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  • 1
    ISSN: 1460-9568
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Calmodulin-like neuronal Ca2+-binding proteins (NCBPs) are expressed primarily in neurons and contain a combination of four functional and nonfunctional EF-hand Ca2+-binding motifs. The guanylate cyclase-activating proteins 1–3 (GCAP1–3), the best characterized subgroup of NCBPs, function in the regulation of transmembrane guanylate cyclases 1–2 (GC1–2). The pairing of GCAPs and GCs in vivo depends on cell expression. Therefore, we investigated the expression of these genes in retina using in situ hybridization and immunocytochemistry. Our results demonstrate that GCAP1, GCAP2, GC1 and GC2 are expressed in human rod and cone photoreceptors, while GCAP3 is expressed exclusively in cones. As a consequence of extensive modification, the GCAP3 gene is not expressed in mouse retina. However, this lack of evolutionary conservation appears to be restricted to only some species as we cloned all three GCAPs from teleost (zebrafish) retina and localized them to rod cells, short single cones (GCAP1–2), and all subtypes of cones (GCAP3). Furthermore, sequence comparisons and evolutionary trace analysis coupled with functional testing of the different GCAPs allowed us to identify the key conserved residues that are critical for GCAP structure and function, and to define class-specific residues for the NCBP subfamilies.
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  • 2
    ISSN: 1546-1718
    Source: Nature Archives 1869 - 2009
    Topics: Biology , Medicine
    Notes: [Auszug] The locus for autosomal dominant congenital stationary night blindness (adCSNB) has recently been assigned to distal chromosome 4p by linkage analysis in a large Danish family. Within the candidate gene encoding the β–subunit of rod photoreceptor cGMP–specific phosphodiesterase ...
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  • 3
    ISSN: 0075-4617
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Norlobelanidine, the Main Alkaloid from Lobelia polyphylla Hook and Arn.From the dried upper plant parts of Lobelia polyphylla Hook and Arn., crystalline norlobelanidine (1; mesoid cis-8.10-diphenyl-norlobelidiol) is isolated in ca. 1.4 per cent yield following a simple procedure and identified by spectroscopic methods (NMR and mass spectra). In the amino acid fraction, obtained from the same plant, 15 amino acids are identified. Phenylalanine, glutaminic acid and proline are the main amino acids.
    Notes: Aus den getrockneten oberirdischen Pflanzenteilen von Lobelia polyphylla Hook und Arn. wird nach einem einfachen Verfahren in ca. 1.4proz. Ausbeute kristallines Norlobelanidin (1; mesoides cis-8.10-Diphenyl-norlobelidiol) isoliert und spektroskopisch (durch NMR- und Massenspektren) identifiziert. In der aus der gleichen Pflanze erhaltenen Aminosäuren-Fraktion werden gaschromatographisch 15 Aminosäuren nachgewiesen. Die hauptsächlichen Aminosäuren sind Phenylalanin, Glutaminsäure und Prolin.
    Additional Material: 1 Ill.
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  • 4
    ISSN: 0075-4617
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Natural Products from Medicinal Plants, XVI1). - A Comparison of the NMR- and Mass Spectra of Bilobalide C15H18O8 and of the Ginkgolides C20H24O9-11Bilobalide (1) is a sesquiterpene C15H18O8 containing three γ-lactone rings and a tertiary butyl group. The constitution of 1 is closely related to that of the ginkgolides A-C (2-4) C20H24O9-11. Bilobalide (1) forms, like ginkgolide A (2), a monoacetate (1a) having a free tertiary OH group, a diacetate (1b) and an unsaturated monoacetate (6) which is formed by removal of the tertiary OH group. The NMR- and mass spectra of bilobalide (1) and its acetates 1a and 1b are discussed together with those of the corresponding derivatives of the ginkgolides 2-4. A degradation product C13H16O7 of 1 is obtained by chromic acid oxidation. - Neither bilobalide nor the ginkgolides exhibit bacteriostatic, fungicidic or carcinogenic effects.
