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  • Inorganic Chemistry  (702)
  • Cell & Developmental Biology  (555)
  • 1980-1984  (1,257)
  • 1925-1929
  • 1983  (1,257)
Collection
Keywords
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  • 1980-1984  (1,257)
  • 1925-1929
Year
  • 1
    Electronic Resource
    Electronic Resource
    Bending patterns of chlamydomonas flagella I. Wild-type bending patterns (1983)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 3 (1983), S. 131-150 
    Details
    ISSN: 0886-1544
    Keywords: flagella ; Chlamydomonas ; motility ; flagellar reversal ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Using a uniflagellate mutant of Chlamydomonas and flash photomicrography at 300 Hz, we have obtained detailed information on the forward and reverse beating modes of Chlamydomonas flagella and on the relationship between rotation of the uniflagellate cell and the bending cycle of the forward mode. Flagella ranging in length from 5 to 15.5 μm were photographed. There is a decrease in wavelength and an increase in curvature in the principal bends when the length of the flagellum is less than the normal length of 12-13 μm, but these changes are not sufficient to maintain similarity of the bending pattern. In the reverse mode, the flagellum propagates symmetrical, planar, undulatory waves with a shear amplitude which is the same as in the forward mode: there is a 19% increase in beat frequency and a similar decrease in wave length. The reorientation of the flagellar beat direction towards the axis of the cell in the reverse mode is caused both by the decrease in asymmetry of beat and by activation of sliding in the principal bends at an earlier time in the beat cycle, relative to the time of activation of sliding in reverse bends. There are additional rare modes of beating which may be related to intermediate stages in the transition between forward and reverse beating modes.
    Additional Material: 11 Ill.
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    URL: http://dx.doi.org/10.1002/cm.970030204
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  • 2
    Electronic Resource
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    Taxol binds differentially to flagellar outer doublets and their reassembled microtubules (1983)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 3 (1983), S. 123-130 
    Details
    ISSN: 0886-1544
    Keywords: taxol ; microtubules ; flagellar outer doublets ; tubulin ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Taxol induces the in vitro assembly of calcium stable microtubules from flagellar tubulin solubilized from sea urchin (Strongylocentrotus purpuratus) sperm tail outer doublets by sonication. Assembly occurs in the presence or absence of exogenous GTP. The drug (10 μM) reduces the critical concentration of protein required for assembly to ≤0.04 mg/ml. 3H-Taxol binds specifically to both isolated flagellar outer doublets and to reassembled microtubules with calculated maximal binding ratios of 0.25 and 1.32 moles taxol/mole polymerized flagellar tubulin dimer, respectively. We suggest that the discrepancy in maximal binding ratios may result from the presence of an endogenous molecule(s) along the surface of outer doublet microtubules that restricts taxol binding to that structure.
    Additional Material: 4 Ill.
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    URL: http://dx.doi.org/10.1002/cm.970030203
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  • 3
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    Cell motility and microtubules in cultured fibroblasts from patients with Kartagener syndrome (1983)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 3 (1983), S. 185-197 
    Details
    ISSN: 0886-1544
    Keywords: dynein ; microtubules ; cell motility ; fibroblasts ; in vitro ; phagokinetic tracks ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Patients with Kartagener syndrome (KS) show defects in ciliary and flagellar movement that are usually associated with the partial or total absence of dynein side arms from axonemal microtubules. Dynein is essential for such movements, but its involvement in other cellular (particularly microtubule-related) processes is unknown. It has recently been reported that neutrophils from KS patients show impaired motility including responses to chemotactic stimuli, suggesting that dynein-like proteins may be generally involved in motile processes. In support of this, we have now found that spontaneous motility of cultured skin fibroblasts from KS patients is also markedly impaired. Three cell lines derived from skin explants of KS patients with deficient dynein side arms in nasal cilia and eight cell lines derived from normal volunteers were studied. Fibroblasts were seeded into dishes containing colloidal gold-coated cover glasses [Albrecht-Buehler, 1977], incubated for 24 h at 37°C, and the area of cell “phagokinetic” tracks determined.Each cell line studied in this manner reproducibly displayed an amount of spontaneous motility characteristic for that cell line. The mean track area (± SE) for all control cells studied was 14.6 ± 0.5 × 103μm2 whereas for KS fibroblasts was 8.7 ± 0.4 × 103μm2 (P 〈 0.001). Immunofluorescence microscopy using antitubulin and antihuman 210 K MAP antibodies revealed no differences in the staining patterns between control and KS fibroblasts. Pinocytic rates were identical, and the complement of tubulin and major microtubule associated proteins as seen on one-dimensional SDS polyacrylamide gel autoradio-graphs appeared similar for control and KS cells. Thus, the observed motility defect is probably not the result of alterations in the occurrence or distribution of microtubules or in the occurrence or binding of the major microtubule-associated proteins. This defect in cellular motility may be related to the absence of dynein or may reflect another independent cellular defect.
    Additional Material: 4 Ill.
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    URL: http://dx.doi.org/10.1002/cm.970030207
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  • 4
    Electronic Resource
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    Organization of interdoublet links in tetrahymena cilia (1983)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 3 (1983), S. 321-332 
    Details
    ISSN: 0886-1544
    Keywords: microtubule sliding ; interdoublet links ; radial spokes ; bend formation ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Ciliary axonemes from Tetrahymena extracted by KCl to remove the dynein arms reveal an orderly array of interdoublet links connecting adjacent A-B or A-A subfibers. The links repeat every 96 nm at a stable site on the A subfiber positioned near the bases of radial spokes 2 and 3. Both links and radial spokes are in lateral register across the nine successive doublets of unbent axonemes. In contrast, bent axonemes or those reactivated by ATP to undergo partial sliding disintegration exhibit systematic displacement of the interdoublet links. The links show no evidence of having elastic or other extendable properties and, therefore, must have undergone intermittent attachment with nonstructural binding sites on the adjacent subfiber. These observations suggest a more dynamic role for the interdoublet links in ciliary motion than previously has been envisioned.
    Additional Material: 6 Ill.
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    URL: http://dx.doi.org/10.1002/cm.970030404
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  • 5
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    Microtubule-containing detergent-extracted cytoskeletons in sea urchin eggs from fertilization through cell division: Antitubulin immunofluorescence microscopy (1983)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 3 (1983), S. 213-226 
    Details
    ISSN: 0886-1544
    Keywords: microtubules ; fertilization ; cell division ; sea urchin ; cytoskeleton ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The microtubule-containing structures that appear in eggs during fertilization and cell division in the sea urchins Lytechinus variegatus and Arbacia punctulata were detected by antitubulin immunofluorescence microscopy of detergent extracted cytoskeletal preparations. The extraction buffer, which is composed of 0.55 mM MgCl2, 10 mM EGTA, 25 mM MES, 25% glycerol, 1% Nonidet P-40, and 25 μM PMSF, pH 6.7, allows for dramatically improved fluorescent images compared to those obtained using conventional staining procedures, with residual background staining being reduced to near zero.The immunofluorescent images obtained using this technique provide information on several motile events that occur during the first cell cycle. This technique demonstrates that all of the cytoplasmic microtubules are associated with the incorporated sperm's centrioles during female pronuclear migration. This changes during the centration of the male and female pronuclei at which time a monastral array of microtubules forms in the egg's cytoplasm. A large proportion of the monastral microtubules do not appear to be associated with the centrioles. At prophase and early metaphase, the centrioles are the dominant microtubule organizing centers (MTOCs) consistent with mitotic theories that the kinetochore catches, but does not initiate, microtubules. Observations of intercentriolar distances show that there are three stages of pole separation during the first cell cycle. The initial separation occurs during pronuclear centration, the second during the streak stage, and the final one during the late stages of mitosis. At telophase, polar microtubules appear to extend into the cortex supporting the cell surface at all regions except the presumptive cleavage site.
    Additional Material: 7 Ill.
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    URL: http://dx.doi.org/10.1002/cm.970030303
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  • 6
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    Erratum (1983)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 3 (1983), S. 281-282 
    Details
    ISSN: 0886-1544
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cm.970030308
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  • 7
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    Differential response to contact during embryonic nerve-nonnerve cell interactions (1983)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 3 (1983), S. 307-320 
    Details
    ISSN: 0886-1544
    Keywords: contact inhibition ; contact guidance ; growth cones ; cell-cell interactions ; neuronal contact behavior ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The outcome of contact interactions involving neurons and nonneurons varies depending on the cell types involved. When neuronal growth cones from either ciliary (motor) or dorsal root (sensory) ganglia directly contact the lamellipodium of an embryonic heart fibroblast, both neurite elongation and fibroblast locomotion are inhibited. This occurs in spite of the fact that cell-surface activity in both cells continues unabated. Such contact inhibition is not observed when homologous ganglionic nonneurons are involved in the interaction. In fact, these cells become intimately associated with growth cones and/or neuritic shafts as a result of the contact. The detailed nature of the respose to contact exhibited by nerves and nonnerves varies not only with cell type but also with the portion of the cell involved in the contact. Growth cone filopodia tend to actively palpate the fibroblast surface, whereas spread regions, termed “veils,” form areas of apposition with fibroblast lamellipodia. This latter situation resembles the “typical” contact inhibition of locomotion that occurs following embryonic heart fibroblast-fibroblast interactions. Growth cones also frequently exhibit contact guidance when interacting with nonruffling lateral surfaces of heart fibroblasts.
    Additional Material: 8 Ill.
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    URL: http://dx.doi.org/10.1002/cm.970030403
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  • 8
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    Preface (1983)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 3 (1983), S. ix 
    Details
    ISSN: 0886-1544
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cm.970030502
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  • 9
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    Abstracts (1983)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 3 (1983), S. 699-719 
    Details
    ISSN: 0886-1544
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
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    URL: http://dx.doi.org/10.1002/cm.970030534
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  • 10
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    Masthead (1983)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 3 (1983) 
    Details
    ISSN: 0886-1544
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cm.970030201
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  • 11
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    Structural connections of the muscle-tendon junction (1983)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 3 (1983), S. 431-438 
    Details
    ISSN: 0886-1544
    Keywords: myotendinous junction ; laminin ; type IV collagen ; heparan sulfate proteoglycan ; alpha actinin ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The muscle-tendon junction of murine skeletal muscles has been analyzed by a variety of extraction techniques, by myosin subfragment-1 binding experiments, and by ultrastructural immunocytochemistry. The results indicate that the muscle-tendon junction is composed of four distinct domains: an intracellular domain, the internal lamina; a domain connecting the internal lamina with the lamina densa of the external lamina, the connecting domain; the lamina densa; and a domain which attaches the lamina densa to the collagen fibers, the matrix. Each of these domains is distinct with respect to position, three-dimensional organization, and molecular composition, and is therefore considered to have a unique role in the transmission of contractile force.
    Additional Material: 11 Ill.
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    URL: http://dx.doi.org/10.1002/cm.970030511
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  • 12
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    Stimulus-induced activation of the calcium-dependent protease within platelets (1983)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 3 (1983), S. 579-588 
    Details
    ISSN: 0886-1544
    Keywords: calcium-dependent protease ; contractile proteins ; platelets ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Additional Material: 3 Ill.
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    URL: http://dx.doi.org/10.1002/cm.970030524
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  • 13
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    Effects of abnormal cytoskeletal structure on erythrocyte membrane mechanical properties (1983)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 3 (1983), S. 609-622 
    Details
    ISSN: 0886-1544
    Keywords: erythrocyte membrane ; surface elastic shear modulus ; membrane viscosity ; hereditary disorders of blood ; membrane yield ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Measurements of the mechanical properties of the erythrocyte membrane provide a direct assessment of the proper function of its structural components. To assess the effects of alterations in molecular structure on membrane mechanical properties, measurements have been performed on cells from six individuals whose membranes contain inherited, biochemically characterized structural defects. Because the contribution of the memmbrane skeleton to the mechanical behavior of the membrane is most evident in shear deformation, mechanical experiments were performed to measure the material constants which characterize the response of the membrane to shear force resultants. The surface elastic shear modulus characterizes the elastic response of the membrane; the yield shear resultant is the maximum shear force resultant which the membrane can support elastically; and the plastic viscosity coefficient characterizes the rate of membrane deformation when the elastic limit has been exceeded.Generally, it was found that when the molecular defect is found to occur in a region of the skeleton which is stress-supporting, the maximum elastic strength of the membrane is reduced. However, the magnitude of the reduction can be quite different for membranes having similar or even identical defects. In some cases the differences can be attributed to the removal of the most fragile cells of the population by the spleen, but other results indicate that the biochemical description of the defects may be incomplete. These results emphasize the need for further refinements both in the biochemical characterization of membrane skeleton structure and in the description and measurement of membrane mechanical properties.
    Additional Material: 7 Ill.
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    URL: http://dx.doi.org/10.1002/cm.970030526
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  • 14
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    Spectrin, fodrin, and TW260/240: A family of related proteins lining the plasma membrane (1983)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 3 (1983), S. 671-682 
    Details
    ISSN: 0886-1544
    Keywords: actin ; cytoskeleton ; membrane connections ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Recently, molecules highly related to erythrocyte spectrin have been identified in nonerythroid cells. Here we summarize our current understanding of these molecules and suggest a model for their organization. Significant differences exist between this family of proteins isolated from mammalian cells and avian cells, and this may explain the variability in antibody preparations as well as differences in peptide maps of these subunits which have been reported. We have prepared antibodies specific for the variant subunits of the spectrinlike proteins fodrin, spectrin, and TW260/240 and analyzed the distribution of these variant subunits in different chicken cell types as well as their developmental distribution in the intestine. The results suggest that fodrin is the general member of this family of proteins and can even coexist with other spectrinlike proteins in the same cells.
    Additional Material: 5 Ill.
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    URL: http://dx.doi.org/10.1002/cm.970030531
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  • 15
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    Motility of human polymorphonuclear neutrophils: Microscopic analysis of substrate adhesion and distribution of F-actin (1983)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 3 (1983), S. 31-46 
    Details
    ISSN: 0886-1544
    Keywords: polymorphonuclear neutrophils ; motility ; F-actin distribution ; adhesion ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Directed movement of polymorphonuclear neutrophils (PMN) requires cell polarization and the orderly making and breaking of cell-substrate contacts. We compared the movement of human PMN suspended from the underside of glass coverslips to that of PMN seen in “profile” on fibers, using brightfield, differential interference contrast and reflection interference microscopy. Images were recorded on film and videotape and analyzed in real time and time lapse. The distribution of F-actin was observed with image-enhanced fluorescence microscopy after staining with NBD-phallacidin.PMN exhibited two patterns of motility. Fifteen to twenty-five percent of cells moved in a low profile gliding pattern and exhibited cauded displacement of dorsal surface folds. Most PMN made progress by cycles of partial release of the lamellipodium from the substrate and anterior advance followed by arching or rolling and lamellipodial reassociation with the substrate. Cells stimulated with bacteria, casein, or chemotactic formyl peptide rarely spread on the coverglass but waved into the medium attached only by the uropod. Eventually, many detached completely from the substrate. Cells confined to the substrate surface with overlying agarose were able to locomote when confronted with these substances.F-actin was irregularly distributed in nonpolarized suspended cells but concentrated in the lamellipodium in polarized cells. As cells arched along a substrate, F-actin accumulated in foci corresponding to the substrate-PMN interface, particularly at the uropod and retraction fibrils. Conversely, cells that were physically restricted to movement in the plane of the substrate surface by overlying agarose exhibited diffuse F-actin along the entire cell. Suspended PMN polarized with formyl peptide and incubated with Con A accumulated F-actin at the uropod. These observations suggest that both PMN locomotion and the movement of Con A binding sites involve the caudad redistribution of F-actin.
    Additional Material: 9 Ill.
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    URL: http://dx.doi.org/10.1002/cm.970030104
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  • 16
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    Nocodazole pretreatment in anaphase selectively reduces anaphase B in PtK1 cells (1983)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 3 (1983), S. 79-91 
    Details
    ISSN: 0886-1544
    Keywords: mitosis ; anaphase ; microtubules ; nocodazole ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: During early anaphase PtK1 cells were briefly treated with the rapidly reversible microtubule (MT) poison nocodazole. This treatment abruptly stopped chromosome motion and effected a large decrease in spindle birefringence. On removal of the drug, chromosome to pole motion (anaphase A) returned, though at a lesser rate but not extent than untreated cells. In most cases elongation of the pole-pole distance (anaphase B) also occured, at both a rate and to an extent less than in untreated cells. During the recovery period following drug arrest spindle birefringence did not return to pretreatment levels. Electron microscopic analysis of nocodazole arrested, or arrested and released, cells revealed extensive disassembly of the nonkinetochore class of MTs (nkMTs), particularly evident in the astral region. Microtubules seen in the interzone region were largely fragments of midbody precursors. Kinetochore MTs (kMTs) appeared to be unaffected by the brief drug treatment chosen for these experiments. Analysis of MT profiles seen in transverse sections of the interzone region indicated in treated and released cells approximately 60% fewer MTs. This may suggest that chromosome motion during anaphase is not dependent on interactions between kMTs and nkMTs and separation of the spindle poles can occur in the presence of disrupted interzonal MTs.
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    URL: http://dx.doi.org/10.1002/cm.970030107
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  • 17
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    Coelomocyte motility (1983)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 3 (1983), S. 113-121 
    Details
    ISSN: 0886-1544
    Keywords: coelomocytes ; filopodia ; whole cell translocation ; video microscopy ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: We have utilized a video-enhanced contrast system coupled to a DIC-equipped microscope to examine the motility of both whole coelomocytes and individual filopodia. When the cells are left in diluted coelomic fluid, they exhibit a fibroblast-like mode of translocation across the substrate. These cells extend lamellipodia at their advancing margin and develop retraction fibers at the trailing edge. Filopodia are actively extended from the lamellipodia of the advancing margin. Cells that are washed free of the coelomic fluid and placed in an isotonic buffer lose their ability to translocate. Filopodia on these stationary cells are seen to undergo a series of waving and bending motions. These motions are rapid and result in a filopodium folding back upon itself only to reextend later. Both forms of motility are discussed in light of the existing structural and biochemical knowledge of this and other cell types.
