Publications

cloning and sequencing of the pz-peptidase gene from bacillus licheniformis n22.	pz-peptidase is an endopeptidase that cleaves the synthetic substrate pz-peptide (4-phenylazobenzyloxycarbonyl-pro-leu-gly-pro-arg), which was originally developed for the assay of collagenase. the pz-peptidase gene of bacillus licheniformis n22 was cloned and sequenced. the gene consists of 628 amino acids with a motif for zinc-dependent metalloprotease, and shares 42% amino acid identity with the oligoendopeptidase of lactococcus lactis. this is the first report on the gene structure of a pz-p ...	1999	16232456
continuous production of lactic acid from molasses by perfusion culture of lactococcus lactis using a stirred ceramic membrane reactor.	a perfusion culture system was used for continuous production of lactic acid by retaining cells at a high density of lactococcus lactis in a stirred ceramic membrane reactor (scmr). after the cell concentration increased to 248 g/l, half of the culture broth volume was replaced with the fermentation medium. subsequently, a substrate solution containing glucose (run 1) or molasses (run 2) was continuously supplied to the cells retained in the scmr. simultaneously, the culture supernatant was extr ...	1999	16232533
purification and characterization of a bacteriocin produced by lactococcus lactis subsp. lactis h-559 isolated from kimchi.	lactic acid bacteria were isolated from kimchi and screened for bacteriocin production. strain h-559, identified as lactococcus lactis subsp. lactis, exhibited the strongest antibacterial activity among them and was active against pathogenic bacteria such as listeria monocytogenes and staphylococcus aureus as well as many lactic acid bacteria. the antimicrobial substance produced by l. lactis subsp. lactis h-559 was inactivated by alpha-chymotrypsin, and protease type ix and xiv and was confirme ...	1999	16232590
uncoupling of growth and exopolysaccharide production by lactococcus lactis subsp. cremoris nizo b40 and optimization of its synthesis.	exopolysaccharide (eps) production by lactococcus lactis subsp. cremoris nizo b40 was found to be most efficient with glucose as a substrate. the optimal temperature and ph for eps synthesis were 25 degrees c and ph 5.8, respectively. eps production could not be identified as a stress response: increased oxygen tension and reduced water activity negatively affected both growth and eps synthesis. it is often assumed that there is a competition between growth and eps formation. within the range of ...	1999	16232594
complete growth inhibition of bacillus subtilis by nisin-producing lactococci in fermented soybeans.	the growth inhibition by nisin-producing lactococci against bacillus subtilis and its application to soybean miso fermentation were investigated. lactococcus lactis subsp. lactis ifo12007 (nisin-producing, salt-intolerant) rapidly proliferated to more than 10(9) cells/g in cooked soybeans without any excessive ph decrease. in spite of the mild decrease in ph, the growth of b. subtilis was completely inhibited; no living cells were detected in a soybean sample inoculated with 10(6) cells/g and in ...	1999	27389100
determination of the phosphorylated sugars of the embden-meyerhoff-parnas pathway in lactococcus lactis using a fast sampling technique and solid phase extraction.	an experimental procedure for the determination of intracellular concentrations of the phosphorylated sugars in the lactic acid bacterium lactococcus lactis is presented. the first step of the procedure is a rapid sampling of a small volume of the growth medium into 60% (v/v) methanol precooled to -35 degrees c, bringing about a fast and complete stop of all metabolic activity. in contrast to yeast the metabolites leak out of the cells when these are brought into contact with methanol and are pr ...	1999	10099615
characterization of lactic acid bacteria isolated from a thai low-salt fermented fish product and the role of garlic as substrate for fermentation.	lactic acid bacteria (lab) isolated from raw materials (fish, rice, garlic and banana leaves) and processed som-fak (a thai low-salt fermented fish product) were characterized by api 50-ch and other phenotypic criteria. lactococcus lactis subsp. lactis and leuconostoc citreum were specifically associated with fish fillet and minced fish, lactobacillus paracasei subsp. paracasei with boiled rice and weisella confusa with garlic mix and banana leaves. in addition, lactobacillus plantarum, lactobac ...	1999	10100902
role of calcium in activity and stability of the lactococcus lactis cell envelope proteinase.	the mature lactococcal cell envelope proteinase (cep) consists of an n-terminal subtilisin-like proteinase domain and a large c-terminal extension of unknown function whose far end anchors the molecule in the cell envelope. different types of cep can be distinguished on the basis of specificity and amino acid sequence. removal of weakly bound ca2+ from the native cell-bound cep of lactococcus lactis sk11 (type iii specificity) is coupled with a significant reversible decrease in specific activit ...	1999	10103227
characterization and heterologous expression of the genes encoding enterocin a production, immunity, and regulation in enterococcus faecium dpc1146.	enterocin a is a small, heat-stable, antilisterial bacteriocin produced by enterococcus faecium dpc1146. the sequence of a 10, 879-bp chromosomal region containing at least 12 open reading frames (orfs), 7 of which are predicted to play a role in enterocin biosynthesis, is presented. the genes enta, enti, and entf encode the enterocin a prepeptide, the putative immunity protein, and the induction factor prepeptide, respectively. the deduced proteins entk and entr resemble the histidine kinase an ...	1999	10103244
identification of four phage resistance plasmids from lactococcus lactis subsp. cremoris ho2.	the bacteriophage-host sensitivity patterns of 16 strains of lactococcus lactis originally isolated from a mixed strain cheddar cheese starter culture were determined. using phages obtained from cheese factory whey, four of the strains were found to be highly phage resistant. one of these isolates, lactococcus lactis subsp. cremoris ho2, was studied in detail to determine the mechanisms responsible for the phage insensitivity phenotypes. conjugal transfer of plasmid dna from strain ho2 allowed a ...	1999	10103248
a comparative analysis of the citrate permease p mrna stability in lactococcus lactis biovar diacetylactis and escherichia coli.	the role of ribonucleases in the control of gene expression remains unknown in lactic acid bacteria. in the present work, we analysed the expression of the citp gene, which encodes the lactococcal citrate permease p, through the stability of the citqrp messenger in both lactococcus lactis biovar diacetylactis (l. diacetylactis) and escherichia coli. the chemical half-life for citqrp mrna observed in l. diacetylactis wild-type strain was abnormally long for bacteria. it was even longer than that ...	1999	10188238
screening of lactic acid bacteria for bile salt hydrolase activity.	bile salt hydrolysis is an important metabolic reaction in the bile salt metabolism of mammals. this reaction has a facilitating effect for bile salt excretion but can also be involved in various illnesses. in recent years interest has increased to use bile salt hydrolysis to influence the cholesterol metabolism of humans and farm animals. to understand the distribution and range of bile salt hydrolase activity in lactic acid bacteria, we screened more than 300 strains of the genera bifidobacter ...	1999	10629797
