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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  

PubMed Central

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) is also associated with opsin gene diversity, we sequenced long wavelength-sensitive (LWS) opsin genes in six species of the family Poeciliidae. Results Sequences of four LWS opsin genes were amplified from the guppy genome and from mRNA isolated from adult guppy eyes. Variation in expression was quantified using qPCR. Three of the four genes encode opsins predicted to be most sensitive to different wavelengths of light because they vary at key amino acid positions. This family of LWS opsin genes was produced by a diversity of duplication events. One, an intronless gene, was produced prior to the divergence of families Fundulidae and Poeciliidae. Between-gene PCR and DNA sequencing show that two of the guppy LWS opsins are linked in an inverted orientation. This inverted tandem duplication event occurred near the base of the poeciliid tree in the common ancestor of Poecilia and Xiphophorus. The fourth sequence has been uncovered only in the genus Poecilia. In the guppies surveyed here, this sequence is a hybrid, with the 5' end most similar to one of the tandem duplicates and the 3' end identical to the other. Conclusion Enhanced wavelength discrimination, a possible consequence of opsin gene duplication and divergence, might have been an evolutionary prerequisite for color-based sexual selection and have led to the extraordinary coloration now observed in male guppies and in many other poeciliids.

2008-01-01

3

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

4

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

PubMed Central

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 proposed as candidate genes driving sexual selection in this family. To date the genomic organization of these genes has not been described in the family Poeciliidae, and little is known about the mechanisms regulating the expression of LWS opsins in any teleost. Results Two BAC clones containing the complete genomic repertoire of LWS opsin genes in the green swordtail fish, Xiphophorus helleri, were identified and sequenced. Three of the four LWS loci identified here were linked in a tandem array downstream of two tightly linked short wave-sensitive 2 (SWS2) opsin genes. The fourth LWS opsin gene, containing only a single intron, was not linked to the other three and is the product of a retrotransposition event. Genomic and phylogenetic results demonstrate that the LWS genes described here share a common evolutionary origin with those previously characterized in other poeciliids. Using qualitative RT-PCR and MSP we showed that each of the LWS and SWS2 opsins, as well as three other cone opsin genes and a single rod opsin gene, were expressed in the eyes of adult female and male X. helleri, contributing to six separate classes of adult retinal cone and rod cells with average ?max values of 365 nm, 405 nm, 459 nm, 499 nm, 534 nm and 568 nm. Comparative genomic analysis identified two candidate teleost opsin regulatory regions containing putative CRX binding sites and hormone response elements in upstream sequences of LWS gene regions of seven teleost species, including X. helleri. Conclusions We report the first complete genomic description of LWS and SWS2 genes in poeciliids. These data will serve as a reference for future work seeking to understand the relationship between LWS opsin genomic organization, gene expression, gene family evolution, sexual selection and speciation in this fish family.

2010-01-01

5

Relative LWS cone opsin expression determines optomotor thresholds in Malawi cichlid fish.  

PubMed

Associating quantitative genetic traits with quantitative behaviors is a relatively unexplored region of sensory neurobiology. The visual system is an ideal place to test models associating these levels of sensory perception. In this study, we reared cichlid fish from Lake Malawi in different ambient light environments. We then tested the visual sensitivities of these fish using the optomotor response (OMR) behavioral paradigm and measured the relative expression of cone opsin genes. We found that the light environment experienced by fish during development can alter gene expression, particularly as it applies to the long wavelength-sensitive (LWS) opsin gene. Also, fish from different rearing conditions exhibited different behavioral sensitivities. We combined these data with predictions of opsin pigment absorption by the different OMR stimuli to determine which cone types are most likely to influence the OMR behavior. While we hypothesized that this behavior would be controlled by a random-wiring model reflecting the expression of both medium wavelength-sensitive (MWS) and LWS opsins, our models suggest that only the LWS pigment is required to predict behavior. Furthermore, analyses show that LWS expression variation accounts for ~20% of the observed behavioral variance. This work confirms that sensory gene expression influences behavior in a predictable fashion. It also suggests that the neural wiring of basal visual pathways in cichlid fish may differ from that observed in mammals and zebrafish, but is similar to that described in goldfish. This finding has important implications for the evolution of the magnocellular neural pathway in teleosts. PMID:21992615

Smith, A R; Ma, K; Soares, D; Carleton, K L

2012-03-01

6

Androgens Increase lws Opsin Expression and Red Sensitivity in Male Three-Spined Sticklebacks  

PubMed Central

Optomotor studies have shown that three-spined sticklebacks (Gasterosteus aculeatus) are more sensitive to red during summer than winter, which may be related to the need to detect the red breeding colour of males. This study aimed to determine whether this change of red light sensitivity is specifically related to reproductive physiology. The mRNA levels of opsin genes were examined in the retinae of sexually mature and immature fish, as well as in sham-operated males, castrated control males, or castrated males implanted with androgen 11-ketoandrostenedione (11 KA), maintained under stimulatory (L16:D8) or inhibitory (L8:D16) photoperiods. In both sexes, red-sensitive opsin gene (lws) mRNA levels were higher in sexually mature than in immature fish. Under L16:D8, lws mRNA levels were higher in intact than in castrated males, and were up-regulated by 11 KA treatment in castrated males. Moreover, electroretinogram data confirmed that sexual maturation resulted in higher relative red spectral sensitivity. Mature males under L16:D8 were more sensitive to red light than males under L8:D16. Red light sensitivity under L16:D8 was diminished by castration, but increased by 11 KA treatment. Thus, in sexually mature male sticklebacks, androgen is a key factor in enhancing sensitivity to red light via regulation of opsin gene expression. This is the first study to demonstrate that sex hormones can regulate spectral vision sensitivity.

Shao, Yi Ta; Wang, Feng-Yu; Fu, Wen-Chun; Anraku, Kazuhiko; Chen, I-Shiung

2014-01-01

7

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

PubMed Central

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.

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

2006-01-01

8

The opsin repertoire of Jenynsia onca: a new perspective on gene duplication and divergence in livebearers  

Microsoft Academic Search

BACKGROUND: Jenynsia onca, commonly known as the one sided livebearer, is a member of the family Anablepidae. The opsin gene repertoires of J. onca's close relatives, the four-eyed fish (Anableps anableps) and the guppy (Poecilia reticulata), have been characterized and each found to include one unique LWS opsin. Currently, the relationship among LWS paralogs and orthologs in these species are

Diana J Windsor; Gregory L Owens

2009-01-01

9

The opsin repertoire of Jenynsia onca: a new perspective on gene duplication and divergence in livebearers  

PubMed Central

Background Jenynsia onca, commonly known as the one sided livebearer, is a member of the family Anablepidae. The opsin gene repertoires of J. onca's close relatives, the four-eyed fish (Anableps anableps) and the guppy (Poecilia reticulata), have been characterized and each found to include one unique LWS opsin. Currently, the relationship among LWS paralogs and orthologs in these species are unclear, making it difficult to test the hypotheses that link vision to morphology or life history traits. The phylogenetic signal appears to have been disrupted by gene conversion. Here we have sequenced the opsin genes of J. onca in order to resolve these relationships. Findings We identified nine visual opsins; LWS S180r, LWS S180, LWS P180, SWS1, SWS2A, SWS2B, RH1, RH2-1, and RH2-2. Key site analysis revealed only one unique haplotype, RH2-2, although this is unlikely to shift ?max significantly. LWS P180 was found to be a product of a gene conversion event with LWS S180, followed by convergence to a proline residue at the 180 site. Conclusion Jenynsia onca has at least 9 visual opsins: three LWS, one RH1, two RH2, one SWS1 and two SWS2. The presence of LWS P180 moves the location of the LWS P180-S180 tandem duplication event back to the base of the Poeciliidae-Anablepidae clade, expanding the number of species possessing this unusual blue shifted LWS opsin. The presence of the LWS P180 gene also confirms that gene conversion events have homogenized opsin paralogs in fish, just as they have in humans.

Windsor, Diana J; Owens, Gregory L

2009-01-01

10

A Single Enhancer Regulating the Differential Expression of Duplicated Red-Sensitive Opsin Genes in Zebrafish  

Microsoft Academic Search

A fundamental step in the evolution of the visual system is the gene duplication of visual opsins and differentiation between the duplicates in absorption spectra and expression pattern in the retina. However, our understanding of the mechanism of expression differentiation is far behind that of spectral tuning of opsins. Zebrafish (Danio rerio) have two red-sensitive cone opsin genes, LWS-1 and

Taro Tsujimura; Tomohiro Hosoya; Shoji Kawamura

2010-01-01

11

Multiple origins of the green-sensitive opsin genes in fish  

Microsoft Academic Search

Vertebrate opsins are divided into four major groups: RH1 (rhodopsins), RH2 (rhodopsinlike with various absorption sensitivities), SWS (short-wavelength sensitive), and LWS\\/MWS (long and middle-wavelength sensitive) groups. The green opsin genes (g101Afand g101Af) in a Mexican characin Astyanax fasciatus belong to the LWS\\/MWS group, whereas those in goldfish belong to the RH2 group (Yokoyama 1994, Mol Biol Evol 11:32–39). A newly

Elizabeth A. Register; Ruth Yokoyama; Shozo Yokoyama

1994-01-01

12

Rapid light-induced shifts in opsin expression: finding new opsins, discerning mechanisms of change, and implications for visual sensitivity.  

PubMed

Light-induced shifts in cone frequency and opsin expression occur in many aquatic species. Yet little is known about how quickly animals can alter opsin expression and, thereby, track their visual environments. Similarly, little is known about whether adult animals can alter opsin expression or whether shifts in opsin expression are limited to critical developmental windows. We took adult wild-caught bluefin killifish (Lucania goodei) from three different lighting environments (spring, swamp and variable), placed them under two different lighting treatments (clear vs. tea-stained water) and monitored opsin expression over 4 weeks. We measured opsin expression for five previously described opsins (SWS1, SWS2B, SWS2A, RH2-1 and LWS) as well as RH2-2 which we discovered via 454 sequencing. We used two different metrics of opsin expression. We measured expression of each opsin relative to a housekeeping gene and the proportional expression of each opsin relative to the total pool of opsins. Population and lighting environment had large effects on opsin expression which were present at the earliest time points indicating rapid shifts in expression. The two measures of expression produced radically different patterns. Proportional measures indicated large effects of light on SWS1 expression, whereas relative measures indicated no such effect. Instead, light had large effects on the relative expression of SWS2B, RH2-2, RH2-1 and LWS. We suggest that proportional measures of opsin expression are best for making inferences about colour vision, but that measures relative to a housekeeping gene are better for making conclusions about which opsins are differentially regulated. PMID:21749514

Fuller, Rebecca C; Claricoates, Kristin M

2011-08-01

13

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

Microsoft Academic Search

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

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

2011-01-01

14

Evolution of opsin genes reveals a functional role of vision in the echolocating little brown bat ( Myotis lucifugus)  

Microsoft Academic Search

Echolocating bats are able to orientate, navigate and forage without visual cues. To probe the role of vision in bats, we studied the visual opsin genes from the echolocating little brown bat (Myotis lucifugus). Short-wavelength sensitive (SWS1) opsin, middle\\/long-wavelength sensitive (M\\/LWS) opsin and rhodopsin cDNA sequences were identified from the Ensembl database and validated by the sequencing of genomic DNA.

Huabin Zhao; Dong Xu; Yingying Zhou; Jon Flanders; Shuyi Zhang

2009-01-01

15

Intra-retinal variation of opsin gene expression in the guppy (Poecilia reticulata).  

PubMed

Although behavioural experiments demonstrate that colouration influences mate choice in many species, a complete understanding of this form of signalling requires information about colour vision in the species under investigation. The guppy (Poecilia reticulata) has become a model species for the study of colour-based sexual selection. To investigate the role of opsin gene duplication and divergence in the evolution of colour-based mate choice, we used in situ hybridization to determine where the guppy's nine cone opsins are expressed in the retina. Long wavelength-sensitive (LWS) opsins were more abundant in the dorsal retina than in the ventral retina. One of the middle wavelength-sensitive opsins (RH2-1) exhibited the opposite pattern, while the other middle wavelength-sensitive opsin (RH2-2) and the short wavelength-sensitive opsins (SWS1, SWS2A and SWS2B) were expressed throughout the retina. We also found variation in LWS opsin expression among individuals. These observations suggest that regions of the guppy retina are specialized with respect to wavelength discrimination and/or sensitivity. Intra-retinal variability in opsin expression, which has been observed in several fish species, might be an adaptation to variation in the strength and spectral composition of light entering the eye from above and below. The discovery that opsin expression varies in the guppy retina may motivate new behavioural experiments designed to study its role in mate choice. PMID:21900472

Rennison, Diana J; Owens, Gregory L; Allison, W Ted; Taylor, John S

2011-10-01

16

Rod monochromacy and the coevolution of cetacean retinal opsins.  

PubMed

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

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

2013-04-01

17

Rod Monochromacy and the Coevolution of Cetacean Retinal Opsins  

PubMed Central

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

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

2013-01-01

18

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

Microsoft Academic Search

Background  Divergence within cis-regulatory sequences may contribute to the adaptive evolution of gene expression, but functional alleles in these regions\\u000a are difficult to identify without abundant genomic resources. Among African cichlid fishes, the differential expression of\\u000a seven opsin genes has produced adaptive differences in visual sensitivity. Quantitative genetic analysis suggests that cis-regulatory alleles near the SWS2-LWS opsins may contribute to this

Kelly E O’Quin; Daniel Smith; Zan Naseer; Jane Schulte; Samuel D Engel; Yong-Hwee E Loh; J Todd Streelman; Jeffrey L Boore; Karen L Carleton

2011-01-01

19

Pineal Opsin: A Nonvisual Opsin Expressed in Chick Pineal  

Microsoft Academic Search

Pineal opsin (P-opsin), an opsin from chick that is highly expressed in pineal but is not detectable in retina, was cloned by the polymerase chain reaction. It is likely that the P-opsin lineage diverged from the retinal opsins early in opsin evolution. The amino acid sequence of P-opsin is 42 to 46 percent identical to that of the retinal opsins.

Marianna Max; Peter J. McKinnon; Kenneth J. Seidenman; R. Keith Barrett; Meredithe L. Applebury; Joseph S. Takahashi; Robert F. Margolskee

1995-01-01

20

Thyroid hormone controls cone opsin expression in the retina of adult rodents.  

PubMed

Mammalian retinas display an astonishing diversity in the spatial arrangement of their spectral cone photoreceptors, probably in adaptation to different visual environments. Opsin expression patterns like the dorsoventral gradients of short-wave-sensitive (S) and middle- to long-wave-sensitive (M) cone opsin found in many species are established early in development and thought to be stable thereafter throughout life. In mouse early development, thyroid hormone (TH), through its receptor TR?2, is an important regulator of cone spectral identity. However, the role of TH in the maintenance of the mature cone photoreceptor pattern is unclear. We here show that TH also controls adult cone opsin expression. Methimazole-induced suppression of serum TH in adult mice and rats yielded no changes in cone numbers but reversibly altered cone patterns by activating the expression of S-cone opsin and repressing the expression of M-cone opsin. Furthermore, treatment of athyroid Pax8(-/-) mice with TH restored a wild-type pattern of cone opsin expression that reverted back to the mutant S-opsin-dominated pattern after termination of treatment. No evidence for cone death or the generation of new cones from retinal progenitors was found in retinas that shifted opsin expression patterns. Together, this suggests that opsin expression in terminally differentiated mammalian cones remains subject to control by TH, a finding that is in contradiction to previous work and challenges the current view that opsin identity in mature mammalian cones is fixed by permanent gene silencing. PMID:21451022

Glaschke, Anika; Weiland, Jessica; Del Turco, Domenico; Steiner, Marianne; Peichl, Leo; Glösmann, Martin

2011-03-30

21

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

PubMed Central

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

2011-01-01

22

Spatio-temporal characterization of retinal opsin gene expression during thyroid hormone-induced and natural development of rainbow trout.  

PubMed

The abundance and spatial distribution of retinal cone photoreceptors change during thyroid hormone (TH)-induced and natural development of rainbow trout (Oncorhynchus mykiss). These changes are thought to allow the fish to adapt to different photic environments throughout its life history. To date, the ontogeny of rainbow trout cone photoreceptors has been examined using physiological and morphological approaches. In this study, we extended these observations by measuring opsin gene expression in retinal quadrants during natural and TH-induced development. Gene expression during natural development was investigated in retinae from fish at both parr and smolt stages. The role of TH in modulating opsin gene expression was determined in TH-treated parr and control fish sampled after two, nine, and 22 days of treatment. Total RNA was isolated from each retinal quadrant and steady-state opsin mRNA levels were measured using reverse transcriptase real-time quantitative polymerase chain reaction (QPCR) analysis. Expression of ultraviolet-sensitive opsin (SWS1), rod opsin (RH1), middle wavelength-sensitive opsin (RH2), and long wavelength-sensitive opsin (LWS) transcripts vary spatially in the parr retina. Smolts, compared to parr, had downregulated SWS1 expression in all quadrants, lower LWS expression dorsally, higher RH1 expression nasally, and higher RH2 expression dorsally. In TH-treated parr, SWS1 opsin expression was downregulated in the nasal quadrants by two days. SWS1 displayed the greatest degree of downregulation in all quadrants after nine days of treatment, with an increase in short wavelength-sensitive (SWS2) and RH2 opsin mRNA expression in the temporal quadrants. This study reveals that opsin genes display spatially significant differences within rainbow trout retina in their level of mRNA expression, and that regulation of opsin expression is a dynamic process that is influenced by TH. This is particularly evident for SWS1 gene expression in parr following TH-induced and natural development. PMID:16638170

Veldhoen, Kathy; Allison, W Ted; Veldhoen, Nik; Anholt, Bradley R; Helbing, Caren C; Hawryshyn, Craig W

2006-01-01

23

In the four-eyed fish (Anableps anableps), the regions of the retina exposed to aquatic and aerial light do not express the same set of opsin genes.  

PubMed

The four-eyed fish, Anableps anableps, has eyes with unusual morphological adaptations for simultaneous vision above and below water. The retina, for example, is divided such that one region receives light from the aerial field and the other from the aquatic field. To understand better the adaptive value of this partitioned retina, we characterized photoreceptor distribution using in situ hybridization. Cones expressing sws1, sws2b and rh2-2 (i.e. UV, and short wavelength-sensitive) opsins were found throughout the retina, whereas cones expressing rh2-1 (middle wavelength-sensitive) were largely limited to the ventral retina and those expressing lws (long wavelength-sensitive) opsins were only expressed in the dorsal retina. We next asked when this pattern evolved relative to the 'four-eyed' morphology. We characterized opsin expression in Jenynsia onca, a member of the sister genus to Anableps with typical teleost eye morphology. In J. onca, sws1, sws2b, rh2-2 and rh2-1 opsins were expressed throughout the retina; while lws opsins were not expressed in the ventral retina. Thus, the change that coincides with the evolution of unusual anablepid eye morphology is the loss of rh2-1 expression in the dorsal retina, probably to accommodate increased lws opsin expression. The retinal area that samples aerial light appears not to have changed with respect to photoreceptor transcription. PMID:21775314

Owens, Gregory L; Rennison, Diana J; Allison, W Ted; Taylor, John S

2012-02-23

24

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

PubMed Central

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

2011-01-01

25

A novel and ancient vertebrate opsin  

Microsoft Academic Search

We describe the identification of a novel opsin gene isolated from the eyes of Atlantic salmon. The cDNA sequence predicts a protein that has the key features of an opsin, but shows only 32–42% amino acid identity to the known opsin families. Phylogenetic analysis suggests that this opsin is a member of a hitherto unrecognised opsin family that diverged early

Bobby G Soni; Russell G Foster

1997-01-01

26

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

PubMed

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

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

2012-11-01

27

Catalogue of ISO LWS observations of asteroids  

Microsoft Academic Search

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 mum, and are a unique dataset for future investigations and detailed characterisations of these bodies. Aims: The standard

Felix Hormuth; T. G. Müller

2009-01-01

28

Transcriptional co-regulation of evolutionarily conserved microRNA/cone opsin gene pairs: Implications for photoreceptor subtype specification.  

PubMed

The vertebrate retina contains two types of photoreceptor cells, rods and cones, which use distinct types of opsins and phototransduction proteins. Cones can be further divided into several subtypes with differing wavelength sensitivity and morphology. Although photoreceptor development has been extensively studied in a variety of vertebrate species, the mechanism by which photoreceptor subtypes are established is still largely unknown. Here we report two microRNAs (miRNAs), miR-726 and miR-729, which are potentially involved in photoreceptor subtype specification. In the medaka Oryzias latipes, the genes encoding miR-726 and miR-729 are located upstream of the red-sensitive opsin gene LWS-A and the UV-sensitive opsin gene SWS1, respectively, and are transcribed in the opposite direction from the respective opsin genes. The miR-726/LWS pair is conserved between teleosts and tetrapods, and the miR-729/SWS1 pair is conserved among teleosts. in situ hybridization analyses and fluorescence reporter assays suggest that these miRNAs are co-expressed with the respective opsins in specific cone subtypes. Potential targets of miR-726 and miR-729 predicted in silico include several transcription factors that regulate photoreceptor development. Functional analyses of cis-regulatory sequences in vivo suggest that transcription of the paired microRNA and opsin genes is co-regulated by common cis-regulatory modules. We propose an evolutionarily conserved mechanism that controls photoreceptor subtype identity through coupling between transcriptional and post-transcriptional regulations. PMID:24797636

Daido, Yutaka; Hamanishi, Sakurako; Kusakabe, Takehiro G

2014-08-01

29

The LWS TR&T Program  

NASA Astrophysics Data System (ADS)

NASA's Living With a Star (LWS) Targetted Research and Technology (TR&T) program focuses on space science research areas with the potential for societal impact, e.g. forecasting variations in the solar EUV radiation and corresponding ionospheric effects, coronal mass ejections and corresponding geomagnetic and auroral activity, ionospheric radio propagation, variations in radiation belt particle intensity, and the influence of space weather upon the Earth's climate. Examples of LWS-funded research projects in each area will be given. With the guidance of an initial Science Definition Team and an ongoing Steering Committee with rotating membership, the TR&T program will set research objectives, encourage cross-disciplinary research and end-to-end modeling efforts, and define the metrics needed to evaluate these efforts. The program will provide a publically-accessible WWW site to host tools and data sets developed by the program, and may institute a series of workshops.

Sibeck, D.

30

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

31

Three cone opsin genes determine the properties of the visual spectra in the Japanese anchovy, Engraulis japonicus (Engraulidae, Teleostei).  

PubMed

A complement of cone visual pigments was identified in the Japanese anchovy Engraulis japonicus, one of the engraulid fish species that has a retina specialized for polarization and color vision. The nature of the chromophore bound to opsin proteins was investigated using high performance liquid chromatography. The opsin genes were then cloned and sequenced, and the absorption spectra of different types of cones were obtained by microspectrophotometry. Two green (EJ-RH2-1, EJ-RH2-2) and one red (EJ-LWS) cone opsin genes were identified and are presumably related to the vitamin A1-based visual pigments (i.e. rhodopsins) with ?max values of 492, 474 and 512 nm, respectively. The long and short cones from the ventro-temporal retinal zone consisted of a pure population of RH2 class gene-based pigments (?max=492 nm). The long and short cones from other retinal areas and the lateral components of the triple cones possessed a mixture of RH2 and LWS class gene-based pigments that exhibited a ?max of ~502 nm. The central component of the triple cones contained only RH2 class gene-based pigments (?max=474 nm). Thus, E. japonicus possesses a middle-wave range of spectral sensitivity and acquires different color vision systems in distinct visual fields. PMID:23197087

Kondrashev, Sergei L; Miyazaki, Taeko; Lamash, Nina E; Tsuchiya, Tohru

2013-03-15

32

Phylogeny and physiology of Drosophila opsins  

Microsoft Academic Search

Phylogenetic and physiological methods were used to study the evolution of the opsin gene family in Drosophila. A phylogeny based on DNA sequences from 13 opsin genes including representatives from the two major subgenera of Drosophila shows six major, well-supported clades: The “blue opsin” clade includes all of the Rhl and Rh2 genes and is separated into two distinct subclades

John P. Carulli; De-Mao Chen; William S. Stark; Daniel L. Hartl

1994-01-01

33

BiP prevents rod opsin aggregation  

PubMed Central

Mutations in rod opsin—the light-sensitive protein of rod cells—cause retinitis pigmentosa. Many rod opsin mutations lead to protein misfolding, and therefore it is important to understand the role of molecular chaperones in rod opsin biogenesis. We show that BiP (HSPA5) prevents the aggregation of rod opsin. Cleavage of BiP with the subtilase cytotoxin SubAB results in endoplasmic reticulum (ER) retention and ubiquitylation of wild-type (WT) rod opsin (WT–green fluorescent protein [GFP]) at the ER. Fluorescence recovery after photobleaching reveals that WT-GFP is usually mobile in the ER. By contrast, depletion of BiP activity by treatment with SubAB or coexpression of a BiP ATPase mutant, BiP(T37G), decreases WT-GFP mobility to below that of the misfolding P23H mutant of rod opsin (P23H-GFP), which is retained in the ER and can form cytoplasmic ubiquitylated inclusions. SubAB treatment of P23H-GFP–expressing cells decreases the mobility of the mutant protein further and leads to ubiquitylation throughout the ER. Of interest, BiP overexpression increases the mobility of P23H-GFP, suggesting that it can reduce mutant rod opsin aggregation. Therefore inhibition of BiP function results in aggregation of rod opsin in the ER, which suggests that BiP is important for maintaining the solubility of rod opsin in the ER.

Athanasiou, Dimitra; Kosmaoglou, Maria; Kanuga, Naheed; Novoselov, Sergey S.; Paton, Adrienne W.; Paton, James C.; Chapple, J. Paul; Cheetham, Michael E.

2012-01-01

34

Shedding new light on opsin evolution.  

PubMed

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

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

2012-01-01

35

ISO-LWS Spectroscopy of Centaurus A: Extended Star Formation.  

National Technical Information Service (NTIS)

We present the first full FIR spectrum of Centaurus A (NGC 5128) from 43 - 196.7 micrometers. The data was obtained with the ISO Long Wavelength Spectrometer (LWS). We conclude that the FIR emission in a 70' beam centred on the nucleus is dominated by sta...

G. J. Stacey J. Fisher P. Cox P. E. Clegg S. J. Unger

2000-01-01

36

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

37

Metazoan opsin evolution reveals a simple route to animal vision  

PubMed Central

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

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

2012-01-01

38

Metazoan opsin evolution reveals a simple route to animal vision.  

PubMed

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

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

2012-11-13

39

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

2013-07-01

40

Paralogous origin of the rhodopsinlike opsin genes in lizards  

Microsoft Academic Search

Rhodopsinlike opsins constitute a distinct phylogenetic group (Yokoyama 1994, Mol. Biol. Evol. 11:32–39). This RH2 group includes the green-sensitive opsins in chicken and goldfish and the blue-sensitive opsin in a nocturnal lizard gecko. In the present study, we isolated and sequenced the genomic DNA clones for the RH2 opsin gene, rh2Ac, of the diurnal lizard Anolis carolinensis. This single-copy gene

Shoji Kawamura; Shozo Yokoyama

1995-01-01

41

Variable Rates of Evolution Among Drosophila Opsin Genes  

Microsoft Academic Search

DNA sequences and chromosomal locations of four Drosophila pseudoobscura opsin genes were compared with those from Drosophila melanogaster, to determine factors that influence the evolution of multigene families. Although the opsin proteins perform the same primary functions, the compar- isons reveal a wide range of evolutionary rates. Amino acid identities for the opsins range from 90% for Rh2 to more

John P. Carulli; Daniel L. Hart

1992-01-01

42

Losses of functional opsin genes, short-wavelength cone photopigments, and color vision--a significant trend in the evolution of mammalian vision.  

PubMed

All mammalian cone photopigments are derived from the operation of representatives from two opsin gene families (SWS1 and LWS in marsupial and eutherian mammals; SWS2 and LWS in monotremes), a process that produces cone pigments with respective peak sensitivities in the short and middle-to-long wavelengths. With the exception of a number of primate taxa, the modal pattern for mammals is to have two types of cone photopigment, one drawn from each of the gene families. In recent years, it has been discovered that the SWS1 opsin genes of a widely divergent collection of eutherian mammals have accumulated mutational changes that render them nonfunctional. This alteration reduces the retinal complements of these species to a single cone type, thus rendering ordinary color vision impossible. At present, several dozen species from five mammalian orders have been identified as falling into this category, but the total number of mammalian species that have lost short-wavelength cones in this way is certain to be much larger, perhaps reaching as high as 10% of all species. A number of circumstances that might be used to explain this widespread cone loss can be identified. Among these, the single consistent fact is that the species so affected are nocturnal or, if they are not technically nocturnal, they at least feature retinal organizations that are typically associated with that lifestyle. At the same time, however, there are many nocturnal mammals that retain functional short-wavelength cones. Nocturnality thus appears to set the stage for loss of functional SWS1 opsin genes in mammals, but it cannot be the sole circumstance. PMID:23286388

Jacobs, Gerald H

2013-03-01

43

Type II Opsins: Evolutionary Origin by Internal Domain Duplication?  

Microsoft Academic Search

Opsins are a large group of proteins with seven transmembrane segments (TMSs) that are found in all domains of life. There\\u000a are two types of opsins that are sometimes considered nonhomologous: type I is known from prokaryotes and some eukaryotes,\\u000a while type II is known only from Eumetazoan animals. Type II opsins are members of the family of G-protein coupled

Nicholas D. Larusso; Brian E. Ruttenberg; Ambuj K. Singh; Todd H. Oakley

2008-01-01

44

Bacterio-Opsin Mutants of Halobacterium halobium  

Microsoft Academic Search

The bacterio-opsin (bop) gene of Halobacterium halobium R1 has been cloned with about 40 kilobases of flanking genomic sequence. The 40-kilobase segment is derived from the (G+C)-rich fraction of the chromosome and is not homologous to the major (pHH1) or minor endogenous covalently closed circular DNA species of H. halobium. A 5.1-kilobase Pst I fragment containing the bop gene was

Mary Betlach; Felicitas Pfeifer; James Friedman; Herbert W. Boyer

1983-01-01

45

Genetic Basis of Differential Opsin Gene Expression in Cichlid Fishes  

PubMed Central

Visual sensitivity can be tuned by differential expression of opsin genes. Among African cichlid fishes, seven cone opsin genes are expressed in different combinations to produce diverse visual sensitivities. To determine the genetic architecture controlling these adaptive differences, we analyzed genetic crosses between species expressing different complements of opsin genes. Quantitative genetic analyses suggest that expression is controlled by only a few loci with correlations among some genes. Genetic mapping identifies clear evidence of trans-acting factors in two chromosomal regions that contribute to differences in opsin expression as well as one cis-regulatory region. Therefore, both cis and trans regulation are important. The simple genetic architecture suggested by these results may explain why opsin gene expression is evolutionarily labile, and why similar patterns of expression have evolved repeatedly in different lineages.

Carleton, Karen L; Hofmann, Christopher M; Klisz, Christie; Patel, Zil; Chircus, Lauren M; Simenauer, Lauren H; Soodoo, Natasha; Albertson, R Craig; Ser, Jennifer R

2010-01-01

46

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 in the visual\\/irradiance detection cycle. The majority of the opsins, such as rod and cone opsins, have a very highly conserved gene structure suggesting a common lineage. Exceptions to this are RGR-opsin and melanopsin, whose genes have very different intron insertion positions. The

James Bellingham; Dominic J Wells; Russell G Foster

2003-01-01

47

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

48

Cloning and characterization of the pineal gland-specific opsin gene of marine lamprey ( Petromyzon marinus)  

Microsoft Academic Search

We have cloned and sequenced the pineal gland-specific opsin (P opsin) gene, pPm, of marine lamprey, P. marinus. The deduced P opsin, PPm, consisting of 444aa, is about 90aa longer than the orthologous opsins of chicken, pigeon, and American chameleon. The evolution of PPm is characterized not only by a significantly higher rate ofaa replacement than the other P opsins

Shozo Yokoyama; Huan Zhang

1997-01-01

49

Opsin gene duplication and divergence in ray-finned fish.  

