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Jenkinson E, Alexander AJ, Camp PJ. Measurements of large optical rotary dispersion in the adipose eyelid of Atlantic mackerel ( Scomber scombrus). J R Soc Interface 2023; 20:20230025. [PMID: 37015263 PMCID: PMC10072936 DOI: 10.1098/rsif.2023.0025] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/06/2023] Open
Abstract
Collagen is the most prevalent of Nature's structural proteins, and is found in the extracellular matrices of animals. The structures of collagen molecules and aggregates are chiral, which leads to the rotation of transmitted, plane-polarized light. Here, it is shown that the concentrations of chiral molecules and aggregates in the optically transparent, adipose eyelid of Atlantic mackerel (Scomber scombrus) can be so high, that plane-polarized light in the visible spectrum is rotated by tens to hundreds of degrees, depending on wavelength (the optical rotatory dispersion (ORD)). This gives rise to intensely coloured images of eyelid samples when illuminated with white light and viewed between crossed polarizers. The ORD in the visible spectrum is measured with monochromatic light sources, and using this dispersion, the variation of optical thickness within a sample (proportional to collagen concentration and path length) is determined. The agreement between observed and simulated white-light images is almost perfect. While collagen provides vital mechanical rigidity to animal tissue, it might also possess optical properties that are useful for vision and camouflage.
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Affiliation(s)
- Euan Jenkinson
- School of Chemistry, University of Edinburgh, David Brewster Road, Edinburgh EH9 3FJ, Scotland
| | - Andrew J Alexander
- School of Chemistry, University of Edinburgh, David Brewster Road, Edinburgh EH9 3FJ, Scotland
| | - Philip J Camp
- School of Chemistry, University of Edinburgh, David Brewster Road, Edinburgh EH9 3FJ, Scotland
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2
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Chang CH, Catchen J, Moran RL, Rivera-Colón AG, Wang YC, Fuller RC. Sequence Analysis and Ontogenetic Expression Patterns of Cone Opsin Genes in the Bluefin Killifish (Lucania goodei). J Hered 2021; 112:357-366. [PMID: 33837393 DOI: 10.1093/jhered/esab017] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2021] [Accepted: 04/06/2021] [Indexed: 11/13/2022] Open
Abstract
Sensory systems allow for the transfer of environmental stimuli into internal cues that can alter physiology and behavior. Many studies of visual systems focus on opsins to compare spectral sensitivity among individuals, populations, and species living in different lighting environments. This requires an understanding of the cone opsins, which can be numerous. The bluefin killifish is a good model for studying the interaction between environments and visual systems as they are found in both clear springs and tannin-stained swamps. We conducted a genome-wide screening and demonstrated that the bluefin killifish has 9 cone opsins: 1 SWS1 (354 nm), 2 SWS2 (SWS2B: 359 nm, SWS2A: 448 nm), 2 RH2 (RH2-2: 476 nm, RH2-1: 537 nm), and 4 LWS (LWS-1: 569 nm, LWS-2: 524 nm, LWS-3: 569 nm, LWS-R: 560 or 569 nm). These 9 cone opsins were located on 4 scaffolds. One scaffold contained the 2 SWS2 and 3 of the 4 LWS opsins in the same syntenic order as found in other cyprinodontoid fishes. We also compared opsin expression in larval and adult killifish under clear water conditions, which mimic springs. Two of the newly discovered opsins (LWS-2 and LWS-3) were expressed at low levels (<0.2%). Whether these opsins make meaningful contributions to visual perception in other contexts (i.e., swamp conditions) is unclear. In contrast, there was an ontogenetic change from using LWS-R to LWS-1 opsin. Bluefin killifish adults may be slightly more sensitive to longer wavelengths, which might be related to sexual selection and/or foraging preferences.
