0.03 h{sup -1} and 0.09 h{sup -1}) close to either exponential or stationary batch growth phases, respectively the objective was to investigate the extracellular glycoproteins at these two level of nitrogen limitation. Proteins from free cell extracts were separated by gradient SDS-PAGE (5-15%) and two-dimensional chromatography, and were analyzed by mass spectrometry (MALDI-TOF-TOF-MS). In SDS-PAGE analysis, differences in extracellular proteome were visualized: different proteins profiles at these two growth rates. The 0.09 h-1 growth rate showed larger number of bands using colloidal Coma ssie Blue staining. Different bands were detected at these two growth rates when the PAS assay for glycoprotein detection in polyacrylamide gel was used. The two-dimensional chromatogram profiles were comparatively distinguished between the 0.03 h{sup -1} and 0.09 h{sup -1} growth rate samples. Protein peaks from the second dimension, were subjected to mass spectrometry. The mass spectrums visualized showed glycosylated proteins with N-acetylglucosamine molecules and 8, 9 or 15 hexoses molecules. Comparisons between the proteins averaged mass values with the deduced proteins masses from K. lactis secreted proteins database indicated possible post-translational modifications, such as post-translational proteolysis, acetylation, deamidation and myristoylation.

  7. Complete Genome Sequence of Nonagglutinating Lactococcus garvieae Strain 122061 Isolated from Yellowtail in Japan

    Science.gov (United States)

    Nishiki, Issei; Oinaka, Daisaku; Iwasaki, Yuki; Yasuike, Motoshige; Nakamura, Yoji; Yoshida, Terutoyo; Nagai, Satoshi; Katoh, Masaya; Kobayashi, Takanori

    2016-01-01

    Nonagglutinating Lactococcus garvieae has been isolated from diseased farmed yellowtail in Japan since 2012. In this study, the complete genome and plasmid sequence of nonagglutinating L. garvieae strain 122061 was determined, to our knowledge, for the first time. PMID:27389264

  8. Lactose metabolism in Streptococcus lactis: studies with a mutant lacking glucokinase and mannose-phosphotransferase activities

    International Nuclear Information System (INIS)

    A mutant of Streptococcus lactis 133 has been isolated that lacks both glucokinase and phosphoenolpyruvate-dependent mannose- phosphotransferase (mannose-PTS) activities. The double mutant S. lactis 133 mannose-PTSd GK- is unable to utilize either exogenously supplied or intracellularly generated glucose for growth. Fluorographic analyses of metabolites formed during the metabolism of [14C]lactose labeled specifically in the glucose or galactosyl moiety established that the cells were unable to phosphorylate intracellular glucose. However, cells of S. lactis 133 mannose-PTSd GK- readily metabolized intracellular glucose 6-phosphate, and the growth rates and cell yield of the mutant and parental strains on sucrose were the same. During growth on lactose, S. lactis 133 mannose-PTSd GK- fermented only the galactose moiety of the disaccharide, and 1 mol of glucose was generated per mol of lactose consumed. For an equivalent concentration of lactose, the cell yield of the mutant was 50% that of the wild type. The specific rate of lactose utilization by growing cells of S. lactis 133 mannose-PTSd GK- was ca. 50% greater than that of the wild type, but the cell doubling times were 70 and 47 min, respectively. High-resolution 31P nuclear magnetic resonance studies of lactose transport by starved cells of S. lactis 133 and S. lactis 133 mannose-PTSd GK- showed that the latter cells contained elevated lactose-PTS activity. Throughout exponential growth on lactose, the mutant maintained an intracellular steady-state glucose concentration of 100 mM

  9. Lactose metabolism in Streptococcus lactis: studies with a mutant lacking glucokinase and mannose-phosphotransferase activities

    Energy Technology Data Exchange (ETDEWEB)

    Thompson, J.; Chassy, B.M.; Egan, W.

    1985-04-01

    A mutant of Streptococcus lactis 133 has been isolated that lacks both glucokinase and phosphoenolpyruvate-dependent mannose- phosphotransferase (mannose-PTS) activities. The double mutant S. lactis 133 mannose-PTSd GK- is unable to utilize either exogenously supplied or intracellularly generated glucose for growth. Fluorographic analyses of metabolites formed during the metabolism of (/sup 14/C)lactose labeled specifically in the glucose or galactosyl moiety established that the cells were unable to phosphorylate intracellular glucose. However, cells of S. lactis 133 mannose-PTSd GK- readily metabolized intracellular glucose 6-phosphate, and the growth rates and cell yield of the mutant and parental strains on sucrose were the same. During growth on lactose, S. lactis 133 mannose-PTSd GK- fermented only the galactose moiety of the disaccharide, and 1 mol of glucose was generated per mol of lactose consumed. For an equivalent concentration of lactose, the cell yield of the mutant was 50% that of the wild type. The specific rate of lactose utilization by growing cells of S. lactis 133 mannose-PTSd GK- was ca. 50% greater than that of the wild type, but the cell doubling times were 70 and 47 min, respectively. High-resolution /sup 31/P nuclear magnetic resonance studies of lactose transport by starved cells of S. lactis 133 and S. lactis 133 mannose-PTSd GK- showed that the latter cells contained elevated lactose-PTS activity. Throughout exponential growth on lactose, the mutant maintained an intracellular steady-state glucose concentration of 100 mM.

  10. The prophylactic effect of probiotic Enterococcus lactis IW5 against different human cancer cells

    Directory of Open Access Journals (Sweden)

    YOUSEF eNAMI

    2015-11-01

    Full Text Available Enterococcus lactis IW5 was obtained from human gut and the potential probiotic characteristics of this organism were then evaluated. Results showed that this strain was highly resistant to low pH and high bile salt and adhered strongly to Caco-2 human epithelial colorectal cell lines. The supernatant of E. lactis IW5 strongly inhibited the growth of several pathogenic bacteria and decreased the viability of different cancer cells, such as HeLa, AGS, HT-29, and MCF-7. Conversely, E. lactis IW5 did not inhibit the viability of normal FHs-74 cells. This strain did not generate toxic enzymes, including β-glucosidase, β-glucuronidase, and N-acetyl-β-glucosaminidase and was highly susceptible to ampicillin, gentamycin, penicillin, vancomycin, clindamycin, sulfamethoxazol, and chloramphenicol but resistant to erythromycin and tetracyclin. This study provided evidence for the effect of E. lactis IW5 on cancer cells. Therefore, E. lactis IW5, as a bioactive therapeutics, should be subjected to other relevant tests to verify the therapeutic suitability of this strain for clinical applications.

  11. Biotechnological and safety characterization of Enterococcus lactis, a recently described species of dairy origin.

    Science.gov (United States)

    Morandi, Stefano; Silvetti, Tiziana; Brasca, Milena

    2013-01-01

    The biotechnological and safety properties of a recently described enterococcal species, Enterococcus lactis, were investigated. With regard to the technological properties, in milk all the strains tested had weak acidifying and proteolytic activities, generally medium reduction activity over 24 h (-102 mV hyl, esp, ace, efaA, hdc and tdc) was investigated by PCR and no virulence determinants were detected. This study highlights that the recently described E. lactis may be a potential source of novel strains with interesting features that could be used for fermented dairy foods. PMID:22961639

  12. Crystallization and preliminary X-ray crystallographic analysis of β-galactosidase from Kluyveromyces lactis

    International Nuclear Information System (INIS)

    β-Galactosidase from K. lactis has been expressed in S. cerevisiae, purified by affinity chromatography and crystallized in its native form. β-Galactosidase from Kluyveromyces lactis catalyses the hydrolysis of the β-galactosidic linkage in lactose. Owing to its many industrial applications, the biotechnological potential of this enzyme is substantial. This protein has been expressed in yeast and purified for crystallization trials. However, optimization of the best crystallization conditions yielded crystals with poor diffraction quality that precluded further structural studies. Finally, the crystal quality was improved using the streak-seeding technique and a complete diffraction data set was collected at 2.8 Å resolution

  13. Evaluation of Immunomodulatory Effects of Lactic Acid Bacteria in Turbot (Scophthalmus maximus)

    OpenAIRE

    Villamil, L.; Tafalla, C.; Figueras, A.; Novoa, B.

    2002-01-01

    In the present work, the effects of several lactic acid bacteria on the immune response of turbot (Scophthalmus maximus) macrophages have been studied both in vitro and in vivo. Out of six lactic acid bacterial strains tested, only heat-killed Lactococcus lactis significantly increased the turbot head kidney macrophage chemiluminescent (CL) response after 24 h of incubation. Nitric oxide (NO) was also significantly enhanced by this bacterium after 72 h of incubation with either viable (103 an...

  14. 21 CFR 184.1388 - Lactase enzyme preparation from Kluyveromyces lactis.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Lactase enzyme preparation from Kluyveromyces... GENERALLY RECOGNIZED AS SAFE Listing of Specific Substances Affirmed as GRAS § 184.1388 Lactase enzyme preparation from Kluyveromyces lactis. (a) This enzyme preparation is derived from the...

  15. Study of physiological properties of some probiotics in multiple cultures with mesophilic lactic acid bacteria by Flora Danica Ch. Hansen commercial starter

    OpenAIRE

    DANIELA PARASCHIV; AIDA VASILE; MADALINA CONSTANTIN; ALEXANDRU CIOBANU; GABRIELA BAHRIM

    2011-01-01

    The aim of this study was to establish the growth ability and stability of probiotic strains Lactobacillus acidophilus (commercial code La-5®), Lactobacillus casei ssp. paracasei (commercial code L. casei 431®) and Bifidobacterium bifidus (commercial code BB-12®) in multiple cultures with mesophilic lactic bacteria, Lactococcus lactis ssp. cremoris, Lactococcus lactis ssp. lactis, Lactococcus lactis ssp. diacetylactis and Leuconostoc mesenteroides spp. cremoris, as Flora Danica Chr. Hansen co...

  16. Genetic Dissection of the Kluyveromyces lactis Telomere and Evidence for Telomere Capping Defects in TER1 Mutants with Long Telomeres

    OpenAIRE

    Underwood, Dana H.; Carroll, Coleen; McEachern, Michael J.

    2004-01-01

    In the yeast Kluyveromyces lactis, the telomeres are composed of perfect 25-bp repeats copied from a 30-nucleotide RNA template defined by 5-nucleotide terminal repeats. A genetic dissection of the K. lactis telomere was performed by using mutant telomerase RNA (TER1) alleles to incorporate mutated telomeric repeats. This analysis has shown that each telomeric repeat contains several functional regions, some of which may physically overlap. Mutations in the terminal repeats of the template RN...

  17. Secretion and properties of a hybrid Kluyveromyces lactis-Aspergillus niger β-galactosidase

    Directory of Open Access Journals (Sweden)

    Becerra Manuel

    2006-12-01

    Full Text Available Abstract Background The β-galactosidase from Kluyveromyces lactis is a protein of outstanding biotechnological interest in the food industry and milk whey reutilization. However, due to its intracellular nature, its industrial production is limited by the high cost associated to extraction and downstream processing. The yeast-system is an attractive method for producing many heterologous proteins. The addition of a secretory signal in the recombinant protein is the method of choice to sort it out of the cell, although biotechnological success is not guaranteed. The cell wall acting as a molecular sieve to large molecules, culture conditions and structural determinants present in the protein, all have a decisive role in the overall process. Protein engineering, combining domains of related proteins, is an alternative to take into account when the task is difficult. In this work, we have constructed and analyzed two hybrid proteins from the β-galactosidase of K. lactis, intracellular, and its Aspergillus niger homologue that is extracellular. In both, a heterologous signal peptide for secretion was also included at the N-terminus of the recombinant proteins. One of the hybrid proteins obtained has interesting properties for its biotechnological utilization. Results The highest levels of intracellular and extracellular β-galactosidase were obtained when the segment corresponding to the five domain of K. lactis β-galactosidase was replaced by the corresponding five domain of the A. niger β-galactosidase. Taking into account that this replacement may affect other parameters related to the activity or the stability of the hybrid protein, a thoroughly study was performed. Both pH (6.5 and temperature (40°C for optimum activity differ from values obtained with the native proteins. The stability was higher than the corresponding to the β-galactosidase of K. lactis and, unlike this, the activity of the hybrid protein was increased by the presence

  18. Complete genome sequence and description of Lactococcus garvieae M14 isolated from Algerian fermented milk

    Directory of Open Access Journals (Sweden)

    M. Moumene

    2016-03-01

    Full Text Available We describe using a polyphasic approach that combines proteomic by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF analysis, genomic data and phenotypic characterization the features of Lactococcus garvieae strain M14 newly isolated from the fermented milk (known as raib of an Algerian cow. The 2 188 835 bp containing genome sequence displays a metabolic capacity to form acid fermentation that is very useful for industrial applications and encodes for two bacteriocins responsible for its eventual bioprotective properties.

  19. Study of the transgalactosylation activity of ß-galactosidase from a new strain Kluyveromyces lactis 3

    Directory of Open Access Journals (Sweden)

    ILIA ILIEV

    2012-01-01

    Full Text Available Beta-galactosidase (EC.3.2.1.23 is an important enzyme industrially used for the hydrolysis of lactose from milk and milk whey for several applications. Lately, the importance of this enzyme was enhanced by its galactosyltransferase activity, which is responsible for synthesis of transgalactosylated oligosaccharides that act as prebiotics with several beneficial effects on the consumers. ß-Galactosidase production by Kluyveromyces lactis 3 was studied in shake flask culture. The highest enzymatic activity was obtained at 10-th hour of the fermentation. The optimum temperature for transferase activity was 50°C. When incubated with 30% lactose in 50 mM phosphate buffer (pH 6.0 the enzyme can synthesize up to 41% galacto-oligosaccharides (GalOS. β-Galactosidase from strain Kluyveromyces lactis 3 produces mainly oligosaccharides with degree of polymerization (DP 6 at 40°C and with DP 3 at 50°C.

  20. Stable isotope labeling of protein by Kluyveromyces lactis for NMR study

    Energy Technology Data Exchange (ETDEWEB)

    Sugiki, Toshihiko [Japan Biological Informatics Consortium (JBiC) (Japan); Shimada, Ichio, E-mail: shimada@iw-nmr.f.u-tokyo.ac.jp; Takahashi, Hideo [Biomedicinal Information Research Center (BIRC), National Institute of Advanced Industrial Science and Technology (AIST) (Japan)], E-mail: hid.takahashi@aist.go.jp

    2008-11-15

    Stable isotope labeling for proteins of interest is an important technique in structural analyses of proteins by NMR spectroscopy. Escherichia coli is one of the most useful protein expression systems for stable isotope labeling because of its high-level protein expression and low costs for isotope-labeling. However, for the expression of proteins with numerous disulfide-bonds and/or post-translational modifications, E. coli systems are not necessarily appropriate. Instead, eukaryotic cells, such as yeast Pichia pastoris, have great potential for successful production of these proteins. The hemiascomycete yeast Kluyveromyces lactis is superior to the methylotrophic yeast P. pastoris in some respects: simple and rapid transformation, good reproducibility of protein expression induction and easy scale-up of culture. In the present study, we established a protein expression system using K. lactis, which enabled the preparation of labeled proteins using glucose and ammonium chloride as a stable isotope source.

