Publications

cloning, expression, and characterization of the lactococcus lactis pfl gene, encoding pyruvate formate-lyase.	the lactococcus lactis pfl gene, encoding pyruvate formate-lyase (pfl), has been cloned and characterized. the deduced amino acid sequence of the l. lactis pfl. protein showed high similarity to those of other bacterial pfl proteins and included the conserved glycine residue involved in posttranslational activation of pfl. the genetic organization of the chromosomal pfl region in l. lactis showed differences from other characterized pfl loci, with an upstream open reading frame independently tra ...	1997	9294449
effect of citrate on growth of lactococcus lactis subsp. lactis in milk.	the effect of citrate on the growth of lactococcus lactis subsp. lactis var. diacetylactis in milk has been investigated. five strains of lactococcus lactis subsp. lactis var. diacetylactis were compared to their citrate-negative variants, which lack the plasmid coding for citrate permease. in most cases, acidification kinetics and the final bacterial concentration of pure cultures of parental and variant strains did not differ significantly. co-cultures of parental and variant strains, however, ...	1997	9299783
the cross-linking by o-phthalaldehyde of two amino acid residues at the active site of 6-phosphogluconate dehydrogenase.	o-phthalaldehyde inactivates homodimeric, nadp+ dependent, 6-phosphogluconate dehydrogenase from sheep liver, upon formation of a single isoindole derivative per enzyme subunit. this indicates that the thiol group of a cysteine residue or the epsilon-amino group of a lysine residue located within 3 a and crosslinked by the reagent is essential for catalysis. fluorescence analyses of the modified enzyme suggest that the isoindole derivative forms at the binding site of the nicotinamide moiety of ...	1997	9315293
homing of a group ii intron from lactococcus lactis subsp. lactis ml3.	ll.ltrb is a functional group ii intron located within a gene (ltrb) encoding a conjugative relaxase essential for transfer of the lactococcal element prso1. in this work, the ll.ltrb intron was shown to be an independent mobile element capable of inserting into an intronless allele of the ltrb gene. ll.ltrb was not observed to insert into a deletion derivative of the ltrb gene in which the intron splice site was removed. in contrast, a second vector containing a 271-nucleotide segment of ltrb s ...	1997	9324259
isolation and overexpression of a gene encoding an extracellular beta-(1,3-1,4)-glucanase from streptococcus bovis jb1.	streptococcus bovis jb1 was found to produce a 25-kda extracellular enzyme active against beta-(1,3-1,4)-glucans. a gene was isolated encoding a specific beta-(1,3-1,4)-glucanase that corresponds to this size and belongs to glycoside hydrolase family 16. a 4- to 10-fold increase in supernatant beta-glucanase activity was obtained when the cloned beta-glucanase gene was reintroduced into s. bovis jb1 by use of constructs based on the plasmid vector ptrw10 or pil253. the beta-(1,3-1,4)-glucanase g ...	1997	9327538
the m6 protein of streptococcus pyogenes and its potential as a tool to anchor biologically active molecules at the surface of lactic acid bacteria.		1997	9331710
assessment of bacterial physiology in the digestive tract by use of luciferase gene as promoter probe.		1997	9331781
development of a group b streptococcus (gbs) cloning system.		1997	9331820
food-grade controlled lysis of lactococcus lactis for accelerated cheese ripening.	an attractive approach to accelerate cheese ripening is to induce lysis of lactococcus lactis starter strains for facilitated release of intracellular enzymes involvement in flavor formation. controlled expression of the lytic genes lyta and lyth, which encode the lysin and the holin proteins of the lactococcal bacteriophage phi us3, respectively, was accomplished by application of a food-grade nisin-inducible expression system. simultaneous production of lysin and holin is essential to obtain e ...	1997	9335048
design of thermolabile bacteriophage repressor mutants by comparative molecular modeling.	comparative molecular modeling was performed with repressor protein rro of the temperate lactococcus lactis bacteriophage r1t using the known 3d-structures of related repressors in order to obtain thermolabile derivatives of rro. rro residues presumed to stabilize a nonhomologous but structurally conserved hydrophobic pocket, which was shown to be important for thermostability of the escherichia coli bacteriophage lambda repressor ci, were randomized. of the derivatives that exhibited various te ...	1997	9335049
dual role of alpha-acetolactate decarboxylase in lactococcus lactis subsp. lactis.	the alpha-acetolactate decarboxylase gene aldb is clustered with the genes for the branched-chain amino acids (bcaa) in lactococcus lactis subsp. lactis. it can be transcribed with bcaa genes under isoleucine regulation or independently of bcaa synthesis under the control of its own promoter. the product of aldb is responsible for leucine sensibility under valine starvation. in the presence of more than 10 microm leucine, the alpha-acetolactate produced by the biosynthetic acetohydroxy acid synt ...	1997	9335274
genetic analysis of regions involved in replication and cadmium resistance of the plasmid pnd302 from lactococcus lactis.	the 8.8-kb lactococcus lactis plasmid pnd302 encodes resistance to cadmium (cdr). regions of pnd302 involved in replication and cdr were subcloned and sequenced. the replication region is localized on a 1.5-kb region and consists of an open reading frame (repb) preceded by a noncoding at-rich sequence (ori) which is highly homologous to lactococcal theta-type replicons. the cdr determinant is localized on a 2.9-kb region and encodes putative proteins similar to the cd(2+)-specific p-type efflux ...	1997	9339465
a new family of k+ transporters from arabidopsis that are conserved across phyla.	transport of k+ in higher plants, as in bacteria and fungi, is mediated by two broad classes of transport proteins that operate in the millimolar and micromolar k+ concentration ranges. a search of the expressed sequence tag database using amino acid consensus sequences for the k+ transporters hak1 from schwanniomyces and kup of escherichia coli yielded two homologous sequences for arabidopsis. cloning and sequencing of these genes gave single open reading frames for the putative transporters, a ...	1997	9350997
combined effect of bacteriocin-producing lactic acid bacteria and lactoperoxidase system activation on listeria monocytogenes in refrigerated raw milk.	the bactericidal activity of three bacteriocin-producing lactic acid bacteria alone and in combination with milk lactoperoxidase (lp) system activation against listeria monocytogenes in refrigerated raw milk was studied. after 4 d at 4 degrees c, the population of l. monocytogenes in milk inoculated with bacteriocin-producing lactococcus lactis subsp. lactis atcc 11454, l. lactis subsp. lactis esi 515 or enterococcus faecalis inia 4 was reduced by 0.21-0.24 log units. activation of the lp system ...	1997	9351220
isolation and characterization of nisin-producing lactococcus lactis subsp. lactis from bean-sprouts.	bacterial isolates from bean-sprouts were screened for anti-listeria monocytogenes bacteriocins using a well diffusion method. thirty-four of 72 isolates inhibited the growth of l. monocytogenes scott a. one, hpb 1688, which had the biggest inhibition zone against l. monocytogenes scott a, was selected for subsequent analysis. both ribotyping and dna sequencing of 16s ribosomal rna gene demonstrated that the isolate was lactococcus lactis subsp. lactis. polymerase chain reaction and nucleotide s ...	1997	9351230
