Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “ERGOTHIONEINE”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 163 records · Page 9Linked to original sources
PubMed1985

Characteristics of Mycoplasma strains isolated from stallion semen.

Eleven mycoplasma strains were isolated from the semen of 24 stallions. Eight of these strains were identified as Mycoplasma equigenitalium. Three strains which hydrolized arginine could not be identified. The growth inhibition test with immune sera against M. arginini and M. equirhinis was negative. Antibiotic sensitivity test showed that all strains were sensitive to four antibiotic of tetracycline group (oxytetracyclin, minocycline, transcycline and vibramycin). Lincomycin and gentamycin appeared to be the most active against all the strains. Comparative analysis of routine semen examination did not reveal any difference between ejaculates infected with mycoplasma and free of these organisms. However, the levels of certain biochemical components of the semen plasma (glycerylphosphorylcholine, ergothioneine, fructose and of the semen plasma (glycerylphosphorylcholine, ergothioneine, fructose and total protein) from mycoplasma-positive ejaculates were significantly lower than in the semen plasma from mycoplasma free ejaculates.

Animals↗
PubMed2005

Evaluation of photolyase (Photosome) repair activity in human keratinocytes after a single dose of ultraviolet B irradiation using the comet assay.

Photosome is constituted of photolyases included in liposomes. Photolyase is a bacterial enzyme that can repair ultraviolet B (UVB)-induced cyclobutane pyrimidine dimers (CPD) in eukaryotic cells. A modified version of the alkaline comet assay has been set up to evaluate the repair activity of this enzyme after a single dose of UVB (312 nm, 0.06 J/cm2) in human keratinocytes. The formation of single strand breaks (SSB) induced by the UVA photoactivation of the enzyme (1.2 J/cm2) was inhibited by the pretreatment of the cells with 4 mM L-ergothioneine (ERT) during 30 min at 37 degrees C. To increase the sensitivity of the comet assay, an additional lysis was used with a buffer containing sodium dodecyl sulfate (0.5%) and proteinase K (0.1 mg/ml) for 60 min at 37 degrees C. Unrepaired CPD by photolyase were revealed by a second enzymatic treatment with T4 endonuclease V, a CPD specific glycosylase. UVB irradiation increased the SSB level in keratinocytes and additional T4NV treatment enhanced this SSB level by 1.5-2.0-fold confirming that CPD were the major base modifications generated by UVB irradiation. UVA-photoactivated Photosome repaired CPD lesions and decreased the SSB levels by 2.6-3.3-fold. Photosome could be an additional component of sunscreens to reduce the development of skin cancer.

Cells, Cultured↗
PubMedDate not supplied

Intracellular antioxidants: from chemical to biochemical mechanisms.

Intracellular antioxidants include low molecular weight scavengers of oxidizing species, and enzymes which degrade superoxide and hydroperoxides. Such antioxidants systems prevent the uncontrolled formation of free radicals and activated oxygen species, or inhibit their reactions with biological structures. Hydrophilic scavengers are found in cytosolic, mitochondrial and nuclear compartments. Ascorbate and glutathione scavenge oxidizing free radicals in water by means of one-electron or hydrogen atom transfer. Similarly, ergothioneine scavenges hydroxyl radicals at very high rates, but it acts more specifically as a chemical scavenger of hypervalent ferryl complexes, halogenated oxidants and peroxynitrite-derived nitrating species, and as a physical quencher of singlet oxygen. Hydrophobic scavengers are found in cell membranes where they inhibit or interrupt chain reactions of lipid peroxidation. In animal cells, they include alpha-tocopherol (vitamin E) which is a primary scavenger of lipid peroxyl radicals, and carotenoids which are secondary scavengers of free radicals as well as physical quenchers of singlet oxygen. The main antioxidant enzymes include dismutases such as superoxide dismutases (SOD) and catalases, which do not consume cofactors, and peroxidases such as selenium-dependent glutathione peroxidases (GPx) in animals or ascorbate peroxidases (APx) in plants. The reducing coenzymes of peroxidases, and as a rule all reducing components of the antioxidant network, are regenerated at the expense of NAD(P)H produced in specific metabolic pathways. Synergistic and co-operative interactions of antioxidants rely on the sequential degradation of peroxides and free radicals as well as on mutual protections of enzymes. This antioxidant network can induce metabolic deviations and plays an important role in the regulation of protein expression and/or activity at the transcriptional or post-translational levels. Its biological significance is discussed in terms of environmental adaptations and functional regulations of aerobic cells.

