05) in solid culture condition (Table 4). The expression of several genes which including those for a levanase (PINA0149), an extracytoplasmic function (ECF)-subfamily sigma factor (putative σE: PINA0299), a putative lipoprotein (PINA1510), and a putative polysialic acid transport protein (KpsD, PINA1911) were protruded. Among hypothetical proteins, PINA1526 (putative CpxP) NF-��B inhibitor showed extremely high levels of transcription. Table 4 Genes showing at least four-fold higher expression levels

in biofilm-forming Prevotella intermedia strain 17 than those of strain 17 in planktonic condition Gene Fold change Annotation PIN0036 4.67 Hypothetical protein PINA0141 6.78 Lipoprotein, putative PINA0149 12.45 Levanase, ScrL PINA0150 6.76 Levanase, SacC PINA0151 4.71 Glucose-galactose transporter, putative PINA0152 4.80 Fructokinase PINA0194 4.02 Outer membrane protein selleck HDAC phosphorylation PINA0298 10.42 Hypothetical protein PINA0299 9.16 ECF-subfamily sigma factor (σE, putative) PINA0300 5.62 Hypothetical protein PINA0612 7.21 Hypothetical protein PINA0990 4.24 Fibronectin type III domain protein PINA1157 10.88 Hypothetical protein PINA1452 4.24 Ribose-5-phosphate isomerase B PINA1494 9.65 Hemin receptor, putative PINA1510 18.41 Lipoprotein, putative PINA1525 16.93 Hypothetical protein PINA1526 28.60 Hypothetical protein with LTXXQ motif (CpxP, putative) PINA1665 5.84 Hypothetical protein PINA1807 7.24 Cell surface protein PINA1833

4.16 AraC family transcriptional regulator PINA1911 10.24 Polysialic acid transport protein, KpsD PINA1931 4.06 Alkyl hydroperoxide reductase, subunit C, AhpC PINA2066 8.94 Dps protein PINA2119 4.99 Agmatinase, SpeC Discussion It is well known that bacteria assuming biofilm-forming

capaCity have enormous advantages in establishing persistent infections even though they appear to be innocuous in their planktonic State [18–20]. Exopolysaccharide (EPS) is one of the main constituents of the biofilm extracellular matrix [21], and recent investigations have revealed that each biofilm-forming bacterium produces distinctive EPS components e.g. alginate Ribonuclease T1 and/or Psl found in Pseudomonas aeruginosa [22], acidic polysaccharide of Burkholderia cepacia [23], collanic acid, poly-β-1,6-GlcNAc (PGA) or cellulose found in Escherichia coli [24–27], cellulose of Salmonella [24, 28], amorphous EPS containing N-acetylglucosamine (GlcNAc), D-mannose, 6-deoxy-D-galactose and D-galactose of Vibrio cholerae [29], polysaccharide intercellular adhesin (PIA) of Staphylococcus [30], and glucose and mannose rich components found in Bacillus subtilis biofilm [31]. In this study we found that P. intermedia strain 17 produced a large amount of EPS, with mannose constituting more than 80% of the polysaccharides. Among oral bacteria, the production of mannose-rich polysaccharide by Capnocytophaga ochracea has been reported [32]. This EPS provides a protection from attack by the human innate immune system [33].