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Results 601 - 650 of 1169
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Nguyen M V - - 1998
Five new dihydroxamic acid ligands (L) (8, 10a, 10b, 10c and 13) have been synthesised and characterised as potential chelating agents for iron (Fe3+). The log stability constants of Fe2L3 and FeL+ from Fe3+ and L2- have been estimated to be log beta = 61.96 and log beta 1 = ...
Giulivi C - - 1998
The oxidation of myoglobin by H2O2 yields ferrylmyoglobin, which contains two oxidizing equivalents: the oxoferryl complex and an amino acid radical. This study examines the electron paramagnetic resonance (EPR) properties of the resulting amino acid radicals and their inherent kinetic features at [H2O2]/[protein] ratios close to physiological conditions (i.e., < ...
Singh A - - 1998
The present study evaluates the potential of smokeless tobacco to translactationally modify the chemopreventive efficacy of phytic acid and butylated hydroxyanisole (BHA) via modulation of the hepatic xenobiotic detoxication system and antioxidant defense mechanism in the murine system. Phytic acid (1000 mg/kg b.w./day) by gavage while BHA (1% w/w) in ...
Miyajima H - - 1998
Aceruloplasminemia is a newly recognized autosomal recessive disorder of iron metabolism that causes neurodegeneration of the retina and basal ganglia as well as diabetes mellitus. Our previous studies suggested that increased susceptibility to plasma lipid peroxidation secondary to iron accumulation may contribute to the pathogenesis in this disease. We now ...
Dunning J C - - 1998
Reduced, transition metal cations commonly enhance oxidative damage to cells caused by hydroperoxides formed as a result of oxygen metabolism or added externally. As expected, the cations Fe2+ and Cu+ enhanced killing of Streptococcus mutans GS-5 by hydroperoxides. However, unexpectedly, they also induced lethal damage under fully anaerobic conditions in ...
Kono Y - - 1998
Chlorogenic acid, a dietary antioxidant, effectively inhibited the iron-induced lipid peroxidation of bovine liver microsomes in a concentration-dependent manner. In the Fenton-type reaction, chlorogenic acid inhibited the production of the hydroxyl radical by iron-EDTA or iron-ADP, while iron plus chlorogenic acid did not generate the hydroxyl radical. The formation of ...
Rose P D - - 1998
Acid mine drainage pollution may be associated with large water volume flows and exceptionally long periods of time over which the drainage may require treatment. While the use and role of sulphate reducing bacteria has been demonstrated in active treatment systems for acid mine drainage remediation, reactor size requirement and ...
Yamanishi H - - 1997
We established a method for fully automated measurement of total iron-binding capacity (TIBC) in serum without separation of the unbound excess iron after saturating serum transferrin. After saturation of serum transferrin with an excess amount of iron (first step), the unbound iron was eliminated by formation of a complex with ...
Smith P A - - 1997
Various uses of rosin and exposure to its resin acid constituents have been associated with dermal and pulmonary sensitization. Methodology is presented to detect resin acids common to rosin (such as abietic and dehydroabietic acid) found in aerosol from heated rosin flux. Air filtration, solvent filter extraction, and gas chromatography/mass ...
Rivkin G - - 1997
A major consideration in the selection of new and improved iron chelators for clinical use is preferential interaction with the most toxic iron compartment. We describe the biologic properties of a new synthetic hexadentate iron chelator (IRC011) that is a substituted polyaza compound. Unlike deferoxamine (DF ), the polyaza structure ...
Briganti F - - 1997
A catechol 1,2-dioxygenase (C1,2O) has been purified to homogeneity from Acinetobacter radioresistens grown on phenol as the sole carbon and energy source. The C1,2O appears to be a homodimer, with a molecular mass of 78,000 Da. At relatively high ionic strengths (0.5 M Na2SO4) subunit dissociation occurs and the monomeric ...
Challa A - - 1997
Several epidemiological studies point to a strong correlation between nutrient composition of the diet and cancer of the colon. Phytic acid, present in grains, has been credited with reducing the risk of cancer of the colon. A number of reports are available indicating the benefits of green tea consumption in ...
Ollinger K - - 1997
Primary cultures of rat hepatocytes were subjected to amino acid and serum deprivation for 4 h. This treatment augmented the sensitivity to ensuing hydrogen peroxide exposure for 30 min. The by nutrient deprivation-increased autophagocytosis was confirmed by transmission electron microscopy and uptake of the lysosomotropic weak base acridine orange within ...