Animals↗
PubMed2001

Novel thiols of prokaryotes.

Glutathione metabolism is associated with oxygenic cyanobacteria and the oxygen-utilizing purple bacteria, but is absent in many other prokaryotes. This review focuses on novel thiols found in those bacteria lacking glutathione. Included are glutathione amide and its perthiol, produced by phototrophic purple sulfur bacteria and apparently involved in their sulfide metabolism. Among archaebacteria, coenzyme M (2-mercaptoethanesulfonic acid) and coenzyme B (7-mercaptoheptanoylthreonine phosphate) play central roles in the anaerobic production of CH4 and associated energy conversion by methanogens, whereas the major thiol in the aerobic phototrophic halobacteria is gamma-glutamylcysteine. The highly aerobic actinomycetes produce mycothiol, a conjugate of N-acetylcysteine with a pseudodisaccharide of glucosamine and myo-inositol, AcCys-GlcNalpha(1 --> 1)Ins, which appears to play an antioxidant role similar to glutathione. Ergothioneine, also produced by actinomycetes, remains a mystery despite many years of study. Available data on the biosynthesis and metabolism of these and other novel thiols is summarized and key areas for additional study are identified.

Cysteine↗
PubMed1975

Biochemistry of stallion semen.

Stallion semen has several chemical characteristics not commonly encountered in other animals. It contains very little fructose and the spermatozoa possess only limited fructolytic ability under anaerobic conditions. By determining some of the characteristic constituents such as ergothioneine, citric acid, glycerylphosphorylcholine and certain glycosidases, it is possible to obtain a quantitative measure of the secretory contribution of the ampulla, seminal vesicle and epididymis, respectively, towards the final composition of the whole ejaculate. By analysing separately the various fractions of a split ejaculate, including the so-called tail-end sample, it is possible to detect and pinpoint abnormalities in the functional state of the various male accessory organs and in the entire process of ejaculation.

Animals↗
PubMed1979

The effect of vesiculectomy on seminal characteristics in the stallion.

Successful unilateral extirpation of an inflamed seminal vesicle in a stallion led to systematic trials of the influence of a reduction and absence of the secretion of this gland upon semen characteristics. Operations were performed by the method described for the bull. The volume of ejaculates dropped and sperm concentration per ml increased in each of 2 stallions from which the seminal vesicles had been uni- or bi-laterally removed. Total sperm number and motility remained uninfluenced, but the percentage of eosin-stained spermatozoa increased in the unilaterally operated stallion and the percentage of abnormal spermatozoa increased significantly in both. Concentration of citric acid per ml and per ejaculate was significantly reduced after bilateral vesiculectomy. Ergothioneine concentration per ml increased in the unilaterally and in the bilaterally operated stallion.

Animals↗
PubMed1988

Cellular response to oxidative stress at sulfhydryl group receptor sites on the erythrocyte membrane.

Ellman's reagent was used to induce an oxidative stimulus on the exofacial membrane sulfhydryl groups of the human erythrocyte. Thiol-disulfide exchange occurring extracellularly was monitored using resonance Raman spectroscopy, and intracellular changes were observed by 1H spin echo nuclear magnetic resonance spectroscopy of the intact cell. The stimulus caused oxidation and depletion of the glutathione pool, which was followed at higher concentrations of Ellman's reagent by a depletion of intracellular ergothioneine levels. Larger changes are induced intracellularly than would be expected from the stoichiometry of the reaction at the exofacial surface. A mechanism is proposed which links exofacial sulfhydryl receptor sites via the transport proteins to spectrin and glutathione. The consequences for the cellular redox balance of an extracellular stimulus of this type are discussed.

Blood Glucose↗
PubMed1975

[Relationship of citric acid concentration to various quality indices of the equine ejaculate].

The paper describes the relation of citric acid to other chemical and biological indices of the fertility of stallion sperm. A positive relation was found between citric acid and the density and motility of spermatozoa, to the concentration of ergothioneine, and hemolytic activity, and a negative relation to pH and to the polarographic activity of proteins. Attention is drawn to the important nutritional function of citric acid.