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    URL: http://dx.doi.org/10.1002/cm.970030202
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  • 18
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    Ciliary but not saltatory movements are inhibited by vanadate microinjected into living cultured cells (1983)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 3 (1983), S. 167-184 
    Details
    ISSN: 0886-1544
    Keywords: saltatory organelle movements ; ciliary movement ; dynein ; vanadate ; microinjection ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: To test the idea that saltatory organelle movements of nonmuscle cells might be driven by microtubule-dynein interactions, we microinjected vanadate into several different types of cultured cell. Solutions of sodium metavanadate made up in a simple buffered salt solution were pressure microinjected into fully spread cells in an open-topped culture chamber placed on the stage of an inverted microscope. The cells were observed by oil-immersion phase-contrast optics and results were recorded on movie film. Vanadate, at 10-5-10-2 M, microinjected into cultured chick embryo fibroblasts, failed to inhibit organelle movements. To test the effectiveness of vanadate's inhibitory action under living cell conditions, ciliated epithelial cells were micro-injected. In these cells even the smallest microinjection of 5 × 10-5 M vanadate caused an immediate cessation of ciliary beating. Moreover, in cells that were well spread it was found that whereas vanadate, at 5 × 10-5 × 10-3M, inhibited ciliary motion, it failed to inhibit organelle saltations in the same cell. To determine whether vanadate would inhibit a living actin-myosin system, myocardial cells were also microinjected. Following microinjection of 5 × 10-5 and 5 × 10-4M vanadate a temporary tonic contraction (which also occurred following microinjection of buffer alone) was followed by regular beating. Taken together these results demonstrate that in living cell systems microtubule-dynein interactions are as sensitive to vanadate inhibition as they are in demembranated model systems, and that a working actin-myosin system in a living muscle cell does not share this great sensitivity. In light of the pronounced differential inhibitory effects of vanadate on the movements of cilia and organelles, our results suggest that saltatory organelle movements in chick embryo fibroblasts and rabbit oviduct epithelial cells are unlikely to be brought about by microtubule-dynein interactions.
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    URL: http://dx.doi.org/10.1002/cm.970030206
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  • 19
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    Masthead (1983)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 3 (1983) 
    Details
    ISSN: 0886-1544
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cm.970030301
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  • 20
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    The dynamic interrelationships of actin and vinculin in cultured cells (1983)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 3 (1983), S. 399-403 
    Details
    ISSN: 0886-1544
    Keywords: focal contacts ; cytoskeleton ; microinjection ; mobility ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The dynamic state of cytoskeletal protiens actin and vinculin was studied in living cells using microinjection of fluorescently-labeled proteins combined with fluorescence photobleaching recovery (FPR). It is shown that both proteins maintain a dynamic equilibrium between their diffusible pools in the cytoplasms and their “organized” cytoskeletal fraction. These interrelationships could be simulated in model systems consisting of isolated substrate attached membranes. It was demonstrated that fluorophore bound vinculin was incorporated into the exposed focal contacts and that this binding was largely actin independent. These results are in line with the hypothesis that local contacts induce binding of vinculin to the endofacial surface of the membranes and that this region serves as a nucleation center for the assembly of actin bundles.
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    URL: http://dx.doi.org/10.1002/cm.970030508
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  • 21
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    Organization and function of structural elements in focal contacts of tissue culture cells (1983)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 3 (1983), S. 391-397 
    Details
    ISSN: 0886-1544
    Keywords: focal contacts ; microfilaments ; microinjection ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The role of structural elements in the organization and maintenance of focal contacts was studied by microinjecting into tissue culture cells specific probes which interfere with filamentous actin or with vinculin: actin interaction. Injection of actin capping proteins from Physarum and brain resulted in breakdown of microfilament bundles starting at their distal ends and in loss of focal contacts. This process was fully reversible. Injection of a high affinity antibody against chicken gizzard vinculin led to partial breakdown of microfilament bundles concomitant with disruption of focal contacts with vinculin remaining at the plasma membrane. This process was irreversible.
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    Talin: A cytoskeletal component concentrated in adhesion plaques and other sites of actin-membrane interaction (1983)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 3 (1983), S. 405-417 
    Details
    ISSN: 0886-1544
    Keywords: vinculin ; focal contacts ; microfilaments ; transformation ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Talin is a recently identified cytoskeletal protein with a polypeptide molecular weight of 215,000 daltons. In cultured fibroblasts talin has been localized by immunofluorescence in adhesion plaques (focal contacts), in the ruffling membranes and leading lamellae of the cell periphery, and in fibrillar patterns that align with microfilament bundles and/or with cell surface fibronectin. These cellular locations suggest that the protein could function either in the attachment of microfilaments to the plasma membane or in the organization of microfilaments close to membrane attachment sites. Cell transformation by viruses such as Rous sarcoma virus disrupts the normal organization of talin, and in most transformed cells talin appears distributed diffusely through the cytoplasm. In a few cells talin is detected in doughnut-shaped aggregates, as a ring surrounding a central core of actin. The significance of these structures is uncertain, but in some cells the individual structures will condense to form much larger aggregates with a striking appearance when viewed by immunofluoresence microscopy.
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    Correlation between distribution of cytoskeletal proteins and release of alkaline phosphatase-rich vesicles by epiphyseal chondrocytes in primary culture (1983)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 3 (1983), S. 501-512 
    Details
    ISSN: 0886-1544
    Keywords: chondrocytes ; matrix vesicle formation ; actin ; tubulin ; myosin ; vinculin ; alkaline phosphatase ; immunofluorescence ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Matrix vesicles, extracellular microstructures known to eb involved in endochondral calcification, are rich in alkaline phosphatase and have been shown to contain actin. The mechanism of matrix vesicle formation in chondrocytes in not well understood. Chondrocytes from the epiphyseal growth plate, when grown in primary culture, elaborate alkaline phosphatase-rich vesciles. We examined the distribution of the cytoskeletal proteins actin, myosin, tubulin, and vinculin at various time-points during culture using indirect immunofluorescent labeling. Concomitantly, the production of alkaline phosphatase-containing matrix vesicles was also followed. Cell morphology changed noticeably at two distinct stages during the 22-day culture period: Immediately after release from the growth plate the cells were founded, but after 4 days of cultre they began to spread out and acquire irregular shapes with distinct filopodia. By 13 datsm as tge cekks attaubed confluency, they reacquired a rounded, polygonal appearance. At all time-point, tubulin was seen as a dense network of microtubules radiating from the perinuclear region throughout the cytoplasm toward the cell periphery. Initially actin was seen in filamentous from, but displayed a punctate distribution focused at contact points during the cell-spreading stage of culture. After confluency, actin was concentrated at cell-cell junctions. Initially, vinculin was diffusely distributed, but became focused in multiple adhesion plaques and at the termini of filpodia during the cell-spreading stage of culture. Following confluency vinculin became concentrated at cell-cell junctions. Myosin was observed at all time-points in small, intensely localized focal points in the cytoplasmic region of the cells and was consistently absent from the nuclear and peripheral regions. The amount of myosin in the cells increased steadily with time in culture. Elaboration of alkaline phosphatase-rich vesicles, which corresponded closely with the rounded morphology of early and late stages of culture, may be correlated with contact inhibition.
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    Calcium regulation of the actin-mediated cytoskeletal transformation of sea urchin coelomocytes (1983)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 3 (1983), S. 525-534 
    Details
    ISSN: 0886-1544
    Keywords: actin ; actin-membrane interactions ; coelomocytes ; calmodulin ; cytoskeleton ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Coelomocytes from several echinoderm species undergo an actin-mediated cytoskeletal transformation once subjected to hypotonic shock. In this study, coelomocytes from the sea urchins Lytechinus variegatus and Arbacia punctulata were induced to “transform” by treatment with 〉 5 μM of the calcium ionophore A23187 in the presence of external Ca++. The dependence of ionophore transformation on external Ca++ and the lack of chlorotetracycline staining indicates that these cells rely on external Ca++ sources. NBD-phallacidin (7-Nitrobenz-2-oxa-1,3-diazole-phallacidin) staining of lysolecithin permeabilized cells and wholemount transmission electron microscopy (TEM) show that similar reorganizations of the actin cytoskeleton take place during hypotonic shock and ionophore transformation, although actin filament bundling is less apparent in A23187-treated cells. As has been shown with hypotonic shock transformation, the ionophore elicited shape change is inhibited by anticalmodulin drugs. Greater than 10 μM concentrations of W 13 inhibit filopod formation, while this drug's less active structural analogue, W 12, exhibits no effects. W 13 also appears to disrupt actin filament-membrane associations in the cells. Fluorescent localization of calmodulin using a photooxidized derivative of trifluoperazine indicates a general cytoplasmic distribution with some concentration in filopod core bundles. Coelomocyte transformation may be an example of a cellular shape change regulated by Ca++ through the action of calmodulin modulation of actin-membrane interactions.
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    Cell surface and cytoskeletal interactions in a temperature-sensitive strain of SV40-transformed mouse fibroblasts (1983)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 3 (1983), S. 553-565 
    Details
    ISSN: 0886-1544
    Keywords: microfilaments ; cytoskeleton ; simian virus 40 ; cell adhesion ; cell surface ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: In order to assess the role of cytoskeletal structure in modulating cell surface topography during cell transformation, cytoskeletal organization of 3T3 mouse cells transformed with a tsA mutant of simian virus 40 (SV40) was studied in detail by correlative light and electron microscopy. Detergent-extracted, criticalpoint dried whole cells observed in the electron microscope were seen to contain well-organized microfilament bundles (stress fibers) traversing the longitudinal axis of cells grown at the restrictive temperature (39°C). When grown at the permissive temperature (32°C), cells prepared in this manner were not observed to contain such structures. However, when semithin sections (0.5 μm) were viewed by transmission electron microscopy at 120 kV, short microfilament bundles were seen in 32°C-grown cells. There was an alteration in the morphology of these structures at sites of attachment to the substratum (focal contacts), and they were shorter in length than microfilament bundles of 39°C-grown cells. A difference was also observed between the two phenotypes in the layer of microfilaments associated with the dorsal cell surface. Since it is this layer that directly determines cell surface architecture, it is proposed that changes in microfilament bundle-generated surface tension are responsible for alterations of this layer, leading to an altered cell surface morphology. Tension may be modified by disturbances in focal contacts (or adjacent regions) or altered actin-associated protein(s).
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    The cytoskeleton of murine leukemia virus (MuLV)-infected mouse fibroblasts as observed under varying conditions of formaldehyde fixation (1983)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 3 (1983), S. 567-577 
    Details
    ISSN: 0886-1544
    Keywords: cytoskeleton ; murine leukemia viruses ; formaldehyde fixation ; membrane permeability ; immunofluorescence ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Mouse fibroblasts chronically infected with Moloney murine leukemia virus (MuLV) were fixed using variable amounts of formaldehyde, then examined by indirect immunofluorescence light microscopy. Several antisera were employed to detect both external and internal antigens associated with the cells, eg, MuLV gp70, tubulin, vimentin, and actin. Our results indicate that the cell membranes could be partially permeabilized to IgG molecules directed against the three cytoskeletal antigens only after 3.7%, but not 1%, formaldehyde treatment. Complete permeabilization was achieved by subsequent acetone treatment of cells after 3.7% formaldehyde fixation. In such cells, normal-appearing cytoskeletal networks of microtubules and intermediate filaments were observed. Stress fibers were also seen; however, they appeared less numerous and thinner than those of uninfected mouse fibroblasts. Further, a significant amounts of F-actin fluorescence was localized in granules in the cytoplasm of infected cells. Similar observations were made using JLS-V9 mouse cells chronically infected with 334C virus, another MuLV. These results taken together suggest that subtle differences exist in the organization of actin within MuLV-infected and uninfected mouse fibroblasts.
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    Meeting highlights, critique, and perspectives (1983)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 3 (1983), S. 693-697 
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    ISSN: 0886-1544
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
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    URL: http://dx.doi.org/10.1002/cm.970030533
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    Binding of hela spectrin to a specific hela membrane fraction (1983)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 3 (1983), S. 657-669 
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    ISSN: 0886-1544
    Keywords: Hela spectrin ; membrane ; cytoskeleton ; filamin ; actin ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: From 30-40 g of Hela-S3 cells grown in suspension, 0.25-0.50 mg of spectrin has been purified by conventional biochemical procedures starting from a low ionic strength extraction at alkaline pH of crude Hela membranes. Hela spectrin consists in its native form of a tetramer α2β2 of two high molecular weight polypeptides (240,000 and 230,000 daltons). Three different populations of Hela membranes depleted of both spectrin and actin have been prepared on discontinuous sucrose gradients. Surprisingly, spectrin will reassociate with only the heavier membrane fraction. This reassociation is specific for Hela spectrin, since three other purified Hela proteins as well as human erythrocyte spectrin do not reassociate under the same conditions. This binding is not due to the presence of traces of actin still present in the membrane fraction since two Hela actin-binding proteins (filamin I and II) do not show any significant binding to this fraction. The nature of the membrane-binding site for Hela spectrin is discussed.
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    Coelomocyte spectrin (1983)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 3 (1983), S. 683-691 
    Details
    ISSN: 0886-1544
    Keywords: α-spectrin ; coelomocytes ; filopodia ; actin/membrane interactions ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: We have investigated the presence and localization of an α-spectrinlike protein and its potential role in the morphological transformation of sea urchin coelomocytes. In immunofluorescence images there is a diffuse fluorescence throughout the petaloid cytoplasm, indicating a random distribution of the spectrinlike protein prior to the transformation. As these cells form filopodia, there is a coincident appearance of a spectrinlike protein, as seen in fluorescent images, at the site of filopodial initiation. As the filopodia continue to form and lengthen, the spectrin localization parallels their development. There is a single polypeptide observed on sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) gels of whole coelomocyte lysates that cross-reacts with the anti-α-spectrin immunogen and comigrates with it at 240 kilodaltons.
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    Masthead (1983)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 3 (1983) 
    Details
    ISSN: 0886-1544
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
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    URL: http://dx.doi.org/10.1002/cm.970030101
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    Motility, cell shape, and locomotion of neutrophil granulocytes (1983)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 3 (1983), S. 47-60 
    Details
    ISSN: 0886-1544
    Keywords: neutrophil granulocytes ; motility ; locomotion ; cell-shape ; cell-substratum adhesion ; f-Met-Leu-Phe ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Activation of the motile apparatus by chemokinetic factors cannot be reliably assessed in cells that are attached to a solid substratum because motility can be totally abolished by excessive adhesion. It is however, necesary to quantify the activation of the motile apparatus in order to analyze and understand chemokinetic responses.It was the purpose of the present work to establish morphological criteria that can be used to quantify motility in nonadherent (floating) neutrophils and to predict the locomotor response under conditions of limited adhesion. The proportion of neutrophils performing crawling-like movements (polarized cells) in suspension correlates very closely with stimulated locomotion at low to optimal concentration of f-Met-Leu-Phe, ie, under conditions of limited adhesion. Reduced locomotion at supraoptimal concentrations of f-Met-Leu-Phe has also morphological correlates. The major feature is the decrease in the proportion of neutrophils performing crawling-like movements and the corresponding appearance of cells that are motile but not polarized in suspension and that do not locomote on the substratum. Concentration-dependent changes in neutrophil length and in the proportion of polarized neutrophils with and without tail were also observed. The locomotor potential of neutrophils under conditions of limited contact with the substratum can be predicted on the basis of their motile behavior, in particular the proportion of cells showing crawling-like movements, in suspension. In combination with measurements of adhesion the procedure should permit a more complete analysis of the regulation of chemokinetic responses.
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    Erratum (1983)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 3 (1983), S. 111-111 
    Details
    ISSN: 0886-1544
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
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    URL: http://dx.doi.org/10.1002/cm.970030110
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    Cytoplasmic transport in keratocytes: Direct visualization of particle translocation along microtubules (1983)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 3 (1983), S. 1-19 
    Details
    ISSN: 0886-1544
    Keywords: cytoplasmic transport ; Saltation ; microtubules ; keratocytes ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: We report the first direct demonstration that the cytoplasmic transport of organelles and vesicles (collectively called particles) takes place along microtubules. Living keratocytes from the corneal stroma of the frog, Rana pipiens, were observed with Allen video-enhanced constrast, differential interference constrast (AVEC-DIC) microscopy [Allen et al, 1981]. In sufficiently thin regions of these cells a network of linear elements was visible. When particles were observed in motion, they always moved along these linear elements. The linear elements remained intact and in focus on the microscope when lysed in a cell lysis solution that stabilized microtubules. Preparations were then fixed in formaldehyde, washed with phosphate-buffered saline (PBS), incubated with rabbit antitubulin, washed with PBS, stained with rhodamine-conjugated goat antirabbit, and washed with PBS. The extracted cells continued to remain in place and in focus on the microscope throughout these procedures. The same cells were then observed using epifluorescence optics and a silicon-intensified target (SIT) video camera. A network of fluorescent linear elements was seen to correspond in number, form, and position to the linear elements seen in the live AVEC-DIC image. Taken together, the AVEC-DIC and fluorescence microscopy observations prove that the linear elements along which particles move are microtubules (MTLEs). The observed particle speeds, pause times, and distances moved varied widely, even for the same particle on the same microtubule. Particles were also observed to switch from one microtubule to another as they were transported. The polarity of the microtubules did not seem to affect the particle direction, since particles were observed to move in both directions on the same MTLE. When not in motion these particles behaved as if anchored to the microtubules since they showed negligible Brownian motion. Finally, it was observed that an elongate particle could move onto two intersecting linear elements such that it was deformed into an inverted “Y” shape. This indicates that there may be more than a single site of attachment between the force generator and the particle.
