Academic literature on the topic 'UVR8'

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Journal articles on the topic "UVR8"

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LeCuyer, Brian E., Alison K. Criss, and H. Steven Seifert. "Genetic Characterization of the Nucleotide Excision Repair System of Neisseria gonorrhoeae." Journal of Bacteriology 192, no. 3 (November 20, 2009): 665–73. http://dx.doi.org/10.1128/jb.01018-09.

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ABSTRACT Nucleotide excision repair (NER) is universally used to recognize and remove many types of DNA damage. In eubacteria, the NER system typically consists of UvrA, UvrB, UvrC, the UvrD helicase, DNA polymerase I, and ligase. In addition, when DNA damage blocks transcription, transcription-repair coupling factor (TRCF), the product of the mfd gene, recruits the Uvr complex to repair the damage. Previous work using selected mutants and assays have indicated that pathogenic Neisseria spp. carry a functional NER system. In order to comprehensively examine the role of NER in Neisseria gonorrhoeae DNA recombination and repair processes, the predicted NER genes (uvrA, uvrB, uvrC, uvrD, and mfd) were each disrupted by a transposon insertion, and the uvrB and uvrD mutants were complemented with a copy of each gene in an ectopic locus. Each uvr mutant strain was highly sensitive to UV irradiation and also showed sensitivity to hydrogen peroxide killing, confirming that all of the NER genes in N. gonorrhoeae are functional. The effect of RecA expression on UV survival was minor in uvr mutants but much larger in the mfd mutant. All of the NER mutants demonstrated wild-type levels of pilin antigenic variation and DNA transformation. However, the uvrD mutant exhibited higher frequencies of PilC-mediated pilus phase variation and spontaneous mutation, a finding consistent with a role for UvrD in mismatch repair. We conclude that NER functions are conserved in N. gonorrhoeae and are important for the DNA repair capabilities of this strict human pathogen.
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Moolenaar, Geri F., Celine Moorman, and Nora Goosen. "Role of the Escherichia coli Nucleotide Excision Repair Proteins in DNA Replication." Journal of Bacteriology 182, no. 20 (October 15, 2000): 5706–14. http://dx.doi.org/10.1128/jb.182.20.5706-5714.2000.

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ABSTRACT DNA polymerase I (PolI) functions both in nucleotide excision repair (NER) and in the processing of Okazaki fragments that are generated on the lagging strand during DNA replication.Escherichia coli cells completely lacking the PolI enzyme are viable as long as they are grown on minimal medium. Here we show that viability is fully dependent on the presence of functional UvrA, UvrB, and UvrD (helicase II) proteins but does not require UvrC. In contrast, ΔpolA cells grow even better when theuvrC gene has been deleted. Apparently UvrA, UvrB, and UvrD are needed in a replication backup system that replaces the PolI function, and UvrC interferes with this alternative replication pathway. With specific mutants of UvrC we could show that the inhibitory effect of this protein is related to its catalytic activity that on damaged DNA is responsible for the 3′ incision reaction. Specific mutants of UvrA and UvrB were also studied for their capacity to support the PolI-independent replication. Deletion of the UvrC-binding domain of UvrB resulted in a phenotype similar to that caused by deletion of the uvrC gene, showing that the inhibitory incision activity of UvrC is mediated via binding to UvrB. A mutation in the N-terminal zinc finger domain of UvrA does not affect NER in vivo or in vitro. The same mutation, however, does give inviability in combination with the ΔpolA mutation. Apparently the N-terminal zinc-binding domain of UvrA has specifically evolved for a function outside DNA repair. A model for the function of the UvrA, UvrB, and UvrD proteins in the alternative replication pathway is discussed.
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Yin, Ruohe, Mariya Y. Skvortsova, Sylvain Loubéry, and Roman Ulm. "COP1 is required for UV-B–induced nuclear accumulation of the UVR8 photoreceptor." Proceedings of the National Academy of Sciences 113, no. 30 (July 12, 2016): E4415—E4422. http://dx.doi.org/10.1073/pnas.1607074113.

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The UV-B photoreceptor UV RESISTANCE LOCUS 8 (UVR8) promotes UV-B acclimation and tolerance in Arabidopsis thaliana. UVR8 localizes to both cytosol and nucleus, but its main activity is assumed to be nuclear. UV-B photoreception stimulates nuclear accumulation of UVR8 in a presently unknown manner. Here, we show that CONSTITUTIVELY PHOTOMORPHOGENIC 1 (COP1) is required for UV-B–induced nuclear accumulation of UVR8, but bypassing the COP1 requirement for UVR8 nuclear accumulation did not rescue the cop1 mutant UV-B phenotype. Using a glucocorticoid receptor (GR)-based fusion protein system to conditionally localize GR-UVR8 to the nucleus, we have demonstrated that both photoactivation and nuclear localization of UVR8 are required for UV-B–induced photomorphogenic responses. In contrast, there was no UV-B response when UV-B–activated UVR8 was artificially retained in the cytosol. In agreement with a predominantly nuclear activity, constitutively active UVR8W285A accumulated in the nucleus also in the absence of UV-B. Furthermore, GR-COP1 expression lines suggested that UV-B–activated UVR8 can be coimported into the nucleus by COP1. Our data strongly support localization of UVR8 signaling in the nucleus and a dual role for COP1 in the regulation of UV-B–induced UVR8 nuclear accumulation and in UVR8-mediated UV-B signaling.
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Rai, Neha, Susanne Neugart, Yan Yan, Fang Wang, Sari M. Siipola, Anders V. Lindfors, Jana Barbro Winkler, et al. "How do cryptochromes and UVR8 interact in natural and simulated sunlight?" Journal of Experimental Botany 70, no. 18 (May 17, 2019): 4975–90. http://dx.doi.org/10.1093/jxb/erz236.

