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Showing 1 to 20 of 50 for “"opsin"”.
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Visual Opsin Diversity in Anurans
… techniques, sequences were obtained for four opsins—the protein component of visual pigments—expressed in anuran retinas. Amino acid sequences of the genes RH1, LWS, SWS1, and SWS2 were compared across taxa to identify variable sites, as such variation can shift the spectral sensitivity of …
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Crustacean phylogenetic systematics and opsin evolution
… bound to an integral membrane protein (opsin), visual pigments are phenotypically characterized by the wavelength of maximal absorption (λmax). The underlying molecular mechanism controlling λmax is the interaction between the opsin amino acid sequence and the chromophore. While a …
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The Effect of Gonadotropin Releasing Hormone on Opsin Gene Expression and Spectral Sensitivity in Zebra Cichlid Fish (Metriaclima zebra).
… has been partially attributed to differences in opsin gene expression, with each species preferentially expressing a subset of seven possible genes. Hormones such as gonadotropin releasing hormone (GnRH) can mediate changes in gene expression and the presence of GnRH immunoreactive fibers and …
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Cichlids as a model for the evolution of visual sensitivity
… this relationship. In Chapter 1, I compare the opsin gene sequences from 17 African cichlid species that have evolved in either clear or turbid light environments. I identify statistical evidence of molecular adaptation. I also find evidence of differences in the relative rates of substitution …
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Extraction of chemical structures and reactions from the literature
… of communicating chemical structure information. OPSIN (Open Parser for Systematic IUPAC Nomenclature), an open source, freely available algorithm for converting chemical names to structures was developed. OPSIN employs a regular grammar to direct tokenisation and parsing leading to the generation …
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Evolution of colour vision in relation to colouration in weaverbirds (Family Ploceidae) and poison dart frogs (Family Dendrobatidae)
… key visual and vision-related genes, including opsin genes, was compared between sexes and seasons in the southern red bishop (Euplectes orix) and cape bishop (Euplectes capensis) using qRT-PCR. Sequences for the same four opsin and two vision-related genes were compared across a dataset of 70 …
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The maintenance of variation in Cyprinodontiformes
… goodei. I measured the diurnal pattern of cone opsin gene expression in the bluefin killifish to see if overall or proportional opsin expression was tuned to match the daily blue-shift in light at dawn and dusk. LWS, RH2-1, RH2-2, and SWS2B (but not SWS1 or SWS2A) opsin gene expression was …
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Rhodopsins as light-detectors: Of visual pigments and human beings
Rhodopsin is the light-sensitive pigment of the photoreceptor cells of higher organisms. Photon absorption by rhodopsin initiates a biochemical amplification cascade that results in an electrical signal. Rhodopsin is composed of the protein opsin, and the chromophore retinal, linked to it by a …
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Strategies for optogenetic stimulation of deep tissue peripheral nerves
… light-sensitive transmembrane protein, called an opsin, such that illumination of the target tissue initiates depolarization; in the case of a neuron, illumination results in the firing of an action potential that can control downstream physiology. The excitement surrounding optogenetics has also …
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Development of Novel Chemical Biology Tools for Probing Structure-Function Relationships in G Protein-Coupled Receptors
… mammalian culture. Using the visual pigment rhodopsin (Rho) as a model GPCR, the strain-promoted [3+2] azide-alkyne cycloaddition reaction (SpAAC) between dibenzocyclooctyne (DIBO) and p-azido-L-phenylalanine (azF) was shown to be a suitable strategy for attaching labels to GPCRs. While …
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Comparative analysis of gene expression in two sexually dimorphic crustacean species Euphilomedes carcharodonta and Euphilomedes morini
… in absentia, Chaoptic, Protein Kinase C and Opsin show different expression patterns between groups. The highest expression levels of Sine oculis are in developing embryos when compared to other stages of development. Dachshund, Seven in absentia, Chaoptic, Protein Kinase C and Opsin show …
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Fourier transform infrared difference spectroscopy of bacteriorhodopsin
… the photocycle and proton pump of bacteriorhodopsin (bR). By applying this method to the study of native bR and bR with modified chromophores, we have confirmed and extended the earlier resonance Raman results concerning the configuration of the chromophore of bR and its intermediates. These …
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Comparing Differentiated Rod And Cone Transcriptomes Reveals Rax As A Controller Of A Defined Cone Gene Regulatory Program
… (rods) or mCherry-only (cones) expressing Rhodopsin (RHO), Neural retina leucin zipper (NRL), Guanine Nucleotide Binding Protein Alpha Transducine 1 (GNAT1) (rod markers) and Short wavelength cone opsin (S-opsin), Medium wavelength cone opsin (M-opsin), Guanine Nucleotide Binding Protein Alpha …
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Molecular Evolution of Visual System Genes in Fishes
… of evolutionary studies on two gene families, opsins and crystallins. Opsin proteins determine the wavelengths of light detected by the retina, while crystallin proteins contribute to lens transparency and refractory power. My studies focus on teleost fishes, because teleost visual ecology is …
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RATE-LIMITING STEP OF CONE PHOTOTRANSDUCTION RECOVERY AND OGUCHI DISEASE MECHANISMS
… reactions simultaneously. First, the activated opsin must be phosphorylated by G-protein-coupled receptor kinases (GRKs) and capped by arrestin binding. Second, activated transducin must hydrolyze bound GTP through intrinsic GTPase activity, which is accelerated by a GTPase accelerating protein …
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Re-examining the relationships among families of Pectinoidea and molecular machinery of the visual cycle in molluscs
… relationship between genotype and phenotype in opsins by mutating targeted amino acids of interest and examining how these alternations affected opsin function when expressed in vitro. Comparing two closely related scallop retinochromes, I identified and mutated sites lining the binding pocket …
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Structural and Biophysical Characterisation of Denatured States and Reversible Unfolding of Sensory Rhodopsin II
… kinetics for reversible unfolding of sensory rhodopsin II (pSRII), a retinal-binding photophobic receptor from Natronomonas pharaonis. pSRII is difficult to denature, and only SDS can dislodge the retinal chromophore without rapid aggregation. Even in 30% SDS (0.998 $\mathit{\Chi}_{SDS}$), pSRII …
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Development and application of control tools for use in optogenetics research
Optogenetic actuators such as Channelrhodopsin-2 (ChR2) are seven-transmembrane proteins that function as light-gated ion channels. These naturally occurring proteins are found in green algae and serve as sensory photoreceptors controlling phototaxis. Operationally, they contain the …
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Development of next-generation optical neural silencers
… pumps. We characterized a number of novel opsins through an exploration of ecological and genomic diversity, and further boosted opsin function and trafficking through the appendage of signal sequences. The green-light drivable archaerhodopsin-3 (Arch) from Halorubrum sodomense and the …
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Possum magic : exploring colour vision in the common brushtail possum (Trichosurus vulpecula)
… in the common brushtail possum. Using opsin antibodies known to label photoreceptors, I show that brushtail possums have an anatomical basis for at least dichromatic colour vision, with both M/LWS ({u03BB}max = 545nm) and SWS cones present in the retina. There is also a small population …
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