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  • 1
    Electronic Resource
    Electronic Resource
    Agglutination factor in the cell body of Chlamydomonas eugametos (1983)
    Springer
    Planta 158 (1983), S. 403-409 
    Details
    ISSN: 1432-2048
    Keywords: Chlamydomonas (agglutination) ; Flagellum ; Glycoprotein (sexual agglutination factor) ; Sexual reproduction
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Chlamydomonas eugametos gametes agglutinate via the surfaces of their flagella. The mating-type minus (mt -) agglutination factor is a high-molecular-weight glycoprotein called PAS-1.2, present on the exterior surface of the flagellar membrane. During flagellar regeneration, mt - gametes were able to agglutinate as soon as the flagella protruded as short stumps. This was also observed when protein synthesis was blocked, indicating that gametes possess a pool of PAS-1.2. When the exterior surface of flagella-less gametes was extracted and the proteins were subjected to gel electrophoresis, large quantities of PAS-1.2 were detected. Using anti-PAS-1.2 serum, the presence of PAS-1.2-like material was visualized on the plasma membrane of mt - gamete cell bodies. By assaying the biological activity of extracts of the cell bodies and of isolated flagella, it was calculated that the plasma membrane of the cell bodies contains 25 times the activity present in the flagella and could, therefore, represent a large pool of mt - agglutination factor.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00397732
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  • 2
    Electronic Resource
    Electronic Resource
    Sexual agglutination in Chlamydomonas eugametos before and after cell fusion (1985)
    Springer
    Planta 166 (1985), S. 234-243 
    Details
    ISSN: 1432-2048
    Keywords: Cell fusion (Chlamydomonas gametes) ; Chlamydomonas (agglutination) ; Flagellum
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract A new study of sexual agglutination between Chlamydomonas eugametos gametes and between vis-à-vis pairs has been made using techniques that allow one to distinguish between the flagella or cell bodies of individual mating types (mt+ or mt-). It is shown that before mt+ and mt- gametes fuse in pairs, their flagella, which adhere over their whole length, are maintained in a particular conformation around the mt- cell body. In clumps of agglutinating gametes the cells are asymmetrically distributed with the mt+ gametes constituting the outer surface of the clumps with the mt- gametes on the inside. The flagella are then all directed towards the middle of the clump. This orientation of the flagella is maintained for approx. 8 min after cell fusion before the vis-à-vis pair becomes motile. At this stage, all the flagellar tips are activated. The original mt+ flagellar tips then deactivate and swimming is resumed. The original mt- flagella remain immotile and activated after cell fusion and eventually shorten by a third, but only 30 min or more after fusion. Motile vis-à-vis pairs eventually settle to the substrate when the gamete bodies fuse completely to form a zygote. Settling vis-à-vis pairs are attracted to those that have already settled, to glutaraldehyde-fixed pairs and to flagella isolated from mt- gametes. They are not chemotactically attracted, rather they are weakly agglutinated. Living vis-à-vis pairs can be shown to aggregate in rows with the cell bodies lying side by side. It is argued that the flagellar agglutination sites involved in gamete recognition are also involved in vis-à-vis pair aggregation
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00397354
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  • 3
    Electronic Resource
    Electronic Resource
    Evidence for a functional membrane barrier in the transition zone between the flagellum and cell body of Chlamydomonas eugametos gametes (1986)
    Springer
    Planta 167 (1986), S. 544-553 
    Details
    ISSN: 1432-2048
    Keywords: Chlamydomonas (agglutination) ; Flagellum ; Glycoprotein ; Membrane barrier
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Evidence is presented which supports the concept of a functional membrane barrier in the transition zone at the base of each flagellum of Chlamydomonas eugametos gametes. This makes it unlikely that agglutination factors present on the surface of the cell body can diffuse or be transported to the flagellar membrane. The evidence is as follows: 1) The glycoprotein composition of the flagellar membrane is very different to that of the cell-body plasma membrane. 2) The flagella of gametes treated with cycloheximide, tunicamycin or α, α′-dipyridyl become non-agglutinable but the source of agglutination factors on the cell body is not affected. 3) Even under natural conditions when the flagella are non-agglutinable, for example in vis-à-vis pairs or in appropriate cell strains that are non-agglutinable in the dark, the cell bodies maintain the normal complement of active agglutinins. 4) When flagella of living cells are labeled with antibodies bound to fluorescein, the label does not diffuse onto the cell-body surface. 5) When gametes fuse to form vis-à-vis pairs, the original mating-type-specific antigenicity of each cell body is slowly lost (probably due to the antigens diffusing over both cell bodies), while the specific antigenicity of the flagellar surface is maintained. Even when the flagella of vis-à-vis pairs are regenerated from cell bodies with mixed antigenicity, the antigenicity of the flagella remains matingtype-specific. 6) Evidence is presented for the existence of a pool of agglutination factors within the cell bodies but not on the outer surface of the cells.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00391231
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