| a placebo-controlled study of the effect of sour milk on blood pressure in hypertensive subjects. | a placebo-controlled study was conducted to test the effect of calpis (calpis food industry co, ltd, tokyo, japan) sour milk, i.e., a milk fermented with a starter containing lactobacillus helveticus and saccharomyces cerevisiae, on the blood pressure of 30 elderly hypertensive patients, most of whom were taking antihypertensive medication. subjects were randomly assigned to two groups. one group ingested daily 95 ml of the sour milk for 8 wk, and the other group ingested the same amount of arti ... | 1996 | 8901799 |
| addition of deoxyribose to guanine and modified dna based by lactobacillus helveticus trans-n-deoxyribosylase. | the use of bacterial trans-n-deoxyribosylase was evaluated as an alternative method for deoxyribosylation in the synthesis of deoxyribonucleosides containing potentially mutagenic adducts. a crude enzyme preparation was isolated from lactobacillus helveticus and compared to escherichia coli purine nucleoside phosphorylase. trans-n-deoxyribosylase was more regioselective than purine nucleoside phosphorylase in the deoxyribosylation of gua at the n9 atom, as compared to n7, as demonstrated by nmr ... | 1996 | 8902269 |
| 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 |
| characterization of a prolinase gene and its product and an adjacent abc transporter gene from lactobacillus helveticus. | a prolinase (pepr) gene was cloned from an industrial lactobacillus helveticus strain (53/7). three clones, hybridizing with a gene probe specific for a peptidase shown to have activity against di- and tripeptides, were detected from a l. helveticus genomic library constructed in escherichia coli. none of the three clones, however, showed enzyme activity against the di- or tripeptide substrates tested. one of the clones, carrying a vector with a 5.5 kb insert, was further characterized by dna se ... | 1996 | 8936308 |
| isolation, purification, and amino acid sequence of lactobin a, one of the two bacteriocins produced by lactobacillus amylovorus lmg p-13139. | lactobacillus amylovorus lmg p-13139, isolated from corn steep liquor, produces two bactericidal peptides with respective estimated molecular masses of 4.5 and 6.0 kda upon denaturing sodium dodecyl sulfatepolyacrylamide gel electrophoresis. the antimicrobial activity detected in the fermentation supernatant fraction of l. amylovorus lmg p-13139 was heat stable (20 min, 121 degrees c), displayed a narrow inhibitory spectrum, and was sensitive to proteinase k, trypsin, and alpha-chymotrypsin but ... | 1997 | 8979334 |
| differential expression of lim homeobox genes among motor neuron subpopulations in the developing chick brain stem. | during development of the chick brain stem, cranial motor neuron subpopulations differentiate at distinct axial levels and extend their axons along specific pathways into the periphery. differences in phenotype and axonal trajectory of these neuronal populations might be governed by the expression of different repertoires of transcription factors. in 2- to 7-day chick embryos, we find that genes of the lim homeobox family are expressed differentially among cranial motor nuclei. whereas islet-1 i ... | 1996 | 9000439 |
| x-prolyl dipeptidyl aminopeptidase gene (pepx) is part of the glnra operon in lactobacillus rhamnosus. | a peptidase gene expressing x-prolyl dipeptidyl aminopeptidase (pepx) activity was cloned from lactobacillus rhamnosus 1/6 by using the chromogenic substrate l-glycyl-l-prolyl-beta-naphthylamide for screening of a genomic library in escherichia coli. the nucleotide sequence of a 3.5-kb hindiii fragment expressing the peptidase activity revealed one complete open reading frame (orf) of 2,391 nucleotides. the 797-amino-acid protein encoded by this orf was shown to be 40, 39, and 36% identical with ... | 2000 | 10613874 |
| purification and molecular characterization of a tripeptidase (pept) from lactobacillus helveticus. | a tripeptidase (pept) from a thermophilic dairy starter strain of lactobacillus helveticus was purified by four chromatographic steps. pept appeared to be a trimeric metallopeptidase with a molecular mass of 150 kda. pept exhibited maximum activity against hydrophobic tripeptides, with the highest activity for met-gly-gly (k(m), 2.6 mm; v(max), 80.2 micromol. min(-1). microg(-1)). some of the hydrophobic dipeptides were slowly hydrolyzed, distinguishing the lactobacillus pept from its counterpar ... | 2000 | 10653753 |
| 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 |
| 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 |
| an operon from lactobacillus helveticus composed of a proline iminopeptidase gene (pepi) and two genes coding for putative members of the abc transporter family of proteins. | a proline iminopeptidase gene (pepi) of an industrial lactobacillus helveticus strain was cloned and found to be organized in an operon-like structure of three open reading frames (orf1, orf2 and orf3). orf1 was preceded by a typical prokaryotic promoter region, and a putative transcription terminator was found downstream of orf3, identified as the pepi gene. using primer-extension analyses, only one transcription start site, upstream of orf1, was identifiable in the predicted operon. although t ... | 1996 | 9004508 |
| immunomodulatory activity of beta-casein permeate medium fermented by lactic acid bacteria. | during fermentation, lactic acid bacteria may be able to release components that possess immunomodulatory activity. this activity was investigated in several culture supernatants arising from lactic acid bacteria cultured in a medium composed primarily of uf permeate of bovine milk; beta-cn was added as the sole protein source. only a lactobacillus helveticus supernatant allowed the modulation (both suppression and enhancement) of lymphocyte proliferation in vitro on human peripheral blood lymph ... | 1996 | 9029350 |
| high pressure inactivation of microorganisms inoculated into ovine milk of different fat contents. | high hydrostatic pressure inactivation of escherichia coli, pseudomonas fluorescens, listeria innocua, staphylococcus aureus, and lactobacillus helveticus were studied. these microorganisms were inoculated at a concentration between 10(7) and 10(8) cfu/ml in ringer solution and in ovine milk adjusted to 0, 6, and 50% fat content to evaluate the baroprotective effect of fat content on inactivation of microorganisms. treatments of pressurization consisted of combinations of pressure (100 to 500 mp ... | 2000 | 10791782 |
| characterization of an arylesterase from lactobacillus helveticus cnrz32. | an esterase gene (esta) was isolated from a previously constructed genomic library of lactobacillus helveticus cnrz32. the esta gene consisted of a 558 bp open reading frame encoding a putative peptide of 21.3 kda. protein sequence homology searches using blast revealed that esta had low amino acid sequence identity with the serine-dependent arylesterases tesi (24%) and etpa (26%) from escherichia coli and vibrio mimicus, respectively. a recombinant esta fusion protein containing a c-terminal si ... | 2000 | 10792515 |
