| lactostrepcins--acid bacteriocins produced by lactic streptococci. | all 47 non-nisin producing strains of streptococcus lactis and 12/13 strains of str. lactis subsp. diacetylactis examined produced bacteriocins, for which the term lactostrepcins is suggested. seven strains of str. cremoris examined produced no bacteriocins active against 3 lactic streptococci strains used as indicators. the strains examined were divided into 3 groups: i, those producing lactostrepcins active against only one streptomycin resistant mutant of str. lactis 60 indicator strain; ii, ... | 1978 | 27542 |
| nucleoside deoxyribosyltransferase-ii from lactobacillus helveticus substrate specificity studied. pyrimidine bases as acceptors. | the nucleoside deoxyribosyltransferase (nucleoside:purine (pyrimidine) deoxyribosyltransferase, ec 2.4.2.6) fraction catalyzing specifically the transfer of the deoxyribosyl moiety from a purine (or a pyrimidine) to a pyrimidine (or a purine) exhibits a broad specificity for the acceptor base. with a pyrimidine base as the acceptor a -oh or -sh group adjacent to the n-1 atom is essential. a substituent on position 6 hinders the reaction. on positions 4 and 5 various substituent were found to inf ... | 1979 | 486487 |
| nucleoside deoxyribosyltransferase from lactobacillus helveticus. | | 1978 | 692395 |
| deoxyribosyl transfer catalysis with trans-n-deoxyribosylase. kinetic study of purine(pyrimidine) to pyrimidine(purine) trans-n-deoxyribosylase. | kinetic studies were carried out in order to investigate the enzymic mechanism of a 215-fold-purified purine(pyrimidine) nucleoside: purine(pyrimidine) deoxyribosyl transferase fraction from lactobacillus helveticus. a variety of natural deoxyribonucleosides and bases were used as substrates. initial velocity, product inhibition and isotopic exchange studies are consistent with a ping-pong bi-bi mechanism. the kinetic parameters are used to show that this fraction is free from any contamination ... | 1976 | 1082813 |
| production and mode of action of lactocin 27: bacteriocin from a homofermentative lactobacillus. | lactobacillus helveticus strain lp27 produced a bacteriocin, lactocin 27, in dialyzable and nondialyzable forms. no evidence was obtained to indicate that lactocin 27 was under the control of extrachromosomal plasmids. lactocin 27 had a bacteriostatic effect on the indicator, lactobacillus helveticus strain ls18. it inhibited primarily protein synthesis without affecting deoxyribonucleic acid and ribonucleic acid synthesis or adenosine 5'-triphosphate levels. treatment of susceptible cells with ... | 1975 | 1137365 |
| trans-n-deoxyribosylase: purification by affinity chromatography and characterization. | trans-n-deoxyribosylase (ec 2.4.2.6) is usually considered as a single protein catalyzing indifferently the transfer of the deoxyribosyl moiety to and from a purine or a pyrimidine base. affinity chromatography of an extract from lactobacillus helveticus with two types of ligands allowed the separation and purification of two distinct trans-n-deoxyribosylases. one catalyzes specifically the deoxyribosyl transfer to and from purine bases exclusively: trans-n-deoxyribosylase-i, the other catalyzes ... | 1975 | 1175596 |
| phosphopantothenic acid--the major product of pantothenic acid accumulation and a significant growth stimulatn in lactobacillus plantarum. | non-proliferating cells of lactobacillus plantarum accumulated about 1.3 mug of pantothenic acid (pa) per milligram dry cells when placed in a phosphate-buffered solution containing glucose, nacl, and pa for 21 h. under the conditions applied for pa uptake, ph 7.5 and 38 degrees c, the accumulated pa existed almost exclusively in a bound form. free pa was observed only occasionally and then at questionably significant levels. all bound pa was released quantitatively by enzyme hydrolysis with alk ... | 1976 | 1252995 |
| isolation and characterization of is1165, an insertion sequence of leuconostoc mesenteroides subsp. cremoris and other lactic acid bacteria. | we have cloned and characterized an insertion sequence from leuconostoc mesenteroides subsp. cremoris strain db1165. this element, designated is1165, is 1553 bp, has imperfect inverted repeat ends, contains an open reading frame of 1236 bp, and is not related to any previously described insertion sequence. the copy number of is1165 varies from 4 to 13 in l. mesenteroides subsp. cremoris strains allowing genetic fingerprinting of strains based on location and number of bands on hybridization. is1 ... | 1992 | 1325060 |
| molecular cloning in lactobacillus helveticus by plasmid psa3::pva797 co-integrate formation and conjugal transfer. | a gene encoding beta-glucanase activity from bacillus amyloliquefaciens was subcloned in both orientations into plasmid shuttle vector psa3. in only one orientation could a co-integrate be generated with the conjugative plasmid pva797. the plasmid co-integrate was conjugated into lactobacillus helveticus strain cnrz450, where it was stably maintained without antibiotic selection and exhibited beta-glucanase activity. this method of introducing cloned dna into thermophilic lactobacilli will facil ... | 1991 | 1367540 |
| establishment of a host-vector system in lactobacillus helveticus with beta-galactosidase activity as a selection marker. | a host-vector system was established in lactobacillus helveticus with beta-galactosidase activity as a selection marker. plasmid pbg10 was constructed by joining the beta-galactosidase gene from l. bulgaricus, the promoter region of the erythromycin resistance gene from pam beta 1, the replication region of pbr329, and the replication region of the l. helveticus cryptic plasmid plj1. l. helveticus sbt2195 (lac- mutant), transformed with pbg10, was selected on skim milk plates. the structural gen ... | 1992 | 1368295 |
| transformation of lactobacillus helveticus subsp. jugurti with plasmid plhr by electroporation. | lactobacillus helveticus subsp. jugurti was transformed with plasmid, plhr (8.5 kilobases), by electroporation. the plasmid, plhr, consists of a cryptic plasmid, plj1, from l. helveticus subsp. jugurti, the escherichia coli vector pbr329, and the erythromycin resistance gene of pam beta 1 from enterococcus faecalis. maximum transformation efficiency of 1.3 x 10(4) transformants per microgram of dna was obtained by exposure to a pulse with an exponential decay waveform at 4 kv/cm with 25 microf c ... | 1990 | 1368569 |