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AbstractCryptochromes (CRYs) and UV RESISTANCE LOCUS 8 (UVR8) photoreceptors perceive UV-A/blue (315–500 nm) and UV-B (280–315 nm) radiation in plants, respectively. While the roles of CRYs and UVR8 have been studied in separate controlled-environment experiments, little is known about the interaction between these photoreceptors. Here, Arabidopsis wild-type Ler, CRYs and UVR8 photoreceptor mutants (uvr8-2, cry1cry2 and cry1cry2uvr8-2), and a flavonoid biosynthesis-defective mutant (tt4) were grown in a sun simulator. Plants were exposed to filtered radiation for 17 d or for 6 h, to study the effects of blue, UV-A, and UV-B radiation. Both CRYs and UVR8 independently enabled growth and survival of plants under solar levels of UV, while their joint absence was lethal under UV-B. CRYs mediated gene expression under blue light. UVR8 mediated gene expression under UV-B radiation, and in the absence of CRYs, also under UV-A. This negative regulation of UVR8-mediated gene expression by CRYs was also observed for UV-B. The accumulation of flavonoids was also consistent with this interaction between CRYs and UVR8. In conclusion, we provide evidence for an antagonistic interaction between CRYs and UVR8 and a role of UVR8 in UV-A perception.
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Podolec, Roman, Kelvin Lau, Timothée B. Wagnon, Michael Hothorn, and Roman Ulm. "A constitutively monomeric UVR8 photoreceptor confers enhanced UV-B photomorphogenesis." Proceedings of the National Academy of Sciences 118, no. 6 (February 4, 2021): e2017284118. http://dx.doi.org/10.1073/pnas.2017284118.

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The plant ultraviolet-B (UV-B) photoreceptor UVR8 plays an important role in UV-B acclimation and survival. UV-B absorption by homodimeric UVR8 induces its monomerization and interaction with the E3 ubiquitin ligase COP1, leading ultimately to gene expression changes. UVR8 is inactivated through redimerization, facilitated by RUP1 and RUP2. Here, we describe a semidominant, hyperactive allele, namely uvr8-17D, that harbors a glycine-101 to serine mutation. UVR8G101S overexpression led to weak constitutive photomorphogenesis and extreme UV-B responsiveness. UVR8G101S was observed to be predominantly monomeric in vivo and, once activated by UV-B, was not efficiently inactivated. Analysis of a UVR8 crystal structure containing the G101S mutation revealed the distortion of a loop region normally involved in stabilization of the UVR8 homodimer. Plants expressing a UVR8 variant combining G101S with the previously described W285A mutation exhibited robust constitutive photomorphogenesis. This work provides further insight into UVR8 activation and inactivation mechanisms and describes a genetic tool for the manipulation of photomorphogenic responses.
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Podolec, Roman, Emilie Demarsy, and Roman Ulm. "Perception and Signaling of Ultraviolet-B Radiation in Plants." Annual Review of Plant Biology 72, no. 1 (June 17, 2021): 793–822. http://dx.doi.org/10.1146/annurev-arplant-050718-095946.

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Ultraviolet-B (UV-B) radiation is an intrinsic fraction of sunlight that plants perceive through the UVR8 photoreceptor. UVR8 is a homodimer in its ground state that monomerizes upon UV-B photon absorption via distinct tryptophan residues. Monomeric UVR8 competitively binds to the substrate binding site of COP1, thus inhibiting its E3 ubiquitin ligase activity against target proteins, which include transcriptional regulators such as HY5. The UVR8–COP1 interaction also leads to the destabilization of PIF bHLH factor family members. Additionally, UVR8 directly interacts with and inhibits the DNA binding of a different set of transcription factors. Each of these UVR8 signaling mechanisms initiates nuclear gene expression changes leading to UV-B-induced photomorphogenesis and acclimation. The two WD40-repeat proteins RUP1 and RUP2 provide negative feedback regulation and inactivate UVR8 by facilitating redimerization. Here, we review the molecular mechanisms of the UVR8 pathway from UV-B perception and signal transduction to gene expression changes and physiological UV-B responses.
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Zhang, Zhenhua, Chenjie Xu, Shiyu Zhang, Chen Shi, Hong Cheng, Hongtao Liu, and Bojian Zhong. "Origin and adaptive evolution of UV RESISTANCE LOCUS 8-mediated signaling during plant terrestrialization." Plant Physiology 188, no. 1 (October 18, 2021): 332–46. http://dx.doi.org/10.1093/plphys/kiab486.

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Abstract UV RESISTANCE LOCUS 8 (UVR8) mediates photomorphogenic responses and acclimation to UV-B radiation by regulating the transcription of a series of transcription factors (TFs). However, the origin and evolution of UVR8-mediated signaling pathways remain largely unknown. In this study, we investigated the origin and evolution of the major components of the UVR8-mediated signaling pathway (UVR8, REPRESSOR OF UV-B PHOTOMORPHOGENESIS [RUP], BRI1-EMS-SUPPRESSOR1 [BES1], BES1-INTERACTING MYC-LIKE 1 (BIM1), WRKY DNA-BINDING PROTEIN 36 (WRKY36), MYB DOMAIN PROTEIN 73/77/13 [MYB73/MYB77/MYB13], and PHYTOCHROME INTERACTING FACTOR 4/5 [PIF4 and PIF5]) using comparative genomics and phylogenetic approaches. We showed that the central regulator UVR8 presented a conservative evolutionary route during plant evolution, and the evolutionary history of downstream negative regulators and TFs was different from that of green plant phylogeny. The canonical UVR8-CONSTITUTIVELY PHOTOMORPHOGENIC 1(COP1)/SUPPRESSOR OF PHYA-105 (SPA)-ELONGATED HYPOCOTYL 5 (HY5)-RUP signaling pathway originated in chlorophytes and conferred green algae the additional ability to cope with UV-B radiation. Moreover, the emergence of multiple UVR8-mediated signaling pathways in charophytes laid the foundations for the cross-talk between UV-B signals and endogenous hormone responses. Importantly, we observed signatures that reflect plant adaptations to high UV-B irradiance in subaerial/terrestrial environments, including positive selection in UVR8 and RUPs and increased copy number of some vital TFs. These results revealed that green plants not only experienced adaptive modifications in the canonical UVR8-COP1/SPA-HY5-RUP signaling pathway, but also diversified their UV-B signal transduction mechanisms through increasing cross-talk with other pathways, such as those associated with brassinosteroids and auxin. This study greatly expands our understanding of molecular evolution and adaptive mechanisms underlying plant UV-B acclimation.
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Díaz-Ramos, L. Aranzazú, Andrew O'Hara, Selvaraju Kanagarajan, Daniel Farkas, Åke Strid, and Gareth I. Jenkins. "Difference in the action spectra for UVR8 monomerisation and HY5 transcript accumulation in Arabidopsis." Photochemical & Photobiological Sciences 17, no. 8 (2018): 1108–17. http://dx.doi.org/10.1039/c8pp00138c.

