Plasmid, 1996 Jul, 36(1), 67 - 74 Nucleotide sequence of plasmid p4028, a cryptic plasmid from Leuconostoc oenos; Zuniga M et al.; The Leuconostoc oenos plasmid p4028 was cloned in pBlueScript (SK+), and its complete nucleotide sequence was determined . The analysis of the nucleotide sequence revealed five open reading frames, all of them located on the same strand and grouped in two clusters separated by a short noncoding stretch . A similarity search against the other sequences deposited in the EMBL and GenBank databases showed that p4028 has no significant similarity with any of the sequences checked . Nevertheless, a putative ATP-binding motif was found in ORF2 . A more detailed analysis of this ORF suggests that it could encode for a DNA-dependent ATPase. Free Radic Res, 1996 Jul, 25(1), 23 - 9 Determination of site-specific modifications of glucose-6-phosphate dehydrogenase by 4-hydroxy-2-nonenal using matrix assisted laser desorption time-of-flight mass spectrometry; Grace JM et al.; Products of the reaction of 4-hydroxy-2-nonenal (4HNE) with native and heat-denatured Leuconostoc mesenteroides glucose-6-phosphate dehydrogenase (G6PDH) were analyzed to determine the structure and position of the protein modifications . Matrix assisted laser desorption time-of-flight mass spectrometry was used to measure molecular weights of the modified proteins and determine mass maps of peptides formed by digestion with cyanogen bromide . The molecular weight data show that one to two 4HNE molecules add to each subunit of native enzyme while approximately nineteen 4HNE molecules add to each subunit of heat-denatured enzyme . Peptides are observed in the cyanogen bromide mass map of modified native G6PDH that are consistent with selective modification of two segments of the amino acid sequence . One modified segment contains Lysine-182 that has been found to be part of the enzyme active site . Peptides are observed in the cyanogen bromide mass map of modified heat-denatured enzyme that are consistent with extensive modification of several segments of the amino acid sequence . The magnitude of the mass differences between modified and unmodified peptides were approximately 156 Da, consistent with a 1,4-addition of 4HNE . These results support the conclusion that 4HNE inactivates G6PDH by selectively modifying only two or three sites in the protein by a 1,4-addition reaction and that some aspect of the tertiary structure of the enzyme directs those modification reactions. J Bacteriol, 1996 Jun, 178(11), 3127 - 32 The proton motive force generated in Leuconostoc oenos by L-malate fermentation; Salema M et al.; In cells of Leuconostoc oenos, the fermentation of L-malic acid generates both a transmembrane pH gradient, inside alkaline, and an electrical potential gradient, inside negative . In resting cells, the proton motive force ranged from -170 mV to -88 mV between pH 3.1 and 5.6 in the presence Of L-malate . Membrane potentials were calculated by using a model for probe binding that accounted for the different binding constants at the different pH values at the two faces of the membrane . The delta psi generated by the transport of monovalent malate, H-malate-, controlled the rate of fermentation . The fermentation rate significantly increased under conditions of decreased delta psi, i.e., upon addition of the ionophore valinomycin in the presence of KCl, whereas in a buffer depleted of potassium, the addition of valinomycin resulted in a hyperpolarization of the cell membrane and a reduction of the rate of fermentation . At the steady state, the chemical gradient for H-malate- was of the same magnitude as delta psi . Synthesis of ATP was observed in cells performing malolactic fermentation. FEMS Microbiol Lett, 1996 May 1, 138(2-3), 251 - 9 The putative immunity protein of the gram-positive bacteria Leuconostoc mesenteroides is preferentially located in the cytoplasm compartment; Dayem MA et al.; Immunity proteins are though to protect bacteriocin-producing bacterial strains against the bactericidal effects of their own bacteriocin . The immunity protein which protects the lactic acid bacterium Leuconostoc mesenteroides against mesentericin Y105(37) bacteriocin was detected and localized by immunofluorescence and electron microscopy, using antibodies directed against the C-terminal end of the predicted immunity protein . The antibodies recognized the immunity proteins of various strains of Leuconostoc, including Leuconostoc mesenteroides and Leuconostoc gelidum . This study demonstrated that immunity proteins produced by Leuconostoc mesenteroides accumulated in the cytoplasmic compartment of the bacteria . This is in contrast with other known immunity proteins, such as the colicin immunity proteins, which are integral membrane proteins possessing three to four transmembrane domains. Blood, 1996 Apr 1, 87(7), 2974 - 82 Glucose 6-phosphate dehydrogenase mutations causing enzyme deficiency in a model of the tertiary structure of the human enzyme; Naylor CE et al.; Human glucose 6-phosphate dehydrogenase (G6PD) has a particularly large number of variants resulting from point mutations; some 60 mutations have been sequenced to date . Many variants, some polymorphic, are associated with enzyme deficiency . Certain variants have severe clinical manifestations; for such variants, the mutant enzyme almost always displays a reduced thermal stability . A homology model of human G6PD has been built, based on the three-dimensional structure of the enzyme from Leuconostoc mesenteroides . The model has suggested structural reasons for the diminished enzyme stability and hence for deficiency . It has shown that a cluster of mutations in exon 10, resulting in severe clinical symptoms, occurs at or near the dimer interface of the enzyme, that the eight-residue deletion in the variant Nara is at a surface loop, and that the two mutations in the A- variant are close together in the three-dimensional structure. Arch Biochem Biophys, 1996 Apr 1, 328(1), 158 - 64 Chemical characterization of a protein-4-hydroxy-2-nonenal cross-link: immunochemical detection in mitochondria exposed to oxidative stress; Cohn JA et al.; We have previously shown that incubation of the model protein glucose-6-phosphate dehydrogenase (Glu-6-PDH) from the bacterium Leuconostoc mesenteroides with 4-hydroxy-2-nonenal (HNE), a major product of lipid peroxidation, results in the formation of cross-linked protein . HNE-modified protein is resistant to proteolytic degradation and acts as an inhibitor of the multicatalytic proteinase . It was therefore important to establish the chemistry of the cross-linking reaction . The formation of cross-linked Glu-6-PDH is associated with the nearly exclusive loss of lysine residues . For this reason the reaction of N-acetyllysine with HNE has been investigated . The epsilon-amino group of lysine reacts with the double bond (C3) and the carbonyl (C1) functions of HNE via Michael addition and Schiff base formation resulting in the production of a 2:1 amino acid-HNE cross-link . Chromatographic detection of this adduct in the acid hydrolysate of HNE-treated Glu-6-PDH reveals that this chemistry is responsible for the formation of cross-linked protein . Antibody to the reduced form of the 2:1 lysine-HNE adduct was prepared . The antibody was used to demonstrate that exposure of isolated liver mitochondria to oxidative stress led to the formation of intra- and intermolecular protein-HNE cross-links . The results of the present study indicate that modifications to protein by lipid peroxidation products may be physiologically relevant and could contribute to the disease- and age-related buildup of damaged protein. J Bacteriol, 1996 Apr, 178(8), 2178 - 85 Proton motive force generation by citrolactic fermentation in Leuconostoc mesenteroides; Marty-Teysset C et al.; In Leuconostoc mesenteroides subsp . mesenteroides 19D, citrate is transported by a secondary citrate carrier (CitP) . Previous studies of the kinetics and mechanism of CitP performed in membrane vesicles of L . mesenteroides showed that CitP catalyzes divalent citrate HCit2-/H+ symport, indicative of metabolic energy generation by citrate metabolism via a secondary mechanism (C . Marty-Teysset, J . S . Lolkema, P . Schmitt, C . Divies, and W . N . Konings, J . Biol . Chem . 270:25370-25376, 1995) . This study also revealed an efficient exchange of citrate and D-lactate, a product of citrate/carbohydrate cometabolism, suggesting that under physiological conditions, CitP may function as a precursor/product exchanger rather than a symporter . In this paper, the energetic consequences of citrate metabolism were investigated in resting cells of L . mesenteroides . The generation of metabolic energy in the form of a pH gradient (delta pH) and a membrane potential (delta psi) by citrate metabolism was found to be largely dependent on cometabolism with glucose . Furthermore, in the presence of glucose, the rates of citrate utilization and of pyruvate and lactate production were strongly increased, indicating an enhancement of citrate metabolism by glucose metabolism . The rate of citrate metabolism under these conditions was slowed down by the presence of a membrane potential across the cytoplasmic membrane . The production of D-lactate inside the cell during cometabolism was shown to be responsible for the enhancement of the electrogenic uptake of citrate . Cells loaded with D-lactate generated a delta psi upon dilution in buffer containing citrate, and cells incubated with citrate built up a pH gradient upon addition of D-lactate . The results are consistent with an electrogenic citrate/D-lactate exchange generating in vivo metabolic energy in the form of a proton electrochemical gradient across the membrane . The generation of metabolic energy from citrate metabolism in L . mesenteroides may contribute significantly to the growth advantage observed during cometabolism of citrate and glucose. Biosci Biotechnol Biochem, 1996 Feb, 60(2), 319 - 21 Screening for bacteria producing sucrose phosphorylase and characterization of the enzymes; Kawasaki H et al.; Two microbial strains, No . 165 and No . 168, were isolated from soil as sucrose phosphorylase producers and identified as Leuconostoc mesenteroides subsp . mesenteroides and subsp . dextranicum, respectively . The sucrose phosphorylases were purified, characterized, and compared with the enzymes of L . mesenteroides AKU1102 and ATCC12291 . As for the catalytic properties, these enzymes were close to each other, while as for the enzyme molecules, the No . 165 enzyme (Mr: 58,000) was slightly different from the other (Mr: 54,000), though their N-terminal amino acid sequences were almost the same. Arch Biochem Biophys, 1996 Feb 1, 326(1), 145 - 51 Identification of an arginine residue in the dual coenzyme-specific glucose-6-phosphate dehydrogenase from Leuconostoc mesenteroides that plays a key role in binding NADP+ but not NAD+; Levy HR et al.; Glucose-6-phosphate dehydrogenase from Leuconostoc mesenteroides can utilize either NADP or NAD as coenzyme . The enzyme's three-dimensional structure has been solved (Rowland et al., 1994, Structure 2, 1073-1087) and shown to contain a conventional nucleotide binding domain . NADP+ was modeled into the structure by superimposing the beta alpha beta domain and that of coenzyme-bound 6-phosphogluconate dehydrogenase (Adams et al., 1994, Structure 2, 651-658), enabling us to identify Arg-46 as a potentially important residue for NADP+ binding . Using site-directed mutagenesis, we constructed mutant enzymes in which Arg-46 was replaced by glutamine (R46Q) and alanine (R46A) and examined their kinetic properties . The principal effects in these mutant enzymes were that the Km and Ki values for NADP+ increased by 2 to 3 orders of magnitude over those of the wild-type enzyme . No other kinetic constant was altered more than 6.5-fold . Changing this single amino acid leads to mutant glucose-6-phosphate dehydrogenases with coenzyme specificities that favor NAD+, whereas the wild-type enzyme prefers NADP+ as coenzyme . These results confirm that Arg-46 plays a key role in NADP+ binding by contributing a positively charged planar residue that interacts primarily with the 2'-adenosine phosphate . The Arg residue corresponding to Arg-46 in L . mesenteroides glucose-6-phosphate dehydrogenase is conserved in all glucose-6-phosphate dehydrogenases and, presumably, plays the same role in all these enzymes. Int J Food Microbiol, 1996 Jan, 28(3), 361 - 7 Sapal: a traditional fermented taro {Colocasia esculenta (L.) Schott} corm and coconut cream mixture from Papua New Guinea; Gubag R et al.; Sapal is a traditional fermented food made by mixing cooked, grated taro {Colocasia esculenta (L.) Schott} corm with coconut cream and allowing it to ferment at ambient temperature . The fermentation was primarily due to heterofermentative lactic acid bacteria, which reached 10(10) cfu/ml . Seven out of 10 isolated bacterial strains were identified as Leuconostoc mesenteroides or Leuc . paramesenteroides . The initial microbial flora was derived from the coconut cream . Yeasts grew on the surface of the sapal in the later stages of the fermentation . Overnight storage of the grated taro corm resulted in the glucose concentration increasing from 1.1 to about 5 g/l . During the fermentation the glucose concentration decreased to undetectable levels . The pH value fell from an initial value of 6.1 to 4.1 after 24 h. J Biol Chem, 1995 Oct 27, 270(43), 25370 - 6 Membrane potential-generating transport of citrate and malate catalyzed by CitP of Leuconostoc mesenteroides; Marty-Teysset C et al.; Citrate