| cloning and overexpression of lactobacillus helveticus d-lactate dehydrogenase gene in escherichia coli. | nad(+)-dependent d-lactate dehydrogenase from lactobacillus helveticus was purified to apparent homogeneity, and the sequence of the first 36 amino acid residues determined. using forward and reverse oligonucleotide primers, based on the n-terminal sequence and amino acid residues 220-215 of the lactobacillus bulgaricus enzyme [kochhar, s., hunziker, p. e., leong-morgenthaler, p. & hottinger, h. (1992) j. biol. chem. 267, 8499-8513], a 0.6-kbp dna fragment was amplified from l. helveticus genomi ... | 1992 | 1396685 |
| identification and characterization of helveticin v-1829, a bacteriocin produced by lactobacillus helveticus 1829. | lactobacillus helveticus 1829 produced an antimicrobial agent, designated helveticin v-1829, that demonstrated antagonistic activity against closely-related species. the agent was excreted into mrs agar, and was present in the supernatant fluids from both overnight broth and clotted milk cultures. it was heat labile (inactivated by 50 degrees c for 30 min) and was stable over the ph range 2.5 to 6.5. production of the substance was ph-dependent and maximum yields were obtained in mrs broth cultu ... | 1992 | 1429306 |
| a general method for cloning reca genes of gram-positive bacteria by polymerase chain reaction. | an internal fragment of the reca gene from eight gram-positive organisms has been amplified by using degenerate primers in a polymerase chain reaction. the internal 348- or 360-bp reca dna segments from bacillus subtilis, clostridium acetobutylicum, lactobacillus bulgaricus, lactobacillus helveticus, leuconostoc mesanteroides, listeria monocytogenes, staphylococcus aureus, and streptococcus salivarus subsp. thermophilus were amplified, cloned, and sequenced. the g + c contents of the dna from th ... | 1992 | 1629178 |
| inhibition of clostridium tyrobutyricum by bacteriocin-like substances produced by lactic acid bacteria. | lactic acid bacteria were selected for their inhibitory activity against clostridium tyrobutyricum under conditions that eliminate the effects of lactic acid and hydrogen peroxide. four strains were isolated belonging to the species lactococcus lactis ssp. lactis. the sensitivity of the inhibitory substances to pronase and trypsine indicates that they are proteins or peptides different from nisin. their resistance to phospholipase d indicates that they are also different from lactostrepcin. the ... | 1991 | 1907300 |
| single-stranded dna plasmid, vector construction and cloning of bacillus stearothermophilus alpha-amylase in lactobacillus. | vector plasmids were constructed by ligating chloramphenicol and erythromycin resistance genes to taqi-digested dna of a cryptic plasmid from lactobacillus plantarum. the minimal region of lactobacillus plasmid dna that was required for dna replication was defined and a single-stranded dna intermediate replication system was observed. homologies with other origins of replication of plasmids from gram-positive bacteria, replicating via rolling circle mechanism, were found. it was shown that the c ... | 1991 | 1961976 |
| hydrolysis of carcinogen--dna adducts by three classes of deoxyribonucleosidase to their corresponding bases. | we have investigated three different enzymes, each of which splits the glycosidic bonds of normal deoxyribonucleosides, for their ability to cleave acid-sensitive carcinogen-dna adducts: leishmania donovani purine deoxyribonucleosidase; lactobacillus helveticus trans-n-deoxyribosylase; and purine nucleoside phosphorylase. twenty-eight substrates were assayed using one or more of the enzymes, monitoring free base formation by reverse-phase hplc and a diode array detector. products were characteri ... | 1991 | 2044194 |
| galactose utilization in lactobacillus helveticus: isolation and characterization of the galactokinase (galk) and galactose-1-phosphate uridyl transferase (galt) genes. | by complementing appropriate gal lesions in escherichia coli k802, we were able to isolate the galactokinase (galk) and galactose-1-phosphate uridyl transferase (galt) genes of lactobacillus helveticus. tn10 transposon mutagenesis, together with in vivo complementation analysis and in vitro enzyme activity measurements, allowed us to map these two genes. the dna sequences of the genes and the flanking regions were determined. these revealed that the two genes are organized in the order galk-galt ... | 1991 | 2066342 |
| cloning, expression, and nucleotide sequence of the lactobacillus helveticus 481 gene encoding the bacteriocin helveticin j. | lactobacillus helveticus 481 produces a 37-kda bacteriocin called helveticin j. libraries of chromosomal dna from l. helveticus were prepared in lambda gt11 and probed for phage-producing fusion proteins that could react with polyclonal helveticin j antibody. two recombinant phage, hj1 and hj4, containing homologous inserts of 350 and 600 bp, respectively, produced proteins that reacted with antibody. these two phage clones specifically hybridized to l. helveticus 481 total genomic dna but not t ... | 1990 | 2228964 |
| conjugal transfer of plasmid pip501 from lactococcus lactis to lactobacillus delbrückii subsp. bulgaricus and lactobacillus helveticus. | plasmid pip501 was transferred by conjugation from lactococcus lactis to lactobacillus delbrückii subsp. bulgaricus and lactobacillus helveticus. only lb. delbrückii subsp. bulgaricus transconjugants could act as a donor in crosses with lc. lactis. no lactobacillus transconjugants were detected after inter- or intra-species lactobacillus crosses. plasmid pip501 has undergone no detectable deletion or rearrangement during transfer from lc. lactis to lactobacillus strains. | 1989 | 2506107 |
| complete nucleotide sequence and characterization of a cryptic plasmid from lactobacillus helveticus subsp. jugurti. | a small cryptic plasmid, plj1, was isolated from lactobacillus helveticus subsp. jugurti and was cloned into escherichia coli hb101 by using pbr329 as a vector. plasmid plj1 was 3,292 base pairs long and had single restriction endonuclease sites for pvuii, kpni, avaii, acci, hindiii, and ecori. in a maxicell system, plj1 produced a protein of about 41 kilodaltons. | 1989 | 2764571 |
| evidence for the conjugal transfer of the broad host range plasmid pip501 into strains of lactobacillus helveticus. | the conjugative broad host range plasmid pip501 was transferred from streptococcus faecalis to a series of strains of lactic streptococci used commercially as dairy starter cultures. with these transconjugants as donors the plasmid was exconjugated to two strains of lactobacillus helveticus and a commercially used strain of strep. thermophilus. there was evidence that the plasmid could transfer between isogenic derivatives of one of the strains of lact. helveticus. transfer from lact. helveticus ... | 1988 | 3146566 |