nisin production by lactococcus lactis using two-phase batch culture.	nisin production by lactococcus lactis subsp. lactis c2smprt-(tnnip) was investigated using two-phase batch culture. a solvent (phenyl-methyl silicone oil) was introduced in addition to the aqueous phase. the partition coefficient of this solvent in aqueous nisin varied as the cultivation medium changed, with a minimum value being 1.04. the two-phase batch culture supported a 21% increase in growth and a 24% increase in the level of nisin produced compared to the single-phase batch culture.	1997	9351257
heterologous gene expression of bovine plasmin in lactococcus lactis.	heterologous production of bovine plasmin was studied in the industrially relevant bacterium lactococcus lactis. two sets of lactococcal gene expression signals were coupled to the region of the plasmin gene coding for the serine protease domain. when the promoter region of the prtp gene was used, plasmin was detected mainly intracellularly in strain bpl25 by western blot hybridization. the intracellular presence of plasmin led to physiological stress. expression of the plasmin gene driven by th ...	1997	9352676
a triggered-suicide system designed as a defense against bacteriophages.	a novel bacteriophage protection system for lactococcus lactis based on a genetic trap, in which a strictly phage-inducible promoter isolated from the lytic phage phi31 is used to activate a bacterial suicide system after infection, was developed. the lethal gene of the suicide system consists of the three-gene restriction cassette llair+, which is lethal across a wide range of gram-positive bacteria. the phage-inducible trigger promoter (phi31p) and the llair+ restriction cassette were cloned i ...	1997	9352925
a bacterial group ii intron encoding reverse transcriptase, maturase, and dna endonuclease activities: biochemical demonstration of maturase activity and insertion of new genetic information within the intron.	the lactococcus lactis group ii intron ll.ltrb is similar to mobile yeast mtdna group ii introns, which encode reverse transcriptase, rna maturase, and dna endonuclease activities for site-specific dna insertion. here, we show that the lactococcal intron can be expressed and spliced efficiently in escherichia coli. the intron-encoded protein ltra has reverse transcriptase and rna maturase activities, with the latter activity shown both in vivo and in vitro, a first for any group ii intron-encode ...	1997	9353259
intracellular ph is a major factor in the induction of tolerance to acid and other stresses in lactococcus lactis.	this study demonstrates that exposure of log-phase lactococcus lactis subsp. cremoris 712 cells to mildly acid conditions induces resistance to normally lethal intensities of environmental stresses such as acid, heat, nacl, h2o2, and ethanol. the intracellular ph (phi) played a major role in the induction of this multistress resistance response. the phi was dependent on the extracellular ph (pho) and on the specific acid used to reduce the pho. when resuspended in fresh medium, cells were able t ...	1997	9361406
characterization of the lacticin 481 operon: the lactococcus lactis genes lctf, lcte, and lctg encode a putative abc transporter involved in bacteriocin immunity.	the lantibiotic lacticin 481 is a bacteriocin produced by lactococcus lactis strains. the genetic determinants of lacticin 481 production are organized as an operon encoded by a 70-kb plasmid. we previously reported the first three genes of this operon, lcta, lctm, and lctt, which are involved in the bacteriocin biosynthesis and export (a. rincé, a. dufour, s. le pogam, d. thuault, c. m. bourgeois, and j.-p. le pennec, appl. environ. microbiol. 60:1652-1657, 1994). the operon contains three addi ...	1997	9361411
bacteriophage-triggered defense systems: phage adaptation and design improvements.	a novel bacteriophage defense system, based on an inducible suicide gene, was challenged with a lactococcal bacteriophage to investigate the potential for phage adaptation. the defense system was encoded by ptrk414h, a high-copy-number replicon encoding a tightly regulated phi 31p trigger promoter fused to the lethal llair+ restriction endonuclease cassette. repeated transfers of lactococcus lactis nck690(ptrk414h) in the presence of phi 31 selected for phage phi 31 derivatives which were marked ...	1997	9361424
controlled gene expression systems for lactic acid bacteria: transferable nisin-inducible expression cassettes for lactococcus, leuconostoc, and lactobacillus spp.	a transferable dual-plasmid inducible gene expression system for use in lactic acid bacteria that is based on the autoregulatory properties of the antimicrobial peptide nisin produced by lactococcus lactis was developed. introduction of the two plasmids allowed nisin-inducible gene expression in lactococcus lactis mg1363, leuconostoc lactis nz6091, and lactobacillus helveticus cnrz32. typically, the beta-glucuronidase activity (used as a reporter in this study) remained below the detection limit ...	1997	9361443
application of the extracellular alpha-amylase gene from streptococcus bovis 148 to construction of a secretion vector for yogurt starter strains.	streptococcus thermophilus atcc 19258, lactobacillus delbrueckii subsp. bulgaricus t-11, and lactococcus lactis subsp. lactis il1403 were transformed with the alpha-amylase gene (amya) from streptococcus bovis 148 by using a wide host-range vector, and all the transformants secreted the alpha-amylase successfully. since the promoter and the secretion signal of the amya gene were functional in these strains, we constructed a secretion vector using the expression elements of amya. trials to secret ...	1997	9361445
experimental evidence for the essential role of the c-terminal residue in the strict aminopeptidase activity of the thiol aminopeptidase pepc, a bacterial bleomycin hydrolase.	pepcs isolated from lactic acid bacteria and bleomycin hydrolases of eukaryotic organisms are strict aminopeptidases which belong to the papain family of thiol peptidases. the structural basis of the enzymic specificity of the lactococcal pepc has been investigated by site-directed mutagenesis. the deletion of the c-terminal residue (ala-435) abolished the aminopeptidase activity, whereas this deletion led to a new peptidase specificity. the enzymic properties of wild-type and mutant pepcs demon ...	1997	9371686
the lytic enzyme of the pneumococcal phage dp-1: a chimeric lysin of intergeneric origin.	we have localized, cloned and characterized the genes coding for the lytic system of the pneumococcal phage dp-1. the lytic enzyme of this phage (pal), previously identified as an n-acetyl-muramoyl-l-alanine amidase, shows a modular organization similar to that described for the lytic enzymes of streptococcus pneumoniae and its bacteriophages. the construction of chimeric enzymes between pneumococcus and bacteria (or phages) that belong to different gram-positive families has shown that the inte ...	1997	9379901
