Search Results
Results 401 - 450 of 1091
< 4 5 6 7 8 9 10 11 12 13 14 >
Lee K B - - 1998
Chondroitin sulfates were isolated from the mud snail. For the quantitative analysis of enzymatic digestion products of isolated chondroitin sulfates, strong anion exchange-high performance liquid chromatography (SAX-HPLC) was performed. By the action of chondroitinase ABC, three unsaturated disaccharides 2-acetamide-2-deoxy-3-O-(beta-D-gluco-4-enepyranosyluronic acid)-D-galactose (delta Di-OS), 2-acetamide-2-deoxy-3-O-(beta-D-gluco-4-enepyranosyluronic acid)-6-O-sulfo-D-galactose (delta Di-6S) and 2-acetamide-2-deoxy-3-O-(beta-D-gluco-4-enepyranosyluronic acid)-4-O-sulfo-D-galactose (delta ...
Corso T N - - 1998
Carbon in derivatization groups cannot be distinguished from analyte carbon by chromatography-based high-precision compound-specific or position-specific isotope analysis. We report the reduction of fatty acid methyl esters to fatty alcohols to facilitate high-quality chromatographic separation, without addition of extraneous carbon, with subsequent high-precision position-specific isotope analysis. Methyl palmitate is quantitatively ...
Osterhout G J - - 1998
CDC group IVc-2 is a gram-negative, oxidase-positive, nonfermentative bacillus that has been implicated in human infections, including septicemia and peritonitis. Biochemically it most closely resembles Bordetella bronchiseptica and Alcaligenes sp. Results of cellular fatty acid (CFA) and 16S rRNA gene analysis were combined with biochemical data to assist in identification ...
Caballero F A - - 1998
1. The effect of in vitro glycation on delta-aminolevulinic dehydratase (ALA-D) under several experimental conditions was investigated. When preincubated with 500 mM glucose at 37 degrees C for 20 hr, ALA-D was 80% inactivated and glycated hemoglobin levels were increased more than fourfold. 2. Thiobarbituric acid species were not modified ...
Fritsch C - - 1998
Topically applied delta-aminolevulinic acid is used efficiently for the treatment of solar keratoses by photodynamic therapy. Recent animal studies suggest that porphyrin sensitization of epithelial tissue is improved by using esters rather than free delta-aminolevulinic acid. The present study examines porphyrin metabolite formation after topical application of delta-aminolevulinic acid or ...
Brooks B - - 1998
Versions of the Y55F/Y88F modified form of Delta 5-3-ketosteroid isomerase in which the active-site tyrosine-14 is replaced by 2-fluorotyrosine, 3-fluorotyrosine, and 2,3-difluorotyrosine, amino acids having progressively greater acidity of their phenolic hydroxyls, have been expressed in an Escherichia coli host and purified to high homogeneity. The steady-state kinetic properties of ...
Princ F G - - 1998
1. delta-Aminolevulinic acid (ALA) has been reported to promote reactive oxygen species (ROS). Overproduction and accumulation of ALA, as it occurs in acute intermittent porphyria (AIP), can be the origin of an endogenous source of ROS, which can then exert their oxidative damage to cell structures. 2. To investigate the ...
Yamada S - - 1998
A novel disaccharide was isolated beside the predominant trisulfated disaccharide, delta HexA(2-O-sulfate)(alpha 1-4)GlcN(2-N-,6-O-disulfate) (delta HexA and GlcN represent 4-deoxy-alpha-L-threo-hex-4-enepyranosyluronic acid and D-glucosamine, respectively) after treatment of porcine intestinal heparin with Flavobacterium heparinase. It accounted for 18% of total disaccharides. The structure was characterized by secondary ion mass spectrometry, enzymatic digestions, ...
