UV radiation (UVR) has significant physiological effects on organisms living at or near the Earth's surface, yet the full suite of genes required for fitness of a photosynthetic organism in a UVR-rich environment remains unknown. This study reports a genome-wide fitness assessment of the genes that affect UVR tolerance under environmentally relevant UVR dosages in the model cyanobacterium PCC 7942. Our results highlight the importance of specific genes that encode proteins involved in DNA repair, glutathione synthesis, and the assembly and maintenance of photosystem II, as well as genes that encode hypothetical proteins and others without an obvious connection to canonical methods of UVR tolerance. Disruption of a gene that encodes a leucyl aminopeptidase (LAP) conferred the greatest UVR-specific decrease in fitness. Enzymatic assays demonstrated a strong pH-dependent affinity of the LAP for the dipeptide cysteinyl-glycine, suggesting an involvement in glutathione catabolism as a function of night-time cytosolic pH level. A low differential expression of the LAP gene under acute UVR exposure suggests that its relative importance would be overlooked in transcript-dependent screens. Subsequent experiments revealed a similar UVR-sensitivity phenotype in LAP knockouts of other organisms, indicating conservation of the functional role of LAPs in UVR tolerance.
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http://dx.doi.org/10.1073/pnas.2211789119 | DOI Listing |
Mar Environ Res
January 2025
Instituto de Ciencias Marinas y Limnológicas, Facultad de Ciencias, Universidad Austral de Chile, Valdivia, Chile; Laboratorio Costero de Recursos Acuáticos de Calfuco, Facultad de Ciencias, Universidad Austral de Chile, Valdivia, Chile.
Environmental stress on early life stages has severe consequences for individual performance and population dynamics. The internal incubation process of the symbiotic intertidal anemone Anthopleura hermaphroditica ends when the juveniles leave the gastrovascular cavity of the adult, at which moment they are exposed to a highly stressful environment due to tidal changes and environmental radiation in the Quempillén estuary. To determine the cellular and physiological tolerance capabilities of juvenile anemones to changes in salinity and environmental radiation resulting from the abandonment of the gastrovascular cavity, an experiment with an orthogonal design was performed on individuals exposed to four levels of salinity (30.
View Article and Find Full Text PDFBiomedicines
November 2024
Department of Molecular Medicine, School of Medicine, Kyungpook National University, Daegu 41944, Republic of Korea.
: Ultraviolet radiation (UVR) induces oxidative stress in the skin by generating reactive oxygen species (ROS), which can lead to inflammatory conditions including erythema (a sign of sunburn). This clinical study aims to develop an instrumental evaluation method to determine the minimal erythema dose (MED) for UVR. : Fourteen human subjects aged 27 to 57 years (48.
View Article and Find Full Text PDFCells
February 2024
Institute of Genetics and Biophysics (IGB) "Adriano Buzzati-Traverso", National Research Council (CNR) of Italy, 80131 Naples, Italy.
Glioblastoma (GB) is a rare but extremely aggressive brain tumor that significantly impacts patient outcomes, affecting both duration and quality of life. The protocol established by Stupp and colleagues in 2005, based on radiotherapy and chemotherapy with Temozolomide, following maximum safe surgical resection remains the gold standard for GB treatment; however, it is evident nowadays that the extreme intratumoral and intertumoral heterogeneity, as well as the invasiveness and tendency to recur, of GB are not compatible with a routine and unfortunately ineffective treatment. This review article summarizes the main challenges in the search for new valuable therapies for GB and focuses on the impact that extracellular vesicle (EV) research and exploitation may have in the field.
View Article and Find Full Text PDFJ Photochem Photobiol B
March 2024
Laboratory of Photobiology and Molecular Microbiology, Department of Botany, Institute of Science, Banaras Hindu University, Varanasi 221005, India. Electronic address:
Cyanobacteria are photosynthetic organisms and challenged by large number of stresses, especially by ultraviolet radiation (UVR). UVR primarily impacts lipids, proteins, DNA, photosynthetic performance, which lowers the fitness and production of cyanobacteria. UVR has a catastrophic effect on cyanobacterial cells and eventually leads to cell death.
View Article and Find Full Text PDFSci Total Environ
January 2024
School of Biological Sciences, The University of Queensland, St. Lucia, Queensland 4072, Australia.
Reef-building corals create one of the most biodiverse and economically important ecosystems on the planet. Unfortunately, global coral reef ecosystems experience threats from numerous natural stressors, which are amplified by human activities. One such threat is ultraviolet radiation (UVR) from the sun; a genotoxic stressor that is a double-edged sword for corals as they rely on sunlight for energy.
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