Tuveson R W, Wang G R, Becker R S
Department of Microbiology, University of Illinois, Urbana 61801.
Photochem Photobiol. 1992 Sep;56(3):341-52. doi: 10.1111/j.1751-1097.1992.tb02169.x.
The phototoxicity of 8-methoxythionepsoralen (8-MOTP) and 6-methylthione coumarin (6-MTC) when activated by UV-A has been investigated using a variety of Escherichia coli strains, Haemophilus influenzae transforming DNA and Escherichia coli pBR322 plasmid DNA. The results demonstrate that 8-MOTP is a strictly oxygen independent photosensitizer that is about 500-fold less efficient in forming lesions leading to equivalent lethality than is the parent compound from which it is derived (8-MOP). As is true for 8-MOP, 8-MOTP is capable of inducing histidine independent mutations in E. coli and inactivating transforming DNA consistent with DNA being a target for lesions induced by this molecule in the presence of UV-A. 6-MTC is a strongly oxygen dependent photosensitizer activated by UV-A when tested with either E. coli cells or transforming DNA in contrast to the parent compound (6-methylcoumarin; 6-MC) which is not phototoxic when treated with UV-A. These results imply that the membrane may be an important target leading to lethality. 6-MTC in the presence of UV-A can inactivate pBR322 plasmid and Haemophilus influenzae transforming DNA activity in vitro suggesting that DNA is a potential target for this molecule when activated by UV-A.
利用多种大肠杆菌菌株、流感嗜血杆菌转化DNA以及大肠杆菌pBR322质粒DNA，研究了8-甲氧基硫代补骨脂素（8-MOTP）和6-甲基硫代香豆素（6-MTC）在紫外线A（UV-A）激活下的光毒性。结果表明，8-MOTP是一种严格依赖氧气的光敏剂，与它所衍生的母体化合物（8-MOP）相比，在形成导致同等致死率的损伤方面效率低约500倍。与8-MOP一样，8-MOTP能够在大肠杆菌中诱导组氨酸非依赖型突变，并使转化DNA失活，这与DNA是该分子在UV-A存在下诱导损伤的靶点一致。与母体化合物（6-甲基香豆素；6-MC）不同，6-MC经UV-A处理时无光毒性，而6-MTC在用大肠杆菌细胞或转化DNA进行测试时是一种由UV-A激活的强氧依赖性光敏剂。这些结果表明，细胞膜可能是导致致死的重要靶点。在UV-A存在下，6-MTC能够使pBR322质粒和流感嗜血杆菌转化DNA的体外活性失活，这表明DNA是该分子在被UV-A激活时的潜在靶点。
