Isolation and characterization of thirteen intestinal microorganisms capable of 7 alpha-dehydroxylating bile acids

Hirano, Shuichiro; Nakama, R; Tamaki, Masahiko; Masuda, Noriyuki; Oda, Hiroshi

doi:10.1128/aem.41.3.737-745.1981

Cited by 106 publications

(66 citation statements)

References 27 publications

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“…The samples were homogenized in 100 mM HEPES buffer (pH 7.5) and appropriate dilutions of the fecal suspensions were plated on a nutritionally poor agar medium, 1/4 × Gifu anaerobic medium (GAM) (1/4GAM) (Nissui Pharmaceutical Co. Ltd, Tokyo, Japan), containing 15 g L −1 agar to avoid overlapping of bacterial colonies by limiting the growth of rapidly growing bacterial species, thereby facilitating the isolation of slow growers. After 2–7 days of culture, the colonies on the plates were picked and cultured either in 200 μL of GAM, liquid casein yeast (LCY), or peptone–yeast extract (PY) broth containing 0.1 mM CA or CDCA in 96‐well microtiter plates for 48 h. The compositions of LCY and PY broth were described by Lepercq et al (2004) and in Hirano et al (1981), respectively. The bile acid conversion activity of each isolate was detected by thin‐layer chromatography (TLC) as described below; all positive cultures that gave disappearance of substrate spot and/or appearance of new spot(s) corresponding to possible reaction products were tested for reproducibility.…”

Section: Methodsmentioning

confidence: 99%

Conversion of cholic acid and chenodeoxycholic acid into their 7-oxo derivatives byBacteroides intestinalisAM-1 isolated from human feces

Fukiya¹,

Arata²,

Kawashima³

et al. 2009

FEMS Microbiology Letters

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Secondary bile acid-producing bacteria were isolated from human feces to improve our appreciation of the functional diversity and redundancy of the intestinal microbiota. In total, 619 bacterial colonies were isolated using a nutrient-poor agar medium and the level of secondary bile acid formation was examined in each by a liquid culture, followed by thin-layer chromatography. Of five strains analyzed by 16S rRNA gene sequencing and biochemical testing, one was identified as Bacteroides intestinalis AM-1, which was not previously recognized as a secondary bile-acid producer. GC-MS revealed that B. intestinalis AM-1 converts cholic acid (CA) and chenodeoxycholic acid into their 7-oxo derivatives, 7-oxo-deoxycholic acid (7-oxo-DCA) and 7-oxo-lithocholic acid, respectively. Thus, B. intestinalis AM-1 possesses 7alpha-hydroxysteroid dehydrogenase (7alpha-HSDH) activity. In liquid culture, B. intestinalis AM-1 showed a relatively higher productivity of 7-oxo-DCA than Escherichia coli HB101 and Bacteroides fragilis JCM11019(T), which are known to possess 7alpha-HSDH activity. The level of 7alpha-HSDH activity was higher in B. intestinalis AM-1 than in the other two strains under the conditions tested. The 7alpha-HSDH activity in each of the three strains is not induced by CA; instead, it is regulated in a growth phase-dependent manner.

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Section: Methodsmentioning

confidence: 99%

Conversion of cholic acid and chenodeoxycholic acid into their 7-oxo derivatives byBacteroides intestinalisAM-1 isolated from human feces

Fukiya¹,

Arata²,

Kawashima³

et al. 2009

FEMS Microbiology Letters

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“…Which bacteria in human intestinal microflora correspond to the present clostridia in rats is not yet known but some species of human intestinal bacteria have been reported to have 7α-dehydroxylation activity (4)(5)(6)(7)(8)(9)(10)(11), although the counts of 7α-dehydroxylating positive bacteria were as low as 10 5 -10 6 counts per g wet weight feces. Stellwag and Hylemon (7) reported that the 7α-dehydroxylation activity of mixed fecal bacteria was 0.06-0.012 µmol/h·mg protein for cholic acid in an in vitro system.…”

Section: Discussionmentioning

confidence: 99%

“…Deconjugation activity is found in many species of intestinal bacteria (3) but those possessing 7α-dehydroxylation activity are limited. 7α-Dehydroxylating activity is found in Clostridium (4-7), Bacteroides (8), Lactobacillus (9), Eubacterium (4,5,10,11) and in as yet unclassified intestinal bacteria (4,5). The population of these 7α-dehydroxylating bacteria is not large, and their counts are only 10 5 -10 6 per g wet feces, while the counts of dominant intestinal bacteria possessing no 7α-dehydroxylation activity (12) are around 10 11 -10 12 per g wet feces.…”

