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PubMed1995

Cloning, nucleotide sequence, and transcriptional analysis of the Pediococcus acidilactici L-(+)-lactate dehydrogenase gene.

Recombinant plasmids containing the Pediococcus acidilactici L-(+)-lactate dehydrogenase gene (ldhL) were isolated by complementing for growth under anaerobiosis of an Escherichia coli lactate dehydrogenase-pyruvate formate lyase double mutant. The nucleotide sequence of the ldhL gene predicted a protein of 323 amino acids showing significant similarity with other bacterial L-(+)-lactate dehydrogenases and especially with that of Lactobacillus plantarum. The ldhL transcription start points in P. acidilactici were defined by primer extension, and the promoter sequence was identified as TCAAT-(17 bp)-TATAAT. This sequence is closely related to the consensus sequence of vegetative promoters from gram-positive bacteria as well as from E. coli. Northern analysis of P. acidilactici RNA showed a 1.1-kb ldhL transcript whose abundance is growth rate regulated. These data, together with the presence of a putative rho-independent transcriptional terminator, suggest that ldhL is expressed as a monocistronic transcript in P. acidilactici.

Amino Acid Sequence↗
PubMed1995

Isolation and characterization of pediocin L50, a new bacteriocin from Pediococcus acidilactici with a broad inhibitory spectrum.

Lactic acid bacteria were isolated from Spanish dry-fermented sausages and screened for bacteriocin production. About 10% of the isolates produced antimicrobial substances when grown on solid media, but only 2% produced detectable activity in liquid media. Strain L50, identified as Pediococcus acidilactici, showed the strongest inhibitory activity and was active against members of all of the gram-positive genera tested. The strain produced a heat-stable bacteriocin when grown at 8 to 32 degrees C but not at 45 degrees C. The bacteriocin was purified to homogeneity. Its mass was determined to be 5,250.11 +/- 0.30 by electrospray mass spectrometry. The N terminus of the bacteriocin was blocked for sequencing by Edman degradation, but a partial sequence of 42 amino acids was obtained after cleavage of the peptide by cyanogen bromide. The sequence showed no similarity to those of other bacteriocins. Pediocin L50 appears to contain modified amino acids but not lanthionine or methyl-lanthionine.

Amino Acid Sequence↗
PubMed1997

Purification and partial characterization of a tripeptidase from Pediococcus pentosaceus K9.2.

A tripeptidase was purified from the cytoplasm of Pediococcus pentosaceus K9.2 by anion-exchange chromatography, gel filtration chromatography, and high-performance liquid chromatography. The molecular mass of the enzyme was estimated by gel filtration at 100,000 Da. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis of the purified peptidase showed one protein band of 45,000 Da. Optimal enzyme activity was obtained at pH 7.0 and at 50 degrees C. The peptidase hydrolyzed all tripeptides tested. Cleavage was not observed with dipeptides, oligopeptides, or amino acid-p-nitroanilide derivatives. Strong inhibition of activity was caused by EDTA, 1,10-phenanthroline, dithiothreitol, and beta-mercaptoethanol, whereas phenylmethylsulfonyl fluoride and sulfur-reactive reagents had no effect on peptidase activity. Mg2+, Mn2+, and Ca2+ stimulated the hydrolyzing activity of the enzyme. The 20 N-terminal amino acids of the tripeptidase from P. pentosaceus had 84% identity with those from the corresponding N-terminal region of the tripeptidase from Lactococcus lactis subsp. cremoris Wg2.

Amino Acid Sequence↗
PubMed2001

Decrease in cell surface galactose residues of Schizosaccharomyces pombe enhances its coflocculation with Pediococcus damnosus.

Pediococcus damnosus can coflocculate with Saccharomyces cerevisiae and cause beer acidification that may or may not be desired. Similar coflocculations occur with other yeasts except for Schizosaccharomyces pombe which has galactose-rich cell walls. We compared coflocculation rates of S. pombe wild-type species TP4-1D, having a mannose-to-galactose ratio (Man:Gal) of 5 to 6 in the cell wall, with its glycosylation mutants gms1-1 (Man:Gal = 5:1) and gms1Delta (Man:Gal = 1:0). These mutants coflocculated at a much higher level (30 to 45%) than that of the wild type (5%). Coflocculation of the mutants was inhibited by exogenous mannose but not by galactose. The S. cerevisiae mnn2 mutant, with a mannan content similar to that of gms1Delta, also showed high coflocculation (35%) and was sensitive to mannose inhibition. Coflocculation of P. damnosus and gms1Delta (or mnn2) also could be inhibited by gms1Delta mannan (with unbranched alpha-1,6-linked mannose residues), concanavalin A (mannose and glucose specific), or NPA lectin (specific for alpha-1,6-linked mannosyl units). Protease treatment of the bacterial cells completely abolished coflocculation. From these results we conclude that mannose residues on the cell surface of S. pombe serve as receptors for a P. damnosus lectin but that these receptors are shielded by galactose residues in wild-type strains. Such interactions are important in the production of Belgian acid types of beers in which mixed cultures are used to improve flavor.