Animals↗
PubMed1993

Direct interception of mutagens and carcinogens by biomolecules.

Five points are emphasized: 1. Chemical interception and mere physical exclusion of mutagens and carcinogens constitute the major means by which mutations in cellular DNA are prevented. DNA repair processes comprise critical, but relatively minor, modes of genetic protection. 2. Disruption of a mutagen-interception defense mechanism can lead to substantial increases in mutagenesis and can preordain sites to eventual tumor formation. 3. Quantitation of the relative contributions of various blocking molecules is often simplified by the fact that protection can be calculated merely through knowledge of the measured concentration of the antimutagen and its rate of reaction with specific mutagens as measured in straightforward in vitro tests. 4. Two recently recognized defensive molecules, carnosine and ergothioneine, are put ++forward as examples of interesting chemical interceptor molecules. 5. Essentially all antimutagens are in fact "double-edged swords." Situations can be artificially constructed that can lead to generation of toxic species from molecules that are normally antimutagens; in isolated cases some of these interactions can be pictured as having deleterious consequences in vivo. This may be one reason why a number of important antimutagens are often sequestered, either in different tissues or by binding to dispensable macromolecules.

Animals↗
PubMed1985

Direct observation of the NAD glycohydrolase reaction in human erythrocytes using NMR spectroscopy.

The hydrolysis of NAD by the extracellular membrane-associated enzyme NAD glycohydrolase was shown to be readily followed in concentrated suspensions of human erythrocytes using 1H spin-echo nuclear magnetic resonance spectroscopy (NMR). The maximal rate of the reaction was determined and the inhibitory effect of nicotinamide was confirmed by direct NMR observation. In addition, arginine, ergothioneine and iodoacetate did not influence the reaction rate. 31P NMR analyses of reaction media from whole cells showed that no extraneous degradation of NAD occurred and the only phosphate-containing product was ADP-ribose.

Adenosine Diphosphate Ribose↗
PubMedDate not supplied

Stimulation of mucosal uptake of selenium from selenite by some thiols at various sites of rat intestine.

The influence of several thiols (conc. 1 mmol/L) on mucosal uptake of 75Se from 75Se-labeled selenite (conc. 10 mumol/L) across the brush border of rat jejunum and cecum was investigated in vitro using a short-term uptake technique. L-Cysteine (L-Cys) stimulated 75Se uptake in the mid- and distal jejunum and cecum, but not in the proximal jejunum. The effect was maximal in the distal jejunum. D-Cys was less effective in the jejunum and similarly effective in the cecum. L-Leucine (L-Leu) and L-glutamic acid significantly reduced the stimulatory effect of L-Cys on Se uptake in the distal jejunum, whereas the respective effect of D-Cys was not diminished by L-Leu. Cysteamine stimulated mucosal 75Se uptake at all intestinal sites tested, whereas the effect of mercaptopyruvate was restricted to the distal jejunum. Thioglycolate also enhanced 75Se uptake in the distal jejunum. The stimulatory effects of L-Cys, mercaptopyruvate, and thioglycolate were Na(+)-dependent, whereas the effect of cysteamine also occurred in the absence of Na+. Mercaptosuccinate, D-penicillamine, ergothioneine, and thiosulfate did not enhance mucosal 75Se uptake. It is concluded from these findings that the reaction of some thiols with selenite results in Se compounds that are rapidly absorbed by the intestinal epithelium through various Na(+)-dependent and Na(+)-independent mechanisms. The high bioavailability of Se from selenite found by others might thus be the result of the presence of thiols in the gastrointestinal tract.

Analysis of Variance↗
PubMed2026

Organic Molecules are Involved in Ni-Struvite Biomineralization by Streptomyces mirabilis.

