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attenuation regulation of amino acid biosynthetic operons in proteobacteria: comparative genomics analysis.candidate attenuators were identified that regulate operons responsible for biosynthesis of branched amino acids, histidine, threonine, tryptophan, and phenylalanine in gamma- and alpha-proteobacteria, and in some cases in low-gc gram-positive bacteria, thermotogales and bacteroidetes/chlorobi. this allowed us not only to describe the evolutionary dynamics of regulation by attenuation of transcription, but also to annotate a number of hypothetical genes. in particular, orthologs of ygea of esche ...200415135544
antimicrobial potential of immobilized lactococcus lactis subsp. lactis atcc 11454 against selected bacteria.immobilization of living cells of lactic acid bacteria could be an alternative or complementary method of immobilizing organic acids and bacteriocins and inhibit undesirable bacteria in foods. this study evaluated the inhibition potential of immobilized lactococcus lactis subsp. lactis atcc 11454 on selected bacteria by a modified method of the agar spot test. l. lactis was immobilized in calcium alginate (1 to 2%)-whey protein concentrate (0 and 1%) beads. the antimicrobial potential of immobil ...200415222547
high-level gene expression in lactobacillus plantarum using a pheromone-regulated bacteriocin promoter.to use promoters and regulatory genes involved in the production of the bacteriocin sakacin p to obtain high-level regulated gene expression in lactobacillus plantarum.200415242451
lipid-mediated light activation of a mechanosensitive channel of large conductance.this paper describes the reversible activation of a mechanosensitive channel via a light-sensitive lipid mimic. for these experiments, the mechanosensitive channel of large conductance (mscl) protein from lactococcus lactis and escherichia coli was reconstituted in lipid bilayers composed of 80 mol % 1,2-dioleoyl-sn-glycero-3-phosphocholine and 20 mol % di-(5-[[4-(4-butylphenyl)azo]phenoxy]pentyl)phosphate (4-azo-5p). light-induced isomerization of the azobenzene moiety of 4-azo-5p from trans to ...200415301476
ferrihydrite reduction by geobacter species is stimulated by secondary bacteria.geobacter species such as g. bremensis, g. pelophilus, and g. sulfurreducens are obligately anaerobic and grow in anoxic, non-reduced medium by fast reduction of soluble ferric citrate. in contrast, insoluble ferrihydrite was either only slowly or not reduced when supplied as electron acceptor in similar growth experiments. ferrihydrite reduction was stimulated by addition of a reducing agent or by concomitant growth of secondary bacteria that were physiologically and phylogenetically as diverse ...200415340790
using lactococcus lactis for glutathione overproduction.glutathione and gamma-glutamylcysteine were produced in lactococcus lactis using a controlled expression system and the genes gsha and gshb from escherichia coli encoding the enzymes gamma-glutamylcysteine synthetase and glutathione synthetase. high levels of gamma-glutamylcysteine were found in strains growing on chemically defined medium and expressing either gsha alone or both gsha and gshb. as anticipated, glutathione was found in a strain expressing gsha and gshb. the level of glutathione p ...200515490155
effect of sorghum vulgare phosphoenolpyruvate carboxylase and lactococcus lactis pyruvate carboxylase coexpression on succinate production in mutant strains of escherichia coli.sorghum vulgare phosphoenolpyruvate carboxylase (pepc) and lactococcus lactis pyruvate carboxylase (pyc) were overexpressed in escherichia coli concurrently to improve the production of succinate, a valuable industrial specialty chemical. this coexpression system was also applied to e. coli mutant strains strategically designed by inactivating the competing pathways of succinate formation. the highest level of succinate production was observed in e. coli strains coexpressing both pepc and pyc wh ...200515565333
a nudix enzyme removes pyrophosphate from dihydroneopterin triphosphate in the folate synthesis pathway of bacteria and plants.removal of pyrophosphate from dihydroneopterin triphosphate (dhntp) is the second step in the pterin branch of the folate synthesis pathway. there has been controversy over whether this reaction requires a specific pyrophosphohydrolase or is a metal ion-dependent chemical process. the genome of lactococcus lactis has a multicistronic folate synthesis operon that includes an open reading frame (ylgg) specifying a putative nudix hydrolase. because many nudix enzymes are pyrophosphohydrolases, ylgg ...200415611104
