Abstract
Degradation of lignocellulosic plant material in the mammalian digestive tract is accomplished by communities of anaerobic microorganisms that exist in symbiotic association with the host. Catalytic domains and substrate-binding modules concerned with plant polysaccharide degradation are found in a variety of anaerobic bacteria, fungi, and protozoa from the mammalian gut. The organization of plant cell wall-degrading enzymes, however, varies widely. The cellulolytic gram-positive bacterium Ruminococcus flavefaciens produces an elaborate cellulosomal enzyme complex that is anchored to the bacterial cell wall; assembly of the complex involves at least five different dockerin:cohesin specificities, and the R. flavefaciens genome encodes at least 180 dockerin-containing proteins that encompass a wide array of catalytic and binding activities. On the other hand, in the cellulolytic protozoan, Polyplastron multivesiculatum, individual plant cell wall-degrading enzymes appear to be secreted into food vacuoles, while the gram-negative bacterium Prevotella bryantii appears to possess a sequestration-type system for the utilization of soluble xylans. The system that is employed for polysaccharide utilization must play a major role in defining the ecological niche that each organism occupies within a complex gut community. 16S rRNA analyses are also revealing uncultured bacterial species closely adherent to fibrous substrates in the rumen and in the large intestine of animals and humans. The true complexity, both at a single organism and community level, of the microbial enzyme systems that allow animals to digest plant material is beginning to become apparent.
| Original language | English |
|---|---|
| Pages (from-to) | 280-288 |
| Number of pages | 9 |
| Journal | Annals of the New York Academy of Sciences |
| Volume | 1125 |
| DOIs | |
| Publication status | Published - Mar 2008 |
Keywords
- lignocellulose
- rumen
- cellulosome
- Ruminococcus
- Prevotella
- large intestine
- microbial ecology
- protozoan polyplastron-multivesiculatum
- bacterium ruminococcus-flavefaciens
- prevotella-ruminicola B(1)4
- 16s ribosomal-RNA
- human gut
- bacteroides-thetaiotaomicron
- microbial diversity
- gastrointestinal-tract
- molecular analysis
- sequence-analysis
Cite this
Plant cell wall breakdown by anaerobic microorganisms from the mammalian digestive tract. / Flint, Harry J.; Bayer, Edward A.
In: Annals of the New York Academy of Sciences, Vol. 1125, 03.2008, p. 280-288.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Plant cell wall breakdown by anaerobic microorganisms from the mammalian digestive tract
AU - Flint, Harry J.
AU - Bayer, Edward A.
PY - 2008/3
Y1 - 2008/3
N2 - Degradation of lignocellulosic plant material in the mammalian digestive tract is accomplished by communities of anaerobic microorganisms that exist in symbiotic association with the host. Catalytic domains and substrate-binding modules concerned with plant polysaccharide degradation are found in a variety of anaerobic bacteria, fungi, and protozoa from the mammalian gut. The organization of plant cell wall-degrading enzymes, however, varies widely. The cellulolytic gram-positive bacterium Ruminococcus flavefaciens produces an elaborate cellulosomal enzyme complex that is anchored to the bacterial cell wall; assembly of the complex involves at least five different dockerin:cohesin specificities, and the R. flavefaciens genome encodes at least 180 dockerin-containing proteins that encompass a wide array of catalytic and binding activities. On the other hand, in the cellulolytic protozoan, Polyplastron multivesiculatum, individual plant cell wall-degrading enzymes appear to be secreted into food vacuoles, while the gram-negative bacterium Prevotella bryantii appears to possess a sequestration-type system for the utilization of soluble xylans. The system that is employed for polysaccharide utilization must play a major role in defining the ecological niche that each organism occupies within a complex gut community. 16S rRNA analyses are also revealing uncultured bacterial species closely adherent to fibrous substrates in the rumen and in the large intestine of animals and humans. The true complexity, both at a single organism and community level, of the microbial enzyme systems that allow animals to digest plant material is beginning to become apparent.
AB - Degradation of lignocellulosic plant material in the mammalian digestive tract is accomplished by communities of anaerobic microorganisms that exist in symbiotic association with the host. Catalytic domains and substrate-binding modules concerned with plant polysaccharide degradation are found in a variety of anaerobic bacteria, fungi, and protozoa from the mammalian gut. The organization of plant cell wall-degrading enzymes, however, varies widely. The cellulolytic gram-positive bacterium Ruminococcus flavefaciens produces an elaborate cellulosomal enzyme complex that is anchored to the bacterial cell wall; assembly of the complex involves at least five different dockerin:cohesin specificities, and the R. flavefaciens genome encodes at least 180 dockerin-containing proteins that encompass a wide array of catalytic and binding activities. On the other hand, in the cellulolytic protozoan, Polyplastron multivesiculatum, individual plant cell wall-degrading enzymes appear to be secreted into food vacuoles, while the gram-negative bacterium Prevotella bryantii appears to possess a sequestration-type system for the utilization of soluble xylans. The system that is employed for polysaccharide utilization must play a major role in defining the ecological niche that each organism occupies within a complex gut community. 16S rRNA analyses are also revealing uncultured bacterial species closely adherent to fibrous substrates in the rumen and in the large intestine of animals and humans. The true complexity, both at a single organism and community level, of the microbial enzyme systems that allow animals to digest plant material is beginning to become apparent.
KW - lignocellulose
KW - rumen
KW - cellulosome
KW - Ruminococcus
KW - Prevotella
KW - large intestine
KW - microbial ecology
KW - protozoan polyplastron-multivesiculatum
KW - bacterium ruminococcus-flavefaciens
KW - prevotella-ruminicola B(1)4
KW - 16s ribosomal-RNA
KW - human gut
KW - bacteroides-thetaiotaomicron
KW - microbial diversity
KW - gastrointestinal-tract
KW - molecular analysis
KW - sequence-analysis
U2 - 10.1196/annals.1419.022
DO - 10.1196/annals.1419.022
M3 - Article
VL - 1125
SP - 280
EP - 288
JO - Annals of the New York Academy of Sciences
JF - Annals of the New York Academy of Sciences
SN - 0077-8923
ER -