uptake in Leuconostoc mesenteroides subsp . mesenteroides 19D is catalyzed by a secondary citrate carrier (CitP) . The kinetics and mechanism of CitP were investigated in membrane vesicles of L . mesenteroides . The transporter is induced by the presence of citrate in the medium and transports both citrate and malate . In spite of sequence homology to the Na(+)-dependent citrate carrier of Klebsiella pneumoniae, CitP is not Na(+)-dependent, nor is CitP Mg(2+)-dependent . The pH gradient (delta pH) is a driving force for citrate and malate uptake into the membrane vesicles, whereas the membrane potential (delta psi) counteracts transport . An inverted membrane potential (inside positive) generated by thiocyanide diffusion can drive citrate and malate uptake in membrane vesicles . Analysis of the forces involved showed that a single unit of negative charge is translocated during transport . Kinetic analysis of citrate counterflow at different pH values indicated that CitP transports the dianionic form of citrate (Hcit2-) with an affinity constant of approximately 20 microns . It is concluded that CitP catalyzes Hcit2-/H+ symport . Translocation of negative charge into the cell during citrate metabolism results in the generation of a membrane potential that contributes to the protonmotive force across the cytoplasmic membrane, i.e . citrate metabolism in L . mesenteroides generates metabolic energy . Efficient exchange of citrate and D-lactate, a product of citrate/carbohydrate co-metabolism, is observed, suggesting that under physiological conditions, CitP may function as an electrogenic precursor/product exchanger rather than a symporter . The mechanism and energetic consequences of citrate uptake are similar to malate uptake in lactic acid bacteria. FEMS Microbiol Lett, 1995 Aug 15, 131(1), 57 - 62 Expression of DnaK and GroEL homologs in Leuconostoc esenteroides in response to heat shock, cold shock or chemical stress; Salotra P et al.; The mechanism of adaptation of bacteria to survive at elevated temperature in the human host and the expression of heat-shock proteins in response to stress was examined by labelling with {35S}methionine . An increase in culture temperature from 26 degrees C to 37 degrees C induced expression of certain bacterial proteins (70 and 60 kDa) . Heat shock at 40 degrees C, cold shock (10 degrees C), ethanol treatment or arsenite treatment also led to an increased expression of heat shock proteins of 70 and 60 kDa . Actinomycin D completely blocked the induction, indicating that transcription is required for the overexpression of stress proteins in Leuconostoc mesenteroides . N-terminal sequence analysis showed that these proteins were homologous to the highly conserved chaperone proteins DnaK and GroEL of Escherichia coli, respectively. Int J Food Microbiol, 1995 Aug, 26(3), 345 - 52 Differentiation of dextran-producing Leuconostoc strains from fermented rice cake (puto) using pulsed-field gel electrophoresis; Kelly WJ et al.; Lactic acid bacteria were isolated from puto, a fermented rice cake consumed as a breakfast and snack food in the Philippines . The microflora was dominated by dextran-producing leuconostocs, and these were differentiated into four groups using pulsed-field gel electrophoresis of restriction enzyme digested chromosomal DNA, in conjunction with taxonomic tests . The four groups corresponded to the species Leuconostoc mesenteroides subsp . mesenteroides, Leuconostoc pseudomesenteroides, Leuconostoc citreum and Leuconostoc fallax . Several strains showed an unusual clumping phenotype, and two of these were capable of inhibiting other strains of lactic acid bacteria. Biochem Mol Biol Int, 1995 Jul, 36(3), 639 - 47 2,4,6-Trinitrobenzenesulphonic acid as a probe for lysine at the active site of dextransucrase from Leuconostoc mesenteroides NRRL B-512F; Goyal A et al.; Modification of Leuconostoc mesenteroides NRRL B-512F dextransucrase with 2,4,6-trinitrobenzenesulphonic acid (TNBS) at pH 5.2 and 30 degrees C resulted in the loss of enzyme activity . The kinetic profiles of inactivation showed that the reaction followed pseudo-first order reaction . Absorption spectra of TNBS modified enzyme gave characteristic maxima at 367 nm . The inactivation could not be reversed by dilution or dialysis . The substrate sucrose, provided protection to the enzyme against inactivation by TNBS, indicating that the essential residues are present at or near the active site . The stoichiometric results indicated that four mol of lysine are modified per mol of dextransucrase upon complete inactivation . However, more than 50% of the activity loss was accompanied by modification of 1 lysine residue . All these approaches suggested that one lysine residue present near or at the active site is essential for the enzymatic activity of dextransucrase. Biochem Mol Biol Int, 1995 Jul, 36(3), 579 - 85 Involvement of a lysine residue in the inactivation of Leuconostoc mesenteroides NRRL B-512F dextransucrase by o-phthalaldehyde; Goyal A et al.; Leuconostoc mesenteroides NRRL B-512F dextransucrase was rapidly and irreversibly inactivated by o-phthalaldehyde . The dextransucrase-o-phthalaldehyde adduct showed a characteristic fluorescence maxima at 417 nm when excited at 337 nm . These results were consistent with the isoindole derivative formation in which the sulfhydryl group of cysteine and epsilon-amino group of lysine participate in the reaction . The stoichiometric determinations gave one isoindole derivative per enzyme molecule upon complete inactivation by o-phthalaldehyde . The enzyme showed no inhibition on treatment with thiol specific reagents . This indicated that cysteine is present in close proximity of the lysine and is involved in the isoindole derivative formation but is not participating in the catalysis . These results established for the first time that one lysine residue present at the active site is required for the activity of dextransucrase. Lett Appl Microbiol, 1995 May, 20(5), 268 - 70 Isolation of a dextranase constitutive mutant of Lipomyces starkeyi and its use for the production of clinical size dextran; Kim D et al.; A derepressed and partially constitutive mutant for dextranase of Lipomyces starkeyi was selected after ethyl methane sulphonate mutagenesis by zone clearance on blue dextran agar plates . The mutant produced dextranase when grown on glucose, fructose and sucrose as well as on dextran, and more enzyme was produced by the mutant than by the parental strain when grown on 1% dextran . The pH and temperature optima for the mutant dextranase were 5.5 and 55 degrees C, respectively . Dextranase produced on sucrose produced more isomaltose and less glucose after dextran hydrolysis than the equivalent enzyme produced on dextran . The clinical size dextran (average mol . wt of 75,000 +/- 25,000) yield of mixed culture fermentation with the mutant and Leuconostoc mesenteroides was 94% of the total dextran produced. Res Microbiol, 1995 May, 146(4), 291 - 302 Purification, properties and DNA sequence of the D-lactate dehydrogenase from Leuconostoc mesenteroides subsp . cremoris; Dartois V et al.; The complete sequence of the D-lactate dehydrogenase (D-ldh) gene from Leuconostoc mesenteroides subsp . cremoris, cloned in Escherichia coli, were determined . The deduced amino acid sequence showed homologies with all members of the D-specific-2-hydroxyacid dehydrogenase family . Furthermore, the essential residues detected so far as being involved in catalysis were also conserved . Purification of the enzyme revealed physico-chemical properties corresponding to those predicted from the sequence . The active enzyme was a dimer of 40-kDa subunits . The Km values for pyruvate, lactate, NADH and NAD were 0.3, 19, 0.03 and 0.16 mM, indicating that the enzyme reduced pyruvate in vivo . Besides the D-LDH activity, L . mesenteroides subsp . cremoris also displayed HicDH enzymatic activity, catalysing the reduction of pyruvate analogs . The purified D-LDH displayed low HicDH-type activity; therefore, differences in specificity profiles between the crude extract and the purified enzyme suggested the occurrence of a specific HicDH. Biosci Biotechnol Biochem, 1995 May, 59(5), 776 - 80 Aggregated form of dextransucrases from Leuconostoc mesenteroides NRRL B-512F and its constitutive mutant; Funane K et al.; Purified dextransucrases {EC 2.4.1.5}, DSW-D and DSW-G, from Leuconostoc mesenteroides B-512F were obtained from affinity chromatography with DEAE-Sephadex A-50 by elution with clinical dextran and guanidine-HCl, respectively . DSM-G was purified from the B-512F mutant strain SH 3002, which produces dextransucrase constitutively . Although the sugar contents of the purified enzymes were different, their molecular masses by SDS-PAGE were all 170 kDa . DSW-D and DSW-G were highly aggregated and the all the activities were eluted at the void volume (V0) on Sepharose 6B, while the DSM-G was eluted at 1.2 x V0 volume . On rechromatography, DSM-G was separated into three peaks corresponding to the aggregated form, monomeric form, and partially digested form, respectively . The aggregation of Leuconostoc dextransucrase was looser than that of streptococcal glucosyltransferases, but the structures of these enzymes had high homology with each other. J Clin Microbiol, 1995 Apr, 33(4), 885 - 7 Evaluation of three disk tests for identification of enterococci, leuconostocs, and pediococci; Facklam R et al.; Simple rapid tests for presumptive identification of catalase-negative non-beta-hemolytic cocci (i.e., enterococci, leuconostocs, and pediococci) have not previously been available . Seven hundred thirty-four strains of aerobic and facultatively anaerobic, catalase-negative, non-beta-hemolytic gram-positive cocci were tested for susceptibility to vancomycin (Vans) by a screening procedure and production of leucine aminopeptidase (LAPase) and pyrrolidonylarylamidase (PYRase) in disk tests . Three unique patterns of activity in response to the three disks (30 micrograms of vancomycin, PYRase, and LAPase) can be used to presumptively identify the vancomycin-resistant (Vanr) enterococci (Vanr and PYRase and LAPase positive), leuconostocs (Vanr and PYRase and LAPase negative), and pediococci (Vanr, PYRase negative, and LAPase positive) . The results indicate that, together with Gram stain characteristics and the catalase test, the vancomycin, LAPase, and PYRase disk tests can be used to presumptively identify Vanr strains of enterococci as well as Leuconostoc and Pediococcus strains from human infections. Int J Syst Bacteriol, 1995 Apr, 45(2), 395 - 7 Proposal to reclassify Leuconostoc oenos as Oenococcus oeni {corrig.} gen . nov., comb . nov.; Dicks LM et al.; Wine strains belonging to the genus Leuconostoc were classified as Leuconostoc oenos by Garvie in 1967, and this name was confirmed on the Approved Lists of Bacterial Names in 1980 . L . oenos is distinguished from other Leuconostoc spp . by its growth in acidic media, by its requirement for a growth factor in tomato juice, and by a number of carbohydrate fermentation characteristics . In addition, the results of a total soluble cell protein analysis, an electrophoretic analysis of NAD-dependent D-(-)-lactate dehydrogenase, 6-phosphogluconate dehydrogenase, and alcohol dehydrogenase, and an analysis of cross-reactivity with anti-glucose-6-phosphate dehydrogenase and anti-NAD-dependent D-(-)-lactate dehydrogenase performed with other Leuconostoc spp . clearly indicated that L . oenos should be distinguished from the other Leuconostoc species . Phylogenetic studies, in particular 16S and 23S rRNA sequencing studies, have revealed that L . oenos represents a distinct subline that is separate from other Leuconostoc spp . and lactic acid bacteria . In view of the phenotypic and phylogenetic distinctiveness of L . oenos, we propose that this species should be assigned to a new genus as Oenococcus oeni {corrig.