Ultraviolet (UV) radiation can cause stresses or act as a photoregulatory signal depending on its wavelengths and fluence rates. Although the most harmful effects of UV on living cells are generally attributed to UV-B radiation, UV-A radiation can also affect many aspects of cellular processes. In cyanobacteria, most studies have concentrated on the damaging effect of UV and defense mechanisms ...

The effect of ultraviolet B (UV-B) radiation on the thermal sensitivity of cucumber (Cucumis sativus L.) was studied using UV-B-sensitive cv Poinsett 76 and UV-B-resistant cv Ashley grown under control and elevated (300 mW m-2) UV-B radiation levels. Using both cotyledon and leaf discs, the ability of the tissue to reduce triphenyl tetrazolium chloride (TTC) was determined after treatment at 50...

Pterygium has long been believed to be an environmental disease, Ultraviolet (UV) radiation playing a major role in its development. In examination of more than 100 000 Aborigines and non-Aborigines in rural Australia a strong positive correlation between climatic UV radiation and pterygium prevalence was found, providing further evidence of a causal relationship. In addition interesting differ...

The Antarctic ozone hole is reported to develop annually in Austral spring since the late 1970s and results in increasing irradiances of solar UV-B radiation on the earth’s surface and in the aquatic environment (Farman et al. 1985, Häder et al. 1998). Exposure of organisms to enhanced UV-B radiation results in multiple damage, e.g. dimerisation of DNA molecules, formation of reactive oxygen sp...

DNA damage, provoked by ultraviolet (UV) radiation, evokes a cellular damage response composed of activation of stress signaling and DNA checkpoint functions. These are translated to responses of replicative arrest, damage repair, and apoptosis aimed at cellular recovery from the damage. p53 tumor suppressor is a central stress response protein, activated by multiple endogenous and environmenta...

In late May 2005 unusual high levels of solar ultraviolet radiation were observed over central Europe. In Northern Germany the measured irradiance of erythemally effective radiation exceeded the climatological mean by more than about 20%. An extreme low ozone event for the season coincided with high solar elevation angles and high pressure induced clear sky conditions leading to the highest val...

Various biotic and abiotic factors are known to exert selection pressures on floral traits, but the influence of ultraviolet-B (UV-B) light on the evolution of flower structure remains relatively unexplored. We have examined the effectiveness of flower structure in blocking radiation and the effects of UV-B on pollen viability in 42 species of alpine plants in the Hengduan Mountains, China. Flo...

We experimentally tested the hypothesis that accumulations of dietary compounds such as carotenoids or UVabsorbing mycosporine-like amino acids (MAAs) protect against natural levels of ultraviolet radiation (UVR). A calanoid copepod, Leptodiaptomus minutus, was collected from a relatively UV-transparent lake in Pennsylvania where levels of copepod MAAs and carotenoids vary during the year (MAAs...

A simple dichroic beam splitter capable of separating extreme-ultraviolet (XUV) radiation from high-powered visible and UV laser beams is demonstrated. The device has high XUV reflection efficiency (R approximately 44%) and high damage resistance to intense laser radiation and is therefore applicable to laser-generated XUV radiation sources, including harmonic generation, sum-frequency mixing, ...

Ultraviolet-B (UV-B) radiation can have wide-ranging impacts on plants. UV-B exposure can decrease the rate of photosynthesis, alter pigment concentrations, and damage DNA, proteins, and lipids; however, not all species are equally sensitive. Lemna minor and Spirodela polyrhiza, two sympatric aquatic plants, were exposed to 5 or 11 days of artificial UV-B radiation for 6 hours per day, and moni...