| synthesis of 2',3'-dideoxynucleosides by enzymatic trans-glycosylation. | recently, several pyrimidine and purine 2',3'-dideoxynucleosides have been shown to inhibit the replication of the human immunodeficiency virus-1 (hiv), the causative agent of the acquired immune deficiency syndrome (aids). these compounds are usually prepared by reduction of the corresponding 2'-deoxynucleosides. the present experiments demonstrate that 2',3'-dideoxynucleosides can also be made by enzymatic trans-glycosylation, using the trans-n-deoxyribosylase from lactobacillus helveticus. th ... | 1988 | 3262341 |
| characterization and purification of helveticin j and evidence for a chromosomally determined bacteriocin produced by lactobacillus helveticus 481. | lactobacillus helveticus 481 produced an antimicrobial agent active against five closely related species. the sensitive indicators included l. helveticus 1846 and 1244, l. bulgaricus 1373 and 1489, and l. lactis 970. the antimicrobial compound was active at neutral ph under aerobic or anaerobic conditions, was sensitive to proteolytic enzymes and heat (30 min at 100 degrees c), and demonstrated a bactericidal mode of action against sensitive indicators. these data confirmed that antimicrobial ac ... | 1986 | 3525512 |
| fast and slow milk-coagulating variants of lactobacillus helveticus hlm 1. | slow milk-coagulating variants were isolated from lactobacillus helveticus hlm 1, a fast strain which coagulates milk in 16 h at 42 degrees c. variants were isolated after subculturing in reconstituted skim milk or complex broth media. analysis of plasmid content revealed that in slow variants a 3.5-megadalton plasmid was missing. | 1986 | 3779528 |
| cloning and expression of the escherichia coli d-xylose isomerase gene in bacillus subtilis. | a dna fragment containing the escherichia coli d-xylose isomerase gene and d-xylulokinase gene had been isolated from an e. coli genomic bank constructed by clarke and carbon. the d-xylose isomerase gene coding for the synthesis of an important industrial enzyme, xylose isomerase, was subcloned into a bacillus-e. coli bifunctional plasmid. it was found that the intact e. coli gene was not expressed in b. subtilis, a host traditionally used to produce industrial enzymes. an attempt was then made ... | 1985 | 3919721 |
| nucleic acids of species of lactobacillus. | nucleic acid composition of 17 cultures representing the type or neotype strains of 15 named lactobacillus species was studied. nucleic acid characterization of these isolates was accompanied by a comparative study of conventional phenotypic reactions. the overall guanine plus cytosine mean deoxyribonucleic acid base composition ranged from 33 to 50% and genome sizes varied between 700 and 1500 x 10(6) daltons. sporolactobacillus inulinus contained 2500 x 10(6) daltons of chromosomal deoxyribonu ... | 1985 | 3939582 |
| [intestinal infections, contamination of the hands with the intestinal bacillus (e. coli) and the status of the microflora of the large intestine in children infested with and free of pinworms]. | | 1974 | 4608112 |
| trans-n-deoxyribosylase from lactobacillus helveticus. crystallization and properties. | | 1971 | 5156378 |
| serological properties of the wall and membrane teichoic acids from lactobacillus helveticus ncib 8025. | | 1970 | 5515109 |
| dna restriction endonuclease cleavage patterns, dna sequence similarity and phenotypical characteristics in some strains of lactobacillus helveticus and lactobacillus jugurti. | physiological characteristics, deoxyribonucleic acid (dna) base composition (% guanine + cytosine; + gc), dna sequence similarity (% dna-dna hybridization) and dna restriction endonuclease cleavage patterns of two strains of lactobacillus helveticus and four strains of lactobacillus jugurti were examined. all the strains investigated were closely related genetically, having dna-dna hybridization values ranging from 89-100%. nevertheless, these strains can be differentiated from one another on th ... | 1983 | 6311095 |
| detection and activity of lactacin b, a bacteriocin produced by lactobacillus acidophilus. | a total of 52 strains of lactobacillus acidophilus were examined for production of bacteriocins. a majority (63%) demonstrated inhibitory activity against all members of a four-species grouping of lactobacillus leichmannii, lactobacillus bulgaricus, lactobacillus helveticus, and lactobacillus lactis. four l. acidophilus strains with this activity also inhibited streptococcus faecalis and lactobacillus fermentum, suggesting a second system of antagonism. under conditions eliminating the effects o ... | 1983 | 6410990 |
| isolation and properties of beta-galactosidase of a strain of lactobacillus helveticus isolated from natural whey starter. | beta-galactosidase has been isolated from lactobacillus helveticus of a strain isolated from natural starters for the manufacture of argentine hard cheeses and its properties have been studied. the enzyme was purified 14-fold (by chromatography on deae-cellulose and sepharose 6b-deae-cellulose columns and by affinity chromatography in agarose-p-aminophenyl-beta-d-thiogalactoside). the purified extract exhibited a single band following polyacrylamide gel electrophoresis. maximum enzymatic activit ... | 1983 | 6434507 |
| plasmids and antibiotic resistances in lactobacillus helveticus and lactobacillus bulgaricus isolated from natural whey culture. | | 1983 | 6688117 |
| [peptide hydrolases of lactobacilli of the thermobacterium group. i. demonstration of these activities in lactobacillus helveticus, l. acidophilus, l. lactis and l. bulgaricus]. | the intracellular peptide hydrolase activities of lactobacillus helveticus, l. acidophilus, l. lactis, and l. bulgaricus were determined using various aminopeptidase, dipeptidase, and carboxypeptidase substrates in addition to casein and whey protein fractions. the different activities were then separated using disc gel electrophoresis. each bacterium had aminopeptidase activity towards various amino acid beta-naphthylamides and dipeptides. the four species also showed bands of true dipeptidase ... | 1982 | 6817904 |
