Publications
| Title | Abstract | Year(sorted ascending) Filter | PMID Filter |
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| stereoselectivity of the membrane potential-generating citrate and malate transporters of lactic acid bacteria. | the citrate transporter of leuconostoc mesenteroides (citp) and the malate transporter of lactococcus lactis (mlep) are homologous proteins that catalyze citrate-lactate and malate-lactate exchange, respectively. both transporters transport a range of substrates that contain the 2-hydroxycarboxylate motif, ho-cr(2)-coo(-) [bandell, m., et al. (1997) j. biol. chem. 272, 18140-18146]. in this study, we have analyzed binding and translocation properties of citp and mlep for a wide variety of substr ... | 1999 | 10441129 |
| an improved method for screening alpha-acetolactate producing mutants. | alpha-acetolactate-deficient lactococcus lactis ssp. lactis biovar. diacelylactis are utilised in several industrial processes for producing diacetyl and alpha-acetolactate. they can be selected by screening after random mutagenesis. we improved a previously described screening method [monnet, c., schmitt, p., diviès, c., 1997. appl. environ. microbiol. 63, 793-795], which makes it possible to screen up to 1000 colonies per agar plate, whereas the previous method allowed to screen only 60 coloni ... | 1999 | 10445317 |
| primary structure and features of the genome of the lactobacillus gasseri temperate bacteriophage (phi)adh. | the complete dna sequence of the lactobacillus (lb.) gasseri temperate phage (phi)adh was determined. the linear and double-stranded genome consists of 43.785bp with a g+c content of 35. 3% and 3' protruding cohesive ends of 12nt. sixty-two possible orfs were identified. on the basis of homology comparisons, some of them could be assigned to possible functions, such as a helicase, a nucleic acid polymerase and a protease. in a non-coding area of the (phi)adh genome, structural features of a pote ... | 1999 | 10452953 |
| identification and characterization of two bacteriocin-producing bacteria isolated from garlic and ginger root. | two bacteriocin-producing bacterial strains were isolated from garlic and ginger root by the agar overlay method. the bacteria were identified by 16s rrna sequence analyses and fermentation patterns as leuconostoc mesenteroides (garlic isolate) and lactococcus lactis (ginger isolate). the bacteriocins were assigned the names leucocin bc2 and lactocin gi3, respectively. physiochemical properties and antimicrobial spectra of the bacteriocins were determined by the spot-on-lawn method. both bacteri ... | 1999 | 10456744 |
| effect of heat shock or cold shock treatment on the resistance of lactococcus lactis to freezing and lyophilization | this study investigated the effect of heat shock or cold shock treatment on the resistance of commercial lactococcus lactis ssp. lactis and l. lactis ssp. cremoris cheese starter bacteria to freezing and freeze-drying. the ability to withstand freezing at -60 degrees c for 24 h was variable among lactococci, but could be significantly (p < 0.05) improved in most strains by a 25-min heat shock at 42 degrees c (l. lactis ssp. lactis) or 39 degrees c (l. lactis ssp. cremoris) or by a 2-h cold shock ... | 1999 | 10458904 |
| acetate utilization in lactococcus lactis deficient in lactate dehydrogenase: a rescue pathway for maintaining redox balance. | acetate was shown to improve glucose fermentation in lactococcus lactis deficient in lactate dehydrogenase. 13c and 1h nuclear magnetic resonance studies using [2-13c]glucose and [2-(13)c]acetate as substrates demonstrated that acetate was exclusively converted to ethanol. this novel pathway provides an alternative route for nad+ regeneration in the absence of lactate dehydrogenase. | 1999 | 10464231 |
| endoglucanase v and a phosphatase from trichoderma viride are able to act on modified exopolysaccharide from lactococcus lactis subsp. cremoris b40. | eps b40 from lactococcus lactis subsp. cremoris consists of a repeating unit of-->4)-beta-d-glcp-(1-->4)-[alpha-l-rhap-(1 -->2)][alpha-d-galp-1-po4-3]-beta-d-galp-(1-->4)-beta-d-glcp-(1-->. a phosphatase from trichoderma viride was able to release phosphate, but only after removal of rhamnosyl and galactosyl residues by mild cf3co2h treatment. purified endov from t. viride was able to act on the backbone of the polymer, but only if rhamnosyl substituents and phosphate had been removed. after com ... | 1999 | 10466211 |
| d-lactate dehydrogenase gene (ldhd) inactivation and resulting metabolic effects in the lactobacillus johnsonii strains la1 and n312. | lactobacillus johnsonii la1, a probiotic bacterium with demonstrated health effects, grows in milk, where it ferments lactose to d- and l-lactate in a 60:40% ratio. the d-lactate dehydrogenase (d-ldh) gene (ldhd) of this strain was isolated, and an in vitro-truncated copy of that gene was used to inactivate the genomic copy in two strains, la1 and n312, by gene replacement. for that, an 8-bp deletion was generated within the cloned ldhd gene to inactivate its function. the plasmid containing the ... | 1999 | 10473408 |
| identification of a virulence-associated protein homolog gene and isra1 in a plasmid of riemerella anatipestifer. | riemerella anatipestifer is the causative agent of polyserositis of ducks and geese. we have previously reported that a 3.9-kb plasmid, pcfc1, carries protein genes (vapd1 and vapd2) that are similar to virulence-associated genes of other bacteria. in the present study, we report the complete sequence of a second plasmid of 5.6 kb, pcfc2. pcfc2 has a 28% g-c content and three large open reading frames (orfs). one of the orfs (designated asvapd1) encodes a polypeptide that shares 53.9, 53.9, 48.3 ... | 1999 | 10481080 |
| a reverse transcriptase/maturase promotes splicing by binding at its own coding segment in a group ii intron rna. | group ii introns encode reverse transcriptases that promote rna splicing (maturase activity) and then with the excised intron form a dna endonuclease that mediates intron mobility by target dna-primed reverse transcription (tprt). here, we show that the primary binding site for the maturase (ltra) encoded by the lactococcus lactis ll.ltrb intron is within a region of intron domain iv that includes the start codon of the ltra orf. this binding is enhanced by other elements, particularly domain i ... | 1999 | 10488339 |
| cloning and expression of the pediocin operon in streptococcus thermophilus and other lactic fermentation bacteria. | production of pediocin in pediococcus acidilactici is associated with pmbr1.0, which encodes prepediocin, a pediocin immunity protein, and two proteins involved in secretion and precursor processing. these four genes are organized as an operon under control of a single promoter. we have constructed shuttle vectors that contain all four structural genes, the chromosomal promoter st(p2201) from streptococcus thermophilus, and repa from the 2-kbp s. thermophilus plasmid per8. the recombinant plasmi ... | 1999 | 10489440 |
| development of a lacticin 3147-enriched whey powder with inhibitory activity against foodborne pathogens. | the broad-spectrum bacteriocin lacticin 3147, produced by lactococcus lactis dpc3147, is inhibitory to a wide range of gram-positive food spoilage and pathogenic organisms. a 10% solution of demineralized whey powder was fermented with dpc3147 at a constant ph of 6.5. the fermentate was spray dried, and the resulting powder exhibited inhibitory activity. the ability of the lacticin 3147-enriched powder to inhibit listeria monocytogenes scott a and staphylococcus aureus 10 was assessed in buffer ... | 1999 | 10492475 |
