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  • 1
    Electronic Resource
    Electronic Resource
    [s.l.] : Nature Publishing Group
    Nature structural & molecular biology 11 (2004), S. 284-289 
    ISSN: 1545-9985
    Source: Nature Archives 1869 - 2009
    Topics: Biology , Medicine
    Notes: [Auszug] The counterion, a negatively charged amino acid residue that stabilizes a positive charge on the retinylidene chromophore, is essential for rhodopsin to receive visible light. The counterion in vertebrate rhodopsins, Glu113 in the third transmembrane helix, has an additional role as an ...
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Amsterdam : Elsevier
    FEBS Letters 330 (1993), S. 197-200 
    ISSN: 0014-5793
    Keywords: Crayfish ; G-protein ; Gq ; Phospholipase C ; Photoreceptor membrane ; Procambarus clarkii ; Rhodopsin ; Signal transduction
    Source: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics: Biology , Chemistry and Pharmacology , Physics
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    Amsterdam : Elsevier
    ISSN: 0305-0491
    Source: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics: Biology , Chemistry and Pharmacology
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    Springer
    Journal of comparative physiology 173 (1993), S. 615-619 
    ISSN: 1432-1351
    Keywords: Photoreception ; Circadian rhythms ; Visual pigment ; Antarctica ; Crustacea
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract 1. Relative retinal amounts in the compound eye of the Antarctic amphipod Orchomene plebs were assessed during conditions of continuous summer daylight every 3 h over a period of 48 h. The habitat of the experimental animal is the bottom of the Ross Sea (78°S; 166°E) down to depths of at least 400 m; water temperature is a constant — 1.8° C. A periodicity of 12 h was detected with relative amounts of 11-cis retinal exhibiting peaks at midday and at midnight and troughs at 7.00 h and 19.00 h. 2. The result that 90% of retinoid were insoluble in n-hexane suggests that at least 90% of the measured retinoid were attached to membrane-bound proteins such as opsin. 3. Selective light adaptation showed that the visual pigments were thermostable and photoregenerable. The main absorbance peak of rhodopsin, compared with metarhodopsin, seems to be in the longer wavelengths.
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    Springer
    Journal of comparative physiology 183 (1998), S. 165-170 
    ISSN: 1432-1351
    Keywords: Key words Firefly ; Chromophore ; Retinal ; 3-Hydroxyretinal ; Ultraviolet receptor
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract Based on electroretinogram measurements, fireflies are reported to possess two spectral-sensitivity peaks: one in the near-ultraviolet and the other in the green region. This suggests that at least two kinds of visual pigment should be present (Lall and Lloyd 1989). Analyses by high pressure liquid chromatography revealed that there are two kinds of chromophores, i.e., retinal (A1) and 3-hydroxyretinal (A3), in the compound eye of Japanese fireflies of the genus Luciola (Gleadall et␣al. 1989). Through selective light-adaptation experiments and in vitro analyses by high pressure liquid chromatography, it is demonstrated that the A1 is the chromophore of an ultraviolet-sensitive visual pigment and the A3 is the chromophore of a green-sensitive pigment. The absolute amounts of A1 and A3 were, respectively, 32.1 ± 3.9 and 111.1 ± 35.2 pmol in male, and 26.9 ± 6.9 and 63.4 ± 18.2 pmol in female (mean ± SD per animal). These results indicate that the amount of green-sensitive visual pigment in males is significantly higher than in females. A difference in the distribution of these chromophores is demonstrated in the eyes of female (but not male) fireflies: in the dorsal region of the female eye, the A1:A3 ratio is higher than that for the rest of the eye.
    Type of Medium: Electronic Resource
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  • 6
    Electronic Resource
    Electronic Resource
    Springer
    Journal of comparative physiology 183 (1998), S. 411-417 
    ISSN: 1432-1351
    Keywords: Key words Photoreceptor cell ; Rhabdom ; β subunit of Gq ; Phototransduction ; Crayfish
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract In crayfish photoreceptor cells, Gq-type G-protein plays a central role in the phototransduction pathway, and the translocation of Gqα has been proposed as one of the molecular mechanisms to control photoreceptor sensitivity. We here investigated β subunit of Gq and its localization profiles under various light conditions in the crayfish photoreceptor cells to understand the functional characteristic of visual Gq in the phototransduction pathway. An immunoprecipitation experiment was performed using an anti-Gqα antibody and a thiol-cleavable crosslinker. A 39 kDa protein was co-immunoprecipitated with Gqα, but not by irradiation, in the presence of GTPγS. The partial amino acid sequence of the 39 kDa protein was similar to Gβe in Drosophila photoreceptors, indicating that the crayfish Gβ which combines with Gqα is a Gβe homologue. Immunohistochemical and immunoblot analyses revealed that the amount of the Gβ decreased in the rhabdomeric membranes and increased in the cytoplasm in the light, compared with that in the dark. The profile of the translocation was similar to that reported for Gqα. Since both α and βγ subunits are necessary for G-proteins to be activated by rhodopsin in the rhabdom, the light-modulated translocation of a Gβe homologue possibly controls the amount of Gq which can be activated by light-stimulated rhodopsin.
