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.

Distribution of the myosin I-like ninaC proteins in the Drosophila retina and ultrastructural analysis of mutant phenotypes

1992 ◽  
Vol 101 (1) ◽  
pp. 247-254 ◽  
Author(s):  
J.L. Hicks ◽  
D.S. Williams
Keyword(s):  
Compound Eye ◽  
Photoreceptor Cells ◽  
Amino Acid Sequences ◽  
Ultrastructural Analysis ◽  
Multivesicular Bodies ◽  
Filamentous Actin ◽  
Electron Microscopic ◽  
Myosin I ◽  
Specific Proteins ◽  
Mutant Phenotypes

The Drosophila ninaC gene encodes for two head-specific proteins of 132 kDa and 174 kDa. Their predicted amino acid sequences indicate that they may have myosin I and kinase properties. We have: (1) determined the cellular and subcellular distributions of the ninaC proteins in the Drosophila retina by electron microscopic immunocytochemistry with an antibody specific for epitopes shared by both proteins; (2) characterized the ultrastructure of the mutant phenotype. The proteins were detected only in the photoreceptor cells, but were detected in all classes of the compound eye photoreceptors. Within the photoreceptors, they were found in the rhabdomeral microvilli and the cytoplasm adjacent to the rhabdomeres. This distribution coincides with that shown previously for actin filaments. Immunolabelling of tissue from the ninaC P221 mutant, which lacks the 174 kDa protein, and two mutants whose rhabdomeres degenerate, suggests that the 132 kDa protein is present primarily in the cytoplasm adjacent to the rhabdomeres, and that the 174 kDa protein is concentrated in the rhabdomeres. Our ultrastructural analysis showed that the axial cytoskeleton of the rhabdomeral microvilli (which contains filamentous actin) was absent in both the null and P221 mutants. In the photoreceptor cell cytoplasm, the number of multivesicular bodies in the null mutant, but not the P221 mutant, was 3-fold greater in comparison with wild-type.(ABSTRACT TRUNCATED AT 250 WORDS)

Die Spektralsensitivität von Insekten-Komplexaugen im Ultraviolett bis 290 mμ

1959 ◽  
Vol 14 (4) ◽  
pp. 273-278 ◽  
Author(s):  
Jost Bernhard Walther ◽  
Eberhard Dodt
Keyword(s):  
Ultraviolet Light ◽  
Periplaneta Americana ◽  
Light Adaptation ◽  
Compound Eye ◽  
Monochromatic Light ◽  
High Sensitivity ◽  
Relative Sensitivity ◽  
Calliphora Erythrocephala ◽  
Sensitivity Curves ◽  
Fly Eye

Behaviour experiments have shown that insects react to ultraviolet light. Almost no data are available within this spectral range, however, on the sensitivity of their light sense organs.In this investigation the relative spectral sensitivity (1/Q) of the compound eye of the fly, Calliphora erythrocephala, and various areas of the compound eye of the cockroach, Periplaneta americana, was measured including the ultraviolet range down to 290 mμ. Equal amplitudes of the electroretinogram indicated equal efficiencies of the stimuli.The sensitivity curve in both species shows, besides the known maximum in the blue green, a second maximum in the ultraviolet. This second maximum was found between 341-369 mμ depending on the species and the particular area of the eye. At still shorter wave lengths sensitivity decreases. In the fly eye and the upper part of the cockroach eye the sensitivity maximum in the ultraviolet is higher than in the bluegreen, whereas in the ventral part of the cockroch eye it is lower. Monochromatic light adaptation selectively influences the relative sensitivity of the upper part of the cockroach eye.The sensitivity curves are discussed with regard to visual pigments and types of receptors. Fluorescence of the eye media is considered to have only negligible if any influence on the high sensitivity for ultraviolet light.

The accuracy of the patterns of connexions of the first- and second-order neurons of the visual system of Calliphora

1970 ◽  
Vol 175 (1038) ◽  
pp. 69-82 ◽  
Keyword(s):  
Single Neuron ◽  
Compound Eye ◽  
Photoreceptor Cells ◽  
Mirror Image ◽  
Second Order ◽  
Visual Axis ◽  
First Order ◽  
Definite Pattern ◽  
Small Bundle ◽  
Do So

The axons of the primary photoreceptor cells of the compound eye of the fly interweave in a complex but definite pattern before they terminate upon the second-order neurons. Of approximately 650 short retinula axons from behind 120 facets of the eye none terminated at an incorrect lamina cartridge. Six, seven, or eight first-order terminals upon one pair of second-order cells are arranged in a rotational sequence that is related to the positions of the retinula cells within the ommatidia. Errors in location of the terminal among its neighbours occurred only ten times. The asymmetry of the receptor pattern in the dorsal half of the eye has a mirror image in the ventral half. Along the equator of the eye is a plane of symmetry which many axons necessarily cross in maintaining the appropriate connexions of their receptors. Axons which cross this plane of symmetry have somehow found their appropriate second-order cells, although to do so they must have grown through a milieu which is the mirror image of that in their own half of the eye. Each pair of second-order axons proceeding from the lamina forms a small bundle with the axons of the two long retinula cells that have the same visual axis. Between the lamina and the medulla is a chiasma (with the crossing in the horizontal plane) through which bundles from the lamina pass to project in exactly reverse order upon the medulla. No errors of projection have been found at the single neuron level in this chiasma.