| cold shock proteins and low-temperature response of streptococcus thermophilus cnrz302. | low-temperature adaptation and cryoprotection were studied in the thermophilic lactic acid bacterium streptococcus thermophilus cnrz302. s. thermophilus actively adapts to freezing during a pretreatment at 20 degrees c, resulting in an approximately 1, 000-fold increased survival after four freeze-thaw cycles compared to mid-exponential-phase cells grown at an optimal temperature of 42 degrees c. no adaptation is observed when cells are exposed to a temperature (10 degrees c) below the minimal g ... | 1999 | 10508072 |
| enhanced production of pediocin pa-1 and coproduction of nisin and pediocin pa-1 by lactococcus lactis. | the production and secretion of class ii bacteriocins share a number of features that allow the interchange of genetic determinants between certain members of this group of antimicrobial peptides. lactococcus lactis il1403 encodes translocatory functions able to recognize and mediate secretion of lactococcin a. the ability of this strain to also produce the pediococcal bacteriocin pediocin pa-1, has been demonstrated previously by the introduction of a chimeric gene, composed of sequences encodi ... | 1999 | 10508073 |
| metabolic engineering of lactic acid bacteria: overview of the approaches and results of pathway rerouting involved in food fermentations. | lactic acid bacteria such as lactococcus lactis are the microorganisms of choice for performing metabolic engineering in relation to food fermentation. these bacteria are used extensively in food fermentations, they have a simple and therefore controllable metabolism and the molecular genetics of these food bacteria is well-developed. there have been recent successes in metabolic engineering in these lactic acid bacteria, including examples of changes in both primary metabolism (diacetyl and ala ... | 1999 | 10508636 |
| concentration and shear-rate dependence of the viscosity of an exocellular polysaccharide | the viscosity of an exocellular polysaccharide (eps) produced by the bacterium lactococcus lactis subsp. cremoris b40 was studied in aqueous solution at an ionic strength of 0.10m. first, the zero-shear viscosity was determined as a function of the concentration. from the data in the low concentration range, the intrinsic viscosity was determined. in addition, the shear-thinning behavior was measured at several concentrations. by combining existing theories, a new equation is proposed that descr ... | 1999 | 10508966 |
| production of menaquinones by lactic acid bacteria. | lactic acid bacteria were examined for their ability to produce quinone compounds, which may include dietary sources of menaquinones. isoprenyl quinones in bacterial cells grown in a synthetic medium were extracted and analyzed by thin layer chromatography. lactococcus lactis ssp. cremoris (three strains), lactococcus lactis ssp. lactis (two strains), and leuconostoc lactis were selected as high producers of quinone that synthesized more than 230 nmol of quinones/g of dried cells. the quinones w ... | 1999 | 10509247 |
| genetic and biochemical characterization of a high-affinity betaine uptake system (busa) in lactococcus lactis reveals a new functional organization within bacterial abc transporters. | the cytoplasmic accumulation of exogenous betaine stimulates the growth of lactococcus lactis cultivated under hyperosmotic conditions. we report that l. lactis possesses a single betaine transport system that belongs to the atp-binding cassette (abc) superfamily of transporters. through transposon mutagenesis, a mutant deficient in betaine transport was isolated. we identified two genes, busaa and busab, grouped in an operon, busa (betaine uptake system). the transcription of busa is strongly r ... | 1999 | 10515910 |
| functional analysis of glycosyltransferase genes from lactococcus lactis and other gram-positive cocci: complementation, expression, and diversity. | sixteen exopolysaccharide (eps)-producing lactococcus lactis strains were analyzed for the chemical compositions of their epss and the locations, sequences, and organization of the eps genes involved in eps biosynthesis. this allowed the grouping of these strains into three major groups, representatives of which were studied in detail. previously, we have characterized the eps gene cluster of strain nizo b40 (group i) and determined the function of three of its glycosyltransferase (gtf) genes. f ... | 1999 | 10515924 |
| pyruvate flux distribution in nadh-oxidase-overproducing lactococcus lactis strain as a function of culture conditions. | the influence of growth conditions on product formation from glucose by lactococcus lactis strain nz9800 engineered for nadh-oxidase overproduction was examined. in aerobic batch cultures, a large production of acetoin and diacetyl was found at acidic ph under ph-unregulated conditions. however, pyruvate flux was mainly driven towards lactate production when these cells were grown under strictly ph-controlled conditions. a decreased nadh-oxidase overproduction accompanied the homolactic fermenta ... | 1999 | 10518751 |
| amplification of fluorescently labelled dna within gram-positive and acid-fast bacteria. | representative organisms from a variety of gram-positive genera were subjected to varying regimes in order to optimise the intracellular amplification of dna. the bacteria were subjected to treatments with paraformaldehyde, muramidases and mild acid hydrolysis to discover which regime made each organism permeable to the amplification reagents yet allowed retention of the fluorescein-labelled amplified products within the cell. scanning electron micrographs were used to corroborate the effectiven ... | 1999 | 10520585 |
| 6-phosphogluconate dehydrogenase from lactococcus lactis: a role for arginine residues in binding substrate and coenzyme. | a gene encoding 6-phosphogluconate dehydrogenase (6-pgdh, ec 1.1.1. 44) was identified from the homofermentative lactic acid bacterium lactococcus lactis, by complementation of escherichia coli mutants. the cloned gene was then expressed to high levels in e. coli and the protein purified for kinetic analysis. the enzyme had a km for 6-phosphogluconate of 15.4+/-1.4 microm and for nadp of 1.9+/-0.2 microm at ph 7.5. sequence comparison of the l. lactis 6-pgdh with the corresponding enzyme derived ... | 1999 | 9931298 |
| clpp participates in the degradation of misfolded protein in lactococcus lactis. | clpp proteins constitute a family of homologous proteins found in both prokaryotic and eukaryotic organisms. in escherichia coli, clpp is the proteolytic component of a large complex also containing either the clpa or the clpx atpases. we show here that the clpp gene from the gram-positive bacterium lactococcus lactis encodes a 22-kda protein that is induced by low ph and by the t-rna analogue puromycin, which interferes with translation, resulting in the production of misfolded puromycyl-contai ... | 1999 | 9987112 |
| ctsr, a novel regulator of stress and heat shock response, controls clp and molecular chaperone gene expression in gram-positive bacteria. | clpp and clpc of bacillus subtillis encode subunits of the clp atp-dependent protease and are required for stress survival, including growth at high temperature. they play essential roles in stationary phase adaptive responses such as the competence and sporulation developmental pathways, and belong to the so-called class iii group of heat shock genes, whose mode of regulation is unknown and whose expression is induced by heat shock or general stress conditions. the product of ctsr, the first ge ... | 1999 | 9987115 |
