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1

Genomic organization of duplicated short wave-sensitive and long wave-sensitive opsin genes in the green swordtail, Xiphophorus helleri  

Microsoft Academic Search

BACKGROUND: Long wave-sensitive (LWS) opsin genes have undergone multiple lineage-specific duplication events throughout the evolution of teleost fishes. LWS repertoire expansions in live-bearing fishes (family Poeciliidae) have equipped multiple species in this family with up to four LWS genes. Given that color vision, especially attraction to orange male coloration, is important to mate choice within poeciliids, LWS opsins have been

Corey T Watson; Krzysztof P Lubieniecki; Ellis Loew; William S Davidson; Felix Breden

2010-01-01

2

The molecular basis of color vision in colorful fish: Four Long Wave-Sensitive (LWS) opsins in guppies (Poecilia reticulata) are defined by amino acid substitutions at key functional sites  

Microsoft Academic Search

BACKGROUND: Comparisons of functionally important changes at the molecular level in model systems have identified key adaptations driving isolation and speciation. In cichlids, for example, long wavelength-sensitive (LWS) opsins appear to play a role in mate choice and male color variation within and among species. To test the hypothesis that the evolution of elaborate coloration in male guppies (Poecilia reticulata)

Matthew N Ward; Allison M Churcher; Kevin J Dick; Chris RJ Laver; Greg L Owens; Megan D Polack; Pam R Ward; Felix Breden; John S Taylor

2008-01-01

3

LIA: LWS Interactive Analysis  

NASA Astrophysics Data System (ADS)

The Long Wavelength Spectrometer (LWS) was one of two complementary spectrometers on the Infrared Space Observatory (ISO). LIA (LWS Interactive Analysis) is used for processing data from the LWS. It provides access to the different processing steps, including visualization of intermediate products and interactive manipulation of the data at each stage.

Infrared Space Observatory (ISO) Development Team

2014-08-01

4

Divergent selection for opsin gene variation in guppy (Poecilia reticulata) populations of Trinidad and Tobago.  

PubMed

The guppy is known to exhibit remarkable interindividual variations in spectral sensitivity of middle to long wavelength-sensitive (M/LWS) cone photoreceptor cells. The guppy has four M/LWS-type opsin genes (LWS-1, LWS-2, LWS-3 and LWS-4) that are considered to be responsible for this sensory variation. However, the allelic variation of the opsin genes, particularly in terms of their absorption spectrum, has not been explored in wild populations. Thus, we examined nucleotide variations in the four M/LWS opsin genes as well as blue-sensitive SWS2-B and ultraviolet-sensitive SWS1 opsin genes for comparison and seven non-opsin nuclear loci as reference genes in 10 guppy populations from various light environments in Trinidad and Tobago. For the first time, we discovered a potential spectral variation (180 Ser/Ala) in LWS-1 that differed at an amino acid site known to affect the absorption spectra of opsins. Based on a coalescent simulation of the nucleotide variation of the reference genes, we showed that the interpopulation genetic differentiation of two opsin genes was significantly larger than the neutral expectation. Furthermore, this genetic differentiation was significantly related to differences in dissolved oxygen (DO) level, and it was not explained by the spatial distance between populations. The DO levels are correlated with eutrophication that possibly affects the color of aquatic environments. These results suggest that the population diversity of opsin genes is significantly driven by natural selection and that the guppy could adapt to various light environments through color vision changes. PMID:24690753

Tezuka, A; Kasagi, S; van Oosterhout, C; McMullan, M; Iwasaki, W M; Kasai, D; Yamamichi, M; Innan, H; Kawamura, S; Kawata, M

2014-11-01

5

Gene Duplication and Divergence of Long Wavelength-Sensitive Opsin Genes in the Guppy, Poecilia reticulata  

Microsoft Academic Search

Female preference for male orange coloration in the genus Poecilia suggests a role for duplicated long wavelength-sensitive (LWS) opsin genes in facilitating behaviors related to mate choice in these species. Previous work has shown that LWS gene duplication in this genus has resulted in expansion of long wavelength visual capacity as determined by microspectrophotometry\\u000a (MSP). However, the relationship between LWS

Corey T. Watson; Suzanne M. Gray; Margarete Hoffmann; Krzysztof P. Lubieniecki; Jeffrey B. Joy; Ben A. Sandkam; Detlef Weigel; Ellis Loew; Christine Dreyer; William S. Davidson; Felix Breden

2011-01-01

6

A Fish Eye Out of Water: Ten Visual Opsins in the Four-Eyed Fish, Anableps anableps  

PubMed Central

The “four-eyed” fish Anableps anableps has numerous morphological adaptations that enable above and below-water vision. Here, as the first step in our efforts to identify molecular adaptations for aerial and aquatic vision in this species, we describe the A. anableps visual opsin repertoire. We used PCR, cloning, and sequencing to survey cDNA using unique primers designed to amplify eight sequences from five visual opsin gene subfamilies, SWS1, SWS2, RH1, RH2, and LWS. We also used Southern blotting to count opsin loci in genomic DNA digested with EcoR1 and BamH1. Phylogenetic analyses confirmed the identity of all opsin sequences and allowed us to map gene duplication and divergence events onto a tree of teleost fish. Each of the gene-specific primer sets produced an amplicon from cDNA, indicating that A. anableps possessed and expressed at least eight opsin genes. A second PCR-based survey of genomic and cDNA uncovered two additional LWS genes. Thus, A. anableps has at least ten visual opsins and all but one were expressed in the eyes of the single adult surveyed. Among these ten visual opsins, two have key site haplotypes not found in other fish. Of particular interest is the A. anableps-specific opsin in the LWS subfamily, S180?, with a SHYAA five key site haplotype. Although A. anableps has a visual opsin gene repertoire similar to that found in other fishes in the suborder Cyprinodontoidei, the LWS opsin subfamily has two loci not found in close relatives, including one with a key site haplotype not found in any other fish species. A. anableps opsin sequence data will be used to design in situ probes allowing us to test the hypothesis that opsin gene expression differs in the distinct ventral and dorsal retinas found in this species. PMID:19551143

Owens, Gregory L.; Windsor, Diana J.; Mui, Justin; Taylor, John S.

2009-01-01

7

Rod monochromacy and the coevolution of cetacean retinal opsins.  

PubMed

Cetaceans have a long history of commitment to a fully aquatic lifestyle that extends back to the Eocene. Extant species have evolved a spectacular array of adaptations in conjunction with their deployment into a diverse array of aquatic habitats. Sensory systems are among those that have experienced radical transformations in the evolutionary history of this clade. In the case of vision, previous studies have demonstrated important changes in the genes encoding rod opsin (RH1), short-wavelength sensitive opsin 1 (SWS1), and long-wavelength sensitive opsin (LWS) in selected cetaceans, but have not examined the full complement of opsin genes across the complete range of cetacean families. Here, we report protein-coding sequences for RH1 and both color opsin genes (SWS1, LWS) from representatives of all extant cetacean families. We examine competing hypotheses pertaining to the timing of blue shifts in RH1 relative to SWS1 inactivation in the early history of Cetacea, and we test the hypothesis that some cetaceans are rod monochomats. Molecular evolutionary analyses contradict the "coastal" hypothesis, wherein SWS1 was pseudogenized in the common ancestor of Cetacea, and instead suggest that RH1 was blue-shifted in the common ancestor of Cetacea before SWS1 was independently knocked out in baleen whales (Mysticeti) and in toothed whales (Odontoceti). Further, molecular evidence implies that LWS was inactivated convergently on at least five occasions in Cetacea: (1) Balaenidae (bowhead and right whales), (2) Balaenopteroidea (rorquals plus gray whale), (3) Mesoplodon bidens (Sowerby's beaked whale), (4) Physeter macrocephalus (giant sperm whale), and (5) Kogia breviceps (pygmy sperm whale). All of these cetaceans are known to dive to depths of at least 100 m where the underwater light field is dim and dominated by blue light. The knockout of both SWS1 and LWS in multiple cetacean lineages renders these taxa rod monochromats, a condition previously unknown among mammalian species. PMID:23637615

Meredith, Robert W; Gatesy, John; Emerling, Christopher A; York, Vincent M; Springer, Mark S

2013-04-01

8

Rod Monochromacy and the Coevolution of Cetacean Retinal Opsins  

PubMed Central

Cetaceans have a long history of commitment to a fully aquatic lifestyle that extends back to the Eocene. Extant species have evolved a spectacular array of adaptations in conjunction with their deployment into a diverse array of aquatic habitats. Sensory systems are among those that have experienced radical transformations in the evolutionary history of this clade. In the case of vision, previous studies have demonstrated important changes in the genes encoding rod opsin (RH1), short-wavelength sensitive opsin 1 (SWS1), and long-wavelength sensitive opsin (LWS) in selected cetaceans, but have not examined the full complement of opsin genes across the complete range of cetacean families. Here, we report protein-coding sequences for RH1 and both color opsin genes (SWS1, LWS) from representatives of all extant cetacean families. We examine competing hypotheses pertaining to the timing of blue shifts in RH1 relative to SWS1 inactivation in the early history of Cetacea, and we test the hypothesis that some cetaceans are rod monochomats. Molecular evolutionary analyses contradict the “coastal” hypothesis, wherein SWS1 was pseudogenized in the common ancestor of Cetacea, and instead suggest that RH1 was blue-shifted in the common ancestor of Cetacea before SWS1 was independently knocked out in baleen whales (Mysticeti) and in toothed whales (Odontoceti). Further, molecular evidence implies that LWS was inactivated convergently on at least five occasions in Cetacea: (1) Balaenidae (bowhead and right whales), (2) Balaenopteroidea (rorquals plus gray whale), (3) Mesoplodon bidens (Sowerby's beaked whale), (4) Physeter macrocephalus (giant sperm whale), and (5) Kogia breviceps (pygmy sperm whale). All of these cetaceans are known to dive to depths of at least 100 m where the underwater light field is dim and dominated by blue light. The knockout of both SWS1 and LWS in multiple cetacean lineages renders these taxa rod monochromats, a condition previously unknown among mammalian species. PMID:23637615

Meredith, Robert W.; Gatesy, John; Emerling, Christopher A.; York, Vincent M.; Springer, Mark S.

2013-01-01

9

Potential of fish opsin gene duplications to evolve new functions associated with visual adaptation  

E-print Network

Potential of fish opsin gene duplications to evolve new functions associated with visual adaptation a crucial role in adaptive genome evolution by providing raw materials for functional novelty and LWS) in bony fish, we here provide a clear demonstration that the duplicability is strongly associated

Wehrli, Bernhard

10

Evolution of opsin expression in birds driven by sexual selection and habitat.  

PubMed

Theories of sexual and natural selection predict coevolution of visual perception with conspecific colour and/or the light environment animals occupy. One way to test these theories is to focus on the visual system, which can be achieved by studying the opsin-based visual pigments that mediate vision. Birds vary greatly in colour, but opsin gene coding sequences and associated visual pigment spectral sensitivities are known to be rather invariant across birds. Here, I studied expression of the four cone opsin genes (Lws, Rh2, Sws2 and Sws1) in 16 species of New World warblers (Parulidae). I found levels of opsin expression vary both across species and between the sexes. Across species, female, but not male Sws2 expression is associated with an index of sexual selection, plumage dichromatism. This fits predictions of classic sexual selection models, in which the sensory system changes in females, presumably impacting female preference, and co-evolves with male plumage. Expression of the opsins at the extremes of the light spectrum, Lws and Uvs, correlates with the inferred light environment occupied by the different species. Unlike opsin spectral tuning, regulation of opsin gene expression allows for fast adaptive evolution of the visual system in response to natural and sexual selection, and in particular, sex-specific selection pressures. PMID:25429020

Bloch, Natasha I

2015-01-01

11

RT-qPCR reveals opsin gene upregulation associated with age and sex in guppies (Poecilia reticulata) - a species with color-based sexual selection and 11 visual-opsin genes  

PubMed Central

Background PCR-based surveys have shown that guppies (Poecilia reticulata) have an unusually large visual-opsin gene repertoire. This has led to speculation that opsin duplication and divergence has enhanced the evolution of elaborate male coloration because it improves spectral sensitivity and/or discrimination in females. However, this conjecture on evolutionary connections between opsin repertoire, vision, mate choice, and male coloration was generated with little data on gene expression. Here, we used RT-qPCR to survey visual-opsin gene expression in the eyes of males, females, and juveniles in order to further understand color-based sexual selection from the perspective of the visual system. Results Juvenile and adult (male and female) guppies express 10 visual opsins at varying levels in the eye. Two opsin genes in juveniles, SWS2B and RH2-2, accounted for >85% of all visual-opsin transcripts in the eye, excluding RH1. This relative abundance (RA) value dropped to about 65% in adults, as LWS-A180 expression increased from approximately 3% to 20% RA. The juvenile-to-female transition also showed LWS-S180 upregulation from about 1.5% to 7% RA. Finally, we found that expression in guppies' SWS2-LWS gene cluster is negatively correlated with distance from a candidate locus control region (LCR). Conclusions Selective pressures influencing visual-opsin gene expression appear to differ among age and sex. LWS upregulation in females is implicated in augmenting spectral discrimination of male coloration and courtship displays. In males, enhanced discrimination of carotenoid-rich food and possibly rival males are strong candidate selective pressures driving LWS upregulation. These developmental changes in expression suggest that adults possess better wavelength discrimination than juveniles. Opsin expression within the SWS2-LWS gene cluster appears to be regulated, in part, by a common LCR. Finally, by comparing our RT-qPCR data to MSP data, we were able to propose the first opsin-to-?max assignments for all photoreceptor types in the cone mosaic. PMID:21447186

2011-01-01

12

Molecular and functional characterization of opsins in barfin flounder (Verasper moseri).  

PubMed

Green light irradiation facilitates the somatic growth of barfin flounder (Verasper moseri). However, the V. moseri visual system, which may be associated with somatic growth by acting on the endocrine system upon exposure to this particular wavelength, remains largely unexplored. Herein, we characterized the visual opsin repertoire of V. moseri to understand the molecular basis underlying this effect. The five types of visual opsins that are found in vertebrates were cloned from RNA that was extracted from the eyes of V. moseri. Notably, V. moseri possessed one pseudogene (RH2-A) and two intact (RH2-B and RH2-C) copies of "green-sensitive" opsin genes. The wavelengths of maximum absorption spectra (?max) for each of the reconstituted photopigments were 552nm for "red-sensitive" LWS, 506nm for RH2-B, 490nm for RH2-C, 482nm and 416nm for "blue-sensitive" SWS2A and SWS2B, respectively, 367nm for "ultraviolet-sensitive" SWS1, and 494nm for "dim-light sensitive rhodopsin" RH1. The ?max of SWS2A was longer than that of any other reported vertebrate SWS2 opsin. By measuring the expression level of these opsin genes with quantitative RT-PCR in 3-, 15-, and 27-month-old fish, we found that RH2-B and SWS2A were expressed at a constant level, whereas the expression of LWS, RH2-C, SWS2B, and SWS1 opsin genes decreased, and that of RH1 increased with age. Barfin flounders inhabit inshore waters at a young age and expand their habitat to deep sea areas as they age, and green light is relatively abundant in deep water compared to the lights of other wavelengths in shallow water. Our results indicate that gene repertoire and expression profile of the opsin genes of barfin flounder are adaptive to their habitat shift that occurs during development, with some opsins acquiring a distinct ?max. PMID:25433330

Kasagi, Satoshi; Mizusawa, Kanta; Murakami, Naoto; Andoh, Tadashi; Furufuji, Sumihisa; Kawamura, Shoji; Takahashi, Akiyoshi

2015-02-10

13

Divergence in cis-regulatory sequences surrounding the opsin gene arrays of African cichlid fishes  

PubMed Central

Background Divergence within cis-regulatory sequences may contribute to the adaptive evolution of gene expression, but functional alleles in these regions are difficult to identify without abundant genomic resources. Among African cichlid fishes, the differential expression of seven opsin genes has produced adaptive differences in visual sensitivity. Quantitative genetic analysis suggests that cis-regulatory alleles near the SWS2-LWS opsins may contribute to this variation. Here, we sequence BACs containing the opsin genes of two cichlids, Oreochromis niloticus and Metriaclima zebra. We use phylogenetic footprinting and shadowing to examine divergence in conserved non-coding elements, promoter sequences, and 3'-UTRs surrounding each opsin in search of candidate cis-regulatory sequences that influence cichlid opsin expression. Results We identified 20 conserved non-coding elements surrounding the opsins of cichlids and other teleosts, including one known enhancer and a retinal microRNA. Most conserved elements contained computationally-predicted binding sites that correspond to transcription factors that function in vertebrate opsin expression; O. niloticus and M. zebra were significantly divergent in two of these. Similarly, we found a large number of relevant transcription factor binding sites within each opsin's proximal promoter, and identified five opsins that were considerably divergent in both expression and the number of transcription factor binding sites shared between O. niloticus and M. zebra. We also found several microRNA target sites within the 3'-UTR of each opsin, including two 3'-UTRs that differ significantly between O. niloticus and M. zebra. Finally, we examined interspecific divergence among 18 phenotypically diverse cichlids from Lake Malawi for one conserved non-coding element, two 3'-UTRs, and five opsin proximal promoters. We found that all regions were highly conserved with some evidence of CRX transcription factor binding site turnover. We also found three SNPs within two opsin promoters and one non-coding element that had weak association with cichlid opsin expression. Conclusions This study is the first to systematically search the opsins of cichlids for putative cis-regulatory sequences. Although many putative regulatory regions are highly conserved across a large number of phenotypically diverse cichlids, we found at least nine divergent sequences that could contribute to opsin expression differences in cis and stand out as candidates for future functional analyses. PMID:21554730

2011-01-01

14

The NASA LWS Sentinels Mission  

NASA Astrophysics Data System (ADS)

One of the primary goals of NASA's Sentinels mission, the heliospheric element of the integrated LWS (Living With a Star) program, is to provide the observations necessary for an understanding of the physics of the Sun/inner heliosphere processes that produce Solar Energetic Particle (SEP) events, so the requirements for eventual predictive capability can be defined. We present the results of the study by the Sentinels Science and Technology Definition Team (STDT) that recommends a combination of the Inner Heliosphere Sentinels (IHS),consisting of four identical spacecraft that utilize Venus gravity assists to achieve 0.25-0.75 AU orbits, primarily for in situ particles and fields measurements; a Near-Earth Sentinel (NES) with a spectroscopic coronagraph to provide the physical conditions in the SEP acceleration region and a wide field (>0.3AU) coronagraph to connect to the HIS measurements, and a Farside Sentinel (FS) with a magnetograph to provide near global photospheric magnetic field measurements for modeling the structure of the inner heliosphere. We show how the combined measurements are designed to lead to an understanding of SEP origin and to improve our predictive capability for large SEP events.

Lin, Robert P.; Science, Sentinels; DefinitionTeam, Technology

2006-06-01

15

Correlation between nuptial colors and visual sensitivities tuned by opsins leads to species richness in sympatric Lake Victoria cichlid fishes.  

PubMed

Reproductive isolation that prevents interspecific hybridization between closely related coexisting species maintains sympatric species diversity. One of the reproductive isolations is mate choice based on color signals (breeding color perceived by color vision). This is well known in several animal taxa, yet little is known about its genetic and molecular mechanism. Lake Victoria cichlid fishes are thought to be an example of sympatric species diversity. In the species inhabiting different light environments in rocky shore, speciation by sensory drive through color signals has been proposed by analyses of the long wavelength-sensitive (LWS) opsin gene and the male nuptial coloration. However, the genetic and molecular mechanism of how diversity of sympatric species occurring in the same habitat is maintained remains unknown. To address this issue, we determined nucleotide sequences of eight opsins of six sympatric species collected from a sandy-muddy shore--an ideal model system for studying sympatric species. Among eight opsins, the LWS and RH1 alleles were diversified and one particular allele is dominant or fixed in each species, and we propose that this is due to natural selection. The functions of their LWS alleles were also diversified as shown by absorption measurements of reconstituted visual pigments. To analyze the relationship between nuptial coloration and the absorption of LWS pigments, we systematically evaluated and defined nuptial coloration. We showed that the coloration was species specific with respect to hue and significantly differentiated by the index values of hue (dominant wavelength: ?(d)). The ?(d) value of the male nuptial coloration correlated with the absorption of LWS pigments from all the species, suggesting that reproductive isolation through mate choice using color signals may prevent sympatric interspecific hybridization, thereby maintaining the species diversity in sympatric species in Lake Victoria. PMID:22617953

Miyagi, Ryutaro; Terai, Yohey; Aibara, Mitsuto; Sugawara, Tohru; Imai, Hiroo; Tachida, Hidenori; Mzighani, Semvua Isa; Okitsu, Takashi; Wada, Akimori; Okada, Norihiro

2012-11-01

16

Evolution and functional diversity of jellyfish opsins.  

PubMed

Cnidaria are the most basal animal phylum possessing complex eyes [1]. Their eyes predominantly use ciliary photoreceptor cells (c-PRCs) like vertebrates, whereas insect eyes use rhabdomeric photoreceptor cells (r-PRCs) [1-4]. These two cell types show not only different cytoarchitectures but distinct phototransduction cascades, which are triggered by the respective types of opsins (e.g., [5]), ciliary opsins (c-opsins) and rhabdomeric opsins (r-opsins) [6]. Recent reports suggested that the c- and r-PRCs and their respective opsins diverged at least before the deuterostome-protostome split [7-9]. To study the earlier evolution of animal PRCs and opsins, we investigated two hydrozoan jellyfishes. We report here the first-characterized cnidarian opsins. Molecular phylogeny revealed that the cloned 20 jellyfish opsins, together with all the opsins from a hydra and some from a sea anemone, are more closely related to the c-opsins than to any other major opsin subfamily, indicating that the divergence of c- and r-opsins antedates the Cnidaria-Bilateria split. Possible scenarios of animal PRC evolution are discussed. Furthermore, Cladonema opsins show several distinct tissue- and stage-specific expression patterns. The expression of specific opsins in the eyes suggests a role in vision, whereas that in the gonads suggests a role in light-controlled release of gametes. PMID:18160295

Suga, Hiroshi; Schmid, Volker; Gehring, Walter J

2008-01-01

17

SWS and LWS observations of Cassiopeia A  

NASA Technical Reports Server (NTRS)

The observations of the Casssiopeia A supernova remnant performed with the short wavelength spectrometer (SWS) and the long wavelength spectrometer (LWS), onboard the Infrared Space Observatory (ISO), are reported on. Broad O III 52 micrometer and 88 micrometer and O I 63 micrometer emission lines were detected. The far infrared O III lines fit the model of a spherical shell with central velocity redshifted by 770 +/- 40 km/s. A pronounced density contrast between the front and back of the shell was detected.

Unger, S. J.; Pequignot, D.; Cox, P.; Haas, M. R.; Baluteau, J. P.; Lahuis, F.; Emery, R. J.; Morisset, C.

1997-01-01

18

Opsin vs opsin: New materials for biotechnological applications  

NASA Astrophysics Data System (ADS)

The need of new diagnostic methods satisfying, as an early detection, a low invasive procedure and a cost-efficient value, is orienting the technological research toward the use of bio-integrated devices, in particular, bio-sensors. The set of know-why necessary to achieve this goal is wide, from biochemistry to electronics and is summarized in an emerging branch of electronics, called proteotronics. Proteotronics is here applied to state a comparative analysis of the electrical responses coming from type-1 and type-2 opsins. In particular, the procedure is used as an early investigation of a recently discovered family of opsins, the proteorhodopsins activated by blue light, BPRs. The results reveal some interesting and unexpected similarities between proteins of the two families, suggesting the global electrical response are not strictly linked to the class identity.

Alfinito, Eleonora; Reggiani, Lino

2014-08-01

19

Opsin vs opsin: new materials for biotechnological applications  

E-print Network

The need of new diagnostic methods satisfying, as an early detection, a low invasive procedure and a cost-efficient value, is orienting the technological research toward the use of bio-integrated devices, in particular bio-sensors. The set of know-why necessary to achieve this goal is wide, from biochemistry to electronics and is summarized in an emerging branch of electronics, called \\textit{proteotronics}. Proteotronics is here here applied to state a comparative analysis of the electrical responses coming from type-1 and type-2 opsins. In particular, the procedure is used as an early investigation of a recently discovered family of opsins, the proteorhodopsins activated by blue light, BPRs. The results reveal some interesting and unexpected similarities between proteins of the two families, suggesting the global electrical response are not strictly linked to the class identity.

E. Alfinito; L. Reggiani

2014-08-09

20

LWS/SET Technology Experiment Carrier  

NASA Technical Reports Server (NTRS)

This paper examines the approach taken to building a low-cost, modular spacecraft bus that can be used to support a variety of technology experiments in different space environments. It describes the techniques used and design drivers considered to ensure experiment independence from as yet selected host spacecraft. It describes the technology experiment carriers that will support NASA's Living With a Star Space Environment Testbed space missions. NASA has initiated the Living With a Star (LWS) Program to develop a better scientific understanding to address the aspects of the connected Sun-Earth system that affect life and society. A principal goal of the program is to bridge the gap between science, engineering, and user application communities. The Space Environment Testbed (SET) Project is one element of LWS. The Project will enable future science, operational, and commercial objectives in space and atmospheric environments by improving engineering approaches to the accommodation and/or mitigation of the effects of solar variability on technological systems. The SET Project is highly budget constrained and must seek to take advantage of as yet undetermined partnering opportunities for access to space. SET will conduct technology validation experiments hosted on available flight opportunities. The SET Testbeds will be developed in a manner that minimizes the requirements for accommodation, and will be flown as flight opportunities become available. To access the widest range of flight opportunities, two key development requirements are to maintain flexibility with respect to accommodation constraints and to have the capability to respond quickly to flight opportunities. Experiments, already developed to the technology readiness level of needing flight validation in the variable Sun-Earth environment, will be selected on the basis of the need for the subject technology, readiness for flight, need for flight resources and particular orbit. Experiments will be accumulated by the Project and manifested for specific flight opportunities as they become available. The SET Carrier is designed to present a standard set of interfaces to SET technology experiments and to be modular and flexible enough to interface to a variety of possible host spacecraft. The Carrier will have core components and mission unique components. Once the core carrier elements have been developed, only the mission unique components need to be defined and developed for any particular mission. This approach will minimize the mission specific cost and development schedule for a given flight opportunity. The standard set of interfaces provided by SET to experiments allows them to be developed independent of the particulars of a host spacecraft. The Carrier will provide the power, communication, and the necessary monitoring features to operate experiments. The Carrier will also provide all of the mechanical assemblies and harnesses required to adapt experiments to a particular host. Experiments may be hosted locally with the Carrier or remotely on the host spacecraft. The Carrier design will allow a single Carrier to support a variable number of experiments and will include features that support the ability to incrementally add experiments without disturbing the core architecture.

Sherman, Barry; Giffin, Geoff

2002-01-01

21

Shedding new light on opsin evolution  

PubMed Central

Opsin proteins are essential molecules in mediating the ability of animals to detect and use light for diverse biological functions. Therefore, understanding the evolutionary history of opsins is key to understanding the evolution of light detection and photoreception in animals. As genomic data have appeared and rapidly expanded in quantity, it has become possible to analyse opsins that functionally and histologically are less well characterized, and thus to examine opsin evolution strictly from a genetic perspective. We have incorporated these new data into a large-scale, genome-based analysis of opsin evolution. We use an extensive phylogeny of currently known opsin sequence diversity as a foundation for examining the evolutionary distributions of key functional features within the opsin clade. This new analysis illustrates the lability of opsin protein-expression patterns, site-specific functionality (i.e. counterion position) and G-protein binding interactions. Further, it demonstrates the limitations of current model organisms, and highlights the need for further characterization of many of the opsin sequence groups with unknown function. PMID:22012981

Porter, Megan L.; Blasic, Joseph R.; Bok, Michael J.; Cameron, Evan G.; Pringle, Thomas; Cronin, Thomas W.; Robinson, Phyllis R.

2012-01-01

22

Analysis of the opsin repertoire in the tardigrade Hypsibius dujardini provides insights into the evolution of opsin genes in panarthropoda.  

PubMed

Screening of a deeply sequenced transcriptome using Illumina sequencing as well as the genome of the tardigrade Hypsibius dujardini revealed a set of five opsin genes. To clarify the phylogenetic position of these genes and to elucidate the evolutionary history of opsins in Panarthropoda (Onychophora + Tardigrada + Arthropoda), we reconstructed the phylogeny of broadly sampled metazoan opsin genes using maximum likelihood and Bayesian inference methods in conjunction with carefully selected substitution models. According to our findings, the opsin repertoire of H. dujardini comprises representatives of all three major bilaterian opsin clades, including one r-opsin, three c-opsins, and a Group 4 opsin (neuropsin/opsin-5). The identification of the tardigrade ortholog of neuropsin/opsin-5 is the first record of this opsin type in a protostome, but our screening of available metazoan genomes revealed that it is also present in other protostomes. Our opsin phylogeny further suggests that two r-opsins, including an "arthropsin," were present in the last common ancestor of Panarthropoda. Although both r-opsin lineages were retained in Onychophora and Arthropoda, the arthropsin was lost in Tardigrada. The single (most likely visual) r-opsin found in H. dujardini supports the hypothesis of monochromatic vision in the panarthropod ancestor, whereas two duplications of the ancestral panarthropod c-opsin have led to three c-opsins in tardigrades. Although the early-branching nodes are unstable within the metazoans, our findings suggest that the last common ancestor of Bilateria possessed six opsins: Two r-opsins, one c-opsin, and three Group 4 opsins, one of which (Go opsin) was lost in the ecdysozoan lineage. PMID:25193307

Hering, Lars; Mayer, Georg

2014-09-01

23

Leading Edge The Microbial Opsin Family  

E-print Network

Leading Edge Primer The Microbial Opsin Family of Optogenetic Tools Feng Zhang,1,2,9,* Johannes advances in understanding microbial opsins have been driven by molecular engineering for optogenetics on these and other light-sensitive proteins has resulted in a technology called optogenetics (Deisseroth, 2011

Schnitzer, Mark

24

The Microbial Opsin Family of Optogenetic Tools  

Microsoft Academic Search

The capture and utilization of light is an exquisitely evolved process. The single-component microbial opsins, although more limited than multicomponent cascades in processing, display unparalleled compactness and speed. Recent advances in understanding microbial opsins have been driven by molecular engineering for optogenetics and by comparative genomics. Here we provide a Primer on these light-activated ion channels and pumps, describe a

Feng Zhang; Johannes Vierock; Ofer Yizhar; Lief E. Fenno; Satoshi Tsunoda; Arash Kianianmomeni; Matthias Prigge; Andre Berndt; John C. Cushman; Juergen E. Polle; Jon K. Magnuson; Peter Hegemann; Karl Deisseroth

2011-01-01

25

S-opsin knockout mice with the endogenous M opsin gene replaced by an L opsin variant  

PubMed Central

Specific variants of human long-wavelength (L) and middle-wavelength (M) cone opsin genes have recently been associated with a variety of vision disorders caused by cone malfunction, including red-green color vision deficiency, blue cone monochromacy, myopia, and cone dystrophy. Strikingly, unlike disease-causing mutations in rhodopsin, most of the cone opsin alleles that are associated with vision disorders do not have deleterious point mutations. Instead, specific combinations of normal polymorphisms that arose by genetic recombination between the genes encoding L and M opsins appear to cause disease. Knockout/knock-in mice promise to make it possible to study how these deleterious cone opsin variants affect the structure, function, and viability of the cone photoreceptors. Ideally, we would like to evaluate different variants that cause vision disorders in humans against a control pigment that is not associated with vision disorders, and each variant should be expressed as the sole photopigment in each mouse cone, as is the case in humans. To evaluate the feasibility of this approach, we created a line of mice to serve as the control in the analysis of disease causing mutations by replacing exon 2 through 6 of the mouse M opsin gene with the corresponding cDNA for a human L opsin variant that is associated with normal vision. Experiments reported here establish that the resulting pigment, which differs from the endogenous mouse M opsin at 35 amino acid positions, functions normally in mouse cones. This pigment was evaluated in mice with and without co-expression of the mouse short wavelength (S) opsin. Here, the creation and validation of two lines of genetically engineered mice that can be used to study disease-causing variants of human L/M-opsins, in vivo, are described. PMID:24801621

Greenwald, Scott H.; Kuchenbecker, James A.; Roberson, Daniel K.; Neitz, Maureen; Neitz, Jay

2014-01-01

26

The Microbial Opsin Family of Optogenetic Tools  

SciTech Connect

The capture and utilization of light is an exquisitely evolved process. The single-component microbial opsins, although more limited than multicomponent cascades in processing, display unparalleled compactness and speed. Recent advances in understanding microbial opsins have been driven by molecular engineering for optogenetics and by comparative genomics. Here we provide a Primer on these light-activated ion channels and pumps, describe a group of opsins bridging prior categories, and explore the convergence of molecular engineering and genomic discovery for the utilization and understanding of these remarkable molecular machines.

Zhang, Feng; Vierock, Johannes; Yizhar, Ofer; Fenno, Lief E.; Tsunoda, Satoshi; Kianianmomeni, Arash; Prigge, Matthias; Berndt, Andre; Cushman, John C.; Polle, Juergen E.; Magnuson, Jon K.; Hegemann, Peter; Deisseroth, Karl

2011-12-23

27

The Microbial Opsin Family of Optogenetic Tools  

PubMed Central

The capture and utilization of light is an exquisitely evolved process. The single-component microbial opsins, although more limited than multicomponent cascades in processing, display unparalleled compactness and speed. Recent advances in understanding microbial opsins have been driven by molecular engineering for optogenetics and by comparative genomics. Here we provide a Primer on these light-activated ion channels and pumps, describe a group of opsins bridging prior categories, and explore the convergence of molecular engineering and genomic discovery for the utilization and understanding of these remarkable molecular machines. PMID:22196724

Zhang, Feng; Vierock, Johannes; Yizhar, Ofer; Fenno, Lief E.; Tsunoda, Satoshi; Kianianmomeni, Arash; Prigge, Matthias; Berndt, Andre; Cushman, John; Polle, Jürgen; Magnuson, Jon; Hegemann, Peter; Deisseroth, Karl

2014-01-01

28

Metazoan opsin evolution reveals a simple route to animal vision.  

PubMed

All known visual pigments in Neuralia (Cnidaria, Ctenophora, and Bilateria) are composed of an opsin (a seven-transmembrane G protein-coupled receptor), and a light-sensitive chromophore, generally retinal. Accordingly, opsins play a key role in vision. There is no agreement on the relationships of the neuralian opsin subfamilies, and clarifying their phylogeny is key to elucidating the origin of this protein family and of vision. We used improved methods and data to resolve the opsin phylogeny and explain the evolution of animal vision. We found that the Placozoa have opsins, and that the opsins share a common ancestor with the melatonin receptors. Further to this, we found that all known neuralian opsins can be classified into the same three subfamilies into which the bilaterian opsins are classified: the ciliary (C), rhabdomeric (R), and go-coupled plus retinochrome, retinal G protein-coupled receptor (Go/RGR) opsins. Our results entail a simple scenario of opsin evolution. The first opsin originated from the duplication of the common ancestor of the melatonin and opsin genes in a eumetazoan (Placozoa plus Neuralia) ancestor, and an inference of its amino acid sequence suggests that this protein might not have been light-sensitive. Two more gene duplications in the ancestral neuralian lineage resulted in the origin of the R, C, and Go/RGR opsins. Accordingly, the first animal with at least a C, an R, and a Go/RGR opsin was a neuralian progenitor. PMID:23112152

Feuda, Roberto; Hamilton, Sinead C; McInerney, James O; Pisani, Davide

2012-11-13

29

Metazoan opsin evolution reveals a simple route to animal vision  

PubMed Central

All known visual pigments in Neuralia (Cnidaria, Ctenophora, and Bilateria) are composed of an opsin (a seven-transmembrane G protein-coupled receptor), and a light-sensitive chromophore, generally retinal. Accordingly, opsins play a key role in vision. There is no agreement on the relationships of the neuralian opsin subfamilies, and clarifying their phylogeny is key to elucidating the origin of this protein family and of vision. We used improved methods and data to resolve the opsin phylogeny and explain the evolution of animal vision. We found that the Placozoa have opsins, and that the opsins share a common ancestor with the melatonin receptors. Further to this, we found that all known neuralian opsins can be classified into the same three subfamilies into which the bilaterian opsins are classified: the ciliary (C), rhabdomeric (R), and go-coupled plus retinochrome, retinal G protein-coupled receptor (Go/RGR) opsins. Our results entail a simple scenario of opsin evolution. The first opsin originated from the duplication of the common ancestor of the melatonin and opsin genes in a eumetazoan (Placozoa plus Neuralia) ancestor, and an inference of its amino acid sequence suggests that this protein might not have been light-sensitive. Two more gene duplications in the ancestral neuralian lineage resulted in the origin of the R, C, and Go/RGR opsins. Accordingly, the first animal with at least a C, an R, and a Go/RGR opsin was a neuralian progenitor. PMID:23112152

Feuda, Roberto; Hamilton, Sinead C.; McInerney, James O.; Pisani, Davide

2012-01-01

30

The comb jelly opsins and the origins of animal phototransduction.  

PubMed

Opsins mediate light detection in most animals, and understanding their evolution is key to clarify the origin of vision. Despite the public availability of a substantial collection of well-characterized opsins, early opsin evolution has yet to be fully understood, in large part because of the high level of divergence observed among opsins belonging to different subfamilies. As a result, different studies have investigated deep opsin evolution using alternative data sets and reached contradictory results. Here, we integrated the data and methods of three, key, recent studies to further clarify opsin evolution. We show that the opsin relationships are sensitive to outgroup choice; we generate new support for the existence of Rhabdomeric opsins in Cnidaria (e.g., corals and jellyfishes) and show that all comb jelly opsins belong to well-recognized opsin groups (the Go-coupled opsins or the Ciliary opsins), which are also known in Bilateria (e.g., humans, fruit flies, snails, and their allies) and Cnidaria. Our results are most parsimoniously interpreted assuming a traditional animal phylogeny where Ctenophora are not the sister group of all the other animals. PMID:25062921

Feuda, Roberto; Rota-Stabelli, Omar; Oakley, Todd H; Pisani, Davide

2014-08-01

31

Opsin Expression in Human Epidermal Skin  

PubMed Central

Human skin is constantly exposed to solar light containing visible and ultraviolet radiation (UVR), a powerful skin carcinogen. UVR elicits cellular responses in epidermal cells via several mechanisms: direct absorption of short-wavelength UVR photons by DNA, oxidative damage caused by long-wavelength UVR, and, as we recently demonstrated, via a retinal-dependent G protein-coupled signaling pathway. Because the human epidermis is exposed to a wide range of light wavelengths, we investigated whether opsins, light-activated receptors that mediate photoreception in the eye, are expressed in epidermal skin to potentially serve as photosensors. Here we show that four opsins—OPN1-SW, OPN2, OPN3 and OPN5—are expressed in the two major human epidermal cell types, melanocytes and keratinocytes, and the mRNA expression profile of these opsins does not change in response to physiological UVR doses. We detected two OPN3 splice variants present in similar amounts in both cell types and three OPN5 splice isoforms, two of which encode truncated proteins. Notably, OPN2 and OPN3 mRNA were significantly more abundant than other opsins and encoded full-length proteins. Our results demonstrate that opsins are expressed in epidermal skin cells and suggest that they might initiate light–induced signaling pathways, possibly contributing to UVR phototransduction. PMID:25267311

Haltaufderhyde, Kirk; Ozdeslik, Rana N; Wicks, Nadine L; Najera, Julia A; Oancea, Elena

2015-01-01

32

A mammalian neural tissue opsin (Opsin 5) is a deep brain photoreceptor in birds  

PubMed Central

It has been known for many decades that nonmammalian vertebrates detect light by deep brain photoreceptors that lie outside the retina and pineal organ to regulate seasonal cycle of reproduction. However, the identity of these photoreceptors has so far remained unclear. Here we report that Opsin 5 is a deep brain photoreceptive molecule in the quail brain. Expression analysis of members of the opsin superfamily identified as Opsin 5 (OPN5; also known as Gpr136, Neuropsin, PGR12, and TMEM13) mRNA in the paraventricular organ (PVO), an area long believed to be capable of phototransduction. Immunohistochemistry identified Opsin 5 in neurons that contact the cerebrospinal fluid in the PVO, as well as fibers extending to the external zone of the median eminence adjacent to the pars tuberalis of the pituitary gland, which translates photoperiodic information into neuroendocrine responses. Heterologous expression of Opsin 5 in Xenopus oocytes resulted in light-dependent activation of membrane currents, the action spectrum of which showed peak sensitivity (?max) at ?420 nm. We also found that short-wavelength light, i.e., between UV-B and blue light, induced photoperiodic responses in eye-patched, pinealectomized quail. Thus, Opsin 5 appears to be one of the deep brain photoreceptive molecules that regulates seasonal reproduction in birds. PMID:20679218

Nakane, Yusuke; Ikegami, Keisuke; Ono, Hiroko; Yamamoto, Naoyuki; Yoshida, Shosei; Hirunagi, Kanjun; Ebihara, Shizufumi; Kubo, Yoshihiro; Yoshimura, Takashi

2010-01-01

33

LWS/SET End-to-End Data System  

NASA Technical Reports Server (NTRS)

This paper describes the concept for the End-to-End Data System that will support NASA's Living With a Star Space Environment Testbed missions. NASA has initiated the Living With a Star (LWS) Program to develop a better scientific understanding to address the aspects of the connected Sun-Earth system that affect life and society. A principal goal of the program is to bridge the gap.between science, engineering, and user application communities. The Space Environment Testbed (SET) Project is one element of LWS. The Project will enable future science, operational, and commercial objectives in space and atmospheric environments by improving engineering approaches to the accommodation and/or mitigation of the effects of solar variability on technological systems. The End-to-end data system allows investigators to access the SET control center, command their experiments, and receive data from their experiments back at their home facility, using the Internet. The logical functioning of major components of the end-to-end data system are described, including the GSFC Payload Operations Control Center (POCC), SET Payloads, the GSFC SET Simulation Lab, SET Experiment PI Facilities, and Host Systems. Host Spacecraft Operations Control Centers (SOCC) and the Host Spacecraft are essential links in the end-to-end data system, but are not directly under the control of the SET Project. Formal interfaces will be established between these entities and elements of the SET Project. The paper describes data flow through the system, from PI facilities connecting to the SET operations center via the Internet, communications to SET carriers and experiments via host systems, to telemetry returns to investigators from their flight experiments. It also outlines the techniques that will be used to meet mission requirements, while holding development and operational costs to a minimum. Additional information is included in the original extended abstract.

Giffin, Geoff; Sherman, Barry; Colon, Gilberto (Technical Monitor)

2002-01-01

34

Opsin clines in butterflies suggest novel roles for insect photopigments.  

PubMed

Opsins are ancient molecules that enable animal vision by coupling to a vitamin-derived chromophore to form light-sensitive photopigments. The primary drivers of evolutionary diversification in opsins are thought to be visual tasks related to spectral sensitivity and color vision. Typically, only a few opsin amino acid sites affect photopigment spectral sensitivity. We show that opsin genes of the North American butterfly Limenitis arthemis have diversified along a latitudinal cline, consistent with natural selection due to environmental factors. We sequenced single nucleotide (SNP) polymorphisms in the coding regions of the ultraviolet (UVRh), blue (BRh), and long-wavelength (LWRh) opsin genes from ten butterfly populations along the eastern United States and found that a majority of opsin SNPs showed significant clinal variation. Outlier detection and analysis of molecular variance indicated that many SNPs are under balancing selection and show significant population structure. This contrasts with what we found by analysing SNPs in the wingless and EF-1 alpha loci, and from neutral amplified fragment length polymorphisms, which show no evidence of significant locus-specific or genome-wide structure among populations. Using a combination of functional genetic and physiological approaches, including expression in cell culture, transgenic Drosophila, UV-visible spectroscopy, and optophysiology, we show that key BRh opsin SNPs that vary clinally have almost no effect on spectral sensitivity. Our results suggest that opsin diversification in this butterfly is more consistent with natural selection unrelated to spectral tuning. Some of the clinally varying SNPs may instead play a role in regulating opsin gene expression levels or the thermostability of the opsin protein. Lastly, we discuss the possibility that insect opsins might have important, yet-to-be elucidated, adaptive functions in mediating animal responses to abiotic factors, such as temperature or photoperiod. PMID:25371434

Frentiu, Francesca D; Yuan, Furong; Savage, Wesley K; Bernard, Gary D; Mullen, Sean P; Briscoe, Adriana D

2015-02-01

35

Keck LWS Mid-IR Observations of Nearby LLAGN  

NASA Astrophysics Data System (ADS)

We present new Keck LWS Mid-IR (MIR) imaging observations of a sample of LLAGN. Our results show that nuclear 10 micron fluxes of NGC4203 and NGC4736, along with three other LLGN from previous work, correlate with X-ray flux with the same relation as more luminous Seyferts and quasars. The nuclear emission of our objects is clearly differentiated from that of starburst activity on a plot of MIR vs. X-ray flux. Because X-ray and MIR fluxes are nearly insensitive to dust extinction, this behavior suggests the same continuum origin for our LLAGN sample as for Seyferts. MIR images of the nucleus of M81 show clearly extended, elliptical structure roughly 3.5" across the long axis ( 70 pc at the source), confirming earlier, lower resolution measurements at Palomar. This structure, the relative MIR and X-ray nuclear fluxes, the lack of stellar emission sufficient to power the MIR flux, and a weak UV continuum, are evidence for material within the nucleus extinguishing an AGN which powers the MIR emission. A unified model torus may be the origin of the extinction. The author gratefully acknowledges the support of the American Astronomical Society and the LBNL Institute for Nuclear and Particle Astrophysics (INPA) for this work.

Grossan, B.

2002-12-01

36

Living with a Star (LWS) Space Environment Testbeds (SET), Mission Carrier Overview and Capabilities  

NASA Technical Reports Server (NTRS)

NASA has initiated the Living With a Star (LWS) Program to develop the scientific understanding to address the aspects of the Connected Sun-Earth system that affect life and society. A goal of the program is to bridge the gap between science, engineering, and user application communities. This will enable future science, operational, and commercial objectives in space and atmospheric environments by improving engineering approaches to the accommodation and/or mitigation of the effects of solar variability on technological systems. The three program elements of the LWS Program are Science Missions; Targeted Research and Technology; and Space Environment Testbeds (SETS). SET is an ideal platform for small experiments performing research on space environment effects on technologies and on the mitigation of space weather effects. A short description of the LWS Program will be given, and the SET will be described in detail, giving the mission objectives, available carrier services, and upcoming flight opportunities.

Patschke, Robert; Barth, Janet; Label, Ken; Mariano, Carolyn; Pham, Karen; Brewer, Dana; Cuviello, Michael; Kobe, David; Wu, Carl; Jarosz, Donald

2004-01-01

37

Leading Edge Primer The Microbial Opsin Family of Optogenetic Tools  

E-print Network

The capture and utilization of light is an exquisitely evolved process. The single-component microbial opsins, although more limited than multicomponent cascades in processing, display unparalleled compactness and speed. Recent advances in understanding microbial opsins have been driven by molecular engineering for optogenetics and by comparative genomics. Here we provide a Primer on these light-activated ion channels and pumps, describe a group of opsins bridging prior categories, and explore the convergence of molecular engineering and genomic discovery for the utilization and understanding of these remarkable molecular machines.

Feng Zhang; Johannes Vierock; Ofer Yizhar; Lief E. Fenno; Satoshi Tsunoda; Arash Kianianmomeni; Matthias Prigge; Andre Berndt; John Cushman; Jürgen Polle; Jon Magnuson; Peter Hegemann

38

Far infrared spectroscopy of FU Ori objects. ISO-LWS observations  

Microsoft Academic Search

We present the results of the first spectrophotometric observations of a sample of FU Ori objects obtained with the Long Wavelength Spectrometer (LWS) on board the Infrared Space Observatory (ISO). The [OI] (63 mu m) and the [CII] (158 mu m) lines are commonly observed in all spectra (both ON and OFF source). The observational novelty is the presence in

D. Lorenzetti; T. Giannini; B. Nisini; M. Benedettini; M. Creech-Eakman; G. A. Blake; E. F. van Dishoeck; M. Cohen; R. Liseau; S. Molinari; S. Pezzuto; P. Saraceno; H. A. Smith; L. Spinoglio; G. J. White

2000-01-01

39

Photoionization modeling of the LWS fine-structure lines in IR bright galaxies  

NASA Technical Reports Server (NTRS)

The long wavelength spectrometer (LWS) fine structure line spectra from infrared luminous galaxies were modeled using stellar evolutionary synthesis models combined with photoionization and photodissociation region models. The calculations were carried out by using the computational code CLOUDY. Starburst and active galactic nuclei models are presented. The effects of dust in the ionized region are examined.

Satyapal, S.; Luhman, M. L.; Fischer, J.; Greenhouse, M. A.; Wolfire, M. G.

1997-01-01

40

Honeybee Blue-and Ultraviolet-Sensitive Opsins: Cloning, Heterologous Expression in Drosophila, and  

E-print Network

­6 photoreceptor cells of blind ninaE mutant Drosophila, which lack the major opsin of the fly compound eye. We-sensitive opsin; electro- retinogram; protein expression; Drosophila melanogaster Color vision is one of the mostHoneybee Blue- and Ultraviolet-Sensitive Opsins: Cloning, Heterologous Expression in Drosophila

Pierce, Naomi E.

41

Opsin gene polymorphism predicts trichromacy in a cathemeral lemur.  

PubMed

Recent research has identified polymorphic trichromacy in three diurnal strepsirrhines: Coquerel's sifaka (Propithecus coquereli), black and white ruffed lemurs (Varecia variegata), and red ruffed lemurs (V. rubra). Current hypotheses suggest that the transitions to diurnality experienced by Propithecus and Varecia were necessary precursors to their independent acquisitions of trichromacy. Accordingly, cathemeral lemurs are thought to lack the M/L opsin gene polymorphism necessary for trichromacy. In this study, the M/L opsin gene was sequenced in ten cathemeral blue-eyed black lemurs (Eulemur macaco flavifrons). This analysis identified a polymorphism identical to that of other trichromatic strepsirrhines at the critical amino acid position 285 in exon 5 of the M/L opsin gene. Thus, polymorphic trichromacy is likely present in at least one cathemeral Eulemur species, suggesting that strict diurnality is not necessary for trichromacy. The presence of trichromacy in E. m. flavifrons suggests that a re-evaluation of current hypotheses regarding the evolution of strepsirrhine trichromacy may be necessary. Although the M/L opsin polymorphism may have been independently acquired three times in the lemurid-indriid clade, the distribution of opsin alleles in lemurids and indriids may also be consistent with a common origin of trichromacy in the last common ancestor of either the lemurids or the lemurid-indriid clade. PMID:18837042

Veilleux, Carrie C; Bolnick, Deborah A

2009-01-01

42

Probing Human Red Cone Opsin Activity with Retinal Analogues?  

PubMed Central

Retinal analogues have been used to probe the chromophore binding pocket and function of the rod visual pigment, rhodopsin. Despite the high homology between rod and cone visual pigment proteins, conclusions drawn from rhodopsin studies should not necessarily be extrapolated to cone visual pigment proteins. In this study, the effects of full-length and truncated retinal analogues on the human red cone opsin’s ability to activate transducin, the G protein in visual transduction, were assessed. The result with beta-ionone (6) confirms that a covalent bond is not necessary to deactivate the red cone opsin. In addition, several small compounds were found able to deactivate this opsin. However, as the polyene chain is extended in a trans configuration beyond the 9-carbon position, the analogues became agonists up to all-trans-retinal (3). The 22-carbon analogue (2) appeared to be neither agonist nor inverse agonist. Although the all-trans-C17 (5) analogue was an agonist, the 9-cis-C17 (11) compound was an inverse agonist, a result that differs from that with rhodopsin. These results suggest that the red cone opsin has a more open structure in the chromophore binding region than rhodopsin and its activation or deactivation as a G-protein receptor may be less selective than rhodopsin. PMID:21314100

Kono, Masahiro; Crouch, Rosalie K.

2011-01-01

43

Parallel evolution of opsin gene expression in African cichlid fishes.  

PubMed

Phenotypic evolution may occur either through alterations to the structure of protein-coding genes or their expression. Evidence for which of these two mechanisms more commonly contribute to the evolution of a phenotype can be garnered from examples of parallel and convergent evolution. The visual system of East African cichlid fishes is an excellent system with which to address this question. Cichlid fishes from Lakes Malawi (LM) and Victoria together exhibit three diverse palettes of coexpressed opsins and several important protein-coding mutations that both shift spectral sensitivity. Here we assess both opsin expression and protein-coding diversity among cichlids from a third rift lake, Lake Tanganyika (LT). We found that Tanganyikan cichlids exhibit three palettes of coexpressed opsins that largely overlap the short-, middle-, and long-wavelength-sensitive palettes of LM cichlids. Bayesian phenotypic clustering and ancestral state reconstructions both support the parallel evolution of the short- and middle-wavelength palettes among cichlids from LT and LM. In each case, these transitions occurred from different ancestors that expressed the same long-wavelength palette. We also identified similar but distinct patterns of correlated evolution between opsin expression, diet, and lens transmittance among cichlids from LT and LM as well. In contrast to regulatory changes, we identified few functional or potentially functional mutations in the protein-coding sequences of three variable opsins, with the possible exception of the SWS1 (ultraviolet) opsin. These results underscore the important contribution that gene regulation can make to rapid phenotypic evolution and adaptation. PMID:20601410

O'Quin, Kelly E; Hofmann, Christopher M; Hofmann, Hans A; Carleton, Karen L

2010-12-01

44

Far-infrared Spectroscopy of Normal Galaxies with ISO-LWS: Physical conditions in the ISM  

Microsoft Academic Search

We report observations of atomic fine structure lines in 45 normal galaxies with the Long Wavelength Spectrograph (LWS) on the Infrared Space Observatory (ISO). These observations are a part of US-ISO Key project to characterize the ISM and star-formation in normal star-forming galaxies spanning a range of morphologies (E-Irr), infrared luminosities, far-infrared colors and far-infrared to blue luminosity. Up to

S. Malhotra; S. D. Lord; G. Helou; C. Beichman; H. L. Dinerstein; D. J. Hollenbach; D. A. Hunter; K. Y. Lo; N. Y. Lu; R. H. Rubin; N. Silbermann; G. Stacey; H. A. Thronson Jr.; M. W. Werner

1997-01-01

45

Implications of the ISO LWS spectrum of the prototypical ultraluminous galaxy: ARP 220  

NASA Technical Reports Server (NTRS)

The low resolution far infrared spectrum of the galaxy Arp 220, obtained with the low wavelength spectrometer (LWS) onboard the Infrared Space Observatory (ISO), is presented. The spectrum is dominated by the OH, H2O, CH, NH3 and O I absorption lines. The upper limits on the far infrared fine structure lines indicate a softer radiation in Arp 220 than in starburst galaxies.

Fischer, J.; Satyapal, S.; Luhman, M. L.; Melnick, G.; Cox, P.; Cernicharo, J.; Stacey, G. J.; Smith, H. A.; Lord, S. D.; Greenhouse, M. A.

1997-01-01

46

An S-opsin knockin mouse (F81Y) reveals a role for the native ligand 11-cis retinal in cone opsin biosynthesis  

PubMed Central

In absence of their natural ligand 11-cis retinal, cone opsin GPCRs fail to traffic normally, a condition associated with photoreceptor degeneration and blindness. We created a mouse with a point mutation (F81Y) in cone S-opsin. As expected, cones with this knockin mutation respond to light with maximal sensitivity red-shifted from 360 nm to 420 nm, consistent with an altered interaction between the apoprotein and ligand, 11-cis retinal. However, cones expressing F81Y S-opsin showed an ~3-fold reduced absolute sensitivity that was associated with a corresponding reduction in S-opsin protein expression. The reduced S-opsin expression did not arise from decreased S-opsin mRNA or cone degeneration, but rather from enhanced ER-associated degradation (ERAD) of the nascent protein. Exogenously increased 11-cis retinal restored F81Y S-opsin protein expression to normal levels, suggesting that ligand binding in the ER facilitates proper folding. Immunohistochemistry and electron microscopy of normal retinas showed that Mueller cells, which synthesize a precursor of 11-cis retinal, are closely adjoined to the cone ER, so could deliver the ligand to the site of opsin synthesis. Together, these results suggest that the binding of 11-cis retinal in the ER is important for normal folding during cone opsin biosynthesis. PMID:22674284

Insinna, Christine; Daniele, Lauren L.; Davis, Jason A.; Larsen, DeLaine D.; Kuemmel, Colleen; Wang, Jinhua; Nikonov, Sergei S.; Knox, Barry E.; Pugh, Edward N.

2012-01-01

47

Expression Dynamics and Protein Localization of Rhabdomeric Opsins in Platynereis Larvae  

PubMed Central

The larval stages of polychaete annelids are often responsive to light and can possess one to six eyes. The early trochophore larvae of the errant annelid Platynereis dumerilii have a single pair of ventral eyespots, whereas older nectochaete larvae have an additional two pairs of dorsal eyes that will develop into the adult eyes. Early Platynereis trochophores show robust positive phototaxis starting on the first day of development. Even though the mechanism of phototaxis in Platynereis early trochophore larvae is well understood, no photopigment (opsin) expression has yet been described in this stage. In late trochophore larvae, a rhabdomeric-type opsin, r-opsin1, expressed in both the eyespots and the adult eyes has already been reported. Here, we identify another Platynereis rhabdomeric opsin, r-opsin3, that is expressed in a single photoreceptor in the eyespots in early trochophores, suggesting that it mediates early larval phototaxis. We also show that r-opsin1 and r-opsin3 are expressed in adjacent photoreceptor cells in the eyespots in later stages, indicating that a second eyespot-photoreceptor differentiates in late trochophore larvae. Using serial transmission electron microscopy (TEM), we identified and reconstructed both photoreceptors and a pigment cell in the late larval eyespot. We also characterized opsin expression in the adult eyes and found that the two opsins co-express there in several photoreceptor cells. Using antibodies recognizing r-opsin1 and r-opsin3 proteins, we demonstrate that both opsins localize to the rhabdomere in all six eyes. In addition, we found that r-opsin1 mRNA is localized to, and translated in, the projections of the adult eyes. The specific changes we describe in opsin transcription and translation and in the cellular complement suggest that the six larval eyes undergo spectral and functional maturation during the early planktonic phase of the Platynereis life cycle. PMID:23667045

Randel, Nadine; Bezares-Calderón, Luis A.; Gühmann, Martin; Shahidi, Réza; Jékely, Gáspár

2013-01-01

48

Evidence from opsin genes rejects nocturnality in ancestral primates  

E-print Network

Evidence from opsin genes rejects nocturnality in ancestral primates Ying Tan* , Anne D. Yoder, 2005 It is firmly believed that ancestral primates were nocturnal, with nocturnality having been among lineages. These observations suggest that the ancestral primates were diurnal or cathemeral

Yoder, Anne

49

Vertebrate ancient opsin photopigment spectra and the avian photoperiodic response  

PubMed Central

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 (?max = ?490 nm) for chicken VA photopigments. Furthermore, the spectral sensitivity of these photopigments match the peak absorbance of the avian photoperiodic response (?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. PMID:22031722

Davies, Wayne I. L.; Turton, Michael; Peirson, Stuart N.; Follett, Brian K.; Halford, Stephanie; Garcia-Fernandez, Jose M.; Sharp, Peter J.; Hankins, Mark W.; Foster, Russell G.

2012-01-01

50

Vertebrate ancient opsin photopigment spectra and the avian photoperiodic response.  

PubMed

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 (?(max) = ~490 nm) for chicken VA photopigments. Furthermore, the spectral sensitivity of these photopigments match the peak absorbance of the avian photoperiodic response (?(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. PMID:22031722

Davies, Wayne I L; Turton, Michael; Peirson, Stuart N; Follett, Brian K; Halford, Stephanie; Garcia-Fernandez, Jose M; Sharp, Peter J; Hankins, Mark W; Foster, Russell G

2012-04-23

51

The Origins of Novel Protein Interactions during Animal Opsin Evolution  

PubMed Central

Background Biologists are gaining an increased understanding of the genetic bases of phenotypic change during evolution. Nevertheless, the origins of phenotypes mediated by novel protein-protein interactions remain largely undocumented. Methodology/Principle Findings Here we analyze the evolution of opsin visual pigment proteins from the genomes of early branching animals, including a new class of opsins from Cnidaria. We combine these data with existing knowledge of the molecular basis of opsin function in a rigorous phylogenetic framework. We identify adaptive amino acid substitutions in duplicated opsin genes that correlate with a diversification of physiological pathways mediated by different protein-protein interactions. Conclusions/Significance This study documents how gene duplication events early in the history of animals followed by adaptive structural mutations increased organismal complexity by adding novel protein-protein interactions that underlie different physiological pathways. These pathways are central to vision and other photo-reactive phenotypes in most extant animals. Similar evolutionary processes may have been at work in generating other metazoan sensory systems and other physiological processes mediated by signal transduction. PMID:17940617

Plachetzki, David C.; Degnan, Bernard M.; Oakley, Todd H.

2007-01-01

52

Embryonic appearance of rod opsin in the urodele amphibian eye  

Microsoft Academic Search

Notophthalmus (Triturus) viridescens, a urodele amphibian (newt) common to the Eastern United States, is a promising subject for developmental and regeneration studies. We have available a monoclonal antibody shown to be specific in many vertebrates for rod opsin, the membrane apoprotein of the visual pigment rhodopsin. This antibody to an N-terminal epitope, by rigorous biochemical and immunological criteria, recognizes only

David Stephen McDevitt; Samir Kumar Brahma; Jean-Claude Jeanny

1993-01-01

53

True blue: S-opsin is widely expressed in different animal species.  

PubMed

Colour vision in animals is an interesting, fascinating subject. In this study, we examined a wide variety of species for expression of S-opsin (blue sensitive) and M-/L-opsin (green-red sensitive) in retinal cones using two novel monoclonal antibodies specific for peptides from human opsins. Mouse, rat and hare did not express one of the investigated epitopes, but we could clearly prove existence of cones through peanut agglutinin labelling. Retinas of guinea pig, dog, wolf, marten, cat, roe deer, pig and horse were positive for S-opsin, but not for M-/L-opsin. Nevertheless all these species are clearly at least dichromats, because we could detect further S-opsin negative cones by labelling with cone arrestin specific antibody. In contrast, pheasant and char had M-/L-opsin positive cones, but no S-opsin expressing cones. Sheep, cattle, monkey, men, pigeon, duck and chicken were positive for both opsins. Visual acuity analyzed through density of retinal ganglion cells revealed least visual discrimination by horses and highest resolution in pheasant and pigeon. Most mammals studied are dichromats with visual perception similar to red-green blind people. PMID:23173557

Amann, B; Hirmer, S; Hauck, S M; Kremmer, E; Ueffing, M; Deeg, C A

2014-02-01

54

Immunoreactive opsin in the pineal organ of reptiles and birds.  

