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6. Molecular basis for the photoreception of a primitive animal, box jellyfish
Abstracts opsin genes of jumping spiders and suggested that two of them form visible pigments and the other forms a UV pigment, based on phylogenetic classifications and comparisons of a key amino acid residue. In this study, we constructed polyclonal antibodies against each jumping spider opsin with mice and rabbits and conducted immunohistochemical analyses of the distribution of opsins in the retina with double staining technique, to elucidate the molecular basis of the color vision of jumping spiders. The results indicated that three kinds of opsins were exclusively expressed in all retinal photoreceptor cells which were visualized with anti-Gq antibody, suggesting that these opsins achieve the color vision in jumping spiders. doi:10.1016/j.cbpb.2007.07.042
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characteristics of photopigment, such as the lysine residue for binding a retinal chromophore in seventh transmembrane region. Phylogenetic analyses of the opsin family indicated that the box jellyfish opsin, together with hydra opsins formed a novel opsin subfamily, suggesting that the box jellyfish opsin has undefined characteristics in opsins of triploblastic animals. doi:10.1016/j.cbpb.2007.07.044
7. Sensitization to water-soluble sodium acetate in the nematode Caenorhabditis elegans Tetsuya Matsuura, Takayuki Oda, Genta Hayashi, Daisuke Sugisaki, Mitsuyuki Ichinose, Dept. Welfare Eng., Fac. Eng., Iwate Univ., Morioka 020-8551, Japan
5. Comparative biochemical analysis of invertebrate visual pigments and melanopsin Akihisa Terakita a, Hisao Tsukamoto a, Mitsumasa Koyanagi a, Michio Sugahara b, Takahiro Yamashita c, Yoshinori Shichida c, a Dept. Biol. and Geosci. Grad. Sch. of Sci. Osaka City Univ., Osaka, 558-8585, Japan; b Inst. Japanese Honeybee, Osaka, 570-0008, Japan; c Dept. of Biophys., Grad. Sch. of Sci., Kyoto Univ., Kyoto, 606-8502, Japan
Melanopsin is a non-visual photopigment found in the deuterostomes. In mammals, it is localized in photosensitive retinal ganglion cells and involved in the circadian photoentrainment and pupillary response. It is phylogenetically close to the visual pigments of invertebrates such as insects and cephalopods. We recently suggested that melanopsin is a bistable pigment and drives a Gq-mediated signal transduction cascade, like the invertebrate visual pigments (Koyanagi et al., Curr. Biol. 15, 1065–1069, 2005). On the other hand, electrophysiological properties are somewhat different between the visual cells and the photosensitive retinal ganglion cells. We here comparatively investigated Gq activation abilities of melanopsin and invertebrate visual pigments. We heterologously expressed the melanopsin from amphioxus in mammalian cell lines and purified it by an affinity chromatography. G protein activation was measured with the purified pigments and purified Gq. The melanopsin and the invertebrate visual pigments activated Gq in light-dependent manner and the activation profiles of them were almost identical. The result suggested that the Gq-activation abilities of the melanopsin and the invertebrate visual pigments are similar.
Continuous presentation of olfactory stimulus causes a decline in the chemotactic response in the nematode Caenorhabditis elegans. In the present study, we revealed an increase in the chemotactic response to water-soluble sodium acetate (NA) of wild type nematodes (N2) when they were preexposed to NA. The chemotaxis index for 1.0 M NA of control worms was approximately 0.7, whereas that for NA of worms, which were preexposed to 1.0 M NA for 90 min in training plate, was approximately 0.9 (p b 0.05). len-1 mutants that had defect in associative learning to water-soluble attractants showed almost the same results as that of N2, suggesting that the increase in the index for NA of preexposed nematodes caused by sensitization to NA, but not associative learning. On the other hand, cat-1 and cat-4 mutants, which were defective in secretion of serotonin and dopamine, did not observed the sensitization to NA. Even if cat-1 and cat-4 mutants were preexposed to NA with various concentration of serotonin during preexposure period, there was no significant difference in the response to NA between control and preexposed mutants. These results suggest a possibility that the sensitization to NA is concerned with secretion of dopamine rather than serotonin. doi:10.1016/j.cbpb.2007.07.045
8. Non-visual photoreceptive function of simple photoreceptors in the ganglion of Onchidium: I. Pulmo-breathing movement Tsukasa Gotow a, Takako Nishi b, a Lab. Neuroanat., Dept. Neurol., Kagoshima Univ. Grad. Sch. Med.-Den. Sci., Kagoshima 890-8520, Japan; b Lab. Physiol., Inst. Natl. Sci., Senshu Univ., Kawasaki 214-8580, Japan
doi:10.1016/j.cbpb.2007.07.043
