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  • Wiley  (33)
  • Wiley-Blackwell  (16)
  • 1995-1999  (25)
  • 1985-1989  (20)
  • 1955-1959  (4)
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  • 1
  • 2
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Journal of Morphology 192 (1987), S. 27-42 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The fate and possible roles of the cytoskeleton in the process of conjugation in the hyptrich ciliate Euplotes aediculatus were investigated. Following the coalescence of the plasma membranes of the conjugant cells, a fusion zone or bridge of cytoplasm contributed by both partners is constructed. The sub-alveolar microtubule layers of the vegetative cell cortex remain in place to define the fusion zone boundaries after cell union. The initial fusion zone consists primarily of featureless ground cytoplasm; soon the ground plasm becomes crowded with microtubules and anastomosing smooth endoplasmic reticulum, which become displaced only late in conjugation as the migratory pronuclei are exchanged between partners. Fusion zone microtubules, functioning in some undetermined way, may be involved in the nuclear migration. Resorption of the posterior portion of each partner's buccal apparatus results in the degradation of the component cilia within acid phosphatase-positive autophagic bodies. Silver staining for light microscopy shows that the late fusion zone contracts forward from the posterior border, then constricts to separate the conjugants. In some separating pairs remnants of a microfilamentous assembly are seen at the posterior edge of the fusion zone; the full extent of this system may be masked by partial degradation due to osmium tetroxide fixation. Treatment of conjugants for 6 hours with cytochalasin B prevents separation, possibly through inhibition of the actin-like microfilament assembly in the fusion zone. The observations and experiments favor a model of cell separation following conjugation in which the fusion zone is resorbed by motile or contractile processes occurring within or around the fusion bridge itself.
    Additional Material: 21 Ill.
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  • 3
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Journal of Morphology 192 (1987), S. 43-61 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The formation and subsequent dissolution of a common bridge of cytoplasm between conjugating ciliated protozoan cells provides an excellent opportunity to follow the dynamics of the cellular membrane systems involved in this process. In particular, separation of conjugant partners offers the chance to observe, at a fixed site on the cell surface, how the ciliate surface complex of plasma and alveolar membranes (collectively termed the “pellicle”) is constructed. Consequently, cortical and cellular membranes of Euplotes aediculatus were studied by light and electron microscopy through the conjugation sequence. A conjugant fusion zone of shared cytoplasm elaborates between the partner cells within their respective oral fields (peristomes) to include microtubules, cytosol, and a concentrated endoplasmic reticulum (heavily stained by osmium impregnation techniques) that may also be continuous with cortical ER of each cell. Cortical membranes displacd by fusion are autolyzed in acid phosphatase-positive lysosomes in the fusion zone. As conjugants separate, expansion of the plasma membrane may occur through the fusion of vesicles with the plasma membrane, presumably at bare membrane, presumably at bare membrane patches near the fusion zone. The underlying cortical alveolar membranes and their plate-like contents are reconstructed beneath the plasma membrane, apparently by multiple fusions of dense-cored alveolar precursor vesicles (APVs). These precursor vesicles themselves appear to condense directly from the smooth ER present in the fusion zone. No Golgi apparatus was visible in the fusion zone cytoplasm, and no step of APV maturation that might involve the Golgi complex was noted.
    Additional Material: 22 Ill.
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  • 4
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 9 (1986), S. 308-309 
    ISSN: 0935-6304
    Keywords: High performance liquid chromatography, HPLC ; Reverse phase ; Internal standard ; Trimellitic anhydride ; Air sample ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Additional Material: 2 Ill.
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  • 5
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Chemistry - A European Journal 2 (1996), S. 502-510 
    ISSN: 0947-6539
    Keywords: alkynes ; C-glycosides ; cobalt complexes ; cyclizations ; enzyme inhibitors ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Reaction of gluconolactone 2 with allylmagnesium bromide at low temperatures afforded ketopyranose 3, which could easily be converted into open-chain ketoses (R)-6 and (S)-6. Their reaction with lithioacetylide 9 afforded propargylic alcohol derivatives (R)-10 and (S)-10, which could not be cyclized directly to the desired C-ketosides. They were converted by standard procedures into (R)-14 and (S)-14 and then into dicobalthexacarbonyl complexes (R)-16 and (S)-16. A facile acid-catalyzed ring closure gave the desired C-ketosides (R)-18 α/β and (S)-18α/β, respectively, in different ratios. In order to demonstrate that removal of the protective groups and hydrogenation of the CC triple bond proceed smoothly, (R)-18 α was transformed into the deprotected target molecule (R)-1 α. For the assignment of the new chiral centers at C-2/2′ and at C-8, (S)-18α was transformed into azido derivative (S)-22α, which underwent intramolecular cycloaddition to afford the spiro derivative (S)-25α. Because of the conformational constraints in this molecule, unequivocal configurational assignment was possible with the help of NMR data.