function of prokaryotic and eukaryotic abc proteins in lipid transport.atp binding cassette (abc) proteins of both eukaryotic and prokaryotic origins are implicated in the transport of lipids. in humans, members of the abc protein families a, b, c, d and g are mutated in a number of lipid transport and metabolism disorders, such as tangier disease, stargardt syndrome, progressive familial intrahepatic cholestasis, pseudoxanthoma elasticum, adrenoleukodystrophy or sitosterolemia. studies employing transfection, overexpression, reconstitution, deletion and inhibition ...200415749056
combined effect of high-pressure treatments and bacteriocin-producing lactic acid bacteria on inactivation of escherichia coli o157:h7 in raw-milk cheese.the effect of high-pressure (hp) treatments combined with bacteriocins of lactic acid bacteria (lab) produced in situ on the survival of escherichia coli o157:h7 in cheese was investigated. cheeses were manufactured from raw milk inoculated with e. coli o157:h7 at approximately 10(5) cfu/ml. seven different bacteriocin-producing lab were added at approximately 10(6) cfu/ml as adjuncts to the starter. cheeses were pressurized on day 2 or 50 at 300 mpa for 10 min or 500 mpa for 5 min, at 10 degree ...200516000741
transcriptional analysis of the cyclopropane fatty acid synthase gene of lactococcus lactis mg1363 at low ph.cyclopropane fatty acid synthase (cfa) catalyses the transfer of a methyl group from s-adenosylmethionine (sam) to unsaturated fatty acids. northern blot experiments demonstrated that the lactococcus lactis mg1363 cfa gene is mainly expressed as a bicistronic transcript together with metk, the gene encoding sam synthetase, and is highly induced by acidity. the cfa promoter was characterized by 5'-race pcr, and fused to beta-galactosidase by cloning into the pak80 plasmid. this transcriptional fu ...200516098686
molecular analysis of colonized bacteria in a human newborn infant gut.the complex ecosystem of intestinal microflora is estimated to harbor approximately 400 different microbial species, mostly bacteria. however, studies on bacterial colonization have mostly been based on culturing methods, which only detect a small fraction of the whole microbiotic ecosystem of the gut. to clarify the initial acquisition and subsequent colonization of bacteria in an infant within the few days after birth, phylogenetic analysis was performed using 16s rdna sequences from the dna i ...200516145549
drug-lipid a interactions on the escherichia coli abc transporter msba.msba is an essential atp-binding cassette half-transporter in the cytoplasmic membrane of the gram-negative escherichia coli and is required for the export of lipopolysaccharides (lps) to the outer membrane, most likely by transporting the lipid a core moiety. consistent with the homology of msba to the multidrug transporter lmra in the gram-positive lactococcus lactis, our recent work in e. coli suggested that msba might interact with multiple drugs. to enable a more detailed analysis of multid ...200516159769
the mode of replication is a major factor in segregational plasmid instability in lactococcus lactis.the effects of the rolling-circle and theta modes of replication on the maintenance of recombinant plasmids in lactococcus lactis were studied. heterologous escherichia coli or bacteriophage lambda dna fragments of various sizes were inserted into vectors based on either the rolling-circle-type plasmid pwv01 or the theta-type plasmid pambeta1. all pambeta1 derivatives were stably maintained. pwv01 derivatives, however, showed size-dependent segregational instability, in particular when large dna ...199316348863
antimicrobial properties of lactic acid bacteria and yeast-lab cultures isolated from traditional fermented milk against pathogenic escherichia coli and salmonella enteritidis strains.the survival and growth of escherichia coli 3339 and salmonella enteritidis 949575 isolated from human clinical samples, in milk fermented with lactic acid bacteria (lab) and yeast strains previously isolated from zimbabwean naturally fermented milk (nfm) was studied. the lab starter cultures used were lactococcus lactis subsp. lactis biovar. diacetylactis c1 alone (c1) or in combination with candida kefyr 23 (c1/23), l. lactis subsp. lactis lc261 alone (lc261) or in combination with c. kefyr 23 ...200616387379
expression of helicobacter pylori cag12 gene in lactococcus lactis mg1363 and its oral administration to induce systemic anti-cag12 immune response in mice.to develop an oral vaccine against helicobacter pylori infection, we have expressed the h. pylori cag12 (hp0532) gene, encoding the outer membrane protein cag12 (31 kda), in a live delivery vehicle lactococcus lactis. the cag12 gene was amplified by polymerase chain reaction (pcr) using the genomic dna of h. pylori k51 isolated from korean patients. dna sequence analysis revealed that the cag12 gene of h. pylori k51 has 98.1 and 97.4% identity with individual cag12 genes of the h. pylori 26695 a ...200616586107
