Flow cytometry analysis of changes in the DNA content of the polychlorinated biphenyl degrader Comamonas testosteroni TK102:: Effect of metabolites on cell-cell separation
Flow cytometry analysis of changes in the DNA content of the polychlorinated biphenyl degrader Comamonas testosteroni TK102:: Effect of metabolites on cell-cell separation
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DOI：
10.1128/aem.68.10.5104-5112.2002
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发表时间：
2002-10-01
影响因子：
4.4
通讯作者：
Kimbara, K
中科院分区：
文献类型：
--
作者：
Hiraoka, Y;Yamada, T;Kimbara, K
采用流式细胞仪检测了睾丸酮丛毛单胞菌TK 102在多氯联苯（PCB）存在或不存在条件下生长过程中DNA含量的变化。在无多氯联苯的培养基中，大多数稳定期细胞含有一条染色体。在多氯联苯的存在下，含有两条染色体的细胞的百分比从12%增加到约50%。相比之下，除了多氯联苯没有改变DNA含量的三个物种，不能降解多氯联苯。此外，不被TK 102降解的高氯化多氯联苯不会导致DNA含量的变化。这些结果表明，多氯联苯并没有直接影响细胞的DNA含量，而是由多氯联苯降解产生的中间代谢产物引起的DNA含量的增加。为了研究中间代谢产物对细胞DNA含量的影响，通过基因置换破坏了四个bph基因，bphA 1，bphB，bphC和bphD。由此产生的突变株积累的中间代谢产物时，他们生长在多氯联苯或联苯（BP）的存在下。当bphB基因被破坏时，含有两条染色体的细胞的百分比在与多氯联苯或BP一起生长的培养物中增加。当与BP一起生长时，该突变体的培养物积累了两种中间代谢物，2-羟基联苯（2-OHBP）和3-OHBP。在野生型TK 102和非PCB降解物种培养物中加入2-或3-OHBP也导致含有两条染色体的细胞百分比增加。电子显微镜显示，细胞-细胞分离被抑制在这种文化。这是首次报道羟基-BPs可以抑制细菌细胞分离，同时允许持续的DNA复制。
Flow cytometry was used to monitor changes in the DNA content of the polychlorinated biphenyl (PCB)degrading bacterium Comamonas testosteroni TK102 during growth in the presence or absence of PCBs. In culture medium without PCBs, the majority of stationary-phase cells contained a single chromosome. In the presence of PCBs, the percentage of cells containing two chromosomes increased from 12% to approximately 50%. In contrast, addition of PCBs did not change the DNA contents of three species that are unable to degrade PCBs. In addition, highly chlorinated PCBs that are not degraded by TK102 did not result in a change in the DNA content. These results suggest that PCBs did not affect the DNA content of the cells directly; rather, the intermediate metabolites resulting from the degradation of PCBs caused the increase in DNA content. To study the effect of intermediate metabolites on the DNA content of the cells, four bph genes, bphA1, bphB, bphC, and bphD, were disrupted by gene replacement. The resulting mutant strains accumulated intermediate metabolites when they were grown in the presence of PCBs or biphenyl (BP). When the bphB gene was disrupted, the percentage of cells containing two chromosomes increased in cultures grown with PCBs or BP. When grown with BP, cultures of this mutant accumulated two intermediate metabolites, 2-hydroxybiphenyl (2-OHBP) and 3-OHBP. Addition of 2- or 3-OHBP to a wild-type TK102 and non-PCB-degrading species culture also resulted in an increase in the percentage of cells containing two chromosomes. Electron microscopy revealed that cell-cell separation was inhibited in this culture. This is the first report that hydroxy-BPs can inhibit bacterial cell separation while allowing continued DNA replication.