The Gram-positive, filamentous soil bacterium Streptomyces mirabilis P16B-1 has been shown to tolerate high environmental concentrations of Ni. The extremely high metal tolerance is partly provided through biomineralization, observed for both Mg bearing struvite and Ni-struvite where Ni ions replace Mg in the mineral lattice. The minerals showed different morphologies. This led us to assume that excreted substances may have the capacity to influence the mineral formation process that occurs at a distance to the cells. Here, we could show with metabolomics and proteomics studies that 23 metabolites as well as 18 proteins potentially co-precipitate with the minerals. Secreted secondary metabolites reduced in the supernatant after mineralization were identified as ergothioneine, diacetyllegionaminic acid, nevaltophin F, and diaminonaphthalene. The compounds phenylacetaldehyde and margaric acid also reduced after mineral precipitation did not alter mineral macromorphology. In addition, ten proteins that co-precipitated with statistical significance were predicted to be secreted. Among those, a specific nickel binding protein, NikA, was reduced in high amounts from the supernatant upon crystal formation. The potential of secreted organic molecules and proteins to bind specific surfaces of the mineral thereby redirecting crystal growth in a microbially influenced biomineralization process. Implications for biotechnological metal-struvite use are discussed.

Nickel↗
PubMed1991

Measurement of biological thiols and disulfides by high-performance liquid chromatography and electrochemical detection of silver mercaptide formation.

A rapid and sensitive method is described for the measurement of picomole levels of the biological thiols glutathione, cysteine, penicillamine, cysteamine, and ergothioneine by a combination of high-performance liquid chromatography and electrochemical detection (ECD). The compounds were separated isocratically on a reversed-phase C18 column by ion-pair chromatography with a mobile phase containing 5 mM acetic acid and 2.5 mM sodium 1-octanesulfonate. After chromatographic separation, the eluate was combined with silver nitrate dissolved in ammonium nitrate buffer at pH 10.5. A platinum disc electrode was used at -0.1 V vs Ag/AgCl to detect the amount of silver ions that had been consumed by the reaction with thiols. For measurement of disulfide, S-sulfonation with sodium sulfite or electroreduction were used to cleave the disulfide, and the thiol anions produced were detected by HPLC-ECD as for the reduced forms. The method was used to assay thiols and disulfides in biological materials.

Adult↗
PubMed1992

Inhibition by thiols of copper(II)-induced oxidation of oxyhemoglobin.

The ability of thiols, 2-imidazolethiones and uric acid to protect bovine oxyhemoglobin from copper(II)-induced oxidation to methemoglobin was investigated. The oxidation of oxyhemoglobin by Cu(II) proceeded in two phases: (1) an initial rapid reaction (less than 30 s) followed by (2) a slower reaction that carried it to completion. Thiols, including N-acetyl-L-cysteine, DL-dithiothreitol, reduced glutathione, DL-homocysteine, 2-mercaptoethanol and 2- and 3-mercaptopropionic acid, whose sulfhydryl groups were slowly oxidized by Cu(II) (with the exception of 2-mercaptopropionic acid), protected oxyhemoglobin in both phases of the reaction. Other thiols, including L-cysteine, cysteamine, and D-penicillamine, whose sulfhydryl groups were readily oxidized by Cu(II), protected hemoglobin initially, but within 2-4 min, the rate of methemoglobin formation was the same as Cu(II)-treated oxyhemoglobin. 2-Mercaptoimidazole and 1-methyl-2-mercaptoimidazole, which complex Cu(II) and inhibit Cu(II)-catalyzed oxidation of ascorbic acid, also protected hemoglobin in the initial phase, but not in the second phase. Uric acid, L-ergothioneine, and thiourea did not protect oxyhemoglobin in either the fast or slow phase. Cu(II) may have a coordination site involved in the oxidation of hemoglobin that is not blocked by the 2-imidazolethiones, uric acid, or the oxidized thiols. It is concluded that certain thiols that complex Cu(II) and are not rapidly oxidized will protect oxyhemoglobin from Cu(II)-induced oxidation, but the thiols are no longer effective once they are oxidized.

Animals↗
PubMed1986

Thiol-induced hydroxyl radical formation and scavenger effect of thiocarbamides on hydroxyl radicals.

The effects of thiols and thiocarbamides on hydroxyl radical (.OH) formation by the hypoxanthine(HYP)-xanthine oxidase(XOD)-Fe3+ .EDTA system were investigated in the range of 0.5-5 mM by colorimetrically measuring salicylate hydroxylation. Thiocarbamides powerfully inhibited the hydroxylation while thiols showed a paradoxical effect, enhancing it at low concentrations, but inhibiting it at high ones. Thiols in the presence of Fe3+ .EDTA generated superoxide anions (O2-.) and .OH during the oxidation, but thiocarbamides did not. A study of the effect of ergothioneine, a thiocarbamide present in mammals, on the .OH spin adduct of 5,5-dimethyl-1-pyrroline-N-oxide(DMPO) by EPR spectrometry showed that it effectively decreased the .OH spin adduct without causing the appearance of other signals. Reaction mechanisms are proposed for the O2-. evolution and .OH formation by the thiols themselves in the presence of Fe3+ .EDTA and .OH with thiols and thiocarbamides.