Cell Wall↗
PubMed2003

Functional replacement of the Escherichia coli D-(-)-lactate dehydrogenase gene (ldhA) with the L-(+)-lactate dehydrogenase gene (ldhL) from Pediococcus acidilactici.

The microbial production of L-(+)-lactic acid is rapidly expanding to allow increased production of polylactic acid (PLA), a renewable, biodegradable plastic. The physical properties of PLA can be tailored for specific applications by controlling the ratio of L-(+) and D-(-) isomers. For most uses of PLA, the L-(+) isomer is more abundant. As an approach to reduce costs associated with biocatalysis (complex nutrients, antibiotics, aeration, product purification, and waste disposal), a recombinant derivative of Escherichia coli W3110 was developed that contains five chromosomal deletions (focA-pflB frdBC adhE ackA ldhA). This strain was constructed from a D-(-)-lactic acid-producing strain, SZ63 (focA-pflB frdBC adhE ackA), by replacing part of the chromosomal ldhA coding region with Pediococcus acidilactici ldhL encoding an L-lactate dehydrogenase. Although the initial strain (SZ79) grew and fermented poorly, a mutant (SZ85) was readily isolated by selecting for improved growth. SZ85 exhibited a 30-fold increase in L-lactate dehydrogenase activity in comparison to SZ79, functionally replacing the native D-lactate dehydrogenase activity. Sequencing revealed mutations in the upstream, coding, and terminator regions of ldhL in SZ85, which are presumed to be responsible for increased L-lactate dehydrogenase activity. SZ85 produced L-lactic acid in M9 mineral salts medium containing glucose or xylose with a yield of 93 to 95%, a purity of 98% (based on total fermentation products), and an optical purity greater than 99%. Unlike other recombinant biocatalysts for L-lactic acid, SZ85 remained prototrophic and is devoid of plasmids and antibiotic resistance genes.

Culture Media↗
PubMed1970

Transport of folinate and related compounds in Pediococcus cerevisiae.

The properties of folinate and 5-methyltetrahydrofolate (5-CH(3)-H(4)PteGlu) transport mechanism of Pediococcus cerevisiae were studied. The uptake was dependent on temperature, pH (optimum for both compounds at pH 6.0), and glucose. Iodoacetate, potassium fluoride, and sodium azide inhibited the uptake. 5-CH(3)-H(4)-PteGlu was apparently not metabolized but folinate was metabolized. Metabolism of folinate was reduced by preincubation of cells with fluorodeoxyuridine. The transport system for folinate and 5-CH(3)-H(4)PteGlu were specific for the l-isomers. Pteroylglutamate, aminopterin, and amethopterin did not interfere with the uptake. Tetrahydrofolate competed with the uptake of folinate. The transport of folinate and 5-CH(3)-H(4)PteGlu at 37 C conformed to Michaelis-Menten kinetics; apparent K(m) for both compounds was 4.0 x 10(-7)m, and the V(max) for folinate was 1.0 x 10(-10) moles per min per mg (dry weight) and for 5-CH(3)-H(4)PteGlu it was 1.6 x 10(-10) moles per min per mg (dry weight). Both compounds accumulated in the intracellular pool at a concentration about 80- to 140-fold higher than that in the external medium. Folinate inhibited competitively the uptake of 5-CH(3)-H(4)PteGlu with a K(i) of 0.4 x 10(-7)m. Unlike 5-CH(3)-H(4)PteGlu, which accumulated only at 37 C, folinate was also taken up at 0 C by a glucose- and temperature-independent process, which was not affected by the metabolic inhibitors mentioned above. Since at 0 C the intracellular concentration of folinate was also considerably higher than the external, binding of the substrate to some cellular component is assumed. The finding of an efficient transport system for l-5-CH(3)-H(4)PteGlu is of special interest, since this compound has no growth-promoting activity for P. cerevisiae.

Aminopterin↗
PubMed1973

Carrier-mediated transport of folate in a mutant of Pediococcus cerevisiae.