Williams J - - 1998
cDNA corresponding to the GA4 gene of Arabidopsis thaliana L. (Heynh. ) was expressed in Escherichia coli, from which cell lysates converted [14C]gibberellin (GA)9 and [14C]GA20 to radiolabeled GA4 and GA1, respectively, thereby confirming that GA4 encodes a GA 3beta-hydroxylase. GA9 was the preferred substrate, with a Michaelis value of ...
Sarmini K - - 1998
The change in the pKa values of substituted benzoic acids in binary mixtures of water with N,N-dimethylformamide (DMF) and N,N-dimethylacetamide (DMA), respectively, was determined up to a concentration of 80% (vol/vol) organic cosolvent. Such solvents are applied as media of the background electrolyte in capillary electrophoresis, with the intention of ...
Woodbury S E - - 1998
The delta 13C values of the major fatty acids of several different commercially important vegetable oils were measured by gas chromatography--combustion--isotope ratio mass spectrometry. The delta 13C values obtained were found to fall into two distinct groups, representing the C3 and C4 plants classes from which the oils were derived. ...
Merényi G - - 1998
The rate constant of homolysis of peroxynitrite, ONOO-, into O2- and NO was determined to be 0.017 s-1 at 20 degrees C. In combination with other experimental data taken from the literature, this value yields the Gibbs free energy of formation of ONOO-, delta f G o(ONOO-) = 16.6 kcal/mol. ...
Zubiaur J - - 1998
The protolytic behavior of d-gluconic-delta-lactone acid has been studied by means of automated potentiometric titrations at different ionic strengths in the range 0.1</=I</=3.0 mol dm(-3) in NaClO(4) at 25 degrees C. This study reveals a protolytic equilibrium of gluconic acid as well as a distribution equilibrium between gluconic acid (HG) ...
Iwase T - - 1998
OBJECTIVE: Biochemical aspects of the etiology of articular cartilage degeneration in osteonecrosis of the femoral head have not been investigated extensively. We analyzed biochemical conditions in the hip joint cavity, regarding articular cartilage turnover in osteonecrosis of the femoral head (ONFH). METHODS: Cartilage metabolism markers in synovial fluid were measured. ...
Bonetti S J - - 1998
Filtrates of heat (54 degrees) treated day-5 Penicillium fellutanum cultures contained 70 mg of peptidophosphogalactomannan-II; an unheated control contained 30 mg. The polymer contained up to 60 phosphodiesters, and 5-O-beta-D-galactofuranosyl, mannopyranosyl, amino acyl and 2-aminoethanol residues. Its 13C NMR spectrum was nearly identical with that of the control polymer. The ...
Aggelis G - - 1998
Aqueous Teucrium polium extract slightly inhibits the growth of Saccharomyces cerevisiae (Ki = 0.029 [g/l]-1) and Yarrovia lipolytica (Ki = 0.06l [g/l]-1). However, this extract causes important changes in the unsaturation degree (delta/mol) of the cellular lipids. It moreover favours the increase of the linolenic acid concentration and the decrease ...
Grandgirard A - - 1998
The isomerization of linolenic acid into mono- and di-trans isomers takes place during heat treatment. One of these compounds, 18:3 delta 9c, 12c, 15t can be desaturated and elongated to form, in particular, the trans isomers of eicosapentaenoic and docosahexaenoic acids. This study was undertaken to observe the incorporation of ...
Carneiro R C - - 1998
The in vitro and in vivo effect of melatonin on delta-aminolevulinic acid-induced lipid peroxidation in rat cerebellum, cortex and hippocampus was determined. The concentration of malonaldehyde and 4-hydroxyalkenals was assayed as an index of induced membrane oxidative damage. The rise in malonaldehyde+4-hydroxyalkenals concentrations induced by delta-aminolevulinic acid in cerebellar homogenates ...
Sassa S - - 1998
ALAD porphyria is an autosomal recessive disorder resulting from a homozygous aminolevulinic acid dehydratase (ALAD) deficiency. Because of an almost complete lack of ALAD activity, patients excrete a large amount of ALA, but not PBG, into urine. The symptoms in this disease are similar to those seen in AIP, but ...