PubMed

The presence of opsin was investigated with light microscopic immunocytochemistry in pinealocytes of reptiles and birds (Emys orbicularis, Pseudemys scripta elegans, Lacerta agilis et viridis, Gallus domesticus, Columba livia, Melopsittacus undulatus, Serinus canaria, Taeniopyga punctate). The outer segments of pinealocytes selectively bound antiopsin antibody as revealed by indirect immunocytochemical techniques, indicating the occurrence of a rhodopsin-like photopigment in these structures. The results were compared with those obtained in retinal photoreceptors of the same species as well as in the pineal organ of fishes and amphibians (Cyprinus carpio, Carassius auratus, Rana esculenta). Corresponding to immunoreactive structures seen in the light microscope, we found typical outer segments on a large number of pinealocytes in most of the reptiles and birds studied. The presence of opsin in the numerous well developed pineal outer segments of these reptilian and avian species contradicts the earlier hypothesis on the gradual regression of pineal sensitive structures in the avian line of evolution. PMID:6213109

Vigh, B; Vigh-Teichmann, I; Röhlich, P; Aros, B

1982-01-01

55

2006 LWS TR & T Solar Wind Focused Science Topic Team: The ... http://www.agu.org/cgi-bin/SFgate/SFgate?language=English&verb... 1 of 2 11/14/06 11:27 AM  

E-print Network

2006 LWS TR & T Solar Wind Focused Science Topic Team: The ... http://www=ng HR: 0800h AN: SH11A-0371 TI: 2006 LWS TR & T Solar Wind Focused Science Topic Team: The Beginnings AU;2006 LWS TR & T Solar Wind Focused Science Topic Team: The ... http://www

Ng, Chung-Sang

56

Visual sensitivities tuned by heterochronic shifts in opsin gene expression  

PubMed Central

Background Cichlid fishes have radiated into hundreds of species in the Great Lakes of Africa. Brightly colored males display on leks and vie to be chosen by females as mates. Strong discrimination by females causes differential male mating success, rapid evolution of male color patterns and, possibly, speciation. In addition to differences in color pattern, Lake Malawi cichlids also show some of the largest known shifts in visual sensitivity among closely related species. These shifts result from modulated expression of seven cone opsin genes. However, the mechanisms for this modulated expression are unknown. Results In this work, we ask whether these differences might result from changes in developmental patterning of cone opsin genes. To test this, we compared the developmental pattern of cone opsin gene expression of the Nile tilapia, Oreochromis niloticus, with that of several cichlid species from Lake Malawi. In tilapia, quantitative polymerase chain reaction showed that opsin gene expression changes dynamically from a larval gene set through a juvenile set to a final adult set. In contrast, Lake Malawi species showed one of two developmental patterns. In some species, the expressed gene set changes slowly, either retaining the larval pattern or progressing only from larval to juvenile gene sets (neoteny). In the other species, the same genes are expressed in both larvae and adults but correspond to the tilapia adult genes (direct development). Conclusion Differences in visual sensitivities among species of Lake Malawi cichlids arise through heterochronic shifts relative to the ontogenetic pattern of the tilapia outgroup. Heterochrony has previously been shown to be a powerful mechanism for change in morphological evolution. We found that altering developmental expression patterns is also an important mechanism for altering sensory systems. These resulting sensory shifts will have major impacts on visual communication and could help drive cichlid speciation. PMID:18500997

Carleton, Karen L; Spady, Tyrone C; Streelman, J Todd; Kidd, Michael R; McFarland, William N; Loew, Ellis R

2008-01-01

57

Beauty in the eye of the beholder: the two blue opsins of lycaenid butterflies and the opsin gene-driven evolution of sexually dimorphic eyes.  

PubMed

Although previous investigations have shown that wing coloration is an important component of social signaling in butterflies, the contribution of opsin evolution to sexual wing color dichromatism and interspecific divergence remains largely unexplored. Here we report that the butterfly Lycaena rubidus has evolved sexually dimorphic eyes due to changes in the regulation of opsin expression patterns to match the contrasting life histories of males and females. The L. rubidus eye contains four visual pigments with peak sensitivities in the ultraviolet (UV; lambdamax=360 nm), blue (B; lambdamax=437 nm and 500 nm, respectively) and long (LW; lambdamax=568 nm) wavelength range. By combining in situ hybridization of cloned opsin-encoding cDNAs with epi-microspectrophotometry, we found that all four opsin mRNAs and visual pigments are expressed in the eyes in a sex-specific manner. The male dorsal eye, which contains only UV and B (lambdamax=437 nm) visual pigments, indeed expresses two short wavelength opsin mRNAs, UVRh and BRh1. The female dorsal eye, which also has the UV and B (lambdamax=437 nm) visual pigments, also contains the LW visual pigment, and likewise expresses UVRh, BRh1 and LWRh mRNAs. Unexpectedly, in the female dorsal eye, we also found BRh1 co-expressed with LWRh in the R3-8 photoreceptor cells. The ventral eye of both sexes, on the other hand, contains all four visual pigments and expresses all four opsin mRNAs in a non-overlapping fashion. Surprisingly, we found that the 500 nm visual pigment is encoded by a duplicate blue opsin gene, BRh2. Further, using molecular phylogenetic methods we trace this novel blue opsin gene to a duplication event at the base of the Polyommatine+Thecline+Lycaenine radiation. The blue opsin gene duplication may help explain the blueness of blue lycaenid butterflies. PMID:16888057

Sison-Mangus, Marilou P; Bernard, Gary D; Lampel, Jochen; Briscoe, Adriana D

2006-08-01

58

Coexpression of three opsins in cone photoreceptors of the salamander Ambystoma tigrinum.  

PubMed

Although more than one type of visual opsin is present in the retina of most vertebrates, it was thought that each type of photoreceptor expresses only one opsin. However, evidence has accumulated that some photoreceptors contain more than one opsin, in many cases as a result of a developmental transition from the expression of one opsin to another. The salamander UV-sensitive (UV) cone is particularly notable because it contains three opsins (Makino and Dodd [1996] J Gen Physiol 108:27-34). Two opsin types are expressed at levels more than 100 times lower than the level of the primary opsin. Here, immunohistochemical experiments identified the primary component as a UV cone opsin and the two minor components as the short wavelength-sensitive (S) and long wavelength-sensitive (L) cone opsins. Based on single-cell recordings of 156 photoreceptors, the presence of three components in UV cones of hatchlings and terrestrial adults ruled out a developmental transition. There was no evidence for multiple opsin types within rods or S cones, but immunohistochemistry and partial bleaching in conjunction with single-cell recording revealed that both single and double L cones contained low levels of short wavelength-sensitive pigments in addition to the main L visual pigment. These results raise the possibility that coexpression of multiple opsins in other vertebrates was overlooked because a minor component absorbing at short wavelengths was masked by the main visual pigment or because the expression level of a component absorbing at long wavelengths was exceedingly low. PMID:24374736

Isayama, Tomoki; Chen, Ying; Kono, Masahiro; Fabre, Eduard; Slavsky, Michael; DeGrip, Willem J; Ma, Jian-Xing; Crouch, Rosalie K; Makino, Clint L

2014-07-01

59

Molecular characterization of visual pigments in Branchiopoda and the evolution of opsins in Arthropoda.  

PubMed

Studies on color vision in invertebrates have focused primarily on insect visual pigments, with little attention given to crustacean visual pigments. None of the blue-green-, blue-, or ultraviolet (UV)-sensitive-opsins have been identified in crustaceans. In addition, the discussion of visual pigments has been limited to long-wavelength-sensitive opsins in Pancrustacea. Here, we focused on Branchiopoda (Crustacea), which is a sister group of Hexapoda including insects. In the tadpole shrimp Triops granarius, the visual pigment chromophore was retinal. Multiple opsins were isolated from each of three branchiopod species, T. granarius, Triops longicaudatus, and the fairy shrimp Branchinella kugenumaensis (five, five, and four opsins from these species, respectively). Phylogenetic analyses and the presence of a lysine residue corresponding to position 90 in bovine rhodopsin suggested that three of the branchiopod opsins comprise UV-sensitive pigments. In addition, the phylogenetic relationships between insect and branchiopod UV-sensitive opsins revealed that the divergence of blue- and UV-sensitive pigments predates the Branchiopoda and Insecta divergence. The other branchiopod opsins show distant relationships to other known insect opsins and form novel clusters. The present results strongly suggest that the ancestral arthropod of the Chelicerata-Pancrustacea lineages possessed at least four types of opsins. The ancestors of Pancrustacea and the Insecta-Branchiopoda lineages possessed at least five and six types of opsins, respectively. Our results suggest that in the evolutionary process associated with each lineage, several opsins appeared and diversified with repeated gene duplication, of which some have been lost in some taxa. PMID:18984904

Kashiyama, Kazuyuki; Seki, Takaharu; Numata, Hideharu; Goto, Shin G

2009-02-01

60

Parallel Evolution of Opsin Gene Expression in African Cichlid Kelly E. O'Quin,*,1  

E-print Network

Parallel Evolution of Opsin Gene Expression in African Cichlid Fishes Kelly E. O'Quin,*,1 fishes is an excellent system with which to address this question. Cichlid fishes from Lakes Malawi (LM that gene regulation can make to rapid phenotypic evolution and adaptation. Key words: opsin, cichlids

Carleton, Karen L.

61

Divergent Selection on Opsins Drives Incipient Speciation in Lake Victoria Cichlids  

E-print Network

Divergent Selection on Opsins Drives Incipient Speciation in Lake Victoria Cichlids Yohey Terai1, et al. (2006) Divergent selection on opsins drives incipient speciation in Lake Victoria cichlids for the genetics of vertebrate speciation and adaptive radiation [8]. Lake Victoria, the largest of the African

62

Evolutionarily conserved and divergent regulatory sequences in the fish rod opsin promoter  

Microsoft Academic Search

Fish have multiple types and subtypes of opsin genes that are expressed in a highly regulated manner in retinal photoreceptor cells. In the rod opsin proximal promoter region (RPPR) of zebrafish (Danio rerio), the BAT 1 regulatory region contains highly conserved OTX (GATTA) and OTX-like (TATTA) sequences that can be recognized by the mammalian cone–rod homeobox (CRX) protein. However, binding

Shoji Kawamura; Kumiko Takeshita; Taro Tsujimura; Satoshi Kasagi; Yoshifumi Matsumoto

2005-01-01

63

Opsins from the lateral eyes and ocelli of the horseshoe crab, Limulus polyphemus.  

PubMed Central

cDNA clones encoding opsins from the lateral eyes and median ocelli of the horseshoe crab, Limulus polyphemus, were isolated from cDNA libraries. The opsin cDNAs obtained from the lateral eye and ocellar libraries code for deduced proteins with 376 amino acids. The two cDNAs are 96% identical at the nucleic acid level, differing primarily at the 3' untranslated region, and are apparently the products of two separate genes. The deduced opsin proteins are 99% identical to each other, differing at only 5 amino acids. The opsins encoded by these cDNAs are most likely the protein moiety of the visible-wavelength rhodopsins in this animal. In the lateral eye, expression of the opsin gene is restricted to the photoreceptor cells of the ommatidia. Comparisons with opsins of other species show that the Limulus opsin proteins are most similar (53% identity) to the opsin from the R1-6 photoreceptors of flies. Images Fig. 1 Fig. 2 Fig. 3 Fig. 4 PMID:8327495

Smith, W C; Price, D A; Greenberg, R M; Battelle, B A

1993-01-01

64

The lycaenid butterfly Polyommatus icarus uses a duplicated blue opsin to see green  

Microsoft Academic Search

SUMMARY The functional significance of gene duplication is rarely addressed at the level of animal behavior. Butterflies are excellent models in this regard because they can be trained and the use of their opsin-based visual pigments in color vision can be assessed. In the present study, we demonstrate that the lycaenid Polyommatus icarus uses its duplicate blue (B2) opsin, BRh2,

Marilou P. Sison-Mangus; Adriana D. Briscoe; Guillermo Zaccardi; H. Knuttel; Almut Kelber

2008-01-01

65

Opsin evolution and expression in Arthropod compound Eyes and Ocelli: Insights from the cricket Gryllus bimaculatus  

PubMed Central

Background Opsins are key proteins in animal photoreception. Together with a light-sensitive group, the chromophore, they form visual pigments which initiate the visual transduction cascade when photoactivated. The spectral absorption properties of visual pigments are mainly determined by their opsins, and thus opsins are crucial for understanding the adaptations of animal eyes. Studies on the phylogeny and expression pattern of opsins have received considerable attention, but our knowledge about insect visual opsins is still limited. Up to now, researchers have focused on holometabolous insects, while general conclusions require sampling from a broader range of taxa. We have therefore investigated visual opsins in the ocelli and compound eyes of the two-spotted cricket Gryllus bimaculatus, a hemimetabolous insect. Results Phylogenetic analyses place all identified cricket sequences within the three main visual opsin clades of insects. We assign three of these opsins to visual pigments found in the compound eyes with peak absorbances in the green (515 nm), blue (445 nm) and UV (332 nm) spectral range. Their expression pattern divides the retina into distinct regions: (1) the polarization-sensitive dorsal rim area with blue- and UV-opsin, (2) a newly-discovered ventral band of ommatidia with blue- and green-opsin and (3) the remainder of the compound eye with UV- and green-opsin. In addition, we provide evidence for two ocellar photopigments with peak absorbances in the green (511 nm) and UV (350 nm) spectral range, and with opsins that differ from those expressed in the compound eyes. Conclusions Our data show that cricket eyes are spectrally more specialized than has previously been assumed, suggesting that similar adaptations in other insect species might have been overlooked. The arrangement of spectral receptor types within some ommatidia of the cricket compound eyes differs from the generally accepted pattern found in holometabolous insect taxa and awaits a functional explanation. From the opsin phylogeny, we conclude that gene duplications, which permitted differential opsin expression in insect ocelli and compound eyes, occurred independently in several insect lineages and are recent compared to the origin of the eyes themselves. PMID:22935102

2012-01-01

66

Modeling Active Region Evolution - A New LWS TR and T Strategic Capability Model Suite  

NASA Technical Reports Server (NTRS)

In 2006 the LWS TR&T Program funded us to develop a strategic capability model of slowly evolving coronal active regions. In this poster we report on the overall design, and status of our new modeling suite. Our design features two coronal field models, a non-linear force free field model and a global 3D MHD code. The suite includes supporting tools and a user friendly GUI which will enable users to query the web for relevant magnetograms, download them, process them to synthesize a sequence of photospheric magnetograms and associated photospheric flow field which can then be applied to drive the coronal model innner boundary, run the coronal models and finally visualize the results.

MacNeice, Peter

2012-01-01

67

Structure and evolution of the teleost extraretinal rod-like opsin (errlo) and ocular rod opsin (rho) genes: is teleost rho a retrogene?  

PubMed

In Teleost fish examined to date the ocular rod opsin gene, rho, is intronless, unlike the rod opsin genes of other vertebrate classes which possess a five exon/four intron structure. We have examined in silico the structure of rho (which is expressed uniquely in the retina) and the closely related extraretinal rod-like opsin (exo-rhodopsin) gene, errlo (which is expressed uniquely in the pineal), in the puffer-fish, Fugu rubripes (Takifugu rubripes). Whilst the ocular rho is intronless in common with other Teleosts, the pineal errlo has the five exon/four intron structure common to the rod opsin gene of other vertebraes. A comparison of the sequence surrounding the errlo and rho loci indicates that the errlo locus is syntenic with RHO, the human rod opsin gene, rather than rho. We suggest that the intronless rho may have arisen through an ancient retrotransposition of a mature mRNA originating from errlo. This duplication event has occurred early in the evolution of the Actinopterygii (ray-finned fish) since the rho of the primitive Actinopterygians such as sturgeon, bowfin, and gar is also intronless. Since it appears that the intron containing errlo is the ancestral opsin gene that gave rise to the intronless rho in the Teleostei, errlo is therefore the true orthologue of the rod opsin gene in other vertebrate classes. We suggest that loss of expression of errlo in the retina could be related to the metabolic and physiological advantages, such as a reduction in splicing events during RNA processing, that may be conferred through possession of an additional, intronless rod opsin gene in the form of rho. PMID:13677319

Bellingham, James; Tarttelin, Emma E; Foster, Russell G; Wells, Dominic J

2003-06-15

68

Molecular expression of opsin gene in growing juvenile mackerel ( Scomber japonicus Houttuyn)  

NASA Astrophysics Data System (ADS)

Fish have developed color vision that is closely adapted to their photic environments, where both spectral sensitivity and the number of visual opsins are influenced. The mackerel used in this study is one of the most important fishery stocks in Korea. The opsin gene of the mackerel juveniles after 20 days in hatching was isolated and characterized based on the molecular study of visual photoreceptor. The full-length mackerel opsin gene was obtained by PCR amplification of genomic DNA, as well as cDNA synthesis. Sequence analysis of the opsin gene showed that it contained a 1,080 bp open reading frame encoding 360 amino acids. Based on Schiff’s base formation (S114, K119), glycosylation (E3, F37) and palmitoylation (S281, 282), the deduced amino acid sequence had a typical rod opsin. The mackerel and Gempylus serpens showed 73.7% DNA homology on opsin gene, which was higher than any other of investigated species. In the analysis of phylogenetic relationship, the genetic placement of the mackerel is closer to that of Scombroidei than Labroidei, with supporting somewhat strong bootstrap value. In the analysis of Northern and RT-PCR, the probed products were observed only in rapidly growing juveniles. These findings indicate that in mackerel opsin mRNA expression can be detected in day-20 hatching larvae. It may play an important role in stimulating growth hormone.

Kim, Eung-Oh; Yoon, Seong-Jong; Park, Kyoung-Hyun; Kim, Dae-Hyun; Do, Jeung-Wan; Cho, Eun-Seob

2009-12-01

69

Spectral tuning by opsin coexpression in retinal regions that view different parts of the visual field.  

PubMed

Vision frequently mediates critical behaviours, and photoreceptors must respond to the light available to accomplish these tasks. Most photoreceptors are thought to contain a single visual pigment, an opsin protein bound to a chromophore, which together determine spectral sensitivity. Mechanisms of spectral tuning include altering the opsin, changing the chromophore and incorporating pre-receptor filtering. A few exceptions to the use of a single visual pigment have been documented in which a single mature photoreceptor coexpresses opsins that form spectrally distinct visual pigments, and in these exceptions the functional significance of coexpression is unclear. Here we document for the first time photoreceptors coexpressing spectrally distinct opsin genes in a manner that tunes sensitivity to the light environment. Photoreceptors of the cichlid fish, Metriaclima zebra, mix different pairs of opsins in retinal regions that view distinct backgrounds. The mixing of visual pigments increases absorbance of the corresponding background, potentially aiding the detection of dark objects. Thus, opsin coexpression may be a novel mechanism of spectral tuning that could be useful for detecting prey, predators and mates. However, our calculations show that coexpression of some opsins can hinder colour discrimination, creating a trade-off between visual functions. PMID:25377457

Dalton, Brian E; Loew, Ellis R; Cronin, Thomas W; Carleton, Karen L

2014-12-22

70

Evolution and Expression Plasticity of Opsin Genes in a Fig Pollinator, Ceratosolen solmsi  

PubMed Central

Figs and fig pollinators have co-evolved species-specific systems of mutualism. So far, it was unknown how visual opsin genes of pollinators have evolved in the light conditions inside their host figs. We cloned intact full-length mRNA sequences of four opsin genes from a species of fig pollinator, Ceratosolen solmsi, and tested for selective pressure and expressional plasticity of these genes. Molecular evolutionary analysis indicated that the four opsin genes evolved under different selective constraints. Subsets of codons in the two long wavelength sensitive opsin (LW1, LW2) genes were positively selected in ancestral fig pollinators. The ultraviolet sensitive opsin (UV) gene was under strong purifying selection, whereas a relaxation of selective constrains occurred on several amino acids in the blue opsin. RT-qPCR analysis suggested that female and male fig pollinators had different expression patterns possibly due to their distinct lifestyles and different responses to light within the syconia. Co-evolutionary history with figs might have influenced the evolution and expression plasticity of opsin genes in fig pollinators. PMID:23342036

Bian, Sheng-Nan; Niu, Li-Ming; Murphy, Robert W.; Huang, Da-Wei

2013-01-01

71

Retinal Cone Photoreceptors of the Deer Mouse Peromyscus maniculatus: Development, Topography, Opsin Expression and Spectral Tuning  

PubMed Central

A quantitative analysis of photoreceptor properties was performed in the retina of the nocturnal deer mouse, Peromyscus maniculatus, using pigmented (wildtype) and albino animals. The aim was to establish whether the deer mouse is a more suitable model species than the house mouse for photoreceptor studies, and whether oculocutaneous albinism affects its photoreceptor properties. In retinal flatmounts, cone photoreceptors were identified by opsin immunostaining, and their numbers, spectral types, and distributions across the retina were determined. Rod photoreceptors were counted using differential interference contrast microscopy. Pigmented P. maniculatus have a rod-dominated retina with rod densities of about 450.000/mm2 and cone densities of 3000 - 6500/mm2. Two cone opsins, shortwave sensitive (S) and middle-to-longwave sensitive (M), are present and expressed in distinct cone types. Partial sequencing of the S opsin gene strongly supports UV sensitivity of the S cone visual pigment. The S cones constitute a 5-15% minority of the cones. Different from house mouse, S and M cone distributions do not have dorsoventral gradients, and coexpression of both opsins in single cones is exceptional (<2% of the cones). In albino P. maniculatus, rod densities are reduced by approximately 40% (270.000/mm2). Overall, cone density and the density of cones exclusively expressing S opsin are not significantly different from pigmented P. maniculatus. However, in albino retinas S opsin is coexpressed with M opsin in 60-90% of the cones and therefore the population of cones expressing only M opsin is significantly reduced to 5-25%. In conclusion, deer mouse cone properties largely conform to the general mammalian pattern, hence the deer mouse may be better suited than the house mouse for the study of certain basic cone properties, including the effects of albinism on cone opsin expression. PMID:24260509

Arbogast, Patrick; Glösmann, Martin; Peichl, Leo

2013-01-01

72

Retinal cone photoreceptors of the deer mouse Peromyscus maniculatus: development, topography, opsin expression and spectral tuning.  

PubMed

A quantitative analysis of photoreceptor properties was performed in the retina of the nocturnal deer mouse, Peromyscus maniculatus, using pigmented (wildtype) and albino animals. The aim was to establish whether the deer mouse is a more suitable model species than the house mouse for photoreceptor studies, and whether oculocutaneous albinism affects its photoreceptor properties. In retinal flatmounts, cone photoreceptors were identified by opsin immunostaining, and their numbers, spectral types, and distributions across the retina were determined. Rod photoreceptors were counted using differential interference contrast microscopy. Pigmented P. maniculatus have a rod-dominated retina with rod densities of about 450.000/mm(2) and cone densities of 3000-6500/mm(2). Two cone opsins, shortwave sensitive (S) and middle-to-longwave sensitive (M), are present and expressed in distinct cone types. Partial sequencing of the S opsin gene strongly supports UV sensitivity of the S cone visual pigment. The S cones constitute a 5-15% minority of the cones. Different from house mouse, S and M cone distributions do not have dorsoventral gradients, and coexpression of both opsins in single cones is exceptional (<2% of the cones). In albino P. maniculatus, rod densities are reduced by approximately 40% (270.000/mm(2)). Overall, cone density and the density of cones exclusively expressing S opsin are not significantly different from pigmented P. maniculatus. However, in albino retinas S opsin is coexpressed with M opsin in 60-90% of the cones and therefore the population of cones expressing only M opsin is significantly reduced to 5-25%. In conclusion, deer mouse cone properties largely conform to the general mammalian pattern, hence the deer mouse may be better suited than the house mouse for the study of certain basic cone properties, including the effects of albinism on cone opsin expression. PMID:24260509

Arbogast, Patrick; Glösmann, Martin; Peichl, Leo

2013-01-01

73

Three different cone opsin gene array mutational mechanisms with genotype-phenotype correlation and functional investigation of cone opsin variants.  

PubMed

Mutations in the OPN1LW (L-) and OPN1MW (M-)cone opsin genes underlie a spectrum of cone photoreceptor defects from stationary loss of color vision to progressive retinal degeneration. Genotypes of 22 families with a range of cone disorders were grouped into three classes: deletions of the locus control region (LCR); missense mutation (p.Cys203Arg) in an L-/M-hybrid gene; and exon 3 single-nucleotide polymorphism (SNP) interchange haplotypes in an otherwise normal gene array. Moderate-to-high myopia was observed in all mutation categories. Individuals with LCR deletions or p.Cys203Arg mutations were more likely to have nystagmus and poor vision, with disease progression in some p.Cys203Arg patients. Three disease-associated exon 3 SNP haplotypes encoding LIAVA, LVAVA, or MIAVA were identified in our cohort. These patients were less likely to have nystagmus but more likely to show progression, with all patients over the age of 40 years having marked macular abnormalities. Previously, the haplotype LIAVA has been shown to result in exon 3 skipping. Here, we show that haplotypes LVAVA and MIAVA also result in aberrant splicing, with a residual low level of correctly spliced cone opsin. The OPN1LW/OPN1MW:c.532A>G SNP, common to all three disease-associated haplotypes, appears to be principally responsible for this mutational mechanism. PMID:25168334

Gardner, Jessica C; Liew, Gerald; Quan, Ying-Hua; Ermetal, Burcu; Ueyama, Hisao; Davidson, Alice E; Schwarz, Nele; Kanuga, Naheed; Chana, Ravinder; Maher, Eamonn R; Webster, Andrew R; Holder, Graham E; Robson, Anthony G; Cheetham, Michael E; Liebelt, Jan; Ruddle, Jonathan B; Moore, Anthony T; Michaelides, Michel; Hardcastle, Alison J

2014-11-01

74

Three Different Cone Opsin Gene Array Mutational Mechanisms with Genotype–Phenotype Correlation and Functional Investigation of Cone Opsin Variants  

PubMed Central

Mutations in the OPN1LW (L-) and OPN1MW (M-)cone opsin genes underlie a spectrum of cone photoreceptor defects from stationary loss of color vision to progressive retinal degeneration. Genotypes of 22 families with a range of cone disorders were grouped into three classes: deletions of the locus control region (LCR); missense mutation (p.Cys203Arg) in an L-/M-hybrid gene; and exon 3 single-nucleotide polymorphism (SNP) interchange haplotypes in an otherwise normal gene array. Moderate-to-high myopia was observed in all mutation categories. Individuals with LCR deletions or p.Cys203Arg mutations were more likely to have nystagmus and poor vision, with disease progression in some p.Cys203Arg patients. Three disease-associated exon 3 SNP haplotypes encoding LIAVA, LVAVA, or MIAVA were identified in our cohort. These patients were less likely to have nystagmus but more likely to show progression, with all patients over the age of 40 years having marked macular abnormalities. Previously, the haplotype LIAVA has been shown to result in exon 3 skipping. Here, we show that haplotypes LVAVA and MIAVA also result in aberrant splicing, with a residual low level of correctly spliced cone opsin. The OPN1LW/OPN1MW:c.532A>G SNP, common to all three disease-associated haplotypes, appears to be principally responsible for this mutational mechanism. PMID:25168334

Gardner, Jessica C; Liew, Gerald; Quan, Ying-Hua; Ermetal, Burcu; Ueyama, Hisao; Davidson, Alice E; Schwarz, Nele; Kanuga, Naheed; Chana, Ravinder; Maher, Eamonn R; Webster, Andrew R; Holder, Graham E; Robson, Anthony G; Cheetham, Michael E; Liebelt, Jan; Ruddle, Jonathan B; Moore, Anthony T; Michaelides, Michel; Hardcastle, Alison J

2014-01-01

75

A ligand channel through the G protein coupled receptor opsin.  

PubMed

The G protein coupled receptor rhodopsin contains a pocket within its seven-transmembrane helix (TM) structure, which bears the inactivating 11-cis-retinal bound by a protonated Schiff-base to Lys296 in TM7. Light-induced 11-cis-/all-trans-isomerization leads to the Schiff-base deprotonated active Meta II intermediate. With Meta II decay, the Schiff-base bond is hydrolyzed, all-trans-retinal is released from the pocket, and the apoprotein opsin reloaded with new 11-cis-retinal. The crystal structure of opsin in its active Ops* conformation provides the basis for computational modeling of retinal release and uptake. The ligand-free 7TM bundle of opsin opens into the hydrophobic membrane layer through openings A (between TM1 and 7), and B (between TM5 and 6), respectively. Using skeleton search and molecular docking, we find a continuous channel through the protein that connects these two openings and comprises in its central part the retinal binding pocket. The channel traverses the receptor over a distance of ca. 70 A and is between 11.6 and 3.2 A wide. Both openings are lined with aromatic residues, while the central part is highly polar. Four constrictions within the channel are so narrow that they must stretch to allow passage of the retinal beta-ionone-ring. Constrictions are at openings A and B, respectively, and at Trp265 and Lys296 within the retinal pocket. The lysine enforces a 90 degrees elbow-like kink in the channel which limits retinal passage. With a favorable Lys side chain conformation, 11-cis-retinal can take the turn, whereas passage of the all-trans isomer would require more global conformational changes. We discuss possible scenarios for the uptake of 11-cis- and release of all-trans-retinal. If the uptake gate of 11-cis-retinal is assigned to opening B, all-trans is likely to leave through the same gate. The unidirectional passage proposed previously requires uptake of 11-cis-retinal through A and release of photolyzed all-trans-retinal through B. PMID:19194506

Hildebrand, Peter W; Scheerer, Patrick; Park, Jung Hee; Choe, Hui-Woog; Piechnick, Ronny; Ernst, Oliver P; Hofmann, Klaus Peter; Heck, Martin

2009-01-01

76

Imaging neural spiking in brain tissue using FRET-opsin protein voltage sensors  

E-print Network

Imaging neural spiking in brain tissue using FRET-opsin protein voltage sensors Yiyang Gong, Mark J of the MacQ-mCitrine sensor. We used this definition of SNR, because it takes into account the magnitude

Ferrari, Silvia

77

Molecular Characterization of Visual Pigments in Branchiopoda and the Evolution of Opsins in Arthropoda  

Microsoft Academic Search

Studies on color vision in invertebrates have focused primarily on insect visual pigments, with little attention given to crustacean visual pigments. None of the blue-green-, blue-, or ultraviolet (UV)-sensitive-opsins have been identified in crustaceans. In addition, the discussion of visual pigments has been limited to long-wavelength-sensitive opsins in Pancrustacea. Here, we focused on Branchiopoda (Crustacea), which is a sister group

Kazuyuki Kashiyama; Takaharu Seki; Hideharu Numata; Shin G. Goto

2009-01-01

78

Opsin expression in the rat retina is developmentally regulated by transcriptional activation.  

PubMed Central

The gene for rhodopsin, the primary light sensor of the visual system, is specifically expressed in the rod photoreceptor cells of the retina. We show here that in the rat, opsin RNA first accumulates to detectable levels at postnatal day 2 (PN2) and that nascent transcripts can be detected at PN1; this is the time when peak numbers of photoreceptor cells are generated by the final division of their neuroepithelial precursors. Accumulated opsin RNA then increases to reach the adult level, 0.06% of total retinal RNA, at about PN10. The transcription rate of the opsin gene increases to a similar extent over the same time course between PN3 and adulthood, suggesting that transcriptional activation is responsible for the increase in opsin expression. We used the antibody RET-P1 to show that rhodopsin protein is also detectable at PN2 and that the number of cells expressing the protein increases with time in a central-to-peripheral gradient in the retina. This increase in the number of differentiating photoreceptors in the tissue appears to account for much of the increase in opsin gene transcription and RNA accumulation. In situ hybridization to opsin RNA shows that it is restricted to the photoreceptor layer from the time it can first be detected, at PN7. Later in development, when RET-P1 staining shifts to the photoreceptor outer segments, opsin RNA becomes localized to the inner segments, suggesting that the distributions of opsin protein and RNA are related. Images PMID:2967911

Treisman, J E; Morabito, M A; Barnstable, C J

1988-01-01

79

RT-qPCR reveals opsin gene upregulation associated with age and sex in guppies ( Poecilia reticulata ) - a species with color-based sexual selection and 11 visual-opsin genes  

Microsoft Academic Search

Background  PCR-based surveys have shown that guppies (Poecilia reticulata) have an unusually large visual-opsin gene repertoire. This has led to speculation that opsin duplication and divergence\\u000a has enhanced the evolution of elaborate male coloration because it improves spectral sensitivity and\\/or discrimination in\\u000a females. However, this conjecture on evolutionary connections between opsin repertoire, vision, mate choice, and male coloration\\u000a was generated with

Christopher RJ Laver; John S Taylor

2011-01-01

80

Constitutive activation of phototransduction by K296E opsin is not a cause of photoreceptor degeneration.  

PubMed Central

The missense mutation Lys-296-->Glu (K296E) in the rhodopsin gene produces an opsin with no chromophore binding site and therefore is not activated by light. Nevertheless, the mutant opsin constitutively activates transducin in vitro and causes photoreceptor degeneration in vivo, possibly by continuously activating the phototransduction cascade, analogous to constant exposure to environmental light. We studied the K296E mutation in eight lines of transgenic mice. Each line developed photoreceptor degeneration with the rate of degeneration increasing monotonically as the ratio of mutant:wild-type opsin mRNA increased. At no time in the course of degeneration was there endogenous light adaptation in the retina as measured by the electroretinogram. The mutant opsin was found to be invariably phosphorylated and stably bound to arrestin. Light-independent activation of transducin was demonstrated only after the removal of arrestin and dephosphorylation of K296E opsin. Thus, K296E opsin in vivo does not activate the phototransduction cascade because it is shut off by photoreceptor inactivation mechanisms. Our data show that the K296E mutation does not cause photoreceptor degeneration by continuous activation of phototransduction. Images Fig. 1 Fig. 2 Fig. 3 Fig. 4 PMID:7724596

Li, T; Franson, W K; Gordon, J W; Berson, E L; Dryja, T P

1995-01-01

81

Correlative Sun-Earth-Connections Science Services in the Early Phase of LWS  

NASA Astrophysics Data System (ADS)

The Coordinated Data Analysis [Workshop] Web (CDAWeb) supports graphics and data retrieval from a unique database of current multi-mission Sun-Earth-Connections (SEC) data. The Satellite Situation Center Web (SSCWeb) serves satellite orbits and various multi-mission conjunctions queries. CDAWeb now acts as the US Cluster Science Data Center to serve Cluster Prime Parameters to authorized Cluster science investigators. These systems make current data quickly accessible to a wide research community and immediately available in the context of simultaneous data from almost all other current space physics missions. These systems are among the first working prototypes for delivering the class of integrated, multi-mission data view essential to the programs like Living with a Star (LWS). These systems' databases, capabilities, and usage continue to grow. CDAWeb served 160,000 plots and listings plus 206,000 file downloads in the year 2001, SSCWeb served 39,000 listings, query results and plots. CDAWeb now has 6 years where data from more 100 data sets is available for every day. Over the last year, CDAWeb has been extended to ~500 GBytes and added new datasets from Wind, Polar and other missions. CDAWeb remains hosted at three mirror sites (in Germany-MPE, England-RAL and Japan-ISAS) as well as by the primary site at Goddard. New higher-resolution data, new direct project data flows, new tools and our plans for evolution will be shown and demonstrated. Supported by the NASA Office of Space Science, CDAWeb and SSCWeb are joint efforts of the NASA GSFC Space Physics Data Facility (SPDF) and the National Space Science Data Center (NSSDC). These services are only possible in turn by data flows from various project data facilities and the work of the instrument science teams on the many missions now supported.

McGuire, R. E.; Burley, R. J.; Candey, R. M.; Chimiak, R. A.; Fung, S. F.; Harris, B. T.; Hills, H. K.; Johnson, R. C.; Kessel, R. L.; Kovalick, T. J.; Leckner, H. A.

2002-05-01

82

A spinal opsin controls early neural activity and drives a behavioral light response.  

PubMed

Nonvisual detection of light by the vertebrate hypothalamus, pineal, and retina is known to govern seasonal and circadian behaviors [1]. However, the expression of opsins in multiple other brain structures [2-4] suggests a more expansive repertoire for light regulation of physiology, behavior, and development. Translucent zebrafish embryos express extraretinal opsins early on [5, 6], at a time when spontaneous activity in the developing CNS plays a role in neuronal maturation and circuit formation [7]. Though the presence of extraretinal opsins is well documented, the function of direct photoreception by the CNS remains largely unknown. Here, we show that early activity in the zebrafish spinal central pattern generator (CPG) and the earliest locomotory behavior are dramatically inhibited by physiological levels of environmental light. We find that the photosensitivity of this circuit is conferred by vertebrate ancient long opsin A (VALopA), which we show to be a G?i-coupled receptor that is expressed in the neurons of the spinal network. Sustained photoactivation of VALopA not only suppresses spontaneous activity but also alters the maturation of time-locked correlated network patterns. These results uncover a novel role for nonvisual opsins and a mechanism for environmental regulation of spontaneous motor behavior and neural activity in a circuit previously thought to be governed only by intrinsic developmental programs. PMID:25484291

Friedmann, Drew; Hoagland, Adam; Berlin, Shai; Isacoff, Ehud Y

2015-01-01

83

Regeneration of bovine and octopus opsins in situ with natural and artificial retinals  

SciTech Connect

The authors consider the problem of color regulation in visual pigments for both bovine rhodopsin and octopus rhodopsin. Both pigments have 11-cis-retinal as their chromophore. These rhodopsins were bleached in their native membranes, and the opsins were regenerated with natural and artificial chromophores. Both bovine and octopus opsins were regenerated with the 9-cis- and 11-cis-retinal isomers, but the octopus opsin was additionally regenerated with the 13-cis and all-trans isomers. Titration of the octopus opsin with 11-cis-retinal gave an extinction coefficient for octopus rhodopsin of 27,000 {plus minus} 3,000 M{sup {minus}1} cm{sup {minus}1} at 475 nm. The absorption maxima of bovine artificial pigments formed by regenerating opsin with the 11-cis dihydro series of chromophores support a color regulation model for bovine rhodopsin in which the chromophore-binding site of the protein has two negative charges: one directly hydrogen bonded to the Schiff base nitrogen and another near carbon-13. Formation of octopus artificial pigments with both all-trans and 11-cis dihydro chromophores leads to a similar model for octopus rhodopsin and metarhodopsin: there are two negative charges in the chromophore-binding site, one directly hydrogen bonded to the Schiff base nitrogen and a second near carbon-13. The interaction of this second charge with the chromophore in octopus rhodopsin is weaker than in bovine, while in metarhodopsin it is as strong as in bovine.

Koutalos, Y.; Ebrey, T.G.; Tsuda, M.; Odashima, K.; Lien, T.; Park, M.H.; Shimizu, N.; Derguini, F.; Nakanishi, K.; Gilson, H.R.; Honig, B. (Univ. of Illinois, Urbana-Champaign (USA))

1989-03-21

84

Diurnal lighting patterns and habitat alter opsin expression and colour preferences in a killifish  

PubMed Central

Spatial variation in lighting environments frequently leads to population variation in colour patterns, colour preferences and visual systems. Yet lighting conditions also vary diurnally, and many aspects of visual systems and behaviour vary over this time scale. Here, we use the bluefin killifish (Lucania goodei) to compare how diurnal variation and habitat variation (clear versus tannin-stained water) affect opsin expression and the preference to peck at different-coloured objects. Opsin expression was generally lowest at midnight and dawn, and highest at midday and dusk, and this diurnal variation was many times greater than variation between habitats. Pecking preference was affected by both diurnal and habitat variation but did not correlate with opsin expression. Rather, pecking preference matched lighting conditions, with higher preferences for blue at noon and for red at dawn/dusk, when these wavelengths are comparatively scarce. Similarly, blue pecking preference was higher in tannin-stained water where blue wavelengths are reduced. In conclusion, L. goodei exhibits strong diurnal cycles of opsin expression, but these are not tightly correlated with light intensity or colour. Temporally variable pecking preferences probably result from lighting environment rather than from opsin production. These results may have implications for the colour pattern diversity observed in these fish. PMID:23698009

Johnson, Ashley M.; Stanis, Shannon; Fuller, Rebecca C.

2013-01-01

85

Reproducible and Sustained Regulation of G?s Signalling Using a Metazoan Opsin as an Optogenetic Tool  

Microsoft Academic Search

Originally developed to regulate neuronal excitability, optogenetics is increasingly also used to control other cellular processes with unprecedented spatiotemporal resolution. Optogenetic modulation of all major G-protein signalling pathways (Gq, Gi and Gs) has been achieved using variants of mammalian rod opsin. We show here that the light response driven by such rod opsin-based tools dissipates under repeated exposure, consistent with

Helena J. Bailes; Ling-Yu Zhuang; Robert J. Lucas

2012-01-01

86

ISO-LWS detection of the 112 micron HD J=1-0 line toward the Orion Bar  

E-print Network

We report the first detection outside of the solar system of the lowest pure rotational J=1-0 transition of the HD molecule at 112 microns. The detection was made toward the Orion Bar using the Fabry-Perot of the Long Wavelength Spectrometer (LWS) on board the Infrared Space Observatory (ISO). The line appears in emission with an integrated flux of (0.93+/-0.17)e-19 Watts per cm squared in the LWS beam, implying a beam-averaged column density in the v=0, J=1 state of (1.2+/-0.2)e17 molecules per cm squared. Assuming LTE excitation, the total HD column density is (2.9+/-0.8)e17 molecules per cm squared for temperatures between 85 and 300 K. Combined with the total warm molecular hydrogen (H2) column density of about (1.5-3.0)e22 molecules per cm squared derived from either the H2 pure rotational lines, C18O observations or dust continuum emission, the implied HD abundance, HD/H2, ranges from 0.7e-5 to 2.6e-5, with a preferred value of (2.0+/-0.6)e-5. The corresponding deuterium abundance of [D]/[H]=(1.0+/-0.3)e-5 is compared with recent values derived from ultraviolet absorption line observations of atomic HI and DI in interstellar clouds in the solar neighborhood and in Orion.

Christopher M. Wright; Ewine F. van Dishoeck; Pierre Cox; Sunil D. Sidher; Martin F. Kessler

1999-01-28

87

Adenosine A(2a) receptor-mediated inhibition of rod opsin mRNA expression in tiger salamander.  

PubMed

The neuromodulator adenosine mediates dark-adaptive changes in retinal photoreceptors through A(2a) receptors. In cold-blooded vertebrates, opsin mRNA expression is lower at night than during the day. In the present study, we tested whether adenosine could inhibit opsin mRNA expression in cultured rod cells and if endogenous adenosine acts to suppress opsin mRNA in the intact retina at night. Semi-quantitative in situ hybridization showed that treatment with 100 nm of the A(2a)/A(2b) agonist N(6)-[2-(3,5-dimethoxyphenyl)-2-(2-methylphenyl)-ethyl]adenosine (DPMA) reduced opsin mRNA 41% in cultured rod cells. The effect of DPMA was blocked by 10 microm of the A(2a) antagonist 8-(3-chlorostyryl)caffeine (CSC) but not by 10 microm of the A(2b) antagonist alloxazine. One micromolar adenosine alone had no effect on opsin mRNA. However, in the presence of the adenosine deaminase inhibitor erythro-9-(2-hydroxy-3-nonyl)adenine hydrochloride (EHNA), 1 microm adenosine reduced opsin mRNA 61%. EHNA alone reduced opsin mRNA by 26%. Consistent with an A(2a) receptor mechanism, 100 nm forskolin (adenylate cyclase agonist) decreased opsin mRNA 34%. Finally, northern blots showed that intravitreal injection of 10 microm CSC at night increased opsin I mRNA 38%. Thus, endogenous adenosine suppresses rod opsin I mRNA expression at night; in vitro results indicate this reduction occurs through A(2a)-like receptor binding and stimulation of adenylate cyclase activity. PMID:12390528

Alfinito, Peter D; Alli, Roshni; Townes-Anderson, Ellen

2002-11-01

88

Molecular Evidence that Only Two Opsin Subfamilies, the Blue Light- (SWS2) and Green Light-Sensitive (RH2), Drive Color Vision in Atlantic Cod (Gadus morhua)  

PubMed Central

Teleosts show a great variety in visual opsin complement, due to both gene duplication and gene loss. The repertoire ranges from one subfamily of visual opsins (scotopic vision) including rod opsin only retinas seen in many deep-sea species to multiple subfamilies of visual opsins in some pelagic species. We have investigated the opsin repertoire of Atlantic cod (Gadus morhua) using information in the recently sequenced cod genome and found that despite cod not being a deep sea species it lacks visual subfamilies sensitive towards the most extreme parts of the light spectra representing UV and red light. Furthermore, we find that Atlantic cod has duplicated paralogs of both blue-sensitive SWS2 and green-sensitive RH2 subfamilies, with members belonging to each subfamily linked in tandem within the genome (two SWS2-, and three RH2A genes, respectively). The presence of multiple cone opsin genes indicates that there have been duplication events in the cod ancestor SWS2 and RH2 opsins producing paralogs that have been retained in Atlantic. Our results are supported by expressional analysis of cone opsins, which further revealed an ontogenetic change in the array of cone opsins expressed. These findings suggest life stage specific programs for opsin regulation which could be linked to habitat changes and available light as the larvae is transformed into an early juvenile. Altogether we provide the first molecular evidence for color vision driven by only two families of cone opsins due to gene loss in a teleost. PMID:25551396

Søviknes, Anne Mette; Drivenes, Øyvind; Helvik, Jon Vidar

2014-01-01

89

Live-cell imaging evidence for the ciliary transport of rod photoreceptor opsin by heterotrimeric kinesin-2.  

PubMed

Primary cilia detect extracellular signals through membrane receptors and channels. The outer segment of a vertebrate photoreceptor cell represents the most elaborate of all primary cilia, containing extraordinarily large amounts of the visual receptor protein, opsin. Because of its high abundance, opsin represents a potential model system for the study of ciliary membrane receptors, including their transport. Here, we have analyzed the movement of ciliary opsin to test whether the highly conserved intraflagellar transport (IFT), as driven by heterotrimeric kinesin-2, is required. Results show that opsin can enter and move along the primary cilium of a nonphotoreceptor cell (an hTERT-RPE1 epithelial cell), suggesting that it can co-opt the basic anterograde motor system of cilia. Fluorescence recovery after photobleaching analysis of cilia of hTERT-RPE1 cells showed that the movement of ciliary opsin was comparable to that of the IFT protein, IFT88. Moreover, the movement of opsin in these cilia, as well as in cilia of mouse rod photoreceptor cells, was reduced significantly when KIF3A, the obligate motor subunit of heterotrimeric kinesin-2, was deficient. These studies therefore provide evidence from live-cell analysis that the conserved heterotrimeric kinesin-2 is required for the normal transport of opsin along the ciliary plasma membrane. PMID:22855808

Trivedi, Deepti; Colin, Emilie; Louie, Carrie M; Williams, David S

2012-08-01

90

Dysfunction of heterotrimeric kinesin-2 in rod photoreceptor cells and the role of opsin mislocalization in rapid cell death.  

PubMed

Due to extensive elaboration of the photoreceptor cilium to form the outer segment, axonemal transport (IFT) in photoreceptors is extraordinarily busy, and retinal degeneration is a component of many ciliopathies. Functional loss of heterotrimeric kinesin-2, a major anterograde IFT motor, causes mislocalized opsin, followed by rapid cell death. Here, we have analyzed the nature of protein mislocalization and the requirements for the death of kinesin-2-mutant rod photoreceptors. Quantitative immuno EM showed that opsin accumulates initially within the inner segment, and then in the plasma membrane. The light-activated movement of arrestin to the outer segment is also impaired, but this defect likely results secondarily from binding to mislocalized opsin. Unlike some other retinal degenerations, neither opsin-arrestin complexes nor photoactivation were necessary for cell loss. In contrast, reduced rod opsin expression provided enhanced rod and cone photoreceptor survival and function, as measured by photoreceptor cell counts, apoptosis assays, and ERG analysis. The cell death incurred by loss of kinesin-2 function was almost completely negated by Rho?/?. Our results indicate that mislocalization of opsin is a major cause of photoreceptor cell death from kinesin-2 dysfunction and demonstrate the importance of accumulating mislocalized protein per se, rather than specific signaling properties of opsin, stemming from photoactivation or arrestin binding. PMID:20926680

Lopes, Vanda S; Jimeno, David; Khanobdee, Kornnika; Song, Xiaodan; Chen, Bryan; Nusinowitz, Steven; Williams, David S

2010-12-01

91

Expression and Evolution of Short Wavelength Sensitive Opsins in Colugos: A Nocturnal Lineage That Informs Debate on Primate Origins.  

PubMed

A nocturnal activity pattern is central to almost all hypotheses on the adaptive origins of primates. This enduring view has been challenged in recent years on the basis of variation in the opsin genes of nocturnal primates. A correspondence between the opsin genes and activity patterns of species in Euarchonta-the superordinal group that includes the orders Primates, Dermoptera (colugos), and Scandentia (treeshrews)-could prove instructive, yet the basic biology of the dermopteran visual system is practically unknown. Here we show that the eye of the Sunda colugo (Galeopterus variegatus) lacks a tapetum lucidum and has an avascular retina, and we report on the expression and spectral sensitivity of cone photopigments. We found that Sunda colugos have intact short wavelength sensitive (S-) and long wavelength sensitive (L-) opsin genes, and that both opsins are expressed in cone photoreceptors of the retina. The inferred peak spectral sensitivities are 451 and 562 nm, respectively. In line with adaptation to nocturnal vision, cone densities are low. Surprisingly, a majority of S-cones coexpress some L-opsin. We also show that the ratio of rates of nonsynonymous to synonymous substitutions of exon 1 of the S-opsin gene is indicative of purifying selection. Taken together, our results suggest that natural selection has favored a functional S-opsin in a nocturnal lineage for at least 45 million years. Accordingly, a nocturnal activity pattern remains the most likely ancestral character state of euprimates. PMID:24293738

Moritz, Gillian L; Lim, Norman T-L; Neitz, Maureen; Peichl, Leo; Dominy, Nathaniel J

2013-01-01

92

Intraspecific cone opsin expression variation in the cichlids of Lake Malawi  

E-print Network

Intraspecific cone opsin expression variation in the cichlids of Lake Malawi ADAM R. SMITH. The Fisherian model suggests that Correspondence: Adam R. Smith, Fax: (301) 314 6262; E-mail: adasmi@umd.edu �,* LINDSAY D'ANNUNZIO,* ABBI E. SMITH,* ANIT SHARMA,* CHRISTOPHER M. HOFMANN,* N. J. MARSHALL§ and KAREN L

Carleton, Karen L.

93

Opsin Evolution in Damselfish: Convergence, Reversal, and Parallel Evolution Across Tuning Sites  

E-print Network

and opsin genotypes. In previous studies of African cichlid fishes, we found evidence for positive selection family (Pomacentridae), a group of reef fishes that are distributed widely and have a documented fossil et al. 2001), and the visual system has become a model for understanding functional adaptation

Carleton, Karen L.

94

Evolution of the Cichlid Visual Palette through Ontogenetic Subfunctionalization of the Opsin Gene Arrays  

E-print Network

, the forces governing the retention and death of opsin genes are poorly understood. African cichlid fishes, Oreochromis niloticus, which is an ancestral outgroup to the cichlid adaptive radiations in the Great African among the cichlid species of the lacustrine adaptive radiations. Introduction Gene duplication has been

Carleton, Karen L.

95

The relationship between lens transmission and opsin gene expression in cichlids from Lake Malawi  

E-print Network

trans- mission and SWS1 (UV) opsin gene expression, suggesting that UV transmitting lenses are adaptive considerable variation in lens transmission among fishes (Thorpe, Douglas, & Truscott, 1993). For example, coral reef fish have lens cutoff wavelengths ranging from 320 to 440 nm (Losey et al., 2003; Siebeck

Carleton, Karen L.

96

Phenotypic plasticity in opsin expression in a butterfly compound eye complements sex role  

E-print Network

Phenotypic plasticity in opsin expression in a butterfly compound eye complements sex role reversal complements sex role reversal Andrew Everett1* , Xiaoling Tong1 , Adriana D Briscoe2 and Antónia Monteiro1 forms, wet and dry, that vary in wing ornament brightness and in the identity of the sex that performs

Monteiro, Antónia

97

Reproducible and Sustained Regulation of Gas Signalling Using a Metazoan Opsin as an Optogenetic Tool  

E-print Network

Originally developed to regulate neuronal excitability, optogenetics is increasingly also used to control other cellular processes with unprecedented spatiotemporal resolution. Optogenetic modulation of all major G-protein signalling pathways (Gq, Gi and Gs) has been achieved using variants of mammalian rod opsin. We show here that the light response driven by such rod opsin-based tools dissipates under repeated exposure, consistent with the known bleaching characteristics of this photopigment. We continue to show that replacing rod opsin with a bleach resistant opsin from Carybdea rastonii, the box jellyfish, (JellyOp) overcomes this limitation. Visible light induced high amplitude, reversible, and reproducible increases in cAMP in mammalian cells expressing JellyOp. While single flashes produced a brief cAMP spike, repeated stimulation could sustain elevated levels for 10s of minutes. JellyOp was more photosensitive than currently available optogenetic tools, responding to white light at irradiances $1 mW/cm 2. We conclude that JellyOp is a promising new tool for mimicking the activity of Gs-coupled G protein coupled receptors with fine spatiotemporal resolution.

Helena J. Bailes; Ling-yu Zhuang; Robert J. Lucas

2011-01-01

98

Electrostatic Compensation Restores Trafficking of the Autosomal Recessive Retinitis Pigmentosa E150K Opsin  

E-print Network

Electrostatic Compensation Restores Trafficking of the Autosomal Recessive Retinitis Pigmentosa E investigated the molecu- lar mechanisms underlying opsin retention in the Golgi appara- tus. Electrostatic, partial restoration of the surface electrostatic charge in the com- pensatory R69E/E150K double mutant

Palczewski, Krzysztof

99

New evidence for the role of heterochrony in the repeated evolution of cichlid opsin expression.  

PubMed

SUMMARY Lake Malawi (LM) cichlids have undergone heterochronic shifts in the expression of their cone opsin genes, the genes responsible for color vision. These shifts have generated species with short-, middle-, and long-wavelength-sensitive cone photoreceptors and visual systems. However, it is unclear when during the evolution of African cichlids these shifts occurred, or whether they could account for similar short- and middle-wavelength-sensitive profiles among unrelated cichlids in Lake Tanganyika (LT). To address these questions, we surveyed opsin expression in developing fry of two African cichlids, Astatotilapia burtoni from LT and Melanochromis auratus from LM. We found that A. burtoni expresses a series of three different single-cone opsins over the course of development, while M. auratus exhibits variation in the expression of only two. Neither A. burtoni nor M. auratus exhibits much variation in the expression of its double-cone opsins. These patterns reveal that A. burtoni exhibits progressive development in the sensitivity of its single-cone photoreceptors, but direct development in the sensitivity of its double-cone photoreceptors. M. auratus exhibits neotenic development in the sensitivity of both photoreceptor sets. Given the intermediate phylogenetic placement of A. burtoni between cichlids from LT and LM, our results suggest that the ancestor of LM's cichlids exhibited a progressive developmental pattern of opsin expression. These results indicate that the heterochronic shifts which produced the short- and middle-wavelength-sensitive profiles of LM's cichlids occurred recently, and suggest that the presence of similar profiles among LT's cichlids are due to parallel heterochronic shifts. PMID:21410875

O'Quin, Kelly E; Smith, Adam R; Sharma, Anit; Carleton, Karen L

2011-01-01

100

Opsins in Limulus eyes: characterization of three visible light-sensitive opsins unique to and co-expressed in median eye photoreceptors and a peropsin/RGR that is expressed in all eyes.  

PubMed

The eyes of the horseshoe crab Limulus polyphemus have long been used for studies of basic mechanisms of vision, and the structure and physiology of Limulus photoreceptors have been examined in detail. Less is known about the opsins Limulus photoreceptors express. We previously characterized a UV opsin (LpUVOps1) that is expressed in all three types of Limulus eyes (lateral compound eyes, median ocelli and larval eyes) and three visible light-sensitive rhabdomeric opsins (LpOps1, -2 and -5) that are expressed in Limulus lateral compound and larval eyes. Physiological studies showed that visible light-sensitive photoreceptors are also present in median ocelli, but the visible light-sensitive opsins they express were unknown. In the current study we characterize three newly identified, visible light-sensitive rhabdomeric opsins (LpOps6, -7 and -8) that are expressed in median ocelli. We show that they are ocellar specific and that all three are co-expressed in photoreceptors distinct from those expressing LpUVOps1. Our current findings show that the pattern of opsin expression in Limulus eyes is much more complex than previously thought and extend our previous observations of opsin co-expression in visible light-sensitive Limulus photoreceptors. We also characterize a Limulus peropsin/RGR (LpPerOps1). We examine the phylogenetic relationship of LpPerOps1 with other peropsins and RGRs, demonstrate that LpPerOps1 transcripts are expressed in each of the three types of Limulus eyes and show that the encoded protein is expressed in membranes of cells closely associated with photoreceptors in each eye type. These finding suggest that peropsin was in the opsin repertoire of euchelicerates. PMID:25524988

Battelle, Barbara-Anne; Kempler, Karen E; Saraf, Spencer R; Marten, Catherine E; Dugger, Donald R; Speiser, Daniel I; Oakley, Todd H

2015-02-01

101

Supplementary Figure S1. IHC of TG worms expressing (b)opsin in neurons and in muscles. a-g, Representative IHC images of live day 1 TG worms expressing (b)opsin in neurons Alexa-488-  

E-print Network

Supplementary Figure S1. IHC of TG worms expressing (b)opsin in neurons and in muscles. a-g, Representative IHC images of live day 1 TG worms expressing (b)opsin in neurons Alexa-488- conjugated 1D4 mAb was injected into pseudocoelom of a worm head (a-d) or middle body section (e-g) together with Triton X-100

Palczewski, Krzysztof

102

Signatures of functional constraint at aye-aye opsin genes: the potential of adaptive color vision in a nocturnal primate.  

PubMed

While color vision perception is thought to be adaptively correlated with foraging efficiency for diurnal mammals, those that forage exclusively at night may not need color vision nor have the capacity for it. Indeed, although the basic condition for mammals is dichromacy, diverse nocturnal mammals have only monochromatic vision, resulting from functional loss of the short-wavelength sensitive opsin gene. However, many nocturnal primates maintain intact two opsin genes and thus have dichromatic capacity. The evolutionary significance of this surprising observation has not yet been elucidated. We used a molecular population genetics approach to test evolutionary hypotheses for the two intact opsin genes of the fully nocturnal aye-aye (Daubentonia madagascariensis), a highly unusual and endangered Madagascar primate. No evidence of gene degradation in either opsin gene was observed for any of 8 aye-aye individuals examined. Furthermore, levels of nucleotide diversity for opsin gene functional sites were lower than those for 15 neutrally evolving intergenic regions (>25 kb in total), which is consistent with a history of purifying selection on aye-aye opsin genes. The most likely explanation for these findings is that dichromacy is advantageous for aye-ayes despite their nocturnal activity pattern. We speculate that dichromatic nocturnal primates may be able to perceive color while foraging under moonlight conditions, and suggest that behavioral and ecological comparisons among dichromatic and monochromatic nocturnal primates will help to elucidate the specific activities for which color vision perception is advantageous. PMID:17575304

Perry, George H; Martin, Robert D; Verrelli, Brian C

2007-09-01

103

Enhancer/Promoter Activities of the Long/Middle Wavelength-Sensitive Opsins of Vertebrates Mediated by Thyroid Hormone Receptor ?2 and COUP-TFII  

PubMed Central

Cone photopigments (opsins) are crucial elements of, and the first detection module in, color vision. Individual opsins have different wavelength sensitivity patterns, and the temporal and spatial expression patterns of opsins are unique and stringently regulated. Long and middle wavelength-sensitive (L/M) opsins are of the same phylogenetic type. Although the roles of thyroid hormone/TRß2 and COUP-TFs in the transcriptional regulation of L/M opsins have been explored, the detailed mechanisms, including the target sequence in the enhancer of L/M opsins, have not been revealed. We aimed to reveal molecular mechanisms of L/M opsins in vertebrates. Using several human red opsin enhancer/promoter-luciferase reporter constructs, we found that TRß2 increased luciferase activities through the 5?-UTR and intron 3–4 region, whereas the presence of T3 affected only the intron 3–4 region-dependent luciferase activity. Furthermore, COUP-TFII suppressed intron 3–4 region-dependent luciferase activities. However, luciferase expression driven by the mouse M opsin intron 3–4 region was only slightly increased by TRß2, and rather enhanced by COUP-TFII. To determine whether these differential responses reflect differences between primates and rodents, we examined the enhancer/promoter region of the red opsin of the common marmoset. Interestingly, while TRß2 increased 5?-UTR- or intron 3–4 region-driven luciferase expression, as observed for the human red opsin, expression of the latter luciferase was not suppressed by COUP-TFII. In fact, immunostaining of common marmoset retinal sections revealed expression of COUP-TFII and red opsin in the cone cells. PMID:24058409

Iida, Atsumi; Itoh, Toshio; Watanabe, Sumiko

2013-01-01

104

Light-controlled inhibition of malignant glioma by opsin gene transfer  

PubMed Central

Glioblastomas are aggressive cancers with low survival rates and poor prognosis because of their highly proliferative and invasive capacity. In the current study, we describe a new optogenetic strategy that selectively inhibits glioma cells through light-controlled membrane depolarization and cell death. Transfer of the engineered opsin ChETA (engineered Channelrhodopsin-2 variant) gene into primary human glioma cells or cell lines, but not normal astrocytes, unexpectedly decreased cell proliferation and increased mitochondria-dependent apoptosis, upon light stimulation. These optogenetic effects were mediated by membrane depolarization-induced reductions in cyclin expression and mitochondrial transmembrane potential. Importantly, the ChETA gene transfer and light illumination in mice significantly inhibited subcutaneous and intracranial glioma growth and increased the survival of the animals bearing the glioma. These results uncover an unexpected effect of opsin ion channels on glioma cells and offer the opportunity for the first time to treat glioma using a light-controllable optogenetic approach. PMID:24176851

Yang, F; Tu, J; Pan, J-Q; Luo, H-L; Liu, Y-H; Wan, J; Zhang, J; Wei, P-F; Jiang, T; Chen, Y-H; Wang, L-P

2013-01-01

105

Honeybee Blue and Ultraviolet-Sensitive Opsins: Cloning, Heterologous Expression in Drosophila, and Physiological Characterization  

Microsoft Academic Search

The honeybee (Apis mellifera) visual system contains three classes of retinal photoreceptor cells that are maximally sensi- tive to light at 440 nm (blue), 350 nm (ultraviolet), and 540 nm (green). We performed a PCR-based screen to identify the genes encoding the Apis blue- and ultraviolet (UV)-sensitive opsins. We obtained cDNAs that encode proteins having a high degree of sequence

Steven M. Townson; Belinda S. W. Chang; Ernesto Salcedo; Linda V. Chadwell; Naomi E. Pierce; Steven G. Britt

1998-01-01

106

Opsin localization and rhodopsin photochemistry in a transgenic mouse model of retinitis pigmentosa  

Microsoft Academic Search

The VPP mouse is a transgenic strain carrying three mutations (P23H, V20G, P27L) near the N-terminus of opsin, the apoprotein of rhodopsin, the rod photopigment. These animals exhibit a slowly progressive degeneration of the rod photoreceptors, and concomitant changes in retinal function that mimic those seen in humans with autosomal dominant retinitis pigmentosa resulting from a point mutation (P23H) in

T.-H Wu; T. D Ting; T.-I. L Okajima; D. R Pepperberg; Y.-K Ho; H Ripps; M. I Naash

1998-01-01

107

Light- and electron-microscopic demonstration of immunoreactive opsin in the pinealocytes of various vertebrates.  