PubMed

Opsin gene sequences were first reported in the 1980s. The goal of that research was to test the hypothesis that human opsins were members of a single gene family and that variation in human color vision was mediated by mutations in these genes. While the new data supported both hypotheses, the greatest contribution of this work was, arguably, that it provided the data necessary for PCR-based surveys in a diversity of other species. Such studies, and recent whole genome sequencing projects, have uncovered exceptionally large opsin gene repertoires in ray-finned fishes (taxon, Actinopterygii). Guppies and zebrafish, for example, have 10 visual opsin genes each. Here we review the duplication and divergence events that have generated these gene collections. Phylogenetic analyses revealed that large opsin gene repertories in fish have been generated by gene duplication and divergence events that span the age of the ray-finned fishes. Data from whole genome sequencing projects and from large-insert clones show that tandem duplication is the primary mode of opsin gene family expansion in fishes. In some instances gene conversion between tandem duplicates has obscured evolutionary relationships among genes and generated unique key-site haplotypes. We mapped amino acid substitutions at so-called key-sites onto phylogenies and this exposed many examples of convergence. We found that dN/dS values were higher on the branches of our trees that followed gene duplication than on branches that followed speciation events, suggesting that duplication relaxes constraints on opsin sequence evolution. Though the focus of the review is opsin sequence evolution, we also note that there are few clear connections between opsin gene repertoires and variation in spectral environment, morphological traits, or life history traits. PMID:22178363

Rennison, Diana J; Owens, Gregory L; Taylor, John S

2012-03-01

50

Carrier Plus: a sensor payload for Living With a Star space environment testbed (LWS/SET)  

NASA Astrophysics Data System (ADS)

The Defense Threat Reduction Agency (DTRA) and National Aeronautics and Space Administration (NASA) Goddard Space Flight Center are collaborating to develop the Carrier Plus sensor experiment platform as a capability of the Space Environment Testbed (SET). The Space Environment Testbed (SET) provides flight opportunities for technology experiments as part of NASA's Living With a Star (LWS) program. The Carrier Plus will provide new capability to characterize sensor technologies such as state-of-the-art visible focal plane arrays (FPAs) in a natural space radiation environment. The technical objectives include on-orbit validation of recently developed FPA technologies and sensor performance prediction methodologies, as well as characterization of the FPA radiation response to total ionizing dose damage, displacement damage and transients. It is expected that the sensor experiment will carry 4-6 FPAs and associated radiation correlative environment monitors (CEMs) for a 2008 launch. Sensor technology candidates may include n- and p-charge coupled devices (CCDs), active pixel sensors (APS), and hybrid CMOS arrays. This paper will describe the Carrier Plus goals and objectives, as well as provide details about the architecture and design. More information on the LWS program can be found at http://lws.gsfc.nasa.gov/ gov/. Business announcements for LWS/SET and program briefings are posted at http://lws-set.gsfc.nasa.gov.

Marshall, Cheryl J.; Moss, Steven C.; Howard, Regan E.; LaBel, Kenneth A.; Grycewicz, Thomas J.; Barth, Janet L.; Brewer, Dana

2004-01-01

51

Carrier Plus: A sensor payload for Living With a Star Space Environment Testbed (LWS/SET)  

NASA Technical Reports Server (NTRS)

The Defense Threat Reduction Agency (DTR4) and National Aeronautics and Space Administration (NASA) Goddard Space Flight Center are collaborating to develop the Carrier Plus sensor experiment platform as a capability of the Space Environments Testbed (SET). The Space Environment Testbed (SET) provides flight opportunities for technology experiments as part of NASA's Living With a Star (LWS) program. The Carrier Plus will provide new capability to characterize sensor technologies such as state-of-the-art visible focal plane arrays (FPAs) in a natural space radiation environment. The technical objectives include on-orbit validation of recently developed FPA technologies and performance prediction methodologies, as well as characterization of the FPA radiation response to total ionizing dose damage, displacement damage and transients. It is expected that the sensor experiment will carry 4-6 FPAs and associated radiation correlative environment monitors (CEMs) for a 2006-2007 launch. Sensor technology candidates may include n- and p-charge coupled devices (CCDs), active pixel sensors (APS), and hybrid CMOS arrays. The presentation will describe the Carrier Plus goals and objectives, as well as provide details about the architecture and design. More information on the LWS program can be found at http://lws.gsfc.nasa.gov/. Business announcements for LWS/SET and program briefings are posted at http://lws-set.gsfc.nasa.gov

Marshall, Cheryl J.; Moss, Steven; Howard, Regan; LaBel, Kenneth A.; Grycewicz, Tom; Barth, Janet L.; Brewer, Dana

2003-01-01

52

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

NASA Technical Reports Server (NTRS)

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

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

2004-01-01

53

The Origins of Novel Protein Interactions during Animal Opsin Evolution  

Microsoft Academic Search

BackgroundBiologists 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 FindingsHere 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

David C. Plachetzki; Bernard M. Degnan; Todd H. Oakley; Berend Snel

2007-01-01

54

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

55

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

PubMed

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. PMID:20639420

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

2010-08-01

56

Carrier Plus: a sensor payload for Living With a Star Space Environment Testbed (LWS\\/SET)  

Microsoft Academic Search

The Defense Threat Reduction Agency (DTRA) and National Aeronautics and Space Administration (NASA) Goddard Space Flight Center are collaborating to develop the Carrier Plus sensor experiment platform as a capability of the Space Environment Testbed (SET). The Space Environment Testbed (SET) provides flight opportunities for technology experiments as part of NASA's Living With a Star (LWS) program. The Carrier Plus

Cheryl J. Marshall; Steven Moss; Regan Howard; Kenneth A. LaBel; Tom Grycewicz; Janet L. Barth; Dana Brewer

2008-01-01

57

Carrier Plus: a sensor payload for Living With a Star space environment testbed (LWS\\/SET)  

Microsoft Academic Search

The Defense Threat Reduction Agency (DTRA) and National Aeronautics and Space Administration (NASA) Goddard Space Flight Center are collaborating to develop the Carrier Plus sensor experiment platform as a capability of the Space Environment Testbed (SET). The Space Environment Testbed (SET) provides flight opportunities for technology experiments as part of NASA's Living With a Star (LWS) program. The Carrier Plus

Cheryl J. Marshall; Steven C. Moss; Regan E. Howard; Kenneth A. LaBel; Thomas J. Grycewicz; Janet L. Barth; Dana Brewer

2004-01-01

58

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

Microsoft Academic Search

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

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

2000-01-01

59

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

NASA Technical Reports Server (NTRS)

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

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

1997-01-01

60

Sequences and Evolution of Human and Squirrel Monkey Blue Opsin Genes  

Microsoft Academic Search

.   The sequences of the entire blue opsin gene in the squirrel monkey (Saimiri boliviensis) and the five introns of the human blue opsin gene were obtained. Intron 3 of these genes contains an Alu sequence and intron\\u000a 4 contains a partial mer13 sequence. A comparison of the squirrel monkey opsin sequence with published mammalian opsin sequences\\u000a shows that features

Lawrence C. Shimmin; Phuong Mai; Wen-Hsiung Li

1997-01-01

61

Evolutionary analysis of opsin genes in Tribolium and related darkling beetles  

Microsoft Academic Search

Color vision is highly conserved in insects including beetles (Coleoptera), facilitated by the differential expression of opsin genes. We searched for UV-, B- and LW-opsins and investigated their expression in three new darkling species: Tribolium confusum, Tenebrio molitor, Zophobas atratus. Single UV- and LW-opsin paralogs were cloned from each species. Any attempts of cloning an ortholog of the B-opsin subfamily

Meng Wu

2008-01-01

62

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

63

Evolutionary dynamics of rhodopsin type 2 opsins in vertebrates.  

PubMed

Among the five groups of visual pigments in vertebrates, the rhodopsin type 2 (RH2) group shows the largest number of gene duplication events. We have isolated three intact and one nonfunctional RH2 opsin genes each from Northern lampfish (Stenobrachius leucopsarus) and scabbardfish (Lepidopus fitchi). Using the deduced amino acid sequences of these and other representative RH2 opsin genes in vertebrates, we have estimated the divergence times and evolutionary rates of amino acid substitution at various stages of RH2 opsin evolution. The results show that the duplications of the lampfish and scabbardfish RH2 opsins have occurred approximately 60 and approximately 30 million years ago (Ma), respectively. The evolutionary rates of RH2 opsins in the early vertebrate ancestors were approximately 0.25 x 10(-9)/site/year, which increased to approximately 1 x 10(-9) to 3 x 10(-9)/site/year in euteleost lineages and to approximately 0.3 x 10(-9) to 0.5 x 10(-9)/site/year in coelacanth and tetrapods. PMID:19759234

Yokoyama, Shozo; Tada, Takashi

2010-01-01

64

The evolution and expression of the moth visual opsin family.  

PubMed

Because visual genes likely evolved in response to their ambient photic environment, the dichotomy between closely related nocturnal moths and diurnal butterflies forms an ideal basis for investigating their evolution. To investigate whether the visual genes of moths are associated with nocturnal dim-light environments or not, we cloned long-wavelength (R), blue (B) and ultraviolet (UV) opsin genes from 12 species of wild-captured moths and examined their evolutionary functions. Strong purifying selection appeared to constrain the functions of the genes. Dark-treatment altered the levels of mRNA expression in Helicoverpa armigera such that R and UV opsins were up-regulated after dark-treatment, the latter faster than the former. In contrast, B opsins were not significantly up-regulated. Diel changes of opsin mRNA levels in both wild-captured and lab-reared individuals showed no significant fluctuation within the same group. However, the former group had significantly elevated levels of expression compared with the latter. Consequently, environmental conditions appeared to affect the patterns of expression. These findings and the proportional expression of opsins suggested that moths potentially possessed color vision and the visual system played a more important role in the ecology of moths than previously appreciated. This aspect did not differ much from that of diurnal butterflies. PMID:24205129

Xu, Pengjun; Lu, Bin; Xiao, Haijun; Fu, Xiaowei; Murphy, Robert W; Wu, Kongming

2013-01-01

65

Characterization of Changes in Megalagrion Opsin Genes to Detect Signatures of Selection  

Microsoft Academic Search

Megalagrion damselflies have radiated into new breeding habitats independently at least six times in the Hawaiian archipelago, and have evolved bright body coloration numerous times. We hypothesize that these radiations are correlated with specific changes in the opsin proteins. We isolated and characterized two opsin genes from nine different Megalagrion species. The opsin phylogeny is consistent with the phylogeny based

Bhagya G Janananda

2011-01-01

66

Cloning and Characterization of Rod Opsin cDNA From the Old World Monkey, Macaca fascicularis  

Microsoft Academic Search

Purpose. Opsin sequences from different phyla have been compared to examine the structural and functional regions of this molecule and to assess the molecular evolution of genes in the animal kingdom. Of all the sequences reported, there is only one primate sequence (human) for rod opsin. To extend our knowledge of the primate family of opsins, the authors cloned and

Robert W. Nickells; Claude F. Burgoyne; Harry A. Quigley; Donald J. Zack

67

Early Duplication and Functional Diversification of the Opsin Gene Family in Insects  

Microsoft Academic Search

Recent analysis of the complete mosquito Anopheles gambiae genome has revealed a far higher number of opsin genes than for either the Drosophila melanogaster genome or any other known insect. In particular, the analysis revealed an extraordinary opsin gene content expansion, whereby half are long wavelength-sensitive (LW) opsin gene duplicates. We analyzed this genomic data in relationship to other known

Johannes Spaethe; Adriana D. Briscoe

2004-01-01

68

Parallel evolution of opsin gene expression in African cichlid fishes.  

PubMed

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

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

2010-12-01

69

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

70

Characterisation and localisation of the opsin protein repertoire in the brain and retinas of a spider and an onychophoran  

PubMed Central

Background Opsins have been found in the majority of animals and their most apparent functions are related to vision and light-guided behaviour. As an increasing number of sequences have become available it has become clear that many opsin-like transcripts are expressed in tissues other than the eyes. Opsins can be divided into three main groups: rhabdomeric opsins (r-opsins), ciliary opsins (c-opsins) and group 4 opsins. In arthropods, the main focus has been on the r-opsins involved in vision. However, with increased sequencing it is becoming clear that arthropods also possess opsins of the c-type, group 4 opsins and the newly discovered arthropsins but the functions of these opsins are unknown in arthropods and data on their localisation is limited or absent. Results We identified opsins from the spider Cupiennius salei and the onychophoran Euperipatoides kanangrensis and characterised the phylogeny and localisation of these transcripts. We recovered all known visual opsins in C. salei, and in addition found a peropsin, a c-opsin and an opsin resembling Daphnia pulex arthropsin. The peropsin was expressed in all eye types except the anterior median eyes. The arthropsin and the c-opsin were expressed in the central nervous system but not the eyes. In E. kanangrensis we found: a c-opsin; an opsin resembling D. pulex arthropsins; and an r-opsin with high sequence similarity to previously published onychophoran onychopsins. The E. kanangrensis c-opsin and onychopsin were expressed in both the eyes and the brain but the arthropsin only in the brain. Conclusion Our novel finding that opsins of both the ciliary and rhabdomeric type are present in the onychophoran and a spider suggests that these two types of opsins were present in the last common ancestor of the Onychophora and Euarthropoda. The expression of the c-opsin in the eye of an onychophoran indicates that c-opsins may originally have been involved in vision in the arthropod clade. The lack of c-opsin expression in the spider retina suggests that the role for c-opsin in vision was lost in the euarthropods. Our discovery of arthropsin in onychophorans and spiders dates the emergence of arthropsin to the common ancestor of Onychophora and Euarthropoda and their expression in the brain suggests a non-visual function.

2013-01-01

71

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

2013-07-01

72

Vertebrate ancient opsin photopigment spectra and the avian photoperiodic response  

PubMed Central

In mammals, photoreception is restricted to cones, rods and a subset of retinal ganglion cells. By contrast, non-mammalian vertebrates possess many extraocular photoreceptors but in many cases the role of these photoreceptors and their underlying photopigments is unknown. In birds, deep brain photoreceptors have been shown to sense photic changes in daylength (photoperiod) and mediate seasonal reproduction. Nonetheless, the specific identity of the opsin photopigment ‘sensor’ involved has remained elusive. Previously, we showed that vertebrate ancient (VA) opsin is expressed in avian hypothalamic neurons and forms a photosensitive molecule. However, a direct functional link between VA opsin and the regulation of seasonal biology was absent. Here, we report the in vivo and in vitro absorption spectra (?max = ?490 nm) for chicken VA photopigments. Furthermore, the spectral sensitivity of these photopigments match the peak absorbance of the avian photoperiodic response (?max = 492 nm) and permits maximum photon capture within the restricted light environment of the hypothalamus. Such a correspondence argues strongly that VA opsin plays a key role in regulating seasonal reproduction in birds.

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

2012-01-01

73

Diversity of animal opsin-based pigments and their optogenetic potential.  

PubMed

Most animal opsin-based pigments are typical G protein-coupled receptors (GPCR) and consist of a protein moiety, opsin, and 11-cis retinal as a chromophore. More than several thousand opsins have been identified from a wide variety of animals, which have multiple opsin genes. Accumulated evidence reveals the molecular property of opsin-based pigments, particularly non-conventional visual pigments including non-visual pigments. Opsin-based pigments are generally a bistable pigment having two stable and photointerconvertible states and therefore are bleach-resistant and reusable, unlike vertebrate visual pigments which become bleached. The opsin family contains Gt-coupled, Gq-coupled, Go-coupled, Gs-coupled, Gi-coupled, and Gi/Go-coupled opsins, indicating the existence of a large diversity of light-driven GPCR-signaling cascades. It is suggested that these molecular properties might contribute to different physiologies. In addition, various opsin based-pigments, especially nonconventional visual pigments having different molecular characteristics would facilitate the design and development of promising optogenetic tools for modulating GPCR-signaling, which is involved in a wide variety of physiological responses. We here introduce molecular and functional properties of various kinds of opsins and discuss their physiological function and also their potentials for optogenetic applications. This article is part of a Special Issue entitled: Retinal proteins - you can teach an old dog new tricks. PMID:24041647

Koyanagi, Mitsumasa; Terakita, Akihisa

2014-05-01

74

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

Microsoft Academic Search

Although previous investigations have shown that wing coloration is an important component of social signaling in butterflies, the contribution of opsin evolution to sexual wing color dichromatism and interspecific divergence remains largely unexplored. Here we report that the butterfly Lycaena rubidus has evolved sexually dimorphic eyes due to changes in the regulation of opsin expression patterns to match the contrasting

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

2006-01-01

75

Explant cultures of Rpe65?/? mouse retina: a model to investigate cone opsin trafficking  

PubMed Central

Purpose In the absence of 11-cis retinal (e.g., Rpe65?/?), the chromophore for all pigments, cone opsins are mislocalized in vivo. Using the systemic application of 11-cis retinal, appropriate protein localization can be promoted. Here, we asked whether explant cultures of Rpe65?/? mouse retina are amenable to screening retinoids for their ability to promote opsin trafficking. Methods Retina-retinal pigment epithelium (RPE) cultures were prepared from 7-day-old Rpe65?/? Rho?/? or wild-type pups and cultured for 11 days. Explants were treated with retinoids throughout this period. Ultraviolet (UV)-opsin trafficking was analyzed by immunohistochemistry and quantitative image analysis, while its messenger RNA expression was examined by quantitative real-time PCR, and the interaction of retinoids with UV-opsin was probed in transducing-activation assays. Results In wild-type explant cultures, UV-opsin was restricted to the outer segments, whereas in those derived from Rpe65?/? Rho?/? mice, opsin trafficking was impaired. In Rpe65?/? Rho?/? explants, administration of 11-cis retinal, 11-cis retinol or retinoic acid (RA) reversed the opsin trafficking phenotype. RA analogs designed to act by binding to the retinoic acid receptor or the retinoid X-receptor, however, had no effect. RA was shown to interact with the UV–cone opsin, demonstrated by its ability to effect ligand-dependent activation of transducin by UV–cone opsin. All compounds tested increased cone opsin messenger RNA expression. Conclusions Cone-opsin trafficking defects were replicated in Rpe65?/? Rho?/? retina-RPE cultures, and were reversed by 11-cis retinal treatment. Comparing the effects of different retinoids on their ability to promote UV-opsin trafficking to outer segments confirmed the critical role of agents that bind in the retinoid binding pocket. Retinoids that act as transcription factors, however, were ineffective. Thus, organ cultures may be a powerful low-throughput screening tool to identify novel compounds to promote cone survival.

Bandyopadhyay, Mausumi; Kono, Masahiro

2013-01-01

76

Pteropsin: A vertebrate-like non-visual opsin expressed in the honey bee brain  

Microsoft Academic Search

Insects have excellent color vision based on the expression of different opsins in specific sets of photoreceptive cells. Opsins are members of the rhodopsin superfamily of G-protein coupled receptors, and are transmembrane proteins found coupled to light-sensitive chromophores in animal photoreceptors. Diversification of opsins during animal evolution provided the basis for the development of wavelength-specific behavior and color vision, but

Rodrigo A. Velarde; Colin D. Sauer; Kimberly K. O. Walden; Susan E. Fahrbach; Hugh M. Robertson

2005-01-01

77

Frequent gene conversion between human red and green opsin genes  

Microsoft Academic Search

To study the evolution of human X-linked red and green opsin genes, genomic sequences in large regions of the two genes were\\u000a compared. The divergences in introns 3, 4, and 5 and the 3? flanking sequence of the two genes are significantly lower than\\u000a those in exons 4 and 5. The homogenization mechanism of introns and the 3? flanking sequence

Zhongming Zhao; David Hewett-Emmett; Wen-Hsiung Li

1998-01-01

78

The Opsin Shift and Mechanism of Spectral Tuning of Rhodopsin  

PubMed Central

Molecular dynamics simulations and combined quantum mechanical and molecular mechanical (QM/MM) calculations have been performed to investigate the mechanism of the opsin shift and spectral tuning in rhodopsin. A red shift of ?980 cm?1 was estimated in the transfer of the chromophore from methanol solution environment to the protonated Schiff base binding site of the opsin. The conformational change from a 6-s-cis-all-trans configuration in solution to the 6-s-cis-11-cis conformer contributes additional ?200 cm?1 and the remaining effects were attributed to dispersion interactions with the aromatic residues in the binding site. An opsin shift of 2100 cm?1 was obtained, in reasonable accord with experiment (2730 cm?1). Dynamics simulations revealed that the 6-s-cis bond can occupy two main conformations for the ?-ionone ring, resulting a weighted average dihedral angle of about 50°, which may be compared with the experimental estimate of ?28° from solid-state NMR and Raman data. We investigated a series of four single-mutations, including E113D, A292S, T118A and A269T, which are located near the protonated Schiff base, along the polyene chain of retinal and close to the ionone ring. The computational results on absorption energy shift provided insights into the mechanism of spectral tuning, which involves all means of electronic structural effects, including the stabilization or destabilization of either the ground or the electronically excited state of the retinal protonated Schiff base.

Rajamani, Ramkumar; Lin, Yen-lin

2010-01-01

79

Bacterio-Opsin mRNA in Wild-Type and Bacterio-Opsin-Deficient Halobacterium halobium Strains  

Microsoft Academic Search

We have examined transcripts corresponding to the Halobacterium halobium bacterio-opsin (BO) gene in wild-type and in BO-deficient mutant strains containing the insertion elements ISH1 or ISH2 in the BO gene. BO mRNA from the wild-type strain was purified by hybrid selection using single-stranded cDNA. Labeling by vaccinia virus capping enzyme and [alpha -32P]GTP showed that it contains the 5'-terminal nucleotide

Shiladitya Dassarma; Uttam L. Rajbhandary; H. Gobind Khorana

1984-01-01

80

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

PubMed

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

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

2009-02-01

81

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

PubMed

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

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

2014-07-01

82

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

83

Opsin Synthesis and mRNA Levels in Dystrophic Retinas Devoid of Outer Segments in Retinal Degeneration Slow (rds) Mice  

Microsoft Academic Search

Opsin gene regulation, as a function of outer segment struc- ture, was studied in normal and mutant retinal degeneration slow (r&r) mice. We investigated the level of expression of the opsin gene in the rds mutant to determine if the reduced opsin content observed in this mutation (around 3% of nor- mal) is a consequence of lowered expression of its

Neeraj Agarwal; David S. Papermaster

1990-01-01

84

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

85

Opsin Phylogeny and Evolution: A Model for Blue Shifts in Wavelength Regulation  

Microsoft Academic Search

The vast diversity in spectral sensitivities in the vision of many organisms is mediated mostly (although not entirely) through variation in the photosensitive visual pigments (opsins) of the eye. Specifically, shifts in absorption maxima of visual pigments are thought to be a result of interactions within the binding pocket of the opsin, between amino acid side chains and the retinal

Belinda S. W. Chang; Keith A. Crandall; John P. Carulli; Daniel L. Hartl

1995-01-01

86

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

87

Adaptive Molecular Evolution in the Opsin Genes of Rapidly Speciating Cichlid Species  

Microsoft Academic Search

Cichlid fish inhabit a diverse range of environments that vary in the spectral content of light available for vision. These differences should result in adaptive selective pressure on the genes involved in visual sensitivity, the opsin genes. This study examines the evidence for differential adaptive molecular evolution in East African cichlid opsin genes due to gross differences in environmental light

Tyrone C. Spady; Ole Seehausen; Ellis R. Loew; Rebecca C. Jordan; Thomas D. Kocher; Karen L. Carleton

2005-01-01

88

Cone Opsin Genes of African Cichlid Fishes: Tuning Spectral Sensitivity by Differential Gene Expression  

Microsoft Academic Search

Spectral tuning of visual pigments is typically accomplished through changes in opsin amino acid sequence. Within a given opsin class, changes at a few key sites control wavelength specificity. To investigate known differences in the visual pigment spectral sensitivity of the Lake Malawi cichlids, Metriaclima zebra (368, 488, and 533 nm) and Dimidiochromis compressiceps(447, 536, and 569 nm), we sequenced

Karen L. Carleton; Thomas D. Kocher

89

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

Microsoft Academic Search

The evolution of cone opsin genes is characterized by a dynamic process of gene birth and death through gene duplication and loss. However, the forces governing the retention and death of opsin genes are poorly understood. African cichlid fishes have a range of ecologies, differing in habitat and foraging style, which make them ideal for examining the selective forcesacting ontheopsin

Tyrone C. Spady; Juliet W. L. Parry; Phyllis R. Robinson; David M. Hunt; James K. Bowmaker; Karen L. Carleton

2006-01-01

90

Molecular evolution of a long wavelength-sensitive opsin in mimetic Heliconius butterflies (Lepidoptera: Nymphalidae)  

Microsoft Academic Search

This study examines the pattern of opsin nucleotide and amino acid substitution among mimetic species «rings» of Heliconius butterflies that are characterized by divergent wing colour patterns. A long wavelength opsin gene, OPS1, was sequenced from each of seven species of Heliconius and one species of Dryas (Lepidoptera: Nymphalidae). A parsimony analysis of OPS1 nucleotide and amino acid sequences resulted

RUBY HSU; ADRIANA D. BRISCOE; BELINDA S. W. CHANG; NAOMI E. PIERCE

2001-01-01

91

Ocular and Extraocular Expression of Opsins in the Rhopalium of Tripedalia cystophora (Cnidaria: Cubozoa)  

PubMed Central

A growing body of work on the neuroethology of cubozoans is based largely on the capabilities of the photoreceptive tissues, and it is important to determine the molecular basis of their light sensitivity. The cubozoans rely on 24 special purpose eyes to extract specific information from a complex visual scene to guide their behavior in the habitat. The lens eyes are the most studied photoreceptive structures, and the phototransduction in the photoreceptor cells is based on light sensitive opsin molecules. Opsins are photosensitive transmembrane proteins associated with photoreceptors in eyes, and the amino acid sequence of the opsins determines the spectral properties of the photoreceptors. Here we show that two distinct opsins (Tripedalia cystophora-lens eye expressed opsin and Tripedalia cystophora-neuropil expressed opsin, or Tc-leo and Tc-neo) are expressed in the Tripedalia cystophora rhopalium. Quantitative PCR determined the level of expression of the two opsins, and we found Tc-leo to have a higher amount of expression than Tc-neo. In situ hybridization located Tc-leo expression in the retinal photoreceptors of the lens eyes where the opsin is involved in image formation. Tc-neo is expressed in a confined part of the neuropil and is probably involved in extraocular light sensation, presumably in relation to diurnal activity.

Bielecki, Jan; Zaharoff, Alexander K.; Leung, Nicole Y.; Garm, Anders; Oakley, Todd H.

2014-01-01

92

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

93

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

NASA Technical Reports Server (NTRS)

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

MacNeice, Peter

2012-01-01

94

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

95

Effect of temperature, density, and technical factors on the shock-wave sensitivity of plastic TATB  

Microsoft Academic Search

Results are presented from a study of the shock-wave sensitivity of plastic TATB over a wide range of temperatures. It is\\u000a shown that the temperature dependence of the shock-wave sensitivity of this explosive material is explained to a great extent\\u000a by the change in density owing to thermal expansion, and by relaxation processes that occur in the samples.

Y. A. Vlasov; V. B. Kosolapov; L. V. Fomicheva; I. P. Khabarov

1998-01-01

96

The retinal mosaics of opsin expression in invertebrates and vertebrates  

PubMed Central

Colour vision is found in many invertebrate and vertebrate species. It is the ability to discriminate objects based on the wavelength of emitted light independent of intensity. As it requires the comparison of at least two photoreceptor types with different spectral sensitivities, this process is often mediated by a mosaic made of several photoreceptor types. In this review, we summarize the current knowledge about the formation of retinal mosaics and the regulation of photopigment (opsin) expression in the fly, mouse and human retina. Despite distinct evolutionary origins, as well as major differences in morphology and phototransduction machineries, there are significant similarities in the stepwise cell-fate decisions that lead from progenitor cells to terminally differentiated photoreceptors that express a particular opsin. Common themes include i) the use of binary transcriptional switches that distinguish classes of photoreceptors, ii) the use of gradients of signaling molecules for regional specializations, iii) stochastic choices that pattern the retina and iv) the use of permissive factors with multiple roles in different photoreceptor types.

Rister, Jens; Desplan, Claude

2011-01-01

97

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

98

Evolution and expression plasticity of opsin genes in a fig pollinator, Ceratosolen solmsi.  

PubMed

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

Wang, Bo; Xiao, Jin-Hua; Bian, Sheng-Nan; Niu, Li-Ming; Murphy, Robert W; Huang, Da-Wei

2013-01-01

99

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

2012-10-01

100

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

101

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

Microsoft Academic Search

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

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

2009-01-01

102

Molecular Evolution of Arthropod Color Vision Deduced from Multiple Opsin Genes of Jumping Spiders  

Microsoft Academic Search

Among terrestrial animals, only vertebrates and arthropods possess wavelength-discrimination ability, so-called “color vision”.\\u000a For color vision to exist, multiple opsins which encode visual pigments sensitive to different wavelengths of light are required.\\u000a While the molecular evolution of opsins in vertebrates has been well investigated, that in arthropods remains to be elucidated.\\u000a This is mainly due to poor information about the

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

2008-01-01

103

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

Microsoft Academic Search

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 Go-type Opsins can be assigned to ancient

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

2006-01-01

104

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

2013-07-01

105

Codistribution of S-antigen and opsin in light-adapted retinal rods  

Microsoft Academic Search

The localization of S-antigen in ultra-cryosections of rat retina has been studied and compared with that of opsin by immunoelectron microscopy. Monospecific antisera to both proteins, and Protein A-coated gold particles of two sizes were used for (double) labeling. In the light-adapted retina, S-antigen showed codistribution with opsin in the rod outer segments. S-antigen labeling was diminished in dark-adapted retina.

R. M. Broekhuyse; E. D. Kuhlmann; L. J. M. Leunissen; H. M. Scheur; A. J. Verkleij

1986-01-01

106

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

107

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

108

Dependence of Plastic TATB Shock-Wave Sensitivity on Temperature, Density and Technology Factors  

Microsoft Academic Search

Mixed TATB-based HE is the most perspective because of the manufacture and exploitation safety of its items. At the same time the safety of these explosive, at high temperatures, which take place at emergencies, causes the certain anxiety. Plastic TATB shock-wave sensitivity (SWS) researches has shown that temperature as one of the important factors of external influence is not always

Yu. A. Vlasov; V. B. Kosolapov; L. V. Fomicheva; I. P. Khabarov

1999-01-01

109

Shock-wave sensitivity of a TATB-based plasticized explosive  

Microsoft Academic Search

The results of numerical modelling of experiments on the investigation of shock-wave sensitivity of a TATB-based explosive are presented. A model for the macrokinetics of decomposition of the explosive has been constructed within the framework of a hypothesis of hot spots.

Yu. A. Aminov; A. V. Vershinin; O. V. Kostitsyn; B. G. Loboiko; V. S. Lyubimov; S. N. Lyubyatinskii; G. N. Rykovanov; M. A. Strizhenok

1995-01-01

110

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

111

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

NASA Astrophysics Data System (ADS)

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

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

2002-05-01

112

The circumstellar environment of IRAS 16293-2422. ISO-LWS and SCUBA observations  

NASA Astrophysics Data System (ADS)

We present far-infrared (FIR) continuum observations of the deeply embedded source IRAS 16293-2422 performed with the Long Wavelength Spectrometer (LWS) on-board the Infrared Space Observatory (ISO). We also report 450 and 850 ?m mapping observations done with the Submillimetre Common-User Bolometer Array (SCUBA) at the James Clerk Maxwell Telescope (JCMT). We combined these observations with IRAS and other JCMT data available in the literature to construct a complete spectral energy distribution (SED) of the source. A spherically symmetric dusty envelope model was used to reproduce the SED and to characterize the circumstellar matter around the object. We call attention to the fact that when using models such as the one presented here, one needs spatial information about the object to distinguish between different possible fits to the SED. A comparison between the intensity profiles at 450 and 850 ?m obtained from the SCUBA observations and the profiles predicted by the model allowed us to constrain the size of the envelope and its density distribution. The SED and the 850 ?m intensity profile of the source are consistent with a centrally peaked power law dust density distribution of the form ?(r) ? r-p with p = 1.5-2, with a radius Renv = 3000-3250 AU, defining a very compact circumstellar envelope. We estimate a bolometric luminosity Lbol = 36 L?, an envelope mass Menv = 3.4 M?, and a submillimetre to bolometric luminosity ratio Lsubmm/Lbol = 1.9%, confirming that the source shows a submillimetre excess characteristic of Class 0 sources.

Correia, J. C.; Griffin, M.; Saraceno, P.

