title: The active human gut microbiota differs from the total microbiota.
abstract: The human gut microbiota is considered one of the most fascinating reservoirs of microbial diversity hosting between 400 to 1000 bacterial species distributed among nine phyla with Firmicutes, Bacteroidetes and Actinobacteria representing around 75% of the diversity. One of the most intriguing issues relates to understanding which microbial groups are active players in the maintenance of the microbiota homeostasis.Here, we describe the diversity of active microbial fractions compared with the whole community from raw human fecal samples. We studied four healthy volunteers by 16S rDNA gene pyrosequencing. The fractions were obtained by cell sorting based on bacterial RNA concentration. Bacterial families were observed to appear or disappear on applying a cell sorting method in which flow cytometry was used to evaluate the active cells by pyronin-Y staining of RNA. This method was able to detect active bacteria, indicating that the active players differed from that observed in raw fecal material. Generally, observations showed that in the active fractions, the number of reads related to Bacteroidetes decreased whereas several families from Clostridiales (Firmicutes) were more highly represented. Moreover, a huge number of families appeared as part of the active fraction when cell sorting was applied, indicating reads that are simply statistically hidden by the total reads.
authors.affiliation: Joint Unit of Research in Genomics and Health, Centre for Public Health Research (CSISP)-Cavanilles Institute for Biodiversity and Evolutionary Biology (University of Valencia), Valencia, Spain.
authors.forename: Francesc
authors.initials: F
authors.lastname: Peris-Bondia
authors.forename: Amparo
authors.initials: A
authors.lastname: Latorre
authors.forename: Alejandro
authors.initials: A
authors.lastname: Artacho
authors.forename: Andrés
authors.initials: A
authors.lastname: Moya
authors.forename: Giuseppe
authors.initials: G
authors.lastname: D'Auria
mesh_terms: D000328:Adult; D001419:Bacteria / Q000145:classification / Q000235:genetics*; D015373:Bacterial Typing Techniques; D044822:Biodiversity; D005243:Feces / Q000382:microbiology*; D005434:Flow Cytometry; D041981:Gastrointestinal Tract / Q000382:microbiology*; D006801:Humans; D017404:In Situ Hybridization, Fluorescence; D054892:Metagenome / Q000235:genetics*; D016133:Polymerase Chain Reaction; D012329:RNA, Bacterial / Q000235:genetics; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D012680:Sensitivity and Specificity; D017422:Sequence Analysis, DNA
chemical_list: D012329:RNA, Bacterial; D012336:RNA, Ribosomal, 16S