title: Axenic culture of a candidate division TM7 bacterium from the human oral cavity and biofilm interactions with other oral bacteria.
abstract: The diversity of bacterial species in the human oral cavity is well recognized, but a high proportion of them are presently uncultivable. Candidate division TM7 bacteria are almost always detected in metagenomic studies but have not yet been cultivated. In this paper, we identified candidate division TM7 bacterial phylotypes in mature plaque samples from around orthodontic bonds in subjects undergoing orthodontic treatment. Successive rounds of enrichment in laboratory media led to the isolation of a pure culture of one of these candidate division TM7 phylotypes. The bacteria formed filaments of 20 to 200 μm in length within agar plate colonies and in monospecies biofilms on salivary pellicle and exhibited some unusual morphological characteristics by transmission electron microscopy, including a trilaminated cell surface layer and dense cytoplasmic deposits. Proteomic analyses of cell wall protein extracts identified abundant polypeptides predicted from the TM7 partial genomic sequence. Pleiomorphic phenotypes were observed when the candidate division TM7 bacterium was grown in dual-species biofilms with representatives of six different oral bacterial genera. The TM7 bacterium formed long filaments in dual-species biofilm communities with Actinomyces oris or Fusobacterium nucleatum. However, the TM7 isolate grew as short rods or cocci in dual-species biofilms with Porphyromonas gingivalis, Prevotella intermedia, Parvimonas micra, or Streptococcus gordonii, forming notably robust biofilms with the latter two species. The ability to cultivate TM7 axenically should majorly advance understanding of the physiology, genetics, and virulence properties of this novel candidate division oral bacterium.
authors.affiliation: School of Oral and Dental Sciences, University of Bristol, Bristol, United Kingdom.
authors.forename: Valeria
authors.initials: V
authors.lastname: Soro
authors.affiliation: School of Oral and Dental Sciences, University of Bristol, Bristol, United Kingdom.
authors.forename: Lindsay C
authors.initials: LC
authors.lastname: Dutton
authors.affiliation: School of Oral and Dental Sciences, University of Bristol, Bristol, United Kingdom.
authors.forename: Susan V
authors.initials: SV
authors.lastname: Sprague
authors.affiliation: School of Oral and Dental Sciences, University of Bristol, Bristol, United Kingdom.
authors.forename: Angela H
authors.initials: AH
authors.lastname: Nobbs
authors.affiliation: School of Oral and Dental Sciences, University of Bristol, Bristol, United Kingdom.
authors.forename: Anthony J
authors.initials: AJ
authors.lastname: Ireland
authors.affiliation: School of Oral and Dental Sciences, University of Bristol, Bristol, United Kingdom.
authors.forename: Jonathan R
authors.initials: JR
authors.lastname: Sandy
authors.affiliation: School of Biochemistry, University of Bristol, Bristol, United Kingdom.
authors.forename: Mark A
authors.initials: MA
authors.lastname: Jepson
authors.affiliation: Bioimaging Centre, College of Life and Environmental Sciences, University of Exeter, Exeter, United Kingdom.
authors.forename: Massimo
authors.initials: M
authors.lastname: Micaroni
authors.affiliation: Bioimaging Centre, College of Life and Environmental Sciences, University of Exeter, Exeter, United Kingdom.
authors.forename: Peter R
authors.initials: PR
authors.lastname: Splatt
authors.affiliation: School of Oral and Dental Sciences, University of Bristol, Bristol, United Kingdom.
authors.forename: David
authors.initials: D
authors.lastname: Dymock
authors.affiliation: School of Oral and Dental Sciences, University of Bristol, Bristol, United Kingdom howard.jenkinson@bristol.ac.uk.
authors.forename: Howard F
authors.initials: HF
authors.lastname: Jenkinson
mesh_terms: D000190:Actinomyces / Q000254:growth & development / Q000502:physiology; D000293:Adolescent; D061245:Axenic Culture; D001419:Bacteria / Q000145:classification / Q000166:cytology* / Q000235:genetics* / Q000302:isolation & purification; D018441:Biofilms / Q000254:growth & development; D002648:Child; D058645:Denaturing Gradient Gel Electrophoresis; D016967:Fusobacterium nucleatum / Q000254:growth & development / Q000502:physiology; D006801:Humans; D008969:Molecular Sequence Data; D009055:Mouth / Q000382:microbiology*; D009967:Orthodontic Appliances / Q000382:microbiology; D010802:Phylogeny; D016966:Porphyromonas gingivalis / Q000254:growth & development / Q000502:physiology; D040901:Proteomics / Q000379:methods; D012336:RNA, Ribosomal, 16S; D054773:Streptococcus gordonii / Q000254:growth & development / Q000502:physiology
chemical_list: D012336:RNA, Ribosomal, 16S
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