the natural food grade inhibitor, lacticin 3147, reduced the incidence of mastitis after experimental challenge with streptococcus dysgalactiae in nonlactating dairy cows.	lacticin 3147 is a broad-spectrum bacteriocin produced by the food-grade organism lactococcus lactis. lacticin 3147 is active at a neutral ph and has been shown to be bactericidal to streptococci and staphylococci in vitro. the effectiveness of an intramammary teat seal formulation, and a teat seal containing lacticin 3147 was evaluated at drying off in 68 uninfected quarters of 18 cows. following infusion of either teat seal or lacticin 3147 combined with teat seal, a deliberate infection chall ...	1999	10629810
occurrence of nisin z production in lactococcus lactis bfe 1500 isolated from wara, a traditional nigerian cheese product.	screening for bacteriocin production of 500 strains of lactic acid bacteria (lab) from various african fermented foods resulted in the detection of a bacteriocin producing lactococcus lactis (bfe 1500) isolated from a dairy product called wara. the bacteriocin inhibited not only the closely related lab, but also strains of listeria monocytogenes, listeria innocua, clostridium butyricum, clostridium perfringens, bacillis cereus and staphylococcus aureus. it was heat stable even at autoclaving tem ...	1999	10634705
nucleotide sequence and thermostability of pnd324, a 3.6-kb plasmid from lactococcus lactis.	a 3.6-kb plasmid, designated pnd324, was isolated from lactococcus lactis subsp. lactis ll57-1. sequence analysis revealed the presence of three open reading frames, rep324, orfx1 and orfx2, which are flanked by two non-coding regions, ori324 and cise. the minimal replication region of pnd324 consists of ori324 and rep324, which is closely related to the lactococcal theta-type replicons of the pwv02/pci305 family. pnd324 was stable at both 30 degrees c and 37 degrees c, whereas derivatives that ...	1999	10645623
cloning, dna sequence analysis, and deletion of a gene encoding diacetyl-acetoin reductase from lactococcus lactis.	diacetyl is produced by strains of lactic acid bacteria used in the dairy industry. production of this important flavour compound could be increased by genetic manipulation of genes encoding enzymes involved in diacetyl metabolism. this paper reports the cloning and sequencing of the gene (dar) encoding diacetyl-acetoin reductase from lactococcus lactis. analysis of the dna sequence of the dar gene and surrounding area revealed the presence of a putative operon with similarity to the family of a ...	1999	10647818
effect of elevated oxygen and carbon dioxide on the surface growth of vegetable-associated micro-organisms.	the impact of a novel type of modified atmosphere (ma), referred to as high o2-ma, on micro-organisms associated with the spoilage of minimally-processed vegetables was studied. pure cultures of pseudomonas fluorescens, enterobacter agglomerans, aureobacterium strain 27, candida guilliermondii, c. sake, salmonella typhimurium, salm. enteritidis, escherichia coli, listeria monocytogenes, leuconostoc mesenteroides var. mesenteroides, lactobacillus plantarum and lactococcus lactis were cultured on ...	1999	10196748
genetic diversity among dairy lactococcal strains investigated by polymerase chain reaction with three arbitrary primers.	randomly amplified polymorphic dna (rapd) has been used for the rapid typing of lactococcus lactis strains isolated from raw milk from the camembert region of normandy. it is thought that the diversity and perhaps the area strain specificity due to climatic and geographical factors of such wild-type lactococcal strains could contribute to the flavour differences and specific features detected for the same product in different areas. the patterns from 58 isolates were analysed by upgma dendrogram ...	1999	10196756
nisin a depletes intracellular atp and acts in bactericidal manner against mycobacterium smegmatis.	nisin is a bacteriocin produced by many strains of lactococcus lactis. this study examined the effect of nisin on mycobacterium smegmatis, a non-pathogenic species of mycobacterium. nisin had a minimum inhibitory concentration of 8.0 micrograms ml-1 and a minimum inhibitory dose of 7.5 micrograms ml-1 against myco. smegmatis. treatment with 25.0 micrograms ml-1 nisin caused partial inhibition of myco smegmatis; the survivors were nisin-sensitive when tested in a separate experiment. mycobacteriu ...	1999	10196766
two operons that encode fnr-like proteins in lactococcus lactis.	global regulatory circuits of the type mediated by crp and fnr in escherichia coli were sought in lactococcus lactis to provide a basis for redirecting carbon metabolism to specific fermentation products. using a polymerase chain reaction (pcr) approach, two genes (flpa and flpb) encoding fnr-like proteins (flpa and flpb) with the potential for mediating a dithiol-disulphide-dependent regulatory switch, were identified. transcript analysis indicated that they are distal genes of two paralogous o ...	1999	10200970
detection and characterization of a bacteriocin produced by lactococcus lactis subsp. cremoris r isolated from radish.		1999	10206654
post-translational modification of nisin. the involvement of nisb in the dehydration process.	the lantibiotic nisin is an antimicrobial peptide produced by lactococcus lactis. as with all lantibiotics, nisin contains a number of dehydro-residues and thioether amino acids that introduce five lanthionine rings into the target peptide. these atypical amino acids are introduced by post-translational modification of a ribosomally synthesized precursor peptide. in certain cases, the serine residue, at position 33 of nisin, does not undergo dehydration to dha33. with native nisin this partially ...	1999	10215865
molecular characterization of the ph-inducible and growth phase-dependent promoter p170 of lactococcus lactis.	in a previous study, we described the use of transposon tn917-ltv1 for identification of environmentally regulated promoters in lactococcus lactis. here, we report the molecular analysis of one of these promoters, p170, that is upregulated at low ph during the transition to stationary phase. the minimal dna region required for both promoter activity and ph regulation was mapped to a 51 bp fragment located 7 bp upstream of the transcriptional start site. this fragment lacked the consensus -35 pro ...	1999	10216861
molecular characterization of a phage-encoded resistance system in lactococcus lactis.	a specific fragment of the genome of tuc2009, a temperate lactococcal bacteriophage, was shown to contain several open reading frames, whose deduced protein products exhibited similarities to proteins known to be involved in dna replication and modification. in this way, a putative single-stranded binding protein, replisome organizer protein, topoisomerase i, and a methylase were identified. when the genetic information coding for the putative replisome organizer protein of tuc2009, rep2009, was ...	1999	10223975
excision of the conjugative transposon tn916 in lactococcus lactis.	in lactococcus lactis excision of tn916 is limited by the concentration of integrase and is increased by providing more excisionase. however, even with increased excision of tn916 in l. lactis, no conjugative transfer is detectable. this suggests that l. lactis is deficient in a host factor(s) required for conjugative transposition.	1999	10224024
survival of enterococcus faecalis in mouse peritoneal macrophages.	enterococcus faecalis was tested for the ability to persist in mouse peritoneal macrophages in two separate studies. in the first study, the intracellular survival of serum-passaged e. faecalis 418 and two isogenic mutants [cytolytic strain fa2-2(pam714) and non-cytolytic strain fa2-2(pam771)] was compared with that of escherichia coli dh5alpha by infecting balb/c mice intraperitoneally and then monitoring the survival of the bacteria within lavaged peritoneal macrophages over a 72-h period. all ...	1999	10225869