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    Flagellar rootlets as myonemal elements for pusule contractility in dinoflagellates (1983)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 3 (1983), S. 61-77 
    Details
    ISSN: 0886-1544
    Keywords: non-actin filaments (NAF) ; flagellar rootlets ; pusule ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Flagellar rootlets play an important role in “primitive motile systems.” They are made of filaments able to contract by twisting and Ca+2 binding. The pusules of Dinoflagellates appear to be under the control of large bundles of 2.4 nm nonactin filaments that correspond to the striated rootlets of their two flagella.
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    The interaction of cAMP with modeled bull sperm (1983)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 3 (1983), S. 199-210 
    Details
    ISSN: 0886-1544
    Keywords: sperm ; flagellum ; motility ; cAMP ; freeze-thawing ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Demembranated and membrane disrupted bull sperm models exhibit an increase in motility when exposed to cAMP. Tritium-labeled cAMP was used to locate the initial site of action of cAMP in the modeled sperm preparations. cAMP did not bind selectively to the modeled cells, and the presence or absence of plasma membrane fragments on the models did not significantly alter this result. When suspension medium taken from modeled sperm preparations was subjected to gel filtration on Sephadex G25-150 columns, cAMP bound to a high molecular weight component that eluted with the void volume. The responsible binding factor is a soluble component that is released when the plasma membranes of the sperm are disrupted during the modeling procedure. To test the importance of the cAMP binding factor, modeled sperm were centrifuged, the super-natant solution was decanted, and the cells were resuspended in fresh medium. After this treat-ment the cells could be restored to motility with Mg-ATP but no longer exhibited a response to cAMP. Furthermore, addition of cAMP binding factor isolated by gel filtration partially restored the response of these sperm to cAMP. Investigation of the properties of the cAMP-binding factor have confirmed that it is specific for cAMP, with a much lower affinity for AMP and cGMP. In the pre-sence of a large excess of unlabeled cAMP the labeled complex has a half-life of approximately 1 hour. Our results indicate that the action of cAMP on the motility of modeled sperm is mediated by its attachment to a high molecular weight, soluble component of the cell cytoplasm.
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    Announcement (1983)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 3 (1983), S. 211-212 
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    ISSN: 0886-1544
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
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    URL: http://dx.doi.org/10.1002/cm.970030209
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    Dedication (1983)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 3 (1983), S. i 
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    ISSN: 0886-1544
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
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    URL: http://dx.doi.org/10.1002/cm.970030302
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    The geometry of actin filament-membrane associations can modify adhesive strength of the myotendinous junction (1983)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 3 (1983), S. 439-447 
    Details
    ISSN: 0886-1544
    Keywords: actin filament ; adhesion ; muscle ; tendon ; biomechanics ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Juctions between skeletal muscle cells and tendon collagen fibers transmit forces generated by muscle cells to the skeletal system. Since force trajectories across adhesive joints partly determine the stresses at the joint (eg, shear or tensile), the geometry of actin filament-membrane-collagen fiber associations has been modeled based on ultrastructural data, and force trajectories at the junction have thereby been established. Measurements show that in healthy twitch cells, actin filaments lie at a mean angle of 4.3° (standard deviation = 0.95°; 15 cells analyzed) to the plasma membrane. Calculations indicate that maximum isometric loading is seen by the junctional membrane almost entirely as a shear stress. In disuse-atrophied muscle cells, the mean angle between actin filaments and the membrane is 9.1° (standard deviation = 3.3°; 11 cells analyzed). The shear component of loading for the junctions of atrophied cells is only 1% less than that in healthy cells. The tensile component of the stress at atrophied junctions is more than doubled, however. These data are used to interpret patterns of myotendinous junction mechanical failure in terms of adhesive joint mechanics. An increased occurrence of failure of the atrophied junction is observed at physiological loads and can be attributed to a reduction of adhesive strength under increased tensile load component.
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    Organizational forms of actin in 13762 ascites mammary tumor cell microvilli (1983)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 3 (1983), S. 491-500 
    Details
    ISSN: 0886-1544
    Keywords: actin ; microfilaments ; oligomers ; transmembrane glycoprotein ; microvilli ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The organization of microvillus actin and its associated proteins have been investigated in sublines of mammary ascites tumors (MAT) with mobile (MAT-B1) and immobile (MAT-C1) cell surface receptors. Microvilli isolated from these sublines differ in morphology (branched for MAT-C1 versus unbranched for MAT-B1) and the presence of a 58,000-dalton polypeptide (58K). 58K is found associated with MAT-C1 microvilli, microvillar cytoskeletons obtained by nonionic detergent extractions, and microvillar membranes prepared under conditions which depolymerize actin microfilaments. By extraction with actin-stabilizing buffers (isotonic Triton-Mg-ATP) microvillar actin can be fractionated into four forms. About 40% of the actin is sedimented at low speed (7,500g, 15 min). The pellets contain microfilaments; actin and α-actinin are the predominant proteins. High-speed pellets from these low-speed supernates contain about 10% of the actin as a transmembrane complex with a cell surface glycoprotein (cytoskeleton-associated glycoprotein, [CAG] 75-80,000 daltons) in MAT-B1 cells or with CAG and 58K in MAT-C1 cells. Transmembrane complexes can be purified from MAT-B1 and MAT-C1 microvillar membranes in Triton-containing buffer by gel filtration or sucrose density gradient centrifugation. The presence of only CAG and actin in the MAT-B1 transmembrane complex strongly suggests the direct interaction of actin and a cell surface component. The high-speed supernates contain soluble actin. By gel filtration or rate-zonal sucrose density gradient centrifugation about 30% of the microvillar actin is found as small oligomers and about 10% as G-actin in this extraction buffer. We suggest that the actin-containing transmembrane complexes may serve as membrane-association sites for oligomeric actin segments and microfilaments and as initiation sites for actin polymerization.
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    Striated paracrystals that contain HMWP, the homolog of actin-binding protein and filamin from HeLa cells (1983)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 3 (1983), S. 535-543 
    Details
    ISSN: 0886-1544
    Keywords: actin-binding protein ; filamin ; HeLa cell HMWP ; myosin ; HeLa cells ; paracrystals ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: HMWP (high molecular weight protein), a high molecular weight actin binding protein, was previously isolated from HeLa cells; its physical properties, amino acid composition, and intracellular localization indicated its homology with actinbinding protein and filamin [Weihing, 1982, 1983]. We now report the identification of HMWP in striated paracrystals. Purified HMWP is incubated at 25° C and subjected to negative staining with uranyl acetate. Examination by electron microscopy reveals long, striated paracrystals formed from filaments a few nanometers in diameter that lie parallel to the long axis of the paracrystal. At intervals of about 200 nm, the filaments are crossed by granular aggregates, accounting for the striated appearance. Treatment of the paracrystals with an affinity-purified antibody to HMWP decorates the filaments; such decorations are not observed if nonimmune goat IgG or phosphate-buffered saline are substituted for the antibody. Electron microscopic and electrophoretic analysis of paracrystals sedimented onto grids by centrifugation at 864 g reveals that the grids are covered with paracrystals and the major polypeptide present on grids centrifuged in parallel is HMWP. Taken together, these data indicate that the filaments of the paracrystals contain elongated molecules of HMWP. Additional experiments are needed to decide if the paracrystals from by self-association between HMWP molecules or by association with one or more of the minor polypeptides that remain in the purified HMWP.
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    A spectrin-like protein from mouse brain membranes: Immunological and structural correlations with erythrocyte spectrin (1983)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 3 (1983), S. 635-647 
    Details
    ISSN: 0886-1544
    Keywords: brain spectrin ; actin ; immunofluorescence ; peptide mapping ; protein phosphorylation ; syndeins ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Membrane-associated mouse brain spectrin is a 972,000 Mr, 10.5S, (αβ)2 tetramer containing two ∼ 240,000 Mr subunits and two ∼ 235,000 Mr subunits. Two-dimensional [125I]tryptic peptide mapping indicates that these subunits share only limited and equivalent overlap with the α- and β-subunits of red blood cell (RBC) spectrin. Both the 220,000 Mr β-subunit of RBC spectrin and the 235,000 Mr β-subunit of brain spectrin are phosphorylated in the intact mouse. In vitro analysis suggests that both are phosphorylated by a cAMP-independent protein kinase. Antibodies against pure native mouse red blood cell spectrin cross-react with brain spectrin, and antibodies against pure brain spectrin cross-react with both the α-and β-subunits of mouse RBC spectrin. Both antibodies have been utilized to localize brain spectrin within distinct cellular entities of the mouse cerebellum. Granule cell neurons of the internal granule layer and Purkinje cell neurons demonstrated intense fluorscence of the cortical cytoplasm immediately adjacent to the plasma membrane and unstained nuclei, when either RBC or brain spectrin antibodies were utilized for staining. The molecular layer of the cerebellum stained only lightly, and oligodendrocytes and astrocytes appeared to have little fluorescence. Therefore, while brain is a tissue rich in nonerythroid spectrin, the concentration of these immunoreactive analogues is quite variable within distinct cellular entities of the cerebellum.
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    Effect of cytochalasin D on smooth muscle contraction (1983)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 3 (1983), S. 545-551 
    Details
    ISSN: 0886-1544
    Keywords: vascular smooth muscle ; contraction ; cytochalasin D ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Cylindrical segments of extraparenchymal pulmonary artery (essentially a preparation of smooth muscle with regard to contractile capability) were isolated from adult male rats. They were mounted in an isometric muscle bath in physiological salt solution (PSS) in an environment of 95% O2/ CO2. After allowing 1 h for equilibration, the maximum force generated by the tissue in response to a depolarizing solution was determined. After relaxation, vessels were incubated for 1 h in one of several concentrations of cytochalasin D (CD) (0.01, 0.05, 0.5, 1, 10 μg/ml) and the response to stimulation retested immediately after returning to PSS, and then at 30 minute intervals up to 2 h.CD inhibited the ability of vascular smooth muscle to generate force (contract) in a concentration-dependent manner. The inhibitory effect was reversible within a short period of time. Quantitative electron microscopic examination of these vessels suggested that CD disrupts the integrity of myofilaments, especially at sites of “dense bodies.” Our results indicate that a percentage of actin in smooth muscle cells is not permanently in the filamentous “F” form, but is part of the G:F actin system of the cell, labile to polymerization:depolymerization. The ability of smooth muscle cells to generate force could depend on the proper functioning of the F:G actin “treadmill”.
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    Three-dimensional organization of the platelet cytoskeleton during adhesion in vitro: Observations on human and nonhuman primate cells (1983)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 3 (1983), S. 589-608 
    Details
    ISSN: 0886-1544
    Keywords: platelet ; platelet adhesion ; cytoskeleton ; high voltage electron microscopy ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Adhesion of platelets in vitro resulted in rapid polymerization of the amorphous cytoplasmic ground substance into an organized cytoskeletal superstructure. This cytoskeleton, characterized through the use of whole-mount and stereo (3-D), high-voltage microscopy in conjunction with morphometrics and cytochemistry, comprised four major size classes of filaments organized in distinctive zones. The central matrix, or granulomere, at the center of the cell mass, was an ill-defined meshwork of 80-100-Å filaments which enshrouded granules, dense bodies, and elements of the dense tubular system as identified through peroxidase cytochemistry. Demarcasting this central matrix was a trabecular zone containing 30-50, 80-100, and 150-170 Å filaments in an open and rigid-appearing lattice. Circumscribing the trabecular zone and extending to the margins of the hyalomere was the third region, the peripheral web, in which 70-Å filaments were arranged in a tight honeycomb lattice. This organizational pattern was retained in cytoskeletons prepared by Triton x-100 extraction of the adherent cells, and was observed in basally located cells of aggregates which formed subsequent to adhesion. Our observations are consistent with biochemical studies of cytoskeletons prepared from suspended platelets and suggest a contractile protein composition for the superstructure during adhesion.
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    Spectrin and ankyrin in brain (1983)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 3 (1983), S. 623-633 
    Details
    ISSN: 0886-1544
    Keywords: spectrin ; ankyrin ; brain membranes ; spectrin subunits ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Further similarity between mammalian erythrocyte spectrin and pig brain spectrin has been demonstrated by (a) formation of hybrid molecules with brain α-chains and erythrocyte β-chains and by (b) identification of an ankyrin protein in brain membranes. Hybrid spectrin molecules prepared from brain α-chains and erythrocyte β-chains were visualized by low-angle rotary shadowing as double-stranded rods (dimers) 100 nM in length. 125I-labeled brain α-chain that was hybridized with erythrocyte β-subunit acquired ability to bind to ankyrin sites on erythrocyte membranes. 125I-labeled brain α-chain bound only to β-subunits of erythrocyte and brain spectrin following transfer of these polypeptides to nitrocellulose paper from sodium dodecyl sulfate (SDS) gels. Thus brain spectrin and mammalian erythrocyte spectrin have shared functional sites involved in association of their subunits. Additional evidence for similarity of brain and erythrocyte membranes is the finding of a 210,000 Mr membrane protein in brain that cross-reacts with erythrocyte ankyrin and has a water-soluble domain of 72,000 Mr that is produced by protease digestion. The 72,000 Mr domain of brain ankyrin has been isolated by affinity chromatography on erythrocyte spectrin-Sepharose, and was demonstrated to bind directly to erythrocyte and brain spectrin. The brain 72,000 Mr fragment has distinct peptide maps from the erythrocyte 72,000 Mr ankyrin fragment and thus is not a result of erythrocyte contamination.
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    Intracellular movement of fodrin (1983)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 3 (1983), S. 649-655 
    Details
    ISSN: 0886-1544
    Keywords: axonal transport ; lymphocyte capping ; spectrin ; fodrin ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Fodrin is an actin/calmodulin-binding protein with similarities to spectrin (erythrocytes) and TW 260/240 (brush border). It is concentrated beneath the plasma membranes of neurons and other cells. We have observed translocations of fodrin in both neurons and lymphocytes. Newly synthesized, radiolabeled fodrin moves down axons at a maximum velocity (about 50 mm/day) that is slower than the most rapidly axonally transported proteins (group I). A portion of fodrin appears to move more slowly at velocities (1-10 mm/day) resembling those of actin and myosin (group IV) and tubulin and neurofilament proteins (group V). In lymphocytes, when certain surface antigens are induced by cross-linking agents to migrate to one pole of the cell and form a cap, fodrin redistributes beneath the membrane and forms a subcap. The movements of fodrin in lympohocyte capping and in the axonal transport of group IV polypeptides have certain similarities. In both cases, the redistribution of fodrin is accompanied by concomitant redistributions of actin, myosin, and calmodulin, and both processes proceed at similar velocities. We consider the possibilities that these two processes are related, both being driven by a submembrane force-generating system comprising in part actin, myosin, and fodrin, and that fodrin serves to link various organelles or proteins to this system.
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    Effects of villin on the polymerization and subunit exchange of actin (1983)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 3 (1983), S. 151-165 
    Details
    ISSN: 0886-1544
    Keywords: actin ; villin ; fluorescence ; energy transfer ; polymerization ; microfilament ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: We have investigated the Ca2+-dependent interactions of villin, a protein of the intestinal microvillar core, with actin by monitoring resonance energy tranfer between fluorescently labeled actin subunits. In the presence of elevated free Ca2+(∼20 μM), villin affects both the nucleation and the elongation phases of actin polymerization. Consistent with previous reports, villin stimulates the nucleation process and will form stable nuclei under depolymerization conditions. Compared to the control, the net rate of polymerization is slightly inhibited at low con-centrations of villin (villin/actin ∼ 1:400) but is stimulated at higher concentrations (villin/actin 〉 1:100). Villin also significantly increases the critical concentration of actin polymerization. Addition of either villin or villin-actin complexes induces depolymerization of preassembled actin filaments. This villin-induced depolymerization is reversible upon removal of free Ca2+ or upon the addition of phalloidin. The exchange of actin subunits at steady state is inhibited at low concentrations of villin (villin/actin ∼ 1:200) but is stimulated at higher concentrations (villin/actin ∼ 1:50). None of the above effects is observed at 〈 10-8 M free [Ca2+].
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    Characterization of the chlamydomonas flagellar collar (1983)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 3 (1983), S. 273-280 
    Details
    ISSN: 0886-1544
    Keywords: Chlamydomonas flagellar collars ; Chlamydomonas cell wall ; mating in Chlamydomonas ; cell wall proteins ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The flagella of Chlamydomonas reinhardtii protrude through the cell wall via short, tunnel-like openings that are lined with 11 nm × 500 nm fibers arranged in parallel array. These cylindrical collections of fibers presumably permit free movement of the flagella within the cell wall. In this report electron-microscopic evidence is presented showing that during the initial stages of the mating reaction intact collars slip off of the ends of the flagella when cell wall loss occurs. Electrophoretic analysis of isolated collars reveals one major protein and several minor species.
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    The effects of taxol on cytoskeletal components in cultured fibroblasts and epithelial cells (1983)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 3 (1983), S. 283-305 
    Details
    ISSN: 0886-1544
    Keywords: taxol ; microtubules ; intermediate filaments ; fibroblasts ; epithelial cells ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Taxol promotes microtubule (MT) assembly in vitro and induces the reorganization of the cytoskeleton into unusual MT arrays in cultured cells. The possibility that taxol also has an indirect effect on intermediate filaments (IF) was investigated. In baby hamster kidney (BHK-21) and human skin (ENSON) fibroblasts treated with 1-10 μM taxol for 1-24 h, the drug induces changes which are similar to those produced by colchicine. These include a loss of major cellular extensions, a redistribution of organelles to a perinuclear location, and an inhibition of locomotion. Saltatory particle movements are not inhibited, however. Ruffling and filopod formation continue, indicating that cells are viable up to 24 h.Polarized light microscopy of living fibroblasts treated with taxol reveals the presence of perinuclear birefringent material which has been examined by immunofluorescence. In control cells, IF and MT radiate from a juxtanuclear region and extend to the cell periphery. In taxol-treated cells, MT and IF are excluded from cell margins, forming large central bundles.In the epithelial cell lines PtK2 and PAM, the keratin system of IF does not become redistributed; in PtK2, however, a second fibroblastlike system of IF does become redistributed to a perinuclear position during taxol treatment.Ultrastructural analyses show that taxol-treated fibroblasts contain parallel arrays of cross-bridged MT-IF as well as bundles of MT exclusive of IF. Epithelial cells contain a predominance of IF-free MT bundles which are organized into hexagonally packed arrays. In these bundles MT frequently exhibit hooks or other incomplete MT profiles and are linked by filamentous material.