} gen . nov., comb . nov . The type strain of O . oeni is NCDO 1674 (= ATCC 23179). Lett Appl Microbiol, 1995 Apr, 20(4), 204 - 8 Detection of dairy Leuconostoc strains using the polymerase chain reaction; Ward LJ et al.; This paper reports the design of a Leuconostoc-specific oligonucleotide based on 16S rRNA sequence data . When this oligonucleotide was used in a polymerase chain reaction (PCR) in conjunction with an oligonucleotide to a conserved region of the 16S rRNA sequence, a Leuconostoc-specific PCR product of approximately 470 bp was produced . The use of a second oligonucleotide to a conserved region allowed the production of an approximately 350 bp product in all PCRs, acting as a positive control . The PCR procedure described was particularly useful for detecting the presence of Leuconostoc in mixed mesophilic starter cultures . The Leuconostoc-specific oligonucleotide was used also as a specific hybridization probe. Antimicrob Agents Chemother, 1995 Feb, 39(2), 362 - 8 Heterogeneity of the vanA gene cluster in clinical isolates of enterococci from the northeastern United States; Handwerger S et al.; In several strains of Enterococcus faecium isolated in Europe, the cluster of genes encoding high-level resistance to vancomycin (VanA phenotype) resides on a 10.85-kb transposon, Tn1546, or closely related elements . To determine whether Tn1546 was conserved in recent enterococcal isolates from the northeastern United States, seven strains were compared by restriction mapping and DNA hybridization with probes from within the van cluster . Two of the seven strains contained intact Tn1546-like sequences; however, in five of the strains, the organization of the van cluster differed from that of Tn1546 . Three of the five strains with variations harbored a novel DNA segment within the van gene cluster . This 1,496-bp segment was similar to IS1165 of Leuconostoc mesenteroides and IS1181 of Staphylococcus aureus and was flanked by 24- and 23-bp imperfect inverted repeats and 8-bp direct repeats . On the basis of these findings, we propose that this element comprises a novel insertion-like sequence, IS1251 . Multiple copies of IS1251 were also present at other sites in both resistant and susceptible clinical isolates . Our findings suggest that the van cluster in recent isolates from the northeastern United States differs from that present in the early European VanA phenotype strains. J Enzyme Inhib, 1995, 8(4), 291 - 5 Inactivation of Leuconostoc mesenteroids NRRL B-512F dextransucrase by specific modification of lysine residues with pyridoxal-5'-phosphate; Goyal A et al.; Dextransucrase from Leuconostoc mesenteroides NRRL B-512F was inactivated by pyridoxal-5'-phosphate (PLP) . The inactivation was reversible in as much as the loss of enzyme activity was completely reversed by prolonged dialysis . PLP-modified dextransucrase after reduction with sodium borohydride showed a characteristic fluorescence emission maximum at 397 nm when excited at 325 nm . The stoichiometric results indicated that four lysine residues are modified by PLP under the experimental conditions . These results established for the first time that lysine residues are essential for the activity of dextransucrase. Eur J Biochem, 1994 Dec 1, 226(2), 641 - 8 Enzymically produced cyclic alpha-1,3-linked and alpha-1,6-linked oligosaccharides of D-glucose; Cote GL et al.; A new type of bacterial enzyme hydrolyzed alternan (Leuconostoc mesenteroides NRRL B-1355 fraction S dextran, an alternating alpha-1,3-alpha-1,6-D-glucan) to give rise to a series of oligosaccharides . The oligosaccharide formed in the greatest proportion was a cyclic tetrasaccharide of D-glucosyl residues linked in an alternating alpha-1,3-alpha-1,6 fashion . Other saccharide products included isomaltose and alpha-D-glucopyranosyl-1,3-alpha-D-glucopyranosyl-1,6-D-glucose . Oligosaccharides of higher degrees of polymerization were also formed, and included alpha-D-glucosylated derivatives of the cyclic tetrasaccharide . This is the first report of a naturally produced cyclic tetrasaccharide. Eur J Biochem, 1994 Dec 1, 226(2), 633 - 9 Purification and properties of alternanase, a novel endo-alpha-1,3-alpha-1,6-D-glucanase; Biely P et al.; A newly isolated soil bacterium strain NRRL B-21195, tentatively identified as a Bacillus species, was found to be a constitutive producer of a novel type of glycanase that hydrolyses in an endo-fashion the polysaccharide alternan, an alpha-1,3-alpha-1,6-D-glucan, referred to in the literature as B-1355 dextran (fraction S), synthesized from sucrose by alternansucrase of Leuconostoc mesenteroides . The glycanase, named alternanase, has been purified to homogeneity from a cell-free culture fluid of the bacillus grown in a liquid medium containing D-glucose, and has been characterized . The enzyme has a molecular mass of 110000 Da (SDS/PAGE) and an isoelectric point of approximately 4.0 . Optimum activity occurs at pH 7 and at a temperature of 40 degrees C . The enzyme is stable up to 50 degrees C but loses activity rapidly at 60 degrees C . Its action is inhibited by EDTA and stimulated by Ca2+ . The enzyme requires, for its action, D-glucan chains in which alpha-1,3-linkages alternate with alpha-1,6-linkages; i.e., it is specific for alternan . Monitoring of alternan hydrolysis by determination of liberated reducing sugars pointed to an unusually low extent of hydrolysis and a low specific activity of the enzyme . As shown in the accompanying paper {Cote, G . L . & Biely, P . (1994) Eur . J . Biochem . 226, 641-648} the reason for this finding is that the main hydrolytic products are non-reducing, novel types of cyclic oligosaccharides. Enzyme Microb Technol, 1994 Dec, 16(12), 1010 - 5 Properties of Leuconostoc mesenteroides B-512FMC constitutive dextransucrase; Kim D et al.; Leuconostoc mesenteroides B-512FMC, a constitutive mutant for dextransucrase, was grown on glucose, fructose, or sucrose . The amount of cell-associated dextransucrase was about the same for the three sugars at different concentrations (0.6% and 3%) . Enzyme produced in glucose medium was adsorbed on Sephadex G-100 and G-200, but much less enzyme was adsorbed when it was produced in sucrose medium . Sephadex adsorption decreased when the glucose-produced enzyme was preincubated with dextrans of molecular size greater than 10 kDa . The release of dextransucrase activity from Sephadex by buffer (20 mM acetate, pH 5.2) was the highest at 28 degrees-30 degrees C . The addition of dextran to the enzyme stimulated dextran synthesis but had very little effect on the temperature or pH stability . Dextransucrase purified by ammonium sulfate precipitation, hydroxyapatite chromatography, and Sephadex G-200 adsorption did not contain any carbohydrate, and it synthesized dextran, showing that primers are not necessary to initiate dextran synthesis . The purified enzyme had a molecular size of 184 kDa on SDS-PAGE . On standing at 4 degrees C for 30 days, the native enzyme was dissociated into three inactive proteins of 65, 62, and 57 kDa . However, two protein bands of 63 and 59 kDa were obtained on SDS-PAGE after heat denaturation of the 184-kDa active enzyme at 100 degrees C . The amount of 63-kDa protein was about twice that of 59-kDa protein . The native enzyme is believed to be a trimer of two 63-kDa and one 59-kDa monomers. Int J Food Microbiol, 1994 Dec, 24(1-2), 75 - 81 Bacteriocins of leuconostocs isolated from meat; Hastings JW et al.; Several bacteriocin-producing Leuconostoc strains have been isolated from meat and identified as Leuconostoc gelidum UAL 187, Leuconostoc paramesenteroides-La7a, Leuconostoc carnosum-Ta11a and Leuconostoc carnosum-La54a . All strains produce bacteriocins that are active against Listeria monocytogenes and other lactic acid bacteria of concern in meat spoilage . All of the bacteriocins studied are heat stable in acidic environments and are inactivated by a range of proteolytic enzymes but not by catalase or lysozyme . Most are detected early in the growth cycle and are produced at refrigeration temperatures and in a pH range of 4.0-7.0 . Leucocin A-UAL187, produced by Leuconostoc gelidium UAL 187, is a small peptide (MW 3930) translated as a 61 amino acid prepeptide consisting of a 24 amino acid leader region and 37 amino acid active bacteriocin that is secreted . A probe designed from a region of the leucocin gene has been used to locate the bacteriocin genes in the other strains (La7a, La54a and Ta11a) . Strong hybridization signals were detected from 8.9 MDa, 32 MDa and 8.9 MDa plasmids in strains La7a, La54a and Ta11a, respectively . The bacteriocin structural gene from Leuconostoc carnosum-Ta11a (leucocin B-Ta11a) has been cloned and sequenced and the bacteriocin shows 100% homology to leucocin A-UAL187; however, the prepeptide differs in six residues . The mature extracellular bacteriocin from strain UAL 187 was purified and characterized by precipitation, gel filtration, hydrophobic interaction chromatography followed by RP-HPLC and amino-terminal sequencing, whilst those of the other strains are in the process of being purified and characterized using similar techniques.(ABSTRACT TRUNCATED AT 250 WORDS) Structure, 1994 Nov 15, 2(11), 1073 - 87 The three-dimensional structure of glucose 6-phosphate dehydrogenase from Leuconostoc mesenteroides refined at 2.0 A resolution; Rowland P et al.; BACKGROUND: Glucose 6-phosphate dehydrogenase (G6PD) is the first enzyme of the pentose phosphate pathway . Normally the pathway is synthetic and NADP-dependent, but the Gram-positive bacterium Leuconostoc mesenteroides, which does not have a complete glycolytic pathway, also uses the oxidative enzymes of the pentose phosphate pathway for catabolic reactions, and selects either NAD or NADP depending on the demands for catabolic or anabolic metabolism . RESULTS: The structure of G6PD has been determined and refined to 2.0 A resolution . The enzyme is a dimer, each subunit consisting of two domains . The smaller domain is a classic dinucleotide-binding fold, while the larger one is a new beta+ alpha fold, not previously seen, with a predominantly antiparallel nine-stranded beta-sheet . There are significant structural differences in the coenzyme-binding domains of the two subunits, caused by Pro 149 which is cis in one subunit and trans in the other . CONCLUSIONS: The structure has allowed us to propose the location of the active site and the coenzyme-binding site, and suggests the role of many of the residues conserved between species . We propose that the conserved Arg46 would interact with both the adenine ring and the 2'-phosphate of NADP . Gln47, which is not conserved, may contribute to the change from NADP to dual coenzyme specificity . His178, in a nine-residue peptide conserved for all known sequences, binds a phosphate in the active site pocket . His240 is the most likely candidate for the base to oxidize the 1-hydroxyl group of the glucose 6-phosphate substrate. Gene, 1994 Oct 11, 148(1), 125 - 9 Cloning, sequence and in vitro transcription/translation analysis of a 3.2-kb EcoRI-HindIII fragment of Leuconostoc oenos bacteriophage L10; Sutherland M et al.; A 3.2-kb EcoRI-HindIII DNA fragment of Leuconostoc oenos bacteriophage L10 was cloned and sequenced . Computer-assisted analysis of the sequence identified eleven possible open reading frames (ORFs) that were all on the same strand . In vitro transcription/translation analysis of the full-length DNA fragment yielded five prominent proteins that were correlated with ORFs by their sizes and expression from deleted clones . Only those ORFs containing recognizable Shine-Dalgarno sequences coded for proteins . Neither the nucleotide sequence, nor deduced amino-acid sequences showed significant homology with other known sequences. J Appl Bacteriol, 1994 Oct, 77(4), 401 - 7 Histamine production by wine lactic acid bacteria: isolation of a histamine-producing strain of Leuconostoc oenos; Lonvaud-Funel A et al.; Populations of Leuconostoc oenos were harvested from wines containing a relatively high concentration of biogenic amines . Cultivation of the biomass in synthetic media and wine showed that it consisted of histamine-producing strains . Histamine levels after culture depended on the quantity of precursor available and on the presence of yeast lees, which certainly enriched the medium in histidine . Ethanol and pH, which control bacterial growth rate and total population, were also significant factors: pH and low ethanol concentration enhanced histamine production . Strain Leuc . oenos 9204 was isolated and studied since it retained its ability to produce histamine after several transfers . In synthetic medium this strain produced large amounts of histamine especially in the poorest nutritional conditions (no glucose, no L-malic acid) . These results clearly demonstrate that Leuc . oenos involved in wine-making might play a role in biogenic amine production . The vinification method might also influence the final amine concentration in wine. Eur J Biochem, 1994 Oct 1, 225(1), 289 - 95 Uniport of monoanionic L-malate in membrane vesicles from Leuconostoc oenos; Salema M et al.; L-malate transport was studied in membrane vesicles from Leuconostoc oenos MLE(-) (mutant lacking malolactic enzyme) which were fused with liposomes containing beef heart cytochrome c oxidase as a proton-motive-force-generating system . In these hybrid membranes, accumulation of L-malate was observed in response to a pH gradient (delta pH), with the inside alkaline, but was strongly inhibited by a membrane potential (delta psi) of normal polarity (inside negative) . Imposition of a delta psi, with the inside positive, by means of valinomycin-mediated potassium influx, resulted in a rapid accumulation of L-malate, indicating that L-malate was taken up in an anionic form . The results are consistent with a uniport mechanism facilitating the uptake of monoanionic L-malate, the dominant species at the low pH of the experiments . Kinetic analysis of delta pH-driven L-malate uptake in the pH range 3.0-5.8, yielded apparent affinity constants that varied less than twofold when calculated on the basis of the concentrations of monoanionic L-malate, whereas the values differed 2-3 orders of magnitude for the other species . At L-malate concentrations above 1 mM, a non-saturable transport component became apparent which may reflect passive influx of L-malic acid . Substrate specificity studies indicated that citrate and L-malate (and possibly D-lactate and L-lactate) compete for a single general carboxylate transport system . The carboxylate transport system catalysed homologous L-malate and heterologous L-malate/citrate exchange with rates similar to the rate of L-malate efflux . Since metabolic energy is conserved during malolactic fermentation in L . oenos, the underlying mechanism most likely involves electrogenic monoanionic L-malate uptake, in combination with H+ consumption in the cytoplasm, followed by diffusion outwards of lactic acid plus carbon dioxide. Curr Microbiol, 1994 Oct, 29(4), 207 - 12 Characterization of leucocin B-Ta11a: a bacteriocin from Leuconostoc carnosum Ta11a isolated from meat; Felix JV et al.; Leuconostoc (Lc.) carnosum Ta11a, isolated from vacuum-packaged processed meats, produced a bacteriocin designated leucocin B-Ta11a . The crude bacteriocin was heat stable and sensitive to proteolytic enzymes, but not to catalase, lysozyme, or chloroform . It was active against Listeria monocytogenes and several lactic acid bacteria . Leucocin B-Ta11a was optimally produced at 25 degrees C in MRS broth at an initial pH of 6.0 or 6.5 . An 8.9-MDa plasmid in Leuconostoc carnosum Ta11a hybridized to a 36-mer oligonucleotide probe (JF-1) that was homologous to leucocin A-UAL187 . A 4.9-kb Sau3A fragment from a partial digest of the 8.9-MDa plasmid was cloned into pUC118 . The 8.1-kb recombinant plasmid (pJF8.1) was used for sequencing and revealed the presence of two open reading frames (ORFs) . ORF1 codes for a protein of 61 amino acids comprising a 37-amino-acid bacteriocin that was determined to be the leucocin B-Ta11a structural gene by virtue of its homology to leucocin A-UAL 187 (Hastings et al . 