7 Glucose 53.5 Galactose 29.2 Arabinose 17.3 Xylose 5.8 Rhamnose 2.8 Ribose 2.2 Figure 4 Transmission electron microscopy of negatively

stained exopolysaccharides isolated from Prevotella intermedia check details strains 17 culture supernatants. Note the fine fibrous structures that are formed in bundles. Bar = 500 nm. Gene expression profiles of P. intermedia strains 17 and 17-2 To see what kind of gene expression events induce phenotypic differences on P. intermedia, we compared gene expression patterns between strains 17 and 17-2, the respective viscous material producing and non-producing strains using microarray analysis. To determine the appropriate time point for isolating total RNA, we first observed the morphological changes of cell surface structures in each LY2874455 chemical structure strain along with the bacterial growth. In general, the growth of strain 17-2 was faster than that of strain 17, entering into an exponential phase at around 12 h and reaching the plateau in 24 h (Fig. 5A, open rhombus). Strain 17-2 did not show the presence of cell-associated fibrous materials at HMPL-504 any stage of the growth cycle (Fig. 5C). By contrast, strain 17 showed a slower growth rate (Fig. 5A, hatched square)

with a longer exponential growth phase. Morphological observation of cultures at different stages of growth revealed that strain 17 exhibited cell surface-associated meshwork-like structures at 12 h and the structures became denser with time (Fig 5B). From these preliminary data, 12 h-old cultures of strains 17 and 17-2 were chosen for Rapamycin purchase a comparison of gene expression patterns. When the microarray expression data for strains 17 and 17-2 were compared, a total of 11 genes were up-regulated by at least two-fold with statistic significance (p < 0.05) in biofilm-forming P. intermedia strain

17 (Table 3). The expression data demonstrated that several heat shock protein (HSP) genes, such as dnaJ, dnaK, groES, groEL and clpB were up-regulated in strain 17 (Table 3). We also identified two genes down-regulated at least two-fold in strain 17 (PINA2115: hypothetical protein; PINA2117: sterol-regulatory element binding protein (SREBP) site 2 protease family). The original raw data files have been deposited in Center for Information Biology gene Expression database (CIBEX; Mishima, Japan; CIBEX accession: CBX27) [17]. Table 3 Genes showing at least two-fold higher expression levels in biofilm-forming Prevotella intermedia strain 17 than those of non-forming variant strain 17-2 Gene Fold change Annotation PIN0258 2.63 Hypothetical protein PIN0281 3.42 Heat shock protein 90, HtpG PINA0419 2.17 Hypothetical protein PINA0775 2.47 Patatin-like phospholipase family protein PINA1058 2.28 DnaK protein PINA1693 2.09 Folylpolyglutamate synthase, FolC PINA1756 2.35 Heat shock protein, DnaJ PINA1757 2.31 Hypothetical protein PINA1797 2.33 Chaperonin, 60 kDa, GroEL PINA1798 2.39 Chaperonin, 10 kDa, GroES PINA2006 2.17 ClpB protein Figure 5 Growth of P.