Nitrogen-limitation exacerbates the impact of ultraviolet radiation on the coccolithophore Gephyrocapsa oceanica

A competent epidermal barrier is crucial for terrestrial mammals. This barrier must keep in water and prevent entry of noxious stimuli. Most importantly, the epidermis must also be a barrier to ultraviolet radiation (UVR) from the sunlight. Currently, the effects of ultraviolet radiation on epidermal barrier function are poorly understood. However, studies in mice and more limited work in humans suggest that the epidermal barrier becomes more permeable, as measured by increased transepidermal water loss, in response UVR, at doses sufficiently high to induce erythema. The mechanisms may include disturbance in the organisation of lipids in the stratum corneum (the outermost layer of the epidermis) and reduction in tight junction function in the granular layer (the first living layer of the skin). By contrast, suberythemal doses of UVR appear to have positive effects on epidermal barrier function. Topical sunscreens have direct and indirect protective effects on the barrier through their ability to block UV and also due to their moisturising or occlusive effects, which trap water in the skin, respectively. Some topical agents such as specific botanical extracts have been shown to prevent the loss of water associated with high doses of UVR. In this review, we discuss the current literature and suggest that the biology of UVR-induced barrier dysfunction, and the use of topical products to protect the barrier, are areas worthy of further investigation.

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The Impact of Ultraviolet Radiation on the Aetiology and Development of Uveal Melanoma

Cancers ◽

10.3390/cancers13071700 ◽

2021 ◽

Vol 13 (7) ◽

pp. 1700

Author(s):

Melissa Chalada ◽

Charmaine A. Ramlogan-Steel ◽

Bijay P. Dhungel ◽

Christopher J. Layton ◽

Jason C. Steel

Keyword(s):

Risk Factors ◽

Ultraviolet Radiation ◽

Uveal Melanoma ◽

World Health Organisation ◽

World Health ◽

Genetic Mutations ◽

High Incidence ◽

The World ◽

The Impact

Uveal melanoma (UM) is currently classified by the World Health Organisation as a melanoma caused by risk factors other than cumulative solar damage. However, factors relating to ultraviolet radiation (UVR) susceptibility such as light-coloured skin and eyes, propensity to burn, and proximity to the equator, frequently correlate with higher risk of UM. These risk factors echo those of the far more common cutaneous melanoma (CM), which is widely accepted to be caused by excessive UVR exposure, suggesting a role of UVR in the development and progression of a proportion of UM. Indeed, this could mean that countries, such as Australia, with high UVR exposure and the highest incidences of CM would represent a similarly high incidence of UM if UVR exposure is truly involved. Most cases of UM lack the typical genetic mutations that are related to UVR damage, although recent evidence in a small minority of cases has shown otherwise. This review therefore reassesses statistical, environmental, anatomical, and physiological evidence for and against the role of UVR in the aetiology of UM.

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Sunscreen or simulated sweat minimizes the impact of acute ultraviolet radiation on cutaneous microvascular function in healthy humans

Experimental Physiology ◽

10.1113/ep087688 ◽

2019 ◽

Vol 104 (7) ◽

pp. 1136-1146 ◽

Cited By ~ 4

Author(s):

S. Tony Wolf ◽

Craig W. Berry ◽

Anna E. Stanhewicz ◽

Lauren E. Kenney ◽

Sara B. Ferguson ◽

...

Keyword(s):

Ultraviolet Radiation ◽

Microvascular Function ◽

Healthy Humans ◽

The Impact

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Cell responses to the impact of physiological doses of ultraviolet radiation and their modulation by plant polyphenols

Journal of the Belarusian State University Biology ◽

10.33581/2521-1722-2019-2-13-21 ◽

2019 ◽

pp. 13-21

Author(s):

Vladimir A. Kostyuk ◽

Ahmed Albuhaydar ◽

Alla I. Potapovich ◽

Lyudmila G. Korkinа

Keyword(s):

Experimental Data ◽

Ultraviolet Radiation ◽

Signaling Pathways ◽

Polyphenolic Compounds ◽

Plant Polyphenols ◽

Inflammatory Signaling ◽

Cell Responses ◽

Subsequent Exposure ◽

Cultured Human Cells ◽

The Impact

In this study it was investigated the responses of cultured human cells – keratinocytes and fibroblasts to physiological doses of ultraviolet radiation (UVR) applied with or without plant polyphenolic compounds: rutin, quercetin, taxofolin, silybin and baikalein. Experimental data obtained in this work indicate the presence of synergism in the action of physiological doses of UVR and plant polyphenolic compounds on inflammatory signaling pathways in keratinocytes and fibroblasts. It is concluded that the identified synergies can contribute to the adaptation of the skin to subsequent exposure to UVR, and thus be one of the photoprotective mechanisms of the plant polyphenolic compounds.