analysis of the dna sequence, gene expression, origin of replication and modular structure of the lactococcus lactis lytic bacteriophage sk1.	bacteriophage sk1 is a small isometric-headed lytic phage belonging to the 936 species. it infects lactococcus lactis, a commonly used dairy starter organism. nucleotide sequence data analysis indicated that the sk1 genome is 28,451 nucleotides long and contains 54 open reading frames (orfs) of 30 or more codons, interspersed with three large intergenic regions. the nucleotide sequence of several of the sk1 orfs demonstrated significant levels of identity to genes (many encoding proteins of unkn ...	1997	9383189
the effect of nisin concentration and nutrient depletion on nisin production of lactococcus lactis.	the kinetics of nisin production was studied in batch cultures using a construct of lactococcus lactis subsp. lactis c2smprt-, containing a transposon (tnnip) that encodes nisin production. the introduction of tnnip into c2smprt- significantly lowered the specific growth rate and the maximum a620 reached was reduced from 15.2 to 11.0. the effect of nisin concentration and nutrient depletion on nisin production of the construct, c2smprt-(tnnip), was examined. nisin production was found to be inhi ...	1997	9390452
active site of dihydroorotate dehydrogenase a from lactococcus lactis investigated by chemical modification and mutagenesis.	the flavin-containing enzyme dihydroorotate dehydrogenase (dhod) catalyzes the oxidation of dihydroorotate (dho) to orotate, the first aromatic intermediate in pyrimidine biosynthesis. the first structure of a dhod, the a form of the enzyme from lactococcus lactis, has recently become known, and some conserved residues were suggested to have a role in the active site [rowland et al. (1997) structure 2, 239-252]. in particular, cys 130 was hypothesized to work as a base, which activates dihydroor ...	1997	9405053
purification and partial characterization of a tripeptidase from pediococcus pentosaceus k9.2.	a tripeptidase was purified from the cytoplasm of pediococcus pentosaceus k9.2 by anion-exchange chromatography, gel filtration chromatography, and high-performance liquid chromatography. the molecular mass of the enzyme was estimated by gel filtration at 100,000 da. sodium dodecyl sulfate-polyacrylamide gel electrophoresis of the purified peptidase showed one protein band of 45,000 da. optimal enzyme activity was obtained at ph 7.0 and at 50 degrees c. the peptidase hydrolyzed all tripeptides t ...	1997	9406407
a chloride-inducible gene expression cassette and its use in induced lysis of lactococcus lactis.	a chloride-inducible promoter previously isolated from the chromosome of lactococcus lactis (j. w. sanders, g. venema, j. kok, and k. leenhouts, mol. gen. genet., in press) was exploited for the inducible expression of homologous and heterologous genes. an expression cassette consisting of the positive-regulator gene gadr, the chloride-inducible promoter pgad, and the translation initiation signals of gadc was amplified by pcr. the cassette was cloned upstream of escherichia coli lacz, the holin ...	1997	9406408
one-step purification of nisin a by immunoaffinity chromatography.	the lantibiotic nisin a was purified to homogeneity by a single-step immunoaffinity chromatography method. an immunoadsorption matrix was developed by direct binding of anti-nisin a monoclonal antibodies to n-hydroxysuccinimide-activated sepharose. the purification procedure was rapid and reproducible and rendered much higher final yields of nisin than any other described method.	1997	9406424
determinant role of e. coli rnase iii in the decay of both specific and heterologous mrnas.	a comparative analysis of mrna decay was carried out in escherichia coli using the wild-type and an isogenic rnase iii deletion strain. we have studied the mrna degradation from the escherichia coli gene bola, the lactococcus lactis biovar diacetylactis citqrp operon and the desulfovibrio vulgaris hildenborough gene cyc. as seen by a dramatic stabilization of the specific mrnas in the mutant strain, rnase iii was crucial for the decay process of these three messages. since rnase iii, unlike rnas ...	1997	9418237
autolysis of lactococcus lactis ssp. lactis and lactobacillus casei ssp. casei. cell lysis induced by a crude bacteriocin.	autolytic properties of lactococcus lactis subsp. lactis ifpl359, its lac prt derivative lc. lactis tl and lactobacillus casei subsp. casei ifpl731, used as starter and adjunct starter in goat's milk cheese making, have been studied. the lytic effect of a bacteriocin produced by a lactic acid bacterium isolated from raw goat's milk has also been analyzed. lactococcal cells resuspended in phosphate buffer showed a peak of autolysis when they were harvested in the early growth phase. a more stable ...	1997	9506278
an aminotransferase from lactococcus lactis initiates conversion of amino acids to cheese flavor compounds.	the enzymatic degradation of amino acids in cheese is believed to generate aroma compounds and therefore to be involved in the complex process of cheese flavor development. in lactococci, transamination is the first step in the degradation of aromatic and branched-chain amino acids which are precursors of aroma compounds. here, the major aromatic amino acid aminotransferase of a lactococcus lactis subsp. cremoris strain was purified and characterized. the enzyme transaminates the aromatic amino ...	1997	9023921
the ldh phylogeny for environmental isolates of lactococcus lactis is consistent with rrna genotypes but not with phenotypes.	lactate dehydrogenase (ldh) gene sequences, levels of 16s rrna group-specific probe binding, and phenotypic characteristics were compared for 45 environmental isolates and four commercial starter strains of lactococcus lactis to identify evolutionary groups best suited to cheddar cheese manufacture, ldh sequences from the environmental isolates showed high similarity to those from two groups of l. lactis used for industrial fermentations, l. lactis subsp. cremoris and subsp. lactis. within each ...	1997	9023947
lactic acid bacteria: hydrophobicity and strength of attachment to meat surfaces.	the hydrophobicity and strength of attachment of several lactic acid bacteria with antimicrobial activity were studied. hydrophobicity was determined by bacterial adherence to hydrocarbons (bath; octane or xylene), adhesion to nitrocellulose filters (ncf), salt aggregation test (sat) and adherence to phenyl-sepharose beads (psb). the relative hydrophobicity of lactic acid bacteria depended markedly on the method used. no correlation between either sat or bath (octane) and strength of attachment ...	1997	9023999
the crystal structure of the flavin containing enzyme dihydroorotate dehydrogenase a from lactococcus lactis.	. dihydroorotate dehydrogenase (dhod) is a flavin mononucleotide containing enzyme, which catalyzes the oxidation of (s)-dihydroorotate to orotate, the fourth step in the de novo biosynthesis of pyrimidine nucleotides. lactococcus lactis contains two genes encoding different functional dhods whose sequences are only 30% identical. one of these enzymes, dhoda, is a highly efficient dimer, while the other, dhodb, shows optimal activity only in the presence of an iron-sulphur cluster containing pro ...	1997	9032071
