Species of the genus Streptomyces, which constitute the vast majority of taxa within the family Streptomycetaceae, are a predominant component of the microbial population in soils throughout the world and have been the subject of extensive isolation and screening efforts over the years because they are a major source of commercially and medically important secondary metabolites. Taxonomic characterization of Streptomyces strains has been a challenge due to the large number of described species, greater than any other microbial genus, resulting from academic and industrial activities. The methods used for characterization have evolved through several phases over the years from those based largely on morphological observations, to subsequent classifications based on numerical taxonomic analyses of standardized sets of phenotypic characters and, most recently, to the use of molecular phylogenetic analyses of gene sequences. The present phylogenetic study examines almost all described species (615 taxa) within the family Streptomycetaceae based on 16S rRNA gene sequences and illustrates the species diversity within this family, which is observed to contain 130 statistically supported clades, as well as many unsupported and single member clusters. Many of the observed clades are consistent with earlier morphological and numerical taxonomic studies, but it is apparent that insufficient variation is present in the 16S rRNA gene sequence within the species of this family to permit bootstrap-supported resolution of relationships between many of the individual clusters.

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1,1-diphenyl-2-picrylhydrazyl (DPPH) radical-scavenging activity of the 70% aqueous acetone extract from the seed coat of the brown soybean variety, Akita-Zairai, was investigated. The activity of the seed coat of Akita-Zairai was much higher than that of three other reddish-brown varieties, but lower than that of two black varieties, and was closely dependent on the content of phenolic compounds. In the LH20 column chromatography of Akita-Zairai, high DPPH radical-scavenging activities were detected in the fractions eluted with MeOH and 70% aqueous acetone. Proanthocyanidins were also detected in fractions showing high radical-scavenging activities. Matrix-assisted laser desorption/ionization-time-of-flight mass spectrometry analysis showed that the degree of polymerization (DP) of the procyanidins contained in the brown or black soybean seed coat was as high as DP30.

Our findings indicate that the clinicopathological characteristics of gastric cancers detected after H. pylori eradication are different from those of gastric cancers in patients with persistent H. pylori infection. H. pylori eradication may suppress intestinalization during the development of gastric cancer.