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Pharmaceuticals (Basel, Switzerland) Sep 2019Successful daylight photodynamic therapy (DPDT) relies on the interaction of light, photosensitisers and oxygen. Therefore, the 'dose' of light that a patient receives... (Review)
Review
Successful daylight photodynamic therapy (DPDT) relies on the interaction of light, photosensitisers and oxygen. Therefore, the 'dose' of light that a patient receives during treatment is a clinically relevant quantity, with a minimum dose for effective treatment recommended in the literature. However, there are many different light measurement methods used in the published literature, which may lead to confusion surrounding reliable and traceable dose measurement in DPDT, and what the most appropriate method of light measurement in DPDT might be. Furthermore, for the majority of practitioners who do not carry out any formal dosimetry and for the patients receiving DPDT, building confidence in the evidence supporting this important treatment option is of key importance. This review seeks to clarify the methodology of DPDT and discusses the literature relating to DPDT dosimetry.
PubMed: 31547141
DOI: 10.3390/ph12040143 -
The Journal of Investigative Dermatology Jul 2022Pigment-producing melanocytes overcome frequent oxidative stress in their physiological role of protecting the skin against the deleterious effects of solar UV...
Pigment-producing melanocytes overcome frequent oxidative stress in their physiological role of protecting the skin against the deleterious effects of solar UV irradiation. This is accomplished by the activity of several endogenous antioxidant systems, including the thioredoxin antioxidant system, in which thioredoxin reductase 1 (TR1) plays an important part. To determine whether TR1 contributes to the redox regulation of melanocyte homeostasis, we have generated a selective melanocytic Txnrd1-knockout mouse model (Txnrd1), which exhibits a depigmentation phenotype consisting of variable amelanotic ventral spotting and reduced pigmentation on the extremities (tail tip, ears, and paws). The antioxidant role of TR1 was further probed in the presence of acute neonatal UVB irradiation, which stimulates melanocyte activation and introduces a spike in oxidative stress in the skin microenvironment. Interestingly, we observed a significant reduction in overall melanocyte count and proliferation in the absence of TR1. Furthermore, melanocytes exhibited an elevated level of UV-induced DNA damage in the form of 8-oxo-2'-deoxyguanosine after acute UVB treatment. We also saw an engagement of compensatory antioxidant mechanisms through increased nuclear localization of transcription factor NRF2. Altogether, these data indicate that melanocytic TR1 positively regulates melanocyte homeostasis and pigmentation during development and protects against UVB-induced DNA damage and oxidative stress.
Topics: Animals; Antioxidants; Melanocytes; Mice; Photobiology; Pigmentation; Thioredoxin Reductase 1; Ultraviolet Rays
PubMed: 35031135
DOI: 10.1016/j.jid.2021.11.030 -
Biomedical Papers of the Medical... Jul 2006Solar light is the primary source of UV radiation for all living systems. UV photons can mediate damage through two different mechanisms, either by direct absorption of... (Review)
Review
Solar light is the primary source of UV radiation for all living systems. UV photons can mediate damage through two different mechanisms, either by direct absorption of UV via cellular chromophores, resulting in excited states formation and subsequent chemical reaction, or by phosensitization mechanisms, where the UV light is absorbed by endogenous (or exogenous) sensitizers that are excited and their further reactions lead to formation of reactive oxygen species (ROS). These highly reactive species can interact with cellular macromolecules such as DNA, proteins, fatty acids and saccharides causing oxidative damage. Direct and indirect injuries result in a number of harmful effects such as disrupted cell metabolism, morphological and ultrastructural changes, attack on the regulation pathways and, alterations in the differentiation, proliferation and apoptosis of skin cells. Processes like these can lead to erythema, sunburn, inflammation, immunosuppression, photoaging, gene mutation, and development of cutaneous malignancies. The endogenous and exogenous mechanisms of skin photoprotection are discussed.
Topics: Humans; Photobiology; Radiation Injuries; Reactive Oxygen Species; Skin; Sunscreening Agents; Ultraviolet Rays
PubMed: 16936899
DOI: 10.5507/bp.2006.003 -
Journal of the American Academy of... Nov 2021
Topics: Humans; Photosensitivity Disorders; Syndrome; Ultraviolet Rays
PubMed: 32896592
DOI: 10.1016/j.jaad.2020.08.119 -
Applied Microbiology and Biotechnology May 2018Regulatable promoters are important genetic tools, particularly for assigning function to essential and redundant genes. They can also be used to control the expression... (Review)
Review
Regulatable promoters are important genetic tools, particularly for assigning function to essential and redundant genes. They can also be used to control the expression of enzymes that influence metabolic flux or protein secretion, thereby optimizing product yield in bioindustry. This review will focus on regulatable systems for use in filamentous fungi, an important group of organisms whose members include key research models, devastating pathogens of plants and animals, and exploitable cell factories. Though we will begin by cataloging those promoters that are controlled by nutritional or chemical means, our primary focus will rest on those who can be controlled by a literal flip-of-the-switch: promoters of light-regulated genes. The vvd promoter of Neurospora will first serve as a paradigm for how light-driven systems can provide tight, robust, tunable, and temporal control of either autologous or heterologous fungal proteins. We will then discuss a theoretical approach to, and practical considerations for, the development of such promoters in other species. To this end, we have compiled genes from six previously published light-regulated transcriptomic studies to guide the search for suitable photoregulatable promoters in your fungus of interest.
