Document Detail

Fine structure of the ommatidia and the occurrence of rhabdomeric twist in the dorsal eye of male Bibio marci (Diptera, Nematocera, Bibionidae).
MedLine Citation:
PMID:  7214498     Owner:  NLM     Status:  MEDLINE    
The ommatidia in the dorsal eye of male Bibio marci (March flies) are comprised of eight retinula cells (R 1--8). In the distal region, the open rhabdomeres of retinula cells 1--6 are arranged in a symmetrically circular pattern with their microvilli directed radially. Immediately beneath the crystalline cone, cell 7 forms a rhabdomere that is about 1 micrometer long and lies in the center of the circle formed by the rhabdomeres of cells 1--6. For the remaining length of an ommatidium it is replaced by the rhabdomere of retinula cell 8. The cell body of this retinula cell almost encloses its own rhabdomere by forming a deep invagination. Consequently, no ommatidial cavity is present. In the left eye rhabdomeres R 3, 5 and 6 first twist clockwise along their longitudinal axes, while rhabdomeres R 1, 2, 4 and 8 twist counterclockwise. Opposite twisting is observed in the right eye. The twist rate varies along the length of the rhabdomeres. In a middle region of 60 micrometers, within which the direction of twist does not change, the maximal twist rates are approximately 2 degrees--5 degrees/micrometers in R 1--6 and even higher in R 8. In a proximal region, the direction of twist is reversed, but the initial orientation of the microvilli not reestablished. Both the cross-sectional shape of the rhabdomeres and their geometric arrangement in the retinula change along with the twisting. It is substantiated that the rhabdomeric twist is not due to artifactual deformation.
I Altner; D Burkhardt
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  Cell and tissue research     Volume:  215     ISSN:  0302-766X     ISO Abbreviation:  Cell Tissue Res.     Publication Date:  1981  
Date Detail:
Created Date:  1981-06-13     Completed Date:  1981-06-13     Revised Date:  2008-11-21    
Medline Journal Info:
Nlm Unique ID:  0417625     Medline TA:  Cell Tissue Res     Country:  GERMANY, WEST    
Other Details:
Languages:  eng     Pagination:  607-23     Citation Subset:  IM    
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MeSH Terms
Diptera / ultrastructure*
Eye / ultrastructure
Microscopy, Electron
Microvilli / ultrastructure
Mitochondria / ultrastructure
Photoreceptor Cells / ultrastructure

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine

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