Bacteroides plebeius

Classification

Domain: Bacteria Phylum: Bacteroidetes Class: Bacteroidia Order: Bacteroidales Family: Bacteroidaceae Genus : Bacteroides Species: plebeius

Species

Bacteroides plebeius

Description and Significance

Bacteroides plebeius is gram-negative, non-motile, Anaerobic, Bacilli-shaped bacteria found in the gut of specific human populations [1][2]. Notably, it has the ability to produce porphyranase, an enzyme that can break down porphyan, a complex carbohydrate found in red seaweed. The prevailing theory is that it received this ability via horizontal gene transfer from an aquatic microbe, Zobellia galactanivorans that was ingested by a human. Although this microbe was unable to colonize the gut, it is believed to have transferred its porphyranase-coding genes to B. plebeius while passing through the digestive system. [2]

Genome Structure

The median genome size of recorded B. plebeius strains is 4.42 Mb, with a median G/C% of 44.3. [1] B. plebeius contains a polysaccharide utilization locus (PUL) that is believed to originate from the marine bacterium Zobellia galactanivorans. Specifically, this PUL contains two genes, BACPLE_01689 and BACPLE_01693, that code for β-porphyranases, which give B. plebeius the unique ability to break down porphyran. [2]

Cell Structure, Metabolism, and Life Cycle

B. plebeius has the unique ability to break down porphyran, and it does this by producing porphyranase. Bacteroides produce CAZymes that the human genome cannot make. [3]

Ecology and Pathogenesis

Bacteroides are the most abundant microbes found in the intestines of mammals, existing in a mutualistic relationship with its host. However, if they become opportunistic pathogens if they are able to escape the gut. Many gut microbes, including B. plebeius, are able to produce carbohydrate active enzymes (CAZymes) that cannot be produced by the human genome. Marine algae contain sulphated polysaccharides, which are not found in terrestrial plants. B. plebeius has the unique ability to produce CAZymes that break down these sulphated polysaccharides

Author

Page authored by Ryan Curtiss, student of Prof. Jay Lennon at Indiana University