Asaccharobacter celatus gen. nov., sp. nov., isolated from rat caecum

Abstract

An obligately anaerobic and equol-producing bacterium, designated strain do03 T , was isolated from the caecal content of a rat. Cells were Gram-positive, non-spore-forming rods. The results from a phylogenetic analysis based on 16S rRNA gene sequences showed that strain do03 T formed a separate line of descent in the phylogenetic cluster of the family Coriobacteriaceae. The strain was unable to metabolize glucose or other carbohydrates as sole carbon sources; growth was enhanced in the presence of arginine. The cell wall contained meso-diaminopimelic acid. The major fatty acid was C 18 : 1 cis9 (54.0 %). The strain had one unidentified predominant (91.9 %) quinone that was not menaquinone, methylmenaquinone, demethylmenaquinone, ubiquinone or rhodoquinone. The DNA G+C content was 63 mol%. The data presented in this work show that strain do03T differs from members of the related recognized genera Eggerthella and Denitrobacterium at both the phylogenetic and phenotypic level. Therefore, the strain constitutes a novel genus and species, for which the name Asaccharobacter celatus gen. nov., sp. nov. is proposed. The type strain of the type species is do03The family Coriobacteriaceae was proposed by Stackebrandt et al. (1997) Kageyama & Benno, 2000). A Gram-positive bacterium, designated strain do03 T , capable of converting daidzein to equol via dihydrodaidzein was isolated from the caecal content of a rat (Minamida et al., 2006a). The 16S rRNA gene sequence (1428 bp) of the novel strain showed highest similarity (99 %) with that of the human intestinal bacterium SNUJulong 732 (GenBank accession no. AY310748), which was capable of metabolizing dihydrodaidzein to S-equol (Wang et al., 2005). The levels of similarity with respect to members of the three recognized species of the genus Eggerthella, Eggerthella sinensis HKU14 T (AY321958), Eggerthella hongkongensis HKU10 T (AY288517) and Eggerthella lenta ATCC 25559 T (AF292375), were in the range of 93 to 94 %. On the basis of the phylogenetic analysis, strain do03T differed from members of the genus Eggerthella and belonged to a novel genus of the family Coriobacteriaceae (Minamida et al., 2006a). In this paper, we describe additional taxonomic characteristics of the novel strain in comparison with phylogenetically close genera, and classify it as a novel genus and species within the family Coriobacteriaceae.Cell morphology and size after anaerobic cultivation at 37 u C for 2 days in Gifu anaerobic medium (GAM) broth (Nissui) were examined using phase-contrast microscopy (Nikon). Gram-staining was performed with 3-day-old culture by using a neo-B&M kit (Wako). Colonial morphologies were viewed after cultivation on GAM agar at 37 u C for 2 days in an anaerobic chamber (N 2 /H 2 /CO 2 , 85 : 5 : 10; Coy Laboratory). Biochemical traits were determined using both conventional methods (Holdeman et al., 1977) and the API 50 CH system (bioMérieux). Enzyme activities were analysed with the API ZYM system (bioMérieux) using bacteria harvested from GAM broth supplemented with ...

Isolation of a Human Intestinal Bacterium Capable of Daidzein and Genistein Conversion

“…While formation of equol from daidzein via dihydrodaidzein is catalyzed by several bacterial species (16,17,20,21,40), the corresponding conversion of genistein to 5-hydroxy-equol has been demonstrated for only two strains, Mt1B8 and DZE (13,17). This may be due to the fact that genistein transformation has not been investigated.…”

“…Lower values of sequence identity were observed for strain HE8 and the equol-forming species Adlercreutzia equolifaciens (90.2%), Eggerthella sp. strain Julong 732 (89.9%) and strain DZE (87.6%) from human feces, Asaccharobacter celatus (90.1%) from rat cecum, and strain Mt1B8 from mouse intestine (88.8%), all of which affiliate within the Coriobacteriaceae (13,16,17,20,21,36). All of these bacterial strains produce equol from daidzein, with the exception of Eggerthella sp.…”

Biotransformation of (−)-Epigallocatechin and (−)-Gallocatechin by Intestinal Bacteria Involved in Isoflavone Metabolism

“…Adlercreutzia equolifaciens MT4s-5 was isolated from rat feces as reported in our previous paper. 5) Adlercreutzia equolifaciens JCM 14793, 7) Asaccharobacter celatus JCM 14811, 8,9) Slackia equolifaciens JCM 16059, 10,11) and Slackia isoflavoniconvertens JCM 16137 12) were purchased from Riken Bioresource Center (Ibaraki, Japan). All other chemicals were available products of analytical or HPLC grade.…”

“…In this report, we describe the abilities of several commercially available isoflavone-metabolizing bacteria [7][8][9][10][11][12] to degrade EGC and its isomer GC. Furthermore, we note the p-dehydroxylation abilities of EGC metabolites, 3 and 4 by these bacteria.…”

Biotransformation of Daidzein to Equol by Crude Enzyme fromAsaccharobacter celatusAHU1763 Required an Anaerobic Environment

“…celatus AHU1763 was isolated from rat cecal content by our lab. 19) Current evidence for the conversion of DAI to EQL in bacteria is unavailable. Our study is the first to determine the enzymatic reaction involved in the conversion reaction of DAI to EQL.…”