  1. Stable isotope labeling of protein by Kluyveromyces lactis for NMR study

    International Nuclear Information System (INIS)

    Stable isotope labeling for proteins of interest is an important technique in structural analyses of proteins by NMR spectroscopy. Escherichia coli is one of the most useful protein expression systems for stable isotope labeling because of its high-level protein expression and low costs for isotope-labeling. However, for the expression of proteins with numerous disulfide-bonds and/or post-translational modifications, E. coli systems are not necessarily appropriate. Instead, eukaryotic cells, such as yeast Pichia pastoris, have great potential for successful production of these proteins. The hemiascomycete yeast Kluyveromyces lactis is superior to the methylotrophic yeast P. pastoris in some respects: simple and rapid transformation, good reproducibility of protein expression induction and easy scale-up of culture. In the present study, we established a protein expression system using K. lactis, which enabled the preparation of labeled proteins using glucose and ammonium chloride as a stable isotope source

  2. Purification and Characterization of a Bacteriocin Produced by Lactobacillus lactis Isolated from Marine Environment

    Directory of Open Access Journals (Sweden)

    P. Manivasagan

    2010-03-01

    Full Text Available Bacteriocin producing Lactobacillus lactis strain isolated from marine environment, showed broadrange of antibacterial activity against some major food borne pathogens. Maximum bacteriocin production wasobserved at 30°C , pH 6.0 and 1.5% sodium chloride solution. In addition of enzymes, "-amylase, DNase,RNase and lipase were slightly positive effect bacteriocin production. Proteinase K and pepsin were stronglyinhibited bacteriocin production. Among detergents, Sodium dodecyl sulphate (SDS, Tween 80 and TritoneX-100 stimulated bacteriocin production and strongly inhibited by EDTA and urea. The bacteriocin has purifiedby ammonium sulphate precipitate and ion exchange (DEAE cellulose chromatography. Biochemically it waspure protein moiety and the molecular weight was 94 kDa. The study revealed the possibility of usingbacteriocin as a food preservative and the L. lactis strain as probiotic.

  3. Effect of composite yogurt enriched with acacia fiber and Bifidobacterium lactis

    Institute of Scientific and Technical Information of China (English)

    Yang Won Min; Sang Un Park; Yeon Sil Jang; Young-Ho Kim; Poong-Lyul Rhee; Seo Hyun Ko; Nami Joo

    2012-01-01

    AIM:To investigate whether composite yogurt with acacia dietary fiber and Bifidobacterium lactis (B.lactis)has additive effects in irritable bowel syndrome (IBS).METHODS:A total of 130 patients were randomly allocated to consume,twice daily for 8 wk,either the composite yogurt or the control product.The composite yogurt contained acacia dietary fiber and high-dose B.lactis together with two classic yogurt starter cultures.Patients were evaluated using the visual analog scale via a structured questionnaire administered at baseline and after treatment.RESULTS:Improvements in bowel habit satisfaction and overall IBS symptoms from baseline were significantly higher in the test group than in the control group (27.16 vs 15.51,P =0.010,64.2 ± 17.0 vs 50.4 ± 20.5,P < 0.001; respectively).In constipation-predominant IBS,improvement in overall IBS symptoms was significantly higher in the test group than in the control group (72.4 ± 18.4 vs 50.0 ± 21.8,P < 0.001).In patients with diarrhea-predominant IBS,improvement in bowel habit satisfaction from baseline was significantly higher in the test group than in the control group (32.90 vs 7.81,P =0.006).CONCLUSION:Our data suggest that composite yogurt enriched with acacia fiber and B.lactis has greater therapeutic effects in patients with IBS than standard yogurt.

  4. Induced mutants of Streptococcus lactis by gamma irradiation and its effect on milk acidity

    International Nuclear Information System (INIS)

    Streptococus lactis was exposed to different doses of gamma-irradiation (10, 50, 100 and 150 Kr). The results of acidity production in sterilized milk inoculated by isolates from radiation treatments and control could be summarized in the following: 1. The mean acidity produced by S. lactis isolates after irradiation at 10 Kr increased to be 0.66% than that of control isolates (0.62%). The acidity produced by the isolates of the 50 Kr treatment showed more increment to reach the peak (0.7%). Thereafter, acidity production decreased by isolates of the 100 Kr (0.53%) and 150 Kr (0.51%) treatments. Heme, the 50 Kr treatment could be considered activation dose to S. lactis starter for acid production. 2. Two mutants were selected. Acidity production by mutant I (from 10 Kr treatment) was 0.95%, and that of mutant II (from 50 Kr treatment) was 1.0%, while acid production by the parent S. lactis culture was 0.62%. Concerning the stability of the isolates, it was found that acid production by mutant I and mutant II slightly decreased by time. The mutants were re-irradiated after 37 and 60 days at doses 10, 25 and 50 Kr. Acid production in milk by isolates of the radiation treatments was determined. The following results were obtained: -The re-irradiation of the mutants decreased the ability of the isolates for acid production than that of parent mutants. -The re-irradiation of the mutants after 60 days yielded isolates which showed more reduction in acid produced than of isolates obtained from re-irridation of the mutants after 37-days. -The higher the dose of the re-irradiation of the mutants, the lower the mean of acid production by isolates of the treatment

  5. Effect of Bifidobacterium lactis LKM 512 yogurt on fecal microflora in middle to old aged persons

    OpenAIRE

    Matsumoto, Mitsuharu; Tadenuma, Tadashi; Nakamura, Kyoko; Kume, Hitoshi; Imai, Tetsuya; Kihara, Ritsuko; Watanabe, Masatoshi; Benno, Yoshimi

    2011-01-01

    Effect of yogurt (LKM512 yogurt) prepared Bifidobacterium lactis LKM 512, Lactobacillus delbrueckii subsp. bulgaricus LKM 1759 and Streptococcus thermophilus LKM 1742 on fecal microflora in 11 volunteers (six males and five females, average age 76.9 years) given this yogurt 100 g/day for 2 weeks were determined. At week 2 of consumption, the number of bifidobacteria in the fecal microflora increased significantly (p<0.05). Meanwhile, the frequencies of occurrence of peptostreptococci, veil...

  6. Structural basis for arabinoxylo-oligosaccharide capture by the probiotic Bifidobacterium animalis subsp lactis Bl-04

    OpenAIRE

    Ejby, Morten; Fredslund, Folmer; Vujicic-Zagar, Andreja; Svensson, Birte; Slotboom, Dirk Jan; Abou Hachem, Maher

    2013-01-01

    Glycan utilization plays a key role in modulating the composition of the gut microbiota, but molecular insight into oligosaccharide uptake by this microbial community is lacking. Arabinoxylo-oligosaccharides (AXOS) are abundant in the diet, and are selectively fermented by probiotic bifidobacteria in the colon. Here we show how selectivity for AXOS uptake is established by the probiotic strain Bifidobacterium animalis subsp. lactisBl-04. The binding protein BlAXBP, which is associated with an...

  7. Molecular cloning of the Golgi apparatus uridine diphosphate-N-acetylglucosamine transporter from Kluyveromyces lactis.

    OpenAIRE

    Abeijon, C; Robbins, P W; Hirschberg, C B

    1996-01-01

    The mannan chains of Kluyveromyces lactis mannoproteins are similar to those of Saccharomyces cerevisiae except that they lack mannose phosphate and have terminal alpha1-->2-linked N-acetylglucosamine. The biosynthesis of these chains probably occurs in the lumen of the Golgi apparatus, by analogy to S. cerevisiae. The sugar donors, GDP-mannose and UDP-GlcNAc, must first be transported from the cytosol, their site of synthesis, via specific Golgi membrane transporters into the lumen where the...

  8. Statistical investigation of Kluyveromyces lactis cells permeabilization with ethanol by response surface methodology

    OpenAIRE

    de Faria, Janaína T.; Rocha, Pollyana F.; Attilio Converti; Flávia M.L. Passos; Minim, Luis A.; Fábio C. Sampaio

    2014-01-01

    The aim of our study was to select the optimal operating conditions to permeabilize Kluyveromyces lactis cells using ethanol as a solvent as an alternative to cell disruption and extraction. Cell permeabilization was carried out by a non-mechanical method consisting of chemical treatment with ethanol, and the results were expressed as β-galactosidase activity. Experiments were conducted under different conditions of ethanol concentration, treatment time and temperature according to a central ...

  9. Genetic and Physiological Responses of Bifidobacterium animalis subsp. lactis to Hydrogen Peroxide Stress

    OpenAIRE

    Oberg, Taylor S.; Ward, Robert E.; Steele, James L.; Broadbent, Jeff R.

    2013-01-01

    Consumer interest in probiotic bifidobacteria is increasing, but industry efforts to secure high cell viability in foods is undermined by these anaerobes' sensitivity to oxidative stress. To address this limitation, we investigated genetic and physiological responses of two fully sequenced Bifidobacterium animalis subsp. lactis strains, BL-04 and DSM 10140, to hydrogen peroxide (H2O2) stress. Although the genome sequences for these strains are highly clonal, prior work showed that they differ...

  10. Characterization and Heterologous Expression of the Oxalyl Coenzyme A Decarboxylase Gene from Bifidobacterium lactis

    OpenAIRE

    Federici, Federica; Vitali, Beatrice; Gotti, Roberto; Pasca, Maria Rosalia; Gobbi, Silvia; Peck, Ammon B; Brigidi, Patrizia

    2004-01-01

    Oxalyl coenzyme A (CoA) decarboxylase (Oxc) is a key enzyme in the catabolism of the highly toxic compound oxalate, catalyzing the decarboxylation of oxalyl-CoA to formyl-CoA. The gene encoding a novel oxalyl-CoA decarboxylase from Bifidobacterium lactis DSM 10140 (oxc) was identified and characterized. This strain, isolated from yogurt, showed the highest oxalate-degrading activity in a preliminary screening with 12 strains belonging to Bifidobacterium, an anaerobic intestinal bacterial grou...

  11. Complete Genome Sequences of Probiotic Strains Bifidobacterium animalis subsp. lactis B420 and Bi-07

    OpenAIRE

    Stahl, Buffy; Barrangou, Rodolphe

    2012-01-01

    We present the complete genomes of Bifidobacterium animalis subsp. lactis B420 and Bi-07. Comparative genomic analysis with the type strain DSMZ10140 revealed 40 to 55 single nucleotide polymorphisms (SNPs) and an indel in a clustered regularly interspaced short palindromic repeat (CRISPR) locus. These genetic differences provide a molecular basis for strain typing within the two main phylogenetic groups of this monomorphic species.

  12. Transcriptional analysis of oligosaccharide utilization by Bifidobacterium lactis Bl-04

    OpenAIRE

    Andersen, Joakim Mark; Barrangou, Rodolphe; Abou Hachem, Maher; Lahtinen, Sampo J.; Goh, Yong Jun; Svensson, Birte; Klaenhammer, Todd R.

    2013-01-01

    BACKGROUND: Probiotic bifidobacteria in combination with prebiotic carbohydrates have documented positive effects on human health regarding gastrointestinal disorders and improved immunity, however the selective routes of uptake remain unknown for most candidate prebiotics. The differential transcriptomes of Bifidobacterium animalis subsp. lactis Bl-04, induced by 11 potential prebiotic oligosaccharides were analyzed to identify the genetic loci involved in the uptake and catabolism of α- and...

  13. IDENTIFICATION OF THE BACTERIUM TOMATO STEM CANKER

    Directory of Open Access Journals (Sweden)

    Goner A. Shaker

    2014-01-01

    Full Text Available Diseased tomato samples were collected from green house was evaluated for isolation, pathogenicity and biochemical tests. The symptoms of the infected tomato plants were as sudden wilting after curled on leaves and necrotic streak regions developed at the crown and base of the stem and the cavities deepen and expand up and down, brown discoloration and necrosis occurring on xylem and phloem vasculer. All of ages of tomato plant were susceptible to bacteria when the weather condition favorable and immediately, seen collapse symptom on tomato plant at once fail and die. The bacterium was isolated from diseased plant in all regions on nutrient Agar; a yellow bacterium was isolated from infected tomato plant in green houses and fields in Abu-Ghraib, Rashiedia and Qanat Al-Geiaysh nurseries in Baghdad provinces of Iraq. The bacterium was found gram positive, rod-shaped, non-motile and capable an aerobic growth and based on the morphological and biochemical characteristics revealed that this bacterium belongs to: Clavibacter michiganensis subsp. michiganensis. (smith pathogenicity and hypersensitivity of the bacterium Cmm showed the disease index were 18.33, 6.66, 16.66, 5, 0% for tomato seedlings were inoculated treatments as the wounding roots, without wounding roots, crown of the stem, petiole and control respectively.

  14. BIOLOG MICROLOG® IDENTIFICATION OF Lactococcus garvieae INFECTION IN NILE TILAPIA Oreochromis niloticus AND PINTADO Pseudoplathystoma corruscans FROM BRAZIL

    Science.gov (United States)

    Lactococcus garvieae infection in cultured Nile tilapia, Oreochromis niloticus, and pintado, Pseudoplathystoma corruscans from Brazil is reported. This is the first evidence of the presence of this pathogen from Brazilian fish and the first report of L. garvieae infection in either Nile tilapia or ...

  15. Microflora of urogenital tract in pregnancy with asymptomatic bacterium

    International Nuclear Information System (INIS)

    The article contains results of research interrelationship from colonization of vagina and urinary tract diseases. E.coli one of the main factors in development asymptomatic bacterium. Presented high effects of penicillin medicaments and nitrofurans in treatment of asymptomatic bacterium

  16. The GDI1 genes from Kluyveromyces lactis and Pichia pastoris: cloning and functional expression in Saccharomyces cerevisiae.

    Science.gov (United States)

    Brummer, M H; Richard, P; Sundqvist, L; Väänänen, R; Keränen, S

    2001-07-01

    The nucleotide sequences of 2.8 kb and 2.9 kb fragments containing the Kluyveromyces lactis and Pichia pastoris GDI1 genes, respectively, were determined. K. lactis GDI1 was found during sequencing of a genomic library clone, whereas the P. pastoris GDI1 was obtained from a genomic library by complementing a Saccharomyces cerevisiae sec19-1 mutant strain. The sequenced DNA fragments contain open reading frames of 1338 bp (K.lactis) and 1344 bp (P. pastoris), coding for polypeptides of 445 and 447 residues, respectively. Both sequences fully complement the S. cerevisiae sec19-1 mutation. They have high degrees of homology with known GDP dissociation inhibitors from yeast species and other eukaryotes. PMID:11447595

  17. INHIBITION OF STAPHYLOCOCCUS AUREUS BY LACTIC ACID BACTERIA AND / OR BIFIDOBACTERIUM LACTIS DURING MILK FERMENTATION AND STORAGE

    Directory of Open Access Journals (Sweden)

    Khalaf S. Al-Delaimy

    2013-02-01

    Full Text Available Survival and inhibition of Staphylococcus aureus by the lactic acid bacteria (LAB starter culture (Sterptococcus thermophillus and Lactobacillus delbrukii subsp. bulgaricus and/ or probiotic bacteria Bifidobacterium lactis during milk fermentation to yoghurt and storage up to 12 days was studied. Adding S. aureus (initial count log 6.64/ ml with LAB (initial count log 6.8/ ml in milk during yoghurt processing and storage resulted in no significant change in the counts of both S. aureus and LAB during fermentation period of 4 hrs at 45° C. A steady decrease in S. aureus count during storage at 25° C and 4° C was observed reaching a complete (100 % inhibition after 9 and 12 days, respectively, with no significant increase in LAB count. Adding S. aureus (initial count log 6.62/ ml with B. lactis (initial count log 6.83/ ml in milk for 4 hr at45° C, no significant changes in the counts of both bacteria were found. After storage at 25° C and at 4° C a sharp decline in the S. aureus count with a 100 % inhibition after 6 and 9 days with approximately two log and one log increase in B. lactis counts consecutively. In general similar result was observed when adding S. aureus together with LAB and B. lactis in milk during fermentation and storage. pH values decreased during milk fermentation and storage from initially 6.55-6.64 to around 4 in most milk samples. The results of this study show that S. aureus was completely inhibited by LAB and/or B. lactis after milk fermentation to yoghurt and storage at room temperature and refrigeration for 6-9 days. It is therefore recommended to add the probiotic B. lactis with LAB to milk for yoghurt processing.

