Department of Restorative Dentistry, Oregon Health and Science UniversityPortland, OR, USA.
Department of Pediatric Dentistry, Oregon Health and Science UniversityPortland, OR, USA.
Front Cell Infect Microbiol. 2017 Apr 20;7:139. doi: 10.3389/fcimb.2017.00139. eCollection 2017.
The six species found in the human oral cavity are among the most abundant members of the oral flora, occurring in both supra- and subgingival dental plaque as well as on the oral mucosa. Epidemiological data have also implicated these species in the development of the most common oral diseases. Despite their ubiquity, abundance, and ecological significance, surprisingly little is known about biology, largely due to the difficulties associated with their genetic manipulation. In an effort to improve genetic analyses of species, we isolated a collection of veillonellae from clinical plaque samples and screened for natural competence using a newly developed transformation protocol. Numerous strains of were found to exhibit a natural competence ability that was highly influenced by growth medium composition. By exploiting this ability, we were able to utilize cloning-independent allelic exchange mutagenesis to identify the likely source of DNA uptake machinery within a locus homologous to type II secretion systems (T2SS). Interestingly, natural competence was found to exhibit a clear hierarchy of preference for different sources of DNA (plasmid < PCR product < genomic DNA), which is unlike most naturally competent species. Genomic comparisons with other members of the Veillonellaceae family suggest that natural competence is likely to be widely distributed within this group. To the best of our knowledge, this study is the first demonstration of natural competence and targeted allelic exchange mutagenesis within the entire Veillonellaceae family and demonstrates a simple and rapid method to study genetics.
口腔中发现的六种物种是口腔菌群中最丰富的成员之一，存在于龈上和龈下牙菌斑以及口腔黏膜上。流行病学数据还表明，这些物种与最常见的口腔疾病的发展有关。尽管它们无处不在、数量众多且具有生态意义，但令人惊讶的是，人们对它们的生物学特性知之甚少，这主要是由于它们的遗传操作存在困难。为了改善对 物种的遗传分析，我们从临床斑块样本中分离出了一系列韦荣球菌，并使用新开发的转化方案筛选自然感受态。发现许多 菌株具有自然感受态能力，这种能力受到生长培养基组成的强烈影响。通过利用这种能力，我们能够利用非克隆依赖性等位基因交换诱变来确定与 II 型分泌系统（T2SS）同源的基因座内 DNA 摄取机制的可能来源。有趣的是，发现 自然感受态对不同 DNA 来源（质粒<PCR 产物<基因组 DNA）表现出明显的偏好层次，这与大多数自然感受态物种不同。与韦荣球菌科的其他成员进行基因组比较表明，自然感受态可能在该组中广泛分布。据我们所知，这项研究首次在整个韦荣球菌科中展示了自然感受态和靶向等位基因交换诱变，并展示了一种简单快速的研究 遗传学的方法。