A mutant strain of Pediococcus cerevisiae (P. cerevisiae/PteGlu) was isolated which grows on low-folate (PteGlu) concentrations (200 pg/ml). The growth response of the parent and mutant strains to folinate (5-CHO-H(4)PteGlu) was the same. The transport of (14)C-PteGlu by P. cerevisiae/PteGlu was temperature-dependent (Q(10) between 27 C and 37 C was about 2), energy-dependent, and pH-dependent and was inhibited by iodoacetate, 2,4-dinitrophenol, potassium fluoride, and sodium azide. The uptake obeyed saturation kinetics with an apparent K(m) of 6.6 x 10(-6) M and V(max) of 4.0 x 10(-10) mol per min per mg (dry weight). At the steady state the intracellular concentration of PteGlu was 120-fold higher from that of the medium. Reduced folates like 5-CHO-H(4)PteGlu and methyl-tetrahydrofolate (5-CH(3)-H(4)PteGlu) as well as 2,4-diaminoanalogues (amethopterin and aminopterin) were shown to compete for the PteGlue-carrier.

Aminopterin↗
PubMed1975

Production of racemic lactic acid in Pediococcus cerevisiae cultures by two lactate dehydrogenases.

Nicotinamide adenine dinucleotide (NAD)-dependent d(minus)-and l(plus)-lactate dehydrogenases have been partially purified 89- and 70-fold simultaneously from cell-free extracts of Pediococcus cerevisiae. Native molecular weights, as estimated from molecular sieve chromatography and electrophoresis in nondenaturing polyacrylamide gels, are 71,000 to 73,000 for d(minus)-lactate dehydrogenase and 136,000 to 139,000 for l(plus)-lactate dehydrogenase. Electrophoresis in sodium dodecyl sulfate-containing gels reveals subunits with approximate molecular weights of 37,000 to 39,000 for both enzymes. By lowering the pyruvate concentration from 5.0 to 0.5 mM, the pH optimum for pyruvate reduction by d(minus)-lactate dehydrogenase decreases from pH 8.0 to 3.6. However, l(plus)-lactate dehydrogenase displays an optimum for pyruvate reduction between pH 4.5 and 6.0 regardless of the pyruvate concentration. The enzymes obey Michaelis-Menten kinetics for both pyruvate and reduced NAD at pH 5.4 and 7.4, with increased affinity for both substrates at the acid pH. alpha-Ketobutyrate can be used as a reducible substrate, whereas oxamate has no inhibitory effect on lactate oxidation by either enzyme. Adenosine triphosphate causes inhibition of both enzymes by competition with reduced NAD. Adenosine diphosphate is also inhibitory under the same conditions, whereas NAD acts as a product inhibitor. These results are discussed with relation to the lactate isomer production during the growth cycle of P. cerevisiae.

Adenosine Triphosphate↗
PubMed1975

Pediococcus cerevisiae mutant with altered transport of folates.

A Pediococcus cerevisiae mutant that actively accumulated folate (PteGlu), in contrast to the wild-type, was also found to exhibit changes in the pattern of uptake of 5-methyl-tetrahydrofolate (5-CH3-H4PteGlu) and amethopterin. Most of the 5-CH3-H4PteGlue accumulated through a glucose- and temperature-dependent process, and a concentrative uptake was also found in gluocse-starved cells and in cells incubated at OC. About 75% of the accumulated 5-CH3-H4PteGlu exchanged with amethopterin. In contrast to the wild type, the mutant accumulated both diastereoisomers of 5-CH3-H4PteGlue by glucose-dependent and glucose-independent processes. Amethopterin and PteGlue competitively inhibited the uptake in both processes, with an apparent lower affinity of the carrier for PteGlu than for the analogue. p-Chloromercuribenzoate strongly inhibited the uptake (75%). The p-chloromercuribenzoate-nonsusceptible and temperature-independent uptake was also competed by amethopterin. Metabolic poisons like sodium azide, potassium fluoride, iodoacetate, and 2,4-dimitrophenol inhibited the glucose-dependent process. Uptake, in the absence of glucose, was enhanced by sodium azide and potassium fluoride.

Azides↗
PubMed1982

Physiological and enzymatic properties of a thymidine-requiring Pediococcus cerevisiae mutant.

