Developing compound eye in lozenge mutants of Drosophila : lozenge expression in the R7 equivalence group

1997 ◽  
Vol 206 (8) ◽  
pp. 481-493 ◽  
Author(s):  
J. R. Crew ◽  
Philip Batterham ◽  
J. A. Pollock
Keyword(s):  
Compound Eye ◽  
Equivalence Group

scholarly journals Regulation of cone cell formation by Canoe and Ras in the developing Drosophila eye

Development ◽  
1997 ◽  
Vol 124 (14) ◽  
pp. 2671-2680 ◽  
Author(s):  
T. Matsuo ◽  
K. Takahashi ◽  
S. Kondo ◽  
K. Kaibuchi ◽  
D. Yamamoto
Keyword(s):  
Compound Eye ◽  
Gene Dosage ◽  
Active Form ◽  
Cell Formation ◽  
Dominant Negative ◽  
Negative Regulator ◽  
Pigment Cells ◽  
Equivalence Group ◽  
Cone Cell ◽  
Cone Cells

Cone cells are lens-secreting cells in ommatidia, the unit eyes that compose the compound eye of Drosophila. Each ommatidium contains four cone cells derived from precursor cells of the R7 equivalence group which express the gene sevenless (sev). When a constitutively active form of Ras1 (Ras1V12) is expressed in the R7 equivalence group cells using the sev promoter (sev-Ras1V12), additional cone cells are formed in the ommatidium. Expression of Ras1N17, a dominant negative form of Ras1, results in the formation of 1–3 fewer cone cells than normal in the ommatidium. The effects of Ras1 variants on cone cell formation are modulated by changing the gene dosage at the canoe (cno) locus, which encodes a cytoplasmic protein with Ras-binding activity. An increase or decrease in gene dosage potentiates the sev-Ras1v12 action, leading to marked induction of cone cells. A decrease in cno+ activity also enhances the sev-Ras1N17 action, resulting in a further decrease in the number of cone cells contained in the ommatidium. In the absence of expression of sev-Ras1V12 or sev-Ras1N17, an overdose of wild-type cno (cno+) promotes cone cell formation while a significant reduction in cno+ activity results in the formation of 1–3 fewer cone cells than normal in the ommatidium. We propose that there are two signaling pathways in cone cell development, one for its promotion and the other for its repression, and Cno functions as a negative regulator for both pathways. We also postulate that Cno predominantly acts on a prevailing pathway in a given developmental context, thereby resulting in either an increase or a decrease in the number of cone cells per ommatidium. The extra cone cells resulting from the interplay of Ras1v12 and Cno are generated from a pool of undifferentiated cells that are normally fated to develop into pigment cells or undergo apoptosis.

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.

Fabrication of an insect-like compound-eye SERS substrate with 3D Ag nano-bowls and its application in optical sensor

2021 ◽  
Vol 330 ◽  
pp. 129357
Author(s):  
Ying Li ◽  
Lei Feng ◽  
Jianhua Li ◽  
Xin Li ◽  
Jun Chen ◽  
...  
Keyword(s):  
Optical Sensor ◽  
Compound Eye ◽  
Sers Substrate

scholarly journals Variation in pleiotropic hub gene expression is associated with interspecific differences in head shape and eye size in Drosophila

2021 ◽  
Author(s):  
Elisa Buchberger ◽  
Anıl Bilen ◽  
Sanem Ayaz ◽  
David Salamanca ◽  
Cristina Matas de las Heras ◽  
...  
Keyword(s):  
Natural Variation ◽  
Compound Eye ◽  
Genetic Manipulation ◽  
Morphological Evolution ◽  
Morphological Diversity ◽  
Network Evolution ◽  
Head Shape ◽  
Eye Size ◽  
Recurrent Mutations ◽  
Repeated Evolution

Abstract Revealing the mechanisms underlying the breath-taking morphological diversity observed in nature is a major challenge in Biology. It has been established that recurrent mutations in hotspot genes cause the repeated evolution of morphological traits, such as body pigmentation or the gain and loss of structures. To date, however, it remains elusive whether hotspot genes contribute to natural variation in the size and shape of organs. Since natural variation in head morphology is pervasive in Drosophila, we studied the molecular and developmental basis of differences in compound eye size and head shape in two closely related Drosophila species. We show differences in the progression of retinal differentiation between species and we applied comparative transcriptomics and chromatin accessibility data to identify the GATA transcription factor Pannier (Pnr) as central factor associated with these differences. Although the genetic manipulation of Pnr affected multiple aspects of dorsal head development, the effect of natural variation is restricted to a subset of the phenotypic space. We present data suggesting that this developmental constraint is caused by the co-evolution of expression of pnr and its co-factor u-shaped (ush). We propose that natural variation in expression or function of highly connected developmental regulators with pleiotropic functions is a major driver for morphological evolution and we discuss implications on gene regulatory network evolution. In comparison to previous findings, our data strongly suggests that evolutionary hotspots are not the only contributors to the repeated evolution of eye size and head shape in Drosophila.

scholarly journals Semper's cells in the insect compound eye: Insights into ocular form and function

2021 ◽  
Author(s):  
Mark A. Charlton-Perkins ◽  
Markus Friedrich ◽  
Tiffany A. Cook
Keyword(s):  
Compound Eye ◽  
Form And Function ◽  
And Function

Design and Fabrication of Double-Layer Curved Compound Eye via Two-Photon Polymerization

2021 ◽  
Vol 33 (5) ◽  
pp. 231-234
Author(s):  
Xian Jing ◽  
Kaixuan Wang ◽  
Rongxin Zhu ◽  
Jieqiong Lin ◽  
Baojun Yu ◽  
...  
Keyword(s):  
Double Layer ◽  
Compound Eye ◽  
Two Photon ◽  
Two Photon Polymerization
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