Leal W S - - 1998
Sex pheromones have been characterized only for species in the subfamilies Rutelinae and Melolonthinae; aggregation pheromones have been identified for two species in the Dynastinae. Melolonthines utilize mainly amino acid derivatives and terpenoid compounds, but sex pheromones of rutelines are fatty acid derivatives. Various other species utilize japonilure-type lactones that ...
Schönfeld P - - 1997
The mechanism by which non-esterified long-chain fatty acids (FFA) promote mitochondrial permeability transition (MPT) is not clear. We examined with energized rat liver mitochondria the role of two possible actions of FFA in MPT, (i) the reduction of the transmembrane potential (delta psi) and (ii) the increase of the negative ...
Pawelczyk T - - 1997
Bovine brain sphingomyelin was separated into different molecular species using a reverse phase column. PLC delta 1 was inhibited by all molecular species of sphingomyelin. The extent of this inhibition was dependent on the hydrophobicity. Based on fatty acid analysis, we conclude that the inhibition of PLC delta 1 depends ...
Merényi G - - 1997
The equilibrium constant, K3, of aqueous homolysis of peroxynitrous acid into hydroxyl and nitrogen dioxide free radicals was estimated to be 5 x 10(-10) M. This value was derived from a thermodynamic cycle by use of the experimentally known delta fH degree(ONOO-,aq) = -10.8 kcal/mol and the enthalpy of ionic ...
Ross E V - - 1997
To examine the potential of using photodynamic therapy (PDT) in condylomata, we studied the distribution and kinetics of protoporphyrin IX (PpIX) formation in condylomata acuminata and adjacent normal skin after topical application of 5-aminolaevulinic acid (ALA). PpIX fluorescence spectra were measured hourly in vivo after ALA application. After gross fluorescence ...
Misra M - - 1997
Liposomes are the potent carriers of therapeutic drugs for their targeted delivery to the intracellular sites specially when the drug is hydrophilic in nature and is unable to cross the cell membrane. Lead, a major source of environmental pollution, is accumulated in the body system of both animals and humans ...
Leonardi M G - - 1997
We have examined the type of inhibition exerted by an activated preparation of the Bacillus thuringiensis delta-endotoxin CrylAa on K+-dependent leucine transport into midgut brush border membrane vesicles or epithelial cells of the isolated midgut from Bombyx mori to study its possible interaction with the amino acid symporter. K+ permeability ...
van der Meulen F W - - 1997
Bacterial resistance against antibiotic treatment is becoming an increasing problem in medicine. Therefore methods to destroy microorganisms by other means are being investigated, one of which is photodynamic therapy (PDT). It has already been shown that a variety of Gram-positive and Gram-negative bacteria can be killed in vitro by PDT ...
Kallow W - - 1997
The tripeptide delta-L-alpha-aminoadipyl-L-cysteinyl-D-valine (LLD-ACV) is synthesised by the multifunctional enzyme ACV synthetase integrating four steps of the penicillin and cephalosporin biosynthetic pathway. Peptide synthesis follows the thiotemplate mechanism from intermediates bound as thioesters to the enzyme. The formation of delta-(L-alpha-aminoadipyl)-L-cysteinyl-thioester in the absence of L-valine was shown by isolation of ...
Kirsch C - - 1997
Treatment of cultured parsley (Petroselinum crispum L.) cells with a structurally defined peptide elicitor (Pep25) of fungal origin has previously been shown to cause rapid and large changes in the levels of various desaturated fatty acids. We isolated two distinct parsley cDNAs sharing high sequence similarity with microsomal omega-6 fatty ...
Keelan M - - 1997
Previous studies have shown that isocaloric modifications in the type of lipids in the diet alter the nutrient uptake and lipid composition of the intestinal brush border membrane. In this study adult rats were fed for 2 weeks isocaloric semisynthetic diets with triglycerides enriched with either saturated (S) or polyunsaturated ...