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Heilmann, Monika, John M. Christie, John T. M. Kennis, Gareth I. Jenkins, and Tilo Mathes. "Photoinduced transformation of UVR8 monitored by vibrational and fluorescence spectroscopy." Photochemical & Photobiological Sciences 14, no. 2 (2015): 252–57. http://dx.doi.org/10.1039/c4pp00246f.

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The plant photoreceptor UVR8 uses tryptophan side chains to absorb UV-B radiation to induce photoprotective responses via a so far unknown molecular signaling mechanism. We investigated structural transformations and quantum efficiency of UVR8 photoactivation by vibrational and fluorescence spectroscopy.
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Camacho, Inês S., Alina Theisen, Linus O. Johannissen, L. Aranzazú Díaz-Ramos, John M. Christie, Gareth I. Jenkins, Bruno Bellina, Perdita Barran, and Alex R. Jones. "Native mass spectrometry reveals the conformational diversity of the UVR8 photoreceptor." Proceedings of the National Academy of Sciences 116, no. 4 (January 4, 2019): 1116–25. http://dx.doi.org/10.1073/pnas.1813254116.

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UVR8 is a plant photoreceptor protein that regulates photomorphogenic and protective responses to UV light. The inactive, homodimeric state absorbs UV-B light, resulting in dissociation into monomers, which are considered to be the active state and comprise a β-propeller core domain and intrinsically disordered N- and C-terminal tails. The C terminus is required for functional binding to signaling partner COP1. To date, however, structural studies have only been conducted with the core domain where the terminal tails have been truncated. Here, we report structural investigations of full-length UVR8 using native ion mobility mass spectrometry adapted for photoactivation. We show that, while truncated UVR8 photoconverts from a single conformation of dimers to a single monomer conformation, the full-length protein exists in numerous conformational families. The full-length dimer adopts both a compact state and an extended state where the C terminus is primed for activation. In the monomer the extended C terminus destabilizes the core domain to produce highly extended yet stable conformations, which we propose are the fully active states that bind COP1. Our results reveal the conformational diversity of full-length UVR8. We also demonstrate the potential power of native mass spectrometry to probe functionally important structural dynamics of photoreceptor proteins throughout nature.
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Dissertations / Theses on the topic "UVR8"

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Rizzini, Luca [Verfasser], and Roman [Akademischer Betreuer] Ulm. "UVR8: a plant UV-B photoreceptor = UVR8: ein pflanzlicher UV-B Photorezeptor." Freiburg : Universität, 2011. http://d-nb.info/1123457891/34.

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Findlay, Kirsten. "UVR8 function in a natural solar environment." Thesis, University of Glasgow, 2016. http://theses.gla.ac.uk/8264/.

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Li, Xiankun. "Dynamics and Mechanism of Light Perception by UV Photoreceptor UVR8." The Ohio State University, 2017. http://rave.ohiolink.edu/etdc/view?acc_num=osu1511801451939622.

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Heilmann, Monika. "Structure-function studies of the UV-B photoreceptor UVR8 in Arabidopsis thaliana." Thesis, University of Glasgow, 2013. http://theses.gla.ac.uk/4067/.

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UV-B radiation is an integral component of natural sunlight reaching the Earth’s surface. Although being a potentially harmful and damaging agent, UV-B is a key environmental signal for plants initiating diverse responses that affect their metabolism, development and viability. The majority of these responses involve the differential regulation of gene expression and all require accurate perception of the effective light quality by a photoreceptor. The recent identification of UV RESISTANCE LOCUS8 (UVR8) as a UV B photoreceptor has been an important milestone in plant UV B research (Rizzini et al., 2011; Christie et al., 2012; Wu et al., 2012). The aim of this study was to investigate how the structure of the UVR8 protein determines its function in the UV-B response in Arabidopsis.
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Ruggiero, Paola. "Analisi funzionale del gene UVR8 e suo ruolo nella risposta delle piante a stress ambientali." Doctoral thesis, Universita degli studi di Salerno, 2015. http://hdl.handle.net/10556/2040.

