ALBERT

All Library Books, journals and Electronic Records Telegrafenberg

X
feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
  • 1
    Electronic Resource
    Electronic Resource
    The microtubule cytoskeleton and the rounding of isolated generative cells ofNicotiana tabacum (1992)
    Springer
    Sexual plant reproduction 5 (1992), S. 64-71 
    Details
    ISSN: 1432-2145
    Keywords: Generative cell ; Isolation ; Microtubules ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Upon squashing of the pollen grain, the isolated generative cell ofNicotiana tabacum looses its spindle shape to become spherical; this phenomenon is independent of the sucrose concentration used. The time necessary for this change can vary from 1 min (0% sucrose) to 20 min (30% sucrose). The microtubular cytoskeleton was studied by means of immunofluorescence and electron microscopy. Just after isolation, 5 to 15 clearly visible bundles in microtubules organized in a basket-like structure are present. After 15 min in medium with 15% sucrose, the microtubular cytoskeleton disappears, and a diffusely spread tubulin can be observed. Neither the addition of 10–20 μM taxol to the medium, nor the omission of Ca2+ to the medium has any effect on the changes in cell shape and loss of microtubular bundles after isolation.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00714559
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 2
    Electronic Resource
    Electronic Resource
    Isolation of sperm cells from mature pollen grains of Spinacia oleracea L. (1989)
    Springer
    Sexual plant reproduction 2 (1989), S. 97-102 
    Details
    ISSN: 1432-2145
    Keywords: Sperm cell isolation ; Pollen ; Spinacia oleracea
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary When mature pollen grains of Spinacia oleracea were squashed in a 25% sucrose solution and subsequently centrifuged on a percoll layer, sperm cells were isolated in high numbers. All steps were carried out at 4° C. Isolated sperm cells could be kept alive for several hours.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00191997
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 3
    Electronic Resource
    Electronic Resource
    Isolation of male and female gametes in higher plants (1991)
    Springer
    Sexual plant reproduction 4 (1991), S. 145-154 
    Details
    ISSN: 1432-2145
    Keywords: Angiosperm gametes ; Egg cell ; Embryosac ; Gamete isolation ; Gametophytic cells ; Sperm cells ; Generative cells
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The availability of generative cells, sperm cells, embryo sacs and egg cells from angiosperm plants in isolated conditions has opened up many prospects: study of the mechanism of recognition and fusion between gametes of opposite sex and detailed observation of the process of fertilization, biochemical and genetic analysis of gamete-specific components and genetic engineering in combination with in vitro fertilization. This review provides a list of about ninety publications, in which the isolation of male or female angiosperm gametes and the closely related generative cells and embryo sacs is reported. The species used are summarized in two tables. A description is given of the diverse isolation techniques, which consist of enzymatic digestion, bursting of pollen by osmotic shock, squashing, grinding and micro-dissection. Viability of isolated cells and yield, two important aspects of biotechnological manipulation, are emphasized. A critical evaluation of the most significant results obtained so far with isolated material is presented together with notes on prospects for the future.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00189998
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 4
    Electronic Resource
    Electronic Resource
    Freeze-fracture studies on isolated sperm cells ofSpinacia oleracea L. (1990)
    Springer
    Protoplasma 153 (1990), S. 204-207 
    Details
    ISSN: 1615-6102
    Keywords: Spinacia oleracea ; Isolation ; Sperm cell membrane ; Intramembrane particles ; Freeze-fracture
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary With freeze-fracturing sperm cells appear to be fractured preferentially through the plasma membranes. Only few fracture planes through the cytoplasm are found. Both the PF as well as the EF side of the sperm cell plasma membranes show a slightly undulating surface and contain intramembrane particles. The particle distribution is irregular and does not show any clustering. The EF side of the plasmamembrane contains approximately 3 times more particles per μm2 than the PF side.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01354005
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 5
    Electronic Resource
    Electronic Resource
    Ultrastructural analysis ofSpinacia oleracea sperm cells isolated from mature pollen grains (1990)
    Springer
    Protoplasma 158 (1990), S. 176-181 
    Details
    ISSN: 1615-6102
    Keywords: Spinacia oleracea ; Sperm cell ultrastructure ; Morphometric analysis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary In isolated condition, the sperm cells ofSpinacia oleracea are no longer arranged in pairs as in the pollen grain. The vegetative membrane, which surrounds a sperm cell pair in a mature pollen grain, is lost during the isolation procedure. The sperm cells become spherical in shape. The isolated sperm cell is surrounded by an intact plasma membrane. The heterochromatic or euchromatic sperm cell nucleus is located in the cell center. Mitochondria are round to oval and have distinct cristae. Often they are clustered in groups of 5 to 10 mitochondria. Dictyosomes are present in the cytoplasm and consist of 4 to 5 cisterns. Endoplasmatic reticulum is mostly situated at the sperm cell periphery, as single cisterns very near the plasma membrane. From diameters of sectioned sperm cells in electron micrographs, it is possible to calculate the average diameter of the whole sperm cell. This average diameter is 3.66 μm with a variation of 3.0 μm to 4.2 μm, resulting in an average volume of 25.6 μm3. The nuclear volume is 12.8 μm3 (50.0% of the whole cell) and the mitochondrial volume is 0.7 μm3 (2.5% of the whole cell). The frequency distribution of the isolated sperm cells diameters shows only one peak with a normal distribution, indicating that there is no dimorphism in volume.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01323130
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 6
    Electronic Resource
    Electronic Resource
    Microtubule organization in sperm cells in the pollen tubes ofBrassica oleracea L. (1990)
    Springer
    Protoplasma 154 (1990), S. 151-156 
    Details
    ISSN: 1615-6102
    Keywords: Cytoskeleton ; Male gamete ; Motility
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Microtubules tightly cross-linked into bundles are described in the sperm cells ofBrassica oleracea pollen tubes. The sperm cells are lobed and “tailed” and the microtubule bundles are often located in these parts of the cells. In the present paper we suggest that the cross-linked microtubule organization could determine an intertubular sliding, probably generating a motility system that propels the sperm cells through the tube.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01539842
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...