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    Some lessons from the erythrocyte (1983)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 3 (1983), S. 363-366 
    Details
    ISSN: 0886-1544
    Keywords: erythrocyte ; membranes ; spectrin ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
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    A covalently cross-linked matrix in skeletal muscle fibers (1983)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 3 (1983), S. 463-483 
    Details
    ISSN: 0886-1544
    Keywords: intracellular matrix ; extracellular matrix ; covalently cross-linked matrix ; ε-(γ-glutamic) lysine bonds ; skeletal muscle ; titin ; covalently cross-linked collagen ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: When skeletal, cardiac, and smooth muscle is exhaustively extracted with a protein-unfolding reagent such as 6 M guanidine HCl and a disulfide-reducing reagent such as 5% β-mercaptoethanol, a tissue ghost remains intact and retains the characteristic shape and dimensions of the tissue before extraction. In the case of chicken pectoral muscle, the tissue ghost contains 1% of the original muscle proteins. Guanidine HCl extraction followed by collagenase treatment of glycerol-extracted chicken pectoral muscle releases a clean preparation of elongated structures containing 0.2% of the original protein and representing the covalently cross-linked remnants of the muscle fibers. The material of these muscle fiber ghosts extends throughout the interior of the cell. Antibodies raised against the tissue ghosts of smooth muscle cross-react with glycerol extracted skeletal myofibrils, forming a banding pattern which coincides with the banding pattern observed when myofibrils are reacted with antibodies against titin. Titin, a large and soluble protein found in skeletal muscle, cross-reacts with our antigizzard antibody. However, amino acid analysis of the muscle fiber ghosts indicates that titin cannot be the only subunit of the insoluble polymer, but that one or more proteins with a very high glycine and alanine content and a very low basic and acidic amino acid content must also form part of the covalently cross-linked matrix. The possibility is presented that this matrix may be the basis of the superthin 2-3-nm filaments which have been observed in a variety of cell types.
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    Invited review: Bacterial flagellar sheaths: Structures in search of a function (1983)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 3 (1983), S. 93-103 
    Details
    ISSN: 0886-1544
    Keywords: bacterial motility ; flagella ; sheathed flagella ; complex flagella ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Although bacterial flagellar sheaths were observed over 30 years ago, they may still be characterized as structures in search of a function. In addition to true sheaths, bacterial flagella may possess other adornments that cause an increase in the organelle's cross-sectional diameter. These “complex flagella” are sharply differentiated from sheathed flagella. Immunological and chemical distinctions have been found between flagellar sheaths, flagellar cores, and LPS layers inferred to be the sheath sensu stricto. Although complex flagella may serve as specific receptors for flagellotropic phages or in allowing for more efficient swimming in viscous environments, similar functions have not yet been attributed to true sheaths. It is postulated that flagellar sheaths may allow for specific interaction between a bacterium and a surface. In addition, there is a problem as to the relationship between a rapidly rotating flagellum and the sheath.
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    Chromosome movement during meiotic prophase in crane-fly spermatocytes. II. Analysis of polarization of chromosomes and their association with the nuclear envelope (1983)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 3 (1983), S. 261-271 
    Details
    ISSN: 0886-1544
    Keywords: chromosome movement ; meiosis ; spermatocytes ; prophase ; nuclear envelope ; aster ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Association of bivalent chromosomes with the astral centers and nuclear envelope was analyzed in crane-fly spermatocytes during the final hours of diakinesis. In contrast to other systems in which movement of chromosomes during diakinesis correlates with the clustering of bivalents near the astral centers, such clustering is not prevalent in crane-fly spermatocytes. Polarization indices of bivalents calculated 5 to 10 minutes before the end of diakinesis provided evidence for polarization of only a fraction of all bivalents. Similar results were obtained in a large number of fixed cells in which asters and chromosomes were preferentially stained. Ultrastructural analysis of cells in late diakinesis revealed significant contact between bivalents and the nuclear envelope in all 46 cells that were analyzed. The extent of contact in some cells was greater than in others. Sites of contact included the telomeric ends of bivalents, and in some cases the distribution of contact sites suggested the possible involvement of centromeres in chromosome-nuclear envelope association. The results are consistent with the hypothesis that a dynamic interaction between chromosomes and nuclear envelope may exist during late prophase, when the movement of chromosomes is known to occur.
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    Cell movement and its coordination in swarms of myxococcus xanthus (1983)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 3 (1983), S. 227-245 
    Details
    ISSN: 0886-1544
    Keywords: swarming ; gliding ; cooperative motility ; cell density effects ; pili ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The coordinated movement of many cells - a process called swarming - permits myxobacteria to spread rapidly over a surface. We have investigated the mechanism of swarming in Myxococcus xanthus by making time-lapse motion pictures and by measuring the dependence of cell movement and spreading rate on the concentration of cells. Motion pictures of spreading zones showed that spreading resulted from motility, not growth, and that a swarm spread outward by establishing a loose reticulum of cells, then later filling it in. The spreading rate of wildtype strains was found to be highly dependent on cell density, increasing about 8-fold as the cell density was increased from 2.5 to 200 units. Mutants swarmed if they possessed only the A-motile component (A+S-) or only the S-motile component (A-S+) of wild type (A+S+); their spreading rate increased with cell density but was always less than A+S+. Individual A+S+, A+S-, and A-S+ cells executed typical gliding movements and (when moving) progressed at approximately the same speed, as if A and S motility were different ways of engaging the same gliding machine. Photographic studies of an A-S+ strain showed that cells moved only if they were separated by less than approximately one cell length from each other. This provided further evidence that pili, which are present on A+S+ and A-S+ cells and which extend about one cell length, could be responsible for switching on movement in S-motile cells, and presumably in wild type as well.
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    Masthead (1983)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 3 (1983) 
    Details
    ISSN: 0886-1544
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
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    URL: http://dx.doi.org/10.1002/cm.970030501
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    Lateral diffusion in membranes (1983)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 3 (1983), S. 367-373 
    Details
    ISSN: 0886-1544
    Keywords: lateral diffusion ; membranes ; photobleaching ; cytoskeleton ; cell contact ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Lateral diffusion measurements, using the photobleaching techniques, have provided unique and quantitative data on the random translational motions of proteins and lipids of membranes. Proper interpretation of this body of data can yield new insight into the structure of biomembranes. A comparative review of the lateral diffusion of membrane components in artificial lipid bilayers and of the same components in natural membranes is presented to demonstrate the effects of protein concentration and peripheral constraints on lateral mobility. Recent data on the effects of cell-substrate and cell-cell contact on lateral diffusion are reviewed. Finally, some experimental perspectives are offered in terms of emerging biophysical and biological technology.
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    Quantitative analysis of axonemal bends and twists in the quiescent state of ciona sperm flagella (1983)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 3 (1983), S. 247-259 
    Details
    ISSN: 0886-1544
    Keywords: spermatozoa ; Ciona ; axoneme ; quiescence ; twist ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: A simple planar model of sliding can predict the amount of sliding required to form a certain degree of bend. The accuracy of this prediction relies on the assumptions that no twists occur in the axoneme and that no sliding occurs at the base. However, previous studies indicated that twists may occur.This paper explores a new method for quantitating and analyzing twists. Preliminary results using this method showed that there were twists. In order to control for possible artifacts due to fixation and other preparative procedures, the characteristic S-shaped quiescent state of Ciona spermatozoa was studied.Analyses of platinum replicas of those flagella in which this waveform is well preserved suggest that most, if not all, of the twists observed are due to the artifact of a curved shape settling onto a surface. Detailed analyses indicate that if twists do occur in quiescent sperm, they are probably less than 0.4 radian. Since axonemes are evidently easily twisted in rigor, and even after fixation, caution should be exercised in interpretation of axonemal twists.
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    Masthead (1983)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 3 (1983) 
    Details
    ISSN: 0886-1544
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
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    Crawling caenorhabditis elegans spermatozoa contact the substrate only by their pseudopods and contain 2-nm filaments (1983)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 3 (1983), S. 333-347 
    Details
    ISSN: 0886-1544
    Keywords: Caenorhabditis elegans spermatozoa ; cell motility ; electron microscopy ; cell-substrate contact ; 2-nm filaments ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The locomotion of C. elegans spermatozoa resembles, in many respects, the crawling movements of other eukaryotic cells. However, these sperm contain surprising little actin, which plays no apparent role in this cell's motility. Electron microscopy has revealed that crawling spermatozoa retain a strict morphological polarity so that the organelle-filled cell body is separated from the pseudopod by an array of cytoplasmic laminar membranes. When sperm crawl only the pseudopod contacts the substrate; the cell body is either pulled behind or carried on top of the rear portion of the pseudopod. Fingerlike projections which extend forward from the leading edge of the pseudopod initiate contact with the substrate. The underside of the pseudopod exhibits areas of close (40 nm separation) membrane-substrate association with intervening areas of wide (up to 300 nm) membrane-substrate gaps. The pseudopod cytoplasm contains 2-nm filaments but no filamentous actin has been observed. These 2-nm filaments were detected in thin sections of crawling cells and in negative-stained remnants of spermatozoa disrupted by either hypotonic buffer on Triton X-100. The filaments are found both free in the cytoplasm and closely associated with the cytoplasmic face of the plasma membrane and are usually oriented along the long axis of the cell. Neither the identity nor the function of these filaments has been established although their location and orientation suggest that they may be involved in generating propulsion.
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    F-actin aggregates may activate transformed cell surfaces (1983)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 3 (1983), S. 383-390 
    Details
    ISSN: 0886-1544
    Keywords: F-actin aggregates ; actin-membrane interactions ; transformed/normal cell coculture ; F-actin/tropomyosin interaction ; temperature-sensitive viral mutant ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Observations on the role of transformation-specific F-aggregates [Carley et al, 1981] in altering morphology, adhesion and intercellular interaction in transformed cells are reported here. The appearance and disappearance of membrane- and substrate-associated F-actin aggregates (MAG and SAG, respectively) are followed in a cell line temperature-sensitive for transformation. Since MAG structures also appear near the membrane in suspension cultures of transformed cells and in transformed cells in coculture with untransformed cells, they appear to function at cell-cell contacts. Unlike microfilament bundles in untransformed cells, MAG and SAG do not contain the F-actin regulatory protein tropomyosin. The lack of tropomyosin in these structures near the membrane is reminiscent of areas of an exceptionally active actin cytoskeleton usually associated with motile processes of the normal cell membrane. Such areas of membrane-cytoskeletal interaction may be involved in the aberrant cell-cell communication as well as the aggressive behavior often seen in transformed cells.
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    A 200-kd protein isolated from the fascia adherens membrane domains of chicken cardiac muscle cells is detected immunologically in fibroblast focal adhesions (1983)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 3 (1983), S. 419-429 
    Details
    ISSN: 0886-1544
    Keywords: microfilament-membrane attachments ; cell-cell contacts ; fascia adherens ; immunofluorescence microscopy ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: On the premise that the fascia adherens of cardiac muscle cell intercalated disk membranes is a structure that is closely homologous to the focal adhesions formed by fibroblasts, a fascia adherens preparation was isolated from chicken cardiac muscle, and was analyzed for its protein composition. A prominent 200-kilodalton (kd) protein was purified from the fascia preparation and shown to be antigenically unrelated to several previously characterized cytoskeletal proteins, including cardiac myosin and vinculin. With monospecific antibodies to the 200-kd protein, an identical or closely similar intracellular protein was shown to be associated with the focal adhesion plaques of fibroblasts.
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    Gamma actin, spectrin, and intermediate filament proteins colocalize with vinculin at costameres, myofibril-to-sarcolemma attachment sites (1983)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 3 (1983), S. 449-462 
    Details
    ISSN: 0886-1544
    Keywords: myofibril to sarcolemma attachment ; costamere ; spectrin ; actin ; intermediate filaments ; vinculin ; fibronectin ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Localization of vinculin at the sarcolemma of striated muscle fibers defines an orthogonal lattice. The costameres of the lattice are the riblike bands of vinculin that run perpendicular to the long axis of the fiber, repeat in register with I bands of the subjacent myofibrils, and seem to couple the myofibril to the sarcolemma [Pardo et al 1982, 1983a]. The colocalization studies presented in this paper show that gamma actin, spectrin, and intermediate filament antigens are additional components of this lattice of costameres. In addition, the results show that gamma actin and spectrin are also components of the internal network of collars, first visualized with antibody to desmin [Granger and Lazarides, 1978], that connects the myofibrils to each other at the level of the Z line.
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    Movement of myosin-coated structures on actin cables (1983)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 3 (1983), S. 485-489 
    Details
    ISSN: 0886-1544
    Keywords: cell motility ; myosin ; actin ; vesicle transport ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Myosin-coated spheres from 0.6 to 120 μm in diameter move in vitro on a substratum of polar arrays of actin cables derived from the alga Nitella. The force for this movement is provided by skeletal muscle myosin since it is ATP-dependent, and N-ethylmaleimide (NEM) inactivation of the myosin blocks movement. These observations demonstrate that attachment of myosin in a random orientation to structures will enable those structures to move along polar arrays of actin filaments.
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    Actin-mediated surface motility during sea urchin fertilization (1983)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 3 (1983), S. 513-524 
    Details
    ISSN: 0886-1544
    Keywords: fertilization ; actin ; microfilaments ; sea urchin ; cell division ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The sea urchin egg at fertilization is an ideal model in which to study actin-mediated surface activity. Electron microscopy of unfertilized eggs demonstrates the presence of thousands of well-arrayed short microvilli, which appear supported by cytochalasin-sensitive actin oligomers as detected with rhodamine-labeled phalloidin staining of permeabilized eggs. At insemination, the previously short microvilli elongate and cluster around the successful sperm during incorporation. Phalloidin staining demonstrates a tremendous recruitement of polymerized actin into the site of sperm incorporation, resulting in the formation of the fertilization cone. Fertilization of cytochalasin-treated eggs results in the normal activation of the metabolic and bioeletric events, but sperm incorporation does not occur since the localized actin assembly required for fertilization cone formation is precluded. After sperm incorporation, the entire fertilized surface is restructured, as a result of a massive polymerization of actin to produce a burst in microvillar elongation. Addition of cytochalasin to eggs immediately following sperm incorporation demonstrates the recruitment of actin assembly for the proper progression through the first cell cycle. During normal cell divison, the egg surface retains the long microvilli. The furrow which forms at cytokinesis does not appear as a unique new structure, but rather as a reorganization of the cortical microfilaments. Quantitative fluorescence microscopy argues against an increase in microfilaments during early cytokinesis. At the latest stages of cytokinesis, a thickening of the cortical actin is noted, which could possibly be interpreted as a contractile ring. A minor basal level of actin assembly with numerous nucleation sites in unfertilized eggs and a tremendous but localized assembly of microfilaments surrounding the sperm during incorporation, followed by a massive global microfilament assembly event to elongate the fertilized egg microvilli resulting later in the reorganization of these microfilaments to produce the forces necessary for cytokinesis, highlight the utility of the study of sea urchin eggs at fertilization for understanding actin-membrane interactions.
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    Identification of fibrinogen derivatives in the triton-insoluble residue of human blood platelets (1983)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 3 (1983), S. 21-30 
    Details
    ISSN: 0886-1544
    Keywords: platelets ; Triton-insoluble residue ; fibrinogen ; fibrin ; tubulin ; cytoskeleton ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Several proteins (eg, actin, myosin, and actin-binding protein) in the Tritoninsoluble residue of thrombin-stimulated platelets are important in the formation of cytoskeletal structures. Electrophoretic analyses have shown that unidentified protein bands of 68,000, 55,000, and 48-50,000 daltons are also present in larger amounts after thrombin stimulation. Since these molecular weights correspond roughly to those of the α, β, and γ chains of fibrin, and since fibrinogen is found in platelet α-granules, these bands were compared to those obtained when purified fibrinogen was treated with thrombin, exposed to 1% Triton X-100-5 mM EGTA, and the resultant Triton-insoluble residue sedimented. Identification of the 68,000-, 55,000-, and 48--50,000-dalton bands as fibrinogen derivatives was confirmed by identifying them in comigration studies and in autoradiographs of Triton-insoluble residues of platelets that were electrophoretically transferred to nitrocellulose paper and treated with antifibrinogen antibody and 125I-protein A. Furthermore, if the platelet suspension was treated with thrombin in the presence of calcium ions, protein bands characteristic of the action of Factor XIII on fibrin were observed, active platelet Factor XIII apparently having been made available by lysis of platelets during preparation. Making use of the electrophoretic properties of tubulin recently described by Best et al [1981], comigration studies using hog brain tubulin indicated that tubulin is not present in significant amounts in the Triton-insoluble residue of platelets as previously suggested. The identification of these proteins as fibrinogen derivatives does not demonstrate a physiological interaction between fibrin and the platelet cytoskeleton, since fibrin is Tritoninsoluble and can be pelleted even in the absence of platelet cytoskeletons.