antitermination of transcription of catabolic operons.	antitermination of transcription mediated by proteins interacting with mrna sequences is described for nine operons/regulons. eight of the systems are catabolic, while the ninth, the klebsiella pneumoniae nas regulon, is involved in the assimilation of nitrate and nitrite. six of the catabolic operons/regulons are found in bacillus subtilis, one is found in escherichia coli, and one in pseudomonas aeruginosa. the antitermination system of five of the operons/regulons (e. coli blg, and sacpa, sac ...	1997	9044276
the lac operon of lactobacillus casei contains lact, a gene coding for a protein of the bg1g family of transcriptional antiterminators.	the 5' region of the lac operon of lactobacillus casei has been investigated. an open reading frame of 293 codons, designated lact, was identified upstream of lace. the gene product encoded by lact is related to the family of transcriptional antiterminator proteins, which includes bglg from escherichia coli, arbg from erwinia chrysanthemi, sact, sacy, and lict from bacillus subtilis, and bglr from lactococcus lactis. amino acid sequence identities range from 35 to 24%, while similarities range f ...	1997	9045813
a c-methyltransferase involved in both ubiquinone and menaquinone biosynthesis: isolation and identification of the escherichia coli ubie gene.	strains of escherichia coli with mutations in the ubie gene are not able to catalyze the carbon methylation reaction in the biosynthesis of ubiquinone (coenzyme q) and menaquinone (vitamin k2), essential isoprenoid quinone components of the respiratory electron transport chain. this gene has been mapped to 86 min on the chromosome, a region where the nucleic acid sequence has recently been determined. to identify the ubie gene, we evaluated the amino acid sequences encoded by open reading frames ...	1997	9045837
the role of transport processes in survival of lactic acid bacteria. energy transduction and multidrug resistance.	lactic acid bacteria play an essential role in many food fermentation processes. they are anaerobic organisms which obtain their metabolic energy by substrate phosphorylation. in addition three secondary energy transducing processes can contribute to the generation of a proton motive force: proton/substrate symport as in lactic acid excretion, electrogenic precursor/product exchange as in malolactic and citrolactic fermentation and histidine/histamine exchange, and electrogenic uniport as in mal ...	1997	9049023
the possible role of aminopeptidases from starter culture lactococcus lactis subspecies cremoris am2 in cheese making.		1997	9057017
cloning and molecular analysis of promoter-like sequences isolated from the chromosomal dna of lactobacillus acidophilus atcc 4356.	promoter-like sequences from the chromosomal dna of thermophilic strain lactobacillus acidophilus atcc 4356 were cloned. analysis of the three dna fragments showing promoter activity, designated p3, p6, and p15, were performed in lactobacillus reuteri, lactococcus lactis, and e. coli. the reporter cat-86 gene was expressed in all three bacterial species under control of the fragments p3 and p6. fragment p15 showed promoter activity only in lactobacillus reuteri and e. coli but not in lactococcus ...	1997	9057296
engineering pathways for malate degradation in saccharomyces cerevisiae.	deacidification of grape musts is crucial for the production of well-balanced wines, especially in colder regions of the world. the major acids in wine are tartaric and malic acid. saccharomyces cerevisiae cannot degrade malic acid efficiently due to the lack of a malate transporter and the low substrate affinity of its malic enzyme. we have introduced efficient pathways for malate degradation in s. cerevisiae by cloning and expressing the schizosaccharomyces pombe malate permease (mae1) gene wi ...	1997	9062925
plasmid integration in a wide range of bacteria mediated by the integrase of lactobacillus delbrueckii bacteriophage mv4.	bacteriophage mv4 is a temperate phage infecting lactobacillus delbrueckii subsp. bulgaricus. during lysogenization, the phage integrates its genome into the host chromosome at the 3' end of a trna(ser) gene through a site-specific recombination process (l. dupont et al., j. bacteriol., 177:586-595, 1995). a nonreplicative vector (pmc1) based on the mv4 integrative elements (attp site and integrase-coding int gene) is able to integrate into the chromosome of a wide range of bacterial hosts, incl ...	1997	9068626
high level heterologous protein production in lactococcus and lactobacillus using a new secretion system based on the lactobacillus brevis s-layer signals.	a secretion cassette, based on the expression and secretion signals of a s-layer protein (slpa) from lactobacillus brevis, was constructed. e. coli beta-lactamase (bla) was used as the reporter protein to determine the functionality of the s-layer signals for heterologous expression and secretion in lactococcus lactis, lactobacillus brevis, lactobacillus plantarum, lactobacillus gasseri and lactobacillus casei using a low-copy-number plasmid derived from pgk12. in all hosts tested, the bla gene ...	1997	9074504
use of an immobilized cell bioreactor for the continuous inoculation of milk in fresh cheese manufacturing.	a system was developed to continuously acidify and inoculate skim milk for the production of fresh cheese. four strains of mesophilic lactic acid bacteria were entrapped separately in kappa-carrageenan/locust bean gum gel beads and used in a stirred bioreactor operated at 26 degrees c with a 25% (v/v) gel load. the ph in the reactor was controlled at 6.0 by adding fresh milk using proportional integrated derived regulation. the bioreactor was operated during 8-h daily cycles for up to 7 weeks wi ...	1997	9079289
primary and secondary structures of rrna spacer regions in enterococci.	the 16s-23s and 23s-5s rrna spacer dna regions (spacer regions 1 and 2, respectively) from enterococcus faecalis, enterococcus faecium, enterococcus hirae, enterococcus durans and enterococcus mundtii were amplified by pcr. their nucleotide sequences were established and a secondary structure model showing the interaction between the two spacer regions was built. whereas lactococci and streptococcus sensu stricto are characterized by a single type of spacer region 1, the enterococci show a high ...	1997	9084166
product formation and phosphoglucomutase activities in lactococcus lactis: cloning and characterization of a novel phosphoglucomutase gene.	maltose metabolism in lactococcus lactis involves the conversion of beta-glucose 1-phosphate to glucose 6-phosphate, a reaction which is reversibly catalysed by a maltose-inducible and glucose-repressible beta-phosphoglucomutase (beta-pgm). the gene encoding beta-pgm (pgmb) was cloned from a genomic library of l. lactis using antibodies. the nucleotide sequence of a 5695 bp fragment was determined and six orfs, including the pgmb gene, were found. the gene expressed a polypeptide with a calculat ...	1997	9084169
microbial dynamics of co- and separately entrapped mixed cultures of mesophilic lactic acid bacteria during the continuous prefermentation of milk.	four strains of mesophilic lactic acid bacteria were separately or coentrapped in kappa-carrageenan/locust bean gum gel beads and used for continuous prefermentation of uht skim milk in a stirred-tank bioreactor. lactic acid and cell productivities of the immobilized cell bioreactor were particularly high and remarkably stable during eight weeks of continuous milk prefermentation (about 18 g h-1 l-1 of lactic acid and 4.9 x 10(12) cfu h-1 l-1, respectively, but important variations of the bacter ...	1997	9084207
