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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

Ancestral loss of short wave-sensitive cone visual pigment in lorisiform prosimians, contrasting with its strict conservation in other prosimians.  

PubMed

Mammals are basically dichromatic in color vision, possessing middle to long wave-sensitive (M/LWS) and the short wave-sensitive (SWS) cone opsins in the retina, whereas some nocturnal mammals lack functional SWS opsins. Prosimians, primitive primates consisting of three extant groups (Lorisiformes, Lemuriformes, and Tarsiiformes), include many nocturnal species. Among nocturnal prosimians, a species of lorisiforms, the greater galago (Otolemur crassicaudatus), is known to lack a functional SWS opsin gene, while lemuriforms and tarsiiforms appear to retain SWS opsins in the retina. It has not been established, however, whether the loss of SWS opsin is a universal phenomenon among lorisiforms and whether the functional SWS opsin genes of lemuriforms and tarsiiforms are under strict or relaxed selective constraint. To gain better insight into an association between nocturnality and loss of SWS function, we isolated and sequenced the SWS opsin genes from two species of lorisiforms, the slow loris (Nycticebus coucang; nocturnal) and the lesser galago (Galago senegalensis; nocturnal), and one species each of lemuriforms and tarsiiforms, the brown lemur (Eulemur fulvus; cathemeral) and the western tarsier ( Tarsius bancanus; nocturnal), respectively. Our sequence analysis revealed that (1) the SWS opsin gene was disrupted in the common ancestor of galagids and lorisids and (2) the rate of nonsynonymous nucleotide substitution has been kept significantly lower than that of synonymous substitution in tarsier and lemur, demonstrating the presence of strict selective constraint on the SWS opsin genes in tarsiiforms and lemuriforms. PMID:15045486

Kawamura, Shoji; Kubotera, Naoya

2004-03-01

4

Opsin gene duplication and diversification in the guppy, a model for sexual selection.  

PubMed

Identification of genes that control variation in adaptive characters is a prerequisite for understanding the processes that drive sexual and natural selection. Male coloration and female colour perception play important roles in mate choice in the guppy (Poecilia reticulata), a model organism for studies of natural and sexual selection. We examined a potential source for the known variation in colour perception, by analysing genomic and complementary DNA sequences of genes that code for visual pigment proteins. We find high sequence variability, both within and between populations, and expanded copy number for long-wave sensitive (LWS) opsin genes. Alleles with non-synonymous changes that suggest dissimilar spectral tuning properties occur in the same population and even in the same individual, and the high frequency of non-synonymous substitutions argues for diversifying selection acting on these proteins. Therefore, variability in tuning amino acids is partitioned within individuals and populations of the guppy, in contrast to variability for LWS at higher taxonomic levels in cichlids, a second model system for differentiation owing to sexual selection. Since opsin variability parallels the extreme male colour polymorphism within guppy populations, we suggest that mate choice has been a major factor driving the coevolution of opsins and male ornaments in this species. PMID:17015333

Hoffmann, Margarete; Tripathi, Namita; Henz, Stefan R; Lindholm, Anna K; Weigel, Detlef; Breden, Felix; Dreyer, Christine

2007-01-01

5

Gene duplication and divergence of long wavelength-sensitive opsin genes in the guppy, Poecilia reticulata.  

PubMed

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 (MSP). However, the relationship between LWS genomic repertoires and expression of LWS retinal cone classes within a given species is unclear. Our previous study in the related species, Xiphophorus helleri, was the first characterization of the complete LWS opsin genomic repertoire in conjunction with MSP expression data in the family Poeciliidae, and revealed the presence of four LWS loci and two distinct LWS cone classes. In this study we characterized the genomic organization of LWS opsin genes by BAC clone sequencing, and described the full range of cone cell types in the retina of the colorful Cumaná guppy, Poecilia reticulata. In contrast to X. helleri, MSP data from the Cumaná guppy revealed three LWS cone classes. Comparisons of LWS genomic organization described here for Cumaná to that of X. helleri indicate that gene divergence and not duplication was responsible for the evolution of a novel LWS haplotype in the Cumaná guppy. This lineage-specific divergence is likely responsible for a third additional retinal cone class not present in X. helleri, and may have facilitated the strong sexual selection driven by female preference for orange color patterns associated with the genus Poecilia. PMID:21170644

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

2010-12-18

6

Long-wavelength sensitive visual pigments of the guppy (Poecilia reticulata): six opsins expressed in a single individual  

PubMed Central

Background The diversity of visual systems in fish has long been of interest for evolutionary biologists and neurophysiologists, and has recently begun to attract the attention of molecular evolutionary geneticists. Several recent studies on the copy number and genomic organization of visual pigment proteins, the opsins, have revealed an increased opsin diversity in fish relative to most vertebrates, brought about through recent instances of opsin duplication and divergence. However, for the subfamily of opsin genes that mediate vision at the long-wavelength end of the spectrum, the LWS opsins, it appears that most fishes possess only one or two loci, a value comparable to most other vertebrates. Here, we characterize the LWS opsins from cDNA of an individual guppy, Poecilia reticulata, a fish that is known exhibit variation in its long-wavelength sensitive visual system, mate preferences and colour patterns. Results We identified six LWS opsins expressed within a single individual. Phylogenetic analysis revealed that these opsins descend from duplication events both pre-dating and following the divergence of the guppy lineage from that of the bluefin killifish, Lucania goodei, the closest species for which comparable data exists. Numerous amino acid substitutions exist among these different LWS opsins, many at sites known to be important for visual pigment function, including spectral sensitivity and G-protein activation. Likelihood analyses using codon-based models of evolution reveal significant changes in selective constraint along two of the guppy LWS opsin lineages. Conclusion The guppy displays an unusually high number of LWS opsins compared to other fish, and to vertebrates in general. Observing both substitutions at functionally important sites and the persistence of lineages across species boundaries suggests that these opsins might have functionally different roles, especially with regard to G-protein activation. The reasons why are currently unknown, but may relate to aspects of the guppy's behavioural ecology, in which both male colour patterns and the female mate preferences for these colour patterns experience strong, highly variable selection pressures.

Weadick, Cameron J; Chang, Belinda SW

2007-01-01

7

Adaptation of visual spectra and opsin genes in seabreams.  

PubMed

Three species of seabreams, Acanthopagrus berda, Acanthopagrus schlegelii and Pagrus major, living at different depths, were chosen to investigate how visual spectra and opsin genes evolve in response to various photic environments. The lambda max of photoreceptors and opsin genes were measured and cloned from these species. Eight to twelve nm spectral shifts in the rod and blue cone cells were observed between the deep-sea, P. major, and shallow-sea species, A. berda and A. schlegelii. Furthermore, the deep-sea P. major has lost its red light vision. Six opsin genes, Rh1, Rh2A, Rh2B, SWS1, SWS2 and LWS, were identified from all three seabream species, with the LWS genes of P. major having undergone pseudogenization. These data indicate that the photic environment of habitats select for the physiology of visual spectra and coding of opsin genes. PMID:19422842

Wang, Feng Yu; Yan, Hong Young; Chen, Johnny Shou-Chung; Wang, Tzi Yuan; Wang, Daryi

2009-05-05

8

Molecular cloning and expression of long-wavelength-sensitive cone opsin in the brain of a tropical damselfish.  

PubMed

Ovarian development of the sapphire devil, Chrysiptera cyanea, exhibits photoperiodism and is stimulated under long-day conditions. Previous studies suggest that red light is more effective than green and blue lights for inducing ovarian development. In addition, the extra-retinal photoreception involved in the ovarian development is suggested in this species. The present study aimed to clone the red-light-sensitive cone opsin (sdLWS) of this species, to demonstrate its expression in the brain, and to confirm the effectiveness of red light on the initiation of ovarian development. A phylogenetic analysis revealed that sdLWS belongs to the long-wavelength-sensitive opsin (LWS opsin) group, showing high identity (77-92%) with the LWS opsin of other fishes. RT-PCR showed that sdLWS is expressed in the eye, brain, and ovary. In situ hybridization indicated that sdLWS is expressed in the third ventricle periventricular area in the anterior hypothalamus. Exposing fish to long-day conditions of red light resulted in the appearance of vitellogenic oocytes in the ovary and an increase in the gonadosomatic index within 2weeks, suggesting that fish immediately undergo oocyte development under red light conditions. These results indicate that sdLWS is a possible candidate of deep brain photoreceptor molecule involved in photoperiodic ovarian development in the sapphire devil. PMID:21871576

Takeuchi, Yuki; Bapary, Mohammad Abu Jafor; Igarashi, Syugo; Imamura, Satoshi; Sawada, Yuji; Matsumoto, Mio; Hur, Sung-Pyo; Takemura, Akihiro

2011-08-16

9

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.

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

2009-01-01

10

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

11

Catalogue of ISO LWS observations of asteroids  

NASA Astrophysics Data System (ADS)

Context: The long wavelength spectrometer (LWS) onboard the infrared space observatory (ISO) observed the four large main-belt asteroids (1) Ceres, (2) Pallas, (4) Vesta, and (10) Hygiea multiple times. The photometric and spectroscopic data cover the wavelength range between 43 and 197 ?m, and are a unique dataset for future investigations and detailed characterisations of these bodies. Aims: The standard ISO archive products, produced through the last post-mission LWS pipeline, were still affected by instrument artefacts. Our goal was to provide the best possible data products to exploit the full scientific potential of these observations. Methods: For all asteroid observations we analysed in detail the dark current, the calibration reference flashes, the space environment effects (glitches), memory effects, tracking influences, and various other sources of uncertainty. We performed a refined reduction of all measurements, corrected for the various effects, and re-calibrated the data. We outline the data reduction process and give an overview of the available data and the quality of the observations. We apply a thermophysical model to the flux measurements to derive far-IR based diameter and albedo values of the asteroids. The measured thermal rotational lightcurve of (4) Vesta is compared to model predictions. Results: The catalogue of LWS (long wavelength spectrometer) observations of asteroids contains 57 manually reduced datasets, including seven non-standard observations, which as such did not have final pipeline products available before. In total, the archive now contains 11 spectral scans and 46 fixed grating measurements with a simultaneous observation at 10 key wavelengths distributed over the full LWS range. The new data products are now accessible via the ISO data archive as highly processed data products (HPDP). Conclusions: The quality of the data products was checked against state-of-the-art thermophysical model predictions and an excellent agreement was found. The absolute photometric accuracy is better than 10%. The calibrated spectra will serve as a source for future mineralogical studies of dwarf planets and dwarf planet candidates. Based on observations with ISO, an ESA project with instruments funded by ESA Member States (especially the PI countries: France, Germany, the Netherlands and the UK) and with the participation of ISAS and NASA.

Hormuth, F.; Müller, T. G.

2009-04-01

12

ISO LWS Spectroscopy of NGC 4945  

NASA Astrophysics Data System (ADS)

We have obtained fully sampled, low resolution (R=lambda / triangle lambda ~ 200) far-infrared (FIR) 42-197 mu m spectra of the southern AGN/starburst SB(s)cd galaxy NGC 4945 with the Long Wavelength Spectrometer (LWS) on the Infrared Space Observatory (ISO). The galaxy was observed at a central, NE, and SW position, each separated by 165'' with the instrument's ~ 75" aperture. The forbidden fine-structure transitions of [CII] 158 mu m and [OI] 63 mu m lines were detected at each position. Detections of the [OI] 145 mu m and [OIII] 88 mu m lines were also obtained at some positions. Using these lines and the total FIR continuum flux, we have modeled the properties of the warm atomic gas with photodissociation region (PDR) models (Tielens and Hollenbach, 1985; Wolfire et al. 1990; Kaufman et al. 1998). The low-J rotational transitions of OH at 53 mu m and 119 mu m are seen in absorption at the nuclear position. The total OH column density and the role of these lines in the pumping of the OH radio maser are considered for these two transitions. The NE and SW positions lie on the massive molecular ring. The ring versus the nuclear conditions are analyzed by comparing the CII/OI, CII/CO, and (CII+OI)/FIR ratios.

Brauher, J.; Lord, S.; Unger, S.; Wolfire, M.; Fischer, J.

1997-12-01

13

Opsin is a phospholipid flippase  

PubMed Central

Summary Polar lipids must flip-flop rapidly across biological membranes to sustain cellular life [1, 2], but flipping is energetically costly [3] and it’s intrinsic rate is low. To overcome this problem, cells have membrane proteins that function as lipid transporters (flippases) to accelerate flipping to a physiologically relevant rate. Flippases that operate at the plasma membrane of eukaryotes, coupling ATP hydrolysis to unidirectional lipid flipping, have been defined at a molecular level [2]. On the other hand, ATP-independent bidirectional flippases that translocate lipids in biogenic compartments, e.g., the endoplasmic reticulum, and specialized membranes, e.g., photoreceptor discs [4, 5], have not been identified even though their activity has been recognized for more than 30 years [1]. Here we demonstrate that opsin is the ATP-independent phospholipid flippase of photoreceptor discs. We show that reconstitution of opsin into large unilamellar vesicles promotes rapid (? <10 sec) flipping of phospholipid probes across the vesicle membrane. This is the first molecular identification of an ATP-independent phospholipid flippase in any system. It reveals an unexpected activity for opsin and, in conjunction with recently available structural information on this G-protein coupled receptor [6, 7], significantly advances our understanding of the mechanism of ATP-independent lipid flip-flop.

Menon, Indu; Huber, Thomas; Sanyal, Sumana; Banerjee, Sourabh; Barre, Patrick; Canis, Sam; Warren, J. David; Hwa, John; Sakmar, Thomas P.; Menon, Anant K.

2010-01-01

14

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

15

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

16

Human scotopic dark adaptation: Comparison of recoveries of psychophysical threshold and ERG b-wave sensitivity.  

PubMed

We have compared the time course of dark adaptation of the human scotopic visual system, measured psychophysically and from the b-wave of the electroretinogram (ERG), for bleaches ranging from a few percent to near total. We also measured light adaptation, in order to apply a "Crawford transformation" to convert the raw measurements of dark adaptation into equivalent background intensities. For both the "psychophysical threshold equivalent" intensity and the "ERG b-wave sensitivity equivalent" intensity, the equivalent background declined over much of its range with an "S2" component, though with somewhat different slopes of -0.36 (psychophysical) and -0.22 (ERG) log(10) unit min(-1), respectively. In addition, the magnitude of the equivalent background was approximately 1 log(10) unit lower in the psychophysical experiments than in the ERG experiments. Despite these differences, the two approaches extract a common time course for the decline in level of free opsin following moderately large bleaches. We conclude that the recovery of psychophysical scotopic visual threshold over the S2 region reflects events that are present by the stage of the first synapse of rod vision, stemming ultimately from the presence of unregenerated opsin in the rod outer segments. PMID:21733908

Ruseckaite, Rasa; Lamb, Trevor D; Pianta, Michael J; Cameron, Allison M

2011-07-06

17

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

2012-10-29

18

C-opsin expressing photoreceptors in echinoderms.  

PubMed

Today's progress in molecular analysis and, in particular, the increased availability of genome sequences have enabled us to investigate photoreceptor cells (PRCs) in organisms that were formerly inaccessible to experimental manipulation. Our studies of marine non-chordate deuterostomes thus aim to bridge a gap of knowledge regarding the evolution of deuterostome PRCs prior to the emergence of vertebrates' eyes. In this contribution, we will show evidence for expression of a c-opsin photopigment, which, according to our phylogenetic analysis, is closely related to an assemblage of chordate visual c-opsins. An antibody raised against sea urchins' c-opsin protein (Sp-Opsin1) recognizes epitopes in a variety of tissues of different echinoderms. While in sea urchins this c-opsin is expressed in locomotory and buccal tube feet, spines, pedicellaria, and epidermis, in brittlestars and starfish we found the immuno-reaction to be located exclusively in cells within the animals' spines. Structural characteristics of these c-opsin+ PRC types include the close vicinity/connection to nerve strands and a, so far unexplored, conspicuous association with the animals' calcite skeleton, which previously has been hypothesized to play a role in echinoderm photobiology. These features are discussed within the context of the evolution of photoreceptors in echinoderms and in deuterostomes generally. PMID:23667044

Ullrich-Lüter, Esther M; D'Aniello, Salvatore; Arnone, Maria I

2013-05-10

19

ISO LWS measurement of the far-infrared spectrum of Saturn  

Microsoft Academic Search

The spectrum of Saturn from 43 to 197mum was measured with the ISO Long Wavelength Spectrometer (LWS) during the performance verification phase of the mission. The measurements were made using the LWS in grating mode, with spectral resolutions of 0.29mum from 43 to 90mum and 0.6mum from 90 to 197mum. The spectrum was compared with an atmospheric radiative-transfer model and

G. R. Davis; M. J. Griffin; D. A. Naylor; P. G. Oldham; B. M. Swinyard; P. A. R. Ade; S. B. Calcutt; T. Encrenaz; T. de Graauw; D. Gautier; P. G. J. Irwin; E. Lellouch; G. S. Orton; C. Armand; M. Burgdorf; A. di Giorgio; D. Ewart; C. Gry; K. J. King; T. Lim; S. Molinari; M. Price; S. Sidher; A. Smith; D. Texier; N. Trams; S. J. Unger

1996-01-01

20

Opsin, a structural model for olfactory receptors?  

PubMed

Receptor-ligand interaction: Olfactory receptors (ORs) are G-protein-coupled receptors (GPCRs), which detect signaling molecules such as hormones and odorants. The structure of opsin, the GPCR employed in vision, with a detergent molecule bound deep in its orthosteric ligand-binding pocket provides a template for OR homology modeling, thus enabling investigation of the structural basis of the mechanism of odorant-receptor recognition. PMID:24038729

Park, Jung Hee; Morizumi, Takefumi; Li, Yafang; Hong, Joo Eun; Pai, Emil F; Hofmann, Klaus Peter; Choe, Hui-Woog; Ernst, Oliver P

2013-08-26

21

Thyroid hormone accelerates opsin expression during early photoreceptor differentiation and induces opsin switching in differentiated TR?-expressing cones of the salmonid retina.  

PubMed

Thyroid hormone and its receptors (TRs) regulate photoreceptor differentiation and visual pigment protein (opsin) expression in the retinas of several vertebrates, including rodents and fish. In some of these animals, opsin expression can arise through switches within differentiated cone photoreceptors. In salmonid fishes, single cones express ultraviolet (SWS1) opsin during embryonic development and switch to blue (SWS2) opsin as the fishes grow. It is unknown whether thyroid hormone regulates opsin expression during early cone differentiation and acts through TRs to induce opsin switches in differentiated cones of the salmonid retina. Using in situ hybridization, we characterized the spatiotemporal dynamics of opsin expression and switching in embryos treated with exogenous thyroid hormone or propylthiouracil (PTU), a pharmacological inhibitor of thyroid hormone synthesis. We combined immunohistochemistry with in situ hybridization to map TR? expression with respect to cones undergoing the opsin switch in older juvenile fish. Thyroid hormone accelerated opsin expression in differentiating cones and induced the opsin switch in differentiated single cones, whereas PTU repressed the opsin switch. TR? was not detected in differentiating photoreceptors as opsin expression initiated, but was later expressed in differentiated single cones before the onset of the opsin switch. TR? expression exhibited a dynamic dorsoventral distribution that paralleled the progression of the opsin switch. Together, our results show that thyroid hormone is required for opsin switching in the retina of salmonid fishes and suggest that TR? may be involved in regulating this phenomenon. PMID:20730870

Gan, Kathlyn J; Novales Flamarique, Iñigo

2010-10-01

22

LWS spectroscopy of the luminous blue compact galaxy Haro 11  

NASA Astrophysics Data System (ADS)

We present the results of far infrared (FIR) spectroscopy of the luminous blue compact galaxy (BCG) Haro 11 (ESO 350-IG38) obtained with the Long Wavelength Spectrometer (LWS) on the Infrared Space Observatory (ISO) in low resolution mode. This metal poor dwarf merger is an extremely hot IRAS source. We discuss the balance between dust and line cooling in the photodissociated regions (PDR), in particular the role of the [CII]?158 ? line, and derive the basic properties of the PDR gas and estimates of the gas and dust masses. The mass of the PDRs, 2+2-1 108 M\\odota, is comparable to that of the ionized gas and exceeds the observed upper limit of the HI mass. The gas/dust mass ratio is low, indicating that the galaxy contains little cold dust. The low metallicity, the intense radiation field and the low column density of Haro 11 results in an extremely high [CII]/CO flux ratio and probably also a very high M (H2)/LCO conversion factor. Therefore CO is a poor indicator of the H2 mass in starburst dwarf galaxies. After a reanalysis we confirm the claimed correlation (Malhotra et al. cite {malhotra}) between the [CII]158 ?/FIR flux ratio and the IRAS f60/f100 dust temperature and reduce the scatter. We find that Haro 11 deviates from the relationship being brighter in [CII] than what would be expected, if the mechanism proposed by Malhotra et al. is dominant. As an alternative (or complementary) explanation we propose that the [CII]158 ?/FIR versus f60/f100 relationship is caused by an increasing optical depth with increasing IRAS temperature. The low metallicity of Haro 11 and its extreme starburst properties probably allows the medium to be thin despite its high f60/f100 ratio. This leaves room for a more optimistic view on the possibilities to detect massive starforming mergers at high redshifts, using the [CII] line. Based on observations with ISO, an ESA project with instruments funded by ESA Member States (especially the PI countries: France, Germany, the Netherlands and the United Kingdom) with the participation of ISAS and NASA.

Bergvall, N.; Masegosa, J.; Östlin, G.; Cernicharo, J.

2000-07-01

23

Studies of star formation with the LWS: calibration of strong sources.  

NASA Astrophysics Data System (ADS)

The Long-Wavelength Spectrometer (LWS) is one of four instruments of the Infrared Space Observatory (ISO). The LWS Consortium has an wide-ranging programme of observations which are being carried out in its share of observing time, including the study of the interstellar medium and star formation. Some of these sources are so strong that the usual method of processing the data fails. The authors describe the reduction and calibration of these data, illustrating the process with the W28 A2, a strong molecular outflow source.

Leeks, S. J.; Clegg, P. E.; Saraceno, P.

24

Molecular Characterization of Crustacean Visual Pigments and the Evolution of Pancrustacean Opsins  

Microsoft Academic Search

Investigations of opsin evolution outside of vertebrate systems have long been focused on insect visual pigments, whereas other groups have received little attention. Furthermore, few studies have explicitly investigated the selective influences across all the currently characterized arthropod opsins. In this study, we contribute to the knowledge of crustacean opsins by sequencing 1 opsin gene each from 6 previously uncharacterized

Megan L. Porter; Thomas W. Cronin; David A. McClellan; Keith A. Crandall

2006-01-01

25

Implications of the ISO LWS Spectrum of the Prototypical Ultraluminous Galaxy: ARP 220.  

National Technical Information Service (NTIS)

We present a low resolution (R =lamba / Delta lamba200) far- infrared (43-197 micrometer) spectrum of the ultraluminous galaxy Arp 220, obtained from deep full-range scans using the Long Wavelength Spectrometer (LWS) aboard the Infrared Space Observatory ...

G. Melnick J. Fischer M. L. Luhman P. Cox S. Satyapal

1997-01-01

26

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

National Technical Information Service (NTIS)

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,...

R. Patschke J. Barth K. Label C. Mariano K. Pham D. Brewer M. Cuviello D. Kobe C. Wu D. Jarosz

2004-01-01

27

[Pathology of opsins and vision disorders].  

PubMed

Mutations of the gene encoding rhodopsin are responsible for 30% of the cases autosomal dominant retinitis pigmentosa. Rhodopsin molecules are key G-coupled transmembrane proteins initiating the visual transduction cascade in rods. These cells are specialized retinal cells allowing the detection of low intensity lights. Mutations in the rhodopsin gene lead to the progressive destruction of rods, clinically translated by night blindness, a progressive bilateral loss of the peripheral visual field, and predominant alterations of the rod component of the electroretinograms. Inherited colour vision deficiencies are mainly caused by alterations of the genes encoding coloured opsins. These proteins are G-coupled receptors specialized in visual transduction in the cones. These sensorial cells are localized in the center of the neural retina where they allow the detection of refined details and chromatic lights. Rearrangements of the genes encoding the green and the red color pigments are responsible for daltonism. PMID:7939339

Abitbol, M; Eppelbaum, M; Dolfuss, H; Dufier, J L

1994-05-01

28

Evolutionary Diversification of Visual Opsin Genes in Fish and Primates  

Microsoft Academic Search

\\u000a Among vertebrates, fish and primates are highly polymorphic in their color vision. This diversity likely reflects the variability\\u000a in light environments inhabited by these species. Gene duplications and allelic differentiation of opsin genes play an important\\u000a role in the evolution of color vision in fish and primates. Studies have shown that gene duplications of opsins have occurred\\u000a repeatedly during fish

Shoji Kawamura

29

Opsin co-expression in Limulus photoreceptors: differential regulation by light and a circadian clock  

PubMed Central

A long-standing concept in vision science has held that a single photoreceptor expresses a single type of opsin, the protein component of visual pigment. However, the number of examples in the literature of photoreceptors from vertebrates and invertebrates that break this rule is increasing. Here, we describe a newly discovered Limulus opsin, Limulus opsin5, which is significantly different from previously characterized Limulus opsins, opsins1 and 2. We show that opsin5 is co-expressed with opsins1 and 2 in Limulus lateral and ventral eye photoreceptors and provide the first evidence that the expression of co-expressed opsins can be differentially regulated. We show that the relative levels of opsin5 and opsin1 and 2 in the rhabdom change with a diurnal rhythm and that their relative levels are also influenced by the animal's central circadian clock. An analysis of the sequence of opsin5 suggests it is sensitive to visible light (400–700 nm) but that its spectral properties may be different from that of opsins1 and 2. Changes in the relative levels of these opsins may underlie some of the dramatic day–night changes in Limulus photoreceptor function and may produce a diurnal change in their spectral sensitivity.

Katti, C.; Kempler, K.; Porter, M. L.; Legg, A.; Gonzalez, R.; Garcia-Rivera, E.; Dugger, D.; Battelle, B.-A.

2010-01-01

30

Ant opsins: sequences from the Saharan silver ant and the carpenter ant.  

PubMed

cDNA clones encoding opsins from compound eyes of carpenter ant, Camponotus abdominalis, and Saharan silver ant, Cataglyphis bombycina, were isolated from cDNA libraries. The opsin cDNAs from each species code for deduced proteins with 378 amino acids which are 92% identical. Of the 30 amino acid differences between the two proteins, 13 are non-conservative. Eight of these non-conservative substitutions are within the membrane spanning domain. The presence of a potential Schiff-base counterion in helix III in both species suggests that these opsins are the protein moiety of the visible range pigments. When compared to all known opsins, these opsins are most similar to the opsin from preying mantis (76% identity at the amino acid level). Phyletic comparisons group the two ant opsins with the other arthropod long wavelength opsins. PMID:9372150

Popp, M P; Grisshammer, R; Hargrave, P A; Smith, W C

1996-03-01

31

In silico characterisation and chromosomal localisation of human RRH (peropsin) - implications for opsin evolution  

Microsoft Academic Search

Background  The vertebrate opsins are proteins which utilise a retinaldehyde chromophore in their photosensory or photoisomerase roles\\u000a in the visual\\/irradiance detection cycle. The majority of the opsins, such as rod and cone opsins, have a very highly conserved\\u000a gene structure suggesting a common lineage. Exceptions to this are RGR-opsin and melanopsin, whose genes have very different\\u000a intron insertion positions. The gene

James Bellingham; Dominic J Wells; Russell G Foster

2003-01-01

32

Reduced opsin gene expression in a cave-dwelling fish  

PubMed Central

Regressive evolution of structures associated with vision in cave-dwelling organisms is the focus of intense research. Most work has focused on differences between extreme visual phenotypes: sighted, surface animals and their completely blind, cave-dwelling counterparts. We suggest that troglodytic systems, comprising multiple populations that vary along a gradient of visual function, may prove critical in understanding the mechanisms underlying initial regression in visual pathways. Gene expression assays of natural and laboratory-reared populations of the Atlantic molly (Poecilia mexicana) revealed reduced opsin expression in cave-dwelling populations compared with surface-dwelling conspecifics. Our results suggest that the reduction in opsin expression in cave-dwelling populations is not phenotypically plastic but reflects a hardwired system not rescued by exposure to light during retinal ontogeny. Changes in opsin gene expression may consequently represent a first evolutionary step in the regression of eyes in cave organisms.

Tobler, Michael; Coleman, Seth W.; Perkins, Brian D.; Rosenthal, Gil G.

2010-01-01

33

Variations in Opsin Coding Sequences Cause X-Linked Cone Dysfunction Syndrome with Myopia and Dichromacy  

PubMed Central

Purpose. To determine the role of variant L opsin haplotypes in seven families with Bornholm Eye Disease (BED), a cone dysfunction syndrome with dichromacy and myopia. Methods. Analysis of the opsin genes within the L/M opsin array at Xq28 included cloning and sequencing of an exon 3-5 gene fragment, long range PCR to establish gene order, and quantitative PCR to establish gene copy number. In vitro expression of normal and variant opsins was performed to examine cellular trafficking and spectral sensitivity of pigments. Results. All except one of the BED families possessed L opsin genes that contained a rare exon 3 haplotype. The exception was a family with the deleterious Cys203Arg substitution. Two rare exon 3 haplotypes were found and, where determined, these variant opsin genes were in the first position in the array. In vitro expression in transfected cultured neuronal cells showed that the variant opsins formed functional pigments, which trafficked to the cell membranes. The variant opsins were, however, less stable than wild type. Conclusions. It is concluded that the variant L opsin haplotypes underlie BED. The reduction in the amount of variant opsin produced in vitro compared with wild type indicates a possible disease mechanism. Alternatively, the recently identified defective splicing of exon 3 of the variant opsin transcript may be involved. Both mechanisms explain the presence of dichromacy and cone dystrophy. Abnormal pigment may also underlie the myopia that is invariably present in BED subjects.

McClements, Michelle; Davies, Wayne I. L.; Michaelides, Michel; Young, Terri; Neitz, Maureen; MacLaren, Robert E.; Moore, Anthony T.; Hunt, David M.

2013-01-01

34

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.

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

35

Expression dynamics and protein localization of rhabdomeric opsins in platynereis larvae.  

PubMed

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

2013-05-10

36

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.

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

2007-01-01

37

Molecular evolution of arthropod color vision deduced from multiple opsin genes of jumping spiders.  

PubMed

Among terrestrial animals, only vertebrates and arthropods possess wavelength-discrimination ability, so-called "color vision". For color vision to exist, multiple opsins which encode visual pigments sensitive to different wavelengths of light are required. While the molecular evolution of opsins in vertebrates has been well investigated, that in arthropods remains to be elucidated. This is mainly due to poor information about the opsin genes of non-insect arthropods. To obtain an overview of the evolution of color vision in Arthropoda, we isolated three kinds of opsins, Rh1, Rh2, and Rh3, from two jumping spider species, Hasarius adansoni and Plexippus paykulli. These spiders belong to Chelicerata, one of the most distant groups from Hexapoda (insects), and have color vision as do insects. Phylogenetic analyses of jumping spider opsins revealed a birth and death process of color vision evolution in the arthropod lineage. Phylogenetic positions of jumping spider opsins revealed that at least three opsins had already existed before the Chelicerata-Pancrustacea split. In addition, sequence comparison between jumping spider Rh3 and the shorter wavelength-sensitive opsins of insects predicted that an opsin of the ancestral arthropod had the lysine residue responsible for UV sensitivity. These results strongly suggest that the ancestral arthropod had at least trichromatic vision with a UV pigment and two visible pigments. Thereafter, in each pancrustacean and chelicerate lineage, the opsin repertoire was reconstructed by gene losses, gene duplications, and function-altering amino acid substitutions, leading to evolution of color vision. PMID:18217181

Koyanagi, Mitsumasa; Nagata, Takashi; Katoh, Kazutaka; Yamashita, Shigeki; Tokunaga, Fumio

2008-01-24

38

The ISO-LWS map of the Serpens cloud core. II. The line spectra  

NASA Astrophysics Data System (ADS)

We present spectrophotometric ISO imaging with the LWS and the CAM-CVF of the Serpens molecular cloud core. The LWS map is centred on the far infrared and submillimetre source FIRS 1/SMM 1 and its size is 8',x 8'. The fine structure line emission in [O I] 63 mu m and [C II] 157 mu m is extended on the arcminute scale and can be successfully modelled to originate in a PDR with G0 = 15 +/- 10 and n(H2) in the range of (104-105) cm-3. Extended emission might also be observed in the rotational line emission of H2O and high-J CO. However, lack of sufficient angular resolution prevents us from excluding the possibility that the emssion regions of these lines are point like, which could be linked to the embedded objects SMM 9/S 68 and SMM 4. Toward the Class 0 source SMM 1, the LWS observations reveal, in addition to fine structure line emission, a rich spectrum of molecular lines, superposed onto a strong, optically thick dust continuum (Larsson et al. \\cite{Lar00}). The sub-thermally excited and optically thick CO, H2O and OH lines are tracing an about 103 AU source with temperatures higher than 300 K and densities above 106 cm-3 (M=0.01 Msun). The molecular abundances, X=N(mol)/N(H2), are X=(1, 0.1, 0.02, ge 0.025) x 10-4 for CO, H2O, OH and 13CO, respectively. Our data are consistent with an ortho-to-para ratio of 3 for H2O. OH appears highly overabundant, which we tentatively ascribe to an enhanced (X-ray) ionisation rate in the Serpens cloud core (zeta >> 10-18 s-1). We show that geometry is of concern for the correct interpretation of the data and based on 2D-radiative transfer modelling of the disk/torus around SMM 1, which successfully reproduces the entire observed SED and the observed line profiles of low-to-mid-J CO isotopomers, we can exclude the disk to be the source of the LWS-molecular line emission. The same conclusion applies to models of dynamical collapse (``inside-out'' infall). The 6{' '} pixel resolution of the CAM-CVF permits us to see that the region of rotational H2 emission is offset from SMM 1 by 30{' '}, at position angle 340deg, which is along the known jet flow from the Class 0 object. This H2 gas is extinguished by AV = 4.5 mag and at a temperature of 10310 K, which suggests that the heating of the gas is achieved through relatively slow shocks. Although we are not able to establish any firm conclusion regarding the detailed nature of the shock waves, our observations of the molecular line emission from SMM 1 are to a limited extent explainable in terms of an admixture of J-shocks and of C-shocks, the latter with speeds of about (15-20) km s-1, whereas dynamical infall is not directly revealed by our data. Based on observations with ISO, an ESA project with instruments funded by ESA Member States (especially the PI countries: France, Germany, The Netherlands and the UK) and with the participation of ISAS and NASA.

Larsson, B.; Liseau, R.; Men'shchikov, A. B.

2002-05-01

39

Demonstration of a Prototype Magnetospheric State-Based Trapped Radiation Data Base for the LWS Program  

NASA Astrophysics Data System (ADS)

A prototype magnetospheric state-based trapped radiation data base has been constructed as part of a proof-of-concept implementation of a new-generation trapped radiation model. Trapped radiation data from the data base, itself consisting of a data base of magnetospheric state (Psi) parameters and a data base of particle measurements (Phi), can be queried by specifying a set of magnetospheric-state (MS) parameters or a MS vector, as proposed by Fung [1996]. Trapped particle data having the same MS can then be retrieved from the data base and used to construct a trapped radiation model for the given MS condition. In this presentation, we demonstrate the capabilities of the prototype data base and discuss their implications for the LWS program. Fung, S. F., Recent development in the NASA trapped radiation models, Radiation belts Models and Standards, Geophysical Monogr., 97, AGU, Washington, D. C., 79-91, 1996.

Fung, S. F.; Shao, X.; Bell, E. V.; Tan, L. C.; McGuire, R. E.; Candey, R. M.; Huston, S. L.; Golightly, M. J.

2003-12-01

40

Characterisation of the ultraviolet-sensitive opsin gene in the honey bee, Apis mellifera.  

PubMed

The cDNA sequence of the ultraviolet-sensitive opsin in the honey-bee, Apis mellifera, with associated 5' and 3' untranslated regions, is presented. The analysis of genomic structure reveals seven introns in the coding region of the gene, with six at novel positions for an insect opsin gene. The equivalent site to the counterion in vertebrate opsins is occupied by a Tyr residue. This contrasts with the presence of Phe at this site in the ultraviolet-sensitive opsins of Drosophila sps. A comparison of the amino acid sequence within the seven alpha-helical transmembrane regions of insect ultraviolet/blue-sensitive opsins identifies substitution at five sites that involve either replacement of a polar with a non-polar residue, or a change in charge. Such changes are known to result in spectral shifts in vertebrate pigments. Phylogenetic analysis indicates that the ultraviolet-sensitive pigments represent an ancient class of insect opsins. PMID:9057845

Bellingham, J; Wilkie, S E; Morris, A G; Bowmaker, J K; Hunt, D M

1997-02-01

41

ISO-LWS observations of Herbig Ae/Be stars. I. Fine structure lines  

NASA Astrophysics Data System (ADS)

We present the results of the first spectrophotometric survey of a sample of eleven Herbig Ae/Be stars (HAEBE) obtained with the Long Wavelength Spectrometer (LWS) on board the Infrared Space Observatory (ISO). The [OI] 63mu m and the [CII] 158mu m lines are observed in all the investigated sources, while the [OI] 145mu m transition, due to its relative faintness, sometimes remains undetected. By comparing line intensity ratios with model predictions, photodissociation, due to the UV photons from the central star, results the dominating excitation mechanism although contributions of C-shocks to the [OI] emission cannot be ruled out. A clear example for the presence of a photodissociation region (PDR) illuminated by an HAEBE is shown by LWS spectroscopic mapping of NGC 7129. Some diagnostic probes of the radiation field and density are provided for the objects in our sample: these substantially agree with the known characteristics of both the star and its circumstellar environment, although the observed ratio [OI]63/[OI]145 tends to be smaller than predicted by PDR models. The most likely explanation for this behaviour is self-absorption at 63mu m by cold atomic oxygen. Fine structure lines of the ionised species [OIII], [NII] were detected whenever the star had a spectral type of B0 or earlier; in particular, around the star CoD-42(deg) 11721, besides a compact HII region, evidence is given for an extended low electron density ionised region. Finally, molecular line emission is associated with stars powering a CO outflow, and clumpy PDR models, better than C-shock models, predict for them relative cooling (CO vs OI and CO vs OH) similar to the observed ones. Based on observations with ISO, an ESA project with instruments funded by ESA Member States and with the participation of ISAS and NASA}

Lorenzetti, D.; Tommasi, E.; Giannini, T.; Nisini, B.; Benedettini, M.; Pezzuto, S.; Strafella, F.; Barlow, M.; Clegg, P. E.; Cohen, M.; di Giorgio, A. M.; Liseau, R.; Molinari, S.; Palla, F.; Saraceno, P.; Smith, H. A.; Spinoglio, L.; White, G. J.

1999-06-01

42

ISO-LWS Observations Of Gas And Dust In The Galactic Centre  

NASA Astrophysics Data System (ADS)

The ISO-LWS observed Sagittarius A* over the wavelength range of 46-197 ?m. These previously unpublished spectra contain about 22 spectral lines in emission of atomic and ionic species (OI, OIII, CII, NII and NIII), as well as emission and absorption lines from molecular species (OH, CH, CO and o-H2O). ISO mapped the region in a 40 position, half-beam sampled grid, and used both the grating and Fabry-Perot modules. We have prepared spectral maps of most of the lines, but here discuss primarily the radiative transfer modelling of radiation within the central beam on Sgr A*. We used ISO-LWS spectra to constrain the physical conditions in Sgr A* by comparing the observed spectra with the emission and the absorption line intensities predicted via radiative transfer simulations. Preliminary results show that the spectral energy distribution of Sgr A* within the 80" ISO beam that includes the CND is due to thermal dust emission that can be fitted by the sum of an 85 K modified blackbody arising from a central cavity of r=1.2 pc in radius with a low column density of N(H2)=4.0x1021 cm2, and a 40.5 K modified blackbody curve and a higher column density, N(H2)= 3.0x1022 cm2. This simple model is able to reproduce most of the ionic lines, which are excited in the CND; the central cavity provides only a small contribution to the intensity of the spectral lines. The molecular lines, and in particular the OH absorption features, require substantive additional contributions from foreground absorption that is consistent with a visual extinction AV 30, the same value that is derived from other studies.

Etxaluze Azkonaga, Mireya; Smith, H.; Gonzalez-Alfonso, E.; White, G. J.

2011-01-01

43

Gas and dust in the Galactic Centre - ISO LWS, submillimetre line and continuum observations.  

NASA Astrophysics Data System (ADS)

The Infrared Space Observatory (ISO) Long wavelength Spectrometer (LWS) has been used to map distribution of the emission from a sample of 22 atomic, molecular and ionised lines toward the Circumnuclear Disk at the Galactic Centre. The circumnuclear disc is clearly seen in the maps of molecular lines such as CO and OH, whilst the central region dominates in other atomic and ionised lines such as [O III] and [N III]. The ISO-LWS spectrum toward Sgr A^* is best represented by the sum of three blackbody curves of 90, 44.5 and 16 K, superposed with 22 lines, including CO, OH, [O I], [O III], [N II], [C II] and H_2O. The CO 4.7 ?m absorption band head observed with the ISO SWS spectrometer toward SgrA^* is modeled as having a cold component with Trot = 10 K, for which we estimate N(CO)=7.7× 1018 cm-2, N(13CO) = 1.7× 1017 cm-2 and N(C18O)= 2.1× 1016 cm-2, and a warm component by n(H_2) = 1× 10^5 cm-3, T_k = 70 K, N(CO) = 3.9× 1018 cm-2, N(13CO)= N(CO)/40, N(C18O)= N(CO). Observations of hydrogen recombination lines toward SgrA^* are moddeled as representing a line of sight extiction A_V˜ 24 -28 magnitudes. The SCUBA data at 450 and 850 ?m are used in this paper in order to make an estimation of the CND mass of ˜ 2.3× 10^4 M?, after removal of the free-free contribution and the local background.

Etxaluze, M.; White, G. J.; Smith, H. A.; Gonzalez-Alfonso, E.; Stark, A. A.; Stacey, G. J.; Leeks, S. J.; Gatley, I.; Fisher, J.; Pierce-Price, D.; Richer, J. S.; Grundy, T. W.; Polehampton, E. T.

2011-05-01

44

Teleost multiple tissue ( tmt) opsin: a candidate photopigment regulating the peripheral clocks of zebrafish?  

Microsoft Academic Search

Isolated organs and cell lines from zebrafish exhibit circadian oscillations in clock gene expression that can be entrained to a 24-h light\\/dark cycle. The mechanism underlying this cellular photosensitivity is unknown. We report the identification of a novel opsin family, tmt-opsin, that has a genomic structure characteristic of vertebrate photopigments, an amino acid identity equivalent to the known photopigment opsins,

Paraskevi Moutsaki; David Whitmore; James Bellingham; Katsuhiko Sakamoto; Zoë K. David-Gray; Russell G. Foster

2003-01-01

45

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.

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

2008-01-01

46

Short wavelength-sensitive opsins from the Saharan silver and carpenter ants.  

PubMed

We have previously cloned the opsins coding for the long-wavelength visual pigments from the Saharan silver ant and carpenter ant. Here we report two new cDNA clones isolated from cDNA libraries which also code for opsin proteins. These cDNAs code for deduced proteins with 369 amino acids which are 91% identical to each other, but only 38% identical to the previously cloned opsins. Phyletic comparisons suggest that these opsins are likely the ultraviolet sensitive visual pigments, a conclusion that is supported by the presence of a phenylalanine at the counterion position in the third transmembrane segment. PMID:9706701

Smith, W C; Ayers, D M; Popp, M P; Hargrave, P A

1997-06-01

47

A Non-Mammalian Type Opsin 5 Functions Dually in the Photoreceptive and Non-Photoreceptive Organs of Birds  

Microsoft Academic Search

A mammalian type opsin 5 (neuropsin) is a recently identified ultraviolet (UV)-sensitive pigment of the retina and other photosensitive organs in birds. Two other opsin 5-related molecules have been found in the genomes of non-mammalian vertebrates. However, their functions have not been examined as yet. Here, we identify the molecular properties of a second avian opsin 5, cOpn5L2 (chicken opsin

Hideyo Ohuchi; Takahiro Yamashita; Sayuri Tomonari; Sari Fujita-Yanagibayashi; Kazumi Sakai; Sumihare Noji; Yoshinori Shichida

2012-01-01

48

ISO SWS-LWS observations of the prototypical reflection nebula NGC 7023  

NASA Astrophysics Data System (ADS)

We present SWS and LWS ISO observations towards a strip across the photodissociation region (PDR) in the reflection nebula NGC 7023. SWS02 and LWS01 spectra have been taken towards the star and the brightest infrared filaments located NW and SW from the star (hereafter NW and SW PDRs). In addition, SWS02 spectra have been taken towards two intermediate positions (NW1 and SW1). This has provided important information about the extent and spatial distribution of the warm H_2 and of the atomic species in this prototypical reflection nebula. Strong emission of the [SiII] 34.8$ mum line is detected towards the star. While all the PDR tracers (the [CII] 157.7 mum , [OI] 63.2 and 145.6 mum , [HI] 21cm and the H_2 rotational lines) present a ring-like morphology with the peaks toward the NW and SW PDRs and a mini?m around the star, the SiII emission is filling the hole of this ring with the peak towards the star. This morphology can only be explained if the SiII emission arise in the lowest extinction layers of the PDR (A_v < 2 mag) and the HII region. At least 20% - 30% of the Si must be in gas phase in these layers. For A_v >= 2 mag, the Si is mainly in solid form (\\delta Si = -1.3). The NW and SW PDRs have very similar excitation conditions, high density filaments (n~ 10^6 cm^{-3}) immersed in a more diffuse interfilament medium (n~ 10^4 cm^{-3}). In both, the NW and SW PDRs, the intensities of the H_2 rotational lines can only be fitted by assuming an ortho-to-para-H_2 ratio lower than 3 in gas with rotation temperatures from 400 to 700 K. Therefore, there is a non-equilibrium OTP ratio in the region. Furthermore, the comparison between the OTP ratio derived from H_2 vibrational lines and the pure H_2 rotational lines, shows that the OTP ratio increases from ~ 1.5 to 3 across the photodissociation region with larger values in the less shielded gas (A_v$< 0.7 mag). This behavior is interpreted as a consequence of an advancing photodissociation front. We have not detected the OH, CH and CH_2 lines towards the observed positions. This is consistent with the weakness of these lines in other sources and can be explained as a consequence of the small beam filling factor of the dense gas in the LWS aperture. The CO J=17->16 line has been tentatively detected towards the star. Based on observations with ISO, an ESA project with instruments funded by ESA Member States (especially the PI countries France, Germany, the Netherlands and the United Kingdom) and with participation of ISAS and NASA

Fuente, A.; Martin-Pintado, J.; Rodriguez-Fernández, N. J.; Cernicharo, J.; Gerin, M.

