Cytoplasmic Characteristics of Three Different Rhabdomeric Photoreceptor Cells in a Marine Gastropod, <italic>Onchidium verruculatum</italic>

AbstractCiliary and rhabdomeric photoreceptor cells represent two main lines of photoreceptor evolution in animals. The two photoreceptor-cell types coexist in some animals, however how they functionally integrate is unknown. We used connectomics to map synaptic paths between ciliary and rhabdomeric photoreceptors in the planktonic larva of the annelid Platynereis and found that ciliary photoreceptors are presynaptic to the rhabdomeric circuit. The behaviors mediated by the ciliary and rhabdomeric cells also interact hierarchically. The ciliary photoreceptors are UV-sensitive and mediate downward swimming to non-directional UV light, a behavior absent in ciliary-opsin knockouts. UV avoidance antagonizes positive phototaxis mediated by the rhabdomeric eyes so that vertical swimming direction is determined by the ratio of blue/UV light. Since this ratio increases with depth, Platynereis larvae may use it as a depth gauge during planktonic migration. Our results revealed a functional integration of ciliary and rhabdomeric photoreceptors with implications for eye and photoreceptor evolution.

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Reconstructing the eyes of Urbilateria

Philosophical Transactions of the Royal Society B Biological Sciences ◽

10.1098/rstb.2001.0971 ◽

2001 ◽

Vol 356 (1414) ◽

pp. 1545-1563 ◽

Cited By ~ 120

Author(s):

Detlev Arendt ◽

Joachim Wittbrodt

Keyword(s):

Photoreceptor Cell ◽

Molecular Level ◽

Pigment Cell ◽

Photoreceptor Cells ◽

Cell Types ◽

Rhabdomeric Photoreceptor ◽

Left And Right ◽

The Common ◽

Shared Roles ◽

Rhabdomeric Photoreceptor Cells

The shared roles of Pax6 and Six homologues in the eye development of various bilaterians suggest that Urbilateria, the common ancestors of all Bilateria, already possessed some simple form of eyes. Here, we re–address the homology of bilaterian cerebral eyes at the level of eye anatomy, of eye–constituting cell types and of phototransductory molecules. The most widespread eye type found in Bilateria are the larval pigment–cup eyes located to the left and right of the apical organ in primary, ciliary larvae of Protostomia and Deuterostomia. They can be as simple as comprising a single pigment cell and a single photoreceptor cell in inverse orientation. Another more elaborate type of cerebral pigment–cup eyes with an everse arrangement of photoreceptor cells is found in adult Protostomia. Both inverse larval and everse adult eyes employ rhabdomeric photoreceptor cells and thus differ from the chordate cerebral eyes with ciliary photoreceptors. This is highly significant because on the molecular level we find that for phototransduction rhabdomeric versus ciliary photoreceptor cells employ divergent rhodopsins and non–orthologous G–proteins, rhodopsin kinases and arrestins. Our comparison supports homology of cerebral eyes in Protostomia; it challenges, however, homology of chordate and non–chordate cerebral eyes that employ photoreceptor cells with non–orthologous phototransductory cascades.

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Ciliary and rhabdomeric photoreceptor-cell circuits form a spectral depth gauge in marine zooplankton

eLife ◽

10.7554/elife.36440 ◽

2018 ◽

Vol 7 ◽

Cited By ~ 11

Author(s):

Csaba Verasztó ◽

Martin Gühmann ◽

Huiyong Jia ◽

Vinoth Babu Veedin Rajan ◽

Luis A Bezares-Calderón ◽

...