| digoxigenin-labeled probe for rapid identification of nisinogenic lactococcus lactis strains. | from the nisz gene sequence, a non-radioactive digoxigenin-labeled dna probe, was tested for detection of nisin-producing strains using polymerase chain reaction amplification. the digoxigenin-labeled dna probe clearly discriminated between nisin-producing and non-producing strains with a high degree of sensitivity and specificity. by agarose gel electrophoresis, 1.4 ng of nisin dna was detected using the digoxigenin-labeled dna probe compared with 11 ng using direct polymerase chain reaction am ... | 1999 | 9987840 |
| differentiation of lactococcus lactis subspecies lactis and subspecies cremoris strains by their adaptive response to stresses. | lactococcus lactis subspecies lactis (l. lactis ssp. lactis) and lactococcus lactis subspecies cremoris (l. lactis ssp. cremoris) were investigated in respect to their response to acid, bile-salt and freezing stresses. first, the sublethal and lethal levels of each stress were determined for both subspecies. for acid stress, the levels were ph 4.5 and 2.5, respectively, for l. lactis ssp. lactis, and ph 5.0 and 3.0, respectively, for l. lactis ssp. cremoris. for bile-salt stress, the levels were ... | 1999 | 9987842 |
| genetic organization and functional analysis of a novel phage abortive infection system, abil, from lactococcus lactis. | a plasmid-encoded phage abortive infection mechanism (abil) was identified from lactococcus lactis biovar. diacetylactis ld10-1. abil conferred complete resistance to the small isometric-headed phage phi 712 (936 species) and partial resistance to the prolate-headed phage phi c2 (c2 species) when introduced into l. lactis lm0230. however, abil was not effective against the small isometric-headed phage ul36 (p335 species). the abil determinant was sequenced and it consists of two open reading fra ... | 1999 | 9990732 |
| influence of carbohydrate starvation and arginine on culturability and amino acid utilization of lactococcus lactis subsp. lactis. | two strains of lactococcus lactis subsp. lactis were used to determine the influence of lactose and arginine on viability and amino acid use during carbohydrate starvation. lactose provided energy for logarithmic-phase growth, and amino acids such as arginine provided energy after carbohydrate exhaustion. survival time, cell numbers, and atp concentrations increased with the addition of arginine to the basal medium. by the onset of lactose exhaustion, the concentrations of glycine-valine and glu ... | 1999 | 9925598 |
| llafi, a type iii restriction and modification system in lactococcus lactis. | we describe a type iii restriction and modification (r/m) system, llafi, in lactococcus lactis. llafi is encoded by a 12-kb native plasmid, pnd801, harbored in l. lactis ll42-1. sequencing revealed two adjacent open reading frames (orfs). one orf encodes a 680-amino-acid polypeptide, and this orf is followed by a second orf which encodes an 873-amino-acid polypeptide. the two orfs appear to be organized in an operon. a homology search revealed that the two orfs exhibited significant similarity t ... | 1999 | 9925601 |
| use of the integration elements encoded by the temperate lactococcal bacteriophage tp901-1 to obtain chromosomal single-copy transcriptional fusions in lactococcus lactis. | previously we showed that only one phage-expressed protein (orf1), a 425-bp region upstream of the orf1 gene (presumably encoding a promoter), and the attp region are necessary and also sufficient for integration of the bacteriophage tp901-1 genome into the chromosome of lactococcus lactis subsp. cremoris (b. christiansen, l. brondsted, f. k. vogensen, and k. hammer, j. bacteriol. 178:5164-5173, 1996). in this work, a further analysis of the phage-encoded elements involved in integration was per ... | 1999 | 9925612 |
| mobile introns: retrohoming by complete reverse splicing. | a mobile bacterial group ii intron can integrate into dna by the reverse splicing into a target site of its rna transcript, which then acts as a template for dna synthesis by an encoded reverse transcriptase. mobility does not require homologous recombination, which has important practical and evolutionary implications. | 1999 | 9889113 |
| restrictive use of detergents in the functional reconstitution of the secondary multidrug transporter lmrp. | the histidine-tagged secondary multidrug transporter lmrp was overexpressed in lactococcus lactis, using a novel protein expression system for cytotoxic proteins based on the tightly regulated, nisin-inducible nisa promoter. lmrp-mediated h+/drug antiport activity in inside-out membrane vesicles was inhibited by detergents, such as triton x-100, triton x-114, and tween 80, at low concentrations that did not affect the magnitude or composition of the proton motive force. the inhibition of the act ... | 1999 | 9893996 |
| nisin independent induction of the nisa promoter in lactococcus lactis during growth in lactose or galactose. | nisin biosynthesis is autoregulated extracellularly by the mature and modified peptide. to investigate other regulatory effects on nisin biosynthesis, a transcription fusion of the nisa promoter from lactococcus lactis atcc 11454 to the promoterless lacz gene from streptococcus thermophilus was constructed. this fusion construct, pdoc99, expressed beta-galactosidase in l. lactis atcc 11454 growing in m17 medium containing glucose (m17g). consistent with the known model for transcription of nisa, ... | 1999 | 9919668 |
| molecular characterization of the lactococcus lactis ptshi operon and analysis of the regulatory role of hpr. | the lactococcus lactis ptsh and ptsi genes, encoding the general proteins of the phosphoenolpyruvate-dependent phosphotransferase system, hpr and enzyme i, respectively, were cloned, and the regulatory role of hpr was studied by mutational analysis of its gene. a promoter sequence was identified upstream of the ptshi operon, and the transcription start site was mapped by primer extension. the results of northern analyses showed the presence of two glucose-inducible transcripts, one of 0.3 kb con ... | 1999 | 9922238 |
| novel characteristic for distinguishing lactococcus lactis subsp. lactis from subsp. cremoris. | lactococcus lactis strains were examined for their ability to produce gamma-aminobutyric acid (gaba). results showed that strains of l. lactis subsp. lactis were able to produce this acid, whereas l. lactis subsp. cremoris were not. gaba production thus represents another effective characteristic for distinguishing l. lactis subsp. lactis from l. lactis subsp. cremoris. | 1999 | 10028257 |
| effects of metabolic flux on stress response pathways in lactococcus lactis. | studies of cellular responses to stress conditions such as heat, oxygen or starvation have revealed the existence of numerous specific or interactive response pathways. we previously observed in lactococcus lactis that inactivation of the reca gene renders the lactococcal strain sensitive not only to dna-damaging agents but also to oxygen and heat. to further examine the stress response pathways in l. lactis, we isolated thermoresistant insertional mutants (trm) of the reca strain. eighteen inde ... | 1999 | 10048028 |