2000-02-01

49

ISO SWS-LWS observations of the prototypical reflection nebula NGC 7023  

NASA Astrophysics Data System (ADS)

We present SWS and LWS ISO observations towards a strip across the photodissociation region (PDR) in the reflection nebula NGC 7023. SWS02 and LWS01 spectra have been taken towards the star and the brightest infrared filaments located NW and SW from the star (hereafter NW and SW PDRs). In addition, SWS02 spectra have been taken towards two intermediate positions (NW1 and SW1). This has provided important information about the extent and spatial distribution of the warm H2 and of the atomic species in this prototypical reflection nebula. Strong emission of the [SiII] 34.8 ?m line is detected towards the star. While all the PDR tracers (the [CII] 157.7 ?m, [OI] 63.2 and 145.6 ?m, [HI] 21 cm and the H2 rotational lines) present a ring-like morphology with the peaks toward the NW and SW PDRs and a minimum around the star, the SiII emission is filling the hole of this ring with the peak towards the star. This morphology can only be explained if the SiII emission arises in the lowest extinction layers of the PDR (Av < 2 mag) and the HII region. At least 20% - 30% of the Si must be in gas phase in these layers. For Av >= 2 mag, the Si is mainly in solid form (? Si = -1.3). The NW and SW PDRs have very similar excitation conditions, high density filaments (n~ 106 cm-3) immersed in a more diffuse interfilament medium (n~ 104 cm-3). In both, the NW and SW PDRs, the intensities of the H2 rotational lines can only be fitted by assuming an ortho-to-para-H2 ratio lower than 3 in gas with rotation temperatures from 400 to 700 K. Therefore, there is a non-equilibrium OTP ratio in the region. Furthermore, the comparison between the OTP ratio derived from H2 vibrational lines and the pure H2 rotational lines, shows that the OTP ratio increases from ~ 1.5 to 3 across the photodissociation region with larger values in the less shielded gas (Av< 0.7 mag). This behavior is interpreted as a consequence of an advancing photodissociation front.

Fuente, A.; Martin-Pintado, J.; Rodriguez-Fernandez, N. J.; Cernicharo, J.; Gerin, M.

2000-11-01

50

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

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

1993-01-01

51

M-opsin protein degradation is inhibited by MG-132 in Rpe65?/? retinal explant culture  

PubMed Central

Purpose The 65 kDa retinal pigment epithelium-specific protein, RPE65, is an essential enzyme for 11-cis-retinal synthesis in the eye. Mutations of the RPE65 gene in humans result in severe vision loss, and Rpe65?/? mice show early cone photoreceptor degeneration. We used an explant culture system to evaluate whether posttranslational downregulation of M-opsin protein in Rpe65?/? mice is caused by proteolytic degradation. Methods The eyes of three-week-old Rpe65?/? mice were incubated in culture medium. Western blot analysis was used to evaluate the level of M-opsin protein, and immunofluorescence was used for protein localization. The transcriptional level of M-opsin was evaluated with real-time reverse-transcriptase-PCR. Results Degradation of the M-opsin protein in Rpe65?/? mouse retina was inhibited by the proteasome inhibitor MG-132 but not by the lysosomal inhibitor pepstatin A and E64d. 9-cis-retinal, used as an analog of 11-cis-retinal, increased M-opsin protein but did not increase M-opsin mRNA. Moreover, 9-cis-retinal did not change the transcriptional levels of photoreceptor specific genes. Conclusions Our data suggest that M-opsin protein was degraded through a proteasome pathway and that M-opsin degradation was suppressed with 9-cis-retinal treatment in Rpe65?/? mice to some extent.

Sato, Kota; Ozaki, Taku; Ishiguro, Sei-ichi

2012-01-01

52

Differential Expression of Duplicated Opsin Genes in Two EyeTypes of Ostracod Crustaceans  

Microsoft Academic Search

In the first molecular study of ostracod (Crustacea) vision, we present partial cDNA sequences of ostracod visual pigment genes (opsins). We found strong support for differential expression of opsins in ostracod median and compound eyes and suggest that photoreceptor specific expression may be a general phenomenon in organisms with multiple receptors. We infer that eye-specific expression predates the divergence of

Todd H. Oakley; Daniel R. Huber

2004-01-01

53

A Laser Welding and Scribing (LWS) Method for a High-Yield Integrated-Type aSi Solar Cell  

Microsoft Academic Search

A new fabrication method for integrated-type amorphous-silicon (a-Si) solar cell submodules, called the laser welding and scribing (LWS) method, was investigated. The conditions for laser scribing and laser welding were calculated from a three-dimensional thermal analysis of a multilayer structure. Calculated results were confirmed by experiment, and the optimum laser power density range for scribing was found to be much

Yasuo Kishi; Kenji Murata; Hiroshi Inoue; Seiichi Kiyama; Michitoshi Ohnishi; Shoichi Nakano; Yukinori Kuwano

1991-01-01

54

ISO LWS Observations of the Two Nearby Spiral Galaxies NGC 6946 and NGC 1313  

NASA Astrophysics Data System (ADS)

We present the analysis of Infrared Space Observatory long-wavelength spectrometer (LWS) observations of the two nearby late-type galaxies NGC 1313 and NGC 6946. Both galaxies have been fully mapped in the [C II] far-infrared fine-structure line at 158 ?m, and some regions have been observed also in the [O I] 63 ?m and [N II] 122 ?m lines. We use these observations to derive the physical properties of the atomic interstellar medium, to establish how they relate to other interstellar medium components (gas and dust), and to establish how they vary with different galaxy components such as nucleus, spiral arms, and disk. The [C II] line is the main cooling line of the atomic medium. In NGC 6946 and NGC 1313, its emission represents 0.8% of the infrared emission. Moreover, the [C II] emission can be spatially associated with three components: the nucleus, the star-forming regions in spiral arms, and the diffuse galaxy disk. This last component contributes <~40% in NGC 6946 and ~30% in NGC 1313 to the total emission. We apply the photodissociation region (PDR) model by Kaufman et al. to derive PDR physical parameters responsible for the neutral atomic gas emission (G0, n, and Ts). The results do not significantly differ from what Malhotra et al. recently found by modeling the integrated emission of a sample of 60 normal galaxies. This suggests that the emission in each region under the LWS beam in NGC 6946 and NGC 1313 (corresponding to a linear size of ~1.5 kpc) is likely to arise from a mixture of components similar to the mixture producing the integrated emission of normal galaxies. However, some regions in NGC 6946 have a G0/n ratio ~2-3 times smaller than the mean value found for the normal galaxy sample (1.3), suggesting that the beam-averaged contribution of a less active component in these regions is higher than its contribution in the integrated emission of normal galaxies or, conversely, that the bulk of the integrated emission of the normal galaxies is dominated by a few active regions probably located in their nuclei. CO(1-0) and [C II] in NGC 6946 are well correlated, and the mean [C II]/CO ratio agrees with the mean integrated ratios of the normal galaxies sample. This value (~500) is a factor of ~2 less than the mean ratio found for a sample of normal galaxies observed with the Kupier Airborne Observatory (KAO) by Stacey et al. This difference is probably due to the fact that the KAO beam (55") is smaller than the LWS beam (75"), such that the Stacey et al. KAO observations are likely to be more biased toward the nucleus of the galaxies and therefore toward more active regions. In NGC 1313 only four LWS regions have been observed in CO(1-0), and three of them were detected. The [C II]/CO(1-0) seems to systematically increase from the northeast to the south, along the S-shaped spiral arm, indicating that the interstellar medium conditions in NGC 1313 are much more inhomogeneous than the conditions in NGC 6946. H I and [C II] in NGC 6946 are completely uncorrelated, probably because they arise from different gas components: [C II] arises principally in dense and warm PDR and H I from diffuse (n<~3×103 cm-3) gas. On the other hand, in NGC 1313 we successfully detect two distinct gas components: a cirrus-like component, for which H I and [C II] are weakly correlated as observed in our Galaxy, and a component associated with dense PDRs completely uncorrelated from H I as observed in NGC 6946. Finally, we find that the H I residing in dense gas surrounding the star-forming regions and presumably recently photodissociated constitutes a few percent of the total H I. In turn, this dense gas component produces most of the [C II] emission emitted by the atomic neutral medium, even if its contribution is lower in NGC 1313 than in NGC 6946. On the other hand, the [C II] emission arising from ionized gas is higher in NGC 1313 than in NGC 6946.

Contursi, Alessandra; Kaufman, Michael J.; Helou, George; Hollenbach, David J.; Brauher, James; Stacey, Gordon J.; Dale, Daniel A.; Malhotra, Sangeeta; Rubio, Monica; Rubin, Robert H.; Lord, Steven D.

2002-08-01

55

The Need for NASA's LWS Ionosphere-Thermosphere Storm Probe Mission  

NASA Astrophysics Data System (ADS)

NASA's LWS Geospace Programs has defined a sequence of space missions dedicated to making the most advances in science understanding dealing with the immediate impacts of geospace on humans and their technology systems. One of these focused missions, the Radiation Belt Storm Probes is being implemented with the recent NASA Announcement of Opportunity for instrument proposals. The launch date of the other Geospace mission, the Ionosphere-Thermosphere Storm Probes (I-TSP), has consequently been delayed until the middle of the next decade. This changes its planned coordination with other space resources like the EVE instrument on SDO, but does not affect the importance of the two in situ measuring spacecraft compromising the I-T Storm Probes. Indeed, since the original science definition of the mission increasing concern has been expressed by the US Department of Defense and private industry about communication, guidance disturbances and spacecraft orbit perturbations resulting from the ionosphere-thermosphere properties that the I-TSP's will be configured to understand. The practical value of this mission and the focusing of its instruments, orbit configuration and collaborative observations on understanding the underlying physics of how the I-T system impacts human systems will be shown.

Grebowsky, J. M.; Sibeck, D. G.

2006-05-01

56

The halo-opsin gene. I. Identification and isolation.  

PubMed

Halorhodopsin (HR), the light-driven chloride pump in halobacteria, was purified in the denatured as well as in the native state and chemically cleaved into peptide fragments. Isolation of peptide and liquid phase sequencing yielded approximately 20% of the halo-opsin (HO) structure in non-overlapping peptides. Chemically synthesized oligodeoxynucleotides corresponding to a peptide sequence obtained from both HR preparations were used to screen a cosmid gene bank of Halobacterium halobium strain L-33. A positive clone contained cosmid pAB H47 which by subcloning and nucleotide sequencing was shown to encode at least part of the HO gene. PMID:15981335

Hegemann, P; Blanck, A; Vogelsang-Wenke, H; Lottspeich, F; Oesterhelt, D

1987-01-01

57

Genomic and gene regulatory signatures of cryptozoic adaptation: Loss of blue sensitive photoreceptors through expansion of long wavelength-opsin expression in the red flour beetle Tribolium castaneum  

Microsoft Academic Search

BACKGROUND: Recent genome sequence analysis in the red flour beetle Tribolium castaneum indicated that this highly crepuscular animal encodes only two single opsin paralogs: a UV-opsin and a long wavelength (LW)-opsin; however, these animals do not encode a blue (B)-opsin as most other insects. Here, we studied the spatial regulation of the Tribolium single LW- and UV-opsin gene paralogs in

Magdalena Jackowska; Riyue Bao; Zhenyi Liu; Elizabeth C McDonald; Tiffany A Cook; Markus Friedrich

2007-01-01

58

Opsin evolution in damselfish: convergence, reversal, and parallel evolution across tuning sites.  

PubMed

The visual system plays a role in nearly every aspect of an organism's life history, and there is a direct link between visual pigment phenotypes and opsin genotypes. In previous studies of African cichlid fishes, we found evidence for positive selection among some opsins, with sequence variation greatest for opsins producing the shortest and longest wavelength visual pigments. In this study, we examined opsin evolution in the closely related damselfish family (Pomacentridae), a group of reef fishes that are distributed widely and have a documented fossil record of at least 50 million years (MY). We found increased functional variation in the protein sequences of opsins at the short- and long-wavelength ends of the visual spectrum, in agreement with the African cichlids, despite an order of magnitude difference in the ages of the two radiations. We also reconstructed amino acid substitutions across opsin tuning sites. These reconstructions indicated multiple instances of parallel evolution, at least one definitive case of convergent evolution, and one evolutionary reversal. Our findings show that the amino acids at spectral tuning sites are labile evolutionarily, and that the same codons evolve repeatedly. These findings emphasize that the aquatic light environment can shape opsin sequence evolution. They further show that phylogenetic approaches can provide important insights into the mechanisms by which natural selection "tinkers" with phenotypes. PMID:23080353

Hofmann, Christopher M; Marshall, N Justin; Abdilleh, Kawther; Patel, Zil; Siebeck, Ulrike E; Carleton, Karen L

2012-10-19

59

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

60

Gene conversion and purifying selection shape nucleotide variation in gibbon L/M opsin genes  

PubMed Central

Background Routine trichromatic color vision is a characteristic feature of catarrhines (humans, apes and Old World monkeys). This is enabled by L and M opsin genes arrayed on the X chromosome and an autosomal S opsin gene. In non-human catarrhines, genetic variation affecting the color vision phenotype is reported to be absent or rare in both L and M opsin genes, despite the suggestion that gene conversion has homogenized the two genes. However, nucleotide variation of both introns and exons among catarrhines has only been examined in detail for the L opsin gene of humans and chimpanzees. In the present study, we examined the nucleotide variation of gibbon (Catarrhini, Hylobatidae) L and M opsin genes. Specifically, we focused on the 3.6~3.9-kb region that encompasses the centrally located exon 3 through exon 5, which encode the amino acid sites functional for the spectral tuning of the genes. Results Among 152 individuals representing three genera (Hylobates, Nomascus and Symphalangus), all had both L and M opsin genes and no L/M hybrid genes. Among 94 individuals subjected to the detailed DNA sequencing, the nucleotide divergence between L and M opsin genes in the exons was significantly higher than the divergence in introns in each species. The ratio of the inter-LM divergence to the intra-L/M polymorphism was significantly lower in the introns than that in synonymous sites. When we reconstructed the phylogenetic tree using the exon sequences, the L/M gene duplication was placed in the common ancestor of catarrhines, whereas when intron sequences were used, the gene duplications appeared multiple times in different species. Using the GENECONV program, we also detected that tracts of gene conversions between L and M opsin genes occurred mostly within the intron regions. Conclusions These results indicate the historical accumulation of gene conversions between L and M opsin genes in the introns in gibbons. Our study provides further support for the homogenizing role of gene conversion between the L and M opsin genes and for the purifying selection against such homogenization in the central exons to maintain the spectral difference between L and M opsins in non-human catarrhines.

2011-01-01

61

Primary Structure of Locust Opsins: a Speculative Model Which May Account for Ultraviolet Wavelength Light Detection  

Microsoft Academic Search

The sequences of two locust opsins have been determined by dideoxy nucleotide sequencing of PCR products from cDNA derived from eyecup tissue. The opsins (Lo1 and Lo2) are encoded by 381 and 380 amino acid residues, respectively, with hydropathy profiles and placement of key amino acid residues suggestive of a typical seven-transmembrane rhodopsin structure. The sequence alignment of Lo1 reveals

PAUL TOWNER; PHIL HARRIS; ADRIAN J. WOLSTENHOLME; CHRISTIANE HILL; KARL WORM; WOLFGANG GÄRTNER

1997-01-01

62

Uncovering a gene duplication of the photoreceptive protein, opsin, in scallops (bivalvia: pectinidae).  

PubMed

Evolutionary biologists have long been interested in how expansions of the photosensory system might contribute to morphological differentiation of animals. Comparative studies in vertebrate and arthropod lineages have provided considerable insight into how the duplication of opsin, the first gene of the phototransduction pathway, have led to functional differentiation and new ecological opportunities; however, this relationship cannot be examined in many invertebrate groups as we have yet to characterize their opsin content. Scallops (Pectinidae) are a promising molluscan model to study the evolution of opsin and its potential role in speciation. Recently, we discovered a second Gq-coupled, or r-, opsin gene expressed in the eyes of two scallop species. To investigate the evolutionary origin of this opsin, we screened 12 bivalve species from 4 families, representing both mobile and sessile species, with and without eyes. Although only one ortholog was recovered from the genome of the eyeless, immobile oyster, we found both genes to have been retained in 3 families comprising the order Pectinoida. Within this clade, non-mobile species of scallops appear to have lost one gene. Phylogeny-based tests of selection indicate different degrees of purifying selection following duplication. These data, in conjunction with highly divergent gene sequences and ortholog-specific retention, suggest functional differences. Our results are congruent with a Gq-opsin gene duplication in an oyster-Pectinoida ancestor, approximately 470 Mya, and suggest the likelihood of retaining both genes is associated with either the presence of eyes and/or degree of mobility. The identification of two highly divergent Gq-opsin genes in scallops is valuable for future functional investigations and provides a foundation for further study of a morphologically and ecologically diverse clade of bivalves that has been understudied with respect to visual ecology and diversification of opsin. PMID:23748632

Serb, Jeanne M; Porath-Krause, Anita J; Pairett, Autum N

2013-06-07

63

Ant opsins: Sequences from the Saharan silver ant and the carpenter ant  

Microsoft Academic Search

cDNA clones encoding opsins from compound eyes of carpenter ant,Camponotus abdominalis, and Saharan silver ant,Cataglyphis bombycina, were isolated from cDNA libraries. The opsin cDNAs from each species code for deduced proteins with 378 amino acids which are 92% identical. Of the 30 amino acid differences between the two proteins, 13 are non-conservative. Eight of these non-conservative substitutions are within the

Michael P. Popp; Reinhard Grisshammer; Paul A. Hargrave; W. Clay Smith

1996-01-01

64

Short wavelength-sensitive opsins from the Saharan silver and carpenter Ants  

Microsoft Academic Search

We have previously cloned the opsins coding for the long-wavelength visual pigments from the Saharan silver ant and carpenter\\u000a ant. Here we report two new cDNA clones isolated from cDNA libraries which also code for opsin proteins. These cDNAs code\\u000a for deduced proteins with 369 amino acids which are 91% identical to each other, but only 38% identical to the

W. Clay Smith; Donald M. Ayers; Michael P. Popp; Paul A. Hargrave

1997-01-01

65

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

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

1995-01-01

66

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

67

Searching for Ejecta and Dust Formation Signatures in Young Supernova Remnants with ISO/LWS and Herschel  

NASA Astrophysics Data System (ADS)

We report infrared detected supernova remnants (SNRs) from ISO/LWS archival data. The ionic lines and continuum of mid- to far- infrared spectroscopy using ISO/LWS were carefully examined. We have found 10-15 useful detections of infrared emission in supernova remnants. As the first project using ISO data, we identified 4 new young SNRs showing broad ionic lines. Broad ionic lines are signatures of ejecta in which dust may form. G54.1+0.3 shows broad lines of [OIII] at 88 micron, [O I] at 63 micron and [N II] at 122 micron. G320.3-1.2 (MSH15-52) shows broad lines of both [OIII] at 52 and 88 micron and [N II] at 122 micron. G21.5-0.9 and MSH11-54 show a broad line of only [N II] at 122 micron. We detect [C II] lines at 158 micron from all of the four sample SNRs, but they are not resolved within instrument resolution. We also present the archival Herschel imaging data of the four SNRs and will estimate dust masses by combing the ISO spectra and Herschel. For other ISO detected-SNRs, we plan to make ISO catalog of IR-detected SNRs.

Park, Sung-Joon; Rho, J.

2012-01-01

68

EFFECT OF RAPAMYCIN ON THE FATE OF P23H OPSIN ASSOCIATED WITH RETINITS PIGMENTOSA (AN AMERICAN OPHTHALMOLOGICAL SOCIETY THESIS)  

PubMed Central

Purpose To determine the effect of rapamycin on the fate of misfolded opsin associated with retinitis pigmentosa. Methods Stable cell lines separately expressing WT and P23H opsins and WT and ?F508 CFTR were used. Cells were incubated with complete media or amino acid–depleted medium or in the presence of rapamycin. At various time points thereafter, quantitative opsin and CFTR immunoblotting was performed. Immunofluorescence and electron microscopy were also performed to observe the expression and colocalization of autophagy specific marker proteins with opsin or CFTR. Results Upon incubation with rapamycin, the levels of P23H opsin and ?F508 CFTR were reduced more rapidly than in untreated controls while no observable changes in the amounts of WT opsin was seen. The autophagy specific marker proteins, Atg7, Atg8 (LC3), and LAMP-1, which associate with autophagic vacuoles, colocalized with P23H opsin. A dramatic increase in the immunofluorescence signals of Atg7, LC3, and LAMP-1 was observed. All three of these proteins were found to decorate P23H opsin, suggesting that autophagy may be directly responsible for the clearance of this protein. Also, it was determined that neither the unfolded protein response nor the heat shock response was induced upon rapamycin-associated degradation of P23H opsin. Conclusions These data suggest that rapamycin induces the loss of P23H opsin and ?F508 CFTR from the cell under the experimental conditions described. Concomitantly, there is increased expression and colocalization of autophagy marker proteins with P23H opsin. Immunogold electron microscopic studies demonstrate autophagic vacuoles clustered in physical proximity to the aggregates of P23H opsin, suggesting that some of the loss of P23H is related to the induction of autophagy. Thus, rapamycin may be useful to clear misfolded proteins associated with retinal degeneration.

Kaushal, Shalesh

2006-01-01

69

X-Linked Cone Dystrophy Caused by Mutation of the Red and Green Cone Opsins  

PubMed Central

X-linked cone and cone-rod dystrophies (XLCOD and XLCORD) are a heterogeneous group of progressive disorders that solely or primarily affect cone photoreceptors. Mutations in exon ORF15 of the RPGR gene are the most common underlying cause. In a previous study, we excluded RPGR exon ORF15 in some families with XLCOD. Here, we report genetic mapping of XLCOD to Xq26.1-qter. A significant LOD score was detected with marker DXS8045 (Zmax = 2.41 [? = 0.0]). The disease locus encompasses the cone opsin gene array on Xq28. Analysis of the array revealed a missense mutation (c. 529T>C [p. W177R]) in exon 3 of both the long-wavelength-sensitive (LW, red) and medium-wavelength-sensitive (MW, green) cone opsin genes that segregated with disease. Both exon 3 sequences were identical and were derived from the MW gene as a result of gene conversion. The amino acid W177 is highly conserved in visual and nonvisual opsins across species. We show that W177R in MW opsin and the equivalent W161R mutation in rod opsin result in protein misfolding and retention in the endoplasmic reticulum. We also demonstrate that W177R misfolding, unlike the P23H mutation in rod opsin that causes retinitis pigmentosa, is not rescued by treatment with the pharmacological chaperone 9-cis-retinal. Mutations in the LW/MW cone opsin gene array can, therefore, lead to a spectrum of disease, ranging from color blindness to progressive cone dystrophy (XLCOD5).

Gardner, Jessica C.; Webb, Tom R.; Kanuga, Naheed; Robson, Anthony G.; Holder, Graham E.; Stockman, Andrew; Ripamonti, Caterina; Ebenezer, Neil D.; Ogun, Olufunmilola; Devery, Sophie; Wright, Genevieve A.; Maher, Eamonn R.; Cheetham, Michael E.; Moore, Anthony T.; Michaelides, Michel; Hardcastle, Alison J.

2010-01-01

70

X-linked cone dystrophy caused by mutation of the red and green cone opsins.  

PubMed

X-linked cone and cone-rod dystrophies (XLCOD and XLCORD) are a heterogeneous group of progressive disorders that solely or primarily affect cone photoreceptors. Mutations in exon ORF15 of the RPGR gene are the most common underlying cause. In a previous study, we excluded RPGR exon ORF15 in some families with XLCOD. Here, we report genetic mapping of XLCOD to Xq26.1-qter. A significant LOD score was detected with marker DXS8045 (Z(max) = 2.41 [theta = 0.0]). The disease locus encompasses the cone opsin gene array on Xq28. Analysis of the array revealed a missense mutation (c. 529T>C [p. W177R]) in exon 3 of both the long-wavelength-sensitive (LW, red) and medium-wavelength-sensitive (MW, green) cone opsin genes that segregated with disease. Both exon 3 sequences were identical and were derived from the MW gene as a result of gene conversion. The amino acid W177 is highly conserved in visual and nonvisual opsins across species. We show that W177R in MW opsin and the equivalent W161R mutation in rod opsin result in protein misfolding and retention in the endoplasmic reticulum. We also demonstrate that W177R misfolding, unlike the P23H mutation in rod opsin that causes retinitis pigmentosa, is not rescued by treatment with the pharmacological chaperone 9-cis-retinal. Mutations in the LW/MW cone opsin gene array can, therefore, lead to a spectrum of disease, ranging from color blindness to progressive cone dystrophy (XLCOD5). PMID:20579627

Gardner, Jessica C; Webb, Tom R; Kanuga, Naheed; Robson, Anthony G; Holder, Graham E; Stockman, Andrew; Ripamonti, Caterina; Ebenezer, Neil D; Ogun, Olufunmilola; Devery, Sophie; Wright, Genevieve A; Maher, Eamonn R; Cheetham, Michael E; Moore, Anthony T; Michaelides, Michel; Hardcastle, Alison J

2010-06-24

71

Chromatic Properties of Horizontal and Ganglion Cell Responses Follow a Dual Gradient in Cone Opsin Expression  

PubMed Central

In guinea pig retina, immunostaining reveals a dual gradient of opsins: cones expressing opsin sensitive to medium wavelengths (M) predominate in the upper retina, whereas cones expressing opsin sensitive to shorter wavelengths (S) predominate in the lower retina. Whether these gradients correspond to functional gradients in postreceptoral neurons is essentially unknown. Using monochromatic flashes, we measured the relative weights with which M, S, and rod signals contribute to horizontal cell responses. For a background that produced 4.76 log10 photoisomerizations per rod per second (Rh*/rod/s), mean weights in superior retina were 52% (M), 2% (S), and 46% (rod). Mean weights in inferior retina were 9% (M), 50% (S), and 41% (rod). In superior retina, cone opsin weights agreed quantitatively with relative pigment density estimates from immunostaining. In inferior retina, cone opsin weights agreed qualitatively with relative pigment density estimates, but quantitative comparison was impossible because individual cones coexpress both opsins to varying and unquantifiable degrees. We further characterized the functional gradients in horizontal and brisk-transient ganglion cells using flickering stimuli produced by various mixtures of blue and green primary lights. Cone weights for both cell types resembled those obtained for horizontal cells using monochromatic flashes. Because the brisk-transient ganglion cell is thought to mediate behavioral detection of luminance contrast, our results are consistent with the hypothesis that the dual gradient of cone opsins assists achromatic contrast detection against different spectral backgrounds. In our preparation, rod responses did not completely saturate, even at background light levels typical of outdoor sunlight (5.14 log10 Rh*/rod/s).

Yin, Lu; Smith, Robert G; Sterling, Peter; Brainard, David H.

2007-01-01

72

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

PubMed

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

2013-05-22

73

Specific transmembrane segments are selectively delayed at the ER translocon during opsin biogenesis.  

PubMed

A site-specific cross-linking approach was used to study the integration of TM (transmembrane) segments 4-7 of the polytopic membrane protein, opsin, at the ER (endoplasmic reticulum). We found that although TM4 exits the ER translocon rapidly, TM segments 5, 6 and 7 are all retained at the translocon until opsin biosynthesis is terminated. Furthermore, although artificial extension of the nascent chain is not sufficient to release the C-terminal region of opsin from the translocon, substitution of the native TM segment 7 with a more hydrophobic TM segment results in its rapid lateral exit into the lipid bilayer. We conclude that the intrinsic properties of a TM segment determine the timing of its membrane integration rather than its relative location within the polypeptide chain. A pronounced and prolonged association of opsin TM5 with the translocon-associated component PAT-10 was also observed, suggesting that PAT-10 may facilitate the assembly of distinct opsin subdomains during membrane integration. The results of the present study strongly support a model in which the ER translocon co-ordinates the integration of selected TM segments in response to the specific requirements of the precursor being synthesized. PMID:18248332

Ismail, Nurzian; Crawshaw, Samuel G; Cross, Benedict C S; Haagsma, Anna C; High, Stephen

2008-05-01

74

Long-wavelength sensitive visual pigments of the guppy (Poecilia reticulata): six opsins expressed in a single individual  

Microsoft Academic Search

BACKGROUND: The diversity of visual systems in fish has long been of interest for evolutionary biologists and neurophysiologists, and has recently begun to attract the attention of molecular evolutionary geneticists. Several recent studies on the copy number and genomic organization of visual pigment proteins, the opsins, have revealed an increased opsin diversity in fish relative to most vertebrates, brought about

Cameron J Weadick; Belinda SW Chang

2007-01-01

75

Color-deficient cone mosaics associated with Xq28 opsin mutations: A stop codon versus gene deletions  

PubMed Central

Our understanding of the etiology of red-green color vision defects is evolving. While missense mutations within the long- (L-) and middle-wavelength sensitive (M-) photopigments and gross rearrangements within the L/M-opsin gene array are commonly associated with red-green defects, recent work using adaptive optics retinal imaging has shown that different genotypes can have distinct consequences for the cone mosaic. Here we examined the cone mosaic in red-green color deficient individuals with multiple X-chromosome opsin genes that encode L opsin, as well as individuals with a single X-chromosome opsin gene that encodes L opsin and a single patient with a novel premature termination codon in his M-opsin gene and a normal L-opsin gene. We observed no difference in cone density between normal trichomats and multiple or single gene dichromats. In addition, we demonstrate different phenotypic effects of a nonsense mutation versus the previously described deleterious polymorphism, (LIAVA), both of which differ from multiple and single gene dichromats. Our results help refine the relationship between opsin genotype and cone photoreceptor mosaic phenotype.

Wagner-Schuman, Melissa; Neitz, Jay; Rha, Jungtae; Williams, David R.; Neitz, Maureen; Carroll, Joseph

2010-01-01

76

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

77

Interconversion of red opsin isoforms by the cyclophilin-related chaperone protein Ran-binding protein 2  

PubMed Central

Ran-binding protein 2 (RanBP2) (type II) is a retinal cyclophilin-related protein that binds Ran-GTPase. Type I cyclophilin is a shorter, alternatively spliced isoform of RanBP2. Recently, we showed that the Ran-binding domain 4 (RBD4)/cyclophilin (CY) supradomain of RanBP2 acts both in vitro and in vivo as a specific chaperone for bovine red/green opsin (R/G opsin). R/G opsin undergoes a stable modification of its electrophoretic mobility upon binding to RanBP2. This modification is likely due to cis–trans isomerization of one or more proline residues in the opsin protein. Here, we show that expression of human red opsin in Escherichia coli and COS cells results in the production of still a third electrophoretic variant of this protein. This variant was converted to the RBD4 binding-competent form of opsin through direct interaction with RBD4/CY, both in vivo and in vitro. We suggest that these distinct opsin species may represent kinetically or thermodynamically trapped prolyl conformers that can be interconverted by concerted action of the RBD4 and CY domains of RanBP2. We also show that the C-terminal half of RBD4 is the binding domain for bovine R/G opsin and that coexpression of human red opsin with type I cyclophilin in vivo enhances the production of functional visual pigment. These observations imply that prolyl isomerization may have importance beyond its role in protein folding, possibly as a molecular switch modulated by cyclophilin for the loading of opsin onto RanBP2 during visual pigment processing in cones.

Ferreira, Paulo A.; Nakayama, Tomoko A.; Travis, Gabriel H.

1997-01-01

78

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

79

Opsins and clusters of sensory G-protein-coupled receptors in the sea urchin genome.  

PubMed

Rhodopsin-type G-protein-coupled receptors (GPCRs) contribute the majority of sensory receptors in vertebrates. With 979 members, they form the largest GPCR family in the sequenced sea urchin genome, constituting more than 3% of all predicted genes. The sea urchin genome encodes at least six Opsin proteins. Of these, one rhabdomeric, one ciliary and two G(o)-type Opsins can be assigned to ancient bilaterian Opsin subfamilies. Moreover, we identified four greatly expanded subfamilies of rhodopsin-type GPCRs that we call sea urchin specific rapidly expanded lineages of GPCRs (surreal-GPCRs). Our analysis of two of these groups revealed genomic clustering and single-exon gene structures similar to the most expanded group of vertebrate rhodopsin-type GPCRs, the olfactory receptors. We hypothesize that these genes arose by rapid duplication in the echinoid lineage and act as chemosensory receptors of the animal. In support of this, group B surreal-GPCRs are most prominently expressed in distinct classes of pedicellariae and tube feet of the adult sea urchin, structures that have previously been shown to react to chemical stimuli and to harbor sensory neurons in echinoderms. Notably, these structures also express different opsins, indicating that sea urchins possess an intricate molecular set-up to sense their environment. PMID:17067569

Raible, Florian; Tessmar-Raible, Kristin; Arboleda, Enrique; Kaller, Tobias; Bork, Peer; Arendt, Detlev; Arnone, Maria I

2006-09-05

80

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

PubMed Central

Background Animals often display phenotypic plasticity in morphologies and behaviors that result in distinct adaptations to fluctuating seasonal environments. The butterfly Bicyclus anynana has two seasonal forms, wet and dry, that vary in wing ornament brightness and in the identity of the sex that performs the most courting and choosing. Rearing temperature is the cue for producing these alternative seasonal forms. We hypothesized that, barring any developmental constraints, vision should be enhanced in the choosy individuals but diminished in the non-choosy individuals due to physiological costs. As a proxy of visual performance we measured eye size, facet lens size, and sensitivity to light, e.g., the expression levels of all opsins, in males and females of both seasonal forms. Results We found that B. anynana eyes displayed significant sexual dimorphism and phenotypic plasticity for both morphology and opsin expression levels, but not all results conformed to our prediction. Males had larger eyes than females across rearing temperatures, and increases in temperature produced larger eyes in both sexes, mostly via increases in facet number. Ommatidia were larger in the choosy dry season (DS) males and transcript levels for all three opsins were significantly lower in the less choosy DS females. Conclusions Opsin level plasticity in females, and ommatidia size plasticity in males supported our visual plasticity hypothesis but males appear to maintain high visual function across both seasons. We discuss our results in the context of distinct sexual and natural selection pressures that may be facing each sex in the wild in each season.

2012-01-01

81

Two opsins from the compound eye of the crab Hemigrapsus sanguineus  

PubMed

The primary structures of two opsins from the brachyuran crab Hemigrapsus sanguineus were deduced from the cDNA nucleotide sequences. Both deduced proteins were composed of 377 amino acid residues and included residues highly conserved in visual pigments of other species, and the proteins were 75 % identical to each other. The distribution of opsin transcripts in the compound eye, determined by in situ hybridization, suggested that the mRNAs of the two opsins were expressed simultaneously in all of the seven retinular cells (R1-R7) forming the main rhabdom in each ommatidium. Two different visual pigments may be present in one photoreceptor cell in this brachyuran crab. The spectral sensitivity of the compound eye was also determined by recording the electroretinogram. The compound eye was maximally sensitive at about 480 nm. These and previous findings suggest that both opsins of this brachyuran crab produce visual pigments with maximal absorption in the blue-green region of the spectrum. Evidence is presented that crustaceans possess multiple pigment systems for vision. PMID:9318091

Sakamoto; Hisatomi; Tokunaga; Eguchi

1996-01-01

82

Development of a New Trapped Radiation Data Base for the NASA Living With A Star (LWS) Program  

NASA Astrophysics Data System (ADS)

As an initial effort to construct a new-generation of empirical trapped radiation models, a new magnetospheric state-based trapped radiation database is being constructed. An empirical model of a system is a statistical description of the system obtained by synthesizing a set of random samplings of the system. The key to constructing good empirical models thus depends on (1) having good (pertinent) data, and (2) good analysis techniques. To mitigate against early obselescence when updated or new data becomes available, the models' underlying database must be update-able and extensible. In addition, to ensure high model performance, the data base must be parameterize-able, so that the selection of data from the data base for analysis or modeling can vary with magnetospheric conditions or states that vary with solar wind and IMF driving conditions and magnetospheric responses [see Fung, 1996]. By following an object-oriented design, the new trapped radiation data base can be easily updated, extended and re-parameterized. In this paper, we describe our effort in constructing a prototype particle radiation data base for the LWS Program. Fung, S. F., Recent development in the NASA trapped radiation models, Radiation Belts Models and Standards, Geophysical Monogr., 97, AGU, Washington, D. C., 79-91, 1996.

Fung, S. F.; Bell, E. V.; Candey, R. M.; Golightly, M. J.; Huston, S. L.; King, J. H.; McGuire, R. E.; Tan, L. C.

2002-05-01

83

Convergent loss of an anciently duplicated, functionally divergent RH2 opsin gene in the fugu and Tetraodon pufferfish lineages  

Microsoft Academic Search

We describe the complete opsin gene families from the sequenced fugu and Tetraodon pufferfish genomes. We report the convergent loss of function of an anciently duplicated, functionally divergent RH2 or “green-sensitive” opsin gene in both pufferfish lineages, designated RH2-2. In fugu, RH2-2 apparently ceased to function very recently following a transposon-induced deletion that truncated the N-terminal 115 amino acids from

Daniel E. NeafseyT; Daniel L. Hartl

2005-01-01

84

Coupling and decoupling of evolutionary mode between X- and Y-chromosomal red-green opsin genes in owl monkeys  

Microsoft Academic Search

We previously discovered Y-chromosomal red-green opsin genes in two types of owl monkeys with different chromosomal characteristics. In one type, the Y-linked opsin gene is a single-copy intact gene and in the other, the genes exist as multiple pseudogenes on a Y\\/autosome fusion chromosome. In the present study, we first distinguished the two types of monkeys as distinct allopatric species

Kenji Nagao; Naomi Takenaka; Momoki Hirai; Shoji Kawamura

2005-01-01

85

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

86

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

PubMed

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

Iwagawa, Toshiro; Tanaka, Yo; Iida, Atsumi; Itoh, Toshio; Watanabe, Sumiko

2013-08-23

87

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.

Iida, Atsumi; Itoh, Toshio; Watanabe, Sumiko

2013-01-01

88

Analysis of the Promoter of the ninaE Opsin Gene in Drosophila melanogaster  

Microsoft Academic Search

We have analyzed the cis-acting regulatory sequences of the ninaE gene. This gene encodes the major Drosophila melanogaster opsin, the protein component of the primary chromophore of photo- receptor cells RlLR6 of the adult eye. DNA fragments containing the start point of transcription of the ninaE gene were fused to either the Escherichia coli chloramphenicol acetyltransferase or lac2 (P- galactosidase)

Drzislav Mismer; Gerald M. Rubin

1987-01-01

89

Calorimetric Studies of Bovine Rod Outer Segment Disk Membranes Support a Monomeric Unit for Both Rhodopsin and Opsin  

PubMed Central

The photoreceptor rhodopsin is a G-protein coupled receptor that has recently been proposed to exist as a dimer or higher order oligomer, in contrast to the previously described monomer, in retinal rod outer segment disk membranes. Rhodopsin exhibits considerably greater thermal stability than opsin (the bleached form of the receptor), which is reflected in an ?15°C difference in the thermal denaturation temperatures (Tm) of rhodopsin and opsin as measured by differential scanning calorimetry. Here we use differential scanning calorimetry to investigate the effect of partial bleaching of disk membranes on the Tm of rhodopsin and of opsin in native disk membranes, as well as in cross-linked disk membranes in which rhodopsin dimers are known to be present. The Tms of rhodopsin and opsin are expected to be perturbed if mixed oligomers are present. The Tm remained constant for rhodopsin and opsin in native disks regardless of the level of bleaching. In contrast, the Tm of cross-linked rhodopsin in disk membranes was dependent on the extent of bleaching. The energy of activation for denaturation of rhodopsin and cross-linked rhodopsin was calculated. Cross-linking rhodopsin significantly decreased the energy of activation. We conclude that in native disk membranes, rhodopsin behaves predominantly as a monomer.

Edrington, Thomas C.; Bennett, Michael; Albert, Arlene D.

2008-01-01

90

Electrostatic Compensation Restores Trafficking of the Autosomal Recessive Retinitis Pigmentosa E150K Opsin Mutant to the Plasma Membrane*  

PubMed Central

Rhodopsin is the rod photoreceptor G protein-coupled receptor responsible for capturing light. Mutations in the gene encoding this protein can lead to a blinding disease called retinitis pigmentosa, which is inherited frequently in an autosomal dominant manner. The E150K opsin mutant associated with rarely occurring autosomal recessive retinitis pigmentosa localizes to trans-Golgi network membranes rather than to plasma membranes of rod photoreceptor cells. We investigated the molecular mechanisms underlying opsin retention in the Golgi apparatus. Electrostatic calculations reveal that the E150K mutant features an overall accumulation of positive charges between helices H-IV and H-II. Human E150K and several other closely related opsin mutants were then expressed in HEK-293 cells. Spectral characteristics and functional biochemistry of each mutant were analyzed after reconstitution with the cis-retinoid chromophore. UV-visible spectra and rhodopsin/transducin activation assays revealed only minor differences between the purified wild type control and rhodopsin mutants. However, partial restoration of the surface electrostatic charge in the compensatory R69E/E150K double mutant rescues the plasma membrane localization of opsin. These findings emphasize the fundamental importance of electrostatic interactions for appropriate membrane trafficking of opsin and advance our understanding of the pathophysiology of autosomal recessive retinitis pigmentosa due to the E150K mutation.

Pulagam, Lakshmi Padmavathi; Palczewski, Krzysztof

2010-01-01

91

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.

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

2011-01-01

92

Co-expression of VAL- and TMT-opsins uncovers ancient photosensory interneurons and motorneurons in the vertebrate brain.  

PubMed

The functional principle of the vertebrate brain is often paralleled to a computer: information collected by dedicated devices is processed and integrated by interneuron circuits and leads to output. However, inter- and motorneurons present in today's vertebrate brains are thought to derive from neurons that combined sensory, integration, and motor function. Consistently, sensory inter-motorneurons have been found in the simple nerve nets of cnidarians, animals at the base of the evolutionary lineage. We show that light-sensory motorneurons and light-sensory interneurons are also present in the brains of vertebrates, challenging the paradigm that information processing and output circuitry in the central brain is shielded from direct environmental influences. We investigated two groups of nonvisual photopigments, VAL- and TMT-Opsins, in zebrafish and medaka fish; two teleost species from distinct habitats separated by over 300 million years of evolution. TMT-Opsin subclasses are specifically expressed not only in hypothalamic and thalamic deep brain photoreceptors, but also in interneurons and motorneurons with no known photoreceptive function, such as the typeXIV interneurons of the fish optic tectum. We further show that TMT-Opsins and Encephalopsin render neuronal cells light-sensitive. TMT-Opsins preferentially respond to blue light relative to rhodopsin, with subclass-specific response kinetics. We discovered that tmt-opsins co-express with val-opsins, known green light receptors, in distinct inter- and motorneurons. Finally, we show by electrophysiological recordings on isolated adult tectal slices that interneurons in the position of typeXIV neurons respond to light. Our work supports "sensory-inter-motorneurons" as ancient units for brain evolution. It also reveals that vertebrate inter- and motorneurons are endowed with an evolutionarily ancient, complex light-sensory ability that could be used to detect changes in ambient light spectra, possibly providing the endogenous equivalent to an optogenetic machinery. PMID:23776409

Fischer, Ruth M; Fontinha, Bruno M; Kirchmaier, Stephan; Steger, Julia; Bloch, Susanne; Inoue, Daigo; Panda, Satchidananda; Rumpel, Simon; Tessmar-Raible, Kristin

2013-06-11

93

Co-Expression of VAL- and TMT-Opsins Uncovers Ancient Photosensory Interneurons and Motorneurons in the Vertebrate Brain  

PubMed Central

The functional principle of the vertebrate brain is often paralleled to a computer: information collected by dedicated devices is processed and integrated by interneuron circuits and leads to output. However, inter- and motorneurons present in today's vertebrate brains are thought to derive from neurons that combined sensory, integration, and motor function. Consistently, sensory inter­motorneurons have been found in the simple nerve nets of cnidarians, animals at the base of the evolutionary lineage. We show that light-sensory motorneurons and light-sensory interneurons are also present in the brains of vertebrates, challenging the paradigm that information processing and output circuitry in the central brain is shielded from direct environmental influences. We investigated two groups of nonvisual photopigments, VAL- and TMT-Opsins, in zebrafish and medaka fish; two teleost species from distinct habitats separated by over 300 million years of evolution. TMT-Opsin subclasses are specifically expressed not only in hypothalamic and thalamic deep brain photoreceptors, but also in interneurons and motorneurons with no known photoreceptive function, such as the typeXIV interneurons of the fish optic tectum. We further show that TMT-Opsins and Encephalopsin render neuronal cells light-sensitive. TMT-Opsins preferentially respond to blue light relative to rhodopsin, with subclass-specific response kinetics. We discovered that tmt-opsins co-express with val-opsins, known green light receptors, in distinct inter- and motorneurons. Finally, we show by electrophysiological recordings on isolated adult tectal slices that interneurons in the position of typeXIV neurons respond to light. Our work supports “sensory-inter-motorneurons” as ancient units for brain evolution. It also reveals that vertebrate inter- and motorneurons are endowed with an evolutionarily ancient, complex light-sensory ability that could be used to detect changes in ambient light spectra, possibly providing the endogenous equivalent to an optogenetic machinery.