| surface of lactic acid bacteria: relationships between chemical composition and physicochemical properties. | the surface chemical composition and physicochemical properties (hydrophobicity and zeta potential) of two lactic acid bacteria, lactococcus lactis subsp. lactis bv. diacetilactis and lactobacillus helveticus, have been investigated using cells harvested in exponential or stationary growth phase. the surface composition determined by x-ray photoelectron spectroscopy (xps) was converted into a molecular composition in terms of proteins, polysaccharides, and hydrocarbonlike compounds. the concentr ... | 2000 | 10831437 |
| autolysis and related proteolysis in swiss cheese for two lactobacillus helveticus strains. | intracellular peptidases of lactobacillus helveticus may play a major role in the proteolysis of swiss cheeses, provided that they are released through bacterial lysis. experimental swiss cheeses were manufactured on a small scale from thermized and microfiltered milk using as starters (in addition to streptococcus thermophilus and propionibacterium freudenreichii) one of two lb. helveticus strains, itglh1 and itglh77, which undergo lysis to different extents in vitro. all the cheeses were bioch ... | 2000 | 10840680 |
| lactobacillus fornicalis sp. nov., isolated from the posterior fornix of the human vagina. | twelve strains isolated from the posterior fornix fluid of the human vagina were identified as lactobacillus johnsonii, lactobacillus acidophilus, lactobacillus gallinarum and lactobacillus crispatus based on numerical analyses of total soluble cell protein profiles and randomly amplified polymorphic dna (rapd)-pcr banding patterns. five strains grouped with the type strains of lactobacillus gasseri (dsm 20077t) and lactobacillus jensenii (dsm 20557t) at r > or = 0.83 in one protein profile clus ... | 2000 | 10843070 |
| caroteno-protein and exopolysaccharide production by co-cultures of rhodotorula glutinis and lactobacillus helveticus. | the lactose-negative yeast rhodotorula glutinis 22p and the homofermentative lactic acid bacterium lactobacillus helveticus 12a were cultured together in a cheese whey ultrafiltrate containing 42 g l-1 lactose. the chemical composition of the caroteno-protein has been determined. the carotenoid and protein contents are 248 micrograms g-1 dry cells and 48.2% dry weight. carotenoids produced by rhodotorula glutinis 22p have been identified as beta-carotene 15%, torulene 10%, and torularhodin 69%. ... | 1997 | 9172434 |
| molecular cloning and sequence analysis of a gene encoding an extracellular proteinase from lactobacillus helveticus cp790. | a 2.6-kilobase haeiii dna fragment corresponding to an extracellular proteinase gene (prty) was cloned from chromosomal dna of lactobacillus helveticus cp790 in escherichia coli using a pkk223-3 vector. the transformant expressed a 48-kda protein that reacts with monoclonal antibodies specific to the proteinase and seemed to be a pre-proproteinase, but had no proteolytic activity. about 1.6 kilobases of the 2.6-kilobase dna fragment, which contained the complete gene for the proteinase was seque ... | 2000 | 10923793 |
| s-layer gene as a molecular marker for identification of lactobacillus helveticus. | the paper describes two methods that allow rapid and accurate identification of lactobacillus helveticus strains based on the nucleotide sequence of the gene coding for the surface layer (s-layer) protein. the first method is based on a polymerase chain reaction amplification using primers targeting a specific fragment of the s-layer gene. the second method involved a portion of the s-layer gene of l. helveticus as a probe in a hybridisation test. the specificity of these protocols was checked f ... | 2000 | 10930751 |
| molecular genetic characterization of the l-lactate dehydrogenase gene (ldhl) of lactobacillus helveticus and biochemical characterization of the enzyme. | the lactobacillus helveticus l-(+)-lactate dehydrogenase (l-ldh) gene (ldhl) was isolated from a lambda library. the nucleotide sequence of the ldhl gene was determined and shown to have the capacity to encode a protein of 323 amino acids (35.3 kda). the deduced sequence of the 35-kda protein revealed a relatively high degree of identity with other lactobacillar l-ldhs. the highest identity (80.2%) was observed with the lactobacillus casei l-ldh. the sizes and 5' end analyses of ldhl transcripts ... | 1997 | 9212432 |
| biochemistry of s-layers. | during evolution prokaryotes have developed different envelope structures exterior to the cell wall proper. among these surface components are regularly arranged s-layers and capsules. the structural characterization and the detailed chemical analysis of these surface molecules is a prerequisite to understand their biosynthesis and functional role(s) at the molecular level. of particular interest are the glycosylated s-layer proteins which belong to the first prokaryotic glycoproteins ever descr ... | 1997 | 9276927 |
| lactobacillus helveticus lh59 secretes an exopolysaccharide that is identical to the one produced by lactobacillus helveticus tn-4, a presumed spontaneous mutant of lactobacillus helveticus ty1--2. | lactobacillus helveticus lh59 produces a high-molecular-mass exopolysaccharide (> or = 2 x 10(6) da) when cultured in skimmed milk. compositional analysis, methylation analysis and nmr experiments (1h and 13c) recorded from the native polysaccharide as well as from oligosaccharides released by partial acid hydrolysis, allowed the complete structural determination of this polysaccharide, which consists of the following hexasaccharide repeating unit: [symbol: see text] this structure is identical ... | 1997 | 9291572 |
| ripening of cheddar cheese with added attenuated adjunct cultures of lactobacilli. | we made milled curd cheddar cheese with lactococcus starter and an adjunct culture of lactobacillus helveticus i or lactobacillus casei t subjected to different attenuation treatments: freeze shocking (fs), heat shocking (hs), or spray drying (sd). proteolysis during cheese ripening (0 to 6 mo), measured by urea-page and water-soluble nitrogen, indicated only minor differences between control and most adjunct-treated cheeses. however, there were significant differences in the effect of lactobaci ... | 2000 | 10984143 |
| maturation factor for the activation process of an extracellular proteinase in lactobacillus helveticus cp790. | a maturation factor that was needed for activation of an extracellular proteinase was partially purified from lactobacillus helveticus cp790 by deae-sepharose column chromatography, followed by gel filtration using hplc. the protein had the ability to accelerate the conversion of proproteinase to active enzyme but had no proteolytic activity toward casein that had been treated with fluorescein isothiocyanate. the proteinase activities in the proproteinase fraction and the maturation protein frac ... | 1997 | 9313133 |
| a lactobacillus helveticus plasmid detects restriction fragment length polymorphism in different bacterial species. | a small cryptic lactobacillus helveticus plasmid, plbl4, was able to reveal restriction fragment length polymorphism in different bacterial species including lactobacillus species, bacillus species, and escherichia coli when used as a dna probe. the observed polymorphism was a result of the combined hybridization of several microsatellite sequences. the 6-bp sequence (ttgttt) was repeated 12 times, seven of which were concentrated within the region between 1791 and 1997 bp of the plasmid sequenc ... | 2000 | 11034301 |