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2010 - 2011
Plants are sessile organisms and, therefore, are continuously subjected to environmental sub-optimal or stressful conditions. In an arid environment plants are challenging multiple stresses, such, as water shortage, excessive soil salinity, osmotic stress conditions and high light intensity, including an excess of ultraviolet light mainly (UV-B). To overcome these unfavorable conditions, plants have evolved different strategies to adapt to common osmotic stress and high UV-B light. Recently, the UV-B photoreceptor, UVR8 (UV RESISTANCE LOCUS 8), has been identified and its role in the plant response to UV-B largely clarified. Besides its role in UV-B signaling, we have demonstrated that the expression of UVR8 gene is strongly induced by osmotic and salt stress in wild type A. thaliana seedling (Fasano et al., 2014). Moreover, by using a "gain and loss of function" approach we have evidenced a role of the UVR8 gene in plant growth, development and differentiation: UVR8 overexpressing plants have a reduced vegetative growth (minor diameter of the rosette, smaller leaves, height less), while silenced plants are characterized by a higher growth and produce a large number of siliques and seeds (Fasano et al., 2009; 2010), reminiscent of the response SIMR (Stress Induced Morphogenic Response). The UVR8 protein is predominantly localized in the cytoplasm and in response to low UV-B doses only a small fraction monomerizes and translocates to the nucleus, where it acts as a transcriptional activator. Most of the UVR8 protein remains in the cytoplasmic proteins and it might exert additional cellular functions by interacting with other proteins involved in the complex plant response to environmental stresses. This project was aimed at the identification of putative proteins that interact with UVR8 protein, and to establish a functional role of these interactions in plant responses to osmotic stress. The main results are summarized below: 1. by using complementary approaches of proteomics and immunoprecipitation, several potential proteins that interact with the UVR8 protein were identified; in particular, our attention was focused on the proteins APX1 (Ascorbate peroxidase) and GGT1 (glutamate-glyoxylate-aminotransferase), known for their role in the mechanisms of detoxification of H2O2, a reactive oxygen species that accumulates in the plant cell in response to different environmental conditions that generate an oxidative stress; 2. the interaction between APX1-UVR8 and UVR8-GGT1 were confirmed in vivo, by using two different assays: the BiFC and the co-immunoprecipitation; 3. through a functional analysis, it was shown that different levels of the UVR8 protein are associated with a different level of ROS, in response to conditions of osmotic stress, suggesting a possible function associated to the interaction of these between UVR8 e APX1 4. a gene expression analysis of the stress marker gene RD29 and the gene GGT1 in UVR8- knock-out or overexpressing plants was performed, in response to salt stress. These experiments provided an early indication of the effect of different levels of the UVR8 protein on the transcriptional level of these two genes and, more generally, in the global response to salt stress in Arabidopsis plants. Further analyses are required to establish whether the interaction of UVR8 with APX1 or GGT1 might somehow influence their enzymatic activity. In addition, previous studies have shown that UVR8 binds to COP1 (an E3-ubiquitin ligase) and targets negative regulators of the UV-B dependent pathway to proteasome degradation (Huang X et al., 2013). The use of inhibitors of this proteoliytic pathway may contribute to determine whether UVR8 protein can recruit APX or GGT1 proteins in order to stabilize them or target them to the proteolytic degradation in response to direct or osmotic stress derived oxidative stress.
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Kaiserli, Eirini. "Subcellular localisation and functional analysis of UVR8, a UV-B specific signalling component in Arabidopsis." Thesis, University of Glasgow, 2008. http://theses.gla.ac.uk/57/.

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UV-B is an integral component of the daylight spectrum that regulates plant gene expression and development, but very little is known about how plants perceive UV-B. Although UV-B-induced damage and repair have been extensively investigated, the mechanisms by which UV-B is perceived as a signal, which mediates physiological and protective responses is not yet clearly understood neither in mammals, nor in higher plants. Low fluence rates of UV-B induce the expression of genes involved in UV-protective responses such as flavonoid biosynthesis and promote plant survival in UV-B. The aim of this study is to contribute to the elucidation of the signal transduction events that lead to the acclimation of plants in response to non-damaging levels of UV-B (< 3.5 μmol m-2 s-1). In particular, the characterisation of UVR8 (UV-RESISTANCE LOCUS 8), a UV-B specific signalling component, is carried out at the protein level. The function of UVR8 involves the orchestration of the expression of a range of genes mediating vital UV-protective responses, including those encoding light-regulated transcription factors HY5 and HYH, enzymes involved in the phenylpropanoid pathway, antioxidant and stress proteins (Brown et al., 2005). UVR8 shows 30% sequence identity to the human regulator of chromatin condensation (RCC1) but differs both in activity and function. The phenotype of uvr8 mutant plants is characterised by an increased susceptibility to UV-B and the lack of the UV-B-specific induction of genes involved in UV-protection, such as CHS (encoding the flavonoid biosynthetic enzyme chalcone synthase) and the transcription factor HY5. The UVR8-mediated regulation of transcription in response to UV-B seems to occur via the association of UVR8 with chromatin via histones in the promoter region of HY5 (Brown et al., 2005) and other genes involved in light signalling. In this study, further investigation of the mechanism by which UVR8 acts as a UV-B specific signalling component is performed by employing a number of approaches including: spatial, temporal protein analysis, subcellular localisation studies, structure-function analyses, and the yeast-two-hybrid assay for the identification of UVR8 interacting proteins. To study spatial, temporal and wavelength specific UVR8 protein abundance anti-UVR8 peptide antibodies were generated. Western blot analyses showed that UVR8 is ubiquitously expressed in all plant tissues from the very early stages of development and at every light treatment tested (dark, white light, UV-B). The subcellular localisation of UVR8 analysed by confocal fluorescence microscopy revealed that a fusion of UVR8 with green fluorescent protein (GFP) is localised in the cytoplasm and the nucleus of various plant tissues (leaf, hypocotyl, root, flower) and under various light fluence rates and qualities (white, red, UV-A, UV-B). Interestingly, a treatment of low fluence rates of UV-B led to an increase of GFP-UVR8 protein accumulation in the nucleus, which was confirmed by western blot analysis based on protein fractionation studies in wild-type plants. The wavelength specificity, the kinetics and the fluence-rate sensitivity of GFP-UVR8 nuclear accumulation suggest that this response is UV-B specific, rapid (10 min UV-B) and very sensitive to very low fluence rates of UV-B (0.1 μmol m-2 s-1). Protein synthesis does not seem to be involved in this process, as there is no change in the protein levels before and after a UV-B irradiation. To assess the importance of the presence of UVR8 in the nucleus and the cytoplasm of the plant cell, uvr8-1 transgenic plants were produced expressing either constitutively nuclear localised GFP-UVR8 fused to a nuclear localisation signal (NLS), or cytosolically retained GFP-UVR8 fused to a nuclear export signal (NES). Nuclear exclusion of NES-GFP-UVR8 fusion protein was sustained under most light conditions apart from UV-B, which induced nuclear import of the protein. This indicates that the mechanism involved in the nuclear accumulation of UVR8 can overcome an export signal either by masking it or by simply superseding it. Furthermore, the NES-GFP-UVR8 construct was functional after UV-B treatment, since it rescued the mutant uvr8 phenotype. None of the inhibitor treatments tested (staurosporine, cycloheximide, cantharidin) was successful in blocking the UV-B induced nuclear import of NES-GFP-UVR8, although they impaired the UVR8 regulated induction of CHS expression. Thus, no evidence is presented for a specific protein modification, which could control this response. Constitutive nuclear localisation of NLS-GFP-UVR8 had no effect on the function of the protein according to complementation analyses. Furthermore, no change in localisation, fluorescence intensity or protein abundance was observed in response to white light or after a UV-B irradiation. These results indicate that the constitutive nuclear localisation of UVR8 is not sufficient for constitutive activation of UVR8 regulated gene expression and that a UV-B stimulus is still necessary to trigger these responses. Unfortunately, based on the current data it cannot be concluded whether the UV-B signal perception occurs in the nucleus or in the cytosol of the plant cell. To investigate the structure-function relationship within the UVR8 protein, deletion analyses followed by complementation studies in transgenic plants were performed. More specifically, deletion of the first 23 amino acids at the N-terminus of UVR8 impaired its nuclear accumulation in response to UV-B. Deletion of a 27 amino acid region near the C-terminus had no effect on the UV-B dependent re-localisation of the protein, but abolished UVR8 regulated gene expression. In addition, a highly basic sequence at the extreme C-terminal of UVR8, resembling a putative monopartite nuclear localisation signal, was deleted. Subcellular localisation and complementation analyses suggest that this sequence does not serve as a nuclear localisation signal, it is not involved in the UV-B induced nuclear accumulation and its absence does not affect UVR8 protein function. Chromatin immunoprecipitation assays show that none of the regions deleted is required for chromatin association and none of the deletions affects subcellular localisation in white light. In order to identify interacting partners for UVR8, the yeast-two hybrid system was used. Unfortunately no interacting proteins have been identified, neither from a screen, nor by directed-interaction studies. A different approach could be employed in the future involving size exclusion chromatography of protein extracts from plants in order to establish whether UVR8 functions as part of a complex in vivo.
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O'Hara, Andrew. "The importance of specific tryptophans to UVR8 function : an intrinsic chromophore for a UV-B photoreceptor." Thesis, University of Glasgow, 2012. http://theses.gla.ac.uk/4012/.