| mechanism of citrate metabolism in lactococcus lactis: resistance against lactate toxicity at low ph. | measurement of the flux through the citrate fermentation pathway in resting cells of lactococcus lactis crl264 grown in a ph-controlled fermentor at different ph values showed that the pathway was constitutively expressed, but its activity was significantly enhanced at low ph. the flux through the citrate-degrading pathway correlated with the magnitude of the membrane potential and ph gradient that were generated when citrate was added to the cells. the citrate degradation rate and proton motive ... | 1999 | 10049375 |
| a general method for selection of alpha-acetolactate decarboxylase-deficient lactococcus lactis mutants to improve diacetyl formation. | the enzyme acetolactate decarboxylase (ald) plays a key role in the regulation of the alpha-acetolactate pool in both pyruvate catabolism and the biosynthesis of the branched-chain amino acids, isoleucine, leucine, and valine (ilv). this dual role of ald, due to allosteric activation by leucine, was used as a strategy for the isolation of ald-deficient mutants of lactococcus lactis subsp. lactis biovar diacetylactis. such mutants can be selected as leucine-resistant mutants in ilv- or iv-prototr ... | 1999 | 10049884 |
| inhibition of listeria monocytogenes in cottage cheese manufactured with a lacticin 3147-producing starter culture. | the efficacy of using a lacticin 3147-producing starter as a protective culture to improve the safety of cottage cheese was investigated. this involved the manufacture of cottage cheese using lactococcus lactis dpc4268 (control) and l. lactis dpc4275, a bacteriocin-producing transconjugant strain derived from dpc4268. a number of listeria monocytogenes strains, including a number of industrial isolates, were assayed for their sensitivity to lacticin 3147. these strains varied considerably with r ... | 1999 | 10063625 |
| the effect of lactose derivatives on intestinal lactic acid bacteria. | nine strains of lactic acid bacteria were studied for growth and fermentation end products on lactulose, lactitol, and lactobionic acid. in addition, human fecal and biopsy isolates were screened for new potential by probiotic strains utilizing lactose derivatives, and one new isolate of lactobacillus rhamnosus was enriched. the utilization of lactose derivatives and the effect on the fermentation end products were dependent on strain. typical mixed-acid fermentations were observed with lb. rham ... | 1999 | 10068946 |
| isolation and physical characterization of an exocellular polysaccharide. | the physical properties of a polysaccharide produced by the lactic acid bacterium lactococcus lactis subsp. cremoris strain nizo b40 were investigated. separation of the polysaccharide from most low molar mass compounds in the culture broth was performed by filtration processes. residual proteins and peptides were removed by washing with a mixture of formic acid, ethanol, and water. gel permeation chromatography (gpc) was used to size fractionate the polysaccharide. fractions were analyzed by mu ... | 1999 | 10070259 |
| isolation and characterization of a purc(orf)qlf operon from lactococcus [correction of lactobacillus] lactis mg1614. | we have isolated genes encoding enzymes of the de novo purine nucleotide biosynthesis pathway from lactococcus lactis mg1614 by colony hybridization using dig-labeled dna probes. the organization of the genes needed for the de novo biosynthesis of purine nucleotides in l. lactis differs from that found in other organisms. in l. lactis there is a gene cluster, which contains five out of the 11 genes needed for the de novo biosynthesis of imp, namely purc, orf, purq, purl and purf. these genes wer ... | 1999 | 10071207 |
| characterization of the divergent sacbk and sacar operons, involved in sucrose utilization by lactococcus lactis. | the divergently transcribed sacbk and sacar operons, which are involved in the utilization of sucrose by lactococcus lactis nz9800, were examined by transcriptional and gene inactivation studies. northern analyses of rna isolated from cells grown at the expense of different carbon sources revealed three sucrose-inducible transcripts: one of 3.2 kb containing sacb and sack, a second of 3.4 kb containing saca and sacr, and a third of 1.8 kb containing only sacr. the inactivation of the sacr gene b ... | 1999 | 10074089 |
| the activity of escherichia coli dihydroorotate dehydrogenase is dependent on a conserved loop identified by sequence homology, mutagenesis, and limited proteolysis. | dihydroorotate dehydrogenase catalyzes the oxidation of dihydroorotate to orotate. the enzyme from escherichia coli was overproduced and characterized in comparison with the dimeric lactococcus lactis a enzyme, whose structure is known. the two enzymes represent two distinct evolutionary families of dihydroorotate dehydrogenases, but sedimentation in sucrose gradients suggests a dimeric structure also of the e. coli enzyme. product inhibition showed that the e. coli enzyme, in contrast to the l. ... | 1999 | 10074342 |
| the expression signals of the lactobacillus brevis slpa gene direct efficient heterologous protein production in lactic acid bacteria. | a cassette based on the expression signals of the lactobacillus brevis surface (s)-layer protein gene (slpa) was constructed. the low-copy-number vector pkth2095, derived from pgk12, was used as the cloning vector. the efficiency of slpa promoters in intracellular protein production was studied using three reporter genes, beta-glucuronidase (gusa), luciferase (luc) and aminopeptidase n (pepn) in three different lactic acid bacteria hosts: lactococcus lactis, lactobacillus plantarum and lactobaci ... | 1999 | 10077822 |
| correlation between polymerase chain reaction analysis of the histidine biosynthesis operon, randomly amplified polymorphic dna analysis and phenotypic characterization of dairy lactococcus isolates. | a collection of 32 lactococcal strains isolated from raw milk in the camembert rdo (registered designation of origin) area were phenotypically and genotypically characterized. as expected for environmental isolates, all strains had a lactococcus lactis subsp. lactis phenotype. the strains were then genotypically identified by the randomly amplified polymorphic dna (rapd) technique, using reference strains of lactococci. two major clusters were identified containing the two subspecies lactis and ... | 1999 | 10077825 |
| membrane topology of the lactococcal bacteriocin atp-binding cassette transporter protein lcnc. involvement of lcnc in lactococcin a maturation. | many non-lantibiotic bacteriocins of lactic acid bacteria are produced as precursors with n-terminal leader peptides different from those present in preproteins exported by the general sec-dependent (type ii) secretion pathway. these bacteriocins utilize a dedicated (type i) secretion system for externalization. the secretion apparatus for the lactococcins a, b, and m/n (lcna, b, and m/n) from lactococcus lactis is composed of the two membrane proteins lcnc and lcnd. lcnc belongs to the atp-bind ... | 1999 | 10085080 |
| regulation of expression of the lactococcus lactis histidine operon. | in lactococcus lactis, the his operon contains all the genes necessary for histidine biosynthesis. it is transcribed from a unique promoter, localized 300 bp upstream of the first gene. the region corresponding to the untranslated 5' end of the transcript, named the his leader region, displays the typical features of the t box transcriptional attenuation mechanism which is involved in the regulation of many amino acid biosynthetic operons and trna synthetase genes in gram-positive bacteria. here ... | 1999 | 10094678 |