| antimutagenic effects of milk fermented by lactobacillus helveticus l89 and a protease-deficient derivative. | the antimutagenic effects of whey, acetone extracts, and protein fractions isolated from milk that had been fermented by lactobacillus helveticus l89 were investigated using the mutagen 4-nitroquinoline-n'-oxide in the ames test (salmonella typhimurium ta 100). fermented milk significantly inhibited mutagenesis induced by 4-nitroquinoline-n'-oxide. however, milk fermented by a nonproteolytic variant of the same strain showed no inhibitory effects. results were similar for the whey fractions and ... | 1997 | 9313136 |
| a modified form of a vitamin b12 compound extracted from whey fermented by lactobacillus helveticus. | the content of vitamin b12 in whey was reduced considerably during lactic acid fermentation, which was analogous to the lactic acid fermentation of milk. this apparent b12 decrease in whey was caused by b12 compounds that were unextractable by conventional extraction with potassium cyanide but that could be extracted by sonication and treatment by proteases such as pepsin and papain. forms of the extracted b12 compounds were examined by bioautographies with escherichia coli 215, coupled with cel ... | 1997 | 9406064 |
| lactobacilli carry cryptic genes encoding peptidase-related proteins: characterization of a prolidase gene (pepq) and a related cryptic gene (orfz) from lactobacillus delbrueckii subsp. bulgaricus. | two genes, pepq and orfz, encoding a prolidase and a prolidase-like protein, respectively, were cloned and characterized from lactobacillus delbrueckii subsp. bulgaricus. the identity of the pepq and orfz genes with the lactobacillus delbrueckii subsp. lactis prolidase gene (pepq) was shown to be 98% and 60%, respectively. both pepq and orfz were preceded by a putative promoter region. northern analysis of pepq mrna revealed a 1.1 kb transcript indicating that pepq forms a monocistronic transcri ... | 1997 | 9421914 |
| the s-layer protein of lactobacillus acidophilus atcc 4356: identification and characterisation of domains responsible for s-protein assembly and cell wall binding. | lactobacillus acidophilus, like many other bacteria, harbors a surface layer consisting of a protein (s(a)-protein) of 43 kda. s(a)-protein could be readily extracted and crystallized in vitro into large crystalline patches on lipid monolayers with a net negative charge but not on lipids with a net neutral charge. reconstruction of the s-layer from crystals grown on dioleoylphosphatidylserine indicated an oblique lattice with unit cell dimensions (a=118 a; b=53 a, and gamma=102 degrees ) resembl ... | 2001 | 11124903 |
| classification of lactobacillus helveticus strains by immunological differences in extracellular proteinases. | polyclonal antibodies against an extracellular proteinase of lactobacillus helveticus cp53 were raised. the antibodies reacted with a 170-kda enzyme with activity and a 53-kda protein that seemed to be a degradation product of the 170-kda proteinase from results of immunoblotting. the antibodies reacted also with a 45-kda extracellular proteinase of l. helveticus cp790. however, monoclonal antibodies to the cp790 proteinase did not react with the proteinase of l. helveticus cp53. seventeen strai ... | 1998 | 9692208 |
| survival of lactobacillus helveticus strain cp53 in the human gastrointestinal tract. | a strain of lactobacillus helveticus carrying the cryptic plasmid pcp53 was used for a detailed analysis of the survival and persistence of this organism in the faeces of volunteers administered oral doses of the strain. the cp53 strain had high affinity for caco-2 cells, but displayed low bile acid resistance in vitro. rifampicin-resistant colonies could be reisolated from the faeces of four of seven subjects fed with the rifampicin-resistant cp53 derivative strain. moreover, the recovery of ce ... | 2001 | 11169053 |
| genotypic heterogeneity among lactobacillus helveticus strains isolated from natural cheese starters. | a total of 23 strains of lactobacillus helveticus isolated from natural whey starter cultures for italian hard cheeses and three reference strains were characterized by plasmid profiling, ribotyping and random amplified polymorphic dna (rapd) fingerprinting. the data showed an interesting strain heterogeneity in natural cheese starters, that seemed not only strain-dependent, but also related to the source of isolates. nineteen of the strains tested harboured extrachromosomal elements, whilst 11 ... | 1998 | 9750270 |
| characterization by molecular cloning and sequencing of the gene encoding an aminopeptidase from listeria monocytogenes. | the pepc gene of listeria monocytogenes encodes aminopeptidase c that is predicted to share 72% amino acid sequence similarity and 53% sequence identity with the cysteine aminopeptidase pepc from lactococcus lactis. the gene product also shows strong similarity to aminopeptidase c from streptococcus thermophilus and lactobacillus helveticus, and to a cysteine proteinase/bleomycin hydrolase from saccharomyces cerevisiae. the enzyme from l. monocytogenes displayed broad n-terminal hydrolytic activ ... | 2000 | 11204766 |
| expression of six peptidases from lactobacillus helveticus in lactococcus lactis. | for development of novel starter strains with improved proteolytic properties, the ability of lactococcus lactis to produce lactobacillus helveticus aminopeptidase n (pepn), aminopeptidase c (pepc), x-prolyl dipeptidyl aminopeptidase (pepx), proline iminopeptidase (pepi), prolinase (pepr), and dipeptidase (pepd) was studied by introducing the genes encoding these enzymes into l. lactis mg1363 and its derivatives. according to northern analyses and enzyme activity measurements, the l. helveticus ... | 2001 | 11229915 |
| molecular characterization of a stress-inducible gene from lactobacillus helveticus. | a gene (htra) coding for a stress-inducible htra-like protein from lactobacillus helveticus cnrz32 was cloned, sequenced, and characterized. the deduced amino acid sequence of the gene exhibited 30% identity with the htra protein from escherichia coli; the putative catalytic triad and a pdz domain that characterize the htra family of known bacterial serine proteases were also found in the sequence. expression of the l. helveticus htra gene in a variety of stress conditions was analyzed at the tr ... | 1998 | 9829922 |
| specific identification of lactobacillus helveticus by pcr with pepc, pepn and htra targeted primers. | specific regions in three genes coding for aminopeptidases c and n, and a trypsin-like serine protease were selected as species-specific primer sequences for rapid and reliable identification of lactobacillus helveticus strains. the pcr procedures carried out gave specific 524-, 726- and 918-bp amplificates, with dna isolated from l. helveticus. no pcr product was generated for closely related bacteria. the amplification products were also screened for their species specificity in dot blot hybri ... | 2001 | 11325558 |
