Johann Sonnenbichler

Di-myo-inositol-1, 1′-phosphate: A new inositol phosphate isolated from Pyrococcus woesei

A new inositol derivative could be isolated from the Archaeum Pyrococcus woesei and identified as di‐myo‐inositol‐1,1′‐phosphate by 1H, 31P NMR spectroscopy, mass spectrometry and thin layer chromatograpy. In P. woesel, this inositol phosphate represents the dominant counterion of K+ which ranges from 500 to 600 mM. The role of the potassium salt of di‐myo‐inositol‐1,1′‐phosphate as thermostabilizer is discussed.

Activation and detoxication of aminophenols. II. Synthesis and structural elucidation of various thiol addition products of 1,4-benzoquinoneimine and N-acetyl-1,4-benzoquinoneimine

1. Nine thioethers of 4-aminophenol with beta-hydroxyethylmercaptan, ranging from mono- to tetra-substituted thioadducts, were prepared from synthetic 1,4-benzoquinoneimine and characterized by 1H-n.m.r. and u.v. spectroscopy. For each compound, extinction coefficients and pKa values of the amino group were determined. 2. Five thioethers of 4-aminophenol with glutathione (GSH) were prepared and characterized by 1H-n.m.r. and u.v. spectroscopy with their respective extinction coefficients and pKa values. Two further thioadducts were tentatively assigned by their u.v. spectroscopic properties. 3. Reaction products of 1,4-[U-14C]benzoquinoneimine and GSH were studied, indicating formation of 4-amino-2-(glutathione-S-yl)phenol, 4-amino-2,3,6-tris(glutathione-S-yl)phenol as the main products. Formation of glutathione disulphide (GSSG) was not detected. In contrast, N-acetyl-1,4-[U-14C]benzoquinoneimine was partly reduced by GSH and formed only the 2-substituted thioadduct. 4. Investigation of the product orientation in the reductive addition of GSH to 2-(glutathione-S-yl)-1,4-benzoquinoneimine and 3-(glutathione-S-yl)-1,4-benzoquinoneimine, respectively, showed that the 3-substituted derivative formed mainly the 3,5-di-substituted thioadduct, whereas the 2-substituted compound formed mainly the 2,3,6-tri-substituted thioadduct. 5. Formation of thioadducts which autoxidize markedly faster than the parent aminophenol indicates that thioether formation is not an obligatory detoxication process.

Pharmacokinetics and biotransformation of diethylene glycol and ethylene glycol in the rat

1. 14C-Diethylene glycol (DEG), administered orally to rats at 1, 5, and 10 ml/kg, gave elimination half-lives of 6, 6, and 10 h, respectively, from urinary excretion data. Half-logarithmic plots of urinary 14C excretion rates versus time indicated zero-order elimination for the first 9 and 18 h after oral doses of 5 and 10 ml of 14C-DEG/kg, respectively. 14C-DEG urinary elimination kinetics changed into first-order 6, 9, and 18 h after oral doses of 1, 5, and 10 ml/kg, with a half-life of 3 h. 2. After oral doses of 3 and 5 ml ethylene glycol (EG)/kg, half-lives of 4.5 and 4.1 h were estimated from cumulative urinary excretion data for non-metabolized EG. A half-life of 2 h was determined from half-logarithmic plots of urinary excretion rates of non-metabolized EG after the same oral doses of EG. 3. The urinary concentrations of non-metabolized DEG and its metabolite, 2-hydroxyethoxyacetic acid (2-HEAA), determined by high-resolution n.m.r. spectroscopy in the urine of rats doses with DEG were 61-68% and 16-31% dose, respectively. 4. Urinary concentrations of non-metabolized EG and its metabolite, glycolic acid (GA), determined by n.m.r., gave 62-67% for non-metabolized EG and 28.7% for GA following oral doses of EG. 5. Oxidation of DEG and EG in rats was accompanied by a change of urinary pH, reflecting metabolic acidosis. 6. Comparison of the KM for DEG oxidation in vitro by ADH with that of ethanol oxidation, showed a 680-fold difference in substrate affinity. DEG inhibited ethanol oxidation non-competitively, the Ki being 0.44 M.

Oxidative stress and plant secondary metabolism: 6″-O-malonylapiin in parsley

Abstract The major flavone glycoside in parsley leaves has been identified as 6″- O -malonylapiin. This compound as well as apiin were induced approximately

Studies on the stability and decomposition of the Hagedorn-oxime HLö 7 in aqueous solution