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Although sessile organisms, unable to run away from danger, plants are well adapted to the potential harmful effects of sunlight’s high energy photons within the UV-B wavelength range (280-315 nm). For instance they are able to, among other things; produce their own sunscreen to counter any damage to their proteins, lipids and DNA. Plants of course depend on light as a source of energy for photosynthesis but also use specific wavelengths within the electromagnetic spectrum in a number of ways to act as an informational signal, including UV-B wavelengths, which can induce photomorphogenic responses that allow adaptation and survival for plants in the ever-changing environmental conditions they inhabit. It is now well established in plants that there are more than two pathways operating in response to different wavelengths and fluence rates of UV-B. In response to high, potentially damaging UV-B levels plants utilize a non-specific pathway which overlaps with other stress pathways such as pathogen attack and wounding by, for example, herbivores. And in response to low non-damaging UV-B levels plants utilize the UV-B specific photomorphogenic pathways which bring about acclimation, preparing the plant for potential higher doses and actively promoting plant survival (Jenkins and Brown, 2007). A number of photoreceptors have been identified in plants which act throughout the electromagnetic spectrum, but only in the last year has one been discovered operating at UV-B wavelengths. In fact until then no UV-B- specific photoreceptor had been found in any organism and it was not known how plants perceive UV-B light to initiate photomorphogenic responses. Over the last decade evidence was mounting in favour of the most upstream component of the UV-B photomorphogenic pathway and the only UV-B specific component, UVR8 (UV-RESISTANCE LOCUS 8) as being a UV-B photoreceptor. Now it has been demonstrated in plants to be a bona fide UV-B photoreceptor and to perceive UV-B by a novel mechanism (Rizzini et al., 2011, Christie et al., 2012, Wu et al., 2012). It has been demonstrated upon UV-B irradiation that UVR8 can dissociate from a homodimer to a monomer in vivo and in vitro. And unlike other conventional photoreceptors, which use a chromophore to detect specific wavelengths of light, UVR8 uses tryptophan residues found within its protein structure to carry out photoperception. When UV-B is detected via specific tryptophan residues found within the dimeric UVR8 protein, the energy is captured and used to cause disruption and breakage of several salt bridges between adjacent homodimers causing monomerization and subsequently leading to interaction with COP1 (CONSTITUTIVELY PHOTOMORPHOGENIC 1), nuclear accumulation and signal transduction (Christie et al., 2012; Wu et al., 2012; Favory et al 2009; Kaiserli and Jenkins 2007; Brown et al., 2005). Once UVR8 is in its active form it can then regulate the transcription of a number of UV-B responsive photomorphogenic genes allowing the plant to acclimate to counteract any future potential damage, which in turn promotes the plant’s survival and reproduction (Brown et al., 2005; Oravecz et al., 2006; Favory et al., 2009). When I first started my studies UVR8 was implicated in UV-B responses but it was unknown if it functioned as a photoreceptor. The purpose of my Ph.D was to determine if UVR8 was a UV-B photoreceptor and if so how it perceives UV-B. And more specifically, to address the question: can tryptophan residues within its structure act as an intrinsic chromophore? To investigate this aim I firstly used site directed mutagenesis to mutate specific and multiple tryptophan residues of the 14 found within UVR8’s structure to alanine, phenylalanine and tyrosine. Then I carried out transient expression studies in Nicotiana benthamiana to determine if the mutant protein tagged to GFP was stable and to determine if its subcellular localisation was affected. These UVR8 Trp mutant variants were further analyzed using yeast 2-hybrid assays (Y2H) to test for interaction with COP1, RUP1/RUP2 (REPRESSOR OF UV-B PHOTOMORPHOGENESIS) and also homodimerization. This allowed me to identify Trp mutant candidates to introduce transgenically into Arabidopsis and test further for their ability to complement the null mutant uvr8-1. The mutants were tested using a number of assays to check for monomer/dimer status, subcellular localisation, protein stability, COP1 interaction, photomorphogenic gene expression, hypocotyl inhibition and chromatin binding. Herein I present in vivo data in yeast and plants which shows, as reported by Rizzini et al. (2011), Christie et al. (2012) and Wu et al. (2012), that specific Trps, mainly W285 and W233 within the triad W233, W285, W337 have key roles in photoreception. W337 has a lesser role. These triad Trps, which are all in the conserved motif GWRHT, have now been shown in the UVR8 crystal structure to be brought into close proximity (Christie et al., 2012, Wu et al., 2012). The W285A mutant did not complement uvr8-1 and the W233A mutant only partially complemented, whereas W337A substantially complemented uvr8-1. And although all three Trp mutants constitutively interact with COP1 in planta before and after UV-B irradiation, this is not sufficient to rescue the uvr8-1 mutant for W285A and W233A, suggesting that although COP1 interaction is required for UV-B specific photomorphogenic responses it is not sufficient to mediate a response. Furthermore, for each of the triad mutants their dimer/monomer status is affected, and W285A is constitutively monomeric without being functional. Therefore, similar to COP1 interaction, monomerization on its own is not sufficient for UVR8 activation. In addition, I show that of the remaining 11 trps left of the 14 in total found within UVR8, some (W39, W144, W352) are important for structure and hence function, and the others (W92, 94, 196, 198, 250, 300, 302, 400) are not essential for function and/or structure. To further support the intrinsic Trp chromophore model of UVR8 I also present an action spectrum for dimer to monomer conversion for pure UVR8 protein in vitro from samples expressed and purified from E.coli. The spectrum closely resembles the absorption spectra of UVR8 and Trp in solution, with a maximum response at 280 nm. Moreover, the action spectrum partially resembles the in vivo UVR8 dependent HY5 (ELONGATED HYPOCOTYL 5) expression action spectrum published previously (Brown et al., 2009), although the in vivo HY5 study shows a substantial response at 300 nm, which this in vitro study lacks. Overall I show the importance of specific Trps to the UV-B photoreceptor UVR8 in yeast and in planta and demonstrate that W285 and W233 in particular are important in allowing UVR8 to function as a photoreceptor by acting as intrinsic chromophores.
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Blair, Cheavar Anthony. "UV-B Light Stimulates an Increase in Phenolic Content in the Model System Brachypodium distachyon After 2 Hours of Exposure." OpenSIUC, 2016. https://opensiuc.lib.siu.edu/theses/2003.

