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PubMed2000

Characterization of Microbial Consortia in Paddy Rice Soil by Phospholipid Analysis.

Microbial biomass and community structure in paddy rice soil during the vegetation period of rice were estimated by analysis of their phospholipid fatty acids (PLFA), hydroxy fatty acids of lipopolysaccharides (LPS-HYFA), and phospholipid ether lipids (PLEL) directly extracted from the soil. A clear change in the composition of the community structure at different sampling periods was observed, indicated by the principal component analysis of the PLFA. A dramatic decline of ester-linked PLFA was observed in the soil samples taken at the second sampling time. In contrast to the ester-linked PLFA, the non-ester-linked PLFA composition did not change. The hydroxy fatty acids of lipopolysaccharides as well as ether lipids decreased consecutively during the observation period. Total microbial abundance was estimated to be (4.1-7.3) x 10(9) cells g(-1) soil (dry weight). About 44% account for aerobic and 32% for facultative anaerobic bacteria, and 24% for archaea, on average. According to the profile and patterns of PLFA in the soil sample, it may be suggested that the paddy soil at the August sampling period contained more abundant facultative anaerobic bacteria (ca. 36%) and archaea (ca. 37%), but the total microbial biomass was significantly lower than in the remaining sampling periods. As the plant approached maturity, the microbial community structure in the soil changed to contain more abundant Gram-negative bacteria and methanotrophs.

Journal Article↗
PubMed2006

SUCI02 inhibits the erbB-2 tyrosine kinase receptor signaling pathway and arrests the cell cycle in G1 phase in breast cancer cells.

The erbB-2 gene encodes tyrosine kinase receptor p185(neu). Overexpression of erbB-2 plays a key role in tumorigenesis and the progression of tumors such as breast cancer and ovarian cancer. Our investigation suggests that the anti-inflammatory agent N-(4-ethoxyphenol)-2-hydroxy-acid amide (SUCI02) reversibly represses tyrosine phosphorylation of erbB-2 in a dose-dependent manner, with half maximal inhibition occurring at a concentration of 21.05 micromol/L without reduced erbB-2 receptor expression. Activation of mitogen-activated protein kinase and protein kinase B, downstream molecules of the erbB-2-mediated signal transduction pathway, was inhibited following exposure to SUCI02. In contrast, tyrosine phosphorylation of epidermal growth factor receptor (EGFR) was relatively unaffected by SUCI02. Proliferation of erbB-2-overexpressing BT474 cells was inhibited to a greater extent than proliferation of EGFR-overexpressing A431 cells following exposure to SUCI02. SUCI02 induced cell cycle arrest in G(1) phase with upregulation of p27 and downregulation of pRb phosphorylation. Systemic administration of SUCI02 in nude mice resulted in inhibition of erbB-2 tyrosine kinase phosphorylation of subcutaneous human breast cancer BT474 xenografts. We conclude that SUCI02 inhibits erbB-2 tyrosine kinase phosphorylation in vitro and in vivo, shuts down the erbB-2 downstream pathway and induces cell cycle arrest in G(1) phase. These results suggest that SUCI02 is a potential novel anticancer agent that deserves further investigation. (Cancer Sci 2006; 97: 84-89).

Amides↗
PubMed2003

[SUCI02 inhibits HER-2/neu receptor tyrosine kinase phosphorylation and growth of HER-2/neu-overexpressing breast cancer cells].

BACKGROUND & OBJECTIVE: Overexpression of HER-2/neu receptor plays a key role in tumorigenesis,progression,prognosis and chemosensitivity of tumors. We found that SUCI02[N-(4-ethoyphenol)-2-hydroxy- acid amide] could inhibit HER2/neu phosphorylation through comprehensive screening. The aim of this study was to examine the effect of SUCI02 on HER-2/neu-overexpressing cancer cell growth. METHODS: Western blot analysis and immunoprecipitation was used to examine the changes of HER-2/neu receptor tyrosine kinase phosphorylation and protein level. MTT assay was employed to determine the growth inhibition of SUCI02 on the tumor cells. RESULTS: SUCI02 reversibly inhibited tyrosine phosphorylation of HER-2/neu in a dose-dependent manner with half maximal inhibition at a concentration of 4.34 microg/ml without reduced HER-2/neu receptor protein expression. Activation of MAPK and AKT, which were downstream molecules of HER-2/neu-mediated signal transduction pathway, was inhibited after being exposure to SUCI02. In contrast, tyrosine phosphorylation of EGFR was relatively unaffected at the concentrations of SUCI02 up to 40 microg/ml. SUCI02 inhibited cell proliferation of HER-2/neu- overexpressing MDA-MB-453m1 more potent than that of EGFR-overexpressing MDA-MB-468.Their IC(50) values were 1.33 microg/ml and 11.3 microg/ml,respectively. CONCLUSION: SUCI02 can inhibit tyrosine phosphorylation of HER-2/neu receptor,cell proliferation of HER-2/neu-overexpressing breast cancer cells preferentially and shut down downstream HER-2/neu signal transduction.

