A Linear Plasmid-Like Prophage of Actinomyces odontolyticus Promotes Biofilm Assembly

Abstract

The human oral cavity is home to a large number of bacteria and bacteriophages (phages). However, the biology of oral phages as members of the human microbiome is not well understood. Recently, we isolated subsp. strain XH001 from the human oral cavity, and genomic analysis revealed the presence of an intact prophage named xhp1. Here, we demonstrated that xhp1 is a linear plasmid-like prophage, which is a newly identified phage of The prophage xhp1 genome is a 35-kb linear double-stranded DNA with 10-bp single-stranded, 3' cohesive ends. xhp1 exists extrachromosomally, with an estimated copy number of 5. Annotation of xhp1 revealed 54 open reading frames, while phylogenetic analysis suggests that it has limited similarity with other phages. xhp1 phage particles can be induced by mitomycin C and belong to the family, according to transmission electron microscopic examination. The released xhp1 particles can reinfect the xhp1-cured XH001 strain and result in tiny blurry plaques. Moreover, xhp1 promotes XH001 biofilm formation through spontaneous induction and the release of host extracellular DNA (eDNA). In conclusion, we identified a linear plasmid-like prophage of , which enhances bacterial host biofilm assembly and could be beneficial to the host for its persistence in the oral cavity. The biology of phages as members of the human oral microbiome is understudied. Here, we report the characterization of xhp1, a novel linear plasmid-like prophage identified from a human oral isolate, subsp. strain XH001. xhp1 can be induced and reinfect xhp1-cured XH001. The spontaneous induction of xhp1 leads to the lysis of a subpopulation of bacterial hosts and the release of eDNA that promotes biofilm assembly, thus potentially contributing to the persistence of within the oral cavity.

Salivary microbiome in patients undergoing hemodialysis and its associations with the duration of the dialysis

“…Actinomyces odontolyticus, core microbiome of the healthy community with relative abundance > 1%, is a gram-positive facultative aerobic bacterium, which decreased significantly in the HD community. Previous studies have reported that A. odontolyticus was the host of the candidate phylum Saccharibacteria, being associated with human inflammatory mucosal diseases, thereby killed by a parasitic phase [51,52]. By contrast, Porphyromonas gingivalis, core microbiome of the HD community with relative abundance > 1%, is a convincedly proposed keystone bacterium in the genesis and development of periodontitis, which was at significantly higher level in the HD group.…”

Rumen Virus Populations: Technological Advances Enhancing Current Understanding

“…To add to this complexity, viruses has been shown to promote biofilm formation for a number of bacterial genera, such as Bacillus and Actinomyces, via spontaneous induction of prophage and release of extracellular DNA, which contributes to the extracellular matrix (Schuch and Fischetti, 2009;Carrolo et al, 2010;Wang et al, 2010;Shen et al, 2018). Davies et al (2016) have also demonstrated that temperate viruses can drive the evolution and adaptation of cells within a biofilm through insertional inactivation of genes.…”

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“…These findings suggest that temperate phages play some role in bacterial biofilms. Laboratory-scale studies with single species biofilms suggests that prophage induction is an important process in the release of extracellular DNA, a necessary component of the biofilm matrix [ [54] , [55] , [56] ]. Thus, prophage induction may likewise be an important mechanism for building the biofilm matrix in mixed species lotic biofilms.…”