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Ultraviolet –B (UV-B) radiation is an abiotic stress that has significant effects on plant growth, development, and gene regulation. Due to the depletion of the stratospheric ozone layer over the past several decades, the amount of UV-B light that is reaching the earth’s surface has significantly increased. As a result, research over the past few decades on the effects of UV-B light on plant growth, development, and the mechanisms that regulate a plant’s protection and survival against UV-B light has grown greatly. Brachypodium distachyon is a relatively new model system and one that has not been extensively studied. The aim of this study was to determine the UV-B dose time required to elicit a significant increase in phenolic content, while subsequently assessing protein production to qualitatively implicate whether or not the experimental dosage of UV-B administered was initiating a UV-B specific or non-specific response. In addition, this research annotated the genes that encode the protein sequences for UVR8 and CHS proteins to see if B. distachyon possessed the necessary proteins to undergo a UV-B specific response similar to that of Arabidopsis. The results of the study show that in response to artificial UV-B light, the dose time of UV-B required to elicit a significant increase in total phenolic content is 2 hours. The data also shows an increase in total protein content after 4 hours of UV-B exposure. In addition to the metabolic data, computational analysis of chalcone synthase (CHS) and UV-RESISTANCE LOCUS 8 (UVR8) revealed that there are seven genes in B. distachyon that encode the protein transcripts for CHS and CHS-like proteins, and two genes that code for UVR8 proteins. The results of this study suggest that the UV-B dose regimen used in this study may be initiating the non-specific UV-B signaling pathway. In addition, the presence of UVR8 and CHS protein sequences suggest that B. distachyon has the capacity to work through the UV-B specific signaling pathway.
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Albrighton, Rachel Mary. "Mutational analysis of the DNA repair protein, UvrA." Thesis, University of Bristol, 2006. http://hdl.handle.net/1983/9fcda510-baf1-44c9-8eb5-f03b5c5a9ba8.

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PREVOST, DONALD. "Retines artificielles stochastiques : algorithmes et mise en uvre." Paris 11, 1995. http://www.theses.fr/1995PA112505.

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Cette these traite de problemes de vision bas-niveau, lesquels entrent dans la classe des problemes inverses mal-poses au sens mathematique. Leur resolution est envisagee sous l'angle de l'approche bayesienne sur champ de markov. Specifiquement, nous etudions les algorithmes d'optimisation applicables a des fonctions d'energie semi-quadratiques, telles que rencontrees en vision bas-niveau (detection de contours, segmentation des textures, determination de mouvement ou stereovision). Ces energies sont definies sur un champ de markov couple. Notre premier objectif est de determiner des approches algorithmiques avantageuses selon les criteres de l'optimalite de la solution ; de la qualite de la restauration, des perspectives de parallelisation et de realisation materielle. Notre demarche consiste a considerer une tache simple: la restauration d'images avec prise en compte des discontinuites. Nous avons compare differents algorithmes dedies a cette tache, puis nous avons propose une methode stochastique, simple et parallelisable, que nous avons appelee relaxation quasi-statique (rqs). Le second objectif releve de l'implantation materielle optoelectronique. Nous proposons une architecture parallele de mise en uvre pour l'algorithme rqs. Celle-ci reflete la structure du champ de markov couple: elle est base sur l'operation conjuguee d'un reseau de resistance stochastique et d'un module binaire. Afin de demontrer la faisabilite de machines d'optimisation stochastique operant a cadence video, nous avons concu et teste un systeme realisant des calculs de monte-carlo sur le probleme du verre de spin. Ce systeme utilise un circuit integre cmos optoelectronique (collaboration avec l'ief, contrat dret n 92-139) et un generateur optique de figures de speckle
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Books on the topic "UVR8"

1

chet, Caroline Fre. Mettre en ¿uvre le Six Sigma. Paris: E d. d'Organisation, 2005.

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ve, Dewulf Genevie, ed. L' ¿uvre d'art: Balzac, Proust, Rilke. Nancy: Presses universitaires de Nancy, 1993.

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Franzheim, Elizabeth. Elizabeth Franzheim: L' uvre, 1965-1985. Paris: Paris Art Center, 1985.

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Roethlisberger, Marcel. Tout l' uvre peint de Claude Lorrain. Paris: Flammarion, 1986.

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Sidaner, Yann Farinaux-Le. Le Sidaner: L' uvre peint et gravé. (Monaco): A. Sauret, 1989.