| effect of the addition of extracts of thermophilic lactobacilli on acid production by streptococcus thermophilus in milk. | soluble extracts of 20 strains of thermophilic lactobacilli (lactobacillus helveticus, l. lactis and l. bulgaricus) were prepared and added to milk for the culture of 10 strains of streptococcus thermophilus. acid production was stimulated in 64.5% of cases for 9 of these 10 strains. the l. helveticus extracts were the most stimulatory, but the same extracts did not always strongly stimulate each strain of str. thermophilus. the stimulatory effects observed varied with the volume of extract and ... | 1981 | 6894934 |
| [clinical and bacteriological aspects of purulent pericarditis (author's transl)]. | the clinical and bacteriological characteristics of eight cases with purulent pericarditis observed over the last five years are studied. the route of the infection and dissemination in the majority of the cases (75 percent) was through pleuropulmonary lesions in the form of pneumonia and/or empyema, attributing the remaining cases to a subhepatic abscess and a pericardial infection after a thoracic surgical operation. in seven patients the diagnosis of the disease was established while they wer ... | 1980 | 7366284 |
| effect of a fermented infant formula containing viable bifidobacteria on the fecal flora composition and ph of healthy full-term infants. | we assessed the growth, tolerance, and acceptability as well as fecal flora composition and stool ph of 20 healthy full-term infants fed with a fermented whey-adapted infant formula containing viable bifidobacteria (10(6)/g of powder) during the first 2 months of life. this fermented infant formula, first biologically acidified by streptococcus thermophilus and lactobacillus helveticus, was compared to a whey-adapted, nonacidified, low-phosphate infant formula in a double-blind, randomized contr ... | 1995 | 7472904 |
| sequence analysis, distribution and expression of an aminopeptidase n-encoding gene from lactobacillus helveticus cnrz32 [gene 155 (1995) 89-93]. | lactobacillus (lb.) helveticus cnrz32 possesses a 97-kda metalloenzyme with aminopeptidase activity (pepn; ec 3.4.11.2). a 3.8-kb fragment encoding pepn was cloned into pil253 and designated psuw34. transformation of lactococcus (lc.) lactis lm0230 with psuw34 resulted in > 180-fold increase in general aminopeptidase (ap) activity using l-lysine-p-nitroanilide. southern hybridization was conducted to determine the distribution of homology to the cnrz32 pepn gene among lactic-acid bacteria (lab). ... | 1995 | 7590315 |
| characterization and distribution of two insertion sequences, is1191 and iso-is981, in streptococcus thermophilus: does intergeneric transfer of insertion sequences occur in lactic acid bacteria co-cultures? | a chromosomal repeated sequence from streptococcus thermophilus was identified as a new insertion sequence (is), is1191. this is the first is element characterized in this species. this 1313 bp element has 28 bp imperfect terminal inverted repeats and is flanked by short direct repeats of 8 bp. the single large open reading frame of is1191 encodes a 391-amino-acid protein which displays homologies with transposases encodes by is1201 from lactobacillus helveticus (44.5% amino-acid sequence identi ... | 1995 | 7651138 |
| sequence analysis, distribution and expression of an aminopeptidase n-encoding gene from lactobacillus helveticus cnrz32. | lactobacillus (lb.) helveticus cnrz32 possesses a 97-kda metalloenzyme with aminopeptidase activity (pepn; ec 3.4.11.2). a 3.8-kb fragment encoding pepn was cloned into pil253 and designated psuw34. transformation of lactococcus (lc.) lactis lm0230 with psuw34 resulted in > 180-fold increase in general aminopeptidase (ap) activity using l-lysine-p-nitroanilide. southern hybridization was conducted to determine the distribution of homology to the cnrz32 pepn gene among lactic-acid bacteria (lab). ... | 1995 | 7698673 |
| molecular cloning and dna sequence analysis of pepl, a leucyl aminopeptidase gene from lactobacillus delbrueckii subsp. lactis dsm7290. | a genomic library of lactobacillus delbrueckii subsp. lactis dsm7290 dna fragments from a sau3a partial digestion in the low-copy-number vector plg339, was used to screen escherichia coli for the presence of peptidases. using the chromogenic substrate leucine-beta-naphthylamide (leu-nh-nap) and e. coli strain cm89 lacking the corresponding enzyme activity in an enzymic plate assay, allowed the isolation of two peptidase genes; the newly described pepl and the recently cloned and sequenced pepn. ... | 1995 | 7737150 |
| partial characterization of an rpod-like gene of lactococcus lactis subsp. lactis ml3 with a polymerase chain reaction-based approach. | with degenerated oligonucleotide primers for conserved regions of bacterial sigma factor proteins, a 117-bp internal dna fragment of an rpod-like gene of lactococcus lactis subsp. lactis ml3 was amplified by the polymerase chain reaction (pcr). the dna sequence of this pcr product was determined by cycle sequencing, and the deduced amino acid sequence of this internal fragment showed an extensive homology with the known sigma factor sequences from six other microorganisms and present a 13-amino ... | 1993 | 7764136 |
| mapping of three plasmids from lactobacillus helveticus atcc 15009. | three plasmids isolated from lactobacillus helveticus atcc 15009 were analysed by restriction digestion. a restriction map of the 22.0, 6.0 and 3.5 kb plasmids is presented. the existence of genetic markers such as carbohydrate fermentation, lactose metabolism, antibiotics and heavy metal ions resistance was also investigated but the plasmids remain cryptic. | 1993 | 7764382 |
| cloning, characterization and insertional inactivation of the lactobacillus helveticus d(-) lactate dehydrogenase gene. | a plasmid, designated psuw100, encoding the d(-)lactate dehydrogenase [d(-)-ldh; nad+ oxidoreductase, ec 1.1.1.28] from lactobacillus helveticus cnrz32 was identified from a genomic library by complementation of escherichia coli fmj39. the d(-)ldh gene was localized by tn5 mutagenesis and subcloning to a 1.4-kb region of psuw100. a 2-kb drai fragment of psuw100 encoding d(-)ldh activity was subcloned and its nucleotide sequence determined. analysis of this sequence identified a putative 1,014-bp ... | 1994 | 7765104 |