2004-05-01

113

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

SciTech Connect

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

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

1989-03-21

114

Binding of More Than One Retinoid to Visual Opsins  

PubMed Central

Visual opsins bind 11-cis retinal at an orthosteric site to form rhodopsins but increasing evidence suggests that at least some are capable of binding an additional retinoid(s) at a separate, allosteric site(s). Microspectrophotometric measurements on isolated, dark-adapted, salamander photoreceptors indicated that the truncated retinal analog, ?-ionone, partitioned into the membranes of green-sensitive rods; however, in blue-sensitive rod outer segments, there was an enhanced uptake of four or more ?-ionones per rhodopsin. X-ray crystallography revealed binding of one ?-ionone to bovine green-sensitive rod rhodopsin. Cocrystallization only succeeded with extremely high concentrations of ?-ionone and binding did not alter the structure of rhodopsin from the inactive state. Salamander green-sensitive rod rhodopsin is also expected to bind ?-ionone at sufficiently high concentrations because the binding site is present on its surface. Therefore, both blue- and green-sensitive rod rhodopsins have at least one allosteric binding site for retinoid, but ?-ionone binds to the latter type of rhodopsin with low affinity and low efficacy.

Makino, Clint L.; Riley, Charles K.; Looney, James; Crouch, Rosalie K.; Okada, Tetsuji

2010-01-01

115

Circadian rhythms of behavioral cone sensitivity and long wavelength opsin mRNA expression: a correlation study in zebrafish  

Microsoft Academic Search

Using a behavioral assay based on visually mediated escape responses, we measured long-wavelength-sensitive red cone (LC) sensitivities in zebrafish. In a 24·h period, the zebrafish were least sensitive to red light in the early morning and most sensitive in the late afternoon. To investigate if the fluctuation of behavioral cone sensitivity correlates with opsin gene expression, we measured LC opsin

Ping Li; Shelby Temple; Yan Gao; Theordore J. Haimberger; Craig W. Hawryshyn; Lei Li

2005-01-01

116

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

117

Low-frequency vibrational modes in blue opsin: A computational study  

NASA Astrophysics Data System (ADS)

Vibrational excitations of low-frequency collective modes are essential for functionally important conformational transitions in proteins. We have carried out an analysis of the low-frequency modes in blue opsin based on both normal-mode analysis and molecular dynamics simulations. Power spectra obtained by molecular dynamics agree well with the normal modes. A representative set of low-frequency modes is discussed with the help of vector-field representation. We thus demonstrate that terahertz spectroscopy of low-frequency modes might be relevant for identifying those vibrational degrees of freedom that correlate to known conformational changes in opsins.

Thirumuruganandham, Saravana Prakash; Urbassek, Herbert M.

118

Contributions of rhodopsin, cone opsins, and melanopsin to postreceptoral pathways inferred from natural image statistics  

PubMed Central

Visual neural representation is constrained by the statistical properties of the environment. Prior analysis of cone pigment excitations for natural images revealed three principal components corresponding to the major retinogeniculate pathways identified by anatomical and physiological studies in primates. Here, principal component analyses were conducted on the excitations of rhodopsin, cone opsins, and melanopsin for nine hyperspectral images under 21 natural illuminants. The results suggested that rhodopsin and melanopsin may contribute to the three major retinogeniculate pathways. Rhodopsin and melanopsin may provide additional constraints in natural scene statistics, leading to new components that cannot be revealed by analysis based on cone opsin excitations only.

Barrionuevo, Pablo A.; Cao, Dingcai

2014-01-01

119

Rhodopsin chromophore exchanges among opsin molecules in the dark.  

PubMed

Turnover of rhodopsin chromophore in vertebrate visual cells has been explored by light microscope autoradiography (LMARG) and radiobiochemical techniques. Retinol-binding protein (RBP) was isolated from human serum, its native ligand removed and replaced with [3H]-retinol. After reconstitution, [3H]-retinol-RBP was reassociated with prealbumin (PA), and the protein complex injected intravenously into dark-adapted animals. After selected intervals in the dark, animals were killed, and ocular tissues dissected under infrared illumination. Eyecups from frogs and mice were fixed (4 C) and after in situ reduction of the chromophore-protein linkage of rhodopsin with borane dimethyl amine (BDMA), processed histologically to retain lipids, or alternatively to extract them with chloroform-methanol (C-M), and LMARG performed. Rhodopsin was purified from detergent-solubilized mouse retinas by Concanavalin A (Con A) affinity chromatography and analyzed for radioactivity. Autoradiographic labeling of frog rod outer segments (ROS) was first detectable at 1 day postinjection, increasing over the duration of the experiment. At all times, label was distributed throughout the organelle in a diffuse pattern, although in certain cases a band of silver grains was also evident at the proximal end of the ROS, the site of new membrane assembly. Similar autoradiographic patterns were noted in mouse rods, although the kinetics of labeling differed in certain respects. In biochemical experiments, incorporation of [3H]-retinol into mouse rhodopsin was seen to occur very rapidly (less than 30 min), without an appreciable lag period. We interpret the diffuse labeling of ROS to result from an exchange in the dark of [3H]-vitamin A aldehyde for unlabeled opsin-bound chromophore, whereas the formation of a reaction band no doubt reflects the continual renewal of ROS membrane occurring in the dark. With respect to the former, the turnover of chromophore qualitatively resembles that found for membrane fatty acids. PMID:6224755

Defoe, D M; Bok, D

1983-09-01

120

The Major Opsin in Bees (Insecta: Hymenoptera): A Promising Nuclear Gene for Higher Level Phylogenetics  

Microsoft Academic Search

We report the phylogenetic utility of the nuclear gene encoding the long-wavelength opsin (LW Rh) for tribes of bees. Aligned nucleotide sequences were examined in multiple taxa from the four tribes comprising the corbiculate bees within the subfamily Apinae. Phylogenetic analyses of sequence variation in a 502-bp fragment (approx 40% of the coding region) strongly supported the monophyly of each

Patrick Mardulyn; Sydney A. Cameron

1999-01-01

121

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

Microsoft Academic Search

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

John S. Ascher; Bryan N. Danforth; Shuqing Ji

2001-01-01

122

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

123

Distinct functions for IFT140 and IFT20 in opsin transport.  

PubMed

In the vertebrate retina, light is detected by the outer segments of photoreceptor rods and cones, which are highly modified cilia. Like other cilia, outer segments have no protein synthetic capacity and depend on proteins made in the cell body for their formation and maintenance. The mechanism of transport into the outer segment is not fully understood but intraflagellar transport (IFT) is thought to be a major mechanism for moving protein from the cell body into the cilium. In the case of photoreceptor cells, the high density of receptors and the disk turnover that occurs daily necessitates much higher rates of transport than would be required in other cilia. In this work, we show that the IFT complex A protein IFT140 is required for development and maintenance of outer segments. In earlier work we found that acute deletion of Ift20 caused opsin to accumulate at the Golgi complex. In this work, we find that acute deletion of Ift140 does not cause opsin to accumulate at the Golgi complex but rather it accumulates in the plasma membrane of the inner segments. This work is a strong support of a model of opsin transport where IFT20 is involved in the movement from the Golgi complex to the base of the cilium. Then, once at the base, the opsin is carried through the connecting cilium by an IFT complex that includes IFT140. © 2014 Wiley Periodicals, Inc. PMID:24619649

Crouse, Jacquelin A; Lopes, Vanda S; Sanagustin, Jovenal T; Keady, Brian T; Williams, David S; Pazour, Gregory J

2014-05-01

124

Adaptive evolution of cone opsin genes in two colorful cyprinids, Opsariichthys pachycephalus and Candidia barbatus  

Microsoft Academic Search

Opsariichthys pachycephalus and Candidia barbatus are two phylogenetically related freshwater cyprinids that both exhibit colorful, yet quite different nuptial coloration. This study was designed to test the hypothesis that differences in nuptial coloration between two species could reflect differences in color perception ability and the opsin genes that coded for it. Genes encoding the visual pigments of these two species

Feng Yu Wang; Wen Sung Chung; Hong Young Yan; Chyng Shyan Tzeng

2008-01-01

125

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

PubMed

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

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

2011-01-01

126

Expression of UV, blue-, long-wavelength-sensitive opsins and melatonin in extraretinal photoreceptors of the optic lobes of hawkmoths  

Microsoft Academic Search

Lepidopterans display biological rhythms associated with egg laying, eclosion and flight activity but the photoreceptors that mediate these behavioural patterns are largely unknown. To further our progress in identifying candidate light-input channels for the lepidopteran circadian system, we have developed polyclonal antibodies against ultraviolet (UV)-, blue- and extraretinal long-wavelength (LW)-sensitive opsins and examined opsin immunoreactivity in the adult optic lobes

Jochen Lampel; Adriana D. Briscoe; Lutz T. Wasserthal

2005-01-01

127

The Maintenance of Reproductive Status in Pekin Drakes Requires Both Red and Blue Wavelengths of Light: Relationship to Opsin-Related Proteins in the Hypothalamus  

Microsoft Academic Search

In birds there is compelling evidence that photoresponsiveness is mediated—at least in part—by neurons that express photosensitive chemicals. These neurons have been referred to as deep encephalic photoreceptors. Photo-responsive pigments all consist of an opsin protein that is a transmembrane, G-couple receptor that transduces light energy into a neuronal signal. Two of these opsin-related proteins, opsin and melanopsin, have been

Rachel Haas

2012-01-01

128

Opsin-immunoreactive outer segments of photoreceptors in the eye and in the lumen of the optic nerve of the hagfish, Myxine glutinosa  

Microsoft Academic Search

Opsin-immunoreactive sites in the eye and optic nerve of the hagfish, Myxine glutinosa, were studied by use of light-microscopic pre- and postembedding peroxidase-antiperoxidase or avidin-biotin-peroxidase techniques, and the immuno-electron-microscopic protein A-gold method. At the light-microscopic level, a strong opsin immuno-reaction was obtained on the outer segments of the photoreceptor cells with sheep and rat antibodies against bovine (rhod)opsin. These outer

I. Vigh-Teichmann; B. Vigh; R. Olsson; Th. Veen

1984-01-01

129

Rod and Cone Opsin Families Differ in Spectral Tuning Domains but Not Signal Transducing Domains as Judged by Saturated Evolutionary Trace Analysis  

Microsoft Academic Search

The visual receptor of rods and cones is a covalent complex of the apoprotein, opsin, and the light-sensitive chromophore, 11-cis-retinal. This pigment must fulfill many functions including photoactivation, spectral tuning, signal transmission, inactivation, and chromophore regeneration. Rod and cone photoreceptors employ distinct families of opsins. Although it is well known that these opsin families provide unique ranges in spectral sensitivity,

Karen L. Carleton; Tyrone C. Spady; Rick H. Cote

2005-01-01

130

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

131

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

2013-01-01

132

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

PubMed

Genetically encoded fluorescence voltage sensors offer the possibility of directly visualizing neural spiking dynamics in cells targeted by their genetic class or connectivity. Sensors of this class have generally suffered performance-limiting tradeoffs between modest brightness, sluggish kinetics and limited signalling dynamic range in response to action potentials. Here we describe sensors that use fluorescence resonance energy transfer (FRET) to combine the rapid kinetics and substantial voltage-dependence of rhodopsin family voltage-sensing domains with the brightness of genetically engineered protein fluorophores. These FRET-opsin sensors significantly improve upon the spike detection fidelity offered by the genetically encoded voltage sensor, Arclight, while offering faster kinetics and higher brightness. Using FRET-opsin sensors we imaged neural spiking and sub-threshold membrane voltage dynamics in cultured neurons and in pyramidal cells within neocortical tissue slices. In live mice, rates and optical waveforms of cerebellar Purkinje neurons' dendritic voltage transients matched expectations for these cells' dendritic spikes. PMID:24755708

Gong, Yiyang; Wagner, Mark J; Zhong Li, Jin; Schnitzer, Mark J

2014-01-01

133

Light-controlled inhibition of malignant glioma by opsin gene transfer  

PubMed Central

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

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

2013-01-01

134

Salmonid Opsin Sequences Undergo Positive Selection and Indicate an Alternate Evolutionary Relationship in Oncorhynchus  

Microsoft Academic Search

Positive selection can be demonstrated by statistical analysis when non-synonymous nucleotide substitutions occur more frequently than synonymous substitutions (dN>dS). This pattern of sequence evolution has been observed in the rhodopsin gene of cichlids. Mutations in opsin genes resulting in amino acid (AA) replacement appear to be associated with the evolution of specific color patterns and the evolution of courtship behaviors.

Stephen G. Dann; W. Ted Allison; David B. Levin; John S. Taylor; Craig W. Hawryshyn

2004-01-01

135

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

Microsoft Academic Search

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

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

1998-01-01

136

Differentially-expressed opsin genes identified in Sinocyclocheilus cavefish endemic to China  

PubMed Central

Eye degeneration is a common troglomorphic character of cave-dwelling organisms. Comparing the morphology and molecular biology of cave species and their close surface relatives is a powerful tool for studying regressive eye evolution and other adaptive phenotypes. We compared two co-occurring and closely-related species of the fish genus Sinocyclocheilus, which is endemic to China and includes both surface- and cave-dwelling species. Sinocyclocheilus tileihornes, a cave species, had smaller eyes than Sinocyclocheilus angustiporus, a surface species. Histological and immunohistochemical analyses revealed that the cavefish had shorter cones and more disorderly rods than did the surface-dwelling species. Using quantitative PCR and in situ hybridization, we found that rhodopsin and a long-wavelength sensitive opsin had significantly lower expression levels in the cavefish. Furthermore, one of two short-wavelength-sensitive opsins was expressed at significantly higher levels in the cavefish. Changes in the expression of opsin genes may have played a role in the degeneration of cavefish eyes

Meng, Fanwei; Zhao, Yahui; Postlethwait, John H.; Zhang, Chunguang

2013-01-01

137

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

PubMed

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

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

2014-04-01

138

Opsins in onychophora (velvet worms) suggest a single origin and subsequent diversification of visual pigments in arthropods.  

PubMed

Multiple visual pigments, prerequisites for color vision, are found in arthropods, but the evolutionary origin of their diversity remains obscure. In this study, we explore the opsin genes in five distantly related species of Onychophora, using deep transcriptome sequencing and screening approaches. Surprisingly, our data reveal the presence of only one opsin gene (onychopsin) in each onychophoran species, and our behavioral experiments indicate a maximum sensitivity of onychopsin to blue-green light. In our phylogenetic analyses, the onychopsins represent the sister group to the monophyletic clade of visual r-opsins of arthropods. These results concur with phylogenomic support for the sister-group status of the Onychophora and Arthropoda and provide evidence for monochromatic vision in velvet worms and in the last common ancestor of Onychophora and Arthropoda. We conclude that the diversification of visual pigments and color vision evolved in arthropods, along with the evolution of compound eyes-one of the most sophisticated visual systems known. PMID:22683812

Hering, Lars; Henze, Miriam J; Kohler, Martin; Kelber, Almut; Bleidorn, Christoph; Leschke, Maren; Nickel, Birgit; Meyer, Matthias; Kircher, Martin; Sunnucks, Paul; Mayer, Georg

2012-11-01

139

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

2013-01-01

140

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

PubMed Central

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

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

2013-01-01

141

Substitution of isoleucine for threonine at position 190 of S-opsin causes S-cone-function abnormalities.  

PubMed

Five mutations in the S-cone-opsin gene (OPN1SW) that give rise to different single amino-acid substitutions (L56P, G79R, S214P, P264S, R283Q) are known to be associated with tritan color-vision deficiency. Here we report a sixth OPN1SW mutation (T190I) and the associated color vision phenotype. S-opsin genotyping and clinical evaluation of color vision were performed on affected and unaffected family members and normal controls. Chromatic contrast was tested at different levels of retinal illuminance. Affected family members were heterozygous for a nucleotide change that substituted the amino acid isoleucine (I) in place of threonine (T) that is normally present at position 190 of the S-opsin. The mutation is in extracellular loop II (EII). The association between making tritan errors and having the T190I mutant S opsin was strong (p>0.0001: Fisher's exact test). The performance of subjects with the T190I mutation was significantly different from that of normal trichromats along the tritan vector under all conditions tested (Mann-Whitney U: p<0.05), but not along the protan or deutan vectors. Individuals with the T190I S-opsin mutation behaved as mild tritans at 12.3-92.3Td, but as tritanopes at 1.2-9.2Td, for both light-adapted and dark-adapted conditions. The results are consistent with the mutant opsin causing abnormal S-cone function. PMID:23022137

Baraas, Rigmor C; Hagen, Lene A; Dees, Elise W; Neitz, Maureen

2012-11-15

142

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

PubMed

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

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

2013-05-22

143

Cnidocyte discharge is regulated by light and opsin-mediated phototransduction  

PubMed Central

Background Cnidocytes, the eponymous cell type of the Cnidaria, facilitate both sensory and secretory functions and are among the most complex animal cell types known. In addition to their structural complexity, cnidocytes display complex sensory attributes, integrating both chemical and mechanical cues from the environment into their discharge behavior. Despite more than a century of work aimed at understanding the sensory biology of cnidocytes, the specific sensory receptor genes that regulate their function remain unknown. Results Here we report that light also regulates cnidocyte function. We show that non-cnidocyte neurons located in battery complexes of the freshwater polyp Hydra magnipapillata specifically express opsin, cyclic nucleotide gated (CNG) ion channel and arrestin, which are all known components of bilaterian phototransduction cascades. We infer from behavioral trials that different light intensities elicit significant effects on cnidocyte discharge propensity. Harpoon-like stenotele cnidocytes show a pronounced diminution of discharge behavior under bright light conditions as compared to dim light. Further, we show that suppression of firing by bright light is ablated by cis-diltiazem, a specific inhibitor of CNG ion channels. Conclusions Our results implicate an ancient opsin-mediated phototransduction pathway and a previously unknown layer of sensory complexity in the control of cnidocyte discharge. These findings also suggest a molecular mechanism for the regulation of other cnidarian behaviors that involve both photosensitivity and cnidocyte function, including diurnal feeding repertoires and/or substrate-based locomotion. More broadly, our findings highlight one novel, non-visual function for opsin-mediated phototransduction in a cnidarian, the origins of which might have preceded the evolution of cnidarian eyes.

2012-01-01

144

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

145

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

PubMed Central

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

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

2012-01-01

146

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

PubMed Central

Circadian rhythms are endogenous 24 h cycles that persist in the absence of external time cues. These rhythms provide an internal representation of day length and optimize physiology and behaviour to the varying demands of the solar cycle. These clocks require daily adjustment to local time and the primary time cue (zeitgeber) used by most vertebrates is the daily change in the amount of environmental light (irradiance) at dawn and dusk, a process termed photoentrainment. Attempts to understand the photoreceptor mechanisms mediating non-image-forming responses to light, such as photoentrainment, have resulted in the discovery of a remarkable array of different photoreceptors and photopigment families, all of which appear to use a basic opsin/vitamin A-based photopigment biochemistry. In non-mammalian vertebrates, specialized photoreceptors are located within the pineal complex, deep brain and dermal melanophores. There is also strong evidence in fish and amphibians for the direct photic regulation of circadian clocks in multiple tissues. By contrast, mammals possess only ocular photoreceptors. However, in addition to the image-forming rods and cones of the retina, there exists a third photoreceptor system based on a subset of melanopsin-expressing photosensitive retinal ganglion cells (pRGCs). In this review, we discuss the range of vertebrate photoreceptors and their opsin photopigments, describe the melanopsin/pRGC system in some detail and then finally consider the molecular evolution and sensory ecology of these non-image-forming photoreceptor systems.

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

2009-01-01

147

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

PubMed

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

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

2012-04-15

148

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

PubMed

Circadian rhythms are endogenous 24 h cycles that persist in the absence of external time cues. These rhythms provide an internal representation of day length and optimize physiology and behaviour to the varying demands of the solar cycle. These clocks require daily adjustment to local time and the primary time cue (zeitgeber) used by most vertebrates is the daily change in the amount of environmental light (irradiance) at dawn and dusk, a process termed photoentrainment. Attempts to understand the photoreceptor mechanisms mediating non-image-forming responses to light, such as photoentrainment, have resulted in the discovery of a remarkable array of different photoreceptors and photopigment families, all of which appear to use a basic opsin/vitamin A-based photopigment biochemistry. In non-mammalian vertebrates, specialized photoreceptors are located within the pineal complex, deep brain and dermal melanophores. There is also strong evidence in fish and amphibians for the direct photic regulation of circadian clocks in multiple tissues. By contrast, mammals possess only ocular photoreceptors. However, in addition to the image-forming rods and cones of the retina, there exists a third photoreceptor system based on a subset of melanopsin-expressing photosensitive retinal ganglion cells (pRGCs). In this review, we discuss the range of vertebrate photoreceptors and their opsin photopigments, describe the melanopsin/pRGC system in some detail and then finally consider the molecular evolution and sensory ecology of these non-image-forming photoreceptor systems. PMID:19720649

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

2009-10-12

149

Immune responsiveness to retinal S-antigen and opsin in serpiginous choroiditis and other retinal diseases.  

PubMed

The immune responsiveness to bovine retinal S-antigen and opsin has been investigated in some retinal disorders by means of in vitro lymphocyte proliferation, leukocyte migration inhibition and enzyme linked immune sorbent assays (ELISA). Sensitisation to S-antigen was observed in serpiginous choroiditis, but not in acute posterior multifocal placoid pigment epitheliopathy (APMPPE) or retinitis pigmentosa. No significant immune responsiveness was detected to opsin in any of the three diseases. Elevated antibody titers to S-antigen were observed in some individual patients and healthy subjects. However, none of the patient groups exhibited an elevated antibody titer as compared to the control group. Although serpiginous choroiditis and APMPPE share some prominent clinical characteristics, the sensitisation in the former disease may perhaps be attributed to more severe and prolonged damage of the photoreceptor cells and blood-retina barrier. A combination of previous and present results suggests that in immunological investigations of retinitis pigmentosa patients it is more effective to use human than bovine S-antigen as test antigen because a species specific epitope seems to be involved. PMID:2971518

Broekhuyse, R M; van Herck, M; Pinckers, A J; Winkens, H J; van Vugt, A H; Ryckaert, S; Deutman, A F

1988-05-01

150

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

151

Signatures of Functional Constraint at Aye-aye Opsin Genes: The Potential of Adaptive Color Vision in a Nocturnal Primate  

Microsoft Academic Search

While color vision perception is thought to be adaptively correlated with foraging efficiency for diurnal mammals, those that forage exclusively at night may not need color vision nor have the capacity for it. Indeed, although the basic condition for mammals is dichromacy, diverse nocturnal mammals have only monochromatic vision, resulting from functional loss of the short-wavelength sensitive opsin gene. However,

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

2007-01-01

152

Population variation in opsin expression in the bluefin killifish, Lucania goodei : a real-time PCR study  

Microsoft Academic Search

Quantitative genetics have not been used in vision studies because of the difficulty of objectively measuring large numbers of individuals. Here, we examine the effectiveness of a molecular technique, real-time PCR, as an inference of visual components in the bluefin killifish, Lucania goodei, to determine whether there is population variation in opsin expression. Previous work has shown that spring animals

R. C. Fuller; K. L. Carleton; J. M. Fadool; T. C. Spady; J. Travis

2004-01-01

153

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

NASA Technical Reports Server (NTRS)

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

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

2001-01-01

154

Opsin activation of transduction in the rods of dark-reared Rpe65 knockout mice  

PubMed Central

Rpe65 knockout mice (Rpe65?/?) are unable to synthesize the visual pigment chromophore 11-cis retinal; however, if these animals are reared in complete darkness, the rod photoreceptors accumulate a small amount of 9-cis retinal and its corresponding visual pigment isorhodopsin. Suction-electrode recording of single rods from dark-reared Rpe65?/? mice showed that the rods were about 400 times less sensitive than wild-type control rods and that the maximum responses were much smaller in amplitude. Spectral sensitivity measurements indicated that Rpe65?/? rod responses were generated by isorhodopsin rather than rhodopsin. Sensitivity and pigment concentration were compared in the same mice by measuring light responses from rods of one eye and pigment concentration from the retina of the other eye. Retinas had 11–35% of the normal pigment level, but the rods were of the order of 20–30 times less sensitive than could be accounted for by the loss in quantum catch. This extra desensitization must be caused by opsin-dependent activation of the visual cascade, which leads to a state equivalent to light adaptation in the dark-adapted rod. By comparing the sensitivity of dark-reared Rpe65?/? rods to that produced in normal rods by background light, we estimate that Rpe65?/? opsin is of the order of 2.5 × 10?5 as efficient in activating transduction as photoactivated rhodopsin (Rh*) in WT mice. Dark-reared Rpe65?/? rods are less desensitized than rods from cyclic light-reared Rpe65?/? mice, have about 50% more photocurrent and degenerate at a slower rate. Retinas sectioned after 9 months in darkness show a larger number of photoreceptor nuclei in dark-reared animals than in cyclic light-reared animals, though both have fewer nuclei than in cyclic light-reared wild-type retinas. Both also have shorter outer segments and a lower free-Ca2+ concentration. These experiments provide the first quantitative measurement of opsin activation in physiologically responding mammalian rods.

Fan, Jie; Woodruff, Michael L; Cilluffo, Marianne C; Crouch, Rosalie K; Fain, Gordon L

2005-01-01

155

Extraordinarily low evolutionary rates of short wavelength-sensitive opsin pseudogenes.  

PubMed

Aquatic organisms such as cichlids, coelacanths, seals, and cetaceans are active in UV-blue color environments, but many of them mysteriously lost their abilities to detect these colors. The loss of these functions is a consequence of the pseudogenization of their short wavelength-sensitive (SWS1) opsin genes without gene duplication. We show that the SWS1 gene (BdenS1?) of the deep-sea fish, pearleye (Benthalbella dentata), became a pseudogene in a similar fashion about 130 million years ago (Mya) yet it is still transcribed. The rates of nucleotide substitution (~1.4 × 10(-9)/site/year) of the pseudogenes of these aquatic species as well as some prosimian and bat species are much smaller than the previous estimates for the globin and immunoglobulin pseudogenes. PMID:24125953

Yokoyama, Shozo; Starmer, William T; Liu, Yang; Tada, Takashi; Britt, Lyle

2014-01-15

156

A Blind Circadian Clock in Cavefish Reveals that Opsins Mediate Peripheral Clock Photoreception  

PubMed Central

The circadian clock is synchronized with the day-night cycle primarily by light. Fish represent fascinating models for deciphering the light input pathway to the vertebrate clock since fish cell clocks are regulated by direct light exposure. Here we have performed a comparative, functional analysis of the circadian clock involving the zebrafish that is normally exposed to the day-night cycle and a cavefish species that has evolved in perpetual darkness. Our results reveal that the cavefish retains a food-entrainable clock that oscillates with an infradian period. Importantly, however, this clock is not regulated by light. This comparative study pinpoints the two extra-retinal photoreceptors Melanopsin (Opn4m2) and TMT-opsin as essential upstream elements of the peripheral clock light input pathway.

Cavallari, Nicola; Frigato, Elena; Vallone, Daniela; Frohlich, Nadine; Lopez-Olmeda, Jose Fernando; Foa, Augusto; Berti, Roberto; Sanchez-Vazquez, Francisco Javier; Bertolucci, Cristiano; Foulkes, Nicholas S.

2011-01-01

157

Chromatin immunoprecipitation assay on the rainbow trout opsin proximal promoters illustrates binding of NF-?B and c-jun to the SWS1 promoter in the retina  

Microsoft Academic Search

Misexpression of opsins has been linked to apoptosis of photoreceptor cells in the vertebrate retina. Salmonid fish lose their ultraviolet-sensitive (UVS) cones through post-natal developmental apoptosis mediated by thyroid hormone (TH). In order to identify genetic mechanisms that may play a role in the loss of UVS cones, the transcriptional regulation of the SWS1 opsin in the rainbow trout (Oncorhynchus

Stephen G. Dann; W. Ted Allison; Kathy Veldhoen; Trudi Johnson; Craig W. Hawryshyn

2004-01-01

158

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

Microsoft Academic Search

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

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

1988-01-01

159

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

Microsoft Academic Search

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\\u000a wavelength-absorbing visual pigments. Duplication of the blue visual pigment class occurs also in another pierid species,\\u000a Pieris rapae, suggesting that blue duplication is a

Hiroko Awata; Motohiro Wakakuwa; Kentaro Arikawa

2009-01-01

160

Photoreceptors of Nrl ?/? Mice Coexpress Functional S- and M-cone Opsins Having Distinct Inactivation Mechanisms  

PubMed Central

The retinas of mice null for the neural retina leucine zipper transcription factor (Nrl ?/?) contain no rods but are populated instead with photoreceptors that on ultrastructural, histochemical, and molecular criteria appear cone like. To characterize these photoreceptors functionally, responses of single photoreceptors of Nrl ?/? mice were recorded with suction pipettes at 35–37°C and compared with the responses of rods of WT mice. Recordings were made either in the conventional manner, with the outer segment (OS) drawn into the pipette (“OS in”), or in a novel configuration with a portion of the inner segment drawn in (“OS out”). Nrl ?/? photoreceptor responses recorded in the OS-out configuration were much faster than those of WT rods: for dim-flash responses tpeak = 91 ms vs. 215 ms; for saturating flashes, dominant recovery time constants, ?D = 110 ms vs. 240 ms, respectively. Nrl ?/? photoreceptors in the OS-in configuration had reduced amplification, sensitivity, and slowed recovery kinetics, but the recording configuration had no effect on rod response properties, suggesting Nrl ?/? outer segments to be more susceptible to damage. Functional coexpression of two cone pigments in a single mammalian photoreceptor was established for the first time; the responses of every Nrl ?/? cell were driven by both the short-wave (S, ?max ? 360 nm) and the mid-wave (M, ?max ? 510 nm) mouse cone pigment; the apparent ratio of coexpressed M-pigment varied from 1:1 to 1:3,000 in a manner reflecting a dorso-ventral retinal position gradient. The role of the G-protein receptor kinase Grk1 in cone pigment inactivation was investigated in recordings from Nrl ?/?/Grk1?/? photoreceptors. Dim-flash responses of cells driven by either the S- or the M-cone pigment were slowed 2.8-fold and 7.5-fold, respectively, in the absence of Grk1; the inactivation of the M-pigment response was much more seriously retarded. Thus, Grk1 is essential to normal inactivation of both S- and M-mouse cone opsins, but S-opsin has access to a relatively effective, Grk1-independent inactivation pathway.

Nikonov, Sergei S.; Daniele, Lauren L.; Zhu, Xuemei; Craft, Cheryl M.; Swaroop, Anand; Pugh, Edward N.

2005-01-01

161

Time-resolved fluorescence spectroscopy measures clustering and mobility of a g protein-coupled receptor opsin in live cell membranes.  

PubMed

Determining membrane protein quaternary structure is extremely challenging, especially in live cell membranes. We measured the oligomerization of opsin, a prototypical G protein-coupled receptor with pulsed-interleaved excitation fluorescence cross-correlation spectroscopy (PIE-FCCS). Individual cell measurements revealed that opsin is predominantly organized into dimeric clusters. At low concentrations, we observed that the population of oligomers increased linearly with the square of the individual monomer populations. This finding supports a monomer-dimer equilibrium and provides an experimental measurement of the equilibrium constant. PMID:24831851

Comar, William D; Schubert, Sarah M; Jastrzebska, Beata; Palczewski, Krzysztof; Smith, Adam W

2014-06-11

162

The transporter-opsin-G protein-coupled receptor (TOG) superfamily.  

PubMed

Visual rhodopsins are recognized members of the large and diverse family of G protein-coupled receptors (GPCRs), but their evolutionary origin and relationships to other proteins are not known. In a previous paper [Shlykov MA, Zheng WH, Chen JS & Saier MH Jr (2012) Biochim Biophys Acta 1818, 703-717], we characterized the 4-toluene sulfonate uptake permease (TSUP) family of transmembrane proteins, and showed that these 7-transmembrane segment (TMS) or 8-TMS proteins arose by intragenic duplication of a gene encoding a 4-TMS protein, sometimes followed by loss of a terminal TMS. In this study, we show that the TSUP, GPCR and microbial rhodopsin families are related to each other and to six other currently recognized transport protein families. We designate this superfamily the transporter/opsin/G protein-coupled receptor (TOG) superfamily. Despite their 8-TMS origins, the members of most constituent families exhibit 7-TMS topologies that are well conserved, and these arose by loss of either the N-terminal TMS (more frequent) or the C-terminal TMS (less frequent), depending on the family. Phylogenetic analyses revealed familial relationships within the superfamily and protein relationships within each of the nine families. The results of the statistical analyses leading to the conclusion of homology were confirmed using hidden Markov models, Pfam and 3D superimpositions. Proteins functioning by dissimilar mechanisms (channels, primary active transporters, secondary active transporters, group translocators and receptors) are interspersed on a phylogenetic tree of the TOG superfamily, suggesting that changes in the transport and energy-coupling mechanisms occurred multiple times during evolution of this superfamily. PMID:23981446

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

2013-11-01

163

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

2013-09-01

164

Probing Mechanisms of Photoreceptor Degeneration in a New Mouse Model of the Common Form of Autosomal Dominant Retinitis Pigmentosa due to P23H Opsin Mutations*?  

