Harm H
Mutat Res. 1980 Jan;69(1):167-76. doi: 10.1016/0027-5107(80)90186-4.
Cultured cells of placental mammals (including human skin fibroblasts) as well as fresh cornea tissue from oxen have been UV (254 nm)-irradiated and either kept dark or exposed to photoreactivating light (wavelengths greater than 375 nm only) prior to extraction of their DNA. The latter was added to an in vitro photorepair system consisting of UV-irradiated DNA from Haemophilus influenzae and yeast-photoreactiving enzyme, illuminated with broad-spectrum white fluorescent light. The extent of competitive inhibition of the in vitro photorepair of Haemophilus-DNA, resulting from the addition of mammalian DNA, has been taken as a measure of mammalian DNA lesions capable of reacting with photoreactivating enzyme. In most cases the amount of these DNA lesions was reduced if the UV-irradiated mammalian cells had been light-exposed prior to DNA extraction, indicating photoenzymatic repair of up to 90% of the lesions. DNA damage by the photoreactivating light itself was observed at varying degrees in human cells, where this effect presumably masks some of the photorepair.
对胎盘哺乳动物（包括人类皮肤成纤维细胞）的培养细胞以及来自牛的新鲜角膜组织进行紫外线（254纳米）照射，并在提取其DNA之前，要么保持黑暗，要么暴露于光复活光（仅波长大于375纳米）下。将后者添加到一个体外光修复系统中，该系统由来自流感嗜血杆菌的紫外线照射DNA和酵母光复活酶组成，用广谱白色荧光灯照射。由添加哺乳动物DNA导致的对流感嗜血杆菌DNA体外光修复的竞争抑制程度，已被用作衡量能够与光复活酶反应的哺乳动物DNA损伤的指标。在大多数情况下，如果紫外线照射的哺乳动物细胞在DNA提取之前已暴露于光下，这些DNA损伤的数量会减少，这表明高达90%的损伤得到了光酶修复。在人类细胞中不同程度地观察到了光复活光本身造成的DNA损伤，这种效应可能掩盖了一些光修复。