| disruption and analysis of the clpb, clpc, and clpe genes in lactococcus lactis: clpe, a new clp family in gram-positive bacteria. | in the genome of the gram-positive bacterium lactococcus lactis mg1363, we have identified three genes (clpc, clpe, and clpb) which encode clp proteins containing two conserved atp binding domains. the proteins encoded by two of the genes belong to the previously described clpb and clpc families. the clpe gene, however, encodes a member of a new clp protein family that is characterized by a short n-terminal domain including a putative zinc binding domain (-cx2cx22cx2c-). expression of the 83-kda ... | 1999 | 10094684 |
| a plasmid-encoded two-component regulatory system involved in copper-inducible transcription in lactococcus lactis. | two regulatory genes (lcor and lcos) were identified from a plasmid-borne lactococcal copper resistance determinant and characterized by transcriptional fusion to the promoterless chloramphenicol acetyltransferase gene (cat). rt-pcr analysis indicates that lcor and lcos are organized within an operon, controlling the transcription of cat in a copper-inducible manner. the amino acid sequences deduced from lcor and lcos show homology to the response and sensor proteins of known two-component regul ... | 1999 | 10095123 |
| hydrolysis of alphas1- and beta-casein-derived peptides with a broad specificity aminopeptidase and proline specific aminopeptidases from lactococcus lactis subsp. cremoris am2. | aminopeptidase hydrolysis of alpha(s)1 - and beta-casein-derived synthetic peptides containing non-consecutive and consecutive proline residues was characterised. aminopeptidase p (pep p) (ec 3.4.11.9) or post-proline dipeptidyl aminopeptidase (ppda) (ec 3.4.14.5) along with lysine-paranitroanilide hydrolase (kpna-h) (ec 3.4.11.1) activities are required in the degradation of peptides containing non-consecutive proline residues. however, both pep p and ppda along with kpna-h are required for hyd ... | 1999 | 10094481 |
| a method for bacteriocin quantification. | different aspects of the most commonly used assay methods in the study of bacteriocins were examined. the conditions under which extraction and incubation (including exposure time) take place were analysed, and several different formal models that are usually employed to calculate id50 were compared. as an alternative designed to overcome the problems which characterize the response of micro-organisms that are sensitive to bacteriocins, an operative procedure in a liquid medium and a modified re ... | 1999 | 10664913 |
| the role of escherichia coli rnase e and rnase iii in the processing of the citqrp operon mrna from lactococcus lactis biovar diacetylactis. | citrate transport in lactococcus lactis biovar diacetylactis (l. diacetylactis) is catalyzed by citrate permease p (citp), which is encoded by the plasmidic citp gene. two partial overlapping open reading frames citq and citr are located upstream of citp. these two genes, together with citp, constitute the citqrpoperon. in this report it was shown that in l. diacetylactis and escherichia coli, cit mrna is subject to the same specific cleavages at a complex secondary structure which includes the ... | 1999 | 10943565 |
| diversity among lactococci isolated from ewes' raw milk and cheese. | the technological and genetic characteristics of lactococci present in ewes' raw milk and 1-d-old ewes' raw milk cheeses sampled over a 1-year period were investigated. the proportion of lactic acid bacteria isolates from milk samples able to decrease milk ph by more than 1.25 units after 6 h incubation at 30 degrees c reached 14.5% in spring vs 10.7% in summer, 8.3% in autumn and 3.0% in winter. in 1-d-old cheese samples, the proportion of lactic acid bacteria able to lower milk ph by more than ... | 1999 | 10692072 |
| characteristics of chi distribution on different bacterial genomes. | the availability of full genome sequences provides the bases for analyzing global properties of the genetic text. for example, oligonucleotide sequences that are over- or underrepresented can be identified by taking into account the overall genome composition and organization. one of the most overrepresented oligonucleotides in escherichia coli is the chi site, an octanucleotide that stimulates dna repair by homologous recombination. here we analyze the genomic distribution of chi in e. coli and ... | 1999 | 10672998 |
| glucose/citrate cometabolism in lactococcus lactis subsp. lactis biovar diacetylactis with impaired alpha-acetolactate decarboxylase. | the pyruvate metabolism of a lactococcus lactis subsp. lactis biovar diacetylactis mutant deficient in alpha-acetolactate decarboxylase and its wild-type strain was studied during batch cultivations. a chemically defined medium was used containing glucose as carbon- and energy-source. the alpha-acetolactate decarboxylase deficiency had no effect on the specific growth rate. addition of citrate was found to increase the specific growth rate of both strains under aerobic and anaerobic conditions. ... | 1999 | 10937822 |
| pyruvate metabolism in lactococcus lactis is dependent upon glyceraldehyde-3-phosphate dehydrogenase activity. | modification of glyceraldehyde-3-phosphate dehydrogenase (gapdh) activity from lactococcus lactis was undertaken during batch fermentation on lactose, by adding various concentrations of iodoacetate (iaa), a compound which specifically inhibits gapdh at low concentrations, to the culture medium. as iaa concentration is increased, gapdh activity diminishes, provoking a decrease of both the glycolytic flux and the specific growth rate. this control exerted at the level of gapdh was due partially t ... | 1999 | 10937934 |
| evaluation of yeast extracts as growth media supplements for lactococci and lactobacilli by using automated spectrophotometry. | an automated spectrophotometric (as) method was used to evaluate the growth-promoting ability of yeast extracts (ye) on cultures of lactobacillus acidophilus and lactococcus lactis subsp. cremoris. the as data were compared to that obtained from classical shake flask fermentations and from 250 ml bioreactors equipped with ph control. in assays involving the evaluation of 26 different commercial ye, maximum growth rate (&mgr;(max)) values determined with the as unit ranged from 0.25 to 0.45 h(-1) ... | 1999 | 12501397 |
| [expression in lactococcus lactis of catalytically active phenylalanine ammonia-lyase from parsley]. | the phenylalanine ammonia-lyase (pal) cdna of parsley (petroselinum crispum) was subcloned into constitutive expression vector pmg36e downstream of the p32 promoter. the resulting plasmid pmg36epal was introduced into lactococcus lactis subsp. lactis mg1363 by electroporation. the recombinant strain showed its pal activity conversing the l-phenylalanine in the culture medium into trans-cinnamic acid. a new secretory vector pxhs was constructed by recombination of pmg36e with a lactococcal usp45 ... | 1999 | 12555534 |
| influence of the oral administration of lactic acid bacteria on iga producing cells associated to bronchus. | intestinal, respiratory and genitourinary mucosal surfaces are the most important routes of entry for microbial pathogens. the stimulus of the mucosal immunity is not easy because the trigger keys for the activation do not follow the ones of the systemic immune response. in previous works we have demonstrated that some lactic acid bacteria (lab), when orally administered, can induce an enhance of the gut immune response. taking into account the concept of a common mucosal response, we studied th ... | 1999 | 12783652 |