  18. Analysis of the human intestinal epithelial cell transcriptional response to Lactobacillus acidophilus, Lactobacillus salivarius, Bifidobacterium lactis and Escherichia coli

    DEFF Research Database (Denmark)

    Putaala, H; Barrangou, R; Leyer, G J;

    2010-01-01

    comparative analysis of the global in vitro transcriptional response of human intestinal epithelial cells to Lactobacillus acidophilus NCFM™, Lactobacillus salivarius Ls-33, Bifidobacterium animalis subsp. lactis 420, and enterohaemorrhagic Escherichia coli O157:H7 (EHEC). Interestingly, L. salivarius Ls-33...... regulation of apoptosis and adipogenesis, and lipid-metabolism related regulation by the probiotics. Specific changes such as regulation of cell-cell adhesion by B. lactis 420, superoxide metabolism by L. salivarius Ls-33, and regulation of MAPK pathway by L. acidophilus NCFM™ were noted. Furthermore...

  19. KlROM2 encodes an essential GEF homologue in Kluyveromyces lactis.

    Science.gov (United States)

    Lorberg, Anja; Schmitz, Hans-Peter; Gengenbacher, Ute; Heinisch, Jürgen J

    2003-05-01

    Cellular integrity in yeasts is ensured by a rigid cell wall whose synthesis is controlled by a MAP kinase signal transduction cascade. In Saccharomyces cerevisiae upstream regulatory components of this MAP kinase pathway involve a single protein kinase C, which is regulated in part by interaction with the small GTPase Rho1p. This small G protein is in turn rendered inactive (GDP-bound) or is activated (GTP-bound) by the influence of GTPase activating proteins (GAPs) and the GDP/GTP exchange factors (GEFs), respectively. We report here on the isolation of a gene from Kluyveromyces lactis, KlROM2, which encodes a member of the latter protein family. The nucleotide sequence contains an open reading frame of 1227 amino acids, with an overall identity of 57% to the Rom2 protein of S. cerevisiae. Four conserved sequence motifs could be identified: a RhoGEF domain, a DEP sequence, a CNH domain and a less conserved pleckstrin homology (PH) sequence. Klrom2 null mutants show a lethal phenotype, which indicates that the gene may encode the only functional GEF regulating the cellular integrity pathway in K. lactis. Conditional genomic expression of KlROM2 resulted in sensitivity towards caffeine and Calcofluor white as typical phenotypes of mutants defective in this pathway. Overexpression of KIROM2 from multicopy plasmids under the control of the ScGAL1 promoter severely impaired growth in both S. cerevisiae and in K. lactis. The fact that the lethal phenotype was not prevented in mpk1 deletion mutants indicates that growth inhibition is not simply caused by hyperactivation of the Pkc1p signal transduction pathway. PMID:12734799

  20. Mutations Affecting Synthesis of β-Galactosidase Activity in the Yeast KLUYVEROMYCES LACTIS

    OpenAIRE

    Sheetz, R. Michael; Dickson, Robert C.

    1980-01-01

    Fifty-one mutants of Kluyveromyces lactis that cannot grow on lactose (Lac-) were isolated and characterized. All of the mutations are in nuclear genes, are recessive in their wild-type allele and define seven complementation groups, which we designate lac3 through lac9. Strains bearing mutations in lac3, lac5, lac7, lac8 and lac9 are also unable to grow on galactose (Gal-). Since the Gal- and Lac- phenotype co-segregate, they are probably due to a single mutation. Strains bearing mutations i...

  1. Estudo da viabilidade de Bifidobacterium animalis ssp. lactis em suco de Yacon

    OpenAIRE

    Watanabe, Felipe Miguel Farion

    2013-01-01

    Resumo: A maioria dos produtos probióticos são elaborados à base de leite, com desvantagens aos consumidores intolerantes à lactose, tornando assim produtos probióticos não lácteos vantajosos. O yacon é uma planta que acumula em suas raízes compostos prebióticos conhecidos como frutooligossacarídeos. O objetivo deste trabalho foi produzir o suco de yacon e utilizá-lo como matriz não láctea para a bactéria probiótica Bifidobacterium animalis ssp. lactis. O yacon apresentou rápido escurecimento...

  2. Prebiotic Effects of Agave salmiana Fructans in Lactobacillus acidophilus and Bifidobacterium lactis Cultures.

    Science.gov (United States)

    Castro-Zavala, Adriana; Juárez-Flores, Bertha I; Pinos-Rodríguez, Juan M; Delgado-Portales, Rosa E; Aguirre-Rivera, Juan R; Alcocer-Gouyonnet, Francisco

    2015-11-01

    Agave salmiana is a fructan rich species that is widely distributed in Mexico. The aim of this investigation was to extract the fructans of A. salmiana and evaluate their prebiotic effect in 48 hours in vitro cultures of Bifidobacterium lactis and Lactobacillus acidophilus and to compare this effect with other available fructan sources. A significant difference in pH, optical density and biomass was found in the cultures depending on the source of fructans and the type of bacteria. It was possible to determine a dose-response effect of the A. salmiana fructans and the growth of the studied strains. PMID:26749843

  3. Sphingobacterium psychroaquaticum sp. nov., a psychrophilic bacterium isolated from Lake Michigan water.

    Science.gov (United States)

    Albert, Richard A; Waas, Nancy E; Pavlons, Shawn C; Pearson, Jamie L; Ketelboeter, Laura; Rosselló-Móra, Ramon; Busse, Hans-Jürgen

    2013-03-01

    A psychrophilic, Gram-negative bacterium, designated MOL-1(T), was isolated from water of Lake Michigan. 16S rRNA gene sequence analysis revealed that the sequence of strain MOL-1(T) has sequence similarity of 95.6, 94.8, 94.3, 94.3, 94.2 and 93.9 %, respectively, to the 16S rRNA gene sequences of Sphingobacterium shayense HS39(T), S. lactis WCC 4512(T), S. composti T5-12(T), S. daejeonense TR6-04(T), S. bambusae IBFC2009(T) and S. alimentarium WCC 4521(T). The major cellular fatty acids were iso-C15 : 0, iso-C17 : 0 3-OH and summed feature 3 (iso-C15 : 0 2-OH and/or C16 : 1ω7c). Menaquinone MK-7 is the predominant respiratory quinone, while sym-homospermidine is the predominant polyamine. The polar lipid profile is composed of the predominant lipids phosphatidylethanolamine and unidentified polar lipid L2, with moderate amounts of unidentified polar lipids L1, L5 and L6 and unidentified aminophospholipids APL1 and APL2 and minor to trace amounts of unidentified polar lipids L3, L4, L7, L8, L9 and L10, unidentified phospholipid PL4 and unidentified aminophospholipid APL3. After molecular and phenotypic studies, including chemotaxonomic analyses, it was concluded that strain MOL-1(T) represents a novel Sphingobacterium species, for which the name Sphingobacterium psychroaquaticum sp. nov. is proposed. The type strain is MOL-1(T) ( = NRRL B-59232(T)  = DSM 22418(T)). PMID:22659507

  4. Isolation and characterization of exopolysaccharide from Leuconostoc lactis KC117496 isolated from idli batter.

    Science.gov (United States)

    Saravanan, Chinnashanmugam; Shetty, Prathap Kumar H

    2016-09-01

    Diverse exopolysaccharide (EPS)-producing isolates were isolated from an Indian acidic fermented food (Idli) based on the colony morphology. One of the EPS-producing microflora (Leuconostoc lactis KC117496) was selected for further characterization using FT-IR, HPTLC, AFM, SEM, TGA and XRD analysis. FT-IR spectroscopy revealed the α-d-glucose nature of the EPS. HPTLC analysis confirmed the presence of only glucose monomers, indicating the glucan nature of EPS. NMR spectra revealed the presence of 95% α-(1→6) and 5% branching α-(1→3) linkages. The SEM and AFM showed smooth surfaces and compact structure. TGA results showed higher degradation temperature of 272.01°C. XRD analysis proved the 33.4% crystalline nature of the EPS. Water solubility index and water-holding capacity of EPS are 14.2±0.208% and 117±7.5%. All the above characteristics of the EPS produced by L. lactis showed that the EPS is of a good-quality polysaccharide with potential applications in the food industry. PMID:25687478

  5. PEDIOCIN PRODUCTION IN MILK BY PEDIOCOCCUS ACIDILACTICI IN CO-CULTURE WITH STREPTOCOCCUS THERMOPHILUS AND LACTOBACILLUS DELBRUECKII SUBSP. BULGARICUS

    Science.gov (United States)

    The production of pediocin in milk by Pediococcus acidilactici was evaluated in co-culture with the dairy fermentation cultures Streptococcus thermophilus, Lactobacillus delbrueckii subsp. bulgaricus, and Lactococcus lactis subsp. lactis. The cultures were tested singly or in different combinations...

  6. Cytotoxicity of functionalized polystyrene latex nanoparticles toward lactic acid bacteria, and comparison with model microbes

    Energy Technology Data Exchange (ETDEWEB)

    Nomura, Toshiyuki, E-mail: nomura@chemeng.osakafu-u.ac.jp; Kuriyama, Yuta; Tokumoto, Hayato; Konishi, Yasuhiro [Osaka Prefecture University, Department of Chemical Engineering (Japan)

    2015-02-15

    The cytotoxicity and colloidal behavior of surface-functionalized polystyrene latex (PSL) nanoparticles (NPs) (nominal diameter: 100 nm) toward a model gram positive bacterium Lactococcus lactis JCM 5805 were examined. Nearly all the L. lactis cells exposed to the negatively charged PSL NPs survived because the surface of the bacterial cell was charged negatively, and the NPs therefore hardly adhere to the cell surface. In contrast, the positively charged PSL NPs adhered to the L. lactis cell surface but were not entrapped within the cell, and cell death subsequently occurred. The bacterial growth curves after the toxic NP exposure suggested that NP toxicity did not affect the specific growth phase, but did affect lag time. These results indicated that the cells were damaged by the cell disruption that resulted from the adhesion of the NPs to the cell surface. Finally, the cytotoxicity of the toxic, positively charged PSL NPs toward L. lactis was compared with that displayed toward a model gram negative bacterium Escherichia coli and a model eukaryote Saccharomyces cerevisiae. The cytotoxic behaviors of NPs on L. lactis and E. coli were similar, and depended not on the bacterial surface structure, but rather the environmental ionic strength. In contrast, the cytotoxicity of the prokaryote bacteria was higher than that toward the model eukaryote S. cerevisiae. The difference between the NP sensitivities of the prokaryote and eukaryote resulted from the prokaryote’s lack of an endocytotic pathway.

  7. Cytotoxicity of functionalized polystyrene latex nanoparticles toward lactic acid bacteria, and comparison with model microbes

    International Nuclear Information System (INIS)

    The cytotoxicity and colloidal behavior of surface-functionalized polystyrene latex (PSL) nanoparticles (NPs) (nominal diameter: 100 nm) toward a model gram positive bacterium Lactococcus lactis JCM 5805 were examined. Nearly all the L. lactis cells exposed to the negatively charged PSL NPs survived because the surface of the bacterial cell was charged negatively, and the NPs therefore hardly adhere to the cell surface. In contrast, the positively charged PSL NPs adhered to the L. lactis cell surface but were not entrapped within the cell, and cell death subsequently occurred. The bacterial growth curves after the toxic NP exposure suggested that NP toxicity did not affect the specific growth phase, but did affect lag time. These results indicated that the cells were damaged by the cell disruption that resulted from the adhesion of the NPs to the cell surface. Finally, the cytotoxicity of the toxic, positively charged PSL NPs toward L. lactis was compared with that displayed toward a model gram negative bacterium Escherichia coli and a model eukaryote Saccharomyces cerevisiae. The cytotoxic behaviors of NPs on L. lactis and E. coli were similar, and depended not on the bacterial surface structure, but rather the environmental ionic strength. In contrast, the cytotoxicity of the prokaryote bacteria was higher than that toward the model eukaryote S. cerevisiae. The difference between the NP sensitivities of the prokaryote and eukaryote resulted from the prokaryote’s lack of an endocytotic pathway

  8. Homologous expression and biochemical characterization of the arylsulfatase from Kluyveromyces lactis and its relevance in milk processing.

    Science.gov (United States)

    Stressler, Timo; Leisibach, Desirée; Lutz-Wahl, Sabine; Kuhn, Andreas; Fischer, Lutz

    2016-06-01

    The industrial manufacturing process of lactose-free milk products depends on the application of commercial β-galactosidase (lactase) preparations. These preparations are often obtained from Kluyveromyces lactis. There is a gene present in the genome of K. lactis which should encode for an enzyme called arylsulfatase (EC 3.1.6.1). Therefore, this enzyme could also be present in β-galactosidase preparations. The arylsulfatase is suspected of being responsible for an unpleasant "cowshed-like" off-flavor resulting from the release of p-cresol from milk endogenous alkylphenol sulfuric esters. So far, no gene/functionality relationship is described. In addition, no study is available which has shown that arylsulfatase from K. lactis is truly responsible for the flavor generation. In this study, we cloned the putative arylsulfatase gene from K. lactis GG799 into the commercially available vector pKLAC2. The cloning strategy chosen resulted in a homologous, secretory expression of the arylsulfatase. We showed that the heretofore putative arylsulfatase has the desired activity with the synthetic substrate p-nitrophenyl sulfate and with the natural substrate p-cresol sulfate. The enzyme was biochemically characterized and showed an optimum temperature of 45-50 °C and an optimum pH of 9-10. Additionally, the arylsulfatase was activated by Ca(2+) ions and was inactivated by Zn(2+) ions. Moreover, the arylsulfatase was inhibited by p-cresol and sulfate ions. Finally, the enzyme was added to ultra-heat treated (UHT) milk and a sensory triangle test verified that the arylsulfatase from K. lactis can cause an unpleasant "cowshed-like" off-flavor. PMID:26875879

  9. Towards in vivo regulon kinetics: PurR activation by 5-phosphoribosyl-a-1-pyrophosphate during purine depletion in Lactococcus lactis

    DEFF Research Database (Denmark)

    Jendresen, Christian Bille; Dimitrov, Peter; Gautier, Laurent;

    2014-01-01

    5-phosphoribosyl-a-1-pyrophosphate (PRPP) and individual mRNA levels, whereby unambiguous and homogeneous relations could be obtained for PurR regulated genes, thus linking a specific regulon to a specific metabolite. As PurR activates gene expression upon binding of PRPP, the pur mRNA curves...... reflect the in vivo kinetics of PurR PRPP binding and activation. The method singled out the xpt-pbuX operon as kinetically distinct, which was found to be caused by a guanine riboswitch whose regulation was overlaying the PurR regulation. Importantly, genes could be clustered according to regulatory...

  10. Isolation of a Bacterium Strain Degraded Agar

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    One in 58 strains of bacteria isolated from the compost showed clear colonies after a few days of growth on the plates containing medium made of only agar and water.Water suspension contained only agar (2 and 8g·L -1 ) with two controls (normal saline,LB medium) was inoculated with the bacterium BR5-1 to see whether there was an increasement of the alive bacteria concentration after 48 h of the growth.The results showed that there was a significant rising of the alive bacteria concentration in the agar susp...

  11. Induction and characterization of a lysogenic bacteriophage of Lactococcus garvieae isolated from marine fish species.

