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Gerald H. Jacobs - One of the best experts on this subject based on the ideXlab platform.
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Photopigments and the dimensionality of animal color vision
Neuroscience and biobehavioral reviews, 2017Co-Authors: Gerald H. JacobsAbstract:Abstract Early color-matching studies established that normal human color vision is trichromatic. Subsequent research revealed a causal link between trichromacy and the presence in the retina of three classes of cone Photopigments. Over the years, measurements of the Photopigment complements of other species have expanded greatly and these are frequently used to predict the dimensionality of an animal’s color vision. This review provides an account of how the linkage between the number of active Photopigments and the dimensions of human color vision developed, summarizes the various mechanisms that can impact Photopigment spectra and number, and provides an across-species survey to examine cases where the Photopigment link to the dimensionality of color vision has been claimed. The literature reveals numerous instances where the human model fails to account for the ways in which the visual systems of other animals exploit information obtained from the presence of multiple Photopigments in support of their behavior.
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losses of functional opsin genes short wavelength cone Photopigments and color vision a significant trend in the evolution of mammalian vision
Visual Neuroscience, 2013Co-Authors: Gerald H. JacobsAbstract:All mammalian cone Photopigments are derived from the operation of representatives from two opsin gene families (SWS1 and LWS in marsupial and eutherian mammals; SWS2 and LWS in monotremes), a process that produces cone pigments with respective peak sensitivities in the short and middle-to-long wavelengths. With the exception of a number of primate taxa, the modal pattern for mammals is to have two types of cone Photopigment, one drawn from each of the gene families. In recent years, it has been discovered that the SWS1 opsin genes of a widely divergent collection of eutherian mammals have accumulated mutational changes that render them nonfunctional. This alteration reduces the retinal complements of these species to a single cone type, thus rendering ordinary color vision impossible. At present, several dozen species from five mammalian orders have been identified as falling into this category, but the total number of mammalian species that have lost short-wavelength cones in this way is certain to be much larger, perhaps reaching as high as 10% of all species. A number of circumstances that might be used to explain this widespread cone loss can be identified. Among these, the single consistent fact is that the species so affected are nocturnal or, if they are not technically nocturnal, they at least feature retinal organizations that are typically associated with that lifestyle. At the same time, however, there are many nocturnal mammals that retain functional short-wavelength cones. Nocturnality thus appears to set the stage for loss of functional SWS1 opsin genes in mammals, but it cannot be the sole circumstance.
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Transgenic mice expressing a functional human Photopigment.
Investigative ophthalmology & visual science, 1998Co-Authors: Salam A. Shaaban, Michael A. Crognale, Gerald H. Jacobs, Jack B. Calderone, Jing Huang, Samir S. DeebAbstract:PURPOSE. Changes in retinal Photopigments represent a fundamental step in the evolution of visual systems, in that addition of new pigment types or alterations in the spectral absorption properties of existing pigments modify visual capacities and thus open new visual worlds. To provide a tool that would allow direct examination of the changes caused by the presence of novel Photopigments, this study was designed to determine whether a gene encoding a human cone Photopigment introduced into the mouse genome would be expressed in a cone-specific manner and would support phototransduction. METHODS. Mice transgenic for the human long wavelength-sensitive (L) Photopigment were generated by microinjection of fertilized mouse eggs. RNA expression in different tissues was monitored by reverse transcription-polymerase chain reaction analysis. Photopigment protein was localized in retinal cross sections and wholemounts by antibody staining. Light transduction of the cone Photopigments was assessed by flicker photometric electroretinography (ERG). RESULTS. The human transgene was expressed specifically in the mouse cones in quantities comparable to those of the mouse middle wavelength-sensitive (M) pigment gene. Immunocytochemical analysis showed that the human L pigment was abundantly synthesized in most mouse cones, was translocated to the outer segments, and caused no detectable cone degeneration. Electroretinographic spectral sensitivity analysis showed that the human L pigment was efficient in eliciting an electrical response. The degree of expression of the transgene in the two founders correlated well with the spectral responsivity of the ERG. CONCLUSIONS. The human L Photopigment transduces light efficiently in mouse cones, implying that all protein domains necessary for efficient interaction with intracellular transport and signal transduction machineries in mouse cones have been conserved through evolution. The expression of the human L Photopigment gene in both classes of cone of the mouse retina indicates that the transgene did not have the regulatory elements necessary for restricting its expression to mouse M cones or that such elements are not recognized in mouse UV-sensitive cones. (Invest Ophthalmol Vis Sci. 1998;39:1036-1043)
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Primate Photopigments and primate color vision.