restriction for gene insertion within the lactococcus lactis ll.ltrb group ii intron.the ll.ltrb intron, from the low g+c gram-positive bacterium lactococcus lactis, was the first bacterial group ii intron shown to splice and mobilize in vivo. the detailed retrohoming and retrotransposition pathways of ll.ltrb were studied in both l. lactis and escherichia coli. this bacterial retroelement has many features that would make it a good gene delivery vector. here we report that the mobility efficiency of ll.ltrb expressing ltra in trans is only slightly affected by the insertion of ...200616973892
lex marks the spot: the virulent side of sos and a closer look at the lexa regulon.the sos response that responds to dna damage induces many genes that are under lexa repression. a detailed examination of lexa regulons using genome-wide techniques has recently been undertaken in both escherichia coli and bacillus subtilis. these extensive and elegant studies have now charted the extent of the lexa regulons, uncovered many new genes, and exposed a limited overlap in the lexa regulon between the two bacteria. as more bacterial genomes are analysed, more curiosities in lexa regul ...200617042786
universal method for synthesis of artificial gel antibodies by the imprinting approach combined with a unique electrophoresis technique for detection of minute structural differences of proteins, viruses, and cells (bacteria). iii: gel antibodies against cells (bacteria).artificial antibodies in the form of gel granules were synthesized from the monomers acrylamide and n,n'-methylenebisacrylamide by the imprinting method in the presence of echerichia coli bacteria as template. the electrophoretic migration velocities of the gel antibodies (i) saturated with the antigen (escherichia coli mre-600), (ii) freed of the antigen, and (iii) resaturated with bacteria, were determinated by electrophoresis in a rotating narrow-bore tube of 245 mm length and the 2.5 and 9.6 ...200617136716
human lysozyme expressed in the mammary gland of transgenic dairy goats can inhibit the growth of bacteria that cause mastitis and the cold-spoilage of milk.the addition of human milk components with intrinsic antimicrobial activity to livestock milk by genetic engineering has the potential to benefit milk safety and production as well as the health of the lactating animal. as a model for the dairy cow, we generated transgenic goats that expressed human lysozyme in their milk at 68% of the levels found in human milk. milk from these transgenic animals had a bacteriostatic effect on both in vitro and in vivo growth of several microorganisms important ...200617199520
expression, purification, and characterization of arginine deiminase from lactococcus lactis ssp. lactis atcc 7962 in escherichia coli bl21.the arca gene that encodes arginine deiminase (adi, ec 3.5.3.6)--a key enzyme of the adi pathway--was cloned from lactococcus lactis ssp. lactis atcc 7962. the deduced amino acid sequence of the arca gene showed high homology with the arca gene from lactobacillus plantarum (99%) and from lactobacillus sakei (60%), respectively. the arca gene from lc. lactis spp. lactis atcc 7962 was expressed in soluble fraction of recombinant escherichia coli bl21. adi produced from lc. lactis spp. lactis atcc ...200717223359
genotypic and phenotypic diversity of lactococcus lactis isolates from batzos, a greek pdo raw goat milk cheese.the genotypic and phenotypic variability of 40 lactococcus lactis isolates obtained from three cheese-making trials of batzos cheese made one in each, winter, spring and summer was investigated. rapd-pcr, plasmid profiling and pfge were used to study the genetic variability and distinguish closely related isolates. results showed a high degree of heterogeneity among strains. according to pfge data, all strains except one were clustered together (at a similarity level of approximately 50%) with t ...200717241681
characterization of the lactococcal group ii intron target site in its native host.the lactococcus lactis group ii intron (ll.ltrb) retrohomes into the ltrb gene at high efficiency. to date, the critical dna bases recognized in vivo by the ll.ltrb ribonucleoprotein (rnp) have been exclusively elucidated in escherichia coli. however, recent evidence indicates host-dependant differences in ll.ltrb mobility, raising the possibility of limitations of the current model for rnp-homing site recognition in the native l. lactis host. in this work, intron retargeting experiments in l. l ...200717408740