1991 . J . Bacteriol 173:7491-7500) . The 24-amino-acid N-terminal extension, however, differs from that of leucocin A-UAL187 by seven residues . The predicted protein of the ORF2 has 113 amino acids and is identical with the amino acid sequence of the cognate ORF of the leucocin A-UAL 187 operon. Enzyme Microb Technol, 1994 Oct, 16(10), 844 - 8 A new process for the production of clinical dextran by mixed-culture fermentation of Lipomyces starkeyi and Leuconostoc mesenteroides; Kim D et al.; A mixed-culture fermentation system was designed for the production of size-limited dextrans . This process was simpler and more economical than traditional methods . It required the establishment of microbial consortia of Lipomyces starkeyi ATCC 74054 and Leuconostoc mesenteroides ATCC 10830 . Controlling initial conditions, growth, and enzyme production by both organisms controlled the product size . In this process, both strains were grown separately and then mixed . Dextran fermentation was then allowed to proceed . At the desired time (and molecular size), the fermentation was harvested . The optimum pH and temperature for production of clinical dextran (75,000 MW) were 5.2 (+/- 0.1) and 28 (+/- 0.5) degrees C, respectively . Varying the ratio of L . mesenteroides to L . starkeyi in the inoculum did not significantly affect either the final cell ratios or dextran production. J Appl Bacteriol, 1994 Sep, 77(3), 271 - 80 Inter-strain relationships among wine leuconostocs and their divergence from other Leuconostoc species, as revealed by low frequency restriction fragment analysis of genomic DNA; Tenreiro R et al.; Thirty Leuconostoc oenos strains, representing 28 different isolates, were distributed into 20 genomic groups according to PFGE patterns of restriction digests . The 8 bp-specific enzymes Sfi I, Not I and Asc I cleaved the Leuc . oenos DNA in a mean of 17, 11 and four fragments respectively and Sma I produced more than 50 fragments per genome . The strain differentiating capacity of the four enzymes was similar; only two related genomic groups failed to be distinguished by Asc I or Not I . Genomic relationships between Leuc . oenos strains were quantified by numerical analysis of Not I and Sfi I banding patterns . More than half of the strains, including the starters ML34 and PSU-1, formed a major cluster . The average size of the Leuc . oenos genome was estimated as 1.86 Mb . Although similar values were obtained for the genomes of Leuc . mesenteroides, Leuc . pseudomesenteroides, Leuc . gelidum and Leuc . citreum, a significant divergence between wine and non-wine species was inferred from comparisons of genome cleavage frequencies, determined with five different enzymes. Kansenshogaku Zasshi, 1994 Sep, 68(9), 1084 - 92 {Microbiological and clinical studies of vancomycin resistant Leuconostoc spp . and Pediococcus spp . isolated from septicemia patients}; Kikuchi K et al.; We described three septicemia cases in which blood cultures yielded gram-positive cocci identified as Leuconostoc spp . and Pediococcus spp . Patients were three male adults aged 63 to 71 years with severe underlying diseases, pancreatic cancer, esophageal cancer and diabetes mellitus with chronic renal failure . They had fever and chills at the onsets of septicemia with acute obstructive suppurative cholangitis, acute pneumonia, and infection complicated with invasion sites of esophageal cancer contagious to bronchus and subcutaneous tissue . Blood cultures yielded catalase and oxidase negative highly vancomycin-resistant (MIC: 1024 micrograms/ml <) gram-positive cocci showing alpha or gamma hemolysis on blood agar plates . Two cases were polymicrobial infections . In one case with esophageal cancer, clinical symptoms persisted after the start of antimicrobial chemotherapy and the patient died 10 days later associated with complications of esophageal cancer . Leuconostoc lactis, Leuconostoc mesenteroides subsp . dextranicum, and Pediococcus acidilactici wee identified by physiological reactions . These strains were also highly resistant to teicoplanin and fosfomycin, and tolerant to all rested beta-lactams such as benzylpenicillin . This is the first report in Japan to our knowledge on the identification of Leuconostoc spp . and Pediococcus spp . isolated from human infectious diseases. J Dairy Sci, 1994 Sep, 77(9), 2718 - 24 Bacteriocins produced by Leuconostoc species; Stiles ME; Leuconostoc spp . are lactic acid bacteria that are commonly associated with foods and that are used as starter bacteria in some dairy fermentations . Lactic acid bacteria are inhibitory to other bacteria because of pH, organic acids, hydrogen peroxide, and other chemicals produced during their growth, including bacteriocins . Bacteriocin production by Leuconostoc spp . was first observed in the 1950s, but only since 1984, when antagonistic activity of Leuconostoc spp . was reported, have more extensive studies of bacteriocins produced by Leuconostoc spp . been conducted, including mesentericin Y105, produced by Leuconostoc mesenteroides spp . mesenteroides; leucocin A-UAL 187, produced by Leuconostoc gelidum; carnosin 44A, produced by Leuconostoc carnosum; and leuconocin S, produced by Leuconostoc paramesenteroides . Bacteriocins produced by leuconostocs may or may not be active against other lactic acid bacteria, but all include Listeria in their activity spectra . Mesentericin Y105 is reported to be exclusively active against Listeria spp . The amino acid sequences for leucocin A and mesentericin Y105 have been determined . Despite considerable differences in antibacterial spectra, only two amino acids differ between these bacteriocins . The prevalence of leuconostocs in many adventitious fermentations of food and the use of leuconostocs as starter bacteria in controlled fermentations make the bacteriocins produced by these bacteria of interest as possible food preservatives by addition of the bacteriocin or its producer organism to foods. Lett Appl Microbiol, 1994 Sep, 19(3), 165 - 8 Identification of Carnobacterium spp . and Leuconostoc spp . in meat by genus-specific 16S rRNA probes; Nissen H et al.; Oligonucleotide probes specific for Carnobacterium and Leuconostoc species were constructed from the variable regions of 16S rRNA obtained from the literature and sequence data bases . The probes were hybridized with crude nucleic acid extract from 32 type strains of lactic acid bacteria (LAB) commonly found on meat . Two of the probes hybridized only to the four Carnobacterium species whereas the other two hybridized only to five of the six Leuconostoc species tested . The probes were also hybridized with nucleic acids from unknown strains of LAB . The identification was consistent with the results of biochemical tests used to characterize the two genera. J Biol Chem, 1994 Aug 26, 269(34), 21639 - 43 Modification of glucose-6-phosphate dehydrogenase by 4-hydroxy-2-nonenal . Formation of cross-linked protein that inhibits the multicatalytic protease; Friguet B et al.; Incubation of glucose-6-phosphate dehydrogenase (Glu-6-PDH) from Leuconostoc mesenteroides with the lipid peroxidation product 4-hydroxy-2-nonenal leads to the formation of cross-linked protein . This is accompanied by the appearance of protein-associated fluorescence with excitation and emission maxima of 340 and 415 nm, respectively, and with the disappearance of histidine and lysine residues . Cross-linked protein is less susceptible than native Glu-6-PDH to proteolysis by the multicatalytic protease, a multienzymic proteolytic complex involved in the intracellular degradation of damaged proteins . In addition, 4-hydroxy-2-nonenal-modified Glu-6-PDH inhibits the multicatalytic protease and can therefore prevent the efficient degradation of oxidized protein . These findings may have important implications for the accumulation of altered protein and fluorescent material in vivo, processes that are believed to be involved in age- and disease-related impairment of cellular function. J Bacteriol, 1994 Aug, 176(16), 4899 - 905 Uniport of anionic citrate and proton consumption in citrate metabolism generates a proton motive force in Leuconostoc oenos; Ramos A et al.; The mechanism and energetics of citrate transport in Leuconostoc oenos were investigated . Resting cells of L . oenos generate both a membrane potential (delta psi) and a pH gradient (delta pH) upon addition of citrate . After a lag time, the internal alkalinization is followed by a continuous alkalinization of the external medium, demonstrating the involvement of proton-consuming reactions in the metabolic breakdown of citrate . Membrane vesicles of L . oenos were prepared and fused to liposomes containing cytochrome c oxidase to study the mechanism of citrate transport . Citrate uptake in the hybrid membranes is inhibited by a membrane potential of physiological polarity, inside negative, and driven by an inverted membrane potential, inside positive . A pH gradient, inside alkaline, leads to the accumulation of citrate inside the membrane vesicles . Kinetic analysis of delta pH-driven citrate uptake over a range of external pHs suggests that the monovalent anionic species (H2cit-) is the transported particle . Together, the data show that the transport of citrate is an electrogenic process in which H2cit- is translocated across the membrane via a uniport mechanism . Homologous exchange (citrate/citrate) was observed, but no evidence for a heterologous antiport mechanism involving products of citrate metabolism (e.g., acetate and pyruvate) was found . It is concluded that the generation of metabolic energy by citrate utilization in L . oenos is a direct consequence of the uptake of the negatively charged citrate anion, yielding a membrane potential, and from H(+)-consuming reactions involved in subsequent citrate metabolism, yielding a pH gradient . The uptake of citrate is driven by its own concentration gradient, which is maintained by efficient metabolic breakdown (metabolic pull). Enzyme Microb Technol, 1994 Aug, 16(8), 659 - 64 Production and selection of mutants of Leuconostoc mesenteroides constitutive for glucansucrases; Kim D et al.; After chemical mutagenesis using ethyl methane sulfonate, we isolated mutants constitutive for glucansucrases from Leuconostoc mesenteroides NRRL B-512FM, B-1142, and B-1355 . Those mutants produced glucansucrases when grown on D-glucose as well as on sucrose . They produced higher glucansucrase activities (3 to 22 times) when grown on D-glucose than the parent strains grown on sucrose . Glucansucrases from mutants B-1355C and B-1142C grown on glucose formed glucans that were highly resistant to Penicillium dextranase hydrolysis . Mutant B-512FMC dextransucrase formed the same kind of dextran as the parent strain; however, it showed higher thermal stability, even when dextran was absent. Arch Biochem Biophys, 1994 May 15, 311(1), 168 - 73 Susceptibility of glucose-6-phosphate dehydrogenase modified by 4-hydroxy-2-nonenal and metal-catalyzed oxidation to proteolysis by the multicatalytic protease; Friguet B et al.; Glucose-6-phosphate dehydrogenase from Leuconostoc mesenteroides is inactivated when exposed to metal-catalyzed oxidation or when modified by the lipid peroxidation product, 4-hydroxy-2-nonenal (HNE) . Although in each case inactivation appears to be the result of the selective modification of an active site lysine residue, only the oxidized enzyme becomes more susceptible to proteolysis by purified rat liver multicatalytic protease, a multienzymatic proteolytic complex involved in the intracellular degradation of damaged proteins . The HNE-treated enzyme remains as resistant to proteolysis by the multicatalytic protease as the native enzyme . In contrast to the HNE-treated Glu-6-PDH, enzyme modified by Fe2+ and citrate is more thermolabile and exhibits increased binding of the hydrophobic probe 8-anilino-1-naphthalene sulfonic acid (ANSA) . Heat inactivation is characterized, in part, by dissociation of the dimer to inactive subunits . No change in the secondary structure and only small variations in the fluorescence and circular dichroism of the aromatic residues are observed for the two modified forms of the enzyme as compared with the native enzyme . The increased heat sensitivity, ANSA binding, and proteolytic susceptibility are likely related to a decrease in the structural stability of oxidatively modified Glu-6-PDH . Conversely, modification of Glu-6-PDH with HNE has no apparent effect on its structural stability or proteolytic susceptibility . This finding may have important implications for the accumulation of altered protein in vivo, a process that is believed to be involved in age- and disease-related impairment of cellular function. Plasmid, 1994 May, 31(3), 251 - 64 Isolation and characterization of IS1181, an insertion sequence