Amides↗
PubMed2006

Quantitative determination of the main aliphatic carboxylic acids in wood kraft black liquors by high-performance liquid chromatography-mass spectrometry.

The versatile characterization of organic material and especially of the significant aliphatic hydroxy acids in black liquor is of great importance, for example, in monitoring the progress of the kraft pulping process. This paper describes a simple high-performance liquid chromatographic separation method with atmospheric-pressure chemical ionization mass spectrometry (HPLC-APCI-MS) which was developed for the rapid quantitative analysis of these acids, mainly formed as the alkaline degradation products of feedstock carbohydrates. The fraction of carbohydrate degradation products is mainly composed of hydroxy monocarboxylic and volatile acids (formic and acetic acids) along with lesser amounts of various dicarboxylic acids. This method was thoroughly tested and validated to determine the most abundant nonvolatile low-molecular-mass aliphatic mono- and dicarboxylic acids present in softwood (pine and spruce) and hardwood (birch and aspen) kraft black liquors. This straightforward technique provides, compared to the conventional gas chromatographic methods, some important advantages such as simple sample preparation and a faster analysis time, thus enabling almost real-time monitoring of these acids.

Carboxylic Acids↗
PubMedDate not supplied

Studies on the beta-oxidation of valproic acid in rat liver mitochondrial preparations.

Incubation of valproic acid (VPA) with freshly isolated rat liver mitochondria led to the identification of the beta-keto acid, 3-oxo-VPA, together with three unsaturated metabolites, viz. delta 2(E)-VPA, delta 3-VPA, and delta 2(E),3'(E)-VPA. The corresponding beta-hydroxy acid, 3-hydroxy-VPA, was not detected as a metabolite of VPA in this in vitro system. Studies with subcellular fractions of rat liver and with inhibitors of fatty acid metabolism demonstrated that these metabolites are products of the beta-oxidation system in mitochondria, and are not formed to any significant extent by the related peroxisomal beta-oxidation complex. When incubations with mitochondria were carried out in a medium enriched in H218O, metabolites were labeled in a manner consistent with the involvement of coenzyme A thioester intermediates. Incubation of the authentic metabolites with mitochondrial preparations showed that delta 2(E)-VPA, delta 3-VPA, and delta 2(E),3'(E)-VPA are interconverted by isomerization and reduction processes, and that all three serve as precursors of 3-oxo-VPA. It is concluded that VPA is a substrate for beta-oxidation in liver mitochondria, and that competition by VPA for enzymes and/or cofactors of the fatty acid beta-oxidation complex may contribute to VPA-mediated inhibition of fatty acid metabolism and associated hepatic steatosis.

Animals↗
PubMed1985

Identification of felodipine metabolites in rat urine.

After intragastric administration of 100 mumol kg-1 [14C]felodipine to rats eight urinary metabolites were isolated. Batch extraction at pH 2.2 and semipreparative reversed-phase liquid chromatography were used for trace enrichment of the metabolites. Trimethylsilylation followed by transesterification with diazomethane blocked the carboxylic acid and alcohol groups selectively before gas chromatography/mass spectrometry (GC/MS) in the electron impact (EI) mode. Deuterated derivatives of the metabolites and chemical ionization measurements added complementary structural information. All metabolites reported in this study were formed from oxidized felodipine by ester hydrolysis. Hydroxylation of the pyridine methyl group represented an important metabolic pathway and metabolites oxidized to the corresponding carboxylic acids were detected as well. Lactone formation from hydroxy acid metabolites in urine as a possible analytical artefact is discussed.

