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  • 1
    Electronic Resource
    Electronic Resource
    Calcium and Plant Development (1985)
    Palo Alto, Calif. : Annual Reviews
    Annual Review of Plant Physiology 36 (1985), S. 397-439 
    Details
    ISSN: 0066-4294
    Source: Annual Reviews Electronic Back Volume Collection 1932-2001ff
    Topics: Biology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1146/annurev.pp.36.060185.002145
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  • 2
    Electronic Resource
    Electronic Resource
    Microtubules and Microfilaments (1974)
    Palo Alto, Calif. : Annual Reviews
    Annual Review of Plant Physiology 25 (1974), S. 309-362 
    Details
    ISSN: 0066-4294
    Source: Annual Reviews Electronic Back Volume Collection 1932-2001ff
    Topics: Biology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1146/annurev.pp.25.060174.001521
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  • 3
    Electronic Resource
    Electronic Resource
    Changes of the actin filament system in the green algaMicrasterias denticulata induced by different cytoskeleton inhibitors (2000)
    Springer
    Protoplasma 212 (2000), S. 206-216 
    Details
    ISSN: 1615-6102
    Keywords: Cell shape formation ; Cytochalasin D ; Latrunculin B ; Micrasterias denticulata ; Oryzalin ; Phalloidin
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Two different techniques have been adapted forMicrasterias denticulata to depict the actin cytoskeleton of both untreated and inhibitor-treated developing cells: the “quickstaining method”, where the cells are fixed in a mixture of glutaraldehyde and formaldehyde followed by staining with phalloidin without embedding, and the “methacrylate method”, where the cells are also fixed by aldehydes and where the embedding medium is removed prior to incubation with an actin antibody. Both methods produce sufficient preservation and visualization of actin microfilaments (MFs) and confirm earlier observations on the presence of a cortical actin MF network in both the growing and the nongrowing semicell as well as of a basketlike MF arrangement around the migrating nucleus. The results show that a network of actin MFs is essential for the proper development of the young lobes ofM. denticulata. Early developmental stages expanding uniformly at the beginning of growth lack any netlike actin MF arrangement. The actin cytoskeleton in developing cells treated with the actin-targeting agents cytochalasin D and latrunculin B is markedly influenced. Cytochalasin D, which produces the most pronounced effects, causes a breakdown of the network of actin MFs, resulting in bright actin clusters as well as in short and abnormally thick actin fragments particularly in cortical cell regions. In latrunculin B-treated cells remnants of the former actin MF network are still visible, yet most of the actin cytoskeleton appears collapsed and is reduced to short filament pieces. The disturbance of the actin MF system visualized in the present study correlates with the severe morphological and ultrastructural changes occurring in desmid cells as a consequence of both drugs. The dinitroanilin herbicide oryzalin, known to deploymerize cytoplasmic microtubules, causes also an impairment of the actin cytoskeleton inM. denticulata though not sufficient to influence normal cell growth and differentiation.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01282921
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  • 4
    Electronic Resource
    Electronic Resource
    Model for Mitosis (1969)
    [s.l.] : Nature Publishing Group
    Nature 224 (1969), S. 659-663 
    Details
    ISSN: 1476-4687
    Source: Nature Archives 1869 - 2009
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Notes: [Auszug] Chromosome motion during mitosis can be explained by combining the facts available about the equilibrium between the mitotic spindle and its subunits with the postulate that the recently described cross-bridges between spindle microtubules are capable of sliding adjacent tubules over one ...
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1038/224659a0
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  • 5
    Electronic Resource
    Electronic Resource
    Hemmung der Kernmigration von Jochalgen (Micrasterias) durch Isopropyl-N-phenylcarbamat (1970)
    Springer
    Naturwissenschaften 57 (1970), S. 252-252 
    Details
    ISSN: 1432-1904
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology , Natural Sciences in General
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01010285
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  • 6
    Electronic Resource
    Electronic Resource
    Cellulose microfibril orientation and cell shaping in developing guard cells of Allium: The role of microtubules and ion accumulation (1976)
    Springer
    Planta 132 (1976), S. 71-93 
    Details
    ISSN: 1432-2048
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The role of microtubules and ions in cell shaping was investigated in differentiating guard cells of Allium using light and electron microscopy and cytochemistry. Microtubules appear soon after cytokinesis in a discrete zone close to the plasmalemma adjacent to the common wall between guard cells. The microtubules fan out from this zone, which corresponds to the future pore site, towards the other sides of the cell. Soon new cellulose microfibrils are deposited on the wall adjacent to the microtubules and oriented parallel to them. As the wall thickens, the shape of the cell shifts from cylindrical to kidney-like. Studies with polarized light show that guard cells gradually assume a birefringence pattern during development characteristic of wall microfibrils radiating away from the pore site. Retardation increases from 10 Å when cells just begin to take shape, to 80–100 Å at maturity. Both microfibril and microtubule orientation remain constant during development. Observations on aberrant cells including those produced under the influence of drugs such as colchicine, which leads to loss of microtubules, abnormal wall thickenings and disruption of wall birefringence, further support the role of microtubules in cell shaping through their function in the localization of wall deposition and the orientation of cellulose microfibrils in the new wall layer. Potassium first appears in guard mother cells before division and rapidly accumulates afterwards during cell shaping, as judged by the cobaltinitrite reaction. Some chloride and perhaps organic acid anions also accumulate. Thus, these ions, which are known to play a role in the function of mature guard cells, also seem to be important in the early growth and shaping of these cells.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00390333