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    Erratum (1983)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 3 (1983), S. 109-109 
    Details
    ISSN: 0886-1544
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cm.970030109
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    Changes in cytoskeletal proteins of polymorphonuclear leukocytes induced by chemotactic peptides (1983)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 3 (1983), S. 349-361 
    Details
    ISSN: 0886-1544
    Keywords: myosin phosphorylation ; actin polymerization ; chemotactic factors ; leukocytes ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Changes in the state of polymerization of actin and phosphorylation of myosin have been observed in polymorphonuclear leukocytes (PMNs) soon after the addition of the chemotactic peptide N-formylnorleucylleucylphenylalanine. At a time when the cells are observed to extend many ruffles or lamellipodia from their surface, the fraction of the cellular actin present in a monomeric form is decreased by about 25% as assayed by the ability of the G-actin to inhibit DNAase. These changes are temporally correlated with an increase in the staining by nitrobenzooxadiazole (NBD)-phallacidin, a probe that binds F-actin selectively. The NBD-phallacidin staining is observed in the surface ruffles. When the peptide concentration is decreased by addition of a tenfold excess of buffer, cells withdraw their surface ruffles and form blebs. These changes correlate with an increase in the G-actin levels detected with the DNAase inhibition assay. An increase in phosphorylation of the 20,000-dalton light chain of myosin is also observed in leukocytes stimulated by addition of chemotactic peptide. These observations of changes in cytoskeletal proteins of PMNs provide a beginning for further studies on the regulation of cell motility by chemotactic factors.
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    Complexes containing actin and spectrin from erythrocyte and brain (1983)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 3 (1983), S. 375-382 
    Details
    ISSN: 0886-1544
    Keywords: actin ; spectrin ; band 4.1 ; cytochalasins ; erythrocyte ; brain ; actin-membrane attachment ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: A complex of proteins with properties similar to those of erythrocyte spectrinband 4.1-actin complex has been idientified in a preparation derived from bovine brain. The complex has an apparent sedimentation coefficient of about 26S, and contains brain spectrin (also called fodrin) and actin as major components. The actin in the complex is in the oligomeric form, which nucleates assembly of actin filaments that grow from the “barbed” end. The complex cross-links actin filaments, resulting in an increase in low-shear viscosity. Whether the complex contains a protein analogous to erythrocyte band 4.1 is not known. However, it can be demonstrated that brain spectrin has the capability to interact with band 4.1 in a way which increases its ability to cross-link actin filaments.
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    Darstellung und Eigenschaften von und Reaktionen mit metallhaltigen Heterocyclen, XXIV. P- und S-isomere Heteronickelacyclopentadiene als Abfangprodukte der instabilen dreigliedrigen Ringsysteme (h5-C5H5) mit aktivierten Alkinen (1983)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 116 (1983), S. 46-54 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Preparation and Properties of, and Reactions with, Metal-Containing Heterocycles, XXIV. P- and S-isomeric Heteronickelacyclopentadienes as Trapping Products of the Unstable Three-membered Ring Systemswith Activated AlkynesThe unstable three-membered ring systems (2a, b) (L = h5-C5H5), which dimerize immediately at room temperature to give [LNiS=PR21]2 (3a, b), are obtained by reaction of L2Ni with diorganylphosphane sulfides R21HPS (1a, b). Between 2a, b and 3a, b there exists a dissociative equilibrium. 2a, b, however, are trapped with activated alkynes of the type R2C ≡ CR2 with formation of the S- and P-isomeric heteronickelacyclopentadienes (4aS - dS) and (4bP - dP) which can be differentiated by their colour and for R1=CH3 also with respect to the 1H NMR spectra. According to an X-ray structural analysis, 4aS crystallizes in the monoclinic space group P21/n with Z = 4.
    Notes: Bei der Umsetzung von L2Ni (L = h5-C5H5) mit den Diorganylphosphansulfiden R21HPS (1a, b) erhält man die instabilen, dreigliedrigen Ringsysteme (2a, b), die bei Raumtemperatur sofort zu [LNiS=PR21]2 (3a, b) dimerisieren. Zwischen 2a, b und 3a, b liegt ein dissoziatives Gleichgewicht vor. 2a, b lassen sich jedoch mit aktivierten Alkinen R2C ≡ CR2 unter Bildung der S- und P-isomeren Heteronickelacyclopentadiene (4aS - dS) und (4bP - dP) abfangen, welche sich in ihrer Farbe und für R1=CH3 auch in den 1H-NMR-Spektren unterscheiden. Nach einer Röntgenstrukturanalyse kristallisiert 4aS in der monoklinen Raumgruppe P21/n mit Z = 4.
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    Cycloadditionsreaktionen von Heterocumulenen, XXVI. Cycloaddukte aus Arylisothiocyanaten und 2,2-disubstituierten Enaminen (1983)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 116 (1983), S. 55-65 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Cycloaddition Reactions of Heterocumulenes, XXVI. Cycloadducts from Aryl Isothiocyanates and 2,2-Disubstituted EnaminesAryl isothiocyanates 1 react with enamines 2 to give two types of 2:1 cycloadducts. Below 50°C, 1a - g and 2 give rise to 6-imino-1,3-thiazine-2-thiones 5, the constitutions of which are proved by an X-ray analysis of 5c. Above 50°C or starting from 4-nitrophenyl isothiocyanate (1h),2,4-dithiouracils 6 are formed. 1:1 cycloadducts of the reactants are detected spectroscopically; on workup, they hydrolyze to give 2-formylthiopropionanilides 9.
    Notes: Arylisothiocyanate 1 und Enamine 2 reagieren zu zwei Typen von 2:1-Cycloaddukten. Unterhalb von 50°C entstehen aus 1a - g und 2 6-Imino-1,3-thiazin-2-thione 5, deren Konstitution durch die Röntgenstrukturanalyse von 5c bewiesen wurde. Oberhalb 50°C oder aus 4-Nitrophenylisothio-cyanat (1h) bilden sich 2,4-Dithiouracile 6. 1:1-Cycloaddukte der Reaktanten lassen sich spektroskopisch nachweisen; bei der Aufarbeitung hydrolysieren sie zu 2-Formylthiopropionaniliden 9.
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    Cycloadditionsreaktionen von Heterocumulenen, XXVII. 2-Alkyliden-1,3,4-thiadiazoline durch 1,3-dipolare Cycloaddition von Diazoalkanen an Thioketene (1983)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 116 (1983), S. 66-73 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Cycloaddition Reactions of Heterocumulenes, XXVI. 2-Alkylidene-1,3,4-thiadiazolines via 1,3-Dipolar Cycloaddition of Diazoalkanes to ThioketenesBased on 13C NMR data, the constitution of 2-alkylidene-1,3,4-thiadiazolines 3 is assigned to the 1 : 1 cycloadducts from thioketenes 1 and diazoalkanes 2a, b. The alkynyl silyl sulfide 15 also forms this heterocyclic system with 2a. However, the allyl(silyl)thioketene 12 reacts with 2a to give a 3 H-pyrazole 13b, which is derived from the addition to the C ≡ C bond of the valence tautomeric allyl silylethynyl sulfide 11.
    Notes: Aufgrund von 13C-NMR-Daten wird den 1 : 1-Cycloaddukten aus Thioketenen 1 und den Diazoalkanen 2a, b die 2-Alkyliden-1,3,4-thiadiazolin-Konstitution 3 zugeordnet. Auch das Alkinyl(silyl)sulfid 15 bildet mit 2a diesen Heterocyclen-Typ. Das Allyl(silyl)thioketen 12 reagiert mit 2a dagegen zu einem 3H-Pyrazol 13b, das sich von der Addition an die C ≡ C-Bindung des valenztautomeren Allyl(silylethinyl)sulfids 11 ableitet.
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    Über Metallalkyl- und -aryl-Verbindungen, XXIX. Darstellung und Kristallstruktur von Methylnatrium mit variablen Methyllithium-Gehalten, Verbindungen mit (CH3Na)4- und (CH3Li)4-Einheiten (1983)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 116 (1983), S. 74-85 
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    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Metal Alkyl and Aryl Compounds, XXIX. Preparation and Crystal Structure of Methylsodium with Variable Methyllithium Content, Compounds with (CH3Na)4 and (CH3Li4) UnitsMethylsodium has been prepared by the reaction of methyllithium with sodium tert-butoxide. Depending upon the reaction conditions the preparations contain variable amounts of methyllithium (Na : Li atomic ratio ca. 36:1 to 3:1). Their crystal structures could be determined from powder diagrams. All preparations have a cubic unit cell (a = 2020 pm, space group F 43c) with 24 (CH3Na)4 units. Their geometry is analogous to that of (CH3Li)4 with distances Na—Na 312, 318, Na—C 258, 264, and Na—C 276 pm between adjacent tetramers. Due to their mutual arrangement 8 large cavities are formed which can incorporate (CH3Li)4 units up to a maximum ratio of (CH3Na)4: (CH3Li)4 = 3:1. - The bonding within the (CH3Na)4 groups resembles largely to that of (CH3Li)4 with more strongly polarized Na3C four-center bonds. The IR spectra of (CH3Na)4 and (CH3Li)4 are discussed.
    Notes: Methylnatrium wurde durch Umsetzung von Methyllithium mit Natrium-tert-butoxid erhalten. Je nach den Reaktionsbedingungen enthalten die Präparate variable Mengen an Methyllithium (Na:Li-Atomverhältnis ca. 36:1 bis 3:1). Ihre Kristallstrukturen konnten aus Pulverdiagrammen ermittelt werden. Alle Präparate haben eine kubische Elementarzelle (a = 2020 pm, Raumgruppe F 43 c) mit 24 (CH3Na)4-Einheiten. Ihre Geometrie ist analog der von (CH3Li)4 mit den Abständen Na—Na 312, 318, Na—C 258, 264 und Na—C 276 pm zwischen benachbarten Tetrameren. Infolge ihrer speziellen gegenseitigen Anordnung entstehen 8 große Hohlräume, welche (CH3Li)4 -Einheiten bis zu einem maximalen Verhältnis (CH3Na)4:(CH3Li)4 = 3:1 einschließen können. - Die Bindung in den (CH3Na)4-Gruppen entspricht noch weitgehend der von (CH3Li)4 mit stärker polarisierten Na3C-Vierzentrenbindungen. Die IR-Spektren von (CH3Na)4 und (CH3Li)4 werden diskutiert.
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    Anwendung von Kraftfeldrechungen, IV. Ein Kraftfeld für die Berechnung von Struktur und Bildungsenthalpie von Alkylbenzolen und sein Verläßlichkeitstest an hochgespannten Diphenylethanen (1983)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 116 (1983), S. 86-96 
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    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Application of Force Field Calculations, IV. A Force Field for the Calculation of the Structures and Heats of Formation of Alkylbenzenes and its Test of Reliability on Highly Strained DiphenylethanesAllinger's force field MM26) was expanded to the calculation of the molecular structures and heats of formation of alkylated benzenes by additional parameters. Calculations on highly congested diphenylethanes were performed. These compounds are distinguished by long C—C-bonds, by large bond angle deformations and by high strain enthalpies (up to 45 kcal · mol-1). The excellent agreement between calculational results and experimentally determined data proves high reliability of the extended force field. - Furthermore strain-free increments for phenyl groups are given to put the strain enthalpies of phenyl and alkyl groups on the same scale.
    Notes: Zur Berechnung von Struktur und Bildungsenthalpie von Alkylbenzolen wurde das Kraftfeld MM2 von Allinger6) mit Parametern ergänzt. Testrechnungen wurden durchgeführt an hochverzweigten Diphenylethanen, die sich auszeichnen durch stark gedehnte C—C-Bindungen, aufgeweitete Bindungswinkel und hohe Spannungsenthalpien (bis zu 45 kcal · mol-1). Die ausgezeichnete Übereinstimmung der Rechenergebnisse mit experimentellen Daten belegt die hohe Verläßlichkeit des erweiterten Kraftfeldes. - Außerdem wurden spannungsfreie Inkremente für Phenylgruppen angegeben, um die Spannungsenthalpie einheitlich für Alkyl- und Phenylgruppen angeben zu können.
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    Übergangsmetall-Schwefelylid-Komplexe, XIV. π-Komplexe von 1-Alkyl-3,5-diphenyl-λ4-thiabenzolen mit Dicarbonylnitrosylchrom (1983)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 116 (1983), S. 197-206 
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    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Transition Metal Sulfur Ylide Complexes, XIV. π-Complexes of 1-Alkyl-3,5-diphenyl-λ4-thiabenzenes with Dicarbonylnitrosylchromium1-Alkyl-3,5-diphenyl-λ4-thiabenzene chromium complexes 2a-f are oxidized by NOPF6 in CH2Cl2 at -70°C, yielding the cationic dicarbonylnitrosyl complexes 3a-f. The temperature dependence of the 1H NMR spectra of 3a-f is consistent with a hindered rotation of the ring ligands. The X-ray structure analysis of 3b shows that the molecule in the solid state possesses no local Cs-symmetry.
    Notes: Die 1-Alkyl-3,5-diphenyl-λ4-thiabenzol-Chromkomplexe 2a-f werden durch NOPF6 in CH2Cl2 bei -70°C unter Bildung der kationischen Dicarbonylnitrosyl-Spezies 3a-f oxidiert. Die temperaturabhängigen 1H-NMR-Spektren dieser Komplexe deuten auf gehinderte Rotation der Ringe um das (CO)2(NO)Cr+-Fragment hin. Die Röntgenstrukturanalyse von 3b zeigt, daß das Molekül im Kristall keine lokale Cs-Symmetrie mehr besitzt.
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    URL: http://dx.doi.org/10.1002/cber.19831160122
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    Stereologe Kronenether: π-Donorbeteiligung bei der Komplexierung von Kationen? (1983)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 116 (1983), S. 215-219 
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    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Stereologous Crown Ethers: π-Donor Participation in the Complexation of Cations?In the framework of the “stereology concept” the new crown ethers 8, 9, and for comparison 11 have been synthesized and their stability constants with Ag+ ions determined by 1H NMR spectroscopy. The results may be interpreted as evidence for a π-participation of aromatic nuclei of the ligands in the complexation of certain cations.
    Notes: Im Rahmen des „Stereologie-Konzepts“ wurden die neuartigen Kronenether 8, 9 und zum Vergleich 11 synthetisiert und deren Komplexkonstanten gegenüber Ag+-Ionen 1H-NMR-spektroskopisch ermittelt. Die Befunde machen eine π-Donorbeteiligung aromatischer Kerne bei der Komplexierung bestimmter Kationen wahrscheinlich.
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    Neue helicale Kohlenwasserstoffe, VIII. Enantiomerentrennung, Circulardichroismus, Racemisierung und Röntgenstrukturanalyse des Benzo[2.2]metacyclophans (1983)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 116 (1983), S. 207-214 
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    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: New Helical Hydrocarbons, VIII. Enantiomer Separation, Circular Dichroism, Racemization, and X-Ray Analysis of Benzo[2.2]-metacyclophaneThe title compound 1 was separated into the enantiomers by chromatography on cellulose triacetate: (-)-1 exhibits an enantiomeric purity of 100% with [α]36520 = -3210 ± 135 (acetone). A racemization barrier ΔG≠ = 125 kJ/mol is found by means of a kinetic study. The helicity of the molecule is demonstrated through these results as well as through an X-ray analysis, which is also described.
    Notes: Die Titelverbindung 1 wird chromatographisch an Cellulosetriacetat in die Enantiomeren getrennt: (-)-1 hat mit 100% Enantiomerenreinheit einen Drehwert von [α]36520 = -3210 ± 135 (Aceton). Für die Racemisierung wird kinetisch eine Barriere ΔG≠ = 125 kJ/mol ermittelt. Der helicale Molekülbau ist hiermit und durch die Röntgenstrukturanalyse gesichert, die gleichfalls beschrieben wird.
    Additional Material: 6 Tab.
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    URL: http://dx.doi.org/10.1002/cber.19831160123
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    Isomerisierung von 2-Alkoxycyclopropancarbonsäuren - Eine effektive Synthese von 4-Oxocarbonsäuren (1983)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 116 (1983), S. 220-229 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Isomerisation of 2-Alkoxycyclopropanecarboxylic Acids - An Effective Synthesis of 4-Oxo Carboxylic Acids(Z/E)-2-2-Alkoxycyclopropanecarboxylic esters 2/3 were prepared from enol ethers 1 and ethyl diazoacetate. The saponification of these esters gives the corresponding (Z/E)-2-alkoxycyclopropanecarboxylic acids 4/5, which show stereomutation in water/methanol. This isomerisation was studied in labelled solvents and interpreted for the example of (E)-2-methoxy-2-phenylcyclopropanecarboxylic acid (5a). On heating in water/methanol the compounds 4/5 are transformed quantitatively into the corresponding 4-oxo carboxylic acids 6.
    Notes: (Z/E)-2-Alkoxycyclopropansäureester 2/3 werden aus Enolethern 1 und Diazoessigester hergestellt. Durch Verseifen entstehen die (Z/E)-2-Alkoxycyclopropancarbonsäuren 4/5, welche in Wasser/Methanol Stereomutation zeigen. Diese Isomerisierung wird an (E)-2-Methoxy-2-phenyl-cyclopropancarbonsäure (5a) in deuterierten Lösungsmitteln untersucht und mechanistisch interpretiert. Beim Erwärmen in Wasser/Methanol öffnen sich die Verbindungen 4/5 quantitativ zu den entsprechenden 4-Oxocarbonsäuren 6.
    Additional Material: 3 Tab.
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    (Cycloalkeno-1,2,3-selenadiazol- und -thiadiazol)carbonyl-(6B)-metall-Komplexe (1983)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 116 (1983), S. 230-237 
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    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Cycloalkeno-1,2,3-selenadiazole and -thiadiazole Carbonyl Complexes of Chromium, Molybdenum, and TungstenThe reactions of cycloalkeno-1,2,3-selenadiazoles 1 and -thiadiazoles 2 with pentacarbonyl-(6B)-metal(THF) complexes afford stable compounds M(CO)5(selenadiazole) (3-5) and M(CO)5(thiadiazole) (6) with the heteroaromatic ligand coordinating via its nitrogen atom in the 2-position. Reactions of cyclohexa-1,2,3-selenadiazole 1b with Mo(CO)4(norbornadiene) and with Mo(CO)3(CH3CN)3 produce a Mo(CO)4(selenadiazole)2 complex with the two terminal selenadiazole ligands in the cis-position, and a complex [Mo(CO)3]2(selenadiazole)3 with three bridging ligands, respectively. The reaction of Fe2(CO)9 with W(CO)5(selenadiazole), as compared with the free ligand, leads to a small variation of the formed products which might be explained with the intermediate formation of a labile dinitrogen pentacarbonyltungsten complex.