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Cannabis Yield Increased Proportionally With Light Intensity, but Additional Ultraviolet Radiation Did Not Affect Yield or Cannabinoid Content

10.20944/preprints202103.0327.v1 ◽

2021 ◽

Author(s):

David Llewellyn ◽

Scott Golem ◽

Elizabeth Foley ◽

Steve Dinka ◽

Max Jones ◽

...

Keyword(s):

Ultraviolet Radiation ◽

Harvest Index ◽

Cannabis Sativa ◽

Scientific Evidence ◽

Uv Spectra ◽

Neutral Form ◽

Uv Spectrum ◽

Yield And Quality ◽

Controlled Environments ◽

The Impact

Cannabis (Cannabis Sativa L.) is now legally produced in many regions worldwide. Cannabis flourishes under high light intensities (LI); making it an expensive commodity to grow in controlled environments, despite its exceptionally high market value. It is commonly believed that cannabis secondary metabolite levels may be enhanced both by increasing LI and by exposing crops to ultraviolet radiation (UV). However, there is sparse scientific evidence to guide cultivators. Therefore, the impact of LI and UV on yield and quality must be elucidated to enable cultivators to optimize their lighting protocols. We explored the effects of LI, ranging from 350 to 1400 μmol m-2 s-1 and supplemental UV spectra on cannabis yield and potency. There were no spectrum effects on inflorescence yield, but harvest index under UVA+UVB was reduced slightly (1.6%) vs. the control. Inflorescence yield increased linearly from 19.4 to 57.4 g/plant and harvest index increased from 0.565 to 0.627, as LI increased from 350 to 1400 μmol m-2 s-1. Although there were no UV spectrum effects on total equivalent Δ9-tetrahydrocannabinol (T-THC) content in leaves, the neutral form, THC, was 30% higher in UVA+UVB vs. control. While there were no LI effects on inflorescence T-THC content, the content of the acid form (THCA) increased by 20% and total terpenes content decreased by 20% as LI increased from 350 to 1400 μmol m-2 s-1. High LI can substantially increase cannabis yield and quality, but we found no commercially-relevant benefits of adding supplemental UV radiation to indoor cannabis production.

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The impact of ultraviolet radiation on sunburn-related search activity

Dermatology Online Journal ◽

10.5070/d3238035998 ◽

2017 ◽

Vol 23 (8) ◽

Author(s):

Danielle J Lospinoso ◽

Joshua A Lospinoso ◽

Nathanial R Miletta

Keyword(s):

Ultraviolet Radiation ◽

Search Activity ◽

The Impact

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Cytokinin Dynamics during the Response to Nitrogen in Two Contrasting Plectranthus Genotypes

Journal of the American Society for Horticultural Science ◽

10.21273/jashs.141.3.264 ◽

2016 ◽

Vol 141 (3) ◽

pp. 264-274 ◽

Cited By ~ 1

Author(s):

Ellen T. Paparozzi ◽

Jazbaat K. Chahal ◽

Petre Dobrev ◽

Elizabeth A. Claassen ◽

Walter W. Stroup ◽

...

Keyword(s):

Chlorophyll Content ◽

Nitrogen Limitation ◽

Nitrogen Deficiency ◽

Nitrogen Response ◽

Nitrogen Resupply ◽

Phenotypic Variations ◽

Nitrogen Treatment ◽

Specific Regulation ◽

The Impact ◽

Hydrolysis Of

Nitrogen response was compared in two Plectranthus species, Plectranthus parviflorus and Plectranthus ambiguus, which differ substantially in their phenotypic reaction to nitrogen limitation. The leaves of the former species gradually yellow during the nitrogen stress but are retained on the plant. This species copes with nitrogen deficiency also by gradual hydrolysis of starch grains. The latter species, P. ambiguus, responds by abscission of lower leaves. As plant hormones cytokinins are involved in nitrogen response as well as in regulation of the chlorophyll content, their dynamics were followed to explore the fast responses as well as the impact of nitrogen treatment. Both plant species responded to nitrogen deficiency/supplementation in similar ways, by downregulation and upregulation, respectively, of active cytokinins. However, the different phenotypic reactions imposed by nitrogen limitation were associated with specific regulation of cytokinin pool accompanying the stress response by the two species. The increase of the active cytokinins on nitrogen resupply was faster and stronger in the regreening species, P. parviflorus than in P. ambiguus. However, the P. ambiguus plants maintained higher basal levels of all cytokinin metabolites as well as chlorophyll content when compared with P. parviflorus. Nitrogen deficiency was associated in this species with accumulation of cis-zeatin-type cytokinins, which preceded abscission of lower and later on of middle leaves. The achieved results indicate that phenotypic variations in the response to nitrogen deficiency/supplementation are associated with significant quantitative and qualitative differences in the cytokinin pool.

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