2,070 research outputs found

    UV/blue light signal transduction regulating gene expression in Phaseolus vulgaris and Arabidopsis thaliana

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    Plants regulate the expression of some genes in response to ultraviolet (UV) and blue light. To investigate the signal transduction pathways regulating UV/blue light regulated gene expression, the effects of specific inhibitors were examined in protoplasts isolated from dark-adapted P. vulgaris leaves and a photomixotrophic Arabidopsis cell culture. Pharmacological studies with P. vulgaris protoplasts indicate that calcium, protein phosphorylation and dephosphorylation and protein synthesis are required for UV-A/blue light regulation of genes encoding the small subunit of ribulose 1,5- bisphosphate carboxylase/oxygenase (rbcS), which is similar to the UV-A/blue and UV-B light signalling components regulating chalcone synthase (CHS) expression in Arabidopsis cells. Further studies were carried out in Arabidopsis cells to characterise the UV-A/blue and UV-B regulation of CHS. A 5 min UV-B illumination, followed by transfer to non-inductive, low fluence rate white light for 6 hours, was sufficient to induce CHS transcripts. In contrast, a one hour UV- A/blue illumination, followed by transfer to non-inductive light for 5 hours was required before any CHS transcript accumulation was detected. This indicates that the two pathways are distinct. However, both the UV-A/blue and UV-B light regulation of gene expression appears to involve plasma membrane redox activity, because the impermeable electron acceptor ferricyanide (FeCN), strongly inhibited UV-A/blue and UV-B phototransduction. Additionally, the flavoprotein inhibitor diphenylene iodonium (DPI), strongly inhibited UV-A/blue and UV-B induced CHS and PAL expression. These results suggest that the phototransduction pathways require at least one flavoprotein-mediated electron transfer step as a signalling component. Expression of the Arabidopsis gene encoding the calmodulin-like protein TOUCH3 (TCH3) is induced by FeCN and DPI. Cells treated with a calcium ionophore were not altered in UV/blue light regulated CHS expression. This indicated that cytosolic calcium increases induced by FeCN and DPI are not inhibiting UV/blue phototransduction. However, UV-A/blue and UV-B light inhibited the ionophore-induced expression of TCH3 in Arabidopsis cells. This implied that UV-A/blue and UV-B light were activating a calcium efflux mechanism, lowering cytosolic calcium concentrations. Therefore, the effect of an inhibitor of calcium-ATPases, erythrosin B (BB), was examined. EB prevented the UV-A/blue light induction of CHS. However, EB had no effect on the UV-B induction of CHS. Further pharmacological studies were carried out to characterise the UV/blue inhibition of TCH3 expression in the presence of ionophore. Transgenic Arabidopsis wild-type and hy4 mutant plants expressing the cytosolic calcium reporter protein, aequorin, were generated. UV-A/blue light induced an increase in aequorin luminescence in both transgenic lines, indicating that UV-A/blue light induces an increase in cytosolic calcium concentration, but this response is not mediated by CRY1.No effect on the regulation of CHS expression by reactive oxygen species (ROS) and scavengers of ROS was observed, suggesting that the production of ROS by plasma membrane redox processes is not a component of the signalling pathways. Interestingly, UV-A/blue and UV-B light strongly induced GST5 transcripts in the cell culture and plants. The experiments described in this thesis are discussed and a hypothesis for the signal transduction processes involved in UV/blue regulated gene expression is presented

    The relationship of self-efficacy to catastrophizing and depressive symptoms in community-dwelling older adults with chronic pain: A moderated mediation model

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    Self-efficacy has been consistently found to be a protective factor against psychological distress and disorders in the literature. However, little research is done on the moderating effect of self-efficacy on depressive symptoms in the context of chronic pain. This cross-sectional study aimed to examine if pain self-efficacy attenuated the direct relationship between pain intensity and depressive symptoms, as well as their indirect relationship through reducing the extent of catastrophizing when feeling pain (moderated mediation). 664 community-dwelling Chinese older adults aged 60–95 years who reported chronic pain for at least three months were recruited from social centers. They completed a battery of questionnaires on chronic pain, pain self-efficacy, catastrophizing, and depressive symptoms in individual face-to-face interviews. Controlling for age, gender, education, self-rated health, number of chronic diseases, pain disability, and pain self-efficacy, pain catastrophizing was found to partially mediate the connection between pain intensity and depressive symptoms. Furthermore, the relationship between pain intensity and depressive symptoms was moderated by pain self-efficacy. Self-efficacy was also found to moderate the relationship between pain intensity and catastrophizing and the moderated mediation effect was confirmed using bootstrap analysis. The results suggested that with increasing levels of self-efficacy, pain intensity’s direct effect on depressive symptoms and its indirect effect on depressive symptoms via catastrophizing were both reduced in a dose-dependent manner. Our findings suggest that pain self-efficacy is a significant protective factor that contributes to psychological resilience in chronic pain patients by attenuating the relationship of pain intensity to both catastrophizing and depressive symptoms

