Minimum Inhibitory Concentration (MIC) of 4 new-quinolone antibacterial reagents and 4 macrolide antibiotics against periodontopathic bacteria 21 species 24 strains of standard strains including oral related bacteria and clinical isolated (1993-1999) 20 strains of Porphyromonas gingivalis, 7 strains of Actinobacillus actinomycetemcomitans were determined. Minocycline HCl was used as the comparative reagent. Macrolide showed moderate antibacterial activity against standard strains of oral related bacteria except Fusobacterium nucleatum. New-quinolone showed excellent activity against Eikenella corrodens and Actinobacillus actinomycetemcomitans. Concerning to the clinical isolated strains, Clarithromycin effected P. gingivalis (MIC90 0.1 microgram/ml) and Levofloxacin and Ciprofloxacin showed high-potency antibacterial activity against clinical isolated Actinobacillus actinomycetemcomitans (MIC90 0.013-0.025 microgram/ml).

In the course of new antibiotics screening, a complex of new basic macrolide antibiotics collectively named YL-704 was isolated from the culture broth of a streptomycete designated MCRL 0388. This complex consisted of two major components designated YL-704 A1 and YL-704 B1 and eleven other minor components. The antibiotic YL-704 complex-producing strain was characterized by the formation of hygroscopic masses of smooth-walled spores on aerial mycelia and by the production of diffusible and substrate pigment behaving as a pH indicator in glycerol-asparagine agar, inorganic salts-starch agar and tyrosine agar media. Progeny of the type strain have been deposited in the collections of the Northern Regional Research Laboratory, Agricultural Research Service, U. S. Department of Agriculture, Peoria, Illinois, U. S. A. as NRRL 3761, and the Fermentation Research Institute Chiba, Japan, as FERM-P No. 289. In the course of selecting for mutant strains, a mutant (strain MCRL 0393) was obtained with ultra-violet irradiation. This mutant produced dark green diffusible pigment. In contrast to the wild-type strain, the pigment was not a pH indicator. The mutant strain did not form hygroscopic masses of spores on any agar medium. The present paper concerns taxonomic studies on strain MCRL 0388 and multant strain MCRL 0393. Based on the results, strain MCRL 0388 is considered as a new subspecies of Streptomyces platensis, and the name Streptomyces platensis subsp. malvinus FURUMAI and OKUDA subsp. nov. is proposed. The type strain is MCRL 0388 (NRRL 3761) by virtue of its being a single isolate. The fermentative production of antibiotic YL-704 complex also is dealt with in this paper. Isolation and characterization of the components of the complex will be reported in another papery. Characterizationof Strain MCRL 0388The media used for morphological, cultural and physiological studies were those described by SHIRLING and GOTTLIEB2), and WAKSMAN3) . Taxonomic studies were generally carried out according to procedures described for the International Streptomyces Project (ISP)2) . Color names

Fusobacterium nucleatum promotes dental biofilm formation, increases the prevalence of periodontal disease, and is associated with systemic diseases such as colorectal cancer. However, the relationships of F. nucleatum in saliva with periodontal status and the composition of the salivary microbiome are unclear. Therefore, we analyzed these relationships in saliva samples collected from 611 subjects in Japan. Salivary DNA was extracted and the oral microbiome was analyzed using next-generation sequencing of 16S rRNA. The relationship between F. nucleatum and the community periodontal index was evaluated to examine effects on periodontal status, and α- and β-diversity were analyzed in three groups classified by relative abundance of F. nucleatum. Spearman rank correlation tests were used to examine relationships between the relative abundance of F. nucleatum and oral bacteria. Subjects with high levels of F. nucleatum had a higher prevalence of periodontitis compared with those with lower levels. β-diversity also differed between these two groups. F. nucleatum showed significant correlations with several periodontopathogens, including the red complex, P. intermedia, F. alocis and Fretibacterium ssp.. These results suggest that the relative abundance of F. nucleatum in saliva is associated with periodontal status and the composition of the salivary microbiome, including the red complex and periodontopathogens.

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