Fischer, Ruth M.; Fontinha, Bruno M.; Kirchmaier, Stephan; Steger, Julia; Bloch, Susanne; Inoue, Daigo; Panda, Satchidananda; Rumpel, Simon; Tessmar-Raible, Kristin

2013-01-01

94

The spatial patterning of mouse cone opsin expression is regulated by BMP signaling through downstream effector COUP-TF nuclear receptors  

PubMed Central

Cone photopigments, known as opsins, are pivotal elements and the first detection module employed in color vision. In mice, cone photoreceptors are distributed throughout the retina, and S- and M-opsins have unique expression patterns in the retina with a gradient along the dorsoventral axis; however, the mechanisms regulating the spatial patterning of cone opsin expression have not been well documented. The purpose of this study was to define the mechanisms regulating the spatial patterning of cone opsin expression. By analyzing knockouts for bone morphogenetic protein (BMP) signaling, we found an essential role for BMP in forming cone opsin expression patterns in the retina; however, BMP signaling is activated only transiently in the dorsal half of the retina during early retinal development. Thus, BMP is not likely to play a direct role in opsin gene expression, which starts at a later stage of retinal development. We identified the chicken ovalbumin upstream promoter-transcription factor (COUP-TF) nuclear receptor as a link between BMP and opsin expression. BMP signaling is essential for the correct dorsoventral spatial expression of COUP-TFI and -TFII. Through gain- and loss-of-function analyses, we found that both COUP-TFI and -TFII are required to suppress S-opsin expression in the dorsal retina but that only COUP-TFI plays an essential role in suppressing M-opsin expression in the ventral retina. Based on these findings, we propose a new molecular cascade involving BMP and COUP-TFs that conveys dorsoventral information to direct the expression of cone opsins during retinal development.

Satoh, Shinya; Tang, Ke; Iida, Atsumi; Inoue, Mariko; Kodama, Tatsuhiko; Tsai, Sophia Y.; Tsai, Ming-Jer; Furuta, Yasuhide; Watanabe, Sumiko

2009-01-01

95

Divergent Selection on Opsins Drives Incipient Speciation in Lake Victoria Cichlids  

PubMed Central

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.

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

2006-01-01

96

Jellyfish vision starts with cAMP signaling mediated by opsin-Gs cascade  

PubMed Central

Light sensing starts with phototransduction in photoreceptor cells. The phototransduction cascade has diverged in different species, such as those mediated by transducin in vertebrate rods and cones, by Gq-type G protein in insect and molluscan rhabdomeric-type visual cells and vertebrate photosensitive retinal ganglion cells, and by Go-type G protein in scallop ciliary-type visual cells. Here, we investigated the phototransduction cascade of a prebilaterian box jellyfish, the most basal animal having eyes containing lens and ciliary-type visual cells similar to vertebrate eyes, to examine the similarity at the molecular level and to obtain an implication of the origin of the vertebrate phototransduction cascade. We showed that the opsin-based pigment functions as a green-sensitive visual pigment and triggers the Gs-type G protein-mediated phototransduction cascade in the ciliary-type visual cells of the box jellyfish lens eyes. We also demonstrated the light-dependent cAMP increase in the jellyfish visual cells and HEK293S cells expressing the jellyfish opsin. The first identified prebilaterian cascade was distinct from known phototransduction cascades but exhibited significant partial similarity with those in vertebrate and molluscan ciliary-type visual cells, because all involved cyclic nucleotide signaling. These similarities imply a monophyletic origin of ciliary phototransduction cascades distributed from prebilaterian to vertebrate.

Koyanagi, Mitsumasa; Takano, Kosuke; Tsukamoto, Hisao; Ohtsu, Kohzoh; Tokunaga, Fumio; Terakita, Akihisa

2008-01-01

97

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.

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

98

Phylogenetic utility of the major opsin in bees (Hymenoptera: Apoidea): a reassessment.  

PubMed

Major opsin (LW Rh) DNA sequence has been reported to provide useful data for resolving phylogenetic relationships among tribes of corbiculate bees based on analyses of 502 bp of coding sequence. However, the corbiculate tribes are believed to be of Cretaceous age, and strong support for insect clades of this age from small data sets of nucleotide sequence data has rarely been demonstrated. To more critically assess opsin's phylogenetic utility we generated an expanded LW Rh data set by sequencing the same gene fragment from 52 additional bee species from 24 tribes and all six extant bee families. Analyses of this data set failed to provide substantial support for monophyly of corbiculate bees, for relationships among corbiculate tribes, or for most other well-established higher-level relationships among long-tongued bees. However, monophyly of nearly all genera and tribes is strongly supported, indicating that LW Rh provides useful phylogenetic signal at lower taxonomic levels. When our expanded LW Rh data set is combined with a morphological and behavioral data set for corbiculate bees, the results unambiguously support the traditional phylogeny of the corbiculate bee tribes: (Euglossini + (Bombini + (Meliponini + Apini))). This implies a single origin of advanced eusocial behavior among bees rather than dual origins, as proposed by several recent studies. PMID:11286493

Ascher, J S; Danforth, B N; Ji, S

2001-04-01

99

Diel changes in the expression of long wavelength-sensitive and ultraviolet-sensitive opsin genes in the Japanese firefly, Luciola cruciata.  

PubMed

Sexual communication between male and female fireflies involves the visual detection of bioluminescence. In the present study, we isolated two different types of opsin cDNAs from an adult of the Japanese firefly, Luciola cruciata. Phylogenetic analysis indicated that these genes correspond to long wavelength-sensitive and ultraviolet-sensitive opsins. This is in agreement with the prior findings, in which the spectral sensitivity of the L. cruciata eye showed two peaks, UV and long wavelength, and the latter substantially matched the bioluminescent spectrum of lambdamax=560 nm. Diel changes in both opsins mRNA levels were determined by quantitative PCR analysis. In adult females, the mRNA level of long wavelength-sensitive opsin was higher at night than in the day, and peaked at 20:00, the time when the luminescence behavior was most active. On the other hand, the expression level of ultraviolet-sensitive opsin was not significantly changed during the day. In adult males, diel changes in the expression of both opsins were not significant. The results suggest that the expression level of "bioluminescence-sensitive" opsins in female L. cruciata is linked to their mating behavior. PMID:19232386

Oba, Yuichi; Kainuma, Takahiko

2009-02-13

100

Activation of mislocalized opsin kills rod cells: A novel mechanism for rod cell death in retinal disease  

PubMed Central

Rod photoreceptors are highly compartmentalized sensory neurons that maintain strict ultrastructural and molecular polarity. Structural subdivisions include the outer segment, inner segment, cell body, and synaptic terminal. The visual pigment rhodopsin is found predominantly in membranes of the rod cell outer segment but becomes mislocalized, appearing throughout the plasma membrane of the cell in many retinal diseases and injuries. Currently, there is no known link between rhodopsin redistribution and rod cell death. We propose that activation of mislocalized rhodopsin kills rod cells by stimulating normally inaccessible signaling pathways. This hypothesis was tested in primary retinal cell cultures, which contain photoreceptors. In rod photoreceptors, opsin immunofluorescence occurred throughout the rod cell plasma membrane. Activation of this mislocalized opsin by photostimulation after formation of isorhodopsin or by incubation with ?-ionone (opsin agonist) killed 19–30% of rod cells. Rod cell death was apoptotic, as indicated by marked chromatin condensation and the requirement for caspase-3 activation. Rod cell death could be induced by forskolin (adenylate cyclase agonist), and conversely, ?-ionone-induced cell death could be blocked by cotreatment with SQ22536 (an adenylate cyclase inhibitor). Pertussis toxin (a G protein inhibitor) also blocked ?-ionone-induced cell death. The data support a mechanism by which activation of mislocalized opsin initiates apoptotic rod cell death through G protein stimulation of adenylate cyclase.

Alfinito, Peter D.; Townes-Anderson, Ellen

2002-01-01

101

Evolution of color vision in pierid butterflies: blue opsin duplication, ommatidial heterogeneity and eye regionalization in Colias erate.  

PubMed

This paper documents the molecular organization of the eye of the Eastern Pale Clouded Yellow butterfly, Colias erate (Pieridae). We cloned four cDNAs encoding visual pigment opsins, corresponding to one ultraviolet, two blue and one long wavelength-absorbing visual pigments. Duplication of the blue visual pigment class occurs also in another pierid species, Pieris rapae, suggesting that blue duplication is a general feature in the family Pieridae. We localized the opsin mRNAs in the Colias retina by in situ hybridization. Among the nine photoreceptor cells in an ommatidium, R1-9, we found that R3-8 expressed the long wavelength class mRNA in all ommatidia. R1 and R2 expressed mRNAs of the short wavelength opsins in three fixed combinations, corresponding to three types of ommatidia. While the duplicated blue opsins in Pieris are separately expressed in two subsets of R1-2 photoreceptors, one blue sensitive and another violet sensitive, those of Colias appear to be always coexpressed. PMID:19224222

Awata, Hiroko; Wakakuwa, Motohiro; Arikawa, Kentaro

2009-02-18

102

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.

2013-01-01

103

Genomic organization, evolution, and expression of photoprotein and opsin genes in Mnemiopsis leidyi: a new view of ctenophore photocytes  

PubMed Central

Background Calcium-activated photoproteins are luciferase variants found in photocyte cells of bioluminescent jellyfish (Phylum Cnidaria) and comb jellies (Phylum Ctenophora). The complete genomic sequence from the ctenophore Mnemiopsis leidyi, a representative of the earliest branch of animals that emit light, provided an opportunity to examine the genome of an organism that uses this class of luciferase for bioluminescence and to look for genes involved in light reception. To determine when photoprotein genes first arose, we examined the genomic sequence from other early-branching taxa. We combined our genomic survey with gene trees, developmental expression patterns, and functional protein assays of photoproteins and opsins to provide a comprehensive view of light production and light reception in Mnemiopsis. Results The Mnemiopsis genome has 10 full-length photoprotein genes situated within two genomic clusters with high sequence conservation that are maintained due to strong purifying selection and concerted evolution. Photoprotein-like genes were also identified in the genomes of the non-luminescent sponge Amphimedon queenslandica and the non-luminescent cnidarian Nematostella vectensis, and phylogenomic analysis demonstrated that photoprotein genes arose at the base of all animals. Photoprotein gene expression in Mnemiopsis embryos begins during gastrulation in migrating precursors to photocytes and persists throughout development in the canals where photocytes reside. We identified three putative opsin genes in the Mnemiopsis genome and show that they do not group with well-known bilaterian opsin subfamilies. Interestingly, photoprotein transcripts are co-expressed with two of the putative opsins in developing photocytes. Opsin expression is also seen in the apical sensory organ. We present evidence that one opsin functions as a photopigment in vitro, absorbing light at wavelengths that overlap with peak photoprotein light emission, raising the hypothesis that light production and light reception may be functionally connected in ctenophore photocytes. We also present genomic evidence of a complete ciliary phototransduction cascade in Mnemiopsis. Conclusions This study elucidates the genomic organization, evolutionary history, and developmental expression of photoprotein and opsin genes in the ctenophore Mnemiopsis leidyi, introduces a novel dual role for ctenophore photocytes in both bioluminescence and phototransduction, and raises the possibility that light production and light reception are linked in this early-branching non-bilaterian animal.

2012-01-01

104

Mislocalized Opsin and cAMP Signaling: A Mechanism for Sprouting by Rod Cells in Retinal Degeneration  

PubMed Central

Purpose. In human retinal degeneration, rod photoreceptors reactively sprout neurites. The mechanism is unknown in part because of the paucity of animal models displaying this feature of human pathology. We tested the role of cAMP and opsin in sprouting by tiger salamander rod cells, photoreceptors that can produce reactive growth. Methods. In vitro systems of isolated photoreceptor cells and intact neural retina were used. cAMP signaling was manipulated with nucleotide analogues, enzyme stimulators, agonists for adenosine and dopamine receptors, and the opsin agonist, ?-ionone. Levels of cAMP were determined by radioimmunoassay, and protein levels by Western blot and quantitative immunocytochemistry. Neuritic growth was assayed by image analysis and conventional and confocal microscopy. Results. cAMP analogues and stimulation of adenylyl cyclase (AC) directly or through G-protein–coupled receptors resulted in significant increases in neuritic growth of isolated rod, but not cone, cells. The signaling pathway included protein kinase A (PKA) and phosphorylation of the transcription factor cAMP response element-binding protein (pCREB). Opsin, a G-linked receptor, is present throughout the plasmalemma of isolated cells; its activation also induced sprouting. In neural retina, rod sprouting was significantly increased by ?-ionone with concomitant increases in cAMP, pCREB, and synaptic proteins. Notably, opsin stimulated sprouting only when mislocalized to the plasmalemma of the rod cell body. Conclusions. cAMP causes neuritic sprouting in rod, but not cone, cells through the AC-PKA-CREB pathway known to be associated with synaptic plasticity. We propose that in retinal disease, mislocalized rod opsin gains access to cAMP signaling, which leads to neuritic sprouting.

Wang, Jianfeng; Zhang, Nan; Beuve, Annie; Townes-Anderson, Ellen

2012-01-01

105

A non-mammalian type opsin 5 functions dually in the photoreceptive and non-photoreceptive organs of birds.  

PubMed

A mammalian type opsin 5 (neuropsin) is a recently identified ultraviolet (UV)-sensitive pigment of the retina and other photosensitive organs in birds. Two other opsin 5-related molecules have been found in the genomes of non-mammalian vertebrates. However, their functions have not been examined as yet. Here, we identify the molecular properties of a second avian opsin 5, cOpn5L2 (chicken opsin 5-like 2), and its localization in the post-hatch chicken. Spectrophotometric analysis and radionucleotide-binding assay have revealed that cOpn5L2 is a UV-sensitive bistable pigment that couples with the Gi subtype of guanine nucleotide-binding protein (G protein). As a bistable pigment, it also shows the direct binding ability to agonist all-trans-retinal to activate G protein. The absorption maxima of UV-light-absorbing and visible light-absorbing forms were 350 and 521 nm, respectively. Expression analysis showed relatively high expression of cOpn5L2 mRNA in the adrenal gland, which is not photoreceptive but an endocrine organ, while lower expression was found in the brain and retina. At the protein level, cOpn5L2 immunoreactive cells were present in the chromaffin cells of the adrenal gland. In the brain, cOpn5L2 immunoreactive cells were found in the paraventricular and supraoptic nuclei of the anterior hypothalamus, known for photoreceptive deep brain areas. In the retina, cOpn5L2 protein was localized to subsets of cells in the ganglion cell layer and the inner nuclear layer. These results suggest that the non-mammalian type opsin 5 (Opn5L2) functions as a second UV sensor in the photoreceptive organs, while it might function as chemosensor using its direct binding ability to agonist all-trans-retinal in non-photoreceptive organs such as the adrenal gland of birds. PMID:22348098

Ohuchi, Hideyo; Yamashita, Takahiro; Tomonari, Sayuri; Fujita-Yanagibayashi, Sari; Sakai, Kazumi; Noji, Sumihare; Shichida, Yoshinori

2012-02-14

106

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

Robinson, P R; Buczylko, J; Ohguro, H; Palczewski, K

1994-01-01

107

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

PubMed

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

2013-10-31

108

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.

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

2013-01-01

109

Mapping the Moho with seismic surface waves: Sensitivity, resolution, and recommended inversion strategies  

NASA Astrophysics Data System (ADS)

Seismic surface waves have been used to study the Earth's crust since the early days of modern seismology. In the last decade, surface-wave crustal imaging has been rejuvenated by the emergence of new, array techniques (ambient-noise and teleseismic interferometry). The strong sensitivity of both Rayleigh and Love waves to the Moho is evident from a mere visual inspection of their dispersion curves or waveforms. Yet, strong trade-offs between the Moho depth and crustal and mantle structure in surface-wave inversions have prompted doubts regarding their capacity to resolve the Moho. Although the Moho depth has been an inversion parameter in numerous surface-wave studies, the resolution of Moho properties yielded by a surface-wave inversion is still somewhat uncertain and controversial. We use model-space mapping in order to elucidate surface waves' sensitivity to the Moho depth and the resolution of their inversion for it. If seismic wavespeeds within the crust and upper mantle are known, then Moho-depth variations of a few kilometres produce large (over 1 per cent) perturbations in phase velocities. However, in inversions of surface-wave data with no a priori information (wavespeeds not known), strong Moho-depth/shear-speed trade-offs will mask about 90 per cent of the Moho-depth signal, with remaining phase-velocity perturbations 0.1-0.2 per cent only. In order to resolve the Moho with surface waves alone, errors in the data must thus be small (up to 0.2 per cent for resolving continental Moho). If the errors are larger, Moho-depth resolution is not warranted and depends on error distribution with period, with errors that persist over broad period ranges particularly damaging. An effective strategy for the inversion of surface-wave data alone for the Moho depth is to, first, constrain the crustal and upper-mantle structure by inversion in a broad period range and then determine the Moho depth in inversion in a narrow period range most sensitive to it, with the first-step results used as reference. We illustrate this strategy with an application to data from the Kaapvaal Craton. Prior information on crustal and mantle structure reduces the trade-offs and thus enables resolving the Moho depth with noisier data; such information should be sought and used whenever available (as has been done, explicitly or implicitly, in many previous studies). Joint analysis or inversion of surface-wave and other data (receiver functions, topography, gravity) can reduce uncertainties further and facilitate Moho mapping. Alone or as a part of multi-disciplinary datasets, surface-wave data offer unique sensitivity to the crustal and upper-mantle structure and are becoming increasingly important in the seismic imaging of the crust and the Moho. Reference Lebedev, S., J. Adam, T. Meier. Mapping the Moho with seismic surface waves: A review, resolution analysis, and recommended inversion strategies. Tectonophysics, "Moho" special issue, 10.1016/j.tecto.2012.12.030, 2013.

Lebedev, Sergei; Adam, Joanne; Meier, Thomas

2013-04-01

110

The Human Blue Opsin Promoter Directs Transgene Expression in Short-Wave Cones and Bipolar Cells in the Mouse Retina  

Microsoft Academic Search

Transgenic mouse lines were generated using either 3.8 or 1.1 kb of 5' upstream flanking sequence from the human blue opsin gene fused to the lacZ or human growth hormone reporter gene. Mice were analyzed for appropriate cell-specific and developmental expression patterns. In 13 independently derived lines of animals, transgene expression was limited to photoreceptor and inner nuclear layer cells.

J. Chen; C. L. Tucker; B. Woodford; A. Szel; J. Lem; A. Gianella-Borradori; M. I. Simon; E. Bogenmann

1994-01-01

111

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

Microsoft Academic Search

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

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

2009-01-01

112

Effect of transmembrane helix packing on tryptophan and tyrosine environments in detergent-solubilized bacterio-opsin  

Microsoft Academic Search

Bacterio-opsin (bO) is folded in a nearly native conformation in mixed micelles of dimyristoyl phosphatidyl choline (DMPC) and 3-[(3-cholamidopropyl)-dimehtylamonio]-1-propane sulfonic acid (CHAPS), but bO is partially unfolded in sodium dodecyl sulfate (SDS). UV difference spectroscopy was used to study the changes in environment of bO aromatic amino acid side chains that occur upon partial unfolding. The UV difference spectra of

Robert Renthal; Patrick Haas

1996-01-01

113

The archaebacterial membrane protein bacterio-opsin is expressed and N-terminally processed in the yeast Saccharomyces cerevisiae  

Microsoft Academic Search

The bop gene codes for the membrane protein bacterio-opsin (BO), which on binding all-trans-retinal, constitutes the light-driven proton pump bacteriorhodopsin (BR) in the archaebacterium Halobacterium salinariumThe designation H. salinarium instead of the former designation H. halobium is used throughout this paper following the classification of Tindall (1992). This gene was cloned in a yeast multi-copy vector and expressed in Saccharomyces

Christine Lang-HinrichsIngo; Ingo Queck; Georg Büldt; Ulf Stahl; Volker Hildebrandt

1994-01-01

114

Sea urchin tube feet are photosensory organs that express a rhabdomeric-like opsin and PAX6  

PubMed Central

All echinoderms have unique hydraulic structures called tube feet, known for their roles in light sensitivity, respiration, chemoreception and locomotion. In the green sea urchin, the most distal portion of these tube feet contain five ossicles arranged as a light collector with its concave surface facing towards the ambient light. These ossicles are perforated and lined with pigment cells that express a PAX6 protein that is universally involved in the development of eyes and sensory organs in other bilaterians. Polymerase chain reaction (PCR)-based sequencing and real time quantitative PCR (qPCR) also demonstrate the presence and differential expression of a rhabdomeric-like opsin within these tube feet. Morphologically, nerves that could serve to transmit information to the test innervate the tube feet, and the differential expression of opsin transcripts in the tube feet is inversely, and significantly, related to the amount of light that tube feet are exposed to depending on their location on the test. The expression of these genes, the differential expression of opsin based on light exposure and the unique morphological features at the distal portion of the tube foot strongly support the hypothesis that in addition to previously identified functional roles of tube feet they are also photosensory organs that detect and respond to changes in the underwater light field.

Lesser, Michael P.; Carleton, Karen L.; Bottger, Stefanie A.; Barry, Thomas M.; Walker, Charles W.

2011-01-01

115

Gene Duplication and Spectral Diversification of Cone Visual Pigments of Zebrafish  

Microsoft Academic Search

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,

Akito Chinen; Takanori Hamaoka; Yukihiro Yamada; Shoji Kawamura

2003-01-01

116

Homologous bacterio-opsin-encoding gene expression via site-specific vector integration.  

PubMed

Homologous recombination in the archaebacterium Halobacterium halobium has been investigated and exploited for the wild-type (wt) level of expression of the bacterio-opsin-encoding gene (bop). The Haloferax volcanii-Escherichia coli shuttle vector, pWL102, was used to construct a shuttle-mutagenesis vector, pEF191, bearing bop and short flanking sequences. Transformation of a bacteriorhodopsin (BR)-negative H. halobium strain with pEF191 resulted in plasmid integration at the homologous bop locus. A model for this site-specific vector integration is presented which has been confirmed by determining the arrangement of the repeated homologous sequences on the chromosome. Two different configurations are obtained after integrative transformation due to the presence of an insertion element in the genomic copy of bop. In one configuration, the functional bop cluster containing the regulatory bat and brp genes was in wt arrangement. In the second configuration, the bop cluster is interrupted by 10 kb of plasmid vector sequences, and the upstream region required for bop expression was limited to 400 bp. The BR production for both configurations was determined and found to be at wt level. These results suggest that the function of the putative bop promoter does not depend on the defined upstream positions of bat and brp. The system presented here can be easily exploited for structure-function studies on BR and introduces homologous gene targeting as a powerful tool in the study of halobacterial genetics. PMID:8383625

Ferrando, E; Schweiger, U; Oesterhelt, D

1993-03-15

117

Spectral tuning and evolution of short wave-sensitive cone pigments in cottoid fish from Lake Baikal.  

PubMed

The cottoid fishes of Lake Baikal in eastern Siberia provide a unique opportunity to study the evolution of visual pigments in a group of closely related species exposed to different photic environments. Members of this species flock are adapted to different depth habitats down to >1000 m, and both the rod and cone visual pigments display short wave shifts as depth increases. The blue-sensitive cone pigments of the SWS2 class cluster into two species groups with lambda(max) values of 450 and 430 nm, with the pigment in Cottus gobio, a cottoid fish native to Britain, forming a third group with a lambda(max) of 467 nm. The sequences of the SWS2 opsin gene from C. gobio and from two representatives of the 450 and 430 nm Baikal groups are presented. Approximately 6 nm of the spectral difference between C. gobio and the 450 nm Baikal group can be ascribed to the presence of a porphyropsin/rhodopin mixture in C. gobio. Subsequent analysis of amino acid substitutions by site-directed mutagenesis demonstrates that the remainder of the shift from 461 to 450 nm arises from a Thr269Ala substitution and the shift from 450 to 430 nm at least partly from Thr118Ala and Thr118Gly substitutions. The underlying adaptive significance of these substitutions in terms of spectral tuning and signal-to-noise ratio is discussed. PMID:11993996

Cowing, Jill A; Poopalasundaram, Subathra; Wilkie, Susan E; Bowmaker, James K; Hunt, David M

2002-05-14

118

Analysis of the Promoter of the ninaE Opsin Gene in Drosophila melanogaster  

PubMed Central

We have analyzed the cis-acting regulatory sequences of the ninaE gene. This gene encodes the major Drosophila melanogaster opsin, the protein component of the primary chromophore of photoreceptor cells R1–R6 of the adult eye. DNA fragments containing the start point of transcription of the ninaE gene were fused to either the Escherichia coli chloramphenicol acetyltransferase or lacZ (?-galactosidase) gene and introduced into the Drosophila germline by P-element-mediated transformation. Expression of the E. coli genes was then used to assay the ability of various sequences from the ninaE gene to confer the ninaE pattern of expression. Fragments containing between 2.8 kb and 215 bp of the sequences upstream of the start of transcription plus the first 67 bp of the untranslated leader were able to direct nearly wild-type expression. We have identified three separable control regions in the ninaE promoter. The first, which has the properties of an enhancer element, is located between nucleotides -501 and -219. The removal of this sequence had little effect on promoter function; this sequence appears to be redundant. However, it appears to be able to substitute for the second control region which is located between nucleotides -215 and -162, and which also affects the level of output from this promoter. Removal of these two control regions resulted in a 30-fold decrease in expression; however tissue specificity was not affected. The third control region, located downstream from nucleotide -120, appears to be absolutely necessary for promoter function in the absence of the first two regulatory sequences. Examination of larvae containing fusion genes expressing ?-galactosidase suggests that the ninaE gene is also expressed in a subset of cells in the larval photoreceptor organ.

Mismer, Drzislav; Rubin, Gerald M.

1987-01-01

119

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.

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

2012-01-01

120

Nocturnal light environments influence color vision and signatures of selection on the OPN1SW opsin gene in nocturnal lemurs.  

PubMed

Although loss of short-wavelength-sensitive (SWS) cones and dichromatic color vision in mammals has traditionally been linked to a nocturnal lifestyle, recent studies have identified variation in selective pressure for the maintenance of the OPN1SW opsin gene (and thus, potentially dichromacy) among nocturnal mammalian lineages. These studies hypothesize that purifying selection to retain SWS cones may be associated with a selective advantage for nocturnal color vision under certain ecological conditions. In this study, we explore the effect of nocturnal light environment on OPN1SW opsin gene evolution in a diverse sample of nocturnal lemurs (106 individuals, 19 species, and 5 genera). Using both phylogenetic and population genetic approaches, we test whether species from closed canopy rainforests, which are impoverished in short-wavelength light, have experienced relaxed selection compared with species from open canopy forests. We identify clear signatures of differential selection on OPN1SW by habitat type. Our results suggest that open canopy species generally experience strong purifying selection to maintain SWS cones. In contrast, closed canopy species experience weaker purifying selection or a relaxation of selection on OPN1SW. We also found evidence of nonfunctional OPN1SW genes in all Phaner species and in Cheirogaleus medius, implying at least three independent losses of SWS cones in cheirogaleids. Our results suggest that the evolution of color vision in nocturnal lemurs has been influenced by nocturnal light environment. PMID:23519316

Veilleux, Carrie C; Louis, Edward E; Bolnick, Deborah A

2013-03-21

121

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

PubMed

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

2013-08-05

122

The influence of ontogeny and light environment on the expression of visual pigment opsins in the retina of the black bream, Acanthopagrus butcheri  

Microsoft Academic Search

SUMMARY The correlation between ontogenetic changes in the spectral absorption characteristics of retinal photoreceptors and expression of visual pigment opsins was investigated in the black bream, Acanthopagrus butcheri. To establish whether the spectral qualities of environmental light affected the complement of visual pigments during ontogeny, comparisons were made between fishes reared in: (1) broad spectrum aquarium conditions; (2) short wavelength-reduced

Julia Shand; Wayne L. Davies; Nicole Thomas; Lois Balmer; Jill A. Cowing; Marie Pointer; Livia S. Carvalho; Ann E. O. Trezise; Shaun P. Collin; Lyn D. Beazley; David M. Hunt

2008-01-01

123

Evolution of phototransduction, vertebrate photoreceptors and retina.  

PubMed

Evidence is reviewed from a wide range of studies relevant to the evolution of vertebrate photoreceptors and phototransduction, in order to permit the synthesis of a scenario for the major steps that occurred during the evolution of cones, rods and the vertebrate retina. The ancestral opsin originated more than 700 Mya (million years ago) and duplicated to form three branches before cnidarians diverged from our own lineage. During chordate evolution, ciliary opsins (C-opsins) underwent multiple stages of improvement, giving rise to the 'bleaching' opsins that characterise cones and rods. Prior to the '2R' rounds of whole genome duplication near the base of the vertebrate lineage, 'cone' photoreceptors already existed; they possessed a transduction cascade essentially the same as in modern cones, along with two classes of opsin: SWS and LWS (short- and long-wave-sensitive). These cones appear to have made synaptic contact directly onto ganglion cells, in a two-layered retina that resembled the pineal organ of extant non-mammalian vertebrates. Interestingly, those ganglion cells appear to be descendants of microvillar photoreceptor cells. No lens was associated with this two-layered retina, and it is likely to have mediated circadian timing rather than spatial vision. Subsequently, retinal bipolar cells evolved, as variants of ciliary photoreceptors, and greatly increased the computational power of the retina. With the advent of a lens and extraocular muscles, spatial imaging information became available for central processing, and gave rise to vision in vertebrates more than 500 Mya. The '2R' genome duplications permitted the refinement of cascade components suitable for both rods and cones, and also led to the emergence of five visual opsins. The exact timing of the emergence of 'true rods' is not yet clear, but it may not have occurred until after the divergence of jawed and jawless vertebrates. PMID:23792002

Lamb, Trevor D

2013-06-19

124

Photoreceptors for a light biotransducer: a comparative study of the electrical responses of two (type-1) opsins  

NASA Astrophysics Data System (ADS)

The increasing interest in photoactivated proteins as natural replacements for standard inorganic materials in photocells leads to the comparison analysis of bacteriorhodopsin and proteorhodopsin, two widely diffused proteins belonging to the family of type-1 opsins. These proteins share similar behaviors but exhibit relevant differences in the sequential chain of the amino acids constituting their tertiary structure. The use of an impedance network analog to model the protein main features provides a microscopic interpretation of a set of experiments on their photo-conductance properties. In particular, this model links the protein electrical responses to the tertiary structure and to the interactions between neighboring amino acids. The same model is also used to predict the small-signal response in terms of the Nyquist plot. Interestingly, these rhodopsins are found to behave like a wide-gap semiconductor with intrinsic conductivities of the order of 10?7 S cm?1.

Alfinito, E.; Pousset, J.; Reggiani, L.; Lee, K.

2013-10-01

125

Photoreceptors for a light biotransducer: a comparative study of the electrical responses of two (type-1) opsins.  

PubMed

The increasing interest in photoactivated proteins as natural replacements for standard inorganic materials in photocells leads to the comparison analysis of bacteriorhodopsin and proteorhodopsin, two widely diffused proteins belonging to the family of type-1 opsins. These proteins share similar behaviors but exhibit relevant differences in the sequential chain of the amino acids constituting their tertiary structure. The use of an impedance network analog to model the protein main features provides a microscopic interpretation of a set of experiments on their photo-conductance properties. In particular, this model links the protein electrical responses to the tertiary structure and to the interactions between neighboring amino acids. The same model is also used to predict the small-signal response in terms of the Nyquist plot. Interestingly, these rhodopsins are found to behave like a wide-gap semiconductor with intrinsic conductivities of the order of 10(-7) S cm(-1). PMID:24013479

Alfinito, E; Pousset, J; Reggiani, L; Lee, K

2013-09-06

126

Genetic transformation of Rangpur lime (Citrus limonia osbeck) with thebO (bacterio-opsin) genen and its initial evaluation forPhytophthora nicotianae resistance  

Microsoft Academic Search

Transgenic plants expressing the bacterio-opsin (bO) gene can spontaneously activate programmed cell death (pcd) and may enhance broad-spectrum pathogen resistance by activating an intrinsic defense pathway in plant species such as tobacco and potato. In this work, we produced transgenic Rangpur lime plants with the bO gene, via Agro- bacterium tumefaciens-mediated transformation, and evaluated these plants for Phyto- phthora nicotianae

F. A. Azevedo; F. A. A. Mourão Filho; B. M. J. Mendes; W. A. B. Almeida; E. H. Schinor; R. Pio; J. M. Barbosa; S. GUIDETTI-GONZALEZ; H. Carrer; E. Lam

2006-01-01

127

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

2012-03-16

128

Physiology and morphology of color-opponent ganglion cells in a retina expressing a dual gradient of S and M opsins  

PubMed Central

Most mammals are dichromats, having short-wavelength sensitive (S) and middle-wavelength sensitive (M) cones. Smaller terrestrial species commonly express a dual gradient in opsins, with M opsin concentrated superiorly and declining inferiorly, and vice-versa for S opsin. Some ganglion cells in these retinas combine S and M-cone inputs antagonistically, but no direct evidence links this physiological opponency with morphology; nor is it known whether opponency varies with the opsin gradients. By recording from more than 3000 ganglion cells in guinea pig, we identified small numbers of color-opponent cells. Chromatic properties were characterized by responses to monochromatic spots and/or spots produced by mixtures of two primary lights. Superior retina contained cells with strong S+/M? and M+/S? opponency, whereas inferior retina contained cells with weak opponency. In superior retina, the opponent cells had well-balanced M and S weights, while in inferior retina the weights were unbalanced, with the M weights being much weaker. The M and S components of opponent cell receptive fields had approximately the same diameter. Opponent cells injected with Lucifer yellow restricted their dendrites to the ON stratum of the inner plexiform layer and provided sufficient membrane area (?2.1e+4 ?m2) to collect ?3.9e+3 bipolar synapses. Two bistratified cells studied were non-opponent. The apparent decline in S/M opponency from superior to inferior retina is consistent with the dual gradient and a model where photoreceptor signals in both superior and inferior retina are processed by the same post-receptoral circuitry.

Yin, Lu; Smith, Robert G; Sterling, Peter; Brainard, David H.

2009-01-01

129

Eyeshine and spectral tuning of long wavelength-sensitive rhodopsins: no evidence for red-sensitive photoreceptors among five Nymphalini butterfly species.  

PubMed

Spectral tuning of rhodopsins commonly refers to the effects of opsin amino acid substitutions on the wavelength for peak sensitivity of the rhodopsin absorption spectrum. Nymphalini butterflies provide an opportunity for identifying some of the amino acid substitutions responsible for insect rhodopsin spectral tuning because the majority of photoreceptor cells (R3-9) in the adult retina express only a single long wavelength-sensitive (LWS) opsin mRNA transcript. Therefore, the opsin genotype can be directly correlated with its phenotype. We determined the LWS opsin gene sequence from cDNA of the mourning cloak Nymphalis antiopa, and from genomic DNA of the malachite Siproeta stelenes and the peacock Inachis io. Using an epi-microspectrophotometer we examined each butterfly's eyeshine for photochemical evidence of multiple LWS rhodopsins and found only one. We then performed partial-bleaching experiments to obtain absorbance spectra for the LWS rhodopsins of all three species as well as from another nymphalid, the buckeye Junonia coenia. The isolated LWS opsin gene sequences varied in length from 1437-1612 bp and encode rhodopsins R522 (S. stelenes), R530 (I. io), R534 (N. antiopa) and, together with a previously published sequence, R510 (J. coenia). Comparative sequence analysis indicates that the S. stelenes rhodopsin is slightly blue-shifted compared to the typical 530 nm lepidopteran rhodopsin because of the presence of a S138A substitution at a homologous site that in mammalian MWS/LWS rhodopsins causes a 5 nm blue-shift. The difference in peak absorption between R522 of S. stelenes and R530 of Inachis io is therefore largely accounted for by this substitution. This suggests that spectral tuning mechanisms employing the S138A may have evolved in parallel in mammalian and butterfly MWS/LWS rhodopsins across 500 million years of evolution. PMID:15695761

Briscoe, Adriana D; Bernard, Gary D

2005-02-01

130

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.

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

2000-01-01

131

ISO Guest Observer Data Analysis and LWS Instrument Team Activities  

NASA Astrophysics Data System (ADS)

This project was granted a no-cost extension prompted by the request of the major subcontractor, the Naval Research Laboratory, which had not yet completed its tasks. As of July 2002, they had made substantial progress. They have successfully fabricated a metal mesh grid on polyimide, and also successfully fabricated a 2-layer metal mesh infrared filter using stacks of these metal mesh grids on polyimide; the actual layering was done at SAO. Both warm and cold spectroscopic tests were done on these fabricated devices. The measurements were in good agreement with the theory, and also reasonable performance in absolute terms. NRL is now working on fabricating a 3-layer metal mesh infrared filter, and a prototype is expected in the next month. Testing should occur before the end of the fiscal year. Finally, NRL has preliminarily agreed to hire a new postdoctoral person to refine the modeling of the filters based on the new measurements. The person should arrive this fall. NRL has a new Fourier Transform Spectrometer which will be delivered in the next month, and which will be used to facilitate the testing which has up to now been done in collaboration with NASA Goddard Space Flight Space Center.

Smith, Howard

2002-08-01

132

The visual pigments of the West Indian manatee (Trichechus manatus).  

PubMed

Manatees are unique among the fully aquatic marine mammals in that they are herbivorous creatures, with hunting strategies restricted to grazing on sea-grasses. Since the other groups of (carnivorous) marine mammals have been found to possess various visual system adaptations to their unique visual environments, it was of interest to investigate the visual capability of the manatee. Previous work, both behavioral (Griebel & Schmid, 1996), and ultrastructural (Cohen, Tucker, & Odell, 1982; unpublished work cited by Griebel & Peichl, 2003), has suggested that manatees have the dichromatic color vision typical of diurnal mammals. This study uses molecular techniques to investigate the cone visual pigments of the manatee. The aim was to clone and sequence cone opsins from the retina, and, if possible, express and reconstitute functional visual pigments to perform spectral analysis. Both LWS and SWS cone opsins were cloned and sequenced from manatee retinae, which, upon expression and spectral analysis, had lambda(max) values of 555 and 410 nm, respectively. The expression of both the LWS and SWS cone opsin in the manatee retina is unique as both pinnipeds and cetaceans only express a cone LWS opsin. PMID:16650454

Newman, Lucy A; Robinson, Phyllis R

2006-05-02

133

Cone visual pigments of monotremes: filling the phylogenetic gap.  

PubMed

We have determined the sequence and genomic organization of the genes encoding the cone visual pigment of the platypus (Ornithorhynchus anatinus) and the echidna (Tachyglossus aculeatus), and inferred their spectral properties and evolutionary pathways. We prepared platypus and echidna retinal RNA and used primers of the middle-wave-sensitive (MWS), long-wave-sensitive (LWS), and short-wave sensitive (SWS1) pigments corresponding to coding sequences that are highly conserved among mammals; to PCR amplify the corresponding pigment sequences. Amplification from the retinal RNA revealed the expression of LWS pigment mRNA that is homologous in sequence and spectral properties to the primate LWS visual pigments. However, we were unable to amplify the mammalian SWS1 pigment from these two species, indicating this gene was lost prior to the echidna-platypus divergence (21 MYA). Subsequently, when the platypus genome sequence became available, we found an LWS pigment gene in a conserved genomic arrangement that resembles the primate pigment, but, surprisingly we found an adjacent (20 kb) SWS2 pigment gene within this conserved genomic arrangement. We obtained the same result after sequencing the echidna genes. The encoded SWS2 pigment is predicted to have a wavelength of maximal absorption of about 440 nm, and is paralogous to SWS pigments typically found in reptiles, birds, and fish but not in mammals. This study suggests the locus control region (LCR) has played an important role in the conservation of photo receptor gene arrays and the control of their spatial and temporal expression in the retina in all mammals. In conclusion, a duplication event of an ancestral cone visual pigment gene, followed by sequence divergence and selection gave rise to the LWS and SWS2 visual pigments. So far, the echidna and platypus are the only mammals that share the gene structure of the LWS-SWS2 pigment gene complex with reptiles, birds and fishes. PMID:18598396

Wakefield, Matthew J; Anderson, Mark; Chang, Ellen; Wei, Ke-Jun; Kaul, Rajinder; Graves, Jennifer A Marshall; Grützner, Frank; Deeb, Samir S

134

Surface wave sensitivity: mode summation versus adjoint SEM  

Microsoft Academic Search

We compare finite-frequency phase and amplitude sensitivity kernels calculated based on frequency-domain surface wave mode summation and a time-domain adjoint method. The adjoint calculations involve a forward wavefield generated by an earthquake and an adjoint wavefield generated at a seismic receiver. We determine adjoint sources corresponding to frequency-dependent phase and amplitude measurements made using a multitaper technique, which may be

Ying Zhou; Qinya Liu; Jeroen Tromp

2011-01-01

135

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

136

Evolution of SECAA's Services and Role to Support SEC Virtual Observatories and the Missions of LWS  

Microsoft Academic Search

The successful definition and implementation of a Virtual Observatory (VO) framework to be the future Sun-Earth Connection (SEC) \\/ Solar-Terrestrial data environment will enable a distributed and modular implementation but nonetheless increasingly integrated and transparent data view by end users. All important SEC science data must be easily accessible and scientifically usable, both for specialized studies and across the boundaries

R. E. McGuire; R. M. Candey; R. A. Chimiak; S. F. Fung; J. L. Green; D. B. Han; B. T. Harris; R. C. Johnson; R. L. Kessel; T. J. Kovalick; H. A. Leckner

2003-01-01

137

Demonstration of a genotype-phenotype correlation in the polymorphic color vision of a non-callitrichine New World monkey, capuchin (Cebus apella).  

PubMed

Color-vision polymorphism in New World monkeys occurs because of an allelic polymorphism of the single-copy red-green middle-to-long-wavelength-sensitive (M/LWS) opsin gene on the X chromosome. Because color-vision types can readily be estimated from allelic types of the M/LWS opsin gene, this polymorphic system offers researchers an excellent opportunity to study the association between vision and behavior. As a prerequisite for such studies, genetically determined color-vision types must be concordant with phenotypes determined directly by behavioral criteria (e.g., by a color discrimination test). However, such correlations between genotypes and phenotypes have been studied only for callitrichine species. Using genetic, electrophysiological, and behavioral approaches, we evaluated the color vision of brown capuchin monkeys (Cebus apella), a representative non-callitrichine model animal for physiology and behavior. Two allelic M/LWS opsins-P545 and P530-were identified in the studied captive population. Females had one or both of the alleles, and males had either one. The retinal sensitivity in P530 dichromats was short-wave shifted relative to that in P545 dichromats, whereas that in P530/P545 trichromats was between the two groups. In a discrimination task using Ishihara pseudo-isochromatic plates, P530/P545 trichromats were successful in discriminating stimuli that P530 and P545 dichromats were unable to discriminate. In a food-search task, P530/P545 trichromats were able to locate red targets among green distracters as quickly as among white distracters, whereas both types of dichromats took longer. These results demonstrate the mutual consistency between genotypes and phenotypes of color vision, and provide a solid genetic basis on which the ecology and evolution of color vision can be investigated. PMID:16342070

Saito, Atsuko; Kawamura, Shoji; Mikami, Akichika; Ueno, Yoshikazu; Hiramatsu, Chihiro; Koida, Kowa; Fujita, Kazuo; Kuroshima, Hika; Hasegawa, Toshikazu

2005-12-01

138

LWS Studies of Gamma Rays Produced in the Earth's Atmosphere by Cosmic Rays and Solar Energetic Particle Events  

NASA Astrophysics Data System (ADS)

We summarize a three-year study of atmospheric gamma-ray line measurements conducted under the Living With a Star program. The observations were made by instruments on three satellites: SMM, Yohkoh, and RHESSI. They detected the 511-keV positron annihilation line produced in electromagnetic showers and de- excitation lines from 14N at 728, 1635, 2313, 3890, and 5106 keV, and from 16O at 6129 keV, as well as spallation lines near 4440 keV from 12C and 11B produced by neutron and proton interactions on Earth's atmosphere. The SMM studies focused on the variation of the cosmic-ray produced lines as a function of magnetic rigidity and solar cycle modulation. We found that the power-law spectral index of the secondary neutrons was relatively constant for the range of times and rigidity intervals sampled. The Yohkoh and RHESSI studies focused on atmospheric gamma rays produced by solar energetic particles interacting in the Earth's atmosphere following flares on 2000 July 14 and 2002 April 21, respectively. The SEP spectra estimated using gamma-ray line ratios were of comparable hardness with the spectrum measured by SMM for the 1989 October 20 intense event, consistent with measurements in space. Improved cross sections for the production of the nuclear lines offer better estimates of the spectra of SEPs impacting the atmosphere. Since the early observations, RHESSI has observed several more SEP events producing detectable fluxes of atmospheric gamma rays. These include large particle events in 2003 October/November and 2005 January.