a novel plasmid-encoded phage abortive infection system from lactococcus lactis biovar. diacetylactis.	a 16-kb plasmid (pnd859) was identified from lactococcus lactis biovar. diacetylactis uk12922 which encodes phage resistance to the small isometric phage 712 when tested in l. lactis lm0230. the gene encoding phage abortive infection, designated abi-859, was localized on a 1.2-kb region which consists of an open reading frame (orf) of 846 bp preceded by a potential ribosome-binding site and a putative promoter region. a helix-turn-helix region typical of dna-binding motifs was identified near th ...	1997	8997719
role of transmembrane ph gradient and membrane binding in nisin pore formation.	nisin is a cationic antimicrobial peptide that belongs to the group of lantibiotics. it is thought to form oligomeric pores in the target membrane by a mechanism that requires the transmembrane electrical potential delta psi and that involves local pertubation of the lipid bilayer structure. here we show that nisin does not form exclusively voltage-dependent pores: even in the absence of a delta psi, nisin is able to dissipate the transmembrane ph gradient (delta ph) in sensitive lactococcus lac ...	1997	8981990
a survey of polypeptide deformylase function throughout the eubacterial lineage.	n-terminal formylation of ribosome-synthesized polypeptides is assumed to be among the most conserved features that distinguish the eubacterial line of descent from other living phyla. in order to assess the ancientness of this trait, def genes encoding polypeptide deformylase were characterized from four eubacterial species, lactococcus lactis, bacillus subtilis, calothrix pcc7601 and thermotoga maritima, taking advantage of the conditional viability of the def mutants of escherichia coli. alto ...	1997	9086272
structure-function relations of variant and fragment nisins studied with model membrane systems.	nisin, a 34 residue lantibiotic produced by strains of lactococcus lactis subsp. lactis, exerts antimicrobial activity against gram-positive bacteria at the cytoplasmic membrane. the structural aspects of nisin which facilitate membrane interaction and permeabilization have been investigated in planar lipid bilayers and liposomes with proteolytic fragments and site-directed variants. n-terminal nisin fragments n1-12 and n1-20 had little effect on phospholipid mobility, on macroscopic electrical ...	1997	9092809
phenotypic and genetic characterization of the bacteriophage abortive infection mechanism abik from lactococcus lactis.	the natural plasmid psrq800 isolated from lactococcus lactis subsp. lactis w1 conferred strong phage resistance against small isometric phages of the 936 and p335 species when introduced into phage-sensitive l. lactis strains. it had very limited effect on prolate phages of the c2 species. the phage resistance mechanism encoded on psrq800 is a temperature-sensitive abortive infection system (abi). plasmid psrq800 was mapped, and the abi genetic determinant was localized on a 4.5-kb ecori fragmen ...	1997	9097424
application and evaluation of the phage resistance- and bacteriocin-encoding plasmid pmrc01 for the improvement of dairy starter cultures.	the conjugative 63-kb lactococcal plasmid pmrc01 encodes bacteriophage resistance and production of and immunity to a novel broad-spectrum bacteriocin, designated lacticin 3147 (m.p. ryan, m.c. rea, c. hill, and r.p. ross, appl. environ. microbiol. 62:612-619, 1996). the phage resistance is an abortive infection mechanism which targets the phage-lytic cycle at a point after phage dna replication. by using the genetic determinants for bacteriocin immunity encoded on the plasmid as a selectable ma ...	1997	9097441
characterization of a thiol-dependent endopeptidase from lactobacillus helveticus cnrz32.	an endopeptidase gene (pepe) was isolated from a previously constructed genomic library of lactobacillus helveticus cnrz32. the pepe gene consisted of a 1,314-bp open reading frame encoding a putative peptide of 52.1 kda. significant identity was found between the deduced amino acid sequence of pepe and the sequences for aminopeptidase c from lactobacillus delbrueckii subsp. lactis dsm7290, l. helveticus cnrz32, streptococcus thermophilus cnrz302, and lactococcus lactis subsp. cremoris am2. a re ...	1997	9098049
a highly efficient and stable system for site-specific integration of genes and plasmids into the phage philc3 attachment site (attb) of the lactococcus lactis chromosome.	an integration vector system based on the site-specific integration apparatus of the temperate lactococcal bacteriophage philc3 was developed. a 1.6-kb recombinogenic dna cassette, containing the philc3 integrase gene (int) and the phage attachment site (attp), mediated site-specific integration of a single marker-gene, as well as of a replication-thermosensitive (-ts) plasmid (pint2), into the philc3 attb site of lactococcus lactis subsp. lactis lm0230 chromosome after introduction of the dna i ...	1997	9099871
double-glycine-type leader peptides direct secretion of bacteriocins by abc transporters: colicin v secretion in lactococcus lactis.	many non-lantibiotic bacteriocins of lactic acid bacteria are produced as precursors which have n-terminal leader peptides that share similarities in amino acid sequence and contain a conserved processing site of two glycine residues in positions -1 and -2. a dedicated atp-binding cassette (abc) transporter is responsible for the proteolytic cleavage of the leader peptides and subsequent translocation of the bacteriocins across the cytoplasmic membrane. to investigate the role that these leader ...	1997	9106219
structure-function relationships within the peptide deformylase family. evidence for a conserved architecture of the active site involving three conserved motifs and a metal ion.	thermus thermophilus peptide deformylase was characterized. its enzymatic properties as well as its organization in domains proved to share close resemblances with those of the escherichia coli enzyme despite few sequence identities. in addition to the hexxh signature sequence of the zinc metalloprotease family, a second short stretch of strictly conserved amino acids was noticed, egcls, the cysteine of which corresponds to the third zinc ligand. the study of site-directed mutants of the e. coli ...	1997	9126850
changes in the concentrations of free amino acids in milk during growth of lactococcus lactis indicate biphasic nitrogen metabolism.	analysis of the concentrations of free amino acids in milk during growth of lactococcus lactis subsp, lactis revealed a biphasic pattern of change during the logarithmic phase. during the first period there was little overall change in the total concentration of amino acids in the medium. the second phase was characterized by increased net liberation of free amino acids. there were also qualitative differences in the amino acids that were taken up and utilized during each period. the concentrati ...	1998	9513058
the s-layer gene of lactobacillus helveticus cnrz 892: cloning, sequence and heterologous expression.	lactobacillus helveticus cnrz 892 contains a surface layer (s-layer) composed of protein monomers of 43 kda organized in regular arrays. the gene encoding this protein (slph) has been cloned in escherichia coli and sequenced. slph consists of 440 codons and is preceded by a ribosome-binding site (rbs) and followed by a putative rho-independent terminator. indeed, northern analysis revealed that slph is a monocistronic gene. the gene is preceded by a possible promotor of which the -35 and -10 hex ...	1998	9534241