    Notes: Cycloalkeno-1,2,3-selenadiazole 1 und -thiadiazole 2 reagieren mit Pentacarbonyl-(6B)-metall-(THF) zu stabilen Komplexen der Zusammensetzung M(CO)5 (Selenadiazol) (3-5) und M(CO)5(Thiadiazol) (6), wobei die heteroaromatischen Liganden jeweils über N(2) komplexiert sind. Die Reaktionen von Cyclohexa-1,2,3-selenadiazol 1b mit Mo(CO)4(Norbornadien) und mit Mo(CO)3(CH3CN)3 führen zu cis-Mo(CO)4(Selenadiazol)2 mit zwei terminalen und zu [Mo(CO)3]2(Selenadiazol)3 mit drei verbrückenden Selenadiazol-Liganden. Bei der Umsetzung von W(CO)5(Selenadiazol) mit Nonacarbonyldieisen wird ein, verglichen mit der analogen Reaktion des freien Liganden, veränderter Reaktionsverlauf beobachtet, was mit der Bildung einer labilen Stickstoff-pentacarbonylwolfram-Zwischenstufe erklärt werden könnte.
    Additional Material: 3 Tab.
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    URL: http://dx.doi.org/10.1002/cber.19831160126
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  • 78
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    Synthese und Umlagerung substituierter Bicyclo[2.1.0]pent-2-ene. Eine thermische „walk“-Umlagerung (1983)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 116 (1983), S. 299-322 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Synthesis and Rearrangement of Substituted Bicyclo[2.1.0]pent-2-enes. A Thermal “Walk”-RearrangementThe synthesis and the thermal behaviour of methyl 5-methyl-, 1,5-, and 2,5-dimethylbicyclo-[2.1.0]pent-2-ene-5-carboxylates 3a, b, 4a, b, 5a, b, as well as of 1,5- and 2,5-dimethylbicyclo-[2.1.0]pent-2-ene-5-carbonitriles 6a, 7a, b are reported. The “walk”-rearrangement which is degenerate in the cases of 3a, b could be detected experimentally with the aid of the dimethyl derivatives 4a, b, 5a, b, 6a, and 7a, b. Electrocyclic ring opening to the correspondingly substituted 1,3-cyclopentadienes competes with the “walk”-rearrangements. Already at 0°C the “walk”-rearrangements 4a → 5a, 4b → 5b, and 6a → 7a proceed stereospecifically with inversion at the migrating carbon atom C-5 as postulated by Woodward and Hoffmann (0°C: ΔG* = 21.7, 24.8, and 21.9 kcal/mol). We assume that the surprisingly low activation barriers do not only result from the resonance stabilization of an aromatic transition state but largely from the anomalously high ground-state enthalpy of the bicyclopentene system.
    Notes: Synthese und thermisches Verhalten der 5-Methyl-, 1,5-Dimethyl- und 2,5-Dimethylbicyclo-[2.1.0]pent-2-en-5-carbonsäure-methylester 3a, b, 4a, b, 5a, b und -carbonitrile 6a, 7a, b werden beschrieben. Die in den Systemen 3a, b strukturell entartete „walk“-Umlagerung konnte am Beispiel der Dimethylderivate 4a, b, 5a, b, 6a und 7a, b experimentell nachgewiesen werden. Dazu konkurrierend finden elektrocyclische Ringöffnungen zu den entsprechend substituierten 1,3-Cyclopentadienen statt. Die „walk“-Umlagerungen 4a → 5a, 4b → 5b und 6a → 7a erfolgen bereits bei 0°C stereospezifisch mit der von Woodward und Hoffmann postulierten Inversion am wandernden Kohlenstoff C-5 (0°C: ΔG* = 21.7, 24.8 bzw. 21.9 kcal/mol). Vermutlich resultieren die überraschend niedrigen Aktivierungsbarrieren nicht allein aus der Resonanzstabilisierung eines aromatischen Übergangszustandes, sondern wesentlich aus der anomal hohen Grundzustandsenthalpie des Bicyclopentensystems.
    Additional Material: 7 Tab.
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    URL: http://dx.doi.org/10.1002/cber.19831160134
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    Pseudo-einstufige C—C-Spaltungen beim Zerfall von ionisierten Carbonsäuren. Radikaltypische Reaktionen in der Massenspektrometrie (1983)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 116 (1983), S. 323-347 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Pseudo One-Step Cleavage of C—C Bonds in the Decomposition of Ionized Carboxylic Acids. Radical Like Reactions in Mass SpectrometryMetastable molecular ions of hexanoic acid (1) decompose unimolecularly to C2H5· and protonated methacrylic acid (5-Hℸ +) (92% rel. abund.). Investigation of the mechanism reveals that 1) the branched cation radical 11 must be regarded as the essential intermediate in the course of the rearrangement/dissociation reaction and 2) the process commences with intramolecular hydrogen transfer from either C-3 or C-5 to the ionized carbonyl oxygen („hidden“ hydrogen migration). Hydrogen transfer from C-4, which would correspond to the well-known McLafferty rearrangement, is of no importance in the C2H•5-elimination from 1. The same conclusion applies for various alternative mechanisms, as for example a SRi type reaction, 1 → 2-Hℸ +. The gas phase chemistry of the cation radical of 1, and in particular the hydrogen exchange processes between the methylene groups C-2/C-3 and C-5/C-6, is in surprisingly close correspondence to the chemistry of free alkyl radicals. - The syntheses of various 13C and 2H-labelled model compounds are described.
    Notes: Metastabile Molekül-Ionen von Hexansäure (1) zerfallen unimolekular zu C2H5· und protonierter Methacrylsäure (5-Hℸ +) (92% rel. Intensität). Untersuchungen zum Mechanismus der Reaktion enthüllen, daß 1. das verzweigte Radikalkation 11 als entscheidende Zwischenstufe im Umlagerungs-/Eliminierungsprozeß fungiert und 2. die Reaktion durch einen intramolekularen Wasserstofftransfer von sowohl C-3 als auch C-5 auf die ionisierte Carboxylgruppe eingeleitet wird („verborgene“ H-Wanderung). Wasserstoffübertragungen von C-4, analog zum bekannten McLafferty-Typus, spielen beim Zerfall von 1 keine Rolle. Dies gilt auch für diverse mechanistische Varianten, wie z. B. eine SRi-Reaktion 1 → 2-Hℸ +, die ebenfalls ohne Bedeutung sind. Die Gasphasenchemie des Radikalkations von 1 - und hier vor allem die Wasserstoff-Austauschprozesse zwischen den Methylengruppen C-2/C-3 und C-5/C-6 - zeigt eine überraschende Verwandtschaft zur Chemie freier Alkylradikale. - Die Synthesen 13C- und 2H-markierter Modellverbindungen werden beschrieben.
    Additional Material: 8 Tab.
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    URL: http://dx.doi.org/10.1002/cber.19831160135
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    Nachweis von 4-Homocubyl-Carbenium-Ionen als reaktive Zwischenstufen (1983)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 116 (1983), S. 360-366 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Evidence for 4-Homocubyl Carbenium Ions as Reactive Intermediates4-(Hexafluoroisopropoxy)homocubane (6) is the main product of the thermolysis reaction of N-(4-homocubyl)-N-nitrosoacetamide (9) and of the solvolysis reaction of 4-homocubyl bromide (5) in hexafluoro-2-propanol. This is experimental evidence for 4-homocubyl carbenium ions as intermediates in both reactions. The solvolysis rate of 4-homocubyl bromide at 120°C in the same solvent (k1120°C=1.3 · 10-7s-1) by far exceeds that of 1-norbornyl bromide which does not react at a detectable rate under these conditions. According to force field calculations the strain enthalpy is increasing by as much as 66 kcal · mol-1 in the ionisation of 4-homocubyl bromide. Therefore nonclassical stabilization of the 4-homocubyl carbenium ion is postulated.
    Notes: Bei der Thermolyse von N-(4-Homocubyl)-N-nitrosoacetamid (9) und bei der Solvolyse von 4-Homocubylbromid (5) in Hexafluor-2-propanol entsteht 4-(Hexafluorisopropoxy)homocuban (6) als Hauptprodukt. Dies beweist das Auftrete von 4-Homocubyl-Carbenium-Ionen als Zwischenstufen beider Reaktionen. Die Solvolysegeschwindigkeit von 4-Homocubylbromid bei 120°C in Hexafluor-2-propanol (k1120°C = 1.3 · 10-7 s-1) ist wesentlich höher als die von 1-Norbornylbromid, dessen Solvolyse unter diesen Bedingungen nicht nachweisbar ist. Da die Ionisation von 4-Homocubylbromid nach Kraftfeldrechnungen mit 66 kcal · mol-1 Ansteigen an Spannungsenthalpie verbunden ist, wird für das 4-Homocubyl-Carbenium-Ion eine nichtklassische Stabilisierung angenommen.
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    URL: http://dx.doi.org/10.1002/cber.19831160137
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    Übergangsmetall-substituierte Phosphane, Arsane und Stibane, XXXIII. (Brommethyl)bis[(trimethylsilyl)methyl]arsan: Darstellung und Metallierung zu Komplexen mit η1 - oder η2-koordiniertem Arsinomethyl-Liganden (1983)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 116 (1983), S. 348-359 
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    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Transition Metal Substituted Phosphanes, Arsanes, and Stibanes, XXXIII. (Bromomethyl)bis[(trimethylsilyl)methyllarsane: Synthesis and Metalation to Complexes with η1- or η2-Coordinated Arsinomethyl LigandThe pyrolysis of the trialkyldibromoarsorane (Me3SiCH2)3AsBr2 (1) under reduced pressure yields the (bromomethyl)arsane (Me3SiCH2)2AsCH2Br (2) with Me3SiBr elimination via the intermediate formation of the bromodialkylmethylenearsorane Br(Me3SiCH2)2As=CH2. 2 reacts with Na[M(CO)3Cp] (M=Mo, W) to give the transition metal substituted arsanes Cp(CO)3M-CH2As(CH2SiMe3SiMe3)2 (3a,b). These undergo cyclisation with loss of CO and formation of Cp(CO)2M[η2 CH2As(CH2SiMe3)2] (4a,b), the first complexes with an η2-bound arsinomethyl unit, either spontaneously (3a) or upon ultraviolet irradiation or prolonged standing at room temperature (3b). MeI quaternizes the arsane 3b to give the metalated arsonium salt [Cp(CO)3W - CH2As(Me)(CH2SiMe3)2]I (5). The NMR spectra indicate fluxional behaviour for the chiral metallacycles 4a, b. It is caused by a rapid change of the configuration at the metal centre, for which a mechanism, involving a rotation of the dihapto-coordinated ligand about an axis defined by the metal and the centre of the As—C(M) bond, is suggested.
    Notes: Die Pyrolyse des Trialkyldibromarsorans (Me3SiCH2)3AsBr2 (1) bei reduziertem Druck liefert unter Me3SiBr-Eliminierung über die intermediäre Stufe eines Bromdialkylmethylenarsorans Br(Me3SiCH2)2)2As=CH2 das (Brommethyl)arsan (Me3SiCH2)2AsCH2Br (2). Dieses reagiert mit Na[M(CO)3Cp] (M=Mo, W) zu den Übergangsmetall-substituierten Arsanen Cp(CO)3M-CH2As(CH2SiMe3)2 (3a,b), welche sich spontan (3a) bzw. bei UV-Bestrahlung oder längerem Stehenlassen bei Raumtemperatur (3b) unter CO-Verlust in Cp(CO)2M[η2-CH2As(CH2SiMe3)2] (4a,b), die ersten Komplexe mit η2-gebundener Arsinomethyl-Einheit, umwandeln. MeI quartärisiert das Arsan 3b zum metallierten Arsoniumsalz [Cp(CO)3W - CH2As(Me)(CH2SiMe3)2]I (5). Die NMR-Spektren zeigen für die chiralen Metallacyclen 4a, b fluktuierendes Verhalten an. Als Mechanismus für den dafür verantwortlichen schnellen Konfigurationswechsel am Zentralmetall wird die Rotation des dihapto-koordinierten Liganden um eine durch das Metall und den Mittelpunkt der As—C(M)-Bindung verlaufende Achse vorgeschlagen.
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    Darstellung und Strukturbestimmung von Ammoniak-Phosphorpentafluorid (1/1) (1983)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 116 (1983), S. 367-374 
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    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Synthesis and X-Ray Structure Analysis of Ammonia-Phosphorus Pentafluoride (1/1)The adduct H3N · PF5 (1) is obtained in 8% yield from the reaction of NH3 with PF5, in 41% yield, however, from HF and (F2PP=N)3. The x-ray structure analysis shows only slightly distorted octahedral geometry at phosphorus with a P—N bond length of 1.842 Å. 14N-H, 14N-P-F(cis), and 14N-P coupling constants are found in the 1H, 19F, and 31P NMR spectra.
    Notes: Das Addukt H3N · PF5 (1) wird in 8proz. Ausbeute bei der Reaktion von H3N mit PF5 und in 41proz. Ausbeute durch Umsetzung von wasserfreiem HF mit (F2P=N)3 erhalten. Die Röntgenstrukturanalyse ergibt eine nur wenig verzerrte oktaedrische Geometrie mit einem P—N-Bindungsabstand von 1.842 Å. Aus den 1H-, 19F- und 31P-NMR-Spektren können die Kopplungen 14N-H, 14N-P-F(cis) und 14N-P entnommen werden.
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    URL: http://dx.doi.org/10.1002/cber.19831160138
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    Anodische Fragmentierung O-acylierter α-Hydroxycarbonsäuren (1983)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 116 (1983), S. 375-388 
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    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Anodic Fragmentation of O-Acylated α-Hydroxy Carboxylic AcidsDepending on the degree of substitution at the α-carbon atom, the electrolyses of O-acylated α-hydroxy carboxylic acids 1 yield products of fragmentation (aldehydes or ketones 5) and products derived from acylium ions 4 in concurrence with simple anodic substitution products (acylales, amides, and imides, respectively). Dioxiranyl cations 2 are involved as intermediates. The fragmentation of the dioxiranyl cation 2 is investigated by semiempirical MINDO/3 calculations (Scheme 1).
    Notes: Die Elektrolyse O-acylierter α-Hydroxycarbonsäuren 1 liefert über Dioxiranyl-Kationen 2 als Zwischenstufen je nach Substitutionsgrad am α-Kohlenstoffatom von 1 Fragmentierungsprodukte (Aldehyde oder Ketone 5) und Folgeprodukte von Acylium-Ionen 4 in Konkurrenz zu einfachen anodischen Substitutionsprodukten (Acylale bzw. Amide und Imide). Die Fragmentierung des Dioxiranyl-Kations 2 (Schema 1) wurde mit semiempirischen Methoden (MINDO/3) untersucht.
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    Monoozonolyse von 2,3-Dimethylbutadien in Pentan und in Methanol (1983)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 116 (1983), S. 409-415 
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    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Monoozonolysis of 2,3-Dimethylbutadiene in Pentane and in Methanol2,3-Dimethylbutadiene (1) was attacked predominantly at only one double bond by a deficient amount of ozone in pentane or in methanol. In pentane, an α,β-unsaturated ozonide (4) was formed, which was further converted into an α,β-dibromoozonide (2) and into an α,β-epoxyozonide (6), respectively. Ozonolysis of 1 in methanol afforded an α,β-unsaturated methoxy hydroperoxide (8) and formaldehyde as well as a joint coproduct (9) of the latter two fragments.
    Notes: 2,3-Dimethylbutadien (1) wurde von einem Unterschuß an Ozon in Pentan oder in Methanol überwiegend nur an einer Doppelbindung angegriffen. In Pentan entstand ein α,β-ungesättigtes Monoozonid (4), aus welchem ein α,β-Dibromozonid (2) und ein α,β-Epoxyozonid (6) hergestellt wurden. Ozonolyse von 1 in Methanol ergab ein α,β-ungesättigtes Methoxyhydroperoxid (8) und Formaldehyd sowie ein gemeinsames Folgeprodukt (9) dieser Fragmente.
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    1,3-Dipolare Cycloadditionen, 89. Neue Beiträge zur Chemie des Diphenylnitrilimins (1983)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 116 (1983), S. 3062-3070 
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    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: 1,3-Dipolar Cycloadditions, 89. New Contributions to the Chemistry of DiphenylnitrilimineMethyl propiolate, tetrolate, and phenylpropiolate combine with diphenylnitrilimine (1) to afford regioisomeric cycloadducts; the preferential orientation shifts in the sequence given from the pyrazole-5-carboxylic ester to the 4-carboxylic ester. Corresponding isomer ratios substantiate the occurrence of 1 in the reaction of (α-chlorobenzylidene)phenylhydrazine + triethylamine and in the photolysis or thermolysis of 2,5-diphenyltetrazole. - Chloroethylenes and 1 furnish 5-chloropyrazolines which eliminate HCl. - The sodium salt of (α-nitrobenzylidene)phenylhydrazine likewise is a source of 1. The electrophilic propiolic ester gives rise to an adduct mixture which is richer in methyl 1,3-diphenylpyrazole-4-carboxylate than that characteristic of 1, thus suggesting a second reaction pathway.