    Science.gov (United States)

    Hoai, T D; Yoshida, T

    2016-07-01

    This study investigated the presence of prophages in Lactococcus garvieae isolated from several marine fish species in Japan. Representative strains of 16 bacterial genotypes (S1-S16) selected from more than 400 L. garvieae isolates were used to induce lysogenic bacteriophages. These strains were treated with 500 ng mL(-1) freshly prepared mitomycin C. A cross-spotting assay was performed to validate the lysogenic and indicator strains. The lysogenic strains were selected for isolation and concentration of the phages. Phage DNA was digested with EcoRI for biased sinusoidal field gel electrophoresis analysis. Polymerase chain reaction (PCR) was used to detect integrated prophage DNA. Of the 16 representative bacterial genotypes, 12 strains integrated prophages as indicated by the PCR assay, and 10 phages were detected and isolated using two indicator bacterial strains. Analysis of genomic DNA showed that these phages were homologous and named as PLgT-1. Transmission electron microscopy revealed that the morphology of PLgT-1 was consistent with the virus family Siphoviridae. PCR analysis of the prophage DNA revealed that all of the S1 genotype strains were lysogenic (30/30), but none of the S16 genotype strains were lysogenic (0/30). This is the first study to investigate lysogenic bacteriophages from L. garvieae. PMID:26471724

  12. Growth kinetics and physiological behavior of co-cultures of Saccharomyces cerevisiae and Kluyveromyces lactis, fermenting carob sugars extracted with whey.

    Science.gov (United States)

    Rodrigues, B; Lima-Costa, M E; Constantino, A; Raposo, S; Felizardo, C; Gonçalves, D; Fernandes, T; Dionísio, L; Peinado, J M

    2016-10-01

    Alcoholic fermentation of carob waste sugars (sucrose, glucose and fructose) extracted with cheese whey, by co-cultures of Saccharomyces cerevisiae and Kluyveromyces lactis has been analyzed. Growth and fermentation of S. cerevisiae in the carob-whey medium showed an inhibition of about 30% in comparison with water-extracted carob. The inhibition of K. lactis on carob-whey was greater (70%) when compared with the whey medium alone, due to osmolarity problems. Oxygen availability was a very important factor for K. lactis, influencing its fermentation performance. When K. lactis was grown alone on carob-whey medium, lactose was always consumed first, and glucose and fructose were consumed afterwards, only at high aeration conditions. In co-culture with S. cerevisiae, K. lactis was completely inhibited and, at low aeration, died after 3 days; at high aeration this culture could survive but growth and lactose fermentation were only recovered after S. cerevisiae became stationary. To overcome the osmolarity and K. lactis' oxygen problems, the medium had to be diluted and a sequential fermentative process was designed in a STR-3l reactor. K. lactis was inoculated first and, with low aeration (0.13vvm), consumed all the lactose in 48h. Then S. cerevisiae was inoculated, consuming the total of the carob sugars, and producing ethanol in a fed-batch regime. The established co-culture with K. lactis increased S. cerevisiae ethanol tolerance. This fermentation process produced ethanol with good efficiency (80g/l final concentration and a conversion factor of 0.4g ethanol/g sugar), eliminating all the sugars of the mixed waste. These efficient fermentative results pointed to a new joint treatment of agro-industrial wastes which may be implemented successfully, with economic and environmental sustainability for a bioethanol industrial proposal. PMID:27542743

  13. Inhibitory effect of honey-sweetened goat and cow milk fermented with Bifidobacterium lactis Bb-12 on the growth of Listeria monocytogenes

    OpenAIRE

    Mirela Lučan; Vedran Slačanac; Jovica Hardi; Krešimir Mastanjević; Jurislav Babić; Vinko Krstanović; Marko Jukić

    2009-01-01

    The aim of the study was to determine the influence of honey addition on fermentation of goat and cow milk with Bifidobacterium lactis Bb-12. Additionally, inhibitory potential of honey-sweetened fermented goat and cow milk against Listeria monocytogenes strain was examined. Two monofloral honey types, dark-colored chestnut and light-colored acacia honey were added. The basic hypothesis of this study was that addition of honey could have influence on the growth of Bifidobacterium lactis durin...

  14. Biodegradation of heavy oils by halophilic bacterium

    Institute of Scientific and Technical Information of China (English)

    Ruixia Hao; Anhuai Lu

    2009-01-01

    A halophilic bacterial strain TM-1 was isolated from the reservoir of the Shengli oil field in East China. Strain TM-1, which was found to be able to degrade crude oils, is a gram-positive non-motile bacterium with a coccus shape that can grow at temperatures of up to 58 ℃ and in 18% NaCl solution. Depending on the culture conditions, the organism may occur in tetrads. In addition, strain TM-1 pro-duced acid from glucose without gas formation and was catalase-negative. Furthermore, strain TM-I was found to be a facultative aer-obe capable of growth under anaerobic conditions. Moreover, it produced butylated hydroxytoluene, 1,2-benzenedicarboxylic acid-bis ester and dibutyl phthalate and could use different organic substrates. Laboratory studies indicated that strain TM-1 affected different heavy oils by degrading various components and by changing the chemical properties of the oils. In addition, growth of the bacterium in heavy oils resulted in the loss of aromatic hydrocarbons, resins and asphaltenes, and enrichment with light hydrocarbons and an overall redistribution of these hydrocarbons.

  15. Insights into physiological traits of Bifidobacterium animalis subsp. lactis BB-12 through membrane proteome analysis

    DEFF Research Database (Denmark)

    Gilad, Ofir; Hjernø, Karin; Østerlund, Eva Christina;

    2012-01-01

    Bifidobacterium animalis subsp. lactis BB-12 is a widely used probiotic strain associated with a variety of health-promoting traits. There is, however, only limited knowledge available regarding the membrane proteome and the proteins involved in oligosaccharide transport in BB-12. We applied two...... enrichment strategies to improve the identification of membrane proteins from BB-12 cultures grown on glucose and on xylo-oligosaccharides, the latter being an emerging prebiotic substrate recently reported to be fermented by BB-12. Our approach encompassed consecutive steps of detergent- and carbonate......-treatment in order to generate inside-out membrane vesicles and to interfere with binding of membrane-associated proteins to the membrane, respectively. Proteins in the enriched membrane fraction and membrane-associated fraction were digested by lysyl endopeptidase and trypsin followed by peptide sequencing by...

  16. Structural basis for arabinoxylo‐oligosaccharide capture by the probiotic Bifidobacterium animalis subsp. lactis Bl‐04

    DEFF Research Database (Denmark)

    Hansen, Morten Ejby; Fredslund, Folmer; Vujicic‐Zagar, Andreja;

    2013-01-01

    Glycan utilization plays a key role in modulating the composition of the gut microbiota, but molecular insight into oligosaccharide uptake by this microbial community is lacking. Arabinoxylo‐oligosaccharides (AXOS) are abundant in the diet, and are selectively fermented by probiotic bifidobacteria...... in the colon. Here we show how selectivity for AXOS uptake is established by the probiotic strain Bifidobacterium animalis subsp. lactis Bl‐04. The binding protein BlAXBP, which is associated with an ATP‐binding cassette (ABC) transporter that mediates the uptake of AXOS, displays an exceptionally...... broad specificity for arabinosyl‐decorated and undecorated xylo‐oligosaccharides, with preference for tri‐ and tetra‐saccharides. Crystal structures of BlAXBP in complex with four different ligands revealed the basis for this versatility. Uniquely, the protein was able to recognize oligosaccharides in...

  17. How recombinant swollenin from Kluyveromyces lactis affects cellulosic substrates and accelerates their hydrolysis

    Directory of Open Access Journals (Sweden)

    Jäger Gernot

    2011-09-01

    Full Text Available Abstract Background In order to generate biofuels, insoluble cellulosic substrates are pretreated and subsequently hydrolyzed with cellulases. One way to pretreat cellulose in a safe and environmentally friendly manner is to apply, under mild conditions, non-hydrolyzing proteins such as swollenin - naturally produced in low yields by the fungus Trichoderma reesei. To yield sufficient swollenin for industrial applications, the first aim of this study is to present a new way of producing recombinant swollenin. The main objective is to show how swollenin quantitatively affects relevant physical properties of cellulosic substrates and how it affects subsequent hydrolysis. Results After expression in the yeast Kluyveromyces lactis, the resulting swollenin was purified. The adsorption parameters of the recombinant swollenin onto cellulose were quantified for the first time and were comparable to those of individual cellulases from T. reesei. Four different insoluble cellulosic substrates were then pretreated with swollenin. At first, it could be qualitatively shown by macroscopic evaluation and microscopy that swollenin caused deagglomeration of bigger cellulose agglomerates as well as dispersion of cellulose microfibrils (amorphogenesis. Afterwards, the effects of swollenin on cellulose particle size, maximum cellulase adsorption and cellulose crystallinity were quantified. The pretreatment with swollenin resulted in a significant decrease in particle size of the cellulosic substrates as well as in their crystallinity, thereby substantially increasing maximum cellulase adsorption onto these substrates. Subsequently, the pretreated cellulosic substrates were hydrolyzed with cellulases. Here, pretreatment of cellulosic substrates with swollenin, even in non-saturating concentrations, significantly accelerated the hydrolysis. By correlating particle size and crystallinity of the cellulosic substrates with initial hydrolysis rates, it could be shown that

  18. Ratoon stunting disease of sugarcane: isolation of the causal bacterium.

    Science.gov (United States)

    Davis, M J; Gillaspie, A G; Harris, R W; Lawson, R H

    1980-12-19

    A small coryneform bacterium was consistently isolated from sugarcane with ratoon stunting disease and shown to be the causal agent. A similar bacterium was isolated from Bermuda grass. Both strains multiplied in sugarcane and Bermuda grass, but the Bermuda grass strain did not incite the symptoms of ratoon stunting disease in sugarcane. Shoot growth in Bermuda grass was retarded by both strains. PMID:17817853

  19. Selective enumeration and viability of Bifidobacterium animalis subsp. lactis in a new fermented milk product Enumeração seletiva e viabilidade de Bifidobacterium animalis subsp. lactis em um novo produto lácteo fermentado

    OpenAIRE

    Adriane Elisabete Costa Antunes; Elza Terezinha Grael; Izildinha Moreno; Luana Gajardoni Rodrigues; Fernanda Martelo Dourado; Daniela Marques Saccaro; Alda Luiza Santos Lerayer

    2007-01-01

    One of the key focuses of today's dairy industry worldwide is the continued development of new products, especially probiotic-based products. Buttermilk is originally a by-product of butter making fermented by Mesophilic Aromatic Cultures (MAC). It can also be made by fermentation of pasteurized whole milk or skimmed milk. This product is not marketed in Brazil. The objectives of this work were: (1) to develop a selective medium for Bifidobacterium animalis subsp. lactis enumeration and (2) t...

  20. Characterization of plasmids in a human clinical strain of Lactococcus garvieae.

    Directory of Open Access Journals (Sweden)

    Mónica Aguado-Urda

    Full Text Available The present work describes the molecular characterization of five circular plasmids found in the human clinical strain Lactococcus garvieae 21881. The plasmids were designated pGL1-pGL5, with molecular sizes of 4,536 bp, 4,572 bp, 12,948 bp, 14,006 bp and 68,798 bp, respectively. Based on detailed sequence analysis, some of these plasmids appear to be mosaics composed of DNA obtained by modular exchange between different species of lactic acid bacteria. Based on sequence data and the derived presence of certain genes and proteins, the plasmid pGL2 appears to replicate via a rolling-circle mechanism, while the other four plasmids appear to belong to the group of lactococcal theta-type replicons. The plasmids pGL1, pGL2 and pGL5 encode putative proteins related with bacteriocin synthesis and bacteriocin secretion and immunity. The plasmid pGL5 harbors genes (txn, orf5 and orf25 encoding proteins that could be considered putative virulence factors. The gene txn encodes a protein with an enzymatic domain corresponding to the family actin-ADP-ribosyltransferases toxins, which are known to play a key role in pathogenesis of a variety of bacterial pathogens. The genes orf5 and orf25 encode two putative surface proteins containing the cell wall-sorting motif LPXTG, with mucin-binding and collagen-binding protein domains, respectively. These proteins could be involved in the adherence of L. garvieae to mucus from the intestine, facilitating further interaction with intestinal epithelial cells and to collagenous tissues such as the collagen-rich heart valves. To our knowledge, this is the first report on the characterization of plasmids in a human clinical strain of this pathogen.

  1. A peptidome-based phylogeny pipeline reveals differential peptides at the strain level within Bifidobacterium animalis subsp. lactis.

    Science.gov (United States)

    Blanco-Míguez, Aitor; Gutiérrez-Jácome, Alberto; Fdez-Riverola, Florentino; Lourenço, Anália; Sánchez, Borja

    2016-12-01

    Bifidobacteria are gut commensal microorganisms belonging to the Actinobacteria group. Some specific strains of Bifidobacterium animalis subsp. lactis are used in functional foods as they are able to exert health-promoting effects in the human host. Due to the limited genetic variability within this subspecies, it is sometimes difficult for a manufacturer to properly track its strain once included in dairy products or functional foods. In this paper, we present a peptidome-based analysis in which the proteomes of a set of B. animalis subsp. lactis strains were digested in silico with human gut endopeptidases. The molecular masses were compared along all the strains to detect strain-specific peptides. These peptides may be interesting towards the development of methodologies for strain identification in the final product. PMID:27554155

  2. Fluctuation-Enhanced Sensing of Bacterium Odors

    CERN Document Server

    Chang, Hung-Chih; King, Maria D; Kwan, Chiman

    2009-01-01

    The goal of this paper is to explore the possibility to detect and identify bacteria by sensing their odor via fluctuation-enhanced sensing with commercial Taguchi sensors. The fluctuations of the electrical resistance during exposure to different bacterial odors, Escherichia coli and anthrax-surrogate Bacillus subtilis, have been measured and analyzed. In the present study, the simplest method, the measurement and analysis of power density spectra was used. The sensors were run in the normal heated and the sampling-and-hold working modes, respectively. The results indicate that Taguchi sensors used in these fluctuation-enhanced modes are effective tools of bacterium detection and identification even when they are utilizing only the power density spectrum of the stochastic sensor signal.

  3. INHIBITION OF STAPHYLOCOCCUS AUREUS BY LACTIC ACID BACTERIA AND / OR BIFIDOBACTERIUM LACTIS DURING MILK FERMENTATION AND STORAGE

    OpenAIRE

    Khalaf S. Al-Delaimy; Yaser M. Hamamdeh

    2013-01-01

    Survival and inhibition of Staphylococcus aureus by the lactic acid bacteria (LAB) starter culture (Sterptococcus thermophillus and Lactobacillus delbrukii subsp. bulgaricus) and/ or probiotic bacteria Bifidobacterium lactis during milk fermentation to yoghurt and storage up to 12 days was studied. Adding S. aureus (initial count log 6.64/ ml) with LAB (initial count log 6.8/ ml) in milk during yoghurt processing and storage resulted in no significant change in the counts of both S. aureus an...

  4. Secretion and properties of a hybrid Kluyveromyces lactis-Aspergillus niger β-galactosidase

    OpenAIRE

    Becerra Manuel; Siso M Isabel; Cerdán M Esperanza; Trillo M Cristina; Leiro Rafael; Rodríguez Ángel

    2006-01-01

    Abstract Background The β-galactosidase from Kluyveromyces lactis is a protein of outstanding biotechnological interest in the food industry and milk whey reutilization. However, due to its intracellular nature, its industrial production is limited by the high cost associated to extraction and downstream processing. The yeast-system is an attractive method for producing many heterologous proteins. The addition of a secretory signal in the recombinant protein is the method of choice to sort it...

