Masters C I, Smith M D, Gutman P D, Minton K W
Department of Pathology, F. Edward Hébert School of Medicine, Uniformed Services University of the Health Sciences, Bethesda, Maryland 20814-4799.
J Bacteriol. 1991 Oct;173(19):6110-7. doi: 10.1128/jb.173.19.6110-6117.1991.
Natural transformation, duplication insertion, and plasmid transformation in Deinococcus radiodurans, a bacterium that contains 4 to 10 chromosomes per cell, were studied. Duplication insertions were often heterozygous, with some chromosomes containing highly amplified insertions and others containing no insertions. Large amplified regions were apparently deleted by intrachromosomal recombination, generating as by-products extrachromosomal circles consisting of multiple tandem repeats of the amplified sequence. The circles were of heterogenous integer sizes, containing as many as 10 or more amplification units. Two strains that are defective in natural transformation and sensitive to DNA-damaging agents were further characterized. Both strains were defective in duplication insertion. While on strain was normal for plasmid transformation, the other was totally defective in this regard, suggesting that plasmid transfer in D. radiodurans may require recombinational functions.
对耐辐射球菌（一种每个细胞含有4至10条染色体的细菌）中的自然转化、重复插入和质粒转化进行了研究。重复插入往往是杂合的，一些染色体含有高度扩增的插入片段，而另一些则没有插入片段。大的扩增区域显然通过染色体内重组被删除，产生由扩增序列的多个串联重复组成的染色体外环状物作为副产物。这些环状物具有不同的整数大小，包含多达10个或更多的扩增单元。对两个自然转化有缺陷且对DNA损伤剂敏感的菌株进行了进一步表征。这两个菌株在重复插入方面都有缺陷。虽然一个菌株的质粒转化正常，但另一个在这方面完全有缺陷，这表明耐辐射球菌中的质粒转移可能需要重组功能。