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Affiliation(s)
- Chia-Hao Chang
- TIGP, Biodiversity Program, Tunghai University, Taiwan Boulevard, Taichung City, Taiwan
| | - Julian Catchen
- Department of Evolution, Ecology, and Behavior, University of Illinois at Urbana-Champaign, South Goodwin, Urbana, IL
| | - Rachel L Moran
- Department of Ecology, Evolution, and Behavior, University of Minnesota, 140 Gortner Laboratory, 1479 Gortner Avenue, St. Paul, MN
| | - Angel G Rivera-Colón
- Department of Evolution, Ecology, and Behavior, University of Illinois at Urbana-Champaign, South Goodwin, Urbana, IL
| | - Yu-Chun Wang
- Planning and Information Division, Fisheries Research Institute, Keelung City, Taiwan
| | - Rebecca C Fuller
- Department of Evolution, Ecology, and Behavior, University of Illinois at Urbana-Champaign, 606 East Healey Street, Champaign, IL
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3
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Chang CH, Wang YC, Shao YT, Liu SH. Phylogenetic analysis and ontogenetic changes in the cone opsins of the western mosquitofish (Gambusia affinis). PLoS One 2020; 15:e0240313. [PMID: 33048954 PMCID: PMC7553354 DOI: 10.1371/journal.pone.0240313] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2020] [Accepted: 09/23/2020] [Indexed: 11/25/2022] Open
Abstract
To convert external light into internal neural signal, vertebrates rely on a special group of proteins, the visual opsins. Four of the five types of visual opsins—short-wavelength sensitive 1 (Sws1), short-wavelength sensitive 2 (Sws2), medium-wavelength sensitive (Rh2), and long-wavelength sensitive (Lws)—are expressed in cone cells for scotopic vision, with the fifth, rhodopsin (Rh1), being expressed in rod cells for photopic vision. Fish often display differing ontogenetic cone opsin expression profiles, which may be related to dietary and/or habitat ontogenetic shift. The western mosquitofish (Gambusia affinis) is an aggressive invader that has successfully colonized every continent except Antarctica. The strong invasiveness of this species may be linked to its visual acuity since it can inhabit turbid waters better than other fishes. By genome screening and transcriptome analysis, we identify seven cone opsin genes in the western mosquitofish, including one sws1, two sws2, one rh2, and three lws. The predicted maximal absorbance wavelength (λmax) values of the respective proteins are 353 nm for Sws1, 449 nm for Sws2a, 408 nm for Sws2b, 516 nm for Rh2-1, 571 nm for Lws-1, and 519 nm for Lws-3. Retention of an intron in the lws-r transcript likely renders this visual opsin gene non-functional. Our real-time quantitative PCR demonstrates that adult male and female western mosquitofish do not differ in their cone opsin expression profiles, but we do reveal an ontogenetic shift in cone opsin expression. Compared to adults, larvae express proportionally more sws1 and less lws-1, suggesting that the western mosquitofish is more sensitive to shorter wavelengths in the larval stage, but becomes more sensitive to longer wavelengths in adulthood.
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Affiliation(s)
- Chia-Hao Chang
- TIGP Biodiversity Program, Tunghai University, Taichung City, Taiwan
- Center for Ecology and Environment, Tunghai University, Taichung City, Taiwan
| | - Yu-Chun Wang
- Planning and Information Division, Fisheries Research Institute, Keelung City, Taiwan
| | - Yi Ta Shao
- Institute of Marine Biology, National Taiwan Ocean University, Keelung, Taiwan
| | - Shih-Hui Liu
- Department of Biological Sciences, National Sun Yat-sen University, Kaohsiung City, Taiwan
- * E-mail: ,
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4
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Novales Flamarique I. Light exposure during embryonic and yolk-sac alevin development of Chinook salmon Oncorhynchus tshawytscha does not alter the spectral phenotype of photoreceptors. JOURNAL OF FISH BIOLOGY 2019; 95:214-221. [PMID: 30370922 DOI: 10.1111/jfb.13850] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/03/2018] [Accepted: 10/16/2018] [Indexed: 06/08/2023]
Abstract
Colour vision is mediated by the expression of different visual pigments in photoreceptors of the vertebrate retina. Each visual pigment is a complex of a protein (opsin) and a vitamin A chromophore; alterations to either component affects visual pigment absorbance and, potentially, the visual capabilities of an animal. Many species of fish undergo changes in opsin expression during retinal development. In the case of salmonid fishes the single cone photoreceptors undergo a switch in opsin expression from SWS1 (ultraviolet sensitive) to SWS2 (blue-light sensitive) starting at the yolk-sac alevin stage, around the time when they first experience light. Whether light may initiate this event or produce a plastic response in the various photoreceptors is unknown. In this study, Chinook salmon Oncorhynchus tshawytscha were exposed to light from the embryonic (5 days prior to hatching) into the yolk sac alevin (25 days post hatching) stage and the spectral phenotype of photoreceptors assessed with respect to that of unexposed controls by in situ hybridization with opsin riboprobes. Light exposure did not change the spectral phenotype of photoreceptors, their overall morphology or spatial arrangement. These results concur with those from a variety of fish species and suggest that plasticity in photoreceptor spectral phenotype via changes in opsin expression may not be a widespread occurrence among teleosts.