control of expression of llai restriction in lactococcus lactis.	the plasmid encoded llai r/m system from lactococcus lactis ssp. lactis consists of a bidomain methylase, with close evolutionary ties to type iis methylases, and a trisubunit restriction complex. both the methylase and restriction subunits are encoded on a polycistronic 6.9 kb operon. in this study, the 5' end of the llal 6.9 kb transcript was determined by primer extension analysis to be 254 bp upstream from the first r/m gene on the operon, llalm. deletion of this promoter region abolished ll ...	1998	9535090
a nine-residue synthetic propeptide enhances secretion efficiency of heterologous proteins in lactococcus lactis.	lactococcus lactis, a gram-positive organism widely used in the food industry, is a potential candidate for the secretion of biologically useful proteins. we examined the secretion efficiency and capacity of l. lactis by using the staphylococcus aureus nuclease (nuc) as a heterologous model protein. when expressed in l. lactis from an efficient lactococcal promoter and its native signal peptide, only approximately 60% of total nuc was present in a secreted form at approximately 5 mg per liter. t ...	1998	9537390
an export-specific reporter designed for gram-positive bacteria: application to lactococcus lactis.	the identification of exported proteins by fusion studies, while well developed for gram-negative bacteria, is limited for gram-positive bacteria, in part due to drawbacks of available export reporters. in this work, we demonstrate the export specificity and use of the staphylococcus aureus secreted nuclease (nuc) as a reporter for gram-positive bacteria. nuc devoid of its export signal (called delta(sp)nuc) was used to create two fusions whose locations could be differentiated. nuclease activit ...	1998	9537391
identification of lactococcus garvieae by pcr.	lactococcus garvieae junior synonym enterococcus seriolicida) is an emerging zoonotic agent isolated from economically important fish (rainbow trout and yellowtail), from cattle, and from humans. clindamycin susceptibility is the only phenotypic test which can differentiate l. garvieae from lactococcus lactis, another emerging agent in humans. a pcr assay for the identification of l. garvieae was developed and resulted in an amplified fragment of 1,100 bp in size. the pcr assay was shown to be s ...	1998	9542921
catalytic properties of the cysteine aminopeptidase pepc, a bacterial bleomycin hydrolase.	pepc is a cytoplasmic thiol aminopeptidase widely conserved among lactic acid bacteria. pepc from lactococcus lactis shares 35-38% identity with aminopeptidases of eukaryotic origins: the yeast and mammalian bleomycin hydrolases (blmase). in this work we investigated the hydrolytic activity of pepc towards various substrates: bleomycin a2, aminoacyl-p-nitroanilides (pna) and peptides. first, we found the bleomycin hydrolase activity of lactococcal pepc and measured similar kinetics parameters to ...	1998	9546047
specificity of milk peptide utilization by lactococcus lactis.	to study the substrate specificity of the oligopeptide transport system of lactococcus lactis for its natural substrates, the growth of l. lactis mg1363 was studied in a chemically defined medium containing milk peptides or a tryptic digest of alpha s2-casein as the source of amino acids. peptides were separated into acidic, neutral, and basic pools by solid-phase extraction or by cation-exchange liquid chromatogrpaphy. their ability to sustain growth and the time course of their utilization dem ...	1998	9546157
an origin of transfer (orit) on the conjugative element prs01 from lactococcus lactis subsp. lactis ml3.	previous analysis of the tra1 region of the conjugative element prs01 from lactococcus lactis subsp. lactis ml3 suggested that an origin of transfer (orit) was present. deletion derivatives of this cloned tra1 region were assayed for mobilization in the presence of the wild-type prs01 element in trans. the prs01 orit was localized to a 446-nucleotide segment in the intergenic region between open reading frames ltrd and ltre. sequence analysis of this region revealed a cluster of direct and inver ...	1998	9546191
a two-step mechanism for recruitment of pip by pu.1.	transcription of the ig kappa light chain gene is controlled in part by the 3' kappa enhancer. two of the proteins that bind to the 3' enhancer, pu.1 and pip, show tissue-restricted expression and may be responsible for the tissue specificity of 3' enhancer activity. pu.1 alone can bind to dna; however, pip cannot bind to its 3' enhancer site in electrophoretic mobility shift assays, unless recruited by pu.1. previously, we showed that the pu.1 pest domain (rich in the amino acids proline, gluta ...	1998	9551977
a new theta-type thermosensitive replicon from lactococcus lactis as an integration vector for enterococcus faecalis.	we isolated a replication thermosensitive mutant of the theta-type lactococcal pucl22 replicon. an improved version of this thermosensitive replicon was obtained by fusioning the replication repa gene with the downstream repb gene. the resulting plasmid was named pucb3522ts. it is highly instable at 42 degrees c in enterococcus faecalis. integration into the chromosome via homologous recombination was monitored using the npr gene of e. faecalis jh2-2 as a target. a 513 bp pcr amplification produ ...	1998	9561737
molecular ecology and evolution of streptococcus thermophilus bacteriophages--a review.	bacteriophages attacking streptococcus thermophilus, a lactic acid bacterium used in milk fermentation, are a threat to the dairy industry. these small isometric-headed phages possess double-stranded dna genomes of 31 to 45 kb. yoghurt-derived phages exhibit a limited degree of variability, as defined by restriction pattern and host range, while a large diversity of phage types have been isolated from cheese factories. despite this diversity all s. thermophilus phages, virulent and temperate, be ...	1998	9562894
[biological response modifier activity of lactococcus lactis 332].	the biological response modifier (brm) activity of a preparation of heat killed cells of lactococcus lactis 332 which can produce large amount of lactate in culture, was investigated in c3h/he and icr mice. intraperitoneal injection of lactococcus lactis 332 caused an accumulation of neutrophils and macrophages in the peritoneal cavity of the mice, similarly to brms used clinically. as a parameter of the activation of macrophages, the effect of the lactococcus lactis 332 preparation on the produ ...	1998	9564792
reconstruction of the proteolytic pathway for use of beta-casein by lactococcus lactis.	amino acid auxotrophous bacteria such as lactococcus lactis use proteins as a source of amino acids. for this process, they possess a complex proteolytic system to degrade the protein(s) and to transport the degradation products into the cell. we have been able to dissect the various steps of the pathway by deleting one or more genes encoding key enzymes/components of the system and using mass spectrometry to analyse the complex peptide mixtures. this approach revealed in detail how l. lactis li ...	1998	9570397
