Total synthesis of orellinine,a minor toxic component of the fungusCortinarius orellanus fries

Summary The 3,3,4,4-tetrahydroxy-2,2-bipyridyl-N-oxide has been synthesized by dealkylation of the corresponding tetramethyl derivative. The chemical properties of this compound are identical to those reported for the minor fungal toxin ofCortinarius orellanus, orellinine.This work is part of the Tesi di Laurea of Miss Cinzia Pierucci.     

Synthesis of dinucleoside phosphates by reaction of 5′-chloro-5′-deoxynucleosides with nucleotide anions

Zusammenfassung Uridylyl-(3–5)-adenosin und Uridylyl-(3-5)-ionosin wurden durch Umsetzung eines passenden 5-chloro-5-deoxy-2, 3-O-isopropylidene-Nukleosids mit Uridin-3-phosphat synthetisiert.     

Über das Vorkommen verschieden substituierter Chalkone während der Mikrosporogenese beiTulipa

Summary During the development of anthers inTulipa cv. Apeldoorn the following chalcones were isolated: 2, 3, 4, 4, 6-pentahydroxychalcone as the main component and 2, 4, 4, 6-tetrahydroxy-3-methoxychalcone as well as 2, 4, 4, 6-tetrahydroxychalcone in a very small amount.

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Die Untersuchungen wurden mit Mitteln der Deutschen Forschungsgemeinschaft unterstützt.     

Peroxides of diisopropylether

Zusammenfassung Stellt man 2,2-Dihydroperoxy-2, 2-Diisopropyläther nachIvanov et al. aus Isopropyläther her, so entsteht nebenbei auch noch 2, 2-Dihydroperoxy-2, 2-Diisopropyl-Peroxid. Beide Peroxide kann man papier- und dünnschichtchromatographisch nachweisen und mit präparativer Dünnschichtchromatographie rein isolieren.     

Hotspots of homologous recombination

Homologous recombination occurs at higher than average frequency at and near hotspots. Hotspots are special nucleotide sequences recognized by proteins that promote, directly or indirectly, a rate limiting step of recombination. This review focuses on two well-studied examples, the Chi sites of the bacteriumEscherichia coli and the M26 site of the fission yeastSchizosaccharomyces pombe. Chi, 5 G-C-T-G-G-T-G-G 3, is recognized by the RecBCD enzyme, which nicks the DNA near Chi and produces a 3-ended single-stranded DNA tail; this tail is a potent substrate for homologous pairing by RecA and single-stranded DNA binding proteins. M26, 5 A-T-G-A-C-G-T 3, is recognized by a heterodimeric protein and stimulates, by an as-yet-unknown mechanism, meiotic recombination at and near theade6 gene. Additional hotspots in bacteria, fungi, and mammals enhance recombination directly or indirectly via a variety of mechanisms. Although hotspots are widespread among organisms, the biological role of their localized enhancement of recombination remains a matter of speculation.     

The effect of cyclic N-2-O-dibutyryl-adenosine-3′, 5′-monophosphate on neuromuscular transmission and concentration of glycogen in the isolated phrenic nerve-diaphragm preparation of the rat

Résumé Le dérivé dibutyrique du 3, 5-AMP cyclique potentialise les contractions du diaphragme provoquées par stimulation électrique indirecte, alors que l'application du 3,5-AMP cyclique n'a pas un tel effet. D'autre part, ce dérivé diminue le taux de glycogène du diaphragme, ce qui n'est pas le cas pour le 3,5-AMP cyclique.     

Cyclic AMP and cyclic GMP in rats paw edema by prostaglandins

Summary Experimental results indicate that rat's paw oedema development by PGs is inhibited by 35 AMP and increased by 35 GMP. This research confirms the opposite effect to that of cyclic nucleotides. The respective behaviour of 35 AMP and 35GMP in their primary oedema-induced activity is discussed.We gratefully acknowledge the technical assistence of Mr.Sauro Pellegrini.     