| depletion interaction of casein micelles and an exocellular polysaccharide. | casein micelles become mutually attractive when an exocellular polysaccharide produced by lactococcus lactis subsp. cremoris nizo b40 (hereafter called eps) is added to skim milk. the attraction can be explained as a depletion interaction between the casein micelles induced by the nonadsorbing eps. we used three scattering techniques (small-angle neutron scattering, turbidity measurements, and dynamic light scattering) to measure the attraction. in order to connect the theory of depletion intera ... | 1999 | 11969829 |
| [construction of genomic library from l. lactis al2 and isolation of entire nisin biosynthesis gene cluster]. | a total dna library of lactococcus lactis al2 with high yield of nisin was successfully constructed using lambda embl3 as vector. 3900 plaques were obtained, which is much more than the required number of recombinants that represents an entire l. lactis genome according to clarke and carbon formula. southern hybridization, pcr amplification and dna sequencing revealed that the entire nisin biosynthesis gene cluster was isolated from the constructed library. | 2000 | 12548755 |
| [expression and activity analysis of the human glutathione-s-transferase in lactococcus lactis]. | the glutathione-s-transferase a1 cdna was amplified from human liver total rnas by rt-pcr and was cloned into a escherichia coli expression vector pet23b, then the recombinant plasmid pet23bhgst was introduced into e. coli bl21 (de3) and induced by iptg, the high-level expression of hgsta1 appeared in the e. coli cells. the cdna encoding hgsta1 was subcloned into pmg36e, a lactococcal expression vector, and introduced into lactococcus lactis mg1363 by electroporation. in the positive transforman ... | 2000 | 12548934 |
| characterization of opua, a glycine-betaine uptake system of lactococcus lactis. | a lactococcus lactis glycine-betaine transport system was identified by functional complementation of an escherichia coli prop prou mutant with a gene library from l. lactis sbsp. cremoris. the cloned locus forms an operon highly homologous to opua, encoding a glycine-betaine uptake system of bacillus subtilis. disruption of opua in l. lactis abolished protection by glycine-betaine against elevated osmolarity. opua belongs to the so-called "abc transporters" family, which comprise an extracellul ... | 2000 | 10939245 |
| towards a proteomic map of lactococcus lactis ncdo 763. | lactococcus lactis is a widely used bacteria in dairy industry, specially in cheese ripening. numerous lactococcal enzymes and proteins are involved in this process. proteomics makes it possible to deal with a high number of proteins and identify modification of their patterns in two-dimensional (2-d) gels. however, an annotated reference map is necessary prior to analyzing protein variations. we have begun to construct such a map in easily reproducible conditions and identify proteins. | 2000 | 10939470 |
| the membrane-bound h(+)-atpase complex is essential for growth of lactococcus lactis. | the eight genes which encode the (f(1)f(o)) h(+)-atpase in lactococcus lactis subsp. cremoris mg1363 were cloned and sequenced. the genes were organized in an operon with the gene order atpebfhagdc; i.e., the order of atpe and atpb is reversed with respect to the more typical bacterial organization. the deduced amino acid sequences of the corresponding h(+)-atpase subunits showed significant homology with the subunits from other organisms. results of northern blot analysis showed a transcript at ... | 2000 | 10940012 |
| synthesis and posttranslational regulation of pyruvate formate-lyase in lactococcus lactis. | 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 dependent ... | 2000 | 10940018 |
| structure of dihydroorotate dehydrogenase b: electron transfer between two flavin groups bridged by an iron-sulphur cluster. | the fourth step and only redox reaction in pyrimidine de novo biosynthesis is catalyzed by the flavoprotein dihydroorotate dehydrogenase (dhod). based on their sequences, dhods are grouped into two major families. lactococcus lactis is one of the few organisms with two dhods, a and b, belonging to each of the two subgroups of family 1. the b enzyme (dhodb) is a prototype for dhods in gram-positive bacteria that use nad+ as the second substrate. dhodb is a heterotetramer composed of two different ... | 2000 | 11188687 |
| current strategies for improving food bacteria. | novel concepts and methodologies are emerging that hold great promise for the directed improvement of food-related bacteria, specifically lactic acid bacteria. also, the battle against food spoilage and pathogenic bacteria can now be fought more effectively. here we describe recent advances in microbial physiology and genomic research of these organisms that enable novel strategies for obtaining safe, healthy, and good-tasting fermented food products. | 2000 | 11191806 |
| liver abscess due to lactococcus lactis cremoris. | 2000 | 11192533 | |
| isolation and characterization of carnobacterium, lactococcus, and enterococcus spp. from cooked, modified atmosphere packaged, refrigerated, poultry meat. | the microbiota of commercially produced, cooked and modified atmosphere packaged poultry meat was followed during storage at 3.5 degrees c for up to 7 weeks. the dominant microbiota consisted of lactococcus raffinolactis (117 isolates), carnobacterium divergens (61 isolates), carnobacterium piscicola (11 isolates), lactococcus garvieae (four isolates), lactococcus lactis (one isolate) and enterococcus faecalis (three isolates). all isolates were screened for production of bacteriocins. only c. p ... | 2000 | 11139026 |
| live bacterial delivery systems for development of mucosal vaccines. | by expression of foreign antigens in attenuated strains derived from bacterial pathogens and in non-pathogenic commensal bacteria, recombinant vaccines are being developed that aim to stimulate mucosal immunity. recent advances in the pathogenesis and molecular biology of these bacteria have allowed rational development of new and improved bacterial carriers and more effective gene expression systems. these advances have improved the performance and versatility of these delivery systems to induc ... | 2000 | 11249657 |
| analysis of sugar metabolism in an eps producing lactococcus lactis by 31p nmr. | sugar metabolism and exopolysaccharide (eps) production was analysed in lactococcus lactis by in vivo 31p nmr. transient production of several sugar phosphates, transient depletion of intracellular phosphate, transient production of atp and utp, transient acidification of the medium and alkalinisation of the cytoplasm could be observed in a period of 20 min upon energization by the addition of glucose. eps and non-eps producing variants showed similar nmr spectra, the exception being two ph-depe ... | 2000 | 10674211 |
| expression of green fluorescent protein in lactococcus lactis. | the gfp gene from aequorea victoria, encoding the green fluorescent protein (gfp) has been expressed in lactococcus lactis subsp. lactis biovar cremoris mg1363, upon construction and introduction of plasmid pls1gfp into this host. gfp was monitored in living cells during growth to evaluate its use in molecular and physiological studies. quantification of the levels of gfp expressed by cultures was feasible by fluorescence spectroscopy. phase-contrast and fluorescence microscopy allowed us to dis ... | 2000 | 10675589 |