Martin B L - - 1997
Calcineurin was activated at 30 degrees C by incubation with dipicolinic acid, a metal chelator, in the absence of activating, exogenous Mn2+. The activation reached a plateau after 90 min with 8- to 12-fold higher activity. Inclusion of the activating metal Mn2+ (1.0 mM) in the incubation mixture slightly lessened ...
Satoh K - - 1997
Five heavy metal antagonists were compared for their specificity of chelating action against copper (CuCl, CuCl2) and iron (FeCl2, FeCl3). ESR spectroscopy showed that both copper and iron significantly enhanced the radical intensity of ascorbate and sodium 5,6-benzylidene-L-ascorbate (SBA). Equimolar concentrations of dimercaprol efficiently chelated all these metals, thus significantly ...
Fan T W - - 1997
Root exudates in the rhizosphere are vital to the normal life cycle of plants. A key factor is phytometallophores, which function in the nutritional acquisition of iron and zinc and are likely to be important in the uptake of pollutant metals by plants. Unraveling the biochemistry of these compounds is ...
Vincenzetti S - - 1997
Cytidine deaminase, a tetrameric enzyme purified from human placenta, was shown to contain a single atom of tightly bound zinc per subunit by Inductively Coupled Plasma Optical Emission Spectrometry analysis. The metal appears to be involved in catalysis, as suggested by the inhibition exerted by 1,10-phenanthroline and dipicolinic acid. This ...
Collis C S - - 1997
The relationship between intake of iron with ascorbic acid and their uptake into the plasma and liver of guinea pigs was studied. The influence on the antioxidant/pro-oxidant balance of liver microsomes was also determined. Animals were fed a standard pelleted diet low in iron and ascorbic acid for 35 days. ...
Olivares M - - 1997
The chemical properties of ferrous bis-glycine chelate allow for its use as a fortificant in fluid, high fat vehicles. This chemical form may also protect iron from the inhibitory or enhancing effects of the diet on iron absorption. Alternatively, iron bis-glycine chelate may be absorbed by a mechanism independent of ...
Kazimierczak A - - 1997
The two first transition metal carbonyl isothiocyanates were prepared in high yield within two steps from photolysis of CpFe(CO)2I and 3- or 4-aminophthalimide in the presence of diisopropylamine followed by reaction with thiophosgene/triethylamine. Their reaction with a model amino acid, i.e. beta-alanine, was performed and led to the expected thioureas. ...
Almaas R - - 1997
Infant cereals and formulas are usually fortified with iron to prevent iron deficiency. To enhance iron bioavailability, supplemental ascorbic acid is recommended. Ascorbic acid is considered to be an antioxidant in vivo, but has pro-oxidant effects when exposed to non-protein-bound iron. We measured formation of free radicals in cereals and ...
Rule D C - - 1997
The purpose of this study was to demonstrate direct transesterification of fatty acids of tissue total lipids with boron-trifluoride in methanol. Adipose tissue, muscle, and liver samples obtained from market-weight lambs, were transesterified with 14% boron-trifluoride in methanol at 80 °C. Total lipids of additional samples were first solvent-extracted and ...
Satoh K - - 1997
Four antioxidants, sodium ascorbate, gallic acid, n-propyl gallate and caffeic acid, induced apoptotic cell death in human promyelocytic leukemic HL-60 cells. The effects of all these compounds were enhanced by CuCl2 or deferoxamine mesylate, an iron chelator, but were reduced by FeCl3. ESR spectroscopy showed that both CuCl2 and FeCl3 ...
Guard-Petter J - - 1997
Salmonella enterica grown on solid medium containing iron, thiosulfate and 100 mM hexoses and amino acids underwent cell surface differentiation involving increased flagellation (electrophoretic isotypes 60, 54 and 50 kDa), conversion from rough to smooth lipopolysaccharide, and assembly of a matrix that penetrated 1.4% agar. Flagellation was also induced in ...
Sevrioukova I - - 1997
Cytochrome P450BM-3, a catalytically self-sufficient fatty acid monooxygenase from Bacillus megaterium, is a multidomain protein containing heme, FAD, and FMN. Previous attempts to reconstitute the fatty acid monooxygenase activity of intact P450BM-3 utilizing equimolar concentrations of the separate heme (BMP) and reductase (BMR) domains, have been unsuccessful because two-electron reduced ...
Khalil-Rizvi S - - 1997
When Pseudomonas putida ATCC 39167 and plant-deleterious Pseudomonas fluorescens A225 were grown in an iron-deficient culture medium, they each produced two different novel yellow-green fluorescent pseudobactins: P39167-I, II and PA225-I, II. Pseudobactin P39167-I has a molecular formula of C46H65O23N13 and is monoanionic at neutral pH. P39167-II has the molecular formula ...