Proceedings of the National Academy of Sciences of the United States of America, 1996Co-Authors: Gerald H. JacobsAbstract:The past 15 years have brought much progress in our understanding of several basic features of primate color vision. There has been particular success in cataloging the spectral properties of the cone Photopigments found in retinas of a number of primate species and in elucidating the relationship between cone opsin genes and their Photopigment products. Direct studies of color vision show that there are several modal patterns of color vision among groupings of primates: (i) Old World monkeys, apes, and humans all enjoy trichromatic color vision, although the former two groups do not seem prone to the polymorphic variations in color vision that are characteristic of people; (ii) most species of New World monkeys are highly polymorphic, with individual animals having any of several types of dichromatic or trichromatic color vision; (iii) less is known about color vision in prosimians, but evidence suggests that at least some diurnal species have dichromatic color vision; and (iv) some nocturnal primates may lack color vision completely. In many cases the Photopigments and Photopigment gene arrangements underlying these patterns have been revealed and, as a result, hints are emerging about the evolution of color vision among the primates.
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spectral sensitivity and Photopigments of a nocturnal prosimian the bushbaby otolemur crassicaudatus
American Journal of Primatology, 1996Co-Authors: Jess F. Deegan, Gerald H. JacobsAbstract:: Earlier studies yielded conflicting conclusions on the types of photoreceptors and Photopigments found in the eyes of nocturnal prosimians. In this investigation a noninvasive electrophysiological procedure, electroretinogram flicker photometry, was employed to measure scotopic and photopic spectral sensitivity in the thick-tailed bushbaby (Otolemur crassicaudatus). The scotopic spectral sensitivity function of the bushbaby has a peak of about 507 nm. Under photopic test conditions, spectral sensitivity shifts toward the longer wavelengths. The results from a series of adaptation experiments indicate that the cones of the bushbaby retina contain only a single type of cone Photopigment (peak sensitivity at about 545 nm). One implication from this result is that these animals do not have color vision. The Photopigment arrangement of the bushbaby is different from that earlier found in diurnal and crepuscular prosimians but is similar to that of the owl monkey, the only nocturnal simian. © 1996 Wiley-Liss, Inc.
Russell G Foster - One of the best experts on this subject based on the ideXlab platform.
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an extended family of novel vertebrate Photopigments is widely expressed and displays a diversity of function
Genome Research, 2015Co-Authors: W I Davies, T.k. Tamai, Russell G Foster, David Whitmore, Lei Zheng, Jason Rihel, Mark W HankinsAbstract:Light affects animal physiology and behavior more than simply through classical visual, image-forming pathways. Nonvisual photoreception regulates numerous biological systems, including circadian entrainment, DNA repair, metabolism, and behavior. However, for the majority of these processes, the photoreceptive molecules involved are unknown. Given the diversity of photophysiological responses, the question arises whether a single Photopigment or a greater diversity of proteins within the opsin superfamily detect photic stimuli. Here, a functional genomics approach identified the full complement of Photopigments in a highly light-sensitive model vertebrate, the zebrafish (Danio rerio), and characterized their tissue distribution, expression levels, and biochemical properties. The results presented here reveal the presence of 42 distinct genes encoding 10 classical visual Photopigments and 32 nonvisual opsins, including 10 novel opsin genes comprising four new pigment classes. Consistent with the presence of light-entrainable circadian oscillators in zebrafish, all adult tissues examined expressed two or more opsins, including several novel opsins. Spectral and electrophysiological analyses of the new opsins demonstrate that they form functional Photopigments, each with unique chromophore-binding and wavelength specificities. This study has revealed a remarkable number and diversity of Photopigments in zebrafish, the largest number so far discovered for any vertebrate. Found in amphibians, reptiles, birds, and all three mammalian clades, most of these genes are not restricted to teleosts. Therefore, nonvisual light detection is far more complex than initially appreciated, which has significant biological implications in understanding photoreception in vertebrates.
