ALBERT

All Library Books, journals and Electronic Records Telegrafenberg

feed icon rss

Your email was sent successfully. Check your inbox.

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

Proceed reservation?

Export
Filter
  • Crayfish  (2)
  • ddc:548
  • 1980-1984  (2)
Collection
Publisher
Years
Year
  • 1
    Electronic Resource
    Electronic Resource
    Springer
    Cell & tissue research 235 (1984), S. 387-392 
    ISSN: 1432-0878
    Keywords: Compound eye ; Structural asymmetries ; Crayfish
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The existence of structural asymmetries has been quantitatively demonstrated in the crayfish compound eye. Variations in the size of the rhabdomes and corneal facets, as well as the size and extent of the accessory reflecting pigment cells, have been found. It was determined that the mean rhabdome diameter within a 70° arc in the dorsal quadrant of the retina is 11–19% smaller than the mean rhabdome diameter in the remaining areas of the eye. Also, the extent of the accessory reflecting pigment cells is diminished over an area corresponding generally to the dorsal region of smaller rhabdomes. Corneal facet size and shape vary over the surface of the cornea, with smaller facets occurring in the dorsal region. Both the mean rhabdome diameter and the mean corneal facet area for whole eyes increases linearly in animals ranging in size from 3.9–12 cm. The estimated number of corneal facets, and therefore the number of rhabdomes, increases from an average of 4700 in the 3–6.9 cm size range to about 6000 in 7–12 cm animals. These data indicate that structural asymmetries and various size-related parameters exist in the crayfish eye and should be considered in any quantitative analysis of this structure.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 2
    Electronic Resource
    Electronic Resource
    Springer
    Cell & tissue research 206 (1980), S. 319-332 
    ISSN: 1432-0878
    Keywords: Crayfish ; Lysosome-related bodies ; Membrane turnover ; Photoreceptors
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The effect of illumination on the degradation of microvillar membrane in the invertebrate photoreceptor cell has been correlated with the appearance in the cytoplasm of certain distinct lysosome-related bodies. Three types of organelles were distinguished in the retinula cell cytoplasm of the crayfish, multivesicular bodies (MVB), both large (4.20-1.50 μm) and small (1.49-0.30 μm), combination bodies (CB), and lamellar bodies (LB). Under diurnal lighting conditions significant temporal differences were found in the appearance of these three classes of organelles in the retinula cell. Small MVB are present at a consistent level throughout most of the diurnal cycle but show peak numbers at 30 min after light onset and again after 6 h of dark adaptation. Large MVB increase significantly 1 h after light onset and remain elevated through 4 h in the light. After 4 h the large MVB decline gradually for the remaining light period. Combination bodies and LB do not begin to increase until 1 h after light onset and are at peak levels between 4 and 6 h into the light period. The minimum rhabdome diameter coincides with the peak levels of large MVB, CB, and LB. These data support the hypothesis that light causes microvillar membrane breakdown, resulting in the initial production of MVB which in turn undergo degradation to form CB and finally LB. This primary degradative response appears to be completed within the first 8 h of the light period.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...