in vivo functional analyses of the type ii acyl carrier proteins of fatty acid biosynthesis.acyl carrier protein (acp) is a key component of the fatty acid synthesis pathways of both type i and type ii synthesis systems. a large number of structure-function studies of various type ii acps have been reported, but all are in vitro studies that assayed function or interaction of mutant acps with various enzymes of fatty acid synthesis or transfer. hence in these studies functional properties of various mutant acps were assayed with only a subset of the many acp-interacting proteins, which ...200717522044
improvement of a nisin-inducible expression vector for use in lactic acid bacteria.the plasmid pmsp3535 is a popular vector for nisin-inducible expression of heterologous genes in lactic acid bacteria. however, the maximum protein expression level achievable with pmsp3535 is relatively low. in an effort to increase expression we modified pmsp3535 to create a high expression variant termed pmsp3535h2. modifications included removal of a small nisa peptide fragment from the p nisa promoter and addition of a bidirectional transcription terminator. in addition the plasmid copy num ...200717624430
the unconventional xer recombination machinery of streptococci/lactococci.homologous recombination between circular sister chromosomes during dna replication in bacteria can generate chromosome dimers that must be resolved into monomers prior to cell division. in escherichia coli, dimer resolution is achieved by site-specific recombination, xer recombination, involving two paralogous tyrosine recombinases, xerc and xerd, and a 28-bp recombination site (dif) located at the junction of the two replication arms. xer recombination is tightly controlled by the septal prote ...200717630835
identification of lactic acid bacteria within the consortium of a kefir grain by sequencing 16s rdna variable regions.the microflora of a kefir grain was identified using a polymerase chain reaction-based strategy combined with 16s rrna gene sequencing. dna was extracted from the kefir grain and amplified in its 16s rdna v1 and v2 regions. to guarantee a good representation of the overall lactic acid bacteria populations, dna amplification was performed separately with primers specific either to the dominant or to the less abundant bacterial groups. the amplified fragments were cloned in escherichia coli and th ...200717760349
nisin biosynthesis in vitro.the lantibiotic nisin is produced by lactococcus lactis. in the biosynthesis of nisin, the enzyme nisb dehydrates nisin precursor, and the enzyme nisc is needed for lanthionine formation. in this study, the nisa gene encoding the nisin precursor, and the genes nisb and nisc of the lantibiotic modification machinery were expressed together in vitro by the rapid translation system (rts). analysis of the rts mixture showed that fully modified nisin precursor was formed. by treating the mixture with ...200717827976
on the energy-dependence of hoechst 33342 transport by the abc transporter lmra.lmra is an atp-binding cassette (abc) multidrug transporter from lactococcus lactis, and is a structural homologue of the human multidrug resistance p-glycoprotein (abcb1), the overexpression of which is associated with multidrug resistance in tumours. we recently observed that a truncated version of lmra lacking the nucleotide-binding domain mediates a proton motive force-dependent ethidium transport reaction by catalyzing proton-ethidium symport. this finding raised the question whether proton ...200818061142
structure of the branched-chain keto acid decarboxylase (kdca) from lactococcus lactis provides insights into the structural basis for the chemoselective and enantioselective carboligation reaction.the thiamin diphosphate (thdp) dependent branched-chain keto acid decarboxylase (kdca) from lactococcus lactis catalyzes the decarboxylation of 3-methyl-2-oxobutanoic acid to 3-methylpropanal (isobutyraldehyde) and co2. the enzyme is also able to catalyze carboligation reactions with an exceptionally broad substrate range, a feature that makes kdca a potentially valuable biocatalyst for c-c bond formation, in particular for the enzymatic synthesis of diversely substituted 2-hydroxyketones with h ...200718084069
bidirectional cell-surface anchoring function of c-terminal repeat region of peptidoglycan hydrolase of lactococcus lactis il1403.with the aim of constructing an efficient protein display system for lactic acid bacteria (labs), the effect of fusion direction on the cell-surface binding activity of the c-terminal region of the peptidoglycan hydrolase (cph) of lactococcus lactis il1403 was studied. cph fused to the alpha-amylase (amy) of streptococcus bovis 148 either at its c-terminus (cph-amy) or at its n-terminus (amy-cph) was expressed intracellularly in escherichia coli. this domain was able to direct binding of amy to ...200818343337