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Affiliation(s)
- Inigo Novales Flamarique
- Department of Biological Sciences, Simon Fraser University, Burnaby, Canada
- Department of Biology, University of Victoria, Victoria, Canada
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Liu DW, Wang FY, Lin JJ, Thompson A, Lu Y, Vo D, Yan HY, Zakon H. The Cone Opsin Repertoire of Osteoglossomorph Fishes: Gene Loss in Mormyrid Electric Fish and a Long Wavelength-Sensitive Cone Opsin That Survived 3R. Mol Biol Evol 2019; 36:447-457. [PMID: 30590689 DOI: 10.1093/molbev/msy241] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Vertebrates have four classes of cone opsin genes derived from two rounds of genome duplication. These are short wavelength sensitive 1(SWS1), short wavelength sensitive 2(SWS2), medium wavelength sensitive (RH2), and long wavelength sensitive (LWS). Teleosts had another genome duplication at their origin and it is believed that only one of each cone opsin survived the ancestral teleost duplication event. We tested this by examining the retinal cones of a basal teleost group, the osteoglossomorphs. Surprisingly, this lineage has lost the typical vertebrate green-sensitive RH2 opsin gene and, instead, has a duplicate of the LWS opsin that is green sensitive. This parallels the situation in mammalian evolution in which the RH2 opsin gene was lost in basal mammals and a green-sensitive opsin re-evolved in Old World, and independently in some New World, primates from an LWS opsin gene. Another group of fish, the characins, possess green-sensitive LWS cones. Phylogenetic analysis shows that the evolution of green-sensitive LWS opsins in these two teleost groups derives from a common ancestral LWS opsin that acquired green sensitivity. Additionally, the nocturnally active African weakly electric fish (Mormyroideae), which are osteoglossomorphs, show a loss of the SWS1 opsin gene. In comparison with the independently evolved nocturnally active South American weakly electric fish (Gymnotiformes) with a functionally monochromatic LWS opsin cone retina, the presence of SWS2, LWS, and LWS2 cone opsins in mormyrids suggests the possibility of color vision.