| purification and characterization of angiotensin i-converting enzyme inhibitors from sour milk. | the inhibitory activity of angiotensin i-converting enzyme in milk increased during fermentation with the calpis sour milk starter containing lactobacillus helveticus and saccharomyces cerevisiae. two kinds of peptides inhibitory to angiotensin i-converting enzyme were purified from the sour milk by using four-step hplc. the amino acid sequences of these inhibitors were identified as val-pro-pro and ile-pro-pro. the concentrations of peptides providing 50% inhibition of angiotensin i-converting ... | 1995 | 7790570 |
| antimutagenicity of fermented milk. | reconstituted nonfat dry milk was fermented by lactobacillus helveticus ch65, lactobacillus acidophilus bg2fo4, streptococcus salivarius ssp. thermophilus ch3, lactobacillus delbrueckii ssp. bulgaricus 191r, and by a mixture of the latter two organisms. the fermented milks were then freeze-dried, extracted in acetone, dissolved in dimethylsulfoxide, and assayed for antimutagenicity in the ames test (salmonella typhimurium ta 100) against n-methyl, n'-nitro, n-nitroso-guanidine, and 3,2'-dimethyl ... | 1994 | 7814704 |
| isl2, a new mobile genetic element in lactobacillus helveticus. | spontaneous, phenotypically stable mutations at the beta-galactosidase locus (lacl-lacm) in lactobacillus helveticus were identified and analyzed. we found that a significant number of mutations were caused by integration of a new is element, isl2, into these lac genes. isl2 is 858 bp long, flanked by 16-bp perfect inverted repeats and generates 3-bp target duplications upon insertion. it contains one open reading frame, which shows significant homology (40.1% identity) to the putative transposa ... | 1994 | 7816043 |
| transformation of microorganisms with the plasmid vector with the replicon from pac1 from acetobacter pasteurianus. | a number of gram-negative and gram-positive bacteria species was screened for the expression of the gram-negative plasmid pack5 and pact72 with replicon of pac1 plasmid from acetobacter pasteurianus. as was described previously, both plasmids were expressed in escherichia coli, acetobacter pasteurianus, acetobacter aceti, shigella spp. and citrobacter spp. expressions of plasmids were successful in twelve species tested, comamonas terrigena, salmonella typhimurium, serratia marcescens, bacillus ... | 1995 | 7832808 |
| cryptic plasmids from lactobacillus helveticus and their evolutionary relationship. | three different cryptic plasmids from lactobacillus helveticus have been identified and their dna sequences determined. analysis and comparisons of their primary structures revealed stretches of dna with considerable homology. thus, large portions of the plasmid non-coding sequences were conserved at 80-90% identity between the different plasmids identified so far in l. helveticus. nevertheless, different plasmids found in a same host strain utilise different genes of replication, probably acqui ... | 1994 | 7851737 |
| characterization and expression of the pepn gene encoding a general aminopeptidase from lactobacillus helveticus. | an aminopeptidase n (pepn) gene was detected by dna hybridization from an industrially important lactobacillus helveticus strain using part of the l. helveticus cnrz32 pepn gene as the probe. one of five hybridization positive clones was characterized in more detail. a subcloned 3.7 kb fragment, positive in hybridization and encoding aminopeptidase activity, was sequenced and analyzed. only one open reading frame (orf) of 2532 base pairs with a coding capacity for a 95.9 kda protein could be fou ... | 1994 | 7851738 |
| use of ht-29, a cultured human colon cancer cell line, to study the effect of fermented milks on colon cancer cell growth and differentiation. | epidemiological and in vivo and in vitro experimental studies have suggested that fermented milks may interfere with the emergence and/or the development of colon cancer. the results, however, remain inconclusive. this prompted us to develop a new approach based on the use of ht-29, a cultured human colon cancer cell line, to study at the cellular level the effect of fermented milks on colon cancer cell growth and differentiation characteristics. undifferentiated ht-29 cells have been grown in t ... | 1995 | 7859355 |
| characterization and expression of the lactobacillus helveticus pepc gene encoding a general aminopeptidase. | an aminopeptidase c gene (pepc) was detected by nucleic acid hybridization from an industrially important lactobacillus helveticus strain. three hybridization positive clones were isolated from a gene library of this l. helveticus strain, and one of them was characterized in more detail. deletion mapping localized the hybridization positivity into a 2.8-kb fragment, which also encoded aminopeptidase activity. this fragment was sequenced and two open reading frames (orf1 and 2) of 1347 and 840 ba ... | 1994 | 7925424 |
| nucleotide sequence and distribution of the peppn gene from lactobacillus helveticus cnrz32. | the lactobacillus helveticus cnrz32 gene encoding a di-/tri- pepidase with prolinase activity (peppn) was sequenced. an open reading frame of 912 base pairs was identified corresponding to a peptide with a molecular mass of 35.04 kda. southern hybridization indicated that the gene sequence is well conserved in strains of lactobacilli and pediococci. | 1994 | 8039668 |
| eikenella corrodens endocarditis in an intravenous drug user: case report and literature review. | a rare case of eikenella corrodens endocarditis in an intravenous drug user is reported. repeated blood cultures from the patient established the diagnosis of this infection. however, evaluation of the cardiac function using two-dimensional echocardiography with doppler flow demonstrated a large pedunculated tricuspid vegetation. also evident on this study was a dilated right ventricle with diminished contractility and regurgitation. complete sterilization of the blood was achieved after a 2-wee ... | 1994 | 8040909 |
| characterization of is1201, an insertion sequence isolated from lactobacillus helveticus. | is1201, a 1387-bp insertion sequence isolated from lactobacillus helveticus, was identified by its nucleotide (nt) sequence. it carries a single open reading frame encoding a 369-amino-acid protein, which shares homology with transposases found in a class of related is, including isrm3 from rhizobium meliloti, is256 from staphylococcus aureus, is6120 from mycobacterium smegmatis, is1081 from m. bovis, ist2 from thiobacillus ferroxidans and is406 from pseudomonas cepacia. is1201 has terminal inve ... | 1994 | 8045427 |
