Gene expression of Porphyromonas gingivalis biofilm

Objectives: Porphyromonas gingivalis is one of the major aetiological agents involved in advance adult periodontitis. An important factor of the organism on the disease is thought to form biofilm in the oral cavity. But, the characteristics of P. gingivalis biofilm are not fully understood. It is supposed that biofilm cells posses distinct characteristics from planktonic cells. The aim of this study is to investigate the difference of gene expression between biolfilm cells and planktonic cells of P. gingivalis. Methods: P. gingivalis np11 was grown anaerobically at 37 C with Tryptic soy broth supplemented with Yeast extract, hemin, and menadione in 96 well plate. Planktonic cells and biofilm cells of P. gingivalis were obtained from supernatant and adhered cells in the 96 well plate. For the DNA array, the RNA of the both cells were extracted from with the RNeasy minikit. cDNA was generated using random primers for reverse transcription. The DNA array which contained 1,909 of the P. gingivalis W83 gene were performed at GeneFrontier with NimbleGen system. Results: The results indicated that upregulated 32 genes in biofilm cells contained ORFs for 4 ABC transporters, efflux transporter, thioredoxin family protein, Tet R, luxR, sensor histidine kinase and so on, and downregulated 42 genes were ORFs for heat shock protein 90, OxyR, outer membrane efflux protein, RND and so on. According to the another reports indicating that ABC transporters are associated with the transport of many substance, cell to cell interaction and biofilm development, ABC transporters of P. gingivalis are also important for biofilm formation. Conclusion: This study suggests that the protein for transport system may be important roles for biofilm development of P. gingivlais.