PubMed Central

Rhodopsin, the visual pigment mediating vision under dim light, is composed of the apoprotein opsin and the chromophore ligand 11-cis-retinal. A P23H mutation in the opsin gene is one of the most prevalent causes of the human blinding disease, autosomal dominant retinitis pigmentosa. Although P23H cultured cell and transgenic animal models have been developed, there remains controversy over whether they fully mimic the human phenotype; and the exact mechanism by which this mutation leads to photoreceptor cell degeneration remains unknown. By generating P23H opsin knock-in mice, we found that the P23H protein was inadequately glycosylated with levels 1–10% that of wild type opsin. Moreover, the P23H protein failed to accumulate in rod photoreceptor cell endoplasmic reticulum but instead disrupted rod photoreceptor disks. Genetically engineered P23H mice lacking the chromophore showed accelerated photoreceptor cell degeneration. These results indicate that most synthesized P23H protein is degraded, and its retinal cytotoxicity is enhanced by lack of the 11-cis-retinal chromophore during rod outer segment development.

Sakami, Sanae; Maeda, Tadao; Bereta, Grzegorz; Okano, Kiichiro; Golczak, Marcin; Sumaroka, Alexander; Roman, Alejandro J.; Cideciyan, Artur V.; Jacobson, Samuel G.; Palczewski, Krzysztof

2011-01-01

165

Proteomic analysis of opsins and thyroid hormone-induced retinal development using isotope-coded affinity tags (ICAT) and mass spectrometry  

Microsoft Academic Search

Purpose: Analyses that reveal the relative abundance of proteins are informative in elucidating mechanisms of retinal development and disease progression. However, popular high-throughput proteomic methods do not reliably detect opsin protein abundance, which serve as markers of photoreceptor differentiation. We utilized thyroid-hormone (TH) treatment of rainbow trout (Oncorhynchus mykiss) as a model of cone apoptosis and cone regeneration. We used

W. Ted Allison; Kathy M. Veldhoen; Craig W. Hawryshyn

2006-01-01

166

X-linked cone dystrophy and colour vision deficiency arising from a missense mutation in a hybrid L/M cone opsin gene.  

PubMed

In this report, we describe a male subject who presents with a complex phenotype of myopia associated with cone dysfunction and a protan vision deficiency. Retinal imaging demonstrates extensive cone disruption, including the presence of non-waveguiding cones, an overall thinning of the retina, and an irregular mottled appearance of the hyper-reflective band associated with the inner segment ellipsoid portion of the photoreceptor. Mutation screening revealed a novel p.Glu41Lys missense mutation in a hybrid L/M opsin gene. Spectral analysis shows that the mutant opsin fails to form a pigment in vitro and fails to be trafficked to the cell membrane in transfected Neuro2a cells. Extensive sequence and quantitative PCR analysis identifies this mutant gene as the only gene present in the affected subject's L/M opsin gene array, yet the presence of protanopia indicates that the mutant opsin must retain some activity in vivo. To account for this apparent contradiction, we propose that a limited amount of functional pigment is formed within the normal cellular environment of the intact photoreceptor, and that this requires the presence of chaperone proteins that promote stability and normal folding of the mutant protein. PMID:23337435

McClements, Michelle; Davies, Wayne I L; Michaelides, Michel; Carroll, Joseph; Rha, Jungtae; Mollon, John D; Neitz, Maureen; MacLaren, Robert E; Moore, Anthony T; Hunt, David M

2013-03-22

167

X-linked cone dystrophy and colour vision deficiency arising from a missense mutation in a hybrid L/M cone opsin gene  

PubMed Central

In this report, we describe a male subject who presents with a complex phenotype of myopia associated with cone dysfunction and a protan vision deficiency. Retinal imaging demonstrates extensive cone disruption, including the presence of non-waveguiding cones, an overall thinning of the retina, and an irregular mottled appearance of the hyper reflective band associated with the inner segment ellipsoid portion of the photoreceptor. Mutation screening revealed a novel p.Glu41Lys missense mutation in a hybrid L/M opsin gene. Spectral analysis shows that the mutant opsin fails to form a pigment in vitro and fails to be trafficked to the cell membrane in transfected Neuro2a cells. Extensive sequence and quantitative PCR analysis identifies this mutant gene as the only gene present in the affected subject’s L/M opsin gene array, yet the presence of protanopia indicates that the mutant opsin must retain some activity in vivo. To account for this apparent contradiction, we propose that a limited amount of functional pigment is formed within the normal cellular environment of the intact photoreceptor, and that this requires the presence of chaperone proteins that promote stability and normal folding of the mutant protein.

McClements, Michelle; Davies, Wayne I L; Michaelides, Michel; Carroll, Joseph; Rha, Jungate; Mollon, John D; Neitz, Maureen; MacLaren, Robert E; Moore, Anthony T; Hunt, David M

2013-01-01

168

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

169

Mutations of the Opsin Gene (Y102H and I307N) Lead to Light-induced Degeneration of Photoreceptors and Constitutive Activation of Phototransduction in Mice*  

PubMed Central

Mutations in the Rhodopsin (Rho) gene can lead to autosomal dominant retinitis pigmentosa (RP) in humans. Transgenic mouse models with mutations in Rho have been developed to study the disease. However, it is difficult to know the source of the photoreceptor (PR) degeneration in these transgenic models because overexpression of wild type (WT) Rho alone can lead to PR degeneration. Here, we report two chemically mutagenized mouse models carrying point mutations in Rho (Tvrm1 with an Y102H mutation and Tvrm4 with an I307N mutation). Both mutants express normal levels of rhodopsin that localize to the PR outer segments and do not exhibit PR degeneration when raised in ambient mouse room lighting; however, severe PR degeneration is observed after short exposures to bright light. Both mutations also cause a delay in recovery following bleaching. This defect might be due to a slower rate of chromophore binding by the mutant opsins compared with the WT form, and an increased rate of transducin activation by the unbound mutant opsins, which leads to a constitutive activation of the phototransduction cascade as revealed by in vitro biochemical assays. The mutant-free opsins produced by the respective mutant Rho genes appear to be more toxic to PRs, as Tvrm1 and Tvrm4 mutants lacking the 11-cis chromophore degenerate faster than mice expressing WT opsin that also lack the chromophore. Because of their phenotypic similarity to humans with B1 Rho mutations, these mutants will be important tools in examining mechanisms underlying Rho-induced RP and for testing therapeutic strategies.

Budzynski, Ewa; Gross, Alecia K.; McAlear, Suzanne D.; Peachey, Neal S.; Shukla, Meera; He, Feng; Edwards, Malia; Won, Jungyeon; Hicks, Wanda L.; Wensel, Theodore G.; Naggert, Jurgen K.; Nishina, Patsy M.

2010-01-01

170

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

PubMed

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

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

2012-05-01

171

Six Opsins from the Butterfly Papilio glaucus: Molecular Phylogenetic Evidence for Paralogous Origins of Red-Sensitive Visual Pigments in Insects  

Microsoft Academic Search

.   It has been hypothesized that the UV-, blue-, and green-sensitive visual pigments of insects were present in the common ancestor\\u000a of crustaceans and insects, whereas red-sensitive visual pigments evolved later as a result of convergent evolution. This\\u000a hypothesis is examined with respect to the placement of six opsins from the swallowtail butterfly Papilio glaucus (PglRh1–6) in relationship to 46

Adriana D. Briscoe

2000-01-01

172

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

PubMed Central

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

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

2011-01-01

173

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

PubMed Central

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

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

2013-01-01

174

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

PubMed Central

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

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

2003-01-01

175

Evolution of vertebrate visual pigments  

Microsoft Academic Search

The visual pigments of vertebrates evolved about 500 million years ago, before the major evolutionary step of the development of jaws. Four spectrally distinct classes of cone opsin evolved through gene duplication, followed by the rod opsin class that arose from the duplication of the middle-wave-sensitive cone opsin. All four cone classes are present in many extant teleost fish, reptiles

James K. Bowmaker

2008-01-01

176

Opsins and mammalian photoentrainment  

Microsoft Academic Search

Research over the past decade has provided overwhelming evidence that photoreception in the vertebrate eye is not confined to the rod and cone photoreceptors. It appears that photoreceptor cells within the inner retina provide irradiance information to a wide variety of different photosensory tasks including photoentrainment, pupillary constriction and masking behaviour. Action spectra in mice lacking all rod and cone

James Bellingham; Russell G. Foster

2002-01-01

177

The fungal opsin gene nop-1 is negatively-regulated by a component of the blue light sensing pathway and influences conidiation-specific gene expression in Neurospora crassa  

Microsoft Academic Search

We previously demonstrated that the nop-1 gene encodes a putative green-light opsin photoreceptor that is highly expressed in cultures that support asexual sporulation\\u000a (conidiation) in Neurospora crassa. In this study, we demonstrate that nop-1 is a late-stage conidiation gene, through analysis of nop-1 transcript levels in wild-type strains and mutants blocked at various stages of conidiation. nop-1 message amounts are

Jennifer A. Bieszke; Liande Li; Katherine A. Borkovich

2007-01-01

178

Studies for Improved Gravitational Wave Sensitivity  

NASA Technical Reports Server (NTRS)

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

Bender, Peter L.

2003-01-01

179

Prospects of Russian participation in the international LWS program  

NASA Astrophysics Data System (ADS)

This report describes current and future solar-terrestrial space missions of the Russian Federal Space Agency. They are discussed in the context of the International Living With a Star activity aimed at consolidation of efforts in developing a balanced cooperative program of solar-terrestrial and space weather oriented research. We provide information on several missions that are at different stages of realization: solar observing - CORONAS-F, CORONAS-PHOTON, and INTERHELIOPROBE; and magnetospheric - RESONANCE, ROY, and INTERBALL-PROGNOZ.

Zelenyi, L. M.; Petrukovich, A. A.

180

LWS design replacement study: Optimum design and tradeoff analysis  

NASA Technical Reports Server (NTRS)

A design for two long-wavelength (LW) focal-plane and cooler assemblies, including associated preamplifiers and post-amplifiers is presented. The focal-planes and associated electronic assemblies are intended as direct replacement hardware to be installed into the existing 24-channel multispectral scanner used with the NASA Earth Observations Aircraft Program. An organization skilled in the art of LWIR systems can fabricate and deliver the two long-wavelength focal-plane assemblies described in this report when provided with the data and drawings developed during the performance of this contract. The concepts developed during the study including the alternative approaches and selection of components are discussed. Modifications to the preliminary design as reported in a preliminary design review meeting have also been included.

1973-01-01

181

ISO Guest Observer Data Analysis and LWS Instrument Team Activities  

NASA Technical Reports Server (NTRS)

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

Smith, Howard

2001-01-01

182

ISO Guest Observer Data Analysis and LWS Instrument Team Activities  

NASA Technical Reports Server (NTRS)

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

2002-01-01

183

Surface-wave sensitivity to 3-D anelasticity  

NASA Astrophysics Data System (ADS)

Lateral variations in mantle anelasticity (Q) are important for understanding the Earth's thermal and chemical structure in the mantle. In the past decades, preliminary global 3-D tomographic Q models have been developed based upon the assumption that traveltime (phase delay) anomalies are due to the Earth's elastic (velocity) structure whereas amplitude anomalies are dominated by 3-D anelastic (Q) structure. In this paper, we calculate the 3-D finite-frequency sensitivity of fundamental-mode surface-wave phase delays and amplitudes to perturbations in anelasticity (Q). Calculations of Q and velocity sensitivity kernels show that (1) roughly 15-20 per cent of observed phase delays in long-period surface waves can be explained by lateral variations in Q in the upper mantle; and (2) focusing and defocusing effects due to 3-D velocity structure account for a major portion of observed amplitude perturbations in long-period surface waves. The coupling between elastic and anelastic effects in both seismic traveltimes and amplitudes indicates that a joint inversion of 3-D velocity and 3-D Q structure accounting for both anelastic dispersion and associated focusing and defocusing effects is necessary in mapping lateral heterogeneities in the upper mantle.

Zhou, Ying

2009-09-01

184

Cone visual pigments in two species of South American marsupials.  

PubMed

Marsupials are largely confined to Australasia and to Central and South America. The visual pigments that underlie the photosensitivity of the retina have been examined in a number of species from the former group where evidence for trichromatic colour vision has been found, but none from the latter. In this paper, we report the cone opsin sequences from two nocturnal South American marsupial species, the gray short-tailed opossum, Monodelphis domestica, and the big-eared opossum, Didelphis aurita. Both are members of the Order Didelphimorphia (American opossums). For both species, only two classes of cone opsin were found, an SWS1 and an LWS sequence, and in vitro expression showed that the peak sensitivity of the SWS1 pigment is in the UV. Analysis of the Monodelphis genome confirms the absence of other classes of cone visual pigment genes. The SWS1 and LWS genes with 4 and 5 introns respectively, show the same exon-intron structure as found for these genes in all other vertebrates. The SWS1 gene shows a conserved synteny with flanking genes. The LWS gene is X-linked, as in all therian mammals so far examined, with a locus control region 1.54 kb upstream. PMID:19133321

Hunt, David M; Chan, Jaclyn; Carvalho, Livia S; Hokoc, Jan N; Ferguson, Margo C; Arrese, Catherine A; Beazley, Lyn D

2009-03-15

185

Cone monochromacy and visual pigment spectral tuning in wobbegong sharks.  

PubMed

Much is known regarding the evolution of colour vision in nearly every vertebrate class, with the notable exception of the elasmobranchs. While multiple spectrally distinct cone types are found in some rays, sharks appear to possess only a single class of cone and, therefore, may be colour blind. In this study, the visual opsin genes of two wobbegong species, Orectolobus maculatus and Orectolobus ornatus, were isolated to verify the molecular basis of their monochromacy. In both species, only two opsin genes are present, RH1 (rod) and LWS (cone), which provide further evidence to support the concept that sharks possess only a single cone type. Examination of the coding sequences revealed substitutions that account for interspecific variation in the photopigment absorbance spectra, which may reflect the difference in visual ecology between these species. PMID:22993239

Theiss, Susan M; Davies, Wayne I L; Collin, Shaun P; Hunt, David M; Hart, Nathan S

2012-12-23

186

Far Infrared spectroscopy of normal galaxies with ISO-LWS: Physical conditions in the Interstellar Medium  

NASA Astrophysics Data System (ADS)

We present measurements of FIR cooling lines from neutral and ionized ISM of 60 normal, star-forming galaxies, selected to span a range in morphology, FIR colors indicating dust temperatures, and FIR/Blue ratios (indicating star-formation activity, optical depth). From the trends seen in the data and comparison with theoretical models we draw the following main conclusions: (1) The ratio of [CII](158 ? m)/FIR declines with increasing dust temperature and star-forming activity in galaxies; spannning a factor of more than 50 in [CII]/FIR with [CII] deficient galaxies at its extreme end. (2) The ratio of [OI]/[CII] lines increases for galaxies with higher F60/F100. In galaxies with warmer dust, there is less cooling via the [CII] line, while [OI] at 63 ? m remains a major coolant. This trend is explained in PDR models by an increase in UV radiation field G0, which raises both the gas and dust temperature. (3) [NII] (122 ? m) from ionized regions, shows behavior similar to [CII], i.e. the ratio [NII]/FIR declines with F60/F100 and L(FIR)/L(B). This suggests that a fair fraction of [CII] comes from ionized gas. We derive theoretical scaling between [NII](122 ? m) and [CII] from ionized gas and use that scaling to estimate the [CII] flux from neutral regions [CII]c. (4) By comparing the observed ratios of [OI](63? m) and [CII]c lines and the ratio of line to the total FIR continuum from dust with a grid of PDR models, we derive the UV radiation density G0 and gas densities n in the sample galaxies. G0 and n correlate with each other and G0 increases as n1.4. Since G0 can be used as a measure of current star-formation, this directly confirms Schmidt law of star-formation where the star-formation increases with gas density to some power.

Malhotra, S.; Kaufman, M.; Hollenbach, D.; Helou, G.; Rubin, R.; Brauher, J.; Dale, D.; Lu, N. Y.; Lord, S. D.; Contursi, A.; Jarrett, T.; Hunter, D.

1999-12-01

187

The LWS Geospace Storm Investigations Exploring the Extremes of Space Weather  

NASA Technical Reports Server (NTRS)

The Geospace mission of the Living With a Star program is a family of investigations focusing on the compelling science questions that advance our ability to specify, understand, and predict the societal impact of solar variance. Two key areas have been identified as combining both importance to society and potential for scientific progress: 1) characterization and understanding of the acceleration, global distribution, and variability of energetic electrons and ions in the inner magnetosphere, and 2) characterization and understanding of the ionosphere and irregularities that affect communications, navigation and radar systems. Under these broad categories specific science questions have emerged as the priority science objectives for the first Geospace Investigations: How and why do relativistic electrons in the outer zone and slot region vary during geomagnetic storms? How does the long- and short-term variability of the Sun affect the global-scale behavior of the ionospheric electron density and irregularities, especially during magnetic storms and at mid-latitudes? The first Geospace mission will attempt to answer these questions.

2002-01-01

188

Isolation and characterization of the opsin gene from Halobacterium halobium  

SciTech Connect

The purpose of this project was to clone and characterize the gene which codes for bacteriorhodopsin in halobacteria. Three approaches were used in the attempt: Plus-minus hybridization using labelled RNAs from an overproducer and a nonproducer mutant, screening genomic libraries using synthetic oligomeric probes, and screening of plasmids from producer and nonproducer cells.

Not Available

1984-01-01

189

Visual sensitivities tuned by heterochronic shifts in opsin gene expression  

Microsoft Academic Search

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

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

2008-01-01

190

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

PubMed

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

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

2009-06-10

191

Parallel and convergent evolution of the dim-light vision gene RH1 in bats (Order: Chiroptera).  

PubMed

Rhodopsin, encoded by the gene Rhodopsin (RH1), is extremely sensitive to light, and is responsible for dim-light vision. Bats are nocturnal mammals that inhabit poor light environments. Megabats (Old-World fruit bats) generally have well-developed eyes, while microbats (insectivorous bats) have developed echolocation and in general their eyes were degraded, however, dramatic differences in the eyes, and their reliance on vision, exist in this group. In this study, we examined the rod opsin gene (RH1), and compared its evolution to that of two cone opsin genes (SWS1 and M/LWS). While phylogenetic reconstruction with the cone opsin genes SWS1 and M/LWS generated a species tree in accord with expectations, the RH1 gene tree united Pteropodidae (Old-World fruit bats) and Yangochiroptera, with very high bootstrap values, suggesting the possibility of convergent evolution. The hypothesis of convergent evolution was further supported when nonsynonymous sites or amino acid sequences were used to construct phylogenies. Reconstructed RH1 sequences at internal nodes of the bat species phylogeny showed that: (1) Old-World fruit bats share an amino acid change (S270G) with the tomb bat; (2) Miniopterus share two amino acid changes (V104I, M183L) with Rhinolophoidea; (3) the amino acid replacement I123V occurred independently on four branches, and the replacements L99M, L266V and I286V occurred each on two branches. The multiple parallel amino acid replacements that occurred in the evolution of bat RH1 suggest the possibility of multiple convergences of their ecological specialization (i.e., various photic environments) during adaptation for the nocturnal lifestyle, and suggest that further attention is needed on the study of the ecology and behavior of bats. PMID:20098620

Shen, Yong-Yi; Liu, Jie; Irwin, David M; Zhang, Ya-Ping

2010-01-01

192

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

NASA Astrophysics Data System (ADS)

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

Schaub, Yvonne; Huggel, Christian

2014-05-01

193

Increase in shock-wave sensitivity of damaged samples of TATB  

Microsoft Academic Search

Shock-wave loading conditions leading to damage of samples of plasticized TATB are described. Results of loading of the damaged\\u000a TATB samples by an explosion of a mounted initiator were recorded by pulse radiography, and they show that the shock-wave\\u000a sensitivity of the samples increases.

V. A. Komrachkov; A. D. Kovtun; Yu. M. Makarov

1999-01-01

194

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

195

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

196

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

197

Molecular systematics of aphids (Homoptera: Aphididae): new insights from the long-wavelength opsin gene  

Microsoft Academic Search

Viviparous aphids (Aphididae) constitute a monophyletic group within the Homoptera with more than 4000 extant species worldwide but higher diversity in temperate regions. Several aspects of their biology account for attention paid to this group of insects. Their plant-sap-sucking way of feeding with many species transmitting viruses to crop plants has important implications on crop management strategies. Cyclical parthenogenesis associated

Benjam??n Ortiz-Rivas; Andrés Moya; David Mart??nez-Torres

2004-01-01

198

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

199

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

200

Ciliary Photoreceptors with a Vertebrate-Type Opsin in an Invertebrate Brain  

Microsoft Academic Search

For vision, insect and vertebrate eyes use rhabdomeric and ciliary photoreceptor cells, respectively. These cells show distinct architecture and transduce the light signal by different phototransductory cascades. In the marine ragworm Platynereis, we find both cell types: rhabdomeric photoreceptor cells in the eyes and ciliary photoreceptor cells in the brain. The latter use a photopigment closely related to vertebrate rod

Detlev Arendt; Kristin Tessmar-Raible; Heidi Snyman; Adriaan W. Dorresteijn; Joachim Wittbrodt

2004-01-01

201

The opsins of the vertebrate retina: insights from structural, biochemical, and evolutionary studies  

Microsoft Academic Search

.  The vertebrate retina contains several classes of visual pigments responsible for such diverse functions as image- and nonimage-forming\\u000a vision, the entrainment of circadian cycles, and the pupilary light response. With vision being vital to the survival of many\\u000a species, the elucidation of the structural and biochemical properties of visual pigments has been the focus of a large body\\u000a of research

B. Nickle; P. R. Robinson

2007-01-01

202

Organization of the G Protein-coupled Receptors Rhodopsin and Opsin in Native Membranes  

Microsoft Academic Search

G protein-coupled receptors (GPCRs), which constitute the largest and structurally best conserved family of signal- ing molecules, are involved in virtually all physiological processes. Crystal structures are available only for the de- tergent-solubilized light receptor rhodopsin. In addition, this receptor is the only GPCR for which the presumed higher order oligomeric state in native membranes has been demonstrated (Fotiadis, D.,

Yan Liang; Dimitrios Fotiadis; Søawomir Filipek; David A. Saperstein; Krzysztof Palczewski; Andreas Engel

2003-01-01

203

Gene conversion between red and defective green opsin gene in blue cone monochromacy.  

PubMed

Blue cone monochromacy is an X-linked condition in which the function of both the red pigment gene (RCP) and the green pigment gene (GCP) is impaired. Blue cone monochromacy can be due to a red/green gene array rearrangement existing of a single red/green hybrid gene and an inactivating C203R point mutation in GCP. We describe here a family with blue cone monochromacy due to the presence of the C203R mutation in both RCP and GCP. The flanking sequences of the C203R mutation in exon 4 of RCP were characteristic for GCP, indicating that this mutation was transferred from GCP into RCP by gene conversion. PMID:8666378

Reyniers, E; Van Thienen, M N; Meire, F; De Boulle, K; Devries, K; Kestelijn, P; Willems, P J

1995-09-20

204

LWS FST: Determine and Quantify the Responses of Atmospheric/Ionospheric Composition and Temperature to Solar XUV Spectral Variability and Energetic Particles  

NASA Astrophysics Data System (ADS)

We present the research plans and preliminary results of our newly formed Living With a Star Focus Science Team plan and preliminary results. Focus Area Description: With the recent availability of comprehensive solar spectral measure-ments at X-ray and ultraviolet (XUV) wavelengths, together with upper atmospheric chemistry and transport models, quantification of the full range of solar effects on chemically active minor constituents and ion composition in the ionospherethermosphere-mesosphere (I-T-M) system is now possible. Additional solar-driven variation is caused by the energetic particle environment, ranging from auroral fluxes to galactic cosmic rays. These sources have important influences on the chemistry, energetics, and dynamics of the lower thermosphere and ionosphere (e.g., on nitric oxide and ozone) via direct energy deposition and modulation of ion-neutral fric-tional heating. Observations of neutral composition and temperature for different phases of the solar cycle and for sporadic events are available through NASA missions like the Upper At-mosphere Research Satellite (UARS) and the Thermosphere Ionosphere Mesosphere Energetics and Dynamics mission (TIMED), as well as from other space-and groundbased instruments. Observations of ionospheric electron density are available through a variety of sources. In view of these advances, models of atmospheric/ionospheric composition and energetics that fully exploit the available estimates of external energetic inputs can now be developed to more accurately quantify solar effects in the middle and upper atmosphere. We seek to determine how well our understanding of atmospheric/ionospheric processes, as incorporated in state-of-the-art models, is able to explain observed compositional and temper-ature effects in the middle and upper atmosphere caused by external energetic inputs, in order to be able to predict these effects under both normal and extreme conditions.

Talaat, Elsayed; Fuller-Rowell, Tim; Qian, Liying; Richards, Phil; Ridley, Aaron; Burns, Alan; Bernstein, Dennis; Chamberlin, Phillip; Fedrizzi, Mariangel; Hsieh, Syau-Yun; Paxton, Larry; Smith, Daniel

205

From CIE 2006 physiological model to improved age-dependent and average colorimetric observers.  

PubMed

In the context of color perception on modern wide-gamut displays with narrowband spectral primaries, we performed a theoretical analysis on various aspects of physiological observers proposed by CIE TC 1-36 (CIEPO06). We allowed certain physiological factors to vary, which was not considered in the CIEPO06 framework. For example, we analyzed that the long-wave-sensitive (LWS) or medium-wave-sensitive (MWS) peak wavelength shift in the photopigment absorption spectra, a factor not modeled in CIEPO06, contributed more toward observer variability than some of the factors considered in the model. Further, we compared the color-matching functions derived from the CIEPO06 model and the CIE 10° standard colorimetric observer to the average observer data from three distinct subgroups of Stiles-Burch observers, formed on the basis of observer ages (22-23 years, 27-29 years, and 49-50 years). The errors in predicting the x(?) and y(?) color-matching functions of the intragroup average observers in the long-wave range and in the medium-wave range, respectively, were generally more in the case of the CIEPO06 model compared to the 10° standard colorimetric observer and manifested in both spectral and chromaticity space. In contrast, the short-wave-sensitive z??(?) function of the 10° standard colorimetric observer performed poorly compared to the CIEPO06 model for all three subgroups. Finally, a constrained nonlinear optimization on the CIEPO06 model outputs showed that a peak wavelength shift of photopigment density alone could not improve the model prediction errors at higher wavelengths. As an alternative, two optimized weighting functions for each of the LWS and MWS cone photopigment densities led to significant improvement in the prediction of intra-age-group average data for both the 22-23 year and 49-50 year age groups. We hypothesize that the assumption in the CIEPO06 model that the peak optical density of visual pigments does not vary with age is false and is the source of these prediction errors at higher wavelengths. Correcting these errors in the model can lead to an improved age-dependent observer and can also help update the current CIE 10° standard colorimetric observer. Accordingly, it would reduce the discrepancies between color matches with broadband spectral primaries and color matches with narrowband spectral primaries. PMID:21979508

Sarkar, Abhijit; Autrusseau, Florent; Viénot, Françoise; Le Callet, Patrick; Blondé, Laurent

2011-10-01

206

Spatio-temporal characterization of retinal opsin gene expression during thyroid hormone-induced and natural development of rainbow trout  

Microsoft Academic Search

The abundance and spatial distribution of retinal cone photoreceptors change during thyroid hormone ~TH!-induced and natural development of rainbow trout ~Oncorhynchus mykiss!. These changes are thought to allow the fish to adapt to different photic environments throughout its life history. To date, the ontogeny of rainbow trout cone photoreceptors has been examined using physiological and morphological approaches. In this study,

KATHY VELDHOEN; W. TED ALLISON; NIK VELDHOEN; BRADLEY R. ANHOLT; CAREN C. HELBING; CRAIG W. HAWRYSHYN

2006-01-01

207

Photoreceptors in a primitive mammal, the South American opossum, Didelphis marsupialis aurita: characterization with anti-opsin immunolabeling.  

PubMed

The retinas of placental mammals appear to lack the large number and morphological diversity of cone subtypes found in diurnal reptiles. We have now studied the photoreceptor layer of a South American marsupial (Didelphis marsupialis aurita) by peanut agglutinin labeling of the cone sheath and by labeling of cone outer segments with monoclonal anti-visual pigment antibodies that have been proven to consistently label middle-to-long wavelength (COS-1) and short-wavelength (OS-2) cone subpopulations in placental mammals. Besides a dominant rod population (max. = 400,000/mm2) four subtypes of cones (max. = 3000/mm2) were identified. The outer segments of three cone subtypes were labeled by COS-1: a double cone with a principal cone containing a colorless oil droplet, a single cone with oil droplet, and another single cone. A second group of single cones lacking oil droplets was labeled by OS-2 antibody. The topography of these cone subtypes showed striking anisotropies. The COS-1 labeled single cones without oil droplets were found all over the retina and constituted the dominant population in the area centralis located in the temporal quadrant of the upper, tapetal hemisphere. The population of OS-2 labeled cones was also ubiquitous although slightly higher in the upper hemisphere (200/mm2). The COS-1 labeled cones bearing an oil droplet, including the principal member of double cones, were concentrated (800/mm2) in the inferior, non-tapetal half of the retina. The two spectral types of single cones resemble those of dichromatic photopic systems in most placental mammals. The additional set of COS-1 labeled cones is a distinct marsupial feature. The presence of oil droplets in this cone subpopulation, its absence in the area centralis, and the correlation with the non-tapetal inferior hemisphere suggest a functional specialization, possibly for mesopic conditions. Thus, sauropsid features have been retained but probably with a modified function. PMID:8924404

Ahnelt, P K; Hokoç, J N; Röhlich, P

1995-01-01

208

Acoustic mode coupling induced by shallow water nonlinear internal waves: sensitivity to environmental conditions and space-time scales of internal waves.  

PubMed

While many results have been intuited from numerical simulation studies, the precise connections between shallow-water acoustic variability and the space-time scales of nonlinear internal waves (NLIWs) as well as the background environmental conditions have not been clearly established analytically. Two-dimensional coupled mode propagation through NLIWs is examined using a perturbation series solution in which each order n is associated with nth-order multiple scattering. Importantly, the perturbation solution gives resonance conditions that pick out specific NLIW scales that cause coupling, and seabed attenuation is demonstrated to broaden these resonances, fundamentally changing the coupling behavior at low frequency. Sound-speed inhomogeneities caused by internal solitary waves (ISWs) are primarily considered and the dependence of mode coupling on ISW amplitude, range width, depth structure, location relative to the source, and packet characteristics are delineated as a function of acoustic frequency. In addition, it is seen that significant energy transfer to modes with initially low or zero energy involves at least a second order scattering process. Under moderate scattering conditions, comparisons of first order, single scattering theoretical predictions to direct numerical simulation demonstrate the accuracy of the approach for acoustic frequencies upto 400 Hz and for single as well as multiple ISW wave packets. PMID:19045637

Colosi, John A

2008-09-01

209

Age-related deterioration of rod vision in mice.  

PubMed

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, 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 with 4-month-old animals. Aging also resulted in a twofold reduction in the total level of opsin in the retina. Behavioral tests revealed that scotopic visual acuity and contrast sensitivity were decreased by twofold in aged mice, and rod ERG recordings demonstrated reduced amplitudes of both a- and b-waves. Sensitivity of aged rods determined from single-cell recordings was also decreased by 1.5-fold, corresponding to not more than 1% free opsin in these photoreceptors, and kinetic parameters of dim flash response were not altered. Notably, the rate of rod dark adaptation was unaffected by age. Thus, our results argue against age-related deficiency of 11-cis-retinal in the B6D2F1/J mouse rod visual cycle. Surprisingly, the level of cellular dark noise was increased in aged rods, providing an alternative mechanism for their desensitization. PMID:20720130

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

2010-08-18

210

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

211

A butterfly eye's view of birds  

Microsoft Academic Search

Summary The striking color patterns of butterflies and birds have long interested biologists. But how these animals see color is less well understood. Opsins are the protein components of the visual pigments of the eye. Color vision has evolved in butterflies through opsin gene duplications, through positive selection at individual opsin loci, and by the use of filtering pigments. By

Francesca D. Frentiu; Adriana D. Briscoe

2008-01-01

212

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

213

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

214

The Living with a Star Program Mission Plan  

NASA Technical Reports Server (NTRS)

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: LWS goals and program, program architecture, the solar dynamic observer, the geospace plan, the space environment testbed concept, and the heliosphere missions.