Murphy, R. J.; Share, G. H.; Kozlovsky, B. Z.

2006-12-01

139

The activation of directional stem cell motility by green light-emitting diode irradiation.  

PubMed

Light-emitting diode (LED) irradiation is potentially a photostimulator to manipulate cell behavior by opsin-triggered phototransduction and thermal energy supply in living cells. Directional stem cell motility is critical for the efficiency and specificity of stem cells in tissue repair. We explored that green LED (530 nm) irradiation directed the human orbital fat stem cells (OFSCs) to migrate away from the LED light source through activation of extracellular signal-regulated kinases (ERK)/MAP kinase/p38 signaling pathway. ERK inhibitor selectively abrogated light-driven OFSC migration. Phosphorylation of these kinases as well as green LED irradiation-induced cell migration was facilitated by increasing adenosine triphosphate (ATP) production in OFSCs after green LED exposure, and which was thermal stress-independent mechanism. OFSCs, which are multi-potent mesenchymal stem cells isolated from human orbital fat tissue, constitutionally express three opsins, i.e. retinal pigment epithelium-derived rhodopsin homolog (RRH), encephalopsin (OPN3) and short-wave-sensitive opsin 1 (OPN1SW). However, only two non-visual opsins, i.e. RRH and OPN3, served as photoreceptors response to green LED irradiation-induced OFSC migration. In conclusion, stem cells are sensitive to green LED irradiation-induced directional cell migration through activation of ERK signaling pathway via a wavelength-dependent phototransduction. PMID:23261211

Ong, Wei-Kee; Chen, How-Foo; Tsai, Cheng-Ting; Fu, Yun-Ju; Wong, Yi-Shan; Yen, Da-Jen; Chang, Tzu-Hao; Huang, Hsien-Da; Lee, Oscar Kuang-Sheng; Chien, Shu; Ho, Jennifer Hui-Chun

2012-12-20

140

Analysis of the Promoter of the Rh2 Opsin Gene in Drosophila Melanogaster  

PubMed Central

We have analyzed the cis-acting regulatory sequences of the Drosophila melanogaster Rh2 gene that encodes the protein component of a rhodopsin which is expressed in ocellar photoreceptor cells. DNA fragments containing the start point of transcription of the Rh2 gene were fused to either the Escherichia coli chloramphenicol acetyltransferase (CAT) or lacZ (?-galactosidase) genes and introduced into the Drosophila germline by P-element-mediated transformation. Expression of the E. coli genes was then used to assay the ability of various sequences from the Rh2 gene to confer upon the indicator genes the Rh2 pattern of expression. Fragments containing between 4.3 kb and 183 bp upstream of the start of transcription plus the first 32 bp of the 5'-untranslated leader were found to result in nearly identical levels of head-specific CAT expression. Deletion of Rh2 sequences distal to position -112 bp resulted in loss of detectable CAT expression from these Rh2/CAT fusion constructs. We have, therefore, defined a region essential for head-specific expression of the Rh2 gene to a region extending from -183 to -112. We have determined the DNA sequence of the Rh2 promoter from -448 to +32 and have found an 11-bp sequence which is also present in the upstream flanking sequences of two other photoreceptor-specific genes (ninaE and ninaC). By histochemical staining of ?-galactosidase expressed under the control of the Rh2 promoter and by analyzing the effect of the ocelliless mutation on the expression of an Rh2/CAT fusion gene, we have been able to demonstrate that this promoter is active in ocelli.

Mismer, D.; Michael, W. M.; Laverty, T. R.; Rubin, G. M.

1988-01-01

141

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

142

Spectral Differentiation of Blue Opsins between Phylogenetically Close but Ecologically Distant Goldfish and Zebrafish  

Microsoft Academic Search

Zebrafish and goldfish are both diurnal freshwater fish species belonging to the same family, Cyprinidae, but their visual ecological surroundings considerably differ. Zebrafish are surface swimmers in conditions of broad and shortwave-dominated background spectra and goldfish are generalized swimmers whose light en- vironment extends to a depth of elevated short wave- length absorbance with turbidity. The peak absorption spectrum (max)

Akito Chinen; Yoshifumi Matsumoto; Shoji Kawamura

2005-01-01

143

Allelic Variation in Malawi Cichlid Opsins: A Tale of Two Genera  

Microsoft Academic Search

The role of sequence variation in the spectral tuning of color vision is well established in many systems. This includes the\\u000a cichlids of Lake Victoria where sequence variation has been linked to environmental light gradients and speciation. The cichlids\\u000a of Lake Malawi are a similar model for visual evolution, but the role of gene sequence variation in visual tuning between

Adam R. SmithKaren; Karen L. Carleton

2010-01-01

144

Opsin localization and chromophore retinoids identified within the basal brain of the lizard Anolis carolinensis  

Microsoft Academic Search

Since the beginning of this century evidence has accumulated which demonstrates that non-mammalian vertebrates possess photoreceptors situated deep within the brain. While many attempts have been made to localize these sensory cells, studies have either failed or been inconclusive. In this report we have used several experimental approaches to localize the deep brain photoreceptors of the lizard Anolis carolinensis. Using

R. G. Foster; J. M. Garcia-Fernandez; I. Provencio; W. J. DeGrip

1993-01-01

145

Evolution of the vertebrate eye: opsins, photoreceptors, retina and eye cup  

Microsoft Academic Search

Charles Darwin appreciated the conceptual difficulty in accepting that an organ as wonderful as the vertebrate eye could have evolved through natural selection. He reasoned that if appropriate gradations could be found that were useful to the animal and were inherited, then the apparent difficulty would be overcome. Here, we review a wide range of findings that capture glimpses of

Shaun P. Collin; Edward N. Pugh; Trevor D. Lamb

2007-01-01

146

Targeted knockdown of an opsin gene inhibits the swimming behaviour photoresponse of ascidian larvae  

Microsoft Academic Search

The sequencing of the ascidian Ciona intestinalis genome was completed at the end of 2002. Effective targeted gene knockdown in this model chordate would greatly enhance understanding of how the genes affect the function of the neurons that underlie behaviour. We show here that antisense morpholinos (MOs) are effective and specific translational inhibitors in C. intestinalis larvae. The larvae developed

Kyoko Inada; Takeo Horie; Takehiro Kusakabe; Motoyuki Tsuda

2003-01-01

147

Opsin gene duplication and diversification in the guppy, a model for sexual selection  

Microsoft Academic Search

Identification of genes that control variation in adaptive characters is a prerequisite for understanding the processes that drive sexual and natural selection. Male coloration and female colour perception play important roles in mate choice in the guppy (Poecilia reticulata), a model organism for studies of natural and sexual selection. We examined a potential source for the known variation in colour

Margarete Hoffmann; Namita Tripathi; Stefan R. Henz; Anna K. Lindholm; Detlef Weigel; Felix Breden; Christine Dreyer

2007-01-01

148

Evolution of the vertebrate eye: opsins, photoreceptors, retina and eye cup  

PubMed Central

Charles Darwin appreciated the conceptual difficulty in accepting that an organ as wonderful as the vertebrate eye could have evolved through natural selection. He reasoned that if appropriate gradations could be found that were useful to the animal and were inherited, then the apparent difficulty would be overcome. Here, we review a wide range of findings that capture glimpses of the gradations that appear to have occurred during eye evolution, and provide a scenario for the unseen steps that have led to the emergence of the vertebrate eye.

Lamb, Trevor D.; Collin, Shaun P.; Pugh, Edward N.

2011-01-01

149

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.

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

2006-01-01

150

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

151

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

152

MODELING LARGE WOOD STRUCTURES IN SAND BED STREAMS  

Technology Transfer Automated Retrieval System (TEKTRAN)

In-stream large wood structures (LWS) are becoming increasingly popular throughout the world. The LWS improve aquatic habitat quality and protect banks from erosion. While most reports describe the LWS in the Northwest as successful, LWS in one Mississippi sand-bed stream had an unacceptable failure...

153

Cell-Specific DNA Methylation Patterns of Retina-Specific Genes  

PubMed Central

Many studies have demonstrated that epigenetic mechanisms are important in the regulation of gene expression during embryogenesis, gametogenesis, and other forms of tissue-specific gene regulation. We sought to explore the possible role of epigenetics, specifically DNA methylation, in the establishment and maintenance of cell type-restricted gene expression in the retina. To assess the relationship between DNA methylation status and expression level of retinal genes, bisulfite sequence analysis of the 1000 bp region around the transcription start sites (TSS) of representative rod and cone photoreceptor-specific genes and gene expression analysis were performed in the WERI and Y79 human retinoblastoma cell lines. Next, the homologous genes in mouse were bisulfite sequenced in the retina and in non-expressing tissues. Finally, bisulfite sequencing was performed on isolated photoreceptor and non-photoreceptor retinal cells isolated by laser capture microdissection. Differential methylation of rhodopsin (RHO), retinal binding protein 3 (RBP3, IRBP) cone opsin, short-wave-sensitive (OPN1SW), cone opsin, middle-wave-sensitive (OPN1MW), and cone opsin, long-wave-sensitive (OPN1LW) was found in the retinoblastoma cell lines that inversely correlated with gene expression levels. Similarly, we found tissue-specific hypomethylation of the promoter region of Rho and Rbp3 in mouse retina as compared to non-expressing tissues, and also observed hypomethylation of retinal-expressed microRNAs. The Rho and Rbp3 promoter regions were unmethylated in expressing photoreceptor cells and methylated in non-expressing, non-photoreceptor cells from the inner nuclear layer. A third regional hypomethylation pattern of photoreceptor-specific genes was seen in a subpopulation of non-expressing photoreceptors (Rho in cones from the Nrl ?/? mouse and Opn1sw in rods). These results demonstrate that a number of photoreceptor-specific genes have cell-specific differential DNA methylation that correlates inversely with their expression level. Furthermore, these cell-specific patterns suggest that DNA methylation may play an important role in modulating photoreceptor gene expression in the developing mammalian retina.

Merbs, Shannath L.; Khan, Miriam A.; Hackler, Laszlo; Oliver, Verity F.; Wan, Jun; Qian, Jiang; Zack, Donald J.

2012-01-01

154

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

2013-05-30

155

Visual pigments in a living fossil, the Australian lungfish Neoceratodus forsteri  

PubMed Central

Background One of the greatest challenges facing the early land vertebrates was the need to effectively interpret a terrestrial environment. Interpretation was based on ocular adaptations evolved for an aquatic environment millions of years earlier. The Australian lungfish Neoceratodus forsteri is thought to be the closest living relative to the first terrestrial vertebrate, and yet nothing is known about the visual pigments present in lungfish or the early tetrapods. Results Here we identify and characterise five visual pigments (rh1, rh2, lws, sws1 and sws2) expressed in the retina of N. forsteri. Phylogenetic analysis of the molecular evolution of lungfish and other vertebrate visual pigment genes indicates a closer relationship between lungfish and amphibian pigments than to pigments in teleost fishes. However, the relationship between lungfish, the coelacanth and tetrapods could not be absolutely determined from opsin phylogeny, supporting an unresolved trichotomy between the three groups. Conclusion The presence of four cone pigments in Australian lungfish suggests that the earliest tetrapods would have had a colorful view of their terrestrial environment.

Bailes, Helena J; Davies, Wayne L; Trezise, Ann EO; Collin, Shaun P

2007-01-01

156

Advantage of dichromats over trichromats in discrimination of color-camouflaged stimuli in nonhuman primates.  

PubMed

Due to a middle- to long-wavelength-sensitive (M/LWS) cone opsin polymorphism, there is considerable phenotypic variation in the color vision of New World monkeys. Many females have trichromatic vision, whereas some females and all males have dichromatic vision. The selective pressures that maintain this polymorphism are unclear. In the present study we compared the performance of dichromats and trichromats in a discrimination task. We examined tri- and dichromatic individuals of two species: brown capuchin monkeys (Cebus apella) and long-tailed macaques (Macaca fascicularis). We also examined one protanomalous chimpanzee (Pan troglodytes). The subjects' task was to discriminate a circular pattern from other patterns in which textural elements differed in orientation and thickness from the background. After they were trained with stimuli of a single color, the subjects were presented with color-camouflaged stimuli with a green/red mosaic overlaid onto the pattern. The dichromatic monkeys and the protanomalous chimpanzee selected the correct stimulus under camouflaged conditions at rates significantly above chance levels, while the trichromats did not. These findings demonstrate that dichromatic nonhuman primates possess a superior visual ability to discriminate color-camouflaged stimuli, and that such an ability may confer selective advantages with respect to the detection of cryptic foods and/or predators. PMID:16342068

Saito, Atsuko; Mikami, Akichika; Kawamura, Shoji; Ueno, Yoshikazu; Hiramatsu, Chihiro; Widayati, Kanthi A; Suryobroto, Bambang; Teramoto, Migaku; Mori, Yusuke; Nagano, Kunitoshi; Fujita, Kazuo; Kuroshima, Hika; Hasegawa, Toshikazu

2005-12-01

157

The Living with a Star Data Environment  

Microsoft Academic Search

Living with a Star (LWS) is a program of applied scientific research geared towards understanding and predicting the effects of the Sun on human society. The LWS data environment is key to the success of the program. We will have to combine diverse data sets from a wide array of sources, including ones beyond the formal LWS missions. Data must

T. A. Kucera

2002-01-01

158

Effects of live weight at slaughter (6, 10 and 25 kg) on kid carcass and meat quality  

Microsoft Academic Search

In Mediterranean countries live weight at slaughter (LWS) for kid goats is lower than in Arabian or African countries. Logically, increasing LWS could increase a farmer’s profit margin. Forty-five twin male kids from the Canary Caprine Group breed were used to compare carcass and meat quality at 6, 10 and 25 kg LWS. Dressing percentage based on full weight was

A. Marichal; N. Castro; J. Capote; M. J. Zamorano; A. Argüello

2003-01-01

159

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.

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

2010-01-01

160

Evolutionary changes of multiple visual pigment genes in the complete genome of Pacific bluefin tuna  

PubMed Central

Tunas are migratory fishes in offshore habitats and top predators with unique features. Despite their ecological importance and high market values, the open-ocean lifestyle of tuna, in which effective sensing systems such as color vision are required for capture of prey, has been poorly understood. To elucidate the genetic and evolutionary basis of optic adaptation of tuna, we determined the genome sequence of the Pacific bluefin tuna (Thunnus orientalis), using next-generation sequencing technology. A total of 26,433 protein-coding genes were predicted from 16,802 assembled scaffolds. From these, we identified five common fish visual pigment genes: red-sensitive (middle/long-wavelength sensitive; M/LWS), UV-sensitive (short-wavelength sensitive 1; SWS1), blue-sensitive (SWS2), rhodopsin (RH1), and green-sensitive (RH2) opsin genes. Sequence comparison revealed that tuna's RH1 gene has an amino acid substitution that causes a short-wave shift in the absorption spectrum (i.e., blue shift). Pacific bluefin tuna has at least five RH2 paralogs, the most among studied fishes; four of the proteins encoded may be tuned to blue light at the amino acid level. Moreover, phylogenetic analysis suggested that gene conversions have occurred in each of the SWS2 and RH2 loci in a short period. Thus, Pacific bluefin tuna has undergone evolutionary changes in three genes (RH1, RH2, and SWS2), which may have contributed to detecting blue-green contrast and measuring the distance to prey in the blue-pelagic ocean. These findings provide basic information on behavioral traits of predatory fish and, thereby, could help to improve the technology to culture such fish in captivity for resource management.

Nakamura, Yoji; Mori, Kazuki; Saitoh, Kenji; Oshima, Kenshiro; Mekuchi, Miyuki; Sugaya, Takuma; Shigenobu, Yuya; Ojima, Nobuhiko; Muta, Shigeru; Fujiwara, Atushi; Yasuike, Motoshige; Oohara, Ichiro; Hirakawa, Hideki; Chowdhury, Vishwajit Sur; Kobayashi, Takanori; Nakajima, Kazuhiro; Sano, Motohiko; Wada, Tokio; Tashiro, Kosuke; Ikeo, Kazuho; Hattori, Masahira; Kuhara, Satoru; Gojobori, Takashi; Inouye, Kiyoshi

2013-01-01

161

A homozygous p.Glu150Lys mutation in the opsin gene of two Pakistani families with autosomal recessive retinitis pigmentosa  

PubMed Central

Purpose To identify the gene mutations responsible for autosomal recessive retinitis pigmentosa (arRP) in Pakistani families. Methods A cohort of consanguineous families with typical RP phenotype in patients was screened by homozygosity mapping using microsatellite markers that mapped close to 21 known arRP genes and five arRP loci. Mutation analysis was performed by direct sequencing of the candidate gene. Results In two families, RP21 and RP53, homozygosity mapping suggested RHO, the gene encoding rhodopsin, as a candidate disease gene on chromosome 3q21. In six out of seven affected members from the two families, direct sequencing of RHO identified a homozygous c.448G>A mutation resulting in the p.Glu150Lys amino acid change. This variant was first reported in PMK197, an Indian arRP family. Single nucleotide polymorphism analysis in RP21, RP53, and PMK197 showed a common disease-associated haplotype in the three families. Conclusions In two consanguineous Pakistani families with typical arRP phenotype in the patients, we identified a disease-causing mutation (p.Glu150Lys) in the RHO gene. Single nucleotide polymorphism analysis suggests that the previously reported Indian family (PMK197) and the two Pakistani families studied here share the RHO p.Glu150Lys mutation due to a common ancestry.

Azam, Maleeha; Khan, Muhammad Imran; Gal, Andreas; Hussain, Alamdar; Shah, Syed Tahir Abbas; Khan, Muhammad Shakil; Sadeque, Ahmed; Bokhari, Habib; Collin, Rob W.J.; Orth, Ulrike; van Genderen, Maria M.; den Hollander, A.I.; Cremers, Frans P. M.

2009-01-01

162

Identification and characterization of zebrafish ocular formation genes.  

PubMed

To study genes that are specifically expressed in the eyes, we employed microarray and in situ hybridization analyses to identify and characterize differentially expressed ocular genes in eyeless masterblind (mbl-/-) zebrafish (Danio rerio). Among 70 differentially expressed genes in the mbl-/- mutant identified by microarray analysis, 8 down-regulated genes were characterized, including 4 eye-specific genes, opsin 1 short-wave-sensitive 1 (opn1sw1), crystallinbetaa1b (cryba1b), crystallinbetaa2b (cryba2b), and crystallingamma M2d3 (crygm2d3); 2 eye and brain genes, ATPase, H+ transporting, lysosomal, V0 subunit c (atp6v0c) and basic leucine zipper and W2 domains 1a (bzw1a); and 2 constitutive genes, heat shock protein 8 (hspa8) and ribosomal protein L7a (rpl7a). In situ hybridization experiments confirmed down-regulation of these 8 ocular formation genes in mbl-/- zebrafish and showed their ocular and dynamic temporal expression patterns during zebrafish early development. Further, an automated literature analysis of the 70 differentially expressed genes identified a sub-network of genes with known associations, either with each other or with ocular structures or development, and shows how this study contributes to the current body of knowledge. PMID:18356958

Wang, Han; Kesinger, Jason W; Zhou, Qingchun; Wren, Jonathan D; Martin, George; Turner, Sean; Tang, Yuhong; Frank, Mark Barton; Centola, Michael

2008-03-01

163

The Living With A Star Program  

Microsoft Academic Search

The goal of NASA's Living With a Star (LWS) program is to develop the scientific understanding necessary to address effectively those aspects of the connected Sun-Earth system that affect life and society. LWS has solar, heliospheric, magnetospheric and ionospheric elements, and efforts are underway to forge a connection with the atmospheric and Earth science community. An understanding of the Sun's

O. C. St. Cyr; B. Giles; A. Poland; L. Zanetti; B. Mauk

2003-01-01

164

Mechanical Characteristics of Light-Weighted Soils Using Dredged Materials  

Microsoft Academic Search

This study investigates the mechanical characteristics of light-weighted soils (LWS) consisting of expanded polystyrene (EPS), dredged clays, and cement through both unconfined and triaxial compression tests. The mechanical characteristics of the compressive strength of LWS are analyzed with varying initial water contents of dredged clays, EPS ratio, cement ratio, and curing pressure. In the triaxial compression test, it is found

Gil-Lim Yoonz; Sang-Soo Jeon; Byung-Tak Kim

2004-01-01

165

Stress-Strain Behavior of Light-Weighted Soils  

Microsoft Academic Search

Unconfined and triaxial compression tests were carried out to examine the behavior of light-weighted soils (LWS) consisting of expanded polystyrene (EPS), dredged soils, and cement with respect to initial water content. The stress-strain behavior of LWS are analyzed with varying initial water content and silt contents of dredged soils, cement ratio, and confined stress. As initial water contents increase, the

Gil-Lim Yoon; Byung-Tak Kim; Sang-Soo Jeon

2011-01-01

166

Infrared rubidium atomic resonant filters for low wavenumber scattering  

Microsoft Academic Search

This dissertation presents new approaches for low wavenumber scattering (LWS) based on infra-red rubidium filters, including blocking filters, dispersion filters, and passband filters. LWS is scattering of light with a small frequency change, such as rotational Raman scattering and Thomson scattering, which enables the measurement of species specific properties. The rubidium filters are used in conjunction with a tunable, pulsed

Zhen Tang

2001-01-01

167

Targeted Research and Technology Within NASA's Living With a Star Program.  

National Technical Information Service (NTIS)

NASA's Living With a Star (LWS) initiative is a systematic, goal-oriented research program targeting those aspects of the Sun-Earth system that affect society. The Targeted Research and Technology (TR&T) component of LWS provides the theory, modeling,...

M. Hesse

2003-01-01

168

A systematic literature review of psychological factors and the development of late whiplash syndrome  

Microsoft Academic Search

This systematic literature review aims to assess the prognostic value of psychological factors in the development of late whiplash syndrome (LWS). We included prospective cohort studies that provided a baseline measure of at least one psychological variable and used outcome measures relating to LWS (i.e. pain or disability persisting 6 months post injury). A search of electronic databases (Pubmed, Medline,

Esther Williamson; Mark Williams; Simon Gates; Sarah E. Lamb

2008-01-01

169

Spatiotemporal coordination of rod and cone photoreceptor differentiation in goldfish retina.  

PubMed

In this study, we have compared spatial and temporal aspects of development of new rods and cones in the adult goldfish by using a combination of bromodeoxyuridine immunocytochemistry and opsin in situ hybridization to determine the intervals between terminal mitosis (cell "birth") and expression of opsin mRNA for each photoreceptor cell type. The goldfish opsins include rod opsin and four different cone opsins: red, green, blue, and ultraviolet. In a cohort of photoreceptors born at the same time, rods expressed opsin mRNA within 3 days of cell birth, while expression of cone opsin mRNA required at least 7 days. This temporal discrepancy in differentiation, coupled with a discordance in the site of cell genesis of rods and cones, allowed opsin expression to commence in both cell types in approximately the same retinal location. Commitment to the generic cone phenotype occurred within approximately 6 days throughout the cone cohort, as indicated by expression of interphotoreceptor retinoid-binding protein (IRBP) mRNA, but expression of a specific spectral phenotype was delayed until rods differentiated nearby. Onset of expression of cone opsin mRNA followed a phenotype-specific sequence: red, then green, then blue, and finally ultraviolet; in situ hybridization with two opsin probes confirmed that individual photoreceptors expressed only one type of opsin as they differentiated. This stepwise process of cone differentiation is consistent with the hypothesis that cell-cell interactions among developing photoreceptors may coordinate selection of specific photoreceptor phenotypes. PMID:9183694

Stenkamp, D L; Barthel, L K; Raymond, P A

1997-06-01

170

Using 2-D arrays for sensing multimodal Lamb waves  

NASA Astrophysics Data System (ADS)

Monitoring structural integrity of large planar structures requires normally a relatively dense network of uniformly distributed ultrasonic sensors. A 2-D ultrasonic phased array with all azimuth angle coverage would be extremely useful for the structural health monitoring (SHM) of such structures. Known techniques for estimating direction of arriving (DOA) waves cannot efficiently cope with dispersive and multimodal Lamb waves (LWs). In the paper we propose an adaptive spectral estimation technique capable of handling broadband LWs sensed by 2-D arrays, the modified Capon method. Performance of the technique is evaluated using simulated multiple-mode LWs, and verified using experimental data.

Engholm, Marcus; Stepinski, Tadeusz

2010-03-01

171

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

172

The nop-1 gene of Neurospora crassa encodes a seven transmembrane helix retinal-binding protein homologous to archaeal rhodopsins  

PubMed Central

Opsins are a class of retinal-binding, seven transmembrane helix proteins that function as light-responsive ion pumps or sensory receptors. Previously, genes encoding opsins had been identified in animals and the Archaea but not in fungi or other eukaryotic microorganisms. Here, we report the identification and mutational analysis of an opsin gene, nop-1, from the eukaryotic filamentous fungus Neurospora crassa. The nop-1 amino acid sequence predicts a protein that shares up to 81.8% amino acid identity with archaeal opsins in the 22 retinal binding pocket residues, including the conserved lysine residue that forms a Schiff base linkage with retinal. Evolutionary analysis revealed relatedness not only between NOP-1 and archaeal opsins but also between NOP-1 and several fungal opsin-related proteins that lack the Schiff base lysine residue. The results provide evidence for a eukaryotic opsin family homologous to the archaeal opsins, providing a plausible link between archaeal and visual opsins. Extensive analysis of ?nop-1 strains did not reveal obvious defects in light-regulated processes under normal laboratory conditions. However, results from Northern analysis support light and conidiation-based regulation of nop-1 gene expression, and NOP-1 protein heterologously expressed in Pichia pastoris is labeled by using all-trans [3H]retinal, suggesting that NOP-1 functions as a rhodopsin in N. crassa photobiology.

Bieszke, Jennifer A.; Braun, Edward L.; Bean, Laura E.; Kang, Seogchan; Natvig, Donald O.; Borkovich, Katherine A.

1999-01-01

173

Living with a Star Program Mission Plan.  

National Technical Information Service (NTIS)

LWS (Living With a Star) is research science focused to facilitate enabling science for spacecraft design (specifically environment specification models) and spacecraft operations (specifically Space Weather research). The following topics are discussed: ...

J. Barth

2001-01-01

174

Distinct Evolutionary Patterns Between Two Duplicated Color Vision Genes Within Cyprinid Fishes  

Microsoft Academic Search

We investigated the molecular evolution of duplicated color vision genes (LWS-1 and SWS2) within cyprinid fish, focusing on the most cavefish-rich genus—Sinocyclocheilus. Maximum likelihood-based codon substitution approaches were used to analyze the evolution of vision genes. We found that\\u000a the duplicated color vision genes had unequal evolutionary rates, which may lead to a related function divergence. Divergence\\u000a of LWS-1 was

Zhiqiang Li; Xiaoni Gan; Shunping He

2009-01-01

175

Prickly pear nopals pectin from Opuntia ficus-indica physico-chemical study in dilute and semi-dilute solutions  

Microsoft Academic Search

The water soluble fraction of peeled prickly pear nopals called native sample (NS) has been characterised mainly by SEC\\/MALLS analysis. Two main components have been identified: one with high average molar mass (Mw of 13×106gmol?1) called the high weight sample (HWS), the other being a low Mw fraction (LWS). After extensive ultra filtration of NS, isolated HWS and LWS are

H Majdoub; S Roudesli; L Picton; D Le Cerf; G Muller; M Grisel

2001-01-01

176

Photochemistry of a putative new class of sensory rhodopsin (SRIII) coded by xop2 of Haloarcular marismortui  

Microsoft Academic Search

Baliga et al. (2004) [1] reported the existence of a functionally unpredictable opsin gene, named xop2, in Haloarcula marismortui, a holophilic archaeon. Ihara et al. [38] performed molecular phylogenetic analysis and determined that the product of xop2 belonged to a new class of opsins in the sensory rhodopsins. This microbial rhodopsin was therefore named H. marismortui sensory rhodopsin III (HmSRIII).

Yutaka Nakao; Takashi Kikukawa; Kazumi Shimono; Jun Tamogami; Noriko Kimitsuki; Toshifumi Nara; Masashi Unno; Kunio Ihara; Naoki Kamo

2011-01-01

177

Derivation of human differential photoreceptor-like cells from the iris by defined combinations of CRX, RX and NEUROD.  

PubMed

Examples of direct differentiation by defined transcription factors have been provided for beta-cells, cardiomyocytes and neurons. In the human visual system, there are four kinds of photoreceptors in the retina. Neural retina and iris-pigmented epithelium (IPE) share a common developmental origin, leading us to test whether human iris cells could differentiate to retinal neurons. We here define the transcription factor combinations that can determine human photoreceptor cell fate. Expression of rhodopsin, blue opsin and green/red opsin in induced photoreceptor cells were dependent on combinations of transcription factors: A combination of CRX and NEUROD induced rhodopsin and blue opsin, but did not induce green opsin; a combination of CRX and RX induced blue opsin and green/red opsin, but did not induce rhodopsin. Phototransduction-related genes as well as opsin genes were up-regulated in those cells. Functional analysis; i.e. patch clamp recordings, clearly revealed that generated photoreceptor cells, induced by CRX, RX and NEUROD, responded to light. The response was an inward current instead of the typical outward current. These data suggest that photosensitive photoreceptor cells can be generated by combinations of transcription factors. The combination of CRX and RX generate immature photoreceptors: and additional NEUROD promotes maturation. These findings contribute substantially to a major advance toward eventual cell-based therapy for retinal degenerative diseases. PMID:22558175

Seko, Yuko; Azuma, Noriyuki; Kaneda, Makoto; Nakatani, Kei; Miyagawa, Yoshitaka; Noshiro, Yuuki; Kurokawa, Reiko; Okano, Hideyuki; Umezawa, Akihiro

2012-04-25

178

Morphological, physiological, and biochemical changes in rhodopsin knockout mice  

PubMed Central

Mutations in rod opsin, the visual pigment protein of rod photoreceptors, account for ?15% of all inherited human retinal degenerations. However, the physiological and molecular events underlying the disease process are not well understood. One approach to this question has been to study transgenic mice expressing opsin genes containing defined mutations. A caveat of this approach is that even the overexpression of normal opsin leads to photoreceptor cell degeneration. To overcome the problem, we have reduced or eliminated endogenous rod opsin content by targeted gene disruption. Retinas in mice lacking both opsin alleles initially developed normally, except that rod outer segments failed to form. Within months of birth, photoreceptor cells degenerated completely. Retinas from mice with a single copy of the opsin gene developed normally, and rods elaborated outer segments of normal size but with half the normal complement of rhodopsin. Photoreceptor cells in these retinas also degenerated but did so over a much slower time course. Physiological and biochemical experiments showed that rods from mice with a single opsin gene were ?50% less sensitive to light, had accelerated flash-response kinetics, and contained ?50% more phosducin than wild-type controls.

Lem, J.; Krasnoperova, N. V.; Calvert, P. D.; Kosaras, B.; Cameron, D. A.; Nicolo, M.; Makino, C. L.; Sidman, R. L.

1999-01-01

179

Chlamyrhodopsin represents a new type of sensory photoreceptor.  

PubMed

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. PMID:8846778

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

1995-12-01

180

Modulation of propagation-invariant Localized Waves for FSO communication systems.  

PubMed

The novel concept of spatio-temporal modulation of Nyquist pulses is introduced, and the resulting wave-packets are termed Nyquist Localized Waves (LWs). Ideal Nyquist LWs belong to the generic family of LW solutions and can propagate indefinitely in unbounded media without attenuation or chromatic dispersion. The possibility of modulating Nyquist LWs for free-space optical (FSO) communication systems is demonstrated using two different modulation techniques. The first technique is on-off keying (OOK) with alternate mark inversion (AMI) coding for 1-bit per symbol transmission, and the second one is 16-ary quadrature amplitude modulation (16-QAM) for 4-bits per symbol transmission. Aspects related to the performance, detection and generation of the spatio-temporally coupled wave-packets are discussed and future research directions are outlined. PMID:22772211

Salem, Mohamed A; Ba?c?, Hakan

2012-07-01

181

Performance testing of doped-germanium photoconductors for the ISO long wavelength spectrometer  

NASA Astrophysics Data System (ADS)

The ISO (Infrared Space Observatory) Long Wavelength Spectrometer (LWS) uses an array of ten doped germanium photoconductors to cover the wavelength range 45 to 200 micrometers. The performance of the detectors was characterized, optimized, and calibrated, both individually and in the flight instrument. The detector test techniques and calibration methods are described and results for the spectral response, dark current, responsivity, and noise equivalent power are presented. The dependence of these parameters on operating conditions was explored and optimum values established for the flight instrument. Calibration of the flight instrument demonstrated that the sensitivity of the LWS is within specifications.

Church, S. E.; Griffin, M. J.; Ade, P. A. R.; Price, M. C.; Emery, R. J.; Swinyard, B. M.

1992-12-01

182

Single-Copy Nuclear Genes Recover Cretaceous-Age Divergences in Bees  

Microsoft Academic Search

We analyzed the higher level phylogeny of the bee family Halictidae based on the coding regions of three single-copy nuclear genes (long-wavelength (LW) opsin, wingless, and elongation factor 1-? (EF-1?)). Our combined data set consisted of 2,234 aligned nucleotide sites (702 base pairs (bp) for LW opsin, 405 bp for wingless, and 1,127 bp for EF-1?) and 779 parsimony-informative sites.

BRYAN N. DANFORTH; S E ´ AN G. BRADY; SEDONIA SIPES; ADAM PEARSON

2004-01-01

183

Spectral heterogeneity of honeybee ommatidia  

Microsoft Academic Search

The honeybee compound eye is equipped with ultraviolet, blue, and green receptors, which form the physiological basis of a\\u000a trichromatic color vision system. We studied the distribution of the spectral receptors by localizing the three mRNAs encoding\\u000a the opsins of the ultraviolet-, blue- and green-absorbing visual pigments. The expression patterns of the three opsin mRNAs\\u000a demonstrated that three distinct types

Motohiro Wakakuwa; Masumi Kurasawa; Martin Giurfa; Kentaro Arikawa

2005-01-01

184

The pineal organ is the first differentiated light receptor in the embryonic salmon, Salmo salar L  

Microsoft Academic Search

The initial appearance of S-antigen, a-transducin, opsin and 5-HT during embryogenesis of the pineal organ and retina was studied by means of immunocytochemistry in the Atlantic salmon, Salmo salar L. The presence of these substances may be taken as a good indication of photoreceptor differentiation; a-transducin and S-antigen are involved in the phototransduction process, opsin is the proteinaceous component of

Thomas Östholm; Eva Brännäs; Theo Veen

1987-01-01

185

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

PubMed

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 A(1) 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 A(2) absorbance spectra corrected for skin/skull absorbance indicates that the A(2) 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

2012-08-15

186

Chromatic coding from cone-type unselective circuits in the mouse retina.  

PubMed

Retinal specializations such as cone-photoreceptor opsin-expression gradients, as found in several vertebrate species, are intuitively considered detrimental to color vision. In mice, the majority of cones coexpress both "blue" and "green" opsin. The coexpression ratio changes along the dorsoventral axis, resulting in a "green"-dominant dorsal and a "blue"-dominant ventral retina. Here, we asked how these specializations affect chromatic processing, especially with respect to the opsin transitional zone, the band where opsin coexpression shifts from "green" to "blue." Using electrophysiology, modeling, and calcium imaging, we found that "alpha-like" retinal ganglion cells, which previously have not been implicated in chromatic processing, display color-opponent responses when located in the vicinity of the opsin transitional zone. Moreover, direction-selective ganglion cells within this zone respond differentially to color sequences. Our data suggest that the dorsoventral opsin distribution, in combination with conventional spatiotemporal processing, renders mouse ganglion cell responses color-opponent without requiring cone-type selective connectivity. PMID:23395380

Chang, Le; Breuninger, Tobias; Euler, Thomas

2013-02-01

187

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.

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

2012-01-01

188

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

189

CO emission from shock and PDR in C-rich PN and post-AGB objects  

Microsoft Academic Search

The LWS full grating scans of the PN, NGC 7027, and post-AGB objects, GL618 and GL2688 reveal a forest of lines which are identified as CO rotational lines. These lines are used as diagnostics for warm gas around these objects. For NGC 7027 and GL 618, the hot central star is the source of the ionizing photons, creating a PDR.

K. Justtanont; M. J. Barlow; X. W. Liu; A. G. G. M. Tielens; R. J. Sylvester; P. Cox; N. Q. Rieu; C. J. Skinner

1999-01-01

190

Instrumentation at the Keck Observatory  

Microsoft Academic Search

The twin 10-m telescopes of the W.M. Keck Observatory have now been in operation for almost a decade. The original complement of first generation instruments remains in use (NIRC, HIRES, LRIS, and LWS) and all second generation instruments have been commissioned and are in regular operation (NIRSPEC, ESI, NIRC2 and DEIMOS). Both telescopes are equipped with Adaptive Optics (AO) systems,

Ian S. McLean; Sean Adkins

2004-01-01

191

Expression Profiles of Somatotropic Axis Genes in Lines of Chickens Divergently Selected for 56Day Body Weight  

Microsoft Academic Search

The objective of this study was to evaluate mRNA expression of somatotropic axis genes in chickens divergently selected for high (HWS) or low (LWS) body weight at 56 days of age. Gene expression was measured on days 16, 18, and 20 of incubation, day of hatch, and days 3, 7, 28, and 56 posthatch. Pituitary growth hormone mRNA raised from

Guiqin Wu; Paul B. Siegel; Elizabeth R. Gilbert; Ning Yang; Eric A. Wong

2011-01-01

192

AICAR and Compound C regulate food intake independently of AMP-activated protein kinase in lines of chickens selected for high or low body weight  

Microsoft Academic Search

AMP-activated protein kinase (AMPK) functions to maintain cellular and body energy balance. Our aim was to investigate the effect of intracerebroventricular (ICV) administration of AMPK stimulator AICAR and AMPK inhibitor Compound C on food intake in lines of chickens that had undergone long-term selection from a common founder population for high (HWS) or low (LWS) body weight. AICAR caused a

Pingwen Xu; Paul B. Siegel; D. Michael Denbow

2011-01-01

193

FIELD EVALUJATION OF LOW-EMISSION COAL BURNER TECHNOLOGY ON UTILITY BOILERS; VOLUME V. BURNER EVALUATION DATA APPENDICES  

EPA Science Inventory

The report gives a detailed summary of data which were generated during the testing of experimental burners on EPA's Large Watertube Simulator (LWS) test facility. The test data are presented as a series of appendices. Appendix A describe the data quality assurance procedures whi...

194

FIELD EVALUATION OF LOW-EMISSION COAL BURNER TECHNOLOGY ON UTILITY BURNERS VOLUME V. BURNER EVALUATION DATA APPENDICES  

EPA Science Inventory

The report gives a detailed summary of data which were generated during the testing of experimental burners on EPA's Large Watertube Simulator (LWS) test facility. The test data are presented as a series of appendices. Appendix A describe the data quality assurance procedures whi...

195

Performance testing of doped-germanium photoconductors for the ISO long wavelength spectrometer  

Microsoft Academic Search

The ISO (Infrared Space Observatory) Long Wavelength Spectrometer (LWS) uses an array of ten doped germanium photoconductors to cover the wavelength range 45 to 200 micrometers. The performance of the detectors was characterized, optimized, and calibrated, both individually and in the flight instrument. The detector test techniques and calibration methods are described and results for the spectral response, dark current,

S. E. Church; M. J. Griffin; P. A. R. Ade; M. C. Price; R. J. Emery; B. M. Swinyard

1992-01-01

196

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...

197

Effects of Taper Length on Traffic Operations in Construction Zones.  

National Technical Information Service (NTIS)

The study dealt with a proposed taper length formula that yields shorter tapers at design speeds below 60 mph than the existing formula, L=WS. Speed, erratic maneuvers, conflicts and encroachment data were collected at four sites, day and night, covering ...

J. L. Graham M. C. Sharp

1977-01-01

198

Global-scale Observations of the Limb and Disk (GOLD): Science Objectives  

Microsoft Academic Search

Developing the scientific understanding necessary to address aspects of the connected Sun-Earth system that directly affect life and society is a challenge for the scientific community in general and the Living With a Star (LWS) program in particular. Far Ultraviolet (FUV) observations from satellites have made vital contributions to this understanding. The Global-scale Observations of the Earth and Disk (GOLD)

R. Eastes; W. McClintock; A. Aksnes; D. Anderson; L. Andersson; A. Burns; M. Codrescu; R. Daniell; F. Eparvier; J. Harvey; A. Krywonos; J. Lumpe; G. Prölss; A. Richmond; D. Rusch; S. Solomon; D. Strickland; T. Woods

2006-01-01

199

Radwaste volume in lithium and Flibe thick liquid wall and comparison to conventional SW concepts  

Microsoft Academic Search

Among the advantages offered by the deployment of thick liquid walls (LW) in high power density reactors is the substantial reduction in radwaste volume and hazard that is mainly attributed to the extended lifetime of structural materials. In this paper, we quantitatively estimate the volume of the generated waste when different thick LWs are used. In particular, we make a

M. Z Youssef; M. E Sawan

2002-01-01

200

A cluster randomized trial to evaluate a health education programme "Living with Sun at School".  

PubMed

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

2012-07-02

201

How surrounds affect chromaticity discrimination.  

PubMed

Chromatic discrimination thresholds were measured with and without surrounds along two cardinal axes of chromaticity space. On one axis the level of short-wavelength-sensitive (SWS)-cone excitation was varied for constant long-wavelength-sensitive (LWS)-cone and medium-wavelength-sensitive (MWS)-cone excitations, and on the other axis there were equal and opposite changes in LWS-cone and MWS-cone excitations for constant levels of SWS-cone excitation. Results for two of three observers showed that with a dark surround, discrimination mediated by SWS cones was regulated by the level of SWS-cone excitation of the starting chromaticity, showing a function with the form of a threshold-versus-radiance function. For an equiluminant white or yellow surround, the discrimination for all three observers showed a minimum at the level of SWS-cone excitation of the surround, giving a V-shaped function for the white surround. An additional experiment with dimmer white surrounds indicated that while the minimum remained at the white point, the function gradually changed toward the shape with a dark surround. Discrimination thresholds mediated by LWS and MWS cones with a dark surround showed a minimum near the LWS-cone excitation of equal-energy white, giving a V-shaped function. The effect of yellow and white surrounds was to deepen the V. The data can be described by a model of chromatic discrimination incorporating a threshold term, a cone gain control, and an opponent gain control into two equations, one for SWS-cone discrimination and one for LWS-cone and MWS-cone discrimination. PMID:8459293

Miyahara, E; Smith, V C; Pokorny, J

1993-04-01

202

The evolution of complexity in the visual systems of stomatopods: insights from transcriptomics.  

PubMed

Stomatopod crustaceans have complex visual systems containing up to 16 different spectral classes of photoreceptors, more than described for any other animal. A previous molecular study of this visual system focusing on the expression of opsin genes found many more transcripts than predicted on the basis of physiology, but was unable to fully document the expressed opsin genes responsible for this diversity. Furthermore, questions remain about how other components of phototransduction cascades are involved. This study continues prior investigations by examining the molecular function of stomatopods' visual systems using new whole eye 454 transcriptome datasets from two species, Hemisquilla californiensis and Pseudosquilla ciliata. These two species represent taxonomic diversity within the order Stomatopoda, as well as variations in the anatomy and physiology of the visual system. Using an evolutionary placement algorithm to annotate the transcriptome, we identified the presence of nine components of the stomatopods' G-protein-coupled receptor (GPCR) phototransduction cascade, including two visual arrestins, subunits of the heterotrimeric G-protein, phospholipase C, transient receptor potential channels, and opsin transcripts. The set of expressed transduction genes suggests that stomatopods utilize a Gq-mediated GPCR-signaling cascade. The most notable difference in expression between the phototransduction cascades of the two species was the number of opsin contigs recovered, with 18 contigs found in retinas of H. californiensis, and 49 contigs in those of P. ciliata. Based on phylogenetic placement and fragment overlap, these contigs were estimated to represent 14 and 33 expressed transcripts, respectively. These data expand the known opsin diversity in stomatopods to clades of arthropod opsins that are sensitive to short wavelengths and ultraviolet wavelengths and confirm the results of previous studies recovering more opsin transcripts than spectrally distinct types of photoreceptors. Many of the recovered transcripts were phylogenetically placed in an evolutionary clade of crustacean opsin sequences that is rapidly expanding as the visual systems from more species are investigated. We discuss these results in relation to the emerging pattern, particularly in crustacean visual systems, of the expression of multiple opsin transcripts in photoreceptors of the same spectral class, and even in single photoreceptor cells. PMID:23727979

Porter, Megan L; Speiser, Daniel I; Zaharoff, Alexander K; Caldwell, Roy L; Cronin, Thomas W; Oakley, Todd H

2013-05-31

203

The Eyes Have It: Regulatory and Structural Changes Both Underlie Cichlid Visual Pigment Diversity  

PubMed Central

A major goal of evolutionary biology is to unravel the molecular genetic mechanisms that underlie functional diversification and adaptation. We investigated how changes in gene regulation and coding sequence contribute to sensory diversification in two replicate radiations of cichlid fishes. In the clear waters of Lake Malawi, differential opsin expression generates diverse visual systems, with sensitivities extending from the ultraviolet to the red regions of the spectrum. These sensitivities fall into three distinct clusters and are correlated with foraging habits. In the turbid waters of Lake Victoria, visual sensitivity is constrained to longer wavelengths, and opsin expression is correlated with ambient light. In addition to regulatory changes, we found that the opsins coding for the shortest- and longest-wavelength visual pigments have elevated numbers of potentially functional substitutions. Thus, we present a model of sensory evolution in which both molecular genetic mechanisms work in concert. Changes in gene expression generate large shifts in visual pigment sensitivity across the collective opsin spectral range, but changes in coding sequence appear to fine-tune visual pigment sensitivity at the short- and long-wavelength ends of this range, where differential opsin expression can no longer extend visual pigment sensitivity.