| tyrosine and phenylalanine catabolism by lactobacillus cheese flavor adjuncts. | bacterial metabolism of tyr and phe has been associated with the formation of aromatic compounds that impart barny-utensil and floral off-flavors in cheese. in an effort to identify possible mechanisms for the origin of these compounds in cheddar cheese, we investigated tyr and phe catabolism by lactobacillus casei and lactobacillus helveticus cheese flavor adjuncts under simulated cheddar cheese-ripening (ph 5.2, 4% nacl, 15 degrees c, no sugar) conditions. enzyme assays of cell-free extracts i ... | 2001 | 11384026 |
| effectiveness of chemometric techniques in discrimination of lactobacillus helveticus biotypes from natural dairy starter cultures on the basis of phenotypic characteristics | lactobacillus helveticus is the dominant organism in natural starter cultures used for the production of typical italian cheeses. in this study, 74 l. helveticus strains, isolated from grana and provolone cheese natural whey starters, were distinguished with respect to their origin by using both cell wall protein profiles and chemometric evaluation of some phenotypic parameters, such as the ability to acidify cultures and the presence of nonspecific proteolytic and peptidase activities. cell wal ... | 1999 | 10103235 |
| partial characterization of a bacteriocin produced by lactobacillus helveticus. | to investigate the antimicrobial activity of a strain of lactobacillus helveticus. | 2001 | 11472525 |
| potential of conjugal transfer as a strategy for the introduction of recombinant genetic material into strains of lactobacillus helveticus | cointegrates generated between a plasmid pip501 deletion derivative (pva797) and nonconjugative shuttle vector psa3 were confirmed as capable of exconjugation from lactococci into a range of strains of lactobacillus helveticus with the concomitant expression of a recombinant gene. the plasmid cointegrate that was formed appeared to be segregationally stable at 37 degrees c in some host strains. in all strains, however, the plasmid became increasingly unstable as the incubation temperature was ra ... | 1999 | 10223978 |
| sensitivity of staphylococcus aureus and lactobacillus helveticus in ovine milk subjected to high hydrostatic pressure. | ovine milk, standardized to 6% fat, was inoculated with staphylococcus aureus cect 534 and lactobacillus helveticus cect 414 at a concentration of 10(7) cfu/ml and treated by high hydrostatic pressure. treatments consisted of combinations of pressure (200, 300, 400, 450, and 500 mpa), temperature (2, 10, 25, and 50 degrees c), and time (5, 10, and 15 min). staphylococcus aureus was highly resistant to pressure; only pressurizations at 50 degrees c of 500 mpa for 15 min achieved reductions of > o ... | 1999 | 10386295 |
| purification and characterization of an antihypertensive peptide from a yogurt-like product fermented by lactobacillus helveticus cpn4. | whey peptides in a yogurt-like product fermented by lactobacillus helveticus cpn4 were fractionated by a sep-pak c-18 cartridge followed by two-step reverse-phase hplc. the antihypertensive activity was measured by systolic blood pressure in spontaneously hypertensive rats after oral administration of each fraction. five major peptides in the final fraction were further purified by reverse-phase hplc and were measured for these antihypertensive activities in spontaneously hypertensive rats. the ... | 1999 | 10416158 |
| heterofermentative pattern and exopolysaccharide production by lactobacillus helveticus atcc 15807 in response to environmental ph. | the objective of this work was to evaluate the fermentation pattern of and the exopolysaccharide (eps) production by lactobacillus helveticus atcc 15807 in milk batch cultures under controlled ph (4.5, 5.0 and 6.2). | 2001 | 11722662 |
| dna cloning in lactobacillus helveticus by the exconjugation of recombinant mob-containing plasmid constructs from strains of transformable lactic acid bacteria. | a system developed for the genetic transfer of plasmids between strains of nontransformable bacteria (p. langella, y. le loir, s. d. ehrlich and a. gruss, 1993, j. bacteriol., 175, 5806-5813) by the specific inclusion of a mobilization (mob) region into a nonconjugative shuttle vector was used successfully to deliver the genetic determinants for beta-glucanase, beta-glucuronidase, and green fluorescent protein to lactobacillus helveticus. expression of two of the genes could be detected in the n ... | 2001 | 11735368 |
| genetic characterization of a cell envelope-associated proteinase from lactobacillus helveticus cnrz32. | a cell envelope-associated proteinase gene (prth) was identified in lactobacillus helveticus cnrz32. the prth gene encodes a protein of 1,849 amino acids and with a predicted molecular mass of 204 kda. the deduced amino acid sequence of the prth product has significant identity (45%) to that of the lactococcal prtp proteinases. southern blot analysis indicates that prth is not broadly distributed within l. helveticus. a prth deletion mutant of cnrz32 was constructed to evaluate the physiological ... | 1999 | 10419958 |
| survival of lactobacillus helveticus entrapped in ca-alginate in relation to water content, storage and rehydration. | lactobacillus helveticus cnrz 303 entrapped in ca-alginate gel beads was investigated for improved survival and stability during fluidized-bed drying, storage and rehydration. addition of protective solutes was very important. studies of the conditions showed that inactivation of entrapped l. helveticus started when the water content exceeded 0.3-0.4 g h2o (g dry wt)-1 for adonitol, glycerol and reconstituted non fat milk solids (nfsm). with ringer's solution (control) and betaine, the fall in v ... | 1999 | 10510483 |
| extracellular arginine aminopeptidase from streptococcus gordonii fss2. | streptococcus gordonii is a primary etiological agent in the development of subacute bacterial endocarditis (sbe), producing thrombus formation and tissue damage on the surfaces of heart valves. this is ironic, considering its normal role as a benign inhabitant of the oral microflora. however, strain fss2 of s. gordonii has been found to produce several extracellular aminopeptidase- and fibrinogen-degrading activities during growth in a ph-controlled batch culture. in this report, we describe th ... | 2002 | 11796618 |
| 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 |
| an x-prolyl dipeptidyl aminopeptidase from lactococcus lactis: cloning, expression in escherichia coli, and application for removal of n-terminal pro-pro from recombinant proteins. | a novel pepx gene was cloned from isolated dna of lactococcus lactis by pcr. the deduced amino acid sequence of the 89-kda protein showed 94, 93, 65, and 44% identity with the pepx protein from lactococcus lactis subsp. cremoris, lactococcus lactis subsp. lactis, lactobacillus delbruecki subsp. bulgaricus, and lactobacillus helveticus, respectively, and contained a serine protease g-k-s-y-l-g consensus motif. the pepx gene has been cloned into pet17b and was expressed at a high level in escheric ... | 2002 | 11922771 |