Barth, Janet; Day, John (Technical Monitor)

2001-01-01

215

Photochemical nature of parietopsin.  

PubMed

Parietopsin is a nonvisual green light-sensitive opsin closely related to vertebrate visual opsins and was originally identified in lizard parietal eye photoreceptor cells. To obtain insight into the functional diversity of opsins, we investigated by UV-visible absorption spectroscopy the molecular properties of parietopsin and its mutants exogenously expressed in cultured cells and compared the properties to those of vertebrate and invertebrate visual opsins. Our mutational analysis revealed that the counterion in parietopsin is the glutamic acid (Glu) in the second extracellular loop, corresponding to Glu181 in bovine rhodopsin. This arrangement is characteristic of invertebrate rather than vertebrate visual opsins. The photosensitivity and the molar extinction coefficient of parietopsin were also lower than those of vertebrate visual opsins, features likewise characteristic of invertebrate visual opsins. On the other hand, irradiation of parietopsin yielded meta-I, meta-II, and meta-III intermediates after batho and lumi intermediates, similar to vertebrate visual opsins. The pH-dependent equilibrium profile between meta-I and meta-II intermediates was, however, similar to that between acid and alkaline metarhodopsins in invertebrate visual opsins. Thus, parietopsin behaves as an "evolutionary intermediate" between invertebrate and vertebrate visual opsins. PMID:22303823

Sakai, Kazumi; Imamoto, Yasushi; Su, Chih-Ying; Tsukamoto, Hisao; Yamashita, Takahiro; Terakita, Akihisa; Yau, King-Wai; Shichida, Yoshinori

2012-03-01

216

Photochemical Nature of Parietopsin  

PubMed Central

Parietopsin is a non-visual green-light-sensitive opsin closely related to vertebrate visual opsins, and was originally identified in lizard parietal-eye photoreceptor cells. To obtain insight into the functional diversity of opsins, we investigated by UV-visible absorption spectroscopy the molecular properties of parietopsin and its mutants exogenously expressed in cultured cells, and compared to vertebrate and invertebrate visual opsins. Our mutational analysis revealed that the counterion in parietopsin is the glutamic acid (Glu) in the second extracellular loop, corresponding to Glu181 in bovine rhodopsin. This arrangement is characteristic of invertebrate rather than vertebrate visual opsins. The photosensitivity and the molar extinction coefficient of parietopsin were also lower than those of vertebrate visual opsins, features likewise characteristic of invertebrate visual opsins. On the other hand, irradiation of parietopsin yielded meta-I, meta-II, and meta-III intermediates after batho- and lumi-intermediates, similar to vertebrate visual opsins. The pH-dependent equilibrium profile between meta-I and meta-II intermediates was, however, similar to that between acid and alkaline metarhodopsins in invertebrate visual opsins. Thus, parietopsin behaves as an “evolutionary intermediate” between invertebrate and vertebrate visual opsins.

Sakai, Kazumi; Imamoto, Yasushi; Su, Chih-Ying; Tsukamoto, Hisao; Yamashita, Takahiro; Terakita, Akihisa; Yau, King-Wai; Shichida, Yoshinori

2012-01-01

217

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

218

Ectopic Expression of Ultraviolet-Rhodopsins in the Blue Photoreceptor Cells of Drosophila: Visual Physiology and Photochemistry of Transgenic Animals  

Microsoft Academic Search

We have generated transgenic flies expressing R7 cell-spe- cific opsins in the major class of photoreceptor cells of the Drosophila retina and characterized their spectral properties using high-resolution microspectrophotometry and sensitiv- ity recordings. We show that the Rh3 and Rh4 opsin genes encode UV-sensitive opsins with similar spectral properties &ax = 345 nm and 375 nm), and that Rh3 corresponds

K. Kirschfeld; D. Mismer; G. M. Rubin; D. P. Smith; M. Socolich

219

Molecular evolution of color vision of zebra finch  

Microsoft Academic Search

We have isolated and sequenced the RH1Tg, RH2Tg, SWS2Tg, and LWSTg opsin cDNAs from zebra finch retinas. Upon binding to 11-cis-retinal, these opsins regenerate the corresponding photosensitive molecules, visual pigments. The absorption spectra of visual pigments have a broad bell shape, with the peak being called ?max. Previously, SWS1Tg opsin cDNA was isolated from zebra finch retinal RNA, expressed in

Shozo Yokoyama; Nathan S Blow; F. Bernhard Radlwimmer

2000-01-01

220

TARGETED RESEARCH AND TECHNOLOGY WITHIN NASA'S LIVING WITH A STAR PROGRAM.  

SciTech Connect

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, and data analysis necessary to enable an integrated, system-wide picture of Sun-Earth connection science with societal relevance. Recognizing the central and essential role that TR&T would have for the success of the LWS initiative, the LWS Science Architecture Team (SAT) recommended that a Science Definition Team (SDT), with the same status as a flight mission definition team, be formed to design and coordinate a TR&T program having prioritized goals and objectives that focused on practical societal benefits. This report details the SDT recommendations for the TR&T program.

Gosling, J. T.; Antiochos, Spiro; Baker, Kile; Bellaire, Paul; Blake, Bern; Crowley, Geoff; Eddy, Jack; Goodrich, Charles; Gopalswamy, Nat; Hesse, Michael; Hurlburt, Neal; Jackman, Charles; Kozyra, Janet; Labonte, Barry; Lean, Judith; Linker, Jon; Mazur, Joe; Onsager, Terry; Sibeck, David

2003-07-10

221

Evolving the Living With a Star Data System Definition  

NASA Astrophysics Data System (ADS)

NASA's Living With a Star (LWS) Program is a space weather-focused and applications-driven research program. The LWS Program is soliciting input from the solar, space physics, space weather, and climate science communities to develop a system that enables access to science data associated with these disciplines, and advances the development of discipline and interdisciplinary findings. The LWS Program will implement a data system that builds upon the existing and planned data capture, processing, and storage components put in place by individual spacecraft missions and also inter-project data management systems, including active and deep archives, and multi-mission data repositories. It is technically feasible for the LWS Program to integrate data from a broad set of resources, assuming they are either publicly accessible or allow access by permission. The LWS Program data system will work in coordination with spacecraft mission data systems and science data repositories, integrating their holdings using a common metadata representation. This common representation relies on a robust metadata definition that provides journalistic and technical data descriptions, plus linkages to supporting data products and tools. The LWS Program intends to become an enabling resource to PIs, interdisciplinary scientists, researchers, and students facilitating both access to a broad collection of science data, as well as the necessary supporting components to understand and make productive use of these data. For the LWS Program to represent science data that are physically distributed across various ground system elements, information will be collected about these distributed data products through a series of LWS Program-created agents. These agents will be customized to interface or interact with each one of these data systems, collect information, and forward any new metadata records to a LWS Program-developed metadata library. A populated LWS metadata library will function as a single point-of-contact that serves the entire science community as a first stop for data availability, whether or not science data are physically stored in an LWS-operated repository. Further, this metadata library will provide the user access to information for understanding these data including descriptions of the associated spacecraft and instrument, data format, calibration and operations issues, links to ancillary and correlative data products, links to processing tools and models associated with these data, and any corresponding findings produced using these data. The LWS may also support an active archive for solar, space physics, space weather, and climate data when these data would otherwise be discarded or archived off-line. This archive could potentially serve also as a data storage backup facility for LWS missions. The plan for the LWS Program metadata library is developed based upon input received from the solar and geospace science communities; the library's architecture is based on existing systems developed for serving science metadata. The LWS Program continues to seek constructive input from the science community, examples of both successes and failures in dealing with science data systems, and insights regarding the obstacles between the current state-of-the-practice and this vision for the LWS Program metadata library.

Otranto, J. F.; Dijoseph, M.

2003-12-01

222

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

NASA Technical Reports Server (NTRS)

Targeted Research & Technology (TR&T) 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, and data analysis necessary to enable an integrated, system-wide picture of Sun-Earth connection science with societal relevance. Recognizing the central and essential role that TR&T would have for the success of the LWS initiative, the LWS Science Architecture Team (SAT) recommended that a Science Definition Team (SDT), with the same status as a flight mission definition team, be formed to design and coordinate a TR&T program having prioritized goals and objectives that focused on practical societal benefits. This report details the SDT recommendations for the TR&T program.

Antiochos, Spiro; Baker, Kile; Bellaire, Paul; Blake, Bern; Crowley, Geoff; Eddy, Jack; Goodrich, Charles; Gopalswamy, Nat; Gosling, Jack; Hesse, Michael

2004-01-01

223

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

NASA Technical Reports Server (NTRS)

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, and data analysis necessary to enable an integrated, system-wide picture of Sun-Earth connection science with societal relevance. Recognizing the central and essential role that TR&T would have for the success of the LWS initiative, the LWS Science Architecture Team (SAT) recommended that a Science Definition Team (SDT), with the same status as a flight mission definition team, be formed to design and coordinate a TR&T program having prioritized goals and objectives that focused on practical societal benefits. This report details the SDT recommendations for the TR&T program.

Hesse, Michael

2003-01-01

224

Identification and characterization of a protostome homologue of peropsin from a jumping spider.  

PubMed

Peropsin, a member of the opsin family, has characteristics of two functionally distinct opsin-groups, that is, amino acid residues conserved among opsins for light-sensing and a retinal-photoisomerase-like molecular property. Although such a bilateral feature of peropsin seems to be important for understanding the diversity of the opsin family, previous studies have been limited to higher deuterostome, vertebrate and amphioxus peropsins. Here, we report a protostome peropsin homologue from a jumping spider. We found a spider opsin that shares amino acid homology and conserved amino acid residues with known peropsins. The spider opsin-based pigment heterologously expressed in cultured cells exhibited photoisomerase-like isomerization characteristics and a bistable nature. Based on the characteristics of both the amino acid homology and its photochemical properties, we concluded that the spider opsin is the first protostome peropsin homologue. These results show that peropsin existed before the deuterostome-protostome split like other members of the opsin family. In addition, the spider peropsin was localized to non-visual cells in the retina, and fluorescence from reduced retinal chromophore was also observed in the region where peropsin was localized. These findings provide the first demonstration that the peropsin can form a photosensitive pigment in vivo and underlie non-visual function. PMID:19960196

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

2010-01-01

225

Evolution and Mechanism of Spectral Tuning of Blue-Absorbing Visual Pigments in Butterflies  

Microsoft Academic Search

The eyes of flower-visiting butterflies are often spectrally highly complex with multiple opsin genes generated by gene duplication, providing an interesting system for a comparative study of color vision. The Small White butterfly, Pieris rapae, has duplicated blue opsins, PrB and PrV, which are expressed in the blue (?max = 453 nm) and violet receptors (?max = 425 nm), respectively.

Motohiro Wakakuwa; Akihisa Terakita; Mitsumasa Koyanagi; Doekele G. Stavenga; Yoshinori Shichida; Kentaro Arikawa; Eric James Warrant

2010-01-01

226

Site of Attachment of Retinal in Rhodopsin  

Microsoft Academic Search

On illumination, rhodopsin passes through several unstable intermediates to a final mixture of retinal and opsin. One of these intermediates, metarhodopsin II, can be reduced by sodium borohydride to bind irreversibly the prosthetic group retinal to opsin in secondary amino linkage.

Deric Bownds

1967-01-01

227

Morphological, Physiological, and Biochemical Changes in Rhodopsin Knockout Mice  

Microsoft Academic Search

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

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

1999-01-01

228

Income, Assets, and Poverty: Older Women in Comparative Perspective  

Microsoft Academic Search

We analyze the economic well?being of older women in cross?national perspective, comparing the United States with four other high?income countries: the United Kingdom, Germany, Italy, and Sweden. We report some of the first findings based on microdata from a new source, the Luxembourg Wealth Study (LWS). The LWS, a project within the larger Luxembourg Income Study (LIS), is a database

Janet C. Gornick; Teresa Munzi; Eva Sierminska; Timothy M. Smeeding

2009-01-01

229

Excitation of Langmuir waves by the lower energy cutoff behavior of power-law electrons  

NASA Astrophysics Data System (ADS)

Langmuir waves (LWs), which are believed to play a crucial role in the plasma emission of solar radio bursts, can be excited by streaming instability of energetic electron beams. However, solar hard X-ray observations imply that the energetic flare electrons usually have a power-law energy distribution with a lower energy cutoff. In this paper, we investigate LWs driven by the power-law electrons. The results show that power-law electrons with the steepness cutoff behavior can excite LWs effectively because of the population inversion distribution below the cutoff energy ($E_c$). The growth rate of LWs increases with the steepness index ($\\delta$) and decreases with the power-law index ($\\alpha$). The wave number of the fastest growing LWs ($k\\lambda_D$), decreases with the characteristic velocity of the power-law electrons ($v_{c}=\\sqrt{2E_{c}/m_{e}}$) and increases with the thermal velocity of ambient electrons ($v_T$). This can be helpful for us to understand better the physics of LWs and the dynamics of energetic electron beams in space and astrophysical plasmas.

Tang, Jianfei; Wu, Dejin; Zhao, Guoqing; Chen, Ling; Tan, Chengming

2014-06-01

230

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

231

Derivation of Human Differential Photoreceptor-like Cells from the Iris by Defined Combinations of CRX, RX and NEUROD  

PubMed Central

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.

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

2012-01-01

232

Evolution of cichlid vision via trans-regulatory divergence  

PubMed Central

Background Phenotypic evolution may occur through mutations that affect either the structure or expression of protein-coding genes. Although the evolution of color vision has historically been attributed to structural mutations within the opsin genes, recent research has shown that opsin regulatory mutations can also tune photoreceptor sensitivity and color vision. Visual sensitivity in African cichlid fishes varies as a result of the differential expression of seven opsin genes. We crossed cichlid species that express different opsin gene sets and scanned their genome for expression Quantitative Trait Loci (eQTL) responsible for these differences. Our results shed light on the role that different structural, cis-, and trans-regulatory mutations play in the evolution of color vision. Results We identified 11 eQTL that contribute to the divergent expression of five opsin genes. On three linkage groups, several eQTL formed regulatory “hotspots” associated with the expression of multiple opsins. Importantly, however, the majority of the eQTL we identified (8/11 or 73%) occur on linkage groups located trans to the opsin genes, suggesting that cichlid color vision has evolved primarily via trans-regulatory divergence. By modeling the impact of just two of these trans-regulatory eQTL, we show that opsin regulatory mutations can alter cichlid photoreceptor sensitivity and color vision at least as much as opsin structural mutations can. Conclusions Combined with previous work, we demonstrate that the evolution of cichlid color vision results from the interplay of structural, cis-, and especially trans-regulatory loci. Although there are numerous examples of structural and cis-regulatory mutations that contribute to phenotypic evolution, our results suggest that trans-regulatory mutations could contribute to phenotypic divergence more commonly than previously expected, especially in systems like color vision, where compensatory changes in the expression of multiple genes are required in order to produce functional phenotypes.

2012-01-01

233

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

PubMed Central

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

Jimenez-Lopez, Manuel; Alburquerque-Bejar, Juan J.; Nieto-Lopez, Leticia; Garcia-Ayuso, Diego; Villegas-Perez, Maria P.; Vidal-Sanz, Manuel; Agudo-Barriuso, Marta

2014-01-01

234

Role of secondary long wavelength structures in the saturation of electron temperature gradient driven turbulence  

SciTech Connect

The dynamics of secondary long wavelength structures (LWSs) in electron temperature gradient (ETG) driven turbulence are investigated by performing gyrofluid simulations and modeling analyses in a slab geometry with an emphasis of the underlying nonlinear interaction processes. It is shown that the back-reaction of the secondary LWS on the ambient fluctuations essentially contributes to saturating ETG instability and limiting the electron transport. The LWS is nonlinearly generated mainly through the beating of the most unstable ETG modes, even a weak modulation instability. The back-reaction is identified as the enhanced stabilization of the ETG modes due to the streamer-type feature of the LWS, which dominantly produces a local poloidal mode coupling among unstable and highly damped spectral components to form a global mode, besides the suppression effect of the LWS due to the radial shearing decorrelation and/or the radial mode coupling. Finally, the correspondence between the LWS in the slab model and the quasimode observed in toroidal ETG simulation [Z. Lin et al., Phys. Plasmas 12, 056125 (2005)] and the importance of the nonlinear mode coupling in the multiscale turbulence interaction are discussed.

Li Jiquan [Department of Fundamental Energy, Kyoto University, 611-0011 Gokasho, Uji (Japan); Institute for Fusion Theory and Simulation, Zhejiang University, Hangzhou (China); Kishimoto, Y. [Department of Fundamental Energy, Kyoto University, 611-0011 Gokasho, Uji (Japan)

2008-11-15

235

The photochemical determinants of color vision  

PubMed Central

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

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

2014-01-01

236

Evolution of Vision  

Microsoft Academic Search

The evolution of photoreception, giving rise to eye, offers a kaleidoscopic view on selection acting at both the organ and\\u000a molecular levels. The molecular level is mainly considered in the lecture. The greatest progress to date has been made in\\u000a relation to the opsin visual pigments. Opsins appeared before eyes did. Two- and three-dimensional organization for rhodopsin\\u000a in the rod

Mikhail Ostrovsky

2008-01-01

237

Molecular evolution of vertebrate visual pigments  

Microsoft Academic Search

Dramatic improvement of our understanding of the genetic basis of vision was brought by the molecular characterization of the bovine rhodopsin gene and the human rhodopsin and color opsin genes (Nathans and Hogness, 1983; Nathans et al., 1984, 1986a,b). The availability of cDNA clones from these studies has facilitated the isolation of retinal and nonretinal opsin genes and cDNA clones

Shozo Yokoyama

2000-01-01

238

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

239

Visual Pigment Coexpression in All Cones of Two Rodents, the Siberian Hamster, and the Pouched Mouse  

Microsoft Academic Search

PURPOSE. To decide whether the identical topography of short- and middle-wavelength cone photoreceptors in two species of rodents reflects the presence of both opsins in all cone cells. METHODS. Double-label immunocytochemistry using antibodies directed against short-wavelength (S)- and middle- to long- wavelength (M\\/L)-sensitive opsin were used to determine the presence of visual pigments in cones of two species of rodents,

Akos Lukats; Ouria Dkhissi-Benyahya; Zsuzsanna Szepessy; Pal Rohlich; Bela Võ ´ gh; Nigel C. Bennett; Howard M. Cooper; Agoston Szel

2002-01-01

240

RPE65 Is Essential for the Function of Cone Photoreceptors in NRL-Deficient Mice  

Microsoft Academic Search

PURPOSE. Phototransduction in cones is initiated by the bleaching of their visual pigment, which comprises a protein component— cone opsin—and a vitamin A derivative—11-cis retinal. Little is known about the source of 11-cis retinal for cones. In the current study, neural retina leucine zipper-deficient (Nrl\\/) and rod opsin (Rho\\/)-deficient mice were used, two mouse models that have been described as

Andreas Wenzel; Johannes von Lintig; Vitus Oberhauser; Naoyuki Tanimoto; Christian Grimm; Mathias W. Seeliger

2007-01-01

241

Tautomeric Forms of Metarhodopsin  

Microsoft Academic Search

Light isomerizes the chromophore of rhodopsin, ll-cis retinal (formerly retinene), to the all-trans configuration. This introduces a succession of unstable intermediates--pre-lumirhodopsin, lumirhodopsin, metarhodopsin --in which all-trans retinal is still attached to the chromophoric site on opsin. Finally, retinal is hydrolyzed from opsin. The present experiments show that metarhodopsin exists in two tautomeric forms, metarhodopsins I and II, with ),m~ 478

ROWENA G. MATTHEWS; RUTH HUBBARD; PAUL K. BROWN; GEORGE WALD

1963-01-01

242

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

243

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

244

Human cone visual pigment deletions spare sufficient photoreceptors to warrant gene therapy.  

PubMed

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

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

2013-12-01

245

NASA space shuttle lightweight seat  

NASA Technical Reports Server (NTRS)

The Space Shuttle Lightweight Seat-Mission Specialist (LWS-MS) is a crew seat for the mission specialists who fly aboard the Space Shuttle. The LWS-MS is a lightweight replacement for the mission specialist seats currently flown on the Shuttle. Using state-of-the-art analysis techniques, a team of NASA and Lockheed engineers from the Johnson Space Center (JSC) designed a seat that met the most stringent requirements demanded of the new seats by the Shuttle program, and reduced the weight of the seats by 52%.

Hansen, Chris; Jermstad, Wayne; Lewis, James; Colangelo, Todd

1996-01-01

246

Structure and function in rhodopsin: packing of the helices in the transmembrane domain and folding to a tertiary structure in the intradiscal domain are coupled.  

PubMed

A previous study of the retinitis pigmentosa mutation L125R and two designed mutations at this site, L125A and L125F, showed that these mutations cause partial or total misfolding of the opsins expressed in COS cells from the corresponding mutant opsin genes. We now report on expression and characterization of the opsins from the following retinitis pigmentosa mutants in the transmembrane domain of rhodopsin that correspond to six of the seven helices: G51A and G51V (helix A), G89D (helix B), A164V (helix D), H211P (helix E), P267L and P267R (helix F), and T297R (helix G). All the mutations caused partial misfolding of the opsins as observed by the UV/visible absorption characteristics and by separation of the expressed opsins into fractions that bound 11-cis-retinal to form the corresponding mutant rhodopsins and those that did not bind 11-cis-retinal. Further, all the mutant rhodopsins prepared from the above mutants, except for G51A, showed strikingly abnormal bleaching behavior with abnormal metarhodopsin II photointermediates. The results show that retinitis pigmentosa mutations in every one of the transmembrane helices can cause misfolding of the opsin. Therefore, on the basis of these and previous results, we conclude that defects in the packing of the transmembrane helices resulting from these mutations are relayed to the intradiscal domain, where they cause misfolding of the opsin by inducing the formation of a disulfide bond other than the native Cys-110---Cys-187 disulfide bond. Thus, there is coupling between packing of the helices in the transmembrane domain and folding to a tertiary structure in the intradiscal domain. PMID:9380676

Hwa, J; Garriga, P; Liu, X; Khorana, H G

1997-09-30

247

Structure and function in rhodopsin: Packing of the helices in the transmembrane domain and folding to a tertiary structure in the intradiscal domain are coupled*  

PubMed Central

A previous study of the retinitis pigmentosa mutation L125R and two designed mutations at this site, L125A and L125F, showed that these mutations cause partial or total misfolding of the opsins expressed in COS cells from the corresponding mutant opsin genes. We now report on expression and characterization of the opsins from the following retinitis pigmentosa mutants in the transmembrane domain of rhodopsin that correspond to six of the seven helices: G51A and G51V (helix A), G89D (helix B), A164V (helix D), H211P (helix E), P267L and P267R (helix F), and T297R (helix G). All the mutations caused partial misfolding of the opsins as observed by the UV/visible absorption characteristics and by separation of the expressed opsins into fractions that bound 11-cis-retinal to form the corresponding mutant rhodopsins and those that did not bind 11-cis-retinal. Further, all the mutant rhodopsins prepared from the above mutants, except for G51A, showed strikingly abnormal bleaching behavior with abnormal metarhodopsin II photointermediates. The results show that retinitis pigmentosa mutations in every one of the transmembrane helices can cause misfolding of the opsin. Therefore, on the basis of these and previous results, we conclude that defects in the packing of the transmembrane helices resulting from these mutations are relayed to the intradiscal domain, where they cause misfolding of the opsin by inducing the formation of a disulfide bond other than the native Cys-110—Cys-187 disulfide bond. Thus, there is coupling between packing of the helices in the transmembrane domain and folding to a tertiary structure in the intradiscal domain.

Hwa, John; Garriga, Pere; Liu, Xun; Khorana, H. Gobind

1997-01-01

248

Multiscale Deterministic Wave Modeling with Wind Input and Wave Breaking Dissipation.  

National Technical Information Service (NTIS)

The primary focus of this research is to use large-eddy simulation (LES) and large-wave simulation (LWS) to obtain improved physical understanding of wind-wave-ocean interactions, based on which we aim to develop effective models of wind input and whiteca...

L. Shen

2007-01-01

249

Far-infrared spectroscopic images of M83  

Microsoft Academic Search

We have mapped the nearby face on barred spiral galaxy, M83 in the bright [CII] 158 mum, [OI] 63 and 146 mum, [NII] 122 mum, and [OIII] 88 mum fine-structure lines with the Long Wavelength Spectrometer (LWS) on ISO. The maps are nearly fully sampled, and cover the inner 6.75' x 6' region - essentially the entire optical disk. We

G. J. Stacey; M. R. Swain; C. M. Bradford; M. J. Barlow; P. Cox; J. Fischer; S. D. Lord; M. L. Luhman; N. Q. Rieu; H. A. Smith; S. J. Unger; M. G. Wolfire

1999-01-01

250

When are driven Langmuir waves resonant?  

NASA Astrophysics Data System (ADS)

We are taught that small amplitude plasma waves are associated with zeroes of the linear dielectric function, ?0( k,? ), in the complex ? plane and that, for Langmuir waves (LW) in particular, Landau damping diminishes their response to an external potential as k?D increases. But finite amplitude LWs trap electrons, thus reducing Landau damping (O'Neil, Phys. Fluids 8 (1965)). Do trapping effects strengthen the response indefinitely with increase of LW amplitude or is there a k?D dependent limit? One-dimensional (1D), small amplitude theory (Holloway and Dorning, Phys. Rev. A44 (1991)) showed that thermal plasma supports traveling LWs if k?D.3ex<˜x 0.53, consistent with LW resonance, Re[ ?0( k,? ) ]=0 for real ?. Resonance is not possible for larger k?D. A model of 1D finite amplitude traveling LWs (Rose and Russell, Phys. Plasmas 8 (2001)) showed that increase of wave amplitude leads to a decrease of the resonant k?D range, and diminished SRS gain rate (Rose and Yin, Phys Plasmas 15 (2008)). Results of 2D Vlasov simulations will be presented that manifest similar behavior: there is an amplitude limit to driven LWs, beyond which the LW response to an external potential is nonresonant. This limit decreases as k?D approaches 0.5.

Rose, Harvey

2011-11-01

251

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

PubMed Central

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

Yokoyama, S; Radlwimmer, F B

2001-01-01

252

Near infrared imaging and {o I} spectroscopy of IC 443 using two micron all sky survey and infrared space observatory  

NASA Technical Reports Server (NTRS)

We present near-infrared J (1.25 mum), H (1.65 mum), and K-s (2.17 mum) imaging of the entire supernova remnant IC 443 from the Two Micron All Sky Survey (2MASS), and Infrared Space Observatory (ISO) LWS observations of [O I] for 11 positions in the northeast.

Rho, J.; Jarrett, T. H.; Cutri, C. M.; Reach, W. T.

2001-01-01

253

The Living With a Star Space Environment Testbeds  

Microsoft Academic Search

The Living With a Star (LWS) Space Environment Testbeds (SET) are a series of projects that contain investigations that collect data in space and use it to provide products that improve the engineering approach to accommodate and\\/or mitigate the effects of solar variability on spacecraft design and operations. The improvements reduce requirements for design and operations margins to account for

D. Brewer; J. Barth; K. Label

2002-01-01

254

The effects of solar variability on technology: objectives of NASA's Space Environment Testbed  

Microsoft Academic Search

The Space Environment Testbed (SET) is a complementary element of NASA's new Living With a Star (LWS) Program. This program is designed to help humankind understand and successfully exist with the Sun and its variability throughout the solar cycle. The SET element is a series of flight testbeds focused on this variability and its effects on space system technology, as

Kenneth A. LaBel; Janet L. Barth; Dana Brewer; Billy Kaufmann; Regan Howard; G. Giffin; C. Marshall; P. Marshall

2001-01-01

255

Comparative life cycle analysis for green façades and living wall systems  

Microsoft Academic Search

Greening the building envelope focusing on green façades with vegetation is a good example of a new construction practice. Plants and partly growing materials in case of living wall systems (LWS) have a number of functions that are beneficial, for example: increasing the biodiversity and ecological value, mitigation of urban heat island effect, outdoor and indoor comfort, insulating properties, improvement

Marc Ottelé; Katia Perini; A. L. A. Fraaij; E. M. Haas; R. Raiteri

2011-01-01

256

Fermentation of liquid coproducts and liquid compound diets: Part 1. Effects on chemical composition during 6-day storage period  

Microsoft Academic Search

The effects of a 6-day storage period on changes in dry matter, crude ash, crude protein, true protein, crude fat, starch, soluble starch, sugar and lactose of three liquid coproducts and two liquid compound diets were studied. The three liquid coproducts studied were: liquid wheat starch (LWS), mashed potato steam peel (PSP) and cheese whey (CW), and the two liquid

R. H. J. Scholten; M. M. J. A. Rijnen; J. W. Schrama; H. Boer; P. C. Vesseur; Hartog den L. A; C. M. C. Van Der Peet-Schwering; M. W. A. Verstegen

2001-01-01

257

The Radiation Belt Storm Probes (RBSP): Using A Fundamental Physics Mission to Support Practical Applications  

Microsoft Academic Search

This presentation provides an overview of the Living With a Star (LWS) Radiation Belt Storm Probes (RBSP) mission and its planned contributions to space weather activities. The RBSP mission targets Earth's space radiation belts that comprise multiple components of high energy, penetrating charged particles. These belts are hazardous to spacecraft and astronauts alike and are controlled by dynamic processes that

N. J. Fox; B. H. Mauk; M. Weiss; R. J. Barnes; R. Kessel; D. G. Sibeck

2010-01-01

258

The physical structure of high-mass star-forming cores  

Microsoft Academic Search

We present models of the temperature and density structure of the envelopes of ten deeply embedded massive stars associated with ultracompact HII regions. Constraints come from 60-1300 mum photometry including ISO-LWS spectra, maps at 450 and 850 mum , and CS emission line data. Radial profiles extracted from the maps after removing neighbouring sources were modelled taking the chopping process

J. Hatchell

2003-01-01

259

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...

260

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...

261

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

2013-07-01

262

Evolution and mechanism of spectral tuning of blue-absorbing visual pigments in butterflies.  

PubMed

The eyes of flower-visiting butterflies are often spectrally highly complex with multiple opsin genes generated by gene duplication, providing an interesting system for a comparative study of color vision. The Small White butterfly, Pieris rapae, has duplicated blue opsins, PrB and PrV, which are expressed in the blue (?(max)?=?453 nm) and violet receptors (?(max)?=?425 nm), respectively. To reveal accurate absorption profiles and the molecular basis of the spectral tuning of these visual pigments, we successfully modified our honeybee opsin expression system based on HEK293s cells, and expressed PrB and PrV, the first lepidopteran opsins ever expressed in cultured cells. We reconstituted the expressed visual pigments in vitro, and analysed them spectroscopically. Both reconstituted visual pigments had two photointerconvertible states, rhodopsin and metarhodopsin, with absorption peak wavelengths 450 nm and 485 nm for PrB and 420 nm and 482 nm for PrV. We furthermore introduced site-directed mutations to the opsins and found that two amino acid substitutions, at positions 116 and 177, were crucial for the spectral tuning. This tuning mechanism appears to be specific for invertebrates and is partially shared by other pierid and lycaenid butterfly species. PMID:21124838

Wakakuwa, Motohiro; Terakita, Akihisa; Koyanagi, Mitsumasa; Stavenga, Doekele G; Shichida, Yoshinori; Arikawa, Kentaro

2010-01-01

263

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

264

NASA s Contribution To International Living With A Star  

NASA Astrophysics Data System (ADS)

The Living With a Star (LWS) program seeks to develop the scientific understanding necessary to effectively address those aspects of the connected Sun-Earth system that directly affect life and society. It is the study of the physics of solar variability and its effects. Why do we care? We have increased dependence on space-based systems, soon a permanent presence of humans in Earth orbit, and eventually human voyages beyond Earth. Solar variability can affect space systems, human space flight, electric power grids, GPS signals, high frequency radio communications, long range radar, mi- croelectronics and humans in high altitude spacecraft, and terrestrial climate. Prudence demands that we fully understand the space environment affecting these systems. In addition, we should fully understand both natural and anthropogenic causes of global climate change. To address these questions NASA formulated two groups of mission scenarios in the LWS Space Weather Research Network: (a) solar dynamics elements (Solar Dynamics Observatory/Sentinels) that observe the Sun and track disturbances originating there and (b) geospace dynamics elements (Geospace Missions Network) consisting of con- stellations of small satellites located in key regions around the Earth to measure down- stream effects. A coherent effort to develop analytic and data reduction techniques targeting scientific problems relevant to utilitarian needs are being addressed by the Targeted Research &Technology (TR&T) program. Activities in this area not only will allow development of new theories and improvements of models, but also will form the basis for new observational initiatives to be undertaken later in the program. Finally, Space Environment Testbeds is dedicated towards research on instruments &spacecraft systems for future missions in severe radiation environments. Although originally a U.S. initiative, the problems that LWS addresses are global in nature. Thus, it is recognized that LWS will be more successful if it features open data and encourages participation by national and international partners. The latest status of the LWS program in the U.S. will be reported.

