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The narrow range of abundant specialists suggests that host selection and drift through ecological isolation may have caused a significant portion of intestinal bacteria to deviate from the nearly universal abundance-occupancy relationship.

The discovery of such intimate associations 249211 host and microbe led to the indirect treatment of infected individuals through direct manipulation of their microbiota 6 Reciprocal gut microbiota transplants from zebrafish and mice to germ-free recipients reveal host habitat selection.

Funding Statement The U. The application of ecological theory toward an understanding of the human microbiome.

Loess curves on plots of abundance versus occupancy suggested that the relationship between maximum OTU abundance and occupancy was positive and linear within a range Fig. The five families containing the most specialist OTUs within each phylum are displayed. Square root transformations followed by Wisconsin transformation see?

This presumption was supported by both the low occupancy of a large portion of OTUs and the observation of a positive abundance-occupancy relationship. In turn, host type, immune system, diet 9age 510associations with cohabitants 11and other factors shape the microbial community structure in a host-specific fashion Bacteroidetes composed the sixth, second, and third most abundant groups in birds, mammals, and fish, respectively.

General descriptions of human and cattle data sets were reported previously 24 Fisherb Sandra L. Microbes help maintain homeostasis by exchanging signals with mammalian immune, circulatory, digestive, and neuroendocrine organ systems 78and although such specific interactions have been investigated in only a few model species, they are thought to play important roles in the physiologies of most vertebrates.


We also found that OTU clustering parameters had little effect on the abundance-occupancy relationships. In this study, 249921 analyzed sequences from the bacterial V6 hypervariable region of the 16S rRNA genes from animal fecal samples to investigate bacterial distributions within microbial communities sampled from members of Aves birdsMammalia mammalsand Actinopterygii pey fish. EPA peer and administrative review and has been approved for external publication.

Fish gut contents were removed surgically and stored in 1.

In contrast to previous studies that show clear abundance-occupancy relationships in large organisms, which suggest a lack of a fitness trade-off between generalist and specialist niches, these results confirm that bacteria can benefit significantly by acquiring specialist lifestyles.

The taxonomic compositions of host communities differed greatly between species; however, all species contained a large proportion of bacteria belonging to the Firmicutes phylum Fig.


McLellanb Mitchell L. Delineation of host-microbe associations has applied benefits ranging from clinical treatments to protecting our natural waters. Evolution of mammals and their gut microbes. Transfer of intestinal microbiota from lean donors increases insulin sensitivity in individuals with metabolic syndrome.

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Two measures of abundance were used: The relative abundance of Lachnospiraceae in mammalian guts was noted previously, and genomic analysis suggests that this group’s abilities to form endospores; produce butyrate, a compound thought to be important in host physiology; and carry genes important for protein interactions and signal transduction play prominently in this group’s ability to evolve host-specific preferences Firmicutes composed the largest portion of bacterial communities in birds and mammals, while Proteobacteria composed the lwy portion in fish.


As part of the CLAM tests, sample coverage correction based on the number of observed singletons was applied to rare OTUs whose counts were below 10 sequences per group.

These methods do not distinguish specialists that have a high abundance within a small proportion of hosts from lower-abundance specialists found in a large proportion of hosts. In dogs, the abundance of Erysipelotrichaceae drops significantly in diseased states, while no significant change occurs for most other bacterial taxa 54which lry that canine-associated OTUs within this environment may have specialized not only to the canine gut environment but also to a healthy-host state within this environment.

Genome Biol Evol 6: Taxon-area and distance-decay relationships for microbes have been observed in salt marsh sediments 1718 and tree holes 19 Animals in a bacterial world, a new imperative for the life sciences. We investigated the interspecific abundance-occupancy relationship, where widespread taxa tend to be more abundant than narrowly distributed taxa, among operational taxonomic units OTUs within and among host species.

Diversity 42921 indicate that we observed roughly half of all OTUs present in samples Table 2.

Decreto 198 De 2003

Experimental tests of the bacterial distance-decay relationship. Functional metagenomic analysis may provide a more accurate picture of the overall community metabolic capability, while single-cell isolation and genome sequencing techniques may be more useful in linking functional capacity to 16S rRNA data such as those produced in this study.

Taking into account abundance, specialist OTUs accounted for Author information Article notes Copyright and License information Disclaimer.