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confidence: 99%

Transformation of bile acids and sterols by clostridia (fusiform bacteria) in Wistar rats

Uchida¹,

Satoh²,

Narushima³

et al. 1999

Lipids

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The effects on bile acid and sterol transformation of clostridia (fusiform bacteria), the dominant intestinal bacteria in rodents (ca. 10(10) counts per g wet feces) were examined in Wistar rats. After inoculation of clostridia into germ-free rats and into rats previously inoculated solely with Escherichia coli, most of the endogenous bile acids were deconjugated, and cholic acid and chenodeoxycholic acid were 7alpha-dehydroxylated to deoxycholic acid and lithocholic acid, respectively. Tauro-beta-muricholic acid, another major bile acid in rats, was deconjugated, but only part of it (ca. 30%) was transformed into hyodeoxycholic acid. Cholesterol and sitosterol were also reduced to coprostanol and sitostanol, respectively. Escherichia coli transformed neither bile acids nor sterols. These data suggest that clostridia play an important role in the formation of secondary bile acids and coprostanol in rats.

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“…casei 1001 were obtained from the Yakult Central Institute (Tokyo). Strain HD-17 is an unusually coiled anaerobic, gram-positive, nonsporeforming rod isolated from human feces (2). The five strains of Peptostreptococcus productus, the two strains of Eubacterium lentum and the five strains of an E. lentum-like organism were isolated from human feces.…”

Section: Methodsmentioning

confidence: 99%

Detection of Fine Spiral Structures (Spirosomes) by Weak Sonication in Some Bacterial Strains

Matayoshi

Oda

1985

Microbiology and Immunology

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Fine spiral structures (spirosomes) were observed in cell suspensions of five species of bacteria just after weak sonication. The structure is morphologically indistinguishable from the spirosome reported for Lactobacillus species. The molecular weight of the protein of the spirosomes from nine strains was about 94, 000 to 95, 000 as determined by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The difference in the molecular weight among these spirosomes was not very great, but there were slight differences among the strains from which the spirosomes were derived.Holt and Canale-Parola (3) observed a helical array structure on the protoplasmic cylinder of Spirochaeta stenostrepta, and separated the individual helices or segments of helices from the cell by ballistic disintegration. Ueda and Takagi (11) found similar spiral structures in mitomycin-induced lysates of Clostridium botulinu m type B. Kawata et al (6) found similar particles in the mesosomal fraction obtained from protoplasts of Lactobacillus fermenti and Lactobacillus casei by osmotic disruption and named the particle "spirosome." Since then, spirosomes or similar particles have been observed in both gram-positive and gram-negative bacteria (4, 5, 7, 9). However their true origin and function are still obscure.During our investigation of the surface ultrastructure of some anaerobic bacteria, we observed many spiral structures in the bacterial cell suspension just after weak ultrasonic treatment. The spiral structures are morphologically indistinguishable from the spirosomes reported for Lactobacillus species (6). In this paper, we describe the spirosomes revealed by weak sonication in various species of bacteria. MATERIALS AND METHODSOrganisms and cultivation. The 47 strains of bacteria used in this study are listed in Table 1. L. fermentum NCTC7230 and L. casei var. casei 1001 were obtained from the Yakult Central Institute (Tokyo). Strain HD-17 is an unusually coiled anaerobic, gram-positive, nonsporeforming rod isolated from human feces (2). The five strains of Peptostreptococcus productus, the two strains of Eubacterium lentum and the 1 3

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Isolation and characterization of thirteen intestinal microorganisms capable of 7 alpha-dehydroxylating bile acids

Cited by 106 publications

References 27 publications

Conversion of cholic acid and chenodeoxycholic acid into their 7-oxo derivatives byBacteroides intestinalisAM-1 isolated from human feces

Conversion of cholic acid and chenodeoxycholic acid into their 7-oxo derivatives byBacteroides intestinalisAM-1 isolated from human feces

Transformation of bile acids and sterols by clostridia (fusiform bacteria) in Wistar rats

Detection of Fine Spiral Structures (Spirosomes) by Weak Sonication in Some Bacterial Strains

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