cloning of branched chain amino acid biosynthesis genes and assays of alpha-acetolactate synthase activities in leuconostoc mesenteroides subsp. cremoris.	a genomic library from leuconostoc mesenteroides subsp. cremoris (lmc) in escherichia coli was screened for alpha-acetolactate synthase (als) activity using a phenotypic test detecting the production of acetolactate or related c4 derivatives (diacetyl, acetoin or 2,3-butanediol) in the culture. four recombinant e. coli clones, with plasmids containing overlapping dna fragments and displaying anabolic als activity, were selected. this activity is encoded by an ilvb gene belonging to a putative op ...	1999	10229948
extensive post-translational modification, including serine to d-alanine conversion, in the two-component lantibiotic, lacticin 3147.	lacticin 3147 is a two-component bacteriocin produced by lactococcus lactis subspecies lactis dpc3147. in order to further characterize the biochemical nature of the bacteriocin, both peptides were isolated which together are responsible for the antimicrobial activity. the first, ltna1, is a 3,322 da 30-amino acid peptide and the second component, ltna2, is a 29-amino acid peptide with a mass of 2,847 da. conventional amino acid analysis revealed that both peptides contain the thioether amino ac ...	1999	10608807
tetrameric n(5)-(l-1-carboxyethyl)-l-ornithine synthase: guanidine. hcl-induced unfolding and a low temperature requirement for refolding.	guanidine x hcl (gdnhcl)-induced unfolding of tetrameric n(5)-(l-1-carboxyethyl)-l-ornithine synthase (ceos; 141,300 m(r)) from lactococcus lactis at ph 7.2 and 25 degrees c occurred in several phases. the enzyme was inactivated at approximately 1 m gdnhcl. a time-, temperature-, and concentration-dependent formation of soluble protein aggregates occurred at 0.5-1.5 m gdnhcl due to an increased exposure of apolar surfaces. a transition from tetramer to unfolded monomer was observed between 2 and ...	1999	10525296
dihydroorotate dehydrogenase b of enterococcus faecalis. characterization and insights into chemical mechanism.	enterococcus faecalis dihydroorotate dehydrogenase b is a heterodimer of 28 and 33 kda encoded by the pyrk and pyrdb genes. both subunits copurify during all chromatographic steps, and, as determined by hplc, one fmn and one fad are bound per heterodimer. the enzyme catalyzes efficient oxidation of 4-s-nadh by orotate. isotope effect and ph data suggest that reduction of flavin by nadh at the pyrk site is only partially rate limiting with no kinetically significant proton transfer occurring in t ...	1999	10529184
the secondary multidrug transporter lmrp contains multiple drug interaction sites.	the secondary multidrug transporter lmrp of lactococcus lactis mediates the efflux of hoechst 33342 from the cytoplasmic leaflet of the membrane. kinetic analysis of hoechst 33342 transport in inside-out membrane vesicles of l. lactis showed that the lmrp-mediated h(+)/hoechst 33342 antiport reaction obeyed michaelis-menten kinetics, with a low apparent affinity constant of 0.63 microm hoechst 33342 (= 0.5 mmol hoechst 33342/mol phospholipid). several drugs significantly inhibited lmrp-mediated ...	1999	10529235
the natural food grade inhibitor, lacticin 3147, reduced the incidence of mastitis after experimental challenge with streptococcus dysgalactiae in nonlactating dairy cows.	lacticin 3147 is a broad-spectrum bacteriocin produced by the food-grade organism lactococcus lactis. lacticin 3147 is active at a neutral ph and has been shown to be bactericidal to streptococci and staphylococci in vitro. the effectiveness of an intramammary teat seal formulation, and a teat seal containing lacticin 3147 was evaluated at drying off in 68 uninfected quarters of 18 cows. following infusion of either teat seal or lacticin 3147 combined with teat seal, a deliberate infection chall ...	1999	10531595
low-redundancy sequencing of the entire lactococcus lactis il1403 genome.	lactococcus lactis is an at-rich gram positive bacterium phylogenetically close to the genus streptococcus. various strains of l. lactis are used in dairy industry as starters for cheese making. l. lactis is also one of the well characterized laboratory microorganisms, widely used for studies on physiology of lactic acid bacteria. we describe here a low redundancy sequence of the genome of the strain l. lactis il1403. the strategy which we followed to determine the sequence consists of two main ...	1999	10532372
group ii introns and expression of conjugative transfer functions in lactic acid bacteria.	the homologous lactococcal conjugative elements prs01 and the sex factor of lactococcus lactis strain 712 both contain a group ii intron within a gene believed to encode a conjugative relaxase enzyme. this enzyme is responsible for nicking of dna at the origin of transfer (orit) sequence of the sex factor dna to initiate the strand transfer process. group ii introns have been studied in eukaryotes, and several of these elements in yeast mitochondrial genes have received considerable attention. t ...	1999	10532373
acquired antibiotic resistance in lactic acid bacteria from food.	acquired antibiotic resistance, i.e. resistance genes located on conjugative or mobilizable plasmids and transposons can be found in species living in habitats (e.g. human and animal intestines) which are regularly challenged with antibiotics. most data are available for enterococci and enteric lactobacilli. raw material from animals (milk and meat) which are inadvertantly contaminated with fecal matters during production will carry antibiotic resistant lactic acid bacteria into the final fermen ...	1999	10532375
multi-domain, cell-envelope proteinases of lactic acid bacteria.	the multi-domain, cell-envelope proteinases encoded by the genes prtb of lactobacillus delbrueckii subsp. bulgaricus, prth of lactobacillus helveticus, prtp of lactococcus lactis, scpa of streptococcus pyogenes and csp of streptococcus agalactiae have been compared using multiple sequence alignment, secondary structure prediction and database homology searching methods. this comparative analysis has led to the prediction of a number of different domains in these cell-envelope proteinases, and th ...	1999	10532376
bioactive peptides encrypted in milk proteins: proteolytic activation and thropho-functional properties.	the bioactivities of peptides encrypted in major milk proteins are latent until released and activated by enzymatic proteolysis, e.g. during gastrointestinal digestion or food processing. the proteolytic system of lactic acid bacteria can contribute to the liberation of bioactive peptides. in vitro, the purified cell wall proteinase of lactococcus lactis was shown to liberate oligopeptides from beta- and alpha-caseins which contain amino acid sequences present in casomorphins, casokinines, and i ...	1999	10532380
peptidases and amino acid catabolism in lactic acid bacteria.	the conversion of peptides to free amino acids and their subsequent utilization is a central metabolic activity in prokaryotes. at least 16 peptidases from lactic acid bacteria (lab) have been characterized biochemically and/or genetically. among lab, the peptidase systems of lactobacillus helveticus and lactococcus lactis have been examined in greatest detail. while there are homologous enzymes common to both systems, significant differences exist in the peptidase complement of these organisms. ...	1999	10532381