PubMed

An antibody to opsin isolated from rod outer segments of the frog retina was applied in light- and electron-microscopic immunocytochemical studies to the pineal organ of various vertebrates (Cyprinus carpio, Carassius auratus, Rana esculenta, Emys orbicularis, Pseudemys scripta elegans, Lacerta agilis and viridis. Gallus domesticus, Columba livia, Melopsittacus undulatus, Serinus canaria, Taeniopyga punctata, Didelphis virginiana, Erinaceus roumanicus, Myotis myotis, rabbit, rat, cat). PMID:6458362

Vigh, B; Vigh-Teichmann, I

1981-01-01

108

Ancestral duplications and highly dynamic opsin gene evolution in percomorph fishes  

PubMed Central

Single-gene and whole-genome duplications are important evolutionary mechanisms that contribute to biological diversification by launching new genetic raw material. For example, the evolution of animal vision is tightly linked to the expansion of the opsin gene family encoding light-absorbing visual pigments. In teleost fishes, the most species-rich vertebrate group, opsins are particularly diverse and key to the successful colonization of habitats ranging from the bioluminescence-biased but basically dark deep sea to clear mountain streams. In this study, we report a previously unnoticed duplication of the violet-blue short wavelength-sensitive 2 (SWS2) opsin, which coincides with the radiation of highly diverse percomorph fishes, permitting us to reinterpret the evolution of this gene family. The inspection of close to 100 fish genomes revealed that, triggered by frequent gene conversion between duplicates, the evolutionary history of SWS2 is rather complex and difficult to predict. Coincidentally, we also report potential cases of gene resurrection in vertebrate opsins, whereby pseudogenized genes were found to convert with their functional paralogs. We then identify multiple novel amino acid substitutions that are likely to have contributed to the adaptive differentiation between SWS2 copies. Finally, using the dusky dottyback Pseudochromis fuscus, we show that the newly discovered SWS2A duplicates can contribute to visual adaptation in two ways: by gaining sensitivities to different wavelengths of light and by being differentially expressed between ontogenetic stages. Thus, our study highlights the importance of comparative approaches in gaining a comprehensive view of the dynamics underlying gene family evolution and ultimately, animal diversification. PMID:25548152

Cortesi, Fabio; Musilová, Zuzana; Stieb, Sara M.; Hart, Nathan S.; Siebeck, Ulrike E.; Malmstrøm, Martin; Tørresen, Ole K.; Jentoft, Sissel; Cheney, Karen L.; Marshall, N. Justin; Carleton, Karen L.; Salzburger, Walter

2015-01-01

109

Evolutionary renovation of L/M opsin polymorphism confers a fruit discrimination advantage to ateline New World monkeys.  

PubMed

New World monkeys exhibit prominent colour vision variation due to allelic polymorphism of the long-to-middle wavelength (L/M) opsin gene. The known spectral variation of L/M opsins in primates is broadly determined by amino acid composition at three sites: 180, 277 and 285 (the 'three-sites' rule). However, two L/M opsin alleles found in the black-handed spider monkeys (Ateles geoffroyi) are known exceptions, presumably due to novel mutations. The spectral separation of the two L/M photopigments is 1.5 times greater than expected based on the 'three-sites' rule. Yet the consequence of this for the visual ecology of the species is unknown, as is the evolutionary mechanism by which spectral shift was achieved. In this study, we first examine L/M opsins of two other Atelinae species, the long-haired spider monkeys (A. belzebuth) and the common woolly monkeys (Lagothrix lagotricha). By a series of site-directed mutagenesis, we show that a mutation Y213D (tyrosine to aspartic acid at site 213) in the ancestral opsin of the two alleles enabled N294K, which occurred in one allele of the ateline ancestor and increased the spectral separation between the two alleles. Second, by modelling the chromaticity of dietary fruits and background leaves in a natural habitat of spider monkeys, we demonstrate that chromatic discrimination of fruit from leaves is significantly enhanced by these mutations. This evolutionary renovation of L/M opsin polymorphism in atelines illustrates a previously unappreciated dynamism of opsin genes in shaping primate colour vision. PMID:24612406

Matsumoto, Yoshifumi; Hiramatsu, Chihiro; Matsushita, Yuka; Ozawa, Norihiro; Ashino, Ryuichi; Nakata, Makiko; Kasagi, Satoshi; Di Fiore, Anthony; Schaffner, Colleen M; Aureli, Filippo; Melin, Amanda D; Kawamura, Shoji

2014-04-01

110

Evolutionary renovation of L/M opsin polymorphism confers a fruit discrimination advantage to ateline New World monkeys  

PubMed Central

New World monkeys exhibit prominent colour vision variation due to allelic polymorphism of the long-to-middle wavelength (L/M) opsin gene. The known spectral variation of L/M opsins in primates is broadly determined by amino acid composition at three sites: 180, 277 and 285 (the ‘three-sites’ rule). However, two L/M opsin alleles found in the black-handed spider monkeys (Ateles geoffroyi) are known exceptions, presumably due to novel mutations. The spectral separation of the two L/M photopigments is 1.5 times greater than expected based on the ‘three-sites’ rule. Yet the consequence of this for the visual ecology of the species is unknown, as is the evolutionary mechanism by which spectral shift was achieved. In this study, we first examine L/M opsins of two other Atelinae species, the long-haired spider monkeys (A. belzebuth) and the common woolly monkeys (Lagothrix lagotricha). By a series of site-directed mutagenesis, we show that a mutation Y213D (tyrosine to aspartic acid at site 213) in the ancestral opsin of the two alleles enabled N294K, which occurred in one allele of the ateline ancestor and increased the spectral separation between the two alleles. Second, by modelling the chromaticity of dietary fruits and background leaves in a natural habitat of spider monkeys, we demonstrate that chromatic discrimination of fruit from leaves is significantly enhanced by these mutations. This evolutionary renovation of L/M opsin polymorphism in atelines illustrates a previously unappreciated dynamism of opsin genes in shaping primate colour vision. PMID:24612406

Matsumoto, Yoshifumi; Hiramatsu, Chihiro; Matsushita, Yuka; Ozawa, Norihiro; Ashino, Ryuichi; Nakata, Makiko; Kasagi, Satoshi; Di Fiore, Anthony; Schaffner, Colleen M; Aureli, Filippo; Melin, Amanda D; Kawamura, Shoji

2014-01-01

111

Point mutations in bovine opsin can be classified in four groups with respect to their effect on the biosynthetic pathway of opsin.  

PubMed Central

Expression in vitro with the recombinant baculovirus expression system showed correct biosynthesis and post-translational processing of "wild-type' bovine opsin with regard to translocation, glycosylation, palmitoylation and targeting. However, several of these processes were severely affected by point mutations. From the overall results of 16 mutants reported here, four groups were distinguished. One group significantly affected neither biosynthesis nor folding of opsin (D83N, P291A, A299C-V300A-P303G). A second group produced a truncated protein (R69H, Y301F), suggesting that these positions are essential for a correct translational process. A third group affected membrane translocation as well as glycosylation, which can be interpreted as interference with the function of a transfer signal. Substitutions at positions Glu-113, Glu-122, Glu-134, Arg-135 and Lys-248 belong to this category. A fourth group induced structural changes in the protein that led to heterogeneous distribution in the plasma membrane (E113Q/D, W265F, Y268S). Taking any functional consequences of these mutations into consideration, it seems that point mutations can have mosaic effects and therefore should be examined at several levels (folding, targeting, functional parameters). PMID:9003366

DeCaluwé, G L; DeGrip, W J

1996-01-01

112

Point mutations in bovine opsin can be classified in four groups with respect to their effect on the biosynthetic pathway of opsin.  

PubMed

Expression in vitro with the recombinant baculovirus expression system showed correct biosynthesis and post-translational processing of "wild-type' bovine opsin with regard to translocation, glycosylation, palmitoylation and targeting. However, several of these processes were severely affected by point mutations. From the overall results of 16 mutants reported here, four groups were distinguished. One group significantly affected neither biosynthesis nor folding of opsin (D83N, P291A, A299C-V300A-P303G). A second group produced a truncated protein (R69H, Y301F), suggesting that these positions are essential for a correct translational process. A third group affected membrane translocation as well as glycosylation, which can be interpreted as interference with the function of a transfer signal. Substitutions at positions Glu-113, Glu-122, Glu-134, Arg-135 and Lys-248 belong to this category. A fourth group induced structural changes in the protein that led to heterogeneous distribution in the plasma membrane (E113Q/D, W265F, Y268S). Taking any functional consequences of these mutations into consideration, it seems that point mutations can have mosaic effects and therefore should be examined at several levels (folding, targeting, functional parameters). PMID:9003366

DeCaluwé, G L; DeGrip, W J

1996-12-15

113

Chemical and radiative transfer modelling of the ISO-LWS Fabry-Perot spectra of Orion-KL water lines  

NASA Astrophysics Data System (ADS)

We present chemical and radiative transfer models for the many far-infrared ortho- and para-H2O lines that were observed from the Orion-KL region in high resolution Fabry-Pérot (FP) mode by the Long Wavelength Spectrometer (LWS) on board the Infrared Space Observatory (ISO). The chemistry of the region was first studied by simulating the conditions in the different known components of Orion-KL: chemical models for a hot core, a plateau and a ridge were coupled with an accelerated ?-iteration radiative transfer model to predict H2O line fluxes and profiles. Our models include the first 45 energy levels of ortho- and para-H2O. We find that lines arising from energy levels below 560 K were best reproduced by a gas of density 3 × 105cm-3 at a temperature of 70-90 K, expanding at a velocity of 30kms-1 and with a H2O/H2 abundance ratio of the order of 2-3 × 10-5, similar to the abundance derived by Cernicharo et al. However, the model that best reproduces the fluxes and profiles of H2O lines arising from energy levels above 560 K has a significantly higher H2O/H2 abundance, 1-5 × 10-4, originating from gas of similar density, in the Plateau region, that has been heated to 300 K, relaxing to 90-100 K. We conclude that the observed water lines do not originate from high-temperature shocks.

Lerate, M. R.; Yates, J. A.; Barlow, M. J.; Viti, S.; Swinyard, B. M.

2010-08-01

114

Nucleotide Polymorphisms Upstream of the X-chromosome Opsin Gene Array Tune L:M Cone Ratio  

PubMed Central

In support of the long-held idea that cone ratio is genetically determined by variation linked to the X-chromosome opsin gene locus, the present study identified nucleotide differences in DNA segments containing regulatory regions of the L and M opsin genes that are associated with significant differences in the relative number of L versus M cones. Specific haplotypes (combinations of genetic differences) were identified that correlated with high versus low L:M cone ratio. These findings are consistent with the biological principle that DNA sequence variations affect binding affinities for protein components of complexes that influence the relative probability that an L versus M opsin gene will be silenced during development, and in turn, produce variation in the proportion of L to M cones. PMID:18598397

Gunther, Karen L.; Neitz, Jay

2008-01-01

115

Inferred L/M cone opsin polymorphism of ancestral tarsiers sheds dim light on the origin of anthropoid primates  

PubMed Central

Tarsiers are small nocturnal primates with a long history of fuelling debate on the origin and evolution of anthropoid primates. Recently, the discovery of M and L opsin genes in two sister species, Tarsius bancanus (Bornean tarsier) and Tarsius syrichta (Philippine tarsier), respectively, was interpreted as evidence of an ancestral long-to-middle (L/M) opsin polymorphism, which, in turn, suggested a diurnal or cathemeral (arrhythmic) activity pattern. This view is compatible with the hypothesis that stem tarsiers were diurnal; however, a reversion to nocturnality during the Middle Eocene, as evidenced by hyper-enlarged orbits, predates the divergence of T. bancanus and T. syrichta in the Late Miocene. Taken together, these findings suggest that some nocturnal tarsiers possessed high-acuity trichromatic vision, a concept that challenges prevailing views on the adaptive origins of the anthropoid visual system. It is, therefore, important to explore the plausibility and antiquity of trichromatic vision in the genus Tarsius. Here, we show that Sulawesi tarsiers (Tarsius tarsier), a phylogenetic out-group of Philippine and Bornean tarsiers, have an L opsin gene that is more similar to the L opsin gene of T. syrichta than to the M opsin gene of T. bancanus in non-synonymous nucleotide sequence. This result suggests that an L/M opsin polymorphism is the ancestral character state of crown tarsiers and raises the possibility that many hallmarks of the anthropoid visual system evolved under dim (mesopic) light conditions. This interpretation challenges the persistent nocturnal–diurnal dichotomy that has long informed debate on the origin of anthropoid primates. PMID:23536597

Melin, Amanda D.; Matsushita, Yuka; Moritz, Gillian L.; Dominy, Nathaniel J.; Kawamura, Shoji

2013-01-01

116

A Naturally Occurring Mutation of the Opsin Gene (T4R) in Dogs Affects Glycosylation and Stability of the G Protein-coupled Receptor*  

PubMed Central

Rho (rhodopsin; opsin plus 11-cis-retinal) is a prototypical G protein-coupled receptor responsible for the capture of a photon in retinal photoreceptor cells. A large number of mutations in the opsin gene associated with autosomal dominant retinitis pigmentosa have been identified. The naturally occurring T4R opsin mutation in the English mastiff dog leads to a progressive retinal degeneration that closely resembles human retinitis pigmentosa caused by the T4K mutation in the opsin gene. Using genetic approaches and biochemical assays, we explored the properties of the T4R mutant protein. Employing immunoaffinity-purified Rho from affected RHOT4R/T4R dog retina, we found that the mutation abolished glycosylation at Asn2, whereas glycosylation at Asn15 was unaffected, and the mutant opsin localized normally to the rod outer segments. Moreover, we found that T4R Rho* lost its chromophore faster as measured by the decay of meta-rhodopsin II and that it was less resistant to heat denaturation. Detergent-solubilized T4R opsin regenerated poorly and interacted abnormally with the G protein transducin (Gt). Structurally, the mutation affected mainly the “plug” at the intradiscal (extracellular) side of Rho, which is possibly responsible for protecting the chromophore from the access of bulk water. The T4R mutation may represent a novel molecular mechanism of degeneration where the unliganded form of the mutant opsin exerts a detrimental effect by losing its structural integrity. PMID:15459196

Zhu, Li; Jang, Geeng-Fu; Jastrzebska, Beata; Filipek, S?awomir; Pearce-Kelling, Susan E.; Aguirre, Gustavo D.; Stenkamp, Ronald E.; Acland, Gregory M.; Palczewski, Krzysztof

2005-01-01

117

Parallel reduction in expression, but no loss of functional constraint, in two opsin paralogs within cave populations of Gammarus minus (Crustacea: Amphipoda)  

PubMed Central

Background Gammarus minus, a freshwater amphipod living in the cave and surface streams in the eastern USA, is a premier candidate for studying the evolution of troglomorphic traits such as pigmentation loss, elongated appendages, and reduced eyes. In G. minus, multiple pairs of genetically related, physically proximate cave and surface populations exist which exhibit a high degree of intraspecific morphological divergence. The morphology, ecology, and genetic structure of these sister populations are well characterized, yet the genetic basis of their morphological divergence remains unknown. Results We used degenerate PCR primers designed to amplify opsin genes within the subphylum Crustacea and discovered two distinct opsin paralogs (average inter-paralog protein divergence???20%) in the genome of three independently derived pairs of G. minus cave and surface populations. Both opsin paralogs were found to be related to other crustacean middle wavelength sensitive opsins. Low levels of nucleotide sequence variation (< 1% within populations) were detected in both opsin genes, regardless of habitat, and dN/dS ratios did not indicate a relaxation of functional constraint in the cave populations with reduced or absent eyes. Maximum likelihood analyses using codon-based models also did not detect a relaxation of functional constraint in the cave lineages. We quantified expression level of both opsin genes and found that the expression of both paralogs was significantly reduced in all three cave populations relative to their sister surface populations. Conclusions The concordantly lowered expression level of both opsin genes in cave populations of G. minus compared to sister surface populations, combined with evidence for persistent purifying selection in the cave populations, is consistent with an unspecified pleiotropic function of opsin proteins. Our results indicate that phototransduction proteins such as opsins may have retained their function in cave-adapted organisms because they may play a pleiotropic role in other important processes that are unrelated to vision. PMID:23617561

2013-01-01

118

Metal Mesh Fabrication and Testing for Infrared Astronomy and ISO Science Programs; ISO GO Data Analysis and LWS Instrument Team Activities  

NASA Technical Reports Server (NTRS)

This research program addresses astrophysics research with the Infrared Space Observatory's Long Wavelength Spectrometer (ISO-LWS), including efforts to supply ISO-LWS with superior metal mesh filters. This grant has, over the years, enabled Dr. Smith in his role as a Co-Investigator on the satellite, the PI (Principal Investigator) on the Extragalactic Science Team, and a member of the Calibration and performance working groups. The emphasis of the budget in this proposal is in support of Dr. Smith's Infrared Space Observatory research. This program began (under a different grant number) while Dr. Smith was at the Smithsonian's National Air and Space Museum, and was transferred to SAO with a change in number. While Dr. Smith was a visiting Discipline Scientist at NASA HQ the program was in abeyance, but it has resumed in full since his return to SAO. The Infrared Space Observatory mission was launched in November, 1996, and since then has successfully completed its planned lifetime mission. Data are currently being calibrated to the 2% level.

Smith, Howard A.; Oliversen, Ronald J. (Technical Monitor)

2001-01-01

119

Autosomal recessive retinitis pigmentosa E150K opsin mice exhibit photoreceptor disorganization  

PubMed Central

The pathophysiology of the E150K mutation in the rod opsin gene associated with autosomal recessive retinitis pigmentosa (arRP) has yet to be determined. We generated knock-in mice carrying a single nucleotide change in exon 2 of the rod opsin gene resulting in the E150K mutation. This novel mouse model displayed severe retinal degeneration affecting rhodopsin’s stabilization of rod outer segments (ROS). Homozygous E150K (KK) mice exhibited early-onset retinal degeneration, with disorganized ROS structures, autofluorescent deposits in the subretinal space, and aberrant photoreceptor phagocytosis. Heterozygous (EK) mice displayed a delayed-onset milder retinal degeneration. Further, mutant receptors were mislocalized to the inner segments and perinuclear region. Though KK mouse rods displayed markedly decreased phototransduction, biochemical studies of the mutant rhodopsin revealed only minimally affected chromophore binding and G protein activation. Ablation of the chromophore by crossing KK mice with mice lacking the critical visual cycle protein LRAT slowed retinal degeneration, whereas blocking phototransduction by crossing KK mice with GNAT1-deficient mice slightly accelerated this process. This study highlights the importance of proper higher-order organization of rhodopsin in the native tissue and provides information about the signaling properties of this mutant rhodopsin. Additionally, these results suggest that patients heterozygous for the E150K mutation should be periodically reevaluated for delayed-onset retinal degeneration. PMID:23221340

Zhang, Ning; Kolesnikov, Alexander V.; Jastrzebska, Beata; Mustafi, Debarshi; Sawada, Osamu; Maeda, Tadao; Genoud, Christel; Engel, Andreas; Kefalov, Vladimir J.; Palczewski, Krzysztof

2012-01-01

120

Blue-light-receptive cryptochrome is expressed in a sponge eye lacking neurons and opsin.  

PubMed

Many larval sponges possess pigment ring eyes that apparently mediate phototactic swimming. Yet sponges are not known to possess nervous systems or opsin genes, so the unknown molecular components of sponge phototaxis must differ fundamentally from those in other animals, inspiring questions about how this sensory system functions. Here we present molecular and biochemical data on cryptochrome, a candidate gene for functional involvement in sponge pigment ring eyes. We report that Amphimedon queenslandica, a demosponge, possesses two cryptochrome/photolyase genes, Aq-Cry1 and Aq-Cry2. The mRNA of one gene (Aq-Cry2) is expressed in situ at the pigment ring eye. Additionally, we report that Aq-Cry2 lacks photolyase activity and contains a flavin-based co-factor that is responsive to wavelengths of light that also mediate larval photic behavior. These results suggest that Aq-Cry2 may act in the aneural, opsin-less phototaxic behavior of a sponge. PMID:22442365

Rivera, Ajna S; Ozturk, Nuri; Fahey, Bryony; Plachetzki, David C; Degnan, Bernard M; Sancar, Aziz; Oakley, Todd H

2012-04-15

121

The evolution of irradiance detection: melanopsin and the non-visual opsins  

PubMed Central

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. PMID:19720649

Peirson, Stuart N.; Halford, Stephanie; Foster, Russell G.

2009-01-01

122

Allelic Variation in Malawi Cichlid Opsins: A Tale of Two Genera Adam R. Smith Karen L. Carleton  

E-print Network

Allelic Variation in Malawi Cichlid Opsins: A Tale of Two Genera Adam R. Smith · Karen L. Carleton speciation (Kornfield and Smith 2000; Danley and Kocher 2001; Gen- ner and Turner 2005). Lakes Malawi00239-010-9355-x) contains supplementary material, which is available to authorized users. A. R. Smith

Carleton, Karen L.

123

Complex patterns of divergence among green-sensitive (RH2a) African cichlid opsins revealed by Clade model analyses  

PubMed Central

Background Gene duplications play an important role in the evolution of functional protein diversity. Some models of duplicate gene evolution predict complex forms of paralog divergence; orthologous proteins may diverge as well, further complicating patterns of divergence among and within gene families. Consequently, studying the link between protein sequence evolution and duplication requires the use of flexible substitution models that can accommodate multiple shifts in selection across a phylogeny. Here, we employed a variety of codon substitution models, primarily Clade models, to explore how selective constraint evolved following the duplication of a green-sensitive (RH2a) visual pigment protein (opsin) in African cichlids. Past studies have linked opsin divergence to ecological and sexual divergence within the African cichlid adaptive radiation. Furthermore, biochemical and regulatory differences between the RH2a? and RH2a? paralogs have been documented. It thus seems likely that selection varies in complex ways throughout this gene family. Results Clade model analysis of African cichlid RH2a opsins revealed a large increase in the nonsynonymous-to-synonymous substitution rate ratio (?) following the duplication, as well as an even larger increase, one consistent with positive selection, for Lake Tanganyikan cichlid RH2a? opsins. Analysis using the popular Branch-site models, by contrast, revealed no such alteration of constraint. Several amino acid sites known to influence spectral and non-spectral aspects of opsin biochemistry were found to be evolving divergently, suggesting that orthologous RH2a opsins may vary in terms of spectral sensitivity and response kinetics. Divergence appears to be occurring despite intronic gene conversion among the tandemly-arranged duplicates. Conclusions Our findings indicate that variation in selective constraint is associated with both gene duplication and divergence among orthologs in African cichlid RH2a opsins. At least some of this variation may reflect an adaptive response to differences in light environment. Interestingly, these patterns only became apparent through the use of Clade models, not through the use of the more widely employed Branch-site models; we suggest that this difference stems from the increased flexibility associated with Clade models. Our results thus bear both on studies of cichlid visual system evolution and on studies of gene family evolution in general. PMID:23078361

2012-01-01

124

Opsins with mutations at the site of chromophore attachment constitutively activate transducin but are not phosphorylated by rhodopsin kinase.  

PubMed Central

More than 70 mutations in the gene encoding the visual pigment rhodopsin have been identified in patients with autosomal dominant retinitis pigmentosa. Most of these mutations are thought to interfere with proper folding of the membrane protein. However, families with a severe phenotype of retinitis pigmentosa have been identified and shown to carry a mutation at the site of chromophore attachment, Lys-296. This mutation disrupts the inactive conformation of opsin and results in a constitutively active protein that can activate the rod-specific GTP-binding protein, transducin, in the absence of light and in the absence of the chromophore 11-cis-retinal. It has been suggested that this mutant opsin molecule may cause rod degeneration by depletion of the components used to inactivate rhodopsin, such as rhodopsin kinase. In this work we test this idea by determining whether two constitutively active opsin mutants are phosphorylated by rhodopsin kinase. We found that opsin mutants where Lys-296 is replaced either by Glu (K296E) or by Gly (K296G) are not substrates of rhodopsin kinase in the absence of chromophore. However, when K296G is regenerated with a Schiff base complex of 11-cis-retinal and n-propylamine and exposed to illumination, phosphorylation of opsin occurs. These experiments suggest that in the rod photoreceptors of patients with retinitis pigmentosa carrying a mutation at Lys-296, there is persistent activation of the GTP-binding protein-mediated cascade. This may result in a situation that mimics long-term exposure to continuous illumination and results in the degeneration of photoreceptors. Images PMID:8202499

Robinson, P R; Buczy?ko, J; Ohguro, H; Palczewski, K

1994-01-01

125

Site-directed mutagenesis of highly conserved amino acids in the first cytoplasmic loop of Drosophila Rh1 opsin blocks rhodopsin synthesis in the nascent state.  

PubMed Central

The cytoplasmic surface of Drosophila melanogaster Rh1 rhodopsin (ninaE) harbours amino acids which are highly conserved among G-protein-coupled receptors. Site-directed mutations which cause Leu81Gln or Asn86Ile amino acid substitutions in the first cytoplasmic loop of the Rh1 opsin protein, are shown to block rhodopsin synthesis in the nascent, glycosylated state from which the mutant opsin is degraded rapidly. In mutants Leu81Gln and Asn86Ile, only 20-30% and <2% respectively, of functional rhodopsins are synthesized and transported to the photoreceptive membrane. Thus, conserved amino acids in opsin's cytoplasmic surface are a critical factor in the interaction of opsin with proteins of the rhodopsin processing machinery. Photoreceptor cells expressing mutant rhodopsins undergo age-dependent degeneration in a recessive manner. PMID:9130705

Bentrop, J; Schwab, K; Pak, W L; Paulsen, R

1997-01-01

126

Principles for applying optogenetic tools derived from direct comparative analysis of microbial opsins  

PubMed Central

Diverse optogenetic tools have allowed versatile control over neural activity. Many depolarizing and hyperpolarizing tools have now been developed in multiple laboratories and tested across different preparations, presenting opportunities but also making it difficult to draw direct comparisons. This challenge has been compounded by the dependence of performance on parameters such as vector, promoter, expression time, illumination, cell type and many other variables. As a result, it has become increasingly complicated for end users to select the optimal reagents for their experimental needs. For a rapidly growing field, critical figures of merit should be formalized both to establish a framework for further development and so that end users can readily understand how these standardized parameters translate into performance. Here we systematically compared microbial opsins under matched experimental conditions to extract essential principles and identify key parameters for the conduct, design and interpretation of experiments involving optogenetic techniques. PMID:22179551

Mattis, Joanna; Tye, Kay M; Ferenczi, Emily A; Ramakrishnan, Charu; O’Shea, Daniel J; Prakash, Rohit; Gunaydin, Lisa A; Hyun, Minsuk; Fenno, Lief E; Gradinaru, Viviana; Yizhar, Ofer; Deisseroth, Karl

2014-01-01

127

Optical control of neuronal excitation and inhibition using a single opsin protein, ChR2  

PubMed Central

The effect of electrical stimulation on neuronal membrane potential is frequency dependent. Low frequency electrical stimulation can evoke action potentials, whereas high frequency stimulation can inhibit action potential transmission. Optical stimulation of channelrhodopsin-2 (ChR2) expressed in neuronal membranes can also excite action potentials. However, it is unknown whether optical stimulation of ChR2-expressing neurons produces a transition from excitation to inhibition with increasing light pulse frequencies. Here we report optical inhibition of motor neuron and muscle activity in vivo in the cooled sciatic nerves of Thy1-ChR2-EYFP mice. We also demonstrate all-optical single-wavelength control of neuronal excitation and inhibition without co-expression of inhibitory and excitatory opsins. This all-optical system is free from stimulation-induced electrical artifacts and thus provides a new approach to investigate mechanisms of high frequency inhibition in neuronal circuits in vivo and in vitro. PMID:24173561

Liske, Holly; Qian, Xiang; Anikeeva, Polina; Deisseroth, Karl; Delp, Scott

2013-01-01

128

Optical control of neuronal excitation and inhibition using a single opsin protein, ChR2  

NASA Astrophysics Data System (ADS)

The effect of electrical stimulation on neuronal membrane potential is frequency dependent. Low frequency electrical stimulation can evoke action potentials, whereas high frequency stimulation can inhibit action potential transmission. Optical stimulation of channelrhodopsin-2 (ChR2) expressed in neuronal membranes can also excite action potentials. However, it is unknown whether optical stimulation of ChR2-expressing neurons produces a transition from excitation to inhibition with increasing light pulse frequencies. Here we report optical inhibition of motor neuron and muscle activity in vivo in the cooled sciatic nerves of Thy1-ChR2-EYFP mice. We also demonstrate all-optical single-wavelength control of neuronal excitation and inhibition without co-expression of inhibitory and excitatory opsins. This all-optical system is free from stimulation-induced electrical artifacts and thus provides a new approach to investigate mechanisms of high frequency inhibition in neuronal circuits in vivo and in vitro.

Liske, Holly; Qian, Xiang; Anikeeva, Polina; Deisseroth, Karl; Delp, Scott

2013-10-01

129

Identification of the sites in opsin modified by photoactivated azido[125I]iodobenzene.  

PubMed Central

Opsin labelled with photoactivated 1-azido-4-[125I]iodobenzene was proteolysed in situ with Staphylococcus aureus V8 proteinase to yield two radioactive membrane-bound fragments. These were separated, cleaved with CNBr and the resultant peptides sequenced in order to locate the radiolabelled residues. In the whole molecule, there was clear evidence for modification of at least 20 sites, identified as derivatives of cysteine, tryptophan, tyrosine, histidine and lysine residues. The probe primary reacted, therefore, with nucleophilic substituents. The positions of the modified sites relative to the confines of the phospholipid bilayer were consistent with all other studies on the disposition of the polypeptide chain. The location of these sites substantiated an earlier suggestion that not all the transmembrane segments should be regarded as continuous regular alpha-helices. PMID:2944512

Davison, M D; Findlay, J B

1986-01-01

130

Coexpression of opsin- and VIP-like-immunoreactivity in CSF-contacting neurons of the avian brain  

Microsoft Academic Search

Cerebrospinal fluid-contacting (CSF) cells in both the septal and the tuberal areas in the brain of the ring dove are labeled by RET-P1, a monoclonal antibody to opsin that reacts with inner and outer segment membranes of rod photoreceptors in a variety of vertebrates. Immunoblot analysis of proteins from diverse brain regions, however, revealed bands of anti-RET-P1 immunoreactivity that did

Rae Silver; P. Witkovsky; P. Horvath; V. Alones; C. J. Barnstable; M. N. Lehman

1988-01-01

131

Characterization and regulation of the protein binding to a cis-acting element, RET 1, in the rat opsin promoter  

Microsoft Academic Search

RET 1 is a binding site for retinal nuclear proteins located at ?136 to ?110 bp in the rat opsin promoter, as defined by DNase\\u000a protection assays. A similar sequence is found in the upstream flanking regions of many other photoreceptor genes in mammals\\u000a and other species, includingDrosophila. A 7-base consensus sequence, CAATTAG, is found in these genes and has

Xiu Yu; Colin J. Barnstable

1994-01-01

132

Characterization of Opsin Gene Alleles Affecting Color Vision in a Wild Population of Titi Monkeys (Callicebus brunneus)  

PubMed Central

The color vision of most platyrrhine primates is determined by alleles at the polymorphic X-linked locus coding for the opsin responsible for the middle- to long-wavelength (M/L) cone photopigment. Females who are heterozygous at the locus have trichromatic vision while homozygous females and all males are dichromatic. This study characterized the opsin alleles in a wild population of the socially monogamous platyrrhine monkey Callicebus brunneus (the brown titi monkey), a primate that an earlier study suggests may possess an unusual number of alleles at this locus and thus may be a subject of special interest in the study of primate color vision. Direct sequencing of regions of the M/L opsin gene using feces-, blood-, and saliva-derived DNA obtained from 14 individuals yielded evidence for the presence of three functionally distinct alleles, corresponding to the most common M/L photopigment variants inferred from a physiological study of cone spectral sensitivity in captive Callicebus. PMID:20938927

Bunce, John A.; Isbell, Lynne A.; Neitz, Maureen; Bonci, Daniela; Surridge, Alison K.; Jacobs, Gerald H.; Smith, David Glenn

2011-01-01

133

Localization and characterization of val-opsin isoform-expressing cells in the brain of adult zebrafish.  

PubMed

In addition to vision, light information is used to regulate a range of animal physiology. Such nonimage-forming functions of light are mediated by nonvisual photoreceptors expressed in distinct neurons in the retina and the brain in most vertebrates. A nonvisual photoreceptor vertebrate ancient long opsin (VAL-opsin) possesses two functional isoforms in the zebrafish, encoded by valopa and valopb, which has received little attention. To delineate the neurochemical identities of valop cells and to test for colocalization of the valop isoforms, we used in situ hybridization to characterize the expression of the valop genes along with that of neurotransmitters and a neuropeptide known to be present at the sites of valop expression. Double labeling showed that the thalamic valop population coexpresses valopa and valopb. All the thalamic valop cells overlapped with a GABAergic cell mass that continues from the anterior nucleus to the intercalated thalamic nucleus. A novel valopa cell population found in the superior raphe was serotonergic in nature. A valopb cell population in the Edinger-Westphal nucleus was identified as containing thyrotropin-releasing hormone. Valopb cells localized in the hindbrain intermediate reticular formation were noncholinergic in nature (nonmotorneurons). Thus, the presence of valop cell populations in different brain regions with coexpression of neurotransmitters and neuropeptides and the colocalization of valop isoforms in the thalamic cell population indicate regulatory and functional complexity of VAL-opsin in the brain of the zebrafish. PMID:25043553

Hang, Chong Yee; Kitahashi, Takashi; Parhar, Ishwar S

2014-12-01

134

Ret 1, a cis-acting element of the rat opsin promoter, can direct gene expression in rod photoreceptors.  

PubMed

The Ret 1 element, located at -136 to -110 in the rat opsin promoter, binds developmentally regulated retinal nuclear proteins. A similar sequence is found up-stream of opsin genes, from humans to Drosophila, as well as many other photoreceptor-specific genes. The function of the Ret 1 element was tested both in vitro and in two sets of transgenic mice. A mutated Ret 1 element did not bind retinal nuclear proteins in vitro. The same mutations in an otherwise normal 1.9-kb rat opsin promoter failed to drive expression of a lacZ reporter gene in nine of 12 lines. In the three other lines, expression in photoreceptors was very faint. Four tandem copies of the Ret 1 element maintained the Ret 1 binding specificity in vitro and were able to direct expression of a lacZ transgene in photoreceptors of all nine mouse lines obtained. In two lines, expression was also detected in the ganglion cell layer and the ciliary epithelium. In three lines, a characteristic pattern of expression was found in the nervous system in addition to the normal retinal expression. These results indicate that Ret 1 can and is necessary to drive gene expression in rod photoreceptors. Furthermore, our results suggest that Ret 1-like elements may also be important in the developing nervous system. PMID:8931483

Yu, X; Leconte, L; Martinez, J A; Barnstable, C J

1996-12-01

135

Informational Lesions: Optical Perturbation of Spike Timing and Neural Synchrony Via Microbial Opsin Gene Fusions  

PubMed Central

Synchronous neural activity occurs throughout the brain in association with normal and pathological brain functions. Despite theoretical work exploring how such neural coordination might facilitate neural computation and be corrupted in disease states, it has proven difficult to test experimentally the causal role of synchrony in such phenomena. Attempts to manipulate neural synchrony often alter other features of neural activity such as firing rate. Here we evaluate a single gene which encodes for the blue-light gated cation channel channelrhodopsin-2 and the yellow-light driven chloride pump halorhodopsin from Natronobacterium pharaonis, linked by a ‘self-cleaving’ 2A peptide. This fusion enables proportional expression of both opsins, sensitizing neurons to being bi-directionally controlled with blue and yellow light, facilitating proportional optical spike insertion and deletion upon delivery of trains of precisely-timed blue and yellow light pulses. Such approaches may enable more detailed explorations of the causal role of specific features of the neural code. PMID:19753326

Han, Xue; Qian, Xiaofeng; Stern, Patrick; Chuong, Amy S.; Boyden, Edward S.

2009-01-01

136

The Transporter-Opsin-G protein-coupled receptor (TOG) Superfamily  

PubMed Central

Visual Rhodopsins (VR) are recognized members of the large and diverse family of G protein-coupled receptors (GPCRs), but their evolutionary origin and relationships to other proteins, are not known. In an earlier publication (Shlykov et al., 2012), we characterized the 4-Toulene Sulfonate Uptake Permease (TSUP) family of transmembrane proteins, showing that these 7 or 8 TMS proteins arose by intragenic duplication of a 4 TMS-encoding gene, sometimes followed by loss of a terminal TMS. In this study, we show that the TSUP, GPCR and Microbial Rhodopsin (MR) families are related to each other and to six other currently recognized transport protein families. We designate this superfamily the Transporter-Opsin-G protein-coupled receptor (TOG) Superfamily. Despite their 8 TMS origins, members of most constituent families exhibit 7 TMS topologies that are well conserved, and these arose by loss of either the N-terminal (more frequent) or the C-terminal (less frequent) TMS, depending on the family. Phylogenetic analyses revealed familial relationships within the superfamily and protein relationships within each of the nine families. The statistical analyses leading to the conclusion of homology were confirmed using HMMs, Pfam, and 3D superimpositions. Proteins functioning by dissimilar mechanisms (channels, primary active transporters, secondary active transporters, group translocators and receptors) are interspersed on a phylogenetic tree of the TOG superfamily, suggesting that changes in the transport and energy-coupling mechanisms occurred multiple times during the evolution of this superfamily. PMID:23981446

Yee, Daniel C.; Shlykov, Maksim A.; Västermark, Åke; Reddy, Vamsee S.; Arora, Sumit; Sun, Eric I.; Saier, Milton H.

2013-01-01

137

Characterization of acquired resistance in lesion-mimic transgenic potato expressing bacterio-opsin.  

PubMed

The lesion-mimic mutants of certain plants display necrotic lesions resembling those of the hypersensitive response and activate local and systemic defense responses in the absence of pathogens. We have engineered a lesion-mimic phenotype in transgenic Russet Burbank potato plants through constitutive expression of a bacterio-opsin (bO) proton pump derived from Halobacterium halobium. Transgenic potato plants exhibiting a lesion-mimic phenotype had increased levels of salicylic acid and overexpressed several pathogenesis-related messenger RNAs, all hallmarks of systemic acquired resistance (SAR). The lesion-mimic plants also displayed enhanced resistance to the US1 isolate (A1 mating type) of a fungal pathogen, Phytophthora infestans, a causal agent of late blight disease. In contrast, little resistance was observed against the US8 isolate (A2 mating type) of this pathogen. Furthermore, a majority of the transgenic plants displaying the lesion-mimic phenotype had increased susceptibility to potato virus X. The tubers of these plants were not resistant to the bacterial pathogen Erwinia carotovora. These results indicate that expression of bO can result in the activation of defense responses in transgenic potato plants and show for the first time that bO expression can confer resistance to a pathogenic fungus. However, our results also demonstrate that like SAR, this "engineered" resistance is likely to be limited to certain pathogens and particular cultivars. PMID:9204568

Abad, M S; Hakimi, S M; Kaniewski, W K; Rommens, C M; Shulaev, V; Lam, E; Shah, D M

1997-07-01

138

Io in Eclipse: Keck LWS Images and the Detection of the Forbidden SO a1 ? -> X3 ? - Rovibronic Transition at 1.7 micron.  

NASA Astrophysics Data System (ADS)

On UT 24 September 1999 we observed Io going into eclipse with the LWS (7-12 micron) system on the Keck I and, simultaneously, with NIRSPEC (1-2.5 micron) on the Keck II telescope. We obtained diffraction limited images ( ~ 0.25") at ~ 3.8, 5, 7.8 and 11.7 micron both in and out of eclipse. Loki and the Janus-Kanehikili group are clearly visible on the disk. With NIRSPEC we took spectra between 1.6 and 2.5 micron. The combined spectrum suggests that the volcano Loki contains a small ( ~ 2 km2) hot spot at ~ 960 K, a 50 km2 region at 640 K, and progressively larger areas at lower temperatures (400, 200 and 150 K), i.e., clearly an active volcano with outflowing cooling lava flows. During the eclipse a bright emission band was discovered near 1.7 micron. This band has been identified with the a1 ? -> X3 ? - forbidden transition of SO. We interpret the observed emission rate of ~ 2 x 1027 photons/s to be caused by SO molecules in the excited state directly ejected from the vent at a thermodynamic quenching temperature of ~ 1500 K, and SO/SO2 abundance ratio of ~ 0.1. The shape of the SO emission band suggests a rotational temperature of ~ 1000 K.

de Pater, I.; Roe, H. G.; Graham, J. R.; Strobel, D. F.; Bernath, P.; Marchis, F.; Macintosh, B.

2001-11-01

139

Divergent selection on opsins drives incipient speciation in Lake Victoria cichlids. PLoS Biology 4:2244–51  

E-print Network

Divergent natural selection acting on ecological traits, which also affect mate choice, is a key element of ecological speciation theory, but has not previously been demonstrated at the molecular gene level to our knowledge. Here we demonstrate parallel evolution in two cichlid genera under strong divergent selection in a gene that affects both. Strong divergent natural selection fixed opsin proteins with different predicted light absorbance properties at opposite ends of an environmental gradient. By expressing them and measuring absorbance, we show that the reciprocal fixation adapts populations to divergent light environments. The divergent evolution of the visual system coincides with divergence in male breeding coloration, consistent with incipient ecological by-product speciation.

Yohey Terai; Ole Seehausen; Takeshi Sasaki; Kazuhiko Takahashi; Shinji Mizoiri; Tohru Sugawara; Tetsu Sato; Masakatsu Watanabe; Nellie Konijnendijk; Hillary D. J. Mrosso; Hidenori Tachida; Hiroo Imai; Yoshinori Shichida; Norihiro Okada

2006-01-01

140

Structural comparison of metarhodopsin II, metarhodopsin III, and opsin based on kinetic analysis of Fourier transform infrared difference spectra.  

PubMed Central

Fourier transform infrared difference spectra were measured at 30-s intervals after a complete bleach of rhodopsin (rho) samples at 20 degrees C and three different pH values. At each pH, all of the spectra could be fit globally to two exponential decay processes. Using a branched unimolecular kinetic model in which metarhodopsin II (meta II) is hydrolyzed to opsin and retinal both directly and through metarhodopsin III (meta III), we calculated rho-->meta II, rho-->meta III, and rho-->opsin difference spectra at each of the pH values and obtained estimates for the microscopic rate constants at each pH. Because of assumptions that had to be made about the branching ratio between the meta II decay pathways, some uncertainties remain in our calculated rho-->meta III difference spectrum at each pH. Nevertheless, our data covering long time ranges, especially those obtained at pH 8, place significant new constraints on the spectrum of meta III and thus on its structure. The rho-->meta II spectrum shows no significant pH dependence over the range examined (pH 5.5-8). However, the rho-->meta III and rho-->opsin spectra each include a limited subset of pH-dependent peaks, which are mostly attributable to titratable amino acid side chains. Our observations can be used to refine an earlier conclusion that the visual pigment refolds to a rhodopsin-like conformation during meta II decay (Rothschild, K.J., J. Gillespie, and W.J. DeGrip. 1987 Biophys. J. 51:345-350). Most of this refolding occurs in the same way at pH values ranging from 5.5 to 8 and whether meta II decays to meta III or opsin. Meta II displays unique spectral perturbations that are mostly attributable to a few residues, probably including three to four aspartic or glutamic acids and an arginine. PMID:1477276

Klinger, A L; Braiman, M S

1992-01-01

141

Effect of channel mutations on the uptake and release of the retinal ligand in opsin  

PubMed Central

In the retinal binding pocket of rhodopsin, a Schiff base links the retinal ligand covalently to the Lys296 side chain. Light transforms the inverse agonist 11-cis-retinal into the agonist all-trans-retinal, leading to the active Meta II state. Crystal structures of Meta II and the active conformation of the opsin apoprotein revealed two openings of the 7-transmembrane (TM) bundle towards the hydrophobic core of the membrane, one between TM1/TM7 and one between TM5/TM6, respectively. Computational analysis revealed a putative ligand channel connecting the openings and traversing the binding pocket. Identified constrictions within the channel motivated this study of 35 rhodopsin mutants in which single amino acids lining the channel were replaced. 11-cis-retinal uptake and all-trans-retinal release were measured using UV/visible and fluorescence spectroscopy. Most mutations slow or accelerate both uptake and release, often with opposite effects. Mutations closer to the Lys296 active site show larger effects. The nucleophile hydroxylamine accelerates retinal release 80 times but the action profile of the mutants remains very similar. The data show that the mutations do not probe local channel permeability but rather affect global protein dynamics, with the focal point in the ligand pocket. We propose a model for retinal/receptor interaction in which the active receptor conformation sets the open state of the channel for 11-cis-retinal and all-trans-retinal, with positioning of the ligand at the active site as the kinetic bottleneck. Although other G protein-coupled receptors lack the covalent link to the protein, the access of ligands to their binding pocket may follow similar schemes. PMID:22431612

Piechnick, Ronny; Ritter, Eglof; Hildebrand, Peter W.; Ernst, Oliver P.; Scheerer, Patrick; Hofmann, Klaus Peter; Heck, Martin

2012-01-01

142

Possible Involvement of Cone Opsins in Distinct Photoresponses of Intrinsically Photosensitive Dermal Chromatophores in Tilapia Oreochromis niloticus  

PubMed Central

Dermal specialized pigment cells (chromatophores) are thought to be one type of extraretinal photoreceptors responsible for a wide variety of sensory tasks, including adjusting body coloration. Unlike the well-studied image-forming function in retinal photoreceptors, direct evidence characterizing the mechanism of chromatophore photoresponses is less understood, particularly at the molecular and cellular levels. In the present study, cone opsin expression was detected in tilapia caudal fin where photosensitive chromatophores exist. Single-cell RT-PCR revealed co-existence of different cone opsins within melanophores and erythrophores. By stimulating cells with six wavelengths ranging from 380 to 580 nm, we found melanophores and erythrophores showed distinct photoresponses. After exposed to light, regardless of wavelength presentation, melanophores dispersed and maintained cell shape in an expansion stage by shuttling pigment granules. Conversely, erythrophores aggregated or dispersed pigment granules when exposed to short- or middle/long-wavelength light, respectively. These results suggest that diverse molecular mechanisms and light-detecting strategies may be employed by different types of tilapia chromatophores, which are instrumental in pigment pattern formation. PMID:23940562

Chen, Shyh-Chi; Robertson, R. Meldrum; Hawryshyn, Craig W.

2013-01-01

143

Genetic basis of differential opsin gene expression in cichlid fishes K. L. CARLETON*, C. M. HOFMANN*, C. KLISZ*, Z. PATEL*, L. M. CHIRCUS*,  

E-print Network

Genetic basis of differential opsin gene expression in cichlid fishes K. L. CARLETON*, C. M studies have focused on morphology or pigmentation, adaptive vari- ation exists in many other traits rapidly it can change. Further, such diversity is important as it can lead to adaptation as well as help

Carleton, Karen L.

144

Assessing the use of genomic DNA as a predictor of the maximum absorbance wavelength of avian SWS1 opsin visual pigments.  

PubMed

Recently, in vitro mutation studies have made it possible to predict the wavelengths of maximum absorbance (lambdamax) of avian UV/violet sensitive visual pigments (SWS1) from the identity of a few key amino acid residues in the opsin gene. Given that the absorbance spectrum of a cone's visual pigment and of its pigmented oil droplet can be predicted from just the lambdamax, it may become possible to predict the entire spectral sensitivity of a bird using genetic samples from live birds or museum specimens. However, whilst this concept is attractive, it must be validated to assess the reliability of the predictions of lambdamax from opsin amino acid sequences. In this paper, we have obtained partial sequences covering three of the known spectral tuning sites in the SWS1 opsin and predicted lambdamax of all bird species for which the spectral absorbance has been measured using microspectrophotometry. Our results validate the use of molecular data from genomic DNA to predict the gross differences in lambdamax between the violet- and ultraviolet-sensitive subtypes of SWS1 opsin. Additionally, we demonstrate that a bird, the bobolink Dolichonyx oryzivorus L., can have more than one SWS1 visual pigment in its retina. PMID:19048261

Odeen, Anders; Hart, Nathan S; Håstad, Olle

2009-02-01

145

Retrograde intraciliary trafficking of opsin during the maintenance of cone-shaped photoreceptor outer segments of Xenopus laevis.  

PubMed

Photoreceptor outer segments (OSs) are essential for our visual perception, and take either rod or cone forms. The cell biological basis for the formation of rods is well established; however, the mechanism of cone formation is ill characterized. While Xenopus rods are called rods, they exhibit cone-shaped OSs during the early process of development. To visualize the dynamic reorganization of disk membranes, opsin and peripherin/rds were fused to a fluorescent protein, Dendra2, and expressed in early developing rod photoreceptors, in which OSs are still cone-shaped. Dendra2 is a fluorescent protein which can be converted from green to red irreversibly, and thus allows spatiotemporal labeling of proteins. Using a photoconversion technique, we found that disk membranes are assembled at the base of cone-shaped OSs. After incorporation into disks, however, Opsin-Dendra2 was also trafficked from old to new disk membranes, consistent with the hypothesis that retrograde trafficking of membrane components contributes to the larger disk membrane observed toward the base of the cone-shaped OS. Such retrograde trafficking is cargo-specific and was not observed for peripherin/rds-Dendra2. The trafficking is unlikely mediated by diffusion, since the disk membranes have a closed configuration, as evidenced by CNGA1 labeling of the plasma membrane. Consistent with retrograde trafficking, the axoneme, which potentially mediates retrograde intraflagellar trafficking, runs through the entire axis of OSs. This study provides an insight into the role of membrane reorganization in developing photoreceptor OSs, and proves that retrograde trafficking of membrane cargoes can occur there. PMID:24855015

Tian, Guilian; Lodowski, Kerrie H; Lee, Richard; Imanishi, Yoshikazu

2014-11-01

146

Opsin gene sequence variation across phylogenetic and population histories in Mysis (Crustacea: Mysida) does not match current light environments or visual-pigment absorbance spectra.  

PubMed

The hypothesis that selection on the opsin gene is efficient in tuning vision to the ambient light environment of an organism was assessed in 49 populations of 12 Mysis crustacean species, inhabiting arctic marine waters, coastal littoral habitats, freshwater lakes ('glacial relicts') and the deep Caspian Sea. Extensive sequence variation was found within and among taxa, but its patterns did not match expectations based on light environments, spectral sensitivity of the visual pigment measured by microspectrophotometry or the history of species and populations. The main split in the opsin gene tree was between lineages I and II, differing in six amino acids. Lineage I was present in marine and Caspian Sea species and in the North American freshwater Mysis diluviana, whereas lineage II was found in the European and circumarctic fresh- and brackish-water Mysis relicta, Mysis salemaai and Mysis segerstralei. Both lineages were present in some populations of M. salemaai and M. segerstralei. Absorbance spectra of the visual pigment in nine populations of the latter three species showed a dichotomy between lake (?(max) =554-562 nm) and brackish-water (Baltic Sea) populations (?(max) = 521-535 nm). Judged by the shape of spectra, this difference was not because of different chromophores (A2 vs. A1), but neither did it coincide with the split in the opsin tree (lineages I/II), species identity or current light environments. In all, adaptive evolution of the opsin gene in Mysis could not be demonstrated, but its sequence variation did not conform to a neutral expectation either, suggesting evolutionary constraints and/or unidentified mechanisms of spectral tuning. PMID:22429275

Audzijonyte, Asta; Pahlberg, Johan; Viljanen, Martta; Donner, Kristian; Väinölä, Risto

2012-05-01

147

Assessing the use of genomic DNA as a predictor of the maximum absorbance wavelength of avian SWS1 opsin visual pigments  

Microsoft Academic Search

Recently, in vitro mutation studies have made it possible to predict the wavelengths of maximum absorbance (?max) of avian UV\\/violet sensitive visual pigments (SWS1) from the identity of a few key amino acid residues in the opsin gene.\\u000a Given that the absorbance spectrum of a cone’s visual pigment and of its pigmented oil droplet can be predicted from just\\u000a the

Anders Ödeen; Nathan S. Hart; Olle Håstad

2009-01-01

148

Development of Lead Hammerhead Ribozyme Candidates against Human Rod Opsin mRNA for Retinal Degeneration Therapy  

PubMed Central

To identify lead candidate allele-independent hammerhead ribozymes (hhRz) for the treatment of autosomal dominant mutations in the human rod opsin (RHO) gene, we tested a series of hhRzs for potential to significantly knockdown human RHO gene expression in a human cell expression system. Multiple computational criteria were used to select target mRNA regions likely to be single stranded and accessible to hhRz annealing and cleavage. Target regions are tested for accessibility in a human cell culture expression system where the hhRz RNA and target mRNA and protein are coexpressed. The hhRz RNA is embedded in an adenoviral VAI RNA chimeric RNA of established structure and properties which are critical to the experimental paradigm. The chimeric hhRz-VAI RNA is abundantly transcribed so that the hhRzs are expected to be in great excess over substrate mRNA. HhRz-VAI traffics predominantly to the cytoplasm to colocalize with the RHO mRNA target. Colocalization is essential for second-order annealing reactions. The VAI chimera protects the hhRz RNA from degradation and provides for a long half life. With cell lines chosen for high transfection efficiency and a molar excess of hhRz plasmid over target plasmid, the conditions of this experimental paradigm are specifically designed to evaluate for regions of accessibility of the target mRNA in cellulo. Western analysis was used to measure the impact of hhRz expression on RHO protein expression. Three lead candidate hhRz designs were identified that significantly knockdown target protein expression relative to control (p < 0.05). Successful lead candidates (hhRz CUC? 266, hhRz CUC? 1411, hhRz AUA? 1414) targeted regions of human RHO mRNA that were predicted to be accessible by a bioinformatics approach, whereas regions predicted to be inaccessible supported no knockdown. The maximum opsin protein level knockdown is approximately 30% over a 48 hr paradigm of testing. These results validate a rigorous computational bioinformatics approach to detect accessible regions of target mRNAs in cellulo. The opsin knockdown effect could prove to be clinically significant when integrated over longer periods in photoreceptors. Further optimization and animal testing is the next step in this stratified RNA drug discovery program. A recently developed novel and efficient screening assay based upon expression of a dicistronic mRNA (RHO-IRES-SEAP) containing both RHO and reporter (SEAP) cDNAs was used to compare the hhRz 266 lead candidate to another agent (Rz525/hhRz485) already known to partially rescue retinal degeneration in a rodent model. Lead hhRz 266 CUC? proved more efficacious than Rz525/hhRz485 which infers viability for rescue of retinal degeneration in appropriate preclinical models of disease. PMID:19094986

Abdelmaksoud, Heba E.; Yau, Edwin H.; Zuker, Michael; Sullivan, Jack M.

2011-01-01

149

Opsin expression, physiological characterization and identification of photoreceptor cells in the dorsal rim area and main retina of the desert locust, Schistocerca gregaria.  

PubMed

For compass orientation many insects rely on the pattern of sky polarization, but some species also exploit the sky chromatic contrast. Desert locusts, Schistocerca gregaria, detect polarized light through a specialized dorsal rim area (DRA) in their compound eye. To better understand retinal mechanisms underlying visual navigation, we compared opsin expression, spectral and polarization sensitivities and response-stimulus intensity functions in the DRA and main retina of the locust. In addition to previously characterized opsins of long-wavelength-absorbing (Lo1) and blue-absorbing visual pigments (Lo2), we identified an opsin of an ultraviolet-absorbing visual pigment (LoUV). DRA photoreceptors exclusively expressed Lo2, had peak spectral sensitivities at 441 nm and showed high polarization sensitivity (PS 1.3-31.7). In contrast, ommatidia in the main eye co-expressed Lo1 and Lo2 in five photoreceptors, expressed Lo1 in two proximal photoreceptors, and Lo2 or LoUV in one distal photoreceptor. Correspondingly, we found broadband blue- and green-peaking spectral sensitivities in the main eye and one narrowly tuned UV peaking receptor. Polarization sensitivity in the main retina was low (PS 1.3-3.8). V-log I functions in the DRA were steeper than in the main retina, supporting a role in polarization vision. Desert locusts occur as two morphs, a day-active gregarious and a night-active solitarious form. In solitarious locusts, sensitivities in the main retina were generally shifted to longer wavelengths, particularly in ventral eye regions, supporting a nocturnal lifestyle at low light levels. The data support the role of the DRA in polarization vision and suggest trichromatic colour vision in the desert locust. PMID:25104757

Schmeling, Fabian; Wakakuwa, Motohiro; Tegtmeier, Jennifer; Kinoshita, Michiyo; Bockhorst, Tobias; Arikawa, Kentaro; Homberg, Uwe

2014-10-01

150

Gene duplication and spectral diversification of cone visual pigments of zebrafish.  

PubMed Central

Zebrafish is becoming a powerful animal model for the study of vision but the genomic organization and variation of its visual opsins have not been fully characterized. We show here that zebrafish has two red (LWS-1 and LWS-2), four green (RH2-1, RH2-2, RH2-3, and RH2-4), and single blue (SWS2) and ultraviolet (SWS1) opsin genes in the genome, among which LWS-2, RH2-2, and RH2-3 are novel. SWS2, LWS-1, and LWS-2 are located in tandem and RH2-1, RH2-2, RH2-3, and RH2-4 form another tandem gene cluster. The peak absorption spectra (lambdamax) of the reconstituted photopigments from the opsin cDNAs differed markedly among them: 558 nm (LWS-1), 548 nm (LWS-2), 467 nm (RH2-1), 476 nm (RH2-2), 488 nm (RH2-3), 505 nm (RH2-4), 355 nm (SWS1), 416 nm (SWS2), and 501 nm (RH1, rod opsin). The quantitative RT-PCR revealed a considerable difference among the opsin genes in the expression level in the retina. The expression of the two red opsin genes and of three green opsin genes, RH2-1, RH2-3, and RH2-4, is significantly lower than that of RH2-2, SWS1, and SWS2. These findings must contribute to our comprehensive understanding of visual capabilities of zebrafish and the evolution of the fish visual system and should become a basis of further studies on expression and developmental regulation of the opsin genes. PMID:12618404

Chinen, Akito; Hamaoka, Takanori; Yamada, Yukihiro; Kawamura, Shoji

2003-01-01

151

Opsin1-2, Gq? and arrestin levels at Limulus rhabdoms are controlled by diurnal light and a circadian clock  

PubMed Central

SUMMARY Dark and light adaptation in photoreceptors involve multiple processes including those that change protein concentrations at photosensitive membranes. Light- and dark-adaptive changes in protein levels at rhabdoms have been described in detail in white-eyed Drosophila maintained under artificial light. Here we tested whether protein levels at rhabdoms change significantly in the highly pigmented lateral eyes of wild-caught Limulus polyphemus maintained in natural diurnal illumination and whether these changes are under circadian control. We found that rhabdomeral levels of opsins (Ops1-2), the G protein activated by rhodopsin (Gq?) and arrestin change significantly from day to night and that nighttime levels of each protein at rhabdoms are significantly influenced by signals from the animal's central circadian clock. Clock input at night increases Ops1-2 and Gq? and decreases arrestin levels at rhabdoms. Clock input is also required for a rapid decrease in rhabdomeral Ops1-2 beginning at sunrise. We found further that dark adaptation during the day and the night are not equivalent. During daytime dark adaptation, when clock input is silent, the increase of Ops1-2 at rhabdoms is small and Gq? levels do not increase. However, increases in Ops1-2 and Gq? at rhabdoms are enhanced during daytime dark adaptation by treatments that elevate cAMP in photoreceptors, suggesting that the clock influences dark-adaptive increases in Ops1-2 and Gq? at Limulus rhabdoms by activating cAMP-dependent processes. The circadian regulation of Ops1-2 and Gq? levels at rhabdoms probably has a dual role: to increase retinal sensitivity at night and to protect photoreceptors from light damage during the day. PMID:23393287

Battelle, Barbara-Anne; Kempler, Karen E.; Parker, Alexander K.; Gaddie, Cristina D.