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  • 7
    Electronic Resource
    Electronic Resource
    Changes in dye coupling of stomatal cells of Allium and Commelina demonstrated by microinjection of Lucifer yellow (1985)
    Springer
    Planta 164 (1985), S. 473-479 
    Details
    ISSN: 1432-2048
    Keywords: Allium (stomatal cells) ; Commelina ; Dye coupling ; Guard cell ; Lucifer yellow ; Plasmodesma
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Lucifer yellow has been microinjected into stomatal cells of Allium cepa L. epidermal slices and Commelina communis L. epidermal peels and the symplastic spread of dye to neighboring cells monitored by fluorescence microscopy. Dye does not move out of injected mature guard cells, nor does it spread into the guard cells when adjacent epidermal or subsidiary cells are injected. Dye does spread from injected subsidiary cells to other subsidiary cells. These results are consistent with the reported absence of plasmodesmata in the walls of mature guard cells. Microinjection was also used to ascertain when dye coupling ceases during stomatal differentiation in Allium. Dye rapidly moves into and out of guard mother cells and young guard cells. Hovewer, dye movement ceases midway through development as the guard cells begin to swell but well before a pore first opens. Since plasmodesmata are still present at this stage, the loss of symplastic transport may result from changes in these structures well in advance of their actual disappearance from the guard cell wall.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00395962
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  • 8
    Electronic Resource
    Electronic Resource
    A method for rapid freeze fixation of plant cells (1986)
    Springer
    Protoplasma 131 (1986), S. 153-165 
    Details
    ISSN: 1615-6102
    Keywords: Freeze substitution ; Hafnium tetrachloride ; Plant cell ultrastructure ; Rapid freeze fixation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary We describe here an apparatus that permits rapid freeze fixation of whole cells, which are then prepared by freeze substitution and resin embedment for examination in the EM. The freezing device utilizes a rotary solenoid that rapidly plunges the specimen holder, a formvar-film-covered thin wire loop, into a well of stirred liquid propane at −180
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01285037
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  • 9
    Electronic Resource
    Electronic Resource
    Ultrastructure of freeze-substitutedFrankia strain HFPCcI 3, the actinomycete isolated from root nodules ofCasuarina cunninghamiana (1985)
    Springer
    Protoplasma 127 (1985), S. 64-72 
    Details
    ISSN: 1615-6102
    Keywords: Actinomycete ; Casuarina ; Frankia ; Freeze-substitution ; Quick-freezing ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Frankia strain HFPCcI 3 is an actinomycete isolated from root nodules ofCasuarina cunninghamiana. In culture it exhibits typicalFrankia morphology and may produce three distinct morphological forms: branching septate hyphae, terminal or intercalary sporangia, and specialized structures termed vesicles which are the purported site of nitrogenase activity. An examination of the ultrastructure of all three morphological forms using both conventional chemical fixation (CF) and quick-freezing followed by freeze-substitution (FS) reveals some interesting differences between the two fixation methods. Unique to FS material are: 1. smooth membrane profiles; 2. lack of mesosomes; 3. lack of discernible nucleoid regions with condensed chromatin; 4. clarity of cytoplasmic elements such as ribosomes and granular bodies; 5. large cytoplasmic tubules in hyphae and young sporangia; 6. outer wall layer not widely separated from the spherical portion of the vesicle, and 7. bundles of microfilaments in vesicles. The quality of preservation after FS appears to be far superior to that obtained with CF. Accordingly the structures observed after FS are thought to represent more faithfully the structure of the living cell.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01273702
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  • 10
    Electronic Resource
    Electronic Resource
    Ultrastructure of the cytoskeleton in freeze-substituted pollen tubes ofNicotiana alata (1987)
    Springer
    Protoplasma 140 (1987), S. 141-150 
    Details
    ISSN: 1615-6102
    Keywords: Cytoskeleton ; Freeze substitution ; Nicotiana ; Pollen tubes ; Rapid freeze fixation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The ultrastructure of the cytoskeleton inNicotiana alata pollen tubes grownin vitro has been examined after rapid freeze fixation and freeze substitution (RF-FS). Whereas cytoplasmic microtubules (MTs) and especially microfilaments (MFs) are infrequently observed after conventional chemical fixation, they occur in all samples prepared by RF-FS. Cortical MTs are oriented parallel to the long axis of the pollen tube and usually appear evenly spaced around the circumference of the cell. They are always observed with other components in a structural complex that includes the following: 1. a system of MFs, in which individual elements are aligned along the sides of the MTs and crossbridged to them; 2. a system of cooriented tubular endoplasmic reticulum (ER) lying beneath the MTs, and 3. the plasma membrane (PM) to which the MTs appear to be extensively linked. The cortical cytoskeleton is thus structurally complex, and contains elements such as MFs and ER that must be considered together with the MTs in any attempt to elucidate cytoskeletal function. MTs are also observed within the vegetative cytoplasm either singly or in small groups. Observations reveal that some of these may be closely associated with the envelope of the vegetative nucleus. MTs of the generative cell, in contrast to those of the vegetative cytoplasm, occur tightly clustered in bundles and show extensive cross-bridging. These bundles, especially in the distal tail of the generative cell, are markedly undulated. MFs are observed commonly in the cytoplasm of the vegetative cell. They occur in bundles oriented predominantly parallel to the pollen tube axis. Although proof is not provided, we suggest that they are composed of actin and are responsible for generating the vigorous cytoplasmic streaming characteristic of living pollen tubes.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01273723
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