    Different strategies for using topical corticosteroids in people with eczema

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    This is a protocol for a Cochrane Review (Intervention). The objectives are as follows: To establish the effectiveness and safety of different ways of using topical corticosteroids in people with eczema

    Sexual selection protects against extinction

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    Reproduction through sex carries substantial costs, mainly because only half of sexual adults produce offspring. It has been theorised that these costs could be countered if sex allows sexual selection to clear the universal fitness constraint of mutation load. Under sexual selection, competition between (usually) males, and mate choice by (usually) females create important intraspecific filters for reproductive success, so that only a subset of males gains paternity. If reproductive success under sexual selection is dependent on individual condition, which depends on mutation load, then sexually selected filtering through ‘genic capture’ could offset the costs of sex because it provides genetic benefits to populations. Here, we test this theory experimentally by comparing whether populations with histories of strong versus weak sexual selection purge mutation load and resist extinction differently. After evolving replicate populations of the flour beetle Tribolium castaneum for ~7 years under conditions that differed solely in the strengths of sexual selection, we revealed mutation load using inbreeding. Lineages from populations that had previously experienced strong sexual selection were resilient to extinction and maintained fitness under inbreeding, with some families continuing to survive after 20 generations of sib × sib mating. By contrast, lineages derived from populations that experienced weak or non-existent sexual selection showed rapid fitness declines under inbreeding, and all were extinct after generation 10. Multiple mutations across the genome with individually small effects can be difficult to clear, yet sum to a significant fitness load; our findings reveal that sexual selection reduces this load, improving population viability in the face of genetic stress

    The \u3cem\u3eChlamydomonas\u3c/em\u3e Genome Reveals the Evolution of Key Animal and Plant Functions

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    Chlamydomonas reinhardtii is a unicellular green alga whose lineage diverged from land plants over 1 billion years ago. It is a model system for studying chloroplast-based photosynthesis, as well as the structure, assembly, and function of eukaryotic flagella (cilia), which were inherited from the common ancestor of plants and animals, but lost in land plants. We sequenced the ∌120-megabase nuclear genome of Chlamydomonas and performed comparative phylogenomic analyses, identifying genes encoding uncharacterized proteins that are likely associated with the function and biogenesis of chloroplasts or eukaryotic flagella. Analyses of the Chlamydomonas genome advance our understanding of the ancestral eukaryotic cell, reveal previously unknown genes associated with photosynthetic and flagellar functions, and establish links between ciliopathy and the composition and function of flagella

    Representative Landscapes in the Forested Area of Canada

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    Canada is a large nation with forested ecosystems that occupy over 60% of the national land base, and knowledge of the patterns of Canada’s land cover is important to proper environmental management of this vast resource. To this end, a circa 2000 Landsat-derived land cover map of the forested ecosystems of Canada has created a new window into understanding the composition and configuration of land cover patterns in forested Canada. Strategies for summarizing such large expanses of land cover are increasingly important, as land managers work to study and preserve distinctive areas, as well as to identify representative examples of current land-cover and land-use assemblages. Meanwhile, the development of extremely efficient clustering algorithms has become increasingly important in the world of computer science, in which billions of pieces of information on the internet are continually sifted for meaning for a vast variety of applications. One recently developed clustering algorithm quickly groups large numbers of items of any type in a given data set while simultaneously selecting a representative—or “exemplar”—from each cluster. In this context, the availability of both advanced data processing methods and a nationally available set of landscape metrics presents an opportunity to identify sets of representative landscapes to better understand landscape pattern, variation, and distribution across the forested area of Canada. In this research, we first identify and provide context for a small, interpretable set of exemplar landscapes that objectively represent land cover in each of Canada’s ten forested ecozones. Then, we demonstrate how this approach can be used to identify flagship and satellite long-term study areas inside and outside protected areas in the province of Ontario. These applications aid our understanding of Canada’s forest while augmenting its management toolbox, and may signal a broad range of applications for this versatile approach

