Dataset Information

Quantification of uncultured Ruminococcus obeum-like bacteria in human fecal samples by fluorescent in situ hybridization and flow cytometry using 16S rRNA-targeted probes.

ABSTRACT: A 16S rRNA-targeted probe was designed and validated in order to quantify the number of uncultured Ruminococcus obeum-like bacteria by fluorescent in situ hybridization (FISH). These bacteria have frequently been found in 16S ribosomal DNA clone libraries prepared from bacterial communities in the human intestine. Thirty-two reference strains from the human intestine, including a phylogenetically related strain and strains of some other Ruminococcus species, were used as negative controls and did not hybridize with the new probe. Microscopic and flow cytometric analyses revealed that a group of morphologically similar bacteria in feces did hybridize with this probe. Moreover, it was found that all hybridizing cells also hybridized with a probe specific for the Clostridium coccoides-Eubacterium rectale group, a group that includes the uncultured R. obeum-like bacteria. Quantification of the uncultured R. obeum-like bacteria and the C. coccoides-E. rectale group by flow cytometry and microscopy revealed that these groups comprised approximately 2.5 and 16% of the total community in fecal samples, respectively. The uncultured R. obeum-like bacteria comprise about 16% of the C. coccoides-E. rectale group. These results indicate that the uncultured R. obeum-like bacteria are numerically important in human feces. Statistical analysis revealed no significant difference between the microscopic and flow cytometric counts and the different feces sampling times, while a significant host-specific effect on the counts was observed. Our data demonstrate that the combination of FISH and flow cytometry is a useful approach for studying the ecology of uncultured bacteria in the human gastrointestinal tract.

SUBMITTER: Zoetendal EG

PROVIDER: S-EPMC124080 | biostudies-literature | 2002 Sep

REPOSITORIES: biostudies-literature

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Quantification of uncultured Ruminococcus obeum-like bacteria in human fecal samples by fluorescent in situ hybridization and flow cytometry using 16S rRNA-targeted probes.

Zoetendal Erwin G EG Ben-Amor Kaouther K Harmsen Hermie J M HJ Schut Frits F Akkermans Antoon D L AD de Vos Willem M WM

Applied and environmental microbiology 20020901 9

A 16S rRNA-targeted probe was designed and validated in order to quantify the number of uncultured Ruminococcus obeum-like bacteria by fluorescent in situ hybridization (FISH). These bacteria have frequently been found in 16S ribosomal DNA clone libraries prepared from bacterial communities in the human intestine. Thirty-two reference strains from the human intestine, including a phylogenetically related strain and strains of some other Ruminococcus species, were used as negative controls and di ...[more]

PMID: 12200269

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Project description:In situ identification of whole fixed bacterial cells by hybridization with fluorescently labeled, rRNA-targeted oligonucleotide probes is often limited by low signal intensities. In addition to an impermeability of the cell periphery and a low cellular rRNA content, the three-dimensional structure of the ribosome may hinder the access of oligonucleotides to their target sites. Until now, a systematic study on the accessibility of 16S rRNA target sites had not been done. Here, we report fluorescence intensities obtained with more than 200 oligonucleotide probes (mostly 18-mers) used with whole fixed cells of Escherichia coli DSM 30083(T). Two overlapping sets of adjacent oligonucleotides, 171 in total, were designed to cover the full length of the 16S rRNA. The two sets are shifted by 5 to 13 nucleotides. The probes were labeled with carboxyfluorescein, and signal intensities of hybridized cells were quantified by flow cytometry. Care was taken that the signal intensity of cells was dependent solely on the in situ accessibility of probe target sites. The brightest signal resulted from probe Eco1482, complementary to positions 1482 to 1499. With this probe, the fluorescence was 1.7 times brighter than that of the standard bacterial probe EUB338 and 44 times brighter than that of the worst probe, Eco468. The distribution of probe-conferred cell fluorescence in six arbitrarily set brightness classes (classes I to VI; 100 to 81%, 80 to 61%, 60 to 41%, 40 to 21%, 20 to 6%, and 5 to 0% of the brightness with Eco1482, respectively) was as follows: I, 4%; II, 14%; III, 21%; IV, 29%, V, 19%; and VI, 13%. A more detailed analysis of helices 6, 18, and 23 with additional probes demonstrated that a shift of the target region by only a few bases could result in a decline of cell fluorescence from >80 to <10%. Considering the high evolutionary conservation of 16S rRNA, the in situ accessibility map of E. coli should facilitate a more rational selection of probe target sites for other species as well.

Dataset Information

Quantification of uncultured Ruminococcus obeum-like bacteria in human fecal samples by fluorescent in situ hybridization and flow cytometry using 16S rRNA-targeted probes.

Publications

Quantification of uncultured Ruminococcus obeum-like bacteria in human fecal samples by fluorescent in situ hybridization and flow cytometry using 16S rRNA-targeted probes.

Similar Datasets

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