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Vertebrate ancient opsin Photopigment spectra and the avian photoperiodic response
Biology letters, 2011Co-Authors: Wayne I. L. Davies, Mark W Hankins, Michael Turton, Stephanie Halford, Stuart N. Peirson, Brian K. Follett, José M. García-fernández, Peter J. Sharp, Russell G FosterAbstract:In mammals, photoreception is restricted to cones, rods and a subset of retinal ganglion cells. By contrast, non-mammalian vertebrates possess many extraocular photoreceptors but in many cases the role of these photoreceptors and their underlying Photopigments is unknown. In birds, deep brain photoreceptors have been shown to sense photic changes in daylength (photoperiod) and mediate seasonal reproduction. Nonetheless, the specific identity of the opsin Photopigment 'sensor' involved has remained elusive. Previously, we showed that vertebrate ancient (VA) opsin is expressed in avian hypothalamic neurons and forms a photosensitive molecule. However, a direct functional link between VA opsin and the regulation of seasonal biology was absent. Here, we report the in vivo and in vitro absorption spectra (λ(max) = ~490 nm) for chicken VA Photopigments. Furthermore, the spectral sensitivity of these Photopigments match the peak absorbance of the avian photoperiodic response (λ(max) = 492 nm) and permits maximum photon capture within the restricted light environment of the hypothalamus. Such a correspondence argues strongly that VA opsin plays a key role in regulating seasonal reproduction in birds.
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Functional diversity of melanopsins and their global expression in the teleost retina
Cellular and Molecular Life Sciences, 2011Co-Authors: Wayne L. Davies, T.k. Tamai, Michael Turton, Steven Hughes, Stephanie Halford, Russell G Foster, David Whitmore, Lei Zheng, Mark W HankinsAbstract:Melanopsin (OPN4) is an opsin Photopigment that, in mammals, confers photosensitivity to retinal ganglion cells and regulates circadian entrainment and pupil constriction. In non-mammalian species, two forms of opn4 exist, and are classified into mammalian-like (m) and non-mammalian-like (x) clades. However, far less is understood of the function of this Photopigment family. Here we identify in zebrafish five melanopsins (opn4m-1, opn4m-2, opn4m-3, opn4x-1 and opn4x-2), each encoding a full-length opsin G protein. All five genes are expressed in the adult retina in a largely non-overlapping pattern, as revealed by RNA in situ hybridisation and immunocytochemistry, with at least one melanopsin form present in all neuronal cell types, including cone photoreceptors. This raises the possibility that the teleost retina is globally light sensitive. Electrophysiological and spectrophotometric studies demonstrate that all five zebrafish melanopsins encode a functional Photopigment with peak spectral sensitivities that range from 470 to 484 nm, with opn4m-1 and opn4m-3 displaying invertebrate-like bistability, where the retinal chromophore interchanges between cis- and trans-isomers in a light-dependent manner and remains within the opsin binding pocket. In contrast, opn4m-2, opn4x-1 and opn4x-2 are monostable and function more like classical vertebrate-like Photopigments, where the chromophore is converted from 11-cis to all-trans retinal upon absorption of a photon, hydrolysed and exits from the binding pocket of the opsin. It is thought that all melanopsins exhibit an invertebrate-like bistability biochemistry. Our novel findings, however, reveal the presence of both invertebrate-like and vertebrate-like forms of melanopsin in the teleost retina, and indicate that Photopigment bistability is not a universal property of the melanopsin family. The functional diversity of these teleost melanopsins, together with their widespread expression pattern within the retina, suggests that melanopsins confer global photosensitivity to the teleost retina and might allow for direct “fine-tuning” of retinal circuitry and physiology in the dynamic light environments found in aquatic habitats.
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the evolution of irradiance detection melanopsin and the non visual opsins
Philosophical Transactions of the Royal Society B, 2009Co-Authors: Stuart N. Peirson, Stephanie Halford, Russell G FosterAbstract:Circadian rhythms are endogenous 24 h cycles that persist in the absence of external time cues. These rhythms provide an internal representation of day length and optimize physiology and behaviour to the varying demands of the solar cycle. These clocks require daily adjustment to local time and the primary time cue (zeitgeber) used by most vertebrates is the daily change in the amount of environmental light (irradiance) at dawn and dusk, a process termed photoentrainment. Attempts to understand the photoreceptor mechanisms mediating non-image-forming responses to light, such as photoentrainment, have resulted in the discovery of a remarkable array of different photoreceptors and Photopigment families, all of which appear to use a basic opsin/vitamin A-based Photopigment biochemistry. In non-mammalian vertebrates, specialized photoreceptors are located within the pineal complex, deep brain and dermal melanophores. There is also strong evidence in fish and amphibians for the direct photic regulation of circadian clocks in multiple tissues. By contrast, mammals possess only ocular photoreceptors. However, in addition to the image-forming rods and cones of the retina, there exists a third photoreceptor system based on a subset of melanopsin-expressing photosensitive retinal ganglion cells (pRGCs). In this review, we discuss the range of vertebrate photoreceptors and their opsin Photopigments, describe the melanopsin/pRGC system in some detail and then finally consider the molecular evolution and sensory ecology of these non-image-forming photoreceptor systems.