| stability of species composition of fecal bifidobacteria in human subjects during fermented milk administration. | bifidobacteria play important roles in human health. however, the influence of exogenous factors on species composition of fecal bifidobacteria is still unclear. the objective of this study was to investigate the effects of fermented milk administration on the species composition of fecal bifidobacteria by molecular biological methods. fermented milk containing lactobacillus helveticus was given to seven healthy subjects, and the probiotic effect on human fecal microflora was demonstrated as a s ... | 2002 | 11927989 |
| effect of protective solutes on leakage from and survival of immobilized lactobacillus subjected to drying, storage and rehydration | when lactic acid bacteria are used industrially as fermentation starters it is important to obtain stable and highly viable bacterial cultures. six strains of lactobacillus encapsulated in ca-alginate gel beads were investigated to determine whether dehydration, storage and rehydration may inflict injury. a negative relationship between leakage of lactate dehydrogenase and survival rates was found. mesophilic lactobacilli showed only negligible leakage compared with thermophilic strains when deh ... | 1999 | 10540246 |
| complete sequence of plasmid plh1 from lactobacillus helveticus atcc15009: analysis reveals the presence of regions homologous to other native plasmids from the host strain. | the complete sequence for plasmid plh1 from lactobacillus helveticus atcc15009 has been determined. analysis of the 19,360-bp primary sequence revealed a putative replication origin and initiation protein, information that could provide the basis for the construction of cloning vectors for l. helveticus. evidence that plh1 is theta-replicating could be deduced from the plasmid size, from the homology to the replication protein of the bacillus natto theta-replicating plasmid pls32, and from the i ... | 1999 | 10545264 |
| autolytic phenotype of lactococcus lactis strains isolated from traditional tunisian dairy products. | to evaluate the autolytic properties of lactococcus lactis strains isolated from artisan tunisian dairy products, their peptidoglycan hydrolase content and their activity spectrum. | 2002 | 11972683 |
| recombinant lactococcus starters as a potential source of additional peptidolytic activity in cheese ripening. | the aim of this study was to modulate the lactococcal proteolytic system for enhancement of the cheese ripening process. | 2002 | 12010556 |
| growth of facultatively heterofermentative lactobacilli on starter cell suspensions. | the growth of facultatively heterofermentative lactobacilli (fhl) on cell suspensions of the homofermentative lactobacillus helveticus was investigated. osmotic lysis of l. helveticus led to a significant increase of ribose. it decreased steadily in parallel with the growth of fhl, strongly suggesting that the bacteria used ribose as a growth substrate. | 1999 | 10584024 |
| comparison of simple neural networks and nonlinear regression models for descriptive modeling of lactobacillus helveticus growth in ph-controlled batch cultures. | a set of 20 lactobacillus helveticus growth curves was obtained from ph-controlled batch cultures with different ph setpoints, whey permeate and yeast extract concentrations. to find the best descriptive model of the biomass concentration versus time (y = x(t)) growth curve, fitting results of a large number of models were compared with statistical and approximate methods. models studied included simple neural networks, reparameterized logistic, gompertz, richards, schnute, weibull, and morgan-m ... | 2000 | 10713218 |
| molecular diversity within lactobacillus helveticus as revealed by genotypic characterization. | lactobacillus helveticus is a homofermentative thermophilic lactic acid bacterium that is used in the manufacture of swiss type and long-ripened italian cheeses, such as emmental, grana, and provolone cheeses. substantial differences in several technologically important characteristics are found among l. helveticus strains isolated from natural dairy starter cultures. in the present study we investigated the genotypic diversity of 74 strains isolated from different dairy cultures used for manufa ... | 2000 | 10742197 |
| a polyphasic approach to highlight genotypic and phenotypic diversities of lactobacillus helveticus strains isolated from dairy starter cultures and cheeses. | in the present work, 67 strains of lactobacillus helveticus isolated from whey starter cultures and cheeses were identified and grouped by genotypic and phenotypic methods. strains were identified by sugar fermentation pattern, by cell-wall protein profile, and by probe hybridisation. phenotypic diversity was evaluated by a chemometric model taking into account biochemical characteristics (i.e. acidifying and peptidase activities) of technological interest. genotypic diversity was evidenced by r ... | 2002 | 12047105 |
| biochemical and molecular characterization of pepr, a dipeptidase, from lactobacillus helveticus cnrz32. | a dipeptidase with prolinase activity from lactobacillus helveticus cnrz32, which was designated pepr, was purified to gel electrophoretic homogeneity and characterized. the nh2-terminal amino acid sequence of the purified protein had 96% identity to the deduced nh2-terminal amino acid sequence of the pepr gene, which was previously designated peppn, from l. helveticus cnrz32. the purified enzyme hydrolyzed pro-met, thr-leu, and ser-phe as well as dipeptides containing neutral, nonpolar amino ac ... | 1997 | 9292995 |
| nutritional requirements and nitrogen-dependent regulation of proteinase activity of lactobacillus helveticus crl 1062. | the nutritional requirements of lactobacillus helveticus crl 1062 were determined with a simplified chemically defined medium (scdm) and compared with those of l. helveticus crl 974 (atcc 15009). both strains were found to be prototrophic for alanine, glycine, asparagine, glutamine, and cysteine. in addition, crl 1062 also showed prototrophy for lysine and serine. the microorganisms also required riboflavin, calcium pantothenate, pyridoxal, nicotinic acid, and uracil for growth in liquid scdm. t ... | 2000 | 11097908 |
| cardiovascular effects of fermented milk containing angiotensin-converting enzyme inhibitors evaluated in permanently catheterized, spontaneously hypertensive rats. | in this study, two strains of lactobacillus helveticus were used to produce fermented milk rich in angiotensin-converting enzyme (ace) inhibitors. in vitro tests revealed that the two milks contained competitive inhibitors of ace in amounts comparable to what has been obtained in previously reported studies. the two milks were administered by gavage to spontaneously hypertensive rats that had had a permanent aortic catheter inserted through the left arteria carotis, and mean arterial blood press ... | 2002 | 12089043 |
| rapid and sensitive detection method of a bacterium by using a gfp reporter phage. | a rapid, sensitive, and convenient method for detecting a specific bacterium was developed by using a gfp phage. here we describe a model system that utilizes the temperate escherichia coli-restricted bacteriophage lambda, which was genetically modified to express a reporter gene for gfp to identify the colon bacillus e. coli in the specimen. e. coli infected with gfp phage was detected by gfp fluorescence after 4-6 hr of incubation. the results show that a few bacteria in a specimen can be dete ... | 2002 | 12153113 |