Marshall, N. Justin; Cronin, Thomas W.; Seehausen, Ole; Carleton, Karen L.

2009-01-01

204

Coexpression of three middle wavelength-absorbing visual pigments in sexually dimorphic photoreceptors of the butterfly Colias erate.  

PubMed

The tiered ommatidia of the Eastern Pale Clouded yellow butterfly, Colias erate, contain nine photoreceptor cells, four of which contribute their rhabdomeral microvilli to the distal tier of the rhabdom. We analyzed the visual pigments and spectral sensitivities of these distal photoreceptors in both sexes of Colias erate. A subset of photoreceptor cells expresses a newly discovered middle wavelength-absorbing opsin, Colias erate Blue (CeB), in addition to two previously described middle wavelength-absorbing opsins, CeV1 and CeV2. The other photoreceptors either coexpress CeV1 and CeV2, or exclusively express a short wavelength-absorbing opsin, CeUV, or a long wavelength-absorbing opsin, CeL. Males and females have the same visual pigment expression patterns, but the photoreceptor spectral sensitivities are sexually dimorphic. The photoreceptors coexpressing three middle wavelength-absorbing opsins are broad-blue receptors in males, but in females they are narrow-blue receptors. Those with CeV1 and CeV2 are violet receptors in females, while they are shouldered-blue receptors in males. The sexual dimorphism in spectral sensitivity is caused by a sex-specific distribution of fluorescent pigment that functions as a spectral filter. PMID:22972231

Ogawa, Yuri; Awata, Hiroko; Wakakuwa, Motohiro; Kinoshita, Michiyo; Stavenga, Doekele G; Arikawa, Kentaro

2012-09-13

205

Molecular physiology of rhodopsin: Computer simulation  

NASA Astrophysics Data System (ADS)

Computer simulation is used for comparative investigation of the molecular dynamics of rhodopsin containing the chromophore group (11- cis-retinal) and free opsin. Molecular dynamics is traced within a time interval of 3000 ps; 3 × 106 discrete conformational states of rhodopsin and opsin are obtained and analyzed. It is demonstrated that the presence of the chromophore group in the chromophore center of opsin influences considerably the nearest protein environment of 11- cis-retinal both in the region of the ?-ionone ring and in the region of the protonated Schiff base bond. Based on simulation results, a possible intramolecular mechanism of keeping rhodopsin as a G-protein-coupled receptor in the inactive state, i.e., the chromophore function as an efficient ligand antagonist, is discussed.

Fel'Dman, T. B.; Kholmurodov, Kh. T.; Ostrovsky, M. A.

2008-03-01

206

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.

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

2011-01-01

207

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

PubMed

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

2010-12-15

208

Engineering of an Artificial Light-Modulated Potassium Channel  

PubMed Central

Ion Channel-Coupled Receptors (ICCRs) are artificial receptor-channel fusion proteins designed to couple ligand binding to channel gating. We previously validated the ICCR concept with various G protein-coupled receptors (GPCRs) fused with the inward rectifying potassium channel Kir6.2. Here we characterize a novel ICCR, consisting of the light activated GPCR, opsin/rhodopsin, fused with Kir6.2. To validate our two-electrode voltage clamp (TEVC) assay for activation of the GPCR, we first co-expressed the apoprotein opsin and the G protein-activated potassium channel Kir3.1F137S (Kir3.1*) in Xenopus oocytes. Opsin can be converted to rhodopsin by incubation with 11-cis retinal and activated by light-induced retinal cis?trans isomerization. Alternatively opsin can be activated by incubation of oocytes with all-trans-retinal. We found that illumination of 11-cis-retinal-incubated oocytes co-expressing opsin and Kir3.1* caused an immediate and long-lasting channel opening. In the absence of 11-cis retinal, all-trans-retinal also opened the channel persistently, although with slower kinetics. We then used the oocyte/TEVC system to test fusion proteins between opsin/rhodopsin and Kir6.2. We demonstrate that a construct with a C-terminally truncated rhodopsin responds to light stimulus independent of G protein. By extending the concept of ICCRs to the light-activatable GPCR rhodopsin we broaden the potential applications of this set of tools.

Caro, Lydia N.; Moreau, Christophe J.; Estrada-Mondragon, Argel; Ernst, Oliver P.; Vivaudou, Michel

2012-01-01

209

In Vivo Application of Optogenetics for Neural Circuit Analysis  

PubMed Central

Optogenetics combines optical and genetic methods to rapidly and reversibly control neural activities or other cellular functions. Using genetic methods, specific cells or anatomical pathways can be sensitized to light through exogenous expression of microbial light activated opsin proteins. Using optical methods, opsin expressing cells can be rapidly and reversibly controlled by pulses of light of specific wavelength. With the high spatial temporal precision, optogenetic tools have enabled new ways to probe the causal role of specific cells in neural computation and behavior. Here, we overview the current state of the technology, and provide a brief introduction to the practical considerations in applying optogenetics in vivo to analyze neural circuit functions.

2012-01-01

210

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 personÃÂs 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

211

Complete ISOPHOT (C200) Maps of a Nearby Prototypical GMC: W3 (Spring) or NGC7538 (Fall)  

NASA Astrophysics Data System (ADS)

We were originally awarded Priority 3 time (approximately 60,000 sec) with Infrared Space Observatory (ISO) to obtain a complete ISOPHOT (PHT32-C200) map of a nearby prototypical giant molecular cloud (GMC). Following the FALL launch and revised estimates for the sensitivity of the ISOPHOT detectors, our program was modified to fit within the time constraints while still carrying out the main science requirements. The revised program requested long strip maps of our FALL target (NGC7538) using sequences of PHT37/38/39 observations with LWS observations of the brightest regions. The large number of AOTs required to cover each GMC required that our observations be spread over four separate proposals (PROP-01, PROP-02, PROP-03, PROP-04) which together comprise a single observing program. Our program was executed in early 1997; nearly 50,000 sec of data were obtained, including all of our requested ISOPHOT C200 observations. None of the LWS data were taken.

Sanders, David B.

2001-01-01

212

Atmospheric correction for NO2 absorption in retrieving water-leaving reflectances from the SeaWiFS and MODIS measurements.  

PubMed

The absorption by atmospheric nitrogen dioxide (NO2) gas in the visible has been traditionally neglected in the retrieval of oceanic parameters from satellite measurements. Recent measurements of NO2 from spaceborne sensors show that over the Eastern United States the NO2 column amount often exceeds 1 Dobson Unit (approximately 2.69x10(16) molecules/cm2). Our radiative transfer sensitivity calculations show that under high NO2 conditions (approximately 1x10(16) molecules/cm2) the error in top-of-atmosphere (TOA) reflectance in the blue channels of the sea-viewing wide field-of-view sensor (SeaWiFS) and moderate-resolution imaging spectroradiometer (MODIS) sensors is approximately 1%. This translates into approximately 10% error in water-leaving radiance for clear waters and to higher values (>20%) in the coastal areas. We have developed an atmospheric-correction algorithm that allows an accurate retrieval of normalized water-leaving radiances (nLws) in the presence of NO2 in the atmosphere. The application of the algorithm to 52 MODIS scenes over the Chesapeake Bay area show a decrease in the frequency of negative nLw estimates in the 412 nm band and an increase in the value of nLws in the same band. For the particular scene reported in this paper, the mean value of nLws in the 412 nm band increased by 17%, which is significant, because for the MODIS sensor the error in nLws attributable to the digitization error in the observed TOA reflectance over case 2 waters is approximately 2.5%. PMID:17846643

Ahmad, Ziauddin; McClain, Charles R; Herman, Jay R; Franz, Bryan A; Kwiatkowska, Ewa J; Robinson, Wayne D; Bucsela, Eric J; Tzortziou, Maria

2007-09-10

213

Both concreteness and age-of-acquisition affect reading accuracy but only concreteness affects comprehension in a deep dyslexic patient  

Microsoft Academic Search

As concreteness correlates very highly with the age-of-acquisition (AoA) of words, we attempted to disentangle the effects of these two variables in the oral reading and comprehension performance of the deep dyslexic patient LW. The results of a multiple regression analysis of LW’s reading of 217 words showed that both AoA and concreteness affect reading accuracy, with the AoA effect

Christopher Barry; Simon Gerhand

2003-01-01

214

Wachstumslenkende operative Behandlung der juvenilen Skoliose mit USS paediatric  

Microsoft Academic Search

Zusammenfassung\\u000a Operationsziel  Mit dem USS-paediatric-Instrumentarium können bei jugendlichen Patienten, bei denen noch ein Wachstum zu erwarten ist, Skoliosekorrekturen\\u000a an der Brust- (BWS) und Lendenwirbelsäule (LWS) unter Erhaltung der Wachstumsfähigkeit der Wirbelsäule durchgeführt werden.\\u000a In Abständen von 4–6 Monaten erfolgt das Nachspannen des Doppelstabsystems (Distraktion). Das System bietet die Möglichkeit,\\u000a kleine Patienten, die für ein VEPTR-Instru mentarium (\\

Thomas Pfandlsteiner; Peter Wallnoefer; Cornelius Wimmer

2010-01-01

215

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

216

Genetic selection for body weight in chickens has altered responses of the brain's AMPK system to food intake regulation effect of ghrelin, but not obestatin  

Microsoft Academic Search

The effects of ghrelin and obestatin regulation of food intake are different in mammals and chickens. We investigated central effects of ghrelin and obestatin in lines of chickens selected 50 generations for high (HWS) or low (LWS) body weight. We hypothesized that the effect of ghrelin and obestatin on food intake in 5-day-old chicks is mediated by the AMP-activated protein

Pingwen Xu; Paul B. Siegel; D. Michael Denbow

2011-01-01

217

First detection of far-infrared methane features in Saturn  

Microsoft Academic Search

The Long Wavelength Spectrometer (LWS) is one of four instruments on the ESA Infrared Space Observatory (ISO) satellite. The far-infrared spectrum of Saturn was measured on 16 July 1996, with spectral resolutions of 0.29mu m (43--90mu m) and 0.6mu m (90--197mu m). Weak methane features due to forbidden rotational transitions were detected in absorption against the hydrogen continuum at 106,

G. R. Davis; P. G. Oldham; M. J. Griffin; D. A. Naylor; B. M. Swinyard; P. A. R. Ade; M. Burgdorf; G. S. Orton; S. B. Calcutt; P. G. J. Irwin; D. Gautier; Th. Encrenaz; E. Lellouch; Th. de Graauw

1997-01-01

218

Comparison of fatigue life for 3 types of manual wheelchairs  

Microsoft Academic Search

Fitzgerald SG, Cooper RA, Boninger ML, Rentschler AJ. Comparison of fatigue life for 3 types of manual wheelchairs. Arch Phys Med Rehabil 2001;82:1484-8. Objectives: To examine 3 types of manual wheelchairs[mdash ]ultralight wheelchairs (UWs), lightweight wheelchairs (LWs), and depot wheelchairs (DWs)[mdash ]and to compare the fatigue life between the wheelchair types. Design: A database of different manual wheelchairs tested according

Shirley G. Fitzgerald; Rory A. Cooper; Michael L. Boninger; Andrew J. Rentschler

2001-01-01

219

Broadside Radiation From a Planar 2-D Leaky-Wave Antenna by Practical Surface-Wave Launching  

Microsoft Academic Search

A planar 2-D leaky-wave (LW) antenna, capable of broadside radiation, is presented for millimeter wave applications. A directive surface-wave launcher (SWL) is utilized as the antenna feed exciting cylindrical surface-waves (SWs) on a grounded dielectric slab (GDS). With the addition of a segmented circular strip grating, cylindrical LWs can be excited on the antenna aperture. Measurements illustrate maximum gain at

Symon K. Podilchak; Al P. Freundorfer; Yahia M. M. Antar

2008-01-01

220

Large Wave Simulation of Spilling Breakers Over Immersed Longshore Bar  

Microsoft Academic Search

\\u000a A numerical simulation model is presented for two dimensional wave propagation and breaking. The model is based on Large Wave\\u000a Simulation (LWS) theory for spilling wave breaking. The flow equations are the two-dimensional Euler equations, subject to\\u000a nonlinear free surface boundary conditions. Large scale velocities and free surface elevation are fully resolved and subgrid\\u000a scale effect is modeled by a

Aggelos S. Dimakopoulos; Athanassios A. Dimas

221

Sprinkler protection of manufactured homes with sloped ceilings using prototype limited water supply sprinklers  

Microsoft Academic Search

Three full-scale fire tests were conducted in a commercial manufactured home 4.3 m wide by 18.3 m long with 10° sloped ceilings. The purpose of the tests was to determine the performance of limited water supply (LWS) sprinklers under a sloped ceiling and to determine whether the minimum distance allowed between sprinklers could be reduced from 2.4 m to 1.8

1995-01-01

222

Assessing L?vy walks as models of animal foraging  

PubMed Central

The hypothesis that the optimal search strategy is a Lévy walk (LW) or Lévy flight, originally suggested in 1995, has generated an explosion of interest and controversy. Long-standing empirical evidence supporting the LW hypothesis has been overturned, while new models and data are constantly being published. Statistical methods have been criticized and new methods put forward. In parallel with the empirical studies, theoretical search models have been developed. Some theories have been disproved while others remain. Here, we gather together the current state of the art on the role of LWs in optimal foraging theory. We examine the body of theory underpinning the subject. Then we present new results showing that deviations from the idealized one-dimensional search model greatly reduce or remove the advantage of LWs. The search strategy of an LW with exponent ? = 2 is therefore not as robust as is widely thought. We also review the available techniques, and their potential pitfalls, for analysing field data. It is becoming increasingly recognized that there is a wide range of mechanisms that can lead to the apparent observation of power-law patterns. The consequence of this is that the detection of such patterns in field data implies neither that the foragers in question are performing an LW, nor that they have evolved to do so. We conclude that LWs are neither a universal optimal search strategy, nor are they as widespread in nature as was once thought.

James, Alex; Plank, Michael J.; Edwards, Andrew M.

2011-01-01

223

Neuropeptide Y is associated with changes in appetite-associated hypothalamic nuclei but not food intake in a hypophagic avian model.  

PubMed

While neuropeptide Y (NPY) has been studied extensively per its pronounced role in food intake stimulation as well as its role in central pathways governing eating disorders, it has to our knowledge not been studied in polygenic models of hypo- and hyperphagia. Thus, the present study was designed to measure central NPY-associated food intake in lines of chickens that have undergone long-term genetic selection for low (LWS) or high (HWS) body weight and exhibit hypo- and hyperphagia, respectively. LWS chicks did not respond with any magnitude of altered food intake to any dose of NPY tested, while HWS chicks responded to all doses of NPY at similar magnitudes throughout the duration of observation. Both lines responded with similar increases in c-Fos immunoreactivity in the lateral hypothalamus and both divisions of the paraventricular nucleus; there were no significant line or line by treatment interactions. These data support the hypothesis that differences exist in the central NPY system of chicks from LWS and HWS lines and may provide novel insight for understanding NPY control of appetite. PMID:22921928

Newmyer, Brandon A; Nandar, Wint; Webster, Rebekah I; Gilbert, Elizabeth; Siegel, Paul B; Cline, Mark A

2012-08-17

224

Laboratory of Neural Systems  

Microsoft Academic Search

arrestin-2, rhodopsin (formed by liganding opsin with retinal), and the subunit of the cognate heterotri- nate responses. Since sensitivity to light is built into each target neuron, advance knowledge of its spatial meric G protein—an explosive combination we term \\

Boris V. Zemelman; Georgia A. Lee; Minna Ng; Gero Miesenbock

225

Molecular Cloning of a Rhodopsin Gene From Salamander Rods  

Microsoft Academic Search

Purpose. Salamander photoreceptor cells have been used widely as models in vision research. However, the salamander opsin genes had not been cloned. The purpose of this study was to clone a salamander rhodopsin and to determine its primary structure and cell type-specific expression. Methods. Using salamander retina RNA as a template and Xenopus rhodopsin-specific oligonu- cleotides as primers, reverse transcription

Ning Chen; Jian-xing Ma; D. Wesley; E. Starr Hazard; Rosalie K. Crouch

226

Diurnality and cone photopigment polymorphism in strepsirrhines: examination of linkage in Lemur catta.  

PubMed

Trichromatic color vision is routine among catarrhine primates, but occurs only as a variant form of color vision in some individuals in most platyrrhine genera. This arises from a fundamental difference in the organization of X-chromosome cone opsin genes in these two lineages: catarrhines have two opsin genes specifying middle- and long-wavelength-sensitive cone pigments, while platyrrhines have only a single gene. Some female platyrrhine monkeys achieve trichromacy because of a species polymorphism that allows the possibility of different opsin gene alleles on the two X-chromosomes. Recently, a similar opsin gene polymorphism was detected in some diurnal strepsirrhines, while at the same time appearing to be absent in any nocturnal genera. The aim of this study was to assess whether cone pigment polymorphism is inevitably linked to diurnality in strepsirrhines. Cone photopigments were measured in a species usually classified as diurnal, the ring-tailed lemur (Lemur catta), using electroretinogram flicker photometry, a noninvasive electrophysiological procedure. Each of 12 animals studied was found to have the same middle-wavelength cone pigment, with peak sensitivity at about 547 nm. In conjunction with earlier results, this implies that cone pigment polymorphism is unlikely to exist in this species and that, accordingly, such variation is not a consistently predictable feature of vision in diurnal strepsirrhines. PMID:12923905

Jacobs, Gerald H; Deegan, Jess F

2003-09-01

227

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

228

Cichlid fish visual systems: mechanisms of spectral tuning  

Microsoft Academic Search

Hundreds of species of cichlid fishes have evolved in the Great Lakes of Africa. These colorful fishes are known for their ecological diversity. Here, we discuss the diversity of their visual systems. Cichlids have seven unique cone opsin genes, which produce visual pigments sensitive from the ultraviolet to the red end of the spectrum. Different species typically express three visual

Karen CARLETON

2009-01-01

229

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.

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

230

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

2013-07-17

231

Molecular genetics of rhodopsin and phototrans duction in the visual system of Drosophila  

SciTech Connect

The authors have isolated the genes encoding four Drosophila visual pigments. Each of these opsins is expressed in a set of functionally and anatomically distinct photoreceptor cells of the eye. One is expressed in the six outer photoreceptor cells (R1-R6), the second in the central R8 photoreceptor cell, and the other two in the UV sensitive R7 photoreceptor cells. They have determined the structure and nucleotide sequence of each of these genes. They have used P element-mediated gene transfer to introduce the cloned structural gene for the R1-R6 opsin in the Drosophila germline and restored the ninaE mutant phenotype to wild-type. In an attempt to study the contribution of the various opsins to the specific functional properties of the different photoreceptor cell types, they have genetically engineered Drosophila lines that express R8 opsin in the R1-R6 photoreceptor cells. In collaboration with Drs. Ozaki and Pak at Purdue University, they have used oligonucleotide site-directed mutagenesis to mutate selected amino acids and regions of the rhodopsin molecule and reintroduced the mutated genes into Drosophila to analyze structure-function relationships in the rhodopsin molecule.

Zuker, C.; Cowman, A.; Montell, C.; Rubin, G.

1987-05-01

232

Functional diversity in the color vision of cichlid fishes  

Microsoft Academic Search

BACKGROUND: Color vision plays a critical role in visual behavior. An animal's capacity for color vision rests on the presence of differentially sensitive cone photoreceptors. Spectral sensitivity is a measure of the visual responsiveness of these cones at different light wavelengths. Four classes of cone pigments have been identified in vertebrates, but in teleost fishes, opsin genes have undergone gene

Shai Sabbah; Raico Lamela Laria; Suzanne M Gray; Craig W Hawryshyn

2010-01-01

233

Development of visual cells in the Pacific bluefin tuna Thunnus orientalis.  

PubMed

The development of rod and cone photoreceptor cells was investigated in the retinas of Pacific bluefin tuna larvae and juveniles, using RET-P1 monoclonal antibody labeling to identify photoreceptors. At 60 h after hatching, which was about when feeding began, opsin (presumably green opsin (Rh2)) was expressed in the outer segments of cone cells. At 15 days after hatching (dah), although many labeled cone cells were observed in the dorsal retina, the same type of cone cells had partially appeared in the ventral retina. The presence of rod cell bodies was confirmed by the expression of Rh1 opsin at 15 dah. At 21 dah, the presence of outer segments of rod cells was confirmed by the expression of Rh1 opsin and by morphology. The observations suggest that the cone cells were substantially operable upon the development of their outer segment at around the beginning of the post-larval stage, and the rod cells began to function at around 15 to 21 dah, before and during metamorphosis. PMID:19288257

Matsuura, R; Sawada, Y; Ishibashi, Y

2009-03-15

234

Variation in the Mannose Binding Lectin (MBL) Gene and Susceptibility to Sepsis  

Microsoft Academic Search

A large proportion of the population is exposed to infectious agents and yet few succumb to disease for, as yet, undetermined reasons. Mannose binding lectin (MBL) plays a key role in the host response to infection through the activation of the lectin complement pathway and probably through acting as an opsin. Variations in the level of circulating MBL are observed,

Martin L. Hibberd; John A Summerfield; Michael Levin

2001-01-01

235

Different Transmembrane Domains Associate with Distinct Endoplasmic Reticulum Components during Membrane Integration of a Polytopic Protein  

PubMed Central

We have been studying the insertion of the seven transmembrane domain (TM) protein opsin to gain insights into how the multiple TMs of polytopic proteins are integrated at the endoplasmic reticulum (ER). We find that the ER components associated with the first and second TMs of the nascent opsin polypeptide chain are clearly distinct. The first TM (TM1) is adjacent to the ? and ? subunits of the Sec61 complex, and a novel component, a protein associated with the ER translocon of 10 kDa (PAT-10). The most striking characteristic of PAT-10 is that it remains adjacent to TM1 throughout the biogenesis and membrane integration of the full-length opsin polypeptide. TM2 is also found to be adjacent to Sec61? and Sec61? during its membrane integration. However, TM2 does not form any adducts with PAT-10; rather, a transient association with the TRAM protein is observed. We show that the association of PAT-10 with opsin TM1 does not require the N-glycosylation of the nascent chain and occurs irrespective of the amino acid sequence and transmembrane topology of TM1. We conclude that the precise makeup of the ER membrane insertion site can be distinct for the different transmembrane domains of a polytopic protein. We find that the environment of a particular TM can be influenced by both the “stage” of nascent chain biosynthesis reached, and the TM's relative location within the polypeptide.

Meacock, Suzanna L.; Lecomte, Fabienne J.L.; Crawshaw, Samuel G.; High, Stephen

2002-01-01

236

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

237

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

238

Heterologous Gene Expression in a Membrane-Protein-Specific System  

Microsoft Academic Search

We have constructed an expression system for heterologous proteins which uses the molecular machinery responsible for the high level production of bacteriorhodopsin in Halobacterium salinarum. Cloning vectors were assembled that fused sequences of the bacterio-opsin gene (bop) to coding sequences of heterologous genes and generated DNA fragments with cloning sites that permitted transfer of fused genes into H. salinarum expression

George J. Turner; Regina Reusch; Ann M. Winter-Vann; Lynell Martinez; Mary C. Betlach

1999-01-01

239

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.

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

2011-01-01

240

21 CFR 870.3600 - External pacemaker pulse generator.  

Code of Federal Regulations, 2013 CFR

...permanent pacemaker can be implanted, or to control irregular heartbeats in patients following cardiac surgery or a myocardial infarction. The device may have adjustments for impulse strength, duration, R-wave sensitivity, and other pacing...

2013-04-01

241

For whales and seals the ocean is not blue: a visual pigment loss in marine mammals  

Microsoft Academic Search

Most terrestrial mammals have colour vision based on two spectrally different visual pigments located in two types of retinal cone photoreceptors, i.e. they are cone dichromats with long-to-middle-wave-sensitive (commonly green) L-cones and short-wave- sensitive (commonly blue) S-cones. With visual pigment-specific antibodies, we here demonstrate an absence of S-cones in the retinae of all whales and seals studied. The sample includes

Leo Peichl; Ronald H. H. Kroger

1999-01-01

242

The expression of retinal cell markers in human retinal pigment epithelial cells and their augmentation by the synthetic retinoid fenretinide  

PubMed Central

Purpose In several species the retinal pigment epithelium (RPE) has the potential to transdifferentiate into retinal cells to regenerate functional retinal tissue after injury. However, this capacity for regeneration is lost in mammals. The synthetic retinoic acid derivative, fenretinide [N(4-hydroxyphenyl) retinamide], induces a neuronal-like phenotype in the human adult retinal pigment epithelial cell line (ARPE-19). These changes are characterized by the appearance of neural-like processes and the expression of neuronal markers not normally associated with RPE cells. Here we assess whether fenretinide can induce a neuroretinal cell phenotype in ARPE-19 cells, by examining retinal cell marker expression. Methods ARPE-19 cells were treated daily with culture medium containing either 3 ?M fenretinide or dimethyl sulfoxide as a control for 7 days. Cells were processed for immunocytochemistry, western blotting, and for analysis by PCR to examine the expression of a panel of RPE, neural, and retinal-associated cellular markers, including classical and non-canonical opsins. Results Treatment with fenretinide for 7 days induced the formation of neuronal-like processes in ARPE-19 cells. Fenretinide induced the expression of the cone long wavelength sensitive opsin (OPN1lw) but not rhodopsin (RHO), while decreasing the expression of RPE cell markers. Many of the neuronal and retinal specific markers examined were expressed in both control and fenretinide treated cells, including those involved in photoreceptor cell development and the multipotency of neural retinal progenitor cells. Interestingly, ARPE-19 cells also expressed both photoreceptor specific and non-specific canonical opsins. Conclusions The expression of retinal-associated markers and loss of RPE cell markers in control ARPE-19 cells suggests that these cells might have dedifferentiated from an RPE cell phenotype under standard culture conditions. The expression of molecules, such as the transcription factors paired box 6 gene (PAX6), sex determining region Y-box 2 (SOX2), cone-rod homeobox (CRX), and neural retina leucine zipper (NRL), further implies that in culture these cells are predisposed toward a retinal progenitor-like state. The fenretinide-induced increase in photoreceptor cell markers, accompanied by a decrease in RPE cell markers, suggests that retinoids may play a role in the transdifferentiation of RPE cells. Importantly, our data show for the first time the expression of a vertebrate ciliary opsin (OPN1lw) and rhabdomeric-like opsin, opsin 4 (OPN4 also known as melanopsin) in a clonal cell line. Together these data suggest that ARPE-19 cells are primed for and possess the capacity to differentiate toward a retinal cell-like lineage.

Vugler, Anthony A.; Yu, Lu; Semo, Maayan; Coffey, Pete; Moss, Stephen E.; Greenwood, John

2011-01-01

243

Different k{lambda}{sub D} regimes for nonlinear effects on Langmuir waves  

SciTech Connect

As Langmuir waves (LWs) are driven to large amplitude in plasma, they are affected by nonlinear mechanisms. A global understanding, based on simulations and experiments, has emerged that identifies various nonlinear regimes depending on the dimensionless parameter k{lambda}{sub D}, where k is the Langmuir wave number and {lambda}{sub D} is the electron Debye length. The nonlinear phenomena arise due to wave-wave and wave-particle coupling mechanisms, and this basic separation between fluid-like nonlinearities and kinetic nonlinearities depends on the degree to which electron and ion Landau damping, as well as electron trapping, play a role. Previous ionospheric heating experiments [Cheung et al. Phys. Plasmas 8, 802 (2001)] identified cavitation/collapse and Langmuir decay instability (LDI), predominantly wave-wave mechanisms, to be the principal nonlinear effects for driven LWs with k{lambda}{sub D}<0.1, in agreement with fluid simulations [DuBois et al. Phys. Plasmas 8, 791 (2001)]. In the present research, collective Thomson scattering measurements of LWs driven by stimulated Raman scattering in laser-plasma experiments are used to study both wave-wave and wave-particle nonlinearities [Kline et al. Phys. Rev. Lett. 94, 175003 (2005)]. For k{lambda}{sub D}<0.29, multiple LWs are detected and are attributed to LDI, a wave-wave nonlinear regime. For k{lambda}{sub D}>0.29, a single-wave, frequency-broadened spectrum is observed associated with electron trapping, a wave-particle nonlinear regime. The transition from wave-wave to wave-particle nonlinear behavior is qualitatively consistent with particle-in-cell simulations and with the crossing of the LDI threshold above that for LW self-focusing. The fact that LDI is observed in both ionospheric and laser-plasma experiments for similar values of k{lambda}{sub D}, though vastly differing in plasma conditions and scales, and that simulations predict the various observed nonlinear regimes over a large range of k{lambda}{sub D}, supports our global view of LW nonlinear behavior.

Kline, J.L.; Montgomery, D.S.; Yin, L.; DuBois, D.F.; Albright, B.J.; Bezzerides, B.; Cobble, J.A.; Dodd, E.S.; DuBois, D.F.; Fernandez, J.C.; Johnson, R.P.; Kindel, J.M.; Rose, H.A.; Vu, H.X.; Daughton, W. [Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States); University of California at San Diego, La Jolla, California 92093 (United States); University of Iowa, Iowa City, Iowa 52242 (United States)

2006-05-15

244

Rhabdom evolution in butterflies: insights from the uniquely tiered and heterogeneous ommatidia of the Glacial Apollo butterfly, Parnassius glacialis  

PubMed Central

The eye of the Glacial Apollo butterfly, Parnassius glacialis, a ‘living fossil’ species of the family Papilionidae, contains three types of spectrally heterogeneous ommatidia. Electron microscopy reveals that the Apollo rhabdom is tiered. The distal tier is composed exclusively of photoreceptors expressing opsins of ultraviolet or blue-absorbing visual pigments, and the proximal tier consists of photoreceptors expressing opsins of green or red-absorbing visual pigments. This organization is unique because the distal tier of other known butterflies contains two green-sensitive photoreceptors, which probably function in improving spatial and/or motion vision. Interspecific comparison suggests that the Apollo rhabdom retains an ancestral tiered pattern with some modification to enhance its colour vision towards the long-wavelength region of the spectrum.

Matsushita, Atsuko; Awata, Hiroko; Wakakuwa, Motohiro; Takemura, Shin-ya; Arikawa, Kentaro

2012-01-01

245

Connecting the navigational clock to sun compass input in monarch butterfly brain.  

PubMed

Migratory monarch butterflies (Danaus plexippus) use a time-compensated sun compass to navigate to their overwintering grounds in Mexico. Although polarized light is one of the celestial cues used for orientation, the spectral content (color) of that light has not been fully explored. We cloned the cDNAs of three visual pigment-encoding opsins (ultraviolet [UV], blue, and long wavelength) and found that all three are expressed uniformly in main retina. The photoreceptors of the polarization-specialized dorsal rim area, on the other hand, are monochromatic for the UV opsin. Behavioral studies support the importance of polarized UV light for flight orientation. Next, we used clock protein expression patterns to identify the location of a circadian clock in the dorsolateral protocerebrum of butterfly brain. To provide a link between the clock and the sun compass, we identified a CRYPTOCHROME-staining neural pathway that likely connects the circadian clock to polarized light input entering brain. PMID:15882645

Sauman, Ivo; Briscoe, Adriana D; Zhu, Haisun; Shi, Dingding; Froy, Oren; Stalleicken, Julia; Yuan, Quan; Casselman, Amy; Reppert, Steven M

2005-05-01

246

G Protein-Coupled Receptor Rhodopsin: A Prospectus  

PubMed Central

Rhodopsin is a retinal photoreceptor protein of bipartite structure consisting of the transmembrane protein opsin and a light-sensitive chromophore 11-cis-retinal, linked to opsin via a protonated Schiff base. Studies on rhodopsin have unveiled many structural and functional features that are common to a large and pharmacologically important group of proteins from the G protein-coupled receptor (GPCR) superfamily, of which rhodopsin is the best-studied member. In this work, we focus on structural features of rhodopsin as revealed by many biochemical and structural investigations. In particular, the high-resolution structure of bovine rhodopsin provides a template for understanding how GPCRs work. We describe the sensitivity and complexity of rhodopsin that lead to its important role in vision.

Filipek, Slawomir; Stenkamp, Ronald E.; Teller, David C.; Palczewski, Krzysztof

2006-01-01

247

Evidence from Chlamydomonas on the photoactivation of rhodopsins without isomerization of their chromophore  

PubMed Central

SUMMARY Attachment of retinal to opsin forms the chromophore N-retinylidene which isomerizes during photoactivation of rhodopsins. To test whether isomerization is crucial, custom-tailored chromophores lacking the ?-ionone ring and any isomerizable bonds were incorporated in vivo into the opsin of a blind mutant of the eukaryote Chlamydomonas reinhardtii. The analogues restored phototaxis with the anticipated action spectra, ruling out the need for isomerization in photoactivation. To further elucidate photoactivation, responses to chromophores formed from naphthalene aldehydes were studied. The resulting action spectral shifts suggest that charge separation within the excited chromophore leads to electric field induced polarization of nearby amino-acid residues and altered hydrogen bonding. This redistribution of charge faciliates the reported multiple bond rotations and protein rearrangements of rhodopsin activation. These results provide new insight into the activation of rhodopsins and related GPCRs.

Foster, Kenneth W.; Saranak, Jureepan; Krane, Sonja; Johnson, Randy L.; Nakanishi, Koji

2011-01-01

248

A comprehensive multiscale framework for simulating optogenetics in the heart.  

PubMed

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 multiscale 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 thresholds. PMID:23982300

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

2013-08-28

249

Two-photon optogenetic toolbox for fast inhibition, excitation and bistable modulation.  

PubMed

Optogenetics with microbial opsin genes has enabled high-speed control of genetically specified cell populations in intact tissue. However, it remains a challenge to independently control subsets of cells within the genetically targeted population. Although spatially precise excitation of target molecules can be achieved using two-photon laser-scanning microscopy (TPLSM) hardware, the integration of two-photon excitation with optogenetics has thus far required specialized equipment or scanning and has not yet been widely adopted. Here we take a complementary approach, developing opsins with custom kinetic, expression and spectral properties uniquely suited to scan times typical of the raster approach that is ubiquitous in TPLSMlaboratories. We use a range of culture, slice and mammalian in vivo preparations to demonstrate the versatility of this toolbox, and we quantitatively map parameter space for fast excitation, inhibition and bistable control. Together these advances may help enable broad adoption of integrated optogenetic and TPLSMtechnologies across experimental fields and systems. PMID:23169303

Prakash, Rohit; Yizhar, Ofer; Grewe, Benjamin; Ramakrishnan, Charu; Wang, Nancy; Goshen, Inbal; Packer, Adam M; Peterka, Darcy S; Yuste, Rafael; Schnitzer, Mark J; Deisseroth, Karl

2012-12-01

250

Two-photon optogenetics of dendritic spines and neural circuits in 3D  

PubMed Central

We demonstrate a two-photon optogenetic method that generates action potentials in neurons with single-cell precision, using the red-shifted opsin C1V1T. We apply the method to optically map synaptic circuits in mouse neocortical brain slices and to activate small dendritic regions and individual spines. Using a spatial light modulator we split the laser beam onto several neurons and perform simultaneous optogenetic activation of selected neurons in three dimensions.

Packer, Adam M.; Peterka, Darcy S.; Hirtz, Jan J.; Prakash, Rohit; Deisseroth, Karl; Yuste, Rafael

2012-01-01

251

A Constitutively Activating Mutation Alters the Dynamics and Energetics of a Key Conformational Change in a Ligand-free G Protein-coupled Receptor.  

PubMed

G protein-coupled receptors (GPCRs) undergo dynamic transitions between active and inactive conformations. Usually, these conversions are triggered when the receptor detects an external signal, but some so-called constitutively activating mutations, or CAMs, induce a GPCR to bind and activate G proteins in the absence of external stimulation, in ways still not fully understood. Here, we investigated how a CAM alters the structure of a GPCR and the dynamics involved as the receptor transitions between different conformations. Our approach used site-directed fluorescence labeling (SDFL) spectroscopy to compare opsin, the ligand-free form of the GPCR rhodopsin, with opsin containing the CAM M257Y, focusing specifically on key movements that occur in the sixth transmembrane helix (TM6) during GPCR activation. The site-directed fluorescence labeling data indicate opsin is constrained to an inactive conformation both in detergent micelles and lipid membranes, but when it contains the M257Y CAM, opsin is more dynamic and can interact with a G protein mimetic. Further study of these receptors using tryptophan-induced quenching (TrIQ) methods indicates that in detergent, the CAM significantly increases the population of receptors in the active state, but not in lipids. Subsequent Arrhenius analysis of the TrIQ data suggests that, both in detergent and lipids, the CAM lowers the energy barrier for TM6 movement, a key transition required for conversion between the inactive and active conformations. Together, these data suggest that the lowered energy barrier is a primary effect of the CAM on the receptor dynamics and energetics. PMID:23940032

Tsukamoto, Hisao; Farrens, David L

2013-08-12

252

L, M and LM hybrid cone photopigments in man: deriving lmax from flicker photometric spectral sensitivities  

Microsoft Academic Search

Using heterochromatic flicker photometry, we have measured the corneal spectral sensitivities of the X-chromosome-linked photopigments in 40 dichromats, 37 of whom have a single opsin gene in their tandem array. The photopigments encoded by their genes include: the alanine variant of the normal middle-wavelength sensitive photopigment, M(A180); the alanine and serine variants of the normal long-wavelength sensitive photopigment, L(A180) and

Lindsay T. Sharpe; Andrew Stockman; Herbert Jagle; Holger Knau; Jeremy Nathans

253

L, M and L–M hybrid cone photopigments in man: deriving ? max from flicker photometric spectral sensitivities  

Microsoft Academic Search

Using heterochromatic flicker photometry, we have measured the corneal spectral sensitivities of the X-chromosome-linked photopigments in 40 dichromats, 37 of whom have a single opsin gene in their tandem array. The photopigments encoded by their genes include: the alanine variant of the normal middle-wavelength sensitive photopigment, M(A180); the alanine and serine variants of the normal long-wavelength sensitive photopigment, L(A180) and

Lindsay T. Sharpe; Andrew Stockman; Herbert Jägle; Holger Knau; Jeremy Nathans

1999-01-01

254

Effect of color vision phenotype on the foraging of wild white-faced capuchins, Cebus capucinus  

Microsoft Academic Search

New World monkeys exhibit a color vision polymorphism. It results from allelic variation of the single-locus middle-to-long wavelength opsin gene on the X chromosome. Females that are heterozygous for the gene possess trichromatic vision. All other individuals possess dichromatic vision. The prevailing hypothesis for the maintenance of the color vision polymorphism is through a consistent fitness advantage to heterozygous trichromatic

Erin R. Vogel; Maureen Neitz; N. J. Dominy

2006-01-01

255

Functional diversity of melanopsins and their global expression in the teleost retina  

Microsoft Academic Search

Melanopsin (OPN4) is an opsin photopigment that, in mammals, confers photosensitivity to retinal ganglion cells and regulates\\u000a circadian entrainment and pupil constriction. In non-mammalian species, two forms of opn4 exist, and are classified into mammalian-like (m) and non-mammalian-like (x) clades. However, far less is understood of the function of this photopigment family. Here we identify in zebrafish five\\u000a melanopsins (opn4m-1,

Wayne I. L. Davies; Lei Zheng; Steven Hughes; T. Katherine Tamai; Michael Turton; Stephanie Halford; Russell G. Foster; David Whitmore; Mark W. Hankins

256

Phylogeny of Halictidae with an emphasis on endemic African Halictinae  

Microsoft Academic Search

We review the literature on phylogeny, fossil record, biogeography, and social evolution in Halictidae. We then present a\\u000a phylogenetic analysis of tribal, generic, and subgeneric relationships within the subfamily Halictinae using a combined data\\u000a set of three nuclear genes: long-wavelength (LW) opsin, wingless, and EF-1?. The data set includes 89 species in 34 genera representing all four halictid subfamilies, and

Bryan N. Danforth; Connal Eardley; Laurence Packer; Kenneth Walker; Alain Pauly; Fano José Randrianambinintsoa

2008-01-01

257

Influence of carotenoid deficiency on visual sensitivity, visual pigment and P-face particles of photoreceptor membrane in the moth Manduca sexta  

Microsoft Academic Search

1.Several larval diets (Table 1) were developed for rearing the tobacco hornworm mothManduca sexta in an effort to control the synthesis of adult visual pigments (generically, ‘rhodopsins’) through the availability of their chromophore, retinaldehyde or, more likely, 3-hydroxyretinaldehyde.2.Rhodopsin was measured in difference spectra from detergent extracts of adult retinas. Opsin was identified and measured on SDS gels after electrophoretic separation

Ruth R. Bennett; Richard H. White

1989-01-01

258

New Insights into the Evolutionary History of Type 1 Rhodopsins  

Microsoft Academic Search

Type 1 (archaeal) rhodopsins and related rhodopsin-like proteins had been described in a few halophile archaea, ?-proteobacteria, a single cyanobacteria, some fungi, and a green alga. In exhaustive database searches, we detected rhodopsin-related sequences derived not only from additional fungal species but also from organisms belonging to three groups in which opsins had hitherto not been described: the a-proteobacterium Magnetospirillummagnetotacticum,

Mario X. Ruiz-González; Ignacio Marín

2004-01-01

259

A molecular phylogeny of the Old World stingless bees (Hymenoptera: Apidae: Meliponini) and the non-monophyly of the large genus Trigona  

Microsoft Academic Search

We examined the inter- and infrageneric relationships of Old World Meliponini with a near-complete sampling of supra-specific taxa. DNA sequences for the taxa were collected from four genes (mitochondrial 16S rRNA, nuclear long-wavelength rhodopsin copy 1 (opsin), elongation factor-1a copy F2 and arginine kinase). Additional sampling of New World taxa indicated that Trigona sensu lato is not monophyletic: Trigona from

CLAUS R ASMUSSEN; A. C AMERON

2007-01-01

260

A Maximum-Likelihood Analysis of Eight Phylogenetic Markers in Gallwasps (Hymenoptera: Cynipidae): Implications for Insect Phylogenetic Studies  

Microsoft Academic Search

We assessed the utility of eight DNA sequence markers (5.8S rDNA, 18S rDNA, 28S rDNA, ITS regions, long-wavelength opsin, elongation factor 1-?, 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

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

2002-01-01

261

A rhodopsin-like protein in the plasma membrane of Silvetia compressa eggs.  

PubMed

Unidirectional blue light directs the rhizoid-thallus axis in the apolar zygote of the brown alga, Silvetia compressa. This effect is mediated by an increase in the intracellular concentration of guanosine 3', 5'-cyclic monophosphate. In this study we show the identification of a rhodopsin-like protein, by means of antibody reaction, in the plasma membrane of Silvetia eggs. This new result suggests a role for opsins in Silvetia photopolarity. PMID:11837330

Gualtieri, Paolo; Robinson, Kenneth R

2002-01-01

262

THE ROLE OF SULFHYDRYL GROUPS IN THE BLEACHING AND SYNTHESIS OF RHODOPSIN  

PubMed Central

The condensation of retinene1 with opsin to form rhodopsin is optimal at pH about 6, a pH which favors the condensation of retinene1 with sulfhydryl rather than with amino groups. The synthesis of rhodopsin, though unaffected by the less powerful sulfhydryl reagents, monoiodoacetic acid and its amide, is inhibited completely by p-chloromercuribenzoate (PCMB). This inhibition is reversed in part by the addition of glutathione. PCMB does not attack rhodopsin itself, nor does it react with retinene1. Its action in this system is confined to the —SH groups of opsin. Under some conditions the synthesis of rhodopsin is aided by the presence of such a sulfhydryl compound as glutathione, which helps to keep the —SH groups of opsin free and reduced. By means of the amperometric silver titration of Kolthoff and Harris, it is shown that sulfhydryl groups are liberated in the bleaching of rhodopsin, two such groups for each retinene1 molecule that appears. This is true equally of rhodopsin from the retinas of cattle, frogs) and squid. The exposure of new sulfhydryl groups adds an important element to the growing evidence that relates the bleaching of rhodopsin to protein denaturation. The place of sulfhydryl groups in the structure of rhodopsin is still uncertain. They may be concerned directly in binding the chromophore to opsin; or alternatively they may furnish hydrogen atoms for some reductive change by which the chromophore is formed from retinene1. In the amperometric silver titration, the bleaching of rhodopsin yields directly an electrical variation. This phenomenon may have some fundamental connection with the role of rhodopsin in visual excitation, and may provide a model of the excitation process in general.