Polcic P - - 1997
Fatty acids stimulate the oxidation rate of mitochondria isolated from the wild-type Saccharomyces cerevisiae, but do not affect significantly the respiration of mitochondria isolated from mutants, in which the ADP/ATP carrier (AAC) was either modified (R96H) or deleted (delta aac2). Similarly as in mammalian mitochondria, the transmembrane electrical potential difference ...
Sithisarankul P - - 1997
The first intermediate substrate in the heme synthetic pathway, 5-aminolevulinic acid (ALA), is neurotoxic in animal models and may be responsible for some of the adverse neurologic outcomes in lead poisoning and porphyria in adult humans. ALA is a substrate for the enzyme aminolevulinic acid dehydratase (ALAD; EC 4.2.1.24), which ...
Chardigny J M - - 1997
Several years ago, it was established that the delta 15 trans isomer of alpha-linolenic acid is converted in vivo into fatty acids containing 20 and 22 carbons (geometrical isomers of eicosapentaenoic and docosahexaenoic acids). The present study focused on the in vitro delta 6 desaturation, the first step of the ...
Fritsch C - - 1997
In photodynamic therapy with topically applied delta-aminolevulinic acid porphyrins are acting as photosensitizers. The profile of porphyrin metabolites in normal or in neoplastic skin after administration of delta-aminolevulinic acid has not been determined in detail yet. Thus, to study porphyrin biosynthesis in human skin an organ culture model was developed. ...
Jurenka R A - - 1997
Sex pheromones are used by insects as a form of chemical communication for the purpose of attracting conspecific mates. Female moths Cadra cautella and Spodoptera exigua use the diene (Z,E)-9,12-tetradecadienyl acetate as the major pheromone component. Biosynthesis of this pheromone component was demonstrated to occur through delta 11 desaturation of ...
Meesters P A - - 1997
To allow genetic modification of the fatty acid biosynthesis routes in the lipid-accumulating yeast Cryptococcus curvatus the delta 9 fatty acid desaturase gene was cloned and characterized. The 1668-bp gene encodes a protein of 556 amino acids with a calculated molecular mass of 62 kDa. The gene shows strong homology ...
Kawashima H - - 1997
Enhanced production of 5,8,11-eicosatrienoic acid (Mead acid, 20:3(omega)9) was attained by a mutant fungus, Mortierella alpina M209-7, derived from (Delta)12 desaturase-defective M. alpina Mut48. The 20:3(omega)9 production by M209-7 was 1.3 times greater than that by its parent strain, Mut48. This is thought to be due to its enhanced (Delta)6 ...
Sayanova O - - 1997
gamma-Linolenic acid (GLA; C18:3 delta(6,9,12)) is a component of the seed oils of evening primrose (Oenothera spp.), borage (Borago officinalis L.), and some other plants. It is widely used as a dietary supplement and for treatment of various medical conditions. GLA is synthesized by a delta6-fatty acid desaturase using linoleic ...
Sébédio J L - - 1997
Metabolism of conjugated isomers of linoleic acid (CLA) in rats was studied by feeding high quantities of CLA (180 mg/day) for six days to animals that had been reared on a fat-free diet for two weeks. After this period, animals were sacrificed and liver lipids extracted. High-performance liquid chromatography (HPLC) ...
Schwartz B S - - 1997
Hemoglobin in erythrocytes may be an important intravascular site of lead binding. We examined associations of hemoglobin subtypes A1 and A2 with delta-aminolevulinic acid dehydratase (ALAD) genotype, a protein that is another important site of erythrocyte lead binding. After oral administration of dimercaptosuccinic acid (DMSA-chelatable lead), we also examined 4-h ...
Madsen L - - 1997
In the liver of rats, monocarboxylic 3-thia fatty acids, tridecylthioacetic acid (C13-S-acetic acid) and tetradecylthioacetic acid (C14-S-acetic acid), increase the mRNA levels of delta 9-desaturase both in a time- and dose-dependent manner. The increased delta 9-desaturase mRNA levels were accompanied by increased delta 9-desaturase activity and increased amounts of oleic ...
