Nine Campylobacter-like strains were isolated from human gingival crevices and characterized. These strains were gram-negative, straight rods that were motile by means of multiple unipolar flagella. They were asaccharolytic and preferred an anaerobic atmosphere rather than a microaerophilic atmosphere for growth, and their growth was stimulated by formate and fumarate. These strains were biochemically similar to Campylobacter curvus and Campylobacter rectus, but were clearly distinguishable from these organisms by the number of flagella (two to five flagella at one end of the cell), by being catalase positive, by their whole-cell protein profiles, by their Western blot (immunoblot) patterns, and on the basis of DNA-DNA homology data. They could also be differentiated from the other species of the genus CampyZobacter. The nine Campylohcterlike strains were compared with two strains (FDC 286 and VPI 10279) representing a previously described but unnamed WolinelZu sp, The nine isolates and strains FDC 286 and VPI 10279 were found to be members of a single species. The 16s rRNA sequences of two strains of the newly identified species were compared with the rRNA sequences of 21 reference Campylobacter, Wolinelh, and Helicobacter species in order to generate a phylogenetic tree. We propose the name Campylobacter showae for the newly identified strains; strain SU A4 (= ATCC 51146) is the type strain of this new species.Previously, we isolated several Wolinella-like strains from human subgingival dental plaque (16) and subsequently proposed Wolinella cuwa subsp. intemedius as a new subspecies for two of the isolates (SU A4T [T = type strain] and SU A5) (4). These organisms could be differentiated at least at the subspecies level by morphological, biochemical, antigenic, and DNA-DNA homology methods from the other human oral Wolinella species, W. cuwa and Wolinella recta, which recently have been transferred to the genus Campylobacter as Campylobacter cuwus and Campylobacter rectus, respectively, by Vandamme et al. (24,25). In order to more fully describe the status of a new species in the genus Campylobacter, seven additional strains were isolated; thus, a total of nine strains, including SU A4T and SU A5, were characterized. These nine isolates were compared with Wolinella sp. strains FDC 286 (22) and VPI 10279 (14) and strains of other Campylobacter species (19,20,24,25). A 16s rRNA sequence analysis was used to determine the phylogenetic position of strains SU A4T and VPI 10279. The nine isolates and strains FDC 286 and VPI 10279 are members of a new species, for which we propose the name Campylobacter showae . MATERIALS AND METHODSBacterial strains and characterization. The sources and accession numbers of the isolates and reference strains examined in this study are shown in Table 1. The nine Camwlobacter-like strains were isolated from the dental plaque of gingival crevices of nine apparently healthy adults on plates containing modified CBRCA (26), which is a selective medium for Campylobacter, Fusobactenum, Bacte...

We found and sequenced intervening sequences (IVSs) in the PCR-amplicons of 16S rRNA genes of 3 strains of Campylobacter rectus, 2 strains of C. curvus and 2 strains of C. sputorum. The lengths of the IVSs were 140 to 233 bp. The IVSs of C. rectus were identical and had a sequence homology of 55 to 79% against those of C. curvus and C. helveticus. The IVSs of C. sputorum were 97.9-100% homologous but poorly homologous to the other IVSs. In spite of the diversities of the lengths and the nucleotide sequences, all of the IVSs were located at the same position in the 16S rRNA genes.

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The extracellular levanase of Actinomyces viscosus ATCC 19246 was purified about 3,701-fold in 11% yield from the bacterial culture supernatant by means of ammonium sulfate precipitation, followed by DE52 column chromatography, Sephadex G-100 gel filtration, hydroxylapatite column chromatography, and Bio-Gel A 1.5m gel filtration. The molecular weight of the enzyme was estimated to be 89,000 by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The enzyme was optimally reactive at pH 6.0 and at 45 degrees C. The activity was inhibited by MnCl2, BaCl2, FeCl3, ZnCl2, HgCl2, and EDTA at a final concentration of 1 mM. The inhibition by EDTA was recovered by adding CaCl2 or MgCl2. The enzyme specifically hydrolyzed levan, but not sucrose, raffinose, melezitose, inulin, and dextran. These results indicate that the purified enzyme is specific for fructan (i.e., levan), which mainly consists of beta-(2,6) linkages.

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