  5. Perdeuteration and methyl-selective 1H, 13C-labeling by using a Kluyveromyces lactis expression system

    International Nuclear Information System (INIS)

    The production of stable isotope-labeled proteins is critical in structural analyses of large molecular weight proteins using NMR. Although prokaryotic expression systems using Escherichia coli have been widely used for this purpose, yeast strains have also been useful for the expression of functional eukaryotic proteins. Recently, we reported a cost-effective stable isotope-labeled protein expression using the hemiascomycete yeast Kluyveromyces lactis (K. lactis), which allow us to express exogenous proteins at costs comparable to prokaryotic expression systems. Here, we report the successful production of highly deuterated (>90 %) protein in the K. lactis system. We also examined the methyl-selective 1H, 13C-labeling of Ile, Leu, and Val residues using commonly used amino acid precursors. The efficiency of 1H- 13C-incorporation varied significantly based on the amino acid. Although a high level of 1H-13C-incorporation was observed for the Ile δ1 position, 1H, 13C-labeling rates of Val and Leu methyl groups were limited due to the mitochondrial localization of enzymes involved in amino acid biosynthesis and the lack of transporters for α-ketoisovalerate in the mitochondrial membrane. In line with this notion, the co-expression with branched-chain-amino-acid aminotransferase in the cytosol significantly improved the incorporation rates of amino acid precursors. Although it would be less cost-effective, addition of 13C-labeled valine can circumvent problems associated with precursors and achieve high level 1H, 13C-labeling of Val and Leu. Taken together, the K. lactis system would be a good alternative for expressing large eukaryotic proteins that need deuteration and/or the methyl-selective 1H, 13C-labeling for the sensitive detection of NMR resonances

  6. Perdeuteration and methyl-selective {sup 1}H, {sup 13}C-labeling by using a Kluyveromyces lactis expression system

    Energy Technology Data Exchange (ETDEWEB)

    Miyazawa-Onami, Mayumi [Japan Biological Informatics Consortium, Research and Development Department (Japan); Takeuchi, Koh [National Institute of Advanced Industrial Science and Technology, Biomedicinal Information Research Center (Japan); Takano, Toshiaki; Sugiki, Toshihiko [Japan Biological Informatics Consortium, Research and Development Department (Japan); Shimada, Ichio, E-mail: shimada@iw-nmr.f.u-tokyo.ac.jp; Takahashi, Hideo, E-mail: hid@tsurumi.yokohama-cu.ac.jp [National Institute of Advanced Industrial Science and Technology, Biomedicinal Information Research Center (Japan)

    2013-10-22

    The production of stable isotope-labeled proteins is critical in structural analyses of large molecular weight proteins using NMR. Although prokaryotic expression systems using Escherichia coli have been widely used for this purpose, yeast strains have also been useful for the expression of functional eukaryotic proteins. Recently, we reported a cost-effective stable isotope-labeled protein expression using the hemiascomycete yeast Kluyveromyces lactis (K. lactis), which allow us to express exogenous proteins at costs comparable to prokaryotic expression systems. Here, we report the successful production of highly deuterated (>90 %) protein in the K. lactis system. We also examined the methyl-selective {sup 1}H, {sup 13}C-labeling of Ile, Leu, and Val residues using commonly used amino acid precursors. The efficiency of {sup 1}H- {sup 13}C-incorporation varied significantly based on the amino acid. Although a high level of {sup 1}H-{sup 13}C-incorporation was observed for the Ile δ1 position, {sup 1}H, {sup 13}C-labeling rates of Val and Leu methyl groups were limited due to the mitochondrial localization of enzymes involved in amino acid biosynthesis and the lack of transporters for α-ketoisovalerate in the mitochondrial membrane. In line with this notion, the co-expression with branched-chain-amino-acid aminotransferase in the cytosol significantly improved the incorporation rates of amino acid precursors. Although it would be less cost-effective, addition of {sup 13}C-labeled valine can circumvent problems associated with precursors and achieve high level {sup 1}H, {sup 13}C-labeling of Val and Leu. Taken together, the K. lactis system would be a good alternative for expressing large eukaryotic proteins that need deuteration and/or the methyl-selective {sup 1}H, {sup 13}C-labeling for the sensitive detection of NMR resonances.

  7. Genetic and Physiological Responses of Bifidobacterium animalis subsp. lactis to Hydrogen Peroxide Stress

    OpenAIRE

    Oberg, T. S.; Ward, R. E.; Steele, J L; Broadbent, Jeffery R.

    2013-01-01

    Consumer interest in probiotic bifidobact eria is increasing, but industry efforts to secure high cell viability in foods is dermined by these anaerobes’ sensitivity to oxidative stress. To address this limitati on, we investigated genetic and physiological responses of two fully sequenced Bifidobacterium animalis subsp. lactis strains, BL-04 and DSM 10140, to hydrogen peroxide (H2O2) stress. Although the genome sequences for these strains are highly clonal, prior work showed they differ in b...

  8. Milk-derived angiotensin-I-converting enzymeinhibitory peptides generated by Lactobacillus delbrueckii subsp. lactis CRL 581

    Directory of Open Access Journals (Sweden)

    Villegas Josefina M.

    2014-01-01

    Full Text Available Several strains of Lactobacillus helveticus and Lactobacillus delbrueckii subsp. lactis were evaluated for their ability to release angiotensin-I-converting enzyme (ACE inhibitory peptides from α-casein (α-CN and β-casein (β-CN. Casein peptides resulting from L. delbrueckii subsp. lactis CRL 581-mediated hydrolysis exhibited the highest ACE-inhibitory (ACEI activities, with values of 53 and 40% for α-CN and β-CN, respectively. The casein hydrolysates were fractionated by reversedphase high pressure liquid chromatography and some of the active peptides were identified by mass spectrometry. The fraction with the highest ACEI activity arose from β-CN and contained a mixture of the β-CN f194-206 (QEPVLGPVRGPFP and f198-206 (LGPVRGPFP peptides. Furthermore, the ACEI tripeptide IPP was identified in all β-CN hydrolysates; L. delbrueckii subsp. lactis CRL 581 produced the highest amount of this peptide. The bioactive peptides released by CRL 581 strain may be used in the formulation of functional foods and nutraceuticals, representing a healthier and natural alternative for regulating blood pressure.

  9. Identification of the beta-glucosidase gene from Bifidobacterium animalis subsp. lactis and its expression in B. bifidum BGN4.

    Science.gov (United States)

    Youn, So Youn; Park, Myeong Soo; Ji, Geun Eog

    2012-12-01

    beta-Glucosidase is necessary for the bioconversion of glycosidic phytochemicals in food. Two Bifidobacterium strains (Bifidobacterium animalis subsp. lactis SH5 and B. animalis subsp. lactis RD68) with relatively high beta- glucosidase activities were selected among 46 lactic acid bacteria. A beta-glucosidase gene (bbg572) from B. lactis was shotgun cloned, fully sequenced, and analyzed for its transcription start site, structural gene, and deduced transcriptional terminator. The structural gene of bbg572 was 1,383 bp. Based on amino sequence similarities, bbg572 was assigned to family 1 of the glycosyl hydrolases. To overexpress bbg572 in Bifidobacterium, several bifidobacteria expression vectors were constructed by combining several promoters and a terminator sequence from different bifidobacteria. The maximum activity of recombinant Bbg572 was achieved when it was expressed under its own promoter and terminator. Its enzyme activity increased 31-fold compared with those of its parental strains. The optimal pH for Bbg572 was pH 6.0. Bbg572 was stable at 37-40 degrees C. It hydrolyzed isoflavones, quercetins, and disaccharides with various beta-glucoside linkages. Bbg572 also converted the ginsenosides Rb1 and Rb2. These results suggest that this new beta-glucosidase-positive Bifidobacterium transformant can be utilized for the production of specific aglycone products. PMID:23221535

  10. Carbohydrate metabolism and lactic acid biosynthesis of Lactococcus lactis subsp.lactis KLDS4.0325%乳酸乳球菌KLDS4.0325的糖代谢过程及乳酸生物合成途径的比较

    Institute of Scientific and Technical Information of China (English)

    杨晓春; 王玉堂; 周颖; 高晓峰; 李柏良; 霍贵成

    2014-01-01

    [目的]为了探究乳酸乳球菌乳酸亚种KLDS4.0325的碳水化合物利用能力和乳酸形成潜力.[方法]本文对该菌株进行了全基因组鸟枪法测序,并应用生物信息学方法对该菌株细胞外糖的转运、代谢及产酸途径涉及的一系列基因与其它9株参考菌株进行了比较分析.[结果]与参考菌株相比,该菌株基因组中具有较多涉及整个途径糖代谢途径的关键酶编码基因.[结论]该菌株在基因水平上表现出能够利用多种糖类物质来产乳酸的优良性状,是一株具有高产L-乳酸工业潜能的乳酸菌.

  11. Proteomic and functional consequences of hexokinase deficiency in glucose-repressible Kluyveromyces lactis.

    Science.gov (United States)

    Mates, Nadia; Kettner, Karina; Heidenreich, Falk; Pursche, Theresia; Migotti, Rebekka; Kahlert, Günther; Kuhlisch, Eberhard; Breunig, Karin D; Schellenberger, Wolfgang; Dittmar, Gunnar; Hoflack, Bernard; Kriegel, Thomas M

    2014-03-01

    The analysis of glucose signaling in the Crabtree-positive eukaryotic model organism Saccharomyces cerevisiae has disclosed a dual role of its hexokinase ScHxk2, which acts as a glycolytic enzyme and key signal transducer adapting central metabolism to glucose availability. In order to identify evolutionarily conserved characteristics of hexokinase structure and function, the cellular response of the Crabtree-negative yeast Kluyveromyces lactis to rag5 null mutation and concomitant deficiency of its unique hexokinase KlHxk1 was analyzed by means of difference gel electrophoresis. In total, 2,851 fluorescent spots containing different protein species were detected in the master gel representing all of the K. lactis proteins that were solubilized from glucose-grown KlHxk1 wild-type and mutant cells. Mass spectrometric peptide analysis identified 45 individual hexokinase-dependent proteins related to carbohydrate, short-chain fatty acid and tricarboxylic acid metabolism as well as to amino acid and protein turnover, but also to general stress response and chromatin remodeling, which occurred as a consequence of KlHxk1 deficiency at a minimum 3-fold enhanced or reduced level in the mutant proteome. In addition, three proteins exhibiting homology to 2-methylcitrate cycle enzymes of S. cerevisiae were detected at increased concentrations, suggesting a stimulation of pyruvate formation from amino acids and/or fatty acids. Experimental validation of the difference gel electrophoresis approach by post-lysis dimethyl labeling largely confirmed the abundance changes detected in the mutant proteome via the former method. Taking into consideration the high proportion of identified hexokinase-dependent proteins exhibiting increased proteomic levels, KlHxk1 is likely to have a repressive function in a multitude of metabolic pathways. The proteomic alterations detected in the mutant classify KlHxk1 as a multifunctional enzyme and support the view of evolutionary conservation of

  12. The influence of lactulose on growth and survival of probiotic bacteria Lactobacillus acidophilus La-5 and Bifidobacterium animalis subsp. lactis BB-12 in reconstituted sweet whey

    Directory of Open Access Journals (Sweden)

    Bojan Matijević

    2009-03-01

    Full Text Available This research was examined the influence of lactulose, a well-defined prebiotic, on the growth and activity of probiotic bacteria Lactobacillus acidophilus La-5 and Bifidobacterium animalis subsp. lactis BB-12 in reconstituted sweet whey as well as their survival in fermented whey during 28 days of cool storage. Reconstituted sweet whey was supplemented with 5 and 10 g/kg lactulose. Fermentation of whey with Bifidobacterium animalis subsp. lactis BB-12 was about 1.8 h shorter (approximately 11 h in comparison to fermentation with Lactobacillus acidophilus La-5 (approximately 13 h. Lactulose addition in reconstituted sweet whey prolonged the time of fermentation in both bacteria species, but it did not influence on the viable cells count at the end of fermentation. Lactobacillus acidophilus La-5 better grew (Δlog CFU/ml = 1.25 during fermentation in comparison with Bifidobacterium animalis subsp. lactis BB-12 (Δlog CFU/ml = 0.27, regardless to the added amount of lactulose. During storage of fermented whey viable cells count of species Bifidobacterium animalis subsp. lactis BB-12 was more stable than count of Lactobacillus acidophilus La-5. The obtained results show that lactulose, as a well-defined prebiotic did not have a significant effect on fermentation and survival of Lactobacillus acidophilus La-5 and Bifidobacterium animalis subsp. lactis BB-12 in whey, regardless to the added amount.

  13. Genome Sequence of the Soil Bacterium Janthinobacterium sp. KBS0711

    OpenAIRE

    Shoemaker, William R.; Muscarella, Mario E.; Lennon, Jay T

    2015-01-01

    We present a draft genome of Janthinobacterium sp. KBS0711 that was isolated from agricultural soil. The genome provides insight into the ecological strategies of this bacterium in free-living and host-associated environments.

  14. Production of orotic acid by a Klura3Δ mutant of Kluyveromyces lactis.

    Science.gov (United States)

    Carvalho, Nuno; Coelho, Eduardo; Gales, Luís; Costa, Vítor; Teixeira, José António; Moradas-Ferreira, Pedro

    2016-06-01

    We demonstrated that a Klura3Δ, mutant of the yeast Kluyveromyces lactis is able to produce and secrete into the growth medium considerable amounts of orotic acid. Using yeast extract-peptone-glucose (YPD) based media we optimized production conditions in flask and bioreactor cultures. With cells grown in YPD 5% glucose medium, the best production in flask was obtained with a 1:12.5 ratio for flask: culture volume, 180 rpm, 28°C and 200 mM MOPS for pH stabilization at neutral values (initial culture pH at 8.0). The best production in a 2 L bioreactor was achieved at 500 rpm with 1 vvm aeration, 28°C and pH 7.0. Under these optimum conditions, similar rates of orotic acid production were obtained and maximum concentration achieved after 96 h was 6.7 g/L in flask and bioreactor cultures. These results revealed an excellent reproducibility between both systems and provided evidence for the biotechnological potential of Klura3Δ strain to produce orotic acid since the amounts obtained are comparable to the production in flask using a similar mutant of the industrially valuable Corynebacterium glutamicum. PMID:26707627

  15. Trichloroethylene Biodegradation by a Methane-Oxidizing Bacterium

    OpenAIRE

    Little, C. Deane; Palumbo, Anthony V; Herbes, Stephen E.; Lidstrom, Mary E.; Tyndall, Richard L.; Gilmer, Penny J.

    1988-01-01

    Trichloroethylene (TCE), a common groundwater contaminant, is a suspected carcinogen that is highly resistant to aerobic biodegradation. An aerobic, methane-oxidizing bacterium was isolated that degrades TCE in pure culture at concentrations commonly observed in contaminated groundwater. Strain 46-1, a type I methanotrophic bacterium, degraded TCE if grown on methane or methanol, producing CO2 and water-soluble products. Gas chromatography and 14C radiotracer techniques were used to determine...

