Evaluation of biological and physical protection against nuclease degradation of clay-bound plasmid DNA
Evaluation of biological and physical protection against nuclease degradation of clay-bound plasmid DNA
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DOI：
10.1128/aem.67.1.293-299.2001
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发表时间：
2001-01-01
影响因子：
4.4
通讯作者：
Simonet, P
中科院分区：
文献类型：
--
作者：
Demanèche, S;Jocteur-Monrozier, L;Simonet, P
为了确定细胞外 DNA 在土壤中持久存在的机制，并监测细菌转化是否会在这种环境中发生，我们开发了由吸附在粘土颗粒上的质粒 DNA 组成的人工模型。我们确定，在不断增加的核酸酶浓度范围内，粘土结合的 DNA 受到了物理保护。其保护机制主要与核酸酶在粘土矿物上的吸附有关。通过转化天然感受态变形杆菌不动杆菌菌株 BD413 来监测所得 DNA 的生物潜力，这使我们能够证明吸附的 DNA 仅部分可用于转化。这部分与粘土结合的 DNA 可以被细菌利用，也可以被核酸酶接近，而其余部分则逃脱了转化和降解。最后，转化效率与永存机制有关，同源重组对核酸酶的敏感性不如自主复制，后者需要完整的分子。
In order to determine the mechanisms involved in the persistence of extracellular DNA in soils and to monitor whether bacterial transformation could occur in such an environment, we developed artificial models composed of plasmid DNA adsorbed on clay particles. We determined that clay-bound DNA submitted to an increasing range of nuclease concentrations was physically protected. The protection mechanism was mainly related to the adsorption of the nuclease on the clay mineral. The biological potential of the resulting DNA was monitored by transforming the naturally competent proteobacterium Acinetobacter sp, strain BD413, allowing us to demonstrate that adsorbed DNA was only partially available for transformation. This part of the clay-bound DNA which was available for bacteria, was also accessible to nucleases, while the remaining fraction escaped both transformation and degradation. Finally, transformation efficiency was related to the perpetuation mechanism, with homologous recombination being less sensitive to nucleases than autonomous replication, which requires intact molecules.