We describe the isolation and characterization of a Pediococcus cerevisiae thymidine-requiring mutant and its thymidine-independent revertant. The mutant strain lacked thymidylate synthetase activity and had an absolute requirement for low concentrations (2 micrograms/ml) of thymidine in addition to a requirement for N-5-formyl tetrahydrofolic acid (folinate). Even at high concentrations (up to 500 micrograms/ml), thymine could not replace thymidine. In contrast to its wild-type parent, which grows only on folinate, the thymidine-requiring mutant (Thy- Fol+) was able to take up and grow on picogram quantities of unreduced folic acid. When both strains were grown on folinate, the Thy- Fol+ strain was at least 10(3)-fold more resistant to the folic acid analogs aminopterin and methotrexate than the wild-type strain. On the other hand, when grown on folic acid, the Thy- Fol+ strain was as sensitive to the folic acid analogs as the Thy+ Fol+ strain and was 10(2)-fold more sensitive than the wild-type strain grown on folinate. The thymidine-independent revertant (Thy+ Fol+) regained the wild-type level of thymidylate synthetase activity, but maintained the ability to take up and grow on unreduced folic acid like its Thy- Fol+ parent.

Aminopterin↗
PubMed1989

Correlation between depression of catabolite control of xylose metabolism and a defect in the phosphoenolpyruvate:mannose phosphotransferase system in Pediococcus halophilus.

Pediococcus halophilus X-160 which lacks catabolite control by glucose was isolated from nature (soy moromi mash). Wild-type strains, in xylose-glucose medium, utilized glucose preferentially over xylose and showed diauxic growth. With wild-type strain I-13, xylose isomerase activity was not induced until glucose was consumed from the medium. Strain X-160, however, utilized xylose concurrently with glucose and did not show diauxic growth. In this strain, xylose isomerase was induced even in the presence of glucose. Glucose transport activity in intact cells of strain X-160 was less than 10% of that assayed in strain I-13. Determinations of glycolytic enzymes did not show any difference responsible for the unique behavior of strain X-160, but the rate of glucose-6-phosphate formation with phosphoenolpyruvate (PEP) as a phosphoryl donor in permeabilized cells was less than 10% of that observed in the wild type. Starved P. halophilus I-13 cells contained the glycolytic intermediates 3-phosphoglycerate, 2-phosphoglycerate, and PEP (PEP pool). These were consumed concomitantly with glucose or 2-deoxyglucose uptake but were not consumed with xylose uptake. The glucose transport system in P. halophilus was identified as a PEP:mannose phosphotransferase system on the basis of the substrate specificity of PEP pool-starved cells. It is concluded that, in P. halophilus, this system is functional as a main glucose transport system and that defects in this system may be responsible for the depression of glucose-mediated catabolite control.

Aldose-Ketose Isomerases↗
PubMed1994

The Escherichia coli Dga (MurI) protein shares biological activity and structural domains with the Pediococcus pentosaceus glutamate racemase.

The Pediococcus pentosaceus glutamate racemase gene product complemented the D-glutamate auxotrophy of Escherichia coli WM335. Amino acid sequence analysis of the two proteins revealed 28% identity, primarily in six clusters scattered throughout the sequence. Further analyses indicated secondary structure similarities between the two proteins. These data support a recent report that the dga (murI) gene product is a glutamate racemase.

Amino Acid Isomerases↗
PubMed1995

Pediococcus acidilactici ldhD gene: cloning, nucleotide sequence, and transcriptional analysis.

The gene encoding D-lactate dehydrogenase was isolated on a 2.9-kb insert from a library of Pediococcus acidilactici DNA by complementation for growth under anaerobiosis of an Escherichia coli lactate dehydrogenase and pyruvate-formate lyase double mutant. The nucleotide sequence of ldhD encodes a protein of 331 amino acids (predicted molecular mass of 37,210 Da) which shows similarity to the family of D-2-hydroxyacid dehydrogenases. The enzyme encoded by the cloned fragment is equally active on pyruvate and hydroxypyruvate, indicating that the enzyme has both D-lactate and D-glycerate dehydrogenase activities. Three other open reading frames were found in the 2.9-kb insert, one of which (rpsB) is highly similar to bacterial genes coding for ribosomal protein S2. Northern (RNA) blotting analyses indicated the presence of a 2-kb dicistronic transcript of ldhD (a metabolic gene) and rpsB (a putative ribosomal protein gene) together with a 1-kb monocistronic rpsB mRNA. These transcripts are abundant in the early phase of exponential growth but steadily fade away to disappear in the stationary phase. Primer extension analysis identified two distinct promoters driving either cotranscription of ldhD and rpsB or transcription of rpsB alone.

Amino Acid Sequence↗
PubMed2000

Inducible metabolism of phenolic acids in Pediococcus pentosaceus is encoded by an autoregulated operon which involves a new class of negative transcriptional regulator.