expression of c-terminal repeat region of peptidoglycan hydrolase of lactococcus lactis il1403 in methylotrophic yeast pichia pastoris.the c-terminal region of the peptidoglycan hydrolase (cph) of lactococcus lactis il1403 produced intracellularly in escherichia coli was able to attach to the surface of cells of lactobacillus casei nrrl b-441, bacillus subtilis 168, e. coli xl1-blue and saccharomyces cerevisiae ifo0216. therefore, this domain is a suitable fusion partner for the adhesion of proteins to cell surfaces. the production of cell-surface adhesive proteins using this domain in pichia pastoris is particularly attractive ...200818343340
expression of the capsid protein of porcine circovirus type 2 in lactococcus lactis for oral vaccination.diseases associated with porcine circovirus type 2 (pcv2) infections are becoming a major problem for the swine industry worldwide. the capsid protein (cap) of pcv2 is an antigen important for both early diagnosis and development of vaccines. in this study, lactococcus lactis was used as vehicle to deliver the pcv2 antigen in an attempt to develop oral vaccine. a cap gene with a deleted nuclear localization signal sequence (dcap) was cloned into an escherichia coli/l. lactis shuttle vector psec: ...200818406475
the lactococcus lactis fabf fatty acid synthetic enzyme can functionally replace both the fabb and fabf proteins of escherichia coli and the fabh protein of lactococcus lactis.the genome of lactococcus lactis encodes a single long chain 3-ketoacyl-acyl carrier protein synthase. this is in contrast to its close relative, enterococcus faecalis, and to escherichia coli, both of which have two such enzymes. in e. faecalis and e. coli, one of the two long chain synthases (fabo and fabb, respectively) has a role in unsaturated fatty acid synthesis that cannot be satisfied by fabf, the other long chain synthase. since l. lactis has only a single long chain 3-ketoacyl-acyl ca ...200818523755
molecular characterization of a clostridium difficile bacteriophage and its cloned biologically active endolysin.clostridium difficile infection is increasing in both frequency and severity, with the emergence of new highly virulent strains highlighting the need for more rapid and effective methods of control. here, we show that bacteriophage endolysin can be used to inhibit and kill c. difficile. the genome sequence of a novel bacteriophage that is active against c. difficile was determined, and the bacteriophage endolysin gene was subcloned and expressed in escherichia coli. the partially purified endoly ...200818708505
introduction of an nadh regeneration system into klebsiella oxytoca leads to an enhanced oxidative and reductive metabolism of glycerol.redox cofactors play crucial roles in the metabolic and regulatory network of living organisms. we reported here the effect of introducing a heterogeneous nadh regeneration system into klebsiella oxytoca on cell growth and glycerol metabolism. expression of fdh gene from candida boidinii in k. oxytoca resulted in higher intracellular concentrations of both nadh and nad(+) during the fermentation metaphase, with the ratio of nadh to nad(+) unaltered and cell growth unaffected, interestingly diffe ...200919100856
eci5, a group iib intron with high retrohoming frequency: dna target site recognition and use in gene targeting.we find that group ii intron eci5, a subclass cl/iib1 intron from an escherichia coli virulence plasmid, is highly active in retrohoming in e. coli. both full-length eci5 and an eci5-deltaorf intron with the intron-encoded protein expressed separately from the same donor plasmid retrohome into a recipient plasmid target site at substantially higher frequencies than do similarly configured lactococcus lactis ll.ltrb introns. a comprehensive view of dna target site recognition by eci5 was obtained ...200919155322
secretory expression of k88 (f4) fimbrial adhesin faeg by recombinant lactococcus lactis for oral vaccination and its protective immune response in mice.k88 (f4) fimbrial adhesin, faeg, was expressed extracellularly in lactococcus lactis using a nisin-controlled gene expression system. the antibody response and protective efficacy of the recombinant bacteria (l. lactis [spnz8048-faeg]) against live enterotoxigenic e. coli (etec) c(83549) challenge were evaluated in icr mice. mice vaccinated with l. lactis [spnz8048-faeg] had a significantly increased antigen-specific igg level in the serum and decreased mortality rate (p < 0.05) compared with th ...200919277476