6. Molecular basis for the photoreception of a primitive animal, box jellyfish Mitsumasa Koyanagi a, Kousuke Takano a,b, Fumio Tokunaga b, Kozo Otsu c, Akihisa Terakita a, a Dept. Biol. and Geosci., Grad. Sch. Sci., Osaka City Univ., Osaka, 558-8585, Japan; b Dept. Earth and Space Sci., Grad. Sch. Sci., Osaka Univ., Toyonaka 560-0043, Japan; c Oki Marine Biol. Stat., Dept. Biol. Sci., Shimane Univ., Oki 685-0024, Japan
Opsins are photoreceptor proteins which underlie various physiologies such as vision and circadian photoentrainment in most animals. Although the molecular basis for photoreceptions of triploblastic animals is well investigated, that of diploblastic animals, such as cnidarians and ctenophores is largely unknown. Interestingly, cnidarian box jellyfish has advanced eyes with corneal lens which are considered to be evolved independently with vertebrate and molluscan lens eyes. We tried to isolate the opsin gene from the box jellyfish to investigate the molecular basis for the photoreception of the advanced eyes of the primitive animal and to understand the diversity of the photoreceptive system throughout the animal kingdom. We cloned one opsin gene, which exhibited all
Simple photoreceptors without microvilli and/or cilia, the photoresponsive neurons, designated as A-P-1, Es-1, Ip-2, and Ip-1, exist in the abdominal ganglion of sea slug Onchidium. Of these, A-P-1 and Es-1 respond to light with a depolarizing receptor potential, whereas Ip-2 and Ip-1 are hyperpolarized by light. These photoreceptors as well as vertebrate simple photoreceptors, called ipRGCs, reach their peak responses 20 to 30 s after the stimulus onset, contrasting with the fast and adaptive response of a few ms in conventional eye photoreceptors (rod/cone). In addition, both types of simple photoreceptors are not only first-order sensory cells, but are also second-order interneurons. These characteristics suggested that simple photoreceptors function as a new photosensory modality, the non-visual photoreceptive system, which codes ambient light intensities, but not as a usual pattern vision system involved in the eye photoreceptors. The cell bodies and their axonal branching patterns of Ip-2 and Ip-1 were visualized by an intracellular staining of Ni2+–rubeanic acid complex. These axonal branching patterns were confirmed by simultaneous recordings of the orthodromic conduction of action potentials triggered by the somatic spikes of Ip-2 and Ip-1 cells. Finally, the present study suggested that Ip2 and Ip-1 cells operate as interneurons/motoneurons innervating a pneumostome related to a pulmo-breathing movement. doi:10.1016/j.cbpb.2007.07.046
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characteristics of photopigment, such as the lysine residue for binding a retinal chromophore in seventh transmembrane region. Phylogenetic analyses of the opsin family indicated that the box jellyfish opsin, together with hydra opsins formed a novel opsin subfamily, suggesting that the box jellyfish opsin has undefined characteristics in opsins of triploblastic animals. doi:10.1016/j.cbpb.2007.07.044
7. Sensitization to water-soluble sodium acetate in the nematode Caenorhabditis elegans Tetsuya Matsuura, Takayuki Oda, Genta Hayashi, Daisuke Sugisaki, Mitsuyuki Ichinose, Dept. Welfare Eng., Fac. Eng., Iwate Univ., Morioka 020-8551, Japan
5. Comparative biochemical analysis of invertebrate visual pigments and melanopsin Akihisa Terakita a, Hisao Tsukamoto a, Mitsumasa Koyanagi a, Michio Sugahara b, Takahiro Yamashita c, Yoshinori Shichida c, a Dept. Biol. and Geosci. Grad. Sch. of Sci. Osaka City Univ., Osaka, 558-8585, Japan; b Inst. Japanese Honeybee, Osaka, 570-0008, Japan; c Dept. of Biophys., Grad. Sch. of Sci., Kyoto Univ., Kyoto, 606-8502, Japan
Melanopsin is a non-visual photopigment found in the deuterostomes. In mammals, it is localized in photosensitive retinal ganglion cells and involved in the circadian photoentrainment and pupillary response. It is phylogenetically close to the visual pigments of invertebrates such as insects and cephalopods. We recently suggested that melanopsin is a bistable pigment and drives a Gq-mediated signal transduction cascade, like the invertebrate visual pigments (Koyanagi et al., Curr. Biol. 15, 1065–1069, 2005). On the other hand, electrophysiological properties are somewhat different between the visual cells and the photosensitive retinal ganglion cells. We here comparatively investigated Gq activation abilities of melanopsin and invertebrate visual pigments. We heterologously expressed the melanopsin from amphioxus in mammalian cell lines and purified it by an affinity chromatography. G protein activation was measured with the purified pigments and purified Gq. The melanopsin and the invertebrate visual pigments activated Gq in light-dependent manner and the activation profiles of them were almost identical. The result suggested that the Gq-activation abilities of the melanopsin and the invertebrate visual pigments are similar.