multidrug resistance in lactic acid bacteria: molecular mechanisms and clinical relevance.	the active extrusion of cytotoxic compounds from the cell by multidrug transporters is one of the major causes of failure of chemotherapeutic treatment of tumor cells and of infections by pathogenic microorganisms. the secondary multidrug transporter lmrp and the atp-binding cassette (abc) type multidrug transporter lmra in lactococcus lactis are representatives of the two major classes of multidrug transporters found in pro- and eukaryotic organisms. therefore, knowledge of the molecular proper ...	1999	10532389
exopolysaccharides produced by lactococcus lactis: from genetic engineering to improved rheological properties?	over the last years, important advances have been made in the study of the production of exopolysaccharides (eps) by several lactic acid bacteria, including lactococcus lactis. from different eps-producing lactococcal strains the specific eps gene clusters have been characterised. they contain eps genes, which are involved in eps repeating unit synthesis, export, polymerisation, and chain length determination. the function of the glycosyltransferase genes has been established and the availabilit ...	1999	10532391
introduction of peptidase genes from lactobacillus delbrueckii subsp. lactis into lactococcus lactis and controlled expression.	peptidases pepi, pepl, pepw, and pepg from lactobacillus delbrueckii subsp. lactis, which have no counterparts in lactococcus lactis, and peptidase pepq were examined to determine their potential to confer new peptidolytic properties to lactococci. controllable expression of the corresponding genes (pep genes) was achieved by constructing translational fusions with the promoter of the nisa gene (p(nisa)). a suitable host strain, uklc10, was constructed by chromosomal integration of the genes enc ...	1999	10543778
in vitro utilization of amylopectin and high-amylose maize (amylomaize) starch granules by human colonic bacteria.	it has been well established that a certain amount of ingested starch can escape digestion in the human small intestine and consequently enters the large intestine, where it may serve as a carbon source for bacterial fermentation. thirty-eight types of human colonic bacteria were screened for their capacity to utilize soluble starch, gelatinized amylopectin maize starch, and high-amylose maize starch granules by measuring the clear zones on starch agar plates. the six cultures which produced cle ...	1999	10543795
genetic characterization of the major lactococcal aromatic aminotransferase and its involvement in conversion of amino acids to aroma compounds.	in lactococci, transamination is the first step of the enzymatic conversion of aromatic and branched-chain amino acids to aroma compounds. in previous work we purified and biochemically characterized the major aromatic aminotransferase (arat) of a lactococcus lactis subsp. cremoris strain. here we characterized the corresponding gene and evaluated the role of arat in the biosynthesis of amino acids and in the conversion of amino acids to aroma compounds. amino acid sequence homologies with other ...	1999	10543798
survival, physiology, and lysis of lactococcus lactis in the digestive tract.	the survival and the physiology of lactococcal cells in the different compartments of the digestive tracts of rats were studied in order to know better the fate of ingested lactic acid bacteria after oral administration. for this purpose, we used strains marked with reporter genes, the luxa-luxb gene of vibrio harveyi and the gfp gene of aequora victoria, that allowed us to differentiate the inoculated bacteria from food and the other intestinal bacteria. luciferase was chosen to measure the met ...	1999	10543799
the ald gene, encoding a coenzyme a-acylating aldehyde dehydrogenase, distinguishes clostridium beijerinckii and two other solvent-producing clostridia from clostridium acetobutylicum.	the coenzyme a (coa)-acylating aldehyde dehydrogenase (aldh) catalyzes a key reaction in the acetone- and butanol (solvent)-producing clostridia. it reduces acetyl-coa and butyryl-coa to the corresponding aldehydes, which are then reduced by alcohol dehydrogenase (adh) to form ethanol and 1-butanol. the aldh of clostridium beijerinckii nrrl b593 was purified. it had no adh activity, was nad(h) specific, and was more active with butyraldehyde than with acetaldehyde. the n-terminal amino acid sequ ...	1999	10543811
regulation of exopolysaccharide production by lactococcus lactis subsp. cremoris by the sugar source.	lactococcus lactis produced more exopolysaccharide (eps) on glucose than on fructose as the sugar substrate, although the transcription level of the eps gene cluster was independent of the sugar source. a major difference between cells grown on the two substrates was the capacity to produce sugar nucleotides, the eps precursors. however, the activities of the enzymes required for the synthesis of nucleotide sugars were not changed upon growth on different sugars. the activity of fructosebisphosp ...	1999	10543815
pcr amplification of the gene acma differentiates lactococcus lactis subsp. lactis and l. lactis subsp. cremoris.	the occurrence of the acma gene, encoding the lactococcal n-acetylmuramidase in new lactococcal isolates from raw milk cheeses, has been determined. isolates were genotypically identified to the subspecies level with a pcr technique. on the basis of pcr amplification of the acma gene, the presence or absence of an additional amplicon of approximately 700 bp correlated with lactococcus lactis subspecies. l. lactis subsp. lactis exhibits both the expected 1,131-bp product and the additional amplic ...	1999	10543836
kinetics and consequences of binding of nona- and dodecapeptides to the oligopeptide binding protein (oppa) of lactococcus lactis.	the oligopeptide transport system (opp) of lactococcus lactis belongs to the class of binding protein-dependent abc-transporters. this system has the unique capacity to mediate the uptake of peptides from 4 up to at least 18 residues. kinetic analysis of peptide binding to the binding protein, oppa, revealed a relationship between the peptide dissociation constants and the length of the ligand. the dissociation constants varied from submicromolar for dodecapeptides to millimolar for pentapeptide ...	1999	10545166
characterization in vitro and in vivo of a new hu family protein from streptococcus thermophilus st11.	streptococcus thermophilus is a thermophilic gram-positive bacterium belonging to the lactic acid group. we report the isolation and characterization of a new 9.6-kda dna-binding protein, hsth, belonging to the hu family of nucleoid-associated proteins. the hsth gene was isolated in a 2.5-kb genomic region, upstream of a gene with strong homology to lactococcus lactis pyrd. it is transcribed from a single e. coli sigma(70)-like promoter. based on its high level of sequence similarity to b. subti ...	1999	10545259
n5-(l-1-carboxyethyl)-l-ornithine synthase: physical and spectral characterization of the enzyme and its unusual low pka fluorescent tyrosine residues.	n5-(l-1-carboxyethyl)-l-ornithine synthase [e.c. 1.5.1.24] (ceos) from lactococcus lactis has been cloned, expressed, and purified from escherichia coli in quantities sufficient for characterization by biophysical methods. the nadph-dependent enzyme is a homotetramer (mr approximately equal to 140,000) and in the native state is stabilized by noncovalent interactions between the monomers. the far-ultraviolet circular dichroism spectrum shows that the folding pattern of the enzyme is typical of t ...	1999	10548058