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melanopsin an exciting Photopigment
Trends in Neurosciences, 2008Co-Authors: Mark W Hankins, Stuart N. Peirson, Russell G FosterAbstract:The discovery that mice lacking rods and cones are capable of regulating their circadian rhythms by light provided the conceptual framework for the discovery of an entirely new photoreceptor system within the mammalian eye. We now know that a small subset of retinal ganglion cells are directly photosensitive and utilize an opsin/vitamin A-based Photopigment called melanopsin maximally sensitive in the blue part of the spectrum. We also know that these photosensitive retinal ganglion cells mediate a broad range of physiological responses to light, ranging from the regulation of circadian rhythms to pupil constriction. Most recently, it has become clear that the melanopsins are only distantly related to visual pigments and in terms of their biochemistry share more in common with invertebrate Photopigments. Here we outline the discovery of this remarkable new photoreceptor system, review the structure of melanopsin and conclude with a working model of melanopsin phototransduction.
James K. Bowmaker - One of the best experts on this subject based on the ideXlab platform.
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Pineal organs of deep-sea fish: Photopigments and structure.
Journal of Experimental Biology, 2004Co-Authors: James K. Bowmaker, Hans-joachim WagnerAbstract:SUMMARY We have examined the morphology and Photopigments of the pineal organs from a number of mesopelagic fish, including representatives of the hatchet fish (Sternoptychidae), scaly dragon-fish (Chauliodontidae) and bristlemouths (Gonostomidae). Although these fish were caught at depths of between 500 and 1000 m, the morphological organisation of their pineal organs is remarkably similar to that of surface-dwelling fish. Photoreceptor inner and outer segments protrude into the lumen of the pineal vesicle, and the outer segment is composed of a stack of up to 20 curved disks that form a cap-like cover over the inner segment. In all species, the pineal Photopigment was spectrally distinct from the retinal rod pigment, with λ max displaced to longer wavelengths, between ∼485 and 503 nm. We also investigated the pineal organ of the deep demersal eel, Synaphobranchus kaupi , caught at depths below 2000 m, which possesses a rod visual pigment withλ max at 478 nm, but the pineal pigment hasλ max at ∼515 nm. In one species of hatchet fish, Argyropelecus affinis , two spectral classes of pinealocyte were identified, both spectrally distinct from the retinal rod Photopigment.
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Pineal organs of deep-sea fish: Photopigments and structure.
The Journal of experimental biology, 2004Co-Authors: James K. Bowmaker, Hans-joachim WagnerAbstract:We have examined the morphology and Photopigments of the pineal organs from a number of mesopelagic fish, including representatives of the hatchet fish (Sternoptychidae), scaly dragon-fish (Chauliodontidae) and bristlemouths (Gonostomidae). Although these fish were caught at depths of between 500 and 1000 m, the morphological organisation of their pineal organs is remarkably similar to that of surface-dwelling fish. Photoreceptor inner and outer segments protrude into the lumen of the pineal vesicle, and the outer segment is composed of a stack of up to 20 curved disks that form a cap-like cover over the inner segment. In all species, the pineal Photopigment was spectrally distinct from the retinal rod pigment, with lambdamax displaced to longer wavelengths, between approximately 485 and 503 nm. We also investigated the pineal organ of the deep demersal eel, Synaphobranchus kaupi, caught at depths below 2000 m, which possesses a rod visual pigment with lambdamax at 478 nm, but the pineal pigment has lambdamax at approximately 515 nm. In one species of hatchet fish, Argyropelecus affinis, two spectral classes of pinealocyte were identified, both spectrally distinct from the retinal rod Photopigment.
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The polymorphic Photopigments of the marmoset: spectral tuning and genetic basis.
The EMBO journal, 1992Co-Authors: A.j. Williams, David M. Hunt, James K. Bowmaker, John D. MollonAbstract:The marmoset (Callithrix jacchus jacchus), a South American monkey, is polymorphic for the middle- to long-wave cone Photopigments: the three variant pigments have spectral peaks at 543, 556 and 563 nm. Comparisons of the deduced amino acid sequences of these pigments indicate that the variations in spectral sensitivity are associated with the presence or absence of hydroxyl-bearing residues at sites 180 and 285; but, in contrast to the additive hypothesis of Neitz et al. (1991), we propose that adjustments at site 233 may also be required to produce viable long-wave and middle-wave pigments. Within a family group of monkeys, we find that a restriction site polymorphism in the Photopigment gene segregates in a way that is consistent with the single X-linked gene hypothesis previously proposed on the basis of the Photopigment types present in male and female marmosets.
