Hydra vulgaris ω10-lipoxygenase is used in vivo to synthesize new α-linolenic acid metabolites

Previous studies conducted in cytosolic extracts of the freshwater hydrozoanHydra vulgaris led to the finding of an abundant 11(R)-lipoxygenase catalyzing the peroxidation of polyunsaturated fatty acid (PUFAs) on the tenth carbon atom from the aliphatic end (10 peroxidation). Here we describe experiments aimed at identifying the actual metabolites generated in vivo by such enzymic activity. Homogenates ofH. vulgaris polyps were analyzed by HPLC. This showed the presence of three major components chromatographically identical to three metabolites obtained when incubating the homogenates with exogenous -linolenic acid (-LA). The presence, in extracts of polyps prelabelled with [¹⁴C]--linolenic acid, of radioactive metabolites displaying the same chromatographic properties, substantiated the hypothesis that the natural products isolated in vivo are derived from -LA. Gas chromatographic analyses revealed that this was the most abundant PUFA in both free and phosphoglyceride-bound fatty acid pools. [¹H]-NMR analysis of the endogenous substances, carried out in comparison with products obtained from exogenously incubated -LA, indicated that their structures were those of 9-hydroxy-, 9-hydroperoxy- and 9-keto-octadeca-10E-12Z-15Z-trienoic acids (9--HOTrE,-HPOTrE and-KOTrE).Hydra homogenates transformed 9--HPOTrE partly into 9--HOTrE and partly into 9--KOTrE. Chiral phase HPLC conducted on 9--HOTrE established that this metabolite was composed mostly of theR anantiomer. These observations, and the finding that the presence of exogenous arachidonic acid in incubated homogenates significantly reduces the production of -LA metabolites, provide strong evidence that these compounds are produced by an enzymic activity identical to the previously-describedH. vulgaris (R)-10-lipoxygenase. Further experiments suggested that -LA, acting as the native substrate for this enzyme, is mainly esterified on the 2 position ofHydra phosphoglycerides, and that the production of the -LA metabolites described here for the first time from natural sources, can be potentially enhanced in vivo by stimuli activating phospholipase A₂.     

A postsynaptic α, 2-receptor: The alpha-adrenergic receptor of hamster white fat cells

Summary The effects of selected -agonists and -antagonists on theophylline-induced lipolysis were investigate in isolated hamster white fat cells ₂-Agonists (tramazoline, clonidine) inhibited theophylline-induced lipolysis while an ₂-agonist (methoxamine) was without any effect. The inhibitory effect of ₂-agonists was suppressed by yohimbine (₂-antagonist), whereas ₂-antagonists were inefficient. This result implies that the -adrenergic receptor of hamster fat cells is of the ₂-type, although located postsynaptically.Acknowledgments. This work was supported by grants from CNRS (ERA 412) and DGRST (grant No. 787 1078). We thank M. Dauzats for excellent technical assistance. We thank Prof. H. Schmitt for tramazoline and AR-C 239 and for helpful discussion.     

The antifertility action of α-chlorohydrin: metabolism by rat and boar sperm

Summary The male antifertility agent -chlorohydrin (I) is metabolized by rat and boar sperm to -chloroactaldehyde (III), -chlorolactate (IV) and Cl^– and not to the proposed active metabolite, -chlorohydrin-1-phosphate (III). It is proposed that -chlorolactaldehyde is produced intracellularly by a specific enzyme and that this is the metabolite responsible for the species-specific antifertility activity of -chlorohydrin.This work was supported by The National Health and Medical Research Council of Australia.     

Volatiles associated with scolytus scolytus beetles on English elm

Summary -Multistriatin, 4-methyl-3-heptanol and-cubebene, the components of the aggregation pheromone of Scolytus multistriatus are also associated with virgin female Scolytus scolytus on English elm, Ulmus procera.We thank Dr J. F. Grove for advice and encouragement, Mrs J. Allsop for technical assistance, Dr J. W. Peacock for authentic samples of multistriatin, 4-methyl-3-heptanol and-cubebene, and the Parks and Gardens Dept., Brighton Corporation, for supplies of English elm.     