  16. Taxonomic characterization of the cellulose-degrading bacterium NCIB 10462

    Energy Technology Data Exchange (ETDEWEB)

    Dees, C.; Ringleberg, D.; Scott, T.C. [Oak Ridge National Lab., TN (United States); Phelps, T. [Univ. of Tennessee, Knoxville, TN (United States)

    1994-06-01

    The gram negative cellulase-producing bacterium NCIB 10462 has been previously named Pseudomonas fluorescens subsp. or var. cellulosa. Since there is renewed interest in cellulose-degrading bacteria for use in bioconversion of cellulose to chemical feed stocks and fuels, we re-examined the characteristics of this microorganism to determine its proper taxonomic characterization and to further define it`s true metabolic potential. Metabolic and physical characterization of NCIB 10462 revealed that this was an alkalophilic, non-fermentative, gram negative, oxidase positive, motile, cellulose-degrading bacterium. The aerobic substrate utilization profile of this bacterium was found to have few characteristics consistent with a classification of P. fluorescens with a very low probability match with the genus Sphingomonas. Total lipid analysis did not reveal that any sphingolipid bases are produced by this bacterium. NCIB 10462 was found to grow best aerobically but also grows well in complex media under reducing conditions. NCIB 10462 grew slowly under full anaerobic conditions on complex media but growth on cellulosic media was found only under aerobic conditions. Total fatty acid analysis (MIDI) of NCIB 10462 failed to group this bacterium with a known pseudomonas species. However, fatty acid analysis of the bacteria when grown at temperatures below 37{degrees}C suggest that the organism is a pseudomonad. Since a predominant characteristic of this bacterium is it`s ability to degrade cellulose, we suggest it be called Pseudomonas cellulosa.

  17. A Sequential Statistical Approach towards an Optimized Production of a Broad Spectrum Bacteriocin Substance from a Soil Bacterium Bacillus sp. YAS 1 Strain

    Directory of Open Access Journals (Sweden)

    Amira M. Embaby

    2014-01-01

    Full Text Available Bacteriocins, ribosomally synthesized antimicrobial peptides, display potential applications in agriculture, medicine, and industry. The present study highlights integral statistical optimization and partial characterization of a bacteriocin substance from a soil bacterium taxonomically affiliated as Bacillus sp. YAS 1 after biochemical and molecular identifications. A sequential statistical approach (Plackett-Burman and Box-Behnken was employed to optimize bacteriocin (BAC YAS 1 production. Using optimal levels of three key determinants (yeast extract (0.48% (w/v, incubation time (62 hrs, and agitation speed (207 rpm in peptone yeast beef based production medium resulted in 1.6-fold enhancement in BAC YAS 1 level (470 AU/mL arbitrary units against Erwinia amylovora. BAC YAS 1 showed activity over a wide range of pH (1–13 and temperature (45–80°C. A wide spectrum antimicrobial activity of BAC YAS 1 against the human pathogens (Clostridium perfringens, Staphylococcus epidermidis, Campylobacter jejuni, Enterobacter aerogenes, Enterococcus sp., Proteus sp., Klebsiella sp., and Salmonella typhimurium, the plant pathogen (E. amylovora, and the food spoiler (Listeria innocua was demonstrated. On top and above, BAC YAS 1 showed no antimicrobial activity towards lactic acid bacteria (Lactobacillus bulgaricus, L. casei, L. lactis, and L. reuteri. Promising characteristics of BAC YAS 1 prompt its commercialization for efficient utilization in several industries.

  18. Fermentación in vitro de nopal forrajero con un inóculo de levadura Kluyveromyces lactis obtenida a partir de manzana de desecho

    Directory of Open Access Journals (Sweden)

    S. Mena-Mungía

    2012-01-01

    Full Text Available ResumenEl objetivo del presente estudio fue evaluar el efecto de un inóculo de levadura Kluyveromyces lactis, obtenida a partir de manzana de desecho de la variedad Golden Delicious en la fermentación en estado sólido (FES de nopalforrajero Opuntia spp.SummaryThe aim of this study was to evaluate the effect of an inoculum of yeast Kluyveromyces lactis, from apple waste on the variety Golden Delicious in solid state fermentation (SSF of forage prickly pear cactus Opuntia spp.

  19. Fermentación in vitro de nopal forrajero con un inóculo de levadura Kluyveromyces lactis obtenida a partir de manzana de desecho

    OpenAIRE

    S. Mena-Mungía; D. Díaz-Plascencia; C. Rodríguez-Muela; P. Mancillas-Flores; N. Ruíz-Holguín; F. Salvador-Torres; L. Duran-Meléndez

    2012-01-01

    ResumenEl objetivo del presente estudio fue evaluar el efecto de un inóculo de levadura Kluyveromyces lactis, obtenida a partir de manzana de desecho de la variedad Golden Delicious en la fermentación en estado sólido (FES) de nopalforrajero Opuntia spp.SummaryThe aim of this study was to evaluate the effect of an inoculum of yeast Kluyveromyces lactis, from apple waste on the variety Golden Delicious in solid state fermentation (SSF) of forage prickly pear cactus Opuntia spp.

  20. Influence of probiotic strain Bifidobacterium animalis subsp. lactis lafti® b94, inulin and transglutaminase on the properties of set- style yoghurt

    OpenAIRE

    Maja Benković; Blaženka Kos; Katarina Tonković; Andreja Leboš; Jagoda Šušković; Ljerka Gregurek

    2008-01-01

    The aim of this research was to examine the influence of probiotic strain Bifidobacterium animalis subsp. lactis LAFTI® B94, inulin and transglutaminase on quality and sensory properties of set-style yoghurt. Fresh, homogenized milk with 3,3% of milk fat was used for yoghurt production, with addition of Bifidobacterium animalis subsp. lactis LAFTI® B94, inulin and transglutaminase activated during 1h 30 min at 55 °C. Enzyme inactivation was carried out by pasteurization of milk during 15 minu...

  1. Structures and host-adhesion mechanisms of lactococcal siphophages

    Directory of Open Access Journals (Sweden)

    ChristianCambillau

    2014-01-01

    Full Text Available The Siphoviridae family of bacteriophages is the largest viral family on earth and comprises members infecting both bacteria and archaea. Lactococcal siphophages infect the Gram-positive bacterium Lactococcus lactis, which is widely used for industrial milk fermentation processes (e.g. cheese production. As a result, lactococcal phages have become one of the most thoroughly characterized class of phages from a genomic standpoint. They exhibit amazing and intriguing characteristics. First, each phage has a strict specificity towards a unique or a handful of L. lactis host strains. Second, most lactococcal phages possess a large organelle at their tail tip (termed the baseplate, bearing the receptor binding proteins and mediating host adsorption. The recent accumulation of structural and functional data revealed the modular structure of their building blocks, their different mechanisms of activation and the fine specificity of their receptor binding proteins. These results also illustrated similarities and differences between lactococcal Siphoviridae and Gram-negative infecting Myoviridae.

  2. Analysis of the human intestinal epithelial cell transcriptional response to Lactobacillus acidophilus, Lactobacillus salivarius, Bifidobacterium lactis and Escherichia coli.

    Science.gov (United States)

    Putaala, H; Barrangou, R; Leyer, G J; Ouwehand, A C; Hansen, E Bech; Romero, D A; Rautonen, N

    2010-09-01

    The complex microbial population residing in the human gastrointestinal tract consists of commensal, potential pathogenic and beneficial species, which are probably perceived differently by the host and consequently could be expected to trigger specific transcriptional responses. Here, we provide a comparative analysis of the global in vitro transcriptional response of human intestinal epithelial cells to Lactobacillus acidophilus NCFM™, Lactobacillus salivarius Ls-33, Bifidobacterium animalis subsp. lactis 420, and enterohaemorrhagic Escherichia coli O157:H7 (EHEC). Interestingly, L. salivarius Ls-33 DCE-induced changes were overall more similar to those of B. lactis 420 than to L. acidophilus NCFM™, which is consistent with previously observed in vivo immunomodulation properties. In the gene ontology and pathway analyses both specific and unspecific changes were observed. Common to all was the regulation of apoptosis and adipogenesis, and lipid-metabolism related regulation by the probiotics. Specific changes such as regulation of cell-cell adhesion by B. lactis 420, superoxide metabolism by L. salivarius Ls-33, and regulation of MAPK pathway by L. acidophilus NCFM™ were noted. Furthermore, fundamental differences were observed between the pathogenic and probiotic treatments in the Toll-like receptor pathway, especially for adapter molecules with a lowered level of transcriptional activation of MyD88, TRIF, IRAK1 and TRAF6 by probiotics compared to EHEC. The results in this study provide insights into the relationship between probiotics and human intestinal epithelial cells, notably with regard to strain-specific responses, and highlight the differences between transcriptional responses to pathogenic and probiotic bacteria. PMID:21831765

  3. Influence of autochthonous lactic acid bacteria on the proteolysis, microstructure and sensory properties of low fat UF cheeses during ripening

    Directory of Open Access Journals (Sweden)

    Dragana Pesic Mikulec

    2012-06-01

    Full Text Available The influence of commercial bacteria Lactococcus lactis ssp. lactis and Lactococcus lactis ssp. cremoris (cheese A and combinations of autochthonous lactic acid bacteria (LAB strains Lactobacillus paracasei ssp. paracasei 08, Lactococcus lactis ssp. cremoris 656, Lactococcus lactis ssp. lactis 653 (cheese B and C on composition, proteolysis, microstructure and sensory properties of low fat cheeses during ripening was investigated. Low fat cast ultra-filtered (UF cheeses were produced according to the defined production procedure by mixing UF milk protein powder, skim milk and cream. Significant influence of different LAB strains on composition, primary proteolysis and microstructure was not found. Cheeses made with autochthonous LAB showed a higher rate of secondary proteolysis, as well as higher flavour scores, and were more acceptable than control cheese.

  4. A novel, lactase-based selection and strain improvement strategy for recombinant protein expression in Kluyveromyces lactis

    Directory of Open Access Journals (Sweden)

    Krijger Jorrit-Jan

    2012-08-01

    Full Text Available Abstract Background The Crabtree-negative yeast species Kluyveromyces lactis has been established as an attractive microbial expression system for recombinant proteins at industrial scale. Its LAC genes allow for utilization of the inexpensive sugar lactose as a sole source of carbon and energy. Lactose efficiently induces the LAC4 promoter, which can be used to drive regulated expression of heterologous genes. So far, strain manipulation of K. lactis by homologous recombination was hampered by the high rate of non-homologous end-joining. Results Selection for growth on lactose was applied to target the insertion of heterologous genes downstream of the LAC4 promoter into the K. lactis genome and found to yield high numbers of positive transformants. Concurrent reconstitution of the β-galactosidase gene indicated the desired integration event of the expression cassette, and β-galactosidase activity measurements were used to monitor gene expression for strain improvement and fermentation optimization. The system was particularly improved by usage of a cell lysis resistant strain, VAK367-D4, which allowed for protein accumulation in long-term fermentation. Further optimization was achieved by increased gene dosage of KlGAL4 encoding the activator of lactose and galactose metabolic genes that led to elevated transcription rates. Pilot experiments were performed with strains expressing a single-chain antibody fragment (scFvox and a viral envelope protein (BVDV-E2, respectively. scFvox was shown to be secreted into the culture medium in an active, epitope-binding form indicating correct processing and protein folding; the E2 protein could be expressed intracellularly. Further data on the influence of protein toxicity on batch fermentation and potential post-transcriptional bottlenecks in protein accumulation were obtained. Conclusions A novel Kluyveromyces lactis host-vector system was developed that places heterologous genes under the control of

  5. Production of N2O and CO2 during the reduction of NO2- by Lactobacillus lactis TS4.

    OpenAIRE

    Dodds, K L; Collins-Thompson, D. L.

    1985-01-01

    N2O was produced during the reduction of NO2- by resting cells of Lactobacillus lactis TS4. At an initial NO2- concentration of 69 micrograms/ml, the rate of N2O production was 1.97 nmol/min per mg of protein, and the recovery of reduced NO2- -N as N2O-N after 24 h was 77%. Higher initial NO2- concentrations decreased both the rate of production of N2O and the recovery of reduced NO2- -N. CO2 production increased during NO2- reduction.

  6. Enzyme activity of β-galactosidase from Kluyveromyces lactis and Aspergillus oryzae on simulated conditions of human gastrointestinal system

    Directory of Open Access Journals (Sweden)

    Alessandra Bosso

    2015-09-01

    Full Text Available An alternative to relieve the symptoms of lactose intolerance is the intake of the enzyme β-galactosidase in pharmaceutical dosage forms. The ability of β-galactosidase produced by Kluyveromyces lactis and Aspergillus oryzae to hydrolyze lactose in simulated conditions of the human gastrointestinal tract was investigated. The experiment was carried out in the optimum temperature for each enzyme activity, 40 and 55°C, respectively, and at the normal human body temperature (37°C at concentrations of 1.5, 3.0, and 5.0 g/L (enzyme from A. oryzae or mL/L (enzyme from K. lactis. Both enzymes were completely inactivated under simulated gastric conditions (pH 2. When the enzymes were subjected to simulated small intestine conditions (pH 7.4, lactose hydrolysis has occurred, but at 37°C the percentage was lower than that under the optimal temperatures. At concentrations of 1.5, 3.0, and 5.0 mL/L the enzyme from K. lactis hydrolyzed 76.63%, 88.91% and 94.80% of lactose at 40°C, and 55.99%, 80.91% and 81.53% at 37°C, respectively. In contrast, the enzyme from A. oryzae hydrolyzed 7.11%, 16.18% and 21.29% at 55°C, and 8.4%, 11.85% and 16.43% at 37°C. It was observed that under simulated intestinal conditions, the enzyme from K. lactis was more effective on lactose hydrolysis as compared to the enzyme from A. oryzae. Considering the findings of this study, it is extremely necessary to use an enteric coating on β-galactosidase capsules so that this enzyme is released only in the small intestine, which is its site of action, thus not suffering the action of the stomach pH.Keywords: Lactase. Hydrolysis. Lactose intolerance. Gastrointestinal tract. RESUMOAtividade de β-galactosidase de Kluyveromyces lactis e Aspergillus oryzae, em condições simuladas do sistema gastrintestinal humanoUma das alternativas para amenizar os sintomas da intolerância à lactose é a ingestão de β-galactosidase em formas farmacêuticas. Neste trabalho avaliou-se a

  7. Regulation of glycolysis and sugar phosphotransferase activities in Streptococcus lactis: growth in the presence of 2-deoxy-D-glucose.

    OpenAIRE

    Thompson, J.; Chassy, B M

    1983-01-01

    Streptococcus lactis K1 has the capacity to grow on many sugars, including sucrose and lactose, in the presence of high levels (greater than 500 mM) of 2-deoxy-D-glucose. Initially, growth of the organism was transiently halted by the addition of comparatively low concentrations (less than 0.5 mM) of the glucose analog to the culture. Inhibition was coincident with (i) rapid accumulation of 2-deoxy-D-glucose 6-phosphate (ca. 120 mM) and preferential utilization of phosphoenolpyruvate via the ...

  8. The Science behind the Probiotic Strain Bifidobacterium animalis subsp. lactis BB-12®

    Directory of Open Access Journals (Sweden)

    Mikkel Jungersen

    2014-03-01

    Full Text Available This review presents selected data on the probiotic strain Bifidobacterium animalis subsp. lactis BB-12® (BB-12®, which is the world’s most documented probiotic Bifidobacterium. It is described in more than 300 scientific publications out of which more than 130 are publications of human clinical studies. The complete genome sequence of BB-12® has been determined and published. BB-12® originates from Chr. Hansen’s collection of dairy cultures and has high stability in foods and as freeze dried powders. Strain characteristics and mechanisms of BB-12® have been established through extensive in vitro testing. BB-12® exhibits excellent gastric acid and bile tolerance; it contains bile salt hydrolase, and has strong mucus adherence properties, all valuable probiotic characteristics. Pathogen inhibition, barrier function enhancement, and immune interactions are mechanisms that all have been demonstrated for BB-12®. BB-12® has proven its beneficial health effect in numerous clinical studies within gastrointestinal health and immune function. Clinical studies have demonstrated survival of BB-12® through the gastrointestinal tract and BB-12® has been shown to support a healthy gastrointestinal microbiota. Furthermore, BB-12® has been shown to improve bowel function, to have a protective effect against diarrhea, and to reduce side effects of antibiotic treatment, such as antibiotic-associated diarrhea. In terms of immune function, clinical studies have shown that BB-12® increases the body’s resistance to common respiratory infections as well as reduces the incidence of acute respiratory tract infections.

