Londero James Eduardo Lago, Dos Santos Caroline Peripolli, Segatto Ana Lúcia Anversa, Passaglia Schuch André
Department of Biochemistry and Molecular Biology, Federal University of Santa Maria, RS, Brazil; Southern Regional Space Research Center, CRS/INPE-MCTIC, Santa Maria, RS, Brazil.
Department of Biochemistry and Molecular Biology, Federal University of Santa Maria, RS, Brazil.
Ecotoxicol Environ Saf. 2017 Sep;143:12-18. doi: 10.1016/j.ecoenv.2017.05.002. Epub 2017 May 6.
Solar ultraviolet radiation B (UVB) is an important environmental stressor for amphibian populations due to its genotoxicity, especially in early developmental stages. Nonetheless, there is an absence of works focused on the UVB effects on tadpoles' food consumption efficiency. In this work, we investigated the effects of the exposure to a low environmental-simulated dose of UVB radiation on food consumption of tadpoles of the forest specialist Hypsiboas curupi [Hylidae, Anura] species. After UVB treatment tadpoles were divided and exposed to a visible light source or kept in the dark, in order to indirectly evaluate the efficiency of DNA repair performed by photolyases and nucleotide excision repair (NER), respectively. The body mass and the amount of food in tadpoles' guts were verified in both conditions and these data were complemented by the micronuclei frequency in blood cells. Furthermore, the keratinized labial tooth rows were analyzed in order to check for possible UVB-induced damage in this structure. Our results clearly show that the body weight decrease induced by UVB radiation occurs due to the reduction of tadpoles' food consumption. This behavior is directly correlated with the genotoxic impact of UVB light, since the micronuclei frequency significantly increased after treatments. Surprisingly, the results indicate that photoreactivation treatment was ineffective to restore the food consumption activity and body weight values, suggesting a low efficiency of photolyases enzymes in this species. In addition, UVB treatments induced a higher number of breaks in the keratinized labial tooth rows, which could be also associated with the decrease of food consumption. This work contributes to better understand the process of weight loss observed in tadpoles exposed to UVB radiation and emphasizes the susceptibility of forest specialist amphibian species to sunlight-induced genotoxicity.
太阳紫外线B（UVB）由于其遗传毒性，对两栖动物种群来说是一种重要的环境应激源，尤其是在早期发育阶段。尽管如此，目前还缺乏关注UVB对蝌蚪食物消耗效率影响的研究。在这项研究中，我们调查了低环境模拟剂量的UVB辐射暴露对森林特有物种库鲁皮雨蛙（Hypsiboas curupi，雨蛙科，无尾目）蝌蚪食物消耗的影响。UVB处理后，蝌蚪被分开并暴露于可见光源下或置于黑暗中，以便分别间接评估光解酶和核苷酸切除修复（NER）进行DNA修复的效率。在这两种条件下都对蝌蚪的体重和肠道内食物量进行了验证，血细胞中的微核频率数据对这些结果进行了补充。此外，还对角质化的唇齿排进行了分析，以检查该结构是否可能受到UVB诱导的损伤。我们的结果清楚地表明，UVB辐射导致的体重下降是由于蝌蚪食物消耗量减少所致。这种行为与UVB光的遗传毒性影响直接相关，因为处理后微核频率显著增加。令人惊讶的是，结果表明光复活处理无法恢复食物消耗活动和体重值，这表明该物种中光解酶的效率较低。此外，UVB处理导致角质化唇齿排出现更多断裂，这也可能与食物消耗量减少有关。这项研究有助于更好地理解暴露于UVB辐射的蝌蚪体重减轻的过程，并强调了森林特有两栖动物物种对阳光诱导的遗传毒性的易感性。
