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  • 1
    Electronic Resource
    Electronic Resource
    A model for the molecular basis of filament contractility and sliding as demonstrated by helix models (1986)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 6 (1986), S. 229-236 
    Details
    ISSN: 0886-1544
    Keywords: α-helix ; filament motility ; filament contractility ; filament sliding ; microtubules ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The twisting behavior of α helices has hardly been considered hitherto with regard to the function of proteins. The well-known electrostatic repulsion between the highly charged side chains, which depends on their interaction with ions, is absolutely connected with torsional rotations of the helix as long as its hydrogen bonds hold. This means a direct transformation of chemical into mechanical energy. However, the stability of a twisted single α helix with charged side chains is low in an aqueous environment. It may easily ball up to form a globular molecule with nonhelical regions of the polypeptide chain. This corresponds to a primitive contraction that obviously occurs with spasminlike proteins that contain strongly twisted filaments as Salisbury [J. Submicrosc. Cytol. 15:105-110, 1983] has shown. Steps that increase the stability and rigidity of α helical filaments are (1) the formation of coiled-coils, (2) self-intertwining (“telephone cord phenomenon”) or intertwining with other coiled-coils as shown with the intermediate filaments, and (3) association with cytoskeletal elements (microfilaments, protofilaments of microtubules) that contain globular subunits. These coarser elements are rotated by winding and unwinding of the smaller helical molecules and thus transmit the torsion produced in the α helices to the microscopic level by the sliding (screwing) motion and the shearing effect that is connected with the waves of a rotating helix. Particles are transported if connected to the helical side arms. Since the displacement of the side arms seems to occur along the single protofilaments of a microtubule, a rotation of these protofiiaments is suggested. The bidirectional transport of particles along single microtubules may be explained by the association of left- and right-handed helices with the protofilaments. According to the models, parallel and antiparallel sliding of neurofilaments and neurotubules is suggested.
    Additional Material: 12 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cm.970060223
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  • 2
    Electronic Resource
    Electronic Resource
    The motion mechanics of Nitella filaments (Cytoplasmic streaming): Their imitation in detail by screw-mechanical models (1981)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 1 (1981), S. 371-385 
    Details
    ISSN: 0886-1544
    Keywords: rotating filaments ; cytoplasmic streaming ; Nitella ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Our knowledge about the actin-containing characean filaments on the basis of light and electron microscopical investigations is reviewed. Dynamic filamentous networks, known already from isolated droplets, were detected in Nitella rhizoidal cells using light microscopical techniques. Earlier light microscopic observations in cytoplasmic droplets are confirmed and complemented by new model experiments with rotating helices. The motile phenomena occurring at the filament bundles (ring formation, wave propagation, particle translocation, net dynamics, rolling motions, formation of side arms) can, in this way, be imitated in detail. Thus, the concept of cytoplasmic streaming as a translocation along bundles of rapidly rotating helical filaments is supported. In order to explain unidirectional cytoplasmic streaming, a periodic winding up and unwinding of fine filaments is postulated by which ions are periodically bound and displaced. The formation of side arms which is favored during unwinding results in a screw-mechanical different behavior of the filaments in the two directions of rotation and therefore causes permanent particle transport in one direction.