    LSST: from Science Drivers to Reference Design and Anticipated Data Products

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    (Abridged) We describe here the most ambitious survey currently planned in the optical, the Large Synoptic Survey Telescope (LSST). A vast array of science will be enabled by a single wide-deep-fast sky survey, and LSST will have unique survey capability in the faint time domain. The LSST design is driven by four main science themes: probing dark energy and dark matter, taking an inventory of the Solar System, exploring the transient optical sky, and mapping the Milky Way. LSST will be a wide-field ground-based system sited at Cerro Pach\'{o}n in northern Chile. The telescope will have an 8.4 m (6.5 m effective) primary mirror, a 9.6 deg2^2 field of view, and a 3.2 Gigapixel camera. The standard observing sequence will consist of pairs of 15-second exposures in a given field, with two such visits in each pointing in a given night. With these repeats, the LSST system is capable of imaging about 10,000 square degrees of sky in a single filter in three nights. The typical 5σ\sigma point-source depth in a single visit in rr will be ∌24.5\sim 24.5 (AB). The project is in the construction phase and will begin regular survey operations by 2022. The survey area will be contained within 30,000 deg2^2 with ÎŽ<+34.5∘\delta<+34.5^\circ, and will be imaged multiple times in six bands, ugrizyugrizy, covering the wavelength range 320--1050 nm. About 90\% of the observing time will be devoted to a deep-wide-fast survey mode which will uniformly observe a 18,000 deg2^2 region about 800 times (summed over all six bands) during the anticipated 10 years of operations, and yield a coadded map to r∌27.5r\sim27.5. The remaining 10\% of the observing time will be allocated to projects such as a Very Deep and Fast time domain survey. The goal is to make LSST data products, including a relational database of about 32 trillion observations of 40 billion objects, available to the public and scientists around the world.Comment: 57 pages, 32 color figures, version with high-resolution figures available from https://www.lsst.org/overvie

    Strategies for using topical corticosteroids in children and adults with eczema.

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    BACKGROUND: Eczema is a common skin condition. Although topical corticosteroids have been a first-line treatment for eczema for decades, there are uncertainties over their optimal use. OBJECTIVES: To establish the effectiveness and safety of different ways of using topical corticosteroids for treating eczema. SEARCH METHODS: We searched databases to January 2021 (Cochrane Skin Specialised Register; CENTRAL; MEDLINE; Embase; GREAT) and five clinical trials registers. We checked bibliographies from included trials to identify further trials. SELECTION CRITERIA: Randomised controlled trials in adults and children with eczema that compared at least two strategies of topical corticosteroid use. We excluded placebo comparisons, other than for trials that evaluated proactive versus reactive treatment. DATA COLLECTION AND ANALYSIS: We used standard Cochrane methods, with GRADE certainty of evidence for key findings. Primary outcomes were changes in clinician-reported signs and relevant local adverse events. Secondary outcomes were patient-reported symptoms and relevant systemic adverse events. For local adverse events, we prioritised abnormal skin thinning as a key area of concern for healthcare professionals and patients. MAIN RESULTS: We included 104 trials (8443 participants). Most trials were conducted in high-income countries (81/104), most likely in outpatient or other hospital settings. We judged only one trial to be low risk of bias across all domains. Fifty-five trials had high risk of bias in at least one domain, mostly due to lack of blinding or missing outcome data. Stronger-potency versus weaker-potency topical corticosteroids Sixty-three trials compared different potencies of topical corticosteroids: 12 moderate versus mild, 22 potent versus mild, 25 potent versus moderate, and 6 very potent versus potent. Trials were usually in children with moderate or severe eczema, where specified, lasting one to five weeks. The most reported outcome was Investigator Global Assessment (IGA) of clinician-reported signs of eczema. We pooled four trials that compared moderate- versus mild-potency topical corticosteroids (420 participants). Moderate-potency topical corticosteroids probably result in more participants achieving treatment success, defined as cleared or marked improvement on IGA (52% versus 34%; odds ratio (OR) 2.07, 95% confidence interval (CI) 1.41 to 3.04; moderate-certainty evidence). We pooled nine trials that compared potent versus mild-potency topical corticosteroids (392 participants). Potent topical corticosteroids probably result in a large increase in number achieving treatment success (70% versus 39%; OR 3.71, 95% CI 2.04 to 6.72; moderate-certainty evidence). We pooled 15 trials that compared potent versus moderate-potency topical corticosteroids (1053 participants). There was insufficient evidence of a benefit of potent topical corticosteroids compared to moderate topical corticosteroids (OR 1.33, 95% CI 0.93 to 1.89; moderate-certainty evidence). We pooled three trials that compared very potent versus potent topical corticosteroids (216 participants). The evidence is uncertain with a wide confidence interval (OR 0.53, 95% CI 0.13 to 2.09; low-certainty evidence). Twice daily or more versus once daily application We pooled 15 of 25 trials in this comparison (1821 participants, all reported IGA). The trials usually assessed adults and children with moderate or severe eczema, where specified, using potent topical corticosteroids, lasting two to six weeks. Applying potent topical corticosteroids only once a day probably does not decrease the number achieving treatment success compared to twice daily application (OR 0.97, 95% CI 0.68 to 1.38; 15 trials, 1821 participants; moderate-certainty evidence). Local adverse events Within the trials that tested 'treating eczema flare-up' strategies, we identified only 26 cases of abnormal skin thinning from 2266 participants (1% across 22 trials). Most cases were from the use of higher-potency topical corticosteroids (16 with very potent, 6 with potent, 2 with moderate and 2 with mild). We assessed this evidence as low certainty, except for very potent versus potent topical corticosteroids, which was very low-certainty evidence.  Longer versus shorter-term duration of application for induction of remission No trials were identified. Twice weekly application (weekend, or 'proactive therapy') to prevent relapse (flare-ups) versus no topical corticosteroids/reactive application Nine trials assessed this comparison, generally lasting 16 to 20 weeks. We pooled seven trials that compared weekend (proactive) topical corticosteroids therapy versus no topical corticosteroids (1179 participants, children and adults with a range of eczema severities, though mainly moderate or severe). Weekend (proactive) therapy probably results in a large decrease in likelihood of a relapse from 58% to 25% (risk ratio (RR) 0.43, 95% CI 0.32 to 0.57; 7 trials, 1149 participants; moderate-certainty evidence). Local adverse events We did not identify any cases of abnormal skin thinning in seven trials that assessed skin thinning (1050 participants) at the end of treatment. We assessed this evidence as low certainty. Other comparisons  Other comparisons included newer versus older preparations of topical corticosteroids (15 trials), cream versus ointment (7 trials), topical corticosteroids with wet wrap versus no wet wrap (6 trials), number of days per week applied (4 trials), different concentrations of the same topical corticosteroids (2 trials), time of day applied (2 trials), topical corticosteroids alternating with topical calcineurin inhibitors versus topical corticosteroids alone (1 trial), application to wet versus dry skin (1 trial) and application before versus after emollient (1 trial). No trials compared branded versus generic topical corticosteroids and time between application of emollient and topical corticosteroids. AUTHORS' CONCLUSIONS: Potent and moderate topical corticosteroids are probably more effective than mild topical corticosteroids, primarily in moderate or severe eczema; however, there is uncertain evidence to support any advantage of very potent over potent topical corticosteroids. Effectiveness is similar between once daily and twice daily (or more) frequent use of potent topical corticosteroids to treat eczema flare-ups, and topical corticosteroids weekend (proactive) therapy is probably better than no topical corticosteroids/reactive use to prevent eczema relapse (flare-ups). Adverse events were not well reported and came largely from low- or very low-certainty, short-term trials. In trials that reported abnormal skin thinning, frequency was low overall and increased with increasing potency. We found no trials on the optimum duration of treatment of a flare, branded versus generic topical corticosteroids, and time to leave between application of topical corticosteroids and emollient. There is a need for longer-term trials, in people with mild eczema