    Notes: Propiolsäure-, Tetrolsäure- und Phenylpropiolsäureester treten mit Diphenylnitrilimin (1) zu den beiden regioisomeren Cycloaddukten zusammen, wobei sich die Vorzugsorientierung in der genannten Folge vom Pyrazol-5-carbonsäureester zum -4-carbonsäureester verschiebt. Gleiche Isomerenverhältnisse belegen das Auftreten von 1 bei der Reaktion des (α-Chlorbenzyliden)-phenylhydrazins mit Triethylamin sowie bei der Photolyse oder Thermolyse des 2,5-Diphenyltetrazols. - Chlorierte Ethylene vereinigen sich mit 1 zu 5-Chlorpyrazolinen, die HCl abgeben. - Auch das Natriumsalz des (α-Nitrobenzyliden)phenylhydrazins bietet eine Quelle für 1. Abweichungen vom üblichen Orientierungsverhalten beobachtet man bei Propiolsäure-methylester; höhere Gehalte am 1,3-Diphenylpyrazol-4-carbonsäureester weisen auf einen zusätzlichen Reaktionsweg.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19831160906
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    Asymmetrische Michael-Additionen. Regio-, diastereo- und enantioselektive Alkylierungen der Enamine aus β-Tetralonen und (S)-2-(Methoxymethyl)pyrrolidin („Prolinolmethylether“) durch ω-Nitrostyrole (1983)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 116 (1983), S. 3086-3096 
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    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Asymmetric Michael Additions. Regio-, Diastereo-, and Enantioselective Alkylations of the Enamines from β-Tetralones and (S)-2-(Methoxymethyl)pyrrolidine („Prolinol Methyl Ether“) by ω-Nitrostyrenesβ-Tetralones with various substitutents (CH3, NO2, OCH3, OCH2O, Cl) in 1-, 5-, 6-, 7- and 8-position are added to ω-nitrostyrenes (2) through enamines (1) derived from (S)-2-(methoxymethyl)pyrrolidine. Hydrolysis of the primary adducts (3) yields (35-55%) β-tetralones 4 alkylated in the 3-position. These are all 〉 90% diastereomerically and 75-99% optically pure (see u-4 and Table 1). From results of earlier investigations it is inferred, that the present reaction occurs with relative topicity lk, ul-1, 4 (see 6), i.e. that the products 4 have (3S, 1′R)-configuration. This is compatible with the 1H NMR and CD spectra of the isolated products of type 4.
    Notes: β-Tetralone mit den verschiedensten Substituenten (CH3, NO2, OCH3, OCH2O, Cl) in 1-, 5-, 6-, 7- und 8-Stellung werden über die Enamine (1) mit (S)-2-(Methoxymethyl)pyrrolidin an ω-Nitrostyrole (2) addiert, was nach Hydrolyse der Primär-Addukte 3 mit 35-55% Ausbeute zu den in 3-Stellung alkylierten β-Tetralonen 4 führt. Diese Hauptprodukte der Reaktion bestehen zu über 90% (ds) aus den u-Diastereomeren mit 75-99% Enantiomerenüberschuß (ee), siehe Formel 4 und Tab. 1. Die Resultate früherer Untersuchungen lassen erwarten, daß auch die hier beschriebene Reaktion mit relativer Topizität lk, ul-1,4 abläuft (siehe 6), daß also die Produkte 4 (3S, 1′R)-Konfiguration besitzen. Dies ist mit den 1H-NMR- und CD-Spektren der Produkte vom Typ 4 vereinbar.
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    Nucleophile Addition von Triorganozinn-Anionen an Kohlenstoffdisulfid, VI. Substitutionsreaktionen an Tetracarbonyl(triphenylstannandi-thiocarboxylato-S,S′)mangan(I) mit σ-Donorliganden der V. Hauptgruppe (1983)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 116 (1983), S. 3071-3085 
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    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Nucleophilic Addition of Triorganotin Anions to Carbon Disulfide, VI. Substitution Reactions of Tetracarbonyl(triphenylstannanedithiocarboxylato-S,S′)manganese(I) with σ-Donor Ligands of Main Group VThe facial tricarbonyl complexes (CO)3-(L)MnS2CSnPh3 (2a: L = P(OPh)3, 2b: L = P(OMe)3, 2c: L = PPh3, 2d: L = AsPh3, 2e: L = SbPh3, 2f: L = P(c-C6H11)3) are obtained by thermal substitution of the tetracarbonylmanganese chelate complex (CO)4MnS2CSnPh3 (1) with VB donor ligands. With more bulky phosphane ligands, the meridional complexes 3f (L = P(c-C6H11)3, and 3g (L = Ph2PCH2CH2PPh2 (dppe)) are formed by photolytic and thermal substitution, respectively. 3f and g rearrange easily to the more stable facial isomers 2f and 5c. By extended thermal (L = P(OPh)3, P(OMe)3) or by photolytic reactions (L = PPh3, AsPh3, SbPh3) of 1 with the given ligands, the trans-disubstituted products 4a-e are obtained. The rearrangement 4d→2d was followed by UV spectroscopy and found to proceed in the stoichiometric ratio 3:2 with k = (1.14 ± 0.01)·10-4 s-1 (t = 25°C). Complexes with a monodentate stannanedithiocarboxylate ligand are synthesized by substitution of 1 with bidentate ligands (5c: L = dppe, 5d: L = dipy) or by metathesis of substituted carbonylmetal halides (5b′: L = PPh3, M = Re; 5e: 2 L = P(OPh)3 M = Mn). The results show that the thermal substitution is consistent with a dissociative mechanism while the photolytic substitution is assumed to require a ring opening of the chelate ligand.
    Notes: Durch thermische Substitution des Tetracarbonylmangan-Chelatkomplexes (CO)4MnS2CSnPh3 (1) mit Donorliganden der V. Hauptgruppe erhält man die facialen Tricarbonylkomplexe (CO)3-(L)MnS2CSnPh3 (2a: L = P(OPh)3, 2b: L = P(OMe)3, 2c: L = PPh3, 2d: L = AsPh3, 2e: L = SbPh3, 2f: L = P(c-C6H11)3). Dagegen werden mit sterisch anspruchsvolleren Phosphanliganden die meridionalen Komplexe 3f (L = P(c-C6H11)3, photochemisch) und 3g (L = Ph2PCH2CH2PPh2 (dppe), thermisch) gebildet, die sich leicht in die stabileren facialen Isomeren 2f bzw. 5c umlagern. Durch längere thermische Reaktion (L = P(OPh)3, P(OMe)3) oder photochemische Umsetzung (L = PPh3, AsPh3, SbPh3) von 1 mit den angegebenen Liganden entstehen die trans-Disubstitutionsprodukte 4a-e. Die Rückbildung 4d→2d wurde UV-spektroskopisch verfolgt und läuft im stöchiometrischen Verhältnis 3:2 mit k = (1.14 ± 0.01)·10-4 s-1 (t = 25°C) ab. Komplexe mit einzähnig koordiniertem Stannandithiocarboxylat-Liganden lassen sich durch Substitution von 1 mit zweizähnigen Liganden (5c: L = dppe, 5d: L = dipy) oder durch direkte Umsetzung substituierter Carbonylmetallhalogenide (5b′: L = PPh3, M = Re; 5e: 2 L = P(OPh)3, M = Mn) darstellen. Die Ergebnisse zeigen, daß sich die thermische Substitution mit einem Dissoziationsmechanismus vereinbaren läßt, während bei der photochemischen Substitution eine Ringöffnung des Chelatliganden anzunehmen ist.
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    Reaktionen von Carbonsäurechloriden mit cyclischen Kohlenwasserstoffen unter dem Einfluß ionisierender Strahlung (1983)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 116 (1983), S. 500-508 
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    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Reactions of Carboxylic Acid Chlorides with Cyclic Hydrocarbons under the Influence of Ionizing RadiationUnder the influence of ionizing radiation on carboxylic acid chlorides/cycloalkane solutions, acylcycloalkanes are formed besides the related aldehydes and bicycloalkanes. The reaction is studied thoroughly for the benzoyl chloride/cyclohexane system. A kinetic scheme is proposed in which ionisation of the hydrocarbon and the subsequent reactions of the cations and electrons are the primary steps. In particular, acyl radicals are postulated as intermediates. The preparative applicability of the reaction is discussed. (3-Methylbenzoyl)cyclopentane is prepared from 3-methylbenzoyl chloride/cyclopentane and propionylcyclooctane from propionyl chloride/cyclooctane.
    Notes: Unter dem Einfluß ionisierender Strahlung auf Lösungen von Carbonsäurechloriden in cyclischen Kohlenwasserstoffen entstehen Acylcycloalkane neben den entsprechenden Aldehyden und Bicycloalkanen. Am Beispiel des Systems Benzoylchlorid/Cyclohexen wird die Reaktion eingehend untersucht und ein kinetisches Schema vorgeschlagen. In diesem Schema sind die Ionisierung des Kohlenwasserstoffs und die nachfolgenden Reaktionen der Kationen und Elektronen die primären Schritte. Insbesondere werden Acylradikale als Zwischenprodukte postuliert. Die präparative Anwendbarkeit der Reaktion wird diskutiert. Aus 3-Methylbenzoylchlorid/Cyclopentan werden (3-Methylbenzoyl)cyclopentan und aus Propionylchlorid/Cyclooctan Propionylcyclooctan dargestellt.
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    URL: http://dx.doi.org/10.1002/cber.19831160210
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    Eine neue Synthese und Reaktionsverhalten von (Aminoethinyl)sulfiden (1983)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 116 (1983), S. 509-513 
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    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: A Novel Synthesis and Reactions of Aminoethynyl SulfidesReaction of the alkynide 2 with sulfur provides ready access to aminoethynyl sulfides 5 with different second substituents on the sulfide sulfur atom. Hydrolysis and cycloadditions with diphenylketene, phenyl isocyanate, or tosyl isothiocyanate prove the S-alkyl derivatives 5a, b to be typical ynamines, whereas amine addition to the silylthio compound 5c takes a different course.
    Notes: Über die Reaktion des Alkinids 2 mit Schwefel lassen sich in einfacher Weise (Aminoethinyl)sulfide 5 mit verschiedenen Zweitsubstituenten am Sulfid-Schwefel erhalten. In der Hydrolyse und in Cycloadditionen mit Diphenylketen, Phenylisocyanat oder Tosylisothiocyanat erweisen sich die S-Alkyl-Derivate 5a, b als typische Inamine, während die Amin-Addition an die Silylthio-Verbindung 5c einen abweichenden Verlauf nimmt.
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    URL: http://dx.doi.org/10.1002/cber.19831160211
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    Übergangsmetall-Schwefelylid-Komplexe, XV. Synthese von 2H-Thiopyranchromkomplexen aus Tetraethylammonium-tricarbonyl(η5-3,5-diphenyl-1- thiacyclohexadienyl-1-oxid)chromat und harten Elektrophilen (1983)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 116 (1983), S. 514-521 
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    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Transition Metal Sulfur Ylide Complexes, XV. Synthesis of 2H-Thiopyran Chromium Complexes from Tetraethylammonium Tricarbonyl- (η-3,5-diphenyl-1-thiacyclohexadienyl 1-oxide)chromate and Hard ElectrophilesThe reactions of tetraethylammonium tricarbonyl(η5-3,5-diphenyl-1-thiacyclohexadienyl 1-oxide)chromate (2a) with methyl fluorosulfonate and N-sulfinyldimethylimmonium tetrafluoroborate, respectively, yield the 2H-thiopyran complexes 4 and 9 instead of the expected λ4-thiabenzene complexes 3 and 8. The molecular structure of 9 was elucidated by X-ray analysis.
    Notes: Bei der Reaktion von Tetraethylammonium-tricarbonyl(η5-3,5-diphenyl-1- thiacyclohexadienyl-1-oxid)chromat (2a) mit Fluorsulfonsäure-methylester bzw. N-Sulfinyldimethylimmonium-tetra-fluoroborat werden statt der erwarteten λ4-Thiabenzolkomplexe 3 und 8 die dazu isomeren 2H-Thiopyrankomplexe 4 und 9 isoliert. Die Molekülstruktur von 9 wurde durch Röntgenstrukturanalyse aufgeklärt.
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    Zur Konfiguration der 1,3-Dichlor-2-methyl-1-propene (1983)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 116 (1983), S. 522-526 
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    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: On the Configuration of the 1,3-Dichloro-2-methyl-l-propenesDetermination of the configurations of 1,3-dichloro-2-methyl-1-propenes (1) was performed by 1H and 13C NMR spectroscopy using the isomer pairs of 1,3-dichloro-1-propenes (2), 1-chloro-2-methyl-1-propene-3-ols (3) and 1-chloro-1-propene-3-ols (4) as reference compounds. The chemical shifts, vicinal coupling constants, relative LIS value and NOE effects were in an unambiguous agreement with the (Z)-configuration of the lower-boiling isomer of 1.
    Notes: Die Konfigurationen von 1,3-Dichlor-2-methyl-1-propenen (1) werden mittels 1H- und 13C-NMR-Spektroskopie zugeordnet. Als Vergleichssubstanzen dienten die Isomeren von 1,3-Dichlor-1-propen (2), 1-Chlor-2-methyl-1-propen-3-ol (3) und 1-Chlor-1-propen-3-ol (4). Die chemischen Verschiebungen, vicinalen Kopplungskonstanten, relativen LIS-Werte und NOE-Effekte stehen mit der (Z)-Konfiguration des niedriger siedenden Isomeren von 1 eindeutig im Einklang.
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    Kristall- und Molekularstruktur von zwei [24]Cyclophanen:[24](1,2,3,4)Cyclophan und [24](1,2,3,5)Cyclophan (1983)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 116 (1983), S. 527-535 
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    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Crystal and Molecular Structures of two [24]Cyclophanes: [24](1,2,3,4)Cyclophane and [24](1,2,3,5)CyclophaneThe benzene rings of the two [24]cyclophanes [24](1,2,3,4)cyclophane (1) and [24](1,2,3,5)cyclophane (2) show a boat-like (1) and a sofa-like (2) distortion from planarity. Because of interring repulsion the central C—C bonds of the ethano groups are stretched to 1.561-1.593 Å.
    Notes: Die Bestimmung der Kristall- und Molekularstrukturen der beiden [24]Cyclophane [24](1,2,3,4)-Cyclophan (1) und [24](1,2,3,5)Cyclophan (2) ergaben für die Phenylringe eine wannenförmige bzw. sofaförmige Deformation. Die abstoßenden Wechselwirkungen zwischen den Phenylringen bewirken weiterhin eine Dehnung der zentralen C—C-Bindungen der Ethanogruppen auf 1.561-1.593 Å.
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    1-Acyl-4-alkyliden-1,4-dihydropyridine, 7. Aktivierung durch Bortrifluorid: Intermolekulare Acylgruppenübertragung unter Bildung von 1-(4-Pyridyl)-2-alkanonen (1983)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 116 (1983), S. 3192-3204 
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    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: 1-Acyl-4-alkylidene-1,4-dihydropyridines, 7. Activation with Boron Trifluoride, Intermolecular Acyl Group Transfer and Formation of 1-(4-Pyridyl)-2-alkanones1-Acyl-4-alkylidene-1,4-dihydropyridines 5, representatives of the thermally stable enamides, can be activated by means of boron trifluoride 6, so the ketones 7 result from attack of 6 on 5 (intermolecular acyl group transfer). The mechanism of this reaction, which has not previously been observed for enamides, is strongly suggested to be as follows: 5 and 6 form first the adduct 21, which attacks 5 with formation of 27. Special examples of 5 (11 and 12) are found to be reactive enough that the ketone 7h or the sulfone 15 can be obtained from their isolable precursors (14 and 13) without Lewis-acid activation. 13 is particularly noteworthy: being the precursor of the salt 16, which is generated in situ, it serves as an extremely effective tosylating agent. Even tertiary alcohols are attackted by 16.
    Notes: 1-Acyl-4-alkyliden-1,4-dihydropyridine 5 - zur Klasse der thermisch sehr stabilen Enamide gehörend - können mittels Bortrifluorid 6 aktiviert werden, so daß nach Angriff von 6 auf 5 die Ketone 7 entstehen (intermolekulare Acylgruppenübertragung). Der Mechanismus dieser bei Enamiden bisher nicht beobachteten Reaktion wird weitgehend aufgeklärt: Aus 5 entsteht mit 6 zunächst das Addukt 21, das 5 unter Bildung von 27 angreift. - Spezielle Beispiele für 5(11 und 12) erweisen sich als hinreichend reaktiv, so daß ohne deren Lewis-Säure-Aktivierung das Keton 7h bzw. das Sulfon 15 aus ihren isolierbaren Vorstufen 14 bzw. 13 erhalten werden. Besondere Beachtung verdient 13: als Vorstufe des in situ erzeugbaren Salzes 16 dient es als hochwirksames Tosylierungsreagenz. Selbst tertiäre Alkohole werden durch 16 angegriffen.
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    Zur Reaktivität geometrisch fixierter Vinylaziridine: Synthese und Thermolyse einiger 3,4-Epiminocyclohexene (1983)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 116 (1983), S. 563-586 
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    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Reactivity of Geometrically Fixed Vinylaziridines: Synthesis and Thermolysis of Several 3,4-EpiminocyclohexenesThe aminoalcohols 13-16, readily accessible by aminolysis of the oxiranes 5 and 6, are transformed into the epiminocyclohexenes 17-20 using triphenylphosphane/tetrachloromethane as cyclisation reagent. While the N-benzyl-monocarboxylate 17 is thermally quite unstable and undergoes a homodienyl-H-shift to give the imine 23 already at 100°C, the N-phenyl derivative 18 reacts only at 370°C under short-time pyrolysis conditions leading to the isomeric pyrroles 24 and 25. The formation of the fragmentation products is explained by a competitive C/N- and C/C-ring cleavage as the first step. On heating the dimethyldicarboxylate-substituted vinylaziridines 19 and 20 at about 100°C ring expansion reactions take place affording the 2,3-dihydroazepines 32 and 34, respectively; in the case of 19 also the imine 33 is formed to a minor extent. As the mechanism of the transformations 19(20) → 32(34) a direct (1,5)-H-shift has to be excluded on the basis of H/D-exchange experiments. An alternative reaction sequence is proposed with the ester enol 35 as central intermediate, which may be formed either by a homotrienyl-H-shift from 19(20) or - after C/C-ring opening to the respective conjugated azomethine ylides - by (1,8)-H-migration. Trapping experiments with 19 and 20 point to the last mentioned possibility because the 1,3-dipolar-cycloadducts 47 and 48 are formed four times faster than the isomerisation products. Addition of dimethyl acetylenedicarboxylate to the monosubstituted epiminocyclohexenes 17/18 affords the homo-Diels-alder-adducts 44/45.
