Transfer of carbohydrate-active enzymes from marine bacteria to Japanese gut microbiota.
Level 5 - mechanism / opinion, no new human data
Bench enzyme characterization and comparative gut metagenomic analysis (basic science / mechanistic).
PubMed 20376150 · doi:10.1038/nature08937
What was done
Researchers biochemically characterized porphyranase enzymes from the marine bacterium Zobellia galactanivorans that degrade the sulphated polysaccharide porphyran from red algae (Porphyra). They analyzed whether genes encoding porphyranases, agarases, and associated proteins were transferred to the human gut symbiont Bacteroides plebeius isolated from Japanese individuals, and compared gut metagenome datasets between Japanese and North American populations.
What was found
Genes encoding porphyranases and agarases were identified in Bacteroides plebeius and were frequent in metagenomic data from Japanese individuals, whereas they were absent in metagenome data from North American individuals. The abstract notes average Japanese seaweed consumption at 14.2 g per person per day, but specific participant sample sizes, exact gene prevalence percentages, and statistical values were not reported in the abstract.
Why it matters
This provides evidence of horizontal gene transfer from environmental marine microbes to human gut symbionts, showing that non-sterile dietary components can introduce novel metabolic capacities into the human microbiome.
Limits
The abstract omits sample sizes for the metagenome cohorts and quantitative effect sizes or prevalence rates. The link between seaweed consumption and gene transfer is an epidemiological and historical inference rather than a prospectively tested causal intervention.
Cited by
- supports Eating sushi provides the human gut with bacteria that facilitate the absorption and digestion of nutrients from seaweed.