2013-01-01

152

Supplementary Figure S1. Light-associated motor responses of worms expressing (b)opsin in neurons. a, Vigorously crawling TG animals pre-incubated with 10 M 9-cis-retinal and expressing  

E-print Network

Supplementary Figure S1. Light-associated motor responses of worms expressing (b)opsin in neurons responses to light were recorded and scored. Data represent three independent experiments with 3- 10 worms) of these animals are shown. Data represent three independent experiments with 3-5 worms each. Error bars indicate S

Palczewski, Krzysztof

153

Gravitational-wave sensitivity curves  

NASA Astrophysics Data System (ADS)

There are several common conventions in use by the gravitational-wave community to describe the amplitude of sources and the sensitivity of detectors. These are frequently confused. We outline the merits of and differences between the various quantities used for parameterizing noise curves and characterizing gravitational-wave amplitudes. We conclude by producing plots that consistently compare different detectors. Similar figures can be generated on-line for general use at http://rhcole.com/apps/GWplotter.

Moore, C. J.; Cole, R. H.; Berry, C. P. L.

2015-01-01

154

Gravitational-wave sensitivity curves  

E-print Network

). The redshift of the rate of arrival of pulses for a pulsar at a distance L from the Solar- System barycentre (SSB), in the direction of the unit spatial vector pˆ induced by a GW travelling in direction of the unit vector ?ˆ is (Anholm et al., 2009) z(t, ?ˆ... of the distortion depends upon the neutron star equation of state and the stiffness of the crust, which are currently uncertain (Chamel and Haensel, 2008; Lattimer, 2012). Deformations can also be supported by internal magnetic fields (Haskell et al., 2008). Several...

Moore, C. J.; Cole, R. H.; Berry, C. P. L.

2014-12-08

155

Ablation of the X-Linked Retinitis Pigmentosa 2 (Rp2) Gene in Mice Results in Opsin Mislocalization and Photoreceptor Degeneration  

PubMed Central

Purpose. Mutations in the RP2 gene are associated with 10% to 15% of X-linked retinitis pigmentosa (XLRP), a debilitating disorder characterized by the degeneration of retinal rod and cone photoreceptors. The molecular mechanism of pathogenesis of photoreceptor degeneration in XLRP-RP2 has not been elucidated, and no treatment is currently available. This study was undertaken to investigate the pathogenesis of RP2-associated retinal degeneration. Methods. We introduced loxP sites that flank exon 2, a mutational hotspot in XLRP-RP2, in the mouse Rp2 gene. We then produced Rp2-null allele using transgenic mice that expressed Cre-recombinase under control of the ubiquitous CAG promoter. Electroretinography (ERG), histology, light microscopy, transmission electron microscopy, and immunofluorescence microscopy were performed to ascertain the effect of ablation of Rp2 on photoreceptor development, function, and protein trafficking. Results. Although no gross abnormalities were detected in the Rp2null mice, photopic (cone) and scotopic (rod) function as measured by ERG showed a gradual decline starting as early as 1 month of age. We also detected slow progressive degeneration of the photoreceptor membrane discs in the mutant retina. These defects were associated with mislocalization of cone opsins to the nuclear and synaptic layers and reduced rhodopsin content in the outer segment of mutant retina prior to the onset of photoreceptor degeneration. Conclusions. Our studies suggest that RP2 contributes to the maintenance of photoreceptor function and that cone opsin mislocalization represents an early step in XLRP caused by RP2 mutations. The Rp2null mice should serve as a useful preclinical model for testing gene- and cell-based therapies. PMID:23745007

Li, Linjing; Khan, Naheed; Hurd, Toby; Ghosh, Amiya Kumar; Cheng, Christiana; Molday, Robert; Heckenlively, John R.; Swaroop, Anand; Khanna, Hemant

2013-01-01

156

Long-wave sensitivity in deep-sea stomiid dragonfish with far-red bioluminescence: evidence for a dietary origin of the chlorophyll-derived retinal photosensitizer of Malacosteus niger.  

PubMed Central

Both residual downwelling sunlight and bioluminescence, which are the two main sources of illumination available in the deep sea, have limited wavebands concentrated around 450-500 nm. Consequently, the wavelengths of maximum absorption (lambdamax) of the vast majority of deep-sea fish visual pigments also cluster in this part of the spectrum. Three genera of deep-sea loose-jawed dragonfish (Aristostomias, Pachystomias and Malacosteus), however, in addition to the blue bioluminescence typical of most deep-sea animals, also produce far-red light (maximum emission >700 nm) from suborbital photophores. All three genera are sensitive in this part of the spectrum, to which all other animals of the deep sea are blind, potentially affording them a private waveband for illuminating prey and for interspecific communication that is immune from detection by predators and prey. Aristostomias and Pachystomias enhance their long-wave visual sensitivity by the possession of at least three visual pigments that are long-wave shifted (lambdamax values ca. 515, 550 and 590 nm) compared with those of other deep-sea fishes. Malacosteus, on the other hand, although it does possess two of these red-shifted pigments (lambdamax values ca. 520 and 540 nm), lacks the most long-wave-sensitive pigments found in the other two genera. However, it further enhances its long-wave sensitivity with a chlorophyll-derived photosensitizer within its outer segments. The fluorescence emission and excitation spectra of this pigment are very similar to spectra obtained from mesopelagic copepods, which are an important component of diet of Malacosteus, suggesting a dietary origin for this pigment. PMID:11079412

Douglas, R H; Mullineaux, C W; Partridge, J C

2000-01-01

157

Assignment of groups responsible for the "opsin shift" and light absorptions of rhodopsin and red, green, and blue iodopsins (cone pigments).  

PubMed Central

A modified structural model of rhodopsin is presented. Seven (alpha-helical) segments of 24 largely hydrophobic amino acid residues are assembled with exobilayer connecting strands into an aligned set, using the sequences of human red, green, and blue iodopsins (cone pigments) and human and bovine rod rhodopsins. (Aligned set numbering is used in this article). The inner region of the heptahelical hydrophobic domain includes one His-Glu (Asp) ion pair (red, green rod) near the retinylidene moiety in addition to an iminium ion Asp-99 pair. The negative charges posited in the "point-charge model" to cause the shift of the retinylidene iminium ion light absorption to longer wavelengths in the protein ("opsin shift") are Asp-99 (red, green rod), Glu-102 (red, green), and Glu-138 (rod). Blue iodopsin lacks both an ion pair and a counter charge to the iminium ion in the inner region, a fact that explains its absorption relative to rod rhodopsin. The spectroscopic difference between rod rhodopsin and the red/green iodopsins is due to the influence of Glu-102 in the latter. The red-green difference is due to the net effect of seven OH groups around the chromophore, all such groups being found within one helix turn of the retinylidene location. The tryptophan, which rotates as the retinylidene group isomerizes, may be Trp-142 or Trp-177. The geometric change (the rhodopsin "photoswitch") resulting from cis-trans isomerization in the first excited electronic state (S1), ultimately leads to RX (photoactivated rhodopsin, metarhodopsin II) and changes the activity of exobilayer groups, possibly causing dissociation of Lys-83 and Arg-85 from the carboxylate groups at positions 263 and 265. PMID:3422479

Kosower, E M

1988-01-01

158

Studies for Improved Gravitational Wave Sensitivity  

NASA Technical Reports Server (NTRS)

The main purpose of this study was to investigate the possible accuracy of the Laser Interferometer Space Antenna (LISA) for studying gravitational waves at frequencies below the usually quoted frequency range of 100 microHz to 1 Hz. The extended frequency range of most interest is from 3 to 100 microHz. During this work, a new source of spurious accelerations of the test masses for LISA that had been overlooked previously was identified. It is one of the main noise contributors at 100 microHz, and rises as the inverse of the frequency to become probably the largest error source at 3 microHz. The new error source is fluctuations in the charge on the test mass due to cosmic ray charging interacting with the electric fields inside the housing that carries the capacitive electrodes for sensing relative motion of the test mass with respect to the housing. Even for zero charge on the test mass, there will be electrical fields acting on each face due to work function differences between the capacitive electrodes and the test mass.

Bender, Peter L.

2003-01-01

159

ISO Guest Observer Data Analysis and LWS Instrument Team Activities  

NASA Technical Reports Server (NTRS)

The following is an interim annual report. Dr. Smith is currently on an extended TDY to the Istituto di Fisica dello Spazio Interplanetario (IFSI) at the Consilio Nazionale delle Richerche (CNR) in Rome, Italy, where he has been working on a related NASA grant in support of analysis of Infrared Space Observatory (ISO) data on star formation in Ultra Luminous Infrared Galaxies and our galaxy. Work emphasizes development of metal mesh grids for use in spacecraft, and the design and fabrication of test elements by the Naval Research Laboratory, Washington D.C. Work has progressed well, but slowly, on that program due to the departure of a key engineer. NASA has been advised of the delay, and granted a no-cost extension, whereby SAO has authorized a delay in the final report from NRL. Nevertheless NRL has continued to make progress. Two papers have been submitted to refereed journals related to this program, and a new design for mesh operating in the 20-40 micron region has been developed. Meetings continue through the summer on these items. A new technical scientist has been made a job offer and hopefully will be on board NRL shortly, although most of the present grant work is already completed. A more complete report, with copies of the submitted papers, designs, and other measures of progress, will be submitted to NASA in September when Dr. Smith returns from his current TDY.

Smith, Howard

2001-01-01

160

Cone visual pigments of aquatic mammals.  

PubMed

It has long been hypothesized that the visual systems of animals are evolutionarily adapted to their visual environment. The entrance many millions of years ago of mammals into the sea gave these new aquatic mammals completely novel visual surroundings with respect to light availability and predominant wavelengths. This study examines the cone opsins of marine mammals, hypothesizing, based on previous studies [Fasick et al. (1998) and Levenson & Dizon (2003)], that the deep-dwelling marine mammals would not have color vision because the pressure to maintain color vision in the dark monochromatic ocean environment has been relaxed. Short-wavelength-sensitive (SWS) and long-wavelength-sensitive (LWS) cone opsin genes from two orders (Cetacea and Sirenia) and an additional suborder (Pinnipedia) of aquatic mammals were amplified from genomic DNA (for SWS) and cDNA (for LWS) by PCR, cloned, and sequenced. All animals studied from the order Cetacea have SWS pseudogenes, whereas a representative from the order Sirenia has an intact SWS gene, for which the corresponding mRNA was found in the retina. One of the pinnipeds studied (harp seal) has an SWS pseudogene, while another species (harbor seal) appeared to have an intact SWS gene. However, no SWS cone opsin mRNA was found in the harbor seal retina, suggesting a promoter or splice site mutation preventing transcription of the gene. The LWS opsins from the different species were expressed in mammalian cells and reconstituted with the 11-cis-retinal chromophore in order to determine maximal absorption wavelengths (lambda(max)) for each. The deeper dwelling Cetacean species had blue shifted lambda(max) values compared to shallower-dwelling aquatic species. Taken together, these findings support the hypothesis that in the monochromatic oceanic habitat, the pressure to maintain color vision has been relaxed and mutations are retained in the SWS genes, resulting in pseudogenes. Additionally, LWS opsins are retained in the retina and, in deeper-dwelling animals, are blue shifted in lambda(max). PMID:16469194

Newman, Lucy A; Robinson, Phyllis R

2005-01-01

161

The transcription factor GTF2IRD1 regulates the topology and function of photoreceptors by modulating photoreceptor gene expression across the retina.  

PubMed

The mechanisms that specify photoreceptor cell-fate determination, especially as regards to short-wave-sensitive (S) versus medium-wave-sensitive (M) cone identity, and maintain their nature and function, are not fully understood. Here we report the importance of general transcription factor II-I repeat domain-containing protein 1 (GTF2IRD1) in maintaining M cone cell identity and function as well as rod function. In the mouse, GTF2IRD1 is expressed in cell-fate determined photoreceptors at postnatal day 10. GTF2IRD1 binds to enhancer and promoter regions in the mouse rhodopsin, M- and S-opsin genes, but regulates their expression differentially. Through interaction with the transcription factors CRX and thyroid hormone receptor ? 2, it enhances M-opsin expression, whereas it suppresses S-opsin expression; and with CRX and NRL, it enhances rhodopsin expression. In an apparent paradox, although GTF2IRD1 is widely expressed in multiple cell types across the retina, knock-out of GTF2IRD1 alters the retinal expression of only a limited number of annotated genes. Interestingly, however, the null mutation leads to altered topology of cone opsin expression in the retina, with aberrant S-opsin overexpression and M-opsin underexpression in M cones. Gtf2ird1-null mice also demonstrate abnormal M cone and rod electrophysiological responses. These findings suggest an important role for GTF2IRD1 in regulating the level and topology of rod and cone gene expression, and in maintaining normal retinal function. PMID:25392503

Masuda, Tomohiro; Zhang, Xiaodong; Berlinicke, Cindy; Wan, Jun; Yerrabelli, Anitha; Conner, Elizabeth A; Kjellstrom, Sten; Bush, Ronald; Thorgeirsson, Snorri S; Swaroop, Anand; Chen, Shiming; Zack, Donald J

2014-11-12

162

LWS Proposal to Provide Scientific Guidance and Modeling Support for the Ionospheric Mapping Mission. Part 1  

NASA Technical Reports Server (NTRS)

A data assimilation system for specifying the thermospheric density has been developed over the last several years. This system ingests GRACE/CHAMP-type in situ as well as SSULI/SSUSI remote sensing observations while making use of a physical model, the Coupled Thermosphere-Ionosphere Model (CTIM) (Fuller-Rowel1 et al., 1996). The Kalman filter was implemented as the backbone to the data assimilation system, which provides a statistically 'best' estimate as well as an estimate of the error in its state. The system was tested using a simulated thermosphere and observations. CHAMP data were then used to provide the system with a real data source. The results of this study are herein.

Richmond, Arthur D.

2005-01-01

163

Shedding light on serpent sight: the visual pigments of henophidian snakes.  

PubMed

The biologist Gordon Walls proposed his "transmutation" theory through the 1930s and the 1940s to explain cone-like morphology of rods (and vice versa) in the duplex retinas of modern-day reptiles, with snakes regarded as the epitome of his hypothesis. Despite Walls' interest, the visual system of reptiles, and in particular snakes, has been widely neglected in favor of studies of fishes and mammals. By analyzing the visual pigments of two henophidian snakes, Xenopeltis unicolor and Python regius, we show that both species express two cone opsins, an ultraviolet-sensitive short-wavelength-sensitive 1 (SWS1) (lambda(max) = 361 nm) pigment and a long-wavelength-sensitive (LWS) (lambda(max) = 550 nm) pigment, providing the potential for dichromatic color vision. They also possess rod photoreceptors which express the usual rod opsin (Rh1) pigment with a lambda(max) at 497 nm. This is the first molecular study of the visual pigments expressed in the photoreceptors of any snake species. The presence of a duplex retina and the characterization of LWS, SWS1, and Rh1 visual pigments in henophidian snakes implies that "lower" snakes do not provide support for Walls' transmutation theory, unlike some "higher" (caenophidian) snakes and other reptiles, such as geckos. More data from other snake lineages will be required to test this hypothesis further. PMID:19515920

Davies, Wayne L; Cowing, Jill A; Bowmaker, James K; Carvalho, Livia S; Gower, David J; Hunt, David M

2009-06-10

164

Modelling rock-avalanche induced impact waves: Sensitivity of the model chains to model parameters  

NASA Astrophysics Data System (ADS)

New lakes are forming in high-mountain areas all over the world due to glacier recession. Often they will be located below steep, destabilized flanks and are therefore exposed to impacts from rock-/ice-avalanches. Several events worldwide are known, where an outburst flood has been triggered by such an impact. In regions such as in the European Alps or in the Cordillera Blanca in Peru, where valley bottoms are densely populated, these far-travelling, high-magnitude events can result in major disasters. Usually natural hazards are assessed as single hazardous processes, for the above mentioned reasons, however, development of assessment and reproduction methods of the hazardous process chain for the purpose of hazard map generation have to be brought forward. A combination of physical process models have already been suggested and illustrated by means of lake outburst in the Cordillera Blanca, Peru, where on April 11th 2010 an ice-avalanche of approx. 300'000m3 triggered an impact wave, which overtopped the 22m freeboard of the rock-dam for 5 meters and caused and outburst flood which travelled 23 km to the city of Carhuaz. We here present a study, where we assessed the sensitivity of the model chain from ice-avalanche and impact wave to single parameters considering rock-/ice-avalanche modeling by RAMMS and impact wave modeling by IBER. Assumptions on the initial rock-/ice-avalanche volume, calibration of the friction parameters in RAMMS and assumptions on erosion considered in RAMMS were parameters tested regarding their influence on overtopping parameters that are crucial for outburst flood modeling. Further the transformation of the RAMMS-output (flow height and flow velocities on the shoreline of the lake) into an inflow-hydrograph for IBER was also considered a possible source of uncertainties. Overtopping time, volume, and wave height as much as mean and maximum discharge were considered decisive parameters for the outburst flood modeling and were therewith assumed dependent values. The resulting 54 runs were evaluated by an ANOVA-analysis for each dependent variable. Results show, that the model chain is able to correctly reproduce the 5m-overtopping wave. Further the dependency from the input parameters could be assessed for every dependent variable. It was e.g. shown, that RAMMS-calibration has the strongest influence on all variations, it is more crucial then the uncertainties introduced by assumptions on the initial rock-avalanche volume. The study shows, that from a hazard-assessment point of view, combinations of model chains are acceptable and permissible.

Schaub, Yvonne; Huggel, Christian

2014-05-01

165

Detection of the 62 micron Crystalline Water Ice Feature in Emission toward HH7 with ISO-LWS  

E-print Network

We report the detection of the 62 micron feature of crystalline water ice in emission towards the bow-shaped Herbig-Haro object HH 7. Significant amounts of far infrared continuum emission are also detected between 10 and 200 micron, so that Herbig-Haro objects cease to be pure emission-line objects at FIR wavelengths. The formation of crystalline water ice mantles requires grain temperatures T > 100 K at the time of mantle formation, suggesting that we are seeing material processed by the HH 7 shock front. The deduced ice mass is \\~2e-5 solar masses corresponding to a water column density N~ 1e18 cm-3; an estimate of the [H2O]/[H] abundance yields values close to the interstellar gas-phase oxygen abundance. The relatively high dust temperature and the copious amounts of gas-phase water needed to produce the observed quantity of crystalline water ice, suggest a scenario where both dissociative and non-dissociative shocks co-exist. The timescale for ice mantle formation is of the order of ~400 years, so that the importance of gas-phase water cooling as a shock diagnostic may be greatly diminished.

Sergio Molinari; Cecilia Ceccarelli; Glenn White; Paolo Saraceno; Brunella Nisini; Teresa Giannini; Emmanuel Caux

1999-06-09

166

Mon. Not. R. Astron. Soc. 323, 343361 (2001) ISO LWS observations of planetary nebula fine-structure lines  

E-print Network

are sensitive to the adopted electron density and the presence of density inhomogeneities, the strong dependence), which have been used to determine electron densities and ionic abundances for the ionized regions and densities, temperatures and gas masses for the PDRs. The strong [N iii] and [O iii] emission lines detected

Liu, Xiaowei

167

S cones: Evolution, retinal distribution, development, and spectral sensitivity.  

PubMed

S cones expressing the short wavelength-sensitive type 1 (SWS1) class of visual pigment generally form only a minority type of cone photoreceptor within the vertebrate duplex retina. Hence, their primary role is in color vision, not in high acuity vision. In mammals, S cones may be present as a constant fraction of the cones across the retina, may be restricted to certain regions of the retina or may form a gradient across the retina, and in some species, there is coexpression of SWS1 and the long wavelength-sensitive (LWS) class of pigment in many cones. During retinal development, SWS1 opsin expression generally precedes that of LWS opsin, and evidence from genetic studies indicates that the S cone pathway may be the default pathway for cone development. With the notable exception of the cartilaginous fishes, where S cones appear to be absent, they are present in representative species from all other vertebrate classes. S cone loss is not, however, uncommon; they are absent from most aquatic mammals and from some but not all nocturnal terrestrial species. The peak spectral sensitivity of S cones depends on the spectral characteristics of the pigment present. Evidence from the study of agnathans and teleost fishes indicates that the ancestral vertebrate SWS1 pigment was ultraviolet (UV) sensitive with a peak around 360 nm, but this has shifted into the violet region of the spectrum (>380 nm) on many separate occasions during vertebrate evolution. In all cases, the shift was generated by just one or a few replacements in tuning-relevant residues. Only in the avian lineage has tuning moved in the opposite direction, with the reinvention of UV-sensitive pigments. PMID:23895771

Hunt, David M; Peichl, Leo

2014-03-01

168

Phylogenetic Utility of the Major Opsin in Bees (Hymenoptera: Apoidea): A Reassessment  

E-print Network

for recovering Mesozoic divergences in insects are few. LW Rh is a member of a multigene family encoding visual and references therein). These are the Euglossini (orchid bees, 175 known species, five gen- era), Bombini, numerous genera). The corbiculate bee tribes are thought to be of Mesozoic age because a fossil meliponine

Danforth, Bryan Nicholas

169

Optical control of neuronal excitation and inhibition using a single opsin protein, ChR2  

E-print Network

The effect of electrical stimulation on neuronal membrane potential is frequency dependent. Low frequency electrical stimulation can evoke action potentials, whereas high frequency stimulation can inhibit action potential ...

Liske, Holly

170

Informational lesions: optical perturbation of spike timing and neural synchrony via microbial opsin gene fusions  

E-print Network

Synchronous neural activity occurs throughout the brain in association with normal and pathological brain functions. Despite theoretical work exploring how such neural coordination might facilitate neural computation and ...

Han, Xue

171

Principles for applying optogenetic tools derived from direct comparative analysis of microbial opsins  

Microsoft Academic Search

Diverse optogenetic tools have allowed versatile control over neural activity. Many depolarizing and hyperpolarizing tools have now been developed in multiple laboratories and tested across different preparations, presenting opportunities but also making it difficult to draw direct comparisons. This challenge has been compounded by the dependence of performance on parameters such as vector, promoter, expression time, illumination, cell type and

Joanna Mattis; Kay M Tye; Emily A Ferenczi; Charu Ramakrishnan; Daniel J O'Shea; Rohit Prakash; Lisa A Gunaydin; Minsuk Hyun; Lief E Fenno; Viviana Gradinaru; Ofer Yizhar; Karl Deisseroth

2011-01-01

172

Short-wavelength sensitive opsin (SWS1) as a new marker for vertebrate phylogenetics  

Microsoft Academic Search

BACKGROUND: Vertebrate SWS1 visual pigments mediate visual transduction in response to light at short wavelengths. Due to their importance in vision, SWS1 genes have been isolated from a surprisingly wide range of vertebrates, including lampreys, teleosts, amphibians, reptiles, birds, and mammals. The SWS1 genes exhibit many of the characteristics of genes typically targeted for phylogenetic analyses. This study investigates both

Ilke van Hazel; Francesco Santini; Johannes Müller; Belinda SW Chang

2006-01-01

173

Short-wavelength sensitive opsin (SWS1) as a new marker for vertebrate phylogenetics  

PubMed Central

Background Vertebrate SWS1 visual pigments mediate visual transduction in response to light at short wavelengths. Due to their importance in vision, SWS1 genes have been isolated from a surprisingly wide range of vertebrates, including lampreys, teleosts, amphibians, reptiles, birds, and mammals. The SWS1 genes exhibit many of the characteristics of genes typically targeted for phylogenetic analyses. This study investigates both the utility of SWS1 as a marker for inferring vertebrate phylogenetic relationships, and the characteristics of the gene that contribute to its phylogenetic utility. Results Phylogenetic analyses of vertebrate SWS1 genes produced topologies that were remarkably congruent with generally accepted hypotheses of vertebrate evolution at both higher and lower taxonomic levels. The few exceptions were generally associated with areas of poor taxonomic sampling, or relationships that have been difficult to resolve using other molecular markers. The SWS1 data set was characterized by a substantial amount of among-site rate variation, and a relatively unskewed substitution rate matrix, even when the data were partitioned into different codon sites and individual taxonomic groups. Although there were nucleotide biases in some groups at third positions, these biases were not convergent across different taxonomic groups. Conclusion Our results suggest that SWS1 may be a good marker for vertebrate phylogenetics due to the variable yet consistent patterns of sequence evolution exhibited across fairly wide taxonomic groups. This may result from constraints imposed by the functional role of SWS1 pigments in visual transduction. PMID:17107620

van Hazel, Ilke; Santini, Francesco; Müller, Johannes; Chang, Belinda SW

2006-01-01

174

Opsin switch reveals function of the ultraviolet cone in fish foraging  

PubMed Central

Although several studies have shown that ultraviolet (UV) wavelengths are important in naturally occurring, visually guided behaviours of vertebrates, the function of the UV cone in such behaviours is unknown. Here, I used thyroid hormone to transform the UV cones of young rainbow trout into blue cones, a phenomenon that occurs naturally as the animal grows, to test whether the resulting loss of UV sensitivity affected the animal's foraging performance on Daphnia magna, a prey zooplankton. The distances and angles at which prey were located (variables that are known indicators of foraging performance) were significantly reduced for UV knock-out fish compared with controls. Optical measurements and photon-catch calculations revealed that the contrast of Daphnia was greater when perceived by the visual system of control versus that of thyroid-hormone-treated fish, demonstrating that the UV cone enhanced the foraging performance of young rainbow trout. Because most juvenile fishes have UV cones and feed on zooplankton, this finding has wide implications for understanding the visual ecology of fishes. The enhanced target contrast provided by UV cones could be used by other vertebrates in various behaviours, including foraging, mate selection and communication. PMID:23222448

Novales Flamarique, Iñigo

2013-01-01

175

Gas and dust cooling along the major axis of M 33 (HerM33es). ISO/LWS [C ii] observations  

NASA Astrophysics Data System (ADS)

Aims: We aim to better understand the heating of gas by observing the prominent gas cooling line [C ii] at 158 ?m in the low-metallicity environment of the Local Group spiral galaxy M 33 on scales of 280 pc. In particular, we describe the variation of the photoelectric heating efficiency with the galactic environment. Methods: In this study, we present [C ii] observations along the major axis of M 33 using the Infrared Space Observatory in combination with Herschel continuum maps, IRAM 30 m CO 2-1, and VLA H i data to study the variation in velocity integrated intensities. The ratio of [C ii] emission over the far-infrared continuum is used as a proxy for the heating efficiency, and models of photon-dominated regions are used to study the local physical densities, far-ultraviolet radiation fields, and average column densities of the molecular clouds. Results: The heating efficiency stays constant at 0.8% in the inner 4.5 kpc radius of the galaxy, where it increases to reach values of ~3% in the outskirts at about a 6 kpc radial distance. The rise of efficiency is explained in the framework of PDR models by lowered volume densities and FUV fields for optical extinctions of only a few magnitudes at constant metallicity. For the significant fraction of H i emission stemming from PDRs and for typical pressures found in the Galactic cold neutral medium (CNM) traced by H i emission, the CNM contributes ~15% to the observed [C ii] emission in the inner 2 kpc radius of M 33. The CNM contribution remains largely undetermined in the south, while positions between radial distances of 2 and 7.3 kpc in the north of M 33 show a contribution of ~40% ± 20%. Herschel is an ESA space observatory with science instruments provided by European-led PrincipalInvestigator consortia and with important participation from NASA.Appendices are available in electronic form at http://www.aanda.org

Kramer, C.; Abreu-Vicente, J.; García-Burillo, S.; Relaño, M.; Aalto, S.; Boquien, M.; Braine, J.; Buchbender, C.; Gratier, P.; Israel, F. P.; Nikola, T.; Röllig, M.; Verley, S.; van der Werf, P.; Xilouris, E. M.

2013-05-01

176

RELAX: Detecting Relaxed Selection in a Phylogenetic Framework.  

PubMed

Relaxation of selective strength, manifested as a reduction in the efficiency or intensity of natural selection, can drive evolutionary innovation and presage lineage extinction or loss of function. Mechanisms through which selection can be relaxed range from the removal of an existing selective constraint to a reduction in effective population size. Standard methods for estimating the strength and extent of purifying or positive selection from molecular sequence data are not suitable for detecting relaxed selection, because they lack power and can mistake an increase in the intensity of positive selection for relaxation of both purifying and positive selection. Here, we present a general hypothesis testing framework (RELAX) for detecting relaxed selection in a codon-based phylogenetic framework. Given two subsets of branches in a phylogeny, RELAX can determine whether selective strength was relaxed or intensified in one of these subsets relative to the other. We establish the validity of our test via simulations and show that it can distinguish between increased positive selection and a relaxation of selective strength. We also demonstrate the power of RELAX in a variety of biological scenarios where relaxation of selection has been hypothesized or demonstrated previously. We find that obligate and facultative ?-proteobacteria endosymbionts of insects are under relaxed selection compared with their free-living relatives and obligate endosymbionts are under relaxed selection compared with facultative endosymbionts. Selective strength is also relaxed in asexual Daphnia pulex lineages, compared with sexual lineages. Endogenous, nonfunctional, bornavirus-like elements are found to be under relaxed selection compared with exogenous Borna viruses. Finally, selection on the short-wavelength sensitive, SWS1, opsin genes in echolocating and nonecholocating bats is relaxed only in lineages in which this gene underwent pseudogenization; however, selection on the functional medium/long-wavelength sensitive opsin, M/LWS1, is found to be relaxed in all echolocating bats compared with nonecholocating bats. PMID:25540451

Wertheim, Joel O; Murrell, Ben; Smith, Martin D; Kosakovsky Pond, Sergei L; Scheffler, Konrad

2015-03-01

177

From the ultrasonic to the infrared: molecular evolution and the sensory biology of bats  

PubMed Central

Great advances have been made recently in understanding the genetic basis of the sensory biology of bats. Research has focused on the molecular evolution of candidate sensory genes, genes with known functions [e.g., olfactory receptor (OR) genes] and genes identified from mutations associated with sensory deficits (e.g., blindness and deafness). For example, the FoxP2 gene, underpinning vocal behavior and sensorimotor coordination, has undergone diversification in bats, while several genes associated with audition show parallel amino acid substitutions in unrelated lineages of echolocating bats and, in some cases, in echolocating dolphins, representing a classic case of convergent molecular evolution. Vision genes encoding the photopigments rhodopsin and the long-wave sensitive opsin are functional in bats, while that encoding the short-wave sensitive opsin has lost functionality in rhinolophoid bats using high-duty cycle laryngeal echolocation, suggesting a sensory trade-off between investment in vision and echolocation. In terms of olfaction, bats appear to have a distinctive OR repertoire compared with other mammals, and a gene involved in signal transduction in the vomeronasal system has become non-functional in most bat species. Bitter taste receptors appear to have undergone a “birth-and death” evolution involving extensive gene duplication and loss, unlike genes coding for sweet and umami tastes that show conservation across most lineages but loss in vampire bats. Common vampire bats have also undergone adaptations for thermoperception, via alternative splicing resulting in the evolution of a novel heat-sensitive channel. The future for understanding the molecular basis of sensory biology is promising, with great potential for comparative genomic analyses, studies on gene regulation and expression, exploration of the role of alternative splicing in the generation of proteomic diversity, and linking genetic mechanisms to behavioral consequences. PMID:23755015

Jones, Gareth; Teeling, Emma C.; Rossiter, Stephen J.

2013-01-01

178

From the ultrasonic to the infrared: molecular evolution and the sensory biology of bats.  

PubMed

Great advances have been made recently in understanding the genetic basis of the sensory biology of bats. Research has focused on the molecular evolution of candidate sensory genes, genes with known functions [e.g., olfactory receptor (OR) genes] and genes identified from mutations associated with sensory deficits (e.g., blindness and deafness). For example, the FoxP2 gene, underpinning vocal behavior and sensorimotor coordination, has undergone diversification in bats, while several genes associated with audition show parallel amino acid substitutions in unrelated lineages of echolocating bats and, in some cases, in echolocating dolphins, representing a classic case of convergent molecular evolution. Vision genes encoding the photopigments rhodopsin and the long-wave sensitive opsin are functional in bats, while that encoding the short-wave sensitive opsin has lost functionality in rhinolophoid bats using high-duty cycle laryngeal echolocation, suggesting a sensory trade-off between investment in vision and echolocation. In terms of olfaction, bats appear to have a distinctive OR repertoire compared with other mammals, and a gene involved in signal transduction in the vomeronasal system has become non-functional in most bat species. Bitter taste receptors appear to have undergone a "birth-and death" evolution involving extensive gene duplication and loss, unlike genes coding for sweet and umami tastes that show conservation across most lineages but loss in vampire bats. Common vampire bats have also undergone adaptations for thermoperception, via alternative splicing resulting in the evolution of a novel heat-sensitive channel. The future for understanding the molecular basis of sensory biology is promising, with great potential for comparative genomic analyses, studies on gene regulation and expression, exploration of the role of alternative splicing in the generation of proteomic diversity, and linking genetic mechanisms to behavioral consequences. PMID:23755015

Jones, Gareth; Teeling, Emma C; Rossiter, Stephen J

2013-01-01

179

How parrots see their colours: novelty in the visual pigments of Platycercus elegans.  

PubMed

Intraspecific differences in retinal physiology have been demonstrated in several vertebrate taxa and are often subject to adaptive evolution. Nonetheless, such differences are currently unknown in birds, despite variations in habitat, behaviour and visual stimuli that might influence spectral sensitivity. The parrot Platycercus elegans is a species complex with extreme plumage colour differences between (and sometimes within) subspecies, making it an ideal candidate for intraspecific differences in spectral sensitivity. Here, the visual pigments of P. elegans were fully characterised through molecular sequencing of five visual opsin genes and measurement of their absorbance spectra using microspectrophotometry. Three of the genes, LWS, SW1 and SWS2, encode for proteins similar to those found in other birds; however, both the RH1 and RH2 pigments had polypeptides with carboxyl termini of different lengths and unusual properties that are unknown previously for any vertebrate visual pigment. Specifically, multiple RH2 transcripts and protein variants (short, medium and long) were identified for the first time that are generated by alternative splicing of downstream coding and non-coding exons. Our work provides the first complete characterisation of the visual pigments of a parrot, perhaps the most colourful order of birds, and moreover suggests more variability in avian eyes than hitherto considered. PMID:24259259

Knott, Ben; Davies, Wayne I L; Carvalho, Livia S; Berg, Mathew L; Buchanan, Katherine L; Bowmaker, James K; Bennett, Andrew T D; Hunt, David M

2013-12-01

180

Cone Opsin Mislocalization in Rpe65\\/ Mice: A Defect That Can Be Corrected by 11-cis Retinal  

Microsoft Academic Search

PURPOSE. In retinal degenerative diseases, rod photoreceptors typically deteriorate more rapidly than cone photoreceptors. In the Rpe65\\/ mouse, a model for Leber's congenital amau- rosis, cones degenerate much more rapidly than rods. In this model, the retinoid processing pathway in the retinal pigment epithelium is disrupted, and 11-cis retinal is not generated. This study was designed to investigate the feasibility

Baerbel Rohrer; Heather R. Lohr; Peter Humphries; T. Michael Redmond; Mathias W. Seeliger; Rosalie K. Crouch

181

Isolation and characterization of the CNBr peptides from the proteolytically derived N-terminal fragment of ovine opsin.  

PubMed Central

Ovine rhodopsin may be cleaved in situ by Staphylococcus aureus V8 proteinase into two membrane-bound fragments designated V8-L (27 000 mol.wt.) and V8-S (12 000 mol.wt.). After purification of the proteolysed complex by affinity chromatography in detergent using concanavalin A immobilized on Sepharose 4B, the two polypeptide fragments may be separated by gel-permeation chromatography on Sephadex LH-60. Digestion of the N-terminal-derived V8-L fragment with CNBr in 70% (v/v) trifluoroacetic acid resulted in a peptide mixture that could be fractionated by procedures involving gel-permeation chromatography in organic and aqueous solvents and the use of differential solubility. The complete or partial sequences of all ten peptides are reported. PMID:6224479

Brett, M; Findlay, J B

1983-01-01

182

Age-Related Deterioration of Rod Vision in Mice  

PubMed Central

Even in healthy individuals, aging leads to deterioration in visual acuity, contrast sensitivity, visual field, and dark adaptation. Little is known about the neural mechanisms that drive the age-related changes of the retina and more specifically of photoreceptors. According to one hypothesis, the age-related deterioration in rod function is due to the limited availability of 11-cis-retinal for rod pigment formation. To determine how aging affects rod photoreceptors and to test the retinoid deficiency hypothesis, we compared the morphological and functional properties of rods of adult and aged B6D2F1/J mice. We found that the number of rods and the length of their outer segments were significantly reduced in 2.5 year-old mice compared to 4 month-old animals. Aging also resulted in a 2-fold reduction in the total level of opsin in the retina. Behavioral tests revealed that scotopic visual acuity and contrast sensitivity were decreased by 2-fold in aged mice, and rod ERG recordings demonstrated reduced amplitudes of both a- and b-waves. Sensitivity of aged rods determined from single-cell recordings was also decreased by 1.5-fold, corresponding to not more than 1% free opsin in these photoreceptors, and kinetic parameters of dim flash response were not altered. Notably, the rate of rod dark adaptation was unaffected by age. Thus, our results argue against age-related deficiency of 11-cis-retinal in the B6D2F1/J mouse rod visual cycle. Surprisingly, the level of cellular dark noise was increased in aged rods providing an alternative mechanism for their desensitization. PMID:20720130

Kolesnikov, Alexander V.; Fan, Jie; Crouch, Rosalie K.; Kefalov, Vladimir J.

2010-01-01

183

Far-Infrared Spectroscopy with ISO: The Physical Conditions of the ISM in the Normal Spiral Galaxy NGC 5713  

Microsoft Academic Search

We report new ISO Long Wavelength Spectrometer (LWS) observations of the SAB(rs)bc galaxy NGC 5713. These are the first LWS results from our ``US Key Project'' on normal galaxies (Helou et al. 1996) which uses ISO LWS, CAM, and PHOT observations to study ISM properties in normal galaxies. We have obtained strong detections of the fine-structure forbidden transitions of [CII

S. Lord; S. Malhotra; G. Helou; C. A. Beichman; N. Lu; T. Lim; D. J. Hollenbach; R. H. Rubin; H. Thronson; G. Stacey; H. Dinerstein; M. W. Werner; D. A. Hunter; K. Y. Lo

1996-01-01

184

Expression of synaptic and phototransduction markers during photoreceptor development in the marmoset monkey Callithrix jacchus.  

PubMed

Marmoset photoreceptor development was studied to determine the expression sequence for synaptic, opsin, and phototransduction proteins. All markers appear first in cones within the incipient foveal center or in rods at the foveal edge. Recoverin appears in cones across 70% of the retina at fetal day (Fd) 88, indicating that it is expressed shortly after photoreceptors are generated. Synaptic markers synaptophysin, SV2, glutamate vesicular transporter 1, and CTBP2 label foveal cones at Fd 88 and cones at the retinal edge around birth. Cones and rods have distinctly different patterns of synaptic protein and opsin expression. Synaptic markers are expressed first in cones, with a considerable delay before they appear in rods at the same eccentricity. Cones express synaptic markers 2-3 weeks before they express opsin, but rods express opsin 2-4 weeks before rod synaptic marker labeling is detected. Medium/long-wavelength-selective (M&L) opsin appears in foveal cones and rod opsin in rods around the fovea at Fd 100. Very few cones expressing short-wavelength-selective (S) opsin are found in the Fd 105 fovea. Across peripheral retina, opsin appears first in rods, followed about 1 week later by M&L cone opsin. S cone opsin appears last, and all opsins reach the retinal edge by 1 week after birth. Cone transducin and rod arrestin are expressed concurrently with opsin, but cone arrestin appears slightly later. Marmoset photoreceptor development differs from that in Macaca and humans. It starts relatively late, at 56% gestation, compared with Macaca at 32% gestation. The marmoset opsin expression sequence is also different from that of either Macaca or human. PMID:19003975

Hendrickson, Anita; Troilo, David; Djajadi, Hidayat; Possin, Daniel; Springer, Alan

2009-01-10

185

Breaking the Covalent Bond—A Pigment Property that Contributes to Desensitization in Cones  

PubMed Central

Summary Retinal rod and cone pigments consist of an apoprotein, opsin, covalently linked to a chromophore, 11-cis retinal. Here we demonstrate that the formation of the covalent bond between opsin and 11-cis retinal is reversible in darkness in amphibian red cones, but essentially irreversible in red rods. This dissociation, apparently a general property of cone pigments, results in a surprisingly large amount of free opsin—about 10% of total opsin—in dark-adapted red cones. We attribute this significant level of free opsin to the low concentration of intracellular free 11-cis retinal, estimated to be only a tiny fraction (~0.1 %) of the pigment content in red cones. With its constitutive transducin-stimulating activity, the free cone opsin produces an ~2-fold desensitization in red cones, equivalent to that produced by a steady light causing 500 photoisomerizations s?1. Cone pigment dissociation therefore contributes to the sensitivity difference between rods and cones. PMID:15953417

Kefalov, Vladimir J.; Estevez, Maureen E.; Kono, Massahiro; Goletz, Patrice W.; Crouch, Rosalie K.; Cornwall, M. Carter; Yau, King-Wai

2010-01-01

186

A Rhodopsin Gene Expressed in Photoreceptor Cell R7 of the Drosophila Eye: Homologies with Other Signal-Transducing Molecules  

Microsoft Academic Search

We have isolated an opsin gene from D. melanogaster that is expressed in the ultraviolet-sensitive photoreceptor cell R7 of the Drosophila compound eye. This opsin gene con- tains no introns and encodes a 383 amino acid polypeptide that is approximately 35% homologous to the blue absorbing ninaE and Rh2 opsins, which are expressed in photoreceptor cells RI-6 and R8, respectively.

Charles S. Zuker; Craig Montell; Kevin Jones; Todd Laverty; Gerald M. Rubin

1987-01-01

187

Wavelets method for the time fractional diffusion-wave equation  

NASA Astrophysics Data System (ADS)

In this paper, an efficient and accurate computational method based on the Legendre wavelets (LWs) is proposed for solving the time fractional diffusion-wave equation (FDWE). To this end, a new fractional operational matrix (FOM) of integration for the LWs is derived. The LWs and their FOM of integration are used to transform the problem under consideration into a linear system of algebraic equations, which can be simply solved to achieve the solution of the problem. The proposed method is very convenient for solving such problems, since the initial and boundary conditions are taken into account automatically.

Heydari, M. H.; Hooshmandasl, M. R.; Maalek Ghaini, F. M.; Cattani, C.

2015-01-01

188

Fluid-Rock Interaction at the Slab-Mantle Interface: Insights from the High Pressure Rocks of the Sivrihisar Massif, Turkey  

NASA Astrophysics Data System (ADS)

Water is transported into the deep parts of the subduction system via hydrous phases such as lawsonite (lws, 11 wt.% H2O), phengite (ph, 4%), amphibole (4%), epidote-group minerals (2-4%), talc (5%), and chlorite (12%). These hydrous phases are abundant in the metabasaltic (lws eclogite and blueschist) and metasedimentary (marble, quartzite) rocks of the Sivrihisar Massif (Turkey), where they can exceed 40% modal abundance. The hydrous nature of these rocks (~5-6 wt.% H2O) likely reflects the effects of prolonged fluid-rock interaction at or near the slab-mantle interface at depths up to ~80 km for at least ~10 Ma, as indicated by the difference in 40Ar/39Ar phengite ages for lws eclogite and lws blueschist that formed from eclogite during decompression. To document the conditions, scale, and mechanism of fluid-mineral interaction at 80-45 km depth in a Late Cretaceous subduction zone, we integrate geochemical (major and trace element compositions, zoning patterns), geochronologic (40Ar/39Ar phengite), and microstructural (EBSD, XRCT) data. These techniques are applied to minerals in different textural positions (grt inclusions, fabric-forming minerals in matrix, HP veins) to investigate changes as a function of P-T conditions and to minerals in different structural positions (proximity to fault contact with overlying ultramafic unit, serpentinite lenses, lithologic contacts) to evaluate the effects of deformation and identify fluid sources and pathways. Microprobe analysis and mapping shows that lawsonite is commonly zoned in Fe, Ti, and (less common) Cr. Cr zoning is typically oscillatory and occurs in lws+grt+ph veins at lws-ecl pod margins or in blueschist located along lithologic or structural contacts. Blueschist/eclogite lws zoned in Fe typically has a Fe-poor core and Fe-richer rim, but oscillatory Fe zoning is also observed in lws veins and coarse-grained lws at pod margins. Fe-poor cores are enriched in Ti. Hourglass Ti sector zoning is common in blueschist, and can be seen in prism sections of grains cut parallel to the c-axis. Grains cut perpendicular to the c-axis show less zoning, with the exception of oscillatory rim zoning. Highly deformed lws (displaying subgrains) and lws clusters have irregular, patchy zoning patterns. Lws in retrogressed (chl+ep+lws) rocks have higher Fe content; chl-lws rocks at the margins of serpentinite lenses in the HP unit have elevated trace element content. Together, these observations indicate crystallographic and environmental control on lws composition and zoning; systematic evaluation of these characteristics and trends for different generations of lws provides information about how the fluid-rock history evolved with the P-T-time-deformation path.

Fornash, K.; Whitney, D. L.; Cosca, M. A.

2013-12-01

189

Chickens from lines artificially selected for juvenile low and high body weight differ in glucose homeostasis and pancreas physiology.  

PubMed

Artificial selection of White Plymouth Rock chickens for juvenile (day 56) body weight resulted in two divergent genetic lines: hypophagic low weight (LWS) chickens and hyperphagic obese high weight (HWS) chickens, with the latter more than 10-fold heavier than the former at selection age. A study was designed to investigate glucose regulation and pancreas physiology at selection age in LWS chickens and HWS chickens. Oral glucose tolerance and insulin sensitivity tests revealed differences in threshold sensitivity to insulin and glucose clearance rate between the lines. Results from real-time PCR showed greater pancreatic mRNA expression of four glucose regulatory genes (preproinsulin, PPI; preproglucagon, PPG; glucose transporter 2, GLUT2; and pancreatic duodenal homeobox 1, Pdx1) in LWS chickens, than HWS chickens. Histological analysis of the pancreas revealed that HWS chickens have larger pancreatic islets, less pancreatic islet mass, and more pancreatic inflammation than LWS chickens, all of which presumably contribute to impaired glucose metabolism. PMID:24614025

Sumners, L H; Zhang, W; Zhao, X; Honaker, C F; Zhang, S; Cline, M A; Siegel, P B; Gilbert, E R

2014-06-01

190

Pathophysilogical Mechanism and Treatment Strategies for Leber Congenital Amaurosis  

PubMed Central

Mutations in retinoid isomerase, RPE65, or lecithin-retinol acyltransferase (LRAT) disrupt 11-cis-retinal recycling and cause Leber congenital amaurosis (LCA), the most severe retinal dystrophy in early childhood. We used Lrat?/?, a murine model for LCA, to investigate the mechanism of rapid cone degeneration. We found that mislocalized M-opsin was degraded whereas mislocalized S-opsin accumulated in Lrat?/? cones before the onset of massive ventral/central cone degeneration. Since the ventral and central retina expresses higher levels of S-opsin than the dorsal retina in mice, our results may explain why ventral and central cones degenerate more rapidly than dorsal cones in Rpe65?/? and Lrat?/? LCA models. In addition, human blue opsin and mouse S-opsin, but not mouse M-opsin or human red/green opsins, aggregated to form cytoplasmic inclusions in transfected cells, which may explain why blue cone function is lost earlier than red/green-cone function in LCA patients. The aggregation of short-wavelength opsins likely caused rapid cone degenerations through an ER stress pathway as demonstrated in both the Lrat?/? retina and transfected cells. Based on this mechanism, we designed a new therapy of LCA by reducing ER stress. We found that systemic injection of an ER chemical chaperone, tauroursodeoxycholic acid (TUDCA), is effective in reducing ER stress, preventing apoptosis, and preserving cones in Lrat?/? mice. PMID:24664772

Zhang, Tao

2014-01-01

191

Adaptive evolution of color vision as seen through the eyes of butterflies Prudic, and Adriana D. Briscoe  

E-print Network

and exhibit significant dN /dS >1. Homology modeling of the full-length Limenitis arthemis astyanax L opsin epimicrospectrophotometry on the eyes of five Limenitis butterfly species and found a 31-nm range of variation in the max values of the L-sensitive photopig- ments (514­545 nm). We cloned partial Limenitis L opsin gene

192

Pathophysilogical mechanism and treatment strategies for Leber congenital amaurosis.  

PubMed

Mutations in retinoid isomerase, RPE65, or lecithin-retinol acyltransferase (LRAT) disrupt 11-cis-retinal recycling and cause Leber congenital amaurosis (LCA), the most severe retinal dystrophy in early childhood. We used Lrat (-/-), a murine model for LCA, to investigate the mechanism of rapid cone degeneration. We found that mislocalized M-opsin was degraded whereas mislocalized S-opsin accumulated in Lrat (-/-) cones before the onset of massive ventral/central cone degeneration. Since the ventral and central retina expresses higher levels of S-opsin than the dorsal retina in mice, our results may explain why ventral and central cones degenerate more rapidly than dorsal cones in Rpe65 (-/-) and Lrat (-/-) LCA models. In addition, human blue opsin and mouse S-opsin, but not mouse M-opsin or human red/green opsins, aggregated to form cytoplasmic inclusions in transfected cells, which may explain why blue cone function is lost earlier than red/green-cone function in LCA patients. The aggregation of short-wavelength opsins likely caused rapid cone degenerations through an ER stress pathway as demonstrated in both the Lrat (-/-) retina and transfected cells. Based on this mechanism, we designed a new therapy of LCA by reducing ER stress. We found that systemic injection of an ER chemical chaperone, tauroursodeoxycholic acid (TUDCA), is effective in reducing ER stress, preventing apoptosis, and preserving cones in Lrat (-/-) mice. PMID:24664772

Fu, Yingbin; Zhang, Tao

2014-01-01

193

www.sciencemag.org SCIENCE VOL 344 25 APRIL 2014 369 PERSPECTIVES  

E-print Network

for use in optogenetics. Through heterologous expression of light-sensitive opsins, researchers can con. Optogenetics thus provides precise neuronal control that can resolve highly complex neu- ronal activity opsins have limited functionality for optogenetics; for example, their ion conductance and ion

Schnitzer, Mark

194

Bat eyes have ultraviolet-sensitive cone photoreceptors.  

PubMed

Mammalian retinae have rod photoreceptors for night vision and cone photoreceptors for daylight and colour vision. For colour discrimination, most mammals possess two cone populations with two visual pigments (opsins) that have absorption maxima at short wavelengths (blue or ultraviolet light) and long wavelengths (green or red light). Microchiropteran bats, which use echolocation to navigate and forage in complete darkness, have long been considered to have pure rod retinae. Here we use opsin immunohistochemistry to show that two phyllostomid microbats, Glossophaga soricina and Carollia perspicillata, possess a significant population of cones and express two cone opsins, a shortwave-sensitive (S) opsin and a longwave-sensitive (L) opsin. A substantial population of cones expresses S opsin exclusively, whereas the other cones mostly coexpress L and S opsin. S opsin gene analysis suggests ultraviolet (UV, wavelengths <400 nm) sensitivity, and corneal electroretinogram recordings reveal an elevated sensitivity to UV light which is mediated by an S cone visual pigment. Therefore bats have retained the ancestral UV tuning of the S cone pigment. We conclude that bats have the prerequisite for daylight vision, dichromatic colour vision, and UV vision. For bats, the UV-sensitive cones may be advantageous for visual orientation at twilight, predator avoidance, and detection of UV-reflecting flowers for those that feed on nectar. PMID:19636375

Müller, Brigitte; Glösmann, Martin; Peichl, Leo; Knop, Gabriel C; Hagemann, Cornelia; Ammermüller, Josef

2009-01-01

195

Far-infrared spectroscopy of the giant planets: measurements of ammonia and phosphine at Jupiter and Saturn and the continuum of Neptune  

Microsoft Academic Search

We detected rotational transition features of ammonia and phosphine in the far-infrared spectra of Jupiter and Saturn and measured the far-infrared continuum of Neptune with high photometric accuracy. These observations were made with the long-wavelength spectrometer (LWS) aboard the infrared space observatory (ISO). The LWS covered the wavelength region between 43 and 197 mum (51-233 cm-1) with both medium and

M. J. Burgdorf; G. S. Orton; T. Encrenaz; G. R. Davis; E. Lellouch; S. D. Sidher; B. M. Swinyard

2004-01-01

196

Far-infrared spectroscopy of the giant planets: measurements of ammonia and phosphine at Jupiter and Saturn and the continuum of Neptune  

Microsoft Academic Search

We detected rotational transition features of ammonia and phosphine in the far-infrared spectra of Jupiter and Saturn and measured the far-infrared continuum of Neptune with high photometric accuracy. These observations were made with the long-wavelength spectrometer (LWS) aboard the infrared space observatory (ISO). The LWS covered the wavelength region between 43 and 197 ?m (51–233 cm?1) with both medium and

M. J. Burgdorf; G. S. Orton; T. Encrenaz; G. R. Davis; E. Lellouch; S. D. Sidher; B. M. Swinyard

2004-01-01

197

Chlamyrhodopsin represents a new type of sensory photoreceptor.  

PubMed Central

In order to find optimal light conditions for photosynthetic growth, the green alga Chlamydomonas uses a visual system. An optical device, a rhodopsin photoreceptor and an electrical signal transduction chain that mediates between photoreceptor and flagella comprise this system. Here we present an improved strategy for the preparation of eyespot membranes. These membranes contain a retinal binding protein, which has been proposed to be the apoprotein of the phototaxis receptor. The retinal binding protein, which we named chlamyopsin, was purified and opsin-specific antibodies were raised. Using these antibodies, the opsin was localized in the eyespot region of whole cells during growth and cell division. The opsin cDNA was purified and sequenced. The sequence reveals that chlamyopsin is not a typical seven helix receptor. It shows some homology to invertebrate opsins but not to opsins from halobacteria. It contains many polar and charged residues and might function as a light-gated ion channel complex. It is likely that this lower plant rhodopsin diverged from animal opsins early in opsin evolution. Images PMID:8846778

Deininger, W; Kröger, P; Hegemann, U; Lottspeich, F; Hegemann, P

1995-01-01

198

Photoreceptor subtype specification: from flies to humans.  

PubMed

Multiple cell types often differentiate from a pluripotent cell. These cells may then further diversify as distinct subtypes. The visual system provides an ideal model for studying subtype specification as various photoreceptors acquire different functions based on the type of opsin they express. Opsin expression is mostly controlled through transcriptional mechanisms that are evolutionary conserved from Drosophila to humans. In addition, it appears that, from a "default" developmental state, distinct "acquired" photoreceptor states develop upon receiving intrinsic or extrinsic signals. This review discusses factors involved in opsin gene regulation and how their integration may explain how subtype specificity is achieved. PMID:11735387

Cook, T; Desplan, C

2001-12-01

199

Number and Distribution of Mouse Retinal Cone Photoreceptors: Differences between an Albino (Swiss) and a Pigmented (C57/BL6) Strain  

PubMed Central

We purpose here to analyze and compare the population and topography of cone photoreceptors in two mouse strains using automated routines, and to design a method of retinal sampling for their accurate manual quantification. In whole-mounted retinas from pigmented C57/BL6 and albino Swiss mice, the longwave-sensitive (L) and the shortwave-sensitive (S) opsins were immunodetected to analyze the population of each cone type. In another group of retinas both opsins were detected with the same fluorophore to quantify all cones. In a third set of retinas, L-opsin and Brn3a were immunodetected to determine whether L-opsin+cones and retinal ganglion cells (RGCs) have a parallel distribution. Cones and RGCs were automatically quantified and their topography illustrated with isodensity maps. Our results show that pigmented mice have a significantly higher number of total cones (all-cones) and of L-opsin+cones than albinos which, in turn, have a higher population of S-opsin+cones. In pigmented animals 40% of cones are dual (cones that express both opsins), 34% genuine-L (cones that only express the L-opsin), and 26% genuine-S (cones that only express the S-opsin). In albinos, 23% of cones are genuine-S and the proportion of dual cones increases to 76% at the expense of genuine-L cones. In both strains, L-opsin+cones are denser in the central than peripheral retina, and all-cones density increases dorso-ventrally. In pigmented animals S-opsin+cones are scarce in the dorsal retina and very numerous in the ventral retina, being densest in its nasal aspect. In albinos, S-opsin+cones are abundant in the dorsal retina, although their highest densities are also ventral. Based on the densities of each cone population, we propose a sampling method to manually quantify and infer their total population. In conclusion, these data provide the basis to study cone degeneration and its prevention in pathologic conditions. PMID:25029531

Jiménez-López, Manuel; Alburquerque-Béjar, Juan J.; Nieto-López, Leticia; García-Ayuso, Diego; Villegas-Pérez, Maria P.; Vidal-Sanz, Manuel; Agudo-Barriuso, Marta

2014-01-01

200

research highlights 120 | VOL.6 NO.2 | FEBRUARY 2009 | nature methods  

E-print Network

.Projectsdesignedtoimprovemembrane targeting and to apply a composite of opsins, including the red light­responsive channel- rhodopsin from on battery life for devices that provide chronic deep brain stimulation (for example,treatment of Parkinson

Cai, Long

201

The photochemical determinants of color vision  

PubMed Central

The evolution of a variety of important chromophore-dependent biological processes, including microbial light sensing and mammalian color vision, relies on protein modifications that alter the spectral characteristics of a bound chromophore. Three different color opsins share the same chromophore, but have three distinct absorptions that together cover the entire visible spectrum, giving rise to trichromatic vision. The influence of opsins on the absorbance of the chromophore has been studied through methods such as model compounds, opsin mutagenesis, and computational modeling. The recent development of rhodopsin mimic that uses small soluble proteins to recapitulate the binding and wavelength tuning of the native opsins provides a new platform for studying protein-regulated spectral tuning. The ability to achieve far-red shifted absorption in the rhodopsin mimic system was attributed to a combination of the lack of a counteranion proximal to the iminium, and a uniformly neutral electrostatic environment surrounding the chromophore. PMID:24323922

Wang, Wenjing; Geiger, James H; Borhan, Babak

2014-01-01

202

Erx, a Novel Retina-Specific Homeodomain Transcription Factor, Can Interact with Ret 1\\/PCEI Sites  

Microsoft Academic Search

Our previous studies on the transcriptional regulation of rod opsin gene expression had defined a strikingly conserved element, Ret 1\\/PCEI, present in the upstream regulatory regions of opsin and other photoreceptor-specific genes. This element interacts with a 40 kDa, developmentally regulated, retina-specific protein. In this study we report the cloning of the novel retina-specific homeodomain protein Erx. Erx contains a

Julian A. Martinez; Colin J. Barnstable

1998-01-01

203

Ultraviolet photopigment sensitivity and ocular media transmittance in gulls, with an evolutionary perspective  

Microsoft Academic Search

Gulls (Laridae excluding Sternidae) appear to be the only shorebirds (Charadriiformes) that have a short wavelength sensitive\\u000a type 1 (SWS1) cone pigment opsin tuned to ultraviolet (UV) instead of violet. However, the apparent UV-sensitivity has only\\u000a been inferred indirectly, via the interpretation that the presence of cysteine at the key amino acid position 90 in the SWS1\\u000a opsin confers UV

Olle Håstad; Julian C. Partridge; Anders Ödeen

2009-01-01

204

Human Cone Visual Pigment Deletions Spare Sufficient Photoreceptors to Warrant Gene Therapy  

PubMed Central

Abstract Human X-linked blue-cone monochromacy (BCM), a disabling congenital visual disorder of cone photoreceptors, is a candidate disease for gene augmentation therapy. BCM is caused by either mutations in the red (OPN1LW) and green (OPN1MW) cone photoreceptor opsin gene array or large deletions encompassing portions of the gene array and upstream regulatory sequences that would predict a lack of red or green opsin expression. The fate of opsin-deficient cone cells is unknown. We know that rod opsin null mutant mice show rapid postnatal death of rod photoreceptors. Using in vivo histology with high-resolution retinal imaging, we studied a cohort of 20 BCM patients (age range 5–58) with large deletions in the red/green opsin gene array. Already in the first years of life, retinal structure was not normal: there was partial loss of photoreceptors across the central retina. Remaining cone cells had detectable outer segments that were abnormally shortened. Adaptive optics imaging confirmed the existence of inner segments at a spatial density greater than that expected for the residual blue cones. The evidence indicates that human cones in patients with deletions in the red/green opsin gene array can survive in reduced numbers with limited outer segment material, suggesting potential value of gene therapy for BCM. PMID:24067079

Cideciyan, Artur V.; Hufnagel, Robert B.; Carroll, Joseph; Sumaroka, Alexander; Luo, Xunda; Schwartz, Sharon B.; Dubra, Alfredo; Land, Megan; Michaelides, Michel; Gardner, Jessica C.; Hardcastle, Alison J.; Moore, Anthony T.; Sisk, Robert A.; Ahmed, Zubair M.; Kohl, Susanne

2013-01-01

205

Encephalic photoreception and phototactic response in the troglobiont Somalian blind cavefish Phreatichthys andruzzii  

PubMed Central

SUMMARY Many physiological and behavioural responses to changes in environmental lighting conditions are mediated by extraocular photoreceptors. Here we investigate encephalic photoreception in Phreatichthys andruzzii, a typical cave-dwelling fish showing an extreme phenotype with complete anophthalmy and a reduction in size of associated brain structures. We firstly identified two P. andruzzii photopigments, orthologues of rod opsin and exo-rod opsin. In vitro, both opsins serve as light-absorbing photopigments with ?max around 500 nm when reconstituted with an A1 chromophore. When corrected for the summed absorption from the skin and skull, the spectral sensitivity profiles shifted to longer wavelengths (rod opsin: 521 nm; exo-rod opsin: 520 nm). We next explored the involvement of both opsins in the negative phototaxis reported for this species. A comparison of the spectral sensitivity of the photophobic response with the putative A2 absorbance spectra corrected for skin/skull absorbance indicates that the A2 versions of either or both of these pigments could explain the observed behavioural spectral sensitivity. PMID:22837464

Tarttelin, Emma E.; Frigato, Elena; Bellingham, James; Di Rosa, Viviana; Berti, Roberto; Foulkes, Nicholas S.; Lucas, Robert J.; Bertolucci, Cristiano

2012-01-01

206

Spectral tuning in salamander visual pigments studied with dihydroretinal chromophores.  