| a food-grade cloning vector for lactic acid bacteria based on the nisin immunity gene nisi. | a new food-grade cloning vector for lactic acid bacteria was constructed using the nisin immunity gene nisi as a selection marker. the food-grade plasmid, pleb 590, was constructed entirely of lactococcal dna: the psh 71 replicon, the nisi gene, and the constitutive promoter p45 for nisi expression. electroporation into lactococcus lactis mg 1614 with 60 international units (iu) nisin/ml selection yielded approximately 10(5) transformants/ micro g dna. mg 1614 carrying pleb 590 was shown to be a ... | 2002 | 12172611 |
| bacterial membrane injuries induced by lactacin f and nisin. | the combined action of nisin and lactacin f, two bacteriocins produced by lactic acid bacteria, is additive. in this report, the basis of this effect is examined. channels formed by lactacin f were studied by experiments using planar lipid bilayers, and bactericidal effects were analyzed by flow cytometry. lactacin f produced pores with a conductance of 1 ns in black lipid bilayers in 1 mm kci at 10 mv at 20 degrees c. pore formation was strongly dependent on voltage. although lactacin f formed ... | 2002 | 12180783 |
| hydrolysis of sequenced beta-casein peptides provides new insight into peptidase activity from thermophilic lactic acid bacteria and highlights intrinsic resistance of phosphopeptides. | the peptidases of thermophilic lactic acid bacteria have a key role in the proteolysis of swiss cheeses during warm room ripening. to compare their peptidase activities toward a dairy substrate, a tryptic/chymotryptic hydrolysate of purified beta-casein was used. thirty-four peptides from 3 to 35 amino acids, including three phosphorylated peptides, constitute the beta-casein hydrolysate, as shown by tandem mass spectrometry. cell extracts prepared from lactobacillus helveticus itg lh1, itg lh77 ... | 2000 | 11097915 |
| structure of a viscous exopolysaccharide produced by lactobacillus helveticus k16. | a viscous extracellular polysaccharide produced by lactobacillus helveticus k16 has been investigated. sugar and methylation analysis, 1h and 13c nmr spectroscopy revealed that the polysaccharide is composed of a hexasaccharide repeating unit. the sequence of sugar residues was determined by use of two-dimensional nuclear overhauser effect spectroscopy and heteronuclear multiple bond connectivity experiments. the structure of the repeating unit of the exopolysaccharide from l. helveticus k16 is ... | 2000 | 11117331 |
| anti-hypertensive activity of fermented dairy products containing biogenic peptides. | a considerable amount of research has been conducted to study the health benefits of fermented milks. one possible mechanism for the beneficial effects is the involvement of biogenic compounds, which are produced by the action of microorganisms and make the products directly beneficial without the need for live bacteria. research on the health effects of a pasteurized sour milk, which is fermented by a starter culture containing lactobacillus helveticus as the predominant microorganism, indicate ... | 2002 | 12369200 |
| genetic diversity in swiss cheese starter cultures assessed by pulsed field gel electrophoresis and arbitrarily primed pcr. | to assess intraspecific genetic heterogeneity among commercial swiss cheese starter culture strains of lactobacillus helveticus, streptococcus thermophilus and propionibacterium freudenreichii and to compare the efficacy of two genetic typing methods. | 2002 | 12390494 |
| molecular cloning and expression of the nucleoside deoxyribosyltransferase-ii gene from lactobacillus helveticus. | nucleoside deoxyribosyltransferase-ii, which catalyzes transfer of glycosyl residues from a donor deoxynucleoside to an acceptor base, was purified from lactobacillus helveticus and its gene was cloned. analysis of the nucleotide sequence showed the presence of a 474-nucleotide open reading frame encoding a protein of 158 amino acids with a molecular weight of 18,317. the active enzyme can be produced in large quantities in e. coli cells using the cloned gene. | 2000 | 11129605 |
| overexpression of peptidases in lactococcus and evaluation of their release from leaky cells. | walker and klaenhammer (2001) developed a novel expression system in lactococcus lactis that facilitated the release of beta-galactosidase (117 kda monomer) without the need for secretion or export signals. the system is based on the controlled expression of integrated prophage holin and lysin cassettes via a lactococcal bacteriophage phi31 transcriptional activator (tac31a) that resides on a high-copy plasmid. approximately 85% of beta-galactosidase activity was detected in the supernatant of l ... | 2002 | 12416795 |
| production of pyroglutamic acid by thermophilic lactic acid bacteria in hard-cooked mini-cheeses. | pyroglutamic acid is present in high amounts (0.5g/ 100g) in many cheese varieties-and particularly in extensively ripened italian cheeses such as grana padano and parmigiano reggiano. an in vivo model system for cooked mini-cheese production and ripening acceleration was set up to demonstrate the ability of thermophilic lactic acid bacteria, used as a starter, to produce pyroglutamic acid (pglu). in mini-cheeses stored at 38 and 30 degrees c for up to 45 d, all starters tested produced differen ... | 2002 | 12416800 |
| molecular discrimination of lactobacilli used as starter and probiotic cultures by amplified ribosomal dna restriction analysis. | lactic acid bacteria such as lactobacillus helveticus, l. delbrueckii subsp. delbrueckii, l. delbrueckii subsp. lactis, l. delbrueckii subsp. bulgaricus, l. acidophilus, and l. casei related taxa which are widely used as starter or probiotic cultures can be identified by amplified ribosomal dna restriction analysis (ardra). the genetic discrimination of the related species belonging to these groups was first obtained by pcr amplifications by using group-specific or species-specific 16s rdna prim ... | 2001 | 11178730 |
| early lysis of lactobacillus helveticus cnrz 303 in swiss cheese is not prophage-related. | lactobacillus helveticus is mainly used as starter in swiss-type cheeses. often, lysogenic strains are eliminated because of the risk of early lysis and acidification failure due to phage expression. on the other hand, l. helveticus lysis was shown to positively influence cheese proteolysis during ripening. in order to better assess the relationship between lysis and lysogeny, a prophage-cured derivative of l. helveticus cnrz 303 was isolated (lh 303-g11) and relysogenised (lh 303-g11r), as demo ... | 2003 | 12457589 |
| isolation and characterization of a slowly milk-coagulating variant of lactobacillus helveticus deficient in purine biosynthesis. | a slowly milk-coagulating variant (fmc(-)) of lactobacillus helveticus crl 1062, designated s1, was isolated and characterized. strain s1 possessed all the known essential components required to utilize casein as a nitrogen source, which include functional proteinase and peptidase activities as well as functional amino acid, di- and tripeptide, and oligopeptide transport systems. the amino acid requirements of strain s1 were similar to those of the parental strain. however, on a purine-free, che ... | 2001 | 11282642 |