Animals↗
PubMed1994

Intermediate metabolism in Trypanosoma cruzi.

Epimastigotes of Trypanosoma cruzi, the causative agent of Chagas disease, catabolize proteins and amino acids with production of MH3, and glucose with production of reduced catabolites, chiefly succinate and L-alanine, even under aerobic conditions. This "aerobic fermentation of glucose" is probably due to both the presence of low levels of some cytochromes, causing a relative inefficiency of the respiratory chain for NADH, reoxidation during active glucose catabolism, and the lack of NADH dehydrogenase and phosphorylation site I, resulting in the entry of reduction equivalents into the chain mostly as succinate. Phosphoenol pyruvate carboxykinase and pyruvate kinase may play an essential role in diverting glucose carbon to succinate or L-alanine, and L-malate seems to be the major metabolite for the transport of glucose carbon and reduction equivalents between glycosome and mitochondrion. The parasite contains proteinase and peptidase activities. The major lysosomal cysteine proteinase, cruzipain, has been characterized in considerable detail, and might be involved in the host/parasite relationship, in addition to its obvious role in parasite nutrition. Among the enzymes of amino acid catabolism, two glutamate dehydrogenases (one NADP- and the other NAD-linked), alanine aminotransferase, and the major enzymes of aromatic amino acid catabolism (tyrosine aminotransferase and aromatic alpha-hydroxy acid dehydrogenase), have been characterized and proposed to be involved in the reoxidation of glycolytic NADH.

Aerobiosis↗
PubMed1995

Lipopolysaccharide determination by reversed-phase high-performance liquid chromatography after fluorescence labeling.

A sensitive method for the quantitative determination of lipid A, the covalently bound hydrophobic component of lipopolysaccharides (endotoxins), has been developed. The determination of lipid A was based on the quantitative measurement of beta-hydroxymyristic acid and beta-hydroxylauric acid by reversed-phase HPLC. beta-Hydroxy acids were liberated from ester and amide linkages in endotoxins by acid catalyzed methanolysis. The resulting methyl esters were derivatized with 9-anthracene-carboxyl chloride, 9-fluorene-carboxyl chloride and 4-(1-pyrenyl)butyric acid chloride and quantified with a fluorescence detector. The effectiveness of the three derivatizing agents was compared. As internal standards-beta-hydroxytridecanoic acid [beta-OH(13:0)] and beta-hydroxypentadecanoic acid [beta-OH(15:0)] ethyl esters were used. The limits of detection of beta-hydroxymyristic acid were 0.5 pg for the 9-anthroyl and 2 pg for the fluorenoyl and 4-(1-pyrenyl)butyroyl ester per sample (signal-to-noise ratio of 3). The detection limits of lipopolysaccharide from a smooth strain (Escherichia coli 0111:B4) was 20 pg, while that from two rough strains (E. coli Nissle 1917 and Salmonella typhimurium SL 1181) was 5 pg per sample after methanolysis and derivatization with 9-anthroyl chloride.

Chromatography, High Pressure Liquid↗
PubMed2002

Biochemical and molecular properties of the cytochrome P450 arachidonic acid monooxygenases.

The cytochrome P450 (P450) arachidonic acid (AA) monooxygenase metabolizes the fatty acid to a series of epoxy- and hydroxy-acid derivatives. Catalytic turnover requires NADPH, and requires the redox-coupled activation and cleavage of diatomic oxygen, and the delivery of an active form of atomic oxygen to ground state carbon atoms. Past and present advances in P450 biochemistry and molecular biology are beginning to provide a description of the P450 isoform specificity of AA bioactivation, and the mechanisms of action and physiological relevance of the P450 metabolites. The demonstration of the endogenous biosynthesis of many of these metabolites has established the P450 pathway as an important route for AA bioactivation, and has begun to uncovered new and important functional roles for this enzyme system in cell and organ physiology.

Animals↗
PubMed1997

Simple approach for analysis of plasma oxo-, hydroxy- and dicarboxylic acids.