large increase in brazzein expression achieved by changing the plasmid /strain combination of the nice system in lactococcus lactis.to evaluate brazzein production in lactococcus lactis using the nisin-controlled expression (nice) system. the approach is through analysis of different plasmid/strain combinations.200919413801
inhibition of uropathogens by lactic acid bacteria isolated from dairy foods and cow's intestine in western nigeria.a total of 96 lactic acid bacteria (lab) were isolated from african indigenous fermented products and cow's intestines to study their inhibitory capability against multi-drug-resistant uropathogens. escherichia coli accounted for approximately 45% of isolated uropathogens, followed by staphylococcus spp. (20%). the gram negative uropathogens were highly resistant to quinolones, co-trimoxazole, teicoplanin and some beta-lactams, while the staphylococcus spp. showed high resistance to aminoglycosi ...200919529917
possible promoter regions within the proteolytic system in streptococcus thermophilus and their interaction with the cody homolog.possible promoter regions preceding 14 genes belonging to the proteolytic system of streptococcus thermophilus klds 3.0503 were predicted by a promoter analysis software nnpp. the 14 genes included an extracellular protease gene prts, an oligopeptide abc transport system gene amia1, and 12 genes, respectively, encoding peptidases pepa, peps, pepn, pepc, pepb, pepq, pepv, pept, pepm, pepxp, pepp, and pepo. these predicted promoter sequences were cloned and inserted into the upstream of a promoter ...200919552712
intra- and interspecies conjugal transfer of tn916-like elements from lactococcus lactis in vitro and in vivo.tetracycline-resistant lactococcus lactis strains originally isolated from polish raw milk were analyzed for the ability to transfer their antibiotic resistance genes in vitro, using filter mating experiments, and in vivo, using germfree rats. four of six analyzed l. lactis isolates were able to transfer tetracycline resistance determinants in vitro to l. lactis bu2-60, at frequencies ranging from 10(-5) to 10(-7) transconjugants per recipient. three of these four strains could also transfer res ...200919666731
molecular properties of the glucosaminidase acma from lactococcus lactis mg1363: mutational and biochemical analyses.the major autolysin acma of lactococcus lactis ssp. cremoris mg1363 is a modular protein consisting of an n-terminal signal sequence, a central enzymatic region (glu(acma) as a glucosaminidase), and a c-terminal cell-recognition domain (lysm123). glu(acma) (about 160 amino acids) belongs to the glycoside hydrolase (gh) 73 family, and the two acidic residues e128 and d153 have been thought to be catalytically important. in this study, amino-acid substitution analysis of acma was first carried out ...200919686822
oral administration of lactococcus lactis expressing helicobacter pylori cag7-ct383 protein induces systemic anti-cag7 immune response in mice.to express the 3'-region (1152 bp) of the cag7 gene of helicobacter pylori 51 strain, encoding the c-terminal 383 amino acid (ct383 aa) region of cag7 protein that is known to cover the needle region of t4ss, in a live delivery vehicle lactococcus lactis, the cag7-ct383 gene was amplified by pcr. dna sequence analysis revealed that the amino acid sequence of cag7-ct383 of h. pylori 51 shared 98.4% and 97.4% identity with h. pylori 26695 and j99, respectively. intramuscular injection of the gst-c ...200919807786
expression of espa in lactococcus lactis nz9000 and the detection of its immune effect in vivo and vitro.enterhemorrhagic escherichia coli (epec), an important cause of severe infantile diarrheal disease in many parts of the developing world, produced several recently described virulence determinations. several of its virulence factors are secreted by type iii secretion including espa, which forms filamentous structures on bacterial surface bridging to the host cell's surface. these structures on bacterial surfaces may deliver other virulence factors directly into the host cell from ehec. in this s ...201020001787
immune responses elicited in mice with recombinant lactococcus lactis expressing f4 fimbrial adhesin faeg by oral immunization.enterotoxigenic escherichia coli (etec) is a major pathogenic agent causing piglet diarrhea. the major subunit and adhesin faeg of f4(+) etec is an important virulence factor with strong immunogenicity. to determine whether lactococcus lactis (l. lactis) could effectively deliver faeg to the mucosal immune system, recombinant l. lactis expressing faeg was constructed, and immune responses in mice following oral route delivery of recombinant l. lactis were explored. the production of faeg express ...201020532816