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sequence divergence and copy number of the middle and long wave Photopigment genes in old world monkeys
Proceedings of The Royal Society B: Biological Sciences, 1992Co-Authors: Rachel E Ibbotson, David M. Hunt, James K. Bowmaker, J D MollonAbstract:We have studied the sequence and organization of the genes for the middle-wave (MW) and long-wave (LW) cone Photopigment genes in six species of Old World monkeys. Previous studies have shown that the MW and LW pigments of all six species exhibit peak sensitivities near 535 nm and 565 nm, respectively, and thus resemble the equivalent human pigments. In the case of man, the protein components of the MW and LW Photopigments differ by 15 amino acids, although only seven of these differences involve nonhomologous substitutions and are therefore candidates for a role in spectral tuning. Regions corresponding to exons 4 and 5 of these genes, and including five such candidate sites, were sequenced in the Old World monkeys. In contrast to the equivalent human genes, substitutions were found at two of these sites, position 233 and 309 of the MW gene in all six species. The role of amino acid substitutions in the spectral tuning of these Photopigments is discussed. A comparision of the nucleotide sequences of the MW and LW genes provides evidence for sequence homogenization within species; the role of gene conversion in the evolution of these genes is discussed. The close juxtaposition and homology of the MW and LW genes on the X chromosome is thought to underlie the high frequency of colour vision defects in man and the presence in many individuals of extra copies of the MW gene. A study of a group of talapoin (Ceropithecus talapoin) monkeys has revealed a similar numerical polymorphism for this gene to that present in man. In contrast to the situation in man, where the MW and LW genes may contain a shortened first intron, restriction digests of genomic DNA showed that the size of this intron does not differ across the six species of Old World monkeys examined.
Hans-joachim Wagner - One of the best experts on this subject based on the ideXlab platform.
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Pineal organs of deep-sea fish: Photopigments and structure.
Journal of Experimental Biology, 2004Co-Authors: James K. Bowmaker, Hans-joachim WagnerAbstract:SUMMARY We have examined the morphology and Photopigments of the pineal organs from a number of mesopelagic fish, including representatives of the hatchet fish (Sternoptychidae), scaly dragon-fish (Chauliodontidae) and bristlemouths (Gonostomidae). Although these fish were caught at depths of between 500 and 1000 m, the morphological organisation of their pineal organs is remarkably similar to that of surface-dwelling fish. Photoreceptor inner and outer segments protrude into the lumen of the pineal vesicle, and the outer segment is composed of a stack of up to 20 curved disks that form a cap-like cover over the inner segment. In all species, the pineal Photopigment was spectrally distinct from the retinal rod pigment, with λ max displaced to longer wavelengths, between ∼485 and 503 nm. We also investigated the pineal organ of the deep demersal eel, Synaphobranchus kaupi , caught at depths below 2000 m, which possesses a rod visual pigment withλ max at 478 nm, but the pineal pigment hasλ max at ∼515 nm. In one species of hatchet fish, Argyropelecus affinis , two spectral classes of pinealocyte were identified, both spectrally distinct from the retinal rod Photopigment.
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Pineal organs of deep-sea fish: Photopigments and structure.
The Journal of experimental biology, 2004Co-Authors: James K. Bowmaker, Hans-joachim WagnerAbstract:We have examined the morphology and Photopigments of the pineal organs from a number of mesopelagic fish, including representatives of the hatchet fish (Sternoptychidae), scaly dragon-fish (Chauliodontidae) and bristlemouths (Gonostomidae). Although these fish were caught at depths of between 500 and 1000 m, the morphological organisation of their pineal organs is remarkably similar to that of surface-dwelling fish. Photoreceptor inner and outer segments protrude into the lumen of the pineal vesicle, and the outer segment is composed of a stack of up to 20 curved disks that form a cap-like cover over the inner segment. In all species, the pineal Photopigment was spectrally distinct from the retinal rod pigment, with lambdamax displaced to longer wavelengths, between approximately 485 and 503 nm. We also investigated the pineal organ of the deep demersal eel, Synaphobranchus kaupi, caught at depths below 2000 m, which possesses a rod visual pigment with lambdamax at 478 nm, but the pineal pigment has lambdamax at approximately 515 nm. In one species of hatchet fish, Argyropelecus affinis, two spectral classes of pinealocyte were identified, both spectrally distinct from the retinal rod Photopigment.