  9. Ethanol production by Kluyveromyces lactis immobilized cells in copolymer carriers produced by radiation polymerization.

    Science.gov (United States)

    El-Batal, A I; Farahat, L M; El-Rehim, H A

    2000-01-01

    The conditions for batch and continuous production of ethanol, using immobilized growing yeast cells of Kluyveromyces lactis, have been optimized. Yeast cells have been immobilized in hydrogel copolymer carriers composed of polyvinyl alcohol (PVA) with various hydrophilic monomers, using radiation copolymerization technique. Yeast cells were immobilized through adhesion and multiplication of yeast cells themselves. The ethanol production of immobilized growing yeast cells with these hydrogel carriers was related to the monomer composition of the copolymers and the optimum monomer composition was hydroxyethyl methacrylate (HEMA). In this case by using batch fermentation, the superior ethanol production was 32.9 g L(-1) which was about 4 times higher than that of cells in free system. The relation between the activity of immobilized yeast cells and the water content of the copolymer carriers was also discussed. Immobilized growing yeast cells in PVA: HEMA (7%: 10%, w/w) hydrogel copolymer carrier, were used in a packed-bed column reactor for the continuous production of ethanol from lactose at different levels of concentrations (50, 100 and 150) g L(-1). For all lactose feed concentrations, an increase in dilution rates from 0.1 h(-1) to 0.3 h(-1) lowered ethanol concentration in fermented broth, but the volumetric ethanol productivity and volumetric lactose uptake rate were improved. The fermentation efficiency was lowered with the increase in dilution rate and also at higher lactose concentration in feed medium and a maximum of 70.2% was obtained at the lowest lactose concentration 50 g L(-1). PMID:11093678

  10. Yeasts as Ripening Adjunct Cultures in Turkish White Brined Cheese Production

    OpenAIRE

    Kesenkaş, Harun; Akbulut, Necati

    2008-01-01

    The present study aimed to determine the possibility of using yeasts as adjunct cultures in the production of white brined cheese, which is quite important to the Turkish dairy industry, and to evaluate the effects of these yeasts on cheese ripening. In addition to starter culture (Lactococcus lactis subsp. lactis + Lactococcus lactis subsp. cremoris), adjunct yeast cultures of Yarrowia lipolytica, Debaryomyces hansenii, and Kluyveromyces marxianus were separately co-inoculated to each cheese...

  11. Draft Genome Sequence of Lactococcus garvieae Strain PAQ102015-99, an Outbreak Strain Isolated from a Commercial Trout Farm in the Northwestern United States.

    Science.gov (United States)

    Nelson, Michael C; Varney, Jed S; Welch, Timothy J; Graf, Joerg

    2016-01-01

    We announce the draft genome assembly of Lactococcus garvieae strain PAQ102015-99, a recently isolated strain from an outbreak of lactococcosis at a commercial trout farm in the northwestern United States. The draft genome comprises 14 contigs totaling 2,068,357 bp with an N50 of 496,618 bp and average G+C content of 38%. PMID:27492003

  12. Extreme Ionizing-Radiation-Resistant Bacterium

    Science.gov (United States)

    Vaishampayan, Parag A.; Venkateswaran, Kasthuri J.; Schwendner, Petra

    2013-01-01

    potential for transfer, and subsequent proliferation, on another solar body such as Mars and Europa. These organisms are more likely to escape planetary protection assays, which only take into account presence of spores. Hence, presences of extreme radiation-resistant Deinococcus in the cleanroom facility where spacecraft are assembled pose a serious risk for integrity of life-detection missions. The microorganism described herein was isolated from the surfaces of the cleanroom facility in which the Phoenix Lander was assembled. The isolated bacterial strain was subjected to a comprehensive polyphasic analysis to characterize its taxonomic position. This bacterium exhibits very low 16SrRNA similarity with any other environmental isolate reported to date. Both phenotypic and phylogenetic analyses clearly indicate that this isolate belongs to the genus Deinococcus and represents a novel species. The name Deinococcus phoenicis was proposed after the Phoenix spacecraft, which was undergoing assembly, testing, and launch operations in the spacecraft assembly facility at the time of isolation. D. phoenicis cells exhibited higher resistance to ionizing radiation (cobalt-60; 14 kGy) than the cells of the D. radiodurans (5 kGy). Thus, it is in the best interest of NASA to thoroughly characterize this organism, which will further assess in determining the potential for forward contamination. Upon the completion of genetic and physiological characteristics of D. phoenicis, it will be added to a planetary protection database to be able to further model and predict the probability of forward contamination.

  13. Inhibitory effect of honey-sweetened goat and cow milk fermented with Bifidobacterium lactis Bb-12 on the growth of Listeria monocytogenes

    Directory of Open Access Journals (Sweden)

    Mirela Lučan

    2009-06-01

    Full Text Available The aim of the study was to determine the influence of honey addition on fermentation of goat and cow milk with Bifidobacterium lactis Bb-12. Additionally, inhibitory potential of honey-sweetened fermented goat and cow milk against Listeria monocytogenes strain was examined. Two monofloral honey types, dark-colored chestnut and light-colored acacia honey were added. The basic hypothesis of this study was that addition of honey could have influence on the growth of Bifidobacterium lactis during the fermentation of goat and cow milk. Furthermore, higher inhibitory potential caused by honey addition against Listeria monocytogenes has been assumed. Compared to cow milk, higher acidity and CFU of Bifidobacterium lactis Bb-12 were noted in the fermented goat milk in all phases of the fermentation process. The results of this study show that both types of honey enhanced growth and acidity of the Bifidobacterium lactis Bb-12 in both milk types during fermentation. A disc assay has shown that development of growth inhibition zones depends on the type and concentration of honey, as well as on the milk type. The chestnut honey had generally higher inhibitory effect than acacia honey.

  14. Molybdate Reduction to Molybdenum Blue by an Antarctic Bacterium

    OpenAIRE

    S. A. Ahmad; Shukor, M. Y.; Shamaan, N. A.; W. P. Mac Cormack; Syed, M. A.

    2013-01-01

    A molybdenum-reducing bacterium from Antarctica has been isolated. The bacterium converts sodium molybdate or Mo6+ to molybdenum blue (Mo-blue). Electron donors such as glucose, sucrose, fructose, and lactose supported molybdate reduction. Ammonium sulphate was the best nitrogen source for molybdate reduction. Optimal conditions for molybdate reduction were between 30 and 50 mM molybdate, between 15 and 20°C, and initial pH between 6.5 and 7.5. The Mo-blue produced had a unique absorption spe...

  15. Mezofilik Liyofilize Starter Kültür Kullanılarak Üretilen Tereyağının Bazı Özellikleri

    OpenAIRE

    Bakırcı, İhsan; Çelik, Şerafettin; Coşkun, Hayri

    2004-01-01

    in this study, the mixed strains of lactic acid bacteria [Lactococcus lactis subsp. lactis + Lc. lactis subsp. lactis biovar. diacetylactis (1/1, v/v) and Lc. lactis subsp. cremoris + Lc. lactis subsp. lactis biovar. diacetylactis (1/1, v/v)] were used at ratios of 1 and 2 % for the production of butter. After production, the samples were stored at +4±1 °C for 120 days. Titratable acidity, free fatty acid and peroxide values of butter samples were determined on days 1, 30, 60, 90 and 120 duri...

  16. Influence of probiotic strain Bifidobacterium animalis subsp. lactis lafti® b94, inulin and transglutaminase on the properties of set- style yoghurt

    Directory of Open Access Journals (Sweden)

    Maja Benković

    2008-05-01

    Full Text Available The aim of this research was to examine the influence of probiotic strain Bifidobacterium animalis subsp. lactis LAFTI® B94, inulin and transglutaminase on quality and sensory properties of set-style yoghurt. Fresh, homogenized milk with 3,3% of milk fat was used for yoghurt production, with addition of Bifidobacterium animalis subsp. lactis LAFTI® B94, inulin and transglutaminase activated during 1h 30 min at 55 °C. Enzyme inactivation was carried out by pasteurization of milk during 15 minutes at 85 °C. Control samples were prepared without addition of probiotic culture, inulin and transglutaminase. Physico-chemical parameters and sensory properties of produced set-style yoghurt have been determined. For reliable identification of probiotic strain Bifidobacterium animalis subsp. lactis LAFTI® B94, isolated from the produced yoghurt, SDS-PAGE of whole cell proteins and PCR with species specific primers for Bifidobacterium were carried out. It has been shown that produced set-style yoghurt with probiotic strain Bifidobacterium animalis subsp. lactis LAFTI® B94, inulin and transglutaminase had higher firmness, less syneresis and better sensory properties than control yoghurt samples. After 28 days of storage the viable count of Bifidobacterium animalis subsp. lactis LAFTI® B94 was higher in samples containing inulin as prebiotic. Fermentation of yoghurt samples containing inulin and transglutaminase lasted shorter than fermentation of samples without inulin and transglutaminase. The presence of high number of probiotic culture (more than 106 cells/mL in produced set yoghurts was confirmed by SDS-PAGE of whole cell proteins and PCR with species specific primers for Bifidobacterium

  17. Draft Genome Sequence of Oral Bacterium Streptococcus mutans JH1140

    OpenAIRE

    Escano, Jerome; Deng, Peng; Lu, Shi-En; Smith, Lief

    2016-01-01

    Streptococcus mutans JH1140 is an oral bacterium known to produce the bacteriocin mutacin 1140, and the strain has been genetically engineered to combat dental caries. Here, we report the 2.0-Mb draft genome of S. mutans JH1140. This genome provides new insights into the strain’s superior colonization properties and its utility in replacement therapy.

  18. Genome of a mosquito-killing bacterium decoded

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    @@ Researchers with the CAS Wuhan Institute of Virology (WHIOV) recently completed the genome sequencing of a mosquitocidal bacterium Bacillus shaericus C3-41. The feat, first of its kind in China, is expected to further promote the bio-control studies of mosquitoes.

  19. Rnf Genes in Purple Sulfur Bacterium Allochromatium vinosum

    OpenAIRE

    DİNÇTÜRK, H. Benan; DEMİR, Volkan

    2006-01-01

    Allochromatium vinosum is a photosynthetic, diazotrophic purple sulfur bacterium that oxidizes reduced sulfur compounds hydrogen sulfide, elemental sulfur and thiosulfide. In this article, we report the presence of rnf genes in Allochromatium vinosum, some of which have been reported to take part in nitrogen fixation in some species.

  20. Draft Genome Sequence of Oral Bacterium Streptococcus mutans JH1140

    Science.gov (United States)

    Escano, Jerome; Deng, Peng; Lu, Shi-En

    2016-01-01

    Streptococcus mutans JH1140 is an oral bacterium known to produce the bacteriocin mutacin 1140, and the strain has been genetically engineered to combat dental caries. Here, we report the 2.0-Mb draft genome of S. mutans JH1140. This genome provides new insights into the strain’s superior colonization properties and its utility in replacement therapy. PMID:27257196

  1. Síntese de galacto-oligossacarídeos a partir de lactose usando β-galactosidase comercial de Kluyveromyces lactis Synthesis of galactooligosaccharides from lactose using commercial β-galactosidase from Kluyveromyces lactis

    OpenAIRE

    Cristiane Reinaldo Lisboa; Fátima Aparecida de Almeida Costa; Janaína Fernandes de Medeiros Burkert; Carlos André Veiga Burkert

    2012-01-01

    O objetivo deste trabalho foi estudar a influência de parâmetros reacionais na obtenção via enzimática de galacto-oligossacarídeos (GOS), utilizando-se a enzima comercial β-galactosidase de Kluyveromyces lactis (Lactozym® 3000 L), tendo como substrato a lactose. Foi proposto um planejamento experimental 2³, verificando a influência da temperatura (30 a 40 °C), da concentração de lactose (200 a 400 mg.mL-1) e da concentração de enzima (5 a 10 U.mL-1) no desempenho da reação enzimática. Os...

  2. Ecosystème fromager : de l'étude du métabolisme du soufre chez Kluyveromyces lactis et Yarrowia lipolytica à l'interaction entre Kluyveromyces lactis et Brevibacterium aurantiacum

    OpenAIRE

    Hébert, Agnès

    2010-01-01

    Le métabolisme du soufre, qui occupe une place centrale au sein de la cellule, est aussi important lors de la fabrication des fromages à pâte molle à croûte lavée. L'écosystème fromager assimile les acides aminés soufrés et peut ainsi produire des composés soufrés volatils (CSVs) indispensables à la flaveur de ces produits. Nous avons étudié le métabolisme du soufre chez deux micro-organismes d'affinage, les levures hémiascomycètes Kluyveromyces lactis et Yarrowia lipolytica. L'analyse in sil...

  3. Shotgun Genome Sequence of the Large Purple Photosynthetic Bacterium Rhodospirillum photometricum DSM122

    OpenAIRE

    Duquesne, K.; Sturgis, James N.

    2012-01-01

    Here, we present the shotgun genome sequence of the purple photosynthetic bacterium Rhodospirillum photometricum DSM122. The photosynthetic apparatus of this bacterium has been particularly well studied by microscopy. The knowledge of the genome of this oversize bacterium will allow us to compare it with the other purple bacterial organisms to follow the evolution of the photosynthetic apparatus.

  4. Optimization of process parameters for the continuous ethanol production by Kluyveromyces lactis immobilized cells in hydrogel copolymer carrier.

    Science.gov (United States)

    Deriase, S F; Farahat, L M; El-Batal, A I

    2001-01-01

    In the present study the optimized parameters for highest ethanol productivity by Kluyveromyces lactis immobilized cells bioreactor were obtained using the method of Lagrange multipliers. Immobilized growing yeast cells in PVA: HEMA (7%: 10%, w/w) hydrogel copolymer carrier produced by radiation polymerization were used in a packed-bed column reactor for the continuous production of ethanol from lactose at different levels of concentrations (50, 100 and 150) gL(-1). The results indicate that volumetric ethanol productivity is influenced by substrate concentration and dilution rate. The highest value 7.17 gL(-1) h(-1) is obtained at higher lactose concentration (150 gL(-1)) in feed medium and 0.3 h(-1) dilution rate. The same results have been obtained through the application of "LINGO" software for mathematical optimization. PMID:11518393

  5. Saccharomyces cerevisiae Bat1 and Bat2 aminotransferases have functionally diverged from the ancestral-like Kluyveromyces lactis orthologous enzyme.