Keyword(s):

Photoreceptor Cell ◽

Uv Light ◽

Functional Integration ◽

Photoreceptor Cells ◽

Cell Types ◽

Planktonic Larva ◽

Marine Zooplankton ◽

Rhabdomeric Photoreceptor ◽

Depth Gauge ◽

Rhabdomeric Photoreceptor Cells

Ciliary and rhabdomeric photoreceptor cells represent two main lines of photoreceptor-cell evolution in animals. The two cell types coexist in some animals, however how these cells functionally integrate is unknown. We used connectomics to map synaptic paths between ciliary and rhabdomeric photoreceptors in the planktonic larva of the annelid Platynereis and found that ciliary photoreceptors are presynaptic to the rhabdomeric circuit. The behaviors mediated by the ciliary and rhabdomeric cells also interact hierarchically. The ciliary photoreceptors are UV-sensitive and mediate downward swimming in non-directional UV light, a behavior absent in ciliary-opsin knockout larvae. UV avoidance overrides positive phototaxis mediated by the rhabdomeric eyes such that vertical swimming direction is determined by the ratio of blue/UV light. Since this ratio increases with depth, Platynereis larvae may use it as a depth gauge during vertical migration. Our results revealed a functional integration of ciliary and rhabdomeric photoreceptor cells in a zooplankton larva.

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Spindle shaped bodies in foveolar cones of the baboon retina

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s042482010015678x ◽

1989 ◽

Vol 47 ◽

pp. 960-961

Author(s):

W. Krebs ◽

I. Krebs

Keyword(s):

Cross Sections ◽

Inclusion Bodies ◽

Photoreceptor Cells ◽

Papio Anubis ◽

Retinal Photoreceptor ◽

Age Related ◽

Cone Cells ◽

Membrane Bound ◽

Oriented Parallel ◽

Shaped Inclusion

Various inclusion bodies occur in vertebrate retinal photoreceptor cells. Most of them are membrane bound and associated with phagocytosis or they are age related residual bodies. We found an additional inclusion body in foveal cone cells of the baboon (Papio anubis) retina.The eyes of a 15 year old baboon were fixed by immersion in cacodylate buffered glutaraldehyde (2%)/formaldehyde (2%) as described in detail elsewhere . Pieces of retina from various locations, including the fovea, were embedded in epoxy resin such that radial or tangential sections could be cut.Spindle shaped inclusion bodies were found in the cytoplasm of only foveal cones. They were abundant in the inner segments, close to the external limiting membrane (Fig. 1). But they also occurred in the outer fibers, the perikarya, and the inner fibers (Henle’s fibers) of the cone cells. The bodies were between 0.5 and 2 μm long. Their central diameter was 0.2 to 0. 3 μm. They always were oriented parallel to the long axis of the cone cells. In longitudinal sections (Figs. 2,3) they seemed to have a fibrous skeleton that, in cross sections, turned out to consist of plate-like (Fig.4) and tubular profiles (Fig. 5).

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Differentiation Processes of the Ocellar Retina of the Honeybee (Apis Mellifera L.)

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100159692 ◽

1990 ◽

Vol 48 (3) ◽

pp. 430-431

Author(s):

Maria Anna Pabst

Keyword(s):

Apis Mellifera ◽

Distal Part ◽

Cell Layer ◽

Single Layer ◽

Photoreceptor Cells ◽

Distal Segment ◽

Compound Eyes ◽

Thin Sections ◽

Ultrastructural Studies ◽

Adult Worker

In addition to the compound eyes, honeybees have three dorsal ocelli on the vertex of the head. Each ocellus has about 800 elongated photoreceptor cells. They are paired and the distal segment of each pair bears densely packed microvilli forming together a platelike fused rhabdom. Beneath a common cuticular lens a single layer of corneagenous cells is present.Ultrastructural studies were made of the retina of praepupae, different pupal stages and adult worker bees by thin sections and freeze-etch preparations. In praepupae the ocellar anlage consists of a conical group of epidermal cells that differentiate to photoreceptor cells, glial cells and corneagenous cells. Some photoreceptor cells are already paired and show disarrayed microvilli with circularly ordered filaments inside. In ocelli of 2-day-old pupae, when a retinogenous and a lentinogenous cell layer can be clearly distinguished, cell membranes of the distal part of two photoreceptor cells begin to interdigitate with each other and so start to form the definitive microvilli. At the beginning the microvilli often occupy the whole width of the developing rhabdom (Fig. 1).

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

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100159874 ◽

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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