Kamat A S, Pradhan D S
Int J Radiat Biol Relat Stud Phys Chem Med. 1987 Jan;51(1):7-18. doi: 10.1080/09553008714550441.
The role of dipicolinic acid (DPA) in determining the resistance of Bacillus cereus spores to u.v. and gamma radiation was investigated. B. cereus BIS-59 spores containing varying amounts of DPA were prepared by appropriate compositional adjustments in the secondary media. Compared with spores containing 6 per cent DPA (dry weight) those containing 0.8 per cent DPA were far more sensitive to u.v. radiation. Similar u.v. radiation sensitivity was also found in respect of a DPA-less mutant of B. cereus T 6A 1. Pre-treatment of DPA deficient spores (of wild type or mutant B. cereus) with DPA or the presence of DPA during irradiation resulted in increased resistance of these spores to u.v. radiation. In the range 0.2 to 1 per cent DPA content of spores of B. cereus BIS-59, a striking inverse relationship could be discerned between the DPA content and the number of spore photo-products (5-thymidyl, 5,6-dihydrothymine) formed in DNA and spore viability. The resistance of B. cereus spores to gamma radiation did not seem to be influenced by their DPA content.
研究了吡啶二羧酸（DPA）在决定蜡样芽孢杆菌孢子对紫外线和γ辐射抗性方面的作用。通过对二次培养基进行适当的成分调整，制备了含有不同量DPA的蜡样芽孢杆菌BIS-59孢子。与含有6%（干重）DPA的孢子相比，含有0.8% DPA的孢子对紫外线辐射更为敏感。在蜡样芽孢杆菌T 6A 1的一个无DPA突变体中也发现了类似的紫外线辐射敏感性。用DPA预处理缺乏DPA的孢子（野生型或蜡样芽孢杆菌突变体）或在辐照期间存在DPA，会导致这些孢子对紫外线辐射的抗性增加。在蜡样芽孢杆菌BIS-59孢子的DPA含量为0.2%至1%的范围内，可以看出DPA含量与DNA中形成的孢子光产物（5-胸腺嘧啶核苷、5,6-二氢胸腺嘧啶）数量和孢子活力之间存在显著的反比关系。蜡样芽孢杆菌孢子对γ辐射的抗性似乎不受其DPA含量的影响。