from Staphylococcus aureus; Derbise A et al.; The repeated nucleotide sequence isolated from a methicillin-resistant Staphylococcus aureus isolate displays the characteristic features of an insertion sequence and was named IS1181 . It has a size of 1512 bp and consists of a 1359-bp open reading frame that encodes a 439-amino-acid protein which is predicted to be highly basic and 23-bp terminal inverted complementary repeated sequences exhibiting six mismatches . The three copies of IS1181 isolated from distinct parts of the chromosome of S . aureus, BM3121, are flanked at their ends by 8-bp direct repeats, suggesting a duplication of the target sequence . IS1181 exhibits similarities with IS1165 from Leuconostoc mesenteroides and IS1001 from Bordetella parapertusis . IS1181 was detected in at least two to eight copies in 41 of the 52 S . aureus isolates tested, whereas none of the 26 coagulase-negative staphylococci, 24 streptococci, or 11 enterococci analyzed carried nucleotide sequences hybridizing with IS1181. Appl Environ Microbiol, 1994 May, 60(5), 1459 - 66 Growth and energetics of Leuconostoc oenos during cometabolism of glucose with citrate or fructose; Salou P et al.; The metabolic and energetic characterization of the growth of Leuconostoc oenos on glucose-citrate or glucose-fructose mixtures enables the potential role of this bacterium in the wine-making process to be ascertained . Moreover, mixotrophic conditions remain a suitable means for improving biomass productivities of malolactic starter cultures . When the malolactic bacterium L . oenos was grown in batch cultures on complex medium at pH 5.0 with glucose-citrate or glucose-fructose mixtures, enhancement of both the specific growth rate and biomass production yields was observed . While growth was possible on fructose as the sole source of energy, citrate alone did not allow subsequent biomass production . The metabolic interactions between the catabolic pathways of the glucose cosubstrates and the heterofermentation of hexoses led to an increased acetate yield as a result of modified NADH oxidation . However, the calculated global coenzyme regeneration showed that the reducing equivalent balance was never equilibrated . The stimulatory effects of these glucose cosubstrates on growth resulted from increased ATP synthesis by substrate-level phosphorylation via acetate kinase . While the energetic efficiency remained close to 10 g of biomass produced per mol of ATP, the increase in the specific growth rate and biomass production yields was directly related to the rate and yield of ATP generation. J Appl Bacteriol, 1994 Feb, 76(2), 135 - 41 Antimicrobial activity of shredded carrot extracts on food-borne bacteria and yeast; Babic I et al.; Purified ethanolic extracts of peeled and shredded carrots showed an antimicrobial effect against a range of food-borne micro-organisms . The minimum inhibitory concentration, expressed as mg ml-1 dried carrot material used for the extraction were: Leuconostoc mesenteroides, 27; Listeria monocytogenes, > 27 < 55; Staphylococcus aureus, > 27 < 55; Pseudomonas fluorescens, > 55 < 110; Candida lambica, > 55 < 110; Escherichia coli, > 110 < 220 . The antimicrobial activity was not linked to phenolic compounds but was presumably due to apolar components . Free saturated fatty acid (dodecanoic acid) and methyl esters of saturated fatty acids (of dodecanoic and pentadecanoic acids) were identified in purified active extracts of carrots by gas chromatography coupled to mass spectrometry and could be responsible for the antimicrobial activity . This effect did not seem to play a role in the resistance of shredded carrots to microbial spoilage, although the antimicrobial activity was present in fresh carrots at concentrations sufficient to inhibit spoilage bacteria. Appl Biochem Biotechnol, 1994 Feb, 44(2), 101 - 17 Production and use of glucosyltransferases from Leuconostoc mesenteroides NRRL B-1299 for the synthesis of oligosaccharides containing alpha-(1-->2) linkages; Remaud-Simeon M et al.; Glucosyltransferase activities, produced by batch culture of Leuconostoc mesenteroides NRRL B-1299, were recovered both in the culture supernatant (SGT) and associated with the insoluble part of the culture (IGT) . A total glucosyltransferase activity of 3.5 U/mL was measured in batch culture . The enzymes from the supernatant were purified 313 times using aqueous two-phase partition between dextran and PEG phases, yielding a preparation with 18.8 U/mg protein . It was shown that both SGT and IGT preparations catalyze acceptor reactions and transfer the glucose unit from sucrose onto maltose to produce glucooligosaccharides . Some of the glucooligosaccharides synthesized (Ln series) contain alpha-(1-->6) osidic linkages and a maltose residue at the reducing end . They were completely hydrolyzed by glucoamylase and dextranase . The other glucooligosaccharides synthesized (Bn series) resisted the action of these enzymes . The tetrasaccharide of this series has been characterized by 13C NMR . Its structure was determined as 2-O-alpha-D-glucosylpanose . The oligosaccharides synthesized by the maltose acceptor reaction with the SGT and IGT preparations only differed in the relative amounts in which they were produced . The difference may arise from diffusional limitations appearing when the insoluble catalyst is used . Under the assay conditions, the glucanase resistant oligosaccharide yield was 35% with both glucosyltransferase preparations. Arch Biochem Biophys, 1994 Feb 1, 308(2), 471 - 6 Determination of the number of sucrose and acceptor binding sites for Leuconostoc mesenteroides B-512FM dextransucrase, and the confirmation of the two-site mechanism for dextran synthesis; Su D et al.; In previous studies on dextransucrase using pulse and chase experiments with {14C}sucrose, Robyt et al . {Arch . Biochem . Biophys . 165 (1974) 634-640} proposed a two-site insertion mechanism to explain the data for the synthesis of dextran . To further establish the validity of the two-site mechanism, the number of sucrose binding sites at the active site have been determined by using equilibrium dialysis with 6-deoxysucrose, a strong competitive inhibitor for dextransucrase . A ligand binding plot gave a straight line that indicated there were two sucrose binding sites at the active site . A similar experiment was performed using the acceptor, maltose . The ligand binding plot for maltose also gave a straight line and indicated that there was one acceptor binding site at the active site . These results corroborate the proposed two-site mechanism for dextran synthesis . To further test the two-site mechanism, dextransucrase was partially inactivated to varying extents by reaction with diethylpyrocarbonate, which chemically modifies essential active-site histidines . The various partially inactivated enzymes were assayed for dextran synthesis and for the synthesis of maltose acceptor products . A plot of the log of the relative percentage of dextran synthesized and acceptor products synthesized against varying degrees of enzyme inactivation showed that the synthesis of dextran decreased to a greater extent than did the decrease of the synthesis of acceptor product . The proposed mechanism requires two sucrose sites for the synthesis of dextran and only one sucrose site for the synthesis of acceptor product . When one site is modified, the synthesis of dextran stops, but the synthesis of acceptor products can continue at the other site . Thus, the greater loss of dextran synthesis in comparison with the lesser loss of acceptor product synthesis by enzymes modified to varying degrees, gives further evidence for the two-site mechanism for dextran synthesis. J Basic Microbiol, 1994, 34(3), 173 - 82 Antibacterial activity of three Leuconostoc strains isolated from vacuum-packaged processed meats; Papathanasopoulos MA et al.; One hundred and fifty lactic acid bacteria (LAB) isolated from vacuum-packaged processed meats were screened for antagonistic activity against various food spoilage microorganisms and foodborne pathogens . Nineteen strains produced bacteriocins active against closely related LAB and Listeria strains . Leuconostoc carnosum (LA54a and TA26b) and Leuconostoc mesenteroides subspecies dextranicum (TA33a) produced bacteriocins that were susceptible to proteolytic enzymes, but not to catalase, lysozyme or chloroform . They were heat stable up to 100 degrees C for thirty minutes at pH 2 to 7, and exerted a bacteriolytic effect . Bacteriocin production by all Leuconostoc strains was growth associated, occurring at incubation temperatures of 0 degrees C to 30 degrees C and initial medium pH 4.5 to 7.5 . Probing of plasmid DNA from the three Leuconostoc strains with an oligonucleotide probe homologous to the nucleotide sequence of leucocin A-UAL 187 indicated plasmid-mediated bacteriocin production . Homology of the three Leuconostoc bacteriocin-coding genes to the amino-terminal end of the leucocin A-UAL 187 gene from Leuconostoc gelidum UAL 187 is therefore suggested . This evidence implies that all three Leuconostoc strains produce type 2, Listeria active bacteriocins. Biochemistry, 1993 Dec 14, 32(49), 13696 - 702 An active-site peptide containing the second essential carboxyl group of dextransucrase from Leuconostoc mesenteroides by chemical modifications; Funane K et al.; The treatment of Leuconostoc mesenteroides B-512F dextransucrase with 10 mM 1-ethyl-3-{3-(dimethylamino)propyl}carbodiimide (EDC) and glycine ethyl ester (GEE) inactivated the enzyme almost completely within 24 min where the modification of one carboxyl group/mol of the enzyme by EDC was attained . Though 30 mM diethyl pyrocarbonate (DEP) also inactivated the enzyme, about 35% of the activity remained during a 36-min incubation . When 10 mol of imidazole residues/mol of the enzyme was modified by DEP, 50% of the activity was still retained . The addition of the substrate sucrose greatly retarded the enzyme inactivation by EDC . However, the addition of dextran slightly protected the inactivation of the glucosyl-transferring activity and accelerated the inactivation of the sucrose-cleaving activity . In the case of DEP, the addition of sucrose or dextran gave no influence on the inactivation of the enzyme . Therefore, the carboxyl group seemed to play a more important role in the substrate binding and in the catalytic activity of the dextransucrase than the imidazolium group . Differential labeling of Leuconostoc dextransucrase by EDC was conducted in the presence of a sucrose analog, sucrose monocaprate . The fluorescent probe N-(1-naphthyl)ethylenediamine (EDAN) was used as the nucleophile instead of GEE . A fluorescent labeled peptide was isolated from a trypsin digest of the EDC-EDAN modified enzyme . The amino acid sequence of the isolated peptide was Leu-Gln-Glu-Asp-Asn-Ser-Asn-Val-Val-Val-Glu-Ala.(ABSTRACT TRUNCATED AT 250 WORDS) J Appl Bacteriol, 1993 Dec, 75(6), 595 - 603 Taxonomic studies on some leuconostoc-like organisms from fermented sausages: description of a new genus Weissella for the Leuconostoc paramesenteroides group of species; Collins MD et al.; Taxonomic studies were performed on some unknown Leuconostoc-like organisms from fermented Greek sausage . Comparative 16S rRNA sequence analysis showed the unidentified organisms represent a new line within the Leuconostoc paramesenteroides group of species . On the basis of the results of this and earlier phylogenetic investigations, it is proposed that Leuconostoc paramesenteroides and related species be reclassified in a new genus Weissella . In addition a new species, Weissella hellenica, is proposed for the isolates from fermented sausage. Plasmid, 1993 Nov, 30(3), 212 - 23 Sequence analysis of Leuconostoc oenos DNA: organization of pLo13, a cryptic plasmid; Fremaux C et al.; A Leuconostoc oenos plasmid, pLo13, was studied to analyze its genetic organization and to define its functions . The nucleotide sequence (3948 bp) revealed three major open reading frames . Features commonly found in plasmids that replicate via a rolling-circle mechanism were identified within pLo13: first, a sequence coding for a protein with an amino acid sequence homologous to the plasmid recombination enzymes (Pre), but for which a specific target site similar to those previously described was not found; second, a sequence probably encoding a replication protein (Rep) . The putative pLo13 Rep protein amino acid sequence is divergent from the pC194-pUB110 family Rep proteins . However, the consensus sequence of the Rep protein active site was found, as well as the Rep protein consensus target site . No sequence similar to the previously described minus-origins (SSOs) are present in pLo13; nevertheless, a 200-bp sequence rich in imperfect palindromes may be involved in the minus-strand replication . These overall differences are in agreement with the previously reported important phylogenetic distance existing between Ln . oenos and other lactic acid bacteria. J Biol Chem, 1993 Oct 15, 268(29), 21632 - 6 Thermal switching between enhanced and arrested reactivation of bacterial glucose-6-phosphate dehydrogenase assisted by GroEL in the absence of ATP; Hansen JE et al.; Facilitation of protein folding by GroEL usually requires involvement of GroES and ATP . In their absence nascent proteins tend to be arrested on GroEL or, if released, fail to show enhancement of reactivation yield relative to that observed without the chaperonin . In contrast, the yield of reactivation of glucose-6-phosphate dehydrogenase (Glu-6-PDH) from Leuconostoc mesenteroides at 20 degrees C is increased 2-3-fold (to over 