| structural study on an exocellular polysaccharide produced by lactobacillus helveticus ty1-2. | lactobacillus helveticus ty1-2 produced an exocellular polysaccharide when it was cultured in reconstituted skim milk. this polysaccharide is a high molecular weight heteropolymer of d-glucopyranosyl, d-galactopyranosyl, and 2-acetamido-2-deoxy-d-glucopyranosyl residues in the molar ratio 3.0:2.8:0.9. the primary structure of the polysaccharide was shown by glycose analysis, methylation analysis, smith degradation, and nmr spectroscopy to be composed of branched heptasaccharide repeating units h ... | 1994 | 8087810 |
| gene replacement in lactobacillus helveticus. | an efficient method for gene replacement in lactobacillus helveticus cnrz32 was developed by utilizing psa3 as an integration vector. this plasmid is stably maintained in cnrz32 at 37 degrees c but is unstable at 45 degrees c. this method consisted of a two-step gene-targeting technique: (i) chromosomal integration of a plasmid carrying an internal deletion in the gene of interest via homologous recombination and (ii) excision of the vector and the wild-type gene via homologous recombination, re ... | 1993 | 8104928 |
| purification and specificity of a cell-wall-associated proteinase from lactobacillus helveticus cp790. | a cell-wall-associated proteinase from lactobacillus helveticus cp790, grown in skim milk, was purified to homogeneity by deae ion exchange chromatography in the presence of edta. its molecular weight was estimated to be 45,000 by sds-page and also by the recovery of proteinase activity only from this fraction of sds-page gel slices of crude extract. it had maximum activity at ph 6.5 and 42 degrees c. since the activity was completely inhibited by phenylmethanesulfonyl fluoride (pmsf), it was su ... | 1993 | 8113230 |
| characterization of the lactobacillus helveticus cnrz32 pepc gene. | sequence analysis of the aminopeptidase c gene (pepc) from lactobacillus helveticus cnrz32 identified a 1,332-nucleotide open reading frame coding for a polypeptide with motifs characteristic of cysteine proteinases. homology to the pepc gene appears to be widely distributed among lactic acid bacteria. | 1994 | 8117086 |
| kinetic studies of the action of lactacin f, a bacteriocin produced by lactobacillus johnsonii that forms poration complexes in the cytoplasmic membrane. | the bacteriocin lactacin f is bactericidal against lactobacillus delbrueckii, lactobacillus helveticus, and enterococcus faecalis. activity against l. delbrueckii was recently shown to be dependent on two peptides, lafa and lafx, which are encoded within the lactacin f operon (t. r. klaenhammer, fems microbiol. rev. 12:39-87, 1993). it has been proposed that two peptides form an active lactacin f complex. in this study, the action of lactacin f against e. faecalis atcc 19443 and the effects of v ... | 1994 | 8161167 |
| antihypertensive effect of the peptides derived from casein by an extracellular proteinase from lactobacillus helveticus cp790. | peptides derived from alpha s1- and beta-caseins by the lactobacillus helveticus cp790 proteinase were investigated for their inhibitory activities against angiotensin i-converting enzyme. the antihypertensive effect of casein hydrolysates in strain shr spontaneously hypertensive rats was also investigated. both alpha s1- and beta-casein hydrolysates inhibited this enzyme. some of these peptides showed enzyme inhibitory activity, and one of them from beta-casein inhibited the enzyme greatly; the ... | 1994 | 8201050 |
| two cell-wall-associated aminopeptidases from lactobacillus helveticus and the purification and characterization of apii from strain itgl1. | lactobacillus helveticus itgl1 is able to hydrolyse many amino-acyl and dipeptidyl-p-nitroanilides. analysis of heat inactivation kinetics, metal ion and protease inhibitor effects, and the subcellular location of aminopeptidase activities in both the parental strain and mutants deficient in lysyl-p-nitroanilide hydrolysis, led to the characterization of two cell-wall-associated aminopeptidases, apii and apiv. apii, which catalysed l-lysine p-nitroanilide hydrolysis, was purified about 28-fold t ... | 1993 | 8371107 |
| antimicrobial compounds from lactobacillus casei and lactobacillus helveticus. | three strains of lactobacillus casei and one of lactobacillus helveticus were examined for antagonistic activity toward twenty five indicator strains of different species. under conditions eliminating the effects of organic acid and hydrogen peroxide, culture supernatants of all the lactobacillus strains exhibited a wide spectrum of inhibitory activity toward microorganisms of different genera. the inhibitory compound secreted by one strain of l. casei was active against clostridium tyrobutyricu ... | 1993 | 8510571 |
| genetic and biochemical characterization of the lactobacillus delbrueckii subsp. lactis bacteriophage ll-h lysin. | ll-h, a virulent phage of lactobacillus delbrueckii subsp. lactis, produces a peptidoglycan-degrading enzyme, mur, that is effective on l. delbrueckii, lactobacillus acidophilus, lactobacillus helveticus, and pediococcus damnosus cell walls. in this study, the ll-h gene mur was cloned into escherichia coli, its nucleotide sequence was determined, and the enzyme produced in e. coli was purified and biochemically characterized. mur was purified 112-fold by means of ammonium sulfate precipitation a ... | 1995 | 8526515 |
| structure of an exocellular polysaccharide of lactobacillus helveticus tn-4, a spontaneous mutant strain of lactobacillus helveticus ty1-2. | lactobacillus helveticus strain tn-4, a spontaneous mutant strain of lactobacillus helveticus ty1-2, produced an exocellular polysaccharide from reconstituted skim milk. on the basis of the results of methylation analysis, enzymatic digestion, mild smith degradation, mild acid hydrolysis, acetolysis, and 1d and 2d 1h-nmr spectroscopy, it was concluded that the polysaccharide has a d-galactofuranose containing hexasaccharide repeating unit with the following structure: [formula see text] | 1995 | 8529226 |
| the structure of the exopolysaccharide produced by lactobacillus helveticus 766. | the exopolysaccharide produced by lactobacillus helveticus 766 in skimmed milk was found to be composed of d-glucose and d-galactose in a molar ratio of 2:1. linkage analysis and 1d/2d nmr studies (1h and 13c) performed on the native polysaccharide, and on oligosaccharides obtained from a partial acid hydrolysate, showed the polysaccharide to consist of hexasaccharide repeating units with the following structure: [formula: see text] | 1995 | 8536251 |