Wald, George; Brown, Paul K.

1952-01-01

263

Channelrhodopsin-1: A Light-Gated Proton Channel in Green Algae  

Microsoft Academic Search

Phototaxis and photophobic responses of green algae are mediated by rhodopsins with microbial-type chromophores. We report a complementary DNA sequence in the green alga Chlamydomonas reinhardtii that encodes a microbial opsin-related protein, which we term Channelopsin-1. The hydrophobic core region of the protein shows homology to the light-activated proton pump bacteriorhodopsin. Expression of Channelopsin-1, or only the hydrophobic core, in

Georg Nagel; Doris Ollig; Markus Fuhrmann; Suneel Kateriya; Anna Maria Musti; Ernst Bamberg; Peter Hegemann

2002-01-01

264

Physiological characterization of the compound eye in monarch butterflies with focus on the dorsal rim area  

Microsoft Academic Search

The spectral, angular and polarization sensitivities of photoreceptors in the compound eye of the monarch butterfly (Danaus plexippus) are examined using electrophysiological methods. Intracellular recordings reveal a spectrally homogenous population of UV\\u000a receptors with optical axes directed upwards and ?10° to the contralateral side. Based on optical considerations and on the\\u000a opsin expression pattern (Sauman et al. 2005), we conclude

Julia Stalleicken; Thomas Labhart; Henrik Mouritsen

2006-01-01

265

Comparative retinal morphology of the platypus.  

PubMed

The purpose of this study is to identify evolutionary origin and fate of anatomic features of the duck-billed platypus eye. Eyes from the duck-billed platypus and four key evolutionary basal vertebrates (Pacific hagfish, north hemisphere sea lamprey, and Australian and South American lungfishes) were prepared for light microscopy. In addition to a standard panel of stains, tissues were immunostained against a variety of rod and cone opsins. Finally, published opsin sequences of platypus and several other vertebrate species were aligned and compared with immunohistochemical results. A complete scleral cartilage similar to that seen in birds, reptiles and amphibians encloses the platypus eye. This feature is present in sharks and rays, and in extant relatives of tetrapods, the lungfishes. The choroid lacks a tapetum. The retina is largely avascular and is rod-dominated, with a minority of red- and blue- cone immunoreactive photoreceptors. Like marsupials and many nonmammalian vertebrates, cones contain clear inner segment droplets. Double cones were present, a feature not found in eutherian mammals or marsupials. Evaluation of opsins indicates that red and blue immunoreactive cone opsins, but not rhodopsin, are present in the most basal of the extant species examined, the Pacific hagfish. Rhodopsin appears in the Australian and South American lungfishes, establishing emergence of this pigment in an extant relative of tetrapods. Unlike eyes of eutherian mammals, the platypus eye has retained morphologic features present in early tetrapods such as amphibians and their evolutionarily basal sister group, the lungfishes. These include scleral cartilage, double cones and cone droplets. In the platypus, as in other mammals, rod rhodopsin is the predominant photoreceptor pigment, at expense of the cone system. PMID:21567446

Zeiss, Caroline J; Schwab, Ivan R; Murphy, Christopher J; Dubielzig, Richard W

2011-05-12

266

The Molecular Evolution of Visual Pigments of Freshwater Crayfishes (Decapoda: Cambaridae)  

Microsoft Academic Search

.   This study examines the diverse maximum wavelength absorption (?max) found in crayfishes (Decapoda: Cambaridae and Parastacidae) and the associated genetic variation in their opsin locus. We\\u000a measured the wavelength absorption in the photoreceptors of six species that inhabit environments of different light intensities\\u000a (i.e., burrows, streams, standing waters, and subterranean waters). Our results indicate that there is relatively little

Keith A. Crandall; Thomas W. Cronin

1997-01-01

267

Effect of color vision phenotype on the foraging of wild white-faced capuchins, Cebus capucinus  

Microsoft Academic Search

New World monkeys exhibit a color vision polymorphism. It results from allelic variation of the single-locus middle-to-long wavelength opsin gene on the X chromosome. Females that are heterozygous for the gene possess trichromatic vision. All other individuals possess dichromatic vision. The prevailing hypothesis for the maintenance of the color vision polymorphism is through a consistent fitness advantage to heterozygous trichromatic

Erin R. Vogel; Maureen Neitz; Nathaniel J. Dominy

2007-01-01

268

Rpe65 Isomerase Associates with Membranes through an Electrostatic Interaction with Acidic Phospholipid Headgroups*  

PubMed Central

Opsins are light-sensitive pigments in the vertebrate retina, comprising a G protein-coupled receptor and an 11-cis-retinaldehyde chromophore. Absorption of a photon by an opsin pigment induces isomerization of its chromophore to all-trans-retinaldehyde. After a brief period of activation, opsin releases all-trans-retinaldehyde and becomes insensitive to light. Restoration of light sensitivity to the apo-opsin involves the conversion of all-trans-retinaldehyde back to 11-cis-retinaldehyde via an enzyme pathway called the visual cycle. The critical isomerization step in this pathway is catalyzed by Rpe65. Rpe65 is strongly associated with membranes but contains no membrane-spanning segments. It was previously suggested that the affinity of Rpe65 for membranes is due to palmitoylation of one or more Cys residues. In this study, we re-examined this hypothesis. By two independent strategies involving mass spectrometry, we show that Rpe65 is not palmitoylated nor does it appear to undergo other post-translational modifications at significant stoichiometry. Instead, we show that Rpe65 binds the acidic phospholipids, phosphatidylserine, phosphatidylglycerol, and cardiolipin, but not phosphatidic acid. No binding of Rpe65 to basic phospholipids or neutral lipids was observed. The affinity of Rpe65 to acidic phospholipids was strongly pH-dependent, suggesting an electrostatic interaction of basic residues in Rpe65 with negatively charged phospholipid headgroups. Binding of Rpe65 to liposomes containing phosphatidylserine or phosphatidylglycerol, but not the basic or neutral phospholipids, allowed the enzyme to extract its insoluble substrate, all-trans-retinyl palmitate, from the lipid bilayer for synthesis of 11-cis-retinol. The interaction of Rpe65 with acidic phospholipids is therefore biologically relevant.

Yuan, Quan; Kaylor, Joanna J.; Miu, Anh; Bassilian, Sara; Whitelegge, Julian P.; Travis, Gabriel H.

2010-01-01

269

Coexpression of Two Visual Pigments in a Photoreceptor Causes an Abnormally Broad Spectral Sensitivity in the Eye of the Butterfly Papilio xuthus  

Microsoft Academic Search

The compound eye of the butterfly Papilio xuthus consists of three different types of ommatidia, each containing nine photoreceptor cells (R1-R9). We have found previously that the R5-R8 photoreceptors of type II ommatidia coexpress two different mRNAs, encoding opsins of green- and orange-red-absorbing visual pigments (Kitamoto et al., 1998). Do these cells contain two functionally distinct visual pigments? First, we

Kentaro Arikawa; Shin Mizuno; Michiyo Kinoshita; Doekele G. Stavenga

2003-01-01

270

QM/MM trajectory surface hopping approach to photoisomerization of rhodopsin and isorhodopsin: the origin of faster and more efficient isomerization for rhodopsin.  

PubMed

The photoinduced cis-trans isomerization dynamics of rhodopsin and isorhodopsin are studied using a newly developed hybrid QM/MM trajectory surface hopping MD scheme based on the Zhu-Nakamura theory for nonadiabatic transitions. Rhodopsin and isorhodopsin have 11-cis and 9-cis forms of retinal as chromophore and the two proteins are isomerized to bathorhodopsin enclosing the all-trans form. The simulation reproduced faster and more efficient isomerization in rhodopsin than in isorhodopsin. In the excited state, rhodopsin shows a straightforward dynamics, whereas isorhodopsin dynamics is rather complicated and in a back-and-forth manner. The latter complicated dynamics would be mainly due to a narrow space near the active dihedral angle ?C8-C9?C10-C11? (?9) created by Thr 118 and Tyr 268 in opsin. Rhodopsin gives bathorhodopsin only while isorhodopsin yields a byproduct. The rigorous selectivity in rhodopsin would be another reason why rhodopsin is selected biologically. Comparison with our previous opsin-free investigations reveals that opsin tends to confine the twist of the active dihedral to only one direction and funnels transitions into the vicinity of minimum energy conical intersections (MECI). The twist-confinement totally blocks simultaneous twisting of ?9 and ?11 (?C10-C11?C12-C13?) and enhances the quantum yields. The opposite rotation of ?9 and ?11 ("wring-a-wet-towel" motion) takes place upon photoexcitation, which also does without opsin. The wring-a-wet-towel motion is dynamically enhanced in comparison with the one expected from locations of the MECI. The present simulation reveals that the Weiss-Warshel model for cis-trans photoisomerization is not applicable for rhodopsin because the branching ratio after transition is crucial. PMID:22783826

Chung, Wilfredo Credo; Nanbu, Shinkoh; Ishida, Toshimasa

2012-07-11

271

Primary structure of C-terminal functional sites in ovine rhodopsin  

Microsoft Academic Search

Rhodopsin is the primary photoreceptor protein in the vertebrate retina. The functional complex consists of the polypeptide, opsin, to which is bound a molecule of 11-cis-retinal. An absorbed photon of light induces electronic changes in this chromophore, resulting in its isomerization to the all-trans form1 and the triggering of a series of spectrally-defined con-formational changes in the protein. This `activation'

John B. C. Findlay; Michael Brett; Darryl J. C. Pappin

1981-01-01

272

Expression of ?2-adrenoceptors in halobacteria  

Microsoft Academic Search

Halobacteria are halophilic representatives of the recently defined domain, the Archaea. Halobacterium salinarium belongs to this group of microorganisms and contains large amounts of bacteriorhodopsin in its membrane. Bacteriorhodopsin\\u000a is a seven-transmembrane protein that consists of bacterio-opsin (BO), and the chromophore retinal, which is covalently attached\\u000a to BO. We have investigated whether the expression machinery for BO can be utilized

P. Söhlemann; Jörg Soppa; Dieter Oesterhelt; Martin J. Lohse

1997-01-01

273

Light Induction of a Vertebrate Clock Gene Involves Signaling through Blue-Light Receptors and MAP Kinases  

Microsoft Academic Search

The signaling pathways that couple light photoreception to entrainment of the circadian clock have yet to be deciphered. Two prominent groups of candidates for the circadian photoreceptors are opsins (e.g., melanopsin) and blue-light photoreceptors (e.g., cryptochromes). We have previously showed that the zebrafish is an ideal model organism in which to study circadian regulation and light response in peripheral tissues.

Nicolas Cermakian; Matthew P Pando; Carol L Thompson; Anna B Pinchak; Christopher P Selby; Laura Gutierrez; Dan E Wells; Gregory M Cahill; Aziz Sancar; Paolo Sassone-Corsi

2002-01-01

274

Nonuniform Distribution and Spectral Tuning of Photosensitive Retinal Ganglion Cells of the Mouse Retina  

PubMed Central

Summary Melanopsin-expressing photosensitive retinal ganglion cells (pRGCs) represent a third class of retinal photoreceptor [1–3]. These cells are intrinsically photosensitive, but also receive inputs from rod and cone photoreceptors [4–7], acting as the primary sensory conduit mediating non-image-forming responses to light [8–11]. Multiple subtypes of pRGC have been described in the mouse retina with characteristic morphologies and functional properties, and which perform distinct physiological roles [12–15]. Here, we examine the levels of melanopsin expression and distribution of pRGC subtypes across the mouse retina, identifying a previously unreported anatomical and functional specialization of the melanopsin system. Our results show a dorsal-ventral gradient in the expression of melanopsin and the distribution of pRGCs, which, combined with dorsal-ventral gradients in ultraviolet-sensitive and medium-wavelength-sensitive cone opsin expression, produce dramatic variations in the ratio of cone opsins and pRGCs across the retina. Using c-fos expression as a marker of light activation in vivo [16–18], we show that the responses of pRGCs are spectrally tuned by gradients in cone opsin expression depending on their location in the retina. These data illustrate the importance of classical photoreceptors in providing spectral tuning of pRGC light responses and have important implications for the complexity of non-image-forming responses to light.

Hughes, Steven; Watson, Thomas S.; Foster, Russell G.; Peirson, Stuart N.; Hankins, Mark W.

2013-01-01

275

Identification of DES1 as a Vitamin A Isomerase in M?ller Glial Cells of the Retina  

PubMed Central

Absorption of a light particle by an opsin-pigment causes photoisomerization of its retinaldehyde chromophore. Restoration of light sensitivity to the resulting apo-opsin requires chemical re-isomerization of the photobleached chromophore. This is carried out by a multistep enzyme pathway called the visual cycle. Accumulating evidence suggests the existence of an alternate visual cycle for regenerating opsins in daylight. Here, we identified dihydroceramide desaturase-1 (DES1) as a retinol isomerase and an excellent candidate for isomerase-2 in this alternate pathway. DES1 is expressed in retinal Müller cells where it co-immunoprecipitates with cellular retinaldehyde binding protein (CRALBP). Adenoviral gene therapy with DES1 partially rescued the biochemical and physiological phenotypes in rpe65 ?/? mice lacking isomerohydrolase (isomerase-1). Knockdown of DES1 expression by RNA-interference concordantly reduced isomerase-2 activity in cultured Müller cells. Purified DES1 possessed very high isomerase-2 activity in the presence of appropriate cofactors, suggesting that DES1 by itself is sufficient for isomerase activity.

Kaylor, Joanna J.; Yuan, Quan; Cook, Jeremy; Sarfare, Shanta; Makshanoff, Jacob; Miu, Anh; Kim, Anita; Kim, Paul; Habib, Samer; Roybal, C. Nathaniel; Xu, Tongzhou; Nusinowitz, Steven; Travis, Gabriel H.

2012-01-01

276

Spectral sensitivity of the ctenid spider Cupiennius salei.  

PubMed

The spectral sensitivity of adult male Cupiennius salei Keys, a nocturnal hunting spider, was studied in a behavioural test. As known from earlier behavioural tests, C. salei will walk towards a black target presented in front of a white background. In this study, a black target (size 42×70 cm) was presented in a white arena illuminated by monochromatic light in the range 365-695 nm using 19 monochromatic filters (half-width in the range 6-10 nm). In the first trial, the transmission of the optical filters was between 40% and 80%. In the second trial, the transmission was reduced to 5% using a neutral density filter. At the high intensity, the spiders showed a spectral sensitivity in the range 380-670 nm. In the second trial, the animals only showed directed walks if the illumination was in the range 449-599 nm, indicating a lower sensitivity at the margins of the spectral sensitivity. In previous intracellular recordings, the measured spectral sensitivity was between 320 and 620 nm. Interestingly, these results do not completely match the behaviourally tested spectral sensitivity of the photoreceptors, where the sensitivity range is shifted to longer wavelengths. In order to investigate the molecular background of spectral sensitivity, we searched for opsin genes in C. salei. We found three visual opsins that correspond to UV and middle to long wavelength sensitive opsins as described for jumping spiders. PMID:23948480

Zopf, Lydia M; Schmid, Axel; Fredman, David; Eriksson, Bo Joakim

2013-08-15

277

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.

Sekharan, Sivakumar; Yokoyama, Shozo

2011-01-01

278

Eyes with basic dorsal and specific ventral regions in the glacial Apollo, Parnassius glacialis (Papilionidae).  

PubMed

Recent studies on butterflies have indicated that their colour vision system is almost species specific. To address the question of how this remarkable diversity evolved, we investigated the eyes of the glacial Apollo, Parnassius glacialis, a living fossil species belonging to the family Papilionidae. We identified four opsins in the Parnassius eyes--an ultraviolet- (PgUV), a blue- (PgB), and two long wavelength (PgL2, PgL3)-absorbing types--and localized their mRNAs within the retina. We thus found ommatidial heterogeneity and a clear dorso-ventral regionalization of the eye. The dorsal region consists of three basic types of ommatidia that are similar to those found in other insects, indicating that this dorsal region retains the ancestral state. In the ventral region, we identified two novel phenomena: co-expression of the opsins of the UV- and B-absorbing type in a subset of photoreceptors, and subfunctionalization of long-wavelength receptors in the distal tier as a result of differential expression of the PgL2 and PgL3 mRNAs. Interestingly, butterflies from the closely related genus Papilio (Papilionidae) have at least three long-wavelength opsins, L1-L3. The present study indicates that the duplication of L2 and L3 occurred before the Papilio lineage diverged from the rest, whereas L1 was produced from L3 in the Papilio lineage. PMID:21075944

Awata, Hiroko; Matsushita, Atsuko; Wakakuwa, Motohiro; Arikawa, Kentaro

2010-12-01

279

The pineal organ is the first differentiated light receptor in the embryonic salmon, Salmo salar L.  

PubMed

The initial appearance of S-antigen, alpha-transducin, opsin and 5-HT during embryogenesis of the pineal organ and retina was studied by means of immunocytochemistry in the Atlantic salmon, Salmo salar L. The presence of these substances may be taken as a good indication of photoreceptor differentiation; alpha-transducin and S-antigen are involved in the phototransduction process, opsin is the proteinaceous component of the photopigment rhodopsin, and 5-HT is a neurotransmitter or neurohormone produced by pineal photoreceptors. Two days after the retinal pigment layer became visible in the eggs, the outer segments of a few pineal photosensory cells showed immunoreactivity to opsin and alpha-transducin. At the same time S-antigen and serotonin were present in pineal cells of the photoreceptor type. The number of immunoreactive cells in the pineal organ increased up to hatching. In the differentiating retina of the salmon, no immunoreactivity to antibodies raised against the mentioned substances were detectable until after hatching. These results indicate that in ontogeny the developing pineal organ of the salmon embryo has the ability to perceive light information much earlier than the retina. PMID:2959366

Ostholm, T; Brännäs, E; van Veen, T

1987-09-01

280

Nonuniform distribution and spectral tuning of photosensitive retinal ganglion cells of the mouse retina.  

PubMed

Melanopsin-expressing photosensitive retinal ganglion cells (pRGCs) represent a third class of retinal photoreceptor [1-3]. These cells are intrinsically photosensitive, but also receive inputs from rod and cone photoreceptors [4-7], acting as the primary sensory conduit mediating non-image-forming responses to light [8-11]. Multiple subtypes of pRGC have been described in the mouse retina with characteristic morphologies and functional properties, and which perform distinct physiological roles [12-15]. Here, we examine the levels of melanopsin expression and distribution of pRGC subtypes across the mouse retina, identifying a previously unreported anatomical and functional specialization of the melanopsin system. Our results show a dorsal-ventral gradient in the expression of melanopsin and the distribution of pRGCs, which, combined with dorsal-ventral gradients in ultraviolet-sensitive and medium-wavelength-sensitive cone opsin expression, produce dramatic variations in the ratio of cone opsins and pRGCs across the retina. Using c-fos expression as a marker of light activation in vivo [16-18], we show that the responses of pRGCs are spectrally tuned by gradients in cone opsin expression depending on their location in the retina. These data illustrate the importance of classical photoreceptors in providing spectral tuning of pRGC light responses and have important implications for the complexity of non-image-forming responses to light. PMID:23954426

Hughes, Steven; Watson, Thomas S; Foster, Russell G; Peirson, Stuart N; Hankins, Mark W

2013-08-15

281

Evolution of Vision  

NASA Astrophysics Data System (ADS)

The evolution of photoreception, giving rise to eye, offers a kaleidoscopic view on selection acting at both the organ and molecular levels. The molecular level is mainly considered in the lecture. The greatest progress to date has been made in relation to the opsin visual pigments. Opsins appeared before eyes did. Two- and three-dimensional organization for rhodopsin in the rod outer segment disk membrane, as well as molecular mechanisms of visual pigments spectral tuning, photoisomerization and also opsin as a G-protein coupled receptor are considered. Molecular mechanisms of visual pigments spectral tuning, namely switching of chromophore (physiological time scale) and amino acid changes in the chromophore site of opsin (evolutionary time scale) is considered in the lecture. Photoisomerization of rhodopsin chromophore, 11-cis retinal is the only photochemical reaction in vision. The reaction is extemely fast (less that 200 fs) and high efficient (. is 0.65). The rhodopsin photolysis and kinetics of the earlier products appearance, photo- and bathorhodopsin, is considered. It is known that light is not only a carrier of information, but also a risk factor of damage to the eye. This photobiological paradox of vision is mainly due to the nature of rhodopsin chromophore. Photooxidation is the base of the paradox. All factors present in the phototrceptor cells to initiate free-radical photooxidation: photosensitizers, oxygen and substrates of oxidation: lipids and proteins (opsin). That is why photoprotective system of the eye structures appeared in the course of evolution. Three lines of protective system to prevent light damage to the retina and retina pigment epithelium is known: permanent renewal of rod and cone outer segment, powerful antioxidant system and optical media as cut-off filters where the lens is a key component. The molecular mechanisms of light damage to the eye and photoprotective system of the eye is considered in the lecture. The molecular mechanisms of phototransduction in vertebrates eye is also briefly considered in the lecture. Evolution of vision is an enormous subject for thought and investigation. In the postgenomic era evolutionary molecular physiology as a whole and evolutionary molecular physiology of vision can be considered as a key approach for understanding how genome is working.

Ostrovsky, Mikhail

282

Functional diversity in the color vision of cichlid fishes  

PubMed Central

Background Color vision plays a critical role in visual behavior. An animal's capacity for color vision rests on the presence of differentially sensitive cone photoreceptors. Spectral sensitivity is a measure of the visual responsiveness of these cones at different light wavelengths. Four classes of cone pigments have been identified in vertebrates, but in teleost fishes, opsin genes have undergone gene duplication events and thus can produce a larger number of spectrally distinct cone pigments. In this study, we examine the question of large-scale variation in color vision with respect to individual, sex and species that may result from differential expression of cone pigments. Cichlid fishes are an excellent model system for examining variation in spectral sensitivity because they have seven distinct cone opsin genes that are differentially expressed. Results To examine the variation in the number of cones that participate in cichlid spectral sensitivity, we used whole organism electrophysiology, opsin gene expression and empirical modeling. Examination of over 100 spectral sensitivity curves from 34 individuals of three species revealed that (1) spectral sensitivity of individual cichlids was based on different subsets of four or five cone pigments, (2) spectral sensitivity was shaped by multiple cone interactions and (3) spectral sensitivity differed between species and correlated with foraging mode and the spectral reflectance of conspecifics. Our data also suggest that there may be significant differences in opsin gene expression between the sexes. Conclusions Our study describes complex opponent and nonopponent cone interactions that represent the requisite neural processing for color vision. We present the first comprehensive evidence for pentachromatic color vision in vertebrates, which offers the potential for extraordinary spectral discrimination capabilities. We show that opsin gene expression in cichlids, and possibly also spectral sensitivity, may be sex-dependent. We argue that females and males sample their visual environment differently, providing a neural basis for sexually dimorphic visual behaviour. The diversification of spectral sensitivity likely contributes to sensory adaptations that enhance the contrast of transparent prey and the detection of optical signals from conspecifics, suggesting a role for both natural and sexual selection in tuning color vision.

2010-01-01

283

TCP-SuperCharger : A New Approach to High-Throughput Satellite Data Transfer  

NASA Astrophysics Data System (ADS)

It is well-known that TCP does not perform well in modern satellite-based communications due to the channel's very large bandwidth-delay product. The conventional solution is to make use of TCP's Large Window Scale (LWS) extension as defined in RFC1323 to increase TCP's windows size. However this can only be done if either the operating system or the application can be modified to explicitly make use of TCP's LWS extension during connection setup. This work proposes a novel TCP-SuperCharger (TCP-SC) to enable TCP to fully utilize the underlying network bandwidth without modification to the applications or the operating system. TCP-SC is implemented as a gateway along the path between the sender and the receiver. By estimating the receiver's processing capacity, TCP-SC allows the sender to transmit more data than the amount of receiver buffer available. As modern computers are very fast compared to network speed, this prevents the receiver's buffer limit from restricting the throughput achievable by TCP. Experimental results show that TCP-SC can enable existing TCP with default buffer size (64 KB) to achieve 98% link utilization over a satellite link such as the WINDS communications satellite with 1,000 ms RTT and 24 Mbps bandwidth.

Yiu-Bun Lee, Jack; Tak-Shing Yum, Peter; Wan, Wing-San

284

ISO Far-Infrared Spectroscopic Observations of Jupiter  

NASA Astrophysics Data System (ADS)

We present the far-infrared spectrum of Jupiter that was measured with the Short and Long Wavelength Spectrometers (SWS and LWS) aboard the Infrared Space Observatory (ISO). The region between 38 and 44 microns was observed in grating mode, where the SWS provides a spectral resolution of about 1300. For longer waves up to 197 microns the LWS-FP (Fabry-Perot) was used to achieve a resolution of several thousand. The observations were made between 23 and 26 May 1997 during ISO's revolutions 554, 556 and 557. The Jovian spectrum in the far-infrared is compared to an atmospheric radiative transfer model using expected values for the vertical profiles of the atmospheric constituents. Rotational transitions of ammonia and phosphine are responsible for the absorption features observed: Strong ammonia absorption manifolds are obvious against the background continuum slope, appearing at 39, 42, 46, 51, 56, 63, 72, 84, 100 and 125 microns in both the data and the model. Also PH3 features are present at the expected wavelengths of 113 and 141 microns in both the data and the model. This is the first time that most of these far-infrared features have been detected. The ISO observations are therefore of interest for the preparation of the planned submillimeter studies of the atmospheres of the Jovian planets with FIRST.

Burgdorf, M. J.; Encrenaz, Th.; Feuchtgruber, H.; Davis, G. R.; Fouchet, Th.; Gautier, D.; Lellouch, E.; Orton, G. S.; Sidher, S. D.

2001-07-01

285

O-bearing Molecules in Carbon-rich Proto-Planetary Objects: Study of CRL 618  

NASA Astrophysics Data System (ADS)

We present ISO LWS observations of the proto-planetary nebula CRL 618, AFGL 618 a star evolving very fast to the planetary nebula stage. In addition to the lines of COd, COt, HCN and HNC, we report on the detection of water and OH emission together with the fine structure lines of [OI] at 63 and 145 microns. We suggest that O-bearing species other than CO are produced in the innermost region of the circumstellar envelope. The UV photons from the central star photodissociate most of the molecular species produced in the AGB phase and allow a chemistry dominated by standard ion-neutral reactions. Not only allow these reactions the formation of O-bearing species, but they also modify the abundances of C-rich molecules like HCN and HNC for which we found an abundance ratio of ? 1, much lower than in AGB stars. The molecular abundances in the different regions of the circumstellar envelope have been derived from radiative transfer models and our knowledge of its physical structure. Furthermore, we compare ISO LWS observations of three C-rich objects typical of each step of the fast transition of an AGB star to the Planetay Nebula stage: CRL 2688, AFGL 2688 a very young Proto-Planetary Nebula, CRL 618 a Proto-Planetary Nebula, and NGC 7027 a young Planetary Nebula.

Herpin, F.; Cernicharo, J.

2001-08-01

286

Evolution of the stimulated Raman scattering instability in two-dimensional particle-in-cell simulations  

SciTech Connect

In the following work, we analyze one-dimensional (1D) and two-dimensional (2D) full particle-in-cell simulations of stimulated Raman scattering (SRS) and study the evolution of Langmuir waves (LWs) in the kinetic regime. It is found that SRS reflectivity becomes random due to a nonlinear frequency shift and that the transverse modulations of LWs are induced by (i) the Weibel instability due to the current of trapped particles and (ii) the trapped particle modulational instability (TPMI) [H. Rose, Phys. Plasmas 12, 12318 (2005)]. Comparisons between 1D and 2D cases indicate that the nonlinear frequency shift is responsible for the first saturation of SRS. After this transient interval of first saturation, 2D effects become important: a strong side-scattering of the light, caused by these transverse modulations of the LW and the presence of a nonlinear frequency shift, is observed together with a strong transverse diffusion. This leads to an increase of the Landau damping rate of the LW, contributing to the limiting of Raman backscattering. A model is developed that reproduces the transverse evolution of the magnetic field due to trapped particles. Based on a simple 1D hydrodynamic model, the growth rate for the Weibel instability of the transverse electrostatic mode and magnetic field is estimated and found to be close to the TPMI growth rate [H. Rose et al., Phys. Plasmas 15, 042311 (2008)].

Masson-Laborde, P. E.; Casanova, M.; Loiseau, P. [CEA, DAM, DIF, F-91297 Arpajon (France); Rozmus, W.; Peng, Z. [Department of Physics, Theoretical Physics Institute, University of Alberta, Edmonton, Alberta T6G 2G7 (Canada); Pesme, D.; Hueller, S.; Chapman, T. [Centre de Physique Theorique, CNRS, Ecole Polytechnique, 91128 Palaiseau Cedex (France); Bychenkov, V. Yu. [P. N. Lebedev Physics Institute, Russian Academy of Science, Leninskii pr. 53, 11991 Moscow (Russian Federation)

2010-09-15

287

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.

288

Modelling and Prediction of Sensitivity in Energetic Materials  

Microsoft Academic Search

The search for new explosives needs predictive calculations of sensitivity. This is a complex problem as there are various definitions of this term : the drop weight impact test is often used to characterize sensitivity, but calculations are also related to shock waves sensitivity tests. Moreover, there are many parameters which influence the results, at molecular, mesoscopic and macroscopic levels.

D. Mathieu; P. Simonetti; R. Belmas; N. Garmasheva; V. Filin; A. Averin

2001-01-01

289

Deep-earth diffracted-wave tomography: A multiple-frequency high-resolution approach  

Microsoft Academic Search

We present a method to address the seismic forward and inverse problem at the global scale, with a specific focus on waves diffracted in the lowermost mantle. This spectral-element approach is developed in spherically symmetric background models, offering full-wave sensitivity up to 1 Hz. In order to get a direct view of the interconnection between surface displacements and earth structure,

T. Nissen-Meyer; A. Fournier; K. Sigloch

2008-01-01

290

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

291

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

2013-03-12

292

Infra-red rubidium atomic resonant filters for low wavenumber scattering  

NASA Astrophysics Data System (ADS)

This dissertation presents new approaches for low wavenumber scattering (LWS) based on infra-red rubidium filters, including blocking filters, dispersion filters, and passband filters. LWS is scattering of light with a small frequency change, such as rotational Raman scattering and Thomson scattering, which enables the measurement of species specific properties. The rubidium filters are used in conjunction with a tunable, pulsed Ti:sapphire laser to suppress background scattering and to achieve high resolution at low wavenumbers. The blocking filter is demonstrated to capture backward Thomson scattering as a single-ended diagnostic tool. The density gradient dispersion filter represents a new approach which is very promising for high dispersion, high collection efficiency Raman measurements. The passband filter extends recent work for high resolution Raman spectroscopy in the ultra-violet into the infra- red. The Ti:sapphire laser employs a grazing incidence cavity and a quadruple amplifier. It produces 10 nsec, 40 mJ/ pulse, 5~10 GHz linewidth, tunable output around 780 nm with less than 10-5 of amplified spontaneous emission. Wavelength calibration is achieved by newly obtained one and two photon optogalvanic spectroscopy of argon and neon. The first diagnostic approach uses a rubidium notch blocking filter to suppress elastic scattering from the laser. The filter application is demonstrated by capturing LWS from oxygen gas and solid sulfur, and backward Thomson scattering from an argon plasma in the infra-red region. Electron temperature and electron density in the plasma have been obtained by fitting to a theoretical model. The second approach introduces a new density gradient dispersion filter, designed for simultaneously rejecting the stray light and capturing multiple rotational Raman lines. This filter, which is based on the variation of refractive index near resonance, has a higher dispersion power than gratings at low wavenumbers. Pure rotational Raman scattering from CO2 gas has been obtained by this filter. The third approach uses an infrared passband filter based on resonant fluorescence of Rb. It features an ultra- narrow passband (less than 0.5 cm-1) and high suppression for the out-of-band emission. This filter is applied in measurement of high resolution Raman spectroscopy of sulfur.

Tang, Zhen

2001-07-01

293

Functional and Anatomic Consequences of Subretinal Dosing in the Cynomolgus Macaque  

PubMed Central

Objectives To characterize functional and anatomic sequelae of a bleb induced by subretinal injection. Methods Subretinal injections (100 ?l) of balance salt solution (BSS) were placed in the superotemporal macula of one eye in 3 cynomolgus macaques. Fellow eyes received intravitreal injections (100 ?l) of BSS. Fundus photography, ocular coherence tomography (OCT) and multifocal electroretinography (mfERG) were obtained before and immediately after injection and again at intervals up to 3 months post injection. Histopathologic analyses included transmission electron microscopy (TEM) and immunohistochemistry (IHC) for glial fibrillary acidic protein (GFAP), rhodopsin, M/L-cone opsin and S-cone opsin. Results Retinas were re-attached by 2 days post-injection (by OCT). mfERG was suppressed post-subretinal injection within the subretinal injection bleb and surprisingly, also in regions far peripheral to this region. mfERG amplitudes were nearly completely recovered by 90 days. The spectral domain (SD)-OCT inner segment/outer segment (IS/OS) line had decreased reflectivity at 92 days. GFAP and S-cone staining were unaffected. Rhodopsin and M/L-cone opsins were partially displaced into the inner segments. TEM revealed disorganization of the outer segment rod (but not cone) disks. At all post-injection intervals, eyes with intravitreal injection were similar to baseline. Conclusions Subretinal injection is a promising route for drug delivery to the eye. Three months post subretinal injection, retinal function was nearly recovered, although reorganization of the outer segment rod disk remained disrupted. Understanding the functional and anatomic effects of subretinal injection per se is important for interpretation of the effects of compounds delivered to the subretinal space. Clinical relevance Subretinal injection is a new potential route for drug delivery to the eye. Separating drug effects from the procedural effects per se is critical.

Nork, T. Michael; Murphy, Christopher J.; Kim, Charlene B. Y.; Hoeve, James N. Ver; Rasmussen, Carol A.; Miller, Paul E.; Wabers, Hugh D.; Neider, Michael W.; Dubielzig, Richard R.; McCulloh, Ryan J.; Christian, Brian J.

2011-01-01

294

Sexual dimorphism of short-wavelength photoreceptors in the small white butterfly, Pieris rapae crucivora.  

PubMed

The eyes of the female small white butterfly, Pieris rapae crucivora, are furnished with three classes of short-wavelength photoreceptors, with sensitivity peaks in the ultraviolet (UV) (lambda(max) = 360 nm), violet (V) (lambda(max) = 425 nm), and blue (B) (lambda(max) = 453 nm) wavelength range. Analyzing the spectral origin of the photoreceptors, we isolated three novel mRNAs encoding opsins corresponding to short-wavelength-absorbing visual pigments. We localized the opsin mRNAs in the retinal tissue and found that each of the short-wavelength-sensitive photoreceptor classes exclusively expresses one of the opsin mRNAs. We, accordingly, termed the visual pigments PrUV, PrV, and PrB, respectively. The eyes of the male small white butterfly also use three classes of short-wavelength photoreceptors that equally uniquely express PrUV, PrV, and PrB. However, whereas the spectral sensitivities of the male photoreceptors with PrUV and PrB closely correspond to those of the female, the male photoreceptor expressing PrV has a double-peaked blue (dB) spectral sensitivity, strongly deviating from the spectral sensitivity of the female V photoreceptor. The male eyes contain a pigment that distinctly fluoresces under blue-violet as well as UV excitation light. It coexists with the dB photoreceptors and presumably acts as a spectral filter with an absorbance spectrum peaking at 416 nm. The narrow-band spectral sensitivity of the male dB photoreceptors probably evolved to improve the discrimination of the different wing colors of male and female P. rapae crucivora in the short-wavelength region of the spectrum. PMID:15976082

Arikawa, Kentaro; Wakakuwa, Motohiro; Qiu, Xudong; Kurasawa, Masumi; Stavenga, Doekele G

2005-06-22

295

The phylogenetic distribution of ultraviolet sensitivity in birds  

PubMed Central

Background Colour vision in birds can be categorized into two classes, the ultraviolet (UVS) and violet sensitive (VS). Their phylogenetic distributions have traditionally been regarded as highly conserved. However, the complicated nature of acquiring spectral sensitivities from cone photoreceptors meant that until recently, only a few species had actually been studied. Whether birds are UVS or VS can nowadays be inferred from a wide range of species via genomic sequencing of the UV/violet SWS1 cone opsin gene. Results We present genomic sequencing results of the SWS1 gene from 21 avian orders. Amino acid residues signifying UV sensitivity are found in the two most important spectral tuning sites 86 and 90 of Pteroclidiformes and Coraciiformes, in addition to the major clades, Palaeognathae, Charadriiformes, Trogoniformes, Psittaciformes and Passeriformes, where they where previously known to occur. We confirm that the presumed UVS-conferring amino acid combination F86, C90 and M93 is common to Palaeognathae and unique to this clade, despite available spectrometric evidence showing the ostrich retina to be VS. Conclusions By mapping our results together with data from previous studies on a molecular phylogeny we show that avian colour vision shifted between VS and UVS at least 14 times. Single nucleotide substitutions can explain all these shifts. The common ancestor of birds most likely had a VS phenotype. However, the ancestral state of the avian SWS1 opsin’s spectral tuning sites cannot be resolved, since the Palaeognathae are F86, C90 while the Neognathae are ancestrally S86, S90. The phylogenetic distribution of UVS and VS colour vision in birds is so complex that inferences of spectral sensitivities from closely related taxa should be used with caution.

2013-01-01

296

Opn5 is a UV-sensitive bistable pigment that couples with Gi subtype of G protein.  

PubMed

Opn5 (neuropsin) belongs to an independent group separated from the other six groups in the phylogenetic tree of opsins, for which little information of absorption characteristics and molecular properties of the members is available. Here we show that the chicken Opn5 (cOpn5m) is a UV-sensitive bistable pigment that couples with Gi subtype of G protein. The recombinant expression of cOpn5m in HEK 293s cells followed by the addition of 11-cis- and all-trans-retinal produced UV light-absorbing and visible light-absorbing forms, respectively. These forms were interconvertible by UV and visible light irradiations, respectively, indicating that cOpn5m is a bistable pigment. The absorption maxima of these forms were estimated to be 360 and 474 nm, respectively. The GTP?S binding assay clearly showed that the visible light-absorbing form having all-trans-retinal activates Gi type of G protein, whereas no Gt or Gq activation ability was observed. Immunohistochemical studies using an antibody against cOpn5m clearly showed that this pigment is localized within some types of amacrine cells and some cells in the ganglion cell layer of the retinas, the vast majority of cells in the pineal gland and serotonin-positive cells in the paraventricular organ. Because cOpn5m is the only UV-sensitive opsin among the opsins found so far in chicken, this study provides the molecular basis for UV reception in chicken. PMID:21135214

Yamashita, Takahiro; Ohuchi, Hideyo; Tomonari, Sayuri; Ikeda, Keiko; Sakai, Kazumi; Shichida, Yoshinori

2010-12-06

297

Stable transgenesis in the marine annelid Platynereis dumerilii sheds new light on photoreceptor evolution.  

PubMed

Research in eye evolution has mostly focused on eyes residing in the head. In contrast, noncephalic light sensors are far less understood and rather regarded as evolutionary innovations. We established stable transgenesis in the annelid Platynereis, a reference species for evolutionary and developmental comparisons. EGFP controlled by cis-regulatory elements of r-opsin, a characteristic marker for rhabdomeric photoreceptors, faithfully recapitulates known r-opsin expression in the adult eyes, and marks a pair of pigment-associated frontolateral eyelets in the brain. Unexpectedly, transgenic animals revealed an additional series of photoreceptors in the ventral nerve cord as well as photoreceptors that are located in each pair of the segmental dorsal appendages (notopodia) and project into the ventral nerve cord. Consistent with a photosensory function of these noncephalic cells, decapitated animals display a clear photoavoidance response. Molecular analysis of the receptors suggests that they differentiate independent of pax6, a gene involved in early eye development of many metazoans, and that the ventral cells may share origins with the Hesse organs in the amphioxus neural tube. Finally, expression analysis of opn4×-2 and opn4m-2, two zebrafish orthologs of Platynereis r-opsin, reveals that these genes share expression in the neuromasts, known mechanoreceptors of the lateral line peripheral nervous system. Together, this establishes that noncephalic photoreceptors are more widespread than assumed, and may even reflect more ancient aspects of sensory systems. Our study marks significant advance for the understanding of photoreceptor cell (PRC) evolution and development and for Platynereis as a functional lophotrochozoan model system. PMID:23284166

Backfisch, Benjamin; Veedin Rajan, Vinoth Babu; Fischer, Ruth M; Lohs, Claudia; Arboleda, Enrique; Tessmar-Raible, Kristin; Raible, Florian

2013-01-02

298

Homologs of vertebrate Opn3 potentially serve as a light sensor in nonphotoreceptive tissue.  

PubMed

Most opsins selectively bind 11-cis retinal as a chromophore to form a photosensitive pigment, which underlies various physiological functions, such as vision and circadian photoentrainment. Recently, opsin 3 (Opn3), originally called encephalopsin or panopsin, and its homologs were identified in various tissues including brain, eye, and liver in both vertebrates and invertebrates, including human. Because Opn3s are mainly expressed in tissues that are not considered to contain sufficient amounts of 11-cis retinal to form pigments, the photopigment formation ability of Opn3 has been of interest. Here, we report the successful expression of Opn3 homologs, pufferfish teleost multiple tissue opsin (PufTMT) and mosquito Opn3 (MosOpn3) and show that these proteins formed functional photopigments with 11-cis and 9-cis retinals. The PufTMT- and MosOpn3-based pigments have absorption maxima in the blue-to-green region and exhibit a bistable nature. These Opn3 homolog-based pigments activate Gi-type and Go-type G proteins light dependently, indicating that they potentially serve as light-sensitive Gi/Go-coupled receptors. We also demonstrated that mammalian cultured cells transfected with the MosOpn3 or PufTMT became light sensitive without the addition of 11-cis retinal and the photosensitivity retained after the continuous light exposure, showing a reusable pigment formation with retinal endogenously contained in culture medium. Interestingly, we found that the MosOpn3 also acts as a light sensor when constituted with 13-cis retinal, a ubiquitously present retinal isomer. Our findings suggest that homologs of vertebrate Opn3 might function as photoreceptors in various tissues; furthermore, these Opn3s, particularly the mosquito homolog, could provide a promising optogenetic tool for regulating cAMP-related G protein-coupled receptor signalings. PMID:23479626

Koyanagi, Mitsumasa; Takada, Eiichiro; Nagata, Takashi; Tsukamoto, Hisao; Terakita, Akihisa

2013-03-11

299

Homologs of vertebrate Opn3 potentially serve as a light sensor in nonphotoreceptive tissue  

PubMed Central

Most opsins selectively bind 11-cis retinal as a chromophore to form a photosensitive pigment, which underlies various physiological functions, such as vision and circadian photoentrainment. Recently, opsin 3 (Opn3), originally called encephalopsin or panopsin, and its homologs were identified in various tissues including brain, eye, and liver in both vertebrates and invertebrates, including human. Because Opn3s are mainly expressed in tissues that are not considered to contain sufficient amounts of 11-cis retinal to form pigments, the photopigment formation ability of Opn3 has been of interest. Here, we report the successful expression of Opn3 homologs, pufferfish teleost multiple tissue opsin (PufTMT) and mosquito Opn3 (MosOpn3) and show that these proteins formed functional photopigments with 11-cis and 9-cis retinals. The PufTMT- and MosOpn3-based pigments have absorption maxima in the blue-to-green region and exhibit a bistable nature. These Opn3 homolog-based pigments activate Gi-type and Go-type G proteins light dependently, indicating that they potentially serve as light-sensitive Gi/Go-coupled receptors. We also demonstrated that mammalian cultured cells transfected with the MosOpn3 or PufTMT became light sensitive without the addition of 11-cis retinal and the photosensitivity retained after the continuous light exposure, showing a reusable pigment formation with retinal endogenously contained in culture medium. Interestingly, we found that the MosOpn3 also acts as a light sensor when constituted with 13-cis retinal, a ubiquitously present retinal isomer. Our findings suggest that homologs of vertebrate Opn3 might function as photoreceptors in various tissues; furthermore, these Opn3s, particularly the mosquito homolog, could provide a promising optogenetic tool for regulating cAMP-related G protein-coupled receptor signalings.

Koyanagi, Mitsumasa; Takada, Eiichiro; Nagata, Takashi; Tsukamoto, Hisao; Terakita, Akihisa

2013-01-01

300

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.

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

2010-01-01

301

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

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

1995-01-01

302

Single-copy nuclear genes recover cretaceous-age divergences in bees.  

