Aquatic organisms, ranging from bacteria to fish, living in clear lakes are presently receiving damaging levels of UV radiation. Photoreactivation is a light-dependent mechanism by which some organisms deal with DNA damage caused by UV radiation. Yet, photoreactivation is a mechanism that confounds long-term predictive modeling of UV effects on the survival of these organisms. Here we show that...

The larvae of most coral species spend some time in the plankton, floating just below the surface and hence exposed to high levels of ultraviolet radiation (UVR). The high levels of UVR are potentially stressful and damaging to DNA and other cellular components, such as proteins, reducing survivorship. Consequently, mechanisms to either shade (prevent) or repair damage potentially play an impor...

Three independently isolated ultraviolet light-sensitive (uvs) mutants of Anacystis nidulans were characterized. Strain uvs-1 was most sensitive to UV in the absence of photoreactivation. Pretreatment with caffeine suppressed the dark-survival curve of strain uvs-1, indicating the presence of excision enzymes involved in dark repair. Under "black" and "white" illumination, strain uvs-1 displays...

To determine if an Antarctic species repairs DNA at rates equivalent to warmer water equivalents, we examined repair of UV-damaged DNA in echinoid embryos and larvae. DNA repair by photoreactivation was compared in three species Sterechinus neumayeri (Antarctica), Evechinus chloroticus (New Zealand) and Diadema setosum (Tropical Australia) spanning a latitudinal gradient from polar (77.86 degre...

1. The amount of visible or long ultraviolet light (UV) required to photoreactivate Colpidium colpoda injured with known dosages of short UV (2654 A) was determined. 2. The effect of the short UV was tested by the delay in division of exposed animals compared to controls. Photoreactivation was tested by the effect of postillumination on the delay of division of treated colpidia compared to cont...

The effects of UV irradiation (254 mmu) on a coccoid blue-green alga Agmenellum quadruplicatum, Strain PR-6, have been examined in terms of the survival curve and measurement of short time photosynthetic rates. From study of survival evidence has been found for a strong photoreactivation centered near 430 mmu. Measurements of photosynthetic rate suggest that there is a correlation between decay...

background: photoreactivation of microorganisms following uv disinfection is a disadvantage of using uv technology for wastewater treatment, since in some cases it may even reach several logarithms. the aim of this study was to evaluate the possibility of the photoreactivation of indicator bacteria (coliform and streptococci) in the irradiated effluent. methods: this study was performed using t...

Photoreactivation is a DNA repair pathway that requires the presence of a photoreactivating enzyme, DNA photolyase. DNA photolyase recognizes and binds specifically to ultraviolet radiation (UVR)-induced cyclobutane pyrimidine dimers in DNA. Exposure of the photolyase-dimer complex to wavelengths in the range of 300-500 nm results, upon absorption of a photon, in the return of the dimerized pyr...

Three independently isolated ultraviolet light-sensitive (uvs) mutants of Anacystis nidulans were characterized. Strain uvs-1 was most sensitive to UV in the absence of photoreactivation. Pretreatment with caffeine suppressed the dark-survival curve of strain uvs-1, indicating the presence of excision enzymes involved in dark repair. Under "black" and "white" illumination, strain uvs-1 displays...