Guhathakurta, M.

265

Binding specificity of retinal analogs to photoactivated visual pigments suggest mechanism for fine-tuning GPCR-ligand interactions.  

PubMed

11-cis-retinal acts as an inverse agonist stabilizing the inactive conformation of visual pigments, and upon photoactivation, it isomerizes to all-trans-retinal, initiating signal transduction. We have analyzed opsin regeneration with retinal analogs for rhodopsin and red cone opsin. We find differential binding of the analogs to the receptors after photobleaching and a dependence of the binding kinetics on the oligomerization state of the protein. The results outline the sensitivity of retinal entry to the binding pocket of visual receptors to the specific conformation adopted by the receptor and by the molecular architecture defined by specific amino acids in the binding pocket and the retinal entry site, as well as the topology of the retinal analog. Overall, our findings highlight the specificity of the ligand-opsin interactions, a feature that can be shared by other G-protein-coupled receptors. PMID:24560606

Srinivasan, Sundaramoorthy; Ramon, Eva; Cordomí, Arnau; Garriga, Pere

2014-03-20

266

Cone visual pigments.  

PubMed

Cone visual pigments are visual opsins that are present in vertebrate cone photoreceptor cells and act as photoreceptor molecules responsible for photopic vision. Like the rod visual pigment rhodopsin, which is responsible for scotopic vision, cone visual pigments contain the chromophore 11-cis-retinal, which undergoes cis-trans isomerization resulting in the induction of conformational changes of the protein moiety to form a G protein-activating state. There are multiple types of cone visual pigments with different absorption maxima, which are the molecular basis of color discrimination in animals. Cone visual pigments form a phylogenetic sister group with non-visual opsin groups such as pinopsin, VA opsin, parapinopsin and parietopsin groups. Cone visual pigments diverged into four groups with different absorption maxima, and the rhodopsin group diverged from one of the four groups of cone visual pigments. The photochemical behavior of cone visual pigments is similar to that of pinopsin but considerably different from those of other non-visual opsins. G protein activation efficiency of cone visual pigments is also comparable to that of pinopsin but higher than that of the other non-visual opsins. Recent measurements with sufficient time-resolution demonstrated that G protein activation efficiency of cone visual pigments is lower than that of rhodopsin, which is one of the molecular bases for the lower amplification of cones compared to rods. In this review, the uniqueness of cone visual pigments is shown by comparison of their molecular properties with those of non-visual opsins and rhodopsin. This article is part of a Special Issue entitled: Retinal Proteins - You can teach an old dog new tricks. PMID:24021171

Imamoto, Yasushi; Shichida, Yoshinori

2014-05-01

267

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

268

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

PubMed Central

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

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

2010-01-01

269

Phototransduction Motifs and Variations  

PubMed Central

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

Yau, King-Wai; Hardie, Roger C.

2010-01-01

270

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

271

An ISO survey of possible water and hydroxyl IRASER transitions towards the star-forming regions W49, W3(OH) and Sgr B2M  

NASA Astrophysics Data System (ADS)

We report ISO LWS observations towards the star-forming regions W49N, W3(OH) and Sgr B2M in LWS04 mode (high-resolution Fabry-Perot scans). Possible far-infrared laser emission was detected in a water line at 133.55?m towards W49N, but the spectral resolution was inadequate to establish firmly the nature of the emission. An additional water line was marginally detected in absorption at the 3? level, also towards W49N, at 169.74?m. No OH lines were detected towards Sgr B2M or W3(OH) at either 134.83 or 135.95?m, either in emission or in absorption.

Gray, M. D.; Yates, J. A.

1999-12-01

272

Effect of 24 months of recombinant growth hormone on height and body proportions in SHOX haploinsufficiency.  

PubMed

Leri-Weill syndrome (LWS) is a skeletal dysplasia with mesomelic short stature, bilateral Madelung deformity (BMD) and SHOX (short stature homeobox-containing gene) haploinsufficiency. The effect of 24 months of recombinant human growth hormone (rhGH) therapy on the stature and BMD of two females with SHOX haploinsufficiency (demonstrated by fluorescence in situ hybridisation) and LWS was evaluated. Both patients demonstrated an increase in height standard deviation score (SDS) and height velocity SDS over the 24 months of therapy. Patient 1 demonstrated a relative increase in arm-span and upper segment measurements with rhGH while patient 2 demonstrated a relative increase in lower limb length. There was appropriate advancement of bone age, no adverse events and no significant deterioration in BMD. In this study, 24 months of rhGH was a safe and effective therapy for the disproportionate short stature of SHOX haploinsufficiency, with no clinical deterioration of BMD. PMID:14513876

Munns, C F J; Berry, M; Vickers, D; Rappold, G A; Hyland, V J; Glass, I A; Batch, J A

2003-09-01

273

ANTENNA RADIATION NEAR THE LOCAL PLASMA FREQUENCY BY LANGMUIR WAVE EIGENMODES  

SciTech Connect

Langmuir waves (LWs) in the solar wind are generated by electron beams associated with solar flares, interplanetary shock fronts, planetary bow shocks, and magnetic holes. In principle, LWs localized as eigenmodes of density fluctuations can emit electromagnetic (EM) radiation by an antenna mechanism near the local plasma frequency f{sub p} and twice the local plasma frequency. In this work, analytic expressions are derived for the radiated electric and magnetic fields and power generated near f{sub p} by LW eigenmodes. The EM wave power emitted near f{sub p} is predicted as a function of the eigenmode length scale L, maximum electric field, driving electron beam speed, and the ambient plasma density and temperature. The escape to a distant observer of f{sub p} radiation from a localized Langmuir eigenmode is also briefly explored as a function of the plasma conditions.

Malaspina, David M. [Laboratory for Atmospheric and Space Physics, University of Colorado, Boulder, CO 80303 (United States); Cairns, Iver H. [School of Physics, University of Sydney, New South Wales 2006 (Australia); Ergun, Robert E., E-mail: David.Malaspina@lasp.colorado.edu, E-mail: cairns@physics.usyd.edu.au, E-mail: ree@lasp.colorado.edu [Laboratory for Atmospheric and Space Physics, Department of Astrophysical and Planetary Sciences, University of Colorado, Boulder, CO 80303 (United States)

2012-08-10

274

NASA's Living with a Star Program: The Geospace Mission Concept  

NASA Technical Reports Server (NTRS)

NASA has initiated the Living with a Star Program (LWS) to develop the scientific understanding to address the aspects of the Connected Sun-Earth system that affect life and society. A goal of the program is to bridge the gap between science, engineering, and user application communities. This will enable future science, operational, and commercial objectives in space and atmospheric environments by improving engineering approaches to the accommodation and/or mitigation of the effects of solar variability on technological systems. Three program elements are the Science Missions; a Theory, Modeling, and Data Analysis program; and a Space Environment Testbeds program. Because many of the effects of solar variability on humanity are observed in Geospace regions of space, the science research for all three elements of the LWS Program have significant components in Geospace regions.

Barth, Janet L.; Giles, Barbara; Zanetti, Lawrence; Spann, James; Day, John H. (Technical Monitor)

2002-01-01

275

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

Microsoft Academic Search

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

Adriana D. Briscoe; Gary D. Bernard

2005-01-01

276

Molecular evolution of the rhodopsin gene of marine lamprey, Petromyzon marinus  

Microsoft Academic Search

Visual pigment genes have been isolated from a marine lamprey, Petromyzon marinus. We report here the rhodopsin gene, spanning 21.2 kb from start to stop codons, making it the longest opsin gene known in vertebrates. Southern analysis suggests that the lamprey genome contains a single rhodopsin gene. The amino acid (aa) sequence deduced from this gene has 92% sequence similarity

Huan Zhang; Shozo Yokoyama

1997-01-01

277

The Molecular Basis of a Spectral Shift in the Rhodopsins of Two Species of Squid from Different Photic Environments  

Microsoft Academic Search

The molecular basis of spectral tuning of rhodopsin pigments in two squid species is examined. The absorbance spectra of rhodopsin extracts from Alloteuthis subulata (lambda max 499 nm) showed a 5 nm red shift compared with Loligo forbesi (lambda max 494 nm). The rhodopsin gene sequence of A. subulata opsin was determined from polymerase chain reaction (PCR) amplified fragments by

Alex Morris; James K. Bowmaker; David M. Hunt

1993-01-01

278

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

PubMed

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 lambda(max) = 355 nm and 398 nm. Along with the additional UV opsin, Heliconius have also evolved 3-hydroxy-DL-kynurenine (3-OHK)-based yellow wing pigments not found in close relatives. Visual models of how butterflies perceive wing color variation indicate this has resulted in an expansion of the number of distinguishable yellow colors on Heliconius wings. Functional diversification of the UV-sensitive visual pigments may help explain why the yellow wing pigments of Heliconius are so colorful in the UV range compared to the yellow pigments of close relatives lacking the UV opsin duplicate. PMID:20133601

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

2010-02-23

279

Differential Expression of Photoreceptor-Specific Genes in the Retina of a Zebrafish Cadherin2 Mutant glass onion and Zebrafish Cadherin4 Morphants  

PubMed Central

Cadherins are Ca++-dependent transmembrane molecules that mediate cell-cell adhesion through homophilic interactions. Cadherin2 (also called N-cadherin) and cadherin4 (also called R-cadherin), members of the classic cadherin subfamily, have been shown to be involved in development of a variety of tissues and organs including the visual system. To gain insight into cadherin2 and cadherin4 function in differentiation of zebrafish photoreceptors, we have analyzed expression patterns of several photoreceptor-specific genes (crx, gnat1, gnat2, irbp, otx5, rod opsin, rx1, and uv opsin) and/or a cone photoreceptor marker (zpr-1) in the retina of a zebrafish cadherin2 mutant, glass onion (glo) and in zebrafish embryos injected with a cadherin4 specific antisense morpholino oligonucleotide (cdh4MO). We find that expression of all these genes, and of zpr-1, is greatly reduced in the retina of both the glo and cadherin4 morphants. Moreover, in these embryos, expression of some genes (e.g. gnat1, gnat2 and irbp) is more affected than others (e.g.rod opsin and uv opsin). In embryos with both cadherins functions blocked (glo embryos injected with the cdh4MO), the eye initially formed, but became severely and progressively disintegrated and expressed little or no crx and otx5 as development proceeded. Our results suggest that cadherin2 and cadherin4 play important roles in the differentiation of zebrafish retinal photoreceptors.

Liu, Q.; Frey, R. A.; Babb-Clendenon, S. G.; Liu, B.; Francl, J.; Wilson, A. L.; Marrs, J. A.; Stenkamp, D. L.

2007-01-01

280

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

Microsoft Academic Search

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

Christopher M. Hofmann; Kelly E. O'Quin; N. Justin Marshall; Thomas W. Cronin; Ole Seehausen; Karen L. Carleton

2009-01-01

281

Mouse Cone Photoreceptors Co-express Two Functional Visual Arrestins  

PubMed Central

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

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

2008-01-01

282

Visual responses in mice lacking critical components of all known retinal phototransduction cascades.  

PubMed

The mammalian visual system relies upon light detection by outer-retinal rod/cone photoreceptors and melanopsin-expressing retinal ganglion cells. Gnat1(-/-);Cnga3(-/-);Opn4(-/-) mice lack critical elements of each of these photoreceptive mechanisms via targeted disruption of genes encoding rod ? transducin (Gnat1); the cone-specific ?3 cyclic nucleotide gated channel subunit (Cnga3); and melanopsin (Opn4). Although assumed blind, we show here that these mice retain sufficiently widespread retinal photoreception to drive a reproducible flash electroretinogram (ERG). The threshold sensitivity of this ERG is similar to that of cone-based responses, however it is lost under light adapted conditions. Its spectral efficiency is consistent with that of rod opsin, but not cone opsins or melanopsin, indicating that it originates with light absorption by the rod pigment. The TKO light response survives intravitreal injection of U73122 (a phospholipase C antagonist), but is inhibited by a missense mutation of cone ? transducin (Gnat2(cpfl3)), suggesting Gnat2-dependence. Visual responses in TKO mice extend beyond the retina to encompass the lateral margins of the lateral geniculate nucleus and components of the visual cortex. Our data thus suggest that a Gnat1-independent phototransduction mechanism downstream of rod opsin can support relatively widespread responses in the mammalian visual system. This anomalous rod opsin-based vision should be considered in experiments relying upon Gnat1 knockout to silence rod phototransduction. PMID:21124780

Allen, Annette E; Cameron, Morven A; Brown, Timothy M; Vugler, Anthony A; Lucas, Robert J

2010-01-01

283

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

Microsoft Academic Search

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

Alexander Idnurm; Joseph Heitman

2005-01-01

284

A Simplified Mass-Transfer Model for Visual Pigments in Amphibian Retinal-Cone Outer Segments  

PubMed Central

When radiolabeled precursors and autoradiography are used to investigate turnover of protein components in photoreceptive cone outer segments (COSs), the labeled components—primarily visual pigment molecules (opsins)—are diffusely distributed along the COS. To further assess this COS labeling pattern, we derive a simplified mass-transfer model for quantifying the contributions of advective and diffusive mechanisms to the distribution of opsins within COSs of the frog retina. Two opsin-containing regions of the COS are evaluated: the core axial array of disks and the plasmalemma. Numerical solutions of the mass-transfer model indicate three distinct stages of system evolution. In the first stage, plasmalemma diffusion is dominant. In the second stage, the plasmalemma density reaches a metastable state and transfer between the plasmalemma and disk region occurs, which is followed by an increase in density that is qualitatively similar for both regions. The final stage consists of both regions slowly evolving to the steady-state solution. Our results indicate that autoradiographic and cognate approaches for tracking labeled opsins in the COS cannot be effective methodologies for assessing new disk formation at the base of the COS.

Weber, Paul W.; Howle, Laurens E.; Murray, Mark M.; Corless, Joseph M.

2011-01-01

285

The evolution of color vision in nocturnal mammals  

Microsoft Academic Search

Nonfunctional visual genes are usually associated with species that inhabit poor light environments (aquatic\\/subterranean\\/nocturnal), and these genes are believed to have lost function through relaxed selection acting on the visual system. Indeed, the visual system is so adaptive that the reconstruction of intact ancestral opsin genes has been used to reject nocturnality in ancestral primates. To test these assertions, we

Huabin Zhao; Stephen J. Rossiter; Emma C. Teeling; Chanjuan Li; James A. Cotton; Shuyi Zhang

2009-01-01

286

Cysteine Residues 110 and 187 are Essential for the Formation of Correct Structure in Bovine Rhodopsin  

Microsoft Academic Search

To investigate the role of different cysteine residues in bovine rhodopsin, a series of mutants were prepared in which the cysteine residues were systematically replaced by serines. The mutant genes were expressed in monkey kidney cells (COS-1) and the mutant opsins were evaluated for their levels of expression, glycosylation patterns, and ability to form the chromophore characteristic of rhodopsin and

Sadashiva S. Karnik; Thomas P. Sakmar; Hai-Bao Chen; H. Gobind Khorana

1988-01-01

287

Rhodopsin mutants that bind but fail to activate transducin  

Microsoft Academic Search

Rhodopsin is a member of a family of receptors that contain seven transmembrane helices and are coupled to G proteins. The nature of the interactions between rhodopsin mutants and the G protein, transducin (G{sub t}), was investigated by flash photolysis in order to monitor directly G{sub t} binding and dissociation. Three mutant opsins with alterations in their cytoplasmic loops bound

R. R. Franke; T. P. Sakmar; H. G. Khorana; B. Koenig; K. P. Hofmann

1990-01-01

288

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

289

Two-step process for photoreceptor formation in Drosophila  

Microsoft Academic Search

The formation of photoreceptor cells (PRCs) in Drosophila serves as a paradigm for understanding neuronal determination and differentiation. During larval stages, a precise series of sequential inductive processes leads to the recruitment of eight distinct PRCs (R1-R8). But, final photoreceptor differentiation, including rhabdomere morphogenesis and opsin expression, is completed four days later, during pupal development. It is thought that photoreceptor

Bertrand Mollereau; Maria Dominguez; Rebecca Webel; Nansi Jo Colley; Benison Keung; Jose F. de Celis; Claude Desplan

2001-01-01

290

Illumination of the melanopsin signaling pathway.  

PubMed

In mammals, a small population of intrinsically photosensitive retinal ganglion cells (ipRGCs) plays a key role in the regulation of nonvisual photic responses, such as behavioral responses to light, pineal melatonin synthesis, pupillary light reflex, and sleep latency. These ipRGCs also express melanopsin (Opn4), a putative opsin-family photopigment that has been shown to play a role in mediating these nonvisual photic responses. Melanopsin is required for the function of this inner retinal pathway, but its precise role in generating photic responses has not yet been determined. We found that expression of melanopsin in Xenopus oocytes results in light-dependent activation of membrane currents through the Galpha(q)/Galpha(11) G protein pathway, with an action spectrum closely matching that of melanopsin-expressing ipRGCs and of behavioral responses to light in mice lacking rods and cones. When coexpressed with arrestins, melanopsin could use all-trans-retinaldehyde as a chromophore, which suggests that it may function as a bireactive opsin. We also found that melanopsin could activate the cation channel TRPC3, a mammalian homolog of the Drosophila phototransduction channels TRP and TRPL. Melanopsin therefore signals more like an invertebrate opsin than like a classical vertebrate rod-and-cone opsin. PMID:15681390

Panda, Satchidananda; Nayak, Surendra K; Campo, Brice; Walker, John R; Hogenesch, John B; Jegla, Tim

2005-01-28

291

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

292

Molecular evolution of the Rh3 gene in Drosophila  

Microsoft Academic Search

Previous investigations into the evolution of the Drosophila opsin gene family are extended by inter- and intraspecific DNA sequence comparisons of the Rh3 locus in the melanogaster subgroup and D. pseudoobscura. Two separate statistical tests of the neutral-mutation hypothesis suggest that random genetic drift is responsible for virtually all of the observed amino acid replacement substitutions within the melanogaster subgroup.

Francisco José Ayala; Belinda S. W. Chang; Daniel L. Harti

1993-01-01

293

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

294

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

Microsoft Academic Search

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

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

1999-01-01

295

Solar and interplanetary sources of major geomagnetic storms (Dst ? ?100 nT) during 1996–2005  

Microsoft Academic Search

We present the results of an investigation of the sequence of events from the Sun to the Earth that ultimately led to the 88 major geomagnetic storms (defined by minimum Dst ? ?100 nT) that occurred during 1996–2005. The results are achieved through cooperative efforts that originated at the Living with a Star (LWS) Coordinated Data-Analysis Workshop (CDAW) held at

J. Zhang; I. G. Richardson; D. F. Webb; N. Gopalswamy; E. Huttunen; J. C. Kasper; N. V. Nitta; W. Poomvises; B. J. Thompson; C.-C. Wu; S. Yashiro; A. N. Zhukov

2007-01-01

296

A photoionization model of the compact H II region G29.96-0.02  

Microsoft Academic Search

We present a detailed photoionization model of G29.96-0.02 (hereafter G29.96), one of the brightest Galactic Ultra Compact H Ii (UCHII) regions in the Galaxy. This source has been observed extensively at radio and infrared wavelengths. The most recent data include a complete ISO (SWS and LWS) spectrum, which displays a remarkable richness in atomic fine-structure lines. The number of observables

C. Morisset; D. Schaerer; N. L. Martín-Hernández; E. Peeters; F. Damour; J.-P. Baluteau; P. Cox; P. Roelfsema

2002-01-01

297

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

298

Simultaneous observation of ionospheric plasma bubbles and mesospheric gravity waves during the SpreadFEx Campaign  

Microsoft Academic Search

During the Spread F Experiment campaign, under NASA Living with a Star (LWS) program, carried out in the South American Magnetic Equator region from 22 September to 8 November 2005, two airglow CCD imagers, located at Cariri (7.4° S, 36.5° W, geomag. 11° S) and near Brasilia (14.8° S, 47.6° W, geomag. 10° S) were operated simultaneously and measured the

H. Takahashi; M. J. Taylor; P.-D. Pautet; A. F. Medeiros; D. Gobbi; C. M. Wrasse; J. Fechine; M. A. Abdu; I. S. Batista; E. Paula; D. Arruda; S. L. Vadas; F. S. Sabbas; D. C. Fritts

2009-01-01

299

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

NASA Technical Reports Server (NTRS)

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

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

2002-01-01

300

A printed ‘bull-eye’ leaky-wave antenna fed by a non-directive surface-wave launcher  

Microsoft Academic Search

A planar `bull-eye' antenna design that utilizes surface-waves (SWs) for leaky-wave (LW) excitation is investigated for millimeter-wave frequencies of operation. Specifically, a planar non-directive surface-wave launcher (SWL) is employed as the antenna feed, generating bidirectional SW field distributions on a grounded dielectric slab (GDS). By the addition of annular metallic strip gratings, LWs can be excited on the planar guiding

Symon K. Podilchak; Simone Paulotto; Paolo Burghignoli; Yahia M. M. Antar; Paolo Baccarelli; Al P. Freundorfer; Giampiero Lovat

2009-01-01

301

Solar Dynamics Observatory and Solar Sentinels Missions in Living With A Star Program  

NASA Astrophysics Data System (ADS)

We live in the extended atmosphere of an active star. While sunlight enables and sustains life, the Sun's variability produces streams of high-energy particles and radiation that can affect life. In the year 2000 NASA established a new program called the Living With a Star (LWS). The objective of this program is to "develop the scientific understanding necessary to effectively address those aspects of the Connected SunEarth system that directly affect life and society." To address this objective NASA formulated two groups of mission scenarios in the LWS Space Weather Research Network: (a) solar dynamics elements (Solar Dynamics Observatory/Sentinels) that observe the Sun and track disturbances originating there and (b) geospace dynamics elements (Geospace Missions Network) consisting of constellations of small satellites located in key regions around the Earth to measure downstream effects. Science payload for the first mission of LWS, namely Solar Dynamics Observatory (SDO) to study the Sun as a magnetic variable star and quantify its input into the Earth's atmosphere has been selected with a launch date of 2007. Details of the scientific objectives of the mission and its payload will be discussed. Solar Sentinels, a set of notional missions to investigate the physics of interplanetary medium that link solar processes to Earth's environment are planned to be launched in the 2010-2013 time frame depending on budgetary and other factors. A small fleet of spacecraft (four in the nominal plan) will be used to track and understand the evolution of matter ejected from the Sun. Concepts which are presently under study for the future missions will be described in detail. Although originally a U.S. initiative, the problems that LWS addresses are global in nature. Thus under the auspices of IACG an International Living With a Star (ILWS) working group has been established and I will report on the joint activities between NASA and other space agencies.

Guhathakurta, M.

302

Magnetic sensors for automotive applications  

Microsoft Academic Search

Magnetic sensors offer several key advantages: they allow contactless and, consequently, wear-free measurement of mechanical quantities like angle of rotation and angular speed. They are robust and inexpensive to manufacture.As one example of magnetic sensors in production at Robert Bosch GmbH, the steering wheel sensor LWS3 is shown, developed for the electronic stability program (ESP), which prevents vehicles from spinning.

C. P. O Treutler

2001-01-01

303

Learnability of Red-Green Opponency  

NASA Technical Reports Server (NTRS)

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

Ahumada, Albert J., Jr.

1997-01-01

304

Advance Directives in an Oncologic Intensive Care Unit: A Contemporary Analysis of their Frequency, Type, and Impact  

PubMed Central

Abstract Background Our objective was to provide a contemporary analysis of the prevalence, types, and impact of advance health care directives in critically ill cancer patients. Methods We retrospectively reviewed all intensive care unit (ICU) admissions (January 1, 2006 to April 25, 2008) at an oncologic center and identified all patients who completed a living will (LW), or health care proxy (HCP), or neither prior to ICU admission. Demographics, clinical data, end-of-life (EOL) parameters and outcomes were compared among three groups: LWs, HCPs, and no LW or HCP. Results Of 1,333 ICU admissions, 1,121 patients (84%) were included for analysis: 176 patients (15.7%) had LW, 534 (47.6%) had HCP and 411 (36.7%) had no LW or HCP. Patients with LW were significantly more likely to be older and white as compared to patients with HCP alone, or no LW or HCP. There were no significant demographic differences between patients with HCP or no LW or HCP. Patients with HCP alone, or no LW or HCP, were significantly more likely to have Medicaid than patients with LW. There were no differences noted in ICU care, EOL management, or outcomes among the three groups. Conclusions The prevalence of LWs in patients admitted to our oncologic ICU is low. More than half of the remaining patients had designated HCPs. Older age and white race were associated with the presence of LWs. However, the presence of LWs or HCPs did not influence ICU care, EOL management or outcomes at our institution.

Pastores, Stephen M.; Chou, Joanne F.; Chawla, Sanjay; Thaler, Howard T.

2011-01-01

305

Warm molecular gas in the envelope and outflow of IRAS 12496-7650 (DK Chamaeleontis)  

NASA Astrophysics Data System (ADS)

Aims.To obtain insight into the physical structure of the warm gas in the inner envelope of protostars and the interaction with the outflow. Methods: .Sub-millimeter observations of 12CO, 13CO and/or C18O in J=3-2, J=4-3 and J=7-6 were obtained with the APEX Telescope towards IRAS 12496-7650, an intermediate mass young stellar object. The data are compared to ISO-LWS observations of CO J=14-13 up to J=19-18 lines to test the different proposed origins of the CO lines. Results: .The outflow is prominently detected in the 3-2 and 4-3 lines, but not seen at similar velocities in the 7-6 line, constraining the temperature in the high-velocity (>5 km s-1 from line center) gas to less than 50 K, much lower than inferred from the analysis of the ISO-LWS data. In addition, no isothermal gas model can reproduce the emission in both the 7-6 and the higher-J ISO-LWS lines. The 7-6 line probably originates in the inner (<250 AU) region of the envelope at ~150 K. Detailed radiative transfer calculations suggest that the ISO-LWS lines are excited by a different mechanism, possibly related to the larger-scale outflow. All possible mechanisms on scales smaller than 8'' are excluded. High-resolution continuum as well as high-J 12CO and isotopic line mapping are needed to better constrain the structure of the warm gas in the inner envelope and the interaction with the outflow.

van Kempen, T. A.; Hogerheijde, M. R.; van Dishoeck, E. F.; Güsten, R.; Schilke, P.; Nyman, L.-Å.

2006-08-01

306

Physiological Features of the S- and M-cone Photoreceptors of Wild-type Mice from Single-cell Recordings  

PubMed Central

Cone cells constitute only 3% of the photoreceptors of the wild-type (WT) mouse. While mouse rods have been thoroughly investigated with suction pipette recordings of their outer segment membrane currents, to date no recordings from WT cones have been published, likely because of the rarity of cones and the fragility of their outer segments. Recently, we characterized the photoreceptors of Nrl?/? mice, using suction pipette recordings from their “inner segments” (perinuclear region), and found them to be cones. Here we report the use of this same method to record for the first time the responses of single cones of WT mice, and of mice lacking the ?-subunit of the G-protein transducin (Gt??/?), a loss that renders them functionally rodless. Most cones were found to functionally co-express both S- (?max = 360 nm) and M- (?max = 508 nm) cone opsins and to be maximally sensitive at 360 nm (“S-cones”); nonetheless, all cones from the dorsal retina were found to be maximally sensitive at 508 nm (“M-cones”). The dim-flash response kinetics and absolute sensitivity of S- and M-cones were very similar and not dependent on which of the coexpressed cone opsins drove transduction; the time to peak of the dim-flash response was ?70 ms, and ?0.2% of the circulating current was suppressed per photoisomerization. Amplification in WT cones (A ?4 s?2) was found to be about twofold lower than in rods (A ?8 s?2). Mouse M-cones maintained their circulating current at very nearly the dark adapted level even when >90% of their M-opsin was bleached. S-cones were less tolerant to bleached S-opsin than M-cones to bleached M-opsin, but still far more tolerant than mouse rods to bleached rhodopsin, which exhibit persistent suppression of nearly 50% of their circulating current following a 20% bleach. Thus, the three types of mouse opsin appear distinctive in the degree to which their bleached, unregenerated opsins generate “dark light.”

Nikonov, Sergei S.; Kholodenko, Roman; Lem, Janis; Pugh, Edward N.

2006-01-01

307

Spatial variation of the longitudinal dispersion coefficient in an estuary  

NASA Astrophysics Data System (ADS)

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

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

2011-08-01

308

Spatial variation of the longitudinal dispersion coefficient in an estuary  

NASA Astrophysics Data System (ADS)

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

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

2011-12-01

309

Assessing Lévy walks as models of animal foraging.  

PubMed

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. PMID:21632609

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

2011-09-01

310

The distribution of the Intermediate and Deep Water Masses on 60N in the Atlantic Ocean in 2006-2011.  

NASA Astrophysics Data System (ADS)

Subpolar water structure in Atlantic Ocean has been analyzed using the newest hydrochemical data as well as CTD data. Water mass properties are compared to measurement data obtained in 2006, 2009 and 2011. New data analysis made it possible to reveal, that gradual Labrador Sea Water (LWS) dense lower core destruction in Irminger Basin and Icelandic Basin has been going on within the period of 2006-2011. In 2009 and 2011 dual-mode LWS structure was already not observed. New, developed Labrador Sea waters have spread in the upper layer. In addition to that arctic waters' influence increased slightly, and the tendency of intermediate southern-origin waters' intense penetration to the north continued. The detected LWS and Icelandic-Scotlandic Overflow Water (ISOW) warming, salinization and depletion in dissolved oxygen in Irminger Basin and Icelandic Basin have been going on in 2006-2011, happening simultaneously. Such a mode of water mass interaction in years 2000 is a reflection of the fact that one of the meridional circulation pattern dynamic phase is being completed. The mode is establishing, when water exchange between North Atlantic and Arctic Ocean is going to be defined by a weak current in the intermediate layer, intense entrance of deep waters from the north as well as strong subtropical Atlantic water transfer to the north.

Kolokolova, Alexandra

2014-05-01

311

Analysis of Kinesin-2 Function in Photoreceptor Cells Using Synchronous Cre-loxP Knockout of Kif3a with RHO-Cre  

PubMed Central

PURPOSE To determine the relationship between the presence of kinesin-2 and photoreceptor cell viability and opsin transport, by generating RHO-Cre transgenic mice and breeding them to mice with a floxed kinesin-2 motor gene. METHODS Different lines of RHO-Cre transgenic mice were generated and characterized by transgene expression, histology, and electrophysiology. Mice from one line, showing uniform transgene expression, were crossed with Kif3aflox/ Kif3aflox mice. The time courses of photoreceptor Cre expression, KIF3A loss, ectopic opsin accumulation, and photoreceptor cell death were determined by Western blot analysis and microscopy. RESULTS One of the RHO-Cre lines effected synchronous expression of Cre and thus uniform excision of Kif3aflox in rod photoreceptors across the retina. After the neonatal production of CRE and the initiation of KIF3A loss, ectopic accumulation of opsin was detected by postnatal day (P)7, and ensuing photoreceptor cell death was evident after P10 and almost complete by P28. Of importance, the photoreceptor cilium formed normally, and the disc membranes of the nascent outer segment remained normal until P10. CONCLUSIONS The RHO-Cre-8 mice provide an improved tool for studying gene ablation in rod photoreceptor cells. Regarding kinesin-2 function in photoreceptor cells, the relatively precise timing of events after CRE excision of Kif3aflox allows us to conclude that ectopic opsin is a primary cellular lesion of KIF3A loss, consistent with the hypothesis that opsin is a cargo of kinesin-2. Moreover, it demonstrates that KIF3A loss results in very rapid photoreceptor cell degeneration.

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

2007-01-01

312

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

313

Diversity and functional properties of bistable pigments.  