PubMed Central

In visual pigments, opsin proteins regulate the spectral absorption of a retinal chromophore by mechanisms that change the energy level of the excited electronic state relative to the ground state. We have studied these mechanisms by using photocurrent recording to measure the spectral sensitivities of individual red rods and red (long-wavelength-sensitive) and blue (short-wavelength-sensitive) cones of salamander before and after replacing the native 3-dehydro 11-cis retinal chromophore with retinal analogs: 11-cis retinal, 3-dehydro 9-cis retinal, 9-cis retinal, and 5,6-dihydro 9-cis retinal. The protonated Schiff's bases of analogs with unsaturated bonds in the ring had broader spectra than the same chromophores bound to opsins. Saturation of the bonds in the ring reduced the spectral bandwidths of the protonated Schiff's bases and the opsin-bound chromophores and made them similar to each other. This indicates that torsion of the ring produces spectral broadening and that torsion is limited by opsin. Saturating the 5,6 double bond in retinal reduced the perturbation of the chromophore by opsin in red and in blue cones but not in red rods. Thus an interaction between opsin and the chromophoric ring shifts the spectral maxima of the red and blue cone pigments, but not that of the red rod pigment. PMID:10423447

Makino, C L; Groesbeek, M; Lugtenburg, J; Baylor, D A

1999-01-01

207

The Living With a Star Program Space Environment Testbed  

NASA Technical Reports Server (NTRS)

This viewgraph presentation describes the objective, approach, and scope of the Living With a Star (LWS) program at the Marshall Space Flight Center. Scientists involved in the project seek to refine the understanding of space weather and the role of solar variability in terrestrial climate change. Research and the development of improved analytic methods have led to increased predictive capabilities and the improvement of environment specification models. Specifically, the Space Environment Testbed (SET) project of LWS is responsible for the implementation of improved engineering approaches to observing solar effects on climate change. This responsibility includes technology development, ground test protocol development, and the development of a technology application model/engineering tool.

Barth, Janet; Day, John H. (Technical Monitor)

2001-01-01

208

Application of artificial neural networks for damage indices classification with the use of Lamb waves for the aerospace structures.  

E-print Network

of guided waves. Aircraft structural elements have to stand high safety standards, therefore an inc to a complex structure, for instance, an aircraft component with riveted joints and stringers characterized in the literature. In this paper, comparison a number of damage indices applied to LWs testing in aircraft aluminum

209

Numerical Analysis of Effects of Large Wood Structures on Channel Morphology and Fish Habitat Suitability in a Southern U.S. Sandy Creek  

Technology Transfer Automated Retrieval System (TEKTRAN)

A depth-averaged two-dimensional model was applied to simulate the effect of large wood structures (LWS) on flow, sediment transport, bed change, and fish habitat in a deeply-incised sharp bend in the Little Topashaw Creek, North Central Mississippi. The hydrodynamic simulation showed that the flow ...

210

Numerical analysis of effects of large wood structures on channel morphology and fish habitat suitability in Little Topashaw Creek  

Technology Transfer Automated Retrieval System (TEKTRAN)

A depth-averaged two dimensional (2D) model has been applied to simulate the effect of large wood structures (LWS) on flow, sediment transport, bed change, and fish habitat suitability in a deeply-incised sharp bend in the Little Topashaw Creek, North Central Mississippi. The hydrodynamic simulation...

211

Keck long-wavelength spectrometer  

NASA Astrophysics Data System (ADS)

UCSD's IR astronomy group is building an imaging mid-IR spectrometer for the Keck Telescope. This instrument, the Long-Wavelength Spectrometer (LWS), is built around a 96 X 96 element, Si:As impurity band conduction array built by GenCorp Aerojet Electronics Systems Division. The LWS has low and moderate spectroscopy modes with nominal spectral resolutions of R (equals (lambda) /(Delta) (lambda) ) equals 100 and 1400 respectively, operating in the 10 micrometers (second order) and 20 micrometers (first order) ground- based atmospheric spectral windows. The LWS is also capable of direct imaging from 5 micrometers to 27 micrometers through a selection of 16 filters. For each of the spectroscopic modes and the direct imaging mode, the plate scale is 0.12 arcsec/pixel, which Nyquist samples the telescope's diffraction pattern at 10 micrometers . Because of the large light gathering power of the Keck Telescope and it's small diffraction pattern, the LWS will have unparalleled point source sensitivity, making it the premiere instrument for extragalactic and general faint-source mid-IR spectroscopy.

Jones, Barbara; Puetter, Richard C.

1993-10-01

212

The molecular genetics and evolution of red and green color vision in vertebrates.  

PubMed Central

To better understand the evolution of red-green color vision in vertebrates, we inferred the amino acid sequences of the ancestral pigments of 11 selected visual pigments: the LWS pigments of cave fish (Astyanax fasciatus), frog (Xenopus laevis), chicken (Gallus gallus), chameleon (Anolis carolinensis), goat (Capra hircus), and human (Homo sapiens);and the MWS pigments of cave fish, gecko (Gekko gekko), mouse (Mus musculus), squirrel (Sciurus carolinensis), and human. We constructed these ancestral pigments by introducing the necessary mutations into contemporary pigments and evaluated their absorption spectra using an in vitro assay. The results show that the common ancestor of vertebrates and most other ancestors had LWS pigments. Multiple regression analyses of ancestral and contemporary MWS and LWS pigments show that single mutations S180A, H197Y, Y277F, T285A, A308S, and double mutations S180A/H197Y shift the lambda(max) of the pigments by -7, -28, -8, -15, -27, and 11 nm, respectively. It is most likely that this "five-sites" rule is the molecular basis of spectral tuning in the MWS and LWS pigments during vertebrate evolution. PMID:11545071

Yokoyama, S; Radlwimmer, F B

2001-01-01

213

The molecular genetics and evolution of red and green color vision in vertebrates.  

PubMed

To better understand the evolution of red-green color vision in vertebrates, we inferred the amino acid sequences of the ancestral pigments of 11 selected visual pigments: the LWS pigments of cave fish (Astyanax fasciatus), frog (Xenopus laevis), chicken (Gallus gallus), chameleon (Anolis carolinensis), goat (Capra hircus), and human (Homo sapiens);and the MWS pigments of cave fish, gecko (Gekko gekko), mouse (Mus musculus), squirrel (Sciurus carolinensis), and human. We constructed these ancestral pigments by introducing the necessary mutations into contemporary pigments and evaluated their absorption spectra using an in vitro assay. The results show that the common ancestor of vertebrates and most other ancestors had LWS pigments. Multiple regression analyses of ancestral and contemporary MWS and LWS pigments show that single mutations S180A, H197Y, Y277F, T285A, A308S, and double mutations S180A/H197Y shift the lambda(max) of the pigments by -7, -28, -8, -15, -27, and 11 nm, respectively. It is most likely that this "five-sites" rule is the molecular basis of spectral tuning in the MWS and LWS pigments during vertebrate evolution. PMID:11545071

Yokoyama, S; Radlwimmer, F B

2001-08-01

214

Generation of sub-three-cycle, 16 TW light pulses by using noncollinear optical parametric  

E-print Network

an efficient con- version, to ensure a good spatial signal profile, to reach high pulse contrast we call Light-Wave-Synthesizer-20 (LWS-20). It gen- erates 7.9 fs, 130 mJ 16 TW pulses at an 805 nmGeneration of sub-three-cycle, 16 TW light pulses by using noncollinear optical parametric chirped-pulse

215

The contribution of IFSI (Istituto di Fisica dello Spazio Interplanetario) to the ISO project  

NASA Astrophysics Data System (ADS)

IFSI efforts in the development of the long-wavelength spectrometer (LWS) for the IR Space Observatory (ISO), scheduled for launch in 1993, are briefly reviewed. The LWS operates at 45-200 microns with resolution of about 200 (using a grating alone) or about 10,000 (using a grating with one of two Fabry-Perot etalons). Other LWS parameters include FOV 1.5 arcmin, sensitivity 1 x 10 to the -16th W/sq m, and SNR = 10 for a 10-sec high-resolution observation. Particular attention is given to the LWS data-processing unit (DPU), based on an 80C86 CPU and providing telecommand reception at 80 bps, data telemetry at 32,000 bps, detector sampling once every 0.5 msec, control of gratings and etalons, and continuous self-maintenance. Since the orbit of ISO exposes it to the earth radiation belts for about 2 h/day, the DPU is doubled, and the software is completely relocatable. An overview of the software design and a description of the low-noise dc-dc converter are included.

Orfei, R.; Baldetti, P.; Ceccarelli, C.; Cerulli, P.; Lorenzetti, D.

1990-02-01

216

http://shm.sagepub.com/ Structural Health Monitoring  

E-print Network

are to be monitored. LWs can be used in active SHM schemes, where a network of sensors­actuators is capable of detecting and locat- ing damage as well as, in some cases, estimating its severity. In SHM a sensor­actuator- posed of six PVDF interdigital transducers with curved fingers, each of them generating a divergent beam

217

Optogenetics for Retinal Disorders  

PubMed Central

Optogenetics is the use of genetic methods combined with optical technology to achieve gain or loss of function within neuronal circuits. The field of optogenetics has been rapidly expanding in efforts to restore visual function to blinding diseases such as retinitis pigmentosa (RP). Most work in the field includes a group of light-sensitive retinaldehyde-binding proteins known as opsins. Opsins couple photon absorption to molecular signaling chains that control cellular ion currents. Targeting of opsin genes to surviving retinal cells is fundamental to the success of optogenetic therapy. Viral delivery, primarily adeno-associated virus, using intravitreal injection for inner retinal cells and subretinal injection for outer retinal cells, has proven successful in many models. Challenges in bioengineering remain for optogenetics including relative insensitivity of opsins to physiologic light levels of stimulation and difficulty with viral delivery in primate models. However, targeting optogenetic therapy may present an even greater challenge. Neural and glial remodeling seen in advanced stages of RP result in reorganization of remaining neural retina, and optogenetic therapy may not yield functional results. Remodeling also poses a challenge to the selection of cellular targets, with bipolar, amacrine and ganglion cells all playing distinct physiologic roles, and affected by remodeling differently. Although optogenetics has drawn closer to clinical utility, advances in opsin engineering, therapeutic targeting and ultimately in molecular inhibition of remodeling will play critical roles in the continued clinical advancement of optogenetic therapy.

Henriksen, Bradley S.; Marc, Robert E.; Bernstein, Paul S.

2014-01-01

218

An explicit signature of balancing selection for color-vision variation in new world monkeys.  

PubMed

Color vision is an important characteristic of primates and, intriguingly, Neotropical monkeys are highly polymorphic for this trait. Recent field studies have challenged the conventional view that trichromatic color vision is more adaptive than dichromatic color vision. No study has investigated the pattern of genetic variation in the long to middle wavelength-sensitive (L-M or red-green) opsin gene as compared with that of other genomic regions (neutral references) in wild populations of New World monkeys to look for the signature of natural selection. Here, we report such a study conducted on spider monkeys and capuchin monkeys inhabiting Santa Rosa National Park, Costa Rica. The nucleotide sequence of the L-M opsin gene was more polymorphic than the sequences of the neutral references, although the opsin-gene sequences were not more divergent between the two species than were the sequences of the neutral references. In a coalescence simulation that took into account the observed nucleotide diversity of the neutral references, the Tajima's D value of the L-M opsin gene deviated significantly in a positive direction from the expected range. These results are the first to statistically demonstrate balancing selection acting on the polymorphic L-M opsin gene of New World monkeys. Taking the results of behavioral and genetic studies together, the balancing selection we detected may indicate that coexistence of different color-vision types in the same population, also characteristic of humans, is adaptive. PMID:19861643

Hiwatashi, Tomohide; Okabe, Yugo; Tsutsui, Toko; Hiramatsu, Chihiro; Melin, Amanda D; Oota, Hiroki; Schaffner, Colleen M; Aureli, Filippo; Fedigan, Linda M; Innan, Hideki; Kawamura, Shoji

2010-02-01

219

Evidence for a phototransduction cascade in an early brachiopod embryo.  

PubMed

Bilaterian photoreceptor cells are characterized by the expression of opsins, signal transduction genes, and ion channels, which together facilitate behavioral responses to light. We have previously identified a ciliary opsin gene from the brachiopod Terebratalia transversa, whose expression in gastrula stage embryos coincides with a photoresponse behavior, suggesting the presence of a functional phototransduction system in these early embryos. To further evaluate the potential for light reception in these embryos, we surveyed transcriptome data to identify phototransduction genes and evaluated their expression. In addition to the previously described ciliary opsin gene, we have identified two Go-class opsins that are also expressed in gastrula stage embryos. Representative members from all classes of G?-protein genes were also expressed, with a G?12-class gene being localized in the same anterior ectodermal domain as the opsin transcripts. Both CNG-class and TRP-class ion channels were expressed in the gastrula stage embryos, as were GRK and arrestin genes, which are associated with inhibition of rhodopsin activity. Taken together, these data support the presence of a functional phototransduction system in the early brachiopod embryo. PMID:23630970

Passamaneck, Yale J; Martindale, Mark Q

2013-07-01

220

Transgenic mice with a rhodopsin mutation (Pro23His): a mouse model of autosomal dominant retinitis pigmentosa.  

PubMed

We inserted into the germline of mice either a mutant or wild-type allele from a patient with retinitis pigmentosa and a missense mutation (P23H) in the rhodopsin gene. All three lines of transgenic mice with the mutant allele developed photoreceptor degeneration; the one with the least severe retinal photoreceptor degeneration had the lowest transgene expression, which was one-sixth the level of endogenous murine rod opsin. Of two lines of mice with the wild-type allele, one expressed approximately equal amounts of transgenic and murine opsin and maintained normal retinal function and structure. The other expressed approximately 5 times more transgenic than murine opsin and developed a retinal degeneration similar to that found in mice carrying a mutant allele, presumably due to the overexpression of this protein. Our findings help to establish the pathogenicity of mutant human P23H rod opsin and suggest that overexpression of wild-type human rod opsin leads to a remarkably similar photoreceptor degeneration. PMID:1418997

Olsson, J E; Gordon, J W; Pawlyk, B S; Roof, D; Hayes, A; Molday, R S; Mukai, S; Cowley, G S; Berson, E L; Dryja, T P

1992-11-01

221

A Cluster Randomized Trial to Evaluate a Health Education Programme “Living with Sun at School”  

PubMed Central

Over-exposure to sunlight increases the risk of skin cancers, particularly when exposure occurs during childhood. School teachers can play an active role in providing an education programme that can help prevent this. “Living with the Sun,” (LWS) is a sun safety education program for school children based on a handy guide for classroom activities designed to improve children’s knowledge, but moreover to positively modify their sun safety attitudes and behaviours. The goal of our study was to determine the effectiveness of this programme by examining children’s knowledge, attitude and sun exposure behaviours prior to and after the completion of the programme. We carried out a cluster randomised trial in which the classes were randomly assigned to one of two groups; one using the LWS programme and another that didn’t, serving as the control. Data was collected before completion of the programme and an additional three times in the year after completion. The 70 participating classes (1,365 schoolchildren) were distributed throughout France. Statistical analysis confirmed that knowledge of sun risk increased significantly in the LWS classes (p < 0.001). Both groups positively changed their attitudes when considering the best sun protection, but the LWS group proved to consistently be more convinced (p = 0.04). After the summer holidays, differences between the two groups decreased throughout the year but stayed globally significant. We also observed some significant behaviour modification during the holidays. For instance, the LWS group applied sunscreen more frequently than the control group, and were more likely to wear a hat (72% versus 59%) and use a sun umbrella on the beach (75% versus 64%). PMID:22851947

Sancho-Garnier, Hélène; Pereira, Bruno; Césarini, Pierre

2012-01-01

222

Molecular evidence for color discrimination in the Atlantic sand fiddler crab, Uca pugilator  

PubMed Central

SUMMARY Fiddler crabs are intertidal brachyuran crabs that belong to the genus Uca. Approximately 97 different species have been identified, and several of these live sympatrically. Many have species-specific body color patterns that may act as signals for intra- and interspecific communication. To understand the behavioral and ecological role of this coloration we must know whether fiddler crabs have the physiological capacity to perceive color cues. Using a molecular approach, we identified the opsin-encoding genes and determined their expression patterns across the eye of the sand fiddler crab, Uca pugilator. We identified three different opsin-encoding genes (UpRh1, UpRh2 and UpRh3). UpRh1 and UpRh2 are highly related and have similarities in their amino acid sequences to other arthropod long- and medium-wavelength-sensitive opsins, whereas UpRh3 is similar to other arthropod UV-sensitive opsins. All three opsins are expressed in each ommatidium, in an opsin-specific pattern. UpRh3 is present only in the R8 photoreceptor cell, whereas UpRh1 and UpRh2 are present in the R1-7 cells, with UpRh1 expression restricted to five cells and UpRh2 expression present in three cells. Thus, one photoreceptor in every ommatidium expresses both UpRh1 and UpRh2, providing another example of sensory receptor coexpression. These results show that U. pugilator has the basic molecular machinery for color perception, perhaps even trichromatic vision. PMID:21113005

Rajkumar, Premraj; Rollmann, Stephanie M.; Cook, Tiffany A.; Layne, John E.

2010-01-01

223

Different types of pinealocytes as revealed by immunoelectron microscopy of anti-S-antigen and antiopsin binding sites in the pineal organ of toad, frog, hedgehog and bat.  

PubMed

S-antigen- and opsin-immunoreactive sites were studied in the pineal organ of toad (Bufo bufo), frog (Rana tigrina), hedgehog (Erinaceus roumanicus) and bat (Myotis myotis) by light microscopic avidin-biotin-peroxidase and electron microscopic immunoglobulin-gold (immunogold), protein A-gold and avidin-biotin-ferritin techniques. The corresponding retinas served as reference tissues. A large number of photoreceptors of toad and frog pineal organ exhibited either strong or weak S-antigen immunoreaction in the outer segments, perikarya and basal processes. A small number of photoreceptors was S-antigen-negative. In general, the intensity of the reaction was stronger in the immunoreactive outer segments of the pineal organ than in those of the rods and certain cones of the retina. In hedgehog and bat, the perikarya and processes of the pinealocytes were either strongly or weakly S-antigen-positive or they lacked immunogold labeling. By use of an antibovine rhodopsin antiserum either strong or weak opsin immunoreactivity was found in the pineal outer segments of toad and frog. A small number of pineal photoreceptors lacked opsin antigenic sites. Double labeling with both antibovine S-antigen and antibovine opsin antisera showed that the opsin immunoreaction was present in the outer segments which also exhibited S-antigen immunoreaction. In the pineal organ of hedgehog and bat, no opsin immunoreaction was observed with the antisera used. It is proposed that in the pineal organ at least two types of photoreceptors are present: one "rod-type" elaborating rhodopsin accompanied by S-antigen and one (or two) "cone-type(s)" using an unknown photopigment(s). Obviously, the different photoreceptors enable the animal to perceive the different wavelengths of the light spectrum. PMID:2937652

Vigh-Teichmann, I; Vigh, B; Gery, I; van Veen, T

1986-01-01

224

Spectral and temporal sensitivity of cone-mediated responses in mouse retinal ganglion cells  

PubMed Central

The retina uses two photoreceptor types to encode the wide range of light intensities in the natural environment. Rods mediate vision in dim light, whereas cones mediate vision in bright light. Mouse photoreceptors include only 3% cones, and the majority of these co-express two opsins (S, M), with peak sensitivity to either ultraviolet (360 nm) or green light (508 nm). The M:S opsin ratio varies across the retina but has not been characterized functionally, preventing quantitative study of cone-mediated vision. Furthermore, physiological and behavioral measurements suggested that mouse retina supports relatively slow temporal processing (peak sensitivity, ~2–5 Hz), compared to primates; however, past studies used visible wavelengths that are inefficient at stimulating mouse S opsin. Here, we measured the M:S opsin expression ratio across the mouse retina, as reflected by ganglion cell responses, in vitro, and probed cone-mediated ganglion cell temporal properties using ultraviolet light stimulation and linear systems analysis. From recordings in mice lacking rod function (Gnat1?/?, Rho?/?), we estimate ~70% M-opsin expression in far dorsal retina, dropping to <5% M-opsin expression throughout ventral retina. In mice lacking cone function (Gnat2cpfl3), light-adapted rod-mediated responses peaked at ~5–7 Hz. In wild-type mice, cone-mediated responses peaked at ~10 Hz, with substantial responsiveness up to ~30 Hz. Therefore, despite the small percentage of cones, cone-mediated responses in mouse ganglion cells are fast and robust, similar to those in primates. These measurements enable quantitative analysis of cone-mediated responses at all levels of the visual system. PMID:21613480

Wang, Yanbin V.; Weick, Michael; Demb, Jonathan B.

2011-01-01

225

Chemistry and biology of vision.  

PubMed

Visual perception in humans occurs through absorption of electromagnetic radiation from 400 to 780 nm by photoreceptors in the retina. A photon of visible light carries a sufficient amount of energy to cause, when absorbed, a cis,trans-geometric isomerization of the 11-cis-retinal chromophore, a vitamin A derivative bound to rhodopsin and cone opsins of retinal photoreceptors. The unique biochemistry of these complexes allows us to reliably and reproducibly collect continuous visual information about our environment. Moreover, other nonconventional retinal opsins such as the circadian rhythm regulator melanopsin also initiate light-activated signaling based on similar photochemistry. PMID:22074921

Palczewski, Krzysztof

2012-01-13

226

X chromosome: gene for color blindness, Matt RidleySite: DNA Interactive (www.dnai.org)  

NSDL National Science Digital Library

Interviewee: Matt Ridley DNAi Location:Genome>tour>genome spot>Color vision Location: chromosome X gene name: OPN1MW/OPN1LW (green opsin; red opsin) The two genes that produce red and green light-sensitive proteins are located on the X chromosome. Mutations in these genes can cause color blindness. Color blindness is a common inherited sex-linked disorder that affects a personÂ?s ability to see or recognize certain colors. Eight to ten percent of all males and one half of a percent of all females are color-blind.

2008-10-06

227

Phototransduction Motifs and Variations  

PubMed Central

Seeing begins in the photoreceptors, where light is absorbed and signaled to the nervous system. Throughout the animal kingdom, photoreceptors are diverse in design and purpose. Nonetheless, phototransduction—the mechanism by which absorbed photons are converted into an electrical response—is highly conserved and based almost exclusively on a single class of photoproteins, the opsins. In this Review, we survey the G protein-coupled signaling cascades downstream from opsins in photoreceptors across vertebrate and invertebrate species, noting their similarities as well as differences. PMID:19837030

Yau, King-Wai; Hardie, Roger C.

2010-01-01

228

Nilsson [6] has referred to eyes such as these as `burglar alarms'. None of  

E-print Network

those of chitons, is a `true' motion detector: that is, they do not compare sequential stimulation to the vertebrate opsins [7]. Chitons, which are only distant relatives of gastropods and bivalves, have no head­210. 2. Crozier, W.J., and Arey, L.B. (1918). On the significance of the reaction to shading in chiton

Maine, Eleanor

229

Vitamin B2-based Blue-Light Photoreceptors in the Retinohypothalamic Tract as the Photoactive Pigments for Setting the Circadian Clock in Mammals  

Microsoft Academic Search

In mammals the retina contains photoactive molecules responsible for both vision and circadian photoresponse systems. Opsins, which are located in rods and cones, are the pigments for vision but it is not known whether they play a role in circadian regulation. A subset of retinal ganglion cells with direct projections to the suprachiasmatic nucleus (SCN) are at the origin of

Yasuhide Miyamoto; Aziz Sancar

1998-01-01

230

Animal behaviour Evidence for distributed  

E-print Network

Animal behaviour Evidence for distributed light sensing in the skin of cuttlefish, Sepia report that the skin of cuttlefish, Sepia officinalis, contains opsin transcripts suggesting a possible. Cuttlefish, along with a number of other cephalopod species, have been shown to be colour-blind. Since

Hanlon, Roger T.

231

brief communications nature methods | VOL.11 NO.9 | SEPTEMBER2014 | 931  

E-print Network

energy of the b2-adrenergic receptor using ~109-fold less protein than conventional assays of concept, we focused on G protein­coupled receptors (GPCRs), which comprise the most common clinical drug receptor type 1 (CB1) and opsin. We used maleimide chemistry to fluorescently label single reactive

Cai, Long

232

This Provisional PDF corresponds to the article as it appeared upon acceptance. Fully formatted PDF and full text (HTML) versions will be made available soon.  

E-print Network

surrounding the opsin gene arrays of African cichlid fishes BMC Evolutionary Biology 2011, 11:120 doi:10 gene arrays of African cichlid fishes Kelly E O'Quin1 , Daniel Smith1,5 , Zan Naseer1,5 , Jane Schulte1 contribute to the adaptive evolution of gene expression, but functional alleles in these regions

Carleton, Karen L.

233

Mol. Biol. Evol. 18(8):15401550. 2001 2001 by the Society for Molecular Biology and Evolution. ISSN: 0737-4038  

E-print Network

. ISSN: 0737-4038 Cone Opsin Genes of African Cichlid Fishes: Tuning Spectral Sensitivity by Differential of molecular adaptation (Yokoyama and Yokoyama 1996; Golding and Dean 1998; Yokoyama 2000). Evidence for visual pigment adaptation by amino acid substitution includes the evolution of red and green color vision

Carleton, Karen L.

234

Defects in the MITF mi \\/ mi Apical Surface are Associated with a Failure of Outer Segment Elongation  

Microsoft Academic Search

The loss of MITF function in the MITFmi \\/ mimouse affects not only RPE differentiation, but also the development of rod photoreceptor outer segments. Our data indicate that opsin immunoreactivity is detected in the cell membrane and along the ONL\\/RPE border of developing MITFmi \\/ mirod photoreceptors and that rod outer segment morphogenesis is initiated. Although molecules associated with the

K. M. Bumsted; L. J. Rizzolo; C. J. Barnstable

2001-01-01

235

nature neurOSCIenCe VOLUME 15 | NUMBER 5 | MAY 2012 793 r e S Ou rC e  

E-print Network

electroporation (IUE). By delivering an adeno-associated virus (AAV) that expresses an opsin in a Cre interpretation. The brain targets of interest may be very small, very large or hard for the virus to access be infected by any serotype of virus or cannot be infected during brain development). A transgenic mouse

Han, Xue

236

Light Controls Growth and Development via a Conserved Pathway in the Fungal Kingdom  

Microsoft Academic Search

Light inhibits mating and haploid fruiting of the human fungal pathogen Cryptococcus neoformans, but the mechanisms involved were unknown. Two genes controlling light responses were discovered through candidate gene and insertional mutagenesis approaches. Deletion of candidate genes encoding a predicted opsin or phytochrome had no effect on mating, while strains mutated in the white collar 1 homolog gene BWC1 mated

Alexander Idnurm; Joseph Heitman

2005-01-01

237

Vision Research 40 (2000) 879890 Visual pigments of African cichlid fishes: evidence for ultraviolet  

E-print Network

Vision Research 40 (2000) 879­890 Visual pigments of African cichlid fishes: evidence cones revealed a visual pigment with peak sensitivity at 36894 nm. M. zebra also expresses a putative. © 2000 Elsevier Science Ltd. All rights reserved. Keywords: Opsin; Visual pigment; Ultraviolet vision

Carleton, Karen L.

238

Parallel amino acid replacements in the rhodopsins of the rockfishes (Sebastes spp.) associated with shifts in habitat depth  

E-print Network

Parallel amino acid replacements in the rhodopsins of the rockfishes (Sebastes spp.) associated is by amino acid replacement. In opsins, the seven transmembrane domains form a binding pocket, 1995; Sakmar, 2002; Yokoyama & Takenaka, 2004). Changes in the amino acid sequence within

Palumbi, Stephen

239

www.elsevier.com/locate/brainres Available online at www.sciencedirect.com  

E-print Network

in optogenetics and pharmacogenetics Gary Aston-Jonesa,n , Karl Deisserothb,c a Department of Neurosciences Keywords: Optogenetics Pharmacogenetics Channelrhodopsin DREADD Designer receptor Viral transduction s t r a c t Optogenetics with microbial opsin genes, and pharmacogenetics with designer receptors

Aston-Jones, Gary

240

48 Scientific American, November 2010 Photograph/Illustration by Artist Name November 2010, ScientificAmerican.com 49Photograph by Darren Braun  

E-print Network

moving animals--which electrodes and other traditional methods do not allow. Although optogenetics optogenetics, researchers can probe how the nervous system works in unprecedented detail. Their findings could development of microbial opsins and optogenetics. #12;50 Scientific American, November 2010 memories

Schnitzer, Mark

241

Optetrode: a multichannel readout for optogenetic control in freely moving mice  

Microsoft Academic Search

Recent advances in optogenetics have improved the precision with which defined circuit elements can be controlled optically in freely moving mammals; in particular, recombinase-dependent opsin viruses, used with a growing pool of transgenic mice expressing recombinases, allow manipulation of specific cell types. However, although optogenetic control has allowed neural circuits to be manipulated in increasingly powerful ways, combining optogenetic stimulation

Polina Anikeeva; Aaron S Andalman; Ilana Witten; Melissa Warden; Inbal Goshen; Logan Grosenick; Lisa A Gunaydin; Loren M Frank; Karl Deisseroth

2011-01-01

242

Photostimulator for optogenetic retinal prosthesis  

Microsoft Academic Search

The discovery that neurons can be photostimulated via genetic incorporation of artificial opsins offers potential for many new forms of neural prosthesis. In this work, we demonstrate a photostimulator which has both the irradiance requirement and the spatial resolution for retinal prosthesis. We characterise its electrical and optical properties and show its ability to accurately stimulate individual action potentials.

N. Grossman; K. Nikolic; V. Poher; B. McGovern; E. Drankasis; M. Neil; C. Toumazou; P. Degenaar

2009-01-01

243

Constitutively active rhodopsin mutants causing night blindness are effectively phosphorylated by GRKs but differ in arrestin-1 binding.  

PubMed

The effects of activating mutations associated with night blindness on the stoichiometry of rhodopsin interactions with G protein-coupled receptor kinase 1 (GRK1) and arrestin-1 have not been reported. Here we show that the monomeric form of WT rhodopsin and its constitutively active mutants M257Y, G90D, and T94I, reconstituted into HDL particles are effectively phosphorylated by GRK1, as well as two more ubiquitously expressed subtypes, GRK2 and GRK5. All versions of arrestin-1 tested (WT, pre-activated, and constitutively monomeric mutants) bind to monomeric rhodopsin and show the same selectivity for different functional forms of rhodopsin as in native disc membranes. Rhodopsin phosphorylation by GRK1 and GRK2 promotes arrestin-1 binding to a comparable extent, whereas similar phosphorylation by GRK5 is less effective, suggesting that not all phosphorylation sites on rhodopsin are equivalent in promoting arrestin-1 binding. The binding of WT arrestin-1 to phospho-opsin is comparable to the binding to its preferred target, P-Rh*, suggesting that in photoreceptors arrestin-1 only dissociates after opsin regeneration with 11-cis-retinal, which converts phospho-opsin into inactive phospho-rhodopsin that has lower affinity for arrestin-1. Reduced binding of arrestin-1 to the phospho-opsin form of G90D mutant likely contributes to night blindness caused by this mutation in humans. PMID:23872075

Vishnivetskiy, Sergey A; Ostermaier, Martin K; Singhal, Ankita; Panneels, Valerie; Homan, Kristoff T; Glukhova, Alisa; Sligar, Stephen G; Tesmer, John J G; Schertler, Gebhard F X; Standfuss, Joerg; Gurevich, Vsevolod V

2013-11-01

244

Regulation of photoreceptor gene expression by the retinal homeobox (Rx) gene product  

PubMed Central

The retinal homeobox (Rx) gene product is essential for eye development. However little is known about its molecular function. It has been demonstrated that Rx binds to photoreceptor conserved element (PCE-1), a highly conserved element found in the promoter region of photoreceptor-specific genes such as rhodopsin and red cone opsin. We verify that Rx is co-expressed with rhodopsin and red cone opsin in maturing photoreceptors and demonstrate that Rx binds to the rhodopsin and red cone opsin promoters in vivo. We also find that Rx can cooperate with the Xenopus analogs of Crx and Nrl, otx5b and XLMaf (respectively), to activate a Xenopus opsin promoter-dependent reporter. Finally, we demonstrate that reduction of Rx expression in tadpoles results in decreases in expression of several PCE-1 containing photoreceptor genes, abnormal photoreceptor morphology, and impaired vision. Our data suggests that Rx, in combination with other transcription factors, is necessary for normal photoreceptor gene expression, maintenance, and function. This establishes a direct role for Rx in regulation of genes expressed in a differentiated cell type. PMID:20060393

Pan, Yi; Martinez-De Luna, Reyna I.; Lou, Chih-Hong; Nekkalapudi, Srivamsi; Kelly, Lisa E.; Sater, Amy K.; El-Hodiri, Heithem M.

2010-01-01

245

Positive selection of a duplicated UV-sensitive visual pigment coincides with wing pigment evolution in Heliconius butterflies  

PubMed Central

The butterfly Heliconius erato can see from the UV to the red part of the light spectrum with color vision proven from 440 to 640 nm. Its eye is known to contain three visual pigments, rhodopsins, produced by an 11-cis-3-hydroxyretinal chromophore together with long wavelength (LWRh), blue (BRh) and UV (UVRh1) opsins. We now find that H. erato has a second UV opsin mRNA (UVRh2)—a previously undescribed duplication of this gene among Lepidoptera. To investigate its evolutionary origin, we screened eye cDNAs from 14 butterfly species in the subfamily Heliconiinae and found both copies only among Heliconius. Phylogeny-based tests of selection indicate positive selection of UVRh2 following duplication, and some of the positively selected sites correspond to vertebrate visual pigment spectral tuning residues. Epi-microspectrophotometry reveals two UV-absorbing rhodopsins in the H. erato eye with ?max = 355 nm and 398 nm. Along with the additional UV opsin, Heliconius have also evolved 3-hydroxy-DL-kynurenine (3-OHK)-based yellow wing pigments not found in close relatives. Visual models of how butterflies perceive wing color variation indicate this has resulted in an expansion of the number of distinguishable yellow colors on Heliconius wings. Functional diversification of the UV-sensitive visual pigments may help explain why the yellow wing pigments of Heliconius are so colorful in the UV range compared to the yellow pigments of close relatives lacking the UV opsin duplicate. PMID:20133601

Briscoe, Adriana D.; Bybee, Seth M.; Bernard, Gary D.; Yuan, Furong; Sison-Mangus, Marilou P.; Reed, Robert D.; Warren, Andrew D.; Llorente-Bousquets, Jorge; Chiao, Chuan-Chin

2010-01-01

246

Patterns in Teleost Photoreceptor Organization: A Characterization of Basal Body Positioning in Zebrafish Photoreceptors and Variations in Swordtail Photoreceptor Mosaics  

E-print Network

, many invertebrates, including Drosophila, have rhabdomeric photoreceptors. In rhabdomeric photoreceptors, rather than light sensitivity occurring in a modified primary cilium, it occurs in specialized microvilli (for review, see Rister and Desplan... in vertebrate and invertebrate photoreceptor development and phototransduction. Additionally, different photoreceptor types which express different opsins enable color vision for both vertebrates and invertebrates. However, in the Drosophila eye, a well...

Ramsey, Michelle

2014-04-17

247

Direct Innervation of GnRH Neurons by Encephalic Photoreceptors in Birds  

PubMed Central

In nonmammalian vertebrates, photic cues that regulate the timing of seasonal reproductive cyclicity are detected by nonretinal, nonpineal deep brain photoreceptors. It has long been assumed that the underlying mechanism involves the transmission of photic information from the photoreceptor to a circadian system, and thence to the reproductive axis. An alternative hypothesis is that there is direct communication between the brain photoreceptor and the reproductive axis. In the present study, light and confocal microscopy reveal that gonadotropin releasing hormone (GnRH) neurons and processes are scattered among photoreceptor cells (identified by their opsin-immunoreactivity) in the lateral septum (SL). In the median eminence (ME), opsin and GnRH immunoreactive fibers overlap extensively. Single and double label ultrastructural immunocytochemistry indicate that in the SL and preoptic area (POA), opsin positive terminals form axo-dendritic synapses onto GnRH dendrites. In the ME, opsin and GnRH terminals lie adjacent to each other, make contact with tanycytes, or terminate on the hypophyseal portal capillaries. These results reveal that brain photoreceptors communicate directly with GnRH-neurons; this represents a means by which photoperiodic information reaches the reproductive axis. PMID:11220777

Saldanha, Colin J.; Silverman, Ann-Judith; Silver, Rae

2012-01-01

248

Optobionic vision---a new genetically enhanced light on retinal prosthesis  

Microsoft Academic Search

The recent discovery that neurons can be photostimulated via genetic incorporation of artificial opsins is creating a revolution in the field of neural stimulation. In this paper we show its potential in the field of retinal prosthesis. We show that we need typically 100 mW cm-2 in instantaneous light intensity on the neuron in order to stimulate action potentials. We

Patrick Degenaar; Nir Grossman; Muhammad Ali Memon; Juan Burrone; Martin Dawson; Emmanuel Drakakis; Mark Neil; Konstantin Nikolic

2009-01-01

249

Mouse Cone Photoreceptors Co-express Two Functional Visual Arrestins  

PubMed Central

Arrestins are members of a superfamily of proteins that arrest the activity of G-protein coupled receptors. Mouse cone photoreceptors express two visual arrestins, Arr1 and Arr4 (Carr). We quantified their expression levels and subcellular distributions in mouse cones: total Arr1 was estimated to be in an ~ 6:1 ratio to cone opsin, about 50-fold higher than Arr4. Recordings from single cones of Arr1?/? and Arr4?/? mice establish that both proteins are competent to arrest the activity of photoactivated S- and M- cone opsins. Recordings from Arr1?/? , Arr4?/? double-knockout mice establish a requirement for at least one of the two visual arrestins for normal cone opsin inactivation at all flash intensities. These recordings also reveal low activity photoproducts of S- and M-opsins that are absent when Grk1 and an arrestin are co-expressed, but which decay 70-fold more rapidly than the comparable photoproducts of rhodopsin in rods. PMID:18701071

Nikonov, Sergei S.; Brown, Bruce M.; Davis, Jason A.; Zuniga, Freddi I.; Bragin, Alvina; Pugh, Edward N.; Craft, Cheryl M.

2008-01-01

250

INTRODUCTION Photoreceptor cells in the compound eye of the adult butterfly  

E-print Network

, the visual system among butterfly families is highly diverse and their color vision abilities have only begun361 INTRODUCTION Photoreceptor cells in the compound eye of the adult butterfly contain the visual pigment rhodopsin, which is composed of an opsin protein and a retinal-based chromophore. Most butterfly

251

Introduction Ever since Darwin's time (Darwin, 1874), there has been  

E-print Network

; Robertson and Monteiro, 2005). Nonetheless, discussions of the evolution of butterfly wing colors of information about sensory receptors. Previous studies of both butterfly wing color cues and color vision have in butterflies, the contribution of opsin evolution to sexual wing color dichromatism and interspecific

252

A butterfly eye's view of birds Francesca D. Frentiu1  

E-print Network

The striking color patterns of butterflies and birds have long interested biologists. But how these animals see. Color vision has evolved in butterflies through opsin gene duplications, through positive selection, Inc. Introduction Butterflies and birds possess some of the most-spectacular color displays among

253

An investigation of the B335 region through far infrared spectroscopy with ISO  

Microsoft Academic Search

We present far infrared spectra of the B335 dark cloud region, obtained with the Long Wavelength Spectrometer (LWS) on-board the ISO satellite. Deep spectra were obtained towards the far infrared outflow exciting source, located in the B335 core, and on the three associated Herbig Haro (HH) objects HH119 A, B and C. In addition, a region of about 9' in

B. Nisini; M. Benedettini; T. Giannini; P. E. Clegg; A. M. di Giorgio; S. J. Leeks; R. Liseau; D. Lorenzetti; S. Molinari; P. Saraceno; L. Spinoglio; E. Tommasi; G. J. White; H. A. Smith

1999-01-01

254

Mid to far-infrared spectroscopy of Sharpless 171  

Microsoft Academic Search

We have collected one-dimensional raster-scan observations of the active star-forming region Sharpless 171 (S171), a typical H Ii region-molecular cloud complex, with the three spectrometers (LWS, SWS, and PHT-S) on board ISO. We have detected 8 far-infrared fine-structure lines, [O Iii] 52 mu m, [N Iii] 57 mu m, [O I] 63 mu m, [O Iii] 88 mu m, [N

Y. Okada; T. Onaka; H. Shibai; Y. Doi

2003-01-01

255

The Living With a Star CDAW on the Solar and Geospace Connections of Solar Energetic Particles  

NASA Technical Reports Server (NTRS)

The Living With a Star Program is sponsoring its first CDAW (Coordinated Data Analysis Workshop) to be held July 23-26, 2002 at a conference support location near the NASA Goddard Space Flight Center. This CDAW's topic is Solar Energetic Particle events. The topic was chosen due to the breadth of the impact of SEP's on the space environment and terrestrial climate. General goals of the LWS CDAW are a) Stimulate LWS Science on the near term, b) Facilitate cross-disciplinary interaction between the LWS scientific and space environment communities, c) Produce science products for all potential users, and d) Assist in the development of the LWS data system. The workshop will proceed similar to a previous CDAW held in 1999 on Interplanetary Type 11 Shocks. A list of target events has been compiled, which can be found at the workshop home page. The page lists all of the SEP events from 1996 January to 2001 December with energy > 10 MeV particle intensities exceeding 10 PFU. Preparation for the workshop consists of identifying relevant data from a wide variety of sources (solar, interplanetary, magnetospheric and climatary), accumulating the data (frequently this consists of both raw data, processed data and plots to ease perusal during the workshop) and gathering the software tools. Participants in the workshop are expected to complete their contributions of data or models prior to arriving at the workshop. Most of the CDAW consists of joint analysis of this data; only a few introductory talks are given at the beginning of the workshop, with the rest of the time being devoted to producing scientific results. Additional symposia may be scheduled at a later date, which will allow a venue for scientific talks on the CDAW results and associated science. The poster will list the scientific goals of the workshop, as well as a scientific discussion of the data which has been accumulated thus far.

Thompson, Barbara J.; Gopalswamy, Nat; Colon, Gilberto (Technical Monitor)

2002-01-01

256

Wetland treatment of oil and gas well wastewaters. Quarterly technical report, November 25, 1993--March 24, 1994  

SciTech Connect

In the third quarterly report, adsorption of heavy metals ions such as Cu(II) and Cr(VI) onto soils drawn from the laboratory-type wetland (LW) was shown to be weak. On the other hand, it was shown that modified-clays did adsorb Cr(VI) ions strongly at pH 4.5. Further, studies on the pH dependence of the adsorption of {beta}-naphthoic acid, (NA), a well-documented contaminant in many oil and gas well waste waters (4), onto modified-clays were undertaken and it was shown that uptake of NA by modified-clays was of the high affinity type at pH 4.5 and 7.0, but weak at pH 9.0. Adsorption of heavy metal ions, Cu{sup 2+}, and CR(VI) onto algae, a proposed wetland amendment, was carried out and the results were presented and discussed in the fourth quarterly report. Studies on the dynamics of uptake of phenol and NA by laboratory-type wetlands (LWs) were initiated and preliminary results indicated that both phenol and NA were sorbed onto components of LWs. A mass balance model has been developed to quantify the fate of phenol in LWs. The model is based on the postulate that the fate of phenol in LWs can be attributed to a combination of (1) evaporation of solute and solvent, (2) adsorption of phenol onto various components of LW and (3) its biodegradation, both in solution and at solid-liquid interface. As an initial approximation, the latter two processes have been lumped together and incorporated into the model as an unit operation. Both zero order and first order kinetics for the disappearance of phenol have been considered. Evaporative losses of water and phenol have also been taken into account and this model is presented and discussed in this quarterly report.

Kadlec, R.H.; Srinivasan, K.R.

1994-04-15

257

Infrared and Millimetric Study of the Young Outflow Cepheus E  

Microsoft Academic Search

The Cepheus E outflow has been studied in the mid- and far-IR using the ISOCAM and Long Wavelength Spectrometer (LWS) instruments and at millimetric wavelengths using the Owens Valley Radio Observatory (OVRO). In the near- and mid-IR, its morphology is similar to that expected for a jet-driven outflow, where the leading bow shocks entrain and accelerate the surrounding molecular gas.

Amaya Moro-Martín; Alberto Noriega-Crespo; Sergio Molinari; Leonardo Testi; José Cernicharo; Anneila Sargent

2001-01-01

258

Learnability of Red-Green Opponency  

NASA Technical Reports Server (NTRS)

Lennie, Haake, and Williams found that in the lateral geniculate nucleus (LGN), parvocellular unit responses are consistent with the hypothesis that their input connectivity is blind to the difference between middle-wavelength-sensitive (MWS) and long-wavelength-sensitive (LWS) cones. Most of their cells have a total MWS input weight opposite in sign and similar in magnitude to their total LWS input weight. If these weights are exactly balanced, the construction of a red-green opponent system from such units is simple: such units need only be aligned so the signs of their outputs agree. Ahumada and Mulligan described an associative learning process which can accomplish this alignment. If the units are not balanced (carry some luminance information), the strong overlap between the MWS and LWS spectral responses can cause units to agree more on the basis of luminance, and the associative process fails to produce red-green opponency. The learning theory requires that the LGN units be nearly balanced (more strongly encode chromaticity than luminance) and quantitatively expresses the requirement: the principal component of the LGN outputs must be in the red-green rather than the luminance direction. We show that the cone weights of the monkey LGN cells measured by Derrington, Krauskopf, and Lennie can satisfy this learnability criterion even if the MWS spectral response is close to the LWS spectral response, simulating anomalous trichromacy. The learnability theory provides a source of visual system variation for explaining why different anomalous trichromats may make the same average anomaloscope match (same pigments), but have either narrow (good opponent learning) or wide (poor learning) ranges of acceptable matches.

Ahumada, Albert J., Jr.

1997-01-01

259

Solar Sentinels: Report of the Science and Technology Definition Team  

NASA Technical Reports Server (NTRS)

The goal of NASA s Living With a Star (LWS) program is to develop the scientific understanding necessary to effectively address those aspects of the connected Sun Earth system that directly affect life and society. Along with the other elements of LWS, Solar Sentinels aims to discover, understand, and model the heliospheric initiation, propagation, and solar connection of those energetic phenomena that adversely affect space exploration and life and society here on Earth. The Solar Sentinels mission will address the following questions: (1) How, where, and under what circumstances are solar energetic particles (SEPs) accelerated to high energies and how do they propagate through the heliosphere? And (2) How are solar wind structures associated with these SEPs, like CMEs, shocks, and high-speed streams, initiated, propagate, evolve, and interact in the inner heliosphere? The Sentinels STDT recommends implementing this mission in two portions, one optimized for inner heliospheric in-situ measurements and the other for solar remote observations. Sentinels will greatly enhance the overall LWS science return.

2006-01-01

260

Spatial variation of the longitudinal dispersion coefficient in an estuary  

NASA Astrophysics Data System (ADS)

The effective longitudinal dispersion is a primary tool for determining property distributions in estuaries. Most previous studies have examined the longitudinal dispersion coefficient for the average tidal condition. However, information on spatial and temporal variations of this coefficient at low and high tide is scarce. Three years of hydrographic data taken at low and high tide along the main axis of the Sumjin River Estuary (SRE), Korea are used to estimate the spatial and temporal variation of the effective longitudinal dispersion coefficient. The range of the dispersion coefficient is rather broad at high water slack (HWS) and narrower at low water slack (LWS) because of the different tidal amplitudes. The spatially varying dispersion coefficient has maximal values (>300 m2 s-1) near the mouth at high water and decreases gradually upstream, with fluctuations. The temporally varying dispersion coefficient appears to be positively correlated with river discharges at both low and high tide. The dispersion varies with the square root of river discharges at HWS and LWS. The dispersive salt fluxes increases with increasing river discharges and decreases with decreasing river discharges at HWS and LWS. Estimation of the numerical values of the effective longitudinal dispersion coefficient in the SRE can be useful for better understanding of the distributions of other tracers in the SRE as well as for developing and testing hypotheses about various mixing mechanisms.

Shaha, D. C.; Cho, Y.-K.; Kwak, M.-T.; Kundu, S. R.; Jung, K. T.

2011-08-01

261

Spatial variation of the longitudinal dispersion coefficient in an estuary  

NASA Astrophysics Data System (ADS)

The effective longitudinal dispersion is a primary tool for determining property distributions in estuaries. Most previous studies have examined the longitudinal dispersion coefficient for the average tidal condition. However, information on spatial and temporal variations of this coefficient at low and high tides is scarce. Three years of hydrographic data taken at low and high tide along the main axis of the Sumjin River Estuary (SRE), Korea are used to estimate the spatial and temporal variation of the effective longitudinal dispersion coefficient. The range of the dispersion coefficient is rather broad at high water slack (HWS) and narrower at low water slack (LWS) because of the different tidal amplitudes. The spatially varying dispersion coefficient has maximal values (>300 m2 s-1) near the mouth at high water and decreases gradually upstream, with fluctuations. The temporally varying dispersion coefficient appears to be positively correlated with river discharges at both low and high tide. The dispersion varies with the square root of river discharges at HWS and LWS. The dispersive salt fluxes increases with increasing river discharges and decreases with decreasing river discharges at HWS and LWS. Estimation of the numerical values of the effective longitudinal dispersion coefficient in the SRE can be useful for better understanding of the distributions of other tracers in the SRE as well as for developing and testing hypotheses about various mixing mechanisms.

Shaha, D. C.; Cho, Y.-K.; Kwak, M.-T.; Kundu, S. R.; Jung, K. T.

2011-12-01

262

Gene Therapy Rescues Cone Structure and Function in the 3-Month-Old rd12 Mouse: A Model for Midcourse RPE65 Leber Congenital Amaurosis  

PubMed Central

Purpose. RPE65 function is necessary in the retinal pigment epithelium (RPE) to generate chromophore for all opsins. Its absence results in vision loss and rapid cone degeneration. Recent Leber congenital amaurosis type 2 (LCA with RPE65 mutations) phase I clinical trials demonstrated restoration of vision on RPE65 gene transfer into RPE cells overlying cones. In the rd12 mouse, a naturally occurring model of RPE65-LCA early cone degeneration was observed; however, some peripheral M-cones remained. A prior study showed that AAV-mediated RPE65 expression can prevent early cone degeneration. The present study was conducted to test whether the remaining cones in older rd12 mice can be rescued. Methods. Subretinal treatment with the scAAV5-smCBA-hRPE65 vector was initiated at postnatal day (P)14 and P90. After 2 months, electroretinograms were recorded, and cone morphology was analyzed by using cone-specific peanut agglutinin and cone opsin–specific antibodies. Results. Cone degeneration started centrally and spread ventrally, with cells losing cone-opsin staining before that for the PNA-lectin–positive cone sheath. Gene therapy starting at P14 resulted in almost wild-type M- and S-cone function and morphology. Delaying gene-replacement rescued the remaining M-cones, and most important, more M-cone opsin–positive cells were identified than were present at the onset of gene therapy, suggesting that opsin expression could be reinitiated in cells with cone sheaths. Conclusions. The results support and extend those of the previous study that gene therapy can stop early cone degeneration, and, more important, they provide proof that delayed treatment can restore the function and morphology of the remaining cones. These results have important implications for the ongoing LCA2 clinical trials. PMID:21169527

Li, Xia; Li, Wensheng; Dai, Xufeng; Kong, Fansheng; Zheng, Qinxiang; Zhou, Xiangtian; Lü, Fan; Chang, Bo; Rohrer, Bärbel; Hauswirth, William. W.; Qu, Jia; Pang, Ji-jing

2011-01-01

263

Unique system of photoreceptors in sea urchin tube feet  

PubMed Central

Different sea urchin species show a vast variety of responses to variations in light intensity; however, despite this behavioral evidence for photosensitivity, light sensing in these animals has remained an enigma. Genome information of the recently sequenced purple sea urchin (Strongylocentrotus purpuratus) allowed us to address this question from a previously unexplored molecular perspective by localizing expression of the rhabdomeric opsin Sp-opsin4 and Sp-pax6, two genes essential for photoreceptor function and development, respectively. Using a specifically designed antibody against Sp-Opsin4 and in situ hybridization for both genes, we detected expression in two distinct groups of photoreceptor cells (PRCs) located in the animal's numerous tube feet. Specific reactivity of the Sp-Opsin4 antibody with sea star optic cushions, which regulate phototaxis, suggests a similar visual function in sea urchins. Ultrastructural characterization of the sea urchin PRCs revealed them to be of a microvillar receptor type. Our data suggest that echinoderms, in contrast to chordates, deploy a microvillar, r-opsin–expressing PRC type for vision, a feature that has been so far documented only in protostome animals. Surprisingly, sea urchin PRCs lack any associated screening pigment. Indeed, one of the tube foot PRC clusters may account for directional vision by being shaded through the opaque calcite skeleton. The PRC axons connect to the animal internal nervous system, suggesting an integrative function beyond local short circuits. Because juveniles display no phototaxis until skeleton completion, we suggest a model in which the entire sea urchin, deploying its skeleton as PRC screening device, functions as a huge compound eye. PMID:21536888

Ullrich-Lüter, Esther M; Dupont, Sam; Arboleda, Enrique; Hausen, Harald; Arnone, Maria Ina

2011-01-01

264

Alouatta Trichromatic Color Vision: Cone Spectra and Physiological Responses Studied with Microspectrophotometry and Single Unit Retinal Electrophysiology  

PubMed Central

The howler monkeys (Alouatta sp.) are the only New World primates to exhibit routine trichromacy. Both males and females have three cone photopigments. However, in contrast to Old World monkeys, Alouatta has a locus control region upstream of each opsin gene on the X-chromosome and this might influence the retinal organization underlying its color vision. Post-mortem microspectrophotometry (MSP) was performed on the retinae of two male Alouatta to obtain rod and cone spectral sensitivities. The MSP data were consistent with only a single opsin being expressed in each cone and electrophysiological data were consistent with this primate expressing full trichromacy. To study the physiological organization of the retina underlying Alouatta trichromacy, we recorded from retinal ganglion cells of the same animals used for MSP measurements with a variety of achromatic and chromatic stimulus protocols. We found MC cells and PC cells in the Alouatta retina with similar properties to those previously found in the retina of other trichromatic primates. MC cells showed strong phasic responses to luminance changes and little response to chromatic pulses. PC cells showed strong tonic response to chromatic changes and small tonic response to luminance changes. Responses to other stimulus protocols (flicker photometry; changing the relative phase of red and green modulated lights; temporal modulation transfer functions) were also similar to those recorded in other trichromatic primates. MC cells also showed a pronounced frequency double response to chromatic modulation, and with luminance modulation response saturation accompanied by a phase advance between 10–20 Hz, characteristic of a contrast gain mechanism. This indicates a very similar retinal organization to Old-World monkeys. Cone-specific opsin expression in the presence of a locus control region for each opsin may call into question the hypothesis that this region exclusively controls opsin expression. PMID:25405863

Silveira, Luiz Carlos L.; Saito, Cézar A.; da Silva Filho, Manoel; Kremers, Jan; Bowmaker, James K.; Lee, Barry B.

2014-01-01

265

Erx, a novel retina-specific homeodomain transcription factor, can interact with Ret 1/PCEI sites.  

PubMed

Our previous studies on the transcriptional regulation of rod opsin gene expression had defined a strikingly conserved element, Ret 1/PCEI, present in the upstream regulatory regions of opsin and other photoreceptor-specific genes. This element interacts with a 40 kDa, developmentally regulated, retina-specific protein. In this study we report the cloning of the novel retina-specific homeodomain protein Erx. Erx contains a homeodomain that is 79% homologous to that of Drosophila empty spiracles. This 40 kDa protein can interact with the Ret 1 element in electrophoretic mobility shift assays. Mutation of key residues in Ret 1 eliminates all Erx binding. Transient transfection of Y79 retinobalstoma cells with Erx leads to significant transcriptional activation of a reporter gene via Ret 1 elements. We conclude that Erx is the Ret 1 binding activity. This is the first example of a Q50 homeodomain protein expressed in retinal photoreceptors. PMID:9735352

Martinez, J A; Barnstable, C J

1998-09-01

266

Cone pigment variations in four genera of new world monkeys.  

PubMed

Previous research revealed significant individual variations in opsin genes and cone photopigments in several species of platyrrhine (New World) monkeys and showed that these in turn can yield significant variations in color vision. To extend the understanding of the nature of color vision in New World monkeys, electroretinogram flicker photometry was used to obtain spectral sensitivity measurements from representatives of four platyrrhine genera (Cebus, Leontopithecus, Saguinus, Pithecia). Animals from each genus were found to be polymorphic for middle to long-wavelength (M/L) sensitive cones. The presence of a short-wavelength sensitive photopigment was established as well so these animals conform to the earlier pattern in predicting that all male monkeys are dichromats while, depending on their opsin gene array, individual females can be either dichromatic or trichromatic. Across subjects a total of five different M/L cone pigments were inferred with a subset of three of these present in each species. PMID:12535982

Jacobs, Gerald H; Deegan, Jess F

2003-02-01

267

A comprehensive multiscale framework for simulating optogenetics in the heart  

PubMed Central

Optogenetics has emerged as an alternative method for electrical control of the heart, where illumination is used to elicit a bioelectric response in tissue modified to express photosensitive proteins (opsins). This technology promises to enable evocation of spatiotemporally precise responses in targeted cells or tissues, thus creating new possibilities for safe and effective therapeutic approaches to ameliorate cardiac function. Here, we present a comprehensive framework for multi-scale modelling of cardiac optogenetics, allowing both mechanistic examination of optical control and exploration of potential therapeutic applications. The framework incorporates accurate representations of opsin channel kinetics and delivery modes, spatial distribution of photosensitive cells, and tissue illumination constraints, making possible the prediction of emergent behaviour resulting from interactions at sub-organ scales. We apply this framework to explore how optogenetic delivery characteristics determine energy requirements for optical stimulation and to identify cardiac structures that are potential pacemaking targets with low optical excitation threshold. PMID:23982300

Boyle, Patrick M; Williams, John C; Ambrosi, Christina M; Entcheva, Emilia; Trayanova, Natalia A

2013-01-01

268

The Giant Mottled Eel, Anguilla marmorata, Uses Blue-Shifted Rod Photoreceptors during Upstream Migration  

PubMed Central

Catadromous fishes migrate between ocean and freshwater during particular phases of their life cycle. The dramatic environmental changes shape their physiological features, e.g. visual sensitivity, olfactory ability, and salinity tolerance. Anguilla marmorata, a catadromous eel, migrates upstream on dark nights, following the lunar cycle. Such behavior may be correlated with ontogenetic changes in sensory systems. Therefore, this study was designed to identify changes in spectral sensitivity and opsin gene expression of A. marmorata during upstream migration. Microspectrophotometry analysis revealed that the tropical eel possesses a duplex retina with rod and cone photoreceptors. The ?max of rod cells are 493, 489, and 489 nm in glass, yellow, and wild eels, while those of cone cells are 508, and 517 nm in yellow, and wild eels, respectively. Unlike European and American eels, Asian eels exhibited a blue-shifted pattern of rod photoreceptors during upstream migration. Quantitative gene expression analyses of four cloned opsin genes (Rh1f, Rh1d, Rh2, and SWS2) revealed that Rh1f expression is dominant at all three stages, while Rh1d is expressed only in older yellow eel. Furthermore, sequence comparison and protein modeling studies implied that a blue shift in Rh1d opsin may be induced by two known (N83, S292) and four putative (S124, V189, V286, I290) tuning sites adjacent to the retinal binding sites. Finally, expression of blue-shifted Rh1d opsin resulted in a spectral shift in rod photoreceptors. Our observations indicate that the giant mottled eel is color-blind, and its blue-shifted scotopic vision may influence its upstream migration behavior and habitat choice. PMID:25101636

Wang, Feng-Yu; Fu, Wen-Chun; Wang, I-Li

2014-01-01

269

Analysis of Kinesin2 Function in Photoreceptor Cells Using Synchronous Cre-loxP Knockout of Kif3a with RHO-Cre  

Microsoft Academic Search

PURPOSE. To determine the relationship between the presence of kinesin-2 and photoreceptor cell viability and opsin trans- port, by generating RHO-Cre transgenic mice and breeding them to mice with a floxed kinesin-2 motor gene. METHODS. Different lines of RHO-Cre transgenic mice were generated and characterized by transgene expression, histol- ogy, and electrophysiology. Mice from one line, showing uni- form transgene

David Jimeno; Leonard Feiner; Concepcion Lillo; Karen Teofilo; Lawrence S. B. Goldstein; Eric A. Pierce; David S. Williams

2006-01-01

270

[Inherited colour vision deficiencies--from Dalton to molecular genetics].  

PubMed

In recent years, great advances have been made in our understanding of the molecular basis of colour vision defects, as well as of the patterns of genetic variation in individuals with normal colour vision. Molecular genetic analyses have explained the diversity of types and degrees of severity in colour vision anomalies, their frequencies, pronounced individual variations in test results, etc. New techniques have even enabled the determination of John Dalton's real colour vision defect, 150 years after his death. Inherited colour vision deficiencies most often result from the mutations of genes that encode cone opsins. Cone opsin genes are linked to chromosomes 7 (the S or "blue" gene) and X (the L or "red" gene and the M or "green" gene). The L and M genes are located on the q arm of the X chromosome in a head-to-tail array, composed of 2 to 6 (typically 3) genes--a single L is followed by one or more M genes. Only the first two genes of the array are expressed and contribute to the colour vision phenotype. The high degree of homology (96%) between the L and M genes predisposes them to unequal recombination, leading to gene deletion or the formation of hybrid genes (comprising portions of both the L and M genes), explaining the majority of the common red-green colour vision deficiencies. The severity of any deficiency is influenced by the difference in spectral sensitivity between the opsins encoded by the first two genes of the array. A rare defect, S monochromacy, is caused either by the deletion of the regulatory region of the array or by mutations that inactivate the L and M genes. Most recent research concerns the molecular basis of complete achromatopsia, a rare disorder that involves the complete loss of all cone function. This is not caused by mutations in opsin genes, but in other genes that encode cone-specific proteins, e.g. channel proteins and transducin. PMID:16758855

Cvetkovi?, Dragana; Cvetkovi?, Dobrosav

2005-01-01

271

Common Transcriptional Mechanisms for Visual Photoreceptor Cell Differentiation among Pancrustaceans  

PubMed Central

A hallmark of visual rhabdomeric photoreceptors is the expression of a rhabdomeric opsin and uniquely associated phototransduction molecules, which are incorporated into a specialized expanded apical membrane, the rhabdomere. Given the extensive utilization of rhabdomeric photoreceptors in the eyes of protostomes, here we address whether a common transcriptional mechanism exists for the differentiation of rhabdomeric photoreceptors. In Drosophila, the transcription factors Pph13 and Orthodenticle (Otd) direct both aspects of differentiation: rhabdomeric opsin transcription and rhabdomere morphogenesis. We demonstrate that the orthologs of both proteins are expressed in the visual systems of the distantly related arthropod species Tribolium castaneum and Daphnia magna and that their functional roles are similar in these species. In particular, we establish that the Pph13 homologs have the ability to bind a subset of Rhodopsin core sequence I sites and that these sites are present in key phototransduction genes of both Tribolium and Daphnia. Furthermore, Pph13 and Otd orthologs are capable of executing deeply conserved functions of photoreceptor differentiation as evidenced by the ability to rescue their respective Drosophila mutant phenotypes. Pph13 homologs are equivalent in their ability to direct both rhabdomere morphogenesis and opsin expression within Drosophila, whereas Otd paralogs demonstrate differential abilities to regulate photoreceptor differentiation. Finally, loss-of-function analyses in Tribolium confirm the conserved requirement of Pph13 and Otd in regulating both rhabdomeric opsin transcription and rhabdomere morphogenesis. Taken together, our data identify components of a regulatory framework for rhabdomeric photoreceptor differentiation in Pancrustaceans, providing a foundation for defining ancestral regulatory modules of rhabdomeric photoreceptor differentiation. PMID:24991928

Mahato, Simpla; Morita, Shinichi; Tucker, Abraham E.; Liang, Xulong; Jackowska, Magdalena; Friedrich, Markus; Shiga, Yasuhiro; Zelhof, Andrew C.

