| Retinal photoreceptor arrangement, SWS1 and LWS opsin sequence, and electroretinography in the South American marsupial Thylamys elegans (Waterhouse, 1839). | |
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MedLine Citation:
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PMID: 20187149 Owner: NLM Status: MEDLINE |
Abstract/OtherAbstract:
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We studied the retinal photoreceptors in the mouse opossum Thylamys elegans, a nocturnal South American marsupial. A variety of photoreceptor properties and color vision capabilities have been documented in Australian marsupials, and we were interested to establish what similarities and differences this American marsupial showed. Thylamys opsin gene sequencing revealed two cone opsins, a longwave-sensitive (LWS) opsin and a shortwave-sensitive (SWS1) opsin with deduced peak sensitivities at 560 nm and 360 nm (ultraviolet), respectively. Immunocytochemistry located these opsins to separate cone populations, a majority of LWS cones (density range 1,600-5,600/mm(2)) and a minority of SWS1 cones (density range 100-690/mm(2)). With rod densities of 440,000-590,000/mm(2), the cones constituted 0.4-1.2% of the photoreceptors. This is a suitable adaptation to nocturnal vision. Cone densities peaked in a horizontally elongated region ventral to the optic nerve head. In ventral-but not dorsal-retina, roughly 40% of the LWS opsin-expressing cones occurred as close pairs (double cones), and one member of each double cone contained a colorless oil droplet. The corneal electroretinogram (ERG) showed a high scotopic sensitivity with a rod peak sensitivity at 505 nm. At mesopic light levels, the spectral ERG revealed the contributions of a UV-sensitive SWS1 cone mechanism and an LWS cone mechanism with peak sensitivities at 365 nm and 555 nm, respectively, confirming the tuning predictions from the cone opsin sequences. The two spectral cone types provide the basis for dichromatic color vision, or trichromacy if the rods contribute to color processing at mesopic light levels. |
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Authors:
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Adri?n G Palacios; Francisco Bozinovic; Alex Vielma; Catherine A Arrese; David M Hunt; Leo Peichl |
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Publication Detail:
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Type: Journal Article; Research Support, Non-U.S. Gov't |
Journal Detail:
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Title: The Journal of comparative neurology Volume: 518 ISSN: 1096-9861 ISO Abbreviation: J. Comp. Neurol. Publication Date: 2010 May |
Date Detail:
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Created Date: 2010-03-08 Completed Date: 2010-05-17 Revised Date: - |
Medline Journal Info:
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Nlm Unique ID: 0406041 Medline TA: J Comp Neurol Country: United States |
Other Details:
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Languages: eng Pagination: 1589-602 Citation Subset: IM |
Copyright Information:
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(c) 2009 Wiley-Liss, Inc. |
Affiliation:
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Centro de Neurociencia de Valpara?so, Facultad de Ciencias, Universidad de Valpara?so, Valpara?so 2370006, Chile. |
Export Citation:
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APA/MLA Format Download EndNote Download BibTex |
| MeSH Terms | |
Descriptor/Qualifier:
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Amino Acid Sequence Animals Electroretinography Eye / anatomy & histology Light Male Molecular Sequence Data Opossums* / anatomy & histology, physiology Opsins* / classification, genetics, metabolism Photoreceptor Cells, Vertebrate* / cytology, metabolism Phylogeny Sequence Alignment |
| Chemical | |
Reg. No./Substance:
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0/Opsins |
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