DNA Damage Induced by Ultraviolet Radiation

Mitchell, David L.

doi:10.1002/3527600906.mcb.200300129

Cited by 3 publications

(6 citation statements)

References 96 publications

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“…PER requires the enzyme CPD photolyase plus photoreactivating radiation (PRR: ultraviolet-A [UV-A, 320 to 400 nm] and/or visible light [400 to 700 nm]). The second most prevalent type of DNA damage from UV-B, the (6-4) pyrimidine-pyrimidone dimer, is much less common but potentially more damaging than the CPD to DNA structure (Mitchell 2004). Photoenzymatic repair of (6-4) dimer lesions has been reported for many organisms; however, the efficiency of (6-4) photolyase is very low compared with CPD photolyase (Mitchell 2004).…”

Section: Introductionmentioning

confidence: 99%

“…The second most prevalent type of DNA damage from UV-B, the (6-4) pyrimidine-pyrimidone dimer, is much less common but potentially more damaging than the CPD to DNA structure (Mitchell 2004). Photoenzymatic repair of (6-4) dimer lesions has been reported for many organisms; however, the efficiency of (6-4) photolyase is very low compared with CPD photolyase (Mitchell 2004). In addition to lightdependent DNA repair, there are multi-step enzymatic repair mechanisms (such as nucleotide excision repair, NER) that do not require light.…”

Section: Introductionmentioning

confidence: 99%

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Photoreactivation in two freshwater ciliates: differential responses to variations in UV-B flux and temperature

Sanders¹,

Macaluso²,

Sardina³

et al. 2005

Aquat. Microb. Ecol.

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The effects of UV-B radiation on 2 ciliate species (Glaucoma sp. and Cyclidium sp.) from a clear oligotrophic lake were examined under laboratory conditions with and without photoreactivating radiation (PRR: UV-A and visible light). Glaucoma sp. was exposed to 3 UV-B intensities at 4 temperatures to simulate a range of environmentally relevant conditions. Population growth of Glaucoma sp. declined with increasing levels of UV-B exposure in treatments receiving PRR; blocking PRR generally resulted in 100% mortality. Occurrence of cyclobutane pyrimidine dimers (CPDs [mb DNA]-1) was significantly reduced in Glaucoma sp. receiving PRR relative to those without PRR. These data indicate that photoenzymatic repair is a major component of UV-B tolerance in Glaucoma. At UV-B levels that Glaucoma sp. tolerated, Cyclidium sp. suffered 100% mortality and accumulated a similar level of CPDs whether or not PRR was blocked. Incubation of the 2 ciliates under UV-transparent and UV-blocking acrylics in the oligotrophic lake confirmed their relative sensitivities to UV radiation (UVR). Photoenzymatic repair in Glaucoma sp. was more efficient at 20°C than at 10, 15 and 25°C. The temperature-dependent nature of photoenzymatic repair underscores the need to consider the interactive effects of temperature and UVR on biota, particularly in the face of global climate change and rising incident UVR due to ozone depletion.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Photoreactivation in two freshwater ciliates: differential responses to variations in UV-B flux and temperature

Sanders¹,

Macaluso²,

Sardina³

et al. 2005

Aquat. Microb. Ecol.

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“…is reliant on PER for sustained survival in UV-Bexposed populations. Although PER is widespread taxonomically (16), its importance relative to dark repair is highly variable for different organisms. PER has been shown to be a particularly important mechanism of DNA repair in several species of amphibians (2), zooplankton (7,12,14), protists (26,31), and bacteria (22).…”

Section: Discussionmentioning

confidence: 99%

“…Both types of damage inhibit DNA replication and transcription and, if not repaired, can lead to inaccurate transmission of genetic information or cell death (19,30). Repair mechanisms that have evolved to correct UVB-induced DNA damage fall into two general categories: dark repair mechanisms, of which nucleotide excision repair (NER) is the most important for UV radiation (UVR) damage in eukaryotes, and photoenzymatic repair (PER) (16,18,19,30,38). NER is a light-independent repair mechanism that cleaves the damaged DNA strand before and after the lesion, resulting in the removal of an oligonucleotide containing the dimer.…”

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confidence: 99%

“…In PER, a photolyase enzyme binds to the UV-generated lesion and uses the energy of light to directly cleave the bond formed between pyrimidine bases (i.e., the dimer) without replacing the nucleotide. Photolyase enzymes require absorption of photoreactivating radiation (PRR) in the visible (400-to 700-nm) and UV-A (320-to 400-nm) parts of the spectrum, with a wavelength for maximum PER efficiency determined to be in the 380-to 440-nm range for some bacteria, yeast, and Euglena (16).…”

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confidence: 99%

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Direct Effects of UV-B Radiation on the Freshwater Heterotrophic NanoflagellateParaphysomonassp

Macaluso

Mitchell

Sanders

2009

Appl Environ Microbiol

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The formation of DNA photoproducts in organisms exposed to ambient levels of UV-B radiation can lead to death and/or reduced population growth in aquatic systems. Dependence on photoenzymatic repair to reverse DNA damage caused by UV-B radiation is demonstrated for Paraphysomonas sp., a member of a widely distributed genus of heterotrophic nanoflagellates. At 20°C, Paraphysomonas sp. was exposed to a range of UV-B intensities encountered in natural systems. Populations of the flagellate survived and grew in a dose-dependent manner, but only when simultaneously exposed to photorepair radiation (PRR). In contrast, flagellates exposed to UV-B at 15°C suffered 100% mortality except at the lowest UV-B level (with PRR) tested, which suggested a photorepair temperature optimum above 15°C. After acute UV-B exposures, DNA damage (measured as the formation of pyrimidine dimers) was reduced only in organisms that underwent subsequent exposure to PRR. Populations kept in the dark after UV-B exposure maintained the initial levels of pyrimidine dimers. These results are the first to demonstrate the reliance of a heterotrophic flagellate on photoenzymatic DNA repair for survival from UV-B exposure.

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Dose dependence of DNA repair in rainbow trout (Oncorhynchus mykiss) larvae exposed to UV-B radiation

Mitchell¹,

Adams‐Deutsch

Olson

2009

Photochem Photobiol Sci

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We examined survival and DNA damage in rainbow trout larvae (Oncorhynchus mykiss) resulting from a range of sublethal to lethal ultraviolet-B exposures in the presence and absence of photoreactivating radiation. We found that after low, sublethal UV-B exposures trout larvae are quite proficient at photoenzymatic repair but that this capacity decreases exponentially with the total incident UV-B dose. The relationship between the dose dependence of PER and trout development and vulnerability in fisheries and in the natural environment are discussed.

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DNA Damage Induced by Ultraviolet Radiation

Cited by 3 publications

References 96 publications

Photoreactivation in two freshwater ciliates: differential responses to variations in UV-B flux and temperature

Photoreactivation in two freshwater ciliates: differential responses to variations in UV-B flux and temperature

Direct Effects of UV-B Radiation on the Freshwater Heterotrophic NanoflagellateParaphysomonassp

Dose dependence of DNA repair in rainbow trout (Oncorhynchus mykiss) larvae exposed to UV-B radiation

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