PubMed

Rhodopsin and related opsin-based pigments, which are photosensitive membrane proteins, have been extensively studied using a wide variety of techniques, with rhodopsin being the most understood G protein-coupled receptor (GPCR). Animals use various opsin-based pigments for vision and a wide variety of non-visual functions. Many functionally varied pigments are roughly divided into two kinds, based on their photoreaction: bistable and monostable pigments. Bistable pigments are thermally stable before and after photo-activation, but monostable pigments are stable only before activation. Here, we review the diversity of bistable pigments and their molecular characteristics. We also discuss the mechanisms underlying different molecular characteristics of bistable and monostable pigments. In addition, the potential of bistable pigments as a GPCR model is proposed. PMID:20852774

Tsukamoto, Hisao; Terakita, Akihisa

2010-11-01

314

Cone-based vision in the aging mouse  

PubMed Central

People often experience age-related declines in cone-based visual capacities despite an absence of apparent visual pathology. Although mice are used as models of human visual pathologies associated with aging, little is known about how age impacts vision in animals with disease-free retinas since most studies have heretofore examined relatively young mice. We examined the effects of age on cone-based vision by assessing opsin gene transcription, cone densities, the flicker electroretinogram (ERG), and behavioral increment thresholds in mice. ERG measurements of cone function showed age-related declines in maximum voltage (Vmax), while opsin gene transcription, cone density, and increment thresholds were unchanged even in extremely old mice. The age-related decline in Vmax seen in mice is qualitatively similar to that documented for human subjects. It is notable that Vmax, a commonly used index of ERG activity, does not predict behavioral performance in the mouse.

Williams, Gary A.; Jacobs, Gerald H.

2007-01-01

315

A comprehensive multiscale framework for simulating optogenetics in the heart  

PubMed Central

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

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

2013-01-01

316

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

PubMed

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. PMID:22628477

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

2012-09-01

317

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

318

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

319

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

320

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

2011-08-01

321

A molecular phylogeny and the evolution of nest architecture and behavior in Trigona s.s. (Hymenoptera: Apidae: Meliponini)  

Microsoft Academic Search

Stingless bees exhibit extraordinary variation in nest architecture within and among species. To test for phylogenetic association\\u000a of behavioral traits for species of the Neotropical stingless bee genus Trigona s.s., a phylogenetic hypothesis was generated by combining sequence data of 24 taxa from one mitochondrial (16S rRNA) and four\\u000a nuclear gene fragments (long-wavelength rhodopsin copy 1 (opsin), elongation factor-1? copy

Claus Rasmussen; João M. F. Camargo

2008-01-01

322

Self-Organized Criticality: A Guide to Water-Protein Landscape Evolution  

Microsoft Academic Search

We focus here on red cone opsin transmembrane proteins, using a hydropathic elastic roughening tool previously applied to the rhodopsin rod transmembrane proteins. This tool is based on a non-Euclidean metric realistically rooted in the atomic coordinates of 5526 protein segments, which thereby encapsulates universal non-Euclidean long-range differential geometrical features of globular proteins in the Protein Data Bank. Whereas the

J. C. Phillips

2011-01-01

323

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

324

Light and darkness regulate melanopsin in the retinal ganglion cells of the albino wistar rat  

Microsoft Academic Search

Circadian rhythms are daily adjusted to the environmental day\\/night cycle by photic input via the retinohypothalamic tract\\u000a (RHT). Recent studies indicate that melanopsin, a newly identified opsin-like molecule, is involved in the light responsiveness\\u000a of retinal ganglion cells (RGCs) constituting the RHT. In the present study, we examined the expression of melanopsin at the\\u000a mRNA and protein level during a

Jens Hannibal; Birgitte Georg; Peter Hindersson; Jan Fahrenkrug

2005-01-01

325

Cloning and expression of a Xenopus short wavelength cone pigment.  

PubMed

The short wavelength visual pigment from Xenopus responsible for vision in the blue/violet portion of the spectrum was characterized by sequence spectroscopic analysis. The amino acid sequence was deduced by sequencing clones isolated by reverse transcription PCR, from retinal cDNA and genomic libraries. The gene contains 5 exons spanning 8.4 kb of genomic DNA and produces an mRNA of 2.4 kb in length. The deduced amino acid sequence predicts a protein of 347 amino acids with 76-78% identity to other short wavelength opsins. The mRNA encoding the Xenopus violet pigment was detected using in situ hybridization in cones, comprising a few percent of the total photoreceptors in the adult retina. The Xenopus violet opsin cDNA, modified to contain an epitope from the carboxyl terminus of bovine rhodopsin, was expressed in COS1 cells by transient transfection and analysed by UV-visible absorption spectroscopy. The protein expressed in COS1 cells migrated at 34 kD and was glycosylated at a single site in the amino terminus, exhibiting a diffuse pattern on SDS PAGE similar to bovine rhodopsin expressed in COS1 cells. Following incubation with 11-cis retinal, a light-sensitive pigment was formed with the lambdamax=425+/-2 nm. A Schiff base linkage between retinal and the violet opsin was demonstrated by acid denaturation. Xenopus violet opsin was sensitive to hydroxylamine in the dark, reacting with a half-time of 5 min at room temperature. This is the first group S pigment for amphibians. The pigment was expressed and purified from COS1 cells in a form that has permitted for the first time determination of the extinction coefficient, reactivity to hydroxylamine and presence of a Schiff base. PMID:9733587

Starace, D M; Knox, B E

1998-08-01

326

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

327

Common Transcriptional Mechanisms for Visual Photoreceptor Cell Differentiation among Pancrustaceans  

PubMed Central

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

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

2014-01-01

328

Common Transcriptional Mechanisms for Visual Photoreceptor Cell Differentiation among Pancrustaceans.  

PubMed

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

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

2014-07-01

329

A view to kill.  

PubMed

Genome and proteome data from Hydra magnipapillata have opened the way for the molecular analysis of an ancient nervous system, which includes stinging cells, an unusual neurosensory and neurosecretory cell type. They hold some surprises for the mechanisms and evolution of sensory transduction that could not have been anticipated from what has been learned from flies and vertebrates. Research in BMC Biology now implicates the ancient opsin-mediated transduction pathway in the neuronal control of stinging cell discharge. PMID:22390773

Holstein, Thomas W

2012-01-01

330

Different Selective Pressures Shape the Molecular Evolution of Color Vision in Chimpanzee and Human Populations  

Microsoft Academic Search

A population genetic analysis of the long-wavelength opsin (OPN1LW, ''red'') color vision gene in a global sample of 236 human nucleotide sequences had previously discovered nine amino acid replacement single nucleotide polymorphisms, which were found at high frequencies in both African and non-African populations and associated with an unusual haplotype diversity. Although this pattern of nucleotide diversity is consistent with

Brian C. Verrelli; Cecil M. Lewis Jr; Anne C. Stone; George H. Perry

2008-01-01

331

Molecular ecology and adaptation of visual photopigments in craniates.  

PubMed

In craniates, opsin-based photopigments expressed in the eye encode molecular 'light sensors' that constitute the initial protein in photoreception and the activation of the phototransduction cascade. Since the cloning and sequencing of the first vertebrate opsin gene (bovine rod opsin) nearly 30?years ago (Ovchinnikov Yu 1982, FEBS Letters, 148, 179-191; Hargrave et al. 1983, Biophysics of Structure & Mechanism, 9, 235-244; Nathans & Hogness 1983, Cell, 34, 807-814), it is now well established that variation in the subtypes and spectral properties of the visual pigments that mediate colour and dim-light vision is a prevalent mechanism for the molecular adaptation to diverse light environments. In this review, we discuss the origins and spectral tuning of photopigments that first arose in the agnathans to sample light within the ancient aquatic landscape of the Early Cambrian, detailing the molecular changes that subsequently occurred in each of the opsin classes independently within the main branches of extant jawed gnathostomes. Specifically, we discuss the adaptive changes that have occurred in the photoreceptors of craniates as they met the ecological challenges to survive in quite differing photic niches, including brightly lit aquatic surroundings; the deep sea; the transition to and from land; diurnal, crepuscular and nocturnal environments; and light-restricted fossorial settings. The review ends with a discussion of the limitations inherent to the 'nocturnal-bottleneck' hypothesis relevant to the evolution of the mammalian visual system and a proposition that transition through a 'mesopic-bottleneck' may be a more appropriate model. PMID:22650357

Davies, Wayne I L; Collin, Shaun P; Hunt, David M

2012-07-01

332

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

333

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

Microsoft Academic Search

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

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

2006-01-01

334

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

335

The Role of Interphotoreceptor Retinoid-Binding Protein on the Translocation of Visual Retinoids and Function of Cone Photoreceptors  

PubMed Central

The first event in light perception is absorption of a photon by the retinaldehyde chromophore of an opsin pigment in a rod or cone photoreceptor cell. This induces isomerization of the chromophore, rendering the bleached pigment insensitive to light. Restoration of light sensitivity requires chemical reisomerization of retinaldehyde via a multistep enzyme pathway, called the visual cycle, in cells of the retinal pigment epithelium (RPE). Interphotoreceptor retinoid-binding protein (IRBP) is present in the extracellular space between photoreceptors and the RPE. IRBP is known to bind visual retinoids. Previous studies on irbp?/? mice suggested that IRBP plays an insignificant role in opsin-pigment regeneration. However, the mice in these studies were uncontrolled for a severe mutation in the rpe65 gene. Rpe65 catalyzes the rate-limiting step in the visual cycle. Here, we examined the phenotype in irbp?/? mice homozygous for the wild-type (Leu450) rpe65 gene. We show that lack of IRBP causes delayed transfer of newly synthesized chromophore from RPE to photoreceptors. Removal of bleached chromophore from photoreceptors is also delayed in irbp?/? retinas after light exposure. It was previously shown that rods degenerate in irbp?/? mice. Here,weshow that cones and rods degenerate at similar rates. However, cones are more affected functionally and show greater reductions in outer segment length than rods in irbp?/? mice. The disproportionate reductions in cone function and outer-segment length appear to result from mistrafficking of cone opsins due to impaired delivery of retinaldehyde chromophore, which functions as a chaperone for cone opsins but not rhodopsin.

Jin, Minghao; Li, Songhua; Nusinowitz, Steven; Lloyd, Marcia; Hu, Jane; Radu, Roxana A.; Bok, Dean; Travis, Gabriel H.

2009-01-01

336

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

337

Multiple mechanisms of rhabdom shedding in the lateral eye of Limulus polyphemus.  

PubMed

Rhabdom shedding in horseshoe crab lateral eye photoreceptors was studied with anti-opsin and anti-arrestin immunocytochemistry. Two, possibly three, distinct shedding mechanisms were revealed in animals maintained in natural lighting. Transient rhabdom shedding, triggered by dawn, is a brief, synchronous event that removes up to 10% of the rhabdom membrane. Whorls of rhabdomeral membrane break into vesicles and form compact multivesicular bodies. These debris particles are immunoreactive for opsin and are of a relatively uniform size, averaging approximately 2 microm(2) in area. Transient shedding requires that input from circadian efferent fibers to the retina precedes the light trigger, and cutting the optic nerve blocks efferent input and transient shedding. Light-driven rhabdom shedding is a progressive process. Rhabdomeral membrane is removed by coated vesicles that accumulate into loosely packed multivesicular bodies. These debris particles label with antibodies directed against opsin, arrestin, and adaptin, and they have a large distribution of sizes, averaging almost 6 microm(2) in area and ranging up to 25 microm(2) or more. The amount of rhabdomeral membrane removed by light-driven shedding has seasonal variation and depends on latitude. Light-driven shedding does not require circadian efferent input. A possible third shedding mechanism, light-independent shedding, is observed when transient shedding is blocked either by 48 hours of darkness or by cutting the optic nerve. Small particles, averaging 1.8 microm(2) in area, exhibiting opsin but not arrestin immunoreactivity can then be found in the cytoplasm surrounding the rhabdom. The nature of light-independent shedding is not yet clear. PMID:12115691

Sacunas, Robert B; Papuga, M Owen; Malone, Michael A; Pearson, Anthony C; Marjanovic, Milos; Stroope, Darrell G; Weiner, William W; Chamberlain, Steven C; Battelle, Barbara-Anne

2002-07-15

338

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

NASA Astrophysics Data System (ADS)

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

Phillips, J. C.

2013-02-01

339

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

340

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. These cells are intrinsically photosensitive, but also receive inputs from rod and cone photoreceptors, acting as the primary sensory conduit mediating non-image-forming responses to light. Multiple subtypes of pRGC have been described in the mouse retina with characteristic morphologies and functional properties, and which perform distinct physiological roles. 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, 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

2013-09-01

341

Photosensitivities of rhodopsin mutants with a displaced counterion.  

PubMed

Visual pigments consist of a protein moiety opsin and an 11-cis-retinal chromophore that is covalently bound to the opsin via a Schiff base linkage. They have a high photosensitivity, which can be attributed to the high probability of photon absorption and the high photoisomerization quantum yield of the retinal chromophore. Both of these parameters are regulated by the opsin, though the precise mechanism is unknown. We previously found that counterion residue E113, which stabilizes the proton on the Schiff base, is involved in the efficient photoisomerization in vertebrate visual pigments. To test the positional effect of the counterion on the photon absorption and the photoisomerization, we measured the photosensitivities of a set of mutants of bovine rhodopsin in which the counterion was displaced to position 90, 94, 117, or 292. The molar extinction coefficient was reduced in many of the mutants, leading to reductions in the photosensitivity for monochromatic lights. However, the oscillator strength, the probability of photon absorption integrated over the entire wavenumber range of the absorption band, was relatively similar among the mutants and the wild type. In addition, the quantum yields of the mutants were not markedly different from that of the wild type. These results indicate that the counterion does not need to be located at position 113 for a high photosensitivity for natural light. Interestingly, all of the mutants exhibited greatly increased hydroxylamine sensitivity. This result suggests that the counterion in vertebrate visual pigments is optimally located for the stability of the Schiff base linkage. PMID:21038858

Tsutsui, Kei; Shichida, Yoshinori

2010-11-30

342

The molecular basis for UV vision in birds: spectral characteristics, cDNA sequence and retinal localization of the UV-sensitive visual pigment of the budgerigar (Melopsittacus undulatus).  

PubMed Central

Microspectrophotometric (msp) studies have shown that the colour-vision system of many bird species is based on four pigments with absorption peaks in the red, green, blue and UV regions of the spectrum. The existence of a fourth pigment (UV) is the major difference between the trichromacy of humans and the tetrachromacy of such birds, and recent studies have shown that it may play a determining role in such diverse aspects of behaviour as mate selection and detection of food. Avian visual pigments are composed of an opsin protein covalently bound via a Schiff-base linkage to the chromophore 11-cis-retinal. Here we report the cDNA sequence of a UV opsin isolated from an avian species, Melopsittacus undulatus (budgerigar or small parakeet). This sequence has been expressed using the recombinant baculovirus system; the pigment generated from the expressed protein on addition of 11-cis-retinal yielded an absorption spectrum typical of a UV photopigment, with lambdamax 365+/-3 nm. This is the first UV opsin from an avian species to be sequenced and expressed in a heterologous system. In situ hybridization of this sequence to budgerigar retinas selectively labelled a sub-set of UV cones, representing approx. 9% of the total cone population, that are distributed in a semi-regular pattern across the entire retina.

Wilkie, S E; Vissers, P M; Das, D; Degrip, W J; Bowmaker, J K; Hunt, D M

1998-01-01

343

Diversity of Color Vision: Not All Australian Marsupials Are Trichromatic  

PubMed Central

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

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

2010-01-01

344

Nontuberculous mycobacteria in women, young and old.  

PubMed

Lady Windermere syndrome is a unique entity within the spectrum of pulmonary NTM diseases. There are differences in several clinical aspects between Lady Windermere syndrome and the classic pulmonary NTM disease, including manifestations, pathogenesis, and natural history. Recently, emerging pieces of information provide a more scientific explanation of why women are more susceptible to this form of infection and how they develop clinical disease. As the result, these patients probably require quite different diagnostic and therapeutic approaches compared with those with the classic presentation. Studies exclusive to LWS are lacking and are absolutely necessary as they will enhance our understanding of, and hence successful management strategies for, this increasingly recognized disease. PMID:12371003

Chalermskulrat, Worakij; Gilbey, Jack G; Donohue, James F

2002-09-01

345

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

Microsoft Academic Search

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

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

2000-01-01

346

High Angular Resolution Mid-Infrared Imaging of Young Stars in Orion BN/KL  

NASA Technical Reports Server (NTRS)

The authors present Keck LWS images of the Orion BN/KL star forming region obtained in the first multi-wavelength study to have 0.3--0.5 resolution from 4.7 (micro)m to 22 (micro)m. The young stellar objects designed infrared source n and radio source I are believed to dominate the BN/KL region. They have detected extended emission from a probable accretion disk around source n but infer a stellar luminosity on the order of only 2000 L(sub (center-dot)).

Greenhill, L. J.; Gezari, D. Y.; Danchi, W. C.; Najita, J.; Monnier, J. D.

2004-01-01

347

Instrumentation for optical remote sensing from space; Proceedings of the Meeting, Cannes, France, November 27-29, 1985  

NASA Technical Reports Server (NTRS)

Papers are presented on such topics as the development of the Imaging Spectrometer for Shuttle and space platform applications; the in-flight calibration of pushbroom remote sensing instruments for the SPOT program; buttable detector arrays for 1.55-1.7 micron imaging; the design of the Improved Stratospheric and Mesospheric Sounder on the Upper Atmosphere Research Satellite; and SAGE II design and in-orbit performance. Consideration is also given to the Shuttle Imaging Radar-B/C instruments; the Venus Radar Mapper multimode radar system design; various ISO instruments (ISOCAM, ISOPHOT, and SWS and LWS); and instrumentation for the Space Infrared Telescope Facility.

Seeley, John S. (editor); Lear, John W. (editor); Russak, Sidney L. (editor); Monfils, Andre (editor)

1986-01-01

348

Spitzer observations of supernova remnants: II. Physical conditions and comparison with HH7 and HH54  

Microsoft Academic Search

We have studied the shock-excited molecular regions associated with four\\u000asupernova remnants (SNRs) - IC443C, W28, W44 and 3C391 - and two Herbig-Haro\\u000aobjects, HH7 and HH54, using Spitzer's Infrared Spectrograph (IRS). The\\u000aphysical conditions within the observed areas are inferred from spectroscopic\\u000adata obtained from IRS and from SWS and LWS onboard ISO, together with\\u000aphotometric data from Spitzer's

Yuan Yuan; David A. Neufeld

2010-01-01

349

The Living With a Star Space Environment Testbed Experiments  

NASA Technical Reports Server (NTRS)

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

Xapsos, Michael A.

2014-01-01

350

The Second NWRA Flare-Forecasting Comparison Workshop: Preliminary Results  

NASA Astrophysics Data System (ADS)

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

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

2013-07-01

351

Diffuse emissions in Carina nebula (Mizutani+, 2004)  

NASA Astrophysics Data System (ADS)

table2.dat shows the line intensities obtained by ISO/LWS and SWS for the central 40'x20' area of the Carina nebula, cantered at (l,b)=(287.4, -0.6) with a 3" grid. It contains the intensities of [OI]63micron, [OI]145micron, [CII]158micron, [SiII]35micron, and H2 0-0 S(3) 9.66micron lines, as well as the total far-infrared intensity and the radiation field strength (Go). (1 data file).

Mizutani, M.; Onaka, T.; Shibai, H.

2004-08-01

352

Mid and far-infrared spectra of the third brightest carbon star IRAS 15194-5115  

NASA Astrophysics Data System (ADS)

ISO observations from 2 to 197 microns of the recently discovered, third brightest (at 12 microns) carbon star IRAS 15194-5115, are analysed. Eighty spectra, covering the entire range from 2.3 microns to 45 microns, were observed in the ISO medium-high resolution mode (SWS06). Also, observations were made with the ISO long wavelength spectrometer (LWS) from 42 to 197 microns. The evolutionary stage and chemistry are discussed and a comparison to the similar carbon star IRC+10216 is made.

Ryde, N.; Eriksson, K.; Gustafsson, B.; Jorgensen, U. G.; Nyman, L.-Aa.; Olofsson, H.; Plez, B.; Wolstencroft, R.

353

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

NASA Astrophysics Data System (ADS)

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

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

354

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

NASA Astrophysics Data System (ADS)

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

Stepinski, Tadeusz; Ambrozinski, Lukasz; Uhl, Tadeusz

2013-04-01

355

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

356

Unique photoreceptor arrangements in a fish with polarized light discrimination.  

PubMed

In contrast to other vertebrates, some anchovies have cone photoreceptors with longitudinally oriented outer segment lamellae. These photoreceptors are axially dichroic (i.e., they are sensitive to the polarization of axially incident light) and form the basis of a polarization detection system in the northern anchovy, Engraulis mordax. Whether other cone types exist in the retina of this animal, and whether multiple cone opsins are expressed in the retinas of anchovies, is unknown. Likewise, a detailed examination of photoreceptor ultrastructure in nondichroic photoreceptors has not been carried out despite its importance to understand visual specializations within the retina and its use in the formulation of models to explain cellular structure. Here, I combined light and electron microscopy with immunohistochemical studies of opsin expression to infer mechanisms of lamellar formation and to evaluate the potential for color vision in the northern anchovy retina. Morphological observations revealed three cone formations: 1) continuous rows made up of alternating long and short (bilobed) cones with longitudinally oriented lamellae that are orthogonal between cone types; 2) continuous rows of alternating long and short cones in which only the short cones have longitudinally oriented lamellae; and 3) rows of triple cones with transversely oriented lamellae, each triple cone consisting of two lateral cones flanking a small central cone. Ultrastructure investigations supported two models of outer segment formation resulting in the longitudinally oriented lamellae of long and short cones. In the case of the long cone, lateral compression of the outer segment, potentially via the formation of guanine platelet stacks in neighboring pigment epithelium cells, results in a shape transformation from conical to cunate and a tilt from transverse to longitudinal lamellae. In the case of the short (bilobed) cone, membrane invaginations from the connecting ciliary structure grow longitudinally to form a dichroic stack. Opsin expression studies indicated that all cones express middle-to-long wavelength opsins, with long and lateral cones possessing a different opsin from that in short and central cones, confirming the potential for color vision. Together with the ultrastructural observations, these results suggest that the unique cone topography in the northern anchovy retina may underlie a visual system with segregated color and polarization detection channels. PMID:21246551

Novales Flamarique, Iñigo

2011-03-01

357

The Objectives of NASA's Living with a Star Space Environment Testbed  

NASA Technical Reports Server (NTRS)

NASA is planning to fly a series of Space Environment Testbeds (SET) as part of the Living With A Star (LWS) Program. The goal of the testbeds is to improve and develop capabilities to mitigate and/or accommodate the affects of solar variability in spacecraft and avionics design and operation. This will be accomplished by performing technology validation in space to enable routine operations, characterize technology performance in space, and improve and develop models, guidelines and databases. The anticipated result of the LWS/SET program is improved spacecraft performance, design, and operation for survival of the radiation, spacecraft charging, meteoroid, orbital debris and thermosphere/ionosphere environments. The program calls for a series of NASA Research Announcements (NRAs) to be issued to solicit flight validation experiments, improvement in environment effects models and guidelines, and collateral environment measurements. The selected flight experiments may fly on the SET experiment carriers and flights of opportunity on other commercial and technology missions. This paper presents the status of the project so far, including a description of the types of experiments that are intended to fly on SET-1 and a description of the SET-1 carrier parameters.

Barth, Janet L.; LaBel, Kenneth A.; Brewer, Dana; Kauffman, Billy; Howard, Regan; Griffin, Geoff; Day, John H. (Technical Monitor)

2001-01-01

358

Restoration of AMPTE/CHEM Data  

NASA Astrophysics Data System (ADS)

The highest time resolution digital data for the Charge-Energy-Mass (CHEM) Spectrometer instrument on the Active Magnetospheric Particle Explorers (AMPTE) mission has been restored and made available online at http://sd-www.jhuapl.edu/AMPTE. During the period 1984 to the beginning of 1989, CHEM measured the mass and charge-state compositions as well as the energy spectra and pitch-angle distributions of all major ions from H through Fe with energies from 0.3 to 300 keV/charge. The data cadence is less than one minute. With the spacecraft in a low inclination orbit passing through the magnetopause and well into the magnetosphere, many samplings of the ring-current were made. The data itself consist of so-called PHA (pulse height analysis) events, in which the energy per charge, time of flight, and total energy are measured for each particle. The original Fortran software for calculating fluxes from the PHA events has been ported from VMS to modern Unix Fortran compilers. The CHEM data will be very useful in conjunction with the upcoming Radiation Belt Storm Probe (RBSP) mission, which is part of NASA's Living With a Star (LWS) initiative, and this restoration effort was funded through the LWS Targeted Research and Technology (TR&T) program.

Vandegriff, J.

2006-12-01

359

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

360

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.

361

The Role of Surface Friction in Downslope Windstorms  

Microsoft Academic Search

Numerical simulations of the 11 January 1972 windstorm in Boulder, Colorado, were carded out using a hydrostatic model with a turbulent kinetic energy parameterization to investigate the role of fictional effects in the development of nonlinear mountain waves. Sensitivity tests to the roughness length specification and to the turbulent mixing and dissipation length formulations show that surface friction delays the

Evelyne Richard; Patrick Mascart; Everett C. Nickerson

1989-01-01

362

Thermal lensing in recycling interferometric gravitational wave detectors  

Microsoft Academic Search

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

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

1994-01-01

363

Radome health monitoring with Lamb waves: experimental approach  

Microsoft Academic Search

With intent to ensure health monitoring of foam core sandwich structures by a system based on ultrasonic methods, the use of Lamb waves is investigated. The propagation mechanisms are analyzed and reveal leaky waves properties. Moreover, the wave sensitivity to damages induced by low-velocity impacts is tested and the feasibility to detect debonding and foam failure is evaluated.

N Bourasseau; E Moulin; C Delebarre; P Bonniau

2000-01-01

364

Ciliary photoreceptors in the cerebral eyes of a protostome larva  

PubMed Central

Background Eyes in bilaterian metazoans have been described as being composed of either ciliary or rhabdomeric photoreceptors. Phylogenetic distribution, as well as distinct morphologies and characteristic deployment of different photopigments (ciliary vs. rhabdomeric opsins) and transduction pathways argue for the co-existence of both of these two photoreceptor types in the last common bilaterian ancestor. Both receptor types exist throughout the Bilateria, but only vertebrates are thought to use ciliary photoreceptors for directional light detection in cerebral eyes, while all other invertebrate bilaterians studied utilize rhabdomeric photoreceptors for this purpose. In protostomes, ciliary photoreceptors that express c-opsin have been described only from a non-visual deep-brain photoreceptor. Their homology with vertebrate rods and cones of the human eye has been hypothesized to represent a unique functional transition from non-visual to visual roles in the vertebrate lineage. Results To test the hypothesis that protostome cerebral eyes employ exclusively rhabdomeric photoreceptors, we investigated the ultrastructure of the larval eyes in the brachiopod Terebratalia transversa. We show that these pigment-cup eyes consist of a lens cell and a shading pigment cell, both of which are putative photoreceptors, deploying a modified, enlarged cilium for light perception, and have axonal connections to the larval brain. Our investigation of the gene expression patterns of c-opsin, Pax6 and otx in these eyes confirms that the larval eye spots of brachiopods are cerebral eyes that deploy ciliary type photoreceptors for directional light detection. Interestingly, c-opsin is also expressed during early embryogenesis in all potential apical neural cells, becoming restricted to the anterior neuroectoderm, before expression is initiated in the photoreceptor cells of the eyes. Coincident with the expression of c-opsin in the presumptive neuroectoderm, we found that middle gastrula stage embryos display a positive photoresponse behavior, in the absence of a discrete shading pigment or axonal connections between cells. Conclusions Our results indicate that the dichotomy in the deployment of ciliary and rhabdomeric photoreceptors for directional light detection is not as clear-cut as previously thought. Analyses of brachiopod larval eyes demonstrate that the utilization of c-opsin expressing ciliary photoreceptors in cerebral eyes is not limited to vertebrates. The presence of ciliary photoreceptor-based eyes in protostomes suggests that the transition between non-visual and visual functions of photoreceptors has been more evolutionarily labile than previously recognized, and that co-option of ciliary and rhabdomeric photoreceptor cell types for directional light detection has occurred multiple times during animal evolution. In addition, positive photoresponse behavior in gastrula stage embryos suggests that a discrete shading pigment is not requisite for directional photoreception in metazoans. Scanning photoreception of light intensities mediating cell-autonomous changes of ciliary movement may represent an ancient mechanism for regulating locomotory behavior, and is likely to have existed prior to the evolution of eye-mediated directional light detection employing axonal connections to effector cells and a discreet shading pigment.

2011-01-01

365

Light Prevents Exogenous 11-cis Retinal from Maintaining Cone Photoreceptors in Chromophore-Deficient Mice  

PubMed Central

Purpose. To determine the effect of light/dark cycles on the cones of 11-cis retinal–treated RPE65/rhodopsin double knockout (Rpe65?/?Rho?/?) mice. Studies have shown that cones degenerate in chromophore-deficient mouse models for Leber Congenital Amaurosis (LCA), but exogenous supplementation of the native 11-cis retinal chromophore can inhibit this degeneration, suggesting that 11-cis retinal could be used as a therapeutic agent for preserving functional cones in patients with LCA. However, these treated mice were maintained in the dark. Methods. 11-cis Retinal was introduced into Rpe65?/?Rho?/? mice at postnatal day 10 as a single subcutaneous injection mixed with a basement membrane matrix. The mice were maintained in either normal light/dark cycles or constant dark conditions. Fluorescence microscopy was used to assess retinal morphology. Cone cell survival was determined by counting cone opsin–containing cells on flat-mounted P30 retinas. Cross-sections of P21 mouse retina were used to assess cone cell integrity by visualizing opsin localization. Cone function was determined by electroretinography (ERG). Results. Previous studies have shown that 11-cis retinal–treated mice lacking RPE65 and raised in constant dark have higher cone photoreceptor cell number, improved cone opsin localization, and enhanced cone ERG signals when compared with untreated mice. However, in this study the authors show that 11-cis retinal–treated Rpe65?/?Rho?/? mice raised in cyclic light did not show the improvements seen with the dark-reared mice. Conclusions. Thus, 11-cis retinal by itself, as well as other agents that form photosensitive pigments, will not be good therapeutic candidates for preserving cones in LCA.

Fan, Jie; Crouch, Rosalie K.

2011-01-01

366

Proof of oligomeric state of frog rhodopsin: visualization of dimer and oligomers on gels after BN- and HRCN-PAGE using antibodies to rhodopsin and by retinylopsin fluorescence.  

PubMed

Staining by antibodies to rhodopsin (Rh) and fluorescence of N-retinylopsin (RO) have shown that digitonin (DIG)- , dodecyl-?-D-maltoside (DM)- , and sodium dodecyl sulfate (SDS)-solubilized frog Rh after BN- and HRCN-PAGE is situated in the gradient gel in the state of dimer with a slight content of higher oligomers (trimer, tetramer, etc.). With increasing detergent harshness (DIG < DM < SDS), the proportion of higher oligomers in extracts becomes more prominent. Formation of RO in rod outer segments (ROS) in the presence of 0.7 M NaBH(3)CN at pH 5.0 occurs only when Rh is simultaneously photolyzed during reduction. Dithiothreitol at the concentration of 0.005 M failed to induce RO production. Formation of a stable C-N bond between all-trans-retinal and opsin in RO is accompanied by decrease in the dimer share and increase in the share of the higher oligomers due to secondary dissociation-aggregation of solubilized opsin. The position of the Rh dimer in relation to the anode during both native electrophoreses is determined not only by its molecular mass, but probably also depends on unfolding degree (or form): the harsher the detergent, the closer to the anode the dimer is located. Treatment of ROS by agents modifying the cholesterol component of lipid membrane (M?CD, filipin III, nystatin, saponin) did not change the character of Rh oligomerization, thus showing that integrity of the cholesterol component of photoreceptor membrane is not a crucial factor for oligomerization of opsin. It is supposed that the dimer-oligomer "portrait" of frog Rh, which has been found by two methods of native electrophoresis in three detergents with different degree of harshness, corresponds to a physiological state of this protein in native photoreceptor membrane. PMID:21073427

Shukolyukov, S A

2010-08-01

367

Structure and function in rhodopsin: correct folding and misfolding in point mutants at and in proximity to the site of the retinitis pigmentosa mutation Leu-125-->Arg in the transmembrane helix C.  