Synthese von 5α- und 5β-Androstan-17β-ol-3-on-17-acetat aus Hyodesoxycholsäure

Summary 5- and 5-androstane-17-ol-3-one-17-acetate have been prepared from 5-androstane-6, 17-diol-3-one-17-acetate by a synthesis involving directedHuang-Minlon-reduction.Separation of 5-androstane-17-ol-3-one from its 5-isomer could readily be achieved by crystallisation of their 3-ethylenketals from acetone.     

Tumor necrosis factor-α inhibits collagen synthesis in human and rat granulation tissue fibroblasts

The purpose of the study was to examine the effects of tumor necrosis factor- (TNF-) on collagen gene expression in rat and human granulation tissue fibroblast cultures. The cells were exposed to 0.1, 1, 10, or 100 ng/ml of TNF-, and the rate of collagen synthesis was measured as synthesis of protein-bound³H-hydroxyproline. Total cellular RNA was isolated from fibroblasts, and measurements of specific cellular RNAs from fibroblasts were performed by Northern blot hybridizations using³²P-labeled cDNA probes. In cultures of rat granulation tissue fibroblasts TNF- decreased³H-hydroxyproline production to about 75% of that in controls and it also decreased pro1(I) and pro1(III) collagen mRNA levels, maximally to 33% and 23% of the control levels, respectively. In cultures of human granulation tissue fibroblasts a similar inhibiting effect in the production of collagen was seen. TNF- decreased the production of³H-hydroxyproline to 56% of the control value with a dose of 100 ng/ml also having an inhibiting effect on pro1(I) collagen mRNA levels of up to 43% of the control level. However, no effect was seen on pro1(III) collagen mRNA levels.     

Antagonism of V2-receptor effect of antidiuretic hormone by atrial natriuretic peptide in man

Summary Human -atrial natriuretic peptide (h-ANP) makes the urine of dehydrated volunteers hypotonic to plasma despite high circulating concentrations of antidiuretic hormone. Urinary dilution with h-ANP also occurs in subjects receiving indomethacin. Therefore, h-ANP antagonises effects of antidiuretic hormone on distal tubular V₂-receptors in man, probably without involving prostaglandins.     

Deuterium isotope effects in the ninhydrin reaction of primary amines

Summary The rate of development of Ruhemann's purple in the ninhydrin reaction of two deuterated primary amines, -d₂-p-tyramine and -d₂--phenylethylamine, is significantly reduced It appears to be a primary isotope effect and indicates that the cleavage of the carbon-hydrogen bond at the -position is involved in the rate-determining step of the color reaction.Acknowledgements. We thank Dr A.A. Boulton for his advice and encouragement and the Canadian Medical Research Councel and Saskatchewan Health for their continuing financial support.     

Identification of 3α, 17α, 21-trihydroxy-5α-pregnane (allotetrahydro-17α-hydroxy-cortexone) and 3α,21-dihydroxy-5α-pregnane (allo-tetrahydro-cortexone) in human urine

Résumé Le 3, 17, 21-trihydroxy 5-pregnane (allo-tétrahydro-17-hydroxy-cortexone) et le 3,21-dihydroxy 5-prégane (allo-tétrahydro-cortexone) ont été identifiés dans l'urine humaine. Ces composés avaient les mêmes migrations chromatographiques avant ou après acétylation ou oxydation que les respectifs stéroïdes de synthèse.     

Conjugated terpenoid ketones: A new group of plant growth regulators

Summary ,-unsaturated terpenoid ketones have a root-inducing property on the hypocotyl cuttings ofPhaseoulus aureus. Significantly isopathcoulenone, (I) is distinctly more active in causeing rooting over IAA.Acknowledgment. The work was financially supported by the Punjab State Government, India, under the scheme Chemistry of some natural products and their significance in agriculture. The authors thank Dragoco, Holzminden, Federal Republic of Germany, for supplying the samples of monoterpenes.     

Effects of injury on the concentration ofα 1 andα 2 in the plasmas of male and female rats

Summary The effects of injury on the concentration of ₁-macroglobulin and ₂-macroglobulin in the plasmas of male and female rats has been investigated. At 5 days after injury to the male rats the ₁-macroglobulin concentration increased to 131% of its preinjury value. The ₂-macroglobulin concentration increased more rapidly to a maximum of 86 times its initial value. In the female rats ₂-macroglobulin increased only slightly and ₁-macroglobulin not at all.     