PubMed

We analyzed the higher level phylogeny of the bee family Halictidae based on the coding regions of three single-copy nuclear genes (long-wavelength [LW] opsin, wingless, and elongation factor 1-alpha [EF-1 alpha]). Our combined data set consisted of 2,234 aligned nucleotide sites (702 base pairs [bp] for LW opsin, 405 bp for wingless, and 1,127 bp for EF-1 alpha) and 779 parsimony-informative sites. We included 58 species of halictid bees from 33 genera, representing all subfamilies and tribes, and rooted the trees using seven outgroups from other bee families: Colletidae, Andrenidae, Melittidae, and Apidae. We analyzed the separate and combined data sets by a variety of methods, including equal weights parsimony, maximum likelihood, and Bayesian methods. Analysis of the combined data set produced a strong phylogenetic signal with high bootstrap and Bremer support and high posterior probability well into the base of the tree. The phylogeny recovered the monophyly of the Halictidae and of all four subfamilies and both tribes, recovered relationships among the subfamilies and tribes congruent with morphology, and provided robust support for the relationships among the numerous genera in the tribe Halictini, sensu Michener (2000). Using our combined nucleotide data set, several recently described halictid fossils from the Oligocene and Eocene, and recently developed Bayesian methods, we estimated the antiquity of major clades within the family. Our results indicate that each of the four subfamilies arose well before the Cretaceous-Tertiary boundary and suggest that the early radiation of halictid bees involved substantial African-South American interchange roughly coincident with the separation of these two continents in the late Cretaceous. This combination of single-copy nuclear genes is capable of recovering Cretaceous-age divergences in bees with high levels of support. We propose that LW opsin, wingless, and EF-1 alpha(F2 copy) may be useful in resolving relationships among bee families and other Cretaceous-age insect lineages. PMID:15205055

Danforth, Bryan N; Brady, Seán G; Sipes, Sedonia D; Pearson, Adam

2004-04-01

303

Expression of the bop gene cluster of Halobacterium halobium is induced by low oxygen tension and by light.  

PubMed Central

The bop gene cluster consists of at least three genes: bop (bacterio-opsin), brp (bacterio-opsin-related protein), and bat (bacterio-opsin activator). We have quantitated transcript levels from these genes in a wild-type and bacterioruberin-deficient mutant of Halobacterium halobium under conditions which affect purple membrane synthesis. In wild-type cultures grown under high oxygen tension in the dark, bop and bat transcript levels were low during steady-state growth and then increased approximately 29- and approximately 45-fold, respectively, upon entry into stationary phase. brp gene transcription remained very low and essentially unchanged under these conditions. In addition, exposure of wild-type cultures growing under high oxygen tension to 30,000 lx of light stimulated expression of all three genes, especially brp. In contrast to the wild-type, transcription from all three genes in the bacterioruberin mutant was very high during steady-state growth under high oxygen tension in the dark. Cultures of the bacterioruberin mutant were shifted at early stationary phase to low oxygen tension to determine whether oxygen concentrations lower than those present in stationary phase would induce transcription of the bop gene cluster in this strain. Indeed, transcription was induced, suggesting that the bop gene cluster is not completely uncoupled from regulation by oxygen tension in the bacterioruberin mutant. From these data, we propose a regulatory model involving two different mechanisms: (i) bat gene expression is induced under conditions of low oxygen tension and the bat gene product activates bop gene expression and (ii) light induces brp transcription, which stimulates or modulates bat transcription.

Shand, R F; Betlach, M C

1991-01-01

304

New Isomers of Bovine Porphyropsin: A Nondestructive Method for Determining Chromophore Configuration during Formation of Visual Pigment Analogs  

Microsoft Academic Search

Binding interactions of six isomers (five previously unknown) of 3-dehydroretinal (3-DHR) with bovine opsin have been investigated. Of these only 7-cisand 7,9-di-cisisomers retained the original polyene configuration, giving the corresponding isomeric porphyropsin pigment analogs. The 7,13-di-cis, 7,9,11-tri-cis, and 7,9,13-tri-cisisomers of 3-DHR were found to lose readily the 13-cisor 11-cisgeometry, yielding instead the 7-cisor 7,9-di-cispigments. The 7,11-di-cisisomer yielded a pigment, believed

Rong-liang Chen; Robert S. H. Liu

1996-01-01

305

Energetics of primary processes in visula escitation: photocalorimetry of rhodopsin in rod outer segment membranes.  

PubMed

A sensitive technique for the direct calorimetric determination of the energetics of photochemical reactions under low levels of illumination, and its application to the study of primary processes in visula excitation, are described. Enthlpies are reported for various steps in the bleaching of rhodopsin in intact rod outer segment membranes, together with the heats of appropriate model reactions. Protonation changes are also determined calorimetrically by use of buffers with differing heats of proton ionization. Bleaching of rhodopsin is accompanied by significant uptake of heat energy, vastly in excess of the energy required for simple isomerization of the retinal chromophore. Metarhodopsin I formation involves the uptake of about 17 kcal/mol and no net change in proton ionization of the system. Formation of metarhodopsin II requires an additional energy of about 10 kcal/mol and involves the uptake on one hydrogen ion from solution. The energetics of the overall photolysis reaction, rhodopsin leads to opsin + all-trans-retinal, are pH dependent and involve the exposure of an additional titrating group on opsin. This group has a heat of proton ionization of about 12 kcal/mal, characteristic of a primary amine, but a pKa in the region of neutrality. We suggest that this group is the Schiff base lysine of the chromophore binding site of rhodopsin which becomes exposed on photolysis. The low pKa for this active lysine would result in a more stable retinal-opsin linkage, and might be induced by a nearby positively charged group on the protein (either arginine or a second lysine residue). This leads to a model involving intramolecular protonation of the Schiff base nitrogen in the retinal-opsin linkage of rhodopsin, which is consistent with the thermodynamic and spectroscopic properties of the system. We further propose that the metarhodopsin I leads to metarhodopsin II step in the bleaching sequence involves reversible hydrolysis of the Schiff base linkage in the chromophore binding site, and that subsequent steps are the result of migration of the chromophore from this site. PMID:8077

Cooper, A; Converse, C A

1976-07-13

306

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

307

Optobionic vision—a new genetically enhanced light on retinal prosthesis  

NASA Astrophysics Data System (ADS)

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 also show how this can be reduced down to safe levels in order to negate thermal and photochromic damage to the eye. We also describe a gallium nitride LED light source which is also able to generate patterns of the required intensity in order to transfer reliable images.

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

2009-06-01

308

Channelrhodopsin-1: a light-gated proton channel in green algae.  

PubMed

Phototaxis and photophobic responses of green algae are mediated by rhodopsins with microbial-type chromophores. We report a complementary DNA sequence in the green alga Chlamydomonas reinhardtii that encodes a microbial opsin-related protein, which we term Channelopsin-1. The hydrophobic core region of the protein shows homology to the light-activated proton pump bacteriorhodopsin. Expression of Channelopsin-1, or only the hydrophobic core, in Xenopus laevis oocytes in the presence of all-trans retinal produces a light-gated conductance that shows characteristics of a channel selectively permeable for protons. We suggest that Channelrhodopsins are involved in phototaxis of green algae. PMID:12089443

Nagel, Georg; Ollig, Doris; Fuhrmann, Markus; Kateriya, Suneel; Musti, Anna Maria; Bamberg, Ernst; Hegemann, Peter

2002-06-28

309

Compositional Constraints on the Atmospheres of Uranus and Neptune from Herschel and Spitzer Spectroscopic Observations  

NASA Astrophysics Data System (ADS)

Key elements of planetary compositions provide one of the most fundamental constraints on the origins and evolution of major bodies in the solar system. For the icy giants, Uranus and Neptune, acquiring compositional information has been a challenge because of their faintness. Great strides have been made with the advent of cryogenically cooled space-borne telescopes, however, and we report here the most recent of these results from Spitzer and Herschel telescopes, the latter including data taken within the framework of the Key Project "Water and Related Chemistry in the Solar system". Our interpretation of these results is set in the context of earlier results obtained by the ISO LWS and SWS spectrometers, together with relevant Earth-based observations. We will specifically discuss the chemical inventory and abundances stratospheric hydrocarbons, the implications of thermal structure for deep atmospheric composition, and improved constraints on the D/H ratio in Neptune.

Orton, G. S.; Moreno, R.; Lellouch, E.; Fletcher, L. N.; Hartogh, P.; Jarchow, C.; Feuchtgruber, H.; Line, M. R.; Herschel Key Project On Water; Related Chemistry in Solar System Team

2010-12-01

310

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

311

Magnetic Maps and Coronal/Solar Wind Modeling: Practices and Pitfalls (Invited)  

NASA Astrophysics Data System (ADS)

The ambient solar corona and solar wind play a crucial role in solar and heliospheric physics. The Sun's magnetic field is an essential ingredient of any predictive model of the solar wind. It defines the structure of the heliosphere, including the position of the heliospheric current sheet and the regions of fast and slow solar wind. The geoeffectiveness of CMEs is influenced in part by their interaction with the ambient magnetic field, and the field determines where SEPs propagate. To model the global magnetic field of the solar corona, maps of the magnetic field over the entire solar surface must be supplied as boundary conditions. In this talk, we demonstrate how common errors and uncertainties in the field measurements can at times strongly influence the solutions, and we discuss some of the key challenges to improving magnetic maps. Research supported by CISM (NSF), the LWS Strategic Capabilities Program (NASA, NSF, and AFOSR), and Heliophysics Theory Program (NASA).

Linker, J. A.; Mikic, Z.; Riley, P.; Lionello, R.; Titov, V. S.

2010-12-01

312

Behavior of 2D Turbulence Spectra at Long Wavelengths in Relation to Perpendicular Particle Transport  

NASA Astrophysics Data System (ADS)

Much past work on perpendicular particle transport in 2D magnetic turbulence has employed a model 2D spectrum with somewhat pathological characteristics such as an infinite correlation scale. Here we consider how the behavior of the spectrum at long wavelengths influences the perpendicular diffusion coefficient, by using spectrum models ranging from the somewhat pathological one commonly used in the past, to completely well behaved models consistent with strictly homogeneous turbulence. We also compare the predicted diffusion coefficients with key observational constraints, in the hope that the observations can provide insight into the correct form of the spectrum in the solar wind. Research supported in part by the NASA Heliophysics theory program NNX08AI47G, LWS program NNX07AH73G, and NSF SHINE ATM0752135.

Bieber, J. W.; Matthaeus, W. H.

2009-12-01

313

Minimum Energy Methods for Resolving the Azimuthal Ambiguity in Vector Magnetogram Data  

NASA Astrophysics Data System (ADS)

It has been demonstrated that minimum energy methods are the best available automated techniques to resolve the azimuthal ambiguity that is present in solar vector magnetogram data. The definition of the energy depends on the information available. One approach is based solely on the divergence-free property of magnetic fields. This definition is ideal because it makes no additional assumptions about the field, although it does require information about the line-of-sight variation of the field vector. When such information is not available other definitions must be employed. We will discuss and test methods that minimize a combination of the divergence and the current density, where the line-of-sight variation is derived from an extrapolation of the field from a single height. This work was supported by funding from NASA/LWS under contract NNH05CC75C.

Crouch, A. D.; Barnes, G.; Leka, K.

2008-05-01

314

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

315

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

316

Photoreceptor types, visual pigments, and topographic specializations in the retinas of hydrophiid sea snakes.  

PubMed

Sea snakes have evolved numerous anatomical, physiological, and behavioral adaptations to suit their wholly aquatic lifestyle. However, although sea snakes use vision for foraging and mate selection, little is known about their visual abilities. We used microspectrophotometry, light microscopy, and scanning electron microscopy to characterize the retinal photoreceptors of spine-bellied (Lapemis curtus) and horned (Acalyptophis peronii) sea snakes. Both species have three types of visual pigment sensitive to short (SWS; wavelength of maximum absorbance, ?max 428-430 nm), medium (MWS; ?max 496 nm), and long wavelengths of light (LWS; ?max 555-559 nm) in each of three different subtypes of cone-like single photoreceptor. They also possess a cone-like double photoreceptor subtype, both the principal and accessory member of which contain the LWS visual pigment. Conventional rods were not observed, although the MWS photoreceptor may be a "transmuted" rod. We also used stereology to measure the total number and topographic distribution of neurons in the ganglion cell layer of L. curtus, the olive sea snake (Aipysurus laevis), and the olive-headed sea snake (Disteira major). All species have a horizontal visual streak with specialized areas in the nasal and temporal retina. Both L. curtus and D. major also have a specialized area in the ventral retina, which may reflect differences in habitat usage and/or foraging behavior compared to A. laevis. Maximal spatial resolution was estimated at 1.1, 1.6, and 2.3 cycles deg?¹ in D. major, L. curtus, and A. laevis, respectively; the superior value for A. laevis may reflect its specialized crevice-foraging hunting technique. PMID:22020556

Hart, Nathan S; Coimbra, João Paulo; Collin, Shaun P; Westhoff, Guido

2012-04-15

317

The C/NOFS Satellite and its Relation to the Space Weather Objectives of NASA's Living With a Star Program  

NASA Astrophysics Data System (ADS)

A major objective of NASA's Living With a Star mission is to understand the variability of the plasma density in the earth's low and mid latitude ionosphere, including the conditions leading to the formation of equatorial spread-F irregularities and their location, magnitude, and spatial and temporal evolution. The main objectives of the Air Force Communication / Navigation Outage Forecasting System (C/NOFS) Mission of the Air Force Research Laboratory are to understand, model, and forecast the presence of equatorial ionospheric irregularities that adversely impact communication and navigation systems. Thus, the C/NOFS mission objectives are directly compatible with fundamental space weather goals of the LWS geospace program. The C/NOFS mission includes a satellite scheduled to be launched in September, 2005 into a low inclination (13°) elliptical (~375 x 710 km) orbit, as well as extensive ground-based observations and theory and modeling activities. The first satellite solely dedicated to forecasting ionospheric irregularities and radio wave scintillations, C/NOFS is equipped with sensors that measure ambient and fluctuating electron densities; ion and electron temperatures; AC and DC electric fields; magnetic fields; neutral winds; ion drifts; optical lightning emissions; ionospheric scintillations; and the electron content along the lines of sight between C/NOFS, GPS satellites, and ground receiver sites. To our knowledge, the sensor suite on C/NOFS is richer than on any previously flown equatorial satellite. C/NOFS is a joint Air Force Research Lab (AFRL) and Space Test Program (STP) mission. The neutral wind meter and ion drift meter are provided as part of the UTD Coupled-Ionosphere-Neutral Dynamics Investigation (CINDI) package that is funded by NASA's Explorer Program. This talk presents an overview of the C/NOFS mission and discusses its relevance to the LWS Geospace I-T Storm Probe mission.

Pfaff, R.; de La Beaujardiere, O.; Hunton, D.; Retterer, J.; Groves, K.; Jeong, L.; Heelis, R.; Earle, G.; Straus, P.; Bernhardt, P.

2005-05-01

318

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

2012-04-13

319

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

320

Galaxies: The Long Wavelength View  

NASA Astrophysics Data System (ADS)

Far-infrared spectroscopy obtained with the ISO LWS has shown that there is strong variation (more than 2 orders of magnitude) in the [CII]/FIR ratios in galaxies extending from blue compact dwarfs, to normal and starburst galaxies, down to elliptical and ultraluminous galaxies (ULIGs). The variation in the relative [CII] 158 ?m line strength has been attributed to low metallicity in blue compact dwarfs, high /n for normal galaxies and ULIGs, soft radiation fields in ellipticals, and extinction or enhanced abundance of dust in ionized regions in ULIGs. Full ISO/LWS far-infrared (43 - 197 ?m) spectra of six nearby IR-bright galaxies reveal a dramatic progression of decreasing fine-structure line emission from ionized species to molecular (OH and H2O) absorption line dominated. The archetypical ULIG, Arp 220, lies at the absorption line dominated end of this sequence. For Arp 220, radiative transfer models indicate that it is optically thick in the FIR and that the water molecules observed in absorption are radiatively excited. If extinction plays a role in the sequence it appears from this analysis that the affected regions are heavily obscured even in the far-infrared, while the detected line emission is not more obscured in ULIGs than in starbursts. Linear correlation between polycyclic aromatic hydrocarbon (PAH) 6.2 ?m feature strength and the [CII] 158 ?m line strength in starbursts and ULIGs suggests a similar effect for these emitting species, and that the detected PAH emission is not more obscured in ULIGs than in lower luminosity starbursts.

Fischer, J.

2000-11-01

321

Sequence divergence, polymorphism and evolution of the middle-wave and long-wave visual pigment genes of great apes and Old World monkeys.  

PubMed

In man, the spectral shift between the middle-wave (MW) and long-wave (LW) visual pigments is largely achieved by amino acid substitution at two codons, both located in exon 5. A third amino acid site coded by exon 3 is polymorphic between pigments. We have studied the equivalent regions of the cone opsin genes in two members of the Hominidea (the gorilla, Gorilla gorilla and the chimpanzee, Pan troglodytes) and in three members of the Cercopithecoidea family of Old World primates (the diana monkey, Cercopithecus diana, the talapoin monkey, Miopithecus talapoin, and the crab-eating macaque, Macaca fascicularis). No variation in the codons that specify the amino acids involved in spectral tuning were found. We predict therefore that the MW and LW pigments of gorilla and chimpanzee have similar spectral characteristics to those of man. Multiple copies of the same opsin gene sequence were identified in the chimpanzee, talapoin and macaque and we also show that non-human Old World primates are similar to man in showing a bunching of polymorphic sites in exon 3. We discuss the ancestry of the separate MW and LW genes of Old World primates and the equivalent polymorphic gene of the marmoset, a New World primate. PMID:7975287

Dulai, K S; Bowmaker, J K; Mollon, J D; Hunt, D M

1994-10-01

322

Optically triggering spatiotemporally confined GPCR activity in a cell and programming neurite initiation and extension.  

PubMed

G-protein-coupled receptor (GPCR) activity gradients evoke important cell behavior but there is a dearth of methods to induce such asymmetric signaling in a cell. Here we achieved reversible, rapidly switchable patterns of spatiotemporally restricted GPCR activity in a single cell. We recruited properties of nonrhodopsin opsins--rapid deactivation, distinct spectral tuning, and resistance to bleaching--to activate native Gi, Gq, or Gs signaling in selected regions of a cell. Optical inputs were designed to spatiotemporally control levels of second messengers, IP3, phosphatidylinositol (3,4,5)-triphosphate, and cAMP in a cell. Spectrally selective imaging was accomplished to simultaneously monitor optically evoked molecular and cellular response dynamics. We show that localized optical activation of an opsin-based trigger can induce neurite initiation, phosphatidylinositol (3,4,5)-triphosphate increase, and actin remodeling. Serial optical inputs to neurite tips can refashion early neuron differentiation. Methods here can be widely applied to program GPCR-mediated cell behaviors. PMID:23479634

Karunarathne, W K Ajith; Giri, Lopamudra; Kalyanaraman, Vani; Gautam, N

2013-03-11

323

Evolution of ultraviolet vision in shorebirds (Charadriiformes)  

PubMed Central

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.

Odeen, Anders; Hastad, Olle; Alstrom, Per

2010-01-01

324

Candidate genes for colour and vision exhibit signals of selection across the pied flycatcher (Ficedula hypoleuca) breeding range.  

PubMed

The role of natural selection in shaping adaptive trait differentiation in natural populations has long been recognized. Determining its molecular basis, however, remains a challenge. Here, we search for signals of selection in candidate genes for colour and its perception in a passerine bird. Pied flycatcher plumage varies geographically in both its structural and pigment-based properties. Both characteristics appear to be shaped by selection. A single-locus outlier test revealed 2 of 14 loci to show significantly elevated signals of divergence. The first of these, the follistatin gene, is expressed in the developing feather bud and is found in pathways with genes that determine the structure of feathers and may thus be important in generating variation in structural colouration. The second is a gene potentially underlying the ability to detect this variation: SWS1 opsin. These two loci were most differentiated in two Spanish pied flycatcher populations, which are also among the populations that have the highest UV reflectance. The follistatin and SWS1 opsin genes thus provide strong candidates for future investigations on the molecular basis of adaptively significant traits and their co-evolution. PMID:22027894

Lehtonen, P K; Laaksonen, T; Artemyev, A V; Belskii, E; Berg, P R; Both, C; Buggiotti, L; Bureš, S; Burgess, M D; Bushuev, A V; Krams, I; Moreno, J; Mägi, M; Nord, A; Potti, J; Ravussin, P-A; Sirkiä, P M; Sætre, G-P; Winkel, W; Primmer, C R

2011-10-26

325

DIVERSE TYPES OF GANGLION CELL PHOTORECEPTORS IN THE MAMMALIAN RETINA  

PubMed Central

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.

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

2012-01-01

326

Immunocytochemical demonstration of interphotoreceptor retinoid-binding protein in cerebellar medulloblastoma.  

PubMed

Previously, immunoreactive rod-opsin and S-antigen (arrestin), two highly characteristic markers of retinal photoreceptors and pinealocytes, were shown to be present in certain medulloblastoma cells. It, thus, has been suggested that such cells differentiate along the photoreceptor lineage. This is corroborated in the present immunocytochemical investigation using antibodies against another photoreceptor-cell marker, the interphotoreceptor retinoid-binding protein (IRBP). As shown in preparations of human retina and pineal organ, IRBP can be successfully demonstrated in formalin-fixed and paraffin-embedded tissue: the IRBP immunoreaction is located to the outer and inner segments of retinal photoreceptor cells and to perikarya of certain pinealocytes. Examination of formalin-fixed, paraffin-embedded biopsy specimens of 66 cerebellar medullo-blastomas revealed varying numbers of IRBP-immuno-reactive tumor cells in 19 cases that were formerly shown to contain rod-opsin and S-antigen immunoreaction. IRBP-immunoreactive tumor cells were also found in a retinoblastoma and a pineocytoma, but not in neuroblastoma, ganglioneuroblastoma, glioblastoma, oligodendroglioma and astrocytoma. The results indicate: (1) cerebellar medulloblastomas are heterogeneous in their differentiation potential; (2) one type of medulloblastoma displays photoreceptor characteristics; (3) this type appears to be closely related to retinoblastoma and pineal cell tumors; and (4) all three types of tumors may display additional common features to be explored in future studies. PMID:1377856

Korf, H W; Korf, B; Schachenmayr, W; Chader, G J; Wiggert, B

1992-01-01

327

Optically triggering spatiotemporally confined GPCR activity in a cell and programming neurite initiation and extension  

PubMed Central

G-protein–coupled receptor (GPCR) activity gradients evoke important cell behavior but there is a dearth of methods to induce such asymmetric signaling in a cell. Here we achieved reversible, rapidly switchable patterns of spatiotemporally restricted GPCR activity in a single cell. We recruited properties of nonrhodopsin opsins—rapid deactivation, distinct spectral tuning, and resistance to bleaching—to activate native Gi, Gq, or Gs signaling in selected regions of a cell. Optical inputs were designed to spatiotemporally control levels of second messengers, IP3, phosphatidylinositol (3,4,5)-triphosphate, and cAMP in a cell. Spectrally selective imaging was accomplished to simultaneously monitor optically evoked molecular and cellular response dynamics. We show that localized optical activation of an opsin-based trigger can induce neurite initiation, phosphatidylinositol (3,4,5)-triphosphate increase, and actin remodeling. Serial optical inputs to neurite tips can refashion early neuron differentiation. Methods here can be widely applied to program GPCR-mediated cell behaviors.

Karunarathne, W. K. Ajith; Giri, Lopamudra; Kalyanaraman, Vani; Gautam, N.

2013-01-01

328

Development of transgenic animals for optogenetic manipulation of mammalian nervous system function: Progress and prospects for behavioral neuroscience.  

PubMed

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

2013-03-06

329

Preservation of cone photoreceptors after a rapid yet transient degeneration and remodeling in cone-only Nrl?/? mouse retina  

PubMed Central

Cone photoreceptors are the primary initiator of visual transduction in the human retina. Dysfunction or death of rod photoreceptors precedes cone loss in many retinal and macular degenerative diseases, suggesting a rod-dependent trophic support for cone survival. Rod differentiation and homeostasis are dependent on the basic motif leucine zipper transcription factor NRL. The loss of Nrl (Nrl?/?) in mice results in a retina with predominantly S-opsin containing cones that exhibit molecular and functional characteristics of WT cones. Here we report that Nrl?/? retina undergoes a rapid but transient period of degeneration in early adulthood, with cone apoptosis, retinal detachment, alterations in retinal vessel structure, and activation and translocation of retinal microglia. However, cone degeneration stabilizes by four months of age, resulting in a thinner but intact outer nuclear layer with residual cones expressing S- and M-opsins and a preserved photopic ERG. At this stage, microglia translocate back to the inner retina and reacquire a quiescent morphology. Gene profiling analysis during the period of transient degeneration reveals misregulation of genes related to stress response and inflammation, implying their involvement in cone death. The Nrl?/? mouse illustrates the long-term viability of cones in the absence of rods and RPE defects in a rodless retina. We propose that Nrl?/? retina may serve as a model for elucidating mechanisms of cone homeostasis and degeneration that would be relevant to understanding diseases of the cone-dominant human macula.

Roger, Jerome E; Ranganath, Keerthi; Zhao, Lian; Cojocaru, Radu I; Brooks, Matthew; Gotoh, Norimoto; Veleri, Shobi; Hiriyanna, Avinash; Rachel, Rivka A; Campos, Maria Mercedes; Fariss, Robert N; Wong, Wai T; Swaroop, Anand

2012-01-01

330

Human melanopsin forms a pigment maximally sensitive to blue light (?max ? 479 nm) supporting activation of Gq/11 and Gi/o signalling cascades  

PubMed Central

A subset of mammalian retinal ganglion cells expresses an opsin photopigment (melanopsin, Opn4) and is intrinsically photosensitive. The human retina contains melanopsin, but the literature lacks a direct investigation of its spectral sensitivity or G-protein selectivity. Here, we address this deficit by studying physiological responses driven by human melanopsin under heterologous expression in HEK293 cells. Luminescent reporters for common second messenger systems revealed that light induces a high amplitude increase in intracellular calcium and a modest reduction in cAMP in cells expressing human melanopsin, implying that this pigment is able to drive responses via both Gq and Gi/o class G-proteins. Melanopsins from mouse and amphioxus had a similar profile of G-protein coupling in HEK293 cells, but chicken Opn4m and Opn4x pigments exhibited some Gs activity in addition to a strong Gq/11 response. An action spectrum for the calcium response in cells expressing human melanopsin had the predicted form for an opsin : vitamin A1 pigment and peaked at 479 nm. The G-protein selectivity and spectral sensitivity of human melanopsin is similar to that previously described for rodents, supporting the utility of such laboratory animals for developing methods of manipulating this system using light or pharmacological agents.

Bailes, Helena J.; Lucas, Robert J.

2013-01-01

331

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

332

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.

1982-01-01

333

Physiological characterization of the compound eye in monarch butterflies with focus on the dorsal rim area.  

PubMed

The spectral, angular and polarization sensitivities of photoreceptors in the compound eye of the monarch butterfly (Danaus plexippus) are examined using electrophysiological methods. Intracellular recordings reveal a spectrally homogenous population of UV receptors with optical axes directed upwards and >or=10 degrees to the contralateral side. Based on optical considerations and on the opsin expression pattern (Sauman et al. 2005), we conclude that these UV receptors belong to the anatomically specialized dorsal rim area (DRA) of the eye. Photoreceptors in the main retina with optical axes <10 degrees contralateral or ipsilateral have maximal sensitivities in the UV (lambda(max)opsin expression patterns described in these eye regions. The data are discussed in the light of present knowledge about polarized skylight navigation in Lepidopterans. PMID:16317560

Stalleicken, Julia; Labhart, Thomas; Mouritsen, Henrik

2005-11-30

334

Acute exposure to DE-71 causes alterations in visual behavior in zebrafish larvae.  

PubMed

Polybrominated diphenyl ethers (PBDEs) cause neurobehavioral toxicity, but their effects on visual behavior remain unknown. In the present study, the impact of PBDEs on visual behavior was examined using optokinetic responses and phototaxis in zebrafish larvae. Zebrafish embryos were exposed to pentabrominated diphenyl ethers mixture (DE-71) at concentrations of 0, 0.32, 3.58, and 31.0?µg/L until 15 d postfertilization. The authors then assessed photoreceptor opsin expression, retinal histology, and visual behavior of the larvae. The results showed that the transcriptions of the opsin genes, zfrho and zfgr1, were significantly upregulated. Western blotting further demonstrated a significant increase in rhodopsin protein expression after exposure of the larvae to DE-71. Histological examination revealed the following morphological alterations in the retina: increased area of inner nuclear layer, decreased area of inner plexiform layer, and decreased density of ganglion cells. Tests of optokinetic and phototactic behavior showed hyperactive responses on exposure to DE-71, including increased saccadic eye movements and phototactic response. The present study is the first to demonstrate that the acute exposure of zebrafish larvae to DE-71 causes biochemical and structural changes in the eye that lead to behavioral alterations. Analysis of these visual behavioral paradigms may be useful in predicting the adverse effects of toxicants on visual function in fish. PMID:23400899

Chen, Lianguo; Huang, Yubin; Huang, Changjiang; Hu, Bing; Hu, Chenyan; Zhou, Bingsheng

2013-06-01

335

Cone pigments in a North American marsupial, the opossum (Didelphis virginiana)  

PubMed Central

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.

Williams, Gary A.

2010-01-01

336

Heterologous expression of functional G-protein-coupled receptors in Caenorhabditis elegans  

PubMed Central

New strategies for expression, purification, functional characterization, and structural determination of membrane-spanning G-protein-coupled receptors (GPCRs) are constantly being developed because of their importance to human health. Here, we report a Caenorhabditis elegans heterologous expression system able to produce milligram amounts of functional native and engineered GPCRs. Both bovine opsin [(b)opsin] and human adenosine A2A subtype receptor [(h)A2AR] expressed in neurons or muscles of C. elegans were localized to cell membranes. Worms expressing these GPCRs manifested changes in motor behavior in response to light and ligands, respectively. With a newly devised protocol, 0.6–1 mg of purified homogenous 9-cis-retinal-bound bovine isorhodopsin [(b)isoRho] and ligand-bound (h)A2AR were obtained from C. elegans from one 10-L fermentation at low cost. Purified recombinant (b)isoRho exhibited its signature absorbance spectrum and activated its cognate G-protein transducin in vitro at a rate similar to native rhodopsin (Rho) obtained from bovine retina. Generally high expression levels of 11 native and mutant GPCRs demonstrated the potential of this C. elegans system to produce milligram quantities of high-quality GPCRs and possibly other membrane proteins suitable for detailed characterization.—Salom, D., Cao, P., Sun, W., Kramp, K., Jastrzebska, B., Jin, H., Feng, Z., Palczewski, K. Heterologous expression of functional G-protein-coupled receptors in Caenorhabditis elegans.

Salom, David; Cao, Pengxiu; Sun, Wenyu; Kramp, Kristopher; Jastrzebska, Beata; Jin, Hui; Feng, Zhaoyang; Palczewski, Krzysztof

2012-01-01

337

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

2012-03-26

338

The ciliopathy gene cc2d2a controls zebrafish photoreceptor outer segment development through a role in Rab8-dependent vesicle trafficking  

PubMed Central

Ciliopathies are a genetically and phenotypically heterogeneous group of human developmental disorders whose root cause is the absence or dysfunction of primary cilia. Joubert syndrome is characterized by a distinctive hindbrain malformation variably associated with retinal dystrophy and cystic kidney disease. Mutations in CC2D2A are found in ?10% of patients with Joubert syndrome. Here we describe the retinal phenotype of cc2d2a mutant zebrafish consisting of disorganized rod and cone photoreceptor outer segments resulting in abnormal visual function as measured by electroretinogram. Our analysis reveals trafficking defects in mutant photoreceptors affecting transmembrane outer segment proteins (opsins) and striking accumulation of vesicles, suggesting a role for Cc2d2a in vesicle trafficking and fusion. This is further supported by mislocalization of Rab8, a key regulator of opsin carrier vesicle trafficking, in cc2d2a mutant photoreceptors and by enhancement of the cc2d2a retinal and kidney phenotypes with partial knockdown of rab8. We demonstrate that Cc2d2a localizes to the connecting cilium in photoreceptors and to the transition zone in other ciliated cell types and that cilia are present in these cells in cc2d2a mutants, arguing against a primary function for Cc2d2a in ciliogenesis. Our data support a model where Cc2d2a, localized at the photoreceptor connecting cilium/transition zone, facilitates protein transport through a role in Rab8-dependent vesicle trafficking and fusion.

Bachmann-Gagescu, Ruxandra; Phelps, Ian G.; Stearns, George; Link, Brian A.; Brockerhoff, Susan E.; Moens, Cecilia B.; Doherty, Dan

2011-01-01

339

AHI1 is required for outer segment development and is a modifier for retinal degeneration in nephronophthisis  

PubMed Central

Photoreceptor degeneration is a common feature of ciliopathies, owing to the importance of the highly specialized ciliary structure of these cells. Absence of AHI1, which encodes a cilium-localized protein, has been shown to cause a form of Joubert syndrome highly penetrant for retinal degeneration1,2. We show that Ahi1 knockout mice fail to form outer segments (OS), and show abnormal distribution of opsin throughout photoreceptors. Apoptotic cell death occurs rapidly between 2-4 weeks of age and is significantly delayed by reduced dosage of opsin. This phenotype also displays dosage-sensitive genetic interactions with Nphp1, another ciliopathy gene. Although not a primary cause of retinal blindness in humans, an allele of AHI1 modifies the relative risk of retinal degeneration greater than 7 fold within a nephronophthisis cohort. Our data support context-specific roles for AHI1 as a contributor to retinopathy and may explain a proportion of the variability of retinal phenotypes observed in nephronophthisis.

Louie, Carrie M; Caridi, Gianluca; Lopes, Vanda S; Brancati, Francesco; Kispert, Andreas; Lancaster, Madeline A; Schlossman, Andrew M; Otto, Edgar A; Leitges, Michael; Groene, Hermann-Josef; Lopez, Irma; Gudiseva, Harini V; O'Toole, John F; Vallespin, Elena; Ayyagari, Radha; Ayuso, Carmen; Cremers, Frans P; den Hollander, Anneke I; Koenekoop, Robert K; Dallapiccola, Bruno; Ghiggeri, Gian Marco; Hildebrandt, Friedhelm; Valente, Enza Maria; Williams, David S; Gleeson, Joseph G

2010-01-01

340

The pineal complex of the European sea bass (Dicentrarchus labrax): I. histological, immunohistochemical and qPCR study.  

PubMed

The pineal organ of fish is a photosensory and neuroendocrine epithalamic structure that plays a key role in the temporal organisation of physiological and behavioural processes. In this study performed in the European sea bass, Dicentrarchus labrax, we provided an in-depth description of the macroscopic and microscopic anatomy of the pineal organ and identified the presence of photoreceptor and presumed melatonin-producing cells using histological and immunohistochemical techniques. In addition, we analysed in the pineal the day-night expression (using quantitative real-time PCR) of two key enzymes in the melatonin-synthesising pathway; arylalkylamine-N-acetyltransferase 2 (AANAT2) and hydroxyindole-O-methyltransferase (HIOMT). The pineal complex of sea bass consisted of a narrow and short pineal stalk that adopts a vertical disposition, a small-sized pineal end vesicle firmly attached to the skull by connective tissue, a parapineal organ and a convoluted dorsal sac. Immunohistochemical study showed the presence of abundant serotonin-positive cells. Cone opsin-like and rod opsin-like photoreceptor cells were also evidenced in the pineal stalk and vesicle. Both Aanat2 and Hiomt were expressed in sea bass pineal organ. Aanat2 exhibited higher nocturnal transcript levels, while no significant day-night differences were found for Hiomt. These results, together with ongoing studies analysing neural and neurohormonal outputs from the pineal organ of sea bass, provide the basic framework to understand the transduction integration of light stimulus in this relevant species for marine aquaculture. PMID:21310229

Herrera-Pérez, P; Servili, A; Rendón, M C; Sánchez-Vázquez, F J; Falcón, J; Muñoz-Cueto, J A

2011-02-16

341

Human melanopsin forms a pigment maximally sensitive to blue light (?max ? 479 nm) supporting activation of G(q/11) and G(i/o) signalling cascades.  

PubMed

A subset of mammalian retinal ganglion cells expresses an opsin photopigment (melanopsin, Opn4) and is intrinsically photosensitive. The human retina contains melanopsin, but the literature lacks a direct investigation of its spectral sensitivity or G-protein selectivity. Here, we address this deficit by studying physiological responses driven by human melanopsin under heterologous expression in HEK293 cells. Luminescent reporters for common second messenger systems revealed that light induces a high amplitude increase in intracellular calcium and a modest reduction in cAMP in cells expressing human melanopsin, implying that this pigment is able to drive responses via both Gq and Gi/o class G-proteins. Melanopsins from mouse and amphioxus had a similar profile of G-protein coupling in HEK293 cells, but chicken Opn4m and Opn4x pigments exhibited some Gs activity in addition to a strong Gq/11 response. An action spectrum for the calcium response in cells expressing human melanopsin had the predicted form for an opsin : vitamin A1 pigment and peaked at 479 nm. The G-protein selectivity and spectral sensitivity of human melanopsin is similar to that previously described for rodents, supporting the utility of such laboratory animals for developing methods of manipulating this system using light or pharmacological agents. PMID:23554393

Bailes, Helena J; Lucas, Robert J

2013-04-03

342

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

343

Evolution of vertebrate retinal photoreception  

PubMed Central

Recent findings shed light on the steps underlying the evolution of vertebrate photoreceptors and retina. Vertebrate ciliary photoreceptors are not as wholly distinct from invertebrate rhabdomeric photoreceptors as is sometimes thought. Recent information on the phylogenies of ciliary and rhabdomeric opsins has helped in constructing the likely routes followed during evolution. Clues to the factors that led the early vertebrate retina to become invaginated can be obtained by combining recent knowledge about the origin of the pathway for dark re-isomerization of retinoids with knowledge of the inability of ciliary opsins to undergo photoreversal, along with consideration of the constraints imposed under the very low light levels in the deep ocean. Investigation of the origin of cell classes in the vertebrate retina provides support for the notion that cones, rods and bipolar cells all originated from a primordial ciliary photoreceptor, whereas ganglion cells, amacrine cells and horizontal cells all originated from rhabdomeric photoreceptors. Knowledge of the molecular differences between cones and rods, together with knowledge of the scotopic signalling pathway, provides an understanding of the evolution of rods and of the rods' retinal circuitry. Accordingly, it has been possible to propose a plausible scenario for the sequence of evolutionary steps that led to the emergence of vertebrate photoreceptors and retina.

Lamb, Trevor D.

2009-01-01

344

pH-dependent interaction of rhodopsin with cyanidin-3-glucoside. 2. Functional aspects.  

PubMed

Anthocyanins are a class of phytochemicals that confer color to flowers, fruits, vegetables and leaves. They are part of our regular diet and serve as dietary supplements because of numerous health benefits, including improved vision. Recent studies have shown that the anthocyanin cyanidin-3-O-glucoside (C3G) increased regeneration of the dim-light photoreceptor rhodopsin (Matsumoto et al. [2003] J. Agric. Food Chem., 51, 3560-3563). In an accompanying study (Yanamala et al. [2009] Photochem. Photobiol.), we show that C3G directly binds to rhodopsin in a pH-dependent manner. In this study, we investigated the functional consequences of C3G binding to rhodopsin. As observed previously in rod outer segments, regeneration of purified rhodopsin in detergent micelles is also accelerated in the presence of C3G. Thermal denaturation and stability studies using circular dichroism, fluorescence and UV/visible absorbance spectroscopy show that C3G exerts a destabilizing effect on rhodopsin structure while it only modestly alters G-protein activation and the rates at which the light-activated Metarhodopsin II state decays to opsin and free retinal. These results indicate that the mechanism of C3G-enhanced regeneration may be based on changes in opsin structure promoting access to the retinal binding pocket. PMID:19267871

Tirupula, Kalyan C; Balem, Fernanda; Yanamala, Naveena; Klein-Seetharaman, Judith

345

The expression of genes encoding visual components is regulated by a circadian clock, light environment and age in the honeybee (Apis mellifera).  

PubMed

The honeybee, Apis mellifera, has been used as a model to study the development of the visual system and adult bee behaviour. However, the regulation of the levels of visual component genes has never been addressed in this organism. We isolated honeybee cDNAs encoding green-sensitive opsin and visual arrestin and then measured their mRNA levels in honeybee workers. Both mRNAs fluctuate on a daily cycle that depends on a pacemaker that functions separately from the pacemaker which controls rhythmic locomotor activity. The cycling-patterns of opsin and arrestin mRNAs are different from each other and are modified by light. Furthermore, light exposure can increase the absolute levels of both mRNAs and the arrestin mRNA level is also dependent on age. Consistent with these results, both mRNA levels are higher in foragers than in in-hive bees under natural conditions. This study thus shows that the expression of genes encoding visual components is regulated by multiple factors and is adjusted to the honeybees' need for vision during the day, and throughout their lives. Comparison of data obtained with honeybees and other organisms indicates that there is a link between the regulation of phototransduction components and vision-related animal behaviour. PMID:12653972

Sasagawa, Hiromi; Narita, Ryo; Kitagawa, Yasuo; Kadowaki, Tatsuhiko

2003-03-01

346

Retinal photoisomerase: role in invertebrate visual cells.  

PubMed

In invertebrate visual cells, the rhodopsin content is maintained at a high level by the fast process of photoregeneration during daylight. Rhodopsin is converted by photoabsorption to metarhodopsin, which is reconverted to rhodopsin by light. In addition, rhodopsin is regenerated by a slow process of renewal which takes days to complete and involves the biosynthesis of opsin. It is well known that rhodopsin can be formed from opsin only when 11-cis-retinal is present; this requires the existence of an isomerizing enzyme which is capable of transforming all-trans-retinal, released from the degradation of metarhodopsin, into the 11-cis-retinal isomer. In some invertebrate visual systems, experiments on rhodopsin regeneration have been interpreted by assuming that the isomerization reaction is a light-dependent process involving a retinal-protein complex. Two retinal photoisomerases which have been well characterized, i.e. bee photoisomerase and cephalopod retinochrome, are reviewed here. Their properties are compared in order to determine their physiological role, which is likely to be in the renewal of visual pigment rhodopsin. To conclude, a visual pigment cycle is proposed in which rhodopsin regeneration follows two light-dependent pathways. This greatly simplifies the rhodopsin regeneration scheme for invertebrate visual systems. PMID:1403367

Pepe, I M; Cugnoli, C

1992-04-15

347

Structural and Functional Effects of Hemiretinal Endodiathermy Axotomy in Cynomolgus Macaques  

PubMed Central

Purpose. Outer retinal injury has been well described in glaucoma. To better understand the source of this injury, we wanted to develop a reliable model of partial retinal ganglion cell (RGC) axotomy. Methods. Endodiathermy spots were placed along the inferior 180° adjacent to the optic nerve margin in the right eyes of four cynomolgus monkeys. Fluorescein angiography, spectral domain optical coherence tomography (SD-OCT), and multifocal electroretinography (mfERG) were performed at various intervals. Two animals were sacrificed at 3 months. Two animals were sacrificed at 4 months, at which time they underwent an injection of fluorescent microspheres to measure regional choroidal blood flow. Retinal immunohistochemistry for glial fibrillary acidic protein (GFAP), rhodopsin, S-cone opsin, and M/L-cone opsin were performed, as were axon counts of the optic nerves. Results. At 3 months, there was marked thinning of the inferior nerve fiber layer on SD-OCT. The mfERG waveforms were consistent with inner but not outer retinal injury. Greater than 95% reduction in axons was seen in the inferior optic nerves but no secondary degeneration superiorly. There was marked thinning of the nerve fiber and ganglion cell layers in the inferior retinas. However, the photoreceptor histology was similar in the axotomized and nonaxotomized areas. Regional choroidal blood flow was not affected by the axotomy. Conclusions. Unlike experimental glaucoma, hemiretinal endodiathermy axotomy (HEA) of the RGCs produces no apparent anatomic, functional, or blood flow effects on the outer retina and choroid.

Dashek, Ryan J.; Kim, Charlene B. Y.; Rasmussen, Carol A.; Hennes-Beean, Elizabeth A.; VerHoeve, James N.; Nork, T. Michael

2013-01-01

348

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.

Holland, Linda Z.; Albalat, Ricard; Azumi, Kaoru; Benito-Gutierrez, Elia; Blow, Matthew J.; Bronner-Fraser, Marianne; Brunet, Frederic; Butts, Thomas; Candiani, Simona; Dishaw, Larry J.; Ferrier, David E.K.; Garcia-Fernandez, Jordi; Gibson-Brown, Jeremy J.; Gissi, Carmela; Godzik, Adam; Hallbook, 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

349

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

2011-07-27

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.

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

2012-01-01

351

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

352

Optogenetic control of targeted peripheral axons in freely moving animals.  

