title: Proteomics of Porphyromonas gingivalis within a model oral microbial community.
abstract: BACKGROUND
  Porphyromonas gingivalis is a periodontal pathogen that resides in a complex multispecies microbial biofilm community known as dental plaque. Confocal laser scanning microscopy showed that P. gingivalis can assemble into communities in vitro with Streptococcus gordonii and Fusobacterium nucleatum, common constituents of dental plaque. Whole cell quantitative proteomics, along with mutant construction and analysis, were conducted to investigate how P. gingivalis adapts to this three species community.
  
  
  RESULTS
  1156 P. gingivalis proteins were detected qualitatively during comparison of the three species model community with P. gingivalis incubated alone under the same conditions. Integration of spectral counting and summed signal intensity analyses of the dataset showed that 403 proteins were down-regulated and 89 proteins up-regulated. The proteomics results were inspected manually and an ontology analysis conducted using DAVID. Significant decreases were seen in proteins involved in cell shape and the formation of the cell envelope, as well as thiamine, cobalamin, and pyrimidine synthesis and DNA repair. An overall increase was seen in proteins involved in protein synthesis. HmuR, a TonB dependent outer membrane receptor, was up-regulated in the community and an hmuR deficient mutant was deficient in three species community formation, but was unimpaired in its ability to form mono- or dual-species biofilms.
  
  
  CONCLUSIONS
  Collectively, these results indicate that P. gingivalis can assemble into a heterotypic community with F. nucleatum and S. gordonii, and that a community lifestyle provides physiologic support for P. gingivalis. Proteins such as HmuR, that are up-regulated, can be necessary for community structure.
authors.affiliation: Department of Preventive Dentistry, Osaka University Graduate School of Dentistry, Osaka, Japan. kuboniwa@dent.osaka-u.ac.jp
authors.forename: Masae
authors.initials: M
authors.lastname: Kuboniwa
authors.forename: Erik L
authors.initials: EL
authors.lastname: Hendrickson
authors.forename: Qiangwei
authors.initials: Q
authors.lastname: Xia
authors.forename: Tiansong
authors.initials: T
authors.lastname: Wang
authors.forename: Hua
authors.initials: H
authors.lastname: Xie
authors.forename: Murray
authors.initials: M
authors.lastname: Hackett
authors.forename: Richard J
authors.initials: RJ
authors.lastname: Lamont
mesh_terms: D001425:Bacterial Outer Membrane Proteins / Q000235:genetics / Q000378:metabolism; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism; D018441:Biofilms / Q000254:growth & development*; D015536:Down-Regulation; D016967:Fusobacterium nucleatum / Q000502:physiology; D006801:Humans; D018613:Microscopy, Confocal; D009055:Mouth / Q000382:microbiology*; D009154:Mutation; D016966:Porphyromonas gingivalis / Q000235:genetics / Q000502:physiology*; D040901:Proteomics / Q000379:methods*; D054773:Streptococcus gordonii / Q000502:physiology; D015854:Up-Regulation
chemical_list: D001425:Bacterial Outer Membrane Proteins; D001426:Bacterial Proteins