Cell clones and pattern formation: Developmental restrictions in the compound eye ofDrosophila

1978 ◽  
Vol 184 (2) ◽  
pp. 155-170 ◽  
Author(s):  
J. A. Campos-Ortega ◽  
Michael Waitz
Keyword(s):  
Pattern Formation ◽  
Compound Eye ◽  
Cell Clones

Cell clones and pattern formation: Genetic eye mosaics inDrosophila melanogaster

1976 ◽  
Vol 179 (4) ◽  
pp. 275-289 ◽  
Author(s):  
Alois Hofbauer ◽  
J. A. Campos-Ortega
Keyword(s):  
Pattern Formation ◽  
Cell Clones

cell clones and pattern formation: Studies onsevenless, a mutant ofDrosophila melanogaster

1979 ◽  
Vol 186 (1) ◽  
pp. 27-50 ◽  
Author(s):  
J. A. Campos-Ortega ◽  
Gerd J�rgens ◽  
Alois Hofbauer
Keyword(s):  
Pattern Formation ◽  
Cell Clones

Drosophila atonal controls photoreceptor R8-specific properties and modulates both receptor tyrosine kinase and Hedgehog signalling

Development ◽  
2000 ◽  
Vol 127 (8) ◽  
pp. 1681-1689 ◽  
Author(s):  
N.M. White ◽  
A.P. Jarman
Keyword(s):  
Pattern Formation ◽  
Tyrosine Kinase ◽  
Receptor Tyrosine Kinase ◽  
Compound Eye ◽  
Eye Development ◽  
Axon Pathfinding ◽  
Proneural Gene ◽  
Hedgehog Signalling ◽  
Drosophila Eye

During Drosophila eye development, the proneural gene atonal specifies founding R8 photoreceptors of individual ommatidia, evenly spaced relative to one another in a pattern that prefigures ommatidial organisation in the mature compound eye. Beyond providing neural competence, however, it has remained unclear to what extent atonal controls specific R8 properties. We show here that reduced Atonal function gives rise to R8 photoreceptors that are functionally compromised: both recruitment and axon pathfinding defects are evident. Conversely, prolonged Atonal expression in R8 photoreceptors induces defects in inductive recruitment as a consequence of hyperactive EGFR signalling. Surprisingly, such prolonged expression also results in R8 pattern formation defects in a process associated with both Hedgehog and Receptor Tyrosine Kinase signalling. Our results strongly suggest that Atonal regulates signalling and other properties of R8 precursors.

The beginning of pattern formation in the Drosophila compound eye: the morphogenetic furrow and the second mitotic wave

Development ◽  
1991 ◽  
Vol 113 (3) ◽  
pp. 841-850 ◽  
Author(s):  
T. Wolff ◽  
D.F. Ready
Keyword(s):  
Pattern Formation ◽  
Lead Sulfide ◽  
Compound Eye ◽  
Eye Development ◽  
Periodic Pattern ◽  
Cell Analysis ◽  
Morphogenetic Furrow ◽  
Early Stages ◽  
Mitotic Wave ◽  
A Cell

Events in the morphogenetic furrow set the stage for all subsequent compound eye development in Drosophila. The periodic pattern of the adult eye begins in the furrow with the spaced initiation of ommatidial rudiments, the preclusters. A wave of mitosis closely follows the furrow. A cell-by-cell analysis reveals details of these events. Early stages of ommatidial assembly can be resolved using a lead sulfide stain. Overt ommatidial organization begins in the morphogenetic furrow as cells gather into periodically spaced concentric aggregates. A stereotyped sequence of cell rearrangements converts these aggregates into preclusters. In the furrow, new rows of ommatidia are initiated at the equator and grow as new clusters are added to the peripheral ends. Mitotic labeling using BrdU feeds shows that all cells not incorporated into a precluster divide. BrdU injections show that cells divide roughly simultaneously between two adjacent rows of ommatidia.

Computer Reconstruction of the Cellular Architecture of the Daphnia Magna Optic Ganglion

1975 ◽  
Vol 33 ◽  
pp. 284-285
Author(s):  
E. R. Macagno ◽  
C. Levinthal
Keyword(s):  
Daphnia Magna ◽  
Genetic Background ◽  
Compound Eye ◽  
Synaptic Connectivity ◽  
Serial Sections ◽  
Cross Sectional ◽  
Small Crustacean ◽  
Optic Ganglion ◽  
Structural Invariance ◽  
High Degree

The optic ganglion of Daphnia Magna, a small crustacean that reproduces parthenogenetically contains about three hundred neurons: 110 neurons in the Lamina or anterior region and about 190 neurons in the Medulla or posterior region. The ganglion lies in the midplane of the organism and shows a high degree of left-right symmetry in its structures. The Lamina neurons form the first projection of the visual output from 176 retinula cells in the compound eye. In order to answer questions about structural invariance under constant genetic background, we have begun to reconstruct in detail the morphology and synaptic connectivity of various neurons in this ganglion from electron micrographs of serial sections (1). The ganglion is sectioned in a dorso-ventra1 direction so as to minimize the cross-sectional area photographed in each section. This area is about 60 μm x 120 μm, and hence most of the ganglion fit in a single 70 mm micrograph at the lowest magnification (685x) available on our Zeiss EM9-S.

Actin and α-tubulin immuno-EM labelings reveal differences in intra versus interphotoreceptor matrix

1990 ◽  
Vol 48 (3) ◽  
pp. 466-467
Author(s):  
Matti Järvilehto ◽  
Riitta Harjula
Keyword(s):  
Compound Eye ◽  
Frozen Section ◽  
Smooth Muscle Actin ◽  
Photoreceptor Cells ◽  
Immune Serum ◽  
Cell Organelles ◽  
Calliphora Erythrocephala ◽  
Optical Axes ◽  
Interphotoreceptor Matrix ◽  
Similar Kind

The photoreceptor cells in the compound eyes of higher diptera are clustered in groups (ommatidia) of eight receptor cells. The cells from six adjacent ommatidia are organized into optical units, neuro-ommatia sharing the same visual field. In those ommatidia the optical axes of the photopigment containing structures (rhabdomeres) are parallel. The rhabdomeres of the photoreceptor cells are separated from each other by an interstitial i.e innerommatidial space (IOS). In the photoreceptor cell body, besides of the normal cell organelles, a cellular matrix is a structurally apparent component. Similar kind of reticular formation is also found in the IOS containing some unidentified filamentary substance, of which composition and functional significance for optical properties of vision is the aim of this report.The prefixed (2% PA + 0.2% GA in 0.1-n phosphate buffer, pH 7.4, for 1h), frozen section blocks of the compound eye of the blowfly (Calliphora erythrocephala) were prepared by immuno-cryo-techniques. The ultrathin cryosections were incubated with antibodies of monoclonal α-tubulin and polyclonal smooth muscle actin. Control labelings of excess of antigen, non-immune serum and non-present antibody were perforated.

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