PubMed

Optogenetic control of the peripheral nervous system (PNS) would enable novel studies of motor control, somatosensory transduction, and pain processing. Such control requires the development of methods to deliver opsins and light to targeted sub-populations of neurons within peripheral nerves. We report here methods to deliver opsins and light to targeted peripheral neurons and robust optogenetic modulation of motor neuron activity in freely moving, non-transgenic mammals. We show that intramuscular injection of adeno-associated virus serotype 6 enables expression of channelrhodopsin (ChR2) in motor neurons innervating the injected muscle. Illumination of nerves containing mixed populations of axons from these targeted neurons and from neurons innervating other muscles produces ChR2-mediated optogenetic activation restricted to the injected muscle. We demonstrate that an implanted optical nerve cuff is well-tolerated, delivers light to the sciatic nerve, and optically stimulates muscle in freely moving rats. These methods can be broadly applied to study PNS disorders and lay the groundwork for future therapeutic application of optogenetics. PMID:23991144

Towne, Chris; Montgomery, Kate L; Iyer, Shrivats M; Deisseroth, Karl; Delp, Scott L

2013-08-21

353

Structure-function studies on bacteriorhodopsin. IX. Substitutions of tryptophan residues affect protein-retinal interactions in bacteriorhodopsin  

SciTech Connect

Bacteriorhodopsin contains 8 tryptophan residues distributed across the membrane-embedded helices. To study their possible functions, we have replaced them one at a time by phenylalanine; in addition, Trp-137 and -138 have been replaced by cysteine. The mutants were prepared by cassette mutagenesis of the synthetic bacterio-opsin gene, expression and purification of the mutant apoproteins, renaturation, and chromophore regeneration. The replacement of Trp-10, Trp-12 (helix A), Trp-80 (helix C), and Trp-138 (helix E) by phenylalanine and of Trp-137 and Trp-138 by cysteine did not significantly alter the absorption spectra or affect their proton pumping. However, substitution of the remaining tryptophans by phenylalanine had the following effects. (1) Substitution of Trp-86 (helix C) and Trp-137 gave chromophores blue-shifted by 20 nm and resulted in reduced proton pumping to about 30%. (2) As also reported previously, substitution of Trp-182 and Trp-189 (helix F) caused large blue shifts (70 and 40 nm, respectively) in the chromophore and affected proton pumping. (3) The substitution of Trp-86 and Trp-182 by phenylalanine conferred acid instability on these mutants. The spectral shifts indicate that Trp-86, Trp-182, Trp-189, and possibly Trp-137 interact with retinal. It is proposed that these tryptophans, probably along with Tyr-57 (helix B) and Tyr-185 (helix F), form a retinal binding pocket. We discuss the role of tryptophan residues that are conserved in bacteriorhodopsin, halorhodopsin, and the related family of opsin proteins.

Mogi, T.; Marti, T.; Khorana, H.G. (Massachusetts Institute of Technology, Cambridge (USA))

1989-08-25

354

Heterologous gene expression in a membrane-protein-specific system.  

PubMed

We have constructed an expression system for heterologous proteins which uses the molecular machinery responsible for the high level production of bacteriorhodopsin in Halobacterium salinarum. Cloning vectors were assembled that fused sequences of the bacterio-opsin gene (bop) to coding sequences of heterologous genes and generated DNA fragments with cloning sites that permitted transfer of fused genes into H. salinarum expression vectors. Gene fusions include: (i) carboxyl-terminal-tagged bacterio-opsin; (ii) a carboxyl-terminal fusion with the catalytic subunit of the Escherichia coli aspartate transcarbamylase; (iii) the human muscarinic receptor, subtype M1; (iv) the human serotonin receptor, type 5HT2c; and (v) the yeast alpha mating factor receptor, Ste2. Characterization of the expression of these fusions revealed that the bop gene coding region contains previously undescribed molecular determinants which are critical for high level expression. For example, introduction of immunogenic and purification tag sequences into the C-terminal coding region significantly decreased bop gene mRNA and protein accumulation. The bacteriorhodopsin-aspartate transcarbamylase fusion protein was expressed at 7 mg per liter of culture, demonstrating that E. coli codon usage bias did not limit the system's potential for high level expression. The work presented describes initial efforts in the development of a novel heterologous protein expression system, which may have unique advantages for producing multiple milligram quantities of membrane-associated proteins. PMID:10545281

Turner, G J; Reusch, R; Winter-Vann, A M; Martinez, L; Betlach, M C

1999-11-01

355

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

356

Crystal structure of metarhodopsin II.  

PubMed

G-protein-coupled receptors (GPCRs) are seven transmembrane helix (TM) proteins that transduce signals into living cells by binding extracellular ligands and coupling to intracellular heterotrimeric G proteins (G???). The photoreceptor rhodopsin couples to transducin and bears its ligand 11-cis-retinal covalently bound via a protonated Schiff base to the opsin apoprotein. Absorption of a photon causes retinal cis/trans isomerization and generates the agonist all-trans-retinal in situ. After early photoproducts, the active G-protein-binding intermediate metarhodopsin II (Meta?II) is formed, in which the retinal Schiff base is still intact but deprotonated. Dissociation of the proton from the Schiff base breaks a major constraint in the protein and enables further activating steps, including an outward tilt of TM6 and formation of a large cytoplasmic crevice for uptake of the interacting C terminus of the G? subunit. Owing to Schiff base hydrolysis, Meta?II is short-lived and notoriously difficult to crystallize. We therefore soaked opsin crystals with all-trans-retinal to form Meta?II, presuming that the crystal's high concentration of opsin in an active conformation (Ops*) may facilitate all-trans-retinal uptake and Schiff base formation. Here we present the 3.0?Å and 2.85?Å crystal structures, respectively, of Meta?II alone or in complex with an 11-amino-acid C-terminal fragment derived from G? (G?CT2). G?CT2 binds in a large crevice at the cytoplasmic side, akin to the binding of a similar G?-derived peptide to Ops* (ref. 7). In the Meta?II structures, the electron density from the retinal ligand seamlessly continues into the Lys?296 side chain, reflecting proper formation of the Schiff base linkage. The retinal is in a relaxed conformation and almost undistorted compared with pure crystalline all-trans-retinal. By comparison with early photoproducts we propose how retinal translocation and rotation induce the gross conformational changes characteristic for Meta?II. The structures can now serve as models for the large GPCR family. PMID:21389988

Choe, Hui-Woog; Kim, Yong Ju; Park, Jung Hee; Morizumi, Takefumi; Pai, Emil F; Krauss, Norbert; Hofmann, Klaus Peter; Scheerer, Patrick; Ernst, Oliver P

2011-03-09

357

Preparation of living isolated vertebrate photoreceptor cells for fluorescence imaging.  

PubMed

In the vertebrate retina, phototransduction, the conversion of light to an electrical signal, is carried out by the rod and cone photoreceptor cells¹??. Rod photoreceptors are responsible for vision in dim light, cones in bright light. Phototransduction takes place in the outer segment of the photoreceptor cell, a specialized compartment that contains a high concentration of visual pigment, the primary light detector. The visual pigment is composed of a chromophore, 11-cis retinal, attached to a protein, opsin. A photon absorbed by the visual pigment isomerizes the chromophore from 11-cis to all-trans. This photoisomerization brings about a conformational change in the visual pigment that initiates a cascade of reactions culminating in a change in membrane potential, and bringing about the transduction of the light stimulus to an electrical signal. The recovery of the cell from light stimulation involves the deactivation of the intermediates activated by light, and the reestablishment of the membrane potential. Ca²+ modulates the activity of several of the enzymes involved in phototransduction, and its concentration is reduced upon light stimulation. In this way, Ca²+ plays an important role in the recovery of the cell from light stimulation and its adaptation to background light. Another essential part of the recovery process is the regeneration of the visual pigment that has been destroyed during light-detection by the photoisomerization of its 11-cis chromophore to all-trans???. This regeneration begins with the release of all-trans retinal by the photoactivated pigment, leaving behind the apo-protein opsin. The released all-trans retinal is rapidly reduced in a reaction utilizing NADPH to all- trans retinol, and opsin combines with fresh 11-cis retinal brought into the outer segment to reform the visual pigment. All-trans retinol is then transferred out of the outer segment and into neighboring cells by the specialized carrier Interphotoreceptor Retinoid Binding Protein (IRBP). Fluorescence imaging of single photoreceptor cells can be used to study their physiology and cell biology. Ca²+-sensitive fluorescent dyes can be used to examine in detail the interplay between outer segment Ca²+ changes and response to light??¹² as well as the role of inner segment Ca²+ stores in Ca²+ homeostasis¹³?¹?. Fluorescent dyes can also be used for measuring Mg² concentration¹?, pH, and as tracers of aqueous and membrane compartments¹?. Finally, the intrinsic fluorescence of all-trans retinol (vitamin A) can be used to monitor the kinetics of its formation and removal in single photoreceptor cells¹??¹?. PMID:21730941

Boyer, Nicholas P; Chen, Chunhe; Koutalos, Yiannis

2011-06-22

358

The ISO spectroscopic view of the HH 24-26 region  

NASA Astrophysics Data System (ADS)

We report the results of an investigation, performed with the ISO spectrometers (LWS and SWS), on the star forming region associated with the Herbig-Haro objects HH 24-25 and 26. Low-resolution LWS spectra (45-197 mu m) were observed towards the HH24MMS, HH25MMS and HH26IR sources as well as the HH26IR outflow. In addition, SWS scans of the pure H_2 rotational lines towards HH24MMS were acquired. Emission from [O I] 63 mu m,and [C Ii] 158 mu m,appears widespread while molecular transitions of carbon monoxide and water vapour were detected only towards HH25MMS and the blue lobe of HH26IR. From the analysis of the observed emission we deduce that the gas towards HH24MMS and HH25MMS is excited at densities ~ 106 cm-3 and temperatures ranging from 650 to 1400 K in HH24MMS and from 150 to 550 K in HH25MMS. Along the blue lobe of the HH26IR outflow, a more diffuse (n_H_2 ~ 104 cm-3) and warm (T ~ 1800 K) gas is found. Both the molecular (CO, H_2O,and H_2) and atomic ([O I]) emission in the three sources can be interpreted as due to shock excitation, and a mixture of both C- and J-type shocks are required to reproduce most of the observed characteristics of the spectra. The derived water abundances (3 10-7-9 10-6) are lower than expected in warm shock excited gas, a result which has also been found in other similar regions investigated with ISO. The total cooling derived from the gas component traced by the FIR lines is always of the same order or larger than the cooling due to the molecular hydrogen as traced by the H_2,2.12 mu m,line; although this latter could be underestimated if the dust extinction is not negligible, however it is evident that a significant fraction of the energy released in the shocks is re-radiated away by the far infrared lines. Finally, the [C Ii]158mu m,line intensities are rather constant at all of the observed positions, excluding the presence of strong photo-dissociation regions related to the nearby IR sources. Based on observations with ISO, an ESA project with instruments funded by ESA Member States and with the participation of ISAS and NASA

Benedettini, M.; Giannini, T.; Nisini, B.; Tommasi, E.; Lorenzetti, D.; Di Giorgio, A. M.; Saraceno, P.; Smith, H. A.; White, G. J.

2000-07-01

359

Visual ecology of the Australian lungfish (Neoceratodus forsteri)  

PubMed Central

Background The transition from water to land was a key event in the evolution of vertebrates that occurred over a period of 15–20 million years towards the end of the Devonian. Tetrapods, including all land-living vertebrates, are thought to have evolved from lobe-finned (sarcopterygian) fish that developed adaptations for an amphibious existence. However, while many of the biomechanical and physiological modifications necessary to achieve this feat have been studied in detail, little is known about the sensory adaptations accompanying this transition. In this study, we investigated the visual system and visual ecology of the Australian lungfish Neoceratodus forsteri, which is the most primitive of all the lungfish and possibly the closest living relative to the ancestors of tetrapods. Results Juvenile Neoceratodus have five spectrally distinct retinal visual pigments. A single type of rod photoreceptor contains a visual pigment with a wavelength of maximum absorbance (?max) at 540 nm. Four spectrally distinct single cone photoreceptors contain visual pigments with ?max at 366 (UVS), 479 (SWS), 558 (MWS) and 623 nm (LWS). No double cones were found. Adult lungfish do not possess UVS cones and, unlike juveniles, have ocular media that prevent ultraviolet light from reaching the retina. Yellow ellipsoidal/paraboloidal pigments in the MWS cones and red oil droplets in the LWS cones narrow the spectral sensitivity functions of these photoreceptors and shift their peak sensitivity to 584 nm and 656 nm, respectively. Modelling of the effects of these intracellular spectral filters on the photoreceptor colour space of Neoceratodus suggests that they enhance their ability to discriminate objects, such as plants and other lungfishes, on the basis of colour. Conclusion The presence of a complex colour vision system based on multiple cone types and intracellular spectral filters in lungfishes suggests that many of the ocular characteristics seen in terrestrial or secondarily aquatic vertebrates, such as birds and turtles, may have evolved in shallow water prior to the transition onto land. Moreover, the benefits of spectral filters for colour discrimination apply equally to purely aquatic species as well as semi-aquatic and terrestrial animals. The visual system of the Australian lungfish resembles that of terrestrial vertebrates far more closely than that of other sarcopterygian fish. This supports the idea that lungfishes, and not the coelacanth, are the closest living relatives of the ancestors of tetrapods.

Hart, Nathan S; Bailes, Helena J; Vorobyev, Misha; Marshall, N Justin; Collin, Shaun P

2008-01-01

360

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.

Idnurm, Alexander; Verma, Surbhi; Corrochano, Luis M.

2010-01-01

361

The molecular basis of mechanisms underlying polarization vision  

PubMed Central

The underlying mechanisms of polarization sensitivity (PS) have long remained elusive. For rhabdomeric photoreceptors, questions remain over the high levels of PS measured experimentally. In ciliary photoreceptors, and specifically cones, little direct evidence supports any type of mechanism. In order to promote a greater interest in these fundamental aspects of polarization vision, we examined a varied collection of studies linking membrane biochemistry, protein–protein interactions, molecular ordering and membrane phase behaviour. While initially these studies may seem unrelated to polarization vision, a common narrative emerges. A surprising amount of evidence exists demonstrating the importance of protein–protein interactions in both rhabdomeric and ciliary photoreceptors, indicating the possible long-range ordering of the opsin protein for increased PS. Moreover, we extend this direction by considering how such protein paracrystalline organization arises in all cell types from controlled membrane phase behaviour and propose a universal pathway for PS to occur in both rhabdomeric and cone photoreceptors.

Roberts, Nicholas W.; Porter, Megan L.; Cronin, Thomas W.

2011-01-01

362

Melanopsin and Mechanisms of Non-visual Ocular Photoreception*  

PubMed Central

In addition to rods and cones, the mammalian eye contains a third class of photoreceptor, the intrinsically photosensitive retinal ganglion cell (ipRGC). ipRGCs are heterogeneous irradiance-encoding neurons that primarily project to non-visual areas of the brain. Characteristics of ipRGC light responses differ significantly from those of rod and cone responses, including depolarization to light, slow on- and off-latencies, and relatively low light sensitivity. All ipRGCs use melanopsin (Opn4) as their photopigment. Melanopsin resembles invertebrate rhabdomeric photopigments more than vertebrate ciliary pigments and uses a Gq signaling pathway, in contrast to the Gt pathway used by rods and cones. ipRGCs can recycle chromophore in the absence of the retinal pigment epithelium and are highly resistant to vitamin A depletion. This suggests that melanopsin employs a bistable sequential photon absorption mechanism typical of rhabdomeric opsins.

Sexton, Timothy; Buhr, Ethan; Van Gelder, Russell N.

2012-01-01

363

A retinitis pigmentosa GTPase regulator (RPGR)- deficient mouse model for X-linked retinitis pigmentosa (RP3)  

PubMed Central

The X-linked RP3 locus codes for retinitis pigmentosa GTPase regulator (RPGR), a protein of unknown function with sequence homology to the guanine nucleotide exchange factor for Ran GTPase. We created an RPGR-deficient murine model by gene knockout. In the mutant mice, cone photoreceptors exhibit ectopic localization of cone opsins in the cell body and synapses and rod photoreceptors have a reduced level of rhodopsin. Subsequently, both cone and rod photoreceptors degenerate. RPGR was found normally localized to the connecting cilia of rod and cone photoreceptors. These data point to a role for RPGR in maintaining the polarized protein distribution across the connecting cilium by facilitating directional transport or restricting redistribution. The function of RPGR is essential for the long-term maintenance of photoreceptor viability.

Hong, Dong-Hyun; Pawlyk, Basil S.; Shang, Jingzi; Sandberg, Michael A.; Berson, Eliot L.; Li, Tiansen

2000-01-01

364

Evolution of colour vision in mammals  

PubMed Central

Colour vision allows animals to reliably distinguish differences in the distributions of spectral energies reaching the eye. Although not universal, a capacity for colour vision is sufficiently widespread across the animal kingdom to provide prima facie evidence of its importance as a tool for analysing and interpreting the visual environment. The basic biological mechanisms on which vertebrate colour vision ultimately rests, the cone opsin genes and the photopigments they specify, are highly conserved. Within that constraint, however, the utilization of these basic elements varies in striking ways in that they appear, disappear and emerge in altered form during the course of evolution. These changes, along with other alterations in the visual system, have led to profound variations in the nature and salience of colour vision among the vertebrates. This article concerns the evolution of colour vision among the mammals, viewing that process in the context of relevant biological mechanisms, of variations in mammalian colour vision, and of the utility of colour vision.

Jacobs, Gerald H.

2009-01-01

365

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

2013-08-07

366

Eye evolution: common use and independent recruitment of genetic components  

PubMed Central

Animal eyes can vary in complexity ranging from a single photoreceptor cell shaded by a pigment cell to elaborate arrays of these basic units, which allow image formation in compound eyes of insects or camera-type eyes of vertebrates. The evolution of the eye requires involvement of several distinct components—photoreceptors, screening pigment and genes orchestrating their proper temporal and spatial organization. Analysis of particular genetic and biochemical components shows that many evolutionary processes have participated in eye evolution. Multiple examples of co-option of crystallins, G? protein subunits and screening pigments contrast with the conserved role of opsins and a set of transcription factors governing eye development in distantly related animal phyla. The direct regulation of essential photoreceptor genes by these factors suggests that this regulatory relationship might have been already established in the ancestral photoreceptor cell.

Vopalensky, Pavel; Kozmik, Zbynek

2009-01-01

367

Polymorphic New World monkeys with more than three M/L cone types  

NASA Astrophysics Data System (ADS)

Most New World (platyrrhine) monkeys have M/L cone photopigment polymorphisms that map directly into individual variations in visual sensitivity and color vision. We used electroretinogram flicker photometry to examine M/L cone photopigments in the New World monkey Callicebus moloch (the dusky Titi). Like other New World monkeys, this species has an M/L cone photopigment polymorphism that reflects the presence of X-chromosome opsin gene alleles. However, unlike other platyrrhines in which three M/L photopigments are typical, Callicebus has a total of five M/L cone photopigments. The peak sensitivity values for these pigments extend across the range from 530 to 562 nm. The result is an enhanced array of potential color vision phenotypes in this species.

Jacobs, Gerald H.; Deegan, Jess F.

2005-10-01

368

Computational modeling of structure-function of g protein-coupled receptors with applications for drug design.  

PubMed

G protein-coupled receptors (GPCRs) mediate senses such as odor, taste, vision, and pain in mammals. In addition, important cell recognition and communication processes often involve GPCRs. Many diseases involve malfunction of GPCRs, making them important targets for drug development. Indeed, greater than 50 % of all marketed therapeutics act on those receptors. Unfortunately, the atomic-level structures are only available for rhodopsin, beta2AR, beta1AR, A2A adenosin and opsin. In silico computational methods, employing receptor-based modeling, offer a rational approach in the design of drugs targeting GPCRs. These approaches can be used to understand receptor selectivity and species specificity of drugs that interact with GPCRs. This review gives an overview of current computational approaches to GPCR model building; ligand-receptor interaction for drug design; and molecular mechanism of GPCR activation from simulation. PMID:20158474

Li, Y Y; Hou, T J; Goddard, W A

2010-01-01

369

Amino acid residues controlling the properties and functions of rod and cone visual pigments.  

PubMed

The visual transduction processes in rod and cone photoreceptor cells are initiated by photon absorption by the different types of visual pigments. In relation to the functional difference between these cells, cone visual pigments in chicken retinas exhibit faster regeneration from 11-cis-retinal and opsin and faster decay of physiologically active intermediate (Meta II) than rod visual pigment, rhodopsin. Replacement of the amino acid residue at position 122 of chicken rhodopsin by the residues present in the respective cone pigments dramatically changes both the decay rate of Meta II and the rate of regeneration into those of the cone pigment-type, indicating that the residue at this position is a major determinant controlling these properties. Thus, the single replacement of amino acid residue at this position would be one of the key steps of the divergence into twilight and daylight vision. PMID:10614050

Shichida, Y; Imai, H

1999-01-01

370

Enlightening the brain: linking deep brain photoreception with behavior and physiology.  

PubMed

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

2013-05-26

371

All-optical control of neuronal function via optical delivery of light-sensitive proteins and optogenetic stimulation  

NASA Astrophysics Data System (ADS)

While pulsed laser beams have been used for stimulation of neurons, cellular specificity during optical stimulation is achieved by photo-sensitization of genetically-targeted cells by optogenetic means. However, till date, the process of optogenetic-sensitization primarily involves use of viral vectors. In rare occasions, electroporation has been used. Here, we report an all-optical method in which pulsed laser beam is used for delivery of genes, encoding optogenetic probes, to spatially-targeted cells, followed by optogenetic stimulation and optical detection of the activation process. Use of laser microbeam enabled highly precise spatially-patterned delivery of optogenes, as confirmed by expression of conjugated fluorescent protein. Light-activation of opsin-expressing cells was confirmed by calcium-imaging. The laser-assisted expression of optogenetic probes in spatially-targeted regions in combination with light-assisted activation and optical detection of neural activity will help in better understanding of the neuronal circuitry.

Villalobos, Alex; Gu, Ling; Mohanty, Samarendra

2012-02-01

372

The photophysics of isolated protein chromophores  

NASA Astrophysics Data System (ADS)

Gas-phase absorption properties of chromophores of several photoactive proteins have been studied experimentally at the electrostatic heavy-ion storage ring ELISA in Aarhus. The absorption wavelength has been calculated using an augmented effective Hamiltonian technique based on the multiconfigurational quasi-degenerate perturbation theory. The results have been compared to those of widely used state-specific second-order perturbation theory formalisms and their multistate extensions and also to ground-state linear response methods. It would appear that ab initio theory is now at a stage where the intrinsic properties of the chromophore molecules may be predicted with reasonable precision. There is evidence that in terms of absorption there is almost vacuum-like conditions in the hydrophobic interior of some proteins like the green fluorescent protein (GFP). In others, like for example the visual opsins, some significant perturbations are responsible for colour tuning.

Andersen, L. H.; Bochenkova, A. V.

2009-01-01

373

[Spectral sensitivity and visual pigments of the coastal crab Hemigrapsus sanguineus].  

PubMed

It has been shown that the compound eye of the coastal crab has one photosensitive pigment rhodopsin and screening pigments, black and orange one. The orange pigment has lambda max = 480 nm, rhodopsin in digitonin is stable towards hydroxylamin action, has lambda max = 490-495 nm and after bleaching is transformed into free retinene and opsin. The pigments with lambda max = 430 and 475 nm of the receptor part of the eye are also solubilized. These pigments are not photosensitive but they dissociate under the effect of hydroxylamine. The curye of spectral sensitivity of the coastal crab has the basic maximum at approximately 525 nm and the additional one at 450 nm, which seems to be provided by a combination of the visual pigment--rhodopsin (lambda max 500 nm) with a carotinoid filter (lambda max 480-490). Specific features of the visual system of coastal crab are discussed. PMID:7397264

Shukoliukov, S A; Zak, P P; Kalamkarov, G R; Kalishevich, O O; Ostrovski?, M A

374

Photochemical activation of TRPA1 channels in neurons and animals.  

PubMed

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 zebrafish and mice. To our surprise, 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 nontransgenic 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 J; Roth, Bryan L; Hamblin, Michael R; Zylka, Mark J; Milan, David J; Peterson, Randall T

2013-02-10

375

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.

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

376

Extraretinal photoreceptors in the brain of the crayfish Cherax destructor.  

PubMed

Two clusters of red-brown pigmented cell somata lie among other cell somata along the anterior margin of the cerebral ganglion in the crayfish Cherax destructor. Electron micrographs show these cells to contain round electron dense pigment granules and that the cell membranes of two or more adjacent cells fold together to form rhabdom-like structures. The pigmented cells specifically bind a monoclonal antibody against the major species of opsin in R1-7 retinula cells of the compound eye of Cherax. When stimulated with light, the pigmented cells respond with a receptor potential-like depolarization. The axons of the pigmented cells terminate in the neuropil of the protocerebral bridge, together with neuronal elements that label with antibodies against serotonin and substance P. We suggest that the brain photoreceptors of the crayfish are important in the entrainment of circadian rhythms. PMID:1695916

Sandeman, D C; Sandeman, R E; de Couet, H G

1990-06-01

377

Modulation of the Absorption Maximum of Rhodopsin by Amino Acids in the C-terminus†  

PubMed Central

Vision begins when light is absorbed by visual pigments. It is commonly believed that the absorption spectra of visual pigments are modulated by interactions between the retinal and amino acids within or near 4.5 Å of the retinal in the transmembrane (TM) segments. However, this dogma has not been rigorously tested. In this study, we show that the retinal-opsin interactions extend well beyond the retinal binding pocket. We found that, although it is positioned outside of TM segments, the C-terminus of the rhodopsin in the rockfish longspine thornyhead (Sebastolobus altivelis) modulates its ?max by interacting mainly with the last TM segment. Our results illustrate how amino acids in the C-terminus are likely to interact with the retinal. We anticipate our analyses to be a starting point for viewing the spectral tuning of visual pigments as interactions between the retinal and key amino acids that are distributed throughout the entire pigment.

Yokoyama, Shozo; Tada, Takashi; Yamato, Takahisa

2008-01-01

378

Optogenetics in epilepsy.  

PubMed

Optogenetics, the use of light to stimulate or inhibit neural circuits via viral transduction of protein channels, has emerged as a possible method of treating epilepsy. By introducing viral vectors carrying algal-derived cation or anion channels, known as opsins, neurons that initiate or propagate seizures may be silenced. To date, studies using this technique have been performed in animal models, and current efforts are moving toward more sophisticated nonhuman primate models. In this paper, the authors present a brief overview of the development of optogenetics and review recent studies investigating optogenetic modification of circuits involved in seizures. Further developments in the field are explored, with an emphasis on how optogenetics may influence future neurosurgical interventions. PMID:23724838

Bentley, J Nicole; Chestek, Cindy; Stacey, William C; Patil, Parag G

2013-06-01

379

Adaptive optics retinal imaging reveals S-cone dystrophy in tritan color-vision deficiency  

PubMed Central

Tritan color-vision deficiency is an autosomal dominant disorder associated with mutations in the short-wavelength-sensitive- (S-) cone-pigment gene. An unexplained feature of the disorder is that individuals with the same mutation manifest different degrees of deficiency. To date, it has not been possible to examine whether any loss of S-cone function is accompanied by physical disruption in the cone mosaic. Two related tritan subjects with the same novel mutation in their S-cone-opsin gene, but different degrees of deficiency, were examined. Adaptive optics was used to obtain high-resolution retinal images, which revealed distinctly different S-cone mosaics consistent with their discrepant phenotypes. In addition, a significant disruption in the regularity of the overall cone mosaic was observed in the subject completely lacking S-cone function. These results taken together with other recent findings from molecular genetics indicate that, with rare exceptions, tritan deficiency is progressive in nature.

Baraas, Rigmor C.; Carroll, Joseph; Gunther, Karen L.; Chung, Mina; Williams, David R.; Foster, David H.; Neitz, Maureen

2007-01-01

380

Novel insights into non-image forming visual processing in the retina  

PubMed Central

A small subset of retinal ganglion cells projecting to the suprachiasmatic nucleus and other brain areas, is implicated in non-image forming visual responses to environmental light such as the pupillary light reflex, seasonal adaptations in physiology, photic inhibition of nocturnal melatonin release, and modulation of sleep, alertness and activity. These cells are intrinsically photosensitive (ipRGCs) and express an opsin-like photopigment called melanopsin. Two recent studies utilizing selective genetic ablation of ipRGCs demonstrate the key role of these inner retinal cells in conveying luminance signals to the brain for non-image forming visual processing. These findings advance our understanding of functional organization of a novel photosensory system in the mammalian retina, demonstrating well-defined roles for ipRGCs in circadian timing and other homeostatic functions related to ambient illumination.

Schmidt, Tiffany M.; Kofuji, Paulo

2009-01-01

381

Crystal Structure of Rhodopsin: A Template for Cone Visual Pigments and Other G Protein-coupled Receptors  

SciTech Connect

The crystal structure of rhodopsin has provided the first three-dimensional molecular model for a G-protein-coupled receptor (GPCR). Alignment of the molecular model from the crystallographic structure with the helical axes seen in cryo-electron microscopic (cryo-EM) studies provides an opportunity to investigate the properties of the molecule as a function of orientation and location within the membrane. In addition, the structure provides a starting point for modeling and rational experimental approaches of the cone pigments, the GPCRs in cone cells responsible for color vision. Homology models of the cone pigments provide a means of understanding the roles of amino acid sequence differences that shift the absorption maximum of the retinal chromophore in the environments of different opsins.

Stenkamp, R. E.

2002-01-01

382

Immunocytochemical Evidence of Tulp1-dependent Outer Segment Protein Transport Pathways in Photoreceptor Cells  

PubMed Central

Tulp1 is a protein of unknown function exclusive to rod and cone photoreceptor cells. Mutations in the gene cause autosomal recessive retinitis pigmentosa in humans and photoreceptor degeneration in mice. In tulp1?/? mice, rod and cone opsins are mislocalized, and rhodopsin-bearing extracellular vesicles accumulate around the inner segment, indicating that Tulp1 is involved in protein transport from the inner segment to the outer segment. To investigate this further, we sought to define which outer segment transport pathways are Tulp1-dependent. We used immunohistochemistry to examine the localization of outer segment proteins in tulp1?/? photoreceptors, prior to retinal degeneration. We also surveyed the condition of inner segment organelles and rhodopsin transport machinery proteins. Herein, we show that guanylate cyclase 1 and guanylate cyclase activating proteins 1 and 2 are mislocalized in the absence of Tulp1. Furthermore, arrestin does not translocate to the outer segment in response to light stimulation. Additionally, data from the tulp1?/? retina adds to the understanding of peripheral membrane protein transport, indicating that rhodopsin kinase and transducin do not co-transport in rhodopsin carrier vesicles and phosphodiesterase does not co-transport in guanylate cyclase carrier vesicles. These data implicate Tulp1 in the transport of selective integral membrane outer segment proteins and their associated proteins, specifically, the opsin and guanylate cyclase carrier pathways. The exact role of Tulp1 in outer segment protein transport remains elusive. However, without Tulp1, two rhodopsin transport machinery proteins exhibit abnormal distribution, Rab8 and Rab11, suggesting a role for Tulp1 in vesicular docking and fusion at the plasma membrane near the connecting cilium.

Grossman, Gregory H.; Watson, Rao F.; Pauer, Gayle J.T.; Bollinger, Kathryn; Hagstrom, Stephanie A.

2011-01-01

383

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.

Frentiu, Francesca D.; Bernard, Gary D.; Cuevas, Cristina I.; Sison-Mangus, Marilou P.; Prudic, Kathleen L.; Briscoe, Adriana D.

2007-01-01

384

Optogenetic evidence that pallidal projections, not nigral projections, from the nucleus accumbens core are necessary for reinstating cocaine seeking.  

PubMed

The core subcompartment of the nucleus accumbens (NAcore) contributes significantly to behavioral responses following motivationally relevant stimuli, including drug-induced, stress-induced, and cue-induced reinstatement of cocaine seeking. Projections from NAcore that could carry information necessary to initiate reinstated cocaine seeking include outputs via the indirect pathway to the dorsolateral subcompartment of the ventral pallidum (dlVP) and through the direct pathway to the medial substantia nigra (SN). Here we used an optogenetic strategy to determine whether the dlVP or nigral projections from the NAcore are necessary for cocaine seeking initiated by a cocaine and conditioned cue combination in rats extinguished from cocaine self-administration. Rats were pretreated in the NAcore with an adeno-associated virus expressing the inhibitory opsin archaerhodopsin, and fiber-optic cannulae were implanted above the indirect pathway axon terminal field in the dlVP, or the direct pathway terminal field in the SN. Inhibiting the indirect pathway to the dlVP, but not the direct pathway to the SN, prevented cocaine-plus-cue-induced reinstatement. We also examined projections back to the NAcore from the ventral tegmental area (VTA) and dlVP. Inhibiting the dlVP to NAcore projection did not alter, while inhibiting VTA afferents abolished reinstated cocaine seeking. Localization of green fluorescent protein reporter expression and whole-cell patch electrophysiology were used to verify opsin expression. These data reveal a circuit involving activation of VTA inputs to the NAcore and NAcore projections through the indirect pathway to the dlVP as critical for cocaine-plus-cue-induced reinstatement of cocaine seeking. PMID:23966687

Stefanik, Michael T; Kupchik, Yonatan M; Brown, Robyn M; Kalivas, Peter W

2013-08-21

385

Factors affecting the absorption maxima of acidic forms of bacteriorhodopsin. A study with artificial pigments  

SciTech Connect

The absorption maximum (568 nm) of light-adapted bacteriorhodopsin bR568 undergoes reversible changes after acidification. At pH 2.9, the absorption shifts to 605 nm (forming bR605) and it blue shifts to 565 nm, after further acidification to pH approximately 0.5 (forming bR565). Molecular models accounting for such acid-induced changes are relevant to the structure and function of bacteriorhodopsin. In the present study we approached the problem by applying artificial bR pigments based on selectively modified synthetic retinals. This may allow direct identification of the specific regions in the retinal binding site where the above changes in the protein-retinal interactions take place. We investigated the spectroscopic effects of acid in a variety of artificial pigments, including cyaninelike retinals, retinals bearing bulky groups at C4, short polyenes, and retinals in which the beta-ionone ring was substituted by aromatic rings. The results provide direct evidence for the hypothesis that the generation of bR605 is due to changes in polyene-opsin interactions in the vicinity of the Schiff base linkage. The second transition (to bR565) was not observed in artificial pigments bearing major changes in the ring structure of the retinal. Two approaches accounting for this observation are presented. One argues that the generation of bR565 is associated with acid-induced changes in retinal-protein interactions in the vicinity of the retinal ring. The second involves changes in polyene-opsin interactions in the vicinity of the Schiff base linkage.

Albeck, A.; Friedman, N.; Sheves, M.; Ottolenghi, M. (Weizmann Institute of Science, Rehovot (Israel))

1989-12-01

386

Functional characterization of an arrestin gene on insecticide resistance of Culex pipiens pallens  

PubMed Central

Background Continuous and excessive application of insecticides has resulted in the rapid development of insecticide resistance in several mosquito species, including Culex pipiens pallens. Previous studies in our laboratory found that arrestin gene expression was higher in the deltamethrin-resistant (DR) strain than in the deltamethrin-susceptible (DS) strain of Cx. pipiens pallens. Similarly, other studies reported that arrestin was highly expressed in permethrin-resistant Cx. quinquefasciatus and in dichlorodiphenyltrichloroethane (DDT)-resistant Drosophila melanogaster. Methods Full-length cDNAs of an arrestin gene were cloned from Cx. pipiens pallens via polymerase chain reaction (PCR) and rapid amplification of cDNA end (RACE). The mRNA levels of the arrestin gene in the whole life cycle of DR and DS strains of Cx. pipiens pallens were investigated via quantitative real-time PCR. In addition, the relationship between arrestin and deltamethrin (DM) resistance were identified using genetic overexpression strategies and arrestin RNAi in mosquito cells. Cell viability was analyzed with cholecystokinin octapeptide after DM treatment. Moreover, the mRNA levels of cytochrome P450 6A1 (CYP6A1) and opsin in the transfected cells and controls were analyzed. Results Complete arrestin gene sequence was cloned and expressed throughout the life cycle of Cx. pipiens pallens. Moreover, arrestin was significantly upregulated in the DR strain, compared with that in the DS strain at the egg, pupae, and adult stages. Arrestin overexpression comparably increased the mosquito cell viability, whereas arrestin knockdown by siRNA decreased mosquito cell viability with deltamethrin (DM) treatment. Meanwhile, the mRNA levels of CYP6A1 and opsin were upregulated in mosquito cells transfected with arrestin and downregulated in mosquito cells with arrestin knockdown. Conclusion This study presented the first evidence that arrestin might be associated with insecticide resistance in Cx. pipiens pallens.

2012-01-01

387

Violet Light Down-Regulates the Expression of Specific Differentiation Markers through Rhodopsin in Normal Human Epidermal Keratinocytes.  

PubMed

Several recent reports have demonstrated that photoreceptors are expressed in human skin. The rod and cone photoreceptor-like proteins are expressed in human skin and rhodopsin, long wavelength-opsin, and short wavelength-opsin are also present in cultured murine melanocytes. Furthermore, the photopigment rhodopsin is expressed in human melanocytes and is involved in ultraviolet A phototransduction which induces early melanin synthesis. In this study, we investigated whether rhodopsin is expressed and plays any physiological roles in the normal human epidermal keratinocytes (NHEKs). We found that rhodopsin was expressed and localized on the plasma membrane in NHEKs, and only violet light among several wavelengths within the visible range significantly increased the expression of rhodopsin mRNA. We further found that rhodopsin over-expression decreased the mRNA expression levels of keratinocyte differentiation markers, such as keratin-1 and keratin-10, and violet light also decreased the mRNA expression levels of keratinocyte differentiation markers and these decreased expression levels were recovered by a rhodopsin-directed siRNA. Moreover, we further demonstrated that violet light significantly decreased the phosphorylation levels of cAMP responsive element-binding protein (CREB) and that it more effectively decreased the phosphorylation of CREB when rhodopsin was over-expressed. In addition, we observed that pertussis toxin, a G?i protein inhibitor, restored the rhodopsin-induced decrease in the differentiation markers in NHEKs. Taken together, these results suggest that rhodopsin down-regulates the expression levels of specific keratinocyte differentiation markers via the G?i signaling pathway in NHEKs. PMID:24069221

Kim, Hyoung-June; Son, Eui Dong; Jung, Ji-Yong; Choi, Hyun; Lee, Tae Ryong; Shin, Dong Wook

2013-09-17

388

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.

Seiler, M.J.; Jones, B.W.; Aramant, R.B.; Yang, P.B.; Keirstead, H.S.; Marc, R.E.

2012-01-01

389

Conditional and Specific Cell Ablation in the Marine Annelid Platynereis dumerilii  

PubMed Central

The marine annelid Platynereis dumerilii has become a model system for evo-devo, neurobiology and marine biology. The functional assessment of its cell types, however, has so far been very limited. Here we report on the establishment of a generally applicable, cell type specific ablation technique to overcome this restriction. Using a transgenic strain expressing the bacterial enzyme nitroreductase (ntr) under the control of the worm’s r-opsin1 locus, we show that the demarcated photoreceptor cells can be specifically ablated by the addition of the prodrug metronidazole (mtz). TUNEL staining indicates that ntr expressing cells undergo apoptotic cell death. As we used a transgenic strain co-expressing ntr with enhanced green fluorescent protein (egfp) coding sequence, we were able to validate the ablation of photoreceptors not only in fixed tissue, using r-opsin1 riboprobes, but also by monitoring eGFP+ cells in live animals. The specificity of the ablation was demonstrated by the normal presence of the eye pigment cells, as well as of neuronal markers expressed in other cells of the brain, such as phc2, tyrosine hydroxylase and brn1/2/4. Additional analyses of the position of DAPI stained nuclei, the brain’s overall neuronal scaffold, as well as the positions and projections of serotonergic neurons further confirmed that mtz treatment did not induce general abnormalities in the worm’s brain. As the prodrug is administered by adding it to the water, targeted ablation of specific cell types can be achieved throughout the life of the animal. We show that ablation conditions need to be adjusted to the size of the worms, likely due to differences in the penetration of the prodrug, and establish ablation conditions for worms containing 10 to 55 segments. Our results establish mtz/ntr mediated conditional cell ablation as a powerful functional tool in Platynereis.

Veedin-Rajan, Vinoth Babu; Fischer, Ruth M.; Raible, Florian; Tessmar-Raible, Kristin

2013-01-01

390

Violet Light Down-Regulates the Expression of Specific Differentiation Markers through Rhodopsin in Normal Human Epidermal Keratinocytes  

PubMed Central

Several recent reports have demonstrated that photoreceptors are expressed in human skin. The rod and cone photoreceptor-like proteins are expressed in human skin and rhodopsin, long wavelength-opsin, and short wavelength-opsin are also present in cultured murine melanocytes. Furthermore, the photopigment rhodopsin is expressed in human melanocytes and is involved in ultraviolet A phototransduction which induces early melanin synthesis. In this study, we investigated whether rhodopsin is expressed and plays any physiological roles in the normal human epidermal keratinocytes (NHEKs). We found that rhodopsin was expressed and localized on the plasma membrane in NHEKs, and only violet light among several wavelengths within the visible range significantly increased the expression of rhodopsin mRNA. We further found that rhodopsin over-expression decreased the mRNA expression levels of keratinocyte differentiation markers, such as keratin-1 and keratin-10, and violet light also decreased the mRNA expression levels of keratinocyte differentiation markers and these decreased expression levels were recovered by a rhodopsin-directed siRNA. Moreover, we further demonstrated that violet light significantly decreased the phosphorylation levels of cAMP responsive element-binding protein (CREB) and that it more effectively decreased the phosphorylation of CREB when rhodopsin was over-expressed. In addition, we observed that pertussis toxin, a G?i protein inhibitor, restored the rhodopsin-induced decrease in the differentiation markers in NHEKs. Taken together, these results suggest that rhodopsin down-regulates the expression levels of specific keratinocyte differentiation markers via the G?i signaling pathway in NHEKs.

Kim, Hyoung-June; Son, Eui Dong; Jung, Ji-Yong; Choi, Hyun; Lee, Tae Ryong; Shin, Dong Wook

2013-01-01

391

Intrinsic Light Response of Retinal Horizontal Cells of Teleosts  

PubMed Central

The discovery of intrinsically photosensitive retinal ganglion cells (ipRGCs) has overthrown the long-held belief that rods and cones are the exclusive retinal photoreceptors1, 2. IpRGCs use melanopsin3 as the photopigment, and mediate non-image-forming visual functions such as circadian photoentrainment. In fish, melanopsin has been suggested by in situ hybridization studies to be in retinal horizontal cells (HCs)4-6– lateral association neurons critical for creating the center-surround receptive fields of visual neurons. Are fish HCs, then, possibly also intrinsically photosensitive? This iconoclastic notion was examined previously in flat-mount roach retina, but all HC light response disappeared after synaptic transmission was blocked6, making any conclusion difficult. To directly examine this question, we have now recorded from single, acutely dissociated fish HCs. We found that light induced a response in cone HCs but not rod HCs from catfish, consisting of a modulation of the nifedipine-sensitive, voltage-gated Ca current. The light response was extremely slow, lasting for many minutes. Similar light responses were observed in a high percentage of goldfish HCs. We have cloned from catfish two melanopsin genes and one vertebrate ancient (VA) opsin gene. In situ hybridization indicated that melanopsin, but less likely VA opsin, was expressed in the HC layer of catfish retina. This intrinsic light response may serve to modulate, over a long time scale, lateral inhibition mediated by these cells. Thus, at least in some vertebrates, there are retinal non-rod/non-cone photoreceptors involved primarily in image-forming vision.

Cheng, Ning; Tsunenari, Takashi; Yau, King-Wai

2009-01-01

392

PDA (prolonged depolarizing afterpotential)-defective mutants: the story of nina's and ina's--pinta and santa maria, too.  

PubMed

Our objective is to present a comprehensive view of the PDA (prolonged depolarizing afterpotential)-defective Drosophila mutants, nina's and ina's, from the discussion of the PDA and the PDA-based mutant screening strategy to summaries of the knowledge gained through the studies of mutants generated using the strategy. The PDA is a component of the light-evoked photoreceptor potential that is generated when a substantial fraction of rhodopsin is photoconverted to its active form, metarhodopsin. The PDA-based mutant screening strategy was adopted to enhance the efficiency and efficacy of ERG (electroretinogram)-based screening for identifying phototransduction-defective mutants. Using this strategy, two classes of PDA-defective mutants were identified and isolated, nina and ina, each comprising multiple complementation groups. The nina mutants are characterized by allele-dependent reduction in the major rhodopsin, Rh1, whereas the ina mutants display defects in some aspects of functions related to the transduction channel, TRP (transient receptor potential). The signaling proteins that have been identified and elucidated through the studies of nina mutants include the Drosophila opsin protein (NINAE), the chaperone protein for nascent opsin (NINAA), and the multifunctional protein, NINAC, required in multiple steps of the Drosophila phototransduction cascade. Also identified by the nina mutants are some of the key enzymes involved in the biogenesis of the rhodopsin chromophore. As for the ina mutants, they led to the discovery of the scaffold protein, INAD, responsible for the nucleation of the supramolecular signaling complex. Also identified by the ina mutants is one of the key members of the signaling complex, INAC (ePKC), and two other proteins that are likely to be important, though their roles in the signaling cascade have not yet been fully elucidated. In most of these cases, the protein identified is the first member of its class to be so recognized. PMID:22283778

Pak, William L; Shino, Shikoh; Leung, Hung-Tat

2012-01-27

393

Role of LRAT on the Retinoid Isomerase Activity and Membrane Association of Rpe65*  

PubMed Central

Absorption of a photon by a vertebrate opsin pigment induces 11-cis to all-trans isomerization of its retinaldehyde chromophore. Restoration of light sensitivity to the bleached opsin requires chemical re-isomerization of the chromophore via an enzyme pathway called the visual cycle. The retinoid isomerase in this pathway is Rpe65, a membrane-associated protein in the retinal pigment epithelium