Cooperative Research Centre for Oral Health Science, Melbourne Dental School, Bio21 Institute, The University of Melbourne, Australia.
Microbiology (Reading). 2010 Mar;156(Pt 3):774-788. doi: 10.1099/mic.0.033654-0. Epub 2009 Dec 10.
Treponema denticola is an oral spirochaete that has been strongly associated with chronic periodontitis. The bacterium exists as part of a dense biofilm (subgingival dental plaque) accreted to the tooth. To determine T. denticola gene products important for persistence as a biofilm we developed a continuous-culture biofilm model and conducted a genome-wide transcriptomic analysis of biofilm and planktonic cells. A total of 126 genes were differentially expressed with a fold change of 1.5 or greater. This analysis identified the upregulation of putative prophage genes in the T. denticola 35405 genome. Intact bacteriophage particles were isolated from T. denticola and circular phage DNA was detected by PCR analysis. This represents the first, to our knowledge, functional bacteriophage isolated from T. denticola, which we have designated varphitd1. In biofilm cells there was also an upregulation of genes encoding several virulence factors, toxin-antitoxin systems and a family of putative transposases. Together, these data indicate that there is a higher potential for genetic mobility in T. denticola when growing as a biofilm and that these systems are important for the biofilm persistence and therefore virulence of this bacterium.
齿密螺旋体是一种口腔螺旋体，与慢性牙周炎有很强的关联。这种细菌存在于附着在牙齿上的密集生物膜（龈下牙菌斑）中。为了确定齿密螺旋体作为生物膜持续存在的重要基因产物，我们开发了一种连续培养生物膜模型，并对生物膜和浮游细胞进行了全基因组转录组分析。共有 126 个基因的表达水平发生了 1.5 倍或更高的差异变化。该分析鉴定了齿密螺旋体 35405 基因组中假定的前噬菌体基因的上调。从齿密螺旋体中分离出完整的噬菌体颗粒，并通过 PCR 分析检测到环状噬菌体 DNA。这代表了我们所知的第一个从齿密螺旋体中分离出来的功能噬菌体，我们将其命名为 varphitd1。在生物膜细胞中，还上调了编码几种毒力因子、毒素-抗毒素系统和一组假定转座酶的基因。这些数据表明，当齿密螺旋体作为生物膜生长时，其遗传可移动性的潜力更高，这些系统对于生物膜的持久性以及该细菌的毒力非常重要。