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Musée des arts décoratifs (Paris, France). Chefs-d' uvre du Musée des arts décoratifs. Paris: Le Musée des arts décoratifs, 1985.

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Rahaniotis, Angela. Appetizers. Montreal: Brimar, 1995.

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Wegman, William. William Wegman: L'¿uvre photographique = photographic works, 1969-1976. Limoges: Fonds re gional d'art contemporain du Limousin, 1991.

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Stock, Jan van der. Cornelis Matsys, 1510/11-1556/57: Uvre graphique : catalogue d'exposition. Bruxelles: Bibliotheque royale Albert Ier, 1985.

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L'influence de l'histoire contemporaine dans l'¿uvre de Marguerite Yourcenar. Amsterdam: Rodopi, 2008.

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Book chapters on the topic "UVR8"

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Yadav, Shivam, and Neelam Atri. "Discovery of UVR8." In UV-B Radiation, 279–88. Chichester, UK: John Wiley & Sons, Ltd, 2017. http://dx.doi.org/10.1002/9781119143611.ch14.

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Liu, Yan, and Xi Huang. "Isolation of UVR8 Protein Complexes." In Methods in Molecular Biology, 33–40. New York, NY: Springer US, 2021. http://dx.doi.org/10.1007/978-1-0716-1370-2_4.

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Chatterjee, Antra, Alok Kumar Shrivastava, Sonia Sen, Shweta Rai, Shivam Yadav, Ruchi Rai, Shilpi Singh, and LC Rai. "UVR8 Signalling, Mechanism and Integration with other Pathways." In UV-B Radiation, 289–307. Chichester, UK: John Wiley & Sons, Ltd, 2017. http://dx.doi.org/10.1002/9781119143611.ch15.

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Laad, Pratibha, Pinke Patel, and K. N. Guruprasad. "UVR8 Signaling, Mechanism, and Integration with Other Pathways." In Plant Life and Environment Dynamics, 193–221. Singapore: Springer Nature Singapore, 2022. http://dx.doi.org/10.1007/978-981-19-3620-3_10.

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Pandey, Avantika, Deepanshi Jaiswal, Madhoolika Agrawal, and Shashi Bhushan Agrawal. "UVR8 Discovery: A New Vision in UV-B Research." In Plant Life and Environment Dynamics, 183–92. Singapore: Springer Nature Singapore, 2022. http://dx.doi.org/10.1007/978-981-19-3620-3_9.

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Yang, Guoqian, Xiaorui Liu, and Li Lin. "Detection of UVR8 Homodimers and Monomers by Immunoblotting Analysis in." In Methods in Molecular Biology, 83–93. New York, NY: Springer US, 2021. http://dx.doi.org/10.1007/978-1-0716-1370-2_9.

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Singh, Jyoti. "UVR-Induced Skin Cancer." In Skin Aging & Cancer, 41–46. Singapore: Springer Singapore, 2019. http://dx.doi.org/10.1007/978-981-13-2541-0_4.

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Dwivedi, Ashish, Amit Kumar Tripathi, Jyoti Singh, and Manish Kumar Pal. "Ultraviolet Radiation (UVR): An Introduction." In Photocarcinogenesis & Photoprotection, 1–8. Singapore: Springer Singapore, 2018. http://dx.doi.org/10.1007/978-981-10-5493-8_1.

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Chopra, Deepti, Dhanananajay Kumar, Divya Dubey, Jyoti Singh, Ajeet Kumar Srivastav, and Kailash Chand Gupta. "UVR and Vitamin D Synthesis." In Skin Aging & Cancer, 71–78. Singapore: Springer Singapore, 2019. http://dx.doi.org/10.1007/978-981-13-2541-0_7.

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Chopra, Deepti, Jyoti Singh, Ajeet Kumar Srivastav, Divya Dubey, Ratan Singh Ray, and Kailash Chand Gupta. "Protective Role of Phytochemicals Against UVR." In Photocarcinogenesis & Photoprotection, 129–39. Singapore: Springer Singapore, 2018. http://dx.doi.org/10.1007/978-981-10-5493-8_12.

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Conference papers on the topic "UVR8"

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Wang, Xiran, Leiyu Jiang, and Haoru Tang. "New insights of UVB photoreceptor UVR8 physiological function in plants." In GREEN ENERGY AND SUSTAINABLE DEVELOPMENT I: Proceedings of the International Conference on Green Energy and Sustainable Development (GESD 2017). Author(s), 2017. http://dx.doi.org/10.1063/1.4992909.

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Hoblos, Omar I., Matthew W. Sheehan, Devin J. Laferriere, and Chen-Hsiang Yu. "Uvision: a lightweight portable UVR detection system." In 2015 IEEE MIT Undergraduate Research Technology Conference (URTC). IEEE, 2015. http://dx.doi.org/10.1109/urtc.2015.7563743.

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von Maltzan, Kristine, Stephanie H. Shirley, and Donna F. Kusewitt. "Abstract 1516: Melanocyte activation by UVR-induced calprotectin." In Proceedings: AACR 104th Annual Meeting 2013; Apr 6-10, 2013; Washington, DC. American Association for Cancer Research, 2013. http://dx.doi.org/10.1158/1538-7445.am2013-1516.

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Hruska, Zuzana, Haibo Yao, Kevin DiCrispino, Kori Brabham, David Lewis, Jim Beach, Robert L. Brown, and Thomas E. Cleveland. "Hyperspectral imaging of UVR effects on fungal spectrum." In Optics & Photonics 2005, edited by Germar Bernhard, James R. Slusser, Jay R. Herman, and Wei Gao. SPIE, 2005. http://dx.doi.org/10.1117/12.618195.

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Islam, K. Talat S., Myles Cockburn, John M. Peters, Frank D. Gilliland, and Rob McConnell. "Residential UVR Exposure And New-onset Asthma During Adolescence." In American Thoracic Society 2010 International Conference, May 14-19, 2010 • New Orleans. American Thoracic Society, 2010. http://dx.doi.org/10.1164/ajrccm-conference.2010.181.1_meetingabstracts.a3137.

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Russell, John, Glenn Jones, and James Hall. "A New UVR/IRR Coverglass for Triple Junction Cells." In 2006 IEEE 4th World Conference on Photovoltaic Energy Conference. IEEE, 2006. http://dx.doi.org/10.1109/wcpec.2006.279870.