    Notes: Bilobalid (1) ist ein Sesquiterpen C15H18O8 mit drei γ-Lacton-Ringen und einer tert.-Butyl-Gruppe. Es ist in seiner Konstitution eng verwandt mit den Ginkgoliden A-C (2-4) C20H24O9-11. Wie Ginkgolid A (2) bildet Bilobalid (1) ein Monoacetat (1a) mit freier tertiärer OH-Gruppe, ein Diacetat (1b) und daneben ein ungesättigtes Monoacetat (6), das durch Abspaltung der tertiären OH-Gruppe entsteht. Die NMR- und Massenspektren des Bilobalids (1) sowie seiner Acetate 1a und 1b werden mit denen der entsprechenden Derivate der Ginkgolide 2-4 vergleichend diskutiert. Von 1 wird durch Chromsäureoxydation ein Abbauprodukt der Summenformel C13H16O7 hergestellt. - Weder Bilobalid noch die Ginkgolide zeigen baktericide, fungicide oder cancerogene Wirkung.
    Additional Material: 9 Ill.
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  • 5
    ISSN: 0075-4617
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Condensed Ring Systems, II1). Bilobalid A, a New Sesquiterpene Obtained from the Leaves of Ginkgo biloba L. and Containing a Tertiary Butyl GroupA new sesquiterpene C15H18O8, Bilobalid A, has been isolated from fresh leaves of the Ginkgo tree. It is closely related, both in structure and properties, to the ginkgolides (diterpenes, C20H24O9-11), whose structure has been elucidated in the last few years. Like the latter, its molecule contains a tertiary butyl group, which hitherto has not been detected in other natural products.
    Notes: Aus frischen Blättern des Ginkgo-Baumes wird ein neues Sesquiterpen C15H18O8, Bilobalid A, isoliert, welches in seiner Konstitution und seinen Eigenschaften den in den letzten Jahren aufgeklärten Ginkgoliden (Diterpene, C20H24O9-11) nahesteht. Es besitzt wie diese eine tert.-Butyl-Gruppe, die in anderen Naturstoffen bisher nicht nachgewiesen wurde.
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  • 6
    ISSN: 0075-4617
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Synthesis of Natural Products, I. Synthesis of Hexahydro-5H-dicyclopenta [b,c]furan-5a(6H)-olStarting from 1-Oxo-spiro[4,4]nonan-6-ol (4a), hexahydro-5H-dicyclopenta[b,c]furan-5a(6H)-ol (6) is synthesized, which represents the main skeleton of the ginkgolides (1). Grignard reaction of 4a and 4b with chloromethyl benzyl ether and subsequent hydrogenolysis provides 1-hydroxymethyl-spiro[4,4]nonane-1,6-diols (5), which theoretically exist in four diastereomeric racemic forms (5a - 5d). Only one racemic form (5a; cis-trans) can be cyclized to 6. The cyclization is effected in absolute dimethyl sulfoxide.
    Notes: Ausgehend von 1-Oxo-spiro[4.4]nonan-6-ol (4a) wird Hexahydro-5H-dicyclopenta[b.c]furan-5a(6H)-ol (6) synthetisiert, dessen Ringsystem das Grundgerüst der Ginkgolide (1) darstellt. Aus 4a und 4b werden zunächst durch Grignard-Reaktion mit Chlormethylbenzyläther und anschließende hydrogenolytische Abspaltung des Benzyl-Restes die 1-Hydroxymethyl-spiro-[4.4]nonan-1.6-diole (5) hergestellt, welche theoretisch in 4 diastereomeren Racematen auftreten (5a - 5d). Nur ein Racemat (5a; cis-trans) kann zu 6 cyclisieren. Die Cyclisierung wird in wasserfreiem Dimethylsulfoxid durchgeführt.
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