80%) by GroEL alone . ATP greatly enhances the rate of GroEL-assisted reactivation and slightly increases its yield to 90% . The efficiency of the GroEL-assisted reactivation of Glu-6-PDH is strongly dependent on temperature . A switch from enhanced to fully arrested reactivation occurs over a narrow temperature range from 25 to 30 degrees C in the presence of GroEL when ATP is absent . At physiological temperature therefore, reactivation is fully arrested by GroEL if ATP is absent and in its presence the protein is released in a form not committed to correct folding . The data shows that the committing step in Glu-6-PDH refolding occurs while the nascent protein is bound to GroEL, a step which is temperature-sensitive . The extreme temperature sensitivity of this step indicates a sharp structural transition in GroEL. Carbohydr Res, 1993 Oct 4, 248, 339 - 48 Control of the synthesis of dextran and acceptor-products by Leuconostoc mesenteroides B-512FM dextransucrase; Su D et al.; In the maltose-acceptor reaction of Leuconostoc mesenteroides B-512FM dextransucrase, some of the D-glucose moieties of sucrose are diverted from the synthesis of dextran and are transferred to the nonreducing end of maltose to form panose . Glucose is also transferred to panose and to subsequent acceptor products to give a homologous series of isomaltosyl dextrins attached alpha-(1-->6) to maltose . Three experimental parameters were studied to obtain quantitative information about the yield and distribution of acceptor products and the yield of dextran: (a) the ratio of maltose to sucrose, (b) the concentration of maltose and sucrose, and (c) the amount of enzyme . The reactions were run with {14C}sucrose and the amount of each acceptor product and the amount of dextran synthesized were determined for (a), (b), and (c) by TLC separation and measurement of the radioactivity with a PhosphorImager . It was found that an increase in the ratio of maltose to sucrose increased the amount of acceptor products with a concomitant decrease in the synthesis of dextran . Further, as the ratio was increased, the number of acceptor-products decreased . When the concentrations of maltose and sucrose were increased and the ratio was maintained at 1:1, there also was a decrease in the amount of dextran and an increase in the amount of acceptor-products . In addition, there was a decrease in the amount of dextran and an increase in the amount and number of acceptor-products when the amount of enzyme was increased . The first acceptor-product can be exclusively obtained without the formation of any dextran, by using a specific ratio and concentration of maltose and sucrose and a specified amount of enzyme. Zhonghua Min Guo Wei Sheng Wu Ji Mian Yi Xue Za Zhi, 1993 Aug, 26(3), 116 - 31 Antimicrobial activity of sulfur dioxide to certain lactic acid bacteria isolated from wines; Fang TJ et al.; This study was conducted to investigate the relationship between pH and the toxicity of sulfur dioxide against homo- and hetero-lactic acid bacteria isolated from American acidic wines . Malolactic fermentation was found to be growth-associated in homo- and hetero-lactic strains . The pH of CBB broth had an insignificant effect on the specific death rate of these strains; the concentration of molecular sulfur dioxide had a great effect on the specific death rate and malate degradation . Laboratory or freshly isolated strains were exposed to various concentrations of free sulfur dioxide at pH 3.8 and 3.4 . At pH 3.4, sulfur dioxide was more effective against lactic acid bacteria than at pH 3.8 since more was present as molecular sulfur dioxide and causing an increase in the specific death rate . Pediococcus strain BB was more resistant to sulfur dioxide than those hetero-lactic fermentation strains such as Leuconostoc oenos PSU-1 and ML-34 . The effect of sulfur dioxide concentration on the viability of L . oenes ML-34, PSU-1, and Pediococcus strain BB appeared to be biphasic . No or little L-malic acid was degraded when the homo- and hetero-fermentative strains were killed by sulfur dioxide. J Bacteriol, 1993 Jul, 175(13), 3941 - 8 Pathway and regulation of erythritol formation in Leuconostoc oenos; Veiga-da-Cunha M et al.; It was recently observed that Leuconostoc oenos GM, a wine lactic acid bacterium, produced erythritol anaerobically from glucose but not from fructose or ribose and that this production was almost absent in the presence of O2 . In this study, the pathway of formation of erythritol from glucose in L . oenos was shown to involve the isomerization of glucose 6-phosphate to fructose 6-phosphate by a phosphoglucose isomerase, the cleavage of fructose 6-phosphate by a phosphoketolase, the reduction of erythrose 4-phosphate by an erythritol 4-phosphate dehydrogenase and, finally, the hydrolysis of erythritol 4-phosphate to erythritol by a phosphatase . Fructose 6-phosphate phosphoketolase was copurified with xylulose 5-phosphate phosphoketolase, and the activity of the latter was competitively inhibited by fructose 6-phosphate, with a Ki of 26 mM, corresponding to the Km of fructose 6-phosphate phosphoketolase (22 mM) . These results suggest that the two phosphoketolase activities are borne by a single enzyme . Extracts of L . oenos were also found to contain NAD(P)H oxidase, which must be largely responsible for the reoxidation of NADPH and NADH in cells incubated in the presence of O2 . In cells incubated with glucose, the concentrations of glucose 6-phosphate and of fructose 6-phosphate were higher in the absence of O2 than in its presence, explaining the stimulation by anaerobiosis of erythritol production . The increase in the hexose 6-phosphate concentration is presumably the result of a functional inhibition of glucose 6-phosphate dehydrogenase because of a reduction in the availability of NADP. Appl Microbiol Biotechnol, 1993 Jul, 39(4-5), 547 - 52 Recognition of Leuconostoc oenos strains by the use of DNA restriction profiles; Lamoureux M et al.; The chromosome of 41 Leuconostoc oenos strains obtained from collections in different countries was analysed with the aim of differentiating the strains . Pulsed field electrophoresis (TAFE) was used to separate large DNA fragments created by the restriction enzymes NotI, SfiI and ApaI, which specifically recognize guanines or cytosines . The genomic DNA of 11 strains was analysed initially with NotI and only four different restriction profiles were observed . The genome size ranged from 1.8 to 2.1 megabase pairs (Mbp) . Constant field electrophoresis applied to DNA treatment with 19 different restriction enzymes showed that the size of the fragments obtained increased proportionally to the percentage G + C present at the site of restriction . EcoRI and HindIII profiles revealed that the zone between 9 and 23 kbp allowed differentiation of the strains tested . Thus, the 41 strains fell into 30 restriction groups using only two enzymes . Hybridization with a non-radioactive DNA probe coding for 16S rRNA revealed that there were two 16S genes on the chromosome. J Clin Microbiol, 1993 May, 31(5), 1030 - 3 Identification of Leuconostoc spp . by analysis of soluble whole-cell protein patterns; Elliott JA et al.; Leuconostoc spp . share several physiologic characteristics, which sometimes makes it difficult to identify these organisms to the species level . We developed a system, based on the patterns of soluble whole-cell proteins separated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis, that was able to discriminate between the six Leuconostoc spp . that are capable of growth at 37 degrees C . Nine unidentified Leuconostoc-like bacterial isolates that were included in the study did not fit any of the protein profiles of the type strains and may represent new Leuconostoc spp. J Bacteriol, 1993 May, 175(10), 3232 - 5 Membrane permeabilization of Listeria monocytogenes and mitochondria by the bacteriocin mesentericin Y105; Maftah A et al.; Mesentericin Y105, a bacteriocin produced by a Leuconostoc mesenteroides strain, dissipates the plasma membrane potential of Listeria monocytogenes and inhibits the transport of leucine and glutamic acid . It also induces an efflux of preaccumulated amino acids from cells . In addition, the bacteriocin uncouples mitochondria by increasing state 4 respiration and decreasing state 3 respiration . The bacteriocin inhibits ATP synthase and adenine nucleotide translocase of the organelle while the affinity of ADP for its carrier is not modified . The results suggest that mesentericin Y105 acts by inducing, directly or indirectly, pore formation in the energy-transducing membranes, especially those of its natural target. Biochim Biophys Acta, 1993 Apr 21, 1163(1), 89 - 96 Renaturation of glucose-6-phosphate dehydrogenase from Leuconostoc mesenteroides after denaturation in 4 M guanidine hydrochloride: kinetics of aggregation and reactivation; Plomer JJ et al.; In 4 M guanidine hydrochloride (GdnHCl), the dimeric enzyme glucose-6-phosphate dehydrogenase from Leuconostoc mesenteroides (G6PD) dissociated to subunits and was extensively unfolded . Rapid dilution of this high GdnHCl concentration allowed G6PD to partially renature, as measured by enzyme reactivation, to a level which depended on the conditions employed . The fraction of the enzyme which did not renature aggregated and precipitated out of solution, a process which could not be substantially prevented by stabilizing additives . Based on the enzyme concentration dependence of the reactivation yield and on a comparison of the aggregation and reactivation rates, it was determined that aggregation and reactivation compete kinetically for a partially-folded intermediate only very early in the process, during the rapid GdnHCl-dilution step . The kinetics of G6PD reactivation were sigmoidal, indicating that this process involves more than one rate-limiting reaction . The kinetics depended on enzyme concentration in a higher than first-order manner, indicating that association of subunits is one of the rate-limiting reactions . A renaturation mechanism compatible with these observations is described, which involves a bi-unimolecular (subunit association-folding) reaction sequence, with rate constants equal to 2.19 microM-1 min-1 and 0.140 min-1, respectively . This mechanism involves an inactive, dimeric, G6PD-folding intermediate, a species whose existence has recently been established by equilibrium denaturation experiments (Plomer, J.J . and Gafni, A . (1992) Biochim . Biophys . Acta 1122, 234-242). Arch Biochem Biophys, 1993 Mar, 301(2), 391 - 5 Oxidative modification of glucose-6-phosphate dehydrogenase from Leuconostoc mesenteroides by an iron(II)-citrate complex; Szweda LI et al.; Incubation of glucose-6-phosphate dehydrogenase from Leuconostoc mesenteroides with Fe2+ and citrate results in rapid O2-dependent inactivation of the enzyme . Maximal rate of inactivation occurred at equimolar concentrations of Fe2+ and citrate . Loss of enzyme activity appears to be the result of selective oxidative modification, as evidenced by a corresponding increase in protein carbonyl content . Partially inactivated enzyme remained predominantly in the dimeric form with no change in the apparent affinity of the remaining active subunits for substrate . Modified Glu-6-PDH was, however, more susceptible to heat denaturation . Our results suggest that the Fe(2+)-citrate complex binds to the glucose 6-phosphate binding site and then undergoes reaction with H2O2 formed in solution leading to the oxidative modification of amino acids essential for enzyme activity. J Biol Chem, 1993 Feb 15, 268(5), 3342 - 7 Inactivation of glucose-6-phosphate dehydrogenase by 4-hydroxy-2-nonenal . Selective modification of an active-site lysine; Szweda LI et al.; Incubation of glucose-6-phosphate dehydrogenase from Leuconostoc mesenteroides with 4-hydroxy-2-nonenal (HNE) results in a pseudo first-order loss of enzyme activity . The pH dependence of the inactivation rate exhibits an inflection around pH 10, and the enzyme is protected from inactivation by glucose 6-phosphate . Loss of enzyme activity corresponds with the formation of one carbonyl function per enzyme subunit and the appearance of a lysine-HNE adduct . The data presented in this paper are consistent with the view that the epsilon-amino group of a lysine residue in the glucose 6-phosphate-binding site reacts with the double bond (C3) of HNE, resulting in the formation of a stable secondary amine derivative and loss of enzyme activity . We have described a mechanism by which HNE may, in part, mediate free radical damage . In addition, a method for the detection of the lysine-HNE adduct is introduced. Appl Environ Microbiol, 1993 Feb, 59(2), 607 - 9 Development and use of a selective medium for isolation of Leuconostoc spp . from vegetables and dairy products; Benkerroum N et al.; A selective medium (LUSM medium) for the isolation of Leuconostoc spp . was developed . This medium contained 1.0% glucose, 1.0% Bacto Peptone (Difco), 0.5% yeast extract (BBL), 0.5% meat extract (Difco), 0.25% gelatin (Difco), 0.5% calcium lactate, 0.05% sorbic acid, 75 ppm of sodium azide (Sigma), 0.25% sodium acetate, 0.1% (vol/vol) Tween 80, 15% tomato juice, 30 micrograms of vancomycin (Sigma) per ml, 0.20 microgram of tetracycline (Serva) per ml, 0.5 mg of cysteine hydrochloride per ml, and 1.5% agar (Difco) . LUSM medium was used successfully for isolation and enumeration of Leuconostoc spp . in dairy products and vegetables . Of 116 colony isolates obtained from fresh raw milk, curdled milk, or various vegetables, 115 were identified as members of the genus Leuconostoc . A