Following deproteinization of plasma with organic solvents the supernatant was shaken with hexane and cation-exchange resin in an Eppendorf tube to remove fatty and amino acids and the medium was subjected to direct treatment with ethyl chloroformate under catalytic influence of pyridine. A subsequent extraction of the immediately formed ethyl esters with a drop of chloroform enabled us to subject the sample to gas chromatographic (GC) analysis. Since ketocarboxylic acids do not require a preliminary oximation the total time of sample workup and analysis takes only several minutes.

Chromatography, Gas↗
PubMed1999

Novel glycoinositolphosphosphingolipids, basidiolipids, from Agaricus.

From the edible mushroom, the basidiomycetes Agaricus bisporus and Agaricus campestris, a novel carbohydrate-homologous series of four glyco-inositol-phospho-sphingolipids, designated basidiolipids, was isolated and the constituents purified. The chemical structures of the basidiolipids were elucidated to be: Manpbeta1-2inositol1-phospho-ceramide, Galpalpha-6[Fucpalpha-2]Galpbeta-6Manpbeta-2i nositol1-phospho-ceramide, Galpalpha-6Galpalpha-6[Fucpalpha-2]Galpbeta- 6Manpbeta-2inositol1-phospho-ceramide and Galpalpha-6Galpalpha-6Galpalpha-6[Fucpalpha-2] Galpbeta-6Manpbeta-2ino sitol1-phospho-ceramide. All four glycolipids contained a ceramide which was composed of phytosphingosine and predominantly alpha-hydroxy-behenic and alpha-hydroxy-lignoceric acid.

Adjuvants, Immunologic↗
PubMed1981

Induction of urea cycle enzymes of rat liver by amino acids.

To determine which amino acids in a high casein diet are responsible for induction of the five urea cycle enzyme activities in rat liver, we tube-fed 21 L-amino acids singly to rats over 2 days at maximum doses which did not cause toxicity. The results were compared with the 1.3- to 1.9-fold increases (units/100 g rat) obtained by tube-feeding 2 g N/kg for 2 days as casein hydrolysate. Ala (2 g N/kg), Gly /2 g N/kg), Met (0.2--0.4 g N/kg) and Cys (0.4 g N/kg) were the only amino acids which increased all five activities. Moreover, Met. Ala, Gly and casein hydrolysate in these doses increased immuno-precipitable arginase as much as they increased its activity. A combination of Met, Ala and Gly (2 g N/kg) increased all five activities more than 2 g N/kg of casein hydrolysate. Met (0.05 g N/kg) + Ala (0.08 g N/kg) + Gly (0.1 g N/kg), the amounts of these contained in 2 g N/kg of casein, increased all five enzymes in 2 days as much as this dose of casein hydrolysate. Met (0.06 g N/kg) alone increased all five activities (units/100 g rat) 1.2 to 1.4-fold over controls by increasing g liver/100 g rat. Ammonium citrate or acetate tube-feedings over 8 days at 2 g N/kg increased only AS. The keto-acid of alanine, pyruvate, or the alpha-hydroxy acid of methionine did not increase any enzyme whereas the same molar dose of their amino acids increased all five activities. Thus three amino acids of casein, Ala, Gly and especially Met, account for the enzyme adaptation of the urea cycle on a high casein diet.

Alanine↗
PubMed2003

Cooperation between Lactococcus lactis and nonstarter lactobacilli in the formation of cheese aroma from amino acids.

In Gouda and Cheddar type cheeses the amino acid conversion to aroma compounds, which is a major process for aroma formation, is essentially due to lactic acid bacteria (LAB). In order to evaluate the respective role of starter and nonstarter LAB and their interactions in cheese flavor formation, we compared the catabolism of phenylalanine, leucine, and methionine by single strains and strain mixtures of Lactococcus lactis subsp. cremoris NCDO763 and three mesophilic lactobacilli. Amino acid catabolism was studied in vitro at pH 5.5, by using radiolabeled amino acids as tracers. In the presence of alpha-ketoglutarate, which is essential for amino acid transamination, the lactobacillus strains degraded less amino acids than L. lactis subsp. cremoris NCDO763, and produced mainly nonaromatic metabolites. L. lactis subsp. cremoris NCDO763 produced mainly the carboxylic acids, which are important compounds for cheese aroma. However, in the reaction mixture containing glutamate, only two lactobacillus strains degraded amino acids significantly. This was due to their glutamate dehydrogenase (GDH) activity, which produced alpha-ketoglutarate from glutamate. The combination of each of the GDH-positive lactobacilli with L. lactis subsp. cremoris NCDO763 had a beneficial effect on the aroma formation. Lactobacilli initiated the conversion of amino acids by transforming them mainly to keto and hydroxy acids, which subsequently were converted to carboxylic acids by the Lactococcus strain. Therefore, we think that such cooperation between starter L. lactis and GDH-positive lactobacilli can stimulate flavor development in cheese.