| coinvasion of dentinal tubules by porphyromonas gingivalis and streptococcus gordonii depends upon binding specificity of streptococcal antigen i/ii adhesin. | cell wall-anchored polypeptides of the antigen i/ii family are produced by many species of oral streptococci. these proteins mediate adhesion of streptococci to salivary glycoproteins and to other oral microorganisms and promote binding of cells to collagen type i and invasion of dentinal tubules. since infections of the root canal system have a mixed anaerobic bacterial etiology, we investigated the hypothesis that coadhesion of anaerobic bacteria with streptococci may facilitate invasive endod ... | 2000 | 10678948 |
| biodegradability of food-associated extracellular polysaccharides. | exopolysaccharides (epss) produced by lactic acid bacteria, which are common in fermented foods, are claimed to have various beneficial physiological effects on humans. although the biodegradability of epss is important in relation to the bioactive properties, knowledge on this topic is limited. therefore, the biodegradability of eight epss, six of which were produced by lactic acid bacteria, was compared with microorganisms from human feces or soil. eps-degradation was determined from the decre ... | 2000 | 10679053 |
| cloning and expression of the genes involved in the production of and immunity against the bacteriocin lacticin rm. | the production of lacticin rm, a novel bacteriocin produced by lactococcus lactis subsp. lactis ez26, is associated with the presence of a 6-kb plasmid, phu1. the information necessary for lacticin rm production and immunity was localized to a 2.5-kb sali-eco47iii fragment. sequencing analysis of this fragment revealed the presence of six open reading frames (orfs). deletion and mutation analyses showed that orfx and orfy are not required for lacticin rm production or immunity, whereas the other ... | 2000 | 10684973 |
| nucleotide sequence analysis of the lactococcal eps plasmid pnz4000. | the complete 42180-bp nucleotide sequence of the mobilization plasmid pnz4000, coding for exopolysaccharide (eps) production in lactococcus lactis, was determined. this plasmid contains a region involved in eps biosynthesis, four functional replicons, a region containing mobilization genes, and three origin of transfer (orit) sequences. sequences identical to these orit sequences were also found on two other lactococcal plasmids and a plasmid from lactobacillus helveticus. several complete and p ... | 2000 | 10686131 |
| expression of clostridium thermocellum endoglucanase gene in lactobacillus gasseri and lactobacillus johnsonii and characterization of the genetically modified probiotic lactobacilli. | endoglucanase a from clostridium thermocellum resistant to pancreatic proteinase was selected out of a range of microbial cellulases expressed in lactobacilli. two lactobacillus-e. coli expression vectors, harboring the endoglucanase gene from c. thermocellum under the control of its own promoter (psd1) and the lactococcus lactis lac a promoter (psd2), were constructed separately. intestinal lactobacillus strains, l. gasseri and l. johnsonii, were electrotransformed with psd1 and psd2, and the s ... | 2000 | 10688695 |
| secretion of biologically active murine interleukin-10 by lactococcus lactis. | we investigated the ability of lactococcus lactis to secrete biologically active, murine interleukin-10 (mil-10). mil-10 was synthesized as a fusion protein, consisting of the mature part of the eukaryotic protein fused to the secretion signal of the lactococcal usp45 protein. the secreted protein was analyzed by page, elisa and bioassay.we show that l. lactis can efficiently secrete biologically active, murine il-10. determination of the n-terminal amino acid sequence confirmed correct processi ... | 2000 | 11118583 |
| isolation of a bacteriocin-producing lactococcus lactis subsp. lactis and application to control listeria monocytogenes in moroccan jben. | use of a bacteriocin-producing lactococcal strain to control listeria monocytogenes in jben. | 2000 | 11123469 |
| metabolism of lactose and citrate by mutants of lactococcus lactis producing excess carbon dioxide. | mutants of lactococcus lactis producing excess carbon dioxide could be isolated on ldha-20 agar (described by el attar et al. journal of dairy research 67 641-646 2000). the use of these mutants in the manufacture of roquefort cheese has the potential to improve the formation of openings in this cheese. the aim of this work was to examine the stability of these mutants, their enzymic activities and their metabolism of lactose and citrate during growth in milk. they produced less l-lactate than t ... | 2000 | 11131070 |
| varying influence of the autolysin, n-acetyl muramidase, and the cell envelope proteinase on the rate of autolysis of six commercial lactococcus lactis cheese starter bacteria grown in milk. | the autolysin, n-acetyl muramidase (acma), of six commercial lactococcus lactis subsp. cremoris starter strains and eight lc. lactis subsp. cremoris derivatives or plasmid-free strains was shown by renaturing sds-page (zymogram analysis) to be degraded by the cell envelope proteinase (lactocepin; ec 3.4.21.96) after growth of strains in milk at 30 degrees c for 72 h. degradation of acma was less in starter strains and derivatives producing lactocepin i/iii (intermediate specificity) than in stra ... | 2000 | 11131071 |
| method for the selection of lactococcus lactis mutants producing excess carbon dioxide. | 2000 | 11131078 | |
| identification and partial characterization of lacticin bh5, a bacteriocin produced by lactococcus lactis bh5 isolated from kimchi. | strain bh5 was isolated from naturally fermented kimchi and identified as a bacteriocin producer that has bactericidal activity against micrococcus flavus atcc 10240. strain bh5 was identified tentatively as lactococcus lactis by api test. lactococcus lactis bh5 showed a broad spectrum of activity against most of the nonpathogenic and pathogenic microorganisms tested by the modified deferred method. the activity of lacticin bh5, named tentatively as the bacteriocin produced by l. lactis bh5, was ... | 2000 | 11131895 |
| specificity mutants of the binding protein of the oligopeptide transport system of lactococcus lactis. | the kinetic properties of wild-type and mutant oligopeptide binding proteins of lactococcus lactis were determined. to observe the properties of the mutant proteins in vivo, the oppa gene was deleted from the chromosome of l. lactis to produce a strain that was totally defective in oligopeptide transport. amplified expression of the oppa gene resulted in an 8- to 12-fold increase in oppa protein relative to the wild-type level. the amplified expression was paralleled by increased bradykinin bind ... | 2000 | 10692365 |
| genetic analysis of chromosomal regions of lactococcus lactis acquired by recombinant lytic phages. | recombinant phages are generated when lactococcus lactis subsp. lactis harboring plasmids encoding the abortive type (abi) of phage resistance mechanisms is infected with small isometric phages belonging to the p335 species. these phage variants are likely to be an important source of virulent new phages that appear in dairy fermentations. they are distinguished from their progenitors by resistance to abi defenses and by altered genome organization, including regions of l. lactis chromosomal dna ... | 2000 | 10698748 |
