The resistance of three types of Bacillus cereus T spores to ultraviolet radiation corresponded to their dipicolinic acid (DPA) content. Photoprotection against ultraviolet light was observed in DPA-containing spores and in DPA-less spores irradiated through calcium dipicolinate.

Observation of faint diffuse ultraviolet background radiation is a delicate undertaking, given the brightness of the ultraviolet stars against which discrimination is essential. I demonstrate that the technique of tomography is unsuited to this particular task.

Spectral ultraviolet (UV) irradiance, water column attenuation and biological weighting functions for inhibition of phytoplankton photosynthesis have been measured for the Rhode River, a subestuary of the Chesapeake Bay. Together, these measurements can be used to estimate UV effects on water column production, but each factor shows a significant range of variability even just considering summe...

Woody-Karrer, Pearl (Palo Alto Medical Research Foundation, Palo Alto, Calif.) and Joseph Greenberg. Resistance and cross resistance of Escherichia coli S mutants to the radiomimetic agent nitrofurazone. J. Bacteriol. 85:1208-1216. 1963.-Cross-resistance relationships are described for 73 mutants of Escherichia coli strain S selected in one step for resistance to nitrofurazone. The test agents ...

The sun protection factor (SPF) has widely been used to evaluate the protective value of sunscreens. However, SPF only reflects the effectiveness of the sunscreen to protect against acute sunburn which is mainly due to ultraviolet B (UVB) radiation. The deleterious effects of UVB are well known and UVB was believed in the past to be the spectrum responsible for the damages arising from ultravio...

Bees often facilitate pollination of important greenhouse crops. Individual bumblebees Bombus terrestris were therefore tested in an indoor flight arena to evaluate whether or not search time to find flowers was influenced by the inclusion or exclusion of ultraviolet radiation. Plastic model flowers of similar spectral properties to flowers of tomato Lycopersicon esculentum Mill. were used to e...

Rabies virus, exposed to the rays of a mercury vapor lamp under proper conditions, loses virulence yet retains considerable immunizing potency for mice.

Aquatic ecosystems are a key component of the Earth's biosphere. A large number of studies document substantial impact of solar UV radiation on individual species, yet considerable uncertainty remains with respect to assessing impacts on ecosystems. Several studies indicate that the impact of increased UV radiation appears relatively low when considering overall ecosystem response, while, in co...