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PubMed1990

Degradation pathway of kinins in tumor ascites and inhibition by kininase inhibitors: analysis by HPLC.

We have recently found presence of a high concentration of a novel type of kinin, hydroxyprolyl3-bradykinin (Hyp3-BK) in human tumor ascites in addition to conventional bradykinin (BK). Because of their potential physiological activity, it is of interest to know how these bradykinins can be degraded in ascites. Degradation of two synthetic kinins, BK and Hyp3-BK, added to the ascitic fluid from patients with ovarian carcinoma and hepatoma, were analyzed by reversed phase HPLC. Both kinins were degraded into their desArg9-BK or -Hyp3-BK and desPhe8-Arg-9-BK or -Hyp3-BK products following incubation with the ascitic fluid. The rate of the degradation of BK and Hyp3-BK was the same. The formation of desArg9-BK was completely inhibited by kininase I inhibitor, while the formation of desPhe8-Arg9-BK was not completely inhibited by a kininase II inhibitor. The degradation of both kinins was inhibited completely by EDTA. The results indicate the presence of other metalloprotease(s) which cleaves kinins in the ascitic fluid, in addition to kininase I and kininase II. The carboxypeptidase A and carboxypeptidase B inhibitor, benzyl malic acid, failed to block degradation of both kinins. A rapid cleave of Phe-Arg into Phe and Arg was also found in the ascitic fluid. Thus, the major degradation products of kinins in the ascitic fluid were demonstrated to be either desArg9-BK or Hyp3-BK, desPhe8-Arg9-BK or -Hyp3-BK, phenylalanine and arginine. Lysyl-BK and lysylhydroxyprolyl3-BK were rapidly converted into BK and hydroxyprolyl3-BK by the ascitic fluid.

Amino Acid Sequence↗

PubMed2001

Effects of combined high-dose partial liquid ventilation and almitrine on pulmonary gas exchange and hemodynamics in an animal model of acute lung injury.

OBJECTIVES: To determine possible additive effects of combined high-dose partial liquid ventilation (PLV) and almitrine bismesylate (ALM) on pulmonary gas exchange and hemodynamics in an animal model of acute lung injury (ALI). DESIGN AND SETTING: Prospective, controlled animal study in an animal research facility of a university hospital. INTERVENTIONS: ALI was induced in 12 anesthetized and mechanically ventilated pigs by repeated wash-out of surfactant. After initiation of PLV with 30 ml/kg perfluorocarbon the animals were randomly assigned to receive either accumulating doses of ALM (0.5, 1.0, 2.0, 4.0, 8.0, and 16.0 micrograms/kg per minute) for 30 min each (n = 6) or the solvent malic acid (n = 6). MEASUREMENT AND RESULTS: Pulmonary gas exchange and hemodynamics were measured at the end of each infusion period. Compared to ALI, PLV alone significantly increased arterial oxygen partial pressure (PaO2) and decreased venous admixture (QVA/QT) and mean pulmonary artery pressure (MPAP). Administration of ALM did not result in a further improvement in PaO2, QVA/QT or MPAP compared to PLV alone but decreased PaO2 and increased QVA/QT and MPAP when 16 micrograms/kg per min ALM was compared to PLV alone. CONCLUSIONS: In an animal model of surfactant depletion induced ALI the combined treatment of PLV and ALM induced no significant improvement in pulmonary gas exchange or hemodynamics when compared to PLV alone. Moreover, high-dose ALM significantly impaired gas exchange and pulmonary hemodynamics.

Almitrine↗

PubMed2000

Dose-dependent effects of almitrine on hemodynamics and gas exchange in an animal model of acute lung injury.

OBJECTIVE: To determine the dose-response relationship of almitrine (Alm) on pulmonary gas exchange and hemodynamics in an animal model of acute lung injury (ALI). DESIGN: Prospective, randomized, controlled study. METHODS: Twenty anesthetized, tracheotomized and mechanically ventilated (FIO2 1.0) pigs underwent induction of ALI by repeated saline washout of surfactant. Animals were randomly assigned to either receive cumulating doses of Alm intravenously (0.5, 1.0, 2.0, 4.0, 8.0 and 16.0 micrograms.kg-1.min-1) for 30 min each (treatment; n = 10) or to receive the solvent malic acid (controls; n = 10). MEASUREMENTS AND RESULTS: Measurements of pulmonary gas exchange and hemodynamics were performed at the end of each infusion period. Alm < 4.0 micrograms.kg-1.min-1 improved arterial oxygen pressure (PaO2) (105 +/- 9 mmHg for Alm 1.0 vs 59 +/- 5 mmHg) and decreased intrapulmonary shunt (Qs/Qt) (32 +/- 4% for Alm 1.0 vs 46 +/- 4%) (P < 0.05). Alm > or = 8.0 micrograms.kg-1.min-1 did not improve pulmonary gas exchange compared to controls. When compared to low doses of Alm < 4.0 micrograms.kg-1.min-1, high doses > or = 8.0 micrograms.kg1.min-1 decreased PaO2 (58 +/- 11 mmHg for Alm 16.0) and increased Qs/Qt (67 +/- 10% for Alm 16.0) (P < 0.05). CONCLUSIONS: In experimental ALI, effects of almitrine on oxygenation are dose-dependent. Almitrine is most effective when used at low doses known to mimic hypoxic pulmonary vasoconstriction.