| batch cultures of supplemented whey permeate using lactobacillus helveticus: unstructured model for biomass formation, substrate consumption and lactic acid production. | the luedeking and piret expression can not account for the cessation of production observed at the end of batch; so an empiric term has been previously added to this equation which accounted in a global way for possible substrate limitations. in the model developed in this work, a carbon substrate limitation appeared explicitly in the production expression. assuming a sigmoidal variation with time of specific growth rate previously validated, the new production model matched well the entire expe ... | 2001 | 11397465 |
| efficient mechanical disruption of lactobacillus helveticus, lactococcus lactis and propionibacterium freudenreichii by a new high-pressure homogenizer and recovery of intracellular aminotransferase activity. | microbiological studies often involve bacterial cell fractionation, which is known to be difficult for gram-positive as compared to gram-negative bacteria. our purpose was to test the breaking efficiency of a new high-pressure pilot homogenizer for three gram-positive species involved in dairy technology and to assess the activity of an intracellular aminotransferase. varied pressures (50, 100 and 200 mpa) were applied to concentrated bacterial suspensions (1.2 mg dry weight/ml) of lactobacillus ... | 2003 | 12545379 |
| identification and characterization of lactobacillus helveticus pepo2, an endopeptidase with post-proline specificity. | a post-proline endopeptidase (pepo2) was detected in cell extracts from a genomic library of lactobacillus helveticus cnrz32 by using the synthetic substrate n-acetyl-beta-casein-(f203-209)-rho-nitroanilide in a coupled reaction with aminopeptidase n. isolates with activity for this substrate contained plasmids with visually indistinguishable restriction profiles. nucleotide sequence analysis revealed a 1,947-bp open reading frame, designated pepo2, encoding a putative 71.4-kda protein. analysis ... | 2003 | 12571057 |
| hydrolysis of casein-derived peptides alpha(s1)-casein(f1-9) and beta-casein(f193-209) by lactobacillus helveticus peptidase deletion mutants indicates the presence of a previously undetected endopeptidase. | peptides derived from hydrolysis of alpha(s1)-casein(f1-9) [alpha(s1)-cn(f1-9)] and beta-cn(f193-209) with cell extracts of lactobacillus helveticus cnrz32 and single-peptidase mutants (delta pepc, delta pepe, delta pepn, delta pepo, and delta pepx) were isolated by using reverse-phase high-performance liquid chromatography and were characterized by mass spectrometry. the peptides identified suggest that there was activity of an endopeptidase, distinct from previously identified endopeptidases ( ... | 2003 | 12571058 |
| autolytic activity and pediocin-induced lysis in pediococcus acidilactici and pediococcus pentosaceus strains. | to evaluate the autolytic phenotype of pediococcus acidilactici and p. pentosaceus, the peptidoglycan hydrolases content and the effect of pediocin ach/pa-1 and autolysins on cell lysis. | 2003 | 12631191 |
| the impact of fermentation and in vitro digestion on the formation of angiotensin-i-converting enzyme inhibitory activity from pea and whey protein. | pea and whey protein were fermented by lactobacillus helveticus and saccharomyces cerevisiae in monoculture and in combination at 28 and 37 degrees c in order to release angiotensin-i-converting enzyme (ace) inhibitory peptides. the fermentation products were subjected to in vitro gastrointestinal digestion, and the digests of nonfermented samples served as controls. after fermentation, the ace inhibitory activity (%) increased by 18 to 30% for all treatments, except for the fermentations of whe ... | 2003 | 12647949 |
| alteration in cellular fatty acid composition as a response to salt, acid, oxidative and thermal stresses in lactobacillus helveticus. | the fundamental question in this study is concerned with whether the increase of unsaturated fatty acids in the cell membrane is a general response of certain thermotolerant strains or species when exposed to superoptimal temperatures, and in combination with other stresses, especially oxidative stress. a strain of lactobacillus helveticus, a species widely used as a starter in the dairy industry and able to tolerate high temperature and nacl concentrations as well as acidic conditions, was chos ... | 2001 | 11496002 |
| conversion of amino acids into aroma compounds by cell-free extracts of lactobacillus helveticus. | lactobacillus helveticus is an essential starter in swiss-type cheeses such as emmental. this study was to determine whether cell-free extracts of lact. helveticus were able to convert free amino acids into neutral volatile aroma compounds at the ph and temperature occurring in cheese. | 2001 | 11556904 |
| influence of adjunct cultures on ripening of reduced fat edam cheeses. | the influence of four adjunct cultures [brevibacterium linens (bl2), lactococcus lactis ssp. diacetylactis, lactobacillus helveticus (lh212), and lactobacillus reuteri (atcc 23272)] on chemical and sensory characteristics of reduced fat edam cheese was studied. the aminopeptidase activity of lactococcus lactis ssp. diacetylactis was higher than that of lactobacillus helveticus, lactobacillus reuteri, and brevibacterium linens, respectively. mean percent fat and moisture contents of reduced fat c ... | 2001 | 11699441 |
| three new insertion sequence elements isldl2, isldl3, and isldl4 in lactobacillus delbrueckii: isolation, molecular characterization, and potential use for strain identification. | a group of new insertion sequence (is) elements, isldl2, isldl3, and isldl4, from lactobacillus delbrueckii subsp. lactis atcc 15808 was isolated, characterized, and used for strain identification together with isldl1, recently characterized as an l. delbrueckii is element belonging to the isl3 family. isldl2 was 1367 bp in size and had a 24 bp ir and an 8 bp dr. the single orf of isldl2 encoded a protein of 392 aa similar to transposases of the is256 family. isldl3 had a single orf encoding a p ... | 2003 | 12749837 |
| modeling of the structure in aqueous solution of the exopolysaccharide produced by lactobacillus helveticus 766. | a method is described for constructing a conformational model in water of a heteropolysaccharide built up from repeating units, and is applied to the exopolysaccharide produced by lactobacillus helveticus 766. the molecular modeling method is based on energy minima, obtained from molecular mechanics calculations of each of the constituting disaccharide fragments of the repeating unit in vacuo, as starting points. subsequently, adaptive umbrella sampling of the potential of mean force is applied ... | 2002 | 11754349 |
