In addition, the capacity to remain functional in the suboptimal pH environment may also be attributed to the altered concentration of stress proteins. The significant increased abundance of adhesin FomA at pH 8.2 may be associated with the surface change that promotes biofilm formation. The elongation observed
in bacterial cells cultured at pH 8.2 may be due to a decrease abundance of RND transporters that play a role in cells. The altered intracellular concentration three hypothetical proteins reported may be important for coping with pH stress but their roles are yet to be fully investigated. Significant changes in protein concentration were validated using a variety of techniques and generally indicated the high reliability of proteomic data. The shift to biofilm find more growth and the changed protein expression reflected mechanisms that likely enable F. nucleatum to adapt successfully and compete in its natural habitat HTS assay in the oral cavity. It has been suggested that interactions between oral bacteria present in dental plaque result in many new physiological functions which cannot be observed in an individual component system [77]. Kuboniwa and colleagues (2009) examined the protein expression
of P. gingivalis growing in a three-species system containing the pioneer plaque species Streptococcus gordonii and F. nucleatum revealing the protective mechanisms that may exist within multi-species communities [78]. The development of multi-species biofilm systems in the future may be used to increase knowledge of the gene and protein expression of F. nucleatum. Acknowledgements This work
was supported by The Australian Dental Research Foundation. J. Chew was supported by Adelaide Scholarships International. We thank Tracy Fitzsimmons, Krzysztof Mrozik, Victor Marino and staff at The Adelaide Proteomics Centre for excellent technical assistance. Electronic supplementary material Additional file 1: Table S1. Summary of 2DE conditions mafosfamide used for separation of cytoplasmic and membrane proteins. (DOC 32 KB) Additional file 2: Table S2. Designed primers used for qRT-PCR. (DOC 36 KB) References 1. Ron EZ: Bacterial stress response. In The prokaryotes. 3rd edition. Edited by: Dworkin M, Falkow S, Rosenberg E, Schleifer KH, Stackebrandt E. Springer, New York; 2006:1012–1027.CrossRef 2. Bolstad AI, Jensen HB, Bakken V: Taxonomy, biology, and periodontal aspects of fusobacterium nucleatum. Clin Microbiol Rev 1996,9(1):55–71.PubMed 3. Signat B, Roques C, Poulet P, Duffaut D: Role of fusobacterium nucleatum in periodontal health and disease. Curr Issues Mol Biol 2011, 13:25–36.PubMed 4. Socransky S, Haffajee A, Cugini M, Smith C, Kent R: Microbial complexes in subgingival plaque. J Clin Periodontol 1998,25(2):134–144.PubMedCrossRef 5. Karpathy SE, Qin X, Gioia J, Jiang H, Liu Y, Petrosino JF, Yerrapragada S, Fox GE, Haake SK, Weinstock GM, et al.