total of 89 of these isolates were identified to species; 13.5% of the isolates were Leuconostoc cremoris, 7.9% were Leuconostoc mesenteroides subsp . mesenteroides, 11.2% were Leuconostoc mesenteroides subsp . dextranicum, 16.9% were Leuconostoc mesenteroides subsp . paramesenteroides, 10.1% were leuconostoc lactis, and 40.4% were Leuconostoc oenos . When we compared the counts obtained for two Leuconostoc strains, Leuconostoc dextranicum 181 and L . cremoris JLL8, on MRS agar and LUSM medium, we found no significant difference between the values obtained on the two media. Z Lebensm Unters Forsch, 1993 Jan, 196(1), 45 - 8 Determination of optimum pH and temperature for pasteurization of citrus juices by response surface methodology; Ulgen N et al.; Optimization of microbial death, enzyme inactivation and vitamin C retention during pasteurization of pH-adjusted orange juice is discussed free of equipment-dependent parameters such as the heating lag . The pH-temperature optimum was determined by response surface methodology in the range of 65 degrees C-75 degrees C and pH 2.5-4.0 . The results implied that there was no pectinesterase activity below pH 3.5 . Leuconostoc mesenteroides had its maximum and minimum thermal resistance at pH 3.5 and pH 2.7, respectively . For an ideal theoretical process requiring four log cycles of microbial reduction the optimum pasteurization conditions were 12 min at 75 degrees C and pH 2.7. J Gen Microbiol, 1992 Dec, 138 ( Pt 12), 2725 - 31 Characterization and purification of mesentericin Y105, an anti-Listeria bacteriocin from Leuconostoc mesenteroides; Hechard Y et al.; A Leuconostoc mesenteroides ssp . mesenteroides was isolated from goat's milk on the basis of its ability to inhibit the growth of Listeria monocytogenes . The antimicrobial effect was due to the presence in the culture medium of a compound, named mesentericin Y105, excreted by the Leuconostoc mesenteroides Y105 . The compound displayed known features of bacteriocins from lactic acid bacteria . It appeared as a proteinaceous molecule exhibiting a narrow inhibitory spectrum limited to genus Listeria . The apparent relative molecular mass, as indicated by activity detection after SDS-PAGE, was 2.5-3.0 kDa . The bacteriocin was purified to homogeneity by a simple three-step procedure: a crude supernatant obtained from an early-stationary-phase culture in a defined medium was subjected to affinity chromatography on a blue agarose column, followed by ultrafiltration through a 5 kDa cut-off membrane, and finally by reverse-phase HPLC on a C4 column . Microsequencing of the pure bacteriocin and of tryptic fragments showed that mesentericin Y105 is a 36 amino acid polypeptide whose primary structure is close to that of leucocin A-UAL 187, which contains an extra residue at the C-terminus and displays only two differences in the overlapping sequence . However, unlike leucocin A-UAL 187, mesentericin Y105 displayed a bactericidal mode of action. Clin Biochem, 1992 Dec, 25(6), 457 - 62 An enzymatic method for measuring serum mannitol and its use in hemodialysis patients; Diamandis EP et al.; We evaluated two chemical methods for quantifying mannitol in serum, based on the oxidation of mannitol by periodate, and measurement of the formaldehyde formed with chromotropic acid (colorimetry) or acetylacetone (fluorometry) . We found interference in these methods by serum glycerol . Additionally, a high-performance liquid chromatography (HPLC) method was evaluated and found to be specific but impractical for routine use . We therefore, developed an enzymatic fluorometric procedure, based on the oxidation of mannitol by beta-NAD to fructose and NADH, in the presence of the enzyme mannitol dehydrogenase (MD) . MD is not commercially available and was partially purified from cultures of Leuconostoc mesenteroides . This new method is specific, sensitive, simple, and accurate and is proposed as the method of choice for measuring mannitol in the serum of patients who received this sugar alcohol during routine hemodialysis treatment. Appl Environ Microbiol, 1992 Nov, 58(11), 3784 - 6 On-line visualization of the competitive behavior of antagonistic bacteria; Hechard Y et al.; To study the interaction between cocultured Listeria monocytogenes and an antagonistic Leuconostoc strain producing an anti-Listeria bacteriocin, flow cytometry, a technique allowing on-line and real-time analysis, was used along with classical microbiological methods . Culture methods and flow cytometric measurements of the mixed culture over time point to a bactericidal action of the lactic acid-producing bacterial strain against L . monocytogenes cells. Diagn Microbiol Infect Dis, 1992 Sep-Oct, 15(7), 641 - 4 In vitro activity of mersacidin (M87-1551), an investigational peptide antibiotic tested against gram-positive bloodstream isolates; Barrett MS et al.; We measured the in vitro activity of mersacidin (formerly M87-1551) against 183 clinical isolates (vancomycin susceptible) and 12 additional vancomycin-resistant strains of Gram-positive bacteria . The activity for mersacidin increased an average twofold (range, 1.7- to 7.6-fold) in a calcium-enriched medium . The minimum inhibitory concentration (MIC)90 for mersacidin was 8-32 times higher than vancomycin for staphylococci, 4-64 times higher for enterococci, and up to 32 times higher for other organisms tested . The MIC90 for MDL 62873, a comparison compound, was less than or equal to 0.5 micrograms/ml for all species except Staphylococcus haemolyticus (MIC90, 4 micrograms/ml), and it was greater than or equal to 4-fold more active than vancomycin . Against selected vancomycin-resistant strains, mersacidin had MICs greater than or equal to 16 micrograms/ml for enterococci, 4-32 micrograms/ml for Pediococcus, and less than or equal to 2 micrograms/ml for Leuconostoc species . Mersacidin may have some clinical utility in documented infections caused by staphylococci, nonenteric streptococci, Pediococcus, and Leuconostoc. Biochim Biophys Acta, 1992 Aug 21, 1122(3), 234 - 42 Denaturation of glucose-6-phosphate dehydrogenase from Leuconostoc mesenteroides by guanidine hydrochloride; identification of inactive, partially unfolded, dimeric intermediates; Plomer JJ et al.; The denaturation of the dimeric enzyme glucose-6-phosphate dehydrogenase from Leuconostoc mesenteroides by guanidine hydrochloride has been studied using enzymatic activity, intrinsic fluorescence, circular dichroism, and light scattering measurements . Equilibrium experiments at 25 degrees C revealed that between 0.9 and 1.2 M denaturant the enzyme underwent a conformational change, exposing tryptophan residues to solvent, with some loss of secondary structure and a complete loss of enzymatic activity but without dimer dissociation to subunits . This inactive, partially unfolded, dimeric intermediate was susceptible to slow aggregation, perhaps due to exposure of 'sticky' hydrophobic stretches of the polypeptide chain . A second equilibrium transition, reflecting extensive unfolding and dimer dissociation, occurred only at denaturant concentrations above 1.4 M . Kinetics experiments demonstrated that in the denaturant concentration range of 1.7-1.9 M the fluorescence change occurred in two distinct steps . The first step involved a large, very rapid drop in fluorescence whose rate was strongly dependent on the denaturant concentration . This was followed by a small, relatively slow rise in the emission intensity, the rate of which was independent of denaturant concentration . Enzymatic activity was lost with a denaturant-concentration-dependent rate, which was approx . 3-times slower than the rate of the first step in fluorescence change . A denaturation mechanism incorporating several unfolding intermediates and which accounts for all the above results is presented and discussed . While the fully unfolded enzyme regained up to 55% of its original activity upon dilution of denaturant to a concentration that would be expected to support native enzyme, denaturation intermediates were able to reactivate only minimally and in fact were found to aggregate and precipitate out of solution. J Bacteriol, 1992 Aug, 174(16), 5302 - 8 Electrogenic malate uptake and improved growth energetics of the malolactic bacterium Leuconostoc oenos grown on glucose-malate mixtures; Loubiere P et al.; Growth of the malolactic bacterium Leuconostoc oenos was improved with respect to both the specific growth rate and the biomass yield during the fermentation of glucose-malate mixtures as compared with those in media lacking malate . Such a finding indicates that the malolactic reaction contributed to the energy budget of the bacterium, suggesting that growth is energy limited in the absence of malate . An energetic yield (YATP) of 9.5 g of biomass.mol ATP-1 was found during growth on glucose with an ATP production by substrate-level phosphorylation of 1.2 mol of ATP.mol of glucose-1 . During the period of mixed-substrate catabolism, an apparent YATP of 17.7 was observed, indicating a mixotrophy-associated ATP production of 2.2 mol of ATP.mol of glucose-1, or more correctly an energy gain of 0.28 mol of ATP.mol of malate-1, representing proton translocation flux from the cytoplasm to the exterior of 0.56 or 0.84 H+.mol of malate-1(depending on the H+/ATP stoichiometry) . The growth-stimulating effect of malate was attributed to chemiosmotic transport mechanisms rather than proton consumption by the malolactic enzyme . Lactate efflux was by electroneutral lactate -/H+ symport having a constant stoichiometry, while malate uptake was predominantly by a malate -/H+ symport, though a low-affinity malate- uniport was also implicated . The measured electrical component (delta psi) of the proton motive force was altered, passing from -30 to -60 mV because of this translocation of dissociated organic acids when malolactic fermentation occurred. J Dairy Res, 1992 Aug, 59(3), 359 - 67 Intracellular pH and the role of D-lactate dehydrogenase in the production of metabolic end products by Leuconostoc lactis; FitzGerald RJ et al.; The kinetics of lactate dehydrogenase from Leuconostoc lactis NCW1 were studied . The pH optimum for the enzyme depended on the concentration of pyruvate used in the assay and the enzyme displayed an ordered mechanism with respect to substrate binding . The Km for pyruvate and NADH and the Vmax of the enzyme decreased 20-, 30- and 6-fold respectively as the pH decreased from 8.0 to 5.0 . No activators were found and none of the intermediates of the phosphoketolase pathway tested inhibited the enzyme . ATP, ADP, GTP and NAD+ were inhibitory . The intracellular volume (Vol(in)) and intracellular pH (pH(in)) decreased as the extracellular pH (pH(ex)) decreased . Co-metabolism of citrate and glucose affected the Vol(in) but did not affect the pH(in), which decreased by 0.6 units per unit change in pH(ex); at pH 7.0, the pH(in) and pH(ex) were equal . The results suggest that pH(in) may play a role in determining the production of diacetyl and acetoin at low pH by Leuconostoc. J Bacteriol, 1992 Jul, 174(13), 4475 - 81 Leuconostoc lactis beta-galactosidase is encoded by two overlapping genes; David S et al.; A 16-kb BamHI fragment of the lactose plasmid pNZ63 from Leuconostoc lactis NZ6009 was cloned in Escherichia coli MC1061 by using pACYC184 and was found to express a functional beta-galactosidase . Deletion and complementation analysis showed that the coding region for beta-galactosidase was located on a 5.8-kb SalI-BamHI fragment . Nucleotide sequence analysis demonstrated that this fragment contained two partially overlapping genes, lacL (1,878 bp) and lacM (963 bp), that could encode proteins with calculated sizes of 72,113 and 35,389 Da, respectively . The L . lactis beta-galactosidase was overproduced in E . coli by using a lambda pL expression system . Two new proteins with M(r)s of 75,000 and 36,000 appeared upon induction of PL . The N-terminal sequences of these proteins corresponded to those deduced from the lacL and lacM gene sequences . Mutation and deletion analysis showed that lacL expression is essential for LacM production and that both the lacL and lacM genes are required for the production of a functional beta-galactosidase in E . coli . The deduced amino acid sequences of the LacL and LacM proteins showed considerable identity with the sequences of the N- and C-terminal parts, respectively, of beta-galactosidases from other lactic acid bacteria or E . coli . DNA and protein sequence alignments suggest that the L . lactis lacL and lacM genes have been generated by an internal deletion in an ancestral beta-galactosidase gene. Singapore Med J, 1992 Jun, 33(3), 241 - 3 Leuconostoc bacteraemia; Ling ML; Leuconostoc species, a gram-positive coccal bacterium that is classically moderately susceptible to ampicillin and penicillin and resistant to vancomycin is a potential pathogen in the immunocompromised host . Twenty-eight isolates were collected from patients' blood culture specimens in the year 1989-1990 . The clinical history and course of nineteen of these patients were studied . Five of them recovered without any antimicrobial therapy and in eight patients Leuconostoc species was isolated with other organisms in the blood culture specimens . The question arises as to when Leuconostoc species is of clinical significance when isolated in the blood culture specimens of patients. Protein Sci, 1992 Mar, 1(3), 329 - 34 Lysine-21 of Leuconostoc mesenteroides glucose 6-phosphate dehydrogenase participates in substrate binding through charge-charge interaction; Lee WT et al.; Leuconostoc mesenteroides glucose 6-phosphate dehydrogenase (G6PD) was isolated in high yield and purified to homogeneity from a newly constructed strain of Escherichia coli which lacks its own glucose 6-phosphate dehydrogenase gene . Lys-21 is one of two lysyl residues in the enzyme previously modified by the affinity labels pyridoxal 5'-phosphate and pyridoxal 5'-diphosphate-5'-adenosine, which are competitive inhibitors of the enzyme with respect to glucose 6-phosphate (LaDine, J.R., Carlow, D., Lee, W.T., Cross, R.L., Flynn, T.G., & Levy, H.R., 1991, J . Biol . Chem . 