Glahn R P - - 1997
Human and animal studies have shown that amino acids and peptides influence iron absorption from the intestinal lumen. This study was conducted using Caco-2 cell monolayers as the experimental model to determine whether similar effects on iron absorption occur. Conditions were chosen to mimic the pH of the intestinal lumen ...
Davidsson L - - 1997
Iron bioavailability from an infant cereal made of wheat flour with a low extraction rate (70%) and cow milk was measured in infants by using a stable-isotope technique. A dephytinized infant cereal was prepared by adding commercial phytase during manufacture, resulting in degradation of 88% of the native phytic acid. ...
Landman O - - 1997
Isopenicillin N synthase (IPNS) is a non-heme ferrous iron dependent dioxygenase that catalyses the ring closure of delta-(L-alpha-aminoadipoyl)-L-cysteinyl-D-valine (ACV) to isopenicillin N. We previously used site-directed mutagenesis to identify in the IPNS of Streptomyces jumonjinensis two histidines and one aspartic acid that are essential for activity. The recent crystal structure ...
Kishimoto K - - 1997
The physiological features of the mildiomycin production by Streptoverticillium rimofaciens were examined in iron-sufficient and -deficient media. Activities of NADP-linked glutamate dehydrogenase (GDH) and aspartate aminotransferase (AAT) were markedly enhanced by the addition of 10 micrograms/ml of ferrous ion into culture. Ammonium nitrogen assimilation increased with the increase in mildiomycin ...
De Loecker P - - 1997
In an attempt to quantitatively evaluate the destructive effects of free radicals on metabolism, freshly prepared and cryopreserved isolated rat hepatocytes were exposed to and incubated with Fe2+ compounds, reputedly inducing oxygen-derived free radicals (OFR) capable of attacking the lipid structures of cellular membranes. Malondialdehyde (MDA) formation was interpreted as ...
Tichelaar H Y - - 1997
Severe iron deficiency was introduced in rats by feeding outbred male Wistar rats a purified diet that was either adequate or deficient in iron. The rats were weighed regularly over 4 weeks to monitor body weight differences, after which blood was drawn from a subsample to determine the haemoglobin concentrations ...
Hassett D J - - 1997
We report the discovery of fumC, encoding a fumarase, upstream of the sodA gene, encoding manganese superoxide dismutase, in Pseudomonas aeruginosa. The fumC open reading frame, which terminates 485 bp upstream of sodA, contains 1,374 bp that encode 458 amino acids. A second 444-bp open reading frame located between fumC ...
Maier R H - - 1997
Cisplatin (CDDP)-sensitive and -resistant human ovarian cells were studied in vitro with the objective of enhancing CDDP cytotoxicity by the addition of a metal and the chelate ethylenediaminetetraacetic acid (EDTA), to the CDDP. Chelateable elements, such as bismuth, calcium, cadmium, copper, iron, magnesium, selenium, vanadium, and zinc, when added to ...
Sedlák E - - 1997
Effects of two polyanions (heparin, Nafion) on absorption and CD spectra in the Soret region, and on fluorescence of ferricytochrome c were investigated. The conformational state of ferricyt c in the complexes with studied polyanions is significantly different. Whereas heparin affects the structure in the heme region of ferricyt c ...
Phillippy B Q - - 1997
Iron chelates of inositol 1,2,3-trisphosphate and inositol 1,2,3,6-tetrakisphosphate lacked free coordination sites and prevented the iron-catalyzed oxidation of ascorbic acid and peroxidation of arachidonic acid. In contrast, iron chelates of inositol 1,2,6-trisphosphate and inositol 1,2,5,6-tetrakisphosphate contained available coordination sites, permitted iron-catalyzed ascorbic acid oxidation, and enhanced arachidonic acid peroxidation. It ...
Pallauf J - - 1997
In the nutrition of monogastric animals phytate-P represents a poorly available source of phosphorus, especially in the case of diets low in phytase activity. Similarly the bioavailability of different minerals and trace elements is considerably reduced by phytate complexes. High concentrations of Ca increase the anti-nutritive effect of phytic acid ...
Modgil R - - 1997
Effect of bruchid infestation on selected antinutritional factors, saponin, phytic acid and trypsin inhibitor activities, of three (mung bean, chickpea and pigeon pea) legumes stored for six months was studied. The three antinutritional factors, saponin, phytic acid and trypsin inhibitor activity (TIA), increased with increased storage period. Saponin, phytic acid ...