Almitrine↗

PubMed2003

Chemometric investigation of the efficiency of different TiO(2)-based catalysts as principal components of TOC photochemical sensors under development.

There is an increasing demand for measurement of organic carbon in solutions both in industry and in environmental research for the purpose of continuous water-quality monitoring. Practically all the methods used are based on a catalytic system in which metal oxides play a major role. The development of a new TOC/DOC measurement system, in our work, uses a mixed anatase-rutile form of TiO(2 )as catalyst of the mineralisation process, and direct measurement of the CO(2) produced, by a gaseous diffusion electrode. The entire research is based on heterogeneous catalysis using an immobilised catalyst, which can offer considerable advantages over other methods of catalysis. Four different catalytic systems were analysed. Three involved thermal immobilisation of TiO(2) on glass supports (glass spheres and glassy particulates) or on an Al metal grid. One further system consisted of direct oxidation of a Ti grid at high temperatures. The system was illuminated using a 350 nm UV source (350 mW cm(-2)) contained in a home-made measurement cell. Five molecules-malic acid, pentachlorophenol, sodium dodecylsulfate, hydroquinone, and citric acid-which were deemed to be representative and had been investigated in several previous studies, were used as photodegradation targets. However, it was not possible to obtain a direct expression of "catalytic efficiency" simply by reading the data obtained, nor any indirect molecular "recalcitrancy" scale. Chemometric analysis, by principal components analysis, allows the five used catalytic systems to be easily compared each other and a single PC component is able to perform classification.

Journal Article↗

PubMed2001

The use of alternative technologies to develop malolactic fermentation in wine.

The development of the malolactic fermentation, bioconversion of L-malic acid to L-lactic acid, is a difficult and time-consuming process that does not always proceed favorably under the natural conditions of wine. Traditional fermentations are used worldwide to produce high-quality wines, although delay or failure is not an unusual outcome. During recent years several technologies have been proposed to induce biological deacidification of wines by using malolactic bacteria, principally Oenococcus oeni and Lactobacillus sp. These alternative technologies usually involve the use of high densities of cells or enzymes, free or immobilized onto different matrices. Immobilization materials, several types of bioreactors, and the properties of many specific systems are discussed in this review.

Biomass↗

PubMed2003

Enzymatic browning and biochemical alterations in black spots of pineapple [Ananas comosus (L.) Merr.].

Penicillium funiculosum Thom. was consistently isolated from pineapple-infected fruitlet (black spots). Polyphenol oxidase, peroxidase, and laccase activities were determined in extracts from contiguous and infected fruitlets. Healthy fruitlets showed a rather high level of polyphenol oxidase (optimum pH 7.0), and this activity was tremendously increased (X 10) in contiguous infected fruitlets. Furthermore, infected fruitlets also exhibited laccase activity (optimum pH 4.0), while peroxidase was rather constant in both fruitlets. Browning reactions were attributed to qualitative and quantitative modifications of the enzymatic equipment (polyphenol oxidase and laccase) (p < 0.0001). In infected fruiltets, sucrose and L-malic acid were present at significantly lower amounts than in healthy ones, likely owing to fungal metabolism (p < 0.0001), whereas cell wall material was three times higher, which could be viewed as a defense mechanism to limit expansion of the mycelium.

Ananas↗

PubMed2005

Putrescine accumulation in wine: role of Oenococcus oeni.

Putrescine, the most abundant biogenic amine in wine, was proved to be produced by Oenococcus oeni strains in wine not only from ornithine but also from arginine. In this case, putrescine may originate from strains possessing the complete enzyme system to convert arginine to putrescine or by a metabiotic association, with an exchange of ornithine, between strains capable of metabolizing arginine to ornithine but unable to produce putrescine and strains capable of producing putrescine from ornithine but unable to degrade arginine. Putrescine production by this metabiotic association occurred once the malolactic fermentation was completed, whereas conversion of ornithine to putrescine by a single culture of the ornithine decarboxylating strain concurred with the degradation of malic acid. Moreover, in the former case, putrescine formation proceeded more slowly than in the latter. Metabiosis may play an important role in the accumulation of putrescine in wine, arginine being one of the major amino acids found in wine.