Buzzi M - - 1997
The role of 24:5n-3 and 24:6n-3 as intermediate in the formation of 22:6n-3 in trout liver was examined. Microsomes prepared from trout liver converted [1-14C]-eicosapentaenoic acid (20:5n-3) to 24: 5n-3 and 24:6n-3 but not docosahexaenoic acid (22:6n-3). The radiolabeled 24:5n-3 and 24:6n-3 were isolated from the microsomal incubations by argentation ...
Davis R K - - 1997
This study compares the systemic and topical application of photofrin II and aminolevulinic acid as an intraoperative adjuvant therapy in the C3H mouse radiation-induced fibrosarcoma model. Dose-development and time-dependent studies were first conducted followed by intraoperative phototherapy studies with photofrin II and aminolevulinic acid. Study results clearly show that intraoperative ...
Adger B - - 1997
2-(2-Acetoxyethyl)cyclohexanone (4) was converted into the lactone (-)-(5) regio- and enantioselectively using 2-oxo-delta 3-4,5,5-trimethylcyclopentenyl acetyl-CoA monooxygenase, an NADPH-dependent Baeyer-Villiger monooxygenase from camphor grown Pseudomonas putida NCIMB 10007. The lactone (-)-(5) was converted into (R)-(+)-lipoic acid in six steps. In contrast cyclopentanone monooxygenase, an NADPH-dependent Baeyer-Villiger monooxygenase from cyclopentanol-grown Pseudomonas sp. ...
Cohen Z - - 1997
Polyunsaturated fatty acids (PUFAs) exogenously supplied to the red microalga Porphyridium cruentum were incorporated into cellular lipids. All the C18 PUFAs studied were desaturated by a delta 6-desaturase and all the C20 PUFAs by a delta 5-desaturase. The latter enzyme desaturated even 20:2(11, 14) to 20:3(5, 11, 14) and 20:3(11, ...
Zhang H - - 1997
Deuterium NMR spectra for the phenyl ring deuterons have been obtained for D-phenylalanine, L-phenylalanine, phenylacetic acid, and phenyl propionic acid in randomly oriented crystals of carboxypeptidase A as a function of water content. The spectra are analyzed using a two-site jump model for phenyl ring pi-flips when the ligand is ...
Willenbring S - - 1997
Previously we demonstrated the use of chemical (topical acetic acid), thermal (radiant heat) and mechanical (von Frey filament) stimuli as quantifiable behavioral response assays in the northern grass frog, Rana pipiens. Furthermore, response thresholds in all of these sensory modalities are significantly elevated by systemic morphine injections, which can be ...
Kudo N - - 1996
The effects of cadmium (Cd) on the fatty acid composition and delta 9 desaturation activity were studied in hepatocytes which had been cultured in serum-free medium. The aim of this study was to determine whether the inhibition of delta 9 desaturase seen in Cd-treated rat liver (Kudo et al. (1991) ...
Coque J J - - 1996
Formation of the tripeptide delta-(L-alpha-aminoadipyl)-L-cysteinyl-D-valine (Aad-Cys-Val) is catalyzed by a multienzyme peptide synthetase encoded by the pcbAB gene in producers of beta-lactam antibiotics. The pcbAB gene of Nocardia lactamdurans was overexpressed in Streptomyces lividans giving a high Aad-Cys-Val synthetase activity. The synthetase was purified 2785-fold to near homogeneity showing a ...
Rohl C A - - 1996
The helix propagation and N-cap propensities of the amino acids have been measured in alanine-based peptides in 40 volume percent trifluoroethanol (40% TFE) to determine if this helix-stabilizing solvent uniformly affects all amino acids. The propensities in 40% TFE are compared with revised values of the helix parameters of alanine-based ...
< 4 5 6 7 8 9 10 11 12 13 14 >