mechanism of the citrate transporters in carbohydrate and citrate cometabolism in lactococcus and leuconostoc species.	citrate metabolism in the lactic acid bacterium leuconostoc mesenteroides generates an electrochemical proton gradient across the membrane by a secondary mechanism (c. marty-teysset, c. posthuma, j. s. lolkema, p. schmitt, c. divies, and w. n. konings, j. bacteriol. 178:2178-2185, 1996). reports on the energetics of citrate metabolism in the related organism lactococcus lactis are contradictory, and this study was performed to clarify this issue. cloning of the membrane potential-generating citr ...	1998	9572922
a deficiency in aspartate biosynthesis in lactococcus lactis subsp. lactis c2 causes slow milk coagulation.	a mutant of fast milk-coagulating (fmc+) lactococcus lactis subsp. lactis c2, designated l. lactis kb4, was identified. although possessing the known components essential for utilizing casein as a nitrogen source, which include functional proteinase (prtp) activity and oligopeptide, di- and tripeptide, and amino acid transport systems, kb4 exhibited a slow milk coagulation (fmc-) phenotype. when the amino acid requirements of l. lactis c2 were compared with those of kb4 by use of a chemically de ...	1998	9572935
lysis of lactococcus lactis subsp. cremoris sk110 and its nisin-immune transconjugant in relation to flavor development in cheese.	to develop a nisin-producing cheese starter, lactococcus lactis subsp. cremoris sk110 was conjugated with transposon tn5276-ni, which codes for nisin immunity but not for nisin production. cheese made with transconjugant sk110::tn5276-ni as the starter was bitter. the muropeptide of the transconjugant contained a significantly greater amount of tetrapeptides than the muropeptide of strain sk110, which could have decreased the susceptibility of the cells to lysis and thereby the release of intrac ...	1998	9572979
inhibitory activity of a nisin-producing starter culture on listeria innocua in raw ewes milk manchego cheese.	the inhibitory activity of nisin-producing lactococcus lactis subsp. lactis esi 515 on the survival of listeria innocua during ripening of raw ewes milk manchego cheese was investigated. after 60 days of ripening, counts of l. innocua in cheese were 4.08 log units lower than the control when lc. lactis subsp. lactis esi 515 was used as a single-strain starter. nisin activity was detected in cheeses manufactured with lc. lactis subsp. lactis esi 515 throughout the ripening period.	1998	9580244
combinational variation of restriction modification specificities in lactococcus lactis.	three genes coding for a type i r-m system related to the class c enzymes have been identified on the chromosome of lactococcus lactis strain il1403. in addition, plasmids were found that encode only the hsds subunit that directs r-m specificity. the presence of these plasmids in il1403 conferred a new r-m phenotype on the host, indicating that the plasmid-encoded hsds is able to interact with the chromosomally encoded hsdr and hsdm subunits. such combinational variation of type i r-m systems ma ...	1998	9593305
a pcr fingerprinting technique to distinguish isolates of lactococcus lactis.	a fingerprinting technique similar to repetitive extragenic palindromic pcr was developed to identify strains of lactococcus lactis. the method distinguishes closely related strains and discriminates among some with identical ldh sequences. the fingerprinting primer ll-rep1 complements a moderately repeated sequence found in low g + c gram-positive bacteria and may therefore prove useful for discriminating among strains of other low g + c gram-positive species.	1998	9595670
structure of a genome region of the lactobacillus gasseri temperate phage phiadh covering a repressor gene and cognate promoters.	by sequencing the dna regions which flank the intg gene encoding integrase of the temperate lactobacillus (lb.) gasseri bacteriophage phiadh, a continuous sequence of 6590 bp was established. it encompasses five newly identified orfs, of which four are located upstream, and one (orfc) downstream of intg. proteins corresponding to the expected products of the intg upstream coding regions, orfa (33 kda), orf2 (14 kda), rad (12.1 kda), and tec (7.9 kda), were identified by in vitro expression of su ...	1998	9599081
the contribution of caseins to the amino acid supply for lactococcus lactis depends on the type of cell envelope proteinase.	the ability of caseins to fulfill the amino acid requirements of lactococcus lactis for growth was studied as a function of the type of cell envelope proteinase (pi versus piii type). two genetically engineered strains of l. lactis that differed only in the type of proteinase were grown in chemically defined media containing alphas1-, beta-, and kappa-caseins (alone or in combination) as the sources of amino acids. casein utilization resulted in limitation of the growth rate, and the extent of t ...	1998	9603805
influence of reduced water activity on lactose metabolism by lactococcus lactis subsp. cremoris at different ph values	the influence of reduced water activity (aw) on lactose metabolism by lactococcus lactis subsp. cremoris 2254 and 2272 was studied at different ph values. in control incubations (aw, 0.99) with nongrowing cells in ph-controlled phosphate buffer, the levels of carbon recovered as l-(+)-lactate were 92% at ph 6.1 and 5.3 and 78% at ph 4.5. however, the levels of recovery decreased to approximately 50% at all ph values tested when the aw was 0.88 (with glycerol as the humectant). when growing cells ...	1998	9603822
evaluation of lacticin 3147 and a teat seal containing this bacteriocin for inhibition of mastitis pathogens.	lacticin 3147 is a broad-spectrum bacteriocin produced by lactococcus lactis subsp. lactis dpc3147 which is bactericidal against a range of mastitis-causing streptococci and staphylococci. in this study, both lacticin 3147 and the lantibiotic nisin were separately incorporated into an intramammary teat seal product. the seal containing lacticin 3147 exhibited excellent antimicrobial activity and might form the basis of an improved treatment for the prevention of mastitis in dry cows.	1998	9603853
identification of a sodium chloride-regulated promoter in lactococcus lactis by single-copy chromosomal fusion with a reporter gene.	an integration vector, pori13, was developed to screen in lactococcus lactis for expression signals induced by changes in the environment and to assay transcriptional activity of genes in single copy. the plasmid carries a promoterless escherichia coli lacz gene preceded by a start codon, a lactococcal ribosome binding site, and a multiple cloning site. chromosomal sau3ai fragments of l. lactis mg1363 dna were cloned in pori13 using a repa+ e. coli as host. the resulting bank of plasmids was use ...	1998	9604892
physical map of the genome of oenococcus oeni psu-1 and localization of genetic markers.	a physical map of the chromosome of oenococcus oeni psu-1 was constructed. this represents the first map for a strain of this species. a total of 37 restriction sites for the rare-cutting endonucleases ascl, fsel, notl and sfil were mapped on the chromosome, which was found to be circular with an estimated size of 1857 kb. fragment order was determined using several approaches: analysis of partial and double digestions, two-dimensional pulsed-field gel electrophoresis, isolation of linking clone ...	1998	9611789