Topics: Fungal Proteins; Gene Expression Regulation, Fungal; Genes, Fungal; Light; Neurospora crassa; Promoter Regions, Genetic
PubMed: 29569180
DOI: 10.1007/s00253-018-8887-7 -
IMA Fungus Jun 2011Fungi respond and adapt to many environmental signals including light. The photobiology of fungi has been extensively investigated, but in recent years the...
Fungi respond and adapt to many environmental signals including light. The photobiology of fungi has been extensively investigated, but in recent years the identification of the first fungal photoreceptor, WC-1 in the ascomycete Neurospora crassa, and the discovery that similar photoreceptors are required for photoreception in other ascomycete, basidiomycete and zygomycete fungi has allowed the molecular characterization of light reception and the early steps of signal transduction in a number of model fungi. This contribution is based on presentations made at the Special Interest Group Meeting on "Fungal Photobiology" held during IMC9. The contributions summarize the current status of fungal photobiology in Aspergillus nidulans, Neurospora crassa, Mucor circinelloides, and Coprinopsis cinerea.
PubMed: 22679584
DOI: 10.5598/imafungus.2011.02.01.04 -
The New Phytologist Mar 2013Largely because of concerns regarding global climate change, there is a burgeoning interest in the application of fundamental scientific knowledge in order to better... (Review)
Review
Largely because of concerns regarding global climate change, there is a burgeoning interest in the application of fundamental scientific knowledge in order to better exploit environmental cues in the achievement of desirable endpoints in crop production. Ultraviolet (UV) radiation is an energetic driver of a diverse range of plant responses and, despite historical concerns regarding the damaging consequences of UV-B radiation for global plant productivity as related to stratospheric ozone depletion, current developments representative of a range of organizational scales suggest that key plant responses to UV-B radiation may be exploitable in the context of a sustainable contribution towards the strengthening of global crop production, including alterations in secondary metabolism, enhanced photoprotection, up-regulation of the antioxidative response and modified resistance to pest and disease attack. Here, we discuss the prospect of this paradigm shift in photobiology, and consider the linkages between fundamental plant biology and crop-level outcomes that can be applied to the plant UV-B response, in addition to the consequences for related biota and many other facets of agro-ecosystem processes.
Topics: Agriculture; Conservation of Natural Resources; Crops, Agricultural; Ozone Depletion; Stress, Physiological; Ultraviolet Rays
PubMed: 23363481
DOI: 10.1111/nph.12132 -
Current Opinion in Structural Biology Aug 2016Photosystem I (PSI) is one of the two photosystems in oxygenic photosynthesis, and absorbs light energy to generate reducing power for the reduction of NADP to NADPH... (Review)
Review
Photosystem I (PSI) is one of the two photosystems in oxygenic photosynthesis, and absorbs light energy to generate reducing power for the reduction of NADP to NADPH with a quantum efficiency close to 100%. The plant PSI core forms a supercomplex with light-harvesting complex I (LHCI) with a total molecular weight of over 600kDa. Recent X-ray structure analysis of the PSI-LHCI membrane-protein supercomplex has revealed detailed arrangement of the light-harvesting pigments and other cofactors especially within LHCI. Here we introduce the overall structure of the PSI-LHCI supercomplex, and then focus on the excited energy transfer (EET) pathways from LHCI to the PSI core and photoprotection mechanisms based on the structure obtained.
Topics: Energy Transfer; Light-Harvesting Protein Complexes; Photochemical Processes; Photosystem I Protein Complex; Plants
PubMed: 27131043
DOI: 10.1016/j.sbi.2016.04.004 -
Nutrients Jan 2012The seminal discovery that sunlight was important in the prevention of nutritional rickets was made in 1890 by Theobald A. Palm, a medical missionary who contrasted the... (Review)
Review
The seminal discovery that sunlight was important in the prevention of nutritional rickets was made in 1890 by Theobald A. Palm, a medical missionary who contrasted the prevalence of rickets in northern European urban areas with similar areas in Japan and other tropical countries. He surmised that exposure to sunlight prevented rickets. Over the next 40 years his observation led to an understanding of ultraviolet irradiation and its role in vitamin D synthesis. This opened a new era of appreciation for the curative powers of the sun and "the sunshine vitamin". While Palm's observations were in some ways obscure, they had a potent effect on the development of photobiology.
Topics: Animals; History, 19th Century; History, 20th Century; Humans; Phototherapy; Residence Characteristics; Rickets; Sunlight; Vitamin D Deficiency
PubMed: 22347617
DOI: 10.3390/nu4010042 -
EXCLI Journal 2014
Review
PubMed: 26417286
DOI: No ID Found