Enhancement of anaphylaxis of isolated smooth muscle by adenosine phosphates and inhibition of anaphylactic mechanisms by adenosine-3′,5′-cyclic monophosphate

Zusammenfassung Zyklisches 3,5-Adenosinmonophosphat hindert in vitro die Anaphylaxis des glatten Muskels vom Meerschweinchenuterus, während Adenosin und Adenosin-5-Monophosphat die anaphylaktische Reaktion erhöhen.     

Interaction of polyene antibiotics and serum lipoproteins

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Isoforms of baker's yeast transketolase

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The selective esterification of the 5′-hydroxyl of thymidine

Zusammenfassung Ein einfacher Weg zur selektiven Esterbildung mit der 5-Hydroxylgruppe von Thymidin wird beschrieben. Beispiele: Thymidin-5-phosphat, Thymidin-5-sulfat und Thymidin-5-trichloracetat.     

A new synthetic method of coumestan derivatives

Zusammenfassung Die Synthese von 7-Hydroxy-5,6-dimethoxybenzofurano[3,2:3,4]coumarin aus 7,2-Dihydroxy-oder 7-Benzyloxy-2-hydroxy-4,5-dimethoxyisoflavon wird beschrieben.     

Zur Synthese des Batrachotoxinins: Synthese von 3β-Acetoxy-16β, 20β-dihydroxy-4′-methyl-18-nor-5β, 14β-pregnano[13,14-f]hexahydro-1′,4'-oxazepin-3′-on(20a)

Summary The synthesis of 3-acetoxy-16, 20-dihydroxy-4-methyl-18-nor-5, 14-pregnano[13,14-f]hexahydro-1, 4-oxazepin-3-one (20a) is described.     

Microbiological assay of cyclic 3′, 5′-AMP

Zusammenfassung Es wird ein mikrobiologisches Testverfahren beschrieben, mit dem sehr geringe Mengen von zyklischem Adenosin 3, 5-monophosphat quantitativ nachgewiesen werden können.     

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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The synthesis of a natural dinucleoside phosphate derivative with the aid of a purine cyclonucleoside

Zusammenfassung Die Behandlung von 8-5-Anhydro-8-mercapto-2-o-mesylguanosin mit (1,2 Äquivalent) Tributylammonium-uridylat in siedendem DMF lieferte das Dinucleosidphosphat Uridyl-(3-5)-8-mercapto-2-o-mesylguanosin. Weitere Behandlung mit Raney Ni führte zum Uridyl-(3-5)-2-o-mesylguanosin.     

The syntheses of axillarin and its related compounds

Zusammenfassung Axillarin (5, 7, 3, 4-Tetrahydroxy-3,6-dimethoxyflavon). 5,3,4-Trihydroxy-3,6,7-trimethoxyflavon und 5,7,3,4-Tetrahydroxy-3,8-dimethoxyflavon wurden synthetisiert.     

N,N′-di(piperidino-methyl)-3,3′-diindolyl-methane (DIM), a diindolylmethane derivative of neuroplegic action

Zusammenfassung Ein neues Diindolyl-methan-derivat, das N, N-di(piperidino-methyl)-3, 3-diindolyl-methan, wurde synthetisiert; es verursacht im Tierversuch schon in Dosen von 3–5 mg/kg einen langanhaltenden zentralen Depressoreffekt.     

Structural characteristics of the carotenoids binding to the blue carotenoprotein fromProcambarus clarkii

Summary A blue carotenoprotein from the crayfishProcambarus clarkii was extracted and purified. This carotenoprotein contains the carotenoid astaxanthin as a prosthetic group. In the present work we have identified by reconstitution, after removing the native carotenoid, some characteristics of the carotenoids that could bind to the apoprotein. The carotenoid must have two oxo groups at positions 4, 4 and two hydroxyl groups at positions 3, 3 the hexagonal or pentagonal end structure being indifferent. It has been proved that changes in the polyene chain structure such as triple bonds destroy this binding capacity.