origin of the putrescine-producing ability of the coagulase-negative bacterium staphylococcus epidermidis 2015b.a multiplex pcr method, aimed at the detection of genes associated with biogenic amine production, identified the odc gene encoding ornithine decarboxylase in 1 of 15 strains of staphylococcus epidermidis. the ability of the positive strain, s. epidermidis 2015b, to produce putrescine in vitro was demonstrated by high-performance liquid chromatography (hplc). in this strain, the odc gene was detected on plasmid dna, suggesting that the ability to form putrescine is carried by a mobile element, w ...201020581187
metabolic engineering of escherichia coli for the production of succinate from glycerol.glycerol has become an ideal feedstock for the microbial production of bio-based chemicals due to its abundance, low cost, and high degree of reduction. we have previously reported the pathways and mechanisms for the utilization of glycerol by escherichia coli in minimal salts medium under microaerobic conditions. here we capitalize on such results to engineer e. coli for the production of value-added succinate from glycerol. through metabolic engineering of e. coli metabolism, succinate product ...201020601068
uplc/ms based method for quantitative determination of fatty acid composition in gram-negative and gram-positive bacteria.quantitative fatty acid composition of microorganisms at various growth space points is required for understanding membrane associated processes of cells, but the majority of the relevant publications still restrict to the relative compositions. in the current study, a simple and reliable method for quantitative measurement of fatty acid content in bacterial biomass without prior derivatization using ultra performance liquid chromatography-electrospray ionization mass spectrometry was developed. ...201020621131
a novel plasmid for delivering genes into mammalian cells with noninvasive food and commensal lactic acid bacteria.using food and commensal lactic acid bacteria (lab) as vehicles for dna delivery into epithelial cells is a new strategy for vaccine delivery or gene therapy. however, present methods for dna delivery with lab have suffered low efficiency. our goal was to develop a new system to deliver dna into epithelial cells with high efficiency using food and commensal lab. an escherichia coli-lab shuttle plasmid, plkv1, for dna delivery into eukaryotic cells was constructed. two reporter plasmids with gree ...201120832422
screening for antimicrobial resistance genes and virulence factors via genome sequencing.second-generation genome sequencing and alignment of the resulting reads to in silico genomes containing antimicrobial resistance and virulence factor genes were used to screen for undesirable genes in 28 strains which could be used in human nutrition. no virulence factor genes were detected, while several isolates contained antimicrobial resistance genes.201121335393
short communication: characterization of microflora in mexican chihuahua cheese.this work was performed to identify the bacterial species present in 10 chihuahua cheeses obtained from commercial producers in mexico using 16s rrna gene analysis. as expected, some of the agar media initially used for isolation were not very selective, supporting the growth of several unrelated bacterial species. sequence analysis identified potential pathogens, including escherichia coli and staphylococcus aureus, in all raw milk samples and 2 pasteurized milk samples. streptococcus thermophi ...201121700016
biosynthesis of polyhydroxyalkanoates containing 2-hydroxybutyrate from unrelated carbon source by metabolically engineered escherichia coli.we have previously reported in vivo biosynthesis of polylactic acid (pla) and poly(3-hydroxybutyrate-co-lactate) [p(3hb-co-la)] employing metabolically engineered escherichia coli strains by the introduction of evolved clostridium propionicum propionyl-coa transferase (pct( cp )) and pseudomonas sp. mbel 6-19 polyhydroxyalkanoate (pha) synthase 1 (phac1( ps6-19)). using this in vivo pla biosynthesis system, we presently report the biosynthesis of phas containing 2-hydroxybutyrate (2hb) monomer b ...201121842437
construction of theta-type shuttle vector for leuconostoc and other lactic acid bacteria using pcb42 isolated from kimchi.the pcb42 plasmid from leuconostoc citreum cb2567, a strain isolated from kimchi, was characterized, and a shuttle vector for escherichia coli and lactic acid bacteria (lab) was constructed. the pcb42 plasmid has a circular structure of 4312bp, a low g+c content, and no single-stranded dna intermediates during replication, which indicates that pcb42 replicates via the theta-type replication mechanism. in silico analysis of this plasmid revealed 6 open reading frames: 1 transposase gene, 1 dna-bi ...201222133745
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