2014-01-01

272

Spatial and Temporal Expression of AP1 Responsive Rod Photo receptor Genes and bZIP Transcription Factors During Develop ment of the Rat Retina  

Microsoft Academic Search

Purpose: The promoter region of the rod-specific ? subunit of cGMP PDE (?-PDE) and opsin genes contains highly conserved cis-acting elements, which include an AP-1 and\\/or Nrl response element (NRE: An extended AP-1 like se- quence). Transactivation of AP-1 or NRE appears necessary to drive expression of these rod-specific genes during adult- hood, however, their role during development is relatively

Lihua He; Martin L. Campbell; Devesh Srivastava; Yvonne S. Blocker; J. Robin Harris; Anand Swaroop; Donald A. Fox

1998-01-01

273

Ultraviolet photopigment sensitivity and ocular media transmittance in gulls, with an evolutionary perspective.  

PubMed

Gulls (Laridae excluding Sternidae) appear to be the only shorebirds (Charadriiformes) that have a short wavelength sensitive type 1 (SWS1) cone pigment opsin tuned to ultraviolet (UV) instead of violet. However, the apparent UV-sensitivity has only been inferred indirectly, via the interpretation that the presence of cysteine at the key amino acid position 90 in the SWS1 opsin confers UV sensitivity. Unless the cornea and the lens efficiently transmit UV to the retina, gulls might in effect be similar to violet-sensitive birds in spectral sensitivity even if they have an ultraviolet sensitive (UVS) SWS1 visual pigment. We report that the spectral transmission of the cornea and lens of great black-backed Larus marinus and herring gulls L. argentatus allow UV-sensitivity, having a lambda(T0.5) value, 344 nm, similar to the ocular media of UV sensitive birds. By molecular sequencing of the second alpha-helical transmembrane region of the SWS1 opsin gene we could also infer that 15 herring gulls and 16 yellow-legged gulls L. michahellis, all base-pair identical, are genetically UV-sensitive. PMID:19308422

Håstad, Olle; Partridge, Julian C; Odeen, Anders

2009-06-01

274

Structure and function in rhodopsin: the role of asparagine-linked glycosylation.  

PubMed Central

Rhodopsin, the dim light photoreceptor of the rod cell, is an integral membrane protein that is glycosylated at Asn-2 and Asn-15. Here we report experiments on the role of the glycosylation in rhodopsin folding and function. Nonglycosylated opsin was prepared by expression of a wild-type bovine opsin gene in COS-1 cells in the presence of tunicamycin, an inhibitor of asparagine-linked glycosylation. The non-glycosylated opsin folded correctly as shown by its normal palmitoylation, transport to the cell surface, and the formation of the characteristic rhodopsin chromophore (lambda max, 500 nm) with 11-cis-retinal. However, the nonglycosylated rhodopsin showed strikingly low light-dependent activation of GT at concentration levels comparable with those of glycosylated rhodopsin. Amino acid replacements at positions 2 and 15 and the cognate tripeptide consensus sequence [Asn-2-->Gln, Gly-3-->Cys(Pro), Thr-4-->Lys, Asn-15-->Ala(Cys, Glu, Lys, Gln, Arg), Lys-16-->Cys(Arg), Thr-17-->Met(Val)] showed that the substitutions at Asn-2, Gly-3, and Thr-4 had no significant effect on the folding, cellular transport, and/or function of rhodopsin, whereas those at Asn-15 and Lys-16 caused poor folding and were defective in transport to the cell surface. Further, mutant pigments with amino acid replacements at Asn-15 and Thr-17 activated GT very poorly. We conclude that Asn-15 glycosylation is important in signal transduction. Images PMID:8171029

Kaushal, S; Ridge, K D; Khorana, H G

1994-01-01

275

Diversity of Color Vision: Not All Australian Marsupials Are Trichromatic  

PubMed Central

Color vision in marsupials has recently emerged as a particularly interesting case among mammals. It appears that there are both dichromats and trichromats among closely related species. In contrast to primates, marsupials seem to have evolved a different type of trichromacy that is not linked to the X-chromosome. Based on microspectrophotometry and retinal whole-mount immunohistochemistry, four trichromatic marsupial species have been described: quokka, quenda, honey possum, and fat-tailed dunnart. It has, however, been impossible to identify the photopigment of the third cone type, and genetically, all evidence so far suggests that all marsupials are dichromatic. The tammar wallaby is the only Australian marsupial to date for which there is no evidence of a third cone type. To clarify whether the wallaby is indeed a dichromat or trichromatic like other Australian marsupials, we analyzed the number of cone types in the “dichromatic” wallaby and the “trichromatic” dunnart. Employing identical immunohistochemical protocols, we confirmed that the wallaby has only two cone types, whereas 20–25% of cones remained unlabeled by S- and LM-opsin antibodies in the dunnart retina. In addition, we found no evidence to support the hypothesis that the rod photopigment (rod opsin) is expressed in cones which would have explained the absence of a third cone opsin gene. Our study is the first comprehensive and quantitative account of color vision in Australian marsupials where we now know that an unexpected diversity of different color vision systems appears to have evolved. PMID:21151905

Ebeling, Wiebke; Natoli, Riccardo C.; Hemmi, Jan M.

2010-01-01

276

Squid retinochrome  

PubMed Central

Retinochrome is a photosensitive pigment located primarily in the inner portions of the visual cells of cephalopods. Its absorption spectrum resembles that of rhodopsin, but its chromophore is all-trans retinal, which light isomerizes to 11-cis, the reverse of the situation in rhodopsin. The 11-cis photoproduct of retinochrome slowly reverts to retinochrome in the dark. The chromophoric site of retinochrome is more reactive than that of most visual pigments: (a) Hydroxylamine converts retinochrome in the dark to all-trans retinal oxime + retinochrome opsin. (by Sodium borohydride reduces it to N-retinyl opsin. (c) Lambda max of retinochrome shifts from 500 to 515 nm as the pH is raised from 6 to 10, with a loss of absorption above pH 8; meanwhile above this PH a second band appears at shorter wavelengths with lambda max 375 nm. These changes are reversible. (d) If retinochrome is incubated with all- trans 3-dehydroretinal (retinal2) in the dark, some 3- dehydroretinochrome (retinochrome2, lambda max about 515 nm) is formed. Conversely, when retinochrome2, made by adding all-trans retinal2 to bleached retinochrome or retinochrome opsin, is incubated in the dark with all-trans retinal some of it is converted to retinochrome. Retinal and 3-dehydroretinal therefore can replace each other as chromophores in the dark. PMID:235007

1975-01-01

277

Virally mediated optogenetic excitation and inhibition of pain in freely moving non-transgenic mice  

PubMed Central

Primary nociceptors are the first neurons involved in the complex processing system that regulates normal and pathological pain1. Our ability to excite and inhibit these neurons has been limited by pharmacological and electrical stimulation constraints; non-invasive excitation and inhibition of these neurons in freely moving non-transgenic animals has not been possible. Here we use an optogenetic2 strategy to bidirectionally control nociceptors of non-transgenic mice. Intra-sciatic nerve injection of adeno-associated viruses encoding an excitatory opsin enabled light-inducible stimulation of acute pain, place aversion, and optogenetically mediated reductions in withdrawal thresholds to mechanical and thermal stimuli. In contrast, viral delivery of an inhibitory opsin enabled light-inducible inhibition of acute pain perception, and reversed mechanical allodynia and thermal hyperalgesia in a model of neuropathic pain. Light was delivered transdermally enabling these behaviors to be induced in freely moving animals. This approach may have utility in basic and translational pain research, and enable rapid drug screening and testing of newly engineered opsins. PMID:24531797

Iyer, Shrivats Mohan; Montgomery, Kate L.; Towne, Chris; Lee, Soo Yeun; Ramakrishnan, Charu; Deisseroth, Karl; Delp, Scott L.

2014-01-01

278

Melanopsin mediates light-dependent relaxation in blood vessels.  

PubMed

Melanopsin (opsin4; Opn4), a non-image-forming opsin, has been linked to a number of behavioral responses to light, including circadian photo-entrainment, light suppression of activity in nocturnal animals, and alertness in diurnal animals. We report a physiological role for Opn4 in regulating blood vessel function, particularly in the context of photorelaxation. Using PCR, we demonstrate that Opn4 (a classic G protein-coupled receptor) is expressed in blood vessels. Force-tension myography demonstrates that vessels from Opn4(-/-) mice fail to display photorelaxation, which is also inhibited by an Opn4-specific small-molecule inhibitor. The vasorelaxation is wavelength-specific, with a maximal response at ?430-460 nm. Photorelaxation does not involve endothelial-, nitric oxide-, carbon monoxide-, or cytochrome p450-derived vasoactive prostanoid signaling but is associated with vascular hyperpolarization, as shown by intracellular membrane potential measurements. Signaling is both soluble guanylyl cyclase- and phosphodiesterase 6-dependent but protein kinase G-independent. ?-Adrenergic receptor kinase 1 (?ARK 1 or GRK2) mediates desensitization of photorelaxation, which is greatly reduced by GRK2 inhibitors. Blue light (455 nM) regulates tail artery vasoreactivity ex vivo and tail blood blood flow in vivo, supporting a potential physiological role for this signaling system. This endogenous opsin-mediated, light-activated molecular switch for vasorelaxation might be harnessed for therapy in diseases in which altered vasoreactivity is a significant pathophysiologic contributor. PMID:25404319

Sikka, Gautam; Hussmann, G Patrick; Pandey, Deepesh; Cao, Suyi; Hori, Daijiro; Park, Jong Taek; Steppan, Jochen; Kim, Jae Hyung; Barodka, Viachaslau; Myers, Allen C; Santhanam, Lakshmi; Nyhan, Daniel; Halushka, Marc K; Koehler, Raymond C; Snyder, Solomon H; Shimoda, Larissa A; Berkowitz, Dan E

2014-12-16

279

Identification and characterization of visual pigments in caecilians (Amphibia: Gymnophiona), an order of limbless vertebrates with rudimentary eyes.  

PubMed

In comparison with the other amphibian orders, the Anura (frogs) and Urodela (salamanders), knowledge of the visual system of the snake-like Gymnophiona (caecilians) is relatively sparse. Most caecilians are fossorial with, as far as is known any surface activity occurring mainly at night. They have relatively small, poorly developed eyes and might be expected to possess detectable changes in the spectral sensitivity of their visual pigments. Microspectrophotometry was used to determine the spectral sensitivities of the photoreceptors in three species of caecilian, Rhinatrema bivittatum, Geotrypetes seraphini and Typhlonectes natans. Only rod opsin visual pigment, which may be associated with scotopic (dim light) vision when accompanied by other 'rod-specific' components of the phototransduction cascade, was found to be present. Opsin sequences were obtained from the eyes of two species of caecilian, Ichthyophis cf. kohtaoensis and T. natans. These rod opsins were regenerated in vitro with 11-cis retinal to give pigments with spectral sensitivity peaks close to 500 nm. No evidence for cone photoreception, associated with diurnal and colour vision, was detected using molecular and physiological methods. Additionally, visual pigments are short-wavelength shifted in terms of the maximum absorption of light when compared with other amphibian lineages. PMID:20889838

Mohun, S M; Davies, W L; Bowmaker, J K; Pisani, D; Himstedt, W; Gower, D J; Hunt, D M; Wilkinson, M

2010-10-15

280

Tracking the primary photoconversion events in rhodopsins by ultrafast optical spectroscopy.  

PubMed

Opsins are a broad class of photoactive proteins, found in all classes of living beings from bacteria to higher animals, which work either as light-driven ion pumps or as visual pigments. The photoactive function in opsins is triggered by the ultrafast isomerization of the retinal chromophore around a specific carbon double bond, leading to a highly distorted, spectrally red-shifted photoproduct. Understanding, by either experimental or computational methods, the time course of this photoisomerization process is of utmost importance, both for its biological significance and because opsin proteins are the blueprint for molecular photoswitches. This paper focuses on the ultrafast 11-cis to all-trans isomerization in visual rhodopsins, and has a twofold goal: (i) to review the most recent experimental and computational efforts aimed at exposing the very early phases of photoconversion; and (ii) discuss future advanced experiments and calculations that will allow an even deeper understanding of the process. We present high time resolution pump-probe data, enabling us to follow the wavepacket motion through the conical intersection connecting excited and ground states, as well as femtosecond stimulated Raman scattering data allowing us to track the subsequent structural evolution until the first stable all-trans photoproduct is reached. We conclude by introducing computational results for two-dimensional electronic spectroscopy, which has the potential to provide even greater detail on the evolution of the electronic structure of retinal during the photoisomerization process. PMID:25429920

Polli, D; Rivalta, I; Nenov, A; Weingart, O; Garavelli, M; Cerullo, G

2015-02-01

281

Transcriptome profiling of developing photoreceptor subtypes reveals candidate genes involved in avian photoreceptor diversification.  

PubMed

Avian photoreceptors are a diverse class of neurons, comprised of four single cones, the two members of the double cone, and rods. The signaling events and transcriptional regulators driving the differentiation of these diverse photoreceptors are largely unknown. In addition, many distinctive features of photoreceptor subtypes, including spectral tuning, oil droplet size and pigmentation, synaptic targets, and spatial patterning, have been well characterized, but the molecular mechanisms underlying these attributes have not been explored. To identify genes specifically expressed in distinct chicken (Gallus gallus) photoreceptor subtypes, we developed fluorescent reporters that label photoreceptor subpopulations, isolated these subpopulations by using fluorescence-activated cell sorting, and subjected them to next-generation sequencing. By comparing the expression profiles of photoreceptors labeled with rhodopsin, red opsin, green opsin, and violet opsin reporters, we have identified hundreds of differentially expressed genes that may underlie the distinctive features of these photoreceptor subtypes. These genes are involved in a variety of processes, including phototransduction, transcriptional regulation, cell adhesion, maintenance of intra- and extracellular structure, and metabolism. Of particular note are a variety of differentially expressed transcription factors, which may drive and maintain photoreceptor diversity, and cell adhesion molecules, which may mediate spatial patterning of photoreceptors and act to establish retinal circuitry. These analyses provide a framework for future studies that will dissect the role of these various factors in the differentiation of avian photoreceptor subtypes. J. Comp. Neurol. 523:649-668, 2015. © 2014 Wiley Periodicals, Inc. PMID:25349106

Enright, Jennifer M; Lawrence, Karen A; Hadzic, Tarik; Corbo, Joseph C

2015-03-01

282

Signatures of Selection and Gene Conversion Associated with Human Color Vision Variation  

PubMed Central

Trichromatic color vision in humans results from the combination of red, green, and blue photopigment opsins. Although color vision genes have been the targets of active molecular and psychophysical research on color vision abnormalities, little is known about patterns of normal genetic variation in these genes among global human populations. The current study presents nucleotide sequence analyses and tests of neutrality for a 5.5-kb region of the X-linked long-wave “red” opsin gene (OPN1LW) in 236 individuals from ethnically diverse human populations. Our analysis of the recombination landscape across OPN1LW reveals an unusual haplotype structure associated with amino acid replacement variation in exon 3 that is consistent with gene conversion. Compared with the absence of OPN1LW amino acid replacement fixation since divergence from chimpanzee, the human population exhibits a significant excess of high-frequency OPN1LW replacements. Our results suggest that subtle changes in L-cone opsin wavelength absorption may have been adaptive during human evolution. PMID:15252758

Verrelli, Brian C.; Tishkoff, Sarah A.

2004-01-01

283

Signatures of selection and gene conversion associated with human color vision variation.  

PubMed

Trichromatic color vision in humans results from the combination of red, green, and blue photopigment opsins. Although color vision genes have been the targets of active molecular and psychophysical research on color vision abnormalities, little is known about patterns of normal genetic variation in these genes among global human populations. The current study presents nucleotide sequence analyses and tests of neutrality for a 5.5-kb region of the X-linked long-wave "red" opsin gene (OPN1LW) in 236 individuals from ethnically diverse human populations. Our analysis of the recombination landscape across OPN1LW reveals an unusual haplotype structure associated with amino acid replacement variation in exon 3 that is consistent with gene conversion. Compared with the absence of OPN1LW amino acid replacement fixation since divergence from chimpanzee, the human population exhibits a significant excess of high-frequency OPN1LW replacements. Our results suggest that subtle changes in L-cone opsin wavelength absorption may have been adaptive during human evolution. PMID:15252758

Verrelli, Brian C; Tishkoff, Sarah A

2004-09-01

284

Self-organized criticality and color vision: A guide to water-protein landscape evolution  

NASA Astrophysics Data System (ADS)

We focus here on the scaling properties of small interspecies differences between red cone opsin transmembrane proteins, using a hydropathic elastic roughening tool previously applied to the rhodopsin rod transmembrane proteins. This tool is based on a non-Euclidean hydropathic metric realistically rooted in the atomic coordinates of 5526 protein segments, which thereby encapsulates universal non-Euclidean long-range differential geometrical features of water films enveloping globular proteins in the Protein Data Bank. Whereas the rhodopsin blue rod water films are smoothest in humans, the red cone opsins’ water films are optimized for smoothness in cats and elephants, consistent with protein species landscapes that evolve differently in different contexts. We also analyze red cone opsins in the chromatophore-containing family of chameleons, snakes, zebrafish and goldfish, where short- and long-range (BLAST and hydropathic) amino acid (aa) correlations are found with values as large as 97%-99%. We use hydropathic aa optimization to estimate the maximum number Nmax of color shades that the human eye can discriminate, and obtain 106

Phillips, J. C.

2013-02-01

285

Non-invasive activation of optogenetic actuators  

NASA Astrophysics Data System (ADS)

The manipulation of genetically targeted neurons with light (optogenetics) continues to provide unprecedented avenues into studying the function of the mammalian brain. However, potential translation into the clinical arena faces a number of significant hurdles, foremost among them the need for insertion of optical fibers into the brain to deliver light to opsins expressed on neuronal membranes. In order to overcome these hardware-related problems, we have developed an alternative strategy for delivering light to opsins which does not involve fiber implants. Rather, the light is produced by a protein, luciferase, which oxidizes intravenously applied substrate, thereby emitting bioluminescence. In proof-ofprinciple studies employing a fusion protein of a light-generating luciferase to a light-sensing opsin (luminopsin), we showed that light emitted by Gaussia luciferase is indeed able to activate channelrhodopsin, allowing modulation of neuronal activity when expressed in cultured neurons. Here we assessed applicability of the concept in vivo in mice expressing luminopsins from viral vectors and from genetically engineered transgenes. The experiments demonstrate that intravenously applied substrate reaches neurons in the brain, causing the luciferase to produce bioluminescence which can be imaged in vivo, and that activation of channelrhodopsin by bioluminescence is sufficient to affect behavior. Further developments of such technology based on combining optogenetics with bioluminescence - i.e. combining lightsensing molecules with biologically produced light through luciferases - should bring optogenetics closer to clinical applications.

Birkner, Elisabeth; Berglund, Ken; Klein, Marguerita E.; Augustine, George J.; Hochgeschwender, Ute

2014-03-01

286

The influence of chromatic background on the photosensitivity of tilapia erythrophores  

PubMed Central

Summary Non-mammalian vertebrates and invertebrates use extraretinal photoreceptors to detect light and perform diverse non-image-forming functions. Compared to well-studied visual systems, the effect of ambient light conditions on photosensory systems of extraretinal photoreceptors is poorly understood. Chromatophores are photosensitive dermal pigment cells that play an important role in the formation of body color patterns to fit the surrounding environment. Here, we used tilapia erythrophores to investigate the relationship between environmental light and chromatophore photoresponses. All erythrophores from three spectral conditions aggregated their pigment granules in UV/short wavelengths and dispersed in middle/long wavelengths. Unlike retinal visual systems, environmental light did not change the usage of the primary opsins responsible for aggregation and dispersion. In addition, short wavelength-rich and red-shifted background conditions led to an inhibitory effect on erythrophore photoresponses. We suggest that, as extraretinal photoreceptors for non-image-forming functions, chromatophores directly adjust their photoresponse sensitivity via changes in opsin expression levels rather than opsin types when environmental light changes. PMID:24414206

Chen, Shyh-Chi; Hornsby, Mark A. W.; Robertson, R. Meldrum; Hawryshyn, Craig W.

2014-01-01

287

In vivo assembly of rhodopsin from expressed polypeptide fragments.  

PubMed Central

Rhodopsin folding and assembly were investigated by expression of five bovine opsin gene fragments separated at points corresponding to proteolytic cleavage sites in the second or third cytoplasmic regions. The CH(1-146) and CH(147-348) gene fragments encode amino acids 1-146 and 147-348 of opsin, while the TH(1-240) and TH(241-348) gene fragments encode amino acids 1-240 and 241-348, respectively. Another gene fragment, CT(147-240), encodes amino acids 147-240. All five opsin polypeptide fragments were stably produced upon expression of the corresponding gene fragments in COS-1 cells. The singly expressed polypeptide fragments failed to form a chromophore with 11-cis-retinal, whereas coexpression of two or three complementary fragments [CH(1-146) + CH(147-348), TH(1-240) + TH(241-348), or CH(1-146) + CT(147-240) + TH(241-348)] formed pigments with spectral properties similar to wild-type rhodopsin. The NH2-terminal polypeptide in these rhodopsins showed a glycosylation pattern characteristic of wild-type COS-1 cell rhodopsin and was noncovalently associated with its complementary fragment(s). Further, the CH(1-146) + CH(147-348) rhodopsin showed substantial light-dependent activation of transducin. We conclude that the functional assembly of rhodopsin is mediated by the association of at least three protein-folding domains. Images Fig. 2 PMID:7724540

Ridge, K D; Lee, S S; Yao, L L

1995-01-01

288

Differential Light-induced Responses in Sectorial Inherited Retinal Degeneration.  

PubMed

Retinitis pigmentosa (RP) is a group of genetically and clinically heterogeneous inherited degenerative retinopathies caused by abnormalities of photoreceptors or retinal pigment epithelium in the retina leading to progressive sight loss. Rhodopsin is the prototypical G-protein-coupled receptor located in the vertebrate retina and is responsible for dim light vision. Here, novel M39R and N55K variants were identified as causing an intriguing sector phenotype of RP in affected patients, with selective degeneration in the inferior retina. To gain insights into the molecular aspects associated with this sector RP phenotype, whose molecular mechanism remains elusive, the mutations were constructed by site-directed mutagenesis, expressed in heterologous systems, and studied by biochemical, spectroscopic, and functional assays. M39R and N55K opsins had variable degrees of chromophore regeneration when compared with WT opsin but showed no gross structural misfolding or altered trafficking. M39R showed a faster rate for transducin activation than WT rhodopsin with a faster metarhodopsinII decay, whereas N55K presented a reduced activation rate and an altered photobleaching pattern. N55K also showed an altered retinal release from the opsin binding pocket upon light exposure, affecting its optimal functional response. Our data suggest that these sector RP mutations cause different protein phenotypes that may be related to their different clinical progression. Overall, these findings illuminate the molecular mechanisms of sector RP associated with rhodopsin mutations. PMID:25359768

Ramon, Eva; Cordomí, Arnau; Aguilà, Mònica; Srinivasan, Sundaramoorthy; Dong, Xiaoyun; Moore, Anthony T; Webster, Andrew R; Cheetham, Michael E; Garriga, Pere

2014-12-26

289

The Outer Radiation Belt Injection, Transport, Acceleration and Loss Satellite (ORBITALS): A Canadian Mission to the Inner Magnetosphere  

NASA Astrophysics Data System (ADS)

The Outer Radiation Belt Injection, Transport, Acceleration and Loss Satellite (ORBITALS) mission is proposed as a Canadian Space Agency satellite mission contribution to ILWS. The ORBITALS is currently approved by the CSA for Phase A, and the NASA LWS Mission of Opportunity 4-instrument payload MORE (Mission of Opportunity Radbelt Experiment) for the ORBITALS satellite is undergoing NASA funded Phase A study. The ORBITALS will provide a unique view of the largely previously unexplored inner magnetosphere. Its mission goal to "understand the acceleration, global distribution, and variability of energetic electrons and ions in the inner magnetosphere" is perfectly aligned with the top geospace priority for the LWS and ILWS programs. In a 12 hour low inclination orbit, the ORBITALS will come into once daily apogee conjunctions with the extensive ground-based Canadian Geospace Monitoring (CGSM) instrumentation as well as with GOES East and West. Baseline raised perigee will provide both long outer radiation belt dwell times as well as coverage of the outer-most inner radiation belt. In combination, the ORBITALS-CGSM-GOES conjunctions will provide a unique data set with which to address fundamental radiation belt science questions, such as the competition between ULF and VLF acceleration processes, the role of EMIC and VLF waves in loss, and the relationship between these processes and plasmaspheric cold plasma dynamics. The ORBITALS will also address inter-related science questions about the structure of inner magnetosphere electric and magnetic field structure, plasmaspheric dynamics, including thermal ion injection and loss, and the dynamics of the ring current population in the inner magnetosphere during storms. In combination with the approved NASA LWS RBSP mission, and the proposed Japanese ERG satellite, the ORBITALS-RBSP-ERG three petal constellation will resolve the spatio-temporal ambiguities and global dynamics and morphology of the Earths radiation belts.

Mann, I. R.; Loto'Aniu, T.; Milling, D. K.; Rankin, R.; Fedosejevs, R.; Tsui, Y. Y.; Knudsen, D.; Yau, A.; Balmain, K.; McCabe, D.; Baker, D. N.; Wygant, J. R.; Fennel, J. F.; Kistler, L.; Reeves, G.

2006-12-01

290

A Basin-based Analysis of Global Lake Stress from Scarcity of Sustainable Water Resource  

NASA Astrophysics Data System (ADS)

Lakes are a major storage of surface fresh water readily accessible to human. However, lake water resource is unequally distributed on Earth due to variations of lake abundance, human water demand, and availability of sustainable water supply (primarily, river discharge). This study aims at presenting a global view of contemporary lake stress through analyzing water availability and human demand at fine spatial resolutions. Two scientific questions are progressively explored: i) What is the geographic cross-tabulation of lake distribution vs. population and human water demand? and ii) What is the potential stress of lake water from the scarcity of river discharge? We begin with a straightforward analysis of the spatiotemporal pattern between lake and population distributions. Preliminary results indicate that excluding the extreme climatic zones such as the Pan-Arctic and Tibetan Plateau, lake densities exhibits an intrinsically positive correlation with population density and increase rate. Lake stresses on drainage basin levels are further quantified with integration of river discharge, lake volume, and water withdrawal data. Lake water per capita is computed for each basin. An index of lake water stress (LWS) is developed to characterize the pressure of unit lake/reservoir water exerted from the scarcity of river discharge due to water withdrawal. The revealed LWS pattern provides a spatial-explicit guideline with respect to how lake water is presently in stress and thus potentially redistributed under the baseline of sustainable water scarcity. Several major regions with high LWS values are highlighted to further compare the contributions of human demand and natural water availability to the local lake stress.

Wang, J.; Sheng, Y.

2010-12-01

291

Breeding objectives for pigs in Kenya. II: economic values incorporating risks in different smallholder production systems.  

PubMed

This study estimated economic values for production traits (dressing percentage (DP), %; live weight for growers (LWg), kg; live weight for sows (LWs), kg) and functional traits (feed intake for growers (FEEDg), feed intake for sow (FEEDs), preweaning survival rate (PrSR), %; postweaning survival (PoSR), %; sow survival rate (SoSR), %, total number of piglets born (TNB) and farrowing interval (FI), days) under different smallholder pig production systems in Kenya. Economic values were estimated considering two production circumstances: fixed-herd and fixed-feed. Under the fixed-herd scenario, economic values were estimated assuming a situation where the herd cannot be increased due to other constraints apart from feed resources. The fixed-feed input scenario assumed that the herd size is restricted by limitation of feed resources available. In addition to the tradition profit model, a risk-rated bio-economic model was used to derive risk-rated economic values. This model accounted for imperfect knowledge concerning risk attitude of farmers and variance of input and output prices. Positive economic values obtained for traits DP, LWg, LWs, PoSR, PrSR, SoSR and TNB indicate that targeting them in improvement would positively impact profitability in pig breeding programmes. Under the fixed-feed basis, the risk-rated economic values for DP, LWg, LWs and SoSR were similar to those obtained under the fixed-herd situation. Accounting for risks in the EVs did not yield errors greater than ±50 % in all the production systems and basis of evaluation meaning there would be relatively little effect on the real genetic gain of a selection index. Therefore, both traditional and risk-rated models can be satisfactorily used to predict profitability in pig breeding programmes. PMID:25433647

Mbuthia, Jackson Mwenda; Rewe, Thomas Odiwuor; Kahi, Alexander Kigunzu

2015-02-01

292

Designing 2D arrays for SHM of planar structures: a review  

NASA Astrophysics Data System (ADS)

Monitoring structural integrity of large planar structures that aims at detecting and localizing impact or damage at any point of the structure requires normally a relatively dense network of uniformly distributed ultrasonic sensors. 2-D ultrasonic phased arrays, due to their beam-steering capability and all azimuth angle coverage are a very promising tool for structural health monitoring (SHM) of plate-like structures using Lamb waves (LW). Linear phased arrays that have been proposed for that purpose, produce mirrored image characterized by azimuth dependent resolution, which prevents unequivocal damage localization. 2D arrays do not have this drawback and they are even capable of mode selectivity when generating and receiving LWs. Performance of 2D arrays depends on their topology as well as the number of elements (transducers) used and their spacing in terms of wavelength. In this paper we propose a consistent methodology for three-step: theoretical, numerical and experimental investigation of a diversity of 2D array topologies in SHM applications. In the first step, the theoretical evaluation is performed using frequency-dependent structure transfer function (STF). STF that defines linear propagation of different LWs modes through the dispersive medium enables theoretical investigation of the particular array performance for a predefined tone-burst excitation signal. A dedicated software tool has been developed for the numerical evaluation of 2D array directional characteristics (beampattern) in a specific structure. The simulations are performed using local interaction simulation approach (LISA), implemented using NVIDIA CUDA graphical computation unit (GPU), which enables time-efficient 3D simulations of LWs propagation. Beampatterns of a 2D array can be to some extend evaluated analytically and using numerical simulations; in most cases, however, they require experimental verification. Using scanning laser vibrometer is proposed for that purpose, in a setup where LWs, excited by PZT transmitters of the investigated array are sensed in multiple points corresponding to the locations of the 2D array receiving elements. A virtual receiving sub-array is created in this way and the performance of various array architectures in the reception mode can be evaluated experimentally without the need of physical prototype; a change of topology requires only straightforward modification of the measurement points distribution at the tested structure. For illustration, beampatterns of three symmetrical 2D topologies, i.e., circular, star-shaped and spiralshaped, will be examined in the paper and compared in terms of their beam-width and side-lobes level. The effect of apodization applied to the array elements will be also investigated.

Stepinski, Tadeusz; Ambrozinski, Lukasz; Uhl, Tadeusz

2013-04-01

293

A statistical study of conductance properties in one-dimensional quantum wires, focusing on the 0.7 anomaly  

E-print Network

. Ritchie1, M. J. Kelly1,2, and C. G. Smith1 1Cavendish Laboratory, Department of Physics, University of Cambridge, J. J. Thomson Avenue, Cambridge, CB3 0HE, United Kingdom 2Centre for Advanced Photonics and Electronics, Electrical Engineering Division... . Owen and K. J. Thomas for useful discussions, and R. D. Hall for e-beam exposure. ? Corresponding author. E-mail address: lws22@cam.ac.uk 9[1] T. J. Thornton, M. Pepper, H. Ahmed, D. Andrews, and G. J. Davies, Phys. Rev. Lett. 56, 1198 (1986). [2] B. J...

Smith, L. W.; Al-Taie, H.; Sfigakis, F.; See, P.; Lesage, A. A. J.; Xu, B.; Griffiths, J. P.; Beere, H. E.; Jones, G. A. C.; Ritchie, D. A.; Kelly, M. J.; Smith, C. G.

2014-07-28

294

The [CII] and [OI] emission lines in NGC6946 and NGC1313  

NASA Astrophysics Data System (ADS)

The [CII (158 ?m)] fine structure line, which is the principal cooling line of the atomic gas, in two nearby galaxies observed with LWS on board ISO is compared to dust and HI gas emission and heating intensity. The relation between photoelectric effect on different grains populations, dust and gas heating found for a sample of 60 normal galaxies for which global [CII] measurements are available, still holds on scale of ~1.5 kpc. We also succeed in detecting cooling from a low density diffuse atomic gas associated with the diffuse optical disk in both galaxies, accounting typically for ~ 30-40% of the total [CII] emission.

Contursi, A.; Brauher, J.; Helou, G.

295

The Second NWRA Flare-Forecasting Comparison Workshop: Preliminary Results  

NASA Astrophysics Data System (ADS)

The Second NWRA Workshop to compare methods of solar flare forecasting was held 2-4 April 2013 in Boulder, CO. Many researchers who are active in the field participated, and provided their methods' prediction results on standardized datasets. We discuss what is necessary to make meaningful comparisons of methods, focusing on techniques for removing bias and estimating random errors, and present preliminary method comparisons based on standardized skill scores. Funding for the workshop and the data analysis was provided by NASA/LWS contract NNH09CE72C and NASA/GI contract NNH12CG10C.

Barnes, Graham; Leka, K. D.; Flare Forecasting Comparison Group

2013-07-01

296

Space Weather Monitoring with DSCOVR and Beyond  

NASA Astrophysics Data System (ADS)

With the NOAA/NASA DSCOVR spacecraft launched around 2015, continued near-Earth solar wind monitoring will be assured. However, to provide more than the current 30-45 minutes warning time of incoming solar transients, newer platforms are required. Solar sail missions would orbit an artificial 1st Lagrange point nearly doubling the current warning time. Four or five LWS Solar Sentinels orbiting the Sun inside 0.5 AU would provide warning times close to 1 day. The required scientific understanding is already at hand to take full advantage of such new missions. DSCOVR and these new missions will be discussed in detail.

Szabo, A.

2013-05-01

297

The Living With a Star Space Environment Testbed Program  

NASA Technical Reports Server (NTRS)

NASA has initiated the Living with a Star (LWS) Program to develop the scientific understanding to address the aspects of the Connected Sun-Earth system that affects life and society. The Program Architecture includes science missions, theory and modeling and Space Environment Testbeds (SET). This current paper discusses the Space Environment Testbeds. The goal of the SET program is to improve the engineering approach to accomodate and/or mitigate the effects of solar variability on spacecraft design and operations. The SET Program will infuse new technologies into the space programs through collection of data in space and subsequent design and validation of technologies. Examples of these technologies are cited and discussed.

Barth, Janet; LaBel, Kenneth; Day, John H. (Technical Monitor)

2001-01-01

298

Mechanical properties of polyurethane films prepared from liquefied wood with polymeric MDI  

Microsoft Academic Search

Sugi (Cryptomeria japonica D.Don) wood was liquefied using glycerol–PEG#400 co-solvent as reaction reagent in the presence of sulfuric acid for 75 min, at 150°C. The liquefied woods (LWs) obtained comprised of 9.6–29.8% dissolution wood and had a hydroxyl number of 329.1–278.7 mg KOH\\/g and viscosity of 0.33–31.6 Pa s at 25°C. Polyurethane (PU) films were prepared by a solution-casting technique

Y Kurimoto; M Takeda; A Koizumi; S Yamauchi; S Doi; Y Tamura

2000-01-01

299

The relation of cold temperature to seedling blight incited by seed-borne and soil-borne organisms  

E-print Network

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Stewart, Robert Blaylock

2012-06-07

300

The Living With a Star Space Environment Testbed Experiments  

NASA Technical Reports Server (NTRS)

The focus of the Living With a Star (LWS) Space Environment Testbed (SET) program is to improve the performance of hardware in the space radiation environment. The program has developed a payload for the Air Force Research Laboratory (AFRL) Demonstration and Science Experiments (DSX) spacecraft that is scheduled for launch in August 2015 on the SpaceX Falcon Heavy rocket. The primary structure of DSX is an Evolved Expendable Launch Vehicle (EELV) Secondary Payload Adapter (ESPA) ring. DSX will be in a Medium Earth Orbit (MEO). This oral presentation will describe the SET payload.

Xapsos, Michael A.

2014-01-01

301

Molecular mechanisms of rhodopsin retinitis pigmentosa and the efficacy of pharmacological rescue.  

PubMed

Variants of rhodopsin, a complex of 11-cis retinal and opsin, cause retinitis pigmentosa (RP), a degenerative disease of the retina. Trafficking defects due to rhodopsin misfolding have been proposed as the most likely basis of the disease, but other potentially overlapping mechanisms may also apply. Pharmacological therapies for RP must target the major disease mechanism and contend with overlap, if it occurs. To this end, we have explored the molecular basis of rhodopsin RP in the context of pharmacological rescue with 11-cis retinal. Stable inducible cell lines were constructed to express wild-type opsin; the pathogenic variants T4R, T17M, P23A, P23H, P23L, and C110Y; or the nonpathogenic variants F220L and A299S. Pharmacological rescue was measured as the fold increase in rhodopsin or opsin levels upon addition of 11-cis retinal during opsin expression. Only Pro23 and T17M variants were rescued significantly. C110Y opsin was produced at low levels and did not yield rhodopsin, whereas the T4R, F220L, and A299S proteins reached near-wild-type levels and changed little with 11-cis retinal. All of the mutant rhodopsins exhibited misfolding, which increased over a broad range in the order F220L, A299S, T4R, T17M, P23A, P23H, P23L, as determined by decreased thermal stability in the dark and increased hydroxylamine sensitivity. Pharmacological rescue increased as misfolding decreased, but was limited for the least misfolded variants. Significantly, pathogenic variants also showed abnormal photobleaching behavior, including an increased ratio of metarhodopsin-I-like species to metarhodopsin-II-like species and aberrant photoproduct accumulation with prolonged illumination. These results, combined with an analysis of published biochemical and clinical studies, suggest that many rhodopsin variants cause disease by affecting both biosynthesis and photoactivity. We conclude that pharmacological rescue is promising as a broadly effective therapy for rhodopsin RP, particularly if implemented in a way that minimizes the photoactivity of the mutant proteins. PMID:19913029

Krebs, Mark P; Holden, David C; Joshi, Parth; Clark, Charles L; Lee, Andrew H; Kaushal, Shalesh

2010-02-01

302

Bridging the gulf between correlated random walks and Lévy walks: autocorrelation as a source of Lévy walk movement patterns  

PubMed Central

For many years, the dominant conceptual framework for describing non-oriented animal movement patterns has been the correlated random walk (CRW) model in which an individual's trajectory through space is represented by a sequence of distinct, independent randomly oriented ‘moves’. It has long been recognized that the transformation of an animal's continuous movement path into a broken line is necessarily arbitrary and that probability distributions of move lengths and turning angles are model artefacts. Continuous-time analogues of CRWs that overcome this inherent shortcoming have appeared in the literature and are gaining prominence. In these models, velocities evolve as a Markovian process and have exponential autocorrelation. Integration of the velocity process gives the position process. Here, through a simple scaling argument and through an exact analytical analysis, it is shown that autocorrelation inevitably leads to Lévy walk (LW) movement patterns on timescales less than the autocorrelation timescale. This is significant because over recent years there has been an accumulation of evidence from a variety of experimental and theoretical studies that many organisms have movement patterns that can be approximated by LWs, and there is now intense debate about the relative merits of CRWs and LWs as representations of non-orientated animal movement patterns. PMID:20630882

Reynolds, Andy M.

2010-01-01

303

Current Status on NASA's Living With a Star Program  

NASA Astrophysics Data System (ADS)

Living With a Star is a space weather-focused and application-driven research program. Its goal is to develop the scientific understanding necessary to effectively address those aspects of the connected Sun-Earth system that directly affect life and society. This program is part of the Sun-Earth Connection (SEC) theme within the office of Space Science. Living With a Star is a cross-cutting program whose goals and objectives have the following links to each of the four NASA Strategic Enterprises: Space Science: LWS quantifies the physics, dynamics, and behavior of the only stellar/planetary system we can see at a close distance. Earth Science: LWS improves understanding of the effects of solar variability and disturbances on terrestrial climate change. Human Space Flight: LWS provides data and scientific understanding required for advanced warning of energetic particle events that affect the safety of humans in space. Aeronautics and Space Transportation: LWS provides detailed characterization of radiation environments useful in the design of more reliable electronic components for air and space transportation system. LWS Program is implemented by a sequence of inter-related science missions, space environment test bed and targeted research and technology. 1) A space weather research network of spacecraft will provide continuous observations of the Sun-Earth system for interlocking, dual use, scientific and applications research. Flight of a Solar Dynamics Observatory (launch 2008) to: - Probe solar interior, especially region where the dynamo is located, vs time to unravel physics of ``engine'' driving solar variability. -Track, for first time, solar active regions/solar storm regions simultaneously above and below solar surface to understand development and triggering of explosive events (Flares, Coronal Mass Ejections). Flight of Solar Sentinels, launch before and around next solar max to provide global view of the heliosphere, track solar active regions over entire sun, including for the first time the backside of Sun and describe the evolution of eruptions and flares from the Sun to Earth to Mars and beyond. Flight of Magnetospheric and Ionospheric Storm Probes, launch around solar max, geospace ``buoys'' in critical regions of Earth's space environment to determine its global and local response to solar variability. 2) A special data analysis and modeling program (Targeted Research & Technology) targeted at (1) obtaining a Sun-Earth systems model, (2) improving knowledge of space environmental conditions and variations over the solar cycle, (3) developing techniques and models for predicting solar/geospace disturbances which affect human technology, and (4) assimilating data from networks of spacecraft. 3) Orbital Technology Testbeds (Space Environment Testbeds) for low cost validation of rad-hard and rad-tolerant systems in high radiation orbits. - Implemented as missions of opportunity via cost-sharing partnerships with various international and national partners 4) Establishing and expanding partnerships for interdisciplinary science and applications with other NASA programs (Earth Science, Human Space Flight, Life Sciences), with other federal agencies (via interagency for National Space Weather Program, NOAA, NSF, DOE), international partners, academic community, and industry to obtain synergism and address common needs.

Guhathakurta, M.; Stcyr, O. C.

304

Southern White English: The Changing Verb Phrase.  

ERIC Educational Resources Information Center

In a sociolinguistic study of the verb phrase in Southern White English, a pattern of change in progress was observed. The 14 variables studied showed that certain variants were increasing, others decreasing, and yet others stable across time within the community, and that each variable's change was progressing in a wave sensitive to age, social…

Feagin, Louise Crawford

305

Thermal lensing in recycling interferometric gravitational wave detectors  

Microsoft Academic Search

Thermal lensing limits the performance of advanced interferometric gravitational wave detectors that use high light powers. We evaluate the effects of thermal lensing in such systems and estimate their gravitational wave sensitivity assuming that fused silica optical substrates are employed. Although useful sensitivity can be achieved with established designs, the new technique of resonant sideband extraction is most promising for

K. A. Strain; K. Danzmann; J. Mizuno; P. G. Nelson; A. Rüdiger; R. Schilling; W. Winkler

1994-01-01

306

QM/MM Structure, Enantioselectivity and Spectroscopy of HydroxyRetinals and Insights into the Evolution of Color Vision in Small White Butterflies  

PubMed Central

Since Vogt’s discovery of A3-retinal or 3-hydroxyretinal in insects in 1983 and Matsui’s discovery of A4-retinal or 4-hydroxyretinal in firefly squid in 1988, hydroxyretinal-protein interactions mediating vision remains largely unexplored. In the present study, A3- and A4-retinals are theoretically incorporated into squid and bovine visual pigments using the hybrid quantum mechanics/molecular mechanics (SORCI+Q//B3LYP/6-31G(d):Amber96) method and insights into the structure, enantioselectivity and spectroscopy are gathered and presented for the first time. Contrary to general perception, our findings rule out the formation of hydrogen bond between the hydroxyl-bearing ?-ionone ring part of retinal and opsin. Compared to A1-pigments, A3- and A4-pigments exhibit slightly blue-shifted absorption maxima due to increase in bond-length alternation of the hydroxyretinal. We suggest that, (i) The binding site of firefly squid (Watasenia scintillians) opsin is very similar to that of the Japanese common squid (Todarodes pacificus) opsin, (ii) Molecular mechanism of spectral tuning in the small white butterflies involve sites S116, T185 and breaking of hydrogen bond between sites E180 and T185; and finally, (iii) A3-retinal may have occurred during the conversion of A1- to A2-retinal and insects may have acquired them, in order to absorb light in the blue-green wavelength region and to speed up the G-protein signaling cascade. PMID:22087641

Sekharan, Sivakumar; Yokoyama, Shozo

2011-01-01

307

Immuno-Histochemical Analysis of Rod and Cone Reaction to RPE65 Deficiency in the Inferior and Superior Canine Retina  

PubMed Central

Mutations in the RPE65 gene are associated with autosomal recessive early onset severe retinal dystrophy. Morphological and functional studies indicate early and dramatic loss of rod photoreceptors and early loss of S-cone function, while L and M cones remain initially functional. The Swedish Briard dog is a naturally occurring animal model for this disease. Detailed information about rod and cone reaction to RPE65 deficiency in this model with regard to their location within the retina remains limited. The aim of this study was to analyze morphological parameters of cone and rod viability in young adult RPE65 deficient dogs in different parts of the retina in order to shed light on local disparities in this disease. In retinae of affected dogs, sprouting of rod bipolar cell dendrites and horizontal cell processes was dramatically increased in the inferior peripheral part of affected retinae, while central inferior and both superior parts did not display significantly increased sprouting. This observation was correlated with photoreceptor cell layer thickness. Interestingly, while L/M cone opsin expression was uniformly reduced both in the superior and inferior part of the retina, S-cone opsin expression loss was less severe in the inferior part of the retina. In summary, in retinae of young adult RPE65 deficient dogs, the degree of rod bipolar and horizontal cell sprouting as well as of S-cone opsin expression depends on the location. As the human retinal pigment epithelium (RPE) is pigmented similar to the RPE in the inferior part of the canine retina, and the kinetics of photoreceptor degeneration in humans seems to be similar to what has been observed in the inferior peripheral retina in dogs, this area should be studied in future gene therapy experiments in this model. PMID:24466015

Klein, Daniela; Mendes-Madeira, Alexandra; Schlegel, Patrice; Rolling, Fabienne; Lorenz, Birgit; Haverkamp, Silke; Stieger, Knut

2014-01-01

308

Effect of G Protein–Coupled Receptor Kinase 1 (Grk1) Overexpression on Rod Photoreceptor Cell Viability  

PubMed Central

Purpose. Photoreceptor rhodopsin kinase (Rk, G protein–dependent receptor kinase 1 [Grk1]) phosphorylates light-activated opsins and channels them into an inactive complex with visual arrestins. Grk1 deficiency leads to human retinopathy and heightened susceptibility to light-induced photoreceptor cell death in the mouse. The goal of this study was to determine whether excess Grk1 activity is protective against photoreceptor cell death. Methods. Grk1-overexpressing transgenic mice (Grk1+) were generated by using a bacterial artificial chromosome (BAC) construct containing mouse Grk1, along with its flanking sequences. Quantitative reverse transcription-PCR, immunoblot analysis, immunostaining, and activity assays were combined with electrophysiology and morphometric analysis, to evaluate Grk1 overexpression and its effect on physiologic and morphologic retinal integrity. Morphometry and nucleosome release assays measured differences in resistance to photoreceptor cell loss between control and transgenic mice exposed to intense light. Results. Compared with control animals, the Grk1+ transgenic line had approximately a threefold increase in Grk1 transcript and immunoreactive protein. Phosphorylated opsin immunochemical staining and in vitro phosphorylation assays confirmed proportionately higher Grk1 enzyme activity. Grk1+ mice retained normal rod function, normal retinal appearance, and lacked evidence of spontaneous apoptosis when reared in cyclic light. In intense light, Grk1+ mice showed photoreceptor damage, and their susceptibility was more pronounced than that of control mice with prolonged exposure times. Conclusions. Enhancing visual pigment deactivation does not appear to protect against apoptosis; however, excess flow of opsin into the deactivation pathway may actually increase susceptibility to stress-induced cell death similar to some forms of retinal degeneration. PMID:19834036

Whitcomb, Tiffany; Sakurai, Keisuke; Brown, Bruce M.; Young, Joyce E.; Sheflin, Lowell; Dlugos, Cynthia; Craft, Cheryl M.; Kefalov, Vladimir J.

2010-01-01

309

Cone photoreceptor types in zebrafish are generated by symmetric terminal divisions of dedicated precursors  

PubMed Central

Proper functioning of sensory systems requires the generation of appropriate numbers and proportions of neuronal subtypes that encode distinct information. Perception of color relies on signals from multiple cone photoreceptor types. In cone-dominated retinas, each cone expresses a single opsin type with peak sensitivity to UV, long (L) (red), medium (M) (green), or short (S) (blue) wavelengths. The modes of cell division generating distinct cone types are unknown. We report here a mechanism whereby zebrafish cone photoreceptors of the same type are produced by symmetric division of dedicated precursors. Transgenic fish in which the thyroid hormone receptor ?2 (tr?2) promoter drives fluorescent protein expression before L-cone precursors themselves are produced permitted tracking of their division in vivo. Every L cone in a local region resulted from the terminal division of an L-cone precursor, suggesting that such divisions contribute significantly to L-cone production. Analysis of the fate of isolated pairs of cones and time-lapse observations suggest that other cone types can also arise by symmetric terminal divisions. Such divisions of dedicated precursors may help to rapidly attain the final numbers and proportions of cone types (L > M, UV > S) in zebrafish larvae. Loss- and gain-of-function experiments show that L-opsin expression requires tr?2 activity before cone differentiation. Ectopic expression of tr?2 after cone differentiation produces cones with mixed opsins. Temporal differences in the onset of tr?2 expression could explain why some species have mixed, and others have pure, cone types. PMID:23980162

Suzuki, Sachihiro C.; Bleckert, Adam; Williams, Philip R.; Takechi, Masaki; Kawamura, Shoji; Wong, Rachel O. L.

2013-01-01

310

From Blue Light to Clock Genes in Zebrafish ZEM-2S Cells  

PubMed Central

Melanopsin has been implicated in the mammalian photoentrainment by blue light. This photopigment, which maximally absorbs light at wavelengths between 470 and 480 nm depending on the species, is found in the retina of all classes of vertebrates so far studied. In mammals, melanopsin activation triggers a signaling pathway which resets the circadian clock in the suprachiasmatic nucleus (SCN). Unlike mammals, Drosophila melanogaster and Danio rerio do not rely only on their eyes to perceive light, in fact their whole body may be capable of detecting light and entraining their circadian clock. Melanopsin, teleost multiple tissue (tmt) opsin and others such as neuropsin and va-opsin, are found in the peripheral tissues of Danio rerio, however, there are limited data concerning the photopigment/s or the signaling pathway/s directly involved in light detection. Here, we demonstrate that melanopsin is a strong candidate to mediate synchronization of zebrafish cells. The deduced amino acid sequence of melanopsin, although being a vertebrate opsin, is more similar to invertebrate than vertebrate photopigments, and melanopsin photostimulation triggers the phosphoinositide pathway through activation of a Gq/11-type G protein. We stimulated cultured ZEM-2S cells with blue light at wavelengths consistent with melanopsin maximal absorption, and evaluated the time course expression of per1b, cry1b, per2 and cry1a. Using quantitative PCR, we showed that blue light is capable of slightly modulating per1b and cry1b genes, and drastically increasing per2 and cry1a expression. Pharmacological assays indicated that per2 and cry1a responses to blue light are evoked through the activation of the phosphoinositide pathway, which crosstalks with nitric oxide (NO) and mitogen activated protein MAP kinase (MAPK) to activate the clock genes. Our results suggest that melanopsin may be important in mediating the photoresponse in Danio rerio ZEM-2S cells, and provide new insights about the modulation of clock genes in peripheral clocks. PMID:25184495

Ramos, Bruno C. R.; Moraes, Maria Nathália C. M.; Poletini, Maristela O.; Lima, Leonardo H. R. G.; Castrucci, Ana Maria L.

2014-01-01

311

Transducin-alpha C-terminal mutations prevent activation by rhodopsin: a new assay using recombinant proteins expressed in cultured cells.  

PubMed Central

We have measured the activation by recombinant rhodopsin of the alpha-subunit (alpha 1) of retinal transducin (Gt, also recombinant) using a new assay. Cultured cells are transiently transfected with DNAs encoding opsin and the three subunits of Gt (alpha t, beta 1 and gamma 1). In the microsomes of these cells, incubated with 11-cis-retinal, light causes the rapid activation of Gt, as measured by the ability of GTP gamma S to protect alpha t fragments from proteolytic degradation. The activation of Gt is also observed when all-trans-retinal is added to microsomes under constant illumination. Activation depends on both opsin and retinal. Opsin mutants with known defects in activating Gt show similar defects in this assay. alpha t mutations that mimic the corresponding mutations in the alpha-subunit of Gs also produce qualitatively similar effects in this assay. As a first step in a strategy aimed at exploring the relationships between structure and function in the interactions of receptors with G proteins, we tested mutant alpha t proteins with alanine substituted for each of the 10 amino acids at the C-terminus, a region known to be crucial for interactions with rhodopsin. Alanine substitution at four positions moderately (K341) or severely (L344, G348, L349) impairs the susceptibility of alpha 1 to activation by rhodopsin. All four mutants retain their ability to be activated by AIF-4. Two other substitutions (N343 and F350) resulted in very mild defects, while substitutions at the remaining four positions (E342, K345, D346 and C347) had no effect. In combination with previous observations, these results constrain models of the interaction of the C-terminus of alpha t with rhodopsin. Images PMID:7556089

Garcia, P D; Onrust, R; Bell, S M; Sakmar, T P; Bourne, H R

1995-01-01

312

Early Degeneration of Photoreceptor Synapse in Ccl2/Cx3cr1-Deficient Mice on Crb1rd8 Background  

PubMed Central

Photoreceptor ribbon synapse releases glutamate to postsynaptic targets. The synaptic ribbon may play multiple roles in ribbon synapse development, synaptic vesicle recycling, and synaptic transmission. Age-related macular degeneration (AMD) patients appear to have fewer or no detectable synaptic ribbons as well as abnormal swelling in the photoreceptor terminals in the macula. However, reports on changes of photoreceptor synapses in AMD are scarce and photoreceptor type and quantity affected in early AMD is still unclear. Here, we employed multiple anatomical techniques to investigate these questions in Ccl2?/?/Cx3cr1?/? mouse on Crb1rd8 background (DKO rd8) at one month of age. We found that approximately 17% of photoreceptors over the focal lesion were lost. Immunostaining for synapse-associated proteins (CtBP2, synaptophysin, and vesicular glutamate transporter 1) showed significantly reduced expression and ectopic localization. Cone opsins demonstrated dramatic reduction in expression (S-opsins) and extensive mislocalization (M-opsins). Quantitative ultrastructural analysis confirmed a significant decrease in the number of cone terminals and nuclei, numerous vacuoles in remaining cone terminals, reduction in the number of synaptic ribbons in photoreceptor terminals, and ectopic rod ribbon synapses. In addition, glutamate receptor immunoreactivity on aberrant sprouting of rod bipolar cells and horizontal cells were identified at the ectopic synapses. These results indicate that synaptic alterations occur at the early stages of disease and cones are likely more susceptible to damage caused by DKO rd8 mutation. They provide a new insight into potential mechanism of vision function lost due to synaptic degeneration before cell death in the early Stages of AMD. PMID:23592324

Zhang, Jun; Tuo, Jingsheng; Cao, Xiaoguan; Shen, Defen; Li, Wei; Chan, Chi-Chao

2013-01-01

313

Evolutionary tinkering with visual photoreception.  

PubMed

Eyes have evolved many times, and arthropods and vertebrates share transcription factors for early development. Moreover, the photochemistry of vision in all eyes employs an opsin and the isomerization of a retinoid from the 11-cis to the all-trans configuration. The opsins, however, have associated with several different G proteins, initiating hyperpolarizing and depolarizing conductance changes at the photoreceptor membrane. Beyond these obvious instances of homology, much of the evolutionary story is one of tinkering, producing a great variety of morphological forms and variation within functional themes. This outcome poses a central issue in the convergence of evolutionary and developmental biology: what are the heritable features in the later stages of development that give natural selection traction in altering phenotypic outcomes? This paper discusses some results of evolutionary tinkering where this question arises and, in some cases, where the reasons for particular outcomes and the role of adaptation may not be understood. Phenotypic features include: the exploitation of microvilli in rhabdomeric photoreceptors for detecting the plane of polarized light; different instances of retinoid in the visual pigment; examples of the many uses of accessory pigments in tuning the spectral sensitivity of photoreceptors; selection of opsins in tuning sensitivity in aquatic environments; employing either reflection or refraction in the optics of compound eyes; the multiple ways of constructing images in compound eyes; and the various ways of regenerating 11-cis retinals to maintain visual sensitivity. Evolution is an irreversible process, but tinkering may recover some lost functions, albeit by new mutational routes. There is both elegance and intellectual coherence to the natural processes that produce such variety and functional complexity. But marginalizing the teaching of evolution in public education is a continuing social and political problem that contributes to the reckless capacity of humans to alter the planet without trying to understand how nature works. PMID:22391141

Goldsmith, Timothy H

2013-03-01

314

Residue-specific millisecond to microsecond fluctuations in bacteriorhodopsin induced by disrupted or disorganized two-dimensional crystalline lattice, through modified lipid–helix and helix–helix interactions, as revealed by 13C NMR  

Microsoft Academic Search

We have recorded 13C NMR spectra of [3-13C]-, [1-13C]Ala-, and [1-13C]Val-labeled bacteriorhodopsin (bR), W80L and W12L mutants and bacterio-opsin (bO) from retinal-deficient E1001 strain, in order to examine the possibility of their millisecond to microsecond local fluctuations with correlation time in the order of 10?4 to 10?5 s, induced or prevented by disruption or assembly of two-dimensional (2D) crystalline lattice,

Hazime Saitô; Takahiro Tsuchida; Keizi Ogawa; Tadashi Arakawa; Satoru Yamaguchi; Satoru Tuzi

2002-01-01

315

Molecular recognition of chromophore molecules to amine terminated surfaces  

NASA Astrophysics Data System (ADS)

We report the design and characterization of quartz surfaces that can bind to three retinal based chromophores. The amine terminated surfaces were engineered in order to mimic the environment of the opsin protein that accommodates binding of chromophore molecules in the human eye. Each surface coupling step was characterized by water contact angle measurements, ellipsometry, atomic force microscopy, X-ray photoelectron spectroscopy, and transmission infrared spectroscopy. The spectroscopic techniques confirmed that the three chromophore molecules can bind to the surface using a Schiff base mode. Our data suggests that the availability of the amine groups on the surface is critical in the accommodation of the binding of different chromophores.

Flores-Perez, Rosangelly; Ivanisevic, Albena

2007-02-01

316

The ecoresponsive genome of Daphnia pulex  

SciTech Connect

This document provides supporting material related to the sequencing of the ecoresponsive genome of Daphnia pulex. This material includes information on materials and methods and supporting text, as well as supplemental figures, tables, and references. The coverage of materials and methods addresses genome sequence, assembly, and mapping to chromosomes, gene inventory, attributes of a compact genome, the origin and preservation of Daphnia pulex genes, implications of Daphnia's genome structure, evolutionary diversification of duplicated genes, functional significance of expanded gene families, and ecoresponsive genes. Supporting text covers chromosome studies, gene homology among Daphnia genomes, micro-RNA and transposable elements and the 46 Daphnia pulex opsins. 36 figures, 50 tables, 183 references.

Colbourne, John K.; Pfrender, Michael E.; Gilbert, Donald; Thomas, W. Kelley; Tucker, Abraham; Oakley, Todd H.; Tokishita, Shinichi; Aerts, Andrea; Arnold, Georg J.; Basu, Malay Kumar; Bauer, Darren J.; Caceres, Carla E.; Carmel, Liran; Casola, Claudio; Choi, Jeong-Hyeon; Detter, John C.; Dong, Qunfeng; Dusheyko, Serge; Eads, Brian D.; Frohlich, Thomas; Geiler-Samerotte, Kerry A.; Gerlach, Daniel; Hatcher, Phil; Jogdeo, Sanjuro; Krijgsveld, Jeroen; Kriventseva, Evgenia V; Kültz, Dietmar; Laforsch, Christian; Lindquist, Erika; Lopez, Jacqueline; Manak, Robert; Muller, Jean; Pangilinan, Jasmyn; Patwardhan, Rupali P.; Pitluck, Samuel; Pritham, Ellen J.; Rechtsteiner, Andreas; Rho, Mina; Rogozin, Igor B.; Sakarya, Onur; Salamov, Asaf; Schaack, Sarah; Shapiro, Harris; Shiga, Yasuhiro; Skalitzky, Courtney; Smith, Zachary; Souvorov, Alexander; Sung, Way; Tang, Zuojian; Tsuchiya, Dai; Tu, Hank; Vos, Harmjan; Wang, Mei; Wolf, Yuri I.; Yamagata, Hideo; Yamada, Takuji; Ye, Yuzhen; Shaw, Joseph R.; Andrews, Justen; Crease, Teresa J.; Tang, Haixu; Lucas, Susan M.; Robertson, Hugh M.; Bork, Peer; Koonin, Eugene V.; Zdobnov, Evgeny M.; Grigoriev, Igor V.; Lynch, Michael; Boore, Jeffrey L.