| lactic acid bacteria: inhibition of angiotensin converting enzyme in vitro and in vivo. | a total of 26 strains of wild-type lactic acid bacteria, mainly belonging to lactococcus lactis and lactobacillus helveticus, were assayed in vitro for their ability to produce a milk fermentate with inhibitory activity towards angiotensin converting enzyme (ace). it was clear that the test strains in this study, in general, produce inhibitory substances in varying amounts. using a spectrophotometric assay based on amino group derivatization with ortho-phthaldialdehyde as a measure of relative p ... | 2003 | 12755477 |
| unusual organization for lactose and galactose gene clusters in lactobacillus helveticus. | the nucleotide sequences of the lactobacillus helveticus lactose utilization genes were determined, and these genes were located and oriented relative to one another. the laclm genes (encoding the beta-galactosidase protein) were in a divergent orientation compared to lacr (regulatory gene) and lacs (lactose transporter). downstream from lacm was an open reading frame (gale) encoding a udp-galactose 4 epimerase, and the open reading frame had the same orientation as lacm. the lacr gene was separ ... | 2003 | 12788721 |
| identification of a gene cluster for the mevalonate pathway in lactobacillus helveticus. | three lactobacillus helveticus 53/7 genes essential for the biosynthesis of isopentenyl diphosphate and the gene coding for a putative carotenoid biosynthesis protein were for the first time identified from lactic acid bacteria. the deduced amino acid sequences of the mevalonate pathway gene products share significant identity with corresponding proteins of a few gram-positive cocci and streptomyces species. | 2001 | 11762194 |
| enzymatic synthesis of 2'-deoxyguanosine with nucleoside deoxyribosyltransferase-ii. | nucleoside deoxyribosyltransferase-ii (ndrt-ii) of lactobacillus helveticus, which catalyzes the transfer of a glycosyl residue from a donor deoxyribonucleoside to an acceptor base, has a broad specificity for the acceptor bases. six-substituted purines were found to be substrates as acceptor bases for ndrt-ii. using this property of the enzyme, we established a practical procedure for enzymatic synthesis of 2'-deoxyguanosine (dguo), consisting of the transglycosylation from thymidine to 6-subst ... | 2003 | 12834275 |
| functional cloning, heterologous expression, and purification of two different n-deoxyribosyltransferases from lactobacillus helveticus. | lactobacillus helveticus contains two types of n-deoxyribosyltransferases: drtase i catalyzes the transfer of 2'-deoxyribose between purine bases exclusively whereas drtase ii is able to transfer the 2'-deoxyribose between two pyrimidine or between pyrimidine and purine bases. an escherichia coli strain, auxotrophic for guanine and unable to use deoxyguanosine as source of guanine, was constructed to clone the corresponding genes. by screening a genomic bank for the production of guanine, the l. ... | 2002 | 11836245 |
| biodiversity in lactobacillus helveticus strains present in natural whey starter used for parmigiano reggiano cheese. | lactobacillus helveticus is the dominant microflora of the natural whey starters used for parmigiano reggiano cheese making. the aim of this work was to study the biodiversity of different strains of lact. helveticus present in six cultures and to compare them with strains of the same species previously isolated from natural whey cultures used for grana padano and provolone cheeses. | 2003 | 12911693 |
| synthetic peptides as substrate for assaying the proteolytic activity of lactobacillus helveticus. | four lactobacillus helveticus strains were studied for proteolytic capacity and general aminopeptidase (ap) and x-pro dipeptidyl aminopeptidase (dap) activity. the rate of hydrolysis and the activity against synthetic substrates with n-terminal residues of arg, lys, leu, glu or pro, varied markedly among the strains. the x-pro dap activity was consistently high. the crude cell-wall and cytoplasm extracts from strain lb. helveticus islc59 were analysed thoroughly for their proteolysis ability by ... | 2003 | 12916827 |
| growth and morphology of thermophilic dairy starters in alginate beads. | the aim of this research was to produce concentrated biomasses of thermophilic lactic starters using immobilized cell technology (ict). fermentations were carried out in milk using ph control with cells microentrapped in alginate beads. in the ict fermentations, beads represented 17% of the weight. some assays were carried out with free cells without ph control, in order to compare the ict populations with those of classical starters. with streptococcus thermophilus, overall populations in the f ... | 2003 | 12949701 |
| angiotensin i-converting-enzyme-inhibitory and antibacterial peptides from lactobacillus helveticus pr4 proteinase-hydrolyzed caseins of milk from six species. | sodium caseinates prepared from bovine, sheep, goat, pig, buffalo or human milk were hydrolyzed by a partially purified proteinase of lactobacillus helveticus pr4. peptides in each hydrolysate were fractionated by reversed-phase fast-protein liquid chromatography. the fractions which showed the highest angiotensin i-converting-enzyme (ace)-inhibitory or antibacterial activity were sequenced by mass spectrum and edman degradation analyses. various ace-inhibitory peptides were found in the hydroly ... | 2003 | 12957917 |
| immunomodulating effects of milks fermented by lactobacillus helveticus and its non-proteolytic variant. | the effect of milks fermented by lactobacillus helveticus and its non-proteolytic variant on mucosal and tumoral immunity was studied. milks fermented by lb. helveticus wild type or its non-proteolytic variant were administered orally to mice for different periods (3, 5 and 7 d). the immune response was assessed by analysing the activity of the peritoneal macrophages, the number of cells secreting iga associated with the gut-associated lymphoid tissue and with the bronchial-associated lymphoid t ... | 2001 | 11928956 |
| pantothenylcysteine, a precursor of pantetheine in lactobacillus helveticus. | | 1957 | 13438850 |
| lactobacillus helveticus. | | 1957 | 13439152 |
| colicine k. iii. the immunological properties of a substance having colicine k activity. | by immunological means it has been shown that colicine k is associated with the o antigen of the colicinogenic bacillus e. coli k(235) l(+)oc(+). the colicine k-o antigen complex elicits the formation of at least two types of antibodies, one a precipitin, the other a colicine-neutralizing antibody. the first precipitates colicine k without neutralizing it, the second neutralizes the colicine without precipitating it. unlike the purified colicine k complex, the colicine protein component of the o ... | 1958 | 13587854 |
| structural elucidation of the viscous exopolysaccharide produced by lactobacillus helveticus lb161. | a viscous extracellular polysaccharide produced by lactobacillus helveticus lb161 isolated from raw milk has been investigated. sugar and methylation analysis, and 1h and 13c nmr spectroscopy revealed that the polysaccharide is composed of a heptasaccharide repeating unit. the sequence of sugar residues was determined by use of two-dimensional nuclear overhauser effect spectroscopy and heteronuclear multiple bond connectivity experiments. the structure of the repeating unit of the exopolysacchar ... | 2000 | 10877094 |