title: Treponema denticola biofilm-induced expression of a bacteriophage, toxin-antitoxin systems and transposases.
abstract: 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.
authors.affiliation: Cooperative Research Centre for Oral Health Science, Melbourne Dental School, Bio21 Institute, The University of Melbourne, Australia.
authors.forename: Helen L
authors.initials: HL
authors.lastname: Mitchell
authors.affiliation: Cooperative Research Centre for Oral Health Science, Melbourne Dental School, Bio21 Institute, The University of Melbourne, Australia.
authors.forename: Stuart G
authors.initials: SG
authors.lastname: Dashper
authors.affiliation: Cooperative Research Centre for Oral Health Science, Melbourne Dental School, Bio21 Institute, The University of Melbourne, Australia.
authors.forename: Deanne V
authors.initials: DV
authors.lastname: Catmull
authors.affiliation: Cooperative Research Centre for Oral Health Science, Melbourne Dental School, Bio21 Institute, The University of Melbourne, Australia.
authors.forename: Rita A
authors.initials: RA
authors.lastname: Paolini
authors.affiliation: Cooperative Research Centre for Oral Health Science, Melbourne Dental School, Bio21 Institute, The University of Melbourne, Australia.
authors.forename: Steven M
authors.initials: SM
authors.lastname: Cleal
authors.affiliation: Cooperative Research Centre for Oral Health Science, Melbourne Dental School, Bio21 Institute, The University of Melbourne, Australia.
authors.forename: Nada
authors.initials: N
authors.lastname: Slakeski
authors.affiliation: Cooperative Research Centre for Oral Health Science, Melbourne Dental School, Bio21 Institute, The University of Melbourne, Australia.
authors.forename: Kheng H
authors.initials: KH
authors.lastname: Tan
authors.affiliation: Cooperative Research Centre for Oral Health Science, Melbourne Dental School, Bio21 Institute, The University of Melbourne, Australia.
authors.forename: Eric C
authors.initials: EC
authors.lastname: Reynolds
mesh_terms: D000992:Antitoxins / Q000235:genetics / Q000378:metabolism*; D018441:Biofilms; D019295:Computational Biology; D004269:DNA, Bacterial / Q000235:genetics; D004279:DNA, Viral / Q000235:genetics; D020869:Gene Expression Profiling; D015964:Gene Expression Regulation, Bacterial; D016680:Genome, Bacterial; D016679:Genome, Viral; D008855:Microscopy, Electron, Scanning; D046529:Microscopy, Electron, Transmission; D020411:Oligonucleotide Array Sequence Analysis; D039002:Prophages / Q000235:genetics / Q000302:isolation & purification* / Q000648:ultrastructure; D020543:Proteome / Q000378:metabolism; D012329:RNA, Bacterial / Q000235:genetics; D019895:Transposases / Q000235:genetics / Q000378:metabolism*; D048373:Treponema denticola / Q000201:enzymology / Q000235:genetics* / Q000821:virology
chemical_list: D000992:Antitoxins; D004269:DNA, Bacterial; D004279:DNA, Viral; D020543:Proteome; D012329:RNA, Bacterial; D019895:Transposases