    Additional Material: 15 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cm.970010308
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  • 3
    Electronic Resource
    Electronic Resource
    The mechanical behavior of doublet microtubules simulated by helical modelsThis work is a tribute to the memory of Donald P. Costello, whose observations have stimulated this work. (1986)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 6 (1986), S. 209-216 
    Details
    ISSN: 0886-1544
    Keywords: uniplanar flagella ; doublet microtubules ; doublet interaction ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The structural and mechanical properties of the helix-shaped isolated doublet microtubules described by Costello [Biol. Bull. 145:279-291, 1973], Zobel [J. Cell Biol. 59:573-94, 1973], and Miki-Noumura and Kamiya [Exp. Cell Res. 97:451-53, 1976, J. Cell Biol 81:355-60, 1979] are simulated by a left-handed superhelix model that consists of two intertwined springlike helices with a slight difference in their pitches. It is shown by combinations of two and more superhelices of this kind that the straight shape of the doublets in the axoneme is the consequence of a position-dependent mechanical coil-coil interaction between interconnected doublets whose curvatures bend against one another. A counterclockwise torsion changes the sense of the superhelix from the left-handed form with a smaller pitch (L2) to the right-handed form with a larger pitch (R3). The coil-coil interaction of L helices with R helices results in uniplanar, meanderlike shapes or in flattened helices. The one-sided distribution of L and R doublets as described for sperm axonemes by Costello [Biol. Bull. 145:279-91, 1973] may therefore be responsible for the uniplanar. meanderlike shape of these flagella.
    Additional Material: 16 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cm.970060220
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  • 4
    Electronic Resource
    Electronic Resource
    Umlagerungen vinyloger Carbonsäurechloride, XXII. Gleichgewichtseinstellung strukturisomerer (Z)-2,4-Penta-dienoylchloride durch 1,5-Pentadien-Sauerstoffverschiebung (1979)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 112 (1979), S. 2730-2740 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Rearrangements of Vinylogous Acyl Chlorides, XXII. Equilibrium between Structure-Isomeric (Z)-2,4-Pentadienoyl Chlorides by 1,5-Pentadiene-Oxygen TransferThe principle of 1,5-pentadiene-oxygen transfer, till now only confirmed for 2,4-pentadienones and 2,4-pentadienethioates, is extended to the 2,4-pentadienoyl chlorides 1 and 2. On heating 1 at 120°C an equilibrium with 30% 1 and 70% 2 is evolved. Since the mixture cannot be separated, an independent synthesis of 2 from the aldehyde 13 via the intermediates 14-17 is performed. The acyl chlorides 1 and 2 are characterized by their AlCl3-catalysed cyclisations to the cyclopentenone 3 and the 1 (4H)-naphthalenone 5, resp., and different esters and amides. By aromatizing nucleophilic substitutions of 5 some new naphthalene derivatives 6, 8, 10, and 11 are easily available.-The constants for the equilibrium 1⇄ 2 and activation parameters are determined and found to be in accordance with the values for the earlier investigated 1,5-pentadiene-oxygen rearrangements.
    Notes: Das Prinzip der 1,5-Pentadien-Sauerstoffverschiebung, dessen Gültigkeit bisher auf 2,4-Penta-dienone und 2,4-Pentadienthiosäure-S-ester beschränkt war, läβt sich auf die Pentadienoylchloride 1 und 2 ausdehnen. Bei 120°C stellt sich zwischen diesen ein Gleichgewicht mit 30% 1 und 70% 2 ein. Da das Gemisch nicht trennbar ist, wird 2 unabhängig aus dem Aldehyd 13 über die Zwischen-stufen 14 -17 synthetisiert. Die Säurechloride 1 und 2 werden durch ihre AlCl3,-katalysierten Ringschlußreaktionen zu dem Cyclopentenon 3 bzw. zu dem 1(4H)-Naphthalinon 5 und ihre verschiedenen Ester und Amide charakterisiert. Durch aromatisierende nucleophile Substitutionen an 5 sind einige neue Naphthalinderivate 6, 8, 10 und 11 leicht zugänglich.-Die Gleichgewichtskonstanten und Aktivierungsparameter für 1⇄ 2 werden bestimmt. Letztere stehen im Einklang mit den an früher untersuchten 1·5-Pentadien-Sauerstoffverschiebungen ermittelten Werten.