    Notes: Die durch Aminolyse der Oxirane 5 und 6 zugänglichen Aminoalkohole 13-16 werden unter Verwendung von Triphenylphosphan/Tetrachlormethan als Cyclisierungsreagenz in die Epiminocyclohexene 17-20 übergeführt. Während der N-Benzyl-monoester 17 thermisch sehr instabil ist und schon bei ca. 100°C durch Homodienyl-H-Verschiebung in das Imin 23 übergeht, reagiert der N-Phenyl-monoester 18 erst unter Kurzzeitthermolysebedingungen bei 370°C unter Bildung der Pyrrole 24 und 25. Die Entstehung der Fragmentierungsprodukte wird über eine einleitende kompetitive C/N- und C/C-Ringspaltung erklärt. Beim Erhitzen der diestersubstituierten Vinylaziridine 19 und 20 findet bei ca. 100°C eine Ringerweiterung zu den 2,3-Dihydroazepinen 32 bzw. 34 statt sowie im Falle von 19 noch zu geringem Anteil die Bildung des Imins 33. Als Mechanismus der Umwandlungen 19(20) → 32(34) ist eine direkte (1,5)-H-Wanderung auf Grund von H/D-Austauschexperimenten auszuschließen. Als Alternativen werden Reaktionswege über das Ester-Enol 35 diskutiert, das entweder über eine Homotrienyl-H-Verschiebung aus 19(20) entstanden ist oder nach einleitender C/C-Ringspaltung aus den entsprechenden konjugierten Azomethin-Yliden durch (1,8)-H-Wanderung. Zugunsten der letzteren Möglichkeit sprechen Abfangversuche, bei denen die 1,3-dipolaren Cycloaddukte 47 und 48 ca. viermal rascher als die Umlagerungsprodukte gebildet werden. Die Epiminocyclohexen-monoester 17, 18 reagieren mit Acetylendicarbonsäure-dimethylester unter Bildung der Homo-Diels-Alder-Addukte 44/45.
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    Diademan und Strukturverwandte, I. Darstellung und charakteristische Reaktionen einiger Tris-σ-homobenzol-Kohlenwasserstoffe (1983)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 116 (1983), S. 587-609 
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    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Diademane and Structurally Related Compounds, I Preparation and Characteristic Reactions of Some Tris-σ-homobenzene HydrocarbonsDiademane (5) and 1,6-Homodiademane (6) are the first hydrocarbons with cis-tris-σ-homobenzene skeletons. They were prepared by photoisomerization of the olefinic precursors 8 („snoutene“) and 15 („4,5-homosnoutene“), respectively. In an analogous reaction the bridged trans-tris-σ-homobenzene 7 was formed from 17 („endo,exo-bishomobarrelene“). 7 is more easily obtained from 17 by rhodium(I)-catalyzed isomerization or from exo,exo-bishomobarrelene 18 by thermal rearrangement. The unbridged 4 was prepared using a newly developed synthetic sequence starting from 1,3-cyclohexadiene. The thermal rearrangement of 5 and 6 to triquinacene (9) and 1,10-homotriquinacene (16) is very facile; the gas phase kinetic parameters (ln k (5) = 33.7 - 31600/RT and ln k (6) = 32.2 - 28300/RT, both first order) strongly corroborate, that these rearrangements are concerted [σ2a + σ2a + σ2s]-Cycloreversions. [3,6-12C2]-labelled 4 upon thermolysis yields a trans-bicyclo[4.3.0]nona-3,7-diene (31 ≙ 22) with a 12C-labelling pattern, which proves its formation via a 3-step mechanism. The first step in this sequence most probably is a [σ2s + σ2s + σ2a] cycloreversion with ln k = 30.8 - 42000 RT(first order). Only the bridged compound 7 does not follow the same path, probably due to excessive ring strain in the transition state, and prefers a stepwise [2 + 2] cycloreversion leading to 18 and at least 5 secondary products.
    Notes: Diademan (5) und 1,6-Homodiademan (6), die ersten Kohlenwasserstoffe mit cis-Tris-σ-homo-benzol-Gerüst, wurden durch Photoisomerisierung der monoolefinischen Vorstufen 8 („Snouten“) bzw. 15 („4,5-Homosnouten“) gewonnen. Analog entstand aus 17 („endo,exo-Bis-homobarrelen“) das überbrückte trans-Tris-σ-homobenzol 7, das sich bequemer auch durch Rhodium(I)-katalysierte Isomerisierung von 17, oder thermische Umlagerung von exo,exo-Bishomobarrelen 18 erhalten ließ. Das nicht überbrückte 4 wurde nach einer neuen Synthesesequenz aus 1,3-Cyclohexadien dargestellt. Thermisch lagern sich 5 und 6 sehr leicht in Triquinacen (9) bzw. 1,10-Homotriquinacen (16) um, die gasphasen-kinetischen Parameter (In k (5) = 33.7 - 31600/RT und in k (6) = 32.2 - 28300/RT, beide 1. Ordnung) lassen auf konzertiert verlaufende [σ2s + σ2s + σ2s]-Cycloreversionen schließen. [3,6-12C2]-markiertes 4 liefert bei der Thermolyse ein trans-Bicyclo[4.3.0]nona-3,7-dien (31 ≙ 22) mit einem 12C-Markierungsmuster, das einen dreistufigen Bildungsmechanismus beweist. Dabei ist der erste Schritt wahrscheinlich eine [σ2s + σ2s + σ2s]-Cycloreversion mit ln k = 30.8 - 42000/RT (1. Ordnung). Nur das überbrückte 7 weicht diesem Umlagerungstyp aus und erfährt - offenbar aus Gründen der Ringspannung - eine schrittweise verlaufende [2 + 2]-Cycloreversion zu 18 und mindestens 5 Folgeprodukten.
    Additional Material: 6 Tab.
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    URL: http://dx.doi.org/10.1002/cber.19831160219
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    Cyclovinyloge Additionen von 1,3-Diphenylbenzo[c]furan an 1,3,5-Cycloheptatrien (1983)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 116 (1983), S. 618-629 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Cyclovinylogous Additions of 1,3-Diphenylbenzo[c]furan to 1,3,5-Cycloheptatriene1,3-Diphenylbenzo[c]furan (1) reacts thermally with 3,4-dimethylenecyclobutene (2) and 1,3,5-cycloheptatriene (5) to give exo- and endo-Diels-Alder adducts. The reaction of 1 with potassium cycloheptatrienide leads to substitutive adducts (13, 14) at low temperature, but to [4 + 2]-ring closure (15) at higher temperatures, via the anionic intermediate 12. The photoaddition of 1 to 5 gives the exo- and endo-[4 + 2]-, endo-[4 + 6]-, exo-[4 + 4]- und cis-1,4(1,3)-substitutive adducts 7, 6, 16, 17 und 14, in divergence to recent literature data. The structures of the products are elucidated by 1H NMR spectra and in part by chemical transformations, their formation can be interpreted in terms of the approved diradical mechanism. The endo-/exo-isomerization of 16 into 19 proceeds solvolytically. The products 7 and 16 are formed out of 17 by suprafacial thermal 1,3-alkyl shifts. Further exo- und endo-[4 + 2]- as well as [4 + 4]-additions of 1 are achieved with dimethyl maleate (23, 24) and anthracene (26), resp.
    Notes: 1,3-Diphenylbenzo[c]furan (1) reagiert thermisch mit 3,4-Dimethylencyclobuten (2) und 1,3,5-Cycloheptatrien (5) zu exo- und endo-Diels-Alder-Addukten. Die Reaktion von 1 mit Kaliumcycloheptatrienid führt über das Anionzwischenprodukt 12 bei tiefer Temperatur zu Substitutionsaddukten (13, 14), bei höherer Temperatur dagegen zum [4 + 2]-Ringschluß (15). Die Photoaddition von 1 an 5 führt abweichend von Literaturangaben zu den exo- und endo-[4 + 2]-, endo-[4 + 6]-, exo-[4 + 4]- und cis-1,4(1,3)-Substitutions-Addukten 7, 6, 16, 17 und 14, deren Konstitution 1H-NMR-spektroskopisch sowie z. T. durch chemische Umwandlungen belegt wird und deren Bildung auf der Grundlage des bewährten Diradikalmechanismus gedeutet werden kann. Die endo-/exo-Isomerisierung von 16 zu 19 gelingt solvolytisch. Durch suprafaciale thermische 1,3-Alkylverschiebungen entstehen aus 17 die Produkte 7 und 16. Weitere exo- und endo-[4 + 2]- sowie [4 + 4]-Additionen von 1 werden mit Maleinsäure-dimethylester (23, 24) und Anthracen (26) erreicht.
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    Methylenschwefeltetrafluorid, CH2=SF4, Darstellung, Struktur und Chemie (1983)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 116 (1983), S. 645-658 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Methylenesulfurtetrafluoride, CH2=SF4 Formation, Structure, and ChemistryThe preparation of methylenesulfurtetrafluoride, CH2=SF4, is achieved by bromine-lithium exchange on Br—CH2—SF5 at low temperatures and subsequent lithium fluoride elimination. CH2=SF4 is a colourless gas with b.p. -19°C and m.p. -139°C. The structure is essentially trigonal-bipyramidal, the methylene group occupying an equatorial position. The protons lie in the plane of the axial fluorine atoms. The molecule is rigid. The carbon-sulfur bond is best described as strong double bond with only little ylidic polarity. - The double bond undergoes numerous addition reactions with polar species under formation of cis-configurated X—CH2—SF4—Y systems. Less often elimination of SF4 and formation of carbene is observed.
    Notes: Die Darstellung von Methylenschwefeltetrafluorid, CH2=SF4, gelingt durch Brom-Lithium-Austausch am Br—CH2—SF5 bei tiefen Temperaturen und anschließende Lithiumfluorid-Eliminierung. CH2=SF4 ist ein farbloses Gas vom Siedepunkt -19°C und Festpunkt -139°C. Seine Struktur ist angenähert trigonal-bipyramidal mit äquatorialer Stellung der Methylengruppe und Koplanarität der Wasserstoffatome mit den axialen Fluoratomen. Das Molekül ist vollkommen starr. Die Bindung zur Methylengruppe wird am besten als Doppelbindung mit nur geringer ylidischer Polarität beschrieben. - Die Doppelbindung geht zahlreiche Additionsreaktionen mit polaren Reaktanten ein, wobei es ausschließlich zur Ausbildung cis-konfigurierter Systeme X—CH2—SF4—Y kommt. Eine seltenere Reaktionsweise ist die Eliminierung von SF4 unter intermediärer Freisetzung von Carben.
    Additional Material: 1 Tab.
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    URL: http://dx.doi.org/10.1002/cber.19831160223
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    Photoadditionen von Anthracenen an 2,4-Hexadien und 1,3,5-Cycloheptatrien (1983)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 116 (1983), S. 630-644 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Photoadditions of Anthracenes to 2,4-Hexadiene and 1,3,5-CycloheptatrieneElectronically excited 9-anthracenecarbonitrile (1*), in contrast to theoretical predictions, is trapped by 2,4-hexadiene to give the [4 + 4]-adduct 3 with a trans-double bond, which forms the [4 + 2]-adduct 4 above 0°C via suprafacial 1,3-shift. Also 1,3,5-cycloheptatriene (6) quenches 1* with the result of a thermolabile [4 + 4]-addukt 7 (→ 8). In addition to 8, further adducts (9, 10, 11, 12) are formed via isomeric diradicals. Anthracene (19*) and 6 generate the [4 + 6]-, [4 + 4]-, [4 + 2]-, substitutive, and peripheral adducts 20, 21, 22, 23, 24, and 24. 9-Phenylanthracene (25*) and 6 form the corresponding, partly isomeric, adducts (26; 29; 27, 28; 30, 31; 32). The reactions are interpreted in terms of diradical mechanisms. Numerous literature reports, which havealready been classified theoretically, are amended or corrected, the reasons for erroneous theoretical predictions are discussed. The diversity of products can be understood in detail by empirical extrapolations on the basis of the experimentally secured cyclovinylogy principle.
    Notes: Elektronisch angeregtes 9-Anthracencarbonitril (1*) wird von 2,4-Hexadien (2) entgegen theoretischen Erwartungen zum [4 + 4]-Addukt 3 mit trans-Doppelbindung abgefangen, aus dem oberhalb 0°C durch suprafaciale 1,3-Verschiebung das [4 + 2]-Addukt 4 entsteht. Auch 1,3,5-Cycloheptatrien (6) reagiert mit 1* zu einem thermolabilen [4 + 4]-Addukt 7 (→ 8). Daneben entstehen weitere Addukte (9, 10, 11, 12) über isomere Diradikale. Anthracen (19*) bildet mit 6 die [4 + 6]-, [4 + 4]-, [4 + 2]-, Substitutions- und Peripher-Addukte 20, 21, 22, 23, 24. Mit 9-Phenylanthracen (25*) und 6 gibt es die entsprechenden, z. T. stellungsisomeren, Addukte (26; 29; 27, 28; 30, 31; 32). Die Reaktionen werden an Hand von Diradikalmechanismen gedeutet. Zahlreiche bereits theoretisch klassifizierte Literaturangaben werden ergänzt oder berichtigt, die Gründe für die fehlerhaften theoretischen Vorhersagen diskutiert. Die Produktevielfalt kann durch empirische Extrapolation im Rahmen des experimentell gesicherten Cyclovinylogieprinzips detailliert verstanden werden.
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    Reaktionen von Glycinato-Verbindungen von Platin(II), Palladium(II) und Kupfer(II) mit Amidacetalen: Schiffbase-Komplexe (1983)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 116 (1983), S. 659-668 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Reactions of Glycinato Compounds of Platinum(II), Palladium(II), and Copper(II) with Amide Acetals: Schiff Base ComplexesA series of Schiff base complexes of platinum(II), palladium(II), and copper(II) 1-4 has been obtained from glycinato chelate compounds and amide acetals. The structure of the complexes has been determined by their IR and NMR spectra, that of 3a by an X ray structure analysis. With trans-bis(glycinato)platinum(II) also reaction with DMF at the α-methylene group of a glycinate ligand has been observed to give a serine derivative as ligand (5), the Schiff base complex 2a being isolated as intermediate. The first step of these reactions always is an attack of the amide acetal at the amino group; the coordinated and activated Schiff base ligands may also react at the α-methylene group.
    Notes: Eine Reihe von Schiffbase-Komplexen von Platin(II), Palladium(II) und Kupfer(II) 1-4 wird aus Glycinato-Chelatkomplexen und Amidacetalen erhalten. Die Struktur der Verbindungen wird spektroskopisch, die von (3a) durch Röntgenstrukturanalyse bestimmt. Bei trans-Bis(glycinato)platin(II) wird mit DMF auch Reaktion an der α-Methylengruppe eines Glycinat-Linganden unter Bildung eines Serinderivats als Liganden (5) beobachtet, wobei der Bis(Schiffbase)-Komplex 2a als Zwischenprodukt isoliert werden kann. Amidacetale greifen (Glycinato)platin(II)-Komplexe primär stets an der Aminogruppe an, erst im zweiten Schritt kann die Reaktion an der α-Methylengruppe des koordinierten Schiffbase-Liganden erfolgen.
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    URL: http://dx.doi.org/10.1002/cber.19831160224
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    Über die Reduktion des Benzvalenozonids zum cis-1,3-Cyclobutandimethanol mit LiAlH4 (1983)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 116 (1983), S. 669-680 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: On the Reduction of Benzvalene Ozonide to cis-1,3-Cyclobutanedimethanol with LiAIH4On treatment with LiAlH4 at -30°C the polymeric ozonide of benzvalene (1) gives bicyclo-[1.1.0]butane-endo,endo-2,4-dimethanol (7). At higher temperatures cis-1,3-cyclobutanedimethanol (4) is formed. The stereochemical course of this unusual C—C hydrogenolysis has been elucidated by means of deuterated substrates. For this purpose a complete analysis of the 1H NMR spectra of the labeled cis-1,3-cyclobutanedicarboxylic anhydrides 9a-c had to be carried out. The dialcohol 7 and its bismethyl ether 16 add thiophenol across the central bond to form the cis products 18 and 19, respectively. Acids or Ag+ ions isomerize 7 via cleavage of a lateral bond into the ethers 21.
    Notes: Das polymere Ozonid des Benzvalens (1) wird mit LiAlH4 bei -30°C in Bicyclo[1.1.0]butan-endo,endo-2,4-dimethanol (7) übergeführt, bei höherer Temperatur entsteht cis-1,3-Cyclobutan-dimethanol (4). Mit deuterierten Verbindungen wurde der stereochemische Ablauf dieser ungewöhnlichen C—C-Hydrogenolyse aufgeklärt. Dazu mußte eine vollständige Analyse der 1H-NMR-Spektren der markierten cis-1,3-Cyclobutandicarbonsäureanhydride 9a-c durchgeführt werden. 7 und sein Bismethylether 16 addieren an der zentralen Bindung Thiophenol zu den cis-Produkten 18 bzw. 19. Säure oder Ag+-Ionen überführen 7 unter Öffnung einer seitlichen Bindung in die Ether 21.
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    URL: http://dx.doi.org/10.1002/cber.19831160225
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