ABSTRACT

Bacteriophage T4 RNA ligase 1 (T4 Rnl1) can be stably expressed in many bacteria and has been reported to affect the bioactivity of the host bacteria. Recently, we constructed bacteriophage T4 Rnl1 expressing system in Streptococcus mutans, a crucial biofilm-forming and dental caries-causing oral pathogen. Here, we characterized the function of recombinant bacteriophage T4 Rnl1 in biofilm formation of S. mutans. The T4 Rnl1 mutant exhibited similar growth phenotype but resulted in a significant reduction of biofilm biomass compared to wild type strain and empty plasmid carrying strain. The abnormal biofilm of the T4 Rnl1 mutant harbored loose bacterial clusters with defective production and distribution of exopolysaccharides. Moreover, the expression of several biofilm formation-associated genes was dysregulated at mRNA level in the T4 Rnl1 mutant. These results reveal that the bacteriophage T4 Rnl1 exert antibiofilm activities against the cariogenic bacterium S. mutans, which impacts the spatial organization of the exopolysaccharides and further impairs the three-dimensional biofilm architecture. These findings implicate that manipulation of bacteriophage T4 Rnl1, a biological tool used for RNA ligation, will provide a promising approach to cariogenic biofilm control.

摘要

噬菌体T4 RNA连接酶1（T4 Rnl1）可以在许多细菌中稳定表达，并且据报道会影响宿主细菌的生物活性。最近，我们在变形链球菌中构建了噬菌体T4 Rnl1表达系统，变形链球菌是一种重要的生物膜形成和引起龋齿的口腔病原体。在这里，我们表征了重组噬菌体T4 Rnl1在变形链球菌生物膜形成中的功能。与野生型菌株和携带空质粒的菌株相比，T4 Rnl1突变体表现出相似的生长表型，但导致生物膜生物量显着减少。T4 Rnl1突变体的异常生物膜带有疏松的细菌簇，胞外多糖的产生和分布有缺陷。此外，在T4 Rnl1突变体的mRNA水平上，几个生物膜形成相关基因的表达失调。这些结果表明，噬菌体T4 Rnl1对生龋细菌变形链球菌具有抗生物膜活性，这影响胞外多糖的空间组织，并进一步损害三维生物膜结构。这些发现暗示着对噬菌体T4 Rnl1（一种用于RNA连接的生物学工具）的操作将为控制致龋生物膜提供一种有前途的方法。