    Additional Material: 1 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19791120741
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  • 5
    Electronic Resource
    Electronic Resource
    Einflußparameter auf die Genauigkeit von DosierpumpenVortrag von J. Jarosch auf dem Jahrestreffen der Verfahrens-Ingenieure, 25. bis 27. Sept. 1985 in Hamburg. (1986)
    Weinheim : Wiley-Blackwell
    Chemie Ingenieur Technik - CIT 58 (1986), S. 242-243 
    Details
    ISSN: 0009-286X
    Keywords: Dosierpumpen ; Genauigkeit ; Einflußparameter ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cite.330580320
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  • 6
    Electronic Resource
    Electronic Resource
    Metallorganische Verbindungen der Lanthaniden. II. Dicyclopentadienyl(di-tert-butylphosphino)terbium, -holmium und -erbiumProfessor Bertold Reuter zum 60. Geburtstage am 30. Juli 1976 gewidmet (1976)
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 426 (1976), S. 127-130 
    Details
    ISSN: 0044-2313
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Organometallic Compounds of Lanthanides. II. Dicyclopentadienyl(di-tert-butylphosphino)terbium, -holmium, and -erbiumLithium(di-tert-butyl)phosphide reacts with dicyclopentadienylterbium or dicyclopentadienylholmium chloride under elimination of lithium chloride and formation of dicyclopentadienyl(di-tert-butylphosphino)terbium or -holmium, respectively. Dicyclopentadienyl(di-tert-butyl-phosphino)erbium is formed by the reaction of dicyclopentadienylerbium chloride with di-tert-butyl-(trimethylsilyl)-phosphine together with trimethylchlorosilane. The i.r. and 1H-n.m.r. spectroscopic data of the new compounds are given.
    Notes: Lithium(di-tert-butyl)phosphid reagiert mit Dicyclopentadienylterbium-bzw. Dicyclopentadienylholmiumchlorid unter Abspaltung von Lithiumchlorid und Bildung von Dicyclopentadienyl(di-tert-butylphosphino)terbium bzw. -holmium. Dicyclopentadienyl(di-tert-butylphosphino)erbium entsteht bei der Umsetzung von Dicyclopentadienylerbiumchlorid mit Ditert-butyl-(trimethylsilyl)phosphin unter gleichzeitiger Freisetzung von Trimethylchlorilan. Die IR- und 1H-NMR-spektroskopischen Daten der neuen Verbindungen werden angegeben.
    Additional Material: 2 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/zaac.19764260117
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  • 7
    Electronic Resource
    Electronic Resource
    Experiments Towards the Formation of 1,6-Dehydroquadricyclane and Density Functional Calculations on This and Related Molecules (1998)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1998 (1998), S. 493-500 
    Details
    ISSN: 1434-193X
    Keywords: Strained molecules ; Quadricyclanes ; Lithiation ; Density functional calculations ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: 1,6-Dibromoquadricyclane (6) was obtained from norbornadiene (11) by hydroboration, oxidation of the diol 12 to the diketone 14 and its conversion into 2,6-dibromonorbornadiene (20) using tribromodioxaphosphole 16b followed by treatment of the mixture 17/18 with potassium tert-butoxide in DMSO and photocyclization of 20. Reaction of 6 with tBuLi (2 equiv.) led to the formation of 1-bromo-6-lithioquadricyclane 7, the NMR spectra of which were observed up to 0°C. 7 did not lose LiBr to give 4, but could be trapped with H2O and chlorotrimethylsilane to give 21e (53%) and 21f (64%). Reaction of 6 with tBuLi (〉 4 equiv.) gave rise to 1,6-dilithioquadricyclane (21c), whose NMR spectra could also be recorded. 21c was converted into the corresponding 1,6-disubstituted quadricyclanes with D2O (87%), chlorotrimethylsilane (92%), dimethyl sulfate (55%), methyl chloroformate (45%), iodine monochloride (62%), and p-toluenesulfonyl chloride (48%). - Density functional calculations using the B3LYP-6-31G* level of theory showed that 1,6-dehydroquadricyclane (4) is a local energy minimum in its singlet electronic state. 4 contains a unique structure with 4 condensed cyclopropane units. The parent hydrocarbons 27 and 28, hitherto unknown, are also local energy minima in their singlet electronic states.
