, 1966; Watanabe & Snell, 1977; Yoshida et al., 2009; Sasaki-Imamura et al., 2010). These findings suggested that the affinity of P. intermedia TnaA to l-tryptophan is largely similar to that of other TnaA proteins. In contrast, the kcat and kcat/Km values of selleck chemical P. intermedia TnaA (0.45 s−1 and 1.96 mM s−1, respectively) were less than those for E. coli (6.8 s−1 and 30 mM s−1, respectively), P. gingivalis (1.4 s−1 and 6.9 mM s−1, respectively), and F. nucleatum (0.7 s−1 and 2.8 mM s−1, respectively) TnaA, which suggested that the capacity of TnaA from P. intermedia to produce indole l-tryptophan was not as high as in the case of other bacteria. The kcat/Km value of

P. intermedia TnaA for l-tryptophan learn more was much higher than for S-methyl-l-cysteine and S-ethyl-l-cysteine. The enzyme did not exhibit detectable elimination activity with l-alanine, l-serine, or l-cysteine, the latter two of which are degraded by TnaA from E. coli (Morino & Snell, 1970) and Proteus vulugalis (Zakomirdina et al., 2002). The substrate specificity of TnaA from P. intermedia was similar to other oral periodontophathogenic bacteria such as P. gingivalis (Yoshida et al., 2009)

and F. nucleatum (Sasaki-Imamura et al., 2010). Using a modified assay with Kovac’s reagent, which measures the concentration of indole in bacterial culture media, we evaluated the indole-producing capacity of 22 species of Prevotella isolated from craniofacial regions (Table 1). Indole was detected in the culture supernatants of six species (P. intermedia ATCC 25611, Prevotella aurantiaca JCM 15754, Prevotella falsenii JCM 15124, Prevotella micans JCM 16134, Prevotella nigrescens JCM 6322, and Prevotella pallens ATCC 700821), albeit at concentrations (0.05–0.1 mM) that were lower than in cultures of P. gingivalis (0.17 mM) and F. nucleatum (0.22 mM). No detectable levels of indole were observed in the culture supernatants of the remaining 16 Prevotella species. These findings were in agreement with previous reports (Dellinger & Moore, 1986; Alauzet et al., 2010). The presence of the tnaA gene in the 22 strains of Prevotella species was also investigated by Southern hybridization

(Fig. 3). Specific signals for P. intermedia ATCC 25611 tnaA were detected in P. gingivalis and the six Prevotella species that were positive for indole in the culture supernatants Dapagliflozin (Table 1). As a control, there were no specific signals for tnaA from F. nucleatum ATCC 25586 in any of the tested bacteria, with the exception of the positive control, F. nucleatum. These findings suggested that the tnaA genes from at least six Prevotella species (P. intermedia ATCC 25611, P. aurantiaca JCM 15754, P. falsenii JCM 15124, P. micans JCM 16134, P. nigrescens JCM 6322, and P. pallens ATCC 700821) might be genetically closer to P. gingivalis than F. nucleatum. Our results indicated that 16 of 22 Prevotella species tested did not produce indole.