Continuous presentation of olfactory stimulus causes a decline in the chemotactic response in the nematode Caenorhabditis elegans. In the present study, we revealed an increase in the chemotactic response to water-soluble sodium acetate (NA) of wild type nematodes (N2) when they were preexposed to NA. The chemotaxis index for 1.0 M NA of control worms was approximately 0.7, whereas that for NA of worms, which were preexposed to 1.0 M NA for 90 min in training plate, was approximately 0.9 (p b 0.05). len-1 mutants that had defect in associative learning to water-soluble attractants showed almost the same results as that of N2, suggesting that the increase in the index for NA of preexposed nematodes caused by sensitization to NA, but not associative learning. On the other hand, cat-1 and cat-4 mutants, which were defective in secretion of serotonin and dopamine, did not observed the sensitization to NA. Even if cat-1 and cat-4 mutants were preexposed to NA with various concentration of serotonin during preexposure period, there was no significant difference in the response to NA between control and preexposed mutants. These results suggest a possibility that the sensitization to NA is concerned with secretion of dopamine rather than serotonin. doi:10.1016/j.cbpb.2007.07.045
8. Non-visual photoreceptive function of simple photoreceptors in the ganglion of Onchidium: I. Pulmo-breathing movement Tsukasa Gotow a, Takako Nishi b, a Lab. Neuroanat., Dept. Neurol., Kagoshima Univ. Grad. Sch. Med.-Den. Sci., Kagoshima 890-8520, Japan; b Lab. Physiol., Inst. Natl. Sci., Senshu Univ., Kawasaki 214-8580, Japan
doi:10.1016/j.cbpb.2007.07.043
6. Molecular basis for the photoreception of a primitive animal, box jellyfish Mitsumasa Koyanagi a, Kousuke Takano a,b, Fumio Tokunaga b, Kozo Otsu c, Akihisa Terakita a, a Dept. Biol. and Geosci., Grad. Sch. Sci., Osaka City Univ., Osaka, 558-8585, Japan; b Dept. Earth and Space Sci., Grad. Sch. Sci., Osaka Univ., Toyonaka 560-0043, Japan; c Oki Marine Biol. Stat., Dept. Biol. Sci., Shimane Univ., Oki 685-0024, Japan
Opsins are photoreceptor proteins which underlie various physiologies such as vision and circadian photoentrainment in most animals. Although the molecular basis for photoreceptions of triploblastic animals is well investigated, that of diploblastic animals, such as cnidarians and ctenophores is largely unknown. Interestingly, cnidarian box jellyfish has advanced eyes with corneal lens which are considered to be evolved independently with vertebrate and molluscan lens eyes. We tried to isolate the opsin gene from the box jellyfish to investigate the molecular basis for the photoreception of the advanced eyes of the primitive animal and to understand the diversity of the photoreceptive system throughout the animal kingdom. We cloned one opsin gene, which exhibited all
Simple photoreceptors without microvilli and/or cilia, the photoresponsive neurons, designated as A-P-1, Es-1, Ip-2, and Ip-1, exist in the abdominal ganglion of sea slug Onchidium. Of these, A-P-1 and Es-1 respond to light with a depolarizing receptor potential, whereas Ip-2 and Ip-1 are hyperpolarized by light. These photoreceptors as well as vertebrate simple photoreceptors, called ipRGCs, reach their peak responses 20 to 30 s after the stimulus onset, contrasting with the fast and adaptive response of a few ms in conventional eye photoreceptors (rod/cone). In addition, both types of simple photoreceptors are not only first-order sensory cells, but are also second-order interneurons. These characteristics suggested that simple photoreceptors function as a new photosensory modality, the non-visual photoreceptive system, which codes ambient light intensities, but not as a usual pattern vision system involved in the eye photoreceptors. The cell bodies and their axonal branching patterns of Ip-2 and Ip-1 were visualized by an intracellular staining of Ni2+–rubeanic acid complex. These axonal branching patterns were confirmed by simultaneous recordings of the orthodromic conduction of action potentials triggered by the somatic spikes of Ip-2 and Ip-1 cells. Finally, the present study suggested that Ip2 and Ip-1 cells operate as interneurons/motoneurons innervating a pneumostome related to a pulmo-breathing movement. doi:10.1016/j.cbpb.2007.07.046