a protein-based phylogenetic tree for gram-positive bacteria derived from hrca, a unique heat-shock regulatory gene.	the dnak operon from bacillus subtilis and other gram-positive bacteria with low g + c dna content contains additional heat-shock genes, including hrca. the hrca gene encodes a transcription factor that negatively regulates heat-shock genes and is uniformly present in all gram-positive bacteria studied to date. an hrca homologue is also present in synechocystis species, leptospira interrogans, chlamydia trachomatis, caulobacter crescentus and methanococcus jannaschii, organisms that diverged ear ...	1999	10555317
comparison of partial malolactic enzyme gene sequences for phylogenetic analysis of some lactic acid bacteria species and relationships with the malic enzyme.	dna sequences covering 36% of the mle gene that encodes the malolactic enzyme were determined for 13 strains of lactic acid bacteria, representing pediococcus, leuconostoc, lactobacillus and oenococcus genera. the sequences were aligned with the corresponding region of mles in lactococcus lactis. the phylogenetic distance matrix tree of all mle sequences was compared with the 16s rrna phylogenetic tree. the analysis showed that the mle fragment evolved more rapidly than the 16s gene and differen ...	1999	10555321
tpw22, a lactococcal temperate phage with a site-specific integrase closely related to streptococcus thermophilus phage integrases.	the temperate phage tpw22, induced from lactococcus lactis subsp. cremoris w22, and the evolutionarily interesting integrase of this phage were characterized. phage tpw22 was propagated lytically on l. lactis subsp. cremoris 3107, which could also be lysogenized by site-specific integration. the attachment site (attp), 5'-taaggcgacggtcg-3', of phage tpw22 was present on a 7.5-kb ecori fragment, a 3.4-kb ecori-hindiii fragment of which was sequenced. sequence information revealed the presence of ...	1999	10559170
novel organization of genes involved in prophage excision identified in the temperate lactococcal bacteriophage tp901-1.	in this work, the phage-encoded proteins involved in site-specific excision of the prophage genome of the temperate lactococcal bacteriophage tp901-1 were identified. the phage integrase is required for the process, and a low but significant frequency of excision is observed when the integrase is the only phage protein present. however, 100% excision is observed when the phage protein orf7 is provided as well as the integrase. thus, orf7 is the tp901-1 excisionase, and it is the first excisionas ...	1999	10572133
behaviour of l. monocytogenes in an artificially made biofilm of a nisin-producing strain of lactococcus lactis.	the survival of listeria monocytogenes in a binary biofilm with a bacteriocin producer (lactococcus lactis cnrz 150) was investigated. two situations were simulated: in the first, l. monocytogenes was deposited on a 1-day biofilm of lactococcus lactis (deferred adhesion); in the second, l. monocytogenes was simultaneously mixed with lact. lactis (simultaneous adhesion). biofilms were cultivated in tryptic soy broth supplemented with 6 g l(-1) of yeast extract (tsb-ye) and l. monocytogenes counts ...	1999	10574092
novel polymer-polymer conjugates for recovery of lactic acid by aqueous two-phase extraction.	a new family of polymer conjugates is proposed to overcome constraints in the applicability of aqueous two-phase systems for the recovery of lactic acid. polyethylene glycol-polyethylenimine (pei) conjugates and ethylene oxide propylene oxide-pei (eopo-pei) conjugates were synthesized. aqueous two-phase systems were generated when the conjugates were mixed with fractionated dextran or crude hydrolyzed starch. with 2% phosphate buffer in the systems, phase diagrams with critical points of 3.9% eo ...	1999	10578091
structure-function analysis of multidrug transporters in lactococcus lactis.	the active extrusion of cytotoxic compounds from the cell by multidrug transporters is one of the major causes of failure of chemotherapeutic treatment of tumor cells and of infections by pathogenic microorganisms. a multidrug transporter in lactococcus lactis, lmra, is a member of the atp-binding cassette (abc) superfamily and a bacterial homolog of the human multidrug resistance p-glycoprotein. another multidrug transporter in l. lactis, lmrp, belongs to the major facilitator superfamily, and ...	1999	10581356
production and utilization of polyclonal antibodies against nisin in an elisa and for immuno-location of nisin in producing and sensitive bacterial strains.	specific nisin polyclonal antibodies (pab) were produced in rabbits using nisin z produced by lactococcus lactis subsp. lactis biovar diacetylactis ul 719. antisera were obtained from white female new zealand rabbits that were first immunized with a nisin z-keyhole limpet haemocyanin conjugate and boosted with free nisin z. nisin-specific pab were purified by affinity chromatography with a yield of 15 mg specific antinisin 100 ml-1 serum. the detection limit of the elisa test for nisin z was 0.7 ...	1999	10583677
molecular and physiological characterization of dominant bacterial populations in traditional mozzarella cheese processing	the development of the dominant bacterial populations during traditional mozzarella cheese production was investigated using physiological analyses and molecular techniques for strain typing and taxonomic identification. analysis of rapd fingerprints revealed that the dominant bacterial community was composed of 25 different biotypes, and the sequence analysis of 16s rdna demonstrated that the isolated strains belonged to leuconostoc mesenteroides subsp. mesenteroides, leuc. lactis, streptococcu ...	1999	10583686
microbiological characteristics of anevato: a traditional greek cheese	nine batches of anevato, raw goat milk cheese, were examined throughout a 60 day storage time at three different periods within the lactation season of the goat. high mean log counts per gram of cheese for aerobic bacteria (7.92-9.56), lactic acid bacteria (7. 78-9.32), gram-negative organisms 5.64-9.67), psychrotrophs (7.90-11. 79) and proteolytic bacteria (7.57-9.36) were found. enterobacteriaceae, coliforms and yeasts were considerably lower. enterobacteriaceae and coliforms in the curd of ch ...	1999	10583688
the purified and functionally reconstituted multidrug transporter lmra of lactococcus lactis mediates the transbilayer movement of specific fluorescent phospholipids.	lactococcus lactis possesses an atp-binding cassette transporter, lmra, which is a homolog of the mammalian multidrug resistance (mdr) p-glycoprotein, and is able to transport a broad range of structurally unrelated amphiphilic drugs. a histidine tag was introduced at the n-terminus of lmra to facilitate purification by nickel affinity chromatography. the histidine-tagged protein was overexpressed in l. lactis using a novel protein expression system for cytotoxic proteins based on the tightly re ...	1999	10587454
phylogenetic analyses of proton-translocating transhydrogenases.	the proton-translocating nicotinamide nucleotide transhydrogenases (th) provide a simple model for understanding chemically coupled transmembrane proton translocation. to further our understanding of th structure-function relationships, we have identified all sequenced homologous of these vectorial enzymes and have conducted sequence comparison studies. the nad-binding domains of th are homologous to bacterial alanine dehydrogenases (adh) and eukaryotic saccharopine dehydrogenases (sdh) as well ...	1999	10587945