Rosenthal P J - - 1996
Erythrocytic malaria parasites transport large quantities of erythrocyte cytoplasm to an acidic food vacuole, where hemoglobin is degraded. Globin is hydrolysed to free amino acids, which are subsequently incorporated into parasite proteins. Potentially toxic heme moieties are polymerized to hemozoin and also probably provide necessary parasite iron. Our understanding of ...
Liyanage C - - 1996
OBJECTIVE: To study absorption of iron from Centella gruel and the enhancing effect of ascorbic acid in young adult males. DESIGN: An in vivo absorption study. SETTING: Faculty of Medicine, Galle. METHODS: The percentage of iron absorbed from the Centella gruel was measured using a double isotope technique with 55Fe ...
Jones M M - - 1996
The relative effectiveness of 20 iron chelating agents in suppressing the growth and multiplication of Trypanosoma cruzi epimastigotes has been examined in vitro. 1,2-Dimethyl-3-hydroxypyrid-4-one (L1) and several of its newly synthesised N-substituted analogs containing hydrophobic substituents were significantly more effective than deferoxamine, even though they possess only two donor sites ...
Bartov I - - 1996
A study was carried out to evaluate the effect of storage duration of corn on its chemical composition (DM, protein, fat, amino acid, and fatty acids) and nutritional value for chicks, with an emphasis on AMEn. Freshly harvested whole grains were stored for 110 mo in covered galvanized iron cans, ...
Hall H K - - 1996
The response of Salmonella typhimurium to low pH includes a low-pH protection system called the acid tolerance response (ATR). The iron-regulatory protein Fur has been implicated in the ATR since fur mutants are acid sensitive and cause altered expression of several acid shock proteins (J. W. Foster, J. Bacteriol. 173:6896-6902, ...
Ali M S - - 1996
Immunoconjugates sometimes suffer changes in immunoreactivity and tumor targeting because the chelators used interfere with antigen binding. To try to circumvent such problems, two new homobifunctional chelating agents, 2,6-bis[p-[(beta-maleimidopropionyl) amino]benzyl]diethylenetriamine- N,N,N',N",N"-pentaacetic acid (MPBz-DTPA) and 2,9-bis [p-(beta-maleimidopropionyl)amino]benzyl] triethylenetetraamine-N,N,N',N',N",N"-hexaacetic acid (MPBz-TTHA), were synthesized for chelation of 111In and 90Y metal ions. Each ...
Gaymard F - - 1996
A ferritin cDNA, AtFer1, from seedlings of Arabidopsis thaliana has been characterized. The deduced amino acid sequence of the AtFer1 protein indicates that A. thaliana ferritin shares the same characteristics as the plant ferritin already characterized from the Leguminosae and Graminacea families: (i) it contains an additional sequence in its ...
Lindqvist Y - - 1996
The three-dimensional structure of recombinant homodimeric delta9 stearoyl-acyl carrier protein desaturase, the archetype of the soluble plant fatty acid desaturases that convert saturated to unsaturated fatty acids, has been determined by protein crystallographic methods to a resolution of 2.4 angstroms. The structure was solved by a combination of single isomorphous ...
Ratledge C - - 1996
Carboxymycobactin, in which the usual intracellular mycobactin siderophore is modified by possession of a carboxylic acid group, has been isolated as a second extracellular siderophore from culture filtrates of Mycobacterium smegmatis grown under iron-deficient conditions. (The primary siderophore is an exochelin which is a trihydroxamate, pentapeptide derivative). There may be ...
Owen R W - - 1996
The hypoxanthine/xanthine oxidase enzyme system is known to produce the superoxide ion and hydrogen peroxide during the hydroxylation of hypoxanthine via xanthine to uric acid. When chelated iron is included in this system, superoxide reduces iron (III) to iron(II) and the iron(II)-chelate further reacts with hydrogen peroxide to form the ...
Munro A W - - 1996
Rapid events in the processes of electron transfer and substrate binding to cytochrome P-450 BM3 from Bacillus megaterium and its constituent haem-containing and flavin-containing domains have been investigated using stopped-flow spectrophotometry. The formation of a blue semiquinone flavin form occurs during the NADPH-dependent reduction of the flavin domain and a ...
Bechara E J - - 1996
Highly reactive oxyradicals can be generated in vitro by iron-catalyzed aerobic oxidation of synthetic and naturally occurring substances capable of enolization in aqueous medium. Of biological interest are alpha-hydroxy- and alpha-aminocarbonyls such as carbohydrates, 5-aminolevulinic acid, and aminoacetone which tautomerize to the corresponding enediols and enolamines and yield oxyradicals initiated ...
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