    Additional Material: 1 Ill.
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  • 6
    ISSN: 1434-1948
    Keywords: Carbene complexes ; Carbyne complexes ; Asymmetric synthesis ; Carbohydrates ; Chiral auxiliaries ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Chiral carbene complexes [Cp(CO)2Mn=C(OR*)Ph] (4a-e) were prepared by reaction of [Cp(CO)2Mn=C(OAc)Ph] (2) with HOR* [HOR* = 1,2:3,4-di-O-isopropylidene-D-galactopyranose (3a), 2,3,4,6-tetra-O-acetyl-D-galactopyranose (3b), 2,3,4,6-tetra-O-acetyl-D-glucopyranose (3c), (S)- (3d) and (R)-1,2-O-isopropylideneglycerol (3e)]. The replacement of a CO ligand with PTol3 in 4a-e proceeded diastereoselectively to give [Cp(CO)(PTol3)Mn=C(OR*)Ph] (5a-e). The diastereoselectivity increased in the order a, b, c, d: de = 8% (5a), 33% (5b), 70% (5c), 〉 96% (5d). For (R)-5d the isomer with the (S) configuration at manganese (SMn) was formed predominantly. For (S)-5d, only (RMn,S)-5d was detected (de 〉 96%). Photolysis of (R)-4d in the presence of phosphites or phosphanes afforded (SMn)-[Cp(CO)(PR3)Mn=C(OR*)Ph] [PR3 = P(OPh)3 (8), P(OMe)3 (9), P(OMe)2Ph (10), P(OMe)Ph2 (11), PPh3 (12), P(C6H4Cl-p)3 (13)] with a de 〉 96%. Photolysis of (S)-4d in the presence of P(OMe)3 gave (RMn,S)-9. Complex (R)-14 [related to (R)-4d] was obtained from [Cp(CO)2Mn=C(OAc)Tol-p] and 3d. Replacement of CO by PR3 in (R)-14 gave (SMn,R)-[Cp(CO)(PR3)Mn=C(OR*)Tol-p] [R = Tol-p (15), OMe (16), C6H4Cl-p (17)] with a de 〉 96%. In solution, the PTol3-substituted complex 5d is configurationally stable whereas the P(OMe)3 complex 9 epimerizes slowly at room temperature in CH2Cl2, Et2O, and THF within about one week.
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  • 7
    ISSN: 1022-1336
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The paper describes the regioselective esterification of a glucopyranoside and glucose derivative with 11-methacryloylaminoundecanoic acid in the presence of a lipase from Candida antarctica. The obtained modified sugar derivatives 6-O-(11-methacryloylaminoundecanoyl)-1-O-methyl-α-D-glucopyranoside (3 a) and 6-O-(11-methacryloylaminoundecanoyl)-3-O-methyl-α-D-glucopyranose (3 b) were polymerized radically with AIBN as initiator.
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  • 8
    ISSN: 0947-6539
    Keywords: computer simulations ; conformations ; Lewis glycolipids ; molecular dynamics ; thioglycosides ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Several monomeric and dimeric Lewis glycolipids have been investigated by NMR spectroscopy, and structural aspects were modelled by computer. From the pseudo-C2-symmetric tetrasaccharide unit that forms the recognition domain of the Lewis Y and Lewis b antigens, a totally C2-symmetric tetrasaccharide was designed that contains the structural element common to all Lewis antigens. Finally, a model for the presentation of dimeric Lewis antigens at membrane surfaces was derived. The overall shapes of the dimeric Lewis oligosaccharides are defined by the connectivity of the sugar residues within rigid tri- and tetrasaccharide building blocks.
    Additional Material: 9 Ill.
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  • 9
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Chemie Ingenieur Technik - CIT 67 (1995), S. 1330-1332 
    ISSN: 0009-286X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Additional Material: 6 Ill.
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  • 10
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 90 (1957), S. 1153-1161 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Salze von Aminosäuren werden mit reduzierenden Zuckern in wasserfreiem Methanol umgesetzt und die Kondensationsprodukte als Metallkomplexe isoliert. Das Verfahren gestattet erstmalig die Gewinnung kristallisierter N-Glyko-side aliphatischer Aminosäuren in Form ihrer Komplexsalze. Mg-, Ca-, Fe-, Co-, Cu- und Zn-N-Glykoside von Glycin, Alanin, Glutaminsäure und Methionin werden in z. T. annähernd quantitativen Ausbeuten erhalten. Das zentrale Kation des Komplexes stabilisiert die N-glykosidische Bindung; z. B. ist der hydrolytische Zerfall des N-Glykosids in wäßriger Lösung stark verzögert.
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