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Affiliation(s)
- Da-Wei Liu
- Institute of Molecular and Genomic Medicine, National Health Research Institutes, Zhunan, Miaoli, Taiwan
| | - Feng-Yu Wang
- Taiwan Ocean Research Institute, National Applied Research Laboratories, Kaohsiung, Taiwan
| | - Jinn-Jy Lin
- Biodiversity Research Center, Academia Sinica, Nankang, Taipei, Taiwan
| | - Ammon Thompson
- Department of Integrative Biology, The University of Texas, Austin, TX
| | - Ying Lu
- Department of Integrative Biology, The University of Texas, Austin, TX.,Department of Neuroscience, The University of Texas, Austin, TX
| | - Derek Vo
- Department of Integrative Biology, The University of Texas, Austin, TX
| | - Hong Young Yan
- National Museum of Marine Biology and Aquarium, Chencheng, Pingtung, Taiwan
| | - Harold Zakon
- Department of Integrative Biology, The University of Texas, Austin, TX.,Department of Neuroscience, The University of Texas, Austin, TX
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Chang CH, Yan HY. Plasticity of opsin gene expression in the adult red shiner (Cyprinella lutrensis) in response to turbid habitats. PLoS One 2019; 14:e0215376. [PMID: 30978235 PMCID: PMC6461250 DOI: 10.1371/journal.pone.0215376] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2018] [Accepted: 04/01/2019] [Indexed: 11/30/2022] Open
Abstract
Vision is very important to fish as it is required for foraging food, fighting competitors, fleeing from predators, and finding potential mates. Vertebrates express opsin genes in photoreceptor cells to receive visual signals, and the variety of light levels in aquatic habits has driven fish to evolve multiple opsin genes with expression profiles that are highly plastic. In this study, red shiners (Cyprinella lutrensis) were exposed to four water turbidity treatments and their opsin genes were cloned to elucidate how opsin gene expression could be modulated by ambient light conditions. Opsin gene cloning revealed that these fish have single RH1, SWS1, SWS2 and LWS genes and two RH2 genes. Phylogenetic analysis also indicated that these two RH2 opsin genes-RH2A and RH2B -are in-paralogous. Using quantitative PCR, we found evidence that opsin expression is plastic in adults. Elevated proportional expression of LWS in the cone under ambient light and turbid treatment indicated that the red shiner's visual spectrum displays a red shift in response to increased turbidity.
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Affiliation(s)
- Chia-Hao Chang
- Department of Life Science, Tunghai University, Taichung City, Taiwan
- Center for Ecology and Environment, Tunghai University, Taichung City, Taiwan
| | - Hong Young Yan
- National Museum of Marine Biology & Aquarium, Checheng, Pingtung, Taiwan
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Savelli I, Novales Flamarique I, Iwanicki T, Taylor JS. Parallel opsin switches in multiple cone types of the starry flounder retina: tuning visual pigment composition for a demersal life style. Sci Rep 2018; 8:4763. [PMID: 29555918 PMCID: PMC5859124 DOI: 10.1038/s41598-018-23008-y] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2017] [Accepted: 03/02/2018] [Indexed: 11/29/2022] Open
Abstract
Variable expression of visual pigment proteins (opsins) in cone photoreceptors of the vertebrate retina is a primary determinant of vision plasticity. Switches in opsin expression or variable co-expression of opsins within differentiated cones have been documented for a few rodents and fishes, but the extent of photoreceptor types affected and potential functional significance are largely unknown. Here, we show that both single and double cones in the retina of a flatfish, the starry flounder (Platichthys stellatus), undergo visual pigment changes through opsin switches or variable opsin co-expression. As the post-metamorphic juvenile (i.e., the young asymmetric flatfish with both eyes on one side of the body) grows from ~5 g to ~196 g, some single cones and one member of unequal double cones switched from a visual pigment with maximum wavelength of absorbance, λmax, at shorter wavelengths (437 nm and 527 nm) to one with longer λmax (456 nm and 545 nm, respectively) whereas other cones had intermediate visual pigments (λmax at 445 nm or 536 nm) suggesting co-expression of two opsins. The shift toward longer wavelength absorbing visual pigments was in line with maximizing sensitivity to the restricted light spectrum at greater depths and achromatic detection of overhead targets.
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Affiliation(s)
- Ilaria Savelli
- Department of Biological Sciences, Simon Fraser University, Burnaby, British Columbia, V5A 1S6, Canada
| | - Iñigo Novales Flamarique
- Department of Biological Sciences, Simon Fraser University, Burnaby, British Columbia, V5A 1S6, Canada. .,Department of Biology, University of Victoria, Victoria, British Columbia, V8W 2Y2, Canada.