    Type of Medium: Electronic Resource
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  • 7
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Science Ltd
    Journal of neurochemistry 91 (2004), S. 0 
    ISSN: 1471-4159
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: G protein-coupled receptors have a common structural motif of seven transmembrane α-helices and are classified into different families showing no sequence similarity. Extensive studies have been conducted on the structure–function relationship in family 1 receptors, but those in other families have not been well studied. In this study, to investigate the molecular basis leading to the G protein activation by metabotropic glutamate receptor (mGluR), the member of family 3, we searched for the amino acid residues responsible for the G protein activation in the second cytoplasmic loop, which was thought to be the main G protein binding region. Analyses of the systematical mutations of Gi/Go-coupled mGluR8 revealed the presence of a constitutively active mutation in the C-terminal region of the second loop. The corresponding mutation in the second loop of Gq-coupled mGluR1 also exhibited high agonist-independent activity. These results indicate that there is a common constitutive active mutation site regardless of mGluR subtypes, suggesting that the structural change of the junction between the second cytoplasmic loop and helix IV is strongly linked to the formation of the active state.
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  • 8
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    BioMed Central
    Publication Date: 2015-09-17
    Description: Background: Recent genome projects of various animals have uncovered an unexpectedly large number of opsin genes, which encode protein moieties of photoreceptor molecules, in most animals. In visual systems, the biological meanings of this diversification are clear; multiple types of visual opsins with different spectral sensitivities are responsible for color vision. However, the significance of the diversification of non-visual opsins remains uncertain, in spite of the importance of understanding the molecular mechanism and evolution of varied non-visual photoreceptions. Results: Here, we investigated the diversification of the pineal photopigment parapinopsin, which serves as the UV-sensitive photopigment for the pineal wavelength discrimination in the lamprey, linking it with other pineal photoreception. Spectroscopic analyses of the recombinant pigments of the two teleost parapinopsins PP1 and PP2 revealed that PP1 is a UV-sensitive pigment, similar to lamprey parapinopsin, but PP2 is a blue-sensitive pigment, with an absorption maximum at 460–480 nm, showing the diversification of non-visual pigment with respect to spectral sensitivity. We also found that PP1 and PP2 exhibit mutually exclusive expressions in the pineal organs of three teleost species. By using transgenic zebrafish in which these parapinopsin-expressing cells are labeled, we found that PP1-expressing cells basically possess neuronal processes, which is consistent with their involvement in wavelength discrimination. Interestingly, however, PP2-expressing cells rarely possess neuronal processes, raising the possibility that PP2 could be involved in non-neural responses rather than neural responses. Furthermore, we found that PP2-expressing cells contain serotonin and aanat2, the key enzyme involved in melatonin synthesis from serotonin, whereas PP1-expressing cells do not contain either, suggesting that blue-sensitive PP2 is instead involved in light-regulation of melatonin secretion. Conclusions: In this paper, we have clearly shown the different molecular properties of duplicated non-visual opsins by demonstrating the diversification of parapinopsin with respect to spectral sensitivity. Moreover, we have shown a plausible link between the diversification and its physiological impact by discovering a strong candidate for the underlying pigment in light-regulated melatonin secretion in zebrafish; the diversification could generate a new contribution of parapinopsin to pineal photoreception. Current findings could also provide an opportunity to understand the “color” preference of non-visual photoreception.
    Electronic ISSN: 1741-7007
    Topics: Biology
    Published by BioMed Central
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  • 9
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    American Association for the Advancement of Science (AAAS)
    Publication Date: 2012-01-28
    Description: The principal eyes of jumping spiders have a unique retina with four tiered photoreceptor layers, on each of which light of different wavelengths is focused by a lens with appreciable chromatic aberration. We found that all photoreceptors in both the deepest and second-deepest layers contain a green-sensitive visual pigment, although green light is only focused on the deepest layer. This mismatch indicates that the second-deepest layer always receives defocused images, which contain depth information of the scene in optical theory. Behavioral experiments revealed that depth perception in the spider was affected by the wavelength of the illuminating light, which affects the amount of defocus in the images resulting from chromatic aberration. Therefore, we propose a depth perception mechanism based on how much the retinal image is defocused.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Nagata, Takashi -- Koyanagi, Mitsumasa -- Tsukamoto, Hisao -- Saeki, Shinjiro -- Isono, Kunio -- Shichida, Yoshinori -- Tokunaga, Fumio -- Kinoshita, Michiyo -- Arikawa, Kentaro -- Terakita, Akihisa -- New York, N.Y. -- Science. 2012 Jan 27;335(6067):469-71. doi: 10.1126/science.1211667.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Biology and Geosciences, Graduate School of Science, Osaka City University, Osaka, Japan.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/22282813" target="_blank"〉PubMed〈/a〉
    Keywords: Animals ; Cues ; Depth Perception ; Fixation, Ocular ; Light ; Locomotion ; Opsins/analysis/physiology ; Photoreceptor Cells, Invertebrate/chemistry/*physiology ; Predatory Behavior ; Spiders/*physiology ; Vision, Ocular
    Print ISSN: 0036-8075
    Electronic ISSN: 1095-9203
    Topics: Biology , Chemistry and Pharmacology , Computer Science , Medicine , Natural Sciences in General , Physics
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