2011-02-04

317

Hot-electron generation by 'cavitating' Langmuir turbulence in the nonlinear stage of the two-plasmon-decay instability  

SciTech Connect

The kinetic reduced-description particle-in-cell simulation technique has been applied to study the nonlinear stage of two-plasmon-decay (TPD) instability in an inhomogeneous plasma driven by crossed laser beams. The TPD instability is found to be a prolific generator of 'cavitating' Langmuir turbulence. Langmuir 'cavitons'-localized longitudinal electric fields, oscillating near the local electron plasma frequency, trapped in ponderomotive density depressions-collapse to dimensions of a few electron Debye lengths, where the electric field energy is collisionlessly transferred to electron kinetic energy. The resulting hot electrons can attain instantaneous temperatures up to 100 keV with net suprathermal heat flux out of the system of up to a few percent of the input laser energy. Scaling laws for this hot-electron generation by TPD, in regimes motivated by recent experiments on the Omega laser, were presented recently by Vu et al. (H. X. Vu, D. F. DuBois, D. A. Russell, and J. F. Myatt, Phys. Plasmas 19, 102703 (2012)). This paper concentrates on the microscopic mechanisms for hot-electron generation. The spatial distribution of the maxima of the electric field envelope modulus is found to be very spiky, with the distribution of electric field envelope maxima obeying Gaussian statistics. The cavitons are produced in density-depletion trenches produced by the combined ponderomotive interference of the crossed laser beams and the ponderomotive beats of the primary backward-going TPD Langmuir waves (LWs) resulting from the crossed beams. The Langmuir turbulence is strongest in the electron-density region near 0.241 Multiplication-Sign the laser's critical density, where the forward LWs from the crossed-beam TPD are degenerate. Nucleation of cavitons is assisted by the modulation of the electron density in the trenches, which in turn is caused by the beating of the common forward-going LW and the pair of backward-going LWs. The autocorrelation function of the LW envelope field provides a near-universal shape for intense cavitons-in the neighborhood of the local field maxima. The hot-electron temperature is found to be approximately a linear function of the 'caviton temperature' determined from the Gaussian distribution of caviton maxima. These diagnostics provide strong evidence for the importance of Langmuir caviton collapse in the generation of hot electrons by TPD. Extended Zakharov model predictions for TPD exhibit the same qualitative phenomena.

Vu, H. X. [Department of Electrical and Computer Engineering, University of California, San Diego, La Jolla, California 92093 (United States); DuBois, D. F. [Lodestar Research Corporation, Boulder, Colorado 80301 (United States); Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States); Russell, D. A. [Lodestar Research Corporation, Boulder, Colorado 80301 (United States); Myatt, J. F. [Laboratory for Laser Energetics, University of Rochester, Rochester, New York 14623 (United States)

2012-10-15

318

Genetics of residual feed intake in growing pigs: Relationships with production traits, and nitrogen and phosphorus excretion traits.  

PubMed

Residual feed intake (RFI) is defined as the difference between the observed ADFI and the ADFI predicted from production and maintenance requirements. The objectives of this study were to evaluate RFI as a selection criterion to improve feed efficiency and its potential to reduce N and P excretion in 4 pig breeds. Data were collected between 2000 and 2009 in French central test stations for 2 dam breeds [French Landrace (LR) and Large White (LWD)], and 2 sire breeds [Large White (LWS) and Piétrain (PP)]. Numbers of recorded pigs were 6407, 10,694, 2342, and 2448 for the LR, LWD, LWS, and PP breeds, respectively. All PP animals were genotyped for the halothane mutation. This data set was used to calculate RFI equations for each of the 4 breeds, and to estimate genetic parameters for RFI together with growth, carcass, and meat quality traits, and N and P excretion during the test period (35 to 110 kg BW). The RFI explained 20.1% in PP, 26.5% in LWS, 27.6% in LWD, and 29.5% in LR of the phenotypic variability of ADFI. The PP breed differed from the others in this respect, probably due to a lower impact of the variation of body composition on ADFI. Heritability estimates of RFI ranged from 0.21 ± 0.03 (LWD) to 0.33 ± 0.06 (PP) depending on the breed. Heritabilities of N and P excretion traits ranged from 0.29 ± 0.06 to 0.40 ± 0.06. The RFI showed positive genetic correlations with feed conversion ratio (FCR) and excretion traits, these correlations being greater in the sire breeds (from 0.57 to 0.86) than in the dam breeds (from 0.38 to 0.53). Compared with FCR, RFI had weaker genetic correlations with carcass composition, growth rate, and excretion traits. Estimates of genetic correlations between FCR and excretion traits were very close to 1 for all breeds. Finally, excretion traits were, at the genetic level, correlated positively with ADFI, negatively with growth rate and carcass leanness, whereas the halothane n mutation in PP was shown to reduce N and P excretion levels. To conclude, new selection indexes including RFI can be envisaged to efficiently disentangle the responses to selection on growth rate and body composition from those on feed efficiency, with favorable impacts on N and P excretions, particularly in sire pig breeds. However, the switch from FCR to RFI in selection indexes should not resolve the genetic antagonism between feed efficiency and meat quality. PMID:23482579

Saintilan, R; Mérour, I; Brossard, L; Tribout, T; Dourmad, J Y; Sellier, P; Bidanel, J; van Milgen, J; Gilbert, H

2013-06-01

319

Cryogenic mechanisms for scanning and interchange of the Fabry-Perot interferometers in the ISO long wavelength spectrometer  

NASA Technical Reports Server (NTRS)

The Infrared Space Observatory (ISO) is an ESA cornerstone mission for infrared astronomy. Schedules for launch in 1993, its four scientific instruments will provide unprecedented sensitivity and spectral resolution at wavelengths which are inaccessible using ground-based techniques. One of these, the Long Wavelength Spectrometer (LWS), will operate in the 45 to 180 micron region (Emery et. al., 1985) and features two Fabry-Perot interferometers mounted on an interchange mechanism. The entire payload module of the spacecraft, comprising the 60 cm telescope and the four focal plane instruments, is maintained at 2 to 4 K by an onboard supply of liquid helium. The mechanical design and testing of the cryogenic interferometer and interchange mechanisms are described.

Davis, G. R.; Furniss, I.; Patrick, T. J.; Sidey, R. C.; Towlson, W. A.

1991-01-01

320

Water emission in NGC1333-IRAS4: The physical structure of the envelope  

E-print Network

We report ISO-LWS far infrared observations of CO, water and oxygen lines towards the protobinary system IRAS4 in the NGC1333 cloud. We detected several water, OH, CO rotational lines, and two [OI] and [CII] fine structure lines. Given the relatively poor spectral and spatial resolution of these observations, assessing the origin of the observed emission is not straightforward. In this paper, we focus on the water line emission and explore the hypothesis that it originates in the envelopes that surround the two protostars, IRAS4 A and B, thanks to an accurate model. The model reproduces quite well the observed water line fluxes, predicting a density profile, mass accretion rate, central mass, and water abundance profile in agreement with previous works. We hence conclude that the emission from the envelopes is a viable explanation for the observed water emission, although we cannot totally rule out the alternative that the observed water emission originates in the outflow.

S. Maret; C. Ceccarelli; E. Caux; A. G. G. M. Tielens; A. Castets

2002-09-25

321

Progress Towards the Solar Dynamics Observatory  

NASA Technical Reports Server (NTRS)

The Solar Dynamics Observatory, or SDO, is scheduled to be the first mission to launch in 2007 under the new Living With a Star (LWS) program. It builds on the success of SOHO and other recent solar missions, but will observe the Sun at greater resolution and faster time cadence with a set of remote sensing instruments generating data in excess of 100 megabytes per second. The Science Definition Team produced a report consisting of a series of science objectives and a baseline instrument complement. Instrument proposals were due in April 2002, with selection to occur in the late summer of 2002. The spacecraft is being built at NASA Goddard Spacecraft Center by a team of engineers which are currently undergoing the formulation process. The presentation will discuss the current status of the science investigation selection and the spacecraft formulation.

Thompson, B. J.; Schwer, K. O.; Rabin, Douglas M. (Technical Monitor)

2002-01-01

322

Development of a long wavelength spectrometer for the 24-channel multispectral scanner: Instructions for installation, start-up, and adjustment  

NASA Technical Reports Server (NTRS)

The basic information is presented, which is required for start-up and operation of two long-wavelength focal-plane and cooler assemblies, including the amplifiers and temperature control systems. The focal plane systems, referred to as the long wavelength spectrometer (LWS) were developed for direct replacement of Arrays 3 and 4 into the multispectral scanner presently being operated by the NASA Manned Spacecraft Center Facility, and Laboratory Support Branch. The equipment is comprised of two major sub-assemblies: Array 3 with three indium antimonide detector channels and Array 4 with seven mercury doped Germanium detector channels. Each array is mounted on a cryogenic cooler and includes the vacuum housings, mounting hardware (x, y, z translation and rotation stages) and detector signal conditioning, temperature control and monitoring electronics. The two arrays were designed to operate independently and do not share common equipment (viz power supplies, housings, mounts, etc.).

1974-01-01

323

Spectroscopy of Stellar Jets, Outflows, and Young Stellar Objects with the Infrared Space Observatory  

E-print Network

The Infrared Space Observatory (ISO) was an extremely successful european space mission that gave us an unparallel view of the Universe in the infrared, and provided us with hundreds of observations of star forming regions and bipolar outflows. Three of the instrument teams, in charge of the infrared camera (CAM) and the two spectrometers at short and long wavelengths (SWS and LWS respectively), used a significant fraction of their guarantee time to study YSOs and outflows spectroscopically. In here, I will briefly review some of their main findings, particularly the detection of water, H2 rotational emission lines and the presence of other complex molecules. I will present new spectroscopic results on HH 1-2, HH 7-11 and Cep E, and their sources. And finally, I will discuss some of the general trends derived from these observations and their relevance in understanding the emission from these objects using J and C shock models.

Alberto Noriega-Crespo

2001-01-04

324

MHD modeling of the solar corona: Progress and challenges  

NASA Astrophysics Data System (ADS)

The Sun and its activity is the ultimate driver of space weather at Earth. This influence occurs not only via eruptive phenomena such as coronal mass ejections, but also through the structure of the corona itself, which forms the genesis of fast solar wind streams that trigger recurrent geomagnetic activity. Coronal structure also determines the connection of the ambient interplanetary magnetic field to CME-related shocks and impulsive solar flares, and thus controls where solar energetic particles propagate. In this talk we describe both the present state of the art and new directions in coronal modeling for both dynamic and slowly varying phenomena. We discuss the challenges to incorporating these capabilities into future space weather forecasting and specification models. Supported by NASA through the HTP, LWS, and SR&T programs, by NSF through the FESD and CISM programs, and by the AFOSR Space Science program.

Linker, Jon; Mikic, Zoran; Lionello, Roberto; Riley, Pete; Titov, Viacheslav; Torok, Tibor

2012-07-01

325

Signaling States of Rhodopsin  

PubMed Central

Vertebrate rhodopsin consists of the apoprotein opsin and the chromophore 11-cis-retinal covalently linked via a protonated Schiff base. Upon photoisomerization of the chromophore to all-trans-retinal, the retinylidene linkage hydrolyzes, and all-trans-retinal dissociates from opsin. The pigment is eventually restored by recombining with enzymatically produced 11-cis-retinal. All-trans-retinal release occurs in parallel with decay of the active form, metarhodopsin (Meta) II, in which the original Schiff base is intact but deprotonated. The intermediates formed during Meta II decay include Meta III, with the original Schiff base reprotonated, and Meta III-like pseudo-photoproducts. Using an intrinsic fluorescence assay, Fourier transform infrared spectroscopy, and UV-visible spectroscopy, we investigated Meta II decay in native rod disk membranes. Up to 40% of Meta III is formed without changes in the intrinsic Trp fluorescence and thus without all-trans-retinal release. NADPH, a cofactor for the reduction of all-trans-retinal to all-trans-retinol, does not accelerate Meta II decay nor does it change the amount of Meta III formed. However, Meta III can be photoconverted back to the Meta II signaling state. The data are described by two quasi-irreversible pathways, leading in parallel into Meta III or into release of all-trans-retinal. Therefore, Meta III could be a form of rhodopsin that is storaged away, thus regulating photoreceptor regeneration. PMID:12427735

Heck, Martin; Schädel, Sandra A.; Maretzki, Dieter; Bartl, Franz J.; Ritter, Eglof; Palczewski, Krzysztof; Hofmann, Klaus Peter

2006-01-01

326

Calnexin Improves the Folding Efficiency of Mutant Rhodopsin in the Presence of Pharmacological Chaperone 11-cis-Retinal*  

PubMed Central

The lectin chaperone calnexin (Cnx) is important for quality control of glycoproteins, and the chances of correct folding of a protein increase the longer the protein interacts with Cnx. Mutations in glycoproteins increase their association with Cnx, and these mutant proteins are retained in the endoplasmic reticulum. However, until now, the increased interaction with Cnx was not known to increase the folding of mutant glycoproteins. Because many human diseases result from glycoprotein misfolding, a Cnx-assisted folding of mutant glycoproteins could be beneficial. Mutations of rhodopsin, the glycoprotein pigment of rod photoreceptors, cause misfolding resulting in retinitis pigmentosa. Despite the critical role of Cnx in glycoprotein folding, surprisingly little is known about its interaction with rhodopsin or whether this interaction could be modulated to increase the folding of mutant rhodopsin. Here, we demonstrate that Cnx preferentially associates with misfolded mutant opsins associated with retinitis pigmentosa. Furthermore, the overexpression of Cnx leads to an increased accumulation of misfolded P23H opsin but not the correctly folded protein. Finally, we demonstrate that increased levels of Cnx in the presence of the pharmacological chaperone 11-cis-retinal increase the folding efficiency and result in an increase in correct folding of mutant rhodopsin. These results demonstrate that misfolded rather than correctly folded rhodopsin is a substrate for Cnx and that the interaction between Cnx and mutant, misfolded rhodopsin, can be targeted to increase the yield of folded mutant protein. PMID:19801547

Noorwez, Syed M.; Sama, Reddy Ranjith K.; Kaushal, Shalesh

2009-01-01

327

Differential effects of bFGF on development of the rat retina.  

PubMed

A variety of growth factors can influence the expression of differentiated properties by cell types of the developing retina. One unresolved question has been whether these factors can direct the differentiation pathway of uncommitted precursors or whether they act to help the expression of properties by already committed cells. To address this question we have studied the effects of basic fibroblast growth factor (bFGF) on the differentiation of ganglion cells and rod photoreceptors in explant cultures of embryonic rat retinas. Incubation of retinas in the presence of bFGF accelerated the appearance of differentiated ganglion cells and incubation in the presence of anti-bFGF antibodies delayed the appearance. bFGF had no effect on the appearance of differentiated rod photoreceptors as judged by expression of opsin, although all-trans-retinoic acid did increase the number of cells expressing opsin. bFGF inhibited the formation of rod photoreceptor rosettes suggesting that it does influence some properties of rods or the adjacent Müller glial cells. The results suggest that bFGF can alter the timing of differentiation of retinal ganglion cells but not direct their production from retinal precursors. PMID:8813395

Zhao, S; Barnstable, C J

1996-06-01

328

Evolution of ultraviolet vision in shorebirds (Charadriiformes).  

PubMed

Diurnal birds belong to one of two classes of colour vision. These are distinguished by the maximum absorbance wavelengths of the SWS1 visual pigment sensitive to violet (VS) and ultraviolet (UVS). Shifts between the classes have been rare events during avian evolution. Gulls (Laridae) are the only shorebirds (Charadriiformes) previously reported to have the UVS type of opsin, but too few species have been sampled to infer that gulls are unique among shorebirds or that Laridae is monomorphic for this trait. We have sequenced the SWS1 opsin gene in a broader sample of species. We confirm that cysteine in the key amino acid position 90, characteristic of the UVS class, has been conserved throughout gull evolution but also that the terns Anous minutus, A. tenuirostris and Gygis alba, and the skimmer Rynchops niger carry this trait. Terns, excluding Anous and Gygis, share the VS conferring serine in position 90 with other shorebirds but it is translated from a codon more similar to that found in UVS shorebirds. The most parsimonious interpretation of these findings, based on a molecular gene tree, is a single VS to UVS shift and a subsequent reversal in one lineage. PMID:20015861

Odeen, Anders; Håstad, Olle; Alström, Per

2010-06-23

329

Constitutive phospholipid scramblase activity of a G protein-coupled receptor  

NASA Astrophysics Data System (ADS)

Opsin, the rhodopsin apoprotein, was recently shown to be an ATP-independent flippase (or scramblase) that equilibrates phospholipids across photoreceptor disc membranes in mammalian retina, a process required for disc homoeostasis. Here we show that scrambling is a constitutive activity of rhodopsin, distinct from its light-sensing function. Upon reconstitution into vesicles, discrete conformational states of the protein (rhodopsin, a metarhodopsin II-mimic, and two forms of opsin) facilitated rapid (>10,000 phospholipids per protein per second) scrambling of phospholipid probes. Our results indicate that the large conformational changes involved in converting rhodopsin to metarhodopsin II are not required for scrambling, and that the lipid translocation pathway either lies near the protein surface or involves membrane packing defects in the vicinity of the protein. In addition, we demonstrate that ?2-adrenergic and adenosine A2A receptors scramble lipids, suggesting that rhodopsin-like G protein-coupled receptors may play an unexpected moonlighting role in re-modelling cell membranes.

Goren, Michael A.; Morizumi, Takefumi; Menon, Indu; Joseph, Jeremiah S.; Dittman, Jeremy S.; Cherezov, Vadim; Stevens, Raymond C.; Ernst, Oliver P.; Menon, Anant K.

2014-10-01

330

Color Vision: The “OH-Site” Rule for Seeing Red and Green  

PubMed Central

Eyes gather information and color forms an extremely important component of the information, more so in the case of animals to forage and navigate within their immediate environment. By using the ONIOM (QM/MM) method, we report a comprehensive theoretical analysis of the structure and molecular mechanism of spectral tuning of monkey-red and green-sensitive visual pigments. We show that, interaction of retinal with three hydroxyl-bearing amino acids near the ?-ionone ring part of the retinal in opsin, A164S, F261Y and A269T, increases the electron delocalization, decreases the BLA of the retinal and leads to variation in the wavelength of maximal absorbance in the red- and green-sensitive visual pigments. Based on the analysis, we propose the “OH-site” rule for seeing red and green. This rule is also shown to account for the spectral shifts obtained from hydroxyl-bearing amino acids near the Schiff base in different visual pigments: at site 292 (A292S, A292Y, and A292T) in bovine and at site 111 (Y111) in squid opsins. Therefore, the OH-site rule is shown to be site-specific and not pigment-specific and thus can be used for tracking spectral shifts in any visual pigment. PMID:22663599

Sekharan, Sivakumar; Katayama, Kota; Kandori, Hideki; Morokuma, Keiji

2013-01-01

331

Shining new light on optogenetics  

NASA Astrophysics Data System (ADS)

Since development of optogenetic stimulation paradigm, there has been several attempts to red shift the excitation maximum of the efficient blue-sensitive opsins. While there has been some success at the cost of altered light-activation kinetics, near-infrared optogenetic probe will be ideal for in-depth cell-specific stimulation of excitable cells in an organ. However, single-photon near-infrared optogenetics based stimulation will still limit precise probing and modulation of in-vivo neural circuits. In contrast, by virtue of non-linear nature of ultrafast light-matter interaction, high spatial precision in optogenetic activation can be achieved in addition to inherent cellular specificity and temporal resolution provided by the opsins. Here, we report use of non-linear optogenetics for stimulation of neurons in-vivo in mouse models. Advantage of using non-linear optogenetics for probing neuronal circuitry is discussed. Further, effectiveness of the non-diffracting optogenetic Bessel beam over classical Gaussian beam in a layered mouse-brain geometry is demonstrated using Monte Carlo (MC) simulation. This is corroborated by electrophysiological measurements in in-vivo mouse models. The large propagation distance, characteristics of Bessel beam is better suited for in-depth single as well as two-photon optogenetic stimulation.

Gu, Ling; Dhakal, Kamal; Li, Ting; Mohanty, Samarendra

2012-02-01

332

In vivo Optogenetic Stimulation of the Rodent Central Nervous System.  

PubMed

The ability to probe defined neural circuits in awake, freely-moving animals with cell-type specificity, spatial precision, and high temporal resolution has been a long sought tool for neuroscientists in the systems-level search for the neural circuitry governing complex behavioral states. Optogenetics is a cutting-edge tool that is revolutionizing the field of neuroscience and represents one of the first systematic approaches to enable causal testing regarding the relation between neural signaling events and behavior. By combining optical and genetic approaches, neural signaling can be bi-directionally controlled through expression of light-sensitive ion channels (opsins) in mammalian cells. The current protocol describes delivery of specific wavelengths of light to opsin-expressing cells in deep brain structures of awake, freely-moving rodents for neural circuit modulation. Theoretical principles of light transmission as an experimental consideration are discussed in the context of performing in vivo optogenetic stimulation. The protocol details the design and construction of both simple and complex laser configurations and describes tethering strategies to permit simultaneous stimulation of multiple animals for high-throughput behavioral testing. PMID:25651158

Sidor, Michelle M; Davidson, Thomas J; Tye, Kay M; Warden, Melissa R; Diesseroth, Karl; McClung, Colleen A

2015-01-01

333

Developmental evolution of the insect retina: insights from standardized numbering of homologous photoreceptors.  

PubMed

The canonical number of eight photoreceptors and their arrangement in the ommatidia of insect compound eyes is very conserved. However significant variations exist in selective groups, such as the Lepidoptera and Hymenoptera, which independently evolved additional photoreceptors. For this and historical reasons, heterogeneous labeling conventions have been in use for photoreceptor subtypes, despite developmentally and structurally well-defined homologies. Extending earlier efforts, we introduce a universal photoreceptor subtype classification key that relates to the Drosophila numbering system. Its application is demonstrated in major insect orders, with detailed information on the relationship to previous conventions. We then discuss new insights that result from the improved understanding of photoreceptor subtype homologies. This includes evidence of functionally imposed ground rules of differential opsin expression, the underappreciated role of R8 as ancestral color receptor, the causes and consequences of parallel R7 photoreceptor addition in Hymenoptera and Lepidoptera, and the ancestral subfunctionalization of outer photoreceptors cells, which may be only developmentally recapitulated in Drosophila. We conclude with pointing out the need for opsin expression data from a wider range of insect orders. PMID:21796775

Friedrich, Markus; Wood, Emily J; Wu, Meng

2011-11-15

334

Noncell-autonomous photoreceptor degeneration in a zebrafish model of choroideremia.  

PubMed

Choroideremia is an X-linked hereditary retinal degeneration resulting from mutations in the Rab escort protein-1 (REP1). The Rep1 protein facilitates posttranslational modification of Rab proteins, which regulate intracellular trafficking in the retinal pigment epithelium (RPE) and photoreceptors and are likely involved in the removal of outer segment disk membranes by the RPE. A critical question for potential treatment of choroideremia is whether photoreceptor degeneration results from autonomous defects in opsin transport within the photoreceptor or as a nonautonomous and secondary consequence of RPE degeneration. To address this question, we have characterized the retinal pathology in zebrafish rep1 mutants, which carry a recessive nonsense mutation in the REP1 gene. Zebrafish rep1 mutants exhibit degeneration of the RPE and photoreceptors and complete loss of visual function as measured by electroretinograms. In the mutant RPE, photoreceptor outer segment material was not effectively eliminated, and large vacuoles were observed. However, opsin trafficking in photoreceptors occurred normally. Mosaic analysis revealed that photoreceptor degeneration was nonautonomous and required contact with the mutant RPE as mutant photoreceptors were rescued in wild-type hosts and wild-type photoreceptors degenerated in mutant hosts. We conclude that mutations in REP1 disrupt cellular processes in the RPE, which causes photoreceptor death as a secondary consequence. These results suggest that therapies that correct the RPE may successfully rescue photoreceptor loss in choroideremia. PMID:17360570

Krock, Bryan L; Bilotta, Joseph; Perkins, Brian D

2007-03-13

335

Incorporation of squalene into rod outer segments  

SciTech Connect

We have reported previously that squalene is the major radiolabeled nonsaponifiable lipid product derived from ({sup 3}H)acetate in short term incubations of frog retinas. In the present study, we demonstrate that newly synthesized squalene is incorporated into rod outer segments under similar in vitro conditions. We show further that squalene is an endogenous constituent of frog rod outer segment membranes; its concentration is approximately 9.5 nmol/mumol of phospholipid or about 9% of the level of cholesterol. Pulse-chase experiments with radiolabeled precursors revealed no metabolism of outer segment squalene to sterols in up to 20 h of chase. Taken together with our previous absolute rate studies, these results suggest that most, if not all, of the squalene synthesized by the frog retina is transported to rod outer segments. Synthesis of protein is not required for squalene transport since puromycin had no effect on squalene incorporation into outer segments. Conversely, inhibition of isoprenoid synthesis with mevinolin had no effect on the incorporation of opsin into the outer segment. These latter results support the conclusion that the de novo synthesis and subsequent intracellular trafficking of opsin and isoprenoid lipids destined for the outer segment occur via independent mechanisms.

Keller, R.K.; Fliesler, S.J. (Univ. of South Florida College of Medicine, Tampa (USA))

1990-08-15

336

Multiple shifts between violet and ultraviolet vision in a family of passerine birds with associated changes in plumage coloration.  

PubMed

Colour vision in diurnal birds falls into two discrete classes, signified by the spectral sensitivity of the violet- (VS) or ultraviolet-sensitive (UVS) short wavelength-sensitive type 1 (SWS1) single cone. Shifts between sensitivity classes are rare; three or four are believed to have happened in the course of avian evolution, one forming UVS higher passerines. Such shifts probably affect the expression of shortwave-dominated plumage signals. We have used genomic DNA sequencing to determine VS or UVS affinity in fairy-wrens and allies, Maluridae, a large passerine family basal to the known UVS taxa. We have also spectrophotometrically analysed male plumage coloration as perceived by the VS and UVS vision systems. Contrary to any other investigated avian genus, Malurus (fairy-wrens) contains species with amino acid residues typical of either VS or UVS cone opsins. Three bowerbird species (Ptilonorhynchidae) sequenced for outgroup comparison carry VS opsin genes. Phylogenetic reconstructions render one UVS gain followed by one or more losses as the most plausible evolutionary scenario. The evolution of avian ultraviolet sensitivity is hence more complex, as a single shift no longer explains its distribution in Passeriformes. Character correlation analysis proposes that UVS vision is associated with shortwave-reflecting plumage, which is widespread in Maluridae. PMID:21976683

Odeen, Anders; Pruett-Jones, Stephen; Driskell, Amy C; Armenta, Jessica K; Håstad, Olle

2012-04-01

337

Photoreceptor types and distributions in the retinae of insectivores.  

PubMed

The retinae of insectivores have been rarely studied, and their photoreceptor arrangements and expression patterns of visual pigments are largely unknown. We have determined the presence and distribution of cones in three species of shrews (common shrew Sorex araneus, greater white-toothed shrew Crocidura russula, dark forest shrew Crocidura poensis; Soricidae) and in the lesser hedgehog tenrec Echinops telfairi (Tenrecidae). Special cone types were identified and quantified in flattened whole retinae by antisera/antibodies recognizing the middle-to-long-wavelength-sensitive (M/L-)cone opsin and the short-wavelength-sensitive (S-)cone opsin, respectively. A combination of immunocytochemistry with conventional histology was used to assess rod densities and cone/rod ratios. In all four species the rods dominate at densities of about 230,000-260,000/mm2. M/L- and S-cones are present, comprising between 2% of the photoreceptors in the nocturnal Echinops telfairi and 13% in Sorex araneus that has equal diurnal and nocturnal activity phases. This suggests dichromatic color vision like in many other mammals. A striking feature in all four species are dramatically higher S-cone proportions in ventral than in dorsal retina (0.5% vs. 2.5-12% in Sorex, 5-15% vs. 30-45% in Crocidura poensis, 3-12% vs. 20-50% in Crocidura russula, 10-30% vs. 40-70% in Echinops). The functional and comparative aspects of these structural findings are discussed. PMID:11193110

Peichl, L; Künzle, H; Vogel, P

2000-01-01

338

Diverse types of ganglion cell photoreceptors in the mammalian retina.  

PubMed

Photoreceptors carry out the first step in vision by capturing light and transducing it into electrical signals. Rod and cone photoreceptors efficiently translate photon capture into electrical signals by light activation of opsin-type photopigments. Until recently, the central dogma was that, for mammals, all phototransduction occurred in rods and cones. However, the recent discovery of a novel photoreceptor type in the inner retina has fundamentally challenged this view. These retinal ganglion cells are intrinsically photosensitive and mediate a broad range of physiological responses such as photoentrainment of the circadian clock, light regulation of sleep, pupillary light reflex, and light suppression of melatonin secretion. Intrinsically photosensitive retinal ganglion cells express melanopsin, a novel opsin-based signaling mechanism reminiscent of that found in invertebrate rhabdomeric photoreceptors. Melanopsin-expressing retinal ganglion cells convey environmental irradiance information directly to brain centers such as the hypothalamus, preoptic nucleus, and lateral geniculate nucleus. Initial studies suggested that these melanopsin-expressing photoreceptors were an anatomically and functionally homogeneous population. However, over the past decade or so, it has become apparent that these photoreceptors are distinguishable as individual subtypes on the basis of their morphology, molecular markers, functional properties, and efferent projections. These results have provided a novel classification scheme with five melanopsin photoreceptor subtypes in the mammalian retina, each presumably with differential input and output properties. In this review, we summarize the evidence for the structural and functional diversity of melanopsin photoreceptor subtypes and current controversies in the field. PMID:22480975

Sand, Andrea; Schmidt, Tiffany M; Kofuji, Paulo

2012-07-01

339

Isolation and characterization of melanopsin and pinopsin expression within photoreceptive sites of reptiles  

NASA Astrophysics Data System (ADS)

Non-mammalian vertebrates have multiple extraocular photoreceptors, mainly localised in the pineal complex and the brain, to mediate irradiance detection. In this study, we report the full-length cDNA cloning of ruin lizard melanopsin and pinopsin. The high level of identity with opsins in both the transmembrane regions, where the chromophore binding site is located, and the intracellular loops, where the G-proteins interact, suggests that both melanopsin and pinopsin should be able to generate a stable photopigment, capable of triggering a transduction cascade mediated by G-proteins. Phylogenetic analysis showed that both opsins are located on the expected branches of the corresponding sequences of ortholog proteins. Subsequently, using RT-PCR and RPA analysis, we verified the expression of ruin lizard melanopsin and pinopsin in directly photosensitive organs, such as the lateral eye, brain, pineal gland and parietal eye. Melanopsin expression was detected in the lateral eye and all major regions of the brain. However, different from the situation in Xenopus and chicken, melanopsin is not expressed in the ruin lizard pineal. Pinopsin mRNA expression was only detected in the pineal complex. As a result of their phylogenetic position and ecology, reptiles provide the circadian field with some of the most interesting models for understanding the evolution of the vertebrate circadian timing system and its response to light. This characterization of melanopsin and pinopsin expression in the ruin lizard will be important for future studies aimed at understanding the molecular basis of circadian light detection in reptiles.

Frigato, Elena; Vallone, Daniela; Bertolucci, Cristiano; Foulkes, Nicholas S.

2006-08-01

340

Archaebacterial rhodopsin sequences: Implications for evolution  

NASA Technical Reports Server (NTRS)

It was proposed over 10 years ago that the archaebacteria represent a separate kingdom which diverged very early from the eubacteria and eukaryotes. It follows that investigations of archaebacterial characteristics might reveal features of early evolution. So far, two genes, one for bacteriorhodopsin and another for halorhodopsin, both from Halobacterium halobium, have been sequenced. We cloned and sequenced the gene coding for the polypeptide of another one of these rhodopsins, a halorhodopsin in Natronobacterium pharaonis. Peptide sequencing of cyanogen bromide fragments, and immuno-reactions of the protein and synthetic peptides derived from the C-terminal gene sequence, confirmed that the open reading frame was the structural gene for the pharaonis halorhodopsin polypeptide. The flanking DNA sequences of this gene, as well as those of other bacterial rhodopsins, were compared to previously proposed archaebacterial consensus sequences. In pairwise comparisons of the open reading frame with DNA sequences for bacterio-opsin and halo-opsin from Halobacterium halobium, silent divergences were calculated. These indicate very considerable evolutionary distance between each pair of genes, even in the dame organism. In spite of this, three protein sequences show extensive similarities, indicating strong selective pressures.

Lanyi, J. K.

1991-01-01

341

A maximum-likelihood analysis of eight phylogenetic markers in gallwasps (Hymenoptera: Cynipidae): implications for insect phylogenetic studies.  

PubMed

We assessed the utility of eight DNA sequence markers (5.8S rDNA, 18S rDNA, 28S rDNA, ITS regions, long-wavelength opsin, elongation factor 1-alpha, cytochrome b, and cytochrome oxidase I) in reconstructing phylogenetic relationships at various levels of divergence in gallwasps (Hymenoptera: Cynipidae), using a set of eight exemplar taxa. We report sequence divergence values and saturation levels and compare phylogenetic results of these sequences analyzed both separately and combined to a well-corroborated morphological phylogeny. Likelihood ratio tests were used to find the best evolutionary model fitting each of the markers. The likelihood model best explaining the data is, for most loci, parameter rich, with strong A-T bias for mitochondrial loci and strong rate heterogeneity for the majority of loci. Our data suggest that 28S rDNA, elongation factor 1-alpha, and long-wavelength opsin may be potentially useful markers for the resolution of cynipid and other insect within-family-level divergences (circa 50-100 mya old), whereas mitochondrial loci and ITS regions are most useful for lower-level phylogenetics. In contrast, the 18S rDNA marker is likely to be useful for the resolution of above-family-level relationships. PMID:11820842

Rokas, Antonis; Nylander, Johan A A; Ronquist, Fredrik; Stone, Graham N

2002-02-01

342

The molecular genetics of red and green color vision in mammals.  

PubMed

To elucidate the molecular mechanisms of red-green color vision in mammals, we have cloned and sequenced the red and green opsin cDNAs of cat (Felis catus), horse (Equus caballus), gray squirrel (Sciurus carolinensis), white-tailed deer (Odocoileus virginianus), and guinea pig (Cavia porcellus). These opsins were expressed in COS1 cells and reconstituted with 11-cis-retinal. The purified visual pigments of the cat, horse, squirrel, deer, and guinea pig have lambdamax values at 553, 545, 532, 531, and 516 nm, respectively, which are precise to within +/-1 nm. We also regenerated the "true" red pigment of goldfish (Carassius auratus), which has a lambdamax value at 559 +/- 4 nm. Multiple linear regression analyses show that S180A, H197Y, Y277F, T285A, and A308S shift the lambdamax values of the red and green pigments in mammals toward blue by 7, 28, 7, 15, and 16 nm, respectively, and the reverse amino acid changes toward red by the same extents. The additive effects of these amino acid changes fully explain the red-green color vision in a wide range of mammalian species, goldfish, American chameleon (Anolis carolinensis), and pigeon (Columba livia). PMID:10511567

Yokoyama, S; Radlwimmer, F B

1999-10-01

343

Euphausiid visual pigments. The rhodopsins of Euphausia superba and Meganyctiphanes norvegica (Crustacea, Euphausiacea)  

PubMed Central

The rhabdoms of Euphausia superba contain one digitonin-extractable rhodopsin, lambda max 485 nm. The rhodopsin undergoes unusual pH- dependent spectral changes: above neutrality, the absorbance decreases progressively at 485 nm and rises near 370 nm. This change is reversible and appears to reflect an equilibrium between a protonated and an unprotonated form of the rhodopsin Schiff-base linkage. Near neutral pH and at 10 degrees C, the rhodopsin is partiaLly converted by 420-nm light to a stable 493-nm metarhodopsin. The metarhodopsin is partially photoconverted to rhodopsin by long-wavelength light in the absence of NH2OH; in the presence of NH2OH, it is slowly converted to retinal oxime and opsin. The rhodopsin of Meganyctiphanes norvegica measured in fresh rhabdoms by microspectrophotometry has properties very similar to those of the extracted rhodopsin of E. superba. Its lambda max is 488 nm and it is partially photoconverted by short wavelength irradiation to a stable photoconvertible metarhodopsin similar to that of E. superba. In the presence of light and NH2OH, the M. norvegica metarhodopsin is converted to retinal oxime and opsin. Our results indicate that previous determinations of euphausiid rhodopsin absorbance spectra were incorrect because of accessory pigment contamination. PMID:7142953

1982-01-01

344

The amphioxus genome illuminates vertebrate origins and cephalochordate biology  

PubMed Central

Cephalochordates, urochordates, and vertebrates evolved from a common ancestor over 520 million years ago. To improve our understanding of chordate evolution and the origin of vertebrates, we intensively searched for particular genes, gene families, and conserved noncoding elements in the sequenced genome of the cephalochordate Branchiostoma floridae, commonly called amphioxus or lancelets. Special attention was given to homeobox genes, opsin genes, genes involved in neural crest development, nuclear receptor genes, genes encoding components of the endocrine and immune systems, and conserved cis-regulatory enhancers. The amphioxus genome contains a basic set of chordate genes involved in development and cell signaling, including a fifteenth Hox gene. This set includes many genes that were co-opted in vertebrates for new roles in neural crest development and adaptive immunity. However, where amphioxus has a single gene, vertebrates often have two, three, or four paralogs derived from two whole-genome duplication events. In addition, several transcriptional enhancers are conserved between amphioxus and vertebrates—a very wide phylogenetic distance. In contrast, urochordate genomes have lost many genes, including a diversity of homeobox families and genes involved in steroid hormone function. The amphioxus genome also exhibits derived features, including duplications of opsins and genes proposed to function in innate immunity and endocrine systems. Our results indicate that the amphioxus genome is elemental to an understanding of the biology and evolution of nonchordate deuterostomes, invertebrate chordates, and vertebrates. PMID:18562680

Holland, Linda Z.; Albalat, Ricard; Azumi, Kaoru; Benito-Gutiérrez, Èlia; Blow, Matthew J.; Bronner-Fraser, Marianne; Brunet, Frederic; Butts, Thomas; Candiani, Simona; Dishaw, Larry J.; Ferrier, David E.K.; Garcia-Fernàndez, Jordi; Gibson-Brown, Jeremy J.; Gissi, Carmela; Godzik, Adam; Hallböök, Finn; Hirose, Dan; Hosomichi, Kazuyoshi; Ikuta, Tetsuro; Inoko, Hidetoshi; Kasahara, Masanori; Kasamatsu, Jun; Kawashima, Takeshi; Kimura, Ayuko; Kobayashi, Masaaki; Kozmik, Zbynek; Kubokawa, Kaoru; Laudet, Vincent; Litman, Gary W.; McHardy, Alice C.; Meulemans, Daniel; Nonaka, Masaru; Olinski, Robert P.; Pancer, Zeev; Pennacchio, Len A.; Pestarino, Mario; Rast, Jonathan P.; Rigoutsos, Isidore; Robinson-Rechavi, Marc; Roch, Graeme; Saiga, Hidetoshi; Sasakura, Yasunori; Satake, Masanobu; Satou, Yutaka; Schubert, Michael; Sherwood, Nancy; Shiina, Takashi; Takatori, Naohito; Tello, Javier; Vopalensky, Pavel; Wada, Shuichi; Xu, Anlong; Ye, Yuzhen; Yoshida, Keita; Yoshizaki, Fumiko; Yu, Jr-Kai; Zhang, Qing; Zmasek, Christian M.; de Jong, Pieter J.; Osoegawa, Kazutoyo; Putnam, Nicholas H.; Rokhsar, Daniel S.; Satoh, Noriyuki; Holland, Peter W.H.

2008-01-01

345

Identification and functional analysis of the vision-specific BBS3 (ARL6) long isoform.  

PubMed

Bardet-Biedl Syndrome (BBS) is a heterogeneous syndromic form of retinal degeneration. We have identified a novel transcript of a known BBS gene, BBS3 (ARL6), which includes an additional exon. This transcript, BBS3L, is evolutionally conserved and is expressed predominantly in the eye, suggesting a specialized role in vision. Using antisense oligonucleotide knockdown in zebrafish, we previously demonstrated that bbs3 knockdown results in the cardinal features of BBS in zebrafish, including defects to the ciliated Kupffer's Vesicle and delayed retrograde melanosome transport. Unlike bbs3, knockdown of bbs3L does not result in Kupffer's Vesicle or melanosome transport defects, rather its knockdown leads to impaired visual function and mislocalization of the photopigment green cone opsin. Moreover, BBS3L RNA, but not BBS3 RNA, is sufficient to rescue both the vision defect as well as green opsin localization in the zebrafish retina. In order to demonstrate a role for Bbs3L function in the mammalian eye, we generated a Bbs3L-null mouse that presents with disruption of the normal photoreceptor architecture. Bbs3L-null mice lack key features of previously published Bbs-null mice, including obesity. These data demonstrate that the BBS3L transcript is required for proper retinal function and organization. PMID:20333246

Pretorius, Pamela R; Baye, Lisa M; Nishimura, Darryl Y; Searby, Charles C; Bugge, Kevin; Yang, Baoli; Mullins, Robert F; Stone, Edwin M; Sheffield, Val C; Slusarski, Diane C

2010-03-01

346

Identification and Functional Analysis of the Vision-Specific BBS3 (ARL6) Long Isoform  

PubMed Central

Bardet-Biedl Syndrome (BBS) is a heterogeneous syndromic form of retinal degeneration. We have identified a novel transcript of a known BBS gene, BBS3 (ARL6), which includes an additional exon. This transcript, BBS3L, is evolutionally conserved and is expressed predominantly in the eye, suggesting a specialized role in vision. Using antisense oligonucleotide knockdown in zebrafish, we previously demonstrated that bbs3 knockdown results in the cardinal features of BBS in zebrafish, including defects to the ciliated Kupffer's Vesicle and delayed retrograde melanosome transport. Unlike bbs3, knockdown of bbs3L does not result in Kupffer's Vesicle or melanosome transport defects, rather its knockdown leads to impaired visual function and mislocalization of the photopigment green cone opsin. Moreover, BBS3L RNA, but not BBS3 RNA, is sufficient to rescue both the vision defect as well as green opsin localization in the zebrafish retina. In order to demonstrate a role for Bbs3L function in the mammalian eye, we generated a Bbs3L-null mouse that presents with disruption of the normal photoreceptor architecture. Bbs3L-null mice lack key features of previously published Bbs-null mice, including obesity. These data demonstrate that the BBS3L transcript is required for proper retinal function and organization. PMID:20333246

Pretorius, Pamela R.; Baye, Lisa M.; Nishimura, Darryl Y.; Searby, Charles C.; Bugge, Kevin; Yang, Baoli; Mullins, Robert F.; Stone, Edwin M.; Sheffield, Val C.; Slusarski, Diane C.

2010-01-01

347

Orientation of Intermediates in the Bleaching of Shear-Oriented Rhodopsin  

PubMed Central

Cattle rhodopsin can be highly oriented by shearing a wet paste of digitonin micelles of this visual pigment between two quartz slides. This orients the rhodopsin micelles so that their chromophores lie mainly parallel to the direction of shear. In such preparations the orientation of rhodopsin and intermediates of its bleaching by light have been measured with plane-polarized light from -195°C to room temperature. The chromophore maintains essentially the same orientation as in rhodopsin in all the intermediates of bleaching: bathorhodopsin (prelumirhodopsin), lumirhodopsin, and metarhodopsins I and II. When, however, the retinaldehyde chromophore is hydrolyzed from opsin in the presence of hydroxylamine, the retinaldehyde oxime that results rotates so as to lie mainly across the direction of shear. That is, the retinal oxime, though free, orients itself upon the oriented matrix of the opsin-digitonin micelles. These experiments show the rhodopsin-digitonin micelle to be markedly asymmetric, with the chromophore lying parallel to its long axis. The asymmetry could originate in the formation of the micelle, in rhodopsin itself, or by its linear polymerization under the conditions of the experiment. If rhodopsin itself is markedly asymmetric, for which there is some evidence, then, since in the rod outer segments its chromophores lie parallel to the disk membranes, the molecules themselves must lie with their long axes parallel to the membranes. PMID:4751384

Wright, Woodring E.; Brown, Paul K.; Wald, George

1973-01-01

348

Glutamic acid-113 serves as the retinylidene Schiff base counterion in bovine rhodopsin.  

PubMed Central

The characteristic wavelength at which a visual pigment absorbs light is regulated by interactions between protein (opsin) and retinylidene Schiff base chromophore. By using site-directed mutagenesis, charged amino acids in bovine rhodopsin transmembrane helix C were systematically replaced. Substitution of glutamic acid-134 or arginine-135 did not affect spectral properties. However, substitution of glutamic acid-122 by glutamine or by aspartic acid formed pigments that were blue-shifted in light absorption (lambda max = 480 nm and 475 nm, respectively). While the substitution of glutamic acid-113 by aspartic acid gave a slightly red-shifted pigment (lambda max = 505 nm), replacement by glutamine formed a pigment that was strikingly blue-shifted in light absorption (lambda max = 380 nm). The 380-nm species existed in a pH-dependent equilibrium with a 490-nm species such that at acidic pH all of the pigment was converted to lambda max = 490 nm. We conclude that glutamic acid-113 serves as the retinylidene Schiff base counterion in rhodopsin. We believe that this opsin-chromophore interaction is an example of a general mechanism of color regulation in the visual pigments. PMID:2573063

Sakmar, T P; Franke, R R; Khorana, H G

1989-01-01

349

Spectral heterogeneity of honeybee ommatidia  

NASA Astrophysics Data System (ADS)

The honeybee compound eye is equipped with ultraviolet, blue, and green receptors, which form the physiological basis of a trichromatic color vision system. We studied the distribution of the spectral receptors by localizing the three mRNAs encoding the opsins of the ultraviolet-, blue- and green-absorbing visual pigments. The expression patterns of the three opsin mRNAs demonstrated that three distinct types ommatidia exist, refuting the common assumption that the ommatidia composing the bee compound eye contain identical sets of spectral receptors. We found that type I ommatidia contain one ultraviolet and one blue receptor, type II ommatidia contain two ultraviolet receptors, and type III ommatidia have two blue receptors. All the three ommatidial types contain six green receptors. The ommatidia appear to be distributed rather randomly over the retina. The ratio of type I, II, and III ommatidia was about 44:46:10. Type III ommatidia appeared to be slightly more frequent (18%) in the anterior part of the ventral region of the eye. Retinal heterogeneity and ommatidial randomness, first clearly demonstrated in butterflies, seems to be a common design principle of the eyes of insects.

Wakakuwa, Motohiro; Kurasawa, Masumi; Giurfa, Martin; Arikawa, Kentaro

2005-10-01

350

Multiple shifts between violet and ultraviolet vision in a family of passerine birds with associated changes in plumage coloration  

PubMed Central

Colour vision in diurnal birds falls into two discrete classes, signified by the spectral sensitivity of the violet- (VS) or ultraviolet-sensitive (UVS) short wavelength-sensitive type 1 (SWS1) single cone. Shifts between sensitivity classes are rare; three or four are believed to have happened in the course of avian evolution, one forming UVS higher passerines. Such shifts probably affect the expression of shortwave-dominated plumage signals. We have used genomic DNA sequencing to determine VS or UVS affinity in fairy-wrens and allies, Maluridae, a large passerine family basal to the known UVS taxa. We have also spectrophotometrically analysed male plumage coloration as perceived by the VS and UVS vision systems. Contrary to any other investigated avian genus, Malurus (fairy-wrens) contains species with amino acid residues typical of either VS or UVS cone opsins. Three bowerbird species (Ptilonorhynchidae) sequenced for outgroup comparison carry VS opsin genes. Phylogenetic reconstructions render one UVS gain followed by one or more losses as the most plausible evolutionary scenario. The evolution of avian ultraviolet sensitivity is hence more complex, as a single shift no longer explains its distribution in Passeriformes. Character correlation analysis proposes that UVS vision is associated with shortwave-reflecting plumage, which is widespread in Maluridae. PMID:21976683

Ödeen, Anders; Pruett-Jones, Stephen; Driskell, Amy C.; Armenta, Jessica K.; Håstad, Olle

2012-01-01

351

Cone pigments in a North American marsupial, the opossum (Didelphis virginiana).  

PubMed

Only two of the four cone opsin gene families found in vertebrates are represented in contemporary eutherian and marsupial species. Recent genetic studies of two species of South American marsupial detected the presence of representatives from two of the classes of cone opsin genes and the structures of these genes predicted cone pigments with respective peaks in the ultraviolet and long-wavelength portions of the spectrum. The Virginia opossum (Didelphis virginiana), a profoundly nocturnal animal, is the only marsupial species found in North America. The prospects for cone-based vision in this species were examined through recordings of the electroretinogram (ERG), a commonly examined retinal response to photic stimulation. Recorded under flickering-light conditions that elicit signals from cone photoreceptors, the spectral sensitivity of the opossum eye is well accounted for by contributions from the presence of a single cone pigment having peak absorption at 561-562 nm. A series of additional experiments that employed various chromatic adaptation paradigms were conducted in a search for possible contributions from a second (short-wavelength sensitive) cone pigment. We found no evidence that such a mechanism contributes to the ERG in this marsupial. PMID:20224889

Jacobs, Gerald H; Williams, Gary A

2010-05-01

352

Development of transgenic animals for optogenetic manipulation of mammalian nervous system function: Progress and prospects for behavioral neuroscience  

PubMed Central

Here we review the rapidly growing toolbox of transgenic mice and rats that exhibit functional expression of engineered opsins for neuronal activation and silencing with light. Collectively, these transgenic animals are enabling neuroscientists to access and manipulate the many diverse cell types in the mammalian nervous system in order to probe synaptic and circuitry connectivity, function, and dysfunction. The availability of transgenic lines affords important advantages such as stable and heritable transgene expression patterns across experimental cohorts. As such, the use of transgenic lines precludes the need for other costly and labor-intensive procedures to achieve functional transgene expression in each individual experimental animal. This represents an important consideration when large cohorts of experimental animals are desirable as in many common behavioral assays. We describe the diverse strategies that have been implemented for developing transgenic mouse and rat lines and highlight recent advances that have led to dramatic improvements in achieving functional transgene expression of engineered opsins. Furthermore, we discuss considerations and caveats associated with implementing recently developed transgenic lines for optogenetics-based experimentation. Lastly, we propose strategies that can be implemented to develop and refine the next generation of genetically modified animals for behaviorally-focused optogenetics-based applications. PMID:23473879

Ting, Jonathan T.; Feng, Guoping

2014-01-01

353

Novel approach to test the relative recovery of liquid-phase standard in sorbent-tube analysis of gaseous volatile organic compounds.  

PubMed

Sorbent tubes (STs) are highly efficient and versatile tools for collecting gaseous samples of volatile organic compounds (VOCs). In order to assess the experimental bias in their application, the relative recovery (RR) of 19 VOCs (acetaldehyde, propionaldehyde, butyraldehyde, isovaleraldehyde, valeraldehyde, benzene, toluene, m-xylene, p-xylene, o-xylene, styrene, methyl ethyl ketone, methyl isobutyl ketone, isobutyl alcohol, butyl acetate, propionic acid, butyric acid, isovaleric acid, and n-valeric acid) was evaluated in accordance to three different sorbent tube types: (1) Tenax (Te), (2) Carbopack X (X), and (3) Tenax + Carbopack B + Carboxen 1000 (TBC). Calibration was initially made by direct injection of the liquid working standard (L-WS) into the link tube (LT) of the thermal desorption (TD) system. The LT was modified to optimize the transfer of all the VOCs to the focusing trap of the TD. Three different types of ST were then loaded with the same L-WS using (1) direct injection (DI) to tube and (2) injection to tube via vaporization (VAP). The results of the two ST/TD methods (DI and VAP) were normalized to those of the LT/TD to derive RR. The mean RR values of all target VOCs were 62.6 (X), 83.9 (Te), and 82.8% (TBC) for the DI and 76.5, 75.8, and 81.0% for the VAP. Although the results using TBC and Te tubes exhibited better recovery in DI than in VAP, those of X tubes had the reverse trend. As such, the relative affinity of each sorbent material can be affected by the mode of introduction of the standard. The practicality of the LT/TD, especially as a reference for the ST/TD, was also validated from some environmental samples in an ancillary experiment. As such, we were able to demonstrate the usefulness of the LT/TD method to evaluate analyte recovery from spiked sorbent tubes. PMID:22468653

Kim, Yong-Hyun; Kim, Ki-Hyun

2012-05-01

354

Producing acoustic 'Frozen Waves': simulated experiments with diffraction/attenuation resistant beams in lossy media.  

PubMed

The so-called Localized Waves (LW), and the "Frozen Waves" (FW), have raised significant attention in the areas of Optics and Ultrasound, because of their surprising energy localization properties. The LWs resist the effects of diffraction for large distances, and possess an interesting self-reconstruction -self-healing- property (after obstacles with size smaller than the antenna's); while the FWs, a sub-class of LWs, offer the possibility of arbitrarily modeling the longitudinal field intensity pattern inside a prefixed interval, for instance 0?z?L, of the wave propagation axis. More specifically, the FWs are localized fields "at rest", that is, with a static envelope (within which only the carrier wave propagates), and can be endowed moreover with a high transverse localization. In this paper we investigate, by simulated experiments, various cases of generation of ultrasonic FW fields, with the frequency of f0=1 MHz in a water-like medium, taking account of the effects of attenuation. We present results of FWs for distances up to L=80 mm, in attenuating media with absorption coefficient ? in the range 70???170 dB/m. Such simulated FW fields are constructed by using a procedure developed by us, via appropriate finite superpositions of monochromatic ultrasonic Bessel beams. We pay due attention to the selection of the FW parameters, constrained by the rather tight restrictions imposed by experimental Acoustics, as well as to some practical implications of the transducer design. The energy localization properties of the Frozen Waves can find application even in many medical apparatus, such as bistouries or acoustic tweezers, as well as for treatment of diseased tissues (in particular, for the destruction of tumor cells, without affecting the surrounding tissues; also for kidney stone shuttering, etc.). PMID:24709072

Prego-Borges, José L; Zamboni-Rached, Michel; Recami, Erasmo; Costa, Eduardo Tavares

2014-08-01

355

Living with a Star: New Opportunities in Sun-Climate Research  

NASA Technical Reports Server (NTRS)

Living With a Star is a NASA initiative employing the combination of dedicated spacecraft with targeted research and modeling efforts to improve what we know of solar effects of all kinds on the Earth and its surrounding space environment, with particular emphasis on those that have significant practical impacts on life and society. The highest priority among these concerns is the subject of this report: the potential effects of solar variability on regional and global climate, including the extent to which solar variability has contributed to the well-documented warming of the Earth in the last 100 years. Understanding how the climate system reacts to external forcing from the Sun will also greatly improve our knowledge of how climate will respond to other climate drivers, including those of anthropogenic origin. A parallel element of the LWS program addresses solar effects on space weather : the impulsive emissions of charged particles, short-wave electromagnetic radiation and magnetic disturbances in the upper atmosphere and near-Earth environment that also affect life and society. These include a wide variety of solar impacts on aeronautics, astronautics, electric power transmission, and national defense. Specific examples are (1) the impacts of potentially- damaging high energy radiation and atomic particles of solar origin on satellites and satellite operations, spacecraft electronics systems and components, electronic communications, electric power distribution grids, navigational and GPS systems, and high altitude aircraft; and (2) the threat of sporadic, high-energy solar radiation to astronauts and high altitude aircraft passengers and crews. Elements of the LWS program include an array of dedicated spacecraft in near- Earth and near-Sun orbits that will closely study and observe both the Sun itself and the impacts of its variations on the Earth's radiation belts and magnetosphere, the upper atmosphere, and ionosphere. These spacecraft, positioned to study and monitor changing conditions in the Sun-Earth neighborhood, will also serve as sentinels of solar storms and impulsive events.

2003-01-01

356

Engineering development of a lightweight high-pressure scarifier for tank waste retrieval  

SciTech Connect

The Retrieval Process Development and Enhancements Program (RPD&E) is sponsored by the U.S. Department of Energy Tanks Focus Area to investigate existing and emerging retrieval processes suitable for the retrieval of high-level radioactive waste inside underground storage tanks. This program, represented by industry, national laboratories, and academia, seeks to provide a technical and cost basis to support site-remediation decisions. Part of this program has involved the development of a high-pressure waterjet dislodging system and pneumatic conveyance integrated as a scarifier. Industry has used high-pressure waterjet technology for many years to mine, cut, clean, and scarify materials with a broad range of properties. The scarifier was developed as an alternate means of retrieving waste inside Hanford single-shell tanks, particularly hard, stubborn waste. Testing of the scarifier has verified its ability to retrieve a wide range of tank waste ranging from extremely hard waste that is resistant to other dislodging means to soft sludge and even supernatant fluid. Since the scarifier expends water at a low rate and recovers most of the water as it is used, the scarifier is well suited for retrieval of tanks that leak and cannot be safely sluiced or applications where significant waste dilution is not acceptable. Although the original scarifier was effective, it became evident that a lighter, more compact version that would be compatible with light weight deployment systems under development, such as the Light Duty Utility Arm, was needed. At the end of FY 95, the Light Weight Scarifier (LWS) was designed to incorporate the features of the original scarifier in a smaller, lighter end effector. During FY 96, the detailed design of the LWS was completed and two prototypes were fabricated.

Hatchell, B.K.

1997-09-01

357

Solar Cycle Variation and Multipoint Studies of ICME Properties  

NASA Technical Reports Server (NTRS)

The goal of the Living With a Star program is to understand the Sun-Earth connection sufficiently well that we can solve problems critical to life and society. This can most effectively be done in the short term using observations from our past and on-going programs. Not only can this approach solve some of the pressing issues but also it can provide ideas for the deployment of future spacecraft in the LWS program. The proposed effort uses data from NEAR, SOHO, Wind, ACE and Pioneer Venus in quadrature, multipoint, and solar cycle studies to study the interplanetary coronal mass ejection and its role in the magnetic flux cycle of the Sun. ICMEs are most important to the LWS objectives because the solar wind conditions associated with these structures are the most geoeffective of any solar wind phenomena. Their ability to produce strong geomagnetic disturbances arises first because of their high speed. This high speed overtakes the ambient solar wind producing a bow shock wave similar to the terrestrial bow shock. In the new techniques we develop as part of this effort we exploit this feature of ICMEs. This shocked plasma has a greater velocity, higher density and stronger magnetic field than the ambient solar wind, conditions that can enhance geomagnetic activity. The driving ICME is a large magnetic structure expanding outward in the solar wind [Gosling, 19961. The ICMEs magnetic field is generally much higher than that in the ambient solar wind and the velocity is high. The twisted nature of the magnetic field in an ICME almost ensures that sometime during the ICME conditions favorable for geomagnetic storm initiation will occur.

Russell, C. T.

2005-01-01

358

ISO-SWS observations of pure rotational water absorption lines toward Orion-IRc2  

E-print Network

First detections of thermal water vapor absorption lines have been made toward Orion IRc2 using the Short Wavelength Spectrometer (SWS) on board the Infrared Space Observatory (ISO). Grating spectra covering wavelengths 25-45 micron yield 19 pure rotational lines, originating from energy levels 200-750 K above ground. Fabry-Perot spectra of 5 transitions resolve the line profiles and reveal the water gas kinematics. The fact that all lines are seen in absorption is in striking contrast with data from the ISO Long Wavelength Spectrometer (LWS), where the water lines appear in emission. At least one line displays a P-Cygni type profile, which suggests that the water is located in an expanding shell centered on or near IRc2. The expansion velocity is 18 km per second, in agreement with the value inferred from water maser observations by Genzel et al. (1981). Because the continuum is intense and likely formed in or near the water-containing gas, the excitation of the observed transitions is dominated by radiative processes. A simple, generalised curve-of-growth method is presented and used to analyze the data. A mean excitation temperature of 72 K and a total water column density of 1.5e18 molecules per cm squared are inferred, each with an estimated maximum uncertainty of 20%. Combined with the molecular hydrogen column density derived from ISO observations of the pure rotational lines, and an assumed temperature of 200-350 K, the inferred water abundance is 2e-4 to 5e-4 in the warm shocked gas. This abundance is similar to that found recently by Harwit et al. (1998) toward Orion using data from the LWS, but higher than that found for most other shocked regions by, for example, Liseau et al. (1996).

C. M. Wright; E. F. van Dishoeck; J. H. Black; H. Feuchtgruber; J. Cernicharo; E. Gonzalez-Alfonso; Th. de Graauw

2000-04-07

359

90 GHz AND 150 GHz OBSERVATIONS OF THE ORION M42 REGION. A SUBMILLIMETER TO RADIO ANALYSIS  

SciTech Connect

We have used the new 90 GHz MUSTANG camera on the Robert C. Byrd Green Bank Telescope (GBT) to map the bright Huygens region of the star-forming region M42 with a resolution of 9'' and a sensitivity of 2.8 mJy beam{sup -1}. Ninety GHz is an interesting transition frequency, as MUSTANG detects both the free-free emission characteristic of the H II region created by the Trapezium stars, normally seen at lower frequencies, and thermal dust emission from the background OMC1 molecular cloud, normally mapped at higher frequencies. We also present similar data from the 150 GHz GISMO camera taken on the IRAM 30 m telescope. This map has 15'' resolution. By combining the MUSTANG data with 1.4, 8, and 21 GHz radio data from the VLA and GBT, we derive a new estimate of the emission measure averaged electron temperature of T{sub e} = 11376 +- 1050 K by an original method relating free-free emission intensities at optically thin and optically thick frequencies. Combining Infrared Space Observatory-long wavelength spectrometer (ISO-LWS) data with our data, we derive a new estimate of the dust temperature and spectral emissivity index within the 80'' ISO-LWS beam toward Orion KL/BN, T{sub d} = 42 +- 3 K and beta {sub d} = 1.3 +- 0.1. We show that both T{sub d} and beta {sub d} decrease when going from the H II region and excited OMC1 interface to the denser UV shielded part of OMC1 (Orion KL/BN, Orion S). With a model consisting of only free-free and thermal dust emission, we are able to fit data taken at frequencies from 1.5 GHz to 854 GHz (350 mum).