synthesis of lactococcin 972, a bacteriocin produced by lactococcus lactis ipla 972, depends on the expression of a plasmid-encoded bicistronic operon.	synthesis of lactococcin 972 is plasmid-encoded. an operon composed of two genes that encode pre-bacteriocin and a putative immunity protein has been identified. the first gene encodes a 91-residue polypeptide that is exported via a sec-dependent system to give the mature 66-aa bacteriocin. the immunity protein is a 563-residue polypeptide with seven potential transmembrane domains. two transcripts were observed from this region: one comprises the whole operon and is synthesized during the expon ...	1999	10589723
analysis of the role of 7 kda cold-shock proteins of lactococcus lactis mg1363 in cryoprotection.	low-temperature adaptation and cryoprotection were studied in the lactic acid bacterium lactococcus lactis mg1363. an approximately 100-fold increased survival after freezing was observed when cells were shocked to 10 degrees c for 4 h compared to mid-exponential-phase cells grown at 30 degrees c, indicating an active protection against freezing. using two-dimensional gel electrophoresis a group of 7 kda cold-induced proteins (csps) was identified that corresponds to a previously described famil ...	1999	10589727
the genetic switch regulating activity of early promoters of the temperate lactococcal bacteriophage tp901-1.	a functional analysis of open reading frame 4 (orf4) and orf5 from the temperate lactococcal phage tp901-1 was performed by mutant and deletion analysis combined with transcriptional studies of the early phage promoters p(r) and p(l). orf4 (180 amino acids) was identified as a phage repressor necessary for repression of both promoters. furthermore, the presence of orf4 confers immunity of the host strain to tp901-1. orf5 (72 amino acids) was found to be able to inhibit repression of the lytic pr ...	1999	10601198
on the microbiological profile of traditional portuguese sourdough.	traditional manufacture of bread from maize has been noted to play important roles from both economic and social standpoints; however, enforcement of increasingly strict hygiene standards requires thorough knowledge of the adventitious microbiota of the departing dough. to this goal, sourdough as well as maize and rye flours from several geographic locations and in two different periods within the agricultural year were assayed for their microbiota in sequential steps of quantification and ident ...	1999	10606146
manipulation of activity and orientation of membrane-reconstituted di-tripeptide transport protein dtpt of lactococcus lactis.	the di-tripeptide transport system (dtpt) of lactococcus lactis was purified to apparent homogeneity by pre-extraction of crude membrane vesicles with octaethylene glycol monodecyl ether (c10e8), followed by solubilization with n-dodecyl-beta-d-maltoside (ddm) and chromatography on a ni-nta resin. the dtpt protein was reconstituted into detergent-destabilized preformed liposomes prepared from e. coli phospholipid/phosphatidylcholine. a variety of detergents were tested for their ability to media ...	1999	10766129
amplified expression and membrane reconstitution of transport proteins.		1999	10830127
distribution of plasmid-borne stress protein genes in streptococcus thermophilus and other lactic acid bacteria.	the presence of heat stress protein genes (hsp) was tested by southern hybridization analysis in total dna extracts from species of the genus streptococcus (47 strains), lactobacillus (34 strains), lactococcus (24 strains), and leuconostoc (5 strains). the biotinylated hsp16.4 probe prepared from an orf2 fragment of per341 (2.8 kb) tested positively with restricted dna extracts of seven streptococcus thermophilus strains and a single strain of lactococcus lactis subsp. cremoris. in all positive ...	1999	9841781
influence of osmolarity and the presence of an osmoprotectant on lactococcus lactis growth and bacteriocin production	growth inhibition of lactococcus lactis provoked by increasing osmolarity is reversed when glycine betaine (gb) or its analogs are added to a defined medium. lacticin 481 production increased sharply with growth medium osmolarity in the absence of osmoprotectant but remained unaffected when gb was supplied in media of increasing osmolarity.	1999	9872793
expression, regulation, and mode of action of the abig abortive infection system of lactococcus lactis subsp. cremoris uc653	the abortive infection system abig is encoded by the lactococcal plasmid pci750. the abig locus (consisting of two genes, abigi and abigii) was examined by northern blot analysis, revealing two transcripts of approximately 2.8 and 1.5 kb which were homologous to the two gene-specific probes. a transcriptional start site was mapped upstream of abigi, and it appeared that the two genes were cotranscribed, resulting in the 2.8-kb transcript. the smaller transcript may be the result of independent t ...	1999	9872803
ap site structural determinants for fpg specific recognition.	the binding of escherichia coli and lactococcus lactis fapy-dna glyosylase (fpg) proteins to dna containing either cyclic or non-cyclic abasic (ap) site analogs was investigated by electrophoretic mobility shift assay (emsa) and by footprinting experiments. we showed that the reduced ap site is the best substrate analog for the e.coli and l.lactis enzymes ( k dapp = 0.26 and 0.5 nm, respectively) as compared with the other analogs tested in this study ( k dapp >2.8 nm). the 1,3-propanediol (pr) ...	1999	9862987
exopolysaccharide biosynthesis in lactococcus lactis nizo b40: functional analysis of the glycosyltransferase genes involved in synthesis of the polysaccharide backbone.	we used homologous and heterologous expression of the glycosyltransferase genes of the lactococcus lactis nizo b40 eps gene cluster to determine the activity and substrate specificities of the encoded enzymes and established the order of assembly of the trisaccharide backbone of the exopolysaccharide repeating unit. epsd links glucose-1-phosphate from udp-glucose to a lipid carrier, epse and epsf link glucose from udp-glucose to lipid-linked glucose, and epsg links galactose from udp-galactose t ...	1999	9864348
histidinol phosphate phosphatase, catalyzing the penultimate step of the histidine biosynthesis pathway, is encoded by ytvp (hisj) in bacillus subtilis.	the deduced product of the bacillus subtilis ytvp gene is similar to that of orf13, a gene of unknown function in the lactococcus lactis histidine biosynthesis operon. a b. subtilis ytvp mutant was auxotrophic for histidine. the only enzyme of the histidine biosynthesis pathway that remained uncharacterized in b. subtilis was histidinol phosphate phosphatase (holpase), catalyzing the penultimate step of this pathway. holpase activity could not be detected in crude extracts of the ytvp mutant, wh ...	1999	10322033
cloning and molecular characterization of the citrate utilization citmcdefgrp cluster of leuconostoc paramesenteroides.	the citmcdefgrp cluster from leuconostoc paramesenteroides involved in citrate utilization was cloned and its nucleotide sequence determined. homology of the inferred gene products with characterized enzymes reveals that citp encodes the citrate permease p, citc the citrate ligase and citdef the subunits of the citrate lyase of leuconostoc. moreover, it suggests that citm encodes a leuconostoc malic enzyme. analysis of citrate consumption by and citrate lyase activity of lc. paramesenteroides j1 ...	1999	10339813
relationship between acid tolerance, cytoplasmic ph, and atp and h+-atpase levels in chemostat cultures of lactococcus lactis.	the acid tolerance response (atr) of chemostat cultures of lactococcus lactis subsp. cremoris ncdo 712 was dependent on the dilution rate and on the extracellular ph (pho). a decrease in either the dilution rate or the pho led to a decrease in the cytoplasmic ph (phi) of the cells, and similar levels of acid tolerance were observed at any specific phi irrespective of whether the phi resulted from manipulation of the growth rate, manipulation of the pho, or both. acid tolerance was also induced b ...	1999	10347003
