Browman Howard I, Vetter Russell D, Rodriguez Carolina Alonso, Cullen John J, Davis Richard F, Lynn Eric, St Pierre Jean-François
Department of Fisheries and Oceans Canada, Maurice-Lamontagne Institute, Mont-Joli, Québec, Canada.
Photochem Photobiol. 2003 Apr;77(4):397-404. doi: 10.1562/0031-8655(2003)077<0397:unddit>2.0.co;2.
In previous work, we evaluated the effects of ultraviolet (UV = 280-400 nm) radiation on the early life stages of a planktonic Calanoid copepod (Calanus finmarchicus Gunnerus) and of Atlantic cod (Gadus morhua). Both are key species in North Atlantic food webs. To further describe the potential impacts of UV exposure on the early life stages of these two species, we measured the wavelength-specific DNA damage (cyclobutane pyrimidine dimer [CPD] formation per megabase of DNA) induced under controlled experimental exposure to UV radiation. UV-induced DNA damage in C. finmarchicus and cod eggs was highest in the UV-B exposure treatments. Under the same spectral exposures, CPD loads in C. finmarchicus eggs were higher than those in cod eggs, and for both C. finmarchicus and cod embryos, CPD loads were generally lower in eggs than in larvae. Biological weighting functions (BWF) and exposure response curves that explain most of the variability in CPD production were derived from these data. Comparison of the BWF revealed significant differences in sensitivity to UV-B: C. finmarchicus is more sensitive than cod, and larvae are more sensitive than eggs. This is consistent with the raw CPD values. Shapes of the BWF were similar to each other and to a quantitative action spectrum for damage to T7 bacteriophage DNA that is unshielded by cellular material. The strong similarities in the shapes of the weighting functions are not consistent with photoprotection by UV-absorbing compounds, which would generate features in BWF corresponding to absorption bands. The BWF reported in this study were applied to assess the mortality that would result from accumulation of a given CPD load: for both C. finmarchicus and cod eggs, an increased load of 10 CPD Mb(-1) of DNA due to UV exposure would result in approximately 10% mortality.
在之前的研究中，我们评估了紫外线（UV = 280 - 400纳米）辐射对浮游哲水蚤（飞马哲水蚤Gunnerus）和大西洋鳕鱼（大西洋鳕）早期生命阶段的影响。这两种生物都是北大西洋食物网中的关键物种。为了进一步描述紫外线暴露对这两个物种早期生命阶段的潜在影响，我们测量了在受控实验性紫外线辐射暴露下诱导产生的波长特异性DNA损伤（每兆碱基DNA的环丁烷嘧啶二聚体[CPD]形成量）。在UV - B暴露处理中，紫外线诱导的飞马哲水蚤和鳕鱼卵中的DNA损伤最高。在相同的光谱暴露条件下，飞马哲水蚤卵中的CPD负荷高于鳕鱼卵，并且对于飞马哲水蚤和鳕鱼胚胎而言，卵中的CPD负荷通常低于幼虫中的。从这些数据得出了解释CPD产生中大部分变异性的生物加权函数（BWF）和暴露响应曲线。BWF的比较揭示了对UV - B敏感性的显著差异：飞马哲水蚤比鳕鱼更敏感，并且幼虫比卵更敏感。这与原始CPD值一致。BWF的形状彼此相似，并且与未被细胞物质屏蔽的T7噬菌体DNA损伤的定量作用光谱相似。加权函数形状的强烈相似性与紫外线吸收化合物的光保护作用不一致，紫外线吸收化合物会在BWF中产生与吸收带相对应的特征。本研究中报告的BWF用于评估给定CPD负荷积累所导致的死亡率：对于飞马哲水蚤和鳕鱼卵而言，由于紫外线暴露导致的DNA的CPD负荷每增加10 CPD Mb(-1)，将导致约10%的死亡率。