    Directory of Open Access Journals (Sweden)

    Maritrini Colón

    Full Text Available BACKGROUND: Gene duplication is a key evolutionary mechanism providing material for the generation of genes with new or modified functions. The fate of duplicated gene copies has been amply discussed and several models have been put forward to account for duplicate conservation. The specialization model considers that duplication of a bifunctional ancestral gene could result in the preservation of both copies through subfunctionalization, resulting in the distribution of the two ancestral functions between the gene duplicates. Here we investigate whether the presumed bifunctional character displayed by the single branched chain amino acid aminotransferase present in K. lactis has been distributed in the two paralogous genes present in S. cerevisiae, and whether this conservation has impacted S. cerevisiae metabolism. PRINCIPAL FINDINGS: Our results show that the KlBat1 orthologous BCAT is a bifunctional enzyme, which participates in the biosynthesis and catabolism of branched chain aminoacids (BCAAs. This dual role has been distributed in S. cerevisiae Bat1 and Bat2 paralogous proteins, supporting the specialization model posed to explain the evolution of gene duplications. BAT1 is highly expressed under biosynthetic conditions, while BAT2 expression is highest under catabolic conditions. Bat1 and Bat2 differential relocalization has favored their physiological function, since biosynthetic precursors are generated in the mitochondria (Bat1, while catabolic substrates are accumulated in the cytosol (Bat2. Under respiratory conditions, in the presence of ammonium and BCAAs the bat1Δ bat2Δ double mutant shows impaired growth, indicating that Bat1 and Bat2 could play redundant roles. In K. lactis wild type growth is independent of BCAA degradation, since a Klbat1Δ mutant grows under this condition. CONCLUSIONS: Our study shows that BAT1 and BAT2 differential expression and subcellular relocalization has resulted in the distribution of the

  6. A Streamlined Strategy for Biohydrogen Production with an Alkaliphilic Bacterium

    Energy Technology Data Exchange (ETDEWEB)

    Elias, Dwayne A [ORNL; Wall, Judy D. [University of Missouri; Mormile, Dr. Melanie R. [Missouri University of Science and Technology; Begemann, Matthew B [University of Wisconsin, Madison

    2012-01-01

    Biofuels are anticipated to enable a shift from fossil fuels for renewable transportation and manufacturing fuels, with biohydrogen considered attractive since it could offer the largest reduction of global carbon budgets. Currently, biohydrogen production remains inefficient and heavily fossil fuel-dependent. However, bacteria using alkali-treated biomass could streamline biofuel production while reducing costs and fossil fuel needs. An alkaliphilic bacterium, Halanaerobium strain sapolanicus, is described that is capable of biohydrogen production at levels rivaling neutrophilic strains, but at pH 11 and hypersaline conditions. H. sapolanicus ferments a variety of 5- and 6- carbon sugars derived from hemicellulose and cellulose including cellobiose, and forms the end products hydrogen and acetate. Further, it can also produce biohydrogen from switchgrass and straw pretreated at temperatures far lower than any previously reported and in solutions compatible with growth. Hence, this bacterium can potentially increase the efficiency and efficacy of biohydrogen production from renewable biomass resources.

  7. Rock Phosphate Solubilization Mechanisms of One Fungus and One Bacterium

    Institute of Scientific and Technical Information of China (English)

    LIN Qi-mei; ZHAO Xiao-rong; ZHAO Zi-juan; LI Bao-guo

    2002-01-01

    Many microorganisms can dissolve the insoluble phosphates like apatite. However, the mechanisms are still not clear. This study was an attempt to investigate the mechanisms of rock phosphate solubilization by an Aspergillus 2TCiF2 and an Arthrobacter1TCRi7. The results indicated that the fungus produced a large amount of organic acids, mainly oxalic acid. The total quantity of the organic acids produced by the fungus was 550 times higher than that by the bacterium. Different organic acids had completely different capacities to solubilize the rock. Oxalic acid and citric acid had stronger capacity to dissolve the rock than malic acid, tartaric acid, lactic acid, acetic acid, malonic acid and succinic acid. The fungus solubilized the rock through excreting both proton and organic acids. The rock solubilization of the bacterium depended on only proton.

  8. A physical map of the hyperthermophilic bacterium Aquifex pyrophilus chromosome.

    OpenAIRE

    Shao, Z; Mages, W; Schmitt, R.

    1994-01-01

    A genomic map of the hyperthermophilic hydrogen-oxidizing bacterium Aquifex pyrophilus was established with NotI (GC/GGCCGC), SpeI (A/CTAGT), and XbaI (T/CTAGA). Linking clones and cross-hybridization of restriction fragments revealed a single circular chromosome of 1.6 Mbp. A single flagellin gene and six rRNA gene units were located on this map by Southern hybridization.

  9. Isolation of a Bacterium Capable of Degrading Peanut Hull Lignin

    OpenAIRE

    Kerr, Thomas J.; Kerr, Robert D.; Benner, Ronald

    1983-01-01

    Thirty-seven bacterial strains capable of degrading peanut hull lignin were isolated by using four types of lignin preparations and hot-water-extracted peanut hulls. One of the isolates, tentatively identified as Arthrobacter sp., was capable of utilizing all four lignin preparations as well as extracted peanut hulls as a sole source of carbon. The bacterium was also capable of degrading specifically labeled [14C]lignin-labeled lignocellulose and [14C]cellulose-labeled lignocellulose from the...

  10. Lactococcus garvieae endocarditis in a native valve identified by MALDI-TOF MS and PCR-based 16s rRNA in Spain: A case report

    Directory of Open Access Journals (Sweden)

    V. Heras Cañas

    2015-05-01

    Full Text Available Lactococcus garvieae is a Gram-positive, catalase negative coccus arranged in pairs or short chains, well-known as a fish pathogen. We report a case of Infective Endocarditis (IE by L. garvieae in a native valve from a 68-year-old male with unknown history of contact with raw fish and an extensive history of heart disease. This case highlights the reliability of MALDI-TOF MS compared to conventional methods in the identification of rare microorganisms like this.

  11. AcEST: BP916885 [AcEST

    Lifescience Database Archive (English)

    Full Text Available |Q02Y66|PUR9_LACLS Bifunctional purine biosynthesis protein purH OS=Lactococcus lactis subsp. cremoris...otein purH OS=Lactococcus lactis subsp. cremoris (strain MG1363) Align leng...otein purH OS=Lactococcus lactis subsp. cremoris (strain MG1363) GN=pu...s-Prot sp_hit_id A2RJY0 Definition sp|A2RJY0|PUR9_LACLM Bifunctional purine biosynthesis pr...|A2RJY0|PUR9_LACLM Bifunctional purine biosynthesis protein pu... 35 0.088 sp|

  12. Polyphasic Screening, Homopolysaccharide Composition, and Viscoelastic Behavior of Wheat Sourdough from a Leuconostoc lactis and Lactobacillus curvatus Exopolysaccharide-Producing Starter Culture

    OpenAIRE

    Palomba, Simona; Cavella, Silvana; Torrieri, Elena; Piccolo, Alessandro; Mazzei, Pierluigi; Blaiotta, Giuseppe; Ventorino, Valeria; Pepe, Olimpia

    2012-01-01

    After isolation from different doughs and sourdoughs, 177 strains of lactic acid bacteria were screened at the phenotypic level for exopolysaccharide production on media containing different carbohydrate sources. Two exopolysaccharide-producing lactic acid bacteria (Lactobacillus curvatus 69B2 and Leuconostoc lactis 95A) were selected through quantitative analysis on solid media containing sucrose and yeast extract. The PCR detection of homopolysaccharide (gtf and lev) and heteropolysaccharid...

  13. Maintenance of Very Long Telomeres by Recombination in the Kluyveromyces lactis stn1-M1 Mutant Involves Extreme Telomeric Turnover, Telomeric Circles, and Concerted Telomeric Amplification

    OpenAIRE

    Xu, Jianing; McEachern, Michael J.

    2012-01-01

    Some cancers utilize the recombination-dependent process of alternative lengthening of telomeres (ALT) to maintain long heterogeneous telomeres. Here, we studied the recombinational telomere elongation (RTE) of the Kluyveromyces lactis stn1-M1 mutant. We found that the total amount of the abundant telomeric DNA in stn1-M1 cells is subject to rapid variation and that it is likely to be primarily extrachromosomal. Rad50 and Rad51, known to be required for different RTE pathways in Saccharomyces...

  14. Salt-inducible promoter derivable from a lactic acid bacterium, and its use in a lactic acid bacterium for production of a desired protein

    NARCIS (Netherlands)

    Sanders, Jan Willem; Kok, Jan; Venema, Gerard; Ledeboer, Adrianus Marinus

    1998-01-01

    The invention provides a salt-inducible promoter present in SEQ ID NO: 10 and derivable from a lactic acid bacterium in isolation from the coding sequence normally controlled by said promoter in a wild-type lactic acid bacterium, with modifications and important parts thereof. Also provided are a re

  15. Predominant genera of fecal microbiota in children with atopic dermatitis are not altered by intake of probiotic bacteria Lactobacillus acidophilus NCFM and Bifidobacterium animalis subsp. lactis Bi-07.

    Science.gov (United States)

    Larsen, Nadja; Vogensen, Finn K; Gøbel, Rikke; Michaelsen, Kim F; Abu Al-Soud, Waleed; Sørensen, Søren J; Hansen, Lars H; Jakobsen, Mogens

    2011-03-01

    The effect of probiotic bacteria Lactobacillus acidophilus NCFM and Bifidobacterium lactis Bi-07 on the composition of the Lactobacillus group, Bifidobacterium and the total bacterial population in feces from young children with atopic dermatitis was investigated. The study included 50 children randomized to intake of one of the probiotic strain or placebo. Microbial composition was characterized by denaturing gradient gel electrophoresis, quantitative PCR and, in a subset of subjects, by pyrosequencing of the 16S rRNA gene. The core population of the Lactobacillus group was identified as Lactobacillus gasseri, Lactobacillus fermentum, Lactobacillus oris, Leuconostoc mesenteroides, while the bifidobacterial community included Bifidobacterium adolescentis, Bifidobacterium bifidum, Bifidobacterium longum and Bifidobacterium catenulatum. The fecal numbers of L. acidophilus and B. lactis increased significantly after intervention, indicating survival of the ingested bacteria. The levels of Bifidobacterium correlated positively (P=0.03), while the levels of the Lactobacillus group negatively (P=0.01) with improvement of atopic eczema evaluated by the Severity Scoring of Atopic Dermatitis index. This correlation was observed across the whole study cohort and not attributed to the probiotic intake. The main conclusion of the study is that administration of L. acidophilus NCFM and B. lactis Bi-07 does not affect the composition and diversity of the main bacterial populations in feces. PMID:21204871

  16. Identification of Restriction-Modification Systems of Bifidobacterium animalis subsp. lactis CNCM I-2494 by SMRT Sequencing and Associated Methylome Analysis

    Science.gov (United States)

    O′Connell Motherway, Mary; Watson, Debbie; Bottacini, Francesca; Clark, Tyson A.; Roberts, Richard J.; Korlach, Jonas; Garault, Peggy; Chervaux, Christian; van Hylckama Vlieg, Johan E. T.; Smokvina, Tamara; van Sinderen, Douwe

    2014-01-01

    Bifidobacterium animalis subsp. lactis CNCM I-2494 is a component of a commercialized fermented dairy product for which beneficial effects on health has been studied by clinical and preclinical trials. To date little is known about the molecular mechanisms that could explain the beneficial effects that bifidobacteria impart to the host. Restriction-modification (R-M) systems have been identified as key obstacles in the genetic accessibility of bifidobacteria, and circumventing these is a prerequisite to attaining a fundamental understanding of bifidobacterial attributes, including the genes that are responsible for health-promoting properties of this clinically and industrially important group of bacteria. The complete genome sequence of B. animalis subsp. lactis CNCM I-2494 is predicted to harbour the genetic determinants for two type II R-M systems, designated BanLI and BanLII. In order to investigate the functionality and specificity of these two putative R-M systems in B. animalis subsp. lactis CNCM I-2494, we employed PacBio SMRT sequencing with associated methylome analysis. In addition, the contribution of the identified R-M systems to the genetic accessibility of this strain was assessed. PMID:24743599

  17. KlSEC53 is an essential Kluyveromyces lactis gene and is homologous with the SEC53 gene of Saccharomyces cerevisiae.

    Science.gov (United States)

    Staneva, Dessislava; Uccelletti, Daniela; Farina, Francesca; Venkov, Pencho; Palleschi, Claudio

    2004-01-15

    Phosphomannomutase (PMM) is a key enzyme, which catalyses one of the first steps in the glycosylation pathway, the conversion of D-mannose-6-phosphate to D-mannose-1-phosphate. The latter is the substrate for the synthesis of GDP-mannose, which serves as the mannosyl donor for the glycosylation reactions in eukaryotic cells. In the yeast Saccharomyces cerevisiae PMM is encoded by the gene SEC53 (ScSEC53) and the deficiency of PMM activity leads to severe defects in both protein glycosylation and secretion. We report here on the isolation of the Kluyveromyces lactis SEC53 (KlSEC53) gene from a genomic library by virtue of its ability to complement a Saccharomyces cerevisiae sec53 mutation. The sequenced DNA fragment contained an open reading frame of 765 bp, coding for a predicted polypeptide, KlSec53p, of 254 amino acids. The KlSec53p displays a high degree of homology with phosphomannomutases from other yeast species, protozoans, plants and humans. Our results have demonstrated that KlSEC53 is the functional homologue of the ScSEC53 gene. Like ScSEC53, the KlSEC53 gene is essential for K. lactis cell viability. Phenotypic analysis of a K. lactis strain overexpressing the KlSEC53 gene revealed defects expected for impaired cell wall integrity. PMID:14745781

  18. 乳球菌介导的重组细菌疫苗的研制现状%Current condition of researches in recombinant bacteria mediated by lactococcus

    Institute of Scientific and Technical Information of China (English)

    李文桂; 陈雅棠

    2016-01-01

    细菌是一种人类感染的常见病原体,研制疫苗防治细菌感染是当前研究的热点领域之一。乳球菌是一种新型疫苗载体,本文阐述了乳球菌介导的肺炎链球菌、化脓链球菌、金黄色葡萄球菌、大肠埃希菌、奇异变形杆菌、流产布鲁菌、鼠疫耶尔森菌、破伤风梭菌、单增李斯特菌、霍乱弧菌、幽门螺杆菌、铜绿假单胞菌和嗜水气单胞菌等细菌疫苗的构建及其作用机制等方面的研制现状。%Bacteria is a common type of human infectious pathogen agent ,whose prevention measure ,vaccine , has become a popular research topic during recent years .Lactococcus is a new type of vaccine carrier .This article reviews the present condition of researches in construction and immune mechanisms of recombinant vaccine of bacteria ,such as Streptococcus pneumoniae ,Streptococcus pyogenes ,Staphylococcus aureus ,Escherichia coli ,Proteus mirabilis ,Brucella abortus ,Yersinia pestis ,Clostridium tetanus ,Listeria monocytogenes ,Vibro cholera ,Helicobacter pylori ,Pseudomonas aeruginosa and Aeromonas hydrophila mediated by lactococcus .

  19. Research Progress and Perspectives of Nitrogen Fixing Bacterium, Gluconacetobacter diazotrophicus, in Monocot Plants

    Directory of Open Access Journals (Sweden)

    N. Eskin

    2014-01-01

    Full Text Available Gluconacetobacter diazotrophicus is a nitrogen fixing bacterium originally found in monocotyledon sugarcane plants in which the bacterium actively fixes atmosphere nitrogen and provides significant amounts of nitrogen to plants. This bacterium mainly colonizes intercellular spaces within the roots and stems of plants and does not require the formation of the complex root organ like nodule. The bacterium is less plant/crop specific and indeed G. diazotrophicus has been found in a number of unrelated plant species. Importantly, as the bacterium was of monocot plant origin, there exists a possibility that the nitrogen fixation feature of the bacterium may be used in many other monocot crops. This paper reviews and updates the research progress of G. diazotrophicus for the past 25 years but focuses on the recent research development.

  20. Phosphate enhances levan production in the endophytic bacterium Gluconacetobacter diazotrophicus Pal5

    OpenAIRE

    Idogawa, Nao; Amamoto, Ryuta; Murata, Kousaku; Kawai, Shigeyuki

    2014-01-01

    Gluconacetobacter diazotrophicus is a gram-negative and endophytic nitrogen-fixing bacterium that has several beneficial effects in host plants; thus, utilization of this bacterium as a biofertilizer in agriculture may be possible. G. diazotrophicus synthesizes levan, a D-fructofuranosyl polymer with β-(2→6) linkages, as an exopolysaccharide and the synthesized levan improves the stress tolerance of the bacterium. In this study, we found that phosphate enhances levan production by G. diazotro...