Chemical Phenomena↗
PubMed1982

A proton nuclear magnetic resonance study of the binding of methylmercury in human erythrocytes.

The binding of methylmercury, CH3Hg(II), by small molecules in the intracellular region of human erythrocytes has been studied by 1H-NMR spectroscopy. To suppress or completely eliminate interfering resonances from the much more abundant hemoglobin protons, spectra were measured by a technique based on the transfer of saturation throughout the envelope of hemoglobin resonances following a selective presaturation pulse or by the spin-echo Fourier transform method. With these techniques, 1H-NMR spectra were measured for the more abundant intracellular small molecules, including glycine, alanine, creatine, lactic acid, ergothioneine and glutathione, both intact and hemolyzed erythrocytes to which CH3Hg(II) had been added. The results for intact erythrocytes indicate that part of the CH3Hg(II) is complexed by intracellular glutathione. These results also indicate that exchange of CH3Hg(II) among glutathione molecules is fast, with the average lifetime of a CH3Hg(II)-glutathione complex estimated to be less than 0.01 s. From exchange-averaged chemical shifts of the resonance for the proton on the alpha-carbon of the cysteine residue of glutathione, it is shown that, in hemolyzed erythrocytes, the sulfhydryl group of glutathione binds CH3Hg(II) more strongly than the sulfhydryl groups of hemoglobin.

Erythrocytes↗
PubMed1982

A proton nuclear magnetic resonance study of the interaction of mercury with intact human erythrocytes.

The binding of mercuric ion (Hg(II)) by small molecules in the intracellular region of intact human erythrocytes has been studied by 1H-NMR spectroscopy. HgCl2 added to intact erythrocytes in saline-glucose suspension is found to cross the membrane and reach an equilibrium distribution among the molecules of the erythrocyte within 4 min. In the intracellular region Hg(II) reacts with GSH and hemoglobin to form the ternary mixed-ligand complex GSH-Hg(II)-hemoglobin. The analogous complex with ergothioneine is formed after all the GSH is complexed. 1H-NMR spectra show that the GSH-Hg(II)-hemoglobin complex also forms in simpler solutions containing HgCl2, GSH and hemoglobin, whereas the complex Hg(GSH)2 predominates in solutions of GSH and HgCl2. The lifetime of the GSH in the GSH-Hg(II)-hemoglobin complex is shown to be less than 30 s, which provides direct evidence for the first time that Hg(II) complexes in biological systems are quite labile, even though their thermodynamic stability is large. The effectiveness of eight sulfhydryl-containing ligands, some of which have been used as antidotes for Hg(II) poisoning, for releasing GSH from its Hg(II) complex in hemolyzed erythrocytes was also studied. Dithiol ligands were found to be more effective than monothiols, with dithioerythritol the most effective of the dithiols.

Antidotes↗
PubMed1990

Detection of ferryl myoglobin in the isolated ischemic rat heart.

Reflectance spectroscopy was utilized to monitor the oxidation states of myoglobin (Mb) in isolated, buffer-perfused rat hearts. Hearts were subjected to 30 min global, no-flow ischemia, followed by reperfusion under anoxic conditions. The addition of Na2S to the buffer at reperfusion permitted the detection of ferryl myoglobin (MbIV) as its sulfmyoglobin derivative. The accumulation of MbIV was prevented by addition of ascorbic acid (1 mM), ergothioneine (2 mM), or desferal (1 mM) to the buffer prior to ischemia. Ascorbate and other agents have been previously shown to serve as one-electron reductants of MbIV. We propose that during the early phases of ischemia, deoxymyoglobin is oxidized to MbIV by residual H2O2. It also seems reasonable that the peroxidative activity of Mb(IV), during oxygenated reperfusion, might lead to cellular damage if this hypervalent form of Mb is not reduced.

Animals↗