Zur Stereochemie der Propandioldehydrase-Reaktion

Summary Propanedioldehydrase is shown to convert both (+)-(S)-2-²H-propanediol,3, and (–)-(R)-1-²H₂-propanediol,5, to specimens of deuterated propion-aldehyde, for which the (S)-configuration has been established. Thus, in the propanedioldehydrase reaction migration of hydrogen atoms from C–1 to C–2 always occurs with inversion of configuration.     

ZNS-aktive Phenylpropylamine vonCatha edulis FORSK. (Celastraceae) kenyanischer Herkunft

Summary The phenylpropylamine fraction ofCatha edulis FORSK. grown in Kenya has been investigated. The major components have been found to be (S)-(–)--aminopropiophenone (1), (+)-norpseudoephedrine (2) and(–)-norephedrine (3). Quantitative ratios of1, 2, 3 in tissues of different age are discussed.

---

ZNS-aktive Phenylpropylamine vonCatha edulis FORSK. (Celastraceae) kenyanischer Herkunft

     

Further perhydroazulene diterpenes from marine organisms

Summary 3 novel diterpenes,4–6, having the perhydroazulene skeleton already found in pachydictiol A (1) and dictyol A (2) and B (3), have been isolated from both the digestive gland of Aplysia depilans and algae of the family Dictyotaceae.     

Pectinoacetals A-C: novel sterol hemiacetals from the gorgonianCtenocella pectinata

Three polyhydroxylated sterol hemiacetals, pectinoacetals A-C (1–3) have been isolated as their acetyl derivatives (4–6) from the acetic anhydride treated organic extract of the Indo-Pacific gorgonianCtenocella pectinata. These natural products were found to undergo very rapid epimerization at the C-18 chiral center and thus exist only as an equilibrium mixture of two diastereomers. The structure assignments are based on spectral studies and chemical modifications of the natural products.     

Inhibitory effect of flavonoids on DNA-dependent DNA and RNA polymerases

Summary Flavonoids, (–)-epigallocatechin (1), myricetin (2) and quercetin (3), were investigated for inhibitory effects onE. coli DNA polymerase I and T7 bacteriophage RNA polymerase. In both DNA and RNA synthesis,1 and3 inhibited enzyme reactions by non-competitive and mixed type inhibition respecitively, with regard to template DNAs. Myricetin (2) inhibited DNA and RNA polymerase reactions by mixed type and competitive type inhibition, respectively, with template DNAs. It was suggested that2 interacts with covalently closed/circular DNA.     

Evidence of a direct action of triiodothyronine (T3) on the cell membrane of GH3 cells: an electrophysiological approach

Summary Electrophysiological experiments demonstrate that triiodothyronine (T₃) exerts a direct effect on the membrane of a strain of cultured rat pituitary tumor cells, GH₃/B₆. These cells respond to pressure application of T₃ (2–5 nl, concentration 1·10^–10 M) with an increase in the membrane resistance (R_m) and a hyperpolarization. Spontaneously firing cells become silent.     

A potent attractant of zoospores ofAphanomyces cochlioides isolated from its host,Spinacia oleracea

A highly potent attractant of zoospores ofAphanomyces cochlioides, a causal fungus of the root rot disease of spinach (Spinacia oleracea), was isolated from spinach roots, and its structure was determined by spectroscopic evidence and chemical synthesis as cochliophilin A (5-hydroxy-6,7-methylenedioxyflavone,1). A chromosorb particle prepared by soaking in solution of1 showed a potent attracting activity toward the zoospores using concentrations of1 above 10^–9 or 10^–10 M.     

Prostaglandin A2 (PGA2) increases the coronary vascular resistance in the guinea-pig isolated heart preparation

Summary Prostaglandin A₂ (PGA₂) in concentrations of 1.5·10^–8 to 3·10^–6 M was found to produce concentration-dependent increase in the coronary vascular resistance of the guinea-pig isolated heart without alterations in myocardial contractile force and oxygen consumption.Supported by the Deutsche Forschungsgemeinschaft.     

Synsthesis and RES-stimulating activity of bacterial cell-wall peptidoglycan peptides related to FK-156

Summary The bacterial cell-wall peptidoglycan peptides and related compounds coupled with some fatty acids were synthesized, and their immunostimulating property was examined by carbon clearance assay. All the new compounds (2–6) proved to possess significant potencies superior to that of FK-156 (1).Acknowledgment. We are grateful to Dr J. Mori and his coworkers for the biological assays.     

MethylTrans-monocyclofarnesate from the spongeHalichondria panicea

Riassunto L'estere metilico dell'acidotrans-monociclofarnesico (5) è stato ora isolato dalla spugnaHalichondria panicea. Il suo rinvenimento nello stesso organismo, dal quale erano state isolate precedentemente le paniceine. (1–3), supporta l'ipotesi che la parte sesquiterpenoidica di quest'ultime si origini biogeneticamente da un precursore monociclofarnesilico.     

Caclium causes the biphasic dose-response curve for pancreatic amylase secretion

Summary High concentrations of bethanechol (10^–4 to 10^–3 M) were effective stimulants of amylase secretion from the mouse pancreas if incubations are performed in low [ca²⁺] (0.1 mM) solutions but not if normal Krebs solution (2.56 mM Ca²⁺) was used. This inhibitory effect of Ca²⁺ at high secretagogue concentrations did not appear to be mediated through the microtubules or microfilaments.     