Zur Umsetzung von 3α-Hydroxy-5β-Steroiden mit Blei(IV)-acetat

Summary On treatment of 3-hydroxy-5-steroids with lead tetra-acetate formation of 3, 9-oxides is observed. The yields of this ring closure reaction decrease significantly in the order 11-keto, ^{9, 11}-ene and ring-C saturated compounds.     

Sur l'interaction de la Protamine avec des protéines sériques

Summary We noticed the formation of a precipitate on adding salmine to dilute aqueous protein solution at pH 6–7. Human and bovine serum albumin, human -globulin, and the perchloro- and sulfosalicylosoluble mucoides do not precipitate in this condition. - and -lipoproteins prepared by floatation and by Sandor's technique gave S-shaped nephelometric titration curves, as did haptoglobin, a mixture of the types Hp II-Hp II and Hp II-Hp I. In sera incubated 24 h at 37°C with protamin, the dextran sulphate test and the cetavlon test show a diminished value for -lipo- and -glucoprotein. Lipoprotein degradation is probably enzymatic in nature.     

Changes in the lumen of coronary vessels under oligemic hypotension

Conclusions The decrease of circulating blood volume, resulting in oligemic hypotension, may evoke in anaesthetized cat the active constrictory coronary vessel responses of 2 types, one occuring immediately after start of the hypotension and the other having a significantly prolonged latency.

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Single amino acid substitutions insn-glycerol-3-phosphate dehydrogenase allozymes fromDrosophila virilis

Summary The amino acid sequence was compared among the three allelic variants (allozymes) ofsn-glycerol-3-phosphate dehydrogenase inD. virilis, which are detected by one-dimensional electrophoresis. The GPDH^f variant was different from the GPDH^m by only one substitution of 68-lysine for asparagine; GPDH^s differed from GPDH^m by substitution of 127-glycine for arginine. No electrophoretically silent substitutions were found in a total of 352 amino acid residues.     

Deamination by ‘Transformed’ mitochondrial amine oxidase of the ε-amino group of lysine and selective inhibition of this reaction by β-aminopropionitrile

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Subzelluläre Verteilung der Brenzcatechinamine in Herz und Nebennieren von Meerschweinchen nach Vorbehandlung mitl-α-Methyl-Dopa

Summary -Methyl-noradrenalin synthesized after pretreatment of the guinea-pig with -methyl-dopa was found to be localized, like noradrenalin, mainly in the granular fraction 100 000g of the heart and in the fraction of the chromaffin granules of the suprarenal medulla (15000 g). -Methyl-adrenalin could not bo found.

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Ausgeführt mit Unterstützung der Deutschen Forschungsgemeinschaft.     

Differential expression and dosage compensation of theα-amylase gene inDrosphila miranda

Summary The-amylase gene ofDrosophila miranda is located on the X²-and on the neo-Y-chromosome, both developing sex chromosomes. Crosses between strains carrying different electrophoretically distinguishable alleles of the-amylase gene were performed. Females of the F₁ offspring showed the expected heterozygosity, while the males proved to be hemizygous for this locus. Only the gene on the X²-chromosome is expressed, whereas the corresponding gene on the neo-Y-chromosome is not. Estimates of the-amylase activity in crude homogenates of male and female flies suggest strongly that the-amylase gene is dosage compensated inD. miranda. In contrast to this situation, in all otherDrosophila species the-amylase allele is autosomal and hence not dosage compensated.Acknowledgments. We would like to thank Betty C. Moore, for the kind supply ofD. miranda strains. For the help and advice in the electrophoretic separation of the-amylase variants we are indebted to Dr W. Pinsker. This work was supported by a grant from the Fonds zur Förderung der wissenschaftlichen Forschung, P5413 (Austria).     

Exchange of tritium from randomly tritiated taurocholate by microbial bile salt oxidoreductases

Summary Tritium distribution on randomly labelled taurocholate (TC) was estimated at 28%, 4%, 1% and <0.5% on the hydrogens opposite the 3-, 7- and 12-OH groups and taurine moiety respectively. Anomalously,C. perfringens 3-hydroxysteroid dehydrogenase (3-HSDH) catalyzed tritium loss of 36% on formation of 7-, 12-dihydroxy-3-keto-5-cholanoate, implying additional losses of tritium at other sites by this enzyme.This work is supported by the National Cancer Institute.