| sequencing, distribution, and inactivation of the dipeptidase a gene (pepda) from lactobacillus helveticus cnrz32. | previously, the gene for a general dipeptidase (pepda) was isolated from a gene bank of lactobacillus helveticus cnrz32. the pepda gene consists of a 1,422-bp open reading frame which could encode a polypeptide of 53.5 kda. no significant identity was found between the deduced amino acid sequence of the pepda product and the sequence for other polypeptides reported in genbank. southern hybridization studies with a pepda probe indicated that the nucleotide sequence for pepda is not well conserved ... | 1996 | 8550503 |
| an x-prolyl dipeptidyl aminopeptidase (pepx) gene from lactobacillus helveticus. | the x-prolyl dipeptidyl aminopeptidase gene (pepx) of an industrially used lactobacillus helveticus strain has been detected by nucleic acid hybridization, cloned, characterized and sequenced. one orf of 2379 bp with coding capacity for a 90.6 kda protein (pepx) was found. the orf was preceded by a typical prokaryotic promoter region. an inverted repeat structure with delta g of -84.1 kj mol-1 was found downstream of the coding region. the deduced amino acid sequence of the 90.6 kda protein show ... | 1995 | 8574400 |
| modulation of proliferation, second messenger levels, and morphotype expression of the rat intestinal epithelial cell line iec-6 by fermented milk. | trophic effects of milk fermented with lactobacillus helveticus, lactobacillus paracasei ssp. paracasei, bifidobacterium sp., or the combination of lactobacillus bulgaricus and streptococcus thermophilus (yogurt) were studied on the iec-6 intestinal epithelial cell line. incorporation of [methyl-3h]thymidine, mitochondrial dehydrogenase activities, cyclic amp production, and differentiation of levels of the iec-6 strain were evaluated between the 15th and 30th passage in culture. all fermented a ... | 1996 | 8675780 |
| molecular characterization, over-expression and purification of a novel dipeptidase from lactobacillus helveticus. | a dipeptidase gene (pepd) from an industrial lactobacillus helveticus strain was isolated by colony hybridization. an open reading frame (orf) of 1422 base pairs (bp) with a coding capacity for a 53.5-kda protein (pepd) was identified. the orf was preceded by a typical prokaryotic promoter region, and an inverted repeat structure with delta g of -51.0 kj mol-1 was found downstream of the coding region. the deduced amino acid sequence of the 53.5-kda protein revealed no marked homologies when com ... | 1996 | 8766699 |
| the effect of milk fermentation by lactobacillus helveticus on the release of peptides during in vitro digestion. | this study evaluated the effect of protein hydrolysis by lactic acid bacteria during milk fermentation on the release of amino acids and peptides duing subsequently simulated peptic and pancreatic digestion. after digestion with trypsin, we compared the elution patterns of proteins and peptides obtained from unfermented milk and from milk fermented by lactobacillus helveticus under ph control, using hplc gel filtration and reverse-phase hplc. the results indicate that milk fermentation affects t ... | 1996 | 8827460 |
| characterization of a proteinaceous antimicrobial produced by lactobacillus helveticus cnrz450. | an antimicrobial substance which resembles a bacteriocin was identified in culture supernatant fluids of lactobacillus helveticus strain cnrz450. the bacteriocin was active against a narrow range of strains from closely related species of homofermentative lactobacilli. its mode of action appeared to be bacteriostatic. partial purification of the bacteriocin suggested that it was a complex protein with a mol. wt of between 30 and 50 kda, although there is some evidence that the polypeptide monome ... | 1996 | 8852681 |
| structural elucidation of an extracellular polysaccharide produced by lactobacillus helveticus. | an extracellular polysaccharide produced by a strain of lactobacillus helveticus isolated from cheese milk has been investigated. sugar and methylation analysis together with 1h and 13c nmr spectroscopy revealed that the polysaccharide is composed of hexasaccharide repeating units. the sequence of sugar residues was determined by use of two-dimensional nuclear overhauser effect spectroscopy and heteronuclear multiple-bond correlation experiments. the structure of the repeating unit of the exopol ... | 1996 | 8864228 |
| dna sequence analysis, expression, distribution, and physiological role of the xaa-prolyldipeptidyl aminopeptidase gene from lactobacillus helveticus cnrz32. | lactobacillus helveticus cnrz32 possesses an xaa-prolyldipeptidyl aminopeptidase (pepx), which releases amino-terminal dipeptides from peptides containing proline residues in the penultimate position. the pepx gene, designated pepx, from lb. helveticus cnrz32 was sequenced. analysis of the sequence identified a putative 2379-bp pepx open-reading frame, which encodes a polypeptide of 793 amino acid residues with a deduced molecular mass of 88,111 da. the gene shows significant sequence identity w ... | 1996 | 8867635 |
| identification of an antihypertensive peptide from casein hydrolysate produced by a proteinase from lactobacillus helveticus cp790. | casein hydrolysate, produced by an extracellular proteinase from lactobacillus helveticus cp790, was fractionated by two-step reverse-phase hplc. only one fraction showed antihypertensive activity as measured by systolic blood pressure in spontaneously hypertensive rats after oral administration. ten peptides in the fraction were further purified and identified by analysis of amino acid sequences. each identified peptide was chemically synthesized, and the antihypertensive activity of each pepti ... | 1996 | 8880454 |
| decrease of tissue angiotensin i-converting enzyme activity upon feeding sour milk in spontaneously hypertensive rats. | blood pressure increases were inhibited by feeding a diet containing sour milk fermented by a starter containing lactobacillus helveticus and saccharomyces cerevisiae to spontaneously hypertensive rats. in rats fed with the sour milk, the angiotensin i-converting enzyme activity of the aorta was significantly lower than that of rats fed with the control commercial diet. | 1996 | 8901109 |
| 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 |