Abbau von Quarz mit Brenzkatechin

Summary Fine divided HF-etched quartz was dissolved in a 0.2M solution of pyrocatechol at pH 9.6. Between 17 and 40 °C the dissolution rate (v _s ) follows the equation: logv _s =0.0295 T-20.87 At 25 °Cv _s amounts to 0.8 · 10^–12 g cm^–2 sec^–1. With several phenols the dissolution rate of quartz decreases in the order: pyrocatechol > pyrogallol > 2, 3-dihydroxynaphthalene.     

Aluminum-triggered structural modifications and aggregation of β-amyloids

We investigated the structural effects induced by Al³⁺ on different β-amyloid (Aβ) fragments at pH 7.4 and T= 25°C, with particular attention given to the sequences 1–40 and 1–42. Al³⁺ caused peptide enrichment in β sheet structure and formation of solvent-exposed hydrophobic clusters. These intermediates evolved to polymeric aggregates which organized in fibrillar forms in the case of the Al³⁺-Aβ_(1–42) complex. Comparative studies showed that Zn²⁺ and Cu²⁺ were much less efficient than Al³⁺ in stimulating the spontaneous aggregation/fibrillogenesis of Aβs. Studies with liposomes as membrane models showed dramatic changes in the structural properties of the lipid bilayer in the presence of Al³⁺-Aβ complexes, suggesting a major role of Al³⁺ in Aβ-induced cell dysfunction. Al³⁺ effects were abolished by desferrioxamine mesylate (DFO) only in solution. We concluded that, in vivo, DFO may act as a protective agent by preventing or reverting Aβ aggregation in the extracellular spaces.Received 29 March 2005; received after revision 10 May 2005; accepted 25 May 2005     

Ein bicyclischer Abkömmling von (−)-longifolen ausHelminthosporium sativum undH. victoriae

Summary (–)-Longifolene,4, and a new secolongifolane derivative, shown to possess structure5, have been isolated fromHelminthosporium sativum andH. victoriae.     

Zur Methodik der Artefaktausschaltung bei Anwendung von Diazoniumsalzen in der Histochemie (Phosphatasen,Esterasen usw.)

Summary A post-incubation with 1% sulfanilic acid solution in 10% CH₃COOH (approx. 2–10 min) or 5–10% potash alum or 0.5 mol AlCl₃ in 0, 1n HCl-after the histochemical reaction with diazonium salt-prevents N₂ formation. This gas originates from decomposition of tissue adsorbed diazonium salt which occurs after mounting in glycerin jelly. The inhibition of diazo-group disintegration depends, in the case of sulfanilic acid, on the formation of a diazoamino compound or double salt production with aluminium ions in the case of AlCl₃.     

Epicatechin can cause the seedling growth inhibitor,nagilactone E,to induce growth stimulation

Summary A possible new role for the flavonoid (–)-epicatechin (II) is described. It has no growth effects on its own, but when it is added to lettuce and rice seeds together with the known seedling growth inhibitor nagilactone E (I), the growth inhibitor activity ofI can cease and growth stimulation can be observed.     

The effect of perchlorate ion and some pharmacological agents on the sensitivity of the frog (Rana pipiens) rectus abdominis to acetylcholine

Zusammenfassung Die Reaktion des mit Eserin vorbehandelten musculus rectus abdominis des Frosches auf Acetylcholin liess sich durch Oxotremorin (2.0·10^–5 M), Arecolin (2.0·10^–5M), Aceclidin (1.0·10^–4 M) und Carbachol (2.0·10^–7 M) verstärken, während Atropin (1.0·10^–5 M) hemmend wirkte. Perchlorationen in Konzentrationen über 2 · 10^–4 M sensibilisierten den Froschmuskel erheblich und reduzierten die Grenzdosis, bei der eine Potenzierung durch Substanzen mit muskarinähnlicher Wirkung beobachtet wird. Alle beschriebenen Reaktionen liessen sich durch Gehirnextrakte verstärken, in denen zuvor Acetylcholin durch Kochen in alkalischer Lösung zerstört worden war.

---

---

This work was supported by NIH Grants No. NB 03007 and No. 5-F1-GM-22,905.     

Fe(II)-induced decomposition of epidioxides. A chemical model for prostaglandin E,prostacyclin and thromboxane biosynthesis

Summary A chemical model for biosynthesis of PGE, PGX and the thromboxanes from the prostaglandin endoperoxides is presented which is based on known reactions of other endoperoxides with the Fe(II)–Fe(III) redox system in vitro.Supported in part by USPH grant CA-13121 through the National Cancer Institute.     

Picrotoxin-diazepam interaction in a behavioural schedule of differential reinforcement of low rates

Summary In rats working in a behavioural schedule of differential reinforcement of low rates (6 or 10 sec), picrotoxin (1 mg kg^–1) decreased the number of premature responses and increased (in DRL 10 sec only) the number of rewarded responses. The effect of picrotoxin was antagonized by diazepam (2 mg kg^–1). In contrast to picrotoxin, strychnine (1.5 mg kg^–1) increased the number of premature responses.This work was supported by a grant of I.N.S.E.R.M. (ATP 39-76-71).     

Neobonellin,a new biologically active pigment fromBonellia viridis

Summary A difference of possible physiological significance is reported in the chemical nature of the green integumentary pigment of the echiuroidBonellia viridis, the proboscis of which contains the known bonellin (1, R=H) as the major constituent, while the body skin is mainly pigmented by an isoleucine conjugate, neobonellin, formulated tentatively as2 (R=H) by spectral and chemical data.A preliminary account of this work was presented at the IX Congress of Italian Society of Marine Biology, Ischia (Italy), May 19–22, 1977.This investigation was supported in part by a grant from Consiglio Nazionale delle Ricerche.