HLö 7, (pyridinium, 1-[[[4-(aminoarbonyl)pyridinio]methoxy]methyl]-2,4-bis-[(hydroxyimino)methyl] diiodide) has been shown to be efficacious in soman poisoning of mice, even in the absence of atropine. To assess possible risks involved in the administration of HLö 7 its degradation products were analyzed at pH 2.5 and pH 7.4, respectively. At pH 2.5, where HLö 7 in aqueous solution was assumed to possess maximal stability, the predicted shelf life (10% decomposition) was about 8 years for 10 mM solutions at 8° C. The apparent energy of activation was 117 kJ/mol. At pH 2.5, attack on the aminal-acetal bond predominated with formation of pyridine-2,4-dialdoxime, 2-cyanopyridine-4-aldoxime, isonicotinamide, and formaldehyde. At pH 7.4, primary attack on the 2-aldoxime group resulted in formation of an intermediate 2-cyano-4-aldoxime derivative which mainly decomposed into cyanide and the corresponding 2-pyridinone, 1-[[[4-(aminocarbonyl)-pyridinio] methoxy]methyl]-4-[(hydroxyimino)methyl] diiodide. In addition, liberated cyanide reacted with the intermediate 2-cyano-4-aldoxime derivative with formation of 2-pyridinone, 1-[[[4-(aminocarbonyl)-pyridinio]-methoxy] methyl]-6-cyano-4-[(hydroxyimino)methyl] diiodide. This cyanide sequestering pathway became significant only at high concentrations (10 mM) of HLö 7, and was marginal at 1 mM HLö 7.

Activation and detoxication of aminophenols. III. Synthesis and structural elucidation of various glutathione addition products to 1,4-benzoquinone

1. Four thioethers of 1,4-hydroquinone with glutathione (GSH) were prepared from 1,4-benzoquinone and characterized by 1H-n.m.r. and partly by 13C-n.m.r. spectroscopy. The structures of three additional thioethers were tentatively assigned by u.v. spectroscopy. 2. The corresponding thioethers of 1,4-benzoquinone with GSH were obtained by oxidation of the corresponding 1,4-hydroquinone thioadducts with PbO2 or potassium ferricyanide. 3. Relative redox potentials of the hydroquinone/benzoquinone thioethers were estimated by determination of their redox equilibria with benzoquinone/hydroquinone. The redox potential of the mono-substituted derivative was 30 mV lower, and that of the di-substituted derivatives 70 mV lower, than that of the unsubstituted couple, thus explaining the readiness of sequential oxidation and addition reactions of the produced thioethers. 4. By use of 1,4-[U-14C]benzoquinone the reaction products with GSH were quantified to elucidate the product orientation. As observed with 1,4-benzoquinoneimine and its thioethers, formation of GSSG was not detected at physiological pH. 5. The high susceptibility of particular thioethers of 1,4-hydroquinone towards (aut)oxidation characterizes these products as reactive intermediates rather than as definitive detoxication products.

Advances in chromatin research

Recent results in chromatin research are reviewed. The nucleosomal arrangement is described and the roles of DNA, histones and non-histones are discussed in connection with their functions.

Biotransformation of the Fungal Toxin Fomannoxin by Conifer Cell Cultures

Fomannoxin [(+/-)-5-Formyl-2-isopropenyl-2,3-dihydrobenzofurane] is a phytotoxic secondary metabolite, which is produced by the forest pathogenic basidiomycete Heterobasidion annosum during the infection process. Fomannoxin shows growth-inhibiting effects on callus and suspension cultures of conifer cells. By investigating the interaction of the phytotoxin with Pinus sylvestris cells a detoxification of fomannoxin was detected, presumably as a defense reaction of the plant cells. Undifferentiated green cell lines of Pinus sylvestris were used as target cells. To provide rac-fomannoxin as a substrate a simple method for the chemical synthesis was developed. It was found that the aromatic aldehyde group is reduced by the plant cells producing the non-toxic fomannoxin alcohol which was isolated and identified by spectroscopy. After longer incubation times, also fomannoxin acid-beta-glucoside could be isolated as another detoxification metabolite. For comparison this glucoside was also synthesized.

Concerning the specificity of histone and non-histone dissociation from calf thymus chromatin by salt

Abstract The ultracentrifugation of chromatin at high salt concentrations—often assumed to yield a complete removal of histones, leaving only non-histones bound to DNA—has been studied in detail. The proteins of the supernatant and pellet after centrifugation in 2 M NaCl were analysed qualitatively by polyacrylamide-gel electrophoresis and quantitatively by cellogel electrophoresis. Both supernatant and pellet contain predominently histones and only histone fraction F1 is absent from the pellet. The non-histone patterns of supernatant and pellet show similarities. It is shown that the sedimentation of chromatin proteins with DNA in 2 M NaCl is primarily a co-sedimentation phenomenon and is not due to their specific binding to DNA. Centrifugation of chromatin proteins in the absence of DNA yields essentially the same amount of protein in the sediment as that found after centrifugation of chromatin. The proteins found in the sediment are those with the highest tendency to aggregate, i.e. predominantly the arginine-rich histones, and, to a lesser extent, the slightly lysine-rich histones and some non-histones. This indicates that co-sedimentation is caused by aggregation of the chromatin proteins.

A cyclopentabenzopyranone produced by the fungus heterobasidion annosum in dual cultures

Abstract A crystalline compound secreted by hyphae of Heterobasidion annosum in the presence of the antagonistic fungi Radulomyces confluens, Gloeophyllum abietinum, Trametes versicolor or Nectria fuckeliana was isolated. By both spectral and X-ray structure analysis, the compound was identified as 7,8-dihydro-9-hydroxy-5,7,7-trimethylcyclopenta-(g)-2-benzopyran- 1( 6H )-one.