| multiplex pcr for detection and identification of lactococcal bacteriophages. | three genetically distinct groups of lactococcus lactis phages are encountered in dairy plants worldwide, namely, the 936, c2, and p335 species. the multiplex pcr method was adapted to detect, in a single reaction, the presence of these species in whey samples or in phage lysates. three sets of primers, one for each species, were designed based on conserved regions of their genomes. the c2-specific primers were constructed using the major capsid protein gene (mcp) as the target. the mcp sequence ... | 2000 | 10698762 |
| characterization and determination of origin of lactic acid bacteria from a sorghum-based fermented weaning food by analysis of soluble proteins and amplified fragment length polymorphism fingerprinting. | the group that includes the lactic acid bacteria is one of the most diverse groups of bacteria known, and these organisms have been characterized extensively by using different techniques. in this study, 180 lactic acid bacterial strains isolated from sorghum powder (44 strains) and from corresponding fermented (93 strains) and cooked fermented (43 strains) porridge samples that were prepared in 15 households were characterized by using biochemical and physiological methods, as well as by analyz ... | 2000 | 10698775 |
| cloning, sequencing, and expression of the pyruvate carboxylase gene in lactococcus lactis subsp. lactis c2. | a functional pyc gene was isolated from lactococcus lactis subsp. lactis c2 and was found to complement a pyc defect in l. lactis kb4. the deduced lactococcal pyc protein was highly homologous to pyc sequences of other bacteria. the pyc gene was also detected in lactococcus lactis subsp. cremoris and l. lactis subsp. lactis bv. diacetylactis strains. | 2000 | 10698798 |
| molecular characterization of the lactococcal plasmid pcis3: natural stacking of specificity subunits of a type i restriction/modification system in a single lactococcal strain. | a 6.1 kb plasmid from the lactococcus lactis subsp. cremoris strain uc509.9, named pcis3, was found to mediate a restriction/modification (r/m) phenotype. nucleotide sequence analysis of pcis3 revealed the presence of an hsds gene, typical of type i r/m systems. the presence of this plasmid resulted in a 10(4)-fold reduction in the efficiency of plating (e.o.p.) of unmodified phage. in addition to the hsds gene of pcis3, two more hsds genes were identified in strain uc509.9, one located on the c ... | 2000 | 10708382 |
| microbiological and molecular impacts of abik on the lytic cycle of lactococcus lactis phages of the 936 and p335 species. | the lactococcal abortive infection mechanism abik was previously shown to be highly effective against the small isometric-headed bacteriophage ul36 of the p335 species, as evidenced by an efficiency of plaquing (e.o.p.) of 10(-6), a 14-fold reduction in the burst size and an efficiency at which centres of infection form (e.c.o.i.) of 0.5%. no phage dna was detected in the infected abik+ cells [emond, e., holler, b. j., boucher, i., vandenbergh, p. a., vedamuthu, e. r., kondo, j. k. & moineau, s. ... | 2000 | 10708383 |
| htra is the unique surface housekeeping protease in lactococcus lactis and is required for natural protein processing. | we identified an exported protease in lactococcus lactis ssp. lactis strain il1403 belonging to the htra/degp family. inactivation of the chromosomal gene (htrall) encoding this protease (htrall) results in growth thermo-sensitivity at very high temperatures (above 37 degrees c for l. lactis). the role of htrall in extracellular proteolysis under normal growth conditions was examined by testing the stability of different exported proteins (i.e. fusions, a heterologous pre-pro-protein or a native ... | 2000 | 10712686 |
| [attempts to prepare aseptic and non-salt miso by the use of bacteriocins produced by lactic acid bacteria]. | 2000 | 10714180 | |
| an effective lacticin biopreservative in fresh pork sausage. | lacticin 3147 is a novel heat-stable bacteriocin, produced by lactococcus lactis dpc 3147, that exhibits a broad-range inhibition spectrum similar to nisin. in this study, the effect of lacticin 3147 and nisin on the shelf life of fresh pork sausage and their ability to control pathogens (clostridium perfringens dsm 756, salmonella kentucky at1) and nonpathogenic listeria innocua dpc 1770 was investigated. the following preservative regimens were evaluated, both in broth and sausage systems: (i) ... | 2000 | 10716567 |
| rules for dna target-site recognition by a lactococcal group ii intron enable retargeting of the intron to specific dna sequences. | group ii intron homing occurs primarily by a mechanism in which the intron rna reverse splices into a dna target site and is then reverse transcribed by the intron-encoded protein. the dna target site is recognized by an rnp complex containing the intron-encoded protein and the excised intron rna. here, we analyzed dna target-site requirements for the lactococcus lactis ll.ltrb group ii intron in vitro and in vivo. our results suggest a model similar to yeast mtdna introns, in which the intron-e ... | 2000 | 10716944 |
| the development of tnnuc and its use for the isolation of novel secretion signals in lactococcus lactis. | we have previously used tn917 for the identification and characterization of regulated promoters from lactococcus lactis [israelsen et al., appl. environ. microbiol. 61 (1995) 2540-2547]. we describe here the construction of a new tn917-transposon derivative, termed tnnuc, which includes the staphylococcus aureus nuclease gene (nuc) as a reporter for secretion. transposition of tnnuc into the l. lactis chromosome allows the generation of fusions in-frame with the nuc gene. tnnuc includes also la ... | 2000 | 10721729 |
| group b streptococci and other gram-positive cocci bind to cytokeratin 8. | group b streptococci (gbs) adhere to surface receptors present on epithelial cells; these receptors include fibronectin and laminin. to identify other possible receptors, plasma membranes from a549 cells, a respiratory tract epithelial cell line, were prepared. these plasma membranes were tested in a protein blot analysis using radiolabeled gbs as a probe. gbs adhered to two species, with molecular masses of 50 kda (p50) and 57 kda (p57). we concluded that p50 and p57 correspond to two forms of ... | 2000 | 10722610 |
| structural characterisation and enzymic modification of the exopolysaccharide produced by lactococcus lactis subsp. cremoris b39. | lactococcus lactis subsp. cremoris b39 grown on whey permeate produced an exopolysaccharide containing l-rha, d-gal and d-glc in a molar ratio of 2:3:2. the polysaccharide was modified using an enzyme preparation from aspergillus aculeatus, resulting in the release of gal and a polymer with approximately the same hydrodynamic volume as the native polysaccharide. linkage analysis and 1h nmr studies of both the native and modified exopolysaccharides elucidated that terminally linked gal was releas ... | 2000 | 10724531 |
| heterologous inducible expression of enterococcus faecalis pcf10 aggregation substance asc10 in lactococcus lactis and streptococcus gordonii contributes to cell hydrophobicity and adhesion to fibrin. | aggregation substance proteins encoded by the sex pheromone plasmid family of enterococcus faecalis have been shown previously to contribute to the formation of a stable mating complex between donor and recipient cells and have been implicated in the virulence of this increasingly important nosocomial pathogen. in an effort to characterize the protein further, prgb, the gene encoding the aggregation substance asc10 on pcf10, was cloned in a vector containing the nisin-inducible nisa promoter and ... | 2000 | 10735875 |