    A multicomponent intervention for the management of chronic pain in older adults: study protocol for a randomized controlled trial

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    Background: Studies have shown that physical interventions and psychological methods based on the cognitive behavioral approach are efficacious in alleviating pain and that combining both tends to yield more benefits than either intervention alone. In view of the aging population with chronic pain and the lack of evidence-based pain management programs locally, we developed a multicomponent intervention incorporating physical exercise and cognitive behavioral techniques and examined its long-term effects against treatment as usual (i.e., pain education) in older adults with chronic musculoskeletal pain in Hong Kong. Methods/design: We are conducting a double-blind, cluster-randomized controlled trial. A sample of 160 participants aged ≄ 60 years will be recruited from social centers or outpatient clinics and will be randomized on the basis of center/clinic to either the multicomponent intervention or the pain education program. Both interventions consist of ten weekly sessions of 90 minutes each. The primary outcome is pain intensity, and the secondary outcomes include pain interference, pain persistence, pain self-efficacy, pain coping, pain catastrophizing cognitions, health-related quality of life, depressive symptoms, and hip and knee muscle strength. All outcome measures will be collected at baseline, postintervention, and at 3 and 6 months follow-up. Intention-to-treat analysis will be performed using mixed-effects regression to see whether the multicomponent intervention alleviates pain intensity and associated outcomes over and above the effects of pain education (i.e., a treatment × time intervention effect). Discussion: Because the activities included in the multicomponent intervention were carefully selected for ready implementation by allied health professionals in general, the results of this study, if positive, will make available an efficacious, nonpharmacological pain management program that can be widely adopted in clinical and social service settings and will hence improve older people’s access to pain management services
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