heterologous protein secretion in lactococcus lactis: a novel antigen delivery system.	lactic acid bacteria (lab) are gram-positive bacteria and are generally regarded as safe (gras) organisms. therefore, lab could be used for heterologous protein secretion and they are good potential candidates as antigen delivery vehicles. to develop such live vaccines, a better control of protein secretion is required. we developed an efficient secretion system in the model lab, lactococcus lactis. staphylococcal nuclease (nuc) was used as the reporter protein. we first observed that the quanti ...	1999	10347754
lacticin 3147 displays activity in buffer against gram-positive bacterial pathogens which appear insensitive in standard plate assays.	lacticin 3147 is a broad-spectrum bacteriocin produced by lactococcus lactis subsp. lactis dpc3147, which has been shown to be active against a range of food-borne bacteria. the reported inhibitory range for lacticin is extended to include methicillin-resistant staphylococcus aureus, vancomycin-resistant enterococcus faecalis, penicillin-resistant pneumococcus, propionibacterium acne and streptococcus mutans. this extended host range is not obvious from traditional agar plate-based methods, but ...	1999	10347889
are horizontal transfers involved in the evolution of the streptococcus thermophilus exopolysaccharide synthesis loci?	a 32.5kb variable locus of the streptococcus thermophilus cnrz368 chromosome, the eps locus, contains 25 orf and seven insertion sequences (is). the putative products of 17 orf are related to proteins involved in the synthesis of polysaccharides in various bacteria. the two distal regions and a small central region of the eps locus are constant and present in all or almost all of the s. thermophilus strains tested. the other regions are variable and present in only some s. thermophilus strains t ...	1999	10375631
purification and characterization of a lysine-p-nitroanilide hydrolase, a broad specificity aminopeptidase, from the cytoplasm of lactococcus lactis subsp. cremoris am2.	a hydrolase activity that cleaves lysyl-p-nitroanilide (lys-pna) has been purified from the cytoplasm of lactococcus lactis subsp. cremoris am2 by chromatography on de52, deae affi-gel blue gel, hydroxyapatite bio-gel htp and phenyl sepharose. the purified aminopeptidase was found to have a native m(r) of 50,000-55,000 by gel filtration chromatography and by fplc gel filtration on superose 12 and to be composed of a single polypeptide chain following sds-page. enzyme activity was almost complete ...	1999	10376245
effects of gene disruptions in the nisin gene cluster of lactococcus lactis on nisin production and producer immunity.	the lantibiotic nisin is produced by several strains of lactococcus lactis subsp. lactis. the chromosomally located gene cluster nisabtciprkfeg is required for biosynthesis, development of immunity, and regulation of gene expression. inframe deletions in the nisb and nist genes, and disruption of nisc by plasmid integration, eliminated nisin production and resulted in a strongly reduced level of immunity of the strains. the transcription of two nisin operons was inactivated in these mutant strai ...	1999	10376839
identification of biosynthetic intermediates of the extracellular polysaccharide viilian in lactococcus lactis subspecies cremoris sbt 0495.	lactococcus lactis subspecies cremoris sbt 0495 produces the phosphopolysaccharide viilian, which consists of the repeating unit beta-d-glucosyl-(1-->4)-(alpha-l-rhamnosyl-(1-->2))-(alpha-d-galac tose-1- phosphoryl-(-->3)-beta-galactosyl-(1-->4)-beta-d-glucose. a lipid extract was prepared from cells in the late exponential phase of growth and was hydrolyzed by hydrochloric acid under mild conditions to split lipid-linked intermediates in the extract into lipid and sugar moieties. both moieties ...	1999	10382265
introduction of the exopolysaccharide gene cluster from streptococcus thermophilus sfi6 into lactococcus lactis mg1363: production and characterization of an altered polysaccharide.	streptococcus thermophilus sfi6 produces an exopolysaccharide (eps) composed of glucose, galactose and n-acetylgalactosamine in the molar ratio of 1:2:1. the genes responsible for the eps biosynthesis have been isolated previously and found to be clustered in a 14.5 kb region encoding 13 genes. transfer of this gene cluster into a non-eps-producing heterologous host, lactococcus lactis mg1363, yielded an eps with a similar high molecular weight, but a different structure from the eps from the na ...	1999	10383768
conversion of lactococcus lactis from homolactic to homoalanine fermentation through metabolic engineering.	we report the engineering of lactococcus lactis to produce the amino acid l-alanine. the primary end product of sugar metabolism in wild-type l. lactis is lactate (homolactic fermentation). the terminal enzymatic reaction (pyruvate + nadh-->l-lactate + nad+) is performed by l-lactate dehydrogenase (l-ldh). we rerouted the carbon flux toward alanine by expressing the bacillus sphaericus alanine dehydrogenase (l-aladh; pyruvate + nadh + nh4+ -->l-alanine + nad+ + h2o). expression of l-aladh in an ...	1999	10385325
study of the possible mechanisms involved in the mucosal immune system activation by lactic acid bacteria.	the induction of a mucosal immune response is not easy due to the development of oral tolerance, but under some conditions, bacteria can activate this immune system. antigens administered orally can interact with m cells of peyer's patches or bind to the epithelial cells. we have demonstrated that certain lactic acid bacteria are able to induce specific secretory immunity, and others will enhance the gut inflammatory immune response. the aim of this work was to establish the reason for these dif ...	1999	10386296
nucleotide sequence of the streptococcin a-ff22 lantibiotic regulon: model for production of the lantibiotic sa-ff22 by strains of streptococcus pyogenes.	streptococcin a-ff22 (sa-ff22) is a type aii linear lantibiotic produced by streptococcus pyogenes strain ff22. sequence analysis of an approximate 10 kb region of dna showed it to contain nine open reading frames arranged in three operons responsible for regulation, biosynthesis and immunity of sa-ff22. this region is organized similarly to the lactococcus lactis lacticin 481 region, however, unlike lacticin 481, a two-component regulatory system is essential for sa-ff22 production. located imm ...	1999	10386366
specificity of lactococcus lactis subsp. cremoris sk11 proteinase, lactocepin iii, in low-water-activity, high-salt-concentration humectant systems and its stability compared with that of lactocepin i	marked changes in the specificity of hydrolysis of alphas1-, beta-, and kappa-caseins by lactocepin iii from lactococcus lactis subsp. cremoris sk11 were found in humectant systems giving the equivalent water activity (aw) and salt concentration of cheddar cheese. correlations were noted between certain peptides produced by the activity of lactocepin iii in the humectant systems and peptides found in cheddar cheese. the stability of lactocepin iii was compared with that of lactocepin i from l. l ...	1999	10388688
