Search results for "malate"
showing 10 items of 67 documents
Influence of carboxylic acids on the stereospecific nicotinamide adenine dinucleotide-dependent and nicotinamide adenine dinucleotide-independent lac…
1971
Leuconostoc mesenteroides increased its lactic acid production from glucose threefold when malic acid was added to the culture. This increase resulted also in a reduction of the ratio of d -lactic acid to l -lactic acid (31.5 to 1.23). Addition of malic acid increased 6.5-fold the specific activity of nicotinamide adenine dinucleotide (NAD)-linked l -lactate dehydrogenase and increased 3.2-fold that of NAD-linked d -lactate dehydrogenase. The Michaelis constant ( K m ) for NAD of the NAD-linked l -lactate dehydrogenase increased with the addition of malate, but no change was observed in the K m values for the respective d -enzyme. The effect of carboxylic acids on the NAD-linked l -lactate…
Regulation of aerobic and anaerobic D-malate metabolism of Escherichia coli by the LysR-type regulator DmlR (YeaT).
2010
ABSTRACT Escherichia coli K-12 is able to grow under aerobic conditions on d -malate using DctA for d -malate uptake and the d -malate dehydrogenase DmlA (formerly YeaU) for converting d -malate to pyruvate. Induction of dmlA encoding DmlA required an intact dmlR (formerly yeaT ) gene, which encodes DmlR, a LysR-type transcriptional regulator. Induction of dmlA by DmlR required the presence of d -malate or l - or meso -tartrate, but only d -malate supported aerobic growth. The regulator of general C 4 -dicarboxylate metabolism (DcuS-DcuR two-component system) had some effect on dmlA expression. The anaerobic l -tartrate regulator TtdR or the oxygen sensors ArcB-ArcA and FNR did not have a m…
Definitive host influences the proteomic profile of excretory/secretory products of the trematode Echinostoma caproni
2016
Background Echinostoma caproni is an intestinal trematode extensively used as experimental model for the study of factors that determine the course of intestinal helminth infections, since this markedly depends on the host species. Although the host-dependent mechanisms for either chronic establishment or early parasite rejection have been broadly studied, little is known regarding the parasite response against different host environments. Methods To identify host-dependent differentially expressed proteins, a comparative proteomic analysis of the excretory/secretory products released from E. caproni adults, isolated from hosts displaying different compatibility with this trematode, was per…
D-Malic enzyme of Pseudomonas fluorescens.
1982
By the enrichment culture technique 14 gram-negative bacteria and two yeast strains were isolated that used D(+)-malic acid as sole carbon source. The bacteria were identified as Pseudomonas putida, Pseudomonas fluorescens, Pseudomonas aeruginosa and Klebsiella aerogenes. In cell-free extracts of P. fluorescens and P. putida the presence of malate dehydrogenase, D-malic enzyme (NAD-dependent) and L-malic enzyme (NADP-dependent) was demonstrated. D-Malic enzyme from P. fluorescens was purified. Stabilization of the enzyme by 50 mM ammonium sulphate an 1 mM EDTA was essential. Preparation of D-malic enzyme that gave one band with disc gel electrophoresis showed a specific activity of 4-5 U/mg…
Effects of yeast proteolytic activity on Oenococcus oeni and malolactic fermentation
2006
International audience; Alcoholic fermentation of synthetic must was performed using either Saccharomyces cerevisiae or a mutant Delta pep4, which is deleted for the proteinase A gene. Fermentation with the mutant Delta pep4 resulted in 61% lower levels of free amino acids, and in 62% lower peptide concentrations at the end of alcoholic fermentation than in the control. Qualitative differences in amino acid composition were observed. Changes observed in amino acids in peptides were mainly quantitative. After alcoholic fermentation each medium was inoculated with Oenococcus oeni. Malolactic fermentation in the medium with the Delta pep4 strain took 10 days longer than the control. This diffe…
Effectiveness of salivary stimulation using xylitol-malic acid tablets as coadjuvant treatment in patients with gastro-oesophageal reflux disease : e…
2020
[Background] Besides dental erosion syndrome, other oral syndromes could benefit from the stimulation of sali-vary secretion, in patients with gastro-oesophageal reflux disease (GORD). Our aims is evaluate the improvement of oral extra-oesophageal manifestations in patients with GORD using xylitol–malic acid tablets to stimulate salivary secretion.
Genetic organization of the mle locus and identification of a mleR-like gene from Leuconostoc oenos
1996
Characterization of the mle locus harboring the malolactic enzyme gene mleA and malate permease gene mleP from Leuconostoc oenos was completed in this study by mRNA analysis. Northern (RNA) blot experiments revealed a 2.6-kb transcript, suggesting an operon structure harboring mleA and mleP genes. Primer extension analysis showed that the mle operon has a single transcription start site located 17 nucleotides upstream of the ATG translation start site for the mleA gene. We found sequences, TTGACT and TATGAT (which are separated by 18 bp), that are closely related to the gram-positive and Escherichia coli consensus promoter sequences. Upstream of the mleA gene, an 894-bp open reading frame t…
Diurnal Regulation of Leaf Water Status in High- and Low-Mannitol Olive Cultivars
2014
The role of mannitol and malic acid in the regulation of diurnal leaf water relations was investigated in ‘Biancolilla’ (high-mannitol) and ‘Cerasuola’ (low-mannitol) olive trees. Photosynthetic photon flux density (PPFD), vapor pressure deficit (VPD), stomatal conductance (gs), transpiration rate (T), relative water content (RWC), mannitol and malic acid were measured in ‘Biancolilla’ and ‘Cerasuola’ leaves during a dry and hot day of summer in Sicily. In general, leaves of ‘Biancolilla’ trees exhibited greater mannitol content, higher gs and T, but lower RWC than leaves of ‘Cerasuola’ trees. Differences in gs and T between the two cultivars were evident mainly in mid to late morning. ‘Bia…
Absence of malolactic activity is a characteristic of H+-ATPase-deficient mutants of the lactic acid bacterium Oenococcus oeni.
2003
ABSTRACT The lack of malolactic activity in H + -ATPase-deficient mutants of Oenococcus oeni selected previously was analyzed at the molecular level. Western blot experiments revealed a spot at 60 kDa corresponding to the malolactic enzyme only in the parental strain. Moreover, the mleA transcript encoding the malolactic enzyme was not detected by reverse transcription (RT)-PCR analysis of mutants. These results suggest that the malolactic operon was not transcribed in ATPase-deficient mutants. The mleR gene encoding a LysR-type regulatory protein which should be involved in expression of the malolactic genes was described previously for O. oeni . Results obtained in this study show that th…
Amino acids and volatile compounds in wines from Cabernet Sauvignon and Tempranillo varieties subjected to malolactic fermentation in barrels
2012
The aim of the present paper is to compare the behaviour of industrial lactic bacteria and indigenous bacteria of the cellar when malolactic fermentation was carried out in barrels. The effects of these bacteria on the concentration of metabolised amino acids during malolactic fermentation and on the composition of volatile compounds both before and after malolactic fermentation are studied. The experiment was performed with wines of the Tempranillo and Cabernet Sauvignon varieties. An analysis has been made of the easily extractable volatile compounds of the wood and the compounds from the grapes, and the action of the yeasts during the alcoholic fermentation. Acetoin and diacetyl decreas…