| a new, broad-substrate-specificity aminopeptidase from the dairy organism lactobacillus helveticus sbt 2171. | an aminopeptidase with a very broad substrate specificity was purified to homogeneity from lactobacillus helveticus sbt 2171 by fplc. the enzyme was purified 144-fold from a cell-free extract with a yield of 16%. the purified enzyme appeared as a single band on an sds-page gel. it had a molecular mass of 95 kda and an isoelectric point of 4.9. the enzyme hydrolysed a large range of naphthylamide- and nitroanilide-substituted amino acids, as well as several di-, tri- and oligopeptides. it also ex ... | 1996 | 8936307 |
| 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 |
| sequence and analysis of the replication region of the staphylococcus xylosus plasmid psx267. | the region of the 29.5-kb plasmid psx267 from staphylococcus xylosus dsm 20267 that is required for autonomous replication in staphylococci was isolated on a 1.8-kb dna fragment. the sequence analysis of the fragment yielded two open reading frames, repa and orf2, encoding proteins of 37.2 and 13.2 kda, respectively. the deduced amino acid sequence of repa showed similarity to the replication initiator protein of plasmid pad1 from enterococcus faecalis, to two proteins of unknown function encode ... | 1996 | 8982076 |
| isolation and characterization of a plasmid from lactobacillus helveticus cp53. | a plasmid, pcp53 (11.5 kilo base pairs long), was isolated from lactobacillus helveticus cp53 and its restriction map was constructed. a chimeric plasmid, pcp53d (4.7 kb), which had a 2.0-kb hindiii fragment from pcp53 and a tetracycline resistance (tc) gene from streptococcus faecalis replicated and expressed tetracycline resistance in lactobacillus casei cp680. fifteen strains of l. helveticus were transformed with pcp53d by electroporation and selected for tc resistance. transformants were ob ... | 1996 | 8988641 |
| 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 |
| 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 |
| lactobacillus helveticus: strain typing and genome size estimation by pulsed field gel electrophoresis. | genomic dnas of 22 strains of lactobacillus helveticus of various geographical origins were analyzed by pulsed-field gel electrophoresis. two endonucleases, smai and sgrai, of the 19 tested produced dna fragments useful for strain comparison. with the endonuclease smai, a characteristic restriction pattern was identified for 18 of the 22 strains. the percentage of similarity (dice coefficient) between the profiles varied between 26% and 100%, and clustering was accomplished by using the unweight ... | 1997 | 9009072 |
| 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 |
| [the antagonistic properties of bacteria isolated from the digestive tract of female mink housed in the area of the chernobyl atomic electric power station]. | differences in species composition, number and level of antagonistic activity of bacteria isolated from the digestive tract of chernobyl female minks of various age and with different immunological state have been established. prevalence of anaerobes (bifidobacteria) and microaerophils (lactic acid bacteria) with the increase of microorganisms concentration along the channel: stomach, small and large intestine (10(7)-10(10)/g) was found in all the departments of digestive tract of minks. among t ... | 1996 | 9064070 |
| identification and characterization of is1381, a new insertion sequence in streptococcus pneumoniae. | a new insertion sequence (is1381) was identified in the genome of streptococcus pneumoniae r6 as an 846-bp segment containing 20-bp terminal inverted repeats and flanked by 7-bp direct repeats. the three sequenced copies of this element have two overlapping open reading frame (orf) genes named orfa and orfb. however, significant variations between individual copies were found, suggesting that inactivating mutations have occurred in an original single orf. accordingly, the consensus is1381 elemen ... | 1997 | 9079939 |
| development of oligonucleotide primers from the 16s-23s rrna intergenic sequences for identifying different dairy and probiotic lactic acid bacteria by pcr. | spacer regions between the 16s and 23s rrna genes of different dairy and probiotic lactic acid bacteria were amplified by the polymerase chain reaction (pcr) with conserved primers and the nucleotide sequences of these spacer regions were determined. amplification/oligonucleotide primer pairs were designed for lactobacillus paracasei, lactobacillus rhamnosus, lactobacillus delbrueckii, lactobacillus acidophilus, lactobacillus helveticus and streptococcus thermophilus based on the differences in ... | 1997 | 9081225 |
| characterization of a thiol-dependent endopeptidase from lactobacillus helveticus cnrz32. | an endopeptidase gene (pepe) was isolated from a previously constructed genomic library of lactobacillus helveticus cnrz32. the pepe gene consisted of a 1,314-bp open reading frame encoding a putative peptide of 52.1 kda. significant identity was found between the deduced amino acid sequence of pepe and the sequences for aminopeptidase c from lactobacillus delbrueckii subsp. lactis dsm7290, l. helveticus cnrz32, streptococcus thermophilus cnrz302, and lactococcus lactis subsp. cremoris am2. a re ... | 1997 | 9098049 |
| cloning and functional expression in escherichia coli of the gene encoding the di- and tripeptide transport protein of lactobacillus helveticus. | the gene encoding the di- and tripeptide transport protein (dtpt) of lactobacillus helveticus (dtptlh) was cloned with the aid of the inverse pcr technique and used to complement the dipeptide transport-deficient and proline-auxotrophic escherichia coli e1772. functional expression of the peptide transporter was shown by the uptake of prolyl-[14c] alanine in whole cells and membrane vesicles. peptide transport via dtpt in membrane vesicles is driven by the proton motive force. the system has spe ... | 1997 | 9172341 |
| 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 |
| identification of a cold shock gene in lactic acid bacteria and the effect of cold shock on cryotolerance. | when lactic acid bacterial cultures were frozen at -20 degrees c for 24 h, the cell viability decreased drastically, but when they were cold shocked at 10 degrees c for 2 h prior to freezing, viability improved significantly for the lactococcus lactis subsp. lactis strains (25-37%) and pediococcus pentosaceus po2 (18%), but not for the lactococcus lactis subsp. cremoris strains tested or for one strain of lactobacillus helveticus lb1 and streptococcus thermophilus ts2. when the period for cold s ... | 1997 | 9175562 |
| 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 |
| 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 |
| 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 |