Banerjee M, Chakrabarti A, Acharya D P, Roy A, Chakrabarty A N, Bhattacharyya J, Dastidar S G
Department of Medical Microbiology and Parasitology, Calcutta University College of Medicine, Calcutta 700020, India.
Indian J Exp Biol. 2000 Feb;38(2):160-6.
We have attempted a new evaluation of the process of conjugation in bacteria, because of some basic dissimilarities observed between this and that of eukaryotes, or plants and animals. Reference donor and recipient strains, widely used to prove conjugation in bacteria, were chosen; addition of DNase during the conjugation process, led to an unexpected but highly reproducible increase in the transconjugant colony counts (TCC; ca. > or = 1 log), when compared with that of the controls without DNase. Transconjugants were also obtained when the same live donors were substituted with the UV-killed ones although the TCC was very low initially. Contrarily, donors treated with DNA-intercalating agents, e.g. acridine orange or ethidium bromide, resulted in a complete failure to produce transconjugants. There was a quantitative relationship between the DNase used on donors and levels of DNA sugars/nucleotides/DNA, which possibly resulted from interaction between the DNase and DNA being present/produced on the donor surface. This may be indicative of what may actually happen in the donor-recipient mixtures in the conjugation test proper, where the recipient DNase may activate a donor DNA production cycle. The evidences presented did not suggest that the donor DNA in the conjugation process is actually vestibuled through any intercellular conjugation passages, and is susceptible to the action of DNase or the intercalating dyes.
由于观察到细菌的接合过程与真核生物（即植物和动物）的接合过程存在一些基本差异，我们尝试对细菌的接合过程进行新的评估。我们选择了广泛用于证明细菌接合的参考供体和受体菌株；在接合过程中添加DNA酶，与未添加DNA酶的对照相比，转接合菌落计数（TCC；约>或=1个对数）出现了意想不到但高度可重复的增加。当用紫外线杀死的供体替代相同的活供体时，也获得了转接合体，尽管最初TCC非常低。相反，用DNA嵌入剂（如吖啶橙或溴化乙锭）处理的供体导致完全无法产生转接合体。供体上使用的DNA酶与DNA糖/核苷酸/DNA水平之间存在定量关系，这可能是由于DNA酶与供体表面存在/产生的DNA之间的相互作用所致。这可能表明在适当的接合试验中供体-受体混合物中实际发生的情况，即受体DNA酶可能激活供体DNA产生周期。所提供的证据并不表明接合过程中的供体DNA实际上是通过任何细胞间接合通道传递的，并且易受DNA酶或嵌入染料的作用。
