The devil lies in the details: how variations in polysaccharide fine-structure
impact the physiology and evolution of gut microbes
#MMPMID25026064
Martens EC
; Kelly AG
; Tauzin AS
; Brumer H
J Mol Biol
2014[Nov]; 426
(23
): 3851-65
PMID25026064
show ga
The critical importance of gastrointestinal microbes to digestion of dietary
fiber in humans and other mammals has been appreciated for decades. Symbiotic
microorganisms expand mammalian digestive physiology by providing an armament of
diverse polysaccharide-degrading enzymes, which are largely absent in mammalian
genomes. By out-sourcing this aspect of digestive physiology to our gut microbes,
we maximize our ability to adapt to different carbohydrate nutrients on
timescales as short as several hours due to the ability of the gut microbial
community to rapidly alter its physiology from meal to meal. Because of their
ability to pick up new traits by lateral gene transfer, our gut microbes also
enable adaption over time periods as long as centuries and millennia by adjusting
their gene content to reflect cultural dietary trends. Despite a vast amount of
sequence-based insight into the metabolic potential of gut microbes, the specific
mechanisms by which symbiotic gut microorganisms recognize and attack complex
carbohydrates remain largely undefined. Here, we review the recent literature on
this topic and posit that numerous, subtle variations in polysaccharides
diversify the spectrum of available nutrient niches, each of which may be best
filled by a subset of microorganisms that possess the corresponding proteins to
recognize and degrade different carbohydrates. Understanding these relationships
at precise mechanistic levels will be essential to obtain a complete
understanding of the forces shaping gut microbial ecology and genomic evolution,
as well as devising strategies to intentionally manipulate the composition and
physiology of the gut microbial community to improve health.
free
free
free
