Systematic genome assessment of B-vitamin biosynthesis suggests co-operation among gut microbes.
Level 5 - mechanism / opinion, no new human data
Level 5 by design analogy (in silico comparative genomic analysis of bacterial reference genomes).
PubMed 25941533 · doi:10.3389/fgene.2015.00148
What was done
Using the PubSEED platform, researchers systematically analyzed the annotated genomes of 256 common human gut bacteria for the presence or absence of de novo biosynthesis pathways for eight B-vitamins: biotin, cobalamin, folate, niacin, pantothenate, pyridoxine, riboflavin, and thiamin. In silico predictions were evaluated against published experimental data for 16 bacterial species to assess predictive accuracy, and pathway distributions were examined to assess metabolic complementarity between species.
What was found
Each of the eight B-vitamins was predicted to be synthesized by 40% to 65% of the 256 analyzed gut bacterial genomes. Pathway distribution varied from organisms possessing all eight biosynthesis pathways to those containing zero de novo pathways. Predictions agreed with published experimental data in 88% of cases across the 16 evaluated organisms. Several organism pairs displayed complementary synthesis pathway patterns, suggesting metabolic co-operation and cross-feeding.
Why it matters
This study provides a comprehensive genomic assessment of B-vitamin production potential across common gut microbes, suggesting that microbial cross-feeding supports non-producing bacteria and that gut microbiome composition may affect host dietary vitamin needs.
Limits
The study is primarily computational and based on automated genome annotations. Experimental validation was limited to published literature from only 16 species. The study did not measure in vivo gene expression, absolute vitamin synthesis rates, cross-feeding flux, or actual contribution to host systemic vitamin status.
Cited by
- supports All eight essential B vitamins are synthesized by the human gut microbiome.