266, 5558-5562) . K21R and K21Q mutants of the enzyme were purified to homogeneity and characterized kinetically to determine the function of Lys-21 . Both mutant enzymes showed increased Km-values for glucose 6-phosphate compared to wild-type enzyme: 1.4-fold (NAD-linked reaction) and 2.1-fold (NADP-linked reaction) for the K21R enzyme, and 36-fold (NAD-linked reaction) and 53-fold (NADP-linked reaction) for the K21Q enzyme . The Km for NADP+ was unchanged in both mutant enzymes . The Km for NAD+ was increased 1.5- and 3.2-fold, compared to the wild-type enzyme, in the K21R and K21Q enzymes, respectively . For the K21R enzyme the kcat for the NAD- and NADP-linked reactions was unchanged . The kcat for the K21Q enzyme was increased in the NAD-linked reaction by 26% and decreased by 30% in the NADP-linked reaction from the values for the wild-type enzyme . The data are consistent with Lys-21 participating in the binding of the phosphate group of the substrate to the enzyme via charge-charge interaction. J Biol Chem, 1992 Feb 15, 267(5), 3096 - 100 Iron-catalyzed oxidative modification of glucose-6-phosphate dehydrogenase from Leuconostoc mesenteroides . Structural and functional changes; Szweda LI et al.; As a variety of eukaryotic cells age, the specific activity of glucose-6-phosphate dehydrogenase (Glu-6-PDH) declines as much as 50% . Because of the central role of this enzyme in metabolism, it is important to define factors responsible for this loss in enzyme activity . We report that Glu-6-PDH from Leuconostoc mesenteroides is rapidly inactivated by micromolar concentrations of Fe2+ and H2O2 . Inactivation correlated with the formation of one carbonyl functionality/enzyme subunit, indicating that inactivation is the result of site-specific oxidative modification . Our results suggest that Fe2+ binds to the glucose 6-phosphate binding site and that interaction of the enzyme-bound Fe2+ with H2O2 leads to the oxidative modification of amino acids essential for enzyme activity . Partially inactivated enzyme remained predominantly in the dimeric form, and no change in the apparent affinity of the remaining active subunits for substrate was observed . Partial inactivation did, however, lead to a decrease in the thermal stability of the remaining activity . This decrease in thermal stability could be largely overcome by the addition of glucose 6-phosphate . Thus, although exposure to H2O2 and Fe2+ results in the irreversible inactivation of Glu-6-PDH, the resulting modification is selective, leads to the formation of heterodimers of both active and inactive subunits, and does not appear to cause large scale structural changes . Our results demonstrate the inherent susceptibility of Glu-6-PDH from L . mesenteroides to modification by an oxidation system known to exist in vivo . An assessment of the physiological significance of Fe(2+)-catalyzed oxidation of Glu-6-PDH awaits extension of these studies to mammalian sources known to accumulate less active or inactive forms of the enzyme as a function of age. Appl Biochem Biotechnol, 1991 Dec, 31(3), 237 - 46 Inhibition of dextransucrase by alpha-D-glucose derivatives; Michiels AG et al.; alpha-D-Glucopyranosyl fluoride was modified at positions 2, 3, or 5 and these analogs were tested as substrates and inhibitors of dextransucrase from Leuconostoc mesenteroides B-512F . The analogs studied were 2-deoxy-2-fluoro-alpha-D-glucopyranosyl fluoride, 3-deoxy-3-fluoro-alpha-D-glucopyranosyl fluoride, 3-deoxy-3-thio-alpha-D-glucopyranosyl fluoride, and 5-thio-alpha-D-glucopyranosyl fluoride . Kinetic constants for alpha-D-glucopyranosyl fluoride were also determined . None of the alpha-D-glucopyranosyl fluorides were accepted as substrates for dextransucrase . 2-Deoxy-2-fluoro-alpha-D-glucopyranosyl fluoride, 3-deoxy-3-fgluoro-alpha-D-glucopyranosyl fluoride, and 3-deoxy-3-thio-alpha-D-glucopyranosyl fluoride were competitive inhibitors with Ki values of 63, 93, and 53 mM, respectively . The Km for alpha-D-glucopyranosyl fluoride was found to be 26 mM . The data indicate that the hydroxyl groups at C2 and C3 are important for proper binding of alpha-D-glucopyranosyl fluoride for the active site of dextransucrase and that the C3-hydroxyl probably acts as a hydrogen-bond donor. East Afr Med J, 1991 Dec, 68(12), 969 - 74 Occurrence of Leuconostoc mesenteroides and leuconostoc-like organisms in Lagos, Nigeria; Idika N et al.; A total of 91 catalase--negative Gram-positive coccal isolates obtained from 245 clinical specimens in Lagos were characterized . Ten (11.0%) of the isolates were vancomycin resistant, they fermented glucose, sucrose, fructose, lactose, mannose, mannitol, ribose, salicin, sorbitol, arabinose and xylose with acid production . One of the isolates produced in addition gas inclusive and ethanol, thus identified as Leuconostoc mesenteroides . The ten vancomycin-resistant Gram-positive coccal organisms (VRGPC) showed variable sensitivity patterns to penicillin, tetracycline, erythromycin, ampicillin, streptomycin, chloramphenicol, cloxacillin and co-trimoxazole . The possible role of Leuconostoc spp . and VRGPC in clinical infections in hospital setting is still to be defined. Appl Environ Microbiol, 1991 Dec, 57(12), 3450 - 5 Detection and activity of a bacteriocin produced by Leuconostoc mesenteroides; Daba H et al.; Leuconostoc mesenteroides UL5 was found to produce a bacteriocin, referred as mesenterocin 5, active against Listeria monocytogenes strains but with no effect on several useful lactic acid bacteria . The antimicrobial substance is a protein, since its activity was completely destroyed following protease (pronase) treatment . However, it was relatively heat stable (100 degrees C for 30 min) and partially denaturated by chloroform . The inhibitory effect of the bacteriocin on sensitive bacterial strains was determined by a critical-dilution micromethod . Mutants of L . mesenteroides UL5 which had lost the capacity to produce the bacteriocin were obtained . The mutant strain was stable and phenotypically identical to parental cells and remained resistant to the bacteriocin . Sodium dodecyl sulfate-polyacrylamide gel electrophoresis was used to detect bacteriocin activity corresponding to an apparent molecular mass of about 4.5 kDa. Carbohydr Res, 1991 Sep 18, 217, 201 - 11 Maltodextrin acceptor reactions of Streptococcus mutans 6715 glucosyltransferases; Fu DT et al.; The maltodextrin (maltose through maltoheptaose) acceptor reactions of two Streptococcus mutans 6715 glucosyltransferases (GTF-I and GTF-S) were studied . The acceptor product structures were determined by comparing them with the known structures of the acceptor products of Leuconostoc mesenteroides B-512FM dextransucrase (EC 2.4.1.5) and L . mesenteroides B-1355 alternansucrase (EC 2.4.1.140) . When reacted with maltose (G2), both GTF-I and GTF-S transferred a D-glucopyranose from sucrose to the nonreducing glucosyl residue to give panose (6(2)-alpha-D-glucopyranosyl maltose) . Panose then served as an acceptor to give two further acceptor products, 6(2)-alpha-isomaltosyl maltose and 6(2)-alpha-nigerosyl maltose . 6(2)-alpha-Isomaltosyl maltose then went on to serve as an acceptor to give a series of homologous acceptor products with isomaltodextrin chains attached to C-6 of the nonreducing-end residue of maltose, while 6(2)-alpha-nigerosyl maltose did not further react . When reacted with other maltodextrins (G3-G7), both GTF-I and GTF-S transferred a D-glucopyranose to C-6 of either the nonreducing-end or the reducing-end residues of the maltodextrins, forming alpha(1----6) linkages . When D-glucopyranose was transferred to the nonreducing-end residue by GTF-I or GTF-S, the first product was also an acceptor to give the second product, which then served as an acceptor to give the third product, etc., to give a homologous series of products . When D-glucopyranose was transferred to the reducing-end residue, the acceptor product that formed did not readily serve as an acceptor, or served only as a very poor acceptor, to give a small amount of the next homologue, as was the case for G7 with GTF-S . In addition, GTF-I also transferred D-glucopyranose to the reducing-end or to the nonreducing-end residue of maltotriose, forming alpha(1----3) linkages, to give 3(3)-alpha-D-glucopyranosyl maltotriose and 3(1)-alpha-D-glucopyranosyl maltotriose . Neither of these acceptor products further served as acceptors to give a homologous series . Under equivalent conditions of equimolar amounts of acceptor and sucrose, maltose and maltotriose are much better acceptors with GTF-I than they are with GTF-S, which is better than L . mesenteroides B-512FM dextransucrase . The three enzymes display significantly different efficiencies for the different maltodextrin acceptor reactions, GTF-I and GTF-S having much higher efficiencies than L . mesenteroides B-512FM dextransucrase. J Gen Microbiol, 1991 Sep, 137 ( Pt 9), 2135 - 9 Lysogeny in Leuconostoc oenos; Arendt EK et al.; Thirty strains of Leuconostoc oenos were exposed to mitomycin C to induce lysogenic bacteriophages . Lysis curves typical for lysogenic strains were obtained with 19 strains . Indicator strans were found for 17 of these phages . Five were characterized by electron microscopy, lytic spectrum, molecular masses of the proteins, sequencing of five N-terminal amino acids of the two major proteins and DNA analysis (restriction patterns, cross hybridization) . The results revealed a very close relationship between the phages . Hybridization experiments between the DNAs of the temperate phages and the appropriate lysogenic strains revealed phage-related sequences in the DNA of the lysogenic strain. J Biol Chem, 1991 Jul 15, 266(20), 13028 - 34 Cloning of the gene and amino acid sequence for glucose 6-phosphate dehydrogenase from Leuconostoc mesenteroides; Lee WT et al.; Amino acid sequencing of glucose 6-phosphate dehydrogenase (Glc6PD) from Leuconostoc mesenteroides yielded sequence for over 75% of the protein . Two oligonucleotides based on the amino acid sequence were used to isolate a partial Glc6PD gene clone (pLmz delta N65), from a pUC9 library, containing 85% of the coding sequence and the 3'-untranslated DNA, but lacking the 5'-noncoding DNA sequence and the portion of the gene encoding the 65 N-terminal amino acids . Attempts to obtain a full-length clone from lambda libraries were unsuccessful, possibly due to restriction of L . mesenteroides DNA by Escherichia coli host cells . The 5'-untranslated DNA was amplified by the polymerase chain reaction and partially sequenced . To obtain unmodified DNA for the gene, oligonucleotides corresponding to the 5'- and 3'-noncoding sequences were used to amplify the gene by the polymerase chain reaction, and a 1.8-kilobase pair fragment was isolated and cloned into pUC19 . The recombinant plasmid, pLmz, contains the entire Glc6PD gene and expresses the gene in E . coli . pLmz was sequenced showing that the enzyme consists of 485 amino acids . L . mesenteroides Glc6PD is 31% identical to the human enzyme. FEMS Microbiol Lett, 1991 Jul 15, 66(1), 55 - 9 A phylogenetic analysis of an atypical leuconostoc: description of Leuconostoc fallax sp . nov; Martinez-Murcia AJ et al.; The 16S rRNA sequence of an unknown leuconostoc originally isolated from sauerkraut was investigated by reverse transcription . A comparison of the sequence with those from other lactic acid bacteria revealed the unknown organism represents a new albeit peripheral line within the genus Leuconostoc sensu stricto . A new species, Leuconostoc fallax, is proposed for this organism . The type strain is DSM 20189. Diagn Microbiol Infect Dis, 1991 Jul-Aug, 14(4), 337 - 45 In vitro activity of 43 antimicrobial agents tested against ampicillin-resistant enterococci and gram-positive species resistant to vancomycin; Yamane N et al.; A total of 57 strains of ampicillin-resistant and -susceptible enterococci representing 10 species and 23 strains of vancomycin-resistant Gram-positive bacteria (Leuconostoc and Pediococcus) were tested to determine their susceptibility to 43 antimicrobial agents by the reference broth microdilution method . The drug MICs for the ampicillin-resistant enterococci were generally similar to those of ampicillin-susceptible strains, that is, highly resistant to cephalosporins, moderately susceptible or resistant to quinolones, and susceptible to "glycopeptides." Some investigational quinolones (PD127391, sparfloxacin, WIN57273), minocycline, and rifampin were highly active . Vancomycin-resistant strains were usually resistant to other "glycopeptides," for which correlation coefficients of MICs ranged from 0.881 to 0.978, except ramoplanin (MICs, 0.008-0.5 micrograms/ml) . Most isolates resistant to vancomycin were susceptible to the newer quinolones, penicillins, aminoglycosides, clindamycin, and erythromycin, but highly resistant to cephalosporins . Discrepancies between the MICs and MBCs for glycopeptides were noted (greater than or equal to 8-fold, MBC50/MIC50), but not for ramoplanin . The vancomycin disk test was in 96.1% absolute agreement by identifying res