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Huang, Xiyong, Michael D. Protheroe, Ahmed M. Al-Jumaily, and Sharad P. Paul. "The Significance of Hair Thermal Diffusivity on Melanoma Incidence." In ASME 2017 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2017. http://dx.doi.org/10.1115/imece2017-71693.

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There is an increased risk of melanoma in adulthood when a child (pre-puberty) has been exposed to high levels of ultraviolet radiation (UVR). It has also been hypothesized that the childhood body air (vellus hair) plays a role in the increased incidence of melanoma later in life. This is attributed to the fact that the vellus hair has properties and physiology which encourage the transmission of harmful energy into the follicle of the hair and ultimately cause damage to the stem cells in residence there. Later in life these damaged stem cells become involved in the generation of melanomas in the epidermis. It has been debated whether the UVR or the heat generated by it is the main contributor to melanoma occurrence. This research is the first step in investigating this phenomenon by focusing on the contribution of changes in thermal characteristics on the incidence of melanoma. To test the hypothesis that child hair can transmit energy more easily than adult hair the transient electro-thermal technique is used to determine the thermal diffusivity of the hair. This involved subjecting platinum coated hair samples to a current pulse and measuring the subsequent voltage response in the sample. Results show that the child hair has a thermal diffusivity around two times higher than adult hair, thus supporting the hypothesis. Further research will be needed, in particular, quantifying the optical transmission characteristics of child hair compared to adult hair.
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Gies, H. P., Colin R. Roy, S. Toomey, and D. W. Tomlinson. "Australian radiation laboratory (ARL) solar-UVR measurement network: calibation and results." In SPIE's 1994 International Symposium on Optics, Imaging, and Instrumentation, edited by Robert E. Huffman and Christos G. Stergis. SPIE, 1994. http://dx.doi.org/10.1117/12.186621.

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Ayoub, L. M., Brenda Hargreaves, and D. P. Morris. "UVR attenuation in lakes: relative contibutions of dissolved and particulate material." In Ocean Optics XIII, edited by Steven G. Ackleson and Robert J. Frouin. SPIE, 1997. http://dx.doi.org/10.1117/12.266426.

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Diaz, Susana B., Charles R. Booth, Roy Armstrong, Sergio Cabrera, Claudio Cassiccia, Humberto Fuenzalida, Charlotte Lovengreen, et al. "Calibration improvement of the IAI Network for the measurement of UVR: multichannel instruments." In Third International Asia-Pacific Environmental Remote Sensing Remote Sensing of the Atmosphere, Ocean, Environment, and Space, edited by Wei Gao, Jay R. Herman, Guangyu Shi, Kazuo Shibasaki, and James R. Slusser. SPIE, 2003. http://dx.doi.org/10.1117/12.466122.

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Reports on the topic "UVR8"

1

Mora-Pérez, Dora Alicia, Julio Escobar-Potes, Arley Barandica-Villegas, Diana M. Cortázar-Gómez, Johana Andrea Sanabria-Domínguez, and Cristian Camilo Guevara-Acevedo. Boletín Económico Regional: Suroccidente, IV trimestre de 2022. Banco de la República Colombia, March 2023. http://dx.doi.org/10.32468/ber-surocc.tr4-2022.

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En el cuarto trimestre de 2022, la actividad económica de Suroccidente registró un crecimiento anual; aunque, con menor dinámica respecto a los trimestres previos. Los mejores resultados se observaron en la industria manufacturera y los desembolsos de crédito agropecuario de Finagro para estimular este sector, cuya oferta estuvo afectada nuevamente por la intensidad de las precipitaciones y el alto costo de los insumos. Por el contrario, se evidenciaron reducciones en las ventas reales del comercio interno, incluidas las de vehículos nuevos, el transporte, la construcción de edificaciones y la venta de vivienda nueva; en esta última debido al agotamiento de los subsidios a compradores, y a los mayores costos de financiación, tanto en UVR por la alta inflación, como en tasas por la política monetaria. Finalmente, la tasa de desempleo cerró a la baja en las tres ciudades capitales de la región; mientras que, la inflación fue alta al triplicarse los precios de la canasta de alimentos, seguidos del costo de los servicios públicos y de los combustibles.
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Banai, Menachem, and Gary Splitter. Molecular Characterization and Function of Brucella Immunodominant Proteins. United States Department of Agriculture, July 1993. http://dx.doi.org/10.32747/1993.7568100.bard.

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The BARD project was a continuation of a previous BARD funded research project. It was aimed at characterization of the 12kDa immunodominant protein and subsequently the cloning and expression of the gene in E. coli. Additional immunodominant proteins were sought among genomic B. abortus expression library clones using T-lymphocyte proliferation assay as a screening method. The 12kDa protein was identified as the L7/L12 ribosomal protein demonstrating in the first time the role a structural protein may play in the development of the host's immunity against the organism. The gene was cloned from B. abortus (USA) and B. melitensis (Israel) showing identity of the oligonucleotide sequence between the two species. Further subcloning allowed expression of the protein in E. coli. While the native protein was shown to have DTH antigenicity its recombinant analog lacked this activity. In contrast the two proteins elicited lymphocyte proliferation in experimental murine brucellosis. CD4+ cells of the Th1 subset predominantly responded to this protein demonstrating the development of protective immunity (g-IFN, and IL-2) in the host. Similar results were obtained with bovine Brucella primed lymphocytes. UvrA, GroE1 and GroEs were additional Brucella immunodominant proteins that demonstrated MHC class II antigenicity. The role cytotoxic cells are playing in the clearance of brucella cells was shown using knock out mice defective either in their CD4+ or CD8+ cells. CD4+ defective mice were able to clear brucella as fast as did normal mice. In contrast mice which were defective in their CD8+ cells could not clear the organisms effectively proving the importance of this subtype cell line in development of protective immunity. The understanding of the host's immune response and the expansion of the panel of Brucella immunodominant proteins opened new avenues in vaccine design. It is now feasible to selectively use immunodominant proteins either as subunit vaccine to fortify immunity of older animals or as diagnostic reagents for the serological survaillance.
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