Gram-Positive Cocci↗

PubMed2006

Characterization of the chromophores of pyoverdins and related siderophores by electrospray tandem mass spectrometry.

Characteristic fragment ions of the various chromophores of the pyoverdin siderophore family obtained by collision activated dissociation of the [M+2H]2+ ions are reported allowing unambiguous identification. Tandem mass spectrometrical studies revealed the existence of the first example of a ferribactin with a succinamide side chain, and they add some information to the problem in which way a malic acid side chain is attached to the chromophore.

Amino Acid Sequence↗

PubMed1990

Native agarose-polyacrylamide gel electrophoresis allowing the detection of aminopeptidase, dehydrogenase, and esterase activities at the nanogram level: enzymatic patterns in some Frankia strains.

Nanogram amounts of soluble aminopeptidases, dehydrogenases, and esterases were detected by nondenaturing ultralow gelling point agarose-polyacrylamide gel electrophoresis (ULGA-PAGE). Cytosolic fractions from Frankia sp. were electrophoresed at 4 degrees C in the presence of Co2+, Zn2+, or Mg2+ ions. Then, aminopeptidases and esterases were revealed by simultaneous capture staining by using fast garnet GBC diazonium salt as the chromogenic coupling compound. Dehydrogenases were revealed by using nitro blue tetrazolium salt as electron acceptor. A variety of aminopeptidases, dehydrogenases, and esterases could be identified by their migration in ULGA-PAGE and by their sensitivities to NaCl, CoSO4, ZnSO4, and MgCl2 when assayed "ingel." The presence of agarose was essential for the detection of the complex enzyme patterns. The patterns were remarkably similar for the five Frankia strains isolated from Allocasuarina and Casuarina host plants and differed from those of Frankia strains isolated from Comptonia and Hippophaë host plants. A nomenclature is proposed for aminopeptidases and other Frankia enzymes. The richness of the Frankia amino-peptidases and esterases zymograms makes them adequate marker enzymes for taxonomical, genetic, or biochemical studies. Dehydrogenases might also be useful, although a more restricted number of bands were found with L-lactic and L-malic acid as substrates.

Actinomyces↗

PubMed1970

Les polyglycerophospholipides d'Euglena gracilis.

In light or dark grown Euglena gracilis cells, the DPG content, in contrast to the PG content, is dependent on the carbon source. These results are closely related to the electron microscopy observations, showing structural changes in mitochondria varying with the carbon source of the media.Two media have been used: the first one contains L-glutamic and DL-malic acid and the second contains DL-lactic acid. The phospholipidic analysis shows that PC and PE are the two main phospholipids.

Journal Article↗

PubMed1993

Antimicrobial and antioxidant activities of unripe papaya.

The meat, seed and pulp of Carica papaya Linn., a popular traditional medicinal herb grown in the tropics, was shown by the agar-cup method to be bacteriostatic against several enteropathogens such as Bacillus subtilis, Enterobacter cloacae, Escherichia coli, Salmonella typhi, Staphylococcus aureus, Proteus vulgaris, Pseudomonas aeruginosa, and Klebsiella pneumoniae. The same parts of papaya were unequivocably demonstrated by electron spin resonance spectrometry to scavenge 1,1-diphenyl-2-picrylhydrazyl (5.8 x 10(14) spins/ml), hydroxyl (5.1 x 10(14) spins/ml) and superoxide (1.2 x 10(14) spins/ml) radicals with the seed giving the highest activity at concentrations (IC50) of 2.1, 10.0 and 8.7 mg/ml, respectively. The superoxide dismutase (SOD)-like activity in the meat, seed and pulp amounts to about 32, 98 and 33 units/ml; comparable to those of soybean paste miso, rice bran and baker's yeast. Vitamin C, malic acid, citric acid and glucose are some of the possible antioxidative components in papaya. Our study correlates the bacteriostatic activity of papaya with its scavenging action on superoxide and hydroxyl radicals which could be part of the cellular metabolism of such enteropathogens. This is indicative of the pathophysiological role of these reactive oxygen species in gastrointestinal diseases and papaya's ability to counteract the oxidative stress.

Anti-Bacterial Agents↗

PubMed1988

Attenuation of neophobia and conditioned taste aversion in the rabbit.

The phenomenon of taste neophobia to apple juice does exist in the rabbit. It was found that malic acid was the main stimulus source. Attenuation of taste neophobia was due to neuronal processes which took place between rather than during drinking sessions. Conditioned taste aversion learning took place if apomorphine was injected after apple juice intake.

Animals↗

PubMed1983

Cytosolic malate dehydrogenase in muscle extracts of Toxocara canis.

