Dna Repair and Resistance to Uv-B Radiation in Western Spotted Frogs

Abstract

We assessed DNA repair and resistance to solar radiation in eggs of members of the western spotted frog complex (Rana pretiosa and R. luteiventris), species whose populations are suffering severe range reductions and declines. Specifically, we measured the activity of photoreactivating enzyme (photolyase) in oocytes of spotted frogs. In some species, photoreactivation is the most important mechanism for repair of UV‐damaged DNA. Using field experiments, we also compared the hatching success of spotted frog embryos at natural oviposition sites at three elevations, where some embryos were subjected to ambient levels of UV‐B radiation and others were shielded from UV‐B radiation. Compared with other amphibians, photolyase activities in spotted frogs were relatively high. At all sites, hatching success was unaffected by UV‐B. Our data support the interpretation that amphibian embryos with relatively high levels of photolyase are more resistant to UV‐B radiation than those with lower levels of photolyase. At the embryonic stage, UV‐B radiation does not presently seem to be contributing to the population declines of spotted frogs.

Molecular and sensory mechanisms to mitigate sunlight-induced DNA damage in treefrog tadpoles

“…Despite growing knowledge in the field regarding the impact of UVB radiation on different amphibian species, there are only a few published works concerning the detection of UVB-induced DNA lesions and the efficacy of their removal by amphibian DNA repair mechanisms (Blaustein et al, 1999(Blaustein et al, , 1994Smith et al, 2000;Thurman et al, 2014). It is important to mention that photolyases play the main role in the repair of DNA photoproducts in many aquatic organisms.…”

Effect of exposure of ultraviolet B radiation on two anuran species, Polypedates cruciger and Duttaphrynus melanostictus under empirical conditions

“…Even though, some species such as Oregon cascade amphibians are able to develop normally under intense solar radiation (Kats et al, 2000) but some other species such as R. casecadae and B. boreas suffer high mortality due to radiation (Blaustein et al, 1999). Damage caused by UV radiation is dependent on intrinsic factors such as photolyase levels, egg laying behaviors and pigmentation (Licht and Grant, 1997) and abiotic factors such as water depth, turbidity or vegetation cover, which alter the amount of radiation received by the animals in their habitat.…”

“…Ultraviolet -B radiation present in natural sunlight can increase the mortality and malformation rates in embryos of amphibians (Blaustein et al, 1999). In the early stages UV-B has been reported to cause higher mortality in Bufo boreas and Rana 46 Jayawardena et al cascadae in North America (Blaustein et al, 1994).…”

“…These studies suggest that damage caused by UV radiation in amphibians may differ among species. Amphibians live in habitats which are constantly exposed to UV radiation are more tolerant compared to those exposed to UV intermittently (Blaustein et al, 1999).…”

Enigmatic Faunal Declines at La Selva, Costa Rica: Patterns and Processes in a Collapsing Neotropical Herpetofauna

“…Ultraviolet-B has never been associated with mass mortality events such as those that have been documented in Central America (Lips 1999; and no deformed amphibians have been documented in Central American countries, but UV-B may serve as an important stressor when acting synergistically with other factors (Kiesecker et al 2001). Still, many amphibians exhibit behavioural mechanisms that allow them to avoid UV-B exposure (Han et al 2007) and possess physiological repair mechanisms that reduce damage to affected tissues (Blaustein et al 1999). …”