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Obesity alters gut microbial ecology
Ruth E. Ley, Fredrik Bäckhed, Peter Turnbaugh, Catherine A.
Lozupone, Robin D. Knight, and Jeffrey I. Gordon
What was known about the relationship between gut microbiome and obesity before this
paper was published?
• Gut microorganisms help to extract extra calories from indigestible polysaccharides in
our diet.
• Studies using germ free mouse have shown that Fiaf, a circulating inhibitor pf
lipoprotein lipase (LPL) regulates the absorption of this energy in adipocytes.
• The heritability of obesity, as defined by having a body mass index of 30 or more, is
estimated to be 64-84%.
Hypothesis?
Differences in gut microbial ecology is an important
factor affecting energy homeostasis
Methods?
The reseachers use C57BL mice that were homozigous for a mutation in the
leptine gene that is associated with obese phenotype (ob/ob), there lean (ob/+)
and wild type (+/+) siblings.
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Amplify 16S rRNA genes using PCR. Why?
The PCR products were sequenced aligned and BLASTed.
Phylogenies were inferred using ML, MP and BI.
Communities were clustered using UNIFRAC
Results
Dominance of the Bacteroidetes and Firmicutes in distal intestine of mice
A Deep-Branching Clade of the Cyanobacteria in the Guts of Mice and Other Animals.
Analysis revealed a coherent gut-associated clade rooted deep in the Cyanobacteria, a
division whose members perform oxygenic photosynthesis.
Kinship Has a Strong Effect on Microbial Diversity.
The results revealed that mothers and their offspring shared cecal microbiotas with
similar community membership, regardless of their ob genotype.
This characteristic held for both generations; i.e., mothers that were siblings (M1
and M3) shared microbiotas of similar composition, and the microbiotas of their
offspring (cousins) were similar.
Obesity Correlates with a Shift in the Abundance of Bacteroidetes and Firmicutes.
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