Cytochemical Localization of Guanylate and Adenylate Cyclase in Photoreceptor Cells of the Fly

1995 ◽  
Vol 50 (9-10) ◽  
pp. 695-698 ◽  
Author(s):  
Ulrich Schraermeyer ◽  
Hennig Stieve ◽  
Michael Rack
Keyword(s):  
Spatial Distribution ◽  
Adenylate Cyclase ◽  
Guanylate Cyclase ◽  
Cyclic Nucleotides ◽  
Photoreceptor Cells ◽  
Cytochemical Localization ◽  
Calliphora Erythrocephala ◽  
Cytochemical Method ◽  
Enzyme Cascade

Abstract In photoreceptor cells of invertebrates light triggers an enzyme cascade in which the phos-phoinositide pathway is crucially involved. Likewise, there is growing evidence of an impor­ tant role of cyclic nucleotides, too. To localize these enzymes able to catalyze the formation of cGM P and cAMP, the spatial distribution of guanylate cyclase (EC 4.6.1.2) and adenylate cyclase (EC 4.6.1.1) was determined in photoreceptor cells of the fly. In photoreceptor cells of the blowfly (Calliphora erythrocephala), the electron dense reaction product of guanylate cyclase was found within the phototransducing region, the rhabdomeral microvilli and in the mitochondria. Staining was also observed throughout the cytoplasm of the microvilli. With the same cytochemical method, reaction product for adenylate cyclase was found on the tips of the photosensory membrane, and not in the cytoplasm of the rhabdomeral microvilli. The results presented here further argue for an important role of one or possibly two cyclic nucleotides in the photoreceptor cells, and possibly in the process of phototransduction of in­ vertebrates.

Mesectodermal Leiomyoma of the Ciliary Body: A Unique Variant of Leiomyoma with Myogenic and Neurogenic Histological Features

2021 ◽  
pp. 106689692110386
Author(s):  
Osamu Inamori ◽  
Hideki Fukuoka ◽  
Michiko Nagamine ◽  
Chie Sotozono ◽  
Eiichi Konishi
Keyword(s):  
Malignant Melanoma ◽  
Ciliary Body ◽  
Benign Tumor ◽  
Frozen Section ◽  
Smooth Muscle Actin ◽  
Japanese Woman ◽  
Reproductive Age ◽  
Positive Staining ◽  
Rare Benign Tumor ◽  
Slow Growing

Mesectodermal leiomyoma of the ciliary body is a rare benign tumor, showing both neurogenic and myogenic characteristics. This tumor typically shows predilection for women of reproductive age. Because it is almost impossible to clinically distinguish this tumor from malignant melanoma, unnecessary eye enucleations have been unfortunately performed. Herein, we report a case of mesectodermal leiomyoma of the ciliary body in a young Japanese woman. She was referred to our hospital due to a slow-growing mass in her left iris. A malignant tumor could not be clinically ruled out and surgery with intraoperative pathology consultation was performed. Intraoperative frozen section diagnosis was a benign tumor with neurogenic features, and a simple excision of the tumor was performed. Histologically, the tumor was composed of diffuse growth of spindle cells with fibrillary indistinctive cytoplasm. Immunohistochemical examination showed diffuse positive staining of α-smooth muscle actin, h-caldesmon, calponin, and CD56. Scattered tumor cells were weakly positive for desmin. Neither melanocytic markers nor neural markers except for CD56 were positive. We diagnosed this tumor as mesectodermal leiomyoma. Mesectodermal leiomyoma is rare and often misdiagnosed as malignant melanoma. To avoid overtreatment, a correct preoperative diagnosis is essential.

scholarly journals Identification of Genes Involved in the Differentiation of R7y and R7p Photoreceptor Cells in Drosophila

2020 ◽  
Vol 10 (11) ◽  
pp. 3949-3958
Author(s):  
James B. Earl ◽  
Lauren A. Vanderlinden ◽  
Thomas L. Jacobsen ◽  
John C. Aldrich ◽  
Laura M. Saba ◽  
...  
Keyword(s):  
Cell Fate ◽  
Protein Modification ◽  
Compound Eye ◽  
Photoreceptor Cells ◽  
Loss Of Function ◽  
Gain Of Function ◽  
Link Type ◽  
Transposon Insertion ◽  
Gtpase Activation ◽  
Yellow Type

The R7 and R8 photoreceptor cells of the Drosophila compound eye mediate color vision. Throughout the majority of the eye, these cells occur in two principal types of ommatidia. Approximately 35% of ommatidia are of the pale type and express Rh3 in R7 cells and Rh5 in R8 cells. The remaining 65% are of the yellow type and express Rh4 in R7 cells and Rh6 in R8 cells. The specification of an R8 cell in a pale or yellow ommatidium depends on the fate of the adjacent R7 cell. However, pale and yellow R7 cells are specified by a stochastic process that requires the genes spineless, tango and klumpfuss. To identify additional genes involved in this process we performed genetic screens using a collection of 480 P{EP} transposon insertion strains. We identified genes in gain of function and loss of function screens that significantly altered the percentage of Rh3 expressing R7 cells (Rh3%) from wild-type. 36 strains resulted in altered Rh3% in the gain of function screen where the P{EP} insertion strains were crossed to a sevEP-GAL4 driver line. 53 strains resulted in altered Rh3% in the heterozygous loss of function screen. 4 strains showed effects that differed between the two screens, suggesting that the effect found in the gain of function screen was either larger than, or potentially masked by, the P{EP} insertion alone. Analyses of homozygotes validated many of the candidates identified. These results suggest that R7 cell fate specification is sensitive to perturbations in mRNA transcription, splicing and localization, growth inhibition, post-translational protein modification, cleavage and secretion, hedgehog signaling, ubiquitin protease activity, GTPase activation, actin and cytoskeletal regulation, and Ser/Thr kinase activity, among other diverse signaling and cell biological processes.

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