Dicker, S. R.; Korngut, P. M.; Devlin, M. J. [University of Pennsylvania, 209 S. 33rd St, Philadelphia, PA 19104 (United States); Mason, B. S.; Cotton, W. D. [National Radio Astronomy Observatory, Charlottesville, VA 22903 (United States); Compiegne, M.; Martin, P. G. [Canadian Institute for Theoretical Astrophysics, University of Toronto, 60 St George St, Toronto, ON M5S 3H8 (Canada); Ade, P. A. R; Tucker, C. [Cardiff University, 5 The Parade, Cardiff, CF24 3YB (United Kingdom); Benford, D. J.; Staguhn, J. G. [NASA Goddard Space Flight Center, Greenbelt, MD 20771 (United States); Irwin, K. D. [National Institute of Standards and Technology, 325 Broadway, Boulder, CO 80305 (United States); Maddalena, R. J.; McMullin, J. P.; Shepherd, D.S. [National Radio Astronomy Observatory, Green Bank, WV 24944 (United States); Sievers, A. [IRAM, Avenida Divina Pastora, 7, Nucleo Central, E 18012 Granada (Spain)

2009-11-01

360

Wetland treatment of oil and gas well waste waters. Final report  

SciTech Connect

Constructed wetlands are small on-site systems that possess three of the most desirable components of an industrial waste water treatment scheme: low cost, low maintenance and upset resistance. The main objective of the present study is to extend the knowledge base of wetland treatment systems to include processes and substances of particular importance to small, on-site systems receiving oil and gas well wastewaters. A list of the most relevant and comprehensive publications on the design of wetlands for water quality improvement was compiled and critically reviewed. Based on our literature search and conversations with researchers in the private sector, toxic organics such as Phenolics and b-naphthoic acid, (NA), and metals such as CU(II) and CR(VI) were selected as target adsorbates. A total of 90 lysimeters equivalent to a laboratory-scale wetland were designed and built to monitor the uptake and transformation of toxic organics and the immobilization of metal ions. Studies on the uptake of toxic organics such as phenol and b-naphthoic acid (NA) and heavy metals such as Cu(II) and Cr(VI), the latter two singly or as non-stoichiometric mixtures by laboratory-type wetlands (LWs) were conducted. These LWs were designed and built during the first year of this study. A road map and guidelines for a field-scale implementation of a wetland system for the treatment of oil and gas wastewaters have been suggested. Two types of wetlands, surface flow (SF) and sub surface flow (SSF), have been considered, and the relative merits of each configuration have been reviewed.

Kadlec, R.; Srinivasan, K.

1995-08-01

361

ISO Key Project: Exploring The Full Range of Quasar/AGN Properties  

NASA Technical Reports Server (NTRS)

While most of the work on this program has been completed, as previously reported, the portion of the program dealing with the sub topic of ISO LWS data analysis and reduction for the LWS Extragalactic Science Team and its leader, Dr. Howard Smith, is still active. This program in fact continues to generate results, and newly available computer modeling has extended the value of the datasets, As a result the team has requested and been granted an obtained a no-cost extension to this program, through December 31, 2003. The essence of the proposal is to perform ISO spectroscopic studies, including data analysis and modeling, of star formation regions using an ensemble of archival space-based data from the Infrared Space Observatory's Long Wavelength Spectrometer and Short Wavelength Spectrometer, but including as well some other spectroscopic data bases. Four kinds of regions are considered in the studies: (1) disks around more evolved objects; (2) young, low or high mass pre-main sequence stars in star formation regions; (3) star formation in external, bright IR galaxies; and (4) the galactic center. One prime focus of the program is the OH lines in the far infrared. The program has the following goals: (1) refine the data analysis of ISO observations, to obtain deeper and better SNR results on selected sources. The ISO data itself underwent "pipeline 10" reductions in early 2001, and additional "hands-on data reduction packages" were supplied by the ISO teams in 2001. The Fabry-Perot database in particularly sensitive to noise can slight calibration errors. (2) model the atomic and molecular line shapes, in particular the OH lines, using revised Monte-Carlo techniques developed by the SWAS team at the Center for Astrophysics; (3) attend scientific meetings and workshops; (4) do E&PO activities related to infrared astrophysics and/or spectroscopy.

Wilkes, Belinda; West, Donald K. (Technical Monitor)

2002-01-01

362

90 GHz and 150 GHz Observations of the Orion M42 Region. A Submillimeter to Radio Analysis  

NASA Technical Reports Server (NTRS)

We have used the new 90GHz MUSTANG camera on the Robert C. Green Bank Telescope (GBT)to map the bright Huygens region of the star-forming region M42 with a resolution of 9" and a sensitivity of 2.8 mJy/beam. Ninety GHz is an interesting transition frequency, as MUSTANG detects both the free-free emission characteristic of the H II region created by the Trapezium stars, normally seen at lower frequencies, and thermal dust emission from the background OMCI molecular cloud, normally mapped at higher frequencies. We also present similar data from the 150 GHz GISMO camera taken on the IRAM 30 m telescope. This map has 15" resolution. By combining the MUSTANG data with 1.4, 8. and 31 GHz radio data from the VLA and GBT, we derive a new estimate of the emission measure averaged electron temperature of T(sub e) = 11376+/-1050 K by an original method relating free-free emission intensities at optically thin and optically thick frequencies. Combining Infrared Space Observatory-long wavelength spectrometer (ISO-LWS) data with our data, we derive a new estimate of the dust temperature and spectral emissivity index within the 80" ISO-LWS beam toward Orion KL/BN, T(sub d) = 42+/-3 K and Beta(sub d) = 1.3+/-0.1. We show that both T(sub d) and Beta(sub d) decrease when going from the H II region and excited OMCI interface to the denser UV shielded part OMCI (Orion KL/BN, Orion S). With a model consisting of only free-free and thermal dust emission, we are able to fit data taken at frequencies from 1.5 GHz to 854 GHz (350 micrometers).

Dicker, S. R.; Mason, B. S.; Korngut, P. M.; Cotton, W. D.; Compiegne, M.; Devlin, M. J.; Martin, P. G.; Ade, P. A. R; Benford, D. J.; Irwin, K. D.; Maddalena, R. J.; McMullin, J. P.; Shepherd, D. S.; Sievers, A.; Staguhn, J. G.; Tucker, C.

2009-01-01

363

The Far Infrared Lines of OH as Molecular Cloud Diagnostics  

NASA Technical Reports Server (NTRS)

Future IR missions should give some priority to high resolution spectroscopic observations of the set of far-IR transitions of OH. There are 15 far-IR lines arising between the lowest eight rotational levels of OH, and ISO detected nine of them. Furthermore, ISO found the OH lines, sometimes in emission and sometimes in absorption, in a wide variety of galactic and extragalactic objects ranging from AGB stars to molecular clouds to active galactic nuclei and ultra-luminous IR galaxies. The ISO/LWS Fabry-Perot resolved the 119 m doublet line in a few of the strong sources. This set of OH lines provides a uniquely important diagnostic for many reasons: the lines span a wide wavelength range (28.9 m to 163.2 m); the transitions have fast radiative rates; the abundance of the species is relatively high; the IR continuum plays an important role as a pump; the contribution from shocks is relatively minor; and, not least, the powerful centimeter-wave radiation from OH allows comparison with radio and VLBI datasets. The problem is that the large number of sensitive free parameters, and the large optical depths of the strongest lines, make modeling the full set a difficult job. The SWAS montecarlo radiative transfer code has been used to analyze the ISO/LWS spectra of a number of objects with good success, including in both the lines and the FIR continuum; the DUSTY radiative transfer code was used to insure a self-consistent continuum. Other far IR lines including those from H2O, CO, and [OI] are also in the code. The OH lines all show features which future FIR spectrometers should be able to resolve, and which will enable further refinements in the details of each cloud's structure. Some examples are given, including the case of S140, for which independent SWAS data found evidence for bulk flows.

Smith, Howard A.

2004-01-01

364

Hot-electron production and suprathermal heat flux scaling with laser intensity from the two-plasmon-decay instability  

SciTech Connect

The fully kinetic reduced-description particle-in-cell (RPIC) method has been applied to simulations of two-plasmon-decay (TPD) instability, driven by crossed laser beams, in an inhomogeneous plasma for parameters consistent with recent direct-drive experiments related to laser-driven inertial fusion. The nonlinear saturated state is characterized by very spiky electric fields, with Langmuir cavitation occurring preferentially inside density channels produced by the ponderomotive beating of the crossed laser beams and the primary TPD Langmuir waves (LWs). The heated electron distribution function is, in all cases, bi-Maxwellian, with instantaneous hot-electron temperatures in the range 60-100 keV. The net hot-electron energy flux out of the system is a small fraction ({approx}1% to 2%) of the input laser intensity in these simulations. Scalings of the hot-electron temperature and suprathermal heat flux as functions of the laser intensity are obtained numerically from RPIC simulations. These simulations lead to the preliminary conclusion that Langmuir cavitation and collapse provide dissipation by producing suprathermal electrons, which stabilize the system in saturation and drive the LW spectrum to the small dissipation scales at the Landau cutoff. The Langmuir turbulence originates at an electron density 0.241 Multiplication-Sign the laser's critical density, where the crossed laser beams excite a 'triad' mode-a common forward LW plus a pair of backward LWs. Remnants of this 'triad' evolve in k-space and dominate the time-averaged energy spectrum. At times exceeding 10 ps, the excited Langmuir turbulence spreads toward lower densities. Comparisons of RPIC simulations with the extended Zakharov model are presented in appropriate regimes, and the necessary requirements for the validity of a quasi-linear Zakharov model (where the spatially averaged electron-velocity distribution is evolved) are verified by RPIC simulation results.

Vu, H. X. [University of California, San Diego, La Jolla, California 92093 (United States); DuBois, D. F. [Lodestar Research Corporation, Boulder, Colorado 80301 (United States); Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States); Myatt, J. F. [Laboratory for Laser Energetics, University of Rochester, Rochester, New York 14623 (United States); Russell, D. A. [Lodestar Research Corporation, Boulder, Colorado 80301 (United States)

2012-10-15

365

THE FUNCTION OF PHOTOMECHANICAL MOVEMENTS IN THE RETINA OF THE RAINBOW TROUT (SALMO GAIRDNERI)  

Microsoft Academic Search

SUMMARY 1. The function of photomechanical movements in the retina of rainbow trout (Salmo gairdneri) was investigated by determining both the effect of light on the level of extractable visual pigment, and the electroretinographic b-wave sensitivity, during various stages of photomechanical light and dark adaptation. 2. Dark-adapted fish, light-adapted fish, and dark-adapted fish exposed to ten minutes direct sunlight had

R. H. DOUGLAS

366

Evolution of clitellate phaosomes from rhabdomeric photoreceptor cells of polychaetes – a study in the leech Helobdella robusta (Annelida, Sedentaria, Clitellata)  

PubMed Central

Introduction In Annelida two types of photoreceptor cells (PRCs) are regarded as generally present, rhabdomeric and ciliary PRCs. In certain taxa, however, an additional type of PRC may occur, the so called phaosomal PRC. Whereas the former two types of PRCs are always organized as an epithelium with their sensory processes projecting into an extracellular cavity formed by the PRCs and (pigmented) supportive cells, phaosomes are seemingly intracellular vacuoles housing the sensory processes. Phaosomal PRCs are the only type of PRC found in one major annelid group, Clitellata. Several hypotheses have been put forward explaining the evolutionary origin of the clitellate phaosomes. To elucidate the evolution of clitellate PRC and eyes the leech Helobdella robusta, for which a sequenced genome is available, was chosen. Results TEM observations showed that extraocular and ocular PRCs are structurally identical. Bioinformatic analyses revealed predictions for four opsin genes, three of which could be amplified. All belong to the rhabdomeric opsin family and phylogenetic analyses showed them in a derived position within annelid opsins. Gene expression studies showed two of them expressed in the eye and in the extraocular PRCs. Polychaete eye-typic key enzymes for ommochromme and pterin shading pigments synthesis are not expressed in leech eyes. Conclusions By comparative gene-expression studies we herein provide strong evidence that the phaosomal PRCs typical of Clitellata are derived from the rhabdomeric PRCs characteristic for polychaete adult eyes. Thus, they represent a highly derived type of PRC that evolved in the stem lineage of Clitellata rather than another, primitive type of PRC in Metazoa. Evolution of these PRCs in Clitellata is related to a loss of the primary eyes and most of their photoreceptive elements except for the rhabdomeric PRCs. Most likely this happened while changing to an endobenthic mode of life. This hypothesis of PRC evolution is in accordance with a recently published phylogeny of Annelida based on phylogenomic data. The data provide a nice example how morphologically highly divergent light sensitive structures emerged from a standard type of photoreceptor cell. PMID:24007384

2013-01-01

367

Europe's space telescope ISO finds water in distant places  

NASA Astrophysics Data System (ADS)

Equally striking is ISO's discovery of water vapour in the outer planets, Saturn, Uranus and Neptune. As those chilly planets cannot release water from within, they probably have a supply of water coming from elsewhere in the Solar System. Since ISO went into orbit at the end of 1995, it has used its unique power of analysing infrared rays coming from the Universe to identify water vapour and water ice near dying stars and newborn stars. It has also measured the water vapour steaming from Comet Hale-Bopp. "Before ISO no instrument was capable of detecting water in so many places," comments ESA's director of science, Roger Bonnet. "To start revealing the cosmic history of the Earth's water is a big success for ESA and for the astronomers who use our unique infrared observatory. And ISO's discovery that water is commonplace in the Galaxy will encourage renewed speculation about life that may exist in the vicinity of other stars." Water amid the stars Primaeval hydrogen atoms make water by joining with oxygen atoms that are manufactured within stars, in nuclear reactions occurring towards the end of a star's life. Oxygen from defunct stars enriches the Galaxy, and abundant hydrogen is available to react with it. Although the existence of water in interstellar space is not surprising, the Earth's moist atmosphere makes life difficult for any astronomer who wishes to spot water vapour in the Universe with ground-based instruments. Observations from aircraft and balloons gave early hints of cosmic water, but thorough investigations had to wait for ISO's unhampered view from space. Three of the satellite's instruments, the Short Wavelength Spectrometer (SWS), the Long Wavelength Spectrometer (LWS) and the photometer ISOPHOT operating in spectroscopic mode, take part in the hunt for water. Last year, for example, users of both SWS and LWS reported water vapour in the vicinity of the aged star, W Hydrae, from which oxygen-rich winds blow into space. The bright infrared source GL 2591, surrounding a newly formed massive star, revealed to SWS hot and abundant water vapour. Jets of gas from very young stars can create luminous shock waves at great distances, and LWS made the first detection of water vapour in such an object, HH-54. Among the objects subsequently examined by LWS, IRAS 16293-2422 is a cosmic egg in the process of creating a star of about the same size as the Sun. Characteristic emissions from water vapour at 108, 113, 174 and 179 microns show up clearly. The water plays a practical part in starmaking. It helps to radiate away excess heat which could otherwise prevent the parent gas from condensing under gravity to make the star. When ISO looks towards the centre of the Galaxy, which lies about 28,000 light-years away in the constellation of Sagittarius, it sees, not emissions of the the characteristic wavelengths of water, but absorptions. These appear as dips in the infrared spectrum and tell of the presence of dark, cool clouds, called molecular clouds, which are the primary source of new stars. Very close to the true Galactic Centre is the bright infrared source Sagittarius B2, and it too shows the presence of water vapour. In a programme of observations which began in the autumn of 1996 and is still continuing, ISO's Long Wavelength Spectrometer has made observations of such high precision that it distinguishes different molecular clouds on the way towards the Galactic Centre. The clouds are moving at different speeds relative to the Earth. They alter each water wavelength by the Doppler effect, to produce a broad absorption line representing water vapour in the various clouds intervening between the Earth and the bright source Sagittarius B2. The detection by LWS of water molecules containing the rare, heavy form of oxygen, oxygen-18, helps the astronomers to estimate the abundance of water. Other watery clouds show up when ISO aims towards other dense regions of the Galaxy somewhat away from the Galactic Centre. There really is, in the words of an English poet, "Water, water everywhere&q

1997-04-01

368

Photochemical activation of TRPA1 channels in neurons and animals  

PubMed Central

Optogenetics is a powerful research tool because it enables high-resolution optical control of neuronal activity. However, current optogenetic approaches are limited to transgenic systems expressing microbial opsins and other exogenous photoreceptors. Here, we identify optovin, a small molecule that enables repeated photoactivation of motor behaviors in wild type animals. Surprisingly, optovin's behavioral effects are not visually mediated. Rather, photodetection is performed by sensory neurons expressing the cation channel TRPA1. TRPA1 is both necessary and sufficient for the optovin response. Optovin activates human TRPA1 via structure-dependent photochemical reactions with redox-sensitive cysteine residues. In animals with severed spinal cords, optovin treatment enables control of motor activity in the paralyzed extremities by localized illumination. These studies identify a light-based strategy for controlling endogenous TRPA1 receptors in vivo, with potential clinical and research applications in non-transgenic animals, including humans. PMID:23396078

Kokel, David; Cheung, Chung Yan J.; Mills, Robert; Coutinho-Budd, Jaeda; Huang, Liyi; Setola, Vincent; Sprague, Jared; Jin, Shan; Jin, Youngnam N.; Huang, Xi-Ping; Bruni, Giancarlo; Woolf, Clifford; Roth, Bryan L.; Hamblin, Michael R; Zylka, Mark J.; Milan, David J.; Peterson, Randall T.

2013-01-01

369

Melatonin Signaling Controls Circadian Swimming Behavior in Marine Zooplankton  

PubMed Central

Summary Melatonin, the “hormone of darkness,” is a key regulator of vertebrate circadian physiology and behavior. Despite its ubiquitous presence in Metazoa, the function of melatonin signaling outside vertebrates is poorly understood. Here, we investigate the effect of melatonin signaling on circadian swimming behavior in a zooplankton model, the marine annelid Platynereis dumerilii. We find that melatonin is produced in brain photoreceptors with a vertebrate-type opsin-based phototransduction cascade and a light-entrained clock. Melatonin released at night induces rhythmic burst firing of cholinergic neurons that innervate locomotor-ciliated cells. This establishes a nocturnal behavioral state by modulating the length and the frequency of ciliary arrests. Based on our findings, we propose that melatonin signaling plays a role in the circadian control of ciliary swimming to adjust the vertical position of zooplankton in response to ambient light. PMID:25259919

Tosches, Maria Antonietta; Bucher, Daniel; Vopalensky, Pavel; Arendt, Detlev

2014-01-01

370

Independent Optical Excitation of Distinct Neural Populations  

PubMed Central

Optogenetic tools enable the causal examination of how specific cell types contribute to brain circuit functions. A long-standing question is whether it is possible to independently activate two distinct neural populations in mammalian brain tissue. Such a capability would enable the examination of how different synapses or pathways interact to support computation. Here we report two new channelrhodopsins, Chronos and Chrimson, obtained through the de novo sequencing and physiological characterization of opsins from over 100 species of algae. Chrimson is 45 nm red-shifted relative to any previous channelrhodopsin, important for scenarios where red light would be preferred; we show minimal visual system mediated behavioral artifact in optogenetically stimulated Drosophila. Chronos has faster kinetics than any previous channelrhodopsin, yet is effectively more light-sensitive. Together, these two reagents enable crosstalk-free two-color activation of neural spiking and downstream synaptic transmission in independent neural populations in mouse brain slice. PMID:24509633

Klapoetke, Nathan C; Murata, Yasunobu; Kim, Sung Soo; Pulver, Stefan R.; Birdsey-Benson, Amanda; Cho, Yong Ku; Morimoto, Tania K; Chuong, Amy S; Carpenter, Eric J; Tian, Zhijian; Wang, Jun; Xie, Yinlong; Yan, Zhixiang; Zhang, Yong; Chow, Brian Y; Surek, Barbara; Melkonian, Michael; Jayaraman, Vivek; Constantine-Paton, Martha; Wong, Gane Ka-Shu; Boyden, Edward S

2014-01-01

371

The developing and evolving retina: using time to organize form.  

PubMed

Evolutionary and other functional accounts of the retina and its normal development highlight different aspects of control of its growth and form than genomic and mechanistic accounts. Discussing examples from opsin expression, developmental regulation of the eye's size and optical quality, regulation of eye size with respect to brain and body size, and the development of the fovea, these different aspects of control are contrasted. Contributions of mouse models, particularly with regard to relative timing of events in different species are reviewed, introducing a Web-based utility for exploration of timing issues (www.translatingtime.net). Variation at the individual level, in early experience, and also across species is an essential source of information to understand normal development and its pathologies. PMID:17692298

Finlay, Barbara L

2008-02-01

372

Melanopsin and inner retinal photoreception.  

PubMed

Over the last ten years there has been growing acceptance that retinal photoreception among mammals extends beyond rods and cones to include a small number of intrinsically photosensitive retinal ganglion cells (ipRGCs). These ipRGCs are capable of responding to light in the absence of rod/cone input thanks to expression of an opsin photopigment called melanopsin. They are specialised for measuring ambient levels of light (irradiance) for a wide variety of so-called non-image-forming light responses. These include synchronisation of circadian clocks to light:dark cycles and the regulation of pupil size, sleep propensity and pineal melatonin production. Here, we provide a review of some of the landmark discoveries in this fast developing field, paying particular emphasis to recent findings and key areas for future investigation. PMID:19865798

Bailes, Helena J; Lucas, Robert J

2010-01-01

373

bcl-2 overexpression reduces apoptotic photoreceptor cell death in three different retinal degenerations.  

PubMed Central

Apoptosis of photoreceptors occurs infrequently in adult retina but can be triggered in inherited and environmentally induced retinal degenerations. The protooncogene bcl-2 is known to be a potent regulator of cell survival in neurons. We created lines of transgenic mice overexpressing bcl-2 to test for its ability to increase photoreceptor survival. Bcl-2 increased photoreceptor survival in mice with retinal degeneration caused by a defective opsin or cGMP phosphodiesterase. Overexpression of Bcl-2 in normal photoreceptors also decreased the damaging effects of constant light exposure. Apoptosis was induced in normal photoreceptors by very high levels of bcl-2. We conclude that bcl-2 is an important regulator of photoreceptor cell death in retinal degenerations. Images Fig. 1 Fig. 2 Fig. 3 Fig. 5 PMID:8692941

Chen, J; Flannery, J G; LaVail, M M; Steinberg, R H; Xu, J; Simon, M I

1996-01-01

374

A glimpse into the basis of vision in the kingdom Mycota  

PubMed Central

Virtually all organisms exposed to light are capable of sensing this environmental signal. In recent years the photoreceptors that mediate the ability of fungi to “see” have been identified in diverse species, and increasingly characterized. The small sizes of fungal genomes and ease in genetic and molecular biology manipulations make this kingdom ideal amongst the eukaryotes for understanding photosensing. The most widespread and conserved photosensory protein in the fungi is White collar 1 (WC-1), a flavin-binding photoreceptor that functions with WC-2 as a transcription factor complex. Other photosensory proteins in fungi include opsins, phytochromes and cryptochromes whose roles in fungal photobiology are not fully resolved and their distribution in the fungi requires further taxon sampling. Additional unknown photoreceptors await discovery. This review discusses the effects of light on fungi and the evolutionary processes that may have shaped the ability of species to sense and respond to this signal. PMID:20451644

Idnurm, Alexander; Verma, Surbhi; Corrochano, Luis M.

2010-01-01

375

THE VISUAL SYSTEM OF THE ALLIGATOR  

PubMed Central

The eye tissues and liver of the alligator contain vitamin A1 alone. The retina contains rhodopsin, typical in absorption spectrum (?max 500 mµ); but synthesized in solution from neo-b retinene and opsin much more rapidly than are the frog, mammalian, or chicken rhodopsins previously examined. In this regard alligator rhodopsin resembles the rhodopsins and porphyropsins of fishes, all of which so far investigated are synthesized rapidly in solution. The rates of synthesis in vitro of frog and alligator rhodopsins are matched closely by the rates of rod dark adaptation in living frogs and alligators, measured electrophysiologically at the same temperature. Alligator rods dark-adapt, and alligator rhodopsin is synthesized in solution, at rates characteristically associated with cones and cone pigments in frogs, mammals, and birds. PMID:13428984

Wald, George; Brown, Paul K.; Kennedy, Donald

1957-01-01

376

Enlightening the brain: Linking deep brain photoreception with behavior and physiology  

PubMed Central

Vertebrates respond to light with more than just their eyes. In this article we speculate on the intriguing possibility that a link remains between non-visual opsins and neurohormonal systems that control neuronal circuit formation and activity in mammals. Historically, the retina and pineal gland were considered the only significant light-sensing tissues in vertebrates. However, over the last century evidence has accumulated arguing that extra-ocular tissues in vertebrates influence behavior through non-image-forming photoreception. One such class of extra-ocular light detectors are the long mysterious deep brain photoreceptors. Here we review recent findings on the cellular identity and the function of deep brain photoreceptors controlling behavior and physiology in zebrafish, and discuss their implications. PMID:23712321

Fernandes, António M.; Fero, Kandice; Driever, Wolfgang; Burgess, Harold A.

2014-01-01

377

Characterisation of the RNA interference response against the long-wavelength receptor of the honeybee.  

PubMed

Targeted knock-down is the method of choice to advance the study of sensory and brain functions in the honeybee by using molecular techniques. Here we report the results of a first attempt to interfere with the function of a visual receptor, the long-wavelength-sensitive (L-) photoreceptor. RNA interference to inhibit this receptor led to a reduction of the respective mRNA and protein. The interference effect was limited in time and space, and its induction depended on the time of the day most probably because of natural daily variations in opsin levels. The inhibition did not effectively change the physiological properties of the retina. Possible constraints and implications of this method for the study of the bee's visual system are discussed. Overall this study underpins the usefulness and feasibility of RNA interference as manipulation tool in insect brain research. PMID:23933285

Leboulle, Gérard; Niggebrügge, Claudia; Roessler, Reinhard; Briscoe, Adriana D; Menzel, Randolf; Hempel de Ibarra, Natalie

2013-10-01

378

Light as a central modulator of circadian rhythms, sleep and affect  

PubMed Central

Light has profoundly influenced the evolution of life on earth. As widely appreciated, light allows us to generate images of our environment. However, light, through the atypical intrinsically photosensitive retinal ganglion cells (ipRGCs; Box 1), also influences behaviors that are essential for our health and quality of life, yet are independent of image formation. These include the synchronization of the circadian clock to the solar day, tracking of seasonal changes, and regulation of sleep. Irregular light environments lead to problems in circadian rhythms and sleep, which eventually cause mood and learning deficits. Recently, it was found that irregular light can also directly impact mood and learning without producing major disruptions in circadian rhythms and sleep. Here, we will discuss the indirect and direct influence of light on mood and learning and provide a model for how light, the circadian clock, and sleep interact to influence mood and cognitive functions. Box 1Intrinsically photosensitive retinal ganglion cells (ipRGCs)Retinal photoreceptors transduce light energy into electrical signals that initiate vision. The classical photoreceptors, rods and cones, possess modified cilia that consist of stacks of membranes in which photopigments (rhodopsin and cone opsins) are concentrated. Rods are exquisitely sensitive and are able to detect even a few photons. Rods are therefore used for night vision. Cones are less sensitive than rods and are used for day and color vision. Color vision is mediated by cone photoreceptors that express cone-opsins with sensitivity peaks at different wavelengths (colors) of light. Humans have three cone types: short, mid and long wavelength sensitive cones (for simplicity, we will refer to these as blue, green and red cones, respectively). Rods and cones relay photic information through multisynaptic pathways to retinal ganglion cells (RGCs), which innervate different areas in the brain for complex visual processing13.A surprising discovery showed that a subpopulation of RGCs is intrinsically photosensitive and express the photopigment melanopsin. These cells were thus termed ipRGCs17–19. The melanopsin gene (Opn4) was originally cloned from Xenopus laevis dermal melanophores, and was shown to have orthologs in many mammalian species, including humans141. Sequence analysis shows that melanopsin shares more homology with invertebrate opsins than with vertebrate opsins, suggesting that melanopsin may use a different mechanism for light signaling than that used by the photopigments present in the rods and cones of vertebrates142. ipRGCs do not have modified membranes in which the photopigment can be concentrated: thus, melanopsin protein is expressed uniformly throughout the soma, dendrites, and the initial segment of the axon143. The lack of membrane specialization makes ipRGCs less sensitive to light than rods and cones. However, ipRGCs are able to incorporate light signals over extended period of time, resulting in an increase in their sensitivity during prolonged light stimulation. ipRGCs are most sensitive to wavelengths of light that are in the blue region of the light spectrum144, 145. As ganglion cells, ipRGCs also convey light information from rods and cones in addition to their intrinsic melanopsin-dependent pathway and can control a variety of light-mediated behaviors30.Originally, ipRGCs were thought to comprise a uniform population, however, recent discoveries revealed that ipRGCs are highly diverse, comprising at least five distinct subtypes (M1-M5) in rodents based on morphological and electrophysiological analyses22–29. The originally identified population is now known as M1 ipRGCs and project predominantly to brain regions involved in non-image forming visual functions, whereas the non-M1 ipRGCs show widespread projections to areas in the brain important for image formation. ipRGC subtypes express varying levels of the melanopsin protein and have different patterns of dendrite stratification in the inner plexiform layer (IPL)27, 28, 146, 147, indicating

LeGates, T.A.; Fernandez, D.C.; Hattar, S

2014-01-01

379

Topography of the long- to middle-wavelength sensitive cone ratio in the human retina assessed with a wide-field color multifocal electroretinogram  

PubMed Central

The topographical distribution of relative sensitivity to red and green lights across the retina was assayed using a custom-made wide-field color multifocal electroretinogram apparatus. There were increases in the relative sensitivity to red compared to green light in the periphery that correlate with observed increases in the relative amount of long (L) compared to middle (M) wavelength sensitive opsin mRNA. These results provide electrophysiological evidence that there is a dramatic increase in the ratio of L to M cones in the far periphery of the human retina. The central to far peripheral homogeneity in cone proportions has implications for understanding the developmental mechanisms that determine the identity of a cone as L or M and for understanding the circuitry for color vision in the peripheral retina. PMID:18598401

Kuchenbecker, James A.; Sahay, Manisha; Tait, Diane M.; Neitz, Maureen; Neitz, Jay

2008-01-01

380

New insights into retinoid metabolism and cycling within the retina  

PubMed Central

The retinoid cycle is a series of biochemical reactions within the eye that is responsible for synthesizing the chromophore, 11-cis retinal, for visual function. The chromophore is bound to G-protein coupled receptors, opsins, within rod and cone photoreceptor cells forming the photosensitive visual pigments. Integral to the sustained function of photoreceptors is the continuous generation of chromophore by the retinoid cycle through two separate processes, one that supplies both rods and cones and another that exclusively supplies cones. Recent findings such as RPE65 localization within cones and the pattern of distribution of retinoid metabolites within mouse and human retinas have challenged previous proposed schemes. This review will focus on recent findings regarding the transport of retinoids, the mechanisms by which chromophore is supplied to both rods and cones, and the metabolism of retinoids within the posterior segment of the eye. PMID:23063666

Tang, Peter H.; Kono, Masahiro; Koutalos, Yiannis; Ablonczy, Zsolt; Crouch, Rosalie K.

2013-01-01

381

QM/MM Study of Dehydro and Dihydro ?-Ionone Retinal Analogues in Squid and Bovine Rhodopsins: Implications for Vision in Salamander Rhodopsin  

PubMed Central

Visual pigment rhodopsin provides a decisive crossing point for interaction between organisms and environment. Naturally occurring visual pigments contain only PSB11 and 3,4-dehydro-PSB11 as chromophores. Therefore, the ability of visual opsin to discriminate between the retinal geometries is investigated by means of QM/MM incorporation of PSB11, 6-s-cis and 6-s-trans forms of 3,4-dehydro-PSB11, 3,4-dehydro-5,6-dihydro-PSB11, 5,6-dihydro-PSB11 analogues into squid and bovine rhodopsin environments. The analogue-protein interaction reveals the binding site of squid rhodopsin to be malleable and ductile, while that of bovine rhodopsin to be rigid and stiff. On the basis of these studies, a tentative model of salamander rhodopsin binding site is also proposed. PMID:20964383

Sekharan, Sivakumar; Altun, Ahmet; Morokuma, Keiji

2010-01-01

382

Vitamin A activates rhodopsin and sensitizes it to ultraviolet light  

PubMed Central

The visual pigment, rhodopsin, consists of opsin protein with 11-cis retinal chromophore, covalently bound. Light activates rhodopsin by isomerizing the chromophore to the all-trans conformation. The activated rhodopsin sets in motion a biochemical cascade that evokes an electrical response by the photoreceptor. All-trans retinal is eventually released from the opsin and reduced to vitamin A. Rod and cone photoreceptors contain vast amounts of rhodopsin, so after exposure to bright light, the concentration of vitamin A can reach relatively high levels within their outer segments. Since a retinal analog, ?-ionone, is capable of activating some types of visual pigments, we tested whether vitamin A might produce a similar effect. In single-cell recordings from isolated dark-adapted salamander green-sensitive rods, exogenously applied vitamin A decreased circulating current and flash sensitivity and accelerated flash response kinetics. These changes resembled those produced by exposure of rods to steady light. Microspectrophotometric measurements showed that vitamin A accumulated in the outer segments and binding of vitamin A to rhodopsin was confirmed in in vitro assays. In addition, vitamin A improved the sensitivity of photoreceptors to ultraviolet (UV) light. Apparently, the energy of a UV photon absorbed by vitamin A transferred by a radiationless process to the 11-cis retinal chromophore of rhodopsin, which subsequently isomerized. Therefore, our results suggest that vitamin A binds to rhodopsin at an allosteric binding site distinct from the chromophore binding pocket for 11-cis retinal to activate the rhodopsin, and that it serves as a sensitizing chromophore for UV light. PMID:22192505

Miyazono, Sadaharu; Isayama, Tomoki; Delori, François C.; Makino, Clint L.

2013-01-01

383

Evolution of Mammalian Opn5 as a Specialized UV-absorbing Pigment by a Single Amino Acid Mutation*  

PubMed Central

Opn5 is one of the recently identified opsin groups that is responsible for nonvisual photoreception in animals. We previously showed that a chicken homolog of mammalian Opn5 (Opn5m) is a Gi-coupled UV sensor having molecular properties typical of bistable pigments. Here we demonstrated that mammalian Opn5m evolved to be a more specialized photosensor by losing one of the characteristics of bistable pigments, direct binding of all-trans-retinal. We first confirmed that Opn5m proteins in zebrafish, Xenopus tropicalis, mouse, and human are also UV-sensitive pigments. Then we found that only mammalian Opn5m proteins lack the ability to directly bind all-trans-retinal. Mutational analysis showed that these characteristics were acquired by a single amino acid replacement at position 168. By comparing the expression patterns of Opn5m between mammals and chicken, we found that, like chicken Opn5m, mammalian Opn5m was localized in the ganglion cell layer and inner nuclear layer of the retina. However, the mouse and primate (common marmoset) opsins were distributed not in the posterior hypothalamus (including the region along the third ventricle) where chicken Opn5m is localized, but in the preoptic hypothalamus. Interestingly, RPE65, an essential enzyme for forming 11-cis-retinal in the visual cycle is expressed near the preoptic hypothalamus of the mouse and common marmoset brain but not near the region of the chicken brain where chicken Opn5m is expressed. Therefore, mammalian Opn5m may work exclusively as a short wavelength sensor in the brain as well as in the retina with the assistance of an 11-cis-retinal-supplying system. PMID:24403072

Yamashita, Takahiro; Ono, Katsuhiko; Ohuchi, Hideyo; Yumoto, Akane; Gotoh, Hitoshi; Tomonari, Sayuri; Sakai, Kazumi; Fujita, Hirofumi; Imamoto, Yasushi; Noji, Sumihare; Nakamura, Katsuki; Shichida, Yoshinori

2014-01-01

384

Computational molecular phenotyping of retinal sheet transplants to rats with retinal degeneration  

PubMed Central

Retinal progenitor sheet transplants have been shown to extend neuronal processes into a degenerating host retina and to restore visual responses in the brain. The aim of this study was the first attempt to identify cells involved in transplant signals to retinal degenerate hosts using computational molecular phenotyping (CMP). - S334ter line 3 rats received fetal retinal sheet transplants at the age of 24-40d. Donor tissues were incubated with slow-releasing microspheres containing BDNF or GDNF. Up to 265 days after surgery, eyes of selected rats were vibratome sectioned through the transplant area (some slices stained for donor marker hPAP), dehydrated and embedded in Eponate, sectioned into serial ultrathin datasets and probed for rhodopsin, cone opsin, CRALBP, L-glutamate, L-glutamine, glutathione, glycine, taurine, GABA, and DAPI. - In large transplant areas, photoreceptor outer segments in contact with host RPE revealed rod and cone opsin immunoreactivity whereas no such staining was found in the degenerate host retina. Transplant photoreceptor layers contained high taurine levels. Glutamate levels in the transplants were higher than in the host retina whereas GABA levels were similar. The transplant inner nuclear layer showed some loss of neurons, but amacrine cells and horizontal cells were not reduced. In many areas, glial hypertrophy between the host and transplant was absent and host and transplant neuropil appeared to intermingle. CMP data indicate that horizontal cells and both glycinergic and GABAergic amacrine cells are involved in a novel circuit between transplant and host, generating alternative signal pathways between transplant and degenerating host retina. PMID:22594836

Seiler, M.J.; Jones, B.W.; Aramant, R.B.; Yang, P.B.; Keirstead, H.S.; Marc, R.E.

2012-01-01

385

Retinal biosynthesis in fungi: characterization of the carotenoid oxygenase CarX from Fusarium fujikuroi.  

PubMed

The car gene cluster of the ascomycete Fusarium fujikuroi encodes two enzymes responsible for torulene biosynthesis (CarRA and CarB), an opsin-like protein (CarO), and a putative carotenoid cleaving enzyme (CarX). It was presumed that CarX catalyzes the formation of the major carotenoid in F. fujikuroi, neurosporaxanthin, a cleavage product of torulene. However, targeted deletion of carX did not impede neurosporaxanthin biosynthesis. On the contrary, DeltacarX mutants showed a significant increase in the total carotenoid content, indicating an involvement of CarX in the regulation of the pathway. In this work, we investigated the enzymatic activity of CarX. The expression of the enzyme in beta-carotene-accumulating Escherichia coli cells led to the formation of the opsin chromophore retinal. The identity of the product was proven by high-performance liquid chromatography and gas chromatography-mass spectrometry. Subsequent in vitro assays with heterologously expressed and purified CarX confirmed its beta-carotene-cleaving activity and revealed its capability to produce retinal also from other substrates, such as gamma-carotene, torulene, and beta-apo-8'-carotenal. Our data indicate that the occurrence of at least one beta-ionone ring in the substrate is required for the cleavage reaction and that the cleavage site is determined by the distance to the beta-ionone ring. CarX represents the first retinal-synthesizing enzyme reported in the fungal kingdom so far. It seems likely that the formed retinal is involved in the regulation of the carotenoid biosynthetic pathway via a negative feedback mechanism. PMID:17293483

Prado-Cabrero, Alfonso; Scherzinger, Daniel; Avalos, Javier; Al-Babili, Salim

2007-04-01

386

Effects of different colors of light on melatonin suppression and expression analysis of Aanat1 and melanopsin in the eye of a tropical damselfish.  

PubMed

Ocular melatonin production exhibits a daily rhythm with a decrease during photophase and an increase during scotophase (nocturnal pattern) in teleost fish due to day-night changes in the activity of the rate-limiting melatonin synthesizing enzyme arylalkylamine N-acetyltransferase (AANAT). Acute light exposure during scotophase suppresses AANAT activity and melatonin production in the eyes, suggesting that external light signals are a principal regulator of ocular melatonin synthesis. To better understand the photic regulation of ocular melatonin synthesis in teleost fish, this study sought to characterize the effect of light on ocular melatonin synthesis in the sapphire devil Chrysiptera cyanea, which shows a nocturnal pattern and light-induced inhibition of ocular melatonin production during scotophase. Exposure to three different wavelengths of light (half-peak bandwidth=435-475 nm with a peak of 455 nm, 495-565 nm with a peak of 530 nm, and 607-647 nm with a peak of 627 nm for the blue, green, and red LEDs) for 2h during scotophase resulted in the blue wavelength significantly decreasing ocular melatonin content within 30 min after light exposure. This result clearly indicates that the effective range of visible light on ocular melatonin suppression is distributed within the wavelengths of blue light and that a blue light-sensitive opsin is involved in ocular melatonin suppression in the fish. A PCR-based cloning method revealed the expression of melanopsin, a putative blue light-sensitive nonvisual opsin, in the eyes. Furthermore, in situ hybridization using the sapphire devil Aanat1 and melanopsin RNA probes showed mRNA expressions of both genes in the inner nuclear and ganglion cell layer of the fish retina. These results suggest that melanopsin is a possible candidate photoreceptor involved in ocular melatonin suppression by an external light signal in the sapphire devil. PMID:24859252

Takeuchi, Yuki; Imamura, Satoshi; Sawada, Yuji; Hur, Sung-Pyo; Takemura, Akihiro

2014-08-01

387

Evolution of rhodopsin ion pumps in haloarchaea  

PubMed Central

Background The type 1 (microbial) rhodopsins are a diverse group of photochemically reactive proteins that display a broad yet patchy distribution among the three domains of life. Recent work indicates that this pattern is likely the result of lateral gene transfer (LGT) of rhodopsin genes between major lineages, and even across domain boundaries. Within the lineage in which the microbial rhodopsins were initially discovered, the haloarchaea, a similar patchy distribution is observed. In this initial study, we assess the roles of LGT and gene loss in the evolution of haloarchaeal rhodopsin ion pump genes, using phylogenetics and comparative genomics approaches. Results Mapping presence/absence of rhodopsins onto the phylogeny of the RNA polymerase B' subunit (RpoB') of the haloarchaea supports previous notions that rhodopsins are patchily distributed. The phylogeny for the bacteriorhodopsin (BR) protein revealed two discrepancies in comparison to the RpoB' marker, while the halorhodopsin (HR) tree showed incongruence to both markers. Comparative analyses of bacteriorhodopsin-linked regions of five haloarchaeal genomes supported relationships observed in the BR tree, and also identified two open reading frames (ORFs) that were more frequently linked to the bacteriorhodopsin gene than those genes previously shown to be important to the function and expression of BR. Conclusion The evidence presented here reveals a complex evolutionary history for the haloarchaeal rhodopsins, with both LGT and gene loss contributing to the patchy distribution of rhodopsins within this group. Similarities between the BR and RpoB' phylogenies provide supportive evidence for the presence of bacteriorhodopsin in the last common ancestor of haloarchaea. Furthermore, two loci that we have designated bacterio-opsin associated chaperone (bac) and bacterio-opsin associated protein (bap) are inferred to have important roles in BR biogenesis based on frequent linkage and co-transfer with bacteriorhodopsin genes. PMID:17511874

Sharma, Adrian K; Walsh, David A; Bapteste, Eric; Rodriguez-Valera, Francisco; Ford Doolittle, W; Papke, R Thane

2007-01-01

388

Effect of vitamin A supplementation on rhodopsin mutants threonine-17 ? methionine and proline-347 ? serine in transgenic mice and in cell cultures  

PubMed Central

A therapeutic effect of vitamin A supplementation on the course of photoreceptor degeneration, previously reported for patients with retinitis pigmentosa, was tested in two transgenic mouse models of this disease, each carrying a dominant rhodopsin mutation. The threonine-17 ? methionine (T17M) mutation is a class II rhodopsin mutation, characterized by a thermal instability/folding defect and minimal regeneration with the chromophore. The proline-347 ? serine (P347S) mutation belongs to class I, comprised of a smaller number of mutations that exhibit no recognized biochemical abnormality in vitro. In the present study, each of the two mouse models was fed a diet containing 2.5 mg of vitamin A palmitate (control) or 102.5 mg of vitamin A palmitate (high vitamin A) per kilogram of diet. Dark-adapted, full-field electroretinograms showed that the high vitamin A diet significantly reduced the rate of decline of a-wave and b-wave amplitudes in the T17M mice but had no significant effect on the decline of electroretinogram amplitude in the P347S mice. Correspondingly, histologic evaluation revealed that the treatment was associated with significantly longer photoreceptor inner and outer segments and a thicker outer nuclear layer in the T17M mice but had no effect on photoreceptor morphology in the P347S mice. In a separate series of experiments, the instability defect of the T17M mutant opsin expressed in vitro was partially alleviated by inclusion of 11-cis-retinal in the culture media. These results show that vitamin A supplementation slows the rate of photoreceptor degeneration caused by a class II rhodopsin mutation. Vitamin A supplementation may confer therapeutic benefit by stabilizing mutant opsins through increased availability of the chromophore. PMID:9751768

Li, Tiansen; Sandberg, Michael A.; Pawlyk, Basil S.; Rosner, Bernard; Hayes, K. C.; Dryja, Thaddeus P.; Berson, Eliot L.

1998-01-01

389

Effect of vitamin A supplementation on rhodopsin mutants threonine-17 --> methionine and proline-347 --> serine in transgenic mice and in cell cultures.  

PubMed

A therapeutic effect of vitamin A supplementation on the course of photoreceptor degeneration, previously reported for patients with retinitis pigmentosa, was tested in two transgenic mouse models of this disease, each carrying a dominant rhodopsin mutation. The threonine-17 --> methionine (T17M) mutation is a class II rhodopsin mutation, characterized by a thermal instability/folding defect and minimal regeneration with the chromophore. The proline-347 --> serine (P347S) mutation belongs to class I, comprised of a smaller number of mutations that exhibit no recognized biochemical abnormality in vitro. In the present study, each of the two mouse models was fed a diet containing 2.5 mg of vitamin A palmitate (control) or 102.5 mg of vitamin A palmitate (high vitamin A) per kilogram of diet. Dark-adapted, full-field electroretinograms showed that the high vitamin A diet significantly reduced the rate of decline of a-wave and b-wave amplitudes in the T17M mice but had no significant effect on the decline of electroretinogram amplitude in the P347S mice. Correspondingly, histologic evaluation revealed that the treatment was associated with significantly longer photoreceptor inner and outer segments and a thicker outer nuclear layer in the T17M mice but had no effect on photoreceptor morphology in the P347S mice. In a separate series of experiments, the instability defect of the T17M mutant opsin expressed in vitro was partially alleviated by inclusion of 11-cis-retinal in the culture media. These results show that vitamin A supplementation slows the rate of photoreceptor degeneration caused by a class II rhodopsin mutation. Vitamin A supplementation may confer therapeutic benefit by stabilizing mutant opsins through increased availability of the chromophore. PMID:9751768

Li, T; Sandberg, M A; Pawlyk, B S; Rosner, B; Hayes, K C; Dryja, T P; Berson, E L

1998-09-29

390

Lake and Sea Populations of Mysis relicta (Crustacea, Mysida) with Different Visual-Pigment Absorbance Spectra Use the Same A1 Chromophore  

PubMed Central

Glacial-relict species of the genus Mysis (opossum shrimps) inhabiting both fresh-water lakes and brackish sea waters in northern Europe show a consistent lake/sea dichotomy in eye spectral sensitivity. The absorbance peak (?max) recorded by microspectrophotometry in isolated rhabdoms is invariably 20–30 nm red-shifted in “lake” compared with “sea” populations. The dichotomy holds across species, major opsin lineages and light environments. Chromophore exchange from A1 to A2 (retinal ? 3,4-didehydroretinal) is a well-known mechanism for red-shifting visual pigments depending on environmental conditions or stages of life history, present not only in fishes and amphibians, but in some crustaceans as well. We tested the hypothesis that the lake/sea dichotomy in Mysis is due to the use of different chromophores, focussing on two populations of M. relicta from, respectively, a Finnish lake and the Baltic Sea. They are genetically very similar, having been separated for less than 10 kyr, and their rhabdoms show a typical lake/sea difference in ?max (554 nm vs. 529 nm). Gene sequencing has revealed no differences translating into amino acid substitutions in the transmembrane parts of their opsins. We determined the chromophore identity (A1 or A2) in the eyes of these two populations by HPLC, using as standards pure chromophores A1 and A2 as well as extracts from bovine (A1) and goldfish (A2) retinas. We found that the visual-pigment chromophore in both populations is A1 exclusively. Thus the spectral difference between these two populations of M. relicta is not due to the use of different chromophores. We argue that this conclusion is likely to hold for all populations of M. relicta as well as its European sibling species. PMID:24516590

Belikov, Nikolai; Yakovleva, Marina; Feldman, Tatiana; Demina, Olga; Khodonov, Andrei; Lindström, Magnus; Donner, Kristian; Ostrovsky, Mikhail

2014-01-01

391

Adaptive evolution of color vision as seen through the eyes of butterflies.  

PubMed

Butterflies and primates are interesting for comparative color vision studies, because both have evolved middle- (M) and long-wavelength- (L) sensitive photopigments with overlapping absorbance spectrum maxima (lambda(max) values). Although positive selection is important for the maintenance of spectral variation within the primate pigments, it remains an open question whether it contributes similarly to the diversification of butterfly pigments. To examine this issue, we performed epimicrospectrophotometry on the eyes of five Limenitis butterfly species and found a 31-nm range of variation in the lambda(max) values of the L-sensitive photopigments (514-545 nm). We cloned partial Limenitis L opsin gene sequences and found a significant excess of replacement substitutions relative to polymorphisms among species. Mapping of these L photopigment lambda(max) values onto a phylogeny revealed two instances within Lepidoptera of convergently evolved L photopigment lineages whose lambda(max) values were blue-shifted. A codon-based maximum-likelihood analysis indicated that, associated with the two blue spectral shifts, four amino acid sites (Ile17Met, Ala64Ser, Asn70Ser, and Ser137Ala) have evolved substitutions in parallel and exhibit significant d(N)/d(S) >1. Homology modeling of the full-length Limenitis arthemis astyanax L opsin placed all four substitutions within the chromophore-binding pocket. Strikingly, the Ser137Ala substitution is in the same position as a site that in primates is responsible for a 5- to 7-nm blue spectral shift. Our data show that some of the same amino acid sites are under positive selection in the photopigments of both butterflies and primates, spanning an evolutionary distance >500 million years. PMID:17494749

Frentiu, Francesca D; Bernard, Gary D; Cuevas, Cristina I; Sison-Mangus, Marilou P; Prudic, Kathleen L; Briscoe, Adriana D

2007-05-15

392

Adaptive evolution of color vision as seen through the eyes of butterflies  

PubMed Central

Butterflies and primates are interesting for comparative color vision studies, because both have evolved middle- (M) and long-wavelength- (L) sensitive photopigments with overlapping absorbance spectrum maxima (?max values). Although positive selection is important for the maintenance of spectral variation within the primate pigments, it remains an open question whether it contributes similarly to the diversification of butterfly pigments. To examine this issue, we performed epimicrospectrophotometry on the eyes of five Limenitis butterfly species and found a 31-nm range of variation in the ?max values of the L-sensitive photopigments (514–545 nm). We cloned partial Limenitis L opsin gene sequences and found a significant excess of replacement substitutions relative to polymorphisms among species. Mapping of these L photopigment ?max values onto a phylogeny revealed two instances within Lepidoptera of convergently evolved L photopigment lineages whose ?max values were blue-shifted. A codon-based maximum-likelihood analysis indicated that, associated with the two blue spectral shifts, four amino acid sites (Ile17Met, Ala64Ser, Asn70Ser, and Ser137Ala) have evolved substitutions in parallel and exhibit significant dN/dS >1. Homology modeling of the full-length Limenitis arthemis astyanax L opsin placed all four substitutions within the chromophore-binding pocket. Strikingly, the Ser137Ala substitution is in the same position as a site that in primates is responsible for a 5- to 7-nm blue spectral shift. Our data show that some of the same amino acid sites are under positive selection in the photopigments of both butterflies and primates, spanning an evolutionary distance >500 million years. PMID:17494749

Frentiu, Francesca D.; Bernard, Gary D.; Cuevas, Cristina I.; Sison-Mangus, Marilou P.; Prudic, Kathleen L.; Briscoe, Adriana D.

2007-01-01

393

PEDF and GDNF are key regulators of photoreceptor development and retinal neurogenesis in reaggregates from chick embryonic retina.  

PubMed

Here, role(s) of pigment epithelial-derived factor (PEDF) and glial-derived neurotrophic factor (GDNF) on photoreceptor development in three-dimensional reaggregates from the retinae of the E6 chick embryo (rosetted spheroids) was investigated. Fully dispersed cells were reaggregated under serum-reduced conditions and supplemented with 50 ng/ml PEDF alone or in combination with 50 ng/ml GDNF. The spheroids were analyzed for cell growth, differentiation, and death using proliferating cell nuclear antigen, terminal deoxynucleotidyl transferase deoxyuridine triphosphate nick end labeling, and other immunocytochemical stainings and semi-quantitative reverse transcription polymerase chain reaction (RT-PCR) methods. PEDF strongly promoted synthesis of the messenger RNAs for blue and violet cone opsins and to a lesser extent on the red and green cone opsins. This correlated with an increase in the number of cone photoreceptors, as determined by the cone cell marker CERN906. Likewise, PEDF nearly completely inhibited rod differentiation, as detected by immunostaining with anti-rho4D2 and RT-PCR. Furthermore, PEDF accelerated proliferation of cells in the spheroids and inhibited apoptosis. As negative effects, PEDF inhibited the normal histotypic tissue formation of retinal aggregates and reduced the frequency of photoreceptor rosettes and IPL-like areas. Noticeably, supplementation of PEDF-treated cultures with GDNF reversed the effects of PEDF on spheroid morphology and on rod differentiation. This study establishes that PEDF strongly affects three-dimensional retinogenesis in vitro, most notably by inhibiting rod development and supporting proliferation and differentiation of cones, effects which are partially counteracted by GDNF. PMID:20072641

Volpert, Katja N; Tombran-Tink, Joyce; Barnstable, Colin; Layer, Paul G

2009-01-01

394

Retinal morphological and functional changes in an animal model of retinitis pigmentosa.  

PubMed

The P23H-1 transgenic rat carries a mutated mouse opsin gene, in addition to endogenous opsin genes, and undergoes progressive photoreceptor loss that is generally characteristic of human autosomal dominant retinitis pigmentosa (RP). Here, we examined morphological changes correlated with visual function that is comparable to clinical application in the pigmented P23H-1 rat retina as photoreceptor degeneration progressed. We found that rod function was compromised as early as postnatal day 28 and was a good indicator for tracking retinal degeneration. Cone function was normal and did not change until the thickness of the photoreceptor layer was reduced by 75%. Similar to the threshold versus intensity curves used to evaluate vision of RP patients, light-adaptation curves showed that cone thresholds depended on the number of remaining functioning cones, but not on its length of outer segments (OS). By 1 year of age, both rod and cone functions were significantly compromised. Correlating with early abnormal rod function, rods and related secondary neurons also underwent progressive degeneration, including shortening of inner and OS of photoreceptors, loss of rod bipolar and horizontal cell dendrites, thickening of the outer Müller cell processes, and reduced density of pre- and postsynaptic markers. Similar early morphological modifications were also observed in cones and their related secondary neurons. However, cone function was maintained at nearly normal level for a long period. The dramatic loss of rods at late stage of degeneration may contribute to the dysfunction of cones. Attention has to be focused on preserving cone function and identifying factors that damage cones when therapeutic regimes are applied to treat retinal degeneration. As such, these findings provide a foundation for future studies involving treatments to counter photoreceptor loss. PMID:23510618

Lu, Bin; Morgans, Catherine W; Girman, Sergey; Lund, Raymond; Wang, Shaomei

2013-05-01

395

Retinal Biosynthesis in Fungi: Characterization of the Carotenoid Oxygenase CarX from Fusarium fujikuroi?  

PubMed Central

The car gene cluster of the ascomycete Fusarium fujikuroi encodes two enzymes responsible for torulene biosynthesis (CarRA and CarB), an opsin-like protein (CarO), and a putative carotenoid cleaving enzyme (CarX). It was presumed that CarX catalyzes the formation of the major carotenoid in F. fujikuroi, neurosporaxanthin, a cleavage product of torulene. However, targeted deletion of carX did not impede neurosporaxanthin biosynthesis. On the contrary, ?carX mutants showed a significant increase in the total carotenoid content, indicating an involvement of CarX in the regulation of the pathway. In this work, we investigated the enzymatic activity of CarX. The expression of the enzyme in ?-carotene-accumulating Escherichia coli cells led to the formation of the opsin chromophore retinal. The identity of the product was proven by high-performance liquid chromatography and gas chromatography-mass spectrometry. Subsequent in vitro assays with heterologously expressed and purified CarX confirmed its ?-carotene-cleaving activity and revealed its capability to produce retinal also from other substrates, such as ?-carotene, torulene, and ?-apo-8?-carotenal. Our data indicate that the occurrence of at least one ?-ionone ring in the substrate is required for the cleavage reaction and that the cleavage site is determined by the distance to the ?-ionone ring. CarX represents the first retinal-synthesizing enzyme reported in the fungal kingdom so far. It seems likely that the formed retinal is involved in the regulation of the carotenoid biosynthetic pathway via a negative feedback mechanism. PMID:17293483

Prado-Cabrero, Alfonso; Scherzinger, Daniel; Avalos, Javier; Al-Babili, Salim

2007-01-01

396

Action spectrum for melatonin regulation in humans: evidence for a novel circadian photoreceptor  

NASA Technical Reports Server (NTRS)

The photopigment in the human eye that transduces light for circadian and neuroendocrine regulation, is unknown. The aim of this study was to establish an action spectrum for light-induced melatonin suppression that could help elucidate the ocular photoreceptor system for regulating the human pineal gland. Subjects (37 females, 35 males, mean age of 24.5 +/- 0.3 years) were healthy and had normal color vision. Full-field, monochromatic light exposures took place between 2:00 and 3:30 A.M. while subjects' pupils were dilated. Blood samples collected before and after light exposures were quantified for melatonin. Each subject was tested with at least seven different irradiances of one wavelength with a minimum of 1 week between each nighttime exposure. Nighttime melatonin suppression tests (n = 627) were completed with wavelengths from 420 to 600 nm. The data were fit to eight univariant, sigmoidal fluence-response curves (R(2) = 0.81-0.95). The action spectrum constructed from these data fit an opsin template (R(2) = 0.91), which identifies 446-477 nm as the most potent wavelength region providing circadian input for regulating melatonin secretion. The results suggest that, in humans, a single photopigment may be primarily responsible for melatonin suppression, and its peak absorbance appears to be distinct from that of rod and cone cell photopigments for vision. The data also suggest that this new photopigment is retinaldehyde based. These findings suggest that there is a novel opsin photopigment in the human eye that mediates circadian photoreception.

Brainard, G. C.; Hanifin, J. P.; Greeson, J. M.; Byrne, B.; Glickman, G.; Gerner, E.; Rollag, M. D.

2001-01-01

397

Rhodopsin Mutant P23H Destabilizes Rod Photoreceptor Disk Membranes  

PubMed Central

Mutations in rhodopsin cause retinitis pigmentosa in humans and retinal degeneration in a multitude of other animals. We utilized high-resolution live imaging of the large rod photoreceptors from transgenic frogs (Xenopus) to compare the properties of fluorescently tagged rhodopsin, Rho-EGFP, and RhoP23H-EGFP. The mutant was abnormally distributed both in the inner and outer segments (OS), accumulating in the OS to a concentration of ?0.1% compared to endogenous opsin. RhoP23H-EGFP formed dense fluorescent foci, with concentrations of mutant protein up to ten times higher than other regions. Wild-type transgenic Rho-EGFP did not concentrate in OS foci when co-expressed in the same rod with RhoP23H-EGFP. Outer segment regions containing fluorescent foci were refractory to fluorescence recovery after photobleaching, while foci in the inner segment exhibited recovery kinetics similar to OS regions without foci and Rho-EGFP. The RhoP23H-EGFP foci were often in older, more distal OS disks. Electron micrographs of OS revealed abnormal disk membranes, with the regular disk bilayers broken into vesiculotubular structures. Furthermore, we observed similar OS disturbances in transgenic mice expressing RhoP23H, suggesting such structures are a general consequence of mutant expression. Together these results show that mutant opsin disrupts OS disks, destabilizing the outer segment possibly via the formation of aggregates. This may render rods susceptible to mechanical injury or compromise OS function, contributing to photoreceptor loss. PMID:22276148

Haeri, Mohammad; Knox, Barry E.

2012-01-01

398

Identification of the 11-cis-specific retinyl-ester synthase in retinal Müller cells as multifunctional O-acyltransferase (MFAT)  

PubMed Central

Absorption of a photon by a rhodopsin or cone-opsin pigment isomerizes its 11-cis-retinaldehyde (11-cis-RAL) chromophore to all-trans-retinaldehyde (all-trans-RAL), which dissociates after a brief period of activation. Light sensitivity is restored to the resulting apo-opsin when it recombines with another 11-cis-RAL. Conversion of all-trans-RAL to 11-cis-RAL is carried out by an enzyme pathway called the visual cycle in cells of the retinal pigment epithelium. A second visual cycle is present in Müller cells of the retina. The retinol isomerase for this noncanonical pathway is dihydroceramide desaturase (DES1), which catalyzes equilibrium isomerization of retinol. Because 11-cis-retinol (11-cis-ROL) constitutes only a small fraction of total retinols in an equilibrium mixture, a subsequent step involving selective removal of 11-cis-ROL is required to drive synthesis of 11-cis-retinoids for production of visual chromophore. Selective esterification of 11-cis-ROL is one possibility. Crude homogenates of chicken retinas rapidly convert all-trans-ROL to 11-cis-retinyl esters (11-cis-REs) with minimal formation of other retinyl-ester isomers. This enzymatic activity implies the existence of an 11-cis-specific retinyl-ester synthase in Müller cells. Here, we evaluated multifunctional O-acyltransferase (MFAT) as a candidate for this 11-cis-RE-synthase. MFAT exhibited much higher catalytic efficiency as a synthase of 11-cis-REs versus other retinyl-ester isomers. Further, we show that MFAT is expressed in Müller cells. Finally, homogenates of cells coexpressing DES1 and MFAT catalyzed the conversion of all-trans-ROL to 11-cis-RP, similar to what we observed with chicken-retina homogenates. MFAT is therefore an excellent candidate for the retinyl-ester synthase that cooperates with DES1 to drive synthesis of 11-cis-retinoids by mass action. PMID:24799687

Kaylor, Joanna J.; Cook,