| | - Tom Iwanicki
- Department of Biology, University of Hawai'i at Mãnoa, Honolulu, Hawai'i, 96822, USA
| | - John S Taylor
- Department of Biology, University of Victoria, Victoria, British Columbia, V8W 2Y2, Canada
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Chang CH, Shao YT, Fu WC, Anraku K, Lin YS, Yan HY. Differentiation of visual spectra and nuptial colorations of two Paratanakia himantegus subspecies (Cyprinoidea: Acheilognathidae) in response to the distinct photic conditions of their habitats. Zool Stud 2015; 54:e43. [PMID: 31966130 DOI: 10.1186/s40555-015-0121-z] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2015] [Accepted: 05/06/2015] [Indexed: 11/10/2022]
Abstract
BACKGROUND Vision, an important sensory modality of many animals, exhibits plasticity in that it adapts to environmental conditions to maintain its sensory efficiency. Nuptial coloration is used to attract mates and hence should be tightly coupled to vision. In Taiwan, two closely related bitterlings (Paratanakia himantegus himantegus and Paratanakia himantegus chii) with different male nuptial colorations reside in different habitats. We compared the visual spectral sensitivities of these subspecies with the ambient light spectra of their habitats to determine whether their visual abilities correspond with photic parameters and correlate with nuptial colorations. RESULTS Theelectroretinogram (ERG) results revealed that the relative spectral sensitivity of P.h. himantegus was higher at 670 nm, but lower at 370 nm, than the sensitivity of P. h. chii. Both bitterlings could perceive and reflect UV light, but the UV reflection patterns differed between genders. Furthermore, the relative irradiance intensity of the light spectra in the habitat of P. h. himantegus was higher at long wavelengths (480-700 nm), but lower at short wavelengths (350-450 nm), than the light spectra in the habitats of P. h.chii. CONCLUSIONS Two phylogenetically closely related bitterlings, P. h. himantegus and P. h. chii, dwell in different waters and exhibit different nuptial colorations and spectral sensitivities, which may be the results of speciation by sensory drive. Sensory ability and signal diversity accommodating photic environment may promote diversity of bitterling fishes. UV light was demonstrated to be a possible component of bitterling visual communication. The UV cue may assist bitterlings in genderidentification.
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Affiliation(s)
- Chia-Hao Chang
- Department of Biological Science and Technology, National Chiao Tung University, Hsinchu, Taiwan.,Department of Biology, St. Louis University, St. Louis, MO, USA
| | - Yi Ta Shao
- Sensory Physiology Laboratory, Marine Research Station, Academia Sinica, I-Lan, Taiwan.,Present Address: Institute of Marine Biology, National Taiwan Ocean University, Keelung, Taiwan
| | - Wen-Chung Fu
- Sensory Physiology Laboratory, Marine Research Station, Academia Sinica, I-Lan, Taiwan
| | - Kazuhiko Anraku
- Faculty of Fisheries, Kagoshima University, Kagoshima, Japan
| | - Yeong-Shin Lin
- Department of Biological Science and Technology, National Chiao Tung University, Hsinchu, Taiwan.,Institute of Bioinformatics and Systems Biology, National Chiao Tung University, Hsinchu, Taiwan
| | - Hong Young Yan
- Sensory Physiology Laboratory, Marine Research Station, Academia Sinica, I-Lan, Taiwan.,Hanse-Wissenschaftskolleg Institute of Advanced Study, Delmenhorst, Germany
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Abstract
The visual pigment rhodopsin (rh1) constitutes the first step in the sensory transduction cascade in the rod photoreceptors of the vertebrate eye, forming the basis of vision at low light levels. In most vertebrates, rhodopsin is a single-copy gene whose function in rod photoreceptors is highly conserved. We found evidence for a second rhodopsin-like gene (rh1-2) in the zebrafish genome. This novel gene was not the product of a zebrafish-specific gene duplication event and contains a number of unique amino acid substitutions. Despite these differences, expression of rh1-2 in vitro yielded a protein that not only bound chromophore, producing an absorption spectrum in the visible range (λmax ≈ 500 nm), but also activated in response to light. Unlike rh1, rh1-2 is not expressed during the first 4 days of embryonic development; it is expressed in the retina of adult fish but not the brain or muscle. Similar rh1-2 sequences were found in two other Danio species, as well as a more distantly related cyprinid, Epalzeorhynchos bicolor. While sequences were only identified in cyprinid fish, phylogenetic analyses suggest an older origin for this gene family. Our study suggests that rh1-2 is a functional opsin gene that is expressed in the retina later in development. The discovery of a new previously uncharacterized opsin gene in zebrafish retina is surprising given its status as a model system for studies of vertebrate vision and visual development.
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