1. Malate dehydrogenase (L-malic acid:NAD+ oxydoreductase, EC 1.1.1.37) was partially purified from muscle extracts of Toxocara canis by means of gel chromatography in Sephadex G-150 and affinity chromatography in Sepharose-4B-Blue dextran. 2. The purified enzyme was very active in reducing oxalacetate and less active in oxidizing L-malate. It was inhibited by excess oxalacetate but not by L-malate. 3. The kinetic parameters of the enzyme were obtained and these included: pH and temperature optima and apparent Michaelis constants for the substrates. 4. The results suggest that the enzyme from Toxocara canis behaves like the enzyme of the model helminth Ascaris lumbricoides.

Animals↗

PubMed1987

Agarose gel electrophoresis of human erythrocyte glutamic-pyruvic transaminase (GPT EC 2.6.1.2).

The method of choice to determine erythrocyte glutamate-pyruvic transaminase (GPT) including rare variants was starch gel electrophoresis. Methods using agarose as gel medium were not reported to our knowledge. We present an adapted method using the Tris/maleate buffer system and an agarose of low endosmosis. The common as well as rare variant types of GPT were quickly and reliably separated. In addition, a method for the consecutive determination of esterase D (ESD) and GPT on the same gel using the malic acid buffer system is described.

Alanine Transaminase↗

PubMed1994

L-carnitine via enzyme-catalyzed oxidative kinetic resolution.

L-Carnitine of high optical purity was prepared via kinetic resolution using a mutant strain of Acinetobacter calcoaceticus ATCC 39647. This organism preferentially metabolized the D-enantiomer of the racemate to furnish L-carnitine. Recovery of L-carnitine was 93%, providing a total weight yield of 46.5% in 92% enantiomeric excess. The mode of degradation of carnitine was shown to proceed via a monooxygenase-catalyzed oxidative cleavage resulting in the formation of trimethylamine and malic acid. The data suggest that the stereoselective metabolism of DL-carnitine is probably the result of differential permeability of the cell membrane towards the optical antipodes.

Acinetobacter calcoaceticus↗

PubMed1996

(R-Z)-7,15-hexadecadien-4-olide, sex pheromone of the yellowish elongate chafer, Heptophylla picea.

An active component of the sex pheromone system of the yellowish elongate chafer, Heptophylla picea was identified by GC-EAD. Mass spectral data and hydrogenation revealed that the active compound was a hexadecadien-4-olide. It was not possible to determine the double bond positions by direct DMDS derivatization of the pheromone, but partial hydrogenation (diimide) followed by DMDS derivatization showed that the double bonds were located in positions 7 and 15. FTIR (tracer) of the pheromone corroborated the lactone structure (1772 cm-1) and showed a band characteristic of a terminal double bond at 3073 cm-1, and one of a double bond in the cis-configuration at 3002 cm-1. Chiral resolution of the pheromone, after hydrogenation, demonstrated that the natural lactone had the (R)-stereochemistry. Synthetic (R,Z)-7,15-hexadecadien-4-olide, prepared from L-malic acid in 14 steps, was identical to the natural product in MS, IR, retention times and biological activity. This is the first fatty acid derivative compound found as a sex pheromone of a Melolonthinae species and as far as biosynthesis is concerned this is the most complex pheromone constituent of a scarab species.

4-Butyrolactone↗

PubMed2006

A practical synthesis of the major 3-hydroxy-2-pyrrolidinone metabolite of a potent CDK2/cyclin A inhibitor.

The synthesis of the major metabolite of a potent 3-aminopyrazole CDK2/cyclin A inhibitor is presented. A stereoconservative approach starting from malic acid was employed to construct the hydroxy-substituted pyrrolidinone moiety. In the key step of the synthesis the use of cyanoborohydride immobilized on Amberlyst 26 in trifluoroethanol represented a valid alternative to conventional solution-phase reducing agents.

Animals↗

PubMed2005

The structure of the O-polysaccharide of the Pseudoalteromonas rubra ATCC 29570T lipopolysaccharide containing a keto sugar.

The structure of the phenol-soluble polysaccharide from Pseudoalteromonas rubra type strain ATCC 29570T has been elucidated using 1H and 13C NMR spectroscopy, including 2D COSY, TOCSY, gNOESY, ROESY, 1H,13C gHMQC and gHMBC experiments. It is concluded that the trisaccharide repeating unit of the polysaccharide has the following structure: [carbohydrate structure: see text] where Sug is 2-acetamido-2,6-dideoxy-D-xylo-hexos-4-ulose, Am is acetimidoyl and Acyl is a malic acid residue, which is O-acetylated in approximately 70% of the units.

Carbohydrate Sequence↗