Visualization of Retinal Proteins in the Cerebral Ganglion of Ascidian, Halocynthia roretzi

Ohkuma, Mahito; Tsuda, Motoyuki

doi:10.2108/zsj.17.161

Cited by 20 publications

(17 citation statements)

References 36 publications

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“…It was shown that the action spectrum of larval photic behaviour was similar to the absorption spectrum of human rhodopsin (Nakagawa et al, 1999;Tsuda et al, 2001). The presence of rhodopsin in the ocellus was shown by a retinal protein imaging method (Ohkuma and Tsuda, 2000). Three opsins of Ciona intestinalis have been cloned and expression patterns in larvae detected by whole-mount in situ hybridization.…”

Section: Discussionmentioning

confidence: 99%

Direct evidence for the role of pigment cells in the brain of ascidian larvae by laser ablation

Tsuda¹,

Sakurai²,

Goda³

2003

Journal of Experimental Biology

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118

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SUMMARY The anterior sensory vesicle of ascidian larvae contains a single large vesicle in which lie two distinct types of pigment cells, anterior and posterior. The ultrastructure of these pigment cells suggests that the anterior pigment cell is an otolith, presumably used for gravity detection,and the posterior pigment cell is an ocellus, used for photoreception. However, there is no direct experimental evidence for this assignment of function. Upward swimming behaviour occurring during the initial period of larval life was examined before and after laser ablation of the anterior pigment and posterior pigment cells. Posterior pigment cell-ablated larvae retained the upward swimming behaviour, but anterior pigment cell-ablated larvae lost it. These results suggest that the anterior pigment acts as a gravity sensor. The negatively phototactic swimming during the latter part of larval life was also examined before and after laser ablation of the anterior pigment or posterior pigment cells. Anterior pigment cell-ablated larvae retained the phototactic response, but posterior pigment cell-ablated larvae lost it. These results suggest that the posterior pigment of the sensory vesicle is involved in the negatively phototactic, downward swimming behavior. The effect of pressure on swimming behaviour was studied, and a putative pressure-detection organ was found not to be involved in the larval swimming behaviour. These are the first published experimental results that permit a functional role in ascidian larval behavior to be assigned to the sensory organs.

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Section: Discussionmentioning

confidence: 99%

Direct evidence for the role of pigment cells in the brain of ascidian larvae by laser ablation

Tsuda¹,

Sakurai²,

Goda³

2003

Journal of Experimental Biology

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118

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“…Histochemical methods have been applied to the localization of retinal protein in the ascidian tadpole. The retinal protein is reduced to N-retinyl opsin and the localization of N-retinyl opsin in the larva visualized by the time-resolved difference fluorescence imaging method (Ohkuma and Tsuda, 2000). Fluorescence due to the N-retinyl protein is localized at the posterior wall of the sensory vesicle, that is, to the ocellus.…”

Section: Photic Behavior Of Ascidian Larvaementioning

confidence: 99%

“…On the basis of the similarities between the action spectrum of photic larval behavior and Dartnall's nomogram for rhodopsin (Dartnall, 1953), we proposed a "retinal pigment" as the functional photopigment in the ocellus of the ascidian larva. Further evidence for a retinal photoreceptor pigment in the ocellus of the ascidian larva has subsequently been obtained by a retinal protein fluorescence imaging method (Ohkuma and Tsuda, 2000) and by cDNA cloning (Kusakabe et al ., 2001).…”

Section: Introductionmentioning

confidence: 99%

Sensitization and Habituation of the Swimming Behavior in Ascidian Larvae to Light

2003

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Ascidian larvae of Ciona intestinalis change their photic behavior during the course of development. Newly hatched larvae show no response to a light stimulus at any intensity. At 4 hr after hatching, larvae were induced to start to swimming upon the cessation of illumination, and to stop swimming upon the onset of illumination. At a weaker light intensity (5.0 x 10(-3) J/m (2).s), the larvae showed similar responses to either a single stimulus or repeated stimuli of onset and cessation of light until 10 hr after hatching. At a stronger light intensity (3.2 x 10(-1) J/m(2).s), when the stimulus was repeated, they showed sensitization and habituation of the swimming response. At 3 hr after hatching the larvae failed to show any response to an initial stimulus at any intensity of light, but after several repeated stimuli (sensitization) they showed a swimming response at light intensities above 4.0 x 10(-2) J/m (2).s. At 5 hr and with intensity above 1.0 x 10 (-2) J/m(2).s, the larvae showed photoresponses to the first stimulus, but after several repetitions the larvae failed to stop swimming upon the onset of light (habituation). A repeated series of stimuli at stronger intensities of light caused greater habituation; this habituation was retained for about 1 min. Since the larval central nervous system in Ciona is comprised of only about 100 neurons, learning behavior in ascidian larvae should provide insights for a minimal mechanism of memory in vertebrates.

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“…The ascidian, a primitive chordate, is an ideal animal to study the molecular mechanism of the biological clocks for reproduction, because there are three types of Halocynthia roretzi which show different spawning seasons and spawning times . Recently, retina1 proteins in the cerebral ganglion of an ascidian, Halocynthia roretzi, were visua1ized and their 10calization was determined by the retinal protein imaging method (Ohkuma and Tsuda 2000). An enchephalic 131 132 photoreceptor has been found in the deep part of the brain and a retinal protein in the hypothalamus is essential for seasonal reproduction (Y oshikawa and Oishi 1998).…”

Section: Introductionmentioning

confidence: 99%

The Biology of Ascidians

Sawada¹,

Yokosawa²,

Lambert³

2001

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Visualization of Retinal Proteins in the Cerebral Ganglion of Ascidian, Halocynthia roretzi

Cited by 20 publications

References 36 publications

Direct evidence for the role of pigment cells in the brain of ascidian larvae by laser ablation

Direct evidence for the role of pigment cells in the brain of ascidian larvae by laser ablation

Sensitization and Habituation of the Swimming Behavior in Ascidian Larvae to Light

The Biology of Ascidians

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