Amino Acids↗
PubMed2001

Redox enzymes used in chiral syntheses coupled to coenzyme regeneration.

Due to their ability to perform reactions in a stereo- and regiospecific manner, while functioning under mild conditions of temperature and pH, enzymes are increasingly used for chiral synthesis in the pharmaceutical industry, in medicinal chemistry, agriculture, cosmetic and food industry. The oxidoreductases as catalysts require a coenzyme (cofactor) which functions as an electron carrier. If used in stoichiometric amounts the cost of coenzymes makes synthetic applications of redox enzymes prohibitively expensive for industrial applications. The present review updates previous discussions about the objectives of cofactor regeneration as a requirement for the applicability of enzymatic redox reactions, and about the strategies customarily used to this end. Different types of chiral syntheses coupled successfully to coenzyme regeneration (amino acid synthesis, lactone synthesis, synthetic reactions involving alcohols, hydroxy acid and steroid synthesis, deracemization) are then discussed. New catalysts, cross-linked enzyme crystals, prepared from redox enzyme are presented in a small paragraph together with some of their applications. Special attention is given to whole cells used in this type of synthesis and their advantages and disadvantages are presented in one paragraph. Finally, different reactors, within which were conducted chiral syntheses catalyzed by oxireductases and coupled to cofactor regeneration, are briefly discussed.

Coenzymes↗
PubMed2001

A family of depsi-peptide fungal metabolites, as selective and competitive human tachykinin receptor (NK2) antagonists: fermentation, isolation, physico-chemical properties, and biological activity.

Four tachykinin (NK2) receptor inhibitors, SCH 378161 (1), SCH 217048 (2), SCH 378199 (3), and SCH 378167 (4) were isolated from the fermentation broth of a taxonomically unidentified fungus. These compounds were separated from the fermentation broth by ethyl acetate extraction. Purification and separation of the individual compounds were achieved by NK2 assay-guided fractionation using gel filtration, reverse phase chromatography and HPLC. They were identified to be a family of depsipeptides by spectroscopic and degradation studies. Compounds 1 and 3 contain proline and differ as an amide and acid whereas 2 and 4 contain pipecolic acid and differ in being an amide and acid. All of these compounds contain an identical hydroxy acid. They are selective NK2 inhibitors with Ki values ranging from 27-982 nM and demonstrate no activity at 10 microM in the NK1 and NK3 assays. In addition, compounds 1 and 2 inhibited NKA-induced increases in the concentration of intracellular Ca2+, [Ca2+]i, in a CHO cell expressing the human NK2 receptor; this inhibition was competitive in nature with pA2 values of 7.2 and 7.5, respectively. These data demonstrate that these natural products are selective and competitive receptor antagonists of the human NK2 receptor.

Animals↗
PubMed1988

Inhibition of cell migrations by the linoleic acid oxygenation product 9S-hydroxy 10E,12Z octadecadienoic acid (9-HODE).

The linoleic acid metabolite 9S-HODE was prepared by means of tomato fruit lipoxygenase and purified by high-performance liquid chromatography (HPLC) to a high steric purity as judged by chiral-phase HPLC. 9S-HODE caused in the concentration range between 0.01 and 1 microM a strong dose-dependent inhibition of the migration of both cultured porcine aortic endothelial cells and of phytohaemagglutinin-stimulated human mononuclear cells. The effect was not observed with another polyenoic fatty acid metabolite, 15S-hydroperoxy-5Z,8Z,11Z,13E-eicosatetraenoic acid (15-HPETE). The results are discussed in the light of other biological actions of 9-HODE recently described.

Animals↗