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  • 8
    Electronic Resource
    Electronic Resource
    2,5-dichloropentacyclo[4.3.0.02,5.03,8.04,7]non-3-ene: Generation and trapping of a homocubene and ab initio mo calculations on this and related moleculesDedicated to Prof. Dr. Rolf Huisgen on the occasion of his 75th birthday. (1995)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1995 (1995), S. 1765-1771 
    Details
    ISSN: 0947-3440
    Keywords: Pyramidalized olefins ; Homocubenes ; Dehydrohomocubanes ; Calculations, ab initio MO ; Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Reaction of bromotrichlorohomocubane 8 with MeLi in the presence of anthracene, 9,10-dimethoxyanthracene, 1,2,3-tri-methylisoindole, diphenylisobenzofuran, and 2,5-dimethyl-furan furnished Diels-Alder adducts of the title compound 2,5-dichlorohomocubene 7 in reasonable yields. Adduct 14a was dechlorinated by reduction with Na in tert-butyl alcohol to afford 14b. This compound could be selectively isomerized by AgBF4 to 20 and by the rhodium(I) complex 22 to a sensitive intermediate which could be reduced to 25. The structures of adduct 15a and of 14b were confirmed by X-ray analysis, ensuring that bridgehead olefin 7 had been trapped. Ab initio MO calculations show that 7 is lower in energy than 11 and 12. The extension of the MO calculations to all parent homocubenes (2, 3, 26, 27, 28) and to dehydrohomocubanes 6 and 29 was carried out to obtain information on their relative energies, their structures, and their singlet-triplet energy separation.
    Additional Material: 5 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jlac.1995199510247
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  • 9
    Electronic Resource
    Electronic Resource
    Ein Beitrag zum Stand der Technik der thermischen AbwasserreinigungGekürzte Fassung eines Vortrages, der am 28. Sept. 1979 auf dem Jahrestreffen der Verfahrens-Ingenieure (GVC) in Nürnberg gehalten wurde. (1980)
    Weinheim : Wiley-Blackwell
    Chemie Ingenieur Technik - CIT 52 (1980), S. 527-529 
    Details
    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: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cite.330520610
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  • 10
    Electronic Resource
    Electronic Resource
    Molecular characterization of the PEL1 gene encoding a putative phosphatidylserine synthase (1995)
    New York, NY [u.a.] : Wiley-Blackwell
    Yeast 11 (1995), S. 1223-1231 
    Details
    ISSN: 0749-503X
    Keywords: PEL1 gene ; petite viability ; phospholipid synthesis ; yeast ; Saccharomyces cerevisiae ; Life and Medical Sciences ; Genetics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: In the yeast Saccharomyces cerevisiae the PEL1 gene is essential for the viability of rho-/rhoo petite mutants, and its mutation in respiring cells results in a pleiotropic phenotype. Results of complementation analysis with different subclones of chromosomal DNA and re-sequencing of the YCL4w-YCL3w segment of chromosome III demonstrate that the coding region of the PEL1 gene corresponds to 1467 bp. The size of the PEL1 transcript in Northern blot analysis was estimated to be approximately 1·5 kb. Transcription initiation in wild-type cells was found to occur at the position -9 relative to the ATG. The PEL1 gene was moderately expressed irrespective of the state of the mitochondrial genome and the nature of the carbon sources. Disruption of the PEL1 gene was not lethal and resulted in the same phenotype as observed with the pel1 mutant, i.e. the cells were not able to survive ethidium bromide mutagenesis, were thermosensitive for growth on glucose at 37°C and failed to grow on minimal glycerol medium. Although the Pel1 protein exhibits significant similarity to a family of phosphatidylserine synthases, the disrupted PEL1 gene was not complemented by the multicopy plasmid-borne CHO1 gene encoding an essential yeast phosphatidylserine synthase. The Accession Number of the PEL1 gene in the EMBL data library is Z48162.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/yea.320111302
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