Pediococcus pentosaceus displays a substrate-inducible phenolic acid decarboxylase (PAD) activity on p-coumaric acid. Based on DNA sequence homologies between the three PADs previously cloned, a DNA probe of the Lactobacillus plantarum pdc gene was used to screen a P. pentosaceus genomic library in order to clone the corresponding gene of this bacteria. One clone detected with this probe displayed a low PAD activity. Subcloning of this plasmid insertion allowed us to determine the part of the insert which contains a 534-bp open reading frame (ORF) coding for a 178-amino-acid protein presenting 81.5% of identity with L. plantarum PDC enzyme. This ORF was identified as the padA gene. A second ORF was located just downstream of the padA gene and displayed 37% identity with the product of the Bacillus subtilis yfiO gene. Subcloning, transcriptional analysis, and expression studies with Escherichia coli of these two genes under the padA gene promoter, demonstrated that the genes are organized in an autoregulated bicistronic operonic structure and that the gene located upstream of the padA gene encodes the transcriptional repressor of the padA gene. Transcription of this pad operon in P. pentosaceus is acid phenol dependent.

Amino Acid Sequence↗
PubMed1968

Effect of folinate on thymidine uptake by Pediococcus cerevisiae.

Uptake of (3)H-thymidine by resting cells of Pediococcus cerevisiae was found to be energy- and temperature-dependent. The pH optimum was between 6.5 and 8.0, and after 2 min of incubation most of the radioactivity was found in the deoxyribonucleic acid (DNA) fraction. Iodoacetate at a concentration of 10(-2)m caused a 50% inhibition of uptake. Preincubation of resting cells for 10 min with folinate (10(-3)mu mole/ml) diminished the (3)H-thymidine uptake by 75%. In growing cells, the folinate-induced inhibition was still more striking. Deoxyuridine augmented the folinate effect, whereas fluorodeoxyuridine and aminopterin or amethopterin abolished it. Preincubation with folinate did not interfere with the uptake of (3)H-amethopterin, and thus the inhibitor did not compete for uptake sites within the cell. The role of these inhibitors in reversing the folinate effect is discussed. Cells preincubated with folinate showed an increased incorporation of (14)C-uracil into DNA, presumably after prior conversion to thymidylate. We concluded that the folinate effect was due to stimulation of de novo thymidylate synthesis with concomitant inhibition of the uptake of external thymidine.

Aminopterin↗
PubMed1990

Septicemia caused by vancomycin-resistant Pediococcus acidilactici.

A case of septicemia caused by vancomycin-resistant Pediococcus acidilactici is discussed. This appears to be the first reported case of septicemia caused by this organism. The characteristics and antimicrobial susceptibilities of this organism are described.

Bacterial Infections↗
PubMed1996

Proinflammatory effect of Pediococcus pentosaceus, a bacterium used as hay preservative.

Bacterial cultures, such as Pediococcus pentosaceus, are used to treat hay with the objective of preventing hay heating and moulding, and thus, the development of the microbial growth which causes farmer's lung. The aim of this study was to investigate whether such bacterial cultures have the potential to induce a pulmonary inflammatory response. Mice were instilled 3 days week-1 for 3 weeks with either saline or nonviable preparations of P. pentosaceus, Saccharopolyspora rectivirgula, Lactococcus lactis (control bacteria) or with the combinations of S. rectivirgula and P. pentosaceus. P. pentosaceus induced a significant inflammatory response in the lung which was similar to that produced by S. rectivirgula. L. lactis produced a response of a lower intensity. The total number of cells in bronchoalveolar lavage were: S. rectivirgula: 6.4 x 10(5) cells.mL-1; P. pentosaceus: 4.3 x 10(5) cells.mL-1; S. rectivirgula + P. pentosaceus: 5.4 x 10(5) cells.mL-1, L. lactis: 6.8 x 10(5) cells.mL-1 and saline group 3.7 x 10(4) cells.mL-1. The lung index was higher in S. rectivirgula+P. pentosaceus and P. pentosaceus groups than in S. rectivirgula, L. lactis and saline groups. The quantity of specific immunoglobulin G and A (IgG and IgA) to P. pentosaceus and L. lactis levels (in the blood and/or lavage fluid) were similar to those against S. rectivirgula. In mice, P. pentosaceus has the potential to induce a similar inflammatory response in the lung as S. rectivirgula, which is the most common antigen responsible for farmer's lung disease in Quebec. Further studies are needed to verify whether farmers can develop farmer's lung or other lung responses to this new potential antigen.

Animals↗