Jess F. Deegan - One of the best experts on this subject based on the ideXlab platform.
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spectral sensitivity and Photopigments of a nocturnal prosimian the bushbaby otolemur crassicaudatus
American Journal of Primatology, 1996Co-Authors: Jess F. Deegan, Gerald H. JacobsAbstract:: Earlier studies yielded conflicting conclusions on the types of photoreceptors and Photopigments found in the eyes of nocturnal prosimians. In this investigation a noninvasive electrophysiological procedure, electroretinogram flicker photometry, was employed to measure scotopic and photopic spectral sensitivity in the thick-tailed bushbaby (Otolemur crassicaudatus). The scotopic spectral sensitivity function of the bushbaby has a peak of about 507 nm. Under photopic test conditions, spectral sensitivity shifts toward the longer wavelengths. The results from a series of adaptation experiments indicate that the cones of the bushbaby retina contain only a single type of cone Photopigment (peak sensitivity at about 545 nm). One implication from this result is that these animals do not have color vision. The Photopigment arrangement of the bushbaby is different from that earlier found in diurnal and crepuscular prosimians but is similar to that of the owl monkey, the only nocturnal simian. © 1996 Wiley-Liss, Inc.
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Photopigments and color vision in the nocturnal monkey,Aotus
Vision Research, 1993Co-Authors: Gerald H. Jacobs, Michael A. Crognale, Jay Neitz, Jess F. Deegan, Maureen NeitzAbstract:The owl monkey (Aotus tridrgutus) is the only nocturnal monkey. The Photopigments of Aotus and the relationship between these Photopigments and visual discrimination were examined through (1) an analysis of the tlicker photometric electroretinogram (ERG), (2) psychophysical tests of visual sensitivity and color vision, and (3) a search for the presence of the Photopigment gene necessary for the production of a short-wavelength sensitive (SWS) Photopigment. Roth electrophysiological and behavioral measurements indicate that in addition to a rod Photopigment the retina of this primate contains only one other Photopigment type-a cone pigment having a spectral peak cu 543 nm. Earlier results that suggested these monkeys can make crude color discriminations are interpreted as probably resulting from the joint exploitation of signals from rods and cones. Although Aotus has no functional SWS Photopigment, hybridization analysis shows that A&us has a pigment gene that is highly homologous to the human SWS Photopigment gene. Aotus trivirgatus Cone Photopigments Monkey color vision Monochromacy Photopigment genes Evolution of color vision
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Cone Photopigments in nocturnal and diurnal procyonids
Journal of Comparative Physiology A-neuroethology Sensory Neural and Behavioral Physiology, 1992Co-Authors: Gerald H. Jacobs, Jess F. DeeganAbstract:Procyonids are small, New World carnivores distributed among some 6 genera. Electroretinogram (ERG) flicker photometry was used to measure the spectra of the cone Photopigments for members of two nocturnal species, the raccoon (Procyon lotor) and the kinkajou (Potos flavus), and a diurnal species, the coati (Nasua nasua). Each of the 3 has a class of cone Photopigment with maximum sensitivity in the middle to long wavelengths. The spectral positioning of this cone is different for the three. Whereas the raccoon and kinkajou are monochromatic, the diurnal coati is a dichromat having an additional class of cone Photopigment with peak sensitivity close to 433 nm.
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Cone Photopigments in nocturnal and diurnal procyonids
Journal of Comparative Physiology A-neuroethology Sensory Neural and Behavioral Physiology, 1992Co-Authors: Gerald H. Jacobs, Jess F. DeeganAbstract:Procyonids are small, New World carnivores distributed among some 6 genera. Electroretinogram (ERG) flicker photometry was used to measure the spectra of the cone Photopigments for members of two nocturnal species, the raccoon (Procyon lotor) and the kinkajou (Potos flavus), and a diurnal species, the coati (Nasua nasua). Each of the 3 has a class of cone Photopigment with maximum sensitivity in the middle to long wavelengths. The spectral positioning of this cone is different for the three. Whereas the raccoon and kinkajou are monochromatic, the diurnal coati is a dichromat having an additional class of cone Photopigment with peak sensitivity close to 433 nm.