Ambient Solar Radiation‐Induced Photodamage in Marine Bacterioplankton
Ambient Solar Radiation‐Induced Photodamage in Marine Bacterioplankton
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DOI：
10.1111/j.1751-1097.1996.tb03086.x
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发表时间：
1996-09
影响因子：
3.3
通讯作者：
W. Jeffrey;P. Aas;M. Lyons;R. Coffin;R. Pledger;D. Mitchell
中科院分区：
文献类型：
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作者：
W. Jeffrey;P. Aas;M. Lyons;R. Coffin;R. Pledger;D. Mitchell
摘要：最近人们对地球表面某些位置紫外线辐射增加的影响引起了很多关注。人们对紫外线辐射对浮游植物和初级生产的影响进行了广泛的研究，但 UVB 对浮游细菌的影响在很大程度上被忽视了。细菌在营养物质和能量流向更高营养水平的循环中发挥着核心作用，既充当矿化剂又充当高等生物消耗的次级生产者。我们已经开始研究 UVB 在海洋浮游生物群落中诱导 DNA 光损伤的情况，使用高度特异性的放射免疫测定法来测量从墨西哥湾北部采集的样品中的环丁烷嘧啶二聚体。 10 个样本中有 9 个的浮游细菌大小部分 (0.8 μm <120 μm) 存在 DNA 损伤。在 48 小时内，在地表水中的浮游细菌尺寸部分和较大的真核浮游生物尺寸部分中观察到二聚体积累和修复的 Diel 模式。浮游细菌大小部分 DNA 损伤的深度分布似乎取决于地表水混合。地表水域的损害最为严重，随着深度的增加而减少，在平静的海洋中可以检测到 10 m。在温和的海洋中，即使是在海面，也没有观察到损害的净累积。研究发现太阳辐射显着抑制 3H-胸苷和 14C-亮氨酸的掺入。紫外线 B 负责大约一半的 3H-胸苷掺入总抑制，UVA 负责另一半的抑制。绝大多数 14C-亮氨酸掺入抑制是由于 UVB，这表明蛋白质合成受 UVA 的影响较小。结果表明，可以对本地浮游生物群落进行 DNA 损伤的直接测量，并且浮游细菌对 UVB 损伤高度敏感，并且可能作为比其他微生物更敏感的 UVR 应激指标。
Abstract— There has been much recent concern about the effects of increased UV radiation at certain locations on the earth's surface. There have been extensive studies of ultraviolet radiation effects on phytoplankton and primary production, yet the effects of UVB upon bacterioplankton have been largely overlooked. Bacteria play a central role in the cycling of nutrients and energy flow to higher trophic levels, serving as both mineralizers and secondary producers that are consumed by higher organisms. We have begun to investigate the induction of DNA photodamage by UVB in marine planktonic communities using a highly specific radioimmunoassay to measure cyclobutane pyrimidine dimers in samples collected from the northern Gulf of Mexico. DNA damage in the bacterioplankton size‐fraction (0.8 μm <120 μm) in 9 of 10 samples. Diel patterns of dimer accumulation and repair were observed in surface waters over a 48 h period in the bacterioplankton size fraction and in the larger eukaryotic plankton size fraction. Depth profiles of DNA damage in the bacterioplankton size fraction appear to be dependent on surface water mixing. Damage was greatest in surface waters, decreased with depth and could be detected to 10 m in calm seas. No net accumulation of damage was observed in moderate seas, even at the surface. Solar radiation was found to inhibit significantly both 3H‐thymidine and 14C‐leucine incorporation. Ultraviolet B was responsible for approximately half of the total inhibition of 3H‐thymidine incorporation, UVA contributing the other half of the inhibition. The vast majority of 14C‐leucine incorporation inhibition was due to UVB, suggesting that protein synthesis is less affected by UVA. The results demonstrate that direct measures of DNA damage can be made of indigenous planktonic communities and that bacterioplankton are highly susceptible to UVB damage and may serve as a more sensitive indicator of UVR stress than other microorganisms.