rna processing is involved in the post-transcriptional control of the citqrp operon from lactococcus lactis biovar diacetylactis.	the importance of lactococcus lactis biovar diacetylactis (l. diacetylactis) in the dairy industry is due to its ability to produce aroma compounds, such as acetoin and diacetyl, from citrate. the first step in citrate utilization is its uptake by the cells. in l. diacetylactis, the citrate transport system is encoded by the citqrp operon. we have previously proposed that expression of citqrp operon is regulated at the post-transcriptional level. in this paper, we show that the cit mrna is proce ...	1998	9613567
construction of a food-grade multiple-copy integration system for lactococcus lactis.	a food-grade vector system was developed that allows stable integration of multiple plasmid copies in the chromosome of lactococcus lactis. the vector consists of the plus origin of replication (ori+) of the lactococcal plasmid pwv01, the sucrose genes of the lactic acid bacterium pediococcus pentosaceus ppe1.0 as selectable marker, a multiple-cloning site, and a lactococcal dna fragment of a well-characterized chromosomal region. the system includes two l. lactis strains, ll108 and ll302, which ...	1998	9615484
cloning of the lactococcus lactis adhe gene, encoding a multifunctional alcohol dehydrogenase, by complementation of a fermentative mutant of escherichia coli.	the lactococcus lactis adhe gene, which encodes a multifunctional alcohol dehydrogenase, has been cloned and characterized. a dna fragment encoding the putative alcohol dehydrogenase domain of the adhe protein was cloned by screening an l. lactis genomic library in a fermentative mutant of escherichia coli and selecting for the ability to grow anaerobically. further analysis of the clone obtained allowed the cloning of the entire adhe gene sequence. analysis of adhe expression in l. lactis durin ...	1998	9620952
multiple transcriptional control of the lactococcus lactis trp operon.	the lactococcus lactis trpegdcfba operon is preceded by a noncoding leader region. transcriptional studies of the trp operon revealed three transcripts with respective sizes of 8 kb (encompassing the entire operon), 290 bases, and 160 bases (corresponding to parts of the leader region). these transcripts most likely result from initiation at the unique ptrp promoter, transcription termination at either t1 (upstream of the trp operon) or t2 (downstream of the trp operon), and/or processing. three ...	1998	9620968
characterization of llaci, a new restriction-modification system from lactococcus lactis subsp. cremoris w15.	the genes encoding the restriction-modification (r/m) system llaci have been found on the naturally occurring 7.0 kb plasmid paw153 in l. lactis subsp. cremoris w15. the r/m system was isolated on a chloramphenicol resistant derivative of the wild type plasmid (paw153cat). plasmid paw153cat and a 2.4 kb hincii-sphi fragment cloned into a high- and a low-copy vector conferred decreased sensitivity in l. lactis lm2301 and l. lactis smq86 against small isometric-headed phages of the 936 or p335 spe ...	1998	9628336
production of fermented milk using a malty compound-producing strain of lactococcus lactis subsp. lactis biovar. diacetylactis, isolated from zimbabwean naturally fermented milk.	malty compound-producing lactococcus lactis subsp. lactis biovar. diacetylactis strain inf-dm1, originally isolated from naturally fermented milk in zimbabwe was used to prepare fermented milk from ordinary milk, milk enriched with 2.5% (w/v) skimmed milk powder and by 2.5% (w/v) increase in dry matter by ultrafiltration. inoculated milk was incubated at 22, 30 and 37 degrees c. analyses were made after 0, 9, 18 and 24 h incubation and also after 24 h incubation followed by storage for one week ...	1998	9631339
determination of the recognition sequence of the type ii restriction endonuclease, llaci, from lactococcus lactis w15.	a new type ii restriction endonuclease, called llaci, was partially purified from lactococcus lactis subsp. cremoris w15. the characterisation of the llaci endonuclease showed it to be an isoschizomer of hindiii, recognising the sequence 5-'a decreases agctt-3'. the cleavage site is indicated by the arrow.	1998	9631541
mucosal delivery of murine interleukin-2 (il-2) and il-6 by recombinant strains of lactococcus lactis coexpressing antigen and cytokine.	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 intr ...	1998	9632584
using specific polyclonal antibodies to study the malolactic enzyme from leuconostoc oenos and other lactic acid bacteria.	specific polyclonal antibodies directed against the malolactic enzyme of leuconostoc oenos were obtained. despite the homologies between the malolactic enzymes from leuc. oenos and lactococcus lactis, no immunological relationship was detected with the l. lactis malolactic enzyme, suggesting differences in their structural organization. the use of the antiserum also demonstrated that the problem of heterologous expression occurring in the recombinant escherichia coli strain (labarre et al. 1996a ...	1998	9633096
detection and characterization of a bacteriocin produced by lactococcus lactis subsp. cremoris r isolated from radish.	bacteria isolated from radish were identified as lactococcus lactis subsp. cremoris r and their bacteriocin was designated lactococcin r. lactococcin r was sensitive to some proteolytic enzymes (proteinase-k, pronase-e, proteases, pepsin, alpha-chymotrypsin) but was resistant to trypsin, papain, catalase, lysozyme and lipase, organic solvents, or heating at 90 degrees c for 15, 30 and 60 min, or 121 degrees c for 15 min. lactococcin r remained active after storage at -20 and -70 degrees c for 3 ...	1998	9633097
immunodot detection of nisin z in milk and whey using enhanced chemiluminescence.	a highly specific antisera was produced in new zealand white rabbits against nisin z, a 3400 da bacteriocin produced by lactococcus lactis ssp. lactis biovar. diacetylactis ul 719. a dot immunoblot assay was then developed to detect nisin z in milk and whey. as few as 1.5 10(-1) international units per ml (iu ml-1), corresponding to 0.003 microgram ml-1 of pure nisin z, were detected in carbonate-bicarbonate buffer within 6 h using chemiluminescence. when milk and whey samples were tested, appro ...	1998	9633631
heterogeneity of plant-associated streptococci as characterized by phenotypic features and restriction analysis of pcr-amplified 16s rdna.	thirty-five strains of streptococci isolated from forage grasses were examined by restriction analysis of pcr-amplified 16s rdna. using a set of seven endonucleases, five 16s rdna genotypes were obtained. the isolates could be identified as belonging to the species enterococcus faecium, ent. mundtii, ent. faecalis, ent. casseliflavus and lactococcus lactis ssp. lactis, respectively. to assign the isolates to one of these species, digestion with the endonuclease hinfi was sufficient. data obtaine ...	1998	9633643
mechanistic properties of the two-component bacteriocin lactococcin g.	lactococcin g is a bacteriocin whose activity depends on the complementary action of two peptides, termed alpha and beta. biologically active, synthetic lactococcin g was used to study the mode of action on sensitive cells of lactococcus lactis. the alpha and beta peptides can bind independently to the target cell surface, but activity requires the complementary peptide. once bound to the cell surface, the peptides cannot be displaced to the surfaces of other cells. a complex of alpha and beta p ...	1998	9422598