nisin production by a mixed-culture system consisting of lactococcus lactis and kluyveromyces marxianus.	to control the ph during antimicrobial peptide (nisin) production by a lactic acid bacterium, lactococcus lactis subsp. lactis (atcc11454), a novel method involving neither addition of alkali nor a separation system such as a ceramic membrane filter and electrodialyzer was developed. a mixed culture of l. lactis and kluyveromyces marxianus, which was isolated from kefir grains, was utilized in the developed system. the interaction between lactate production by l. lactis and its assimilation by k ...	1999	10388714
in vivo nuclear magnetic resonance studies of glycolytic kinetics in lactococcus lactis.	the metabolism of glucose by nongrowing cells of l. lactis strain mg5267 was studied under controlled conditions of ph, temperature, and gas atmosphere (anaerobic and aerobic) using a circulating system coupled to nuclear magnetic resonance (nmr) detection that allowed a noninvasive determination of intracellular pools of intermediate metabolites by 13c-nmr with a time resolution of 30 seconds. in addition, intracellular parameters, such as ph, ntp levels, and concentration of inorganic phosphat ...	1999	10397856
peps from streptococcus thermophilus. a new member of the aminopeptidase t family of thermophilic bacteria.	the proteolytic system of lactic acid bacteria is essential for bacterial growth in milk but also for the development of the organoleptic properties of dairy products. streptococcus thermophilus is widely used in the dairy industry. in comparison with the model lactic acid bacteria lactococcus lactis, s. thermophilus possesses two additional peptidases (an oligopeptidase and the aminopeptidase peps). to understand how s. thermophilus grows in milk, we purified and characterized this aminopeptida ...	1999	10406960
lactococcus lactis contains only one glutamate decarboxylase gene.	glutamate decarboxylase, which is associated with a glutamate-dependent acid-resistance mechanism, was purified from lactococcus lactis subsp. lactis by a three-step procedure. the specific activity was increased about 114-fold with a yield of 16%. the n-terminal amino acid sequence of the enzyme was determined. the gene encoding this enzyme was cloned in escherichia coli, and its nucleotide sequence was determined. the deduced amino acid sequence suggests that the enzyme is produced as a mature ...	1999	10411264
rna and protein catalysis in group ii intron splicing and mobility reactions using purified components.	group ii introns encode proteins with reverse transcriptase activity. these proteins also promote rna splicing (maturase activity) and then, with the excised intron, form a site-specific dna endonuclease that promotes intron mobility by reverse splicing into dna followed by target dna-primed reverse transcription. here, we used an escherichia coli expression system for the lactococcus lactis group ii intron ll.ltrb to show that the intron-encoded protein (ltra) alone is sufficient for maturase a ...	1999	10413481
identification of genes encoding two-component lantibiotic production in staphylococcus aureus c55 and other phage group ii s. aureus strains and demonstration of an association with the exfoliative toxin b gene.	the production of exfoliative toxin b (et-b), but not et-a, was shown to be specifically associated with production of a highly conserved two-component lantibiotic peptide system in phage group ii staphylococcus aureus. two previously studied but incompletely characterized s. aureus bacteriocins, staphylococcins c55 and bacr1, were found to be members of this lantibiotic system, and considerable homology was also found with the two-component lactococcus lactis bacteriocin, lacticin 3147. sacalph ...	1999	10417203
spray-drying of bacteriocin-producing lactic acid bacteria.	cell survival, cellular damage, and antagonistic activity were investigated after spray-drying of four bacteriocin-producing strains of lactic acid bacteria: lactococcus lactis subsp. lactis 140, isolated from natural whey culture and producing a narrow-inhibitory spectrum bacteriocin); l. lactis subsp. lactis g35, isolated from pizza dough and producing nisin; lactobacillus curvatus 32y and lactobacillus sp. 8z, isolated from dry sausages. trials were performed with bacteria suspended in skimme ...	1999	10419271
effects of the addition of enterococcus faecalis in cebreiro cheese manufacture.	ten batches of cebreiro, a fresh or short-ripened acid-curd cheese, produced in the galician mountains (nw spain) were prepared from pasteurized milk inoculated with microorganisms isolated from raw-milk cheese. two control batches were made with a lactococcus lactis subsp. lactis starter; 8 batches were made with the lactococcal starter plus one of eight enterococcus faecalis cultures: 4 e. faecalis var. liquefaciens (eflb) and 4 e. faecalis var. faecalis (effb). whey dry matter in the eflb was ...	1999	10426446
rapid fluorescence assessment of the viability of stressed lactococcus lactis.	the aim of this study was to establish the use of the fluorescent probes carboxyfluorescein (cf) and propidium iodide (pi) for rapid assessment of viability, using lactococcus lactis subsp. lactis ml3 exposed to different stress treatments. the cf labeling indicated the reproductive capacity of mixtures of nontreated cells and cells killed at 70 degrees c very well. however, after treatment up to 60 degrees c the fraction of cf-labeled cells remained high, whereas the survival decreased for cell ...	1999	10427066
a nisin bioassay based on bioluminescence.	a lactococcus lactis subsp. lactis strain that can sense the bacteriocin nisin and transduce the signal into bioluminescence was constructed. by using this strain, a bioassay based on bioluminescence was developed for quantification of nisin, for detection of nisin in milk, and for identification of nisin-producing strains. as little as 0.0125 ng of nisin per ml was detected within 3 h by this bioluminescence assay. this detection limit was lower than in previously described methods.	1999	10427078
expression of the mobm gene of the streptococcal plasmid pmv158 in lactococcus lactis subsp. lactis.	the streptococcal plasmid pmv158 is not auto-transferable, but it can be mobilised between bacteria by the use of functions supplied by plasmids of the pip501/pam beta 1 family. plasmid pmv158 encodes a protein, mobm, which is involved in its mobilisation. this process initiates when mobm specifically cleaves supercoiled pmv158 plasmid dna at the origin of transfer, orit. plasmid pmv158 has been transferred to lactococcus lactis by conjugation aided by plasmid pam beta 1. in the lactococcal host ...	1999	10427723
an aminoacyl-trna synthetase paralog with a catalytic role in histidine biosynthesis.	in addition to their essential catalytic role in protein biosynthesis, aminoacyl-trna synthetases participate in numerous other functions, including regulation of gene expression and amino acid biosynthesis via transamidation pathways. herein, we describe a class of aminoacyl-trna synthetase-like (hisz) proteins based on the catalytic core of the contemporary class ii histidyl-trna synthetase whose members lack aminoacylation activity but are instead essential components of the first enzyme in h ...	1999	10430882
functional insights into pgi2, a cryptic rolling-circle replicating plasmid from bacillus thuringiensis.	detailed functional analysis revealed the modular organization of pgi2, a 9672 bp plasmid from bacillus thuringiensis h1.1 that harbours the 4149 bp transposon tn4430. whereas the pgi2 leading-strand replicon was identified through deletion experiments, sequence comparisons indicated the presence of an ssot-like single-strand origin commonly found among bacillus plasmids. southern hybridization confirmed the existence of ssdna intermediates, but only in the case of plasmid derivatives lacking th ...	1999	10439392