PubMed

L125R is a mutation in the transmembrane helix C of rhodopsin that is associated with autosomal dominant retinitis pigmentosa. To probe the orientation of the helix and its packing in the transmembrane domain, we have prepared and studied the mutations E122R, I123R, A124R, S127R, L125F, and L125A at, and in proximity to, the above mutation site. Like L125R, the opsin expressed in COS-1 cells from E122R did not bind 11-cis-retinal, whereas those from I123R and S127R formed the rhodopsin chromophore partially. A124R opsin formed the rhodopsin chromophore (lambda max 495 nm) in the dark, but the metarhodopsin II formed on illumination decayed about 6.5 times faster than that of the wild type and was defective in transducin activation. The mutant opsins from L125F and L125A bound 11-cis-retinal only partially, and in both cases, the mixtures of the proteins produced were separated into retinal-binding and non-retinal-binding (misfolded) fractions. The purified mutant rhodopsin from L125F showed lambda max at 500 nm, whereas that from L125A showed lambda max at 503 nm. The mutant rhodopsin L125F showed abnormal bleaching behavior and both mutants on illumination showed destabilized metarhodopsin II species and reduced transducin activation. Because previous results have indicated that misfolding in rhodopsin is due to the formation of a disulfide bond other than the normal disulfide bond between Cys-110 and Cys-187 in the intradiscal domain, we conclude from the misfolding in mutants L125F and L125A that the folding in vivo in the transmembrane domain is coupled to that in the intradiscal domain. PMID:8643443

Garriga, P; Liu, X; Khorana, H G

1996-05-14

368

Structure and function in rhodopsin: correct folding and misfolding in point mutants at and in proximity to the site of the retinitis pigmentosa mutation Leu-125-->Arg in the transmembrane helix C.  

PubMed Central

L125R is a mutation in the transmembrane helix C of rhodopsin that is associated with autosomal dominant retinitis pigmentosa. To probe the orientation of the helix and its packing in the transmembrane domain, we have prepared and studied the mutations E122R, I123R, A124R, S127R, L125F, and L125A at, and in proximity to, the above mutation site. Like L125R, the opsin expressed in COS-1 cells from E122R did not bind 11-cis-retinal, whereas those from I123R and S127R formed the rhodopsin chromophore partially. A124R opsin formed the rhodopsin chromophore (lambda max 495 nm) in the dark, but the metarhodopsin II formed on illumination decayed about 6.5 times faster than that of the wild type and was defective in transducin activation. The mutant opsins from L125F and L125A bound 11-cis-retinal only partially, and in both cases, the mixtures of the proteins produced were separated into retinal-binding and non-retinal-binding (misfolded) fractions. The purified mutant rhodopsin from L125F showed lambda max at 500 nm, whereas that from L125A showed lambda max at 503 nm. The mutant rhodopsin L125F showed abnormal bleaching behavior and both mutants on illumination showed destabilized metarhodopsin II species and reduced transducin activation. Because previous results have indicated that misfolding in rhodopsin is due to the formation of a disulfide bond other than the normal disulfide bond between Cys-110 and Cys-187 in the intradiscal domain, we conclude from the misfolding in mutants L125F and L125A that the folding in vivo in the transmembrane domain is coupled to that in the intradiscal domain. Images Fig. 2

Garriga, P; Liu, X; Khorana, H G

1996-01-01

369

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

370

Limited variation in visual sensitivity among bowerbird species suggests that there is no link between spectral tuning and variation in display colouration.  

PubMed

Variation in visual spectral tuning has evolved in concert with signal colour in some taxa, but there is limited evidence of this pattern in birds. To further investigate this possibility, we compared spectral sensitivity among bowerbird species that occupy different visual habitats and are highly diverged in plumage and decoration colour displays, which are important in mate choice and possibly reproductive isolation. Microspectrophotometry of violet-, short-, medium- and long-wavelength-sensitive cones revealed no significant interspecific variation in visual pigment peak spectral absorbance values that ranged between 404-410, 454, 503-511 and 558-568 nm, respectively. Mean cut-off wavelength values for C-, Y-, R- and P-type coloured oil droplets were 418-441, 508-523, 558-573 and 412-503 nm, respectively, with values at longer wavelengths in ventral compared with dorsal retina cones. Low ocular media mid-wavelength transmission values (340-352 nm) suggest that bowerbirds may represent a transitional stage in the evolution from the ancestral violet-sensitive- to the derived ultraviolet-sensitive-type short-wavelength-sensitive-1-based visual system found in younger passerine lineages. Sequence data obtained for rod opsin and four cone opsin genes were identical at key tuning sites, except for an interspecific leucine-52-alanine polymorphism in the short-wavelength-sensitive 2 opsin. There was no obvious relationship between relative proportions of cone classes and either visual habitat or display colour. Overall, we detected little interspecific variation in bowerbird spectral sensitivity and no association between sensitivity and display diversity, which is consistent with the general trend among avian taxa. PMID:22399654

Coyle, Brian J; Hart, Nathan S; Carleton, Karen L; Borgia, Gerald

2012-04-01

371

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

2013-01-01

372

The maturation of photoreceptors in the avian retina Is stimulated by thyroid hormone  

PubMed Central

During retinal development, the cell-fate of photoreceptors is committed long before maturation, which entails the expression of opsins and functional transduction of light. The mechanisms that delay the maturation of photoreceptors remain unknown. We have recently reported that immature photoreceptors express the LIM domain transcription factors Islet2 and Lim3, as well as the cell-surface glycoprotein axonin1 (Fischer et al., 2008a). As the photoreceptors mature to form outer segments and express photopigments, the expression of the Islet2, Lim3 and axonin1 is diminished. The purpose of this study was to investigate whether Thyroid Hormone (TH) influences the maturation of photoreceptors. We studied the maturation of photoreceptors across the gradient of maturity that exists in far peripheral regions of the postnatal chicken retina (Ghai et al., 2008). We found that intraocular injections of TH down-regulated Islet2, Lim3 and axonin1 in photoreceptors in far peripheral regions of the retina. By contrast, TH stimulated the up-regulation of red-green opsin, violet opsin, rhodopsin and calbindin in photoreceptors. We found a correlation between the onset of RLIM (RING finger LIM-domain binding protein) and down-regulation of Islet2 and Lim3 in maturing photoreceptors; RLIM is known to interfere with the transcriptional activity of LIM-domain transcription factors. We conclude that TH stimulates the maturation of photoreceptors in the avian retina. We propose that TH inhibits the expression of Islet2 and Lim3, which thereby permits photoreceptor maturation and the onset of photopigment-expression.

Fischer, Andy J.; Bongini, Rachel; Bastaki, Nasma; Sherwood, Patrick

2011-01-01

373

Quantum mechanical/molecular mechanical structure, enantioselectivity, and spectroscopy of hydroxyretinals and insights into the evolution of color vision in small white butterflies.  

PubMed

Since Vogt's discovery of A(3)-retinal or 3-hydroxyretinal in insects in 1983 and Matsui's discovery of A(4)-retinal or 4-hydroxyretinal in firefly squid in 1988, hydroxyretinal-protein interactions mediating vision have remained largely unexplored. In the present study, A(3)- and A(4)-retinals are theoretically incorporated into squid and bovine visual pigments by use of the hybrid quantum mechanics/molecular mechanics [SORCI+Q//B3LYP/6-31G(d):Amber96] method, and insights into structure, enantioselectivity, and spectroscopy are gathered and presented for the first time. Contrary to general perception, our findings rule out the formation of a hydrogen bond between the hydroxyl-bearing ?-ionone ring portion of retinal and opsin. Compared to A(1)-pigments, A(3)- and A(4)-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 scintillans) opsin is very similar to that of the Japanese common squid (Todarodes pacificus) opsin; (ii) the molecular mechanism of spectral tuning in small white butterflies involve sites S116 and T185 and breaking of a hydrogen bond between sites E180 and T185; and finally (iii) A(3)-retinal may have occurred during the conversion of A(1)- to A(2)-retinal and insects may have acquired them, in order to absorb light in the blue-green wavelength region and to speed up the G-protein signaling cascade. PMID:22087641

Sekharan, Sivakumar; Yokoyama, Shozo; Morokuma, Keiji

2011-12-29

374

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

PubMed Central

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

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

2013-01-01

375

Origins and antiquity of X-linked triallelic color vision systems in New World monkeys  

PubMed Central

It is known that the squirrel monkey, marmoset, and other related New World (NW) monkeys possess three high-frequency alleles at the single X-linked photopigment locus, and that the spectral sensitivity peaks of these alleles are within those delimited by the human red and green pigment genes. The three alleles in the squirrel monkey and marmoset have been sequenced previously. In this study, the three alleles were found and sequenced in the saki monkey, capuchin, and tamarin. Although the capuchin and tamarin belong to the same family as the squirrel monkey and marmoset, the saki monkey belongs to a different family and is one of the species that is most divergent from the squirrel monkey and marmoset, suggesting the presence of the triallelic system in many NW monkeys. The nucleotide sequences of these alleles from the five species studied indicate that gene conversion occurs frequently and has partially or completely homogenized intronic and exonic regions of the alleles in each species, making it appear that a triallelic system arose independently in each of the five species studied. Nevertheless, a detailed analysis suggests that the triallelic system arose only once in the NW monkey lineage, from a middle wavelength (green) opsin gene, and that the amino acid differences at functionally critical sites among alleles have been maintained by natural selection in NW monkeys for >20 million years. Moreover, the two X-linked opsin genes of howler monkeys (a NW monkey genus) were evidently derived from the incorporation of a middle (green) and a long wavelength (red) allele into one chromosome; these two genes together with the (autosomal) blue opsin gene would immediately enable even a male monkey to have trichromatic vision.

Boissinot, Stephane; Tan, Ying; Shyue, Song-Kun; Schneider, Horacio; Sampaio, Iracilda; Neiswanger, Katherine; Hewett-Emmett, David; Li, Wen-Hsiung

1998-01-01

376

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

377

Transmembrane Helix-helix Association: Relative Stabilities at Low pH†  

PubMed Central

We have previously studied the unfolding equilibrium of bacterio-opsin in a single phase solvent, using Förster mechanism fluorescence resonance energy transfer (FRET) as a probe, from tryptophan donors to a dansyl acceptor. We observed an apparent unfolding transition in bacterio-opsin perturbed by increasing ethanol concentrations [Nannepaga et al.(2004) Biochemistry 43, 50–59]. We have further investigated this transition and find the unfolding is pH-dependent. We have now measured the apparent pK of acid-induced unfolding of bacterio-opsin in 90% ethanol. When the acceptor is on helix B (Lys 41), the apparent pK for unfolding is 4.75; on the EF connecting loop (Cys 163), 5.15; and on helix G (Cys 222), 5.75. Five-helix proteolytic fragments are less stable. The apparent unfolding pKs are, for residues 72-248 (Cys 163), 5.46; and 1-166 (Lys 41), 7.36. When interpreted in terms of a simple equilibrium model for unfolding, the apparent pKs give relative free energies of unfolding, in the range of ?0.54 to ?3.5 kcal/mol. The results suggest that the C-terminal helix of bacterio-opsin is less stably folded than the N-terminal helices. We analyzed the pair-wise helix-helix interaction surfaces of bacteriorhodopsin and three other 7-transmembrane helix proteins, based on crystal structures. The results show that the interaction surfaces are smoother and the helix axis separations are closer in the amino-terminal two-thirds of the proteins compared with the carboxyl terminal one-third. However, the F helix is important in stabilizing the folded structure, as shown by the instability of the 1-166 fragment. Considering the high resolution crystal structure of bacteriorhodopsin, there are no obvious helix-helix interactions involving protein side chains which would be destabilized by protonation at the estimated pH of the unfolding transitions. However, a number of helix-bridging water molecules could become protonated, thereby weakening the helix-helix interactions.

Valluru, Neelima; Silva, Frances; Dhage, Manmath; Rodriguez, Gustavo; Alloor, Srinivas R.; Renthal, Robert

2008-01-01

378

A view to kill  

PubMed Central

Genome and proteome data from Hydra magnipapillata have opened the way for the molecular analysis of an ancient nervous system, which includes stinging cells, an unusual neurosensory and neurosecretory cell type. They hold some surprises for the mechanisms and evolution of sensory transduction that could not have been anticipated from what has been learned from flies and vertebrates. Research in BMC Biology now implicates the ancient opsin-mediated transduction pathway in the neuronal control of stinging cell discharge. See research article http://www.biomedcentral.com/1741-7007/10/17

2012-01-01

379

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

380

Seeing the light: a photonic visual prosthesis for the blind  

NASA Astrophysics Data System (ADS)

This paper highlights how the genetic incorporation of artificial opsins into the retina can lead to a new class of retinal prosthesis. We demonstrate the efficacy of incorporating channelrhodopsin into neuron cells in-vitro and show how that can be scaled to in-vivo. We show that we need typically 100mW/cm2 of instantaneous light intensity on the neuron in order to stimulate action potentials which results in 10W/cm2 required from the light source. We thus use GaN LED arrays to provide spatially controlled stimulation which is of sufficient brightness to stimulate the cells.

Degenaar, Patrick; Grossman, Nir; McGovern, Brian; Neil, Mark; Drakakis, Emmanuel; Nikolic, Konstantin

2009-02-01

381

Chlorophyll derivatives as visual pigments for super vision in the red.  

PubMed

The primary event in vision is light-initiated activation of visual pigments. All visual pigments consist of the protein opsin bound to 11-cis-retinal and are responsible for initiating the transformation of light into an electrical signal. In a mouse model, we show that derivatives of chlorophyll can act as visual pigments initiating the transformation of light into an electrical signal and thus change the primary event in vision to initial activation of a chlorophyll derivative. Electroretinographic b-wave amplitudes recorded in response to red and blue light were two-fold greater in mice administered chlorin e(6), which accumulated in photoreceptor outer segments. PMID:17609771

Washington, Ilyas; Zhou, Jilin; Jockusch, Steffen; Turro, Nicholas J; Nakanishi, Koji; Sparrow, Janet R

2007-07-01

382

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

383

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

NASA Astrophysics Data System (ADS)

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× 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.; DuBois, D. F.; Russell, D. A.; Myatt, J. F.

2012-10-01

384

Action Spectra of Zebrafish Cone Photoreceptors  

PubMed Central

Zebrafish is becoming an increasingly popular model in the field of visual neuroscience. Although the absorption spectra of its cone photopigments have been described, the cone action spectra were still unknown. In this study we report the action spectra of the four types of zebrafish cone photoreceptors, determined by measuring voltage responses upon light stimulation using whole cell patch clamp recordings. A generic template of photopigment absorption spectra was fit to the resulting action spectra in order to establish the maximum absorption wavelength, the A2-based photopigment contribution and the size of the ?-wave of each cone-type. Although in general there is close correspondence between zebrafish cone action- and absorbance spectra, our data suggest that in the case of MWS- and LWS-cones there is appreciable contribution of A2-based photopigments and that the ?-wave for these cones is smaller than expected based on the absorption spectra.

Endeman, Duco; Klaassen, Lauw J.; Kamermans, Maarten

2013-01-01

385

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

NASA Technical Reports Server (NTRS)

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

1974-01-01

386

The Solar Dynamics Observatory and Its Contributions to Space Weather  

NASA Technical Reports Server (NTRS)

The Solar Dynamics Observatory (SDO) was launched on 11 February 2010 and has worked flawlessly in its first year and a half of operation. SDO was the first mission launched for NASA's Living With a Star Program (LWS), so its focus is not only studying the causes and drivers of the variable Sun, but also how these variations force similar changes in the Earth and other objects within the Heliosphere. Due to SDO's many Space Weather goals, this presentation will not only show some of the recent, ground-breaking new results provided by SDO, but also focus on the real-time Space Weather advances provided by this spacecraft. A main theme throughout this talk will be methods and tools that researchers around the world can utilize to access and manipulate the SDO data real-time for both fundamental science and Space Weather monitoring purposes.

Chamberlin, Phillip C.

2011-01-01

387

Asteroids as Calibration Standards in the Thermal Infrared -- Applications and Results from ISO  

NASA Astrophysics Data System (ADS)

Asteroids have been used extensively as calibration sources for ISO. We summarise the asteroid observational parameters in the thermal infrared and explain the important modelling aspects. Ten selected asteroids were extensively used for the absolute photometric calibration of ISOPHOT in the far-IR. Additionally, the point-like and bright asteroids turned out to be of great interest for many technical tests and calibration aspects. They have been used for testing the calibration for SWS and LWS, the validation of relative spectral response functions of different bands, for colour correction and filter leak tests. Currently, there is a strong emphasis on ISO cross-calibration, where the asteroids contribute in many fields. Well known asteroids have also been seen serendipitously in the CAM Parallel Mode and the PHT Serendipity Mode, allowing for validation and improvement of the photometric calibration of these special observing modes.

Müller, T. G.; Lagerros, J. S. V.

388

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

NASA Technical Reports Server (NTRS)

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

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

1991-01-01

389

Progress Towards the Solar Dynamics Observatory  

NASA Technical Reports Server (NTRS)

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

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

2002-01-01

390

Mass Flows in a Prominence Spine as Observed in EUV  

NASA Astrophysics Data System (ADS)

We analyze a quiescent prominence observed by the Solar Dynamics Observatory's Atmospheric Imaging Assembly with a focus on mass and energy flows in the spine measured using Lyman continuum absorption. This is the first time this sort of analysis has been applied with an emphasis on individual features and flows in a quiescent prominence. The prominence, observed on 2010 Sept. 28, is detectable in most AIA wavebands in absorption and/or emission. Flows along the spine exhibit horizontal bands 5-10 arcsec wide and kinetic energy fluxes consistent with quiet sun coronal heating estimates. For a discrete moving feature we estimate a mass of a few times 10^11 g. We discuss the implications of our derived properties for models of prominence dynamics, in particular the thermal non-equilibrium model. This project was supported by NASA's LWS TR&T program.

Kucera, Therese A.; Gilbert, Holly; Karpen, Judith T.

2014-06-01

391

Chemical kinetic analysis of thermal decay of rhodopsin reveals unusual energetics of thermal isomerization and hydrolysis of Schiff base.  

PubMed

The thermal properties of rhodopsin, which set the threshold of our vision, have long been investigated, but the chemical kinetics of the thermal decay of rhodopsin has not been revealed in detail. To understand thermal decay quantitatively, we propose a kinetic model consisting of two pathways: 1) thermal isomerization of 11-cis-retinal followed by hydrolysis of Schiff base (SB) and 2) hydrolysis of SB in dark state rhodopsin followed by opsin-catalyzed isomerization of free 11-cis-retinal. We solve the kinetic model mathematically and use it to analyze kinetic data from four experiments that we designed to assay thermal decay, isomerization, hydrolysis of SB using dark state rhodopsin, and hydrolysis of SB using photoactivated rhodopsin. We apply the model to WT rhodopsin and E181Q and S186A mutants at 55 °C, as well as WT rhodopsin in H(2)O and D(2)O at 59 °C. The results show that the hydrogen-bonding network strongly restrains thermal isomerization but is less important in opsin and activated rhodopsin. Furthermore, the ability to obtain individual rate constants allows comparison of thermal processes under various conditions. Our kinetic model and experiments reveal two unusual energetic properties: the steep temperature dependence of the rates of thermal isomerization and SB hydrolysis in the dark state and a strong deuterium isotope effect on dark state SB hydrolysis. These findings can be applied to study pathogenic rhodopsin mutants and other visual pigments. PMID:21921035

Liu, Jian; Liu, Monica Yun; Fu, Li; Zhu, Gefei Alex; Yan, Elsa C Y

2011-11-01

392

A novel rhodopsin-like gene expressed in zebrafish retina.  

PubMed

The visual pigment rhodopsin (rh1) constitutes the first step in the sensory transduction cascade in the rod photoreceptors of the vertebrate eye, forming the basis of vision at low light levels. In most vertebrates, rhodopsin is a single-copy gene whose function in rod photoreceptors is highly conserved. We found evidence for a second rhodopsin-like gene (rh1-2) in the zebrafish genome. This novel gene was not the product of a zebrafish-specific gene duplication event and contains a number of unique amino acid substitutions. Despite these differences, expression of rh1-2 in vitro yielded a protein that not only bound chromophore, producing an absorption spectrum in the visible range (?max ? 500 nm), but also activated in response to light. Unlike rh1, rh1-2 is not expressed during the first 4 days of embryonic development; it is expressed in the retina of adult fish but not the brain or muscle. Similar rh1-2 sequences were found in two other Danio species, as well as a more distantly related cyprinid, Epalzeorhynchos bicolor. While sequences were only identified in cyprinid fish, phylogenetic analyses suggest an older origin for this gene family. Our study suggests that rh1-2 is a functional opsin gene that is expressed in the retina later in development. The discovery of a new previously uncharacterized opsin gene in zebrafish retina is surprising given its status as a model system for studies of vertebrate vision and visual development. PMID:21447259

Morrow, James M; Lazic, Savo; Chang, Belinda S W

2011-07-01

393

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

394

Functional and evolutionary relationships between bacteriorhodopsin and halorhodopsin in the archaebacterium, halobacterium halobium  

NASA Technical Reports Server (NTRS)

The archaebacteria occupy a unique place in phylogenetic trees constructed from analyses of sequences from key informational macromolecules, and their study continues to yield interesting ideas on the early evolution and divergence of biological forms. It is now known that the halobacteria among these species contain various retinal-proteins, resembling eukaryotic rhodopsins, but with different functions. Two of these pigments, located in the cytoplasmic membranes of the bacteria, are bacteriorhodopsin (a light-driven proton pump) and halorhodopsin (a light-driven chloride pump). Comparison of these systems is expected to reveal structure/function relationships in these simple (primitive?) energy transducing membrane components and evolutionary relationships which had produced the structural features which allow the divergent functions. Findings indicate that very different primary structures are needed for these proteins to accomplish their different functions. Indeed, analysis of partial amino acid sequences from halo-opsin shows already that few if any long segments exist which are homologous to bacterio-opsin. Either these proteins diverged a very long time ago to allow for the observed differences, or the evolutionary clock in the halobacteria runs faster than usual.

Lanyi, J. K.

1986-01-01

395

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

396

Archaebacterial rhodopsin sequences: Implications for evolution  

NASA Technical Reports Server (NTRS)

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

Lanyi, J. K.

1991-01-01

397

An optogenetic toolbox designed for primates  

PubMed Central

Optogenetics is a technique for controlling subpopulations of neurons in the intact brain using light. This technique has the potential to enhance basic systems neuroscience research and to inform the mechanisms and treatment of brain injury and disease. Before launching large-scale primate studies, the method needs to be further characterized and adapted for use in the primate brain. We assessed the safety and efficiency of two viral vector systems (lentivirus and adeno-associated virus), two human promoters (human synapsin (hSyn) and human thymocyte-1 (hThy-1)) and three excitatory and inhibitory mammalian codon-optimized opsins (channelrhodopsin-2, enhanced Natronomonas pharaonis halorhodopsin and the step-function opsin), which we characterized electrophysiologically, histologically and behaviorally in rhesus monkeys (Macaca mulatta). We also introduced a new device for measuring in vivo fluorescence over time, allowing minimally invasive assessment of construct expression in the intact brain. We present a set of optogenetic tools designed for optogenetic experiments in the non-human primate brain.

Diester, Ilka; Kaufman, Matthew T; Mogri, Murtaza; Pashaie, Ramin; Goo, Werapong; Yizhar, Ofer; Ramakrishnan, Charu; Deisseroth, Karl; Shenoy, Krishna V

2011-01-01

398

Determination of chromophore structure and environment in bovine visual pigments with resonance Raman spectroscopy  

SciTech Connect

Resonance Raman spectra of /sup 2/H- and /sup 13/C-labeled visual pigments have been obtained and analyzed. The C-C stretching vibrations of rhodopsin, isorhodopsin, and bathorhodopsin have been assigned, as well as those of the 11-cis and 9-cis retinal protonated Schiff base model compounds. The insensitivity of the C/sub 14/-C/sub 15/ stretch frequency to N-deuteration in all three pigments demonstrates that each contains a trans C=N bond. Comparison of the fingerprint modes of the visual pigments and their model compounds shows that the C/sub 10/-C/sub 11/ and C/sub 14/-C/sub 15/ single bonds are s-trans in all three pigments. This provides evidence against the model of bathorhodopsin proposed by Lui and Asato, which suggests a C/sub 10/-C/sub 11/ s-cis structure. The extreme similarity of the C-C stretch modes of rhodopsin and the 11-cis retinal protonated Schiff base argues against the presence of a negatively charged protein residue near C/sub 13/, proposed to be responsible for the opsin shift of rhodopsin. However, the unusually large shift of the C=N stretch frequency upon N-deuteration in rhodopsin relative to the model compound suggests that the opsin shift mechanism may involve altered Schiff base - counter ion interactions.

Palings, H.A.

1987-01-01

399

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

400

Damage of photoreceptor-derived cells in culture induced by light emitting diode-derived blue light  

PubMed Central

Our eyes are increasingly exposed to light from the emitting diode (LED) light of video display terminals (VDT) which contain much blue light. VDTs are equipped with televisions, personal computers, and smart phones. The present study aims to clarify the mechanism underlying blue LED light-induced photoreceptor cell damage. Murine cone photoreceptor-derived cells (661?W) were exposed to blue, white, or green LED light (0.38?mW/cm2). In the present study, blue LED light increased reactive oxygen species (ROS) production, altered the protein expression level, induced the aggregation of short-wavelength opsins (S-opsin), resulting in severe cell damage. While, blue LED light damaged the primary retinal cells and the damage was photoreceptor specific. N-Acetylcysteine (NAC), an antioxidant, protected against the cellular damage induced by blue LED light. Overall, the LED light induced cell damage was wavelength-, but not energy-dependent and may cause more severe retinal photoreceptor cell damage than the other LED light.

Kuse, Yoshiki; Ogawa, Kenjiro; Tsuruma, Kazuhiro; Shimazawa, Masamitsu; Hara, Hideaki

2014-01-01

401

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

402

Range of retinal diseases potentially treatable by AAV-vectored gene therapy.  

PubMed

Viable strategies for retinal gene therapy must be designed to cope with the genetic nature of the disease and/or the primary pathologic process responsible for retinal malfunction. For dominant gene defects the aim must be to destroy the presumably toxic gene product, for recessive gene defects the direct approach aims to provide a wild-type copy of the gene to the affected retinal cell type, and for diseases of either complex or unknown genetic origin, more general cell survival strategies that deal with preserving affected retinal cells are often the best and only option. Hence examples of each type of therapy will be briefly discussed in several animal models, including ribozyme therapy for autosomal dominant retinitis pigmentosa in the transgenic P23H opsin rat, beta-PDE gene augmentation therapy for autosomal recessive retinitis pigmentosa in the rd mouse, glial cell-derived neurotrophic factor (GDNF) gene therapy for autosomal dominant RP in the transgenic S334ter opsin rat and pigment epithelial cell-derived neurotrophic factor (PEDF) gene therapy for neovascular retinal disease in rodents. Each employs a recombinant AAV vectored passenger gene controlled by one of several promoters supporting either photoreceptor-specific expression or more general retinal cell expression depending on the therapeutic requirements. PMID:14750604

Hauswirth, William W; Li, Quihong; Raisler, Brian; Timmers, Adrian M; Berns, Kenneth I; Flannery, John G; LaVail, Matthew M; Lewin, Alfred S

2004-01-01

403

Ribozyme gene therapy for autosomal dominant retinal disease.  

PubMed

Gene delivery to cells of the retina, particularly to photoreceptor cells, has broad potential both for answering basic questions of retinal biology and for more applied therapeutic purposes. The use of ribozymes as therapy for autosomal dominant retinal diseases is a promising technique, and the theoretical and practical basis for their use is discussed. The process involves designing and testing ribozymes first in vitro and then in animal models of retinal disease. Viral vectors based on the nonpathogenic human adeno-associated virus, when coupled with the strong, rod photoreceptor specific opsin promoter, offer an efficient and nontoxic way to deliver and express ribozymes in photoreceptor cells for long time periods of time. Effective ribozyme-mediated therapy also demands careful in vitro analysis of a ribozyme's ability to efficiently and specifically distinguish between mutant and wild type RNAs. Finally, effective demonstration of therapy in an animal model requires careful analysis of any rescue effect in the retina using multiple criteria, including biochemical, structural and physiological assays. For this purpose, ribozyme therapy in a transgenic rat model of retinitis pigmentosa containing a dominant rod opsin mutation (proline-to-histidine change at position 23) is discussed in detail. PMID:10834402

Hauswirth, W W; LaVail, M M; Flannery, J G; Lewin, A S

2000-02-01

404

Diverse types of ganglion cell photoreceptors in the mammalian retina.  

PubMed

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

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

2012-07-01

405

Photoreceptors and photopigments in a subterranean rodent, the pocket gopher (Thomomys bottae).  

PubMed

Pocket gophers (Thomomys bottae) are rodents that spend much of their lives in near-lightless subterranean burrows. The visual adaptations associated with this extreme environment were investigated by making anatomical observations of retinal organization and by recording retinal responses to photic stimulation. The size of the eye is within the normal range for rodents, the lens transmits light well down into the ultraviolet, and the retina conforms to the normal mammalian plan. Electroretinogram recording revealed the presence of three types of photopigments, a rod pigment with a spectral peak of about 495 nm and two types of cone pigment with respective peak values of about 367 nm (UV) and 505 nm (medium-wavelength sensitive). Both in terms of responsivity to lights varying in temporal frequency and in response recovery following intense light adaptation, the cone responses of the pocket gopher are similar to those of other rodents. Labeling experiments indicate an abundance of cones that reach densities in excess of 30,000 mm-2. Cones containing UV opsin are found throughout the retina, but those containing medium-wavelength sensitive opsin are mostly restricted to the dorsal retina where coexpression of the two photopigments is apparently the rule. Rod densities are lower than those typical for nocturnal mammals. PMID:15711968

Williams, Gary A; Calderone, Jack B; Jacobs, Gerald H

2005-02-01

406

Why are blue visual pigments blue? A resonance Raman microprobe study.  

PubMed Central

A resonance Raman microscope has been developed to study the structure of the retinal prosthetic group in the visual pigments of individual photoreceptor cells. Raman vibrational spectra are obtained by focusing the probe laser on intact photoreceptors frozen on a 77 K cold stage. To elucidate the mechanism of wavelength regulation in blue visual pigments, we have used this apparatus to study the structure of the chromophore in the 440-nm absorbing pigment found in "green rods" of the toad (Bufo marinus). The 9-cis isorhodopsin form of the green rod pigment exhibits a 1662-cm-1 C = NH+ Schiff base stretching mode that shifts to 1636 cm-1 in deuterium-substituted H2O. This demonstrates that the Schiff base linkage to the protein is protonated. Protonation of the Schiff base is sufficient to explain the 440-nm absorption maximum of this pigment without invoking any additional protein-chromophore interactions. The absence of additional perturbations is supported by the observation that the ethylenic band and the perturbation-sensitive C-10-C-11 and C-14-C-15 stretching modes have the same frequency as those of the 9-cis protonated retinal Schiff base in solution. Our demonstration that a blue visual pigment contains an unperturbed protonated Schiff base provides experimental evidence that the protein charge perturbation responsible for the opsin shift in the 500-nm absorbing pigments is removed in the opsins of blue pigments, as suggested by the sequence data.

Loppnow, G R; Barry, B A; Mathies, R A

1989-01-01

407

Retinal pigment epithelium protein of 65 kDA gene-linked retinal degeneration is not modulated by chicken acidic leucine-rich epidermal growth factor-like domain containing brain protein/Neuroglycan C/ chondroitin sulfate proteoglycan 5  

PubMed Central

Purpose To analyze in vivo the function of chicken acidic leucine-rich epidermal growth factor-like domain containing brain protein/Neuroglycan C (gene symbol: Cspg5) during retinal degeneration in the Rpe65?/? mouse model of Leber congenital amaurosis. Methods We resorted to mice with targeted deletions in the Cspg5 and retinal pigment epithelium protein of 65 kDa (Rpe65) genes (Cspg5?/?/Rpe65?/?). Cone degeneration was assessed with cone-specific peanut agglutinin staining. Transcriptional expression of rhodopsin (Rho), S-opsin (Opn1sw), M-opsin (Opn1mw), rod transducin ? subunit (Gnat1), and cone transducin ? subunit (Gnat2) genes was assessed with quantitative PCR from 2 weeks to 12 months. The retinal pigment epithelium (RPE) was analyzed at P14 with immunodetection of the retinol-binding protein membrane receptor Stra6. Results No differences in the progression of retinal degeneration were observed between the Rpe65?/? and Cspg5?/?/Rpe65?/? mice. No retinal phenotype was detected in the late postnatal and adult Cspg5?/? mice, when compared to the wild-type mice. Conclusions Despite the previously reported upregulation of Cspg5 during retinal degeneration in Rpe65?/? mice, no protective effect or any involvement of Cspg5 in disease progression was identified.

Cottet, Sandra; Juttner, Rene; Voirol, Nathalie; Chambon, Pierre; Rathjen, Fritz G.; Schorderet, Daniel F.

2013-01-01

408

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; Schu